motor

Abstract

For example, providing a motor capable of suppressing brush vibrations. [Solution] For example, a motor (1) comprising a commutator (6), brushes (7) that contact the commutator (6), and a holder (22) that houses the brushes (7), wherein the holder (22) comprises an opening (150) that opens toward the opposite side of the commutator (6) and side walls (110, 210, 310, 410, 510) that bias the brushes (7) in the circumferential direction.

Description

Technical Field

[0001] The present invention relates to a motor.

Background Art

[0002] As a DC motor with brushes, a motor in which the brushes are housed in a holder is known. For example, in Patent Document 1, it is described that the rear end side of the brush 6 is pressed against the side wall 5b on the rotational direction side of the brush holder 5 by the inclined surface 6a of the brush 6 and the coil spring 7.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Providing a new holder structure for suppressing the vibration of the brushes leads to an increase in options for coping with various restrictions in the manufacturing process or cost of the DC motor with brushes. An example of the problem of the present invention is to provide a new motor capable of suppressing the vibration of the brushes.

Means for Solving the Problems

[0005] A motor which is an example of the present invention includes a commutator, a brush that contacts the commutator, and a holder that houses the brush, and the holder includes an opening that opens toward the opposite side of the commutator and a side wall that biases the brush in the circumferential direction.

Brief Description of the Drawings

[0006] [Figure 1] It is a perspective view of a motor which is an example of the present invention. [Figure 2] It is a schematic diagram showing a part of the configuration of a motor which is an example of the present invention. [Figure 3] This is a perspective view showing the configuration of the motor holder according to the first embodiment. [Figure 4] This is a perspective view showing the configuration of the motor holder according to the first embodiment. [Figure 5] This figure shows the motor holder, brush, and second spring according to the first embodiment. [Figure 6] This is a perspective view showing the configuration of the motor holder according to the second embodiment. [Figure 7] This figure shows the motor holder, brush, and second spring according to the second embodiment. [Figure 8] This is a perspective view showing the configuration of the motor holder according to the third embodiment. [Figure 9] This figure shows the motor holder, brush, and second spring according to the third embodiment. [Figure 10] This is a perspective view showing the configuration of the motor holder according to the fourth embodiment. [Figure 11] This figure shows the motor holder, brushes, and second spring according to the fourth embodiment. [Figure 12] This is a perspective view showing the configuration of the motor holder according to the fifth embodiment. [Figure 13] This figure shows the motor holder, brushes, and second spring according to the fifth embodiment. [Modes for carrying out the invention]

[0007] In describing embodiments of the present invention, for convenience of explanation, the direction along the rotation axis S is referred to as the rotation axis direction or axial direction. In the rotation axis direction, the direction from the commutator 6 toward the rotor 4 (arrow a direction) is referred to as one side, and the opposite direction (arrow b direction) is referred to as the other side. Furthermore, the direction of arrow cd perpendicular to the rotation axis S is referred to as the radial direction, the direction of arrow c away from the rotation axis S is referred to as the outer or one side in the radial direction, and the direction of arrow d approaching the rotation axis S is referred to as the inner or other side in the radial direction. The direction of rotation around the rotation axis S is referred to as the circumferential direction. In a certain member or part, the outer surface in the radial direction (arrow c direction) may be referred to as the outer circumferential surface, and the inner surface in the radial direction (arrow d direction) may be referred to as the inner circumferential surface.

[0008] [Common structure] First, the overall configuration of motor 1, which is an example of the present invention, will be explained using Figures 1 and 2. The overall configuration of motor 1 described below is common to all embodiments described later. However, the motor of the present invention is not limited to motor 1 shown herein, but may be any form of brushed DC motor.

[0009] As shown in Figure 1, the motor 1 comprises a rotating shaft S, a bracket 2, a case 3, a magnet (stator) M, a rotor 4, a bearing 5, a commutator 6, and brushes 7. In Figure 1, the case 3, bearing 5, and magnet M are shown with dashed lines to make the internal structure of the motor 1 easier to see. In Figure 1, the coil 42 is omitted.

[0010] The rotor 4 and commutator 6 are fixed to the outer surface of the rotating shaft S. In the axial direction, the rotor 4 is positioned on one side of the commutator 6 (in the direction of arrow a). The rotating shaft S, rotor 4, and commutator 6 rotate as a single unit.

[0011] Case 3 is a cylindrical member having a cavity inside, and an annular end portion on the other side (in the direction of arrow b) in the axial direction forms an opening of Case 3. In the axial direction, the bracket 2 is disposed on the other side (in the direction of arrow b) of the case 3, closing a part or all of the end portion of the case 3. The bracket 2 and the case 3 are integrated to form the housing H, and the rotor 4 and the commutator 6 are accommodated inside.

[0012] In the axial direction, one end portion (in the direction of arrow a) of the rotating shaft S is rotatably supported with respect to the case 3 via a bearing 5. The bearing 5 may be a ball bearing, a sleeve bearing, or various other bearings. Although not shown, in the axial direction, the other end portion (in the direction of arrow b) of the rotating shaft S may be supported by the bracket 2 via another bearing.

[0013] The magnet M is a permanent magnet fixed to the inner peripheral surface of the case 3. In the radial direction, the magnet M is disposed at a predetermined interval from the rotor 4. The magnet M is disposed so as to surround the rotor 4 from the outside (in the direction of arrow c) in the radial direction. In FIG. 1, the magnet M is illustrated as two permanent magnets having a curved shape (semicylindrical shape), but the configuration of the magnet M is not limited to that illustrated. The magnet M may be composed of a plurality of permanent magnets having a plurality of magnetic poles, or may be composed of a single annular permanent magnet having a plurality of magnetic poles. The magnet M may have a cylindrical shape.

