JPH0325264A - Pressure sensitive type valve drive mechanism and pressure control valve of refrigeration cycle using the same mechanism - Google Patents

Abstract

PURPOSE:To miniaturize the shape of a pressure response member and reduce production cost by a method wherein an applied voltage to an electromagnetic solenoid is changed and the push pressure (valve closing force) of a return spring against the pressure response member to a valve seat is adjusted. CONSTITUTION:When an electromagnetic solenoid 21 is in no conductive state, the spring force (push load) of a return spring 20 applied on a valve body 15 through a plunger 18 becomes the maximum and therefore, the body 15 comes in contact with the valve seat 13 of an orifice 14 with pressure to close the orifice 14. As compared with this, when a voltage is applied to the solenoid 21, a magnetic attraction force against the force of the spring 20 acts on the plunger 18 and the pushing load (valve closing force) acting on the body 15 of the plunger 18 is weakened. Accordingly, when the applied voltage to the solenoid is controlled electrically, the valve opening force necessary for the body 15, that is, the aforesaid valve opening force for a pressure response member 2 acting on the body 15 can be controlled optionally. Thereby, miniaturization and the reduction of production cost can be carried out.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a pressure-sensitive valve drive mechanism and a pressure control valve for a refrigeration cycle using the same.

[Conventional technology]

BACKGROUND ART Conventionally, for example, in the field of refrigeration cycles, when a variable capacity compressor is used, a pressure control device has been used to control the outlet pressure of the evaporator and the pressure in the crank chamber of the compressor.

A conventional example of this type of pressure control device will be explained based on Fig. 4. As an example, FIG. 4 shows a system in which the pressure in the crank chamber of a variable capacity compressor used in a refrigeration cycle is arbitrarily changed by an external signal, and is disclosed in Japanese Utility Model Application Publication No. 137817/1984. In Fig. 4, 36 is the main body of the pressure control valve;
is located outside the compressor crankcase (not shown). A pressure chamber 42 containing a pressure responsive member 41 is formed inside the main body 36, and the pressure chamber 42 communicates with a compressor suction chamber (not shown) via a pressure guide 47. The pressure chamber 42 also includes a valve portion 38 that is driven by the pressure responsive member 41.
When opened, it also communicates with the crankcase via a pressure path 49. The pressure responsive member 41 is a bellows 41
A spring 40 is built in A, and the first rod 39 passes through it. The pressure-responsive member 41 performs expansion/compression expansion and contraction operations in response to the internal pressure of the pressure chamber 42 .

A second rod (valve rod) 35 with a pilot valve 34 is connected to one end of the pressure responsive member 41 via a rod 39 . The pilot valve 34 is disposed between a pressure passage 53 communicating with the discharge side of the compressor and a pressure passage 51 communicating with the crank chamber, and is urged via a spring 33 in a direction to close this passage. Further, a valve portion 38 is formed on the side of the valve rod 35 opposite to the pilot valve to open and close a pressure guide path 49 communicating with the crank chamber and a pressure guide path 47 communicating with the suction chamber of the compressor.

An electromagnetic solenoid 44 is provided at the other end 43 of the pressure responsive member 41.
A rod 46 driven by an electromagnetic force is coupled via a spring 4S, and the electromagnetic solenoid 44, rod 46, and spring 4
5 etc. serve as a setting adjustment mechanism when controlling the pressure inside the crank chamber of the compressor. Here, pilot valve 3
4 is a first valve body, and the valve portion 38 is a second valve body.

The pressure control device having such a configuration controls the pressure inside the crankcase in the following manner.

