TW201317486A - Low backlash gear mechanism and device - Google Patents

Abstract

The present invention provides a low backlash gear mechanism and a device, which are capable of repeatedly rotating a motor in both forward and reverse directions, easy to be assembled, and easy to adjust torque. Under a situation of a deepest part of a hemisphere hole 17 and a deepest part of a slot 18a being offset along a circumferential direction, and under a situation of a ball 24 contacting an inclined surface of the deepest part of the slot 18a, the low backlash gear mechanism 10 is assembled. Therefore, if a driven plate 18 is pressed by a disc spring 16 along an axial direction, a main sear 15 and a sub gear 25 are applied by torque, so as to reduce the backlash. The present invention has a simple structure, and is easy for assembly. An installation angle can be adjusted according to screw status of a screw nut 14, so as to simply adjust the torque applied to the main gear 15 and the sub gear 25.

Description

Low backlash gear mechanism and device

The present invention relates to a low backlash gear mechanism and apparatus for automatically reducing backlash between a gear and a tooth surface of a gear when the gear is stopped.

The smooth operation of a pair of gears requires a backlash between the tooth faces, but in devices requiring high precision, devices requiring less backlash are required. For example, in a speed reducer used in a transport apparatus that requires repeated positioning accuracy, this tendency is remarkable. When the backlash is large, when the output shaft is stopped, the output shaft is generated due to the reaction force of the inertial force of the conveyed object or the like. In the case of the torque opposite to the direction of rotation so far, since the stop position is slightly deviated, there is a problem that the workpiece cannot be accurately and reliably stopped at the fixed position. Therefore, it is required to automatically eliminate the backlash when stopping. Further, when the forward rotation and the reverse rotation of the motor are repeated, a low backlash gear mechanism and a device that can correspond to the forward rotation and the reverse rotation of the motor are required.

Up to this point, the low backlash gear mechanism and the device have been developed in many cases, and as an example, there are the following.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2001-74126

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2007-198600

[Patent Document 3] Japanese Patent Laid-Open No. Hei 8-74972

Patent Document 1 discloses that there is two gears on the coaxial line, One of the gears is provided with a low backlash gear mechanism of a helical torsion coil spring that is pressed in the direction of rotation with respect to the other gear by the adjusting member and the fixing screw. According to this configuration, the strength of the reaction force of the helical torsion spring can be easily adjusted by fixing the fixing screw with a fixing screw in a state in which the rotation adjusting member applies a torsion moment.

Patent Document 2 discloses a low backlash gear mechanism in which two gears are provided coaxially, and one of the gears is provided with a long hole, and the steel ball, the elastic body, and the adjusting means are provided so as to be housed in the hole. The pressing mechanism inserts the guiding portion of the gear disposed on the other side into the pressing mechanism, and the groove provided in the guiding portion is in contact with the steel ball of the pressing mechanism, and the self-guide portion passes through the steel when the gear rotates The ball applies a moment in the rotational direction to the elastic body to compress the elastic body, and when the gear is stopped, the reaction force of the elastic body is applied to the guiding portion to rotate the gear provided with the guiding portion, thereby reducing the backlash. Further, the pressure applied to the elastic body can be adjusted in advance by the adjustment means provided in the pressing mechanism.

Patent Document 3 discloses a low backlash gear device in which a drive gear and two neutral gears meshed with drive gears provided on different shafts, a driven gear disposed coaxially with the respective neutral gears, and The output gear combination of the passive gear meshing imparts a desired torque to one of the shafts provided with the neutral gear and the driven gear of the gears by a torque wrench or the like, and is solidified by the wedge-shaped clamping member in this state. The gear that is engaged with the output gear produces a phase difference. According to the device, a phase difference is generated between the two driven gears by a torque applied to one of the axes, and the pressing force is made. Used to separate the directions of each other, thereby reducing the backlash.

In the case of the low backlash gear mechanism of Patent Document 1, the characteristics of the helical torsion spring are preferably such that the gear rotates in the direction in which the coil is wound, and therefore it is not suitable for repeating the forward rotation and the reverse rotation. Moreover, since the structure is fixed by the fixing screw after adjusting the torque of the spiral torsion spring by the adjusting member, assembly is difficult.

In the low backlash gear mechanism of Patent Document 2, when the pressure applied to the elastic body is adjusted by the adjusting means, the pressing mechanism must be detached from the gear for each adjustment, and then assembled again after adjustment, so Convenience. Moreover, the smaller the size of the gear, the more the pressing mechanism that operates much smaller than the gear, so that the operation becomes more difficult.

In the low backlash gear device of Patent Document 3, it is necessary to fix the shaft by a torque wrench or the like, and it is necessary to fix the shaft by a wedge-shaped holding member. Therefore, assembly is difficult. Moreover, according to this configuration, there is a problem that adjustment of the torsional moment is difficult.

Therefore, the present invention has been made in view of the above problems of the prior art, and an object of the present invention is to provide a low backlash gear mechanism and apparatus which can be easily and easily assembled, and can be easily adjusted even when the motor is reversed. .

