ELECTRIC COMPRESSOR

Description

CROSS REFERENCE TO RELATED PATENT APPLICATION

The present application claims priority to Korea Patent Application No.10-2024-0137938, filed Oct. 10, 2024, the entire contents of which is incorporated herein for all purposes by this reference.

FIELD

The present disclosure relates to an electric compressor, more particularly, to an electric compressor configured to compress a refrigerant with a driving force of a motor.

BACKGROUND

Generally, a compressor is an apparatus compressing a fluid such as a refrigerant gas and the like, and is applied to an air conditioning (A/C) system of a building, a vehicle, and the like.

The compressor is classified into a reciprocating compressor that compresses a refrigerant according to which pistons reciprocate, and a rotary compressor that compresses a refrigerant while rotating. The reciprocating compressor includes a crank compressor that transmits a driving force from a drive source to a plurality of pistons using a crank, a swash plate compressor that transmits a driving force from a drive source to a shaft installed with a swash plate, and the like, according to the power transmission from the drive source. The rotary compressor includes a vane rotary compressor that utilizes a rotating rotary shaft and vane, and a scroll compressor that utilizes an orbiting scroll and a fixed scroll.

In addition, depending on a driving method, the compressors may be classified into a mechanical compressor that uses an engine and an electric compressor that uses a motor (hereinafter, an electric compressor).

FIG. 1 is a cross-sectional view of a conventional electric compressor, and FIG. 2 is an enlarged cross-sectional view of A part in FIG. 1.

Referring to FIGS. 1 and 2, the conventional electric compressor includes a housing 10, a compression mechanism 20 configured to compress a refrigerant in the housing 10, a motor 30 configured to generate power needed in driving the compression mechanism 20, a drive shaft 40 rotated by the motor 30 and configured to deliver power to the compression mechanism 20, and a bearing 50 supported by the housing and supporting the drive shaft 40.

However, in the conventional electric compressor, there was a problem in that noise increases as the drive shaft 40 is vibrated in an axial direction while the vehicle is traveling.

SUMMARY

Therefore, the present disclosure aims to provide an electric compressor capable of suppressing axial vibration of the drive shaft, thereby suppressing increase of the noise.

One embodiment is an electric compressor, including: a housing; a compression mechanism configured to compress a refrigerant in the housing; a motor configured to generate power; a drive shaft configured to be rotated by the motor and deliver power to the compression mechanism; a bearing supported by the housing and supporting the drive shaft; and a damping mechanism configured to suppress axial vibration of the drive shaft, and the damping mechanism may include an elastic member, a support member supporting the elastic member, and a retainer supporting the support member.

One surface of the elastic member may be in contact with the drive shaft, and another surface of the elastic member may be in contact with the support member.

The drive shaft may include: a first portion extending to be coupled to the motor; a third portion supported by the bearing; and a second portion extending from the first portion to the third portion, and an outer diameter of the second portion may be formed smaller than an outer diameter of the first portion and an outer diameter of the third portion, and a first stepped surface may be formed between the first portion and the second portion, and a second stepped surface may be formed between the third portion and the second portion, and the retainer may be supported by the second stepped surface, the support member may be supported by the retainer on an opposite side of the second stepped surface based on the retainer, and the elastic member may support the first stepped surface while being supported by the support member on an opposite side of the retainer based on the support member.

An axial height of the elastic member before the elastic member, the support member, and the retainer are assembled into the drive shaft may be formed greater than an axial distance from the support member to the first stepped surface when the elastic member, the support member, and the retainer are assembled into the drive shaft.

The elastic member may be formed in an annular shape extending along a circumferential direction of the drive shaft, and one end of the elastic member may be supported on the first stepped surface over a whole circumference of 360 degrees, and another end of the elastic member may be supported on the support member over a whole circumference of 360 degrees.

Each of the first stepped surface and the support member may be formed in an annular shape along the circumferential direction of the drive shaft.

An outer diameter of the one end of the elastic member may be formed smaller than or equal to an outer diameter of the first stepped surface, an inner diameter of the one end of the elastic member may be formed greater than the outer diameter of the third portion, an outer diameter of the another end of the elastic member may be formed greater than the outer diameter of the one end of the elastic member, and an inner diameter of the another end of the elastic member may be formed smaller than the inner diameter of the one end of the elastic member.

An outer diameter of the support member may be formed greater than or equal to the outer diameter of the another end of the elastic member, and an inner diameter of the support member may be formed smaller than the inner diameter of the another end of the elastic member and greater than the outer diameter of the third portion.

