KR102538591B1 - motor driven compressor - Google Patents

Abstract

The present invention is an electric compressor configured to perform mechanical flux weak control, including a motor, an inverter, and a scroll compression unit, a stator coil fixed to an inner circumferential surface of a motor housing of the motor, and a stator coil that rotates and is permanent in an accommodation space of the stator coil. A structure assembly including a rotor having a magnet and a first rotation shaft coupled to a rotation center of the rotor, wherein the structure assembly includes a first spline gear integrally formed at one end of the first rotation shaft wealth; a second spline gear part integrally formed at the other end of the first rotating shaft; a second rotational shaft in the form of a hollow shaft having a first spline gear-fitting portion formed on an inner circumferential surface so as to be slidably coupled to the first spline gear unit and to receive rotational force of the first rotational shaft; an elastic member disposed inside the second rotary shaft and applying a tensile force to an end surface of the first spline gear unit to change the position of the rotor; and a third rotational shaft in the form of a hollow shaft having a second spline gear-fitting portion formed on an inner circumferential surface so as to be slidably coupled to the second spline gear unit to receive the rotational force of the first rotational shaft.

Description

Motor driven compressor {motor driven compressor}

The present invention relates to an electric compressor, and more particularly, to an electric compressor in which a motor and an inverter are integrally provided in a device such as an electric scroll compressor and configured to mechanically control the amount of flux linkage of the motor.

In general, compressors are installed in devices such as vehicles and air conditioners.

Various types of compressors, such as a reciprocating type, a rotating type, and a scroll type, have been developed and used according to their operation method.

Among these compressors, electric compressors use a motor as a power source.

In addition, when the pressure generation method in the electric compressor is a scroll method, it is composed of a motor that receives power and generates rotational force, an inverter for controlling the motor, and a scroll compression unit that generates pressure by transmitting rotational force of the motor.

A conventional scroll-type electric compressor is a scroll compressor as known as Patent Document 1 below, comprising: a drive unit generating rotational force; a drive shaft installed in the housing via a rear bearing and driven by the drive unit; It consists of a scroll wrap to compress the released fluid, is fixed regardless of the rotation of the driving shaft, and has a discharge port for supplying refrigerant to the discharge chamber. It is configured to include a scroll compression unit, an eccentric action unit connected between the orbiting scroll and the driving shaft, and a main frame supporting the orbiting scroll in an axial direction and rotationally supporting the driving shaft.

In particular, since an inverter is provided in a scroll compressor mounted on a vehicle, a method of controlling the capacity of the compressor by performing a variable operation is used.

For example, Patent Document 2 below mentions a method for reducing the decrease in driving efficiency of a motor by minimizing the armature current of the motor as an inverter control device. In an inverter control method that reduces the decrease in driving efficiency of a motor, which is an electric motor, MTPA (Maximum Torque Per Ampere) is performed in the low-speed, high-torque section, and the induced voltage generated by the motor increases in the high-speed operation section. When the voltage exceeds the limit, field weakening control for reducing the amount of flux linkage of the stator coil by the permanent magnet is performed.

In this way, in the prior art, the inverter is provided with a circuit device with a relatively large volume compared to a device that is complex and does not have an inverter control for variable operation by performing maximum torque control or weak flux control per current according to variations in external load conditions. There is something that needs to be done.

Specifically, the inverter of the prior art is disposed inside the inverter housing and includes a printed circuit board (PCB) on which various circuit elements are mounted.

In particular, the circuit elements of the inverter of the printed circuit board of the prior art include a low-power element that consumes little power according to the driving of the inverter and a high-power element that consumes relatively high power compared to the low-power element. Here, the low power device may correspond to an MCU including an IC in which an inverter operation program is stored, and the high power device may correspond to a high voltage regulator, an inductor, an input side capacitor, and the like.

In this way, in the inverter of the conventional electric compressor, a low-power device and a high-power device for variable operation are mounted on one printed circuit board, so the size of the printed circuit board and the device installation space are relatively increased, and heat is generated according to the operation of the high-power device. can cause problems.

