Electric motor

Abstract

The present application relates to an electric motor having a stator core, a housing, a guide ring, and a sealing member. The guide ring has an annular shape and is sandwiched between the end surface of the stator core and the opposing portion. The sealing member is provided on a target interface that is at least one of an interface between the guide ring and the end surface and an interface between the guide ring and the facing portion. A space enclosed by the inner surface of the housing, the outer peripheral surface of the guide ring, and the end surface forms an annular cooling liquid flow path. The sealing member is composed of a linear member. The linear member is clamped on the object interface in a state that the linear member is bent into a ring shape along the guide ring and two end parts of the linear member are in contact with each other.

Description

Technical Field

[0001] The technology disclosed in this specification relates to electric motors. Background Art

[0002] The electric motor disclosed in Japanese Patent Application Laid-Open No. 2017-204980 includes a housing, a stator core, and a guide ring. The stator core and the guide ring are housed in a cylindrical housing. The guide ring has a base portion connected to the end face of the stator core, and an annular protrusion extending radially outward from the base. The outer peripheral surface of the stator core and the outer peripheral surface of the annular protrusion are connected to the inner peripheral surface of the housing. An annular coolant flow path is formed by the space surrounded by the stator core, the guide ring, and the housing. The electric motor is cooled by supplying coolant (e.g., oil) from the annular coolant flow path to various parts in the housing. Summary of the Invention

[0003] In the electric motor disclosed in Japanese Patent Application Laid-Open No. 2017-204980, the outer circumferential surface of the guide ring (i.e., the outer circumferential surface of the annular protrusion) contacts the inner circumferential surface of the housing. Therefore, if the diameters and roundness of the inner circumferential surface of the housing and the outer circumferential surface of the guide ring are not accurate, a gap will form between the housing and the guide ring. If a gap forms between the housing and the guide ring, coolant in the annular coolant flow path will leak. This specification proposes a technology that can suppress coolant leakage in the annular coolant flow path.

[0004] The first type of electric motor disclosed in this specification has a stator core, a housing, a guide ring and a sealing member. The housing accommodates the stator core. The housing has an opposing portion opposite to an end face of the stator core. The guide ring is accommodated in the housing, has an annular shape extending around the motor shaft, and is clamped between the end face and the opposing portion. The sealing member is arranged at an object interface, and the object interface is at least one of an interface between the guide ring and the end face and an interface between the guide ring and the opposing portion. A circular annular coolant flow path is formed by the space surrounded by the inner surface of the housing, the outer peripheral surface of the guide ring and the end face. The sealing member is composed of a linear member. The linear member is clamped at the object interface in a state where it is bent into a ring shape along the guide ring so that its two ends are in contact with each other.

[0005] In this electric motor, a guide ring is sandwiched between the end face of the stator core and the opposite face of the housing. Thus, the interface between the guide ring and the end face of the stator core and the interface between the guide ring and the opposite face of the housing serve as sealing surfaces constituting an annular coolant flow path. Since a sealing member is provided at the object interface, which is at least one of these interfaces, leakage of the coolant at the object interface can be suppressed. In addition, the sealing member is composed of a linear member. The linear member is clamped at the object interface by being bent into an annular shape along the guide ring so that its two ends are in contact with each other, thereby sealing the annular object interface. Since the linear member can be continuously formed by extrusion molding, it can be manufactured more efficiently than a sealing member (for example, an O-ring, etc.) that is pre-formed into an annular shape. Thus, the linear member can be manufactured at a lower cost than a sealing member that is pre-formed into an annular shape. Therefore, this electric motor can be manufactured at a low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will be described below with reference to the accompanying drawings, in which like reference numerals represent like parts, and in which:

[0007] Figure 1 It is an exploded perspective view of the electric motor of the embodiment.

[0008] Figure 2 It is a cross-sectional view of the electric motor of the embodiment.

[0009] Figure 3 It is a plan view of the stator along the axial direction.

[0010] Figure 4 It is an enlarged cross-sectional view of the guide ring and its surroundings.

[0011] Figure 5 It is a plan view of the guide ring along the axial direction.

[0012] Figure 6 yes Figure 5 An enlarged view of the groove in range X (the lower part of the guide ring).

