JP3731581B2 - Rotating electric machine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a rotating electrical machine having a magnet fixed to the outer periphery of a rotor.
[0002]
[Prior art]
In a conventional rotor, a rotary shaft with a cylindrical yoke fixed thereto, a plurality of arc-shaped magnets fixed to the outer peripheral surface of the cylindrical yoke, and a cup-shaped cup provided with a hole fitted to the rotary shaft at the bottom. Two protective cases made of a non-magnetic material, the axial length of the yoke is made longer than the axial length of the magnet, and the protective case is disposed on the outer periphery of the yoke via an adhesive. Even if it is fitted from both sides of the rotating shaft so as to cover the magnet, it is configured so that a gap is formed at the bottom of the protective case and the axial end of the magnet, and the protective case is coated with an adhesive on the inner surface thereof, The rotary shaft is fitted from both sides of the rotary shaft so that an adhesive is interposed between the yoke and the outer surface of the magnet, and covers the surfaces. With this configuration, the force applied from both sides of the protective case is received at both ends of the yoke in the final stage, and no force is applied to the magnet (see, for example, Patent Document 1).
[0003]
[Patent Document 1]
Japanese Patent Publication No. 5-20979 (2nd page, Fig. 1)
[0004]
[Problems to be solved by the invention]
In the conventional rotor, since the cylindrical yoke is fixed to the rotating shaft, the number of parts increases, and the coaxiality of the outer peripheral surface of the cylindrical yoke with respect to the rotating shaft deteriorates. The concentricity of the magnet fixed to the surface also deteriorated, and there was a problem that the rotation balance of the rotor was deteriorated. Further, since the axial length of the yoke is longer than the axial length of the magnet, there is a problem that the adhesion position of the magnet varies and the rotational balance of the rotor deteriorates or the performance varies. Furthermore, when drilling for balancing, since it is a cup-shaped protective case, it is necessary to make a hole in the protective case as well. In addition to lowering, there was a problem that productivity was deteriorated because burrs were easily generated.
[0005]
The present invention has been made to solve the above-mentioned problems, has a small number of parts, can effectively improve the rotation balance of the rotor, is inexpensive, has high productivity, and has excellent performance. The purpose is to provide an electric machine.
[0006]
[Means for Solving the Problems]
In the rotating electrical machine according to the present invention, a cylindrical stator core, a rotor that is disposed on the inner peripheral side of the stator core and that has a shaft and whose movement in the axial direction is restricted , and the shaft are integrally formed. a yoke portion which is fixed to the outer peripheral surface of the yoke portion, a magnet having a protrusion protruding in the axial direction than both end faces in the axial direction of the stator core is integrally formed on the shaft, said magnet And a protective cover that is press-fitted into the shaft and protects the corners of the projecting portion of the magnet.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Embodiment 1 FIG.
Embodiment 1 of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view showing a motor part of a brushless motor for an electro-hydraulic power steering apparatus for a vehicle as an example of a rotating electrical machine according to the present invention, FIG. 2 is a cross-sectional view in the axial direction of the rotor, and FIG. FIG. 4 (a) is a front view of the protective cover, and FIG. 4 (b) is an AA cross-sectional view thereof. In the following description, the same or corresponding parts in the drawings are denoted by the same reference numerals. In FIG. 1, reference numeral 1 denotes a motor, and a stator 3 is fixed to the inner periphery of a frame 2 made of a steel plate by press-fitting or the like. It is arranged. The rotor 4 is rotatably supported by a bearing 6 provided on the housing 5 side made of aluminum and a bearing 7 provided on the frame 2 side. The bearing 6 is configured such that the outer ring is press-fitted and fixed to the housing 5, the rotor 4 is fixed to the inner ring of the bearing 6, and the rotor 4 is configured to be restricted from moving in the axial direction.
[0008]
In the stator 3, a coil bobbin 11 formed of nylon or the like is attached to and insulated from a cylindrical stator core 10 in which electromagnetic steel plates are laminated, and a stator coil 13 is wound around nine teeth 12. . The wire diameter of the stator coil 13 is, for example, an enamel-coated copper wire of about φ1 to φ2, and the coil terminals 14 such as the start and end of winding of the stator coil 13 are coils arranged on the side of the stator 3. A predetermined connection (for example, three-phase Y connection) is made by the connection body 15. A power supply for supplying power to the motor 1 is connected to the connection terminal 16 provided in the coil connection body 15. In addition, the engaging claw 17 provided in the coil connecting body 15 is configured to be integrated with the stator 3 by engaging the coil bobbin 11.
[0009]
1 to 4, the shaft 18 of the rotor 4 includes a yoke portion 19 that is integrally formed with the shaft 18 and forms an iron core, and is a step portion that is integrally formed with the shaft 18 and has a diameter larger than that of the yoke portion 19. 18a. One end in the axial direction of the six ferrite magnets 20 having an arc shape in cross section is in contact with the stepped portion 18a to restrict the axial position, and the magnet 20 is bonded by the adhesive applied to the outer peripheral surface of the yoke portion 19. Has been. The length of the magnet 20 in the axial direction is slightly longer than the length of the yoke portion 19 in the axial direction, and the magnet 20 protrudes slightly from the yoke portion 19 in the axial direction on the opposite side. Furthermore, the outer peripheral surface of the magnet 20 has a protruding portion 21 that extends in parallel with the inner peripheral surface of the stator core 10 and protrudes in the axial direction from both end surfaces of the stator core 10 in the axial direction. A corner 22 on the outer peripheral surface of the protrusion 21 is covered with a protective cover 23.
[0010]
Between the step portion 18 a and the yoke portion 19 that are integrally formed with the shaft 18, there is a waste portion 8. Further, a step portion 18b having a diameter smaller than that of the yoke portion 19 is provided on the side opposite to the step portion of the shaft 18, and the outer diameters of the numi portion 8, the step portions 18a and 18b, and the yoke portion 19 are all of the shaft 18. It is formed during machining, and in particular, the step portions 18a and 18b and the yoke portion 19 are formed with good coaxiality. In addition, the Nusumi portion 8 constitutes a liquid pool so that the overflowing adhesive does not protrude.
[0011]
The protective cover 23 has a dish shape as shown in FIG. 4, and has a tightening margin with respect to the outer diameters of the step portions 18 a and 18 b in order to press-fit and fix the protective cover 23 to the shaft 18 at the center. A hole 23a is provided. The hole portion 23a includes a plurality of claw portions 23b and a notch portion 23c, thereby achieving a stable press-fitting of the protective cover 23. Adhesive is applied to the inner surface side 23 d of the protective cover 23, the protective cover 23 is press-fitted along the outer diameter of the step portions 18 a and 18 b of the shaft 18, and the corner portion 22 on the outer peripheral surface of the protruding portion 21 of the magnet 20. It is fixed so as to cover. Thereafter, after the adhesive is heated and cured by a drying process, if necessary, drill cutting is performed with a drill that does not interfere with the notch 23c, and the rotation balance of the rotor 4 is adjusted, as shown in FIG. The magnet 20 is magnetized to 6 poles. The protective cover 23 is press-formed from a nonmagnetic stainless steel plate material having a thickness of 0.1 mm. FIG. 4 shows the protective cover 23 on the side opposite to the stepped portion, but the protective cover 23 on the side of the stepped portion 18a has the same shape and has a hole portion 23a having a tightening margin with respect to the outer diameter of the stepped portion 18a. It has.
[0012]
The relationship between the inner diameter dimension d of the stator 3, the outer diameter dimension D1 of the protective cover 23, and the outer diameter dimension D2 of the magnet 20 is d>D1> D2. For example, d is 47.7 mm, D1 is 47.2 mm, D2 is 46.8 mm, and the inner diameter dimension d of the stator 3 and the outer diameter dimension D2 of the magnet 20 are the same as when the protective cover 23 is not provided in the gap. The outer diameter D1 of the protective cover 23 is slightly smaller than the inner diameter d of the stator 3, and is set to a dimension that allows at least the rotor 4 to be assembled through the inner diameter of the stator 3. ing. Therefore, the dimension of the gap is reduced as compared with the case where the protective cover 23 is provided in the gap.
[0013]
Next, the operation of the first embodiment configured as described above will be described. When electric power PWM (pulse width modulation) is supplied to the connection terminal 16 from a control device (not shown), the stator coil 13 that is three-phase Y-connected by the coil connection body 15 is energized to prepare for the rotor 4. The shaft 18 is rotated by electromagnetic action with the magnet 20, and a hydraulic pump of an electric hydraulic power steering device (not shown) is driven by the rotational force, and the steering force of the steering can be assisted by the hydraulic pressure. Note that the brushless motor for the electrohydraulic power steering apparatus has a voltage of 12 V, about 50 to 100 A, 4500 r / min. There is a need for a motor that is used in a certain degree, and that is particularly excellent in safety, responsiveness, and quietness, and that is small, high-performance and inexpensive.
[0014]
The first embodiment is configured as described above, and includes the yoke portion 19 formed integrally with the shaft 18, can be processed simultaneously with the shaft 18, has good productivity, and the outer peripheral surfaces of the shaft 18 and the yoke portion 19. Since the magnet 20 is fixed to the outer peripheral surface of the magnet 20 and the outer peripheral surface of the magnet 20 and the coaxiality of the protective cover 23 are good, the rotation balance can be effectively improved. Compared with the case where the separate yoke portion 19 is fixed to the shaft 18, the number of parts is also reduced. Similarly, since the step portions 18a and 18b formed integrally with the shaft 18 are provided, the shaft 18 can be processed simultaneously, and one end of the magnet 20 in the axial direction is brought into contact with the step portion 18a, so that the axial direction of the magnet 20 is increased. In addition to easy positioning and good assembly, the rotation balance can also be improved. Furthermore, the protective cover 23 is easily press-fitted along the step portions 18a and 18b, and the corner portion 22 of the magnet 20 that is particularly susceptible to breakage or cracking can be covered by the protective cover 23. Further, since the press fitting is performed, the position of the protective cover 23 is determined, and the protective cover 23 does not move even when the adhesive is dried.
[0015]
Since the protective cover 23 is press-fitted along the stepped portion 18a having good coaxiality with the outer peripheral surface of the magnet 20, it can be easily press-fitted so as to cover the corner portion 22 of the magnet 20, and the workability is good and the rotation balance is also good. Can be improved.
[0016]
Since the waste portion 8 is provided between the step portion 18 a and the yoke portion 19, the adhesive protruding from the adhesive surface accumulates in the waste portion 8, so that the protruding adhesive interferes with the inner peripheral surface of the stator core 10. It is possible to improve the performance of the motor 1 by reducing the size of the gap so that no noise is generated and the adhesive does not protrude.
[0017]
Since the axial length of the magnet 20 is longer than the axial length of the yoke portion 19, a slight gap is formed between the yoke portion 19 and the protective cover 23, and the adhesive protruding from the adhesive surface is Since the accumulated adhesive does not interfere with the inner peripheral surface of the stator core 10 to generate noise, and the gap size is reduced by the amount that the adhesive does not protrude, thereby improving the performance of the motor 1. Can be improved.
[0018]
Since the protruding portion 21 of the magnet 20 is protected by the protective cover 23, the protective cover 23 is small and inexpensive and has good assembly properties, and the rotor 4 has a small rotational unbalance and inertia, and eddy current loss is reduced and performance is improved. The rotating electric machine can be reduced in size. In particular, when PWM is performed, the effect of reducing eddy current loss is great. Furthermore, since the gap can be reduced as compared with the case where the protective cover 23 is disposed in the gap, the performance of the rotating electrical machine can be improved and the size can be reduced. In addition, since the rotor 4 is provided with an axial direction movement restricting means for restricting movement in the axial direction, the rotor 4 moves and the protective cover 23 moves into the gap and does not come into contact with the stator 3. In particular, in ferrite, the corner portion 22 is likely to be damaged or cracked, and the corner portion 22 is covered with the protective cover 23, so that the magnet 20 can be effectively prevented from being damaged or cracked. Moreover, since it was set as the cap shape, the lifting and scattering of the magnet 20 by centrifugal force can be prevented.
[0019]
Since the protective cover 23 is bonded, the magnet 20 can be more effectively prevented from being lifted or scattered due to breakage, cracking or centrifugal force of the magnet 20, and the protective cover 23 moves in the axial direction and does not come into contact with the non-rotating portion. A low noise and safe rotating electrical machine can be obtained.
[0020]
Since the protective cover 23 has a notch 23c having a size that does not interfere with the drill during drill cutting for adjusting the rotational balance of the rotor 4, the force of the drill does not act on the protective cover 23. In addition to the deformation and adhesive force of the protective cover 23 not being reduced, the protective cover 23 is not burred, the chips are discharged well, and a rotating electrical machine excellent in workability, quietness and safety can be obtained.
[0021]
The motor for the electro-hydraulic power steering device is particularly required to have a fast start-up characteristic and excellent safety. By using the rotating electrical machine of the present invention, it is preferable for the electro-hydraulic power steering device. A motor can be obtained. In particular, since the protective cover 23 is mounted on the protruding portion 21 of the magnet 20, the inertia is small and the rotation rising characteristic is good. In addition, since the Nusumi portion 8 is provided, the overflowing adhesive does not interfere with the inner peripheral surface and the like of the stator core 10 and the cutout portion 23c is provided, so that the deformation and adhesive force of the protective cover 23 are reduced. In addition, it is possible to obtain a motor for an electrohydraulic power steering device that is low in noise and excellent in safety, such as good chip discharge.
[0022]
Further, since the magnet 20 is magnetized after the protective cover 23 is disposed, there is no magnetic force before the protective cover 23 is disposed, and no debris or foreign matter adheres to the magnet 20 to improve reliability and protect the magnet 20. The magnet 20 can be prevented from being broken or cracked in a magnetizing process or an assembling process after the cover 23 is disposed. In particular, it is possible to obtain a rotating electrical machine with low noise and excellent safety that is suitable for a motor for an electrohydraulic power steering apparatus.
[0023]
Embodiment 2. FIG.
A second embodiment of the present invention will be described with reference to FIGS. 5 is a sectional view in the axial direction of the rotor, FIG. 6 is a sectional view in the radial direction of the rotor, FIG. 7A is a front view of the protective cover, and FIG. . The shaft 18 of the rotor 4 includes a yoke portion 19 that is integrally formed with the shaft 18 and forms an iron core, and also includes step portions 18 a and 18 b that are integrally formed with the shaft 18. One end in the axial direction of the three ferrite magnets 20 having an arc shape in cross section is in contact with the stepped portion 18a to restrict the axial position, and the magnet 20 is bonded by the adhesive applied to the outer peripheral surface of the yoke portion 19. Has been. The length of the magnet 20 in the axial direction is slightly longer than the length of the yoke portion 19 in the axial direction, and the magnet 20 has a dimension that slightly protrudes from the yoke portion 19 in the axial direction on the opposite step side.
[0024]
Between the step portion 18a and the yoke portion 19 that are integrally formed with the shaft 18, there is a waste portion 8 formed by chamfering the corner portion of the magnet 20. The Nusumi part 8 is formed when the magnet 20 is processed, and constitutes a liquid pool of the protruding adhesive.
[0025]
The protective cover 23 is composed of a cup-shaped piece as shown in FIG. 7, and has an outer diameter of the step portion 18b in order to press-fit and fix the protective cover 23 to the step portion 18b of the shaft 18 at the center. On the other hand, a hole 23a having a tightening margin is provided. The hole portion 23a includes a plurality of claw portions 23b and a notch portion 23c so that the protective cover 23 can be stably press-fitted. Furthermore, a hole-shaped notch 23e that does not interfere with the rotation balance adjusting drill is provided, and drilling is performed through the notch 23e. An adhesive is applied to the inner surface 23 d of the protective cover 23, and the protective cover 23 is press-fitted and bonded so that the corner portion 22 on the outer peripheral surface of the protruding portion 21 is covered with the protective cover 23. Thereafter, after the adhesive is heated and cured by a drying process, if necessary, drill cutting is performed with a drill that does not interfere with the notch 23e, and the rotation balance of the rotor 4 is adjusted, as shown in FIG. The magnet 20 is magnetized to 6 poles.
[0026]
Since the second embodiment is configured as described above, it includes a yoke portion 19 formed integrally with the shaft 18, and as in the first embodiment, the rotational balance can be effectively improved and the number of parts can be increased. Decrease. Similarly, since the step portion 18a formed integrally with the shaft 18 is provided, the axial position of the magnet 20 can be easily positioned and the rotation balance can be improved as in the first embodiment. Furthermore, since the protective cover 23 is press-fitted into the stepped portion 18b, the press-in position of the protective cover 23 is easy and the press-fitting position is determined, and the protective cover 23 does not move even when the adhesive is dried.
[0027]
Since the nosumi part 8 configured by chamfering the corners of the magnet 20 is provided between the step part 18a and the yoke part 19, the nosumi part 8 can be easily configured and the same effect as in the first embodiment can be obtained. . Further, since the length of the magnet 20 in the axial direction is longer than the length of the yoke portion 19 in the axial direction, the same effect as in the first embodiment can be obtained.
[0028]
Since the corner portion 22 of the magnet 20 is covered with the protective cover 23, breakage and cracking of the magnet 20 can be effectively prevented. The corner 22 on the side of the step 18 a is protected by the step 18 a and the protective cover 23. Moreover, since it was cup-shaped, it is possible to reliably prevent the magnet 20 from being lifted or scattered by centrifugal force, and it can be applied to a rotating electrical machine having a high rotation speed.
[0029]
Since the magnet 20 is composed of a plurality of arc-shaped magnets and magnetized to a plurality of magnetic poles per magnet, the magnet 20 is compared with the case where the magnet 20 is composed of six arc-shaped magnets as shown in FIG. Since the number of the magnets is small, breakage and cracking of the magnet 20 during assembly can be prevented more effectively, the cost of the magnet 20 can be reduced, and the assemblability can be improved. Further, since it has an arc shape, it can be easily manufactured and has good dimensional accuracy, and the coaxiality of the outer peripheral surface of the magnet 20 after assembly can be further improved. In the case of three arcs, the angle of one arc is 120 degrees. However, in determining the number of magnets 20, the number of arcs is such that the angle of one arc is approximately 120 degrees or less. Therefore, the productivity and dimensional accuracy of the magnet 20 can be improved, and an inexpensive rotating machine with good performance can be obtained.
[0030]
Since the protective cover 23 is adhered, the magnet 20 can be reliably prevented from being broken or cracked, and the magnet 20 can be prevented from being lifted or scattered by centrifugal force, and the protective cover 23 is moved and does not come into contact with the non-rotating portion.
[0031]
Since the protective cover 23 has a hole-shaped notch 23e having a size that does not interfere with the drill during drill cutting for adjusting the rotational balance of the rotor 4, the same effect as in the first embodiment is obtained. be able to. In particular, since the notch portion 23c is also provided, the chips are more easily discharged.
[0032]
In the above, the brushless motor for an electrohydraulic power steering apparatus has been described as the rotating electrical machine, but the rotating electrical machine may be a generator or a generator motor.
[0033]
【The invention's effect】
As described above, the present invention is integrally formed with the cylindrical stator core, the rotor that is disposed on the inner peripheral side of the stator core and has a shaft that is restricted from moving in the axial direction, and the shaft. a yoke portion which is fixed to the outer peripheral surface of the yoke portion, a magnet having a protrusion protruding in the axial direction than both end faces in the axial direction of the stator core is integrally formed on the shaft, said magnet The step of positioning one of the magnets in contact with one end in the axial direction of the magnet and the protective cover that press-fits the shaft and protects the corners of the protruding portion of the magnet, the number of parts is small and effective. In addition to improving the rotation balance of the rotor, it is possible to obtain a rotating electrical machine that is excellent in productivity, inexpensive and excellent in performance.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a motor portion of a brushless motor for an electro-hydraulic power steering device showing Embodiment 1 of the present invention.
FIG. 2 is a sectional view in the axial direction of a rotor showing Embodiment 1 of the present invention.
FIG. 3 is a radial sectional view of a rotor showing Embodiment 1 of the present invention.
FIG. 4 is a front view of a protective cover showing Embodiment 1 of the present invention and an AA cross-sectional view thereof.
FIG. 5 is a sectional view in the axial direction of a rotor showing a second embodiment of the present invention.
FIG. 6 is a radial sectional view of a rotor showing a second embodiment of the present invention.
FIGS. 7A and 7B are a front view and a BB sectional view of a protective cover showing Embodiment 2 of the invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Motor (rotary electric machine), 3 Stator, 4 Rotor, 8 Nusumi part, 10 Stator core, 18 Shaft, 18a Step part, 19 York part, 20 Magnet, 21 Protruding part, 22 Corner | angular part, 23 Protective cover, 23a hole part, 23b claw part, 23c notch part, 23e notch part.

Claims (8)

A cylindrical stator core, a rotor having a shaft disposed on the inner peripheral side of the stator core and restricted in axial movement, a yoke portion integrally formed with the shaft, and the yoke portion fixed to the outer peripheral surface of said magnet having a protrusion protruding in the axial direction than both end faces in the axial direction of the stator core, are integrally formed on the shaft, one axial end of the magnet is in contact with the A rotating electrical machine comprising: a step portion for positioning a magnet; and a protective cover that is press-fitted into the shaft and protects a corner portion of the protruding portion of the magnet.   The rotating electrical machine according to claim 1, wherein the protective cover is press-fitted into the stepped portion.   The rotating electrical machine according to claim 1, wherein a bump portion is provided between the step portion and the yoke portion.   The rotating electrical machine according to any one of claims 1 to 3, wherein a length of the magnet in the axial direction is longer than a length of the yoke portion in the axial direction.   The rotating electrical machine according to any one of claims 1 to 4, wherein the magnet is formed of a plurality of arcs and is magnetized with a plurality of magnetic poles per magnet.   The rotating electrical machine according to any one of claims 1 to 5, wherein the protective cover is bonded.   The rotating electrical machine according to any one of claims 1 to 6, wherein the protective cover has a notch portion that does not interfere with the drill during drill cutting for adjusting the rotation balance of the rotor.   The rotating electrical machine according to claim 1, wherein the rotating electrical machine is used in a motor for an electrohydraulic power steering apparatus.

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