Expansion valve

Abstract

Provided is an expansion valve which exhibits high valve-opening adjustment accuracy.　An expansion valve equipped with a valve housing 10 in which an intake port 12, through which a coolant from a condenser H1 passes, and a discharge port 11, through which a coolant heading toward an evaporator H2 passes, are formed, and also equipped with a valve body 51 driven by a solenoid 80, a valve seat 10a on which the valve body 51 is seated, and a biasing means 18 for biasing the valve body 51 in the valve-closing direction, wherein a space S1 is formed on the valve-opening direction side of the valve body 51, and the coolant on the valve-closing direction side of the valve body 51 flows into the space S1.

Description

[Technical field]

[0001] The present invention relates to an expansion valve for use in an air conditioning system. [Background technology]

[0002] An air conditioning system is mainly composed of a compressor that compresses refrigerant to convert it into high-temperature, high-pressure superheated vapor, a condenser that cools the refrigerant sent from the compressor to convert it into a high-temperature, high-pressure supercooled liquid, an expansion valve that expands the refrigerant sent from the condenser to convert it into low-temperature, low-pressure wet vapor, and an evaporator that heats the refrigerant sent from the expansion valve to convert it into saturated vapor, and is equipped with a refrigeration cycle in which the refrigerant circulates through the compressor, condenser, expansion valve, and evaporator in that order.

[0003] For example, the expansion valve in Patent Document 1 is an electronic expansion valve, in which the valve element is driven in the valve opening direction by the electromagnetic force of the solenoid against the biasing force of the biasing means, and the valve opening between the valve element and the valve seat formed in the valve housing can be adjusted. Also, the current value applied to the solenoid is set based on the temperature and pressure of the refrigerant after passing through the condenser, and the degree of subcooling of the condenser is maintained constant by adjusting the valve opening.

[0004] In addition, a system is also known in which the opening degree of an expansion valve is adjusted based on the temperature and pressure of the refrigerant before and after passing through an evaporator, thereby adjusting the dryness of the wet steam so that all the refrigerant becomes saturated vapor after passing through the evaporator. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2001-153498 A (page 3, figure 1) Summary of the Invention [Problem to be solved by the invention]

[0006] In an expansion valve such as that described in Patent Document 1, the valve orifice is closed by a valve body and a valve seat, and thus the valve orifice can be closed reliably. However, because a high-pressure primary-pressure refrigerant is supplied to the valve orifice from the condenser, the valve body is subjected to a force due to the pressure of the refrigerant in addition to the driving force of the solenoid in the valve opening direction, and there is a risk that the valve opening degree in response to the current value applied to the solenoid will vary slightly depending on the pressure of the refrigerant.

[0007] The present invention has been made in consideration of such problems, and has an object to provide an expansion valve with high accuracy in adjusting the valve opening degree. [Means for solving the problem]

[0008] In order to solve the above problems, the expansion valve of the present invention comprises: a valve housing having an inlet port through which a refrigerant from a condenser passes and an outlet port through which a refrigerant to an evaporator passes; A valve body actuated by a solenoid; a valve seat on which the valve body is seated; and a biasing means for biasing the valve body in a valve closing direction. A space is formed on the valve opening side of the valve body, and refrigerant on the valve closing side of the valve body flows into the space. With this, the refrigerant on the closing side of the valve seat flows into the space on the opening side of the valve disc, so the effect on the operation of the valve disc of the pressure difference between the high pressure primary pressure sent to the expansion valve and the low pressure secondary pressure on the evaporator side during operation of the air conditioning system is small. Also, the valve disc strokes accurately in response to the current value, so the accuracy of the opening adjustment by the valve disc is high.

[0009] The biasing means may be disposed in the space. According to this, the biasing means can be disposed by utilizing the space into which the refrigerant flows, so that the expansion valve can be configured compactly.

[0010] The outlet port may be provided on the valve closing direction side of the valve seat, and a communication passage may be formed that communicates between the space and the outlet port. This allows the refrigerant at the secondary pressure on the evaporator side to flow from the outlet port formed in the valve housing through the communication passage into the space.

[0011] The communication passage may be formed in the valve body. According to this, since the communication passage is formed in the valve body, the processing is simpler than forming the communication passage in the valve housing.

[0012] The space and the inlet port may be separated by a bellows. This makes it possible to separate the space and the inlet port with a simple structure.

