JP2559645Y2 - Swash plate compressor - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a swash plate type compressor in which lubricating oil is prevented from being taken out by changing the blow-by amount characteristic of a piston ring for some pistons.

[0002]

2. Description of the Related Art For example, as a compressor used in an air conditioner for a vehicle, there is a variable displacement swash plate type compressor disclosed in Japanese Utility Model Laid-Open No. 62-76289.

In such a variable displacement swash plate type compressor, the volume of the compression chamber in the cylinder is changed in accordance with the suction pressure of the refrigerant returning to the compressor, the amount of refrigerant discharged from the compressor is adjusted, and the suction pressure of the compressor is made constant. Things.

By making the suction pressure constant in this way, the refrigerant pressure at the outlet of the evaporator (ie, the refrigerant pressure
The evaporation pressure of the refrigerant in the evaporator) becomes constant to some extent, and so-called low-load evaporator freezing can be avoided. Further, since the compressor produces a discharge amount corresponding to the heat load, ON / OFF of the compressor by the conventional magnetic clutch can be reduced as much as possible, and ON / O of the compressor can be reduced.
The sudden change in the temperature of the blown air and the sudden change in the torque of the engine rotation caused by the FF are eliminated, so that the driving comfort can be improved.

[0005]

A thrust bearing and a radial bearing, which are sliding surfaces between a drive swash plate and a socket plate, a radial bearing and a socket, which are sliding surfaces between a drive shaft and a compressor casing, are provided inside the compressor. Various sliding members such as shoes, which are sliding surfaces between the plate and the guide pins, are provided, and it is necessary to supply lubricating oil to these sliding members to prevent seizure while the compressor is operating. is there. Therefore, by lubricating the lubricating oil in the oil reservoir formed at the bottom of the compressor casing by the rotation of the drive swash plate, or by guiding the lubricating oil contained in the refrigerant circulating in the cooling cycle to the sliding member. Ensures a smooth working condition. In particular, since the refrigerant introduced into the compression chamber flows out to some extent as blow-by gas from between the piston and the cylinder into the crank chamber, the lubricating oil contained in the refrigerant is used to lubricate the sliding member described above. It was the actual situation that we expected supply.

However, the fact that the refrigerant containing the lubricating oil flows into the crank chamber from between the piston and the cylinder means that the refrigerant flows out of the crank chamber into the compression chamber. If the balance is lost, the lubricating oil in the oil reservoir will decrease, and this will support the durability of the compressor.

[0007] The present invention has been made in view of such problems of the prior art, and has as its object to increase the durability of a compressor by suppressing the carry-out of lubricating oil inside the compressor.

[0008]

In order to achieve the above object, according to the present invention, a drive shaft (11) is rotatably provided in a closed casing (17) having an oil reservoir (66) below. 17) Crank chamber (12) formed inside
A drive swash plate (13) that rotates inside is mounted at an angle to the drive shaft (11), and a plurality of pistons (23) reciprocate in a plurality of cylinders (25) formed in the casing (17). ) Is connected to the driving swash plate (13),
The refrigerant is sucked through a suction port (29) into a compression chamber formed by the front surface of the piston (23) and the inner wall of the cylinder (25).
In the swash plate compressor discharged from 3), the blow-by amount of the pistons (23d, 23e) close to the oil reservoir (66) among the pistons (23) is reduced by the pistons (23a, 23b, 23c) other than the pistons. A swash plate type compressor characterized in that the blow-by amount is smaller than the blow-by amount.

At this time, the piston ring (70) of the piston (23d, 23e) close to the oil reservoir (66) is used as an endless ring (70b), and the piston (23) other than the piston (23) is used.
a, 23b, 23c) is preferably an end ring (70a).

[0010]

