Electric oil pump

Abstract

The electric oil pump of the present invention comprises: a rod body; a motor section having a rotor fixed to the rod body and rotatable; a pump section being driven by the power of the motor section to pressurize and pump oil; and a housing housing the motor section and the pump section. The pump section has: an inner rotor connected to one axial side of the rod body and having external teeth; and an outer rotor surrounding the inner rotor from the radially outer side and having internal teeth meshing with the external teeth. The housing has a resin housing body and a metal housing body. The housing body has: a motor housing section housing the motor section; a pump housing section housing the pump section; and a connecting hole section connecting the interior of the motor housing section and the interior of the pump housing section, through which the rod body passes axially. The metal housing body has a cylindrical portion extending axially. Radially, the cylindrical portion is disposed between the inner circumferential surface of the rod body and the connecting hole section.

Description

Technical Field

[0001] This invention relates to an electric oil pump. Background Technology

[0002] A pump is known to include: a rotary motor having a rotatable rod; a pump mechanism connected to the rod; and a housing that houses the rotary motor and the pump mechanism respectively, wherein the pump is configured such that the rod is supported for rotation by the inner circumferential surface of the inner cylindrical portion of the main body of the housing (e.g., Patent Document 1).

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2023-090277 Summary of the Invention

[0006] The problem that the invention aims to solve

[0007] In the pumps described above, where the housing is made of resin material for the purpose of reducing pump weight, the inner circumferential surface of the main body's inner cylinder is prone to wear due to friction with the rod during pump operation. Therefore, the pump's durability may be reduced.

[0008] In view of the above circumstances, one of the objectives of this invention is to provide an electric oil pump that can achieve weight reduction and suppress the reduction of durability.

[0009] Solution for solving the problem

[0010] One embodiment of the electric oil pump of the present invention comprises: a rod extending axially; a motor portion having a rotor fixed to the rod and rotatable; a pump portion driven by the power of the motor portion to pressurize oil; and a housing housing the motor portion and the pump portion. The pump portion has: an inner rotor connected to one axial side of the rod and having external teeth; and an outer rotor surrounding the inner rotor radially outward and having internal teeth meshing with the external teeth. The housing has a resin housing body portion and a metal housing portion. The housing body portion has: a motor housing portion housing the motor portion; a pump housing portion housing the pump portion; and a connecting hole portion connecting the interior of the motor housing portion to the interior of the pump housing portion, through which the rod passes axially. The metal housing portion has a cylindrical portion extending axially. Radially, the cylindrical portion is disposed between the inner circumferential surface of the rod and the connecting hole portion.

[0011] Invention Effects

[0012] According to one aspect of the present invention, a lightweight design can be achieved in an electric oil pump, and the reduction in durability can be suppressed. Attached Figure Description

[0013] Figure 1 This is a first perspective view showing an electric oil pump according to one embodiment.

[0014] Figure 2 This is a cross-sectional view showing one embodiment of an electric oil pump.

[0015] Figure 3 This is an enlarged cross-sectional view showing a portion of an electric oil pump according to one embodiment.

[0016] Figure 4 This is a cross-sectional view showing one embodiment of an electric oil pump, and is Figure 3 Sectional view IV-IV.

[0017] Figure 5 This is a second perspective view showing an electric oil pump according to one embodiment.

[0018] Figure 6 This is a top view of the pump cover and base plate of one embodiment viewed from the other side of the axial direction.

[0019] Figure 7 This is a perspective view of the metal housing portion according to one embodiment.

[0020] Figure 8 This is a perspective view of the base plate portion of one embodiment.

[0021] Figure 9 This is a cross-sectional view showing one embodiment of an electric oil pump, and is Figure 3 IX-IX sectional view.

[0022] Explanation of reference numerals in the attached figures

[0023] 1: Electric oil pump; 10: Housing; 11: Housing body; 12: Motor housing; 16: Pump housing; 17e: Top surface; 18c: Connecting hole; 18g: Connecting groove; 19: Receiving groove; 25: Metal housing; 27: Top wall; 27a: Second notch; 28: Top wall through hole; 29: Cylindrical part; 29a: First notch; 40: Motor part; 41: Rotor; 43: Rod body; 60: Pump part; 61: Inner rotor; 61a: Outer tooth; 62: Outer rotor; 62a: Inner tooth. Detailed Implementation

[0024] Hereinafter, an electric oil pump according to an embodiment of the present invention will be described with reference to the accompanying drawings. It should be noted that the scope of the present invention is not limited to the following embodiments, and modifications can be made arbitrarily within the scope of the technical concept of the present invention. Furthermore, in the following drawings, for ease of understanding of the various components, the actual structure may sometimes differ from the scale, quantity, etc., in each component.

[0025] In each figure, the Z-axis is appropriately shown. The direction in which the Z-axis extends is the direction in which the rotation axis J extends in the embodiments described below. The rotation axis J shown in each figure is an imaginary axis. In the following description, the direction in which the rotation axis J extends, that is, the direction parallel to the Z-axis, is referred to as the "axial direction". The side in which the arrow of the Z-axis points (+Z side) in the axial direction is referred to as the "axial side" or "lower side", and the side opposite to the side in which the arrow of the Z-axis points (-Z side) in the axial direction is referred to as the "axial other side" or "upper side". In the following description, the radial direction centered on the rotation axis J is simply referred to as "radial", and the circumferential direction centered on the rotation axis J is simply referred to as "circumferential direction". In each figure, the circumferential direction is represented by the arrow θ. It should be noted that the upper side and lower side are names used only to illustrate the relative positional relationship of each part, and the relative positional relationship of each part may also be a configuration relationship other than the configuration relationship shown by these names.

[0026] Figure 1 This is a perspective view showing the electric oil pump 1 according to this embodiment. The electric oil pump 1 of this embodiment is an electric oil pump that delivers oil as a fluid. The fluid may also be other liquids such as water. The electric oil pump 1 is used, for example, to supply oil to a mounted device such as a vehicle. The mounted device may be an automatic transmission or a drive unit that drives the axle of the vehicle. Figure 2 As shown, the electric oil pump 1 includes a housing 10, a motor 40, a rod 43, a control device 56, and a pump 60.

[0027] The housing 10 is a generally cylindrical shape extending axially. The housing 10 houses the motor unit 40, the rod body 43, the control device 56, and the pump unit 60. The housing 10 has a main body portion 11, a cover portion 21, a metal housing portion 25, a pump cover 31, and a base plate portion 37. In this embodiment, the main body portion 11, the cover portion 21, the metal housing portion 25, the pump cover 31, and the base plate portion 37 are independent components.

[0028] The housing body 11 is a generally cylindrical shape extending axially around the rotation axis J. The housing body 11 internally houses the motor part 40, the rod body 43, and the pump part 60. In this embodiment, the housing body 11 is made of resin. Polybutylene terephthalate (PBT), polyphenylene sulfide (PPS), and polycarbonate (PC) can be used as materials constituting the housing body 11. In this embodiment, the housing body 11 is formed by inserting the metal housing part 25 and the stator 50 (described later) of the motor part 40 as insert members. Thus, the metal housing part 25 is fixed to the housing body 11. Therefore, in the assembly process of the electric oil pump 1, for example, it is not necessary to fix the metal housing part 25 to the housing body 11 using adhesive, thereby suppressing the increase in assembly time of the electric oil pump 1. Furthermore, the stator 50 is embedded inside the housing body 11. The housing body 11 has a motor housing part 12, a pump housing part 16, and ribs 20.

[0029] The motor receiving portion 12 is the upper part of the housing body portion 11. The motor receiving portion 12 is generally cylindrical and extends axially about the rotation axis J. The motor receiving portion 12 has an opening at the top. The motor receiving portion 12 houses the motor portion 40. The motor receiving portion 12 has a first sidewall portion 12a, a stator holding portion 12g, and a mounting portion 14.

