Rotating body and pump device

Abstract

A rotating body (5) comprises: a first resin member (6) that is supported so as to be rotatable with respect to a shaft (45); and a second resin member (7) that is fixed to the first resin member (6) and is formed from a thermoplastic resin. The first resin member (6) has an outer peripheral surface (64a) having a section (64a) that restricts relative rotation of the first resin member (6) with respect to the second resin member (7). The first resin member (6) has higher slidability than the second resin member (7).

Description

Rotating body and pump device

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

[0002] For example, Patent Document 1 discloses a rotor for an electric water pump for pumping a coolant inside an engine of a vehicle or the like. This rotor has a main body portion that supports an impeller, a sliding bearing that rotatably supports a shaft, and a magnet fixed to the main body portion.

[0003] Japanese Patent Application Laid-Open No. 2017-25742

[0004] The rotor is rotatably supported on the shaft via a sliding bearing. In order to rotate the rotor efficiently and with high reliability, high slidability is required for the sliding bearing.

[0005] The present invention has been made in view of the above problems, and one of the problems is to provide a rotating body and a pump device having high slidability.

[0006] A rotating body according to one aspect of the present invention includes a first resin member rotatably supported with respect to a shaft, and a second resin member formed of a thermoplastic resin fixed to the first resin member. An outer peripheral surface of the first resin member includes a portion that restricts relative rotation of the first resin member with respect to the second resin member, and the first resin member has higher slidability than the second resin member.

[0007] A pump device according to one aspect of the present invention includes the rotating body described above and a casing through which a fluid flows. The first resin member and the second resin member are housed in the casing. The first resin member includes a first surface facing in the axial direction and a second surface facing the shaft in the radial direction. The first surface has a first dynamic pressure groove, and the second surface has a groove extending in the axial direction, and the fluid flows through the groove.

[0008] 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 2-2 in Figure 1. This is a schematic perspective view showing the configuration of a rotating body 5 according to one embodiment of the present invention. This is a cross-sectional view along line 4-4 in Figure 3. This is a schematic perspective view showing the structure of a bearing 6 according to one specific example. This is a schematic perspective view showing the structure of a bearing 6 according to one specific example. This is a cross-sectional view along line 7-7 in Figure 5. This is a cross-sectional view along line 8-8 in Figure 3. This is a perspective cross-sectional view of a cross section along line 9-9 in Figure 7. This is a cross-sectional view along line 10-10 in Figure 2.

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the attached drawings. Figure 1 is a schematic perspective view 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.

[0010] 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.

[0011] Figure 2 is a cross-sectional view along line 2-2 in Figure 1. Referring to both Figures 1 and 2, the pump device 1 includes a casing 2 formed in a generally cylindrical shape with axis x as the center. The casing 2 has a case 3 and a can section 4 arranged along axis x. The case 3 and the can section 4 are formed by injection molding from a thermoplastic resin material, such as PPS (polyphenylene sulfide). The case 3 and the can section 4 define the internal space of the casing 2. The lower opening of the can section 4 is covered with a cover (not shown).

[0012] 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 casing 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 casing 2.

[0013] The can section 4 is formed as a whole, for example, in a cylindrical shape. The case 3 is attached to the upper side of the can section 4. The can section 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 a cylindrical shape 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 an annular shape 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 a cylindrical shape centered on the axis x.

[0014] An internal space S is formed within the casing 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.

[0015] 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 cylindrical 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.

[0016] The pump device 1 includes a shaft 45 positioned in the internal space S of the casing 2. The shaft 45 is formed in a cylindrical shape, for example, with an axis x as its center. The upper end of the shaft 45 is partially housed and fixed in a recess 36 formed on the lower surface of the support portion 34 of the case 3. On the other hand, the lower end of the shaft 45 is fixed in a through hole 41a that penetrates the bottom wall 41 along the axis x. For fixing, the lower end of the shaft 45 is, for example, press-fitted into the through hole 41a. Adhesive may be applied between the shaft 45 and the through hole 41a. In this way, the inlet portion 32 and the shaft 45 are arranged adjacent to each other in the axial direction. The shaft 5 may be fixed in a bottomed hole formed in the bottom wall 41 instead of the through hole 41a. In this case, the shaft is in contact with the bottom surface of the bottomed hole in the axial direction.

