JPH0426A - Manual reset type overload clutch - Google Patents

Abstract

PURPOSE:To control the trip torque mechanically, and enable the manual reset when the torque is cut-off by falling a ball into an annular channel to hinder the work of the spring force against a pressure plate. CONSTITUTION:When an overload is applied to a driven plate 40, rotation of the a plate 40 is hindered, but inspite of it, since a shaft A continues to rotate, a torque transmitting element 12 tries to escape from a V-shape long channel 26. When the element 12 pushes a pressure plate 30 right, resisting the pushing force of a coil spring 32, a ball 37 is fallen into an annular channel 61 at an instant that a movement quantity of the element 12 exceeds a dimension A, and the pushing force in the axial direction does not work to the plate 30. Phases of the element 12 and the channel 26 are matched with each other to move the plate 30 left. Since the ball 37 receives the force of the outside in the radial direction to be caused by the pushing force of the spring 32 from a channel surface 63 of the channel 61, the ball 37 escapes from the annular ring 61 automatically, and the ball 37 abuts on a taper surface 51 of the plate 30 again to reset the torque transmission condition.

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. The following will relate to an overload clutch that maintains a state in which torque transmission is cut off unless it is manually and intentionally restored.

PRIOR ART AND THEIR PROBLEMS Traditionally, a torque transmitting mechanism is provided between the driving part and the driven part, so that the load torque reaches a predetermined value (this is called "trip torque").
That's what it means. ) Overload clutches, such as ball clutches and roller clutches, are a type of safety device that releases the drive torque and prevents damage to the drive and driven mechanisms.

One type of overload clutch is an electromagnetic type. An electromagnetic overload clutch is one in which the torque transmission element is placed in a recess formed on both the drive side and the driven side, and the trip torque between the drive side and the driven side is adjusted using a magnet and a leaf spring. It is.

However, since the trip torque is adjusted electrically, there are problems such as the electrical noise generated by the overload clutch having a negative effect on peripheral equipment, and the noise and vibration caused by the leaf springs flapping when the overload clutch is activated. There's a problem.

In addition, in recent years, manual return There is a need for a type overload clutch.

In order to solve the above problems, the object of the present invention is to provide a machine that can mechanically adjust the trip torque of an overload clutch, and that can also perform manual return in response to recent demands. Our goal is to provide a unique overload clutch.

Means for Solving the Problems The present invention provides a method for holding a torque transmitting element by a torque transmitting element holding penetration formed on one of a hub or a driven plate, and a torque transmitting element formed on the other of the hub or driven plate by a pressure plate. In the overload clutch, the torque transmission element is pressed against the holding bottom part by a spring to transmit torque, and when overloaded, the torque transmission element escapes from the torque transmission element holding bottom part against the pressure. An inclined part that presses the torque transmission element in a direction intersecting the rotational center axis of the overload clutch is formed in the part of the pressure plate that contacts with the overload clutch, and the torque transmission element holding penetration part has a shape of 7 when viewed from the axial direction. The bottomed portion holding the torque transmission element is a 7-shaped groove, and a tapered surface is provided at the corner of the inner peripheral portion on the spring side of the pressure plate, and the ball is connected to the outer peripheral cylindrical surface of the hub and the tapered surface. and on the outer peripheral cylindrical surface of the hub on the spring side from the position of the ball during torque transmission. The above problem was solved by an overload clutch in which an annular groove is provided in the clutch, and when the torque is cut off, the pole falls into the annular groove so that the spring force does not act on the pressure plate.

In the operating torque transmitting state, the torque transmitting element receives a pressing force from the spring via the ring and the ball and engages with the torque transmitting element holding bottom portion. Due to this pressing force, the torque transmission element is pushed into the figure 7-shaped part of the torque transmission element holding penetrating part and the figure 7 groove of the bottomed part holding the torque transmission element, and is supported in two-point contact with each figure 7 part. ing. Therefore, the torque transmitting element is not loosely fitted into the 7-shaped part of the torque transmitting element holding penetrating part by the inclined part, and is always pressed in two-point contact, so that backlash does not occur.

When a torque greater than a predetermined value is generated between the hub and the driven plate, the torque transmission element presses the pressure plate and compresses the spring via the ball and ring. The pressure plate, pole and ring are moved axially by the escape movement of the torque transmitting element. Here, an annular groove is provided on the outer periphery of the hub, and the ball receives a component force in the fine direction from the tapered surface of the pressure plate.
When the torque transmitting element approaches the annular groove during axial movement, it falls into this annular groove.

