JPH11108155A - Differential device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a differential device capable of generating a differential restricting force which remains stable at all times even in a low speed rotation. SOLUTION: When a difference in rotation is generated between output discs 3, rollers 6 roll in pressure contact with the contacting surface 1e of a gear case 1 and the contacting surface 3a of each output disc 3, and in following-up after their movement a cage 6a also rotates. At this time, the rollers 6 are willing to roll in the direction inclined at a certain angle to the rotating track of the output disc, but this is restricted by the cage 6a, and they roll along the rotating track of the output disc 3, so that a friction force is generated between each roller 6 and the contacting surfaces 1e and 3a, and the differential motion is restricted with this friction force working as a resistance. Therein the rollers 6 generate slip friction while they are rolling, so that no static friction is generated but a stable friction force due to dynamic friction is obtained at all times.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a differential device which allows a difference in rotation between left and right or front and rear drive wheels of an automobile.

[0002]

2. Description of the Related Art Conventionally, as a differential device of an automobile, a pinion gear is interposed between a pair of bevel gears connected to an output shaft, and when a rotational force is applied to the shaft of the pinion gear from the outside, the pinion gear rotates upon differential. In general, a rotation difference between the output shafts is allowed. Also, as a differential device with a differential limiting function that restricts one of the drive wheels from trying to idle when turning or traveling on a road surface with a low friction coefficient, a multi-plate clutch is arranged on the back side of the bevel gear, 2. Description of the Related Art There is known an apparatus in which a thrust force of a bevel gear presses a multi-plate clutch to generate a frictional force, thereby transmitting a driving force.

[0003]

However, with a mechanism for transmitting power using sliding friction, such as the above-mentioned multi-plate clutch, it is extremely difficult to regulate the frictional force in a semi-connected state to a constant level. Particularly at low speed rotation, there is a problem that so-called stick-slip occurs in which the clutch plates intermittently generate static friction and dynamic friction, and the differential limiting force becomes extremely unstable. Further, when the frictional force becomes unstable due to stick-slip, noise and vibration are generated, which has a problem of adversely affecting running performance.

[0004] The present invention has been made in view of the above problems, and an object of the present invention is to provide a differential device which can always obtain a stable differential limiting force even at low speed rotation. .

[0005]

In order to achieve the above object, according to the present invention, an input-side rotator that rotates about an axis by a driving force input from the outside, A pair of output-side rotators disposed on the rotation shaft, and a differential transmission mechanism that transmits the rotational force of the input-side rotator to each output-side rotator while allowing a rotation difference between the output-side rotators. In the differential device, when each output-side rotator generates a rotational difference between the input-side rotator and at least one output-side rotator in the axial direction, each of the input-side rotator and the output-side rotator A plurality of rollers that roll while contacting the opposing surface, and each roller is rotatably held at a predetermined distance from each other along a predetermined circumference centered on the rotation axis of the input-side and output-side rotating bodies. A roller holder is provided, and the rolling axis of each roller is rotated on the input side and output side. A first rotating body and a second rotating body which are inclined with respect to a plane including a rotation axis of the body so as to form a predetermined angle, and at least one of the output-side rotating bodies is axially opposed to each other; A large number of concave portions and convex portions engaging with each other are provided on the opposing surface of the second rotating body so as to be in contact with each other at a predetermined inclination angle with respect to the direction in which the rotational force acts. Thus, when the input-side rotator is rotated around the axis by an external driving force, this rotative force is transmitted to each output-side rotator via the differential transmission mechanism. Here, if a rotation difference occurs between the output-side rotators, the rotation difference is allowed by the differential transmission mechanism, and the differential between the output-side rotators is achieved. Further, when the torque fluctuates between the respective output-side rotating bodies, one of the first and second rotating bodies constituting the output-side rotating body attempts to transmit the torque to the other, but the first and second rotating bodies constitute the first and second rotating bodies. Since the concave and convex portions of the rotating body are in contact with each other at a predetermined inclination angle with respect to the direction in which the rotating force acts, an axial reaction force is generated between the first rotating body and the second rotating body. At this time, due to the reaction force of the first and second rotating bodies, each roller rolls while pressing against each opposing surface of the input side and output side rotating bodies,
Each roller moves along the rotation trajectory of each output-side rotator while being restricted by the holder from trying to roll in a direction inclined by a predetermined angle with respect to the rotation trajectory of each output-side rotator. A frictional force is generated between the roller and its contact surface,
This acts as a resistor, limiting the differential. In this case, since each roller generates sliding friction while rolling, a stable friction force due to dynamic friction is always obtained without generating static friction.

