KR20040073268A - Electric compressor - Google Patents

Abstract

PURPOSE: An electromotive compressor is provided to maintain stable efficiency by preventing sliding loss due to bad junction between a bearing part and a shaft. CONSTITUTION: An electromotive compressor has an electromotive mechanism(103) and a compression mechanism(102) driven by the electromotive mechanism. The electromotive mechanism is formed of a stator(113) having a winding coil(113d) and a rotator(114) having a rotator iron core(115) and a permanent magnet(115a). A shaft(104) has an eccentric shaft part(117), a main shaft part(116), and a sub-bearing(121), wherein the main shaft part and the sub-bearing are coaxially arranged. A cylinder block(105) has a compression chamber(110). A main bearing(120) is installed in the cylinder block, orthogonal to an axial core of the compression chamber for axially supporting the main shaft part. A piston(109) reciprocates in the compression chamber. A connecting element(108) connects the piston with the eccentric shaft part. A hermetic container(101) contains the electromotive mechanism and the compression mechanism with storing lubricating oil(112).

Description

Electric Compressor {ELECTRIC COMPRESSOR}

The present invention relates to a motor-driven compressor used in refrigeration refrigeration equipment, air conditioning equipment and the like.

BACKGROUND ART In recent years, for a motor-driven compressor used in a refrigeration apparatus such as a home refrigerator refrigerator, for the purpose of reducing power consumption, high efficiency has been progressed by lowering lubricating oil, driving an inverter, and employing a synchronous motor. In addition, in order to increase the volumetric efficiency of the refrigeration refrigerator, a more compact compressor is required.

BACKGROUND ART Conventional electric compressors have improved stators and main bearings in order to improve efficiency, and are disclosed in, for example, Japanese Unexamined Patent Application Publication No. 2001-73948.

5 is a longitudinal sectional view of such a conventional electric compressor. In Fig. 5, the sealed container 1 of the electric compressor stores the lubricating oil 12 at the bottom, and the motor unit 3 composed of the stator 13 and the rotor 14 and the compression driven by the same. The mechanism part 2 is accommodated.

Next, the detailed description of the compression mechanism part 2 is shown below. In the cylinder block 5 which forms the substantially cylindrical cylinder 7 which comprises the compression mechanism part 2, the aluminum system which is a non-magnetic material which supports the shaft 4 and is formed substantially perpendicular to the cylinder 7, The bearing part 6 which consists of materials is provided. The shaft 4 having the eccentric portion 4a is inserted into the bearing portion 6 and mounted thereon, and the rotor 14 is fixed.

The piston 9 which slides in the cylinder 7 forms the compression chamber 10, and is connected via the connecting rod 8 which is a connection means with the eccentric part 4a. The oil supply pipe 11 is provided in the front-end | tip of the eccentric part 4a.

Next, the detailed description of the electric motor part 3 is shown below. The electric motor part 3 consists of the stator 13 which wound the coil in the stator iron core which consists of laminated electrical steel sheets, and the rotor 14 which built the permanent magnet 15b in the rotor iron core 15 which consists of laminated electrical steel sheets. It is a two-pole induction motor. Moreover, the hollow bore part 16 is provided in the edge part of the rotor iron core 15 which opposes the compression mechanism part 2, The bearing part 6 inside the hollow bore part 16 is provided. Is extended.

The operation of the conventional reciprocating motor-type compressor configured as described above will be described next. With the rotation of the rotor 14 of the electric motor part 3, the shaft 4 rotates, and the rotational movement of the eccentric portion 4a of the shaft 4 is transmitted through the connecting rod 8 to the piston 9. By being conveyed to the piston 9, the piston 9 reciprocates in the compression chamber 10. As a result, the refrigerant gas from the cooling system (not shown) is sucked into the compression chamber 10, and is then continuously discharged to a cooling system such as a refrigeration refrigerator or an air conditioner.

In addition, with the rotation of the shaft 4, the oil supply pipe 11 attached to the lower end of the shaft 4 rotates, the lubricating oil 12 is pumped upward by the pump action by the centrifugal force, and the compression mechanism part Lubrication is carried out by the sliding parts of the bearing part 6, the cylinder 7, the connecting rod 8, the piston 9, etc. of (2).

