JP2001355706A - Differential device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ball-type differential device capable of obtaining the differential limiting force corresponding to the input torque with a simple constitution. SOLUTION: A cam face 34 pressing a ball 32 in the direction of a center of rotation of the differential device corresponding to the torque inputted from an input shaft 17, is formed on a ball holding plate 19, on the other hand, a contact face with the ball 32 of an output plate 30 is formed into taper faces 30d expanded in the outside diameter direction of the output plate, whereby the ball 32 is pushed out in the direction of the center of rotation by the cam face 34 caused by the displacement of the ball holding plate 19 and the output plate 30 produced in accordance with the increase of the input torque to the differential device, and the taper faces 30d on both sides are pushed and opened. Whereby both output plates 30 are outwardly moved, the frictional force to a differential case 14 of each output plate is increased, and the input characteristic that the energizing force is increased in accordance with the input torque inputted from the differential case side can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a differential gear,
In particular, the present invention relates to a differential device that can obtain a differential limiting force according to a torque input from a differential case.

[0002]

2. Description of the Related Art Conventionally, differentials for driving wheels of automobiles are known as differentials. As a differential for driving wheels of an automobile, a differential mechanism is generally configured by combining four bevel gears,
In order to reduce costs, etc., the differential mechanism
There has been proposed a ball type differential device comprising a ball and an output plate arranged to be in pressure contact with the ball. One example is disclosed in JP-A-10-169758.

The differential mechanism of this differential device will be described with reference to FIG. 8. In FIG. 8, reference numeral 01 denotes a ball holding plate, and the ball holding plate 01 has a bolt hole 0.
2 is attached to a ring gear (not shown) by bolts inserted through the ring gear 2. The ball holding plate 01 is provided with four accommodation chambers 03 at equal intervals. The accommodation room 03 penetrates the ball holding plate 01 in the axial direction, so that the ball 04 can rotate in each accommodation room 03, and each of the opposing surfaces of a pair of left and right output plates 05. Is housed so as to be able to abut. Each output plate 05 is provided with an output shaft 06, and further provided with a disc spring (not shown) which functions to press both output plates 05 toward the respective balls 04. Have been.

In the above configuration, when an input shaft (not shown) is rotated by receiving the driving torque of the engine, the rotation rotates the ball holding plate 01 via the ring gear. When the ball holding plate 01 rotates, the ball 04 in the storage chamber 03 also rotates. Here, since the accommodation room 03 in which the ball 04 is accommodated is located at a position radially away from the center of rotation, the ball 04 is located above the center of rotation when the ball holding plate 01 rotates. Will orbit. The arrow A in FIG. 8 indicates the ball holding plate 01.
Shows the rotation direction.

[0005] On both sides of the ball 04, a pair of output planes is provided.
When the ball 04 revolves, the output plates 05 on both sides of the ball 04 receive a frictional force in the same direction when the ball 04 revolves. Plate 05 is rotated in the same direction. Each output plate 0
5 has an output shaft 06 attached to each.
Both drive wheels of the car rotate at the same rotational speed, and the car goes straight.

When the car is going to bend while the car is running, a difference occurs in the external load torque applied to the drive wheels due to a difference in rotation between the inner wheel and the outer wheel. You will be twisted towards. Here, since the ball 04 is rotatably accommodated in the accommodation room 03 and can rotate, each ball 0
4 rotate in the direction indicated by the arrow B. Each ball 0
When the wheels 4 rotate in the directions indicated by the arrows B, a frictional force W is applied to the two output plates 05 in opposite directions, so that the two output plates 05 are rotated in opposite directions.

As described above, when the curve is going to bend, the ball 04 rotates while revolving, and the rotation of one of the output shafts 06 is added to the revolving rotation, and the other output shaft 06 is rotated. , The rotation is subtracted from the revolving rotation, so that a rotation difference occurs between the two output shafts 06. In this way, since both output shafts 06 are differential, the vehicle can smoothly travel the curve with a difference in rotation between the inner and outer wheels.

