JPH02114849A - Hollow motor - Google Patents

Abstract

PURPOSE:To reduce the number of parts and to simplify the structure by bearing a roller in radial direction and thrust direction by means of an inclining face at the outer circumferential or inner circumferential side of an inside tubular body and stopping the roller by means of a stopper arranged on the outside or inside tubular body. CONSTITUTION:A ball 15 constituting a roller is held at a predetermined circumferential position by means of a retainer 16. The ball 15 is born in the radial and thrust directions by means of an inclining face 17 formed at the outer circumferential or inner circumferential edge section of a rotor magnet 12. Furthermore, the ball 15 is stopped by means of a stop ring 18 such that the ball 15 is stopped by means of the inclining face 19 of the ring 18. By such arrangement, the ball 15 can bi assembled from the side face resulting in reduction of the number of parts and simplification of the structure.

Description

[Detailed description of the invention]

[Field of industrial application] The present invention relates to a hollow motor whose center side is hollow.
In particular, the present invention relates to a hollow motor suitable for application to a stepping motor using permanent magnets. K Overview of the invention Σ In a hollow PM (permanent magnet) type stepping motor,
An outer race is provided at the edge of the stator coil,
A rotor magnet is formed with inclined surfaces supporting bearing balls at both ends, and the rotor magnet is rotatably supported by a plurality of balls held by a retainer.The rotor magnet is hollow inside and simple. The present invention relates to a stepping motor having a bearing structure.

