JPH09191608A - Geared motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the unstable element of brake force by fixing an endless spacer, as a locking member, to the inner wall of casing and providing a protrusion for generating a brake force on the surface abutting the end face of motor shaft. SOLUTION: An endless spacer 17 is provided, on the pressure abutting surface 17c, with a protrusion 17d for determining a brake force. The protrusion 17d has arcuate shape surrounding the axis of a motor shaft 6 and a plurality of protrusion 17d are juxtaposed in the circumferential direction at a predetermined interval. At the time of applying grease to the pressure abutting surface 17c of endless spacer 17 in order to stabilize the abrasion of protrusion 17d, the grease can flow out through the gap between protrusions 17d when it is compressed or expanded due to abrasion of the protrusion 17d or frictional heat. Consequently, abrupt drop of brake force due to compression or expansion of grease can be avoided surely when the grease is enclosed in the protrusion 17d and a stabilized brake force can be generated constantly regardless of the external force.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor with a speed reduction mechanism used for a power window device of an automobile.

[0002]

2. Description of the Related Art In general,
This type of motor with a speed reduction mechanism uses a worm gear mechanism with a reverse rotation prevention function to reduce the speed, so it is possible to prevent reverse rotation due to external force to some extent, but if a large reverse rotation force acts, the reverse rotation of the worm gear mechanism is prevented. There is a risk that the reverse rotation cannot be prevented only by the function. Therefore, when used in a power window device or the like that requires security, a reverse rotation prevention mechanism is separately installed in the worm gear mechanism to surely prevent the motor from reverse rotation due to external force. Is provided. However, the conventional reverse rotation preventing mechanism has disadvantages such as a large number of parts and a poor assembly property. Therefore, Japanese Patent Application Laid-Open No. 61-36
No. 476, an end spacer for generating a braking force (frictional force) by receiving a thrust force acting on the motor shaft and pressing the end surface of the motor shaft on which the worm is formed to press and contact the inner wall of the casing. It has been proposed to provide However, in this structure, since the end spacer is provided on the end surface of the motor shaft, and the convex portion that determines the braking force is formed on the pressing contact surface to the casing, the convex portion is formed in a ring shape. When grease is applied to the convex portion to stabilize the friction of No. 3, there is a drawback that the applied grease makes the braking force unstable. That is, since the grease is sealed in the ring-shaped convex portion, there is no escape even if expanded by frictional heat between the convex tip end surface and the casing,
Therefore, when there is a sliding contact surface with the inner wall of the casing, a phenomenon occurs in which the braking force suddenly drops due to the transition from the tip end surface of the convex portion to the grease itself. Since the motor rotates in the reverse direction, the decrease in crime prevention has been a problem.

[0003]

DISCLOSURE OF THE INVENTION The present invention was devised with the object of providing a motor with a reduction mechanism capable of eliminating these drawbacks in view of the above-mentioned circumstances. An end spacer that generates a braking force by being pressed by the thrust force acting on the motor shaft is provided between the end surface of the motor shaft on which the worm that meshes is formed and the inner wall of the resin casing that faces the end surface. In the provided motor with a reduction mechanism, the end spacer is assembled to the inner wall of the casing in a non-rotating manner, and a convex portion for generating a braking force is formed on the contact surface with the end surface of the motor shaft. It is characterized by. Further, the present invention solves the problem that the braking force generated by the end spacer becomes unstable, and improves the crime prevention property of the power window device.

[0004]

Next, an embodiment of the present invention will be described with reference to the drawings. In the drawings, reference numeral 1 denotes a motor with a speed reduction mechanism used for a power window device or the like, and the motor with a speed reduction mechanism 1 integrally includes a motor unit 2 and a speed reduction unit 3.
The motor unit 2 has a bottomed cylindrical motor casing 4 which also serves as a yoke, a permanent magnet 5 fixed to the inner peripheral surface of the motor casing 4, and a motor shaft 6 rotatably supported by the motor casing 4. , A rotor core 7 and a commutator 8 which are integrally assembled to the motor shaft 6, and a brush 9 which slidably contacts the commutator 8, and a worm 6a is integrally formed on the tip side of the motor shaft 6. Has been done.

On the other hand, the speed reducer 3 includes a speed reducer casing 10 formed of resin, a worm wheel 11 meshing with the worm 6a, and an output shaft 13 connected to the worm wheel 11 via a buffer member 12 so as to be rotatable integrally. , The output shaft 13 and the like. The speed reducer 3 outputs the motor power reduced by the worm gear mechanism (the worm 6a and the worm wheel 11) to the window glass opening / closing link mechanism to forcibly open / close the window glass. All are the same as before.

By the way, the motor shaft 6 has a bearing 14 provided at one end of the motor casing 4 and a pair of bearings 1 provided at the motor shaft insertion portion of the reduction casing 10.
The motor casing 6 is rotatably supported by the first and second motor casings 5 and 16.
End spacers 17 for receiving a thrust force acting on the motor shaft 6 are provided on the inner wall of the motor.

The end spacer 17 is made of resin such as polyimide resin so as to integrally include a spacer main body 17a formed in a circular shape and a square column shaped press-fit portion 17b protruding from one end surface of the spacer main body 17a. Is molded. Then, the press-fitting portion 17b is assembled in a rotationally stopped state by press-fitting into the press-fitting recesses 6b and 10a formed in the one end surface of the motor shaft 6 and the inner wall of the speed reduction casing 10. It is carried out between the end spacer 17 provided in 10 and the motor shaft 6. When the worm wheel 11 applies a reversing force and a thrust force to the worm 6a as the window glass is pushed down, the end spacer 17 causes the inner wall of the motor casing 4 or the motor shaft 6 to move on the basis of the thrust force. A braking force (friction force) that opposes the reverse rotation force is generated by pressing against the end face.

