Stator fixing structure and electric pump

Abstract

Improve the ease of assembly of the stator. [Solution] The fixing structure for the stator 21 comprises a stator 21 and a housing body portion 41 that houses the stator 21. The stator 21 has an annular stator core 22, an insulator 24 attached to the stator core 22, and a coil 23 wound around the stator core 22 via the insulator 24. The housing body portion 41 and the insulator 24 each have a first bottom surface 43b and a back surface 24b of the flange portion 24a that face each other in the axial direction. The housing body portion 41 has a projection P protruding from the first bottom surface 43b, and the insulator 24 has a hole H that opens on the back surface 24b through which the projection P is inserted. The insulator 24 of the stator 21 is fixed to the housing body portion 41 by the projection P which is crimped while inserted through the hole H.

Description

Technical Field

[0001] The present invention relates to a stator fixing structure and an electric pump.

Background Art

[0002] Patent Document 1 discloses an electric oil pump in which the outer peripheral surface of a stator portion is fixed to the inner peripheral surface of a pump housing by shrink fitting. Patent Document 2 discloses an electric oil pump device in which a stator is fixed by screwing a bolt inserted through a pump housing from a pump plate into a nut embedded in an insulator.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the assembly of the stator by shrink fitting, it takes time to heat the parts. Also, in the assembly of the stator by bolt fixing, the number of parts increases by the number of bolts, and the assembly property deteriorates.

[0005] The present invention has been made in view of such problems, and an object thereof is to improve the assembly property of the stator.

Means for Solving the Problems

[0006] The present invention relates to a stator fixing structure comprising a stator and a housing for housing the stator, wherein the stator has an annular stator core, an insulator attached to the stator core, and a coil wound around the stator core via the insulator, the housing and the insulator each have a first opposing surface and a second opposing surface that face each other in the axial direction, the housing has a projection protruding from the first opposing surface, the insulator has a hole opening in the second opposing surface through which the projection is inserted, and the stator insulator is fixed to the housing by a projection that is crimped while inserted through the hole.

[0007] According to this invention, the stator can be fixed to the housing simply by inserting the projection through the hole and crimping it, thereby improving the ease of assembling the stator.

[0008] Furthermore, the present invention is characterized in that the housing has a stepped portion to which the stator core abuts and is positioned in the axial direction.

[0009] According to this invention, the stator can be precisely positioned in the axial direction.

[0010] Furthermore, the present invention is characterized in that the insulator has a deformable portion that extends in a groove-like manner along the circumferential direction, located radially inward from the hole.

[0011] According to this invention, when the stator core is positioned on a stepped portion and the projection is not crimped, the deformation that occurs in the insulator when the projection is crimped, caused by the gap between the first opposing surface of the housing and the second opposing surface of the insulator, can be absorbed by the deformed portion, thereby suppressing the load on the insulator and thus suppressing a decrease in the durability of the insulator.

[0012] Furthermore, the present invention is characterized in that the first opposing surface of the housing and the second opposing surface of the insulator come into contact with each other to form a positioning section that positions the stator axially relative to the housing.

[0013] According to this invention, the stator can be positioned in the axial direction simply by machining the first opposing surface of the housing that faces the insulator so that the first opposing surface also serves as the positioning surface, thus reducing the amount of machined surface.

[0014] Furthermore, in this invention, the insulator has a flange portion having a second opposing surface, and the flange portion is sandwiched between a crimped projection and a housing.

[0015] According to this invention, the stator can be precisely positioned in the axial direction.

[0016] Furthermore, the present invention is characterized in that it has multiple fixing points in which projections are crimped while inserted into holes, and at least two or more fixing points the projections abut against the inner surface of the holes by the crimped and deformed portions.

[0017] According to this invention, the stator is positioned radially by projections crimped at at least two or more fixed points, thereby easing the need for positioning within the inner circumference of the housing.

[0018] Furthermore, the present invention relates to an electric pump having a stator fixing structure, comprising a pump section for discharging liquid and a motor section for driving the pump section by rotating a drive shaft, wherein the motor section has a stator, and the housing accommodates the pump section and the motor section.

