JPH0736583U - Motor magnet holding structure - Google Patents

Abstract

(57) [Abstract] [Purpose] To facilitate the assembly of the holding structure of the permanent magnet for field arranged on the inner peripheral surface of the cylindrical yoke with a simple structure. Arranged on the bottom surface of the yoke 1 to hold a pair of arc-shaped permanent magnets 2 arranged symmetrically with respect to the motor axis on the inner peripheral surface of the yoke 1 having a bottomed cylindrical shape of the motor. The magnet holder 3 is sandwiched by a magnet holder 3 and a spacer 4 which insulates the brush from the magnet holder 3 and is prevented from rotating by an extension arm 3a of the magnet holder. The spacer and the magnet holder are provided with elliptical annular grooves 8 and 9, and the axial direction edge of the elastic magnet cover 5 having a cylindrical shape in a natural state is inserted into the annular groove to retain the elliptical shape, and the elastic restoring force thereof is applied. The permanent magnet is biased and fixed to the inner peripheral surface of the yoke. [Effect] The permanent magnet can be fixed by the one-part magnet cover, and the structure can be simplified and the number of parts can be reduced.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a magnet holding structure for a motor, and more particularly to a magnet holding structure for a motor in which a magnet cover is provided on the inner peripheral side of a permanent magnet for a field disposed on the inner peripheral surface of a cylindrical yoke.

[0002]

[Prior art]

 There are various types of motors, but in a permanent magnet field type motor in which a plurality of arc-shaped permanent magnets are arranged on the inner peripheral surface of a cylindrical yoke, for example, positioning of magnets and rotation prevention are performed. For this reason, some of them have been processed by projecting a boss in an appropriate place on the yoke. Further, in some cases, in which a magnet cover is provided on the inner peripheral side of the magnet in order to prevent the fragments of the magnet from falling into the armature, a permanent magnet and a magnet cover are bonded together.

A problem arises in that an additional press die for the yoke is required when the boss portion is projectingly provided on the yoke, and the number of steps in the assembly process is increased when the permanent magnet and the magnet cover are bonded together. was there. Further, as disclosed in Japanese Utility Model Publication No. 49-133709, there is a resin ring-shaped frame in which a column is simply planted. However, in this configuration, the magnet cannot press the yoke, Furthermore, there is a problem that when the magnet is broken, the fragments reach the armature.

[0004]

[Problems to be solved by the device]

 In view of such problems of the conventional technology, the main object of the present invention is to provide a motor having a simple structure, easy to assemble, and capable of preventing fragments from reaching the armature when the magnet is broken. It is to provide a magnet holding structure.

[0005]

[Means for Solving the Problems]

 According to the present invention, such a purpose is to provide a permanent magnet for a field disposed on the inner peripheral surface of a cylindrical yoke, a magnet cover provided on the inner peripheral side of the permanent magnet, and the cylindrical shape. A spacer provided to insulate the yoke and the brush from each other, and the magnet cover is made of an elastic body and is formed to have a substantially cylindrical shape in a natural state. It is achieved by providing a magnet holding structure for a motor, characterized in that a circumferential groove that can be inserted is provided by deforming one axial edge against the elastic restoring force into an elliptical shape. . Particularly, in order to prevent the permanent magnet from rotating in the circumferential direction, the other end of the magnet cover in the axial direction is resisted against the elastic restoring force on the magnet holder arranged at a position facing the spacer. It is preferable that a circumferential groove that can be inserted by being deformed into an elliptical shape is provided.

[0006]

[Action]

 In this way, one end of the magnet cover, which is a one-piece magnet cover made of an elastic body having a natural cylindrical shape in the natural state, is inserted into the elliptical circumferential groove provided in the spacer to assemble the magnet cover. The cover can be made into an elliptical shape and set on the inner peripheral side of the permanent magnet, and the permanent magnet can be pressed and fixed to the inner peripheral surface of the yoke by the elastic restoring force of the magnet cover. It can prevent debris from reaching the armature when the magnet breaks.

