JP2011202709A - Check valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively suppress a hunting phenomenon even in when the differential pressure between the front and rear of a check valve is small.SOLUTION: This check valve 1 includes: a cylindrical body 10 having an introduction port 23 of a refrigerant on an upstream side and a lead-out hole 24 of the refrigerant on a side part; a valve seat 22 provided between the introduction port 23 in the body 10 and the lead-out hole 24; and a valve element 12 having an attachment/detachment part 32 slidably stored in the body 10 and attached and detached to and from the valve seat 22 in order to open and close a first valve part, and a sliding part opening and closing a second valve part having an effective pressure receiving diameter larger than the first valve part depending on a slidable contact position with an inner peripheral surface of the body 10, and opening and closing the lead-out hole 24. When the length of the sliding part on the first valve part side compared to the lead-out hole 24 in the valve close state of the first valve part is L, the effective pressure receiving diameter of the first valve part is a, an inside diameter of the body is b, and an outside diameter of the sliding part is c, the following relationship is satisfied; L≥4b(b-c)/a.

Description

  The present invention relates to a check valve that is disposed in a refrigerant passage and restricts the flow of refrigerant in one direction.

  In general, an air conditioner for an automobile includes a variable capacity compressor (also simply referred to as a “compressor”) capable of varying a refrigerant discharge capacity so that a constant cooling capacity is maintained regardless of the engine speed. . In this compressor, a piston for compression is connected to a swing plate attached to a rotary shaft that is driven to rotate by an engine, and the discharge amount of the refrigerant is changed by changing the stroke of the piston by changing the angle of the swing plate. adjust. The angle of the swing plate can be continuously changed by introducing a part of the discharged refrigerant into the sealed crank chamber and changing the balance of pressure applied to both surfaces of the piston.

  Since such a compressor can be a heavy load on the engine, it is necessary to reduce the load torque of the compressor at a high load when the engine power is to be directed to the driving force of the vehicle, such as when the vehicle is accelerating or running uphill. There is. Conventionally, compressors equipped with electromagnetic clutches that transmit or cut off the driving force of the engine so that this load torque can be temporarily cut have been widely adopted. So-called clutchless compressors that are directly connected to each other are becoming mainstream. When the engine is heavily loaded, the pressure in the crank chamber is increased to minimize the angle of the swing plate, and the compressor is shifted to the minimum capacity operation state. This minimizes the load torque of the compressor.

  However, even if the compressor shifts to the minimum capacity operation in this manner, the discharge capacity cannot normally be completely zero because the swinging plate has a slight inclination. For this reason, the evaporator located in the downstream of a compressor may freeze by the slight refrigerant | coolant flow especially in low temperature environments, such as winter. Further, when the discharge capacity of the compressor rapidly decreases, there is a possibility that the pressure at the outlet of the compressor temporarily becomes higher than the pressure in the discharge chamber and the discharged refrigerant flows back to the discharge chamber. Therefore, in general, a check valve is provided in the passage between the outlet of the compressor and the discharge chamber to prevent outflow of the refrigerant discharged from the compressor and the reverse flow of the refrigerant to the discharge chamber during the minimum capacity operation. .

  By the way, even if the check valve closes the outlet of the discharge chamber in the minimum capacity operation state as described above, the pressure in the discharge chamber (discharge pressure) gradually increases because the compressor compresses the minimum capacity. To go. When the force in the valve opening direction due to the discharge pressure acting on the valve body of the check valve exceeds the force in the valve closing direction due to the spring, the check valve starts to open. On the other hand, when the check valve is opened in this way, the refrigerant flows downstream and the pressure in the discharge chamber decreases, so the check valve starts to close. That is, when the compressor is in the minimum capacity operation state, a hunting phenomenon in which opening and closing of the minute opening is repeated occurs in the check valve, which causes noise.

  Therefore, there is a technology that suppresses the hunting phenomenon by varying the opening area when the check valve is opened by the gradually increasing discharge pressure and providing a flow rate adjustment function that restricts the flow rate of refrigerant flowing downstream when the check valve is opened. It has been proposed (see, for example, Patent Document 1). Specifically, the first valve portion and the second valve portion having a larger effective pressure receiving diameter are provided in stages from the upstream side of the check valve, and the valve body of the second valve portion includes a first valve portion. A tapered portion is formed toward the valve portion. As a result, when the first valve portion is opened and the second valve portion is opened, the opening degree of the second valve portion gradually increases, the flow rate of the refrigerant is reduced, and hunting reduction is suppressed. The

JP-A-2005-249154

  However, even in such a configuration, when the opening degree of the second valve portion is opened, the pressure on the upstream side decreases, so that the first valve portion again operates in the valve closing direction. That is, although the valve opening performance is improved by gradually opening the valve portion, if the second valve portion opens soon after the first valve portion opens, the pulsation of the refrigerant flow still remains. there is a possibility.

