Lead wire holding structure and motor

Abstract

A lead wire holding structure (20) is provided with: a cover (21) in which a first through-hole (22) is formed; a first fixing member (23) that is attached to the cover (21) and has a second through-hole (24); a lead wire (32) that is inserted into the first through-hole (22) and the second through-hole (24) and that has an insulating elastic body (34) that covers a conductive wire (33) and a conductive wire (33); and a packing (35) that is provided between the cover (21) and the first fixing member (23) and contacts the lead wire (32). The first fixing member (23) has at least one first protrusion (26) that is provided on the inner peripheral wall of the second through-hole (24) and that is for pressing the elastic body (34).

Description

Lead wire holding structure and motor

[0001] The present disclosure relates to a lead wire holding structure and a motor.

[0002] A technique for fastening a lead wire (or cable) by passing it through a through hole in a motor housing has been known (for example, see Patent Document 1). Patent Document 1 discloses a waterproof motor-equipped reducer having a through hole drilled in the motor housing for passing the cable therethrough, and a sealed structure for preventing water from entering the motor housing through a gap between the through hole and the cable, the through hole having a parallel shape with the same diameter on the outside and inside of the motor housing, an elastic bracket surrounding the cable and inserted into the through hole having a flange that contacts the outer surface of the motor housing, a portion of the elastic bracket that is inserted into the through hole having a conical shape with a diameter that decreases toward the inside of the motor housing, and a cable fixing plate through which the cable is passed and that presses the flange of the elastic bracket against the outer surface of the motor housing.

[0003] Japanese Patent Application Laid-Open No. 2009-33857

[0004] However, if an external force (e.g., a pulling force outward) acts on the lead wire, the lead wire may become detached from the motor housing or the connection between the lead wire and the internal circuit may be damaged. Such situations can be avoided by firmly holding the lead wire in the motor housing. However, it is undesirable to take measures that increase costs, such as increasing the number of parts, in order to achieve this. In light of these circumstances, one of the objectives of the present disclosure is to easily and firmly hold the lead wire.

[0005] One aspect of the present disclosure relates to a lead wire holding structure. The lead wire holding structure includes a cover having a first through hole formed therein, a first fixing member attached to the cover and having a second through hole, a lead wire inserted through the first through hole and the second through hole and having an insulating elastic body covering the lead wire, and a packing provided between the cover and the first fixing member and in contact with the lead wire. The first fixing member has at least one first protrusion provided on an inner circumferential wall of the second through hole and pressing against the elastic body.

[0006] Another aspect of the present disclosure relates to a motor, the motor including the lead wire holding structure described above.

[0007] According to the present disclosure, lead wires can be easily and firmly held.

[0008] FIG. 1 is a front view schematically showing a motor of embodiment 1, with a circle X surrounding a main portion of the lead wire holding structure. FIG. 2 is a front cross-sectional view schematically showing a main portion of the lead wire holding structure of embodiment 1. FIG. 3A is a plan view schematically showing a first fixing member. FIG. 3B is a front cross-sectional view schematically showing the first fixing member, taken along line III-III. FIG. 4A is a plan view schematically showing a second fixing member. FIG. 4B is a front cross-sectional view schematically showing the second fixing member, taken along line IV-IV. FIG. 5 is a front cross-sectional view schematically showing a main portion of the lead wire holding structure of embodiment 2.

[0009] The following describes examples of embodiments of the lead wire holding structure and motor according to the present disclosure. However, the present disclosure is not limited to the examples described below. While the following description may use specific numerical values ​​and materials, other numerical values ​​and materials may be used as long as the effects of the present disclosure are obtained, and various modifications are possible depending on the design, etc.

[0010] (Lead Wire Retention Structure) A lead wire retention structure according to the present disclosure is a structure for retaining lead wires in a motor cover, and includes a cover, a first fixing member, lead wires, and a packing.