[0017] The pump device 1 includes a rotating body 5 that is rotatably supported on a shaft 45 about an axis x. The rotating body 5 is housed in a casing 2. The rotating body 5 has a first resin member, i.e., a bearing 6, a second resin member, i.e., a rotating body body 7, and a magnet 8. The bearing 6 is formed in a cylindrical shape with an axis x as its center. The inner circumferential surface of the bearing 6 faces the outer circumferential surface of the shaft 45 with a predetermined gap between them. In this way, the bearing 6 is rotatably supported on the shaft 45 about an axis x, and is also supported to be movable relative to the shaft 45 in the vertical direction along the axis x. The bearing 6 is a so-called sliding bearing. The rotating body body 7 is fixed to the bearing 6 and rotates in accordance with the rotation of the bearing 6. The magnet 8 is fixed to the rotating body body 7.

[0018] Figure 3 is a schematic perspective view showing the configuration of a rotating body 5 according to one embodiment of the present invention. Figure 4 is a cross-sectional view along line 4-4 in Figure 3. Referring together to Figures 2 to 4, the rotating body 7 has a cylinder 71, a first flange 72, a plurality of blades 73, a second flange 74, and a side wall 75. These cylinder 71, first flange 72, plurality of blades 73, second flange 74, and side wall 75 are integrally formed by injection molding from a thermoplastic resin material, such as PPS (polyphenylene sulfide).

[0019] The cylinder 71 is formed in a cylindrical shape, for example, with axis x as its center. A first flange 72 extends radially in an annular shape from the upper end of the cylinder 71 in the axial direction. That is, the first flange 72 is formed in a disc shape with axis x as its center. On the other hand, a second flange 74 extends radially in an annular shape from the cylinder 71 between its upper and lower ends in the axial direction. In the axial direction, the lower surface of the first flange 72 faces the upper surface of the second flange 74. The side wall 75 extends downward in an annular shape from the lower surface of the second flange 74. The inner circumferential surface of the side wall 75 faces the outer circumferential surface of the cylinder 71 in the radial direction.

[0020] Multiple blades 73 rise upward from the upper surface of the first flange 72. The multiple blades 73 are arranged circumferentially. In this example, all blades 73 have the same shape and dimensions. Each blade 73 extends in a curved manner from the inner circumferential end of the first flange 72 to the outer circumferential end of the first flange 72. In this example, when viewed from above, each blade 73 extends diagonally in a counterclockwise direction with respect to the radial direction from the inner circumferential end to the outer circumferential end. The height of each blade 73 from the upper surface of the first flange 72 decreases, for example, from the inner circumferential end to the outer circumferential end of the blade 73. In other words, the height of each blade 73 may differ between the inner and outer circumferential ends, and more preferably, the height of the inner circumferential end of each blade 73 may be greater than the height of the outer circumferential end.

[0021] The magnet 8 is fixed to the outer surface of the side wall 75 below the second flange 74. For fixing, an adhesive may be applied between the inner surface of the magnet 8 and the outer surface of the side wall 75. In this example, the magnet 8 is formed in a cylindrical shape centered on axis x. The upper surface of the magnet 8 is in contact with the lower surface of the second flange 74. In one example, the magnet 8 extends radially outward from the second flange 74. The magnet 8 is, for example, a permanent magnet. The magnet 8 has, for example, alternating regions magnetized as south poles and regions magnetized as north poles in the circumferential direction.

[0022] The rotating body 7 has a rotor 76 and an impeller 77 arranged in the axial direction. The rotor 76 is adjacent to the lower side of the impeller 77 in the axial direction. The rotor 76 includes the portion below the second flange 74 in the axial direction. Specifically, the rotor 76 includes a portion of the cylinder 71 below the second flange 74, the second flange 74, and the side wall 75. On the other hand, the impeller 77 includes the portion above the first flange 72 in the axial direction. Specifically, the impeller 77 includes a portion of the cylinder 71 above the first flange 72, a plurality of blades 73, and the first flange 72. The rotor 76 and the impeller 77 are connected by a portion of the cylinder 71.

