Pump device

Abstract

This invention provides a pump device that suppresses the increase in driving torque caused by the viscous resistance of fluids at low temperatures and suppresses the increase in power consumption when using an electric motor as the drive source. The pump device includes: a drive shaft centered on the axis; an inner rotor connected to the drive shaft and an outer rotor rotating in conjunction with the inner rotor; and a housing comprising a fluid intake port, an exhaust port, and a receiving chamber that houses the inner and outer rotors and defines opposing surfaces perpendicular to the axis in an adjacent and opposing manner. The pump device includes an inner opposing region where the inner rotor and the opposing surface are adjacent and opposing in the axial direction, and an outer opposing region where the outer rotor and the opposing surface are adjacent and opposing in the axial direction. The outer opposing region includes a gap enlargement region with a larger gap than the inner opposing region.

Description

Technical Field

[0001] The present invention relates to a pump device including a pump unit that applies pumping action to a fluid, and more particularly to a pump device comprising an inner rotor and an outer rotor that apply pumping action to a viscous fluid such as hydraulic oil or lubricating oil. Background Technology

[0002] As an existing pump device, an oil pump forming a trochoid pump is known, the trochoid pump comprising: a main housing forming a cylindrical receiving space; an outer rotor having internal teeth and rotatably inserted into the receiving space; an inner rotor having external teeth meshing with the internal teeth and rotatably disposed within the outer rotor; a drive shaft for rotating the inner rotor; and a cover assembled on the main housing to cover the opening of the main housing, the cover being formed of a metal plate having undergone a sliding properties enhancement treatment (for example, see Patent Document 1).

[0003] In the oil pump, in the axial direction of the drive shaft, the two end faces of the inner rotor and the outer rotor are arranged such that the inner wall surface of the opposing surface forming the main housing is adjacent to and faces the inner wall surface of the opposing surface forming the cover.

[0004] In the aforementioned configuration, if the viscosity of the oil increases at low temperatures, the driving torque required to rotate the inner and outer rotors increases due to viscous resistance. This results in increased power consumption, especially when an electric motor is used as the drive source, and requires electronic components capable of withstanding high currents.

[0005] In addition, as another existing pump device, a cycloidal pump is known, comprising: a pump housing body having a recessed circular rotor receiving portion; an outer rotor having internal teeth and rotatably inserted into the rotor receiving portion; an inner rotor having external teeth and rotatably disposed within the outer rotor; a drive shaft for rotating the inner rotor; and a pump base connected to the pump housing body to cover the opening of the pump housing body, wherein two annular grooves are provided on the inner circumferential surface of the rotor receiving portion of the pump housing body to reduce the contact area between the inner circumferential surface and the outer circumferential surface of the outer rotor (for example, see Patent Document 2).

[0006] In the aforementioned cycloidal pump, in the axial direction of the drive shaft, the two end faces of the inner rotor and the outer rotor are arranged such that the inner wall surface of the opposing surface forming the pump housing body is adjacent to and faces the inner wall surface of the opposing surface forming the pump base.

[0007] In the aforementioned configuration, if the viscosity of the oil increases at low temperatures, the driving torque required to rotate the internal and external rotors increases due to viscous resistance. This results in increased power consumption, especially when an electric motor is used as the drive source, and requires electronic components capable of withstanding high currents.

[0008] [Existing technical documents]

[0009] [Patent Literature]

[0010] [Patent Document 1] Japanese Patent Application Publication No. 2018-105291

[0011] [Patent Document 2] Japanese Patent Application Publication No. 2011-214553 Summary of the Invention

[0012] [The problem the invention aims to solve]

[0013] The present invention was made in view of the above circumstances, and its object is to provide a pump device that, when drawing in and ejecting fluids at low temperatures, suppresses and reduces the increase in driving torque caused by the viscous resistance of the fluid, and suppresses the increase in power consumption when using an electric motor as the drive source, without requiring electronic components with high rated current, etc.

[0014] [Technical means to solve the problem]

[0015] The pump device of the present invention comprises: a drive shaft centered on a predetermined axis; an inner rotor connected to the drive shaft for applying a pumping action to a fluid and an outer rotor rotating in conjunction with the inner rotor; and a housing comprising a fluid intake port, an exhaust port, and a receiving chamber that houses the inner rotor and the outer rotor and defines opposing surfaces perpendicular to the axis in an adjacent and opposing manner. The pump device includes an inner opposing region in which the inner rotor and the opposing surface are adjacent and opposing in the axial direction, and an outer opposing region in which the outer rotor and the opposing surface are adjacent and opposing in the axial direction. The outer opposing region includes a gap enlargement region with a larger gap than the inner opposing region.

[0016] The pump device can be structured such that the gap enlargement region is defined between the outer rotor, which is narrower than the inner rotor in the axial direction, and the opposing surface.

[0017] The pump device may be structured such that the gap enlargement region is formed on one end side and the other end side facing the outer rotor in the axial direction.

[0018] The pump device may employ a structure in which the opposing surfaces of the receiving chamber include a main opposing surface adjacent to and facing the inner rotor, and a concave opposing surface formed by being recessed further in the axial direction than the main opposing surface, and the gap enlargement area is defined between the outer rotor and the concave opposing surface.

[0019] The pump assembly may employ a structure in which the concave facing surfaces are formed in an annular shape in a region radially outward from the tooth line of the outer rotor.

[0020] The pump device may be structured such that the gap enlargement region is formed on one end side and the other end side facing the outer rotor in the axial direction.

[0021] The pump device can be structured such that when the total gap between the two sides of the inner opposing region is set as Ci and the gap between the two sides of the outer opposing region is set as Co, the gap ratio Co / Ci is 1.3 or higher.

[0022] The pump device may be configured such that the suction port and the discharge port are formed as opposing surfaces facing one side of the containment chamber.

[0023] The pump device may employ a structure in which a recess is formed in the axial direction on the opposite side of the receiving chamber to temporarily store fluid.

[0024] The pump assembly may employ a structure in which the housing comprises: a housing body having a cylindrical recess that rotatably accommodates an outer rotor and an inner rotor and defines opposing surfaces; and a housing cover that engages with the housing body to define a receiving chamber and defines opposing surfaces, the housing cover comprising: a suction port, an intake port formed adjacent to the suction port and for drawing fluid from the outside, an exhaust port, and an exhaust port formed adjacent to the exhaust port and for discharging fluid to the outside.

[0025] The pump assembly may employ a structure in which the inner and outer rotors are cycloidal pumps with tooth profiles based on a cycloidal curve.

