JPH11241761A - Ball transmission type differential limiting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ball transmission type differential limiting device which can transmit power in such a way to gradually increase according to a difference of rotational speed. SOLUTION: When a rotational difference is generated between differential gear call and a ball disk 3, each ball 4 reciprocates in a groove of the differential gear case while rolling along a groove of the ball disk 3. When the rotational speed difference between differential gear case and the ball disk 3 become larger, resistance caused when each ball 4 rolls against a viscous fluid is increased, so that power is transmitted between differential case and the ball disk 3. In this case, since the resistance of the viscous fluid increases with a moving speed of each ball 4, power to be transmitted gradually increases according to the rotational difference. A thrust washer, a part of the device, is made of alloy steel or a sintered material which are processed a surface treating such as carboized hardening, nitrided hardening, carbonitrizing hardening, and hard chrome plating or synthetics resin coating.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a differential device mainly used in a drive system of an automobile, and more particularly to a ball transmission type differential limiting device having a differential limiting function.

[0002]

2. Description of the Related Art Conventionally, a differential device used in a driving force transmission system of a vehicle allows a difference in rotation between left and right drive wheels when the vehicle runs on a curve or a difference in rotation between front and rear drive wheels in a four-wheel drive vehicle. If one of the driving wheels runs on a road surface with extremely low coefficient of friction, such as snow or sand, the wheels will spin and lose the entire driving force, making it impossible to escape from the place. It was easy to fall. In addition, when traveling at high speed on a curve, even if the load on the inner wheels is extremely reduced due to centrifugal force, there is also a problem that the wheels idle and the driving force is easily lost.

In order to compensate for such a problem, there has conventionally been provided a device having a function of limiting a differential, and a device using a viscous coupling as a differential limiting mechanism is known. In this case, the viscous coupling is provided in a drive system including the differential device, or is incorporated in the differential device itself.

[0004] A viscous coupling is a kind of rotary transmission mechanism for transmitting torque by using the shear resistance of a viscous fluid (such as silicon oil), and can transmit power by a difference in rotational speed between an input side and an output side. . In other words, if a pair of drive shafts that generate a difference from each other are connected via a viscous coupling, when the rotation speed of one drive shaft increases, the driving force is transmitted to the other drive shaft by the resistance of the viscous fluid. .

[0005]

However, in a differential limiting mechanism utilizing only the shear resistance of a viscous fluid, such as a viscous coupling, a rapid differential limiting effect can be obtained with respect to the rotational speed difference of each drive wheel. When it is combined with a device that works effectively under conditions where each wheel is not restrained by each other, such as a four-wheel antilock brake, the differential limiting effect depends on the rotational speed difference. Ideally, it should gradually increase. Therefore, there is a problem that it is not suitable for combination with a differential limiting mechanism using a viscous coupling. In some cases, the gears bite the gear case while these differentials are moving, and metal powder and metal pieces get into the gears and generate abnormal noises. In some cases, it is necessary to disassemble the device and clean the inside of the device.

The configuration of the ball transmission type differential limiting device according to the present invention will be described later in detail with reference to FIGS. 1 to 13. In this ball transmission type differential limiting device, the difference between the differential case and the ball disk will be described. When the rotation difference occurs, each ball reciprocates in the groove of the differential case while rolling along the groove of the ball disk. At that time, if the difference between the rotational speeds of the differential case and the ball disk increases, the resistance when each ball rolls against the viscous fluid increases, and power is transmitted between the differential case and the ball disk. in this case,
Since the resistance of the viscous fluid increases with the moving speed of each ball, the transmitted power gradually increases according to the rotational speed difference. Even when the material of the thrust washer, which is a component of this device, is made of abrasion-resistant material such as alloy steel (for example, SCM steel) or a sintered material, the abrasion of the thrust washer has been a problem.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to select an appropriate material for each component, and in particular, to improve abrasion resistance by applying a surface treatment to a thrust washer, thereby improving rotation. It is an object of the present invention to provide a ball transmission type differential limiting device capable of exhibiting a differential limiting effect that gradually increases in accordance with a speed difference.

[0008]

In order to achieve the above object, according to the present invention, a pair of a differential case and a ball disk, which are coaxially arranged with their peripheral surfaces radially opposed to each other, are provided. And a plurality of balls disposed between the peripheral surfaces of the ball disk, and a thrust washer interposed between both end surfaces of the ball disk and the differential case and the differential case cover, and the peripheral surface of the differential case has A plurality of guide portions extending linearly in the axial direction are provided, each ball is movably engaged with each guide portion, and a groove for engaging each ball is continuously formed in the circumferential surface of the ball disc in the circumferential direction. Each groove is formed so that when a rotation difference occurs between the differential case and the ball disk, each ball reciprocates along the guide portion, and a space in which each ball moves is filled with a viscous fluid. A Le transmission type differential limiting device, constitute a ball transmission type differential limiting device, characterized in that the thrust washer is made of alloy steel or sintered material was subjected to a surface treatment.

According to the ball transmission type differential limiting device of the first invention, when a rotation difference occurs between the differential case and the ball disk, each ball rolls along the groove of the ball disk. Reciprocate the guide of the differential case. At this time, when the difference in rotational speed between the differential case and the ball disk increases, the resistance when each ball rolls against the viscous fluid increases, and power is transmitted between the differential case and the ball disk. . In this case, since the resistance of the viscous fluid increases with the moving speed of each ball, the transmitted power gradually increases in accordance with the difference in rotational speed.

In the ball transmission type differential limiting device according to the present invention, a gap through which a viscous fluid can flow is formed between at least one of the guide portion and the groove and the ball.

