JP4565780B2 - Manufacturing method of electric compressor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing an electric compressor mounted on a refrigerator-freezer or the like.
[0002]
[Prior art]
An electric motor part constituting this type of electric compressor is a DC (direct current) motor constituted by a stator in which windings are housed and a rotor in which a permanent magnet is mounted. There are two types of DC motors: a surface magnet type (SMP method) in which a permanent magnet is mounted on the outer periphery of the rotor, and an embedded magnet type (IMP method) in which a permanent magnet is embedded inside the rotor. An embedded magnet type that can effectively use magnetic flux has been increasingly used.
[0003]
Generally, in order to increase the efficiency of an electric motor, it is necessary to increase the amount of magnetic flux of a magnet. Therefore, in the embedded magnet type, in order to increase the cross-sectional area of the magnet as much as possible, there is a device that does not provide means for positively fixing or holding the permanent magnet while it is inserted into the permanent magnet hole. For this reason, the permanent magnet may vibrate during operation to generate noise, and the increase in noise becomes a serious problem in refrigeration equipment typified by household refrigerators.
[0004]
FIG. 3 is a plan view of the rotor of a conventional electric compressor for suppressing this noise as seen from the axial direction and a longitudinal sectional view thereof. In the figure, the rotor 30 is formed by laminating ferromagnetic steel plates, and each steel plate has a hole through which the main shaft passes at the center, and a plurality of (four shown) are provided around the hole. Permanent magnet holes 33 are formed, and these are integrally fastened and fixed in the axial direction by rivets 31. Then, a pair of left and right slit openings 36 are formed on the inner side in the radial direction of each permanent magnet hole 33, and the radial outer wall of the slit opening 36 is extended toward the permanent magnet hole 33 side. The permanent magnet 32 inserted into the permanent magnet hole 33 is pressed radially outward to hold it.
[0005]
Note that the axial center portion of the rotor 30 described above is formed by a fitting portion 34 having a small inner diameter and a counter bore portion 35 having a radius R ₁ larger than this and a length L ₁ adjacent to each other in the axial direction. A main shaft (not shown) is inserted into the fitting portion 34, and a slit-like opening 36 is formed outside the counter bore portion 35.
[0006]
[Problems to be solved by the invention]
However, in the rotor 30 shown in FIG. 3, the radial width of the permanent magnet hole 33 is limited because it is necessary to provide a plurality of slit-like openings 36 between the counterbore part 35 and the slit-like openings 36. For this reason, the thickness of the permanent magnet in the radial direction is limited, and the magnet area is reduced, so that there is a problem that the magnetic flux amount of the magnet cannot be increased.
[0007]
The present invention has been made to solve the above-described problems, and can increase the thickness of the permanent magnet inserted into the rotor, thereby increasing the amount of magnetic flux and having an electric motor portion with high efficiency. It aims at providing the manufacturing method of a compressor.
[0008]
[Means for Solving the Problems]
The invention according to claim 1
A compressor portion disposed on the opposite side of the bearing portion of the frame having the bearing portion and a motor portion that drives the compressor portion and is disposed on the bearing portion side of the frame are housed in a common casing, and the motor portion Comprises a stator in which a winding is housed in a slot of a laminated magnetic steel sheet and a rotor in which a permanent magnet is inserted into a permanent magnet hole of the laminated magnetic steel sheet, the rotor having an axial direction A fitting portion for inserting a main shaft that drives the compressor portion over a predetermined length and a bearing portion of the frame that is formed adjacent to the fitting portion and that supports the main shaft are accommodated. In the manufacturing method of the electric compressor having a counter bore portion with an expanded inner diameter,
The axial length of the counterbore portion is set to 1/4 to 3/4 of the total axial length of the rotor,
On the counter bore portion side of the rotor, a thin wall portion in which a part of the inner peripheral surface of the counter bore portion is cut out by a predetermined width, and a portion of the inner side in the radial direction of the permanent magnet hole projects toward the permanent magnet side. When the permanent magnet is formed in advance and press-fitted into the permanent magnet hole, the thin portion bulges inward in the radial direction, and the permanent magnet is pressed outward in the radial direction by its elastic force.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, it demonstrates in detail based on suitable embodiment shown on drawing. FIG. 1 is a longitudinal sectional view showing a schematic configuration of an embodiment of an electric compressor related to the present invention. In the figure, the electric compressor 1 includes a casing 2 in which a compressor unit 10 and an electric motor unit 20 are commonly stored. In this case, the frame 3 is disposed above the heel inside the casing 2, the compressor unit 10 is mounted on the upper part of the frame 3, and the electric motor unit 20 is mounted on the lower part of the frame 3.
[0011]
The compressor unit 10 includes a cylinder 11 and a piston 12, one end of a piston rod 13 is coupled to the piston 12, and the other end is coupled to the crankpin 14, and the refrigerant is compressed by the eccentric motion of the crankpin 14. . In addition, since the compression and supply of the refrigerant are well known, the description thereof is omitted.
[0012]
The frame 3 has a bearing portion 4 projecting downward, and a main shaft 24 of the electric motor portion 20 is rotatably fitted to the bearing portion 4, and a crank pin 14 is formed at an upper end thereof. A stator 21 is fixed to the frame 3 around the bearing portion 4 by bolts 22, and a rotor 25 is mounted integrally with the main shaft 24 inside the stator 21. Further, for insulation, a bobbin 23 divided in two in the axial direction is attached to the axial end portion of the stator 21, and the winding 21a is concentratedly wound. Further, lubricating oil is stored at the bottom of the casing 2, and the lubricating oil cools the compressor unit 10 as a whole through the main shaft 24.
