Pump device

Abstract

This pump device (1) comprises: a shaft (47); a rotor (72) rotatably supported by the shaft (47); a housing (2) that accommodates the rotor (72); a stator (8) fixed to the housing (2); a base (6) that supports the shaft (47); and an electronic component (91) that generates heat. The base (6) has a greater thermal conductivity than the housing (2), and the electronic component (91) is in contact with the base (6).

Description

Pump device

[0001] The present invention relates to a pump device.

[0002] For example, Patent Document 1 discloses an electric pump for pumping a coolant inside an engine or the like of a vehicle. This electric pump incorporates a circuit element that controls the supply of current to a coil.

[0003] Japanese Patent No. 6047023

[0004] The heat generated by the circuit element is transmitted to the motor housing via a circuit board or a heat dissipation sheet on which the circuit element is mounted. For example, an increase in heat generation of the circuit element is expected in the case of increasing the output of the electric pump, so further cooling measures are required.

[0005] The present invention has been made in view of the above problems, and one of the problems is to provide a pump device capable of efficiently conducting heat from electronic components.

[0006] A pump device according to an aspect of the present invention includes a shaft, a rotor rotatably supported by the shaft, a housing that houses the rotor, a stator fixed to the housing, a base that supports the shaft, and an electronic component that generates heat. The base has higher thermal conductivity than the housing, and the electronic component is in contact with the base.

[0007] This is a schematic perspective view showing the structure of a pump device 1 according to one embodiment of the present invention. This is a schematic perspective view showing the structure of a pump device 1 according to one embodiment of the present invention. This is a cross-sectional view along line 3-3 in Figure 1. This is a cross-sectional view along line 4-4 in Figure 3. This is a schematic perspective view showing the structure of a base 6 according to one specific example. This is a schematic perspective view showing the structure of a base 6 according to one specific example. This is a cross-sectional view of the base 6 along line 7-7 in Figure 6. This is a partially enlarged perspective cross-sectional view showing a schematic part of the structure of a pump device 1. This is a cross-sectional view along line 9-9 in Figure 3. This is a partially enlarged cross-sectional view for explaining the heat conduction path. This is a partially enlarged cross-sectional view showing the structure of a pump device 1A according to another embodiment of the present invention. This is a cross-sectional view along line 12-12 in Figure 11. This is an exploded perspective view showing the structure of a base 10, a gasket 64, a cap 11, and a heat conduction member 94. This is an exploded perspective view showing the structure of a base 10, a gasket 64, a cap 11, and a heat conduction member 94. This is a partially enlarged cross-sectional view showing the structure of a pump device 1B according to yet another embodiment of the present invention. This is a cross-sectional view along line 16-16 in Figure 15. This is an exploded perspective view showing the structure of the base 10A, gaskets 66 and 67, cap 11A, and heat conductive member 94 in general.

[0008] Hereinafter, an embodiment of the present invention will be described with reference to the attached drawings. Figures 1 and 2 are schematic perspective views showing the structure of a pump device 1 according to an embodiment of the present invention. This pump device 1 is, for example, a water pump. A water pump is a centrifugal pump for transferring (pressurizing) a fluid, i.e., a coolant. The pump device 1 is installed, for example, in the engine room or motor room of a vehicle. The pump device 1 is used, for example, to cool a drive source such as the engine or motor of a vehicle by transferring coolant to the drive source.

[0009] In pump device 1, the direction along axis x is defined as the axial direction. In this axial direction, one side is defined as the upper side and the other side as the lower side. The upper and lower sides do not necessarily coincide with the upper and lower sides in the direction of gravity. Furthermore, the direction perpendicular to axis x is defined as the radial direction. In the radial direction, the direction approaching axis x is defined as the inner circumference side and the direction moving away from axis x is defined as the outer circumference side. In addition, a circumferential direction is defined around axis x. The clockwise and counterclockwise directions in the circumferential direction are defined as the direction when viewed from the upper side in the axial direction.

[0010] Figure 1 is a perspective view of the pump device 1 seen from above in the axial direction, and Figure 2 is a perspective view of the pump device 1 seen from below in the axial direction. Referring to both Figures 1 and 2, the pump device 1 includes a housing 2 that is formed in a generally cylindrical shape with axis x as the center. The housing 2 has a case 3, a can portion 4, and a cover 5 arranged in order from top to bottom along axis x. The case 3 and the can portion 4 are formed by injection molding from a thermoplastic resin material, such as PPS (polyphenylene sulfide), for example. The cover 5 is formed from a metal material, such as aluminum, with some exceptions. The internal space of the housing 2 is defined by the case 3 and the can portion 4.

[0011] Case 3 comprises a main body 31 and an inlet 32 ​​and an outlet 33 integrally formed on the main body 31. The main body 31 is formed, for example, as a flat cylindrical shape with the top closed. The inlet 32 ​​protrudes upward from the upper surface of the main body 31 along the axis x. The inlet 32 ​​is formed, for example, as a cylindrical shape centered on the axis x. The inlet 32 ​​allows fluid to flow into the internal space of the housing 2. The outlet 33 protrudes outward from the main body 31 along the tangent to a virtual circle centered on the axis x. The outlet 33 is formed, for example, as a cylindrical shape centered on the tangent. The outlet 33 allows fluid to flow out from the internal space of the housing 2.

[0012] The can portion 4 is formed as a whole, for example, in a cylindrical shape. The case 3 is attached to the upper end of the can portion 4, while the cover 5 is attached to the lower end of the can portion 4. Fixing members (not shown), such as screws, are used to attach the case 3 and cover 5 to the can portion 4. The cover 5 has a main body 51, a plurality of fins 52, and a connector housing 53. The main body 51 is formed, for example, in a flat cylindrical shape with the lower side closed. The plurality of fins 52 protrude downward from the lower surface 51a of the main body 51 in an axial direction parallel to each other. The plurality of fins 52 spread out parallel to each other. The main body 51 and the fins 52 are integrally formed from a thermally conductive metal material, such as aluminum.

