阅读说明：本技术 能够二级限制差动的差动装置 (Differential device capable of two-stage limiting differential motion ) 是由 福田宏伦 于 2017-12-04 设计创作，主要内容包括：差动装置具备输入部件和输出齿轮,并具备：一边允许差动一边介入上述转矩的传递的齿轮组；限制上述差动的第一离合器；在轴向上与上述第一离合器邻接并为了按压上述第一离合器而沿轴向可动的第一压板；为了朝向上述第一离合器按压上述第一压板而与上述第一压板邻接的第一凸轮机构；若啮合则禁止上述差动的第二离合器；在轴向上与上述第二离合器邻接并为了使上述第二离合器啮合而沿轴向可动的第二压板；以及能够从第一位置经由第二位置至第三位置地进行旋转运动的驱动盘,该驱动盘具备按压部件,为了使上述第一凸轮机构一起从上述第一位置旋转到上述第二位置,并从上述第二位置至上述第三位置允许上述第一凸轮机构产生旋转差,按压部件与上述第一凸轮机构结合,并且驱动盘与上述第二压板的组合构成使上述第二离合器啮合的第二凸轮机构。(The differential device is provided with an input member and an output gear, and is provided with: a gear group which allows differential motion and intervenes in the transmission of the torque; a first clutch for limiting the differential motion; a first pressure plate axially adjacent to the first clutch and movable in an axial direction for pressing the first clutch; a first cam mechanism adjacent to the first pressure plate for pressing the first pressure plate toward the first clutch; a second clutch for inhibiting the differential operation if the clutch is engaged; a second pressure plate which is adjacent to the second clutch in the axial direction and is movable in the axial direction for engaging the second clutch; and a drive plate that is capable of rotating from a first position to a third position via a second position, the drive plate including a pressing member that is coupled to the first cam mechanism such that the first cam mechanism is rotated together from the first position to the second position and a rotational difference in the first cam mechanism is allowed from the second position to the third position, and a combination of the drive plate and the second pressure plate constitutes a second cam mechanism that engages the second clutch.)

1. A differential device is characterized by comprising:

an input member that receives torque and rotates around a shaft;

a gear train including an output gear rotatable about the shaft, the gear train being coupled to the input member so as to allow a differential motion from the input member to the output gear and to transmit the torque;

a first clutch coupled to the input member and the output gear to limit the differential;

a first pressure plate that is adjacent to the first clutch in an axial direction and is movable in the axial direction to press the first clutch;

a first cam mechanism that is adjacent to the first pressure plate so as to press the first pressure plate toward the first clutch;

a second clutch which, when engaged, drivingly couples the output gear to the input member;

a second pressure plate that is adjacent to the second clutch in an axial direction and is movable in the axial direction to engage the second clutch; and

and a drive plate that is capable of rotating from a first position to a third position via a second position, wherein the drive plate includes a pressing member that is coupled to the first cam mechanism such that the first cam mechanism is rotated together from the first position to the second position and a rotational difference of the first cam mechanism is allowed from the second position to the third position, and wherein a combination of the drive plate and the second pressure plate constitutes a second cam mechanism that engages the second clutch.

2. The differential device of claim 1,

the second clutch includes first clutch teeth that are engaged with the input member in the circumferential direction and are movable in the axial direction, and second clutch teeth that are engaged with the output gear and mesh with the first clutch teeth, and the second clutch teeth are formed integrally with the first pressure plate.

3. The differential device of claim 1,

the second presser plate includes a leg portion extending toward the drive disc, the drive disc includes a cam surface against which the leg portion abuts, and the cam surface is dimensioned so that the leg portion is pressed toward the second clutch by the second presser plate in association with the rotational movement from the second position to the third position.

4. The differential device of claim 1,

the first cam mechanism includes a cam plate drivingly engaged with the pressing member and a cam ball that rolls on the cam plate in accordance with the rotational movement to generate a pressing force in an axial direction.

5. The differential device of claim 1,

the input member includes a housing that houses the gear train, the first cam mechanism, the second cam mechanism, and the drive plate are disposed outside the housing, and the housing includes a first through hole that connects the first cam mechanism and the first clutch, and a second through hole that connects the second cam mechanism and the second clutch.

