JP2018096269A - Electric pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To sufficiently secure accuracy for the mating surface on both side surfaces of a pump chamber and sealability, to suppress secondary failure, such as partial wear of a slide portion or increase of frictional resistance, as well as deterioration of pump efficiency.SOLUTION: In an electric pump, a pump part 8 is arranged on an inner peripheral side of a rotor 7 of an electric motor 5. The electric pump includes: a housing 2 comprising a housing body 3 and a cover 4; a stator 6 having a plurality of coils 15; the rotor 7 comprising an inside outer rotor 16 and an outside rotor body 17; side plates 11, 12 on both sides of the rotor 7; an inner rotor 9; and a plurality of connection plates 10 interposed between the outer rotor 16 and the inner rotor 9. One side plate 12 out of the pair of side plates 11, 12 is pushed against the rotor 7 by a compression coil spring 28.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a so-called motor-integrated and positive displacement electric pump in which an electric motor and a pump unit are integrated.

  For example, Patent Documents 1 to 3 propose a motor-integrated electric pump that is used as, for example, an automobile engine or a transmission oil pump, in which a pump portion is disposed on the inner peripheral side of the rotor of the electric motor. ing.

  In the motor-integrated electric pumps disclosed in these Patent Documents 1 to 3, the rotor of the electric motor also serves as the outer rotor of the positive displacement pump unit, and a predetermined gap is provided on the inner peripheral side of the outer rotor. Both are common in that the inner rotor, which is also a pump element, is arranged eccentrically. The outer rotor and the inner rotor form a trochoid type or other type of pump part, and the inner rotor rotates following the rotation of the outer rotor. It has come to be demonstrated.

JP 2011-7843 A JP 2012-67735 A JP 2012-41867 A

  However, in these motor-integrated electric pumps, as described in Patent Documents 1 and 3, a pump chamber is provided due to the structural speciality in which the pump portion is disposed on the inner peripheral side of the rotor of the electric motor. The housing member that restricts both sides of the bolt must be bolted at a position that is greatly separated from the center of the pump portion in the radial direction. Therefore, unless the housing member has a large thickness and high rigidity, it is difficult to accurately bring the housing member, the outer rotor, and the inner rotor into close contact with each other with the bolt fastening force. There is a concern about the deterioration and the sealing performance. As a result, the pump efficiency is reduced due to liquid leakage and the like, and the sliding part is unevenly worn, and the frictional resistance is likely to increase, and there is still room for improvement as a motor-integrated electric pump.

  The present invention has been made paying attention to such a problem, and ensures sufficient alignment accuracy and sealing performance on both sides of the pump chamber to reduce pump efficiency as well as uneven wear and friction of sliding parts. The present invention provides a motor-integrated electric pump capable of suppressing secondary problems such as an increase in resistance.

  The present invention is an electric pump in which a pump unit that is rotationally driven by an electric motor is disposed on an inner peripheral side of a rotor that forms an electric motor together with a stator, the housing having a sealed structure, and the housing A stator housed in the stator and having a plurality of coils in the circumferential direction; a rotor disposed on the inner circumferential side of the stator and serving as an outer rotor of the pump unit; and disposed on both sides of the rotor. A pair of side plates and an eccentric arrangement on the inner peripheral side of the rotor form a pump chamber of the pump unit together with the rotor and the pair of side plates, and rotate as the rotor rotates. And an inner rotor. In addition, at least one of the pair of side plates is pressed against the rotor by an elastic member.

  In this case, with respect to the rotor, in order to achieve both the function required for the electric motor and the function required for the pump unit, the rotor includes the pump chamber of the pump unit together with the pair of side plates and the inner rotor. The outer rotor is formed, and the rotor main body provided with a permanent magnet fitted to the outer peripheral side of the outer rotor and corresponding to the coil on the stator side. desirable.

  The pump unit may be a trochoidal type or other type of pump unit as long as it is structurally established. Here, the pump unit includes, for example, the outer rotor, a pair of side plates, and an inner rotor. In addition, one end is swingably supported by the outer rotor, and the other end is slidably fitted to the inner rotor, and the pump chamber space between the outer rotor and the inner rotor is separated into a plurality of regions. A structure having a plate member is assumed.

