JP5971901B2 - Motor with reduction mechanism - Google Patents

Description

  The present invention relates to a motor with a speed reduction mechanism.

  For example, in Patent Document 1, as shown in FIG. 5, a thrust bearing 113 is provided on both sides of a worm 112 that can slide freely in the direction of the rotation axis 111 of the motor 110, and the thrust bearing 113 and the inner side surface 114 of the housing case are provided. Describes a motor with a speed reduction mechanism in which a coil spring 115 (compression coil spring) for biasing the worm 112 in the direction of the rotating shaft 111 is arranged. In this motor with a speed reduction mechanism, when the worm wheel 116 meshed with the worm 112 is in a high load state with a high load, the switches 117 provided on both sides of the worm 112 are turned on by the movement of the worm 112 to detect the high load state. In addition, by stopping or reversely rotating the motor by a control circuit connected to the motor with a speed reduction mechanism, it is possible to prevent overcurrent from flowing through the motor and to prevent damage to the meshing portion between the worm and the worm wheel. .

Japanese Utility Model Publication No. 52-156873

  However, in the motor with a speed reduction mechanism shown in FIG. 5, the compression coil spring (elastic member) for biasing the worm is provided in contact with the thrust bearing and the inner side surface of the housing case. The elastic member is twisted to some extent in the rotational direction. Then, the urging force of the compression coil spring becomes unstable due to the torsion, and sliding wear occurs at either end of the compression coil spring, thereby reducing the durability of the compression coil spring and reducing the reliability of the device. End up. In addition, since thrust bearings are used, the cost of parts increases.

  Therefore, the present invention can prevent overcurrent from flowing through the motor, prevent damage to the meshing portion between the worm and the worm wheel, and further reduce the durability and reliability. An object of the present invention is to provide a motor with a mechanism.

The motor with a speed reduction mechanism according to claim 1 of the present invention, which is configured to achieve the above object,
A motor,
A rotating shaft protruding from one of the motors;
A worm mounted on the rotating shaft, capable of rotating integrally with the rotating shaft, and movable in the direction of the rotating shaft with respect to the rotating shaft;
A worm wheel meshed with the worm;
A stopper fixed to the rotating shaft;
An elastic member that has one end abutting against the stopper and the other end abutting against the worm to bias the worm in the direction of the rotation axis;
A detecting means for detecting movement of the worm in the direction of the rotation axis ;
The worm has a hollow portion radially inward,
The stopper and the entire elastic member are arranged in the cavity .

A motor with a speed reduction mechanism according to claim 2 of the present invention is the motor with a speed reduction mechanism according to claim 1 ,
The detection means is a switch operated by the movement of the worm.

The motor with a speed reduction mechanism according to claim 3 of the present invention is the motor with a speed reduction mechanism according to claim 1 or 2 ,
The detection means is a non-contact type sensor.

  In the motor with a speed reduction mechanism of the present invention, when the load state of the worm wheel meshing with the worm changes from a normal load state to a high load state with a high load, the worm compresses the elastic member in response to a reaction force from the worm wheel. The detection means detects a worm that has moved a predetermined distance, thereby detecting a high load state of the worm wheel. Then, the motor is stopped or reversely rotated based on the signal from the detection means, so that it is possible to prevent an overcurrent from flowing through the motor and to prevent the meshing portion between the worm and the worm wheel from being damaged. Further, when the rotating shaft rotates, the elastic member rotates integrally with the rotating shaft, so that the elastic member is not twisted or slipped in the rotating direction, thereby preventing a decrease in durability of the elastic member. At the same time, the urging force of the elastic member according to the design value stably acts on the worm over a long period of time, so that the durability and reliability of the apparatus can be enhanced.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure for demonstrating the motor with a reduction mechanism which concerns on the example of 1st Embodiment of this invention, (a) is a top view except the upper case of the motor with a reduction mechanism, (b) is (a) It is sectional drawing of cutting line AA of). BRIEF DESCRIPTION OF THE DRAWINGS It is a figure for demonstrating operation | movement of a worm concerning 1st Example of this invention, (a) is a top view except the upper case of the motor with a speed-reduction mechanism, (b) is (a). It is sectional drawing of the cutting line BB of). It is a figure for demonstrating the motor with a speed-reduction mechanism which concerns on 2nd Example of this invention, (a) is a top view except the upper case of the motor with a speed-reduction mechanism, (b) is (a) It is sectional drawing of the cutting line CC of). It is a figure for demonstrating the motor with a reduction mechanism which concerns on 3rd Example of this invention, (a) is a top view except the upper case of the motor with a reduction mechanism, (b) is (a) It is sectional drawing of the cutting line DD of FIG. It is sectional drawing of the motor with the conventional deceleration mechanism.