[0014] The rotor 4 includes a magnetic body (hereinafter referred to as a core) 41 having a plurality of magnetic pole portions, and a coil 42 wound around the core 41. The coil 42 formed of a conducting wire is omitted in FIG. 1 and schematically shown in FIG. 2. In the radial direction, the rotor 4 faces the magnet M. The core 41 of the rotor 4 is fixed to the rotating shaft S and rotates integrally with the rotating shaft S.

[0015] In the direction of the rotation axis, on the other side of the rotor 4 (in the direction of arrow b), a commutator 6 having a substantially cylindrical shape is arranged. The commutator 6 is fixed to the rotation axis S and rotates integrally with the rotation axis S. The commutator 6 is configured such that a plurality of segments (commutator pieces) 61 arranged in the circumferential direction come into contact with the brushes 7 for energization. At one end (in the direction of arrow a) in the axial direction of each segment 61, a riser 62 for electrically connecting the conductor 421 constituting the coil 42 and the segment 61 is provided.

[0016] As shown in FIG. 1, the bracket 2 includes a lid 20 that covers a part or the whole of the end of the case 3, a cylindrical portion 21, two holders 22 that house the brushes 7, and two columns 23 that project in one direction (in the direction of arrow a) in the axial direction from the lid 20. The bracket 2 is formed of, for example, resin. The cylindrical portion 21 extends in one direction (in the direction of arrow a) in the axial direction inside the outer peripheral portion of the lid 20. In the radial direction, the dimension of the outer peripheral surface of the cylindrical portion 21 is the same as or slightly smaller than the dimension of the inner peripheral surface of the case 3. The outer peripheral surface of the cylindrical portion 21 is fixed to the inner peripheral surface of the case 3 by fitting, press-fitting or adhesion.

[0017] The two holders 22 are formed integrally with the bracket 2 and are connected to one side (in the direction of arrow a) in the axial direction of the lid 20. The two holders 22 are each a frame formed in a cylindrical shape that extends in the radial direction and has a plurality of corners in the circumferential direction. The two holders 22 are arranged side by side in the circumferential direction. The angle formed by the two holders 22 in the circumferential direction is not particularly limited and may be 90°, 120°, 180°, or any other angle. The two holders 22 each include an inner end (in the direction of arrow d) in the radial direction facing the commutator 6 and an outer end (in the direction of arrow c) in the radial direction. The outer end in the radial direction is connected to the cylindrical portion 21. The two holders 22 open in the outer direction (in the direction of arrow c) in the radial direction, that is, on the opposite side of the commutator 6. The detailed configuration of the holder 22 will be described later.

[0018] As shown in Figure 2, the holder 22 houses a brush 7 which has the shape of a column with multiple corners (approximately a rectangular prism). The brush 7 may be made of carbon, metal, or other conductive material. In the radial direction, the inner end of the brush 7 (in the direction of arrow d) protrudes from the holder 22 and contacts the segment 61 of the commutator 6. In the axial direction, a conductor 9 is electrically connected to one side of the brush 7 (in the direction of arrow a). The conductor 9 is connected to an external power source, etc. (not shown). When current flows from the conductor 9 connected to the power source, etc., through the brush 7, commutator 6, and coil 42 in that order, the rotor 4 and the rotating shaft S begin to rotate. As the commutator 6 rotates together with the rotating shaft S, the segment 61 that the brush 7 contacts switches, and the rotation of the rotor 4 continues.

[0019] As shown in Figure 1, the two columns 23 of the bracket 2 are positioned radially inward (in the direction of arrow d) of the cylindrical portion 21. The two columns 23 are positioned adjacent to the holder 22 in the circumferential direction. Each of the two columns 23 has one elastic member 8 (sometimes referred to as the "second spring" for convenience in relation to the first spring described later). In this embodiment, the elastic member 8 is a spring (coil spring) formed from a spirally wound metal wire. The elastic member 8 contacts the radially outer end (in the direction of arrow c) of the brush 7 and biases the brush 7 radially inward (in the direction of arrow d). In other words, the elastic member 8 biases the brush 7 radially toward the commutator 6. Therefore, the brush 7 is pre-pressurized radially toward the commutator 6 by the elastic member 8. As a result, even if the contact portion of the brush 7 with the commutator 6 wears down over time due to the use of the motor 1, the electrical connection between the brush 7 and the commutator 6 is ensured.

[0020] The following describes several specific examples of the holder 22 formed on the bracket 2 of the motor 1 as part of multiple embodiments. However, the holder provided in the motor of the present invention is not limited to any of the embodiments shown below.

[0021] [First Embodiment] First, the configuration of the holder 100 of the motor 1 according to the first embodiment will be explained using Figures 3 to 5. The holder 100 corresponds to the holder 22 described above, but in this embodiment, for convenience, it will be referred to as holder 100.

[0022] Figures 3 and 4 are perspective views showing the configuration of the holder 100. In Figure 3, hidden parts are indicated by dashed lines. In Figure 4, parts of the holder 100 (part of the second side wall 120 and part of the third side wall 130) are omitted to make the parts hidden in Figure 3 easier to see. As mentioned above, the holder 100 can be formed integrally with the bracket 2 of the motor 1, but in Figures 3 and 4, only the holder 100 is shown as an excerpt. Figure 5 shows the holder 100, brush 7, elastic member 8, conductor 9, and column 23, and is a view of the motor 1 from the outside to the inside in the radial direction (direction of arrow d in Figures 1 and 2).

