Motor drive device

Abstract

Provided is a motor drive device including a cover having a structure which can be easily attached to a case and is not easily detached from the case after attachment. This motor drive device comprises: an active electric part; a case that accommodates the active electric part and has an opening; a cover that is attached to the case and is configured to cover the opening of the case; at least one projection that is formed in one of the case and the cover; and at least one recess that is formed on the other of the case and the cover and into which the projection fits. The projection has a first tapered surface that is inclined so that the height of the projection decreases along the mounting direction of the projection with respect to the recess. Alternatively, or in addition, the recess has a tapered groove that is inclined so that the depth decreases along the mounting direction.

Description

Motor drive unit

[0001] The present disclosure relates to a motor drive device.

[0002] Motor drives are known as drives for driving motors used in applications such as driving the axes of machine tools and robots. A typical motor drive includes electronic components such as power elements and capacitors for supplying current to the motor. The motor drive also includes bus bars made of metals such as copper, brass, or aluminum, and fixed terminals for mounting the bus bars on a circuit board or the like, as electrical connection means for these electronic components.

[0003] The bus bars are disposed in a case made by, for example, resin molding. Since the bus bars may be mounted by the user, one type of motor drive device has a case that houses a board on which the bus bars are mounted and has an opening that allows the user to access the bus bars on the board, and a cover that covers the opening of the case to protect the bus bars.

[0004] JP 04-162598 A JP 2018-032719 A JP 2019-213419 A

[0005] The cover of the motor drive device is attached to the case after the user has mounted the bus bars on the circuit board inside the case, so it is preferable that the cover be easy to attach.However, because a large current can flow through the bus bars, it is undesirable for the cover to be easily detached from the case from the standpoint of safety, such as preventing electric shock.

[0006] Therefore, there is a demand for a motor drive device that is provided with a cover that is easy to attach to the case, but has a structure that makes it difficult to remove from the case once attached.

[0007] One aspect of the present disclosure is a motor drive device having an active part, a case that houses the active part and has an opening, a cover that is attached to the case and configured to cover the opening of the case, at least one protrusion formed on one of the case or the cover, and at least one recess formed on the other of the case or the cover into which the protrusion fits, wherein the protrusion has a first tapered surface that slopes so that the height of the protrusion decreases along the attachment direction of the protrusion relative to the recess, and the recess has a tapered groove that slopes so that the depth decreases along the attachment direction.

[0008] 14 is a schematic perspective view of a motor drive device according to an embodiment. FIG. 14 is a perspective view of the vicinity of the cover according to the first embodiment. FIG. 14 is a partially enlarged view of the cover of FIG. 2. FIG. 14 is a partially enlarged view of the cover of FIG. 2. FIG. 14 is a perspective view of the vicinity of the cover according to the second embodiment. FIG. 14 is a partially enlarged view of the cover of FIG. 5. FIG. 14 is a perspective view of the vicinity of the cover according to the third embodiment. FIG. 14 is a partially enlarged view of the cover of FIG. 7. FIG. 14 is a perspective view of the vicinity of the cover according to the fourth embodiment. FIG. 14 is a partially enlarged view of the cover of FIG. 9. FIG. 14 is a perspective view of the cover and case of FIG. 9, viewed from a different angle. FIG. 14 is a perspective view showing the cover of FIG. 11 rotated 90 degrees. FIG. 14 is a perspective view of the vicinity of the cover according to the fifth embodiment. FIG. 14 is a partially enlarged view of the cover of FIG. 13. FIG. 14 is a perspective view of the vicinity of the joint between the cover and case according to the sixth embodiment. FIG. 14 is a perspective view of the cover and case of FIG. 15, viewed from a different angle. FIG. 14 is a perspective view of the vicinity of the cover according to the seventh embodiment. FIG. 14 is a partially enlarged view of the cover of FIG. 17. FIG. 14 is a perspective view of the vicinity of the cover according to the eighth embodiment. FIG. 14 is a schematic perspective view of a motor drive device according to the ninth embodiment. FIG. 14 is a top view of the motor drive device of FIG. 19. FIG. 15 is a perspective view of the vicinity of the cover according to the tenth embodiment. FIG. 15 is an enlarged view of the locking mechanism of the cover of FIG. 22 26. A perspective view of the vicinity of the cover according to the 11th embodiment. An enlarged view of the locking mechanism of the cover of FIG. 25. A cross-sectional view taken along line XXVII-XXVII of FIG. 26. A perspective view of the vicinity of the cover according to the 12th embodiment. A cross-sectional view taken along line XXIX-XXIX of FIG. 28. An enlarged view of the locking mechanism of the cover of FIG. 28. A view of the locking mechanism of the cover of FIG. 28 from the back side. A perspective view of the vicinity of the cover according to the 13th embodiment. An enlarged view of the locking mechanism of the cover of FIG. 32.