[0026] The pump device may include an electric motor that applies a rotational driving force to the drive shaft.

[0027] [The effects of the invention]

[0028] According to the pump device that forms the structure described above, when drawing in and ejecting fluids at low temperatures, the increase in driving torque caused by the viscous resistance of the fluid can be suppressed and reduced. Furthermore, when using an electric motor as the drive source, the increase in power consumption can be suppressed. The device can be miniaturized and reduced in cost by eliminating the need for electronic components with high rated current. Attached Figure Description

[0029] Figure 1 This is a perspective view showing the external appearance of the pump device according to the first embodiment of the present invention.

[0030] Figure 2 This is a cross-sectional view showing the state of the pump device of the first embodiment installed on the object to which it is applied.

[0031] Figure 3 This is an exploded perspective view of the pump device of the first embodiment when disassembled and viewed from the housing body side.

[0032] Figure 4 This is an exploded perspective view of the pump device of the first embodiment when disassembled and viewed from the side of the outer cover.

[0033] Figure 5 This is an exploded perspective view showing the housing body, drive shaft, inner rotor and outer rotor, and housing cover included in the pump device of the first embodiment.

[0034] Figure 6 This is a partial end view of the pump device in the first embodiment when the housing cover is removed and viewed from the axial direction of the drive shaft.

[0035] Figure 7 It means in Figure 6 A partial end view of the inner and outer rotors removed in the state shown.

[0036] Figure 8 This is an exploded perspective view showing the drive shaft, inner rotor, outer rotor, and housing included in the pump device of the first embodiment.

[0037] Figure 9 It is a diagram showing the relationship between the inner rotor and the outer rotor and the housing in the pump device of the first embodiment, and is a plan view viewed from the inside in the axial direction.

[0038] Figure 10 It means in Figure 9 The diagram shows a plan view of the opposing surfaces perpendicular to the axis after removing the inner and outer rotors in the shown state.

[0039] Figure 11 This is a partial cross-sectional view showing the area of ​​the inner rotor and outer rotor arranged in the housing chamber of the pump device in the first embodiment, cut off with a plane including the axis.

[0040] Figure 12 This is a schematic diagram showing the relationship between the inner rotor, the outer rotor, and the opposing surfaces perpendicular to the axes on both sides of the housing in the pump device of the first embodiment.

[0041] Figure 13 It is a graph showing the rate of change of the clearance ratio (the gap between the outer rotor and the opposing surface / the gap between the inner rotor and the opposing surface) with respect to the driving torque and the ejection flow rate in the pump device of the first embodiment.

[0042] Figure 14 This is an exploded perspective view showing the housing body, drive shaft, inner rotor and outer rotor, and housing cover included in the pump device according to the second embodiment of the present invention.

[0043] Figure 15 This is a partial end view of the pump device in the second embodiment when the housing cover is removed and viewed from the axial direction of the drive shaft.

[0044] Figure 16 It means in Figure 15 A partial end view of the inner and outer rotors removed in the state shown.

[0045] Figure 17 This is an exploded perspective view showing the drive shaft, inner rotor, outer rotor, and housing included in the pump device of the second embodiment.

[0046] Figure 18 This is a diagram showing the relationship between the inner rotor and the outer rotor and the housing in the pump device of the second embodiment, and it is a plan view viewed from the inside in the axial direction.

[0047] Figure 19 It means in Figure 18 The diagram shows a plan view of the opposing surfaces perpendicular to the axis after removing the inner and outer rotors in the shown state.

[0048] Figure 20 This is a partial cross-sectional view showing the area of ​​the inner rotor and outer rotor arranged in the housing chamber of the pump device in the second embodiment, cut off with a plane including the axis.

[0049] Figure 21 This is a schematic diagram showing the relationship between the inner rotor, the outer rotor, and the opposing surfaces perpendicular to the axes on both sides of the housing in the pump device of the second embodiment.

[0050] Explanation of icon numbers

[0051] 1: Application Objects

[0052] 1a: Joint

[0053] 1b, 15: Fitting recess

[0054] 1c: Storage section

[0055] 1d: Import pathway

[0056] 10, 110: Shell body

[0057] 11, 111: Recessed part of cylinder

[0058] 11a, 13a: Inner circumferential surface

[0059] 11b, 111b: Opposing surfaces (opposing surfaces on the other side)

[0060] 11c: concave part

[0061] 12, 16a, 16b, 31, 35, 41: Joint surfaces

[0062] 12a, 16c: Threaded holes

[0063] 13: Motor Storage Department

[0064] 14: Through hole

[0065] 16: Flange portion

[0066] 16a1, 31a, 35a: Annular groove

[0067] 17, 36: convex section

[0068] 20, 120: Shell cover

[0069] 21, 22: Cylinder section

[0070] 21a: Inlet

[0071] 22a: Exhaust outlet

[0072] 23, 123: Opposing surfaces (opposing surfaces on one side)

[0073] 24: Inhalation Port

[0074] 25: Ejection Port

[0075] 26: Central concave part

[0076] 27, 37, 43: Round holes

[0077] 30: Motor cover

[0078] 32: Fitting convex part

[0079] 33: Bearing cylindrical section

[0080] 34: Opening

[0081] 38: Connector Section

[0082] 40: Outer cover

[0083] 42: Containment Department

[0084] 50: Electric motor

[0085] 51: Stator

[0086] 52: Rotor

[0087] 60: Drive shaft

[0088] 70, 170: Pump unit

[0089] 71, 171: Internal rotor

[0090] 71a, 71b, 72a, 72b, 171a, 171b, 172a, 172b: End faces

[0091] 71c, 171c: Fitting hole

[0092] 71d, 171d: External teeth (dental row)

[0093] 72, 172: External rotor

[0094] 72c, 172c: outer peripheral surface

[0095] 72d, 172d: Internal teeth (tooth row)

[0096] 80: Circuit board

[0097] 111b1, 123a: Principal facing planes

[0098] 111b2, 123b: Concave facing surfaces

[0099] Ace: Gap widening area

[0100] Ai1, Ai2: Inner opposing regions

[0101] Ao1, Ao2: Outer opposing regions

[0102] B1, B2: Bearings

[0103] b1, b2, b3: Screws

[0104] Ci: Total gap (clearance) between the two sides of the inner opposing regions.

[0105] Ci1, Ci2: The gap between the inner opposing regions (gap)

[0106] Co: Total gap (gap) between the two sides of the outer opposing regions.