The present invention solves the above problems by a low backlash gear mechanism, The low backlash gear mechanism is characterized by comprising: a main gear coupled to the shaft; a sub gear rotatably disposed on the shaft and provided with at least one hemispherical hole; a ball fitted to the hemisphere a type of hole; a driven plate provided with a V-shaped groove of a circumferential cross section of the size of the ball fitable, coupled to the shaft and movable in the axial direction; a nut screwed into the shaft; And an elastic body disposed between the nut and the driven plate; and the nut, the elastic body, the driven plate, the ball, the auxiliary gear, and the main gear are sequentially disposed from one end of the shaft; and the auxiliary gear The driven plate is pressed by the elastic body in a state where the deepest portion of the hemispherical hole into which the ball is fitted and the deepest portion of the groove are displaced in the rotational direction, and the ball is in contact with the inclined surface of one of the grooves.

Further, as in the second aspect, it is preferable to include a driven flange which is screwed to the sub-gear, and has at least one hemispherical hole into which the ball is fitted and a self-insertion for inserting the screw The front side is an elliptical long hole.

Moreover, as in the third aspect, it is preferable to include an input gear or an output gear provided on the input shaft or the output shaft, and an output gear having two gears that are disposed on the output shaft or the input shaft and are disposed on the output shaft or the input shaft. Or input gear; set one of the above-mentioned output gears or input gears as the main gear, the other gear as the sub-gear, and assemble the low-gear gear as in the technical solution 1 or 2 in the output gear or the input gear. mechanism.

Further, as in the fourth aspect, it is preferable to provide a low backlash gear device including an input gear provided on the input shaft, an output gear provided on the output shaft, a first intermediate gear, and a second intermediate gear. The first intermediate gear and the second intermediate gear are provided on the input gear and the output An intermediate output gear that meshes with the input gear and an intermediate input gear that meshes with the output gear; and an intermediate input gear of the first intermediate gear or the second intermediate gear is a main gear or a sub-gear, and an intermediate output is provided The gear is set as a sub-gear or a main gear, and the low backlash gear mechanism according to claim 1 or 2 is incorporated in the first intermediate gear or the second intermediate gear.

According to the invention, the deepest portion of the hemispherical hole in which the ball of the sub-gear is fitted and the deepest portion of the V-shaped groove in the circumferential direction are offset in the rotation direction, and the ball is in contact with the slope of one of the grooves. In the state where the driven plate is pressed by the elastic body, the driven plate is pressed by the reaction force of the elastic body, whereby the ball moves in the direction to be fitted in the groove, thereby eliminating the deepest portion and the groove of the hemispherical hole. The offset of the position of the deepest part. Therefore, the torque in the relative rotational direction, that is, the torsional moment is generated in the driven plate and the auxiliary gear. Since the driven plate is coupled to the shaft, the torque applied to the driven plate passes through the shaft and passes through the main gear coupled to the shaft. As a result, a torque is applied to the main gear and the sub-gear, and the main gear and the sub-gear are opposite to each other. Direction rotation. In this way, when the main gear and the sub gear are meshed with the other gears, the tooth surfaces on both sides of the other gears are in contact with either the main gear or the sub gears, so that the backlash can be reduced.

Further, a nut, an elastic body, a driven plate, a ball, a sub-gear, and a main gear are disposed in sequence from one end of the output shaft, and the deepest portion of the hemispherical hole and the V-shaped section of the sub-gear are fitted to the ball of the sub-gear. In the state where the deepest portion of the groove is displaced in the rotation direction and the ball is in contact with the inclined surface of one of the grooves, the driven plate is pressed by the elastic body to be attached to the simple structure, so that it can be easily assembled.

Moreover, the bullet can be adjusted by the screwing angle of the nut screwed to the output shaft The reaction force of the sexual body, that is, the force pushing the driven plate, can easily adjust the magnitude of the torsional moment.

Further, as in the second aspect, the configuration includes a hemispherical hole having a ball fitted to the sub-gear and a driven flange having an elliptical long hole from the front for inserting the screw. By changing the mounting position of the screw in the range of the long hole, the mounting angle of the sub-gear of the driven flange can be adjusted. Therefore, as a result, the position of the hemispherical hole in the circumferential direction can be adjusted, so that the adjustment can be easily performed. The offset between the deepest part of the hemispherical hole and the deepest part of the V-shaped groove of the section.