[Prior Art] j The structure of a conventional hollow PM (permanent magnet) type stepping motor is disclosed, for example, in Japanese Patent Laid-Open No. 117589/1989. As shown in FIG. A pair of stator coils 1 are arranged on the sides and supported by a stator core 2. A rotor magnet 3 is arranged with respect to the stator coil 1 through a small air gap. An inner race 4 is coupled to the magnet 3, and a V formed on the outer peripheral surface of the inner race 4 is connected to the magnet 3.
A ball 6 rolls on the groove 5. The outer peripheral side of the ball 6 is adapted to be received by an outer race 7, and a presser ring 8 is attached to the outer race 7. This holding ring 8 prevents the ball 6 from falling off. [Problems to be solved by the K invention] As described above, the conventional hollow PM type stepping motor has the following problems:
The rotor magnet 3 is fixed to the bearing inner ring part 4 provided with the groove 5, and the balls 6 are fixed by the fixed side bearing part 7 and the retaining ring 8.
I was trying to hold back. Therefore, the number of parts is large, and the work of inserting the ball 6 into the V-groove 5 is difficult. In addition, the bearing inner ring 4 and the rotor magnet 3 must be concentric, and if this concentricity is low, uneven rotation will occur.
. The present invention was made in view of these problems, and provides a hollow motor with a simple structure in which the rolling elements of the bearing that supports the rotor can be easily inserted and assembled, the number of parts in the bearing part is small, and the structure is simple. The purpose is to provide Means for Solving Problem K] The present invention comprises an inner cylindrical body and an outer cylindrical body, one of the pair of cylindrical bodies forming a rotor and the other forming a stator. Moreover, an inclined surface is formed on the outer peripheral side and edge side of the inner cylindrical body, and the rolling element is received by the slanted surface in the radial direction and the thrust direction. The rotor is held down by the presser provided. 1. Function) 1 Therefore, according to such a 4M structure, the rotor is held down by the inclined surface of the outer peripheral edge of the inner cylindrical body. To be supported,
The rollers can be inserted and assembled from the side, and the bearing can then be assembled by assembling the presser from the side. Therefore, it is possible to obtain a hollow motor having a bearing with a small number of parts and a simple structure. K Embodiment FIG. 1 shows a hollow motor according to a first embodiment of the present invention, and this hollow motor is composed of a pair of stator coils 11 and a rotor magnet 12. The stator coil 11 is held by a stator yoke 13 having pole teeth formed on its inner peripheral surface, and the rotor magnet 12 is rotatably supported by the stator yoke 13 via a ball bearing 14. . The thickness of the stator coil 111115 and rotor magnet 12 in the radial direction is extremely thin.
This results in a hollow motor with a small radial dimension and a large hollow part inside. Next, the structure of the ball bearing 14 that rotatably supports the rotor magnet 12 will be explained with reference to FIGS. 1 and 2.
is made of a non-magnetic material such as ceramic, and is held at a predetermined position in the circumferential direction by a retainer 16.The balls 15 are formed on the outer peripheral surface of the rotor magnet 12 and are located on the edge side The ball 15 is supported in the radial and thrust directions by an inclined surface 17 formed in the part.
This ring 18
The inclined surface 19 of the ball 15 presses the ball 15. In this way, the hollow PM type stepping motor I;1 according to the present embodiment, and the yoke 13 which also serves as the case on the outer peripheral side thereof.
is designed to hold one stator coil and a retaining ring 18, and the rotor magnet 12 is held by a retainer 16.
The stator coil 11 is supported at both ends in the axial direction by a plurality of balls 15 held by the stator coil 11 so that the air gap with the stator coil 11 is constant. Slanted surfaces 17 are formed at both ends of the magnet 12, and support the balls 15 by working together with the inclined surfaces 19 of the retaining ring 18, and the balls 15 are held at equal intervals in the circumferential direction by a retainer 16. ing. The presser ring 18 is bonded to the case 13 after applying pressure from the side. Therefore, according to this structure, since the balls 15 constituting the rotor are supported by the inclined surface 17 of the rotor magnet 12, it is possible to insert and assemble the balls 15 from the side, and the assembly work is facilitated. Become. In addition, the rotor magnet 12 now covers a part of the bearing,
Moreover, since this inclined surface 17 can be formed during molding, it is possible to reduce the number of bearing parts. Furthermore, by manufacturing the ball 15 from ceramic, stainless steel, chromium molybdenum steel, hard plastic, or the like, it becomes possible to directly support the magnet 12 by the ball 15 made of a nonmagnetic material. Next, a second embodiment will be explained with reference to FIGS. 3 and 4. In this embodiment, the relationship between the rotor and the stator is reversed from that of the first embodiment, and the magnet 1 on the outer circumferential side
2 constitutes the stator, and the inner coil 11
constitutes the rotor. The rotor coil 11 is rotatably supported by bearings 14 on both sides. Ball 1 of bearing 14
Reference numeral 5 denotes presser feet which are received by the inclined surface 17 formed on the edge side of the outer circumferential side of the rotor yoke 13, are arranged at equal intervals in the circumferential direction by the retainer 16, and are attached to both ends of the stator magnet 12. It is pressed down by a ring 18. Therefore, also in this embodiment, since the rolling balls 15 are received by the inclined surface 17 of the rotor yoke 13, as shown in an enlarged view in FIG. 4, it is possible to incorporate the balls 15 from the side. Further, since the rotor yoke 13 has a part of the bearing function, by also forming the inclined surface 17 when manufacturing the rotor yoke 13, it is possible to reduce the number of parts for the bearing portion. In this embodiment, since the balls 15 are not directly received by the stator magnet 12, they do not necessarily have to be made of magnetic material, and can be made of steel balls. Effects of the Invention I As described above, the present invention forms an inclined surface on the outer peripheral side and edge side of the inner cylindrical body, receives the rolling element in the radial direction and the thrust direction by the inclined surface, and The rotor is held down by a presser provided on the cylindrical body. Therefore, according to such a structure, it is possible to provide a hollow motor having a bearing with a simple structure and with a small number of parts, in which assembly of the rolling elements constituting the bearing is easy. In addition, by using balls made of non-magnetic material as rolling elements, it becomes possible to directly support the magnets with these balls, making it possible to simplify the bearing structure of hollow motors that use magnets as rotors. become.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view of a hollow motor according to a first embodiment of the present invention, FIG. 2 is an enlarged cross-sectional view of the same bearing portion, and FIG. FIG. 4 is an enlarged sectional view of the same bearing portion, and FIG. 5 is a longitudinal sectional view of a conventional hollow motor. The names of the main parts in the drawings are as follows.・Coil magnet] ・Yoke ・Ball bearing ・Ball ・Retainer ・Slanted surface ・Pressure ring ・Slanted surface

Claims (1)

[Claims] 1. Consisting of an inner cylindrical body and an outer cylindrical body, one of the pair of cylindrical bodies constitutes a rotor and the other constitutes a stator, and forming an inclined surface on the outer peripheral side of the cylindrical body and on the edge side, and receiving the rolling element in the radial direction and the thrust direction by the inclined surface;
A hollow motor characterized in that the rotor is held down by a presser provided on the outer cylindrical body. 2. The hollow motor according to claim 1, wherein the rotor is a ball made of a non-magnetic material.