[0019] This invention makes it possible to improve the ease of assembly of the stator in an electric pump in which the pump section and the motor section are integrally incorporated. [Effects of the Invention]

[0020] These inventions improve the ease of assembly of the stator. [Brief explanation of the drawing]

[0021] [Figure 1]This is a schematic configuration diagram of an electric pump according to an embodiment of the present invention. [Figure 2] This is a top view showing the electric pump according to an embodiment of the present invention with the cover removed. [Figure 3] This is a diagram showing a main part of the electric pump according to an embodiment of the present invention. [Figure 4] This is a diagram showing the state before the protrusion is caulked. [Figure 5] This is a diagram showing a first modification example of the insulator. [Figure 6] This is a diagram showing a second modification example of the insulator. [Figure 7] This is a diagram showing a modification example of the axial positioning of the stator. [Figure 8] This is a diagram showing a modification example of the radial positioning of the stator.

Mode for Carrying Out the Invention

[0022] Hereinafter, the electric pump 100 according to an embodiment of the present invention will be described with reference to the accompanying drawings.

[0023] The electric pump 100 is mounted on a vehicle and is used as a pump for discharging a coolant (liquid) for cooling a traveling motor mounted on the vehicle or a pump for discharging an oil (liquid) for lubricating a gear mounted on the vehicle. The electric pump 100 may be used as a fluid pressure supply source for discharging a working fluid (liquid) for driving a device, and may be mounted on industrial machinery other than vehicles.

[0024] <于 As shown in FIG. 1, the electric pump 100 includes a pump unit 10 that discharges a liquid, a motor unit 20 that rotates a drive shaft 1 to drive the pump unit 10, a control unit 30 that controls the motor unit 20, and a housing 40 that houses the pump unit 10, the motor unit 20, and the control unit 30. In the electric pump 100, the control unit 30, the motor unit 20, and the pump unit 10 are arranged in this order from the upper side in FIG. 1. Hereinafter, the axial direction, the radial direction, and the circumferential direction of the drive shaft 1 will also be simply referred to as the "axial direction", the "radial direction", and the "circumferential direction".

[0025] The pump section 10 is an internal gear pump and includes an inner rotor 12 through which the drive shaft 1 is inserted and connected, and an outer rotor 13 provided outside the inner rotor 12. The inner rotor 12 and outer rotor 13 are housed in the housing body 41 of the housing 40, are eccentrically positioned relative to each other, and are covered by the pump cover 56 of the housing 40. The center of the inner rotor 12 is coaxially positioned so as to overlap with the drive shaft 1, while the center of the outer rotor 13 is offset from the drive shaft 1. The inner rotor 12 has multiple external teeth (not shown), and the outer rotor 13 has multiple internal teeth (not shown) that slide against the external teeth. The number of teeth of the external teeth and internal teeth are different, and the pump chamber 14 is partitioned by adjacent external teeth of the inner rotor 12 and internal teeth of the outer rotor 13. Multiple pump chambers 14 are formed in the pump section 10.

[0026] The motor unit 20 includes an annular stator 21 and a motor rotor 25 positioned radially inward of the stator 21. The motor unit 20 is an electric motor, and the drive shaft 1 also serves as the rotation axis of the motor unit 20 as an electric motor. The axial, radial, and circumferential directions of the drive shaft 1 correspond to the axial, radial, and circumferential directions of the fixing structure of the stator 21, which will be described later.

[0027] The stator 21 has an annular stator core 22 installed so as to surround the motor rotor 25, and coils 23 wound around the stator core 22. The stator core 22 is constructed by laminating multiple electromagnetic steel sheets. The stator core 22 has U-phase coils, V-phase coils, and W-phase coils formed as coils 23, corresponding to the three-phase drive currents, and the ends of the coil wiring extending from the coils 23 are connected to the control unit 30.