At this time, no axial pressing force acts on the pressure plate. That is, the pressing force of the spring acts on the annular ring and the ball, but only a radially outward force acts from the ball on the pressure plate. This is because the ball retreats from the movement trajectory of the pressure plate. Therefore, the force that opposes the movement of the torque transmitting element to completely escape from the torque transmitting element retaining bottom portion is eliminated, and the pressure plate is allowed to move further in the axial direction. The annular groove absorbs the axial pressing force from the ball. In this way, once an overload is applied, the torque cut-off state is maintained.

Returning to the torque transmitting state is performed by aligning the phases of the torque transmitting element and the bottomed portion holding the torque transmitting element, and manually moving the pressure plate in the axial direction. The shape of the annular groove is such that the ball can escape from it due to the pressing force of the spring, and for example, it may be shaped like a square or have a depth shallower than the radius of the ball. Therefore, when the pressure plate returns to its original position, the ball receives a radially outward force from the annular groove, escapes from the annular groove, contacts the tapered surface of the pressure plate again, and transfers the pressing force of the spring in the axial direction. Begins to communicate. In this way, the torque transmission state can be restored.

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

The overload clutch 10 according to the first embodiment of the present invention includes:
As shown in FIG. 1, the hub 20 and the driven plate 40
It has.

As shown in FIG. 2, the driven plate 40 has a plurality of V-shaped notches (torque transmitting element holding penetration portions) 41 that are formed radially at irregular intervals and spread toward the inner periphery. The reason for this uneven spacing is that the meshing point 1 in one rotation is
This is to limit ~ to one location. Note that it is naturally possible to arrange a plurality of notches at equal intervals to create an overload clutch that can engage at a plurality of points.

A ball (steel ball) 12, which is a torque transmission element, is pushed into the valley portion 42 of each notch 41 by a configuration described later.

This driven plate 40 is connected to the coupling flange 1
3.14 has a screw hole 43 for fixing. The coupling flange 13,14 is attached to one axis B with a cylindrical part. Reference numeral 15 denotes a known device for fastening the coupling flange 14 and the shaft B, and the coupling flange 14 and the shaft B are fastened together by a pressure flange 16 and bolts 17 using the wedge action of the taber ring.

The hub 20 has a flange 22 formed at one end of a cylindrical portion 21, and a threaded portion 23 on the outer periphery and an enlarged diameter portion 24 on the inner periphery at the other end.
, a screw hole 25 is formed in the end face. The fastening device 18 inside the enlarged diameter portion 24 is similar to the one indicated by the reference numeral 15 described above, and the hub 20 and the shaft A are fastened together by the pressure flange 19 and bolts 17.

As shown in FIGS. 3 and 4, on the inner surface of the collar 22, V-shaped long grooves (bottomed portions holding torque transmitting elements) 26 are provided radially at irregular intervals in the circumferential direction. (2) The expansion groove 26 has the same phase as the above-mentioned notch 41. A flat portion 27 is formed between the V-shaped long grooves 26 in the collar 22.

Returning to FIG. 1, a pressure plate 30 is loosely fitted into the cylindrical portion 21 of the hub 20 with a gap provided on the inner periphery. The surface of the pressure plate 30 facing the flange 22 has a sloped portion 31 forming a conical surface at a portion thereof sloped so as to face the valley portion 42 of the notch 41 of the driven plate 40.
It becomes.

The inclined portion 31 has a function of pressing the torque transmission element 12 against the valley portion 42 and the bottom portion 28 of the V-shaped groove 26 by a coil spring 32 to be described later.

An adjustment nut 33 is screwed into the threaded portion 23 at the other end of the hub 20 . A plurality of coil springs 32, a ball retaining ring 36, and balls 37 are provided between the adjusting nut 33 and the pressure plate 30. The adjustment nut 33 is used to adjust the force with which the pressure plate 30 presses the torque transmission element 12. After adjustment, the set screw 34 provided on the adjustment nut 33 is screwed in, and the lock plug 35 at the tip thereof is pressed into engagement with the threaded portion 23 to prevent loosening. The coil springs 32 press the pressure plate 30 with individual biasing forces.

