JP2727762B2 - Brushless motor rotor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

TECHNICAL FIELD The present invention relates to a brushless motor suitable for high-efficiency and high-speed rotation, and more particularly, to a rotor thereof. (Prior Art) Generally, in a brushless motor, a permanent magnet made of ferrite or the like is disposed on an outer peripheral surface of a cylindrical rotor. For example, the conventional brushless motor 1 has a motor case (stator) 2 as shown in FIG. 6, and the motor case 2 has a cylindrical side wall 3 and a front plate closing both ends of the side wall. 4 and a rear plate 5. A plurality of excitation coils 6 are arranged inside the side wall 3 so as to form a cylindrical shape, and are fixed to the wall surface. A rotating shaft 8 is concentrically fixed to the center of the rotor (rotor) 7. The rotating shaft 8 protrudes from both ends of the rotor 7, and one end of the rotating shaft 8 is mounted on a hole 9 of the rear plate 5 of the motor case 2.
It is rotatably supported by 10. The other end of the rotating shaft 8 is rotatably supported by a bearing 12 mounted in a hole 11 of the front plate 4 of the motor case 2. An annular magnetic pole sensor support member is provided inside the side wall 3 of the motor case 2.
A plurality of magnetic pole sensors 14 are held by the support member 13 so as to be located near the surface of the rotor 7. FIG. 7 shows a conventional rotor 7. This rotor 7
The rotary shaft 8 is inserted into the cylindrical yoke 70 and the rotary shaft 8
And the yoke 70 are integrally formed. On the outer peripheral surface of the yoke 70, a pair of arc-shaped permanent magnets 71 magnetized to the N pole on the outside and the S pole on the inside, and an arc-shaped magnet magnetized to the S pole on the outside and the N pole on the inside. A pair of permanent magnets 72 are stuck alternately. In the brushless motor 1, the magnetic pole sensor
By 14, the magnetic pole position of the rotor 7 is detected, and a control circuit (not shown) supplies a current to the corresponding exciting coil 6, and the rotor 7 is rotated by the interaction between the current and the magnetic flux. The magnetic pole position of the rotated rotor 7 is detected again by the magnetic pole sensor 14, and a current is supplied to the different exciting coils 6 by the control circuit, and the rotor 7 is driven to rotate again. By repeating the above operation, the rotor 7 rotates continuously, and its rotating force is taken out of the motor via the rotating shaft 8 as power. Further, in the brushless motor 1, since the centrifugal force of the permanent magnets 71 and 72 attached to the rotor 7 is increased, as shown in FIG. Protection member 73 is provided.
The presence of permanent magnets due to the centrifugal force associated with high-speed rotation
Prevents 71 and 72 from scattering. However, in a brushless motor using a ferrite magnet, the maximum energy product is 3.3 MGOe and the residual magnetic flux density is as small as 3.8 KG. However, it is necessary to increase the permeance of the magnetic circuit, so that a large number of magnets are required, and there is a problem that the motor becomes large. Also, when used in a scroll compressor that rotates at high speed, if the stress due to the centrifugal force due to high speed rotation becomes larger than the material strength of the permanent magnet or the fixing force of the magnet to the rotor, the permanent magnet may break. , The permanent magnet may be scattered. Furthermore, when the rotor is covered with the protective member to prevent the scattering of the permanent magnet, not only does the manufacturing process of the rotor become complicated, but also the gap between the rotor and the stator substantially reduces the thickness of the protective member. As a result, the magnetic resistance increases, the magnet density decreases, and the efficiency decreases. The present invention has been made in view of the above-mentioned problems in the conventional brushless motor, and has been made to effectively solve the problem. Therefore, an object of the present invention is to provide a rotor of a brushless motor that can be configured with a small size and high efficiency and that does not break or scatter the permanent magnet even at high speed rotation. (Means for Solving the Problems) In the invention described in the first claim of the present application, a yoke is formed by a plurality of stacked silicon steel plates, and the yoke has an even number of magnetic poles on the outer periphery, and these magnetic poles are provided. In the rotor of the brushless motor in which the permanent magnet for the field is disposed in the slot, the inner peripheral surface of the yoke forming the slot, A rotor of a brushless motor having a configuration in which a protrusion that engages with the permanent magnet pressed into the slot is provided, and the tip of the protrusion presses the permanent magnet. According to the invention described in the second claim of the present application, a yoke is formed by a plurality of stacked silicon steel plates, and the yoke has an even number of magnetic poles, and these magnetic poles are used for arranging a field permanent magnet. In a rotor of a brushless motor in which a slot is provided and a permanent magnet for a field is disposed in the slot, the slot is a hole provided in a rotation axis direction,
