JP7076786B2 - Gear mechanism with torque limiter - Google Patents

Description

The present invention relates to a gear mechanism with a torque limiter, and in particular, the number of parts that rotate idle when a certain amount of torque is input is reduced as compared with the conventional case, so that stable torque limiter operation can be obtained regardless of the temperature rise and fall. Regarding new improvements to.

As a gear reducer with a torque limiter of this type that has been conventionally used, for example, "Gear reducer with a torque limiter" of Patent Document 1 can be mentioned.
That is, in FIGS. 4 and 5, the rotation of the motor shaft pinion 10 is transmitted to the input gear 21. The rotation of the input gear 21 is transmitted to the sliding plate 61 via the friction plate 62 as a friction clutch, and the first pinion shaft 20 rotates together with the sliding plate 61. The rotation of the first pinion shaft 20 causes the output gear 22 to rotate, and the input gear 31 that meshes with the output gear 22 rotates. The rotation of the input gear 31 is transmitted to the second pinion shaft 30, and the output gear 32 rotates together with the second pinion shaft 30. Then, the input gear 41 that meshes with the output gear 32 rotates, and the output shaft 40 of the speed reducer that supports the input gear 41 rotates.
Next, when a load torque of a certain value or more is applied to the reducer output shaft, the disc type friction clutch slides.
When the load torque is transmitted to the sliding plate 61, slippage occurs between the sliding plate 61 and the friction plate 62, and the torque limiter mechanism 60 operates. The sliding of the input gear 21 and the pinion shaft 20 when the torque limiter mechanism 60 is operated is handled by the sliding mechanism by the sliding bearings 23 and 24 arranged on the inner peripheral surface side of the input gear 21, and the load torque is transmitted. Can be prevented.

Japanese Unexamined Patent Publication No. 2006-70961

Since the conventional gear mechanism with a torque limiter is configured as described above, the following problems exist.
That is, when the input torque exceeds a certain level, the rotating part is not limited to the gear, and when the temperature is high or low, the characteristics of the sliding parts of the slide bearing change and the sliding torque is not constant. , The gear on the output side (output shaft 40) was also supposed to rotate.
Therefore, when an excessive input is input to the motor shaft pinion, which is an input shaft, the output shaft 40 is supposed to rotate.

The present invention has been made to solve the above problems, and in particular, when a certain torque or more is input, the number of rotating parts is smaller than before, and it is stable regardless of the temperature rise and fall. The purpose is to obtain the torque limiter operation.

The gear mechanism with a torque limiter according to the present invention is provided in the first gear fixed to the first keyway on one end side of the shaft via the first key and in the first notch on the inner surface of the first gear. , A first plate having a plurality of detent holes, a ball provided in a through hole of a second gear provided adjacent to the first gear, and a second gear that can move directly in the second keyway of the shaft. The two plates, the second gear arranged between the first and second plates, the ring-shaped groove formed on the inner surface of the second plate and in contact with one surface of the ball in contact with the detent hole, and the shaft. A lock nut screwed to the other end side of the shaft, a lock washer provided at the outer peripheral position of the shaft and inside the lock nut, and an elastic body provided between the lock washer and the second plate. The ball is sandwiched between the detent hole and the ring-shaped groove, and by rotating the lock nut, the second plate is urged toward the ball side and an input to the first gear is provided. When the torque exceeds a certain level, the rotating parts are referred to as the second gear by preventing the plates in contact with the second gear that slides from rotating with respect to the shaft by the first and second keys. The ball is configured so that the force of the elastic body can be transmitted to the second plate, the ball, and the first plate, and the force for suppressing the second gear in the axial direction is not applied. The elastic body is composed of a countersunk spring.