Further, as in the third aspect of the invention, preferably, the output gear is included in a low backlash gear device including an input gear provided on the input shaft and an output gear having two gears disposed on the output shaft of the input gear. One of the gears is set as the main gear, and the other gear is set as the auxiliary gear, and the low backlash gear mechanism according to the first or second aspect of the invention is incorporated in the output gear. In this case, the torque of the input gear is rotated. In either case of right rotation or left rotation, it acts in the opposite direction to the torsional moment imparted to the main gear or the sub gear. Specifically, when torque is applied to the main gear from the input gear, the main gear is coupled to the output shaft, so the torque from the input gear is immediately transmitted to the output shaft. At this time, the input gear and the output gear rotate in a state in which the assembly is maintained, that is, in a state where the backlash is maintained to be small, and when the rotation is stopped, the backlash is maintained to be small. On the other hand, when a torque is applied to the sub-gear from the input gear, the sub-gear is rotatably disposed on the output shaft, so that the torque from the input gear is not immediately transmitted to the output shaft. Thus, the torque from the input shaft exceeds the torque imparted to the counter gear. In the hour, the force in the opposite direction to the torsional moment acts on the sub-gear, applying the force in the direction in which the ball is intended to escape from the groove, in other words, the deepest portion of the hemispherical hole and the deepest portion of the V-shaped groove of the section are further offset. . Therefore, a force in the axial direction corresponding to the amount by which the ball is moved out of the groove of the V-shaped cross section is applied to the driven plate. Further, since the driven plate is movable in the axial direction, the driven plate moves in the axial direction, and the elastic body contacting the driven plate is compressed by the amount corresponding to the movement. When the input gear is stopped, the driven plate is pushed back in the axial direction by the reaction force of the elastic body, so that the ball is to be embedded in the direction of the V-shaped groove of the cross section, that is, the deepest portion and the cross section of the hemispherical hole are eliminated. The direction of the offset of the position of the deepest portion of the V-shaped groove causes the main gear and the sub-gear to generate a torsional moment, and thus automatically returns to the state at the time of assembly, that is, the state in which the backlash is small. Here, when the main gear coupled to the output shaft rotates in a direction in which the backlash is small, the output shaft rotates. Therefore, there is a case where the output shaft is slightly rotated during the process of reducing the backlash after the motor is stopped. Further, when the sub-gear does not rotate in the direction in which the backlash is reduced, the sub-gear is rotatably provided on the output shaft, so that the output shaft does not rotate. Furthermore, when the input shaft is directly connected to the motor, when the motor is stopped, the input shaft is fixed without rotation by the servo lock. Therefore, even when the motor is stopped, the main gear or the auxiliary gear is reduced by the torque. The backlash rotates and the input shaft does not rotate through the input gear.

Further, in another aspect of the invention, the output gear provided in the output shaft and the low backlash of the input gear having the two-piece gear provided on the input shaft engaged with the output gear may be provided. In the gear unit, the gear of one of the input gears is set as the main gear, and the other is The gear is set as a sub-gear, and a low backlash gear mechanism as in the first or second aspect of the invention is incorporated in the input gear. The basic actuation principle of this case is the same as the case where the output gear set on the output shaft is incorporated into the low backlash gear mechanism. Furthermore, when the input shaft is directly connected to the motor, when the motor is stopped, the input shaft is fixed without being rotated by the servo lock of the motor, so that the input shaft is connected in the process of reducing the backlash. The main gear cannot be rotated in the direction of reducing the backlash. At this time, the sub-gear rotates by the torsional moment until the tooth surface of the output gear contacts the main gear to rotate the output gear to reduce the backlash. Therefore, there is a case where the output shaft is slightly rotated.

Further, as in the fourth aspect, the input gear provided in the input shaft, the output gear provided in the output shaft, the first intermediate gear, and the second intermediate gear are provided, and the first intermediate gear and the second intermediate gear are provided to the input gear. And an intermediate output gear that meshes with the input gear and an intermediate input gear that meshes with the output gear; and an intermediate input gear of the first intermediate gear or the second intermediate gear is a main gear or a sub gear, and The intermediate output gear is a sub-gear or a main gear, and the low-backlash gear mechanism according to the first or second intermediate gear is incorporated in the first intermediate gear or the second intermediate gear. According to the above configuration, the present invention can also be applied to the two-stage gear. Low backlash gear mechanism.

Further, depending on which of the main gear or the sub-gear is rotated when the backlash is reduced, there is a case where the output shaft is slightly rotated after the motor is stopped, which is the same as the case of the third aspect.

Hereinafter, embodiments of the present invention will be described with reference to Figs. 1 to 9 . However, the present invention is not limited to this embodiment. Furthermore, the backlash is exaggerated in the drawings for the sake of convenience.

The low backlash gear mechanism 10 of FIG. 1 includes: a main gear 15 coupled to the shaft 12; a sub-gear 25 rotatably disposed on the shaft 12 and provided with a hemispherical hole 17; a ball 24 The hole plate 17 is fitted to the hemispherical shape; the driven plate 18 is provided with a groove-shaped groove 18a having a V-shaped cross section in the circumferential direction in which the ball 24 can be fitted, and is coupled to the shaft 12 to be movable in the axial direction; the nut 14 is Screwed into the shaft 12; and a disc spring 16, which is an elastic body disposed between the nut 14 and the driven plate 18. Further, as long as the hemispherical hole 17 can hold the ball 24, it may have a shape other than a hemispherical shape such as a groove shape. Further, the groove 18a may be a roller instead of the ball 24 as long as it has a V-shaped cross section in the circumferential direction.

