JP2001214857A - Reciprocating compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reciprocating compressor having a structure for preventing a local slide and a wrench by eccentricity between a piston and a cylinder caused by an assembling error and a secular change. SOLUTION: An annular projection 11 is formed in the central vicinity of the piston 20, and a second compression space 12 is formed in response to the annular projection 11 of a cylinder body 25. At compression stroke and pressure reduction stroke, refrigerant gas in the second compression space 12 is compressed by the annular projection 11 and supplied to a sliding surface between the piston 20 and the cylinder body 25 to prevent the occurrence of the local slide and the wrench between the piston 20 and the cylinder body 25 by the action of a fluid bearing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reciprocating compressor for use in a refrigerator or an air conditioner.

[0002]

2. Description of the Related Art Reciprocating compressors, including vibrating compressors, are widely used for compressing and discharging refrigerant in refrigeration units, air conditioners, and the like. FIG. 1 shows the basic configuration of this reciprocating compressor.

In FIG. 1, a compressor body 2 includes a coil 3
c, a linear motor 3 having a movable element 9 provided with a permanent magnet 3b, a cylinder 4 having a cylinder body 15 and a cylinder head 7, a piston 5 inserted into the cylinder body 15, and a support. It is composed of a block 6 and an elastic support 8 and is elastically supported in the closed casing 1 by a plurality of suspension springs (not shown).

[0004] The piston 5 is fixed to the mover 9 of the linear motor 3 and supported by an elastic support 8.
Side peripheral surface 5a of piston 5 and inner peripheral surface 1 of cylinder body 15
5a is coated with lubricating oil. Cylinder body 15
A compression chamber 10 is formed between the inner cylinder of the cylinder 4 and the top surface 5b of the piston 5. The cylinder head 7 includes a low-pressure chamber 7a communicating with a suction pipe (not shown) and a discharge chamber (not shown). The compression chamber 10 communicates with the high-pressure chamber 7b communicating with the pipe.

[0005] The compressor having the above configuration is a linear motor 3
By supplying AC power to the coil 3c in the magnetic field of the permanent magnet 3b, the mover 9 to which the permanent magnet 3b is fixed moves straight in the axial direction of the piston 5, and the piston 5 connected to the mover 9 The reciprocating linear motion is efficiently repeated by being supported by the elastic support 8. In the case of the refrigeration cycle, the refrigerant gas guided from the suction pipe to the low-pressure chamber 7a reaches the compression chamber 10 and is compressed by the advance operation of the piston 5. After the compressed refrigerant gas is discharged into the high-pressure chamber 7b,
Discharged from the discharge pipe into the refrigeration cycle.

On the side peripheral surface of the piston 5, even if the axis of the cylinder 4 and the piston 5 is displaced due to an error in processing or assembly, a dynamic pressure is generated in a gap between the cylinder and the piston. For the purpose of preventing local sliding or twisting, a groove having one end communicating with the compression chamber 10 or a plurality of grooves having a cross-sectional area reduced or having a weir in at least one direction of the reciprocating movement and the groove are provided. Are formed.

[0007]

However, the viscous force is dominant in the gap of the order of μm between the piston 5 and the cylinder 4, and the moving speed of the piston 5 and the generated dynamic pressure coincide with each other. Regardless of the grooves provided on the side peripheral surface, the velocity of the piston 5 becomes zero or near zero at the top dead center and the bottom dead center of the piston 5, so that the dynamic pressure also becomes zero or near zero. When such a state is continued, local sliding and twisting occur between the piston 5 and the cylinder 4.

[0008] Also, when the shaft center between the stator 13 and the mover 9 of the linear motor 3 is displaced, if the force such as the magnetic attraction force becomes larger than the dynamic pressure generated by the groove, the same applies. Then, local sliding and prying occur between the piston 5 and the cylinder 4.

The sliding or twisting between the piston 5 and the cylinder 4 increases the loss of the piston movement, resulting in a decrease in the efficiency of the compressor and a decrease in reliability such as wear of the sliding portion.

SUMMARY OF THE INVENTION An object of the present invention is to provide a reciprocating compressor having a structure for preventing local sliding and twisting between a cylinder and a piston.

[0011]

According to a first aspect of the present invention, a piston inserted into a cylinder is driven forward and backward to compress and discharge the fluid sucked into the cylinder. In the reciprocating compressor, a space is formed near the center of a sliding surface where the cylinder and the piston face each other, and a protrusion is formed on the cylinder or the piston so as to divide this space into two in the direction of movement of the piston. Thus, each volume in the space divided into two by the forward and backward movement of the piston is configured to relatively change, and the space formed on the sliding surface between the cylinder and the piston is Since it is divided into two parts by the protruding portion, the fluid in the space narrowed by the reciprocating movement of the piston is compressed to a high pressure and supplied to the sliding surface, and the fluid is locally applied to the sliding surface. It can be specific sliding and twisting is prevented from occurring. Therefore, wear of the sliding surface due to displacement of the axis of the piston with respect to the cylinder and reduction in efficiency of the compressor are suppressed.

In the above configuration, even if the space is formed on the cylinder side and the space is divided into two by the protruding portion projecting from the piston side, the space is formed on the piston side,
The same effect can be obtained even if the space is divided into two parts by the protruding portions protruding from the cylinder side.

Further, by forming a communication path from each of the two divided spaces to the sliding surface between the cylinder and the piston, the compressed and high-pressure fluid can easily flow to the sliding surface through the communication path. In addition, the effect of suppressing the occurrence of sliding and twisting can be increased.

According to a second aspect of the present invention, a piston inserted into a cylinder is connected to a movable element of a linear motor arranged coaxially with a moving axis of the piston, and the piston is reciprocated by the linear motor. In a reciprocating compressor that compresses and discharges the fluid sucked into the cylinder by driving the movable member back and forth, a fixed member and a movable member that are coupled to the cylinder and disposed at a position surrounding the movable member are provided. ,
A rolling bearing for regulating the position of the reciprocating movement of the mover is provided, and a rolling bearing is provided between the mover connected to the piston and the fixed body connected to the cylinder. Because the mover does not become eccentric due to the change in magnetic force, the position of the connected piston in the cylinder does not change, and the sliding surface between the piston and the cylinder can be locally slid. The occurrence of prying is prevented.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings to provide an understanding of the present invention.
The embodiment described below is an example embodying the present invention, and does not limit the technical scope of the present invention. This embodiment shows a reciprocating compressor used for compressing refrigerant gas in a refrigeration cycle.

In the configuration of the reciprocating compressor shown in FIG. 1, when there is a deviation between the axis of the cylinder body 15 and the axis of the piston 5, or when the stator 13 and the movable element 9 of the linear motor 3 are displaced. As described above, when the shaft center is shifted from the above, local sliding or twisting occurs in the sliding portion between the cylinder body 15 and the piston 5. To solve this,
In the first embodiment, as shown in FIG. 2, a structure of a cylinder body 25 and a piston 20 is employed instead of the cylinder body 15 and the piston 5 shown in FIG. The other configuration is the same as that shown in FIG.

In FIG. 2, an annular projection (projection) 11 is formed in the vicinity of the center of the side peripheral surface of the piston 20 in a flange shape. Two compression chambers (spaces) 12 are formed.
The gap between the outer diameter of the annular projection 11 and the inner diameter of the second compression chamber 12 is several tens of μm while the gap between the outer diameter of the piston 20 and the inner diameter of the cylinder body 25 is 10 to 20 μm.
It is preferable to set the thickness to a few hundred μm.

When the cylinder body 25 and the piston 20 are applied to the configuration shown in FIG. 1 and the piston 20 is driven forward and backward by the linear motor 3, refrigerant gas (fluid) flows from the compression chamber 10 into the second compression chamber 12. During the compression process in which the piston 20 is flowing and the piston 20 advances in the direction of the cylinder head 7, the refrigerant gas in the second compression chamber 12 is compressed by the annular projection 11 to a high pressure, and the cylinder body 25 and the piston 2
0 is supplied to the sliding surface. At this time, the piston 20 is eccentric with respect to the cylinder body 25, and a gap is generated between the eccentric side and the opposite side, and a pressure difference is generated due to the effect of the throttle. As a result, the function of the hydrostatic bearing acts on the piston 20. In the pressure reducing step in which the piston 20 is retracted, the refrigerant gas in the second compression chamber 12 is supplied between the cylinder body 25 and the piston 20 by the compression of the annular projection 11, so that the action of the fluid bearing on the piston 20 is achieved. Works. Even when the shaft center is displaced by the action of the fluid bearing, local sliding and twisting are prevented.

As shown in FIG. 3, the second compression chamber 17
The refrigerant gas in the second compression chamber 17 is compressed by the reciprocating movement of the piston 20 by forming a refrigerant gas supply groove (communication passage) 16 extending from the contact hole to the sliding surface with the piston 20, and the refrigerant gas supply groove (communication path) is narrowed. Since the pressure is increased by being supplied to the piston 16 and supplied to the sliding surface with the piston 20,
A more effective action of the fluid bearing is performed, and local sliding and twisting are prevented.