6. The differential device of claim 5,

the second clutch includes an arm portion fitted into the second through hole, and a side surface of the arm portion and a side surface of the second through hole are inclined in a circumferential direction in order to convert rotation of the housing into a force for holding engagement of the second clutch.

7. The differential device of claim 1,

the first clutch includes a first friction plate drivingly coupled to the input member and a second friction plate drivingly coupled to the output gear, and the first friction plate and the second friction plate are arranged to be pressed by the first pressure plate to frictionally restrict rotation of the first friction plate and the second friction plate relative to each other.

Technical Field

The following disclosure relates to a differential device for a vehicle capable of two-stage limitation of a differential, and more particularly, to a differential device capable of limiting a differential in a first stage and locking in a second stage.

Background

In an automobile, since the left and right axles do not necessarily rotate at the same speed, it is necessary to allow a differential motion therebetween. In order to transmit torque to both axles while allowing differential motion, a differential device is used.

To avoid this, some differential devices are provided with a mechanism for limiting the differential, an example of which is a limited slip differential (L SD) using a friction clutch, and an electronic control L SD., which is a combination of a means for applying a pressing force to the friction clutch and an electronic device for controlling the means, is also used as a pressing means, and hydraulic pressure and a cam mechanism are proposed.

Further, a so-called free-running differential is capable of disconnecting and connecting a differential device to a propeller shaft, and is used for switching between two-wheel drive and four-wheel drive, for example, a friction clutch and a pressing means are sometimes used for such disconnection and connection, and a device in which an electronic control L SD and a free-running differential are combined, which is provided with two independent sets of a friction clutch and a pressing means, is also proposed, and related technology is disclosed in patent document 1.

Disclosure of Invention

The friction clutch starts to slip when receiving a torque exceeding a threshold value determined by the pressing force, and therefore is suitable for limiting the differential motion, but is not suitable for use in locking the differential device. The engaged clutch is suitable for use in locking a differential device, but cannot be used for limiting the differential because it does not slip. If the two types of clutches and the separate drive units are present, a differential device capable of freely selecting the differential limitation and the locking can be realized, but this significantly complicates the configuration of the device. The complex construction is of course disadvantageous both in terms of reliability and weight.

The following disclosure relates to a device that achieves both differential limiting and locking with only one actuator.

According to one aspect, a differential device includes: an input member that receives torque and rotates around a shaft; a gear train including an output gear rotatable about the shaft, the gear train being coupled to the input member so as to allow a differential motion from the input member to the output gear and to transmit the torque; a first clutch coupled to the input member and the output gear to limit the differential; a first pressure plate that is adjacent to the first clutch in an axial direction and is movable in the axial direction to press the first clutch; a first cam mechanism that is adjacent to the first pressure plate so as to press the first pressure plate toward the first clutch; a second clutch which, when engaged, drivingly couples the output gear to the input member; a second pressure plate that is adjacent to the second clutch in an axial direction and is movable in the axial direction to engage the second clutch; and a drive plate that is capable of rotating from a first position to a third position via a second position, wherein the drive plate includes a pressing member that is coupled to the first cam mechanism such that the first cam mechanism is rotated together from the first position to the second position and a rotational difference of the first cam mechanism is allowed from the second position to the third position, and wherein a combination of the drive plate and the second pressure plate constitutes a second cam mechanism that engages the second clutch.

Drawings

Fig. 1 is a front sectional view of a differential device according to an embodiment.

Fig. 2A is a partially exploded perspective view of the differential device mainly showing the first and second clutches.

Fig. 2B is a partially exploded perspective view of the differential device mainly showing the first and second cam mechanisms and the drive plate.

Fig. 3 is a top view of the drive plate and cam plate as viewed in the axial direction.

Fig. 4 is a partial sectional view of the first cam mechanism taken in the circumferential direction.

Fig. 5 is a partial sectional view of the second cam mechanism taken in the circumferential direction.

Fig. 6A is a partial front sectional view of the differential device mainly showing the first and second clutches and the first and second cam mechanisms, and shows a state before the first clutch is engaged but before the second clutch is engaged.

Fig. 6B is a partial front sectional view of the differential device mainly showing the first and second clutches and the first and second cam mechanisms, and shows a state after the second clutch is engaged.

