JP2010101333A - Driving force distributing device for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a driving force distribution device for a vehicle, wherein an oil pump to supply hydraulic pressure to a torque distribution mechanism is operated even when one of right and left wheels runs idle with a differential mechanism. <P>SOLUTION: This driving force distribution device for a vehicle includes the planetary gear differential mechanism D, and the torque distribution mechanism A for distributing torque to the right and left wheels. The oil pump 67 for generating hydraulic pressure to operate the clutches CL, CR of the torque distribution mechanism A is driven by transmitting the rotation of the final driven gear 3 of the differential case 33 of the differential mechanism D thereto via a pump driving gear 75. Thus, the oil pump 67 can be operated even when one of the right and left wheels contacts a road surface having a small friction coefficient and runs idle, and the clutches CL, CR of the torque distribution mechanism A is operated without trouble to exhibit a torque distributing function. Since the oil pump 67 is driven utilizing an existing final driven gear 3, an increase in the number of parts can be suppressed without requiring a special gear. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a vehicle driving force distribution device that distributes torque of a drive source from a transmission to left and right wheels via a differential mechanism and a torque distribution mechanism.

Such a vehicle driving force distribution device is known from Patent Document 1 below. This vehicle driving force distribution device includes a differential mechanism composed of a double pinion planetary gear mechanism and a torque distribution mechanism composed of a planetary gear mechanism using a special triple pinion member between left and right axles. The torque is distributed between the left and right wheels by selectively restraining one sun gear or carrier member of the torque distribution mechanism with a pair of clutches and forcibly restricting the rotational speed ratio between the left and right axles. It has become.
Japanese Patent No. 3104157

  By the way, in the case where the oil pump that generates hydraulic pressure for operating the pair of clutches of the torque distribution mechanism is driven by one of the pair of output shafts of the differential mechanism, the output on the opposite side of the one output shaft When the wheel connected to the shaft idles, there is a problem that the function of the torque distribution mechanism is lost because the oil pump becomes inoperable.

  The present invention has been made in view of the above-described circumstances, and an object of the present invention is to enable an oil pump that supplies hydraulic pressure to a torque distribution mechanism even when one of left and right wheels is idled by a differential mechanism.

  In order to achieve the above object, according to the first aspect of the present invention, in a vehicle driving force distribution device that distributes torque of a drive source from a transmission to left and right wheels via a differential mechanism and a torque distribution mechanism. A drive force distribution for a vehicle characterized in that an oil pump that generates hydraulic pressure for operating a clutch of a torque distribution mechanism is driven by a final driven gear that is provided in a differential case of a differential mechanism and meshes with a final drive gear of a transmission A device is proposed.

  The left clutch CL and the right clutch CR of the embodiment correspond to the clutch of the present invention, the engine E of the embodiment corresponds to the drive source of the present invention, and the front wheels WFL, WFR of the embodiment correspond to the present invention. Corresponds to the wheel.

  According to the configuration of the first aspect, the oil pump that generates the hydraulic pressure that operates the clutch of the torque distribution mechanism is driven by the final driven gear that is provided in the differential case of the differential mechanism and meshes with the final drive gear of the transmission. Even when one of the wheels contacts with the road surface having a small friction coefficient and idles, the oil pump can be operated, and the clutch of the torque distribution mechanism can be operated to exert the torque distribution function without any trouble. In addition, since the driving force is transmitted to the oil pump using the final driven gear provided in the differential case, a special gear for driving the oil pump is unnecessary, and the increase in the number of parts can be suppressed.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

  1 to 7 show an embodiment of the present invention. FIG. 1 is a diagram showing the overall configuration of a front engine / front drive vehicle, FIG. 2 is a skeleton diagram showing the structure of a driving force distribution device, and FIG. FIG. 4 is an enlarged view of part 4 of FIG. 3, FIG. 5 is an enlarged view of part 5 of FIG. 3, and FIG. 6 is a driving force at the time of turning left in the middle and low vehicle speed range. FIG. 7 is a diagram illustrating the operation of the distribution device, and FIG. 7 is a diagram illustrating the operation of the driving force distribution device during a right turn in the middle and low vehicle speed range.

  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 E mounted horizontally at the front of the vehicle body, and a differential mechanism D and a torque distribution mechanism A are disposed at the rear of the engine E and transmission M. 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.

  As shown in FIGS. 2 and 3, the differential mechanism D for transmitting the driving force from the final driven gear 3 that meshes with the final drive gear 2 provided on the transmission output shaft 1 extending from the transmission M is a double pinion type planetary gear mechanism. A ring gear 4 formed integrally with the final driven gear 3, a sun gear 5 coaxially disposed inside the ring gear 4, an outer planetary gear 6 meshing with the ring gear 4, and an inner planetary gear 7 meshing with the sun gear 5. , And a planetary carrier 8 that supports them in 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. Planetary carrier 8 that functions as the other output element is connected to left front wheel WFL via left output shaft 9L and left axle AFL.

  The torque distribution mechanism A that distributes the driving force between the left and right front wheels WFL, WFR is a planetary gear mechanism, and the carrier member 11 is rotatably supported on the outer periphery of the right output shaft 9R and is 90 ° circumferentially. 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 the four pinion shafts 12 arranged at intervals.