However, in the above conventional configuration, if there is a bias in the spatial distance between the rotor 14 and the stator 13, a force that pulls the rotor 14 toward the smaller spatial distance, that is, a magnetic attraction force is generated. In particular, when the permanent magnet 15b incorporated in the rotor iron core 15 is a permanent magnet having strong magnetic force such as rare earth, this magnetic attraction force acts as a larger force when the deviation of the space distance is large.

As a result, the shaft 4 fixed to the rotor 14 and inserted into and mounted in the bearing portion 6 is inclined in the bearing portion 6, and is joined between the bearing portion 6 and the shaft 4. Defect occurs. When the shaft 4 rotates and slides in the bearing part 6 in such a bad state of joining, abrasion may arise in the sliding surfaces of both the bearing part 6 and the shaft 4.

Further, in another conventional example described in the above-described prior art, a structure in which the main bearing end face of the iron-based material and the end face of the compression mechanism part side of the rotor iron core do not overlap is disclosed. In this case, if the required bearing length of the bearing portion 6 of the cantilever bearing type is maintained, the entire length of the shaft 4 becomes long, and accordingly, the center of the rotor 14 and the bearing portion 6 Since the distance is also long, there is a drawback that wear may occur on the sliding surfaces of both the bearing portion 6 and the shaft 4. This is because the magnetic attraction force generated between the rotor 14 and the stator 13 acts as a strong moment in the bearing portion 6, and thus the force of the poor bonding generated between the bearing portion 6 and the shaft 4. Because this becomes bigger.

The present invention solves such a conventional problem, and an object thereof is to provide an electric compressor having high efficiency and high reliability.

The electric compressor of this invention has the following structures.

As an electric compressor,

(a) a motor part comprising a stator having a winding and a rotor having a rotor iron core and a permanent magnet;

(b) a compression mechanism part driven by the electric motor part;

The compression mechanism unit,

(b-1) a shaft having an eccentric shaft portion, a main shaft portion and a sub bearing,

The main shaft portion and the sub bearing are disposed on the same axis up and down with the eccentric shaft portion therebetween,

(b-2) a cylinder block having a compression chamber,

(b-3) a main bearing installed in the cylinder block so as to be orthogonal to the axis of the compression chamber, and for supporting the main shaft portion;

(b-4) a sub-bearing provided on the cylinder block to support the minor shaft portion;

(b-5) a piston reciprocating in the compression chamber,

(b-6) comprising connecting means for connecting the piston and the eccentric shaft portion,

(c) a sealed container for storing lubricating oil and accommodating the electric motor part and the compression mechanism part.

1 is a longitudinal sectional view of an electric compressor according to a first embodiment of the present invention;

2 is a longitudinal sectional view of an electric compressor according to a second embodiment of the present invention;

3 is a longitudinal sectional view of an electric compressor according to a third embodiment of the present invention;

4 is a longitudinal sectional view of an electric compressor according to a fourth embodiment of the present invention;

5 is a longitudinal sectional view of a conventional electric compressor.

Explanation of symbols for the main parts of the drawings

101: closed container 102, 302: compression mechanism part

103, 203, 303, 403: motor portion 104: shaft

105, 305: Cylinder block 106, 306: Bore part

107: cylinder 108: connecting rod

109: piston 111: oil supply mechanism

110: compression chamber 113, 213: stator

114, 214, 314, 414: rotor 116: spindle part

117: eccentric shaft portion 118: minor shaft portion

120, 130: main bearing 121: sub bearing

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described, referring drawings.

(First embodiment)

1 is a longitudinal sectional view of a motor-driven compressor according to a first embodiment of the present invention.

In FIG. 1, the sealed container 101 accommodates the compression mechanism part 102 and the electric motor part 103 which drives this compression mechanism part.

The refrigerant enclosed in the airtight container 101 is R134a having an ozone depletion coefficient of zero, a hydrocarbon refrigerant having a low warming coefficient represented by R 600a, or the like. In the sealed container 101, lubricating oil 112 having a viscosity of 5 to 10 [cts] compatible with the refrigerant is stored.