[0028] The motor rotor 25 has a rotor core 26 connected to the outer circumferential surface of the drive shaft 1 and rotating together with the drive shaft 1, and a plurality of permanent magnets (not shown) provided on the rotor core 26, and is press-fitted onto the drive shaft 1. The motor rotor 25 is press-fitted from the base end 1b side (upper side in Figure 1) of the drive shaft 1 while receiving a press-fitting load at the tip 1a of the drive shaft 1, until it is press-fitted up to the flange 1c of the drive shaft 1, which serves as the press-fitting end.

[0029] The control unit 30 includes an electronic component 31, a substrate 32 on which the electronic component 31 is mounted and to which the coil 23 of the motor unit 20 is connected, and a heat dissipation unit 33 for dissipating heat from the substrate 32, and controls the current supplied to the stator 21 to drive the motor unit 20.

[0030] The housing 40 comprises a housing body 41 made of a metal material (for example, an aluminum alloy or a steel material) and having an opening 42, a cover 51 that covers the opening 42, and a pump cover 56 that covers the pump unit 10.

[0031] The housing body 41 includes a motor housing recess 43 that houses the motor unit 20, a through hole 44 through which the drive shaft 1 is inserted, an oil seal housing recess 46 formed axially continuous with the through hole 44 and housing the oil seal 65, and a pump housing recess 47 that houses the pump unit 10.

[0032] The motor housing recess 43 includes a first housing recess 43a with an opening 42 formed therein, and a second housing recess 43c that extends axially from the first bottom surface 43b of the first housing recess 43a toward the opposite side of the opening 42 (lower side in Figure 1) and forms an annular space. The outer surface of the stator core 22 abuts against the inner surface of the second housing recess 43c by a spigot fitting, thereby positioning the stator 21 radially through the radial positioning of the stator core 22.

[0033] The insertion hole 44 and the oil seal housing recess 46 are formed in a cylindrical portion 43e that protrudes axially from the center of the second bottom surface 43d of the second housing recess 43c, and the pump housing recess 47 is formed in the housing body portion 41 in the axial direction on the side opposite to the opening 42 from the second bottom surface 43d (lower side in Figure 1).

[0034] The through hole 44 extends axially and communicates with the oil seal housing recess 46 on the side of the opening 42 (upper side in Figure 1), and with the pump housing recess 47 on the opposite side of the opening 42 (lower side in Figure 1). The oil seal housing recess 46 is formed to be larger in diameter than the through hole 44 and opens to the tip surface of the cylindrical portion 43e. The pump housing recess 47 houses the inner rotor 12 and the outer rotor 13, and the center of the pump housing recess 47 is formed offset from the center of the through hole 44.

[0035] The cover 51 is fixed to the housing body 41 by fastening members (not shown) and houses the control unit 30. The pump cover 56 is fixed to the housing body 41 by fastening members (not shown) and covers the pump housing recess 47. The pump cover 56 has a shaft housing portion 56a that houses the tip portion 1a of the drive shaft 1, and the tip portion 1a housed in the shaft housing portion 56a is positioned so as not to come into contact with the pump cover 56.

[0036] The drive shaft 1 has a large-diameter portion 2 and a small-diameter portion 3 which is smaller in diameter than the large-diameter portion 2. The small-diameter portion 3 is formed on the tip end 1a side (lower side in Figure 1), and the large-diameter portion 2 is formed on the base end 1b side (upper side in Figure 1). A magnet 67 is provided at the base end 1b so as not to come into contact with the electronic components 31 and substrate 32 of the control unit 30. Changes in magnetism caused by the magnet 67 are detected by the control unit 30 and used to calculate the rotation angle and rotation speed of the drive shaft 1. The flange portion 1c is formed on the large-diameter portion 2 on the base end 1b side (upper side in Figure 1) of the oil seal 65.

