JP2022183928A - Mechanical limited slip differential of vehicle - Google Patents

Abstract

To provide a constitution in which a differential limit mechanism portion is not sealed, and metallic friction powder from outer/inner claw clutch plates is not discharged to the outside of a differential case even if a structure is of a release type in which oil is common in use with a transmission, in a mechanical limited slip differential (LSD).SOLUTION: In a mechanical LSD 1, a non-metallic friction material 10 is interposed between an outer claw clutch plate 7 or a pressure ring 6 and an inner claw clutch plate 8, stopper mechanisms 9a, 9b for limiting the displacement of the pressure ring with respect to the outer claw clutch plate are arranged, and when the thickness of the friction material is reduced by a prescribed width Δ, the outer claw clutch plate or the pressure ring and the inner claw clutch plate do not approximate each other.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD The present invention relates to a mechanical limited slip differential (LSD) for vehicles such as automobiles, and more particularly to improving the quality of a mechanical LSD against aging deterioration.

In a vehicle drive wheel differential, when one of the drive wheels spins, the other wheel stops rotating and the drive force is not transmitted to the road surface. A sensitive mechanical LSD (multi-plate clutch LSD) is used. Referring to FIG. 5, in such a mechanical LSD 1, first, a final ring gear fixed by bolts 2b to a flange 2a protruding in the circumferential direction of a differential case 2 rotatable about a rotation axis c. A final pinion 3 at the end of the propeller shaft is meshed with 2c, and inside the differential case 2, a pressure ring 6 and a pinion cross shaft 5 having pinion gears 5a at both ends thereof rotate together with the differential case 2 around the rotation axis c. A pinion gear 5a is arranged to mesh with a left side gear 4L and a right side gear 4R respectively connected to the left and right wheels. Both ends 5b of the pinion cross shaft 5 are fitted into V-shaped cam holes formed in the edge of the pressure ring 6, and when torque acts on the pressure ring 6 in the circumferential direction, the ends 5b are pressed against each other. The pressure rings 6 on both sides of the ring 6 are configured to be displaced outward in the direction of the rotation axis c (horizontal direction in the figure) by the cam mechanism trying to escape from the V-shaped cam hole of the ring 6 . A plurality of outer claw clutch plates 7 are provided inside the differential case 2 so as to rotate together with the differential case 2. The left side gear 4L and the right side gear 4R are interposed between the outer claw clutch plates 7, respectively. When the pressure ring 6 is displaced outward in the direction of the rotation axis c in accordance with the drive torque, the outer claw clutch plate 7 and the inner claw clutch plate 8 are pressurized. They are configured to be pushed by the ring 6 into frictional engagement with each other. According to such a configuration, when rotational drive torque is transmitted from the final pinion 3 to the final ring gear 2c from the driving device (engine, motor, etc.), the differential case 2 rotates, and the pinion cross shaft 5 rotates accordingly. When the rotation is transmitted to the left side gear 4L and the right side gear 4R, when the differential case 2 rotates, reaction force to the drive torque acts from the left side gear 4L and the right side gear 4R, the pinion cross shaft tip 5b and the pressure ring 6, the pressure ring 6 is displaced outward in the direction of the rotation axis c according to the magnitude of the drive torque, and frictionally engages the outer claw clutch plate 7 and the inner claw clutch plate 8, thereby Relative rotation between the left side gear 4L and the right side gear 4R with respect to the differential case 2 is suppressed, and the differential between the left and right wheels is limited according to the drive torque. Thus, according to the above mechanical LSD, in a situation where one of the drive wheels spins, the other wheel does not stop rotating, thus achieving transmission of driving force to the road surface.

Various techniques have been proposed for the configuration of the mechanical LSD as described above. It has been proposed to provide a rotary seal between the differential case and the output shaft (the axle connected to the left and right side gears) in order to prevent the leakage of the oil to the outside of the differential case.

