WO2022202422A1

WO2022202422A1 - Electric pump

Info

Publication number: WO2022202422A1
Application number: PCT/JP2022/011110
Authority: WO
Inventors: 直嗣北山; 正浩川合; 慎太朗石川
Original assignee: Ntn株式会社
Priority date: 2021-03-24
Filing date: 2022-03-11
Publication date: 2022-09-29

Abstract

This electric pump is provided with a motor unit 3, a pump unit 2, a housing 5 which houses the motor unit 3 and the pump unit 2, an intake port 63 and a discharge port 65 which are formed in the surface of the housing 5, an intake pipeline 60 which allows communication between the intake port 63 and the pump unit 2, a discharge pipeline 61 which allows communication between the discharge port 65 and the pump unit 2, and a check valve mechanism 70 which is provided in the discharge pipeline 61.

Description

electric pump

The present invention relates to an electric pump.

In recent years, vehicles such as automobiles may use an electric oil pump to supply oil to each part of the vehicle. For example, a vehicle equipped with an idling stop mechanism (a mechanism for automatically stopping the engine when the vehicle is stopped) or a hybrid vehicle is provided with an electric oil pump that supplies hydraulic pressure to the transmission while the engine is stopped.

In this case, if the oil in the oil passage of the transmission reverses for some reason, the oil will flow from the discharge side of the electric oil pump, and this hydraulic pressure will cause the pump to rotate in the reverse direction, damaging the motor and controller that mainly drive the pump. There is a risk of

For example, Patent Literature 1 below discloses a configuration that prevents backflow of oil by providing a check valve in the oil passage of the transmission.

Japanese Patent No. 6224521

As described above, when a check valve is installed in the oil passage of the transmission, it is necessary to change the design of the oil passage of the transmission in order to install the check valve, so design man-hours are required.

The problems described above can occur not only in electric oil pumps, but also in electric pumps that pump liquids other than oil.

Therefore, the first object of the present invention is to prevent damage to the electric pump due to backflow of the liquid (oil, etc.) to be pumped without increasing the man-hours for designing the parts to be attached (for example, the transmission).

In addition, the inventors considered providing a check valve in the electric oil pump instead of the transmission. Specifically, as shown in FIG. 19, a check valve mechanism 170 is provided in a discharge pipe line 161 formed in a housing 150 of the electric oil pump. As shown in FIGS. 19 and 20, the check valve mechanism 170 has a ball 171, a spring 172, a holding portion 173 that holds them on the inner periphery, and a seal surface 174. As shown in FIG. A sealing surface 174 is formed on the housing 150 of the electric oil pump. In the illustrated example, the discharge pipe line 161 has a small-diameter portion 161a and a large-diameter portion 161b, and a seal surface 174 is formed at the inner diameter end of the stepped portion 161c connecting them.

The holding part 173 has a holder 175 and a retaining member 176 . A ball 171 and a spring 172 are arranged on the inner periphery of the holder 175 , and a retainer member 176 is press-fitted into the large-diameter portion 161 b of the discharge pipe 161 . The urging force of the spring 172 presses the ball 171 against the seal surface 174, thereby closing the discharge line 161. As shown in FIG. When the electric oil pump is driven and oil is discharged to the discharge pipe line 161, the ball 171 is pushed down by the oil pressure and separated from the seal surface 174 (see the dotted line in FIG. 19). As a result, the oil wraps around the outer periphery of the ball 171 and is discharged from the oil discharge port 165 provided at the lower end of the discharge pipe line 161 (see dotted arrow A).

When assembling the check valve mechanism 170 to the housing 150, the ball 171, the spring 172, and the holder 175 are inserted from the oil outlet 165 into the discharge pipe 161 in this order. However, since it takes time and effort to insert each part into the discharge pipe 161 one by one and assemble it, the assembly equipment becomes complicated and expensive.

Therefore, the second object of the present invention is to improve the ease of assembly of a check valve mechanism to an electric oil pump or the like, and to simplify assembly equipment and reduce costs.

In order to achieve the first object, the first invention of the present application comprises a motor section, a pump section driven by the motor section, a housing that accommodates the motor section and the pump section, and a surface of the housing. a suction port and a discharge port that are formed; a suction conduit that communicates the suction port and the pump section; a discharge conduit that communicates the discharge port and the pump section; Provided is an electric pump equipped with a check valve mechanism.

In this way, by providing a check valve mechanism in the discharge pipe of the electric pump, it is possible to prevent backflow of liquid (for example, oil) to the pump section without changing the design of the oil passage of the transmission. It is possible to prevent the failure of the motor part associated with this.

The above check valve mechanism can include a ball, a sealing surface, a biasing member that presses the ball against the sealing surface, and a retaining portion that retains the ball and the biasing member on the inner periphery. Thus, by holding the ball and the biasing member from the outer periphery by the holding portion, the positions and postures of the ball and the biasing member can be stabilized.

For example, as shown in FIG. 10, the discharge pipe 103 can be closed by bringing a ball 101 into contact with a sealing surface 102 (corner) formed on the discharge pipe 103 . In this case, the contact angle α between the ball 101 and the seal surface 102 (the angle formed by the tangent line of the outer peripheral surface of the ball 101 at the contact portion between the ball 101 and the seal surface 102 in the cross section passing through the center line L′ of the discharge pipe 103 ) is small, the ball 101 may get caught in the sealing surface 102 and become difficult to separate from the sealing surface 102, which may hinder the discharge of the liquid. Therefore, it is preferable that the contact angle α between the ball and the seal surface is increased to some extent, specifically, 20° or more.

In the above electric pump, if the holding portion of the check valve mechanism is retracted to the upstream side of the discharge port of the housing, the holding portion is completely housed inside the housing, thereby preventing interference with other members. . On the other hand, if the holding portion of the check valve mechanism protrudes from the discharge port of the housing, the protruding portion can be used as a positioning reference when attaching the electric pump to another component (eg, transmission case). Therefore, if the holding portion can be arranged either at a position protruding from the discharge port of the housing or at a position retracted upstream of the discharge port of the housing, the functions described above can be selectively provided. can do.

The holding part of the check valve mechanism can have a holder and a retaining member. A ball and a biasing member are arranged on the inner periphery of the holder. The holder can be easily inserted into the discharge pipeline by inserting the holder into the inner periphery of the discharge pipeline through a gap. The retaining member is fixed to the discharge pipeline. By bringing this retaining member into contact with the holder from the downstream side, it is possible to prevent the holder from coming off from the discharge pipe.

When the holder is arranged on the inner circumference of the discharge pipe with a gap therebetween as described above, the holder can rotate inside the discharge pipe. Holding of the member may become unstable. Further, when the holder rotates, the holder slides against the retainer member and the housing, so there is a risk that the holder will wear out due to long-term use. Therefore, it is preferable to engage the holder and the retaining member in the circumferential direction of the discharge pipe to restrict the rotation of the holder.