[0030] The first sidewall portion 12a is a generally cylindrical shape extending axially around the rotation axis J. The first sidewall portion 12a surrounds the upper parts of the motor portion 40 and the rod body 43 radially outward. A cover portion 21 is fixed to the upper end of the first sidewall portion 12a. The first sidewall portion 12a is provided with a first annular groove portion 12c and a first protrusion portion 12e.

[0031] The first annular groove 12c is a groove that is recessed radially inward from the radially outward surface of the first sidewall portion 12a and extends circumferentially. The first annular groove 12c extends circumferentially all around. An O-ring 91 is embedded inside the first annular groove 12c. The first protrusion 12e is a protrusion that protrudes upward from the upward surface of the first sidewall portion 12a. The first protrusion 12e extends circumferentially all around.

[0032] The stator holding portion 12g is approximately annular about the rotation axis J. The stator holding portion 12g is positioned radially inward from the first sidewall portion 12a. The stator holding portion 12g is connected to the first sidewall portion 12a. The stator 50, described later, of the motor portion 40 is embedded inside the stator holding portion 12g. Therefore, the housing body portion 11 holds the stator 50. A substrate holding portion 12h is provided in the stator holding portion 12g.

[0033] The substrate holding portion 12h is a columnar shape that protrudes upward from the upward-facing surface of the stator holding portion 12g. Although not shown in the figure, multiple substrate holding portions 12h are provided in the stator holding portion 12g. The substrate holding portions 12h are arranged at intervals between each other along the circumferential direction.

[0034] The mounting portion 14 protrudes radially outward from the radially outward surface of the first sidewall portion 12a. The mounting portion 14 is provided with a hole 14a extending axially through the mounting portion 14. For example... Figure 1 As shown, in this embodiment, the motor housing 12 has two mounting portions 14. The motor housing 12 may have three or more mounting portions 14. Each mounting portion 14 is radially opposed to the other across the rotation axis J. A collar portion 14c is inserted into each hole portion 14a. Each collar portion 14c is fixed to the inner circumferential surface of the hole portion 14a. Each collar portion 14c is made of metal. Figure 2 As shown, the collar portion 14c is a generally cylindrical shape extending axially. Bolts (not shown) pass axially through the interior of each collar portion 14c and are screwed into internally threaded holes (not shown) on the mounted body. Each mounting portion 14 is fixed to the mounted body. That is, the electric oil pump 1 is fixed to the mounted body.

[0035] like Figure 1 As shown, the pump housing 16 is the lower part of the housing body 11. The pump housing 16 is a generally cylindrical shape extending axially about the rotation axis J. Figure 3 As shown, the downward-facing surface of the pump housing 16 is the lower end of the housing body 11. The pump housing 16 has an opening 17c that opens on the lower side, i.e., on the axial side (+Z side). The pump housing 16 houses the pump part 60 inside. The pump housing 16 has a second side wall 16a and an annular wall 18. A receiving recess 17 is provided in the pump part 60. That is, the housing body 11 has a receiving recess 17.

[0036] The second sidewall portion 16a is a generally cylindrical shape extending axially around the rotation axis J. The second sidewall portion 16a radially surrounds the lower portions of both the pump portion 60 and the rod body 43. A pump cover 31 is fixed to the lower end of the second sidewall portion 16a. Figure 1 As shown, the outer diameter of the second sidewall portion 16a is smaller than the outer diameter of the first sidewall portion 12a. For example... Figure 3 As shown, a second protrusion 16c is provided on the second sidewall portion 16a. The second protrusion 16c is a protrusion that protrudes downward from the downward-facing surface of the second sidewall portion 16a. The second protrusion 16c extends circumferentially throughout the entire perimeter.

[0037] The receiving recess 17 is a hole recessed upward from the lower side of the pump receiving portion 16. That is, the receiving recess 17 is a hole recessed upward from the lower side (+Z side) of the housing body portion 11 to the other side (-Z side). The pump portion 60 is accommodated inside the receiving recess 17. The receiving recess 17 has an inner peripheral surface 17a and a top surface 17e. Specifically, the pump receiving portion 16 has a top surface 17e.

[0038] The inner circumferential surface 17a of the recess is the radially inward-facing surface of the inner surface that accommodates the recess 17. For example... Figure 4 As shown, the inner circumferential surface 17a of the recess is approximately circular, surrounding the axis of rotation J. When viewed axially, the center of the inner circumferential surface 17a of the recess deviates from the axis of rotation J. Figure 3 As shown, the inner circumferential surface 17a of the recess is radially opposed to the pump portion 60. The inner circumferential surface 17a of the recess surrounds the pump portion 60 from the radially outer side. The lower end of the inner circumferential surface 17a of the recess is an opening 17c.

[0039] The top surface 17e is the downward-facing surface of the inner surface of the recess 17. The top surface 17e is the downward-facing surface of the annular wall portion 18. The top surface 17e is located above the pump portion 60, i.e., on the opposite side (-Z side) in the axial direction. The top surface 17e is axially opposed to the pump portion 60.

[0040] The annular wall portion 18 is approximately circular about the rotation axis J. The radially outer end of the annular wall portion 18 is circumferentially connected to the inner circumferential surface of the second side wall portion 16a. The annular wall portion 18 is positioned lower than the motor portion 40 and higher than the pump portion 60. As described above, the downward-facing surface of the annular wall portion 18 is the top surface 17e. The annular wall portion 18 is provided with an inner cylinder portion 18a, a communicating hole portion 18c, an outlet hole 18e, a communicating groove portion 18g, and a receiving groove portion 19. That is, the housing body portion 11 has a communicating hole portion 18c. The communicating groove portion 18g and the receiving groove portion 19 are respectively provided on the top surface 17e.

[0041] The inner cylinder portion 18a protrudes upward from the radial inner edge of the annular wall portion 18. The inner cylinder portion 18a is generally cylindrical about the axis of rotation J. The inner circumferential surface of the inner cylinder portion 18a is axially connected to the inner circumferential surface of the annular wall portion 18.

[0042] The connecting hole 18c is an axially penetrating hole that passes through both the annular wall portion 18 and the inner cylinder portion 18a. The connecting hole 18c is formed by the inner circumferential surface of the annular wall portion 18 and the inner circumferential surface of the inner cylinder portion 18a. When viewed axially, the connecting hole 18c is approximately circular about the rotation axis J. The connecting hole 18c connects the interior of the motor housing portion 12 with the interior of the housing recess 17. That is, the connecting hole 18c connects the interior of the motor housing portion 12 with the interior of the pump housing portion 16. The rod body 43 passes through the connecting hole 18c axially. The outlet hole 18e is an axially penetrating hole that passes through the annular wall portion 18. The outlet hole 18e is located on the radially outer portion of the annular wall portion 18.

[0043] The receiving groove 19 is a groove recessed from the top surface 17e upwards, i.e., on the other side of the axial direction (-Z side). The receiving groove 19 opens on the lower side. In this embodiment, two receiving grooves 19 are provided on the top surface 17e. The two receiving grooves 19 include a first suction-side groove 19a and a first discharge-side groove 19c.

[0044] like Figure 4 As shown, when viewed axially, the first suction-side groove 19a and the first discharge-side groove 19c are both approximately arc-shaped grooves extending circumferentially. That is, the receiving groove 19 is a groove extending circumferentially. The first suction-side groove 19a and the first discharge-side groove 19c are located at different positions circumferentially. The first suction-side groove 19a and the first discharge-side groove 19c are radially opposed. More specifically, the first suction-side groove 19a and the first discharge-side groove 19c are radially opposed across the rotation axis J. Figure 3 and Figure 4 As shown, when viewed axially, the first suction side groove 19a overlaps with the outlet hole 18e. Figure 3 As shown, the outlet hole 18e connects the interior of the motor housing 12 with the interior of the first suction side groove 19a.