[0107] Co1, Co2: The gap between the outer, opposing regions (gap)

[0108] D: The department being tested

[0109] H, H2: Shell

[0110] M, M2: Pump unit

[0111] Pc: Containment Chamber

[0112] S, S2: Axis

[0113] Sb: Thrust bearing

[0114] Sr: Lip seal component

[0115] SR1, SR2, SR3: Sealing components

[0116] W1: Width dimension of the inner rotor

[0117] W2: Width dimension of the outer rotor Detailed Implementation

[0118] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0119] The pump device M in the first embodiment is a built-in electric pump device that delivers hydraulic oil as a fluid, such as... Figures 1 to 4 As shown, it includes: housing body 10, housing cover 20, motor cover 30, outer cover 40, electric motor 50, drive shaft 60 centered on axis S, pump unit 70 including inner rotor 71 and outer rotor 72, and circuit board 80.

[0120] Here, the housing H of the pump device M includes a housing body 10, a housing cover 20, and an outer cover 40.

[0121] In addition, such as Figure 2 As shown, the object 1 of the application of the pump device M includes: a joint 1a forming a plane perpendicular to the axis S of the pump device M, a fitting recess 1b, a hydraulic oil storage part 1c, an inlet passage 1d for guiding the hydraulic oil to the supply destination, and four threaded holes (not shown) for the installation screws to be screwed in.

[0122] Application objects include, for example, the cooling and lubrication systems of vehicle transmissions, engine cooling and lubrication systems, and other devices that require the circulation of hydraulic oil.

[0123] The shell body 10 is formed using metal materials such as steel, cast iron, sintered steel, and aluminum alloy, for example... Figures 3 to 5 As shown, it includes a cylindrical recess 11, a mating surface 12, a motor housing 13, an insertion hole 14 through the drive shaft 60, a fitting recess 15, a flange 16, and four bosses 17.

[0124] The cylindrical recess 11 is a region that defines a portion of the receiving chamber Pc that rotatably houses the pump unit 70, such as Figures 5 to 7 As shown, it includes an inner circumferential surface 11a, opposing surfaces 11b perpendicular to the axis S, and two recesses 11c.

[0125] The inner circumferential surface 11a forms a cylindrical surface centered on an axis S2 that is offset parallel to the axis S, and slidably supports the outer circumferential surface 72c of the outer rotor 72, which forms part of the pump unit 70. Here, "slidably" means the region of fluid lubrication in the Stribeck curve when there is an oil film of hydraulic oil as a fluid in between, for example, a state in which the gap is formed from several μm to tens of μm.

[0126] The opposing surface 11b is a plane that forms the bottom surface of the cylindrical recess 11 and is perpendicular to the axis S. It is a region that is adjacent to and faces the end faces 71a and 72a on the inner side (other side) of the pump unit 70 (inner rotor 71 and outer rotor 72) in the direction of the axis S. Furthermore, the term "adjacent and facing" refers to the region of fluid lubrication in the Stricker curve when there is an oil film of hydraulic oil as a fluid in between, for example, a state in which the gap is formed from several μm to tens of μm.

[0127] Here, in Figure 7 In the diagram, the area enclosed by a circle with a double-dotted line centered on axis S represents the range of the inner opposing region Ai1 where the end face 71a of the inner rotor 71 and the opposing face 11b are adjacent and facing each other in the direction of axis S.

[0128] In addition, Figure 7 In the diagram, the area enclosed by two circles with double-dotted lines centered on axis S2 represents the range of the outer opposing region Ao1 where the end face 72a of the outer rotor 72 and the opposing face 11b are adjacent and facing each other in the direction of axis S.

[0129] The recess 11c is formed by being recessed in the direction of axis S relative to the opposing surface 11b, and is a region where hydraulic oil that flows into the receiving chamber Pc is temporarily stored.

[0130] The mating surface 12 is formed as an annular plane perpendicular to the axis S to engage the housing cover 20 covering the cylindrical recess 11, including three threaded holes 12a into which the screw b1 for fastening the housing cover 20 is screwed.

[0131] The motor housing 13 is the area that houses the electric motor 50, including an inner circumferential surface 13a in which the stator 51 of the electric motor 50 is fitted and fixed. On the inner side of the inner circumferential surface 13a, there are inner circumferential surfaces in which a bearing B1 for rotatably supporting the drive shaft 60 is fitted, and an inner circumferential surface in which a lip seal member Sr is fitted. The lip seal member Sr cooperates with the bearing B1 to clamp the thrust bearing Sb and seal the area around the drive shaft 60.

[0132] The through hole 14 is the area through which the drive shaft 60 passes, and a cylindrical hole centered on the axis S is formed in the wall portion that separates the cylindrical recess 11 from the motor housing portion 13.

[0133] The fitting recess 15 is formed as a cylindrical surface centered on the axis S in the outer end region of the motor housing portion 13, and the fitting protrusion 32 of the motor cover 30 is fitted therein. By fitting the fitting protrusion 32 of the motor cover 30 into the fitting recess 15, the center of the bearing cylindrical portion 33 formed in the motor cover 30 is positioned on the same axis as the axis S of the housing body 10.

[0134] The flange portion 16 is formed by protruding in a flat plate shape from the wall portion of the defined motor housing portion 13 in a direction perpendicular to the axis S, and includes a mating surface 16a, a mating surface 16b, an outer cover 40, and four threaded holes 16c for screws b3 for fastening the motor cover 30.

[0135] The mating surface 16a is formed as a plane perpendicular to the axis S to engage with the joint portion 1a of the object 1. Additionally, an annular groove 16a1 is formed on the mating surface 16a to allow the sealing member SR3, which exists between the mating surface and the joint portion 1a, to be embedded. Furthermore, the sealing member SR3 is an O-ring made of rubber material.

[0136] The mating surface 16b clamps the sealing member SR1 and is formed into a plane perpendicular to the axis S to engage the motor cover 30.

[0137] The boss portion 17 includes a round hole through which a mounting screw for mounting the housing body 10 to the joint 1a of the application object 1 passes.

[0138] The housing cover 20 is engaged with the housing body 10 in a manner that covers the cylindrical recess 11, and cooperates with the cylindrical recess 11 of the housing body 10 to define the receiving chamber Pc. It is formed into a flat plate shape using materials such as steel, cast iron, sintered steel, and aluminum alloy.

[0139] Moreover, such as Figure 5 , Figures 8 to 10 As shown, the housing cover 20 includes a cylindrical portion 21, a cylindrical portion 22, an opposing surface 23 perpendicular to the axis S, an intake port 24, an exhaust port 25, a central recess 26 for receiving the front end of the drive shaft 60, and three round holes 27 through which a fastening screw b1 passes.