[0023] The rotating body 7 is fixed to the bearing 6 by a cylinder 71. The bearing 6 is formed by injection molding from a thermoplastic resin material, including, for example, a super engineering plastic such as polyetheretherketone (PEEK). This resin material has higher sliding properties than the resin material that forms the rotating body 7. Here, high sliding properties are represented, for example, by a small coefficient of friction on its surface and high wear resistance on its surface. The bearing 6 is placed inside the cylinder 71. In this example, the rotating body 5 is formed by insert molding by placing the bearing 6, which has been formed in advance by injection molding, into the mold, and then injecting the resin material that forms the rotating body 7 into the mold. However, the bearing 6 may be press-fitted into the cylinder 71 of the rotating body 7.

[0024] The bearing 6 comprises a cylindrical body 61 centered on axis x. As shown in Figure 4, the body 61 of the bearing 6 extends from the rotor 76 of the rotating body 7 to the impeller 77. In this example, the upper end of the body 61 protrudes above the upper end of the cylinder 71, while the lower end of the body 61 protrudes below the lower end of the cylinder 71. The length L1 of the bearing 6, i.e., the body 61, in the axial direction is longer than the length L2 of the cylinder 71 in the axial direction. In other words, the length L1 of the bearing 6, i.e., the body 6, in the axial direction is longer than the length L3 of the rotor 76 in the axial direction.

[0025] Figures 5 and 6 are schematic perspective views showing the structure of a bearing 6 according to one specific example. Figure 5 is a perspective view of the bearing 6 seen from above in the axial direction, and Figure 6 is a perspective view of the bearing 6 seen from below in the axial direction. Referring together to Figures 4 to 6, the body 61 of the bearing 6 is composed of a first part 62 located on the impeller 77 side, a second part 63 located on the rotor 76 side, and a third part 64 located between the first part 62 and the second part 63. The first part 62, the second part 63, and the third part 64 are arranged in the axial direction. The first part 62, the second part 63, and the third part 64 are integrally formed.

[0026] Figure 7 is a cross-sectional view along line 7-7 in Figure 5. Referring further to Figure 7, the first portion 62 and the second portion 63 are formed in an annular shape. In this example, the outer circumferential surfaces 62a and 63a of the first portion 62 and the second portion 63 are defined by cylindrical surfaces centered on axis x. The outer circumferential surfaces 62a and 63a of the first portion 62 and the second portion 63 constitute an annular portion. In the axial direction, the length L4 of the first portion 62 is longer than the length L5 of the second portion 63. In this example, the length L4 of the first portion 62 is set to approximately twice the length L5 of the second portion 63. Also, the length L6 of the third portion 64 is longer than the length L4 of the first portion 62 and the length L5 of the second portion 63.

[0027] On the other hand, the third portion 64 is formed in a polygonal shape. In this example, the outer circumferential surface 64a of the third portion 64 has four flat surfaces 64b defined along a plane parallel to the axis x, and four curved surfaces 64c defined along a cylindrical surface centered on the axis x. The four flat surfaces 64b and the four curved surfaces 64c are arranged alternately in the circumferential direction. In this way, eight angles 64d are formed on the outer circumferential surface 64a at the boundaries between the flat surfaces 64b and the curved surfaces 64c, extending parallel to the axis x. Thus, the outer circumferential surface 64a of the third portion 64 constitutes a portion having multiple angles 64d.

[0028] Figure 8 is a cross-sectional view along the line 8-8 in Figure 3. As shown in Figure 8, the outer circumferential surface 64a of the third portion 64 of the main body 61 of the bearing 6 is formed in an approximately octagonal shape in a cross section perpendicular to the axis x. The inner circumferential surface 71a of the cylinder 71 has a shape corresponding to the outer circumferential surface 64a of the third portion 64. With this configuration, the outer circumferential surface 64a of the third portion 64 has four flat surfaces 64b and angles 64d between adjacent flat surfaces 64b and curved surfaces 64c in the circumferential direction, thereby preventing relative rotation of the bearing 6 around the axis x with respect to the cylinder 71. In other words, the outer circumferential surface 64a of the third portion 64 of the main body 61 of the bearing 6 constitutes a portion that restricts the relative rotation of the bearing 6 around the axis x with respect to the rotating body 7.

