GB2272028A

GB2272028A - Motor mounting bearing structure

Info

Publication number: GB2272028A
Application number: GB9320748A
Authority: GB
Inventors: Hiroshi Sakashita; Jun Yamashita
Original assignee: Nidec Sankyo Corp
Current assignee: Nidec Sankyo Corp
Priority date: 1992-10-09
Filing date: 1993-10-08
Publication date: 1994-05-04
Anticipated expiration: 2013-10-08
Also published as: GB9320748D0; JPH0636340U; CN1086933A; JP2578623Y2; GB2272028B; CN1029342C; MY114760A

Abstract

A motor mounting assembly employs a shaft 1 rotatably supported by a bearing 2 composed of a disc-like flange member 2A with through holes 2B or notches (Fig. 4). A bottom surface 2D of the flange member 2A serves for mounting a device. A housing 5 surrounds the shaft 1 and the bearing 2 with a top surface (2E, Fig. 2), of the flange member 2A being secured to the housing 5. The housing 6, has reinforced projections 6B with screw holes 6A which align with the through holes 2B in the flange member 2A and can receive screws used to fasten the device to the flange member 2A. The bearing may be an oil impregnated metal powder sintered bearing. <IMAGE>

Description

MOTOR MOUNTING STRUCTURE BACRGROUND OF THE INVENTION Field of the invention The invention relates to a motor mounting structure for use in various electronic devices.

Related art A motor mounting structure such as showy in Figure 6 is knows as a conventional example. A rotating shaft 11 is rotatably supported by a bearing 12. The bearing 12 is fixed on a housing 16 by press fitting. A rotor core 13 is fixed on the rotating shaft 11, and the rotor core 13 is wound by a coil 14. A stator magnet 17 is fixed on the internal circumference of the housing 16 so as to confront the rotor 13. The upper surface of the housing 16 is covered with a side plate 18.

From the side plate 18 projects a support member 20 for supporting a brush 19. The brush 19 is arranged so as to be in slidable contact with a commutator- 15 fixed on the rotating shaft 11. Machine screw holes 16B are arranged on a bottom surface 16A of the housing 16. The bottom surface 16A serves as a surface for mounting a motor on a desired electronic device with machine screws. Figure 7 is a perspective view showing the bearing 12. A shaft insertion hole 12C for inserting the rotating shaft 11 is arranged in the middle of the bearing 12.

Figure 8 shows another exemplary conventional motor mounting structure. As shown in Figure 9, a bearing 22 has a disc-like flange part 22A. Machine screw holes 22B are arranged on the flange part 22A. The bearing 22 is fixed b engagement of the outermost circumference of the flange part 22A with a housing 16. A bottom surface 22C of the bearing 22 serves as a surface for mounting a motor on a desired electronic device with machine screws.

Either structure of Figure 6 or 8 is commonly shown as mounting a motor on a desired electronic device with the bottom surface 16A of the housing 16 or the bottom surface 22C of the bearing 22 as the mounting surface so that the output of the motor can be transmitted from the rotating shaft 11 to a load.

Here, the motor is used as a source for driving various electronic devices such as acoustic devices and information devices for tape recorders, compact discs, and floppy discs.

To mount a motor on various types of electronic devices, what bears importance is the verticality between the rotating shaft 11 and the mounting surface of the electronic device.

By the way, the conventional motor mounting structures address the following problems.

The structure of Figure 6 has the shortcoming that the verticality between the rotating shaft and the device mounting surface is destined to be impaired because the accuracy of verticality of the bottom surface 16A of the housing 16, determined by the dimensional accuracy affected by the accumulation of dimensional errors of the respective components, has a certain limitation.

In the structure of Figure 8, external force in the thrust direction such as the total weight of a motor and, e.g., the disc clamp pressure of a compact disc player is applied to the machine screw holes 22B arranged on t:e bearing 22. If the bearing 22 is manufactured by metal powder intering, the following shortcomings are encountered.

(1) Verticality is easy to be lost because of poor holding strength.

(2) The bearing 22 is liable to cracks when the machine screws are tightened onto the machine screw holes 22B.

(3) Noise and abnormal rotation are caused because powdered chips of the bearing material enter into the motor at the time of tightening the machine screws.

Further, since force is applied to a part at which the bearing 22 is engaged with the housing 16, a sufficient large fixing strength is provided for such engaging part.

SUMMARY OF THE INVENTION The invention has been made in view of the above circumstances. Accordingly, the object of the invention is to provide a motor mounting structure that can overcome the problems encountered.by the conventional examples.

According to an aspect of the present invention, there is provided a motor mounting structure or assembly comprising: a rotatable shaft; a bearing for rotatably supporting the shaft, the bearing having a disc-like flange member with a through passing means having a bottom surface for mounting a device; and a housing for surrounding the shaft and the bearing with a top surface of the flange member being secured to the housing.

Preferably the through passing means in the flange member, which may be holes or notches, align with screwthreaded holes in the housing. These holes can be provided in reinforced projections or bearing parts.

The motor can be mounted on a desired electronic device by engaging screws into the machined screw holes. The through-holes or notches arranged on the bearing simply confront the screw holes arranged on the housing and no force is imparted to the bearing. The verticality between the shaft and the mounting surface of the electronic device can be maintained and undesirable influences upon the bearing can be obviated.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a sectional view showing a motor mounting structure, which is a first embodiment of the invention; Figure 2 is a perspective view showing a main part of Figure 1; Figure 3 is a sectional view showing a second embodiment of the invention; Figure 4 is a perspective view showing a third embodiment of the invention; Figure 5 is a perspective view showing a fourth embodiment of the invention; Figure 6 is a sectional view showing a conventional example; Figure 7 is a perspective view showing a main part of Figure 6; Figure 8 is a sectional view showing another conventional example; and Figure 9 is a perspective view showing a main part of Figure 8.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the invention will hereunder be described with reference to the drawings.