[0037] An oil seal 65 and a plurality of bushings 60 slide against the outer circumferential surface of the large-diameter portion 2. The plurality of bushings 60 are provided between the inner circumferential surface of the insertion hole 44 and the outer circumferential surface of the large-diameter portion 2, and rotatably support the drive shaft 1 relative to the housing body portion 41. Note that only one bushing 60 may be provided. Alternatively, the drive shaft 1 may be rotatably supported by a bearing (for example, a ball bearing) instead of the bushings 60. The bearing can be provided between the flange portion 1c and the motor rotor 25 in the axial direction. The small-diameter portion 3 is inserted into the insertion hole 12a of the inner rotor 12. The small-diameter portion 3 has a flat portion 3a that forms a two-sided width, and the flat portion 3a is in surface contact with the insertion hole 12a.

[0038] In the electric pump 100 configured in this way, under the control of the control unit 30, the motor rotor 25 of the motor unit 20 rotates integrally with the drive shaft 1, thereby transmitting the rotational torque of the drive shaft 1 to the inner rotor 12 and driving the pump unit 10. In the pump unit 10, the outer teeth of the inner rotor 12 slide against the inner teeth of the outer rotor 13, causing the inner rotor 12 and outer rotor 13 to rotate, and consequently the pump chamber 14 to repeatedly expand and contract. In the expanded region (suction region) where the pump chamber 14 expands, liquid is drawn in through the suction port (not shown) formed in the pump cover 56, and in the contracted region (discharge region) where the pump chamber 14 contracts, liquid is discharged to the outside through the discharge port (not shown) formed in the pump cover 56.

[0039] As shown in Figures 1 and 2, the stator 21 further includes an insulator 24 that insulates the stator core 22 from the coil 23. The insulator 24 has a cylindrical shape and is made of resin. The insulator 24 is mounted on the stator core 22 from the axial direction, and the coil 23 is wound around the stator core 22 via the insulator 24 by being wound around the stator core 22 with the insulator 24 mounted. The coil 23 is wound around multiple teeth of the stator core 22 that extend radially inward.

[0040] As shown in Figures 1-3, the insulator 24 has a flange portion 24a on the side of the opening 42 of the housing body 41 (upper side in Figure 1). The flange portion 24a has a back surface 24b that faces the first bottom surface 43b of the first receiving recess 43a of the housing body 41 in the axial direction. Therefore, the housing body 41 and the insulator 24 each have a first facing surface, the first bottom surface 43b, and a second facing surface, the back surface 24b, respectively, that face each other in the axial direction.

[0041] The housing body portion 41 has a projection P that protrudes from the first bottom surface 43b. As shown in Figure 4, the projection P is formed in a cylindrical shape before crimping and protrudes axially from the first bottom surface 43b. A conical recess D is formed on the tip surface of the projection P before crimping, and the periphery of the recess D is plastically deformed by crimping and pressed against the fixing surface H3 of the hole H. Crimping can be performed, for example, by a crimping machine that applies pressure and deforms the periphery of the recess D so as to push it outward via a jig.

[0042] The insulator 24 has a hole H that opens on the back surface 24b of the flange portion 24a and through which the projection P is inserted. The hole H is formed in a cylindrical boss 24c provided on the flange portion 24a and has a fixing surface H3, a small diameter portion H1 that opens on the back surface 24b, and a large diameter portion H2 that has a larger inner diameter than the small diameter portion H1. The small diameter portion H1 is formed as a hole for inserting the projection P, and the large diameter portion H2 opens on the tip surface of the boss 24c. The fixing surface H3 is a stepped portion formed on the inner surface of the hole H and is connected to the inner surfaces of the small diameter portion H1 and the large diameter portion H2, respectively. A space is formed between the large diameter portion H2 and the projection P to accommodate the portion of the projection P that deforms due to crimping.

[0043] As shown in Figure 3, the insulator 24 is fixed to the housing body 41 by a projection P that is crimped while inserted through the hole H. The peripheral portion of the recess D in the projection P is deformed by the crimping and pressed against the fixing surface H3, thereby fixing the insulator 24 to the housing body 41 while pressed against the first bottom surface 43b. The first bottom surface 43b is a machined surface, and by making the first bottom surface 43b a machined surface, the adhesion with the insulator 24 is improved.