As shown in FIG. 2, the shaft 12 and the driven plate 18 are connected by key fastening by the key portion 18b. Therefore, the main gear 15 coupled to the shaft 12 rotates in the same direction as the driven plate 18. Further, the position of the deepest portion of the hemispherical hole 17 and the deepest portion of the groove 18a is shifted in the circumferential direction, so that the ball 24 is assembled in contact with the inclined surface of one of the grooves 18a. At this time, when the driven plate 18 is pressed in the axial direction by the disk spring 16, the ball 24 is moved in the direction to be inserted into the groove 18a, so that the driven plate 18 is to be rotated in the left rotational direction, and the sub-gear 25 is intended to Rotate in the right rotation direction. As a result, the torque in the left rotation direction of the driven plate 18 is transmitted to the main gear 15 via the shaft 12, so that the main gear 15 and the sub-gear 25 can be given torque in the opposite direction, and the torque can be imparted. In the deepest portion of the hemispherical hole 17 that generates the torsional moment and the deepest portion of the groove 18a In the relationship, as shown in FIG. 1, by engaging the main gear 15 and the sub-gear 25 with the other gears 55, one of the main gear 15 and the sub-gear 25 is pressed against the tooth surfaces 56 and 57 of the other gear 55, thereby Can reduce backlash. Further, the main gear 15 or the sub-gear 25 is in contact with the tooth faces 56 or 57 of the other gears 55, whereby the positions of the main gear 15, that is, the driven plate 18 and the sub-gear 25 are fixed, so that the ball 24 cannot be more desired. The fitting is moved in the direction of the groove 18a, and thus is stabilized in the state shown in Fig. 2. Further, in Fig. 2, the position of the deepest portion of the hemispherical hole 17 is less than the position of the deepest portion of the groove 18a, and the ball 24 is in contact with the slope of both sides of the groove 18a, even by the disk shape. When the spring 16 pushes the driven plate 18 and does not generate a torsional moment, it is necessary to set it as shown in Fig. 2 when assembling (stopping). Further, in Fig. 2, the deepest portion of the hemispherical hole 17 is located on the left side, and the deepest portion of the groove 18a is located on the right side. However, when it is reversed, the torque in the opposite direction is of course given. Further, the tightening angle of the nut 14 is changed in accordance with the screwing state of the nut 14 to the shaft 12, whereby the force by which the disc spring 16 presses the driven plate 18 can be adjusted, so that the magnitude of the torsional moment can be easily adjusted. Thus, the torsional moment corresponding to the use or environment of the low backlash gear mechanism 10 can be easily achieved. Furthermore, it is of course understood by the laws of mechanics that the closer the position of the hemispherical hole 17 and the groove 18a is to the axis 12, the smaller the torque and the greater the torque.

Next, Fig. 3 is a front view when the low backlash gear unit 100 of the low backlash gear mechanism 10a is stopped (assembled). The low backlash gear device 100 is meshed with an input gear 55a of an input shaft 52a coupled to a motor (not shown) and a main gear 15a and a sub gear 25a of a low backlash gear mechanism 10a provided on the output shaft 12a. Furthermore, it is also possible to make the input shaft 52a and the output The shaft 12a has the opposite configuration, that is, the low backlash gear mechanism 10a is provided on the input shaft 52a. However, since the configuration is substantially the same, the description thereof will be omitted.

The sub-gear 25a includes a driven flange 28 including a hemispherical hole 28a into which the ball 24 is fitted, and an elongated hole 28b for inserting the screw 26 from the front. By inserting the driven flange 28, the mounting position of the screw 26 to the sub-gear 25a is changed within the range of the long hole 28b, and by adjusting the attachment angle of the follower flange 28 to the sub-gear 25a, the hemispherical type can be obtained. The position of the hole 28a is offset. On the other hand, as shown in Fig. 4, the driven plate 18 is fastened to the output shaft 12a by the key portion 18b after the driven flange 28 is attached to the sub-gear 25a by the screw 26. Therefore, it is fixed at the position of the groove 18a of the follower plate 18. Therefore, the mounting position of the driven flange 28 is adjusted to adjust the position of the hemispherical hole 28a, whereby the position of the deepest portion of the hemispherical hole 28a and the deepest portion of the V-shaped groove 18a can be easily adjusted. Offset condition. Further, the low backlash gear mechanism 10a presses the plurality of coil springs 16a by the nut 14a to press the driven plate 18. As described above, a spring such as a disc spring or a coil spring can be applied as the elastic body, and an elastic body such as rubber may be applied.

4 and 5 are enlarged cross-sectional views showing important parts of the low backlash gear mechanism 10a when the low backlash gear device 100 is stopped (assembled) and rotated. Furthermore, for convenience of explanation, no hatching is applied. When the low backlash gear device 100 is stopped (assembled), as shown in FIG. 4, the nut 14a is screwed into the output shaft 12a, and the coil spring 16a is pressed, so that the driven plate 18 is pressed by the coil spring 16a. Therefore, the ball 24 fitted to the hemispherical hole 28a is intended to move in the direction to be fitted into the groove 18a, so that the self-driven plate 18 is fastened by the key 18b. The output shaft 12a generates a torque in the left rotation direction indicated by an arrow A in the main gear 15a, and generates a torque in the right rotation direction indicated by an arrow B in the sub-gear 25a. Further, as shown in Fig. 3, the main gear 15a is in contact with the tooth surface 56a of the input gear 55a, and the sub gear 25a is in contact with the tooth surface 57a of the input gear 55a, whereby the ball 24 of Fig. 4 cannot be more embedded in the groove. When the low backlash gear device 100 is stopped (assembled), as shown in FIG. 4, the position of the deepest portion of the hemispherical hole 28a and the deepest portion of the groove 18a are shifted in the circumferential direction. In other words, since the main gear 15a is pressed against the tooth surface 56a of the input gear 55a and the sub-gear 25a is pressed against the tooth surface 57a of the input gear 55a by the torsional moment, the backlash is reduced. Further, when the depth of the deepest portion of the hemispherical hole 28a is less than the position of the deepest portion of the groove 18a, and the ball 24 is in contact with the slope of both sides of the groove 18a, even if the coil spring 16a is pressed, the driven is driven. The plate 18 also does not generate a torsional moment, so that the low backlash function cannot be obtained as long as it is not in the state shown in Fig. 4 when it is stopped (assembled).

