CN115013575A

CN115013575A - Pressure regulating valve

Info

Publication number: CN115013575A
Application number: CN202210145955.0A
Authority: CN
Inventors: 当山雄一郎
Original assignee: Saginomiya Seisakusho Inc
Current assignee: Saginomiya Seisakusho Inc
Priority date: 2021-03-03
Filing date: 2022-02-17
Publication date: 2022-09-06
Also published as: JP2022134450A; JP7406518B2

Abstract

The invention provides a pressure regulating valve having a regulating spring and a pressure-sensitive member, which can reduce sliding resistance and hysteresis by suppressing a side force generated by the regulating spring. A pressure regulating valve (100a) is provided with: a valve body (5) having a valve seat (18); a valve needle (30) having a valve portion (32) that can be brought into contact with and separated from a valve seat (18); a pressure-sensitive unit (40) that is flexible in the axial direction and that has a pressure-sensitive member (41) that biases the valve section (32); an adjustment spring unit (50) having an adjustment spring (53) that biases the valve unit (32) in the valve closing direction; and a connecting mechanism (70) which forms a concave-convex engagement with a centripetal action between the pressure-sensitive unit (40) and the adjusting spring unit (50), wherein the adjusting spring (53) is a wave spring. Since the wave spring suppresses the lateral force, the sliding resistance can be reduced, and the hysteresis can be reduced.

Description

Pressure regulating valve

Technical Field

The present invention relates to a pressure regulating valve including a regulating spring and a pressure sensitive member.

Background

In the pressure regulating valve: the valve opening degree is controlled according to the pressure variation by providing the adjusting spring and the pressure-sensitive member.

For example, fig. 6 shows a pressure regulating valve (hereinafter, referred to as a "conventional pressure regulating valve") using a coil spring and a pressure-sensitive bellows as a regulating spring and a pressure-sensitive member, respectively. In the conventional pressure regulating valve 300, an inlet pipe 301 and an outlet pipe 302 are connected to a valve housing 310, and a ball valve 330 that can be brought into contact with and separated from a valve seat 318 is provided in a valve chamber 311 that communicates the above components. The conventional pressure regulating valve 300 includes a pressure-sensitive unit 340 and an adjusting spring unit 350 that bias the ball valve 330 in a closing direction, and a flow regulating element unit 390 that biases the ball valve 330 in an opening direction (see patent document 1). Here, the pressure-sensitive unit 340 is composed of a pressure-sensitive bellows 341, a bellows lower cover 342, a bellows upper cover 343, and a coupling rod 345. The adjustment spring unit 350 is composed of a spring holder member 351, an adjustment screw member 352, and an adjustment spring 353 sandwiched between the spring holder member 351 and the adjustment screw member 352.

Documents of the prior art

Patent document

Patent document 1: japanese laid-open patent publication No. 6-229481

Disclosure of Invention

Problems to be solved by the invention

First, the pressure-sensitive unit 340 and the adjustment spring unit 350 are engaged with each other via the coupling rod 345. One end and the other end of the connecting rod 345 are fitted to the bellows lower cover 342 and the spring bearing member 351, which are movable in the radial direction, via a first guide vane 346 and a second guide vane 355, respectively, which are elastic members. The center portion of the connecting rod 345 is inserted into an insertion hole 343a provided in the bellows upper cover 343, but a slight gap is provided between the connecting rod 345 and the insertion hole 343 a. Through the minute gap, the atmospheric pressure is introduced into the internal space of the pressure sensitive bellows 341, and the secondary pressure P2 is introduced into the external space of the pressure sensitive bellows 341. Further, the rectifying element unit 390 transmits the urging force of the coil spring 392 to the ball valve 330 via the rectifying element 391.

Here, the conventional pressure regulating valve 300 employs a coil spring as the regulating spring 353. When this coil spring is compressed, the inclination angle of the wound wire material does not change uniformly over all, and therefore the center axis of the coil spring is inclined, and a large amount of force (lateral force) is generated that does not follow the center axis C.

Therefore, even when the coil spring is assembled with high accuracy in the conventional pressure regulating valve 300, a lateral force generated by the coil spring is transmitted to the connecting rod 345 during compression, and the connecting rod 345 slides relative to the insertion hole 343a in a state of being inclined relative to the central axis C. This causes a problem of an increase in the sliding resistance between the connecting rod 345 and the insertion hole 343a (hereinafter referred to as "conventional problem (increase in sliding resistance)"), and the hysteresis increases.

The present invention aims to provide a pressure regulating valve including a regulating spring and a pressure-sensitive member, which can reduce sliding resistance and hysteresis by suppressing a lateral force generated by the regulating spring.

Means for solving the problems

In order to solve the above problem, a pressure regulating valve includes: a valve body having a valve seat; a valve needle having a valve portion that can be brought into contact with and separated from the valve seat; a pressure-sensitive unit having a pressure-sensitive member that is deflected in an axial direction and that biases the valve portion; an adjustment spring unit having an adjustment spring for urging the valve portion in a valve closing direction via the pressure-sensitive member; and a connection mechanism for forming a concave-convex engagement with a centripetal action between the pressure-sensitive unit and the adjustment spring unit, wherein the adjustment spring is a wave spring.

The pressure regulating valve may be configured such that the regulating spring unit further includes a spring receiver member having a convex portion and a regulating screw member having a concave portion, the needle side and the regulating spring unit side of the wave spring are supported by the convex portion and the concave portion, respectively, and the spring receiver member is relatively rotatable with respect to the pressure-sensitive unit via the coupling mechanism.

The pressure regulating valve may be configured such that a static friction force generated between the needle side of the wave spring and the spring receiving member is set to be larger than a static friction force generated between the spring receiving member and the coupling mechanism.

The pressure regulating valve may be configured such that flat annular seat portions are provided at both end portions of the wave spring.

The pressure regulating valve may be configured such that a range of use of the wave spring is set so as to avoid a spring constant inflection point so that the wave spring has a linear characteristic from a closed state to a fully open state of the valve portion.

The pressure regulating valve may be configured such that the wave spring is housed in a spring case of the valve main body that is separated from the control fluid.

The pressure regulating valve may be configured to use carbon dioxide as the control fluid.

The pressure-regulating valve may be configured such that the pressure-sensitive unit further includes a cover on the adjustment spring unit side having a cylindrical sliding portion communicating in the axial direction, and the connection mechanism includes a connection member having a circular side portion when viewed in the axial direction, and the side portion of the connection member is in point contact with the sliding portion.

