JP2006056512A - Vehicular right and left driving force distributing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicular right and left driving force distributing device capable of enhancing the workability during the assembly and improving the assemblability to a vehicle by using an outer rotating body of a hydraulic motor also as one axis arm, and reducing the number of components. <P>SOLUTION: The input side of a housing 1 is formed as a stepped cylindrical input housing part 2, and the output side is formed as a stepped cylindrical output housing part 3 extending in the right-to-left direction. A propulsion shaft 4 to be rotated by an engine is provided on the input housing part 2, and a differential case 6 of a differential mechanism 5 provided in the output housing part 3 is rotated by the propulsion shaft 4 via an input gear 4A and a ring gear 7. The driving force is distributed and transmitted to right and left axis arms 16, 17 by the differential mechanism 5. A motor case 19 of a hydraulic motor 18 is constituted as a stepped bottomed cylindrical body extending in the axial direction to a sleeve 14 side of the differential mechanism 5, and is also used for the axis arm 17 by the motor case 19. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a vehicle left and right driving force distribution device that is preferably used to control the distribution of driving force to, for example, left and right wheel axles, and more particularly to a configuration that positively distributes driving force using a hydraulic motor. The present invention relates to a vehicle left-right driving force distribution device.

  In general, a vehicle such as a four-wheeled vehicle is provided with a differential gear device including a differential mechanism such as a differential gear between left and right wheel shafts serving as driving wheels in order to improve cornering performance, for example. Is distributed to the left and right wheel shafts by the differential gear device.

  However, the drive force distribution control by such a differential gear device only distributes the drive force from the engine to the left and right using the reaction force received by the left and right wheels from the road surface. For this reason, for example, when a wheel slips on a low μ road surface having a reduced friction coefficient due to freezing or the like, stable drive force distribution control may be difficult.

  Therefore, in order to stably distribute the driving force of the vehicle to the left and right wheel axles, an auxiliary motor such as a hydraulic motor is incorporated in the differential gear device, and the driving force suitable for the steering operation of the driver is Control that actively distributes to the right wheel shaft has been proposed (see, for example, Patent Documents 1 and 2).

Japanese Patent Laid-Open No. 3-50028 JP-A-10-329572

  A vehicle left / right driving force distribution device according to this type of prior art includes a housing, an input shaft provided on the input side of the housing and driven to rotate by the engine of the vehicle, and provided on the output side of the housing from the input shaft. A differential mechanism composed of a differential gear that distributes and transmits the driving force to the left and right wheel axles, and pressure oil is supplied and discharged from the outside provided together with the differential mechanism on the output side of the housing It is composed of a reversible hydraulic motor or the like that applies a relative rotational force between the left and right wheel shafts.

  When hydraulic oil is supplied and discharged from an external hydraulic source according to the driving state of the vehicle, the hydraulic motor applies a relative rotational force between the left and right wheel shafts by the oil pressure at this time. By controlling the distribution of the driving force, for example, by actively generating a yaw moment in the vehicle, the running stability of the vehicle can be ensured.

  By the way, in the above-described prior art, since the left and right wheel shafts and the hydraulic motor are configured as separate members, it is necessary to provide the wheel shaft by penetrating the center side of the hydraulic motor in the axial direction. There is a problem that the number of points increases and it is difficult to improve workability during assembly.

  Further, the wheel shaft provided through the hydraulic motor has an axial intermediate portion inserted into the inner peripheral side of the hydraulic motor, for example, a cylinder block (inner rotating body), and both are connected by means such as a spline. . One end side of the wheel shaft receives drive torque from the input shaft on the differential mechanism side, and the other end side protrudes outside the housing and is connected to the wheel.

  For this reason, the wheel shaft provided through the hydraulic motor needs to be formed as a long shaft, and transmits a large driving torque from one end side (differential mechanism side) to the wheel on the other end side. Therefore, it is necessary to make the shaft diameter large and to have a sturdy structure, and there is a problem that the layout is limited when it is provided through the hydraulic motor.

  In addition, since the wheel shaft is penetrated into the hydraulic motor, it is difficult to separate the hydraulic fluid for maintaining the differential mechanism side in a lubricated state and the hydraulic fluid of the hydraulic motor, and the hydraulic motor is supplied to and discharged from the hydraulic motor. There is a problem that a part of the pressure oil (working oil) must be used as the lubricating oil on the differential mechanism side, and the lubrication performance cannot always be improved.