Since the gear mechanism with a torque limiter according to the present invention is configured as described above, the following effects can be obtained.
That is, instead of using a sliding mechanism that changes the frictional state between high temperature and low temperature as in the past, when the input torque exceeds a certain level, it is held between the detent hole 75 and the ring-shaped groove 85. Since the ball 6 and the second gear 80 rotate and slide, the first plate 74 and the second plate 74a that are in contact with the sliding second gear 80 are keyed regardless of the change in downward movement due to the ambient temperature. By preventing rotation with respect to the shaft 1 by 71 and 7A, the parts that rotate at such times are limited to the ball 6 inserted in the through hole 100 of the second gear 80 with the second gear 80. , The sliding torque due to the upward and downward movement of the temperature can be kept almost constant.
Further, the force of the elastic body 91 is transmitted to the second plate 74a, the ball 6 and the first plate 74, and it is not necessary to apply the urging force in the axial direction A to the second gear 80 , so that a stable sliding torque can be obtained. ..
Further, since the elastic body 91 is formed by a spring or a disc spring, the restoring force is excellent, and the limit accuracy as a torque limiter can be maintained.

It is sectional drawing which shows the gear mechanism with a torque limiter by this invention. FIG. 1 is a schematic cross-sectional view taken along the line AA'in FIG. It is a schematic cross-sectional view of BB'of FIG. It is sectional drawing which shows the gear mechanism with a conventional torque limiter. It is an enlarged side view which shows the torque limiter mechanism of FIG.

The gear mechanism with a torque limiter according to the present invention reduces the number of rotating parts when a certain torque or more is input, and obtains a stable torque limiter operation regardless of the vertical movement of the temperature.

Hereinafter, a preferred embodiment of the gear mechanism with a torque limiter according to the present invention will be described with reference to the drawings.
The same or equivalent parts as those of the conventional example will be described with the same reference numerals.
In FIG. 1, what is indicated by reference numeral 1 is a shaft provided at a predetermined position, and the first key 71 is inside the first key groove 74aA inside the flange portion 70 formed on the outer periphery of the shaft 1. A first gear 31 is inserted on the outer periphery of the shaft 1 so as to be engaged with the shaft 1.

A notch 90 made of a ring-shaped recess 73 is formed in the inner end surface 71a of the first gear 31, and a ring-shaped first plate 74 having a plurality of detent holes 75 is internally provided in the ring-shaped recess 73. There is.
The detent holes 75 formed in the first plate 74 are formed at equal intervals along the peripheral edge 74a of the first plate 74.
A first key groove 74aA for inserting the first key 71 is formed in a part of the inner circumference of the first plate 74.
The first key 71 is engaged with the first key groove 74aA formed on the outer periphery of the shaft 1, so that when the shaft 1 rotates, the first key 71 is passed through the first key 71. The plate 74 and the first gear 31 are configured to rotate together.

A second gear 80 is arranged on the shaft 1 at a position adjacent to the first plate 74 in a state of being adjacent to the first plate 74.
A second notch 81 formed in a ring shape is formed on the side portion 80a of the second gear 80, and a second key groove is formed on a part of the surface of the shaft 1 so as to communicate with the second notch 81. 82 is formed.

The side portion 80a, which is the inner surface of the second plate 74a, is configured so that the outer surface of the ball 6 can rotate or slide to move in the annular groove 85 of FIG.
Further, the lower portion of the second plate 74a is configured such that the second key 7A located in the second key groove 82 can move along the axial direction A.
The torque is generated by the above-mentioned first gear 31, first plate 74, detent hole 75, ball 6, second gear 80, second plate 74a, ring-shaped groove 85, elastic body 91, lock washer 88A, and lock nut 88. It constitutes a limiter mechanism 60.

A locknut 88 is screwed into the outer peripheral screw 87 formed on the outer periphery on the other end 1B side opposite to the tip 1A of the shaft 1, and the protrusion 88a of the locknut 88 is the second key. Engaging in the groove 82, the protrusion 88a is configured to be linearly movable along the direction of the arrow A independently of the shaft 1.
An elastic body 91 made of any of disc springs, springs, rubbers, etc. is disposed between the lock washer 88A having the protrusion 88a and the second plate 74a, so that the lock nut 88 is tightened. When the second plate 74a strongly urges the ball 6 into each of the detent holes 75, the torque limiter that slides or rotates on the ring-shaped groove 85 smoothly operates. It becomes difficult to obtain.

