JPH08172747A - Thrust pad structure and electric motor with speed reducer - Google Patents

Abstract

PURPOSE: To provide an electric motor with speed reducer for achieving a stable performance over a long period using a thrust pad made of synthetic resin which can be easily manufactured by the compression formation method of polyimide resin and has excellent mechanical strength and wear-resistance performance. CONSTITUTION: In an electric motor with speed reducer, an output shaft 9 is provided at a rotor shaft 1 rotating in both forward and backward directions via a worm gear 5 and a helical gear 6 and the tip surface of the rotor shaft 1 is pressed to the tip contact surface of a thrust pad 7 made of resin which has a larger outer diameter than the rotor shaft 1 and has ring-shaped protruding parts at the surrounding.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thrust receiving structure provided at the tip of a rotary shaft of an electric motor or the like, and a motor with a speed reducer using this thrust receiving structure. It is used for motors for opening and closing automobile windows.

[0002]

2. Description of the Related Art Conventionally, as an electric motor with a speed reducer used as an electric motor for opening and closing a window of an automobile, for example, Japanese Patent Publication No. 3-34.
No. 554 is disclosed. The electric motor with a reducer encloses a worm tooth formed on the rotor shaft of the motor and a helical gear that meshes with the worm tooth with a housing, and encloses the anti-worm tooth side of the rotor shaft with a motor case, The thrust force acting on the rotor shaft presses the resin thrust receiver fixed to the worm tooth side tip and the rotor shaft opposite to the worm tooth side tip to generate a braking force by pressing it against the inner surface of the housing and the motor case. The tip end contact surface of the resin thrust receiver is formed in a ring shape. By configuring the electric motor with a speed reducer as described above, the thrust force by the rotor shaft of the electric motor makes contact with the tip contact surface of the resin thrust receiver and the inner surface of the housing and the motor case that contact the tip contact surface of the resin thrust. A frictional force is generated between it and the mating material such as the metal plate provided on the inner surface of the
This acts as a braking force against the window falling, and thereby a window falling prevention mechanism is obtained. Further, as the resin thrust receiver, by forming the tip contact surface in contact with the mating member in a ring shape, the effective radius of the ring does not change even if the tip contact surface is worn, so that a stable braking force is maintained for a long period of time. In addition, the braking force can be freely set by setting the ring radius arbitrarily, and further, the recess in the center of the ring can be used as a grease reservoir for reducing sliding wear and sliding noise. The effect is that you can do it.

In the above publication, the resin thrust is
It is described that a polyimide resin is used. In the case of manufacturing the resin thrust receiver as described above using this polyimide resin, in order to realize the abrasion resistance and the stability of the friction coefficient required for the resin thrust receiver, and further to achieve sufficient heat resistance against friction heat. Among the polyimide resins, it is necessary to use the wholly aromatic polyimide resin having the highest heat resistance. A preferable example thereof is one having a chemical structure as shown in formula (1).

[0004]

Embedded image

It is well known that these wholly aromatic polyimide resins are generally molded into a predetermined shape by compression molding of resin powder.

[0006]

However, due to the thrust force acting on the rotor shaft of the electric motor as described above,
Resin thrust receiver at the tip of the rotor shaft When the friction force generated between the tip contact surface of the rotor shaft and the mating material is used as the braking force, the resin thrust receiver is ring-shaped at the tip contact surface using this wholly aromatic polyimide resin. When, and the density of the ring-shaped convex portion obtained by compression molding is low, there is a problem in strength, cracks and the like easily occur at the time of mold release, and the polyimide resin There is a possibility that the wear resistance originally possessed may be significantly reduced. That is, the figure
As shown in FIG. 12, when the green body G is formed by compressing and molding the polyimide resin resin powder in the mold M, the concave portion y in the green body G, which is the surface of the supporting portion having the ring-shaped tip contact surface protruding therefrom, is While being strongly compressed by the convex portion y ′ on the molding surface of the mold M, the green that becomes the ring-shaped tip contact surface of the resin thrust receiver molded corresponding to the concave portion x ′ on the molding surface of the mold M. Molding pressure is less likely to be applied to the convex portion x of the body G, and the density of the convex portion x becomes relatively low. When the tip contact surface is formed in a ring shape as described above, the mechanical strength of the tip contact surface is increased. As a result, the abrasion resistance and the like are deteriorated. Therefore, in order to improve the density of the ring-shaped tip contact surface, it is necessary to increase the molding pressure at the time of molding, but this is not preferable because the mold M is overloaded.