The wall thickness of the torque transmission element holding portion of the driven plate 40 is thinner than the diameter of the torque transmission element 12, and in a stationary state, between the pressure plate 30 and the collar 22,
They are arranged with a gap between them. The pressing force from the pressure plate 30 is applied to the inclined portion 31 of the pressure plate 30.
The torque transmitting element 1 is moved in the direction of the trough 42 of the notch 41 of the driven plate 40 and in the direction of the bottom 28 of the V-expanded groove 26.
Press 2 to make two points contact with each.

Due to this pressing force, the driven plate 40 is placed in the same position as the radial force against the pressure plate 30,
It is in a state floating above the hub 20.

Note that movement in the axial direction is free by the amount of the gap. Further, the pressure plate 30 is also in a floating state from the hub 20. However, even in the floating state, backlash does not occur because the torque transmission element 12 contacts the notch 41 of the driven plate 40 and the V-expanded groove 26 of the collar 22 at two points each. Therefore, the hub 20 on axis A, the driven plate 40 and the coupling flange 13.1 on axis B.
Even if there is a spacing error when installing the driven plate 40, the driven plate 40 is allowed to move relative to the hub 20 in the axial direction. Further, even if there is an angular error between the axis A and the axis B, the driven plate 40 can be tilted to absorb the error.

Furthermore, as shown in FIG.
1 is formed. Ball retaining ring 36 has a through hole 38 for retaining ball 37. This through hole 38 is completely cylindrical. The right side of the ball retaining ring 36 receives the biasing force of the coil spring 32, and the left side presses the ball 37 accurately in the axial direction. The inner diameter of the ball retaining ring 36 is such that it can slide freely on the outer cylindrical surface 60 of the hub 20. The ball 37 held by the ball retaining ring 36 acts as a bearing when the adjusting nut 33 is tightened, so that the adjusting nut 33 can be tightened smoothly, and a thrust bearing, etc., which was required in the past, can be incorporated. It doesn't need to be done.

The ball 37 has a diameter d (FIG. 6) larger than the distance t between the outer cylindrical surface 60 of the hub 20 and the inner circumferential surface 52 of the pressure plate 30, and in the torque transmission state, the outer cylindrical surface 60 of the hub 20, the pressure It is held between three points: the tapered surface 51 of the plate 30 and the through hole 38 of the ball retaining ring 36.

The forces acting on the ball 37 include the axial pressing force PL from the coil spring 32 via the ball retaining ring 36, the reaction force P2 from the tapered surface 51 of the pressure plate 30, and the reaction force from the outer cylindrical surface 60 of the hub 20. P3, and these forces are balanced.

In addition, P4. P5 is a force obtained by decomposing the reaction force from the tapered surface 51 of the pressure plate 30 to the ball 37 into an axial component force and a radial component force. Therefore, P1=P4: P3=P5. In this way, all of the pressing force of the coil spring 32 acts as a force that causes the torque transmission element 12 to engage with the V-shaped expansion groove 26. In this way, since the balls 37 are arranged so as to be in contact with the outer circumferential cylindrical surface 60 of the hub 20, an overload clutch 10 suitable for reducing the size of the spring 32 can be obtained.

The outer cylindrical surface 60 of the hub 20 is formed with a ■-shaped annular groove 61 . The annular groove 61 extends from the point of contact between the ball 37 and the outer cylindrical surface 60 of the hub 20 in the torque transmitting state.
It has a starting point 62 only on the spring side. This dimension A is
It is shorter than the amount of movement when the torque transmission element 12 escapes from the V expansion groove 26, and the torque transmission element 12 moves away from the V expansion groove 26.
The ball 37 is configured to approach the starting point 62 of the annular groove 61 before completely escaping from the annular groove 61.

During torque transmission rotation, when no overload is applied, the pressure plate 30 presses the torque transmission element 12 to the 7-shaped notch 41 of the driven plate 40 and the V expansion groove 26 of the collar 22 of the hub 20. Since both axes A and B are in contact with each other at two points and settled down, even if an angle error or interval error occurs during the 0 rotation when the shafts A and B rotate as one and torque is transmitted, as mentioned above, there will be no overflow. - These errors can be absorbed by the road clutch 10 itself. Naturally, no backlash occurs.

Next, when an overload is applied to the driven plate 40, the shaft A continues to rotate even though the driven plate 40 is prevented from rotating, so the torque transmission element 12 tries to escape from the V-expanded groove 26.