  The present invention has been made in view of such problems, and an object thereof is to more effectively suppress the hunting phenomenon of the check valve.

  In order to solve the above problems, a check valve according to an aspect of the present invention is disposed in a refrigerant passage to restrict the flow of refrigerant in one direction, and has an inlet for refrigerant on the upstream side. A cylindrical body provided with a refrigerant outlet hole on the side, a valve seat provided between the inlet and the outlet hole in the body, and slidably accommodated in the body. The opening / closing opening and closing of the second valve portion having an effective pressure receiving diameter larger than that of the first valve portion is determined by the sliding contact position between the body and the inner peripheral surface of the body. A valve body configured to open the second valve part after the first valve part is opened by a predetermined amount, and a back part of the valve body in the body. A compartment-formed back pressure chamber, and a biasing member that is disposed in the back pressure chamber and biases the valve body in the valve closing direction.

In the closed state of the first valve portion, the length of the sliding portion on the first valve portion side of the lead-out hole is L, the effective pressure receiving diameter of the first valve portion is a, and the inner diameter of the body is b When the outer diameter of the sliding portion is c, the following equation (1) is satisfied.
L ≧ 4b (bc) / a (1)
Here, the “effective pressure receiving diameter” may be a diameter of a portion that substantially receives a differential pressure between an upstream pressure and a downstream pressure in each valve portion.

  According to this aspect, after the first valve portion is opened, the second valve portion does not start opening unless the valve body is displaced in the valve opening direction by the length L. That is, the refrigerant flow rate does not increase until the valve body is displaced by the length L, and the pressure on the upstream side of the second valve portion can be increased. That is, the pressure on the upstream side of the valve body is sufficiently increased before the second valve portion is opened after the first valve portion is opened. As a result, when the first valve portion operates in the valve closing direction after the second valve portion is opened, resistance due to the pressure increase is applied, and the valve closing operation is suppressed from becoming sharp. Thereby, vibration of the valve body can be suppressed and pulsation of the refrigerant flow rate can be suppressed.

  According to the present invention, the hunting phenomenon of the check valve can be more effectively suppressed.

It is a front view of the check valve concerning an embodiment. It is a bottom view of a check valve. It is AA arrow sectional drawing of FIG. It is the B section enlarged view of FIG. It is a figure for demonstrating the detail of the structure of a non-return valve.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
The check valve according to the present embodiment is installed in a variable capacity compressor (simply referred to as “compressor”) that compresses the refrigerant circulating in the refrigeration cycle of the vehicle air conditioner, and includes an outlet between the compressor and a discharge chamber. It is arrange | positioned by the refrigerant | coolant channel | path between them, and controls the reverse flow of a refrigerant | coolant. In addition to the compressor, the vehicle air conditioner includes an external heat exchanger such as a condenser or a gas cooler, an expansion device, an evaporator, and the like.

  The compressor introduces refrigerant gas introduced from the evaporator side into the suction chamber into the cylinder and compresses it, and discharges high-temperature and high-pressure refrigerant from the discharge chamber to the condenser side. Part of the discharged refrigerant is introduced into the crank chamber via a variable displacement compressor control valve (simply referred to as “control valve”), and is used for compressor capacity control. The control valve is configured as a solenoid-driven electromagnetic valve, and is energized and controlled by a control unit (not shown) via a predetermined drive circuit. The check valve is fixed to a refrigerant passage provided in the housing of the compressor. In addition, since it is common about the structure of the compressor except a non-return valve, and the structure of the other apparatus which comprises a refrigerating cycle, it abbreviate | omits about the description.

  FIG. 1 is a front view of a check valve according to the embodiment. FIG. 2 is a bottom view of the check valve. 3 is a cross-sectional view taken along arrow AA in FIG. FIG. 4 is an enlarged view of a portion B in FIG. FIG. 5 is a diagram for explaining the details of the structure of the check valve. In the following description, for the sake of convenience, the positional relationship of each component may be expressed based on the illustrated state.

  As shown in FIG. 3, the check valve 1 is configured to slidably accommodate a valve body 12 in a bottomed cylindrical body 10. The check valve 1 has a first valve portion provided at the refrigerant inlet and a second valve portion provided at the refrigerant outlet. The effective pressure receiving diameter of the second valve portion is larger than that of the first valve portion, and when the valve body 12 strokes in the body 10, these valve portions are configured to open in stages. .