Therefore, according to the present invention, the thrust receiver made of synthetic resin used in the above-described electric motor with reduction gear, etc. can be easily manufactured by the compression molding method of polyimide resin and the like, and the mechanical strength and resistance can be improved. It is intended to provide a thrust receiving structure and a motor with a reducer, which are excellent in wear performance and can exhibit stable performance over a long period of time.

[0008]

The present inventors have completed the present invention as a result of intensive studies in view of such problems.
That is, the gist of the present invention is to solve the problems at the time of compression molding such as the polyimide resin by forming the tip contact surface of the resin-made thrust receiver used in the thrust receiving structure to be flat, and to improve the mechanical strength. A thrust receiving structure with excellent abrasion resistance has been realized.

That is, the thrust receiving structure according to the present invention is
A ring shape around a flat tip contact surface having an outer diameter larger than that of the rotating shaft, on the inner surface of the motor case or the inner surface of the housing facing the distal end surface of the rotating shaft of the electric motor, or on the metal plate attached to the inner surface. A structure in which a resin-made thrust receiver around which the convex portion is provided is fixed, and the tip end surface of the rotary shaft is pressed against the tip contact surface surrounded by the ring-shaped convex portion in the resin-made thrust receiver, an electric motor, etc. At the tip of the rotary shaft, a resin thrust receiver having a ring-shaped convex portion around the flat tip contact surface is fixed, and the motor case inner surface or the housing inner surface facing the tip surface of the rotary shaft, Alternatively, a convex shaft having an outer diameter smaller than the outer diameter of the tip contact surface of the resin thrust receiver is provided on a metal plate attached to the inner surface of the resin thrust receiver. A structure in which the tip contact surface surrounded by the ring-shaped convex portion of the thrust bearing made of metal is pressed, the inner surface of the motor case or the inner surface of the housing facing the tip surface of the rotating shaft of an electric motor, or metal attached to those inner surfaces. A resin thrust receiver having a flat tip contact surface is fixed to the plate, and a concave portion having an inner diameter smaller than the outer diameter of the tip contact surface of the resin thrust receiver is formed in the tip surface of the rotating shaft. The structure in which the tip end surface of the rotary shaft having the recess is pressed against the tip contact surface of the resin thrust receiver, and the tip contact surface of the tip end of the rotary shaft of an electric motor or the like is made flat. A metal plate attached to the inner surface of the motor case or the inner surface of the housing, which is fixed to the formed resin thrust receiver and faces the tip end surface of the rotating shaft. An inner surface of the motor case in which a recess having a smaller inner diameter than the outer diameter of the tip contact surface of the resin thrust receiver is bored, and the tip contact surface of the resin thrust receiver fixed to the tip of the rotary shaft is formed with the recess. Alternatively, the structure is such that it is pressed against the inner surface of the housing or the metal plate attached to the inner surface.

The above resin thrust receiver is preferably made of polyimide resin.

The motor with reduction gear according to the present invention is
In a motor with a reducer in which an output shaft is provided through a reducer on a rotor shaft that rotates in both forward and reverse directions, and a thrust load acts on both ends of the rotor shaft, thrust bearings at both ends of the rotor shaft are provided. As the structure, the thrust receiving structure as described above is adopted.

