JP2585371Y2 - Ball cam - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION This invention relates to a ball cam.

[0002]

2. Description of the Related Art FIG. 5 shows a conventional differential device using a ball cam. In this device, the electromagnetic clutch 20
1 is engaged, the differential torque of the differential mechanism 205 acts on the ball cam 203, the main clutch 207 is engaged by the thrust force, and the differential force of the differential mechanism 205 is limited by the engagement force of each clutch 201, 207. Will be

[0003]

For example, when used in the above-described differential device, the main clutch 207, the differential mechanism 205, the bearing 209, the washer 211 and the like are arranged in the axial direction.
In order to accommodate the ball cam 13 in the thrust member 13, particularly high precision is required for the dimension in the thrust direction of the ball cam 203 (corresponding to the dimension t in FIG. 5B).

Conventionally, this dimension is, as shown in FIG.
It is determined via the contact point between the ball 213 and the slope (cam surface), and therefore, the cam surfaces 215 and 217 require high processing accuracy. Since such a high degree of accuracy is required for machining a slope that is inherently difficult, an error is likely to occur in the axial dimension of the ball cam, and the machining cost, yield, and dimension adjustment after assembly (example of FIG. 5) This is very disadvantageous in terms of adjusting the thickness of the shim 219).

Since the cam surfaces 215 and 217 are not perpendicular to the circumferential direction but perpendicular to the tangential direction of the rotating circle, the ball 213 is pushed along the cam surfaces when pressed by the cam surfaces 215 and 217. 6, the trajectory of the ball is different at each operation, and when the cam ring 223 has an indentation, there is a possibility that a malfunction may occur.

The conventional ball cam cannot address such a problem.

[0007] In view of the above, the present invention provides a ball cam capable of obtaining high dimensional accuracy in the thrust direction without requiring a high processing accuracy, and a ball cam capable of obtaining a stable operation function by holding the ball. The purpose is to provide.

[0008]

The ball cam according to the first invention has a pair of cam members which generate a thrust force by applying a torque by arranging a ball between their cam surfaces, and rotatably holding the ball. A ball holder having a holding part and a spacer part for adjusting a distance between the two cam members.

[0009] The second invention is that in the above ball cam,
The holding portion includes a stopper portion that suppresses a radial outward movement of the ball.

[0010]

The size in the thrust direction is determined by the thickness of the spacer of the ball retainer, unlike the prior art in which the size is determined via the contact point between the ball and the cam surface. Accordingly, high dimensional accuracy can be easily obtained in the thrust direction (first invention).

Further, since the holding portion is provided with the stopper portion for preventing the ball from moving outward in the radial direction, the contact between the ball and the portion other than the cam surface is prevented, and the operation of the ball cam is normally maintained. Device).

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows a differential device using this embodiment, and FIG. 4 shows a power system of a vehicle using this differential device. Hereinafter, the left-right direction is the left-right direction of FIG. 1 and this vehicle, and the upper part of FIG. 1 corresponds to the front of this vehicle (upper part of FIG. 4).

First, the structure of the power system of the vehicle will be described with reference to FIG.

The power system includes an engine 1, a transmission 3, front axles 5, 7, left and right front wheels 9, 11, a propeller shaft 13, and a rear differential 15 (see FIG.
Differential device), rear axles 17 and 19, left and right rear wheels 21 and 23, etc., and the driving force of the engine 1 is transmitted via a transmission 3 to a propeller shaft 13
To rotate.

Next, the rear differential 15 will be described.

The differential case 25 of the rear differential 15 is supported in a differential carrier 27 via bearings 29,29. A ring gear 31 is fixed to the differential case 25, and the gear 31 meshes with a drive pinion gear 33. The gear 33 is formed integrally with the drive pinion shaft 35, and the shaft 35 is connected to the propeller shaft 13 side. Thus, the differential case 25 is driven to rotate by the driving force from the engine 1.

As shown in FIG. 1A, the differential case 25
The left and right hubs 37 and 39 are rotatably arranged coaxially inside. The left hub 37 is splined to the left rear axle 17 and the right hub 39 is splined to the right rear axle 19.

A differential mechanism 41 of a planetary gear type is disposed inside the differential case 25. This differential mechanism 4
Reference numeral 1 denotes an internal gear 43, an outer pinion gear 45 meshing with the internal gear 43, and an inner pinion gear 4 meshing with the internal gear 43.
7 and a sun gear 49 meshing with the same.