[0008]

By the way, in the above-mentioned conventional differential, the ball 04 pushes a disc spring as urging means between a pair of output plates 05 arranged on both sides thereof. It is clamped with friction based on pressure. Therefore, the slip load of the ball 04, that is, the engagement torque of the differential gear is determined by the pressing force at the time of the initial setting of the urging means. Therefore, in this differential device, the engagement torque is constant irrespective of the torque input to the device, and as a result, the input characteristic in which the urging force of the urging means increases according to the torque input to the device, That is, there is an inconvenience that a differential limiting force corresponding to the input torque cannot be obtained.

As a result, this differential device cannot exhibit a non-slip function, that is, a function of automatically stopping the differential function as needed. Therefore, there is a problem that it is difficult to escape when one of the drive wheels slips on a muddy road or the like or when one of the drive wheels similarly slips on a snowy road.

An object of the present invention is to provide a ball type differential as described above which can obtain a differential limiting force in accordance with an input torque with a simple structure.

[0011]

SUMMARY OF THE INVENTION In order to solve the above-mentioned conventional problems, a first aspect of the present invention is to provide a differential case which rotates by receiving a torque input from an input shaft via a ring gear, and A differential mechanism disposed in the differential case, the differential mechanism being disposed on the same axis and rotatably supported by the differential case, and a pair of output shafts; A shaft having an opposing surface attached to each inner end of the shaft and disposed so as to oppose each other, and a disk portion disposed on the back of the opposing surface opposite to the differential case; A set of output plates, a ball holding plate attached to the differential case so as to be interposed between the opposing surfaces of the output plates, and a pair of the output plates. Plural pieces rotatably held on the ball holding plate so as to be in contact with the respective opposing surfaces. In a differential device formed by a ball and a preload spring for pressing the output plates in directions approaching each other, the differential mechanism operates in accordance with a torque input from the input shaft. It is characterized by having an input characteristic in which the urging force for pressing the output plate against the differential case via the ball increases.

According to the first aspect of the present invention, the differential mechanism presses the output plate to the differential case via a ball in accordance with the torque input from the input shaft. Since the input characteristics in which the urging force is increased are provided, differential characteristics can be obtained according to the input torque.

A second aspect of the present invention comprises a differential case that rotates by receiving a torque input from an input shaft via a ring gear, and a differential mechanism disposed in the differential case. A pair of output shafts arranged on the same axis and rotatably supported by the differential case, and attached to respective inner ends of the output shafts so as to face each other. A pair of output plates having a facing surface to be disposed, a disk portion disposed so that the back surface on the back side of each of the facing surfaces faces the differential case, and a pair of output plates. A ball holding plate attached to the differential case so as to be interposed between the opposing surfaces, and the ball holding plate so as to be able to contact the opposing surfaces of the two output plates. A plurality of balls rotatably held on a plate and the output plates in a direction approaching each other. And a cam surface for pressing the ball in the direction of the rotation center of the differential device in accordance with the torque input from the input shaft. The output plate is formed on a holding surface, and the ball contact surface of the output plate is formed on a taper surface that expands in the outer diameter direction of the output plate. I do.

According to a second aspect of the present invention, there is provided the above-described structure, and as the input torque to the differential device increases, the ball-type motor is driven.
A displacement occurs between the ball holding plate and the output plate, and the displacement causes the ball to be pushed out by the cam surface in the direction of the center of rotation. This movement of the ball causes the taper surfaces on both sides to move. Is pushed open. As a result, both output plates move outward, and the frictional force of each output plate against the differential case increases due to the outward movement of both output plates. As a result, it is possible to obtain an input characteristic in which the urging force increases in accordance with the input torque input from the differential case.

According to a third aspect of the present invention, in the first or second aspect of the present invention, a friction plate is interposed between the rear surface of the disk portion of each output plate and the differential case. It is characterized by having been done. Therefore, according to the third aspect of the present invention, the frictional force between the differential case and the output plate can be increased, and as a result, the contact area between the friction plate and the differential case can be reduced. As a result, the size of the differential device can be reduced.