Next, the detailed description of the compression mechanism part 102 is shown below. The shaft 104 has an eccentricity, a shaft portion 117, a major shaft portion 116, and a minor shaft portion 118. The main shaft part 116 and the sub-shaft part 118 are arrange | positioned up and down coaxially with the eccentric shaft part 117 interposed. The oil supply mechanism 111 formed in the shaft 104 communicates with one end in the lubricating oil 112, and the other end communicates with the upper end of the shaft 104.

The cylinder block 105 is made of cast iron, and the main bearing 120 for axially supporting the substantially cylindrical compression chamber 110 and the main shaft portion 116 is integrally formed, and the shaft portion 118 is axially supported. The sub bearing 121 is fixed. The piston 109 is slidably inserted into the compression chamber 110, and the piston 109 and the eccentric shaft portion 117 are connected by a connecting rod 108 as a connecting means.

Next, the detailed description of the electric motor part 103 is shown below. The motor unit 103 is composed of a stator 113 and a rotor 114 and is driven at any of a plurality of operating frequencies of 30 [HZ], 50 [HZ], 70 [HZ], and 80 [HZ]. It is a driven motor. The stator 113 has a plurality of teeth 113b formed radially on the iron core 113a and wound the winding 113d directly on the teeth 113b via the insulating member 113c. Forming a concentrated winding motor. The rotor 114 is fixed to the main shaft portion 116 of the shaft 104 and has a permanent magnet 115a embedded in the rotor iron core 115.

The permanent magnet 115a is made of, for example, neodymium, iron, or boron-based ferromagnetic material of the rare earth magnet. And assuming that the plane including the compression mechanism side end portion 115b of the rotor iron core 115, and a plane substantially perpendicular to the axis of the main shaft portion 116, the main bearing 120 does not intersect this plane. It is composed.

The operation of the motor-driven compressor configured as described above will be described below.

When energization is performed to the stator 113, the rotor 114 rotates the shaft 104, and the eccentric motion of the eccentric shaft portion 117 is transmitted to the piston 109 through the connecting rod 108 so that the piston 109 can be rotated. Reciprocates in the compression chamber 110. As a result, the refrigerant gas is sucked and compressed from the cooling system (not shown) into the compression chamber 110, and then discharged again to the cooling system.

In addition, the lubricating oil 112 is pumped up by the oil supply mechanism 111 formed in the shaft 104, and is discharged from the upper end of the shaft 104.

Here, since the permanent magnet 115a embedded in the rotating magnetic core 115 is made of a material having strong magnetic force such as rare earth, extremely strong magnetic attraction force is applied to a portion where the distance between the rotor 114 and the stator 113 is small. Occurs.

However, when the shaft 104 receives the unbalanced load due to the magnetic attraction force generated between the rotor 114 and the stator 113, the conventional cantilever bearing is used to form the center axis of the shaft 104 of the inner wall of the main bearing. On the contrary, the upper and lower ends in the diagonal direction were subjected to unbalanced loads, but the structure of both of the support bearings was opposite to the sub bearing side end of the main bearing inner wall and the inner side of the sub bearing inner wall diagonally with respect to the central axis of the shaft 104. The opposite main bearing side end is subjected to the uneven load, and the distance between the points is about twice as long.

The extension of the distance between the points is that the inclination angle of the shaft 104 becomes smaller inside the bearing portion, and as a result, the joining failure between the bearing portion and the shaft 104 becomes less likely to occur, resulting in sliding due to the joining failure. Loss can be avoided and stable efficiency can be maintained. At the same time, the sliding noise caused by poor bonding can be suppressed, and an electric compressor with low noise can be realized. In addition, since the load to the shaft 104 during the compressor operation is held on both sides of the eccentric shaft 117 (point) under which the compressive load from the piston 109 is applied, it is almost equal to this point. Load distribution becomes possible, and the reliability of the sliding part of the shaft 104 can be improved compared with the cantilever type which load concentrates only on one bearing part.