[0045] The connecting groove 18g is a groove recessed from the top surface 17e upwards, i.e., on the other side of the axial direction (-Z side). For example... Figure 4As shown, the connecting groove 18g is a groove extending linearly in the radial direction. The radially inner end of the connecting groove 18g opens into the connecting hole 18c. In this embodiment, the radially outer end of the connecting groove 18g opens into the first discharge-side groove 19c. Thus, in this embodiment, the connecting groove 18g connects the connecting hole 18c to the first discharge-side groove 19c. That is, the connecting groove 18g connects the connecting hole 18c to the receiving groove 19. It should be noted that, alternatively, the radially inner end of the connecting groove 18g may open into the connecting hole 18c, and the radially outer end of the connecting groove 18g may open into the first suction-side groove 19a. In this case, the connecting groove 18g connects the connecting hole 18c to the first suction-side groove 19a. That is, the connecting groove 18g connects the connecting hole 18c to the receiving groove 19.

[0046] like Figure 1 As shown, rib 20 is provided on the outer peripheral surface of the second sidewall portion 16a, i.e., the radially outward surface of the pump housing portion 16. As described above, in this embodiment, the housing body portion 11 is made of resin. Therefore, compared to the case where the housing body portion 11 is made of metal, it is difficult to improve the strength of the housing body portion 11. In contrast, in this embodiment, by providing rib 20 on the radially outward surface of the pump housing portion 16, the strength of the housing body portion 11 can be appropriately improved. Rib 20 is a plate-shaped part that protrudes radially outward from the pump housing portion 16. The plate surface of rib 20 faces circumferentially. Rib 20 extends axially. The upper end of rib 20 is connected to the first sidewall portion 12a. That is, rib 20 is connected to the motor housing portion 12. The housing body portion 11 has a plurality of ribs 20. In this embodiment, the housing body portion 11 has four ribs 20. The number of ribs 20 in the housing body portion 11 can be three or less, or five or more. Each rib 20 is arranged at intervals along the circumferential direction. In this embodiment, the ribs 20 are arranged at approximately equal intervals along the circumferential direction. Therefore, the unevenness in strength of the main body 11 in the circumferential direction can be appropriately reduced. Figure 5 As shown, the plurality of ribs 20 includes a first rib 20a and a second rib 20c. In this embodiment, the plurality of ribs 20 includes one first rib 20a and three second ribs 20c. The number of first ribs 20a and the number of second ribs 20c included in the plurality of ribs 20 are not limited to this embodiment.

[0047] The first rib 20a and each of the second ribs 20c are respectively provided on the radially outward side of the pump housing 16. The first rib 20a and each of the second ribs 20c extend axially. The second ribs 20c and the first rib 20a are arranged in a manner that is spaced apart from each other circumferentially. The lower end of the first rib 20a, i.e., the axial side (+Z side), is located lower than the lower ends of the respective second ribs 20c.

[0048] like Figure 2 As shown, the cover 21 is a generally cylindrical shape that protrudes axially about the rotation axis J. The cover 21 has an opening on its lower side. The cover 21 is fixed to the upper end of the housing body 11. The cover 21 seals the upper opening of the motor housing 12. The internal space of the cover 21 is connected to the internal space of the motor housing 12. A control device 56 is housed inside the cover 21. In this embodiment, the cover 21 is made of resin. Polybutylene terephthalate (PBT), polyphenylene sulfide (PPS), and polycarbonate (PC) can be used as the material constituting the cover 21. The cover 21 can also be made of other materials such as metal. The cover 21 has a peripheral wall portion 22 and a substrate cover portion 23.

[0049] The cover peripheral wall portion 22 is a generally cylindrical shape that protrudes axially about the rotation axis J. The cover peripheral wall portion 22 surrounds the control device 56 radially outward. A second annular groove portion 22a is provided in the cover peripheral wall portion 22. The second annular groove portion 22a is a groove that is recessed from the lower side of the cover peripheral wall portion 22 and extends circumferentially. The first protrusion 12e of the motor receiving portion 12 is inserted into the interior of the second annular groove portion 22a. Therefore, the radial position of the cover portion 21 relative to the housing body portion 11 is determined. In this embodiment, the lower end of the cover peripheral wall portion 22 and the upper end of the first side wall portion 12a are joined together by welding circumferentially. As a result, the housing body portion 11 and the cover portion 21 can be properly sealed, thus appropriately improving the airtightness of the electric oil pump 1. In addition, there is no need to provide additional sealing members such as O-rings to seal between the housing body portion 11 and the cover portion 21, thus suppressing the increase in the number of components of the electric oil pump 1.

[0050] like Figure 1 As shown, the substrate cover 23 is a roughly circular plate centered on the rotation axis J. Figure 2 As shown, the substrate cover 23 is positioned above the control device 56. The radial outer edge of the substrate cover 23 is connected to the upper end of the cover peripheral wall 22.

[0051] like Figure 3As shown, the pump cover 31 is approximately annular about the rotation axis J. The pump cover 31 is positioned lower than the pump section 60. The pump cover 31 is fixed to the lower end of the pump receiving section 16. The pump cover 31 covers the pump section 60 from below. The pump cover 31 seals the receiving recess 17 from below, i.e., on the axial side (+Z side). That is, the pump cover 31 seals the opening 17c from below. In this embodiment, the pump cover 31 is made of resin. Polybutylene terephthalate (PBT), polyphenylene sulfide (PPS), and polycarbonate (PC) can be used as the material constituting the pump cover 31. The pump cover 31 can also be made of other materials such as metal. In this embodiment, the pump cover 31 is formed by inserting the base plate portion 37 as an insert member. Therefore, the base plate portion 37 is fixed to the pump cover 31. Therefore, in the assembly process of the electric oil pump 1, for example, it is not necessary to fix the base plate 37 to the pump cover 31 with adhesive, thus more appropriately suppressing the increase in assembly time of the electric oil pump 1. The pump cover 31 has a cover body 32 and a protruding cylinder 35.

[0052] The main body 32 is the upper part of the pump cover 31. The main body 32 is approximately annular about the axis of rotation J. The main body 32 includes a suction port 32a, a discharge port 32b, a discharge outlet 32c, a third annular groove 32e, and a cover groove 33. That is, the pump cover 31 has a cover groove 33. Figure 5 As shown, a protrusion 34 is provided in the main body 32 of the cover. That is, a protrusion 34 is provided in the pump cover 31.

[0053] like Figure 3 As shown, the suction port 32a is an opening on the downward-facing surface of the main body 32. The suction port 32a opens on the lower side. Although not shown in the figure, when viewed axially, the suction port 32a is an arc shape extending circumferentially. As described later, the suction port 32a is connected to the second suction-side groove 33a. Oil from outside the electric oil pump 1 is drawn into the interior of the housing 10 via the suction port 32a.

[0054] The discharge hole 32b is a hole extending radially inward from the outermost surface of the cover body 32. As described later, the radially inward end of the discharge hole 32b is connected to the second discharge side groove 33c. Figure 1 As shown, the discharge port 32b opens radially outward. The discharge outlet 32c is an opening located at the radially outward end of the discharge port 32b. The discharge outlet 32c is provided on the radially outward-facing surface of the pump cover 31. Figure 3 As shown, the oil compressed in the pump section 60 is discharged to the outside of the electric oil pump 1 through the discharge port 32b and the discharge outlet 32c.

[0055] The third annular groove 32e is a groove that is recessed from the upper side of the cover body 32 and extends circumferentially. The second protrusion 16c of the pump housing 16 is inserted inside the third annular groove 32e. This determines the radial position of the pump cover 31 relative to the housing body 11. In this embodiment, the lower end of the second sidewall portion 16a and the upper end of the cover body 32 are circumferentially joined together by welding. That is, the pump housing 16 and the pump cover 31 are circumferentially joined together by welding. Therefore, the housing body 11 and the pump cover 31 can be properly sealed, thus appropriately improving the airtightness of the electric oil pump 1. Furthermore, there is no need to separately provide sealing members such as O-rings to seal the housing body 11 and the pump cover 31, thus suppressing an increase in the number of components in the electric oil pump 1.