  Hereinafter, a motor with a speed reduction mechanism according to an embodiment of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a diagram for explaining a motor with a speed reduction mechanism according to a first embodiment of the present invention.
FIG. 2 is a diagram for explaining the operation of the worm according to the first embodiment of the present invention.

  As shown in FIG. 1, the motor 1 with a speed reduction mechanism of the present example includes a housing 10, a motor 20, a rotating shaft 21, a worm 22A, a worm wheel 27, a left stopper 31A, a right stopper 31B, and an elastic member. Members 40A and 40B and detection means 50A and 50B are provided.

  The housing 10 is formed in a box shape in which the opening ends of the upper case (not shown) and the lower case 11 are fitted to each other to have a predetermined internal space, and accommodates the motor 20, the worm wheel 27, and the like. The lower case 11 is provided with a motor support portion 11A that is integrally raised from the inner bottom surface.

  The motor 20 is composed of an inner rotor type brush motor, and is fixed to the motor support portion 11A by screws.

  The rotating shaft 21 protrudes from the motor case 20A of the motor 20 to one side, and the protruding portion is formed into an outer shape D-cut shape, and a worm 22A is attached to this D-cut shape portion.

  The worm 22A is formed of a hard resin and has a D-cut through hole 22A1 in the longitudinal direction. The through hole 22A1 is configured to be slightly larger than the outer shape of the rotating shaft portion protruding from the motor case 20A. When the worm 22A is attached (engaged) to the rotating shaft 21, the worm 22A is integrated with the rotating shaft 21. And can move in the direction of the rotation axis. Further, on both sides of the worm 22A in the rotation axis direction, a left cavity portion 24A and a right cavity portion 24B are provided radially inside, respectively, and the left cavity portion 24A and the right cavity portion 24B are circular when viewed from the rotation axis direction. Is formed.

  The worm wheel 27 is made of a hard resin and meshes with the worm 22A. The worm wheel 27 is sandwiched between the upper case and the lower case 11 and is rotatably provided.

  The left-side stopper 31A and the right-side stopper 31B are formed of a metal material in an outer circular shape, are respectively press-fitted and fixed to the rotary shaft 21, and limit the movement of the worm 22A in the rotary axis direction. The outer shapes of the left stopper 31A and the right stopper 31B are slightly smaller than the left cavity 24A and the right cavity 24B. The left stopper 31A is inserted into the left cavity 24A, and the right stopper 31B is inserted into the right cavity 24B.

The elastic members 40A and 40B are composed of compression coil springs and bias the worm 22A in the direction of the rotation axis. The elastic member 40A has one end in contact with the left stopper 31A and the other end in contact with the bottom of the left cavity 24A, and the entire elastic member 40A and left stopper 31A are disposed in the left cavity 24A. The elastic member 40B has one end in contact with the right stopper 31B and the other end in contact with the bottom of the right cavity 24B. The entire elastic member 40B and the right stopper 31B are disposed in the right cavity 24B. The outer shapes of the elastic members 40A and 40B are smaller than the outer shapes of the left stopper 31A and the right stopper 31B.
In addition, although the above-mentioned elastic member is a compression coil spring, cylindrical rubber | gum etc. may be sufficient.

If comprised in this way, while elastic member 40A will be in the state which urged worm | warm 22A to the rotating shaft direction (arrow T direction in FIG. 1), elastic member 40B will make worm 22A the rotating shaft direction (FIG. 1). It is in a state of being biased in the direction of arrow U in the middle.
Further, since the left stopper 31A is formed slightly smaller than the left cavity 24A and the right stopper 31B is formed slightly smaller than the right cavity 24B, the worm 22A is displaced by the elastic members 40A and 40B. Only in the direction of the rotation axis (direction of arrow U or arrow T in FIG. 1).
When the rotary shaft 21 is rotated by engaging the rotary shaft 21 and the through hole 22A1 of the worm 22A, the worm 22A, the elastic members 40A and 40B, the left stopper 31A, and the right stopper 31B are integrated with the rotary shaft. Rotate (synchronously).

