JPH04160230A - Torque limiter - Google Patents

Abstract

PURPOSE:To obtain a compact torque limiter by containing first balls, which transmit and cut off the torque through engaging and disengaging with an engaging recess of an annular body, a second ball, which presses the first balls, and an energizing means, which makes the second ball generate the energizing force, in a cylindrical body. CONSTITUTION:In a torque limiter 10, energizing force of an energizing means 34 is transmitted to first balls 28 with a prescribed pressure angle torque a second ball 30, and the first balls 28 are pressed in the outside diameter direction along the torque holes 24 formed in a cylindrical body 14. Then, the first balls 28 engage with engaging recesses 26 of an annular body 18, and transmission of the torque between the cylindrical body 14 and the annular body 18 becomes possible. On the other hand, when a load larger than the allowable transmission torque determined by the energizing ability of the energizing means 34 is applied between the cylindrical body 14 and the annular body 18, the first balls 28 move toward the inside along the torque holes 24 moving the second ball 30 against the enforcing thrust, and disengage from the engaging recess portions 26. Consequently, the cylindrical body 14 and the annular body 18 rotate relatively, and the transmission of the torque is cut off.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention is a device that is installed between a driving body that outputs rotational force and a driven body that is rotationally driven by the driving body, and that is usually used to transfer the torque of the rotating body. The present invention relates to a torque limiter that transmits rotational motion to a body and releases the transmission of rotational motion when an overload exceeding a predetermined transmission limit torque value acts between them.

(Prior Art) Conventionally, as this type of torque limiter, there is one described in, for example, Japanese Unexamined Patent Publication No. 1-69918.

That is, in such a torque limiter, rotating bodies each made of a cylindrical boss member having a flange are arranged on the outer peripheries of a driving shaft and a driven shaft, which are disposed coaxially, so as to be able to rotate relative to each other. The flange portion of one rotating body is formed with a recess that passes through the flange portion in the axial direction, and the flange portion of the other rotating body is formed with a groove corresponding to the recess.

A roller having a diameter larger than the wall thickness of the recess is fitted into the recess, one side of the outer circumference of the roller is engaged with the recess, and the other side is axially A movable overload detection panel is brought into contact with the

Further, the overload detection panel is provided with a torque spring that biases the overload detection panel along the axial direction and presses the roller into the groove.

Therefore, in such a torque limiter, when a load exceeding the set transmission limit torque value determined by the elastic force of the torque spring is applied, the roller resists the elastic force of the torque spring and separates from the groove, thereby transmitting torque. is cut off, and the rotating body on the driving side and the rotating body on the driven side rotate relative to each other.

(Problems to be Solved by the Invention) However, in such conventional torque limiters, flange portions are provided protruding from the outer peripheries of the rotating body on the driving side and the rotating body on the driven side, and there is a gap between these flange portions. Since the element for transmitting and cutting off torque, that is, the roller, is arranged, and the torque spring is arranged around the outer periphery of the rotating body on the drive side, the torque limiter itself is significantly reduced. The problem was that the diameter was increased.

In view of such conventional problems, the present invention aims to provide a torque limiter that can be made compact as a whole by housing the function for transmitting and interrupting torque inside a rotating body. purpose.

(Means for Solving the Problems) In order to achieve the above object, the present invention includes a cylindrical body connected to either a driving body or a driven body, and a cylindrical body rotatably fitted on the outside of this cylindrical body, an annular body connected to the other of the body or the driven body; a plurality of through holes penetrating the outer wall of the cylindrical body and formed in the circumferential direction; a first spherical body having a diameter larger than the wall thickness; an engaging recess formed on the inner periphery of the annular body corresponding to the through hole and into which one side of the first spherical body can be fitted; A second sphere that is movably housed and comes into contact with the first sphere at a predetermined pressure angle, and a biasing means that presses the second sphere in a direction to bring it into pressure contact with the first sphere. .

Further, it is desirable that a spring receiving member that makes point contact with the second sphere is interposed between the second sphere and the biasing means.

