JP3246079B2 - Rotational differential fitting - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotational difference sensitive joint for transmitting power according to a rotational difference between two shafts.

[0002]

2. Description of the Related Art Conventionally, a rotational difference sensitive joint is disclosed in
As described in JP-A--24329, a piston is provided which moves in response to a rotational difference between two shafts via a cam surface, and a working fluid flows from the accumulator chamber into the piston chamber via a check valve during a suction stroke of the piston. During the discharge stroke, while the working fluid is returned from the piston chamber to the accumulator chamber via the variable orifice, the flow rate of the working fluid is restricted by the variable orifice, and the rotation difference between the two shafts is controlled via the piston and the cam surface. There is a known power transmission.

[0003] In this kind of rotation difference sensitive joint, the relationship between the rotation difference and the transmission torque can be arbitrarily set by controlling the opening degree of the variable orifice.

[0004]

However, the relationship between the rotation difference and the transmission torque becomes a quadratic curve as shown in FIG. 3, for example, and the following problem occurs.

That is, when the opening degree of the variable orifice is increased, the transmission torque is small as a whole and the amount of change in torque with respect to the change in rotation is small. When the degree is reduced, a change in torque with respect to a change in rotation difference becomes agile, and a slight difference in opening degree of the orifice causes a large change in transmission torque. For this reason, it is necessary to control the opening degree of the orifice with high precision, and it is unavoidable that the orifice opening becomes disadvantageous in terms of cost, and it has not been possible to achieve the required precision even with this.

In order to increase the torque transmission capacity, a large number of sets of cam surfaces and pistons are usually provided at equal intervals in the circumferential direction. However, each set is manufactured so as to have the same torque transmission characteristics. However, it is difficult to secure durability because the stress is concentrated on a specific group due to a manufacturing error.

An object of the present invention is to depart from the conventional idea of controlling only by the opening degree of a variable orifice, and to make it possible to change the torque transmission characteristic by another means which does not cause the above-mentioned problem. And

[0008]

SUMMARY OF THE INVENTION To this end, the present invention comprises a piston which strokes in response to a rotational difference between two shafts via a cam surface, and which moves from the accumulator chamber through a check valve during a suction stroke of the piston. While the working fluid flows into the piston chamber and the working fluid is returned from the piston chamber to the accumulator chamber through the variable orifice during the discharge stroke, the flow rate of the working fluid by the variable orifice is restricted by the two shafts via the piston and the cam surface. In a rotation-difference-sensitive joint adapted to transmit power according to the rotation difference between the accumulator chamber and the accumulator chamber, the pressure adjustment means can control the internal pressure of the accumulator chamber by applying pressure. A power transmission characteristic according to a rotation difference between the two shafts can be changed by internal pressure control. A.

[0009]

When there is a rotation difference between the two shafts, the piston is stroked by the cam. During the suction stroke of the piston,
The working fluid flows from the accumulator chamber into the piston chamber via the check valve, and is returned from the piston chamber to the accumulator chamber via the variable orifice during the discharge stroke. The piston and the cam surface transmit power between the two shafts according to the rotation difference by restricting the flow rate of the working fluid by the variable orifice.

In this power transmission, the torque transmission characteristics can be changed by controlling the opening degree of the variable orifice as well as by controlling the internal pressure of the accumulator chamber by the pressure regulating means. be able to. According to the control of the torque transmission characteristic by the latter pressure adjusting means, the torque change characteristic with respect to the rotation difference change becomes insensitive, and there is no need to use the characteristic in which the torque change with respect to the rotation difference change is agile. Transmission torque control is possible. For this reason, it is not necessary to control the variable orifice opening with high precision, which is very advantageous in terms of cost. Still, the transmission torque can be controlled with the required stable precision.

For the same reason, it is customary to provide a large number of sets of cam surfaces and pistons at equal intervals in the circumferential direction in order to obtain a torque transmission capacity. Can be easily performed, and the stress is not concentrated on a specific set and the durability is not reduced.

[0012]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows an embodiment of the rotational difference sensitive joint of the present invention configured as a differential limiting device of a differential gear device, which is basically configured in the same manner as the differential limiting type differential gear device described in the above-mentioned document. I do.

