JPH0648361U - Ball bearing holding structure for small motors - Google Patents

Abstract

(57) [Summary] (Correction) [Purpose] To provide a ball bearing holding structure for a small motor that can hold a ball bearing with high precision and can be formed by simple processing only, at a low cost and with high precision. . [Structure] A holding hole 16 in which a bearing radial is formed is formed in a bearing holding portion 2 of a bracket 1, and the holding hole 16 is
The outer peripheral portion 4 of the ball bearing 3 holding the shaft 6 is fitted,
Half-drawing fitting portion 1 half-drawn from the outside of the bracket 1 to the inside of the bracket 1 around the holding hole 16 of the bearing holding portion 2.
7 is formed, a bearing cover 19 is fitted and attached to the half-blanked fitting portion 17, and the shaft insertion hole 20 of the bearing cover 19 is provided in the outer peripheral portion 4 of the ball bearing 3.
The bearing cover 19 is formed smaller and covers the end of the outer peripheral portion 4 of the ball bearing 3 around the shaft insertion hole 20.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a ball bearing holding structure for small motors such as pulse-stepping, brushless, and brush DC servo motors used in office automation equipment such as copying machines and printers.

[0002]

[Prior art]

 Conventionally, the following two methods are generally known as a ball bearing holding structure for a small motor. In these ball bearing holding structures, as shown in FIGS. 6 to 9, the bearing holding portion 2 of the bracket 1 holds the outer peripheral portion 4 of the ball bearing 3, and the inner peripheral portion 5 of the ball bearing 3 holds the shaft. 6 is held, and the thrust direction of the ball bearing 3 to the right in the figure is held by the washer 7.

As shown in FIGS. 6 and 7, the first type ball bearing holding structure is provided with a thrust direction holding portion 8 for holding the thrust direction of the ball bearing 3 to the left in the figure on the bracket 1 side. It is a thing. In the ball bearing holding structure of the first method, the bearing holding portion 2 of the steel plate bracket 1 shown in FIG. 6 is further processed to form the thrust direction holding portion 8, and the thrust direction holding portion 8 shown in FIG. A separate member 9 provided with the holding portion 8 is used to divide the bearing 1 between the bearing holding portion 2 of the bracket 1 and the ball bearing 3.

As shown in FIGS. 8 and 9, the second type of ball bearing holding structure is a flange in which a flange 10 for holding the thrust direction of the ball bearing 3 to the left in the drawing is provided on the ball bearing 3 side. It uses a ball bearing with a ji. In the ball bearing holding structure of the second method, the flange 10 shown in FIG. 8 is further formed on the outer peripheral portion 4 of the ball bearing 3, and the flange 10 as a separate component is attached to the ball bearing 3 shown in FIG. It is divided into

[0005]

[Problems to be solved by the device]

 However, the above two methods have the following problems, respectively. A. Disadvantages of the first method In the case where the steel plate shown in FIG. 6 is processed to form the bearing holding portion 2 of the bracket 1, it is necessary to R-process the base portion B of the reference fitting portion A when mounting the motor. , Expensive. When the separate member 9 shown in FIG. 7 is used, it is expensive because the separate member 9 is manufactured by cutting a non-ferrous alloy. Since it is necessary to process the thrust direction holding portion 8 of the bearing holding portion 2 of the bracket 1 or the separate member 9 by broaching, reamer, and sizing finishing, it takes a lot of work. B. Disadvantage of the second method The ball bearing 3 with a flange is expensive. When the reference fitting portion A at the time of mounting the motor is enlarged, a separate component is required, and the separate component is expensive. When the bearing holding portion 2 of the bracket 1 is processed to have an L-shaped cross section and the reference fitting portion A is enlarged, it is expensive because the root portion B of the reference fitting portion A needs to be rounded. C. Disadvantages common to both methods After the motor is assembled, the thrust backlash adjustment (washer adjustment) of the rotor (not shown in the figure on the right side) cannot be adjusted, and it is necessary to adjust the thrust backlash of the rotor during assembly. Takes.

