JP2009171685A - Electric motor and electric pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric motor wherein a permanent magnet is securely fixed on an axial member without use of adhesive. <P>SOLUTION: The electric motor M includes a stator 3 and a rotor 6 disposed inside the stator 3 and is so constructed that a rotating magnetic field is produced by the stator 3 and the rotor 6 is thereby rotated. The rotor 6 includes: a permanent magnet 6a for obtaining driving force for the rotor 6 to rotate by the rotating magnetic field; and two axial members 6b, 6c provided at both ends 6A, 6B of the permanent magnet 6a in the axial direction A. The permanent magnet 6a is sandwiched between the two axial members 6b, 6c. As a result, the permanent magnet 6a is clamped between the two axial members 6b, 6c and the permanent magnet 6a is fixed against the axial members 6b, 6c. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electric motor including a permanent magnet for obtaining torque for rotating a rotor, and an electric pump including the electric motor.

  2. Description of the Related Art In recent years, attention has been drawn to electric vehicles that run by the output of an electric motor and hybrid vehicles that run by the output of an engine and an electric motor. In such automobiles such as electric vehicles and hybrid vehicles, an electric pump is used as a hydraulic source in order to supply hydraulic pressure to a transmission and the like, and such an electric pump includes a small electric motor as a driving source. ing.

  As the electric motor, there is known a so-called inner rotor type motor that includes a stator and a rotor disposed inside the stator, and generates a rotating magnetic field by the stator to rotate the rotor. Further, as the electric motor, it is known to use a brushless motor that does not require a commutator by using a permanent magnet as a rotor field.

Generally, in an inner rotor type brushless motor, a rotor includes a permanent magnet and a shaft member, and the permanent magnet is attached to the shaft member. More specifically, the rotor includes a cylindrical permanent magnet and a shaft member provided inside the permanent magnet, the cylindrical permanent magnet is fitted into the shaft member, and the shaft member and the permanent magnet are bonded to each other by an adhesive. The thing which fixed the permanent magnet with respect to the shaft member by adhere | attaching using is known (for example, refer patent document 1).
JP 2002-209352 A

  However, since the electric pump is mounted on a vehicle of an automobile, the usage environment of the electric motor included in the electric pump is severe, and the adhesive force for bonding the shaft member and the permanent magnet tends to decrease with time. As a result, the adhesive may peel off from the shaft member or the permanent magnet. That is, there is a problem that the permanent magnet may not be fixed to the shaft member due to deterioration of the adhesive.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide an electric motor capable of securely fixing a permanent magnet to a shaft member without using an adhesive, and an electric pump including the same. Is to provide.

  The invention described in claim 1 is an electric motor that includes a stator and a rotor disposed inside the stator, and that rotates the rotor by generating a rotating magnetic field by the stator. The rotor is rotated by the rotating magnetic field. A permanent magnet for obtaining a driving force to be driven, and two shaft members provided at both ends of the permanent magnet in the axial direction. By sandwiching the permanent magnet between the two shaft members, the two shaft members are made permanent. A magnet is sandwiched and a permanent magnet is fixed to the shaft member.

  According to the same configuration, the rotor includes the permanent magnet and two shaft members provided at both ends of the permanent magnet in the axial direction, and the two magnet members sandwich the permanent magnet between the two shaft members. A permanent magnet is clamped and the permanent magnet is fixed to the shaft member. For this reason, a permanent magnet can be reliably fixed with respect to a shaft member, without using an adhesive agent by pinching a permanent magnet from the both ends in an axial direction with two shaft members. In addition, since it is not necessary to use an adhesive, the cost can be reduced. The axial direction is a direction parallel to the central axis of the rotor.

  The invention according to claim 2 is the electric motor according to claim 1, wherein the permanent magnet and the shaft member are each formed with an engaging portion, and are formed in each of the permanent magnet and the shaft member. When the engaging portions engage with each other, the movement of the permanent magnet in the direction orthogonal to the axial direction is restricted, and the permanent magnet is locked to the shaft member.

