JP2598421B2 - Torque limiter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention is mounted between a rotary drive shaft and a driven shaft, and usually transmits the rotational motion of the drive shaft to the driven shaft, and has one of the shafts. The present invention relates to a torque limiter that functions to prevent accidents such as breakage of a machine or perform torque control by releasing the transmission when an overload exceeding a predetermined limit torque is applied.

<< Conventional Technology >> As this kind of torque limiter, for example,
What is described in -21893 is known. In this apparatus, a driving side and a driven side rotating body, each of which is a cylindrical boss member having a flange portion, are fixed to the outer periphery of a driving shaft and a driven shaft disposed coaxially so as to face each other. A concave portion is formed in the flange portion of the rotating member in the axial direction, and a concave groove is provided in the flange portion of the other rotating member, and a rolling element (roller) is engaged with the concave portion and the concave groove. In addition, the rolling element is pressed against the groove by the elastic force of the torque spring. One end of the torque spring is in contact with the rolling element via a thrust washer, and the other end is in contact with a pressure nut screwed to the boss of one of the rotating bodies and is compressed and interposed therebetween. The elastic pressure can be arbitrarily set by adjusting the tightening amount of the pressure nut.

Therefore, in this torque limiter, when a load equal to or greater than the limit torque value set by adjusting the spring pressure acts, the rolling element separates from the groove against the elastic pressure of the torque spring, thereby interrupting the transmission of torque. Thus, the drive shaft and the driven shaft rotate relatively.

<< Problems to be Solved by the Invention >> However, in the prior art in which the elastic force of the torque spring is adjusted by the amount of tightening of the pressure nut, and thereby the set transmission limit torque value can be arbitrarily set. Since the set transmission limit torque value cannot be changed during operation of the equipment, the required transmission torque at the time of start / stop with sudden acceleration / deceleration that becomes a large value compared to the normal torque value when using steady rotation is In addition, the transmission limit torque value had to be set.

For this reason, there has been a problem that transmission of torque cannot be interrupted by detecting a slight abnormality during steady rotation operation.

In addition, torque springs have a certain degree of variation in their elastic coefficients due to material errors in the materials themselves and shape and dimension errors during molding.Therefore, the torque limiter after assembly has its maximum transmission torque value for each product. There is also a problem that variations easily occur and it is difficult to accurately adjust the set transmission limit torque value.

On the other hand, an overload safety device for industrial machinery disclosed in Japanese Utility Model Laid-Open No. 57-85650 is known in which the transmission torque is adjusted by a fluid pressurizing means without using the torque spring.

In this overload safety device, a spline shaft is formed at a shaft end of a drive shaft protruding from the industrial machine main body, and a drive shaft movable in the axial direction is spline-fitted to the spline shaft. The drive shaft is rotatably supported by a fixed flange ring fixed to the main body of the industrial machine while allowing axial movement and forming an enlarged flange portion at the end of the drive shaft protruding from the fixed flange ring. A driven shaft having a flange portion facing the flange portion is coaxially arranged, and a steel ball for transmitting torque is interposed between opposing surfaces of the drive shaft flange and the driven shaft flange. The engagement recesses formed on both of the flange portions are engaged with each other, and one engagement recess is formed in a conical shape so that the steel ball can be detached therefrom. An intermediate ring forming a closed pressurized chamber to which a pressure fluid is supplied to the back surface side is slidably fitted in the axial direction, and this intermediate ring is integrally formed on the outer peripheral edge of the flange portion of the driven shaft. The pressurizing chamber is configured to supply a working fluid having a predetermined pressure from a supply passage formed in the drive shaft to the pressurizing chamber to press the flange portion of the drive shaft against the flange portion of the driven shaft. In this case, the working fluid that has been pressed at a predetermined pressure flows backward, and the drive shaft retreats in the axial direction, so that torque transmission by the steel balls is interrupted.

However, in this overload safety device, the pressurizing chamber is defined by the flange of the drive shaft and the intermediate ring integrally fixed to the driven shaft. When the drive shaft is shut off, a relative rotation difference is generated between the drive shaft and the intermediate ring, so that the seal member that seals and seals the drive shaft and the intermediate ring is easily damaged, and is inferior in durability. In addition, there is a problem that it is difficult to ensure the sealing performance.