[0140] The cylinder 21 is designated with a suction port 21a for drawing in hydraulic oil and is disposed in the storage section 1c of the object to be applied 1.

[0141] The cylinder 22 is designed to spray out hydraulic oil through an outlet 22a and is fitted into the inlet passage 1d of the object 1.

[0142] The opposing surface 23 is formed as a plane perpendicular to the axis S, and is the region adjacent to and facing the end faces 71b and 72b on the outer side (one side) of the pump unit 70 (inner rotor 71 and outer rotor 72) in the direction of the axis S. Furthermore, the term "adjacent and facing" similarly refers to the fluid-lubricated region in the Stricker curve, where an oil film of hydraulic oil as a fluid exists as a barrier, for example, a gap of several μm to tens of μm.

[0143] Here, in Figure 10In the diagram, the area enclosed by a circle with a double-dotted line centered on axis S represents the range of the inner opposing region Ai2, where the end face 71b of the inner rotor 71 and the opposing surface 23 are adjacent to and facing each other in the direction of axis S.

[0144] In addition, Figure 10 In the diagram, the area enclosed by two circles with double-dotted lines centered on axis S2 represents the range of the outer opposing region Ao2 where the end face 72b of the outer rotor 72 and the opposing surface 23 are adjacent to and facing each other in the direction of axis S.

[0145] The suction port 24 is formed by opening the opposing surface 23 and is located in the area where hydraulic oil is drawn into the containment chamber Pc. It is formed adjacent to the suction port 21a. That is, the suction port 24 is formed as an opposing surface 23 facing one side of the containment chamber Pc.

[0146] The ejection port 25 is formed by opening the opposing surface 23, and is located adjacent to the ejection outlet 22a in the area where pressurized hydraulic oil is ejected from the containment chamber Pc. That is, the ejection port 25 is formed as an opposing surface 23 facing one side of the containment chamber Pc.

[0147] Furthermore, with the pump unit 70 housed in the cylindrical recess 11, the outer peripheral region of the facing surface 23 of the housing cover 20 is joined to the mating surface 12 of the housing body 10 and fixed to the housing body 10 by screws b1. That is, the housing chamber Pc for housing the pump unit 70 is defined by the cylindrical recess 11 of the housing body 10 and the facing surface 23 of the housing cover 20.

[0148] The motor cover 30 is joined to the housing body 10 to cover the motor housing portion 13 of the housing body 10, and is formed using a resin material, such as... Figure 3 and Figure 4 As shown, it includes a mating surface 31, a fitting protrusion 32, a bearing cylindrical portion 33, an opening 34, a mating surface 35, a six-bore portion 36 having threaded holes into which screws b2 for fastening the circuit board 80 are screwed, four round holes 37 through which screws b3 pass, and a connector portion 38 for embedding terminals.

[0149] The mating surface 31 is formed as a plane perpendicular to the axis S to engage with the mating surface 16b of the housing body 10. Additionally, an annular groove 31a, in which a sealing member SR1 is disposed, is formed on the mating surface 31. Furthermore, the sealing member SR1 is a ring-shaped molded rubber formed of rubber material or a liquid sealing material injected during engagement.

[0150] The fitting protrusion 32 fits into the fitting recess 15 of the housing body 10, forming a cylindrical shape centered on the axis S, so as to position the center of the bearing cylindrical portion 33 on the axis S.

[0151] The bearing cylindrical part 33 is formed by pressing in a metal molded article with a cylindrical surface defined around the axis S, so as to fit and fix the bearing B2 that supports the drive shaft 60.

[0152] The opening 34 is formed as a circular hole on the same shaft as the bearing cylinder 33, so that the detected part D provided at the end of the drive shaft 60 faces the detection sensor (not shown) provided on the circuit board 80.

[0153] The mating surface 35 is formed as a plane perpendicular to the axis S to engage with the mating surface 41 of the outer cover 40. Additionally, an annular groove 35a, in which a sealing member SR2 is disposed, is formed on the mating surface 35. Furthermore, the sealing member SR2 is a ring-shaped molded rubber formed of rubber material or a liquid sealing material injected during engagement.

[0154] The outer cover 40 covers the circuit board 80 disposed on the outside of the motor cover 30, and is formed using a resin material, such as... Figure 3 and Figure 4 As shown, it includes a mating surface 41 that engages with the mating surface 35 of the motor cover 30, a receiving portion 42 that houses the circuit board 80, and four round holes 43 through which screws b3 pass.

[0155] Furthermore, with the circuit board 80 mounted on the motor cover 30, the outer cover 40 has its mating surface 41 joined to the mating surface 35 of the motor cover 30 and fixed to the housing body 10 by screws b3.

[0156] like Figure 3 and Figure 4 As shown, the electric motor 50 is a three-phase brushless motor including a stator 51 and a rotor 52.

[0157] The stator 51 includes a stator core formed using a steel plate containing magnetic material, a bobbin formed using an electrically insulating resin material, and a coil wound around the bobbin.

[0158] The rotor 52 includes a rotor core formed using a steel plate containing magnetic material and a permanent magnet embedded in the rotor core.

[0159] The drive shaft 60 is made of steel or the like and is formed into a cylindrical shape that extends along the axis S. It is fitted into the rotor 52 in such a way that it rotates integrally with the rotor 52. Moreover, on both sides of the drive shaft 60 that clamp the rotor 52, one side is supported by a bearing B1 fixed to the housing body 10 and the other side is supported by a bearing B2 fixed to the motor cover 30, so that it can rotate freely around the axis S.

[0160] In addition, the area of ​​the drive shaft 60 that is further from the front end than the bearing B1 engages with the fitting hole 71c of the inner rotor 71, transmitting the rotational driving force to the pump unit 70.

[0161] Furthermore, on the drive shaft 60, a lip seal member Sr is disposed in the outer peripheral region between the bearing B1 and the through hole 14, so that hydraulic oil is not allowed to flow from the cylindrical recess 11 (receiving chamber Pc) side toward the motor receiving part 13, or air is not drawn in from the motor receiving part 13 side toward the cylindrical recess 11 side.

[0162] Pump unit 70 is disposed in housing Pc to apply a pumping action to the hydraulic oil, such as suction, pressurization, and ejection. Figure 5 , Figure 6 , Figure 8 , Figure 9 , Figure 11 As shown, this is a cycloidal pump that includes an inner rotor 71 and an outer rotor 72.