In particular, since the prior art inverter applies current to the armature to perform weak flux control and generates armature flux in the opposite direction to the magnetic flux of the permanent magnet to reduce the amount of linkage flux, the total volume of the motor and inverter integrated electric compressor It is very difficult to form a compact structure.

Republic of Korea Patent Publication No. 10-2014-0114737

Therefore, the present invention has been made to solve the problems of the prior art as described above, and an object of the present invention is to provide a mechanical component for mechanically controlling the amount of flux linkage of a motor, so that the motor and the inverter are integrally provided While mechanical flux control is performed inside the motorized compressor, the size of the entire device or the enlargement of the inverter circuit can be prevented, and the heat generation problem caused by the operation of the high power element of the inverter can be minimized. there is

An electric compressor according to an aspect of the present invention for achieving the above object includes a motor, an inverter, and a scroll compression unit, a stator coil fixed to an inner circumferential surface of a motor housing of the motor, and a stator coil in an accommodation space. A structure assembly including a rotor rotating and having a permanent magnet, and a first rotational shaft coupled to a rotation center of the rotor, wherein the structure assembly includes a first unit integrally formed at one end of the first rotational shaft. 1 spline gear part; a second spline gear part integrally formed at the other end of the first rotating shaft; a second rotational shaft in the form of a hollow shaft having a first spline gear-fitting portion formed on an inner circumferential surface so as to be slidably coupled to the first spline gear unit and to receive rotational force of the first rotational shaft; an elastic member disposed inside the second rotary shaft and applying a tensile force to an end surface of the first spline gear unit to change the position of the rotor; and a third rotational shaft in the form of a hollow shaft having a second spline gear-fitting portion formed on an inner circumferential surface so as to be slidably coupled to the second spline gear unit to receive the rotational force of the first rotational shaft.

A stopper portion is formed on an outer circumferential surface of the first rotation shaft, extending along a circumferential direction of the first rotation shaft and protruding in a radial direction of the first rotation shaft.

The stop jaw is formed on an outer circumferential surface of the first rotational shaft based on a position between the second rotational shaft and the rotor, and has a downward stair cross-sectional shape in a direction from the second rotational shaft toward the rotor.

The second rotational shaft may further include a first bearing rotatably supporting an outer circumferential surface of the second rotational shaft based on an inner circumferential surface of a first boss of the motor housing located toward the scroll compression unit.

The third rotational shaft further includes a second bearing rotatably supporting an outer circumferential surface of the third rotational shaft based on an inner circumferential surface of a second boss of a motor housing located on the side of the inverter, the first bearing and the second bearing As a result, the first rotation shaft, the second rotation shaft, and the third rotation shaft are rotated together.

The second rotating shaft may include a hollow shaft portion in which the first spline gear-fitting portion is formed on an inner circumferential surface and the first spline gear portion is inserted; a closing disc unit for closing an end of the hollow shaft unit corresponding to an opposite side of the first spline gear unit of the first rotating shaft; And the pressure in the inner space of the hollow shaft part where the elastic member is disposed and the pressure in the back pressure chamber of the scroll compression part interact with each other between the inner surface of the finishing disc part and the side surface of the first spline gear part. It includes a through hole formed in the finishing disk part and penetrating in the thickness direction of the finishing disk part.

In the electric compressor according to the present invention, which can solve the problem of maintaining an airtight structure due to a change in connector design in the prior art, the rotating shaft of the motor is formed in a double structure for mechanical flux control, and the motor By moving the position of the rotor in the axial direction or restoring it to its original position by elastic force, there is no need to provide circuit means for maximum torque control or weak flux control per electronic current of the existing inverter, so that the motor and It has the advantage of being able to reduce the volume of an electric compressor in which the inverter is integrally configured and to minimize the heat generation problem.

