JPWO2016199884A1 - Electric compressor - Google Patents

Abstract

Even if the strength of the housing is partially increased from the structure of the housing while the contact ratio in the circumferential direction between the stator core and the housing is close to that in the case where the stator core and the housing are in contact with each other, the stator core An electric compressor capable of suppressing partial deformation is provided. In an electric compressor (1) in which an electric motor (4) and a compression mechanism (3) are accommodated in a housing (2) and a stator core (17) of a stator (15) constituting the electric motor (4) is fixed to the housing (2) by an interference fit, the housing (2) has an attachment foot portion. 21 and 22 have strength increasing portions 27 and 28 whose strength is increased compared to other portions, and in a portion where pressing force acts on the stator core 17 side from the strength increasing portions 27 and 28 side in an interference fit state, the stator core 17 Concave portions 23 and 24 are formed as non-contact portions with the outer peripheral surface of the. [Selection] Figure 1

Description

  The present invention relates to an electric compressor provided with a compression mechanism and an electric motor for driving the compression mechanism in a housing, and more particularly, to an apparatus for fixing a stator core constituting the electric motor to the housing by an interference fit.

  An electric compressor is configured by housing a compression mechanism and an electric motor that drives the compression mechanism in a housing. As a method of fixing a stator core constituting the electric motor to the housing, for example, an interference fit is used. .

  As an example of this interference fit, as shown in Patent Document 1, for example, the inner diameter of the housing is formed slightly smaller than the outer diameter of the stator core, and the housing is thermally expanded by bringing it to a high temperature state. There is a shrink fit that fits a stator core at room temperature into the housing, and then shrinks the housing by returning the housing to room temperature to fix the stator core to the housing. As another example of an interference fit, the outer diameter of the stator core is formed slightly larger than the inner diameter of the housing, the stator core is set to a low temperature state to reduce the outer diameter of the stator core, and the low temperature state stator core is inserted into the normal temperature housing. Then, there is also a cold fitting in which the stator core is fixed to the housing by returning the stator core to the original state by returning the stator core to room temperature.

  And in patent document 2, in order to prevent troubles, such as a crack of a stator core or a housing, and a housing and a stator core tightening more than necessary at the time of either of the above-mentioned interference fittings, it is a gap part. A configuration is shown in which a plurality of portions are provided on the inner peripheral surface of the housing or the outer peripheral surface of the stator core along the circumferential direction of the peripheral surface, and a portion where the housing and the stator core come into contact is partially shown.

  On the other hand, when the electric compressor is used for vehicle air conditioning, in order to mount the electric compressor on the vehicle, the housing is attached to a predetermined portion of the vehicle, for example, as shown in FIG. A mounting foot portion is provided on the outer surface.

JP-A-9-287585 Japanese Patent Laid-Open No. 2004-1129888 JP 2008-133729 A

  However, as shown in Patent Document 2, a plurality of gaps are provided on the inner peripheral surface of the housing or the outer peripheral surface of the stator core along the circumferential direction of the peripheral surface, and a portion where the housing and the stator core are in contact with each other is partially provided. Then, in the interference fit state, the pressing force acting on the stator core by the housing causes a variation in the circumferential direction, the stator core is partially deformed, and the dimension of the gap space between the stator core and the rotor is not uniform in the circumferential direction. The inconvenience that the vibration and noise of the motor of the electric compressor increase and the performance of the electric compressor decreases.

  On the other hand, it can be considered that the plurality of gaps in Patent Document 2 are completely abolished so that the inner peripheral surface of the housing and the outer peripheral surface of the stator core are in contact with each other over the entire periphery. However, when the housing is provided with a mounting foot as disclosed in Patent Document 3, the strength of the portion of the housing having the mounting foot is partially increased as compared to other portions of the housing. It becomes. Thus, the partial increase in strength of the housing due to the structure of the housing can also be caused by factors other than the mounting feet, such as the thickness of a part of the housing being thicker than the other part.