Figure 1 is a sectional view showing a motor mounting structure, which is the first embodiment of invention. In Figure 1, reference numeral 1 designates a rotating shaft; and 2, a bearing rotatably supporting the rotating shaft 1. As shown in Figure 2, the bearing 2 has a disc-like flange part 2A and a plurality of through-holes 2B. In the middle of the bearing 2 is an insertion hole 2C. The bearing 2 is an oil impregnated metal powder sintered bearing. A bottom surface 2D of the flange part 2A which becomes the surface on which to mount a desired electronic device is formed vertically relative to the axial line X of the rotating shaft 1.

A rotor core 3 and a commutator 5 are fixed on the rotating shaft 1. A coil 4 is wound around the rotor core 3.

The bottom surface 2D of the bearing 2 and a top surface 2E are fixed on a housing 6 sewing as a case by press fitting, caulking, or the like. Machine screw holes 6A are arranged at positions corresponding to the through-holes 2B of the bearing 2 of the housing 6. Reference iaracter 6B designates a projection a bearing part for the holes 6A.

Reference numeral 7 designates a stator magnet arranged on the inner circumference of the housing 6 so as to confront the rotor core 3; 8, a side plate covering the upper part of the housing 6; 9, a brush arranged so as to be in slidable contact with the commutator S; and 10, a support member, one end of which supports the brush 9 and the other end of which projects from the side plate 8. The housing 6 is made of a metallic material that is press-formed or the like.

The thus structured motor is mounted on the desired electronic device by inserting not shown machine screws from the through-holes 2B and screwing the machine screws into the machine screw holes 6A by force with the through-holes 2B of the bearing 2 being set to confront the machine screw holes 6A of the housing 6.

According to the first embodiment, by using the bearing 2 that is formed so that the bottom surface 2D of the flange part 2A thereof, which is the surface to be mounted on an electronic device, is arranged so as to be vertical relative to the axial line of the rotating shaft 1, the verticality between the rotating shaft 1 and the mounting surface can be determined only by the bearing 2. Therefore, the motor mounting structure of the invention, free from dimensional errors of the other parts, prevents the verticality between the rotating shaft 1 and the mounting surface of the device from being impaired.

Further, since each machine screw is not thightened onto the bearing 2, but onto the corresponding machine screw hole 6A provided on the housing 6 that is made of a metallic material, its influence on the bearing 2 can be prevented. This means that a sufficient fixing rigidity can be obtained over the entire period in which the device is used from the initial use.

More specifically, the advantages of the invention are as follows.

(1) The holding strength is not impaired, nor is the accuracy of verticality lost.

(2) The bearing 2 is not cracked since the machine screws are not tightened onto the bearing 2.

(3) Noise or abnormal rotation are not likely to occur since the chipped powder of the bearing material is not produced.

(4) No force other than the force for supporting the rotating shaft 1 is applied to the part at which the bearing 2 is engaged with the housing 6. In addition, the strength for fixing the bearing 2 on the housing 6 is increased by mounting the motor on the electronic device. Thus, such a fixing strength as to bear the motor tare and external forces in the thrust direction is not required. As a result, structures and forming processes for improving the fixing strength can be dispensed with; thereby contributing to implementing a reduction in manufacturing cost.

Figure 3 shows a second embodiment of the invention.

This is an example in which the bearing parts 63 of the housing 6 are arranged outside. This embodiment also provides the same advantages only with the direction of the bearing parts 63 being different.

Figure 4 shows a third embodiment of the invention.

This is an example in which notches 2F are arranged on the flange part 2A instead of the through-holes 2A. Further, Figure 5 shows a fourth embodiment of the invention. This is an example in which a spigot joint part 2G is arranged in the vicinity of the bearing insertion hole 2C of the flange part 2A to improve the accuracy of fixing position of the rotating shaft 1. In addition, the fourth-embodiment is shown as having a plurality of mounting surfaces 2D, instead of a single mounting surface. The third and fourth embodiments can provide the same advantages as those of the first and second embodiments.

The number of through-holes 2B or notches 2F of the bearing 2 is not necessarily plural, but may be one at the least. - The bearing parts 6B arranged on the housing 6 may be dispensed with.

As described in the foregoing pages, the invention is shown as mounting the motor on a desired electronic device by forcing the machine screws into the machine screw holes while causing the through-holes arranged on the bearing to confront the machine screw holes arranged on the housing. Therefore, not only the verticality between the rotating shaft and the mounting surface of the electronic device can be prevented from being impaired, but also influences upon the bearing can be obviated.

Claims

1. A motor mounting structure or assembly comprising: a rotatable shaft; a bearing for rotatably supporting the shaft, the bearing having a disc-like flange member with through passing means and a bottom surface for mounting a device; and a housing for surrounding the shaft and the bearing with a top surface of the flange member being secured to the housing

2. A motor mounting assembly as claimed in claim 1, wherein the through passing means comprises a plurality of through holes.

3. A motor mounting assembly as claimed in claim 1, wherein the through passing means comprises a plurality of notches.

4. A motor mounting assembly as claimed in claim 1, 2 or 3 wherein the housing has screw threaded holes which align with the through passing means of the flange member and receive screws used to secure the device to the assembly.

5. A motor mounting assembly as claimed in claim 4, wherein the housing has projections in which the screwthreaded holes are formed.

6. A motor mounting assembly as claimed in any one of claims 1 to 4, wherein the bearing is made of oil impregnated metal powder and the housing is made of metal.

7. A mounting structure or assembly substantially as described with reference to, and as illustrated in any one or more of Figures 1 to 5 of the accompanying drawings.