JP2009180357A - Control device for variable displacement pump motor type transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control device for a variable displacement pump motor type transmission capable of accumulating pressure from a closed circuit with which a pump motor communicates without changing a gear ratio. <P>SOLUTION: The control device comprises an accumulator communicating with a high pressure flow path which supplies a relatively high pressure fluid discharged by one variable displacement pump motor to the other variable displacement pump motor via a selector valve which has an opening/closing function, a target gear ratio calculating means (Step S8) for finding a target gear ratio to be set, and extrusion displacement control means (Steps S7-S15) for keeping the ratio of the extrusion displacement of one variable displacement type pump motor to that of the other at a value for setting the target gear ratio obtain by the target gear ratio calculating means when supplying the pressure fluid from the high pressure flow path to the accumulator and accumulating the pressure. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention includes at least two power transmission systems capable of transmitting power from a power source to a gear mechanism via a differential mechanism, respectively, and a variable displacement pump motor is connected to each differential mechanism. By providing a circuit that circulates the pressure fluid between the variable displacement pump motors, the fluid pressure generated by the mechanical torque transmission is utilized to transmit the torque in parallel with the mechanical torque transmission. The present invention relates to a transmission control device.

  A transmission configured to perform transmission of torque between a power source such as an engine and an output member by a mechanical transmission unit (MT) and a hydraulic transmission unit (HST) provided in parallel with each other, Patent Document 1, Patent Document 2, and the like.

  The transmission described in Patent Document 1 is generated by a hydraulic transmission and a mechanical transmission that changes the torque transmission path via the gear mechanism by switching the engagement / release state of the clutch, and a hydraulic pump. A hydraulic transmission that supplies pressure oil to the hydraulic motor and transmits torque from the hydraulic motor to the output member is arranged in parallel between the power source and the output member. The input shaft for the mechanical transmission unit and the pump shaft in the hydraulic transmission unit are connected by a gear that meshes with each other, and therefore the engine power is transmitted to the mechanical transmission unit and the hydraulic transmission unit via the gear. It is configured to be divided and transmitted. In the transmission described in Patent Document 1, an accumulator is connected to a closed circuit that allows a hydraulic pump and a hydraulic motor to communicate with each other. When the vehicle decelerates, the hydraulic motor is pumped by a running inertial force of the vehicle. And the capacity of the hydraulic pump is reduced, and the pressure oil generated by the hydraulic motor functioning as a pump is collected in an accumulator.

  The transmission described in Patent Document 2 is provided with a gear mechanism that changes a gear ratio between at least two intermediate shafts and an output member, and each intermediate shaft and a power source such as an engine are differentially provided. The variable displacement pump motors are connected to the respective differential mechanisms, and the pump motors are connected by a closed circuit. Therefore, in the transmission described in Patent Document 2, torque is transmitted from a power source to any one of the differential mechanisms, and a reaction force is generated by a pump motor connected to the differential mechanism. By inputting the torque, the torque is transmitted from the differential mechanism to the output member via the intermediate shaft and the gear mechanism. At the same time, the pump motor that provides the reaction torque generates fluid pressure, which is supplied to the other pump motor and functions as a motor, so that the torque output from the motor is the differential of the other. It is transmitted to the output member via the mechanism and the other intermediate shaft and the gear mechanism. In this way, the torque transmitted mechanically by causing the pump motor to function as so-called reaction force means and the torque transmitted via the exchange of pressure fluid between the pump motors are combined to the output member. Therefore, the transmission gear ratio is a transmission gear ratio that combines mechanical transmission and hydraulic transmission. As a result, the gear ratio can be changed steplessly by continuously changing the extrusion volume of each pump motor, thus functioning as a continuously variable transmission.

  The hydrostatic system is configured to connect the hydraulic pump and the hydraulic motor in a closed circuit, supply the hydraulic pressure generated by driving the hydraulic pump with the engine to the hydraulic motor, and output the torque generated by the hydraulic motor. A transmission is described in Patent Document 3. In the transmission described in Patent Document 3, a charge pump is provided that stores pressure oil in a pressure accumulator and supplies pressure oil to a closed circuit.

Japanese Patent Laid-Open No. 11-6557 JP 2007-64269 A JP 2001-324014 A

  Both the transmission described in Patent Document 1 and the transmission described in Patent Document 2 use both mechanical transmission and fluid transmission, and the transmission ratio in mechanical transmission and the transmission ratio in fluid transmission. Are combined so as to be the overall gear ratio of the apparatus. However, there is a great difference between the transmission described in Patent Document 1 and the transmission described in Patent Document 2, and the power recovery technique described in Patent Document 1 is the transmission described in Patent Document 2. Cannot be diverted to equipment immediately.

  That is, the transmission described in Patent Document 1 has a configuration in which a mechanical transmission and a hydrostatic transmission are provided in parallel between an input shaft and an output shaft, and are connected to the output shaft during pressure accumulation. The hydraulic motor is functioned as a pump, and the hydraulic pressure is stored in a pressure accumulator. In this case, the discharge pressure is increased by reducing the capacity of the hydraulic motor that functions as a pump, and the torque associated with the function of the hydraulic motor as a pump in this way becomes part of the braking torque. At the time of accumulating pressure, the capacity of the hydraulic pump on the input side is set to zero and is idled. Therefore, in the transmission described in Patent Document 1, the output shaft is connected to the engine via the mechanical transmission during pressure accumulation, while the hydrostatic transmission is connected to the hydraulic motor. Thus, the hydraulic pump is not involved in torque transmission. Therefore, even if the transmission gear ratio is changed by sending the pressure oil generated by the hydraulic motor to the accumulator and accumulating the pressure, the torque of the output shaft can be controlled by the hydraulic motor functioning as a pump. Therefore, a desired vehicle speed can be set or maintained.

  On the other hand, the speed change device described in Patent Document 2 is a state in which torque is transmitted to the output shaft through two speed change gear pairs other than the so-called fixed speed ratio (or fixed speed). In this case, one of the variable displacement pump motors functions as a pump so that a reaction torque is applied to the differential mechanism functioning as a power split device, and the other variable displacement pump motor The pressure fluid is supplied from the variable displacement pump motor and functions as a motor, and the output torque is transmitted to the differential mechanism functioning as the other power split device. That is, in the speed change device described in Patent Document 2, both variable displacement pump motors are involved in torque transmission regardless of whether they are accelerating or decelerating. A gear ratio according to the flow rate is set. Therefore, in the transmission described in Patent Document 2, if the pressure fluid discharged from one variable displacement pump motor that functions as a pump is supplied to the pressure accumulator to accumulate pressure, the other that functions as a motor is used. Since the amount of pressure fluid supplied to the variable displacement pump motor decreases, the overall transmission ratio of the transmission changes, as well as the power between each variable displacement pump motor and the output shaft. Since the differential mechanism that functions as a dividing device is interposed and the output shaft is not connected to the variable displacement pump motor, the intended vehicle speed cannot be set or maintained.

  As described in Patent Document 3, when recovering power by sending pressure oil to the accumulator, it is possible to supply pressure oil from a charge pump, but the pressure oil is used as a pump. Since it is supplied to the suction side of the functioning pump motor, the amount of pressure fluid supplied to the pump motor functioning as the motor is not necessarily sufficient or changes, so that the transmission ratio is maintained. Is difficult, or when used in a vehicle, the vehicle speed may change.

  The present invention has been made paying attention to the above technical problem, and when recovering power with a transmission having a configuration in which a variable displacement pump motor is involved in so-called mechanical transmission, the gear ratio is set as expected. It is an object of the present invention to provide a control device that can maintain or set and recover power.

  In order to achieve the above object, the invention of claim 1 is characterized in that at least two differential mechanisms to which variable displacement pump motors that selectively provide reaction force torque and driving torque are respectively connected are connected to a power source. In addition to being connected in parallel, a transmission mechanism is provided between the differential mechanism and the output member. Further, the variable displacement pump motors are communicated with each other via a closed circuit, and fluid is supplied to the closed circuit. In the control apparatus for a variable displacement pump motor type transmission provided with a charge pump that performs the above operation, relatively high pressure fluid discharged from one of the variable displacement pump motors is transferred to the other variable displacement pump motor. A pressure accumulator communicated with a high-pressure channel to be supplied via a switching valve having an opening / closing function; target gear ratio calculating means for obtaining a target gear ratio to be set; and Extrusion volume control means for maintaining the ratio between the extrusion volumes of the variable displacement pump motors at a value for setting the target speed ratio obtained by the target speed ratio calculation means when supplying pressure fluid to the pressure device and accumulating pressure It is characterized by having.

  The invention of claim 2 is the invention of claim 1, further comprising target pressure setting means for setting a target pressure to be stored in the pressure accumulator, wherein the pushing volume control means is a pushing volume of each variable capacity pump motor. And a control unit for the variable displacement pump motor type transmission, including means for controlling the sum so that the target pressure set by the target pressure setting means is maintained while maintaining the ratio.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, when the pressure difference between the pressure of the high-pressure channel and the pressure of the pressure accumulator is reduced to a predetermined value, the pressure accumulation in the pressure accumulator is terminated. The control apparatus for a variable displacement pump motor type transmission further includes a pressure accumulation end means for performing the operation.

