JP5141956B2 - Electric pump - Google Patents

Description

  The present invention is rotatably supported by a housing that houses an annular coil portion, an outer rotor portion that is driven to rotate inside the housing based on the magnetic field of the coil portion, and a support shaft portion that is eccentric with respect to the outer rotor portion. And an inner rotor having an outer peripheral surface that engages with an inner peripheral surface of the outer rotor portion, and sucks / discharges fluid based on a displacement of a space formed between the outer rotor portion and the inner rotor by rotational driving of the outer rotor portion. It relates to an electric pump.

  There exists patent document 1 shown below as prior art document information relevant to this kind of electric pump. The housing of the electric pump described in Patent Document 1 includes a rear casing that rotatably accommodates an inner rotor and an outer rotor portion, and a front casing that closes an open end portion of the rear casing in a liquid-tight manner. These back casing and front casing are made of synthetic resin and are joined to each other by welding. The support shaft that supports the inner rotor includes a large-diameter bearing portion that guides and guides the inner rotor, and a pair of supported portions that extend from both ends of the bearing portion. One of these supported portions is closely fitted in a recess formed on the inner surface of the back casing, and the other supported portion is closely fitted in a recess formed on the inner surface of the front casing.

JP 2006-336469 A (paragraph numbers 0026 and 0027, FIG. 1)

  In the electric pump described in Patent Document 1, as described above, it is necessary to provide a recess for closely fitting the support shaft in both the resin-made rear casing and the front casing constituting the housing. It was. As a result, it is difficult to reduce the manufacturing cost of the electric pump because it is necessary to provide recesses for close fitting in both casings with high positional accuracy and to design / mold the inlays and welds between the casings with high accuracy. It was. In addition, the external dimensions in the axial direction of the housing tend to be large, which has been a factor that hinders the compactness of the electric pump.

  Accordingly, an object of the present invention is to provide an electric pump that can be easily made more compact and to provide an electric pump that can be manufactured at a lower cost in view of the drawbacks of the electric pump according to the prior art exemplified above. There is.

A first characteristic configuration of the present invention includes a housing that houses an annular coil portion;
An outer rotor portion that is driven to rotate based on the magnetic field of the coil portion inside the housing;
An inner rotor that is rotatably supported by a support shaft portion that is eccentric with respect to the outer rotor portion and has an outer peripheral surface that engages with an inner peripheral surface of the outer rotor portion;
Inhale / discharge fluid based on the displacement of the space formed between the outer rotor portion and the inner rotor due to the rotational drive of the outer rotor portion,
The support shaft portion includes a first end supported by the housing;
The outer rotor portion includes a pair of end surfaces that are opposed and guided so as to be sandwiched from the axial direction by the housing and the second end of the support shaft portion ,
A flange-shaped side plate portion provided at the second end of the support shaft portion and having an end surface facing the end surface of the outer rotor portion in the axial direction;
A hole formed through the side plate portion and communicating with a space formed between the housing and the side plate portion and a space formed between the outer rotor portion and the inner rotor. .

  Therefore, in the electric pump according to the first characteristic configuration of the present invention, the support shaft portion has a substantially cantilever structure, and the end portion of the support shaft portion is fitted to only one of the pair of housings of the housing. As a result, it is easy to assemble. Further, since the fitting recess for the support shaft portion only needs to be provided on one side of the pair of housings constituting the housing, the influence of the manufacturing error of the housing hardly occurs, and the design and structure of the member are simple. Just do it. Further, since the fitting recess only needs to be provided in one housing, the outer dimension of the housing in the axial direction can be reduced, and the electric pump can be easily made compact. In addition, the problem of the swinging of the supporting shaft part in use and each rotor, which is concerned by having the supporting shaft part substantially cantilevered in this way, is that the outer rotor part is the first of the housing and the supporting shaft part. Since the pair of end surfaces are provided to be opposed and guided in the axial direction by the two ends, the second end of the support shaft portion is opposed and guided by the outer rotor portion, and the outer rotor portion is sufficiently guided and opposed by the housing.

  In addition, here, the two members having surfaces facing each other are opposed to each other, and at least in a normal operation state, do not directly touch each other, and maintain an adjacent state with a thin oil film interposed therebetween, In addition, if one member tries to swing from the original rotation axis by the action of some external force or the like, it indicates a relationship that can be corrected to the original posture by directly supporting the other member.

Also, with this configuration, the outer rotor portion is a generally cylindrical member, and the outer rotor portion is guided and opposed by the outer rotor portion in the vicinity of the outermost periphery of the side plate portion, thereby effectively suppressing the shake of the outer rotor portion. it can.