[0023] As shown in Figures 3 and 4, the holder 100 has a cylindrical (approximately square cylindrical) shape with multiple corners as a whole. The holder 100 is molded from, for example, resin. For convenience, in the holder 100, one of the two side walls facing the circumferential direction of the motor 1 (the direction of rotation of the rotor) is referred to as the first side wall 110, and the other as the second side wall 120. Of the two side walls facing the axial direction of the motor 1, the side wall on one side in the axial direction (direction of arrow a) (top wall) is referred to as the third side wall 130, and the side wall on the other side in the axial direction (direction of arrow b) (bottom wall) is referred to as the fourth side wall 140. In this embodiment, the fourth side wall 140 is also part of the cover 20 of the bracket 2 (see Figure 1).

[0024] The holder 100 has an outer end 100c in the radial direction (direction of arrow c) and an inner end 100d in the radial direction (direction of arrow d). In the radial direction, the end 100c of the holder 100 is located on the case 3 side. In the radial direction, the end 100d of the holder 100 is located on the commutator 6 side. The end 100c of the holder 100 has a first opening 150 that opens radially outward (direction of arrow c) (towards the opposite side of the commutator 6). The end 100d of the holder 100 has a second opening 160 that opens radially inward (direction of arrow d) (towards the commutator 6).

[0025] The first side wall 110 is configured to bias the brush 7 in the circumferential direction of the motor 1 (the direction from the first side wall 110 toward the second side wall 120). Specifically, the first side wall 110 includes two slits 111a and 111b formed to extend radially, and a plate-shaped spring 112 (sometimes referred to as the "first spring" for convenience) provided adjacent to the two slits 111a and 111b. The spring 112 biases the brush 7 in the circumferential direction of the motor 1 (the direction of rotation of the rotor). The brush 7, biased by the spring 112, comes into contact with the second side wall 120.

[0026] The two slits 111a and 111b extend radially inward (in the direction of arrow d) from the first opening 150 formed at the end 100c of the holder 100. The radially inward (in the direction of arrow d) ends of the two slits 111a and 111b are radially outward (in the direction of arrow c) than the second opening 160 of the holder 100.

[0027] The spring 112 is a so-called leaf spring and is positioned in the axial direction between two slits 111a and 111b. The spring 112 extends radially outward (in the direction of arrow c) from near the end 100d of the holder 100. As shown in Figure 4, the spring 112 comprises, in order from the radially inward side (closer to the commutator 6), a connecting portion 112a, a portion with a larger dimension than the connecting portion 112a (hereinafter referred to as the thickened portion) 112b, and an end portion 112c. This thickened portion 112b is formed between the connecting portion 112a and the end portion 112c and constitutes the middle portion of the spring 112.

[0028] The connecting portion 112a is the part that connects the spring 112 to the other part of the first side wall 110. The connecting portion 112a is formed in a flat plate shape that extends radially and axially. The connecting portion 112a is designed to elastically deform when the spring 112 biases the brush 7.

[0029] The thickened portion 112b is the part that contacts the brush 7. In the circumferential direction, the dimensions of the thickened portion 112b are larger than the dimensions of the connecting portion 112a. On the thickened portion 112b, the surface facing the second side wall 120 (the side of the brush 7) is a curved surface 112d. As a result, the thickened portion 112b has a convex portion 112e that protrudes toward the brush 7. The thickened portion 112b is located at a predetermined distance from both the inner end 100d and the outer end 100c of the holder 100 in the radial direction. Specifically, in the radial direction, the portion of the thickened portion 112b that contacts the brush 7 is located at a distance D1 from the end 100d of the holder 100 and at a distance D2 from the end 100c of the holder 100. D1 may be in the range of 1 / 4 to 3 / 4 of D1 + D2 (the radial dimension of the holder 100), or in the range of 1 / 3 to 2 / 3, or in the range of 2 / 5 to 3 / 5. Also, in the direction of rotation, in order to adjust the biasing force of the spring 112, the width of the connecting portion 112a and the width of the thickened portion 112b may be smaller than, the same as, or larger than the width of the slit 121.

[0030] The end 112c of the spring 112 is the radially outer end (direction of arrow c). The end 112c of the spring 112 is radially inward (direction of arrow d) than the radially outer end 100c of the holder 100 (direction of arrow c).

[0031] The second side wall 120 of the holder 100 is the side wall of the bracket 2 that is closer to the column 23. A slit 121 is formed in the second side wall 120, extending radially inward (in the direction of arrow d) from the first opening 150 formed at the end 100c of the holder 100. The radially inward (in the direction of arrow d) end of the slit 121 is radially outward (in the direction of arrow c) than the radially inward end 100d of the holder 100.

[0032] Figure 5 is a view of the holder 100 from the outside in the radial direction. As shown in Figure 5, the elastic member 8 positioned on the column 23 of the bracket 2 passes through the slit 121 in the second side wall 120 and contacts the radial outer end of the brush 7. As a result, the elastic member 8 biases the brush 7 toward the commutator 6 in the radial direction. Because the second side wall 120 is provided with the slit 121, the elastic member 8 can continue to bias the brush 7 as the contact portion of the brush 7 with the commutator 6 wears down over time due to the use of the motor 1, and the radial dimensions of the brush 7 decrease.