When the torque transmission element 12 presses the pressure plate 30 to the right against the pressing force of the coil spring 32, the ball 37 approaches the annular groove 61. Since the distance to the annular groove 61 is shorter than the amount of movement of the torque transmitting element 12, the ball 37 moves into the annular groove 61 as shown in FIG. reaches the starting point 62. This behavior occurs because P4 > PL.

FIG. 7 is a diagram showing immediately after the amount of movement of the torque transmission element 12 and pressure plate 30 exceeds A. At this time, assuming that the angle of the tapered surface 51 of the pressure plate 30 is 45'', P5 > 0, and a force in the direction of falling into the annular groove 61 acts on the ball 37. The moment the amount of movement exceeds dimension A, the ball 37 moves into the annular groove 61.
I feel depressed.

FIG. 8 shows a state in which the ball 37 has fallen into the annular groove 61 and retreated from the movement trajectory of the pressure plate 30. The ball 37 is in a state where it has been moved by a dimension B1 in the axial direction and a dimension d- in the radial direction from the center position (FIG. 6) just before it falls into the annular groove 61.

At this time, the ball 37 contacts the through hole 38 of the ball retaining ring 36, the inner circumferential surface 52 of the pressure plate 30, and the groove surface 63 of the annular groove 61 at three points, and the pressing force of the coil spring 32 causes the pressure plate 30 to It does not act to push leftward. That is, the pressing force P1 of the coil spring 32, the reaction force P6 from the inner circumferential surface 52 of the pressure plate 30, and the reaction force P7 from the groove surface 63 of the annular groove 61 are balanced, and the pressing force of the coil spring 32 is equal to Groove surface, 6
It is canceled out by the axial component force from 3. Therefore, ball 37
Once it falls into the annular groove 61, no axial pressing force acts on the pressure plate 30 anymore.

Here, the dimensions A1, B1, and C (the axial dimension from the center of the ball 37 to the end of the inner peripheral surface of the tapered surface 51) and the amount of movement of the torque transmission element 12 (denoted as L) satisfy the following relationship. Set it as follows.

A+B+C≦L If A+B+C exceeds L, when the torque transmission element 12 completely escapes from the V-expanded groove 26, the ball 37 has not yet completely retreated from the movement trajectory of the pressure plate 30, resulting in an overload. This is because when the coil spring 32 is released, the pressing force of the coil spring 32 acts on the pressure plate 30, and the torque transmission element 12 automatically returns to the V expansion groove 26.

In addition, when A0B0C is full, the ball 37 is in a position where it interferes with the edge of the tapered surface 51 of the pressure plate 3o, so in order to ensure the torque cutoff state, it is necessary that A+B0C<L. desirable. The allowance for this is indicated by the symbol in FIG.

As described above, when an overload is applied to the driven portion, the torque is interrupted at the moment the ball 37 rolls on the outer cylindrical surface 60 of the hub 2o and reaches the starting point 62 of the annular groove 61. The pressing force of the coil spring 32 acting on the torque transmission element 12 is transmitted in the axial direction at 100% (theoretical value ignoring friction loss, etc.). Since the distance from the point of contact between the ball 37 and the outer cylindrical surface 60 of the hub 20 to the starting point 62 of the annular groove 61 in the torque transmission state is a straight line, it is easy to set the distance.

In order to return to the torque transmitting state from the torque cutoff state, first, the torque transmitting element 12 and the V-shaped expansion groove 26 are aligned in phase, and the pressure plate 3° is moved to the left in FIG. Since the ball 37 receives a radially outward force from the groove surface 63 of the annular groove 61 due to the pressing force of the coil spring 32, the ball 37 automatically escapes from the annular groove 61. In this way, the ball 37 comes into contact with the tapered surface 51 of the pressure plate 30 again, and the torque transmission state is restored.

FIG. 9 shows a second embodiment of the invention. That is,
Like the overload clutch disclosed in Japanese Patent Application No. 1-43136 filed by the same applicant, a V-shaped notch 141 that expands outward is provided on the hub 120 side, and a V-shaped expansion groove 126 is formed on the driven side. The torque transmitting element 112 is disposed in the pressure plate 130.
12 in the direction of the V expansion groove 126 to transmit torque, and a ball retaining ring 136 and a ball 137 are placed between the pressure plate 130 and the coil spring 132.
This ball 137 is placed in the hub 120 when overloaded.
There is also one that fits into an annular groove 161 formed on the outer cylindrical surface of the cylinder.

