JPH09144846A - Differential limiting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the durability by reliably suppressing the production of drag torque of a pilot clutch throughout a range from a low speed to a high speed and rapidly release a differential limiting state. SOLUTION: A differential limiting device is formed in such a manner that an input from a differential case 1 is distributed to left and right output shafts 5 and 7 through a differential gear device, and a main clutch 14 is engaged by a thrust force produced by a pilot clutch 11 to fasten differential rotation members against each other and differentiation between the left and right output shafts 5 and 7 is limited. A weight 15 arranged between differential rotation members 4 and 6 having cam cone surfaces 4C and 6C positioned facing each other suppresses a thrust force by a radially externally energized spring 16 and a differential rotation centrifugal force.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a differential limiting device for limiting a differential between left and right output shafts by engaging a main clutch by a thrust force generated by a pilot clutch engaging between differential rotating members. Is.

[0002]

2. Description of the Related Art Conventionally, as a differential limiting device for limiting a differential between left and right output shafts by engaging a main clutch by a thrust force generated by a pilot clutch for engaging differential rotating members, For example, there is one described in Japanese Patent Laid-Open No. 5-221246 as shown in FIG. In this conventional example, a driving force from an engine (not shown) is transmitted to a ring gear that meshes with a drive pinion and a bevel tooth, and a diff case 31 that integrally fixes the ring gear.
To rotate. A main clutch 44 and a pilot clutch 41 are axially arranged in the differential case 31 with a planetary gear constituting a differential gear unit interposed therebetween. These clutches serve to limit the differential of the planetary gears.
The driving force input from the differential case 31 is transmitted to an internal gear 32 of a planetary gear that constitutes a differential device as a part of the differential case 31, and further via a pinion gear 33, a carrier 36 and a sun gear 34. Distribution will be transmitted to. The pinion gear 3
A plurality of pinions 3 are rotatably supported on the circumference of the carrier 36 by pinion shafts.
The internal gear 32 that meshes externally and the sun gear 34 that meshes internally are meshed with each other. The differential case 31 having the internal gear 32 further extends to the outside of the pilot clutch 41 as an outer and is configured to rotate integrally with the rotor 38 of the pilot clutch 41. The rotor 38 is externally fitted to the right output shaft 37 that forms the inner circumference of the carrier 36, and a right wheel drive shaft (not shown) is spline-fitted in the shaft portion of the right output shaft 37. The sun gear 34 constitutes the left output shaft 35,
A left wheel drive shaft (not shown) is similarly spline-fitted into the shaft portion of the left output shaft 35. The driving force from the differential case 31 transmitted to the pinion gear 33 is the pinion gear 3 depending on the driving resistance or the rotational speed difference between the left and right wheels.
3 is rotated about the axis of rotation and distributed and transmitted to the carrier 36 of the right wheel system and the sun gear 34 of the left wheel system.

When it is necessary to limit the differential action between the left and right wheels when a bad road such as a muddy road is encountered during traveling in such a differential drive state, the pilot clutch 4
The armature 45 made of a permanent magnet is excited and attracted by the electromagnet 39 arranged outside the rotor 38 of No. 1 so that the permanent magnet 45 is generated by the current flowing through the electromagnet 39.
The exciting force of the electromagnet is selected in accordance with the relationship with, and a predetermined differential limiting force is obtained. By moving the armature 45 to the right in the axial direction by suction, the pilot clutch 41 arranged between the armature 45 and the rotor 38 is engaged, and the outer and the cam ring 42 of the ball cam device which are in the differential rotation state are separated. When trying to rotate together,
The carrier 36, which also functions as a pressure ring, is pressed axially leftward by the thrust force generated through the ball 43 between the carrier 36 and the carrier 36 that constitutes the ball cam device. Thus, the pinion gear 33
The entire carrier 36 pivotally supported moves to the left, and the main clutch 44 arranged between the planetary gear and the differential case 31 is engaged. As a result, there is no relative rotation difference between the carrier 36 and the sun gear 34, and the differential between the left and right wheels is in a restricted state, so that the rotation of each pinion gear 33 is restricted, and the internal gear 32,
The pinion gear 33, the carrier 36, and the sun gear 34 also rotate with their relative rotations limited, and either one of the drive systems has a differential action due to the difference in the friction coefficient between the road surface and the tire between the front and rear wheels. It eliminates the fate of the differential gear of and enables escape from a rough road. In this example, since the armature 45 made of a permanent magnet is used, when a reverse current flows through the electromagnet 39, the permanent magnet 45
And the pilot clutch 41 becomes neutral and becomes a differential free state. When the supply amount of the reverse current is gradually decreased, the intermediate differential limited state is brought about by the engagement force of the pilot clutch 41 by the permanent magnet 45.
Next, when a positive current flows through the electromagnet 39, the permanent magnet 45
And the electromagnet 39 are attracted to each other, and the fastening force of the pilot clutch 41 increases. In this way, it is possible to obtain a more complete engagement state of the pilot clutch due to the limited exciting force of the electromagnet.