  The body 10 is configured by connecting a stepped cylindrical first body 14 and a bottomed cylindrical second body 16 in the axial direction so as to abut each other's opening. The first body 14 has a reduced diameter portion 18 whose outer diameter is reduced on the second body 16 side. The second body 16 is joined to the first body 14 by the upper end opening of the second body 16 being extrapolated to the reduced diameter portion 18 and being caulked from the outside. A boss portion 20 protrudes from the lower end opening edge of the reduced diameter portion 18, and a valve seat 22 is constituted by the tip surface of the boss portion 20. The valve body 12 and the valve seat 22 constitute a “first valve portion”. The upper end opening of the first body 14 opposite to the boss 20 is an introduction port 23, and introduces a refrigerant having a discharge chamber pressure Pdh discharged from the discharge chamber of the compressor.

  As shown in FIG. 1, four lead-out holes 24 communicating between the inside and the outside are formed in the side portion of the second body 16 at equal intervals in the circumferential direction. Each lead-out hole 24 has a substantially rectangular shape, and is longer than the length in the longitudinal direction of the second body 16 (also referred to as “length of the lead-out hole 24”) (also referred to as “width of the lead-out hole 24”). Are large). The four outlet holes 24 are formed every 90 degrees in the circumferential direction of the second body 16 and are opened and closed depending on the stroke position of the valve body 12. The valve hole 25 and the valve body 12 formed in the upper part of the four outlet holes 24 constitute a “second valve portion”. A refrigerant having an outlet pressure Pdl is led out from the outlet hole 24. As shown in FIG. 2, communication holes 26 communicating the inside and the outside are also formed at equal intervals in the peripheral edge of the bottom of the second body 16. As shown in FIG. 3, a boss portion 28 projecting inward is provided at the center of the bottom portion of the second body 16.

  The valve body 12 has a bottomed cylindrical main body 30 and is supported so as to be slidable in the axial direction along the inner wall of the second body 16. The outer diameter of the bottom portion of the main body 30 is reduced stepwise, and the peripheral portion of the bottom surface forms an attachment / detachment portion 32 that is attached to and detached from the valve seat 22. The valve body 12 is attached to and detached from the valve seat 22 by the attaching / detaching portion 32 to open and close the first valve portion. In the closed state of the first valve portion, as shown in the figure, the attaching / detaching portion 32 and the valve seat 22 are in a surface contact state, and both form an annular contact portion having a predetermined width in the radial direction.

  As shown in FIG. 4, the valve body 12 includes a sliding portion 34 that slides along the inner peripheral surface 33 of the second body 16 and a tapered portion 35 that decreases in diameter from the sliding portion 34 toward the bottom. . The taper portion 35 has a first taper portion 36 and a second taper portion 38. The inclination angle of the taper part 35 with respect to the sliding part 34 is very small in the first taper part 36 and slightly larger in the second taper part 38. With such a configuration, when the first valve portion is opened and the second valve portion is opened, the opening degree of the second valve portion gradually increases, and the flow rate of the refrigerant is reduced to reduce hunting. Is suppressed.

  Returning to FIG. 3, the effective pressure receiving diameter “c” in the second valve portion is larger than the effective pressure receiving diameter “a” in the first valve portion of the valve body 12. In the valve closing state of the first valve portion as shown in the drawing, the valve body 12 has its sliding portion 34 located on the upstream side of the lead-out hole 24 to hold the second valve portion in the valve closing state. . When the first valve portion is opened and the valve body 12 is stroked in the direction of increasing the opening degree, the second taper portion 36 and the second taper portion 38 are sequentially positioned in the outlet hole 24 so that the second The valve portion is gradually opened to allow the introduction port 23 and the outlet hole 24 to communicate with each other.

  That is, the valve body 12 opens and closes the second valve portion depending on the sliding contact position with the inner peripheral surface of the second body 16, and the second valve portion has the first valve portion opened by a predetermined amount. It is opened after a while. The discharge chamber pressure Pdh of the refrigerant discharged from the discharge chamber of the compressor is gradually reduced through the first valve portion and the second valve portion at the beginning of opening of each valve portion, and becomes the outlet pressure Pdl. And is derived from the outlet of the compressor. When each valve part is fully open, the discharge chamber pressure Pdh is substantially equal to the outlet pressure Pdl.