  When the housing and the stator core are fixed by shrinkage fitting, when the housing shrinks at room temperature, the pressing force acting on the stator core by the housing is higher than the other portions at the portion where the strength of the housing is partially increased. Become stronger. For this reason, in the stator core, the deformation amount of the portion that contacts the portion where the strength of the housing is partially increased is larger than that of other portions, and a portion that is partially distorted inward is generated in the stator core. Accordingly, as in the case of Patent Document 2, since the dimension of the gap space between the stator core and the rotor is not uniform in the circumferential direction, vibration and noise due to the electric motor of the electric compressor increase, and the performance of the electric compressor is reduced. The inconvenience of lowering occurs.

  Therefore, in the present invention, when fixing the stator of the electric motor to the housing by an interference fit, the contact ratio in the circumferential direction between the stator core and the housing is close to that in the case where the stator core and the housing are in contact with the entire circumference. An object of the present invention is to provide an electric compressor capable of suppressing partial deformation of a stator core even when the strength is partially increased from the structure of the housing.

  An electric compressor according to the present invention includes a compression mechanism, an electric motor that drives the compression mechanism, and a housing that houses the compression mechanism and the electric motor. The electric motor includes a stator having a stator core, and a drive shaft. A rotor that is fixed and rotatably disposed inside the stator, and the inner peripheral surface of the housing and the outer peripheral surface of the stator core are brought into contact with each other by an interference fit, and the stator is fixed in the housing. In the electric compressor, the housing partly has a strength increasing portion whose strength is increased compared to other portions, and the portion where the pressing force acts on the stator core from the strength increasing portion side in the interference fit state. A non-contact portion is formed in which the inner peripheral surface of the housing and the outer peripheral surface of the stator core are not in contact with each other (Claim 1).

  As a result, the contact ratio in the circumferential direction between the stator core and the housing is similar to that in the case where the stator core and the housing are in contact with each other around the entire circumference. By forming a non-contact portion that does not contact the outer peripheral surface of the stator core, it is possible to prevent a pressing force stronger than other portions based on the strength increasing portion from acting on the outer peripheral surface of the stator core from the inner peripheral surface of the housing. The

  In the electric compressor according to the invention of claim 2, the strength increasing portion is formed by a mounting foot portion provided on an outer surface of the housing in order to attach the electric compressor to an attached body, and the non-contact portion is The concave portion is formed on a portion of the inner peripheral surface of the housing between the mounting leg portion and the outer peripheral surface of the stator core. The mounted body is, for example, an automobile or other vehicles.

  As a result, the housing has a mounting foot, and even if a partial strength increase portion occurs in the housing due to the mounting foot, the contact ratio in the circumferential direction between the stator core and the housing is in contact with the entire circumference of the stator core and the housing. Forming a recess in the inner peripheral surface of the housing between the mounting foot and the outer peripheral surface of the stator core while making it closer to the case, it is stronger than other parts based on the strength increasing part The pressing force is prevented from acting on the outer peripheral surface of the stator core from the inner peripheral surface of the housing.

  The electric compressor according to a third aspect of the invention is characterized in that a rib is provided on the outer surface of the housing so as to extend from the mounting foot in substantially the same direction as the axial direction of the drive shaft.

  As a result, even if a recess is formed in the inner peripheral surface of the housing as a non-contact portion at a portion between the mounting foot portion on the inner peripheral surface of the housing and the outer peripheral surface of the stator core, the rib extends from the mounting foot portion to the housing. By providing the strength of the housing is maintained.

  As described above, according to the present invention, while the contact ratio in the circumferential direction between the stator core and the housing is close to the case where the stator core and the housing are in contact with each other on the entire circumference, there is a partial strength increasing portion in the housing. Even if there is a non-contact portion between the inner peripheral surface of the housing and the outer peripheral surface of the stator core, a stronger pressing force than the other portion based on the strength increasing portion is applied from the inner peripheral surface of the housing to the outer periphery of the stator core. It is possible to suppress working on the surface. Therefore, when the stator core is fixed to the housing by the interference fit, deformation of the stator core can be avoided even if the housing has a partial strength increasing portion.