(Function) With the above-described structure, in the torque limiter of the present invention, the urging force of the urging means is transmitted to the first sphere through the second sphere at a predetermined pressure angle, and the first sphere is connected to the cylinder. It is pressed in the outer diameter direction along a through hole formed in the body.

Then, the first spherical body is fitted into the engagement recess of the annular body,
Torque transmission becomes possible between the cylindrical body and the annular body.

On the other hand, when a load greater than the allowable transmission torque determined by the urging force of the urging means acts between the cylindrical body and the annular body, the first sphere moves the second sphere against the urging force. While moving, the through hole is moved in the inner radial direction and removed from the engagement recess.

Therefore, in a state where the second sphere is detached from the engagement recess, the cylindrical body and the annular body are rotated relative to each other, and torque transmission is interrupted.

Further, since the first sphere and the second sphere are in contact with each other with a predetermined pressure angle, the urging force of the urging means acting on the second sphere is transmitted to each first sphere with a wedge effect. The first sphere can be pressed by converting a small urging force into a large force.

Furthermore, by changing the diameter of the second sphere with respect to the first sphere, the pressure angle between the first sphere and the second sphere is changed, and as a result, the pressing force of the first sphere is changed. The allowable transmission torque value can be adjusted by changing .

Further, the second sphere is provided between the second sphere and the biasing means.
By interposing a spring bearing member that makes point contact with the sphere,
The rolling resistance between the second sphere and the spring bearing member can be significantly reduced, and when the first sphere moves through the through hole, the first sphere and the second sphere in contact with it The transfer is carried out smoothly, and the transmission torque can be cut off smoothly.

(Example) Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

1 and 2 show a torque limiter 10 showing one embodiment of the present invention, in which FIG. 1 is a sectional side view and FIG. 2 is a sectional view taken along the line A--A in FIG.

That is, the torque limiter 10 of this embodiment has a cylindrical body 14 fixed to the outer periphery of the shaft end of the rotary drive shaft 12 as shown in the figure.
and an annular body 18 fixed to the driven body 16 side.

The annular body 18 has a pair of bearings 20 on the outer periphery of the cylindrical body 14.
, 22, and a plurality of through holes 24 are formed in the circumferential direction on the outside of the portion of the cylindrical body 14 in which the annular body 18 is fitted.

In this embodiment, as shown in FIG.
The through holes 24 may be formed at three locations at equal intervals in the circumferential direction, or may be formed at irregular intervals without necessarily being limited to equal intervals, and in this case, the number of through holes 24 may be three or more. desirable.

Furthermore, a tapered hole 26 serving as an engagement recess is formed on the inner periphery of the annular body 18 in correspondence with the through hole 24 .

First spheres 28 having a diameter larger than the wall thickness of the through hole 24 are movably fitted into the through hole 24, and the first spheres 28 are provided at one side of the cylinder 14 from which they protrude outward. can be fitted into the tapered hole 26.

On the other hand, a second sphere 30 is housed inside the cylindrical body 14 so as to be movable in the central axis direction, and this second sphere 30 is in contact with each of the plurality of first spheres 28, and at this time, The first sphere 28 and the second sphere 30 have a pressure angle α
so that they can come into contact with each other.

Further, by the second spherical body 30 contacting and being supported by the plurality of first spherical bodies 28 in this manner, the second spherical body 30 is positioned on the central axis of the cylindrical body 14 .

The pressure angle α is expressed as the angle formed between the tangent at the contact point between the first spherical body 28 and the second spherical body 30 and the central axis of the cylindrical body 14.

Further, inside the cylindrical body 14, there is a seat 32a, and the second sphere 30 extends from one side of the seat 32a (right side in FIG. 1).
The member 32 is housed in a spring bearing consisting of a shaft portion 32b extending in the opposite direction.

The other side (left side in FIG. 1) of the spring receiver of the member 32 is in point contact with the second sphere 30, and this receiver is in contact with one side of the seat 32a and the end of the cylinder 14. A compression spring 34 as a biasing means is compressed between the two.

Therefore, the biasing force of the compression spring 34 acts as a load that presses the second sphere 30 to the left in FIG. 1 via the spring bearing member 32.

