JPS62282182A - Capacity control mechanism for variable capacity compressor - Google Patents

Abstract

PURPOSE:To operate a variable capacity compressor smoothly by controlling a valve for supplying a delivery pressure to a crankcase by means of an intake pressure and relieving the pressure in the crankcase through a fixed orifice to the intake side. CONSTITUTION:In this compressor, an intake pressure Ps is led through a path S'' and an intake pressure lead-in port 14b into a pressure receiving chamber R1 so as to resist against an adjusting spring 22 through a diaphragm 16. When the intake pressure Ps lowers, the diaphragm 16 functions to push down an interlocking rod 23 then a valve body 25 opens a valve seat V so as to lead the delivery pressure Pb into a crankcase 1. Consequently, the pressure Pc in the crankcase 1 increases and a wobble board 8 stands thereby the stroke of a piston 4 is shortened. Since the interior of the crankcase 1 is communicated through a fixed orifice C with an intake port S, the fluctuation of the differential pressure between the inside and the outside of the crankcase is reduced thereby the operation is smoothed.

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 there is a wide variation in the rotation speed of the compressor when the car is driving on a city road and when driving on a highway. The suction volume becomes excessive and the low-pressure pressure decreases, especially in the intermediate period, and the compressor opens and closes frequently because the capacity exceeds what is necessary, and the blowout temperature becomes too low, creating a feeling of draft and wasting power. There are disadvantages such as using

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, the above-mentioned known technology has the drawbacks that since it incorporates both a high-pressure valve and an intermediate-pressure valve, the external dimensions and weight increase, and the number of machining operations for the compressor increases, resulting in an increase in manufacturing man-hours. On the other hand, the high-pressure valve and intermediate-pressure valve are linked, and the difference in pressure between the inside and outside of the crankcase changes rapidly, which tends to cause a hunting phenomenon in which the suction pressure rises and falls. As the load on the piston changes suddenly, the compressor no longer rotates smoothly, which causes vibrations in the compressor itself.

[Problem that the invention seeks to solve]

The present invention has been made with attention to the above points, and the intermediate pressure valve is separated from the high pressure valve to form a fixed orifice, thereby slowing down the change in differential pressure between the inside and outside of the crankcase, thereby improving the smoothness of compressor operation. The structure of this type of compressor is simplified.

[Means for solving problems]

In order to achieve the above object, in the present invention, a valve body installed in a discharge pressure supply passage connected 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 the valve body is controlled by the suction pressure of the piston cylinder. A configuration is adopted in which a pressure relief passage is provided from inside the case to the suction side of the piston cylinder via a fixed orifice.

〔Example〕

In FIG. 1, A is a compressor, and B is a high-pressure capacity control valve fixed in a mounting recess H on one side of the compressor A.

In the compressor A, a plurality of cylinders 3゜3'...
A piston 4 is slidably provided in each cylinder 3, 3', . . . . crank case 1
A drive shaft 5 is rotatably provided from the head portion 2 to the head portion 2, and the drive shaft 5 is driven by an engine (not shown) via a belt 7 via a boot IJ6 provided at the outer end. Drive shaft 5
is provided with a variable angle wobble plate 8 as is well known, and the wobble plate 8 and the piston 4 are connected to an annular groove 8a and a socket 4a.
The wobble plate 8 is rotated in an inclined state by the drive shaft 5, so that the piston rod 9 to the piston 4 reciprocate, and the crankcase 1 internal pressure P
The mounting angle of the wobble plate 8 is automatically adjusted according to the differential pressure between the suction pressure Ps in the cylinders 3, 3', etc., and the stroke amount of the piston 4 is adjusted by changing the angle of the wobble plate 8. changes.

Each cylinder 3, 3'... is provided with a suction port S and a discharge port. It's communicating. One cylinder 3 has a passage s'.

An evaporator 10 and a condenser 11 constituting a refrigeration cycle are connected via d'. A valve body 12 is provided at the suction port S, which opens during the suction stroke of the piston 4 and closes during the discharge stroke.
A valve body 13 is provided at the discharge port, which 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 lid 17 with a diaphragm 16 held between a lower lid 15 secured to the main body 14, a spring box 18 secured to the upper lid 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 rod 23 is in contact with the other side of the diaphragm 16. The interlocking rod 23 extends through the sliding hole 14a of the main body 14, and a part of the interlocking rod 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 that communicates with the passage S'' that introduces
b is formed.

Sliding hole 14. The interlocking rod 23 extending through the valve chamber R2
The ball valve body 25 fixed to the tip reaches the valve seat ■
Open and close. And the spring receiver 2 that comes into contact with the pole valve body 25
An adjustment spring 28 opposing 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 inlet 14C communicating with the discharge pressure supply passage d'' is provided on the primary side of the valve chamber R2, and a discharge pressure supply port 14C communicating with the discharge pressure supply passage d'' for the crankcase 1 is provided on the secondary side. is formed.

A relief passage C for the crankcase pressure Pc is provided from the crankcase 1 to the suction port S via a fixed orifice C, and the diameter of the fixed orifice C corresponds to the amount of discharge pressure PdO that blows through the seal ring of the piston 4. Designed accordingly.

In the above configuration, the suction pressure Ps is introduced into the pressure receiving chamber R8 from the suction pressure introduction port 14b via the passage S", and opposes the adjustment spring 22 via the diaphragm 16. When the suction pressure Ps becomes low, the diaphragm 16
operates to push down the interlocking rod 23 in FIG. By raising it upright, the stroke of the piston 4 is made smaller.

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

Figure 2 shows high-pressure valves in the conventional example (a) and the present invention (b).
This figure shows the relationship between the refrigerant flow rate and the change in the suction pressure Ps in the intermediate pressure valve combination and the high pressure valve-fixed throttle combination, and in the present invention, the change in refrigerant flow rate is gradual, that is, the pressure fluctuation occurs gradually. It shows.

〔Effect of the invention〕

As described above, the present invention controls the valve body provided 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 controls the valve body from the inside of the crankcase through the fixed orifice. Since a pressure relief passage is provided leading to the suction side of the piston cylinder, it is possible to ensure smooth operation of the compressor by slowing down the change in differential pressure between the inside and outside of the crankcase when the suction pressure fluctuates. Furthermore, the structure of the compressor can be simplified.

[Brief explanation of drawings]

Figure 1 is an explanatory diagram of one embodiment of the present invention, and Figure 2 (
(a) and (b) are graphs showing the relationship between suction pressure fluctuation and refrigerant flow rate in the conventional example (a) and the present invention (b). A...Compressor, B...Capacity control valve, 1...
Crankcase, d" d ///...Discharge pressure supply passage, 25...Valve body, C...Fixed orifice,
C...Pressure relief passage.

Claims (1)

[Claims] A valve body installed in a 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 the valve body is connected to the suction side of the piston cylinder from inside the crankcase through a fixed orifice. A capacity control mechanism for a variable capacity compressor, characterized in that it is provided with a pressure relief passageway extending all the way to the top.