  According to this configuration, the engagement portions formed on each of the permanent magnet and the shaft member engage with each other, so that the movement of the permanent magnet in the direction orthogonal to the axial direction is restricted, and the shaft member is The permanent magnet is locked. For this reason, the permanent magnet can be more securely fixed to the shaft member than when the permanent magnet is simply sandwiched between the two shaft members.

  Invention of Claim 3 is an electric motor of Claim 1, Comprising: A through-hole is formed in a permanent magnet and a shaft member, respectively, The through-hole formed in each of a permanent magnet and a shaft member By inserting the engaging member, the movement of the permanent magnet in the direction orthogonal to the axial direction is restricted, and the permanent magnet is locked to the shaft member.

  According to this configuration, by inserting the engaging member into the through hole formed in each of the permanent magnet and the shaft member, the movement of the permanent magnet in the direction orthogonal to the axial direction is restricted, and the shaft member is The permanent magnet is locked. For this reason, the permanent magnet can be more securely fixed to the shaft member than when the permanent magnet is simply sandwiched between the two shaft members. Further, since it is sufficient that through holes are formed in the permanent magnet and the shaft member, it is easier to form the permanent magnet and the shaft member than in the case where the engaging portion having a complicated shape is formed in the permanent magnet and the shaft member. Can be done.

According to a fourth aspect of the present invention, the electric motor according to any one of the first to third aspects is provided as a drive source.
According to this configuration, since the electric motor of the present invention is provided as a drive source, the same effect as that of the invention described in any one of claims 1 to 3 can be obtained.

  According to the present invention, the permanent magnet can be securely fixed to the shaft member without using an adhesive, and the cost can be reduced.

  Embodiments according to the present invention will be described below with reference to FIGS. 1 and 2. An arrow A in the figure indicates an axial direction that is parallel to the central axis of the rotor, and an arrow R in the figure indicates a direction orthogonal to the axial direction A.

  The electric motor M, which is an inner rotor type brushless motor according to the present embodiment, is a drive source of the electric pump U. The electric pump U generates a rotating magnetic field by the stator 3 and rotates the rotor 6. A gear pump (gear pump) P for transporting fluid by rotating the gear 7 by the rotation of the rotor 6 is integrated.

  More specifically, the bottomed substantially cylindrical motor case 1 houses the stator 3 constituting the electric motor M and the like, and the pump housing 2 is fixed to the opening end 1A of the motor case 1. ing. Therefore, the motor case 1 is sealed by the pump housing 2.

  A substantially cylindrical stator 3 that generates a rotating magnetic field is press-fitted or bonded to the inner periphery 1 </ b> B of the motor case 1. The stator 3 includes a stator core 3a and a plurality of coils 3b made of conductive wires wound around the stator core 3a, and can generate a rotating magnetic field by appropriately supplying electricity to the coil 3b.

  A bearing housing 1 a for housing the rolling bearing 4 is formed on the bottom 1 C in the motor case 1, and the end 2 A of the pump housing 2 in the axial direction A is also the same as the motor case 1. A bearing housing portion 2a for housing the rolling bearing 5 is formed.

  A rotor 6 composed of a permanent magnet 6a and two shaft members 6b, 6c is disposed inside the annular stator 3, and the rotor 6 is rolled in the bearing housing portions 1a, 2a. The bearings 4 and 5 are rotatably supported.

  More specifically, the rotor 6 includes a permanent magnet 6a for obtaining a driving force for rotating the rotor 6 by a rotating magnetic field, and two shaft members 6b provided at both ends 6A and 6B of the permanent magnet 6a in the axial direction A. , 6c.

  The permanent magnet 6a is formed in a columnar shape, and magnetic poles are alternately magnetized along the direction in which the rotor 6 rotates on the outer periphery 6S of the permanent magnet 6a, so that a rotating magnetic field is generated by the stator 3. Thus, the rotor 6 (that is, the permanent magnet 6a and the shaft members 6b and 6c) is rotated.

  Further, by sandwiching the permanent magnet 6 a between the two shaft members 6 b and 6 c, the permanent magnet 6 a is sandwiched between the two shaft members 6 b and 6 c, and one shaft member 6 c is supported by the rolling bearing 5. At the same time, the other shaft member 6b is supported by the rolling bearing 4, so that the rotor 6 is rotatably supported.

