JPH051720Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention is a device for limiting differential rotation between a differential case and left and right axle shafts to which rotation of the case is torque distributed. It is related to.

<Prior art> The general structure of this type of differential limiting device (limited slip differential) is that between the differential case and the differential gear (mainly side gear) incorporated inside the differential case, A multi-plate clutch is provided in which friction plates that rotate with the case and friction plates that rotate with the operating gear are arranged alternately, and the differential limiting function is exerted by the frictional force generated by these multi-plate clutches. It's getting old.

In recent years, it has become necessary to control the friction torque for limiting the differential depending on the driving condition of the vehicle. As a control means for this differential limiting function, a cone member that makes frictional contact with the differential case is slidably assembled on the outer periphery of either the left or right axle shaft, and the cone member and the operating force are applied to the cone member. There is a structure in which a spring is interposed between the sleeve member and the sleeve member that provides the same (for example, see Japanese Utility Model Application No. 60-51340).

Another method is to incorporate a multi-plate clutch as described above between the differential case and the differential gear (side gear), and of each friction plate constituting this multi-plate clutch, the differential There is a configuration in which the number of friction plates rotating together with the gear is controlled to be increased or decreased by the operation of a driver (see Japanese Utility Model Application No. 62-96149).

<Problems to be solved by the invention> Among the above means for controlling the differential limiting function, in the above-mentioned configuration, it is necessary to The relationship with the accompanying change in the differential limiting function is the characteristic shown by A in FIG. That is, in the case of characteristic A, when the sleeve member reaches a certain stroke, the differential limiting function increases rapidly at point a, causing a shock in the running of the vehicle.

Therefore, if the spring constant of the spring is set high to avoid this, the differential limiting function will increase with a slight stroke of the sleeve member, resulting in a differential lock state (see characteristic B in Figure 4). .
For these reasons, delicate control of the differential limiting function is difficult.

In addition, regarding the control means for the differential limiting function described later, since the friction force for differential limiting is determined by the number of friction plates that rotate together with the differential gear, the differential limiting function is can only perform stepwise control according to the number of friction plates, and even with this, it is difficult to control delicate differential limiting functions.

The present invention aims to solve these problems.

<Means for solving the problems> The present invention is configured as follows in order to solve the above problems.

That is, as shown in FIG. 1 corresponding to the embodiment, the rotation of the differential case 1 that receives torque transmission from the engine is directed onto the rotation axis of the case 1 through the differential gear 4 within the case 1. Torque is distributed to the placed left and right axle shafts 6, 7. A sleeve 10 is attached to the outer periphery of either one of the axle shafts 6, 7 outside the case 1 so as to be slidable in the direction along the axis of the sleeve 10 and not relatively rotatable.

Between the sleeve 10 and the outer surface of the differential case 1 facing the sleeve 10, a plurality of annular spaces having mutually different diameters are formed around the axes of the axle shafts 6 and 7. ing. In each annular space 11, a multi-plate clutch 12 is incorporated, which is constituted by a combination of a friction plate 12a that rotates together with the case 1 and a friction plate 12b that rotates together with the sleeve 10. Furthermore, an elastic body 15 whose elastic force is varied for each multi-disc clutch 12 is incorporated between each of these multi-disc clutches 12 and the sleeve 10.

<Operation> In the above configuration, the differential rotation generated between the differential case 1 and the left and right axle shafts 6 and 7 to which the rotation of the case 1 is distributed constitutes each of the multi-plate clutches 12. It is limited according to the frictional force generated between the friction plates 12a and 12b, respectively.

Therefore, in order to control the frictional force for limiting the differential, the sleeve 10 is slid to the left in FIG. 1. Along with this, the elastic body 15
As a result, the pressing force on each multi-plate clutch 12 increases, and the frictional force generated between the friction plates 12a, 12b constituting these multi-plate clutches 12 increases. This controls the differential limiting function,
Depending on the setting of the frictional force, a differential lock condition can also be obtained.