Reference numeral 1 denotes a differential gear housing mounted on a vehicle body, and 2 denotes a differential gear case rotatably supported in the differential gear housing 1.
Is driven by a final drive gear set which is engaged with the final drive ring gear 3 and the final drive pinion 4 attached thereto.

In the differential gear case 2,
A pinion mate gear 5 is rotatably supported, and side gears 6 and 7 meshing from both sides are rotatably housed therein. One side gear 6 is spline-coupled to a side flange 9 for a left driving wheel via an adapter 8, and the other side gear 7 is directly spline-coupled to a side flange 10 for a right driving wheel.

A cylinder member 11 is provided by spline fitting with the side flange 10, and a piston 12 is provided on the cylinder member 11 so as to be slidable in the radial direction. Each piston 12 has an outer end far from the piston chamber 13 abutting against a circumferential cam surface 14 formed on the side gear 6, and each piston chamber 13 is connected to an accumulator chamber 16 via a check valve 15.
The check valve 15 is moved from the accumulator chamber 16 to the piston chamber 13.
It is arranged so that the working fluid can flow.

The piston chamber 13 and the accumulator chamber 1
Separately, a common variable orifice 17 is connected through the variable orifice 17, and the variable orifice is connected to a port member 18 inserted at the center of rotation of the cylinder member 11, a spool 19 slidably fitted to the port member 18, and the spool. And an actuator arm 20 for performing a stroke.

The accumulator chamber 16 includes the cylinder member 11
Defined by an accumulator piston 21 fitted to
This accumulator piston is urged toward the accumulator chamber 16 by a spring 22. The accumulator chamber 16 further includes a pipe 2 attached to an accumulator piston 21.
3, through the center hole 24 of the side flange 10,
The pipe 23 is slidably inserted into the center hole so that the reciprocating motion of the accumulator piston 21 is not hindered.
The side flange 10 is further provided with a radial hole 25 communicating with the center hole 24, and this hole is connected to the output port of a pressure regulating valve 29 as a pressure regulating means via a communication hole 26 of the differential gear housing 1 and a hose 28. I do. An input port of the pressure regulating valve 29 is driven by a power source 30 such as an engine to rotate and pump 32 which discharges hydraulic oil in a tank 31.
Connect to the output port of

The pressure regulating valve 29 is an electromagnetic valve having a solenoid 29a. The pressure regulating valve 29 applies a pressure which increases in proportion to the drive duty or current of the solenoid to the hose 28, the holes 26, 2 and
5, 24 and the pipe 23 are sequentially applied to the accumulator chamber 16.

The operation of the above embodiment will now be described. The rotation input from the final drive pinion 4 reaches the differential gear case 2 via the final drive ring gear 3 and rotates the differential gear case 2 around the rotation axis of the side flanges 9 and 10. As a result, the differential gear case 2 rotates the pinion mate gear 5 in the same direction, and transmits rotational power to both side gears 6 and 7. The side gear 6 is connected to a side flange 9 via an adapter member 8.
(Left driving wheel), and the side gear 7 directly drives the side flange 10 (right driving wheel). If the driving force is the same for the left and right driving wheels, the rotational speed of both side flanges 9 and 10 will be the same, and when the driving force is different for the left and right driving wheels, the rotational speed of both side flanges 9 and 10 will be different. And a rotation difference is generated between the two.

When there is this rotation difference, relative rotation between the side gear 6 and the cylinder member 11 is induced, and the cam surface 14
Causes the piston 12 to stroke. During the suction stroke of the piston 12, the hydraulic oil in the accumulator chamber 16 flows into the piston chamber 13 via the check valve 15, and the piston 1
During the second discharge stroke, the hydraulic oil in the piston chamber 13 is returned to the accumulator chamber 16 via the variable orifice 17 at a rate corresponding to the opening degree of the orifice. Therefore, the variable orifice 17 moves from the piston chamber 13 to the accumulator chamber 1.
This restricts the return of the hydraulic oil to the piston 6, and the flow rate restriction causes the piston 12 and the cam surface 14 to transmit power between the side flanges 9 and 10 according to the rotation difference between them. Thus, the relative rotation of the side flanges 9 and 10, that is, the differential of the differential gear device can be limited.

