JP2013234611A - Electric pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric pump capable of cooling the electric pump by a fluid circulating through a bypass passage and having a simple connection structure between the bypass passage and a pump part.SOLUTION: An electric pump includes a relief valve V opening a bypass passage 22 when a pressure of a discharge fluid from a pump part 4 becomes equal to or higher than a set pressure. A branch part 24 from a pump discharge passage 16 to the bypass passage 22 and a confluence part 25 from the bypass passage 22 to a pump suction passage 17 are formed at the side of the cover member 7b. The bypass passage 22 passes through a joining part between a case end face 9 of a case body 7a and a cover end face 10 of the cover member 7b, and a portion of the bypass passage 22 is provided at the side closer to the case body 7a than the branch part 24 and the confluence part 25.

Description

  The present invention includes a stator having a plurality of coils arranged in the circumferential direction, a motor unit including a motor rotor that rotates by energization of the coils, a pump unit that is driven by the rotational power of the motor unit, the motor unit, The case includes: a case main body, wherein the pump portion is concentrically arranged, and a pump housing portion that houses the pump portion is formed to open to an end surface of the case; and the opening of the pump housing portion is closed. A cover member having a cover end surface joined to the end surface, a discharge path and a suction path of the pump unit formed in the cover member, and a bypass path for sucking the discharge fluid discharged from the discharge path into the suction path And a relief valve that opens the bypass when the pressure of the discharged fluid is equal to or higher than a set pressure.

The electric pump opens the bypass passage with a relief valve when the pressure of the discharge fluid from the pump portion exceeds a set pressure so that the load on the motor portion does not become excessive, and the discharge fluid is pumped through the bypass passage. Is configured to be inhaled.
Patent Document 1 describes an electric pump provided with a bypass passage so that a heat generating part of the electric pump can be cooled by a fluid flowing through the bypass passage.
In addition to the discharge path and suction path formed in the cover member, the bypass path provided in the electric pump is provided inside the case body on the opposite side of the discharge path and suction path with the pump portion interposed therebetween. Yes. When a relief valve is provided at the position of the bypass passage and the discharge pressure of the pump unit increases, the relief valve opens and fluid flows along the wall surface of the control unit provided adjacent to the pump unit. It is configured to flow.
Patent Document 1 describes that this configuration shortens the distance of the bypass flow path and enables the power control unit to be cooled.

JP 2009-162146 A

However, in order to form such a bypass path, the entire electric pump must be designed to meet the specifications. For this reason, when there are various sizes of electric pumps, the electric pumps must be individually designed, and a new electric pump cannot be obtained efficiently.
Further, in this pump, the length of the bypass path needs to be shortened, so that the installation location of the bypass flow path and the relief valve is limited to a very narrow area on one side of the pump rotor in the case body. As a result, although the heat generating part is cooled using the fluid, only a part of the wall surface of the power control part is cooled, and a sufficient cooling effect for the heat generation of the entire pump cannot be obtained.

  The present invention has been made in view of the above circumstances, and it is possible to cool an electric pump with a fluid flowing through the bypass passage, and to provide an electric pump with a simple connection structure between the bypass passage and the pump section. Objective.

  A first characteristic configuration of an electric pump according to the present invention is driven by a motor unit including a stator in which a plurality of coils are arranged in a circumferential direction, a motor rotor that rotates by energization of the coils, and rotational power of the motor unit. A pump body, a case main body in which the motor section and the pump section are concentrically arranged, and a pump housing section that houses the pump section is formed to open to a case end surface; and the pump housing section A cover member having a cover end surface joined to the case end surface so as to close the opening, a discharge path and a suction path of the pump portion formed in the cover member, and a discharge fluid discharged from the discharge path A bypass passage for sucking into the suction passage, and a relief valve that opens the bypass passage when the pressure of the discharge fluid exceeds a set pressure, And a junction from the bypass path to the suction path is formed on the cover member side, the bypass path passes through a joint portion between the case end surface and the cover end surface, and one of the bypass paths. The portion is provided on the side of the case body with respect to the branch portion and the junction portion.

  In the electric pump of this configuration, a branch portion from the discharge passage to the bypass passage and a joining portion from the bypass passage to the suction passage are formed on the cover member side, and the bypass passage is formed on the case end surface and the cover. While passing through the joint with the end face, a part of the bypass path is provided closer to the case body than the branching part and the joining part.