[0033] The force with which the spring 112 biases the brush 7 is smaller than the force with which the elastic member 8 biases the brush 7. Furthermore, because the brush 7 is in contact with the first side wall 110, the second side wall 120, and the fourth side wall 140 of the holder 100, a force acts on the brush 7 that resists radial movement between it and the holder 100, in addition to the biasing force by the spring 112. This force resisting radial movement of the brush 7 (specifically, the radial static friction force generated between the brush 7 and the holder 100) is smaller than the force with which the elastic member 8 biases the brush 7. As a result, continuous contact between the brush 7 and the commutator 6 is ensured, even as the brush 7 changes in its radial dimensions.

[0034] The third side wall 130 of the holder 100 is the side wall (top wall) closest to the rotor 4. As shown in Figures 3 and 5, a slit 131 is formed in the third side wall 130, extending radially inward (in the direction of arrow d) from a first opening 150 formed at the end 100c of the holder 100 (Figures 3 and 5). The radially inward (in the direction of arrow d) end of the slit 131 is radially outward (in the direction of arrow c) than the radially inward end 100d of the holder 100.

[0035] As shown in Figure 5, the conductor 9, which is electrically connected to one side of the brush 7 in the axial direction (direction of arrow a), passes through the slit 131 in the third side wall 130. Because the third side wall 130 has a slit 131, even if the contact portion of the brush 7 with the commutator 6 wears down over time due to the use of the motor 1, and the connection point between the brush 7 and the conductor 9 moves radially, the electrical connection between the brush 7 and the external power supply, etc., is continuously maintained.

[0036] In this embodiment, the first side wall 110 of the holder 100 biases the brush 7 in the circumferential direction. As a result, vibration of the brush 7 within the holder 100 is suppressed or dampened, and the motor 1 becomes quieter. In addition, in this embodiment, the holder 100 has a first opening 150 that opens toward the opposite side of the commutator 6. Therefore, when forming the holder 100 as part of the bracket 2, the core can be pulled out radially outward during forming. For example, even if the bracket 2 has two or more holders 100, the core pulled out from one holder 100 does not interfere with the other holder 100, and it can be easily manufactured. Also, when assembling the motor 1, the brush 7 can be inserted from the radially outward side.

[0037] In this embodiment, a plate-shaped spring 112 is formed on the first side wall 110. This simplifies the manufacturing process because the biasing means for the brush 7 is formed simultaneously with the molding of the holder 100. The spring 112 has a thickened portion 112b that biases the brush 7. By changing the thickness of the thickened portion 112b, the force with which the thickened portion 112b biases the brush 7 can be adjusted. Furthermore, because the surface of the thickened portion 112b that contacts the brush 7 is curved, only a portion of the brush 7 that contacts the thickened portion 112b can be biased. In addition, because the surface of the thickened portion 112b that contacts the brush 7 is curved, the spring 112 does not hinder the movement of the brush 7 when inserting it, allowing the brush 7 to be smoothly inserted into the holder 100.

[0038] In this embodiment, the portion of the thickened section 112b that contacts the brush 7 is radially separated by a predetermined distance from both the inner end 100d and the outer end 100c of the holder 100. This allows the spring 112 to maintain an appropriate biasing force on the brush 7, and to continue biasing the brush 7 even if its radial dimensions decrease due to wear.

[0039] [Second Embodiment] Next, the configuration of the holder 200 of the motor 1 according to the second embodiment will be described with reference to Figures 6 and 7. The holder 200 corresponds to the holder 22 described above, but in this embodiment, for convenience, it will be referred to as holder 200. The holder 200 has the same configuration as the holder 100 according to the first embodiment, except that it has a first side wall 210 instead of the first side wall 110. Hereinafter, members, parts, and components that have the same function and configuration as in the first embodiment will be denoted by the same reference numerals, and their detailed descriptions may be omitted.

[0040] Figure 6 is a perspective view showing the configuration of the holder 200. In Figure 6, parts of the holder 200 (part of the second side wall 120 and part of the third side wall 130) are omitted to make the parts that would otherwise be hidden by the second side wall 120 easier to see. As mentioned above, the holder 200 can be formed integrally with the bracket 2 of the motor 1, but in Figure 6, only the holder 200 is shown as an excerpt. Figure 7 shows the holder 200, brush 7, elastic member 8, conductor 9, and column 23, and is a view of the motor 1 from the outside to the inside in the radial direction (direction of arrow d in Figures 1 and 2).

[0041] The first side wall 210 is configured to bias the brush 7 in the circumferential direction of the motor 1 (the direction from the first side wall 210 toward the second side wall 120). Specifically, the first side wall 210 includes two slits 211a and 211b formed to extend radially, and a plate-shaped spring 212 (sometimes referred to as the "first spring" for convenience) provided adjacent to the two slits 211a and 211b, and the spring 212 biases the brush 7 in the circumferential direction of the motor 1 (the direction of rotation of the rotor). As shown in Figure 7, the first side wall 210 of the holder 200 is thicker than the first side wall 110 of the holder 100 according to the first embodiment.

[0042] The two slits 211a and 211b extend radially inward (in the direction of arrow d) from the first opening 150 formed at the end 100c of the holder 200. The radially inward (in the direction of arrow d) ends of the two slits 211a and 211b are radially outward (in the direction of arrow c) than the second opening 160 of the holder 200.

