JP4415931B2 - Shift control device for automatic transmission for vehicle - Google Patents

Description

  The present invention relates to a shift control device for an automatic transmission for a vehicle that establishes a plurality of gear stages having different gear ratios by selectively engaging a plurality of engagement elements, and more particularly to downing during coasting. The present invention relates to an improvement for reducing a shift shock in a shift.

  Automatic transmissions for vehicles that establish a plurality of gear stages with different gear ratios by selectively engaging a plurality of engagement elements are used in various vehicles. In such an automatic transmission, a technology is known that performs coast down shift when the vehicle decelerates and prepares for depression of the accelerator so that the vehicle can be accelerated with an appropriate driving force when accelerating again from when the vehicle decelerates. . In addition, as in the automatic transmission control device described in Patent Document 1, when performing a coast down shift by re-engaging (clutch-to-clutch) between the disengagement side frictional engagement device and the engagement side frictional engagement device, In order to make the shift characteristics suitable, a technique for providing a shift line for coast down shift different from the shift line in the normal shift has been proposed.

JP 2003-269601 A

  However, in the conventional technique, when the brake operation is performed during the shift, it is difficult to engage the engagement-side engagement element at a predetermined synchronization timing due to a change in deceleration caused by the brake. There is a possibility that a shift shock may occur without ensuring the control accuracy. For this reason, there has been a demand for a shift control device for an automatic transmission for a vehicle that can reduce the shift shock while enabling acceleration with good response when the vehicle is accelerated again from the time of deceleration.

  The present invention has been made against the background of the above circumstances, and an object of the present invention is to provide an automatic transmission for a vehicle that can reduce a speed change shock while enabling acceleration with good response when accelerating again from the time of deceleration of the vehicle. Another object of the present invention is to provide a shift control device for a machine.

In order to solve such a problem, the gist of the present invention is to selectively increase the engagement pressures related to a plurality of engagement elements to selectively engage the plurality of engagement elements. In an automatic transmission for a vehicle that establishes a plurality of gear stages having different gear ratios, an automatic transmission for a vehicle that performs a coast down shift by re-engaging the disengagement-side engagement element and the engagement-side engagement element when the vehicle is decelerated. A speed change control device for determining whether or not there is a driver's intention to decelerate during the coast down shift based on a driver's brake operation and accelerator operation ; When the determination is affirmative, the increase in the engagement pressure of the engagement side engagement element is stopped to prevent the shift from proceeding, and the increase in the engagement pressure is stopped by the shift standby unit. State And a shift progression means for increasing the engagement pressure of the engagement side engagement element again to advance the shift when the determination of the deceleration intention determination means is negative. It is.

In this way, the deceleration intention determination means for determining whether or not the driver intends to decelerate during the coast downshift based on the driver's brake operation and accelerator operation, and the determination of the deceleration intention determination means When affirmatively, the shift standby means for stopping the increase of the engagement pressure of the engagement side engagement element to prevent the shift from proceeding, and the increase of the engagement pressure is stopped by the shift standby means. In this state, when the determination by the deceleration intention determination unit is negative, the shift advancement unit further increases the engagement pressure of the engagement side engagement element to advance the shift. If the person intends to decelerate, i.e., if he / she thinks that he / she intends to shift from the deceleration state to the stop state, the coast-down shift is not allowed to proceed, thereby preventing unnecessary coast-down shift. In addition to being able to prevent a shift shock occurs, if no longer deceleration intention of the driver by advancing the coast downshift, can be accelerated well response when accelerating again during deceleration. That is, it is possible to provide a shift control device for an automatic transmission for a vehicle that can reduce a shift shock while enabling acceleration with good response when the vehicle is accelerated again from the time of deceleration.

  Here, it is preferable that the engagement element is a hydraulic friction engagement device, and the shift standby unit is configured so that when the determination of the deceleration intention determination unit is affirmed, the engagement side hydraulic friction unit is The shift of the engagement side hydraulic pressure supplied to the engagement device is stopped so as not to proceed with the shift, and the shift progress means is configured to perform the engagement when the determination of the deceleration intention determination means is negative. The engagement-side hydraulic pressure supplied to the combined-side hydraulic friction engagement device is increased again to advance the shift. In this way, in a practical vehicle automatic transmission equipped with a plurality of hydraulic friction engagement devices, it is possible to reduce the shift shock while enabling acceleration with good response when accelerating again from the time of deceleration of the vehicle. Can do.

  Preferably, the decelerating intention determination means determines whether the brake operation is released, the accelerator operation is performed, or the release speed of the brake operation amount is equal to or higher than a predetermined value. It is determined that the driver has no intention of deceleration. In this way, it is possible to suitably determine whether or not the driver intends to decelerate.

  Preferably, the vehicle further includes a turning determination unit that determines whether or not the vehicle is in a turning state, and the shift standby unit has the engagement side on condition that the determination of the turning determination unit is denied. The increase of the engagement pressure of the engagement element is stopped to prevent the shift from proceeding. In this way, when the vehicle is turning, there is a high possibility that the vehicle will be accelerated again immediately after the braking operation is performed for turning. It can suppress suitably.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a skeleton diagram illustrating the configuration of an automatic transmission for a vehicle (hereinafter referred to as an automatic transmission) 10 to which the present invention is preferably applied. FIG. It is an action | operation table | surface explaining the action | operation of the engagement element at the time of establishing a step. This automatic transmission 10 includes a first transmission unit mainly composed of a double pinion type first planetary gear unit 12 in a transmission case (hereinafter referred to as a case) 26 as a non-rotating member attached to a vehicle body. 14 and a second transmission unit 20 mainly composed of a single pinion type second planetary gear unit 16 and a double pinion type third planetary gear unit 18 on a common axis, and an input shaft 22 Are rotated and output from the output shaft 24. The input shaft 22 corresponds to an input rotating member, and in this embodiment is the turbine shaft of the torque converter 32 that is rotationally driven by the engine 30 that is a power source for traveling. The output shaft 24 corresponds to an output rotating member, and rotationally drives the left and right drive wheels sequentially through, for example, a differential gear device (final reduction gear) (not shown) and a pair of axles. The automatic transmission 10 is configured substantially symmetrically with respect to its axis, and the lower half of the axis is omitted in the skeleton diagram of FIG.