[0004]

However, in the limited slip differential device having such a pilot clutch,
Even if the electromagnet 39 is demagnetized in order to stop the differential limiting action, for example, the pilot clutch 41 is disengaged, particularly when high speed rotation is input to the differential case 31 side, the multi-plate clutch configuring the pilot clutch 41 is formed. A drag torque is generated therebetween to rotate the cam ring 42, and the thrust force generated via the ball 43 between the cam ring 42 and the carrier 36 constituting the ball cam device pushes the carrier 36 axially leftward. As a result, the main clutch 44 is always pressed against the main clutch 44, resulting in deterioration of its durability. Moreover, for this reason, it is impossible to quickly cancel the limited differential state. Further, in such a differential limiting device, when the viscosity of the lubricating oil present inside the differential case is high at the time of starting in a cold region, etc., even if the electromagnet is demagnetized in the same manner as described above, drag torque is generated on the pilot clutch side. However, the main clutch is pressed to cause a problem such as a so-called tight corner braking phenomenon that deteriorates low-speed turning performance.

Therefore, the present invention solves the problems in the above-described conventional differential limiting device provided with a pilot clutch, and reliably suppresses the generation of drag torque in the pilot clutch from low speed to high speed, thus ensuring durability. (EN) Provided is a differential limiting device capable of improving the performance and promptly canceling the differential limited state.

[0006]

SUMMARY OF THE INVENTION Therefore, according to the present invention, an input from a differential case is distributed to and transmitted to the left and right output shafts via a differential gear device, and is generated by a pilot clutch that engages between differential rotating members. In the differential limiting device that engages the main clutch with the thrust force to limit the differential between the left and right output shafts, the weights arranged between the differential rotating members facing each other on the cam cone surface are radially outward. The thrust force is restrained by a biased spring and a differential rotary centrifugal force, which is a means for solving the problem. In the present invention, the cam conical surface is formed on a facing surface between a sun gear connected to one output shaft and a pinion carrier connected to the other output shaft in a differential gear device including a planetary gear. It is characterized by the fact that it is a means for solving the problem.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A first embodiment of the present invention will be described below with reference to FIG.
A description will be given based on FIG. FIG. 1 is a cross-sectional view showing an upper half of a first embodiment of a differential limiting device of the present invention, in which a driving force from an engine (not shown) is transmitted to an input shaft 1A and fixed to the input shaft 1A. 1 is transmitted. In the differential case 1, a main clutch 14 and a pilot clutch 11 are arranged in the axial direction with a planetary gear that constitutes a differential gear device interposed therebetween. The driving force input from the differential case 1 is transmitted to the internal gear 2 on the inner periphery of the differential case 1, and further through a pinion gear 3 that constitutes a planetary gear and meshes with the internal gear 2 internally. It is distributed and transmitted to the sun gear 4 which is in external mesh with the outer pinion gear 3 on the inner peripheral side of the carrier 6 and the pinion gear 3. The planetary gear is a double pinion type, which can smoothly give a left and right rotation difference. The pinion gear 3 has a pinion shaft 3A.
A plurality of pinion gears 3 are rotatably supported on the circumference of the pinion carrier 6, and the internal gear 2 that meshes with the external gear and the sun gear 4 that meshes with the internal gear mesh with the inside and the outside of the pinion gears 3, respectively. The internal gear 2
The differential case 1 having the
The rotor 8 of the pilot clutch 11
Is configured to rotate integrally with. The rotor 8
Is externally fitted to the right output shaft 7 which is spline-fitted to the inner circumference of the pinion carrier 6. The sun gear 4 constitutes a left output shaft 5, and a left wheel drive shaft (not shown) is spline-fitted in the shaft portion of the left output shaft 5. The driving force from the differential case 1 transmitted to the pinion gear 3 is revolved around the pinion gear 3 depending on the driving resistance or the rotational speed difference between the left and right wheels, and the pinion carrier 6 of the right wheel system is rotated.
And transmitted to the sun gear 4 of the left wheel system in a distributed manner.