The present invention has been made in order to solve the above problems, and is an inexpensive and highly accurate small motor that can hold a ball bearing with high accuracy and can be formed by simple processing. It is an object to provide a ball bearing holding structure.

[0007]

[Means for Solving the Problems]

 The ball bearing holding structure for a small motor according to the present invention has a holding hole having a bearing radial formed in the bearing holding portion of the bracket, and the outer peripheral portion of the ball bearing holding the shaft is fitted into the holding hole. Around the holding hole of the bearing holding part, a half-blanked fitting part that is half-blanked from the outside of the bracket to the inside of the bracket is formed, and a bearing cover is fitted and attached to this half-blanked fitting part. The shaft insertion hole of the cover is formed smaller than the outer peripheral portion of the ball bearing, and the bearing cover covers the end of the outer peripheral portion of the ball bearing around the shaft insertion hole.

According to another aspect of the present invention, there is provided a ball bearing holding structure for a small motor, wherein the ball bearing holding structure for the small motor described above has a protruding portion formed around the shaft insertion hole of the bearing cover and protruding toward the inside of the bracket. The tip of the protruding portion is located around the end of the outer peripheral portion of the ball bearing.

Another ball bearing holding structure for a small motor of the present invention is the ball bearing holding structure for a small motor described above, wherein the bearing cover is attached to the bearing holding portion by a screw.

[0010]

【Example】

 A first embodiment in which the ball bearing holding structure for a small motor according to the present invention is applied to a DC servo motor will be described below with reference to FIGS.

As shown in FIG. 1, in the DC servomotor of this embodiment, a magnet 13 is attached inside a magnet yoke 14 arranged around a rotor 11, and input / output is made at both ends of the magnet yoke 14. Side brackets 1 and 1 are mounted and fixed by the motor assembling screw 15, the ball bearings 3 and 3 are held by the bearing holding portions 2 of these brackets 1 and 1, and the rotor 11 and the both sides The shaft 6 is inserted into the spacers 12 and 12 and the ball bearings 3 and 3 on the outside thereof, and the ball bearing 3 holds the shaft 6. A cylindrical bottomed bearing cover 19 that covers the ball bearings 3 with the shaft 6 inserted is attached to the bearing holding portions 2 of the brackets 1 and 1 with screws 23. A pressurizing spring 18 is sandwiched between the bearing cover 19 and the ball bearing 3 on the output side (left side in the figure), and a washer having the same outer diameter as the outer diameter of the ball bearing 3 on the input side (right side in the figure). 21 is sandwiched.

The ball bearing holding structure of this DC servo motor will be described in detail with respect to the output side (left side in FIG. 1) shown in FIGS. 2 and 3, and the bearing holding portion 2 of the brackets 1 and 1 will have a bearing radial (not shown). The holding hole 16 in which the bracket is formed is formed, and a half-drawing fitting portion 17 half-opened from the outside of the bracket 1, 1 to the inside of the bracket 1, 1 is formed around the holding hole 16. An outer peripheral portion 4 of a ball bearing 3 which holds the shaft 6 at an inner peripheral portion 5 is fitted and held in a bearing radial (not shown) in the holding hole 16, and the bearing holding portion 2 has The shaft 6 is inserted into the shaft insertion hole 20 in the center of the bearing cover 19, covers the end of the outer peripheral portion 4 of the ball bearing 3, and fits the outer periphery 22 of the opening into the half-drawing fitting portion 17. It is attached by the screw 23 in this state. The pressure spring 18 sandwiched between the inner surface of the bottom of the bearing cover 19 and the end of the outer peripheral portion 4 of the ball bearing 3 urges the end of the outer peripheral portion 4 of the ball bearing 3 in the thrust direction. There is.

