JPH051673A - Reciprocating compressor for on-vehicle air conditioner - Google Patents

Abstract

PURPOSE:To provide excellent responsiveness to prevent effectively the occurrence of seizure just after starting. CONSTITUTION:A device is equipped with a bypass passage 83 bypassing compressed refrigerant gas with discharge side 82 communicated with the suction side 81, and with a ball valve 43 acting as an initial lock prevention valve which senses bore-pressure introduced from respective bores 5a and 5b through check valves 31 and 32, so that an increase in pressure within the respective bores forces the bypass passage to be opened just after starting.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reciprocating compressor suitable for air conditioning of a vehicle, and more particularly to a reciprocating compressor for vehicle air conditioning in which seizure is prevented immediately after starting.

[0002]

2. Description of the Related Art As a conventional reciprocating compressor for vehicle air conditioning, for example, a swash plate compressor disclosed in Japanese Patent Laid-Open No. 54-108008 is known. In this swash plate type compressor, a pair of cylinder blocks are provided in front and in back so as to form a swash plate chamber communicating with the return refrigerant suction port at the connecting portion. Both outer ends of the cylinder block are closed by a housing via valve plates, and a suction chamber and a discharge chamber communicating with the swash plate chamber are formed in the housing. A drive shaft is inserted into and supported by a common central shaft hole of each cylinder block, and a swash plate fixed to the drive shaft is rotatably accommodated in a swash plate chamber. In addition, a plurality of pairs of front and rear bores arranged in parallel around the drive shaft are formed in the cylinder block, and a double-headed piston moored to the swash plate via shoes is linearly inserted into each bore. .. Further, each cylinder block is formed with a plurality of suction passages (not shown) that connect the swash plate chamber and the suction chamber of each housing,
A discharge passage that connects one discharge chamber and the other discharge chamber is also formed.

Reciprocating compressors such as this type of swash plate type compressor and rocking swash plate type compressors are connected to a refrigerating circuit and driven by an electromagnetic clutch to be mounted on a vehicle. It is used as an air conditioner. In such a general air conditioner, the high-temperature and high-pressure refrigerant gas discharged from the reciprocating compressor is liquefied by a condenser and expanded by an expansion valve to form a low-temperature, low-pressure mist, and the latent heat is generated by an evaporator. After cooling the ambient air, it is sucked into the reciprocating compressor again.

[0004]

However, in a vehicle air-conditioning compressor, the inside of the compressor is lubricated with a mist-like lubricating oil contained in the refrigerant gas. Therefore, if such a compressor is restarted after being stopped for a long time, each bore will perform compression while the liquid refrigerant and the lubricating oil are stored in the compressor due to the temperature difference of each part of the refrigeration circuit that is stopped. Becomes In this case, the liquid compression in each bore causes almost all of the lubricating oil in the compressor to flow into the refrigeration circuit, leaving the compressor in a non-lubricated state until the lubricating oil makes one circuit in the refrigeration circuit. With a plate compressor, seizure is required for a few seconds after startup, such as the sliding surface between the bore and the double-headed piston, the sliding surface between the swash plate and the shoe, and the engagement surface between the shoe and the double-headed piston. May occur.

Therefore, the present applicant has proposed a compressor capable of effectively preventing seizure immediately after starting (Japanese Patent Application No.
245684). This compressor has a bypass passage for communicating a discharge side and a suction side and bypassing a compressed refrigerant gas, and an atmospheric pressure and a suction pressure are opposed to each other. And an initial lock prevention valve for opening.

However, in the above proposed compressor, since the initial lock prevention valve senses a decrease in suction pressure immediately after starting, even if liquid compression is actually performed in each bore, the suction pressure decreases. If the value is very small, the bypass passage may not be opened, and the response may not be sufficient. An object of the present invention is to effectively prevent seizure immediately after startup under excellent responsiveness.

[0007]

In order to solve the above-mentioned problems, a reciprocating compressor for vehicle air conditioning according to the present invention has a bypass passage for communicating a discharge side and a suction side to bypass compressed refrigerant gas. A novel means is adopted, which is provided with an initial lock prevention valve that senses the pressure in the bore introduced from each bore via the check valve and opens the bypass passage due to the rise in the pressure in the bore immediately after startup. ..