The pressure responsive member 41 installed in the pressure chamber 42
The pressure on the suction side of the compressor communicated with the compressor 2 is sensed, and the expansion and contraction operation is performed based on the differential pressure between this suction side pressure and a predetermined set pressure of the pressure responsive member 41 adjusted by the electromagnetic solenoid 44, the iron 46, etc. Accordingly, the first and second valve bodies 34 and 38 perform opening and closing operations. For example, when the pressure in the pressure chamber 42 (compressor inlet pressure) is lower than the predetermined set pressure, the pressure responsive member 41 expands, so the second valve body 38 closes, while the first valve body 34 opens. ．． Therefore, a part of the refrigerant on the discharge side of the compressor passes through the pressure guide path 53, the valve chamber 34A, and the pressure guide path 51, increasing the crankcase internal pressure. On the other hand, when the suction side pressure is higher than the predetermined general constant pressure, the pressure responsive member 41 contracts, so the second valve element 38 is opened, and the internal pressure of the crank case is reduced to approximately 49, 49, 48, Since the refrigerant is released to the suction side pressure chamber through the pressure guiding path 47 and the front second valve body 34 is closed, the supply of the discharge side refrigerant is also prevented and the pressure becomes low. In this way, the crankcase within the compressor is variably adjusted in accordance with the suction side pressure.

Further, by providing the rod 46 connected to the center of the pressure responsive member 41 so as to be stroked by the suction force of the solenoid 44, the set pressure of the pressure responsive member 41 can be changed. [Problems to be Solved by the Invention] In the above prior art, the set length of the pressure-responsive member 41 is changed by the stroke of the iron 46, which is the suction member of the solenoid 44. It was necessary to increase the maximum stroke of the member 41. By the way, the maximum amount of expansion and contraction per peak of the pressure responsive member 41 is defined by the plate thickness, outer diameter, and inner diameter of the pressure responsive member 41.

Therefore, the stroke of the rod 46, which is the suction member,
When adjusting the set length of the pressure responsive member 41, the number of threads on the pressure responsive member 41 must be increased, which increases cost and
It was at a disadvantage in terms of size.

The present invention has been made in view of the above points, and its purpose is to provide a valve drive mechanism that can adjust the set value for opening the valve element without changing the set length of the pressure responsive member. and to provide a pressure control valve using the same. [Means for solving the problem] The first problem-solving means proposes a pressure-sensitive valve drive mechanism as a basic problem-solving means to achieve the above objective. This will be explained with reference to the symbols of the embodiment in FIG. It has a pressure chamber 5 for actuating a pressure-responsive member in which the member 2 is fixed at one end, and a valve stem 12 with a valve body 15 provided at the free end of the pressure-responsive member 2. The pressure chamber 5 and the orifice 14 with the valve seat 13 are penetrated, and the valve body 15 is arranged opposite to the valve seat 13, and the valve body 15 and the valve seal 1.
In the valve drive mechanism that performs opening and closing operations between 3 and 3, the valve seat 1 is connected to the reaction pressure responsive member side of the valve body 15 by a return spring 20.
A plunger l8 biased toward the third side is disposed so as to be able to reciprocate in the axial direction, so that the pressing force of the return spring 20 is applied to the valve body 15 via the plunger 18, and the pressing force of the return spring 20 is An electromagnetic solenoid 21 is provided to magnetically attract the plunger 18 in the weakening direction, and the pressure responsive member 4 is set to adjust the set value for opening the valve body 1S by controlling the energization of the solenoid 2.