  As a more specific structure of the housing, the housing is formed of a housing body and a cover member that are divided into two in the axial direction of the rotor, and the outer rotor, the inner rotor, and a pair of sides on both sides thereof. It is desirable that the plate is pressed and held by the housing body and the cover member in order to improve the adhesion between the members.

  Further, when attention is paid to the rotational performance of the rotor, the outer rotor has a rim portion having a length longer than that of the rotor body at the peripheral portion thereof, and inner peripheral ends of both ends in the length direction of the rim portion. It is desirable that bearings are interposed between the surface and the housing main body or the cover member, respectively, and the rotor formed by the outer rotor and the rotor main body is rotatably supported by the bearings. .

  Therefore, in the present invention, at least one side plate of the pair of side plates is pressed against the rotor by the elastic force of the elastic member, thereby having an inner rotor on the inner peripheral side and also serving as the outer rotor of the pump unit. The rotor is sandwiched between the side plates by elastic force. For this reason, the rotor and inner rotor that also serve as the outer rotor of the pump unit and both side plates come into close contact with each other reliably, and the contact state can be stably maintained.

  According to the present invention, at least one of the pair of side plates forming the pump chamber is pressed against the rotor by the elastic member and has a so-called floating structure. The rotor and inner rotor, which also serve as the outer rotor of the pump section, can be brought into close contact with each other, ensuring sufficient surface alignment accuracy and sealability on both sides of the pump chamber, reducing pump efficiency and reducing sliding parts. Uneven wear and further increase in frictional resistance can be suppressed.

The figure which shows the more concrete 1st form for implementing the electric pump which concerns on this invention, and sectional drawing along the BB line of FIG. Sectional drawing along the AA line of FIG. The exploded perspective view when the cover of the electric pump shown in FIGS.

  1 to 3 show a more specific first embodiment for carrying out the electric pump according to the present invention. In particular, FIG. 1 is a cross-sectional view taken along the line BB of FIG. FIG. 2 is a sectional view taken along line AA of FIG. Further, FIG. 3 shows an exploded perspective view when the cover 4 of the electric pump 1 shown in FIGS.

  The electric pump 1 shown in FIGS. 1 to 3 includes a circular housing 2 sealed by a housing body 3 and a cover 4, and an electric motor 5 and a pump unit 8, which will be described later, are concentrically positioned in the axial direction. Are accommodated and arranged so as to coincide with each other, and the entire shape including the housing 2 is substantially flat.

  As shown in FIGS. 1 and 2, the electric motor 5 includes an annular stator (stator) 6 that occupies the outer peripheral portion of the circular internal space of the housing 2, and a cylindrical shape that occupies the internal space inside the stator 6. And a rotor (rotor) 7. On the other hand, the rotor 7 also serves as an outer rotor of the pump unit 8 to be described later. The pump unit 8 is arranged on the rotor 7 and an inner rotor 9 that is eccentrically arranged with a predetermined gap on the inner peripheral side of the rotor 7. And a plurality of connecting plates 10 that are radially interposed between the rotor 7 and the inner rotor 9, and a pair of side plates 11, 12 described later disposed on both sides of the inner rotor 9.

  As shown in FIGS. 1 and 3, the housing 2 housing the electric motor 5 and the pump unit 8 includes a housing body 3 and a cover 4 as a cover member in the axial direction of the stator 6 or the rotor 7. It is formed as a so-called halved structure divided into two. The housing body 3 and the cover 4 are brought into contact with each other and then fastened and fixed by the two bolts 13.

  The stator 6 of the electric motor 5 has a plurality of teeth portions 14a protruding at an equal pitch on the inner peripheral side of an annular metal stator core 14, and a coil 15 is wound around each of the teeth portions 14a. The coil 15 has a known structure, and each coil 15 including the tooth portion 14a forms a magnetic pole. On the other hand, as described above, the rotor 7 of the electric motor 5 also serves as the outer rotor of the pump unit 8. In the present embodiment, the inner peripheral side and the outer peripheral side of the rotor 7 are sufficient to satisfy the function required as the rotor of the electric motor 5 and the function required as the outer rotor of the pump unit 8. The rotor 7 has a hollow cylindrical outer rotor 16 on the inner peripheral side, and a hollow cylindrical rotor fitted to the outer peripheral side of the outer rotor 16. And a main body 17.

  The outer rotor 16 on the inner peripheral side is made of a single metal material, whereas the rotor body 17 on the outer peripheral side is formed of a steel sheet laminate such as electromagnetic steel sheets. Further, the rotor body 17 is formed with a plurality of slot portions 18 (the same number as the coils 15 on the stator 6 side) penetrating in the axial direction at equal pitch positions in the circumferential direction. The permanent magnet 19 is inserted into the base plate and fixed with an adhesive. As shown in FIGS. 1 and 2, a minute gap corresponding to a so-called air gap is secured between each tooth portion 14 a on the stator 6 side and the outer peripheral surface of the rotor body 17.

  Further, as shown in FIG. 1, the outer rotor 16 forming the rotor 7 together with the rotor body 17 described above is longer in the outer peripheral edge than the rotor body 17 (length in the axial direction). A rim portion 20 having a large height and a step is formed, and the rim portion 20 projects from both ends of the rotor body 17. After the end plate 21 made of a nonmagnetic material such as an aluminum plate is overlapped on both end faces of the rotor body 17 to cover the permanent magnet 19, the rotor body 17 is attached to the small diameter portion of the rim portion 20 of the outer rotor 16. The rotor main body 17 is integrally fixed to the outer periphery of the outer rotor 16 by press-fitting into the stopper ring 22. Thus, at least the rotor body 17 forms the permanent magnet embedded type electric motor 5 together with the stator 6.

  Note that the end plate 21 made of a non-magnetic material is provided to suppress a decrease in output due to magnetic flux leakage of the permanent magnet 19 embedded in the rotor body 17. When the entire rotor 7 composed of the outer rotor 16 and the rotor body 17 is integrally formed of a steel plate laminate or other metal material, the rotor 7 is connected to the rotor 7 of the electric motor 5. As described above, it also serves as the outer rotor 16 of the pump unit 8.

  As shown in FIGS. 1 and 2, a cylindrical inner rotor 9 having a diameter smaller than the inner diameter of the outer rotor 16 is formed on the inner peripheral surface of the outer rotor 16 at a position eccentric from the axial center position of the outer rotor 16. It is arranged so as to be inscribed, and a space between the two serves as a pump chamber P of the positive displacement pump unit 8. The inner rotor 9 is formed with a plurality of square groove-like slot portions 23 that are radially open at an outer peripheral surface and extend in the radial direction. In each slot portion 23, a connecting plate 10 having a deformed vane shape as a plate member is slidably inserted, and supported so as to be able to protrude and retract from each slot portion 23. Each connecting plate 10 has a substantially keyhole shape in cross-section, and is formed as a cylindrical rocking shaft portion 10a having a thick base portion on the inner rotor 9 side and a tip portion on the opposite outer rotor side being thinner than the base portion. .

  On the other hand, a plurality of cylindrical slot-shaped support holes 24 extending in the axial direction are formed at an equal pitch on the inner peripheral surface of the outer rotor 16, and the swinging shaft portions 10 a of the connection plates 10 are formed in these support holes 24. It is fitted and supported so that it can rotate. As a result, each connecting plate 10 can swing about the swinging shaft portion 10a and is prevented from being detached from the outer rotor 16, and the base portion does not come out from the slot portion 23 of the inner rotor 9. It can appear and disappear from the slot portion 23. As described above, the plurality of coupling plates 10 are disposed in a bridging manner between the outer rotor 16 and the inner rotor 9, so that the pump chamber P formed between the outer rotor 16 and the inner rotor 9 is separated into a plurality of regions. It has come to be.

  As shown in FIG. 1, a relatively large-diameter support convex portion 3 a is formed in the central portion of the inner bottom surface of the housing body 3, leaving a space R <b> 1 facing the stator 6. Similarly, an annular support convex portion 4 a is formed at the center of the inner bottom surface of the cover 4, leaving a space R <b> 2 facing the stator 6. Ball bearings 25 and 26 are respectively provided as bearings between the support convex portion 3a on the housing body 3 side and the support convex portion 4a on the cover 4 side, and both ends in the length direction of the rim portion 20 of the outer rotor 16. It is intervened. As a result, the outer rotor 16 and thus the rotor 7 are rotatably supported by bearings in such a manner that they are supported by the support protrusions 3a and 4a on the housing body 3 and the cover 4 side.

  A side plate 11 on the housing body 3 side and a side plate 12 on the cover 4 side are arranged on both side surfaces of the inner rotor 9 so as to extend over a part of the outer rotor 16. Since both of these side plates 11 and 12 are present, the pump chamber P formed between the outer rotor 16 and the inner rotor 9 is isolated in the axial direction as shown in FIG. Thus, the positive displacement pump section 8 is formed by the outer rotor 16, the inner rotor 9, the connecting plate 10, and both side plates 11 and 12.

  Further, as shown in FIG. 1, a stepped shaft is formed in such a manner as to penetrate the inner rotor 9 and the side plate 11 on the housing body 3 side and extend over the support convex portion 3a on the housing body 3 side and the side plate 12 on the cover 4 side. The shaft member 27 is arranged. The shaft member 27 rotatably supports the inner rotor 9 at the center in the longitudinal direction, while both ends in the longitudinal direction are fitted and supported by the support protrusion 3a on the housing body 3 side and the side plate 12 on the cover 4 side. Has been. As described above, the side plate 11 on the housing body 3 side, the inner rotor 9, and the side plate 12 on the cover 4 side are respectively assembled with the shaft member 27 fitted and supported by the support convex portion 3 a on the housing body 3 side. Therefore, relative positioning between the members is performed.

  A stepped boss portion 12a is formed on the back side of the side plate 12 on the cover 4 side shown in FIG. 1, and this boss portion 12a is pivoted on the inner periphery of the annular support convex portion 4a on the cover 4 side. It is fitted and supported so as to be slidable in the center direction. A compression coil spring 28 is disposed as an elastic member on the outer periphery of the small diameter portion of the boss portion 12a. The compression coil spring 28 is disposed between the boss portion 12a and the inner bottom surface of the support convex portion 4a on the cover 4 side. It is inserted in a compressed state. Thereby, the side plate 12 on the cover 4 side has a so-called floating structure, and the side plate 12 is pressed against the inner rotor 9 and the outer rotor 16 by the elastic force of the compression coil spring 28. This is nothing but the inner rotor 9 and the outer rotor 16 and both side plates 11 and 12 disposed on both sides of the inner rotor 9 and the outer rotor 16 are pressed so as to be in close contact with each other. As a result, the adhesion between the inner rotor 9 and the outer rotor 16 and the side plates 11 and 12 and the sealing performance are ensured.

  As shown in FIGS. 1 and 2, a suction port 29 and a discharge port 30 communicating with the pump chamber P are formed in the side plate 11 on the housing body 3 side. On the other hand, the side plates 12 on the cover 4 side are also formed with recesses 31 and 32 respectively communicating with the suction port 29 and the discharge port 30 through the slot portion 23 on the inner rotor 9 side where the coupling plate 10 is inserted. The suction port 29 and the discharge port 30 are respectively connected to a suction port and a discharge port (not shown) formed in the housing body 3. In addition, annular grooves 33 and 34 are respectively formed on the inner side surfaces of the side plates 11 and 12 facing the inner rotor 9 so as to surround the shaft member 27. In the portion corresponding to the suction port 29 and the discharge port 30 and the annular groove 33 formed in one side plate 11 and in the portion corresponding to the concave portions 31 and 32 and the annular groove 34 formed in the other side plate 12. Side clearances are respectively set as minute gaps between the side surfaces of the inner rotor 9.

  Here, in the present embodiment, it is assumed that the electric pump 1 is an oil pump, and the annular grooves 33 and 34 formed in both the side plates 11 and 12 are respectively connected to the side plates 11 and 12 and the inner rotor. For oil lubrication at the sliding portion with respect to 9, a part of the oil to be pumped is held as lubricating oil.