  Another feature of the present invention is that the housing is provided with an opposing inner peripheral surface that guides and guides a part of the outer peripheral surface of the outer rotor portion in the radial direction.

  With this configuration, even if the outer rotor portion is a general generally cylindrical member, the outer peripheral portion on the proximal end side of the cylindrical member is opposed and guided in the radial direction by the opposing inner peripheral surface provided in the housing. be able to. As a result, the deflection of the outer rotor portion with respect to the shaft core of the housing is suppressed.

  Another feature of the present invention is that the housing is provided with an opposing outer peripheral surface that guides and guides a part of the inner peripheral surface of the outer rotor portion in the radial direction.

  With this configuration, even if the outer rotor portion is a general cylindrical member, the inner peripheral portion on the proximal end side of the cylindrical member is guided in the radial direction by the opposing outer peripheral surface provided in the housing. be able to. As a result, the deflection of the outer rotor portion with respect to the axis of the housing is further suppressed.

  According to another characteristic configuration of the present invention, the housing has a base housing portion that supports the first end portion of the support shaft portion, and an annular shape that is attached to the base housing portion so as to accommodate the coil portion. A housing portion, and one end face of the outer rotor portion is oppositely guided in an axial direction by an end face formed in the base housing portion.

  If it is this structure, the function which guides an outer rotor part oppositely can be ensured exclusively in a base housing | casing part, and it is not necessary to provide an opposing guide part in a cyclic | annular housing | casing part annular | circular housing part. Therefore, even if it is appropriate that the base casing is made of metal for durability, the annular casing can be made of resin that can be manufactured at low cost.

The best mode for carrying out the present invention will be described below with reference to the drawings.
The electric pump 50 shown in FIGS. 1, 3, and 4 mainly includes a housing 1 that houses an annular coil portion 6, a support shaft portion 7 that is supported by a base housing portion 2 that constitutes the housing 1, and The rotor portion is driven to rotate inside the housing 1. The rotor portion includes an outer rotor portion 10 that is rotationally driven based on a change in the magnetic field of the coil portion 6, and an inner rotor 15 that is rotationally driven by engagement with the outer rotor body 11, and has a trochoidal shape formed on both rotors. The teeth cooperate to constitute a trochoid pump that sucks / discharges oil as a fluid.

  The housing 1 is welded to the metallic base casing 2, the synthetic resin annular casing 4 screwed onto the outer periphery of the boss 3 of the base casing 2, and the annular casing 4. It also comprises a cover housing portion 5 made of synthetic resin. The coil unit 6 is housed in the annular housing unit 4. Hereinafter, the base housing portion 2 side is referred to as a base end side in the electric pump, and the cover housing portion 5 side is referred to as a distal end side in the electric pump with the annular housing portion 4 as a reference. A suction space 18 and a discharge space 19 are formed in the boss portion 3 of the base housing portion 2 so as to be spaced apart from each other, and a suction port communicating with each space is provided at the most proximal end side of the base housing portion 2. 18a and discharge port 19a are opened separately.

A wall member 4a that isolates the region of the trochoid pump from the outside is integrally formed on the distal end side of the annular housing portion 4. A control board 20 is attached to the outer surface of the wall member 4 a and is isolated from the outside by the cover housing unit 5.
The support shaft portion 7 includes a support shaft 8 supported by the base housing portion 2 and a flange-shaped side plate 9 (an example of a side plate portion) fixed to the tip of the support shaft 8.

  The outer rotor portion 10 is fixed to the outer periphery of the back yoke 12, a cylindrical outer rotor body 11 having trochoidal inner teeth, a back yoke 12 made of a ferromagnetic material such as iron fixed to the outer periphery of the outer rotor body 11, and The cylindrical permanent magnet 13 is made. The permanent magnet 13 is rotatable at a position adjacent to the inner peripheral surface of the coil portion 6. The back yoke 12 has a length in the axial direction exceeding the outer rotor body 11 and the permanent magnet 13. The end surfaces on the base end side of the outer rotor main body 11 and the back yoke 12 share one plane. On the other hand, the end surfaces of the permanent magnet 13 and the back yoke 12 on the front end side are substantially aligned.

