JP2010164102A - Driving force transmitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To inhibit an overshoot even when each of engaging hydraulic clutches is changed over. <P>SOLUTION: This driving force transmitting device includes a left shift solenoid valve 108L and a right shift solenoid valve 108R changing over and connecting passages connected to a left clutch CL and a right clutch CR respectively to discharge passages L6(L7) and passages L4(L5) supplied with oil pressure regulated by a linear solenoid valve 106. When each of the engaging clutches is changed over, the passage connected to the left clutch CL to be engaged after change over with time delay is connected to the passage L4 after the passage connected to the right clutch CR to be disengaged is connected to the discharge passage L7 if target oil pressure of the right clutch CR to be disengaged is higher than target oil pressure of the left clutch CL to be engaged after change over. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a driving force transmission device capable of selectively engaging a plurality of hydraulic clutches and switching a driving force transmission path.

  For example, Patent Document 1 discloses a vehicle driving force distribution device that distributes and transmits engine driving force to left and right wheels by selectively controlling the engagement states of a plurality of hydraulic clutches. ing.

  In the vehicle driving force distribution device disclosed in Patent Document 1, a hydraulic pump that supplies hydraulic oil to a hydraulic clutch, a linear solenoid valve that adjusts hydraulic oil supplied from the hydraulic pump to a constant hydraulic pressure, and And left and right shift solenoid valves that are connected to the linear solenoid valves and that control the engagement / disengagement of the left and right hydraulic clutches by opening and closing an oil passage communicating with the left and right hydraulic clutches. Yes.

  In this case, in the vehicle driving force distribution device disclosed in Patent Document 1, for example, since the engagement state and the disengagement state of the left and right hydraulic clutches are selectively controlled, for example, the vehicle is moved to the right When switching from the turning state to the left turning state, the disengagement of the right hydraulic clutch and the engagement of the left hydraulic clutch are performed simultaneously.

JP 9-310748 A

  However, if the oil passage of the right shift solenoid valve is closed and the right hydraulic clutch is disengaged, and at the same time the oil passage of the left shift solenoid valve is opened and the left hydraulic clutch is engaged, the upstream of the left and right shift solenoid valves Due to the influence of the hydraulic pressure (residual pressure) remaining in the linear solenoid valve disposed on the side, there is a possibility that an overshoot of the hydraulic pressure may occur in the engaged left hydraulic clutch.

  The present invention has been made in view of the above points, and provides a driving force transmission device capable of suppressing the occurrence of overshoot even when the hydraulic clutches to be engaged are switched. The purpose is to do.

  To achieve the above object, the present invention is a driving force transmission device that selectively engages a plurality of hydraulic clutches and switches a driving force transmission path for transmitting the driving force of a driving source, A hydraulic pump for generating a hydraulic pressure to be supplied to each hydraulic clutch; a pressure regulating valve for regulating a hydraulic pressure discharged from the hydraulic pump to a target hydraulic pressure; and a corresponding one of the plurality of hydraulic clutches, When switching an oil passage connected to the clutch between a hydraulic supply passage to which the hydraulic pressure regulated by the pressure regulating valve is supplied and a hydraulic drainage passage, and a hydraulic clutch to be engaged, When the target hydraulic pressure of the hydraulic clutch to be disengaged is larger than the target hydraulic pressure of the hydraulic clutch to be engaged after switching, an oil path connected to the hydraulic clutch to be disengaged is defined as the hydraulic oil drain path. Close to And a switching control means for controlling the switching of the switching valve so that an oil passage connected to the hydraulic clutch engaged after switching is connected to the hydraulic supply passage with a time delay. To do.

  According to the present invention, when switching each engaged hydraulic clutch, if the target hydraulic pressure of the hydraulic clutch to be disengaged is greater than the target hydraulic pressure of the hydraulic clutch to be engaged after switching, the engagement is released. After connecting the oil passage connected to the hydraulic clutch to be connected to the hydraulic oil discharge passage, the oil passage connected to the hydraulic clutch engaged after the switching is connected to the hydraulic supply passage with a predetermined time delay. In addition, the switching valve is controlled to be switched. Therefore, in the present invention, it is possible to suppress the occurrence of overshoot that temporarily increases the pressure at the start of operation of the engaged hydraulic clutch.

