JP3216343B2 - Reciprocating compressor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compressor suitable for use in vehicle air conditioning, and more particularly to a multi-cylinder reciprocating compressor having a single-headed piston.

[0002]

2. Description of the Related Art In general, a compressor used for air conditioning of a vehicle is driven by an engine, and thus has a very wide range of fluctuations in the number of rotations. If the lubrication is not performed with sufficient lubrication, the life of the compressor will be greatly affected.

[0003] In compressors of the swash plate type and the oscillating plate type, which are known as reciprocating compressors, a crank chamber is usually provided so as to also serve as a reservoir for lubricating oil. It is performed in a form that depends exclusively on the oil component contained in the blow-by gas and reduced into the crankcase, and on the centrifugal flow of the stored oil.

[0004]

However, when the compressor is operated under the above-mentioned severe conditions, the heat generated by the compressor also raises the temperature of the lubricating oil and lowers the viscosity. This could lead to accidents such as seizure and gas leaks that would impair the reliability of the compressor.

For this reason, a suction port connected to a low-pressure circuit is opened in a front housing forming a crank chamber, and a low-temperature return refrigerant (suction gas) flows from the crank chamber through a cylinder block to a suction chamber of a rear housing. It has been proposed that the oil be contained in the suction gas to lubricate with the oil component contained in the suction gas. In addition, when the liquid refrigerant stagnates in the crankcase, dilution of the lubricating oil progresses, and on the contrary, the lubricating function deteriorates.

An object of the present invention is to ensure the reliability of a compressor under all operating conditions by improving a lubrication system.

[0007]

According to the present invention, there is provided a cylinder block having a plurality of bores, a front housing for forming a crank chamber and closing one end of the cylinder block, and an inner region. A rear housing that forms a suction chamber in an outer region, and closes the other end of the cylinder block via a valve plate having a suction hole and a discharge hole; and a drive shaft extending into the crank chamber. A reciprocating compressor comprising a swash plate element fixed to the swash plate element and a single-headed piston that moves directly in the bore in cooperation with the swash plate element, the swash plate element being connected to a low-pressure circuit and opening to the suction chamber. A novel configuration is adopted in which a region in the vicinity of the suction port and a region in the suction chamber farthest from the suction port communicate with the crank chamber via a conduction path.

In a preferred embodiment of the present invention, one of the conduction paths is connected to a stepped hole of the suction port for actively collecting an oil component in the return refrigerant, and a region near the suction port is provided. The conductive path connected to the front housing is formed to directly communicate with the shaft sealing device provided in the front housing.

[0009]

When the compression work is started by the single-headed piston linked to the swash plate element rotating together with the drive shaft moving in the bore, the compression work is started between the area near the suction port and the farthest area in the suction chamber. Causes a pressure difference due to flow path resistance. However, while the compressor is operating at a low speed, the pressure difference between these two areas where both passages are individually opened is relatively small and the crankcase pressure is high due to the blow-by gas, so that the blow-by The gas is recirculated to the suction chamber from both of the passages and is drawn into each of the bores as in the conventional device.

When the compressor is switched to the high-speed operation from such a state, the pressure difference between the two areas described above increases, and the pressure in the area farthest from the suction port drops significantly. In parallel with the normal gas flow sucked into the bore via the hole, a flow from a region near the suction port to the crank chamber through one conduction path and suction from the crank chamber through the other conduction path. Two gas streams occur, with the flow toward the region farthest from the mouth. As a result, the rotating sliding portion and the shaft sealing device in the crank chamber are reasonably lubricated and cooled by the low-temperature suction gas flowing through the crank chamber and the oil component contained therein.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be specifically described below with reference to the drawings. FIG. 1 shows a basic structure of a compressor according to the present embodiment. A front housing 2 is connected to a front end of a cylinder block 1 which forms a part of an outer shell of the compressor, and a suction port is provided at the rear end. A rear housing 3 in which a chamber 5 and a discharge chamber 6 are formed is connected via a valve plate 4. A drive shaft 8 connected to a power source is inserted into a crank chamber 7 formed in the front housing 2, and the drive shaft 8 is inserted into the cylinder block 1 and the front housing 2 via radial bearings 20 and 21, respectively. It is rotatably supported. A rotary swash plate 9 is fixed on a drive shaft 8 in the crank chamber 7, and a swing plate 10
Are supported so as to be relatively rotatable, and the guide portion 10 a provided on the outer edge portion is engaged with the through bolt 11 to restrain rotation, and a single-headed piston 13 in a bore 12 penetrated through the cylinder block 1. And the rocking plate 10 are connected by a connecting rod 14. Therefore, the drive shaft 8
Is converted into a back-and-forth swing of the swinging plate 10 via the rotating swash plate 9, and the single-headed piston 13 reciprocates in the bore 12, so that each suction hole 15 and a suction valve (not shown) are provided. The refrigerant gas sucked into the bore 12 from the suction chamber 5 through the outlet is discharged to the discharge chamber 6 through a discharge valve (not shown) and the discharge hole 16 while being compressed.

