JPH08322196A - Geared motor - Google Patents

Abstract

PURPOSE: To prevent a resin reduction gear case from being softened with frictional heat generated from an end spacer by building the end spacer fixedly in the trust bearing part of the reduction gear case. CONSTITUTION: An end spacer 17 is built in fixedly on the reduction gear case 10 side at the forward end face part on the worm side of a motor shaft 4 by press fitting a press fitting part in a square hole of a metal plate 18 being build fixedly in the thrust bearing part 10b of a reduction gear case 10. When a window glass is pushed down and reverse rotating force and thrust force acts on a worm 4a from a worm wheel 11, the end spacer 17 on the reduction gear case 10 side generates frictional brake force resisting against the reverse rotating force and the heat generated through friction is transmitted to the side of metal motor shaft 4 having thermal conductivity higher than that of the resin end spacer 17. This structure can avoid softening of the resin molded reduction gear case 10 due to frictional heat.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technical field of a motor with a reduction mechanism used for electric components such as a power window device of an automobile.

[0002]

2. Description of the Related Art Generally, in a motor with a reduction mechanism of this type,
In order to prevent the reverse rotation due to the external force, the speed reduction mechanism is configured by using the worm gear mechanism having the reverse rotation prevention function. However, when using this as a drive source for a power window device, it is assumed that an inexperienced person will strongly push down the closed window glass, so not only the reverse rotation prevention function of the worm gear mechanism but also a separate worm gear mechanism It has been proposed to provide a reverse rotation prevention mechanism to improve the crime prevention performance, but the conventional reverse rotation prevention mechanism has a problem that the number of parts is large and the assembling property is poor.

Therefore, as disclosed in Japanese Patent Laid-Open No. 61-36476, a case (motor yoke or deceleration case) receives a thrust force acting on the motor shaft on the end surface of the motor shaft integrally formed with a worm. ) It is proposed that an end spacer that is pressed against the inner wall is provided, and the rotation of the motor shaft is braked by the frictional force generated by the end spacer.

By the way, in such a motor with a reduction mechanism, the yoke that receives one end of the motor shaft is formed of a ferromagnetic metal material as in the past because it is necessary to form a magnetic path, but a worm gear mechanism is incorporated. The deceleration case tends to be molded with a lightweight resin material.In this case, attach a metal plate to the thrust receiving part of the deceleration case so that the deceleration case does not wear due to friction with the end spacers. The end spacers are pressed against each other.

[0005]

However, in this case, when frictional heat is generated between the end spacer and the metal plate, the frictional heat has a higher thermal conductivity than that of the resin-made end spacer. Since it is transmitted to the metal plate side, the metal plate attachment part of the reduction gear case may be softened depending on the usage conditions. Furthermore, in the above-mentioned conventional type, it is necessary to form a mounting hole at the tip of the motor shaft for fitting the end spacer in a press-fitting manner to prevent rotation, so this mounting hole is formed for a motor shaft with a small tip diameter. There is a problem in that it is difficult to install and practically cannot be assembled, and there are problems to be solved by the present invention.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances to solve these problems, and a yoke in which a motor is incorporated is formed of a ferromagnetic metal material. On the other hand, in a motor with a reduction mechanism formed by molding a worm and a reduction case incorporating a worm wheel with a resin material, an end face of a motor shaft integrally formed with the worm and a thrust receiving member of the reduction case facing the end face. When a resin-made end spacer that frictionally brakes the rotation of the motor shaft by receiving a thrust force acting on the motor shaft is interposed between the end spacer and the bearing part, the end spacer cannot be rotated in the thrust receiving part of the deceleration case. It is assembled into. By doing so, the frictional heat generated between the end spacers and the motor shaft is almost transmitted to the motor shaft side having high thermal conductivity, and the frictional heat can be transmitted to the deceleration case. It is possible to prevent the deceleration case from softening, and it is also possible to implement the invention with a motor shaft having a small diameter without the need to make a mounting hole for an end spacer at the tip of the motor shaft. Further, in this structure, the end spacer is non-rotatably supported by the bearing portion incorporated in the yoke so as to rotatably support the motor shaft. It can be released to the motor shaft side via the member, and thereby the end spacer can be protected from heat.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the drawings. In the drawings, reference numeral 1 denotes a motor with a reduction mechanism used in a power window device, etc., and a motor portion 2 of the motor 1 with a reduction mechanism has a bottomed cylindrical shape formed of a ferromagnetic metal material to form a magnetic path. The motor shaft 4, the rotor core 5, the commutator 6, the brush 7, the permanent magnet 8 and the like are incorporated in the yoke 3 of the above. The tip side of the motor shaft 4 projects from the yoke 3 and A worm 4a is integrally formed on the outer peripheral surface portion over a predetermined range.