[0044] As shown in Figure 1, the housing body 41 further has a stepped portion 48 against which the stator core 22 abuts and is positioned in the axial direction. The stepped portion 48 is formed along the circumferential direction on the inner circumferential surface of the second housing recess 43c, and the outer circumferential end of the stator core 22 abuts against the stepped portion 48. The stepped portion 48 is formed around the entire inner circumferential surface of the second housing recess 43c, and the stator 21 is positioned in the axial direction by positioning the stator core 22 with the stepped portion 48.

[0045] As shown in Figure 2, the flange portion 24a is formed in a generally annular shape when viewed from the axial direction, and the electric pump 100 has multiple fixing points F in which the projections P of the housing body portion 41 are inserted into the holes H of the insulator 24 and crimped. For this reason, there are multiple projections P and holes H, and multiple bosses 24c of the insulator 24 in which the holes H are formed. In this embodiment, there are eight fixing points F, but there may be two or more, for example, four.

[0046] The electric pump 100 configured as described above has a stator 21 fixing structure in which the insulator 24 of the stator 21 is fixed to the housing body 41, which serves as the housing, by a projection P that is crimped while the insulator 24 of the stator 21 is inserted through the hole H.

[0047] This structure allows the stator 21 to be fixed to the housing body 41 simply by inserting the projection P into the hole H and crimping it, thus improving the ease of assembly of the stator 21. Specifically, heating for shrink fitting is unnecessary, and crimping can be performed using a crimping machine, thus shortening the assembly process time. In addition, since bolts for fixing the stator are unnecessary, the number of parts is reduced, improving ease of assembly. With this structure, since shrink fitting is not performed, the insulator 24 will not crack or break due to the effects of shrink fitting, and the number of parts can be reduced, thus lowering costs.

[0048] In the stator 21 fixing structure, the stator core 22 abuts against the stepped portion 48 (see Figure 1) of the housing body 41 to position it in the axial direction. This allows the stator 21 to be accurately positioned in the axial direction.

[0049] When the stator core 22 is positioned on the stepped portion 48, as shown in Figure 4, a gap C is formed between the first bottom surface 43b of the housing body portion 41 and the back surface 24b of the flange portion 24a of the insulator 24, while the projection P is not yet crimped. Therefore, when the projection P is crimped in this state, the insulator 24 deforms and becomes fixed in place.

[0050] Once the insulator 24 is deformed and fixed in place, it remains deformed, which puts a strain on it. For this reason, the insulator 24 may be configured as follows.

[0051] Figures 5 and 6 show the first and second modified examples of the insulator 24. In Figures 5 and 6, for the sake of explanation, the insulator 24 is shown superimposed on the housing body 41, etc., indicated by the dashed line.

[0052] As shown in Figures 5 and 6, the modified insulator 24 has a deformed portion 24d that extends in a groove-like manner along the circumferential direction, located radially inward from the hole H.

[0053] In the first modified example shown in Figure 5, the deformed portion 24d is formed on the flange portion 24a radially inward from the hole H. The deformed portion 24d is formed as a portion that is bent in a convex shape toward the opening 42 side in the longitudinal cross-section (radial cross-section) of the insulator 24. In the longitudinal cross-section, the deformed portion 24d is formed within the range from the portion of the insulator 24 attached to the stator core 22 to the hole H. The deformed portion 24d is formed on the connection portion 24f of the flange portion 24a that is connected to the outer wall portion 24e of the insulator 24. The outer wall portion 24e extends cylindrically toward the opening 42 side (upper side in Figure 5) in the axial direction from the flange portion 24a. The deformed portion 24d can be provided over the entire connection portion 24f in the circumferential direction.

[0054] In the second modified example shown in Figure 6, the deformed portion 24d is formed on the outer wall portion 24e radially inward from the hole H. The deformed portion 24d is formed as a portion that is bent in a convex shape toward the radially outward direction in the longitudinal cross-section of the insulator 24. The deformed portion 24d is formed adjacent to the connection portion 24g of the outer wall portion 24e with the flange portion 24a. In the longitudinal cross-section, the deformed portion 24d is formed within the range from the portion of the insulator 24 attached to the stator core 22 to the hole H. The deformed portion 24d is formed adjacent to the connection portion 24g from the back surface 24b side (lower side in Figure 6).