  Furthermore, in the prior art, for example, a plurality of pressure oil supply / discharge passages are formed in the hydraulic motor in order to supply and discharge the pressure oil sequentially in a plurality of cylinders provided in a cylinder block of the hydraulic motor. The passage block is provided separately from the cylinder block. However, since this passage block has a structure that protrudes greatly on one side of the wheel shaft in the axial direction, the housing of the device has an asymmetric shape on the left and right with respect to the input shaft, and the left and right wheel shafts are respectively There is a problem in that there are restrictions on the layout when connecting to other wheels.

  The present invention has been made in view of the above-described problems of the prior art, and an object of the present invention is to make the outer rotary body of a hydraulic motor also serve as one wheel shaft and eliminate the need for a long and sturdy large-diameter shaft member. Another object of the present invention is to provide a left / right driving force distribution device for a vehicle that can improve the workability during assembly by reducing the number of parts.

Another object of the present invention, the left relative to the input shaft housing of the device, right can be formed in substantially symmetrical, left, freedom of layout design right wheel axis on connecting the respective wheel It is an object of the present invention to provide a left / right driving force distribution device for a vehicle that can increase the degree of assembly and improve the ease of assembly to the vehicle.

  In order to solve the above-described problems, the present invention provides a housing, an input shaft provided on the input side of the housing and driven to rotate by a vehicle engine, and driven from the input shaft provided on the output side of the housing. A differential mechanism that distributes and transmits force to the left and right wheel axles, and the left and right wheel axles provided on the output side of the housing together with the differential mechanism by supplying and discharging pressure oil from the outside The present invention is applied to a left / right driving force distribution device for a vehicle including a reversible hydraulic motor that applies a relative rotational force therebetween.

A feature of the configuration adopted by the invention of claim 1 is that the hydraulic motor includes an outer rotating body that is rotatably provided on the output side of the housing, and a hydraulic oil that is rotatably provided in the outer rotating body. made of an inner rotary member rotates relative to the outer rotary member by the supply and discharge, before Kihidari wheel shaft of one of the right wheel axis, configured to rotate integrally with the outer rotary member of said hydraulic motor And the other wheel shaft is connected to the inner rotating body of the hydraulic motor so as to be integrally rotatable .

As described above, according to the first aspect of the present invention, one of the left and right wheel shafts is rotated integrally with the outer rotating body of the hydraulic motor, and the other wheel shaft rotates inward of the hydraulic motor. Since it is configured to be connected to the body so that it can rotate integrally, one wheel shaft that rotates integrally with the outer rotating body and the inner rotation when the hydraulic motor is driven to rotate by supplying and discharging pressure oil to the hydraulic motor from the outside. Rotational forces in opposite directions can be applied to the other wheel shaft connected to the body, and appropriate driving force distribution can be performed for the left and right wheel shafts. Moreover, it is not necessary to use as the wheel axis a robust shaft an elongate penetrating the hydraulic motor as in the prior art, it is possible to improve the workability during assembly by reducing the number of parts.

  Hereinafter, a left and right driving force distribution device for a vehicle according to an embodiment of the present invention will be described in detail with reference to FIGS. 1 to 5 of the accompanying drawings.

  In the figure, reference numeral 1 denotes a housing of the driving force distribution device. The housing 1 is a stepped cylindrical input housing portion 2 located on the input side, and is integrated with the input housing portion 2 located on the output side. The output housing part 3 is provided with a stepped cylindrical output housing part 3 extending in the left and right directions. The output housing part 3 includes a cylindrical body part 3A located in the center as shown in FIG. It is generally composed of stepped cylindrical cover portions 3B and 3C provided on both the left and right sides of 3A.

  Further, the output housing part 3 is provided with a stepped cylinder part 3D between the cover part 3C and positioned inside the trunk part 3A, and a hydraulic pressure described later is provided between the cover part 3C and the stepped cylinder part 3D. A motor 18 is rotatably arranged. The stepped cylinder portion 3D extends in the axial direction from the cover portion 3C side toward the cover portion 3B side, and the tip side of the stepped cylinder portion 3D is reduced in diameter so as to avoid interference with the input gear 4A described later. Is formed.

