JP2013068188A - Electric compressor - Google Patents

Abstract

An electric compressor capable of efficiently lubricating a sliding portion even after liquid compression at start-up without causing an increase in cost and an increase in size of a main casing.
A compression shaft includes a drive shaft for driving the orbiting scroll to rotate relative to a fixed scroll, a main bearing member for supporting the drive shaft, and an Oldham ring for preventing rotation of the orbiting scroll. When liquid compression occurs at the time of startup, the compression mechanism portion is provided with one or a plurality of pores 16 that exclude high-pressure liquid refrigerant into the high-pressure space 11 in the main body casing. Efficiently removing the liquid refrigerant that has entered the sliding part of the Oldham ring 7 when it occurs can ensure lubricity, and the sliding part can be configured with inexpensive parts with low lubrication performance, and is small and inexpensive. It can be set as a simple electric compressor.
[Selection] Figure 1

Description

  The present invention relates to an electric compressor in which a housing is provided with a compression mechanism portion that sucks, compresses and discharges refrigerant, and a motor that drives the compression mechanism portion.

  Conventionally, there is a scroll compressor as one of the electric compressors of this type, and the electric scroll compressor shown in FIG.

  In this electric scroll compressor, a compression mechanism portion 2 and an electric motor 3 are arranged in a main body casing 1, and a portion where the electric motor 3 is arranged is a high-pressure space 11. The compression mechanism 2 includes a fixed scroll 4 having a fixed spiral blade 4a and a swirl spiral blade 5a that meshes with the fixed spiral blade 4a of the fixed scroll 4 to form a plurality of compression spaces 10 on the swivel end plate 5b. The formed orbiting scroll 5 is configured as a main element.

 A main bearing member 6 provided at a position sandwiching the orbiting scroll 5 between the fixed scroll 4, an Oldham ring 7 for preventing the orbiting scroll 4 from rotating, and an orbiting end plate 5 b of the orbiting scroll 5. A drive shaft 8 having an eccentric shaft portion 8a that fits in the provided orbiting bearing portion 20 and orbits the orbiting scroll 5, and a main bearing portion 21 that is provided on the main bearing member 6 and supports the drive shaft 8. Similarly, the main bearing member 6 divides the orbiting bearing side space of the orbiting end plate 5b of the orbiting scroll 5 into an intermediate pressure space 12 that is substantially close to the discharge pressure and a low pressure space 13 that is slightly higher than the suction pressure. Are arranged.

 An oil sump 23 is provided at the bottom of the main body casing 1, and oil in the oil sump 23 passes through an oil supply path 8 b that passes through the drive shaft 8 by a pump 24 installed on the side of the sub-bearing portion 22 of the drive shaft 8. The Oldham ring 7 disposed in the low-pressure space 13 is supplied to the end portion of the eccentric shaft portion 8a and lubricates the orbiting bearing portion 20 and then through the pores 5c provided in the orbiting end plate 5b of the orbiting scroll 5. The compressed space 10 is lubricated through the pores 5d (see, for example, Patent Document 1).

 In such an electric scroll compressor, when the rotational force of the electric motor 3 is transmitted through the drive shaft 8, the low-temperature and low-pressure fluid sucked from the suction passage 14 of the compression mechanism section 2 is compressed into a plurality of compressions. The space 10 is compressed while moving from the outer peripheral side to the center in the space 10 and discharged from the discharge hole 15 as a high-temperature and high-pressure fluid, which is repeated.

 By supplying oil to the Oldham ring 7, sliding loss between the main bearing member 6 and the key groove portion 6a provided on the orbiting end plate 5b of the orbiting scroll 5 is reduced, and a buffering effect due to oil viscosity is provided. Therefore, vibration was reduced.

JP-A-9-217689

However, in the above-described conventional configuration, when a so-called liquid compression phenomenon occurs in which the liquid refrigerant is compressed, the liquid refrigerant that has flowed back through the pores 5d from the compression space 10 invades and stays in the low pressure space 13 due to excessive pressure. As a result, the oil supply to the high pressure low pressure space 13 is hindered, and the sliding loss of the Oldham ring 7 may increase, which may temporarily degrade the performance.

 The present invention solves such a conventional problem, and by efficiently discharging the liquid refrigerant retained in the low-pressure space during liquid compression, even if liquid compression occurs, the sliding loss of the Oldham ring. An object of the present invention is to provide a highly efficient and highly reliable electric compressor.