[0029] Furthermore, the outer circumferential surface 64a of the third portion 64 of the main body 61 and the inner circumferential surface 71a of the cylinder 71 may have other polygonal shapes such as hexagons, pentagons, or squares in a cross-section perpendicular to the axis x. Also, if the outer circumferential surface 64a of the third portion 64 is formed in a polygonal shape, its corners 64d may be rounded. In this case as well, the inner circumferential surface 71a of the cylinder 71 has a shape corresponding to the shape of the outer circumferential surface 64a of the third portion 64. In addition, as another example, a rib protruding outward may be formed on the outer circumferential surface 64a of the third portion 64, while a groove that engages with the rib may be formed on the inner circumferential surface 71a of the cylinder 71. With such a configuration, the bearing 6 may be provided with a function to prevent rotation of the rotating body 7.

[0030] Returning to Figures 4 to 7, the body 61 of the bearing 6 has a first surface oriented in the axial direction, i.e., an upper end surface 65 and a lower end surface 66, and a second surface, i.e., an inner circumferential surface 67, which faces the outer circumferential surface of the shaft 45 in the radial direction when the rotating body 5 is supported by the shaft 45. The inner circumferential surface 67 is defined as a cylindrical surface centered on the axis x. One or more grooves 67a extending in the axial direction are formed on the inner circumferential surface 67. In this example, four grooves 67a are formed on the inner circumferential surface 67 at predetermined intervals around the axis x. Each groove 67a is recessed from the inner circumferential surface 67 toward the outer circumferential side. Each groove 67a extends from the upper end to the lower end of the cylinder 71. When the bearing 6 is supported by the shaft 45, fluid flows in these grooves 67a.

[0031] The upper end surface 65 and the lower end surface 66 extend, for example, along a plane perpendicular to the axis x. Multiple first dynamic pressure grooves 68 are formed on the upper end surface 65 and the lower end surface 66, respectively, arranged at predetermined intervals in the circumferential direction. Each first dynamic pressure groove 68 is recessed from the upper end surface 65 and the lower end surface 66, respectively. Each first dynamic pressure groove 68 has, on the upper end surface 65 and the lower end surface 66, a first portion 68a extending from the outer circumference to the inner circumference, and a second portion 68b extending from the inner circumference to the outer circumference and intersecting the first portion 68a. In this example, the first portion 68a and the second portion 68b extend while inclining counterclockwise as they intersect with each other when viewed from above in the axial direction. Thus, each first dynamic pressure groove 68 is formed in a so-called herringbone shape.

[0032] In this example, a plurality of second dynamic pressure grooves 69 are formed on the inner circumferential surface 67, adjacent to the upper and lower ends of the cylinder 71, respectively. The plurality of second dynamic pressure grooves 69 are arranged at predetermined intervals in the circumferential direction. Each second dynamic pressure groove 69 is recessed from the inner circumferential surface 67 toward the outer circumference. Each second dynamic pressure groove 69 has, at the upper and lower ends of the cylinder 71, a first portion 69a extending from the bottom to the top, and a second portion 69b extending from the top to the bottom and intersecting the first portion 69a. In this example, the first portion 69a and the second portion 69b extend while inclining counterclockwise toward the portions that intersect each other when viewed from the upper axial side. Thus, each second dynamic pressure groove 69 is formed in a so-called herringbone shape.

[0033] Specifically, the first portion 69a extends in a first direction D1 in the circumferential direction around the axis x, while the second portion 69b extends in a second direction D2 that intersects the first direction D1 in the circumferential direction. In this example, the first direction D1 and the second direction D2 intersect each other at an angle of 45 degrees, for example. Also, for example, eight second dynamic pressure grooves 69 are arranged at equal intervals in the circumferential direction. Furthermore, as shown in Figure 7, in one example, the height H1 of the first portion 69a in the axial direction and the height H2 of the second portion 69b in the axial direction are set to be the same. Height H1 is the height from the upper end to the lower end of the first portion 69a, and height H2 is the height from the upper end to the lower end of the second portion 69b. The adjustment of these heights H1 and H2 will be described later.