[0009] FIG. 1 is a perspective view showing the schematic configuration of a motor drive device 10 according to a preferred embodiment. The motor drive device 10 is a device for driving a motor 2, shown schematically, and has an overall substantially rectangular parallelepiped shape. The motor 2 is, for example, a motor such as a servo motor that drives each axis of a machine tool or robot. The motor drive device 10 includes a case 12, a circuit board 14 mounted inside the case 12 and carrying electronic components such as power elements (not shown), a bus bar 16 made of a metal such as copper, brass, or aluminum as an electrical connection means for the electronic components, and fixed terminals 18 and associated terminal blocks for securing the bus bar 16 to the circuit board. In this disclosure, the bus bar 16, the fixed terminals 18, and other components through which current can flow and their associated components are collectively referred to as "live parts." The motor drive device 10 optionally includes a flange 20, a cooling fan 22, and at least one connector 24 to which a cable (not shown) for power supply or signal communication can be attached or detached to the motor drive device 10.

[0010] 2, the case 12 has an opening 26 that allows a user or operator of the motor drive device (hereinafter simply referred to as the user) to access the board 14 for purposes such as mounting the bus bar 16, and the motor drive device 10 has a cover 28 that is configured to be attachable to the case 12 and that covers the opening 26 to protect live parts inside the case 12. The case 12 and cover 28 are resin products that can be made by resin molding, for example, but may be made from any material that has the actions and functions described below.

[0011] The cover 28 is configured to be attached to the case 12 and cover the opening 26 of the case 12 by moving it in a predetermined attachment direction 30 relative to the case 12. A protrusion 32 is formed on one of the case 12 or the cover 28, and a recess 34 into which the protrusion 32 fits is formed on the other of the case 12 or the cover 28. Furthermore, the motor drive device 10 according to the present disclosure satisfies at least one of the following: the protrusion 32 has a tapered surface that slopes so that the height of the protrusion 32 decreases along the attachment direction 30 relative to the recess 34; and the recess 34 has a tapered groove that slopes so that the depth decreases along the attachment direction 30. Each embodiment according to the present disclosure will be described below.

[0012] 2-4 are a perspective view of the vicinity of the cover 28 of a motor drive device according to a first embodiment, a partially enlarged view of the cover 28, and a partially enlarged view of FIG. 2, respectively. The cover 28 has two arms 36, and a substantially cylindrical protrusion 32 is formed on each arm 36. Meanwhile, the case 12 has a stepped portion 38 that receives the arms 36 when the cover 28 is attached, and a substantially cylindrical recess 34 is formed in the stepped portion 38, into which the protrusion 32 fits. The recess 34 further has a tapered groove 40 that slopes so that its depth decreases along the attachment direction 30.

[0013] When the cover 28 is moved relative to the case 12 in the mounting direction 30, the protrusions 32 slide within the tapered grooves 40, and as a result, the arms 36 elastically deform in a direction gradually widening outward in the width direction. When the cover 28 is moved further, the protrusions 32 climb over the tapered grooves 40 and fit into the recesses 34, and the cover 28 is mounted to the case 12. That is, in the first embodiment, the tapered grooves 40 function as guides that make it easy to fit the protrusions 32 into the recesses 34.

[0014] The protrusions 32 do not have tapered surfaces, and the recesses 34 do not have tapered grooves whose depth decreases in the direction opposite to the mounting direction 30. Therefore, the first embodiment does not have a structure that makes it easy to remove the cover 28 (the protrusions 32) from the case 12 (the recesses 34), and therefore it is relatively difficult to remove the cover 28 once it has been mounted on the case 12. This prevents the cover 28 from unintentionally coming off the case 12, which could result in insufficient protection of live parts inside the case 12.

[0015] In the first embodiment, the cover 28 can be rotated relative to the case 12 using the protrusion 32 as a fulcrum. The motor drive device 10 also preferably has a locking mechanism to prevent the cover 28 from unintentionally rotating relative to the case 12, which will be described later.

[0016] 5 and 6 are a perspective view of the vicinity of cover 28a of a motor drive device according to a second embodiment, and a partially enlarged view of cover 28a, respectively. Note that in the second embodiment, only the parts that differ from the first embodiment will be described, and parts that are similar to those in the first embodiment will be given the same reference numerals and will not be described in detail.

[0017] Cover 28a has two arms 36, and a substantially cylindrical protrusion 32a is formed on each arm 36. Meanwhile, case 12a has a stepped portion 38 that receives arm 36 when cover 28 is attached, and a substantially cylindrical recess 34 into which protrusion 32a fits is formed in stepped portion 38. Protrusion 32a also has a first tapered surface 42 that slopes so that the height of protrusion 32a decreases along attachment direction 30 of protrusion 32a relative to recess 34.