  As described above, the motor case 1 houses the stator 3, the permanent magnet 6a of the rotor 6, and the rolling bearings 4 and 5, and the electric motor M includes the stator 3 and the rotor 6. The gear pump P is driven using the rotor 6 as a drive shaft (that is, the gear 7 of the gear pump P is rotated).

  The pump housing 2 is formed with a gear housing portion 2 b for housing the gear 7, and a through hole 2 c is provided at the center of the pump housing 2. One shaft member 6c is inserted into the through hole 2c, and the shaft member 6c extends from the motor case 1 to the gear housing portion 2b.

  The recessed gear housing portion 2b houses an inner rotor (external gear) 7a and an outer rotor (internal gear) 7b, which are gears 7 using a trochoidal curve as a tooth shape. The shaft member 6c is fixed.

  The gear housing portion 2b in which the gear 7 is housed is sealed by a pump plate 8 that covers the end surface 2B of the pump housing 2, and the pump plate 8 has a suction for sucking fluid oil into the gear housing portion 2b. A port (not shown) and a discharge port (not shown) for discharging oil from the gear housing 2b are formed.

  As described above, the gear 7 is accommodated in the pump housing 2 sealed by the pump plate 8, and the gear pump P includes the pump housing 2, the gear 7, the pump plate 8, and the rotor 6. By driving the gear 7 in the pump housing 2 by the rotation, the oil is transported from the suction port of the pump plate 8 to the discharge port.

  Here, in the present embodiment, as described above, the rotor 6 includes the permanent magnet 6a for obtaining a rotating driving force and the two shaft members 6b and 6c provided at both ends 6A and 6B of the permanent magnet 6a. I have. Then, by sandwiching the permanent magnet 6a between the two shaft members 6b and 6c, the permanent magnet 6a is sandwiched between the two shaft members 6b and 6c, and the permanent magnet 6a is fixed to the shaft members 6b and 6c. It is characterized in that it is. With this configuration, the permanent magnet 6a is sandwiched between the two shaft members 6b and 6c from both ends 6A and 6B in the axial direction A.

  In the present embodiment, the permanent magnet 6a and the shaft members 6b and 6c are each formed with an engaging portion 6d, and the permanent magnet 6a and the engaging members 6d formed on each of the shaft members 6b and 6c. Are engaged with each other, the movement of the permanent magnet 6a in the direction R perpendicular to the axial direction A is restricted, and the permanent magnet 6a is locked to the shaft members 6b and 6c.

  More specifically, as shown in FIG. 2, engaging projections 6e and 6f, which are engaging portions 6d, are formed at both ends 6A and 6B of the permanent magnet 6a, respectively, and shaft members 6b and 6c. The permanent magnet side end portions 6D and 6E are respectively formed with engaging recesses 6g and 6h which are engaging portions 6d. When the permanent magnet 6a is sandwiched between the two shaft members 6b and 6c, the engaging convex portion 6e of the permanent magnet 6a and the engaging concave portion 6g of the shaft member 6b are engaged with each other and permanently The engaging projection 6f of the magnet 6a and the engaging recess 6h of the shaft member 6c are engaged with each other. For this reason, the movement of the permanent magnet 6a in the direction R orthogonal to the axial direction A is restricted, and the permanent magnet 6a is locked to the shaft members 6b and 6c.

According to the electric motor M of the above embodiment, the following effects can be obtained.
(1) In the electric motor M that includes the stator 3 and the rotor 6 disposed inside the stator 3 and rotates the rotor 6 by generating a rotating magnetic field, the rotor 6 is rotated by the rotating magnetic field. A permanent magnet 6a for obtaining a driving force and two shaft members 6b and 6c provided at both ends 6A and 6B of the permanent magnet 6a in the axial direction A are provided. Then, by sandwiching the permanent magnet 6a between the two shaft members 6b and 6c, the permanent magnet 6a is sandwiched by the two shaft members 6b and 6c, and the permanent magnet 6a is fixed to the shaft members 6b and 6c. Therefore, the permanent magnet 6a can be sandwiched between the two shaft members 6b and 6c from both ends 6A and 6B in the axial direction A. Therefore, the permanent magnet 6a can be reliably fixed to the shaft members 6b and 6c without using an adhesive. In addition, since it is not necessary to use an adhesive, the cost can be reduced.