  Furthermore, the present invention is a driving force transmission device that selectively engages a plurality of hydraulic clutches and switches a driving force transmission path for transmitting the driving force of a driving source, and is supplied to each hydraulic clutch. A hydraulic pump that generates hydraulic pressure, a pressure regulating valve that regulates the hydraulic pressure discharged from the hydraulic pump to a target hydraulic pressure, and an oil passage that is provided corresponding to each of the plurality of hydraulic clutches and connected to the hydraulic clutch And a switching valve for switching between a hydraulic pressure supply path to which a hydraulic pressure regulated by the pressure regulating valve is supplied and a hydraulic oil drainage path, and a corresponding one of the plurality of hydraulic clutches. When switching the hydraulic sensor that detects the actual hydraulic pressure value of the clutch and the hydraulic clutch to be engaged, the target hydraulic pressure of the hydraulic clutch that is disengaged is the same as the target hydraulic pressure of the hydraulic clutch that is engaged after the switching. Is greater than the oil pressure drain oil passage, the actual hydraulic pressure value of the hydraulic clutch to be disengaged detected by the oil pressure sensor is connected to the oil pressure drain oil passage. The switching valve is configured to connect an oil passage connected to the hydraulic clutch engaged after the switching to the hydraulic supply passage when the pressure decreases to a vicinity of a target value of the hydraulic clutch engaged after the switching. And a switching control means for switching and controlling.

  According to the present invention, when switching each engaged hydraulic clutch, if the target hydraulic pressure of the hydraulic clutch to be disengaged is greater than the target hydraulic pressure of the hydraulic clutch to be engaged after switching, the engagement is released. After the oil path connected to the hydraulic clutch to be connected is connected to the hydraulic oil discharge path, the actual hydraulic value of the hydraulic clutch to be disengaged decreases to near the target value of the hydraulic clutch to be engaged after switching At that time, the switching valve is controlled to switch so that the oil passage connected to the hydraulic clutch engaged after the switching is connected to the hydraulic pressure supply passage. Therefore, in the present invention, it is possible to suppress the occurrence of overshoot that temporarily increases the pressure at the start of operation of the engaged hydraulic clutch.

  Even when each of the hydraulic clutches to be engaged is switched, it is possible to obtain a driving force transmission device that can suppress the occurrence of overshoot.

1 is an overall configuration diagram of a vehicle to which a driving force transmission device according to an embodiment of the present invention is applied. It is a skeleton figure which shows the structure of the said driving force transmission apparatus. It is a longitudinal cross-sectional view which shows the specific structure of the said driving force transmission apparatus. FIG. 4 is an enlarged vertical sectional view of a part IV in FIG. 3. FIG. 4 is an enlarged vertical sectional view of a V portion in FIG. 3. It is a circuit structure figure of a part of hydraulic circuit which supplies oil with respect to each clutch. It is a circuit structure figure of the remaining part of the hydraulic circuit. It is a longitudinal cross-sectional view which shows an effect | action of the driving force transmission apparatus at the time of the left turn in a medium-low vehicle speed area. It is a longitudinal cross-sectional view which shows an effect | action of the driving force transmission apparatus at the time of the right turn in a medium-low vehicle speed area. It is explanatory drawing which shows the time chart which concerns on this embodiment. It is explanatory drawing which shows the time chart which concerns on other embodiment. It is explanatory drawing which shows the time chart which concerns on a comparative example.

  Next, embodiments of the present invention will be described in detail with reference to the drawings as appropriate. FIG. 1 is an overall configuration diagram of a vehicle to which a driving force transmission device according to an embodiment of the present invention is applied.

  As shown in FIG. 1, the front engine / front drive vehicle includes left and right front wheels WFL and WFR as drive wheels, and left and right rear wheels WRL and WRR as driven wheels. A transmission M is connected to the left end of an engine (drive source) E mounted horizontally at the front of the vehicle body, and a differential mechanism D and a torque distribution mechanism A are connected to the rear of the engine E and transmission M. Arranged. A left front wheel WFL and a right front wheel WFR are connected to a left axle AFL and a right axle AFR that extend left and right from the left end and right end of the differential mechanism D and the torque distribution mechanism A, respectively.

  FIG. 2 is a skeleton diagram showing the structure of the driving force transmission device, and FIG. 3 is a longitudinal sectional view showing the specific structure of the driving force transmission device.

  As shown in FIGS. 2 and 3, the differential mechanism D to which the driving force is transmitted from the external gear 3 meshed with the input gear 2 provided on the input shaft 1 extending from the transmission M is a double pinion type. Consists of a planetary gear mechanism. The planetary gear mechanism includes a ring gear 4 formed integrally with the external gear 3, a sun gear 5 disposed coaxially within the ring gear 4, an outer planetary gear 6 meshing with the ring gear 4, and the sun gear. 5 has a planetary carrier 8 that supports an inner planetary gear 7 that meshes with 5 in a state where they mesh with each other.

  In the differential mechanism D, the ring gear 4 functions as an input element, and the sun gear 5 that functions as one output element is connected to the right front wheel WFR via the right output shaft 9R, the half shaft 10, and the right axle AFR, and The planetary carrier 8 that functions as the other output element is connected to the left front wheel WFL via the left output shaft 9L and the left axle AFL.