The internal gear 43 is formed on the differential case 25. The outer pinion gear 45 is rotatably supported on an outer pinion shaft 51, and the inner pinion gear 47 is rotatably supported on an inner pinion shaft 53. Each of the pinion shafts 51 and 53 includes a left pinion carrier 55 and a right pinion carrier 57.
(Cam member) and both ends are fixed by caulking. The right carrier 57 forms a flange of the right hub 39. 55 and 57 are welded and fixed to each other, and washers 59 and 59 are arranged between the respective pinion gears 45 and 47.

Thus, the differential mechanism 41 is constituted, and the rotation of the differential case 25 (internal gear 43) is divided into the sun gear 49 (hub 37) and the carriers 55, 57 (hub 39) via the pinion gear. Hub 37,
The power is transmitted to the left and right rear wheels 21 and 23 via the transmission 39.

On the left side of the differential mechanism 41, a multi-plate type main clutch 63 for connecting the left hub 37 and the cylindrical portion 61 of the left carrier 55 is arranged. A washer 67 is disposed between the clutch 63 and the left side wall 65 of the differential case 25, and a shim 69 is disposed between the carrier 55 and the clutch 63.
Is arranged.

A cam ring 71 is provided on the right side of the carrier 57.
(Cam member) is arranged, and a multi-plate pilot clutch 73 for connecting the cam ring 71 and the differential case 25 is arranged between the cam ring 71 and the differential case 25. An armature 75 is provided on the left side of the clutch 73 so as to be freely movable in the axial direction.
1 and spline engagement.

As shown in FIGS. 1B and 2, a ball cam 79 is formed between the carrier 57 and the cam ring 71 via a ball 77.

The ball cams 79 are formed at four locations having the same diameter and at the same distance, and a ring-shaped ball retainer 81 is arranged between the carrier 57 and the ring 71 as shown in FIG. The holder 81 includes a spacer 83 between the cams 79 and a holder 85 for rotatably holding the ball 77. The spacer portion 83 contacts the carrier 57 and the ring 71, and determines the size of the ball cam 79 in the thrust direction. A slight gap is provided between the ball 77 and each of the cam surfaces 87 and 89 by the spacer portion 83. The holding portion 85 is a cam surface 87 of the ball 77,
The portion other than the contact side with 89 is covered, and the ball 77 is centered with respect to its center. Holder 85
A radially outer portion of the ball is a stopper portion 91, which prevents the ball 77 from moving outward by being pushed by the cam surfaces 87 and 89. Therefore, the ball 77 is
The first spline portion 93 is pressed against the back surface or the inner periphery of the armature 75, and there is no play or indentation which may cause noise.

Even if indentations are formed on the cam surfaces 87 and 89, the trajectory of the ball is constant, so that no malfunction occurs.

The ball retainer 81 is formed by spot welding or caulking two ring members together, and the joint thereof and the center of the ball 77 are offset by the dimension e in FIG. 2 to the left in the axial direction. I have.

As described above, the ball 77 and each cam surface 8
7 and 89, a slight gap is provided. At this time, when the spacer portion 83 is in contact with the pair of cam members, that is, the carrier 57 and the cam ring 71, and receives torque, at this time, The gap between the two cam surfaces and the ball comes into contact with each other and the gap disappears, causing thrust. Since this time is the time of the thrust occurrence, the ball cam 7
9 is determined by the ball retainer 81 and, unlike the conventional example, does not depend on the contact point between the ball 77 and the cam surfaces 87 and 89. Therefore, it is easy to improve the accuracy of the thrust direction dimension. Since the cam surfaces 87 and 89 are released from such a requirement, machining is easier accordingly.

Therefore, the cost of the ball cam 79 is reduced, and the thickness adjustment of the shim 69 is easy.

The ring 71 and the right side wall 95 of the differential case 25
Between the needle bearing 97 and washer 9 from the left
9 are arranged.

On the right side of the right side wall 95, a ring-shaped electromagnet 1
01 is arranged. The electromagnet 101 is a bearing 10
3 and is supported on the right cylindrical portion 105 of the differential case 25 via a support member 107 and is fixed to the differential carrier 27 by a bolt 109 via a support member 107. A non-magnetic ring 111 is embedded in the right side wall 95 to prevent the magnetic force of the electromagnet 101 from being short-circuited and to guide the armature 75 to the armature 75.