  In order to solve the above-described conventional problems, the present invention provides one or a plurality of high-pressure liquid refrigerants that are excluded from the high-pressure space in the main body casing when liquid compression occurs in the compression mechanism when the compression mechanism is activated. In this configuration, a single pore is provided.

 As a result, the low pressure space is not filled with the high pressure liquid refrigerant after the liquid compression, and oil is supplied to the low pressure space immediately after the start of the normal compression, and the sliding loss of the Oldham ring can be kept low.

  The electric compressor according to the present invention can suppress the sliding loss of the Oldham ring even when liquid compression occurs at the time of start-up, and can realize high efficiency and high reliability.

Sectional drawing of the electric compressor in Embodiment 1 of this invention The expanded sectional view of the principal part of the electric compressor in Embodiment 1 The perspective view of the keyway part in Embodiment 1 (A) Operation explanatory diagram at the time of starting the valve in the main part of the first embodiment, (b) Operation explanatory diagram at the time of normal operation Cross section of a conventional electric compressor

  A first invention includes a compression mechanism having a fixed scroll and a turning scroll, a main body casing incorporating an electric motor for driving the compression mechanism, a drive shaft for driving the turning scroll by a driving force of the electric motor, and the drive. A high-pressure liquid refrigerant generated by liquid compression when liquid compression occurs when the compression mechanism section is activated, including a main bearing member that supports a shaft and an Oldham ring for preventing the orbiting scroll from rotating. In the high-pressure space in the main body casing, the compression mechanism portion is provided with one or a plurality of pores.

According to a second aspect of the present invention, there is provided a compression mechanism having a fixed scroll and a turning scroll, a main body casing incorporating an electric motor for driving the compression mechanism, a driving shaft for turning the turning scroll by a driving force of the electric motor, and the driving. A main bearing member for supporting a shaft, a key groove provided in the main bearing member so as to communicate with a compression space formed by the fixed and orbiting scroll, and the rotation of the orbiting scroll by sliding the key groove. An Oldham ring for preventing the liquid, and the main bearing member is provided with a pore communicating with the key groove portion and the high-pressure space in the main body casing. The high-pressure liquid refrigerant generated by the compression and staying in the key groove portion is excluded to the high-pressure space in the main body casing.
According to these first and second inventions, even when liquid compression occurs during startup and liquid refrigerant enters the key groove in the low pressure space, the differential pressure between the high pressure liquid refrigerant and the high pressure space that is low pressure immediately after startup. Thus, the liquid refrigerant is discharged from the pores to the high pressure space, and the high pressure liquid refrigerant is prevented from staying in the low pressure space, so that the oil can be easily supplied, and the sliding loss of the Oldham ring can be kept low.

According to a third invention, in the second invention, a valve that opens and closes by a differential pressure is provided in an opening on the high-pressure space side of the pore. As a result, during normal operation, the valve is closed by the differential pressure between the high-pressure space that is high pressure by the discharge gas and the low-pressure space close to the suction pressure, and the discharge gas can be prevented from flowing back into the low-pressure space.
At this time, if the valve provided in the opening on the high-pressure space side of the pore is configured using an inexpensive material such as a steel ball, the backflow of the discharge pressure can be prevented by an inexpensive method.

 According to a fourth invention, in the second or third invention, the openings on the key groove side of the pores are arranged so as not to be shielded by the Oldham ring, and the liquid refrigerant is efficiently discharged by securing the discharge path. Liquid refrigerant can be discharged.

  According to a fifth aspect of the present invention, in the first to fourth aspects of the present invention, a fluid containing a carbon dioxide as a main component is used as a fluid, and has recently been promoted from the viewpoint of environmental protection and is used at high pressure. It is possible to cope with a refrigerant mainly composed of carbon.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments. For convenience, the same parts as those in the conventional example will be described with the same reference numerals.

(Embodiment 1)
FIG. 1 is a sectional view of an electric compressor according to an embodiment of the present invention. FIG. 1 shows one example in the case of a horizontal electric compressor installed sideways by a mounting leg 30 around the body of the electric compressor.
As shown in FIG. 1, this electric compressor incorporates an electric motor 3 in a main body casing 1, and drives a compression mechanism portion 2 fitted or press-fitted into the main body casing 1. The electric motor 3 is driven by an electric motor drive circuit unit 32 incorporated in the sub casing 31. Further, an oil sump 23 is provided in the main body casing 1 for storing a liquid used for lubrication of each sliding portion including the compression mechanism portion 2. The refrigerant handled during normal operation is a gas refrigerant, and a liquid such as oil is used as a liquid to be used for lubrication of each sliding part and a seal of the sliding part of the compression mechanism part 2. The oil is compatible with the refrigerant.