  The detection means 50A and 50B are non-contact type sensors constituted by transmissive photo interrupters, and detect the movement of the worm 22A. The transmissive photointerrupter of this example is arranged so that the light emitting elements 50A1 and 50B1 and the light receiving elements 50A2 and 50B2 are opposed to each other with a certain interval across the worm 22A in a direction perpendicular to the rotation axis direction. The detection means 50A is disposed in close proximity to the left end 26A of the worm, and the detection means 50B is disposed in close proximity to the right end 26B of the worm. When the worm 22A moves in the rotation axis direction, the light from the light emitting element is blocked by the worm 22A, and the detection means 50A and 50B detect the movement of the worm 22A in the rotation axis direction.

In the motor 1 with a speed reduction mechanism of this example configured as described above, when a drive current is supplied to the motor 20 and the motor 20 is driven, the rotating shaft 21 rotates (forward or reverse), and the worm 22A is illustrated. 1 rotates clockwise or counterclockwise when viewed from the front end side of the rotating shaft. Then, the worm wheel 27 meshed with the worm 22A rotates in the arrow R direction or the arrow S direction in FIG.
Further, when the motor 20 is driven, one of the light emitting element 50A1 and the light emitting element 50B1 emits light according to the rotation direction of the motor. Specifically, when the motor rotates so that the worm wheel 27 rotates in the direction of arrow R in FIG. 1, the light emitting element 50A1 emits light, and the worm wheel 27 rotates in the direction of arrow S in FIG. When the motor rotates, the light emitting element 50B1 is controlled to emit light.

When the load state of the worm wheel 27 changes from the normal load state to the high load state with a high load, the worm 22A receives the reaction force from the worm wheel 27 and compresses the elastic member to rotate in the direction of the rotation axis (FIG. 1). Move in the direction of arrow U or arrow T).
FIG. 2 shows a state when the worm wheel 27 is changed to a high load state while rotating in the arrow R direction. As shown in FIG. 2, when the worm 22A moves a predetermined distance due to a high load state of the worm wheel 27, the light from the light emitting element 50A1 is blocked by the worm 22A, and the light receiving element 50A2 cannot receive the light from the light emitting element 50A1. Thus, the high load state of the worm wheel can be detected. Then, the motor is stopped or reversely rotated based on this detection signal, so that it is possible to prevent an overcurrent from flowing through the motor and to prevent the meshing portion between the worm and the worm wheel from being damaged.

Further, the motor 1 with a speed reduction mechanism of the present example is mounted on a rotating shaft 21, a worm 22 </ b> A that can rotate integrally with the rotating shaft 21 and move in the rotating shaft direction, and stoppers 31 </ b> A and 31 </ b> B fixed to the rotating shaft 21. , Elastic members 40A, 40B that abut one end against the stoppers 31A, 31B and the other end abut against the worm 22A to urge the worm 22A in the direction of the rotation axis, and detecting means for detecting movement of the worm 22A in the direction of the rotation axis 50A and 50B are provided.
Therefore, when the rotation shaft rotates (forward rotation or reverse rotation), the elastic member (compression coil spring) rotates integrally (synchronously) with the rotation shaft. Therefore, the elastic member is twisted or slipped in the rotation direction. Since it does not occur, the durability of the elastic member can be prevented from decreasing, and the urging force of the elastic member according to the design value stably acts on the worm over a long period of time. It is possible to stably detect the high load state of the device and prevent deterioration of the durability and reliability of the device.
Further, in the motor with the speed reduction mechanism of this example, the worm is urged in the direction of the rotation axis without using the thrust bearing as in the conventional example, so that the cost can be reduced.

In the motor with a speed reduction mechanism of this example, the entire elastic member 40A and the left stopper 31A are arranged in the left cavity 24A, and the entire elastic member 40B and the right stopper 31B are in the right cavity 24B. It is arranged in.
With this configuration, the mounting width of the elastic member and worm in the rotation axis direction (the total length of the elastic member and worm in the rotation axis direction when the elastic member and worm are mounted on the rotation shaft) can be minimized. The device can be miniaturized.

  Further, in the motor with a speed reduction mechanism of this example, since the detection means 50A and 50B are non-contact type sensors, the high load state of the worm wheel can be detected without contact between the worm and the detection means. It can be remarkably improved.