  The first planetary gear unit 12 includes a sun gear S1, a plurality of pairs of pinion gears P1 that mesh with each other, a carrier CA1 that supports the pinion gears P1 so as to rotate and revolve, and a ring gear R1 that meshes with the sun gear S1 via the pinion gears P1. The carrier CA1 and the ring gear R1 constitute three rotating elements. The carrier CA1 is connected to the input shaft 22 and driven to rotate, and the sun gear S1 is fixed to the case 26 so as not to rotate. The ring gear R <b> 1 functions as an intermediate output member, is rotated at a reduced speed with respect to the input shaft 22, and transmits the rotation to the second transmission unit 20. In the present embodiment, the path for transmitting the rotation of the input shaft 22 to the second transmission unit 20 at the same speed is the first intermediate output path for transmitting the rotation at a predetermined constant gear ratio (= 1.0). The first intermediate output path PA1 includes a direct connection path PA1a that transmits rotation from the input shaft 22 to the second transmission unit 20 without passing through the first planetary gear unit 12, and a first planet from the input shaft 22. There is an indirect path PA1b that transmits the rotation to the second transmission unit 20 via the carrier CA1 of the gear device 12. Further, the transmission ratio from the input shaft 22 to the second transmission unit 20 via the carrier CA1, the pinion gear P1 disposed on the carrier CA1, and the ring gear R1 is larger than the first intermediate output path PA1 (> 1). .0) is a second intermediate output path PA2 that transmits the rotation of the input shaft 22 with a reduced speed (deceleration).

  The second planetary gear unit 16 includes a sun gear S2, a pinion gear P2, a carrier CA2 that supports the pinion gear P2 so as to rotate and revolve, and a ring gear R2 that meshes with the sun gear S2 via the pinion gear P2. The third planetary gear unit 18 includes a sun gear S3, a plurality of pairs of pinion gears P2 and P3 that mesh with each other, a carrier CA3 that supports the pinion gears P2 and P3 so as to rotate and revolve, and a sun gear S3 via the pinion gears P2 and P3. A meshing ring gear R3 is provided.

  In the second planetary gear device 16 and the third planetary gear device 18, four rotating elements RM <b> 1 to RM <b> 4 are configured by being partially connected to each other. Specifically, the first rotating element RM1 is configured by the sun gear S2 of the second planetary gear unit 16, and the carrier CA2 of the second planetary gear unit 16 and the carrier CA3 of the third planetary gear unit 16 are integrally connected to each other. The second rotating element RM2 is configured, and the ring gear R2 of the second planetary gear unit 16 and the ring gear R3 of the third planetary gear unit 18 are integrally connected to each other to configure the third rotating element RM3, and the third planetary gear unit. The 18th sun gear S3 constitutes a fourth rotating element RM4. In the second planetary gear device 16 and the third planetary gear device 18, the carriers CA2 and CA3 are constituted by a common member, the ring gears R2 and R3 are constituted by a common member, and the second planetary gear device 18 The pinion gear P <b> 2 of the planetary gear device 16 is a Ravigneaux type planetary gear train that also serves as the second pinion gear of the third planetary gear device 18.

  The automatic transmission 10 includes a clutch C1, a clutch C2, a clutch C3, a clutch C4 (hereinafter simply referred to as a clutch C unless otherwise distinguished) as engagement elements for establishing a plurality of gear stages having different gear ratios. A brake B1 and a brake B2 (hereinafter simply referred to as a brake B unless otherwise distinguished) are provided, and the first rotating element RM1 (sun gear S2) is selectively connected to the case 26 via the first brake B1. Thus, the rotation is stopped, the ring gear R1 (that is, the second intermediate output path PA2) of the first planetary gear device 12 that is an intermediate output member is selectively coupled via the third clutch C3, and further, the fourth clutch C4 is further coupled. Are selectively coupled to the carrier CA1 of the first planetary gear unit 12 (that is, the indirect path PA1b of the first intermediate output path PA1). The second rotation element RM2 (carriers CA2 and CA3) is selectively coupled to the case 26 via the second brake B2 and stopped rotating, and the input shaft 22 (ie, the first intermediate) via the second clutch C2. It is selectively connected to the direct connection path PA1a) of the output path PA1. The third rotation element RM3 (ring gears R2 and R3) is integrally connected to the output shaft 24 to output rotation. The fourth rotation element RM4 (sun gear S3) is selectively coupled to the ring gear R1 via the first clutch C1. Between the second rotating element RM2 and the case 26, a one-way clutch F1 that allows forward rotation of the second rotating element RM2 (the same rotation direction as the input shaft 22) and prevents reverse rotation is provided in the second brake. It is provided in parallel with B2.

  The operation table of FIG. 2 is a table for explaining the operation states of the clutches C1 to C4 and the brakes B1 and B2 when each shift stage (gear stage) is established in the automatic transmission 10, and “◯” indicates engagement. The state, “(◯)” represents the engaged state only during engine braking, and the blank represents the released state. Since the one-way clutch F1 is provided in parallel to the brake B2 that establishes the first shift stage “1st”, it is not always necessary to engage the brake B2 when starting (acceleration). Further, the gear ratio of each gear stage is appropriately determined by the gear ratios ρ1, ρ2, and ρ3 of the first planetary gear device 12, the second planetary gear device 16, and the third planetary gear device 18.