In addition, the electric compressor according to the present invention may not be equipped with an electric element or circuit means for separate electric weak flux control according to the coupling configuration and action of the structure assembly, in this case, the size and weight of the inverter is reduced, and as a result, it can be easily mounted inside a vehicle having a limited space, and the weight of an electric compressor composed of an integrated motor and inverter to be mounted inside the vehicle can also be relatively reduced, and can help vehicle fuel economy. There are advantages to being

In addition, the electric compressor according to the present invention can reduce the current compared to the electric flux weak control method in the high-speed low-torque section according to the application of the mechanical flux weak method, resulting in an advantage of increasing the efficiency of the motor for the electric compressor. there is

1 is a cross-sectional view of an electric compressor according to an embodiment of the present invention.
2 is a cross-sectional view illustrating a mechanical weak flux control structure assembly provided inside the compressor housing shown in FIG. 1;
3 is a cross-sectional view taken along line AA shown in FIG. 2;
4 is a cross-sectional view taken along line BB shown in FIG. 2;
5 is a cross-sectional view for explaining the operating principle of the electric compressor shown in FIG. 1;

Advantages and features of the present invention, and methods of achieving them, will become clear with reference to the detailed description of the following embodiments taken in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various different forms, and only these embodiments make the disclosure of the present invention complete, and common knowledge in the art to which the present invention belongs. It is provided to completely inform the person who has the scope of the invention, and the present invention is only defined by the scope of the claims. Like reference numerals designate like elements throughout the specification.

In describing the embodiments of the present invention, if it is determined that a detailed description of a known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description will be omitted. In addition, terms to be described later are terms defined in consideration of functions in the embodiment of the present invention, which may vary according to the intention or custom of a user or operator. Therefore, the definition should be made based on the contents throughout this specification.

Hereinafter, an electric compressor according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings, and a mechanical flux control structure may be referred to as a structure assembly.

In the drawings, FIG. 1 is a cross-sectional view of an electric compressor according to an embodiment of the present invention, FIG. 2 is a cross-sectional view for explaining a mechanical flux control structure assembly provided inside the compressor housing shown in FIG. 1, and FIG. 2 is a cross-sectional view taken along line A-A, and FIG. 4 is a cross-sectional view taken along line B-B shown in FIG. Also, FIG. 5 is a cross-sectional view for explaining the operating principle of the electric compressor shown in FIG. 1 .

Referring to FIG. 1 , a main body 1, which is an electric compressor according to an embodiment of the present invention, is composed of a motor 100, an inverter 200, a scroll compression unit 300, and a structure assembly 400.

The motor 100 receives power from the inverter 200 and generates power necessary for the operation of the scroll compression unit 300 .

The inverter 200 includes an electrical circuit means for controlling the operation of the scroll compression unit 300 .

The scroll compressing unit 300 plays a role of forming a scroll wrap by turning an orbiting scroll that is shape-wise incorporated into a fixed scroll.

The structure assembly 400 adjusts the position of the rotor 110 in the axial direction of the rotor 110 (eg, a rotor core having a permanent magnet) of the motor 100 instead of the conventional electric weak flux control. , By varying the area W where the stator coil 120 and the permanent magnets of the rotor 110 meet, it plays a role in mechanically adjusting the flux linkage of the permanent magnets of the rotor 110.

Referring to FIG. 1 , the area W where the stator coils 120 and the permanent magnets of the rotor 110 meet is, for example, the area where the inner circumferential surface of the stator coil 120 and the outer circumferential surface of the rotor 110 face each other. As meaning, they may be the same or similar to each other.

That is, referring to FIG. 5 , when the position of the rotor 110 is changed by a mechanical method described later, the area where the inner circumferential surface of the stator coil 120 and the outer circumferential surface of the rotor 110 look at each other after the position change ( N) may be narrowly changed compared to the area (W).

The force required to adjust the position of the rotor 110 is the pressure of the back pressure chamber 310 of the scroll compression unit 300 or the elastic force of the elastic member 450 (eg coil spring) of the structure assembly 400 (eg coil spring). : tensile force). The tensile force of the elastic member 450 may act on the first rotating shaft 410 of the rotor 110 in response to the pressure of the back pressure chamber 310 .