The foregoing describes preferred embodiments of the present invention and is not intended to be limiting. Therefore, the following modifications are also included in the present invention.

First, the shape of the annular groove is not V-shaped as shown in FIGS. 5 to 8, but may be formed so that the surfaces perpendicular to the axis face each other. Alternatively, one may be perpendicular to the axis and the other may be inclined in a V-shape.

Second, the relationship between the V-shaped notch and the V-shaped expansion groove is different from that in the above embodiment, in which the V-shaped notch and the V-shaped expansion groove are arranged in the axial direction.
As in No. 21894, it may be configured to be arranged in the radial direction.

Effect of the invention Since the present invention has the above configuration, it has the following effects.

(1) During torque transmission, the torque transmission element does not loosely fit into the torque transmission element holding bottomed part and is always in contact at two points, so the position of the torque transmission element with respect to the torque transmission element holding penetrating part is always constant. Therefore, there will be no deviation in the relative position of the driven plate of the hub. Moreover, remeshing is reliable.

(2) Trip torque can be set mechanically, and electrical noise that adversely affects peripheral equipment is not generated.

(3) Since the ball is in contact with the tapered surface of the pressure plate and the outer cylindrical surface of the hub, almost 100% of the spring force is transmitted to the torque transmission element, compared to the conventional method of transmitting it through multiple tapered surfaces. Compared to conventional springs, trip torque can be managed more accurately, and the spring can also be made smaller and lighter.

(4) Torque is interrupted when the ball rolls on the outer cylindrical surface of the hub and approaches the starting point of the annular groove, so the contact point between the ball and the hub in the torque transmission state and the starting point of the annular groove from this contact point The trip torque can be set based on the axial spacing required. In this case, the trip torque can be accurately and easily managed simply by managing the linear spacing, and the trip torque management is easier than with a conventional overload clutch consisting of a plurality of tapered surfaces.

(5) Furthermore, by providing the annular groove on the outer cylindrical surface of the hub, the number of parts can be reduced, and there is no need to accurately process the tapered surface, so manufacturing costs can be reduced.

[Brief explanation of the drawing]

Fig. 1 is an axial sectional view of the overload clutch according to the first embodiment of the present invention in the torque transmission state, Fig. 2 is a front view of the driven plate, Fig. 3 is a front view of the hub, and Fig. 4 is the third embodiment of the overload clutch. The first side of the figure, FIGS. 5 to 8 are partially enlarged sectional views of FIG. 1 for explaining the operation when changing from the torque transmission state to the torque cutoff state, and FIG. 9 is a second embodiment of the present invention. FIG. 3 is an axial cross-sectional view of the overload clutch in a torque transmission state. 10... Overload clutch 12.112... Torque transmission element 20.120... Hub 22... Flange 26, 126... V expansion groove (bottomed portion holding torque transmission element) 27... Flat Part 28...Bottom part 29...Incline step part 30.130...Pressure plate 31...Incline part 32.132...Coille f-ne 36, 136...Ball 37.137
... Ball holding 1 nong 40 ... Driven plate 41.141 ... V-shaped notch (torque transmission element holding penetration part) 42 ... Valley 51 ... Chee 1\face 52 ...
Inner peripheral surface 60...Top circumferential cylindrical surface 61, . 161...
・Annular groove Fig. 2 Fig. 3 Fig. 5

Claims (1)

[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
Torque is transmitted by pressing a bottomed part holding a torque transmission element formed on the other side of the hub or the driven plate by a pressure plate with a spring, and in the event of an overload, the torque transmission element resists the pressure from the bottomed part holding the torque transmission element. In the 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 a rotation center axis of the overload clutch; The torque transmission element holding penetrating part has a V-shape when viewed from the axial direction, the torque transmission element holding bottom part is a V-shaped groove, and the pressure plate has a tapered surface at a corner of the spring-side inner peripheral part. a ball is arranged so as to be in contact with the outer circumferential cylindrical surface of the hub and the tapered surface and with a ring end surface that is arranged to be pushed in the axial direction by the spring; An annular groove is provided on the outer circumferential cylindrical surface of the hub from the ball position to the spring side, and when torque is cut off, the ball falls into the annular groove so that the spring force does not act on the pressure plate. and overload clutch.