Each of the above inventions is a ball type in which a differential mechanism is constituted by a plurality of balls and an output plate disposed so as to be pressed against the balls. Since this is a differential device, it is possible to reduce the manufacturing cost as compared with a differential device in which a bevel gear is combined.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A description will now be given of a differential device according to an embodiment of the present invention shown in FIGS. FIG.
1 is a front view showing an assembled state of an embodiment of the differential according to the present invention, FIG. 2 is a side view showing an assembled state of the differential, and FIG. 3 is a sectional view taken along line AA of FIG. FIG. 4 is a cross-sectional view taken along line BB of FIG. 2, FIG. 5 is an assembly view of main parts of the differential, FIG. 6 is an exploded side view of main parts of the differential, and FIG. It is a figure which expands and shows C arrow part.

The main body housing 11 provided in the differential device 10 is composed of a pair of left and right bowl-shaped members 11a and 11b and a bolt 11c for connecting each flange portion of both bowl-shaped members 11a and 11b. A reinforcing rib 14c protrudes from an outer surface of the bowl-shaped member 11b. The main body housing 11 has a pair of bearing holes 1 on the left and right sides in FIG.
The rotating case 14 is rotatably supported by bearings 13, 13 mounted on the bearing holes 12, 12, respectively. An input bearing 15 is provided below the main housing 11 in FIG.
Is formed by a bearing hole 20, and an input shaft 17 is rotatably supported by a bearing 16 attached thereto in a direction orthogonal to the rotation axis of the rotation case 14.

A bevel gear 18 is attached to the tip of the input shaft 17, and a drive shaft from an engine (not shown) is connected to the input shaft 17 on the side opposite to the bevel gear 18. Rotating case 1
Reference numeral 4 denotes a casting cap 14A, and a casting case 14 which is to be hollow-connected to the inward opening of the cap 14A.
B, and an internal space 24 is formed inside the rotating case 14.

Between the case 14B and the cap 14A,
A donut-shaped ball holding plate 19 is provided. Protrusions 14a and 14b are formed on the cap 14A and the case 14B in a direction opposite to the direction of the ball holding plate 19, and the protrusions 14a and 14b And the rotating case 14 is rotatably supported by the main body housing 11.

A flange 21 is formed on the case 14B, and a bevel gear-shaped ring gear 22 is attached to the flange 21 with bolts 23.
And are engaged. The meshing between the bevel gear 18 and the ring gear 22 has a function of not only changing the rotation direction by 90 ° but also reducing the speed by the difference in the number of teeth.

The inner space 24 of the rotating case 14 has a bore.
The inner space 24 is divided into two chambers by a metal holding plate 19 and formed into two internal spaces.
a, 14b are formed at the center. In addition, insertion hole 2
Flat receiving portions 26, 26 parallel to the ball holding plate 19 are formed at the edges of the inner space 24 on the side of the inner space 24, and two disc springs 27, 27 are formed on the receiving portions. It is arranged.

A pair of left and right output shafts 28 are arranged on the rotation case 14 on the same axis as the rotation shaft with the ball holding plate 19 as the center. Each output shaft 28 extends into the internal space 24 through the bearing hole 12 of the main body housing 11 and the insertion hole 25 of the rotating case 14, and a spline provided at the inner end of each output shaft 28. 2
Output plates 30 and 30 are attached to the output plates 9 through 9.

Each of the output plates 30 is urged in a direction approaching each other, that is, inward, by disc springs 27, 27 via friction plates 31, 31 disposed outside thereof. Have been. And cap 14
A, the case 14B, the friction plates 31, 31, and the ball holding plate 19 are composed of a male screw 14e formed on the outer periphery of the cap 14A and a female screw 14g formed on the inner peripheral surface of the case 14B. They are integrated by connection.