[0043] The spring 212 is a so-called leaf spring and is positioned axially between two slits 211a and 211b. The spring 212 extends radially outward (in the direction of arrow c) from near the end 100d of the holder 200. As shown in Figure 6, the spring 212 comprises, in order from the radially inward side (closer to the commutator 6), a connecting portion 212a, a portion having a larger dimension than the connecting portion 212a (hereinafter referred to as the thickened portion 212b), and an end portion 212c. This thickened portion 212b is formed between the connecting portion 212a and the end portion 212c and constitutes the middle portion of the spring 212. The radial length of the connecting portion 212a is longer than that of the connecting portion 112a of the spring 112 of the holder 100 according to the first embodiment. As shown in Figure 7, in this embodiment, the spring 212 is located on the side closer to the brush 7 than the outer surface of the first side wall 210 (the surface facing away from the brush 7).

[0044] The connecting portion 212a is the part that connects the spring 212 to the other part of the first side wall 210. The connecting portion 212a is formed in a flat plate shape that extends radially and axially. The connecting portion 212a is designed to elastically deform when the spring 212 biases the brush 7.

[0045] The thickened portion 212b is the part that contacts the brush 7. In the circumferential direction, the dimensions of the thickened portion 212b are larger than the dimensions of the connecting portion 212a. On the thickened portion 212b, the surface facing the second side wall 120 (the side of the brush 7) is a curved surface 212d. As a result, the thickened portion 212b has a convex portion 212e that protrudes toward the brush 7. The thickened portion 212b is located at a predetermined distance from both the inner end 100d and the outer end 100c of the holder 200 in the radial direction. Specifically, in the radial direction, the portion of the thickened portion 212b that contacts the brush 7 is located at a distance D3 from the end 100d of the holder 200 and at a distance D4 from the end 100c of the holder 200. D3 is greater than D1 in the first embodiment. In other words, in this embodiment, the portion of the thickened section 212b that contacts the brush 7 is located further radially from the commutator 6. Alternatively, the portion of the thickened section 212b that contacts the brush 7 may also be located further radially from the end 100d and the commutator 6. The portion of the thickened section 212b that contacts the brush 7 may be located further radially from the commutator 6 with respect to the center position between the end 100c and end 100d of the holder 200, or the distance from the portion of the thickened section 212b that contacts the brush 7 to the center position may be smaller than the distance from the end 100d of the holder 200 to the portion of the thickened section 212b that contacts the brush 7 (i.e., it is near the center position).

[0046] Furthermore, in the direction of rotation, in order to adjust the biasing force of the spring 212, the width of the connecting portion 212a and the width of the thickened portion 212b may be smaller than, the same as, or larger than the width of the slit 121.

[0047] The end 212c of spring 212 is the radially outer end (direction of arrow c). The end 212c of spring 212 is radially inward (direction of arrow d) than the radially outer (direction of arrow c) end 100c of holder 200.

[0048] The force with which the spring 212 biases the brush 7 is smaller than the force with which the elastic member 8 biases the brush 7. Furthermore, because the brush 7 is in contact with the first side wall 210, the second side wall 120, and the fourth side wall 140 of the holder 200, a force acts on the brush 7 that resists radial movement between it and the holder 200, in addition to the biasing force by the spring 212. This force resisting radial movement of the brush 7 (specifically, the radial static friction force generated between the brush 7 and the holder 200) is smaller than the force with which the elastic member 8 biases the brush 7. As a result, continuous contact between the brush 7 and the commutator 6 is ensured, even as the brush 7 changes in its radial dimensions.

[0049] According to the holder 200 of this embodiment, similar to the holder 100 of the first embodiment, the motor 1 is made quieter and easier to manufacture. In addition, by changing the thickness of the thickened portion 212b, the force with which the thickened portion 212b biases the brush 7 can be adjusted. Furthermore, because the surface of the thickened portion 212b that contacts the brush 7 is curved, a portion of the brush 7 that contacts the thickened portion 212b can be biased. In addition, because the surface of the thickened portion 212b that contacts the brush 7 is curved, the spring 212 prevents the brush 7 from hindering the movement of the brush 7 when it is inserted, allowing the brush 7 to be smoothly inserted into the holder 200.

[0050] In this embodiment, the portion of the spring 212 that contacts the brush 7 is further away from the commutator 6 than in the first embodiment. This allows the force with which the spring 212 biases the brush 7 to be weaker than, for example, in the first embodiment.

[0051] [Third Embodiment] Next, the configuration of the motor holder 300 according to the third embodiment will be described with reference to Figures 8 and 9. The holder 300 corresponds to the holder 22 described above, but in this embodiment, for convenience, it will be referred to as the holder 300. The holder 300 has the same configuration as the holder 100 according to the first embodiment, except that it has a first side wall 310 instead of the first side wall 110. Hereinafter, members, parts, and components that have the same function and configuration as in the first embodiment will be denoted by the same reference numerals, and their detailed descriptions may be omitted.

[0052] Figure 8 is a perspective view showing the configuration of the holder 300. In Figure 8, parts of the holder 300 (part of the second side wall 120 and part of the third side wall 130) are omitted to make the parts that would otherwise be hidden by the second side wall 120 easier to see. As mentioned above, the holder 300 can be formed integrally with the bracket 2 of the motor 1, but in Figure 8, only the holder 300 is shown as an excerpt. Figure 9 shows the holder 300, brush 7, elastic member 8, conductor 9, and column 23, and is a view of the motor 1 from the outside to the inside in the radial direction (direction of arrow d in Figures 1 and 2).

[0053] The first side wall 310 is configured to bias the brush 7 in the circumferential direction of the motor 1 (the direction from the first side wall 310 toward the second side wall 120). Specifically, the first side wall 310 includes two slits 311a and 311b formed to extend in the axial direction, and a plate-shaped spring 312 (sometimes referred to as the "first spring" for convenience) provided adjacent to the two slits 311a and 311b, and the spring 312 biases the brush 7 in the circumferential direction of the motor 1 (the direction of rotation of the rotor).