[0013] Figure 7 yes Figure 5 An enlarged view of the groove and sealing component in range X (the lower part of the guide ring).

[0014] Figure 8 It is a three-dimensional diagram of the stator core.

[0015] Figure 9 It is an enlarged view of the wide portion 71w of the modification.

[0016] Figure 10 This is a plan view of the guide ring of the modified example as viewed along the axial direction.

[0017] Figure 11 It is an enlarged view of the joining portion between both front end surfaces of a sealing member according to a modified example. DETAILED DESCRIPTION

[0018] The electric motor disclosed in this specification may also have the following structure.

[0019] (Method 2)

[0020] In the electric motor according to aspect 1, the linear member includes a stacked portion in which both end portions overlap in a radial direction of the guide ring.

[0021] (Method 3)

[0022] The electric motor as described in Mode 2,

[0023] An annular groove is provided on the surface of the guide ring constituting the object interface.

[0024] The linear member is arranged in the annular groove,

[0025] The annular groove has a narrow portion and a wide portion, wherein the wide portion is wider than the narrow portion.

[0026] The stacked portion is disposed within the wide portion.

[0027] (Aspect 4) In the electric motor according to aspect 1, one front end surface and the other front end surface of the linear member are bonded or welded to each other.

[0028] (Mode 5) The electric motor according to any one of Modes 1 to 4,

[0029] The sealing member is arranged to be inclined relative to the horizontal plane.

[0030] A portion where the two ends of the linear member are in contact with each other is arranged in a range including the lowermost portion of the sealing member.

[0031] (Mode 6) The electric motor according to any one of Modes 1 to 5,

[0032] Cooling liquid is stored in the housing.

[0033] A portion where the two ends of the linear member are in contact with each other is arranged below a water level of the coolant in the housing.

[0034] (Aspect 7) In the electric motor according to any one of aspects 1 to 6, an in-core coolant flow path is provided inside the stator core, and the coolant supplied from the annular coolant flow path flows through the in-core coolant flow path.

[0035] (Mode 8) The electric motor according to any one of Modes 1 to 7,

[0036] The coil end is arranged on the inner circumference side of the guide ring.

[0037] The guide ring is provided with a coolant discharge flow path that penetrates the guide ring in the radial direction.

[0038] In any of the aspects 2 to 4, leakage of the coolant from the contact portions of the both end portions of the linear member can be suppressed.

[0039] In embodiment 5, the sealing member is arranged at an inclination relative to the horizontal plane. In other words, the central axis of the annular sealing member is inclined relative to the vertical axis. With this structure, coolant tends to accumulate around the lowest portion of the sealing member, thus preventing leakage from the contact areas of the linear members caused by the accumulated coolant.

[0040] According to the sixth aspect, leakage of the coolant from the contact portions between the two end portions of the linear member caused by the coolant accumulated in the housing can be suppressed.

[0041] In either of Modes 7 and 8, the electric motor can also be cooled efficiently.

[0042] Figure 1 、 2 The motor 10 of the illustrated embodiment includes a rotor 20, a stator 30, and a housing 50. The rotor 20 includes a shaft 24. The stator 30 has a cylindrical shape. The rotor 20 is disposed within the center hole of the stator 30 so that the central axis of the shaft 24 coincides with the central axis of the stator 30. The rotor 20 and the stator 30 are housed within the housing 50. Hereinafter, the direction parallel to the rotation axis of the motor 10 (i.e., the central axis of the shaft 24) is referred to as the axial direction, the direction along the radius of a circle centered on the rotation axis of the motor 10 is referred to as the radial direction, and the direction along the circle is referred to as the circumferential direction. In the present embodiment, the rotation axis of the motor 10 is disposed horizontally.

[0043] The housing 50 includes an outer peripheral wall 52 and a partition wall 54. The outer peripheral wall 52 has a cylindrical or box-like shape. The partition wall 54 is provided at one axial end of the outer peripheral wall 52. A through hole 54a is provided at the center of the partition wall 54.