[0034] As mentioned above, the bearing 6 is formed by injection molding from a thermoplastic resin material, such as super engineering plastic. The grooves 67a and the second dynamic pressure groove 69 formed on the inner circumferential surface 67 of the main body 61 are formed by transferring the uneven pattern formed on the outer surface of a pin placed in the mold during injection molding. After the grooves 67a and the second dynamic pressure groove 69 are formed by transferring the uneven pattern, the pin is forcibly removed from the main body 61 at a predetermined timing. The bearing 6 is thus formed.

[0035] Figure 9 is a perspective cross-sectional view of the cross-section along the line 9-9 in Figure 7. As shown in Figure 9, the groove 67a on the inner circumferential surface 67 of the main body 61 is formed in a semi-cylindrical shape around a central axis defined parallel to the axis x. The second dynamic pressure groove 69 has a bottom surface defined along a cylindrical surface centered on the axis x. In the radial direction, the depth d2 of the second dynamic pressure groove 69 (second portion 69b) defined from the inner circumferential surface 67 toward the outer circumference is smaller than the depth d1 (in this case, the maximum depth) of the groove 67a defined from the inner circumferential surface 67 toward the outer circumference. Thus, the second dynamic pressure groove 69 is partially divided by the groove 67a in the circumferential direction.

[0036] Returning to Figure 2, in the axial direction, a predetermined gap is secured between the upper end of the bearing 6 and the lower surface of the support portion 34, and between the lower end of the bearing 6 and the bottom wall 41. The first flange 72 and blades 73 of the rotor 76 are housed in the first space S1, while the magnet 8 is housed in the second space S2. In the axial and radial directions, the blades 73 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 8 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 8 faces the bottom wall 41 with a predetermined gap between them.

[0037] Figure 10 is a cross-sectional view along the line 10-10 in Figure 2. Referring to both Figure 2 and Figure 10, the pump device 1 includes a stator 9 incorporated into the can section 4. Specifically, the stator 9 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 9 includes a stator core 91, a plurality of coils 92, and an insulator 93. The stator core 91 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 92 have windings, for example, made of copper wire. The insulator 93 electrically insulates the stator core 91 from the plurality of coils 92. The insulator 93 is made of an insulating material, for example, a resin material.

[0038] The stator core 91 comprises an annular portion 94 and a plurality of teeth 95. The annular portion 94 is fixed to the inner circumferential surface of the outer wall 44 of the can portion 4. The annular portion 94 is defined in an annular shape around the axis x. Each tooth 95 protrudes inward from the inner circumferential surface of the annular portion 94. Each tooth 95 faces the outer circumferential surface of the magnet 8 of the rotor 76 with a predetermined magnetic gap, with the inner wall 42 of the can portion 4 in between. The insulator 93 covering each tooth 95 is wound with the windings of a coil 92. In this example, there are 12 teeth 95, but the number of teeth 95 can be any number, such as 6 or 18. The number of poles of the rotor 76 can also be changed in accordance with the change in the number of teeth 95.

[0039] In the pump device 1, when current is supplied to the coil 92, the magnetic interaction between the coil 92 and the magnet 8 causes the rotor 76, or rotating body 5, to rotate clockwise around its axis x. This rotation generates a flow of coolant from the inlet 32 ​​into the first space S1 via multiple blades 73. The coolant flows outwards through the multiple blades 73 and then exits through 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.

[0040] When the rotating body 5, i.e., the bearing 6, rotates around axis x, fluid flows into the first dynamic pressure groove 68 at the upper end surface 65 and lower end surface 66 of the main body 61 of the bearing 6. In the first dynamic pressure groove 68, fluid flows from the outer circumference end of the first portion 68a and the inner circumference end of the second portion 68b toward the point where the first portion 68a and the second portion 68b intersect. As the fluid accumulates near the intersection, a high pressure is generated near the intersection. This pressure ensures a predetermined gap between the upper end surface 65 of the bearing 6 and the lower surface of the support portion 34, and between the lower end surface 66 and the upper surface of the bottom wall 41.