  Further, the suction port 29 or the discharge port 30 formed in the side plate 11 on the housing body 3 side faces, for example, the ball bearing 25 shown in FIG. 1, and part of the oil to be pumped is both ball bearings. The spaces R1 and R2 on the housing main body 3 side and the cover 4 side including 25 and 26 and the stator 6 are also filled. As a result, in addition to the ball bearings 25 and 26, the stator 6 and the rotor 7 including the coils 15 are immersed in the oil to be pumped. Along with lubrication, the stator 6 and the rotor 7 are cooled by oil.

  Therefore, in the electric pump 1 configured as described above, each coil 15 is energized by energizing each coil 15 of the stator 6 forming the electric motor 1 together with the rotor 7 as shown in FIGS. The rotor 7 in which the permanent magnet 19 corresponding to the rotor 7 is embedded, that is, the rotor 7 in which the rotor main body 17 in which the permanent magnet 19 is embedded and the outer rotor 16 are integrated is included in both ball bearings 25, 26. For example, it rotates in the direction of arrow M, which is the clockwise direction in FIG.

  In FIG. 1, the shaft member 27 and the side plates 11 and 12 are drawn concentrically. However, as is apparent from FIG. Since the axis of the shaft member 27 is eccentric with respect to the axis of the side plates 11 and 12, the side plates 11 and 12 do not rotate with the rotation of the rotor 7.

  The rotation of the rotor 7 described above is transmitted to the inner rotor 9 through a plurality of connecting plates 10 interposed between the outer rotor 16 and the inner rotor 9. As shown in FIG. 2, the inner rotor 9 is eccentric with respect to the axial center of the rotor 7, so that the inner rotor 9 rotates integrally with the outer rotor 16, and at the same time, the inner rotor with the shaft member 27 as the center of rotation. 9 itself also rotates while inscribed in the inner peripheral surface of the outer rotor 16 and continuously changing the inscribed position.

  As the inner rotor 9 rotates about the shaft member 27 while being inscribed in the inner peripheral surface of the outer rotor 16, the connecting plates 10 inserted into the slot portions 23 of the inner rotor 9 are shaken. Since the protrusions and recesses from the respective slot portions 23 are repeated while swinging around the moving shaft portion 10a, the function as a so-called positive displacement pump is exhibited by the protrusions and recesses of the respective connecting plates 10 in the pump chamber P. It becomes.

  More specifically, since the plurality of connecting plates 10 arranged between the outer rotor 16 and the inner rotor 9 isolate the pump chamber P into a plurality of regions, they are sandwiched between two adjacent connecting plates 10. 2 is a suction (intake) process, and the region sandwiched between two adjacent connecting plates 10 is a substantially crescent shaped discharge port in FIG. The process of passing 30 is the discharge stroke. And by repeating such a behavior continuously, the function as a positive displacement pump by the pump part 8 is exhibited as described above.

  In the process where the pump unit 8 functions as a positive displacement pump, the side plate 12 on the cover 4 side is pressed against the side surfaces of the outer rotor 16 and the inner rotor 9 by the compression coil spring 28 as shown in FIG. The outer rotor 16 and the inner rotor 9 that have received the pressing force of the side plate 12 are pressed against the side plate 11 on the housing body 3 side. This means that the side plates 11 and 12 arranged on both sides of the outer rotor 16 and the inner rotor 9 sandwich the outer rotor 16 and the inner rotor 9 between them due to the elastic force of the compression coil spring 28. Yes. Therefore, as shown in FIG. 1, even if the fastening fixing position between the housing body 3 and the cover 4 by the bolt 13 is relatively far from the pump portion 8, the outer rotor 16 and the inner rotor that are the main elements of the pump portion 8. Both side plates 11 and 12 are always in close contact with the side surface 9, so that the accuracy of the mating surfaces of the two is improved and the sealing performance is improved. Accordingly, the outer rotor 16 and the inner rotor 9 are stably rotated, and oil leakage from the pump chamber P is suppressed, and the pump efficiency is improved.