That is, when the pressure in the back pressure chamber 310 is greater than the tensile force of the elastic member 450, the fluid having the pressure in the back pressure chamber 310 passes through the through hole 445 to be described in detail below to form a second rotating shaft. It flows into the inner space of (440). The fluid flowing in and having a pressure greater than the tensile force may push and move the first rotational shaft 410 in a direction away from the scroll compression unit 300 . As a result, the position of the rotor 110 coupled to the first rotation shaft 410 may be changed.

Conversely, when the pressure in the back pressure chamber 310 is smaller than the tensile force of the elastic member 450, the first rotating shaft 410 can be pulled by the tensile force of the elastic member 450. The fluid introduced into the inner space of the second rotational shaft 440 escapes back to the back pressure chamber 310 through the through hole 445 . As a result, the first rotation shaft 410 and the rotor 110 may move in a direction closer to the scroll compression unit 300 . Also, the rotor 110 may return to its original position.

The structural assembly 400 includes a stator coil 120 fixed to the inner circumferential surface of the motor housing 101 of the motor 100, and a rotor 110 rotating in the accommodation space of the stator coil 120 and having permanent magnets. and a first rotation shaft 410 shaft-coupled to the center of rotation of the rotor 110.

Referring to Figures 2 to 4, the structure assembly 400 is a first spline gear portion 420 integrally formed at one end of the first rotational shaft 410, and integrally formed at the other end of the first rotational shaft 410 It includes a second spline gear portion 430 formed of.

Here, the first rotation shaft 410, the first spline gear unit 420, and the second spline gear unit 430 have the same axial direction.

One end and the other end of the first rotating shaft 410 for the contraction action base material may be respectively a first spline gear part 420 and a second spline gear part 430 by machining.

The structure assembly 400 is slidably coupled to the first spline gear unit 420 (eg, slidably coupled) to receive the rotational force of the first rotational shaft 410, the first spline gear fitting portion on the inner circumferential surface. 441 includes a second rotational shaft 440 in the form of a hollow shaft formed thereon. A lubricant or a fluid for lubrication may be further interposed between the first spline gear unit 420 and the second rotational shaft 440 .

The second rotary shaft 440 includes a hollow shaft part 443, a finishing disc part 444, and a through hole 445.

The hollow shaft part 443 forms a first spline gear fitting part 441 on its inner circumferential surface, has an inner space for mounting the elastic member 450, and the first spline gear part ( 420) is inserted.

The finishing disk part 444 serves to close the open end of the hollow shaft part 443 by welding or screwing. That is, the finishing disk part 444 closes or closes the end of the hollow shaft part 443 corresponding to the opposite side of the first spline gear part 420 of the first rotating shaft 410.

The through hole 445 is formed between the inner surface of the finishing disk part 444 and the end side of the first spline gear part 420 of the hollow shaft part 443 where the elastic member 450 is disposed. It serves to share the pressure so that the pressure in the inner space and the pressure in the back pressure chamber 310 of the scroll compression unit 300 can interact.

To this end, a through hole 445 is formed in the finishing disk part 444 and passes through the finishing disk part 444 in the thickness direction.

The formation position of the through hole 445 in the finishing disk part 444 is determined based on a place that does not overlap with the elastic member 450, or is spaced apart from the center of the finishing disk part 444 or is located eccentrically. it can be done Therefore, the flow of fluid through the through hole 445 can be made freely or at least blocked by the elastic member 450 so as not to be interfered with.

In addition, the structure assembly 400 is an elastic member disposed inside the second rotation shaft 440 and applying a tensile force to the end surface of the first spline gear unit 420 in order to change the position of the rotor 110. Includes (450).

One end of the elastic member 450 may be connected to the inner surface of the finishing disk unit 444, and the other end of the elastic member 450 may be connected to the side of the end of the first spline gear unit 420. .

The elastic member 450 may be formed in the form of a coil spring, but in the case of a means capable of applying a tensile force by being connected to the first spline gear unit 420 (eg, welding or bolt fixing), it may not necessarily be a coil spring, , It may be composed of equivalents such as conventional elastic means equivalent thereto.