  In particular, according to the second aspect of the present invention, even if the housing has a mounting foot portion, and the mounting foot portion causes a partial strength increasing portion in the housing, the contact ratio in the circumferential direction between the stator core and the housing is determined as the stator core. And forming the concave portion in the inner peripheral surface of the housing between the mounting foot and the outer peripheral surface of the stator core while making the shape close to the case of contact with the entire circumference of the housing, thereby increasing the strength portion. It is possible to suppress a pressing force stronger than other parts based on the above from the inner peripheral surface of the housing to the outer peripheral surface of the stator core. Therefore, when the stator core is fixed to the housing by the interference fit, the deformation of the stator core can be suppressed even if the housing has a mounting foot portion as a partial strength increasing portion.

  In particular, according to the invention of claim 3, even if a recess is formed on the inner peripheral surface of the housing as a non-contact portion in a portion between the mounting foot portion of the inner peripheral surface of the housing and the outer peripheral surface of the stator core, By providing the housing with ribs extending from the mounting feet, the strength of the housing can be maintained.

FIG. 1 is a cross-sectional view showing a configuration example of the electric compressor of the present invention and an aspect having both a non-contact portion and a rib. 2 is a cross-sectional view of the electric compressor of FIG. 1 cut along line AA. FIG. 3 is a cross-sectional view of the electric compressor showing Reference Example 1 having a configuration in which a portion where the housing and the stator are in contact is partially formed. FIG. 4 is a cross-sectional view of an electric compressor showing Reference Example 2 in which a portion where the housing and the stator are in contact with each other extends over the entire circumference. FIG. 5 is a graph showing that the present invention is superior in suppressing the deformation amount of the stator core as compared with Reference Example 1 and Reference Example 2.

  Embodiments of an electric compressor according to the present invention will be described below with reference to the accompanying drawings.

 In FIG.1 and FIG.2, the electric compressor 1 suitable for the refrigerating cycle which uses a refrigerant | coolant as a working fluid is shown. This electric compressor 1 is provided with a compression mechanism 3 on the right side in FIG. 1 and a motor 4 for driving the compression mechanism 3 on the left side in FIG. Yes. The left side in FIG. 1 is the front side of the electric compressor 1, and the right side in FIG. 1 is the rear side of the electric compressor 1.

  In this embodiment, the housing 2 is assembled to an electric motor housing member 2a that houses an electric motor 4 that drives the compression mechanism 3, and one end side (front end side) in the axial direction of the electric motor housing member 2a. An inverter housing member 2b for housing a substrate (not shown) on which a drive circuit in which a control circuit for controlling driving and an inverter are integrated is mounted, and the other end side (rear end) in the axial direction of the motor housing member 2a. And a compression mechanism accommodating housing member 2c that accommodates the compression mechanism 3. The motor housing housing member 2 a and the inverter housing housing member 2 b are connected by a fastening bolt 5, and the motor housing housing member 2 a and the compression mechanism housing housing member 2 c are connected by a fastening bolt 6.

  A partition wall 8 in which a shaft support portion 8a is integrally formed is provided on the side of the inverter housing member 2b that faces the motor housing housing member 2a. Moreover, the partition wall 9 in which the shaft support part 9a was integrally formed is provided in the side which opposes the compression mechanism accommodation housing member 2c of the electric motor accommodation housing member 2a. The drive shaft 10 is rotatably supported by the shaft support portions 8 a and 9 a of the partition walls 8 and 9 via bearings 11 and 12. Furthermore, the interior of the housing 2 accommodates the compression mechanism 3 in order from the rear side to the front side of the electric compressor 1 by the partition walls 9 and 8 formed on the electric motor accommodation housing member 2a and the inverter accommodation housing member 2b. And a motor housing space 13a for housing the motor 4, and an inverter housing space 13b for housing the inverter circuit board. In this embodiment, the inverter accommodating space 13b is formed by closing the open end of the inverter accommodating housing member 2b with the lid 14.

  As the compression mechanism 3, for example, a known scroll type having a fixed scroll member and a turning scroll member disposed to face the fixed scroll member is used. An example of the fixed scroll member and the orbiting scroll member of the compression mechanism 3 will be described. The fixed scroll member is provided on the entire circumference along the outer edge of the disk-shaped end plate fixed to the housing and the end plate. A cylindrical outer peripheral wall erected toward the front side of the compressor, and a spiral spiral wall extending from the end plate toward the front side of the compressor inside the outer peripheral wall; . The orbiting scroll member has a disc-shaped end plate and a spiral-shaped spiral wall standing from the end plate toward the rear side of the compressor, and a boss portion formed on the back surface of the end plate. The eccentric shaft provided at the rear end portion of the drive shaft 10 is connected, and is supported so as to be capable of swiveling around the shaft center of the drive shaft 10. The fixed scroll member and the orbiting scroll member are engaged with each other by the respective spiral walls so that the compression chamber is surrounded by a space surrounded by the end plate and the spiral of the fixed scroll member and the end plate and the spiral wall of the orbiting scroll member. Is forming.