According to the ball transmission type differential limiting device having such a structure, when each ball rolls, the viscous fluid flows through the gap between at least one of the guide portion and the groove. The flow resistance also acts as a power transmitting force.

Further, in the ball transmission type differential limiting device according to the second invention, a differential case which rotates around an axis by a driving force inputted from the outside, and a peripheral surface which is radially arranged on a rotation axis of the differential case. A ball disk and a housing gear coaxially disposed opposite to each other, and a pinion gear and a pinion shaft that transmit the rotational force of the differential case to the housing gear and the side gear while allowing a rotation difference between the housing gear and the side gear. A differential transmission mechanism configured, a plurality of balls disposed between the ball disk and the peripheral surface of the housing gear, between one end surface of the ball disk and the housing cover, the other end surface of the ball disk, and Between the housing gear,
A thrust washer interposed between the housing cover and the gear case cover, and a thrust washer interposed between an end surface of a side gear and the differential case, and a shaft is provided on a peripheral surface of the housing gear. A plurality of guide portions extending linearly in the direction are provided, each ball is movably engaged with each guide portion, and a groove for engaging each ball is continuously provided in the circumferential surface of the ball disc in the circumferential direction. Each groove is formed so that when a rotation difference occurs between the ball disk and the housing gear, each ball reciprocates along the guide portion, and a space in which each ball moves is filled with a viscous fluid in a ball transmission type. A ball transmission type differential limiting device, wherein the thrust washer is made of a surface-treated alloy steel or a sintered material.

According to the ball transmission type differential limiting device of the second invention, when the differential case is rotated around the axis by an external driving force, the rotational force is transmitted to the housing gear and the housing gear via a differential transmission mechanism. It is transmitted to the side gear. Here, when a rotation difference occurs between the housing gear and the side gear, the rotation difference is allowed by a differential transmission mechanism,
A differential between the ball disc and the housing gear is achieved. At this time, since each ball reciprocates in the guide portion of the housing gear while rolling along the groove of the ball disc, when the rotational speed difference between the ball disc and the housing gear increases, each ball becomes viscous. The resistance when rolling against the fluid increases, and the differential between the ball disc and the housing gear is limited. In this case, since the resistance of the viscous fluid increases with the moving speed of each ball, the differential limiting effect is generated so as to gradually increase according to the rotation speed difference.

According to the third aspect of the present invention, a differential case that rotates around an axis by a driving force input from the outside, a pair of side gears disposed on a rotation shaft of the differential case, and a rotational difference between the side gears are determined. A differential transmission mechanism composed of a pinion gear and a pinion shaft for transmitting the rotational force of the differential case to the side gears while allowing the differential case is disposed between the peripheral surface of the ball disk and the peripheral surface of the differential case opposed thereto. A plurality of balls, between the end face of one of the side gears and the other differential case,
A thrust washer interposed between the end face of the other side gear and the one differential case,
A plurality of guide portions extending linearly in the axial direction are provided on one peripheral surface of the differential case, and each ball is movably engaged with each guide portion, and each ball is engaged with the peripheral surface of the ball disc. Grooves are formed continuously in the circumferential direction, and each groove is formed so that when a rotation difference occurs between the differential case and the ball disk, each ball reciprocates along the guide portion, and is formed in a space where each ball moves. Is a ball transmission type differential limiting device filled with a viscous fluid, wherein the thrust washer is made of a surface-treated alloy steel or a sintered material to constitute a ball transmitting type differential limiting device. I have.

Further, according to the ball transmission type differential limiting device of the third invention, when the differential case is rotated around the axis by the driving force from the outside, the rotational force is transmitted to each side gear via the differential transmission mechanism. Is transmitted. Here, when a rotation difference occurs in each side gear, the rotation difference is allowed by the differential transmission mechanism, and the differential between the differential case and the ball disk is achieved. At this time, since each ball reciprocates along the other guide portion while rolling along one groove of the ball disc and the differential case, when the rotational speed difference between the differential case and the ball disk increases, each ball Increases when rolling against the viscous fluid,
The differential between the differential case and the ball disk is limited. In this case, since the resistance of the viscous fluid increases with the moving speed of each transfer body, the differential limiting effect is generated so as to gradually increase in accordance with the rotation speed difference.

In the ball transmission type differential limiting device according to the present invention, a gap through which a viscous fluid can flow is formed between at least one of the guide portion and the groove and the ball.

Further, in the ball transmission type differential limiting device according to the present invention, the surface treatment of the thrust washer is carburizing hardening, nitriding hardening, carbonitriding hardening, or hard chromium plating. Make up the limiting device.

Further, in the ball transmission type differential limiting device according to the present invention, the material of the thrust washer is alloy steel, and the surface treatment is a synthetic resin coating. Is composed.

[0019]

According to the ball transmission type differential limiting device of the present invention, when a rotation difference occurs between the differential case and the ball disk, each ball rolls along the groove of the ball disk while the differential case rotates. Reciprocate in the groove of. At this time, if the difference in rotational speed between the differential case and the ball disk increases, the resistance when each ball rolls against the viscous fluid increases, and power is transmitted between the differential case and the ball disk. In this case, since the resistance of the viscous fluid increases with the moving speed of each ball, the transmitted power gradually increases in accordance with the difference in rotational speed. Parts other than the thrust washer which are parts of this device, such as a differential case and a housing gear, are made of spheroidal graphite cast iron, and a ball disc is made of austempered spheroidal graphite cast iron (shot peening on the surface to improve fatigue strength). Or martensitic base spheroidal graphite cast iron, alloy steel, or the like, and the ball holder may be alloy steel, precision cast product, or the like.