[0044] The stator 30 has a stator core 32 and a coil 40. Figure 2, the coil ends 42a and 42b of the coil 40 are simplified. The stator core 32 has a cylindrical shape. The coil 40 is wound around the stator core 32 (more specifically, the teeth 34 to be described later). The stator core 32 has an end face 32a, an end face 32b, and an outer peripheral surface 32c. The end face 32a is an end face in the axial direction of the stator core 32, and the end face 32b is an end face on the opposite side of the end face 32a. The coil end 42a is provided on the end face 32a. The coil end 42b is provided on the end face 32b. The coil ends 42a and 42b are the bent portions of the coil 40 wound around the stator core 32. The coil end 42a protrudes from the end face 32a, and the coil end 42b protrudes from the end face 32b. As shown Figure 3 As shown, coil ends 42a are distributed in a ring shape on end surface 32a. Similarly, coil ends 42b are distributed in a ring shape on end surface 32b.

[0045] like Figure 1 、 2 As shown, the inner surface 52a of the outer peripheral wall 52 of the housing 50 has a cylindrical shape extending along the outer peripheral surface 32c of the stator core 32. The inner surface 52a of the outer peripheral wall 52 faces the outer peripheral surface 32c of the stator core 32. The partition wall 54 of the housing 50 faces the end surface 32a of the stator core 32. The partition wall 54 is an example of a facing portion. Figure 2 As shown, a gap is provided between the partition wall 54 and the end face 32a of the stator core 32, and the coil end 42a is arranged in the gap. Figure 1 As shown, the outer circumferential surface 32c of the stator core 32 is provided with a plurality of protrusions 38. Furthermore, the inner surface 52a of the outer circumferential wall 52 is provided with a plurality of recesses 58. The stator core 32 is housed within the housing 50 such that each protrusion 38 is disposed within a corresponding recess 58. Each protrusion 38 is provided with a bolt fastening hole extending in the axial direction. Bolts 49 are inserted through each bolt fastening hole. The stator core 32 is fastened to the housing 50 by the bolts 49.

[0046] The rotor 20 is disposed concentrically with the stator core 32 in the center hole of the stator core 32. The shaft 24 of the rotor 20 is inserted through the through hole 54a of the housing 50. The rotor 20 is rotatably supported in the housing 50 by bearings or the like.

[0047] like Figure 1 、 2As shown, the motor 10 includes a guide ring 60. The guide ring 60 has an annular shape. The guide ring 60 is housed in the housing 50. The guide ring 60 is arranged to extend annularly around the rotation axis of the motor 10 (i.e., the shaft 24). The guide ring 60 is arranged concentrically with the rotor 20 and the stator core 32, between the end face 32a of the stator coil 32 and the partition wall 54 of the housing 50. The guide ring 60 is clamped and fixed between the end face 32a and the partition wall 54. The coil end 42a is arranged radially inward of the guide ring 60. The guide ring 60 divides the space between the stator core 32 and the partition wall 54 into an outer peripheral space 56 and an inner peripheral space 57. The outer peripheral space 56 is a space enclosed by the inner surface of the housing 50, the outer peripheral surface of the guide ring 60, and the end face 32a, and has an annular shape. Hereinafter, the outer peripheral space 56 is referred to as the annular coolant flow path 56.

[0048] like Figure 4 As shown, the guide ring 60 has end faces 60a and 60b on both sides in the axial direction. The end face 60a of the guide ring 60 contacts the end face 32a of the stator core 32. A groove 71 is provided in the end face 60a. The groove 71 extends annularly along the guide ring 60. A sealing member 66 is provided in the groove 71. The sealing member 66 is fixed in the groove 71 by being clamped and pressurized by the stator core 32 and the guide ring 60. The sealing member 66 seals the interface (i.e., the contact surface) between the guide ring 60 and the stator core 32.