The present invention has been made in view of the above circumstances,
The purpose is to make it possible to vary the set transmission limit torque value even during operation of the equipment, to easily and reliably adjust the set transmission limit torque value, and to minimize variations among products. And to provide a torque limiter which is excellent in durability.

<< Means for Solving the Problems >> In order to solve the above problems, the present invention provides a driving-side rotating body and a driven-side rotating body coaxially opposed to each other,
Either one of the rotating bodies is provided with a rolling element which can be retracted toward the other rotating body, and the other rotating body is provided with a concave portion with which the rolling element is engaged. Is provided with a fluid pressurizing means attached to the rotating body and pressing the rolling body against the other rotating body at a predetermined pressure, and the fluid pressurizing means operates through a supply passage formed in the one rotating body. A pressure source for supplying the fluid was connected via a pressure adjusting means.

<Operation> According to the present invention having the above-described configuration, the limit transmission torque value between the rotating body on the driving side and the rotating body on the driven side is determined by the pressure of the fluid supplied to the fluid pressurizing means. The pressure of the fluid can be arbitrarily set by the pressure adjusting means. Also, since the fluid pressurizing means is attached to one of the rotating bodies and presses the rolling bodies while rotating integrally, even when torque transmission is interrupted, there is no member that causes a rotational difference between the two, and the sealing performance is secured. It is easy to do and has excellent durability.

<< Example >> Hereinafter, a preferred example of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a side sectional view of an embodiment of a torque limiter according to the present invention, and FIG. 2 is a sectional view taken along line II-II in FIG. In the figure, 2 is a rotary drive shaft, 4 is a rotating body on the driving side, and 6 is a rotating body on the driven side.

The rotating body 4 on the driving side is a cylindrical boss member 8 fixed to the shaft end of the driving shaft 2 and the boss member 8 has a central portion whose diameter is increased radially outward. Flange part 10
Are formed. Further, a recess 12 is formed in the flange portion 10 on its outer peripheral side so as to penetrate the flange portion 10 in the axial direction.

The driven rotating body 6 is an annular boss member 14 which is rotatably fitted on the outer peripheral side of one end of the driving side boss member 8 so as to be allowed to rotate relative to the one end portion. 14
The flange 10 of the drive-side boss member 8
A flange portion 16 is formed so as to face radially outwardly. A concave groove 18 is formed in the flange portion 16 so as to correspond to the concave portion 12 formed in the flange portion 10 of the boss member 8 on the driving side. The driven side boss member 14
Is locked by a nut 20 screwed to one end of the boss member 8 on the driving side, and the boss member 14 on the driven side and the nut
20, the drive side boss member 8 to the drive side flange 10
A bearing 22 is interposed between each of them.

The recess 12 formed in the flange portion 10 of the driving-side boss member 8 and the recessed groove 18 formed in the flange portion 16 of the driven-side boss member 14 are engaged with each other and serve as rolling elements. A roller 24 is fitted. A part of the outer periphery of the roller 24 protrudes from the recess 12 of the driving-side flange portion 10 to the rear surface side thereof, and a thrust washer 26 abuts the protruding portion.

The thrust washer 26 has the roller 24
A fluid pressurizing means 28 is provided to press the driven side against the flange 16 on the driven side. This fluid pressurizing means 28 is an annular pressure chamber screwed and fixed to the outer peripheral side of the other end of the boss member 8 on the driving side.
A cylinder 32 having a cylinder 30 and an annular piston 34 fitted and slidably fitted in the pressure chamber 30 along the axial direction, the piston 34 being in contact with the thrust washer 26. ing. The piston 34 has a piston ring for sealing a sliding portion between the piston 32 and the cylinder 32.
36 are fitted.

The rotary drive shaft 2 is provided with the cylinder
A supply path 38a for supplying a working fluid into the pressure chamber 30 of 32
Are drilled from the shaft end 2a on the drive source side.
38a is the drive shaft 2, the drive side boss member 8 and the cylinder 32.
The pressure chamber 3 is formed by a supply passage 38b formed by drilling
Communicated with 0. Further, between the drive shaft 2 and the boss member 8 on the drive side and between the boss member 8 and the cylinder 32, sealing properties are provided on both sides in the axial direction adjacent to the supply passage 38b formed in the radial direction. A seal ring 40 is provided to secure the pressure.