In addition, since the load of the shaft 104 that is applied during the operation of the compressor is less inclined and is loaded in a large area, the surface pressure of the main bearing 120 and the sub bearing 121 decreases and the main bearing 120 is lower than that of the cantilever bearing. ) Can be shortened, and the overall height of the compressor can be reduced. In addition, with the reduction of the sliding length, the viscous resistance to the sliding portion can be reduced, resulting in high efficiency.

In addition, since the main bearing 120 is formed integrally with the cylinder block 105, the main bearing 120 is made of cast iron, which is an iron-based material, but is provided so that the rotor iron core 115 and the main bearing 120 do not contact each other. The magnetic lines of force of the permanent magnets 115a embedded in the rotor core 115 hardly interfere with the main bearing 120. Therefore, eddy current loss hardly occurs in the main bearing portion, and high efficiency is obtained.

In addition, the motor unit 103 is driven by an inverter, and when the high-speed operation of 70 to 80 kW is performed depending on the load, the magnetic attraction force is increased, and the force to tilt the shaft 104 is increased. In that case, since the shaft 104 is comprised by the both-side support bearing structure which axially supports by the bearing of both the main bearing 120 and the sub bearing 121, the inclination of this shaft 104 can be prevented and it slides simultaneously. The loss can be reduced. Therefore, while maintaining high efficiency, the joining failure by the inclination of a shaft can be prevented and reliability improves.

In addition, when the motor unit 103 executes the low-rotation operation of 30 kV by the drive of the inverter, it is because of the configuration of the two-side supporting bearings which shaft-shapes the shaft 104 by both bearings of the main bearing 120 and the sub bearing 121. Inclination can be prevented and sliding loss can be reduced. Therefore, even in the low viscosity lubricating oil which made the viscosity of the lubricating oil 112 5-10 [cts], sufficient reliability can be acquired.

In addition, the stator 113 has a plurality of radially formed teeth 113b on the iron core 113a, and wound the winding 113d directly on the teeth 113b via an insulating member 113c. As a result, there is no coil end required in the case of distributed winding. Therefore, the total height of the stator 113 and the rotor 114 can be made low, and it is possible to suppress the height of the electric compressor lower. Since the overall heights of the stator 113 and the rotor 114 are low, it is easy to attain uniformity between the stator 113 and the rotor 114, and as a result, magnetic attraction force is less likely to occur, resulting in inclination. It is possible to avoid an increase in input current or an increase in noise.

In addition, in this embodiment, although the connecting rod 108 was used as a connecting means for connecting a piston and an eccentric shaft, instead of this, connection means, such as a ball joint and a scotch yoke, can also be applied.

(Second embodiment)

2 is a longitudinal sectional view of a motor-driven compressor according to a second embodiment of the present invention. In addition, about the structure similar to 1st Example, the same code | symbol is attached | subjected and detailed description is abbreviate | omitted.

In FIG. 2, the motor part 203 is a stator 213 formed by winding a winding around a stator iron core made of a laminated electrical steel sheet, and a rotor formed by installing secondary conductors on the rotor iron core 215 made of a laminated electrical steel sheet. It is a two-pole synchronous motor composed of 214. The rotor iron core 215 contains a permanent magnet 215a made of, for example, neodymium, iron, and boron-based ferromagnetic materials of rare earth magnets. The rest of the configuration is the same as that of the first embodiment.

The operation of the electric compressor configured as described above will be described next. The motor unit 203 starts as an induction motor at start-up, executes synchronous drawing in near the synchronous rotational speed, and performs synchronous operation.

Here, since the permanent magnet 215a embedded in the rotor iron core 215 is made of a material having strong magnetic force such as rare earth, the magnetic force is particularly strong, and the portion of the rotor 214 and the stator 213 is extremely small. Strong magnetic attraction force is generated. However, by the same configuration as in the first embodiment, the problem caused by the strong magnetic attraction force is avoided, and as a result, the synchronous motor can effectively generate a high efficiency, thereby obtaining high energy efficiency, and at the same time, a poor connection due to the inclination of the shaft. Can be prevented to improve the reliability.

(Third embodiment)

3 is a longitudinal sectional view of a motor-driven compressor according to a third embodiment of the present invention. In addition, about the structure similar to 1st Example, the same code | symbol is attached | subjected and detailed description is abbreviate | omitted.