Further, the pressure regulating valve may be configured such that the pressure-sensitive cell further includes: a connecting rod, an end of the connecting rod on the side of the adjusting spring unit being disposed so as to be insertable into the sliding portion; and the pressure-sensitive member formed of a pressure-sensitive bellows, an end portion of the pressure-sensitive bellows on the needle side being connected to the connecting rod, and an end portion of the pressure-sensitive bellows on the adjustment spring unit side being fixed so as not to be relatively displaceable with respect to the valve body, wherein the connection mechanism further includes an engagement portion provided in an axial center portion of the end portion of the adjustment spring unit on the needle side, and the engagement portion and the connection member have a shape recessed toward the adjustment spring unit side and a shape protruding therefrom, and form a concave-convex engagement.

The effects of the invention are as follows.

According to the present invention, it is possible to provide a pressure regulating valve including a regulating spring and a pressure-sensitive member, which can reduce sliding resistance and hysteresis by suppressing a lateral force generated by the regulating spring.

Drawings

Fig. 1 is a cross-sectional view showing a closed state of a pressure regulating valve according to a first embodiment of the present invention, where (a) shows an entire view of the pressure regulating valve, and (b) shows an enlarged view of a region surrounded by a broken line Ib in (a).

Fig. 2 is a perspective view illustrating an external appearance of the wave spring of fig. 1.

FIG. 3 is a load-deflection graph illustrating the non-linear characteristics of the wave spring of FIG. 2.

Fig. 4 is a partially enlarged view of an upper connection mechanism of the pressure regulating valve according to the modification of the first embodiment.

Fig. 5 is a sectional view showing a closed state of the pressure regulating valve according to the second embodiment.

Fig. 6 is a cross-sectional view showing a closed state of a pressure regulating valve including a regulating spring and a pressure sensitive member according to the related art.

Description of the symbols

100a, 100b, 200-pressure regulating valve, 5, 205-valve body, 10, 210-valve housing, 11, 211-inlet port, 12, 212-outlet port, 15-valve chamber, 16-bellows housing chamber, 18-valve seat, 20-spring housing, 30-valve needle (valve core), 40, 240-pressure-sensitive unit, 41-pressure-sensitive bellows (pressure-sensitive member), 43, 143-bellows upper cover (cover on the side of the pressure-sensitive spring unit), 43 a-insertion hole, 43 c-sliding portion, 45, 245-connecting rod, 50-regulating spring unit, 51-spring holder member, 51 a-boss portion (convex portion), 51 b-flange portion (convex portion), 52-regulating screw member, 52 a-annular wall portion (concave portion), 52 b-upper surface portion (concave portion), 53-regulating spring (wave spring), 53 c-peak portion, 53 d-lower end portion, 53 s-separating portion, 53sd — lower seat, 53st — step, 53su — upper seat, 53 u-upper end, 53 t-contact, 53 v-valley, 60-lower connection, 63-ball, 70, 170, 270-upper connection (connection), 71, 271-lower engagement, 72-upper engagement, 73b, 173 b-connection, 241-pressure-sensitive diaphragm (pressure-sensitive part), 242-diaphragm lower cover, 243-diaphragm upper cover (cover on the side of adjusting spring unit), 244-pressure plate, C-center axis, L1, L2-maximum valve lift.

Detailed Description

Embodiments of the present invention will be described in detail with reference to fig. 1 to 5. However, the present invention is not limited to the embodiment of the present embodiment.

(related to terminology)

In the description of the present specification, "upper" and "lower" indicate "the adjustment spring unit side" and "the needle side". In the description of the present specification and claims, "one end" and "the other end" indicate a "needle side" and an "adjustment spring unit side". In the present specification and claims, the "effective pressure receiving area of the pressure-sensitive bellows" indicates a pressure receiving area as an approximate value calculated based on the average inner diameters of the minimum inner diameter (the inner diameter of the "valley" portion in the bellows shape protruding toward the central axis side of the pressure-sensitive bellows) and the maximum inner diameter (the inner diameter of the "peak" portion of the bellows shape protruding in the direction away from the central axis of the central axis side of the pressure-sensitive bellows) of the bellows shape. In the description of the present specification and claims, "guidable" means a case including "slidable". In the description and claims of the present specification, "concave-convex engagement" indicates a case where a shape recessed in the axial direction and a shape protruding therefrom are engaged with each other.

(first embodiment)

Structure of pressure regulating valve

A pressure regulating valve 100a according to a first embodiment of the present invention will be described with reference to fig. 1. The pressure regulating valve 100a is mainly composed of a valve main body 5, a needle (valve body) 30, a pressure-sensitive unit 40, and an adjusting spring unit 50. Hereinafter, the respective configurations of the pressure regulating valve 100a will be described in order with the lower connection mechanism 60 and the upper connection mechanism (connection mechanism) 70 added. The pressure regulating valve 100a is assembled to the valve main body 5 in a state of being indirectly engaged from one end side to the other end side in the order of the needle 30, the pressure-sensitive unit 40, and the adjusting spring unit 50. Here, the pressure regulating valve 100a of the present embodiment employs a wave spring as the regulating spring 53, but this will be described in detail below. In this wave spring, a plurality of contact portions 53t (see fig. 2) formed in the circumferential direction are arranged in a staggered manner in the spring center axis direction. Therefore, in the pressure regulating valve 100a of the present embodiment, the plurality of contact portions 53t always serve as fulcrums when the wave spring is compressed, and since the urging force is reliably transmitted along the center axis C and the lateral force is suppressed, the conventional problem (increase in sliding resistance) can be solved and the hysteresis can be reduced.

The valve main body 5 includes a valve housing 10 connected to the inlet pipe 1 and the outlet pipe 2, and a spring housing 20 coupled to the other end of the valve housing 10 by caulking or the like. The valve body 5 is made of a suitable material such as a metal such as brass, iron, aluminum, or stainless steel, or a resin material such as polyphenylene sulfide (PPS).

The valve housing 10 is a hollow cylindrical member, and has a through hole penetrating along the center axis C, and an inlet port 11, a needle guide hole 13, a needle housing chamber 14, a valve chamber 15, and a bellows housing chamber 16 connected to the inflow pipe 1 are provided in the through hole so as to communicate with each other. The needle guide hole 13 is set to have a smaller inner diameter than the needle housing chamber 14, and an annular step portion 17 is provided at a connection portion between the needle guide hole 13 and the needle housing chamber 14. The valve chamber 15 is set to have a larger inner diameter than the needle housing chamber 14, and an annular valve seat 18 is provided at a connection portion between the valve chamber 15 and the needle housing chamber 14.

