JP2012167621A - Electric oil pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric oil pump having a simple constitution which can improve the efficiency of the magnetic force, and reduce the number of components, and miniaturized.SOLUTION: A stator A includes a lower stator core 1 consisting of a stator pole 12 which is formed of an insulating sintered body, and projected toward the center from the inner peripheral side of a cylindrical core body 11, and a lower tooth piece 13 formed on an inner end of the stator pole 12, a coil 14 wound around the stator pole 12, and an upper stator core 2 formed on an upper end of the lower tooth piece 13 and having an upper tooth piece 22. An inner rotor 4 and a rotor magnet 3 are integrated with each other using a resin. A magnetic pole to be attracted to and repelled by a magnetic pole of the stator A is provided in an inner rotor 4 and a rotor magnet 3 in the form of a plastic magnet or a built-in magnet.

Description

  The present invention relates to an electric oil pump having a simple configuration that can improve the efficiency of magnetic force and can be reduced in size by reducing the number of components.

  Conventionally used electric oil pumps are a combination of a motor having a drive shaft and an oil pump having a rotating shaft. In such an electric oil pump in which a motor and an oil pump are combined, a space for a connecting portion between the motor drive shaft and the oil pump rotation shaft is required, which is an obstacle to miniaturization of the entire apparatus.

  Therefore, a configuration in which the motor drive shaft and the oil pump rotation shaft are shared and a coupling portion is not required and the size can be reduced can be considered. In this specification, an electric oil pump having such a configuration is referred to as an integrated electric oil pump. Called a pump. Patent Document 1 discloses such an integrated electric oil pump.

  The electric internal gear pump disclosed in Patent Document 1 is configured as a trochoid pump which is a kind of internal gear pump. The pump 1 houses a motor unit 3 and a rotor unit 4 inside a housing 2, and is a drive shaft that is rotationally driven by the motor unit 3 and a main shaft 5 that also serves as a rotation axis of the rotor unit 4. Is rotatably provided. One end of the main shaft 5 in the axial direction is rotatably supported by the first rolling bearing 6, and the other end of the main shaft 5 in the axial direction is rotatably supported by the second rolling bearing 7. Yes.

  The housing 2 is configured by connecting a housing body 21 and a lid body 22 which are divided into two in the axial direction of the main shaft 5. The lid 22 is made of, for example, a steel plate and is formed in a disc shape so as to close the open side of the housing body 21, and a suction port (not shown) through which hydraulic oil is sucked and a discharge port through which hydraulic oil is discharged 8 and. The motor unit 3 includes a stator 31 provided inside the housing body 21 and a rotor 32 disposed inside the stator 31. The main shaft 5 serving as a drive shaft is combined with the rotor 32 so as to rotate integrally, and the main shaft 5 extends from the rotor 32 toward the rotor portion 4 in the axial direction.

  The main shaft 5 includes a hollow cylindrical shaft portion 51 and a rotor extension portion 52 formed at one end of the shaft portion 51 and extending radially outward. The inner rotor 42 of the rotor part 4 is combined with the outer peripheral surface 52a of the rotor extension part 52 of the main shaft 5 so as to be integrally rotatable. The rotor 32 and the inner rotor 42 rotate integrally through the main shaft 5. Therefore, when the rotor 32 is rotated by the action of the motor unit 3, the inner rotor 42 is also rotated, and the rotor unit 4 can exhibit a function as a pump.

JP 2004-278444 A

  Patent Document 1 has the following problems. First, since the rolling bearings 6 and 7 are used, the cost is higher than that of the sliding bearing. Further, since the rolling bearings 6 and 7 are used, the outer diameter of the electric internal gear pump as a whole is increased by the distance in the radial direction of the rolling bearings 6 and 7, and a large space is required for installation.

  In addition, since the rotor 32, the shaft portion 51, and the inner rotor 42 are separate members, the number of parts is large, and as a result, assembly work is added, which is also a factor of high cost. Further, in Patent Document 1, the motor unit 3 is composed of an in-oil motor that can operate even in hydraulic oil. However, if the entire region of the motor unit 3 including the coil and the like is not completely insulated, Since it is not established, the cost is high.

