JPS62298671A - Capacity control mechanism in variable capacity compressor - Google Patents

Abstract

PURPOSE:To aim at the promotion of suitability to capacity control at both summer and winter seasons, by installing a high-pressure valve in a discharge pressure passage to be interconnected to the inside of a crankcase from the discharge side of a cylinder and a pressure relief valve in a pressure escape passage leading to the suction side of the cylinder from the crankcase side by side, respectively. CONSTITUTION:A compressor A to be driven by an engine via the belt 7 rolled on a pulley 6 is provided with a piston 4 being reciprocated by rotation at the tilted state of a wobble plate 8. And, a tilt angle of this wobble plate 8 is automatically adjusted according to a pressure differential between pressure inside a crankcase and suction pressure inside each cylinder 3 whereby capacity of the compressor is controlled. In this case, a high-pressure valve B is installed in discharge pressure feed passages d'' and d''' to be interconnected to the inside of a crankcase 1 from the discharge side of the cylinder 3 side by side, and this valve B is controlled by the suction pressure of the cylinder 3. Likewise, a medium pressure relief valve C is installed in pressure escape passages c and c' leading to the suction side from the inside of the crankcase 1 side by side.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a capacity control mechanism in a variable capacity compressor.

[Conventional technology]

In Kartara, the compressor is installed in conjunction with the car engine, so the rotational speed of the compressor varies widely between when the car is driving on a city road and when driving on a highway. Sometimes, the suction amount of the compressor becomes excessive, and the low pressure decreases in the intermediate period, and the compressor is opened and closed frequently because the capacity exceeds what is necessary, and the blowing temperature becomes too low, creating a feeling of draft, which causes waste. There are disadvantages such as the use of power.

As a countermeasure to this problem, as shown in Japanese Patent Publication No. 58-158382, a variable-capacity compressor with a variable-angle wobble temporary type detects the suction pressure and controls the pressure inside the compressor to vary the capacity. It is intended to maintain pressure (temperature).

By the way, in the above-mentioned known technology, since a high-pressure valve and an intermediate-pressure valve are provided and both are connected by a single shaft so as to interlock, it is impossible to close both valves. The lift ffi of the intermediate pressure valve is increased to a certain extent when there is a lot of vibratory force.As a result, if the vibratory force is large, the pressure Pc in the crankcase will rise and the unloader will work even if the pressure Ps on the suction side of the compressor is high. However, for this reason, when it is desired to increase the pressure Pc in the crankcase in winter, the intermediate pressure valve does not close to close even if the high pressure valve opens. .

[Problem that the invention seeks to solve]

The present invention has been made with attention to the above-mentioned points, and by separating the high-pressure valve and the intermediate-pressure valve in the known technology and making it possible to adjust them so that they operate independently, it is possible to solve the problem during high loads in summer. This enables continuous operation of the variable capacity compressor depending on the low load in winter.

[Means for solving problems]

In order to achieve the above object, in the present invention, a high pressure valve installed in a discharge pressure supply passage communicating from the discharge side of the piston cylinder into the crankcase is controlled by the suction pressure of the piston cylinder, and the high pressure valve is controlled by the suction pressure of the piston cylinder. A configuration was adopted in which a medium-pressure pressure relief valve was installed in the pressure relief passage leading from the inside to the suction side of the piston cylinder.

That is, as shown in FIG. 4, when the suction pressure Ps of the compressor decreases at low load, the intermediate pressure valve starts to close slowly in the known technique, so that the crankcase pressure Ps decreases.
c is difficult to rise. Therefore, suction pressure Ps=1.8K
g/cfll (Pc = 2.8 Kg/cfll), or the unloader will not work.

〔Example〕

In FIG. 1, A is a compressor, and B and C are high-pressure capacity control and medium-pressure pressure relief valves fixed in mounting recesses H and H' on one side of the compressor A.