  A refrigerant inlet is formed between the outer peripheral wall of the fixed scroll member and the spiral wall of the orbiting scroll member to suck in a refrigerant introduced from a suction port 20 (to be described later) through the motor housing space 13a. Further, a discharge port for discharging the refrigerant gas compressed by the compression mechanism 3 is formed in the approximate center of the end plate of the fixed scroll member of the compression mechanism 3.

  As a result, when the rotor 16 described later rotates and the drive shaft 10 rotates, the orbiting scroll member orbits around the axis of the drive shaft 10 and the compression chamber moves from the outer peripheral side to the center side of the spiral walls of both scroll members. The refrigerant gas is compressed by moving while the volume is gradually reduced, and the compressed refrigerant gas is discharged from the discharge port formed in the end plate of the fixed scroll member.

  A stator 15 and a rotor 16 constituting the electric motor 4 are accommodated in an electric motor accommodation space 13 a formed in a portion of the housing 2 in front of the partition wall 9. The stator 15 is formed of an iron-based material and has a cylindrical stator core 17, a coil 18 (shown by a broken line in FIG. 2) wound around the teeth of the stator core 17, and an axial end ( An insulator bobbin (hereinafter abbreviated as “bobbin”) 19 attached to the coil end is configured, and is fixed to the inner peripheral surface of the housing 2 (electric motor housing member 2a). The drive shaft 10 is fixedly mounted with a rotor 16 in which a magnet is accommodated inside the stator 15. The rotor 16 is rotated by the rotating magnetic force formed by the stator 15 to rotate the drive shaft 10.

  Further, in this embodiment, a suction port 20 for sucking refrigerant gas is formed on the outer peripheral wall of the housing 2 (motor housing member 2a) facing the motor housing space 13a, and the refrigerant (to be compressed) is formed through the suction port 20. Fluid) is introduced into the motor housing space 13a and guided to the compression mechanism 3 through the motor housing space 13a.

  Furthermore, in this embodiment, the electric compressor 1 is mounted on the same side as the suction port 20 of the housing 2 so that the electric compressor 1 can be mounted on a vehicle when configuring a refrigeration cycle of a vehicle air conditioner such as an automobile. A foot 21 is provided and a mounting foot 22 is provided on the opposite side of the housing 2 from the mounting foot 21 side. These mounting feet 21 and 22 are formed integrally with the housing 2 and have bolt insertion holes 21a and 22a for mounting and fixing to a vehicle via bolts (not shown).

  By the way, as shown in FIGS. 1 and 2, the electric compressor 1 of the present invention has a non-contact portion between the housing 2 and the stator core 17 at a portion between the mounting foot 21 of the housing 2 and the stator core 17. In order to form, a recess 23 is formed. In this embodiment, the recess 23 is curved in an arc shape toward the outer peripheral surface side of the housing 2. As shown in FIGS. 1 and 2, the electric compressor 1 also has a non-contact portion between the housing 2 and the stator core 17 in a portion between the mounting foot portion 22 of the housing 2 and the stator core 17. In order to form, a recess 24 is formed. In this embodiment, the recess 24 has an arcuate shape toward the outer peripheral surface of the housing 2.

  As shown in FIG. 1, these recesses 23, 24 are forces that press from the housing 2 to the stator core 17 when the housing 2 and the stator core 17 are shrink-fitted in a range along the axial direction of the housing 2. It may be formed so as to cover substantially the entire range of the range to which is added. On the other hand, as shown in FIG. 2, the recesses 23 and 24 may not be arranged at positions symmetrical with respect to the drive shaft 10, or the radial widths of the mounting feet 21 and 22. However, it may be provided in a range that is a part of the above. Furthermore, the shape of the recesses 23 and 24 is not particularly limited as long as it is possible to ensure non-contact between the housing 2 and the stator core 17, and is not particularly limited.

