Brush motor

Abstract

To cool the inside of a brush motor in an effective manner.SOLUTION: A brush motor includes a casing 1 having a cylindrical section, a plurality of permanent magnets 2 each having an arc transverse section and being spaced from each other in a circumferential direction s of the inner circumferential surface of the casing 1, and a rotor 3 that faces the inner circumferential surfaces 2a of the respective permanent magnets 2 and has an outer circumferential surface 3a disposed with a gap g from the inner circumferential surfaces. A plurality of slits 5 through which air in the casing 1 passes are formed in a side surface 1a of the casing 1. Each of the slits 5 extends in the circumferential direction of the casing 1.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to the cooling of a permanent magnet field DC motor.

Background Art

[0002] Conventionally, in order to suppress the temperature rise of a brush motor, air holes are formed at the bottom of a casing having a cylindrical side surface, and a structure is adopted in which air flows into the inside.

Summary of the Invention

Problems to be Solved by the Invention

[0003] However, since the inside of the motor is covered by the side surface of the casing, heat is likely to be trapped, the temperature inside the motor rises, and the durability of the motor deteriorates. However, if an opening is provided on the side surface, a part of the magnetic circuit is interrupted, so that the performance of the motor deteriorates, and there is a risk that foreign matters such as water and dust may enter the motor from the opening.

[0004] Therefore, an object of the present invention is to suppress the temperature rise of a brush motor by providing an opening on the side surface of the casing and ventilating the inside of the motor while suppressing the influence on the motor performance and the risk of foreign matter intrusion into the motor.

Means for Solving the Problems

[0005] The present invention includes a casing 1 having a cylindrical portion, a plurality of permanent magnets 2 having a cross-sectional arc shape spaced apart from each other in the circumferential direction s of the inner peripheral surface of the casing 1, a rotor 3 facing the inner peripheral surface 2a of each permanent magnet 2 and having an outer peripheral surface 3a disposed with a gap g therebetween, in a brush motor comprising: a plurality of slits 5 through which air in the casing 1 enters and exits are formed on the side surface la of the casing 1, the slits 5 extend in the circumferential direction of the casing 1 It is formed to be parallel to the flow in the magnetic circuit within the motor. and a brush motor characterized by this. [[ID=?]] [[ID=?]]

[0006] In the brush motor of the present invention, each slit 5 can be formed by a louver 5a cut out of the casing 1.

[0007] In the brush motor of the present invention, at least one of the surfaces between the multiple slits 5 may protrude either towards the inner diameter side or the outer diameter side of the cylindrical portion of the casing 1. [Effects of the Invention]

[0008] The present invention is characterized in that a plurality of slits 5 are formed on the side surface 1a of the casing 1, through which air enters and exits the casing 1, and the slits 5 extend in the circumferential direction of the casing 1. This configuration limits the disruption of the magnetic circuit to only the width of the slit, thus minimizing the impact on motor performance. Furthermore, foreign objects larger than the width of the slit cannot pass through the slit, thus preventing foreign objects from entering the motor.

[0009] The present invention further allows each slit 5 to be formed by a louver 5a cut out of the casing 1. This configuration shields the front of the slit with a louver, thus preventing foreign objects from entering the motor from the front while still providing a sufficient opening for ventilation.

[0010] The present invention further allows at least one of the surfaces between the multiple slits 5 to protrude either towards the inner or outer diameter side of the cylindrical portion of the casing 1. This configuration allows for sufficient ventilation openings while minimizing disruption of the magnetic circuit. [Brief explanation of the drawing]

[0011] [Figure 1] A perspective view of a brush motor according to the first embodiment of the present invention. [Figure 2] Front view of the same. [Figure 3]This is a cross-sectional diagram illustrating the main part, specifically a cross-sectional view taken along the line III-III in Figure 1. [Figure 4] Enlarged view of IV in Figure 3. [Figure 5] Cross-sectional view of the main part. [Figure 6] A diagram illustrating the relationship between the magnetic circuit of the brush motor and the slit. [Figure 7] A cross-sectional view showing another example of the first embodiment of the present invention. [Figure 8] A perspective view of a brush motor according to a second embodiment of the present invention. [Figure 9] This is a cross-sectional diagram illustrating the main part, specifically a cross-sectional view taken along the line IX-IX in Figure 8. [Figure 10] A perspective view showing another example of a second embodiment of the present invention. [Figure 11] This is a cross-sectional diagram illustrating the main part, specifically a cross-sectional view taken along the line XI-XI in Figure 10. [Modes for carrying out the invention]

[0012] Next, we will describe the configuration common to each embodiment based on the drawings. The explanation of the individual components within the motor, other than the inventive configuration of this brush motor, will be omitted. This brush motor comprises a casing 1, permanent magnets 2, and a rotor 3. As shown in Figure 3, the casing 1 has a cylindrical side surface 1a made of a magnetic metal such as iron, and one end is closed off by a bottom 1b. The other end of the casing 1 is closed off by an end cap 10. The bottom 1b of the casing 1 may be a separate component, such as the end cap 10. Multiple permanent magnets 2 with an arc-shaped cross-section are arranged on the inner circumferential surface of the casing 1, spaced apart from each other in the circumferential direction s (there is a spaced portion 4 between adjacent permanent magnets 2). The aforementioned side surface 1a has a side surface 1aa on which the permanent magnets 2 are arranged, and a side surface 1ab located in the spaced portion 4. In Figure 1, four permanent magnets 2 are arranged, but the number of permanent magnets 2 arranged is not limited to this example. Inside the casing 1, a rotor 3 facing the inner peripheral surface 2a of each permanent magnet 2 is arranged via a rotating shaft 9 so as to be rotatable freely. There is a gap g between the outer peripheral surface 3a of the rotor 3 and the inner peripheral surface 2a of each permanent magnet 2.