  The torque distribution mechanism A that distributes the driving force between the left and right front wheels WFL, WFR is composed of a planetary gear mechanism, and the carrier member 11 is rotatably supported on the outer periphery of the right output shaft 9R and extends in the circumferential direction. A triple pinion member 16 integrally formed with a first pinion 13, a second pinion 14, and a third pinion 15 is rotatably supported on each of four pinion shafts 12 arranged at an angle of 90 degrees. Is done.

  The first sun gear 17 that is rotatably supported on the outer periphery of the half shaft 10 and meshes with the first pinion 13 is connected to the right carrier half 8R of the planetary carrier 8 of the differential mechanism D. The second sun gear 18 fixed to the outer periphery of the half shaft 10 is provided so as to mesh with the second pinion 14. Further, the third sun gear 19 rotatably supported on the outer periphery of the right output shaft 9R is provided so as to mesh with the third pinion 15.

  In the present embodiment, the number of teeth of the first pinion 13, the second pinion 14, the third pinion 15, the first sun gear 17, the second sun gear 18, and the third sun gear 19 is set as follows.

Number of teeth of the first pinion 13 Zb = 16
Number of teeth of second pinion 14 Zd = 16
Number of teeth of the third pinion 15 Zf = 32
Number of teeth of the first sun gear 17 Za = 30
Number of teeth of second sun gear 18 Zc = 26
Number of teeth of the third sun gear 19 Ze = 28

  The third sun gear 19 is provided so as to be connectable to the housing 20 of the torque distribution mechanism A via the right clutch CR, and the rotational speed of the carrier member 11 is increased by the engagement of the right clutch CR. The carrier member 11 is provided so as to be connectable to the housing 20 via the left clutch CL, and the rotation speed of the carrier member 11 is reduced by the engagement of the left clutch CL.

  The electronic control unit ECU calculates the engine torque Te, the engine rotational speed Ne, the vehicle speed V, and the steering angle θ based on a predetermined program, and operates the left clutch CL and the right clutch CR via a hydraulic circuit 100 described later. It functions as a switching control means for switching and controlling alternatively.

  Next, the structures of the differential mechanism D and the torque transmission mechanism A will be described in detail below with reference to FIGS. 4 is an enlarged vertical cross-sectional view of the IV part shown in FIG. 3, and FIG. 5 is an enlarged vertical cross-sectional view of the V part of FIG.

  As shown in FIG. 3, the differential case 33 constitutes an outline of the differential mechanism D that is accommodated between the left transmission case 31 and the right transmission case 32. In the differential case 33, the first case 34 and the second case 35 are integrally connected by a bolt 36, and the external gear 3 is fastened together by the bolt 36.

  The first case 34 is rotatably supported by the left transmission case 31 via a roller bearing 37, and the second case 35 is rotatably supported by the right transmission case 32 via a roller bearing 38. The output of the transmission M is transmitted from the input gear 2 through the external gear 3 to the differential case 33 of the differential mechanism D.

  The planetary carrier 8 is divided into a left carrier half 8L and a right carrier half 8R, and the left output shaft 9L penetrates the first case 34 in a relatively rotatable manner and is splined to the left carrier half 8L. The right output shaft 9R passes through the second case 35 so as to be relatively rotatable, and is splined to the sun gear 5.

  The left and right carrier halves 8L and 8R are integrally connected via an outer pinion pin 39 and an inner pinion pin 40, and the outer planetary gear 6 is rotatably supported by the outer pinion pin 39. On the other hand, the inner planetary gear 7 is rotatably supported.

  As shown in FIGS. 3 and 5, the torque distribution mechanism A has a left case 41 and a right case 42 that are integrally coupled by a bolt 43, and is supported by a ball bearing 44 inside thereof. The left end of the half shaft 10 is splined to the right end of the right output shaft 9R. Provided on the outer periphery of the left portion of the second sun gear 18 formed integrally with the half shaft 10 is a sleeve 46 supported on the left case 41 via a ball bearing 45 so as to be relatively rotatable. The first sun gear 17 is splined to the right end of the sleeve 46.

  As shown in FIGS. 3 and 4, there is provided a sleeve 47 that is rotatably fitted to the outer periphery of the right output shaft 9 </ b> R and whose left end is splined to the right carrier half 8 </ b> R of the differential mechanism D. The right end of the sleeve 47 is splined to the left end of the sleeve 46. As a result, the first sun gear 17 is coupled to the right carrier half 8R via the sleeves 46 and 47.

  As shown in FIG. 5, the left clutch (hydraulic clutch) CL is disposed between the left end of the carrier member 11 and the left case 41. The left clutch CL includes a friction engagement member 50 disposed between a clutch inner 48 provided on the carrier member 11 and a clutch outer 49 provided on the left case 41, and the friction engagement member 50 is hydraulically operated. A clutch piston 51 to be engaged and a return spring 52 that presses the clutch piston 51 in a disengagement direction by a spring force.