In the motor with a speed reduction mechanism of this example, a cavity is provided in the worm and the elastic member is completely accommodated in the cavity. However, in the present invention, at least a part of the elastic member in the axial direction is the cavity of the worm. If it is inserted into the part, the mounting width of the elastic member and the worm in the direction of the rotation axis can be suppressed, and the apparatus can be prevented from being enlarged.
In the motor with a speed reduction mechanism of the present invention, the elastic member can be disposed in contact with the end of the worm without providing the cavity with the cavity. In this case, although there is no merit of downsizing the apparatus, the shape of the worm is simplified and the manufacturing cost can be reduced.

  Further, in the motor with a speed reduction mechanism of this example, a non-contact sensor composed of a transmissive photo interrupter is used as a detection means. As this non-contact sensor, for example, a reflective photo interrupter including a light emitting element and a light receiving element is used. It can also be used. In the case of using a reflection type photo interrupter, for example, a reflection plate is provided on the outer periphery of both ends of the worm. When the worm moves a predetermined distance due to the high load state of the worm wheel, the light from the light emitting element is reflected by the reflecting plate, and the light receiving element receives the reflected light, whereby the high load state of the worm wheel can be detected.

  In the motor with a speed reduction mechanism of the present invention, the detection means 50A and 50B are not limited to the non-contact type sensor as described above, but are contact type leaf switches and push buttons that are operated (pressed) by the movement of the worm 22A. A switch or a microswitch may be used. The switch in this case is arranged to face the end of the worm.

  Further, in the motor with a speed reduction mechanism of this example, the worm 22A is urged in both directions of the rotating shaft using the two elastic members 40A and 40B, and the movement of the worm 22A in both directions is detected by the two detection means 50A and 50B. For example, when the driving direction of the motor is only one direction (that is, in the case of a device that rotates the worm wheel 27 only in one direction of arrow R or arrow S in FIG. 1). The urging and movement detection of the worm 22A may be performed in only one direction according to the driving direction (rotation direction).

Specifically, in the case of a device that rotates the worm wheel 27 only in the direction of arrow R in FIG. 1, in order to detect a high load state of the worm wheel 27, the worm 22A is attached in the direction of arrow T in FIG. In the configuration shown in FIG. 1, the stopper 31B except for the elastic member 40B is disposed in contact with the bottom of the right cavity 24B to detect the movement in the arrow U direction. Is removed. In this case, when the detection means 50A detects that the worm 22A has moved a predetermined distance in the direction of the arrow U in FIG. 1 and detects the high load state of the worm wheel, the motor is detected based on this detection signal. Stopped. As a result, it is possible to prevent an overcurrent from flowing through the motor and to prevent damage to the meshing portion between the worm and the worm wheel.
In the case of a device that rotates the worm wheel 27 only in the direction of arrow S in FIG. 1, in order to detect a high load state of the worm wheel 27, the worm 22A is urged in the direction of arrow U in FIG. Therefore, in the configuration of FIG. 1, the stopper 31A is arranged in contact with the bottom of the left cavity 24A except for the elastic member 40A, and the detecting means 50A is removed. . In this case, when the detection means 50B detects that the worm 22A has moved a predetermined distance in the direction of the arrow T in FIG. 1 and detects a high load state of the worm wheel, the motor is detected based on this detection signal. Stopped. As a result, it is possible to prevent an overcurrent from flowing through the motor and to prevent damage to the meshing portion between the worm and the worm wheel.

(Second Embodiment)
FIG. 3 is a view for explaining a motor with a speed reduction mechanism according to a second embodiment of the present invention, and FIG. 3 (a) is a plan view excluding an upper case of the motor with a speed reduction mechanism. 3 (b) is a cross-sectional view taken along the section line CC in FIG. 3 (a). In FIG. 3, the same reference numerals as those in FIG. 1 denote the same members, and detailed description thereof is omitted.

The motor with a speed reduction mechanism of this example is configured to detect movement only in the direction of the arrow U in a state where the worm 22B is urged only in the direction of the arrow T in FIG. 3, and the elastic member 40B in FIG. The detection means 50B is omitted and the stopper structure is different from that of the first embodiment.
That is, in the first embodiment, the right stopper 31B is provided in the right cavity portion 24B of the worm 22A, but in this example, the right end of the worm 22B is closed, and on the right side of the closed portion is a rotating shaft. A hemispherical projection 22B1 projecting in the direction is provided, and the projection 22B1 is disposed in contact with the inner surface of the lower case 11, thereby moving the worm 22B in the direction of the rotation axis (in the direction of arrow T in FIG. 3). ) Is restricted.