[0012]

According to the resin thrust receiving structure of the present invention as described above, the thrust force acting on the rotary shaft of the electric motor or the like causes the resin thrust receiver to face the front end surface of the rotary shaft of the electric motor. When provided on the inner surface of the housing or the like, the resin thrust receiver is fixed between the tip surface of the rotary shaft and the tip contact surface of the resin-made thrust receiver that comes into contact therewith, and at the tip of the rotary shaft. In this case, a frictional force is generated between the tip contact surface of the resin thrust receiver and the inner surface of the motor case or the like that comes into contact with the tip contact surface, and a braking force for the rotating shaft is generated. Therefore, in the electric motor with a speed reducer in which the resin thrust receiver is attached to the tip of the rotor shaft, the inner surface of the motor case facing the tip surface of the rotor shaft or the inner surface of the housing of the speed reducer, the tip contact surface of the resin thrust receiver is The frictional force generated at the portion becomes a braking force, and when used as an automobile window opening / closing motor, it can be used as a window falling prevention mechanism.

As described above, since the tip end contact surface of the resin thrust receiver used in the thrust receiving structure of the present invention is formed flat, when it is formed by compression molding of polyimide resin or the like, Since the molding surface of the tip contact surface is molded with sufficient molding pressure from the mold, the tip contact surface has a sufficient mechanical strength that is required as a thrust receiver. It has abrasion resistance and stable quality, and can exhibit stable performance as a thrust receiver for a long period of time. Incidentally, in the case where a ring-shaped convex portion is provided around the tip contact surface of the resin thrust receiver, molding pressure is relatively hard to act on the ring-shaped convex portion during compression molding, and the density is Although it has low mechanical strength and relatively low abrasion resistance, no thrust force acts on this part, so there is no problem at all.

Further, in the case where the tip contact surface of the resin thrust receiver is surrounded by a ring-shaped convex portion, the inside surrounded by the ring-shaped convex portion also flattens the entire tip surface of the resin thrust receiver. In the case where a concave portion is formed on the inner surface of the motor case or housing or the metal plate attached to the inner surface of the motor case or the housing on which the tip contact surface is pressed, the concave portion is for reducing sliding wear and sliding noise. Can be used as a grease reservoir.

[0015]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

FIG. 1 shows an embodiment of an electric motor with a speed reducer using a resin thrust receiver according to the present invention, and is a simplified view with a part cut away. In the figure, reference numeral 1 is a rotor shaft,
Reference numeral 10 is a rotor, 11 is a magnet, 3 is a brush, 5 is a worm tooth formed on the rotor shaft 1, and a helical gear 6 is provided in mesh with the worm tooth 5 to form a speed reducer. Therefore, the output shaft 9 is attached to the helical gear 6 via a buffer member or the like (not shown). Further, metal plates 8 are attached to the inner surfaces of the housing 4 of the reduction gear and the motor case 2 so as to face both ends of the rotor shaft 1 on the worm teeth 5 side and the rotor 10 side, respectively. , 8, resin thrust receivers 7, 7 are fixed to the two resin thrust receivers 7, 8.
Both of the front end surfaces of the rotor shaft 1 are pressed against the front end contact surface of the rotor 7.

The resin thrust receiver 7 is made of a polyimide resin. For example, as shown in FIGS. 2 and 3, one surface of a flat cylindrical support portion 71 is formed flat to form a tip contact surface. 72, a ring-shaped convex portion 74 is provided around the tip contact surface 72 so as to surround the tip contact surface 72, and a support shaft 73 having a rectangular cross section is provided on the other surface of the support portion 71 so as to project therefrom. The support shaft 73 is non-rotatably fixed by being press-fitted into the perforation 12 formed in the surface 8a of the metal plate 8 attached to the inner surface of the motor case 2 and the inner surface of the housing 4 of the electric motor, and is fixed to the tip contact surface 72. The rotor shaft 1 is attached with the front end surface 1a thereof being pressed.

In the electric motor with reduction gear according to the present invention as described above, due to the thrust force acting on the rotor shaft 1,
The frictional force generated between the tip surface 1a of the rotor shaft 1 and the tip contact surface 72 of the resin thrust receiver 7 fixed to the metal plate 8 on the inner surface of the motor case 2 and the housing 4, which is pressed against the rotor shaft 1, brakes. When used as an electric power for opening and closing an automobile window, it can be used as a window falling prevention mechanism. At this time, the resin thrust receiver 7
Since the inside of the ring-shaped convex portion 74 projecting around the tip contact surface 72 can be used as a grease reservoir, sliding wear and sliding noise can be reduced.