[0018] When the cover 28a is moved relative to the case 12a in the mounting direction 30, the first tapered surface 42 of the protrusion 32a slides on the step portion 38, and as a result, the arm 36 elastically deforms in a direction gradually widening outward in the width direction. When the cover 28a is moved further, the protrusion 32a fits into the recess 34, and the cover 28a is mounted to the case 12a. That is, in the first embodiment, the first tapered surface 42 functions as a guide portion that makes it easy to fit the protrusion 32a into the recess 34.

[0019] The protrusions 32a do not have a tapered surface that would facilitate attachment and detachment of the cover 28a (i.e., a slope that reduces the height of the protrusions 32a in the direction opposite the attachment direction 30), and the recesses 34 do not have a tapered groove or the like that reduces in depth in the direction opposite the attachment direction 30. Therefore, the second embodiment also does not have a structure that facilitates removing the cover 28a (the protrusions 32a) from the case 12a (the recesses 34), making it relatively difficult to remove the cover 28a once it has been attached to the case 12a. This prevents the cover 28a from unintentionally coming off the case 12a, thereby preventing the live parts inside the case 12a from being insufficiently protected.

[0020] It is also possible to combine the first and second embodiments. That is, it is possible to combine the case 12 of the first embodiment with the cover 28a of the second embodiment to form a motor drive device having both the tapered groove 40 and the tapered surface 42.

[0021] 7 and 8 are a perspective view of the vicinity of cover 28b of a motor drive device according to a third embodiment, and a partially enlarged view of cover 28b, respectively. Note that in the third embodiment, only the parts that differ from the first embodiment will be described, and parts that are similar to those in the first embodiment will be assigned the same reference numerals and will not be described in detail.

[0022] The cover 28b has two arms 36, each of which has a substantially hemispherical protrusion 32b. Meanwhile, the case 12 has a stepped portion 38 that receives the arms 36 when the cover 28 is attached, and the stepped portion 38 has a substantially cylindrical recess 34 into which the protrusion 32 fits. The recess 34 further has a tapered groove 40 that slopes downward in the attachment direction 30.

[0023] When cover 28b is moved relative to case 12 in mounting direction 30, hemispherical surface 44 of protrusion 32b slides within tapered groove 40, and as a result, arm 36 elastically deforms in a direction gradually widening outward in the width direction. When cover 28b is moved further, protrusion 32b fits into recess 34, and cover 28b is mounted to case 12. That is, in the third embodiment, hemispherical surface 44 functions as a guide that makes it easy to fit protrusion 32b into recess 34.

[0024] Since the hemispherical surface 44 can be considered a tapered surface that is inclined in a substantially arbitrary direction, the protrusion 32b can be considered to have a tapered surface that facilitates attachment and detachment of the cover 28b. However, since the recess 34 does not have a tapered groove or the like that decreases in depth in the direction opposite to the attachment direction 30, the third embodiment also prevents the cover 28b from unintentionally coming off the case 12, which would result in insufficient protection of live parts inside the case 12.

[0025] 9 and 10 are a perspective view of the vicinity of cover 28c of a motor drive device according to a fourth embodiment, and a partially enlarged view of cover 28c, respectively. Note that in the fourth embodiment, only the parts that differ from the first embodiment will be described, and parts that are the same as those in the first embodiment will be assigned the same reference numerals and will not be described in detail.

[0026] The cover 28c has two arms 36, each of which has a substantially cylindrical protrusion 32c. Meanwhile, the case 12c has a stepped portion 38 that receives the arm 36 when the cover 28c is attached, and a substantially cylindrical recess 34 into which the protrusion 32c fits is formed in the stepped portion 38. The protrusion 32c has a tapered surface 46 that slopes so that the height of the protrusion 32c decreases along the attachment direction of the protrusion 32c relative to the recess 34, and a second tapered surface 48 that slopes in a different direction from the tapered surface 46, but the slope of the second tapered surface 48 is not 180 degrees opposite the slope of the first tapered surface 46. The recess 34 may further have a guide groove 50 that facilitates movement of the protrusion 32c in the attachment direction 30.

[0027] FIG. 11 is a partially enlarged view of the case 12c and the cover 28c, viewed from a different direction than FIG. 9 . When the cover 28c is moved relative to the case 12c in the mounting direction 30, the tapered surface 46 of the protrusion 32c slides over the step portion 38 or within the guide groove 50, fitting the protrusion 32c into the recess 34, and the cover 28c is mounted to the case 12c. That is, in the fourth embodiment, the first tapered surface 46 functions as a guide that facilitates fitting the protrusion 32c into the recess 34. If the width W of the guide groove 50 is set slightly smaller than the diameter of the recess 34, the protrusion 32c will not easily come out of the recess 34 after fitting. However, because the first tapered surface 46 functions as a guide during mounting, the protrusion 32c can be fitted relatively smoothly into the recess 34 even if the width W is slightly smaller than the diameter of the recess 34.

