Motor system, heat sink, and coupling

Abstract

The present invention increases heat dissipation performance. A motor system (100) is provided with a motor (1), a coupling (3), and a heat sink (2). The motor (1) has a housing (10) and a first shaft (11). The coupling (3) connects, in the axial direction of the first shaft (11) of the motor (1), the first shaft (11) and a second shaft (A2) that transmits the rotational force of the first shaft (11) to a load (A1). The heat sink (2) is attached to the side surface of the first shaft (11) between the housing (10) of the motor (1) and the coupling (3).

Description

Motor systems, heat sinks and couplings

[0001] The present disclosure relates generally to motor systems, heat sinks, and couplings, and more particularly to a motor system including a motor, a heat sink attached to the motor shaft, and a coupling attached to the motor shaft.

[0002] Patent Document 1 discloses an electric motor. The electric motor includes a motor shaft and a cover plate attached to the motor shaft. A number of heat dissipation fins are formed on the front side of the cover plate.

[0003] Japanese Patent Application Laid-Open No. 2017-153263

[0004] Incidentally, in electric motors (motors) such as that disclosed in Patent Document 1, improvements in heat dissipation performance are desired.

[0005] The present disclosure has been made in view of the above-mentioned circumstances, and aims to provide a motor system, a heat sink, and a coupling that can improve heat dissipation performance.

[0006] A motor system according to one aspect of the present disclosure includes a motor, a coupling, and a heat sink. The motor has a housing and a first shaft. The coupling connects the first shaft of the motor to a second shaft in the axial direction of the first shaft, the second shaft transmitting the rotational force of the first shaft to a load. The heat sink is attached to a side of the first shaft between the motor housing and the coupling.

[0007] A heat sink according to one aspect of the present disclosure is used as a heat sink for a motor system.

[0008] A coupling according to one aspect of the present disclosure is a coupling that connects a first shaft and a second shaft of a motor in the axial direction of the first shaft. The second shaft transmits the rotational force of the first shaft to a load. The coupling includes a base and a plurality of fins. The base is attached to the first shaft. The plurality of fins protrude radially from the base in a direction perpendicular to the axial direction.

[0009] According to the present disclosure, it is possible to improve heat dissipation performance.

[0010] FIG. 1 is a side view of a motor system according to a first embodiment. FIG. 2 is a perspective view of a main part of the motor system according to the first embodiment. FIG. 3 is an explanatory diagram for explaining measurement points of thermal analysis in the motor system according to the first embodiment. FIG. 4 is a graph showing the results of thermal analysis in the motor system according to the first embodiment. FIG. 5 is a side view of a main part of a motor system according to a second embodiment. FIG. 6 is an exploded perspective view of a coupling provided in the motor system according to the second embodiment. FIG. 7 is a perspective view of a main part of a motor system according to a third embodiment. FIG. 8 is a cross-sectional view of a main part of a motor system according to a fourth embodiment. FIG. 9 is an exploded perspective view of a main part of the motor system according to the fourth embodiment.

[0011] Preferred embodiments of the present disclosure will be described in detail below with reference to the drawings. Common elements in the embodiments described below are designated by the same reference numerals, and redundant descriptions of the common elements may be omitted. The following embodiments and modifications are merely a portion of the various embodiments of the present disclosure. Various modifications of the following embodiments and modifications may be made depending on the design, etc., as long as the object of the present disclosure can be achieved. The configurations of the embodiments and modifications may also be combined as appropriate.

[0012] The drawings described in this disclosure are schematic diagrams, and the ratios of the sizes and thicknesses of the components in the drawings do not necessarily reflect the actual dimensional ratios. Note that the arrows indicating the directions in the drawings are merely examples and are not intended to define the directions when the motor system 100 is in use. Furthermore, the arrows indicating the directions in the drawings are merely shown for the purpose of explanation and do not have any substance.

[0013] (First Embodiment) (1) Overview First, an overview of a motor system 100 according to a first embodiment will be described with reference to Fig. 1. Fig. 1 is a side view of the motor system 100 according to the first embodiment.

[0014] The motor system 100 of the first embodiment is a system that transmits the rotational force of the first shaft 11 (motor shaft) of the motor 1 to a load A1.

[0015] As shown in FIG. 1 , the motor system 100 of the first embodiment includes a motor 1 , a heat sink 2 , and a coupling 3 .