The thrust washer must be made of a material that does not bite the inner surface of the differential case and that has excellent wear resistance. An alloy steel such as SCM steel or a sintered material is subjected to a surface treatment to impart wear resistance. As the surface treatment, carburizing hardening, nitriding hardening, carbonitriding hardening, hard chrome plating, or synthetic resin coating is applied. Here, only synthetic resin coating is applied to alloy steel in consideration of technical aspects and its effects, and is not applied to sintered materials.

The above-mentioned surface treatment for the thrust washer includes:
State-of-the-art technology can be applied. That is, the carburizing hardening treatment is performed by mixing the thrust washer and the carburizing agent in a sealed container for 850 minutes.
Carburize by heating to ~ 900 ° C. About 830-90 to refine and refine the grains coarsened by carburization.
After oil quenching (primary quenching) from 0 ° C,
Heat to 800 ° C. to quench water or oil. In addition,
It is preferable to perform tempering to remove strain. In addition to such solid carburization, a gas carburization method may be applied.

In the nitriding hardening treatment, when nitriding hardening with NH ₃ gas, the content of Cr for increasing the depth of nitriding and the content of Mo for preventing temper brittleness are taken into consideration.
It is preferable to select an appropriate alloy steel. Further, as the carbonitriding treatment, either a liquid carbonitriding method or a gas carbonitriding method may be applied.

The hard chromium plating treatment includes C
A hard chromium layer (approximately 5 μm) can be formed on the surface by immersing in an electrolytic solution and plating. As the synthetic resin coating treatment, phenol resin paper phenol is adhered to the surface. By performing the above-described processing, the thrust washer can be given wear resistance.

FIGS. 1 to 5 show a first embodiment of the present invention.
FIG. 1 is a side sectional view of a ball transmission type differential limiting device, FIG. 2 is a sectional view taken along line AA of FIG. 1, and FIG. 3 is a sectional view taken along line BB of FIG. FIG. 1 is a view of FIG.
FIG. 5 is an exploded perspective view of the ball transmission type differential limiter as seen from the direction of the line C.

This ball transmission type differential limiting device includes a differential case 1, a differential case cover 2 for closing one end of the differential case 1, a ball disk 3 arranged coaxially with the differential case 1, and a differential case 1 and a ball disk 3 of the differential case 1. A large number of balls 4 arranged between the peripheral surfaces,
The space in which each ball 4 moves is filled with a viscous fluid 5. That is, the differential case 1 constitutes one rotating body, the ball disk constitutes the other rotating body, and each ball 4 constitutes a rolling element.

The differential case 1 has a cylindrical shape with one end opened, and a bearing 1a for supporting one end of the ball disk 3 is provided at the center of the other end. A number of grooves 1b with which each ball 4 engages are provided on the inner peripheral surface of the differential case 1, and each groove 1b extends linearly in the axial direction and is provided at regular intervals in the circumferential direction. That is, each groove 1b forms a guide. In each groove 1b, there is provided a fluid passage 1c that forms a gap between the ball 4 and the fluid passage 1c. The viscous fluid 5 can flow through the fluid passage 1c.

The differential case cover 2 is formed in a disk shape, and a bearing 2a for supporting the other end of the ball disk 3 is provided at the center thereof, and is joined to the differential case 1 by welding. A connecting portion 2b connected to one drive system (not shown) is provided on the outer surface side of the differential case cover 2, and a spline is formed on a peripheral surface of the connecting portion 2b. The differential case cover 2 has a filling hole 2c for filling the viscous fluid 5 in the differential case 1, and the filling hole 2c
Is closed by the ball 2d after the viscous fluid 5 is filled,
The ball 2d is fixed by crushing the periphery of the filling hole 2c. In this case, the filling holes 2c are provided at a total of two or more places for injection and air release. Further, an annular groove 2e for dispersing the injected viscous fluid 5 in the circumferential direction inside the differential case 1 is provided on the inner surface side of the differential case cover 2, and the groove 2e is formed so as to communicate with each filling hole 2c. ing.

The ball disk 3 has a shaft 3a extending in the axial direction, and the other drive system (not shown) is connected to the shaft 3a. The shaft 3a side of the ball disk 3 is supported by a bearing 1a of the differential case 1 via a bearing 6, and the bearing 6 is fixed to the differential case 1 by a pair of C rings 6a, 6b. A large number of grooves 3b with which each ball 4 engages are provided on the peripheral surface of the ball disc 3, and each groove 3b extends continuously in the circumferential direction, and each ball 4 reciprocates along the groove 1b of the differential case 1. It is formed in a meandering shape so that In each groove 3b, there is provided a fluid passage 3c that forms a gap between the groove 3b and the ball 4, and the viscous fluid 5 can flow through the fluid passage 3c. A plurality of fluid passages 3 communicating the groove 3 b and one end surface of the ball disk 3 are formed on the peripheral surface of the ball disk 3.
The viscous fluid 5 injected from the filling hole 2c of the differential case cover 2 is filled in the groove 3b through the fluid passage 3d. Furthermore, the ball disk 3
A thrust washer 3e is interposed between the differential case 1 and the differential case 1 and the differential case cover 2. An oil seal 3f is interposed between the ball disk 3 and the differential case 1 and between the ball disk 3 and the differential case cover 2, respectively.

Each ball 4 is arranged in the circumferential direction of the ball disk 3 and is rotatably engaged with the groove 1b of the differential case 1 and the groove 3b of the ball disk 3, respectively. Each ball 4
Are rotatably held by a large number of ball holders 4a formed in a plate shape, and each ball holder 4a is provided with a hole 4b for accommodating each ball 4 one by one. Each ball holder 4a is slidably interposed between the differential case 1 and the ball disk 3, and a spacer 4c is provided between each ball holder 4a.