  A back pressure chamber 40 is defined on the back portion of the valve body 12 in the body 10 so as to be surrounded by the valve body 12 and the second body 16. Between the bottom of the valve body 12 and the bottom of the second body 16 in the back pressure chamber 40, a spring 42 (corresponding to an “urging member”) that biases the valve body 12 in the valve closing direction is interposed. ing. As described above, since the effective pressure receiving diameter a of the first valve portion is smaller than the effective pressure receiving diameter c of the second valve portion, the load of the spring 42 for maintaining the valve closed state is set to be small. be able to. That is, a spring having a small load can be used. Further, by providing the communication hole 26 at the bottom of the second body 16 as described above, the differential pressure inside and outside the back pressure chamber 40 is substantially zero.

  By the way, although the hunting phenomenon can be suppressed by opening the first valve portion and the second valve portion in stages as described above, the opening degree of the second valve portion is opened. Since the upstream pressure decreases, the first valve portion operates again in the valve closing direction. That is, although the valve opening performance is improved by gradually opening the valve portion, if the second valve portion is opened soon after the first valve portion is opened, the refrigerant flow pulsation still remains. there is a possibility.

  Therefore, in the present embodiment, the pressure on the upstream side of the valve body 12 is sufficiently increased after the first valve portion is opened and before the second valve portion is opened. And when the 1st valve part operates in the valve closing direction after the 2nd valve part opens, resistance by the pressure rise is given and it suppresses that valve closing operation becomes sharp. . Thereby, the vibration of the valve body 12 is suppressed, and the pulsation of the refrigerant flow rate is suppressed.

  That is, as shown in FIG. 4, the check valve 1 is configured such that the distance between the tapered portion 35 and the outlet hole 24 is sufficiently large when the first valve portion is closed. In other words, the length L of the sliding portion between the sliding portion 34 and the second body 16 on the first valve portion side than the outlet hole 24 (also referred to as “the length of the lap allowance”) L is larger. Even if the valve portion opens, the second valve portion does not open unless the valve body 12 strokes the length L of the lapping margin. In the present embodiment, the length L of the lapping margin is configured to be larger than the length T of the tapered portion 35. When the first valve portion is opened from the state shown in the drawing and the valve body 12 is stroked by the length L of the lap allowance, the second valve portion begins to open.

In this embodiment, by appropriately setting the length L of the lap allowance, the upstream pressure is sufficiently increased from the opening of the first valve portion to the opening of the second valve portion. I try to increase it. That is, as shown in FIG. 4, the length of the lapping margin when the first valve portion is in the closed state is L, the effective pressure receiving diameter of the first valve portion is a, second, as shown in FIG. When the inner diameter of the body 16 is b and the outer diameter of the sliding portion 34 of the valve body 12 is c, the check valve 1 is configured so that the following formula (1) is established.
L ≧ 4 · b (bc) / a (1)

The reason for setting the dimensions in this way is as follows. First, consider a boundary value that causes flow resistance to act on the refrigerant flowing through the gap passage between the valve body 12 and the body 10 when the first valve portion is opened. Here, if the second valve portion is opened when the first valve portion is opened, flow resistance does not occur. Therefore, the second valve portion is closed in the gap passage when the first valve portion is opened. It shall be formed when In this case, if the lift amount from the valve seat 22 of the valve body 12 when the opening area of the first valve portion becomes equal to the cross-sectional area of the gap passage is x in the figure, the following formula (2) is established.
π · a · x = π · b · (bc) (2)

  That is, when x = b (bc) / a, the opening area of the first valve portion is equal to the cross-sectional area of the gap passage. For this reason, even if the valve body 12 is lifted further, if the wrap margin exists, flow resistance is given to the refrigerant. In the present embodiment, the length L of the lap allowance when the first valve portion is in the closed state is set to be four times or more of x as in the above formula (1), and the flow resistance can be reliably imparted to the refrigerant. It is what I did. The coefficient “4” is set as an appropriate value through experiments and the like. That is, generally, when the fluid is led out from a narrow passage to a wide passage, flow resistance is not generated if the cross-sectional area ratio of the flow path is four times or more. Here, the flow resistance is ensured by making the cross-sectional area ratio of the flow path 4 times or more in the situation where the refrigerant is led from the wide passage to the narrow passage, and the upstream pressure is sufficiently increased. The second valve portion is opened after accumulating pressure.

  With the above-described configuration, the check valve 1 is configured such that when the detachable portion 32 is seated on the valve seat 22 and the first valve portion is in the closed state, the outlet hole 24 is closed by the valve body 12. The valve part 2 is also closed. At this time, the valve body 12 is positioned in the valve closing direction of the second valve portion by the length L of the lapping margin. Therefore, even if the valve body 12 is lifted from the valve seat 22 and the first valve portion is opened, the second valve portion is closed until the valve body 12 is lifted by the length L of the lap allowance. The state is maintained, and the valve starts to open after further lifting. That is, when the compressor is operating at a minimum capacity and the like, while the discharge chamber pressure Pdh is small, the valve body 12 receives a load due to the pressure with a small effective pressure receiving diameter C. The valve portion can be held in a closed state, and the function as the check valve 1 can be effectively exhibited. On the other hand, when the discharge chamber pressure Pdh increases to some extent and the first valve portion starts to open, the valve body 12 receives a load due to the pressure with a large effective pressure receiving diameter D, so that the second valve portion relatively quickly. It will be opened. As a result, the check valve 1 can be promptly shifted to the fully open state, and the refrigerant can flow without causing a large pressure loss.

  In addition, when the second valve portion is opened, the second valve portion is opened while gradually increasing the gap passage between the body 10 and the valve body 12, thereby reducing the change in the flow resistance of the refrigerant. Thereby, it can suppress that a pulsation generate | occur | produces in the flow volume of the refrigerant | coolant which flows through each valve part. That is, when the second valve portion is opened, a flow rate adjusting function that gradually increases the valve opening degree can be exhibited, and hunting due to self-excited vibration of the valve body 12 can be prevented or suppressed. As a result, the valve opening operation of the valve body 12 can be stably maintained.

  Furthermore, after the first valve portion is opened in this manner, the valve body 12 is displaced in the valve opening direction until the second valve portion starts to open. The upstream pressure is increased. As a result, when the first valve portion operates in the valve closing direction after the second valve portion is opened, resistance due to the pressure increase is applied, and the valve closing operation is suppressed from becoming sharp. By repeating such an action, the vibration of the valve body 12 can be suppressed and the pulsation of the refrigerant flow rate can be suppressed.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the specific embodiments, and various modifications can be made within the scope of the technical idea of the present invention. Nor.

  In the above embodiment, the check valve 1 is described as being installed in the housing of the clutchless variable displacement compressor. However, the check valve 1 may be installed in the clutch variable displacement compressor or other than the variable displacement compressor. You may install in the compressor of. Or you may install in the other site | parts of the refrigerating cycle, such as in the piping which connects a variable capacity compressor and a condenser. Further, the present invention is not limited to a vehicle equipped with an engine of an internal combustion engine, and may be installed in a refrigeration cycle of a hybrid vehicle using an internal combustion engine and an electric motor or an electric vehicle. Furthermore, you may install not only in the refrigerating cycle of an automotive air conditioner but in an indoor other air conditioner.

  DESCRIPTION OF SYMBOLS 1 Check valve, 10 body, 12 Valve body, 22 Valve seat, 23 Introduction port, 24 Outlet hole, 26 Communication hole, 30 Main body, 32 Detachable part, 33 Inner peripheral surface, 34 Sliding part, 35 Tapered part, 40 Back pressure chamber, 42 springs.

Claims (3)

In a check valve disposed in the refrigerant passage to restrict the flow of the refrigerant in one direction,
A cylindrical body having a refrigerant inlet on the upstream side and a refrigerant outlet hole on the side,
A valve seat provided between the inlet and the outlet hole in the body;
The first valve portion is slidably housed in the body and is attached to and detached from the valve seat to open and close the first valve portion, and the sliding position between the inner peripheral surface of the body and the first valve portion. And a sliding portion that opens and closes the outlet hole by opening and closing the second valve portion having a larger effective pressure receiving diameter, and the second valve portion after the first valve portion is opened by a predetermined amount. A valve element configured to be opened,
A back pressure chamber defined in the back of the valve body in the body;
A biasing member disposed in the back pressure chamber and biasing the valve body in a valve closing direction;
With
In the closed state of the first valve portion, the length of the sliding portion that is closer to the first valve portion than the outlet hole is L, the effective pressure receiving diameter of the first valve portion is a, and the body A check valve characterized by having the relationship of the following formula (1) where b is the inner diameter and c is the outer diameter of the sliding portion.
L ≧ 4b (bc) / a (1)   2. The check according to claim 1, wherein a communication hole that communicates the inside and outside of the back pressure chamber is provided, and the differential pressure inside and outside of the back pressure chamber is substantially zero. valve.   The check valve according to claim 1 or 2, wherein the check valve is disposed in a refrigerant passage between an outlet of the variable capacity compressor and the discharge chamber, and restricts a reverse flow of the refrigerant from the outlet side to the discharge chamber. .

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