  In addition, as described above, a side clearance is set in a part of the contact surface of both the side plates 11 and 12 with respect to the outer rotor 16 and the inner rotor 9, and oil is interposed in the part to perform oil lubrication. It has come to be. Therefore, uneven wear at the portion can be suppressed, and frictional resistance can be reduced. This also allows the outer rotor 16 and the inner rotor 9 to rotate more stably.

  In addition, since the rotor 7 is supported by the ball bearings 25 and 26 in a doubly supported manner at the radially outer portion, not at the portion near the rotation center position, the rotation of the rotor 7 is also stabilized. Therefore, the durability of the electric pump 1 including the ball bearings 25 and 26 is also improved.

  Furthermore, there is no need to make the entire housing 2 formed of the housing body 3 and the cover 4 thick or highly rigid, and the electric pump 1 in which the electric motor 5 and the pump unit 8 are integrated is as follows. As shown in FIG. 1, a flat and compact structure can be obtained.

  Here, in the present embodiment, as illustrated in FIG. 2, the pump unit 8 of a type in which a plurality of connection plates 10 are interposed between the outer rotor 16 and the inner rotor 9 in a bridging manner is described as an example. However, the type of the pump unit 8 is not limited to this, and may be another type of pump unit such as a trochoid type.

  In the present embodiment, as shown in FIG. 2, with respect to the rotor 7, in order to sufficiently satisfy both the function required for the electric motor 5 and the function required for the pump unit 8. 7 is formed by the outer rotor 16 and the rotor body 17, but may be formed as a structure in which both are completely integrated with the same material as required.

DESCRIPTION OF SYMBOLS 1 ... Electric pump 2 ... Housing 3 ... Housing main body 4 ... Cover (cover member)
DESCRIPTION OF SYMBOLS 5 ... Electric motor 6 ... Stator 7 ... Rotor 8 ... Pump part 9 ... Inner rotor 10 ... Connection plate (plate member)
DESCRIPTION OF SYMBOLS 11 ... Side plate 12 ... Side plate 15 ... Coil 16 ... Outer rotor 17 ... Rotor main body 19 ... Permanent magnet 20 ... Rim part 25 ... Ball bearing (bearing)
26 ... Ball bearing
28: Compression coil spring (elastic member)
P ... Pump room

Claims (5)

An electric pump in which a pump unit that is rotationally driven by the electric motor is disposed on the inner peripheral side of the rotor that forms the electric motor together with the stator,
A sealed housing;
A stator housed in the housing and having a plurality of coils in the circumferential direction;
A rotor disposed on the inner peripheral side of the stator and serving also as an outer rotor of the pump unit;
A pair of side plates disposed on both sides of the rotor;
An inner rotor that is eccentrically arranged on the inner peripheral side of the rotor and forms a pump chamber of the pump unit together with the rotor and the pair of side plates, and rotates with the rotation of the rotor;
With
An electric pump, wherein at least one of the pair of side plates is pressed against a rotor by an elastic member. The rotor is
An outer rotor that forms a pump chamber of the pump unit together with the pair of side plates and the inner rotor;
A rotor body provided with a permanent magnet fitted to the outer peripheral side of the outer rotor and corresponding to a coil on the stator side;
The electric pump according to claim 1, wherein the electric pump is formed from the following. The pump part is
In addition to the outer rotor and the pair of side plates and the inner rotor,
A plate member whose one end is swingably supported by the outer rotor and the other end is slidably fitted to the inner rotor and separates the pump chamber space between the outer rotor and the inner rotor into a plurality of regions. The electric pump according to claim 2, wherein the electric pump is provided. The housing is
It is formed of a housing body and a cover member that are divided in the axial direction of the rotor,
4. The electric pump according to claim 3, wherein the outer rotor, the inner rotor, and a pair of side plates on both sides thereof are pressed and held by a housing body and a cover member. The outer rotor has a rim portion having a length longer than that of the rotor body at the peripheral portion thereof, and
A bearing is interposed between the inner peripheral surface of both end portions in the length direction of the rim portion and the housing body or the cover member,
5. The electric pump according to claim 4, wherein a rotor formed by the outer rotor and the rotor main body is rotatably supported by the bearings. 6.

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