In general, the refrigerant in the compression chamber of the piston in the compression stroke passes through a slight gap existing between the piston (23) and the cylinder (25) and passes through the crank chamber (1).
2), the lubricating oil contained in the refrigerant is supplied to the sliding member in the crank chamber (12). Conversely, for the piston in the suction stroke, the refrigerant in the crank chamber (12) tries to flow into the compression chamber through the gap, and lubricating oil contained in the refrigerant in the crank chamber,
Alternatively, the lubricating oil stored in the oil sump (66) is about to be taken out of the crank chamber. However, the compressor according to the present embodiment includes the lubricating oil stored in the oil sump (66), that is, the piston (23d,
Since the blow-by amount of 23e) is set to be small, the other pistons (23a, 23b, 23c) are taken out of the crankcase while being contained in the refrigerant, but the lubricating oil to the outside of the crankcase as a whole compressor Can be suppressed. In other words, if the blow-by amount of the piston is reduced uniformly, the amount of lubricating oil taken out of the crank chamber can be suppressed, but the amount of lubricating oil flowing from the compression chamber into the crank chamber also decreases, and the sliding inside the crank chamber is reduced. Supply of lubricating oil to parts can no longer be expected,
In supplying lubricating oil by the blow-by gas of the piston, the residual lubricating oil amount of the entire compressor is determined by the balance of the blow-by amount of each piston. Therefore, in the present invention, the blow-by amount of the piston at the portion where the lubricating oil concentration is high is set smaller than that of the other pistons.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing a swash plate type compressor according to an embodiment of the present invention, FIG. 2 is an enlarged sectional view showing a piston according to the embodiment, FIG. 3 is a perspective view showing a piston ring according to the embodiment. 4 is a perspective view showing a piston ring according to the embodiment, FIG. 5 is a perspective view showing a piston according to another embodiment of the present invention, and FIG. 6 is a sectional view taken along line AA of FIG.

Variable capacity swash plate type compressor 3 of this embodiment
1, has a drive shaft 11 that is driven to rotate by an engine via a belt (not shown), a pulley 2, and a magnet clutch 2a. This drive shaft 1
1 is rotatably supported at the opening of the casing 17 of the crank chamber 12 via the drive shaft thrust bearing 67 and the drive shaft radial bearings 68a, 68b. Is provided with a seal member 65 for sealing the refrigerant and lubricating oil in the compressor in the casing 17. A drive rod 11 a is provided on the drive shaft 11 so as to project in a direction perpendicular to the drive shaft 11, and rotates with the drive shaft 11 in the crank chamber 12.

A drive swash plate 13 is connected to the drive rod 11a so that the drive swash plate 13 can tilt and swing with respect to the drive shaft 11 about a pin 11b as a fulcrum.
The light is transmitted to the driving swash plate 13 via the pin 1a and the pin 11b. A non-rotating socket plate 16 is slidably attached to the drive swash plate 13 via a thrust bearing 14 and a radial bearing 15. Socket plate 16
Has a shoe 19 slidably connected to a guide pin 18 fixed to a casing 17 of the crank chamber 12. The shoe 19 prevents rotation, while allowing reciprocation in the axial direction. I have. Further, a plurality of piston rods 22 are attached to the socket plate 16 via a spherical bearing 22a at equal intervals in the circumferential direction. A piston 23 is connected to the other end of the piston rod 22 via a spherical bearing 22b. ing. Then, with the rotation of the drive swash plate 13, the socket plate 16 reciprocates in the axial direction by performing a so-called razor-like operation, whereby the piston 23 reciprocates via the piston rod 22. ing. Note that the front side portion of the piston 23 of the cylinder 25 in which the piston 23 is inserted serves as a compression chamber, and the rear side portion communicates with the crank chamber 12.

The cylinder head 30 is provided with a suction port 29 and a discharge port 33. The return port refrigerant from the evaporator flows into the suction port 29, and the refrigerant returns to the suction port 27 opened in the valve plate 20. It flows into a compression chamber formed in the cylinder bore 26 against the closing resilience of the suction valve 34 to be closed. Also,
This refrigerant is guided to the suction side pressure chamber 32 through a communication passage 32a formed in the cylinder head 30 and communicating with the suction port 29.

On the other hand, the discharge port 33 is a portion where the compressed refrigerant flows out, and communicates with a pipe (neither is shown) for sending the refrigerant discharged from the discharge port 28 formed in the valve plate 20 to the condenser. , And communication path 3
It communicates with the discharge side pressure chamber 35 via 5a.

A control valve C, which operates according to the pressure of the refrigerant returning to the suction port 29 of the cylinder 25, is provided between the suction side pressure chamber 32 and the discharge side pressure chamber 35.
v is provided. This control valve Cv is
If the pressure of the returning refrigerant is low, the first valve port 40 is closed and the second valve port 47 is opened. If the pressure is high, the first valve port 40 is opened and the second valve port 47 is closed. The first control valve 36 in the lower part,
A second control valve 39 is provided at the top. First control valve 36
Are bellows 37 which expand and contract according to the internal pressure of the suction side pressure chamber 32, and springs 38 provided in the bellows 37.
The opening degree of the first valve port 40 is adjusted by the balance of the force with the above. The first control valve 36 has an operating rod 4
The operation rod 46 is used to control the second control valve 3.
9 is opened and closed, that is, both control valves 36 and 39 operate in conjunction with each other. When the first control valve 36 increases the opening of the first valve port 40 as described above, ,
The second control valve 39 operates to reduce the opening of the second valve port 47.