Reference numeral 9 denotes a reduction gear unit which is integrally assembled with the motor unit 2. The reduction gear unit 9 is a worm geared to the worm 4a in a reduction gear case 10 made of resin for the purpose of weight reduction. Wheel 11, the worm wheel 1
1, an output shaft 13 integrally rotatably connected through a buffer member 12, an output gear 13a integrally provided on the output shaft 13, and the like are incorporated. And the speed reducer 9
Outputs the motor power decelerated in the worm gear mechanism (worm 4a and worm wheel 11) to the window glass opening / closing link mechanism (not shown) from the output gear 13a to forcibly open and close the window glass. All basic configurations are conventional.

The base end side of the motor shaft 4 is supported by a bearing member 14 provided at the bottom of the yoke 3, while the tip end side of the motor shaft 4 inserted into the speed reduction case 10 is a motor of the speed reduction case 10. The bearing is supported by a pair of bearing members 15 and 16 provided on the shaft insertion portion 10 a, but is between the base end surface of the motor shaft 4 and the thrust receiving portion 3 a of the yoke 3, and further between the tip end surface of the motor shaft 4 and the reduction gear case 10. Thrust receiving part 10b
An end spacer 17 is interposed between and to prevent the motor shaft 4 from rotating in the reverse direction by receiving the thrust force of the motor shaft 4 generated when the window glass is pushed down. That is,
In a general automobile, since the same motor 1 with a reduction mechanism for power windows is incorporated in the left and right doors in a left-right inverted manner, the direction of the thrust force generated when the window glass is pushed down is also inverted. The end spacers 17 are provided on both end surfaces of the motor shaft 4 in order to cope with the thrust force in either direction.
To intervene.

The end spacer 17 is integrally formed with a disk-shaped spacer portion 17a and a square column-shaped press-fitting portion 17b protruding from one end surface of the spacer portion 17a. The end spacer 17 is resin-molded by using a resin material having excellent wear resistance. The end spacer 17 provided on the base end face of the motor shaft 4 on the side opposite to the worm side has the press-fitting portion 17b and the motor shaft 4 By being press-fitted into the press-fitting concave portion 4b formed on the base end surface on the side opposite to the worm side, the motor shaft 4 is assembled in a non-rotatable state. Then, when a reverse force and a thrust force are applied from the worm wheel 11 to the worm 4a based on the pushing down of the window glass, the end spacer 17
Receives the thrust force and presses against the thrust receiving portion 3a of the yoke 3, and based on this press contact, a friction braking force that resists the reverse rotation force is generated. Further, when heat is generated due to friction, the heat is mainly transferred to the yoke 3 side having high thermal conductivity, but since the yoke 3 is made of metal, the adverse effect of frictional heat hardly occurs. become. Reference numeral 17c is an annular convex portion formed on the pressing contact surface of the end spacer 17, and the braking force is determined based on the tip area of the convex portion 17c.