The viscous fluid 5 is made of silicon oil or the like,
The space enclosed by the differential case 1, the differential case cover 2, and the ball disk 3 is filled.

In the ball transmission type differential limiting device configured as described above, the differential case 1 and the ball disc 3
When a rotation difference occurs between the balls 4, the balls 4 roll along the grooves 3 b of the ball disc 3 while
Reciprocate in b. At this time, if the difference in the rotation speed between the differential case 1 and the ball disk 3 increases, the resistance when each ball 4 rolls against the viscous fluid 5 increases, and the power between the differential case 1 and the ball disk 3 increases. Is transmitted.
In this case, since the resistance of the viscous fluid 5 increases with the moving speed of each ball 4, the transmitted power gradually increases in accordance with the difference in rotational speed. In addition, each ball holder 4
When each ball 4 rolls in each of the grooves 1b, 3b sealed by a, a viscous fluid 5 flows into the fluid passages 1
Since c and 3c flow, the flow resistance at that time also acts as a force for transmitting power.

For example, when a front wheel and a rear wheel of an automobile are connected via the ball transmission type differential limiting device of the first embodiment of the present invention, when the driving wheel on the driving side idles, the driving side Torque can be transmitted to the drive wheels. That is, assuming that the ball disc 3 side is connected to the driving shaft on the driving side and the differential case 1 side is connected to the driving shaft on the driven side.
In normal traveling, the differential case 1 and the ball disk 3 rotate independently of each other at substantially the same rotational speed.
Next, when the driving wheel on the driving side slips and idles, the rotational speed difference between the differential case 1 and the ball disk 3 increases, and the power of the ball disk 3 is transmitted to the differential case 1 side by the resistance of the viscous fluid 5.

As described above, according to the ball transmission type differential limiting device of the first embodiment of the present invention, the differential case 1 is formed by the resistance when each ball 4 rolls against the viscous fluid 5. Since the power is transmitted between the motor and the ball disc 3, the power can be transmitted so that the power gradually increases in accordance with the rotational speed difference. Therefore, for example, when used as a rotation-sensitive differential limiting mechanism in a drive system of an automobile, an accurate differential limiting effect according to a rotational speed difference can always be obtained, and a mechanism for transmitting power by a rotational speed difference can be obtained. It can be effectively used for other necessary devices.
Further, the viscous fluid 5 is applied to each groove 1 as the balls 4 roll.
Since the fluid flows through the fluid passages 1c and 3c of b and 3b, resistance for transmitting power can be reliably generated.

FIGS. 6 to 9 show a second embodiment of the present invention.
6 is a side sectional view of the ball transmission type differential limiting device, FIG. 7 is a sectional view taken along the line AA in FIG. 6, and FIGS. 8 and 9 are ball transmitting type differential limiting devices. It is an exploded perspective view of a device. Note that the dashed lines in FIGS. 8 and 9 indicate that they are continuous with the same numbers corresponding to the respective figures.

This ball transmission type differential limiting device comprises a differential case 10, a differential case cover 11 for closing one end of the differential case 10, a pair of drive shafts 12, 13 arranged coaxially with each other, and one drive shaft 1
2 and the ball disc 1 which also rotates integrally with one drive shaft 12.
5, a housing gear 16 that rotates integrally with the other drive shaft 13, a number of balls 17 disposed between the ball disc 15 and the peripheral surfaces of the housing gear 16, a side gear 14 and the housing gear 16, and a differential case 10.
And a total of four pinion gears 18 that transmit the rotational force of the differential case 10 while allowing the rotational difference.
Is filled with a viscous fluid 19. That is, the differential case 10 uses the input-side rotating body as one of the drive shaft 12, the side gear 14, and the ball disc 15.
Represents one output side rotating body and the other drive shaft 13
The housing gear 16 constitutes the other output-side rotating body, and each ball 17 constitutes a rolling element.

The differential case 10 has a cylindrical shape with one end opened, and a bearing 10a for supporting one drive shaft 12 is provided at the center. A flange 10b is provided around the differential case 10, and the flange 10b is provided with a large number of holes 10c for bolt insertion. A groove 10d for supporting each pinion gear 18 is provided on the inner peripheral surface of the differential case 10.

The differential case cover 11 is formed in a disk shape, and a bearing 11a for supporting the other drive shaft 13 is provided at the center. Differential case cover 1
1 is provided with a flange 11b on the periphery thereof.
b has a number of holes 11c for bolt insertion. That is, the differential case cover 11 includes the flanges 10b,
11b by a bolt 11d for fastening the differential case 10b.
Assembled in

Each of the drive shafts 12 and 13 has flanges 12a and 13a for connecting to left and right drive wheels of an automobile, respectively. One drive shaft 12 is formed longer in the axial direction than the other drive shaft 13. . One drive shaft 12 has connecting portions 12b and 12c having a spline structure at a total of two locations on the peripheral surface. The connecting portion 12b on the distal end side is connected to the ball disk 15, and the connecting portion 12c on the central side is connected to the side gear 14. Have been. The other drive shaft 13 has a connecting portion 13 b having a spline structure on a peripheral surface, and the connecting portion 13 b is connected to the housing gear 16.

The side gear 14 is coaxially connected to one of the drive shafts 12, and has a bevel gear 14a formed on a surface facing the housing gear 16. A thrust washer 14b is interposed between the end surface of the side gear 14 and the differential case 10.