[0041] Furthermore, fluid flows into the second dynamic pressure groove 69 on the inner circumferential surface 67 of the bearing body 61. In the second dynamic pressure groove 69, fluid flows from the lower end of the first portion 69a and the upper end of the second portion 69b toward the point where the first portion 69a and the second portion 69b intersect. As the fluid accumulates near the intersection, a high pressure is generated in that area. This pressure ensures a predetermined gap between the inner circumferential surface 67 of the bearing 6 and the outer circumferential surface of the shaft 45. In this way, the upper end of the body 61 and the pair of adjacent second dynamic pressure grooves 69 constitute a fluid sliding bearing.

[0042] Furthermore, fluid flows into four grooves 67a on the inner circumferential surface 67 of the bearing body 61. Specifically, the fluid flows through the grooves 67a, for example, from the upper end to the lower end of the body 61, or from the lower end to the upper end of the body 61. Here, as shown in Figure 7, if, for example, the height H1 of the first portion 69a of the second dynamic pressure groove 69 is set to be greater than the height H2 of the second portion 69b, then the amount of fluid flowing through the first portion 69a of the second dynamic pressure groove 69 will be greater than the amount of fluid flowing through the second portion 69b. As a result, the fluid flow between the bearing 61 and the shaft 45 can be set in the direction from the lower end to the upper end of the body 61. Note that the angle at which the first direction D1 and the second direction D2 intersect does not change. In this way, the fluid flow can be controlled by offsetting the position where the first portion 69a and the second portion 69b intersect in the axial direction.

[0043] On the other hand, if, for example, the height H1 of the first portion 69a of the second dynamic pressure groove 69 is set to be smaller than the height H2 of the second portion 69b, then the amount of fluid flowing in the second portion 69b of the second dynamic pressure groove 69 will be greater than the amount of fluid flowing in the first portion 69a. As a result, the fluid flow can be set to proceed from the upper end to the lower end of the main body 61. Note that the angle at which the first direction D1 and the second direction D2 intersect does not change. Furthermore, as will be described later, since an upward thrust force acts on the rotating body 5, i.e., the bearing 6, in the axial direction, it is preferable to set the height H1 of the first portion 69a of the main body 61 to be larger than the height H2 of the second portion 69b, thereby setting the fluid flow to proceed from the lower end to the upper end of the main body 61.

[0044] In the pump device 1 as described above, the bearing 6 is formed of a resin material such as PEEK, a super engineering plastic having higher slidability than the resin material of the rotating body main body 7. Further, a second dynamic pressure groove 69 that constitutes a fluid bearing is formed on the inner peripheral surface 67 of the bearing 6. As a result, when the bearing 6 rotates, high slidability is ensured even when the inner peripheral surface 67 of the bearing 6 contacts the outer peripheral surface of the shaft 45. Therefore, the wear resistance and reliability of the bearing 6 can be improved. Moreover, since the main body 61 of the bearing 6 has an outer peripheral surface 64a having a plurality of corners 64d, rotation of the bearing 6 around the axis x with respect to the cylinder 71 of the rotating body main body 7 can be reliably prevented. Note that, as long as it has higher slidability than the resin material of the rotating body main body 7, a resin material other than PEEK may be used for the bearing 6.

[0045] Also, in the bearing 6 incorporated in the pump device 1, formation of the first dynamic pressure groove 68 on the lower end surface 66 of the main body 61 may be omitted. In the pump device 1, the coolant flows into the first space S1 from the inflow portion 32 by the rotation of the blades 73 of the rotating body 5. On the other hand, although the coolant also flows into the second space S2, there is no escape space for the coolant in the second space S2, so the pressure in the second space S2 becomes higher than that in the first space S1. Due to this pressure difference, an upward thrust force is applied to the rotating body 5, that is, the bearing 6 in the axial direction. As a result, a relatively large gap is likely to be secured between the lower end surface 66 of the bearing 6 and the upper surface of the bottom wall 41, so the first dynamic pressure groove 68 may not be formed on the lower end surface 66.

