JP2000104807A - Limited slip differential gear - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a limited slip differential gear(LSD) which can adjust the responsiveness of a differential restriction finely. SOLUTION: Plural coil splings 14 in which a spring pressure acts in the same direction as the component action direction of a cam component mechanism are arranged exchangably between a pair of pressure rings 2, 3 of LSD and a disc shape spring 15 in which the spring pressure acts in the opposite direction to the action direction of the coil spring 14 is arranged between the side wall surface of a differential case 1 and multiplates friction clutches 8, 9 and by adjusting the pressure difference between the coil spring 14 and disc shape spring 15, the responsiveness of the differential restriction can be changed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a limited slip differential gear, and more particularly to a limited slip differential gear capable of arbitrarily selecting a response, which is a characteristic from the beginning to the end of a differential restriction to locking.

[0002]

2. Description of the Related Art When a rotational driving force in a forward direction is transmitted from an engine side as a limited slip differential gear (hereinafter abbreviated as LSD), an advantage of differential limitation is started. Has been proposed by the present applicant (Japanese Patent Publication No. 5-17421).

As shown in FIGS. 4 and 5, this LSD has a differential case 1 which is rotated by a driving force from an engine, and a case in which the drive wheels are movable in the axial direction of axles 10 and 11. , A pair of pressure rings 2 and 3 housed opposite to each other, a pinion shaft (formed in a cross shape) 4 sandwiched between the pair of pressure rings 2 and 3, and a tip end of the shaft. A pinion gear 5 that is freely mounted, a pair of side gears 6 and 7 that are arranged to sandwich the pinion gear 5 from both sides, and that mesh with the pinion gear 5 to transmit driving force to the axle; And the side gears 6 and 7 are pressure-bonded by the outward movement of the pressure rings 2 and 3 in the axle direction. And a multi-plate friction clutch for limiting the differential between the two-plate friction clutch and the pressure ring. , 9 are crimped, the axial cross section of the pinion shaft 4 is substantially D
The pressure rings 2, 3 are formed symmetrically with notches 2 a, 3 a forming cam surfaces that engage with the shaft of the pinion shaft 4 (both notches are formed). (Formed into a substantially triangular shape together).

When the rotational driving force in the forward direction is transmitted to the LSD by the cam component mechanism, the pair of pressure rings 2 and 3 are pushed apart to start the advantage of the differential limitation, and the engine brake is applied during forward travel. When the rotational driving force is transmitted from the driving wheel side when is operated, the pair of pressure rings 2 and 3 are not pushed and spread, and the differential limitation is not effective.

[0005] A ring gear 12 is fixed to the case 1, and a pinion gear 13 to which the rotation of the engine is transmitted is meshed with the ring gear 12.

In such an LSD, the degree of the advantage of the differential limitation, for example, when the accelerator is depressed during forward running, the advantage of the differential limitation is suddenly started, or the advantage of the differential limitation is gradually started. Can change the inclination angle of the inclined cam surface of the cam component force mechanism.

[0007]

However, the LSD
Are expensive parts, and the notch parts that constitute the cam component force mechanism formed on each of the pair of pressure rings have four cutouts of the same shape in one pressure ring, and the cutout of the pressure ring on the mating side. It must be formed so as not to be displaced from the notch, which is a very laborious operation and also increases the processing cost.

By the way, in order to be able to change the degree of the effect of such differential limitation according to the driver's preference and the conditions of the road on which the vehicle runs, the inclination angle of the cam surface in the cam component force mechanism must be changed. It is only necessary to be able to prepare a plurality of different types of pressure rings, but as described above, pressure rings are expensive, and it is very difficult to prepare pressure rings with cam surfaces that match the conditions of the road on which they travel. It can be said that.

On the other hand, as shown in FIG. 6, the present applicant mounts a coil spring 14 between a pair of pressure rings 2 and 3 and mounts the multi-plate friction clutches 8 and 9 to the case 1 as shown in FIG. Has been proposed to pre-press against the side surface of.

[0010] This configuration is such that a disc spring is disposed between the case and the multi-plate friction clutch to apply and compress the multi-plate friction clutch, and the torque transmitted to one wheel becomes extremely small. However, if a certain amount of torque (initial torque) can be transmitted to the other wheel,
When the wear of the multi-plate friction clutch advances during the press-fitting, the amount of wear exceeds the pressurizing stroke of the disc spring disposed between the multi-plate friction clutch and the case for applying a pressurization. Since the effect of the crimping by the disc spring is weakened, the disc spring is abolished, and a coil spring having a displacement stroke sufficiently larger than the effective displacement amount of the disc spring is disposed between the pair of pressure rings, and the multi-plate friction is increased. Even if the clutch is worn, sufficient crimping can be ensured.