  Further, as shown in FIG. 1, the electric compressor 1 according to the present invention is provided with ribs 25 and 26 extending in the axial direction from the mounting feet 21 and 22 toward the compression mechanism 3 on the side peripheral surface of the housing 2. ing. The ribs 25 and 26 are formed integrally with the housing 2.

  For comparison with the above-described electric compressor 1 of the present invention, FIG. 3 shows the electric compressor 100 of Reference Example 1, and FIG. 4 shows the electric compressor 200 of Reference Example 2. These electric compressors 100 and 200 are similar to the electric compressor 1 of the present invention in their basic structures, and are respectively a compression mechanism (not shown), and electric motors 101 and 201 that drive the compression mechanism, Housings 102 and 202 for accommodating the compression mechanism and the electric motors 101 and 201 are provided. The electric motors 101 and 201 have stators 103 and 203 and rotors 104 and 204, respectively. The stators 103 and 203 include stator cores 105 and 205 whose side surfaces are cylindrical, and the rotors 104 and 204 have a drive shaft 106. , 206, and is disposed so as to be rotatable integrally with the drive shafts 106, 206 inside the stators 103, 203.

  Furthermore, the electric compressors 100 and 200 have attachment feet 107 and 108 or attachment feet 207 and 208 in order to fix and mount the electric compressors 100 and 200 on the vehicle.

  In both the electric compressor 1 of the present invention and the electric compressors 100 and 200 as reference examples, the stator cores 17, 105, 205 and the housings 2, 102, 202 are fixed by, for example, shrink fitting of shrink fitting. Yes. That is, the inner diameters of the housings 2, 102, 202 are formed slightly smaller than the outer diameters of the stator cores 17, 105, 205, and the housings 2, 102, 202 are thermally expanded by bringing them to a high temperature state. The stator cores 17, 105, and 205 at room temperature are fitted into the chambers 2, 102, and 202, and then the housings 2, 102, and 202 are contracted by returning the housings 2, 102, and 202 to room temperature, and the stator cores 17, 105, and 205 are contracted. Is fixed to the housing 2, 102, 202.

  In addition, as shown in FIG. 3, the electric compressor 100 of Reference Example 1 has six recesses 109 formed in the circumferential direction of the inner peripheral surface of the housing 102 on the stator core 105 side of the housing 102. Two stator holding portions 110 are arranged at substantially equal intervals along the circumferential direction of the inner peripheral surface of the housing 102. That is, the electric compressor 100 of Reference Example 1 is configured such that the inner peripheral surface of the housing 102 and the outer peripheral surface of the stator core 105 are in partial contact.

  For this reason, in the electric compressor 100 of Reference Example 1, the pressing force acting on the stator core 105 by the housing 102 during the shrink-fitting is concentrated on the six stator holding portions 110, so the pressing force acting on the stator core 105 The stator core 105 is deformed into a substantially polygonal shape (for example, a substantially hexagonal shape). Therefore, as shown in FIG. 5, according to the measurement results under a predetermined condition, the degree of deformation of the stator core 105 after shrink fitting with respect to the perfect circle is 1.3 points. It is beyond the allowable range.

  As shown in FIG. 4, the electric compressor 200 of Reference Example 2 does not have a concave portion corresponding to the concave portion 107 of the electric compressor 100 of Reference Example 1 on the inner peripheral surface of the housing 202. The surface is in contact with the outer peripheral surface of the stator core 205 over the entire periphery. For this reason, it is avoided that the deformation amount of the stator core 205 increases due to the partial contact range between the housing 202 and the stator core 205 as in the electric compressor 100 of Reference Example 1.