In addition, the structure assembly 400 includes a third rotational shaft 460 slidably coupled to the second spline gear unit 430 located on the opposite side of the second rotational shaft 440 .

The third rotational shaft 460 is manufactured in the form of a hollow shaft in which a second spline gear-fitting part 461 is formed on the inner circumferential surface of the third rotational shaft 460 so as to receive the rotational force of the first rotational shaft 410 .

A lubricant or a fluid for lubrication may be further interposed between the second spline gear unit 430 and the third rotation shaft 460 .

As shown in FIG. 2 , a stop jaw portion 470 is formed on the outer circumferential surface of the first rotating shaft 410 .

The stop jaw part 470 stops the first rotational shaft 410 or the rotor 110 from excessively moving in the direction of the second rotational shaft 440, so that the elastic member located inside the second rotational shaft 440 ( 450) may play a role in preventing excessive compression or damage.

As shown in FIG. 5, the stop jaw 470 is in sliding contact with the inner circumferential surface of the guide ring 102 installed inside the motor housing 101, and as a result, the movement of the rotor 110 is caused by the rotor 110. to be induced in the axial direction (CL) of

Referring to FIG. 2 , the stop jaw portion 470 extends along the circumferential direction of the first rotating shaft 410 and protrudes in the radial direction of the first rotating shaft 410 .

At this time, the stop jaw part 470 is formed on the outer circumferential surface of the first rotational shaft 410 based on the position between the second rotational shaft 440 and the rotor 110, and the second rotational shaft 440 It has a downward stair cross-sectional shape in the direction toward the rotor 110.

Referring to FIG. 5 , the second rotating shaft 440 rotates the outer circumferential surface of the second rotating shaft 440 based on the inner circumferential surface of the first boss 103 of the motor housing 101 located on the side of the scroll compression unit 300. It further includes a possibly supporting first bearing 442 .

The third rotational shaft 460 is a second bearing for rotatably supporting the outer circumferential surface of the third rotational shaft 460 based on the inner circumferential surface of the second boss 104 of the motor housing 101 located on the side of the inverter 200 ( 462) is further included.

By the first bearing 442 and the second bearing 462, the first rotation shaft 410, the second rotation shaft 440, and the third rotation shaft 460 can be rotated together.

At this time, the rotor 110 has a second rotation shaft 440, a first bearing 442, a third rotation shaft 460, and a second bearing 462 through the first rotation shaft 410 by the stator coil 120. ) to transmit rotational force. In addition, since the first rotating shaft 410 of the rotor 110 has a spline-shaped double structure and is movably coupled to the second rotating shaft 440 and the third rotating shaft 460, respectively, a circuit to be described below. Position control of the former 110 becomes possible.

That is, the key to the present invention is to adjust the flux linkage of the permanent magnets in the rotor 110 by adjusting the position of the rotor 110 .

As shown in FIG. 5 , according to the present invention, when the back pressure in the back pressure chamber 310 is high, high torque is required for the motor 100, and conversely, when the back pressure in the back pressure chamber 310 is low, low torque is required for the motor 100. It is required.

The through hole 445 allows the pressure between the inner space of the second rotating shaft 440 where the elastic member 450 is located and the inner space of the back pressure chamber 310 to be unique.

When the back pressure in the back pressure chamber 310 increases, the pressure of the fluid flowing from the back pressure chamber 310 through the through hole 445 into the inner space of the second rotary shaft 440 is reduced by the first rotary shaft 410 and the rotor ( 110) can be pushed and moved, and the amount of flux linkage between the permanent magnet of the rotor 110 and the stator coil 120 can be increased.

As is known in the field of motor technology, the amount of flux linkage is proportional to the back EMF. Therefore, when the amount of flux-linkage increases, the counter electromotive force increases, and the power density can be improved by the increase in the counter electromotive force. That is, a highly efficient feature capable of improving the power density of a motor mechanically rather than using an electronic control method that changes the voltage or current of a conventional motor may be included in the present invention.