  FIG. 3 is a collinear diagram in which the rotational speeds of the rotating elements of the first transmission unit 14 and the second transmission unit 20 can be represented by straight lines, and the lower horizontal line indicates the rotational speed “0”. The horizontal line indicates the rotational speed “1.0”, that is, the same rotational speed as the input shaft 22. Further, each vertical line of the first transmission unit 14 represents the sun gear S1, the ring gear R1, and the carrier CA1 in order from the left side, and the interval therebetween is the gear ratio ρ1 (= sun gear S1 of the first planetary gear unit 12). The number of teeth / the number of teeth of the ring gear R1). The four vertical lines of the second transmission unit 20 indicate the first rotation element RM1 (sun gear S2), the second rotation element RM2 (carrier CA2 and carrier CA3), and the third rotation element RM3 (in order from the left side to the right end. The ring gear R2 and the ring gear R3), the fourth rotating element RM4 (sun gear S3), and the distance between them depends on the gear ratio ρ2 of the second planetary gear device 16 and the gear ratio ρ3 of the third planetary gear device 18. Determined.

  2 and 3, the first clutch C1 and the second brake B2 are engaged, and the fourth rotation element RM4 rotates at a reduced speed with respect to the input shaft 22 via the first transmission unit 14. When the rotation of the second rotation element RM2 is stopped, the third rotation element RM3 connected to the output shaft 24 is rotated at the rotation speed indicated by “1st”, and the largest gear ratio (= input shaft 22). ) / (Rotational speed of output shaft 24)) is established.

  Further, the first clutch C1 and the first brake B1 are engaged, and the fourth rotation element RM4 is decelerated and rotated with respect to the input shaft 22 via the first transmission unit 14, and the first rotation element RM1 is When the rotation is stopped, the third rotation element RM3 is rotated at the rotation speed indicated by “2nd”, and the second speed “2nd” having a speed ratio smaller than that of the first speed “1st” is established.

  Further, the first clutch C1 and the third clutch C3 are engaged, and the fourth rotation element RM4 and the first rotation element RM1 are decelerated and rotated with respect to the input shaft 22 via the first transmission unit 14, and the first rotation element RM1 is rotated. When the second transmission unit 20 is integrally rotated, the third rotation element RM3 is rotated at the rotation speed indicated by “3rd”, and the third shift stage “3rd” having a smaller gear ratio than the second shift stage “2nd” is generated. It is established.

  Further, the first clutch C1 and the fourth clutch C4 are engaged, the fourth rotating element RM4 is decelerated and rotated with respect to the input shaft 22 via the first transmission unit 14, and the first rotating element RM1 is When the input shaft 22 is rotated integrally with the input shaft 22, the third rotation element RM3 is rotated at the rotation speed indicated by "4th", and the fourth shift stage "4th" having a smaller gear ratio than the third shift stage "3rd" is established. Be made.

  Further, the first clutch C1 and the second clutch C2 are engaged, and the fourth rotating element RM4 is decelerated and rotated with respect to the input shaft 22 via the first transmission unit 14, and the second rotating element RM2 is input. When the shaft 22 is rotated together with the shaft 22, the third rotation element RM3 is rotated at a rotational speed indicated by "5th", and the fifth shift stage "5th" having a lower speed ratio than the fourth shift stage "4th" is established. It is done.

  Further, when the second clutch C2 and the fourth clutch C4 are engaged and the second transmission unit 20 is rotated integrally with the input shaft 22, the third rotational element RM3 has a rotational speed indicated by “6th”, that is, the input shaft. Thus, the sixth shift stage “6th” having a smaller gear ratio than the fifth shift stage “5th” is established. The gear ratio of the sixth gear stage “6th” is 1.

  Further, the second clutch C2 and the third clutch C3 are engaged, the first rotating element RM1 is decelerated and rotated with respect to the input shaft 22 via the first transmission unit 14, and the second rotating element RM2 is When rotated integrally with the input shaft 22, the third rotation element RM3 is rotated at the rotational speed indicated by "7th", and the seventh shift stage "7th" having a smaller gear ratio than the sixth shift stage "6th" is established. Be made.

  Further, when the second clutch C2 and the first brake B1 are engaged, the second rotating element RM2 is rotated integrally with the input shaft 22, and when the first rotating element RM1 is stopped from rotating, the third rotating element RM3 is rotated at the rotational speed indicated by “8th”, and the eighth shift stage “8th” having a smaller gear ratio than the seventh shift stage “7th” is established.

  Further, when the third clutch C3 and the second brake B2 are engaged, the first rotating element RM1 is decelerated and rotated through the first transmission unit 14, and the second rotating element RM2 is stopped from rotating. The third rotation element RM3 is reversely rotated at the rotation speed indicated by “Rev1”, and the first reverse shift stage “Rev1” having the largest speed ratio in the reverse rotation direction is established. When the fourth clutch C4 and the second brake B2 are engaged, the first rotating element RM1 is rotated integrally with the input shaft 22, and the second rotating element RM2 is stopped from rotating, and the third rotating element RM3. Is reversely rotated at the rotational speed indicated by “Rev2”, and the second reverse shift stage “Rev2” having a smaller gear ratio than the first reverse shift stage “Rev1” is established. The first reverse speed “Rev1” and the second reverse speed “Rev2” correspond to the first speed and the second speed in the reverse rotation direction, respectively.

  As described above, the automatic transmission 10 of this embodiment establishes a plurality of gear stages having different gear ratios by selectively engaging a plurality of engagement elements, that is, the clutches C1 to C4 and the brakes B1 and B2. There are four clutches C1 to C4 and two brakes by a first transmission unit 14 having two intermediate output paths PA1 and PA2 having different transmission ratios and a second transmission unit 20 having two sets of planetary gear units 16 and 18. Since the forward shift speed of eight gears is achieved by switching the engagement of B1 and B2, it is configured in a small size and the mounting property to the vehicle is improved. Further, as is apparent from the operation table of FIG. 2, it is possible to perform shifts at each gear stage by a so-called clutch-to-clutch that holds either one of the clutches C1 to C4 and the brakes B1 and B2. The clutches C1 to C4 and the brakes B1 and B2 (hereinafter simply referred to as the clutch C and the brake B unless otherwise distinguished) are hydraulic frictions controlled by a hydraulic actuator such as a multi-plate clutch or brake. It is an engagement device.

  FIG. 4 is a block diagram for explaining a main part of a control system provided in the vehicle for controlling the automatic transmission 10 and the like of FIG. The electronic control unit 90 shown in FIG. 4 includes a so-called microcomputer having a CPU, a RAM, a ROM, an input / output interface, and the like, and is stored in advance in the ROM using the temporary storage function of the RAM. By performing signal processing according to a program, output control of the engine 30, shift control of the automatic transmission 10, and the like are executed, and are configured separately for engine control, shift control, etc. as necessary. The

In FIG. 4, the operation amount Acc of the accelerator pedal 50 is detected by the accelerator operation amount sensor 52, and a signal representing the accelerator operation amount Acc is supplied to the electronic control unit 90. The accelerator pedal 50 is largely depressed according to the driver's required output amount, and thus corresponds to an accelerator operation member, and the accelerator operation amount Acc corresponds to an output request amount. In addition, a signal indicating the depression amount θ _SC of the operation of the brake pedal 54 of the foot brake which is a service brake is supplied to the electronic control unit 90. The brake pedal 54 corresponds to the brake operating member from being intended to be largely depressed in response to the deceleration demand of the driver, the amount of depression theta _SC corresponds to the brake operation amount.

Further, an intake air amount sensor 60 for detecting an intake air quantity Q of the engine rotational speed sensor 58, the engine 30 for detecting the rotational speed N _E of the engine 30, the intake for detecting the temperature T _A of intake air The air temperature sensor 62, the throttle valve opening sensor 64 with an idle switch for detecting the fully closed state (idle state) of the electronic throttle valve of the engine 30 and the opening _θTH , the vehicle speed V (the rotational speed N of the output shaft 24). a brake sensor for the cooling water temperature sensor 68 for detecting a vehicle speed sensor 66, cooling water temperature T _W of the engine 30 for detecting the corresponding) to the _OUT, or whether the operation of the brake pedal 54 for detecting a depression amount theta _SC 70, the lever position sensor 74 for detecting a lever position (operating _{position) P SH} of the shift lever 72, turbine Rolling speed _N T AT oil for detecting the turbine rotational speed sensor 76 for detecting a temperature of the hydraulic oil in the hydraulic control circuit 98 AT oil temperature _{T OIL} (= the rotational speed _{N IN} of the input shaft 22) A temperature sensor 78, an acceleration sensor 80 for detecting the acceleration (deceleration) G of the vehicle, and the like are provided. From these sensors and switches, the engine rotational speed N _E , the intake air amount Q, the intake air temperature T are provided. _A , throttle valve opening θ _TH , vehicle speed V, engine cooling water temperature T _W , presence / absence of brake operation or stepping amount θ _SC , lever position P _SH of shift lever 72, turbine rotation speed N _T , AT oil temperature T _OIL , A signal representing the acceleration (deceleration) G of the vehicle is supplied to the electronic control unit 90.

The shift lever 72 is disposed near the driver's seat, for example, and is manually operated to five lever positions “P”, “R”, “N”, “D”, or “S” as shown in FIG. It has become so. The “P” position is a parking position for releasing the power transmission path in the automatic transmission 10 and mechanically preventing (locking) the rotation of the output shaft 24 by the mechanical parking mechanism. The “R” position is an automatic transmission. The reverse travel position for reversing the rotation direction of the output shaft 24 of the machine 10, and the “N” position is a power transmission cutoff position for releasing the power transmission path in the automatic transmission 10. ”Position is a forward travel position in which automatic shift control is executed in a shift range (D range) that allows the first to eighth shifts of the automatic transmission 10, and the“ S ”position is a high speed side that can be shifted. This is a forward travel position where manual shift can be performed by switching between a plurality of shift ranges with different shift stages or a plurality of different shift stages. In this “S” position, the shift range or shift stage is shifted to the up side every time the shift lever 72 is operated, and the shift range or shift stage is shifted to the down side every time the shift lever 72 is operated. A “−” position is provided for The lever position sensor 74 detects whether the shift lever 72 is located at any lever position (operating position) P _SH.

The hydraulic control circuit 98 includes a manual valve connected to the shift lever 72 via a cable, a link, or the like, for example, and the manual valve is mechanically operated as the shift lever 72 is operated. As a result, the hydraulic circuit in the hydraulic control circuit 98 is switched. For example, "D" position and the "S" forward circuit is output forward pressure P _D at position is mechanically established, the first gear position is the forward gear position "1st" to eighth speed "8th It is possible to travel forward while shifting. When the shift lever 72 is operated to the “D” position, the electronic control unit 90 determines that from the signal of the lever position sensor 74 and establishes the automatic shift mode, and sets the first shift stage “1st” to the first shift stage. Shift control is performed using all the forward shift speeds of 8 shift speeds “8th”.

The electronic control unit 90 shifts based on the actual vehicle speed V and the accelerator operation amount Acc from the relationship (map, shift diagram) stored in advance using the vehicle speed V and the accelerator operation amount Acc as parameters as shown in FIG. 6, for example. A shift control means 100 (see FIG. 8) that performs determination and performs shift control so as to obtain the determined shift speed is functionally provided. For example, the vehicle speed V decreases or the accelerator operation amount Acc increases. As a result, a low-speed gear stage having a large gear ratio is established. In this shift control, excitation, de-excitation, and current control of the linear solenoid valves SL1 to SL6 in the shift hydraulic control circuit 98 are executed so that the determined shift stage is established, and the clutch C and brake are controlled. The engagement / release state of B is switched and the transient hydraulic pressure in the shifting process is controlled. That is, by controlling the excitation and non-excitation of the linear solenoid valves SL1 to SL6, the clutch C and the brake B are engaged and disengaged, so that the first shift stage “1st” to the eighth shift stage “8th” are switched. One of the forward shift speeds is established. It should be _noted that various modes are possible, such as performing shift control based on the throttle valve opening θ _TH , the intake air amount Q, the road surface gradient, and the like.