[0054] The two slits 311a and 311b extend from the connection point between the first side wall 310 of the holder 300 and the third side wall 130 toward the other side in the axial direction (direction of arrow b). In the axial direction, the other end of the two slits 311a and 311b (direction of arrow b) is on one side (direction of arrow a) of the fourth side wall 140 of the holder 300.

[0055] The spring 312 is a so-called leaf spring and is positioned radially between two slits 311a and 311b. The spring 312 extends from the vicinity of the fourth side wall 140 of the holder 300 toward one side in the axial direction (direction of arrow a). As shown in Figure 8, the spring 312 comprises, in order from the other side in the axial direction (direction of arrow b), a connecting portion 312a, a portion having a larger dimension than the connecting portion 312a (hereinafter referred to as the thickened portion 312b), and an end portion 312c. This thickened portion 312b is formed between the connecting portion 312a and the end portion 312c and constitutes the middle portion of the spring 312.

[0056] The connecting portion 312a is the part that connects the spring 312 to the other part of the first side wall 310. The connecting portion 312a is formed in a flat plate shape that extends radially and axially. When the spring 312 biases the brush 7, the connecting portion 312a is elastically deformed.

[0057] The thickened portion 312b is the part that contacts the brush 7. In the circumferential direction, the dimensions of the thickened portion 312b are larger than the dimensions of the connecting portion 312a. The thickened portion 312b is provided with a convex portion 312e that protrudes toward the brush 7. The thickened portion 312b is located at a predetermined distance from both the inner end 100d and the outer end 100c of the holder 300 in the radial direction. Specifically, in the radial direction, the central part of the portion of the thickened portion 312b that contacts the brush 7 is located at a distance D5 from the end 100d of the holder 300 and at a distance D6 from the end 100c of the holder 300. D5 may be, for example, within the range of 1 / 4 to 3 / 4, 1 / 3 to 2 / 3, or 2 / 5 to 3 / 5 of D5 + D6 (the radial dimension of the holder 100). Furthermore, in the axial direction, the portion of the thickened section 312b that contacts the brush 7 is positioned near the center of the holder 300. In addition, the width of the connecting section 312a and the width of the thickened section 312b in the radial direction may be smaller than, the same as, or larger than the width of the slit 121 in the rotational axis direction, in order to adjust the biasing force of the spring 312.

[0058] The end 312c of the spring 312 is the end on one side in the axial direction (direction of arrow a). In the axial direction, the end 312c of the spring 312 is on the other side (direction of arrow b) of the third side wall 130 of the holder 300.

[0059] The force with which the spring 312 biases the brush 7 is smaller than the force with which the elastic member 8 biases the brush 7. Also, because the brush 7 is in contact with the first side wall 310, the second side wall 120, and the fourth side wall 140 of the holder 300, a force acts on the brush 7 between it and the holder 300 that resists radial movement in response to the biasing force by the spring 312. The force resisting radial movement of the brush 7 (specifically, the radial static friction force generated between the brush 7 and the holder 300) is smaller than the force with which the elastic member 8 biases the brush 7. As a result, continuous contact between the brush 7 and the commutator 6 is ensured, even as the brush 7 changes in its radial dimensions.

[0060] According to the holder 300 of this embodiment, similar to the holder 100 of the first embodiment, the motor 1 is made quieter and easier to manufacture. In addition, by changing the thickness of the thickened portion 312b, the force with which the thickened portion 312b biases the brush 7 can be adjusted.

[0061] According to this embodiment, when designing the motor 1, the force with which the spring 312 biases the brush 7 can be adjusted by changing the length of the connecting portion 312a of the spring 312 without changing the radial position of the portion of the spring 312 that contacts the brush 7.

[0062] [Fourth Embodiment] Next, the configuration of the holder 400 of the motor 1 according to the fourth embodiment will be described with reference to Figures 10 and 11. The holder 400 corresponds to the holder 22 described above, but in this embodiment, for convenience, it will be referred to as holder 400. The holder 400 has the same configuration as the holder 100 according to the first embodiment, except that it has a first side wall 410 instead of the first side wall 110. Hereinafter, members, parts, and components that have the same function and configuration as in the first embodiment will be denoted by the same reference numerals, and their detailed descriptions may be omitted.

[0063] Figure 10 is a perspective view showing the configuration of the holder 400. In Figure 10, parts of the holder 400 (part of the second side wall 120 and part of the third side wall 130) are omitted to make parts that would otherwise be hidden by the second side wall 120 easier to see. As mentioned above, the holder 400 can be formed integrally with the bracket 2 of the motor 1, but in Figure 10, only the holder 400 is shown as an excerpt. Figure 11 shows the holder 400, brush 7, elastic member 8, conductor 9, and column 23, and is a view of the motor 1 from the outside to the inside in the radial direction (direction of arrow d in Figures 1 and 2).

[0064] The first side wall 410 is configured to bias the brush 7 in the circumferential direction of the motor 1 (the direction from the first side wall 410 toward the second side wall 120). Specifically, the first side wall 410 includes two slits 411a and 411b formed to extend in the axial direction, and a plate-shaped spring 412 (sometimes referred to as the "first spring" for convenience) provided adjacent to the two slits 411a and 411b, and the spring 412 biases the brush 7 in the circumferential direction of the motor 1 (the direction of rotation of the rotor). As shown in Figure 11, the first side wall 410 of the holder 400 is thicker than the first side wall 310 of the holder 300 according to the third embodiment. In the first side wall 410 of the holder 400, the thickness (circumferential dimension) of portion 413 located radially outward (in the direction of arrow c) from the slit 411a on the side closer to the commutator 6, and axially on one side (in the direction of arrow a) from the other axial end (in the direction of arrow b) of the two slits 411a and 411b, is thinner than that of the rest of the first side wall 410. In other words, a flange 414 is formed adjacent to the thinner portion 413 of the first side wall 410. By providing the flange 414 on portion 413 of the first side wall 410 in the circumferential direction, portion 413 of the first side wall 410 can be made thinner than the rest of the first side wall 410.