On the other hand, the end spacer 17 provided on the worm-side end surface portion of the motor shaft 4 has a square hole 18a of a metal plate 18 in which the press-fitting portion 17b is non-rotatably incorporated into the thrust receiving portion 10b of the reduction gear case 10. By press-fitting into, the deceleration case 10 is assembled in a non-rotatable state. That is, the end spacer 17 on the deceleration case 10 side
When the reverse rotation force and the thrust force are applied from the worm wheel 11 to the worm 4a as the window glass is pushed down, the thrust force is applied to the worm-side tip surface of the motor shaft 4, and the press contact is performed. Since the frictional braking force against the reverse rotation force is generated on the basis of this, the heat generated by the friction is almost transmitted to the metal motor shaft 4 side having a higher thermal conductivity than the resin end spacer 17. As a result, the disadvantage that the resin-molded deceleration case 10 is softened by friction heat can be avoided. Although the metal plate 18 is provided for reinforcement in the present embodiment, the end spacer 17 can be directly press-fitted into the recess 10c formed in the thrust receiving portion 10b of the speed reduction case 10.

In the structure as described above, when the window glass is pushed down, this force is applied from the output shaft 13 to the speed reducer 9
Is input to the worm wheel 11 as a reverse rotation force, and the worm 4a meshing with the worm wheel 11 is subjected to a reverse rotation force and a thrust force. However, when the motor shaft 4 receives the thrust force, One of the end spacers 17 installed at both ends of the shaft receives a thrust force to generate a frictional braking force against the reverse rotation force, thereby preventing the window glass from being pushed down.

As described above, according to the embodiment of the present invention,
The end spacers 17 that generate a frictional braking force by receiving the pressing force of the window glass are provided at both ends of the motor shaft 4, and the end spacers that are provided at the worm-side end surface of the motor shaft 4 are provided. Since 17 is attached to the deceleration case 10 side in a non-rotatable state, it is pressed against the worm-side tip surface of the motor shaft 4 to generate a friction braking force. Therefore, even if heat is generated due to friction, this heat is almost transmitted to the metallic motor shaft 4 side, which has a higher thermal conductivity than the resin-made end spacers 17, and is resin-molded. It is possible to avoid the disadvantage that the deceleration case 10 is softened by frictional heat.

Further, unlike the case where the end spacer 17 is assembled to the worm-side tip surface of the motor shaft 4, it is not necessary to form an assembly hole at the tip of the motor shaft 4, so that the assembly hole is not formed. There is an advantage that even a motor shaft having a small diameter can be implemented without problems.

Further, the end spacer 17 is attached to the deceleration case 1
Since it is not necessary to provide a metal plate for wear prevention on the thrust receiving portion 10b of the deceleration case 10 as in the case of pressing against the 0 side, it is possible to reduce the number of parts and simplify the assembling work.

The present invention is of course not limited to the above-mentioned embodiment, but can also be applied to the second embodiment shown in FIGS. 5 and 6. That is, in this structure, the bottomed cylindrical thrust receiving portion 10d formed on the speed reduction case 10 side is set to have the same diameter without forming a step like the first embodiment. The resin-made end spacer 19 has a large-diameter spacer portion 19a.
The R-shaped tip of the motor shaft 4 abuts on the surface of the spacer portion 19a, and the insertion portion 19b has an elastic receiver 2 having rubber elasticity.
0 is fitted to the bottom of the cylinder of the thrust receiving portion 10d in an externally fitted state. In this mounted state, the elastic receiving body 2
0 is being suppressed and the end spacer 19
Is set to be pressed in the direction of the motor shaft 4.
On the other hand, a chamfered portion 19c is formed on the outer periphery of the spacer portion 19a. Reference numeral 21 is a bearing member that is incorporated in the thrust receiving portion 10d in a rotation-stopped state such as press-fitting in order to rotatably support the tip end portion of the motor shaft 4. The bearing member 21 is
The bearing of the motor shaft 4 is set to be formed by the one-half portion 21a on the yoke 2 side. And the other half 21 of the bearing member 21
A chamfered portion 21c corresponding to the chamfered portion 19c is formed on the inner peripheral surface of b, and fitting and assembling can be performed in a state where the thrust receiving portion 10d is prevented from rotating.

In this structure, the braking function by receiving the thrust force caused by the driving of the motor is the motor shaft 4
It is exhibited by rotating in a state of pressing the spacer portion 19a of the end spacer 19 whose front end is prevented from rotating, but if the end spacer 19 becomes high heat due to frictional resistance at that time, The heat of the end spacer 19 causes the bearing member 2 surrounding the spacer portion 19a.
It will be transmitted to the motor shaft 4 via 1
The heat of the end spacers 19 themselves can be positively absorbed by the motor shaft 4 side, so that not only the thrust receiving portion 10d but also protection from the fact that the end spacers 19 become highly heated and wear is promoted is also measured. be able to. Moreover, in this structure, since it is not necessary to form a mounting hole for mounting the end spacer 19 in the motor shaft 4, even a motor shaft 4 having a small diameter can be assembled without any problem. Moreover, in this structure, the attachment of the end spacer 19 to the thrust receiving portion 10d is performed by the end spacer 19
Can be attached as an assembly member that is incorporated in the bearing member 21 in advance, and the thrust receiving portion 10d can be attached.
It is possible to improve the assembling work as compared with the case of assembling independently in the small diameter cylinder.

[0018]

In summary, since the present invention is constructed as described above, the rotation of the motor shaft is affected by the thrust force between the thrust receiving portion of the resin-molded reduction case and the end surface of the motor shaft. The resin-made end spacer that frictionally brakes the end spacer is mounted non-rotatably on the thrust receiving part of the speed reduction case, so the end spacer is pressed against the end face of the motor shaft. Frictional braking force is generated. In other words, even if friction heat is generated between the end spacer and the motor shaft,
This heat is almost transmitted to the motor shaft side having a high thermal conductivity, and as a result, it is possible to prevent the friction heat from being transferred to the deceleration case as much as possible and prevent the deceleration case from softening. Further, since it is not necessary to form an assembling hole for the end spacer at the tip of the motor shaft, it is possible to carry out even a small-diameter motor shaft where it is difficult to form the assembling hole without any problem.

[Brief description of drawings]

FIG. 1 is a sectional view of a motor with a reduction mechanism.

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

FIG. 3 is an enlarged sectional view of an essential part showing an assembled state of an end spacer.

4A is a front view of an end spacer, FIG. 4B is a rear view, and FIG. 4C is a partially cutaway side view.

FIG. 5 is an enlarged sectional view of an essential part showing a second embodiment.

FIG. 6 is a development view showing a second embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Motor with reduction mechanism 2 Motor part 3 Yoke 3a Thrust receiving part 4 Motor shaft 4a Worm 9 Reduction part 10 Reduction case 10b Thrust receiving part 11 Worm wheel 17 End spacer 19 End spacer 19c Chamfering part 21 Bearing member 21c Chamfering part

Claims (2)

[Claims] 1. In a motor with a reduction mechanism, wherein a yoke in which a motor is incorporated is formed of a ferromagnetic metal material, and a deceleration case in which a worm and a worm wheel are incorporated is formed of a resin material, wherein the worm is integrally formed. An end spacer made of resin for interposing a thrust force acting on the motor shaft to frictionally brake the rotation of the motor shaft is interposed between the end face of the motor shaft and the thrust receiving portion of the deceleration case facing the end face. In doing so, a motor with a speed reduction mechanism configured such that the end spacer is non-rotatably assembled to the thrust receiving portion of the speed reduction case. 2. The motor with a reduction mechanism according to claim 1, wherein the end spacer is non-rotatably supported by a bearing portion incorporated in a reduction case to rotatably support a motor shaft.