[0013] The connector housing 53 is attached to the lower surface 51a of the main body 51 by fixing members 54, such as screws. The connector housing 53 is formed in a cylindrical shape, for example, extending downward parallel to the axial direction. As will be described later, one or more connector pins (not visible in Figure 2) are housed inside the connector housing 53. The connector pins protrude downward from the main body 51 inside the connector housing 53. Connectors (not shown) of external devices are connected to the connector pins. In this way, power and signals are supplied from the external device to the pump device 1 via the connector pins. The connector housing 53 is formed from, for example, an insulating resin material. However, it is not limited to this; the main body 51, fins 52, and connector housing 53 may be integrally formed from a resin material that has thermal conductivity.

[0014] Figure 3 is a cross-sectional view along line 3-3 in Figure 1. As shown in Figure 3, the can portion 4 has a bottom wall 41, an inner wall 42, a top wall 43, and an outer wall 44. The bottom wall 41 is formed, for example, in the shape of a flat disc perpendicular to the axis x. The inner wall 42 extends upward from the outer edge of the bottom wall 41. The inner wall 42 is formed in the shape of a cylinder centered on the axis x. The top wall 43 extends outward from the upper edge of the inner wall 42. The top wall 43 is formed in the shape of an annular ring centered on the axis x. The outer wall 44 extends downward from the outer edge of the top wall 43. The outer wall 44 is formed in the shape of a cylinder centered on the axis x.

[0015] The can section 4 further has a flange 45 that extends radially outward in an annular shape adjacent to the upper end of the outer wall 44. An annular groove 46 is formed on the upper surface of the flange 45. The groove 46 is recessed downward in the axial direction from the upper surface of the flange 45. An elastic member such as an annular O-ring, i.e., a gasket 47, is placed in this groove 46. The annular lower surface of the main body 31 of the case 3 is received by the upper surface of the flange 45 of the can section 4. As the lower surface of the main body 31 is pressed against the upper surface of the flange 45 in this way, the gasket 47 is crushed in the groove 46. As a result, the space between the main body 31 of the case 3 and the flange 45 of the can section 4 is sealed, preventing fluid from leaking to the outside of the pump device 1.

[0016] An internal space S is formed within the housing 2 by the case 3 and the can section 4. The internal space S has a first space S1 formed by the main body 31 of the case 3 and the top wall 43 of the can section 4, and a second space S2 formed by the bottom wall 41 and the inner wall 42 of the can section 4. In this example, both the first space S1 and the second space S2 are generally cylindrical spaces centered on axis x. The first space S1 and the second space S2 are in communication with each other. In the radial direction, the diameter of the first space S1 is larger than the diameter of the second space S2. On the other hand, in the axial direction, the height of the first space S1 is smaller than the height of the second space S2.

[0017] Case 3 includes a support portion 34 located within the main body 31 below the lower base end of the inlet portion 32, and a plurality of spokes 35 supporting the support portion 34. In this example, the support portion 34 is positioned to enter the first space S1 from the lower end of the inlet portion 32 along the axis x. The support portion 34 as a whole is formed in a generally conical shape centered on the axis x. The plurality of spokes 35 connect the outer surface of the support portion 34 and the inner surface of the inlet portion 32 to each other. In this example, three spokes 35 are arranged at predetermined intervals in the circumferential direction. Each spoke 35 is formed in a flat plate shape extending, for example, along a virtual plane containing the axis x.

[0018] The housing 2 has a base 6 attached to the bottom wall 41 of the can section 4. The base 6 has a cylindrical base body 61 centered on axis x. The base body 61 is attached to a through hole 41a that penetrates the bottom wall 41 along axis x. A shaft 48 is arranged in the internal space S of the housing 2. The shaft 48 is formed, for example, in a cylindrical shape centered on axis x. The upper end of the shaft 48 is fixed to a recess 34a formed on the lower surface of the support section 34 of the case 3. On the other hand, the lower end of the shaft 48 is fixed to a through hole 62 that penetrates the base body 61 along axis x. For fixing, the lower end of the shaft 48 is, for example, press-fitted into the through hole 62.

[0019] The pump device 1 includes a rotating body 7 rotatably supported on a shaft 48 about an axis x. The rotating body 7 has a bearing 71 supported on the shaft 48 and a rotor 72 fixed to the bearing 71. The bearing 71 is formed in a cylindrical shape along the axis x. The inner circumferential surface of the bearing 71 faces the outer circumferential surface of the shaft 48 with a predetermined gap between them. Thus, the bearing 71 is configured to be rotatable about the axis x and to be movable in the vertical direction along the axis x. The bearing 71 is a so-called sliding bearing. The rotor 72 has an impeller body 73 fixed to the bearing 71 and a magnet 74 fixed to the impeller body 73.

[0020] The impeller body 73 comprises a cylinder 75, a first flange 76, a plurality of blades 77, and a second flange 78. The impeller body 73 is integrally formed by injection molding from a thermoplastic resin material, such as PPS (polyphenylene sulfide). The cylinder 75 is formed in a cylindrical shape with axis x as the center. The first flange 76 extends radially in an annular shape from the upper end of the cylinder 75 in the axial direction. That is, the first flange 76 is formed in a disc shape with axis x as the center. On the other hand, the second flange 78 extends radially in an annular shape from the cylinder 75 between the upper and lower ends of the cylinder 75 in the axial direction. In the axial direction, the lower surface of the first flange 76 faces the upper surface of the second flange 78.

