Torque limiting device of ball type harmonic reducer

Abstract

The torque limiting device of the ball type harmonic reducer comprises a flexible gear, an output flange, a ball, an elastic piece, a flexible gear pressing plate and a spring flange. A flexible gear groove is formed in the end face of the flexible gear, a spring flange groove is formed in the opposite spring flange face, and the balls are clamped in the flexible gear groove and the spring flange groove. During normal operation, the elastic piece compresses the ball, so that the flexible gear and the output flange are combined into a whole, and the flexible gear transmits torque to the output flange through the ball; when the load torque is larger than the limiting torque, axial force generated by the balls pushes the elastic pieces to be compressed, the balls are made to be disengaged from the grooves of the flexible gear, then rotation slipping is generated between the flexible gear and the output flange, and torque transmission is interrupted. As the torque limiting device is integrated in the harmonic reducer, the end face space of the flexible gear and the end face space of the output flange are fully utilized, the structure is compact, and the size is small.

Description

Technical Field

[0001] The present invention relates to a torque limiting device for a harmonic reducer. Background Art

[0002] One end of a harmonic reducer is connected to a motor, and the other end is connected to a load device, mainly to reduce the rotational speed of the output shaft and increase the output torque.

[0003] In daily use, the load of the harmonic reducer often gets stuck due to mechanical failures or is suddenly impacted externally. Since the harmonic reducer is a precision transmission component, especially the tooth profile of the flexspline and the thin wall of the flexspline can withstand relatively poor rigidity and are easily damaged by the impact force of the load.

[0004] The existing solutions are to additionally provide a torque limiter between the reducer and the load, including a spring type and a friction plate type torque limiter. However, they all have the following deficiencies: 1. The axial length of the harmonic reducer is increased, resulting in a bulky overall transmission mechanism. Since the application fields of harmonic reducers are mostly fields with high space requirements, such as industrial robots, the volume of the harmonic reducer cannot be too large, especially the axial length.

[0005] 2. The number of connection parts increases, resulting in a larger transmission clearance and affecting the precision.

[0006] 3. The structure is complex, and installation and disassembly are difficult. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to overcome the above-mentioned defects of the prior art and provide a ball-type torque limiting device for a harmonic reducer, which is integrated inside the harmonic reducer and can protect the precision components inside the harmonic reducer from large load impacts without increasing the axial distance.

[0008] The technical solution adopted by the present invention to solve the above technical problem is as follows: The ball-type torque limiting device for a harmonic reducer includes a flexspline, an output flange, balls, an elastic member, a flexspline pressing plate, and a spring flange; a flexspline groove is provided on the end face of the flexspline, and a spring flange groove is provided on the opposite spring flange surface; the balls are clamped in the flexspline groove and the spring flange groove; during normal operation, the elastic member presses the balls to integrate the flexspline and the output flange, and the flexspline transmits torque to the output flange through the balls; when the load torque is greater than the limiting torque, the axial force generated by the balls pushes the elastic member to compress, causing the balls to disengage from the flexspline groove, and then rotational slippage occurs between the flexspline and the output flange, interrupting torque transmission.

[0009] Preferably, a cylindrical shaft is provided at the center of the output flange, an internal space is provided outside the cylindrical shaft, a set of elastic members are placed in the internal space of the output flange, a groove is formed on the end face of the flexspline, and the flexspline is sleeved on the cylindrical shaft. The flexspline pressing plate and the cylindrical shaft on the output flange are fastened to limit the flexspline axially.

[0010] The torque limiting device of the ball type harmonic reducer includes a flexspline, an output flange, balls, elastic members, a flexspline pressing plate, and a spring flange. A groove is formed on the end face of the output flange, and a groove is formed on the opposite spring flange face. The balls are clamped between the groove of the output flange and the groove of the spring flange. A cylindrical shaft is provided at the center of the output flange, the spring flange is sleeved on the cylindrical shaft, and then a set of elastic members are sleeved on the cylindrical shaft and pressed on the spring flange. One end of the cylindrical shaft is integrally fastened with the flexspline pressing plate, and the tail of the flexspline is inserted into the output flange. The flexspline pressing plate limits the flexspline on the output flange. During normal operation, the elastic members press the balls tightly to integrate the flexspline and the output flange. The flexspline transmits the torque to the output flange through the balls. When the load torque is greater than the limiting torque, the axial force generated by the balls in the groove pushes the elastic members to compress, causing the balls to disengage from the groove of the output flange. Subsequently, rotational slip occurs between the flexspline and the output flange, interrupting the torque transmission.

[0011] More specifically, the elastic member is a disc spring or a compression spring.

[0012] Compared with the prior art, the advantages of the present invention are as follows: Since the torque limiting device is integrated inside the harmonic reducer, the end face space of the cup-shaped flexspline and the end face space of the output flange are fully utilized. Therefore, the structure is compact and the volume is small. Different elastic members can also be replaced or the compression amount can be changed to adjust the torque limiting range. Description of the Drawings

[0013] Figure 1 It is a schematic structural diagram of the torque limiting device of the ball type harmonic reducer according to Embodiment 1 of the present invention.

[0014] Figure 2 It is a schematic structural diagram of the torque limiting device of the ball type harmonic reducer according to Embodiment 2 of the present invention. Detailed Embodiments

[0015] The present invention will be further described in detail below with reference to the drawings and embodiments. Embodiment 1

[0016] As Figure 1 shown, the torque limiting device of the ball type harmonic reducer includes a flexspline 1, an output flange 4, balls 6, elastic members 5, a flexspline pressing plate 2, and a spring flange 3.

