JPH02225827A - Overload clutch - Google Patents

Abstract

PURPOSE:To prevent seizure and abrasion in high speed rotation by releasing a ball from two-point contact with a ball holding and penetrating part at the time of cutting off of overload and by bring it into a rolling contact between both a driven and a pressure plates so as to lighten phase adjustment for restoring engagement. CONSTITUTION:When overload is applied to a driven plate 17, even though rotation of the plate 17 is stopped, an axis A keeps on rotating and a ball 15 is moved to the right direction guided by a root part 14a against a component of a force P, gets out of a ball holding bottom part 18 and moves to a flat 19. This movement is generated by that the ball 15 climbs up from the bottom part 18 to a boundary 18a of the flat part 19 and moves in the axial direction by the length L. In this way, the ball 15 climbs up a slope 19b of a step part 19a. At this time, as an inclination angle phi of the slope 19b is larger than an inclination angle theta of a pressure plate 30, the ball 15 is moved in the same direction by H receiving a component of a force in the radial direction to the outside, released from the contact of a strong wedge action pressed at two points to a notch 14 and freely rotated and held by the plate 30, the flat part 19 and the step part 19a.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a so-called overload clutch for preventing torque transmission when an overload is applied to a driven part.

PRIOR ART AND THE PROBLEM Traditionally, a device has been provided between the drive part and the driven part of a torque transmission mechanism to release the drive torque when the load torque exceeds a predetermined value, thereby preventing damage to the drive and driven side mechanisms. Overload clutches such as ball clutches and roller clutches are one type of safety device to prevent this.

Its structure is such that the torque transmission element is held by a torque transmission element holding penetrating portion formed on one of the hub or the driven plate, and a pressure plate is used to press the torque transmission element holding bottom portion formed on the other of the hub or driven plate to generate torque. The torque transmission is performed, and when an overload occurs, the torque transmission element escapes from the bottomed portion holding the torque transmission element against the pressure, thereby interrupting the torque transmission.

For this reason, in order for the torque transmission element to be held and move within the torque transmission element holding penetration part during the escape, the torque transmission element holding penetration part has a shape that follows the shape of the torque transmission element passing through it (for example, a shape of a ball). The holes were circular for rollers, and square for rollers, with a certain gap between them.

Therefore, the torque transmission element was held in the torque transmission element holding penetration part in a so-called loosely fitted state.

However, with such a configuration, if the rotation direction of the drive side of the overload clutch changes, the above-mentioned gap will cause backlash, the relative position of the hub and the driven plate will be incorrect, and the position between the drive side and the driven side will change. There was a problem with misalignment.

Further, even if the rotational direction is constant, there is a problem in that the re-meshing position of the torque transmission element with the bottomed portion holding the torque transmission element after the overload is eliminated cannot be determined.

Furthermore, in an attempt to reduce the influence of this gap, if distortion removal is performed after heat treatment to increase machining accuracy, there are problems such as time-consuming machining and high costs. .

Therefore, in view of the above-mentioned problems, the applicant has already filed a patent application filed in 1986.
-262764 has been filed for an invention related to an overload clutch that eliminates backlash. The structure is such that, in the above-mentioned overload clutch, an inclined portion is formed in a portion of the pressure plate that contacts the torque transmission element to press the torque transmission element in a direction intersecting the rotation center axis of the overload clutch. The torque transmitting element holding penetrating portion has a 7-shaped shape when viewed from the axial direction, and the torque transmitting element holding bottom portion is a V-shaped groove of an overload clutch.

In the above-mentioned overload clutch, the torque transmitting element is moved by the force generated when the inclined part presses the torque transmitting element, and when transmitting torque, the torque transmitting element is
It is pushed into the V-shaped groove of the 7-shaped part and the bottomed part holding the torque transmitting element, and is supported in two-point contact with each 7-shaped part. It escapes from the V-shaped groove of the bottomed portion holding the torque transmission element and moves to the flat part of the driven plate to release the overload.

Therefore, the torque transmitting element is not loosely fitted into the 7-shaped part of the torque transmitting element holding penetration part by the inclined part, and is always pressed in two-point contact, so that backlash does not occur.

However, even in the event of an overload, the ball is pressed between the driving side and the driven side and contacts the figure 7 part at two points, so transfer is prevented and the ball either slides into contact within the figure 7 part or It slides into contact with the driven plate, and this F! ! Due to friction, even when overload is cut off, there is a so-called "
"dragging torque" will be transmitted.

