JPH0640454Y2 - Assembly structure of motor with worm reduction mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] The present invention relates to an assembly structure of a motor with a worm speed reduction mechanism used for electrical components for automobiles and the like.

[Problems to be Solved by Prior Art and Invention] In general, some motors of this type are provided with a worm gear at the tip of a motor shaft and engage the worm gear with a worm wheel to reduce the motor output. is there. By the way, such a worm reduction mechanism needs to have a configuration in which the worm gear meshes at the tangential position of the worm wheel, while on the motor side, the motor shaft is extended to the tangential position so as not to interfere with the worm wheel. Worm gear needs to be provided. The protrusion length of the motor shaft becomes longer and unstable as the diameter of the worm wheel becomes larger, resulting in greater blurring. Therefore, in order to eliminate this blurring, the shaft diameter of the motor shaft has conventionally been made thicker, but this has a problem that the motor becomes unnecessarily large, which violates the recent demand for smaller and lighter motors.

As a measure against the vibration of the motor shaft, it is proposed to support the motor shaft at an intermediate portion on the motor yoke side of the worm gear portion, and in that case, the bearing is fitted and supported by the casing. However, in this case, when the motor shaft is installed in the casing, it is necessary to install it so that the worm gear part passes through the bearing.If this is done, the worm gear part must be made smaller in diameter than the bearing inner diameter, and it is necessary to make it a large diameter. There is a problem that there is a limit. In contrast,
The bearing is preliminarily embedded in the motor shaft of small diameter,
It is proposed to press-fit the built-in bearing into the casing side when the worm gear part is installed in the casing, but in this case, the bearing must be press-fitted in the casing with the worm gear part installed. There is a problem that the workability of the built-in work is poor.

Therefore, in order to reduce the weight of the motor shaft, in order to reduce the diameter of the motor shaft, there is no choice but to support the motor shaft through a bearing (ball metal) on the motor frame side where the brush holder is provided. In the case of not only the bearing position is still far from the worm gear mounting position, but the motor shaft is inserted into the bearing that is press-fitted and assembled into the motor frame to which the brush holder is attached, and the motor is assembled.
Since the worm gear is press-fitted and attached to the tip of the motor shaft protruding from the motor frame, when the worm gear is press-fitted and attached, the motor frame may be deformed due to an unreasonable force. It cannot be adopted immediately.

[Means for Solving the Problems] The present invention has been made in view of the above circumstances, and was devised with the object of providing an assembly structure of a motor with a worm reduction mechanism that can eliminate these drawbacks. The large-diameter worm gear that is integrally attached to the motor shaft tip that protrudes from the opening edge of the motor yoke meshes with the worm wheel that is installed inside the casing that is integrally attached to the opening edge of the motor yoke. On the other hand, in the motor with a worm speed reduction mechanism, the motor frame provided with a brush holder for a brush slidably contacting the commutator is integrally interposed between the opening edge portion of the motor yoke and the casing. On the motor shaft, the bearing is freely rotatable at the casing side position and at the intermediate position between the motor yoke opening edge and the worm gear mounting part. On the other hand, the motor frame is formed with a through hole that can pass through the worm gear and the bearing, and the outer peripheral surface of the bearing is held so as to restrict movement of the bearing through the through hole in the axial direction. A plurality of projecting pieces having a holding portion formed at the tip and having elasticity in the radial direction are integrally projected toward the worm gear side, and further, the outer peripheral surface of the bearing holding portion is provided with a support hole formed in the casing. It is fitted so as to contact the inner peripheral surface, and the bearing is supported by the casing via the bearing holding portion,
Furthermore, the contact surface between the bearing holder and the support hole of the casing is made non-circular, and a rotation restricting means for restricting rotation of the bearing holder around the axis is formed.

According to this configuration, the present invention can provide a worm gear with a large diameter attached to the tip of the motor shaft with a small diameter.
It is possible to suppress the deviation of the motor shaft to be small and to easily mount the motor.

[Embodiment] Next, an embodiment of the present invention will be described with reference to the drawings. In the drawings, 1 is a motor with a worm reduction mechanism,
The armature unit 2 of the motor 1 is housed in a motor yoke 3 having a cylindrical shape with a bottom. One end of the motor shaft 4 is rotatably supported by the bottom of the motor yoke 3, while the other end of the motor shaft 4 projects from the opening edge of the motor yoke 3. A worm gear 5 having a diameter larger than that of the motor shaft 4 is integrally attached to the protruding tip portion. Further, a ball metal 6 is provided at an intermediate position between the opening edge portion of the motor yoke 3 of the motor shaft 4 and the attachment portion of the worm gear 5. (Corresponding to the bearing of the present invention) is freely rotatably inserted.