A locking tool 36 of the compression spring 34 is screwed onto the inner circumference of one end of the cylinder 14 to which one end of the compression spring 34 is locked, and the locking tool 36 is rotated to release the cylinder 1.
By changing the axial position relative to the compression spring 4, the biasing force of the compression spring 34 can be finely adjusted.

The adjusted position of the locking tool 36 can be fixed with a lock nut 38.

Further, one end of the shaft portion 32b of the member 32 (right end in FIG. 1) of the spring receiver protrudes through the center of the locking tool 36, and the end surface of this protruding side is provided with a spring receiver. is member 32
An allowable torque sensor 40 is provided for detecting the allowable transmission torque from the amount of movement of the compression spring 34, that is, the adjustment amount of the biasing force of the compression spring 34.

With the above configuration, in the torque limiter 10 of this embodiment, the spring bearing is configured such that the biasing force of the compression spring 34 transmitted to the second sphere 30 via the member 32 is adjusted to a predetermined pressure angle α.
is transmitted to the first sphere 28.

Then, the first spherical body 28 is pushed in the through hole 24 toward the outside of the cylindrical body 14 and fitted into the tapered hole 26 of the annular body 18, and is inserted between the cylindrical body 14 and the annular body 18, that is, the rotational drive shaft. 12 and the driven body 16 becomes capable of transmitting torque.

At this time, the allowable amount of torque transmission between the cylindrical body 14 and the annular body 18 is such that the first spherical body 28 is
The force required to keep the first sphere 28 in the fitted state is determined by the load that presses the first sphere 28 outward from the cylindrical body 14, and in other words, it is determined by the biasing force of the compression spring 34.

On the other hand, when a load greater than the allowable transmission torque determined by the biasing force of the compression spring 34 is applied between the cylindrical body 14 and the annular body 18, the first spherical body 28 is pushed out of the Tapered hole 26. and moves inward of the cylindrical body 14 within the through hole 24.

When the first sphere 28 is removed from the tapered hole 26, the cylindrical body 14 and the annular body 18 are rotated relative to each other, and torque transmission between the rotary drive shaft 12 and the driven body 16 is interrupted. Ru.

Note that when the first sphere 28 is removed from the tapered hole 26, the first sphere 28 presses the second sphere 30, so that the second sphere 30 resists the urging force of the compression spring 34 and springs. The receiver is moved to the right in FIG. 1 together with the member 32.

By the way, when the torque transmission is interrupted in this way, the first sphere 28 is moved while being transferred within the through hole 26, and the rotation of the first sphere 28 at this time is caused by the second sphere 30 that is in contact with it. This is transmitted and attempts to rotate this second sphere 30.

At this time, the second sphere 30 is directly connected to the compression spring 3.
4, the spring bearing member 32 is interposed between the second sphere 30 and the compression spring 34, and the second sphere 30 is in point contact with the seat 32a. The rotational resistance of this second sphere 30 is significantly reduced.

Therefore, as the first sphere 28 rotates, the second sphere 30
The first sphere 28 is also rotated smoothly, and the movement of the first sphere 28, that is, its removal from the tapered hole 26, is performed smoothly, and torque transmission can be accurately interrupted at a predetermined setting value.

Furthermore, in this embodiment, when the second sphere 30 presses the first sphere 26 in the torque transmission state, the first sphere 28 and the second sphere 30 have a predetermined pressure angle α. Since they are in contact with each other, the biasing force of the compression spring 34 acting on the second spheres 30 is transferred to each of the first spheres 28.
can be transmitted through a wedge action.

Therefore, the biasing force of the compression spring 34 can be converted into a large force and transmitted to the first sphere 28. Therefore, it is possible to reduce the spring constant of the compression spring 34 and reduce its wire diameter. can.

In addition, by changing the diameter of the second sphere 30 with respect to the first sphere 28, the pressure angle α can be changed, and as a result, the pressure of the first sphere 28 against the urging force of the compression spring 34 can be changed. By varying the pressure, the allowable transmitted torque value can be adjusted.

Therefore, by preparing a plurality of second spheres 30 having different diameters and simply replacing the second spheres 30, it is possible to easily set a wide range of allowable torque cutoff values.