The valve housing 10 also has a through hole radially penetrating from the valve chamber 15, and the through hole is provided with an outlet port 12 connected to the outlet pipe 2. Thus, in the valve closed state, the secondary pressure P2 can be introduced into the valve chamber 15 and the bellows housing chamber 16 via the outlet port 12.

The spring housing 20 is a hollow cylindrical member having a through hole penetrating along the center axis C, and is provided with a spring housing chamber 21. Further, a female screw portion 22 is provided on the inner peripheral side of the other end portion of the spring housing 20, and is screwed to a male screw portion 52c provided on the outer peripheral side of the adjustment screw member 52 so as to be movable in the axial direction. The atmosphere is always introduced into the spring housing chamber 21 through the screw joint.

Next, the needle 30 will be explained. The needle 30 includes a cylindrical guide portion 31 extending toward one end in the axial direction, a substantially truncated cone-shaped valve portion 32 provided on the other end, and an annular spring support portion 33 provided between the guide portion 31 and the valve portion 32. The needle 30 has an internal flow path 34 that extends along the center axis C in the guide portion 31 and penetrates the other end side of the guide portion 31 in the radial direction. The needle 30 is made of metal such as stainless steel.

The guide portion 31 of the needle 30 is disposed so as to be axially guided in the needle guide hole 13 of the valve housing 10. Here, the clearance formed between the outer diameter of the guide portion 31 and the inner diameter of the needle guide hole 13 is set to be small, and strict tolerance control is performed. The needle 30 is constantly biased in the valve opening direction by the valve spring 6 sandwiched between the spring support portion 33 of the needle 30 and the step portion 17 of the valve housing 10. Thus, the needle 30 is guided in a stable state in the axial direction, and the center position of the needle 30 and the center position of the seat 18 are always matched when viewed from the direction of the center axis C, so that flow rate instability and valve leakage can be improved.

The movement of the needle 30 in the axial direction is generated by a pressure difference between the primary pressure P1 and the secondary pressure P2, the urging force of the pressure-sensitive bellows 41 and the adjustment spring 53 acting on the other end portion of the valve portion 32, the urging force of the valve spring 6 acting on the spring support portion 33, and the like, which will be described in detail later. The valve portion 32 is movable in contact with and away from the valve seat 18 by the external force, and determines the valve opening degree. Here, the step portion 45c of the connecting rod 45 is brought into contact with the bellows upper cover 43, whereby the maximum valve lift amount L1 from the valve-closed state to the valve fully-opened state that is the maximum valve lift state of the needle 30 is defined. In the pressure regulating valve 100a of the present embodiment, unlike the fully opened valve state in which the maximum valve lift state is achieved, there is a fully opened valve state in which the valve is opened by a predetermined flow rate before the stepped portion 45c of the connecting rod 45 comes into contact with the bellows upper cover 43.

Next, the pressure-sensitive unit 40 will be explained. The pressure-sensitive unit 40 is constituted by a pressure-sensitive bellows (pressure-sensitive member) 41, a bellows upper cover (cover on the adjustment spring unit side) 43, and a coupling rod 45 having one end and the other end extending along the center axis C. One end and the other end of the pressure-sensitive bellows 41 extending along the center axis C are connected to one end of the connection rod 45 and the bellows upper cover 43, respectively, and the valve portion 32 is biased in the valve closing direction. The pressure-sensitive unit 40 is made of metal such as stainless steel, and is accommodated in the bellows accommodation chamber 16 of the valve housing 10.

The pressure-sensitive bellows 41 is connected to one end of the connection rod 45 and the bellows upper cover 43, respectively, so that the secondary pressure P2 is always introduced into the external space of the pressure-sensitive bellows 41 through the valve chamber 15 and the bellows housing chamber 16. On the other hand, the atmosphere is always introduced into the internal space of the pressure-sensitive bellows 41 through the gap formed between the small-diameter portion 45b of the connecting rod 45 and the insertion hole 43a of the bellows upper cover 43 and the gap formed between the connecting member 73b and the sliding portion 43c of the bellows upper cover 43. In the bellows 41 for pressure sensing, the dimensional relationship of the respective portions is set so that the outer diameter of the crest portions and the inner diameter of the trough portions in the bellows shape are always in a non-contact state with the valve housing 10 and the connecting rod 45.

The connecting rod 45 includes a substantially cylindrical large diameter portion 45a extending toward one axial end side and a substantially cylindrical small diameter portion 45b extending from the large diameter portion 45a toward the other axial end side. A flange portion 45d that protrudes in the radial direction and connects one end portion of the pressure-sensitive bellows 41 is formed at one end portion of the large-diameter portion 45 a. An annular step portion 45c is formed between the large diameter portion 45a and the small diameter portion 45 b.

The bellows upper cover 43 includes: an insertion hole 43a extending concentrically along the center axis C and through which the small diameter portion 45b of the connecting rod 45 is inserted; a bellows upper cover joint portion 43b to which the other end portion of the pressure-sensitive bellows 41 is connected; and a cylindrical sliding portion 43C extending concentrically along the center axis C, having an inner diameter larger than that of the insertion hole 43a, for inserting the small diameter portion 45b of the connecting rod 45, and for sliding the connecting member 73 b. Here, the pressure-sensitive unit 40 is fixed relative to the valve main body 5 via the welded portion w so as not to be relatively displaceable. The weld w shows an area where the bellows upper cover 43 and the other end portion of the valve housing 10 are welded to each other. By adjusting the position of the welded portion w in the axial direction, it is possible to absorb individual differences in the length of the pressure-sensitive unit 40, assembly errors in the valve body 5, and the like.

In the present embodiment, the one end side of the pressure-sensitive unit 40 is configured to connect the pressure-sensitive bellows 41 to the flange 45d of the connection rod 45, but the present invention is not limited thereto. For example, the pressure-sensitive bellows 41 having the lower end portion in the shape of a cap or the bellows lower cover in the form of separating the flange portion 45d from the one end portion of the connection rod 45 may be used, and the flange portion 45d may be omitted from the connection rod 45 and the one end portion of the connection rod 45 may be connected to the lower end portion in the shape of a cap or the bellows lower cover. Further, the inclination of the connection rod 45 with respect to the center axis C and the asymmetry of the pressure-sensitive bellows 41 can be absorbed by the connection form in which one end of the connection rod 45 is movable in the radial direction with respect to the lower end of the capped shape or the bellows lower cap.