  In addition, since the material of the inner rotor 42 and the outer rotor 41 is not described, the material cannot be grasped, but if it is a generally widely used sintered metal, the magnetic force of the stator 31 and the rotor 32 escapes through the rotor. Therefore, the motor output cannot be increased so much. A problem (technical problem) to be solved by the present invention is to provide an integrated electric oil pump having a simple configuration capable of improving the efficiency of magnetic force and reducing the number of parts to reduce the size. It is in.

  In view of the above, the inventor has intensively and intensively studied to solve the above-mentioned problems. As a result, the rotor magnet below the inner rotor is disposed on the inner peripheral side of the stator mounted in the pump body. In the electric oil pump in which the rotor magnet is provided rotatably on a shaft mounted on the pump body, the stator is formed of an insulating sintered body and is centered from the inner peripheral side of the cylindrical core body. A lower stator core composed of a stator pole formed so as to protrude toward the inner side and a lower teeth piece formed at the inner end of the stator pole, a coil wound around the stator pole, and an upper end of the lower teeth piece And an upper stator core having an upper teeth piece, and the inner rotor and the rotor magnet are made of resin. Together are integrally formed by pole and suction and magnetic poles repel the stator has an electric oil pump which thus provided a plastic magnet or the embedded magnets on the inner rotor and the rotor magnet, the above-mentioned problems are eliminated.

  According to a second aspect of the invention, in the first aspect, the electric oil pump in which the other end of the shaft is fixed to a pump cover that covers the pump chamber of the pump body solves the above problem. According to a third aspect of the present invention, in the first or second aspect, the outer rotor corresponding to the inner rotor is an electric oil pump made of a nonmagnetic metal, thereby solving the above-mentioned problem.

  According to the first aspect of the present invention, the integrated rotor magnet and the inner rotor are rotatably mounted on the stator mounted in the pump body so as to be rotatable on the shaft fixed to the pump body. It is configured. A magnetic pole that attracts and repels the magnetic pole of the stator is provided on the rotor magnet and the inner rotor by a plastic magnet or an embedded magnet. As a result, the rotor magnet and inner rotor integrated with the stator are driven in two directions in the axial direction and the diametrical direction, so that the motor torque is improved, and the size, weight and efficiency can be improved.

  The hollow hole and center hole of the rotor magnet and inner rotor serve as bearing through holes, and the shaft mounted on the pump body passes through the rotor magnet and inner rotor so that expensive rolling bearings are used. It can be made unnecessary. Furthermore, since the rolling bearing is unnecessary, the outer diameter of the pump as a whole can be reduced by the distance in the radial direction of the rolling bearing.

  In the invention of claim 2, since the shaft end of the shaft is fixed not only to the pump body but also to the pump cover side, the shaft is firmly fixed, and the vibration during pump operation can be prevented, thereby improving durability. To do. In the third aspect of the invention, the outer rotor is made of resin or non-magnetic metal material, so that the magnetic force is difficult to escape through the outer rotor, magnetic loss of the inner rotor and stator can be prevented, and the motor torque can be further increased.

(A) is a longitudinal side view showing the configuration of the present invention, (B) is an enlarged view of part (A) of (A), and (C) is a cross-sectional view taken along arrow X1-X1 in (A). (A) is an X2-X2 arrow expanded sectional view of FIG. 1 (A), (B) is an X3-X3 arrow expanded sectional view of FIG. 1 (A). (A) is a perspective view of a stator, (B) is an exploded enlarged view of the (A) part of (A). (A) is a perspective view of the integrated rotor magnet and inner rotor, (B) is a bottom view of the integrated rotor magnet and inner rotor as seen from the rotor magnet side, and (C) is a magnetic pole embedded in the rotor magnet. It is a principal part expanded sectional view comprised with the magnet. It is a vertical side view of the state which decomposed | disassembled the main structural member of this invention. It is a principal part expanded sectional view which shows the effect | action of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present invention mainly includes a stator A, a rotor magnet 3, an inner rotor 4, an outer rotor 5, a pump body 6, a pump cover 7, and a shaft 8 as shown in FIGS. It consists of. As shown in FIGS. 1B and 3, the stator A is divided into two as a whole, and includes a lower stator core 1 and an upper stator core 2.