A main bearing member 6 having a pump 24, a sub-bearing portion 22, an electric motor 3, and a main bearing portion 21 from the one end discharge port 25 side is disposed in the main body casing 1 in the axial direction. The pump 24 is held between the lid body 26 and a pump chamber 27 communicating with the oil reservoir 23 is formed inside the lid body 26 so as to communicate with the oil reservoir 23 through the suction passage 28. The auxiliary bearing portion 22 is supported by the main body casing 1 and pivotally supports the side of the drive shaft 8 connected to the pump 24. Further, the electric motor 3 is configured such that the stator 3a is shrink-fitted and fixed to the main casing 1 or is fixed by an annular member so that the drive shaft 8 can be rotationally driven by the rotor 3b fixed around the drive shaft 8. Yes.
The main bearing member 6 is fixed by a fixed scroll 4 and a bolt (not shown) or the like, and is clamped by the sub casing 31 located on the other end opening side of the main body casing 1, and the compression mechanism portion 2 side of the drive shaft 8 is held on the main bearing. It is pivotally supported by the part 21. Further, a scroll compressor is configured by sandwiching the orbiting scroll 5 between the main bearing member 6 and the fixed scroll 4. An Oldham ring 7 is provided between the main bearing member 6 and the orbiting scroll 5 to prevent the orbiting scroll 5 from rotating and circularly move, and the drive shaft 8 is connected to the orbiting scroll 5 via an eccentric bearing portion 20. Thus, the orbiting scroll 5 can be turned on a circular orbit.

  The oil supplied from the pump 24 is supplied to the end portion of the eccentric shaft portion 8a through an oil supply passage 8b penetrating the drive shaft 8, lubricated the orbiting bearing portion 20, and then provided on the orbiting end plate 5b of the orbiting scroll 5. The Oldham ring 7 disposed in the low pressure space 13 is lubricated through the pores 5c, and the compression space 10 is lubricated through the pores 5d.

  The key groove portion 6a on which the Oldham ring 7 slides is provided with a pore 16 that passes through the main bearing member 6 and communicates with the high-pressure space 11 in which the electric motor 3 is disposed. Even when a liquid refrigerant enters, the liquid refrigerant can be discharged to the high-pressure space 11 side due to a differential pressure with respect to the high-pressure space 11 that is in a low-pressure state without high-pressure discharge gas at the time of startup.

  With the above configuration, even when liquid compression occurs during startup and high-pressure liquid refrigerant intrudes into the key groove portion 6a, which is originally a low-pressure space, the liquid refrigerant is in the pores because there are pores 16 communicating with the high-pressure space 11. 16, the high-pressure space 11 is excluded, and high-pressure liquid refrigerant can be prevented from staying in the low-pressure space 13. For this reason, the oil supplied from the pump 24 is supplied to the low-pressure space 13 without being obstructed by the high-pressure liquid refrigerant, and good lubrication of the Oldham ring 7, the key groove portion 6a, and the compression space 10 can be realized.

In addition, the pore 16 is provided with a valve that opens and closes by a differential pressure. Hereinafter, this configuration will be described. 2 is a cross-sectional view of the pore 16 of the main bearing member 6 in the embodiment of the present invention, FIG. 3 is a perspective view of the key groove portion 6a, and FIGS. Shows the opened and closed state.
In each figure, the valve 17 is constructed by inserting a steel ball 17a into a stepped portion of the pore 16 formed in the main bearing member 6 and fitting a push nut 17b. That is, the valve 17 has a shape in which a step portion 17c extending from the key groove portion 6a side to the high-pressure space 11 side is provided in the middle of the pore 16 and a seal portion is configured by grounding with the steel ball 17a.