[0163] The inner rotor 71 is made of metal materials such as steel or sintered steel and is formed into an external gear with a tooth profile based on a cocycloid curve, including an end face 71a and an end face 71b perpendicular to the axis S, a fitting hole 71c for the drive shaft 60 to fit into, and external teeth 71d forming a tooth row on the outer periphery.

[0164] Furthermore, the inner rotor 71, centered on axis S, along... Figure 9 The arrow in the diagram rotates in the same direction as the drive shaft 60.

[0165] like Figure 11 As shown, end face 71a forms a plane perpendicular to axis S, and is configured to be adjacent to and facing the opposing surface 11b of housing body 10 in the direction of axis S. End face 71b forms a plane perpendicular to axis S, and is configured to be adjacent to and facing the opposing surface 23 of housing cover 20 in the direction of axis S. In addition, the width dimension W1 of inner rotor 71 in the direction of axis S is defined by end face 71a and end face 71b.

[0166] The outer rotor 72 is made of metal materials such as steel or sintered steel and is formed into an internal gear with teeth that can mesh with the inner rotor 71. It includes an end face 72a and an end face 72b perpendicular to the axis S, an outer peripheral surface 72c that is radially adjacent to and facing the inner peripheral surface 11a of the cylindrical recess 11, and an inner tooth 72d forming a tooth row on the inner peripheral surface.

[0167] like Figure 11 As shown, end face 72a forms a plane perpendicular to axis S, and is configured to be adjacent to and face the opposing surface 11b of housing body 10 in the direction of axis S. End face 72b forms a plane perpendicular to axis S, and is configured to be adjacent to and face the opposing surface 23 of housing cover 20 in the direction of axis S. In addition, the width dimension W2 of outer rotor 72 in the direction of axis S is defined by end face 72a and end face 72b.

[0168] Here, the width dimension W2 of the outer rotor 72 is smaller than the width dimension W1 of the inner rotor 71 (W2 < W1), that is, it is formed as a narrow width. For example, when the gap between the opposing surface 11b and the end surface 71a is set as Ci1, the gap between the opposing surface 23 and the end surface 71b is set as Ci2, and the total gap (Ci1 + Ci2) on both sides of the inner opposing region Ai1 and the inner opposing region Ai2 is set as Ci, it is set to satisfy W2 = W1 - 0.3 × Ci or W2 < W1 - 0.3 × Ci.

[0169] Furthermore, the outer rotor 72 rotates in conjunction with the inner rotor 71, which rotates around axis S. Simultaneously, it rotates at a slower speed than the inner rotor 71, around axis S2 which is offset from axis S, in the same direction as the inner rotor 71. In addition, through the partial meshing of the inner rotor 71 and the outer rotor 72, a pumping action of suction, pressurization, and ejection is continuously generated between the two.

[0170] Regarding the relationship between the inner rotor 71 and the outer rotor 72 forming the structure and the housing chamber Pc (facing surfaces 11b and 23), as follows: Figure 12 As shown, in the direction of the axis S, the inner rotor 71 has a gap Ci1 defined between the end face 71a and the opposing surface 11b, and a gap Ci2 defined between the end face 71b and the opposing surface 23. That is, the inner rotor 71 and the housing Pc define a total gap Ci (=Ci1+Ci2) on both sides of the inner opposing region Ai1 and the inner opposing region Ai2.

[0171] Furthermore, in the S-axis direction, the outer rotor 72 has a gap Co1 defined between its end face 72a and the opposing surface 11b, and a gap Co2 defined between its end face 72b and the opposing surface 23. That is, the outer rotor 72 and the housing Pc define a total gap Co (=Co1+Co2) on both sides of the outer opposing region Ao1 and the outer opposing region Ao2. Here, the gap ratio Co / Ci is set to 1.3 or higher.

[0172] That is, in the outer facing regions Ao1 and Ao2 of the outer rotor 72 and the facing surfaces 11b and 23 that are adjacent to and facing each other in the direction of axis S, a gap enlargement region Ace is formed, which includes an inner facing region Ai1 and Ai2 of the inner rotor 71 that are adjacent to and facing each other in the direction of axis S.

[0173] Thus, by setting the gap expansion area Ace, the gap Co in the S direction of the outer rotor 72 is made larger than the gap Ci in the S direction of the inner rotor 71, which can especially reduce the driving torque (driving load) of the hydraulic oil at low temperatures.

[0174] Figure 13This is a graph representing the simulation results of the clearance ratio Co / Ci between the outer rotor 72 and the inner rotor 71, the rate of change of the driving torque, and the rate of change of the ejection flow rate at high temperature. For example... Figure 13 As shown, it can be understood that with the increase of the gap ratio Co / Ci, the ejection flow rate at high temperatures does not change significantly, but the driving torque decreases. Therefore, in order to reduce the driving torque at low temperatures, it is preferable to set the gap ratio Co / Ci to 1.3 or higher, taking into account dimensional tolerances, etc.

[0175] Furthermore, for reference, the simulation results are represented by dashed lines when the clearance of the inner rotor 71 is greater than that of the outer rotor 72. It can be understood that increasing the clearance on the inner rotor 71 side does not significantly reduce the driving torque; on the other hand, the ejection flow rate increases. Based on these results, in order to suppress changes in ejection flow rate while reducing driving torque (driving load), it is effective to increase the clearance of the outer rotor 72 rather than the clearance of the inner rotor 71.

[0176] like Figure 4 As shown, the circuit board 80 is formed as a flat plate, with printed wiring and a control unit for controlling the drive of the electric motor 50 and various electronic components (not shown), or a detection sensor (not shown) is mounted on the inner side facing the opening 34 of the motor cover 30. The detection sensor detects the rotational position of the rotor 52 and includes three Hall elements arranged in an arc around the axis S, facing the detected part D in the direction of the axis S.

[0177] As described above, the pump device M according to the first embodiment of the present invention includes: a drive shaft 60 centered on a predetermined axis S; an inner rotor 71 connected to the drive shaft 60 for applying a pumping action to a fluid (hydraulic oil) and an outer rotor 72 that rotates in conjunction with the inner rotor 71; and a housing H containing a fluid intake port 24, an exhaust port 25, and a housing chamber that houses the inner rotor 71 and the outer rotor 72 and defines opposing surfaces 11b and 23 perpendicular to the axis S in an adjacent and opposing manner. Pc, the pump device M includes an inner facing region Ai1 and an inner facing region Ai2 adjacent to and facing each other on the axis S of the inner rotor 71 and facing surfaces 11b and 23, and an outer facing region Ao1 and an outer facing region Ao2 adjacent to and facing surfaces 11b and 23 on the axis S of the outer rotor 72. The outer facing regions Ao1 and Ao2 include a gap enlargement region Ace with a gap larger than that of the inner facing regions Ai1 and Ai2.