  Reference numeral 4 denotes a propulsion shaft as an input shaft rotatably provided in the input housing portion 2 of the housing 1, and the propulsion shaft 4 is connected to a crankshaft (not shown) of an engine mounted on the vehicle. It is rotationally driven by. Further, the propulsion shaft 4 is provided with an input gear 4A on the tip end side extending into the body portion 3A of the output housing portion 3, and the input gear 4A meshes with a ring gear 7 described later.

  A differential mechanism 5 is located on the cover 3B side and is rotatably provided in the output housing 3. The differential mechanism 5 is composed of, for example, a planetary gear device and the like, and a differential case 6 that forms an outer shell thereof. A ring gear 7 that meshes with the input gear 4A is fixed on the outer peripheral side of the differential case 6 (hereinafter referred to as the differential case 6) with a bolt or the like. The differential case 6 is rotationally driven by the propulsion shaft 4 via the input gear 4A and the ring gear 7, and the driving force at this time is distributed to the left and right wheel shafts 16 and 17 by the sun gear 13 and the carrier 8 described later. Is transmitted.

  Here, as shown in FIGS. 3 and 4, the differential mechanism 5 includes an internal gear 6A formed on the inner peripheral side of the differential case 6 over the entire periphery, and a carrier 8 provided in the differential case 6 so as to be relatively rotatable. And a plurality of planetary gears 10, 10... That are rotatably supported by the carrier 8 via the support shaft 9 and meshed with the internal gear 6 </ b> A, and the support shaft 11 on the carrier 8 so as to mesh with each planetary gear 10. Are planetary gears 12, 12,... Rotatably supported via the sun gears 13 and sun gears 13 that mesh with the planetary gears 12 and can rotate relative to the carrier 8.

  The sun gear 13 is splined so as to rotate integrally with a wheel shaft 16 which will be described later, and the rotation of the differential case 6 (for example, the rotation in the direction of arrow A in FIG. 4) is via two planetary gears 10 and 12. This is transmitted to the sun gear 13 as rotation in the same direction. Further, the revolution of the planetary gears 10 and 12 is transmitted to the carrier 8 via the support shafts 9 and 11, whereby the carrier 8 also rotates in the same direction as the differential case 6.

  When the vehicle travels straight, the rotational force on the differential case 6 side is evenly distributed to the sun gear 13 and the carrier 8 via the planetary gears 10 and 12, and the sun gear 13 and the carrier 8 are left at the same rotational speed. The right wheel shafts 16 and 17 are rotationally driven.

  Further, when the steering operation (turning) of the vehicle, the sun gear 13 and the left and right wheels (not shown) are rotated so that one of the wheel shafts 16 and 17 rotates faster than the other due to a reaction force received from the road surface. The rotational force on the differential case 6 side is transmitted to the carrier 8 with different rotation ratios. As a result, the wheel on the inside of the turn has a relatively low rotational speed, and the wheel on the outside of the turn has a higher rotational speed, thereby exhibiting a differential function that enhances the cornering performance of the vehicle.

  14 is a stepped sleeve that constitutes a part of the differential mechanism 5. The sleeve 14 is fixed to the end face side of the carrier 8 by using bolts 15 (see FIG. 4) as shown in FIG. 8 is led out to the motor case 19 (wheel shaft 17) described later. And the spline 14A is formed in the inner peripheral side of the sleeve 14, This spline 14A is couple | bonded with the cylindrical connection part 22B of the other side case 22 mentioned later.

  Reference numerals 16 and 17 denote left and right wheel shafts, and the left wheel shaft 16 is formed by using a single shaft member. The right wheel shaft 17 includes a motor case 19 and a joint flange 24 described later. The wheel shaft 16 is inserted into the output housing portion 3 at one end and becomes a small-diameter spline shaft portion 16A. The spline shaft portion 16A is connected to the center side of a cylinder block 25 described later in a non-rotating state. Yes.

  Further, the wheel shaft 16 has a joint flange portion 16B having a large diameter at the other end projecting out of the output housing portion 3, and another spline shaft portion 16C and an intermediate portion between the joint flange portion 16B and the spline shaft portion 16A. A circular seal step 16D is formed. The spline shaft portion 16C is inserted into the inner peripheral side of the sun gear 13 so as to rotate integrally with the sun gear 13, and transmits the rotation of the sun gear 13 to the joint flange portion 16B side of the wheel shaft 16. .