Fig. 7 is a partial sectional view of the differential device mainly showing the through-hole of the second clutch and the housing, and shows a state where the arm portion is in contact with the wall surface of the through-hole.

Detailed Description

Several exemplary embodiments are described below with reference to the accompanying drawings. In the following description and claims, unless otherwise specified, an axis refers to a rotation axis of a differential device, an axial direction refers to a direction parallel to the axis, and a radial direction refers to a direction perpendicular to the axis. The axis of rotation is typically, but not necessarily, coincident with the axis of rotation of the cam mechanism, drive plate. For convenience of explanation, the right and left are distinguished, but such distinction is not limited to the embodiment.

The present invention is applicable to any gear device that generates a differential motion between an input member and an output gear while transmitting torque therebetween, such as a plane gear type or a planetary gear type.

Referring mainly to fig. 1, the differential device generally includes: a housing 1 as an input member; a differential gear set 3 for transmitting torque while allowing differential operation; a first clutch 5 for limiting differential motion; a second clutch 7 for locking differential; and an actuator 9 for actuating the clutch.

The housing 1 houses not only the differential gear set 3 but also an input member that receives torque from the engine/motor and rotates around the shaft C. The housing 1 is divided into a plurality of parts and the inside is opened, so that it is possible to facilitate assembling of various parts, for example, the main body 11 and the cover 13. For example, a flange that protrudes outward in the radial direction may be provided to facilitate coupling of the main body 11 and the cover 13 to each other, and this flange may also be used for coupling of a ring gear that receives torque. Of course, other configurations may be utilized in conjunction with one another, and the acceptance of torque may also be undertaken by other portions of the housing 1.

For example, the main body 11 of the housing 1 has a through hole for coupling the shaft 15 to the circumferential surface thereof, and the shaft 15 is fixed to the main body 11 by a pin or the like. The cover 13 of the housing 1 has through holes 17 and 19 for connecting the clutches 5 and 7 and the actuator 9, for example, on the side surface thereof.

The differential gear set 3 is basically provided with a plurality of pinion gears 31 and side gears 33 and 35 meshing with the pinion gears 31. The pinion 31 is supported by the shaft 15 so as to be rotatable about the shaft, and receives torque from the housing 1 via the shaft 15.

The side gears 33 and 35 are output gears having a spline structure for coupling to the axles, respectively, and outputting torque to both axles. That is, the differential gear set 3 allows differential motion and transmits torque from the housing 1 as an input member to the side gears 33 and 35 as output gears via meshing in the gear set.

One of the side gears 33 and 35, for example, the boss 35B of the left side gear 35, is preferably extended in the axial direction for coupling with the first clutch 5, and in particular, for engagement with the inner plate 53 and the pressure plate 55 described below in the circumferential direction.

Referring to fig. 2A in conjunction with fig. 1, the first clutch 5 is preferably a friction clutch including at least one pair of friction plates that rub against each other, for example, a multiple-plate clutch including a plurality of outer plates 51, a plurality of inner plates 53, and a pressure plate 55. Although only one pair is visible in fig. 2A, a plurality of pairs of outer plates 51 and inner plates 53 are alternately arranged in the axial direction, the outer plates 51 are engaged with the housing 1 by soldering or the like, and the inner plates 53 are engaged with the bosses 35B by soldering or the like. The plates 51, 53, and 55 are slightly movable in the axial direction, and the pressure plate 55 can press the plates 51 and 53 while being adjacent to each other in the axial direction. When the pressure plate 55 slightly moves toward the plates 51 and 53 to apply a pressing force to the plates 51 and 53, the plates 51 and 53 frictionally brake the side gear 35 to the housing 1, that is, restrict the differential motion.

The housing 1 also accommodates a clutch member 75 therein and is movable in the axial direction. The first clutch teeth 71 are cut out of the clutch member 75 on the surface facing the pressure plate 55, and the second clutch teeth 73 are engaged with each other to form the second clutch 7. The second clutch teeth 73 may be formed as a separate member from the pressure plate 55, or may be formed integrally with the pressure plate 55. In any case, such a separate member or the pressure plate 55 is engaged with the boss 35B of the side gear 35 by a solder piece or the like.