  A third sun gear 19 is rotatably supported on the outer periphery of the right half shaft 10 of the second sun gear 18 via a ball bearing 53. The right clutch (hydraulic clutch) CR includes a friction engagement member 56 disposed between a clutch inner 54 formed integrally with the third sun gear 19 and a clutch outer 55 provided in the right case 42, and the friction A clutch piston 57 that engages the engagement member 56 with hydraulic pressure, and a return spring 58 that presses the clutch piston 57 in a disengagement direction by a spring force.

  The carrier member 11 of the torque distribution mechanism A is supported on the outer periphery of the sleeve 46 via a ball bearing 59 and supported on the outer periphery of the clutch inner 54 via a ball bearing 60.

  As shown in FIG. 4, the pump unit 61 that supplies oil (hydraulic oil) to the torque distribution mechanism A includes a pump body 63, a separator plate 64, and a pump cover 65 that are integrally coupled by bolts 62. The pump body 63 is fixed to the left case 41 of the torque distribution mechanism A with a bolt 66 in a state where the pump body 63 is engaged with the right transmission case 32.

  A trochoid oil pump (hydraulic pump) 67 for generating hydraulic pressure supplied to the left and right clutches CL and CR is housed in a pump chamber 63a formed in the pump body 63. The oil pump 67 is configured by meshing the inner teeth of the outer rotor 68 disposed on the radially outer side with the inner rotor 69 disposed on the radially inner side.

  A rotating shaft 71 coupled to the inner rotor 69 via a pin 70 is supported on the pump body 63 and the pump cover 65 by ball bearings 73 and 74. A driven gear 75 is connected to one end portion of the rotating shaft 71 protruding leftward from the pump body 63 via the seal member 72, and the driven gear 75 is a drive provided on the outer periphery of the first case 35 of the differential case 33. It is provided so as to mesh with the gear 76.

  The separator plate 64 and the pump cover 65 are respectively provided with a suction port 78 and a discharge port 79 communicating with a working chamber 77 formed between the outer rotor 68 and the inner rotor 69.

Next, the hydraulic circuit 100 will be described in detail below based on FIG. 6 and FIG.
FIG. 6 is a circuit structure diagram of a part of the hydraulic circuit, and FIG. 7 is a circuit structure diagram of the remaining part of the hydraulic circuit.

  The hydraulic circuit 100 includes an oil passage L2 (see FIG. 6 and FIG. 6) connected to a regulator valve 102 that primarily regulates the oil pumped up from the oil reservoir 101 through the oil passage L1 by the oil pump 67. And a linear solenoid valve (pressure regulating valve) 106 that secondarily regulates the oil that has been introduced through the regulator valve 102 and is primarily regulated by the regulator valve 102 to a predetermined target hydraulic pressure. .

  As shown in FIG. 7, the oil passage L3 connected to the output side of the linear solenoid valve 106 is bifurcated in the middle, and the branched one oil passage L3a is a left shift solenoid valve (switching valve). The other branched oil passage L3b is connected to the input side of the right shift solenoid valve (switching valve) 108R.

  The output side of the left shift solenoid valve 108L is connected to the left clutch CL via an oil passage (hydraulic supply passage) L4 in which a left hydraulic sensor 110L is interposed, while the output side of the right shift solenoid valve 108R is The right hydraulic pressure sensor 110R is connected to the right clutch CR via an oil passage (hydraulic supply passage) L5. On the output side of the left shift solenoid valve 108L and the output side of the right shift solenoid valve 108R, there are an oil discharge passage (hydraulic oil discharge passage) L6 and an oil discharge passage (hydraulic oil discharge passage) L7 communicating with the oil reservoir 101. Each is connected.

  In FIG. 6, reference numeral 112 denotes a cooler relief valve, reference numeral 114 denotes a lubrication / cooler relief valve, reference numeral 116 denotes a drain filter, and reference numeral 118 denotes a radiator built-in chilled water cooler.

  In this case, the linear solenoid valve 106, the left shift solenoid valve 108L, and the right shift solenoid valve 108R are electrically connected to the electronic control unit ECU, respectively, and control signals (linear solenoids described later) output from the electronic control unit ECU. And a signal for controlling switching of the left shift solenoid valve 108L and a signal for controlling switching of the right shift solenoid valve 108R).

  Further, a temperature detection signal detected by the oil temperature sensor 104 and corresponding to the temperature of the oil flowing through the oil passage L2, an actual oil pressure (left clutch CL) detected by the left hydraulic sensor 110L and operating the clutch piston 51 of the left clutch CL. The pressure detection signal consisting of the actual pressure) and the pressure detection signal consisting of the actual oil pressure (right clutch CR actual pressure) detected by the right hydraulic pressure sensor 110R and operating the clutch piston 57 of the right clutch CR are respectively electronically controlled. Input to the unit ECU.