A motor frame 7 is provided with a brush holder 9a for a brush 9 which is in sliding contact with the commutator 2a of the armature unit 2. The motor frame 7 is provided between an opening edge of the motor yoke 3 and a casing 12 described later. The motor frame 7 has a through hole 7a through which the worm gear 5 and the ball metal 6 of the motor shaft 4 can be penetrated.
Are formed. Further, a ball metal holding portion 10a for externally embracing the outer peripheral surface of the ball metal 6 is formed on the tip of the motor frame 7 so as to restrict movement of the ball metal 6 penetrating the through hole 7a in the axial direction. A plurality of protruding pieces 10 having elasticity in the radial direction are integrally formed so as to protrude toward the worm gear 5 side. Here, the outer diameter of the worm gear 5, the ball metal 6, the commutator 2a, and the inner diameter of the through hole 7a are such that the outer diameter of the worm gear 5 ≦ the outer diameter of the ball metal 6 <the inner diameter of the through hole 7a and the outer diameter of the commutator 2a. Is set to. Then, in order to assemble the motor frame 7 to the motor yoke 3, the ball metal 6
With the worm gear 5 being press-fitted and attached to the tip end of the motor shaft 4 through which the motor is inserted, the motor frame 7 is penetrated from the side where the brush holder 9a is provided and brought into contact with the opening edge of the motor yoke 3. Is being made,
In this state, the ball metal 6 is the ball metal holding portion.
It is adapted to be externally fitted and held in a state in which movement in the axial direction is restricted by 10a. In addition, 11 is a washer.

On the other hand, 12 is a worm wheel that meshes with the worm gear 5.
Reference numeral 13 is a casing in which the casing 12 is integrally assembled with a bolt 8 while the motor frame 7 is interposed on the opening edge side of the motor yoke 3. The hole formed in the casing 12 for the insertion of the ball 4 is formed as a support hole 14 for supporting the ball metal 6. That is, when the motor shaft 4 to which the ball metal 6, the worm gear 5, and the motor frame 7 are attached is lightly press-fitted into the support hole 14 of the casing 12, the outer peripheral surface of the ball metal holding portion 10a is inside the support hole 14. It comes into surface contact with the peripheral surface and is fitted and fixed in a state of being restricted in rotation about the axis. That is, a flat surface portion 14a is formed on the inner peripheral surface of the support hole 14 to form a non-circular shape, while the outer peripheral surface of the ball metal holding portion 10a has a flat surface portion 14a.
The chamfer 10b is formed to correspond to. Then, by aligning the chamfered portion 10b with the flat surface portion 14a and lightly press-fitting the ball metal support portion 10a into the support hole 14 as described above, the rotation of the ball metal support portion 10a around the axis is restricted. In this state, the ball metal 6 is fitted into the support hole 14, so that the ball metal 6 is supported by the casing 12 via the ball metal support portion 10a. Reference numeral 15 is a thrust plate provided on the casing 12 to receive the thrust load at the tip of the motor shaft 4.

In the embodiment of the present invention constructed as described above, assembling of the motor 1 is as follows. First, as described above, the worm gear 5 having a large diameter is press-fitted and attached to the motor shaft 4 into which the ball metal 6 is inserted. The motor frame 7 is assembled by penetrating it from the side where the brush holder 9a is provided, and is further assembled in the casing 12 in which the worm wheel 13 is installed.

As described above, according to the present invention, the motor shaft 4 can be made small in diameter by attaching the large diameter worm gear 5 to the tip portion thereof, which contributes to the weight reduction and size reduction of the motor. , Is supported by the bow metal 6 supported by the casing 12 through the bearing holding portion 10a at the tip of the elastic protruding piece 10 protruding from the motor frame 7 toward the worm gear 5, and the bearing position is the motor frame 7 position. It is closer to the worm gear 5, and as a result, even when the motor shaft 4 has a small diameter and projects from the motor yoke 3 for a long time, it is possible to suppress the blurring during motor rotation as much as possible. Therefore, when a worm wheel having a large diameter is used to obtain a large reduction ratio without requiring a large output like a motor used for a motor antenna device of an automobile, the motor shaft diameter is adjusted to the required performance. You can make it thin,
This can greatly contribute to the reduction in size and weight of the motor.

Moreover, since the large-diameter worm gear 5 is configured to penetrate the through hole 7a of the motor frame 7, the worm gear 5 can be press-fitted and attached to the tip of the motor shaft 4, and then the motor frame 7 can be assembled. There is no problem that the motor frame 7 is deformed due to an unreasonable force acting on the motor frame 7 when the 5 is press-fitted. Moreover, the armature balance can be corrected with the worm gear 5 attached. , Accurate balance correction can be done.

Further, at the same time as the motor yoke 3 is assembled to the casing 12, the ball metal holding portion 10a is fitted and fixed in the support hole 14,
As a result, the ball metal 6 is held in the ball metal holding portion 10a.
Since it is supported by the casing 12 via the, the work of separately mounting a metal holder for ball metal on the side of the casing 12 is not required, and the mounting work can be simplified.