[0065] The two slits 411a and 411b extend from the connection point between the first side wall 410 of the holder 400 and the third side wall 130 toward the other side in the axial direction (direction of arrow b). In the axial direction, the other end of the two slits 411a and 411b (direction of arrow b) is on one side (direction of arrow a) of the fourth side wall 140 of the holder 400.

[0066] The spring 412 is a so-called leaf spring and is positioned radially between two slits 411a and 411b. The spring 412 extends from the vicinity of the fourth side wall 140 of the holder 400 toward one side in the axial direction (direction of arrow a). As shown in Figure 10, the spring 412 comprises, in order from the other side in the axial direction (direction of arrow b), a connecting portion 412a, a portion having a larger dimension than the connecting portion 412a (hereinafter referred to as the thickened portion 412b), and an end portion 412c. This thickened portion 412b is formed between the connecting portion 412a and the end portion 412c and is the middle portion of the spring 412. As shown in Figure 11, in this embodiment, the spring 412 is on the side closer to the brush 7 than the outer surface of the first side wall 410 (the surface facing away from the brush 7).

[0067] The connecting portion 412a is the part that connects the spring 412 to the other part of the first side wall 410. The connecting portion 412a is formed in a flat plate shape that extends radially and axially. The connecting portion 412a is designed to elastically deform when the spring 412 biases the brush 7.

[0068] The thickened portion 412b is the part that contacts the brush 7. In the circumferential direction, the dimensions of the thickened portion 412b are larger than the dimensions of the connecting portion 412a. The thickened portion 412b has a protrusion 412e that projects toward the brush 7. The thickened portion 412b is located at a predetermined distance from both the inner end 100d and the outer end 100c of the holder 400 in the radial direction. Specifically, in the radial direction, the central part of the portion of the thickened portion 412b that contacts the brush 7 is located at a distance D7 from the end 100d of the holder 400 and at a distance D8 from the end 100c of the holder 400. D7 may be, for example, in the range of 1 / 4 to 3 / 4, 1 / 3 to 2 / 3, or 2 / 5 to 3 / 5 of D7 + D8 (the radial dimension of the holder 100). Furthermore, in the axial direction, the thickened portion 412b that contacts the brush 7 is positioned near the center of the holder 400. Also, in order to adjust the biasing force of the spring 412, the width of the connecting portion 412a and the width of the thickened portion 412b in the radial direction may be smaller than, the same as, or larger than the width of the slit 121 in the rotation axis direction.

[0069] The end 412c of the spring 412 is the end on one side in the axial direction (direction of arrow a). In the axial direction, the end 412c of the spring 412 is on the other side (direction of arrow b) of the third side wall 130 of the holder 400.

[0070] The force with which the spring 412 biases the brush 7 is smaller than the force with which the elastic member 8 biases the brush 7. Also, because the brush 7 is in contact with the first side wall 410, the second side wall 120, and the fourth side wall 140 of the holder 400, a force acts on the brush 7 that resists radial movement between it and the holder 400, in addition to the biasing force by the spring 412. This force resisting radial movement of the brush 7 (specifically, the radial static friction force generated between the brush 7 and the holder 400) is smaller than the force with which the elastic member 8 biases the brush 7. As a result, continuous contact between the brush 7 and the commutator 6 is ensured, even with changes in the radial dimensions of the brush 7.

[0071] According to the holder 400 of this embodiment, similar to the holder 100 of the first embodiment, the motor 1 is made quieter and easier to manufacture. In addition, by changing the thickness of the thickened portion 412b, the force with which the thickened portion 412b biases the brush 7 can be adjusted.

[0072] According to this embodiment, when designing the motor 1, the force with which the spring 412 biases the brush 7 can be adjusted by changing the length of the connecting portion 412a of the spring 412 without changing the radial position of the portion of the spring 412 that contacts the brush 7.

[0073] [Fifth Embodiment] Next, the configuration of the holder 500 of the motor 1 according to the fifth embodiment will be described with reference to Figures 12 and 13. The holder 500 corresponds to the holder 22 described above, but in this embodiment, for convenience, it will be referred to as holder 500. The holder 500 has the same configuration as the holder 100 according to the first embodiment, except that it has a first side wall 510 instead of the first side wall 110. Hereinafter, members, parts, and components that have the same function and configuration as in the first embodiment will be denoted by the same reference numerals, and their detailed descriptions may be omitted.

[0074] Figure 12 is a perspective view showing the configuration of the holder 500. In Figure 12, parts of the holder 500 (part of the second side wall 120 and part of the third side wall 130) are omitted to make parts that would otherwise be hidden by the second side wall 120 easier to see. As mentioned above, the holder 500 can be formed integrally with the bracket 2 of the motor 1, but in Figure 12, only the holder 500 is shown as an excerpt. Figure 13 shows the holder 500, brush 7, elastic member 8, conductor 9, and column 23, and is a view of the motor 1 from the outside to the inside in the radial direction (direction of arrow d in Figures 1 and 2).

