JP2019058033A - Geared motor - Google Patents

Abstract

To provide a geared motor capable of preventing the geared motor from being in an inoperable state and from generating a strange sound in a case where a force is applied from a load side.SOLUTION: A geared motor 1 comprises: a motor 10; a worm 30 coupled with a rotation shaft 13 of the motor 10; a worm wheel 41 engaged with a tooth part 31 of the worm 30; and a stopper 60 provided at an opposite side to the worm wheel 41 with the worm 30 interposed therebetween. The stopper 60 is arranged so that a predetermined interval is formed from a worm front end part 34 extending from the tooth part 31 of the worm 30 toward the front end side.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a geared motor, and more particularly to a geared motor in which a worm gear is attached to a rotating shaft of the motor.

  Conventionally, a geared motor is known in which a worm gear is attached to a rotating shaft of a motor so as to obtain a high reduction ratio (see, for example, Patent Document 1). This type of worm gear is composed of a worm coupled to a rotating shaft of a motor and a worm wheel meshing with the worm. Generally, such a worm gear is a motor from the load side (worm wheel). It has the characteristic that it is difficult to rotate the rotating shaft (worm). Such characteristics are also called self-locking.

  When this self-lock occurs, that is, when a force for rotating the worm from the load side (worm wheel) is applied, a side pressure is generated that pushes the tooth surface of the worm from the worm wheel. Therefore, when the rotating shaft of the motor is thin and the strength is low, the rotating shaft and the worm are deflected to the opposite side of the worm wheel by this side pressure. If the worm is bent in this manner, the worm wheel may bite into the tooth surface of the worm, and the worm cannot rotate in either direction, and the motor may not be driven. Even if the worm can rotate, if the worm or worm wheel is damaged, this may cause abnormal noise.

JP 2009-89492 A

  The present invention has been made in view of the above-described problems of the prior art, and provides a geared motor capable of preventing inoperability and abnormal noise from being generated when force is applied from the load side. With the goal.

  ADVANTAGE OF THE INVENTION According to the aspect of this invention, when a force is applied from the load side, the geared motor which can prevent becoming inoperable or generating an abnormal noise is provided. The geared motor includes a motor, a worm coupled to the rotation shaft of the motor, a worm wheel meshing with a tooth portion of the worm, and a stopper provided on the opposite side of the worm wheel with the worm interposed therebetween. . The stopper is disposed so that a predetermined interval is formed between the worm tip portion of the worm and the worm tip portion extending from the tooth portion toward the tip side.

  With such a configuration, a stopper is provided on the opposite side of the worm wheel across the worm, so that even if a force is applied to the worm from the worm wheel on the load side to rotate the worm, It is possible to regulate the range until it comes into contact with the stopper. Therefore, it is possible to prevent the worm and the rotation shaft of the motor from being excessively bent, and it is possible to prevent the worm wheel from getting into the tooth surface of the worm and becoming inoperable or generating abnormal noise. .

  The geared motor may further include a gear box attached to the motor. In this case, it is preferable that the worm and the worm wheel are accommodated in the gear box, and the stopper is configured to protrude from the inner surface of the gear box toward the worm.

  The stopper is preferably attached to the gear box so that the distance between the worm tip and the stopper can be changed. In this way, by configuring so that the distance between the worm tip and the stopper can be changed, the distance between the worm tip and the stopper can be maintained regardless of variations in the dimensions of the components of the geared motor and assembly errors during assembly. Can be adjusted to an appropriate interval.

  Furthermore, it is preferable that the geared motor further includes a fixing mechanism that fixes the position of the stopper with respect to the gear box. With such a fixing mechanism, the stopper can be fixed to the gear box after changing the distance between the worm tip and the stopper.

  According to the present invention, even if a force for rotating the worm wheel on the load side with respect to the worm acts, it is possible to prevent the worm and the rotation shaft of the motor from being excessively bent, and the worm wheel has a worm tooth. It is possible to prevent the sound from getting into the surface and becoming inoperable or generating abnormal noise.

FIG. 1 is a perspective view showing a geared motor according to an embodiment of the present invention. FIG. 2 is an exploded perspective view of the geared motor of FIG. FIG. 3 is a partially enlarged longitudinal sectional view of the geared motor of FIG.

  Hereinafter, embodiments of a geared motor according to the present invention will be described in detail with reference to FIGS. 1 to 3. 1 to 3, the same or corresponding components are denoted by the same reference numerals, and redundant description is omitted. Further, in FIGS. 1 to 3, there are cases where the scales and dimensions of each component are exaggerated and some components are omitted.

  FIG. 1 is a perspective view showing a geared motor 1 according to an embodiment of the present invention. As shown in FIG. 1, the geared motor 1 includes a motor 10 and a gear box 20 attached to the motor 10. The gear box 20 in the present embodiment is composed of gear cases 21 and 22 divided into two.