For this reason, the wheel shaft 16 is formed with a relatively large diameter from the joint flange portion 16B to the spline shaft portion 16C, and has sufficient rigidity to transmit a large driving force to the external wheel. On the other hand, the portion extending from the position of the spline shaft portion 16C to the spline shaft portion 16A on the tip side only needs to transmit a relatively small driving force generated in a cylinder block 25 of the hydraulic motor 18 to be described later, and therefore has a relatively small diameter. Is formed. Further, a seal member 38, which will be described later, is in sliding contact with the outer peripheral side of the seal step portion 16D to prevent leakage and mixing of the oil as will be described later.

  Reference numeral 18 denotes a reversible hydraulic motor positioned on the cover portion 3C side and rotatably provided in the output housing portion 3. The hydraulic motor 18 is composed of, for example, a radial piston hydraulic motor, and will be described later. 19, a cylinder block 25, a piston 27, a passage block 32, and the like.

  Further, the hydraulic motor 18 is arranged side by side in the left and right directions in the output housing portion 3 with respect to the differential mechanism 5, and the passage block 32 is placed between the cylinder block 25 and the differential mechanism 5. ing. The hydraulic motor 18 is rotated relative to the left and right wheel shafts 16 and 17 by supplying and discharging pressure oil from a hydraulic pump 40 described later to relatively rotate the motor case 19 and the cylinder block 25. It gives power.

  A motor case 19 is rotatably provided in the output housing portion 3 and constitutes an outer rotating body of the hydraulic motor 18. The motor case 19 is formed as a covered cylindrical body as shown in FIGS. The one side case 20 in which the output shaft portion 20B is integrally formed on the center side of the lid portion 20A, the cam ring 21 and the other side case 22, and the cam ring 21 between the one side case 20 and the other side case 22 A plurality of bolts 23, 23,... (See FIG. 5) are sandwiched and integrated.

  The entire motor case 19 including the one-side case 20, the cam ring 21, and the other-side case 22 has a covered stepped cylinder extending in the axial direction from the position of a cylindrical connecting portion 22B described later to the position of the output shaft portion 20B. The right wheel shaft 17 is formed together with the outer joint flange 24. In this case, the output shaft portion 20B of the one-side case 20 protrudes outward from the cover portion 3C of the output housing portion 3, and the joint flange 24 is splined to the protruding end side.

  Here, as shown in FIG. 5, the cam ring 21 of the motor case 19 is formed with a cam surface 21A on the inner peripheral side, and the cam surface 21A receives a driving force from the piston 27 via rollers 29 described later. By doing so, a relative rotational force in the direction of arrow A or B in FIG. 5 is generated between the motor case 19 and the cylinder block 25.

  Further, as shown in FIG. 3, the other case 22 is formed as a stepped cylindrical body having a diameter reduced to approximately two steps, and the cylinder block 25 is sandwiched between the one case 20 and the axial direction toward the differential mechanism 5 side. And a cylindrical connecting portion 22B extending from the distal end side of the cylindrical extending portion 22A toward the inner peripheral side of the sleeve 14. The cylindrical connecting portion 22B is configured such that the outer peripheral side engages with the spline 14A of the sleeve 14 from the inside to rotate the motor case 19 (wheel shaft 17) integrally with the sleeve 14 of the differential mechanism 5.

  Reference numeral 25 denotes a cylinder block that constitutes an inner rotating body of the hydraulic motor 18. The cylinder block 25 is formed as a rotor formed of a flat stepped cylindrical body, and is provided in the motor case 19 so as to be rotatable via a plurality of bearings. It has been. Further, a fitting hole 25A into which the spline shaft portion 16A of the wheel shaft 16 is fitted in a non-rotating state is formed as a bottomed hole on the center side of the cylinder block 25.

  Here, a plurality of radially extending cylinders 26, 26,... Are formed in the cylinder block 25 as shown in FIG. 5, and pistons 27, 27,. It is fitted.

  Further, the cylinder block 25 is formed with a plurality of oil passages 28, 28,... Individually communicating with the cylinders 26, and the oil passages 28 are sequentially communicated with supply / discharge passages 33A, 33B of the passage block 32 described later. Thus, pressure oil from the outside is supplied to and discharged from each cylinder 26. Each piston 27 reciprocates in the cylinder 26 by pressure oil supplied to and discharged from the cylinder 26 to generate a rotational force of the hydraulic motor 18.

