JP2001221320A - Differential device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a differential device which is constructed to be extra small and lightweight and obtain sufficient torque transfer volume while keeping balance in an axial direction. SOLUTION: This device is provided with a differential mechanism 5 which allocates driving force of an engine which rotates a differential case 3 to a wheel side, a clutch 11 for restricting differential and its connecting means 13, 15 which are arranged on one side and the other side of the differential mechanism 5 in an axial direction, and operating force transmission members 7, 9 which connect the clutch 11 by transmitting operating force from the connecting means 15. These operating force transmission members 7, 9 are arranged inside the differential mechanism 5 in a diameter direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a differential device having a differential limiting function.

[0002]

2. Description of the Related Art As a conventional differential device having an operation limiting function, a differential device 201 as shown in FIG. 2 is described in Japanese Patent Application Laid-Open No. 6-144040.

The differential device 201 comprises a differential case 203, a bevel gear type differential mechanism 205, main clutches 207 and 209, a push ring 211, a pilot clutch 213, a ball cam 215, an electromagnet 21
7, an armature 219 and the like.

[0004] The differential mechanism 205 includes a pinion shaft 221 and a pinion shaft 2 connected to the differential case 203.
A pinion gear 223 rotatably supported on the pinion 21 and left and right side gears 22 meshed with the pinion gear 223
5,227, etc., and the side gear 22
5, 227 are spline-connected to the left and right axles, respectively.

[0005] The main clutches 207 and 209 are arranged between the side gears 225 and 227 and the differential case 203.

[0006] The push ring 211 includes a plurality of legs 22.
9 and a ring-shaped base 231 connecting them together, and along the inner periphery of the differential case 203 (the pinion gear 2).
23), each main clutch 207, 20
9 are arranged. The base 231 faces the right main clutch 209, and each leg 229 passes between the pinion shafts 221, and the tip of the left main clutch 207.
Facing.

The pilot clutch 213 is a differential case 2
03 and the cam ring 233.

The ball cam 213 has a main clutch 209
The pressing member 235 is connected to the boss 237 of the right side gear 227 so as to be movable in the axial direction.

The electromagnet 217 has bearings 239, 239.
Through the right boss portion 241 of the differential case.

The armature 219 is arranged outside the differential case 203 so as to face the electromagnet 217. A pressing member 243 of the pilot clutch 213 is disposed inside the differential case 203, and the pressing member 243 is connected to the armature 219 by a connecting member 245 that passes through the differential case 203 and the pilot clutch 213.

When the electromagnet 217 attracts the armature 219, the pilot member 21 is pressed by the pressing member 243.
3, the ball cam 215 is operated by receiving a differential torque between the differential case 203 and the side gear 227. The cam thrust force of the ball cam 215 presses the main clutch 209 via the pressing member 235, and this pressing force is further applied to the main clutch 20 via the push ring 211.
Press 7. When the main clutches 207 and 209 are engaged, the differential of the differential mechanism 205 is limited.

Further, as described above, the differential device 201 has the center of gravity differential by arranging the pilot clutch 213 and the main clutch 209 and the main clutch 207 on the right and left sides of the differential mechanism 205 in the axial direction, respectively. It is close to the axial center of the mechanism 205, reducing axial imbalance between size and weight.

Further, for the same reason, each side gear 225,
The left and right axles connected to 227 can be easily made equal in length. If the axles can be made equal in length, the number of parts and the cost of parts can be reduced.

[0014]

However, in the conventional differential device 201, the push ring 211
Are arranged radially outward of the pinion gear 223, so that the pinion gear 223 is arranged near the rotation center axis of the differential device 201,
The side gears 225 and 227 have a small diameter.

The pinion gear 223 has the same tooth width,
The closer the arrangement location is to the rotation center axis, the smaller the diameter becomes, and the number of teeth decreases accordingly, or if the number of teeth is the same, the tooth thickness becomes thin and the strength decreases.

Further, when the arrangement location is close to the rotation center axis, the arrangement space of the pinion gear 223 is narrowed, so that the number of pinion gears 223 that can be arranged is reduced, and the torque transmission capacity of the pinion gear group is reduced.

Further, the side gears 225 and 227 also have a reduced number of teeth or a reduced tooth thickness due to the smaller diameter, resulting in reduced strength.

As described above, when the strength of the pinion gear 223 and the side gears 225 and 227 is low or the number of the pinion gears 223 is small, the differential gear 2
When the torque transmission capacity of the gear No. 01 is likely to be reduced and the torque transmission capacity is to be increased, the torque transmission capacity cannot be sufficiently increased due to the limitation of the strength of each gear.