When the ring-shaped convex portion 74 is formed on the tip end surface of the resin thrust receiver 7 by compression molding of polyimide resin or the like as described above, the convex portion 74 is less likely to receive molding pressure. Although the density is relatively low and wear resistance and mechanical strength are inferior, in the thrust receiving structure according to the present invention, since no load is applied to the protrusions 74, the wear resistance of the ring-shaped protrusions 74 is low. It does not matter at all if the mechanical strength is a little low. On the other hand, the tip contact surface 72 formed flat is subjected to a large molding pressure evenly during compression molding, so that a high-density and uniform molding surface can be obtained, and the abrasion resistance required for the thrust receiver is obtained. It is possible to obtain a resin-made thrust receiver 7 having a stable quality and satisfying the requirements for mechanical properties and mechanical strength. Further, as shown in FIG. 4, if the inner peripheral surface 74a of the ring-shaped convex portion 74 protruding around the tip contact surface 72 of the resin thrust receiver 7 is formed in a tapered shape or a curved shape as shown in FIG. It does not cause cracks or chips when releasing the mold due to the draft of the mold.

In the above embodiment, the resin thrust receiver 7 is used.
Is fixed to the metal plate 8 facing the rotor shaft 1 so as to press the front end surface 1a of the rotor shaft 1. As shown in FIGS. 5 and 6, this resin thrust receiver 7 is mounted on the rotor shaft 1. It can also be fixed to one side. That is, the support shaft 73 of the resin thrust bearing 7 is press-fitted and fixed to the hole 13 provided in the tip surface 1a of the rotor shaft 1, and the surface 8a of the metal plate 8 facing the tip of the rotor shaft 1 is fixed. The protruding shaft 14 having an outer diameter smaller than the outer diameter of the tip contact surface 72 of the resin thrust bearing 7, that is, the inner diameter of the ring-shaped convex portion 74 provided around the tip contact surface 72 is provided in advance. The tip contact surface 72 of the resin-made thrust receiver 7 at the tip of the rotor shaft 1 is attached to the tip surface 14a of the rotor while pressing it. Further, as shown in the figure, on one tip side of the rotor shaft 1, for example, the tip on the worm tooth 5 side (hereinafter referred to as "worm tooth tip 1A"), the metal thrust receiver 7 is attached to the metal plate 8A. The rotor shaft 1 is attached so that the tip surface 1a of the rotor shaft 1 is pressed against its tip contact surface 72, and the rotor shaft 1 is attached to the other rotor 10 side tip (hereinafter referred to as "rotor side tip 1B"). The resin thrust receiver 7 is fixedly attached to the surface of the metal plate 8.
It may be pressed against the tip surface 14a of the protruding shaft 14 provided on the 8a. In the above example, the resin thrust receiver 7 is fixed to the surface 8a of the metal plate 8 provided on the inner surface of the motor case 2 or the housing 4 by forming the perforations 12 therein, but the metal plate 8 is omitted. Then, the inner surface of the motor case 2 or the housing 4 may be directly perforated to fix the resin-made thrust receiver 7 there. Alternatively, the resin-made thrust receiver 7 may be fixed to the rotor shaft 1 side. Also in this case, the protruding shaft 14 may be provided on the inner surface of the motor case 2 or the housing 4 and the resin thrust receiver 7 may be pressed against this.

