JP3101250B2 - Motor with reduction mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention belongs to the technical field of a motor with a speed 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 speed reduction mechanism of this type,
In order to prevent reverse rotation due to external force, a speed reduction mechanism is configured using a worm gear mechanism having a reverse rotation prevention function. However, when this is used as a drive source of a power window device, since it is assumed that an inexploited person strongly pushes down the closed window glass, not only the reverse rotation prevention function of the worm gear mechanism but also the separate worm gear mechanism It has been proposed to provide a reverse rotation prevention mechanism to improve the security. However, the conventional reverse rotation prevention mechanism has a problem that it has a large number of parts and is inferior in assemblability.

Therefore, as disclosed in Japanese Patent Application Laid-Open No. 61-36476, a case (motor yoke or deceleration case) is applied to an end face of a motor shaft integrally formed with a worm by receiving a thrust force acting on the motor shaft. It has been proposed to provide an end spacer that presses and contacts the inner wall and brake the rotation of the motor shaft by the frictional force generated by the end spacer.

In such a motor with a speed reduction mechanism, the yoke for receiving one end of the motor shaft must be formed of a ferromagnetic metal material as in the prior art because it is necessary to form a magnetic path. The deceleration case tends to be formed of a lightweight resin material.In this case, a metal plate is attached to the thrust receiving portion of the deceleration case so that the deceleration case does not wear due to friction with the end spacer, and is attached to the metal plate. The end spacer is pressed and contacted.

[0005]

However, in this case, when frictional heat is generated between the end spacer and the metal plate, the frictional heat has a higher heat conductivity than the resin end spacer. Since it is transmitted to the metal plate side, the metal plate mounting portion of the reduction case may be softened depending on the use conditions. Further, in the above-mentioned conventional motor, a mounting hole for fitting the end spacer into a press-fitting shape and stopping the rotation must be formed at the end of the motor shaft. However, there is a problem that it is difficult to assemble, and it is practically impossible to assemble, and there is a problem to be solved by the present invention.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances and has been made to solve these problems. A yoke in which a motor is incorporated is formed of a ferromagnetic metal material. On the other hand, in a motor with a speed reduction mechanism formed by molding a speed reduction case in which a worm and a worm wheel are incorporated with a resin material, an end surface of a motor shaft integrally formed with the worm and a thrust receiver of the speed reduction case opposed to the end surface. When a resin end spacer that intercepts the thrust force acting on the motor shaft and frictionally brakes the rotation of the motor shaft is interposed between the end spacer and the thrust receiving portion of the reduction case, the end spacer cannot rotate. It is the one that is assembled. By doing so, the frictional heat generated between the end spacer and the motor shaft is almost transmitted to the motor shaft having a high thermal conductivity, and the frictional heat can be transmitted to the reduction case. Thus, it is possible to prevent the deceleration case from being softened, and it is not necessary to form a mounting hole for an end spacer at the end of the motor shaft, so that the present invention can be implemented even with a small-diameter motor shaft. In this structure, the end spacer is non-rotatably supported by a bearing portion incorporated in the yoke so as to rotatably support the motor shaft. It is possible to escape to the motor shaft side via the member, whereby the protection of the end spacer from heat can also be measured.

[0007]

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 reduction mechanism used for a power window device or the like, 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. A motor shaft 4, a rotor core 5, a commutator 6, a brush 7, a permanent magnet 8 and the like are assembled into the yoke 3 of the above. A worm 4a is formed integrally with the outer peripheral surface over a predetermined range.

Reference numeral 9 denotes a speed reducer integrally attached to the motor portion 2. The speed reducer 9 is fitted to a resin-molded speed reducer case 10 for the purpose of weight reduction, and a worm meshed with the worm 4a. Wheel 11, the worm wheel 1
An output shaft 13 integrally rotatably connected to the output shaft 13 via a buffer member 12, an output gear 13a integrally provided on the output shaft 13, and the like are incorporated. And the deceleration unit 9
Outputs the motor power reduced by the worm gear mechanism (the worm 4a and the worm wheel 11) from the output gear 13a to the window glass opening / closing link mechanism (not shown) to forcibly open and close the window glass. The basic configuration is the same as the conventional one.