In order to increase the torque transmission capacity, it is necessary to increase the diameter of the pinion gears 223 and the side gears 225 and 227 or to increase the number of the pinion gears 223. Accordingly, the differential device 201 also increases in diameter and weight. Therefore, the degree of freedom in terms of vehicle mounting and layout is reduced.

In the differential device 201,
By connecting the pressing member 235 to the boss 237 of the right side gear 227, the left and right side gears 225, 22
7 have different shapes and are not interchangeable, so that they cannot be shared to reduce the number of parts and the cost of parts.

A ball cam 215 is disposed radially inward, and the main clutch 209 (push ring 21
Since (1) is disposed radially outward, the offset amount Os formed between them increases, and an excessive force is applied to the pressing member 235 that transmits the cam thrust force of the ball cam 215 to the main clutch 209.

Therefore, it is necessary to increase the thickness of the pressing member 235 in order to prevent deformation, breakage, and the like, and the differential device 201 is further increased in size and weight.

Accordingly, the present invention provides a differential device which can obtain a sufficient torque transmission capacity while avoiding imbalance in the axial direction, is small in size and light in weight, and can share both side gears. Aim.

[0024]

According to a first aspect of the present invention, there is provided a differential device which rotates by a driving force of an engine, and distributes the rotation of the differential case from a pinion gear to a wheel via a pair of side gears and an axle. Differential mechanism, differential limiting clutches and coupling means arranged on one side and the other side in the axial direction of the differential mechanism, and an operating force transmitting member for transmitting the operating force of the connecting means to connect the clutch And the operating force transmitting member is disposed radially inward of the differential mechanism.

The differential mechanism transmits the driving force of the engine for rotating the differential case from the pinion gear to the wheels via the respective side gears, and the connecting means connects and operates the clutch via the operating force transmitting member. Limit differential.

Further, by disposing the clutch for limiting the differential and the coupling means on the one side and the other side in the axial direction of the differential mechanism, respectively, the center of gravity becomes closer to the axial center position,
Vibration is reduced accordingly and durability is improved.

Furthermore, by making the axles connected to the respective side gears the same length and sharing them, it is possible to greatly reduce the number of parts and the cost of parts.

In addition to this, in the differential device of the present invention, unlike the conventional example, since the operating force transmitting member is arranged radially inside the differential mechanism, the pinion gear is located at a position farther from the rotation center axis of the differential device. Can be arranged, and each side gear has a large diameter.

For example, in a bevel gear type differential mechanism, a pinion gear located far from the rotation center axis has a large diameter even with the same tooth width, so that the number of teeth can be increased. The tooth thickness is increased, and the strength is improved.

Further, since the arrangement space of the pinion gears is widened at a position far from the rotation center axis, it is possible to arrange a large number of pinion gears.

Further, the number of teeth or the thickness of each side gear increases as the diameter increases, and the strength is improved.

Thus, the strength of the pinion gears and the side gears is improved, and a large number of pinion gears can be arranged. Therefore, the differential device can obtain a sufficient torque transmission capacity without being restricted by the strength of each gear.

Further, when the torque transmission capacity is the same, each gear can be reduced in diameter by an amount corresponding to the improvement in strength, so that the differential device is also reduced in diameter and weight, thereby improving the in-vehicle mountability and the degree of freedom in layout.

According to a second aspect of the present invention, there is provided the differential device according to the first aspect, wherein the connecting means receives a torque when the pilot clutch is connected and disconnected with the pilot clutch operated and disconnected by the operating means. And a clutch which is a main clutch which is connected by being pressed by an operating force transmitting member by a cam thrust force of the cam mechanism, wherein the clutch has an operation and effect equivalent to that of the first embodiment. can get.

In addition, in this configuration in which the pressing force of the clutch is amplified by the cam mechanism, a sufficient differential limiting force can be obtained with a small-capacity main clutch, so that the differential device is further reduced in size and weight.

In this configuration in which the cam mechanism is operated by the pilot clutch, for example, a small electromagnet can be used as the operating means of the pilot clutch.
As the differential device becomes smaller and lighter,
The differential limiting force can be precisely controlled by the electromagnet, and the maneuverability, running performance, stability, and the like of the vehicle can be greatly improved.

According to a third aspect of the present invention, in the differential device according to the first or second aspect, the side gear is connected to the axle via an operating force transmitting member. The same operations and effects as those of the first or second aspect are obtained.