Next, FIGS. 7 and 8 show another thrust receiving structure according to the present invention. In this thrust receiving structure, the resin thrust receiver 7 made of a polyimide resin is used similarly to the above, but here, the ring-shaped projection 74 as described above is provided around the tip contact surface 72. Instead, the entire one surface of the flat cylindrical support portion 71 is formed as a flat circular tip contact surface 72. On the other surface of the support portion 71, a support shaft 73 having a rectangular cross section is projectingly provided similarly to the resin thrust receiver 7 of the above-mentioned embodiment, and the support shaft 73 is bored on the surface 8a of the metal plate 8. It is non-rotatably fixed by being press-fitted into the hole 12, and the rotor shaft 1 of the electric motor is attached to the tip contact surface 72.
It is attached with the front end surface 1a thereof pressed. Further, in the case of this thrust receiving structure, the rotor shaft 1 against which the tip contact surface 72 of the resin thrust receiving 7 is pressed
Is formed with a recess 15 having an inner diameter smaller than the outer diameter of the tip contact surface 72 of the resin thrust receiver 7, and the tip surface of the rotor shaft 1 is closed. 1a is pressed against the tip surface 1a of the resin thrust receiver 7.

Also in the case of this thrust receiving structure, similarly to the above, due to the thrust force acting on the rotor shaft 1, the tip contact surface 72 of the resin thrust receiver 7 and the tip of the rotor shaft 1 pressed against it. The frictional force generated between the surface 1a serves as a braking force and serves as a window falling prevention mechanism when used as an automobile window opening / closing motor.

In the resin thrust receiver 7 used here, the entire one surface of the supporting portion 71 is formed flat to form the tip contact surface 72. Therefore, the tip contact surface 72 has a large molding pressure during compression molding. Can evenly form a high-density and uniform molding surface, and the density is low, such as when forming the tip contact surface in a ring shape, and cracks and cracks may occur during mold release. In addition, the resin thrust receiver 7 of stable quality that satisfies the wear resistance and mechanical strength required as the thrust receiver can be obtained, and a stable braking force is generated for a long period of time.
Further, since the inside of the recess 15 formed in the surface 8a of the metal plate 8 can be used as a grease reservoir, sliding wear and sliding noise can be reduced.

Also in the case of this thrust receiving structure, the resin thrust receiving 7 is not fixed to the metal plate 8 side provided on the inner surface of the motor case 2 or the housing 4, but as shown in FIGS. 9 and 10. In addition, the resin thrust receiver 7 can be fixed to the rotor shaft 1 side. In this case, the recess 16 is provided in the surface 8a of the metal plate 8 against which the resin thrust receiver 7 is pressed, so that the inside can be used as a grease reservoir. Further, as shown in FIG. 9, at the worm-teeth-side end 1A of the rotor shaft 1, the resin thrust receiver 7 is provided on the surface 8a of the metal plate 8A.
And the rotor shaft 1 having the concave portion 15 formed in the tip surface 1a is pressed against the tip contact surface 72 of the resin thrust receiver 7, and at the rotor side tip 1B, the rotor shaft 1 has a resin The thrust receiver 7 is fixed and the surface
It may be attached so that the tip contact surface 72 of the resin thrust receiver 7 is pressed against the metal plate 8B having the recess 16 formed in 8a. Also in this case, the metal plate 8 may be omitted and the resin thrust receiver 7 may be fixed directly to the inner surface of the motor case 2 or the housing 4, or the resin thrust receiver 7 fixed to the rotor shaft 1 side. The tip contact surface 72 of the thrust receiver 7 may be directly pressed against the inner surface of the motor case 2 or the housing 4.