[0013] The feature of the present invention is that a plurality of slits 5 through which air in the casing 1 enters and exits are formed on the side surface 1a of the casing 1, and each slit 5 extends in the circumferential direction of the casing 1. Each slit 5 is formed at intervals in the axial direction of the rotating shaft 9.

Embodiment

[0014] Figs. 1 to 5 show a first embodiment of the present invention, Fig. 1 is a perspective view of a main part of a brush motor, Fig. 2 is a front view thereof, Fig. 3 is a longitudinal sectional view of the main part thereof and is a sectional view taken along the arrow III-III in Fig. 1, Fig. 4 is an enlarged view of Fig. 3 at IV, and Fig. 5 is a transverse sectional view of the main part of the motor. In the first embodiment, slits 5 are formed by raising louvers 5a on the side surface 1ab located in the separation part 4. As shown in Fig. 6, the slits 5 extend in the circumferential direction of the casing 1 and are formed so as to be parallel to the flow of the magnetic circuit in the motor. The direction of inclination of the louver 5a is not limited to the direction shown in Figs. 3 and 4, and may be in the opposite direction. As shown in Figs. 1 and 3, air holes 11 can be provided in the bottom 1b of the casing 1. When allowing an air flow 12 to flow through from the side surface 1a side of the motor, as shown in Fig. 7, only the slits 5 formed on the side surface 1a can be provided without forming the air holes 11.

[0015] In the first embodiment, as shown in Fig. 3, an air flow 12 flows into the motor from the air holes 11 of the casing 1. The air flow 12 that has flowed into the motor cools each component in the motor and is guided to the side of the side surface 1ab located in the separation part 4, and as shown in Fig. 4, the air flow 12 flows out to the outside from the slits 5.

[0016] As shown in Figure 6, the slit 5 is cut and bent so that its orientation in the width direction is parallel to the flow of the magnetic circuit inside the motor. Therefore, the disruption of the magnetic circuit is limited to the width of the slit 5, and the impact on the motor's performance is suppressed. Furthermore, in this embodiment, since the front of the slit 5 is shielded by the louver 5a, it is possible to obtain a slit 5 that allows sufficient ventilation while suppressing the intrusion of foreign matter into the motor from the front. [Examples]

[0017] Figure 8 is a perspective view of a brush motor according to a second embodiment of the present invention, and Figure 9 is a cross-sectional explanatory view of the main part thereof, taken along the line IX-IX in Figure 8. In the second embodiment, as shown in Figures 8 and 9, the surface between the two slits 5 protrudes inward from the side surface 1ab of the casing 1, forming a protruding surface 5b. This configuration allows for sufficient ventilation openings while minimizing disruption of the magnetic circuit. The protruding surface 5b shown in Figures 8 and 9 is projected inward from the side surface 1ab, but it can also be made to project outward from the cylinder.

[0018] As shown in Figures 10 and 11, the casing 1 can also be formed using only a number of elongated slits 5, without forming a protruding surface 5b on the side surface 1ab. [Industrial applicability]

[0019] The present invention can be used in permanent magnet field DC motors, and is particularly suitable for motors that drive fans for radiators. [Explanation of Symbols]

[0020] 1 Casing 1a side 1b bottom 1aa Side where permanent magnet 2 is located 1ab Side located at the separated portion 4 2 permanent magnets 2a Inner surface 3 rotors 3a Outer surface 4 Separation part 5 slits 5a Louver 5b Protruding surface

[0021] 9 Rotation axis 10 End cover 11 air vents 12 Airflow g gap s circumferential direction h Axial direction

Claims

[Claim 1] A casing (1) having a cylindrical portion, Multiple permanent magnets (2) with a cross-sectional arc shape are spaced apart from each other in the circumferential direction (s) of the inner surface of the casing (1), A brush motor comprising: a rotor (3) facing the inner circumferential surface (2a) of each permanent magnet (2) and having an outer circumferential surface (3a) with a gap (g) between them, Multiple slits (5) are formed on the side surface (1a) of the casing (1) through which air enters and exits the casing (1). A brush motor characterized in that the slits (5) extend in the circumferential direction of the casing (1) and are formed to be parallel to the flow of the magnetic circuit inside the motor, and at least one of the surfaces between the plurality of slits (5) protrudes to the inner or outer diameter side of the cylindrical portion of the casing (1).

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