The ball disk 15 has a cylindrical portion 15a having a spline structure, and one drive shaft 12 is connected to the cylindrical portion 15a. A large number of grooves 15b are provided on the peripheral surface of the ball disk 15 for engaging the respective balls 17, and each groove 15b extends continuously in the circumferential direction so that each ball 17 reciprocates in the axial direction of the differential case 10. It is formed in a meandering shape. In each groove 15b, there is provided a fluid passage 15c which forms a gap with the ball 17, and a viscous fluid 19 can flow through the fluid passage 15c. Further, a plurality of fluid passages 15d communicating the groove 15b and one end surface of the ball disk 15 are provided on the peripheral surface of the ball disk 15.

The housing gear 16 is formed in a cylindrical shape, and a bevel gear 16a is formed on a surface facing the side gear 14. The ball disc 15 is provided in the housing gear 16.
Is accommodated, and the cylindrical portion 15a of the ball disk 15 passes through the housing gear 16. A number of grooves 16b with which each ball 17 is engaged are provided on the inner peripheral surface of the housing gear 16, and each groove 16b extends linearly in the axial direction and is provided at equal intervals in the circumferential direction. That is, each groove 16b forms a guide. A fluid passage 16c is formed in each groove 16b to form a gap between the groove 16b and the ball 17, and a viscous fluid 19 can flow through the fluid passage 16c. The other end surface of the housing gear 16 is closed by a housing cover 16d, and the other drive shaft 13 is connected to the housing cover 16d.

The housing cover 16d has a filling hole 16e for filling the housing gear 16 with the viscous fluid 19, and the filling hole 16e is closed by the ball 16f after the viscous fluid 19 is filled. To fix the ball 16f. In this case, the filling holes 16e are provided at a total of two places for injection and air vent, and the viscous fluid 19 injected from the filling holes 16e is filled into the grooves 15b through the fluid passages 15d of the ball disk 15. Further, an annular groove 16g for dispersing the injected viscous fluid 19 in the circumferential direction in the housing gear 16 is provided on the inner surface side of the housing cover 16d, and the groove 16g is formed so as to communicate with each filling hole 16e. Have been. A thrust washer 16h is interposed between one end surface of the ball disk 15 and the housing cover 16d, between the other end surface of the ball disk 15 and the housing gear 16, and between the housing cover 16d and the differential case cover 11, respectively. An oil seal 16i is interposed between the ball disk 15 and the housing gear 16 and between the ball disk 15 and the housing cover 16d.

Each ball 17 is arranged in the circumferential direction of the ball disk 15, and each of the balls 17 has a groove 15 b of the ball disk 15.
And the groove 16b of the housing gear 16 so as to roll freely. Each ball 17 is rotatably held by a large number of ball holders 17a formed in a plate shape.
a is provided with a hole 17b for accommodating each ball 17 one by one. Each ball holder 17a is slidably interposed between the ball disk 15 and the housing gear 16, and a spacer 17c is provided between each ball holder 17a.

Each of the pinion gears 17 is rotatably supported by a pinion shaft 18a orthogonal to the support shaft, and is meshed with a bevel gear 14a of the side gear 14 and a bevel gear 16a of the housing gear 16, respectively. The pinion shaft 18a is fixed to the groove 10d of the gear case 10 so as to rotate integrally with the gear case 10. That is, a differential transmission mechanism is constituted by each of the pinion gears 18 and the pinion shaft 18a, and the side gear 14 and the housing gear 16 rotate in opposite directions by the rotation of each of the pinion gears 18.

The viscous fluid 19 is made of silicon oil or the like, and is filled in a space closed by the ball disk 15, the housing gear 16, and the housing cover 16d.

In the ball transmission type differential limiting device configured as described above, the flange 10b of the differential case 10
A ring gear (not shown) for transmitting the driving force from the engine is attached to the motor, and the entire device rotates around the axis of the differential case 10.

Here, the operation of the ball transmission type differential limiting device according to the second embodiment of the present invention will be described based on the case where there is no rotation difference between the drive shafts 12 and 13 and the case where the drive shafts 12 and 13 A description will be given of a case where a rotation difference occurs in the drive shaft 13 and a case where one of the drive shafts 12 and 13 slips easily.

First, when there is no rotation difference between the drive shafts 12 and 13 such as when the vehicle is traveling straight on a road surface having a sufficient frictional force, when the differential case 10 is rotated by the driving force, the differential case 10 The pinion shaft 18a rotates integrally, and the rotation force is applied to each pinion gear 1
2 to the side gear 14 and the housing gear 16. In this case, since there is no rotation difference between the drive shafts 12 and 13, the pinion gears 12 do not rotate. Further, the rotational force transmitted to the housing gear 16 is transmitted to the other drive shaft 13 via the housing cover 16d.

Next, when a difference in rotation occurs between the drive shafts 12 and 13 in a state where the torque is transmitted to the respective drive wheels even when the vehicle is turning on a road surface having a sufficient frictional force, the pinion gear 18 rotates and reverse rotation of the side gear 14 and the housing gear 16 achieves differential.
At this time, the ball disk 15 rotates integrally with one drive shaft 12 and the housing gear 16 rotates integrally with the other drive shaft 13, so that the ball disk 15 and the housing gear 16 rotate in opposite directions. Thus, each ball 17 reciprocates in the groove 16b of the housing gear 16 while rolling along the groove 15b of the ball disk 15.

Next, when one of the drive wheels loses the frictional force with the road surface and idles, for example, the drive shafts 12 and
When the rotational speed difference between the balls 13 increases, the resistance of each ball 17 when rolling against the viscous fluid 19 increases, and this acts as a force for limiting the differential. In this case, since the resistance of the viscous fluid 19 increases with the moving speed of each ball 17, the differential limiting effect is reduced by the drive shaft 12,
The rotation speed gradually increases in accordance with the rotation speed difference between the motors 13. Also,
Each groove 15b sealed by each ball holder 17a,
When each ball 17 rolls inside 16b, the viscous fluid 19 flows through the fluid passages 15c, 16c of the grooves 15b, 16b, and the flow resistance at that time also acts as a force for transmitting power.