[0055] In these modified versions, the insulator 24 has a deformable portion 24d that extends in a groove-like manner along the circumferential direction, located radially inward from the hole H. Therefore, the deformation of the insulator 24 caused by crimping due to the gap C (see Figure 4) can be absorbed by the deformable portion 24d. This reduces the load on the insulator 24 and prevents a decrease in the durability of the insulator 24.

[0056] In these modified examples, the deformation portion 24d is formed by a portion that is bent in a convex shape in cross-section, allowing the deformation portion 24d to deform like a spring and absorb the deformation of the insulator 24. Furthermore, in the vertical cross-section, by forming the deformation portion 24d within the range from the portion of the insulator 24 attached to the stator core 22 to the hole H, the deformation occurring between the fixing points can be absorbed by the deformation portion 24d. In addition, by forming the deformation portion 24d near the connection portion 24f of the flange portion 24a and near the connection portion 24g of the outer wall portion 24e, the connection points between the flange portion 24a and the outer wall portion 24e can be protected from stress caused by deformation.

[0057] Figure 7 shows a modified example of the axial positioning of the stator 21. In this example, the first bottom surface 43b of the housing body 41 and the back surface 24b of the flange portion 24a of the insulator 24 are in contact with each other without the projection P being crimped. In other words, in this example, the first bottom surface 43b and the back surface 24b are in contact with each other to form a positioning portion L that positions the stator 21 axially relative to the housing body 41.

[0058] In this way, the stator 21 can be positioned axially simply by machining the first bottom surface 43b of the housing body 41 facing the insulator 24 so that it also serves as a positioning surface. Therefore, it is not necessary to form a stepped portion 48 (see Figure 1), and the amount of machined surface can be reduced. Also, since it is not necessary to form a stepped portion 48, the second housing recess 43c can be widened radially on the second bottom surface 43d side (lower side in Figure 1) relative to the stator core 22, making it easier for the coil wiring from the coil 23 wound around the stator core 22 to escape radially.

[0059] In this example, similar to the state shown in Figure 3, the flange portion 24a, which has a back surface 24b as a second opposing surface, is sandwiched between the crimped projection P and the housing body portion 41. This ensures that the stator 21 is accurately positioned in the axial direction. In the flange portion 24a, the fixing surface H3 of the hole H formed in the flange portion 24a is sandwiched between the projection P of the crimped portion and the first bottom surface 43b of the housing body portion 41 as a first opposing surface.

[0060] The flange portion 24a may be sandwiched between the crimped projection P and the housing body portion 41 when the stepped portion 48 (see Figure 1) is formed on the housing body portion 41. This prevents the stator 21, which is positioned on the stepped portion 48, from moving toward the opening 42 (upper side in Figure 1), thereby allowing the stator 21 to be accurately positioned in the axial direction.

[0061] Figure 8 shows a modified example of radial positioning of the stator 21. In this example, the projection P contacts the inner surface of the hole H by the crimped and deformed portion. In this example, the inner diameter of the large-diameter portion H2 is set so that the crimped and deformed portion of the projection P contacts the inner surface of the hole H. The projection P is configured in this way at at least two or more fixing points F (see Figure 2), and the two fixing points F are arranged diagonally with respect to the center of the stator core 22.

[0062] In this way, the stator 21 is positioned radially by the projections P crimped at at least two or more fixing points F. This makes it easier to position the stator core 22 on the inner circumferential surface of the second housing recess 43c (see Figure 1) of the housing body 41 (i.e., spigot fitting). Consequently, the stator core 22 is easier to insert into the second housing recess 43c, improving ease of assembly. Furthermore, by arranging the two fixing points F diagonally with respect to the center of the stator core 22, radial positioning accuracy can be improved compared to the case where they are not arranged diagonally.