Furthermore, since the second sphere 30 is supported by the plurality of first spheres 28 and positioned on the central axis, the second sphere 30
Contact resistance between the inner side of the cylinder body 14 and the inner side of the cylinder body 14 can be eliminated, and the torque cutoff function can be performed more stably.

By the way, in the torque limiter 10, the first sphere 2
Since the biasing force of the compression spring 34 is always acting on the first sphere 28, when the cause of the overload is removed, the first sphere 28 is fitted into the tapered hole 26 again and returns to the torque transmitting state.

In addition, when this torque transmission returns, in this embodiment, the through holes 24 into which the first sphere 28 is fitted are formed at equal intervals in the circumferential direction of the cylindrical body 14, and accordingly, the tapered holes 26 are also formed in the annular body 18. Since they are formed at equal intervals, the first spheres 28 are fitted into all the tapered holes 26 at the same time, and the return point per rotation is equal to the number of through holes 24, that is, 3 m in this embodiment. present, and rapid torque transmission recovery takes place.

Incidentally, if the through holes 24 are provided at uneven intervals,
The first sphere 28 can be inserted when the through hole 24 and the tapered hole 26, which have been formed correspondingly in advance, coincide with each other, and there is only one return point per rotation.

As described above, the torque limiter 10 of this embodiment includes each functional component for limiting torque transmission, that is, the first sphere 28. Second sphere 30. Since the spring bearing member 32, compression spring 34, etc. can be housed inside the cylindrical body 14, the torque limiter 10 can be configured to have a small diameter as a whole, thereby achieving significant downsizing.

(Effects of the Invention) As explained above, the torque limiter according to claim 1 of the present invention includes a cylinder connected to either the driving body or the driven body, and a rotatable cylinder connected to the outside of the cylinder. an annular body that is fitted and connected to the other of the driving body or the driven body, each component for limiting torque transmission within the cylinder, that is, fitting into and detachment from an engagement recess of the annular body; A first sphere that transmits and interrupts torque, a second sphere that presses the first sphere in the direction of fitting into the engagement recess, and a biasing means that generates a biasing force on the second sphere are housed, so Therefore, it is possible to provide a compact torque limiter that can be downsized.

Further, since the first sphere and the second sphere are in contact with each other at a predetermined pressure angle, a wedge action is exerted between the first sphere and the second sphere, and a small The biasing force can be converted into a large force and transmitted to the first sphere.

Furthermore, since the pressure angle can be changed by changing the diameter of the second sphere with respect to the first sphere, the allowable transmission torque value can be easily adjusted by simply replacing the second sphere. be able to.

Moreover, in claim 2 of the present invention, a spring receiving member that makes point contact with the second sphere is interposed between the second sphere and the urging means, so that the first sphere can be inserted into the through hole. The transfer of the first sphere and the second sphere is performed smoothly when moving the sphere, and the transmission torque can be cut off accurately at a preset value.
It has various excellent effects.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional side view showing an embodiment of a torque limiter according to the present invention, and FIG. 2 is a cross-sectional view taken along the line A--A in FIG. 10... Torque limiter 12... Rotation drive shaft 14... Cylindrical body 16... Driven body 18... Annular body 24... Through hole 26... Taper hole (engaging recess) 28 ...First sphere 30...Second sphere 32...Spring receiver is member 34...Compression spring (biasing means) Fig. 1 Fig. 2

Claims (2)

[Claims] (1) A cylindrical body connected to one of the driving body or the driven body, an annular body rotatably fitted to the outer periphery of the cylindrical body and connected to the other of the driving body or the driven body, and the cylindrical body a first spherical body movably fitted into each of the through holes and having a diameter larger than the wall thickness of the through hole; and an inner periphery of the annular body. an engaging recess that is formed to correspond to each of the through holes and into which one side portion of the first sphere can be fitted; a second spherical body that presses the second spherical body against the first spherical body;
A torque limiter characterized by being equipped with. (2) The torque limiter according to claim 1, characterized in that a spring bearing member that makes point contact with the second sphere is interposed between the second sphere and the urging means.