  , 29,... Are rollers provided rotatably at the projecting end of each piston 27 via a support shaft 30, and 31, 31,... Urge each roller 29 toward the cam surface 21 A of the cam ring 21. Each spring 31 is disposed between the cylinder 26 and the piston 27 and constantly urges the piston 27 in a direction in which the piston 27 protrudes from the cylinder 26. The roller 29 slides along the cam surface 21A of the cam ring 21 to compensate for smooth relative rotation between the cylinder block 25 and the cam ring 21 (motor case 19).

  32 is a passage block as a valve member for supplying and discharging pressure oil into and from each cylinder 26 of the cylinder block 25. The passage block 32 is formed as a stepped cylinder as shown in FIG. For example, a knock pin, a key groove or the like is provided in the cylindrical extension portion 22A of the motor case 19 (other side case 22) located on the outer peripheral side in a non-rotating state. The passage block 32 rotates integrally with the motor case 19 and holds the cylinder block 25 so as to be rotatable relative to the lid portion 20A of the one-side case 20 and the like.

  Further, a plurality of supply / discharge passages 33A, 33B are formed in the passage block 32 at regular intervals in the circumferential direction, and the supply / discharge passages 33A, 33B are staggered on a virtual circle concentric with the wheel shaft 16. Are alternately arranged. The end face side of the passage block 32 that is in sliding contact with the end face of the cylinder block 25 constitutes a switching valve portion that alternately communicates the supply / discharge passages 33A and 33B with the oil passages 28 of the cylinder block 25.

  Further, on the outer peripheral side of the passage block 32, annular oil grooves 34A and 34B communicating with the respective supply / discharge passages 33A and 33B are formed, and the annular oil grooves 34A and 34B are separated from each other in the axial direction of the passage block 32. Arranged. The annular oil grooves 34 </ b> A and 34 </ b> B are provided with oil holes 35 </ b> A and 35 </ b> B formed in the cylindrical extending portion 22 </ b> A of the other case 22 and supply / discharge ports 36 </ b> A and 36 </ b> B formed in the stepped cylindrical portion 3 </ b> D of the output housing portion 3. The pressure oil from the supply / discharge ports 36A, 36B is guided to the supply / discharge passages 33A, 33B, respectively.

  37 is a seal member provided between the stepped cylinder portion 3D of the output housing portion 3 and the motor case 19 of the hydraulic motor 18, and the seal member 37 is constituted by a double lip seal or the like as shown in FIG. The other side case 22 is mounted between the cylindrical extending portion 22A and the stepped cylindrical portion 3D with a tightening margin. The seal member 37 separates, for example, lubricating oil on the differential mechanism 5 side and pressure oil (operating oil) on the hydraulic motor 18 side between the output housing portion 3 and the motor case 19, and these oil liquids. Prevent leakage and mixing.

  38 is a seal member provided between the seal step portion 16D of the wheel shaft 16 and the motor case 19, and the seal member 38 is also constituted by a double lip seal or the like, and the cylindrical extension portion 22A of the other case 22 Attached between the seal step 16D with a tightening margin. The seal member 38 separates, for example, the lubricating oil on the differential mechanism 5 side and the hydraulic oil on the hydraulic motor 18 side from each other between the wheel shaft 16 and the motor case 19, and leaks and mixes these fluids. It is to prevent.

  Next, 39 is a reservoir in which hydraulic oil is stored, and 40 is a hydraulic pump that constitutes a hydraulic pressure source together with the reservoir 39. The hydraulic pump 40 is rotationally driven by the propulsion shaft 4 shown in FIG. Is supplied and discharged to the pipelines 41A and 41B as high-pressure oil. And the front end side of pipe line 41A, 41B is connected to the supply / discharge port 36A, 36B formed in the stepped cylinder part 3D of the output housing part 3 as shown in FIG. 2, FIG.