When the housing is integrally formed as one piece and includes a housing body that accommodates the motor section and the pump section, the housing body can be formed with a discharge line. In this case, the holding portion of the check valve mechanism can be arranged in the large-diameter portion of the discharge pipeline. If the large-diameter portion of the discharge pipe is not provided with a check valve mechanism, the reverse flow of the liquid cannot be prevented, but the discharge pipe functions without any problem. Therefore, the common housing can be used whether or not the check valve mechanism is provided, so that the manufacturing cost can be reduced.

The sealing surface of the check valve mechanism can be formed, for example, on the housing body. For example, the discharge pipe may be provided with a stepped portion connecting the inner peripheral surface of the small diameter portion and the inner peripheral surface of the large diameter portion, and the sealing surface may be formed on the stepped portion.

When forming the sealing surface on the housing body, the sealing surface can be formed by pressing a ball or a jig having a molding surface of the same shape against the housing. In this case, the sealing surface is a plastically worked surface having the same shape as the outer peripheral surface of the ball. By forming the sealing surface into the same shape as the ball in this way, the adhesion between the ball and the sealing surface is enhanced, and the sealing performance is enhanced.

　The electric pump can be made compact by arranging the discharge pipe in the area between the motor part and the pump part in the axial direction.

As the pump unit, for example, a rotary pump (for example, a trochoid pump) that pumps liquid by rotating can be used.

In order to achieve the second object, the second invention of the present application comprises a seal surface, a ball, a biasing member that biases the ball upstream and presses it against the seal surface, the ball and the seal surface. A check valve mechanism comprising a holder that holds an urging member on the inner circumference, wherein the holder is capable of engaging with a support portion that supports the urging member from the downstream side and the ball from the upstream side. A check valve mechanism having a locking portion is provided.

In this way, by providing the support portion and the locking portion to the holding portion, it is possible to prevent the ball and the biasing member from falling off from the inner circumference of the holding portion. It can be handled integrally as a valve part unit. By assembling the integrated check valve component unit to the housing or the like of the electric oil pump, the assembling efficiency is improved as compared with the case where each component is assembled one by one.

The locking portions can be provided, for example, at a plurality of locations spaced apart in the circumferential direction of the holder.

It is preferable that the engaging portion can be elastically displaced radially to a position that allows passage of the ball. As a result, the ball can be easily incorporated into the inner periphery of the holding portion by pushing the ball into the inner periphery of the locking portion and passing the ball while elastically displacing the locking portion toward the outer diameter side. .

By making the inner diameter of the locking portion smaller than the diameter of the ball, the locking portion can be engaged with the ball. Further, by making the inner diameter of the locking portion larger than the outer diameter of the biasing member, the biasing member can be inserted into the inner circumference of the holding portion from the side of the locking portion (upstream side).

The holder can be configured to have a plurality of guide portions extending along the direction of the flow path. In this case, a locking portion can be provided at the tip of each guide portion.

The check valve mechanism described above can be configured such that the locking portion and the ball are separated from each other while the ball is in contact with the sealing surface. In this case, since the ball abuts against the sealing surface before contacting the locking portion, the locking portion does not come into contact with the ball. That is, the locking portion functions to prevent the ball from jumping out of the holding portion before the check valve mechanism is incorporated into the target component.

The above check valve mechanism is incorporated into an electric oil pump, for example. The electric oil pump includes a motor portion, a pump portion driven by the motor portion, a housing that accommodates the motor portion and the pump portion, and an oil suction port and an oil discharge port that are formed on the surface of the housing. a suction pipe communicating between the oil suction port and the pump portion; a discharge pipe communicating between the oil discharge port and the pump portion; and the check valve mechanism provided in the discharge pipe. Prepare. In this case, the sealing surface of the check valve mechanism can be formed on the housing.

As described above, in the first invention of the present application, by providing the check valve mechanism in the discharge pipe, it is possible to prevent damage to the electric pump due to backflow of liquid without increasing the number of man-hours for designing the parts to be attached.

In addition, as in the second invention of the present application, by providing the retaining portion of the check valve mechanism with a locking portion that prevents the ball from jumping out, the ease of assembly of the check valve mechanism to an electric oil pump or the like is improved. Equipment can be simplified and costs can be reduced.

1 is an axial cross-sectional view of an electric oil pump according to an embodiment of the first invention of the present application; FIG. FIG. 2 is a cross-sectional view in the direction perpendicular to the axis taken along line II-II of FIG. 1; It is a perspective view of the said electric oil pump. FIG. 4 is a cross-sectional view of a check valve mechanism provided in the electric oil pump; 4 is a perspective view of components of the check valve mechanism; FIG. 4 is an enlarged cross-sectional view of the ball and seal surface of the check valve mechanism; FIG. FIG. 4 is a cross-sectional view showing a method of forming a sealing surface of the check valve mechanism; FIG. 5 is a cross-sectional view of a check valve mechanism according to another embodiment; FIG. 8 is a cross-sectional view of a check valve mechanism according to still another embodiment; FIG. 4 is a cross-sectional view of a ball and a seal surface according to a reference example; FIG. 8 is a cross-sectional view of a check valve mechanism according to an embodiment of the second invention of the present application; FIG. 12 is a perspective view of a component unit that constitutes the check valve mechanism of FIG. 11; 13 is an enlarged cross-sectional view of the component unit of FIG. 12; FIG. FIG. 12 is an enlarged cross-sectional view of the ball and seal surface of the check valve mechanism of FIG. 11; FIG. 11 is an enlarged cross-sectional view of a ball and a seal surface of a check valve mechanism according to another example; FIG. 15 is a cross-sectional view showing a method of molding the sealing surface of the check valve mechanism of FIG. 14; FIG. 5 is a cross-sectional view of a check valve component unit according to another embodiment; FIG. 18 is a perspective view of the check valve component unit of FIG. 17; FIG. 4 is a cross-sectional view of a check valve mechanism according to a reference example; FIG. 20 is a perspective view of a component unit that constitutes the check valve mechanism of FIG. 19;

An embodiment of the first invention of the present application will be described below with reference to FIGS.

The electric pump of this embodiment is an electric oil pump that mainly supplies hydraulic pressure to the transmission while the engine is stopped. An electric oil pump draws oil from an oil reservoir at the bottom of the transmission case, discharges the oil, and pumps the oil into the transmission, thereby ensuring the necessary oil pressure and amount of lubricating oil in the transmission.

As shown in FIG. 1, the electric oil pump 1 of this embodiment includes a pump section 2 for generating hydraulic pressure, a motor section 3 for driving the pump section 2, and a controller provided with a control circuit for controlling the motor section 3. 4 (main board), and a housing 5 that accommodates the pump section 2 , the motor section 3 and the controller 4 . Each member or element will be described in detail below.