JP 2000-205375

In the mechanical LSD as described above, the outer claw clutch plate and the inner claw clutch plate are formed of metal plates, and are frictionally engaged at a degree corresponding to the magnitude of the driving torque. When they rub against each other, metallic friction powder is generated as described above, and if it is released outside the differential case, it may cause malfunction of valves, etc. in other peripheral devices such as the transmission. , will affect the operation. Therefore, as one countermeasure, it is conceivable to make the differential limiting mechanism portion including the clutch plate group a sealed structure as in the conventional literature. When replacing, if it is a FF (front engine, front drive) car, it is necessary to remove the transmission from the vehicle and disassemble it, or remove the drive shaft on one side of the front and replace it. It will take a lot of time and effort. Regarding this point, in the configuration where the mechanical LSD is installed in the automatic transmission for FF vehicles, if it is an open type configuration that is not sealed, the oil for the LSD is shared with the transmission, so oil replacement is not required. , It is convenient because it can be done in the same work as the fluid exchange work done at a normal dealer. Therefore, in the mechanical LSD as described above, it would be advantageous if metallic frictional powder could be prevented from being discharged outside the differential case without having to seal the differential limiting mechanism portion including the clutch plate group.

Thus, one object of the present invention is to provide an open type structure (a structure in which the differential limiting mechanism portion is not sealed and oil is shared with the transmission) in the mechanical LSD as described above. To provide a structure in which metallic frictional powder from clutch plates of outer claws and inner claws is not emitted outside a differential case even when the clutch plates are in contact with each other.

SUMMARY OF THE INVENTION According to the present invention, the above problem is solved in a vehicle mechanical limited slip differential (LSD),
a cylindrical differential case that carries a final ring gear that meshes with a final pinion at the end of a propeller shaft that transmits driving torque from the vehicle drive device and that is rotatable in the rotational direction of the left and right wheel axles;
a pinion cross shaft extending radially from an axis of rotation of the differential case inside the differential case and provided to rotate about the axis of rotation of the differential case in a direction perpendicular to the axial direction;
a pinion gear provided at the end of the pinion cross shaft;
A left side gear and a right side gear that have a gear portion that meshes with the pinion gear and shaft portions that rotatably protrude from the left and right direction of the differential case and are connected to the axles of the left and right wheels, respectively, and are rotatable in the same rotational direction as the differential case. ,
provided inside the differential case so as to be displaceable in the direction of the rotation axis of the differential case and to rotate together with the differential case; a pressure ring that is displaced outward in the left-right direction of the rotation axis of the differential case by displacing the portion in the direction of escape from the cam hole;
at least one outer pawl clutch plate fixed inside the differential case so as to extend in a direction perpendicular to the rotational axis of the differential case;
Fixed to each of the left side gear and the right side gear so as to extend in a direction perpendicular to the rotation axis of the differential case and between the outer claw clutch plate or between the outer claw clutch plate and the pressure ring at least one inner claw clutch plate interposed in
When the drive torque is transmitted to the differential case and the differential case rotates, the pressure ring and the pinion cross shaft rotate, and the left side gear and the right side gear meshing with the pinion gear rotate,
When the end portion of the pinion cross shaft is displaced in the direction to escape from the cam hole, the pressure ring is displaced laterally outward of the rotation axis of the differential case and cooperates with the outer pawl clutch plate to cooperate with the outer pawl clutch plate. A mechanical limited slip differential configured to clamp and compress inner pawl clutch plates to limit relative rotation between said inner and outer pawl clutch plates, comprising:
A non-metallic friction material is interposed between the outer claw clutch plate or the pressure ring and the inner claw clutch plate, and a stopper mechanism is provided to limit the displacement of the pressure ring with respect to the outer claw clutch plate. , when the thickness of the friction material is reduced by a predetermined width, the stopper mechanism prevents the outer claw clutch plate or the pressure ring from coming closer to the inner claw clutch plate.