The second problem-solving means is an application of the valve driving mechanism of the first problem-solving means, and a pressure control valve for adjusting the evaporator outlet pressure of the refrigeration cycle is constructed as follows. To explain this with reference to the reference numerals in FIG. 1, the first
A piston-shaped valve body 9 disposed in the pressure chamber 7 of the valve body 9, which adjusts the opening area of the refrigerant passage between the evaporator outlet 8 and the compressor inlet 6 by changing its position; A spring 9A biases the throttle valve 9 in a direction that increases the opening area of the refrigerant passage between the machine inlet 6, and a gas pressure acts in a direction that decreases the opening area of the refrigerant passage between the evaporator outlet 8 and the compressor inlet 6. In the pressure chamber 10, a second pressure chamber 10 communicates with a discharge passage (high pressure chamber) 17 of the compressor via a pressure guiding path 1l, a third pressure chamber 5 communicates with the first pressure chamber 7, and this third pressure chamber 5. a pressure-responsive member 2, whose one end is fixed to the pressure chamber 5 of No. 3 and is installed inside the body, and which expands and contracts depending on the difference between the internal pressure of the third pressure chamber 5 and the white meat; Response member 2
a pilot valve 15 that opens and closes the orifice 14 of the pressure guide 11 in conjunction with the pilot valve 15, which is disposed on the opposite side of the pressure-responsive member 2 with respect to the orifice 14; The plunger 18 is biased via the return spring 20, the electromagnetic solenoid 21 is capable of magnetically attracting the plunger l8 in a direction that relieves the pressing force (pressing load) of the return spring 20 against the pilot valve 15, and the electromagnetic solenoid 21 is energized and controlled. and the means to do so.

[Effect]

According to the first problem solving means, the following effects are achieved.

The pressure responsive member 2 housed in the pressure chamber 5 expands and contracts due to the difference between the external pressure around it (the pressure in the pressure chamber 5) and the internal pressure of the pressure responsive member 2 itself, and the stroke of the valve body 15 is determined by the pressure responsive It is determined at a balance between the internal and external pressure difference of the member 2 and the pressing force of the plunger l8 (pressing force of the return spring 20) arranged on the side of the reaction force responsive member.

That is, when the electromagnetic solenoid 21 is in a de-energized state, the spring force (pressing load) of the return spring 20 acting on the valve body 15 via the plunger 18 is maximum, so that the valve body 1
5 comes into pressure contact with the valve seat 13 of the orifice 14 to close the orifice 14. On the other hand, electromagnetic solenoid 2
1, the spring 2 returns to the plunger 18.
A magnetic attraction force that resists the zero force acts, and the pressing load (valve closing force) acting on the valve body 15 of the plunger 18 is weakened. Therefore, if the applied voltage of this electromagnetic solenoid is energized and controlled, the valve opening force required for the valve body 15, in other words, the valve body 1
The valve opening force of the pressure responsive member 2 acting on the pressure responsive member 5 can be adjusted as desired.

The second problem-solving means is also an application of the first problem-solving means, and has been described in detail in the Examples section, so its explanation will be omitted here.

Note that the pilot valve 1 in the second 11IM solution means
5 corresponds to the valve body 15 described in the first problem solving means. [Example] An example of the present invention will be explained with reference to the drawings. FIG. 1 is a longitudinal cross-sectional view of a pressure control valve according to a first embodiment of the present invention, which maintains the pressure at the outlet of the evaporator of the refrigeration cycle constant. Prior to this explanation, the outline of a refrigeration cycle incorporating the pressure control valve of this embodiment will be explained with reference to FIG. As shown in FIG. 3, the engine 23 and the compressor 24 are connected by a belt transmission mechanism 23A, and the rotation of the engine 23 is transmitted to the compressor 24 by the transmission mechanism 23A. A discharge pipe 25A extends from the discharge side of the compressor 24, and from the discharge pipe 25A, a condenser 26, a liquid receiver 28, an expansion valve 29,
Evaporators 30 are provided in series, and a suction pipe 31A extends from the outlet of the evaporator 30. The suction pipe 31A is connected to the inlet side of the pressure control valve 32 of this embodiment, and is connected to the inlet side of the pressure control valve 32 of the present embodiment.
A suction pipe 31 leading to the suction side of the compressor 24 on the outlet side of the compressor 24.
B will be extended.