The outer diameter of the first stepped surface and the outer diameter of the first portion may be formed smaller than the outer diameter of the support member.

An outer diameter of the retainer may be formed greater than the inner diameter of the support member and smaller than the outer diameter of the support member.

The retainer may be formed in a snap ring shape extending from one end to another end along the circumferential direction of the drive shaft, and an inner diameter of the retainer may be formed smaller than an outer diameter of the second stepped surface and greater than or equal to the outer diameter of the second portion.

The elastic member, the support member, and the retainer may be assembled into the drive shaft such that the third portion sequentially passes through an inner circumferential portion of the elastic member and an inner circumferential portion of the support member, passes through an inner circumferential portion of the retainer which is circumferentially spaced as an external force is applied to the retainer, and is seated on the second portion as the external force applied to the retainer is removed and the retainer is retracted.

The bearing may include an outer wheel supported on the housing, an inner wheel accommodated in an inner circumferential portion of the outer wheel and supporting an outer circumferential surface of the third portion, and a ball interposed between the outer wheel and the inner wheel, and the outer diameter of the retainer may be formed smaller than or equal to an outer diameter of the inner wheel.

The housing may include a shaft receiving groove configured to accommodate the bearing, an outer diameter of the outer wheel may be formed greater than or equal to an inner diameter of the shaft receiving groove, and an inner diameter of the inner wheel may be formed greater than the outer diameter of the third portion.

When the drive shaft is axially moved, the retainer may be supported on the inner wheel, the inner wheel may be supported on the ball, the ball is supported on the outer wheel, and the outer wheel may be supported on the shaft receiving groove.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of a conventional electric compressor.

FIG. 2 is an enlarged cross-sectional view of A part in FIG. 1.

FIG. 3 is a cross-sectional view of an electric compressor according to an embodiment of the present disclosure.

FIG. 4 is an enlarged cross-sectional view of B part in FIG. 3.

FIG. 5 is an exploded perspective view illustrating a drive shaft, an elastic member, a support member, and a retainer in FIG. 4.

FIG. 6 is a cross-sectional view of a damping mechanism of an electric compressor according to another embodiment of the present disclosure.

DETAILED DESCRIPTION

Hereinafter, an electric compressor according to the present disclosure will be described in detail with reference to the accompanying drawings.

FIG. 3 is a cross-sectional view of an electric compressor according to an embodiment of the present disclosure, FIG. 4 is an enlarged cross-sectional view of B part in FIG. 3, and FIG. 5 is an exploded perspective view illustrating a drive shaft, an elastic member, a support member, and a retainer in FIG. 4.

Referring to FIGS. 3 to 5, the electric compressor according to an embodiment of the present disclosure may include: a housing 100; a compression mechanism 200 configured to compress a refrigerant in the housing 100; a motor 300 configured to generate power needed for the compression mechanism 200; a drive shaft 400 configured to be rotated by the motor 300 and deliver power to the compression mechanism 200; and a bearing 500 supported by the housing 100 and supporting the drive shaft 400.

The housing 100 may include a center housing 110, a front housing 120 coupled to the center housing 110 and forming a motor accommodating space in which the motor 300 is accommodated, and a rear housing 130 coupled to the center housing 110 on an opposite side of the front housing 120 with respect to the center housing 110 and forming a compression mechanism accommodating space in which the compression mechanism 200 is accommodated.

Here, the center housing 110 includes a center housing partition wall 112 configured to partition the motor accommodating space and the compression mechanism accommodating space and a center housing annular wall 114 extending along an outer circumferential portion of the center housing partition wall 112, and a shaft receiving groove 112a into which the drive shaft 400 is inserted may be formed in the center housing partition wall 112.

In addition, the front housing 120 includes a front housing partition wall 122 facing the center housing partition wall 112, and a front housing annular wall 124 extending along an outer circumferential portion of the front housing partition wall 122 and fastened to the center housing annular wall 114, and a shaft receiving groove 122a into which the drive shaft 400 is inserted may be formed in the front housing partition wall 122.

The compression mechanism 200 may include a fixed scroll 210 fixedly installed in the housing 100, and an orbiting scroll 220 engaged with the fixed scroll 210 to form a compression chamber together with the fixed scroll 210 and configured to be orbited by the drive shaft 400.

Here, in the present embodiment, the compression mechanism 200 is formed as a so-called scroll type, but is not limited thereto, and may be configured as other types such as a reciprocating type and a vane rotary type.

The motor 300 may include a stator 310 supported by the front housing annular wall 124, and a rotor 320 positioned inside the stator 310 and configured to be rotated by an interaction with the stator 310.