In the above configuration, the "mechanical limited slip differential" may, in its basic configuration, be the torque sensitive multi-plate clutch LSD described in connection with FIG. That is, in the mechanical LSD to which the present invention is applied, in short, a pressure ring and an outer claw clutch plate are provided in the differential case, and the left side gear and the right side gear connected to the axles of the left and right wheels An inner pawl clutch plate is provided and configured to be sandwiched between a plurality of outer pawl clutch plates or between a pressure ring and an outer pawl clutch plate. Then, when the driving torque acts, the pressure ring and the outer claw clutch plate cooperate to press the inner claw clutch plate sandwiched between them against the outer claw clutch plate, and the magnitude of the driving torque increases. Indeed, the relative rotation of the inner pawl clutch plate with respect to the outer pawl clutch plate is restricted so that the left and right wheels rotate together with the differential case to a certain extent. Such situations are avoided.

In the mechanical LSD constructed as described above, according to the present invention, a non-metallic friction material is interposed between the outer claw clutch plate or the pressure ring and the inner claw clutch plate. , the outer pawl clutch plate or the pressure ring through the friction material. Further, as described above, a stopper mechanism is provided to limit the displacement of the pressure ring with respect to the outer pawl clutch plate when the drive torque is applied. The pawl clutch plate or pressure ring and the inner pawl clutch plate are configured so that they are no longer in close proximity. According to this configuration, when the thickness of the friction material is reduced by a predetermined width and the inner pawl clutch plate is about to come into direct contact with the outer pawl clutch plate or the pressure ring, displacement of the pressure ring with respect to the outer pawl clutch plate is restricted, As a result, direct frictional engagement between the inner claw clutch plate and the outer claw clutch plate or the pressure ring is prevented. Therefore, even if the mechanical LSD has an open type structure, it is possible to prevent metallic friction powder from being discharged out of the differential case from the clutch plates of the outer and inner claws. The "predetermined width" may be set so that the outer claw clutch plate and the inner claw clutch plate do not rub against each other until the thickness of the friction material is reduced by the predetermined width. It may be the sum of the thicknesses of the friction materials interposed between the pawl clutch plate and the inner pawl clutch plate or a width slightly smaller than that.

In the above configuration, various structures may be used as the stopper mechanism for limiting the displacement of the pressure ring. Then, a configuration may be employed to prevent further displacement of the pressure ring. Specifically, for example, a protruding structure formed on the inner wall of the differential case itself or a protruding member fixed to the differential case is provided, and when the pressure ring moves a predetermined distance, the protruding structure or the protruding member is applied to the pressure ring. It may be a structure that abuts on a part of the ring and prevents further displacement of the pressure ring. Alternatively, a protruding portion extending in the rotational axis direction of the differential case is formed on the outer pawl clutch plate, and when the pressure ring moves a predetermined distance, the protruding portion comes into contact with a portion of the pressure ring, thereby disengaging the pressure ring. may be a structure in which further displacement of is restrained.

In the above construction, the friction material interposed between the outer claw clutch plate or the pressure ring and the inner claw clutch plate may be made of, for example, synthetic resin fiber, carbon material, or the like. Such a friction material may be applied by being formed into a layer having an appropriate thickness and being attached to the inner claw clutch plate, the outer claw clutch plate, or both. The thickness of the friction material is gradually reduced due to compression or wear as the inner claw clutch plate is sandwiched and pressed between the outer claw clutch plate and the pressure ring (friction material Although non-metallic wear powder may be generated due to wear, it is more flexible than metallic wear powder and has less impact on the operation of other surrounding equipment.)

Thus, in the mechanical LSD of the present invention, as described above, the friction material and the stopper mechanism prevent direct frictional engagement between the inner claw clutch plate and the outer claw clutch plate or the pressure ring. Therefore, even if the mechanical LSD is of an open type structure, metal particles from the clutch plate will not be generated due to friction between the inner claw clutch plate and the outer claw clutch plate. There will be no release of abrasive friction powder. Therefore, according to the configuration of the present invention, the mechanical LSD can be mounted in an automatic transmission for FF vehicles as a case-open type structure in which the oil is common to the transmission oil, and the mechanical LSD is related. This is advantageous because it facilitates maintenance and the like.

Other objects and advantages of the present invention will become apparent from the following description of preferred embodiments of the invention.