Variable capacity swash plate type compressor 3 of this embodiment
6 are provided for convenience as shown in FIG. 6 (in FIG. 6, the piston 23
a) only), the oil sump 66 of the casing 17
The configuration of the piston rings 70 attached to the lower two pistons 23d, 23e where the is located and the remaining three pistons 23a, 23b, 23c respectively is changed. That is, each of the piston rings 70 is made of a relatively hard synthetic resin having a low frictional resistance, for example, trifluoroethylene resin (Teflon resin) or the like. However, the upper three pistons 23a, 23b,
In the case of 23c, the piston ring 70 is constituted by an end ring 70a as shown in FIG. 3, while in the lower two pistons 23d and 23e, the piston ring 70 is constituted by an endless ring 70b as shown in FIG. doing. As described above, in the pistons 23d and 23e having the piston rings constituted by the end rings 70a, the refrigerant in the compression chamber tends to flow into the crank chamber 12 as blow-by gas from the gaps at both ends of the piston ring 70a. On the other hand, the pistons 23a, 23b and 23c having the piston ring constituted by the endless ring 70b
Is more excellent in the sealing performance between the piston 23 and the cylinder 25 than the piston in which is inserted, so that the blow-by amount is reduced. Therefore, the amount of refrigerant leaking from the two pistons 23d and 23e adjacent to the oil reservoir 66 of the casing 17 is equal to the amount of the pistons 23a, 23b and 23 other than these pistons.
Since the amount of refrigerant leaking from c is smaller than that, the carry-out of lubricating oil in a portion having a high lubricating oil concentration can be suppressed.

The present invention is not limited to the above-described embodiment, but can be variously modified. For example, when it is desired to slightly increase the blow-by amount as a whole compressor, the upper three pistons 23a,
The piston rings of 23b and 23c are termed end rings 70a, while the piston rings of the lower two pistons 23d and 23e are constituted by two endless rings 70b and one end ring 70a as shown in FIG. good.

Next, the operation will be described. First, when the heat load in the cooling cycle is small, the pressure of the return-refrigerant returns at a low pressure without obtaining a sufficient superheat amount, so that the pressure in the suction-side pressure chamber 32 (hereinafter, suction pressure Ps) decreases. The bellows 37 extends upward, opens the second valve port 47 widely, and discharges a part of the compressed refrigerant (hereinafter, discharge pressure Pd) compressed by the piston 23 in the compression process from the discharge port 28 through the second valve port 47. Passage 62 → Passage 63 → Passage 4
8 → Central hole 44 → Central chamber 12 through central passage 45
To increase the internal pressure of the crank chamber 12 (hereinafter referred to as crank chamber pressure Pc). By this action,
The inclination angle of the socket plate 16 is controlled by the pressure balance before and after applied to the plurality of pistons 23. That is, the pressure P in the crank chamber 12
When c becomes slightly larger than the pressure on the suction side, the resultant force of the forces applied to the back surfaces of the plurality of pistons 23 acts on the socket plate 16 as a moment centered on the pin 11b, reducing the inclination angle of the socket plate 16. Act as if to let. For this reason, the piston 23 in the suction process cannot retreat so as to have a sufficiently large stroke, and can take only a small compression stroke when the next compression process is started. The amount of the discharged refrigerant is small, the flow rate of the refrigerant circulating in the cooling cycle is reduced, and the amount of the refrigerant is appropriate for a low heat load. Due to this decrease in the amount of refrigerant, the suction pressure Ps of the compressor 3 gradually increases, and as a result, the suction pressure Ps is kept constant.

On the other hand, when the heat load in the cooling cycle is large, the suction pressure Ps increases, the bellows 37 contracts, the first control valve 36 moves downward, and the opening of the first valve port 40 increases. Then, the opening of the second valve port 47 is reduced. Therefore, the high-pressure discharge pressure Pd is not introduced into the crank chamber 12, and when the suction pressure Ps is smaller than the pressure Pc in the crank chamber 12, the refrigerant in the crank chamber 12 is discharged from the cylinder passage 61 →
It flows through the passage 41 → the first valve port 40 → the bellows chamber 64, whereby the crank chamber pressure Pc and the suction pressure Ps become substantially equal. Therefore, the socket plate 16 and the drive inclined plate 13 are inclined to the maximum with respect to the drive shaft 11 by the action of the above-mentioned moment, and the piston 23
Reciprocating stroke becomes longer. Therefore, when compression is performed in this state, the discharged refrigerant amount increases, the refrigerant flow rate circulating in the cooling cycle increases, the refrigerant flow rate becomes appropriate in accordance with the high heat load, and the suction pressure Ps of the compressor 3 gradually decreases. As a result, a constant suction pressure Ps is maintained.