[0011] The cover has a first through hole formed therein. The cover may be, for example, an encoder cover for covering an encoder for the motor. The cover may be made of, for example, an insulating resin. The shape of the first through hole is not particularly limited and may be, for example, circular.

[0012] The first fixing member is attached to the cover. The first fixing member has a second through hole. When the first fixing member is attached to the cover, the second through hole may overlap the first through hole in the axial direction. The first fixing member may be made of, for example, an insulating resin. The shape of the second through hole is not particularly limited and may be, for example, circular.

[0013] The lead wire is inserted through the first through hole and the second through hole. The lead wire has a conductive wire and an insulating elastic body (or an elastic coating) covering the conductive wire. The conductive wire may be made of, for example, copper or a copper alloy. The elastic body may be made of, for example, rubber.

[0014] The packing is provided between the cover and the first fixing member. The packing contacts the lead wire. This packing can provide a waterproof function to the lead wire holding structure according to the present disclosure. The packing may contact the elastic body of the lead wire (particularly, the outer circumferential surface of the elastic body).

[0015] The first fixing member has a first protrusion provided on the inner peripheral wall of the second through hole and pressing against the elastic body of the lead wire. Such a first protrusion presses the lead wire inside the second through hole, making it less likely for the lead wire to become detached even when an external force acts on the lead wire. Furthermore, since providing the first protrusion on the first fixing member is sufficient, there is no need to increase the number of components, and strong retention of the lead wire can be easily achieved. The first protrusion may protrude radially inward from the inner peripheral wall of the second through hole. The number of first protrusions is not particularly limited and may be, for example, one or more and four or less. When multiple first protrusions are provided, the multiple first protrusions may be arranged offset from each other in the radial and / or circumferential directions of the second through hole. The first protrusion may be integrally formed with the first fixing member.

[0016] The lead wire holding structure may further include a second fixing member provided on the side of the first fixing member opposite the side attached to the cover and having a third through hole through which the lead wire is inserted. The second fixing member may have a second protrusion provided on the inner circumferential wall of the third through hole and pressing the elastic body. The second protrusion may protrude from the inner circumferential wall of the third through hole radially inward of the third through hole. A second fixing member having such a second protrusion presses the lead wire even inside the third through hole, thereby more firmly holding the lead wire. The number of second protrusions is not particularly limited and may be, for example, one or more and four or less. When multiple second protrusions are provided, the multiple second protrusions may be arranged offset from each other in the radial and / or circumferential directions of the third through hole. The second protrusions may be integrally formed with the second fixing member.

[0017] The first and second protrusions may press the elastic body in opposite directions in the radial direction of the second and third through holes. In this configuration, the lead wires can be held more firmly by the first and second protrusions. In this case, it is preferable that the first and second protrusions are spaced apart from each other in the axial direction of the second and third through holes.

[0018] The first protrusion and the second protrusion may be spaced apart from each other in the axial direction of the second through hole and the third through hole. In this case, the lead wire is pressed by the first protrusion or the second protrusion at multiple locations aligned in the axial direction. This allows the lead wire to be held even more firmly. Note that the distance between the first protrusion and the second protrusion in the axial direction of each through hole is preferably 0.58D or more and 0.65D or less, where D is the diameter of the lead wire (or the outer diameter of the elastic body).

[0019] The first protrusion may include a first first protrusion and a second first protrusion. This allows the lead wire to be held more firmly than when there is only one first protrusion. In this case, it is not necessary to provide a second fixing member having a second protrusion.

[0020] The first first protrusion and the second first protrusion may press the elastic body in opposite directions in the radial direction of the second through hole. In this configuration, the two first protrusions can hold the lead wire more firmly. In this case, it is preferable that the two first protrusions are spaced apart from each other in the axial direction of the second through hole.