In the LSD in which such a pressurizing spring is disposed between the pressure rings, the pressurizing spring has an additional function in addition to the above-described function of sufficiently pressing and pressing the multi-plate friction clutch even when the wear of the multi-plate friction clutch advances. ,
The present inventor has found that the influence of the differential restriction is affected.

However, the advantage of the differential limitation can be adjusted only when the response is faster than the advantage determined by the pressure dividing mechanism using the cam surface. Sex could not be slowed down.

It is an object of the invention according to the present application to adjust the dominance of differential limiting not only with a quicker response than that determined by a pressure dividing mechanism using a cam surface but also with a slow response. It is an object of the present invention to provide a limited-slip differential gear that can be set easily and has a finer adjustment range of the dominant condition and can be easily performed.

[0014]

A first configuration of a limited slip differential gear for realizing the object of the invention according to the present application is a differential case that rotates by a driving force from an engine, and rotates integrally with the case. A pair of pressure rings housed opposite to each other in the case so as to be movable in the axle direction of the drive wheels, a pinion gear rotatably mounted on a pinion shaft sandwiched between the pair of pressure rings, It is arranged so as to sandwich the pinion gear from both sides,
A pair of side gears each meshing with the pinion gear and transmitting driving force to the axle of the drive wheel, and are provided between the side wall surface of the case and the side gear, and the pressure ring is moved outward in the axle direction. A multi-plate clutch that is crimped to limit the differential between the two side gears, a cam component force mechanism formed on the pressure ring and the pinion shaft, and moving the pair of pressure rings outward in the axle direction away from each other; The pair of pressure rings are removably mounted in a plurality of holes formed in the outer peripheral facing portions of the pair of pressure rings so as to face each other along the circumferential direction, and a spring force acts in the same direction as the component force direction of the cam component mechanism. And a coil spring disposed between the multi-plate clutch and a side wall surface of the case. A disc spring that presses in a direction opposite to the direction of action of the ring, and a responsiveness of the differential limitation can be changed by a differential pressure between the spring force of the disc spring and the spring force generated by adjusting the spring force of the coil spring. It is what it was.

The second configuration of the limited slip differential gear for realizing the object of the invention according to the present application is as follows.
A differential case that is rotated by a driving force from an engine, a pair of pressure rings that rotate integrally with the case and are accommodated in the case so as to be movable in the axle direction of the drive wheels and face each other; A pinion gear rotatably mounted on a pinion shaft held by a pressure ring, and a pinion gear disposed so as to sandwich the pinion gear from both sides; each meshes with the pinion gear to transmit driving force to the axle of the drive wheel. A pair of side gears, a multi-plate clutch provided between a side wall surface of the case and the side gears and pressed by moving the pressure ring outward in the axle direction to limit a differential between the two side gears; A ring and a pair of pressure rings formed on the pinion shaft; A cam component force mechanism for moving the axle direction outward away from each other, and removably mounted in a plurality of holes formed in the outer peripheral opposing portions of the pair of pressure rings along the circumferential direction, respectively. A first spring force acting in the same direction as the component force direction of the cam component force mechanism;
And a hole formed in a side wall surface of the case along a circumferential direction on an outer peripheral portion of the multi-plate clutch. The multi-plate clutch is moved in a direction opposite to a direction of action of the first coil spring. And a second coil spring that presses the spring force of the first coil spring and the spring force of the second coil spring generated by adjusting the spring force of the first and second coil springs. The response of the differential limitation can be changed by the differential pressure.

A third configuration of a limited slip differential gear for realizing the object of the invention according to the present application is as follows.
When the driving force in the forward direction from the engine is transmitted to the differential case, a differential limit is effective, and when the driving force is transmitted from the driving wheel side to the differential case, the differential force mechanism is differential. A cam surface of the pressure ring is formed so as not to be restricted.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) FIG. 1 shows a first embodiment of the present invention.

In this embodiment, the conventional LS shown in FIG.
D, a disc spring 15 is disposed between the multi-plate friction clutches 8 and 9 and the side surface of the case 1.

The driving force from the engine is transmitted to the pinion gear 13.
In the differential case 1 which is transmitted to the ring gear 12 through the shaft and rotates, the axles 10 of the left and right driving wheels are provided.
A pair of opposing pressure rings 2, which are spline-coupled to the case 1 along the axial direction of 11 and are movable.
3 and a pinion shaft (formed in a cross shape) sandwiched between the pair of pressure rings 2 and 3
And a pair of pinion gears 5 rotatably attached to the tip of the shaft, and a pair of pinion gears 5 arranged to sandwich the pinion gear 5 from both sides and meshing with the pinion gear 5 to transmit driving force to the axle. Side gear 6,
7, provided between the case 1 and each of the side gears 6 and 7, and pressure-bonded by the outward movement of the pressure rings 2 and 3 in the axle direction to limit the differential between the two side gears 6 and 7. Plate friction clutches 8 and 9, a plurality of coil springs 14 disposed circumferentially on the outer peripheral surfaces of the pair of pressure rings 2 and 3, and a multi-plate friction clutch 8.
Disc spring 15 disposed between the casing 9 and the side wall surface of the case 1
And are housed.