Each of the above-described structures is an example in which the second compression chambers 12 and 17 are formed on the cylinder bodies 25 and 26, but the second compression chamber 23 may be formed on the piston 21 side as shown in FIG. it can. Further, the coolant gas supply grooves 18 connected to the sliding surfaces from both sides of the second compression chamber 23 can be formed. Also in this configuration, since the coolant gas is supplied to the sliding surface with the cylinder body 27, the fluid bearing acts to prevent local sliding and twisting.

FIG. 5 shows the structure of the second embodiment. A movable element 9 is provided between a movable element 9 constituting the linear motor 3 and a support block 6 constituting an outer shell of the compressor body 2. A rolling bearing 30 for guiding the reciprocating direction of the roller is provided. The other configuration is the same as the configuration shown in FIG.

A coil 3 is provided between the permanent magnet 3b provided on the mover 9 and the coil 3c provided on the stator 13.
The magnetic force acts when AC power is applied to the movable member 9c. However, if a displacement occurs between the axis of the mover 9 and the axis of the stator 13, biased magnetic attraction acts to cause the mover 9 to move. A force for moving the axis acts to exert a force for moving the axis of the piston 5. Since the position of the mover 9 is regulated by the rolling bearing 30 as in this configuration, the mover 9 is held in position without being eccentric, and the eccentricity of the piston 5 is prevented. Therefore, local sliding and twisting between the piston 5 and the cylinder body 15 due to the eccentricity of the mover 9 due to an assembly error or aging can be prevented.

[0023]

As described above, according to the present invention, local sliding and twisting due to a deviation between the axis of the cylinder and the axis of the piston due to an assembly error or aging can be prevented. In addition, it is possible to provide a reciprocating compressor in which a reduction in efficiency due to an increase in sliding loss and abrasion of sliding parts are suppressed.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a basic configuration of a reciprocating compressor.

FIG. 2 is an essential part cross-sectional view showing the configuration of the reciprocating compressor according to the first embodiment.

FIG. 3 is an essential part cross sectional view showing another mode of the first embodiment;

FIG. 4 is an essential part cross sectional view showing another mode of the first embodiment;

FIG. 5 is a sectional view showing a configuration of a reciprocating compressor according to a second embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Compression chamber 11, 19 Annular protrusion (projection part) 12, 17, 23 Second compression chamber (space) 16, 18 Refrigerant gas supply groove (communication path) 20, 21 Piston 25, 26 Cylinder main body 30 Rolling bearing

Continued on the front page (72) Inventor Akiju Mori 1006 Kazuma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor Takafumi Asada 1006 Oji Kadoma Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd. (72) Invention Person Takao Yoshimura 4-5-2-5 Takaidahondori, Higashiosaka City, Osaka Prefecture Inside Matsushita Refrigerating Machinery Co., Ltd. (72) Inventor Sadao Kawahara 1006 Kazuma Kadoma, Kadoma City, Osaka Prefecture F-term (reference) 3H076 AA02 BB17 BB26 CC03 CC31

Claims (5)

[Claims] 1. A reciprocating compressor for compressing and discharging fluid sucked into a cylinder by driving a piston inserted into the cylinder to advance and retreat, wherein a sliding surface between the cylinder and the piston is formed. A space is formed near the center, and a protrusion is formed on the cylinder or piston so as to divide this space into two in the direction of movement of the piston, so that each volume in the space divided into two by the movement of the piston moves relative to each other. A reciprocating compressor characterized in that it is configured to change in a dynamic manner. 2. The reciprocating compressor according to claim 1, wherein the space is formed as a concave portion on the cylinder side, and the space is divided into two by a protruding portion projecting from the piston side toward the concave portion. 3. The reciprocating compressor according to claim 1, wherein the space is formed as a concave portion on the piston side, and the space is divided into two by a projecting portion projecting from the cylinder side toward the concave portion. 4. The reciprocating compressor according to claim 1, wherein a communication passage is formed from each of the two divided spaces to a sliding surface between the cylinder and the piston. 5. A cylinder which is connected to a mover of a linear motor which is arranged coaxially with a reciprocating movement axis of a piston inserted in the cylinder, and drives the piston forward and backward by reciprocating movement of the mover by the linear motor. A reciprocating compressor that compresses and discharges fluid sucked into the cylinder, wherein a reciprocating movement of the mover is provided between a fixed body and the mover that are coupled to the cylinder and disposed at a position surrounding the mover. A reciprocating compressor comprising a rolling bearing for regulating a position.