Liquid pump device

Abstract

To provide a liquid pump device which enables a temperature sensor to be easily assembled thereto without increasing the size of the device and can detect a temperature of a working fluid with high accuracy.SOLUTION: A liquid pump device suctions and discharges a liquid and includes: a pump unit 50 which rotates so as to cause the liquid to flow; a housing H which houses the pump unit and defines a liquid passage 14; and a temperature sensor 80 which is disposed with a tip area 80a protruding into the liquid passage 14 so as to measure a temperature of the liquid flowing in the passage 14.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a liquid pump device that sucks and discharges a liquid, and particularly to a liquid pump device provided with a temperature sensor for detecting the temperature of a liquid such as hydraulic oil.

Background Art

[0002] As a conventional liquid pump device, there is known an electric pump including a housing that houses a circuit board and a motor, a temperature sensor mounted on the circuit board disposed in the housing for detecting the temperature of hydraulic oil, a port block disposed adjacent to the outside of the housing, a trochoid pump disposed between the port block and the housing for flowing the hydraulic oil, a heat dissipation member disposed between the inner wall of the housing and the circuit board, and a heat transfer member provided on the circuit board (for example, Patent Document 1). In this electric pump, the temperature sensor is configured to detect the temperature of the hydraulic oil via the heat transfer member, the heat dissipation member, and the housing.

[0003] In the arrangement structure of the temperature sensor as described above, since the heat of the hydraulic oil is dissipated to intervening members such as the housing and the heat dissipation member in the middle of the path through which the heat is transmitted to the temperature sensor, the temperature of the hydraulic oil cannot be detected with high accuracy. Further, when a temperature sensor is mounted on the liquid pump device, it is required to be easily assembled without causing an increase in size. Furthermore, a liquid such as hydraulic oil has different heat transfer characteristics from a gas such as air with low viscosity and mass, and when the temperature is low, the flow may easily become stagnant. Therefore, it is necessary to consider the behavior of the liquid when measuring the temperature of the liquid.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

[0005] The present invention has been made in view of the above circumstances, and its purpose is to provide a liquid pump device that, in view of the problems of the prior art described above, allows for easy assembly of a temperature sensor without increasing the size of the device, and can detect the temperature of the hydraulic fluid with high accuracy. [Means for solving the problem]

[0006] The liquid pump device of the present invention comprises a pump unit that rotates to cause a liquid to flow, a housing that houses the pump unit and defines a passage for the liquid, and a device for measuring the temperature of the liquid flowing through the passage. Includes a bottomed cylindrical member inserted into the passageway. A temperature sensor and The cylindrical member is made of a resin material and includes a small diameter portion that houses a sensor element and is positioned with a gap between it and the inner wall surface of the passage at its tip, and a surrounding wall portion that partially surrounds the small diameter portion by cutting out a region facing the upstream side of the passage in order to restrict liquid flowing from the upstream side of the passage, passing around the small diameter portion, and to the downstream side of the passage from colliding with the inner wall surface around the small diameter portion. It is structured as follows.

[0011] In the above-described liquid pump device, the surrounding wall portion may be configured to have an outer wall surface that faces the inner wall surface of the first straight passage.

[0012] In the above-described liquid pump device, the surrounding wall portion may be configured to have a plurality of protruding portions that extend from the outer wall surface and abut against the inner wall surface of the first straight passage, in order to define a gap between the inner wall surface and the outer wall surface of the first straight passage.

[0013] Furthermore, the liquid pump device of the present invention includes a pump unit that rotates to cause a liquid to flow, a housing that houses the pump unit and defines a passage for the liquid, and A circuit board on which a motor having a drive shaft that rotates around a predetermined axis to rotate the pump unit, and a control unit that controls the motor's operation are mounted. The device includes a temperature sensor connected to a circuit board for measuring the temperature of the liquid flowing through the passage, with its tip protruding into the passage. The housing comprises a housing body defining a joint surface to be joined to the object to be applied, a pump housing recess for housing the pump unit, a motor housing recess for housing the motor, a through-passage extending parallel to the axis to form part of the passage and opening into the joint surface, and a connecting passage extending inclined with respect to the axis to form part of the passage and connecting the pump housing recess to the through-passage. The housing also includes a pump cover joined to the housing body to cover the pump housing recess and defining an opening for the liquid to pass through. The temperature sensor is positioned so that its tip faces the intersection of the through-passage and the connecting passage.

[0017] In the above liquid pump device, the housing includes a motor cover that is joined to the housing body to cover the motor housing recess. The temperature sensor includes a bottomed cylindrical member provided in the motor cover and inserted into a through-passage, and a sensor element electrically connected to a circuit board and positioned in the tip region inside the cylindrical member. You may adopt this configuration.

[0019] In the above-described liquid pump device, the cylindrical member may include a large-diameter portion that fits into the inner wall surface of the through passage, and a small-diameter portion that has a bottomed shape at the tip of the large-diameter portion and is positioned with a gap between it and the inner wall surface of the through passage, and which also houses a sensor element, with the small-diameter portion positioned in the intersection region of the through passage and the communication passage.

[0020] In the above-described liquid pump device, the cylindrical member may be made of a resin material and may include a surrounding wall portion that is curved so as to partially surround the small-diameter portion by cutting out the region facing the communication passage.

[0021] In the above-described liquid pump device, the surrounding wall portion may be configured to have an outer wall surface that faces the inner wall surface of the through passage.

[0022] In the above-described liquid pump device, the surrounding wall portion may be configured to have a plurality of protruding portions that extend from the outer wall surface and abut against the inner wall surface of the passage, in order to define a gap between the inner wall surface and the outer wall surface of the passage.

[0023] In the above-described liquid pump device, the housing may include an outer cover that is joined to the motor cover to cover a circuit board located outside the motor cover.

[0024] In the above-described liquid pump device, the passage where the temperature sensor is located may be configured to be a discharge passage through which pressurized liquid is discharged by the pump unit.

[0025] In the above-described liquid pump device, a configuration may be adopted that includes a filter member positioned upstream of the suction port into which the liquid is drawn into the pump unit.