  FIG. 2 is an exploded perspective view of the geared motor 1. As shown in FIG. 2, a flange 12 is fixed to the end surface of the motor 10 on the + X direction side by a screw 11, and the two gear cases 21 and 22 are screwed so as to sandwich the flange 12 and the motor 10 in the Y direction. 23 and 23 are fixed. A housing space for housing a gear mechanism, which will be described later, is formed inside these gear cases 21 and 22 (gear box 20).

  FIG. 3 is a partially enlarged cross-sectional view of the geared motor 1, and only some components are shown in cross section for easy understanding. As shown in FIG. 3, the rotating shaft 13 of the motor 10 extends through the flange 12 in the + X direction, and a worm 30 is connected to the tip of the rotating shaft 13. The worm 30 is accommodated in the accommodating space S in the gear box 20.

  As shown in FIG. 2, the first compound gear 40 and the second compound gear 50 are accommodated in the accommodating space S in the gear box 20. The first compound gear 40 is attached to a shaft portion 24 provided in the gear case 22, and can rotate around the shaft portion 24. The second compound gear 50 is disposed between the gear case 21 and the gear case 22 and is rotatable about the shaft portion 25 of the gear case 21 and the shaft portion 26 of the gear case 22 formed on the same axis. ing.

  The worm 30 has a screw-like tooth portion 31. The first compound gear 40 includes a worm wheel 41 that meshes with the tooth portion 31 of the worm 30, and an intermediate gear 42 that is positioned coaxially with the worm wheel 41. The second compound gear 50 includes an intermediate gear 51 that meshes with the intermediate gear 42 of the first compound gear 40, and an output gear 52 that is positioned coaxially with the intermediate gear 51. As shown in FIG. 1, the output gear 52 at the final stage is exposed from a window 27 (see FIG. 2) formed in the gear case 21.

  When the rotating shaft 13 of the motor 10 is rotated by such a gear mechanism, the worm 30 is rotated together with the rotating shaft 13, and the rotation of the worm 30 is caused by the rotation of the worm wheel 41, the intermediate gear 42, the intermediate gear 51, and the output gear 52. Are transmitted sequentially. Thus, by using the worm gear composed of the worm 30 and the worm wheel 41, a high reduction ratio can be obtained.

  As shown in FIGS. 2 and 3, a light shielding plate 32 in which a plurality of holes are formed along the circumferential direction is formed integrally with the worm 30 between the tooth portion 31 of the worm 30 and the flange 12 of the motor 10. Is formed. Two photo interrupters 33 and 33 are attached to the gear case 22 so as to straddle the light shielding plate 32. The rotational speed of the light shielding plate 32 can be detected by these photo interrupters 33 and 33.

  As shown in FIG. 3, a leaf spring 35 that extends toward the accommodation space S in the gear box 20 is provided on the side surface of the gear case 22. The leaf spring 35 is disposed so as to contact a worm tip 34 extending from the tooth portion 31 of the worm 30 toward the tip, and biases the worm 30 toward the motor 10.

  As shown in FIG. 3, a plate-like stopper 60 is provided on the opposite side of the worm wheel 41 across the worm 30, that is, on the −Z direction side of the worm 30. The stopper 60 projects in the + Z direction from the inner surfaces of the gear cases 21 and 22 toward the worm 30, and the + Z direction end 61 of the stopper 60 faces the worm tip 34 of the worm 30. A predetermined gap (for example, about 0.1 mm) is formed between the end portion 61 in the + Z direction of the stopper 60 and the worm tip portion 34.

  As described above, when a force for rotating the load side worm wheel 41 with respect to the worm 30 is applied, the rotary shaft 13 and the worm 30 may bend in the −Z direction by the side pressure applied to the worm 30. However, in the present embodiment, since the stopper 60 is provided on the −Z direction side of the worm 30, the worm tip 34 comes into contact with the stopper 60 when the worm 30 bends in the −Z direction. Therefore, the worm 30 is not bent any more, and the bending of the worm 30 and the rotary shaft 13 is suppressed. As described above, according to the present embodiment, even if a force for rotating the load side worm wheel 41 with respect to the worm 30 is applied, the worm 30 and the rotating shaft 13 are not excessively bent. It is possible to prevent 41 from biting into the tooth surface of the worm 30 and becoming inoperable or generating abnormal noise.

  In order to suppress such bending of the worm 30 and the rotating shaft 13, it may be possible to support the worm tip 34 of the worm 30 with a bearing or the like. This is not only a problem, but also the structure becomes complicated, and a space for bearings and the like is required, so that downsizing becomes difficult. On the other hand, in this embodiment, since the bending of the worm 30 and the rotating shaft 13 can be suppressed by the stopper 60 having a simple structure, such a problem does not occur.