[0021] Multiple blades 77 rise upward from the upper surface of the first flange 76. The multiple blades 77 are arranged circumferentially. In this example, all blades 77 have the same shape and dimensions. Each blade 77 extends in a curved manner from the inner circumferential end of the first flange 76 to the outer circumferential end of the first flange 76. In this example, when viewed from above, each blade 77 extends obliquely in a clockwise direction with respect to the radial direction from the inner circumferential end to the outer circumferential end. The height of each blade 77 from the upper surface of the first flange 76 decreases, for example, from the inner circumferential end to the outer circumferential end of the blade 77. In other words, the height of each blade 77 may differ between the inner and outer circumferential ends, and more preferably, the height of the inner circumferential end of each blade 77 may be greater than the height of the outer circumferential end.

[0022] The magnet 74 is fixed to the cylinder 75 below the second flange 78. In this example, the magnet 74 is formed in a cylindrical shape with axis x as its center. The magnet 74 is divided into two cylindrical parts in the axial direction, for example, but is not limited to this, and may be composed of a single magnet. The upper surface of the magnet 74 is in contact with the lower surface of the second flange 78. The lower surface of the magnet 74 coincides with the lower end of the cylinder 75. This magnet 74 is, for example, a permanent magnet. The magnet 74 has, for example, alternating regions magnetized as south poles and regions magnetized as north poles in the circumferential direction. In this case, the division position or magnetic center of the magnet 74 coincides with the magnetic center position of the stator 8 in the axial direction, but is not limited to this, and may be shifted upward in the axial direction. In this case, the magnetic force acts to pull the magnet 74 towards the stator 8, that is, downward in the axial direction, so that the rotating body 7 does not float upward in the axial direction.

[0023] In the axial direction, a predetermined gap is secured between the upper end of the bearing 71 and the lower surface of the support portion 34, and between the lower ends of the bearing 71 and rotor 72 and the base 6. The first flange 76 and blades 77 of the rotor 72 are housed in the first space S1, while the magnet 74 is housed in the second space S2. In the axial and radial directions, the blades 77 face the inner surface of the main body 31 of the case 3 with a predetermined gap between them. In the radial direction, the outer circumferential surface of the magnet 74 faces the inner circumferential surface of the inner wall 42 with a predetermined gap between them. Also, in the axial direction, the lower surface of the magnet 74 faces the bottom wall 41 of the can portion 4 and the base 6 with a predetermined gap between them.

[0024] Figure 4 is a cross-sectional view along line 4-4 in Figure 3. Referring to both Figures 3 and 4, the pump device 1 includes a stator 8 incorporated into the can section 4. Specifically, the stator 8 is positioned in an annular space between the inner wall 42 and the outer wall 44 and fixed to the inner circumferential surface of the outer wall 44. The stator 8 includes a stator core 81, a plurality of coils 82, and an insulator 83. The stator core 81 is formed from a laminate of a plurality of thin plates stacked in the axial direction. The laminate is made of a magnetic material. The coils 82 have windings, for example, made of copper wire. The insulator 83 electrically insulates the stator core 81 from the plurality of coils 82. The insulator 83 is made of an insulating material, for example, a resin material.

[0025] The stator core 81 comprises an annular portion 84 and a plurality of teeth 85. The annular portion 84 is fixed to the inner circumferential surface of the outer wall 44 of the can portion 4. The annular portion 84 is defined in an annular shape around the axis x. Each tooth 85 protrudes inward from the inner circumferential surface of the annular portion 84. Each tooth 85 faces the outer circumferential surface of the magnet 74 of the rotor 72 with a predetermined magnetic gap, with the inner wall 42 of the can portion 4 in between. The windings of the coil 82 are wound around the insulator 83 that covers each tooth 85. In this example, there are six teeth 85, but the number of teeth 85 can be any number, such as 12 or 18. The number of poles of the rotor 72 can also be changed in accordance with the change in the number of teeth 85.

[0026] In the pump device 1, when current is supplied to the coil 82, the magnetic interaction between the coil 82 and the magnet 74 causes the rotor 72 to rotate counterclockwise around the axis x. This rotation generates a flow of coolant from the inlet 32 ​​into the first space S1 via multiple blades 77. The coolant flows outwards through the multiple blades 77 and then flows out from the outlet 33. In this way, the coolant is pumped to, for example, a drive source. The coolant may include, for example, water. Other liquids may be included in the water. Other liquids may include, for example, antifreeze such as propylene glycol or ethylene glycol, or rust inhibitors.

[0027] Figures 5 and 6 are schematic perspective views showing the structure of a base 6 according to one specific example. Figure 7 is a cross-sectional view of the base 6 along line 7-7 in Figure 6. Figure 5 is a perspective view of the base 6 seen from above in the axial direction, and Figure 6 is a perspective view of the base 6 seen from below in the axial direction. Referring to Figures 5 to 7 together, the base body 61 of the base 6 is formed in a disc shape centered on axis x. As mentioned above, a through hole 62 is formed in the base body 61 along axis x. That is, the base body 61 is formed in an annular shape. The through hole 62 penetrates from the upper surface 61a to the lower surface 61b of the base body 61 along axis x.

[0028] An annular groove 63 is formed on the lower surface 61b of the base body 61, extending circumferentially around the axis x. The groove 63 is recessed upward from the lower surface 61b toward the upper surface 61a. An elastic resin member, such as an O-ring, i.e., a gasket 64, is fitted into the groove 63. In this example, the upper surface 61a of the base body 61 is defined along a plane perpendicular to the axis x. The groove 63 divides the base body 61 into an annular portion on the inner circumference side of the groove 63 (hereinafter referred to as the "inner circumference portion") 61c and an annular portion on the outer circumference side of the groove 63 (hereinafter referred to as the "outer circumference portion") 61d.