A supply pipe 42 for supplying a working fluid to a supply passage 38a formed in the shaft core while permitting the rotation of the rotation drive shaft 2 is connected to the shaft end 2a of the rotation drive shaft 2. tube
Reference numeral 42 is connected to a pressure source 46 via a pressure regulator 44.
Therefore, in this case, although not shown, a motor or the like as a power source is connected to the rotary drive shaft 2 via a speed reducer or the like and provided on the side thereof.

Therefore, in such a torque limiter,
The set transmission limit torque value is determined by the pressure value of the working fluid supplied into the pressure chamber 30 of the cylinder 32, and the pressure value of the working fluid is arbitrarily adjusted by the pressure regulator 44. When the load from one of the rotating bodies 4 or 6 exceeds a set transmission limit torque value determined by the pressing force of the fluid pressurizing means 28 during the operation of the apparatus and at the time of starting and stopping the apparatus, the roller 24 serving as a rolling element is activated. It is disengaged from the groove 18 formed in the flange 16 of the rotating body 6 on the driven side against the pressing force of the fluid pressurizing means 28 and is pushed back, whereby the torque transmission between the driving side and the driven side is cut off. They rotate relative to each other.

By the way, since the setting of the transmission limit torque value is performed by the pressure regulator 44, the setting is easy and reliable, and the error of the set transmission limit torque value generated in the product after the assembly is completed can be extremely small. In other words, variations in errors between products can be suppressed as much as possible.

In addition, the set value can be arbitrarily varied even during operation, and therefore, at the time of starting or stopping when a large load is applied compared with the case of the steady rotation operation, the setting value is set in accordance with the required transmission torque. The transmission limit torque value is increased, and during a steady rotation operation in which a very large load is not applied, the set transmission limit torque value can be reduced in accordance with the transmission torque value required to maintain the rotation. As a result, transmission of torque can be interrupted by detecting a slight abnormality during steady-state rotation operation, and the reliability and durability of the device can be improved as much as possible.

Further, a cylinder 32 having an annular pressure chamber 30 screwed and fixed to the outer peripheral side on the other end side of the boss member 8 on the driving side is slidably fitted in the pressure chamber 30 along the axial direction. The fluid pressurizing means 28 including the inserted annular piston 34 is attached to the rotary drive shaft 2 of one of the rotating bodies and presses the roller 24 of the rolling body while rotating integrally, so that torque transmission is interrupted. In this case, there is no rotation difference between the cylinder 32 and the piston 30, and the piston ring 36 for sealing the sliding portion between the piston 34 and the cylinder 32 is hardly damaged and has excellent durability. Moreover, it is easy to ensure the sealing performance.

3 and 4 each show a modified embodiment.

In the first modified embodiment shown in FIG. 3, a compression coil spring 48 is disposed on the circumference of a concentric circle at an appropriate interval between the piston 34 and the flange portion 10 of the boss member 8 on the driving side. And the elasticity of the compression coil spring 48 is the piston 34
Is set to be equal to the frictional resistance between the cylinder and the cylinder 32.

Therefore, according to the first modified embodiment, it is possible to eliminate the influence of frictional resistance when the piston 34 is pushed back into the cylinder 32.

In the second modified embodiment shown in FIG. 4, a compression coil spring 50 for urging the piston 34 to protrude is interposed in the pressure chamber 30 of the cylinder 32. It is intended to always maintain a certain transmission torque by force.

Therefore, according to the second modified embodiment, the set transmission limit torque value during the steady rotation operation is determined by the compression coil spring.
It can be obtained by a resilience of 50, and the set transmission limit torque value can be increased by the fluid pressurizing means 28 only at the time of starting and stopping.