In the following description, the direction parallel to the axis O of the motor portion 3 is called the "axial direction", and the radial direction of a circle centered on the axis O is called the "radial direction" ("inner diameter direction" and "Outer diameter" also means the inner and outer diameters of the circle). Also, the circumferential direction of a circle centered on the axis O is called the “circumferential direction”.

As shown in FIGS. 1 and 2, the pump section 2 of this embodiment is a rotary pump that pumps oil by rotating. Specifically, the pump unit 2 includes an inner rotor 21 having a plurality of external teeth, an outer rotor 22 having a plurality of internal teeth, and a pump case 23 as a stationary member housing the inner rotor 21 and the outer rotor 22. A trocolloid pump with The inner rotor 21 is arranged on the inner diameter side of the outer rotor 22 . The outer rotor 22 is located eccentrically with respect to the inner rotor 21 . Some of the teeth of the outer rotor 22 mesh with some of the teeth of the inner rotor 21 . If the number of teeth of the inner rotor 21 is n, the number of teeth of the outer rotor 22 is (n+1). Both the outer peripheral surface of the outer rotor 22 and the inner peripheral surface of the pump case 23 are cylindrical surfaces that can be fitted to each other. The outer rotor 22 is rotatably arranged on the inner circumference of the pump case 23 so as to be driven to rotate with the rotation of the inner rotor 21 .

As shown in FIG. 1, the motor section 3 is arranged side by side with the pump section 2 in the axial direction. A three-phase brushless DC motor, for example, is used as the motor unit 3 . The motor section 3 has a stator 30 having a plurality of coils 30 a , a rotor 31 arranged inside the stator 30 with a gap therebetween, and an output shaft 32 coupled to the rotor 31 . The stator 30 is formed with coils 30a corresponding to three phases of U-phase, V-phase and W-phase.

The output shaft 32 is rotatably supported with respect to the housing 5 via

bearings

33 and 34. The inner rotor 21 of the pump section 2 is attached to the end of the output shaft 32 on the pump section 2 side. No speed reducer is arranged between the output shaft 32 and the pump section 2, and the inner rotor 21 is fitted to the output shaft 32 of the motor section 3 so that power can be transmitted by, for example, the width across flats. A seal 35 having a seal lip in sliding contact with the outer peripheral surface of the output shaft 32 is arranged between the bearing 33 located on the axial pump portion 2 side and the inner rotor 21 . This seal 35 prevents oil from leaking from the pump section 2 to the motor section 3 . An axially compressed elastic member 36 is arranged between the bearing 33 and the seal 35 on the axial pump portion 2 side to apply preload to the

bearings

33 and 34 .

A detector 37 is provided between the rotating side and the stationary side of the motor section 3 in order to detect the rotation angle of the rotor 31 in the motor section 3 . The detection unit 37 of this embodiment includes a sensor magnet 37a (for example, a neodymium bond magnet) attached via a bracket 38 to the shaft end of the output shaft 32 on the side opposite to the pump unit, and a housing 5 on the stationary side. It can be configured with a magnetic sensor 37b such as an MR element. The magnetic sensor 37 b is attached to a sub-board 39 that faces the shaft end of the output shaft 32 opposite to the pump and that is arranged in a direction perpendicular to the output shaft 32 . A detected value of the magnetic sensor 37b is input to a control circuit of the controller 4 (main substrate), which will be described later.

A Hall element can also be used as the magnetic sensor 37b. In addition to the magnetic sensor, an optical encoder, resolver, or the like can also be used as the detection unit 37 . It should be noted that the motor section 3 can also be driven sensorless.

The controller 4 of this embodiment is arranged parallel to the output shaft 32 of the motor section 3 . A plurality of electronic components 41 are mounted on the controller 4 . These electronic components 41 constitute a control circuit for controlling the driving of the motor section 3 . In the illustrated example, the controller 4 is arranged with a surface (mounting surface) 40 on which electronic components 41 are mounted facing the pump section 2 and the motor section 3 . Power is supplied to the controller 4 from an external power supply through a connector 42 .

The housing 5 includes a cylindrical housing body 50 with both ends open, a first lid portion 51 that closes the opening of the housing body 50 on the side of the pump in the axial direction, and an opening of the housing body 50 on the side opposite to the pump in the axial direction. and a second lid portion 52 that closes. The first lid portion 51 and the second lid portion 52 are fixed to the housing body 50 using a plurality of fastening bolts B1 and B2, respectively.

The second lid portion 52 has a cylindrical bearing case 52a that supports the bearing 34 on the anti-pump side, and a cover 52b that closes the opening of the bearing case 52a on the anti-pump side. A sub-board 39 is arranged on the inner diameter side of the bearing case 52a. The cover 52b is attached to the bearing case 52a using a fastening member (not shown).

The housing body 50 has a pump accommodating portion 53 that accommodates the pump portion 2, a motor accommodating portion 54 that accommodates the motor portion 3, and a controller accommodating portion 55 that accommodates the controller 4, and is integrally formed in the form of a single component. be. The housing body 50 is formed, for example, by casting, cutting, or a combination thereof. The housing main body 50, the first lid portion 51, and the second lid portion 52 are made of a metal material that is a conductor and has good thermal conductivity, such as an aluminum alloy. Alternatively, one or more of the housing main body 50, the first lid portion 51, and the second lid portion 52 may be made of other metal material (for example, ferrous metal) or resin.

The pump accommodating portion 53 of the housing 5 has a substantially cylindrical shape including the pump case 23 of the pump portion 2 . A pump chamber 66 in which the inner rotor 21 and the outer rotor 22 are accommodated, a suction port 62 and a discharge port 64 are formed in the pump accommodating portion 53 . The suction port 62 and the discharge port 64 are both provided adjacent to the motor section 3 side (the left side in FIG. 1) of the pump chamber 66 and open to the meshing portion of the inner rotor 21 and the outer rotor 22 . As shown in FIG. 2, the suction port 62 and the discharge port 64 are both arc-shaped extending in the circumferential direction of the output shaft 32 and are provided at positions opposed to each other by 180° in the circumferential direction.

The motor accommodating portion 54 of the housing 5 is formed in a cylindrical shape. A stator 30 of the motor portion 3 is press-fitted or adhesively fixed to the cylindrical inner peripheral surface of the motor accommodating portion 54 . The controller accommodating portion 55 of the housing 5 is open on the radially outer diameter side (lower side in FIG. 1), and after the controller 4 is accommodated in the inner circumference, the opening is closed by the cover 57 . The cover 57 is attached to the housing body 50 using the fastening member B3.

As shown in FIGS. 1 and 3, flange-

like mounting portions

58 and 59 for mounting the electric oil pump 1 to a mounting target (transmission case in this embodiment) are integrally formed on both sides in the axial direction of the housing body 50. It is formed. Two fastening holes 58a are formed in the mounting portion 58 on the pump portion 2 side, and two fastening holes 59a are formed in the mounting portion 59 on the anti-pump portion side. By inserting a fastening member (not shown) into these

fastening holes

58a and 59a and screwing the fastening member into the attachment target, the electric oil pump 1 is attached to the attachment target.