Further, various thrust receiving structures according to the present invention as described above, that is, the resin thrust receiving 7 (hereinafter referred to as "the resin-made thrust receiving portion 7" in which the ring-shaped convex portion 74 is provided around the flat tip contact surface 72). Convex thrust resin-made thrust receiver 7A)), and a resin-made thrust receiver 7 (hereinafter, referred to as "flat-shaped resin-made thrust receiver 7") having a flat tip contact surface 72 on one entire surface of the support portion 71.
B ". ) Can be used in combination as thrust receiving structures at both ends of the rotor shaft 1, and further, those resin thrust receivers 7 are fixed to the rotor shaft 1, or the surface 8a of the metal plate 8 Alternatively, it may be provided directly on the inner surface of the motor case 2 or the housing 4. FIG. 11 shows some examples of various combinations of such thrust receiving structures at both ends of the rotor shaft 1. That is, as shown in FIG. 11 (a), the surface of the metal plate 8A in which the flat resin thrust receiver 7B is fixed to the worm tooth side tip 1A of the rotor shaft 1 and the tip contact surface 72 is provided with the recess 15 is formed. It is mounted in a state of being pressed against 8a, and at the rotor side tip 1B, the convex resin thrust receiver 7A is fixed to the surface 8a of the metal plate 8B and the tip surface 1a of the rotor shaft 1 is pressed against the tip contact surface 72 thereof. 11 (b), the convex resin thrust receiver 7A is fixed to the worm tooth side tip 1A of the rotor shaft 1, and the tip contact surface 72 of the metal plate 8A is fixed. The rotor shaft tip 1B is mounted while being pressed against the tip surface 14a of the protruding shaft 14 protruding from the surface 8a, while the flat resin thrust receiver 7B is fixed to the metal plate 8B at the tip end contact surface 72 of the rotor plate. Tip surface 1a of rotor shaft 1 And attached to the pressing state, also in FIG. 10 (c), the
On the worm tooth side tip 1A side of the rotor shaft 1, a convex resin thrust receiver 7A is fixed to the metal plate 8A, and the tip contact surface 72 of the rotor shaft 1 is pressed against the tip surface 1a of the rotor shaft 1. A convex resin thrust receiver 7A is fixed to the side tip 1B so that the tip contact surface 72 is the surface of the metal plate 8B.
8a, which is pressed against the tip surface 14a of the protruding shaft 14 protruding from 8a, and FIG. 10 (d) shows the worm tooth end 1A of the rotor shaft 1.
At the tip of the, the flat resin thrust receiver 7B is fixed to the metal plate 8A, and the tip surface 1a having the recessed portion 16 of the rotor shaft 1 is pressed against the tip contact surface 72.
Flat resin thrust receiver 7 fixed to rotor side tip 1B
A metal plate 8B having a concave portion 15 at the tip contact surface 72 of B
It is attached while being pressed against the surface 8a of the. In addition to this, the convex resin thrust receiver 7A, the flat resin thrust receiver 7B, and these are fixed to the rotor shaft 1,
Alternatively, the combination fixed to the metal plate 8 or the inner surface of the motor case 2 or the housing 4 can be arbitrarily selected.
Needless to say, the resin thrust receivers 7 of the same type can be similarly fixed to both ends of the rotor shaft 1.

The support shaft 73 projecting from the other surface of the support portion 71 of the resin thrust bearing 7 as described above is not limited to the rectangular cross section as in the above embodiment. , Pentagonal section, hexagonal section, etc., press-fitted into a hole formed in the tip surface 1a of the rotor shaft 1, the surface of the metal plate 8 or the inner surface of the motor case 2 or the housing 4,
Any shape can be used as long as the resin thrust receiver 7 can be fixed in a non-rotatable manner.
Can be provided. Further, this fixing support shaft does not necessarily have to be provided in the resin thrust receiver 7, and the support portion 71 of the resin thrust receiver 7 is perforated.
The tip surface 1a of the rotor shaft 1 or the surface 8a of the metal plate 8,
Alternatively, it is possible to press-fit and fix the support shaft projecting on the inner surface of the motor case 2 or the housing 4 into the hole provided in the support portion 71 of the resin thrust receiver 7.

Further, the shape of the support portion 71 of the resin thrust receiver 7 does not necessarily have to be circular in cross section.
Particularly, in the case where the resin thrust receiver 7 is directly fixed to the surface of the metal plate 8 or the inner surface of the motor case 2 or the housing 4, the tip contact surface 72 is the rotor shaft 1.
As long as it can contact the tip surface 1a of the
It may be formed in a rectangular cross section or in any other shape.

The thrust receiver 7 made of synthetic resin used in the present invention as described above is mainly made of a polyimide resin, but has the same abrasion resistance and heat resistance as the polyimide resin. If it exists, it may be made of a synthetic resin such as a fluororesin, and may be, for example, a resin composition in which a polyimide resin and a fluororesin are mixed.