[0013] An effective pressure-receiving area of ​​the valve body and an effective pressure-receiving area of ​​the bellows may be equal to each other. With this, the refrigerant pressure acting on the valve element from both sides in the drive direction of the solenoid is cancelled, so the operation of the solenoid is not affected by the refrigerant pressure. Therefore, the flow rate of the refrigerant sent to the evaporator can be finely changed by adjusting the valve opening degree by the balance between the electromagnetic force of the solenoid and the biasing force of the biasing means. [Brief description of the drawings]

[0014] [Figure 1] 1 is a schematic diagram showing a refrigeration cycle to which an expansion valve according to a first embodiment of the present invention is applied. [Diagram 2] 1 is a cross-sectional view showing the structure of an expansion valve according to a first embodiment of the present invention. [Diagram 3] FIG. 2 is a cross-sectional view showing the expansion valve of the first embodiment in a closed state. [Figure 4] FIG. 2 is a cross-sectional view showing a state in which the expansion valve of the first embodiment is opened. [Diagram 5] FIG. 4 is a cross-sectional view showing the structure of an expansion valve according to a second embodiment of the present invention. [Figure 6] FIG. 11 is a cross-sectional view showing a state in which the expansion valve of the second embodiment is closed. [Figure 7] FIG. 11 is a cross-sectional view showing a state in which the expansion valve of the second embodiment is opened. [Figure 8] FIG. 11 is a cross-sectional view showing the structure of an expansion valve according to a third embodiment of the present invention. [Figure 9] FIG. 11 is a cross-sectional view showing the structure of an expansion valve according to a fourth embodiment of the present invention. [Figure 10] FIG. 11 is a cross-sectional view showing the structure of an expansion valve according to a fifth embodiment of the present invention. [Figure 11] FIG. 11 is a cross-sectional view showing the structure of an expansion valve according to a sixth embodiment of the present invention. [Figure 12] FIG. 11 is a cross-sectional view showing the structure of an expansion valve according to a seventh embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An expansion valve according to an embodiment of the present invention will be described below with reference to the accompanying drawings. EXAMPLES

[0016] An expansion valve according to a first embodiment will be described with reference to Fig. 1 to Fig. 4. In the following description, the left and right sides as viewed from the front side of Fig. 2 will be referred to as the left and right sides of the expansion valve. In particular, the left side of Fig. 2 on which the valve housing 10 is arranged will be referred to as the left side of the expansion valve, and the right side of Fig. 2 on which the solenoid 80 is arranged will be referred to as the right side of the expansion valve.

[0017] As shown in FIG. 1, an expansion valve V1 of the present invention, together with a compressor C, an indoor heat exchanger H1, an outdoor heat exchanger H2, and the like, constitutes a refrigeration cycle R used in an air conditioning system for an automobile or the like.

[0018] First, the refrigeration cycle R will be described. In the refrigeration cycle R, during heating, the refrigerant is circulated through the compressor C, the heat exchanger H1, the expansion valve V1, and the heat exchanger H2 in this order. The refrigerant becomes high-temperature, high-pressure superheated vapor by the compressor C, exchanges heat with indoor air by the heat exchanger H1 to become high-temperature, high-pressure supercooled liquid, is reduced in pressure from the high-pressure primary pressure to the low-pressure secondary pressure by the expansion valve V1 to become low-temperature, low-pressure wet vapor, and is heat-exchanged with outdoor air by the heat exchanger H2 to become saturated vapor. As a result, the air in the room is heated by heat exchange with the heat exchanger H1. That is, during heating, the heat exchanger H1 serves as a condenser, and the heat exchanger H2 serves as an evaporator.

[0019] During cooling, the refrigeration cycle R circulates the refrigerant through the compressor C, heat exchanger H2, expansion valve V1, and heat exchanger H1 in that order. The refrigerant becomes high-temperature, high-pressure superheated vapor by the compressor C, exchanges heat with outdoor air by the heat exchanger H2 to become high-temperature, high-pressure supercooled liquid, is reduced in pressure from high-pressure primary pressure to low-pressure secondary pressure by the expansion valve V1 to become low-temperature, low-pressure wet vapor, and is heat-exchanged with indoor air by the heat exchanger H1 to become saturated vapor. As a result, the indoor air is cooled by heat exchange with the heat exchanger H1. That is, during cooling, the heat exchanger H1 serves as an evaporator, and the heat exchanger H2 serves as a condenser.

[0020] In the following description, unless otherwise specified, it is assumed that the refrigeration cycle R is used for heating. Similarly, based on heating, the heat exchanger H1 will be described as a condenser H1, and the heat exchanger H2 will be described as an evaporator H2.

[0021] As shown in Figures 1 and 2, the expansion valve V1 is disposed between the condenser H1 and the evaporator H2. The current flowing through the coil 86 constituting the solenoid 80 is set based on the temperature difference between the refrigerant at the inlet and outlet sides of the evaporator H2. The opening degree of the expansion valve V1 is adjusted according to this current, so that the pressure of the refrigerant passing through the valve 50 is adjusted from the high-pressure primary pressure P1 to the relatively low-pressure secondary pressure P2, and the temperature of the refrigerant is also adjusted from high to low. As a result, all the refrigerant that is a supercooled liquid sent from the condenser H1 is adjusted to the dryness of wet steam that can transition to saturated steam after passing through the evaporator H2.

[0022] In this embodiment, the valve 50 is composed of a valve body 51 and a valve seat 10a formed on the inner surface of the valve housing 10, and the valve 50 opens and closes when the tapered surface portion 51a formed on the axial right end of the valve body 51 moves toward and away from the valve seat 10a.

[0023] Next, the structure of the expansion valve V1 will be described. As shown in Fig. 2, the expansion valve V1 is mainly composed of a valve housing 10 made of a metal material or a resin material, a valve element 51 arranged in the valve housing 10, and a solenoid 80 connected to the valve housing 10 and applying a driving force to the valve element 51.