As shown in FIGS. 1 and 2, the housing body 50 has a suction pipe 60 through which oil supplied to the pump portion 2 flows, and a discharge pipe 61 through which oil discharged from the pump portion 2 flows. be provided. In this embodiment, both the suction pipe 60 and the discharge pipe 61 are formed linearly. The suction pipe line 60 and the discharge pipe line 61 are configured by, for example, through holes formed in the housing body 50 by machining using a drill or the like. In this case, the inner peripheral surfaces of the suction pipe 60 and the discharge pipe 61 are formed directly on the housing body 50 .

One end of the suction pipe line 60 is connected to the suction port 62 , and one end of the discharge pipe line 61 is connected to the discharge port 64 . The other end of the suction conduit 60 opens to the surface of the housing body 50, and this opening serves as a suction port 63 (see FIG. 3). The other end of the discharge pipe line 61 opens to the surface of the housing body 50 , and this opening serves as a discharge port 65 . The suction port 63 and the discharge port 65 are provided on the surface of the housing 5 that faces the mounting target. As a result, there is no need to route an oil pipe around the electric oil pump 1, and the peripheral structure of the electric oil pump 1 can be simplified.

In this embodiment, as shown in FIG. 4, the discharge pipeline 61 has a small diameter portion 61a and a large diameter portion 61b provided downstream of the small diameter portion 61a. An upstream end of the small diameter portion 61 a communicates with the discharge port 64 . A downstream end portion of the large diameter portion 61 b opens to the surface of the housing body 50 , and this opening serves as a discharge port 65 . The inner peripheral surface of the small diameter portion 61a and the inner peripheral surface of the large diameter portion 61b of the discharge pipe line 61 are connected at a stepped portion 61c. In the illustrated example, the stepped portion 61c has a flat surface 61d perpendicular to the direction of the center line L of the discharge pipe 61 (hereinafter referred to as "flow path direction").

A check valve mechanism 70 is provided in the discharge pipeline 61 . The check valve mechanism 70 has a ball 71, a spring 72 as a biasing member, a holding portion 73 holding the ball 71 and the spring 72, and a seal surface 74, as shown in FIGS. In the illustrated example, a sealing surface 74 is formed on the housing body 50 . Specifically, a seal surface 74 is formed at the inner diameter end of the stepped portion 61 c of the discharge pipe line 61 . In the present embodiment, a chamfered portion is formed on the inner diameter end of the stepped portion 61 c and this chamfered portion functions as a sealing surface 74 . In the illustrated example, the sealing surface 74 is formed of a spherical surface having the same shape as the outer peripheral surface of the ball 71 . In addition, the sealing surface 74 may be configured by a tapered surface having a linear cross section. Further, the chamfered portion may not be formed on the inner diameter end of the stepped portion 61c, and the corner portion formed on this portion may be used as the sealing surface 74. FIG.

The holding portion 73 of this embodiment has a holder 75 and a retaining member 76 . The holder 75 has a guide portion 75a that guides movement of the balls 71 in the direction of the flow path. In the illustrated example, a plurality of (for example, four) guide portions 75a extending in the flow path direction are provided at regular intervals in the circumferential direction. The upstream ends of the plurality of guide portions 75a are connected by a cylindrical portion 75b. A bottom portion 75c is provided near the downstream end of the plurality of guide portions 75a. A through hole is formed in the axial center of the bottom portion 75c. A ball 71 and a spring 72 are arranged on the inner circumference of a plurality of guide portions 75a, and these are held by the guide portion 75a from the outer circumference. The holder 75 is inserted into the inner periphery of the large-diameter portion 61b of the discharge pipe 61 with a gap therebetween. The upstream end of the holder 75 is in contact with the stepped portion 61 c of the discharge pipe line 61 . In this state, the ball 71 contacts the seal surface 74 (inner diameter end of the stepped portion 61c), and the spring 72 is arranged between the ball 71 and the bottom portion 75c of the holder 75 in a compressed state.

The retaining member 76 has a ring shape and is fixed to the large-diameter portion 61b of the discharge pipe 61 by appropriate means such as press-fitting or screwing. The holder 75 is fixed to the housing body 50 by sandwiching the holder 75 from both sides in the direction of the flow path between the retainer member 76 and the stepped portion 61c of the discharge pipe line 61 . In the illustrated example, the retaining member 76 is fixed at a position retracted upstream of the surface 50 a of the housing body 50 . As a result, the check valve mechanism 70 is completely accommodated inside the housing main body 50, so interference with other members can be avoided. Note that the retaining member 76 may be a retaining ring. In this case, an annular groove is formed in the inner peripheral surface of the large-diameter portion 61b of the discharge pipe line 61, and a retaining ring (retaining member) is attached to the annular groove (not shown).

The ball 71 is made of a material harder than the sealing surface 74 (housing body 50), such as a ferrous metal, specifically carbon steel, especially stainless steel. The spring 72 is made of ferrous metal such as stainless steel. The holder 75 is preferably made of resin from the viewpoint of formability, but may be made of iron-based or aluminum-based metal. The retaining member 76 is made of iron-based or aluminum-based metal. When the retainer member 76 is used as a positioning reference, which will be described later, it is preferable to use an iron-based material from the viewpoint of strength. When the retainer member 76 is press-fitted into the housing body 50 , the retainer member 76 is preferably made of the same metal material as the housing body 50 . As a result, the coefficients of linear expansion of both are close to each other or have the same value, so that the retaining member 76 can be prevented from coming off from the housing main body 50 due to temperature changes.

In the electric oil pump 1 having the above configuration, when the motor portion 3 is stopped, the ball 71 is pressed against the seal surface 74 by the biasing force of the spring 72, and the discharge pipe line 61 is closed. In this state, if the oil flows back from the transmission side, the ball 71 is further pressed against the seal surface 74, so that the discharge line 61 is kept closed. As a result, the inflow of reversed oil into the pump section 2 is restricted, and failure of the motor section 3 and the controller 4 due to the reverse rotation of the pump section 2 can be prevented.

When the motor portion 3 is driven, the inner rotor 21 rotates, and the outer rotor 22 meshing with it rotates, so that the space formed between the teeth of both expands and contracts along with the rotation. As a result, the oil accumulated in the oil sump inside the transmission case is sucked into the pump portion 2 through the suction pipe line 60 , compressed by the pump portion 2 and discharged to the discharge pipe line 61 .