According to a second aspect of the present invention, in the differential according to the first aspect, there is provided a biasing means for applying an axial preload to the first and second rotating bodies. Thereby, in addition to the operation of the first aspect, since the first and second rotating bodies are pre-loaded in the axial direction, each roller is pressed in addition to the reaction force of the first and second rotating bodies. Power increases.

According to a third aspect of the present invention, in the differential device according to the first or second aspect, when a rotation difference between the output-side rotating bodies occurs in one rotation direction, the rolling shaft of each roller, the input side, and the input shaft. The angle between the output side rotator and the plane including the rotation axis, and when each output side rotator produces a rotation difference in the other rotation direction, the rolling axis of each roller is the rotation axis of the input side and output side rotator. The rollers are provided so as to be tiltable so that the angles formed with respect to the plane including the above are different from each other. Accordingly, in addition to the operation of the first or second aspect, if the rotation direction of each output side rotating body is different, the inclination angle of each roller changes, and a different magnitude of frictional force is generated. When the rotational difference of the body occurs in one rotational direction, the differential limiting force is large, and when the rotational difference occurs in the other rotational direction, the differential limiting force is small.

[0008]

1 to 8 show one embodiment of the present invention. FIG. 1 is a side sectional view of a differential device, and FIG. 2 is a sectional view taken along line AA of FIG. 3, FIG. 3 is a sectional view taken along the line BB in FIG. 1, FIG. 4 is an exploded perspective view of the differential device, FIGS. 5 and 6 are enlarged views of main parts thereof, and FIGS. It is.

This differential gear includes a gear case 1 forming an input-side rotator, a pair of gear disks 2 forming a first rotator of an output-side rotator, and a pair of gear disks 2 forming a second rotator of an output-side rotator. An output disk 3 and a pair of springs 4 for applying an axial preload to each gear disk 2 and each output disk 3
And two pinion gears 5 for transmitting the rotational force of the gear case 1 to each gear disk 2, and a number of rollers 6 arranged between each output disk 3 and the gear case 1.

The gear case 1 is formed of an integrally molded product having an open side surface, and bearings 1a for supporting the respective output disks 3 are provided at both ends. A flange 1b is provided around the gear case 1, and the flange 1b is provided with a number of holes 1c for bolt insertion. A hole 1d is provided in a side surface of the gear case 1, and each component is accommodated in the gear case 1 through the hole 1d. Further, a contact surface 1e with each roller 6 is formed on an axially opposed surface in the gear case 1 respectively.

Each gear disc 2 has one end face opposed to one end face of each output disc 3, and a bevel gear 2a formed on the other end face. A large number of radially extending recesses 2b are provided at one end face of each gear disc 2 at equal intervals in the circumferential direction, and each recess 2b is formed of a flat bottom surface and slopes on both sides inclined at a predetermined angle. ing.

Each output disc 3 has one end face facing one end face of each gear disc 2 and a contact face 3a with each roller 6 on the other end side. A large number of radially extending projections 3b are provided on one end face of each output disk 3 at equal intervals in the circumferential direction, and each projection 3b is formed from a flat top and two inclined surfaces inclined at a predetermined angle. Is formed. That is, the respective convex portions 3b of the respective output disks 3 and the respective concave portions 2b of the respective gear disks 2 are engaged with each other, and the respective inclined surfaces are in contact with each other. The other end of each output disk 3 is provided with a connecting portion 3c for connection with each drive shaft 7 on the wheel side, and the connecting portion 3c is inserted into one bearing 1a of the gear case 1.

Each spring 4 is wound around a central portion of each output disk 3, and each gear disk 2 and each output disk 3
And is interposed in a compressed state.

Each of the pinion gears 5 has a pinion shaft 5a.
, And are rotatably supported by the bevel gears 2a of the respective gear disks 2. Pinion shaft 5a
Is a pinion block 5 interposed between the pinion gears 5
b, and the pinion block 5b is fixed to the pinion shaft 5a by a pin 5c. The pinion shaft 5a is fixed to a hole 1f provided in the gear case 1 via a washer 5d so as to rotate integrally with the gear case 1. That is, each pinion gear 5 and the pinion shaft 5a constitute a differential transmission mechanism,
The rotation of each pinion gear 5 causes each gear disk 2 to rotate in the opposite direction. A thrust washer 5e is interposed between the pinion block 5b and each gear disk 2.