In the present embodiment, the other end side of the pressure-sensitive unit 40 is configured to connect the pressure-sensitive bellows 41 and the bellows upper cover 43, but is not limited thereto. For example, the pressure-sensitive bellows 41 having the flange-shaped upper end portion may be used, the bellows upper cover 43 may be omitted, the outer edge of the upper end portion of the pressure-sensitive bellows 41 may be fixed to the inner wall of the valve housing 10 as the valve body 5 so as not to be relatively displaceable, and the valve housing 10 may be used as the bellows upper cover 43. In this way, when the upper end portion of the pressure-sensitive bellows 41 is fixed to the inner wall of the valve housing 10, the insertion hole 43a and the sliding portion 43c of the bellows upper cover 43 are formed in the inner wall of the valve housing 10.

In the pressure regulating valve 100a of the present embodiment, the lower connecting mechanism 60 is disposed between axially facing surfaces of the needle 30 and the pressure-sensitive cell 40.

The lower connecting mechanism 60 includes a pair of recessed

portions

61 and 62 formed on axially opposite surfaces of the needle 30 and the pressure-sensitive unit 40, and a ball 63 sandwiched between the pair of recessed

portions

61 and 62 so as to form a concave-convex engagement. The pair of recessed

portions

61 and 62 are formed in the axial center portion of the upper end surface of the valve portion 32 and the lower end surface of the large diameter portion 45a, and are constituted by a lower recessed portion 61 and an upper recessed portion 62 having a conical shape. The conical shape has a bottom surface formed as a concentric circle with the central axis C and an apex located on the central axis C. The ball 63 is made of metal such as stainless steel.

Thus, the needle 30 is disposed so as to be guided along the center axis C in the needle guide hole 13 of the valve housing 10, and therefore the center position of the lower recessed portion 61 is always positioned on the center axis C. Further, since the centering action is applied to the upper recessed portion 62 via the lower recessed portion 61 and the ball 63, the center position of the upper recessed portion 62 is arranged to be self-standing on the center axis C. This can suppress transmission of the biasing force not along the center axis C to the needle 30 due to asymmetry of the pressure-sensitive bellows 41 or the like, and can reduce the sliding resistance of the needle 30. In the present embodiment, the lower recessed portion 61 and the upper recessed portion 62 each have a conical shape, but the present invention is not limited thereto, and may have a spherical shape, for example.

Adjustment spring unit

The adjustment spring unit 50 includes a spring holder member 51, an adjustment screw member 52, and an adjustment spring 53 that is sandwiched between the spring holder member 51 and the adjustment screw member 52 and biases the valve portion 32 in the valve closing direction. The spring receiver member 51 and the adjustment screw member 52 are made of a suitable material such as a metal such as brass, iron, aluminum, or stainless steel, or a resin material such as polyphenylene sulfide (PPS), and are accommodated in the spring accommodation chamber 21 of the spring case 20. By screwing the male screw portion 52c provided on the outer peripheral side of the adjustment screw member 52 to the female screw portion 22 provided on the inner peripheral side of the other end portion of the spring housing 20 and moving the adjustment screw member 52 in the axial direction, the biasing force of the adjustment spring 53 can be adjusted, and the pressure (set value) at which the needle 30 opens the valve can be adjusted.

Wave spring

The pressure regulating valve 100a of the present embodiment employs a multiple-winding type wave spring (hereinafter referred to as "wave spring") as the regulating spring 53. As shown in fig. 2, the adjustment spring 53 formed of a wave spring is formed into a cylindrical shape as a whole by bending a wire rod having a rectangular cross-sectional shape in a sine wave shape at predetermined pitches, forming a crest portion 53c and a trough portion 53v in a direction along the spring center axis, and spirally winding the wire rod between an upper end portion 53u and a lower end portion 53 d. The wave spring is made of stainless steel such as SUS304, and contact portions 53t and separation portions 53s, which contact and separate crest portions 53c and trough portions 53v facing each other in the spring center axis direction, are alternately formed in the winding direction and are arranged in a staggered manner in the spring center axis direction.

Therefore, in the pressure regulating valve 100a of the present embodiment, the plurality of contact portions 53t always serve as fulcrums when the wave spring is compressed, and since the urging force is reliably transmitted along the center axis C and the lateral force is suppressed, the conventional problem (increase in sliding resistance) can be solved, and the hysteresis can be reduced. When the wave spring is compressed, the contact portion 53t serves as a fulcrum, while the separation portion 53s is deflected in the spring center axis direction, whereby the spring constant can be increased with a small wire diameter. Therefore, the pressure regulating valve 100a of the present embodiment can be made smaller by reducing the weight and the back of the regulating spring 53 as compared with the conventional pressure regulating valve 300.

Here, since the wave spring has the contact portion 53t, the sliding resistance of the contact portion 53t increases or decreases due to adhesion of the control fluid, oil, foreign matter, and the like to the contact portion 53t, and as a result, the spring characteristics of the wave spring may change. Therefore, the wave spring of the pressure regulating valve 100a of the present embodiment is separated from the control fluid and the like, and is housed in the spring housing 20 of the valve main body 5, so that the wave spring can be used without changing the spring characteristics.

At least one round of flat wire material not formed into a sine wave shape is wound around the upper end portion 53u and the lower end portion 53d of the wave spring as the upper seat portion 53su and the lower seat portion 53 sd.

Therefore, in the present embodiment, since the upper seat portion 53su and the lower seat portion 5sd (seat portions) having an annular shape are formed at the upper end portion 53u and the lower end portion 53d (both end portions) of the wave spring, the biasing force of the wave spring can be uniformly transmitted to the adjustment screw member 52 and the spring holder member 51 in the circumferential direction via the upper seat portion 53su and the lower seat portion 53 sd.

Graph of load-deflection line for wave spring

In the wave spring, the contact portion 53t always serves as a fulcrum by compression, and the separation portion 53s is deflected, so that the contact state between the crest portion 53c and the trough portion 53v in the contact portion 53t is changed from the line contact state to the surface contact state. Thus, the load-deflection line graph of the wave spring has a non-linear characteristic.

Here, fig. 3 shows, as an example, the load-deflection characteristic of a wave spring having a nonlinear characteristic including two spring constant inflection points. In the load-deflection characteristic, a plurality of linear characteristics are combined via a spring constant inflection point (corresponding to a point where the deflection is about 50% and about 80% in fig. 3).

In the pressure regulating valve 100a of the present embodiment, the range of use of the wave spring is set so as to avoid the inflection point of the spring constant so that the wave spring has a linear characteristic from the valve closed state of the valve portion 32 to the valve fully open state where a predetermined flow rate flows, and smooth control is possible. Specifically, as shown in fig. 3, the installation length of the wave spring at the time of assembly is set so that the deflection corresponding to the valve lift amount of the needle 30 from the valve-closed state to the valve fully-opened state is included in the use range (1) and the use range (2) avoiding the inflection point of the spring constant.