[0056] The cover groove 33 is a groove recessed downward from the upper surface of the cover body 32. For example... Figure 6 As shown, the cover groove 33 extends circumferentially. That is, a cover groove 33 is provided on the surface of the pump cover 31 facing upwards, i.e., on the other side of the axial direction (-Z side), and extends circumferentially with a downward recess on one side of the axial direction (+Z side). Figure 3 As shown, the cover groove 33 has an opening on the upper side. In this embodiment, two cover grooves 33 are provided on the cover body 32. That is, two cover grooves 33 are provided on the pump cover 31. The two cover grooves 33 include a second suction side groove 33a and a second discharge side groove 33c.

[0057] like Figure 6 As shown, when viewed axially, the second suction-side groove 33a and the second discharge-side groove 33c are both arc-shaped grooves extending circumferentially. That is, the cover groove 33 is a groove extending circumferentially. The second suction-side groove 33a and the second discharge-side groove 33c are located at different positions in the circumferential direction. The second suction-side groove 33a and the second discharge-side groove 33c are opposite each other in the radial direction. That is, the two cover grooves 33 are opposite each other in the radial direction. More specifically, the second suction-side groove 33a and the second discharge-side groove 33c are opposite each other in the radial direction across the rotation axis J.

[0058] like Figure 3 As shown, when viewed axially, the second suction-side groove 33a overlaps with the suction port 32a. The interior of the second suction-side groove 33a is connected to the suction port 32a. When viewed axially, the second suction-side groove 33a overlaps with the first suction-side groove 19a. Figure 4 and Figure 6 As shown, when viewed from the axial direction, the second suction side groove 33a and the first suction side groove 19a have approximately the same shape.

[0059] like Figure 3As shown, the second discharge side groove 33c is connected to the discharge hole 32b. Therefore, the interior of the second discharge side groove 33c is connected to the discharge outlet 32c via the discharge hole 32b. When viewed axially, the second discharge side groove 33c overlaps with the first discharge side groove 19c. Figure 4 and Figure 6 As shown, when viewed from the axial direction, the second discharge side groove 33c and the first discharge side groove 19c have approximately the same shape.

[0060] like Figure 5 and Figure 6 As shown, the protrusion 34 protrudes radially outward from the upper end of the radially outward-facing surface of the cover body 32. Viewed axially, the protrusion 34 is approximately trapezoidal with its long side radially inward and its short side radially outward. Viewed axially, the protrusion 34 overlaps with the first rib 20a. A positioning portion 34a is provided in the protrusion 34.

[0061] The positioning portion 34a is a hole recessed from the protrusion 34 on the upward side (the other side of the axial direction, i.e., the -Z side) and downward side (the other side of the axial direction, i.e., the +Z side). In this embodiment, the positioning portion 34a penetrates the protrusion 34 axially. The positioning portion 34a may also not penetrate the protrusion 34 axially. For example... Figure 6 As shown, in this embodiment, the positioning portion 34a opens radially outward. That is, the positioning portion 34a opens radially upward. The positioning portion 34a may also not open radially. For example... Figure 5 As shown, a portion of the first rib 20a on one axial side is located inside the positioning portion 34a. In this embodiment, the positioning portion 34a engages with the first rib 20a. Therefore, the circumferential positional accuracy of the pump cover 31 relative to the housing body 11 can be improved.

[0062] like Figure 3 As shown, the protruding cylindrical portion 35 protrudes downward from the lower end of the cover body portion 32. The protruding cylindrical portion 35 is generally cylindrical and extends axially about the rotation axis J. A fourth annular groove portion 35a is provided in the protruding cylindrical portion 35. The fourth annular groove portion 35a is a groove that is recessed radially inward from the radially outward surface of the protruding cylindrical portion 35 and extends circumferentially. The fourth annular groove portion 35a extends all around the circumference. An O-ring 92 is embedded inside the fourth annular groove portion 35a.

[0063] The metal housing portion 25 is housed inside the housing body portion 11. As described above, the metal housing portion 25 is fixed to the housing body portion 11. In this embodiment, the metal housing portion 25 is made of metal. Aluminum and stainless steel, etc., can be used as materials constituting the metal housing portion 25. As described above, in this embodiment, the housing body portion 11 is made of resin. Therefore, the coefficient of linear expansion of the metal housing portion 25 is smaller than that of the housing body portion 11. Figure 7As shown, the metal housing portion 25 has a peripheral wall portion 26, a top wall portion 27, and a cylindrical portion 29.

[0064] The peripheral wall portion 26 is a cylindrical shape extending axially. More specifically, the peripheral wall portion 26 is a generally cylindrical shape surrounding the axis of rotation J. Figure 4 As shown, when viewed axially, the center of the peripheral wall portion 26 is approximately aligned with the center of the inner peripheral surface 17a of the recess. Figure 3 As shown, the peripheral wall portion 26 has an opening on its lower side. The peripheral wall portion 26 is disposed inside the receiving recess 17. The peripheral wall portion 26 is fixed to the inner peripheral surface 17a of the recess. The peripheral wall portion 26 surrounds the pump portion 60 from the radially outer side. Radially, the peripheral wall portion 26 is disposed between the pump portion 60 and the inner peripheral surface 17a of the recess. The upper end of the peripheral wall portion 26 contacts the top surface 17e. Axially, the lower end of the peripheral wall portion 26 is positioned approximately at the same location as the lower end of the pump receiving portion 16.

[0065] like Figure 7 As shown, the top wall portion 27 is a generally annular plate extending radially. The top wall portion 27 is a plate extending radially outward from the lower side (+Z side) of the cylindrical portion 29. The top wall portion 27 surrounds the rotation axis J. The upper side (-Z side) of the peripheral wall portion 26 is circumferentially connected to the radially outward end of the top wall portion 27. Therefore, in this embodiment, the peripheral wall portion 26 and the top wall portion 27 are integrally formed, thus reducing the number of parts in the metal housing portion 25 compared to the case where the peripheral wall portion 26 and the top wall portion 27 are separate components. Therefore, the increase in manufacturing time for the electric oil pump 1 can be suppressed.

[0066] like Figure 3 As shown, the top wall portion 27 is disposed inside the receiving recess 17. That is, the top wall portion 27 is disposed inside the pump receiving portion 16. The top wall portion 27 is fixed to the top surface 17e. The top surface 17e is located above the top wall portion 27 and is axially opposed to the top wall portion 27. The downward-facing surface of the top wall portion 27 is located below the top surface 17e. Axially, the top wall portion 27 is disposed between the pump portion 60 and the top surface 17e. Figure 7 As shown, the top wall portion 27 is provided with a top wall through hole 28 and a second notch portion 27a.

[0067] The top wall through hole 28 is a hole that penetrates the top wall portion 27 axially. In this embodiment, two top wall through holes 28 are provided in the top wall portion 27. The two top wall through holes 28 include a first suction side through hole 28a and a first discharge side through hole 28c.

[0068] Viewed axially, the first intake-side through hole 28a and the first discharge-side through hole 28c are both approximately arc-shaped extending circumferentially. That is, the top wall through hole 28 is a hole extending circumferentially. The first intake-side through hole 28a and the first discharge-side through hole 28c are located at different positions circumferentially. The first intake-side through hole 28a and the first discharge-side through hole 28c are radially opposed. More specifically, the first intake-side through hole 28a and the first discharge-side through hole 28c are radially opposed across the rotation axis J.