The drive shaft 400 is formed to be press-inserted into the rotor 320 to penetrate the rotor 320, and may include a first end 410 extending from the rotor 320 to an opposite side of the compression mechanism and inserted into the drive shaft receiving groove 122a and a second end 420 extending from the rotor 320 to a side of the compression mechanism 200 and inserted into the drive shaft receiving groove 112a.

The bearing 500 may include an outer wheel 510 supported on an inner circumferential surface of the drive shaft receiving groove 122a, an inner wheel 520 accommodated in the inner circumferential portion of the outer wheel 510 and supporting the first end 410, and a ball 530 interposed between the outer wheel 510 and the inner wheel 520.

Here, as the outer wheel 510 includes an outer track 512 into which one side of the ball 530 is inserted, the inner wheel 520 includes an inner track 522 into which another side of the ball 530 is inserted, the outer track 512 includes an outer track one side surface 512a disposed on a side of the compression mechanism 200 based on a center of the ball 530, and an outer track another side surface 512b disposed on an opposite side of the outer track one side surface 512a based on the center of the ball 530, and the inner track 522 includes an inner track one side surface 522a disposed on a side of the compression mechanism 200 based on the center of the ball 530, and an inner track another side surface 522b disposed on another side of the inner track one side surface 522a based on the center of the ball 530, the ball 530 may be supported not only in a circumferential direction of the drive shaft 400, but also in an axial direction thereof by the outer wheel 510 and the inner wheel 520.

Meanwhile, when the outer wheel 510 is formed to be press-inserted into the drive shaft receiving groove 122a, and the inner wheel 520 is formed to be press-inserted into the first end 410, there may be a difficulty in assembling the housing 100, the bearing 500, and the drive shaft 400 into one another.

In consideration of the above, in the present embodiment, an outer diameter of the outer wheel 510 is formed greater than or equal to an inner diameter of the shaft receiving groove 122a so that the outer wheel 510 can be press-inserted into the shaft receiving groove 122a, while an inner diameter of the inner wheel 520 is formed to be greater than an outer diameter of the first end 410 (more accurately, a third portion 416 which will be described below) so that the inner wheel 520 cannot be press-inserted into the shaft receiving groove 122a.

However, as a result, the drive shaft 400 may be axially vibrated with respect to the bearing 500.

In consideration of the above, in the present embodiment, a damping mechanism 600 configured to suppress axial vibration of the drive shaft 400 may be further included, and the damping mechanism 600 may include an elastic member 610 compressed and restored when the drive shaft 400 is axially vibrated and configured to dampen the axial vibration of the drive shaft 400.

Here, the damping mechanism 600 may further include a support member 620 supporting the elastic member 610 and a retainer 630 configured to suppress the elastic member 610 and the support member 620 from leaving the drive shaft 400, and the support member 620 and the retainer 630 may be formed such that the support member 620 is supported on the retainer 630 and the elastic member 610 is supported on the support member 620 to support the drive shaft 400 so that the elastic member 610 does not generate an uneven force.

In more detail, the first end 410 may include a first portion 412 extending to be coupled to the rotor 320, a second portion 414 extending from the first portion 412 to an opposite side of the rotor 320, and a third portion 416 extending from the second portion 414 to an opposite side of the first portion 412; forming a tip end of the first end 410; and having an outer circumferential surface being supported on an inner circumferential surface of the inner wheel 520.

In addition, an outer diameter of the second portion 414 is formed smaller than an outer diameter of the first portion 412 and an outer diameter of the third portion 416, thereby an annular first stepped surface 413 extending continuously along the circumferential direction of the drive shaft 400 may be formed between the first portion 412 and the second portion 414, and an annular second stepped surface 415 extending continuously along the circumferential direction of the drive shaft 400 may be formed between the third portion 416 and the second portion 414.

The elastic member 610 may be formed in an annular shape extending continuously along the circumferential direction of the drive shaft 400.

In addition, an inner diameter of the elastic member 610 may be formed greater than the outer diameter of the third portion 416 so that the third portion 416 can pass through an inner circumferential portion of the elastic member 610 so as to allow the elastic member 610 to be assembled with the drive shaft 400.

In addition, the inner diameter of the elastic member 610 may be formed smaller than an outer diameter of the first stepped surface 413 so that the elastic member 610 can be supported on the first stepped surface 413.

The elastic member 610 may be formed in an annular shape extending continuously along the circumferential direction of the drive shaft 400.