[0021] The first first protrusion and the second first protrusion may be spaced apart from each other in the axial direction of the second through hole. In this case, the lead wire is pressed by the two first protrusions at multiple positions aligned in the axial direction. This allows the lead wire to be held even more firmly. Note that the distance between the two first protrusions in the axial direction of the second through hole is preferably 0.58D or more and 0.65D or less, where D is the diameter of the lead wire (or the outer diameter of the elastic body).

[0022] The first protrusion may extend in the circumferential direction of the second through hole and be concave toward the radially outward direction of the second through hole. The concave portion of the first protrusion may be curved. In this case, the first protrusion may be arch-shaped or crescent-shaped. By pressing the lead wire with such a first protrusion, it becomes easy to align the lead wire with the center of the second through hole. Furthermore, it is possible to disperse stress generated in the lead wire by the pressing. At least one first protrusion may extend in the circumferential direction of the second through hole over a range of 122.1° or more and 138.6° or less.

[0023] The deformation (or depression) of the elastic body caused by the first protrusion may be greater than the thickness of the elastic body. In this case, assuming that the lead wire extends linearly before being pressed by the first protrusion, the tip of the first protrusion pressing the lead wire reaches the area where the conductor of the lead wire was originally located. In this way, by significantly deforming the lead wire by the first protrusion, the holding function of the first protrusion can be further improved.

[0024] The protruding height of the first protrusion may be greater than the thickness of the elastic body. In this case, the lead wire may be significantly deformed by the first protrusion. This further enhances the holding function of the lead wire by the first protrusion. The protruding height of the first protrusion may be, for example, 1 mm or more and 1.5 mm or less. The thickness of the elastic body may be, for example, 0.8 mm or more and 1.0 mm or less.

[0025] At least a portion of the first region on the inner peripheral wall of the second through hole, where the first protrusion is disposed, may have a shape that conforms to the lead wire, while at least a portion of the second region facing the first region may have a shape that moves away from the lead wire as it approaches the cover. The first region and the second region may be regions obtained by dividing the inner peripheral wall of the second through hole into two equal parts along the circumferential direction. In this configuration, the lead wire pressed by the first protrusion can deform so as to escape toward the second region. This can prevent the lead wire from being broken by the pressing force.

[0026] (Motor) A motor according to the present disclosure includes the lead wire holding structure described above. The motor may include a motor main body having a stator and a rotor, a housing that accommodates the motor main body, and an encoder that detects the rotational speed of the rotor, etc. In this configuration, a cover of the lead wire holding structure may cover at least a portion of the encoder, and the lead wires of the lead wire holding structure may be connected to a circuit board of the encoder.

[0027] As described above, according to the present disclosure, the lead wire can be easily and firmly held by the first protrusion provided on the first fixing member. Furthermore, according to the present disclosure, by providing the second protrusion in addition to the first protrusion, the lead wire can be held even more firmly.

[0028] An example of a lead wire holding structure and a motor according to the present disclosure will be described in detail below with reference to the drawings. The components described above can be applied to the components of the example lead wire holding structure and motor described below. The components of the example lead wire holding structure and motor described below can be modified based on the above description. Furthermore, the matters described below may be applied to the above embodiment. Of the components of the example lead wire holding structure and motor described below, components that are not essential to the lead wire holding structure and motor according to the present disclosure may be omitted. Note that the diagrams shown below are schematic and do not accurately reflect the shapes and numbers of actual components.

[0029] Embodiment 1 A description will be given of embodiment 1 of the present disclosure. A motor 10 of this embodiment is configured as a three-phase synchronous motor, but is not limited to this. As shown in Figures 1 to 4, the motor 10 of this embodiment includes a housing 11 and a lead wire holding structure 20.

[0030] An output shaft 12 fixed to the rotor extends from one end (the right end in FIG. 1 ) of the housing 11. A first lead wire 13 is connected to the housing 11 to supply power to a coil in the stator.

[0031] The lead wire holding structure 20 includes a cover 21 , a first fixing member 23 , a second fixing member 27 , a second lead wire 32 , and a packing 35 .