Next, the operation of the gear mechanism with a torque limiter according to the present invention will be described.
In FIGS. 1 to 3 described above, when the input torque to the first gear 31 on the input side is constant or less, the torque of the first gear 31 is the ball 6 due to the input from each part input device (not shown). The second gear 80 on the output side is also transmitted through the detent hole 75 and the ring-shaped groove 85 at substantially the same rotation.

Under the above-mentioned state, the plates 74,74a in contact with the second gear 80, which slides when the input torque to the first gear 31 exceeds a certain level, are pressed by the first and second keys 71,7A. By preventing the shaft 1 from rotating, only the second gear 80 and the ball 6 are the parts that rotate at this time.

Further, the repulsive force of the elastic body 91 can be transmitted to the second plate 74a, the ball 6, and the first plate 74, and is configured so as not to apply a force to suppress the second gear 80 in the axial direction A. ing.
As described above, the elastic body 91 was optimally configured to use various disc springs.
Further, depending on the tightening condition of the locknut 88, it is possible to freely set any one of the gears 31 and 80 to rotate freely with respect to the input as the torque limiter.

In the present invention, the gear mechanism with a torque limiter has only one gear and a ball as parts to rotate when the torque limit state is reached, and the sliding torque is constant regardless of the temperature change. Therefore, the torque limiter is used. It is possible to extend the life as a.

1A One end 1B Another end 6 Ball 7A 2nd key 31 1st gear 60 Torque limiter mechanism 70 Brim part 71 1st key 71a Inner end surface 73 Ring-shaped recess 74 1st plate 74a 2nd plate 74aA 1st key groove 75 Detent hole 80th 2 gears (output side)
80a Inner part 81 2nd notch 82 2nd key groove 85 Ring groove 87 Outer peripheral screw 88 Locknut 88A Lock washer 88a Protrusion 90 1st notch 91 Elastic body (spring, disc spring, etc.)
100 Through hole A Axial direction

Claims (2)

The first gear (31) fixed to the first keyway (74aA) on the one end (1A) side of the shaft (1) via the first key (71), and the inner surface of the first gear (31). A first plate (74) provided in the first notch (90) and having a plurality of detent holes (75), and a second gear (80) provided adjacent to the first gear (31). The ball (6) provided in the through hole (100), the second plate (74a) that can move directly in the second keyway (82) of the shaft (1), and the first and second plates (the first and second plates). The second gear (80) disposed between 74,74a) and one surface of the ball (6) formed on the inner surface of the second plate (74a) and in contact with the detent hole (75) are in contact with each other. A ring-shaped groove (85), a lock nut (88) screwed to the other end (1B) side of the shaft (1), and an outer peripheral position of the shaft (1) and inside the lock nut (88). A rock washer (88A) provided and an elastic body (91) provided between the lock washer (88A) and the second plate (74a) are provided.
The ball (6) is sandwiched between the detent hole (75) and the annular groove (85), and by rotating the lock nut (88), the second plate (74a) becomes the ball (74a). 6) When the input torque to the first gear (31) is urged to the side and exceeds a certain level, the plates (74,74a) in contact with the sliding second gear (80) are first placed on the first gear. By preventing rotation with respect to the shaft (1) by the second key (71,7A), the rotating parts are the second gear (80) and the ball (6), and the elastic body (91). ) Can be transmitted to the second plate (74a), the ball (6) and the first plate (74), and the second gear (80) should not be subjected to an axially restraining force (A). A gear mechanism with a torque limiter, which is characterized by being configured in. The gear mechanism with a torque limiter according to claim 1 , wherein the elastic body (91) is made of a disc spring.

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