As described above, according to the ball transmission type differential limiting device of the second example of the embodiment of the present invention, each ball 17
Is limited by the resistance when rolling against the viscous fluid 19, the differential between the drive shafts 12 and 13 is limited, so that the differential limiting effect is generated such that the differential limiting effect gradually increases in accordance with the rotational speed difference. Can be done. Therefore, since there is no sudden difference limiting effect in the initial stage of the differential operation, the restraint of each drive wheel is reduced, which is extremely advantageous when combined with an antilock brake.

10 to 13 show a third embodiment of the present invention. FIG. 10 is a side sectional view of a ball transmission type differential limiting device, and FIG. 11 is a line AA in FIG. 12 and 13 are exploded perspective views of the ball transmission type differential limiting device. Note that the dashed lines in FIGS. 12 and 13 indicate that they are continuous with the same numbers corresponding to the respective figures.

This ball transmission type differential limiting device comprises a pair of differential cases 20, 21, a differential case cover 22 for closing one end of the other differential case 21, and a pair of drive shafts 23, 24 arranged coaxially with each other. A pair of side gears 25 that rotate integrally with the drive shafts 23 and 24, a ball disk 26 that rotates integrally with the other drive shaft 24, and a number of balls arranged between the ball disk 26 and the peripheral surface of one differential case 20. Ball 2
7 and a total of two pinion gears 28 for transmitting the rotational force of the differential cases 20 and 21 to each side gear 25 while allowing a rotational difference, and each ball 2 in the other differential case 21 is provided.
The space in which 7 moves is filled with a viscous fluid 29.
That is, each differential case 20, 21 is an input side rotating body, one drive shaft 23 and one side gear 25 are one output side rotating body, and the other drive shaft 24, the other side gear 25 and the ball disk 26 are the other. Each ball 27 constitutes an output side rotating body, and each ball 27 constitutes a rolling element.

One differential case 20 has a cylindrical shape with one end opened, and a bearing 20a for supporting one drive shaft 23 is provided at the center thereof. Differential case 2
0, a flange 20b is provided.
b has a number of holes 20c for bolt insertion. The differential case 20 has a hole 20d for supporting each pinion gear 28.

The other differential case 21 has a cylindrical shape with one end opened, and a hole 21a through which the other drive shaft 24 and the hole disk 26 are inserted is provided at the center. A flange 21b is provided around the differential case 21, and the flange 21b has a number of holes 21 for bolt insertion.
c is provided. That is, the differential cases 20, 21 are assembled to each other by the bolts 21d for fastening the flanges 20b, 21b. The inner peripheral surface of the differential case 21 is provided with a number of grooves 21a with which the respective balls 27 are engaged. The grooves 21e extend linearly in the axial direction and are provided at equal intervals in the circumferential direction. That is, each groove 21e forms a guide. In each groove 21e, there is provided a fluid passage 21f which forms a gap with the ball 27, and the viscous fluid 29 can flow through the fluid passage 21f.

The differential case cover 22 is formed in a disk shape, and the other drive shaft 24
Is provided, and is joined to the other differential case 21 by welding. The differential case cover 22 has a filling hole 22b for filling the other differential case 21 with the viscous fluid 29. The filling hole 22b is closed by the ball 22c after the viscous fluid 29 is filled, and the periphery of the filling hole 22b is crushed. By doing so, the ball 22c is fixed. In this case, the filling holes 22b are provided at a total of two places for injection and for venting. Further, an annular groove 22 for dispersing the injected viscous fluid 29 in the circumferential direction inside the differential case 22 is provided on the inner surface side of the differential case cover 22.
d is provided, and the groove 22d is formed so as to communicate with each filling hole 22b.

Each of the drive shafts 23, 24 has flanges 23a, 24a for connection to the left and right drive wheels of the vehicle, respectively, and the other drive shaft 24 is formed longer in the axial direction than one drive shaft 23. . Each of the drive shafts 23 and 24 has splined connecting portions 23b and 24b on its peripheral surface. The connecting portion 23b of one drive shaft 23 is connected to one side gear 25, and the connecting portion 24b of the other drive shaft 24 is The distal end is connected to the other side gear 25, and the central side is connected to the ball disc 26.

Each side gear 25 is connected to each drive shaft 2
Bevel gears 25a are formed coaxially with the gears 3 and 24, and are formed on surfaces facing each other. A thrust washer 25b is interposed between the end surface of one side gear 25 and the other differential case 21, and between the end surface of the other side gear 25 and the one differential case 20, respectively.

The ball disk 26 is the other differential case 2
1 and a splined hole 26a
And the other drive shaft 24 is connected to the hole 26a. A large number of grooves 26b with which each ball 27 is engaged are provided on the peripheral surface of the ball disc 26.
Extend continuously in the circumferential direction, and are formed in a meandering shape so as to reciprocate each ball 27 in the axial direction of the differential case 20, 21. The ball 2 is provided in each groove 26b.
7, a fluid passage 26c that forms a gap between
The viscous fluid 29 can flow through the fluid passage 26c. Further, a plurality of fluid passages 26 d communicating the groove 26 b and one end face of the ball disc 26 are provided on the peripheral surface of the ball disc 26, and the viscous fluid 29 injected from the filling hole 22 b of the differential case cover 22
The groove 26b is filled through 6d. Further, a thrust washer 26e is interposed between one end surface of the ball disk 26 and the differential case cover 22, and an oil seal is provided between the ball disk 26 and the differential case 21 and between the ball disk 26 and the differential case cover 22, respectively. 26f is interposed.