  The support shaft 8 is made of metal such as iron, and includes a large-diameter bearing portion 8a that rotatably supports the inner rotor 15, and a pair of end portions 8b and 8c extending from both ends of the bearing portion 8a. The pair of end portions 8b and 8c have a smaller diameter than the bearing portion 8a. Of the pair of end portions 8 b and 8 c, the first end portion 8 b on the base end side is press-fitted into the support hole 2 a of the base housing portion 2. By this crimp fitting, a state in which the end surface on the base end side of the bearing portion 8a is in close contact with the end surface of the base housing portion 2 is obtained. On the other hand, after the inner rotor 15 is mounted on the bearing portion 8a, the side plate 9 is press-fitted to the second end portion 8c on the distal end side. By this crimp fitting, a state in which the end surface on the front end side of the bearing portion 8a is in close contact with the end surface of the side plate 9 is obtained. As a result of these crimp fittings, the base casing portion 2, the support shaft 8, and the side plate 9 are connected to each other so as not to rotate relative to each other.

  The pair of end portions 8b and 8c of the support shaft 8 have a common shaft core with the shaft core X of the electric pump, but the large-diameter bearing portion 8a of the support shaft 8 has a shaft core Y eccentric to the side from the shaft core X. Is provided. Further, trochoidal teeth that engage with each other are formed on the inner peripheral surface of the outer rotor body 11 and the outer peripheral surface of the inner rotor 15, but the outer teeth formed on the outer periphery of the inner rotor 15 The number of teeth is one less than the inner teeth formed around the circumference. A large number of pump spaces S are intermittently formed between the inner periphery of the outer rotor body 11 and the outer periphery of the inner rotor 15.

  When the magnetic field is rotated around the axis X in the direction of the arrow A in the annular coil portion 6, the outer rotor portion 10 is also driven to rotate in the A direction on the basis of the attraction / repulsion action with the permanent magnet 13. The inner rotor 15 is also rotationally driven in the A direction based on the engagement of the teeth. Since the rotation shaft core (Y) of the inner rotor 15 is eccentric from the shaft core X, each pump space S formed between the outer rotor body 11 and the inner rotor 15 by the rotational drive of the rotors 11 and 15 gradually. Move in direction A. Since the pump space S gradually decreases in volume while moving from the vicinity of the suction space 18 toward the vicinity of the discharge space 19, fluid is sucked into the pump space S from the suction port 18a, and the discharge port 19a is discharged from the pump space S. It is discharged through.

Near the outermost periphery of the side plate 9 attached to the second end portion of the support shaft portion 7, a first guided portion that is opposedly guided by the outer rotor portion 10 is provided. As shown in FIG. 2, the first guided portion includes a guided end surface 9 a that is guided by the end surface on the distal end side of the outer rotor main body 11.
On the other hand, the boss portion 3 of the base housing portion 2 is provided with a guide portion that guides the outer rotor portion 10 in a facing manner. As shown in FIG. 2, the guide portion includes an opposing end surface 3 a that guides the end surfaces on the base end side of the outer rotor body 11 and the back yoke 12 along the axis X, and an outer peripheral surface on the base end side of the back yoke 12. And an annular guide inner peripheral surface 3b for opposingly guiding from the outside in the radial direction. The permanent magnet 13 is configured not to come into contact with the base casing 2 and the annular casing 4. A return hole 9H formed so as to penetrate part of the side plate 9 so as to communicate with the suction space 18 restricts an increase in the internal pressure of the motor chamber M formed between the wall member 4a of the housing 1 and the side plate 9. To play a role.

  The second end portion 8 c of the support shaft 8 is fixed to the side plate 9, and the distal end side end surface of the outer rotor portion 10 is opposedly guided by the guided end surface 9 a on the proximal end side of the side plate 9, and the proximal end side of the outer rotor portion 10 Are opposed to each other by the opposed end surface 3 a of the base casing 2. Therefore, although the support shaft 8 is supported in a cantilever manner by the housing 1 substantially only by the first end portion 8b, the deflection of the outer rotor portion 10 with respect to the shaft core X is sufficiently suppressed.

  In the electric pump according to the present invention, as described above, since the support shaft 8 has a substantially cantilever structure, the inner surface of the annular casing portion 4 constituting the housing 1 is provided with the support shaft 8. It has an extremely simple structure that does not include a configuration for supporting the fitting. Therefore, the oil leaked from the pump space S to the motor chamber M between the wall member 4a of the housing 1 and the side plate 9 through a minute gap between the outer rotor portion 10 and the side plate 9 is relatively free. It can flow in the motor chamber M and return to the pump space S from the return hole 9H. From such a free flow of oil in the motor chamber M, a secondary effect of cooling the control board 20 is obtained.