On the other hand, in the present embodiment, the armature 10 that is attracted by the excitation of the electromagnet 9 and that engages the pilot clutch 11 is provided between the pinion carrier 6 and the rotor 8 that form the planetary gear. The operation mode of the clutch does not necessarily have to be the electromagnet type. The pilot clutch 11 rotates together with the rotor 8 and slides in the axial direction in a multi-disc clutch group, and also rotates together with the cam ring 12 constituting the cam ball device arranged on the inner peripheral side of the pilot clutch 11 and slides together. A cam ring 12 that is composed of a possible multi-disc clutch group, and tries to rotate with the rotation of the differential case 1 when the clutch is engaged.
The thrust force is generated by the relative rotation between the pinion carrier 6 and the cam ball 13 and the pinion carrier 6 is moved in the axial direction (left direction in the drawing), the main clutch 14 is engaged, and the differential case 1 side. The outer plate 14A that rotates together with the sun gear 4 and the inner plate 14B that rotates together are connected to eliminate relative rotation between the differential case 1 and the left and right output shafts 5, 7.
A so-called differential limiting action is performed.

In the present invention, as clearly shown in FIG. 2, which is an enlarged view of the portion A in FIG. 1, it is connected to one output shaft (left output shaft 5) in the differential gear device composed of a planetary gear. Cam conical surfaces 4C, 6C are formed on the opposing surfaces between the sun gear 4 and the pinion carrier 6 connected to the other output shaft (right output shaft 7).
A plurality of centrifugal balls 15 as weights are circumferentially held between differential rotation members (sun gear 4 and pinion carrier 6) facing each other at C by springs 16 urged radially outward. . Reference numeral 17 indicates the centrifugal ball 15 and a holding ring that holds these in a predetermined position. In addition, the cam conical surface 4C of the sun gear 4
By appropriately setting the inclination angle θ of the cam conical surface 6C of the pinion carrier 6, it is possible to generate an anti-thrust force for suppressing drag torque in a wide range.

The operation of the present embodiment will be described with the above configuration. When traveling in a normal differential drive state, a rough road such as a muddy road is encountered and the differential operation between the left and right wheels is limited. When the need arises, the armature 10 is attracted by the excitation of the electromagnet 9 and the pilot clutch 11 is engaged,
When the differential case 1 and the cam ring 12 try to rotate together, the pinion carrier 6 is pressed axially leftward by the thrust force generated through the ball 13 between the differential case 1 and the cam ring 12 and the pinion carrier 6 that constitutes the ball cam device. As a result, the pinion carrier 6 supporting the pinion gear 3 is supported.
The whole moves to the left in the drawing, and the main clutch 14 arranged between the planetary gear and the differential case 1 (the side surface of the input shaft 1A) is engaged, and the outer plate 14A and the sun gear 4 that rotate together with the differential case 1 side. And the inner plate 14B that rotates together are connected to eliminate relative rotation between the differential case 1 and the left and right output shafts 5 and 7, so-called differential limiting action is performed.

Next, when the electromagnet 9 is demagnetized to release the differential limiting state, and at a relatively low speed where there is not much difference in the differential rotation speed in the differential device including the planetary gears,
A drag torque is generated between the multi-plate clutches constituting the pilot clutch 11 to rotate the cam ring 12, and the pinion carrier 6 is driven by the thrust force generated via the balls 13 between the pin ring carrier 6 and the pinion carrier 6 constituting the ball cam device. Even if the centrifugal ball 15 is pressed to the left in the axial direction, the centrifugal ball 15 is urged outward in the radial direction by the spring 1.
Cam conical surface 4 formed on the opposing surfaces of the sun gear 4 and the pinion carrier 6, which are differential rotating members opposed to each other.
C and 6C are expanded in the axial direction, the pinion carrier 6 is pushed back to the axial right side against the thrust force, and the unnecessary engagement of the main clutch 14 due to the drag torque of the pilot clutch 11 is effectively suppressed. It is possible to improve the durability performance and quickly release the differential limiting state.