4, the ball 71 of the check valve mechanism 70 is pushed downstream while compressing the spring 72 by the hydraulic pressure of the discharge pipe 61, and the ball 71 separates from the sealing surface 74 to discharge. Line 61 is opened. As a result, the oil flows around the outer periphery of the ball 71 (the space between the plurality of guide portions 75a) and the outer periphery of the bottom portion 75c of the holder 75, passes through the through hole of the retaining member 76, and is discharged from the discharge port 65 (dotted line arrow A), is supplied to the transmission. Since most of the oil flowing through the discharge pipe line 61 wraps around the outer circumference of the bottom portion 75c of the holder 75, little oil passes through the through hole provided in the axial center of the bottom portion 75c. Therefore, the through hole in the bottom portion 75c may be omitted if it is not particularly necessary.

In the check valve mechanism 70 described above, as shown in FIG. 6, it is preferable to set the contact angle α between the ball 71 and the seal surface 74 to 20° or more. This is because if the contact angle α is too small, the ball 71 may get caught in the seal surface 74 and become difficult to separate from the seal surface 74 (see FIG. 10). Also, the contact angle α between the ball 71 and the seal surface 74 is preferably set to 120° or less. This is because if the contact angle α is too large, the sealing performance becomes poor. The contact angle α is the angle formed by the tangential line of the outer peripheral surface of the ball 71 at the contact portion between the ball 71 and the seal surface 74 in the section including the center line L of the discharge pipe 61 (see FIG. 6). When the ball 71 and the seal surface 74 are in contact with each other as in the present embodiment, the angle formed by the tangent line of the outer peripheral surface of the ball 71 at the center of the contact portion of the arc-shaped cross section between the ball 71 and the seal surface 74 is is the contact angle α.

When assembling the check valve mechanism 70 to the housing main body 50, the ball 71, the spring 72, and the holder 75 are inserted from the discharge port 65 into the large diameter portion 61b of the discharge pipe line 61 in this order. In this embodiment, the outer diameter of the holder 75 is slightly smaller than the inner diameter of the large diameter portion 61b, so the holder 75 can be easily inserted into the inner circumference of the large diameter portion 61b through a gap. After that, the retaining member 76 is fixed to the opening (discharge port 65) of the discharge pipe line 61 by press-fitting, screwing, or the like. The retaining member 76 fixed to the discharge pipe line 61 contacts the holder 75 from the downstream side, thereby restricting the holder 75 from coming off the discharge pipe line 61 . In this state, the ball 71 contacts the seal surface 74, and the spring 72 is held between the ball 71 and the bottom portion 75c of the holder 75 in a compressed state. That is, the ball 71 is pressed against the sealing surface 74 by the elastic force of the spring 72 .

In this embodiment, as shown in FIG. 5, the holder 75 and the retaining member 76 are engaged in the circumferential direction of the discharge pipe line 61. Specifically, a concave portion 76a is formed in the end face on the upstream side of the retaining member 76, and the engaging portion 75d of the holder 75 (the lower end of the guide portion 75a in the illustrated example) is fitted into this concave portion 76a. Circumferential engagement between the recess 76a and the engaging portion 75d restricts the rotation of the holder 75 in the discharge pipe 61, so that the ball 71 and the spring 72 can be stably held and the holder Wear of 75 can be prevented.

The sealing surface 74 is formed, for example, by the following procedure. First, as shown in FIG. 7, the housing body 50 is machined (eg, turned) to form a discharge pipe line 61 having a small-diameter portion 61a, a large-diameter portion 61b, and a step portion 61c. At this time, a flat surface 61d is formed over the entire area of the stepped portion 61c, and a right-angled corner portion 61e is formed at the inner diameter end of the stepped portion 61c. Then, a ball 71 is brought into contact with the corner portion 61e from the downstream side and pushed upstream as indicated by the dotted line to plastically deform the corner portion 61e. In this case, it is preferable to press the ball 71 against the corner portion 61e with a pressure (load) higher than the pressure generated by the backflow of oil from the transmission side. Specifically, when the projected area of the ball 71 in the flow direction is S, the pressure at the time of oil backflow is P, and the safety factor is c, the load F pressing the ball 71 satisfies F>S.P.c. should be set to

The sealing surface 74 formed by the ball 71 in this way is a plastically worked surface consisting of a spherical surface having the same shape as the ball 71 . As a result, the adhesion between the seal surface 74 and the ball 71 is enhanced, and the sealing performance is improved. Instead of the ball 71, the sealing surface 74 can be formed by pressing a jig having a spherical molding surface of the same shape as the ball 71 against the corner 61e of the discharge pipe line 61. FIG. Alternatively, the sealing surface 74 may be formed by machining such as cutting. In this case, the sealing surface 74 is not limited to a spherical surface, and may be of any shape such as a tapered surface. When the pressure of the oil flowing back from the transmission is low, the corner 61e of the discharge pipe line 61 may be left and the corner 61e may function as a sealing surface.

In this embodiment, as described above, the discharge pipe line 61 is provided with the large-diameter portion 61b for disposing the holding portion 73 of the check valve mechanism 70 . In this case, even if the discharge pipe 61 is not provided with the check valve mechanism 70 , the large-diameter portion 61 b of the discharge pipe 61 does not hinder the function of the electric oil pump 1 . Therefore, the common housing main body 50 can be used regardless of whether the check valve mechanism 70 is provided or not, thereby reducing costs.

In the electric oil pump 1 described above, the suction port 63 and the discharge port 65 are provided on the surface of the housing body 50 . In addition, a suction line 60 connecting the suction port 63 and the pump section 2 and a discharge line 61 connecting the discharge port 65 and the pump section 2 are both provided in the housing body 50 . Therefore, the housing main body 50 can be cooled by the oil flowing through the suction pipe 60 and the discharge pipe 61 . This cooling effect can accelerate the cooling of the motor unit 3 and the controller 4 that serve as heat sources, and the reliability of the electric oil pump 1 can be enhanced. In addition, the size of the electric oil pump 1 can be reduced as compared with the case where the suction pipe 60 and the discharge pipe 61 are provided in a member separate from the housing main body 50 .

In this embodiment, the suction pipe line 60 and the discharge pipe line 61 are arranged in the region between the pump section 2 and the motor section 3 in the axial direction. More specifically, as shown in FIG. 1 , the suction line 60 and the discharge line 61 are arranged in the region between the pump portion 2 and the seal 35 in the axial direction. Therefore, the installation space for the suction pipe 60 and the discharge pipe 61 can be secured without interfering with the parts housed inside the housing 5 .

It is also possible to use the suction line 60 as the discharge line and the discharge line 61 as the suction line without changing the configurations of the suction line 60 and the discharge line 61 . Both the suction pipe 60 and the discharge pipe 61 are arranged in the region between the pump section 2 and the motor section 3 in the axial direction. ) can also be placed in

The present invention is not limited to the above embodiments. Other embodiments of the present invention will be described below, but overlapping descriptions of the same points as those of the above-described embodiments will be omitted.