[0178] Therefore, when drawing in and ejecting fluids (hydraulic oil) at low temperatures, the increase in driving torque caused by the viscous resistance of the fluid can be suppressed and reduced, and at high temperatures, the change in ejection flow rate can be suppressed (reduced).

[0179] Furthermore, in the pump assembly M, the gap enlargement region Ace is defined between the outer rotor 72, which is formed in the direction of the axis S and has a width narrower than the inner rotor 71 (W2 < W1), and the opposing surfaces 11b and 23.

[0180] Therefore, the gap enlargement region Ace can be easily formed simply by making the width dimension W2 of the outer rotor 72 smaller than the width dimension W1 of the inner rotor 71.

[0181] Furthermore, in the pump assembly M, the gap enlargement region Ace is formed on both sides of the outer rotor 72 in the direction of axis S, on one end side (facing surface 11b side) and the other end side (facing surface 23 side).

[0182] This allows for a significant reduction in driving torque (driving load).

[0183] In addition, in the pump device M, when the total gap between the two sides of the inner opposing regions Ai1 and Ai2 is set to Ci (=Ci1+Ci2) and the total gap between the two sides of the outer opposing regions Ao1 and Ao2 is set to Co (=Co1+Co2), the gap ratio Co / Ci is set to 1.3 or higher.

[0184] Therefore, while taking into account the dimensional tolerances of the parts or suppressing the change in the hydraulic oil injection flow rate at high temperatures, the driving torque (driving load) at low temperatures can be reduced.

[0185] Furthermore, in the pump unit M, the suction port 24 and the discharge port 25 are formed as opposing surfaces 23 facing one side of the containment chamber Pc.

[0186] Therefore, in the configuration where the suction port 24 and the ejection port 25 are open to the opposing surface 23, the driving torque (driving load) at low temperatures can be reduced by providing the gap enlargement area Ace, as described above.

[0187] In addition, in the pump device M, a recess 11c is formed on the opposite surface 11b on the other side of the receiving chamber Pc, which is recessed in the direction of axis S to temporarily store fluid (hydraulic oil).

[0188] Therefore, in the configuration where the recess 11c is formed on the opposing surface 11b, by setting the gap to enlarge the region Ace, as described above, the driving torque (driving load) at low temperatures can be reduced.

[0189] Additionally, in the pump assembly M, the housing H includes: a housing body 10, which includes a cylindrical recess 11 that rotatably accommodates an outer rotor 72 and an inner rotor 71 and defines an opposing surface 11b; and a housing cover 20, which engages with the housing body 10 to define a receiving chamber Pc and defines an opposing surface 23. The housing cover 20 includes a suction port 24, a suction port 21a that is adjacent to the suction port 24 and draws fluid (hydraulic oil) from the outside, a discharge port 25, and a discharge port 22a that is adjacent to the discharge port 25 and sprays fluid (hydraulic oil) to the outside.

[0190] Therefore, the structure of the present invention (the gap enlargement region Ace) can be easily applied to pump devices that have formed existing forms.

[0191] In addition, in the pump assembly M, the inner rotor 71 and the outer rotor 72 are cycloidal pumps with tooth profiles based on cycloidal curves.

[0192] Therefore, the desired ejection flow rate can be ensured while achieving miniaturization of the pump unit.

[0193] In addition, the pump device M includes an electric motor 50 as a drive source for applying rotational driving force to the drive shaft 60.

[0194] Therefore, with the reduction of driving torque (driving load), the increase in power consumption of electric motor 50 can be suppressed, and electronic components with high rated current are not required, thus achieving miniaturization and cost reduction of the device.

[0195] Figures 14 to 21 The pump device M2 of the second embodiment of the present invention is indicated by the same symbols as the structure of the first embodiment and the description is omitted.

[0196] The pump device M2 in the second embodiment is an inline pump type electric pump device that delivers hydraulic oil as a fluid, including a housing body 110, a housing cover 120, a motor cover 30, an outer cover 40, an electric motor 50, a drive shaft 60, a pump unit 170 including an inner rotor 171 and an outer rotor 172, and a circuit board 80.

[0197] Here, the housing H2 of the pump unit M2 includes a housing body 110, a housing cover 120, and an outer cover 40.

[0198] The housing body 110 is formed of metal materials such as steel, cast iron, sintered steel, and aluminum alloy, and includes a cylindrical recess 111, a mating surface 12, a motor housing 13, a through hole 14 for the drive shaft 60 to pass through, a fitting recess 15, a flange 16, and four bosses 17.

[0199] The cylindrical recess 111 is a region that defines a portion of the receiving chamber Pc that rotatably houses the pump unit 170, such as Figures 14 to 16 As shown, it includes an inner circumferential surface 11a, opposing surfaces 111b perpendicular to the axis S, and two recesses 11c.

[0200] The opposing surface 111b is a plane that forms the bottom surface of the cylindrical recess 111 and is perpendicular to the axis S. It is the region that is adjacent to and faces the end faces 171a and 172a on the inner side (other side) of the pump unit 170 (inner rotor 171 and outer rotor 172) in the direction of the axis S. Furthermore, the term "adjacent and facing" also refers to the fluid lubrication region in the Stricker curve when there is an oil film of hydraulic oil as a fluid in between, for example, a state where the gap is formed of several μm to tens of μm.

[0201] like Figure 16 As shown, the opposing surface 111b is formed as a main opposing surface 111b1 adjacent to and facing the inner rotor 171, and a concave opposing surface 111b2 formed by being recessed further in the direction of the axis S than the main opposing surface 111b1.

[0202] Here, in Figure 16 In the diagram, the area enclosed by a circle with a double-dotted line centered on axis S represents the range of the inner opposing region Ai1 where the end face 171a of the inner rotor 171 and the main opposing surface 111b1 are adjacent to and facing each other in the direction of axis S.

[0203] In addition, Figure 16 In the diagram, the area enclosed by two circles centered on axis S2 and indicated by double-dotted lines represents the outer facing region Ao1 where the end face 172a of the outer rotor 172 and the facing surface 111b are adjacent to and facing each other in the direction of axis S. That is, the end face 172a of the outer rotor 172 is formed to be partially adjacent to and facing the main facing surface 111b1.