[0024] As shown in Figures 2 to 4, the valve body 51 has a recess 51b in its center that opens to the right in the axial direction, and the axial left end of the rod 52 that is disposed to penetrate the coil 86 of the solenoid 80 is press-fitted and fixed into the recess 51b. The valve body 51 also has a communication passage 51c that penetrates in the axial direction at a position radially shifted from the recess 51b. The communication passage 51c is formed to have a constant cross section. Note that a plurality of communication passages 51c may be provided, which is preferable because it makes it easier to allow the refrigerant to flow in and out.

[0025] 2 to 4, the valve housing 10 is formed with an outlet port 11 communicating with the evaporator H2 and an inlet port 12 communicating with the condenser H1. The outlet port 11 is formed on the right side of the valve seat 10a in the axial direction, i.e., in the valve closing direction, which will be described later. The inlet port 12 is formed on the left side of the valve seat 10a in the axial direction, i.e., in the valve opening direction, which will be described later.

[0026] The valve housing 10 is provided therein with a primary pressure chamber 14, a secondary pressure chamber 13, a valve orifice portion 15, and a recess 10d. The primary pressure chamber 14 is supplied with refrigerant that has passed through a condenser H1 from an inlet port 12. The secondary pressure chamber 13 is supplied with refrigerant that has passed through a valve 50 from the primary pressure chamber 14, and is output from an outlet port 11. The secondary pressure chamber 13 is also connected to the outlet port 11. The valve orifice portion 15 is disposed between the secondary pressure chamber 13 and the primary pressure chamber 14, and a valve seat 10a is formed on its edge on the left side in the axial direction. The recess 10d is disposed axially to the left of the valve seat 10a, and constitutes the primary pressure chamber 14.

[0027] The opening on the left side in the axial direction of the recess 10d is closed by the cover member 16. Furthermore, a bellows 18 is disposed in the primary pressure chamber 14 as a biasing means for biasing the valve element 51 axially rightward, i.e., in the valve closing direction. The axial left end of the bellows 18 is fixed to the cover member 16 in a sealed manner, and the axial right end is fixed to the axial left end face of the valve element 51 in a sealed manner. That is, the interior of the valve housing 10 is partitioned by the bellows 18, the cover member 16, and the valve element 51 to form a space S1.

[0028] Furthermore, the space S1 communicates with the secondary pressure chamber 13 via the communication passage 51c, and the refrigerant in the secondary pressure chamber 13 flows into the space S1. That is, the bellows 18 divides the space S1 and the primary pressure chamber 14 in a substantially sealed state when the valve 50 is in a closed state.

[0029] Additionally, a flange portion 82d of the center post 82 is inserted from the axial right into a recess 10c that is formed on the axial right end of the valve housing 10 and is recessed axially leftward, so that the center post 82 is connected and fixed integrally in a substantially sealed state to the valve housing 10. A through hole is formed in the bottom of the recess 10c of the valve housing 10, and the recess 10c can be called an annular step.

[0030] As shown in FIG. 2, the solenoid 80 is mainly composed of a casing 81 having an opening 81a that opens to the left in the axial direction, a roughly cylindrical center post 82 that is inserted into opening 81a of the casing 81 from the left in the axial direction and fixed to the inner diameter side of the casing 81, a rod 52 that is inserted into the center post 82 and arranged so as to be able to reciprocate in the axial direction, a valve body 51 that is press-fitted and fixed into the left axial end of the rod 52, a movable iron core 84 into which the right axial end of the rod 52 is inserted and fixed, and an excitation coil 86 that is wound around the outside of the center post 82 via a bobbin.

[0031] The casing 81 has a left end in the axial direction thereof formed with a recess 81b recessed to the right in the axial direction, into which the right end of the valve housing 10 is inserted and fixed in a substantially sealed manner.

[0032] The center post 82 is formed from a rigid body that is a magnetic material such as iron or silicon steel, and includes a cylindrical portion 82b extending axially and having an insertion hole 82c through which the rod 52 is inserted, and an annular flange portion 82d extending radially outward from the outer circumferential surface of the left axial end of the cylindrical portion 82b.

[0033] Furthermore, with the axial right end face of the flange portion 82d of the center post 82 abutting from the axial left against the bottom surface of the recess 81b of the casing 81, the valve housing 10 is inserted into and fixed to the recess 81b of the casing 81 in a substantially sealed manner. In other words, the center post 82 is fixed by sandwiching the flange portion 82d between the bottom surface of the recess 81b of the casing 81 and the bottom surface of the recess 10c of the valve housing 10 from both axial sides.

[0034] Next, the opening and closing operation of the expansion valve V1 will be described.

[0035] First, the de-energized state of the expansion valve V1 will be described. As shown in Figures 2 and 3, in the de-energized state of the expansion valve V1, the valve element 51 is pressed axially rightward, i.e., in the valve closing direction, by the biasing force of the bellows 18, so that the tapered surface portion 51a of the valve element 51 seats on the valve seat 10a, and the valve 50 is closed. More specifically, the tapered surface portion 51a of the valve element 51 comes into contact with and seats on the valve seat 10a, which is tapered so as to widen toward the axial left.

[0036] At this time, the effective pressure receiving area A of the bellows 18, the effective pressure receiving area B of the valve body 51, and the rightward axial direction are positive, and the valve body 51 is subjected to the biasing force (F bel ) and the force due to the primary pressure P1 of the refrigerant (F P1 )=(P1×(AB)) and the force due to the secondary pressure P2 of the refrigerant (F P2 That is, the force F acts on the valve body 51 with the rightward direction being positive. rod =F bel +F P1 -F P2 is at work.

[0037] More specifically, the refrigerant in the space S1 acts on the left axial end face of the valve body 51, and the refrigerant in the secondary pressure chamber 13 acts on the right axial end face of the valve body 51. The secondary pressure chamber 13 and the space S1 are connected by a communication passage 51c formed in the valve body 51, so that the refrigerant in the secondary pressure chamber 13 on the valve closing direction side of the valve body 51, i.e., the refrigerant at secondary pressure P2 supplied from the outlet port 11 to the evaporator H2, flows into the space S1.

[0038] In addition, the left axial end face of the valve body 51 is formed slightly larger than the right axial end face thereof. This makes it easier to maintain the valve 50 in a closed state even if a slight pressure difference occurs momentarily between the pressure in the space S1 and the pressure in the secondary pressure chamber 13.

[0039] Furthermore, since the communicating passage 51c is a narrowed through hole, in other words a through hole with a narrow flow path cross-sectional area, when a slight pressure difference occurs momentarily between the pressure in the space S1 and the pressure in the secondary pressure chamber 13, the refrigerant in the space S1 is unlikely to move momentarily toward the secondary pressure chamber 13 and is instead retained within the space S1, making it easier to maintain the closed state of the valve 50.

[0040] In this way, the refrigerant flowing into the space S1 and the secondary pressure chamber 13 is the same refrigerant with the secondary pressure P2 supplied to the evaporator H2 from the outlet port 11. In addition, since the effective pressure receiving area A of the bellows 18 and the effective pressure receiving area B of the valve body 51 are equal (A=B), the force (F) acting on the valve body 51 due to the refrigerant pressures P1 and P2 is P1 ),(F P2 ) are almost zero. In other words, the rightward direction is positive, and the valve body 51 is substantially subjected to a force F rod =F bel is at work.

[0041] Next, the energized state of the expansion valve V1 will be described. As shown in Fig. 2 and Fig. 4, when the expansion valve V1 is energized, that is, during normal control, or so-called duty control, an electromagnetic force (F sol ) is the force F rod Exceeds (F sol >F rod ), the movable core 84 is attracted toward the center post 82, i.e., to the left in the axial direction, and the rod 52 and valve disc 51 fixed to the movable core 84 move together in the axial left direction, i.e., in the valve opening direction, and the tapered surface portion 51a of the valve disc 51 moves away from the valve seat 10a of the valve housing 10. In this way, the valve 50 is opened. Furthermore, when the solenoid 80 is driven, the movable core 84 comes into contact with the right side of the center post 82 in the axial direction, thereby restricting the valve disc 51 from moving further away from the valve seat 10a.

[0042] At this time, an electromagnetic force (F sol ), and a force F to the right of the axis rod That is, the force F acts on the valve body 51, with the rightward direction being positive. rod -F sol is at work.

[0043] In this way, the valve opening of the expansion valve V1 is adjusted by the balance between the electromagnetic force of the solenoid 80 and the biasing force of the bellows 18. As a result, the refrigerant that has passed through the condenser H1 and is supplied from the inlet port 12 is reduced in pressure from the high-pressure primary pressure P1 to the low-pressure secondary pressure P2 and is supplied to the evaporator H2 via the outlet port 11.

[0044] As described above, the space S1 is formed on the driving direction side of the solenoid 80 from the valve element 51, i.e., on the valve opening direction side of the valve element 51, and the refrigerant in the secondary pressure chamber 13, which has a lower pressure than the refrigerant in the primary pressure chamber 14, flows into this space S1, so that the influence of the pressure difference acting on both sides of the movement direction of the valve element 51 when the valve 50 is changed from the closed state to the open state can be reduced. As a result, the valve element 51 strokes with precision in response to the current value applied to the solenoid 80, so that the valve opening degree by the valve element 51 can be adjusted with high precision. In particular, the expansion valve V1 is configured as a normally closed type in which the valve element 51 is biased in the valve closing direction of the valve 50 by the bellows 18, so that the valve element 51 can be instantly operated to open the valve 50, and the pressure can be quickly reduced from the high pressure primary pressure P1 to the low pressure secondary pressure P2.

[0045] Moreover, since the bellows 18 is disposed in the space S1, there is no need to secure space for arranging a biasing means on the solenoid 80 side, and the expansion valve V1 can be configured compactly. Moreover, since the bellows 18 is disposed on the opposite side of the valve body 51 to the solenoid 80, the operation of the valve body 51 can be stabilized.

[0046] Furthermore, a communication passage 51c that communicates the space S1 and the outlet port 11 is formed in the valve body 51, and the refrigerant at the secondary pressure P2 flows into the space S1 from the outlet port 11 formed in the valve housing 10 through the communication passage 51c. This eliminates the need to form a port separate from the outlet port 11 in the valve housing 10 or the lid member 16, for example, and allows the structure of the expansion valve V1 to be simplified.

[0047] In addition, since the communication passage 51c is formed so as to penetrate the valve body 51 in the axial direction, the processing is simpler than forming a communication passage that connects the space S1 and the outlet port 11 in the valve housing 10.

[0048] Also, since the space S1 and the inlet port 12 are partitioned in a substantially sealed manner by the bellows 18, the refrigerant at the primary pressure P1 is prevented from flowing into the space S1 in the closed state of the valve 50. In other words, since the secondary pressure P2 can be maintained in the space S1 in the closed state of the valve 50, the influence of the differential pressure acting on both sides in the moving direction of the valve body 51 when the valve 50 is changed from the closed state to the open state can be reliably reduced. Further, since the bellows 18 that partitions the space S1 and the inlet port 12 also functions as a biasing means, the expansion valve V1 can have a simple configuration.

[0049] In addition, in the present Example 1, the form in which the effective pressure receiving area A of the bellows 18 and the effective pressure receiving area B of the valve body 51 are the same (A = B) is illustrated. However, the effective pressure receiving area A may be slightly larger than the effective pressure receiving area B (A > B) so as to surely maintain the closed state of the valve 50, or the effective pressure receiving area B may be slightly larger than the effective pressure receiving area A (A < B) to facilitate opening of the valve 50. That is, it is sufficient that the influence of the pressure of the refrigerant acting on both sides in the moving direction of the valve body 51 is small.

[0050] In addition, in the present Example 1, the form in which the bellows 18 has both the function of partitioning the space S1 and the primary pressure chamber 14 and the function as a biasing means is illustrated. However, if there is a separate biasing means for biasing the valve body 51 in the valve closing direction, the bellows 18 does not have to have a biasing force.

Example

[0051] The expansion valve according to Example 2 will be described with reference to FIGS. 5 to 7. In addition, the description of the same configuration as that of the above Example 1 will be omitted.

[0052] 5 and 6, in the expansion valve V2 of the second embodiment, the valve body 151 of the valve 150 is a cylindrical body having a through hole 151b formed in the center thereof, and an edge portion of the right axial end 151a is seated on the valve seat 10a. The left axial end of the rod 52 is press-fitted and fixed in a state in which it passes through the through hole 151b.

[0053] The left and right axial end faces of the valve body 151 are formed to have the same diameter. In other words, an effective pressure-receiving area A' of the valve body 151 on which the refrigerant in the space S2 (described later) acts is equal to an effective pressure-receiving area B' of the valve body 151 on which the refrigerant in the secondary pressure chamber 13 acts (A'=B').

[0054] A space S2 is formed inside the valve housing 10, which is partitioned by the recess 10d, the cover member 161, and the valve body 151. The valve housing 10 also has an annular portion extending radially inward between the recess 10d and the inlet port 12. The inner circumferential surface of the annular portion functions as a guide surface 10b along which the outer circumferential surface of the valve body 151 can slide in a substantially sealed state.

[0055] A minute gap is formed between the guide surface 10b and the outer peripheral surface of the valve body 151 by being slightly separated in the radial direction, allowing the valve body 151 to move smoothly in the axial direction relative to the valve housing 10, and the gap functions as a clearance seal that partitions the space S2 and the primary pressure chamber 14 in an approximately hermetic manner.

[0056] The secondary pressure chamber 13 and the space S2 are in communication with each other through a communication passage 151c formed in the valve body 151. That is, the refrigerant in the secondary pressure chamber 13 flows into the space S2 through the communication passage 151c. A spring 17 is disposed in the space S2 as a biasing means for biasing the valve body 151 axially rightward.

[0057] Next, the opening and closing operation of the expansion valve V2 will be described.

[0058] First, the de-energized state of the expansion valve V2 will be described. As shown in Figures 5 and 6, in the de-energized state of the expansion valve V2, the valve element 151 is pressed axially rightward by the biasing force of the spring 17, so that the axial right end 151a of the valve element 151 is seated on the valve seat 10a, and the valve 150 is closed.

[0059] At this time, the valve body 151 is subjected to the biasing force (F sp ) and the pressure of the refrigerant against the left end face of the valve body 151 in the axial direction (F P1 ) acts on the right side surface of the valve body 151 in the axial direction toward the left, and the refrigerant pressure (F P2 That is, the force F acts on the valve body 151, with the rightward direction being positive. rod =F sp +F P1 -F P2 is at work.

[0060] In detail, since the effective pressure receiving areas A' and B' of the valve body 151 are equal (A'=B'), the force (F P1 ),(F P2 ) are almost zero. In other words, the rightward direction is positive, and the valve body 51 is substantially subjected to a force F rod =F sp is at work.

[0061] Next, the energized state of the expansion valve V2 will be described. As shown in Fig. 5 and Fig. 7, when the expansion valve V2 is energized, that is, during normal control, or so-called duty control, an electromagnetic force (F sol ) is the force F rod Exceeds (F sol >F rod), the movable core 84 is attracted toward the center post 82, i.e., to the left in the axial direction, and the rod 52 and valve body 151 fixed to the movable core 84 move together in the axial left direction, and the right axial end 151a of the valve body 151 moves away from the valve seat 10a of the valve housing 10. In this manner, the valve 150 is opened. When the solenoid 80 is driven, the movable core 84 comes into contact with the right side of the center post 82 in the axial direction, thereby restricting the valve body 151 from moving further away from the valve seat 10a. The left axial end of the rod 52 may come into contact with a shaft portion protruding to the right from the cover member 16 to restrict the movement of the valve body 151.

[0062] In this way, refrigerant from the secondary pressure chamber 13 on the closing side of the valve body 151 flows into the space S2 formed on the opening side of the valve body 151, so that the pressure difference on both sides of the movement direction of the valve body 151 is small, and the valve opening degree can be adjusted by the valve body 151 with high precision.

[0063] Furthermore, the valve housing 10 is formed with a guide surface 10b that guides the movement of the valve element 151, and the space S2 and the inlet port 12 are partitioned in a substantially sealed manner by a clearance seal formed between the guide surface 10b and the outer circumferential surface of the valve element 151, so that it is possible to prevent refrigerant at the primary pressure P1 from flowing into the space S2 when the valve 150 is in the closed state. In other words, it is easy to retain refrigerant at the secondary pressure P2 in the space S2, so that it is possible to reliably reduce the differential pressure acting on the valve element 151 when the valve 150 is changed from the closed state to the open state.

[0064] In addition, since the space S2 and the inlet port 12 are partitioned in an approximately sealed manner by a clearance seal formed between the guide surface 10b and the outer peripheral surface of the valve body 151, there is no need to prepare a separate component for partitioning the space S2 and the inlet port 12, reducing the number of parts and simplifying the structure of the expansion valve V2.

[0065] Furthermore, the valve housing 10 is formed with a guide surface 10b through which the valve element 151 is inserted, so that the valve element 151 is guided along the guide surface 10b. This improves the accuracy of the movement of the valve element 151. Furthermore, the valve seat 10a and the guide surface 10b are integrally formed in the valve housing 10, so that a compact expansion valve V2 with a reduced number of parts can be provided.

[0066] In addition, since the effective pressure receiving areas A' and B' of the valve body 151 are the same, the refrigerant pressure (F P1 ) and refrigerant pressure (F P2 In other words, the secondary pressure P2 acting on the valve body 151 from both sides in the driving direction of the solenoid 80 is canceled, so the operation of the solenoid 80 is not affected by the secondary pressure P2. The valve opening is controlled by the electromagnetic force (F sol ) and the biasing force of spring 17 (F sp ) is adjusted by balancing the flow rate of the refrigerant sent to the evaporator H2. EXAMPLES

[0067] An expansion valve according to a third embodiment will be described with reference to Fig. 8. Note that a description of the same configuration as in the first embodiment will be omitted.

[0068] As shown in FIG. 8, in a valve housing 100 of the third embodiment, an outlet port 111 is formed axially to the left of the valve seat 10a, and an inlet port 121 is formed axially to the right of the valve seat 10a.

[0069] When the expansion valve V3 is in a non-energized state, i.e., in a closed state, refrigerant at a primary pressure P1 that has passed through the condenser H1 flows into the primary pressure chamber 141 that is connected to the inlet port 121, and the refrigerant in the primary pressure chamber 141 flows into the space S3 through the connecting passage 51c.

[0070] In this way, refrigerant from the primary pressure chamber 141 on the closing side of the valve body 151 flows into the space S3 formed on the opening side of the valve body 51, thereby reducing the pressure difference on both sides of the movement direction of the valve body 51, and enabling the valve opening degree to be adjusted by the valve body 51 with high precision. EXAMPLES

[0071] An expansion valve according to a fourth embodiment will be described with reference to Fig. 9. Note that a description of the same configuration as in the first embodiment will be omitted.

[0072] 9, the valve body 251 of the fourth embodiment has a recess 251b in its center that opens to the axial right, and a spring 19 is disposed in the recess 251b to urge the rod 252, which is disposed to pass through the coil 86 of the solenoid 80, to the axial right. The spring 19 has its left axial end in contact with the bottom surface of the recess 251b, and its right axial end in contact with the left axial side surface of a flange portion 252a extending radially outward from the outer circumferential surface of the left axial end portion of the rod 252.

[0073] When the expansion valve V4 is in a non-energized state, that is, in a closed state, the spring 19 supports the bottom surface of the recess 251b and the left axial end of the rod 252 in a state separated from each other in the axial direction.