[0016] The motor 1 includes a housing 10 and a first shaft 11 .

[0017] The coupling 3 connects the first shaft 11 of the motor 1 in the axial direction of the first shaft 11 to a second shaft A2 that transmits the rotational force of the first shaft 11 to a load A1.

[0018] The heat sink 2 is attached to the side of the first shaft 11 between the housing 10 of the motor 1 and the coupling 3 .

[0019] According to the motor system 100 of embodiment 1, heat generated by the coils of the motor 1 when the motor 1 is driven can be released, for example, into the air via the first shaft 11 and the heat sink 2, thereby improving the heat dissipation performance of the motor 1.

[0020] (2) Details The detailed configuration of the motor system 100 according to the first embodiment will be described below with reference to Figures 1 and 2. Figure 2 is a perspective view of the main parts of the motor system 100 according to the first embodiment.

[0021] In the following description, the direction parallel to the axial direction of the first shaft 11 of the motor 1 is defined as the front-rear direction. The direction from the housing 10 of the motor 1 toward the coupling 3 is defined as the forward direction, and the direction from the coupling 3 toward the housing 10 is defined as the rearward direction. The direction in which the base 4 (see FIG. 1) and the housing 10 of the motor 1 are aligned is defined as the up-down direction. The direction from the housing 10 of the motor 1 toward the base 4 is defined as the downward direction, and the direction from the base 4 toward the housing 10 is defined as the upward direction. In this disclosure, the up-down direction is parallel to the vertical direction and perpendicular to the front-rear direction.

[0022] In addition, the term "orthogonal (perpendicular)" as used herein does not only refer to a state in which the angle between two things is exactly 90 degrees, but also includes a state in which two things intersect within a certain range of difference. In other words, the angle between two orthogonal things falls within a certain range of difference from 90 degrees (for example, 5 degrees or less). In other words, the term "orthogonal" as used herein includes a case in which the angle between two things is 85 degrees or more and 95 degrees or less. Similarly, the term "parallel" as used herein does not only refer to a state in which two things do not strictly intersect, but also includes a state in which two things are lined up within a certain range of difference. For example, the term "parallel" as used herein includes a state in which one thing is inclined at an angle of 5 degrees or less relative to the other. In other words, the term "parallel" as used herein includes a case in which the angle between one thing and the other is -5 degrees or more and 5 degrees or less.

[0023] The load A1 in the first embodiment is disposed in front of the coupling 3. The load A1 is driven by a rotational force transmitted from the first shaft 11 of the motor 1. The load A1 is an industrial machine such as a transport machine or a machine tool, or a robot. A second shaft A2 is connected to the load A1. The rotational force is transmitted from the first shaft 11 to the second shaft A2 via the coupling 3.

[0024] As described above, the motor system 100 is a system that transmits the rotational force of the first shaft 11 of the motor 1 to the load A1 via the second shaft A2.

[0025] As shown in FIG. 1 , the motor system 100 includes a motor 1 , a heat sink 2 , a coupling 3 , a base 4 , and a mounting plate 5 .

[0026] The base 4 functions as a foundation for the motor system 100. The base 4 has a flat plate shape. The thickness direction of the base 4 is aligned with the up-down direction. The base 4 is made of, for example, metal.

[0027] The mounting plate 5 is disposed so as to protrude upward from the base 4. The mounting plate 5 is a plate on which the motor 1 is attached. The mounting plate 5 is shaped like a flat plate. The thickness direction of the mounting plate 5 is along the front-rear direction. The mounting plate 5 is formed from, for example, metal. The mounting plate 5 and the base 4 may be formed integrally or separately.

[0028] The mounting plate 5 has a through-hole 53 that penetrates the mounting plate 5 in the thickness direction. At least the first shaft 11 of the motor 1 is passed through the through-hole 53. In the first embodiment, the motor 1 is mounted to the mounting plate 5 such that the protrusion 102 of the motor 1 (see FIG. 2 ) fits into the through-hole 53.

[0029] The motor 1 is, for example, a rotary servo motor. The motor 1 includes a housing 10 that houses a coil, a stator, a rotor, etc., and a first shaft 11 that protrudes forward from inside the housing 10. The first shaft 11 protrudes forward from the rotor. For example, the first shaft 11 rotates when power is supplied to the motor 1 from a control device.