Each roller 6 has a cylindrical shape extending uniformly in the axial direction, and is held at regular intervals in the circumferential direction by an annular cage 6a as a roller holder. Cage 6a
Has a large number of holes 6b for rotatably accommodating each roller 6, and each hole 6b has a rolling axis X of each roller 6 as shown in FIG.
Is provided so as to be inclined by an angle θ with respect to a plane including the rotation axis of the apparatus main body, that is, a straight line Y extending from the rotation center of the apparatus main body. That is, the rollers 6 roll while contacting the gear case 1 and the contact surfaces 1e and 3a of the output disks 3 while being held by the cage 6a.

In the differential constructed as described above, a ring gear (not shown) connected to the engine side is attached to the flange 1b of the gear case 1, and the gear case 1 is rotated around the axis by the driving force from the engine. It is designed to rotate.

Here, the operation of the differential device is described as follows: when there is no rotation difference between the drive shafts 7, when there is a rotation difference between the drive shafts 7, and only one of the drive shafts 7 idles. Each of the cases in which the state is easily changed will be described.

First, when there is no rotation difference between the drive shafts 7 such as when the vehicle is traveling straight on a road surface having a sufficient frictional force, when the gear case 1 is rotated by the driving force, a pinion is formed integrally with the gear case 1. The shaft 5a rotates, and this rotational force is transmitted to each gear disk 2 via each pinion gear 5. In this case, since there is no rotation difference between the drive shafts 7, the pinion gears 5 do not rotate. Further, the rotational force transmitted to each gear disk 2 is transmitted from each concave portion 2b to each convex portion 3b of each output disk 3.

Next, when a difference in rotation occurs between the drive shafts 7 in a state in which the torque is evenly transmitted to the respective drive wheels, such as when the vehicle is turning on a road surface having a sufficient frictional force, the respective pinion gears 5 The rotation is performed, and the differential rotation is achieved by the reverse rotation of each gear disk 2.

When torque fluctuates between the drive shafts 7 such as when one of the drive wheels loses the frictional force with the road surface, one of the gear disks 2 transmits the rotational force to the other. Therefore, a reaction force is generated between each concave portion 2b of each gear disk 2 and each convex portion 3b of each output disk 3, and an axial thrust force F is applied to each output disk 3 as shown in FIG. Occur. As a result, each roller 6 rolls while being pressed against the contact surface 1e of the gear case 1 and the contact surface 3a of the output disk 3, and the cage 6a rotates accordingly. At this time, the rollers 6 are prevented from rolling in a direction inclined by an angle θ with respect to the rotation trajectory of the output disk 3 (a direction indicated by a dashed line) as shown in FIG. 3 rotation orbits (solid line direction)
Roller 6 and each contact surface 1e, 3
a, a frictional force proportional to the thrust force F is generated, which acts as a resistance to limit the differential of each drive shaft 7. In this case, each roller 6 generates sliding friction while rolling, so that static friction causing stick-slip does not occur, and a stable frictional force due to dynamic friction is always obtained. However, the rolling of each roller 6 instantaneously shifts to dynamic friction. Further, since a load due to the preload of each spring 4 is also applied to each roller 6 in addition to the thrust force F, the force pressing each roller 6 increases in addition to the reaction force of each gear disk 2 and each output disk 3. . Further, since the thrust force F is also applied to each thrust washer 5e between the pinion block 5b and the gear disk 2, a differential limiting force due to frictional resistance of each thrust washer 5e is obtained.

As described above, according to the differential of the present embodiment, the rollers 6 are rolled while being pressed against the contact surface 1e of the gear case 1 and the contact surface 3a of the output disk 3 so that each roller 6 The differential limiting force is generated by the sliding friction accompanying the rolling of the motor, so that even at low speed rotation, a stick-slip does not occur, and a stable friction force can always be obtained, and noise and vibration can be reduced. Generation can also be reliably prevented. In this case, each roller 6
If the inclination angle θ is set to an arbitrary value, the magnitude of the frictional force can be changed, so that a differential limiting force suitable for the purpose can be obtained. Further, since the preload in the axial direction is applied to each roller 6 by each spring 4, the force for pressing each roller 6 can be increased,
A stronger differential limiting force can be obtained.