FIGS. 1A and 1B are schematic side cross-sectional views of a pressure ring, outer claw clutch plates, and inner claw clutch plates in a mechanical LSD according to this embodiment. (A) is the state before the thickness of the friction material between the outer claw clutch plate and the inner claw clutch plate is reduced, and (B) is the state before the thickness of the friction material is reduced and the pressure is applied by the stopper mechanism. The displacement of the ring with respect to the outer pawl clutch plate is restrained. 2A and 2B are schematic side cross-sectional views of a pressure ring, an outer claw clutch plate, and an inner claw clutch plate in one aspect of the mechanical LSD according to this embodiment. As a stopper mechanism for limiting the displacement of the differential case, an example in which a projecting structure is formed on the differential case is shown. (A) is the state before the thickness of the friction material between the outer claw clutch plate and the inner claw clutch plate is reduced, and (B) is the state before the thickness of the friction material is reduced and the stopper mechanism In this state, displacement of the pressure ring with respect to the pawl clutch plate is restrained. FIGS. 3A and 3B respectively show another aspect of the mechanical LSD according to this embodiment, a stopper arranged in the differential case as part of the stopper mechanism for limiting the displacement of the pressure ring. 3(C) and 3(D) are schematic side cross-sectional views of the pressure ring, the outer claw clutch plate, and the inner claw clutch plate. FIG. (C) is the state before the thickness of the friction material between the outer claw clutch plate and the inner claw clutch plate is reduced, and (D) is the state before the thickness of the friction material is reduced and the stopper mechanism In this state, displacement of the pressure ring with respect to the pawl clutch plate is restrained. FIG. 4(A) shows another aspect of the mechanical LSD according to this embodiment, in which an outer claw clutch plate provided with a projecting portion as part of a stopper mechanism for limiting the displacement of the pressure ring. 4(B) and 4(C) are schematic side cross-sectional views of a pressure ring, an outer claw clutch plate, and an inner claw clutch plate; FIG. (B) is the state before the thickness of the friction material between the outer claw clutch plate and the inner claw clutch plate is reduced; In this state, displacement of the pressure ring with respect to the pawl clutch plate is restrained. FIG. 5 is a schematic side cross-sectional view of a typical mechanical LSD.

1...Mechanical LSD
2... Differential case 2a... Differential case flange 2b... Bolt 2c... Final ring gear 3... Final pinion 4L, 4R... Left side gear, right side gear 5... Pinion cross shaft 5a... Pinion gear 5b... Pinion cross shaft end 6... Pressure ring 7... Outer claw clutch Plate 8 Inner claw clutch plate 9a, 9b Stopper portion 10 Friction material 11 Stopper plate c Differential case rotation axis

Basic Configuration of Differential Limiting Mechanism of Mechanical LSD The configuration of the mechanical LSD of this embodiment may be basically the same as the configuration described with reference to FIG. In the basic configuration of such a mechanical LSD, in the case of this embodiment, as schematically depicted in FIG. A nonmetallic friction material 10 made of synthetic resin, carbon, or the like is interposed between the pressure ring 6 and the inner claw clutch plate 8 (not shown). Stopper mechanisms 9a, 9b are provided to limit displacement in the direction along. In the basic configuration of the stopper mechanisms 9a and 9b, as shown in the figure, the outer claw clutch plates 7 (outermost claw clutch plates) located on the left and right sides extend toward the pressure ring 6. , a stopper member 9a that displaces together with the outermost pawl clutch plate and a pressure ring 6 or a projecting portion 9b that rotates and displaces therewith. is reduced by a predetermined width Δ, the stopper portion 9b abuts against the stopper member 9a to limit further displacement of the pressure ring 6 along the rotation axis c. The distance Δ until the stopper portion 9b abuts against the stopper member 9a is equal to or slightly shorter than the thickness of the friction material 10 (the sum of the thicknesses of the respective friction materials 10). ) may be designed. The friction material 10 may be provided, for example, on both sides of the inner pawl clutch plate 8, on the side of the outer pawl clutch plate 7 facing the inner pawl clutch plate 8, or on both the inner pawl clutch plate 8 and the outer pawl clutch plate 7. , may be provided by attaching a plate-like or layer-like member made of the above materials.