[0030] The motor 1 of the first embodiment is attached to the mounting plate 5 with a protrusion 102 provided on the front surface 101 of the housing 10 (see FIG. 2 ) fitted into the through-hole 53 of the mounting plate 5. The protrusion 102 is circular in a plan view from the front-to-rear direction and protrudes forward from the front surface 101. A through-hole through which the first shaft 11 passes is formed in the center of the front surface 101 and the protrusion 102. In other words, the first shaft 11 passes through the through-holes of the front surface 101 and the protrusion 102 and protrudes forward from inside the housing 10. In the first embodiment, when the motor 1 is attached to the mounting plate 5, the front surface 101 of the housing 10 and the rear surface of the mounting plate 5 are flush with each other. Furthermore, when the motor 1 is attached to the mounting plate 5, the first shaft 11 passes through the through-hole of the mounting plate 5.

[0031] The coupling 3 is attached to the side surface of the tip (i.e., the front end) of the first shaft 11 of the motor 1. More specifically, as shown in Fig. 2, the coupling 3 of the first embodiment is an Oldham coupling.

[0032] The coupling 3 includes a first hub 31, an intermediate member 32, and a second hub 33. The first hub 31 is formed of a metal such as aluminum. The first hub 31 is cylindrical with a hollow portion. The first hub 31 is attached to the side of the tip of the first shaft 11, with the tip of the first shaft 11 inserted into the hollow portion. The intermediate member 32 is disposed between the first hub 31 and the second hub 33 in the front-rear direction. The intermediate member 32 is formed of a synthetic resin such as POM (Poly Oxy Methylene) resin, which has relatively high slidability and high wear resistance. However, the intermediate member 32 may also be formed of a metal such as aluminum. The intermediate member 32 transmits rotational force between the first hub 31 and the second hub 33. The second hub 33 is formed of a metal such as aluminum. The second hub 33 is cylindrical with a hollow portion. The second hub 33 is attached to the side of the tip (rear end) of the second shaft A2 with the tip (rear end) of the second shaft A2 inserted into the hollow portion.

[0033] In the motor system 100 of the first embodiment, by providing the coupling 3, which is an Oldham coupling, it is possible to reduce the precision required for centering between the first shaft 11 and the second shaft A2.

[0034] As described above, the heat sink 2 is attached to the side surface of the first shaft 11 between the housing 10 of the motor 1 and the coupling 3. The heat sink 2 has a base 20 and a plurality of fins 23 (14 in the example of FIG. 2 ).

[0035] The base 20 is made of a metal such as aluminum. The base 20 has a cylindrical shape with a hollow portion. The base 20 is attached to the side of the first shaft 11 with the first shaft 11 passing through the hollow portion.

[0036] The fins 23 are formed of a metal such as aluminum. The fins 23 protrude radially from the front side of the outer circumferential surface of the base 20 along a direction perpendicular to the axial direction of the first shaft 11. In other words, the fins 23 protrude radially from the front side of the outer circumferential surface of the base 20 along the radial direction of the base 20. More specifically, the fins 23 are arranged at equal intervals along the circumferential direction of the outer circumferential surface of the base 20. Each of the fins 23 has a triangular prism shape. In the first embodiment, the fins 23 are located forward of the front surface 51 of the mounting plate 5. More specifically, the rear ends of the fins 23 are located forward of the front surface 51 of the mounting plate 5.

[0037] According to the motor system 100 of the first embodiment, the heat sink 2 having the plurality of fins 23 is attached to the first shaft 11 of the motor 1, thereby further improving the heat dissipation performance of the motor 1. Furthermore, the plurality of fins 23 of the first embodiment are formed from a metal with relatively high thermal conductivity, thereby further improving the heat dissipation performance of the motor 1.

[0038] The heat sink 2 of the first embodiment is configured to be separable. More specifically, the base 20 of the heat sink 2 is configured to be separable into two equal parts along the radial direction of the base 20. In other words, the heat sink 2 has a first portion 21 and a second portion 22.

[0039] The first portion 21 has a first base 210 and a plurality of (seven in the example of FIG. 2 ) fins 23. The first base 210 has a semi-cylindrical shape. The first base 210, together with a second base 220 (described later), constitutes the base 20 of the heat sink 2.