In addition, an inner diameter of the support member 620 may be formed greater than the outer diameter of the third portion 416 so that the third portion 416 can pass through an inner circumferential portion of the support member 620 so as to allow the support member 620 to be assembled with the drive shaft 400.

In addition, the inner diameter of the support member 620 may be formed smaller than an outer diameter of the elastic member 610, and an outer diameter of the support member 620 may be formed greater than the inner diameter of the elastic member 610 so that the elastic member 610 can be supported on the support member 620.

Here, the elastic member 610 may be formed in a conical shape so as to provide efficient damping. That is, the elastic member 610 may include one end 612 supported on the first stepped surface 413 and another end 614 supported on the support member 620, and an outer diameter of the one end 612 of the elastic member 610 may be formed smaller than or equal to the outer diameter of the first stepped surface 413, and an outer diameter of the another end 614 of the elastic member 610 may be formed greater than the outer diameter of the one end 612 of the elastic member 610. In addition, an inner diameter of the one end 612 of the elastic member 610 may be formed greater than the outer diameter of the third portion 416 as described above, and an inner diameter of the another end 614 of the elastic member 610 may be formed greater than the outer diameter of the third portion 416 and greater than the inner diameter of the one end 612 of the elastic member 610.

At this instance, the support member 620 may be formed to support the another end 614 of the conical elastic member 610. That is, the outer diameter of the support member 620 may be formed greater than or equal to the outer diameter of the another end 614 of the elastic member 610, and the inner diameter of the support member 620 may be formed smaller than or equal to the inner diameter of the another end 614 of the elastic member 610.

Here, as the outer diameter of the one end 612 of the elastic member 610 is formed smaller than the outer diameter of the another end 614 of the elastic member 610, the outer diameter of the first stepped surface 413 and the outer diameter of the first portion 412 may be formed smaller than the outer diameter of the support member 620. With this configuration, compared to a case where the outer diameter of the first stepped surface 413 and the outer diameter of the first portion 412 are formed greater than the outer diameter of the support member 620, it is advantageous in the viewpoint of the noise because the inertia moment of a rotation body including the drive shaft 400, the elastic member 610, the support member 620 and the retainer 630 is reduced.

The retainer 630 may be formed such that the retainer 630 can be supported on the second stepped surface 415 on an opposite side of the elastic member 610 based on the support member 620 and can support the support member 620. That is, an inner diameter of the retainer 630 may be formed smaller than an outer diameter of the second stepped surface 415 and greater than or equal to the outer diameter of the second portion 414, and an outer diameter of the retainer 630 may be formed greater than the inner diameter of the support member 620.

Here, in general, the retainer 630 is supported on the inner wheel 520 as will be described below, and when the drive shaft 400 is moved too much toward the motor, the retainer 630 may be supported on the second stepped surface 415.

In addition, it is preferable that the outer diameter of the retainer 630 is formed smaller than the outer diameter of the support member 620 so that the inertia moment of the rotation body can be reduced.

In addition, it is preferable that the outer diameter of the retainer 630 is formed smaller than or equal to the outer diameter of the inner wheel 520 so that the retainer 530 can be axially supported on the inner wheel 520 while in contact with the inner wheel 520, but the retainer 530 cannot be in contact with the outer wheel 510 and the ball 530.

In addition, the retainer 630 can be formed in a snap ring shape extending from the one end 612 to the another end 614 along the circumferential direction of the drive shaft 400 so that the retainer 630 having the inner diameter smaller than the outer diameter of the second stepped surface 415 can be assembled into the drive shaft 400.

In addition, the damping mechanism 600 may be assembled into the drive shaft 400 such that the third portion 416 which sequentially passes through the inner circumferential portion of the elastic member 610 and the inner circumferential portion of the support member 620 passes through an inner circumferential portion of the retainer 630 which is circumferentially spaced as an external force is applied to the retainer 630, and the external force applied to the retainer 630 is removed and the retainer 630 is retracted in a state in which the elastic member 610, the support member 620 and the retainer 630 are seated on an outer circumferential portion of the second portion 414.

Here, an axial height of the elastic member 610 before the damping mechanism 600 is assembled into the drive shaft 400 may be formed greater than an axial distance from the support member 620 to the first stepped surface 413 after the damping mechanism 600 is assembled into the drive shaft 400 so that a preload can be applied to the damping mechanism 600, that is, the retainer 630 can come into close contact with the inner wheel 520, and the elastic member 610 can come into close contact with the first stepped surface 413 and the support member 620.

Hereinafter, the functions and effects of the present electric compressor will be described.

