JPH112309A - Differential gear - Google Patents

Abstract

PROBLEM TO BE SOLVED: To satisfactorily supply lubricating oil to balls, to reduce moving friction of the balls, and to prevent the balls from pitching, by forming at least one oil groove, which is formed between a pair of disk plates, toward the inner circumference of a ball holder which holds plural balls. SOLUTION: When a differential case 1 is rotated by driving force transmitted from an engine, a ball holder 4 rotates integrally with the differential case 1, and this rotating force is transmitted to a groove 3b of each disk plate 3 through each ball 5, and to right and left driving shafts connected to each disk plate 3. In this case, because an oil groove 4d is formed to a long hole 4c from the inner circumference of the ball holder 4, lubricating oil travels from the oil groove 4d to the long hole 4c, and lubricates the groove 3b of the disk plate 3 and the balls 5. Because an oil route 4e is placed at the crossing part between the inner circumference of the ball holder 4 and the oil groove 4d, lubricating oil is enough supplied over the balls 5.

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 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, a differential is generated. Generally, the pinion gear is allowed to rotate to allow a difference in rotation between the output shafts.
A device that is smaller than such a differential device and has a differential limiting function without adding a special mechanism,
It has been proposed as JP-A-8-170705.

FIG. 3 is a cross-sectional view of the differential disclosed in Japanese Patent Application Laid-Open No. 8-170705, FIG. 4 is a front view of the disk plate in FIG. 3, and FIG. 5 is an enlarged view of the groove in FIG. 6 is an explanatory view in which the grooves in FIG. 4 are developed in a plane. 3 includes a gear case 1, a case cover 2 for closing one end of the gear case 1, a pair of disk plates 3 arranged coaxially to face each other, and each disk plate 3.
And a plurality of balls 5 rotatably held by the ball holder 4.
The gear case 1 has a cylindrical shape with one end opened, and a bearing 1a for supporting one disk plate 3 is provided at the center. A flange 1b is provided around the gear case 1, and the flange 1b has many holes 1 for bolt insertion.
c is provided. A groove (not shown) for fixing the ball holder 4 in the rotation direction is provided on the inner surface of the gear case 1.

[0004] The case cover 2 is formed in a disk shape, and in the center thereof, a bearing 2 for supporting the other disk plate 3 is provided.
a is provided. A flange 2b is formed around the case cover 2, and the flange 2b is provided with a number of holes 2c for bolt insertion. That is, the case cover 2 is assembled to the gear case 1 by bolts (not shown) for fastening the flanges 1b, 2b.

On the opposing surface of each disk plate 3, there is provided a groove 3b in which each ball 5 is rotatably engaged.
Are formed continuously in the circumferential direction, and the other end of each disk plate 3 is provided with a connecting portion 3a for connecting a drive shaft (not shown) on the wheel side.

In FIG. 4 and FIG. 5, a groove 3b includes a first guide section 3b-1 for moving the ball 5 from the radially inner side to the outer side of the disk plate 3, and a groove 5b for moving the ball 5 in the radial direction of the disk plate 3. A second guide section 3b-2 for moving from the outside toward the inside, and a third guide section 3b- for keeping the ball 5 at a position within a predetermined range in the radial direction of the disc plate 3 (in this case, a fixed position in the radial direction). 3 in the circumferential direction. Also, in one disk plate 3, the third guide section 3 is included in the first guide section 3b-1.
b-3 is provided, and on the other disk plate, a third guide section is provided within the second guide section. Thus, when the pair of disk plates 3 face each other, when one (inside or outside) inverted position overlaps with each other, the other inverted position is shifted from each other. The groove 3b has a rotation angle of 90 degrees of the disc plate 3.
The ball 5 is formed so as to reciprocate once in the radial direction with ゜. When the ball 5 is developed linearly, it becomes as shown in FIG. The groove 3b does not transmit a force between the ball 5 and the groove 3b in the radially reversed position and the third guide section 3b-3, but the magnitude of the contact angle with the ball 5 in the section transmitting the force. To make the generated thrust force constant. That is, in FIG. 6, a ≦ a ′, b ≧ b ′, c ≦
When the condition of c, d = d 'is satisfied and an arbitrary ball 5 is located at a position where the force is not transmitted, the entire groove 3b is formed so that any other ball 5 is located at a position where the force is transmitted. Thus, a constant thrust force is always generated regardless of the rotation angle of the disk plate 3.

[0007]

The problem to be solved by the present invention is disclosed in Japanese Patent Application Laid-Open No. 8-170.
The differential device disclosed in Japanese Patent Publication No. 705 can achieve differential of each disk plate by engagement of a ball and a groove, and can obtain a differential limiting effect by utilizing mechanical characteristics of the configuration. Therefore, there is an advantage that the number of parts is small and it can be easily assembled.

In the differential disclosed in Japanese Patent Application Laid-Open No. 8-170705, the ball 5 is angularly restricted by the elongated holes 4c of the ball holder 4 and the first guide section 3b of the groove 3b. -1 from the first guide section 3b-1 of the groove 3b along the second guide section 3b-2 toward the inside or outside in the radial direction.
b ′), (a ′ + (dc)), and the torque is transmitted at (ba) in the second guide section 3b-2. When the ball 5 rolls while engaging with the groove 3b of the disk plate 3, if the supply of the lubricating oil is insufficient, excessive friction occurs between the disk plate and the ball, and the groove of the disk plate 3 is formed. 3b and / or the surface film of the ball 5 is peeled off, that is, so-called pitting, and there is a possibility that a desired thrust force cannot be transmitted as a differential device.