In particular, a branch part from the discharge path to the bypass path and a junction part from the bypass path to the suction path are formed on the cover member side, and the bypass path passes through the joint between the case end surface and the cover end surface, and the bypass path Is provided on the side of the case main body with respect to the branch portion and the junction portion formed on the cover member side. Therefore, it is possible to effectively cool the case main body, in which the motor part that easily generates heat when energized is provided, with the fluid flowing through the bypass.
In the case of this configuration, for example, the branch portion and the merging portion are provided on the cover end surface of the cover member facing the case main body, and the bypass path is provided in a state of penetrating the inside of the case main body, Various configurations can be employed, such as providing the merging portion on the outer surface side of the cover member and providing a bypass path at a joint portion between the cover end surface of the cover member and the case end surface of the case body.

  According to a second characteristic configuration of the present invention, the case main body includes a first case portion in which the stator is provided and a second case portion in which the pump housing portion is formed in the direction of the rotation axis of the motor rotor. It is divided and joined to each other, and the bypass path is formed along the joint portion between the first case portion and the second case portion.

  The first case portion is provided with a stator that is a heat generating portion. As in this configuration, by providing the bypass path along the joint portion between the first case portion and the second case portion, heat generated from the stator can be effectively removed, and the cooling effect of the entire pump can be enhanced. .

  A third characteristic configuration of the present invention lies in that the bypass path is disposed at a position overlapping the stator in the direction of the rotation axis of the motor rotor.

  If it is this structure, the temperature rise of the stator accompanying the electricity supply to a coil can be suppressed effectively, and durability of a stator can be improved.

The longitudinal cross-sectional view of the electric pump in 1st Embodiment II-II sectional view of FIG. III-III sectional view of FIG. Disassembled perspective view of electric pump 3 is a cross-sectional view taken along line VV in FIG. 3 showing a state where the relief valve is closed. 3 is a cross-sectional view taken along the line VV in FIG. 3 showing a state in which the relief valve is open. Cross-sectional view of the electric pump in the second embodiment Longitudinal sectional view of the electric pump in the third embodiment Vertical sectional view of the electric pump in the fourth embodiment

Hereinafter, some embodiments according to the present invention will be described with reference to the drawings.
[First Embodiment]
FIGS. 1-6 shows the electric pump with which the lubrication oil supply system in a motor vehicle engine is equipped.
As shown in FIGS. 1 and 2, the electric pump includes a stator 1 provided with a plurality of coils 1a in the circumferential direction, a motor unit 3 including a motor rotor 2 that rotates by energization of the coils 1a, and a motor unit. 3, a pump unit 4 driven by the rotational power 3, a shaft 5 formed of a metal material such as steel that transmits the rotational power of the motor unit 3 to the pump unit 4, and a control unit 6 that controls the operation of the electric pump. And a case 7 made of metal or resin whose outer shape that accommodates the motor unit 3, the pump unit 4 and the control unit 6 is substantially cylindrical.

  The case 7 includes a motor body 3 and a pump part 4 concentrically arranged, and a case main body 7a formed so that a pump housing part 8 for housing the pump part 4 opens in the case end surface 9; A thick plate-like cover member 7 b having a cover end surface 10 joined to the case end surface 9 and a control cover 7 c forming an accommodation space 6 a of the control unit 6 are provided so as to close the opening of the portion 8.

The case body 7a includes a first case portion 11 on which the stator 1 is provided and a second case portion on which the pump housing portion 8 is formed in the direction of the rotation axis X of the motor rotor 2 (rotation axis of the shaft 5). 12 is divided.
The first case part 11 includes a cylindrical part 11a in which the stator 1 is insert-molded, and a partition wall 11b that partitions the inner peripheral side of the cylindrical part 11a in a liquid-tight manner into the motor rotor 2 side and the control unit 6 side. have.
The second case portion 12 includes a cylindrical bearing portion 12a that rotatably supports the shaft 5, and a cylindrical fitting portion 12b that is concentrically fitted in the cylindrical portion 11a of the first case portion 11. The bearing portion 12 a is formed so as to enter the inner peripheral side of the motor rotor 2.

A fitting portion 12b of the second case portion 12 is fitted to one end side of the cylindrical portion 11a to form a rotor accommodating space 13 for accommodating the motor rotor 2 between the partition wall 11b and the second case portion 12. is there. Further, the control cover 7c is fitted and fixed to the other end side of the cylindrical portion 11a, and a unit accommodation space 6a for accommodating the control unit 6 is formed between the partition wall 11b and the control cover 7c.
The control unit 6 includes a substrate 6b including a driver circuit having, for example, a power transistor and a sensing processing unit that determines the rotational phase of the motor rotor 2.