Further, a discharge pipe line 25B branched from the discharge pipe line 25A of the compressor 24 is connected to the discharge side pressure guide line 17 (shown in FIG. 1) of the pressure control valve 24. The pressure control valve 32 serves to control the evaporator outlet pressure of the refrigeration cycle so that it does not fall below a set value.The details of this pressure control valve 32 will be explained with reference to FIG. 1. In FIG. 1, 1 is the main body of the pressure control valve 32;
has a cylindrical shape, the inlet side passage 8 in the main body l is connected to the evaporator outlet side pipe 31A, the outlet side passage 6 is connected to the compressor suction pipe 31B, and the pressure guiding line 17 is connected to the compressor suction pipe 31B. It is connected to the machine side discharge pipe 25B.

Inside the main body 1, a first pressure chamber 7 is formed which connects an inlet side passage 8 leading to the evaporator outlet and an outlet side passage 6 leading to the compressor inlet side. A piston-shaped throttle valve 9 for adjusting the opening area is mounted so as to be able to reciprocate while being biased by a spring 9A. A second pressure chamber 10 is formed at one end of the throttle valve 9 on the opposite side from the spring 9A. Furthermore, a third pressure chamber 5 is formed adjacent to the first pressure chamber 7 and communicating with this pressure chamber. Inside the pressure chamber 5, a pressure responsive member 2 is provided so as to be expandable and contractible. The pressure responsive member 2 has a bellows 2A as a main body, and a bellows 2A as a main body.
The inside of the chamber is defined as an internal pressure chamber 4.

This internal pressure chamber 4 is equipped with a spring 3 and sealed at a predetermined pressure, and the pressure responsive member 2 expands and contracts due to the pressure difference between the pressure chamber 5 and the internal pressure chamber 4. A valve stem 12 is connected to the center of the free end of the pressure responsive member 2 (one end on the opposite side from the first pressure chamber 7), and a ball valve (pilot valve) 15 is connected to the tip of the valve stem 12. be done. The valve n12 and the ball valve 15 pass through one end of the partition wall of the pressure chamber 5, the throttle valve guide 11 adjacent to the pressure chamber 5, and the orifice 14, and the ball valve 15 is located in the valve chamber 16. The valve chamber 16 is connected to a compressor discharge line 25 shown in FIG. 3 via a pressure guide line 17.
B, and also communicates with a second pressure chamber 10 at the rear of the throttle valve 9 via an orifice 14 and a throttle valve pressure channel 11.

Further, a plunger 18 is arranged within the valve chamber 16 so as to face the ball valve 15 and the valve stem 12 . This plunger 18
The one end on the opposite ball valve side is urged by the return spring 20 and presses the ball valve 15, and this pressing force causes the ball valve 15 to close.
comes into pressure contact with the valve seat 13, and the orifice 14 is closed. A solenoid 21 is attached around the plunger 18. When this solenoid 21 is energized, the plunger 18, which forms part of the magnetic circuit, acts as a counter-ball valve so as to weaken the force of the return spring 20 against the ball valve 15. It exerts its suction force on the side.

Next, the operation of the pressure control valve of this embodiment will be explained. In the steady state of the refrigeration cycle, the compressor is rotating. In this case, when the evaporator outlet pressure is equal to or higher than the set value P, the voltage V1 applied to the solenoid 21 is Ov. Therefore, the ball valve 19 receives the force Fbi of the plunger 18 urged by the return spring 20, and is pressed against the valve seat 13, closing the orifice 14 (see FIG. 5).
．． In this state, the pressure responsive member 2 applies a force corresponding to the surrounding pressure (set value) P to the valve stem 12 and the connected ball valve 15.
is energized to balance the pressing force Fw of the opposing plunger 18 (see FIG. 6). As a result, ball valve 1
5, since the orifice 14 is closed, a part of the compressor discharge refrigerant flowing in from the pressure guide path 17 does not reach the pressure chamber 10 for operating the pressure throttle valve 9.
The throttle valve 9 moves back in the direction of opening the outlet passage 6 (leftward in FIG. 1) by the force of the spring 9A, and the outlet passage 6 communicates with the inlet passage 8 in a fully open state. Therefore, in this state,
The refrigerant from the evaporator flows into the low pressure chamber side of the compressor via passages 8 and 6.