A plurality of leg portions 77 axially extend from a surface of the clutch member 75 facing in a direction opposite to the first clutch teeth 71 in an axisymmetric manner, and as shown in fig. 7 in particular, the plurality of leg portions 77 are respectively fitted into and engaged with the through holes 19 of the cover 13. The end of each leg may face outward through the through hole 19 and be coupled to the ring 107 outside the housing 1 by a bolt or the like. The ring member 107 is used for connection with the second cam mechanism 101 described below.

When the clutch member 75 moves in the axial direction toward the pressure plate 55 and the clutch teeth 71 and 73 are engaged with each other, the second clutch 7 drivingly couples the side gear 35 to the housing 1 via engagement with the cover 13 by the leg portion 77, that is, prohibits differential operation (lock differential gear). To facilitate the release of the engagement, a return spring may be interposed between the ring 107 and the cover 13.

Referring to fig. 2B in conjunction with fig. 1 and 2A, the actuator 9 is roughly provided with a first cam mechanism 91 that drives the first clutch 5, a second cam mechanism 101 that drives the second clutch 7, and a drive plate 95 that operates the cam mechanisms.

The first cam mechanism 91 can be a cam mechanism that generates a large pressing force. The first cam mechanism 91 of the illustrated example is substantially provided with a cam plate 81 rotatable around an axis, a plurality of cam balls 83 arranged axisymmetrically, and a rotation-stopping back pressure plate 85. The cam plate 81 and the counter plate 85 are each, for example, substantially circular or disc-shaped, and the cam ball 83 is sandwiched between these members and can roll. Instead of the balls, rollers such as cylindrical rollers or truncated cones that can roll may be provided, or cam projections formed on either one or both of the cam plate 81 and the counter plate 85 may be provided.

The cam plate 81 has a plurality of cam surfaces 81F corresponding to the cam balls 83, respectively, and each cam surface 81F has a bottom extending in the circumferential direction and gradually inclining in the circumferential direction. In addition or instead, the counter-pressure plate 85 may also have a cam surface, respectively. The cam plate 81 is further provided with, for example, a pair of clamps 81G for engagement with the drive plate 95. Since the clamp 81G is engaged with the driving disk 95 itself or a pressing member 97 described below, the clamp is rotationally driven by the driving disk 95.

As best shown in fig. 4, cam plate 81 induces rotational motion R if driven by drive disk 95_DWhen the cam ball 83 rolls on the cam surface 81F and rises along the inclined bottom thereof, an axial pressing force F is generated on the back pressure plate 85₁。

Referring back to fig. 1, 2A, and 2B, referring mainly to fig. 2B, the intermediate member 37 can be used to intervene between the first cam mechanism 91 and the first clutch 5. The medium member 37 is, for example, substantially annular, and includes a plurality of axially symmetric projections 37P facing the first clutch 5, and the projections 37P are adjacent to the pressure plate 55 through the through hole 17 of the cover 13. In order to equalize the pressing force of the protrusion 37P and to absorb the relative rotation before being restricted, an interposition member 103 may be interposed between the protrusion 37P and the pressure plate 55 in the housing 1. The insert 103 is, for example, a thrust bearing and/or a ring plate. Further, the thrust bearing/annular plate 105 may be interposed between the medium member 37 and the first cam mechanism 91.

The actuator 9 further includes a second presser plate 93, the second presser plate 93 being adjacent to the second clutch 7 via the above-described ring 107, the second presser plate 93 includes a plurality of leg portions 93L extending in a direction opposite to the second clutch 7, that is, the drive plate 95, and the plurality of leg portions 93L are further arranged in axial symmetry, and correspondingly, the drive plate 95 includes cam surfaces 99, each cam surface 99 including a bottom inclined in the circumferential direction as shown in fig. 5, the inclination can be relatively steep, and the combination of the leg portions 93L and the cam surfaces 99 constitutes the second cam mechanism 101.

Cam plate 81 has through holes 81H corresponding to leg portions 93L, and as shown in FIG. 5, leg portions 93L face cam surfaces 99 through holes 81H, and rotational movement R of drive plate 95 is caused_DAnd a rotational difference is generated between the cam plate 81, the leg portion 93L follows the cam plate 81, and then, the leg portion 93L slides on the cam surface 99 to ride up its inclined bottom, so that the second presser plate 93 moves in the axial direction, engaging the second clutch 7 via the ring member 107.

Referring to fig. 3 in conjunction with fig. 2B, the drive 9 is provided with a drive disc 95, which drive disc 95 overlaps the cam disc 81. The drive disk 95 is a substantially circular disk having a shape in which a semicircular disk having the same diameter as the cam disk 81 and a semicircular disk having a larger diameter than the cam disk 81 are combined. For example, the large diameter side thereof may be provided with gear teeth, which can be used for coupling with an external motor. Alternatively, the drive plate 95 itself may constitute a rotor of the motor, or may be driven by any drive device other than the motor or constitute a part of the drive device. The drive disk 95 is coaxial with the housing 1 and is supported so as to be able to rotate relative thereto. For example, the ball bearing 111 can be used for the rotatable support.

The pressing member 97 for driving the first cam mechanism 91 can be coupled to the large diameter side. In the illustrated example, the pressing member 97 is a coil spring, and the drive plate 95 includes a groove 95S in a semi-cylindrical shape into which the coil spring is fitted. Both ends of the pressing member 97 are supported in contact with both ends of the groove 95S, and a bracket or the like may be used to prevent the pressing member 97 from falling off. Both ends of the pressing member 97 formed of a coil spring are also in contact with the clamps 81G, respectively, and thus the cam plate 81 is rotated together with the drive disc 95.

Referring mainly to fig. 6A, until the drive disk 95 rotates from the initial position (first position) to the predetermined position (second position), the elastic force of the coil spring exceeds the reaction force received from the cam plate 81, so the drive disk 95 rotates the cam plate 81 together, and the first cam mechanism 91 applies a pressing force corresponding to the rotation angle to the first clutch 5, thereby operating the first clutch 5. The first cam mechanism 91 generates a large pressing force by the cam ball rolling on the gentle inclined surface, and is advantageous in operating the first clutch 5 as a friction clutch.

Referring mainly to fig. 6B, when the clutch member 75 is moved in the axial direction, the leg 93L rides on the cam surface 99 and the second presser plate 93 moves in the axial direction, as described above, when the rotational difference occurs, the leg 93L rides on the cam surface 99.

If the drive plate 95 is rotated beyond the second position to the third position, the second clutch 7 is engaged. The pressing force of the second cam mechanism 101 is weaker than that of the first cam mechanism 91, but it is not necessary to overcome the reaction force, and therefore a small pressing force is sufficient. As shown in fig. 7, since the side surface of the leg portion 77 abuts against the side surface of the through hole 19 after engagement and maintains this state, a large pressing force for maintaining engagement is not required.

The side surfaces of the leg portions 77 and the side surfaces of the through holes 19 may be slightly inclined in the circumferential direction. Such a configuration serves to convert the rotation Rc of the cover 13 into the pressing force F₂Thus helping to maintain engagement.

During the rotation from the second position into the third position, in the first cam mechanism 91, the cam ball 83 hardly rolls, or is stationary. Since the cam ball 83 does not enter a position deeper than the cam surface, when the drive disk 95 is reversely rotated, it can be quickly returned to the original position.

The second position is substantially uniquely determined according to the balance of the elastic force and the reaction force of the coil spring. That is, by adjusting the spring constant of the coil spring, the second position can be arbitrarily determined, the pressing force of the first cam mechanism 91 can be arbitrarily determined, and the upper limit of the braking force of the first clutch 5 can be arbitrarily determined.

According to the present embodiment, both the first clutch for limiting the differential motion and the second clutch for inhibiting the differential motion are operated by only a single drive plate. Since the above operation is controlled only in accordance with the rotation angle of the drive plate, the operation of the first and second clutches can be easily controlled. When the second clutch is engaged, the first clutch restricts the differential motion in advance, so that there is no relative rotation between the clutch teeth, and therefore engagement is not hindered.

In the above description, the pressing member 97 is a coil spring, but may be another elastic member. Alternatively, or in addition to this, a latch mechanism or a ratchet mechanism that holds the engagement from the first position to the second position and releases the engagement at the second position may be used. Alternatively, the second cam mechanism may be configured to operate with a delay from the first cam mechanism only by the configuration of the cam surface without using the pressing member.

Several embodiments have been described, but modifications and variations of the embodiments can be made based on the disclosure.