In addition, in this configuration in which the side gear is connected to the axle via the operating force transmitting member, the hub of the side gear can be used as the operating force transmitting member separately from the side gear.

In this case, unlike the conventional example in which the compatibility of both side gears is lost due to the shape of the hub portion, the same side gear can be used for both side gears, and the compatibility of the side gears is improved. Points and component costs can be significantly reduced.

[0040]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIG.

FIG. 1 shows a rear differential 1 (differential device) according to this embodiment.
It has three features. The rear differential 1 is arranged on the rear wheel side of an FR vehicle (front engine / rear drive vehicle). The left and right directions are the left and right directions of the vehicle, and the upper part of FIG. 1 corresponds to the front of the vehicle. Note that members without reference numerals are not shown.

The rear differential 1 includes a differential case 3, a bevel gear type differential mechanism 5, pressing members 7, 9 (operating force transmitting members),
Multi-plate type main clutch 11 (differential limiting clutch), multi-plate type pilot clutch 13, ball cam 1
5 (cam mechanism), an armature 17, an electromagnet 19 (operation means), a controller and the like.

The differential case 3 is housed in a differential carrier, and the differential carrier is filled with oil.
A ring gear is fixed to the differential case 3 with bolts, and the ring gear meshes with a drive pinion gear formed integrally with the drive pinion shaft. The drive pinion shaft is connected to the propeller shaft via a joint.

The driving force of the engine drives the differential case 3 from the transmission via these propeller shafts, drive pinion shafts and the like.

The differential mechanism 5 includes four pinion shafts 2
1, a pinion gear 23 rotatably supported on each pinion shaft 21, and left and right side gears 25 and 27 meshed with each pinion gear 23, and the like. The side gears 25 and 27 use the same gear in opposite directions.

The pinion shafts 21 are radially arranged at regular intervals around the block 29. The radially inner end of each pinion shaft 21 is engaged with and fixed to the through hole 31 of the block 29, and the outer end is engaged with the through hole 33 of the differential case 3 and is fixed by the detent pin 35. ing.

Between each pinion gear 23 and the differential case 3, the centrifugal force of the pinion gear 23 and the side gears 25,
A spherical washer 37 is provided which receives a meshing reaction force of the pinion gear 23 generated by meshing with the pinion gear 27. The frictional resistance generated between the pinion gear 23 and the spherical washer 37 by these forces becomes the differential limiting force of the differential mechanism 5 as described below.

The driving force of the engine for rotating the differential case 3 is distributed from the pinion shaft 21 and the pinion gear 23 to the left and right rear wheels via the side gears 25 and 27, the pressing members 7, 9 and the axle, respectively. Further, for example, when a driving resistance difference occurs between the rear wheels on a rough road, the pinion gear 2
3, the driving force of the engine is differentially distributed to the left and right sides.

The pressing members 7, 9 are provided with side gears 25, 27.
Are arranged radially inward, and their ends penetrate the block 29 and abut against each other. The pressing members 7, 9 are connected to the side gears 25, 27 via spline portions 39, 41 on the outer periphery, and spline portions 43, 45 on the inner periphery.
Respectively connected to the left and right axles.

The main clutch 11 is disposed between the differential case 3 and the left pressing member 7, and the pressing member 7 is formed with a pressing portion 47 of the main clutch 11.

The pilot clutch 13 includes a ring 49
And the cam ring 51. The ring portion 49 is made of stainless steel and is welded to the differential case 3.

The ball cam 15 is disposed between a cam portion 53 formed on the right pressing member 9 and the cam ring 51. A thrust bearing 55 receiving a cam reaction force of the ball cam 15 is provided between the cam ring 51 and the differential case 3.
And a washer 57 are disposed.

The armature 17 includes the pilot clutch 1
3 is located on the left side.

The core 59 of the electromagnet 19 is fixed to the differential carrier by a supporting member, and the differential case 3
Is supported by a bearing 63 on a right boss 61 of the vehicle, and its lead wire is led out of the differential carrier via a grommet and connected to a vehicle-mounted battery.

The right boss 61 and the wall 65 and the core 59 which are integral with each other.
An air gap 67 is formed between them. Wall 6
Reference numeral 5 is made of a magnetic material and forms a part of a magnetic circuit. The wall portion 65 is divided into a radially outer portion and an inner portion by a ring 69 of a nonmagnetic material such as stainless steel, and openings 71 are formed in each clutch plate of the pilot clutch 13 at equal intervals in the circumferential direction. I have. Electromagnet 19
The magnetic force is prevented from being short-circuited by the ring 69 and the opening 71, and is effectively concentrated on the armature 17.