The embodiment shown in FIG. 8 differs from the above embodiment in that the downstream end of the holding portion 73 of the check valve mechanism 70 protrudes from the discharge port 65 of the housing body 50 . Specifically, part of the retaining member 76 of the holding portion 73 protrudes from the surface 50 a of the housing body 50 . This projecting portion Q can be used, for example, as a positioning reference when mounting the housing 5 to the transmission case.

In this embodiment, a gap G is formed between the upstream end of the holding portion 73 and the stepped portion 61c of the discharge pipe line 61 in the flow direction. Therefore, by pushing the holding portion 73 (the holder 75 and the retaining member 76) further upstream, the holding portion 73 can be completely accommodated inside the housing body 50 (inside the discharge pipe line 61). Specifically, the size δ2 of the gap G between the upstream end of the holding portion 73 and the step portion 61c of the discharge pipe line 61 is larger than the projection amount δ1 of the projecting portion Q of the holding portion 73 . According to this configuration, the holding portion 73 can be disposed either at a position protruding from the discharge port 65 of the housing body 50 or at a position retracted upstream of the surface 50 a of the housing body 50 . , a protruding portion Q can be provided selectively.

The embodiment shown in FIG. 9 differs from the above embodiment in that a seal surface 74 is provided on a holder 75 . Specifically, the upstream end of the holder 75 is provided with an inner-diameter protruding portion 75e, and the sealing surface 74 is formed on the protruding portion 75e. In this case, the bottom portion 75c of the holder 75 is formed separately from the guide portion 75a. Specifically, a concave portion 75f is formed on the inner peripheral surface of the guide portion 75a, and a ring-shaped or C-shaped bottom portion 75c is fitted in the concave portion 75f. In this case, the check valve mechanism 70 is assembled by inserting the ball 71 and the spring 72 from the opening at the downstream end of the holder 75 and then mounting the bottom portion 75c in the recess 75f of the guide portion 75a. In the illustrated example, the outer peripheral surface of the holder 75 and the large diameter portion 61b of the discharge pipe line 61 are fitted with a gap, but the outer peripheral surface of the holder 75 and the large diameter portion 61b of the discharge pipe line 61 are fitted together with a gap therebetween. is press-fitted, and the upstream end face of the holder 75 is brought into close contact with the stepped portion 61c of the discharge pipe line 61 along the entire periphery, thereby reliably preventing oil leakage from between the holder 75 and the stepped portion 61c. may

The present invention is applicable not only to electric oil pumps that pump oil, but also to electric pumps that pump liquids other than oil.

Next, an embodiment of the second invention of the present application will be described based on FIGS. Since the basic configuration of the electric oil pump is the same as that described above, FIGS.

A check valve mechanism 70 according to an embodiment of the second invention of the present application is provided in the discharge pipeline 61 as shown in FIGS. The check valve mechanism 70 has a ball 71 , a spring 72 as a biasing member, a holding portion 73 that holds the ball 71 and the spring 72 , and a seal surface 74 . In the illustrated example, a sealing surface 74 is formed on the housing body 50 . Specifically, a seal surface 74 is formed at the inner diameter end of the stepped portion 61 c of the discharge pipe line 61 . In the present embodiment, a chamfered portion is formed on the inner diameter end of the stepped portion 61 c and this chamfered portion functions as a sealing surface 74 . In the illustrated example, the sealing surface 74 is formed of a spherical surface having the same shape as the outer peripheral surface of the ball 71 . In addition, the sealing surface 74 may be configured by a tapered surface having a linear cross section. Further, the chamfered portion may not be formed on the inner diameter end of the stepped portion 61c, and the corner portion formed on this portion may be used as the sealing surface 74. FIG.

The holding portion 73 of this embodiment has a holder 75 and a retaining member 76 . The holder 75 has a guide portion 75a that guides movement of the balls 71 in the direction of the flow path. In the illustrated example, a plurality of (for example, four) guide portions 75a extending in the flow path direction are provided at regular intervals in the circumferential direction. The upstream ends of the plurality of guide portions 75a are connected by a cylindrical portion 75b. In the illustrated example, the upstream end of the guide portion 75a protrudes further upstream than the cylindrical portion 75b. A circumferential interval between the adjacent guide portions 75 a is smaller than the diameter D 2 of the ball 71 and the outer diameter D 3 of the spring 72 . The inner diameter surface of each guide portion 75a is inclined so as to be slightly displaced toward the outer diameter side toward the upstream side. That is, the distance between the guide portions 75a that face each other in the diametrical direction of the discharge pipe 61 increases toward the upstream side.

The holder 75 has a bottom portion 75c as a support portion that supports the spring 72 from the downstream side. The bottom portion 75c is provided near the downstream ends of the plurality of guide portions 75a. The bottom portion 75c has a substantially disc shape, and a through hole is formed in the center of the bottom portion 75c. A ball 71 and a spring 72 are arranged on the inner circumference of a plurality of guide portions 75a, and these are held by the guide portion 75a from the outer circumference. The holder 75 is inserted into the inner periphery of the large-diameter portion 61b of the discharge pipe 61 with a gap therebetween. The upstream end of the holder 75 is in contact with the stepped portion 61 c of the discharge pipe line 61 . In this state, the ball 71 contacts the seal surface 74 (inner diameter end of the stepped portion 61c), and the spring 72 is arranged between the ball 71 and the bottom portion 75c of the holder 75 in a compressed state.

The holding portion 73 is provided with a locking portion that restricts the ball 71 from jumping out. In this embodiment, as shown in an enlarged view in FIG. 13, an engaging portion 77 projecting radially inward is provided at the upstream end of the holder 75 . The locking portion 77 is provided at the upstream end of each guide portion 75a of the holder 75, and as a result, the locking portion 77 is provided at a plurality of locations (four locations in the illustrated example) spaced apart in the circumferential direction. The inner diameter D1 of the engaging portion 77 (the diameter of the circle passing through the inner diameter end of each engaging portion 77) is slightly smaller than the diameter D2 of the ball 71 and slightly larger than the outer diameter D3 of the spring 72. The locking portion 77 is integrally injection molded with the holder 75 from resin. At this time, the engaging portion 77 becomes an undercut, but it can be formed by so-called "forcible extraction" in which the molded product (near the engaging portion 77) is released from the mold while being elastically deformed.

The retaining member 76 has a ring shape and is fixed to the large-diameter portion 61b of the discharge pipe 61 by appropriate means such as press-fitting or screwing (see FIG. 4). The holder 75 is fixed to the housing body 50 by sandwiching the holder 75 from both sides in the direction of the flow path between the retainer member 76 and the stepped portion 61c of the discharge pipe line 61 . In the illustrated example, the retaining member 76 is fixed at a position retracted upstream of the surface 50 a of the housing body 50 . As a result, the check valve mechanism 70 is completely accommodated inside the housing main body 50, so interference with other members can be avoided. Note that the retaining member 76 may be a retaining ring. In this case, an annular groove is formed in the inner peripheral surface of the large-diameter portion 61b of the discharge pipe line 61, and a retaining ring (retaining member) is attached to the annular groove (not shown).