[0046] As described above, the present invention has been described through the above embodiments, but the technical scope of the present invention is not limited to the scope described in the above embodiments. It is obvious to those skilled in the art that various changes or improvements can be made to the above embodiments. It is clear from the description of the claims that forms with such changes or improvements can also be included in the technical scope of the present invention.

[0047] The embodiments described above are for facilitating the understanding of the present invention and are not for limiting and interpreting the present invention. Further, the above-described embodiments do not limit the objects to which the present invention is applied, and the present invention may include any object as its application target. Each component included in the above embodiments, as well as its arrangement, material, conditions, shape, size, etc. are not limited to those illustrated and can be changed as appropriate.

[0048] For example, the present invention includes differences that occur in the implementation of manufacturing tolerances and the like. Also, within a technically non-contradictory range, components shown in different embodiments can be partially substituted or combined with each other. Further, each configuration can be selectively combined as appropriate so as to achieve at least part of the above-described problems and effects.

[0049] 1. Pump device, 2. Casing, 3. Case, 31. Body, 32. Inlet portion, 33. Outlet portion, 34. Support portion, 35. Spoke, 36. Recess, 4. Can portion, 41. Bottom wall, 41a. Through hole, 42. Inner wall, 43. Top wall, 44. Outer wall, 45. Shaft, 5. Rotating body, 6. Bearing (first resin member), 61. Body, 62. First portion, 62a. Outer peripheral surface, 63. Second portion, 63a. Outer peripheral surface, 64. Third portion (portion formed in a polygonal shape), 64a. Outer peripheral surface (portion that restricts relative rotation of the first resin member with respect to the second resin member), 64b. Flat surface, 64c. Curved surface, 65. Upper end surface, 66. Lower end surface, 67. Inner peripheral surface, 67a. Groove, 68. First dynamic pressure groove, 68a. First portion, 68b. Second portion, 69. Second dynamic pressure groove, 69a. First portion, 69b. Second portion, 7. Rotating body main body (second resin member), 71. Cylinder, 72. First flange, 73. Blade, 74. Second flange, 75. Side wall, 76. Rotor, 77. Impeller, 8. Magnet, 9. Stator, 91. Stator core, 92. Coil, 93. Insulator, 94. Annular portion, 95. Teeth, D1. First direction, D2. Second direction, d1, d2. Depth, H1, H2. Height, L1 to L6. Length, S. Internal space, S1. First space, S2. Second space, x. Axis

Claims

1. A rotating body comprising: a first resin member rotatably supported with respect to a shaft; and a second resin member made of thermoplastic resin fixed to the first resin member, wherein the outer circumferential surface of the first resin member includes a portion that restricts the relative rotation of the first resin member with respect to the second resin member, and the first resin member has higher sliding properties than the second resin member.

2. The rotating body according to claim 1, wherein the second resin member has a rotor and an impeller arranged in the axial direction, and the first resin member extends from the rotor to the impeller.

3. The rotating body according to claim 2, wherein the length of the first resin member in the axial direction is longer than the length of the rotor in the axial direction.

4. The rotating body according to claim 3, wherein, in the axial direction, the first resin member comprises a first annular portion located on the impeller side, a second annular portion located on the rotor side, and a polygonal portion positioned between the first and second portions, wherein, in the axial direction, the first portion is longer than the second portion.

5. A pump device comprising: a rotating body according to any one of claims 1 to 4; and a casing through which a fluid flows, wherein the first resin member and the second resin member are housed in the casing, and the first resin member comprises: a first surface facing axially and a second surface facing the shaft in the radial direction, the first surface having a first dynamic pressure groove, and the second surface having a groove extending in the axial direction, through which the fluid flows.

6. The pump device according to claim 5, wherein the second surface is provided with a second dynamic pressure groove extending in the circumferential direction, the depth of the second dynamic pressure groove is smaller than the depth of the groove in the radial direction, and of the second dynamic pressure groove, the first groove extends in a first direction and the second groove extends in a second direction intersecting the first direction in the circumferential direction.

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