[0069] like Figure 4 As shown, when viewed axially, the first suction-side through hole 28a surrounds the first suction-side groove 19a. Therefore, at least a portion of the first suction-side through hole 28a overlaps with the first suction-side groove 19a. That is, at least a portion of the top wall through hole 28a overlaps with the receiving groove 19. Thus, as... Figure 3 As shown, the interior of the first suction-side groove 19a is connected to the interior of the receiving recess 17 via the first suction-side through hole 28a. Furthermore, a portion of the top surface 17e is exposed on the lower side via the first suction-side through hole 28a.

[0070] like Figure 4 As shown, when viewed axially, the first discharge-side through hole 28c surrounds the first discharge-side groove 19c. Therefore, at least a portion of the first discharge-side through hole 28c overlaps with the first discharge-side groove 19c. That is, at least a portion of the top wall through hole 28c overlaps with the receiving groove 19. Thus, as... Figure 3 As shown, the interior of the first discharge-side groove 19c is connected to the interior of the receiving recess 17 via the first discharge-side through hole 28c. As described above, the interior of the first suction-side groove 19a is connected to the interior of the receiving recess 17 via the first suction-side through hole 28a. Thus, the interior of the receiving groove 19 is connected to the interior of the receiving recess 17 via the top wall through hole 28. Furthermore, a portion of the top surface 17e is exposed on its lower side via the first discharge-side through hole 28c.

[0071] like Figure 7 As shown, the second notch 27a is a notch that penetrates the top wall portion 27 axially. The second notch 27a extends radially. In this embodiment, one end of the second notch 27a, which is the radially outer end, is connected to the first discharge-side through hole 28c. That is, one end of the second notch 27a is connected to the top wall through hole 28c. It should be noted that the radially outer end of the second notch 27a may also be connected to the first suction-side through hole 28a. The other end of the second notch 27a, which is the radially inner end, reaches the radially inner edge of the top wall portion 27. Thus, the second notch 27a opens radially inward. Figure 3 and Figure 4As shown, when viewed axially, at least a portion of the communicating groove 18g of the annular wall portion 18 overlaps with the second notch 27a. Therefore, the interior of the receiving recess 17 is connected to the interior of the communicating groove 18g via the second notch 27a.

[0072] like Figure 7 As shown, the cylindrical portion 29 is a cylindrical shape extending upward from the radial inner edge of the top wall portion 27 to the opposite axial side (-Z side). More specifically, the top wall portion 27 is a generally cylindrical shape extending axially about the rotation axis J. Figure 3 As shown, the cylindrical portion 29 is disposed inside the connecting hole portion 18c. The rod body 43 passes through the cylindrical portion 29 axially. Radially, the cylindrical portion 29 is disposed between the rod body 43 and the inner circumferential surface of the connecting hole portion 18c. The cylindrical portion 29 supports the rod body 43 so that it can rotate about the rotation axis J. Therefore, direct contact between the rod body 43 and the resin-made connecting hole portion 18c can be suppressed, thus suppressing wear on the connecting hole portion 18c when the electric oil pump 1 is operated. Figure 7 As shown, a first notch 29a is provided in the cylindrical portion 29.

[0073] The first notch 29a is a notch that radially penetrates a portion of the circumferential direction of the cylindrical portion 29. The first notch 29a extends axially. The lower end of the first notch 29a reaches the lower end of the cylindrical portion 29. Thus, the first notch 29a is open on the lower side, i.e., on the axial side (+Z side). Therefore, as... Figure 3 As shown, the interior of the cylindrical portion 29 is connected to the interior of the receiving recess 17 via the first notch 29a. That is, the interior of the cylindrical portion 29 is connected to the interior of the pump receiving portion 16 via the first notch 29a.

[0074] like Figure 7 As shown, the other end of the second notch 27a, which is the radially inner end, is connected to the lower end of the first notch 29a. As described above, one end of the second notch 27a is connected to the first discharge-side through hole 28c. Furthermore, as described above, the interior of the first discharge-side groove 19c is connected to the interior of the receiving recess 17 via the first discharge-side through hole 28c. Thus, as... Figure 3 As shown, the interior of the cylindrical portion 29 is connected to the interior of the first discharge side groove portion 19c and the interior of the receiving recess 17 via the second notch portion 27a and the first notch portion 29a. Furthermore, as... Figure 4 As shown, the interior of the first notch 29a is connected to the interior of the connecting groove 18g. As described above, the connecting groove 18g connects the connecting hole 18c to the first discharge side groove 19c. Therefore, as... Figure 3 As shown, the interior of the cylindrical portion 29 is connected to the interior of the first discharge side groove 19c and the interior of the receiving recess 17 via the second notch portion 27a, the connecting groove portion 18g and the first notch portion 29a.

[0075] like Figure 8 As shown, the base plate 37 is a generally annular plate that extends radially. The base plate 37 surrounds the axis of rotation J. Figure 3 As shown, the base plate 37 is fixed to the surface of the pump housing 31 facing upwards, i.e., the other side (-Z side) axially. The base plate 37 is positioned lower than the pump portion 60. The base plate 37 and the pump portion 60 are axially opposed. In this embodiment, the base plate 37 contacts the peripheral wall portion 26 of the metal housing portion 25 axially. Therefore, direct contact between the inner rotor 61 and the outer rotor 62 and the resin pump housing 31 can be prevented. The base plate 37 may also be axially spaced apart from the peripheral wall portion 26. The radially outer end of the base plate 37 is located radially outer than the peripheral wall portion 26. In this embodiment, the base plate 37 is made of metal. Aluminum and stainless steel, etc., can be used as materials constituting the base plate 37. Figure 8 As shown, the base plate 37 is provided with multiple holes 37a and a through hole 38.

[0076] Each hole 37a is an axially penetrating hole through the base plate portion 37. In this embodiment, six holes 37a are provided in the base plate portion 37. The holes 37a are arranged at approximately equal intervals along the circumference. Although not shown in the figure, a portion of the pump cover 31 enters the interior of each hole 37a. Therefore, radial and circumferential positional variations of the base plate portion 37 relative to the pump cover 31 can be appropriately suppressed, and the holding force of the pump cover 31 in retaining the base plate portion 37 can be improved.

[0077] The bottom plate through hole 38 is a hole that penetrates the bottom plate portion 37 axially. In this embodiment, two bottom plate through holes 38 are provided in the bottom plate portion 37. The two bottom plate through holes 38 include a second suction side through hole 38a and a second discharge side through hole 38c.

[0078] Viewed axially, the second intake-side through hole 38a and the second discharge-side through hole 38c are both approximately arc-shaped extending circumferentially. That is, the bottom plate through hole 38 is a hole extending circumferentially. The second intake-side through hole 38a and the second discharge-side through hole 38c are located at different positions circumferentially. The second intake-side through hole 38a and the second discharge-side through hole 38c are radially opposed. More specifically, the second intake-side through hole 38a and the second discharge-side through hole 38c are radially opposed across the rotation axis J.

[0079] like Figure 6 As shown, when viewed axially, the second suction-side through hole 38a surrounds the second suction-side groove 33a. Therefore, at least a portion of the second suction-side through hole 38a overlaps with the second suction-side groove 33a. That is, at least a portion of the bottom plate through hole 38a overlaps with the cover groove 33. Thus, as... Figure 3 As shown, the interior of the second suction side groove 33a is connected to the interior of the receiving recess 17 via the second suction side through hole 38a.

[0080] like Figure 6 As shown, when viewed axially, the second discharge-side through hole 38c surrounds the second discharge-side groove 33c. Therefore, at least a portion of the second discharge-side through hole 38c overlaps with the second discharge-side groove 33c. That is, at least a portion of the bottom plate through hole 38c overlaps with the cover groove 33. Therefore, as... Figure 3 As shown, the interior of the second discharge-side groove 33c is connected to the interior of the receiving recess 17 via the second discharge-side through hole 38c. As described above, the interior of the second suction-side groove 33a is connected to the interior of the receiving recess 17 via the second suction-side through hole 38a. Therefore, the interior of the cover groove 33 is connected to the interior of the receiving recess 17 via the bottom plate through hole 38.