[0040] The second portion 22 has a second base 220 and a plurality of (seven in the example of FIG. 2 ) fins 23. The second base 220 has a semi-cylindrical shape. The second base 220, together with the first base 210, constitutes the base 20 of the heat sink 2.

[0041] The heat sink 2 of the first embodiment is configured to be detachable from the first shaft 11 of the motor 1. When attaching the heat sink 2 to the first shaft 11, for example, an operator clamps the sides of the first shaft 11 between the first portion 21 and the second portion 22 and fastens the first portion 21 and the second portion 22 to each other with fastening members such as bolts, thereby attaching the heat sink 2 to the first shaft 11. When removing the heat sink 2 from the first shaft 11, for example, an operator removes the fastening members fastening the first portion 21 and the second portion 22 to each other, separates the heat sink 2 into the first portion 21 and the second portion 22, and then removes the heat sink 2 from the first shaft 11. As a result, if the temperature of the motor 1 is within the allowable temperature range due to environmental conditions, driving conditions of the motor 1, or the like, removing the heat sink 2 from the first shaft 11 can reduce the load on the motor 1. In other words, when the heat sink 2 is not required, the load on the motor 1 can be reduced by removing the heat sink 2 from the first shaft 11 .

[0042] (3) Effects The applicant has conducted a thermal analysis to verify the effects of the motor system 100 of embodiment 1. More specifically, the applicant has selected seven measurement points, namely, the first measurement point to the seventh measurement point, and conducted a thermal analysis.

[0043] FIG. 3 is an explanatory diagram illustrating measurement points for thermal analysis in the motor system 100 according to the first embodiment. The first measurement point is a coil disposed within the housing 10 of the motor 1. As shown in FIG. 3, the second measurement point is measurement point P2 on the rear surface 52 of the mounting plate 5. The third measurement point is measurement point P3 on the side surface of the housing 10. The fourth measurement point is measurement point P4 on the side surface of the housing 10. The fifth measurement point is measurement point P5 on the side surface of the housing 10. The sixth measurement point is measurement point P6 on the side surface of the housing 10. The seventh measurement point is measurement point P7 on the side surface of the housing 10. Measurement point P2, measurement point P3, measurement point P4, measurement point P5, measurement point P6, and measurement point P7 are arranged in this order from the front: measurement point P2, measurement point P3, measurement point P4, measurement point P5, measurement point P6, and measurement point P7.

[0044] Fig. 4 is a graph showing the results of thermal analysis of the motor system 100 according to embodiment 1. The solid line graph in Fig. 4 shows the results of thermal analysis of the motor system not including the heat sink 2. The dashed line graph in Fig. 4 shows the results of thermal analysis of the motor system 100 according to embodiment 1. The motor system not including the heat sink 2 is a system in which the heat sink 2 is removed from the first shaft 11 of the motor system 100 described above.

[0045] In the thermal analysis, by attaching the heat sink 2 to the first shaft 11, the temperature decreased by 9.85 K at the first measurement location, 10.31 K at the second measurement location, 9.92 K at the third measurement location, 9.80 K at the fourth measurement location, 9.77 K at the fifth measurement location, 9.71 K at the sixth measurement location, and 9.73 K at the seventh measurement location. In other words, the thermal analysis confirmed that by attaching the heat sink 2 to the first shaft 11 of the motor 1, the heat dissipation performance of the motor 1 is improved.

[0046] (4) Modifications Modifications of the first embodiment are listed below.

[0047] In the first embodiment, the coupling 3 is an Oldham type coupling. However, the coupling 3 may be another type of coupling such as a disk type or a slit type.

[0048] In the first embodiment, the heat sink 2 has been described as having a configuration in which the multiple fins 23 protrude radially from the base 20 in a direction perpendicular to the axial direction of the first shaft 11. However, the heat sink 2 may have other configurations. For example, the base 20 may be disk-shaped with a hollow portion, and the multiple fins 23 may protrude forward from the front surface of the base 20. Alternatively, the base 20 may be disk-shaped with a hollow portion, and the multiple fins 23 may protrude rearward from the rear surface of the base 20.

[0049] In the first embodiment, the base 20 of the heat sink 2 is configured to be separable. However, it is not essential that the base 20 of the heat sink 2 be configured to be separable. Furthermore, the heat sink 2 may be attached to the side of the first shaft 11 of the motor 1 by passing the first shaft 11 through the hollow portion of the base 20.