  Based on the command pressure signal from the electronic control unit ECU, the linear solenoid valve 106 further regulates the oil pressure of the oil primarily regulated in the regulator valve 102 to arbitrarily apply the engagement force of the left clutch CL and the right clutch CR. To be adjusted.

  The left shift solenoid valve 108L is controlled to be turned on / off by the electronic control unit ECU to open / close the oil passage L4, thereby switching the engagement / disengagement of the left clutch CL. The right shift solenoid valve 108R is on / off controlled by the electronic control unit ECU to open / close the oil passage L5, thereby switching the engagement / disengagement of the right clutch CR.

  In other words, the output side of the left shift solenoid valve 108L is connected to the oil drain path L6 in an off state in which no current flows through the solenoid unit, while the solenoid unit is energized and turned on, not shown. When the movable core is sucked toward the fixed core and the movable core and the spool are integrally displaced, it is possible to switch to a state where the oil passage L6 is connected to the oil passage L4 communicating with the left clutch CL. When the output side of the left shift solenoid valve 108L is connected to the oil passage L4, oil is supplied to the left clutch CL via the oil passage L4 to operate the clutch piston 51 and engage the left clutch CL. Can do.

  The right shift solenoid valve 108R is the same as the left shift solenoid valve 108L, and the output side of the right shift solenoid valve 108R is connected to the oil drain path L7 in an off state in which no current flows through the solenoid portion. On the other hand, when the solenoid is energized and turned on, the movable core (not shown) is attracted to the fixed core side, and the movable core and the spool are integrally displaced. It can be switched to a state connected to the oil passage L5 communicating with the. When the output side of the right shift solenoid valve 108R is connected to the oil passage L5, oil is supplied to the right clutch CR via the oil passage L5 to operate the clutch piston 57 and to engage the right clutch CR. Can do.

  The oil discharged through the oil discharge passages L6 and L7 connected to the output side of the left shift solenoid valve 108L and the right shift solenoid valve 108R is stored in the oil reservoir 101. Further, the lubricating oil passage L8 extending from the regulator valve 102 communicates with the outer periphery of the half shaft 10 through the housing 20 as indicated by a circle C in FIGS. 6 and 7.

  Further, in the present embodiment, the left and right clutches CL and CR provided with the differential mechanism D and the torque transmission mechanism A are illustrated, but the present invention is not limited to this, for example, hydraulic control of an automatic transmission (not shown) It can also be applied to a circuit or the like.

  The vehicle to which the driving force transmission device according to the present embodiment is applied is basically configured as described above. Next, the function and effect will be described. FIG. 8 is a longitudinal sectional view showing the operation of the driving force transmission device when turning left in the middle and low vehicle speed range, and FIG. 9 is a longitudinal section showing the operation of the driving force transmission device when turning right in the middle and low vehicle speed region. FIG.

  As shown in FIG. 8, when the vehicle turns to the left in the middle and low vehicle speed range, a control signal from the electronic control unit ECU is input to the left shift solenoid valve 108L, and the output side of the left shift solenoid valve 108L is connected to the oil passage L4. Switch to connect. The clutch piston 51 is actuated by the oil supplied through the oil passage L4, and the carrier member 11 is coupled to the housing 20 by engaging the left clutch CL and stops rotating.

  At that time, the right output shaft 9R provided integrally with the right front wheel WFR and the left output shaft 9L (planetary gear 8 of the differential mechanism D) provided integrally with the left front wheel WFL are the second sun gear 18, Since it is connected via the second pinion 14, the first pinion 13 and the first sun gear 17, the rotational speed NR of the right front wheel WFR is increased with respect to the rotational speed NL of the left front wheel WFL in the relationship of the following equation. The

NR / NL = (Zd / Zc) × (Za / Zb)
= 1.154 (1)
As described above, when the rotational speed NR of the right front wheel WFR is increased with respect to the rotational speed NL of the left front wheel WFL, as shown by the hatched arrows in FIG. Part of the WFL torque is transmitted to the right front wheel WFR, which is the outer turning wheel, and it is possible to assist the left turn of the vehicle and improve the turning performance.

  Instead of stopping the carrier member 11 by the left clutch CL, the rotation force of the right front wheel WFR is rotated in accordance with the degree of deceleration by appropriately adjusting the engaging force of the left clutch CL to reduce the rotation speed of the carrier member 11. The speed NR can be increased, and an appropriate torque can be transmitted from the left front wheel WFL that is the inner turning wheel to the right front wheel WFR that is the outer turning wheel.

  On the other hand, as shown in FIG. 9, when the vehicle turns right in the middle and low vehicle speed range, a control signal from the electronic control unit ECU is input to the right shift solenoid valve 108R, and the output side of the right shift solenoid valve 108R It switches so that it may be connected with the path | route L5. The clutch piston 57 is actuated by the oil supplied through the oil passage L5, and the third sun gear 19 is coupled to the housing 20 by engaging the right clutch CR to stop the rotation.