[Another embodiment]
<1> As in the electric pump 60 shown in FIG. 5, the base casing portion 2 of the housing 1 may be provided with an opposing outer peripheral surface for opposingly guiding a part of the inner peripheral surface of the outer rotor portion 10. In the second embodiment, as shown in FIG. 6, the back yoke 12 includes a protruding portion 12 a that protrudes more proximally than the outer rotor main body 11 and the permanent magnet 13. The inner peripheral surface of the protruding portion 12 a of the back yoke 12 is rotatably supported by the outer peripheral portion of the auxiliary boss portion 3 s formed on the boss portion 3 of the base housing portion 2.

<2> In the electric pump 70 shown in FIG. 7, the base casing portion 2 of the housing 1 is opposed to the inner peripheral surface facing the outer peripheral portion of the outer rotor portion 10 or the inner portion of the outer rotor portion 10. There is no opposing outer peripheral surface that guides the peripheral surface. In the third embodiment, as shown in FIG. 8, the end surfaces on the base end side of the outer rotor main body 11 and the back yoke 12 share one plane, and these end surfaces support the base casing portion 2. It is only rotationally supported by the opposed end surface 3a formed on the boss 3t. The front end side end surface of the outer rotor main body 11 is rotatably supported by the guided end surface 9 a of the side plate 9, and the inner peripheral surface of the back yoke 12 is rotatably supported by the guide outer peripheral surface 9 b of the side plate 9.

<3> The support shaft portion 7 may be a member in which the support shaft and the flange-shaped side plate are integrally formed based on one-time injection molding of molten metal or the like.

Longitudinal sectional view of an electric pump according to the present invention The longitudinal cross-sectional view which expanded the principal part of the electric pump of FIG. Broken front view along III-III in FIG. 1 is an exploded perspective view of the electric pump of FIG. The longitudinal cross-sectional view of the electric pump by 2nd Embodiment of this invention The longitudinal cross-sectional view which expanded the principal part of the electric pump of FIG. The longitudinal cross-sectional view of the electric pump by 3rd Embodiment of this invention The longitudinal cross-sectional view which expanded the principal part of the electric pump of FIG.

DESCRIPTION OF SYMBOLS 1 Housing 2 Base housing | casing part 3 Boss part 3a Opposite end surface 3b Guide inner peripheral surface 3s Auxiliary boss part 3t Auxiliary boss part 4 Annular housing part 5 Cover housing part 6 Coil part 7 Support shaft part 8 Support shaft 8a Bearing part 9 Side plate (side plate part)
9a Guided end face 9H Return hole 10 Outer rotor portion 11 Outer rotor main body 12 Back yoke 12a Protruding portion 13 Permanent magnet 15 Inner rotor 18 Suction space 18a Suction port 19 Suction space 19a Suction port 50 Electric pump M Motor chamber S Pump space

Claims (4)

A housing that houses an annular coil portion;
An outer rotor portion that is driven to rotate based on the magnetic field of the coil portion inside the housing;
An inner rotor that is rotatably supported by a support shaft portion that is eccentric with respect to the outer rotor portion and has an outer peripheral surface that engages with an inner peripheral surface of the outer rotor portion;
Inhale / discharge fluid based on the displacement of the space formed between the outer rotor portion and the inner rotor due to the rotational drive of the outer rotor portion,
The support shaft portion includes a first end supported by the housing;
The outer rotor portion includes a pair of end surfaces that are opposed and guided so as to be sandwiched from the axial direction by the housing and the second end of the support shaft portion ,
A flange-shaped side plate portion provided at the second end of the support shaft portion and having an end surface facing the end surface of the outer rotor portion in the axial direction;
An electric pump having a hole penetratingly formed in the side plate portion and communicating with a space formed between the housing and the side plate portion and a space formed between the outer rotor portion and the inner rotor . 2. The electric pump according to claim 1 , wherein the housing is provided with an opposing inner peripheral surface that opposes and guides a part of the outer peripheral surface of the outer rotor portion in a radial direction. 2. The electric pump according to claim 1 , wherein the housing is provided with an opposing outer peripheral surface that opposes and guides a part of the inner peripheral surface of the outer rotor portion in a radial direction. The housing includes a base housing portion that supports the first end portion of the support shaft portion, and an annular housing portion that is attached to the base housing portion so as to accommodate the coil portion, and the outer rotor. The electric pump according to any one of claims 1 to 3 , wherein the one end surface of the part is opposedly guided in an axial direction by an end surface formed in the base housing part.

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