[0029] The lower surface 61b of the base body 61 has a lower surface 61b of the inner circumference 61c and a lower surface 61b of the outer circumference 61d. Both lower surfaces 61b are defined along a plane perpendicular to the axis x. As shown particularly in Figure 7, the inner circumference 61c protrudes downward in the axial direction compared to the outer circumference 61d. That is, the distance from the upper surface 61a to the lower surface 61b is set to be greater for the inner circumference 61c than for the outer circumference 61d. The base body 61 is formed from a metal material with high thermal conductivity, such as aluminum. The thermal conductivity of the metal material of the base body 61 is greater than that of the resin material forming the can portion 4.

[0030] One or more notches 65 are formed in the outer circumferential surface 61e of the base body 61 (outer circumferential portion 61d). The notches 65 are recesses that extend inward from the outer circumferential surface 61e of the base body 61. In this example, the notches 65 are exposed on the upper surface 61a and the lower surface 61b of the base body 61. That is, the notches 65 extend from the upper surface 61a to the lower surface 61b of the base body 61. On the other hand, in this example, the notches 65 are interrupted on the outer circumferential side of the groove 63. That is, the notches 65 do not reach the groove 63. The notches 65 may have any shape, but in this example they generally have a rectangular parallelepiped shape.

[0031] Figure 8 is a partially enlarged perspective cross-sectional view schematically showing a part of the structure of the pump device 1. The cross-section in Figure 8 corresponds to the cross-section in Figure 3. Figure 9 is a partially enlarged cross-sectional view along the line 9-9 in Figure 3. Referring to Figures 8 and 9 together, as described above, a through hole 41a is formed in the bottom wall 41 of the can portion 4 of the housing 2, penetrating the bottom wall 41 in the axial direction. The through hole 41a has a small diameter portion 41b and a large diameter portion 41c. The diameter of the large diameter portion 41c is defined to be larger than the diameter of the small diameter portion 41b. The large diameter portion 41c opens upward in the axial direction. The small diameter portion 41b opens downward in the axial direction. An annular bottom surface 41d is formed in the large diameter portion 41c.

[0032] The diameter of the small-diameter portion 41b matches the diameter of the outer surface of the inner circumference portion 61c of the base body 61. The diameter of the large-diameter portion 41c matches the diameter of the outer surface 61e of the base body 61. The base 6 is fixed within this through hole 41a. Specifically, the inner circumference portion 61c of the base body 61 is positioned in the small-diameter portion 41b of the through hole 41a. The outer surface portion 61d of the base body 61 is positioned in the large-diameter portion 41c of the through hole 41a. The gasket 64 fitted into the groove 63 of the base body 61 is compressed between the bottom surface of the groove 63 and the bottom surface 41d of the large-diameter portion 41c of the through hole 41a. As a result, the space between the base 6 and the bottom wall 41 of the can portion 4 is sealed, preventing fluid from leaking from the can portion 4 towards the circuit board 9. The lower surface 61b of the inner circumference portion 61c of the base body 61 is positioned below the lower surface of the bottom wall 41.

[0033] The base 6 is integrated with the can portion 4 by insert molding. Specifically, when the can portion 4 is molded from resin material, the base 6, with a gasket 64 fitted into a groove 63 and a shaft 48 press-fitted into a through hole 62, is pre-positioned in the mold. When resin material is injected into the mold in this state, the base 6 is fixed within the through hole 41a of the bottom wall 41 of the can portion 4. Therefore, as shown in Figure 9, the resin material flows into the notch 65 on the outer peripheral surface 61e of the base body 61. In this way, a part of the bottom wall 41 is positioned within the notch 65. This positioning of a part of the bottom wall 41 within the notch 65 prevents the base 6 from rotating around the axis x.

[0034] Referring together to Figures 3 and 8, the pump device 1 includes a circuit board 9 incorporated within the can section 4. In this example, the circuit board 9 is formed in a circular shape along a plane perpendicular to the axis x. One or more electronic components 91 are provided on the front and back surfaces of the circuit board 9. These electronic components 91 include, for example, field-effect transistors (FETs) and capacitors. Wiring, i.e., connector pins 92, are also mounted on the circuit board 9. In this example, the upper surface 51b of the main body 51 of the cover 5 faces the back surface of the circuit board 9. The connector pins 92 protrude downward from the back surface of the circuit board 9 and extend into the connector housing 53.

[0035] Some of the coils 82 are electrically connected to the circuit board 9 by terminals 93. Meanwhile, connector pins 92 mounted on the circuit board 9 are connected to connectors (not shown) of external devices. Power and signals are supplied from the external device to the electronic components 91 and coils 82 on the circuit board 9 via these connector pins 92 and terminals 93. For example, the supply of power causes the electronic components 91 and coils 82 on the circuit board 9 to generate heat. In one example, the temperature due to the heat generated by the electronic components 91 tends to be higher than the temperature due to the heat generated by the coils 82.

[0036] The base 6 and the electronic components 91 on the circuit board 9 are in contact with each other via another material (hereinafter referred to as "thermal conductive material") 94 having high thermal conductivity. Specifically, the thermal conductive material 94 is sandwiched between the lower surface 61b of the inner circumference 61c of the base body 61 of the base 6 and the upper surface of the electronic components 91 on the circuit board 9. The thermal conductive material 94 is formed, for example, in the shape of a flat disc centered on axis x. The thermal conductive material 94 extends radially larger than the lower surface 61b of the inner circumference 61c of the base body 61. That is, the thermal conductive material 94 is in contact with the entire surface of the lower surface 61b.

[0037] In this example, all electronic components 91 mounted on the surface of the circuit board 9 are in contact with the heat conductive member 94. Even if the height of each electronic component 91 from the surface of the circuit board 9 differs, this height can be absorbed, for example, by adjusting the thickness of the heat conductive member 94. In this way, all electronic components 91 on the surface of the circuit board 9 can be in contact with the heat conductive member 94. In this example, the heat conductive member 94 is a heat conductive sheet, but as an alternative, it may be a paste-like fluid having a predetermined viscosity, such as thermally conductive silicone.