[0049] Figure 5 71 along the axial direction. Figure 5 As shown, the groove 71 extends annularly along the guide ring 60 at the end surface 60a of the guide ring 60. Figure 6 As shown, the groove 71 has a wide portion 71w and a narrow portion 71n. The width of the groove 71 is wider in the wide portion 71w than in the narrow portion 71n. The wide portion 71w is arranged at a position including the lowest part of the groove 71. The portion of the groove 71 other than the wide portion 71w is composed of the narrow portion 71n. The sealing member 66 is composed of a rubber linear member. Figure 5 As shown, the linear member is a linear member extending from the front end face 66c to the front end face 66d. The linear member is formed into a circular ring shape by being embedded in the groove 71. The sealing member 66 is composed of a circular ring-shaped linear member. The sealing member 66 is configured so that its central axis is consistent with the rotation axis of the motor 10. Therefore, the sealing member 66 is configured vertically relative to the horizontal plane. Figure 7As shown, the portion of the linear member near the front end face 66c (hereinafter referred to as end face 66a) and the portion near the front end face 66d (hereinafter referred to as end face 66b) radially overlap within the wide portion 71w. Ends 66a and 66b are radially compressed by being clamped between the two side surfaces of wide portion 71w. As a result, end portions 66a and 66b are in close contact with each other. The overlapping portion of end portions 66a and 66b is located at the bottom of sealing member 66.

[0050] like Figure 4 As shown, the end face 66b of the guide ring 60 contacts the inner surface of the partition wall 54 of the housing 50. A groove 72 is provided on the end face 60b. The groove 72 extends annularly along the guide ring 60. A sealing member 68 is provided within the groove 72. The sealing member 68 is held and pressurized by the partition wall 54 and the guide ring 60, thereby being secured within the groove 72. The sealing member 68 seals the interface (i.e., the contact surface) between the guide ring 60 and the partition wall 54.

[0051] The sealing member 68 and the groove 72 are Figures 5 to 7 The sealing member 66 and the groove 71 shown are similarly arranged. Figures 5 to 7 In FIG. 1 , the reference numerals corresponding to the sealing member 68 and the groove 72 are indicated in parentheses. Figure 5 As shown, the groove 72 extends annularly along the guide ring 60 at the end surface 60b of the guide ring 60. Figure 6 As shown, the groove 72 has a wide portion 72w and a narrow portion 72n. The width of the groove 72 is wider in the wide portion 72w than in the narrow portion 72n. The wide portion 72w is arranged at a position including the lowest part of the groove 72. The portion of the groove 72 other than the wide portion 72w is composed of the narrow portion 72n. The sealing member 68 is composed of a linear member made of rubber. Figure 5 As shown, the linear member is a linear member extending from the front end face 68c to the front end face 68d. The linear member is formed into a circular ring shape by being embedded in the groove 72. The sealing member 68 is composed of a circular ring-shaped linear member. The sealing member 68 is configured so that its central axis is consistent with the rotation axis of the motor 10. Therefore, the sealing member 68 is configured vertically relative to the horizontal plane. Figure 7 As shown, the portion of the linear member near the front end face 68c (hereinafter referred to as end 68a) and the portion near the front end face 68d (hereinafter referred to as end 68b) radially overlap within the wide portion 72w. Ends 68a and 68b are clamped radially by the two side surfaces of wide portion 72w. As a result, ends 68a and 68b are in close contact with each other. The overlapping portion of ends 68a and 68b is located at the bottom of sealing member 68.

[0052] like Figure 4As shown, a stepped portion 59 is provided on the inner surface 52a of the housing 50. The stepped portion 59 is provided over the entire circumferential area. The end face 32a of the stator core 32 is axially in contact with the stepped portion 59. The end face 32a is in close contact with the stepped portion 59. Alternatively, a sealing member (e.g., an O-ring, metal gasket, liquid gasket, etc.) may be provided at the interface between the end face 32a and the stepped portion 59.

[0053] The housing 50 is provided with a cooling liquid supply passage 53a. The cooling liquid supply passage 53a connects the outside of the housing 50 with the annular cooling liquid flow path 56. Figure 2 As shown, a coolant discharge passage 53b is provided at the lower part of the housing 50. The coolant discharge passage 53b connects the inside and outside of the housing 50. The coolant discharge passage 53b is connected to the coolant supply passage 53a via a circulation flow path (not shown) provided on the outside of the housing 50. A pump (not shown) is provided in the circulation flow path. In addition, coolant is stored inside the housing 50. Through the action of the pump, the coolant in the housing 50 is supplied to the annular coolant flow path 56 via the coolant discharge passage 53b and the coolant supply passage 53a. The coolant supplied to the annular coolant flow path 56 is discharged to the inside of the housing 50, which will be described in detail later. In this way, the coolant circulates in the circulation flow path and the housing 50. In this embodiment, the coolant is cooling oil. The cooling oil acts as a coolant for cooling the electric motor 10 and also acts as a lubricating oil for lubricating the rotor 20.