  According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, the extrusion volume control means uses a pressure fluid from the high-pressure channel as an extrusion volume that is changed in order to maintain the ratio with the accumulated pressure. The variable displacement pump motor type transmission control apparatus includes means for changing the extrusion volume of the variable displacement pump motor that functions as a motor.

  According to a fifth aspect of the present invention, in the fourth aspect of the invention, the extrusion volume control means includes means for setting an extrusion volume of a variable displacement pump motor that functions as the motor in accordance with a flow rate of pressure fluid with respect to the pressure accumulator. A control apparatus for a variable displacement pump motor type transmission.

  According to a sixth aspect of the present invention, in the invention according to any one of the second to fifth aspects, the extrusion volume control means adds the extrusion volume of each of the variable displacement pump motors to the target pressure and outputs the output torque of the power source. Alternatively, the control device for a variable displacement pump motor type transmission includes means for controlling the power source based on a drag torque of the power source when the power source is forcibly rotated by an external force.

  The invention of claim 7 is the invention according to any one of claims 3 to 6, wherein the pressure accumulation end means calculates the ratio and sum of the extrusion volumes of the variable displacement pump motors when the pressure accumulation in the pressure accumulator is terminated. A control device for a variable displacement pump motor type transmission comprising means for gradually decreasing the flow rate of the pressure fluid to the pressure accumulator while maintaining.

  According to an eighth aspect of the present invention, in any one of the first to seventh aspects, any one of the variable displacement pump motors functions as a pump to generate a relatively high pressure fluid in the high pressure flow path. In a state where the pressure of the pressure accumulator or the amount of the pressure fluid in the pressure accumulator becomes equal to or less than a predetermined value in a state where The control apparatus for a variable displacement pump motor type transmission further comprising means.

  According to a ninth aspect of the present invention, in the invention according to any one of the first to eighth aspects, the switching valve includes a flow path that has a relatively high pressure when the power source is driven to output power, and the power source is an external force. The control apparatus for a variable displacement pump motor type transmission includes a valve that switches to a flow path that is forcedly rotated and has a high pressure when driven to communicate the accumulator.

  According to the first aspect of the present invention, pressure can be accumulated by supplying a relatively high pressure fluid discharged from one variable displacement pump motor to the accumulator via the switching valve. In this case, if the power for driving the one variable displacement pump motor is so-called surplus power, energy recovery (regeneration) is performed. Even if the flow rate of the pressure fluid flowing from the variable displacement pump motor functioning as a pump to the variable displacement pump motor functioning as a motor decreases due to the flow of the pressure fluid to the accumulator, each variable displacement pump motor Since the ratio of the extrusion volume is maintained so as to set the target gear ratio, it is possible to prevent or suppress a change in the gear ratio due to pressure accumulation or a shift of the gear ratio from the target value.

  According to the invention of claim 2, the ratio of the extrusion volume of each variable displacement pump motor is maintained at a value for setting the target gear ratio, and the sum thereof becomes a value for setting the target pressure for pressure accumulation. Be controlled. Therefore, a pressure fluid having a substantially constant pressure can be stored in the pressure accumulator, and a stable pressure can be obtained when the pressure fluid stored in the pressure accumulator is used.

  According to the invention of claim 3, since the end of the pressure accumulation is determined based on the differential pressure between the pressure of the high pressure flow path and the pressure of the pressure accumulator, until the time point when the pressure change is switched to the subsequent shift control, It becomes possible to detect or determine the flow rate of the pressure fluid with respect to the pressure accumulator, and therefore, switching from the pressure accumulation control to the shift control can be performed continuously. In particular, as in the invention of claim 7, by gradually reducing the flow rate of the pressure fluid to the pressure accumulator, the change in the flow rate of the pressure fluid to each variable displacement pump motor becomes smooth, preventing a shock associated with the end of pressure accumulation or Can be reduced.

  According to the invention of claim 4, the amount of pressure fluid in one variable displacement pump motor functioning as a pump is driven by the power of the power source or the power transmitted from the output member side. Therefore, the flow rate of the other variable displacement pump motor functioning as a motor is sent to the accumulator in the preceding stage, while the amount is in accordance with the rotation speed and the extrusion volume. As a result, the pressure fluid is reduced as compared with the case where pressure fluid is simply circulated between the variable displacement pump motors as in normal shift control. The extrusion volume is controlled so as to compensate for the effect of the decrease in the flow rate of the pressure fluid, and the control amount, that is, the extrusion volume, is controlled so as to become the above ratio, and as a result, the gear ratio deviates from the target value during pressure accumulation. It can be prevented or suppressed.

  According to the invention of claim 5, when accumulating pressure, the extrusion volume of the variable displacement pump motor that functions as a motor is controlled according to the flow rate of the pressure fluid flowing to the accumulator, so that it functions as a motor. The torque of the variable displacement pump motor is maintained at the desired torque by making up for the influence of the decrease in the flow rate of the pressure fluid, and as a result, the change in the gear ratio due to pressure accumulation can be prevented or suppressed.

  According to the sixth aspect of the present invention, the pressure that can be stored in the pressure accumulator is lower as the sum of the extrusion volumes is larger, and is smaller as the sum is smaller, and is higher as the input driving torque or drag torque is larger. Since these torques become lower as the torque becomes smaller, the target pressure is determined, so that the extrusion volume is controlled according to the driving torque or dragging torque, and the target pressure can be generated.

  According to the eighth aspect of the present invention, the determination of execution of the pressure accumulation is performed based on the pressure of the pressure accumulator or the remaining amount of the pressure fluid, so that a pressure fluid having a predetermined pressure can be always secured.

  According to the ninth aspect of the invention, pressure accumulation or energy recovery is performed both when the power source is rotating while the power source is outputting power and when the power source is forcibly rotated by an external force. It can be carried out.

  Next, the present invention will be described based on specific examples. First, the transmission that is the subject of the present invention will be described. The transmission that is the subject of the present invention includes at least two power transmission paths, and the output member from the power source via both power transmission paths. Thus, the transmission can continuously change the speed ratio, which is the ratio of the rotational speeds of the power source and the output member.

  More specifically, each of the power transmission paths described above includes a variable displacement pump motor that functions as a pump and a motor, respectively, and transmits torque according to the extrusion volume of the variable displacement pump motor. Further, the variable displacement pump motors are communicated with each other so as to exchange pressure fluid with each other. Accordingly, when one of the variable displacement pump motors functions as a pump, torque corresponding to the extrusion volume is transmitted from the power source to the output member, and at the same time, from one variable displacement pump motor to the other variable displacement pump. Pressure fluid is supplied to the motor, and the other variable displacement pump motor functions as a motor. That is, power transmission via the pressure fluid is performed in parallel. The torque is transmitted to the output member via the other power transmission path. As a result, the torque transmitted to the output member is the sum of the torque transmitted through each power transmission path, and the torque transmitted through the pressure fluid changes according to each extrusion volume. Eventually, the gear ratio changes continuously.

  Each power transmission path is provided with a transmission mechanism such as a gear pair or a winding transmission mechanism with different gear ratios, and when transmitting torque to the output member via only one power transmission path, The overall gear ratio is determined by the gear ratio of the transmission mechanism in the power transmission path. If such a gear ratio is referred to as a fixed gear ratio (or a fixed speed), power transmission via pressure fluid does not occur in a state where the fixed gear ratio is set, so power loss is unlikely to occur. Efficient transmission state. Note that a switching mechanism such as a clutch mechanism is preferably included in each transmission mechanism so that only one of the transmission mechanisms is involved in torque transmission, or between the power source or output member and the transmission mechanism. It is preferable to provide a switching mechanism.

  Since the transmission targeted by this invention is configured to transmit power via pressure fluid, as described above, the hydrostatic mechanical having the function of setting the gear ratio by mechanical power transmission -It is configured as a transmission (HMT). The mechanical transmission portion can be appropriately configured as necessary. A mechanism in which a gear pair that is always meshed is selected by a clutch mechanism or a synchronous coupling mechanism, or a plurality of planetary gear mechanisms or compound planets. A configuration in which a plurality of gear ratios can be set by a gear mechanism can be employed. Further, the variable displacement pump motor may be configured to use a variable displacement pump motor as the reaction force means in addition to the configuration in which the variable displacement pump motor is interposed in series between the power source and the output member.

  FIG. 4 shows an example of a transmission targeted by the present invention. This is an example configured as a transmission for a vehicle, and four forward speeds and one reverse speed are set as a so-called fixed speed ratio (fixed speed) that can be set by transmitting torque without passing through a fluid. This is a configured example. That is, in the transmission TM that is the object of the present invention mounted on the vehicle Ve, the input member 2 is connected to the power source (E / G) 1, and the difference corresponding to the power split mechanism from the input member 2. Torque is transmitted to the dynamic mechanism. As the differential mechanism, various types of conventionally known structures can be adopted. In the example shown in FIG. 4, the first planetary gear mechanism 3 (that is, the first power split mechanism) and the second planetary gear are used. Mechanism 4 (that is, the second power split mechanism) is employed.