Next, when voltage is applied to the solenoid 21 (V=Vz
), the plunger 18 is attracted in the direction of opening the ball valve 15 (to the right in FIG. It will weaken it. However, since the set load of the return spring 20 (the load when the solenoid 21 is in the OFF state) is set higher than the maximum suction force of the solenoid 21 (maximum voltage in the operating range, for example when Del 2V is applied), the plunger 18 cannot be opened. The stroke toward the valve is slight. In addition, since the force pushing the ball valve 19 is weakened by the suction of the plunger 18, the force Fl of the pressure responsive member 2 pushing the ball valve 19 is reduced as shown in FIG. ，! The ball valve 19 is opened. As a result, the discharged refrigerant flowing from the pressure guiding path 17 flows through the orifice 1.
4. By flowing into the pressure chamber 10 through the throttle valve pressure path 11 and overcoming the biasing force of the spring 9A applied to the throttle valve 9,
The throttle valve 9 is moved in a direction to throttle the space between the passage 6 and the passage 8 (to the right in FIG. 1). Furthermore, as the pressure in the first pressure chamber 7 increases, the pressure (P) in the pressure chamber 5 around the pressure responsive member communicating with the suction pressure chamber 7 increases (becomes higher than the initial setting pressure).

In this way, when the pressure in the pressure chamber 5 increases, the pressure responsive member 2 contracts, and the force Fl, 2 pushing the ball valve 15 decreases and becomes balanced with the pushing force of the plunger 18 again. At that time, the pressure in the suction pressure chamber 7 (set pressure P) when it is in a balanced and stable state, in other words, the evaporator outlet pressure increases as the voltage applied to the solenoid 21 increases, as shown in FIG. The applied voltage Ov can be increased arbitrarily, or can be arbitrarily decreased as the applied voltage decreases.
Sometimes it can be returned to the initial setting pressure, as shown in Figure 2.
This is the second embodiment, and the basic structure is the same as the first embodiment. The difference is that a conical spring 22 is provided between the ball valve 15 and the plunger l8, and the deflection of the conical spring is changed. Accordingly, the pressing load on the ball valve 15 is changed.

According to each of the embodiments described above, the evaporator outlet pressure of the refrigeration cycle can be maintained at the set value. In addition, when variably adjusting the set value of the evaporator outlet pressure, the pressing load of the plunger 18 (spring 20) that presses the pilot valve 15 toward the valve seat side is electromagnetically adjusted without changing the set length of the pressure responsive member 2. It is only necessary to adjust by force, and as a result, the maximum stroke of the pressure-responsive member 2 can be reduced and the number of ridges can be reduced. Therefore, the cost and size of the pressure responsive member 2 can be reduced by about 30 to 40% compared to the conventional system. Figure 8 shows the relationship between the maximum stroke and the number of peaks of the pressure responsive member. Further, FIG. 6 shows the force in the opening direction (
Fig. 7 shows the relationship between the set valve opening force and the electromagnetic solenoid 2.
The relationship between the set value of the evaporator outlet pressure P when the applied voltage of 1 is changed is shown. [Effects of the Invention] As described above, according to the present invention, by changing the voltage applied to the electromagnetic solenoid, the pressing force (valve closing force) of the return spring against the valve seat that resists the pressure responsive member can be adjusted. The setting value for opening the valve body can be adjusted arbitrarily without changing the set length of the response member. Therefore, the maximum stroke of the pressure-responsive member can be reduced, the number of ridges for expansion and contraction can be reduced, and the shape of the pressure-responsive member can be made smaller and the manufacturing cost can be reduced.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view showing a first embodiment of the present invention, FIG. 2 is a longitudinal sectional view showing a second embodiment of the invention, and FIG. 3 is a structure of a refrigeration cycle to which each of the above embodiments is applied. Figure 4 is a vertical cross-sectional view showing a conventional example of a pressure control valve, and Figure 5 shows the relationship between the applied voltage of the electromagnetic solenoid used in each of the above embodiments and the pressing force of the return spring that provides the valve-closing force. 6 is a diagram showing the relationship between the ball valve opening force for changing the ambient pressure P of the pressure-responsive member in each of the above embodiments, and FIG. 7 is a diagram showing the applied voltage of the electromagnetic solenoid used in each of the above embodiments. FIG. 8 is an explanatory diagram showing the relationship between the maximum stroke and the number of peaks of the pressure-responsive member used in each of the above embodiments in comparison with a conventional example. 1...Main body of pressure control valve, 2...Pressure responsive member, 5
...pressure chamber for operating the pressure-responsive member (third pressure chamber),
6... Compressor inlet side passage, 7... First pressure chamber, 8
... Evaporator outlet side passage, 9... Throttle valve, 9A...
Spring for urging throttle valve, 10...Second pressure chamber, l1.
...Pressure path, 12...Valve stem, work 3...Valve seat, 1
4... Orifice, 15... Valve body (pilot valve)
, 18... Plunger, Figure 4 High S Figure] Cause\Noreno1 To F'P'Il11! ffi (V no. 6
Four maximum strokes