The field permanent magnet is inserted into the hole, and a protrusion for engaging the permanent magnet pressed into the slot is provided on an inner peripheral surface of the yoke forming the slot. A brushless motor rotor configured to press the permanent magnet at the tip of the brushless motor. According to a third aspect of the present invention, in the first or second aspect of the invention, a part of the laminated plurality of silicon steel plates is depressed, and the depressed portions are depressed portions of another silicon steel plate. And a protruding portion formed by a peripheral portion of a silicon steel plate deformed by a caulking portion provided near the slot. Of the brushless motor. According to a fourth aspect of the present invention, in the first or second aspect of the invention, the projecting portion has a triangular engaging portion that engages with the permanent magnet, and a triangular base of the engaging portion. Is
The slot is formed on the inside of the yoke rather than the inner peripheral surface of the yoke forming the slot, and the both sides of the triangular shape of the engagement portion are formed with cutouts that secure the height of the projection of the engagement portion. It is a rotor of a brushless motor having a configuration continuous with the inner peripheral surface of the yoke. A fifth aspect of the present invention is the brushless motor rotor according to the first or second aspect, wherein a heat pipe is embedded in the yoke so as to be in contact with the permanent magnet. Thus, according to the present invention, the field permanent magnet is:
A portion of the surface engages the protrusion during press fit and is retained within the slot. Since the permanent magnet does not come into contact with the inner peripheral surface of the slot due to the protrusion, the friction due to the contact between the permanent magnet and the slot is small when the permanent magnet is pressed into the slot, and the permanent magnet can be pressed with a small force. Further, after the press-fitting, the outer peripheral surface of the permanent magnet engages with the protruding portion, and the permanent magnet does not fall off. When the heat pipe is embedded in the yoke so as to be in contact with the permanent magnet, the heat pipe allows the internal heat of the permanent magnet and the yoke to be released to the outside. Deterioration can be prevented. (First Embodiment) First, a first specific example will be described with reference to FIGS. 1 to 4. FIG. 1 shows a rotor 7 of this specific example, and FIG. 2 shows a cross-sectional view of the rotor 7 perpendicular to the rotation axis, not shown. The yoke 21 of the rotor 7 is integrally joined by press-fitting a plurality of silicon steel plates 22 stacked in the axial direction of the rotation shaft and press-fitting the crimped portions 23 which are embossed and depressed into a rectangle. I have. The silicon steel plate 22 is formed of a material having a high magnetic permeability, is coated with an inorganic insulating film on its surface, and has a thickness of either 0.35 mm or 0.5 mm. As shown in FIG. A pair of slots into which permanent magnets 30 and 31 are inserted into two magnetic poles 24a and 24b, each of which has four arc-shaped tips protruding radially at an angle of .ANG. 25 are provided symmetrically with respect to the center of rotation. Since the slot 25 is provided in the magnetic pole 24a, the tip and the base of the magnetic pole 24a are connected by bridges at both ends of the slot. Further, a rotation shaft opening for inserting a rotation shaft is provided at the center of the silicon steel plate 22, and a key groove is provided at a peripheral portion of the rotation shaft opening. In this specific example, the yoke 21 is formed of a laminate of silicon steel plates 22, but instead of the silicon steel plate 22, a cold-rolled steel material (SPCC material) is laminated to form the yoke 21. Is also good. In the yoke 21, a pair of permanent magnets 30 and 31 are inserted into the slots 25 with their N poles facing each other. Therefore, each of the permanent magnets 30, 31 has a structure sandwiched in the radial direction by the silicon steel plate 22, which is a material having high magnetic permeability. The N poles of the permanent magnets 30 and 31 oppose each other and repel each other, so that the magnetic pole 24a has an S pole and 24b has an N pole, and the rotor 7 has a four-pole rotor as a whole. Structure. In this specific example, a projection is provided on the inner peripheral surface of the yoke 21 forming the slot 25 to engage with the field permanent magnets 30 and 31 that are press-fitted into the slot. That is, as shown in FIG. 1 and FIG.
In the inner peripheral edge of the silicon steel plate 22 forming
5 are provided with a plurality of edges 36 protruding from two sides of the triangle. As shown in the figure, the field permanent magnets 30, 31 engage with the tip of the edge 36 when a part of the surface is press-fitted, and
25 are held inside. This edge 36 allows the permanent magnet
30 and 31 do not come into contact with the inner peripheral surface of the slot 25. Therefore, when the permanent magnets 30, 31 are press-fitted into the slot 25, friction due to contact between the permanent magnets 30, 31 and the slot 25 is small, and press-fitting can be performed with a small force. After the press-fitting, as shown in the figure, the outer peripheral surface of the permanent magnet and the tip of the edge are engaged, and the permanent magnet does not fall off. Since the permanent magnet rotor 7 of this embodiment does not hold the permanent magnets 30 and 31 inside the slot 25 with an adhesive, the permanent magnet rotor 7 may be used in a refrigerant or a pressurized fluid. Does not dissolve in the refrigerant or the pressurized fluid and the permanent magnet does not fall off. As shown in FIG. 3, the caulking portion 23 for integrally laminating the silicon steel plates 22 includes a silicon steel plate 22 forming a slot 25.
Are provided on the inner peripheral edge of the. The caulked portion is formed by pressing a mold so that a part of the silicon steel plate is depressed. By providing the caulked portion on the peripheral edge of the silicon steel plate, the peripheral edge of the silicon steel plate is deformed by the pressure of the mold, and protrudes into the slot 25 to form the edge 36 as shown in the figure. By forming the edge 36 in this manner, a part of the process for forming the edge is omitted, and the permanent magnet rotor 7 that is easier to manufacture can be obtained. FIG. 4 shows a part of a yoke in still another example of the permanent magnet rotor of this embodiment. In this example, the edge 36 of the silicon steel plate 22 has a triangular shape engaging portion that engages with a field permanent magnet (not shown).
37, and notches 38 provided on both sides of the triangular base of the engaging portion 37. The triangular base of the engagement portion 37 is provided on the inner side of the yoke 21 with respect to the inner peripheral portion of the silicon steel plate 22 forming the slot 25. This engagement portion 37
It is connected to the inner peripheral portion of the silicon steel plate forming the slot 25 via the notch 38. In order to engage the field permanent magnet, the edge projection must have a vertex angle within a predetermined angle and a predetermined height. If the vertex angle of the edge projection is too large, a large force is required for press-fitting the field permanent magnet. If the edge does not have the predetermined height, the edge is deformed by the press-fit of the field permanent magnet, and the edge does not play its role. However, providing the edge having the apex angle and the height of the above conditions on the periphery of the silicon steel plate forming the slot reduces the cross-sectional area of the field permanent magnet that can be pressed into the slot, or reduces the opening of the slot. This increases the size of the brushless motor, contradicting the demand for smaller and more efficient brushless motors. The edge 36 has the engaging portion 37 and the notch 38 so that the opening of the slot 25 is not enlarged,
Alternatively, the press-fitting of the permanent magnet is facilitated without reducing the sectional area of the field permanent magnet, and after the press-fitting, the permanent magnet is effectively engaged with the permanent magnet to prevent the permanent magnet from falling off. Although the above description has been made using the triangular-shaped edge as the projecting portion that engages with the field permanent magnet, the shape of the projecting portion is not limited to this. For example, the tip is formed in a semicircle with a small diameter. It may be a projected portion. Also, the yoke is not a laminated silicon steel sheet,
It may be formed of an integral metal, have a slot therein for press-fitting the permanent magnet for field, and further have a projection on the inner peripheral surface of the slot for engaging with the permanent magnet for field. Next, a second specific example will be described. In this specific example, a cooling structure is added to the rotor. That is, in FIG. 5, the heat pipes 19, 19 are embedded in the yoke 21 so as to be in contact with the permanent magnets 30, 31, respectively. The heat pipe 19 is filled with a working fluid, and the working fluid exchanges heat. Explaining this in detail, the heat pipe 19 that has received the heat inside the yoke from the heat receiving part inserted inside the yoke 21 exchanges heat with the outside air at the heat radiation part protruding from the yoke, and the working fluid of the heat pipe 19 is Return to the heat receiving section again. Heat pipe in this way
19 continuously releases the internal heat of the permanent magnet and yoke to the outside to cool the permanent magnet rotor. (Effects of the Invention) As described above, according to the present invention, a part of the surface of the field permanent magnet engages with the protrusion at the time of press fitting,
It is held inside the slot. Since the permanent magnet does not come into contact with the inner peripheral surface of the slot due to the protrusion, the friction due to the contact between the permanent magnet and the slot is small when the permanent magnet is pressed into the slot, and the permanent magnet can be pressed with a small force.
Also, after press-fitting, the outer peripheral surface of the permanent magnet engages with the protrusion,
The permanent magnet does not fall off. When the heat pipe is embedded in the yoke so as to be in contact with the permanent magnet, the heat pipe can release the internal heat of the permanent magnet and yoke to the outside, so the permanent magnet rotor can be cooled and the magnet is prevented from deteriorating. Is what you can do. As described above, by using the permanent magnet rotor according to the present invention, it is possible to obtain a brushless motor having a simple structure, high efficiency, and suitable for high-speed rotation. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is an exploded perspective view showing a permanent magnet rotor according to a first specific example of the present invention.

FIG. 2 is a cross-sectional view orthogonal to the rotation axis of the permanent magnet rotor of the specific example.

FIG. 3 is an enlarged cross-sectional view of a part of the yoke of the specific example, which is orthogonal to the rotation axis of the yoke.

FIG. 4 is an enlarged cross-sectional view of a part of the yoke in another example of the specific example, which is orthogonal to the rotation axis of the yoke.

FIG. 5 is a perspective view of a permanent magnet rotor according to a second specific example of the present invention.

FIG. 6 is a longitudinal sectional view showing a conventional example of a brushless motor.

FIG. 7 is a perspective view showing a conventional example of a permanent magnet rotor.

FIG. 8 is a perspective view showing a conventional example of a permanent magnet rotor having a protection member. 7 ... rotor, 21 ... yoke, 22 ... silicon steel plate, 23 ...
… Caulking part, 24a, 24b… Magnetic pole, 25… Slot, 30, 31
…… permanent magnet, 36 …… edge

Continued on the front page (31) Priority claim number Japanese Patent Application No. 3-57037 (32) Priority date Hei 3 (1991) March 20 (33) Priority claim country Japan (JP) (31) Priority claim number Special Japanese Patent Application 3-88646 (32) Priority Date Hei 3 (1991) April 19 (33) Priority claiming country Japan (JP) (31) Priority claim number Japanese Patent Application No. 3-92361 (32) Priority date Hei 3 (1991) April 23 (33) Priority claim country Japan (JP) (31) Priority claim number Japanese Patent Application No. 3-100150 (32) Priority Date Hei 3 (1991) May 1 (33) Priority Claiming country Japan (JP) (31) Priority claim number Jpn. Hei 2-121724 (32) Priority date Hei 2 (1990) November 20 (33) Priority claiming country Japan (JP) (31) Priority claim No. Jpn. No. 2-122332 (32) Priority Date Hei 2 (1990) November 21 (33) Priority Country Japan (JP) (72) Inventor Takeshi Seto 3-5-5 Yamato, Suwa City, Nagano Seiko Epson Corporation (72) Inventor Yoshihiko Yamagishi 3-3-5 Yamato, Suwa City, Nagano Prefecture Seiko Epson Shares In-house (56) References Japanese Patent Publication No. 49-33482 (JP, B1) Japanese Patent Publication No. 49-21525 (JP, B1) Japanese Utility Model Publication No. 36-29332 (JP, Y1) Jiko 30-15907 (JP, Y1)

Claims (5)

(57) [Claims] 1. A yoke is formed by a plurality of stacked silicon steel plates, and the yoke has an even number of magnetic poles on its outer periphery, and these magnetic poles are provided with slots for arranging field permanent magnets. In a rotor of a brushless motor, in which a permanent magnet for a field is disposed in the slot, a protrusion engaging with the permanent magnet pressed into the slot is formed on an inner peripheral surface of a yoke forming the slot. And a rotor of the brushless motor, wherein the tip of the projection presses the permanent magnet. 2. A yoke is formed by a plurality of stacked silicon steel sheets, the yoke has an even number of magnetic poles, and these magnetic poles are provided with slots for arranging field permanent magnets. In a rotor of a brushless motor in which a field permanent magnet is arranged in a slot, the slot is a hole provided in a rotation axis direction, and the field permanent magnet is inserted into this hole, and the slot is On the inner peripheral surface of the yoke to be formed, a projection is provided which engages with the permanent magnet which is press-fitted into the slot, and the tip of the projection presses the permanent magnet. Rotor of brushless motor. 3. A plurality of stacked silicon steel plates are partially depressed, and the depressed portions are fitted into the depressed portions of another silicon steel plate to form an integrated lamination caulking. Part
3. The brushless motor rotor according to claim 1, wherein the protruding portion is formed by a peripheral portion of a silicon steel plate deformed by a caulking portion provided near the slot. 4. The protruding portion has a triangular engaging portion that engages with the permanent magnet, and the base of the triangular shape of the engaging portion is smaller than the inner peripheral surface of the yoke forming the slot. It is provided inside, and both sides of the triangular shape of the engaging portion are continuous with the inner peripheral surface of the yoke forming the slot via a notch portion securing the height of the projection of the engaging portion. The rotor of a brushless motor according to claim 1 or 2, wherein 5. The brushless motor rotor according to claim 1, wherein a heat pipe is embedded in the yoke so as to be in contact with the permanent magnet.