[0021] Incidentally, transmission torque characteristics for rotation difference △ N of the rotation difference sensitive coupling of eliciting such a differential limiting changes to as shown in the FIG. 2 example according to the internal pressure P _A of the accumulator chamber 16. Each characteristic a, b, c is kept opening diameter of the variable orifice 17 to 0.56φ, 6Kg / cm ² pressure P _A of the accumulator chamber 16, 200 Kg
/ Cm ² , 400 Kg / cm ² , the transmission torque characteristics when raised, and d, e, and f each maintain the opening degree diameter of the variable orifice 17 at 0.2φ and the pressure P _{A of the} accumulator chamber 16. Of 6Kg / cm ² , 200Kg /
cm ^2, and the transmission torque characteristics when raised with 400 Kg / cm ^2.

As is apparent from this, when a torque of about 20 to 40 kg · m is generated in a low rotational speed difference area of about 50 rpm or less (in a normal automobile, when a differential limitation is performed, the torque is generally in this range. 3), it was difficult to perform stable control as described above with the characteristics shown in FIG. 3, but according to the characteristics shown in FIG. 2, the opening diameter of the variable orifice 17 was 0.56.
Keep in φ, adjusts the pressure P _A of the accumulator chamber 16 valve 2
By performing the electronic control according to 9, the required torque can be stably generated. Therefore, under normal operating conditions, the accumulator chamber pressure is controlled by the pressure regulating valve 29 so that a highly accurate and stable differential limit can be obtained as required. Only at the time of escape from the state or at the time of an anti-skid request, the opening degree of the variable orifice 17 is reduced to generate a required transmission torque.

[0023]

As described above, according to the first aspect of the present invention, the internal pressure of the accumulator chamber can be controlled externally to change the transmission torque. It is not necessary to change the transmission torque using the torque change characteristic in which the torque changes quickly, and stable transmission torque control is possible.

For this reason, it is not necessary to control the variable orifice opening with high accuracy, which is very advantageous in terms of cost. Nevertheless, the transmission torque can be controlled with high accuracy.

For the same reason, although it is customary to provide a large number of sets of cam surfaces and pistons at equal intervals in the circumferential direction, it is easy to achieve the same transmission torque in each set. In addition, the stress is not concentrated on a specific group, and the durability is not reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view of a differential limited differential gear device showing an embodiment of a rotational difference sensitive joint according to the present invention.

FIG. 2 is a diagram showing a transmission torque characteristic with respect to a rotation difference of a rotation difference sensitive joint used as a differential limiting device in the same example.

FIG. 3 is a diagram illustrating a transmission torque characteristic with respect to a rotation difference of a conventional rotation difference sensitive joint that controls a transmission torque only through a variable orifice opening.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Differential gear housing 2 Differential gear case 3 Final drive ring gear 4 Final drive pinion 5 Pinion mate gear 6 Side gear 7 Side gear 8 Adapter member 9 Side flange 10 Side flange 11 Cylinder member 12 Piston 13 Piston chamber 14 Cam surface 15 Check valve 16 Accumulator chamber 17 Variable orifice 29 Pressure regulating valve (pressure regulating means) 30 Engine 31 Tank 32 Pump

Continuation of front page (56) References JP-A-3-20122 (JP, A) JP-A-3-24329 (JP, A) JP-A-2-93124 (JP, A) JP-A-5-106649 (JP) JP-A-5-87159 (JP, A) JP-A-4-64726 (JP, A) JP-A-4-81328 (JP, A) JP-A-2-296015 (JP, A) 2-27028 (JP, U) Japanese Utility Model 1-73563 (JP, U) (58) Fields surveyed (Int. Cl. ⁷ , DB name) F16D 31/02

Claims (1)

(57) [Claims] 1. A piston which strokes in response to a rotation difference between two axes via a cam surface, wherein a working fluid flows into a piston chamber from an accumulator chamber via a check valve during a suction stroke of the piston and a discharge stroke during a discharge stroke. While the working fluid is returned from the piston chamber to the accumulator chamber via the variable orifice, the flow rate of the working fluid by the variable orifice is restricted by the piston and the cam surface through the piston and the cam surface.
In a rotation difference sensitive joint adapted to transmit power according to the rotation difference between shafts, a pressure adjusting means capable of controlling the internal pressure of the accumulator chamber by applying pressure is provided, and the accumulator chamber is controlled by the pressure adjusting means. A power transmission characteristic corresponding to the rotation difference between the two shafts can be changed by the internal pressure control.