  The lower stator core 1 and the upper stator core 2 are made of a sintered material (sintered metal) and are configured as an insulating sintered body. The electric oil pump of the present invention has a vertical direction, and in a state where the rotor magnet 3 and the inner rotor 4 integrated with the pump body 6 are mounted, the inner rotor 4 side is the upper side, and the rotor magnet 3 side is the lower side. Become. When illustrated, the arrangement of FIG. 1A is the vertical direction in the present invention.

  The lower stator core 1 is formed at the inner end of the stator pole 12 and a plurality of stator poles 12 formed so as to protrude toward the center from the inner peripheral side of the cylindrical or annular core body 11. It consists of a lower tooth piece 13 (see FIG. 3A). The stator pole 12 is formed as an angular axis having a substantially square cross section, and the lower teeth piece 13 is formed as a plate piece having an arc shape in cross section.

  The stator poles 12 are formed on the core body 11 such that an even number of 4 or more are equally spaced. In the embodiment of the present invention, six stator poles 12 are formed in total (see FIG. 1C). The six stator poles 12 are arranged at an interval of 60 degrees with respect to the diameter center of the core body 11 and are configured to have six magnetic poles. Further, the number of the lower teeth 13 is naturally the same as the number of the stator poles 12, and is 6 in the embodiment of the present invention. The plurality of lower teeth pieces 13, 13,... Form a substantially circumferential wall surface body having gaps at equal intervals on the inner peripheral side of the core body 11. A coil 14 is wound around each stator pole 12.

  If the pump body 6 is made of an iron alloy or an aluminum alloy, the lower stator core 1 and the upper stator core 2 of the stator A are covered with an insulating resin insulator for insulation. That is, the stator A and the pump body 6 may be insulated from each other by some means.

  The upper stator core 2 is formed above the lower stator core 1 (see FIG. 3A). The upper stator core 2 includes an extended support piece 21 and an upper teeth piece 22, and the extended support piece 21 and the upper teeth piece 22 are formed in an L shape in cross section (see FIG. 3B). Specifically, an extension support piece 21 is formed from the upper end of each lower teeth piece 13 of the lower stator core 1, and an upper teeth piece 22 is formed at the upper end of the extension support piece 21.

  Therefore, in the upper stator core 2, the extension support pieces 21 and the upper teeth pieces 22 are the same as the number of the lower teeth pieces 13, and in the present invention, the number is the same as the number of the lower teeth pieces 13. The upper teeth piece 22 is formed outward from the upper end of the extended support piece 21 (in the same direction as the outer diameter direction of the core body 11). Further, the surface of the upper tooth piece 22 is configured to be perpendicular to the surface of the lower tooth piece 13 (see FIGS. 1A, 1B, and 6).

  The planar shape of the upper teeth piece 22 is formed in a substantially trapezoidal shape or a substantially fan shape that gradually becomes wider outward (see FIGS. 2A and 3). .. Are arranged so as to be radial with respect to the diameter center of the core body 11 (see FIG. 2A). The extended support piece 21 has substantially the same shape as the lower teeth piece 13 and is formed as an arc-shaped plate piece.

  The extension support piece 21 and the upper teeth piece 22 of the upper stator core 2 are integrally formed, but the upper stator core 2 and the lower stator core 1 are separate members (see FIG. 3B). Then, the extended support piece 21 of the upper stator core 2 is bonded and fixed to the lower teeth piece 13 of the lower stator core 1 with an adhesive or the like.

  If the lower stator core 1 and the upper stator core 2 are separate members and are fixed together with an adhesive, the coil 14 is wound around the stator pole 12 before the upper stator core 2 is bonded to the lower stator core 1. Work becomes extremely easy. Preferably, a concave portion where the upper teeth piece 22 is set is formed in the pump body 6, and the upper teeth piece 22 is inserted into the concave portion. Further, the lower teeth piece 13 is set so as to coincide with the extended support piece 21.