  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 meshes with the second pinion 14. Further, the third sun gear 19 rotatably supported on the outer periphery of the right output shaft 9R meshes with the third pinion 15.

  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 in the embodiment is 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 can be coupled to the housing 20 of the torque distribution mechanism A via the right clutch CR, and the rotation speed of the carrier member 11 is increased by the engagement of the right clutch CR. Further, the carrier member 11 can be coupled 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 U calculates the engine torque Te, the engine speed Ne, the vehicle speed V, and the steering angle θ based on a predetermined program, and controls the operation of the left clutch CL and the right clutch CR.

  Next, the structures of the differential mechanism D and the torque transmission mechanism A will be described in more detail with reference to FIGS.

  The differential case 33 constituting the outer shell of the differential mechanism D accommodated between the left transmission case 31 and the right transmission case 32 is formed by connecting the first case 34 and the second case 35 with bolts 36. 36, the final driven gear 3 is fastened together. 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 final drive gear 2 through the final driven 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 so as to be relatively rotatable and is splined to the left carrier half 8L. The 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, 8R are connected to each other by outer pinion pins 39 and inner pinion pins 40, and outer planetary gears 6 are rotatably supported by outer pinion pins 39 to inner pinion pins 40. Inner planetary gears 7 are rotatably supported.

  The torque distribution mechanism A is configured by connecting a left case 41 and a right case 42 with bolts 43..., And the left end of the half shaft 10 supported therein via a ball bearing 44 is the right end of the left output shaft 9R. Spline combined. A sleeve 46 supported by a left case 41 via a ball bearing 45 is fitted to the outer periphery of the left portion of the second sun gear 18 formed integrally with the half shaft 10 so as to be relatively rotatable, and at the right end thereof. The first sun gear 17 is splined. The right end of the sleeve 47, which is fitted to the outer periphery of the right output shaft 9R so as to be relatively rotatable and whose left end is splined to the right carrier half 8R of the differential mechanism D, is splined to the left end of the sleeve 46. Accordingly, the first sun gear 17 is connected to the right carrier half 8R via the sleeves 46 and 47.

  The left clutch CL disposed between the left end of the carrier member 11 and the left case 41 is a friction disposed between a clutch inner 48 provided on the carrier member 11 and a clutch outer 49 provided on the left case 41. The engagement member 50 is configured by a clutch piston 51 that hydraulically engages the friction engagement member 50 and a return spring 52 that urges the clutch piston 51 in the disengagement direction.

  A third sun gear 19 is supported on the outer circumference of the right half shaft 10 of the second sun gear 18 via a ball bearing 53 so as to be relatively rotatable. The right 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 on the right case 42. Are hydraulically engaged, and a return spring 58 that urges the clutch piston 57 in the disengagement direction.

  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 is apparent from FIG. 4, the pump unit 61 that supplies oil to the torque distribution mechanism A includes a pump body 63, a separator plate 64, and a pump cover 65 coupled by bolts 62. It is fixed to the left case 41 of the torque distribution mechanism A with bolts 66.

  A trochoid oil pump 67 housed in a pump chamber 63 a formed in the pump body 63 is configured by meshing the outer teeth of the inner rotor 69 with the inner teeth of the outer rotor 68. A rotary shaft 71 coupled to the inner rotor 69 by a pin 70 is supported by the pump body 63 and the pump cover 65 by ball bearings 73 and 74, and the rotary shaft 71 protrudes to the left from the pump body 63 via the seal member 72. The pump drive gear 75 provided at the front end of the differential gear meshes with the final driven gear 3 provided on the outer periphery of the first case 35 of the differential case 33. The separator plate 64 and the pump cover 65 are formed 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 operation of the embodiment of the present invention having the above configuration will be described.

  With the torque distribution mechanism A having the above-described configuration, the carrier member 11 is engaged with the housing by engaging the left clutch CL in response to a command from the electronic control unit U when the vehicle is turning left in the middle and low vehicle speed range as shown in FIG. 20 to stop rotation. At this time, the right output shaft 9R integral with the right front wheel WFR and the left output shaft 9L integral with the left front wheel WFL (that is, the planetary carrier 8 of the differential mechanism D) are the second sun gear 18, the second pinion 14, Since it is connected via 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 according to the following equation.

NR / NL = (Zd / Zc) × (Za / Zb)
= 1.154 (1)
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 described above, the left front wheel WFL that is the turning inner wheel is indicated by the hatched arrow in FIG. Is transmitted to the right front wheel WFR, which is the outer turning wheel, and the left turning of the vehicle is assisted to improve the turning performance.

  Instead of stopping the carrier member 11 with the left clutch CL, if the rotational speed of the carrier member 11 is reduced by appropriately adjusting the engagement force of the left clutch CL, the rotational speed NR of the right front wheel WFR is reduced according to the deceleration. The speed is increased with respect to the rotation speed NL of the left front wheel WFL, and an arbitrary torque can be transmitted from the left front wheel WFL that is the turning inner wheel to the right front wheel WFR that is the turning outer wheel.