The ball bearing 3 is held in the radial direction by a bearing radial (not shown) in the holding hole 16 of the bearing holding portion 2, and the pressurizing spring 18 (see FIGS. 1 and 2) or the washer 21 (see FIG. The thrust direction is maintained by the bearing cover 19 via the bearing cover 19. As shown in FIGS. 1 and 2, the bearing cover 19 has a shaft insertion hole 20 smaller than the outer peripheral surface of the outer peripheral portion 4 of the ball bearing 3, and protrudes inwardly of the bracket 1 and 1 around the shaft insertion hole 20. As shown in FIG. 3, four protruding portions 24 are formed at equal intervals, and at the output side, the tips of these protruding portions 24 abut on the outer circumference of the pressurizing spring 18 so that the pressurizing spring 18 is attached to the ball bearing 3. It is precisely positioned at the end of the outer peripheral portion 4 and holds the pressing spring 18 in the radial direction.

In the ball bearing holding structure having such a structure, the bearing holding portions 2 of the brackets 1 and 1 can be formed only by drawing and pressing, and the bearing cover 19 can be formed by complete drawing / pressing parts. Is. The bearing radial of the holding hole 16 of the bearing holding portion 2 can be accurately machined only by press working, but broaching, reamer, and sizing can be easily carried out if necessary. In this ball bearing holding structure, the reference fitting portion A at the time of motor assembly is not the bearing holding portion 2 of the brackets 1 and 1, but the opening outer periphery 22 is fitted to the half-draw fitting portion 17 of the bearing holding portion 2. Since the outer circumference of the cylindrical portion of the combined bearing cover 19 is provided, it is not necessary to machine the root portion B of the reference fitting portion A.

When assembling the DC servomotor to which the ball bearing holding structure of the present invention is applied, first, between the inner surface of the bottom of the bearing cover 19 on the output side and the end of the outer peripheral portion 4 of the ball bearing 3. The pressurizing spring 18 is clamped, the washer 21 is clamped between the inner surface of the bottom of the bearing cover 19 on the input side and the end of the outer peripheral portion 4 of the ball bearing 3, and the outer periphery 22 of the opening of each bearing cover 19 is clamped. The bearing cover 19 is attached to the bearing holding portion 2 with the screw 23 while fitted in the half-pulled fitting portion 17 of the bearing holding portion 2 of the brackets 1 and 1 on the input / output side. The shaft 6 is inserted into the spacer 12 and the ball bearing 3 outside thereof, and the shaft 6 is held in the ball bearing 3. After doing this, the magnet 13 and the magnet yoke 14 are arranged around the rotor 11, and both ends of the shaft 6 are inserted into the shaft insertion holes 20 of the bearing cover 19 attached to the bearing holder 2 of the brackets 1 and 1. Insert the outer peripheral portion 4 of the ball bearing 3 into the bearing radial (not shown) of the holding hole 16 of the bearing holding portion 2, mount the brackets 1 and 1 on both ends of the magnet yoke 14, and mount the motor assembly screw. Fix with 15.

After assembling the DC servomotor in this way, after removing the screw 23 of the input side bearing cover 19 and removing the bearing cover 19, and adjusting the thrust play of the rotor 11 by replacing the washer 21 and the like. , The bearing cover 19 is screwed again.

Next, a second embodiment of the ball bearing holding structure for a small motor according to the present invention will be described with reference to FIGS. 4 and 5.

As shown in FIGS. 4 and 5, the ball bearing holding structure of this embodiment has substantially the same structure as the ball bearing holding structure of the first embodiment. However, in the ball bearing holding structure of this embodiment, A flange portion 25 is formed on the outer peripheral portion of the bearing cover 19. The flange portion 25 is fitted into the half-drawing fitting portion 17, and the bearing cover 19 is welded to the bracket 25 by welding (welding portion 26) of the flange portion 25. It is attached to one and one bearing holder 2.

[0019]

[Effect of device]

 According to the ball bearing holding structure for a small motor of the present invention, a holding hole having a bearing radial is formed in the bearing holding portion of the bracket, and the outer peripheral portion of the ball bearing holding the shaft is fitted into this holding hole. A half-blanked fitting part is formed around the holding hole of the bearing holding part by half-blanking from the outside of the bracket to the inside of the bracket, and the bearing cover is fitted and attached to this half-blanked fitting part, and Since the shaft insertion hole of this bearing cover is formed smaller than the outer peripheral portion of the ball bearing, and the bearing cover covers the end of the outer peripheral portion of the ball bearing around the shaft insertion hole, the bottom portion of the bearing cover is covered. A pressure spring or washer is sandwiched between the inner surface and the outer edge of the ball bearing, and the thrust direction of the ball bearing is maintained by the bearing cover via the pressure spring or washer. As a result, the ball bearing can be held with high accuracy, and the bearing holding part of the bracket and the bearing cover can be formed only by drawing and pressing. It can be kept low, which makes it possible to obtain an inexpensive and highly accurate ball bearing holding structure. Therefore, according to the ball bearing holding structure for a small motor of the present invention, a high-performance small motor can be provided at low cost. Further, by making the shape of the bearing cover into a cylindrical shape with a bottom, the outer circumference of the cylindrical portion can be used as a reference fitting portion when mounting the motor.

Further, according to another embodiment of the ball bearing holding structure for a small motor of the present invention, a protrusion that protrudes inside the bracket is formed around the shaft insertion hole of the bearing cover, and the tip of the protrusion is a ball bearing. Since it is located around the end of the outer peripheral part of the bearing, the tip of the protruding part abuts on the outer periphery of the pressurizing spring sandwiched between the inner surface of the bottom of the bearing cover and the end of the outer peripheral part of the ball bearing. Thus, the pressurizing spring can be accurately positioned at the end portion of the outer peripheral portion of the ball bearing, and the radial direction of the pressurizing spring can be maintained.

Furthermore, in the ball bearing holding structure of another small motor according to the present invention, the bearing cover is attached to the bearing holding portion with a screw, so that only the bearing cover is removed without disassembling the motor body after the motor is assembled. The rotor can be adjusted by adjusting the rotor, and it is not necessary to adjust the thrust backlash of the rotor at the time of assembly. As a result, the assembly is easy and the motor assembly labor cost can be kept low.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a DC servo motor showing a first embodiment in which a ball bearing holding structure for a small motor of the present invention is applied to a DC servo motor.

FIG. 2 is an enlarged cross-sectional view of the ball bearing holding structure in FIG.

FIG. 3 is a sectional view taken along line XX in FIG.

FIG. 4 is an enlarged cross-sectional view of a ball bearing holding structure according to a second embodiment of the ball bearing holding structure for a small motor of the present invention.

5 is a sectional view taken along line XX in FIG.

FIG. 6 is a cross-sectional view showing a conventional ball bearing holding structure for a small motor.

FIG. 7 is a cross-sectional view showing another conventional ball bearing holding structure for a small motor.

FIG. 8 is a cross-sectional view showing another conventional ball bearing holding structure for a small motor.

FIG. 9 is a cross-sectional view showing another conventional ball bearing holding structure for a small motor.

[Explanation of symbols]

 1 Bracket 2 Bearing holding part 3 Ball bearing 4 Outer peripheral part 6 Shaft 16 Holding hole 17 Half-drawing fitting part 19 Bearing cover 20 Shaft insertion hole 23 Screw 24 Protruding part A Reference fitting part B Root part

Claims (3)

[Scope of utility model registration request] 1. A holding hole in which a bearing radial is formed is formed in a bearing holding portion of a bracket, and an outer peripheral portion of a ball bearing holding a shaft is fitted into the holding hole, and a holding hole of the bearing holding portion is formed. A half-blanked fitting part that is half-blanked from the outside of the bracket to the inside of the bracket is formed around it. A ball bearing holding structure for a small motor, which is formed smaller than an outer peripheral portion, and a bearing cover covers an end portion of the outer peripheral portion of the ball bearing around a shaft insertion hole thereof. 2. The ball bearing holding structure for a small motor according to claim 1, wherein a protruding portion that protrudes toward the inside of the bracket is formed around the shaft insertion hole of the bearing cover, and the tip of the protruding portion is the outer peripheral portion of the ball bearing. A ball bearing holding structure for a small motor, characterized in that it is located around the end of the. 3. The ball bearing holding structure for a small motor according to claim 1, wherein the bearing cover is attached to the bearing holding portion with a screw.