In the pressure regulating valve 100a of the present embodiment, one type of wave spring is used to correspond to various control fluids, and for example, when carbon dioxide is used as the control fluid, the use pressure is high, and therefore, the use range (2) can be set to have a small flexibility, and when a refrigerant such as HFC or HFO is used as the control fluid, the use pressure is low, and therefore, the use range (1) can be set to have a large flexibility.

In addition, since the design load required for the adjustment spring 53 is increased when carbon dioxide is used as the control fluid, the influence of the lateral force may be more significantly generated when a coil spring is used as the adjustment spring 53. In contrast, in the pressure regulating valve 100a of the present embodiment, since the wave spring is used as the regulating spring 53, even if carbon dioxide is used as the control fluid, the plurality of contact portions 53t always serve as fulcrums, and the biasing force can be reliably transmitted along the central axis C, and the lateral force can be more effectively suppressed. Therefore, the pressure regulating valve 100a in the present embodiment can reduce hysteresis even in a large range of use pressure from low pressure to high pressure, and thus can improve versatility.

Here, the adjustment spring 53 of the pressure adjustment valve 100a in the present embodiment is a wave spring instead of the coil spring of the conventional pressure adjustment valve 300. Here, the number of turns of the wave spring becomes extremely large as compared with the coil spring. Therefore, the problems of the conventional pressure regulating valve 300 caused by the expansion and rotation of the coil spring during compression may be more significantly caused by the wave spring of the pressure regulating valve 100a of the present embodiment. Therefore, in the pressure regulating valve 100a of the present embodiment, problems caused by expansion and rotation during compression are suppressed by studying the supporting mechanism of the wave spring.

First, a supporting mechanism of the coil spring in the conventional pressure regulating valve 300 will be described, and problems caused by the expansion and rotation of the coil spring during compression will be described.

Support mechanism for coil spring in conventional pressure adjustment valve

As shown in fig. 6, in the conventional support mechanism for the coil spring of the pressure regulating valve 300, the outer diameters of the boss portion of the spring support member 351 and the boss portion of the adjustment screw member 352 are made smaller than the inner diameter of the adjustment spring 353 composed of a coil spring, and the boss portions of the spring support member 351 and the adjustment screw member 352 are inserted into the lower end side and the upper end side of the adjustment spring 353 to be supported. Here, the lower end side of the adjustment spring 353 is supported by the rotatable connecting rod 345 via the spring holder member 351, but the connecting rod 345 is inclined by the lateral force generated by the adjustment spring 353. Thereby, the sliding resistance between the connecting rod 345 and the insertion hole 343a increases, and the spring holder member 351 connected to the connecting rod 345 is in a state of being difficult to rotate.

Here, although the adjustment spring 353 is slightly compressed, the coil diameter is enlarged as the deflection increases, and the gap with respect to the boss portions on the lower end side and the upper end side increases, so that there is a concern that: since the adjustment spring 353 is easily displaced in the radial direction, it is easily tilted, and the lower end portion and the upper end portion are rotated about the center axis C, so that the adjustment spring 353 slides with respect to the spring holder member 351 and the adjustment screw member 352. When the adjustment spring 353 is viewed from the spring center axis direction, stepped portions (not shown) as a winding start portion or a winding end portion are formed between the lower end portion and the upper end portion of the adjustment spring 353 and the wire material overlapping the lower end portion and the upper end portion. Therefore, in the conventional pressure regulating valve 300, the lower end portion and the upper end portion of the regulating spring 353 are compressed with respect to the spring support member 351 and the regulating screw member 352 and rotate while rubbing against the stepped portions, and therefore, a smooth rotating operation cannot be performed, and there is a possibility that a problem (hereinafter, referred to as "a problem point of the spring (vibration due to rotation)") occurs in which the regulating spring 353 vibrates.

Here, as the pressure adjusting valve 100a in the present embodiment, a support mechanism of a coil spring in the conventional pressure adjusting valve 300 is directly used, and only a wave spring is used instead of the coil spring. In this case, since the number of turns of the wave spring is extremely large as compared with the coil spring, the range of rotation of the lower end portion 53d and the upper end portion 53u of the wave spring during compression becomes large, and a problem of the spring (vibration due to rotation) occurs more significantly, and it may be difficult to perform flow rate adjustment with higher accuracy.

Supporting mechanism for wave spring

Therefore, the pressure regulating valve 100a of the present embodiment employs a supporting mechanism for a wave spring, which is completely different from the conventional pressure regulating valve 300. As shown in fig. 1, the supporting mechanism of the wave spring is composed of a spring holder member 51, an adjusting screw member 52, and an upper connecting mechanism 70 disposed between the connecting rod 45 and the spring holder member 51.

The spring receiver member 51 includes a boss portion (convex portion) 51a extending toward the other end side in the direction of the center axis C, and a flange portion (convex portion) 51b provided at one end side and used for seating a lower seat portion 53sd (see fig. 2) of the wave spring. The adjustment screw member 52 includes an annular wall portion (concave portion) 52a extending toward one end side in the direction of the center axis C, and an upper surface portion (concave portion) 52b provided on the other end side and on which an upper seat portion 53su (see fig. 2) for the wave spring is seated. Here, in the supporting mechanism of the wave spring of the present embodiment, the outer diameter of the boss portion 51a of the spring bearing member 51 is made slightly smaller than the inner diameter of the wave spring, and the boss portion 51a is inserted into the lower end side of the wave spring, so that there is a gap in which the wave spring can slide in the radial direction, and the wave spring is supported by the boss portion 51b in the axial direction. The inner diameter of the annular wall portion 52a of the adjustment screw member 52 is slightly larger than the outer diameter of the wave spring, and the upper end side of the wave spring is inserted into the annular wall portion 52a, whereby the wave spring is supported by the upper surface portion 52b in the axial direction with a gap in the radial direction.

The upper connecting mechanism 70 includes: a pair of engaging

portions

71, 72 formed on axially opposite surfaces of the connecting rod 45 and the spring holder member 51; and a connecting member 73b having a spherical shape and sandwiched between the pair of engaging

portions

71, 72 so as to form a concave-convex engagement. The pair of engaging

portions

71, 72 are formed on the upper end surface of the small diameter portion 45b and the axial center portion of the lower end surface of the spring holder member 51, and are constituted by a lower engaging portion 71 and an upper engaging portion 72 having a conical shape. The conical shape has a bottom surface formed concentrically with the central axis C and an apex located on the central axis C. The connecting member 73b is made of metal such as stainless steel.