  The power source 1 may be a general power source used in a vehicle such as an internal combustion engine, an electric motor, or a combination of these. Further, an appropriate transmission means such as a damper, a clutch, or a torque converter may be interposed between the power source 1 and the input member 2.

  The first planetary gear mechanism 3 is disposed on the same axis as the input member 2, the second planetary gear mechanism 4 is separated outward in the radial direction of the first planetary gear mechanism 3, and the respective central axes are parallel to each other. They are arranged in parallel. As each of these planetary gear mechanisms 3 and 4, an appropriate type of planetary gear mechanism such as a single pinion type or a double pinion type can be adopted. The example shown in FIG. 4 is an example constituted by a single pinion type planetary gear mechanism, and is a sun gear 3S, 4S which is an external gear, and a ring gear which is an internal gear arranged concentrically with respect to the sun gear 3S, 4S. 3R, 4R, and carriers 3C, 4C holding pinion gears meshed with these sun gears 3S, 4S and ring gears 3R, 4R so as to be rotatable and revolved. The input member 2 is connected to the ring gear 3R in the first planetary gear mechanism 3, and the ring gear 3R serves as an input element. The planetary gear mechanisms 3 and 4 preferably have the same gear ratio (ratio between the number of teeth of the sun gear and the number of teeth of the ring gear), but the invention is not limited to this.

  Further, a counter drive gear 5 is attached to the input member 2, and an idle gear 6 is engaged with the counter drive gear 5, and a counter driven gear 7 is engaged with the idle gear 6. The counter driven gear 7 is arranged on the same axis as the second planetary gear mechanism 4 and is connected to the ring gear 4R of the second planetary gear mechanism 4 so as to rotate together. Therefore, in the second planetary gear mechanism 4, the ring gear 4R serves as an input element. The ring gears 3R and 4R, which are input elements of the planetary gear mechanisms 3 and 4, are configured so that the counter gear pair includes the idle gear 6, and thus rotate in the same direction. The power source 1 may be connected to any one of the counter drive gear 5, the counter driven gear 7, and the idle gear 6.

  The carrier 3C in the first planetary gear mechanism 3 is an output element, and the first intermediate shaft 8 corresponding to the first transmission shaft is coupled to the carrier 3C so as to rotate together. The first intermediate shaft 8 is a hollow shaft, and a motor shaft 9 is rotatably inserted therein. One end of the motor shaft 9 is a sun gear that is a reaction force element in the first planetary gear mechanism 3. It is connected to 3S so as to rotate together.

  The second planetary gear mechanism 4 has the same configuration, and the carrier 4C serves as an output element, and the second intermediate shaft 10 corresponding to the second transmission shaft rotates integrally with the carrier 4C. So that they are connected. The second intermediate shaft 10 is a hollow shaft, and a motor shaft 11 is rotatably inserted therein. One end of the motor shaft 11 is a sun gear that is a reaction force element in the second planetary gear mechanism 4. 4S is connected to rotate integrally.

  The other end of the motor shaft 9 is connected to the output shaft (rotor shaft) of the variable displacement pump motor 12. The variable displacement pump motor 12 is, for example, a hydraulic pump capable of changing the discharge capacity, such as a slant shaft pump, a swash plate pump, or a radial piston pump. It functions as a motor by discharging pressure fluid (pressure oil) and supplying pressure fluid from the discharge port or suction port. In the following description, the variable displacement pump motor 12 is referred to as a first pump motor 12 and is represented as PM1 in the drawing.

  The other end of the motor shaft 11 is connected to the output shaft (rotor shaft) of the variable displacement pump motor 13. The variable displacement pump motor 13 is an example of a hydraulic pump capable of changing the discharge capacity, such as an inclined shaft pump, a swash plate pump, or a radial piston pump, like the first pump motor. The pressure fluid (pressure oil) is discharged by functioning as a pump by rotating and supplying a pressure fluid from the discharge port or the suction port, thereby functioning as a motor. In the following description, the variable displacement pump motor 13 is referred to as a second pump motor 13 and is indicated as PM2 in the figure.

  The pump motors 12 and 13 are communicated with each other by oil passages 14 and 15 so that the pressure oil, which is a pressure fluid, can be transferred to each other. That is, the suction ports 12 </ b> S and 13 </ b> S are communicated with each other through the oil passage 14, and the discharge ports 12 </ b> D and 13 </ b> D are communicated with each other through the oil passage 15. Therefore, a closed circuit CC is formed by the oil passages 14 and 15. The suction ports 12S and 13S in the pump motors 12 and 13 are ports for sucking fluids such as oil when the pump motors 12 and 13 rotate in the same direction as the power source 1, and the discharge ports 12D. , 13D are ports for discharging fluid such as oil during forward rotation. A mechanism for hydraulic control in the closed circuit CC will be described later.

  An output shaft 16 corresponding to the output member of the present invention is arranged in parallel with each of the intermediate shafts 8 and 10 described above. A transmission mechanism for setting a predetermined gear ratio is provided between the output shaft 16 and each of the intermediate shafts 8 and 10. The transmission mechanism in the present invention is not limited to a mechanism that transmits power at a fixed gear ratio, and a mechanism with a variable gear ratio can be employed. In the example shown in FIG. 4, power is transmitted at a fixed gear ratio. A plurality of gear pairs 17, 18, 19, and 20 for transmitting the above are employed.

  More specifically, a fourth speed drive gear 17A and a second speed drive gear 18A are arranged on the first intermediate shaft 8 in order from the first planetary gear mechanism 3 side, and the fourth speed drive gear 17A. And the second speed drive gear 18 </ b> A are rotatably fitted to the first intermediate shaft 8. A fourth speed driven gear 17B meshed with the fourth speed drive gear 17A and a second speed driven gear 18B meshed with the second speed drive gear 18A are attached to the output shaft 16 so as to rotate integrally. Yes.

  Further, a third speed drive gear 19A meshed with the fourth speed driven gear 17B and a first speed drive gear 20A meshed with the second speed driven gear 18B are rotatable on the second intermediate shaft 10. It is made to fit. Accordingly, the fourth speed driven gear 17B also serves as the third speed driven gear 19B, and the second speed driven gear 18B also serves as the first speed driven gear 20B. Here, the gear ratio of each gear pair 17, 18, 19, and 20 (ratio of the number of teeth of the driven gear to the number of teeth of each drive gear) will be described. The second speed gear pair 18, the third speed gear pair 19, and the fourth speed gear pair 17 are configured to decrease in order.

  Furthermore, a starting gear pair 21 is provided. The starting gear pair 21 is for transmitting the power to the output shaft 16 together with the first speed gear pair 20 so as to increase the driving force at the time of starting sufficiently and sufficiently. A start drive gear 21 </ b> A attached to rotate integrally with the motor shaft 9 on the motor 12 side and a start driven gear 21 </ b> B attached to the output shaft 16 so as to be rotatable are provided.

  A switching mechanism is provided for allowing each of the gear pairs 17, 18, 19, 20, and 21 described above to transmit torque between any of the intermediate shafts 8 and 10 and the output shaft 16. In short, this switching mechanism is a mechanism that selectively transmits torque, and employs a conventionally known mechanism such as a dog clutch mechanism, a synchronous coupling mechanism (synchronizer), and a friction engagement mechanism such as a friction clutch. FIG. 4 shows an example employing a synchronizer.

  The synchronizer basically moves the sleeve that rotates together with the rotating shaft in the axial direction, and engages with the spline of the rotating member that is mounted so as to rotate relative to the rotating shaft. When the kniter ring is gradually brought into frictional contact with the rotating member, the rotating shaft and the rotating member are synchronized to connect the rotating shaft and the rotating member. On the output shaft 16, a first synchronizer (hereinafter referred to as a first synchronizer) 22 is provided at a position adjacent to the starter driven gear 21B. The first sync 22 moves its sleeve to the left side of FIG. 4 to connect the starter driven gear 21B to the output shaft 16, and the starter gear pair 21 torques between the motor shaft 9 and the output shaft 16. Is configured to communicate.

  Further, on the second intermediate shaft 10, a second synchronizer (hereinafter referred to as a second synchronizer) 23 is provided between the third speed drive gear 19A and the first speed drive gear 20A. The second synchronizer 23 connects the first speed drive gear 20A to the second intermediate shaft 10 by moving the sleeve to the left side in FIG. 4, and the first speed gear pair 20 is connected to the second intermediate shaft 10. Torque is transmitted to and from the output shaft 16. On the other hand, the third speed drive gear 19A is connected to the second intermediate shaft 10 by moving the sleeve to the right in FIG. 4, and the third speed gear pair 19 is connected to the second intermediate shaft 10 and the output shaft 16. Torque is transmitted between the two.