[0075] The first side wall 510 is configured to bias the brush 7 in the circumferential direction of the motor 1 (the direction from the first side wall 510 toward the second side wall 120). Specifically, the first side wall 510 includes a slit 511a formed to extend in the axial direction, a slit 511b formed to extend in the radial direction, and a plate-shaped spring 512 (sometimes referred to as the "first spring" for convenience) provided adjacent to the two slits 511a and 511b, and the spring 512 biases the brush 7 in the circumferential direction of the motor 1.

[0076] Slit 511a extends from the connection point between the first side wall 510 of the holder 500 and the third side wall 130 toward the other side in the axial direction (direction of arrow b). In the axial direction, the other end of slit 511a (direction of arrow b) is on one side (direction of arrow a) of the fourth side wall 140 of the holder 500. Slit 511b extends from the first opening 150 formed in the end 100c of the holder 500 toward the radially inward direction (direction of arrow d) toward slit 511a. The radially inward end of slit 511b (direction of arrow d) is radially outward (direction of arrow c) of the second opening 160 of the holder 500. The other end of slit 511a (direction of arrow b) in the axial direction is connected to the radially inward end of slit 511b (direction of arrow d) at a predetermined angle (approximately a right angle).

[0077] The spring 512 is a so-called leaf spring. The spring 512 is the portion of the first side wall 510 that is radially outward from the slit 511a (direction of arrow c) and axially on one side of the slit 511b (direction of arrow a). The spring 512 extends from the vicinity of the third side wall 130 of the holder 500 toward the other side in the axial direction (direction of arrow b).

[0078] The spring 512 has a protrusion 512e that projects toward the brush 7 at both its radially inner end (direction of arrow d) and its axially opposite end (direction of arrow b). The protrusion 512e has a curved surface 512d facing toward the brush 7. The protrusion 512e is located at a predetermined distance from both the inner end 100d and the outer end 100c of the holder 500 in the radial direction. Specifically, in the radial direction, the portion of the protrusion 512e that contacts the brush 7 is located at a distance D9 from the end 100d of the holder 500 and at a distance D from the end 100c of the holder 500. 10 They are separated by that much. D9 is, for example, D9+D 10 The radial dimension of the holder 100 may be within the range of 1 / 4 to 3 / 4, 1 / 3 to 2 / 3, or 2 / 5 to 3 / 5. In addition, in the axial direction, the protrusion 512e is positioned near the center of the holder 500.

[0079] The force with which the spring 512 biases the brush 7 is smaller than the force with which the elastic member 8 biases the brush 7. Also, because the brush 7 is in contact with the first side wall 510, the second side wall 120, and the fourth side wall 140 of the holder 500, a force acts on the brush 7 that resists radial movement between it and the holder 500, in addition to the biasing force by the spring 512. The force resisting radial movement of the brush 7 (specifically, the radial static friction force generated between the brush 7 and the holder 500) is smaller than the force with which the elastic member 8 biases the brush 7. As a result, continuous contact between the brush 7 and the commutator 6 is ensured, even with changes in the radial dimensions of the brush 7.

[0080] According to the holder 500 of this embodiment, similar to the holder 100 of the first embodiment, the motor 1 is made quieter and easier to manufacture. In addition, by changing the thickness of the protrusion 512e, the force with which the spring 512 biases the brush 7 can be adjusted.

[0081] Although preferred embodiments of the motor of the present invention have been described above, the motor of the present invention is not limited to the configuration of the embodiments described above. Examples of other configurations that the motor of the present invention can employ are described below.

[0082] For example, in the motor of the present invention, the holder may be formed separately from the bracket. The side walls of the holder, excluding the first side wall, do not need to have slits. Also, the first side wall of the holder does not need to have slits, as long as it can bias the brush in the circumferential direction. A coil spring or the like may be placed on the first side wall of the holder instead of a plate spring.

[0083] Furthermore, those skilled in the art can modify the motor of the present invention as appropriate, and change the shape, dimensions, and combinations of various components, in accordance with conventionally known knowledge. Such modifications, if they still possess the configuration of the present invention, are naturally included within the scope of the present invention. [Explanation of Symbols]

[0084] 1...Motor, 6...Commutator, 7...Brush, 8...Elastic member (second spring), 22, 100, 200, 300, 400, 500...Holder, 110, 210, 310, 410, 510...Side wall (first side wall), 150...Opening, 111a, 111b, 211a, 211b, 311a, 311b, 411a, 411b, 511a, 511b...Slit, 112, 212, 312, 412, 512...Spring (first spring).

Claims

1. A commutator and A brush that contacts the commutator, A holder for housing the aforementioned brush, The motor comprises a holder having an opening that faces the opposite side of the commutator and a side wall that biases the brush in the circumferential direction.

2. The motor according to claim 1, wherein a slit is formed in the side wall.

3. The motor according to claim 2, wherein the side wall is provided with a plate-shaped spring adjacent to the slit.

4. The motor according to claim 3, wherein the spring has a portion that contacts the brush.

5. The motor according to claim 4, wherein the portion that contacts the brush has a protrusion that extends toward the brush.

6. The motor according to claim 4, wherein the part that contacts the brush has a curved surface.

7. The motor according to any one of claims 4 to 6, wherein the portion that contacts the brush is radially separated by a predetermined distance from either the inner end or the outer end of the holder in the radial direction.

8. Let the aforementioned spring be the first spring. The holder is equipped with a second spring that biases the brush in the radial direction. The motor according to any one of claims 3 to 7, wherein the force with which the first spring biases the brush is less than the force with which the second spring biases the brush.

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