FIGS. 9 and 10 show a modification of the above embodiment, in which each roller 6 is provided to be tiltable. That is, the cage 6c shown in the figure has a large number of holes 6d for rotatably accommodating each roller 6, and each hole 6d is
Are formed in a fan shape with one end as a base point, and both sides extending from the base point are inclined so as to form mutually different angles with respect to a plane including the rotation axis of the apparatus main body.

With this configuration, when a rotation difference between the drive shafts 7 occurs in one rotation direction, each roller 6 rolls in a state inclined to one end of the cage 6c as shown in FIG. When the rotation difference of each drive shaft 7 occurs in the other rotation direction, each roller 6 rolls in a state inclined to the other end of the cage 6c as shown in FIG. At this time, since the inclination angle of each roller 6 differs depending on the rotation direction, different frictional forces are generated according to the respective inclination angles. Therefore, when the differential of each drive shaft 7 occurs in one rotational direction, the differential limiting force can be increased, and when the differential occurs in the other rotational direction, the differential limiting force can be reduced.

[0024]

As described above, according to the differential device of the first aspect, a frictional force that does not cause stick-slip even at a low speed rotation can be generated, so that the differential limiting is always stable. A force can be obtained, and the generation of noise and vibration can be reliably prevented. Further, since the magnitude of the frictional force can be changed by setting the inclination angle of each roller to an arbitrary magnitude, it is possible to obtain a differential limiting force according to the purpose.

According to the differential device of the second aspect, in addition to the effect of the first aspect, the force for pressing each roller can be increased, so that a stronger differential limiting force can be obtained. .

According to the differential device of the third aspect, in addition to the effects of the first or second aspect, when the rotation difference between the output side rotating bodies occurs in one rotation direction, the differential limiting force is increased, Since it can be reduced when it occurs in the other rotational direction, it is advantageous when it is desired to change the distribution of the driving force to the front wheels and the rear wheels, for example, in a differential device between the front and rear drive wheels of a four-wheel drive vehicle.

[Brief description of the drawings]

FIG. 1 is a side sectional view of a differential device according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG. 1;

FIG. 3 is a sectional view taken along line BB of FIG. 1;

FIG. 4 is an exploded perspective view of the differential device.

FIG. 5 is an enlarged view of a main part of the differential device.

FIG. 6 is an enlarged view of a main part of the differential device.

FIG. 7 is an operation explanatory view showing the principle of generation of frictional force.

FIG. 8 is an operation explanatory diagram showing a principle of generation of a frictional force;

FIG. 9 is a front view of a main part showing a modification.

FIG. 10 is a diagram illustrating the operation of a roller.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Gear case, 2 ... Gear disk, 2b ... Concave part, 3 ...
Output disk, 3b convex portion, 4 spring, 5 pinion gear, 6 roller, 6a, 6c cage.

Claims (3)

[Claims] 1. An input-side rotator that rotates around an axis by a driving force input from the outside, a pair of output-side rotators disposed on a rotation axis of the input-side rotator, and each output-side rotator. And a differential transmission mechanism that transmits the rotational force of the input-side rotator to each output-side rotator while allowing the rotation difference of the input-side rotator and at least one of the output-side rotators. A plurality of rollers that roll while contacting the respective opposing surfaces of the input side and the output side rotator when each output side rotator makes a rotation difference between the opposing surfaces in the axial direction of the A roller holder that is rotatably held at a predetermined interval along a predetermined circumference centered on the rotation axis of the output side rotator, and the rotation axis of each roller is rotated on the input side and the output side. Incline at a given angle to the plane containing the axis of rotation of the body In both cases, at least one of the output-side rotators is composed of a first rotator and a second rotator that are axially opposed to each other, and a large number of recesses and protrusions that engage with each other are provided on opposing surfaces of the first and second rotators. A differential device characterized in that the parts are provided so as to be in contact with each other at a predetermined inclination angle with respect to the direction in which the rotational force acts. 2. The apparatus according to claim 1, further comprising an urging means for applying an axial preload to said first and second rotating bodies.
The differential as described. 3. An angle between a rolling axis of each roller and a plane including rotation axes of the input-side and output-side rotators when a rotation difference between the output-side rotators occurs in one rotation direction; When the output-side rotator makes a rotation difference in the other rotation direction, each roller is formed so that the rolling axis of each roller has a different angle from the plane including the rotation axes of the input-side and output-side rotators. 3. The differential device according to claim 1, wherein the differential device is provided to be tiltable.