In the electric oil pump 1 having the above configuration, when the motor portion 3 is stopped, the ball 71 is pressed against the seal surface 74 by the biasing force of the spring 72, and the discharge pipe line 61 is closed. In this state, if the oil flows back from the transmission side, the ball 71 is further pressed against the seal surface 74, so that the discharge line 61 is kept closed. As a result, the inflow of reversed oil into the pump portion 2 is restricted, and failure of the motor portion 3 due to the reverse rotation of the pump portion 2 can be prevented.

11, the ball 71 of the check valve mechanism 70 is pushed downstream while compressing the spring 72 by the hydraulic pressure of the discharge pipe 61, and the ball 71 separates from the sealing surface 74 to discharge. Line 61 is opened. As a result, the oil flows around the outer periphery of the ball 71 (the space between the plurality of guide portions 75a) and the outer periphery of the bottom portion 75c of the holder 75, passes through the through hole of the retaining member 76, and is discharged from the discharge port 65 (dotted line arrow A), is supplied to the transmission. Since most of the oil flowing through the discharge pipe line 61 wraps around the outer circumference of the bottom portion 75c of the holder 75, little oil passes through the through hole provided in the axial center of the bottom portion 75c. Therefore, the through hole in the bottom portion 75c may be omitted if it is not particularly necessary.

In the check valve mechanism 70 described above, as shown in FIG. 14, it is preferable to set the contact angle α between the ball 71 and the seal surface 74 to 20° or more. This is because if the contact angle α is too small as shown in FIG. Also, the contact angle α between the ball 71 and the seal surface 74 is preferably set to 120° or less. This is because if the contact angle α is too large, the sealing performance becomes poor. The contact angle α is the angle formed by the tangential line of the outer peripheral surface of the ball 71 at the contact portion between the ball 71 and the seal surface 74 in the cross section (see 14) including the center line L of the discharge pipe 61 . When the ball 71 and the seal surface 74 are in contact with each other as shown in FIG. Let the angle be α.

When assembling the check valve mechanism 70 to the housing body 50, first, the spring 72 and the ball 71 are accommodated in the inner periphery of the holder 75 of the holding portion 73. As shown in FIG. Specifically, first, the spring 72 is inserted from the opening on the upstream side of the holder 75 . At this time, the opening diameter of the holder 75 on the upstream side, that is, the inner diameter D1 of the locking portion 77 is slightly larger than the outer diameter D3 of the spring 72 (see FIG. 13), so that the spring 72 interferes with the locking portion 77. can be inserted into the inner periphery of the holder 75 without

After that, the ball 71 is inserted through the opening on the upstream side of the holder 75 . At this time, since the diameter of the opening of the holder 75, that is, the inner diameter D1 of the locking portion 77 is slightly smaller than the diameter D2 of the ball 71, the locking portion 77 prevents the ball 71 from being inserted into the inner circumference of the holder 75. be done. Therefore, by pushing the ball 71 into the inner periphery of the locking portion 77, the periphery of the locking portion 77 (specifically, the portion of the guide portion 75a that protrudes upward from the cylindrical portion 75b) is moved to the outer diameter side. The inner diameter of the engaging portion 77 is widened by elastic deformation. In the present embodiment, the locking portions 77 are not annular, but are provided at a plurality of locations spaced apart in the circumferential direction, so that they can be easily displaced radially by the pressing force of the balls 71 . As a result, the ball 71 can pass downstream beyond the locking portion 77 , and the ball 71 is arranged on the inner circumference of the holder 75 . Thus, a check valve component unit 78 is formed in which the ball 71 and the spring 72 are arranged on the inner periphery of the holder 75 (see FIG. 12).

In the check valve component unit 78, the locking portion 77 is engaged with the ball 71 from the upstream side, thereby restricting the ball 71 from jumping out of the opening of the holder 75 on the upstream side. Also, the spring 72 is supported by the bottom portion 75 c of the holder 75 . As described above, the ball 71 and the spring 72 are prevented from falling off from the inner periphery of the holder 75 , so that the check valve component unit 78 in which these are integrated can be easily assembled to the housing body 50 .

At this time, the engaging portion 77 is adjusted so that the force (ball removal resistance) that restricts the movement of the ball 71 to the upstream side by the engaging portion 77 is greater than the force that presses the ball 71 against the engaging portion 77 by the spring 72 . An inner diameter D1 of 77 (that is, an engagement margin between locking portion 77 and ball 71) is set. On the other hand, if the inner diameter D1 of the locking portion 77 is too small (that is, if the engagement margin between the locking portion 77 and the ball 71 is too large), the holder 75 cannot be elastically deformed and the ball 71 cannot be pushed. As described above, the inner diameter D1 of the locking portion 77 is set to, for example, 90% or more and 98% or less of the diameter D2 of the ball 71 .

Then, the check valve component unit 78 is inserted into the large diameter portion 61b of the discharge pipe line 61 from the discharge port 65 . In this embodiment, the outer diameter of the holder 75 is slightly smaller than the inner diameter of the large diameter portion 61b, so the holder 75 can be easily inserted into the inner circumference of the large diameter portion 61b through a gap. After that, the retaining member 76 is fixed to the opening (discharge port 65) of the discharge pipe line 61 by press-fitting, screwing, or the like. The retaining member 76 fixed to the discharge pipe line 61 contacts the holder 75 from the downstream side, thereby restricting the holder 75 from coming off the discharge pipe line 61 . In this state, the ball 71 contacts the seal surface 74, and the spring 72 is held between the ball 71 and the bottom portion 75c of the holder 75 in a compressed state. That is, the ball 71 is pressed against the sealing surface 74 by the elastic force of the spring 72 . At this time, the ball 71 and the engaging portion 77 are separated from each other in the flow path direction. Thus, after the check valve component unit 78 is incorporated into the discharge pipe line 61 , the ball 71 is locked by the sealing surface 74 , so the ball 71 does not come off the holder 75 .

In this embodiment, as shown in FIG. 11, the holder 75 and the retaining member 76 are engaged in the circumferential direction of the discharge pipe line 61. Specifically, a concave portion 76a is formed in the end face on the upstream side of the retaining member 76, and the engaging portion 75d of the holder 75 (the lower end of the guide portion 75a in the illustrated example) is fitted into this concave portion 76a. Circumferential engagement between the recess 76a and the engaging portion 75d restricts the rotation of the holder 75 in the discharge pipe 61, so that the ball 71 and the spring 72 can be stably held and the holder Wear of 75 can be prevented.