The motor rotor 2 is formed in a ring shape including a plurality of permanent magnets 2a arranged in the circumferential direction on the outer peripheral side and a back yoke 2b that holds the permanent magnets 2a.
The plurality of permanent magnets 2a are arranged such that N poles and S poles are alternately arranged in the circumferential direction. The back yoke 2b is a laminate of thin ferromagnetic plates such as iron.

The rotor 15 of the motor rotor 2 is configured by insert-molding the motor rotor 2 into a resin disk-like member 14 in which a boss portion 14 a through which the shaft 5 is inserted is formed.
The rotor 15 is supported by the second case portion 12 via the shaft 5 inserted through the boss portion 14a so that the motor rotor 2 rotates on the inner peripheral side of the cylindrical portion (stator 1) 11a.

The pump unit 4 includes an outer rotor 4a in which trochoidal inner teeth are formed on the inner peripheral side, and an inner rotor 4b in which outer teeth meshing with the inner teeth on the inner peripheral side of the outer rotor 4a are formed on the outer peripheral side. It is composed of a trochoid gear pump and accommodated in the pump accommodating portion 8.
A discharge path 16 through which hydraulic oil is discharged from the pump unit 4 and a suction path 17 through which hydraulic oil is sucked are formed through the cover member 7b.

The outer rotor 4a and the inner rotor 4b are formed with the same thickness, and the pump housing portion 8 is formed with a concave portion having a cylindrical inner peripheral surface having a length substantially the same as the thickness of the rotors 4a and 4b. .
The outer rotor 4a is accommodated so as to be slidably rotatable along the inner peripheral surface of the pump accommodating portion 8 around an eccentric axis Y that is eccentric with respect to the rotation axis X of the inner rotor 4b.

The shaft 5 fixes the rotor 15 of the motor rotor 2 on one end side and the inner rotor 4 b on the other end side, and transmits the rotational power of the motor rotor 2 to the pump unit 4.
The shaft 5 is mounted such that one end enters the recess 5a formed in the cover member 7b and the other end enters the recess 5b formed in the partition wall 11b.

The first case portion 11 and the second case portion 12 are provided with flange portions 19a and 19b in which bolt insertion holes 18a and 18b are formed, and the female screw hole 18c is formed in the cover member 7b. A flange portion 19c is provided.
The head bolt 20 inserted into the bolt insertion holes 18a and 18b is tightened into the female screw hole 18c, and the first case portion 11, the second case portion 12, and the cover member 7b are integrally connected.

A seal ring 21 is attached to each of a joint portion between the first case portion 11 and the second case portion 12 and a joint portion between the second case portion 12 and the cover member 7b, and a case of oil (an example of fluid). Leakage to the outside is prevented.
In addition, a seal ring 33 is mounted on the outer peripheral side of the fitting portion 12b in the second case portion 12, so that hydraulic fluid leaks into the rotor housing space 13 from between the fitting portion 12b and the cylindrical portion 11a. It is preventing.
Further, a sealing material 34 is annularly mounted on the inner peripheral side of the bearing portion 12 a in the second case portion 12, and hydraulic oil is transferred from the pump portion 4 to the rotor accommodating space 13 through the space between the bearing portion 12 a and the shaft 5. Prevents leakage.
When the motor rotor 2 is configured to allow contact with the hydraulic oil, the seal ring 33 and the seal material 34 are not particularly required.

  As shown in FIG. 3 to FIG. 6, a bypass path 22 that sucks hydraulic oil (discharge fluid) discharged from the discharge path 16 into the suction path 17 and returns to the pump section 4, and from the pump section 4 to the discharge path 16. A relief valve V that opens the bypass passage 22 is provided so that when the pressure of the discharged hydraulic oil becomes equal to or higher than the set pressure, the hydraulic oil flows.

The cover member 7 b is formed with a branch portion 24 from the discharge passage 16 to the bypass passage 22 and a junction portion 25 from the bypass passage 22 to the suction passage 17.
The bypass path 22 is provided across the cover member 7 b and the second case part 12 through the joint between the case end surface 9 and the cover end surface 10, and a part of the bypass path 22 with respect to the branch part 24 and the junction part 25. It is provided on the case body 7a side.
Therefore, the branch portion 24 constitutes the start end portion of the bypass path 22, and the junction portion 25 constitutes the end portion of the bypass path 22.