  As a result, the third pinion 15 meshing with the third sun gear 19 revolves and rotates, the rotational speed of the carrier member 11 is increased with respect to the rotational speed of the right output shaft 9R, and the rotational speed NL of the left front wheel WFL is: The rotational speed NR of the right front wheel WFR is increased according to the following equation.

NL / NR = {1- (Ze / Zf) × (Zb / Za)}
÷ {1- (Ze / Zf) × (Zd / Zc)}
= 1.156 (2)
As described above, when the rotational speed NL of the left front wheel WFL is increased with respect to the rotational speed NR of the right front wheel WFR, as indicated by the hatched arrows in FIG. Part of the WFR torque can be transmitted to the left front wheel WFL, which is the outer turning wheel. Also in this case, if the rotational speed of the carrier member 11 is increased by appropriately adjusting the engaging force of the right clutch CR, the rotational speed NL of the left front wheel WFL is set to the rotational speed of the right front wheel WFR corresponding to the speed increase. The speed is increased with respect to the speed NR, and an appropriate torque is transmitted from the right front wheel WFR, which is the inner turning wheel, to the left front wheel WFL, which is the outer turning wheel, to assist the right turning of the vehicle and improve the turning performance. it can.

  At that time, instead of stopping the third sun gear 19 with the right clutch CR, the engaging force of the right clutch CR is adjusted as appropriate to reduce the rotational speed of the third sun gear 19, so that the left front wheel corresponds to the degree of deceleration. The rotation speed NL of the WFL is increased with respect to the rotation speed NR of the right front wheel WFR, and appropriate torque can be transmitted from the right front wheel WFR that is the turning inner wheel to the left front wheel WFL that is the turning outer wheel.

  As will be understood by comparing the equations (1) and (2), the teeth of the first pinion 13, the second pinion 14, the third pinion 15, the first sun gear 17, the second sun gear 18, and the third sun gear 19 By setting the number as described above, the acceleration rate from the left front wheel WFL to the right front wheel WFR (about 1.154) and the acceleration rate from the right front wheel WFR to the left front wheel WFL (about 1.156) are substantially the same. It can be.

  FIG. 12 is an explanatory diagram showing a time chart according to a comparative example in which the left and right clutches are switched simultaneously.

FIG. 12A shows a switching control signal output from the electronic control unit ECU to the right shift solenoid valve 108R, and shows the switching timing of the right shift solenoid valve 108R between the on state and the off state. Yes. In FIG. 12A, the vertical axis also indicates the command pressure b output from the electronic control unit ECU to the right shift solenoid valve 108R.
FIG. 12B is a switching control signal output from the electronic control unit ECU to the left shift solenoid valve 108L, and shows the switching timing of the left shift solenoid valve 108L between the on state and the off state. Yes. In FIG. 12B, the vertical axis also indicates the command pressure a output from the electronic control unit ECU to the left shift solenoid valve 108L.
FIG. 12C shows the command pressure set based on the control signal from the electronic control unit ECU and the output pressure regulated by the linear solenoid valve 106.
FIG. 12D shows the hydraulic pressure (actual pressure) of oil detected by the right hydraulic pressure sensor 110R and supplied to the right clutch CR to actually operate the clutch piston 57.
FIG. 12E shows the oil pressure (actual pressure) of oil detected by the left oil pressure sensor 110L and supplied to the left clutch CL to actually operate the clutch piston 51.

  In the comparative example, for example, when the vehicle is switched from the right turning state to the left turning state, the engagement of the right clutch CR in which the oil path connected to the right shift solenoid valve 108R is switched from the oil path L5 to the oil drain path L7. The release and the engagement of the left clutch CL that switches the oil passage connected to the left shift solenoid valve 108L from the oil discharge passage L6 to the oil passage L4 are performed simultaneously (see FIGS. 12A and 12B). An overshoot occurs in which the pressure (actual pressure) of oil supplied to the left clutch CL is greater than the left shift solenoid valve command pressure a (target pressure) (see FIG. 12E).

  That is, when the oil passage L5 of the right shift solenoid valve 108R is closed and the right clutch CR is disengaged, and at the same time the oil passage L4 of the left shift solenoid valve 108L is opened and the left clutch CL is engaged, the left and right shifts are performed. Due to the influence of the oil pressure (residual pressure) of the oil remaining in the linear solenoid valve 106 disposed on the upstream side of the solenoid valves 108L and 108R, a hydraulic overshoot occurs in the engaged left clutch CL.

  The residual pressure of the oil remaining in the linear solenoid valve 106 is not reduced so much and is higher than the command pressure a (target hydraulic pressure) for the left clutch CL, and the relatively high pressure remaining in the linear solenoid valve 106 is high. When oil is supplied to the left clutch CL, it is presumed that an overshoot that temporarily becomes high pressure occurs when the operation of the clutch piston 51 of the left clutch CL is started (at the time of rising).