[0038] Figure 10 is a partially enlarged cross-sectional view illustrating the heat conduction path. In the pump device 1, heat is generated in the electronic component 91 due to the supply of power from an external device to the circuit board 9 and coil 82. This heat is conducted via the heat conduction member 94 to the base body 61 of the base 6, which is made of a metal material with high thermal conductivity. In this way, the heat conduction member 94 and the base 6 form a heat conduction path P. In the base body 61, heat is transferred to the coolant from the upper surface 61a of the base body 61, which is the part that comes into contact with the coolant in the internal space S, i.e., the second space S2. Since the coolant circulates within the internal space S, the heat is released from the pump device 1 together with the coolant. As a result, the electronic component 91 can be cooled efficiently.

[0039] Furthermore, since the base 6 is formed from a metal material while the can portion 4 is formed from a resin material, the base 6 and the can portion 4 have different coefficients of linear expansion. In this case, when heat generated from the electronic components 91 and coil 82 is transferred to the base 6 and the can portion 4, the temperature change will cause a difference in dimensional change between the base 6 and the can portion 4. However, in the pump device 1, a gasket 64 is interposed between the base 6 and the bottom wall 41 of the can portion 4 to seal the space, so even if there is a difference in the coefficients of linear expansion, leakage of coolant from the internal space S to the outside through the space between the base 6 and the can portion 4 can be prevented.

[0040] In the pump device 1 described above, the groove 63 formed in the base body 61 of the base 6 may be formed, for example, on the outer circumferential surface 61e of the base body 61. In this case, for example, a projection for preventing the base 6 from rotating may be provided on the lower surface 61b of the base body 61. This projection engages with a recess in the bottom wall 41. In addition, one or more grooves may be formed on the upper surface 61a and lower surface 61b of the base body 61 to increase the contact area with the coolant and the heat conduction member 94. Furthermore, the heat conduction member 94 may be designed to contact all of the electronic components 91 on the circuit board 9, or it may be designed to contact some of the electronic components 91. Furthermore, the electronic components 91 may contact the lower surface 61b of the base body 61 directly without going through the heat conduction member 94.

[0041] Figure 11 is a partially enlarged cross-sectional view schematically showing the structure of a pump device 1A according to another embodiment of the present invention. The cross-section shown in Figure 11 is a cross-section along a plane containing axis x. A base 10 is attached to the bottom wall 41 of the can portion 4 of this pump device 1A in place of the base 6 described above. Specifically, the base 10 is positioned in a through hole 41a formed in the bottom wall 41. The base 10 is integrally formed in the bottom wall 41 of the can portion 4, for example, by insert molding. Between the base 10 and the circuit board 9 described above, the cap 11 and the heat conductive member 94 described above are positioned in the axial direction. Also, the gasket 64 described above is sandwiched between the base 10 and the cap 11. Other components similar to those of the pump device 1 described above are given the same reference numerals, and redundant explanations are omitted here.

[0042] Figure 12 is a cross-sectional view along line 12-12 in Figure 11. Figures 13 and 14 are exploded perspective views schematically showing the structure of the base 10, gasket 64, cap 11, and heat conductive member 94. Referring together to Figures 11 to 14, the base 10 has a cylindrical body 101 centered on axis x, a first projection 102 projecting upward in the axial direction from the upper surface of the body 101, and a second projection 103 projecting downward in the axial direction from the lower surface of the body 101. In this example, both the first projection 102 and the second projection 103 are formed in a cylindrical shape centered on axis x. The radial dimension (diameter) of the first projection 102 is larger than the radial dimension (diameter) of the second projection 103. The base 10 is formed from a metal material with high thermal conductivity, such as aluminum.

[0043] The base 10 is formed with a through-hole 104 that axially penetrates the main body 101, the first protrusion 102, and the second protrusion 103. The aforementioned shaft 48 is supported in this through-hole 104, for example, by being press-fitted. Further, around the through-hole 104 of the main body 101, one or more hole portions 105 are formed at predetermined intervals in the circumferential direction. The hole portions 105 axially penetrate the main body 101. In this example, three hole portions 105 are formed at equal intervals in the circumferential direction. The main body 101 is embedded in the bottom wall 41. In insert molding, the hole portions 105 are filled with the resin material that forms the bottom wall 41. As a result, a part of the bottom wall 41 enters the hole portions 105, thereby forming a rotation prevention that prevents the base 10 from rotating around the axis x with respect to the bottom wall 41 of the can portion 4.

[0044] As described above, the base 10 is attached in the through-hole 41a of the bottom wall 41 of the can portion 4. The first protrusion 102 of the base 10 is exposed on the upper surface side of the bottom wall 41. That is, the annular upper surface of the first protrusion 102 faces the lower end of the bearing 71 in the axial direction. On the other hand, the second protrusion 103 of the base 10 is exposed on the lower surface 41d side of the bottom wall 41. Thus, in this example, the main body 101 of the base 10 is embedded in the bottom wall 41. That is, the main body 101 is not exposed on the upper surface and the lower surface 41d of the bottom wall 41. In this example, the annular lower surface 103a of the second protrusion 103 is defined flush with the annular lower surface 41d of the bottom wall 41. That is, the annular lower surface 103a of the second protrusion 103 and the annular lower surface 41d of the bottom wall 41 are defined along a plane orthogonal to the axis x.

[0045] In this example, the cap 11 has a first step portion 111, a second step portion 112, and a third step portion 113 that are stacked in the axial direction. The first step portion 111, the second step portion 112, and the third step portion 113 are all formed in a cylindrical shape centered on axis x. The second step portion 112 is formed on the upper surface of the first step portion 111, and the third step portion 113 is formed on the upper surface of the second step portion 112. In this example, the radial dimension (diameter) decreases as you move from the first step portion 111 through the second step portion 112 to the third step portion 113. Thus, annular stepped surfaces are defined for the first step portion 111 and the second step portion 112, respectively. In one example, these stepped surfaces and the upper surface 113a of the third step portion 113 are defined along a plane perpendicular to axis x.