  Reference numeral 42 denotes a directional control valve provided in the middle of the pipelines 41A and 41B. The directional control valve 42 is composed of, for example, a four-port, three-position electromagnetic directional control valve, and controls the direction of the pressure oil supplied to and discharged from the hydraulic motor 18. Switching means for switching is configured. The direction control valve 42 has solenoid parts 42A and 42B on both the left and right sides, and a control signal is output to the solenoid parts 42A and 42B from an external control unit (not shown).

  As a result, the directional control valve 42 is switched from the neutral position (A) to the left and right switching positions (B) and (C) as shown in FIG. 1, and the hydraulic pump is operated at the switching positions (B) and (C). The direction of the pressure oil supplied and discharged from the hydraulic motor 18 from 40 is switched. Further, while the directional control valve 42 is held in the neutral position (A), the hydraulic motor 18 is substantially stopped by stopping the supply and discharge of the pressure oil, and the rotation output is invalidated.

  43 is a variable pressure relief valve, and the relief valve 43 constitutes hydraulic control means for variably controlling the discharge pressure (pressure of the hydraulic oil) of the hydraulic pump 40. The relief valve 43 has a solenoid part 43A for pressure adjustment, and variably controls the relief set pressure according to the current value or pulse duty of the control signal output from the control unit to the solenoid part 43A. is there.

  The left / right driving force distribution device for a vehicle according to the present embodiment has the above-described configuration. Next, the operation thereof will be described.

  First, when the vehicle engine is driven to rotate, the rotation output is transmitted to the differential case 6 of the differential mechanism 5 via the propulsion shaft 4, and the rotation of the differential case 6 (for example, the rotation in the direction of arrow A in FIG. 4) is 2. This is transmitted as rotation in the same direction to the sun gear 13 via the planetary gears 10 and 12. Further, the revolutions of the planetary gears 10 and 12 are transmitted to the carrier 8 of the differential mechanism 5 through the support shafts 9 and 11, whereby the carrier 8 also rotates in the same direction as the differential case 6.

  When the vehicle travels straight, the rotational force on the differential case 6 side is evenly distributed to the sun gear 13 and the carrier 8 via the planetary gears 10 and 12, and the sun gear 13 and the carrier 8 have the same rotational speed. Since the left and right wheel shafts 16 and 17 are rotationally driven, the vehicle is driven to travel through the left and right wheels.

  In addition, when steering the vehicle (turning), the sun gear 13 and the carrier 8 have a differential case so that one of the wheel shafts 16 and 17 rotates faster than the other due to the reaction force received by the left and right wheels from the road surface. The 6-side rotational force is transmitted with different rotation ratios, so that the wheels on the inside of the turn have a relatively low rotational speed, and the wheels on the outside of the turn have a higher rotational speed to improve the cornering performance of the vehicle. be able to.

  By the way, since the driving force distribution to the left and right wheel shafts 16 and 17 by the differential mechanism 5 is control depending on the reaction force received from the road surface by the left and right wheels, for example, when a slip occurs. In some cases, the function of distributing the driving force is lost and the running stability of the vehicle cannot always be improved.

  In such a case, a control signal is output from the control unit to the directional control valve 42 and the relief valve 43 in accordance with detection signals from various sensors (not shown) for detecting the driving state of the vehicle. By switching 42 from the neutral position (A) to the switching position (B), the pressure oil from the hydraulic pump 40 is supplied to and discharged from the hydraulic motor 18 in the output housing section 3 via the pipelines 41A and 41B. .

  The hydraulic motor 18 in the output housing portion 3 supplies and discharges the pressure oil into each cylinder 26 in the cylinder block 25 through the supply / discharge passages 33A and 33B of the passage block 32 and the oil passages 28 and the like. The piston 27 is reciprocated in each cylinder 26, whereby the motor case 19 of the hydraulic motor 18 and the cylinder block 25 rotate relative to each other.

  As a result, between the left and right wheel shafts 16, 17, rotational forces due to the relative rotation of the motor case 19 and the cylinder block 25 are applied in opposite directions and applied from the propulsion shaft 4 to the differential mechanism 5. The driving force is positively distributed to the left and right wheel shafts 16 and 17 according to the rotational force of the hydraulic motor 18. And by the driving force distribution at this time, for example, a yaw moment can be positively generated in the vehicle, and the running stability of the vehicle can be ensured.