[0074] In addition, in the expansion valve V4, when current is applied to the solenoid 80, an electromagnetic force (F sol ) is the biasing force of the spring 19 (F sp2 ) exceeds (F sol >F sp2 ), the movable core 84 is attracted toward the center post 82, i.e., toward the left in the axial direction, and the rod 252 fixed to the movable core 84 moves leftward in the axial direction, so that the left end of the rod 252 in the axial direction comes into contact with the bottom surface of the recess 251b. sol ) is the biasing force of the spring 19 (F sp2 ) and the biasing force of the bellows 18 (F bel ) exceeds (F sol >F sp2 +F bel), the movable core 84 is drawn further toward the center post 82, and the rod 252 fixed to the movable core 84 and the valve body 251 in contact with the rod 252 move together in the axial leftward, i.e., in the valve-opening direction, and the tapered surface portion 51a of the valve body 251 moves away from the valve seat 10a of the valve housing 10. In this manner, the valve 50 is opened.

[0075] In this way, the valve element 251 and the rod 252 are not fastened together, but are supported by the spring 19 in a state of being spaced apart in the axial direction, which can improve the vibration resistance of the valve element 251 and the rod 252. In more detail, even if vibration occurs in the rod 252 that constitutes the solenoid 80 due to disturbance or the like, the vibration is absorbed by the spring 19 and transmission of the vibration to the valve element 251 is suppressed, so that the closed state of the expansion valve V4 is stabilized, sealing performance is improved, and valve leakage can be reduced. EXAMPLES

[0076] An expansion valve according to a fifth embodiment will be described with reference to Fig. 10. Note that a description of the same configuration as in the first embodiment will be omitted.

[0077] 10, the valve body 51 of the fifth embodiment has a recess 51b in its center that opens axially rightward, and the left axial end of the rod 352 that is disposed to penetrate through the coil 86 of the solenoid 80 is inserted into the recess 51b. The left axial end of the rod 352 is formed into a substantially hemispherical surface and is in point contact with the bottom surface of the recess 51b.

[0078] In this way, by not fastening the valve body 51 and the rod 352, and by making the left axial end of the rod 352, which is formed into an approximately hemispherical surface, into point contact with the bottom surface of the recess 51b, even if the rod 352 or the valve body 51 tilts, there is no need to correct the tilt during operation, as would be the case if there was surface contact.This prevents the movable core 84 or rod 352 from tilting, and suppresses an increase in the sliding resistance between them and the components of the solenoid 80, thereby minimizing the impact on the operability of the expansion valve V5. EXAMPLES

[0079] An expansion valve according to a sixth embodiment will be described with reference to Fig. 11. Note that a description of the same configuration as that of the first embodiment will be omitted.

[0080] As shown in FIG. 11, the valve body 451 of the sixth embodiment has an axial right end face formed into an approximately hemispherical surface, and the axial left end of the rod 52 that is arranged to pass through the coil 86 of the solenoid 80 is in point contact with the center of the right end face.

[0081] In this way, by not fastening the valve body 451 and the rod 52, and by making the left axial end of the rod 52 make point contact with the center of the left axial end face of the valve body 451, which is formed into an approximately hemispherical surface, even if the rod 52 or the valve body 451 tilts, there is no correction of the tilt during operation, which would be the case if there was surface contact. This prevents the movable iron core 84 or rod 52 from tilting, and suppresses an increase in the sliding resistance between them and the components of the solenoid 80, thereby minimizing the impact on the operability of the expansion valve V6.

[0082] Furthermore, when the expansion valve V6 is de-energized, i.e., when the valve 50 is closed, the valve element 451 is pressed axially rightward, i.e., in the valve closing direction, by the biasing force of the bellows 18, so that the outer diameter portion 451a of the axial right end face of the valve element 451, which is formed into a substantially hemispherical surface, is seated on the valve seat 10a. As a result, even if the valve element 451 is tilted, the outer diameter portion 451a is reliably seated on the valve seat 10a, thereby improving sealing performance and reducing valve leakage.

[0083] Furthermore, as long as the axial right end face of the valve body 451 is formed as part of a spherical surface near the center where the axial left end of the rod 52 contacts, the portion of the valve body 451 that seats on the valve seat 10a may be formed by a tapered surface portion 51a, for example, as in the first embodiment. EXAMPLES

[0084] An expansion valve according to a seventh embodiment will be described with reference to Fig. 12. Note that a description of the same configuration as that of the first embodiment will be omitted.

[0085] As shown in FIG. 12, the valve body 551 of the seventh embodiment is formed by a steel ball that is fixed by crimping or press-fitting into a recess 552b that opens to the right in the axial direction of an adapter 552 to which the right axial end of the bellows 18 is hermetically fixed, and the left axial end of the rod 52 that is arranged to pass through the coil 86 of the solenoid 80 is in point contact with the spherical surface of the valve body 551 that is arranged in the secondary pressure chamber 13.

[0086] A communication passage 516a is formed in the lid member 516, which is fixed in a sealed manner to the left axial end of the bellows 18, and passes through in the axial direction. The communication passage 516a communicates with the evaporator H2 via an orifice (not shown) provided outside the expansion valve V7. That is, the refrigerant at the secondary pressure P2 supplied from the outlet port 11 to the evaporator H2 flows into the space S1 formed inside the bellows 18.