[0028] The protrusions 32c do not have a tapered surface that would facilitate attachment and detachment of the cover 28c (i.e., a slope that reduces the height of the protrusions 32c in the direction opposite to the attachment direction 30). Therefore, the fourth embodiment also does not have a structure that facilitates removing the cover 28c (the protrusions 32c) from the case 12c (the recesses 34), and therefore, once the cover 28c is attached to the case 12c, the cover 28c is prevented from unintentionally coming off the case 12c, which would result in insufficient protection of live parts inside the case 12c.

[0029] However, the fourth embodiment includes a structure that makes it easier for the user to intentionally remove the cover 28c from the case 12c. Specifically, the second tapered surface 48 described above is not a tapered surface that facilitates the attachment and detachment of the cover 28c (i.e., a surface that slopes so that the height of the protrusion 32c decreases in the direction opposite to the attachment direction 30), but it is sloped in a different direction (e.g., 90 degrees) than the first tapered surface 46. Therefore, as shown in FIG. 12 , with the protrusion 32c fitted in the recess 34, the cover 28c is rotated about the protrusion 32c as a fulcrum by a predetermined angle (90 degrees in this case) other than 180 degrees, and then the cover 28c is moved in the direction 31 opposite to the attachment direction 30. This causes the second tapered surface 48 to function as a guide that promotes removal from the recess 34, allowing the cover 28c to be smoothly removed.

[0030] 13 and 14 are a perspective view of the vicinity of cover 28d of a motor drive device according to a fifth embodiment, and a partially enlarged view of cover 28d, respectively. Note that in the fifth embodiment, only the parts that differ from the third embodiment will be described, and parts that are similar to those in the third embodiment will be assigned the same reference numerals and will not be described in detail.

[0031] The cover 28d has two arms 36, each of which has a substantially hemispherical protrusion 32d. The case 12d has a stepped portion 38 that receives the arms 36 when the cover 28d is attached, and the stepped portion 38 has a substantially cylindrical recess 34 into which the protrusion 32d fits. The recess 34 further has a tapered groove 40 that slopes downward in the attachment direction 30.

[0032] When cover 28d is moved relative to case 12d in mounting direction 30, hemispherical surface 44 of protrusion 32d slides within tapered groove 40, causing arm 36 to elastically deform in a direction gradually widening. When cover 28d is moved further, protrusion 32d fits into recess 34, and cover 28d is mounted to case 12. That is, in the fifth embodiment, hemispherical surface 44 functions as a guide that makes it easy to fit protrusion 32d into recess 34.

[0033] The fifth embodiment has a structure for holding the cover 28d in an open state. Specifically, as shown in Fig. 14, the projection 32d has a ridge-like convex portion 52 adjacent to its outer periphery, while the case 12d has a first concave portion 54 (preferably of a shape complementary to the convex portion 52) formed adjacent to the outer periphery of the recess 34 and into which the convex portion 52 fits when the cover 28d is attached. The case 12d further has a second concave portion 56, which has substantially the same shape as the first concave portion 54, adjacent to the outer periphery of the recess 34 and is formed at a different angular position from the first concave portion 54 (an angular position different by 90 degrees in the illustrated example).

[0034] In the fifth embodiment, when the cover 28d is attached to the case 12d, the convex portion 52 fits into the first concave portion 54, ensuring stable attachment of the cover 28d. On the other hand, when the user needs to access live components inside the case 12d, the user does not have to completely remove the cover 28d from the case 12d; instead, the user simply rotates the cover 28d by a predetermined angle (here, 90 degrees) around the protrusion 32d as a fulcrum, causing the convex portion 52 to fit into the second concave portion 56, thereby maintaining the cover 28d in an open state. This allows the user to perform work efficiently with minimal effort.

[0035] In the fifth embodiment, there is one convex portion 52 adjacent to the protrusion 32d and two concave portions 54, 56 adjacent to the recess 34, but this is not limiting. For example, a configuration having two concave portions adjacent to the protrusion 32d and one convex portion adjacent to the recess 34 is also possible.

[0036] 15 and 16 are perspective views of the vicinity of the joint between the cover and the case in a motor drive device according to Example 6, viewed from different angles. Note that in Example 6, only the parts that differ from Example 5 will be explained, and parts that are the same as those in Example 5 will be given the same reference numerals and will not be explained in detail.

[0037] The case 12e according to the sixth embodiment differs from the case 12d of the fifth embodiment only in that it has a groove 58 through which the protrusion 52 passes when the cover 28d similar to that of the fifth embodiment is attached, but other parts may be the same as the case 12d. Specifically, the case 12e has a groove 58 that extends toward the outside of the case 12e adjacent to the recess 34, and in the illustrated example, the groove 58 is formed to a predetermined depth in the tapered groove 40. When the cover 28d is attached, the protrusion 52 passes through the groove 58, which makes it easier to attach the cover 28d.