[0081] like Figure 2 As shown, the motor unit 40 is housed inside the housing body 11. More specifically, the motor unit 40 is housed inside the motor housing 12. Axially, the motor unit 40 is positioned below the control device 56 and above the pump unit 60. The motor unit 40 has a rotor 41 and a stator 50.

[0082] The rotor 41 is rotatable. In this embodiment, the rotor 41 can rotate about the rotation axis J. The rotor 41 can also rotate about an imaginary axis extending axially, different from the rotation axis J. The rotor 41 has a rotor core 41a and a magnet 41b. The rotor core 41a is approximately annular about the rotation axis J. The magnet 41b is fixed to the rotor core 41a.

[0083] The stator 50 is positioned radially outward from the rotor 41. The stator 50 and rotor 41 are radially opposed by a gap. As described above, in this embodiment, the stator 50 is embedded inside the stator holding portion 12g. Therefore, the housing body portion 11 holds the stator 50. The stator 50 has a stator core 51, an insulator 52, and a coil portion 53.

[0084] The stator core 51 surrounds the rotor core 41a radially outward. The stator core 51 has a generally annular core back 51a and a plurality of teeth 51b protruding radially inward from the inner circumference of the core back 51a. Although not shown in the figure, the plurality of teeth 51b are arranged at circumferential intervals. A coil portion 53 is mounted on the teeth 51b, separated by an insulating member 52. The coil portion 53 is composed of wound coil wire. Although not shown in the figure, the coil portion 53 is electrically connected to a control device 56. Current is supplied to the coil portion 53 from the control device 56.

[0085] The rod body 43 is a generally cylindrical shape extending axially. In this embodiment, the rod body 43 is a generally cylindrical shape extending axially about the rotation axis J. The rod body 43 may also extend axially about an imaginary axis extending axially, different from the rotation axis J. The rod body 43 extends across the motor housing 12 and the pump housing 16. The upper portion of the rod body 43 is disposed inside the motor housing 12. The upper portion of the rod body 43 passes axially through the interior of the rotor core 41a. The rotor core 41a is fixed to the outer peripheral surface of the rod body 43. That is, the rotor 41 is fixed to the rod body 43. Therefore, the rod body 43 can rotate together with the rotor 41. The axially central portion of the rod body 43 passes axially through the interior of the communicating hole 18c of the housing body 11 and the interior of the cylindrical portion 29 of the metal housing 25. As described above, the cylindrical portion 29 is disposed between the inner peripheral surface of the rod body 43 and the communicating hole 18c. The rod body 43 is supported by the cylindrical portion 29 so that it can rotate about the rotation axis J. The lower part of the rod body 43 is disposed inside the pump housing 16. The lower part of the rod body 43 is connected to the pump section 60. Thus, the rotational torque of the rotor 41 is transmitted to the pump section 60 via the rod body 43.

[0086] The control device 56 generates a current that is supplied to the coil section 53, and supplies this current to the coil section 53. Therefore, the control device 56 controls the operation of the electric oil pump 1. The control device 56 has a circuit board 57.

[0087] The circuit board 57 is a plate-shaped structure extending in a direction orthogonal to the axial direction. The circuit board 57 is held in multiple board holding portions 12h within the main housing 11. Multiple electronic components are mounted on the circuit board 57. These components include multiple power semiconductor devices such as Insulated Gate Bipolar Transistors (IGBTs) and Metal-Oxide-Semiconductor Field-Effect Transistors (MOSFETs), multiple capacitors, and multiple resistors. The circuit board 57 is electrically connected to an external power supply (not shown) and a coil section 53, respectively. The circuit board 57 generates a current with a predetermined waveform based on the current supplied by the external power supply and supplies this current to the coil section 53. When current is supplied to the coil section 53, the rotor 41 and the rod 43 rotate around the rotation axis J.

[0088] The pump section 60 is housed inside the housing body 11. More specifically, the pump section 60 is housed inside the pump housing 16. Furthermore, the pump section 60 is housed inside the metal housing 25. As described above, the peripheral wall 26 surrounds the pump section 60 radially outward. The top wall 27 is axially opposed to the pump section 60. The pump section 60 is connected to the lower side (+Z side) of the rod body 43. The pump section 60 is driven by the motor 40 to draw oil from the outside of the electric oil pump 1, compresses the drawn oil, and discharges it to the outside of the electric oil pump 1. The pump section 60 is driven by the motor 40 to pressurize and deliver oil. The pump section 60 in this embodiment is a cycloidal pump. In this embodiment, the pump section 60 is made of metal. The pump section 60 has an inner rotor 61 and an outer rotor 62.

[0089] The inner rotor 61 extends axially and is annular when viewed axially. The lower portion of the rod 43 is inserted inside the inner rotor 61. The rod 43 is fixed to the inner circumferential surface of the inner rotor 61. That is, the inner rotor 61 is connected to the lower side of the rod 43, i.e., the axial side (+Z side). The power of the rotor 41 is transmitted to the inner rotor 61. Therefore, the inner rotor 61 can rotate about the rotation axis J. Furthermore, the inner circumferential surface of the inner rotor 61 and the rod 43 do not need to be firmly fixed. The inner circumferential surface (inner diameter) of the inner rotor 61 and the outer diameter of the rod 43 can each have a flat portion through machining. Alternatively, the flat portion of the inner circumferential surface (inner diameter) of the inner rotor 61 can be opposite the flat portion of the outer diameter of the rod 43, and the inner circumferential surface (inner diameter) of the inner rotor 61 and the rod 43 can be inserted with a clearance fit. With this configuration, the assembly of the inner rotor 61 and the rod 43 is easy, and the power of the rotor 41 is transmitted to the inner rotor 61. Furthermore, by using a stop ring, the relative axial positional shift between the inner rotor 61 and the rod body 43 can be suppressed.

[0090] The outer rotor 62 is positioned radially outward from the inner rotor 61. The outer rotor 62 is annular, surrounding the inner rotor 61 radially outward. A gap is provided between the outer rotor 62 and the peripheral wall portion 26. The outer peripheral surface of the outer rotor 62 can partially contact the inner peripheral surface of the peripheral wall portion 26. When the electric oil pump 1 is operated, oil is trapped between the outer rotor 62 and the peripheral wall portion 26.

[0091] like Figure 9 As shown, the inner rotor 61 and the outer rotor 62 each have cycloidal teeth. The inner rotor 61 has multiple external teeth 61a protruding radially outward. The outer rotor 62 protrudes radially inward and has multiple internal teeth 62a that mesh with the external teeth 61a. When the inner rotor 61 rotates integrally with the rod body 43 about the rotation axis J, the outer rotor 62 slides on the inner circumferential surface of the peripheral wall portion 26 while rotating eccentrically about the rotation axis J.

[0092] like Figure 3As shown, the interior of the second suction-side groove 33a and the interior of the first suction-side groove 19a are axially connected via the gap G between the inner rotor 61 and the outer rotor 62, the first suction-side through hole 28a, and the second suction-side through hole 38a. In the following description, the internal space of the interconnected second suction-side groove 33a, the gap G, and the internal space of the first suction-side groove 19a are referred to as the suction chamber A1. The suction chamber A1 is connected to the suction port 32a.

[0093] The interior of the second discharge side groove 33c is axially connected to the interior of the first discharge side groove 19c via the gap G between the inner rotor 61 and the outer rotor 62, the first discharge side through hole 28c, and the second discharge side through hole 38c. In the following description, the internal space of the interconnected second discharge side groove 33c, the gap G, and the internal space of the first discharge side groove 19c are referred to as compression chamber A2. Compression chamber A2 is connected to discharge outlet 32c via discharge hole 32b.