 The valve opening / closing operation in the above-described configuration will be described below. When liquid compression occurs during startup and high-pressure liquid refrigerant enters the key groove portion 6a, which is originally a low-pressure space, high-pressure discharge gas for startup The valve 17 is opened in such a manner that the steel ball 17a is pressed against the push nut 17b by the differential pressure with the high pressure space 11 which is in a low pressure state (the steel ball 17a not shown is pressed against the right side of the push nut 17b). In this case, the hole 17d is configured to be in an open state), and the liquid refrigerant is removed into the high-pressure space 11 by the pores 16 communicating with the high-pressure space 11. On the other hand, during normal operation, the high-pressure discharge gas fills the high-pressure space 11 and becomes higher than the key groove portion 6a, which is a low-pressure space, so that the valve 17 is pressed against the stepped portion 17c. It is closed and the backflow of the discharge gas to the low pressure space 13 can be prevented.

  In this way, liquid compression occurs at the time of start-up, and even if high-pressure liquid refrigerant enters the key groove portion 6a that is originally a low-pressure space, it can be effectively eliminated. Accordingly, it is possible to prevent insufficient lubrication of the key groove portion due to stagnation of high-pressure liquid refrigerant with a simple configuration, and it is possible to maintain functions during normal operation with a small and inexpensive valve structure. This lubrication deficiency prevention effect can be achieved with a configuration in which the pore 16 and the valve 17 are provided in a part of a conventional compression mechanism, and a special configuration for increasing the lubrication effect is newly added. There is no need and it can be set as a small and cheap electric compressor.

 Further, the pore 16 is configured at a position not shielded by the Oldham ring 7 disposed in the key groove portion 6a, and is suitable for removing high-pressure liquid refrigerant regardless of the operation of the Oldham ring 7.

 Furthermore, it is possible to cope with an electric compressor using a refrigerant mainly composed of carbon dioxide, which has been promoted from the viewpoint of environmental protection in recent years, and mainly comprises carbon dioxide having a higher pressure than conventional refrigerants. It is suitable for improving the efficiency and reliability of an electric compressor using a refrigerant and reducing the size and weight.

  As described above, the electric compressor according to the present invention can suppress the sliding loss of the Oldham ring even if liquid compression occurs at the time of starting, and can realize high efficiency and high reliability. In particular, if the structure as in claim 2 is used, the compression space as well as the keyway part of the Oldham ring can be efficiently lubricated with a simple structure, and inexpensive parts can be adopted, and the cost can be reduced and the reliability of the compression mechanism part can be achieved. In addition, the size and weight can be reduced. As a result, it can be mounted on an engine and can be widely applied to environmental vehicles such as hybrid vehicles.

DESCRIPTION OF SYMBOLS 1 Main body casing 2 Compression mechanism part 3 Electric motor 4 Fixed scroll 5 Orbiting scroll 6 Main bearing member 6a Key groove part 7 Oldham ring 8 Drive shaft 10 Compression space 11 High pressure space 13 Low pressure space 17 Valve

Claims (5)

A compression mechanism having a fixed scroll and an orbiting scroll, a main body casing incorporating an electric motor for driving the compression mechanism, a drive shaft for orbiting the orbiting scroll by the driving force of the electric motor, and a main bearing for supporting the drive shaft A bearing member and an Oldham ring for preventing rotation of the orbiting scroll, and when liquid compression occurs when the compression mechanism is activated, the high-pressure liquid refrigerant generated by the liquid compression is contained in the main casing. An electric compressor provided with one or a plurality of pores excluded in a high-pressure space in the compression mechanism section. A compression mechanism having a fixed scroll and a turning scroll, and a main body casing incorporating an electric motor for driving the compression mechanism, a drive shaft for turning the turning scroll, a main bearing member for supporting the drive shaft, and the fixed A key groove portion provided in the main bearing member so as to communicate with a compression space formed by the orbiting scroll, and an Oldham ring that slides on the key groove portion to prevent the orbiting scroll from rotating, and the main bearing. When the member is provided with one or a plurality of pores communicating with the key groove portion and the high-pressure space in the main body casing, and the liquid compression occurs when the compression mechanism portion is activated, the key groove portion is generated by the liquid compression. An electric compressor characterized in that a high-pressure liquid refrigerant staying in the chamber is excluded to a high-pressure space in the main casing. 3. The electric compressor according to claim 2, wherein a valve that opens and closes with a differential pressure is formed in the middle of the pores, and is closed during normal operation to prevent backflow of the discharge gas. 4. The electric compressor according to claim 2, wherein the pore is configured at a position that is not shielded by an Oldham ring disposed in the key groove portion. The electric compressor according to any one of claims 1 to 4, wherein a refrigerant mainly containing carbon dioxide is used.