[0046] The cap 11 has a recess 114 formed on the lower surface of the first step portion 111, and a through hole 115 formed within the recess 114 that penetrates the cap 11 axially. The through hole 115 is continuous with the recess 114 in the axial direction. In one example, the recess 114 and the through hole 115 define a cylindrical space centered on axis x. The radial dimension (diameter) of the recess 114 is larger than the radial dimension (diameter) of the through hole 115. The cap 11 is fixed to the can portion 4 by a fixing member, i.e., a bolt 12. Specifically, the cap 11 is attached to the shaft 48 by screwing the bolt 12 into the lower end of the shaft 48 through the through hole 115. In this example, the head of the bolt 12 is completely housed within the recess 114. An annular washer 13 is placed between the head of the bolt 12 and the bottom surface of the recess 114.

[0047] As shown in FIG. 11, the upper surface 113a of the third step portion 113 of the cap 11 receives and contacts the lower surface 103a of the second protrusion 103 of the base 6. Also, the annular upper surface 112a of the second step portion 112 of the cap 11 and the lower surface 41d of the bottom wall 41 face each other in the axial direction, so that a predetermined gap G is formed between the upper surface 112a of the second step portion 112 and the lower surface 41d of the bottom wall 41. The aforementioned gasket 64 is disposed between the base 6 and the cap 11. Specifically, the gasket 64 is sandwiched between the annular lower surface of the main body 101 of the base 6 and the annular upper surface 112a of the second step portion 112 of the cap 11 in the axial direction, and is sandwiched between the outer peripheral surface of the second protrusion 103 of the base 6 and the inner peripheral surface of the through-hole 41a of the bottom wall 41 in the radial direction. Thus, the gasket 64 seals between the base 6, the bottom wall 41, and the cap 11.

[0048] The lower surface of the first step portion 111 of the cap 11 is received and contacts the upper surface of the heat conductive member 94. In this example, the heat conductive member 94 is formed in a circular shape in plan view. The radial dimension (diameter) of the heat conductive member 94 is larger than the radial dimension (diameter) of the first step portion 111 of the cap 11. The lower surface of the heat conductive member 94 contacts the electronic component 91 mounted on the surface of the circuit board 9. The cap 11 is formed of a metal material having high thermal conductivity such as aluminum, for example. That is, the cap 11 is another member having thermal conductivity. Also, the bolt 12 is formed of a metal material, for example, and the washer 13 is formed of an elastic material such as rubber or a metal material such as copper. According to such a configuration, the heat generated by the electronic component 91 is efficiently transmitted to the cooling liquid via the heat conductive member 94, the cap 11, the base 10, the bottom wall 41, and the like.

[0049] In the manufacturing process of this pump device 1A, resin material is injected into a mold incorporating the base 10 when the can portion 4 is being molded. By performing insert molding in this way, the base 10 is integrally formed with the can portion 4. Subsequently, with a gasket 64 positioned between the inner circumferential surface of the through hole 41a of the bottom wall 41 and the outer circumferential surface of the second projection 103 of the base 10, the cap 11 is attached to the can portion 4 by screwing a bolt 12 onto a shaft 48 that has been press-fitted into the through hole 104 of the base 10. This screwing causes the upper surface 113a of the third stage portion 113 of the cap 11 to contact the lower surface 103a of the second projection 103 of the base 10. At the same time, a gap G is secured between the upper surface 112a of the second stage portion 112 of the cap 11 and the lower surface 41d of the bottom wall 41. As the cap 11 is attached to the can portion 4 in this way, the gasket 64 is sandwiched between the cap 11 and the bottom wall 41 and the base 10.

[0050] Figure 15 is a partially enlarged cross-sectional view schematically showing the structure of a pump device 1B according to yet another embodiment of the present invention. The cross-section shown in Figure 15 is a cross-section along a plane containing axis x. In this pump device 1B, a base 10A and a cap 11A are incorporated in place of the base 10 and cap 11 described above. The base 10A is integrally formed, for example by insert molding, in the through hole 41a of the bottom wall 41 of the can portion 4, similar to the base 10 described above. The cap 11A and the heat conductive member 94 are arranged between the base 10A and the circuit board 9. Gaskets 66 and 67 are sandwiched between the cap 11A and the bottom plate 41 and shaft 48. Other components similar to those of the pump devices 1 and 1A described above are given the same reference numerals, and redundant explanations are omitted here.

[0051] Figure 16 is a cross-sectional view along line 16-16 in Figure 15. Figure 17 is an exploded perspective view schematically showing the structure of the base 10A, gaskets 66, 67, cap 11A, and heat conduction member 94. Referring together to Figures 15 to 17, the base 10A, in one example, has a body 106 and a projection 107 that protrudes upward in the axial direction from the body 106. The body 106 and the projection 107 are each formed in a disc shape, for example, centered on axis x. The radial dimension (diameter) of the body 106 is larger than the radial dimension (diameter) of the projection 107. In this example, the outer circumferential surface of the projection 107 is defined as a frustoconical surface whose diameter decreases from the bottom to the top in the axial direction. The base 10A is integrally formed from a metal material with high thermal conductivity, such as aluminum.