As shown in FIG. 4, the ball holding plate 19 is formed of a thick plate having a donut shape in plan view, and a ball 32 is housed and held on an inner peripheral surface thereof. A ball holding portion 33 is formed. Each ball holder 33
Are formed on the inner peripheral surface of the ball holding plate 19, and they are evenly arranged at the same distance from the center of rotation of the rotating case 14, and the ball holding plate 19 -G1
9 in the axial direction. Projections 19a are provided at 90 ° intervals on the outer peripheral portion of the ball holding plate 19, while concave portions 14 are provided at 90 ° intervals on the inner peripheral surface of the case 14B.
d are formed, each projection 19a is fitted into the corresponding recess 14d, and the ball holding plate 19 is
B can be assembled.

As shown in FIG. 7, each of the balls 32 is held in a state in which it protrudes from the openings 33a, 33a on both sides of the ball holding portion 33 to both sides of the ball holding plate 19. Part 3
3 and is rotatably held between the ball holding portion 33 and a tapered surface 30d of the output plate 30 described later. In addition, each of the adjacent
A cam surface 34 having a shape protruding toward the center of rotation is formed between the screw holders 33.

The output plate 30 is composed of a donut-shaped disk portion 30a and a cylindrical shaft-fitting portion 30b attached to a central hole of the disk portion 30a so as to be orthogonal to the hole. ing. And the shaft fitting portion 30 of each disk portion 30a
Side to which b is not attached (hereinafter referred to as “opposed surface”)
A set of output plates 3 are arranged so that the output plates 30c face each other.
Numerals 0 are attached to the output shaft 28 via splines 29 at the respective shaft fitting portions 30b.

FIG. 7 shows a radially outer edge of each facing surface 30c.
As shown in FIG. 5, a tapered surface 30d extending in the outer diameter direction is formed, and a V-shaped ball receiving portion 30e is formed by a pair of opposed tapered surfaces 30d. I have. Further, friction plates 31, 31 are provided on the side surface opposite to the opposed surface of the disk portion 30a, that is, on the back surface 30f.
Are pressed by the spring force of the disc springs 27, 27.

Each of the friction plates 31 is formed of a disk having a donut shape in plan view, and each of the central circular holes 31a has a shaft fitting portion 30b of each of the output plates 30. And is supported by being fitted to the outer peripheral surface thereof. Further, projections 31b are provided on the outer periphery at 90 ° intervals. And this projection 31b is the case 14B.
The friction plate 31 is fitted into the recesses 14d formed at 90 ° intervals on the inner peripheral surface of the case 14 so that the friction plate 31 is assembled to the case 14B.

Each of the disc springs 27 is formed in a donut shape in plan view, and each of the center circular holes 27a is fitted to the outer peripheral surface of the shaft fitting portion 30b of the output plate 30, and A spring 27 is mounted on the case 14B. In this embodiment, each output plate 30 is connected to each disc spring 2 via each friction plate 31.
7 is pressed. Friction play
By providing the plate 31, the frictional force between the differential case 14 and the output plate 30 can be increased, and as a result, the contact area between the output plate 30 and the differential case 14 can be reduced. It becomes possible to make the differential 10
Can be reduced in size.

The operation of the differential 10 will be described. While the vehicle is traveling straight, the operating mechanism operates in the same manner as the conventional differential. That is, when the input shaft 17 is rotated by receiving a driving torque of an engine (not shown), the rotation is transmitted through the ring gear 22 to the ball holding plate 19.
Rotates. When the ball holding plate 19 rotates, the ball 32 in the ball holding section 33 also rotates. Here, since the ball holding portion 33 in which the ball 32 is housed is located radially away from the center of rotation of the case 14, the ball 32 is a ball holding plate. When 19 rotates, it revolves around the center of rotation. Ball 3
The revolution direction of No. 2 is the same as the arrow A in FIG.

On both sides of the ball 32, a pair of output planes is provided.
When the ball 32 revolves, the output plates 30 on both sides are in contact with each other.
Receives the frictional force in the same direction, and both output shafts 28 are rotated in the same direction. In this way, both drive wheels of the vehicle rotate at the same rotational speed and the vehicle goes straight.