  Further, as a modification of the upper stator core 2, the upper support piece 21 is not provided, and only the upper teeth piece 22 is provided. In the lower stator core 1, the upper end of the lower teeth piece 13 is extended upward to form the lower teeth piece 13. It is also possible to form the upper stator core 2 by forming the upper teeth piece 22 directly on the upper end of the upper stator core 2. Further, the lower stator core 1 and the upper stator core 2 may be integrally formed. In this case, it is necessary to form the lower stator core 1 and the upper stator core 2 from a sintered material so that they can be integrally formed.

  When the coil 14 of the stator A is energized, the polarities of the magnetic poles by the lower teeth piece 13 and the upper teeth piece 22 are the same. And since it has a plurality of lower teeth pieces 13 and the same number of upper teeth pieces 22, a normal electromagnet could only generate magnetic flux in one direction, but the lower teeth pieces 13 and the upper teeth pieces. Thus, magnetic fluxes in two different directions (axial direction and diametrical direction) can be generated (see FIG. 6).

  At this time, each lower teeth piece 13 and the upper teeth piece 22 formed in a pair form magnetic poles having the same polarity when excited. That is, when an arbitrary set of stator poles 12 and lower teeth 13 are S poles, the upper teeth 22 of the upper stator core 2 formed on the lower teeth 13 are also magnetized and S poles. A set of a lower tooth piece 13 and an upper tooth piece 22 arranged in the circumferential direction of the core body 11 includes a control circuit so as to rotate in the arrangement of S, N, S, N,. Is done.

  Next, the rotor magnet 3 and the inner rotor 4 will be described. The rotor magnet 3 and the inner rotor 4 are made of synthetic resin. Specifically, a plastic magnet is used. Here, the plastic magnet is a resin containing a magnet, and is made by molding a powdered magnet together with the resin. However, normally, the ratio of magnet to resin is about 2: 1, and resin exists as a connection between powdered magnets.

  As shown in FIGS. 4A and 4B, the rotor magnet 3 is formed in a hollow cylindrical shape, and from the position of the diameter center of the inner rotor 4 to the diameter direction of the inner rotor 4. It is integrally formed so as to be a right angle. The outer diameter of the rotor magnet 3 is much smaller than the minimum outer diameter portion of the inner rotor 4 (that is, the diameter of the root circle) (see FIGS. 4A and 4B). Further, the outer peripheral side surface 31 of the rotor magnet 3 is accommodated on the inner peripheral side of a cylindrical inner peripheral wall formed by a plurality of lower teeth pieces 13, 13,... Of the stator A mounted on the pump body 6. Yes.

  A hollow hole 32 is formed in the rotor magnet 3 along the axial direction, and a shaft 8 to be described later is inserted (see FIGS. 1 and 2). The diameter of the hollow hole 32 is the same as the diameter of the center hole 42 of the inner rotor 4 and is formed so as not to cause a step. The rotor magnet 3 and the inner rotor 4 are rotatable by a shaft 8 described later. The rotor magnet 3 and the inner rotor 4 are both formed from the same material, and are most preferably formed integrally.

  The rotor magnet 3 and the inner rotor 4 may be formed separately, and the inner rotor 4 and the rotor magnet 3 may be fixed with an adhesive. Actually, since the inner rotor 4 and the rotor magnet 3 are integrally formed, the number of parts of the entire apparatus can be reduced, and the hollow hole 32 of the rotor magnet 3 and the center hole 42 of the inner rotor 4 are integrally formed. Therefore, it is possible to form an accurate shaft bearing hole with no step in the axial direction (see FIG. 5).

  Each of the inner rotor 4 and the rotor magnet 3 is divided into an even number in the circumferential direction by a plastic magnet or an embedded magnet m [see FIG. Is provided. Here, the case of using four magnetic poles will be described. Further, a portion indicating the magnetic pole of the rotor magnet 3 is denoted by reference numeral 3m, and a portion indicating the magnetic pole of the inner rotor 4 is denoted by 4m, which is indicated in the drawing.