That is, when power is applied to the motor 300, as the rotor 320 and the drive shaft 400 are rotated, power is delivered to the compression mechanism 200, and a low-temperature low-pressure refrigerant is introduced into the motor accommodating space, the refrigerant in the motor accommodating space is introduced into the compression mechanism 200 to be compressed to get into a high-temperature and high-pressure state, and is discharged to the outside of the housing 100.

In the above course, the drive shaft 400 is supported by the bearing 500, however, there is limitation for the bearing 500 to suppress the axial vibration of the drive shaft 400.

However, in the present embodiment, the axial vibration of the drive shaft 400 can be suppressed by the damping mechanism 600 as the present embodiment includes the damping mechanism 600 which includes the elastic member 610 configured to be compressed and then restored at the axial vibration of the drive shaft 400.

In addition, as the damping mechanism 600 further includes the support member 620, the elastic member 610 can be supported stably and damage to the elastic member 610 can be prevented.

In addition, as the damping mechanism 600 further includes the retainer 630, the elastic member 610 and the support member 620 can be prevented from leaving the drive shaft 400.

Here, when the drive shaft 400 is axially moved, the axial vibration of the drive shaft 400 can be suppressed, as the elastic member 610 axially supports the first stepped surface 413, the support member 620 axially supports the elastic member 610, the retainer 630 axially supports the support member 620, the inner wheel 520 axially supports the retainer 630, the ball 530 axially supports the inner wheel 520 by supporting the inner track one side surface 522a and the inner track another side surface 522b, the outer wheel 510 axially supports the ball 530 through the outer track one side surface 512a and the outer track another side surface 512b, and the shaft receiving groove 122a axially supports the outer wheel 510.

Meanwhile, the drive shaft 400 and the damping mechanism 600 are formed such that the elastic member 610 supports the drive shaft 400 while the elastic member 610 is supported on the support member 620, thereby the vibration and the noise of the drive shaft 400 can be further reduced.

In more detail, as the retainer 630 is supported on the second stepped surface 415, the support member 620 is supported on the retainer 630 on an opposite side of the second stepped surface 415 based on the retainer 630, and the elastic member 610 supports the first stepped surface 413 while being supported on the support member 620 on an opposite side of the retainer 630 based on the support member 620, thereby the one end 612 of the elastic member 610 is evenly supported over a whole circumference of 360 degrees by the annular first stepped surface 413, the another end 614 of the elastic member 610 is evenly supported over a whole circumference of 360 degrees by the annular support member 620, displacement at one random circumferential position of the elastic member 610 is the same as displacement at another circumferential position of the elastic member 610, and therefore, a force generated at the one random circumferential position of the elastic member 610 can become equal to a force generated at another circumferential position of the elastic member 610. That is, the elastic member 610 may generate a uniform force. As a result, a force which tilts the drive shaft 400 is not generated and the vibration and the noise of the drive shaft 400 can be effectively reduced.

However, the present technology is not limited thereto.

FIG. 6 is a cross-sectional view of a damping mechanism of an electric compressor according to another embodiment of the present disclosure.

Referring to FIG. 6, a damping mechanism of an electric compressor according to another embodiment of the present disclosure may have positions of the elastic member 610 and the support member 620 changed to each other. That is, the retainer 630 is supported on the second stepped surface 415, the support member 620 is supported on the first stepped surface 413, and the one end 612 of the elastic member 610 is supported on the retainer 630 as the elastic member 610 is interposed between the retainer 630 and the support member 620, the another end 614 of the elastic member 610 may support the support member 620. In this case as well, the elastic member 610 may suppress the axial vibration of the drive shaft 400.

However, as the one end 612 of the elastic member 610 is supported on the retainer 630 in a snap ring shape, the one end 612 of the elastic member 610 may not be evenly supported in the circumferential direction. That is, a portion of the one end 612 of the elastic member 610 may not be supported by a cut portion of the retainer 630. In addition, there may be a deformation which occurs during traveling in that the one end 612 of the elastic member 610 may be axially spaced apart with respect to the another end 614 of the elastic member 610, and in such a case, the displacement at the one random circumferential position of the elastic member 610 and the displacement at the another circumferential position of the elastic member 610 are different from each other, and a force generated at the one random circumferential position of the elastic member 610 and a force generated at the another circumferential position of the elastic member 610 may become different from each other. That is, the elastic member 610 may not generate a uniform force. As a result, a force which tilts the drive shaft 400 is generated and the vibration and the noise of the drive shaft 400 may rather increase.

Therefore, the embodiment disclosed in FIG. 6 may be preferable than the embodiments disclosed in FIGS. 3 to 5.