[0017] A flexspline groove 11 is provided on the end face of the flexspline 1, and a groove 31 is formed on the circumferential surface of the opposite spring flange 3. The balls 6 are clamped in the flexspline groove 11 and the spring flange groove 31 between the end face of the flexspline and the spring flange 3.

[0018] A cylindrical shaft 41 is provided at the center of the output flange 4, and an internal space 42 is provided outside the cylindrical shaft 41. A set of elastic members 5 are placed in the internal space 42 of the output flange 4.

[0019] A groove 12 is formed on the end face of the flexspline 1 and sleeved on the cylindrical shaft 41 on the output flange 4. The flexspline pressing plate 2 is fastened to the cylindrical shaft 41 on the output flange 4 with bolts 7 to axially limit the flexspline 1.

[0020] During normal operation, the elastic member 5 in the speed reducer presses the ball 6, so that the flexspline 1 and the output flange 4 are integrated into one body, and the flexspline 1 transmits torque to the output flange 4 through the ball 6.

[0021] When the load torque is greater than the limit torque, the axial force generated by the ball 6 in the groove pushes the elastic member 5 to compress, so that the ball 6 disengages from the flexspline groove 11, and then rotational slip occurs between the flexspline 1 and the output flange 4, interrupting the torque transmission, thereby protecting the harmonic speed reducer from impact damage.

[0022] The torque limit device of this ball-type harmonic speed reducer can adjust the torque limit range by replacing different elastic members or changing the compression amount. Embodiment 2

[0023] As Figure 2 shown, the torque limit device of the ball-type harmonic speed reducer includes a flexspline 1, an output flange 4, a ball 6, an elastic member 5, a flexspline pressing plate 2, and a spring flange 3.

[0024] An output flange groove 43 is formed on the end face of the output flange 4, and a spring flange groove 31 is formed on the circumferential surface of the opposite spring flange 3. The ball 6 is clamped between the output flange groove 43 of the output flange 4 and the spring flange groove 31 of the spring flange 3.

[0025] A cylindrical shaft 41 is provided at the center of the output flange 4. The spring flange 3 is sleeved on the cylindrical shaft 41, and then a set of elastic members 5 are sleeved on the cylindrical shaft 41 and pressed on the spring flange 3. One end of the cylindrical shaft 41 is fastened to the flexspline pressing plate 2 as a whole. The tail 13 of the flexspline 1 is inserted into the output flange 4, and the flexspline pressing plate 2 limits the flexspline 1 on the output flange 4; this torque limit device is integrated in the internal space of the flexspline 1, which can reduce the axial length.

[0026] During normal operation, the elastic member 5 in the speed reducer presses the ball 6, so that the flexspline 1 and the output flange 4 are integrated into one body, and the flexspline 1 transmits torque to the output flange 4 through the ball 6.

[0027] When the load torque is greater than the limit torque, the axial force generated by the ball 6 in the groove pushes the elastic member 5 to compress, so that the ball disengages from the output flange groove 41, and then rotational slip occurs between the flexspline 1 and the output flange 4, interrupting the torque transmission, and protecting the harmonic speed reducer from impact damage.

[0028] The torque limit range of this ball-type harmonic reducer torque limiting device can be adjusted by replacing different elastic components or changing the compression amount.

Claims

1. A ball-type harmonic reducer torque limiting device, characterized in that: It includes a flexible wheel, an output flange, a ball, an elastic member, a flexible wheel pressure plate, and a spring flange; the end face of the flexible wheel is provided with a flexible wheel groove, and the opposite spring flange face is provided with a spring flange groove, and the ball is clamped in the flexible wheel groove and the spring flange groove; during normal operation, the elastic member presses the ball, so that the flexible wheel and the output flange are integrated, and the flexible wheel transmits the torque to the output flange through the ball; when the load torque is greater than the limit torque, the axial force generated by the ball pushes the elastic member to compress, so that the ball is disengaged from the flexible wheel groove, and then rotation slip occurs between the flexible wheel and the output flange, so that the torque transmission is interrupted.

2. The ball-type harmonic reducer torque limiting device according to claim 1, characterized in that: A cylindrical shaft is arranged at the center of the output flange, a group of elastic parts are placed in the cylindrical shaft, a groove is opened on the end face of the flexible wheel, and the elastic parts press the ball through the flexible wheel pressure plate.

3. The torque limiting device of the ball-type harmonic reducer includes a flexible wheel, an output flange, a ball, an elastic member, a flexible wheel pressure plate, and a spring flange; an output flange groove is provided on the end face of the output flange, and a spring flange groove is provided on the opposite spring flange surface, and the ball is clamped between the output flange groove and the spring flange groove; a cylindrical shaft is arranged at the center of the output flange, the spring flange is inserted into the cylindrical shaft, and then a group of elastic members are inserted into the cylindrical shaft and pressed on the spring flange, one end of the cylindrical shaft is fastened to the flexible wheel pressure plate as a whole, the tail of the flexible wheel is inserted into the output flange, and the flexible wheel pressure plate limits the flexible wheel on the output flange; during normal operation, the elastic member presses the ball, so that the flexible wheel and the output flange are integrated, and the flexible wheel transmits the torque to the output flange through the ball; when the load torque is greater than the limiting torque, the axial force generated by the ball in the groove pushes the elastic member to compress, so that the ball is disengaged from the output flange groove, and then rotation slip occurs between the flexible wheel and the output flange, so that the torque transmission is interrupted.

4. The ball-type harmonic reducer torque limiting device according to claim 1, 2 or 3, characterized in that: The elastic member is a disc spring or a compression spring.

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