For example, polytetrafluoroethylene, tetrafluoroethylene / hexafluoropropylene copolymer, tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer, polychlorotrifluoroethylene, polyfluoride are added to such aromatic polyimide resin powder. Fluorine resin such as vinylidene fluoride, polyvinyl fluoride, ethylene / tetrafluoroethylene copolymer, ethylene / chlorotrifluoroethylene copolymer, polyfluoroalkyl acrylic polymer, polyfluoroalkyl vinyl polymer, polyfluoroalkoxy polymer It can also be added. The addition amount of the fluororesin is appropriately selected, but is preferably 0.1 to 20% by weight with respect to the polyimide resin.

Further, in addition to the above-mentioned fluororesin,
By adding a filler as needed, the mechanical characteristics, sliding characteristics, and the like of the molded resin thrust receiver can be improved. Specific examples of the filler include graphite, molybdenum disulfide, boron nitride, polytetrafluoroethylene, silicone rubber, silicone resin, glass fiber, carbon fiber, aramid fiber, potassium titanate fiber, aluminum, lead and various metals. Examples thereof include oxides. Further, these fillers may be blended alone. The blending amount of these fillers is appropriately selected, but is preferably 0.1 to 50% by weight with respect to the polyimide resin.

[0031]

According to the resin thrust bearing structure of the present invention as described above, when the resin thrust bearing is fixed to the tip of the rotary shaft by the thrust force acting on the rotary shaft of the electric motor or the like. Is provided between the tip contact surface of the resin thrust receiver and the inner surface of the motor case or the like pressed against it, and the resin thrust receiver is provided on the inner surface of the motor case or housing facing the tip surface of the rotating shaft of the electric motor. In this case, a frictional force is generated between the tip surface of the rotating shaft and the tip contact surface of the resin thrust receiver against which it is pressed,
Braking force is generated on the rotating shaft. Therefore, in the electric motor with a speed reducer in which this resin thrust receiver is attached to the tip of the rotor shaft or the inner surface of the motor case facing the tip surface of the rotor shaft or the inner surface of the housing of the speed reducer, the tip contact of the resin thrust receiver The frictional force generated on the surface portion becomes a braking force, and when used as an automobile window opening / closing motor, it can be used as a window falling prevention mechanism.

Further, in the present invention, since the resin thrust receiver used in the thrust receiving structure has a flat tip contact surface, when the tip contact surface is formed by compression molding of polyimide resin or the like, the tip end surface is made flat. A sufficient molding pressure from the mold acts on the molding surface of the contact surface to mold it uniformly and with high density, and it has sufficient mechanical strength and abrasion resistance required as a thrust receiver. It is possible to provide a resin thrust receiver that has stable quality and can exhibit stable performance as a thrust receiver for a long period of time. or,
In the case where a ring-shaped convex portion is provided around the tip contact surface of the resin thrust receiver, the molding pressure during compression molding acts on the ring-shaped convex portion as compared with the tip contact surface. Although it is difficult and the molding density is relatively low and the mechanical strength and wear resistance are lower than those of the tip contact surface, no thrust force acts on this part, so there is no problem at all.

Further, in the case where the tip contact surface of the resin thrust receiver is surrounded by a ring-shaped convex portion, the inside surrounded by the ring-shaped convex portion also flattens the entire tip surface of the resin thrust receiver. The metal plate attached to the inner surface of the motor case or the housing or the inner surface of the motor case or the housing on which the tip contact surface is pressed, or the recess formed on the rotor shaft is used as a grease reservoir. It is possible to reduce sliding wear and sliding noise.

[Brief description of drawings]

FIG. 1 is a partially cutaway simplified front view showing an embodiment of an electric motor with a reduction gear.

FIG. 2 is a vertical sectional view of a thrust bearing structure of a rotor shaft end portion.

FIG. 3 is an exploded perspective view of the thrust receiving structure.