[0032] The cover 21 covers an encoder (not shown) for detecting the rotational speed and rotational angular position of the rotor. The cover 21 has a first through-hole 22 in its upper edge portion. The first through-hole 22 penetrates the upper edge portion of the cover 21 in the thickness direction (roughly the vertical direction in FIG. 2 ). The cover 21 is made of an insulating resin, but is not limited to this.

[0033] The first fixing member 23 is attached to the cover 21. The first fixing member 23 is formed in a generally rectangular plate shape overall. The first fixing member 23 has a second through hole 24 formed in approximately the center of its longitudinal direction (the direction perpendicular to the paper surface in FIGS. 2 and 3B , the left-right direction in FIG. 3A ) and a pair of first insertion holes 25 formed on either side of the second through hole 24. The second lead wire 32 is inserted through the second through hole 24, while screws (not shown) for fixing the first fixing member 23 and the second fixing member 27 to the cover 21 are inserted through each first insertion hole 25.

[0034] The first fixing member 23 has at least one first protrusion 26 (one in this example) that is provided on the inner circumferential wall of the second through hole 24 and presses against an elastic body 34 (described later) of the second lead wire 32. The first protrusion 26 extends in the circumferential direction of the second through hole 24 and is concave toward the radially outer side of the second through hole 24. In this embodiment, the first protrusion 26 is formed in a generally crescent shape in a plan view.

[0035] On the inner peripheral wall of the second through hole 24, at least a portion (in this example, more than half) of the first region 24a where the first protrusion 26 is arranged has a shape that follows the second lead wire 32. Also, on the inner peripheral wall of the second through hole 24, at least a portion (in this example, more than half) of the second region 24b facing the first region 24a has a shape that moves away from the second lead wire 32 as it approaches the cover 21.

[0036] The second fixing member 27 is provided on the side opposite to the side of the first fixing member 23 attached to the cover 21 (the upper side in FIG. 2 ). The second fixing member 27 is attached to the cover 21 together with the first fixing member 23. The second fixing member 27 is formed in a generally rectangular plate shape overall. The second fixing member 27 has a third through hole 28 formed in approximately the center of its longitudinal direction (the direction perpendicular to the paper surface in FIGS. 2 and 4B , the left-right direction in FIG. 4A ) and a pair of second insertion holes 29 formed on either side of the third through hole 28. The second lead wire 32 is inserted through the third through hole 28, and the above-mentioned screws are inserted through each second insertion hole 29.

[0037] The second fixing member 27 has at least one second protrusion 31 (one in this example) that is provided on the inner circumferential wall of the third through hole 28 and presses against the elastic body 34 of the second lead wire 32. The second protrusion 31 extends in the circumferential direction of the third through hole 28 and is concave toward the radially outer side of the third through hole 28. In this embodiment, the second protrusion 31 is formed in a generally crescent shape in a plan view.

[0038] On the inner peripheral wall of the third through hole 28, at least a portion (in this example, more than half) of the third region 28a in which the second protrusion 31 is arranged has a shape that follows the second lead wire 32. Furthermore, on the inner peripheral wall of the third through hole 28, at least a portion (in this example, more than half) of the fourth region 28b facing the third region 28a has a shape that moves away from the second lead wire 32 as it approaches the cover 21.

[0039] The first protrusion 26 of the first fixing member 23 and the second protrusion 31 of the second fixing member 27 press against the elastic body 34 of the second lead wire 32 in opposite directions in the radial direction of the second through hole 24 and the third through hole 28. The first protrusion 26 and the second protrusion 31 are spaced apart from each other in the axial direction of the second through hole 24 and the third through hole 28.

[0040] The deformation amount of the elastic body 34 of the second lead wire 32 caused by the first protrusion 26 is greater than the thickness of the elastic body 34. In addition, the protrusion height H1 of the first protrusion 26 is greater than the thickness of the elastic body 34.