  By the way, the components of the geared motor 1 have dimensional variations, and an assembly error occurs during assembly. Therefore, when the stopper 60 is fixedly attached to the gear box 20, the distance between the stopper 60 and the worm tip 34 is too narrow depending on the product, and the stopper 60 is not moved when the motor 10 is driven. The contact with the portion 34 may cause friction loss and noise, or the distance from the worm tip 34 may be too wide to obtain the above-described effect of suppressing the bending of the worm 30. Conceivable. Therefore, in the present embodiment, when the geared motor 1 is assembled, the distance between the worm tip 34 and the stopper 60 is changed to an appropriate value (for example, about 0.1 mm), and the stopper 60 is fixed to the gear box 20. It is configured to be able to. Hereinafter, this configuration will be described.

  As shown in FIG. 2, a through hole 28 that penetrates the gear case 22 in the Z direction is formed at the bottom of the gear case 22. The stopper 60 has a size and shape that can be inserted into the through hole 28, and the position of the stopper 60 in the Z direction can be adjusted within the through hole 28. Thus, by adjusting the position of the stopper 60 in the Z direction within the through hole 28, the distance between the worm tip 34 and the stopper 60 can be changed. The through hole 28 may be formed across the gear case 21 and the gear case 22.

  Further, a screw hole 29 communicating with the above-described through hole 28 is formed on the side wall of the gear case 22, and a screw 70 is screwed into the screw hole 29. As shown in FIG. 3, by screwing the screw 70 into the screw hole 29, the stopper 60 inserted into the through hole 28 can be pressed against the inner wall of the through hole 28 by the tip of the screw 70. Accordingly, the stopper 60 can be fixed to the gear case 22 by fixing the position of the stopper 60 in the Z direction. As described above, the screw 70 and the screw hole 29 in the present embodiment serve as a fixing mechanism that fixes the position of the stopper 60 with respect to the gear case 22. Such a fixing mechanism is not limited to a screw and a screw hole, and any mechanism such as a mechanism that fixes the position of the stopper 60 by engagement can be used.

  With such a configuration, when the geared motor 1 is assembled, the position of the stopper 60 in the Z direction in the through hole 28 is adjusted, and the distance between the worm tip 34 and the stopper 60 is set to an appropriate value (for example, 0.1 mm). The stopper 60 can be fixed in the through hole 28 by screwing the screw 70 into the screw hole 29 in this state. Therefore, the distance between the worm tip 34 and the stopper 60 can be adjusted to an appropriate value regardless of variations in dimensions of components of the geared motor 1 and assembly errors during assembly.

  In the above-described embodiment, as shown in FIG. 2, the stopper 60 is a rectangular plate-like member. However, if the above-described bending of the rotating shaft 13 and the worm 30 can be suppressed, the stopper 60 is used. There are no particular restrictions on the shape and dimensions. For example, the stopper 60 may have a rod shape.

  In the above-described embodiment, the leaf spring 35 that contacts the worm tip 34 and the stopper 60 that is provided on the opposite side of the worm wheel 41 with the worm 30 interposed therebetween are configured separately. And the stopper 60 may be integrally formed, and the stopper 60 may be provided with a function of urging the worm 30 toward the motor 10.

  The preferred embodiments of the present invention have been described above, but the present invention is not limited to the above-described embodiments, and it goes without saying that the present invention may be implemented in various forms within the scope of the technical idea.

DESCRIPTION OF SYMBOLS 1 Geared motor 10 Motor 11 Screw 12 Flange 13 Rotating shaft 20 Gear box 21, 22 Gear case 23 Screw 24-26 Shaft part 27 Window 28 Through-hole 29 Screw hole 30 Worm 31 Tooth part 32 Light-shielding plate 33 Photo interrupter 34 Warm tip part 35 Leaf spring 40 First compound gear 41 Worm wheel 42 Intermediate gear 50 Second compound gear 51 Intermediate gear 52 Output gear 60 Stopper 70 Screw S Storage space

Claims (4)

A motor,
A worm coupled to the rotating shaft of the motor;
A worm wheel meshing with a tooth portion of the worm;
A stopper provided on the opposite side of the worm wheel with the worm interposed therebetween, and is disposed so that a predetermined interval is formed between the worm tip portion extending from the tooth portion to the tip side of the worm. A geared motor comprising a stopper. A gearbox attached to the motor;
The worm and the worm wheel are housed in the gearbox;
The stopper is configured to protrude from the inner surface of the gear box toward the worm.
The geared motor according to claim 1.   The geared motor according to claim 2, wherein the stopper is attached to the gear box so that a distance between the worm tip and the stopper can be changed.   The geared motor according to claim 3, further comprising a fixing mechanism that fixes a position of the stopper with respect to the gear box.

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