  Further, on the first intermediate shaft 8, a third synchronizer (hereinafter referred to as a third synchronizer) 24 is provided between the second speed drive gear 18A and the fourth speed drive gear 17A. The third synchronizer 24 moves the sleeve to the left side in FIG. 4 to connect the second speed drive gear 18A to the first intermediate shaft 8, and the second speed gear pair 18 is connected to the first intermediate shaft 8. Torque is transmitted to and from the output shaft 16. On the contrary, the fourth speed drive gear 17A is connected to the first intermediate shaft 8 by moving the sleeve to the right in FIG. 4, and the fourth speed gear pair 17 is connected to the first intermediate shaft 8 and the output shaft 16. Torque is transmitted between the two.

  Further, on the motor shaft 11 on the second pump motor 13 side, a reverse synchronizer (hereinafter referred to as R synchro) 25 is provided at a position adjacent to the shaft end of the second intermediate shaft 10. The R synchro 25 connects the motor shaft 11 and the second intermediate shaft 10, that is, the sun gear 4S and the carrier 4C in the second planetary gear mechanism 4 by moving the sleeve to the right in FIG. The entire planetary gear mechanism 4 is configured to rotate integrally.

  Each of the synchros 22, 23, 24, and 25 can be configured to be switched by manual operation, but can be configured to perform so-called automatic control instead. In that case, for example, an appropriate actuator (not shown) for moving the above-described sleeve in the axial direction may be provided, and the actuator may be electrically controlled.

  As described above, the transmission TM shown in FIG. 4 transmits the torque output from the power source 1 to the output shaft 16 via any one of the intermediate shafts 8 and 10 or the motor shafts 9 and 11. It is configured. A differential 27 is connected to the output shaft 16 through a transmission means 26 such as a gear mechanism or a winding transmission mechanism such as a chain, and power is output to the left and right axles 28 from here.

  Further, a sensor for detecting the operating state of the transmission TM is provided. Specifically, the input rotational speed sensor 29 for detecting the rotational speed of the input member 2 or the counter drive gear 5 integrated therewith, the output rotational speed sensor 30 for detecting the rotational speed of the axle 28, and the first pump motor 12. A rotation speed sensor 31 for detecting the rotation speed of the second pump motor 13 and the rotation speed sensor 32 for detecting the rotation speed of the second pump motor 13 are provided.

  Next, a fluid pressure circuit (hydraulic circuit) for controlling the pump motors 12 and 13 will be described. A charge pump (or boost pump) 33 for replenishing fluid (specifically oil) is provided in the above-mentioned closed circuit CC that communicates the pump motors 12 and 13. The charge pump 33 is for compensating for oil shortage due to leakage from the closed circuit CC, and is driven by the power source 1 or a motor (not shown) to pump oil from the oil pan 34. To the closed circuit CC.

  Accordingly, the discharge port of the charge pump 33 communicates with the oil passage 14 and the oil passage 15 in the closed circuit CC via the check valves 35 and 36, respectively. In addition, these check valves 35 and 36 are comprised so that it may open in the discharge direction from the charge pump 33, and may close in the opposite direction. Further, a relief valve 37 for adjusting the discharge pressure of the charge pump 33 is communicated with the discharge port of the charge pump 33. The relief valve 37 is a valve (for example, a solenoid valve) that can electrically control the relief pressure, and is opened when a pressure higher than the sum of the elastic force of the spring and the pilot pressure or the pressing force of the solenoid is applied. The oil is discharged to the oil pan 34. Therefore, the discharge pressure of the charge pump 33 is set to a pressure corresponding to the pilot pressure.

  A relief valve 38 is provided between the suction port 12 </ b> S of the first pump motor 12 and the oil passage 15. Specifically, a relief valve 38 is provided in parallel with the first pump motor 12 so as to communicate the oil passages 14 and 15. The relief valve 38 is a valve (for example, a solenoid valve) capable of electrically controlling the relief pressure, and pressure oil is supplied from the suction port 12S of the first pump motor 12 or the suction port 13S of the second pump motor 13. When discharging, the discharge pressure is maintained at a preset pressure. A relief valve 39 is provided between the discharge port 13 </ b> D of the second pump motor 13 and the oil passage 14. Specifically, a relief valve 39 is provided in parallel with the second pump motor 13 so as to communicate the oil passages 14 and 15. The relief valve 39 is a valve (for example, a solenoid valve) that can electrically control the relief pressure, and pressure oil is supplied from the discharge port 12D of the first pump motor 12 or the discharge port 13D of the second pump motor 13. When discharging, the discharge pressure is maintained at a preset pressure.

  An accumulator 40 is provided for accumulating pressure oil and supplying the accumulated pressure oil to the first pump motor 12 or the second pump motor 13. The accumulator 40 is a pressure accumulator that stores the hydraulic pressure generated by any one of the pump motors 12 and 13, and is selectively connected to any one of the oil passages 14 and 15 that have a relatively high pressure by a switching valve 41 described later. It is comprised so that it may be connected to.

  The switching valve 41 includes a port to which the oil passages 14A and 15A branched from the oil passages 14 and 15 are connected, and a port to which the accumulator 40 is communicated, and a closed position in which all these ports are closed, A first switching position for connecting the accumulator 40 to the oil passage 15 that connects the discharge ports 12D and 13D, and a second that connects the accumulator 40 to the oil passage 14 that connects the suction ports 12S and 13S. A valve element (not shown) is selectively moved to the switching position. The switching operation of the valve element is configured to be electrically controlled by energizing a solenoid or the like.

  Each of the oil passages 14A and 15A branched from the oil passages 14 and 15 has check valves 42 and 43 that open when pressure oil flows toward the switching valve 41 and close in the opposite direction. It is intervened. In addition, a flow rate control valve 44 that controls the flow rate of the pressure oil to the accumulator 40 is provided between the switching valve 41 and the accumulator 40. The flow rate control valve 44 is preferably configured to be able to electrically control the flow rate. Specifically, an electromagnetic proportional flow rate control valve can be used. A hydraulic sensor 45 that detects the pressure in the oil passage 14, a hydraulic sensor 46 that detects the hydraulic pressure in the oil passage 15, and a hydraulic sensor 47 that detects the hydraulic pressure in the accumulator 40 are provided.

  In order to use the hydraulic pressure stored in the accumulator 40, an oil passage 49 with an on-off valve 48 is connected to the accumulator 40, and lubrication and control for switching the synchros 22, 23, 24, 25 are performed. As necessary, the on-off valve 48 is selectively opened to supply the hydraulic pressure of the accumulator 40 to a predetermined location.

  The extrusion volume of each pump motor 12, 13 and the operation of each synchro 22, 23, 24, 25, the relief valves 37, 38, the switching valve 44, and the opening of each flow control valve 41 are electrically controlled. An electronic control unit (ECU) 50 for this purpose is provided. This electronic control unit 50 is configured mainly with a microcomputer, and receives the number of rotations of a predetermined rotating member and other detection signals, and those input signals and information stored in advance. In addition, the calculation is performed based on the program, and the command signal is output according to the calculation result.

  Next, the operation of the transmission TM described above will be described. First, the shift control by the transmission TM will be described. In the above-described transmission TM, the shift control can be performed in the same manner as the transmission described in Patent Document 2 described above. FIG. 5 is a chart collectively showing the operation states of the pump motors (PM1, PM2) 12, 13 and the synchros 22, 23, 24, 25 when setting the respective gear positions. “OFF” for each of the pump motors 12 and 13 makes the pump capacity (extrusion volume) substantially zero, does not generate pressure oil even when its output shaft is rotated, and is supplied with hydraulic pressure. Indicates a state where the output shaft does not rotate (free), and “LOCK” indicates a state where the rotation of the rotor is stopped. Furthermore, “hydraulic pressure generation” indicates a state in which the pump capacity (extrusion volume) is made larger than substantially zero and the pressure oil is discharged, and thus the corresponding pump motors 12 and 13 function as pumps. “Hydraulic pressure recovery” indicates a state in which pressure oil discharged from one pump motor 13 (or 12) is supplied and functions as a motor, and therefore the corresponding pump motor 13 (or 12) has a shaft torque. The generated torque is transmitted to the corresponding motor shafts 9 and 11 and the intermediate shafts 8 and 10.

  The “right” and “left” for each synchro 22, 23, 24, 25 indicate the position of the sleeve in each synchro 22, 23, 24, 25 in FIG. 4, and the parentheses are downshifted. The stand-by state, the brackets indicate the stand-by state for upshifting, and “◯” reduces drag by setting the corresponding synchro 22, 23, 24, 25 to the OFF state (neutral position). “●” indicates that the corresponding synchro 22, 23, 24, 25 is set to the OFF state (neutral position) and is in the neutral state.

  When the neutral (N) state is set by selecting a neutral position with a shift device (not shown), the pump motors 12 and 13 are set to the “OFF” state, and the synchros 22, 23, 24, 25 sleeves are set in the center position. Therefore, none of the gear pairs 17, 18, 19, 20, 21 is in a neutral state that is not connected to the output shaft 16. That is, the pump motors 12 and 13 are controlled so that the pump capacity (extrusion volume) becomes substantially zero, and as a result, a so-called idling state is established, so that the ring gears 3R and 4R of the planetary gear mechanisms 3 and 4 are obtained. Even if torque is transmitted from the power source 1, no reaction force acts on the sun gears 3S, 4S, so that torque is not transmitted to the intermediate shafts 8, 10 connected to the carriers 3C, 4C as output elements.