Claims (1)

[Scope of Claims] 1. A pressure-responsive member that expands and contracts in response to a difference between the surrounding pressure and its own internal pressure when the surrounding pressure changes, and the pressure-responsive member is fixed at one end. It has an internal pressure chamber for operating a pressure responsive member, and a valve stem with a valve body provided at the free end of the pressure responsive member, and the valve stem is passed through the pressure chamber and an orifice with a valve seat. , in a valve drive mechanism in which the valve body is disposed opposite to a valve seat, and opening and closing operations between the valve body and the valve seat are performed by the expansion and contraction movement of the pressure responsive member. A plunger urged toward the valve seat side by a return spring is disposed on the reaction force response member side of the valve body so as to be able to reciprocate in the axial direction, and the pressing force of the return spring is applied to the valve body through this plunger. an electromagnetic solenoid that magnetically attracts the plunger in a direction in which the pressing force of the return spring is weakened, and the pressure-responsive member opens the valve body by controlling the energization of the electromagnetic solenoid. A pressure-sensitive valve drive mechanism characterized by being configured to adjust a value. 2. A piston-shaped valve body placed in the first pressure chamber between the evaporator outlet and the compressor inlet of the refrigeration cycle.By changing its position, the refrigerant passage opens between the evaporator outlet and the compressor inlet. A throttle valve that adjusts the area; a spring that biases the throttle valve in a direction that increases the opening area of the refrigerant passage between the evaporator outlet and the compressor inlet; and a refrigerant passage opening area between the evaporator outlet and the compressor inlet. A pressure chamber in which gas pressure is applied in the direction of decreasing the pressure, a second pressure chamber communicating with the discharge passage (high pressure chamber) of the compressor via a pressure path, and a third pressure chamber communicating with the first pressure chamber. a pressure-responsive member having one end fixed to and housed in the third pressure chamber and expanding and contracting based on the difference between the third pressure chamber and its own internal pressure; and a pressure-responsive member attached to the free end of the pressure-responsive member. , a pilot valve that operates in conjunction with the pressure responsive member to open and close the orifice of the pressure guiding path; and a pilot valve that is disposed on the opposite side of the pressure responsive member with respect to the orifice and that connects the pilot valve to the valve seat of the orifice. a plunger that is biased toward the side via a return spring; an electromagnetic solenoid that can magnetically attract the plunger in a direction that relieves the pressing force of the return spring against the pilot valve; and means for controlling energization of the electromagnetic solenoid. A pressure control valve for a refrigeration cycle characterized by: