JPH069355U - motor - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a motor in which the fixed position of the bearing is prevented from being displaced, the verticality of the shaft is improved, and the influence of noise is prevented. [Structure] A pair of metallic bearings 2, 3 rotatably supporting a shaft 1 is held by an insulating holder 4, and a yoke plate 5 is projected on an inner peripheral surface of a through hole 4A of the insulating holder 4. The bottom surface 2B of the bearing 2 is brought into contact with the end surface 5D of the yoke plate 5. The yoke plate 5 may be grounded.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a motor used as a rotation drive source for various electronic devices.

[0002]

[Prior art]

 For example, the structure of FIG. 7 is known as a brushed motor applied to a VTR, a tape recorder, or the like. Reference numeral 1 denotes a shaft, which is rotatably supported by a pair of metallic bearings 2 and 3, and these bearings 2 and 3 are held by an insulating holder 4. The insulating holder 4 is made of synthetic resin integrally molded with the yoke plate 5. Reference numeral 6 is a rotor portion including a core 8 and a coil 7 fixed to the shaft.

8 and 9 are a plan view and a cross-sectional view showing a bearing holder assembly 10 used in the motor of FIG. 7. In this bearing holder assembly 10, a yoke plate 5 and an insulating holder 4 are integrally formed. It consists of: The motor uses such a bearing holder assembly 10 to press-fit a pair of bearings 2 and 3 into the through hole 4A in the insulating holder 4 and then insert the shaft 1 into the bearings 2 and 3. Can be assembled. Next, a method of press-fitting and fixing the pair of bearings 2 and 3 will be described with reference to FIGS. 10 to 12.

First, as shown in FIG. 10, tools such as a guide bar 16, a die 17, and a punch 18 are prepared in advance, and a bearing holder assembly 10 and a pair of bearings 2 and 3 are mounted on the upper surface and the lower surface of the bearing holder assembly 10. In the arranged state, the guide bar 16 is inserted through the bearing 3, the bearing holder assembly 10, and the bearing 2 in this order. Next, as shown in FIG. 11, by lowering the punch 18 and pressing the bearing 2, the bearings 2 and 3 are almost simultaneously pressed into the through hole 4A in the insulating holder 4. Subsequently, as shown in FIG. 12, by pulling the guide bar 16 downward and returning the punch 18 upward, the bearing assembly 14 in which the pair of bearings 2 and 3 is press-fitted and fixed in the bearing holder assembly 10 is obtained. .

Here, since the outer diameters of the bearings 2 and 3 and the inner diameter of the insulating holder 4 are press-fitted and fixed, a tight fit is obtained. The outer diameter of the guide bar 16 is set to be slightly smaller than the inner diameters of the bearings 2 and 3.

According to such a press-fitting and fixing method, the pair of bearings 2 and 3 can be press-fitted into the through-hole 4A in the insulating holder 4 at substantially the same time by using one guide bar 16, so that it is simple and inexpensive in a short time. It is possible to obtain advantages such as that it can be assembled using various assembling devices and that the coaxiality accuracy of the inner diameters of the pair of bearings 2 and 3 is very good.

[0007]

[Problems to be solved by the device]

 By the way, the conventional motor has an advantage that it can be assembled by a simple method, but has the following problems. (1) When a sintered metal or a resin material is used as the bearings 2 and 3, if the press-fitting margin between the bearings 2 and 3 and the insulating holder 4 is large, the inner diameters of the bearings 2 and 3 may be slightly different. Since the contraction occurs, the bearings 2 and 3 are in a state in which the guide bar 16 is tightened. Therefore, when the guide bar 16 is pulled out, the fixing position of the upper bearing 2, in particular, is displaced as shown in FIG. As a result, not only the appearance of the motor becomes poor, but also noise during rotation is increased and the life is shortened.