In the compressor A, there are a plurality of cylindrical cylinders 3°3' in the head portion 2 that is continuous with the crankcase 1.
Each cylinder 3, 3', . . . has a piston 4 slidably provided therein. A drive shaft 5 is rotatably provided from the crankcase 1 to the head portion 2, and the drive shaft 5 is driven by an engine (not shown) via a belt 7 via a pulley 6 provided at the outer end. The drive shaft 5 is provided with a variable angle wobble plate 8 as is known in the art, and the wobble plate 8 and the piston 4 are connected to a piston rod 9 having spherical connecting ends 9a, 9a at both ends via an annular groove 8a and a socket 4a.
When the wobble plate 8 is rotated in an inclined state by the drive shaft 5, the piston rod 9 to the piston 4 reciprocate, and the pressure Pc inside the crankcase 1 and the inside of the cylinders 3, 3... The mounting angle of the wobble plate 8 is automatically adjusted according to the differential pressure between the suction pressure Ps and the angle of the wobble plate 8, and the stroke amount of the piston 4 changes as the angle of the wobble plate 8 changes.

Each cylinder 3, 3'... is provided with a suction port S and a discharge port, each suction port S communicates with each other through an internal passage S, and each discharge port communicates with each other through an internal passage d. are doing. One cylinder 3 has a passage S'.

An evaporator 10 and a condenser 11 constituting a refrigeration cycle are connected via d'.

The suction port S is provided with a valve body 12 that opens during the suction stroke of the piston 4 (and closes during the discharge stroke), and the discharge port is provided with a valve body 13 that opens during the discharge stroke of the piston 4 and closes during the suction stroke.

In the capacity adjustment valve B, a pressure responsive part M is provided on one side of the main body 14.
is provided. The pressure-responsive part M includes an upper cover 17 with a diaphragm 16 sandwiched between a lower cover 15 fixed to the main body 14, a spring box 18 fixed to the upper cover 17, and an adjustment mechanism screwed into the spring box 18. An adjustment spring 22 is provided between the screw 19 and a spring receiver 21 that comes into contact with the upper stopper 20 of the diaphragm 16.

A stop 24 of an interlocking ring 23 is in contact with the other side of the diaphragm 16. The interlocking ring 23 extends through the sliding hole 14a of the main body 14, and a part of the interlocking ring 23 and the stopper 24 are located in the pressure receiving chamber R1, and the suction pressure Ps is placed in the pressure receiving chamber R1. A suction pressure introduction port 14 communicating with the passage S'' for introducing
b is formed.

The interlocking ring 23 extending through the sliding hole 14a reaches the valve chamber R2, and a ball valve element 25 fixed to its tip opens and closes the valve seat (2). And a spring receiver 26 that comes into contact with the ball valve body 25
An adjustment spring 28 facing the adjustment spring 22 is provided between the adjustment screw 27 and the adjustment screw 27 screwed onto the main body 14.

Note that 29 is a seal ring.

A discharge pressure introduction port 14C communicating with the discharge pressure passage d'' is provided on the primary side of the valve chamber R2, and a discharge pressure supply port 14D communicating with the discharge pressure supply passage d'' to the crankcase 1 is formed on the secondary side. be done.

In the pressure relief valve C, a responsive portion M' is provided on one side of the main body 30. The pressure responsive part M' is provided with an upper lid 33 with a diaphragm 32 held between a lower lid 31 fixed to a main body 30, a spring box 34 fixed to the upper lid 33, and screwed into the spring box 34. An adjustment spring 38 is provided between the adjustment screw 35 and a spring receiver 37 that comes into contact with the upper stopper 36 of the diaphragm 32.

A valve body 39 is in contact with the other side of the diaphragm 32, and a spring 40 facing the adjustment spring 38 is provided between the valve body 39 and the main body 30.

The valve body 39 and the spring 40 are located in the valve chamber R3, and the valve body 3
9 opens and closes the valve seat V'.