  When the shift position is switched to a travel position such as a drive position, the sleeve of the first sync 22 is moved to the left in FIG. 4 and the sleeve of the second sync 23 is moved to the left in FIG. Accordingly, the start driven gear 21B is connected to the output shaft 16 to connect the first pump motor 12 and the output shaft 16, and the first speed drive gear 20A is connected to the second intermediate shaft 10 to thereby provide the second planetary gear mechanism. 4 is the output element 4 and the output shaft 16 is coupled. That is, the first speed that is the fixed gear ratio is set. At the same time, the extrusion volume of each pump motor 12, 13 is controlled to be larger than zero.

  Therefore, the second pump motor 13 is driven by the power of the power source 1 divided by the second planetary gear mechanism 4 to function as a pump, and the reaction torque generated by generating hydraulic pressure is applied to the motor shaft 11 and the sun gear 4S. give. This is described as “hydraulic pressure generation” in FIG. Therefore, the torque is transmitted to the carrier 4C by the differential action of the second planetary gear mechanism 4, and the torque is transmitted to the output shaft 16 via the first speed gear pair 20. On the other hand, since the hydraulic pressure generated by the second pump motor 13 is discharged from the suction port 13S and supplied to the suction port 12S of the first pump motor 12 through the oil passage 14, the first pump motor 12 functions as a motor. And rotate forward. Therefore, the pressure in the oil passage 14 is relatively higher than the pressure in the oil passage 15, and in this case, the oil passage 14 corresponds to the high-pressure passage of the present invention. This state is described as “hydraulic pressure recovery” in FIG. In this way, the power transmitted to the first pump motor 12 is transmitted to the output shaft 16 via the starting gear pair 21. Therefore, in the driving state from the start to the first speed, both so-called mechanical power transmission via the second planetary gear mechanism 4 and power transmission via the hydraulic pressure are generated, and the combined power of these powers is generated. Appears on the output shaft 16. Further, the gear ratio in this process becomes a value larger than the first speed which is a fixed gear ratio, and the gear ratio changes continuously, that is, steplessly.

  When the rotational speed of the power source 1 and the vehicle speed change in this way to the first speed gear ratio, the first pump motor 12 is controlled to be in the OFF state, and the pushing volume is set to zero. As a result, since the closed circuit CC is closed by the first pump motor 12, the second pump motor 13 cannot perform suction and discharge of pressure oil, and the second pump motor 13 is locked. That is, the rotation is stopped. As a result, the sun gear 4S of the second planetary gear mechanism 4 is fixed, and the first planetary gear mechanism 3 is not involved in the transmission of power to the output shaft 16, so that the power output from the power source 1 is the second planetary gear. It is transmitted to the output shaft 16 via the mechanism 4 and the first speed gear pair 20. That is, a fixed gear ratio determined by the gear ratio of the first speed gear pair 20 is set.

  In the case of upshifting to the second speed, which is a fixed gear ratio, the sleeve of the third sync 24 is moved to the left side in FIG. 4 to connect the second speed drive gear 18A to the first intermediate shaft 8. When the sleeve of the third synchro 24 is engaged with the second speed drive gear 18A, the hydraulic pressure of the charge pump 33 is supplied to the first pump motor 12 and rotated to thereby rotate the third synchro 24. You may perform synchronous control which makes the rotation speed of a sleeve and the rotation speed of the 2nd speed drive gear 18A correspond.

  In this state, the R synchro 25 is set to the neutral state, and the extrusion volume of the first pump motor 12 is gradually increased toward the maximum. In the upshift standby state to the second speed, the first pump motor 12 is rotating in the reverse direction, and when its extrusion volume is gradually increased, it functions as a pump and generates hydraulic pressure ("hydraulic pressure generation" in FIG. At the same time, the reaction torque associated therewith appears on the motor shaft 9. As a result, transmission of power through the first planetary gear mechanism 3 and the second speed gear pair 18 is gradually performed. Further, the hydraulic pressure generated by the first pump motor 12 is supplied to the second pump motor 13 via the oil passage 14 and functions as a motor (denoted as “hydraulic pressure recovery” in FIG. 5). Power is transmitted through the motor 13, the second planetary gear mechanism 4, and the first speed gear pair 20. Therefore, also in this case, the oil passage 14 becomes a high-pressure passage. Therefore, the speed ratio in the process of shifting from the first speed to the second speed is a value between the speed ratio of the first speed and the speed ratio of the second speed, and is a continuously changing speed ratio. . That is, a continuously variable transmission state in which the gear ratio continuously changes is obtained. This is the same during the period from the start to the speed ratio of the first speed and between the fixed speed ratios. Therefore, the power transmission device described above can function as a continuously variable transmission. .

  When the extrusion volume of the second pump motor 13 becomes almost zero and the extrusion volume of the first pump motor 12 becomes almost maximum and the rotation stops or is almost stopped, the second pump motor 13 is turned off. Set to state. Accordingly, since the first pump motor 12 is locked and the sun gear 3S of the first planetary gear mechanism 3 is fixed, the power input to the ring gear 3R passes from the carrier 3C to the second speed drive gear 18A via the intermediate shaft 8. Is output. On the other hand, the second pump motor 13 is in the OFF state, and the R synchro 25 and the second synchro 23 arranged coaxially with the second pump motor 13 are in the OFF state and the sleeve is in the neutral position. The motor 13 and the second planetary gear mechanism 4 are not involved in power transmission. Accordingly, the second speed, which is a fixed gear ratio determined by the gear ratio of the second speed gear pair 18, is set.

  Thereafter, in the same manner, for the third speed, the sleeve of the second synchro 23 is moved to the right side in FIG. 4 to connect the third speed drive gear 19A to the second intermediate shaft 10, and the other synchros 22 and 24 are turned off. Put it in a state. Accordingly, the power is transmitted to the output shaft 16 via the third speed gear pair 19, and the third speed, which is a fixed gear ratio, is set. For the fourth speed, the sleeve of the third synchro 24 is moved to the right in FIG. 4 to connect the fourth speed drive gear 17A to the first intermediate shaft 8, and the other synchros 23 and 25 are turned off. Therefore, power is transmitted to the output shaft 16 via the fourth speed gear pair 17 and the fourth speed, which is a fixed gear ratio, is set.

  Further, the reverse gear will be described. When the reverse range is selected by a shift device (not shown), the sleeve of the first sync 22 is moved to the left side of FIG. 4, and the sleeve of the R sync 25 is moved as shown in FIG. The other syncs 23 and 24 are set to the OFF state. Therefore, when the second intermediate shaft 10 and the motor shaft 11 are connected by the R synchro 25, the sun gear 4S of the second planetary gear mechanism 4 and the carrier 4C are connected, and the entire second planetary gear mechanism 4 is substantially the same. Integrated. Further, the start driven gear 21 </ b> B is connected to the output shaft 16.

  Therefore, the power transmitted from the power source 1 to the second planetary gear mechanism 4 is transmitted to the second pump motor 13 as it is, and this is driven, and the second pump motor 13 generates hydraulic pressure. Since the second synchro 23 is in the OFF state, power is not transmitted from the second planetary gear mechanism 4 or the second intermediate shaft 10 to the output shaft 16. On the other hand, the extrusion volume of the first pump motor 12 is controlled to a volume larger than zero, for example, the maximum volume. As a result, the first pump motor 12 is driven by the hydraulic pressure supplied from the second pump motor 13 through the oil passage 14. And outputs torque to the motor shaft 9. Therefore, the oil passage 14 is a high-pressure passage in the present invention. In that case, since the hydraulic pressure is supplied to the first pump motor 12 from the discharge port 12D via the oil passage 14, the first pump motor 12 rotates in the reverse direction. Then, the torque is transmitted to the output shaft 16 via the starting gear pair 21, so that a reverse state is established. That is, in the reverse speed, power is transmitted via hydraulic pressure, and in FIG. 5, this is indicated as “hydraulic recovery” for the first pump motor 12 and “hydraulic pressure generation” for the second pump motor 13.

  As described above, in the transmission TM that is the subject of the present invention, the four forward speeds of the first speed to the fourth speed are set as so-called fixed speed ratios (fixed speed stages) that can be set by transmitting torque without using fluid. And one reverse speed can be set, and in the shift between these fixed speed ratios, the speed ratio can be continuously changed, that is, a continuously variable speed can be achieved. In a so-called driving state in which power is transmitted from the power source 1 to the output shaft 16, pressure oil is supplied between the pump motors 12 and 13 via the oil passage 14. On the other hand, when power is transmitted from the output shaft 16 side to the power source 1, such as when the vehicle equipped with the transmission TM is decelerating, it functions as a motor in the drive state. Since the pump motor 12 (or 13) is rotated by torque transmitted from the output shaft 16 side, the pump motor 13 (or 12) that functions as a pump, generates hydraulic pressure, and functions as a pump is used as the motor. Functions as a torque output. In such a deceleration state or driven state, the pressure in the oil passage 15 becomes high, which is opposite to the driving state described above, and this corresponds to the high-pressure passage in the present invention. The control device according to the present invention is configured to improve the energy efficiency by collecting the hydraulic pressure generated in this manner in the accumulator 40. The pressure accumulation control will be described next.