Therefore, if the overload setting torque is low, the driven side will rotate together, making it difficult to align for remeshing, and if used for a long time in this condition, friction will cause seizure and wear. There is a problem of doing something like that.

Means for Solving the Problems The present invention provides an overload clutch that eliminates the above-mentioned backlash, in which a flat part between the torque transmitting element holding bottomed parts is in a two-point contact state with the torque transmitting element holding penetrating part. The above-mentioned problem has been solved by a configuration in which an inclined step portion having an angle larger than the inclination angle of the inclined portion of the pressure plate is provided on the side of the valley portion of the torque transfer element holding penetration portion from the pitch circle of the torque transfer element.

When transmitting operating torque, the torque transmitting element is held between the bottomed portion holding the torque transmitting element and the pressure plate, and rotational torque is transmitted from the hub to the driven plate.

At the time of overload, the torque transmission element runs onto the flat part from the bottomed part holding the torque transmission element. The torque transmission element receives a component force from the inclined step portion provided on the flat portion in a direction away from the two-point contact of the torque transmission element holding penetration portion. As a result, the torque transmission element is held by the pressure plate, the flat part and the sloped step part, and the torque transmission element holding penetration part and the two
Holds without point contact.

Therefore, the torque transmitting element can be freely relocated.

As described above, by rolling contact, positioning for remeshing can be easily performed.

Embodiments Hereinafter, embodiments of the present invention will be explained based on the drawings, taking a ball clutch as an example.

As shown in FIG. 1, the hub 10 has a flange 13 formed at the center of the Ia' portion 11, and a set screw 12 protrudes from the inner peripheral surface for co-rotation with the shaft A. .

As shown in FIG. 2, the flange 13 has a plurality of V-shaped notches (torque transmission element holding penetration parts) 14 formed radially at uneven intervals and expanding toward the outer periphery. The reason for the uneven spacing is to limit the engagement point in one rotation to one dark place), the valley portion 14a of each notch 14.
A ball (steel ball) 15, which is a torque transmitting element, is pushed in by a configuration described later.

Returning to FIG. 1, a disk-shaped driven plate 17 is provided in the cylindrical portion 11 on the left side of the collar 13 so as to rotate with a radial bearing 16 interposed therebetween.

As shown in FIGS. 3 to 5, on the right side surface 17a of the driven plate 17 facing the #113, a ball holding bottom portion 18, which is a V-shaped groove into which the ball 15 is inserted, is opposite the notch 14. Multiple radial cuts are made at the same location. A flat portion 19 is formed between each notch 14 .

A sloped stepped portion 19a is formed on this flat portion 19.

(11 The slanted step portion 19a has a starting point at a diameter D2 smaller than the diameter D1 of the ball engagement pitch circle, and is continuous with the flat portion 19 while sloping toward the ball holding bottomed portion 18 side.Diameter D
1 is the diameter connecting the center of the ball 15 in a state where the ball 15 contacts the notch 14 at two points.

The direction of inclination is the same as the direction of inclination of pressure plate 30, which will be described later. The angle of inclination φ of the inclined stepped portion 19a is larger than the angle of inclination θ of the pressure plate (FIG. 1).In addition, when the ball 15 runs onto the flat portion 19 from the ball holding bottom portion 18 during overload cutoff, the ball 15 and the edge 19c of the inclined surface 19b, the ball holding bottomed portion 18 extends so as to partially cut out the inclined stepped portion 19a. A thrust bearing 20 is interposed between the right side surface 17a and the collar 13.

A screw 21 is formed at the left end of the cylindrical portion 11 of the hub 10, and a fixed nand 22 is screwed into the screw 21. The fixed napht 22 is
This is for holding the driven plate 17 in close contact with the pressure plate 30 with the thrust bearing 20 in between.

A locking plug 24 is pressed into engagement with the screw 21 at the tip of a set screw 23 provided on the fixing nut 22 to prevent the fixing nut 22 from loosening. A thrust bearing 25 is interposed between the fixing nut 22 and the driven plate 17.

A pressure plate 30 is loosely fitted into the cylindrical portion 11 on the right side of #f13 of the hub 10. The pressure plate 30 faces the collar 13, and near the outer periphery of the 30a is an axis A.
An inclined portion 31 consisting of a conical surface with a downward slope toward the surface is formed. This inclined portion 31 presses the ball 15 against the valley portion 14a of the notch 14 and the ball holding bottom portion 18 by a coil spring 34, which will be described later.