The controller detects turning based on the vehicle speed, steering angle, lateral G, and the like, or performs excitation of the electromagnet 19, control of the excitation current, and stop of excitation according to the road surface condition and the like.

When the electromagnet 19 is excited, a magnetic loop 73 is formed, the armature 17 is attracted, and the pilot clutch 13 is pressed and fastened. When differential rotation occurs in the differential mechanism 5 with the pilot clutch 13 engaged, the differential case 3 and the pressing member 9 (side gear 2)
The differential torque during 7) is applied to the ball cam 15, and the generated cam thrust force presses the main clutch 11 via the pressing members 9 and 7 to fasten it.

The differential of the differential mechanism 5 is controlled by the main clutch 11
Thus, the force is limited between the differential case 3 and the left side gear 25 (the pressing member 7), and is limited by frictional resistance between the pinion gear 23 and the spherical washer 37.

This differential limiting force improves the straight running stability of the vehicle, and when one of the rear wheels idles on a rough road, or when starting or accelerating, a driving force is sent to the other rear wheel. As a result, traveling performance on rough roads is improved, and startability and acceleration are improved, and the stability of the vehicle at the time of start and acceleration is improved.

When the exciting current of the electromagnet 19 is controlled, the cam clutch thrust force of the ball cam 15 changes due to the slip of the pilot clutch 13, and the frictional resistance of the main clutch 11 changes to allow a differential, thereby improving the turning performance of the vehicle. Smooth turning can be performed.

When the excitation of the electromagnet 19 is stopped, the pilot clutch 13 is released, the cam thrust force of the ball cam 15 disappears, and the differential limitation by the main clutch 11 stops.

The differential case 3 is provided with openings 75, 77, 77, through which the oil of the differential carrier flows into and out of the differential case 3. The inflowing oil flows into the main clutch 11, the meshing portion and sliding portion of each gear (differential mechanism 5), the spline portions 39, 41, 43, and 45, the sliding portion between the pinion gear 23 and the spherical washer 37, the ball cam 1 and the like.
5, pilot clutch 13, thrust bearing 55
And is supplied to a washer 57 and the like to lubricate and cool them. In particular, the openings 77 provided in the ring portion 49 effectively lubricate and cool the pilot clutch 13.

Thus, the rear differential 1 is configured.

As described above, the pinion gear 23 of the rear differential 1 is farther from the rotation center axis of the rear differential 1 by arranging the pressing members 7 and 9 radially inside the differential mechanism 5 as described above. It becomes possible to arrange in a place.

As described above, the pinion gear 23 disposed far from the rotation center axis has a large diameter even with the same tooth width, so that the number of teeth can be increased, or if the number of teeth is the same, the tooth thickness can be increased. And the strength is improved.

Further, since the arrangement space of the pinion gear 23 is widened at a position far from the rotation center axis, it is possible to arrange a large number of pinion gears 23 accordingly.

Thus, the strength (torque transmission capacity) of the entire side gear group 23 is greatly improved.

Further, by disposing the pinion gear 23 at a position far from the rotation center axis, the side gear 25,
Since the diameter of 27 also becomes large, the number of teeth increases accordingly, or the tooth thickness increases, and the strength improves.

As described above, the strength of the pinion gear 23 and the side gears 25 and 27 is improved, or a large number of pinion gears 23 can be arranged.
In this case, a sufficient torque transmission capacity can be obtained without being limited by the strength of each gear.

When the torque transmission capacity is the same, each gear can be reduced in diameter by an amount corresponding to the improvement in strength.
In this case, the diameter becomes smaller and the weight becomes smaller, so that the vehicle mountability and the degree of freedom in layout are improved.

In the rear differential 1 in which the side gears 25 and 27 and the axle are connected via the pressing members 7 and 9, the side gears and the hub are separated from each other, and these hubs are used for the pressing members 7 and 9. Configuration.

Therefore, the hub 237 is attached to the side gear 227.
Unlike the conventional example in which the compatibility of the two side gears 225 and 227 is lost due to the formation of the side gears, the same side gears can be shared by the side gears 25 and 27 as described above, so that the number of parts and the cost of parts are greatly reduced. I do.

The offset amount Os between the ball cam 215 and the main clutch 209 (push ring 211)
In the rear differential 1 in which the pressing members 7 and 9 are arranged radially inward of the differential mechanism 5, unlike the conventional example in which the pressing force is large, the offset amount Os between the ball cam 15 arranged radially inward and the pressing members 7 and 9 is different. Since it is extremely small, no excessive force is applied to the pressing members 7 and 9.