[0008]

When the compressor is stopped for a long time and then restarted, when the liquid refrigerant and the lubricating oil are compressed in each bore,
Since the liquid lubricating oil is an incompressible fluid, the pressure inside the bore rises. In the reciprocating compressor for vehicle air conditioning of the present invention, the initial anti-lock valve opens the bypass passage with better response than the conventional sensing of the decrease in suction pressure due to the increase in the bore pressure. Since the check valve is interposed between each bore and the initial lock prevention valve, the internal pressure of the bore does not flow backward from the bore in the compression stroke to the bore in the suction stroke. Therefore, at this time, the lubricating oil is supplied from the discharge side to the suction side through the bypass passage without passing through the refrigeration circuit, so that the inside of the compressor is hardly lubricated and seizure occurs in the lubrication necessary part. Will not occur.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the reciprocating compressor for vehicle air conditioning according to the present invention is embodied as a swash plate compressor will be described below with reference to the drawings. In this swash plate compressor, as shown in FIG. 1, a cylinder block 1 is formed by joining a pair of front and rear blocks 1a and 1b to each other, and a swash plate chamber 2 is formed at the center of the inside thereof, and both front and rear end surfaces are formed. Front housing 3
Also, the rear housing 4 is connected, and center housings 5 and 6 are provided on the outer circumference. Cylinder block 1
Has a plurality of pairs of bores 5a, 5b formed at opposite positions on the front and rear sides of the swash plate chamber 2, and the drive shaft 7 is rotatably supported on an axis parallel to the bores 5a, 5b. There is. The swash plate 12 fixed to the drive shaft 7 is rotatably accommodated in the swash plate chamber 2, and the swash plate 12 has a shoe 13
A double-headed piston 6 is moored through the double-headed piston 6, and the double-headed piston 6 is reciprocally housed in each of the bores 5a and 5b.

Valve plates 20 and 21 are interposed between the cylinder block 1 and the front and rear housings 3 and 4, and suction chambers 22 and 23 and discharge chambers 24 and 25 are formed in the front and rear housings 3 and 4, respectively. ing. The front suction chamber 22 communicating with the swash plate chamber 2 through the front suction passage 26 formed in the cylinder block 1 has a front bore through a suction valve mechanism (not shown) provided in the valve plate 20. The bore 5a communicates with the front side discharge chamber 24 through a discharge valve mechanism (not shown). On the other hand, the rear suction chamber 23, which communicates with the swash plate chamber 2 through the rear suction passage 27 formed in the cylinder block 1, also has the rear bore 5b through the similar suction valve mechanism provided in the valve plate 21. The bore 5b is also communicated with the rear side discharge chamber 25 via the discharge valve mechanism. The discharge chamber 24 on the front side and the discharge chamber 25 on the rear side are communicated with each other by a discharge passage (not shown).

The cylinder block 1 has front and rear bores 5a,
Check valves 31 and 32 that communicate with 5b are provided. The check valves 31, 32 are balls 31a, 32a which can be seated on the side of the bores 5a, 5b and the balls 31a, 32.
It is composed of springs 31b and 32b for biasing a. Spring 31
The spring chamber accommodating b and 32b is a center housing 5,
6 are communicated with each other by through holes 33 formed in the center housing 6, and the through holes 33 are communicated with each other by through holes 34 formed in the inner periphery of the center housing 6.

The center housing 6 together with the flange 1c, as shown in FIG. 2, has a bore pressure sensing chamber 80, a low pressure chamber 81, a high pressure chamber 82, and a bypass passage 83 for communicating the low pressure chamber 81 with the high pressure chamber 82. And form. The bore pressure sensing chamber 80 is connected to the through hole 34 and the pressure sensing hole 35, and the bore pressure is supplied from each of the bores 5a and 5b. The low-pressure chamber 81 has the low-pressure passage 28 and the rear suction passage 2
It is connected to the swash plate chamber 2 via 7 and is supplied with suction pressure. The high-pressure chamber 82 is connected to the front and rear discharge chambers 24 and 25 by a high-pressure passage 29, and a discharge pressure is supplied. The pressure sensing chamber 80 in the bore and the low pressure chamber 81 are communicated with each other by a bypass passage 83. The bypass passage 83 is equipped with a spool 41 slidably on the side of the pressure sensing chamber 80 in the bore, and is connected to the spool 41. The rod 42 is connected to a ball valve 43 as an initial lock prevention valve. The ball valve 43 is provided in the low pressure chamber 81 while being urged by the spring 44 so as to close the bypass passage 83 in a normal state. Further, the high pressure chamber 82 is
As shown in FIG. 3, it is connected to the condenser 101 of the refrigeration circuit. The condenser 101 is connected to the expansion valve 102, the expansion valve 102 is connected to the evaporator 103, and the evaporator 103 is again connected to the low pressure chamber 81 of the swash plate compressor via the suction throttle valve mechanism 104.