[0094] When the electric oil pump 1 operates, the gap G between the inner rotor 61 and the outer rotor 62 moves around the rotation axis J due to the rotation of the inner rotor 61 and the outer rotor 62. Therefore, when the pressure in the suction chamber A1 decreases, as... Figure 3 As indicated by arrow F1, oil flows into the suction chamber A1 through the suction port 32a. More specifically, although not shown in the diagram, the oil flowing into the second suction-side groove 33a through the suction port 32a flows circumferentially inside the second suction-side groove 33a and is drawn into the gap G through the second suction-side through hole 38a. A portion of the oil drawn into the gap G flows into the first suction-side groove 19a through the first suction-side through hole 28a. The oil flowing into the first suction-side groove 19a flows circumferentially inside the first suction-side groove 19a and is again drawn into the gap G.

[0095] When the inner rotor 61 and outer rotor 62 rotate, and the gap G moves circumferentially, as... Figure 3As indicated by arrow F2, oil moves from the suction chamber A1 to the compression chamber A2. Although not shown in the diagram, a portion of the oil drawn into gap G flows into the first discharge side groove 19c via the first discharge side through-hole 28c. As described above, a portion of the oil drawn in from the suction port 32a flows into the first suction side groove 19a via the first suction side through-hole 28a. Thus, the oil pumped by the pump section 60 passes through the top wall through-hole 28. The oil flowing into the first discharge side groove 19c flows circumferentially inside the first discharge side groove 19c and is again drawn into gap G. As described above, the oil flowing into the first suction side groove 19a flows circumferentially inside the first suction side groove 19a. Thus, the oil pumped by the pump section 60 flows inside the receiving groove 19. The oil drawn into gap G flows into the second discharge side groove 33c via the second discharge side through-hole 38c. The oil flowing into the second discharge side groove 33c flows circumferentially inside the second discharge side groove 33c. Therefore, when the pressure of the oil in compression chamber A2 increases, such as Figure 3 As indicated by arrow F3, the oil in the compression chamber A2 is pumped to the outside of the electric oil pump 1 via the discharge port 32b and the discharge outlet 32c. Therefore, the electric oil pump 1 supplies oil to the mounted body (not shown).

[0096] As described above, in this embodiment, oil flows into the interiors of the first suction-side groove 19a and the second suction-side groove 33a in the suction chamber A1. Therefore, the pump unit 60 is subjected to a downward force on the oil inside the first suction-side groove 19a and an upward force on the oil inside the second suction-side groove 33a. Furthermore, in this embodiment, oil flows into the interiors of the first discharge-side groove 19c and the second discharge-side groove 33c in the compression chamber A2. Therefore, the pump unit 60 is subjected to a downward force on the oil inside the first discharge-side groove 19c and an upward force on the oil inside the second discharge-side groove 33c. That is, the pump unit 60 is subjected to a downward force on the oil inside the receiving groove 19 and an upward force on the oil inside the cover groove 33. Therefore, in this embodiment, the pump unit 60 can rotate while oil forces are applied to it from both axial sides. Therefore, when the electric oil pump 1 is activated, it can suppress the vibration of the inner rotor 61 and the outer rotor 62.

[0097] As described above, the interior of the cylindrical portion 29 is connected to the interior of the pump receiving portion 16 via the first notch 29a. Furthermore, the interior of the cylindrical portion 29 is connected to the interior of the receiving recess 17 via the second notch 27a, the first notch 29a, and the top wall through hole 28. Moreover, as described above, the interior of the cylindrical portion 29 is connected to the interior of the first discharge side groove 19c and the interior of the receiving recess 17 via the second notch 27a, the communicating groove 18g, and the first notch 29a. Therefore, as... Figure 3As indicated by arrow F4, a portion of the oil drawn into gap G and a portion of the oil inside the first discharge side groove 19c flow into the interior of the cylindrical portion 29, flowing upwards between the rod body 43 and the cylindrical portion 29. Therefore, oil can be supplied between the rod body 43 and the cylindrical portion 29. Figure 3 As indicated by arrow F4, oil flowing upwards between the rod body 43 and the cylindrical portion 29 flows into the motor housing 12. Therefore, in this embodiment, oil can be supplied to the interior of the motor housing 12.

[0098] As described above, in this embodiment, the second notch 27a and the connecting groove 18g are respectively connected to the first discharge side groove 19c. Furthermore, as described above, the oil pressure in the compression chamber A2 is high. Therefore, in this embodiment, oil pressurized by the pump 60 can be supplied to the interior of the cylindrical portion 29, thus increasing the flow rate of oil into the cylindrical portion 29. Therefore, the rod body 43 and the cylindrical portion 29 can be properly lubricated by the oil, and the amount of oil flowing into the motor housing 12 can be increased. It should be noted that the second notch 27a and the connecting groove 18g can also be connected to the first suction side groove 19a. Even in this case, oil can flow from the first suction side groove 19a into the interior of the cylindrical portion 29, thus lubricating the rod body 43 and the cylindrical portion 29, and supplying oil to the motor housing 12. That is, the second notch 27a and the connecting groove 18g are respectively connected to the receiving groove 19, thereby enabling the rod body 43 and the cylindrical part 29 to be lubricated by oil, and enabling oil to be supplied to the motor receiving part 12.

[0099] The oil flowing into the motor housing 12 circulates within the motor housing 12 due to the rotation of the rotor 41, cooling both the motor unit 40 and the control device 56. Therefore, it prevents the temperatures of the motor unit 40 and the control device 56 from becoming excessively high, thereby improving the stability of their operation.

[0100] As described above, the outlet hole 18e connects the interior of the motor housing 12 to the interior of the first suction side groove 19a. Therefore, when the electric oil pump 1 operates, when the pressure in the suction chamber A1 decreases, as... Figure 3 As indicated by arrow F5, a portion of the oil circulating inside the motor housing 12 flows into the first suction side groove 19a via the outlet 18e. The oil flowing into the first suction side groove 19a, together with the oil flowing into the suction chamber A1 from the suction port 32a, is pumped to the outside of the electric oil pump 1 via the outlet 32c.

[0101] According to this embodiment, the electric oil pump 1 includes: a rod body 43 extending axially; a motor part 40 having a rotor 41 fixed to the rod body 43 and rotatable; a pump part 60 driven by the power of the motor part 40 to pressurize and deliver oil; and a housing 10 housing the motor part 40 and the pump part 60. The pump part 60 has: an inner rotor 61 connected to the lower side of the rod body 43, i.e., the axial side (+Z side), having external teeth 61a; and an outer rotor 62 surrounding the inner rotor 61 from the radially outer side, having internal teeth 62a that mesh with the external teeth 61a. The housing 10 has a resin-made housing body 11 and a metal-made metal housing 25. The housing body 11 includes a motor housing 12 for housing a motor 40, a pump housing 16 for housing a pump 60, and a connecting hole 18c connecting the interior of the motor housing 12 and the interior of the pump housing 16 for the rod 43 to pass through axially. The metal housing 25 has an axially extending cylindrical portion 29, which is radially disposed between the inner circumferential surface of the rod 43 and the connecting hole 18c. Therefore, in this embodiment, the housing body 11 is made of resin, thus reducing the volume of metal material constituting the housing 10 compared to a metal housing body 11. The resin-made housing body 11 also appropriately reduces the cost of the housing 10 and makes it lightweight. However, when the main body 11 of the housing is made of resin, when the rod 43 is supported and rotatable by the inner circumferential surface of the connecting hole 18c, the inner circumferential surface of the connecting hole 18c is easily worn due to friction with the rod 43 during operation of the electric oil pump 1, which may reduce the durability of the electric oil pump 1. To address this technical problem of the electric oil pump 1, in this embodiment, as described above, a cylindrical portion 29 is disposed radially between the rod 43 and the inner circumferential surface of the connecting hole 18c, thus allowing the rod 43 to be supported and rotatable by the metal cylindrical portion 29. Because the rod 43 can be supported and rotatable by the metal cylindrical portion 29, direct contact between the rod 43 and the resin connecting hole 18c can be suppressed, as described above. Therefore, wear of the connecting hole 18c due to friction with the rod 43 can be suppressed during operation of the electric oil pump 1. Therefore, the electric oil pump 1 can be made lighter, and the reduction in the durability of the electric oil pump 1 can be appropriately suppressed.