(2) Since the clearance of the outer diameter of the guide bar 16 with respect to the inner diameter of the bearing 2 is set to be extremely small, the inner peripheral surface 2A of the bearing 2 is different from the motor mounting surface 5A of FIG. Will tilt. Therefore, the verticality of the shaft 1 with respect to the motor mounting surface 5A becomes poor. Alternatively, even if the motor has a high degree of verticality, the synthetic resin forming the insulating holder 4 causes a creep phenomenon depending on the lateral pressure applied to the shaft 1 at the time of rotation and the environmental conditions. As the inner peripheral surface 2A is inclined, the verticality deteriorates due to this.

(3) Since the shaft 1 and the yoke plate 5 are electrically connected via the insulating holder 4, for example, when a pulley is attached to the shaft 1 and a rubber belt or the like is attached to the shaft 1, the shaft 1 and the yoke plate 5 are rotated. The static electricity generated by the friction of the rubber belt charges the pulley. Therefore, this static electricity causes noise. Alternatively, electromagnetic wave noise generated inside the motor is scattered outside the motor using the shaft 1 as an antenna.

The present invention has been made to solve the above problems, and it is intended to prevent the fixed position of the bearing from being displaced, improve the verticality of the shaft, and prevent the influence of noise. It is intended to provide.

[0011]

[Means for Solving the Problems]

 In order to achieve the above object, the present invention provides a motor in which a metallic bearing that rotatably supports a shaft is held by an insulating holder, and a rotor portion is fixed to the shaft. The yoke plate is protruded from the inner peripheral surface of the above and is brought into contact with the bottom surface of the metallic bearing.

[0012]

[Action]

 Since the yoke plate protruding from the inner peripheral surface of the insulating holder is in contact with the bottom surface of the bearing, the fixed position of the bearing cannot be removed. In addition, since the yoke plate is in contact with the bottom surface of the bearing, the inclination of the inner peripheral surface of the bearing with respect to the motor mounting surface can be improved, so that the verticality of the shaft can be improved. Further, since the bearing and the yoke plate are electrically connected, they are grounded without being charged even if static electricity is generated, so that the influence of noise can be prevented.

[0013]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing an embodiment of a motor of the present invention. 1 is a shaft, 2 and 3 are a pair of metallic bearings, 4 is an insulating holder, 5 is a yoke plate, 6 is a core 7 and a coil 8. The rotor part is the same as the conventional example shown in FIG.

Here, the yoke plate 5 has a planar structure and a cross-sectional structure as shown in FIGS. That is, FIGS. 2 and 3 show the structure of the yoke plate 5 before assembly, in which the central portion of the circular shape is concave, and the through hole 5B is formed therein. Further, around the through hole 5B, a plurality of, for example, three guide holes 5C for allowing the synthetic resin to flow and molding the insulating holder 4 are formed. 4 and 5 show a plan view and a cross-sectional view after the insulating holder 4 is formed.

Here, assuming that the diameter of the shaft 1 in the insulating holder 4 is D1 and the outer diameter of each of the bearings 2 and 3 is D2, the diameter D of the through hole 5B usually has a relationship of D2> D> D1. Is set to be. However, when radial ball bearings are used as the bearings 2 and 3, when the diameter of the inner ring of the radial ball bearing is D3, the diameter D of the through hole 5B has a relationship of D> D3. By injecting a synthetic resin into the yoke plate 5 through the guide hole 5C, the insulating holder 4 is formed integrally with the yoke plate 5 as shown in FIGS. As a result, the yoke plate 5 has a structure protruding to the inner peripheral surface of the through hole 4A of the insulating holder 4. Reference numeral 5D denotes an end surface of the protruding portion of the yoke plate 5, which serves as a fixed surface when the bearing 2 is press-fitted in a later step.

Next, by applying the method as shown in FIGS. 10 to 12 to the bearing holder assembly 10 thus configured, a pair of through holes 4 A in the insulating holder 4 is formed. The bearings 2 and 3 are press-fitted and fixed to form the bearing assembly 14 as shown in FIG. As is clear from FIG. 6, the bottom surface 2B of the bearing 2 is fixed by being brought into contact with the end surface 5D of the yoke plate 5. That is, the end surface 5D of the yoke plate 5 functions as a stopper for the bearing 2.

According to the motor of this embodiment, the following effects can be obtained. (1) When a sintered metal or a resin material is used for the bearings 2 and 3, even if the bearings 2 and 3 are in a state in which the guide bar 16 is tightened, the end surface 5D of the yoke plate 5 serves as a stopper. Since it works, it is possible to prevent the fixed position of the bearing 2 from being displaced as shown in FIG. As a result, the appearance of the motor is eliminated, noise during rotation is suppressed, and the life is extended.

(2) Since the bearing 2 is in contact with and fixed to the end surface 5D of the yoke plate 5, the parallelism between the motor mounting surface 5A of the yoke plate 5 and the end surface 5D is relatively easy by pressing. It can be processed with high precision. Further, the inner peripheral surface 2A and the bottom surface 2B of the bearing 2 can be machined with extremely high precision. Therefore, the inner peripheral surface 2A of the bearing 2 can be fixed to the motor mounting surface 5A without tilting, and the creep phenomenon of the synthetic resin due to lateral pressure on the shaft 1 during rotation and environmental conditions can be suppressed. Therefore, the verticality of the shaft 1 can be improved.

(3) Since the shaft 1 and the yoke plate 5 are electrically connected via the bearing 2, the yoke plate 5 is grounded to the chassis so that static electricity is generated due to friction of the rubber belt during rotation. This static electricity is removed by a route from the shaft 1 to the bearing 2 to the yoke plate 5 to the chassis. Therefore, static electricity is not charged and noise is not generated. Further, the electromagnetic wave noise generated inside the motor is also removed by the same path, so that it is not scattered to the outside of the motor.

In the embodiment, three guide holes 5C are formed in the concave portion of the yoke plate 5, but any number of guide holes 5C can be selected as long as it is one or more. Alternatively, the through hole 5B may be provided as a notch. Further, although the bearing 2 is shown as an example in which it comes into contact with the end surface 5D of the yoke plate 5, a similar structure can be adopted for the other bearings 3. Furthermore, the present invention is not limited to the brushed motor, and the same effect can be obtained when applied to a brushless motor, a coreless motor, or the like.

[0021]

[Effect of device]

 As described above, according to the present invention, the yoke plate is projected on the inner peripheral surface of the insulating holder, and the metal plate is brought into contact with the yoke plate to ground the yoke plate. It is possible to prevent deviation of the fixed position of the shaft, improve the verticality of the shaft, and prevent the influence of noise.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a motor of the present invention.

FIG. 2 is a plan view showing a yoke plate used in this embodiment.

3 is a cross-sectional view taken along the line AA of FIG.

FIG. 4 is a plan view showing a bearing holder assembly used in this embodiment.

5 is a cross-sectional view taken along the line AA of FIG.

FIG. 6 is a sectional view showing a structure in which a bearing is press-fitted and fixed to a bearing holder assembly in the present embodiment.

FIG. 7 is a cross-sectional view showing a conventional motor.

FIG. 8 is a plan view showing a bearing holder assembly used in a conventional example.

9 is a cross-sectional view taken along the line AA of FIG.

FIG. 10 is a sectional view showing a method of press-fitting and fixing a bearing in a bearing holder assembly in a conventional example.

FIG. 11 is a cross-sectional view showing another method of press-fitting and fixing the bearing in the bearing holder assembly in the conventional example.

FIG. 12 is a cross-sectional view showing another method of press-fitting and fixing the bearing in the bearing holder assembly in the conventional example.

FIG. 13 is a cross-sectional view for explaining a conventional defect.

[Explanation of symbols]

 1 Shaft 2, 3 Bearing 4 Insulating Holder 4A Through Hole 5 Yoke 5A Motor Mounting Surface 5B Through Hole 5C Guide Hole 5D End Face 10 Bearing Holder Assembly 14 Bearing Assembly 16 Guide Bar 17 Die 18 Punch

Claims (1)

[Scope of utility model registration request] 1. A motor comprising a metal bearing, which rotatably supports a shaft, which is rotatably supported by an insulating holder, and a rotor portion fixed to the shaft, wherein a yoke plate projects from an inner peripheral surface of the insulating holder. A motor characterized by being brought into contact with the bottom surface of the metallic bearing.