[0054] like Figure 1 As shown, a plurality of coolant discharge passages 62 are provided on the guide ring 60. Figure 4 As shown, each coolant discharge flow path 62 penetrates the guide ring 60 in the radial direction. Figure 1 As shown, a plurality of coolant discharge passages 62 are provided in the guide ring 60 in a circumferentially dispersed manner. Figure 4 As shown, the annular coolant flow path 56 and the space 57 (ie, the space where the coil end 42a is located) are connected by coolant discharge flow paths 62. Each coolant discharge flow path 62 discharges the coolant in the annular coolant flow path 56 toward the coil end 42a.

[0055] like Figure 8 As shown, the stator core 32 is composed of a plurality of electromagnetic steel plates 36 stacked in the axial direction. The stator core 32 has a back yoke 33 and a plurality of teeth 34. The back yoke 33 has a cylindrical shape. Each tooth 34 protrudes from the inner circumferential surface of the back yoke 33. That is, each tooth 34 protrudes radially inward from the back yoke 33. Each tooth 34 extends in the axial direction. The plurality of teeth 34 are arranged at intervals in the circumferential direction. The coil 40 is wound around the teeth 34. Each tooth 34 is located radially inward of the guide ring 60. Thus, as shown in FIG. Figure 3As shown, the coil end portion 42 a is arranged radially inward of the guide ring 60 .

[0056] like Figure 2 As shown, multiple in-core coolant flow paths 39 are provided within the stator core 32. Each in-core coolant flow path 39 extends axially. One end of each in-core coolant flow path 39 opens at the end surface 32a and connects to the annular coolant flow path 56. The other end of each in-core coolant flow path 39 opens at the end surface 32b. The multiple in-core coolant flow paths 39 are distributed circumferentially.

[0057] When the electric motor 10 is operating, coolant is supplied from the coolant supply passage 53a to the annular coolant flow path 56. Coolant in the annular coolant flow path 56 flows into the coolant discharge passage 62 and the in-core coolant flow path 39. Coolant in the coolant discharge passage 62 is discharged toward the coil end 42a. This cools the coil end 42a. The coolant discharged toward the coil end 42a flows toward the lower portion of the housing 50. Furthermore, the coolant flowing through the in-core coolant flow path 39 cools the stator core 32. The coolant in the in-core coolant flow path 39 is discharged from the end surface 32b into the housing 50. The coolant discharged from the end surface 32b cools the coil end 42b. The coolant discharged from the end surface 32b flows toward the lower portion of the housing 50. The coolant that has flowed toward the lower portion of the housing 50 and remains there is pumped from the coolant discharge passage 53b to the coolant supply passage 53a via an external pump. In this manner, the motor 10 is cooled by the circulation of the coolant.

[0058] In the electric motor 10, the guide ring 60 is axially sandwiched between the housing 50 and the stator core 32. This structure allows pressure to be applied to the interfaces between the guide ring 60 and the housing 50, as well as the interfaces between the guide ring 60 and the stator core 32. By appropriately applying pressure to the sealing members 66 and 68, these interfaces can be properly sealed. This prevents coolant leakage at each interface and accurately controls the coolant flow rate within each flow path.

[0059] In addition, the sealing members 66 and 68 are composed of linear members bent into a ring shape along the guide ring 60. The linear members can be manufactured efficiently by extrusion molding or the like, and can be manufactured at a low cost. Therefore, by using the linear members as sealing members, the manufacturing cost of the motor 10 can be reduced. In addition, in the manufacturing process of the motor 10, the sealing members 66 and 68 can be set in the following manner. First, the linear members are prepared by cutting a very long linear rubber member wound on a reel or the like into a specified length. Secondly, the linear members are inserted into the grooves 71 and 72 so as to form a circular ring shape. Next, the guide ring 60 and the stator core 32 are assembled into the housing 50 in such a manner that the guide ring 60 is clamped by the partition wall 54 and the stator core 32. Thus, the sealing members 66 and 68 can be properly set in the housing 50.