A screw 32 is formed at the right end of the hub 10, into which an adjustment nut 33 is screwed.

A plurality of coil springs 34 and a thrust bearing 35 are interposed between the adjustment nut 33 and the pressure plate 30, and the force with which the pressure plate 30 presses the ball 15 is applied! It! ff, and a lock plug 37 at the tip of the set screw 36 is pressed into engagement with the screw 32 to prevent it from loosening.

Next, the operation will be described with the axis A on the driving side and the driven plate 17 on the driven side, for example.

First, when no overload is applied, that is, when meshing,
The ball 15 is notched in the ball holding bottom part IB by a component force P parallel to the axis A (Fig. 1) of the component force generated by the pressing of the inclined part 31, and by a component force F perpendicular to the axis A. 1
4, 2 points with the trough 14a of the hub 10, 2 points with the ball holding bottom part 1 of the driven plate 17, and 1 point with the inclined part 31 of the pressure plate 30, for a total of 5 points. It is supported by points. Therefore, since the ball 15 is pressed against the ball holding bottom part 18, which is a figure 7 groove, and remains calm, the entire ball clutch rotates as one, and the rotational torque of the shaft A is connected to the driven plate 17. The information is transmitted to a mechanism (not shown).

Next, when an overload is applied to the driven plate 17, the shaft A continues to rotate even though the rotation of the driven plate 17 is prevented, so that the ball 15 resists the component force P and is pushed into the trough 14a. Using the inside as a guide, move to the right in FIG. 1, escape from the ball holding bottomed part 18, and transfer to the flat part 19. This transfer occurs when the ball 15 runs over the boundary 18a (FIG. 5) of the flat portion 19 from the ball-retaining bottom portion 18 and moves in the axial direction by the length shown in FIG. 19a is the ball holding bottom part 1
Since it is notched in the part where the sun extends, the boundary 1.8a where the ball 15 starts to transfer is within the flat part 19 and does not interfere with the edge I9C of the stepped part 19a, D3.
indicates the pitch circle diameter of the ball 15 after transfer.

The ball 15 transferred to the flat part 19 then moves to the stepped part 19
It rides on the inclined surface 19b of a. At this time, the inclined surface 19b
Since the inclination angle φ of the pressure plate 30 is larger than the inclination angle θ of the pressure plate 30, the ball 15 receives a component force radially outward and moves in the same direction by an amount indicated by H in FIG. The ball 15 is connected to the pressure plate 30 and the flat part 1.
8 and the inclined stepped portion 19a.

FIGS. 7 and 8 show the amount of displacement of the ball 15 and the distance between the ball 15 and the notch 1 when the ball 15 rides on the stepped portion 19a.
It shows the relationship of 4. The ball I5, which has moved by a length H in the radial direction, is released from the strong simulated contact of being pressed at two points against the notch I4. In this state, ball 15
The pressure plate 30, the flat part 19 and the stepped part 1
9a will be retained by three parties and can be transferred freely.

In addition, when transferring the ball 15, the ball 15 and the notch 14
Since the gap C is secured between the balls 15, the rotation of the ball 15 is not restricted.

As a result, the hub 10 is able to idle, and rotational torque can be reliably released.

According to the above ball clutch, when engaged, the ball 1
5 is connected to the valley portion 14a of the notch 14 by the inclined portion 31;
The ball retaining bottom part 1, which is a shape groove, is pressed on the hub 1.
Since the hub 10 is supported at two points between the hub 10 and the driven plate 17, even if the rotation direction of the hub 10 changes, there will be no phase shift between the hub 10 and the driven plate 17.

Further, when the overload is cut off, the ball 15 starts to move using the valley portion 14a as a guide, but when it is transferred to the flat portion 19 of the driven plate 17, the ball 15 moves between the pressure plate 30, the flat portion 19, the inclined stepped portion 1. 9a, and is released from two-point contact with the trough 14a of the notch 14 of the hub, allowing for rolling contact.

When the ball 15 returns to the rejoining position after the overload is released, the ball 15 reliably enters the ball holding bottom portion I8 of the driven plate 17 and comes into contact with the valley portion 14a at two points. In other words, they will mesh without backlash.