In FIG. 3, the sealed container 101 houses a compression mechanism portion 302 and an electric motor portion 303 for driving the compression mechanism portion.

The cylinder block 305 constituting the compression mechanism portion 302 is made of cast iron, forms a generally cylindrical compression chamber 110, and at the same time, the main bearing 320 for axially supporting the main shaft portion 116 of the shaft 104. ) And the sub bearing 121 for supporting the sub-shaft portion 118 are fixed to the cylinder block 305.

The electric motor unit 303 is an inverter-driven motor that consists of a stator 113 and a rotor 314 and is driven at a plurality of operating frequencies. The rotor 314 is fixed to the main shaft portion 116 of the shaft 104 and has a permanent magnet 315a embedded in the rotor iron core 315. The permanent magnet 315a is made of, for example, neodymium, iron, and boron-based ferromagnetic materials of rare earth magnets. In the rotor iron core 315, a hollow bore portion 306 is formed at a cross section of the compression mechanism portion 302 side. The main bearing 320 is made of aluminum alloy, which is a nonmagnetic material, and has a configuration extending into the bore portion 306 of the rotor iron core 315.

The operation of the motor-driven compressor configured as described above will be described below.

When the stator 113 is energized, the rotor 314 rotates the shaft 104, and the eccentric motion of the eccentric shaft portion 117 is transmitted to the piston 109 through the connecting rod 108 to the piston 109. Reciprocates in the compression chamber 110. As a result, the refrigerant gas is sucked and compressed from the cooling system (not shown) into the compression chamber 110, and then discharged again to the cooling system. In addition, the lubricating oil 112 is pumped up by the oil supply mechanism 111 formed in the shaft 104, and is discharged from the upper end of the shaft 104.

Here, since the permanent magnet 315a embedded in the rotor iron core 315 is made of a material having strong magnetic force such as rare earth, the magnetic force is particularly strong, and the position of the rotor 314 and the stator 113 is extremely small. Strong magnetic attraction force is generated.

When the shaft 104 receives the unbalanced load due to the magnetic attraction force generated between the rotor 314 and the stator 113, the conventional cantilever bearing has a diagonal direction with respect to the central axis of the shaft 104 of the inner wall of the main bearing. Whereas the upper and lower ends of the bearing were subjected to unbalanced loads, the structure of the supporting bearings on both sides was opposite to the sub bearing side end of the main bearing inner wall and the main bearing opposite the sub bearing inner wall diagonally with respect to the central axis of the shaft 104. The side end is used as a point to receive an unloaded load. This point-to-point distance is very long for conventional cantilever bearings. In addition, as the main bearing 320 extends inside the bore 306, the distance between the points becomes longer.

The extension of the distance between the points means that the angle at which the shaft 104 is inclined in the bearing portion becomes small, and as a result, the joining failure is less likely to occur between the bearing portion and the shaft 104, and sliding loss due to the joining failure is caused. This is avoided. This makes it possible to maintain stable high efficiency and to suppress sliding noises caused by poor bonding, thereby realizing an electric compressor with low noise.

In addition, since the load to the shaft 104 applied during the compressor operation is held on both sides of the eccentric shaft 117 (point) to which the compression load from the piston 109 is applied, it is almost equal to this point. Load distribution becomes possible, and the reliability of the sliding part of the shaft 104 can be improved compared with the cantilever type which load is concentrated only in one bearing part.

At this time, since the main bearing 320 is made of a non-magnetic material of aluminum alloy, since the magnetic force line of the permanent magnet 315a built into the rotor iron core 315 does not generate eddy current in the main bearing 320, Eddy current loss hardly occurs, and high efficiency can be achieved.

In addition, the motor unit 303 is driven by an inverter, and when the high-speed operation is executed in accordance with the load, the magnetic attraction force becomes stronger, and the force for tilting the shaft 104 becomes stronger. At this time, because of the support structure of both sides which supports the shaft 104 by the bearing of both the main bearing 320 and the sub bearing 121, the inclination of the shaft 104 can be prevented and sliding loss can be reduced. It is possible to maintain high efficiency and to prevent the failure of joining due to the inclination of the shaft, thereby improving the reliability.