The base end of the motor shaft 4 is supported by a bearing member 14 provided at the bottom of the yoke 3, while the distal end of the motor shaft 4 inserted into the reduction case 10 is connected to the motor of the reduction case 10. The bearing is supported by a pair of bearing members 15 and 16 provided on the shaft insertion portion 10a, and between the base end surface of the motor shaft 4 and the thrust receiving portion 3a of the yoke 3, and further, the distal end surface of the motor shaft 4 and the reduction case 10 Thrust receiving part 10b
End spacers 17 are interposed between the end spacers 17 to prevent reverse rotation of the motor shaft 4 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 power window deceleration mechanism 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. In order to cope with the thrust force in any direction, end spacers 17 are provided at both end portions of the motor shaft 4.
Is to be interposed.

The end spacer 17 is made of a heat-resistant material such as polyimide resin so as to integrally have a spacer portion 17a formed in a disk shape and a rectangular column-shaped press-fit portion 17b protruding from one end face of the spacer portion 17a. The end spacer 17 interposed on the base end face of the motor shaft 4 on the side opposite to the worm is formed by resin molding using a resin material having excellent wear resistance. By press-fitting into a press-fitting recess 4b formed on the base end surface on the opposite side of the worm, the motor is assembled to the motor shaft 4 in a non-rotatable state. When a reverse rotation force and a thrust force act on the worm 4a from the worm wheel 11 based on the depression of the window glass, the end spacer 17
Receives the thrust force and presses against the thrust receiving portion 3a of the yoke 3 to generate a friction braking force against the reverse rotation force based on the pressing contact. When heat is generated due to friction, the heat is mainly transmitted to the yoke 3 having high thermal conductivity. However, since the yoke 3 is made of metal, there is almost no adverse effect due to frictional heat. become. Reference numeral 17c denotes 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 interposed 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-fit portion 17b is non-rotatably incorporated into the thrust receiving portion 10b of the reduction case 10. Is press-fitted to the deceleration case 10 so as to be non-rotatable. That is, the end spacer 17 on the deceleration case 10 side
When a reverse rotation force and a thrust force are applied to the worm 4a from the worm wheel 11 as the window glass is pressed down, the thrust force is applied to the worm 4a to press and contact the worm-side tip surface of the motor shaft 4; The frictional braking force against the reverse rotation force is generated based on the above, so that the heat generated due to the friction is almost transmitted to the metal motor shaft 4 having a higher thermal conductivity than the resin end spacer 17. As a result, it is possible to avoid the disadvantage that the resin-molded deceleration case 10 is softened by frictional heat. In this embodiment, the metal plate 18 is provided for reinforcement. However, the end spacer 17 can be directly pressed into the recess 10c formed in the thrust receiving portion 10b of the reduction case 10.

In the apparatus constructed as described above, when the window glass is pushed down, this force is transmitted from the output shaft 13 to the speed reduction unit 9.
And acts on the worm wheel 11 as a reverse rotation force, and causes a reverse rotation force and a thrust force to act on the worm 4a meshing with the worm wheel 11. However, when the motor shaft 4 receives the thrust force, the motor shaft 4 Of the end spacers 17 interposed at both ends, the end spacers 17 receive a thrust force to generate a friction braking force against a reversing force, thereby preventing the window glass from being pushed down.

As described above, in the embodiment of the present invention,
End spacers 17 are provided at both ends of the motor shaft 4 to generate a frictional braking force by receiving the pressing force of the window glass. 17 is mounted on the deceleration case 10 side in a non-rotatable state, so that it comes into contact with the worm-side tip surface of the motor shaft 4 to generate friction braking force. Therefore, even if heat is generated due to friction, this heat is almost transmitted to the metallic motor shaft 4 having a higher thermal conductivity than the resin end spacer 17, and the resin is molded. The disadvantage that the deceleration case 10 is softened by frictional heat can be avoided.

Further, unlike the case where the end spacer 17 is mounted on the worm-side end surface of the motor shaft 4, it is not necessary to form a mounting hole at the end of the motor shaft 4. There is an advantage that it can be implemented without any problem even with a difficult small-diameter motor shaft.