  As shown in FIGS. 5 and 6, the relief valve V is attached to the cover member 7 b and connected to a midway portion of the bypass path 22. When the hydraulic oil pressure (pressure of the discharged fluid) in the primary flow path 23a becomes equal to or higher than the set pressure, the spool valve body 23 is retracted against the biasing force of the coil spring 23c as shown in FIG. 23a and the secondary side flow path 23b are connected.

  As shown in FIGS. 1 and 4, the cover end surface 10 of the cover member 7 b is formed with a branch path groove 24 a that forms the branch section 24 from the discharge path 16 and a merging section 25 to the suction path 17. A joint channel groove 25a is formed. Therefore, the branch portion 24 and the junction portion 25 are formed between the cover end surface 10 and the case end surface 9 by joining the cover end surface 10 to the case end surface 9 and connecting the cover member 7b and the second case portion 12. Is done.

  The bypass path 22 includes a branch-side flow path 26 that communicates with the branch portion 24, a first flow path 27 that is arranged in an arc around the rotation axis X that communicates with the branch-side flow path 26 on the upstream side, Relieve the confluence side flow path 28 communicating with the confluence 25, the arc-shaped second flow path 29 around the rotation axis X communicating with the confluence side flow path 28 on the downstream side, and the downstream side of the first flow path 27. A first communication path 30 that communicates with the primary flow path 23a of the valve V; and a second communication path 31 that communicates the upstream side of the second flow path 29 with the secondary flow path 23b of the relief valve V. Yes.

Each of the branch side flow path 26, the merge side flow path 28, the first communication path 30, and the second communication path 31 is formed through the second case portion 12 in the direction of the rotation axis X.
The first flow path 27 and the second flow path 29 are formed on the second case portion joint surface 32 that joins the second case portion 12 to the first case portion 11. An arc-shaped second flow passage groove 29 a is formed along the joint portion between the second case portion 12 and the first case portion 11.

  The bypass path 22 is disposed at a position overlapping the stator 1 when viewed in the direction along the rotation axis X. Thereby, when the temperature of the stator 1 rises as the coil 1a is energized, the generated heat can be effectively removed, and the durability of the electric pump can be improved.

  The first case portion 11, the second case portion 12, and the cover member 7 b are connected to each other by a headed bolt 20. As a result, the branch side flow path 26 is connected to the branch portion 24, the merging side flow path 28 is connected to the merging portion 25, and the relief valve V is connected to the middle of the bypass path 22.

  When the pressure of the hydraulic oil discharged from the pump unit 4 becomes equal to or higher than the set pressure, the first flow path 27 and the second flow path 29 communicate with each other via the relief valve V as shown in FIG. Part of the hydraulic oil discharged from the pump is sucked into the pump unit 4 through the bypass 22.

As in the present embodiment, a part of the bypass path 22 is made of, for example, a heating element with respect to the position of the branching section 24 from the discharge path 16 to the bypass path 22 and the junction 25 from the bypass path 22 to the suction path 17. By providing an offset on the side of a certain stator 1, the efficiency of removing heat generated in the stator 1 or the like is increased, and the temperature rise of the electric pump is suppressed.
In addition, this configuration is advantageous in terms of cost because a pump having a high cooling effect can be obtained by improving only the cover member 7b side of the pump body used conventionally.

[Second Embodiment]
In the first embodiment, as shown in FIG. 3, arc-shaped bypass paths 22 on the back side of the cover member 7b are formed at two locations. This is because the branch portion 24 from the discharge passage 16, the junction portion 25 to the suction passage 17, and the relief valve V are provided outside the cover member 7b, so that the branch portion 24 and the junction portion 25 respectively. This is because it is necessary to once pass the extending bypass path 22 to the opposite side of the cover member 7b and to return the bypass path 22 to the outside of the cover member 7b so as to connect the bypass path 22 to the relief valve V. However, with this configuration, the length of the bypass path 22 installed on the side of the stator 1 that is a heat source is shortened, and there is room for improvement in order to enhance the cooling effect.

  Therefore, as shown in FIG. 7, the relief valve V is arranged in series on the outer surface side of the cover member 7b and immediately after the branching portion 24 from the discharge passage 16, and between the second case portion 12 and the cover member 7b. The bypass path 22 is formed in a substantially circular arc shape around the rotation axis X to ensure the maximum length of the bypass path 22. If it is this structure, the heat_generation | fever from the stator 1 grade | etc., Will be absorbed to the maximum, and a cooling effect can be improved. In this case, it is preferable that the relief valve V is formed integrally with the cover member 7b, because the size of the entire pump is reduced and the number of assembly steps of the pump is reduced.