At this time, the refrigerant in the compression chamber of the piston in the compression stroke tries to flow into the crank chamber 12 through a slight gap existing between the piston 23 and the cylinder 25, and is contained in the refrigerant. Lubricating oil is in crankcase 1
2 are supplied to the sliding members 14, 15, 67, 68a, 68b. Conversely, for the piston in the suction stroke, the refrigerant in the crank chamber 12 tries to flow into the compression chamber through the gap and is stored in the lubricating oil contained in the refrigerant or the oil sump 66 in the crank chamber. Lubricating oil is taken out of the crankcase. However, the compressor of the present embodiment uses the lubricating oil stored in the oil sump 66, that is, the pistons 23d, 2
Since the blow-by amount 3e is set to be small, it is taken out of the crankcase while being contained in the refrigerant from the upper three pistons 23a, 23b, 23c shown in FIG. Of lubricating oil can be suppressed. In other words, if the blow-by amount of the piston 23 is uniformly reduced, the amount of lubricating oil taken out of the crank chamber can be suppressed. Supply of lubricating oil to the moving member cannot be expected. As described above, in the supply of the lubricating oil by the blow-by gas of the piston, the residual lubricating oil amount of the entire compressor is determined by the balance of the blow-by amount of each piston. The blow-by amount of the piston in is set smaller than the other pistons.

[0022]

As described above, according to the present invention, the drive shaft is rotatably provided in a closed casing having an oil reservoir below, and the drive swash plate rotating in the crank chamber formed in the casing is provided. A plurality of pistons reciprocating in a plurality of cylinders formed in the casing and attached to the drive shaft at an angle are connected to the drive swash plate, and a compression formed by the front surface of the piston and the cylinder inner wall. In the swash plate type compressor, which sucks the refrigerant into the chamber through the suction port and compresses the refrigerant and discharges the refrigerant from the discharge port, the blow-by amount of the piston close to the oil reservoir among the pistons is reduced by the amount of the piston other than the piston. Since the amount is smaller than the blow-by amount, the amount of lubricating oil taken out of the compressor through the gap between the piston and cylinder near the oil sump is suppressed. It can, overall it is possible to ensure the amount of lubricating oil is stored within the compressor. Therefore, the durability of the compressor is increased, and the cooling capacity of the cooling cycle is improved.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a swash plate type compressor according to an embodiment of the present invention.

FIG. 2 is an enlarged sectional view showing a piston according to the embodiment.

FIG. 3 is a perspective view showing a piston ring according to the embodiment.

FIG. 4 is a perspective view showing a piston ring according to the embodiment.

FIG. 5 is a perspective view showing a piston according to another embodiment of the present invention.

FIG. 6 is a sectional view taken along the line AA of FIG. 1;

[Explanation of symbols]

11 drive shaft, 12 crankcase,
13: Drive swash plate, 17: Casing, 23: Piston, 25: Cylinder, 27: Suction port, 28: Discharge port, 66: Oil reservoir.

Claims (2)

(57) [Scope of request for utility model registration] A drive shaft (11) is rotatably provided in a closed casing (17) having an oil reservoir (66) below, and a crank chamber (12) formed in said casing (17).
A drive swash plate (13) that rotates inside is mounted at an angle to the drive shaft (11), and a plurality of pistons (23) reciprocate in a plurality of cylinders (25) formed in the casing (17). ) Is connected to the driving swash plate (13),
A refrigerant is sucked through a suction port (27) into a compression chamber formed by a front surface of the piston (23) and an inner wall of the cylinder (25), and the refrigerant is compressed to a discharge port (2).
In the swash plate type compressor discharged from 8), the blow-by amount of the pistons (23d, 23e) closer to the oil reservoir (66) among the pistons (23) is reduced by the pistons (23a, 23b, 23c) other than the pistons. A swash plate type compressor characterized in that the blow-by amount is smaller than the blow-by amount. 2. A piston (23) close to the oil sump (66).
d, 23e) to the endless ring (7).
0b) and pistons (23a, 23a) other than the piston
b, 23c) with the end ring (7)
The swash plate type compressor according to claim 1, wherein 0a) is set.