JPH0250332B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a ball clutch, and particularly to a ball clutch, and in particular, a method for controlling torque when an overload is applied to a driven part and torque transmission is no longer performed, that is, trip torque, in the direction of rotation of a driving part. Regarding the different ball clutches.

2. Description of the Related Art A safety device is provided between a driving part and a driven part of a torque transmission mechanism, and when the load torque exceeds a predetermined value, the driving torque is released to prevent damage to the mechanisms on the driving side and the driven side. One type is a ball clutch.

The structure is such that torque is transmitted by pressing a ball between the opposing hub flange and the driven plate, at least one of which has a bottomed ball holding hole, and when overloaded, the ball is released from the ball holding hole. It is designed to escape against pressing force.

However, since the plurality of ball holding holes are formed on one circle, the so-called trip torque is the same in the forward and reverse rotational directions of the drive section of the torque transmission mechanism.

Problems to be Solved by the Invention However, when such a conventional ball clutch is used in a torque transmission mechanism that requires different trip torques depending on the direction of rotation (for example, when opening and closing a water gate), The transmission path of the torque transmission mechanism had to be divided into two, and a ball clutch with a different trip torque set for each transmission path had to be used.

Therefore, conventional ball clutches have had the following problems when used in the above-mentioned applications.

(1) The structure becomes complicated because there are two torque transmission paths.

(2) Each time the rotational direction of the drive unit changes, there is the operational hassle of switching the rotational force transmission path.

(3) Higher production costs.

(4) Requires a lot of space.

Means for Solving the Problems The present invention transmits torque by interposing a ball between the flange of an opposing hub and a driven plate, at least one of which has a bottomed ball holding hole, thereby transmitting an overload. In a ball clutch in which the ball sometimes escapes from the ball holding hole against a pressing force, a plurality of the ball holding holes are arranged concentrically with different diameters, and the ball holding holes on the same circle are arranged in the same direction. In addition, the above-mentioned problem was solved by having the ball holding holes on different circles each have relief portions for the ball in different directions.

Effects The present invention has the above configuration, and when the hub is rotated, for example, in the forward direction, the driven plate rotates integrally with the hub via the ball that is press-engaged with the ball holding hole.

If an overload is applied to the driven plate while the hub is rotating, the rotation direction of the hub will be opposite (reverse direction).
A ball engaged in a ball holding hole having a ball relief portion formed on the side escapes from the ball holding hole using the ball relief portion as a guide. On the other hand, the balls engaged in ball holding holes formed on other circles having different diameters escape directly from the ball holding holes to the flat surface. As a result, driving torque can be released.

A similar phenomenon occurs when the hub is reversed and an overload is applied to the driven plate, but the escape of the ball via the relief part and the escape directly to the flat part are two
Regarding the two concentric circles, the relationship is opposite to that of the case of normal rotation described above.

However, when the ball escapes from the ball holding hole, the ball escapes using the ball relief part as a guide.
Escape resistance is greater when the ball escapes directly from the ball holding hole to the flat surface. Therefore, the resistance force directly escaping from the ball holding hole determines the trip torque. Moreover, since the ball that escapes directly from the ball holding hole is on a different circle depending on the direction of rotation, the maximum drive transmission torque, which is the product of the escape resistance force and the radius of the circle in which the ball holding hole is arranged, is Depends on direction. That is, the trip torque differs depending on the direction of rotation.

Embodiments Hereinafter, embodiments of the present invention will be described based on the drawings.

A hub 11 is inserted into the rotating shaft A and rotates together with the key Aa.

The hub 11 is composed of a collar portion 11a and a cylindrical portion 11b.

On the side surface 11c of the flange portion 11a on the cylindrical portion 11b side, there are half molds ra and rb centered on the axis of the rotation axis A.
A plurality of first ball holding holes 12 and second ball holding holes 13 are formed at equal intervals on each of two concentric circles Sa and Sb. In this embodiment, the number of ball holding holes is three each, but it goes without saying that the number is not limited to this.

The first and second ball holding holes 12 and 13 are
As shown in the figure, it has a conical depression shape. Each of the ball holding holes 12 and 13 is provided with first and second ball escape portions 14 and 15 in the form of grooves that slope downward toward the ball holding holes 12 and 13, respectively.

The first ball escape part 14 extends above the circle Sa.
counterclockwise direction of the ball holding hole 12 (arrow X in Figure 2)
direction) side, the second ball relief part 15 has a circle Sb
In the clockwise direction (arrow Y) of the second ball holding hole 13,
(see FIG. 3).

A tribune plate 16, a pressure plate 17, and a plurality of disc springs 18 are fitted in order into the cylindrical portion 11b of the hub 11, and finally a torque adjustment nut 19 is tightened into the threaded portion 11d of the cylindrical portion 11b. It will be done.

The tribun plate 16 is fitted into a bearing 20 provided on the cylindrical portion 11b, and is fitted with a retaining ring 2.
1, the position is restricted so that it does not move on the cylindrical member 11b. Further, at positions facing the first and second ball holding holes 12 and 13, first and second balls 2 that engage with the holes are provided.
First and second ball holding through holes 24 and 25 for holding balls 2 and 23 are formed.

The pressure plate 17 has balls 22, which protrude from the ball holding through holes 24, 25.
23 into the ball holding holes 12 and 13, and the disc spring 1
8, and the adjustment of the pressing force is as follows:
This is done by changing the position of the torque adjustment nut 19.