Here, since the radius of the circular side portion of the connecting member 73b is set to be slightly smaller than the radius of the sliding portion 43C when viewed from the direction of the center axis C, an extremely narrow gap is formed between the side portion of the connecting member 73b and the sliding portion 43C. Therefore, since the side portion of the link member 73b and the sliding portion 43C are always in a point contact state and the movement in the radial direction is restricted, the center position of the link member 73b is always arranged in the vicinity of the center axis C. Further, since the connection member 73b, whose movement in the radial direction is restricted, acts centripetally on the lower engagement portion 71 and the upper engagement portion 72, respectively, the center positions of the lower engagement portion 71 and the upper engagement portion 72 are arranged in the vicinity of the central axis C so as to be self-supporting. The small diameter portion 45b of the connecting rod 45 is set to be inserted through the insertion hole 43a along the center axis C in a non-contact state. Thus, the upper link mechanism 70 can reduce the sliding resistance with the sliding portion 43C while suppressing the inclination of the connecting rod 45 with respect to the center axis C, and can reduce the hysteresis.

About the action of the supporting mechanism of the wave spring during compression

As shown in fig. 2, the upper end side and the lower end side of the wave spring have stepped portions 53st formed on an upper seat portion 53su and a lower seat portion 53sd facing the upper end portion 53u and the lower end portion 53d, as in the case of the coil spring.

First, as shown in fig. 1, on the upper end side of the wave spring, the upper seat portion 53su of the wave spring is seated on the upper surface portion 52b of the adjustment screw member 52, and the outer peripheral surface of the wave spring is supported with a gap from the inner peripheral surface of the annular wall portion 52a of the adjustment screw member 52. Therefore, when the wave spring expands in diameter during compression, the gap between the wave spring and the adjustment screw member 52 becomes narrow, and the wave spring is less likely to be displaced in the radial direction. Thus, the stepped portion 53st on the upper end side of the wave spring rotates while rubbing against the upper surface portion 52b of the adjustment screw member 52, and even if the wave spring vibrates, the outer peripheral surface of the wave spring can be in contact with the inner peripheral surface of the annular wall portion 52a of the adjustment screw member 52, and thus the vibration generated by the wave spring can be effectively damped.

Next, on the lower end side of the wave spring, the lower seat portion 53sd of the wave spring is seated on the flange portion 51b of the spring holder member 51, and the inner peripheral surface of the wave spring is supported with a gap from the outer peripheral surface of the boss portion 51a of the spring holder member 51. Here, the static friction force generated between the lower seat portion 53sd of the wave spring and the flange portion 51b of the spring bearing member 51 (surface contact) is set to be larger than the static friction force generated between the spring bearing member 51 and the connecting member (connecting mechanism) 73b (annular line contact). Further, a rotatable concave-convex engagement is formed between the pressure-sensitive unit 40 and the adjustment spring unit 50. Therefore, when the wave spring is compressed, the lower seat portion 53sd of the wave spring does not rub against the flange portion 51b of the spring holder member 51 due to a large static friction force, but rotates integrally. Thereby, the spring bearing member 51 can relatively rotate with respect to the pressure-sensitive unit 40 via the upper link mechanism 70.

Therefore, since the pressure regulating valve 100a of the present embodiment includes the support mechanism for the wave spring, the outer peripheral surface on the upper end side of the wave spring can be brought into contact with the inner peripheral surface of the annular wall portion 52a of the adjustment screw member 52 during compression, and vibration generated by the wave spring can be effectively damped. Further, since the lower end side of the wave spring does not move relative to the spring bearing member 51 during compression, the stepped portion 53st can suppress the wave spring from vibrating. Thus, the pressure regulating valve 100a of the present embodiment can eliminate the spring problem (vibration due to rotation) of the conventional pressure regulating valve 300, and can adjust the flow rate with higher accuracy.

Operation of pressure regulating valve

The operation of the pressure regulating valve 100a will be described. Here, the refrigerant circuit will be described with respect to the use of the pressure regulating valve 100a, but the present invention is not limited thereto. In the pressure regulating valve 100a, the inlet port 11 is connected to the inlet pipe 1 on the high pressure (primary pressure P1) side, and the outlet port 12 is connected to the outlet pipe 2 on the low pressure (secondary pressure P2) side.

(case where the primary pressure P1 is lower than the set value)

When the primary-side pressure P1 is lower than the set value (for example, when the discharge pressure of the compressor is lowered), the valve portion 32 is seated on the valve seat 18 and is closed as shown in fig. 1. At this time, the secondary pressure P2 is introduced into the space outside the pressure-sensitive bellows 41 as the bellows housing chamber 16 via the valve chamber 15.

First, as a pressure acting in a direction in which the valve portion 32 opens, a secondary pressure P2 × an effective pressure receiving area S1 is generated in the pressure-sensitive bellows 41 (see fig. 1 (b)). Here, the effective pressure receiving area S1 of the pressure-sensitive bellows 41 is a pressure receiving area calculated based on the average inner diameter of the minimum inner diameter and the maximum inner diameter of the bellows shape.

Next, as the pressure acting in the valve portion 32 opening direction, the primary pressure P1 × the pressure receiving area S2 is generated in the needle 30 (see fig. 1 (b)), and on the other hand, as the pressure acting in the valve portion 32 closing direction, the secondary pressure P2 × the pressure receiving area S2 is generated in the needle 30 (see fig. 1 (b)). Further, as a force acting in the closing direction of the valve portion 32, a biasing force F1 by the pressure-sensitive bellows 41 and a biasing force F2 by the adjustment spring 53 are applied to the needle 30. In addition, the valve spring 6 applies an urging force to the needle 30 as a force acting in a direction in which the valve portion 32 opens. The biasing force of the valve spring 6 is a biasing force of a degree to cancel out the own weight of the needle 30, and therefore (expression 1) below is not introduced.

Therefore, the balance of the external forces acting on the valve needle 30 of the pressure regulating valve 100a can be expressed as follows.

P2 × S1+ P1 × S2 ═ P2 × S2+ F1+ F2 (formula 1)

Here, P1: primary side pressure [ N/mm ] ² ]

P2: secondary side pressure [ N/mm ] ² ]

S1: effective pressure receiving area [ mm ] of pressure-sensitive bellows 41 ² ]

S2: the pressure-receiving area [ mm ] of the valve portion 32 surrounded by the valve seat 18 ² ]

F1: acting force of pressure-sensitive bellows 41 [ N ]

F2: adjusting the force of spring 53 [ N ]

(formula 1) can be arranged as P2 × S1+ P1 × S2-P2 × S2 ═ F1+ F2. Here, the effective pressure receiving area S1 of the pressure-sensitive bellows 41 is set to coincide with the pressure receiving area S2 of the valve portion 32 surrounded by the valve seat 18.