Therefore, it is not necessary to increase the thickness of the pressing members 7 and 9 in order to prevent deformation and the like, and it is possible to avoid an increase in the size and weight of the rear differential 1.

Further, the main clutch 11 is disposed on the left side of the differential mechanism 5, and the pilot clutch 13 and the ball cam 15, which are connecting means of the main clutch 11, are connected to the differential mechanism 5.
, The center of gravity of the rear differential 1 is closer to the dimensional axial center, and the axial imbalance is reduced.

Therefore, the vibration of the rear differential 1 is reduced accordingly, and the durability is improved.

Further, the axles connected to the side gears 25 and 27 can be made equal in length, and by sharing them, the number of parts and the cost of parts can be reduced in addition to the common use of the side gears 25 and 27. Is greatly reduced.

Further, since the pressing force of the main clutch 11 is amplified by the ball cam 15, a sufficient differential limiting force can be obtained even if the main clutch 11 has a small capacity, and the rear differential 1 is further reduced in size and weight.

In this configuration in which the ball cam 15 is actuated by the pilot clutch 13, a small electromagnet 19 can be used as the operating means of the pilot clutch 13, and the rear differential 1 is further reduced in size and weight.

Further, the differential limiting force can be precisely controlled by the electromagnet 19, so that the controllability, running performance, stability and the like of the vehicle can be greatly improved.

The pressing portion 47 of the main clutch 11 formed on the pressing member 7 may be provided separately from the pressing member 7.

In the differential device of the present invention, the differential mechanism is not limited to the bevel gear type, and for example, a differential mechanism for connecting both side gears via a pinion gear slidably and rotatably housed in a housing hole of a differential case. A moving mechanism, a planetary gear type differential mechanism, or a differential mechanism using a worm gear may be used.

In any case, the diameters of the pinion gear and the side gear are increased without increasing the diameter of the differential device.
And it becomes possible to increase the number of pinion gears,
The strength of each gear is improved, and the above-described functions and effects can be obtained. In the case of a planetary gear type differential mechanism, a pinion carrier that supports the pinion gear and an internal gear correspond to a side gear.

In the structure of the first aspect, the connecting means of the clutch for limiting the differential may be a hydraulic actuator using hydraulic pressure or pneumatic pressure.

Also, in the structure of the second aspect, similarly to the operation means of the pilot clutch, a fluid pressure actuator may be used instead of the electromagnet.

[0086]

According to the differential device of the present invention, the strength of the pinion gear group and the side gears is improved, and a sufficient torque transmission capacity can be obtained.

If the diameter of each gear is reduced by an amount corresponding to the improvement in strength, the diameter of the differential device becomes smaller and lighter, thereby improving the mountability and the degree of freedom in layout.

According to the differential device of the second aspect, the same effect as the configuration of the first aspect can be obtained.

According to the differential device of the third aspect, the same effect as the configuration of the first or second aspect can be obtained, and if the hub separate from the side gear is used as the operating force transmitting member, the same side gear can be used. Since both side gears can be used in common, the number of parts and the cost of parts are greatly reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a sectional view of a conventional example.

[Explanation of symbols]

 Reference Signs List 1 rear differential (differential device) 3 differential case 5 bevel gear type differential mechanism 7, 9 pressing member (operating force transmitting member) 11 main clutch (differential limiting clutch) 13 pilot clutch 15 ball cam (cam mechanism) 19 electromagnet (operation Means) 23 Pinion gear 25, 27 Side gear

Claims (3)

[Claims] 1. A differential case that is rotated by the driving force of an engine, a differential mechanism that distributes the rotation of the differential case to a wheel side from a pinion gear via a pair of side gears and an axle, and one axial side of the differential mechanism. A differential limiting clutch and a coupling means arranged on the other side, and an operating force transmitting member for transmitting the operating force of the connecting means to connect the clutch, wherein the operating force transmitting member is a differential mechanism. A differential device, wherein the differential device is disposed radially inward of the device. 2. The clutch according to claim 1, wherein the connecting means comprises a pilot clutch intermittently operated by the operating means, and a cam mechanism which operates by receiving a torque when the pilot clutch is connected. Is a main clutch which is pressed and connected via an operating force transmitting member by a cam thrust force of the cam mechanism. 3. The differential device according to claim 1, wherein the side gear is connected to the axle via an operation force transmitting member.