Now, the above-mentioned annular spaces 11 have different diameters, and the diameters of the multi-plate clutches 12 installed in these annular spaces 11 also differ. Further, the elastic force of the elastic body 15 acting on each multi-disc clutch 12 also differs for each multi-disc clutch 12. Therefore, as the sleeve 10 is slid, each of the multi-disc clutches 12
The frictional force exerted by changes smoothly and over a wide range. This makes it possible to control the differential differential limiting function in a delicate manner depending on the driving condition of the vehicle.

<Example> Next, embodiments of the present invention will be described with reference to the drawings.

First, in Fig. 1, which shows a cross section of the main parts of a differential device equipped with a differential limiting device,
The differential case 1 is rotatably supported by left and right side bearings 2 with respect to a differential carrier (not shown) at two positions on the left and right sides thereof. Further, a ring gear 3 is fixed to the outer periphery of the differential case 1, and this ring gear 3 is always meshed with a drive pinion (not shown) that rotates in response to torque transmission from the engine. Therefore, the differential case 1 is rotated by the torque transmitted from the engine through the ring gear 3.

Inside the differential case 1 above,
A pinion 4a constituting the differential gear 4 and left and right side gears 4b meshing with the pinion 4a are incorporated. The left and right side gears 4b are arranged on the rotational axis of the differential case 1, and left and right axle shafts 6, 7 extending outside the case 1 are coupled to each side gear 4b so as to be capable of transmitting torque.

Further, the pinion 4a is positioned by a pinion shaft 5 supported at both ends by a differential case. Therefore, the rotation of the case 1 is caused by the above-mentioned pinion shaft 5 and pinion 4.
Torque is distributed to the left and right side gears 4b through the axle shafts 6 and 7, and rotational driving force is transmitted to the left and right drive wheels through the respective axle shafts 6 and 7.

Now, among the axle shafts 6 and 7 described above, the axle shaft 7 located on the right side in FIG. 1 has spline teeth 7a formed on the outer periphery of the shaft located outside the case 1. A sleeve 10 is assembled on the axis of the axle shaft 7, and the spline teeth 10a formed in the center hole of this sleeve extend in the direction along the axis of the spline teeth 7a of the axle shaft 7. are slidably engaged.

In the above differential case 1, the outer surface facing the sleeve 10 has a -
As is clear from FIG. 2, which shows a line cross section, a plurality of steps (three in the drawing) are formed around the axis of rotation of the case 1, that is, the axes of the axle shafts 6 and 7, and each having a different diameter. has been done. On the other hand, on the side of the sleeve 10 facing the case 1, a step having a shape corresponding to that of the case 1 is formed. 2) annular spaces 11 are constructed.

As is clear from FIG. 3, which is a partially enlarged view of FIG. 1, a multi-plate clutch 12 is incorporated inside each annular space 11. These multi-plate clutches 12 have an inner friction plate 12 that engages with the case 1 and rotates together with the case 1.
a and the sleeve 10 side, and this sleeve 1
0 and outer friction plates 12b that rotate together with the outer friction plates 12b are arranged alternately. Further, these friction plates 12a and 12b are movable in the axial direction with respect to the case 1 and the sleeve 10, respectively.

The friction plates 12a and 12b in each of the multi-plate clutches 12 contact each other and exert a frictional force, thereby creating a function of preventing relative rotation between the case 1 and the sleeve 10. , which limits the differential movement between the differential case 1 and the axle shafts 6, 7.

Furthermore, since each of the above multi-plate clutches 12 is incorporated into an annular space 11 having a different diameter,
Also in this multi-plate clutch 12, the diameters of the respective friction plates 12a and 12b that constitute the multi-plate clutch 12 are different.