The primary side of the valve chamber R3 is provided with an intermediate pressure introduction hole 30a that communicates with the relief passage C of the intermediate pressure PC in the crankcase 1, and the secondary side is provided with a relief passage C' for the suction side of the compressor.
An intermediate pressure outlet 30b is provided which communicates with the above.

In the above configuration, the suction pressure Ps is introduced into the pressure receiving chamber R1 from the suction pressure introduction port 14b via the passage S'' and opposes the adjustment spring 22 via the diaphragm 16. diaphragm 16
operates to move the interlocking frame 23 to the left in the drawing, and the valve body 25 opens the valve seat (■) to introduce the discharge pressure Pd into the crankcase 1, thereby reducing the pressure P in the crankcase 1.
The stroke of the piston 4 is made smaller by raising C and raising the wobble plate 8.

When the suction pressure Ps increases, it operates in reverse and cuts off the supply of discharge pressure into the crankcase 1.

The pressure relief valve C is adjusted to release pressure to the suction side in accordance with the amount of discharge pressure Pd that blows through the seal ring of the piston 4 in the compressor.

〔Example〕

During high load in the summer (Figure 2), when the indoor temperature is high near the compressor discharge pressure Pd = 15 Kg/cal, the evaporator pressure, that is, the compressor suction pressure Ps, should be kept as low as possible to quickly lower the room temperature. and unloading is started when the suction pressure P S = 1.6 Kg/cut is reached, and it is ensured that the pressure does not fall below that. Discharge pressure P
d is 15Kg/c! When it is around ll, the unloader operating differential pressure ΔPsc (Pc-Ps) is about 1.4 Kg/cj.

At P s = 2.9 Kg/cj, the high pressure valve is closed for maximum performance and the suction pressure p s = 1.9
When it reaches Kg/- position, the valve body 25 starts to open and the suction pressure Ps=1.6Kg/a11, and the crankcase pressure Pc
Adjust so that = 3 Kg/cd.

During low load (during dehumidification operation) in winter (Fig. 3), the compressor discharge pressure P d = 4 KglctA When the indoor temperature is low, the compressor suction pressure Ps
If the pressure drops below 2Kg/c4, the evaporator will begin to freeze, so in order to prevent the suction pressure Ps from dropping below 2Kg/c4, the suction pressure Ps=2Kg/c4 is used for unloading.
I will work when I get to sA. Discharge pressure Pd=4Kglcs
When it is near A, the unloading operation differential pressure ΔPsC is LKg/
It is ad position.

〔Effect of the invention〕

As described above, the present invention controls the high pressure valve installed in the discharge pressure supply passage communicating from the discharge side of the piston cylinder into the crankcase by the suction pressure of the piston cylinder, and Since a pressure relief valve is provided in the pressure relief passage leading to the suction side, the high pressure valve and intermediate pressure relief valve can be adjusted individually and operated independently, so that they can be easily operated during high loads in the negative phase. The variable capacity compressor can be operated appropriately depending on the low load in winter.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of an embodiment of the present invention, Fig. 2 is a graph showing operating conditions in summer, Fig. 3 is a graph showing operating conditions in winter, and Fig. 4 is a graph showing compressor suction at low load. A graph showing the relationship between the pressure PS and the unloader, and FIG. 5 is a graph showing the relationship between the suction pressure of the compressor and the valve opening degree. A...Compressor, B...High pressure valve, C...Pressure relief valve, d", d""...Discharge pressure supply passage, c,
c'...Pressure relief passage. Patent applicant: Saginomiya Seisakusho Co., Ltd. Figure 4

Claims (1)

[Claims] A high pressure valve installed in the discharge pressure supply passage communicating from the discharge side of the piston cylinder to the inside of the crankcase is controlled by the suction pressure of the piston cylinder, and a high pressure valve installed in the pressure relief passage leading from the inside of the crankcase to the suction side of the piston cylinder is controlled by the suction pressure of the piston cylinder. A capacity control mechanism in a variable capacity compressor, characterized by comprising a pressure relief valve.