In the shift diagram of FIG. 6, the solid line is a shift line for determining an upshift (upshift line), and the broken line is a shift line for determining a downshift (downshift line). Further, the shift line in the shift diagram of FIG. 6 indicates whether or not the actual vehicle speed V crosses the line on the horizontal line indicating the actual accelerator operation amount Acc (%), that is, the value on which the shift on the shift line is to be executed ( It is for determining whether exceeds the shift point vehicle speed) V _S, also will have been previously stored as a series of the values V _S that shift point vehicle speed. 6 illustrates the shift lines in the first to sixth shift stages among the first to eighth shift stages in which the automatic transmission 10 performs a shift.

  FIG. 7 is a circuit diagram showing a portion related to the linear solenoid valves SL1 to SL6 in the hydraulic control circuit 98, and the hydraulic actuators (hydraulic cylinders) 34, 36, 38, 40 of the clutches C1 to C4 and the brakes B1 and B2. The line hydraulic pressure PL output from the hydraulic pressure supply device 46 is regulated and supplied to the linear pressure valves SL1 to SL6, respectively. The hydraulic pressure supply device 46 includes a mechanical oil pump 48 (see FIG. 1) that is rotationally driven by the engine 30, a regulator valve that regulates the line hydraulic pressure PL, and the like. Is to control. The linear solenoid valves SL1 to SL6 have basically the same configuration, and are excited and de-energized independently by the electronic control unit 90 (see FIG. 4), and the hydraulic pressures of the hydraulic actuators 34 to 44 are independently regulated. It has come to be. In the shift control of the automatic transmission 10, for example, a so-called clutch-to-clutch shift is performed in which the release and engagement of the clutch C and the brake B involved in the shift are controlled simultaneously. For example, as shown in the engagement operation table of FIG. 2, in the downshift from the fifth speed to the fourth speed, the clutch C2 is disengaged and the clutch C4 is engaged, so that the release transient hydraulic pressure of the clutch C2 is suppressed so as to suppress the shift shock. And the engagement transient hydraulic pressure of the clutch C4 are appropriately controlled.

FIG. 8 is a functional block diagram illustrating a main part of the control function of the electronic control unit 90, that is, a control operation at the time of downshifting during coasting (hereinafter referred to as a coast downshift control operation). The shift control means 100 shown in FIG. 8 executes shift determination based on the actual vehicle speed V and the accelerator operation amount Acc from a shift map stored in advance as shown in FIG. 6, for example, and executes the determined shift. A gear output of the automatic transmission 10 is automatically switched by performing a shift output for causing the hydraulic control circuit 98 to perform the shift. For example, when coasting when the automatic transmission 10 is at the third speed, the shift control means 100 performs a third speed → second speed downshift when the actual vehicle speed V is zero and the accelerator operation amount Acc is zero. its engagement when it is determined that exceeds the shift point vehicle speed V _3-2 to be executed, the clutch C3 causes release started, to initiate the engagement of the brake B1 when the engagement torque is maintained to some extent to generate torque, while shifts from the speed ratio gamma ₃ of the third gear position in this state to the gear ratio gamma ₂ of the second gear position, the hydraulic pressure control command to complete the engagement release the brake B1 of the clutch C3 Output to circuit 98.

The deceleration intention determination means 102 determines whether or not there is a driver's intention to decelerate during the shift control by the shift control means 100. This determination is repeatedly executed at a predetermined time period during the coast downshift, and when it is determined that the brake operation is performed, it is determined that the driver intends to decelerate. Preferably, it is determined whether (a) the brake operation is released, (b) the accelerator operation is performed, or (c) the release speed of the brake operation amount is equal to or higher than a predetermined value. It is determined that the driver no longer intends to decelerate. The determination of (a) is made based on on / off of the brake contact signal of the foot brake detected via the brake sensor 70, the brake master cylinder pressure (not shown), etc., and the brake contact signal is turned off. Alternatively, when the brake master cylinder pressure becomes a predetermined value or less, it is determined that the brake operation is released. The determination of (b) is made based on the operation amount Acc of the accelerator pedal 54 detected via the accelerator operation amount sensor 52, and when the accelerator operation amount Acc is not zero, that is, the engine 30 is in an idle state. If not, it is determined that the accelerator operation has been performed. The determination is based on the change rate of the depression amount theta _SC of the foot brake, which is detected via the brake sensor 70 (per predetermined time variation) and not shown brake master cylinder pressure change rate, etc. (c) performed Te, release speed of the brake operation amount is greater than or equal to a predetermined value when the rate of change of case or the brake master cylinder pressure change rate of the brake depression amount theta _SC is reduced below a predetermined value is equal to or less than a predetermined value It is determined. Note that only one of the above determinations (a), (b), and (c) may be performed, and it may be determined that the driver has no intention to decelerate based on the determination.

  In this embodiment, the shift control means 100 includes a shift standby means 104 and a shift progression means 106. The shift standby means 104 increases the engagement pressure of the engagement side engagement element when the determination of the deceleration intention determination means 102 is affirmed, that is, when it is determined that the driver intends to decelerate. Stop to prevent shifting. Here, the engagement side engagement element is a hydraulic friction engagement device on the side to be engaged (newly engaged) with respect to the clutch-to-clutch shift in each coast downshift. In the automatic transmission 10, the clutch C3 is used for the 8th speed → 7th speed downshift, the clutch C4 is used for the 7th speed → 6th speed downshift, the clutch C1 is used for the 6th speed → 5th speed downshift, and the clutch C1 is used for the 5th speed → 4th speed downshift. When C4 is the 4th speed → 3rd speed downshift, the clutch C3 corresponds to the brake B1 when the 3rd speed → 2nd speed downshift, and the brake B2 corresponds to the 2nd speed → 1st speed downshift. That is, in this embodiment, the shift standby unit 104 is supplied to the engagement-side hydraulic friction engagement device via the hydraulic control circuit 98 when the determination of the deceleration intention determination unit 102 is affirmed. The increase of the engagement side hydraulic pressure is stopped to prevent the shift from proceeding. Note that in the 2nd gear → 1st gear downshift, the one-way clutch F1 attached to the brake B2 operates, so that the engagement pressure is not controlled.