Further, the ball 15 is rotated around the hub 1 due to the draft during torque transmission.
Since two points are always in contact with 0, the notch 14 settles at a predetermined position regardless of the machining accuracy, and there is no need to remove distortion after heat treatment, and the notch 14 can be manufactured at a low cost.

Note that the notch 14 may be a penetrating portion with a widening shape.

Further, as shown in FIG. 9, the position of the hub flange and the driven plate may be reversed from those in FIG. V-shaped penetration portions 54 having valley portions 54a are formed in the plates 53, respectively. 55 is a retaining ring for regulating the position of the driven plate 53. In this embodiment, the penetration part 5
Since 4 is literally a penetrating portion and not a notch, there is no need to make the left end of the pressure plate 30 into a sleeve shape to prevent the ball from escaping as in the case of FIG.

Furthermore, a notch 14, a penetrating portion 54, a ball holding groove 18 with a bottom
They may be formed at equal intervals of .degree.52.

Effects of the Invention As described above, according to the overload clutch of the present invention, when engaged, the torque transmission element is always in two-point contact with the torque transmission element holding penetration part without loosely fitting, so that the torque transmission of the torque transmission element is prevented. The position with respect to the element holding penetration part is always constant, so there is no deviation in the relative position of the hub and driven plate. Also, even after the overload is removed, the torque transmission element is securely located in the bottomed part holding the torque transmission element. This ensures re-meshing.

In addition, since the shape of the torque transmission element holding penetrating portion does not require precision, machining becomes easier and costs can be reduced.

Further, when an overload is cut off, the torque transmission element is released from two-point contact with the torque transmission element holding penetration part, and comes into rolling contact between the pressure plate and the driven plate. Therefore, the phase adjustment for returning to remeshing becomes extremely easy, and there are effects such as suppressing seizure and wear phenomena at high speed rotation.

[Brief explanation of the drawing]

1 to 9 show embodiments of the overload clutch according to the present invention, in which FIG. 1 is an axial sectional view, FIG. 2 is a view of the hub as seen in the 2-2 line direction of FIG. 1, 3 is a view of the driven plate seen in the direction of line 3-3 in FIG. 1, FIG. 4 is a view of FIG. Fig. 6 is a partial cross-sectional view showing the relationship between the torque transmitting element and the bottomed part holding the torque transmitting element during meshing, Fig. 7 is a partial cross-sectional view of the torque transmitting element and the flat part and the sloped step part when overload is cut off; FIG. 8 is a front view showing the relationship between the torque transmitting element and the torque transmitting element holding penetration part at the time of overload interruption, and FIG. 9 is an axial cross-sectional view showing another embodiment. Fig. 1 0.50...Hub 3.51...Brim 4...Notch (torque transmission element holding penetrating part) 4a...
Valley portion 5... Ball (torque transmission element) 7.53... Driven plate 8... Ball holding bottomed part (torque transmission element holding bottomed part) 9... Flat part 9a... Inclined step part 0 ...Pressure plate... Inclined part 0... Roller (torque transmission element) 4... Penetration part (torque transmission element holding penetration part) Fig. 2 Fig. 3 Fig. 6 Fig. 7 Fig. 8 Figure 9 Figure 4 Procedural amendment June 5, 1999

Claims (1)

[Scope of Claims] The torque transmission element is held by a torque transmission element holding penetration portion formed on one of the hub or the driven plate, and is pressed by a pressure plate against the torque transmission element holding bottom portion formed on the other side of the hub or driven plate. In the overload clutch, the torque transmission element is configured to transfer torque by resisting the pressure and escape from the bottomed portion holding the torque transmission element when overloaded.
A slope portion that presses the torque transmission element in a direction intersecting the rotational center axis of the overload clutch is formed in a portion of the pressure plate that contacts the torque transmission element, and the torque transmission element holding penetration portion is formed so that the torque transmission element holding penetrating portion is formed from the axial direction. The shape when viewed is V-shaped, the bottomed portion holding the torque transmission element is a V-shaped groove, and the flat portion between the bottomed portions holding the torque transmission element is in two-point contact with the torque transmission element holding penetrating portion. An overload clutch, further comprising an inclined step portion having an angle larger than the inclination angle of the inclined portion of the pressure plate, on the side of the valley portion of the torque transfer element holding penetration portion from the pitch circle of the torque transfer element.