Each ball 27 is arranged in the circumferential direction of the ball disk 26, and the groove 26b
And the other differential case 21 is rotatably engaged with the groove 21e. Each ball 27 is rotatably held by a number of ball holders 27a formed in a plate shape.
7a is provided with a hole 27b for accommodating each ball 27 one by one. Each ball holder 27a is slidably interposed between the ball disk 26 and the differential case 21, and a spacer 27c is provided between each ball holder 27a.

Each pinion gear 28 is rotatably supported by a cylindrical pinion shaft 28a, and is meshed with a bevel gear 25a of each side gear 25. Both ends of the pinion shaft 28a are inserted into the holes 20d of the one differential case 20, and one end of the pinion shaft 28a is fixed to the differential case 20 by a spring pin 28b so as to rotate integrally with the differential case 21. That is, a differential transmission mechanism is constituted by each of the pinion gears 28 and the pinion shaft 28a, and the respective side gears 25 rotate in directions opposite to each other by the rotation of each of the pinion gears 28.

The viscous fluid 29 is made of silicon oil or the like,
The other differential case 21, the differential case cover 22, and the ball disk 26 fill the space enclosed by the space.

In the ball transmission type differential limiting device constructed as described above, when a rotation difference occurs between the drive shafts 23 and 24, the respective pinion gears 28 rotate and the respective side gears 25 reversely rotate to achieve the differential. Is done. that time,
Since the ball disk 26 rotates integrally with the other drive shaft 24, a rotation difference occurs between the ball disk 26 and the other differential case 21. Thus, each pawl 27 reciprocates in the groove 21e of the differential case 21 while rolling along the groove 26b of the pawl disk 26. At this time, when the difference in the rotational speed between the drive shafts 23 and 24 increases, the resistance when each ball 27 rolls against the viscous fluid 29 increases, and this acts as a force that limits the differential. In this case, since the resistance of the viscous fluid 29 increases with the moving speed of each ball 27, the differential limiting effect gradually increases in accordance with the rotational speed difference between the drive shafts 23 and 24. In addition, each ball holder 27a
The inside of each groove 21e, 26b sealed by
When the roller 7 rolls, the viscous fluid 29 flows through the fluid passages 21f and 26c of the grooves 21e and 26b, and the flow resistance at that time also acts as a force for transmitting power.

As described above, according to the ball transmission type differential limiting device of the third embodiment of the present invention, each ball 27 is attached to the viscous fluid 29 similarly to the second embodiment of the above embodiment. Due to the resistance at the time of rolling, the differential limiting effect can be generated so as to gradually increase in accordance with the rotational speed difference between the drive shafts 23 and 24.

Here, the thrust washer 3c is made of alloy steel or sintered material, and is subjected to surface treatment of carburizing hardening, nitriding hardening, carbonitriding hardening, hard chromium plating, synthetic resin coating, and in the case of no surface treatment. The abrasion resistance was evaluated. The evaluation test was conducted with an input torque of 91 N-m and a differential rotation speed of 30 rpm.
The evaluation was performed by observing the sliding surface after the test, under the conditions of m, the number of endurance differentials was 240,000 differentials. Those subjected to carburizing hardening, nitriding hardening, carbonitriding hardening, and hard chromium plating had good abrasion resistance and no galling occurred. The one coated with a synthetic resin had slightly better abrasion resistance, but the one without surface treatment had galling. From these results, it is understood that the abrasion resistance is improved by performing the surface treatment of the present invention.

[0066]

As described above, based on the selection of appropriate materials for the main parts constituting the ball transmission type differential limiting device of the present invention, especially the thrust washer is made of alloy steel or sintered material. By applying a surface hardening treatment to the surface and imparting abrasion resistance, it is possible to obtain power transmission due to a difference in rotation speed, and smooth characteristics in which the transmitted power gradually increases in accordance with the difference in rotation speed. Not only can it be effectively used for a drive system of various machines aiming at such an operation, for example, an automobile, but also its simple structure is very advantageous for cost reduction and miniaturization. When the ball transmission type differential limiting device of the present invention is applied to the drive system of an automobile, the differential limiting effect can be generated so as to gradually increase in accordance with the rotational speed difference, so that it can be accurately determined according to the running conditions. This is extremely advantageous when combined with an anti-lock brake, because the differential can be limited and the driving wheels are less restrained in the initial stage of the differential.

[Brief description of the drawings]

FIG. 1 is a side sectional view of a ball transmission type differential limiting device shown in a first example of an embodiment of the present invention.

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

FIG. 3 is a view as seen from the direction of arrows BB in FIG. 1;

FIG. 4 is a view as seen from the direction of arrows CC in FIG. 1;

FIG. 5 is an exploded perspective view of the ball transmission type differential limiting device.

FIG. 6 is a side sectional view of a ball transmission type differential limiting device shown in a second example of an embodiment of the present invention.

FIG. 7 is a sectional view taken along line AA of FIG. 6;

FIG. 8 is an exploded perspective view of the ball transmission type differential limiting device.

FIG. 9 is an exploded perspective view of the ball transmission type differential limiting device.

FIG. 10 is a side sectional view of a ball transmission type differential limiting device shown in a third example of an embodiment of the present invention.

FIG. 11 is a sectional view taken along line AA of FIG. 10;

FIG. 12 is an exploded perspective view of a ball transmission type differential limiting device.

FIG. 13 is an exploded perspective view of the ball transmission type differential limiting device.