[0204] like Figure 16 As shown, the concave facing surface 111b2 is formed in a ring shape in the region near the outer periphery of the facing surface 111b, that is, in the region radially outward from the tooth row of the outer rotor 172 (the row of inner teeth 172d).

[0205] The housing cover 120 is joined to the housing body 110 in a manner that covers the cylindrical recess 111, and cooperates with the cylindrical recess 111 of the housing body 110 to define the receiving chamber Pc. It is formed into a flat plate shape using materials such as steel, cast iron, sintered steel, and aluminum alloy. Moreover, as Figure 14 , Figures 17 to 19 As shown, the housing cover 120 includes a cylindrical portion 21, a cylindrical portion 22, an opposing surface 123 perpendicular to the axis S, an intake port 24, an exhaust port 25, a central recess 26 for receiving the front end of the drive shaft 60, and three circular holes 27 through which a fastening screw b1 passes.

[0206] The opposing surface 123 is formed as a plane perpendicular to the axis S, and is the region adjacent to and facing the end faces 171b and 172b on the outer side (one side) of the pump unit 170 (inner rotor 171 and outer rotor 172) in the direction of the axis S. Furthermore, the term "adjacent and facing" similarly refers to the fluid-lubricated region in the Stribek curve, where a hydraulic oil film as a fluid exists as a barrier, for example, a gap of several μm to tens of μm.

[0207] like Figure 17 and Figure 19 As shown, the opposing surface 123 is formed as a main opposing surface 123a adjacent to and facing the inner rotor 171, and a concave opposing surface 123b that is recessed further in the direction of the axis S than the main opposing surface 123a.

[0208] Here, in Figure 19 In the diagram, the area enclosed by a circle with a double-dotted line centered on axis S represents the range of the inner opposing region Ai2, where the end face 171b of the inner rotor 171 and the main opposing surface 123a are adjacent to and facing each other in the direction of axis S.

[0209] In addition, Figure 19 In the diagram, the area enclosed by two circles centered on axis S2 and indicated by double-dotted lines represents the outer facing region Ao2 where the end face 172b of the outer rotor 172 and the facing surface 123 are adjacent to and facing each other in the direction of axis S. That is, the end face 172b of the outer rotor 172 is formed to be partially adjacent to and facing the main facing surface 123a.

[0210] like Figure 19 As shown, the concave facing surface 123b is formed in a ring shape in the region near the outer periphery of the facing surface 123, that is, in the region radially outward from the tooth row of the outer rotor 172 (the row of inner teeth 172d).

[0211] Pump unit 170 is disposed in housing Pc to apply a pumping action to the hydraulic oil, such as suction, pressurization, and ejection. Figure 14 , Figure 15 , Figure 17 , Figure 18 and Figure 20 As shown, this is a cycloidal pump that includes an inner rotor 171 and an outer rotor 172.

[0212] The inner rotor 171 is made of metal materials such as steel or sintered steel and is formed into an external gear with a tooth profile based on a cocycloid curve, including an end face 171a and an end face 171b perpendicular to the axis S, a fitting hole 171c for the drive shaft 60 to fit into, and external teeth 171d forming a tooth row on the outer periphery.

[0213] Furthermore, the inner rotor 171, centered on axis S, along... Figure 18 The arrow in the diagram rotates in the same direction as the drive shaft 60.

[0214] like Figure 19 As shown, end face 171a forms a plane perpendicular to axis S, and is configured to be adjacent to and facing the main opposing surface 111b1 of housing body 110 in the direction of axis S. End face 171b forms a plane perpendicular to axis S, and is configured to be adjacent to and facing the main opposing surface 123a of housing cover 120 in the direction of axis S. In addition, the width dimension W1 of inner rotor 171 in the direction of axis S is defined by end face 171a and end face 171b.

[0215] The outer rotor 172 is made of metal materials such as steel or sintered steel and is formed into an internal gear with teeth that can mesh with the inner rotor 171. It includes an end face 172a and an end face 172b perpendicular to the axis S, an outer peripheral face 172c that is radially adjacent to and facing the inner peripheral face 11a of the cylindrical recess 111, and an inner tooth 172d forming a tooth row on the inner circumference.

[0216] like Figure 19 As shown, end face 172a forms a plane perpendicular to axis S, and is configured to be adjacent to and facing the opposing surface 111b of housing body 110 in the direction of axis S. End face 172b forms a plane perpendicular to axis S, and is configured to be adjacent to and facing the opposing surface 123 of housing cover 120 in the direction of axis S. In addition, the width dimension W2 of outer rotor 172 in the direction of axis S is defined by end face 172a and end face 172b.

[0217] Here, the width dimension W2 of the outer rotor 172 is formed to be the same as the width dimension W1 of the inner rotor 171 (W2=W1).

[0218] Furthermore, the outer rotor 172 rotates in conjunction with the inner rotor 171, which rotates around axis S. The outer rotor 172 rotates at a slower speed than the inner rotor 171, centered on axis S2 which is offset from axis S, in the same direction as the inner rotor 171. Additionally, the partial meshing of the inner rotor 171 and outer rotor 172 continuously generates a pumping action of suction, pressurization, and ejection between them.

[0219] Regarding the relationship between the inner rotor 171 and outer rotor 172 forming the structure and the housing Pc (facing surfaces 111b and 123), as follows: Figure 21 As shown, in the direction of the axis S, the inner rotor 171 has a gap Ci1 defined between the end face 171a and the main opposing surface 111b1, and a gap Ci2 defined between the end face 171b and the main opposing surface 123a. That is, the inner rotor 171 and the housing Pc define a total gap Ci (=Ci1+Ci2) on both sides of the inner opposing region Ai1 and the inner opposing region Ai2.

[0220] Furthermore, in the S-axis direction, the outer rotor 172 has a gap Co1 defined between its end face 172a and the concave facing surface 111b2, and a gap Co2 defined between its end face 172b and the concave facing surface 123b. That is, the outer rotor 172 and the housing Pc define a total gap Co (=Co1+Co2) on both sides of the outer facing regions Ao1 and Ao2. Here, the gap ratio Co / Ci is set to 1.3 or higher.

[0221] That is, in the outer facing regions Ao1 and Ao2 of the outer rotor 172 and the facing surfaces 111b and 123 that are adjacent and facing each other in the direction of axis S, a gap enlargement region Ace is formed that includes the inner facing regions Ai1 and Ai2 of the inner rotor 171 and the facing surfaces 111b1 and 123 (main facing surfaces 111b1 and 123a) that are adjacent and facing each other in the direction of axis S.