Therefore, in the (expression 1), the external force acting on the needle 30 from the secondary pressure P2 is completely cancelled, and the above expression can be further summarized as P1 × S2 — F1+ F2. In the pressure regulating valve 100a of the present embodiment, since the effective pressure receiving area S1 of the pressure-sensitive bellows 41 can be easily adjusted, the effective pressure receiving area S1 is set to coincide with the pressure receiving area S2 of the valve portion 32 surrounded by the valve seat 18, and the influence of the secondary pressure P2 can be canceled out. Thus, the pressure regulating valve 100a can variably control the opening degree in accordance with the variation in the primary pressure by moving the adjustment screw member 52 in the axial direction and appropriately setting the biasing force F2 of the adjustment spring 53. The dimensions of each part of the pressure regulating valve 100a can be set using an actual pressure receiving area obtained through an experiment, without being limited to the pressure receiving area (effective pressure receiving area) which is an approximate value calculated based on the average inner diameter of the minimum inner diameter and the maximum inner diameter of the bellows shape.

(case where the primary pressure P1 is higher than the set value)

When the primary side pressure P1 is higher than the set value ((F1+ F2)/S2) (for example, when the discharge pressure of the compressor is increased), the valve portion 32 is separated from the valve seat 18 and is in an open valve state, although not shown. At this time, the valve opening degree increases as the primary side pressure P1 increases. Here, the pressure regulating valve 100a of the present embodiment uses the pressure-sensitive bellows 41 as the pressure-sensitive member, and thus can obtain a large valve lift amount.

The pressure regulating valve 100a of the present embodiment employs a wave spring as the regulating spring 53, and thus can suppress a lateral force, eliminate a conventional problem (increase in sliding resistance), and reduce hysteresis. Further, in the pressure regulating valve 100a of the present embodiment, as the supporting mechanism of the wave spring, one end side and the other end side of the wave spring are supported by the

convex seating portions

51a and 51b and the

concave seating portions

52a and 52b, respectively, and the concave-convex engagement which has a centripetal action and is rotatable is formed between the pressure-sensitive unit 40 and the regulating spring unit 50, so that the problem points (vibration due to rotation) of the spring can be eliminated, and the flow rate can be regulated with higher accuracy.

(modification of the first embodiment)

A pressure regulating valve 100b according to a modification of the first embodiment of the present invention will be described with reference to fig. 4. The pressure adjusting valve 100b according to the modification of the first embodiment differs from the pressure adjusting valve 100a according to the first embodiment in that the spherical connecting member 73b of the upper connecting mechanism 70 is integrally formed with the other end side of the connecting rod 45, and the inner diameters of the sliding portion 43c and the insertion hole 43a are set to be the same. Here, the same components are denoted by the same reference numerals, and redundant description thereof is omitted.

The upper connection mechanism (connection mechanism) 170 of the modification of the first embodiment is constituted by the upper engagement portion 72 of the spring bearing member 51 and a connection member 173b integrally formed at the other end portion of the connection rod 145. The conical upper engaging portion 72 and the spherical connecting member 173b face each other in the direction of the central axis C, and form a concave-convex engagement. The bellows upper cover (cover on the side of the adjustment spring unit) 143 of the modification of the first embodiment includes a cylindrical sliding portion 143C extending concentrically along the center axis C and allowing the connection member 173b to slide.

Here, since the radius of the circular side portion of the connection member 173b is set slightly smaller than the radius of the sliding portion 143C when viewed from the direction of the central axis C, an extremely narrow gap is formed between the side portion of the connection member 173b and the sliding portion 143C. Thus, the side portion of the connecting member 173b and the sliding portion 143C are always in a line contact state, but since the side force is suppressed by using the wave spring, the center position of the small diameter portion 145b of the connecting rod 145 is always disposed in the vicinity of the central axis C. Therefore, the upper connection mechanism 170 can reduce the sliding resistance with the sliding portion 43C and reduce the hysteresis while suppressing the inclination of the connection rod 145 with respect to the central axis C.

As described above, in the pressure regulating valve 100b according to the modification of the first embodiment, the connecting member 73b according to the first embodiment is integrated with the other end side of the connecting rod 45, and the inner diameters of the sliding portion 43c and the insertion hole 43a are set to be the same, whereby the same effects as those of the first embodiment (reduction of hysteresis, vibration due to rotation, and the like) can be obtained, and the burden on the assembly work and the management of the members can be reduced.

(second embodiment)

A pressure regulating valve 200 according to a second embodiment of the present invention will be described with reference to fig. 5. The pressure regulating valve 200 of the second embodiment is different from the pressure regulating valve 100a of the first embodiment mainly in that a pressure-sensitive diaphragm 241 is used as a pressure-sensitive member instead of the pressure-sensitive bellows 41 and the flow direction of the control fluid is reversed, but the other basic configuration is substantially the same as that of the first embodiment. Here, the same components are denoted by the same reference numerals, and redundant description thereof is omitted.

The pressure regulating valve 200 of the second embodiment is mainly different from the pressure regulating valve 100a of the first embodiment in the pressure-sensitive unit 240, the valve main body 205, and the upper connection mechanism (connection mechanism) 270, which are explained in this order.

First, the pressure-sensitive unit 240 is made of metal such as stainless steel, and is made up of a pressure-sensitive diaphragm (pressure-sensitive member) 241, a diaphragm lower cover 242, a diaphragm upper cover (cover on the adjustment spring unit side) 243, a pressure plate 244 provided on the upper surface of the pressure-sensitive diaphragm 241, and a connecting rod 245 having one end and the other end extending along the central axis C. Here, in a state where the pressure-sensitive membrane 241 is sandwiched between the membrane lower cover 242 and the membrane upper cover 243, the membrane lower cover 242, the pressure-sensitive membrane 241, and the membrane upper cover 243 are integrally fixed via the welding portion w.

The other end of the valve housing 210 is fixed to an opening of the diaphragm lower cover 242 to define a pressure-sensitive chamber 242a by the lower surface of the pressure-sensitive diaphragm 241, while the one end of the spring housing 20 is fixed to the diaphragm upper cover 243 to introduce the atmosphere at all times. The diaphragm upper cover 243 includes a cylindrical sliding portion 243C extending concentrically along the center axis C, and a stopper portion 243 s. The stopper 243s abuts against the pressure plate 244 to define the maximum valve lift amount L2 from the valve closed state to the valve fully opened state in which the valve needle 30 is in the maximum valve lift state.