Further, a convex portion 17d for determining a braking force (contact area) is formed on the pressing contact surface 17c of the end spacer 17, and the convex portion 17d is formed on the shaft of the motor shaft 6. A plurality of (two in this embodiment) are arranged side by side at predetermined intervals (d) in the circumferential direction while being formed in an arc shape having the center of the arc as the center of the arc. The spacing (d) between the 17d and the shape of the tip surface of each projection 17d are set to be substantially the same. That is, the convex portion 17d
When grease is applied to the pressing contact surface 17c of the end spacer 17 in order to stabilize the wear amount of the end spacer 17, the grease is compressed due to abrasion of the convex portion 17d or expanded by frictional heat. Since it is allowed to flow to the outer peripheral side from the gap between the portions 17d, it is ensured that the braking force is rapidly reduced based on the compression and expansion of the grease as in the case where the grease is sealed in the projection 17d. Can be avoided.

In the embodiment of the present invention constructed as described above, when the window glass is pushed down, this pushing force is input from the output shaft 13a to the speed reduction unit 2 and the worm wheel 11 is pushed.
To the worm wheel 11
When the motor shaft 6 receives a thrust force, the end spacer 17 provided on the inner wall of the reduction casing 10 receives the thrust force from the worm 6a meshing with the motor shaft 6 based on the thrust force. The end spacer 17 pressed against the other end surface of the disk and generates a braking force against the reverse rotation force to prevent the window from being pressed down.

As described above, in the embodiment of the present invention, the end spacer 17 for generating the braking force by receiving the pushing force of the window glass is provided on the inner wall of the reduction casing 10. The end spacer 17 is in sliding contact with the end surface of the motor shaft 6. Therefore, even if heat is generated by the friction of the sliding contact surface, the heat flows to the side of the motor shaft 6 made of metal, the temperature rise is prevented, and the expansion of the grease can be suppressed. Moreover, in this structure, when the convex portions 17d that determine the braking force are formed on the pressing contact surface 17c of the end spacer 17, the plural convex portions 17d are formed at predetermined intervals in the circumferential direction. The grease applied to the pressing contact surface 17c of the end spacer 17 in order to stabilize the amount of wear of the protrusions 17d is compressed by the wear of the provisional protrusions 17d and expanded by frictional heat. It becomes possible to flow out from the gap between them to the outer peripheral side. Therefore, the problem that the braking force sharply decreases due to the compression or expansion of the grease like the one in which the grease is sealed in the convex portion is solved, and as a result, the braking force is stabilized and the power window device is protected against crime. You can improve the property.

Further, as described above, since the change of the braking force due to the compression and expansion of the grease is prevented, it is possible to surely avoid the change of the braking force based on the presence or absence of air contained in the grease. As a result, It is also possible to eliminate the inconvenience that the performance of products varies depending on the grease application state.

Further, in the above embodiment, each of the projections 1
7d are set at the same interval, and each of the projections 17
Since the tip end surface shape of d is set to the same shape, there is no variation in the amount of grease flowing out from each gap and the braking force generated by each convex portion 17d. As a result, stable lubrication and braking performance are obtained. Secure the end spacer 17
Uneven wear and fluctuations in braking force can be prevented.

It should be noted that the present invention is not limited to the above-described embodiment, and for example, the projection 17d of the end spacer may be formed as shown in FIG. That is,
(A) is a projection in which three convex portions 17d each having an arc-shaped distal end face are arranged side by side at predetermined intervals in a circumferential direction, and (B) is a convex portion 17d whose distal end surface is formed in a substantially square shape. (C) shows four protrusions 17d each having a fan-shaped tip surface formed at predetermined intervals in the circumferential direction.
Each of them is arranged side by side, and any one of them can provide the same operation and effect as the first embodiment.

[0014]

In summary, since the present invention is constructed as described above, a braking force is generated between the inner wall of the casing and the motor shaft facing the casing when the motor shaft receives a thrust force. Although the end spacer is provided, the end spacer is provided not on the motor shaft side but on the casing side formed by resin molding, and the end spacer and the motor shaft end surface are in sliding contact with each other in order to apply a braking force. . For this reason, even if heat is generated by friction due to sliding contact, the heat will flow to the motor shaft made of metal, will not be muffled, expansion due to friction heat can be suppressed, and it will always be stable against external force. The generated braking force can be generated to contribute to the improvement of crime prevention in the power window device.

[Brief description of the drawings]

FIG. 1A is a sectional view of a motor with a speed reduction mechanism, and FIG. 1B is an enlarged front view of an end spacer.

FIG. 2 is a sectional view taken along line XX of FIG.

3A is a rear view of the end spacer, and FIG. 3B is a partially cutaway side view of the end spacer.

4A, 4B, and 4C are front views of end spacers showing other examples.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Motor with reduction mechanism 2 Motor part 3 Reduction part 4 Motor part casing 6 Motor shaft 6a Worm 10 Reduction part casing 11 Worm wheel 17 End spacer 17d Convex part

Continuation of front page (51) Int.Cl. ⁶ Identification number Office reference number FI Technical display area E05F 15/10 B60J 1/17 A

Claims (1)

[Claims] 1. A thrust force acting on a motor shaft is pressed between an end face of a motor shaft on which a worm that meshes with a worm wheel is formed and a resin-molded casing inner wall facing the end face. In a motor with a reduction mechanism provided with an end spacer for generating a braking force, the end spacer is assembled on the inner wall of the casing in a non-rotating manner, and for generating a braking force on the contact surface with the end surface of the motor shaft. A motor with a reduction mechanism, characterized in that a convex portion is formed.