[0038] 17 and 18 are a perspective view of the vicinity of cover 28f of a motor drive device according to a seventh embodiment, and a partially enlarged view of cover 28f, respectively. Note that in the seventh embodiment, only the parts that differ from the second embodiment will be described, and parts that are similar to those in the second embodiment will be given the same reference numerals and will not be described in detail.

[0039] Cover 28f has two arms 36, and a substantially cylindrical protrusion 32f is formed on each arm 36. Meanwhile, case 12f has a stepped portion 38 that receives arm 36 when cover 28f is attached, and a substantially cylindrical recess 34 into which protrusion 32f fits is formed in stepped portion 38. Protrusion 32f also has a tapered surface 42 that slopes so that the height of protrusion 32f decreases along the attachment direction 30 of protrusion 32f relative to recess 34.

[0040] When cover 28f is moved relative to case 12f in mounting direction 30, tapered surface 42 of protrusion 32f slides on step portion 38, causing arm 36 to elastically deform in a direction gradually widening. When cover 28f is moved further, protrusion 32f fits into recess 34, and cover 28f is mounted to case 12f. That is, in the seventh embodiment, tapered surface 42 functions as a guide that makes it easy to fit protrusion 32f into recess 34.

[0041] The seventh embodiment, like the fifth or sixth embodiment, has a structure for holding the cover 28f in an open state. Specifically, as shown in Fig. 18, the protrusion 32f has a first recess 60 adjacent to its outer periphery, and a second recess 61 that is adjacent to the outer periphery of the protrusion 32f and is formed at a different angular position from the first recess 60 (an angular position that differs by 90 degrees in the illustrated example), and that has substantially the same shape as the first recess 60. Meanwhile, the case 12f has a protrusion 62 formed adjacent to the outer periphery of the recess 34 and that fits into the first recess 60 when the cover 28f is attached.

[0042] In the seventh embodiment, when the cover 28f is attached to the case 12f, the convex portion 62 fits into the first concave portion 60, ensuring stable attachment of the cover 28f. On the other hand, when the user needs to access live components inside the case 12f, the user does not need to completely remove the cover 28f from the case 12f; instead, the user can simply rotate the cover 28f by a predetermined angle (here, 90 degrees) around the protrusion 32f as a fulcrum, causing the convex portion 62 to fit into the second concave portion 61, thereby maintaining the cover 28f in an open state. This allows the user to perform work efficiently with minimal effort.

[0043] In the seventh embodiment, there are two recesses 60, 61 adjacent to the protrusion 32f and one protrusion 62 adjacent to the recess 34, but this is not limiting. For example, a configuration having one protrusion adjacent to the protrusion 32f and two recesses adjacent to the recess 34 is also possible.

[0044] All of the first to seventh embodiments described above have a structure that allows the cover to be easily attached to the case, more specifically, allows the protrusion formed on the cover to fit easily into the recess formed in the case, while preventing the cover from easily coming off the case. Therefore, the cover can be rotated around the protrusion as a fulcrum through a predetermined angle when attached to the case, but can also be fixed so as not to rotate relative to the case using a locking mechanism, which will be described later. However, the present disclosure is not limited to this; for example, it is also possible to form a recess in the cover and a protrusion on the case. Furthermore, the tapered surface may be a curved surface.

[0045] 19 is a perspective view of the vicinity of the cover 28g of a motor drive device 10g according to Example 8. Example 8 has a structure that allows the cover to be opened and closed smoothly in the above-described fifth to seventh examples, i.e., examples that have protrusions and recesses that hold the cover open relative to the case.

[0046] Specifically, the cover 28g according to the eighth embodiment has notches 64 and 66 formed near each of the arms 36. The notches 64 and 66 facilitate elastic deformation of the arms 36 when the cover 28g is attached to the case 12, thereby facilitating a series of actions, such as the protrusion 52 shown in FIG. 13 moving from within the first recess 54 onto the step 38 and fitting into the second recess 56 when the cover is rotated. Furthermore, because the arms 36 are more easily flexible, wear on the protrusion 52 during the opening and closing of the cover is reduced, the life of the cover is extended, and the retention function of the protrusion 52 and the recesses 54, 56 is maintained over a long period of time.

[0047] 20 and 21 are a perspective view and a top view, respectively, of a motor drive device 10h according to a ninth embodiment. Like the eighth embodiment, the ninth embodiment also has a structure that allows for smooth opening and closing of the cover in the fifth to seventh embodiments described above. However, in the ninth embodiment, the case has a divided structure consisting of a first case portion 12h1 and a second case portion 12h2, and a minute gap 70 is provided between the first case portion 12h1 and the second case portion 12h2 on the pivot axis 68 of the cover 28.