On the other hand, cylinders 13 communicating with each annular space are formed at multiple locations (four locations in the drawing) in the circumferential direction of the sleeve 10 (a first
(See Figure and Figure 2). In each cylinder 13 communicating with each annular space 11, a piston 14 and an elastic body 15 using a coil spring are incorporated, as is clear from FIGS. 1 and 3. In other words, these elastic bodies 15 are connected to the multi-plate clutch 12 of each annular space 11 through the piston 14.
and the sleeve 10. Moreover, the elastic force (spring constant) of each elastic body 15 is different for each multi-disc clutch 12, and the spring constant of the elastic body 15 acting on the multi-disc clutch 12 with a small diameter is the largest and As the diameter of the plate clutch 12 increases, an elastic body 15 with a smaller spring constant is used.

The sleeve 10 is configured so that a predetermined driving device applies an operating force based on an operation based on the driver's will or a signal from an automatic control device that detects the running state of the vehicle.

In the differential limiting device configured as above,
When the sleeve 10 is slid to the left in FIG. 1, the friction force generated between the friction plates 12a and 12b of each multi-plate clutch 12 increases in accordance with the stroke. The differential movement of the differential device is limited.

As described above, the multi-plate clutch 12 has different diameters, and the elastic body 15 has different diameters.
is set to a larger spring constant as it acts on a multi-plate clutch 12 with a smaller diameter. Therefore, when the stroke amount of the sleeve 10 is small, the multi-disc clutch 12 with a small diameter exerts a frictional force through the elastic body 15 with a large spring constant, but since the frictional torque is small, the differential limiting function is also small. Become something. As the stroke amount of the sleeve 10 increases, the multi-disc clutch 12, which has a larger diameter, also generates a frictional force, and the frictional force for limiting the differential gradually increases.

Due to the above functions, the relationship between the sliding stroke of the sleeve 10 and the differential limiting function has a characteristic as shown by the solid line in FIG. You can see that it changes.

Note that the characteristics shown in FIG. 4 are for each body plate clutch 12.
It can be freely adjusted by setting the diameter of the elastic body 15 or the spring constant of the elastic body 15, and can be controlled steplessly from a normal differential device state that does not exhibit any differential limiting function to a differential lock state. It is also possible.

<Effects of the invention> The present invention has a plurality of sleeves with mutually different diameters between a sleeve that is slidably assembled to the outer periphery of one of the axle shafts and the outer surface of the differential case. constitutes an annular space,
Each of these annular spaces incorporates a multi-plate clutch that exerts frictional force to limit differential movement.
Moreover, by changing the elasticity of the elastic body interposed between each multi-disc clutch and the sleeve for each multi-disc clutch, sliding the sleeve can reduce the frictional force used to limit the differential. Depending on the final value of the friction force, it is possible to obtain a differential lock state, and the driver's will can vary the friction force slightly and over a wide range. The differential limiting function can be controlled.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and Fig. 1 is a cross-sectional view showing the main parts of a vehicle differential device equipped with a differential limiting device, and Fig. 2 shows only the differential case shown in Fig. 1. 3 is an enlarged cross-sectional view of the main parts of FIG. 1, and FIG. 4 shows the relationship between the operating stroke of the differential limiting device and the differential limiting function of a conventional differential limiting device. FIG. 1... differential case, 4... differential gear, 6, 7... axle shaft, 10... sleeve, 11... annular space, 12... multi-plate clutch, 12a, 12b... friction plate, 15...
Elastic body.

Claims (1)

[Claim for Utility Model Registration] Rotation of the differential case that receives torque transmission from the engine is distributed to the left and right axle shafts arranged on the rotation axis of the case through the differential gear inside the case. In the configuration, a sleeve is assembled outside the differential case so as to be slidable in a direction along the axis of either one of the axle shafts, and to be non-rotatable relative to the outer periphery of either one of the axle shafts. , a plurality of annular spaces centered on the axis of the axle shaft and configured to have mutually different diameters between the sleeve and the outer surface of the differential case opposing the sleeve, and each of these annular spaces a multi-plate clutch consisting of a respective combination of a friction plate which is incorporated in the case and rotates together with the case, and a friction plate which rotates together with the sleeve; A differential limiting device that includes an elastic body with varying elastic force for each clutch.