The swash plate type compressor having the above-described structure is provided with an engine (not shown) via an electromagnetic clutch (not shown).
When the drive shaft 7 shown in FIG. 1 is driven by
The swash plate 12 rotates integrally with the drive shaft 7 and oscillates, and the double-headed piston 6 is engaged with the bore 5 via the shoe 13.
It reciprocates in a and b. The return refrigerant gas introduced from the refrigeration circuit enters the swash plate chamber 2 via the low pressure chamber 81 as the double-headed piston 6 reciprocates, and enters the front and rear bores 5a, 5b via the front and rear suction passages 26, 27, respectively. Inhaled and subject to compression. Then, the refrigerant gas discharged from both the bores 5a, 5b into the discharge chambers 24, 25 via the discharge valve mechanism is sent out from the high pressure chamber 82 to the refrigeration circuit via the discharge passage. In the meantime, in this swash plate compressor, the mist-like lubricating oil contained in the refrigerant gas causes the bore 5
Lubrication is performed on the lubrication necessary parts such as the sliding surface between the a and 5b and the double-headed piston 6, the sliding surface between the swash plate 12 and the shoe 13, and the engagement surface between the shoe 13 and the double-headed piston 6. ..

If the air conditioner is stopped for a long time,
The liquid refrigerant and the lubricating oil are stored in the compressor due to the temperature difference between the respective portions of the refrigeration circuit while stopped. Then, when the swash plate type compressor is restarted by high speed rotation, the respective bores 5a, 5b perform compression while the liquid refrigerant and the lubricating oil are stored in the compressor. At the time of liquid compression in each of the bores 5a and 5b, since the liquid lubricating oil is an incompressible fluid, the pressure inside the bore rises. The bore pressure is introduced from the bores 5a and 5b into the bore pressure sensing chamber 80 through the through holes 33 and 34 and the pressure sensing hole 35. Therefore, the spool 41
Moves over the spring 44 and slides toward the low pressure chamber 81, and the ball valve 43 opens the bypass passage 83 via the rod 42.
This responsiveness is superior to the conventional sensing of a decrease in suction pressure. The bores 5a and 5b are double-headed pistons 6
A compression stroke or a suction stroke is performed on both head sides of the swash plate 12
Each pair of bores 5a, 5b also performs a compression stroke or a suction stroke by the rotation of the ball. However, check valves 31, 32 are interposed between the bores 5a, 5b and the ball valve 43, respectively.
When the seats 1a and 32a are seated, the bore pressure does not flow backward from the bores 5a and 5b in the suction stroke to the bores 5a and 5b in the suction stroke. Therefore, at this time, the lubricating oil is supplied from the high pressure chamber 82 to the suction chamber 81 through the bypass passage 83 without passing through the refrigeration circuit. Therefore, in this swash plate type compressor, seizure of the lubrication necessary portion immediately after starting is effectively prevented with almost no unlubricated state.

It should be noted that, after a few seconds have passed, if the liquid compression in the bores 5a, 5b disappears and the pressure inside the bores drops, the spool 41
Is returned to the pressure sensing chamber 80 side in the bore by the spring 44, the ball valve 43 is seated, and the bypass passage 83 is closed. As a result, the refrigerant gas sucked into the bores 5a, 5b and subjected to the compression action as usual is circulated from the high pressure chamber 82 to the refrigeration circuit without flowing from the high pressure chamber 82 to the low pressure chamber 81.

[0016]

As described above in detail, in the reciprocating compressor for vehicle air conditioning of the present invention, the bypass passage for bypassing the compressed refrigerant gas from the discharge side to the suction side and the pressure in the bore immediately after the start-up are provided. Since it is provided with the initial lock prevention valve that opens the bypass passage due to a high rise, it is possible to effectively prevent seizure of the swash plate, the shoe, and other necessary parts immediately after startup with excellent responsiveness.

Therefore, in this reciprocating compressor for air conditioning of the vehicle, the durability can be improved by reliably preventing the seizure.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a swash plate compressor according to an embodiment.

FIG. 2 is a partial cross-sectional plan view of the swash plate compressor of the embodiment.

FIG. 3 is a schematic diagram of a refrigeration circuit equipped with a swash plate compressor according to an embodiment. 81 ... Low pressure chamber (suction side) 82 ... High pressure chamber (discharge side) 83 ... Bypass passage 5a, 5b ... Bore 31, 32 ... Check valve 43 ... Ball valve (initial lock prevention valve)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hayato Ikeda 2-chome Toyota-cho, Kariya city, Aichi Prefecture Toyota Industries Corporation

Claims (1)

Claim: What is claimed is: 1. A bypass passage communicating between a discharge side and a suction side for bypassing compressed refrigerant gas, and a pressure inside a bore introduced from each bore via a check valve. A reciprocating compressor for vehicle air conditioning, comprising: an initial lock prevention valve that opens the bypass passage due to a rise in pressure in the bore immediately after startup.