The plurality of coil springs 14 are respectively provided with axially outward spring forces in holes 2b, 3b formed in the opposing surfaces of the pressure rings 2, 3 along the axles 10, 11 in the axial direction. When the pair of pressure rings 2 and 3 are in a position where the advantage of the differential limitation has not started yet as shown in FIG. 1, the pressure rings 2 and 3 are respectively directed outward from the axle. The urging pressure is applied to the pair of pressure rings 2 and 3.

The multi-plate friction clutches 8 and 9 are respectively pressed outwardly in the axial direction, and the multi-plate friction clutches 8 and 9 are pressed against the side wall surface of the case 1 against the spring force of the disc spring 15. In order to press, the axial cross section of the pinion shaft 4 is formed in a substantially D-shape, and the pressure rings 2 and 3 have a notch formed with a cam surface which engages with the shaft of the pinion shaft 4. There is provided a cam component mechanism in which 2a and 3a are formed symmetrically (both notches are combined to form a substantially triangular shape).

When the rotational driving force in the forward direction is transmitted to the LSD by this cam component mechanism, the curved surface of the pinion shaft 4 is brought into contact with the inclined surface, which is the cam surface of the notch, so as to be axially outward. When the engine brake is operated during forward running, the rotational driving force is transmitted from the driving wheel side. In this case, the linear surface of the substantially D-shaped cross section of the pinion shaft 4 comes into contact with the linear surface of the notch, and no component force is generated outward in the axial direction. It cannot be spread, and the differential restriction does not work.

Here, the coil spring 14 is also the disc spring 1
5 also acts as a pressurizing spring for applying a pressurization to the multi-plate friction clutch, and a coil spring 14 disposed between the pair of pressure rings 2 and 3 causes the pair of pressure rings 2 , 3 are spread out to press the multi-plate friction clutches 8, 9 against the side wall surface of the case 1 to perform an operation for applying a differential limit (hereinafter, this spring is referred to as a positive pressure spring), and a disc spring 15 is provided. Conversely acts in a direction to release the differential restriction by separating the multi-plate friction clutches 8, 9 from the side wall surface of the case 1 by the force in the direction of the arrow Y (hereinafter, this spring is referred to as a negative pressure spring).

Actually, the balance between the positive pressure spring 14 and the negative pressure spring 15 makes it possible to adjust the relationship between the differential limiting effect, that is, the restraining force against the input of the differential case 1 shown in FIG.

Here, if the total pressure X1 of the positive pressure spring 14 is larger than the total pressure Y1 of the negative pressure spring 14, the difference pressure is applied in the positive pressure direction (arrow X direction), and the differential force is limited by the component force mechanism. In addition to the component force for the operation, as shown by the characteristic line a, even if the input torque of the case 1 is small, the differential limit can be locked (the binding force of the multi-plate friction clutch is maximum).
For example, when the vehicle enters the corner with the engine brake applied, the left and right drive wheels are made differential, and the accelerator is depressed near the exit of the corner.

At this time, since the driver has not yet completely exited the curve when the accelerator pedal is depressed, when the drive wheels are driven in a slightly differential state, the total pressure Y1 of the negative pressure spring 15 is reduced.
Is larger than the total pressure X1 of the positive pressure spring 14, the differential pressure is applied in the negative pressure direction (arrow Y direction), and the component force for the differential limiting operation by the component force mechanism is reduced. As shown by the line b, the lock is not achieved unless the input torque of the case 1 increases (the engine speed is increased by blowing the accelerator), so that a certain degree of differential limiting operation can be obtained during that time.

In this embodiment, the positive pressure spring 14 is formed by a coil spring, a plurality of coil springs having different spring constants are prepared, and a coil spring having the same spring constant is provided in all or some of the holes. Alternatively, by installing coil springs having different spring constants, it is possible to obtain the advantage of limiting the differential at an arbitrary point c in a region shown by oblique lines between the characteristic lines a and b in FIG.

(Second Embodiment) FIG. 2 shows a second embodiment.

In the above-described first embodiment, the negative pressure spring 15 is a disc spring, but in the present embodiment, the positive pressure spring 14
The same coil spring is used.

The negative pressure spring 15 formed by a coil spring is inserted into a hole 1 a formed in the side wall of the case 1. The other configuration is the same as that of the first embodiment, and the description thereof is omitted.