Even if the input gear 55a of the low backlash gear device 100 shown in Fig. 3 is rotated in either of the right and left directions, the torque in the opposite direction to the torsional moment applied to the main gear 15a or the sub gear 25a also functions. Specifically, when the input gear 55a is rotated to the left and torque is applied to the main gear 15a, since the main gear 15a is coupled to the output shaft 12a, the torque from the input gear 55a is immediately transmitted to the output shaft 12a. At this time, the input gear 55a and the output gear 10a maintain the state at the time of assembly as shown in FIG. 4, that is, the state in which the backlash is maintained to be small, and the state in which the backlash is maintained is maintained even if the rotation is stopped. On the other hand, when the input gear 55a rotates to the right and torque is applied to the sub-gear 25a, the sub-gear 25a is rotatably provided on the output shaft 12a, and thus The torque of the input gear 55a is not immediately transmitted to the output shaft 12a, and when the torque from the input shaft 52a exceeds the torque applied to the sub-gear 25a, the sub-gear 25a starts to rotate in the opposite direction to the torsional moment. At this time, as shown in FIG. 5, the important portion of the low backlash gear mechanism 10a when the low backlash gear device 100 rotates is moved in the direction in which the ball 24 opposite to the direction in which the torque is generated is released from the groove 18a, and the driven plate 18 is moved. The pressing movement in the axial direction corresponds to the moving distance thereof, thereby compressing the coil spring 16a. At this time, until the force with which the ball 24 is to be released from the groove 18a is equalized by the reaction force of the coil spring 16a due to the torque transmitted from the input gear 55a, or until the offset of the position of the main gear 15a and the sub-gear 25a disappears, The tooth surface 57a of the input gear 55a is in contact with the main gear 15a and the sub-gear 25a, and the position of the deepest portion of the hemispherical hole 28a and the deepest portion of the groove 18a cannot be further shifted, and the ball 24 is detached from the groove 18a. Move in direction. Next, when the rotation of the input gear 55a is stopped, the state of FIG. 4, that is, the state in which the backlash is small, is automatically restored by the reaction force of the compressed coil spring 16a. Further, if the ball 24 is completely detached from the groove 18a during the rotation, the torsional moment cannot be generated even if the reaction force of the elastic body is imparted. Therefore, it is necessary to set the reaction of the elastic body to the extent that the ball 24 does not completely escape from the groove 18a during the rotation. The strength of the force or the displacement of the deepest portion of the hemispherical hole 28a and the position of the deepest portion of the groove 18a.

Next, the operation of the low backlash gear unit 100 will be described in detail. For example, when the input shaft 52a of the low backlash gear device 100 of FIG. 3 is rotated to the left, torque is transmitted from the tooth surface 56a of the input gear 55a to the main gear 15a, and the main gear 15a and the output shaft coupled to the main gear 15a are output. 12a starts to rotate right. That is, the torque from the input shaft 52a is immediately transmitted to the output shaft 12a. also, At this time, the driven plate 18 fastened to the output shaft 12a, the nut 14a screwed into the output shaft 12a, and the coil spring 16a provided between the nut 14a and the driven plate 18 start the right rotation in the same manner. On the other hand, the torque from the input gear 55a is not transmitted to the sub-gear 25a. At this time, since the torque of the right direction of rotation is given to the main gear 15a from the input gear 55a, and the torsion moment of the right direction of rotation is given to the sub-gear 25a, the disc spring 16a is not compressed, and the main gear 15a and the sub-gear 25a are Rotate right in a slave mode. Therefore, the state shown in Fig. 5 is not maintained during the rotation, and the state shown in Fig. 4 is maintained, that is, the torque is transmitted from the input shaft 52a to the output shaft 12a while maintaining the backlash. Therefore, even when the rotation of the input shaft 52a is stopped, the state in which the backlash is small as shown in Fig. 4 is maintained, so that the output shaft 12a does not rotate after the stop.

On the other hand, when the input shaft 52a of FIG. 3 is rotated rightward, torque is transmitted from the tooth surface 57a of the input gear 55a to the sub-gear 25a. The sub-gear 25a is rotatably provided on the output shaft 12a, so that the torque is not immediately transmitted to the output shaft 12a, and when the torque from the input shaft 52a exceeds the magnitude of the torsional moment imparted to the sub-gear 25a, the sub-gear 25a Start the left rotation in the opposite direction of the torque. At this time, the torque is also transmitted to the driven flange 28 provided in the sub-gear 25a and the ball 24 provided in the hemispherical hole 28a of the driven flange 28, and starts to rotate in the same direction as the sub-gear 25a. Therefore, until the torque applied to the ball 24 is equalized with the reaction force of the coil spring 16a, or until the tooth surface 57a of the input gear 55a is connected to the main gear 15a, the ball 24 moves in the direction in which the groove 18a is to be removed, and becomes a figure. The positional relationship between the ball 24 and the groove 18a shown in Fig. 5, and the torque is transmitted from the ball 24 to the driven plate 18, as a result, the torque is transmitted to the output shaft 12a. When the input shaft 52a is stopped from this state, the coil spring 16a is used. The reaction force and the ball 24 are moved in the direction to be fitted in the groove 18a, thereby generating a torsional moment. Therefore, the sub-gear 25a rotates to the right and the main gear 15a rotates to the left. Therefore, the output shaft 12a rotates slightly leftward with the left rotation of the main gear 15a, and the input gear 55a that is in contact with the sub-gear 25a rotates slightly leftward. Further, as shown in FIG. 3, when the main gear 15a is in contact with the tooth surface 56a of the input gear 55a, and the sub gear 25a is in contact with the tooth surface 57a of the input gear 55a, the stop is stopped. Here, the input shaft 52a is directly coupled to a motor (not shown), and when the motor is fixed without being rotated by a servo lock, the input shaft 52a is rotated without being rotated by the servo lock of the motor. Since it is fixed, the input gear 55a and the sub-gear 25a which is in contact therewith are not rotated by the torsional moment, and only the main gear 15a is rotated leftward to make the backlash small. Since the main gear 15a is coupled to the output shaft 12a, the output shaft 12a coupled to the main gear 15a also slightly rotates in accordance with the amount by which the main gear 15a rotates.