[0007]

【Example】

 Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a partially exploded vertical sectional view of a permanent magnet field type motor to which the present invention is applied, showing the state before the armature is incorporated. In FIG. 1, for example, a pair of permanent magnets 2 each having an arc shape are arranged on the inner peripheral surface of a yoke 1 forming a bottomed cylindrical motor casing at symmetrical positions with respect to the motor axis.

The permanent magnets 2 are provided between the magnet holder 3 provided between the bottom surface of the yoke 1 (right side in FIG. 1) and the opening surface of the yoke 1 (left side in FIG. 1). It is arranged so as to be sandwiched between the spacer 4 and the spacer 4. A cylindrical magnet cover 5 is attached to the inner peripheral sides of both permanent magnets 2 so as to cover the inner peripheral surfaces of the permanent magnets 2. The magnet cover 5 is made of, for example, a leaf spring material as an elastic body, is formed to have a cylindrical shape in a natural state, and is separated at one position in the circumferential direction in this embodiment. A disc-shaped bracket 6 that closes the opening surface is attached to the opening end of the yoke 1, and a pair of brushes 7 is provided on the motor inner end surface of the bracket 6 in the present embodiment. ing.

As shown in FIG. 2, which is an exploded perspective view of the yoke 1, the permanent magnet 2, the magnet holder 3, the spacer 4, and the magnet cover 5 described above, a pair of magnet holders 3 are provided. Two axially extending arms 3a for positioning the permanent magnet 2 in the circumferential direction are formed.

The spacer 4 is used for insulation between the yoke 1 and the brush 7, and is shown in FIG. 3, which is an end view of the spacer 4 taken along the line III-III in FIG. As also shown, it is formed in a substantially cylindrical shape, and a pair of arcuate recessed portions 4a is formed at the outer end portion in the assembled state. The arcuate recessed portions 4a are used for the escape of the brush holder and the pigtail in the assembled state.

A pair of arc-shaped projections 4b facing the respective extension arms 3a of the magnet holder 3 are provided on the inner end surface of the spacer 4 in the assembled state, and as shown in FIG. An elliptical annular groove 8 is provided as a circumferential groove. The annular groove 8 is formed so as to traverse the arcuate projections 4b in the circumferential direction, but the inner circumferential wall of the spacer 4 is partially cut off between the arcuate projections 4b. . The spacer 4 has an axially outer end surface provided with a positioning projection 4c slightly protruding in the axial direction on a part of its outer peripheral portion, and the bracket 6 has an opposite end surface in an assembled state. An annular wall (not shown), which is partially cut away so as to form a complementary shape with the positioning projection 4c, is provided, and both of them engage with each other in the assembled state, and the spacer 6 is attached to the bracket 6. 4 is locked. Therefore, the brush holder and the permanent magnet 2 are relatively positioned via the spacer.

In this embodiment, the magnet holder 3 is also provided with the annular groove 9 as a circumferential groove formed so as to face the annular groove 8 of the spacer 4 in the assembled state, and The annular groove 9 also crosses each extending arm 3a in the circumferential direction, but the height of the inner peripheral side wall of each extending arm 3a is such that it slightly projects in the axial direction.

Next, the procedure for assembling the permanent magnet 2 and the above-mentioned components will be described below. First, one end of the magnet cover 5 in the axial direction is deformed into an elliptical shape against the elastic restoring force of the magnet cover 5 itself, and the elliptical deformed edge is inside the elliptical annular groove 8 of the spacer 4. Plug in. While maintaining the deformed state, the protruding ends of the arc-shaped protrusions 4 b of the spacer 4 and the protruding ends of the extending arms 3 a of the magnet holder 3 are aligned so as to abut against each other, and the other side of the magnet cover 5 is The axial edge of is deformed into an elliptical shape in the same manner as described above and inserted into the elliptical annular groove 9 of the magnet holder 3.