  Further, when the increase in the engagement pressure is stopped by the shift standby unit 104, the shift progression unit 106 determines that the determination of the deceleration intention determination unit 102 is negative, that is, the driver does not intend to decelerate. If it is determined, the engagement pressure of the engagement side engagement element is increased again to advance the shift. That is, in this embodiment, when the determination by the deceleration intention determination means 102 is negative, the engagement-side hydraulic pressure supplied to the engagement-side hydraulic friction engagement device via the hydraulic control circuit 98 is determined. The well-known coast down shift is executed in which the gear is raised again to advance the shift.

  8 determines whether the vehicle is turning (during turning). Preferably, the vehicle is in a turning state based on whether or not a steering wheel or a steering angle of a wheel, lateral acceleration (lateral G), corner R, etc. detected by a sensor (not shown) exceeds a predetermined judgment reference value. Determine whether there is. Preferably, the vehicle turning is determined when the accelerator return speed excluding the tip-in operation is greater than or equal to a predetermined value during acceleration orientation, or when the deceleration during braking is greater than or equal to a predetermined value. As a result, it is determined whether the vehicle is traveling before cornering or traveling during cornering without providing a detection device such as a rudder angle sensor. The turning determination means 108 may simply determine whether or not the vehicle is in a turning state, but determines whether or not the turning amount of the vehicle is within a predetermined range. Various aspects are possible.

  Here, the shift standby unit 104 is preferably configured so that the determination by the turning determination unit 108 is negative, that is, the hydraulic friction engagement device on the engagement side on the condition that the vehicle is not in a turning state. The above-described control is performed so as to prevent the shift from proceeding by stopping the increase of the engagement-side hydraulic pressure supplied to. In other words, the shift progression means 106 is preferably connected to the engagement-side hydraulic friction engagement device when the determination of the turning determination means 108 is affirmative, that is, when the vehicle is turning. The shift is advanced by increasing the supplied engagement-side hydraulic pressure.

FIG. 9 is a time chart for explaining an oil pressure command value corresponding to the engagement-side hydraulic friction engagement device, that is, the brake B1, in the third-speed → second-speed downshift as an example of the coast downshift control operation of this embodiment . There is shown an example in which the deceleration intention of the driver is eliminated reacceleration during the shift. The hydraulic pressure command value shown in FIG. 9 is a command value for controlling the engagement state of the brake B1 via the linear solenoid valve SL5 provided in the hydraulic pressure control circuit 98, and the engagement pressure of the brake B1. One-to-one.

In the time chart shown in FIG. 9 , first, at time t1, the shift control means 100 determines the start of the 3rd speed → 2nd speed downshift (shift output), and the supply of hydraulic oil to the brake B1 is started. In other words, so-called first fill control is executed, and the flow rate of the hydraulic oil output from the output port of the linear solenoid valve SL5 is rapidly increased. Next, when the operation of the foot brake is detected by the brake sensor 70 at time t2, and the determination of the deceleration intention determination means 102 is affirmed, that is, when it is determined that the driver intends to decelerate, the linear solenoid After the engagement-side hydraulic pressure supplied to the brake B1 is raised to a predetermined pressure via the valve SL5, the rise is stopped and maintained, and control is performed so that the shift is not further advanced. Next, when the release of the foot brake is detected by the brake sensor 70 at time t3 ′ and the determination of the intention to decelerate determination unit 102 is negative, that is, when it is determined that the driver does not intend to decelerate, the linear The increase of the engagement side hydraulic pressure supplied to the brake B1 via the solenoid valve SL5 is started again. At time t4, the brake B1 is completely engaged, and the third-speed → second-speed downshift is completed. Incidentally, such a control, not only when the brake operation by the driver after the shift output has been started is performed, the line from the time t1 before the brake operation by the driver is determined third speed → 2 gear downshift Even if it is a case, it is executed in the same way.

As shown in FIG. 9 described above, in the control of this embodiment, the brake B1 is engaged in a state where the determination of the deceleration intention determination unit 102 is affirmative, that is, a state where it is determined that there is a driver's intention to decelerate. While the pressure increase is stopped to prevent the shift from proceeding, the determination of the deceleration intention determination means 102 is denied in the state where the increase in the engagement pressure of the brake B1 is stopped in that way, that is, When it is determined that the driver does not intend to decelerate, the engagement pressure of the brake B1 is increased again to advance the shift. In downshifting during coasting (coast), coasting down shift control is generally performed in preparation for the depression of the accelerator so that acceleration can be accelerated with an appropriate driving force when accelerating again. If the determination is affirmative, that is, if it is determined that the driver intends to decelerate, the transition from the deceleration state to the vehicle stop state can be considered. By doing so, it is possible to suitably suppress the occurrence of a shift shock. On the other hand, if the determination by the deceleration intention determination means 102 is negative, that is, a state where it is determined that the driver does not intend to decelerate, it is possible that the vehicle is decelerated from the time of deceleration. In order to accelerate the coast down shift and accelerate with an appropriate driving force in response, prepare for the accelerator depression. Here, in the control of the present embodiment, since the shift proceeds by releasing the brake operation, there is a possibility that the down shift is performed after the release, but the brake-off shock and the shift shock that are felt by the driver. Therefore, there is also an advantage that it is possible to suppress the driver from feeling it as a shift shock by overlapping the shift shock with the shock caused by the intentional brake-off operation.