  First, in the cylindrical rotor magnet 3, the magnetic poles are configured as permanent magnets so that they are divided into four equal parts at intervals of 90 degrees along the circumferential direction of the outer peripheral side surface 31, and alternate with S poles, N poles,. Has been. The inner rotor 4 is also configured as a permanent magnet that is divided into four equal parts at intervals of 90 degrees in the circumferential direction and alternates with S poles, N poles,.

  Here, the arrangement of the magnetic poles on the rotor magnet 3 side and the arrangement of the magnetic poles on the inner rotor 4 side are configured to have the same phase (see FIGS. 4A and 4B). In the 6-pole stator as in the present invention, the 4 poles are magnetized by energization of the coil 14, and the magnetic pole center of the stator A corresponding to the magnetic pole center of the rotor magnet 3 does not match. A force that changes the phase in the rotation direction is generated in the magnet 3, and the rotor magnet 3 rotates.

  The inner rotor 4 constitutes a trochoidal gear pump together with an outer rotor 5 to be described later (see FIG. 2B), and the inner rotor 4 has an outer tooth portion 41 formed on the outer periphery thereof. Specifically, the outer tooth portion 41 has a trochoidal tooth profile and meshes with an inner tooth portion 51 of the outer rotor 5 described later to constitute a trochoid pump. A center hole 42 through which the shaft 8 described later passes is formed at the center position of the diameter of the inner rotor 4 (see FIGS. 4A and 5).

  The outer rotor 5 is formed in an annular shape, and an inner tooth portion 51 that protrudes from the inner peripheral side toward the center side is formed [see FIG. 2 (B)]. Then, the inner rotor 4 is disposed on the inner peripheral side of the outer rotor 5, and the cell J that is an interdental space is formed by combining the outer tooth portion 41 of the inner rotor 4 and the inner tooth portion 51 of the outer rotor 5. Is formed. The outer rotor 5 is made of resin or a non-magnetic metal material, so that the magnetic force is difficult to escape through the outer rotor 5, the magnetic loss of the inner rotor 4 and the stator A can be prevented, and the motor torque can be further increased.

  The pump body 6 is made of a nonmagnetic metal such as a nonmagnetic iron alloy or nonferrous metal, an aluminum alloy, or a resin, and a motor chamber 61 and a pump chamber 62 are formed from the inner back side. Because of such a configuration, the pump body 6 is preferably a hollow cylinder. The pump chamber 62 is formed as a concave recess in which the outer rotor 5 is rotatably accommodated on the surface where the pump cover 7 described later is joined. The stator A is attached to the motor chamber 61.

  When the pump body 6 is made of synthetic resin, the stator A is attached to the motor chamber 61 by dividing the pump body 6 and assembling the stator A or by insert insertion by casting. When the pump body 6 is made of metal, the pump body 6 is composed of two members, and the pump body 6 is disassembled so that the stator A can be easily mounted. However, the mounting means for the stator A to the pump body 6 as described above is not limited, and any mounting means may be used.

  In the configuration in which the stator A is mounted in the motor chamber 61, the surface of the lower teeth piece 13 is exposed from the inner peripheral wall surface of the motor chamber 61 (see FIG. 1A, FIG. 5, and FIG. 6). A plurality of lower teeth pieces 13, 13,... Of the stator A mounted in the motor chamber 61 constitute a substantially cylindrical hole-shaped inner peripheral wall surface having gaps at equal intervals. Further, the plurality of upper teeth pieces 22, 22,... Of the stator A are arranged with their surfaces exposed from the bottom surface 62a of the pump chamber 62 (see FIGS. 2A and 6).

  Further, the shaft 8 is mounted from the motor chamber 61 of the pump body 6 toward the pump chamber 62 (see FIGS. 1A and 5). Specifically, the axial direction of the shaft 8 is such that the pump body 6 passes through the central position of the diameter of the cylindrical inner peripheral wall surface portion constituted by a plurality of lower teeth pieces 13, 13,. It is attached to the body 6. The shaft 8 is made of a hard and rust-resistant metal such as stainless steel, and is a solid (filled) cylindrical shaft. One end of the shaft 8 in the axial direction is the bottom of the motor chamber 61 of the pump body 6. Are fixed by fixing means such as embedding.