[0050] The heat sink 2 used in the motor system 100 may be distributed independently on the market. Also, the coupling 3 used in the motor system 100 may be distributed independently on the market.

[0051] Second Embodiment A motor system 100 according to a second embodiment will be described with reference to FIGS. 5 and 6. FIG.

[0052] 5 is a side view of a main part of a motor system according to embodiment 2. In the motor system 100 of embodiment 2, the heat sink 2 and the coupling 3 are integrally formed. In other words, the coupling 3 of embodiment 2 functions as the heat sink 2.

[0053] Similar to the coupling 3 of the first embodiment, the coupling 3 of the second embodiment connects the first shaft 11 of the motor 1 to the second shaft A2 in the axial direction of the first shaft 11, which transmits the rotational force of the first shaft 11 to the load A1.

[0054] As shown in Fig. 6, the coupling 3 of the second embodiment is an Oldham coupling, similar to the coupling 3 of the first embodiment. The coupling 3 includes a first hub 31, an intermediate member 32, and a second hub 33. The intermediate member 32 and the second hub 33 of the second embodiment are similar to the intermediate member 32 and the second hub 33 of the first embodiment.

[0055] 6 is an exploded perspective view of the coupling 3 included in the motor system 100 according to the second embodiment. The first hub 31 of the second embodiment has a base 310 and a plurality of fins 23. In other words, the coupling 3 has the base 310 and a plurality of fins 23. The base 310 is formed of a metal such as aluminum. The base 310 has a cylindrical shape with a hollow portion. The base 310 is attached to the side of the first shaft 11 with the first shaft 11 passing through the hollow portion. The base 310 functions as the base 20 of the heat sink 2.

[0056] The multiple fins 23 are made of metal such as aluminum. The multiple fins 23 protrude radially from the front side of the outer circumferential surface of the base 310 along a direction perpendicular to the axial direction of the first shaft 11. In other words, the multiple fins 23 protrude radially from the front side of the outer circumferential surface of the base 310 along the radial direction of the base 310. More specifically, the multiple fins 23 are arranged at equal intervals along the circumferential direction of the outer circumferential surface of the base 310. Each of the multiple fins 23 has a triangular prism shape.

[0057] According to the motor system 100 of the second embodiment, the heat sink 2 and the coupling 3 are integrally formed, which allows for a lighter weight and a reduced load on the motor 1 compared to when the heat sink 2 and the coupling 3 are separate components. Also, the coupling 3 (heat sink 2) having the multiple fins 23 is attached to the first shaft 11 of the motor 1, which further improves the heat dissipation performance of the motor 1. Furthermore, the multiple fins 23 of the second embodiment are formed from a metal with relatively high thermal conductivity, which further improves the heat dissipation performance of the motor 1.

[0058] Third Embodiment A motor system 100 according to a third embodiment will be described with reference to FIG.

[0059] FIG. 7 is a perspective view of a main portion of a motor system 100 according to a third embodiment. The motor system 100 of the third embodiment further includes a protective cover 6. As shown in FIG. 7 , the protective cover 6 is disposed so as to cover the heat sink 2. The protective cover 6 is formed of metal. The protective cover 6 of the third embodiment is attached to the mounting plate 5 by fastening members such as bolts. The protective cover 6 is attached to the mounting plate 5 so as to be in mechanical contact with the mounting plate 5. In other words, the protective cover 6 is thermally connected to the mounting plate 5. This allows a portion of the heat transferred from the housing 10 of the motor 1 to the mounting plate 5 to be dissipated via the protective cover 6, thereby further improving the heat dissipation performance of the motor 1.

[0060] (Embodiment 4) A motor system 100 according to embodiment 4 will be described with reference to Fig. 8 and Fig. 9. Fig. 8 is a cross-sectional view of a main part of the motor system 100 according to embodiment 4. Fig. 9 is an exploded perspective view of a main part of the motor system 100 according to embodiment 4.

[0061] The motor system 100 of the fourth embodiment further includes a first member 7 , a second member 8 , and a bearing 9 .

[0062] The protective cover 6 of the fourth embodiment is attached to the mounting plate 5 by fitting the outer circumferential surface of the cylindrical protrusion 61 into the through-hole 53 of the mounting plate 5 .