[0041] The deformation amount of the elastic body 34 of the second lead wire 32 caused by the second protrusion 31 is greater than the thickness of the elastic body 34. In addition, the protrusion height H2 of the second protrusion 31 is greater than the thickness of the elastic body 34.

[0042] 2, the second lead wire 32 is illustrated as being generally straight, but in reality, the portions of the second lead wire 32 pressed by the first protrusion 26 and the second protrusion 31 are deformed so as to be curved in the direction of the pressure. For example, in the example of FIG. 2, the portion of the second lead wire 32 pressed by the first protrusion 26 is deformed to the right, while the portion of the second lead wire 32 pressed by the second protrusion 31 is deformed to the left.

[0043] The second lead wire 32 has a conductor 33 for supplying power to the encoder and an insulating elastic body 34 that covers the conductor 33. The second lead wire 32 is inserted through the first through hole of the cover 21, the second through hole 24 of the first fixing member 23, and the third through hole 28 of the second fixing member 27. The second lead wire 32 is an example of a lead wire.

[0044] The packing 35 is provided between the cover 21 and the first fixing member 23, and is in contact with the entire circumference of the second lead wire 32. The packing 35 is formed in a generally cylindrical (or ring) shape that surrounds the second lead wire 32. The packing 35 can prevent moisture and dust from entering the cover 21 from the connection point of the second lead wire 32.

[0045] Second Embodiment A second embodiment of the present disclosure will be described. In a motor 10 of this embodiment, a lead wire holding structure 120 includes a first fixing member 123 that integrates the first fixing member 23 and the second fixing member 27 of the first embodiment. Specifically, as shown in FIG. 5 , the first fixing member 123 of this embodiment has two first protrusions 26. One first protrusion 26 and the other first protrusion 26 press against the elastic body 34 of the second lead wire 32 in opposite directions in the radial direction of the second through hole 24. Furthermore, the one first protrusion 26 and the other first protrusion 26 are spaced apart from each other in the axial direction of the second through hole 24.

[0046] <<Supplementary Note>> The above description of the embodiment discloses the following techniques.

[0047] (Technology 1) A lead wire holding structure comprising: a cover having a first through hole formed therein; a first fixing member attached to the cover and having a second through hole; a lead wire inserted into the first through hole and the second through hole and having a conductor and an insulating elastic body covering the conductor; and a packing provided between the cover and the first fixing member and in contact with the lead wire, wherein the first fixing member is provided on an inner wall of the second through hole and has a first protrusion that presses the elastic body.

[0048] (Technology 2) The lead wire holding structure described in Technology 1 further includes a second fixing member provided on the side of the first fixing member opposite to the side attached to the cover, the second fixing member having a third through hole through which the lead wire is inserted, the second fixing member having a second protrusion provided on an inner circumferential wall of the third through hole that presses the elastic body.

[0049] (Technology 3) The lead wire holding structure according to Technology 2, wherein the first protrusion and the second protrusion press the elastic body in opposite directions to each other in the radial direction of the second through hole and the third through hole.

[0050] (Technology 4) The lead wire holding structure according to Technology 2 or 3, wherein the first protrusion and the second protrusion are spaced apart from each other in the axial direction of the second through hole and the third through hole.

[0051] (Technology 5) The lead wire holding structure according to any one of Technologies 1 to 4, wherein the first protrusions include a first first protrusion and a second first protrusion.

[0052] (Technology 6) The lead wire holding structure according to Technology 5, wherein the first first protrusion and the second first protrusion press the elastic body in opposite directions to each other in the radial direction of the second through hole.

[0053] (Technology 7) The lead wire holding structure according to Technology 5 or 6, wherein the first first protrusion and the second first protrusion are spaced apart from each other in the axial direction of the second through hole.