  The rotor magnet 3 with which the shaft 8 is integrated and the inner rotor 4 are inserted so as to penetrate the hollow hole 32 and the center hole 42. That is, the integrated inner rotor 4 and rotor magnet 3 are structured to rotate in the circumferential direction around the fixed shaft 8. Therefore, it is preferable that the center hole 42 of the inner rotor 4 and the hollow hole 32 of the rotor magnet 3 are subjected to surface finishing so that the shaft 8 can rotate smoothly without causing rattling.

  In the motor chamber 62 of the pump body 6, the rotor magnet 3 is accommodated on a cylindrical inner peripheral wall portion constituted by the lower teeth pieces 13,..., A magnetic pole formed by a plurality of lower teeth pieces 13,. The magnetic poles provided in the circumferential direction of the magnet 3 face each other (see FIGS. 1A, 1B, and 6).

  Further, the inner rotor 4 is accommodated in the pump chamber 62 of the pump body 6, and the magnetic poles of the plurality of upper teeth pieces 22, 22,... On the bottom surface 62 a of the pump chamber 62, and the magnetic poles provided in the circumferential direction of the inner rotor 4 Opposite. As a result, magnetic force is generated in two axial directions and a diametrical direction from the lower tooth piece 13 and the upper tooth piece 22 of the stator A, and the integrated rotor magnet 3 and inner rotor 4 have the magnetic force. As a result, the motor torque is improved, and the size, weight and efficiency can be improved (see FIG. 6).

  The pump cover 7 is formed of a non-magnetic metal such as a non-ferrous iron alloy and a non-ferrous metal, an aluminum alloy, or a resin, like the pump body 6, and has a suction port 71 and a discharge port 72 formed therein. A pump chamber 62 is formed which is joined by a fastener such as a bolt so as to cover the opening of the pump chamber 62 of the pump body 6 and is a closed space (see FIGS. 1A and 5). The pump cover 7 may be formed with a shaft receiving hole 73 for fixing the axial end of the shaft 8 so as not to move.

  By forming the shaft receiving hole 73, the shaft 8 is supported and fixed at both ends in the axial direction, so that a stable pumping operation can be performed without causing a vibration during the pump operation. In the electric oil pump of the present invention configured as described above, a rotating magnetic field is generated in the plurality of magnetic poles of the lower stator core 1 and the upper stator core 2 when energized, and the rotor magnet 3 and the inner rotor 4 are caused by this rotating magnetic field. Rotate.

A ... Stator, 1 ... Lower stator core, 11 ... Core body, 12 ... Stator pole,
13 ... Lower teeth piece, 2 ... Upper stator core, 22 ... Upper teeth piece,
3 ... rotor magnet, 4 ... inner rotor, 6 ... pump body, 8 ... shaft.

Claims (3)

  An electric oil pump in which a rotor magnet below an inner rotor is disposed on an inner peripheral side of a stator mounted in a pump body, and the rotor magnet is rotatably provided on a shaft mounted on the pump body. Is a stator pole formed of an insulating sintered body and projecting from the inner peripheral side of the cylindrical core body toward the center, and a lower teeth piece formed at the inner end of the stator pole A lower stator core, a coil wound around the stator pole, and an upper stator core formed at the upper end of the lower teeth piece and having an upper teeth piece, the inner rotor and the rotor magnet, A magnetic pole that is integrally formed with resin and attracts and repels the magnetic pole of the stator. Electric oil pump characterized by comprising provided a plastic magnet or the embedded magnets in over motor and the rotor magnet.   The electric oil pump according to claim 1, wherein the other end of the shaft is fixed to a pump cover that covers a pump chamber of the pump body.   3. The electric oil pump according to claim 1, wherein the outer rotor corresponding to the inner rotor is made of a nonmagnetic metal.

Images