  In the drive state described above, hydraulic pressure is supplied from one pump motor 12 (or 13) to the other pump motor 13 (or 12) via the oil passage 14, and discharged from the pump motor 13 (or 12) functioning as a motor. The pressurized oil thus supplied is supplied to a pump motor 12 (or 13) functioning as a pump via an oil passage 15 which is a so-called low pressure passage in this case. In this case, the pressure oil corresponding to the inevitable oil leakage is supplied from the charge pump 33, but basically the amount of the pressure oil in the closed circuit CC does not change, and the pump motors 12 and 13 are excessive. The desired gear ratio for supplying pressure oil without a shortage is set, and the drive torque is obtained. Therefore, the switching valve 41 is controlled to the closed position and shuts off the accumulator 40 from the closed circuit CC.

  On the other hand, in the driven state (braking state), the hydraulic pressure generated by the pump motor 13 (or 12) functioning as a pump is supplied to the other pump motor 12 (or 13) via the oil passage 15, and this is the motor. However, since the power output from the pump motor 12 (or 13) is not particularly consumed, the pressure oil in the oil passage 15 is increased. Therefore, hydraulic pressure is supplied from the oil passage 15 to the accumulator 40, and so-called surplus power at the time of driving is recovered in the form of hydraulic pressure.

  FIG. 1 is a flowchart for explaining an example of pressure accumulation control (energy regeneration control) executed by the control device of the present invention. First, the throttle opening θ and the engine speed used as the power source 1 are illustrated. Various signals such as Ne and a brake signal are read (step S1). The throttle opening θ is read as a signal indicating the required drive amount or the required state of the vehicle. Therefore, when vehicle speed maintenance control such as cruise control is being executed, a request from the control system is obtained. A signal may be employed. Moreover, the signal from the brake switch normally provided in the vehicle can be utilized for a brake signal.

  Based on these read signals, it is determined whether the vehicle is in a braking state (step S2). Here, the braking state is a so-called power source braking state (engine braking state) in which the power source 1 is driven and a so-called drag torque accompanying the power loss is used as a braking force, and braking by the driver performing a braking operation. Includes both states. If the determination in step S2 is affirmative due to the braking state, the valve body of the switching valve 41 described above is moved to the right side of FIG. Then, the oil passage 15 serving as the high-pressure passage is connected to the accumulator 40 serving as the pressure accumulator (step S3). In addition, since it is a drive state when it is negatively determined by step S2, if the pressure accumulation in a drive state is performed, the switching valve 41 will be operated to a 2nd switching position (step S4). That is, the valve body is moved to the left side of FIG.

  When accumulating pressure in the driven state by moving the switching valve 41 to the right in FIG. 4, the pressure oil for the accumulator 40 simultaneously with the switching operation of the switching valve 41, or after that, or prior to the switching of the switching valve 41. Is started (step S5). That is, by controlling the electromagnetic proportional flow control valve 44 described above, the amount of pressure oil supplied to the accumulator 40 is gradually increased, and pressure accumulation is started. At the same time, the control of the extrusion volume of each pump motor 12, 13 is started (step S6). This extrusion volume control is control for maintaining the transmission ratio and the pressure of the accumulator 40 at target values, and each extrusion volume is calculated as follows.

ここで、ρは各遊星歯車機構３，４におけるギヤ比（サンギヤの歯数とリングギヤの歯数との比）、ｑpm1は第１ポンプモータ１２の押出容積、ｑpm2は第２ポンプモータ１３の押出容積、κ2は第２速用ギヤ対１８のギヤ比、κ3は第３速用ギヤ対１９のギヤ比である。この（１）式を書き換えると、（２）式のようになる。

In the transmission TM that is the subject of the present invention, the transmission ratio other than the fixed transmission ratio among the transmission ratios higher than the first speed, which is the fixed transmission ratio, transmits torque using two gear pairs for transmission. It is set by doing. Therefore, the gear ratio γ is expressed by the equation (1) when the gear ratio between the second speed and the third speed is taken as an example.

Here, ρ is a gear ratio (ratio between the number of teeth of the sun gear and the number of teeth of the ring gear) in each planetary gear mechanism 3, 4, qpm 1 is an extrusion volume of the first pump motor 12, and qpm 2 is an extrusion of the second pump motor 13. Volume, κ2 is the gear ratio of the second speed gear pair 18, and κ3 is the gear ratio of the third speed gear pair 19. Rewriting equation (1) yields equation (2).

  As can be seen from the equation (2), the speed ratio γ is a function of the ratio of the extrusion volumes qpm1 and qpm2 of the pump motors 12 and 13 (hereinafter referred to as the extrusion volume ratio). By doing so, the gear ratio γ can be made to coincide with the target gear ratio, or can be changed following the change of the target gear ratio.

ここで、Ｎｅは動力源１であるエンジンの回転数である。 On the other hand, the rotational speed Npm2 of the second pump motor 13 is expressed by the formula (3), and the rotational speed Npm1 of the first pump motor 12 is expressed by the formula (4).

Here, Ne is the rotational speed of the engine that is the power source 1.

As described above, in the normal shift control state in which the hydraulic pressure is not recovered by the accumulator 40, the pump motors 12 and 13 communicate with each other through the closed circuit CC, so that the pump motors functioning as pumps (described here). In this example, the flow rate discharged from the first pump motor 12) and the flow rate flowing into the pump motor functioning as the motor (second pump motor 13 in the example described here) are expressed by the following equation (5). It becomes equal as shown by.

On the other hand, when accumulator 40 accumulates pressure in the driven state in which the speed ratio between the second speed that is the fixed speed ratio and the third speed that is the fixed speed ratio is set, the first pump Since the motor 12 is driven by the torque transmitted from the output shaft 16 side and functions as a pump, a part of the pressure oil discharged from the first pump motor 12 flows into the accumulator 40. Therefore, the amount of pressure oil flowing into the second pump motor 13 that functions as a motor in this driven state is reduced by the amount QA flowing into the accumulator 40. If this is expressed by an equation, equation (6) is obtained.

Therefore, the extrusion volume qpm2 ′ of the second pump motor 13 at the time of accumulating pressure oil supplied to the accumulator 40 is expressed by the equation (7).

Substituting this into the above-described equation (2) yields equation (8).

  That is, the transmission ratio can be maintained at the target transmission ratio by controlling the extrusion volume so that the aforementioned extrusion volume ratio is constant before and after the start of pressure accumulation. In the example described here, since the second pump motor 13 functions as a motor, the gear ratio γ is maintained by changing the extrusion volume qpm2.

  In the control example shown in FIG. 1, in order to maintain the speed ratio γ at a predetermined value before and after the start of the pressure accumulation control, first, the requested drive amount and the vehicle speed V are read (step S7). The requested amount of driving may be the throttle opening θ or the accelerator opening. Then, the target gear ratio γ is calculated based on the required drive amount (specifically, the throttle opening θ) and the vehicle speed V (step S8). This can be obtained by a conventional method, and more specifically, a rotation speed at which the required output obtained from the drive request amount and the vehicle speed V can be achieved with optimum fuel consumption is obtained from the map, and the rotation speed is calculated. A target speed ratio γ to be achieved is obtained. Next, an extrusion volume ratio for setting the target speed ratio γ is calculated (step S9). This can be performed using the above-described equation (1) or (2).

  On the other hand, the target speed ratio γ obtained in step S8 and the engine speed Ne are read (step S10), and these are substituted into the above-described equations (3) and (4) to obtain the respective pump motors 12. , 13 target rotation speeds Npm1, Npm2 are obtained (step S11). Then, the pushing volume qpm1 of the pump motor (in the example described here, the first pump motor 12) functioning as a pump is obtained by using the above-described formulas (2) and (5), and the accumulator 40 is supplied to the accumulator 40. The inflow amount QA of the pressure oil is obtained (step S12). This inflow amount QA is a flow rate set by the flow rate control valve 44, and is a predetermined amount in design within the range of the flow rate that can be replenished by the charge pump 33 described above. Thus, since the numerical values on the right side of the equation (7) are determined, the target values of the extrusion volumes of the pump motors 12 and 13 are maintained so as to maintain the extrusion volume ratio obtained in the above-described step S9 even if accumulator 40 accumulates pressure. qpm1 and qpm2 ′ are obtained (step S13).

ここで、Ｔｄは被駆動状態で動力源１の出力部に現れる引き摺りトルクである。なお、動力源１が動力を出力して車両が走行している場合には、その出力トルクすなわち前記入力部材２に入力されるトルクをＴinとすると、目標圧力Ｐ、各押出容積ｑpm1，ｑpm2、入力トルクＴinとの関係は、（１０）式で表すようになる。

Further, the target pressure P in the accumulator 40, that is, the pressure P to be stored in the accumulator 40, and the output torque Tout of the power source 1 are read (step S14). This is to obtain the extrusion volume for accumulating at the target pressure P. That is, the target pressure P, which is a pressure that can be generated in the high-pressure flow path, the torque appearing at the output portion of the power source 1 and the extrusion volumes qpm1, qpm2 are in a relationship represented by equation (9).