[0060] In addition, in the sealing members 66 and 68, the ends of the linear members are stacked in the radial direction and are in close contact with each other. Therefore, it is possible to suppress the leakage of the coolant from the stacked parts at the two ends. In addition, in order to further improve the sealing performance of the stacked parts at the two ends, as shown in FIG. Figure 9 As shown, protrusions 80 may be provided on the side surfaces of the wide portion.

[0061] Figure 5 The dotted line 100 represents the liquid level of the coolant retained in the housing 50 during the operation of the motor 10. Figure 5 As shown, the lowest portions of the guide ring 60 and sealing members 66 and 68 are located below the coolant level 100. Therefore, the stacked portions at both ends of the linear members are immersed in the coolant. Consequently, the coolant is less likely to leak from the stacked portions at both ends.

[0062] In addition, Figure 5 In the embodiment, the stacked portion of the linear members is arranged at the lowest part of the sealing members 66 and 68. However, as long as the stacked portion is arranged below the liquid level 100, the leakage of the coolant at the stacked portion can be suppressed regardless of the stacked portion's position. Figure 10 As shown, the stacked portion of the linear members may be arranged at a position excluding the lowermost portion of the sealing members 66 and 68 .

[0063] In addition, in the above embodiment, both ends of the linear member are stacked in the radial direction. Figure 11 As shown, the front end surfaces 66c and 66d on both sides of the linear member can also be welded or bonded to each other. In this structure, the annular sealing member can also be formed by using the linear member.

[0064] The above detailed descriptions of the embodiments are provided, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various variations and modifications of the specific examples illustrated above. The technical elements described in this specification or the drawings may be technically useful alone or in various combinations, and are not limited to the combinations described in the claims at the time of application. In addition, the technology illustrated in this specification or the drawings may achieve multiple objectives simultaneously, and achieving one of these objectives alone is technically useful.

Claims

1. An electric motor, wherein: have: stator core; a housing for accommodating the stator core and having an opposing portion opposing one end surface of the stator core; a guide ring housed in the housing, having an annular shape extending around the motor shaft and sandwiched between the end surface and the opposing portion; and a sealing member provided at an interface with an object, the interface with the object being at least one of an interface between the guide ring and the end surface and an interface between the guide ring and the opposing portion; The space enclosed by the inner surface of the shell, the outer peripheral surface of the guide ring and the end surface forms an annular coolant flow path. The sealing member is composed of a linear member, The linear member is bent into a ring shape along the guide ring so that both ends thereof are in contact with each other and is clamped by the counterpart interface.

2. The electric motor according to claim 1, wherein The linear member includes a stacked portion in which both end portions overlap in the radial direction of the guide ring.

3. The electric motor according to claim 2, wherein An annular groove is provided on the surface of the guide ring constituting the object interface. The linear member is arranged in the annular groove, The annular groove has a narrow portion and a wide portion, wherein the wide portion is wider than the narrow portion. The stacked portion is disposed within the wide portion.

4. The electric motor according to claim 1, wherein One front end surface and the other front end surface of the linear member are bonded or welded to each other.

5. The electric motor according to any one of claims 1 to 4, wherein The sealing member is arranged to be inclined relative to the horizontal plane. A portion where the two ends of the linear member are in contact with each other is arranged in a range including the lowermost portion of the sealing member.

6. The electric motor according to any one of claims 1 to 4, wherein: Cooling liquid is stored in the housing. A portion where the two ends of the linear member are in contact with each other is arranged below a water level of the coolant in the housing.

7. The electric motor according to any one of claims 1 to 4, wherein An in-core coolant flow path is provided inside the stator core, and the coolant supplied from the annular coolant flow path flows through the in-core coolant flow path.

8. The electric motor according to any one of claims 1 to 4, wherein The coil end is arranged on the inner circumference side of the guide ring. The guide ring is provided with a coolant discharge flow path that penetrates the guide ring in the radial direction.

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