Next, with respect to the operation in the case where the low backlash gear mechanism 10a is provided on the input shaft, and the above-described case where the low backlash gear mechanism 10a is provided on the output shaft, the input of Fig. 3 is hereinafter referred to in this paragraph. The shaft 52a will be described as an output shaft 52a, the input gear 55a as an output gear 55a, and the output shaft 12a as an input shaft 12a.

When the input shaft 12a is rotated to the left, the torque autonomous gear 15a is transmitted to the tooth surface 56a of the output gear 55a, and the output gear 55a and the output shaft 52a start to rotate rightward. That is, the torque from the input shaft 12a is immediately transmitted to the output shaft 52a. At this time, the torque from the input shaft 12a and the torque applied to the main gear 15a are in the same direction, and therefore do not become in the state shown in FIG. 5, but maintain the state as shown in FIG. 4, that is, maintain the backlash. Torque from a small state The input shaft 12a is transmitted to the output shaft 52a. Therefore, even when the rotation of the input shaft 12a is stopped, the state in which the backlash is small as shown in Fig. 4 is maintained, so that the output shaft 52a does not rotate after the stop.

On the other hand, when the input shaft 12a is rotated to the right, there is a slight gap between the main gear 15a and the tooth surface 57a of the output gear 55a. Therefore, if the main gear 15a starts to rotate right, the driven plate 18 and the groove 18a are also Similarly, the right rotation is performed until the torque applied to the groove 18a is equalized with the reaction force of the coil spring 16a, or until the main gear 15a contacts the tooth surface 57a of the output gear 55a, the ball 24 is moved in the direction in which the groove 18a is to be withdrawn. The positional relationship between the ball 24 and the groove 18a shown in Fig. 5 is obtained, and torque is transmitted from the groove 18a to the driven flange 28 via the ball 24 and the hemispherical hole 28a. As a result, the torque autonomous gear 15a or the pair The gear 25a is transmitted to the output gear 55a and the output shaft 52a.

Next, when the input shaft 12a is stopped, the ball 24 is moved in the direction to be fitted in the groove 18a by the reaction force of the coil spring 16a, thereby generating a torsional moment. Therefore, since the main gear 15a is rotated to the left and the sub-gear 25a is rotated to the right, the input shaft 12a is slightly rotated to the left with the left rotation of the main gear 15a, and the output gear 55a that is in contact with the sub-gear 25a is slightly rotated to the left. Further, as shown in Fig. 3, when the main gear 15a comes into contact with the tooth surface 56a of the output gear 55a, the sub-gear 25a comes into contact with the tooth surface 57a of the output gear 55a, and then stops. Here, the input shaft 12a is directly coupled to a motor (not shown), and when the motor is fixed by rotation without being rotated by the servo lock, the main gear 15a coupled to the input shaft 12a cannot be rotated in the direction of reducing the backlash. Therefore, the state in which the sub gear 25a is in contact with the tooth surface 57a of the output gear 55a by the torsional moment The lower right rotation rotates until the tooth surface 56a of the output gear 55a comes into contact with the main gear 15a to rotate the output gear 55a, so that the output shaft 52a slightly rotates.

Next, Fig. 6 is a front view of the low backlash gear device 200 of the two stages of the low backlash gear mechanism 10b when it is stopped (assembled). The low backlash gear device 200 includes an input gear 55b provided on an input shaft 52b coupled to a motor (not shown), an output gear 65 provided on the output shaft 62, and a first intermediate portion provided between the input gear 55b and the output gear 65. The gear 30 and the low backlash gear mechanism 10b as the second intermediate gear. The first intermediate gear 30 includes a first intermediate output gear 35 and a first intermediate input gear 45, and the low backlash gear mechanism 10b includes a secondary gear 25b as a second intermediate output gear on the shaft 12b as a second intermediate input gear. Main gear 15b. Further, the first intermediate output gear 35 and the sub gear 25b, and the first intermediate input gear 45 and the main gear 15b have the same number of teeth, and it is preferable that the sub gear 25b and the main gear 15b have a smaller tooth width than the first intermediate output gear 35, The first intermediate input gear 45. Further, the ball 24 is fitted into the hemispherical hole 28a, and the deepest portion of the hemispherical hole 28a is displaced from the deepest portion of the V-shaped groove 18a in the circumferential direction, and the ball 24 is in contact with one of the grooves 18a. In this state, the driven plate 18 is pressed by the disc spring 16b as an elastic body. Like the low backlash gear mechanism 10b, the hemispherical hole 28a provided in the driven flange 28, the ball 24 fitted thereto, and the groove-shaped groove 18a having a V-shaped cross section in the circumferential direction may be formed, and a plurality of grooves may be provided. Screw 26 and long hole 28b. Similarly to the low backlash gear mechanisms 10 and 10a, the low backlash gear mechanism 10b generates a torque as a torque in the opposite direction to the counter gear 25b and the main gear 15b. Therefore, when the low backlash gear device 200 is stopped (assembled), as shown in FIG. 6, the input The tooth surface 56b of the gear 55b is in contact with the first intermediate output gear 35, the tooth surface 57b of the input gear 55b is in contact with the sub gear 25b, and the tooth surface 66 of the output gear 65 is in contact with the main gear 15b, and the tooth surface of the output gear 65 is output. 67 is in contact with the first intermediate input gear 45, whereby the tooth faces 56b, 57b on both sides of the gear 55b and the tooth faces 66, 67 on both sides of the output gear 65 and the first intermediate output gear of the first intermediate gear 30 are input. 35. The first intermediate input gear 45, the main gear 15b of the low backlash gear mechanism 10b, or either of the sub gears 25b are in contact with each other, so that the backlash is small.