[0052] The base 10A has a through hole 108 that penetrates the main body 106 and the projection 107 in the axial direction. The shaft 48 is supported by, for example, press-fitting into this through hole 108. In this example, the shaft 48 has a portion 48a with a relatively large radial dimension (diameter) (hereinafter referred to as the "large diameter portion") and a portion 48b with a smaller radial dimension (diameter) than the large diameter portion 48a (hereinafter referred to as the "small diameter portion") (see Figure 15). The small diameter portion 48b is integrally formed continuously from the lower end of the large diameter portion 48a. In this example, the small diameter portion 48b of the shaft 48 is supported by press-fitting into the through hole 108 of the base 10A. In addition, the annular upper surface 107a of the projection 107 of the base 10A is in contact with the stepped surface 48c between the large diameter portion 48a and the small diameter portion 48b.

[0053] Furthermore, in the base 10A, one or more holes 109 are formed around the through hole 108 of the main body 106 at predetermined intervals in the circumferential direction. The holes 109 penetrate the main body 106 in the axial direction. In this example, six holes 109 are formed at equal intervals in the circumferential direction. The main body 106 is embedded in the bottom wall 41. During insert molding, the resin material that forms the bottom wall 41 is filled into these holes 109. In this way, a part of the bottom wall 41 enters the holes 109, forming an anti-rotation mechanism that prevents the base 10A from rotating around the axis x relative to the bottom wall 41. Note that the number of holes 109 may be other than six. Also, in this example, each hole 109 is arranged offset from the inner circumference to the outer circumference in the radial direction.

[0054] In one example, the cap 11A has a body 116 and a projection 117 that protrudes upward in the axial direction from the body 116. The body 116 is formed in the shape of a disc with axis x as its center. The projection 117 is formed in the shape of a cylinder with axis x as its center. Thus, an annular upper surface 116a is defined on the body 116 on the outer circumference side of the projection 117. The body 116 also has a lower surface 116b that faces away from the upper surface 116a. The projection 117 also has, for example, a cylindrical outer surface 117a with axis x as its central axis, and a cylindrical inner surface 117b with axis x as its central axis. The cylindrical outer surface 117a faces the outer circumference. The cylindrical inner surface 117b faces the inner circumference. The projection 117 also has an annular upper surface 117c. In one example, the upper surface 116a, the lower surface 116b, and the upper surface 117c are defined along a plane perpendicular to the axis x.

[0055] On the inner circumference side of the protrusion 117, the main body 116 has a through hole 118 that penetrates the main body 116 along the axis x. The cap 11A is fixed to the can portion 4 by the bolt 12 mentioned above. Specifically, the cap 11A is attached to the shaft 48 by screwing the bolt 12 into the lower end of the small diameter portion 48b of the shaft 48 through the through hole 118. In this example, the head of the bolt 12 is in contact with the lower surface 116b of the main body 116 of the cap 11A. When the cap 11A is attached to the shaft 48, the lower surface 106a of the main body 106 of the base 10A comes into contact with the upper surface 117c of the protrusion 117. In this example, the upper surface 117c and the lower surface 106a are defined along a plane perpendicular to the axis x. On the other hand, in this example, a gap G is formed in the axial direction between the annular upper surface 116a of the main body 116 of the cap 11A and the lower surface 41d of the bottom wall 41.

[0056] As shown in Figure 15, when the cap 11A is attached to the shaft 48, the protrusion 117 of the cap 11A enters the through hole 41a of the bottom wall 41. In this example, gaskets 66 and 67 are placed between the cap 11A and the shaft 48 and bottom wall 41. The gaskets 66 and 67 are formed from an elastic annular resin member, such as an O-ring, similar to the gasket 64 described above. Gasket 66 is positioned on the inner circumference side of gasket 67. In this example, in the radial direction, gasket 66 is elastically deformed by being sandwiched between the outer circumferential surface of the small diameter portion 48b of the shaft 48 and the inner circumferential surface 117b of the protrusion 117. In the radial direction, gasket 67 is elastically deformed by being sandwiched between the inner circumferential surface of the through hole 41a of the bottom wall 41 and the outer circumferential surface 117a of the protrusion 117. In this way, the gaskets 66 and 67 seal the space between the cap 11A and the shaft 48 and the bottom wall 41 in the axial direction.

[0057] In this example, the aforementioned heat conductive member 94 is positioned between the cap 11A and the circuit board 9. In this example, the heat conductive member 94 has a hole 94a that extends axially along the axis x. The head of the bolt 12 is positioned within the hole 94a of the heat conductive member 94. In this example, the hole 94a penetrates the heat conductive member 94 axially, but the hole 94a may be a recess with a bottom. As mentioned above, the heat conductive member 94 is formed, for example, from a heat conductive sheet. In addition, a thermally conductive grease or the like may be sandwiched between the upper surface 117c of the convex portion 117 of the cap 11A and the lower surface 106a of the main body 106 of the base 10A. The interposition of such thermally conductive grease can increase the efficiency of heat conduction between the cap 11A and the base 10A.

[0058] In the pump device 1B described above, the gaskets 66 and 67 are sandwiched radially between the inner circumferential surface 117b of the protrusion 117 of the cap 11A and the outer circumferential surface of the small diameter portion 48b of the shaft 48, and between the outer circumferential surface 117a of the protrusion 117 and the inner circumferential surface of the through hole 41a of the bottom wall 41, and are elastically deformed at least radially. This elastic deformation of the gaskets 66 and 67 seals the space between the protrusion 117 of the cap 11A and the shaft 48, and the space between the protrusion 117 and the bottom wall 41. In other words, the gaskets 66 and 67 seal the space between the cap 11A and the shaft 48 and the bottom wall 41 in the axial direction. As a result, for example, leakage of coolant from between the shaft 48 and the base 10A toward the circuit board 9 in the axial direction can be suppressed. Furthermore, it is preferable that the outer circumferential surface 117a and inner circumferential surface 117b of the protrusion 117, the outer circumferential surface of the small diameter portion 48b, and the inner circumferential surface of the through hole 41a have high smoothness in order to improve adhesion with the gaskets 66 and 67.