[0026] In the above-described liquid pump device, the pump unit may be a trochoidal type pump unit including an inner rotor and an outer rotor. [Effects of the Invention]

[0027] According to the liquid pump device having the above configuration, the temperature sensor can be easily assembled without causing an increase in the size of the device, and the temperature of the hydraulic oil can be detected with high accuracy.

Brief Description of the Drawings

[0028] [Figure 1] It is an external perspective view showing the liquid pump device according to the first embodiment of the present invention. [Figure 2] It is an exploded perspective view of the liquid pump device according to the first embodiment, viewed from the pump cover side. [Figure 3] It is an exploded perspective view of the liquid pump device according to the first embodiment, viewed from the outer cover side. [Figure 4] It is a cross-sectional view of the liquid pump device according to the first embodiment. [Figure 5] It is a perspective view showing the housing body of the liquid pump device according to the first embodiment. [Figure 6] It is a perspective view showing the housing body of the liquid pump device according to the first embodiment. [Figure 7] It is a cross-sectional view showing the housing body of the liquid pump device according to the first embodiment. [Figure 8] It is a perspective view showing the motor cover and the temperature sensor of the liquid pump device according to the first embodiment. [Figure 9] It is a partial cross-sectional view showing the motor cover and the temperature sensor of the liquid pump device according to the first embodiment. [Figure 10] It is a schematic diagram showing the relationship between the temperature sensor disposed in the passage and the flow of the hydraulic oil in the liquid pump device according to the first embodiment. [Figure 11] It is a cross-sectional view showing the state in which the liquid pump device according to the first embodiment is joined and attached to the application object. [Figure 12] It is a graph showing the detection characteristics of the temperature sensor in the liquid pump device of the present invention. [Figure 13] It is a cross-sectional view showing the motor cover and the temperature sensor of the liquid pump device according to the second embodiment. [Figure 14]This is a cross-sectional view showing the motor cover and temperature sensor of a liquid pump device according to the third embodiment. [Figure 15] This is a perspective view showing the temperature sensor of the liquid pump device according to the third embodiment. [Figure 16] This shows a temperature sensor of a liquid pump device according to the third embodiment, and is a perspective cross-sectional view taken from a plane including its center line. [Figure 17] This is a cross-sectional view of a liquid pump device according to the third embodiment. [Figure 18] This is a schematic diagram showing the relationship between a temperature sensor placed in a passage and the flow of hydraulic fluid in a liquid pump device according to the third embodiment. [Modes for carrying out the invention]

[0029] Embodiments of the present invention will be described below with reference to the accompanying drawings. The liquid pump device M according to the first embodiment is an electric pump device that targets hydraulic oil as the liquid, and as shown in Figures 1 to 3, it comprises a housing body 10, a pump cover 20, a motor cover 30, an outer cover 40, a pump unit 50, a motor 60, a circuit board 70, a temperature sensor 80, and a filter member 90. Here, the housing H of the liquid pump device M is composed of the housing body 10, the pump cover 20, the motor cover 30, and the outer cover 40.

[0030] Furthermore, the object 1 to which the liquid pump device M is applied includes a joint surface 1a, a hydraulic fluid introduction passage 1b, a hydraulic fluid outlet passage 1c, a fitting recess 1d, and screw holes (not shown), as shown in Figure 11. The object 1 is, for example, a cooling and lubrication system for a vehicle's transmission, an engine cooling and lubrication system, or other devices that require the circulation of hydraulic fluid.

[0031] The housing body 10 is formed from a metal material such as steel, cast iron, sintered steel, or aluminum alloy, and as shown in Figures 2, 3, 5 to 7, it includes a flange portion 11, a pump housing recess 12, a motor housing recess 13, a discharge passage 14 for passing liquid, a through hole 15 centered on the axis S, a fitting recess 16, and a joint surface 17.

[0032] The flange portion 11 includes a joining surface 11a that is joined to the object to be applied 1, an annular groove 11b formed on the joining surface 11a, an annular end surface 11c, an outer peripheral wall 11d for attaching the filter member 90, and four holes 11e through which mounting screws for attaching to the object to be applied 1 pass. The joining surface 11a is formed as a plane perpendicular to the axis S so as to be joined to the joining surface 1a of the object to be applied 1. The annular groove 11b is formed to receive a rubber sealing member SR1 interposed between the joining surface 11a and the joining surface 1a of the object to be applied 1. The annular end face 11c is formed as a plane perpendicular to the axis S in order to join the pump cover 20 that covers the pump housing recess 12, and is provided with three screw holes 11c1 into which screws b1 that fasten the pump cover 20 are screwed. The outer peripheral wall 11d is formed in a position that protrudes from the joint surface 11a in the axial direction S in order to attach the filter member 90 by snap-fit, and is provided with a locking groove on its radial outer peripheral surface.

[0033] The pump housing recess 12 is an area that rotatably houses the pump unit 50 and includes an inner circumferential surface 12a, a bottom surface 12b, and an outlet 12c formed recessed in the bottom surface 12b. The inner circumferential surface 12a forms a cylindrical surface centered on an axis that is offset parallel to the axis S, and slidably supports the outer circumferential surface of the outer rotor 52, which forms part of the pump unit 50. The bottom surface 12b is in slidable contact with the inner end surface of the pump unit 50 in the axial direction S. Outlet 12c is the region where the hydraulic fluid pressurized by the pump unit 50 flows out toward the discharge passage 14.

[0034] The motor housing recess 13 is an area for housing the motor 60 and includes inner circumferential surfaces 13a, 13b, and 13c. The inner circumferential surface 13a is formed as a cylindrical surface centered on the axis S in order to fit and fix the stator 61 of the motor 60. The inner circumferential surface 13b is formed as a cylindrical surface centered on the axis S, in order to fit and fix the bearing B1 that rotatably supports the drive shaft 63 of the motor 60. The inner circumferential surface 13c is formed as a cylindrical surface centered on the axis S in order to fit and fix the lip-type sealing member Sr.

[0035] The discharge passage 14 is a passage that guides the hydraulic fluid pressurized by the pump unit 50 from the pump chamber to the discharge port 14a1, and as shown in Figure 7, it comprises a through passage 14a as a first straight passage and a connecting passage 14b as a second straight passage. The through passage 14a extends parallel to the axis S from the joint surface 17 of the housing body 10, penetrates the housing body 10, and is formed as a straight passage defining a discharge port 14a1 that opens to the joint surface 11a of the flange portion 11. The connecting passage 14b extends at an angle θ with respect to the axis S and is formed as a straight passage intersecting the through passage 14a in order to connect the outlet 12c of the pump chamber of the pump housing recess 12 to the middle of the through passage 14a.

[0036] Here, the intersection angle θ of the connecting passage 14b with respect to the through passage 14a is set to an angle that allows a tool DT, such as a drill, to be inserted through the opening of the pump housing recess 12 to perform hole drilling. Thus, since the through passage 14a and connecting passage 14b, which serve as the discharge passage 14, are formed as straight passages, they can be easily processed by drilling or the like. In particular, because the connecting passage 14b is inclined at the angle θ with respect to the axis S, the connecting passage 14b can be easily processed without affecting the shape of the pump housing recess 12.

[0037] The insertion hole 15 is formed in the wall portion 15a separating the pump housing recess 12 and the motor housing recess 13 as a cylindrical hole centered on the axis S, in order to allow the drive shaft 63 to pass through without contact. The fitting recess 16 defines a cylindrical surface centered on the axis S in the outer end region of the motor housing recess 13. The fitting projection 32 of the motor cover 30 is then fitted into the fitting recess 16. In other words, by fitting the fitting projection 32 of the motor cover 30 into the fitting recess 16 of the housing body 10, the center of the bearing cylindrical portion 33 formed on the motor cover 30 is positioned coaxially with the axis S of the housing body 10. The joining surface 17 is formed as a plane perpendicular to the axis S in order to join the motor cover 30 that covers the motor housing recess 13, and is equipped with five screw holes 17a for screwing in screws that fasten the motor cover 30, and positioning projections 17b for positioning the motor cover 30 around the axis S.

[0038] The pump cover 20 is joined to the housing body 10 and fixed by screws b1 to cover the pump housing recess 12 of the housing body 10, and is formed in a flat plate shape using a material such as steel, cast iron, sintered steel, or aluminum alloy. As shown in Figures 2 and 3, the pump cover 20 is equipped with an inlet 21 as an opening for hydraulic fluid to pass through, an inner wall surface 22, and three circular holes 23 through which the screw b1 passes. The intake port 21 is shaped like a crescent moon in order to guide the hydraulic fluid into the pump chamber of the pump unit 50. The inner wall surface 22 slidably receives the outer end surface of the pump unit 50 housed in the pump housing recess 12.

[0039] The motor cover 30 is joined to the housing body 10 to cover the motor housing recess 13 of the housing body 10 and is fixed with screws b3, and is made of resin material. As shown in Figures 2, 3, 8, and 9, the motor cover 30 includes a joining surface 31, a fitting projection 32, a bearing cylindrical portion 33, an opening 34, a fitting hole 35, four boss portions 36, a connector portion 37 with embedded terminals, a joining surface 38 for joining the outer cover 40, five circular holes 39a for passing screws b3, two screw holes 39b for screwing in screws b4, and a fitting hole 39c for fitting the positioning projection 17b.

[0040] The joining surface 31 is joined to the joining surface 17 of the housing body 10. The fitting projection 32 is fitted into the fitting recess 16 of the housing body 10, positioning the center of the bearing cylindrical portion 33 on the axis S. The bearing cylindrical portion 33 is formed by press-fitting a metal molded product that defines a cylindrical surface centered on the axis S, in order to fit and fix the bearing B2 that supports the drive shaft 63 of the motor 60. As shown in Figure 4, the opening 34 is formed as a circular hole that opens coaxially with the bearing cylindrical portion 33 in order to face the detected portion D provided at the end of the drive shaft 63 toward the detection sensor 72 provided on the circuit board 70. The fitting hole 35 is formed to open in the axial direction S in order to fit and fix the cylindrical member 81 which forms part of the temperature sensor 80. The boss portion 36 is provided with a screw hole into which a screw b2 fastens the circuit board 70, which is located on the outside of the motor cover 30, is screwed in.

[0041] The outer cover 40 covers the circuit board 70 which is located outside the motor cover 30. It is made of resin material and, as shown in Figures 2 and 3, has a housing portion 41 for housing the circuit board 70, a flange portion 42 which is joined to the joint surface 38 of the motor cover 30, and seven circular holes 43 formed in the flange portion 42 through which fastening screws b3 and b4 pass. Then, with the circuit board 70 attached to the motor cover 30, the outer cover 40 is joined to the joint surface 38 of the motor cover 30 by joining the flange portion 42 to the joint surface 38 of the motor cover 30, and is joined to the housing body 10 by five screws b3 sandwiching the motor cover 30, and is also joined to the motor cover 30 by two screws b4.

[0042] The pump unit 50 is positioned in the pump housing recess 12 to exert a pumping action on the hydraulic fluid, including suction, pressurization, and discharge, and is a trochoidal pump unit including an inner rotor 51 and an outer rotor 52.

[0043] The inner rotor 51 is formed as an external gear with a trochoidal tooth profile using a metal material such as steel or sintered steel, and as shown in Figures 2 and 3, it has an end face that slides against the bottom surface 12b of the housing body 10, an end face that slides against the inner wall surface 22 of the pump cover 20, a fitting hole 51a for fitting the drive shaft 63, and a tooth row (seven protrusions and seven recesses) on its outer circumference. The inner rotor 51 then rotates integrally with the drive shaft 63 in one direction around the axis S.

[0044] The outer rotor 52 is formed as an internal gear with a tooth profile that can mesh with the inner rotor 51, using a metal material such as steel or sintered steel. As shown in Figures 2 and 3, it has an end face that slides against the bottom surface 12b of the housing body 10, an end face that slides against the inner wall surface 22 of the pump cover 20, a cylindrical outer surface that slidably contacts the inner circumferential surface 12a, and a tooth row (eight convex portions and eight concave portions) on its inner circumference.

[0045] The outer rotor 52 rotates in conjunction with the rotation of the inner rotor 51, which rotates around axis S, but at a slower speed than the inner rotor 51, and around an axis offset from axis S, in the same direction as the inner rotor 51. Furthermore, the partial meshing of the inner rotor 51 and the outer rotor 52 creates a continuous pumping action between them, involving suction, pressurization, and discharge.

[0046] Motor 60 is a three-phase brushless motor equipped with a stator 61, rotor 62, and drive shaft 63. The stator 61 comprises a stator core formed from a steel plate made of a magnetic material, a bobbin formed from an electrically insulating resin material, and a coil wound around the bobbin. The rotor 62 comprises a rotor core formed from a steel plate made of magnetic material, and permanent magnets embedded in the rotor core. The drive shaft 63 is formed in a cylindrical shape extending in the axial direction S using a steel material or the like, and is fitted to the rotor 62 so as to rotate integrally with the rotor 62.

[0047] The drive shaft 63 is supported on both sides of the rotor 62, with one side supported by a bearing B1 provided on the housing body 10 and the other side supported by a bearing B2 provided on the motor cover 30, so as to be able to rotate around the axis S. Furthermore, the drive shaft 63 has a fitting hole in the inner rotor 51 in the area closer to the tip than the bearing B1. 51a It is fitted into and transmits rotational driving force to the pump unit 50. Furthermore, a lip-type sealing member Sr is positioned on the drive shaft 63 in the outer peripheral region between the bearing B1 and the insertion hole 15, sealing the area to prevent hydraulic fluid from flowing from the pump housing recess 12 towards the motor housing recess 13.

[0048] As shown in Figures 3, 4, and 11, the circuit board 70 is formed in a flat shape and is fixed to the motor cover 30 by screws b2. The circuit board 70 has wiring printed on it, and a control unit 71 for controlling the drive of the motor 60 and various electronic components (not shown) are mounted on it. In addition, a detection sensor 72 is mounted on the inner surface of the motor cover 30 facing the opening 34. The detection sensor 72 detects the rotational position of the rotor 62 and is equipped with three Hall elements arranged in an arc shape around the axis S so as to face the part to be detected D in the direction of the axis S. Furthermore, a sensor element 82, which constitutes part of the temperature sensor 80, is electrically connected to the circuit board 70.

[0049] The temperature sensor 80 measures the temperature of the hydraulic fluid flowing through the discharge passage 14, which serves as a liquid passage, and comprises a bottomed cylindrical member 81 and a sensor element 82 positioned in the tip region inside the cylindrical member 81. The cylindrical member 81 is made of resin material and, as shown in Figures 8 and 9, is formed such that its center line C extends parallel to the axis S when assembled, and is equipped with a fitting portion 81a, a large diameter portion 81b, a small diameter portion 81c, and an annular groove 81d.

[0050] The mating portion 81a is formed to fit into the mating hole 35 of the motor cover 30. The large-diameter portion 81b is formed to fit snugly against the inner wall surface of the through passage 14a when inserted into the through passage 14a of the housing body 10. The small-diameter portion 81c is located in the tip region 80a of the cylindrical member 81, and is bottomed out towards the tip side of the large-diameter portion 81b, housing the sensor element 82 inside, and is formed to be positioned with a gap between it and the inner wall surface of the through passage 14a when inserted into the through passage 14a of the housing body 10. The annular groove 81d is formed near the tip of the large-diameter portion 81b in order to fit the O-ring SR2, which is in close contact with the inner wall surface of the through passage 14a.

[0051] The sensor element 82 is a thermistor and is positioned inside the small-diameter portion 81c of the cylindrical member 81, that is, in the tip region 80a of the cylindrical member 81. A lead wire 82a passes through the inside of the cylindrical member 81 and is electrically connected to the circuit wiring on the circuit board 70. The internal space of the cylindrical member 81 is filled and sealed with a resin material R after the sensor element 82 is inserted.

[0052] The temperature sensor 80 is pre-assembled into the motor cover 30, and with the circuit board 70 attached to the motor cover 30, the lead wires 82a of the sensor element 82 are connected to the circuit wiring on the circuit board 70, so that the motor cover 30 and the circuit board 70 can be handled as a single unit. As a result, when assembling the motor cover 30 to the housing body 10, the temperature sensor 80 is inserted into the through passage 14a, making assembly easier.

[0053] In its assembled state, the temperature sensor 80 is positioned such that its tip region 80a faces the intersection region Ca of the through passage (first straight passage) 14a and the connecting passage (second straight passage) 14b, as shown in Figures 7 and 10. As a result, the hydraulic fluid flowing through the connecting passage 14b collides with the tip region 80a, then changes direction and flows through the through passage 14a before being discharged from the discharge port 14a1. In other words, the temperature sensor 80 is positioned to protrude into the discharge passage 14 in order to measure the temperature of the hydraulic fluid. Therefore, the temperature sensor 80 can directly detect the temperature of the hydraulic fluid flowing through the discharge passage 14 without heat being absorbed by intervening materials, as in conventional systems.

[0054] In particular, the tip region 80a of the temperature sensor 80 not only protrudes into the discharge passage 14, but is also positioned in the intersection region Ca where the direction changes from the connecting passage 14b to the through passage 14a, as shown in Figure 10. As a result, the hydraulic fluid flows downstream after colliding with the tip region 80a without stagnating. This makes it possible to detect the temperature of the flowing hydraulic fluid, rather than stagnant hydraulic fluid, with high accuracy. Furthermore, the tip region 80a of the temperature sensor 80 is formed as a small-diameter portion 81c, and a gap is formed between it and the inner wall surface of the through passage 14a. As a result, the outer wall surface of the tip region 80a is reliably exposed to the hydraulic fluid, and the temperature of the hydraulic fluid can be detected with higher accuracy.

[0055] The filter member 90 prevents impurities such as dirt mixed in the hydraulic fluid supplied from the upstream side of the object to be applied 1 from entering the pump unit 50. As shown in Figure 1, it comprises a mesh portion 91 that allows only hydraulic fluid to pass through and a frame portion 92 that holds the mesh portion 91. Furthermore, as shown in Figure 11, the filter member 90 is formed to fit into a fitting recess 1d that opens on the joint surface 1a of the object to be applied 1 when the liquid pump device M is attached to the object to be applied 1. The frame portion 92 is provided with a locking portion 92a, as shown in Figures 2 and 3. The filter member 90 is then assembled to the housing body 10 by the locking portion 92a being snap-fitted to the outer peripheral wall 11d of the housing body 10.

[0056] In this way, the filter member 90 prevents impurities from flowing into the pump unit 50, preventing malfunctions due to impurities getting stuck in the pump unit 50 or the accumulation of impurities in the discharge passage 14 through which the hydraulic fluid flows. As a result, the tip region 80a of the temperature sensor 80 is always exposed to the hydraulic fluid without being covered by impurities, enabling high-precision detection of the hydraulic fluid temperature.

[0057] Next, the assembly procedure for the liquid pump device M according to the first embodiment will be described. Prior to assembly, the housing body 10, pump cover 20, motor cover 30, outer cover 40, pump unit 50 (inner rotor 51, outer rotor 52), motor 60 (stator 61, rotor 62, drive shaft 63), control unit 71, circuit board 70 on which various electronic components are mounted, filter member 90, bearings B1, B2, corrugated spring Sb as a thrust bearing, lip-type seal member Sr, and multiple screws b1, b2, b3, b4 are prepared.

[0058] Prior to the sub-assembly process, the drive shaft 63 is fitted and fixed to the rotor 62, and bearings B1, B2 and the detection unit D are assembled to the drive shaft 63. Furthermore, a sensor element 82 is inserted into the cylindrical member 81 and sealed in a resin material R to form a temperature sensor 80. Subsequently, the temperature sensor 80 is fixed to the motor cover 30 by fitting the fitting portion 81a into the fitting hole 35. The circuit board 70 is then fixed to the boss portion 36 of the motor cover 30 using screws b2, and the lead wires 82a of the sensor element 82 are connected to the circuit wiring on the circuit board 70.

[0059] In the main assembly process, first, the motor 60 is incorporated into the motor housing recess 13 of the housing body 10. Specifically, the lip-type sealing member Sr is fitted onto the inner circumferential surface 13c, and the stator 61 is fitted onto the inner circumferential surface 13a and fixed in place. Next, the drive shaft 63, to which the rotor 62 is fitted and fixed, is inserted with the corrugated spring Sb sandwiched between the bearing B1 and the lip-type sealing member Sr. The bearing B1, attached to one side of the drive shaft 63, is fitted and fixed to the inner circumferential surface 13b, and the tip region of the drive shaft 63 is made to protrude into the pump housing recess 12 through the insertion hole 15.

[0060] Next, the motor cover 30, to which the circuit board 70 is attached, is brought closer to the housing body 10 from the axial direction S so as to cover the motor housing recess 13. Then, the bearing B2 attached to the other side of the drive shaft 63 is fitted into the bearing cylindrical portion 33, the cylindrical member 81 of the temperature sensor 80 with the O-ring SR2 fitted is inserted into the through passage 14a, the positioning projection 17b is inserted into the fitting hole 39c, the fitting projection 32 is fitted into the fitting recess 16, and the joining surface 31 is joined to the joining surface 17 of the housing body 10 with a liquid sealant interposed therebetween. The terminals and wiring extending from the stator 61 are appropriately guided to the outside of the motor cover 30 and connected to the circuit wiring on the circuit board 70. As a result, the drive shaft 63 of the motor 60 is supported by the housing body 10 and the motor cover 30 so as to be rotatable around the axis S via bearings B1 and B2.

[0061] Next, the outer cover 40 is brought closer to the motor cover 30 so as to cover the circuit board 70 from the axial direction S, and the flange portion 42 is joined to the joint surface 38 of the motor cover 30 with a liquid sealant interposed between them. Then, five screws b3 are screwed into the screw holes 17a of the housing body 10 through the circular holes 43 and 39a, and two screws b4 are screwed into the screw holes 39b of the motor cover 30 through the circular hole 43. As a result, the outer cover 40 is fastened and secured to the housing body 10 with the motor cover 30 in between, and is also fastened and secured to the motor cover 30.

[0062] Next, the inner rotor 51 is inserted into the pump housing recess 12 of the housing body 10 and fitted to the drive shaft 63 so as to rotate integrally with it. Next, the outer rotor 52 is inserted into the pump housing recess 12 so as to mesh with the inner rotor 51.

[0063] Next, the pump cover 20 is brought closer from the axial direction S so as to cover the pump housing recess 12, and is joined to the annular end face 11c of the housing body 10, and fastened and fixed to the housing body 10 by screws b1. Subsequently, the filter member 90 is brought closer to the housing body 10 from the axial direction S so as to cover the pump cover 20, and the locking portion 92a is snap-fitted and fixed to the outer peripheral wall 11d. With the above steps, the assembly of the liquid pump device M is complete. Note that the assembly procedure is not limited to the above, and other procedures may be used.

[0064] Next, when attaching the liquid pump device M to the object 1, prepare the liquid pump device M and the sealing member SR1. Then, the sealing member SR1 is fitted into the annular groove 11b of the joining surface 11a, and as shown in Figure 11, the filter member 90 is fitted into the fitting recess 1d of the object to be applied 1, and the joining surface 11a is joined to the joining surface 1a of the object to be applied 1. Then, the screw is passed through the hole 11e in the housing body 10 and screwed into the screw hole of the object to be applied 1. This completes the assembly of the liquid pump device M to the object to be applied 1. In this state, the introduction passage 1b of the object to be applied 1 communicates with the inlet 21 of the liquid pump device M through the filter member 90, and the discharge port 14a1 of the liquid pump device M communicates with the outlet passage 1c of the object to be applied 1.

[0065] Next, the pump operation of the liquid pump device M described above will be explained. The control unit 71 drives the motor 60, causing the drive shaft 63 and inner rotor 51 to rotate. When the outer rotor 52 rotates in the same direction as the inner rotor 51, the hydraulic fluid supplied through the introduction passage 1b is drawn into the pump chamber through the suction port 21 and pressurized in the pump chamber. Next, the pressurized hydraulic fluid flows through the discharge passage 14, that is, the connecting passage 14b, to the intersection region Ca, changes direction while colliding with the tip region 80a of the temperature sensor 80, flows through the through passage 14a, is discharged from the discharge port 14a1, and is sent to the outlet passage 1c of the object to be applied 1.

[0066] In the above configuration, the temperature sensor 80 is positioned protruding into the discharge passage 14, so it can directly detect the temperature of the flowing hydraulic fluid. Here, we simulated the difference in detection accuracy when the amount of protrusion of the tip region 80a of the temperature sensor 80 into the hydraulic fluid passage was changed. As a result, as shown in Figure 12, the detection accuracy improved as the amount of protrusion of the temperature sensor 80 into the passage increased. In other words, in configurations where the tip region 80a of the temperature sensor does not protrude into the passage but is simply exposed to the hydraulic fluid, the detection accuracy was low, and the detection accuracy improved as the amount of protrusion of the tip region 80a of the temperature sensor increased. In particular, in this embodiment, since the tip region 80a of the temperature sensor 80 is positioned to face the intersection region Ca of the through passage 14a and the communication passage 14b, the temperature of the hydraulic fluid can be detected with high accuracy.

[0067] As described above, in the liquid pump device M according to the first embodiment, the tip region 80a of the temperature sensor 80 is positioned to protrude into the hydraulic fluid passage (discharge passage 14), so that the temperature of the hydraulic fluid can be directly detected without heat being absorbed by intervening objects as in the conventional method. Furthermore, the temperature sensor 80 is positioned so that the hydraulic fluid flowing through the passage (discharge passage 14) collides with its tip region 80a. Specifically, the tip region 80a is positioned to face the intersection region Ca of the through passage 14a and the connecting passage 14b. Therefore, it is possible to detect the temperature of the flowing hydraulic fluid with high accuracy, rather than the temperature of stagnant hydraulic fluid. In particular, the tip region 80a of the temperature sensor 80 is formed to include a large-diameter portion 81b that fits snugly against the inner wall surface of the through passage 14a, and a small-diameter portion 81c that is positioned with a gap between it and the inner wall surface of the through passage 14a and houses the sensor element 82. Therefore, around the small-diameter portion 81c actively The hydraulic fluid can be guided through it. In other words, by actively exposing the small-diameter portion 81c, which houses the sensor element 82, to the hydraulic fluid, the heat of the hydraulic fluid can be efficiently sensed. Therefore, the temperature of the hydraulic fluid can be detected with high accuracy.

[0068] Furthermore, according to the liquid pump device M of the first embodiment, the temperature sensor 80 is integrally incorporated with the circuit board 70, and the temperature sensor 80 can be inserted and positioned in the passage (through passage 14a) simply by assembling the motor cover 30 to which the circuit board 70 is attached to the housing body 10. Compared to a configuration in which the components are assembled separately, the assembly work can be made easier, and the overall assembly man-hours can be reduced. Furthermore, since the temperature sensor 80 consists of a cylindrical member 81 that is directly exposed to the hydraulic fluid and a sensor element 82 positioned inside the tip region 80a of the cylindrical member 81, it is possible to detect the temperature of the hydraulic fluid with high accuracy while preventing damage to the sensor element 82 and suppressing the escape of heat from the hydraulic fluid to other components.

[0069] Furthermore, according to the liquid pump device M of the first embodiment, the temperature sensor 80 is positioned to protrude into a passage (discharge passage 14) formed in the housing body 10, and is formed to extend in the same direction as the assembly direction of the motor cover 30 (axis S direction). Therefore, compared to a configuration in which the temperature sensor 80 is positioned to protrude to the outside of the housing, the device can be positioned so that the temperature sensor 80 is directly exposed to the hydraulic fluid without increasing its size.

[0070] Figure 13 shows a temperature sensor 180 included in a liquid pump device according to a second embodiment of the present invention. In this embodiment, a cylindrical member 181 is used in place of the cylindrical member 81 of the temperature sensor 80 of the liquid pump device according to the first embodiment. Components identical to those in the first embodiment are denoted by the same reference numerals and their descriptions are omitted. In the liquid pump device according to the second embodiment, the temperature sensor 180 comprises a cylindrical member 181 and a sensor element 82.

[0071] The cylindrical member 181 is made of resin material and is formed such that its center line C extends parallel to the axis S when assembled, and is equipped with a fitting portion 181a, a large diameter portion 181b, a conical portion 181c, and an annular groove 181d.

[0072] The mating portion 181a is fitted into the mating hole 35 of the motor cover 30. The large-diameter portion 181b is inserted into the through passage 14a of the housing body 10 and fits snugly against the inner wall surface of the through passage 14a. The conical portion 181c has a tip region 180a of the cylindrical member 181, tapering towards the tip compared to the large-diameter portion 181b and forming a bottomed shape, housing the sensor element 82 inside, and is formed to be positioned with a gap between it and the inner wall surface of the through passage 14a when inserted into the through passage 14a of the housing body 10. The annular groove 181d is formed in the region of the large-diameter portion 181b in order to fit the O-ring SR2, which is in close contact with the inner wall surface of the through passage 14a.

[0073] In the assembled state, the temperature sensor 180 according to the second embodiment described above is positioned such that its tip region 180a faces the intersection region Ca of the through passage (first straight passage) 14a and the connecting passage (second straight passage) 14b. As a result, the hydraulic fluid flowing through the communication passage 14b collides with the tip region 180a, then changes direction and flows through the through passage 14a, and is discharged from the discharge port 14a1. In other words, the temperature sensor 180 is positioned to protrude into the discharge passage 14 in order to measure the temperature of the hydraulic fluid. Therefore, the temperature sensor 180 can directly detect the temperature of the hydraulic fluid flowing through the discharge passage 14 without heat being absorbed by intervening materials, as in conventional systems.

[0074] In particular, since the tip region 180a of the temperature sensor 180 not only protrudes into the discharge passage 14 but is also positioned in the intersection region Ca where the direction changes from the connecting passage 14b to the through passage 14a, the hydraulic fluid flows downstream after colliding with the tip region 180a without stagnating. As a result, the temperature of the flowing hydraulic fluid, rather than stagnant hydraulic fluid, can be detected with high accuracy. Furthermore, since the tip region 180a of the temperature sensor 180 is the tip-side region of the tapered cone portion 181c, a gap is formed between it and the inner wall surface of the through passage 14a. Therefore, the tip region 180a The outer wall surface will be reliably exposed to the hydraulic fluid, allowing for more accurate detection of the hydraulic fluid temperature.

[0075] Figures 14 to 18 show a temperature sensor 280 included in a liquid pump device according to the third embodiment of the present invention. In this embodiment, a cylindrical member 281 is used in place of the cylindrical member 81 of the temperature sensor 80 in the liquid pump device according to the first embodiment. Components identical to those in the first embodiment are denoted by the same reference numerals and their descriptions are omitted. In the liquid pump device according to the third embodiment, the temperature sensor 280 comprises a cylindrical member 281 and a sensor element 82.

[0076] The cylindrical member 281 is made of resin material and is formed such that its center line C extends parallel to the axis S when assembled. It includes a fitting portion 281a, a large diameter portion 281b, a small diameter portion 281c, an annular groove 281d, a surrounding wall portion 281e, an outer wall surface 281f, and a plurality of protruding portions 281g.

[0077] The mating portion 281a is fitted into the mating hole 35 of the motor cover 30. The large-diameter portion 281b is inserted into the through passage 14a of the housing body 10 and fits snugly against the inner wall surface of the through passage 14a. The small-diameter portion 281c is located in the tip region 280a of the cylindrical member 281, and is bottomed out towards the tip side of the large-diameter portion 281b, housing the sensor element 82 inside. It is formed to be positioned with a gap between it and the inner wall surface of the through passage 14a when inserted into the through passage 14a of the housing body 10. The annular groove 281d is formed in the large-diameter portion 281b region to accommodate the O-ring SR2, which is in close contact with the inner wall surface of the through passage 14a.

[0078] The surrounding wall portion 281e is formed in a curved shape so as to partially surround the small-diameter portion 281c, with a region facing the connecting passage 14b cut out, in order to cause the hydraulic fluid flowing from the connecting passage 14b toward the small-diameter portion 281c to collide with it. The outer wall surface 281f is formed as a cylindrical surface centered on the center line C, facing the inner wall surface of the through passage 14a with a predetermined gap between them. Multiple protruding portions 281g are formed to project radially from the outer wall surface 281f, extend in the direction of the centerline C, and abut against the inner wall surface of the through passage 14a, in order to define a predetermined gap between the inner wall surface and the outer wall surface 281f of the through passage 14a.

[0079] In the assembled state, the temperature sensor 280 according to the third embodiment described above is positioned such that its tip region 280a faces the intersection region Ca of the through passage (first straight passage) 14a and the connecting passage (second straight passage) 14b, as shown in Figures 17 and 18. As a result, the hydraulic fluid flowing through the communication passage 14b collides with the tip region 280a, then changes direction and flows through the through passage 14a before being discharged from the discharge port 14a1. In other words, the temperature sensor 280 is positioned to protrude into the discharge passage 14 in order to measure the temperature of the hydraulic fluid. Therefore, the temperature sensor 280 can directly detect the temperature of the hydraulic fluid flowing through the discharge passage 14 without heat being absorbed by intervening materials, as in conventional systems.

[0080] In particular, since the tip region 280a of the temperature sensor 280 not only protrudes into the discharge passage 14 but is also positioned in the intersection region Ca where the direction changes from the connecting passage 14b to the through passage 14a, the hydraulic fluid flows downstream after colliding with the tip region 280a without stagnating. As a result, the temperature of the flowing hydraulic fluid, rather than stagnant hydraulic fluid, can be detected with high accuracy. Furthermore, the tip region 280a of the temperature sensor 280 is formed as a small-diameter portion 281c, and a gap is formed between it and the inner wall surface of the through passage 14a. As a result, the outer wall surface of the tip region 280a is reliably exposed to the hydraulic fluid, and the temperature of the hydraulic fluid can be detected with higher accuracy.

[0081] Furthermore, the temperature sensor 280 is provided with a surrounding wall portion 281e made of resin material, which is curved to partially surround the small-diameter portion 281c, in order to cause the hydraulic fluid flowing from the communication passage 14b toward the small-diameter portion 281c to collide with it. As shown in Figure 18, the surrounding wall portion 281e prevents the hydraulic fluid flowing toward the small-diameter portion 281c from coming into contact with the inner wall surface of the through passage 14a of the housing body 10. In other words, it prevents the heat of the hydraulic fluid from being transferred to and diffusing through the housing body 10, which is made of metal material. This allows for highly accurate detection of the hydraulic fluid temperature.

[0082] Furthermore, since the temperature sensor 280 is provided with an outer wall surface 281f that faces the inner wall surface of the through passage 14a with a gap between them, the heat transmitted from the surrounding wall portion 281e to the housing body 10 can be further suppressed. Furthermore, since the temperature sensor 280 is provided with multiple protrusions 281g that project radially from the outer wall surface 281f and abut against the inner wall surface of the through passage 14a, the surrounding wall portion 281e can be fixed to the housing body 10, thereby suppressing or preventing relative vibrations with respect to the housing body 10.

[0083] In the first to third embodiments described above, the temperature sensors 80, 180, and 280 are shown to be positioned so as to protrude into the passage and face the intersection region Ca of the through passage 14a, which is the first straight passage, and the connecting passage 14b, which is the second straight passage. However, the embodiment is not limited to this, and the sensors may be positioned to face the intersection region of the first and second straight passages in other configurations, and the sensor position does not have to be in the intersection region of the two straight passages as long as the sensor is positioned to protrude into the passage.

[0084] In the first to third embodiments described above, the housing H is shown to include a housing body 10, a pump cover 20, a motor cover 30, and an outer cover 40. However, the housing is not limited to this, and a configuration in which the pump cover 20 is omitted and the joint surface of the object to be applied serves as the pump cover may be adopted, or a housing with other configurations may be adopted.

[0085] In the first to third embodiments described above, a discharge passage 14 was used as the passage through which the temperature sensors 80, 180, and 280 are positioned to protrude. However, the invention is not limited to this, and the sensors may also be positioned to protrude into the suction passage that draws hydraulic fluid into the pump chamber of the pump unit 50.

[0086] In the third embodiment described above, the temperature sensor 280 is shown to have an outer wall surface 281f that faces the inner wall surface of the passage 14a with a gap between them and a plurality of protrusions 281g that abut the inner wall surface of the passage 14a. However, the embodiment is not limited to this, and a configuration in which the plurality of protrusions 281g are eliminated and the outer wall surface 281f faces the inner wall surface of the passage 14a with a gap between them or a configuration in which the plurality of protrusions 281g are eliminated and the outer wall surface 281f faces the inner wall surface of the passage 14a in close contact with it may be adopted.

[0087] In the above embodiment, a trochoidal pump unit 50 including an inner rotor 51 and an outer rotor 52 was shown as the pump unit, but it is not limited to this, and a vane-type pump unit or a pump unit of other form may be used. In the above embodiment, a configuration with a filter member 90 was shown, but the invention is not limited to this, and a configuration without the filter member may be adopted, or a configuration in which the filter member is placed on the object to be applied may be adopted.

[0088] As described above, the liquid pump device of the present invention allows for easy integration of a temperature sensor without increasing the size of the device, and can detect the temperature of the liquid with high accuracy. Therefore, it is useful not only for hydraulic oil but also as a liquid pump device for other liquids. [Explanation of symbols]

[0089] 1. Applicable objects M Liquid pump device S axis H Housing 10 Housing body (housing) 11a Joint surface 12 Pump housing recess 13 Motor housing recess 14 Discharge passage (passage) 14a Passage (first straight passage) 14a1 outlet 14b Communication path (second straight path) Ca crossing region 20 Pump cover (housing) 21 Inlet (opening) 30 Motor cover (housing) 40 Outer cover (housing) 50 Pump Units 51 Inner Rotor 52 Outer rotor 60 motors 63 Drive shaft 70 Circuit boards 71 Control Unit 80 Temperature Sensor C center line 80a tip area 81 Cylindrical member 81b Large diameter section 81c Small diameter section 82 sensor elements 90 Filter component 180 Temperature Sensor 181 Cylindrical member 180a tip area 181 Cylindrical member 181b Large diameter section 181c Cone section 280 Temperature Sensor 281 Cylindrical member 280a tip area 281 Cylindrical member 281b Large diameter section 281c Small diameter section 281e Enclosing wall 281f Exterior wall 281g Multiple protruding parts

Claims

1. A pump unit that rotates to make the liquid flow, A housing that accommodates the pump unit and defines a passage for the liquid, The system includes a temperature sensor, which includes a bottomed cylindrical member inserted into the passage to measure the temperature of the liquid flowing through the passage, The cylindrical member is made of a resin material and includes a small diameter portion that is positioned at its tip with a gap from the inner wall surface of the passage and houses a sensor element, and a surrounding wall portion that partially surrounds the small diameter portion by being cut out in a region facing the upstream side of the passage in order to restrict liquid flowing from the upstream side of the passage, passing around the small diameter portion and to the downstream side of the passage, from colliding with the inner wall surface around the small diameter portion. A liquid pump device characterized by the following features.

2. The surrounding wall portion has an outer wall surface that faces the inner wall surface of the passage. The liquid pump device according to feature 1.

3. The surrounding wall portion has a plurality of protrusions that project from the outer wall surface and abut against the inner wall surface of the passage in order to define a gap between the inner wall surface and the outer wall surface of the passage. The liquid pump device according to feature 2.

4. A pump unit that rotates to make a liquid flow, A housing that accommodates the pump unit and defines a passage for the liquid, A motor having a drive shaft that rotates around a predetermined axis in order to rotationally drive the pump unit, A circuit board on which a control unit for controlling the drive of the motor is mounted, The system includes a temperature sensor connected to the circuit board and positioned with its tip protruding into the passage, for measuring the temperature of the liquid flowing through the passage. The housing includes a housing body that defines a joining surface to be joined to an object to be applied, a pump housing recess for housing the pump unit, a motor housing recess for housing the motor, a through passage extending parallel to the axis to form part of the passage and penetrating through to the joining surface, and a communication passage extending inclined with respect to the axis to form part of the passage and connecting the pump housing recess to the through passage, and a pump cover that is joined to the housing body to cover the pump housing recess and defines an opening for the passage of liquid. The temperature sensor is positioned such that its tip faces the intersection region of the through passage and the communication passage. A liquid pump device characterized by the following features.

5. The housing includes a motor cover that is joined to the housing body to cover the motor housing recess, The temperature sensor includes a bottomed cylindrical member provided in the motor cover and inserted into the through passage, and a sensor element electrically connected to the circuit board and positioned in the tip region within the cylindrical member. The liquid pump device according to feature 4.

6. The cylindrical member includes a large-diameter portion that fits into the inner wall surface of the through passage, and a small-diameter portion that has a bottomed shape towards the tip of the large-diameter portion, is positioned with a gap between it and the inner wall surface of the through passage, and houses the sensor element. The small-diameter portion is located in the intersection region of the through passage and the connecting passage. The liquid pump device according to feature 5.

7. The cylindrical member is made of a resin material and includes a surrounding wall portion which is curved so as to partially surround the small diameter portion by cutting out the region facing the passage. The liquid pump device according to feature 6.

8. The surrounding wall portion has an outer wall surface that faces the inner wall surface of the through passage. The liquid pump device according to feature 7.

9. The surrounding wall portion has a plurality of protruding portions that extend from the outer wall surface and abut against the inner wall surface of the passage in order to define a gap between the inner wall surface and the outer wall surface of the passage. The liquid pump device according to feature 8.

10. The housing includes an outer cover that is joined to the motor cover to cover the circuit board located outside the motor cover, The liquid pump device according to feature 5.

11. The passage in which the temperature sensor is located is a discharge passage for discharging the liquid pressurized by the pump unit. A liquid pump device according to any one of features 1 to 10.

12. The pump unit includes a filter member positioned upstream of the suction port into which the liquid is drawn, The liquid pump device according to feature 11.

13. The pump unit is a trochoidal type pump unit including an inner rotor and an outer rotor. The liquid pump device according to feature 12.

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