As described above, the magnet cover 5 is integrally assembled in a state of being sandwiched between the spacer 4 and the magnet holder 3 in the axial direction. In that state, a pair of arch-shaped recesses having the outer peripheral surface of the magnet cover 5 as the bottom face are formed at symmetrical positions between the pair of extending arms 3a in the circumferential direction, so that these recesses are filled. The pair of permanent magnets 2 is set as described above. The unit with the permanent magnet 2 set therein is coaxially inserted into the yoke 1, and the magnet holder 3 is pushed in until it abuts on the bottom surface of the yoke 1 for setting.

After assembling a rotor (not shown), the bracket 6 on which the brush 7 is set in advance is superposed on the opening end surface of the yoke 1, and the outward flange portion of the outer peripheral portion of the opening side of the yoke 1 is provided. The bracket 6 is fixed to the yoke 1 using the screw holes.

In the motor assembled in this way, both permanent magnets 2 for the field are arranged in the axial direction of the yoke 1 on the bottom surfaces of both annular grooves 8 and 9 of the spacer 4 and the magnet holder 3. And is circumferentially positioned by the circumferential end faces of the arcuate projection 4a of the spacer 4 and the extending arm 3a of the magnet holder 3. Then, in the radial direction of the yoke 1, each permanent magnet 2 is resiliently elastically attached to the inner peripheral surface of the yoke 1 by the elastic restoring force of the magnet cover 5 deformed into an elliptical shape in the direction of arrow A in FIG. Since the magnet is pressed and positioned, the magnet does not rattle, and the broken pieces of the magnet do not reach the armature, and the permanent magnet 2 is fixed in the yoke 1.

In the present embodiment, the magnet cover 5 has a shape in which a part of the magnet cover 5 is separated in the circumferential direction, but it may be formed in a cylindrical shape which is not separated, and in any case, 1 A cylindrical magnet cover made of parts can be used to fix the field permanent magnet to the yoke. Further, in the present embodiment, the extending arm 3a of the magnet holder 3 and the protruding ends of the arc-shaped protruding portions 4b of the spacer 4 are made to abut against each other, but the annular groove 8 of the spacer 4 is fitted to the magnet cover 5. It is also possible to set the permanent magnet 2 in the state of incorporating, and set it so that the permanent magnet 2, the magnet holder 3 and the spacer 4 collide with each other and assemble.

[0019]

[Effect of device]

 As described above, according to the present invention, a magnet cover made of a one-piece substantially cylindrical elastic body is deformed into an elliptical shape by a spacer or a circumferential groove provided in a spacer and a magnet holder, and is assembled, whereby a magnet is attached. Due to the elastic restoring force of the cover, the permanent magnet can be elastically pressed and fixed to the inner peripheral surface of the yoke, and the fixing structure of the permanent magnet in the motor using the magnet cover can be simplified and the number of parts can be reduced. Can be suitably reduced.

[Brief description of drawings]

FIG. 1 is a partially exploded vertical sectional view of a permanent magnet field type motor to which the present invention is applied.

FIG. 2 is a partially exploded perspective view of a motor.

FIG. 3 is an end view taken along the line III-III in FIG.

[Explanation of symbols]

 1 yoke 2 permanent magnet 3 magnet holder 3a extended arm 4 spacer 4a arcuate recessed part 4b arcuate projection 4c positioning projection 5 magnet cover 6 bracket 7 brush 8 annular groove 9 annular groove

Claims (2)

[Scope of utility model registration request] 1. A field permanent magnet disposed on an inner peripheral surface of a cylindrical yoke, a magnet cover provided on an inner peripheral side of the permanent magnet, and a portion between the cylindrical yoke and the brush. A spacer provided to insulate the magnet cover, and the magnet cover is formed of an elastic body and has a substantially cylindrical shape in a natural state, and one end of the magnet cover in the axial direction is elastically attached to the spacer. A magnet holding structure for a motor, wherein a circumferential groove that can be inserted by being deformed into an elliptical shape against a restoring force is provided. 2. A magnet holder disposed at a position facing the spacer to prevent the permanent magnet from rotating in the circumferential direction, and the other axial end of the magnet cover resists elastic restoring force. The magnet holding structure for a motor according to claim 1, wherein a circumferential groove that can be inserted by being deformed into an elliptical shape is provided.