[0059] In particular, when the pump device 1B is operating, pressure acts on the bottom wall 41 from the second space S2 of the can section 4 in the axial direction downward. The gaskets 66 and 67 each seal the space between the cap 11A and the shaft 48 and the bottom wall 41 in the axial direction, so regardless of the pressure acting on them, leakage of coolant in the axial direction can be suppressed. Furthermore, even if a small gap is created between the lower surface 106a of the main body 106 of the base 10A and the upper surface 117c of the protrusion 117 of the cap 11A due to the downward pressure acting on the bottom wall 41, leakage of coolant in the axial direction can be suppressed by the axial sealing by the gaskets 66 and 67. In addition, since conductive grease is sandwiched between the lower surface 106a and the upper surface 117c, even if a gap is created between them, the heat conduction path from the cap 11A to the base 10A is ensured.

[0060] In this pump device 1B, as described above, a gap G is formed in the axial direction between the annular upper surface 116a of the body 116 of the cap 11A and the lower surface 41d of the bottom wall 41, but this gap G does not have to be formed. That is, the upper surface 116a of the body 116 of the cap 11A may be in contact with the lower surface 41d of the bottom wall 41. With this configuration, the cross-sectional area of ​​the heat conduction path from the circuit board 9 to the bottom wall 41 via the heat conduction member 94 and the cap 11A can be increased, so that the heat generated by the electronic components 91 of the circuit board 9 is efficiently transferred to the coolant via the heat conduction member 94, the cap 11A and the bottom wall 41, etc. The gaskets 66 and 67 may also be sandwiched in the axial direction between the body 106 of the base 10A and the body 116 of the cap 11A and elastically deformed in the axial direction. In this way, the gaskets 66 and 67 seal the space between the cover 10A and the cap 11A in the radial direction.

[0061] Although the present invention has been described above through the embodiments described above, the technical scope of the present invention is not limited to the scope described in the embodiments above. It will be obvious to those skilled in the art that various modifications or improvements can be made to the embodiments described above. It will be clear from the claims that such modified or improved forms may also be included in the technical scope of the present invention.

[0062] The embodiments described above are for the purpose of facilitating understanding of the present invention and are not intended to limit its interpretation. Furthermore, the embodiments described above do not limit the scope of application of the present invention, and the present invention may encompass anything as its target application. The components of the above embodiments, as well as their arrangement, materials, conditions, shapes, sizes, etc., are not limited to those exemplified and can be modified as appropriate.

[0063] For example, the present invention includes differences that arise in the implementation of manufacturing tolerances, etc. Furthermore, components shown in different embodiments can be partially substituted or combined to the extent that they do not conflict with the technical requirements. In addition, each component can be selectively combined as appropriate to achieve at least some of the above-mentioned problems and effects.

[0064] 1, 1A, 1B Pump device, 2 Housing, 3 Case, 31 Main body, 32 Inlet, 33 Outlet, 34 Support part, 34a Recess, 35 Spoke, 4 Can part, 41 Bottom wall, 41a Through hole, 41b Small diameter part, 41c Large diameter part, 41d Bottom surface, 42 Inner wall, 43 Top wall, 44 Outer wall, 45 Flange, 46 Groove part, 47 Gasket, 48 Shaft, 48a Large diameter part, 48b Small diameter part, 5 Cover, 51 Main body, 51a Bottom surface, 51b Top surface, 52 Fin, 53 Connector housing, 54 Fixing member, 6 Base, 61 Base body, 61a Top surface, 61b Bottom surface, 61c Circumferential annular part on the inner circumference (Inner circumference), 61d Circumferential annular part on the outer circumference (Outer circumference), 61e Outer circumference surface, 62 63 Through hole, 64 Groove, 64 Gasket (elastic resin member), 65 Notch, 66, 67 Gasket, 7 Rotating body, 71 Bearing, 72 Rotor, 73 Impeller body, 74 Magnet, 75 Cylinder, 76 First flange, 77 Blades, 78 Second flange, 8 Stator, 81 Stator core, 82 Coil, 83 Insulator, 84 Annular part, 85 Teeth, 9 Circuit board (board), 91 Electronic component, 92 Connector pin (wiring), 93 Terminal, 94 Other thermally conductive member (thermal conductive member), 94a Hole, 10, 10A Base, 101 Body, 102 First projection, 103 Second projection, 103a Bottom surface, 104 Through hole, 105 Hole, 106 Body, 106a Bottom surface, 107 Projection, 107a Top surface, 108 Through hole, 109 Hole, 11, 11A Cap, 111 First step, 112 Second step, 113 Third step, 113a Top surface, 114 Recess, 115 Through hole, 116 Main body, 116a Top surface, 116b Bottom surface, 117 Convex portion, 117a outer peripheral surface, 117b inner peripheral surface, 117c upper surface, 12 bolt (fastening member), 13 washer, S internal space, S1 first space, S2 second space, x axis

Claims

1. A pump device comprising: a shaft; a rotor rotatably supported on the shaft; a housing for the rotor; a stator fixed to the housing; a base supporting the shaft; and an electronic component that generates heat, wherein the base has greater thermal conductivity than the housing, and the electronic component is in contact with the base.

2. The pump device according to claim 1, wherein the electronic component is provided on a substrate having wiring, and the base and the electronic component are in contact with each other via another thermally conductive member.

3. The pump device according to claim 1 or 2, wherein an elastic resin member is interposed between the base and the housing.

4. The pump device according to any one of claims 1 to 3, wherein the base has a portion that comes into contact with the fluid in the housing, and the heat generated from the electronic components is transferred to the fluid via the base.

5. The pump device according to claim 2, wherein power is supplied from an external device via the aforementioned wiring.

6. The pump device according to claim 1 or 2, comprising a cap attached to the base, wherein an elastic resin member is interposed between the cap and the housing.

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