  On the other hand, as shown in FIG. 7, the third sun gear 19 is coupled to the housing 20 by engaging the right clutch CR in response to a command from the electronic control unit U when turning right in the middle and low vehicle speed range of the vehicle. Stop rotation. As a result, the third pinion 15 meshing with the third sun gear 19 revolves and rotates, the speed of the carrier member 11 is increased with respect to the speed of the right output shaft 9R, and the speed NL of the left front wheel WFL is The speed is increased in accordance with the following equation with respect to the rotational speed NR of the front wheel WFR.

NL / NR = {1- (Ze / Zf) × (Zb / Za)}
÷ {1- (Ze / Zf) × (Zd / Zc)}
= 1.156 (2)
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 described above, the right front wheel WFR that is the turning inner wheel is indicated by the hatched arrow in FIG. A part of the torque can be transmitted to the left front wheel WFL which is a turning outer wheel. Also in this case, if the rotational speed of the carrier member 11 is increased by appropriately adjusting the engagement force of the right clutch CR, the rotational speed NL of the left front wheel WFL is changed to the rotational speed NR of the right front wheel WFR according to the increased speed. On the other hand, it is possible to increase the speed and transmit an arbitrary torque from the right front wheel WFR which is the inner turning wheel to the left front wheel WFL which is the outer turning wheel, thereby assisting the right turning of the vehicle and improving the turning performance.

  Also in this case, instead of stopping the third sun gear 19 by the right clutch CR, if the rotational force of the third sun gear 19 is reduced by appropriately adjusting the engagement force of the right clutch CR, the left front wheel WFL is correspondingly reduced. Is increased with respect to the rotational speed NR of the right front wheel WFR, and an arbitrary 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 is clear from the comparison of the expressions (1) and (2), 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 determined. By setting 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 made substantially equal. Can do.

  By the way, for example, when only the left front wheel WFL slips in mud etc., the torque of the engine E is transmitted only to the left front wheel WFL by the action of the differential mechanism D, and the right front wheel WFR rotates. It will stop. Therefore, when the oil pump 67 is configured to be driven by the right output shaft 9R or the half shaft 10 of the differential mechanism D, the oil pump 67 becomes inoperable and the left and right clutches CL and CR of the torque distribution mechanism A are turned off. It cannot be engaged. Conversely, when the oil pump 67 is configured to be driven by the left output shaft 9L of the differential mechanism D, when the right front wheel WFR slips, the oil pump 67 becomes inoperable and the torque distribution mechanism A The left and right clutches CL and CR cannot be engaged.

  However, in the present embodiment, the oil pump 67 is driven by the final driven gear 3 provided in the differential case 33 of the differential mechanism D that always rotates when the vehicle is traveling, so even if one of the left and right front wheels WFL, WFR slips. The oil pump 67 can be operated without hindrance, and the hydraulic pressure can be supplied to the left and right clutches CL and CR of the torque distribution mechanism A without interruption.

  Therefore, by engaging the left clutch CL and the right clutch CR at a predetermined slip ratio, respectively, the left axle AFL and the right axle AFR can be integrated so that they cannot be rotated relative to each other, and the differential limiting function can be exhibited. Torque can be transmitted to the left and right front wheels WFL, WFR to allow escape from mud.

  Moreover, since the oil pump 67 is driven using the existing final driven gear 3 that is always provided to transmit the driving force from the transmission M to the operating mechanism D, a special gear for driving the oil pump 67 is added. It becomes unnecessary to suppress the increase in the number of parts.

  The embodiments of the present invention have been described above, but various design changes can be made without departing from the scope of the present invention.

  For example, in the embodiment, the torque distribution mechanism A distributes the torque between the left and right front wheels WFL, WFR, but may distribute the torque between the left and right rear wheels WRL, WRR.

  The drive source of the vehicle is not limited to the engine E, and may be an electric motor.

Diagram showing overall configuration of front engine / front drive vehicle Skeleton diagram showing the structure of the driving force distribution device The figure which shows the concrete structure of a driving force distribution device 4 enlarged view of FIG. 5 enlarged view of FIG. The figure which shows the action of the driving force distribution device at the time of the left turn in the middle and low vehicle speed range The figure which shows the operation of the driving force distribution device at the time of the right turn in the middle and low vehicle speed range

Explanation of symbols

A Torque distribution mechanism CL Left clutch (clutch)
CR Right clutch (clutch)
D Differential mechanism E Engine (drive source)
M Transmission WFL Front wheels (wheels)
WFR Front wheel (wheel)
2 Final drive gear 3 Final driven gear 33 Differential case 67 Oil pump

Claims (1)

In the vehicle driving force distribution device that distributes the torque of the drive source (E) from the transmission (M) to the left and right wheels (WFL, WFR) via the differential mechanism (D) and the torque distribution mechanism (A),
An oil pump (67) that generates hydraulic pressure for operating the clutches (CL, CR) of the torque distribution mechanism (A) is provided in the differential case (33) of the differential mechanism (D) to provide a final drive of the transmission (M). The vehicle driving force distribution device is driven by a final driven gear (3) meshing with the gear (2).

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