FIG. 10 is a time chart showing the torque of the output shaft 24 and the on / off of the brake in the turning state of the vehicle corresponding to the time chart of FIG. 9 , and the output shaft torque by the control of this embodiment is indicated by a solid line. The output shaft torque by conventional control that does not stop the increase in the engagement pressure of the brake B1 is indicated by dotted lines. When the vehicle is turning, there is a high possibility that the accelerator pedal 50 is depressed and accelerated again immediately after the brake operation is released. However, when the control of this embodiment described above is performed, that is, the brake In an aspect in which the coast down shift control is prevented from proceeding by the operation, and the coast down shift control is re-advanced at the same time as the release of the brake operation, the accelerator pedal 50 is stepped on immediately after the release of the brake operation, so Once, there can be a somewhat characteristic shift shock occurs within a short period of time as indicated by a solid line in the time t3 'onward in FIG 10. Therefore, in this embodiment, as described above, when the determination of the turning determination means 108 is affirmative, that is, when the vehicle is in a turning state, the engagement side hydraulic pressure supplied to the brake B1 is increased to change the speed. Make it progress. Thus, coasting downshift conventional control similarly to the third speed → 2-speed is caused to rapidly completed, it is possible to suppress such a shift shock as shown by the dotted line in FIG. 10.

FIG. 11 is a flowchart for explaining a main part of the coast down shift control by the electronic control unit 90, which is repeatedly executed at a predetermined cycle.

First, in step (hereinafter, step is omitted) S1, it is determined whether or not a coast downshift is being performed, that is, whether or not it is a downshift during coasting (coast). If the determination in S1 is negative, the routine is terminated accordingly. If the determination in S1 is affirmative, in S2 corresponding to the operation of the deceleration intention determination means 102, the driver's It is determined whether or not there is an intention to decelerate. For example, when the brake contact signal is turned on based on ON / OFF of the brake contact signal of the foot brake detected via the brake sensor 70, the brake master cylinder pressure not shown, or the like, or the brake master cylinder pressure Is greater than or equal to a predetermined value, it is determined that the driver intends to decelerate. Further, when the brake contact signal is turned off, or when the brake master cylinder pressure becomes a predetermined value or less, or based on the operation amount Acc of the accelerator pedal 54 detected through the accelerator operation amount sensor 52, etc. When the accelerator operation amount Acc is not zero, that is, when the engine 30 is not in the idle state, it is determined that there is no intention to decelerate. Further, based on the change rate (change amount per predetermined time) of the foot brake depression amount θ _SC detected via the brake sensor 70, the change rate of the brake master cylinder pressure (not shown), etc., the brake depression amount θ _{When the SC} change rate is less than or equal to a predetermined value or when the brake master cylinder pressure change rate is less than or equal to a predetermined value, it is determined that the brake operation release speed is greater than or equal to a predetermined value. It is judged that there is no. If the determination in S2 is negative, that is, if it is determined that the driver does not intend to decelerate, the engagement is made via the hydraulic control circuit 98 in S4 corresponding to the operation of the shift advancement means 106. This routine is terminated after the engagement-side hydraulic pressure supplied to the hydraulic friction engagement device on the side is increased and coast-down shift control is resumed, but when the determination in S2 is affirmative, that is, If it is determined that the driver intends to decelerate, in S3 corresponding to the operation of the turning determination means 108, it is determined whether or not the vehicle is in a turning state (turning). For example, based on whether or not the steering wheel or wheel steering angle, lateral acceleration (lateral G), corner R, etc. detected by a sensor (not shown) exceeds a predetermined criterion value, the criterion is exceeded. In this case, it is determined that the vehicle is turning. Further, if the accelerator return speed excluding the tip-in operation is greater than or equal to a predetermined value during acceleration orientation, or if the deceleration during braking is greater than or equal to a predetermined value, it is determined that the vehicle is turning. If the determination in S3 is affirmative, the processes in and after S4 are executed. If the determination in S3 is negative, in S5 corresponding to the operation of the shift standby means 104, the hydraulic control circuit After the engagement-side hydraulic pressure supplied to the engagement-side hydraulic friction engagement device via 98 is stopped and the shift is not allowed to proceed, this routine is terminated.

  As described above, according to this embodiment, the intention of the deceleration intention determination unit 102 (S2) for determining whether or not the driver intends to decelerate during the coast downshift and the determination of the deceleration intention determination unit 102 are positive. In this case, the shift standby means 104 (S5) stops the increase in the engagement pressure of the engagement side engagement element so that the shift does not proceed, and the shift standby means 104 increases the engagement pressure. If the determination of the intention to decelerate determination unit 102 is negative in the stopped state, the shift advancement unit 106 (S4) that increases the engagement pressure of the engagement side engagement element again to advance the shift. Therefore, if the driver intends to decelerate, i.e., it is considered that the driver intends to shift from the deceleration state to the stop state, it is unnecessary to prevent the coast down shift from proceeding. In addition to being able to prevent a shift shock from occurring by coast downshift, if no longer deceleration intention of the driver by advancing the coast downshift, can be accelerated well response when accelerating again during deceleration. That is, it is possible to provide a shift control device for the automatic transmission 10 for a vehicle that can reduce a shift shock while enabling acceleration with good response when the vehicle is accelerated again from the time of deceleration.

  In addition, the engagement element is a hydraulic friction engagement device, and the shift standby unit 104 is configured such that when the determination of the deceleration intention determination unit 102 is affirmative, the hydraulic friction engagement device on the engagement side. The shift side advancement means 106 stops the increase of the engagement side hydraulic pressure supplied to the engine so that the speed change progress means 106 does not advance the speed change when the determination of the deceleration intention determination means 102 is negative. The engagement side hydraulic pressure supplied to the hydraulic friction engagement device on the side is increased again to advance the shift, so that the practical vehicle automatic transmission 10 having a plurality of hydraulic friction engagement devices is provided. In this case, it is possible to reduce the shift shock while enabling the vehicle to accelerate with good response when accelerating again from the time of deceleration of the vehicle.

  In addition, the deceleration intention determination unit 102 determines whether the driver has released the brake operation, the accelerator operation, or the release speed of the brake operation amount is a predetermined value or more. Therefore, the presence or absence of the driver's intention to decelerate can be suitably determined.