Further, the end spacer 17 is connected to the deceleration case 1
Unlike the case where the thrust receiving portion 10b of the deceleration case 10 is provided with a metal plate for preventing abrasion as in the case of pressing and contacting the zero side, the number of parts can be reduced and the assembling operation can be simplified.

It should be noted that the present invention is not limited to the above-described embodiment, but may be applied to a second embodiment shown in FIGS. That is, in this embodiment, the bottomed cylindrical thrust receiving portion 10d formed on the deceleration case 10 side is set to have the same diameter without forming a step like in the first embodiment. The resin-made end spacer 19 is provided with a large-diameter spacer portion 19a.
And a small-diameter insertion portion 19b. 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 receiving body 2 having rubber elasticity.
0 is fitted to the cylinder bottom of the thrust receiving portion 10d in a state of being fitted to the outside. In this mounting state, the elastic receiver 2
0 is repressed, and the end spacer 19
Is 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 denotes a bearing member which is incorporated into the thrust receiving portion 10d in a non-rotating state such as press-fitting so as to rotatably support the distal end portion of the motor shaft 4;
It is set so that the bearing of the motor shaft 4 is provided by the 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, so that the fitting can be performed in a state where the thrust receiving portion 10d is prevented from rotating.

In this case, the braking function receiving the thrust force accompanying the driving of the motor is provided by the motor shaft 4.
Is exerted by rotating in a state where the end of the end spacer 19 is pressed against the spacer portion 19a of the end spacer 19 to be prevented from rotating. However, if the end spacer 19 becomes hot due to frictional resistance at that time, The heat of the end spacer 19 is applied to the bearing member 2 surrounding the spacer portion 19a.
1 to the motor shaft 4
The heat of the end spacer 19 itself can also be positively absorbed by the motor shaft 4 side, so that not only the thrust receiving portion 10d but also the end spacer 19 is protected from the fact that the end spacer 19 becomes hot and accelerates abrasion. be able to. Moreover, in this case, since there is no necessity to drill a mounting hole for mounting the end spacer 19 in the motor shaft 4, even a small-diameter motor shaft 4 can be easily assembled. In addition, in this embodiment, 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 previously incorporated in the bearing member 21, and the thrust receiving portion 10d
The assembly work can be improved as compared with the case where the assembly is performed alone in the small-diameter cylinder.

[0018]

In summary, since the present invention is constructed as described above, the motor shaft is rotated by receiving a thrust force between the thrust receiving portion of the resin-molded deceleration case and the end surface of the motor shaft. However, since the end spacer is non-rotatably assembled to the thrust receiving portion of the reduction case, the end spacer is pressed against the end face of the motor shaft. As a result, a friction braking force is generated. That is, 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, conduction of frictional heat to the deceleration case can be avoided as much as possible, and softening of the deceleration case can be prevented. Further, since it is not necessary to form an assembling hole for the end spacer at the end of the motor shaft, even a small-diameter motor shaft in which it is difficult to form the assembling hole can be implemented without any problem.

[Brief description of the drawings]

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

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

FIG. 3 is an enlarged sectional view of a main 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 a main part showing a second embodiment.

FIG. 6 is a developed 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

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-7-231608 (JP, A) JP-A-61-36476 (JP, A) JP-A 8-275454 (JP, A) 104757 (JP, U) Hikaru 3-48357 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) H02K 7/116

Claims (1)

(57) [Claims] 1. A motor with a reduction mechanism, wherein a yoke in which a motor is incorporated is formed of a ferromagnetic metal material, and a reduction case in which a worm and a worm wheel are incorporated is molded of a resin material, wherein the worm is integrally formed. A resin end spacer that receives a thrust force acting on the motor shaft and frictionally brakes the rotation of the motor shaft is interposed between the end surface of the motor shaft and the thrust receiving portion of the reduction case facing the end surface. In doing so, a motor with a speed reduction mechanism, wherein the end spacer is non-rotatably assembled to a thrust receiving portion of a speed reduction case.