  Here, in the present embodiment, one of the left and right wheel shafts 16, 17 is constituted by the motor case 19 of the hydraulic motor 18 and the joint flange 24, and the differential mechanism 5. The other case 22 of the motor case 19 is splined to the sleeve 14 at the position of the cylindrical connecting portion 22B, and the output shaft portion 20B integrally formed with the lid portion 20A of the one side case 20 is connected to the output housing portion 3. A spline connection is made to the joint flange 24 at the outer position.

  As a result, the motor case 19 serving as the outer rotating body of the hydraulic motor 18 can also be used as a part of the wheel shaft 17, and there is no need to prepare a long wheel shaft separately from the hydraulic motor as in the prior art. For this reason, the number of parts of the driving force distribution device can be reduced, and workability during assembly can be improved.

  Further, since the wheel shaft 17 can also be used by the motor case 19 of the hydraulic motor 18, the cylinder block 25 serving as the inner rotating body of the hydraulic motor 18 does not need to form the fitting hole 25A as an axial through hole, for example. For example, it is only necessary to fit the tip end portion (spline shaft portion 16A) formed on the small diameter of the wheel shaft 16 in a non-rotating state.

  As a result, the cylinder block 25 of the hydraulic motor 18 can be formed with a relatively small outer diameter, and the outer diameter of the motor case 19 can also be reduced. For this reason, the hydraulic motor 18 can be accommodated in the output housing part 3 in a compact manner, and the entire apparatus can be reduced in size and weight.

  Further, with respect to the wheel shaft 16, by forming a portion extending from the joint flange portion 16B to the spline shaft portion 16C with a relatively large diameter, it is possible to give sufficient rigidity to transmit a large driving force to an external wheel. . A portion extending from the position of the spline shaft portion 16C to the spline shaft portion 16A on the tip side only needs to transmit a relatively small driving force generated in the cylinder block 25 of the hydraulic motor 18, and is therefore formed to have a relatively small diameter. This eliminates the need for the wheel shaft 16 to be formed as a long shaft with a large diameter and a strong overall length.

  Further, the motor case 19 is formed as a covered stepped cylindrical body so as to share a part of the wheel shaft 17, and in the other case 22 of the motor case 19, the cylinder block 25, the differential mechanism 5 side, 1 and accommodates the passage block 32, the projecting dimensions L1 and L2 of the left and right wheel shafts 16 and 17 with respect to the center of the propulsion shaft 4 as shown in FIG. Can be set to equal dimensions.

  For this reason, the output housing part 3 can be formed in a substantially symmetrical shape on the left and right with respect to the input housing part 2 (propulsion shaft 4), and the left and right wheel axles 16 and 17 have a high degree of freedom with respect to the respective wheels. It can be connected. As a result, it is possible to solve problems such as layout restrictions when the left / right driving force distribution device is mounted on a vehicle as in the prior art.

  Further, since the wheel shaft 17 is also used in the motor case 19 of the hydraulic motor 18 and it is not necessary to form an axial through hole or the like in the cylinder block 25, only two seal members 37 and 38 are used. The lubricating oil on the differential mechanism 5 side and the hydraulic oil on the hydraulic motor 18 side can be easily separated, and these oil liquids can be well prevented from leaking and mixing.

  As a result, part of the pressure oil (hydraulic oil) supplied to and discharged from the hydraulic motor 18 does not need to be used as the lubricating oil on the differential mechanism 5 side as in the prior art, and the differential mechanism 5 side has a dedicated function. Gear oil or the like can be supplied as a lubricating oil to improve the lubricating performance. In addition, for the hydraulic oil supplied to and discharged from the hydraulic motor 18, it is possible to extend the life and improve the maintainability by using a dedicated oil liquid.

  Therefore, according to the present embodiment, since the wheel shaft 17 is also used as the motor case 19 of the hydraulic motor 18, it is not necessary to use a long and sturdy large-diameter shaft member as in the prior art, and the number of parts is reduced. The workability at the time of assembly can be improved by reducing Further, the lubricating oil used for the differential mechanism 5 and the like can be well separated from the hydraulic oil on the hydraulic motor 18 side, and the lubricating performance can be improved.

  Further, when the propulsion shaft 4 is used as a reference, the overhanging dimensions L1 and L2 of the left and right wheel shafts 16 and 17 can be set to substantially equal dimensions, so that the left and right wheel shafts 16 and 17 are connected to the respective wheels. The degree of freedom in layout design can be increased when connecting to the vehicle, and the assemblability when mounted on the vehicle can be improved.