Further, when high speed rotation is input to the input shaft 1A, that is, the differential case 1 side in the case where the electromagnet 9 is demagnetized to release the differential limiting state, a larger amount is generated between the multiple disc clutches forming the pilot clutch 11. As the drag torque is generated, the cam ring 12 is rotated in the same manner as described above, and the large thrust force generated via the ball 13 between the pinion carrier 6 and the pinion carrier 6 which constitutes the ball cam device makes the pinion carrier 6 strong in the axial left direction. However, in addition to the biasing force of the spring 16 biased outward in the radial direction, the centrifugal ball 15 opposes by a large differential centrifugal force between the differential rotating member (the sun gear 4 and the pinion carrier 6). Sun gear 4 which is a differential rotation member
The cam conical surfaces 4C, 6C formed on the surfaces facing each other and the pinion carrier 6 are strongly pushed in the axial direction to push the pinion carrier 6 back to the axial right side against the thrust force. It is possible to more effectively suppress the unnecessary engagement of the main clutch 14 due to the torque, and it is also possible to cancel the differential limited state more quickly.

Next, a second embodiment of the differential limiting device of the present invention will be described with reference to FIG. The configuration of this embodiment is also
The weight arranged between the differential rotation member sun gear 4 and the pinion carrier 6 facing each other at the cam conical surfaces 4C and 6C is dragged in the pilot clutch 11 by the spring and the differential rotation centrifugal force that are urged radially outward. Although it is basically the same as that of the first embodiment in that it is configured to suppress the thrust force generated by the torque, in the present embodiment, a large number of centrifugal balls 15 are used as weights. In place of a plurality of (three in the illustrated embodiment) arcuate bodies 18A having a trapezoidal cross section,
18B and 18C are adopted, and a ring-shaped coil spring 19 is installed in a groove 20 having a semi-arcuate cross section carved on the inner peripheral side of these arc-shaped bodies. As a result, when the electromagnet 9 is demagnetized to release the differential limiting state, and at a relatively low speed where there is not much difference in the differential rotation speed in the differential device, the coil spring 19 formed in a ring shape tends to expand. Arc-shaped bodies 18A, 18B, and 18C having trapezoidal cross-sections that are weights due to the spring force urged to
Of the pilot clutch 41 by moving the
It effectively suppresses the disengagement of the main clutch 14 due to the drag torque, and improves the durability performance. further,
Even if high speed rotation is input to the differential case 1 side and a large drag torque is generated between the multiple disc clutches constituting the pilot clutch 11 to strongly push the pinion carrier 6 axially leftward by a large thrust force,
Circular trapezoidal bodies 18A, 18B and 1 which are weights
In addition to the urging force of the spring 19 urged outward in the radial direction, 8C is a large differential rotational centrifugal force between the sun gear 4 and the pinion carrier 6, whereby the inclined surfaces on both sides of the trapezoidal cross section of each of the arcuate bodies are described above. The cam conical surfaces 4C and 6C are strongly expanded in the axial direction, the pinion carrier 6 is pushed back to the right in the axial direction against the thrust force, and the main clutch 14 is disengaged due to the drag torque of the pilot clutch 11. It can be suppressed more effectively.