[0063] The bearing 9 is, for example, a ball bearing. The bearing 9 is disposed inside the protrusion 61 of the protective cover 6. The outer peripheral surface of the bearing 9 fits into the inner peripheral surface of the protrusion 61 of the protective cover 6, so that the bearing 9 is supported by the protective cover 6. In other words, the bearing 9 fits into the through-hole 53 of the mounting plate 5 via the protrusion 61 of the protective cover 6.

[0064] The first shaft 11 of the fourth embodiment has a first portion 111, a second portion 112, and a third portion 113. The first portion 111, the second portion 112, and the third portion 113 are continuous in the axial direction of the first shaft 11. The first portion 111 is a portion corresponding to the tip (front end) of the first shaft 11. The first portion 111 is cylindrical in shape. The first portion 111 is a portion inserted into the hollow portion of the coupling 3. The second portion 112 is continuous with the first portion 111 and the third portion 113 and is a portion rearward of the first portion 111 and forward of the third portion 113. The second portion 112 is cylindrical in shape. The first member 7, the second member 8, and the heat sink 2 are attached to the side surface of the second portion 112 of the first shaft 11. Here, the heat sink 2 is attached to the side surface of the second portion 112 of the first shaft 11 via the second member 8. The third portion 113 is continuous with the second portion 112 and is a rear portion of the second portion 112. The third portion 113 has a cylindrical shape. Here, the diameter of the second portion 112 is smaller than the diameter of the first portion 111 and the diameter of the third portion 113.

[0065] The first member 7 is attached to the side surface of the second portion 112 of the first shaft 11. The first member 7 is attached to the tip (front end) portion of the second portion 112. The first member 7 has an annular shape. The first member 7 includes a first plate portion 71, a second plate portion 72, and multiple connecting portions 73. The first plate portion 71 and the second plate portion 72 have the same annular plate shape. The first plate portion 71 is located in front of the second plate portion 72. The first plate portion 71 and the second plate portion 72 are formed of a metal such as aluminum. The multiple connecting portions 73 connect the first plate portion 71 and the second plate portion 72. The multiple connecting portions 73 are shaped like rectangular plates. The multiple connecting portions 73 protrude obliquely from the rear surface of the first plate portion 71 toward the front surface of the second plate portion 72 in the front-rear direction (axial direction of the first shaft 11) and the up-down direction.

[0066] The multiple connecting portions 73 are formed of a bimetal made by bonding together two types of metal plates with different thermal expansion coefficients. The multiple connecting portions 73 deform more along the axial direction of the first shaft 11 as the temperature increases within a predetermined temperature range. As a result, the length of the first member 7 along the axial direction of the first shaft 11 increases as the temperature increases within the predetermined temperature range.

[0067] In other words, the first member 7 changes from the first state to the second state when the temperature of the first member 7 changes from the first temperature to a second temperature that is higher than the first temperature. Here, for example, the first temperature and the second temperature are temperatures within a predetermined temperature range. The length of the first member 7 along the axial direction of the first shaft 11 is longer when the first member 7 is in the second state than when the first member 7 is in the first state.

[0068] The second member 8 is attached to the side surface of the second portion 112 of the first shaft 11 so as to be adjacent to the first member 7 along the axial direction of the first shaft 11. The second member 8 is disposed rearward of the first member 7. In the fourth embodiment, the second member 8 is disposed so that the front end of the second member 8 contacts the rear surface of the second plate portion 72 of the first member 7. The shape of the second member 8 is a tapered cylinder that tapers toward the rear end. In other words, the outer circumferential surface 81 of the second member 8 is a tapered surface in which the second member 8 tapers toward the rear end.

[0069] When the first member 7 changes from the first state to the second state, the second member 8 is pushed by the first member 7 and displaced from the first position to the second position. In the fourth embodiment, when the second member 8 is located in the second position, the rear end of the second member 8 is flush with the front end of the third portion 113 of the first shaft 11 and the rear surface of the base 20 of the heat sink 2.

[0070] The heat sink 2 of the fourth embodiment is rotatably supported by the bearing 9 by fitting the rear side of the outer peripheral surface of the base 20 into the inner peripheral surface of the bearing 9 .