[0222] Thus, by setting the gap expansion area Ace, the gap Co in the S direction of the outer rotor 172 is made larger than the gap Ci in the S direction of the inner rotor 171, which can especially reduce the driving torque (driving load) of the hydraulic oil at low temperatures.

[0223] Furthermore, in the second embodiment, the concave facing surfaces 111b2 and 123b are formed in an annular shape in the region that deviates radially outward from the tooth row of the outer rotor 172 (the row of inner teeth 172d), so that there is no change in the amount of hydraulic oil injected at high temperatures, and the driving torque of the hydraulic oil at low temperatures can be reduced.

[0224] As described above, in the pump device M2 according to the second embodiment of the present invention, the opposing surfaces 111b and 123 include the main opposing surfaces 111b1 and 123a adjacent to and facing each other of the inner rotor 171, and the concave opposing surfaces 111b2 and 123b formed by being recessed further in the direction of the axis S than the main opposing surfaces 111b1 and 123a. The gap enlargement region Ace is defined between the outer rotor 172 and the concave opposing surfaces 111b2 and 123b.

[0225] Therefore, by performing groove machining on the opposing surfaces 111b and 123 in the manner that the width dimensions W1 and W2 of the inner rotor 171 and the outer rotor 172 are the same as before (W1=W2), concave opposing surfaces 111b2 and 123b are formed, and the gap enlargement area Ace can be easily set.

[0226] In addition, in the pump assembly M2, the concave facing surfaces 111b2 and 123b are formed in a ring shape in the region that is radially outward from the tooth row of the outer rotor 172 (the row of inner teeth 172d).

[0227] Therefore, even at high temperatures, the amount of fluid (hydraulic oil) ejected will not change, so only the driving torque (driving load) can be reduced.

[0228] Furthermore, in the pump unit M2, the gap enlargement region Ace is formed on both sides facing the outer rotor 172 in the direction of the axis S, on one end side (facing surface 111b side) and the other end side (facing surface 123 side).

[0229] This allows for a significant reduction in driving torque (driving load).

[0230] In the embodiment described, an electric motor 50 is shown as the drive source for pump unit 70 and pump unit 170, but it is not limited to this. Even when using other drive sources, the drive torque at low temperatures can be reduced.

[0231] In the described embodiment, housings H and H2 are shown as housings, which include: housing body 10 and housing body 110, including cylindrical recesses 11 and 111 that define opposing surfaces 11b and 111b; and housing cover 20 and housing cover 120, which engage with housing body 10 and housing body 110 to define receiving chamber Pc and define opposing surfaces 23 and 123, but are not limited thereto. The gap enlargement region of the present invention may also be used in the structure of housings that represent other segmented structures or forms.

[0232] In the embodiment described above, concave facing surfaces are shown as annular concave facing surfaces 111b2 and 123b in a region that deviates radially outward from the tooth row (the row of internal teeth 172d) of the outer rotor 172. However, this is not a limitation, and the concave facing surfaces may be formed to a range that extends further radially inward.

[0233] In the described embodiment, a paracycloid pump with a tooth profile based on a paracycloid curve is shown as a pump unit, but it is not limited to this. As long as it includes an inner rotor and an outer rotor, pump units with other configurations can also be used.

[0234] As described above, when the pump device of the present invention draws in and ejects fluid at low temperatures, it can suppress and reduce the increase in driving torque caused by the viscous resistance of the fluid while suppressing changes in the amount of fluid ejected. Furthermore, it can suppress the increase in power consumption when using an electric motor as the drive source. A pump device that does not require electronic components with high rated current can be obtained. Therefore, it can of course be applied to the cooling and lubrication system of vehicle transmission devices, the cooling and lubrication system of engine, and is also useful for other devices that require the circulation of hydraulic oil.

Claims

1. A pump device, characterized in that, include: The drive shaft is centered on a specified axis. An inner rotor connected to the drive shaft and an outer rotor that rotates in conjunction with the inner rotor to apply a pumping action to the fluid; as well as The housing includes a fluid intake port, an exhaust port, and a receiving chamber that houses the inner and outer rotors and defines opposing surfaces perpendicular to the axis in an adjacent and opposing manner. The pump assembly includes an inner facing region where the inner rotor and the facing surface are adjacent and facing each other in the axial direction, and an outer facing region where the outer rotor and the facing surface are adjacent and facing each other in the axial direction. The outer facing regions include a gap expansion region where the gap is larger than that of the inner facing regions.

2. The pump device according to claim 1, characterized in that, The widened gap region is defined between the outer rotor, which is formed to be narrower than the inner rotor, and the opposing surface in the axial direction.

3. The pump device according to claim 2, characterized in that, The gap enlargement region is formed on both sides facing the outer rotor in the axial direction, at one end and the other end.

4. The pump device according to claim 1, characterized in that, The opposing surfaces include the main opposing surfaces adjacent to and facing each other of the inner rotor, and a concave opposing surface formed by being recessed further in the axial direction than the main opposing surfaces. The gap enlargement region is defined between the outer rotor and the concave facing surface.

5. The pump device according to claim 4, characterized in that, The concave facing surface is formed in a ring shape in the region radially outward from the tooth row of the outer rotor.

6. The pump device according to claim 4, characterized in that, The gap enlargement region is formed on both sides facing the outer rotor in the axial direction, at one end and the other end.

7. The pump device according to claim 1, characterized in that, When the total gap between the two sides of the inner opposing regions is set as Ci, and the total gap between the two sides of the outer opposing regions is set as Co, The gap ratio Co / Ci is greater than 1.

3.

8. The pump device according to any one of claims 1 to 7, characterized in that, The inhalation port and the ejection port are formed as opposing surfaces facing one side of the containment chamber.

9. The pump device according to claim 8, characterized in that, On the opposite side of the containment chamber, a recess is formed in the axial direction to temporarily store fluid.

10. The pump device according to claim 8, characterized in that, The housing comprises: a housing body including a cylindrical recess that rotatably accommodates the outer rotor and the inner rotor and defines the opposing surfaces; and a housing cover that engages with the housing body to define the receiving chamber and the opposing surfaces. The housing includes: the suction port, an intake port formed adjacent to the suction port and for drawing fluid from the outside, the ejection port, and an outlet port formed adjacent to the ejection port and for ejecting fluid from the outside.

11. The pump device according to any one of claims 1 to 7, characterized in that, The inner rotor and the outer rotor are cycloidal pumps with tooth profiles based on a cycloidal curve.

12. The pump device according to any one of claims 1 to 7, characterized in that, It includes an electric motor that applies rotational driving force to the drive shaft.

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