[0054] (Technology 8) The lead wire holding structure according to any one of Technologies 1 to 7, wherein the first protrusion extends in a circumferential direction of the second through hole and is concave toward the radially outward side of the second through hole.

[0055] (Technology 9) The lead wire holding structure according to any one of Technologies 1 to 8, wherein the deformation amount of the elastic body caused by the first protrusion is greater than the thickness of the elastic body.

[0056] (Technology 10) The lead wire holding structure according to any one of Technologies 1 to 9, wherein the protruding height of the first protrusion is greater than the thickness of the elastic body.

[0057] (Technology 11) A lead wire holding structure according to any one of Technologies 1 to 10, wherein, on the inner peripheral wall of the second through hole, at least a part of a first region in which the first protrusion is arranged has a shape that follows the lead wire, while at least a part of a second region opposite the first region has a shape that moves away from the lead wire as it approaches the cover.

[0058] (Technology 12) A motor comprising the lead wire holding structure according to any one of technologies 1 to 11.

[0059] The present disclosure can be used in lead wire holding structures and motors.

[0060] 10: Motor 11: Housing 12: Output shaft 13: First lead wire 20, 120: Lead wire holding structure 21: Cover 22: First through hole 23, 123: First fixing member 24: Second through hole 24a: First region 24b: Second region 25: First insertion hole 26: First protrusion 27: Second fixing member 28: Third through hole 28a: Third region 28b: Fourth region 29: Second insertion hole 31: Second protrusion 32: Second lead wire (lead wire) 33: Conductive wire 34: Elastic body 35: Packing H1: Protrusion height of first protrusion H2: Protrusion height of second protrusion

Claims

1. A lead wire holding structure comprising: a cover having a first through hole; a first fixing member attached to said cover and having a second through hole; a lead wire inserted into said first through hole and said second through hole and having a conductor and an insulating elastic body covering said conductor; and a packing provided between said cover and said first fixing member and in contact with said lead wire, wherein said first fixing member is provided on an inner wall of said second through hole and has a first protrusion that presses against said elastic body.

2. The lead wire holding structure described in claim 1, further comprising a second fixing member provided on the side of the first fixing member opposite the side attached to the cover and having a third through hole through which the lead wire is inserted, wherein the second fixing member has a second protrusion provided on the inner wall of the third through hole that presses against the elastic body.

3. The lead wire holding structure according to claim 2, wherein the first protrusion and the second protrusion press the elastic body in opposite directions in the radial direction of the second through hole and the third through hole.

4. A lead wire holding structure according to claim 2 or 3, wherein the first protrusion and the second protrusion are spaced apart from each other in the axial direction of the second through hole and the third through hole.

5. The lead wire holding structure according to claim 1, wherein the first protrusions include a first first protrusion and a second first protrusion.

6. The lead wire holding structure according to claim 5, wherein the first first protrusion and the second first protrusion press the elastic body in opposite directions in the radial direction of the second through hole.

7. A lead wire holding structure according to claim 5 or 6, wherein the first first protrusion and the second first protrusion are spaced apart from each other in the axial direction of the second through hole.

8. A lead wire holding structure as described in any one of claims 1 to 3, wherein the first protrusion extends circumferentially around the second through hole and is concave toward the radially outward side of the second through hole.

9. A lead wire holding structure according to any one of claims 1 to 3, wherein the deformation of the elastic body caused by the first protrusion is greater than the thickness of the elastic body.

10. A lead wire holding structure according to any one of claims 1 to 3, wherein the protruding height of the first protrusion is greater than the thickness of the elastic body.

11. A lead wire holding structure as described in any one of claims 1 to 3, wherein at least a portion of a first region in the inner peripheral wall of the second through hole in which the first protrusion is arranged has a shape that follows the lead wire, while at least a portion of a second region opposite the first region has a shape that moves away from the lead wire as it approaches the cover.

12. A motor equipped with the lead wire holding structure according to any one of claims 1 to 3.

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