  (2) The permanent magnet 6a and the shaft members 6b and 6c are respectively formed with engaging portions 6d, and the permanent magnet 6a and the engaging portions 6d formed on the shaft members 6b and 6c are engaged with each other. Thus, the movement of the permanent magnet 6a in the direction R perpendicular to the axial direction A is restricted, and the permanent magnet 6a is locked to the shaft members 6b and 6c. For this reason, the permanent magnet 6a can be more securely fixed to the shaft members 6b and 6c than when the permanent magnet 6a is simply sandwiched between the two shaft members 6b and 6c.

  Moreover, in this embodiment, since the electric pump U is equipped with the electric motor M that can obtain the effects (1) and (2) as a drive source, it is the same as the above (1) and (2). An effect can be obtained.

  In addition, this invention is not limited to the said embodiment, A various design change is possible based on the meaning of this invention, and they are not excluded from the scope of the present invention. For example, you may change the said embodiment as follows.

  In the above embodiment, the engaging convex portions 6e and 6f are formed at both ends 6A and 6B of the permanent magnet 6a, and the engaging concave portions 6g and 6h are formed at the permanent magnet side end portions 6D and 6E of the shaft members 6b and 6c. However, irregularities such as the engaging convex portions 6e and 6f and the engaging concave portions 6g and 6h may be appropriately changed. That is, engagement concave portions that are engaging portions 6d are formed at both ends 6A and 6B of the permanent magnet 6a, and engagement portions 6d that are engaging portions 6d are provided at the end portions 6D and 6E of the shaft members 6b and 6c. A convex portion may be formed.

  -In above-mentioned embodiment, although the engaging part 6d was formed in the permanent magnet 6a and the shaft members 6b and 6c, respectively, the engaging part 6d was not formed in the permanent magnet 6a and the shaft members 6b and 6c. Also good. That is, if the permanent magnet 6a can be held by the two shaft members 6b and 6c by sandwiching the permanent magnet 6a between the two shaft members 6b and 6c, the effect (1) can be obtained. In this case, it goes without saying that the permanent magnet 6a is held between the two shaft members 6b and 6c so that the permanent magnet 6a does not move in the direction R perpendicular to the axial direction A even when the rotor 6 rotates.

  In addition, instead of restricting the movement of the permanent magnet 6a in the direction R perpendicular to the axial direction A by engaging the engaging portions 6d formed on the permanent magnet 6a and the shaft members 6b and 6c with each other. The movement of the permanent magnet 6a in the direction R orthogonal to the axial direction A may be restricted using an engaging member.

  More specifically, as shown in FIGS. 3 and 4, the permanent magnet 6a and the shaft members 6b and 6c are formed with through-holes 6i and 6j extending in the axial direction A, respectively, and the permanent magnet 6a and the shaft member 6b. , 6c, rod-shaped pins 9 as engaging members are inserted into the through holes 6i, 6j formed in the respective ones. By inserting the pin 9 into the through holes 6i and 6j in this way, the movement of the permanent magnet 6a in the direction R perpendicular to the axial direction A is restricted, and the permanent magnet 6a is engaged with the shaft members 6b and 6c. It may be stopped. In this case, the pin 9 is press-fitted into at least one of the through holes 6 i and 6 j and is fixed to the rotor 6.

  If comprised in this way, the permanent magnet 6a can be more reliably fixed with respect to the shaft members 6b and 6c compared with the case where the permanent magnet 6a is pinched | interposed only with two shaft members 6b and 6c. Moreover, since it is sufficient that the through holes 6i and 6j are formed in the permanent magnet 6a and the shaft members 6b and 6c, when the engaging portion 6d having a complicated shape is formed in the permanent magnet 6a and the shaft members 6b and 6c. In comparison, the permanent magnet 6a and the shaft members 6b and 6c can be easily formed.