[0048] Because the gap 70 makes it easier for the case to bend in the direction of the pivot axis 68, even if the cover 28 is relatively rigid and difficult to bend, a series of actions is promoted in which, as in the eighth embodiment, the convex portion 52 shown in Fig. 13 moves from inside the first concave portion 54 onto the step portion 38 and fits into the second concave portion 56 when the cover is pivoted. Furthermore, because the case is more flexible, wear on the convex portion 52 during the opening and closing operation of the cover is reduced, the life of the cover is extended, and the holding function of the convex portion 52 and the concave portions 54, 56 is maintained for a long period of time.

[0049] In the ninth embodiment, instead of making the case a divided structure, a notch can be formed in the case near the joint with the cover 28 to make the case more flexible. The ninth embodiment can also be combined with the eighth embodiment.

[0050] 22 is a perspective view of the vicinity of the cover 28 of a motor drive device according to Example 10. The cover 28 has a locking mechanism 72 that fixes the cover 28 so that it does not rotate relative to the case 12.

[0051] 23 and 24 are an enlarged view and a cross-sectional view taken along line XXIV-XXIV in Fig. 23, respectively, of the locking mechanism 72. The locking mechanism 72 has a U-shaped portion 78 that extends in a generally U-shape within a recess 76 formed by cutting out a portion of one side (here, the bottom side 74) of the cover 28, a grip portion 80 that is formed at the tip of the U-shaped portion 78 and extends further forward than the bottom side 74, and a latch portion 82 that is formed on the U-shaped portion 78 and extends downward beyond the bottom side 74.

[0052] In the tenth embodiment, the user can grasp and lift the grip portion 80 so that the U-shaped portion 78 elastically deforms upward, and engage the latch portion 82 with the case 12, thereby fixing the cover 28 so that it does not rotate relative to the case 12.

[0053] 25 is a perspective view of the vicinity of cover 28i of a motor drive device according to an eleventh embodiment. Cover 28i has a locking mechanism 72i that fixes cover 28i so that it does not rotate relative to case 12. Note that in the eleventh embodiment, only the parts that differ from the tenth embodiment will be described, and parts that are similar to those in the tenth embodiment will be given the same reference numerals and will not be described in detail.

[0054] 26 and 27 are an enlarged view of the locking mechanism 72i and a cross-sectional view taken along line XXVII-XXVII in Fig. 26. The locking mechanism 72i has a U-shaped portion 78i that extends in a generally U-shape within a recess 76 formed by cutting out a portion of one side (here, the bottom side 74) of the cover 28i, a gripping portion 80i that is formed at the tip of the U-shaped portion 78i and extends further forward than the bottom side 74, and a latch portion 82i that is formed on the U-shaped portion 78i and extends downward beyond the bottom side 74.

[0055] If the grip portion 80i is pushed in or lifted excessively to engage or disengage the latch portion 82i, the grip portion 80i or the U-shaped portion 78i may be damaged. Therefore, the cover 28i has a stopper 83 extending toward the grip portion 80i, approximately at the center of the width of the U-shaped portion 78i (the direction of deformation of the U-shaped portion 78i). The stopper 83 is configured to abut against the grip portion 80i and restrict displacement of the grip portion 80i if an attempt is made to displace the grip portion 80i unnecessarily, thereby preventing damage to the locking mechanism 72i due to displacement of the grip portion 80i. The U-shaped portion 78i preferably has a notch 84 so that elastic deformation is not hindered by the stopper 83.

[0056] 28 is a perspective view of the vicinity of cover 28j of a motor drive device according to a twelfth embodiment. Cover 28j has a locking mechanism 72j that fixes cover 28j so that it does not rotate relative to case 12. Note that in the twelfth embodiment, only the parts that differ from the eleventh embodiment will be described, and parts that are similar to those in the eleventh embodiment will be given the same reference numerals and will not be described in detail.

[0057] 29 and 30 are a cross-sectional view taken along line XXIX-XXIX in Fig. 28 and an enlarged view of the locking mechanism 72j, respectively. The locking mechanism 72j has a U-shaped portion 78j that extends in a generally U-shape within a recess 76 formed by cutting out a portion of one side (here, the bottom side 74) of the cover 28j, a gripping portion 80j that is formed at the tip of the U-shaped portion 78j and extends forward beyond the bottom side 74, and a latch portion 82j that is formed on the U-shaped portion 78j and extends downward beyond the bottom side 74.

[0058] 29, it is preferable that the radius of curvature of the U-shaped portion 78j is as large as possible so that it can bend significantly even with a small force. Furthermore, rather than making the thickness of the entire U-shaped portion 78j uniform, it is possible to make the U-shaped portion 78j more easily bendable by making a portion 86 thinner than the other portions.