When the vehicle tries to turn the curve, a difference in the external load torque applied to the drive wheels occurs due to the rotation difference between the inner wheel and the outer wheel, and the two output shafts 28 are screwed in opposite directions due to the torque difference. And each ball 3
2 rotates in the same direction as that of the conventional example. Ball 3
When the wheel 2 rotates, it is pressed against both sides of the ball 32 and the output plate 30 is subjected to frictional forces in opposite directions.
Both output shafts 28 are rotated in opposite directions.

As described above, when the vehicle tries to turn the curve, the ball 32 rotates while revolving, and the rotation of one of the output shafts 28 is added to the rotation of the output shaft 28, and the other output shaft 28 is rotated. The rotation of the shaft 28 is subtracted from the revolving rotation, and a rotation difference is generated between the two output shafts 28, so that the vehicle can smoothly travel on the curve due to the rotation difference between the inner and outer wheels. .

During the operation described above, each ball 32 receives a load in the axial direction by the cam surface 34 of the ball holding plate 19, and the load forms a ball receiving portion 30e. Taper surfaces 30d, 30d.
Acts outwardly. Between the back of both output plates 30 and cap 14A and case 14B,
Since the friction plates 31 and 31 are provided, respectively, the rotation of the cap 14A and the case 14B, that is, the rotation of the differential case 14, causes the pressing force to the outside of each output plate 30 and the friction plate to rotate. The differential force is transmitted to the output plate 30 by the frictional force of the plates 31, 31.

4 and 7 show a state where the input torque is 0 or small, that is, an initial state. In this initial state, the pre-spring force of the disc spring 27 acts on the taper surfaces 30d and 30d forming the ball receiving portion 30e, and the ball 32 holds the ball by the pre-spring force. Play
In a state where it is pressed against the cam surface 34 of the door 19. In this state, as the input torque to the differential 10, that is, the driving force to the output shaft 28 increases, the ball 32 and the tape
Slip occurs between the bearing surfaces 30d and 30d, and a displacement occurs between the ball holding plate 19 and the output plate 30. This shift increases as the input torque to the differential device 10 increases.

When the above-mentioned displacement occurs, the ball 32 is pushed by the cam surface 34 and pushed out toward the center of rotation, that is, upward in FIG. With this movement of the ball 32,
The taper surfaces 30d on both sides are pushed open, whereby the output plates 30, 30 move outward.

The outward movement of both output plates 30, 30 increases the frictional force of each output plate 30 on cap 14A and case 14B. Further, since this frictional force and the amount of outward movement of both output plates 30, 30 are in a proportional relationship, in this differential device 10, in accordance with the input torque input from the differential case 14 side. An input characteristic in which the urging force increases is obtained.

When the input torque input from the differential case 14 further increases and the ball 32 is pushed further between the taper surfaces 30d, 30d from the cam surface 34,
The frictional force between the ball 32 and the tapered surfaces 30d, 30d on both sides becomes extremely large, and the ball 32 is locked between the tapered surfaces 30d, 30d by this large frictional force. As a result, the ball 32 stops rotating.

When the ball 32 enters the rotation stop state, the differential function is not performed, and the differential device 10 enters the non-slip state. In this manner, the differential device 10 of this embodiment can obtain a differential limiting force in accordance with the input torque with a simple configuration. As a result, while the vehicle is running, one of the two A differential device that solves the problem that it is difficult to escape when a wheel slips or one of the drive wheels similarly slips on a snowy road or the like can be obtained at low manufacturing cost.

If necessary, the disc spring 27 may be provided only on one of the output plates, and the ball 32 may be moved so that only one of the output plates is pushed open.

[Brief description of the drawings]

FIG. 1 is a front view showing an assembled state of an embodiment of a differential gear according to the present invention.

FIG. 2 is a side view showing an assembled state of the differential device.

FIG. 3 is a sectional view taken along line AA of FIG. 1 and shown together with a main body housing.

FIG. 4 is a sectional view taken along line BB of FIG. 2;

FIG. 5 is an assembly diagram of a main part of the differential device.

FIG. 6 is an exploded side sectional view of a main part of the differential device.

FIG. 7 is an enlarged view showing a part viewed from an arrow C in FIG. 3;

FIG. 8 is an exploded perspective view of a differential mechanism in a conventional differential.