The sealing surface 74 is formed, for example, by the following procedure. First, as shown in FIG. 16, the housing body 50 is machined (eg, turned) to form a discharge pipe line 61 having a small-diameter portion 61a, a large-diameter portion 61b, and a stepped portion 61c. At this time, a flat surface 61d is formed over the entire area of the stepped portion 61c, and a right-angled corner portion 61e is formed at the inner diameter end of the stepped portion 61c. Then, a ball 71 is brought into contact with the corner portion 61e from the downstream side and pushed upstream as indicated by the dotted line to plastically deform the corner portion 61e. In this case, it is preferable to press the ball 71 against the corner portion 61e with a pressure (load) higher than the pressure generated by the backflow of oil from the transmission side. Specifically, when the projected area of the ball 71 in the flow direction is S, the pressure at the time of oil backflow is P, and the safety factor is c, the load F pressing the ball 71 satisfies F>S.P.c. should be set to

In the embodiment shown in FIGS. 17 and 18, a retaining member 76 is fixed to a holder 75, and a ball 71, a spring 72, a holder 75, and a retaining member 76 constitute a check valve component unit 78. Specifically, in the guide portion 75a of the holder 75, a concave portion is provided in the outer peripheral surface of the protruding portion 75f that protrudes downstream from the bottom portion 75c, and the annular retaining member 76 is fixed to this concave portion. In the illustrated example, an engaging claw 75g protruding radially outward is provided at the downstream end of the outer peripheral surface of the projecting portion 75f. An engagement concave portion 76 b is provided at the downstream end of the inner peripheral surface of the retainer member 76 . By fitting the engaging claws 75g of the holder 75 into the engaging recesses 76b of the retaining member 76, the engaging claws 75g engage with the retaining member 76 from the downstream side. Exit from is restricted.

In this embodiment, by pushing the retaining member 76 from the downstream side of the holder 75, the projecting portion 75f of the downstream end of the holder 75 is elastically deformed to the inner diameter side, and the outer diameter of the engaging claw 75g (the engaging claw 75g diameter of a circle passing through the outer diameter end of At this time, since the engaging claws 75g are not annular but are provided at a plurality of locations spaced apart in the circumferential direction, they are easily elastically deformed by the pushing force of the retaining member 76 . After the engaging claw 75g and the engaging recess 76b of the retaining member 76 are fitted, the retaining member 76 is attached to the holder 75 by elastically restoring the engaging claw 75g.

By holding the check valve component unit 78, inserting the holder 75 into the large diameter portion 61b of the discharge pipe 61, and fixing (pressing) the retaining member 76 into the large diameter portion 61b, the check valve component unit 78 is held. A valve component unit 78 is attached to the housing body 50 . In the illustrated example, since the retaining member 76 is fixed to the outer periphery of the holder 75 , the outer peripheral surface of the retaining member 76 can be press-fitted into the inner peripheral surface of the large diameter portion 61 b of the discharge pipe 61 . As described above, according to the configuration of this embodiment, the check valve mechanism 70 is provided in the housing body 50 by one operation of inserting and fixing the check valve part unit 78 into the large diameter portion 61b of the discharge pipe 61. be able to.

Further, in this embodiment, the holder 75 is provided with a contact portion 79 that defines the downstream end position of the ball 71 . In the illustrated example, the contact portion 79 has a columnar shape extending upstream from the bottom portion 75 c of the holder 75 . The contact portion 79 is inserted into the inner circumference of the spring 72 . When the electric oil pump 1 is driven and the ball 71 is pushed down by the pressure of the discharge pipe 61 , the ball 71 comes into contact with the contact portion 79 . This restricts the movement of the ball 71 to the downstream side more than necessary, so that the ball 71 can be stably held.

1 electric oil pump (electric pump)
2 pump section 3 motor section 4 controller 5 housing 50 housing main body 60 suction pipe line 61 discharge pipe line 61 a small diameter portion 61 b large diameter portion 61 c stepped portion 61 d flat surface 62 suction port 63 suction port 64 discharge port 65 discharge port 66 pump chamber 70 Check valve mechanism 71 Ball 72 Spring (biasing member)
73 holding portion 74 sealing surface 75 holder 76 retaining member

Claims

a motor portion, a pump portion driven by the motor portion, a housing that accommodates the motor portion and the pump portion, an intake port and a discharge port formed on a surface of the housing, the intake port and the pump portion an electric pump, comprising: a suction line communicating with the discharge port; a discharge line connecting the discharge port and the pump section; and a check valve mechanism provided in the discharge line.
2. The method according to claim 1, wherein the check valve mechanism comprises a ball, a sealing surface, a biasing member that presses the ball against the sealing surface, and a retaining portion that retains the ball and the biasing member on an inner circumference. Electric pump as described.
The electric pump according to claim 2, wherein the contact angle between the ball and the seal surface is 20° or more.
4. The holding portion can be disposed either at a position where a portion of the holding portion protrudes from the discharge port of the housing or at a position where the holding portion is retracted upstream from the surface of the housing. Electric pump as described in paragraph.
the holding part has a holder and a retaining member,
The holder has the ball and the biasing member arranged on the inner circumference thereof, and is inserted into the inner circumference of the discharge pipe with a gap therebetween,
3. The electric pump according to claim 2, wherein the retaining member is fixed to the discharge pipe and abuts the holder from the downstream side.
The electric pump according to claim 5, wherein the holder and the retainer are engaged in the circumferential direction of the discharge pipe.
wherein the housing comprises a housing body integrally formed as one piece and housing the motor section and the pump section;
The electric pump according to any one of claims 1 to 6, wherein the housing body is formed with the discharge conduit.
the discharge conduit has a small diameter portion and a large diameter portion;
The electric pump according to claim 7, wherein the holding portion is arranged on the large diameter portion.
The electric pump according to claim 7, wherein the sealing surface is formed on the housing body.
The discharge pipeline has a small diameter portion, a large diameter portion, and a stepped portion connecting the inner peripheral surface of the small diameter portion and the inner peripheral surface of the large diameter portion,
10. The electric pump according to claim 9, wherein the sealing surface is formed on the stepped portion.
The electric pump according to claim 9 or 10, wherein the sealing surface is a plastically worked surface having the same shape as the outer peripheral surface of the ball.
The electric pump according to any one of claims 1 to 11, wherein the discharge pipe line is arranged in an axially inter-regional region between the motor section and the pump section.
The electric pump according to any one of claims 1 to 12, wherein the pump section is a rotary pump that pumps liquid by rotating.
A check valve mechanism comprising a seal surface, a ball, a biasing member that biases the ball upstream and presses it against the seal surface, and a holder that holds the ball and the biasing member on the inner circumference There is
A check valve mechanism in which the holder has a support portion that supports the biasing member from the downstream side and a locking portion that can be engaged with the ball from the upstream side.
A check valve part unit comprising a ball, a biasing member that biases the ball upstream, and a holder that holds the ball and the biasing member on an inner circumference,
The check valve part unit, wherein the holder has a support portion that supports the biasing member from the downstream side and a locking portion that can be engaged with the ball from the upstream side.