[0071] The heat sink 2 of the fourth embodiment is attached to the side surface of the first shaft 11 via the second member 8. The inner circumferential surface 24 of the base portion 20 of the fourth embodiment is a tapered surface in which the diameter of the hollow portion increases as it approaches the front end.

[0072] The inner peripheral surface 24 of the base 20 corresponds to the outer peripheral surface 81 of the second member 8. For example, the taper angle of the inner peripheral surface 24 of the base 20 and the taper angle of the outer peripheral surface 81 of the second member 8 are approximately equal. When the second member 8 is located in the second position, the inner peripheral surface 24 of the base 20 and the outer peripheral surface 81 of the second member 8 fit together.

[0073] That is, when the second member 8 is in the second position, the heat sink 2 of the fourth embodiment rotates integrally with the first shaft 11 to follow the first shaft 11. On the other hand, when the second member 8 is in the first position, the heat sink 2 does not rotate to follow the first shaft 11. In other words, when the second member 8 is in the first position, the first shaft 11 rotates freely relative to the heat sink 2.

[0074] According to the motor system 100 of the fourth embodiment, when the temperature of the second member 8 rises above a predetermined level, the heat sink 2 rotates to follow the first shaft 11. As a result, the heat sink 2 rotates only when the heat generated by the motor 1 is relatively large, and the load on the motor 1 can be reduced when the temperature of the motor 1 is within the allowable temperature range, for example.

[0075] (Aspects) As is clear from the above-described embodiments and modifications, a motor system (100) according to a first aspect includes a motor (1), a coupling (3), and a heat sink (2). The motor (1) has a housing (10) and a first shaft (11). The coupling (3) connects the first shaft (11) of the motor (1) to a second shaft (A2) that transmits the rotational force of the first shaft (11) to a load (A1) in the axial direction of the first shaft (11). The heat sink (2) is attached to a side surface of the first shaft (11) between the housing (10) of the motor (1) and the coupling (3).

[0076] According to this aspect, the heat dissipation performance of the motor (1) can be improved.

[0077] In the motor system (100) according to the second aspect, the heat sink (2) and the coupling (3) are integrally formed in the first aspect.

[0078] According to this aspect, the load on the motor (1) can be reduced.

[0079] The motor system (100) according to a third aspect is the same as that of the first aspect, but further includes a first member (7) and a second member (8). The first member (7) is attached to a side surface of the first shaft (11). The first member (7) changes from a first state to a second state when the first temperature changes from a first temperature to a second temperature higher than the first temperature. The length of the first member (7) along the axial direction of the first shaft (11) is longer when the first member (7) is in the second state than when the first member (7) is in the first state. The second member (8) is attached to a side surface of the first shaft (11) so as to be adjacent to the first member (7) along the axial direction of the first shaft (11). When the first member (7) changes from the first state to the second state, the second member (8) is pushed by the first member (7) and displaced from the first position to the second position. The heat sink (2) is attached to the side of the first shaft (11) via a second member (8). When the second member (8) is in the second position, the heat sink (2) rotates integrally with the first shaft (11) to follow the first shaft (11), but when the second member (8) is in the first position, the heat sink (2) does not rotate with the first shaft (11).

[0080] According to this aspect, when the temperature of the motor (1) is within the allowable temperature margin, the load on the motor (1) can be reduced.

[0081] In the motor system (100) according to the fourth aspect, in the first or third aspect, the heat sink (2) is configured to be detachable from the first shaft (11).

[0082] According to this aspect, for example, when the heat sink (2) is not required, the load on the motor (1) can be reduced by removing the heat sink (2) from the first shaft (11).

[0083] In a motor system (100) according to a fifth aspect, in any one of the first to fourth aspects, the heat sink (2) has a base (20) and a plurality of fins (23). The base (20) is attached to a side surface of the first shaft (11). The plurality of fins (23) protrude radially from the base (20) in a direction perpendicular to the axial direction of the first shaft (11).

[0084] According to this aspect, the heat dissipation performance of the motor (1) can be further improved.

[0085] In the motor system (100) according to the sixth aspect, in the fifth aspect, the plurality of fins (23) are formed of metal.

[0086] According to this aspect, the heat dissipation performance of the motor (1) can be further improved.