  A gap is provided between the tip of the rotating shaft 21 and the closed portion of the worm 22B (the bottom of the insertion hole 22B2) so that the worm 22B can move in the direction of the rotating shaft (the direction of the arrow U in FIG. 3). ing.

In the motor with a speed reduction mechanism of this example, when the motor 20 is driven, the worm wheel 27 rotates in the direction of arrow R in FIG. When the detection means 50A detects that the worm 22B has moved a predetermined distance in the direction of arrow U in FIG. 3 and detects a high load state of the worm wheel, the motor is stopped based on this detection signal. As a result, it is possible to prevent an overcurrent from flowing through the motor and to prevent damage to the meshing portion between the worm and the worm wheel.
When the rotating shaft rotates, the elastic member 40A rotates integrally (synchronously) with the rotating shaft, so that the elastic member 40A is not twisted or slipped in the rotating direction. As a result, the durability of the elastic member can be prevented from being lowered, and the urging force of the elastic member according to the design value stably acts on the worm over a long period of time. High load conditions can be detected stably, and deterioration of device durability and reliability can be prevented.
In addition, the motor with a speed reduction mechanism of this example can also realize cost reduction because the worm is urged in the direction of the rotation axis without using a thrust bearing as in the conventional example.

(Third embodiment)
FIG. 4 is a view for explaining a motor with a speed reduction mechanism according to a third embodiment of the present invention. FIG. 4 (a) is a plan view excluding an upper case of the motor with a speed reduction mechanism. 4 (b) is a cross-sectional view taken along a cutting line DD in FIG. 4 (a). In FIG. 4, the same reference numerals as those in FIGS. 1 and 3 indicate the same members, and detailed description thereof is omitted.

  This example is different from the second embodiment in the structure of the motor. In the second embodiment, it is configured by an inner rotor type brushed motor 20, but in this example, it is configured by an outer rotor type brushless motor 28.

More specifically, the brushless motor 28 of this example has a rotor 28B on the outer periphery of the stator.
The stator has a stator core (not shown) fixed to the stator base 28A and wound, and the stator base 28A is fixed to the left inner wall portion 11B of the lower case 11.
The rotor 28B has a rotor case 28B1 and a rotating shaft 29 arranged on the outer periphery of the stator core.

The rotating shaft 29 is fixed to the rotor case 28B1 of the rotor 28B and protrudes from the rotor case 28B1 to one side. The protruding portion is formed in an outer shape D-cut, and the worm 22B is formed in the D-cut portion. Mounted (engaged).
The elastic member 40C that urges the worm 22B has one end in contact with the rotor case 28B1 and the other end in contact with the bottom of the left cavity 24A. The worm 22B is moved in the direction of the rotation axis (the direction of arrow T in FIG. 4). Energize.
When the rotating shaft 29 rotates, the worm 22B, the elastic member 40C, and the rotor case 28B1 rotate integrally (synchronously) with the rotating shaft, and the worm 22B rotates in the direction of the rotating shaft by the amount of displacement of the elastic member 40C (FIG. 4). In the direction of arrow U).

  In the motor with a speed reduction mechanism of this example, when the brushless motor 28 is driven, the worm wheel 27 rotates in the direction of arrow R in FIG. In the case of the motor with a speed reduction mechanism of this example, when the detection means 50A detects that the worm 22B has moved a predetermined distance in the direction of arrow U in FIG. 4 and detects the high load state of the worm wheel 27, this detection signal Based on this, the motor is stopped. As a result, it is possible to prevent an overcurrent from flowing through the motor and to prevent damage to the meshing portion between the worm and the worm wheel.

Further, when the rotating shaft rotates, the elastic member 40C rotates integrally with the rotating shaft, so that the elastic member 40C is not twisted or slipped in the rotating direction, so that the durability of the elastic member can be prevented from being lowered. At the same time, the urging force of the elastic member according to the design value acts on the worm stably over a long period of time, so the high load state of the worm wheel can be detected stably with the worm movement amount as the design value, and the durability of the device Deterioration of reliability and reliability can be prevented.
In addition, the motor with a speed reduction mechanism of this example can also realize cost reduction because the worm is urged in the direction of the rotation axis without using a thrust bearing as in the conventional example.
In addition, since a non-contact type sensor is used as the detection means and a brushless motor is used as the motor, a motor with a reduction mechanism having high durability and reliability can be realized.
In each of the three embodiments of the present invention described above, the worm wheel meshing with the worm is the output gear, but one or more reduction gears are arranged between the worm and the worm wheel. May be.