[0013]
FIG. 2 is a plan view and a longitudinal sectional view of the rotor 25 constituting the electric motor unit 20 as viewed from the axial direction. The rotor 25 is formed with a permanent magnet hole 28 and a hole to be fastened and fixed by a rivet 31, and two types of holes having different diameters are formed at the center to form a fitting part 26 and a counterbore part 27. These magnetic steel plates are laminated, and these are clamped and fixed in the axial direction by four rivets 31. Permanent magnets 32 are inserted into the permanent magnet holes 28, respectively.
[0014]
Here, the radially inner surface of the permanent magnet 32 forms a part of a cylindrical surface. On the other hand, the inner wall surface on the radially inner side of the permanent magnet hole 28 has a shape projecting flat toward the permanent magnet 32 only in the region indicated by the width W. When the permanent magnet 32 is inserted into the permanent magnet hole 28, the counter bore portion 27 is so formed that the region indicated by the width W bulges radially inward and presses the permanent magnet 32 radially outward by its elasticity. The inner peripheral surface is also cut out by a width W, and a thin portion 29 is formed here.
[0015]
That is, the center of the counterbore portion 27 O, the radius of the counter bore portion 27 when the R _1, width and a center line connecting the circumferential direction of the center of the center O and the permanent magnet holes 28 in the distribution is at W A groove with a dimension Q (> R ₁ ) from the center O and a flat bottom surface is formed on the inner peripheral surface of the counterbore 27, and the inner surface of the permanent magnet hole 28 corresponding to this groove is also formed flat. Has been. The lateral width and thickness of the thin portion 29 are determined so that an appropriate pressing force is applied by press-fitting the permanent magnet 32.
[0016]
Thus, according to the present embodiment, since it is not necessary to provide the slit-shaped opening 36 of the conventional apparatus, the thickness of the permanent magnet 32 can be increased, and the radius of curvature of the radially inner side surface of the permanent magnet 32 can be increased. Since it can be increased, the amount of magnetic flux can be increased as compared with the conventional device.
[0017]
When the total axial length of the rotor 25 shown in FIG. 2 is L ₀ and the axial length of the counterbore 27 is L ₁ , L ₁ is ¼ or more of L ₀ , The permanent magnet 32 can be firmly locked without generating abnormal noise. Incidentally, when the L ₁ longer than 3/4 of the L _0, the insertion resistance of the permanent magnet 32 is increased, at the same time as the workability of the magnet insertion is deteriorated, because it may damage the magnets, the L ₁ of L ₀ It is desirable to set it to 3/4 or less.
[0018]
As described above, the rotor 25 in which the four permanent magnets 32 are fitted in the circumferential direction has been described. However, the present invention is not limited to this, and a larger number of permanent magnets 32 are fitted into the laminated core. It can also be applied to a rotor to be worn.
[0019]
In the above embodiment, the case where the thin portion 29 has a flat plate shape has been described. However, the shape protruding in an arc shape inside the permanent magnet hole 28 when viewed from the center O is the same as described above. Effects can be obtained.
[0020]
【The invention's effect】
As is apparent from the above description, according to the present invention, the thickness of the permanent magnet inserted into the rotor can be increased, thereby increasing the amount of magnetic flux and at the same time having the highly efficient electric motor section. Machine can be provided.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing a schematic configuration of an embodiment of an electric compressor related to the present invention.
2A and 2B are a plan view and a longitudinal sectional view of a rotor constituting the electric motor unit of the embodiment shown in FIG. 1 viewed from the axial direction.
FIG. 3 is a plan view and a longitudinal sectional view of a rotor constituting a motor part of a conventional electric compressor as viewed from the axial direction.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Electric compressor 2 Casing 3 Frame 10 Compressor part 20 Electric motor part 21 Stator 25 Rotor 26 Fitting part 27 Counterbore part 28 Permanent magnet hole 29 Thin part 32 Permanent magnet

Claims (1)

A compressor portion disposed on the opposite side of the bearing portion of the frame having the bearing portion and a motor portion that drives the compressor portion and is disposed on the bearing portion side of the frame are housed in a common casing, and the motor portion Comprises a stator in which a winding is housed in a slot of a laminated magnetic steel sheet and a rotor in which a permanent magnet is inserted into a permanent magnet hole of the laminated magnetic steel sheet, the rotor having an axial direction A fitting portion for inserting a main shaft that drives the compressor portion over a predetermined length and a bearing portion of the frame that is formed adjacent to the fitting portion and that supports the main shaft are accommodated. In the manufacturing method of the electric compressor having a counter bore portion with an expanded inner diameter,
The axial length of the counterbore portion is set to 1/4 to 3/4 of the total axial length of the rotor,
On the counter bore portion side of the rotor, a thin wall portion in which a part of the inner peripheral surface of the counter bore portion is cut out by a predetermined width, and a portion of the inner side in the radial direction of the permanent magnet hole projects toward the permanent magnet side. An electric motor that is formed in advance, and when the permanent magnet is press-fitted into the permanent magnet hole, the thin portion bulges inward in the radial direction, and the permanent magnet is pressed outward in the radial direction by its elastic force. Compressor manufacturing method.

Images