[0087] In this way, the expansion valve V7 has a space S1 formed on the side of the driving direction of the solenoid 80 from the valve element 551, i.e., on the valve opening direction side of the valve element 551. The refrigerant in the secondary pressure chamber 13, which has a lower pressure than the refrigerant in the primary pressure chamber 14, flows into this space S1 through an orifice (not shown) formed outside the expansion valve V7 and a communication passage 516a formed in the lid member 516. With this, when the valve 50 is changed from the closed state to the open state, the influence of the differential pressure acting on both sides in the moving direction of the valve element 551 is small, and the valve element 551 strokes with high accuracy in response to the current value applied to the solenoid 80. In this way, the valve opening degree can be adjusted with high accuracy by the valve element 551.

[0088] Furthermore, by not fastening the valve body 551 and the rod 52, and by making the left axial end of the rod 52 make point contact with the spherical surface of the valve body 551 located in the secondary pressure chamber 13, even if the rod 52 or the valve body 551 tilts, there is no need to correct the tilt during operation, as would be the case if there was surface contact. This prevents the movable iron core 84 or rod 52 from tilting, and suppresses an increase in the sliding resistance between these and the components of the solenoid 80, thereby minimizing the impact on the operability of the expansion valve V7.

[0089] Furthermore, when the expansion valve V7 is de-energized, i.e., when the valve 50 is closed, the valve element 551 is pressed axially rightward, i.e., in the valve closing direction, by the biasing force of the bellows 18, so that the spherical portion 551a of the valve element 551 seats on the valve seat 10a. As a result, even if the valve element 551 is tilted, the spherical portion 551a seats reliably on the valve seat 10a, improving sealing performance and reducing valve leakage.

[0090] Furthermore, by using a steel ball as the valve body 551, it is possible to provide a structure that is resistant to mechanical wear.

[0091] Although the embodiments of the present invention have been described above with reference to the drawings, the specific configuration is not limited to these embodiments, and the present invention also includes modifications and additions that do not deviate from the gist of the present invention.

[0092] For example, in the above-mentioned first to third embodiments, the valve body is configured as a separate member from the rod that is disposed to pass through the coil of the solenoid, but the present invention is not limited to this, and the valve body and the rod may be configured as one unit.

[0093] In addition, in the first to seventh embodiments, the valve seat is formed integrally with the valve housing, but the valve seat may be separate from the valve housing.

[0094] In addition, in the second embodiment, the valve seat and the guide surface are integrally formed on the inner circumferential surface of the valve housing. However, the present invention is not limited to this. The valve housing having the valve seat and the valve housing having the guide surface may be provided separately.

[0095] Furthermore, the guide surface is not limited to being formed on the valve housing, but may be formed, for example, on a part of the insertion hole of the center post.

[0096] In addition, in the above-described first to seventh embodiments, the biasing means is disposed in the space on the valve opening direction side of the valve body, but the biasing means may be disposed in a location other than the space on the valve opening direction side of the valve body, such as on the solenoid side.

[0097] In addition, in the above-mentioned Examples 1, 2, and 4 to 6, the space and the outlet port are connected to each other through a communication passage formed in the valve body, but the present invention is not limited to this, and the communication passage may be formed in the valve housing. Also, the communication passage may be omitted, and a separate port that communicates with the evaporator may be formed in the valve housing that defines the space or in the cover member as in the above-mentioned Example 7. [Explanation of symbols]

[0098] 10 Valve housing 10a Valve seat 10b Guide surface 11 Exit Port 12 Inlet Port 13 Secondary pressure chamber 14 Primary pressure chamber 17 Spring (biasing means) 18 Bellows (biasing means) 50 valves 51 Valve body 51c Communication path 80 Solenoid 100 Valve housing 150 valves 151 Valve body 151c Communication path 251 Valve body 252 Rod 252a Flange part 352 Rod 451 Valve body 516 Lid member 516a Communication path 551 Valve body 552 Adapter A,B Effective pressure area A',B' Effective pressure receiving area C Compressor H1 Heat exchanger (condenser) H2 heat exchanger (evaporator) R Refrigeration cycle S1~S3 space V1~V7 Expansion valve

Claims

1. a valve housing having an inlet port through which a refrigerant from a condenser passes and an outlet port through which a refrigerant to an evaporator passes; A valve body actuated by a solenoid; a valve seat on which the valve body is seated; and a biasing means for biasing the valve body in a valve closing direction. the outlet port is provided on the valve closing direction side of the valve seat, A space separated from the inlet port is formed on the valve opening direction side of the valve body, An expansion valve having a communication passage that communicates between the space and the outlet port.

2. 2. The expansion valve according to claim 1, wherein the biasing means is disposed in the space.

3. 3. The expansion valve according to claim 1, wherein the communication passage is formed in the valve body.

4. 4. An expansion valve according to claim 1, wherein the space and the inlet port are partitioned by a bellows.

5. 5. The expansion valve according to claim 4, wherein an effective pressure-receiving area of ​​said valve body is equal to an effective pressure-receiving area of ​​said bellows.

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