In the present embodiment, since both the positive pressure spring 14 and the negative pressure spring 15 are the same coil spring, their diameters and lengths are made uniform, a plurality of springs having different spring constants are prepared, and these are appropriately combined. This makes it possible to obtain the advantage of limiting the differential at an arbitrary point c in the area shown by the diagonal lines between the characteristic lines a and b in FIG. In this case, since the positive pressure spring 14 and the negative pressure spring 15 are replaceable, it is possible to more finely adjust the effect of the differential restriction as compared with the case of the first embodiment.

[0032]

According to the first to third aspects of the present invention, the responsiveness of the differential limiting can be finely adjusted and can be set arbitrarily.

Further, the responsiveness of the differential limitation can be easily reduced by preparing a plurality of springs having different spring constants or by thinning out and mounting the coil springs in all of the plurality of holes without mounting them. Can be adjusted.

[Brief description of the drawings]

FIG. 1 is a sectional view of a limited slip differential gear according to a first embodiment of the present invention.

FIG. 2 is a sectional view of a limited slip differential gear showing a second embodiment of the present invention.

FIG. 3 is a diagram showing characteristics of responsiveness of the first and second embodiments of the present invention.

FIG. 4 is a sectional view of a conventional limited slip differential gear.

FIG. 5 is a sectional view of the limited slip differential gear of FIG. 4 including a side gear;

FIG. 6 is a sectional view of another conventional limited slip differential gear.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Differential case 2, 3 Pressure ring 4 Pinion shaft 5 Pinion gear 6, 7 Side gear 8, 9 Multiple disc friction clutch 10, 11 Axle 12 Ring gear 13 Pinion gear 14 Coil spring (positive pressure spring) 15 Disc spring (negative pressure spring) )

Claims (3)

[Claims] 1. A differential case which is rotated by a driving force from an engine, and a pair of pressure rings which are integrally rotatable with the case and accommodated in the case so as to be movable in the axle direction of driving wheels. And, a pinion gear rotatably attached to a pinion shaft held between the pair of pressure rings, and disposed so as to sandwich the pinion gear from both sides,
A pair of side gears each meshing with the pinion gear and transmitting driving force to the axle of the drive wheel, and are provided between the side wall surface of the case and the side gear, and the pressure ring is moved outward in the axle direction. A multi-plate clutch that is crimped to limit the differential between the two side gears, a cam component force mechanism formed on the pressure ring and the pinion shaft, and moving the pair of pressure rings outward in the axle direction away from each other; The pair of pressure rings are removably mounted in a plurality of holes formed in the outer peripheral facing portions of the pair of pressure rings so as to face each other along the circumferential direction, and a spring force acts in the same direction as the component force direction of the cam component mechanism. And a coil spring disposed between the multi-plate clutch and a side wall surface of the case. A disc spring that presses in a direction opposite to the direction of action of the ring, and a responsiveness of the differential limitation can be changed by a differential pressure between the spring force of the disc spring and the spring force generated by adjusting the spring force of the coil spring. Limited slip differential gear characterized by the following. 2. A differential case which is rotated by a driving force from an engine, and a pair of pressure rings which are integrally rotated with the case and are accommodated in the case so as to be movable in the axle direction of the drive wheels. And, a pinion gear rotatably attached to a pinion shaft held between the pair of pressure rings, and disposed so as to sandwich the pinion gear from both sides,
A pair of side gears each meshing with the pinion gear and transmitting driving force to the axle of the drive wheel, provided between the side wall surface of the case and the side gear, and by moving the pressure ring outward in the axle direction. A multi-plate clutch that is crimped to limit the differential between the two side gears, a cam component mechanism formed on the pressure ring and the pinion shaft, and moving the pair of pressure rings outward in the axle direction away from each other; The pair of pressure rings are removably attached to a plurality of holes formed facing each other along the circumferential direction in the outer peripheral facing portions of the pair of pressure rings, and a spring force acts in the same direction as the component force direction of the cam component mechanism. A first coil spring to be mounted in a hole formed in a side wall surface of the case along an outer circumferential portion of the multi-plate clutch along a circumferential direction. Is, the multi-plate clutch said first
Press in the opposite direction to the direction of action of the coil spring
And a pressure difference between the spring force of the first coil spring and the spring force of the second coil spring generated by adjusting the spring force of the first and second coil springs. A limited slip differential gear characterized in that the responsiveness of the motion restriction can be changed. 3. When the driving force in the forward direction from the engine is transmitted to the differential case, a differential limit is applied, and the driving force is transmitted from the driving wheel side to the differential case. 3. The limited slip differential gear according to claim 1, wherein a cam surface of the pressure ring is formed so that differential restriction is not effective in such a case.