[Explanation of symbols]

1, 10, 20, 21 Differential case 2, 11, 22 Differential case cover 3, 15, 26 Ball disc 4, 17, 27 Ball 5, 19, 29 Viscous fluid 6 Bearing 12, 13, 23, 24 Drive shaft 14, 25 Side gear 16 Housing gear 18, 28 Pinion gear 1a, 2a, 10a, 11a, 20a, 22a Bearing 1b, 21e Grooves 1c, 3c, 3d, 15c, 15d, 16c, 21f provided on the inner peripheral surface of the differential case
26c, 26d Fluid passages 2b, 12b, 12c, 13b, 23b, 24b Connecting parts 2c, 16e, 22b Filling holes 2d, 16f, 22c for filling viscous fluid Balls for sealing viscous fluid filling holes 2e, 16g, 22d Grooves 3a shafts 3b, 15b, 26b grooves 6a, 6b provided on the peripheral surface of the ball disk C-ring 16b grooves 3e, 14b, 16h, 25b, 26e with which balls provided on the inner surface of the housing gear engage. 3f, 16i, 26f Oil seals 4a, 17a, 27a Ball holders 4b, 17b, 27b Ball receiving holes 4c, 27c Spacers 10b, 11b, 12a, 13a, 20b, 21b, 2
3a, 24a Flange 16d Housing cover 10c, 11c, 20c, 21c Bolt insertion hole 11d, 21d Fastening bolt 10d Pinion gear support groove 20d Pinion gear support hole 14a, 16a, 25a Bevel gear 15a Cylindrical portion of ball disk 18a, 28a Pinion shaft 21a Hole for inserting ball disc 28b Spring pin

Claims (10)

[Claims] 1. A pair of a differential case and a ball disk arranged coaxially with their peripheral surfaces radially opposed to each other, a plurality of balls disposed between the peripheral surfaces of the differential case and the ball disk, and the balls A thrust washer interposed between both end surfaces of the disc and the differential case and the differential case cover, and a plurality of guide portions that extend linearly in the axial direction are provided on a peripheral surface of the differential case, and each guide portion has The ball is movably engaged, and grooves for engaging with each ball are continuously provided in the circumferential surface of the ball disk in the circumferential direction. Each groove is formed when a rotation difference occurs between the differential case and the ball disk. Are formed so as to reciprocate along the guide portion, and a space in which each ball moves is a ball transmission type differential limiting device filled with a viscous fluid, wherein the thrust washer has a surface. Ball transmission type differential limiting device characterized by comprising an alloy steel or sintered material was subjected to physical. 2. The ball transmission type differential limiting device according to claim 1, wherein a gap through which a viscous fluid can flow is formed between at least one of the guide portion and the groove and the ball. 3. A differential case which rotates around an axis by a driving force inputted from the outside, a ball disk and a housing gear which are coaxially arranged on a rotational axis of the differential case so that peripheral surfaces thereof are radially opposed to each other. A differential transmission mechanism including a pinion gear and a pinion shaft for transmitting the rotational force of the differential case to the housing gear and the side gear while allowing a rotation difference between the housing gear and the side gear; and the ball disk and the housing. A plurality of balls arranged between the peripheral surfaces of the gears, between one end face of the ball disc and the housing cover, between the other end face of the ball disc and the housing gear, and between the housing cover and the gear case cover. Each thrust washer interposed between the end face of the side gear and the thrust washer A thrust washer interposed between the differential gear and a differential case, and a plurality of guide portions extending linearly in the axial direction are provided on a peripheral surface of the housing gear, and each ball is movably engaged with each guide portion. On the peripheral surface of the ball disk, grooves for engaging with each ball are provided continuously in the circumferential direction, and when a rotation difference occurs between the ball disk and the housing gear, each ball moves along the guide portion. A ball transmission type differential limiting device formed so as to reciprocate and filled with a viscous fluid in a space where each ball moves, wherein the thrust washer is made of a surface-treated alloy steel or sintered material. A ball transmission type differential limiting device characterized by the following. 4. A differential case that rotates around an axis by a driving force input from outside, a pair of side gears disposed on a rotation shaft of the differential case, and a differential gear of the differential case that allows a rotation difference between the side gears. A differential transmission mechanism composed of a pinion gear and a pinion shaft for transmitting a rotational force to each of the side gears; and a plurality of balls arranged between a peripheral surface of a ball disk and a peripheral surface of the differential case opposed thereto. A thrust washer interposed between the end face of the side gear and the other differential case, and between the end face of the other side gear and the one differential case, and a shaft is provided on one peripheral surface of the differential case. A plurality of guide portions extending linearly in the direction, each ball is movably engaged with each guide portion, and a peripheral surface of the ball disc is provided. Are formed so that grooves engaging with each ball are continuously provided in the circumferential direction, and each groove is formed so that each ball reciprocates along the guide portion when a rotation difference occurs between the differential case and the ball disk. A ball transmission type differential limiting device in which a space in which a ball moves is filled with a viscous fluid, wherein the thrust washer is made of a surface-treated alloy steel or a sintered material. Limiting device. 5. The ball transmission type differential limit according to claim 3, wherein a gap through which a viscous fluid can flow is formed between at least one of the guide portion and the groove and the ball. apparatus. 6. The ball transmission type differential limiting device according to claim 1, wherein the surface treatment of the thrust washer is carburization hardening. 7. The ball transmission type differential limiting device according to claim 1, wherein the surface treatment of the thrust washer is nitriding hardening. 8. The thrust washer according to claim 1, wherein the surface treatment is carbonitriding and hardening.
The ball transmission type differential limiting device according to any one of the above items. 9. The ball transmission type differential limiting device according to claim 1, wherein the surface treatment of the thrust washer is hard chrome plating. 10. The ball transmission type differential according to claim 1, wherein the material of the thrust washer is alloy steel, and the surface treatment is a synthetic resin coating. Motion limiter.