  In the comparative example, when this overshoot occurs, for example, the torque difference (driving force difference) between the left front wheel WFL and the right front wheel WFR becomes larger than necessary, and the vehicle bends more than necessary (turns too much). ). Further, when the comparative example is applied to, for example, a hydraulic control circuit of an automatic transmission (not shown), there is a problem that an impact at the time of shifting (shift shock) increases due to the occurrence of the overshoot.

FIG. 10 is an explanatory diagram showing a time chart according to the present embodiment.
In addition, since description of each figure in Fig.10 (a)-(e) is the same as that of Fig.12 (a)-(e), the detailed description is abbreviate | omitted.

  First, in the right turn state and the right shift solenoid valve 108R is turned on and the right clutch CR is engaged, the electronic control unit ECU outputs an off signal to the right shift solenoid valve 108R. The oil passage connected to the output side of the right shift solenoid valve 108R is switched from the oil passage L5 to the oil discharge passage L7 in the off state (see FIG. 10A). At that time, the electronic control unit ECU does not simultaneously output an ON signal to the left shift solenoid valve 108L.

  Subsequently, the electronic control unit ECU monitors the actual pressure of the oil output from the right hydraulic pressure sensor 110R and supplied to the right clutch CR, and the actual pressure of the right clutch CR is k times the left shift solenoid valve command pressure a ( When the pressure value is lower than the pressure value k · a), an ON signal is output to the left shift solenoid valve 108L to turn on the left shift solenoid 108L (see FIG. 10B). When the left shift solenoid valve 108L is turned on, the oil path connected to the output side of the left shift solenoid valve 108L is switched from the oil discharge path L6 to the oil path L4. As a result, the clutch piston 51 of the left clutch CL is actuated by the oil pressure of the oil supplied from the left shift solenoid valve 108L via the oil passage L4, and the left clutch CL can be engaged.

  As described above, in the present embodiment, when the left and right clutches (hydraulic clutches) CL and CR to be engaged are switched, the target oil pressure (right shift solenoid valve command pressure b) of the right clutch CR to be disengaged is changed. When the target hydraulic pressure (left shift solenoid valve command pressure a) of the left clutch CL to be engaged after switching is larger (a <b), the oil passage connected to the right clutch CR to be disengaged is drained. After the connection to the road L7, the actual hydraulic pressure value (actual pressure) of the right clutch CR detected by the right hydraulic pressure sensor 110R is released to the vicinity of the target value of the left clutch CL to be engaged after switching. At the time of the drop, the left shift solenoid valve 108L is controlled to switch so that the oil passage connected to the left clutch CL engaged after the switching is connected to the oil passage L4.

  Therefore, in the present embodiment, unlike the comparative example described above, it is possible to suppress the occurrence of an overshoot that temporarily increases the pressure when the operation of the clutch piston 51 of the left clutch CL starts (at the time of startup). As a result, in the present embodiment, it is possible to prevent the vehicle from being bent more than necessary, or the occurrence of problems in the comparative example such as a shift shock.

  The constant k may be set within a range of about 1.1 to 1.5 by experiment or simulation. That is, in the present embodiment, not when the actual pressure of the right clutch CR decreases below the left shift solenoid valve command pressure a, but the actual pressure of the right clutch CR is k times (k · a) the left shift solenoid valve command pressure a. When the pressure value falls below this value, an ON signal is output to the left shift solenoid valve 108L to turn on the left shift solenoid valve 108L. As described above, in this embodiment, when the left shift solenoid valve 108L is turned on when the pressure is slightly higher than the left shift solenoid valve command pressure a, the response delay of the left clutch CL can be prevented. it can.

  In other words, when the left shift solenoid valve 108L corresponding to the newly engaged left clutch CL is turned on, the output pressure of the linear solenoid valve 106 is set to the target pressure (left shift) of the left clutch CL to be newly engaged. The output pressure of the linear solenoid valve 106 has decreased to the target pressure (left shift solenoid valve command pressure a) by setting the timing to a pressure slightly lower than the solenoid valve command pressure a) (near the target value). This is because, compared to when the left shift solenoid valve 108L is sometimes turned on, the engagement delay of the left clutch CL to be newly engaged can be suppressed.

  Further, in the present embodiment, the actual pressure of the right clutch CR to be disengaged is detected by the existing right hydraulic sensor 110R, and the left shift solenoid valve 108L is turned on based on the detection signal of the right hydraulic sensor 110R. For example, when the hydraulic pressure on the output side of the linear solenoid valve 106 is detected and the timing is set, a hydraulic sensor for detecting the hydraulic pressure on the output side of the linear solenoid valve 106 is required separately. The number of parts increases.