Here, the operation of the low backlash gear device 200 will be specifically described. When the input shaft 52b of the low backlash gear device 200 of FIG. 6 is rotated to the left, torque is transmitted from the tooth surface 56b of the input gear 55b to the first intermediate output gear 35, and the first intermediate output gear 35 is disposed on the shaft. The first intermediate input gear 45 starts to rotate rightward. Next, the torque of the first intermediate input gear 45 is transmitted to the output gear 65 through the tooth surface 67 of the output gear 65, and the output gear 65 and the output shaft 62 are rotated to the left. That is, when the input shaft 52b is rotated to the left, the torque is immediately transmitted to the output shaft 62. Further, the torque transmitted to the output gear 65 is transmitted from the tooth surface 66 of the output gear 65 to the main gear 15b as the torque in the right rotation direction, but the torque in the right rotation direction is given to the sub-gear 25b, and the input gear is input. The 55b is rotated to the left, so that the disc spring 16b is not compressed, and the main gear 15b and the sub-gear 25b are rotated rightward in a driven manner. In other words, since the backlash is rotated in a state where the backlash is small, even if the state input shaft 52b is stopped, the state in which the backlash is small is maintained.

On the other hand, in the case where the input shaft 52b of FIG. 6 is rotated rightward, the right side of the input gear 55b rotates from the tooth surface 57b of the input gear to the auxiliary tooth. The wheel 25b transmits torque. As a result of the torque transmitted to the sub-gear 25b, as shown in Fig. 5, the ball 24 moves in a direction to be released from the groove 18a, and the disc spring 16b (the coil spring 16a in Fig. 5) is compressed by the driven plate 18. Next, as shown in FIG. 7, the tooth surface 57b of the input gear 55b is in contact with the first intermediate output gear 35, and the input gear 55b also starts transmitting torque to the first intermediate output gear 35. Thus, the torque from the input gear 55b is transmitted to the output gear 65 through the first intermediate gear 30 and the low backlash gear 10b. Further, before the tooth surface 57b of the input gear 55b comes into contact with the first intermediate output gear 35, the autonomous gear 15b is balanced when the torque applied to the auxiliary gear 55b from the input gear 55b is equalized to the reaction force of the disk spring 16b. Torque is transmitted to the output gear 65. That is, in either case, torque is transmitted from the input shaft 52b to the output shaft 62 in a state where the disk spring 16b of the low backlash gear mechanism 10b is compressed. Therefore, when the input shaft 52b is stopped, the low backlash gear mechanism 10b is given a torque by the reaction force of the compressed disc spring 16b. At this time, the torque in the right rotation direction is given to the sub-gear 25b, and the input gear 55b is rotated to the left by the tooth surface 57b of the input gear 55b. Further, when the input shaft 52b is directly coupled to the motor, the input shaft 52b is fixed so as not to rotate due to the servo lock of the motor, so that the sub gear 25b and the input gear 55b that is in contact therewith do not rotate. On the other hand, the output gear 65 is rotated right by the torque applied to the left rotation direction of the main gear 15b, and the torque is transmitted from the tooth surface 67 of the output gear 65 to the first intermediate input gear 45 and the first intermediate input gear. 45 left rotation. Next, the first intermediate output gear 35 on the shaft is also rotated to the left to come into contact with the tooth surface 56b of the input gear 55b. At this time, the low backlash gear device 200 is completely stopped. So low backlash The gear unit 200 automatically returns to the state shown in Fig. 6, that is, the state in which the backlash is small.

Fig. 8(a) shows the reduction gear unit 300 incorporated in the low backlash gear mechanism 10b. As shown in FIG. 8(b), the first intermediate gear 30 and the second intermediate gear, that is, the low backlash gear mechanism 10b, are arranged side by side, and the auxiliary gear 35b and the intermediate output gear 35 are partially overlapped in the axial direction. This simplifies the height and axial direction of the reduction gear 300.

As shown in FIG. 9, the motor M is coupled to the orthogonal gear 50, and a parallel gear 55c is provided on the input shaft 52c of the orthogonal gear 50. The parallel gear 55c meshes with the counter gear 25b of the low backlash gear mechanism 10b, and the main gear 15b is provided on the shaft 12b of the low backlash gear mechanism 10b, and the main gear 15b meshes with the output gear 65. Thus, by incorporating the low backlash gear mechanism 10b into the reduction gear unit 300, a reduction gear having a small backlash can be realized. Further, if the output gear 65 is a rack, it is possible to realize a rack gear having a small backlash. That is, the low backlash gear mechanism of the present invention can be applied to the gear that meshes with the parallel gear.