In addition, the stator 113 is provided with a plurality of radially formed teeth 113b on the iron core 113a, and wound the winding 113d directly on the teeth 113b through the insulating member 113c. Since there is no coil end required for distribution winding. Therefore, the total height of the stator 113 and the rotor 314 can be made low, and it is possible to suppress the height of the electric compressor further lower. Since the overall heights of the stator 113 and the rotor 314 are low, it is easy to achieve uniformity between the stator 113 and the rotor 314, and as a result, magnetic attraction force is less likely to occur. It is possible to avoid an increase in input or noise due to the inclination.

(Example 4)

4 is a longitudinal sectional view of a motor-driven compressor according to a fourth embodiment of the present invention. In addition, about the structure similar to 3rd Example, the same code | symbol is attached | subjected and detailed description is abbreviate | omitted.

In FIG. 4, the motor unit 403 includes a stator 213 wound around a stator iron core made of a laminated electrical steel sheet, and a rotor 414 formed by providing secondary conductors to the rotor iron core 415 made of a laminated electrical steel sheet. It is a 2-pole synchronous motor composed of). The rotor iron core 415 includes a permanent magnet 415a made of, for example, neodymium, iron, and boron-based ferromagnetic materials of rare earth magnets. The rest of the configuration is the same as in the third embodiment.

The operation of the electric compressor configured as described above will be described next.

The motor unit 403 starts as an induction motor at start-up, executes synchronous drawing near the synchronous rotational speed, and performs synchronous operation. Here, since the permanent magnet 415a embedded in the rotor iron core 415 is made of a material having strong magnetic force such as rare earth, the magnetic force is particularly strong, and the permanent magnet 415a is formed at a portion where the distance between the rotor 414 and the stator 213 is small. Strong magnetic attraction force is generated.

However, by the same configuration as in the third embodiment, the problem caused by the strong magnetic attraction force is avoided, and as a result, the high efficiency of the synchronous motor can be effectively used, and high energy efficiency can be obtained, and at the same time, the failure of the joint due to the inclination of the shaft is eliminated. Can be prevented and the reliability is improved.

The present invention has the effect of providing an electric compressor having high efficiency and high reliability.

Claims (9)

In the electric compressor, (a) a motor part comprising a stator having a winding, a rotor having a rotor iron core and a permanent magnet, (b) a compression mechanism part driven by the electric motor part; The compression mechanism unit, (b-1) a shaft having an eccentric shaft portion, a main shaft portion and a minor shaft portion, wherein the main shaft portion and the minor shaft portion are disposed coaxially up and down with the eccentric shaft portion interposed therebetween; (b-2) a cylinder block having a compression chamber, (b-3) a main bearing installed in the cylinder block so as to be orthogonal to the axis of the compression chamber, and for supporting the main shaft portion; (b-4) a sub-bearing provided on the cylinder block to support the minor shaft portion; (b-5) a piston reciprocating in the compression chamber, (b-6) comprising connecting means for connecting the piston and the eccentric shaft portion, (c) a sealed container for storing lubricating oil and accommodating the electric motor part and the compression mechanism part; Motorized compressor. The method of claim 1, The main bearing includes a compression mechanism portion side end portion of the rotor iron core and does not intersect a plane perpendicular to the axis center of the main shaft portion. Motorized compressor. The method of claim 2, The main bearing is composed of iron-based material Motorized compressor. The method of claim 1, The rotor iron core has a hollow bore portion at an end portion of the compression mechanism portion, and the main bearing extends inside the bore portion. Motorized compressor. The method of claim 4, wherein The main bearing consists of a nonmagnetic material Motorized compressor. The method of claim 1, The permanent magnet is made of rare earth Motorized compressor. The method of claim 1, The motor unit is driven at a plurality of frequencies including frequencies above the commercial power source frequency Motorized compressor. The method of claim 1, The stator has a plurality of teeth and the winding is a direct winding wound through an insulating member on the teeth. Motorized compressor. The method of claim 1, The motor unit starts as an induction motor at start-up, executes synchronous drawing and executes synchronous operation when it reaches near synchronous rotation. Motorized compressor.