In each of the above-described embodiments shown in FIGS. 1 and 3 to 4, as shown in FIGS. 5 to 7, the cylinder 32a of the fluid pressurizing means 28 does not have a partition on the inner peripheral side. The pressure chamber 30 is formed by the cylinder 32a and the boss member 8 on the driving side.
And the cylinder 32a. In this case, the cylinder 32a is locked to the boss member 8 by a snap ring 52 or the like.

Further, in the embodiments shown in the respective drawings, the driving body rotating body 4 and the driven side rotating body 6 are engaged with each other by rolling elements including rollers 24, but steel balls are used. The rolling elements may be made to engage with each other.

That is, as shown in FIG. 8, for example, the flange portion 10a of the rotating body 4 on the driving side is formed so that its outer peripheral portion is thick, and the thick portion is provided with a recess 12a for accommodating the steel ball 56. . The driven-side rotator 6 is formed in a cylindrical shape, and is provided so as to cover the outer peripheral side of the driving-side rotator 4.
a is formed. The inner peripheral surface side of the thick portion is formed to be inclined, and a part of the steel ball 56 projects from the inclined surface. An annular thrust washer 26a having a wedge-shaped cross section is brought into contact with the projecting portion of the steel ball 56.
6a is pressed in the axial direction by the piston 34 of the fluid pressurizing means 28, and the steel ball 56 is pressed in the radial direction via the thrust washer 26a so as to be freely retractable and pressed against the rotating body 6 on the driven side.

The fluid pressurizing means 28 is separately supported from a fixed system, and the boss member 8 on the driving side and the thrust washer 26 (or
26a), by allowing the rotation thereof, the supply pipe 42 can be directly connected to the cylinder 32 of the fluid pressurizing means 28, and the fluid pressurizing means 28 and the supply pipe 42
And the connecting portion structure can be simplified.

<Effects> In summary, according to the present invention, a rolling element that projects from one rotating body toward the other rotating body and engages with both of them to transmit torque from a driving side to a driven side is provided. ,
The working fluid supplied to the fluid pressurizing means is made to be able to be arbitrarily adjusted by the pressure regulator, so that the set transmission limit torque value can be easily adjusted. In addition, it is possible to perform the operation reliably and to make the set value error for each product as small as possible so as to achieve the uniformity.

In addition, since the set transmission limit torque value can be arbitrarily changed even during operation of the device, when starting or stopping when a large load is applied compared to the normal rotation operation, the set transmission limit torque value is set in accordance with the required transmission torque. It is possible to easily increase the limit torque value and reduce the set transmission limit torque value in accordance with the transmission torque value required to maintain the rotation during steady-state rotation operation in which a very large load is not applied. As a result, transmission of torque can be interrupted by detecting a slight abnormality during steady-state rotation operation, and the reliability and durability of the device can be improved as much as possible.

Also, since the fluid pressurizing means is attached to one of the rotating bodies and presses the rolling bodies while rotating integrally, even when torque transmission is interrupted, there is no member that causes a rotational difference between the two, and the sealing performance is secured. It is easy to do and has excellent durability.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing one embodiment of a torque limiter according to the present invention, FIG. 2 is a sectional view taken along line II-II in FIG.
FIG. 3 is a side sectional view showing a first modified embodiment, FIG. 4 is a side sectional view showing a second modified embodiment, and FIGS. 5 to 7 are FIGS. 1 and 3 to 3 respectively. FIG. 4 is a side sectional view showing a modified example of the cylinder portion of each embodiment shown in FIG. 4, and FIG. 8 is a side sectional view showing a modified example of the torque transmitting portion structure. 4 ... Rotating body on the driving side 6 ... Rotating body on the driven side 24 ... Roller that is a rolling element 28 ... Fluid pressurizing means 44 ... Pressure regulator 46 ... Pressure source 56 ... Steel ball as a rolling element

Claims (1)

(57) [Claims] A rotating body on the driving side and a rotating body on the driven side are provided coaxially and opposed to each other, and one of the rotating bodies is a rolling body which can be moved toward and out of the other rotating body. And the other rotating body is provided with a concave portion with which the rolling element is engaged, and the one rotating body is attached to the rotating body and presses the rolling body against the other rotating body at a predetermined pressure. A torque source for supplying a working fluid through a supply passage formed in the one of the rotary members via a pressure adjusting means.