Here, Td is the drag torque that appears at the output portion of the power source 1 in the driven state. When the power source 1 outputs power and the vehicle is traveling, assuming that the output torque, that is, the torque input to the input member 2, is Tin, the target pressure P, the extrusion volumes qpm1, qpm2, The relationship with the input torque Tin is expressed by equation (10).

  Therefore, after obtaining the extrusion volumes qpm1, qpm2 ′ for maintaining the speed ratio γ in step S13, the extrusion for obtaining the target pressure P while maintaining the speed ratio γ using the target pressure P and the drag torque Td. Volumes qpm1 ′ and qpm2 ″ are obtained (step S15). In step S6 described above, the pump motors 12 and 13 are controlled so as to set the extrusion volumes thus obtained. The control is the same as that normally performed in variable displacement pump motors such as radial piston pumps, axle pumps, and swash plate pumps, and can be performed by electrically controlling the actuators attached to each pump. it can.

  As described above, the hydraulic pressure can be recovered from the oil passage 15, which is a high-pressure passage, to the accumulator 40 in a driven state such as when the vehicle is decelerated. In this case, the extrusion volumes qpm1 and qpm2 are controlled so that the ratio is constant or corresponding to the target gear ratio γ, so that the gear ratio changes as the hydraulic pressure (or surplus power) is recovered. Thus, it is possible to prevent or suppress a situation such as a deviation from the target value.

  Even during the recovery of the hydraulic pressure (or energy), the vehicle running state (operating state) such as the throttle opening θ, the rotational speed of the power source 1 (engine rotational speed Ne), and the brake signal is read ( Step S16), it is determined whether or not the braking state of the vehicle continues based on these read data (step S17). This is the same determination as in step S2 described above. If a positive determination is made in step S17 because the braking state continues, the detected value of the hydraulic sensor 47, that is, the pressure of the accumulator 40, and the detected value of the pressure sensor 46, that is, the oil that is the high-pressure flow path. It is determined whether or not the difference from the pressure in the path 15 is smaller than a predetermined value set in advance as a determination criterion (step S18).

  This step S18 is for determining the end of the pressure accumulation. If the pressure difference is equal to or greater than a predetermined value, the pressure accumulation is continued. On the contrary, if the pressure difference is smaller than the predetermined value. , End the pressure accumulation. That is, if a negative determination is made in step S18, the pressure of the accumulator 40 is sufficiently smaller than the pressure of the oil passage 15, and the flow rate of the pressure oil to the accumulator 40 can be monitored and controlled. The pressure accumulation control is continued after returning.

  If the above-described differential pressure is smaller than the predetermined value as the determination criterion and a positive determination is made in step S18, the control for terminating the pressure recovery control, that is, the pressure accumulation in the accumulator 40 is started. The predetermined value as the determination criterion is set so that the differential pressure does not fall below the pressure difference that can control the flow rate even when the elapsed time until the flow rate QA is made zero is considered. It can be determined by conducting an evaluation. By doing so, it is possible to finish the pressure accumulation control while controlling the pressure or the gear ratio. It should be noted that control for ending pressure accumulation is similarly started when a negative determination is made in step S17 due to, for example, switching from the braking state to the driving state.

  Specifically, the control for ending the pressure accumulation is performed by gradually decreasing the flow rate QA to the accumulator 40 and finally controlling the flow rate control valve 44 so that it becomes zero (step S19). In this case, if the flow rate QA is gradually reduced by gradually reducing the opening degree of the flow rate control valve 44, the value of QA in the above-described equation (7) changes, and accordingly, the extrusion volume qpm2 of the second pump motor 13 is changed. '(Or qpm2 ") is controlled as in step S7 to step S15 described above. Therefore, since the flow rate QA and the extrusion volume are controlled in a coordinated manner, the coordinated control is executed properly. The rate of decrease in the flow rate QA (that is, the decreasing gradient) is set, and the decreasing gradient can be set in advance by an experiment or simulation using an actual machine. The ratio γ is maintained at the target value, and since the flow rate QA is gradually decreased, the transmission ratio γ can be easily maintained, and the shock can be prevented or suppressed in advance. Then, when the flow rate control valve 44 is closed and the flow rate of the pressure oil to the accumulator 40 becomes zero, the valve body of the switching valve 41 is moved to the center (closed position) in FIG. ), The accumulator 40 is shut off from the closed circuit CC, and the pressure accumulation control ends.

  As described above, when the vehicle is decelerated, either one of the pump motors 12 and 13 is driven by the traveling inertia force of the vehicle input from the output shaft 16 side and functions as a pump, and the resulting hydraulic pressure is stored in the accumulator. Thus, the energy can be effectively used. In the control device according to the present invention, although the pressure oil flows out from the closed circuit CC to the accumulator 40 during the recovery control, the pressure oil is replenished by the charge pump 33 and also functions as a motor. , 12, even if the flow rate of the pressure oil decreases, the extrusion volume is controlled so as to maintain the gear ratio γ, so that a shift occurs with the accumulated pressure, or the driving torque changes accordingly. Can be prevented or suppressed.

  Note that the hydraulic pressure stored in the accumulator 40 is used, for example, to assist driving torque when the vehicle starts, or is effectively used for lubrication.

  FIG. 2 is a time chart showing changes in the flow rates Qpm1 and Qpm2 and the extrusion volumes qpm1 and qpm2 in the pump motors 12 and 13 and the pressure oil flow rate QA with respect to the accumulator 40 when the pressure accumulation control shown in FIG. 1 is performed. It is shown by. Accumulation control is started at time t1 when the braking state is detected, and the hydraulic pressure starts to be supplied to the accumulator 40. That is, the flow rate QA for the accumulator 40 gradually increases, and the flow rates at the pump motors 12 and 13 gradually decrease accordingly. In that case, in a state where the speed ratio between the second speed and the third speed, which is the so-called fixed speed ratio (fixed speed) described above, is set, the first pump motor 12 functions as a pump, and its discharge The amount Qpm1 gradually decreases, the second pump motor 13 functions as a motor, and the suction amount Qpm2 decreases more than the discharge amount Qpm1 of the first pump motor 12. Along with this, the extrusion volumes qpm1, qpm2 are controlled to maintain the speed ratio γ at the start of pressure accumulation control and to generate the desired pressure, and gradually decrease. Therefore, in order to obtain the desired pressure P in the closed circuit CC, the extrusion volume qpm1 of the first pump motor 12 changes as indicated by the symbol A in FIG. The change in the extrusion volume qpm2 of the second pump motor 13 is as shown by symbol B in FIG. 2, but the extrusion volume qpm2 of the second pump motor 13 is also changed to maintain the target gear ratio γ. Therefore, the amount of change is as indicated by the symbol C in FIG.

  When the flow rate QA of the pressure oil to the accumulator 40 becomes constant (at time t2), the discharge amount Qpm1 of the first pump motor 12, the inflow amount Qpm2 to the second pump motor 13, and the extrusion volumes qpm1, qpm2 become constant. Thereafter, when the braking state is changed to the driving state, or when the difference between the pressure of the accumulator 40 and the pressure in the high-pressure flow path in the closed circuit CC becomes smaller than a predetermined value (at time t3), the pressure accumulation control is terminated. The flow rate QA for the accumulator 40 is gradually decreased, and accordingly, the flow rates at the pump motors 12 and 13 are gradually increased. Further, the extrusion volumes qpm1 and qpm2 are gradually increased while maintaining the ratio thereof, and the pressure P of the closed circuit CC becomes a desired pressure. Then, at time t4 when the flow rate QA of the pressure oil with respect to the accumulator 40 becomes zero, the pressure accumulation control ends, and as described above, the switching valve 41 is switched to the closed position, and the accumulator 40 is shut off from the closed circuit CC.

  The above-described control example is an example in which one of the pump motors 12 and 13 is driven by the traveling inertia force during braking, and the hydraulic pressure generated is recovered. In the driving state in which the vehicle is traveling with the power output from the power source 1. Alternatively, the energy may be collected by accumulating in the accumulator 40. This is because the power source 1 may output more power than is necessary for traveling. A control example in that case is shown in a flowchart in FIG.

  The functions of the pump motors 12 and 13 in the driving state are opposite to the functions in the driven state (braking state) described above. For example, the speed ratio of the second speed and the speed ratio of the third speed which are fixed speed ratios. The second pump motor 13 functions as a pump by rotating with power transmitted from a power source, and the relatively high pressure discharged from the second pump motor 13 is set. Hydraulic pressure is supplied to the first pump motor 12 via the oil passage 14, and this functions as a motor. Therefore, the pressure accumulation control in the driven state is only a change accompanying the replacement of the functions of the pump motors 12 and 13 with respect to the control in the driven state. Therefore, the control shown in FIG. 3 will mainly be explained with respect to the parts different from the control shown in FIG. 1, and the same parts as those shown in FIG. The description is omitted.