As described above, according to the low backlash gear mechanism of the present invention, the backlash can be reduced in either of the forward and reverse directions of the motor. Moreover, since the structure is simple, it can be easily assembled, and the mounting angle can be adjusted only by the screwing condition of the nut, and the magnitude of the torsional moment applied to the main gear and the sub-gear can be easily adjusted.

10‧‧‧Low backlash gear mechanism

10a‧‧‧Low backlash gear mechanism (output gear)

10b‧‧‧Low backlash gear mechanism (2nd intermediate gear)

12, 12b‧‧‧ axis

12a‧‧‧ Output shaft (input shafts in paragraphs 0028 and 0029)

14, 14a, 14b‧‧‧ nuts

15, 15a, 15b‧‧‧ main gear (intermediate input gear)

16, 16a, 16b‧‧‧ Elastomers

17‧‧‧Domed hole (set in the secondary gear)

18‧‧‧From the moving plate

18a‧‧‧V-shaped groove in the circumferential direction

24 ‧ ‧ ball

25, 25a, 25b‧‧‧ sub-gear (intermediate output gear)

26‧‧‧ screws

28‧‧‧ driven flange

28a‧‧‧Domed hole (set on driven flange)

28b‧‧‧ Viewing the elliptical long hole from the front

30‧‧‧1st intermediate gear

35‧‧‧Intermediate output gear

45‧‧‧Intermediate input gear

52a, 52b‧‧‧ input shaft (output shaft in paragraphs 00829 and 0029)

55a, 55b‧‧‧ input gears (output gears in paragraphs 00829 and 0029)

62‧‧‧ Output shaft

65‧‧‧ Output gear

100‧‧‧Low backlash gear unit

Fig. 1 is a front view showing a low backlash gear mechanism according to a first embodiment of the present invention.

Figure 2 is a cross-sectional view of the important portion of Figure 1 in the circumferential direction.

Fig. 3 is a front elevational view showing a state in which the second embodiment of the present invention is assembled into a one-stage gear.

Fig. 4 is an enlarged cross-sectional view showing an important part of the stop (assembly) of Fig. 3.

Fig. 5 is an enlarged cross-sectional view showing an important part of the rotation of Fig. 3.

Fig. 6 is a front elevational view showing a state in which the third embodiment of the present invention is assembled to a two-stage gear.

Figure 7 is a front view of the rotation of Figure 6 in a certain direction.

Fig. 8(a) is a front view showing a reduction gear according to the present invention, and Fig. 8(b) is a side sectional view showing an important part of Fig. 8(a).

Figure 9 is a cross-sectional view taken along line 9-9 of Figure 8.

10‧‧‧Low backlash gear mechanism

12‧‧‧Axis

14‧‧‧ Nuts

15‧‧‧ main gear

16‧‧‧ Disc spring

17‧‧‧Domed hole

18‧‧‧From the moving plate

18a‧‧‧ slot

24 ‧ ‧ ball

25‧‧‧Sub gear

55‧‧‧Other gears

56, 57‧‧‧ tooth surface

Claims (4)

A low backlash gear mechanism, comprising: a main gear coupled to a shaft; a sub gear rotatably disposed on the shaft and provided with at least one hemispherical hole; a ball fitted to the shaft The hemispherical hole; the driven plate is provided with a V-shaped groove of a circumferential cross section of the size of the ball fitable, coupled to the shaft and movable in the axial direction; a nut screwed into the shaft And an elastic body disposed between the nut and the driven plate; and the nut, the elastic body, the driven plate, the ball, the auxiliary gear, and the main gear are sequentially disposed from one end of the shaft; The driven plate is elasticized in a state where the deepest portion of the hemispherical hole into which the ball of the pin gear is fitted is displaced from the deepest portion of the groove in the rotational direction, and the ball is in contact with the inclined surface of one of the grooves. Push the body. The low backlash gear mechanism of claim 1, comprising a driven flange, wherein the driven flange is screwed to the auxiliary gear, and has at least one hemispherical hole into which the ball is fitted and used An elliptical long hole is observed from the front side by inserting the above screw. A low backlash gear device comprising an input gear or an output gear disposed on an input shaft or an output shaft and an output gear or an input gear having two gears disposed on the output shaft or the input shaft a gear of one of the output gear or the input gear is set as the main gear, and the other gear is set as the auxiliary gear, and the output gear is Or enter the gear to incorporate a low backlash gear mechanism as in item 1 or item 2 of the patent application. A low backlash gear device includes an input gear provided on an input shaft, an output gear provided on an output shaft, a first intermediate gear, and a second intermediate gear, wherein the first intermediate gear and the second intermediate gear are disposed on the input gear Between the output gear, an intermediate output gear that meshes with the input gear and an intermediate input gear that meshes with the output gear; and the intermediate input gear of the first intermediate gear or the second intermediate gear is the main gear or In the sub-gear, the intermediate output gear is the sub-gear or the main gear, and the low-backlash gear mechanism according to the first or second aspect of the patent application is incorporated in the first intermediate gear or the second intermediate gear.