[Explanation of symbols]

10: Differential device, 11: Body housings 11, 12; Bearing holes, 13: Bearing, 14A: Cap, 14
B: Case, 16: Bearing, 17: Input shaft, 18:
Bevel gear, 19: ball holding plate, 21: flange, 2
2: ring gear, 23: bolt, 24: internal space, 2
5: insertion hole, 26: receiving part, 27: disc spring, 28: output shaft, 29: spline, 30: output plate, 30a:
Disc part, 30b: shaft fitting part, 30c: facing surface, 30d:
Tapered surface, 30e: ball receiving portion, 30f: back surface, 3
1: Friction plate, 32: Ball, 33: Ball
Holding portion, 34: cam surface.

────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] June 15, 2000 (2006.1.
5)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Explanation of sign

[Correction method] Change

[Correction contents]

[Description of Signs] 10: Differential device, 11: Main body housings 11, 12; Bearing holes, 13: Bearings, 14A: Cap, 14
B: Case, 16: Bearing, 17: Input shaft, 18:
Bevel gear, 19: ball holding plate, 20: bearing hole,
21: collar, 22: ring gear, 23: bolt, 24:
Internal space, 25: insertion hole, 26: receiving portion, 27: disc spring, 28: output shaft, 29: spline, 30: output plate, 30a: disk portion, 30b: shaft fitting portion, 30c: facing surface, 30d: tapered surface, 30e: ball receiving portion, 30
f: back, 31: friction plate, 32: bo
, 33: ball holding portion, 34: cam surface.

[Procedure amendment 2]

[Document name to be amended] Drawing

[Correction target item name] Figure 3

[Correction method] Change

[Correction contents]

FIG. 3 ────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] June 21, 2000 (2006.2.
1)

[Procedure amendment 1]

[Document name to be amended] Drawing

[Correction target item name] Fig. 6

[Correction method] Change

[Correction contents]

FIG. 6

Claims (3)

[Claims] 1. A differential case, which rotates by receiving a torque input from an input shaft via a ring gear, and a differential mechanism disposed in the differential case, wherein the differential mechanisms are the same. A pair of output shafts disposed on the axis and rotatably supported by the differential case; a pair of opposing surfaces attached to respective inner ends of the respective output shafts and disposed to face each other; A pair of output plates each having a disk portion disposed so that the back surface on the back side of each opposing surface is opposed to the differential case, and interposed between the opposing surfaces of both output plates. And a ball holding plate attached to the differential case so as to be able to come into contact with each of the opposing surfaces of the two output plates.
Wherein the differential plate includes a plurality of balls rotatably held on a wheel holding plate and a preload spring for pressing the output plates in directions approaching each other. A moving mechanism changes the output plate through the ball in accordance with the torque input from the input shaft, and the differential plate
A differential device characterized by having an input characteristic in which an urging force for pressing against an input is increased. 2. A differential case, which rotates by receiving a torque inputted from an input shaft via a ring gear, and a differential mechanism disposed in the differential case, wherein the differential mechanisms are the same. A pair of output shafts disposed on the axis and rotatably supported by the differential case; a pair of opposing surfaces attached to respective inner ends of the respective output shafts and disposed to face each other; A pair of output plates having a disk portion disposed so that the back surface on the back side of each opposing surface is opposed to the differential case, and interposed between the opposing surfaces of both output plates; And a ball holding plate attached to the differential case so as to be able to come into contact with each of the opposing surfaces of the two output plates.
A differential spring formed by a plurality of balls rotatably held on a wheel holding plate and a preload spring for pressing the output plates in directions approaching each other. A cam surface for pressing the ball in the direction of the center of rotation of the differential device according to the torque input from the shaft is provided on the ball.
The output plate is formed on a taper surface that expands in the outer diameter direction of the output plate while the ball contact surface of the output plate is formed on the tape holding plate. And the differential device. 3. The friction plate according to claim 1, wherein a friction plate is interposed between the back surface of the disk portion of each of the output plates and the differential case. 4. The differential device according to claim 1.