  When accumulating in the driving state, it is determined negative in step S2 because it is not in the braking state, and accordingly, it is determined whether or not the residual pressure (or oil amount) of the accumulator 40 is equal to or greater than a predetermined amount ( Step S21). If the residual pressure (or oil amount) is greater than or equal to the specified amount and affirmative determination is made in step S21, there is no need to perform pressure accumulation, or there is no room for the accumulator 40 to perform pressure accumulation. Return to S2. On the other hand, if it is determined affirmatively in step S21 because the residual pressure (or oil amount) is less than the specified amount, the process proceeds to step S4, and the valve body of the switching valve 41 is set as shown in FIG. The accumulator 40 is moved to the left side to communicate with the oil passage 14 which is a high-pressure oil passage in this case. Thereafter, the flow rate control valve 44 is gradually opened to gradually increase the flow rate to the accumulator 40 (step S5), and the extrusion volumes qpm1, qpm2 of the pump motors 12, 13 are controlled (step S6).

  In this case, since the first pump motor 12 functions as a motor in a driving state in which the speed ratio between the second speed ratio and the third speed ratio is set, the accumulator 40 accumulates pressure. Since the inflow amount to the first pump motor 12 decreases, the extrusion volume qpm1 of the first pump motor 12 is controlled in order to prevent the change in the gear ratio γ. That is, the extrusion volume qpm1 'of the first pump motor 12 for maintaining the speed ratio γ is calculated (step S23). This can be obtained by the above-described equation (7), which is obtained by replacing qpm2 'with qpm1', Qpm1 with Qpm2, and Npm2 with Npm1. Further, the extrusion volumes qpm1 ″ and qpm1 ′ for obtaining the target pressure P can be obtained using the above-described equation (10).

  Therefore, even in the driving state, energy can be recovered by accumulating pressure in the accumulator 40 without changing the speed ratio γ. Further, similarly to the pressure accumulation in the driven state described above, the accumulator 40 can accumulate pressure at a preset target pressure, so that stable oil pressure can be obtained when the accumulated oil pressure is used.

  The conditions for ending the pressure accumulation control performed in the driving state are that the vehicle is in a braking state and that the pressure difference between the accumulator 40 and the high-pressure oil path is lower than a predetermined value. Therefore, it is determined whether or not the braking state has been entered after the control of the extrusion volumes qpm1, qpm2 is started with the start of pressure accumulation (step S17). Further, in the driving state in which the gear ratio between the second speed gear ratio and the third speed gear ratio is set, the oil passage 14 is a high pressure passage, so that the determination of the end of pressure accumulation is performed. As the pressure difference, a difference between the pressure in the oil passage 14 and the pressure in the accumulator 40 is adopted, and it is determined whether or not this is smaller than a predetermined value (step S18). Other controls are the same as in the example shown in FIG.

  Therefore, pressure accumulation can be performed without changing the gear ratio even in the driving state. Further, since the pressure accumulation is performed only when the residual pressure of the accumulator 40 or the amount of oil is reduced, it is possible to avoid or suppress situations such as wasteful consumption of power or deterioration of fuel efficiency due to that. can do.

  Here, the relationship between each of the specific examples described above and the present invention will be briefly described. The functional means for executing step S8 described above corresponds to the target transmission calculating means of the present invention, and executes steps S6 to S15. The functional means corresponds to the extrusion volume control means in the present invention, the functional means for executing step S14 corresponds to the target pressure setting means of the present invention, and the functional means for executing steps S17 and S18 of the present invention. The functional means that corresponds to the pressure accumulation end means and further executes step S21 corresponds to the recovery control means of the present invention.

  The present invention is not limited to the specific examples described above, and pressure accumulation is performed in a state where a speed ratio other than the speed ratio between the second speed ratio and the third speed ratio is set. It can also be applied to. In addition to the configuration using the differential mechanism as the power split mechanism having the same gear ratio, a differential mechanism having a different gear ratio may be used as the power split mechanism. Further, in the above specific example, a configuration using two sets of power transmission systems including a differential mechanism, a pump motor, and an intermediate shaft is shown. However, the transmission targeted by the present invention includes three or more sets of power transmission systems. You may comprise using. In addition to the configuration in which the pressure accumulation or energy regeneration is performed in both the driven state and the driving state, the pressure accumulation may be performed only in either the driven state or the driving state. The switching valve in the invention may be any valve that can selectively communicate the high-pressure channel and the accumulator.

It is a flowchart for demonstrating the example of control performed with the control apparatus which concerns on this invention. It is a time chart which shows the change of the flow volume of each pump motor at the time of performing control shown in FIG. 1, and the extrusion volume and the flow volume to an accumulator. It is a flowchart for demonstrating the other example of control performed with the control apparatus which concerns on this invention. It is a skeleton figure which shows typically an example of the transmission made into object by this invention. FIG. 5 is a chart collectively showing operation states of pump motors and synchros when setting gear ratios in the transmission shown in FIG. 4.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Power source (E / G), 2 ... Input member, 3 ... 1st planetary gear mechanism, 4 ... 2nd planetary gear mechanism, 8 ... 1st intermediate shaft, 10 ... 2nd intermediate shaft, 12 ... 1st pump Motor, 13 ... 2nd pump motor, 14, 15 ... Oil passage, 16 ... Output shaft (output member), 17, 18, 19, 20 ... Gear pair (transmission mechanism), 22, 23, 24, 25 ... Synchronizer (Switching mechanism), 33 ... charge pump, 40 ... accumulator (accumulator), 41 ... switching valve, 50 ... electronic control unit (ECU), CC ... closed circuit, TM ... transmission, Ve ... vehicle.

Claims (9)

At least two differential mechanisms to which variable displacement pump motors that selectively provide reaction torque and drive torque are respectively connected are connected in parallel to the power source, and the differential mechanism and the output member A variable displacement pump motor type transmission in which a transmission mechanism is provided between the variable displacement pump motors, the variable displacement pump motors communicate with each other via a closed circuit, and a charge pump for supplying fluid to the closed circuit is provided. In the control device of
A pressure accumulator communicated via a switching valve having an opening / closing function to a high pressure flow path for supplying a relatively high pressure fluid discharged from one of the variable displacement pump motors to the other variable displacement pump motor; ,
Target gear ratio calculating means for obtaining a target gear ratio to be set;
A value for setting the target speed ratio obtained by the target speed ratio calculating means for the ratio between the extrusion volumes of the variable displacement pump motors when the pressure fluid is supplied from the high pressure flow path to the pressure accumulator to accumulate pressure. And a control device for the variable displacement pump motor type transmission. Further comprising target pressure setting means for setting a target pressure to be stored in the pressure accumulator,
The extrusion volume control means includes means for controlling the sum of the extrusion volumes of the variable displacement pump motors to be the target pressure set by the target pressure setting means while maintaining the ratio. 2. The control apparatus for a variable displacement pump motor type transmission according to claim 1, wherein the control apparatus is a variable displacement pump motor type transmission.   The pressure accumulation end means for ending pressure accumulation in the pressure accumulator when the pressure difference between the pressure in the high pressure flow path and the pressure in the pressure accumulator is lowered to a predetermined value. 3. A control apparatus for a variable displacement pump motor type transmission according to 1 or 2.   The extrusion volume control means changes the extrusion volume of a variable displacement pump motor that functions as a motor by being supplied with pressure fluid from the high-pressure channel as an extrusion volume that is changed to maintain the ratio in accordance with the accumulated pressure. 4. The control apparatus for a variable displacement pump motor type transmission according to claim 1, further comprising means.   The variable displacement capacity according to claim 4, wherein the extrusion volume control means includes means for setting an extrusion volume of a variable displacement pump motor that functions as the motor in accordance with a flow rate of pressure fluid to the pressure accumulator. Type pump motor type transmission control device.   The extrusion volume control means adds the extrusion volume of each variable displacement pump motor to the target pressure, and the output torque of the power source or the drag torque of the power source when the power source is forcibly rotated by an external force. 6. The control apparatus for a variable displacement pump motor type transmission according to any one of claims 2 to 5, further comprising a control unit based on the control.   The pressure accumulation ending means is a means for gradually reducing the flow rate of the pressure fluid to the pressure accumulator while maintaining the ratio and sum of the extrusion volumes of the variable displacement pump motors when the pressure accumulation in the pressure accumulator is terminated. The control apparatus for a variable displacement pump motor type transmission according to any one of claims 3 to 6, further comprising:   With any of the variable displacement pump motors functioning as a pump to generate a relatively high pressure fluid in the high pressure flow path, the pressure of the pressure accumulator or the amount of pressure fluid in the pressure accumulator is previously 8. A recovery control means for operating the switching valve so as to connect the high-pressure flow path to the accumulator when a predetermined value or less is reached. The control apparatus of the variable displacement pump motor type transmission described in 1.   The switching valve is configured to switch between a flow path that is relatively high when the power source is driven to output power and a flow path that is high when the power source is driven to be forcedly rotated by an external force. The control device for a variable displacement pump motor type transmission according to any one of claims 1 to 8, further comprising a valve for communicating the accumulator.

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