In addition, the ball metal holding portion 10a supported in the support hole 14 of the casing 12 in a lightly press-fitted state is in a state in which the rotation is restricted around the axis by the flat surface portion 14a and the chamfer 10b that are in contact with each other in a non-circular state. Ball metal holder 10 for mating
Even if a is projected in the axial direction and is easy to rotate around the axis as it is, the ball metal holding portion 10a is
Since the ball metal 6 can be held in a fixed state in which the rotation around the axis is restricted, the ball metal holding portion 10
It is possible to surely prevent co-rotation of a with the motor shaft 4, and to stably support the ball metal 6, as well as the ball metal holding portion.
It is possible to avoid early damage of 10a. Moreover, since the ball metal holding portion 10a can be lightly press-fitted in the state of being positioned with respect to the support hole 14, it can greatly contribute to the improvement of workability of the assembling work.

[Effects] In summary, since the present invention is configured as described above, the motor shaft can be made small in diameter by integrally mounting a large diameter worm gear on the tip side, which contributes to weight reduction and size reduction. However, the motor shaft is supported by the bearing supported by the casing via the bearing holding portion at the tip of the protruding piece having elasticity protruding from the motor frame toward the worm gear side, and the bearing thereof is also supported. The position is closer to the worm gear than the position of the motor frame, and as a result, a bearing with a small diameter motor shaft is adopted, and the bearing is mounted on the motor frame side instead of on the casing. It is located near the worm gear inside and can be supported by the bearing casing via the bearing holding part, so that there is no blur and a stable model. Data axis.

Moreover, since the large-diameter worm gear is configured to pass through the through hole of the motor frame, the motor frame is pressed outward at the tip of the motor shaft through which the bearing is inserted, and the motor frame is moved outward from the brush holder side. Therefore, there is no need to press-fit the motor shaft after installing the worm gear as in the conventional bearing that press-fits the motor frame to support the small-diameter motor shaft. In the previous process of assembling the armature, it is possible to press-fit the worm gear into the motor shaft, and it is possible to surely avoid applying an unreasonable force to the motor frame, and it is possible to greatly improve reliability.

Moreover, the contact surface between the supporting hole of the casing and the bearing holding portion is formed in a non-circular shape, and the bearing holding portion is fitted into the supporting hole in a state in which the rotation is restricted around the axis, so that the bearing Even if the holding portion projects in the axial direction and is easy to rotate around the axis as it is, co-rotation of the bearing holding portion with the motor shaft can be reliably prevented. As a result, the bearing holding portion can hold the bearing in a fixed state in which the rotation around the shaft center is restricted, so that the bearing can be stably supported and the bearing holding portion can be prevented from being prematurely damaged by co-rotation. Can be avoided. Moreover, since the bearing holding portion can be lightly press-fitted while being positioned in the support hole, it is possible to greatly contribute to improvement in workability when assembling the motor frame to the casing.

[Brief description of drawings]

The drawings show an embodiment of an assembly structure of a motor with a worm speed reducer according to the present invention, wherein FIG. 1 is a side view of the motor with a main portion cross-sectioned, and FIGS. 2A and 2B are motor frames. A cross-sectional view, a bottom view, and FIG. 3 are motor frame mounting surfaces of the casing. 2a is a commutator, 3 is a motor yoke, 4 is a motor shaft,
5 is a worm gear, 6 is a ball metal, 7 is a motor frame, 7a is a through hole, 9 is a brush, 9a is a brush holder, 10 is a protruding piece, 10a is a ball metal holding portion, 10b is a chamfer, 12 is a casing, 13 is a The worm wheel, 14 is a support hole, and 14a is a flat surface portion.

Claims (1)

[Scope of utility model registration request] 1. A large-diameter worm gear integrally attached to a motor shaft tip end portion protruding from an opening edge portion of a motor yoke,
A motor frame provided with a brush holder for a brush that is in sliding contact with a commutator while being meshed with a worm wheel that is internally mounted in a casing that is integrally attached to the opening edge of the motor yoke is provided with the casing of the motor yoke. In a motor with a worm speed reduction mechanism that is integrally interposed between the motor shaft and the motor shaft, the bearing is free at the casing side position and at the intermediate position between the motor yoke opening edge and the worm gear mounting part. While the motor frame is rotatably inserted, a through hole that can penetrate the worm gear and the bearing is formed in the motor frame, and the outer peripheral surface of the bearing is fitted to the outer peripheral surface of the bearing so as to restrict movement of the bearing penetrating the through hole in the axial direction. A plurality of projecting pieces, each of which has a bearing holding portion for holding the end portion and which has elasticity in the radial direction, are integrally projected toward the worm gear side. Further outer peripheral surface of the bearing holder,
The bearing is supported by the casing through the bearing holding portion by being fitted so as to come into contact with the inner peripheral surface of the supporting hole formed in the casing, and the contact surface between the bearing holding portion and the supporting hole of the casing is made non-circular. A mounting structure of a motor with a worm speed reduction mechanism, characterized in that a rotation restricting means for restricting rotation of the bearing holding portion around an axis is formed.