  Further, the vehicle has a turning determination unit 108 (S3) for determining whether or not the vehicle is turning, and the shift standby unit 104 is conditioned on the condition that the determination of the turning determination unit 108 is negative. Since the increase in the engagement pressure of the mating engagement element is stopped to prevent the shift from proceeding, when the vehicle is turning, it is again immediately after the brake operation is performed for turning. Since the possibility of acceleration is high, it is possible to suitably suppress the deterioration in acceleration during such re-acceleration.

  Although the preferred embodiments of the present invention have been described in detail with reference to the drawings, the present invention can be implemented with various modifications without departing from the spirit of the present invention.

  For example, in the above-described embodiment, the automatic transmission 10 has a plurality of hydraulic friction engagement devices, that is, as engagement elements for establishing a plurality of gear stages having different gear ratios by selective engagement. Although the clutch C and the brake B were provided, the present invention is not limited to this. For example, the clutch C and the brake B are provided with an engagement element by electromagnetic control such as an electromagnetic clutch or a magnetic powder clutch. Also good. In this case, the shift standby unit 104 and the shift progression unit 106 control the engagement pressures of the engagement elements by controlling command signals supplied to the engagement elements.

  In the above-described embodiment, the release pressure of the release-side hydraulic friction engagement device and the engagement pressure of the engagement-side hydraulic friction engagement device are directly applied using the linear solenoid valves SL1 to SL6. Although direct pressure control for performing downshifting by control has been described, a linear solenoid valve is not provided corresponding to each hydraulic friction engagement device, and other control methods are not direct pressure control. The present invention is also suitably applied to a speed change mechanism that uses this hydraulic control circuit.

In the above-described embodiment, the control including the one-way clutch shift has been described. However, the present invention is widely applied to a coast down shift by switching between the disengagement engagement element and the engagement engagement element when the vehicle is decelerated. Needless to say, the present invention is also suitably applied to clutch-to-clutch shift control not including one-way clutch shift.

  In addition, although not illustrated one by one, the present invention is implemented with various modifications within a range not departing from the gist thereof.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a skeleton diagram illustrating a configuration of a vehicle automatic transmission to which the present invention is preferably applied. FIG. 3 is an operation table for explaining the operation of the engagement elements when a plurality of shift speeds are established in the automatic transmission of FIG. 1. FIG. 3 is a collinear diagram that can represent the rotational speeds of the rotating elements of the first transmission unit and the second transmission unit provided in the automatic transmission of FIG. 1 by straight lines. FIG. 2 is a block diagram illustrating a main part of a control system provided in the vehicle for controlling the automatic transmission of FIG. 1 and the like. It is a figure explaining the operation position of the shift lever of FIG. It is a figure which shows an example of the shift map used in the shift control of the electronic controller of FIG. It is a figure explaining the principal part of the hydraulic control circuit of FIG. FIG. 5 is a functional block diagram illustrating a main part of a control function of the electronic control device of FIG. 4, that is, a control operation at the time of downshift during inertial running. FIG. 5 is a time chart for explaining a hydraulic pressure command value corresponding to a hydraulic friction engagement device on the engagement side in a third speed → second speed downshift as an example of coast down shift control operation by the electronic control unit of FIG. In this example, the driver decelerates and the vehicle is reaccelerated. FIG. 10 is a time chart showing the output shaft torque and on / off of the brake in a turning state of the vehicle corresponding to the time chart of FIG. 9 , and the output shaft torque by the control of the present invention is shown by a solid line, and the hydraulic friction on the engagement side The output shaft torque by the conventional control that does not stop the increase in the engagement pressure of the engagement device is shown by dotted lines. 6 is a flowchart for explaining a main part of coast down shift control by the electronic control unit of FIG. 4.

Explanation of symbols

10: Automatic transmission 102 for vehicle: Deceleration intention determination means 104: Shift waiting means 106: Shift progress means 108: Turn determination means B1, B2: Brake (engagement element, hydraulic friction engagement device)
C1, C2, C3, C4: Clutch (engagement element, hydraulic friction engagement device)

Claims (4)

In an automatic transmission for a vehicle that establishes a plurality of gear stages having different gear ratios by selectively increasing engagement pressures related to a plurality of engagement elements and selectively engaging the plurality of engagement elements . A shift control device for an automatic transmission for a vehicle that performs a coast down shift by re-engaging the disengagement side engagement element and the engagement side engagement element when the vehicle decelerates
Deceleration intention determination means for determining whether or not there is a driver's intention to decelerate during the coast down shift based on the driver's brake operation and accelerator operation ;
A shift standby means for stopping the increase in the engagement pressure of the engagement side engagement element so that the shift does not proceed when the determination of the deceleration intention determination means is affirmative;
In the state where the increase of the engagement pressure is stopped by the shift standby unit, when the determination of the deceleration intention determination unit is negative, the engagement pressure of the engagement side engagement element is increased again to change the speed. A shift control device for an automatic transmission for a vehicle, comprising: The engagement element is a hydraulic friction engagement device;
The shift standby means stops the increase of the engagement side hydraulic pressure supplied to the engagement side hydraulic friction engagement device so that the shift does not proceed when the determination of the deceleration intention determination means is affirmed. Is what
The shift advance means is configured to increase the engagement side hydraulic pressure supplied to the engagement side hydraulic friction engagement device again to advance the shift when the determination of the deceleration intention determination means is negative. The shift control apparatus for a vehicle automatic transmission according to claim 1.   The deceleration intention determination means is configured to determine whether the driver intends to decelerate when the brake operation is released, the accelerator operation is performed, and the release speed of the brake operation amount is greater than or equal to a predetermined value. The shift control device for a vehicle automatic transmission according to claim 1 or 2, wherein it is determined that there is no more.   The vehicle has a turning determination means for determining whether or not the vehicle is in a turning state, and the shift standby means engages the engagement-side engagement element on the condition that the determination of the turning determination means is denied. The shift control device for an automatic transmission for a vehicle according to any one of claims 1 to 3, wherein the increase in pressure is stopped to prevent the shift from proceeding.

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