The connecting rod 245 is constantly biased in the valve opening direction by the auxiliary spring 208 interposed between the valve case 210 and the retainer 207 fixed near the other end of the connecting rod 245, and the other end of the connecting rod 245 having a planar shape abuts on the lower surface of the pressure-sensitive membrane 241. The biasing force of the assist spring 208 is set to such a degree that the connecting rod 245 can always follow the pressure-sensitive diaphragm 241 in a contact state.

Next, the valve main body 205 is composed of a valve housing 210 connected to the inflow pipe 201 and the outflow pipe 202, and a spring housing 20 coupled to the other end portion of the valve housing 210 via a pressure-sensitive unit 240.

The valve housing 210 is a hollow cylindrical member, and is provided with an inlet port 211 penetrating from the valve chamber 15 in the radial direction and connected to the inlet pipe 201, an outlet port 212 penetrating along the central axis C and connected to the outlet pipe 202, and a pressure equalizing hole 213 formed at a position offset from the central axis C in the radial direction. The primary-side pressure P1 is introduced into the pressure-sensitive chamber 242a of the pressure-sensitive cell 240 through the inlet port 211 in the closed state by the pressure equalizing hole 213.

Further, the upper connection mechanism 270 is constituted by: a pair of engaging

portions

271 and 72 formed on axially opposite surfaces of the platen 244 and the spring holder member 51; and a connecting member 73b having a spherical shape and sandwiched between the pair of engaging

portions

271 and 72 so as to form a concave-convex engagement. The pair of engaging

portions

271, 72 are formed in the axial center portion of the upper end surface of the platen 244 and the lower end surface of the spring holder member 51, and are constituted by a lower engaging portion 271 and an upper engaging portion 72 having a conical shape. The conical shape has a bottom surface formed concentrically with the central axis C and an apex located on the central axis C.

Here, since the radius of the circular side portion of the connecting member 73b is set to be slightly smaller than the radius of the sliding portion 243C when viewed from the direction of the center axis C, an extremely narrow gap is formed between the side portion of the connecting member 73b and the sliding portion 243C. Thus, the side portion of the link member 73b and the sliding portion 243C are always in a point contact state, and the movement in the radial direction is restricted, so that the center position of the link member 73b is always arranged in the vicinity of the center axis C. Further, since the centering action acts on the lower engagement portion 271 and the upper engagement portion 72 via the connection member 73b whose movement in the radial direction is restricted, the center positions of the lower engagement portion 271 and the upper engagement portion 72 are arranged in the vicinity of the center axis C so as to be self-supporting. This reduces the sliding resistance with the sliding portion 243c and reduces the hysteresis in the upper connection mechanism 270. The movable range of the pressure-sensitive membrane 241 in the vertical direction (the maximum valve lift amount L2) is, for example, about 0.2mm, and therefore, the movable range can be guided by the sliding portion 243c formed by the thickness of the membrane upper cover 243.

As described above, in the pressure regulating valve 200 of the second embodiment, the pressure-sensitive diaphragm 241 is used as the pressure-sensitive member instead of the pressure-sensitive bellows 41, and the flow direction of the control fluid is reversed, whereby the versatility can be improved by matching the flow direction of the pressure-sensitive member, the control fluid, and the like to the use application, in addition to obtaining the same effects (reduction of hysteresis, vibration due to rotation, and the like) as those of the first embodiment.

Other modes

The

pressure regulating valves

100a, 100b, and 200 according to the present embodiment can be applied not only to the refrigerant circuits of the examples, but also to all fluid devices and fluid circuits. The present invention is not limited to the above-described embodiments and modifications described therein, and can be modified and modified as appropriate without departing from the scope of the technical spirit of the present invention.

Claims

1. A pressure regulating valve is characterized by comprising:

a valve body having a valve seat;

a valve needle having a valve portion that can be brought into contact with and separated from the valve seat;

a pressure-sensitive unit having a pressure-sensitive member that is deflected in an axial direction and that biases the valve portion;

an adjustment spring unit having an adjustment spring for urging the valve portion in a valve closing direction via the pressure-sensitive member; and

a connection mechanism which forms a concave-convex clamping with centripetal action between the pressure-sensitive unit and the adjusting spring unit,

the adjusting spring is a wave spring.

2. The pressure regulating valve according to claim 1,

the adjusting spring unit is also provided with a spring support component with a convex part and an adjusting screw component with a concave part,

the needle side and the adjustment spring unit side of the wave spring are supported by the convex portion and the concave portion, respectively,

the spring holder member is rotatable relative to the pressure-sensitive unit via the connection mechanism.

3. The pressure regulating valve according to claim 1,

the static friction force generated between the needle side of the wave spring and the spring receiver member is set to be larger than the static friction force generated between the spring receiver member and the coupling mechanism.

4. The pressure regulating valve according to any one of claims 1 to 3,

flat ring-shaped seat portions are provided at both end portions of the wave spring, respectively.

5. The pressure regulating valve according to any one of claims 1 to 4,

the range of use of the wave spring is set so as to avoid an inflection point of a spring constant so that the wave spring has a linear characteristic from a closed state to a fully opened state of the valve portion.

6. The pressure regulating valve according to any one of claims 1 to 5,

the wave spring is housed in a spring case of the valve main body that is separated from the control fluid.

7. The pressure regulating valve according to any one of claims 1 to 6,

carbon dioxide is used as the control fluid.

8. The pressure regulating valve according to any one of claims 1 to 7,

the pressure-sensitive unit further includes a cover on the adjustment spring unit side having a cylindrical sliding portion communicating in the axial direction,

the connecting mechanism includes a connecting member having a circular side portion when viewed from the axial direction,

the side portion of the connecting member is point-contacted with the sliding portion.

9. The pressure regulating valve according to claim 8,

the pressure-sensitive unit further includes: a connecting rod, an end of the connecting rod on the side of the adjusting spring unit being configured to be inserted into the sliding part; and the pressure-sensitive member constituted by a pressure-sensitive bellows, an end portion of the pressure-sensitive bellows on the needle side being connected to the connection rod, and an end portion of the pressure-sensitive bellows on the adjustment spring unit side being fixed so as not to be relatively displaceable with respect to the valve main body,

the connecting mechanism further includes an engaging portion provided in an axial center portion of the needle-side end portion of the adjusting spring unit,

the engaging portion and the connecting member have a shape recessed toward the adjustment spring unit side and a shape protruding therefrom, and form a concave-convex engagement.