[0059] 30 shows an example in which a stopper 88 is formed on the locking mechanism 72j. Stepped portions 88 are formed as stoppers on both sides of the recess 76 in the width direction (the direction of deformation of the U-shaped portion 78i), and widened portions 90 are formed on both sides of the U-shaped portion 78j in the width direction. With this structure, when the U-shaped portion 78j elastically deforms by a certain amount or more, the widened portions 90 come into contact with the stepped portions 88, suppressing further deformation of the U-shaped portion 78j. Therefore, damage to the U-shaped portion 78j and other components is prevented even if the user applies a relatively large force to the grip portion 80j. Furthermore, in the twelfth embodiment, there is no need to provide a notch in the U-shaped portion 78j, and therefore, undesirable stress concentration does not occur.

[0060] 31 shows an example in which a reinforcing rib 92 is provided on the back side of the cover 28j in addition to the locking mechanism 72j. By forming the ribs 92 at the connection points between the U-shaped portion 78j and the recess 76 on both sides of the width of the U-shaped portion 78j, the probability of damage to the U-shaped portion 78j can be significantly reduced even if an unexpected force is applied to the U-shaped portion 78j. In this way, the twelfth embodiment provides a cover that allows the locking mechanism 72j to be opened and closed (the U-shaped portion 78j to elastically deform) with a relatively small force, and that is less likely to damage the U-shaped portion 78j even if an excessive force is applied.

[0061] 32 is a perspective view of the vicinity of cover 28k of a motor drive device according to Example 13. Cover 28k has a locking mechanism 94 that fixes cover 28k so that it does not rotate relative to case 12, but the locking mechanism 94 is configured so that it cannot be opened or closed by the user with bare hands.

[0062] Specifically, as shown in FIG. 33 , the locking mechanism 94 is formed to extend downward from one side of the cover 28k (here, the bottom side 74) and is configured to engage with (the upper end of) the case 12 to secure the cover 28k to the case 12. The locking mechanism 94 also has a recess 96 into which a tapered tool or the like can be inserted. When the cover 28k is properly attached to the case 12 ( FIG. 32 ), that is, when the locking mechanism 94 is engaged with the case 12, the locking mechanism 94 cannot be removed from the case 12 unless a tool or the like is inserted into the recess 96. As such, in the thirteenth embodiment, the cover 28k cannot be removed from the case 12 unless the user performs an operation using a tool or the like. This prevents the cover 28k from opening or removing unintentionally, thereby improving the safety of the motor drive device.

[0063] The above-described embodiments can be combined as appropriate. For example, any of the locking mechanisms of the tenth to thirteenth embodiments can be applied to any of the first to seventh embodiments.

[0064] According to the present disclosure, a motor drive device is provided that includes a cover that is easily attached to a case due to protrusions and recesses with special structures, while being difficult to unintentionally remove from the case once attached. Furthermore, by providing a notch in at least one of the case or cover, flexibility of the case or cover is promoted, making it easier to attach the cover. Furthermore, by allowing the cover to pivot relative to the case using the protrusion as a fulcrum and providing a locking mechanism that secures the cover to the case, a motor drive device with excellent operability is provided.

[0065] Although the present disclosure has been described in detail, the present disclosure is not limited to the individual embodiments described above. Various additions, substitutions, modifications, partial deletions, etc. are possible in these embodiments without departing from the gist of the present disclosure or the spirit of the present disclosure derived from the content of the claims and their equivalents. These embodiments can also be implemented in combination. For example, in the above-described embodiments, the order of each operation and the order of each process are shown as examples and are not limited to these. The same applies when numerical values ​​or mathematical expressions are used in the description of the above-described embodiments.

[0066] The following additional notes are provided regarding the above-described embodiment and modifications.

[0067] (Supplementary Note 1) A motor drive device comprising: an active part; a case that houses the active part and has an opening; a cover that is attached to the case and configured to cover the opening of the case; at least one protrusion formed on one of the case or the cover; and at least one recess that is formed on the other of the case or the cover and into which the protrusion fits, wherein the protrusion has a first tapered surface that slopes so that the height of the protrusion decreases along the attachment direction of the protrusion relative to the recess; and the recess has a tapered groove that slopes so that the depth decreases along the attachment direction.

[0068] (Supplementary Note 2) The motor drive device according to Supplementary Note 1, wherein at least one of the protrusion and the recess has a cylindrical shape, and the cover is configured to be rotatable relative to the case with the protrusion as a fulcrum.

[0069] (Supplementary Note 3) The motor drive device according to Supplementary Note 2, wherein the protrusion has the first tapered surface, and the recess has a groove having a width smaller than a diameter of the recess.

[0070] (Supplementary Note 4) The motor drive device according to Supplementary Note 2 or 3, wherein the protrusion has the first tapered surface and a second tapered surface that is inclined in a direction different from that of the first tapered surface.