  In the case where the movement of the permanent magnet 6a in the direction R perpendicular to the axial direction A is restricted using the pin 9 which is the engagement member described in the above modification, as shown in FIG. It is desirable that a gap 9A is formed between the pin 9 and the through hole 6i formed in the permanent magnet 6a. In this case, the pin 9 is press-fitted into the through hole 6j formed in the shaft members 6b and 6c and is fixed to the rotor 6.

  If comprised in this way, since the clearance gap 9A is formed between the pin 9 inserted in the through holes 6i and 6j and the through hole 6i formed in the permanent magnet 6a, the electric motor M is used. Thus, even when the permanent magnet 6a is thermally expanded, unnecessary stress can be prevented from being generated in the permanent magnet 6a by the pin 9, and the permanent magnet 6a can be prevented from being damaged.

  In the above embodiment, the engaging portions 6d (that is, the engaging convex portions 6e and 6f) are formed at the both ends 6A and 6B of the permanent magnet 6a, but the engaging portions are only at one of the both ends 6A and 6B. 6d may be formed. Similarly, in the above modification, the through-hole 6j is formed in the two shaft members 6b and 6c as shown in FIG. 3, but the through-hole 6j may be formed in only one of the shaft members 6b and 6c. Good.

Next, the technical idea that can be grasped from the above embodiment will be described below together with the effects thereof.
(Additional remark 1) The clearance gap is formed between the said engaging member and the said through-hole formed in the said permanent magnet, The electric motor of Claim 3 characterized by the above-mentioned.

  According to this configuration, a gap is formed between the engagement member inserted into the through hole and the through hole formed in the permanent magnet, so that the permanent magnet is thermally expanded by using the electric motor. Even in this case, unnecessary stress can be prevented from being generated in the permanent magnet by the engaging member, and the permanent magnet can be prevented from being damaged.

The schematic block diagram which shows the electric pump provided with the electric motor which concerns on embodiment of this invention. The disassembled perspective view which shows the rotor of the electric motor which concerns on embodiment of this invention. The schematic block diagram which shows the electric pump provided with the electric motor which concerns on the modification of this invention. The disassembled perspective view which shows the rotor of the electric motor which concerns on the modification of this invention.

Explanation of symbols

  A ... Axial direction (direction parallel to the central axis of the rotor), R ... direction orthogonal to the axial direction, M ... electric motor, P ... gear pump, U ... electric pump, 1 ... motor case, 2 ... pump housing, 3 ... stator, 4, 5 ... rolling bearing, 6 ... rotor, 6a ... permanent magnet, 6b, 6c ... shaft member, 6d ... engagement part, 6e, 6f ... engagement convex part (engagement part), 6g, 6h ... Engaging recess (engaging part), 6i, 6j ... through hole, 6A, 6B ... both ends of the permanent magnet, 6D, 6E ... permanent magnet side end of the shaft member, 7 ... gear, 8 ... pump plate, 9 ... pin (Engagement member), 9A: gap.

Claims (4)

An electric motor comprising a stator and a rotor disposed inside the stator, wherein the stator generates a rotating magnetic field and rotates the rotor.
The rotor includes a permanent magnet for obtaining a driving force for rotating the rotor by the rotating magnetic field, and two shaft members provided at both ends of the permanent magnet in the axial direction,
By sandwiching the permanent magnet between the two shaft members, the permanent magnet is sandwiched by the two shaft members, and the permanent magnet is fixed to the shaft member. Electric motor.   The permanent magnet and the shaft member are each formed with an engaging portion, and the engaging portions formed on the permanent magnet and the shaft member are engaged with each other, thereby being orthogonal to the axial direction. The electric motor according to claim 1, wherein movement of the permanent magnet in a direction is restricted and the permanent magnet is locked to the shaft member.   A through hole is formed in each of the permanent magnet and the shaft member, and by inserting an engaging member into the through hole formed in each of the permanent magnet and the shaft member, the direction is perpendicular to the axial direction. The electric motor according to claim 1, wherein movement of the permanent magnet is restricted and the permanent magnet is locked to the shaft member.   An electric pump comprising the electric motor according to any one of claims 1 to 3 as a drive source.

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