A boss portion 1a projecting into the crank chamber 7 is formed in the axial center portion of the cylinder block 1, and the radial bearing 20 is press-fitted into a central shaft hole formed in the boss portion 1a. The rear end of the drive shaft 8 supported by the radial bearing 20 is supported by a thrust trace 22 and a disc spring 23 housed in a center shaft hole, and the urging force of the disc spring 23 is It is received by a thrust bearing 24 interposed between the rotating housing 9 fixed to the drive shaft 8 and the front housing 2. Reference numeral 18 denotes a shaft sealing device provided inside the front housing 2.

Next, the lubrication system utilizing the suction refrigerant, which is the most characteristic of the present invention, will be described in more detail. As can be understood from FIG. 2 showing a cross section taken along the line AA of FIG. 1 and FIG. 3 showing a cross section developed along the line BB of FIG. 2, a suction flange 30 is protruded from the peripheral wall of the rear housing 3. A suction port 31 connected to the low-pressure circuit is formed in the suction flange 30, and an inner end thereof is opened to the suction chamber 5 which is annularly recessed. A series of bulging portions 32 extending in the axial direction, which are joined to the suction flange 30, are formed in outer shells of the cylinder block 1 and the front housing 2, which are integrally connected to the rear housing 3. Inlet 31
, A first conduction path 33 having a base end directly opened in the stepped hole 31a of the suction port 31 in this embodiment.
“a” penetrates the inside of the bulging portion 32, and its tip is opened to the crank chamber 7. In addition, 35 is a blind lid. on the other hand,
A second conduction path 33 b extending through the valve plate 4 and the cylinder block 1 from the region Q farthest from the opening position of the suction port 31 in the suction chamber 5 is also opened to the crank chamber 7.

Therefore, when the single-headed piston 13 linked with the swash plate element (rotating swash plate 9 and swing plate 10) rotating together with the drive shaft 8 moves directly in the bore 12, compression work is started. A pressure difference is generated between a region P in the suction chamber 5 near the suction port 31 and a region Q farthest. However, while the compressor is operating at a low speed, the pressure difference between these two regions P and Q where the first and second passages 33a and 33b are individually opened is relatively small, and the blow-by gas Because the crankcase pressure is high,
The blow-by gas flows from the two passages 33a and 33b through the suction chamber 5
And is sucked into each bore 12 as in the conventional device.

When the compressor is switched to the high-speed operation from such a state, the pressure difference between the two regions P and Q described above increases, and the pressure in the region Q farthest from the suction port 31 drops significantly. Between the suction chamber 5 and the crank chamber 7, a pressure gradient of region P> crank chamber 7> region Q is generated, and a normal gas flow sucked from the suction chamber 5 into the bore 12 through each suction hole 15. In parallel with the first conduction path 3 from the region P (the stepped hole 31a of the suction port 31 in the present embodiment).
3a, the flow toward the crankcase 7 and the crankcase 7
Then, two gas flows are generated, which flow toward the region Q through the second conduction path 33b. As a result, the low-temperature suction gas flowing through the crank chamber 7 and the oil component contained therein flow directly or through the introduction hole 17 into the rotary sliding portion and the shaft sealing device 18 in the crank chamber 7. It is supplied and acts more effectively on lubrication and cooling of the main part.