[0102] In this embodiment, as described above, the rod body 43 is supported by the cylindrical portion 29, thus stabilizing the rotation of the rod body 43. Therefore, the rotation of the inner rotor 61 and the outer rotor 62 can be stabilized. Therefore, the discharge rate of oil from the pump section 60 can be appropriately stabilized.

[0103] According to this embodiment, a first notch 29a is provided in the cylindrical portion 29. This first notch 29a radially penetrates a portion of the circumferential direction of the cylindrical portion 29 and opens on the lower side, i.e., the axial side (+Z side). The interior of the cylindrical portion 29 is connected to the interior of the pump housing 16 via the first notch 29a. Thus, a portion of the oil pumped by the pump 60 flows into the interior of the cylindrical portion 29 via the first notch 29a and flows upward between the rod 43 and the cylindrical portion 29. Therefore, oil can be supplied between the rod 43 and the cylindrical portion 29. Therefore, the rod 43 and the cylindrical portion 29 can be properly lubricated by oil, thereby suppressing friction between the rod 43 and the cylindrical portion 29. Therefore, the durability of the electric oil pump 1 can be improved more appropriately. Moreover, the friction between the rod 43 and the cylindrical portion 29 can be suppressed, thereby suppressing heat generation in the rod 43 and the cylindrical portion 29.

[0104] In this embodiment, as described above, the friction between the rod body 43 and the cylindrical portion 29 can be reduced, thus stabilizing the rotational speed of the rod body 43. Therefore, the rotational speeds of the inner rotor 61 and the outer rotor 62 can be appropriately stabilized. Consequently, the amount of oil discharged from the pump section 60 can be more appropriately stabilized.

[0105] According to this embodiment, the metal housing portion 25 is a plate-shaped portion extending radially outward from the lower side (+Z side) of the cylindrical portion 29, and has a top wall portion 27 disposed inside the pump housing portion 16. The top wall portion 27 is provided with: a top wall through hole 28 that axially penetrates the top wall portion 27 and through which oil pumped by the pump portion 60 passes; and a second notch portion 27a that axially penetrates the top wall portion 27. One end of the second notch portion 27a is connected to the top wall through hole 28, and the other end is connected to the first notch portion 29a. Thus, as described above, the interior of the cylindrical portion 29 is connected to the interior of the pump housing portion 16 via the top wall through hole 28, the second notch portion 27a, and the first notch portion 29a. Therefore, a portion of the oil pumped by the pump portion 60 flows into the interior of the cylindrical portion 29 via the top wall through hole 28, the second notch portion 27a, and the first notch portion 29a. Therefore, the flow rate of oil supplied between the shaft 43 and the cylindrical portion 29 can be appropriately increased. This allows for more appropriate lubrication of the shaft 43 and the cylindrical portion 29, thus reducing the friction between them. Consequently, the durability of the electric oil pump 1 can be improved more effectively.

[0106] According to this embodiment, the pump housing 16 has a top surface 17e, which is located above the top wall 27, i.e., on the other side (-Z side) axially, and is axially opposite to the top wall 27. The top surface 17e provides: a receiving groove 19, recessed upwards, for the flow of oil pressurized by the pump 60; and a connecting groove 18g, recessed upwards, connecting the receiving groove 19 to the connecting hole 18c. When viewed axially, at least a portion of the connecting groove 18g overlaps with the second notch 27a. Thus, the interior of the cylindrical portion 29 is connected to the interior of the receiving groove 19 via the second notch 27a, the first notch 29a, and the connecting groove 18g. Therefore, as described above, oil pressurized by the pump 60 can be supplied to the interior of the cylindrical portion 29 via the second notch 27a, the first notch 29a, and the connecting groove 18g, thereby more appropriately increasing the flow rate of oil supplied between the rod 43 and the cylindrical portion 29. Therefore, the shaft 43 and the cylindrical portion 29 can be lubricated more appropriately with oil, thus reducing the friction between the shaft 43 and the cylindrical portion 29 more effectively. Consequently, the durability of the electric oil pump 1 can be improved more effectively.

[0107] The embodiments of the present invention have been described above. However, the various components and combinations thereof in the embodiments are merely examples, and additions, omissions, substitutions, and other modifications can be made to the components without departing from the spirit of the present invention. Furthermore, the scope of the present invention is not limited by the embodiments.

[0108] The pump housing can also be made of metal. Even in this case, since the main body of the housing is made of resin, the housing can be made lightweight. Therefore, the electric oil pump can be made lightweight. Furthermore, in this case, the housing may not have a base plate.

[0109] The metal casing can also be fixed to the main casing using adhesives or the like. Even in this case, wear on the main casing can be suppressed by the peripheral wall, top wall, and cylindrical portion, respectively. Furthermore, the base plate can also be fixed to the pump cover using adhesives or the like. Even in this case, wear on the pump cover can be suppressed by the base plate.

[0110] The application of the electric oil pump of the present invention is not particularly limited. The type of fluid transported by the electric oil pump is not particularly limited; it can be a liquid other than oil, such as water. The electric oil pump can also be mounted on an installation body other than a vehicle. It should be noted that the various components described above can be appropriately combined without contradiction.

Claims

1. An electric oil pump, comprising: The shaft extends axially; The motor section has a rotor that is fixed to the rod body and can rotate; The pump unit, driven by the power of the motor unit, pressurizes and delivers oil; and Housing that houses the motor section and the pump section. The pump unit has: An inner rotor, connected to one axial side of the rod body, has external teeth; and An outer rotor, surrounding the inner rotor radially outward, has internal teeth that mesh with the outer teeth. The shell has a resin-made shell body and a metal-made metal shell body. The main body of the housing has: Motor housing, which houses the motor unit; Pump housing, accommodating the pump unit; as well as A connecting hole connects the interior of the motor housing to the interior of the pump housing, allowing the rod to pass through axially. The metal housing portion has a cylindrical portion extending axially. In the radial direction, the cylindrical portion is disposed between the inner circumferential surface of the rod body and the communicating hole portion.

2. The electric oil pump according to claim 1, wherein, The cylindrical portion has a first notch that extends radially through a portion of the circumference of the cylindrical portion and is open on one axial side. The interior of the cylindrical section is connected to the interior of the pump housing via the first notch.

3. The electric oil pump according to claim 2, wherein, The metal housing portion is a plate-shaped part that extends radially outward from one end of the cylindrical portion along its axial direction, and has a top wall portion disposed inside the pump housing portion. The top wall portion is provided with: A through hole in the top wall extends axially through the top wall portion and allows the oil pumped by the pump to pass through; and The second notch extends axially through the top wall. One end of the second notch is connected to the through hole in the top wall, and the other end of the second notch is connected to the first notch.

4. The electric oil pump according to claim 3, wherein, The pump housing is located on the opposite side of the top wall portion along the axial direction, and has a top surface that is axially opposite the top wall portion. The top surface is provided with: The receiving groove is recessed to the other side axially to allow the oil pumped by the pump to flow; and The connecting groove is recessed to the other side axially, connecting the receiving groove to the connecting hole. When viewed from the axial direction, at least a portion of the connecting groove overlaps with the second notch.

5. The electric oil pump according to any one of claims 1 to 4, wherein, The main body of the housing is formed by embedding the metal housing part as an embedded member.

Images