[Third Embodiment]
In FIG. 8, 2nd Embodiment about the electric pump of this invention is shown.
In this embodiment, a part of the branch part 24 from the discharge path 16 to the bypass path 22 and a part of the merge part 25 from the bypass path 22 to the suction path 17 are provided on the outer surface side of the cover member 7b. The relief valve V is arranged in series immediately below the branch portion 24. If these branch part 24, merge part 25, and relief valve V are formed integrally with the cover member 7b, the assembly man-hour of the pump is reduced and the size of the cover member 7b along the axial direction X can be easily reduced. preferable.

  By providing the bypass path 22 between the second case portion 12 and the cover member 7b as described above, the bypass path 22 has a substantially circular shape on the back side of the cover member 7b. Also in this configuration, the bypass path 22 is deviated toward the stator 1 along the direction of the rotation axis X with respect to the positions of the branching section 24 and the joining section 25, so that the cooling of the entire electric pump is performed. The effect can be enhanced.

[Fourth Embodiment]
As shown in FIG. 9, the electric pump according to the present invention can be implemented even in a configuration in which the motor rotor 2 and the pump rotor 4 are in contact with each other and no wall portion exists between them. In this case, the motor rotor 2 and the inner rotor 4 b rotate integrally, and the outer rotor 4 a slides and rotates with respect to the motor rotor 2. The outer rotor 4a rotates while being guided by the inner peripheral surface of the case body 7a.

In the present embodiment, as in the third embodiment, the cover member 7b includes a part of the branch part 24 from the discharge path 16 to the bypass path 22 and a part of the merge part 25 from the bypass path 22 to the suction path 17. It is provided on the outer surface side.
In addition, you may form the branch part 24, the confluence | merging part 25, and the relief valve V integrally with the cover member 7b, for example on the outer surface side of the cover member 7b.
On the other hand, the bypass path 22 is provided along the joint between the case body 7a and the cover member 7b. The groove portion constituting the bypass path 22 may be formed on either the case body 7a side or the cover member 7b side, or may be formed on both sides.
If it is this structure, the size of an electric pump can be compactized along the direction of the rotating shaft core X, improving the cooling effect of an electric pump.

[Other Embodiments]
In the electric pump according to the present invention, the relief valve V may be provided at any position in the middle of the bypass path 22, for example, may be provided in the middle of the merging portion 25.

  The shape of the bypass path 22 is not limited to the groove shape as described above, and may be, for example, a hole shape formed so as to penetrate the inside of the case main body 7a or the cover member 7b.

  The type of the electric pump may use, as a pump part, a gear pump that sucks and discharges fluid with a pair of external gears that mesh with each other in addition to a vane pump.

  The electric pump according to the present invention is applicable to various types of electric pumps that have both a motor unit and a pump unit and need to remove heat generated by the motor unit or heat generated by the motor control unit or the like.

DESCRIPTION OF SYMBOLS 1 Stator 1a Coil 2 Motor rotor 3 Motor part 4 Pump part 7a Case main body 7b Cover member 8 Pump accommodating part 9 Case end surface 10 Cover end surface 11 First case part 12 Second case part 16 Discharge path 17 Suction path 22 Bypass path 24 Branch part 25 Junction V Relief Valve X Rotating Shaft Core

Claims (3)

A motor unit including a stator in which a plurality of coils are disposed in the circumferential direction and a motor rotor that rotates by energization of the coils;
A pump unit driven by the rotational power of the motor unit;
A case main body having the motor part and the pump part arranged concentrically, and a pump housing part that houses the pump part is formed to open to a case end surface;
A cover member having a cover end surface joined to the case end surface so as to close the opening of the pump housing portion;
A discharge path and a suction path of the pump portion formed in the cover member;
A bypass path for sucking the discharge fluid discharged from the discharge path into the suction path;
A relief valve that opens the bypass when the pressure of the discharge fluid is equal to or higher than a set pressure,
A branch portion from the discharge passage to the bypass passage and a joining portion from the bypass passage to the suction passage are formed on the cover member side,
The electric pump in which the bypass passage passes through a joint portion between the case end surface and the cover end surface, and a part of the bypass passage is provided closer to the case body than the branch portion and the junction portion. The case main body is divided into a first case portion provided with the stator and a second case portion forming the pump housing portion and joined to each other in the direction of the rotational axis of the motor rotor;
The electric pump according to claim 1, wherein the bypass path is formed along a joint portion between the first case portion and the second case portion.   3. The electric pump according to claim 1, wherein the bypass path is disposed at a position overlapping the stator when viewed in the direction of the rotational axis of the motor rotor.

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