In the basic configuration of this embodiment, when a driving torque is transmitted from the vehicle driving device to the differential case 2, the end of the pinion cross shaft is displaced in a direction to escape from the cam hole of the pressure ring 6. A cam acting force Ft is applied to the pressure ring 6 , thereby displacing the pressure ring 6 in the direction along the rotation axis c of the differential case 2 , and the inner claw clutch plate 8 moves between the pressure ring 6 and the outer claw clutch plate 7 . The outer claw clutch plate 7 and the inner claw clutch plate 8 are sandwiched and pressed between them, and the outer claw clutch plate 7 and the inner claw clutch plate 8 are frictionally engaged via the friction material 10, and thus the outer claw clutch plate 7 and the inner claw clutch plate 8 are relatively rotated. will be restricted. At that time, when the friction material 10 is repeatedly pressed and rubbed between the outer claw clutch plate 7 and the inner claw clutch plate 8, the friction material 10 is gradually compressed or partially worn, and the mechanical LSD is used, the thickness of the friction material 10 is gradually reduced. However, in the case of the present embodiment, as described above, when the thickness of the friction material 10 is reduced by the predetermined width Δ, the stopper member 9a comes into contact with a portion of the pressure ring 6 or the stopper portion 9b. Furthermore, the outward displacement of the differential case 2 in the direction of the rotation axis c is restricted, so that the outer claw clutch plate 7 and the inner claw clutch plate 8 are prevented from rubbing directly against each other, and the metal is removed from those plates. Therefore, it is possible to avoid the generation of abrasive wear powder. Further, since no metallic abrasion powder is generated, the mechanical LSD of this embodiment can be used in an open type structure in which oil is shared with the transmission. The reduction in the thickness of the friction material 10 is mainly caused by the compression that occurs with the use of the mechanical LSD. It has been experimentally shown that the abrasion powder has little effect on the operation of other surrounding equipment because it is made of a flexible material. When the stopper member 9a comes into contact with a part of the pressure ring 6 or the stopper portion 9b, it does not function as a torque-sensitive LSD, but functions as a normal differential gear device (in that case, , it is preferable to replace the friction material 10 at an early stage.).

Various Configurations of Stopper Mechanism The stopper mechanisms 9a and 9b in the mechanical LSD of this embodiment may be formed in various ways.

Referring to FIGS. 2A and 2B, in one embodiment of stopper mechanisms 9a and 9b, when the thickness of friction material 10 is reduced by a predetermined width Δ, a portion of pressure ring 6 or the stopper is removed. A stopper member 9a that contacts the portion 9b may be formed inside the differential case 2 . Specifically, three to six grooves are newly formed in the inner side of the differential case 2 in the direction of the rotation axis c. When the pressure ring 6 is displaced by a predetermined distance Δ from a state in which it is not displaced in the direction, the projecting portion 9b may come into contact with the end portion 9a of the groove inside the differential case 2 .

3A to 3D, in another embodiment of the stopper mechanisms 9a and 9b, when the thickness of the friction material 10 is reduced by a predetermined width Δ, the pressure ring 6 is partially or A stopper ring 11 having a stopper member 9a abutting against the stopper portion 9b may be provided further outside the outermost outer pawl clutch plate 7. As shown in FIG. Specifically, as shown in FIG. 3A, the stopper ring 11 has a link-shaped portion that concentrically abuts the outermost pawl clutch plate 7, and has three to six points on the periphery of the link-shaped portion. A stopper member 9a may be provided on the pressure ring 6 so as to extend toward the pressure ring 6 in the direction of the rotational axis c at a position on the same line as the protruding portion 9b (see FIG. 3B). When the pressure ring 6 is displaced by Δ from the state in which the pressure ring 6 is not displaced in the direction of the rotation axis c (FIG. 3C), the protruding portion 9b comes into contact with the stopper member 9a on the stopper ring 11. (Fig. 3(D)).