When an exciting current is supplied to the electromagnet 101 and the armature 75 is attracted, the pilot clutch 73 is engaged, and the cam ring 71 is connected to the differential case 25 via the clutch 73. The cam ring 71 is the ball cam 7
9, the differential rotation between the internal gear 43 and the pinion gears 45 and 47 is limited in accordance with the engagement force (slip) of the clutch 73, and the differential of the differential mechanism 41 is limited. .

When the clutch 73 is engaged, the differential torque of the differential mechanism 41 acts on the ball cam 79, and
As shown in (b), the left and right cam thrust forces 113, 1
15 results. Carrier 5 with left thrust force 113
5 and 57 move to the left and press the main clutch 63 between the carrier 55 (the shim 69) and the differential case 25 (the washer 67) to be engaged. Thus, the engagement force of the main clutch 63 is added to the engagement force of the pilot clutch 73, and the differential limiting force of the differential mechanism 41 is strengthened. The right thrust force 115 is input to the differential case 25 via the bearing 97 and the washer 99, and the left thrust force 113
Offset by

The pilot clutch 7 is driven by the electromagnet 101.
When the slip of the third mechanism is adjusted, the thrust force 113 changes, and the engagement force of the main clutch 63 changes, so that the differential limiting force of the differential mechanism 41 can be controlled. If the fastening force of each of the clutches 63 and 73 is sufficiently large, the differential is locked, and if the fastening force is moderately reduced, the differential is allowed. When the clutch 73 is released, the clutch 63 is also released and the differential becomes free.

The operation of the differential limiting function by the electromagnet 101 can be manually operated from the driver's seat, or can be automatically operated according to road surface conditions, vehicle operating conditions, and the like.

Thus, the rear differential 15 is formed.

In the vehicle shown in FIG.
Even if one of the tires 1 and 23 slips, the running performance is maintained by the driving force sent to the other rear wheel by the differential limiting force of the rear differential 15. If the differential limiting force of the rear differential 15 is increased, the straight running stability of the vehicle is improved, and if the differential limiting force is reduced, the differential rotation between the rear wheels is allowed and smooth turning can be performed.

As described above, since the carrier 57 and the cam ring 71 are not indented by the ball 79, play and noise are prevented, and the durability is extended.

The use of the ball cam of the present invention is not limited to a differential device.

[0039]

According to the ball cam of the present invention, since the ball cage is mounted and the dimension in the thrust direction is determined by the spacer portion, it is easy to obtain high accuracy in the dimension in the thrust direction. Since excessive dimensional accuracy is not required, the cost is reduced accordingly, and dimensional adjustment between related members is facilitated.

In the embodiment in which the holding portion is provided with a stopper portion for preventing the ball from moving radially outward, no indentation is formed, rattling and noise are prevented, and durability is improved.
Since the trajectory of the ball is constant, no malfunction occurs due to the indentation of the cam surface.

[Brief description of the drawings]

FIG. 1A is a cross-sectional view of a differential device using one embodiment, and FIG. 1B is a cross-sectional view taken along line AA of FIG.

FIG. 2 is a sectional view of a main part of the embodiment.

FIG. 3 is a front view of the ball retainer.

FIG. 4 is a skeleton diagram showing a power system of a vehicle using the differential device shown in FIG. 1;

FIG. 5A is a cross-sectional view of a differential device using a conventional example, and FIG. 5B is a cross-sectional view taken along line AA of FIG.

FIG. 6 is a partially enlarged view of a conventional example.

[Explanation of symbols]

 57 Differential carrier (cam member) 71 Cam ring (cam member) 77 Ball 79 Ball cam 81 Ball retainer 83 Spacer portion 85 Holding portion 87, 89 Cam surface 91 Stopper portion

Continuation of the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F16H 35/04 F16H 25/06 F16D 27/10 F16D 47/00

Claims (2)

(57) [Scope of request for utility model registration] 1. A pair of cam members for generating a thrust force by arranging a ball between respective cam surfaces and receiving a torque,
A ball holder having a holding portion for rotatably holding the ball and a spacer portion for adjusting the interval between the two cam members, wherein when the spacer portion comes into contact with the two cam members, the ball is brought into the cam surfaces of the two cam members. A ball cam characterized by having a slight gap between the ball cam. 2. The ball cam according to claim 1, wherein the holding portion includes a stopper for suppressing the outward movement of the ball in the radial direction.