Conversely, when the back pressure in the back pressure chamber 310 is lowered, the fluid in the inner space of the second rotational shaft 440 escapes toward the back pressure chamber 310 through the through hole 445 again, so that the tensile force of the elastic member 450 The rotor 110 and the first rotational shaft 410 are moved toward the scroll compression unit 300, that is, closer to the finishing disc unit 444 by (e.g., spring tension), and as a result, the flux linkage can be reduced. there will be

The rotor 110 may receive force in a rotational direction or transmit rotational force to its double structure.

On the other hand, although the electric compressor according to the present invention has been described according to embodiments, the scope of the present invention is not limited to specific embodiments, and various Alternatives, modifications and variations may be implemented.

Therefore, the embodiments described in the present invention and the accompanying drawings are not intended to limit the technical idea of the present invention, but to explain, and the scope of the technical idea of the present invention is not limited by these embodiments and the accompanying drawings. . The protection scope of the present invention should be construed according to the claims, and all technical ideas within the equivalent range should be construed as being included in the scope of the present invention.

1: body 100: motor
110: rotor 120: stator coil
200: inverter 300: scroll compression unit
400: structure assembly 410: first rotational shaft
420: first spline gear part 430: second spline gear part
440: 2nd rotating shaft 444: finishing disk unit
445: through hole 450: elastic member
460: third rotational shaft 470: stop jaw

Claims (6)

In the electric compressor including a motor, an inverter and a scroll compression unit,
A structure assembly comprising a stator coil fixed to an inner circumferential surface of a motor housing of the motor, a rotor rotating in an accommodation space of the stator coil and having a permanent magnet, and a first rotation shaft coupled to a rotation center of the rotor. including,
The structural assembly,
a first spline gear unit integrally formed at one end of the first rotating shaft;
a second spline gear unit integrally formed at the other end of the first rotation shaft;
a second rotational shaft in the form of a hollow shaft having a first spline gear-fitting portion formed on an inner circumferential surface so as to be slidably coupled to the first spline gear unit and to receive rotational force of the first rotational shaft;
an elastic member disposed inside the second rotary shaft and applying a tensile force to an end surface of the first spline gear unit to change the position of the rotor; and
A third rotational shaft in the form of a hollow shaft having a second spline gear-fitting portion formed on an inner circumferential surface so as to be slidably coupled to the second spline gear unit to receive the rotational force of the first rotational shaft;
motorized compressor.
According to claim 1,
On the outer circumferential surface of the first rotating shaft,
A stop jaw portion extending along the circumferential direction of the first rotational shaft and protruding in the radial direction of the first rotational shaft is formed.
motorized compressor.
According to claim 2,
The stop jaw,
Formed on an outer circumferential surface of the first rotational shaft based on a position between the second rotational shaft and the rotor, and having a downward stair cross-sectional shape in a direction from the second rotational shaft toward the rotor
motorized compressor.
According to claim 1,
The second axis of rotation,
Further comprising a first bearing rotatably supporting an outer circumferential surface of the second rotation shaft based on an inner circumferential surface of a first boss of the motor housing located toward the scroll compression unit.
motorized compressor.
According to claim 4,
The third axis of rotation,
Further comprising a second bearing rotatably supporting an outer circumferential surface of the third rotating shaft based on an inner circumferential surface of a second boss of a motor housing located on the side of the inverter,
The first rotational shaft, the second rotational shaft, and the third rotational shaft are rotated together by the first bearing and the second bearing.
motorized compressor.
According to claim 1,
The second axis of rotation,
a hollow shaft portion formed on an inner circumferential surface of the first spline gear-fitting portion and into which the first spline gear portion is inserted;
a closing disc unit for closing an end of the hollow shaft unit corresponding to an opposite side of the first spline gear unit of the first rotating shaft; and
The pressure of the inner space of the hollow shaft part in which the elastic member is disposed and the pressure of the space of the back pressure chamber of the scroll compression part interact with each other between the inner surface of the finishing disk part and the side surface of the first spline gear part. A through hole formed in the disk portion and penetrating in the thickness direction of the finishing disk portion; including
motorized compressor.

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