[0071] (Appendix 5) A motor drive device as described in Appendix 2, comprising at least one convex portion formed on one of the case or the cover, and at least one concave portion formed on the other of the case or the cover, the convex portion and the concave portion being arranged and configured such that the cover is held in an open state relative to the case by fitting the convex portion into the concave portion.

[0072] (Supplementary Note 6) The motor drive device according to Supplementary Note 5, wherein the case has a groove adjacent to the recess and extending toward an outside of the case.

[0073] (Supplementary Note 7) The motor drive device according to Supplementary Note 1, wherein at least one of the case and the cover has a notch that promotes bending of the case or the cover.

[0074] (Appendix 8) The motor drive device described in Appendix 2, wherein the case has a divided structure consisting of a first case portion and a second case portion, and a gap is formed between the first case portion and the second case portion on the pivot axis of the cover relative to the case.

[0075] (Supplementary Note 9) The motor drive device according to Supplementary Note 2, wherein the cover has a locking mechanism that fixes the cover to the case.

[0076] (Supplementary Note 10) The motor drive device according to Supplementary Note 9, wherein the locking mechanism has an elastically deformable U-shaped portion and a grip portion formed on the U-shaped portion and engageable with the case.

[0077] (Supplementary Note 11) The motor drive device according to Supplementary Note 10, wherein the locking mechanism has a stopper that restricts displacement of the gripping portion, at approximately the center in a width direction perpendicular to the elastic deformation direction of the U-shaped portion.

[0078] (Supplementary Note 12) The motor drive device according to Supplementary Note 10, wherein the locking mechanism has stoppers that restrict displacement of the gripping portion on both sides in a width direction perpendicular to the elastic deformation direction of the U-shaped portion.

[0079] (Supplementary Note 13) The motor drive device according to Supplementary Note 9, wherein the locking mechanism is configured to be openable and closable by using a tool.

[0080] 2 Motor 10 Motor drive device 12 Case 12h1, 12h2 Case portion 14 Board 16 Bus bar 18 Fixed terminal 28 Cover 32 Protrusion 34 Recess 36 Arm 40 Tapered groove 42, 46, 46 Tapered surface 50 Guide groove 52, 62 Convex portion 54, 56, 60, 61 Recess 58 Groove 64, 66 Notch

Claims

1. A motor drive device having an active part, a case that houses the active part and has an opening, a cover that is attached to the case and configured to cover the opening of the case, at least one protrusion formed on one of the case or the cover, and at least one recess formed on the other of the case or the cover into which the protrusion fits, wherein at least one of the protrusion has a first tapered surface that slopes so that the height of the protrusion decreases along the attachment direction of the protrusion relative to the recess, and the recess has a tapered groove that slopes so that the depth decreases along the attachment direction.

2. The motor drive device according to claim 1, wherein at least one of the projection and the recess has a cylindrical shape, and the cover is configured to be rotatable relative to the case with the projection as a fulcrum.

3. The motor drive device according to claim 2, wherein said projection has said first tapered surface, and said recess has a groove having a width smaller than a diameter of said recess.

4. A motor drive device according to claim 2 or 3, wherein said projection has said first tapered surface and a second tapered surface having an inclination direction different from that of said first tapered surface.

5. A motor drive device as described in claim 2, comprising at least one convex portion formed on one of the case or the cover, and at least one concave portion formed on the other of the case or the cover, the convex portion and the concave portion being arranged and configured such that the cover is held in an open position relative to the case by the convex portion fitting into the concave portion.

6. The motor drive device according to claim 5, wherein said case has a groove adjacent to said recess and extending toward the outside of said case.

7. The motor drive device according to claim 1, wherein at least one of the case or the cover has a notch that promotes flexure of the case or the cover.

8. A motor drive device as described in claim 2, wherein the case has a divided structure consisting of a first case portion and a second case portion, and a gap is formed between the first case portion and the second case portion on the pivot axis of the cover relative to the case.

9. The motor drive device according to claim 2, wherein the cover has a locking mechanism for fixing the cover to the case.

10. The motor drive device according to claim 9, wherein the locking mechanism has an elastically deformable U-shaped portion and a gripping portion formed on the U-shaped portion and engageable with the case.

11. The motor drive device according to claim 10, wherein the locking mechanism has a stopper for restricting displacement of the gripping portion, located approximately at the center in the width direction perpendicular to the direction of elastic deformation of the U-shaped portion.

12. The motor drive device according to claim 10, wherein the locking mechanism has stoppers for restricting displacement of the gripping portion on both sides in a width direction perpendicular to the elastic deformation direction of the U-shaped portion.

13. The motor drive device according to claim 9, wherein the locking mechanism is configured to be capable of being opened and closed by using a tool.

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