  In the above embodiment, the case where the radial piston type hydraulic motor 18 is used has been described as an example. However, the present invention is not limited to this. For example, the swash plate type hydraulic motor and the trochoid type hydraulic motor are used. For example, various types of hydraulic motors may be employed.

  Further, in the above embodiment, the case where the differential mechanism 5 is constituted by the planetary gears 10, 12 and the like has been described as an example, but instead, for example, Japanese Patent Laid-Open No. 3-50028, The differential mechanism may be configured by using a bevel gear or the like as in the prior art described in Kaihei 10-329572.

1 is a longitudinal sectional view showing a left / right driving force distribution device for a vehicle according to an embodiment of the present invention. It is a longitudinal cross-sectional view which expands and shows the output housing part side in FIG. It is a principal part enlarged view of FIG. It is sectional drawing which expands and shows a differential mechanism from arrow IV-IV in FIG. It is sectional drawing which expands and shows a hydraulic motor from the arrow VV direction in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Housing 2 Input housing part 3 Output housing part 4 Propulsion shaft (input shaft)
5 Differential mechanism 6 Differential case 7 Ring gears 16, 17 Wheel shaft 18 Hydraulic motor 19 Motor case (outer rotating body)
20 One side case 20A Lid portion 20B Output shaft portion 21 Cam ring 22 Other side case 22A Cylindrical extending portion 25 Cylinder block (inner rotating body)
26 Cylinder 27 Piston 32 Passage Block 33A, 33B Supply / Discharge Passage 37, 38 Seal Member 39 Reservoir 40 Hydraulic Pump (Hydraulic Source)
42 Directional control valve 43 Relief valve

Claims (6)

A housing, an input shaft provided on the input side of the housing and driven to rotate by a vehicle engine, and a driving force provided on the output side of the housing distributed from the input shaft to the left and right wheel shafts for transmission And a reversible mechanism for providing a relative rotational force between the left and right wheel shafts by supplying and discharging pressure oil from the outside provided on the output side of the housing together with the differential mechanism. In a vehicle left-right driving force distribution device including a hydraulic motor,
The hydraulic motor includes an outer rotating body that is rotatably provided on the output side of the housing, and an inner side that is rotatably provided in the outer rotating body and rotates relative to the outer rotating body by supplying and discharging the pressure oil. A left and right driving force distribution device for a vehicle, comprising: a rotating body, wherein the outer rotating body also serves as a part of one of the left and right wheel shafts.   2. The left / right driving force distribution device for a vehicle according to claim 1, wherein the other wheel shaft of the left and right wheel shafts is connected to an inner rotating body of the hydraulic motor so as to be integrally rotatable.   The differential mechanism and the hydraulic motor are provided side by side in the left and right directions on the output side of the housing with respect to the input shaft, and the outer rotating body of the hydraulic motor includes the differential mechanism and the inner rotating body. The left and right driving force distribution device for a vehicle according to claim 1 or 2, wherein a passage block is provided which is provided between the housing and the inner rotating body and has a supply / discharge passage through which pressure oil is circulated.   The outer rotating body of the hydraulic motor is formed as a stepped cylindrical body with a lid, and is formed of a motor case in which an output shaft portion that is a part of the one wheel shaft is integrally formed on the center side of the lid portion. 4. The vehicle according to claim 3, wherein the rotating body includes a plurality of cylinders to which the pressure oil is supplied and discharged, and is constituted by a cylinder block that is rotationally driven in the motor case by a piston provided in each cylinder. Left and right driving force distribution device.   The motor case has a cylindrical extending portion extending toward the differential mechanism side at a position facing the lid portion in the axial direction across the cylinder block, and the passage block supplies pressure oil to each cylinder block. The left and right driving force distribution device for a vehicle according to claim 4, wherein the vehicle is provided with a rotation stop state in the cylindrical extension portion for sequentially switching into and out of the cylinder.   A seal member is provided on the output side of the housing between the differential mechanism and the hydraulic motor, and the seal member separates the lubricating oil on the differential mechanism side and the hydraulic oil on the hydraulic motor side from each other. The left and right driving force distribution device for a vehicle according to claim 1, 2, 3, 4, or 5 configured as described above.

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