Next, a third embodiment of the differential limiting device of the present invention will be described with reference to FIG. The configuration of this embodiment is also
As a weight, a plurality of trapezoidal cross-sections (three in the illustrated embodiment) arranged on the circumference instead of a large number of centrifugal balls 15
This is basically the same as that of the second embodiment in that the arc-shaped bodies 18A, 18B and 18C are adopted, but in the present embodiment, a plurality of circles having a trapezoidal cross section as weights are used. As a spring for urging the arcuate bodies 18A, 18B, and 18C outward in the radial direction, each arcuate body 1 is used instead of the ring-shaped coil spring 19 of the second embodiment.
A compression spring 21 is provided between 8A, 18B and 18C so as to connect them. The compression spring 21 urges the arcuate bodies 18A, 18B, and 18C in a direction to separate them from each other in the circumferential direction, thereby obtaining a biasing force outward in the radial direction. As a result, when the differential limited state is released, engagement of the main clutch due to drag torque in the pilot clutch is effectively suppressed from relatively low speed to high speed differential rotation, and durability performance is improved,
In addition, it is possible to quickly release the differential limiting action.

Although the embodiments of the present invention have been described above, a differential gear device having an appropriate structure can be adopted within the scope of the present invention. As for the manner of engaging and disengaging the pilot clutch, not only the electromagnet method but also a fluid pressure method, an engagement reaction force method, or the like can be adopted. Further, the shape of the armature, the cam ring or the pinion carrier and their related configurations, the shape of the cam conical surface, the shape of the weight, the spring and the retaining ring, the number and their related configurations, and the member on which the cam conical surface is formed. Also in regard to, an appropriate differential rotation member can be adopted.

[0016]

As described above in detail, according to the present invention, a relatively low differential rotation speed in which the differential rotation speed in the differential device including the planetary gears is not so different when the differential limited state is released. At times, even if the main clutch tries to be engaged by the thrust force due to the drag torque between the multi-plate clutches forming the pilot clutch, the weight member opposes by the spring biased outward in the radial direction. The cam conical surface formed on the surface is expanded in the axial direction to effectively suppress the engagement of the main clutch against the thrust force to improve the durability performance and quickly release the differential limiting state. Is possible. Also, even if the viscosity of the lubricating oil inside the differential case is high, such as when starting in cold regions, drag torque will not be generated on the pilot clutch side when the electromagnet is demagnetized, so the main clutch The problem such as the tight corner braking phenomenon that is pressed against the wheel and deteriorates the low-speed turning performance is solved. Furthermore, when the differential limiting state is released and during high-speed differential rotation when high-speed rotation is input to the input shaft side, the main clutch is driven by the thrust force due to the larger drag torque between the multiple disc clutches that make up the pilot clutch. Even if it is attempted to be fastened, the weight member is formed on the facing surface between the differential rotating members that are opposed to each other by the large differential rotating centrifugal force between the differential rotating members in addition to the biasing force of the spring biased outward in the radial direction. Push the cam conical surface that has been splayed strongly in the axial direction,
It is possible to reliably suppress the engagement of the main clutch against the thrust force to improve the durability performance and release the differential limited state more quickly.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an upper half of a first embodiment of a differential limiting device of the present invention.

FIG. 2 is an enlarged view of a portion A in FIG.

FIG. 3 is a diagram corresponding to a portion A showing a second embodiment of the differential limiting device of the invention.

FIG. 4 is a view corresponding to a portion A showing a third embodiment of the differential limiting device of the invention.

FIG. 5 is an overall view of a conventional differential limiting device.

[Explanation of symbols]

 1 differential case 2 internal gear 3 pinion gear 4 sun gear 4C cam conical surface 5 left output shaft 6 pinion carrier 6C cam conical surface 7 right output shaft 8 rotor 9 electromagnet 10 armature 11 pilot clutch 12 cam ring 13 ball 14 maincucci 15 centrifugal ball (heavy weight) ) 16 spring 17 retaining ring 18 arcuate member (weight) 19 coil spring 20 groove 21 compression spring

Claims (2)

[Claims] 1. An input from a differential case is distributed and transmitted to left and right output shafts via a differential gear device, and a main clutch is engaged by a thrust force generated by a pilot clutch that engages between differential rotating members. In a differential limiting device that limits the differential between the left and right output shafts, a weight disposed between differential rotating members facing each other on a cam cone surface is biased radially outward by a spring and differential rotation. A differential limiting device configured to suppress the thrust force by a centrifugal force. 2. The cam conical surface is formed on an opposing surface between a sun gear connected to one output shaft and a pinion carrier connected to the other output shaft in a differential gear device including a planetary gear. Claim 1 characterized in that
The differential limiting device according to 1.