  However, as shown in FIG. 4, the electric compressor 200 has mounting feet 207 and 208, and the portion of the housing 202 having the mounting feet 207 and 208 is thicker than the other portions of the housing 202. Since the thickness is increased, the structure has strength increasing portions 209 and 210. For this reason, in the strength increasing portions 209 and 210 of the housing 202, the pressing force acting on the stator core 205 becomes stronger than the other portions of the housing 202. For this reason, in the stator core 205, the amount of deformation of the portion that contacts the strength-increasing portions 209 and 210 of the housing is larger than other portions, and a portion that is partially distorted inward is generated in the stator core 205. Therefore, as shown in FIG. 5, according to the measurement result under a predetermined condition, the degree of deformation of the stator core 205 after shrink fitting with respect to the perfect circle is 0.8 point, and the deformation that can be allowed as the stator core. The amount is not up.

  On the other hand, in the present invention 1, as shown in FIG. 2, the housing 2 has strength increasing portions 27 and 28 by the mounting feet 21 and 22, and the mounting feet 21 and 22 of the housing 2, the stator core 17, and the like. On the other hand, the recesses 23 and 24 are provided as non-contact portions with the stator core 17 between them. Unlike FIG. 1, the mounting feet 21 and 22 are not formed with the ribs 25 and 26. Yes. According to such a configuration of the first aspect of the present invention, it is possible to suppress a pressing force stronger than other portions based on the strength increasing portions 27 and 28 from acting on the outer peripheral surface of the stator core 17 from the inner peripheral surface of the housing 2. Therefore, as shown in FIG. 5, according to the measurement result under a predetermined condition, the degree of deformation of the stator core 17 with respect to the perfect circle after shrink fitting is 0.2 points. This is a significant decrease from 2.

  And in this invention 2, as FIG.1 and FIG.2 shows, the housing 2 has the intensity | strength increase parts 27 and 28 by the attachment leg parts 21 and 22 like this invention 1, and the attachment leg part of the housing 2 is shown. Concave portions 23 and 24 are provided as non-contact portions between the stator cores 17 and 22 and the stator core 17, and ribs 25 and 26 are formed on the mounting feet 21 and 22. According to the configuration of the present invention 2 as described above, the strength of the housing 2 is supplemented by the ribs 25 and 26 even if the recesses 23 and 24 are provided in the housing 2. Moreover, as shown in FIG. 5, even in the electric compressor 1 according to the second aspect of the present invention, the degree of deformation of the stator core 17 after shrink fitting with respect to the perfect circle is 0.3 points. Although the numerical value is slightly worse than that of the present invention 1, the numerical value can be kept significantly reduced as compared with the reference example 1 and the reference example 2.

  However, according to the present invention 1 and the present invention 2, when the stator core 17 is fixed to the housing 2 by an interference fit, the contact ratio in the circumferential direction between the stator core 17 and the housing 2 is changed over the entire circumference of the stator core 17 and the housing 2. Even if there are strength increasing portions 27 and 28 in the housing 2, the partial deformation of the stator core 17 can be suppressed while being close to the case of contact.

DESCRIPTION OF SYMBOLS 1 Electric compressor 2 Housing 3 Compression mechanism 4 Electric motor 10 Drive shaft 15 Stator 16 Rotor 17 Stator core 21 Mounting foot 22 Mounting foot 23 Recess 24 Recess 25 Rib 26 Rib 27 Strength increase part 28 Strength increase part

Claims (3)

A compression mechanism, an electric motor that drives the compression mechanism, and a housing that accommodates the compression mechanism and the electric motor, the electric motor being fixed to a drive shaft and rotating inside the stator An electric compressor comprising: a rotor arranged in a possible manner; wherein the inner peripheral surface of the housing and the outer peripheral surface of the stator core are brought into contact with each other by an interference fit, and the stator is fixed in the housing;
The housing partly has a strength increasing portion whose strength is increased compared to other portions, and the inner periphery of the housing is located at a portion where a pressing force acts on the stator core from the strength increasing portion side in the interference fit state. A non-contact portion is formed in which a surface and the outer peripheral surface of the stator core are not in contact with each other.   The strength increasing portion is formed by a mounting foot provided on an outer surface of the housing for mounting the electric compressor to a mounted body, and the non-contact portion is an inner peripheral surface of the housing, The electric compressor according to claim 1, wherein the electric compressor is a recess formed in a portion between the mounting foot and the outer peripheral surface of the stator core.   3. The electric compressor according to claim 2, wherein a rib is provided on the outer surface of the housing so as to extend from the mounting foot in substantially the same direction as the axial direction of the drive shaft.

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