  Furthermore, in the present embodiment, the electronic control unit ECU outputs an off signal for turning off the right shift solenoid valve 108R and an on signal for turning on the left shift solenoid valve 108L delayed by a predetermined time. However, for example, after outputting the ON signal and the OFF signal at the same time, wait for a detection signal from the right hydraulic pressure sensor 110R using a delay circuit (not shown). The left shift solenoid valve 108L may be switched from the off state to the on state when the time is delayed by a predetermined time.

  When switching the left and right clutches (hydraulic clutches) CL and CR to be engaged, the target hydraulic pressure (right shift solenoid valve command pressure b) of the right clutch CR to be disengaged is switched, contrary to the above. When the target hydraulic pressure (left shift solenoid valve command pressure a) of the left clutch CL to be engaged after that is smaller (a> b), the above control by the electronic control unit ECU is not performed, The clutches CL and CR may be switched simultaneously.

Next, another embodiment of the present invention is shown in FIG. In addition, since description of each figure in Fig.11 (a)-(e) is the same as that of Fig.10 (a)-(e), the detailed description is abbreviate | omitted.
In this other embodiment, the electronic control unit ECU does not depend on the detection signal from the right hydraulic pressure sensor 110R, and after the electronic control unit ECU turns off the right shift solenoid valve 108R, a predetermined time delay (elapse of delay time T). Therefore, the left shift solenoid valve 108L is in an on state, which is different from the above embodiment.

  The delay time T is set to a predetermined value. In this case, the electronic control unit ECU gradually increases the oil temperature based on the oil temperature detection signal output from the oil temperature sensor 104 by the electronic control unit ECU. It is good to set so that it may become small. This is because the oil temperature increases, the oil viscosity decreases, and the pressure drop rate of the oil remaining in the linear solenoid valve 106 increases.

67 Oil pump (hydraulic pump)
106 Linear solenoid valve (regulating valve)
108L Left shift solenoid valve (switching valve)
108R Right shift solenoid valve (switching valve)
CL Left clutch (hydraulic clutch)
CR Right clutch (hydraulic clutch)
ECU Electronic control unit (switching control means)
L4, L5 oil passage (hydraulic supply passage)
L6, L7 Oil drainage (hydraulic oil drainage)
E Engine (drive source)

Claims (2)

A driving force transmission device that selectively engages a plurality of hydraulic clutches and switches a driving force transmission path for transmitting a driving force of a driving source,
A hydraulic pump for generating hydraulic pressure supplied to each hydraulic clutch;
A pressure regulating valve for regulating the hydraulic pressure discharged from the hydraulic pump to a target hydraulic pressure;
An oil passage provided corresponding to each of the plurality of hydraulic clutches and connected to the hydraulic clutch is switched between a hydraulic supply passage to which the hydraulic pressure regulated by the pressure regulating valve is supplied and a hydraulic drain oil passage. Switching valve to be connected,
When switching the hydraulic clutch to be engaged, if the target hydraulic pressure of the hydraulic clutch to be disengaged is greater than the target hydraulic pressure of the hydraulic clutch to be engaged after switching, the hydraulic clutch is connected to the hydraulic clutch to be disengaged. Switching control of the switching valve so that an oil passage connected to a hydraulic clutch to be engaged after switching is connected to the hydraulic supply passage with a time delay after connecting the oil passage to the hydraulic oil discharge passage. Switching control means for
A driving force transmission device comprising: A driving force transmission device that selectively engages a plurality of hydraulic clutches and switches a driving force transmission path for transmitting a driving force of a driving source,
A hydraulic pump for generating hydraulic pressure supplied to each hydraulic clutch;
A pressure regulating valve for regulating the hydraulic pressure discharged from the hydraulic pump to a target hydraulic pressure;
An oil passage provided corresponding to each of the plurality of hydraulic clutches and connected to the hydraulic clutch is switched between a hydraulic supply passage to which the hydraulic pressure regulated by the pressure regulating valve is supplied and a hydraulic drain oil passage. Switching valve to be connected,
A hydraulic sensor provided corresponding to each of the plurality of hydraulic clutches for detecting an actual hydraulic pressure value of each hydraulic clutch;
When switching the hydraulic clutch to be engaged, if the target hydraulic pressure of the hydraulic clutch to be disengaged is greater than the target hydraulic pressure of the hydraulic clutch to be engaged after switching, the hydraulic clutch is connected to the hydraulic clutch to be disengaged. Until the actual hydraulic pressure value of the hydraulic clutch to be disengaged detected by the hydraulic sensor is changed to the vicinity of the target value of the hydraulic clutch to be engaged after switching. Switching control means for switching and controlling the switching valve so that an oil passage connected to a hydraulic clutch engaged after the switching is connected to the hydraulic pressure supply passage at the time of lowering;
A driving force transmission device comprising:

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