[0063] The stator core 22 is positioned for alignment with the motor rotor 25. For this reason, the manufacturing method of the motor unit 20 as an electric motor or electric pump 100, including the fixing structure of the stator 21, may include simultaneously press-fitting the stator core 22 and the motor rotor 25 while positioning the stator core 22 axially with respect to the motor rotor 25.

[0064] In this case, the stator core 22 is press-fitted into the second receiving recess 43c instead of being fitted with a spigot. Alternatively, the stator core 22 and the motor rotor 25 can be press-fitted simultaneously using a press-fitting jig that is manufactured so that the stator core 22 is press-fitted to a predetermined position (i.e., so that the stator core 22 is axially positioned relative to the motor rotor 25) while the motor rotor 25 is press-fitted to its press-fitting end. This manufacturing method also eliminates the need to process the stepped portion 48.

[0065] Four of the eight fixing points F (see Figure 2), for example, four points that are not adjacent to each other in the circumferential direction, may be receiving surfaces consisting of a first bottom surface 43b without protrusions P and a back surface 24b without holes H. This increases the contact area between the first bottom surface 43b and the back surface 24b on the four receiving surfaces where protrusions P are not formed when the protrusions P are crimped at the four fixing points F, thereby improving the adhesion. Even if a gap C (see Figure 4) is formed, the first bottom surface 43b and the back surface 24b, which serve as receiving surfaces, can still be brought into close contact as the insulator 24 deforms due to the crimping.

[0066] The insulator 24 may consist of a first insulator mounted on the stator core 22 from one axial side (upper side in Figure 1) and a second insulator mounted on the stator core 22 from the other axial side (lower side in Figure 1). In this case, the flange portion 24a can be provided on the first insulator.

[0067] The projection P is not limited to having a recess D on its tip surface, but may also have a crimped portion with a split structure that can be bent by crimping, for example, like a cotter pin.

[0068] The deformed portion 24d may be formed in the shape of a notch. On the other hand, by forming the deformed portion 24d with a portion that is bent in a convex shape in cross-section, it becomes easier to ensure the strength of the deformed portion 24d. The portion that is bent in a convex shape in cross-section may be bent in a curved shape or bent in a straight line. The deformed portion 24d may be composed of a portion with a wavy cross-section in which groove-like portions are continuously formed.

[0069] The housing body 41 may be formed separately into a part that houses the pump unit 10 and a part that houses the motor unit 20, and these may be joined together by bolt fastening or the like.

[0070] The configuration, operation, and effects of the embodiments of the present invention will be described below.

[0071] The fixing structure of the stator 21 comprises the stator 21 and a housing body 41 that houses the stator 21. The stator 21 has an annular stator core 22, an insulator 24 attached to the stator core 22, and a coil 23 wound around the stator core 22 via the insulator 24. The housing body 41 and the insulator 24 each have a first bottom surface 43b as a first opposing surface and a back surface 24b of the flange portion 24a as a second opposing surface, respectively, which face each other in the axial direction. The housing body 41 has a projection P protruding from the first bottom surface 43b, and the insulator 24 has a hole H that opens on the back surface 24b through which the projection P is inserted. The insulator 24 of the stator 21 is fixed to the housing body 41 by the projection P which is crimped while inserted through the hole H.

[0072] With this configuration, the stator 21 can be fixed to the housing body 41 simply by inserting the projection P through the hole H and crimping it, thus improving the ease of assembly of the stator 21.

[0073] The housing body portion 41 has a stepped portion 48 against which the stator core 22 abuts and is positioned in the axial direction.

[0074] This configuration allows the stator 21 to be precisely positioned in the axial direction.

[0075] The insulator 24 may have a deformable portion 24d that extends in a groove-like manner along the circumferential direction, located radially inward from the hole H.

[0076] With this configuration, the stator core 22 is positioned on the stepped portion 48, and with the projection P not yet crimped, the deformation that occurs in the insulator 24 when the projection P is crimped, caused by the gap C between the first bottom surface 43b of the housing body portion 41 and the back surface 24b of the flange portion 24a of the insulator 24, can be absorbed by the deformed portion 24d, thereby suppressing the load on the insulator 24 and thus preventing a decrease in the durability of the insulator 24.