Next, as a usage example of the motor with a speed reduction mechanism of the present invention, a case where the motor with a speed reduction mechanism of the first embodiment of the present invention is used in a power window device for an automobile will be described. A typical automotive power window device uses rotational forces in both directions (in the direction of arrow S and arrow R in FIG. 1) of the output shaft of the motor with a speed reduction mechanism (the axis of the worm wheel 27 in the example of FIG. 1). Thus, the window glass is moved in the vertical direction.
When the load state of the worm wheel is a normal load state in which the window glass moves smoothly, the worm rotates while receiving the reaction force from the worm wheel and slightly compressing the elastic member to move in the direction of the rotation axis. When the load state of the worm wheel changes from a normal load state to a high load state where a person or an object is sandwiched between, for example, a window glass, the worm receives a reaction force from the worm wheel to increase the elastic member. The detection means detects the worm that has been moved a predetermined distance by detecting the worm that has been moved by a predetermined distance, and detects the high load state of the worm wheel. The motor is stopped or reversely rotated by a control circuit (not shown) connected to the detecting means, so that overcurrent can be prevented from flowing through the motor, and the meshing portion between the worm and the worm wheel can be prevented. Can prevent damage.

A case will be described in which the motor with a speed reduction mechanism according to the second embodiment or the third embodiment of the present invention is used in a wiper driving device for an automobile. A general wiper driving device for an automobile uses a motor with a speed reduction mechanism in combination with a mechanism that converts a rotational movement in one direction of the motor into a swinging reciprocating motion. In the example of FIG. 4, the wiper attached to the windshield or rear glass is swung by using the rotational force in one direction (the direction of arrow R in FIGS. 3 and 4) of the worm wheel 27 axis. .
When the load state of the worm wheel is a normal load state in which the wiper swings smoothly, the worm rotates while moving in the direction of the rotation axis by slightly compressing the elastic member in response to the reaction force from the worm wheel. When the load state of the worm wheel changes from a normal load state to a high load state with a high load in which snow, mud, or the like accumulates on the glass, the worm receives a reaction force from the worm wheel and greatly compresses the elastic member. The detection means detects a worm that has moved a predetermined distance, thereby detecting a high load state of the worm wheel. Then, by stopping the motor by a control circuit (not shown) connected to the detection means, it is possible to prevent an overcurrent from flowing through the motor, and to prevent the meshing portion between the worm and the worm wheel from being damaged.

DESCRIPTION OF SYMBOLS 1 Motor with reduction mechanism 10 Housing 11 Lower case 11A Motor support part 11B Left inner wall part (motor support part) of lower case
20 motor 20A motor case 21 rotating shaft 22A worm 22A1 through hole 22B worm 22B1 protrusion 22B2 insertion hole 22C worm 24A left cavity 24B right cavity 26A left end 26B right end 27 worm wheel 28 rotor base 28 rotor B Case 29 Rotating shaft 31A Left side stopper 31B Right side stopper 40A Elastic member (compression coil spring)
40B Elastic member (compression coil spring)
40C elastic member (compression coil spring)
50A detection means (transmission type photo interrupter)
50A1 Light emitting element 50A2 Light receiving element 50B Detection means (transmission type photo interrupter)
50B1 Light emitting element 50B2 Light receiving element

Claims (3)

A motor,
A rotating shaft protruding from one of the motors;
A worm mounted on the rotating shaft, capable of rotating integrally with the rotating shaft, and movable in the direction of the rotating shaft with respect to the rotating shaft;
A worm wheel meshed with the worm;
A stopper fixed to the rotating shaft;
An elastic member that has one end abutting against the stopper and the other end abutting against the worm to bias the worm in the direction of the rotation axis;
A detecting means for detecting movement of the worm in the direction of the rotation axis;
The worm has a hollow portion radially inward,
A motor with a speed reduction mechanism, wherein the stopper and the entire elastic member are disposed in the cavity. The motor with a speed reduction mechanism according to claim 1, wherein the detection means is a switch operated by the movement of the worm. The motor with a speed reduction mechanism according to claim 1 or 2, wherein the detection means is a non-contact type sensor.

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