In the present embodiment, since the oil component in the return refrigerant (suction gas) easily collects in the stepped hole 31a along the circuit pipe and the inner wall of the suction port 31, the stepped hole is used. The suction gas having a higher oil content can be supplied to the crank chamber 7 by the first conduction path 33a originating from the portion 31a. FIG. 4 shows still another embodiment of the present invention. In this embodiment, the first conduction path 33a is further extended, and the tip thereof is directly connected to the shaft sealing device 18 provided in the front housing 2. It is formed so as to communicate with each other. That is, for example, the first conduction path 33a shown in the previous embodiment is connected to the sub-conduction path 33a 'formed in the front housing 2 without being opened to the crank chamber 7, and is connected to the housing chamber of the shaft sealing device 18. The sub-conduction path 33a 'is formed by sequentially connecting the perforations which are opened, specifically, provided along the outer shell of the front housing 2. In addition, 35 is a blind lid.

Therefore, the first conduction path 3
The suction gas guided by 3a and the auxiliary passage 33a 'is preferentially supplied to the shaft sealing device 18 and further lubricates and cools these elements while passing through the radial bearing 21 and the thrust bearing 24. Thereafter, the air is sucked into the corresponding bore 12 through the crank chamber 7, the second conduction path 33b, the area Q, and the suction hole 15 in the vicinity. In other words, in this embodiment, the shaft sealing device 18 that is likely to cause an accident such as gas leakage due to heat deterioration due to poor lubrication is more actively protected, and is extremely effective in extending the life of the compressor. In this embodiment, the annular groove 3 is further provided in the stepped hole of the suction port 31.
1b, the oil component flowing into the suction chamber 5 is simply stored more positively.
The configuration is such that the rate of oil return to the crank chamber 7 is further enhanced by entrusting the suction gas passing through the suction chamber.

In each of the above embodiments, only a small part of the intake gas is introduced into the crank chamber 7. Compared with the system in which the entire amount of the intake gas is introduced into the crank chamber 7 as described at the beginning, the amount of the intake gas is reduced. The amount of the oil component accompanying the flow is extremely small, and the effects on the residual oil amount in the crank chamber 7 and the problem of dilution of the lubricating oil by the stagnant liquid refrigerant are substantially insignificant.

[0019]

As described in detail above, the present invention utilizes the pressure difference created in the suction chamber to allow a part of the suction gas to flow around the crank chamber. The low-temperature suction gas and the oil component contained in the low-temperature suction gas can favorably lubricate and cool the rotating and sliding parts particularly at high rotations, and in particular, the suction gas directly passes through the shaft sealing device. With such a configuration, it is possible to preferentially and effectively protect a shaft sealing device that is extremely susceptible to deterioration.

Further, the oil component flowing along the circuit pipe and the inner wall of the suction port is positively collected in the suction port, and the collected oil component is fed to the suction gas flowing around the crank chamber and fed. Thus, the suction gas having a high oil content can be more effectively provided for lubrication.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing the entire configuration of a compressor according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a developed sectional view taken along the line BB of FIG. 2;

FIG. 4 is a sectional view similar to FIG. 3 showing another embodiment of the present invention.

[Explanation of symbols]

1 is a cylinder block, 2 is a front housing, 3 is a rear housing, 4 is a valve plate, 5 is a suction chamber, 7 is a crank chamber, 12 is a bore, 15 is a suction hole, 18 is a shaft sealing device, 31
Is a suction port, 30a is a stepped hole, 33a is a first conduction path, 3
3b is a second conduction path

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F04B 27/08

Claims (3)

(57) [Claims] 1. A cylinder block having a plurality of bores arranged side by side, a front housing forming a crank chamber and closing one end of the cylinder block, a discharge chamber in an inner area, and a suction chamber in an outer area. A rear housing for closing the other end of the cylinder block through a valve plate having a suction hole and a discharge hole, a swash plate element fixed to a drive shaft extending into the crank chamber, and the swash plate element A reciprocating compressor having a single-headed piston that linearly moves in the bore in conjunction with a suction port connected to a low-pressure circuit and opening to the suction chamber; And a region in the suction chamber, which communicates with the crank chamber via a conduction path. 2. The compressor according to claim 1, wherein one of said passages is connected to a stepped hole of said suction port for actively collecting an oil component in the return refrigerant. 3. The compressor according to claim 1, wherein the conduction path connected to the area near the suction port is formed so as to directly communicate with a shaft sealing device provided in the front housing.