[0077] The first bottom surface 43b of the housing body 41 and the back surface 24b of the flange portion 24a of the insulator 24 may come into contact with each other to form a positioning portion L that positions the stator 21 in the axial direction relative to the housing body 41.

[0078] With this configuration, the stator 21 can be positioned in the axial direction simply by machining the first bottom surface 43b of the housing body 41 facing the insulator 24 so that the first bottom surface 43b also serves as a positioning surface, thus reducing the amount of machined surface.

[0079] The insulator 24 has a flange portion 24a with a back surface 24b, and the flange portion 24a is sandwiched between a crimped projection P and the housing body portion 41.

[0080] This configuration allows the stator 21 to be precisely positioned in the axial direction.

[0081] The fixing structure of the stator 21 has multiple fixing points F in which projections P are inserted through holes H and crimped, and projections P may contact the inner surface of holes H at at least two or more fixing points F by the crimped and deformed portion.

[0082] With this configuration, the stator 21 is positioned radially by projections P crimped at at least two or more fixing points F, thereby easing the positioning on the inner circumferential surface of the second housing recess 43c of the housing body 41.

[0083] The electric pump 100, which has a fixed structure for the stator 21, comprises a pump unit 10 that discharges liquid and a motor unit 20 that rotates the drive shaft 1 to drive the pump unit 10. The motor unit 20 has a stator 21, and the housing body 41 houses the pump unit 10 and the motor unit 20.

[0084] This configuration improves the ease of assembly of the stator 21 in an electric pump 100 in which the pump section 10 and the motor section 20 are integrated.

[0085] Although embodiments of the present invention have been described above, these embodiments only represent a part of the application examples of the present invention, and are not intended to limit the technical scope of the present invention to the specific configurations of the above embodiments. [Explanation of Symbols]

[0086] 10...Pump section, 20...Motor section, 21...Stator, 22...Stator core, 23...Coil, 24...Insulator, 24a...Flange section, 24b...Back surface (second opposing surface), 24d...Deformed section, 41...Housing main body section (housing), 43b...First bottom surface (first opposing surface), 48...Step section, 100...Electric pump, F...Fixing point, H...Hole, L...Positioning part, P...Protrusion

Claims

1. stator and, The stator is housed in a housing, The stator comprises an annular stator core, an insulator attached to the stator core, and a coil wound around the stator core via the insulator. The housing and the insulator each have a first opposing surface and a second opposing surface that face each other in the axial direction, The housing has a projection that protrudes from the first opposing surface, The insulator has a hole that opens to the second opposing surface through which the projection is inserted, The insulator of the stator is fixed to the housing by the projection that is crimped while inserted through the hole. A stator fixing structure characterized by the above.

2. A stator fixing structure according to claim 1, The housing has a stepped portion against which the stator core abuts and is positioned in the axial direction. A stator fixing structure characterized by the above.

3. A stator fixing structure according to claim 2, The insulator has a deformable portion that extends in a groove-like manner along the circumferential direction, located radially inward from the hole. A stator fixing structure characterized by the above.

4. A stator fixing structure according to claim 1, The first opposing surface of the housing and the second opposing surface of the insulator come into contact with each other to form a positioning section that positions the stator axially relative to the housing. A stator fixing structure characterized by the above.

5. A stator fixing structure according to claim 1, The insulator has a flange portion having the second opposing surface, The flange portion is sandwiched between the crimped projection and the housing. A stator fixing structure characterized by the above.

6. A stator fixing structure according to claim 1, The aforementioned projection has multiple fixing points that are crimped while being inserted into the aforementioned hole, The projections abut against the inner surface of the holes at at least two of the fixing points by the crimped and deformed portions. A stator fixing structure characterized by the above.

7. An electric pump comprising a stator fixing structure according to any one of claims 1 to 6, A pump section that discharges liquid, It comprises a motor unit that rotates the drive shaft to drive the pump unit, The motor section has the stator, The housing accommodates the pump section and the motor section. An electric pump characterized by the following features.

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