The position of the torque adjustment nut 19 is determined by an elastic body 27 at the tip of a machine screw 26 provided on the nut 19.
is pressed against the threaded portion 11d of the cylindrical portion 11b.

In the above configuration, the operation will be explained next.

The explanation will be given assuming that the rotating shaft A (hub 11) is the driving side and the triven plate 16 is the driven side.

When the rotating shaft A rotates counterclockwise (forward rotation) when viewed from the right side of Fig. 1, the hub 11 is rotated via the key Aa.
rotates in the direction of arrow X in FIG.

Then, each of the balls 22 and 23 engaged with each of the ball holding holes 12 and 13 moves into each of the ball holding through holes 2.
Tribune plate 16 is connected to hub 1 via 4 and 25.
1 and rotate in the same direction.

When a predetermined load torque is applied to the driven plate 16, the second ball 23 escapes onto the second ball escape portion 15 and escapes from the second ball holding hole 13. On the other hand, the first ball 22 climbs onto the side opposite to the first ball relief part 14 and directly escapes from the first ball holding hole 12 to the flat part 11c of the collar part 11a.

As a result, the balls 22 and 23 that escaped from the ball holding holes 12 and 13 against the disc spring 18 are
Since it rides on the flat part 11c of the hub 11 and causes the hub 11 to idle, the driving torque can be released. At this time, the second ball 23 escapes through the second ball relief portion 15, so that almost no escape resistance is generated. However, since the first ball 22 escapes directly from the first pocket hole 12, a large escape resistance occurs. Therefore, the product of the escape resistance force of the first ball 22 and the radius ra of the circle Sa becomes approximately the maximum drive transmission torque.

Next, the rotating shaft A rotates counterclockwise, and the hub 1
1 is rotating in the direction of the arrow Y in FIG.
At the same time, the second ball 23 climbs onto the opposite side of the second ball escape part 15 and escapes from the first ball holding hole 12 through the second ball holding hole 1.
Escape directly from 3. Therefore, in this case, the second
The product of the escape resistance force of the ball 23 and the radius rb of the circle Sb becomes approximately the maximum drive transmission torque.

Here, when comparing the maximum drive transmission torque when the drive shaft A rotates counterclockwise and clockwise, it is found that if the ball escape resistance is the same in both cases, a circle Sb with a large radius The ball located in the second ball holding hole 13, that is, the second ball 23
The maximum drive transmission torque is greater when escaping from the vehicle. That is, drive shaft A (hub 11)
When rotating clockwise, the trip torque is greater than when rotating in the opposite direction.

Therefore, according to the above embodiment, the maximum drive transmission torque, that is, the trip torque, differs depending on the direction of rotation of the drive shaft A.

In addition, in the above explanation, the rotation axis A (hub 11)
Although the explanation has been made with the tribune plate 16 as the drive side and the tribe plate 16 as the driven side, it is also possible to use the tribune plate 16 as the drive side and the rotating shaft A (hub 11) as the driven side. however,
In that case, the trip torque is greater when the triven plate 16 rotates counterclockwise when viewed from the right side of FIG. 1 than when it rotates clockwise.

Further, the present invention is not limited to the above-described embodiments, and any structure may be used as long as the trip torque is varied depending on the rotational direction of the rotating shaft A (hub 11).

For example, the ball escape portions 14, 1 of the above embodiments
5 has a groove shape with a downward slope toward the ball holding holes 12 and 13, but as shown by the imaginary line in FIG. 3, it may be a flat groove-shaped ball relief portion 30.

Furthermore, the balls 22 and 23 are pressed against the ball holding holes 12 and 13 by the pressure plate 17, but the ball holding through holes 24 and 25 are bottomed holes, and the balls 22 and 23 are held at the bottom of the holes 24 and 25. Sometimes there is pressure. That is, it may be directly pressed by the driven plate 16. However, in this case, the driven plate 16 must be movable in the axial direction.

Further, when the driven plate presses the ball, a ball holding hole and a ball relief part may be formed in the driven plate.

Also, the shape of the ball holding hole is not conical, but
Sometimes hemispherical.

Effects of the Invention As described above, since the ball clutch of the present invention has different trip torque depending on the rotation direction, the transmission path of the torque transmission mechanism that requires different trip torque depending on the rotation direction can be unified. Its structure is simplified and miniaturized, and production costs are reduced. Furthermore, there is no need for the conventional operation of switching the transmission path.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention; FIG. 1 is an axial sectional view, FIG. 2 is a right side view of the hub, and FIG. 3 is an enlarged sectional view (in the circumferential direction) of the second ball holding hole. Sa, Sb...Concentric circles, 11...Hub, 11a...
...flange, 12, 13... (bottomed) ball holding hole,
14, 15, 30... Ball escape part, 16... Driven plate, 22, 23... Ball.

Claims (1)

[Scope of Claims] 1. Torque is transmitted by interposing a ball under pressure between a driven plate and a flange of an opposing hub, at least one of which has a ball holding hole with a bottom,
In a ball clutch in which the ball escapes from the ball holding hole against the pressing force when overloaded, a plurality of the ball holding holes are arranged on concentric circles with different diameters, and the ball holding holes on the same circle are arranged in the same direction. , the ball holding holes on different circles are in different directions,
A ball clutch characterized in that each ball has a relief part.