An object of the present invention is to solve the problem described in JP-A-8-170705.
In the differential disclosed in Japanese Patent Application Laid-Open Publication No. H10-260, when the ball rolls while engaging with the groove of the disk plate, a sufficient lubricating oil is supplied between the groove of the disk plate and the ball, thereby forming the groove of the disk plate. It is an object of the present invention to provide a differential device that can transmit a desired thrust force while reducing friction between the ball and the ball.

[0010]

DISCLOSURE OF THE INVENTION The present inventors have conducted intensive studies on the supply of lubricating oil to the grooves of the disk plate and the balls. Using the ball holders arranged between the disc plates, the present inventors have found that lubricating oil can be supplied to the grooves of the ball holder and the balls through the long holes of the ball holders, and arrived at the present invention.

That is, the differential device of the present invention includes a differential case having an opening at one axial end, and a case cover for closing an opening at one end of the differential case.
A pair of disc plates arranged coaxially with each other,
With multiple balls arranged between each disc plate,
A ball holder for holding each ball is accommodated, each ball is movably accommodated in a plurality of long holes provided in the ball holder, and each ball is rollably engaged with a groove provided in each disk plate. Then, the differential case is rotated around the axis by the driving force from the outside, and each ball is reciprocated in the elongated hole of the ball holder while rolling each ball along the groove of each disk plate. In a differential device allowing a rotation difference, at least one or more oil grooves are formed from the inner peripheral portion of the ball holder to the elongated hole. Still further, an oil passage is provided at an intersection between the inner peripheral portion of the ball holder and the groove.

[0012]

FIG. 1 is a cross-sectional view of a differential gear according to an embodiment, and FIG. 2 is a front view of the ball holder in FIG. In the differential device according to the embodiment, components other than the ball holder are the same as those of the differential device shown in FIGS. 1 and 2, an oil groove 4d is formed in the ball holder 4 from the inner peripheral portion 4f toward the elongated hole 4c.
Further, an oil passage 4e is provided at the intersection of the inner peripheral portion 4f of the ball holder 4 and the oil groove 4d.

In the differential device configured as described above, the driving force from the engine (not shown) is applied to the differential case 1.
And the entire differential case 1 rotates around the axis. And when the differential case 1 rotates,
The ball holder 4 rotates integrally with the differential case 1, and the rotational force is applied to the groove 3 of each disc plate 3 via each ball 5.
b, and to the left and right drive shafts connected to each disk plate 3. At this time, since the differential device forms the oil groove 4d from the inner peripheral portion 4f of the ball holder 4 to the elongated hole 4c, the lubricating oil (not shown) supplied to the inner peripheral portion 4f is supplied to the oil groove. 4d to slot 4c
To lubricate the groove 3b of the disk plate 3 and the ball 5. Further, since the oil passage 4e is provided at the intersection between the inner peripheral portion 4f of the ball holder 4 and the oil groove 4d, lubricating oil is supplied from a drive shaft (not shown) connected to the connecting portion 3a of each disk plate 3. When supplying, it becomes an introduction path for lubricating oil. Then, the lubricating oil is sufficiently supplied to the groove 3 b and the ball 5 through the long hole 4. For this reason, the groove 3b
This reduces friction when the ball 5 rolls, prevents pitching, and transmits a desired thrust force.

[0014]

As described above, the differential device according to the present invention is different from the differential device disclosed in Japanese Patent Application Laid-Open No. 8-170705 in that an oil groove is formed from the inner peripheral portion of the ball holder to the elongated hole. Lubricating oil is supplied to the groove of the ball disk and the ball disk from the long holes, and furthermore, an oil path is provided at the intersection of the oil groove and the inner peripheral portion of the ball holder, so that lubricating oil is introduced from the drive shaft. It becomes a path, and lubricating oil can be sufficiently supplied between the groove of the ball disk and the ball, and the friction when the ball rolls in the groove of the disk plate is reduced to prevent pitching. And while achieving the differential of each disk plate by the engagement of the ball and the groove,
The differential limiting effect can be obtained by utilizing the mechanical characteristics of the configuration, and there is an advantage that the number of parts is small and the assembly can be easily performed.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a differential device according to an embodiment.

FIG. 2 is a front view of the ball holder in FIG. 1;

FIG. 3 is a cross-sectional view of a differential device disclosed in Japanese Patent Application Laid-Open No. 8-170705.

FIG. 4 is a front view of the disk plate in FIG. 3;

FIG. 5 is an enlarged view of a groove in FIG. 4;

FIG. 6 is an explanatory diagram in which the grooves in FIG. 4 are developed in a planar shape.

[Explanation of symbols]

1: differential case, 2: case cover, 3: disk plate, 3b: groove, 3b-1: first guide section, 3b-2: second guide section, 3b-3: third guide section, 4: Ball holder, 4c: long hole, 4d: oil groove, 4e: oil path, 4f: inner peripheral part, 5:
Ball, 6: Case cover.

Claims (2)

[Claims] 1. A differential case having an axially open one end,
A case cover for closing one end side opening of the differential case, a pair of disk plates arranged coaxially with each other in the differential case, a plurality of balls disposed between the disk plates, and each ball. A ball holder to be held is housed, each ball is movably housed in a plurality of long holes provided in the ball holder, and each ball is rollably engaged with a groove provided in each disk plate, and Allows differential rotation of each disk plate by rotating the differential case around the axis by the driving force from the shaft and reciprocating in the long hole of the ball holder while rolling each ball along the groove of each disk plate. In the differential device, at least one or more oil grooves are formed from the inner peripheral portion of the ball holder to the elongated hole. Differential to. 2. The differential device according to claim 1, wherein an oil passage is provided at an intersection between the inner peripheral portion of the ball holder and the groove.