FIG. 4 is an enlarged view of a ring-shaped convex portion of a resin thrust receiver.

FIG. 5 is a vertical sectional view of a thrust receiving structure at both ends of a rotor shaft.

FIG. 6 is an exploded perspective view of a thrust receiving structure.

FIG. 7 is a vertical sectional view of a rotor shaft end portion showing another example of the thrust receiving structure.

FIG. 8 is an exploded perspective view of the thrust receiving structure.

FIG. 9 is a longitudinal sectional view of both ends of a rotor shaft showing another example of the thrust receiving structure.

FIG. 10 is an exploded perspective view of the thrust receiving structure.

11A to 11D are longitudinal sectional views of both ends of a rotor shaft showing various examples of thrust receiving structures.

FIG. 12 is a simplified explanatory diagram of a synthetic resin compression molding method.

[Explanation of symbols]

1 rotor shaft, 2 motor case, 3 brushes, 4
Housing, 5 worm teeth, 6 helical gears,
7 Resin thrust receiver, 8 Metal plate, 9
Output shaft, 10 rotors, 11 magnets, 12 perforations, 13 perforations, 14 salient shafts, 15 recesses, 16 recesses, 71 support parts,
72 Tip contact surface, 73 support shaft, 74 ring-shaped protrusion.

Claims (7)

[Claims] 1. A flat tip contact surface having an outer diameter larger than that of the rotating shaft on an inner surface of a motor case or an inner surface of a housing facing the end surface of a rotating shaft of an electric motor or the like, or a metal plate attached to the inner surface. A resin-made thrust receiver around which a ring-shaped protrusion is provided is fixed, and the tip end surface of the rotary shaft is pressed against the tip-contact surface surrounded by the ring-shaped protrusion in the resin thrust receiver. Thrust receiving structure characterized by 2. A resin thrust receiver in which a ring-shaped convex portion is provided around a flat tip contact surface is fixed to the tip of a rotary shaft of an electric motor or the like and faces the tip of the rotary shaft. A convex shaft having an outer diameter smaller than the outer diameter of the tip contact surface of the resin thrust receiver is provided on the inner surface of the motor case or the inner surface of the housing, or a metal plate attached to the inner surface, and the resin is attached to the tip surface of the convex shaft. A thrust receiving structure, characterized in that a tip contact surface surrounded by a ring-shaped convex portion of a thrust receiving plate is pressed. 3. A resin thrust receiver having a flat tip contact surface is fixed to an inner surface of a motor case or an inner surface of a housing facing the tip surface of a rotating shaft of an electric motor or the like, or to a metal plate attached to the inner surface. A recess having a smaller inner diameter than the outer diameter of the tip contact surface of the resin thrust receiver is formed in the tip surface of the rotary shaft, and the tip surface of the rotary shaft having the recess is formed in the resin thrust. A thrust receiving structure characterized by being pressed against the tip contact surface of the receiving portion. 4. A resin thrust receiver having a flat tip contact surface is fixed to the tip of a rotary shaft of an electric motor or the like, and an inner surface of a motor case or an inner surface of a housing facing the tip surface of the rotary shaft, or A metal plate attached to the inner surface of the resin thrust receiver is provided with a recess having an inner diameter smaller than the outer diameter of the tip contact surface of the resin thrust receiver. A thrust receiving structure, wherein the thrust receiving structure is adapted to be pressed against an inner surface of a motor case having the recess formed therein, an inner surface of a housing, or a metal plate attached to the inner surface. 5. The thrust receiving structure according to claim 1, wherein the resin thrust receiving is made of polyimide resin. 6. A motor with a speed reducer in which an output shaft is provided on a rotor shaft rotating in both forward and reverse directions via a speed reducer, and a thrust load acts on both ends of the rotor shaft. The thrust receiving structure at both ends is defined as claim 1.
An electric motor with a speed reducer, which employs the thrust receiving structure according to claim 4. 7. The electric motor with a reducer according to claim 6, wherein the resin thrust receiver is made of polyimide resin.