[0087] The motor system (100) according to a seventh aspect is the motor system (100) according to any one of the first to sixth aspects, further comprising a protective cover (6). The protective cover (6) is arranged to cover the heat sink (2).

[0088] In the motor system (100) according to the eighth aspect, in the seventh aspect, the protective cover (6) is formed of metal.

[0089] According to this aspect, the heat dissipation performance of the motor (1) can be further improved.

[0090] The configurations other than the first aspect are not essential for the motor system (100) and can be omitted as appropriate.

[0091] The heat sink (2) according to the ninth aspect is used as the heat sink (2) according to the motor system (100) according to any one of the first to eighth aspects.

[0092] According to this aspect, the heat dissipation performance of the motor (1) can be improved.

[0093] A coupling (3) according to a tenth aspect is a coupling (3) that connects a first shaft (11) and a second shaft (A2) of a motor (1) in the axial direction of the first shaft (11). The second shaft (A2) transmits the rotational force of the first shaft (11) to a load (A1). The coupling (3) includes a base (20) and a plurality of fins (23). The base (20) is attached to the first shaft (11). The plurality of fins (23) radially protrude from the base (20) in a direction perpendicular to the axial direction of the first shaft (11).

[0094] According to this aspect, the heat dissipation performance of the motor (1) can be improved.

[0095] A coupling (3) according to an eleventh aspect is the same as that of the tenth aspect, and includes a first hub (31), a second hub (33), and an intermediate member (32). The first hub (31) is attached to the first shaft (11). The second hub (33) is attached to the second shaft (A2). The intermediate member (32) transmits rotational force between the first hub (31) and the second hub (33). The first hub (31) has a base (20) and a plurality of fins (23).

[0096] According to this aspect, the precision required for centering between the first shaft (11) and the second shaft (A2) can be reduced.

[0097] The motor system, heat sink, and coupling of the present disclosure can improve the heat dissipation performance of the motor, and are thus industrially useful.

[0098] REFERENCE SIGNS 100 Motor system 1 Motor 10 Housing 11 First shaft 2 Heat sink 20, 310 Base 210 First base 220 Second base 23 Fin 3 Coupling 31 First hub 32 Intermediate member 33 Second hub 6 Protective cover 7 First member 8 Second member A1 Load A2 Second shaft

Claims

1. A motor system comprising: a motor having a housing and a first shaft; a coupling that connects the first shaft of the motor to a second shaft in the axial direction of the first shaft, the second shaft transmitting the rotational force of the first shaft to a load; and a heat sink that is attached to a side of the first shaft between the housing of the motor and the coupling.

2. The motor system according to claim 1, wherein the heat sink and the coupling are integrally formed.

3. The motor system of claim 1, further comprising: a first member attached to the side surface of the first shaft, which changes from a first state to a second state when the temperature rises from a first temperature to a second temperature higher than the first temperature, and which has a length along the axial direction in the second state longer than the length along the axial direction in the first state; and a second member attached to the side surface of the first shaft so as to be adjacent to the first member along the axial direction, and which is pushed by the first member to be displaced from a first position to a second position when the first member changes from the first state to the second state, wherein the heat sink is attached to the side surface of the first shaft via the second member, and rotates integrally with the first shaft when the second member is at the second position, and does not rotate along the first shaft when the second member is at the first position.

4. The motor system according to claim 1, wherein the heat sink is configured to be detachable from the first shaft.

5. The motor system according to claim 1, wherein the heat sink has: a base attached to the side surface of the first shaft; and a plurality of fins protruding radially from the base along a direction perpendicular to the axial direction.

6. The motor system according to claim 5, wherein the plurality of fins are formed of metal.

7. The motor system according to claim 1, further comprising a protective cover disposed over the heat sink.

8. The motor system according to claim 7, wherein the protective cover is made of metal.

9. A heat sink used as the heat sink of the motor system according to claim 1.

10. A coupling that connects a first shaft of a motor to a second shaft that transmits the rotational force of the first shaft to a load in the axial direction of the first shaft, the coupling comprising: a base attached to the first shaft; and a plurality of fins that protrude radially from the base in a direction perpendicular to the axial direction.

11. The coupling according to claim 10, comprising: a first hub attached to the first shaft; a second hub attached to the second shaft; and an intermediate member that transmits the rotational force between the first hub and the second hub, wherein the first hub has the base and the plurality of fins.

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