Referring to FIGS. 4A to 4C, in still another embodiment of stopper mechanisms 9a and 9b, a portion of the edge of outer pawl clutch plate 7 extends in the direction of rotation axis c to When the thickness of the material 10 is reduced by a predetermined width Δ, a portion of the edge of the outer pawl clutch plate 7 sequentially abuts and further abuts a portion of the pressure ring 6 or the stopper portion 9b. good. Specifically, as shown in FIG. 4A, stopper members 9a project radially from 3 to 6 points on the edge of the outer pawl clutch plate 7 and further extend in the direction of the rotation axis c. may be The sum of the lengths of the rotation axis c of the stopper member 9a is formed to be the sum of the thicknesses of the outer claw clutch plate 7 and the inner claw clutch plate 8 or slightly longer than it (FIG. 4(B)). When the width of the friction material 10 is substantially reduced, the stopper members 9a of the clutch plates 7 come into contact with each other in sequence, and the innermost tip of the stopper member 9a comes into contact with the stopper portion 9b of the pressure ring 6 ( 4(C)), thereby restricting further displacement of the pressure ring 6 in the direction of the rotation axis c.

Thus, according to the present embodiment, by providing the stopper mechanisms 9a and 9b, the displacement of the pressure ring 6 is limited when the width of the friction material is reduced due to aged deterioration, etc. Since there is no direct friction between the iron plates with the pawl clutch plate 8, the generation of metal wear powder that may cause valve malfunction etc. is suppressed, and the mechanical LSD is a transmission oil. It can also be installed in the case open type automatic transmission for FF that has become common with.

Although the above description has been made with respect to the embodiments of the present invention, many modifications and changes can be easily made by those skilled in the art, and the present invention is limited only to the above-exemplified embodiments. It will be clear that the invention is non-limiting and can be applied to a variety of devices without departing from the concept of the invention.

Claims (1)

As a vehicle's mechanical limited-slip differential,
a cylindrical differential case that carries a final ring gear that meshes with a final pinion at the end of a propeller shaft that transmits driving torque from the vehicle drive device and that is rotatable in the rotational direction of the left and right wheel axles;
a pinion cross shaft extending radially from an axis of rotation of the differential case inside the differential case and provided to rotate about the axis of rotation of the differential case in a direction perpendicular to the axial direction;
a pinion gear provided at the end of the pinion cross shaft;
A left side gear and a right side gear that have a gear portion that meshes with the pinion gear and shaft portions that rotatably protrude from the left and right direction of the differential case and are connected to the axles of the left and right wheels, respectively, and are rotatable in the same rotational direction as the differential case. ,
provided inside the differential case so as to be displaceable in the direction of the rotation axis of the differential case and to rotate together with the differential case; a pressure ring that is displaced outward in the left-right direction of the rotation axis of the differential case by displacing the portion in the direction of escape from the cam hole;
at least one outer pawl clutch plate fixed inside the differential case so as to extend in a direction perpendicular to the rotational axis of the differential case;
Fixed to each of the left side gear and the right side gear so as to extend in a direction perpendicular to the rotation axis of the differential case and between the outer claw clutch plate or between the outer claw clutch plate and the pressure ring at least one inner claw clutch plate interposed in
When the drive torque is transmitted to the differential case and the differential case rotates, the pressure ring and the pinion cross shaft rotate, and the left side gear and the right side gear meshing with the pinion gear rotate,
When the end portion of the pinion cross shaft is displaced in the direction to escape from the cam hole, the pressure ring is displaced laterally outward of the rotation axis of the differential case and cooperates with the outer pawl clutch plate to cooperate with the outer pawl clutch plate. A mechanical limited slip differential configured to clamp and compress inner pawl clutch plates to limit relative rotation between said inner and outer pawl clutch plates, comprising:
A non-metallic friction material is interposed between the outer claw clutch plate or the pressure ring and the inner claw clutch plate, and a stopper mechanism is provided to limit the displacement of the pressure ring with respect to the outer claw clutch plate. and a differential configured such that when the thickness of the friction material is reduced by a predetermined width, the stopper mechanism prevents the outer claw clutch plate or the pressure ring from coming closer to the inner claw clutch plate.

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