Pilot type pressure control valve

Abstract

To provide a pilot type pressure control valve capable of suppressing abrupt pressure fluctuation to a pressure sensing part to improve reliability, without requiring a complicated process.SOLUTION: A pilot type pressure control valve comprises: a main valve part 100a having pressure fluctuation damping means; a pilot part 200a having a pressure sensing part 251; and a fluid flow path connecting a pressure equalizing port 113 and a main valve port 112 in the main valve part 100a to a pilot inflow port 211 and a pilot valve port 231a in the pilot part 200a, respectively. The pressure fluctuation damping means forms a circumferentially extending gap Gc between the main valve element 140 in the main valve part 100a and a main valve guide hole 105b, and constantly communicates a main valve chamber 125 and a back pressure chamber 105c to a pressure sensing part housing chamber 216 only through the circumferentially extending gap Gc. Consequently, it is possible to eliminate the conventional problem (decrease in durability of the pressure sensing part due to fluctuation in primary pressure).SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a pilot-operated pressure regulating valve having a pressure-sensing portion. [Background technology]

[0002] Some pressure regulating valves have a pressure-sensing unit, and depending on the drive method, they can be broadly classified into direct-acting types, in which the main valve body is directly driven by the displacement of the pressure-sensing unit connected to the main valve body, and pilot types, in which the pressure in the back pressure chamber is adjusted by the displacement of the pressure-sensing unit connected to the pilot valve body, and the main valve body is driven by the differential pressure between this back pressure chamber and the primary side pressure.

[0003] Because pressure regulating valves with pressure-sensing units do not require complicated control circuits, they are less expensive and more reliable than pressure regulating valves with solenoids, etc., and there is a demand for expanded use in fluid circuits with large flow rates. In fluid circuits with large flow rates, the diameter of the main valve port of the main valve unit is inevitably larger, which requires a larger driving force for the main valve unit. For this reason, while direct-acting types have limitations on the driving force of the pressure-sensing unit, pilot-operated types allow for relatively easy adjustment of the driving force for the main valve unit, i.e., the magnitude of the pressure difference between the back pressure chamber and the primary pressure, and are therefore widely used in fluid circuits with large flow rates.

[0004] 11, Patent Document 1 describes a pilot-operated pressure regulating valve 1100 (hereinafter referred to as a "conventional pilot-operated pressure regulating valve") having a reversing plate 1251, which includes, in order along an axis L, a main valve port 1112, a main valve seat 1105a, a main valve chamber 1125, a back pressure chamber 1105c, and a pressure-sensing portion accommodating chamber 1216, and further includes a main valve inlet port 1111 communicating with the main valve chamber 1125, and a small flow passage 1138 communicating between the main valve chamber 1125 and the back pressure chamber 1105c. Patent Document 1 also describes a main valve element 1140 that can be brought into contact with or separated from the main valve seat 1105a depending on the pressure difference between the main valve chamber 1125 and the back pressure chamber 1105c. In Patent Document 1, a primary pressure P1 and a secondary pressure P2 are introduced into a main valve inlet port 1111 and a main valve port 1112 via a first joint pipe 1101 and a second joint pipe 1102, respectively.

[0005] Furthermore, Patent Document 1 describes a valve having a reversible plate 1251 accommodated in the pressure sensing portion accommodating chamber 1216, a pilot communication passage 1226 communicating with the back pressure chamber 1105c via a pilot valve seat 1231c, and an internal communication passage 1237 communicating between the main valve inlet port 1111 and the pressure sensing portion accommodating chamber 1216. In addition, Patent Document 1 describes a valve having a pilot valve element 1240 that is connected to the reversible plate 1251 and can come into contact with or separate from the pilot valve seat 1231c in response to a snap-action reversal movement of the reversible plate 1251.

[0006] As a result, in the conventional pilot-operated pressure regulating valve 1100, the fluid pressure in the main valve chamber 1125 and the main valve port 1112 acts on the main valve element 1140 in the valve opening direction, and the fluid pressure in the back pressure chamber 1105c acts on the main valve element 1140 in the valve closing direction, so that the opening and closing of the main valve port 1112 is controlled by this main valve element 1140 (see white arrow M1102 in FIG. 11). Also, the fluid pressure in this back pressure chamber 1105c responds to the displacement of the reversing plate 1251, which is sensitive to the fluid pressure in the main valve inlet port 1111, and the pilot valve element 1240 controls the opening and closing of the pilot communicating passage 1226 (see white arrow M1101 in FIG. 11).

[0007] Here, in the conventional pilot-operated pressure regulating valve 1100, the pressure-sensing unit accommodating chamber 1216 in which the reversing plate 1251 is accommodated is constantly in communication with the main valve inlet port 1111 via the internal communication passage 1237, and the reversing plate 1251 is repeatedly subjected to unsteady pressure fluctuations in the primary side pressure P1, specifically, impact pressure due to sudden increases in pressure, etc., which could result in a decrease in the durability of the reversing plate 1251 (hereinafter referred to as the "conventional problem (decrease in durability of the pressure-sensing unit due to primary side pressure fluctuations)").

[0008] In order to solve the conventional problem (reduced durability of the pressure-sensing part due to pressure fluctuations in the primary pressure), it is conceivable to suppress pressure fluctuations on the reversal plate 1251 by reducing the diameter of the internal connecting passage 1237, but this cannot be adopted because it is difficult to process fine holes and new issues arise, such as high costs. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-349732 Summary of the Invention [Problem to be solved by the invention]

[0010] An object of the present invention is to provide a pilot-operated pressure regulating valve that can suppress sudden pressure fluctuations in a pressure-sensing portion and improve reliability without requiring complex processing. [Means for solving the problem]

[0011] In order to solve the above problems, the pilot operated pressure regulating valve is a main valve portion including a main valve chamber, an inlet port communicating with the main valve chamber, a main valve port communicating with the main valve chamber via a main valve seat, a main valve element that can abut against or move away from the main valve seat, a main valve guide hole that guides the main valve element in the axial direction, and a back pressure chamber that is provided on the opposite side of the main valve chamber from the main valve chamber, and which constantly communicates the main valve chamber with the back pressure chamber and moderates pressure fluctuations from the main valve chamber to the back pressure chamber. a main valve portion having a pressure fluctuation buffering means for impacting the back pressure chamber with the pressure fluctuation buffering means and a pressure equalizing port communicating with the back pressure chamber; and a pilot valve portion having a pressure sensing portion, a pressure sensing portion accommodating chamber for accommodating the pressure sensing portion, a pilot inlet port communicating with the pressure sensing portion accommodating chamber, a pilot valve port communicating with the pressure sensing portion accommodating chamber via a pilot valve seat, and a pilot valve body connected to the pressure sensing portion and capable of abutting against or separating from the pilot valve seat depending on the displacement of the pressure sensing portion. and fluid paths respectively communicating between the pressure equalizing port and the pilot inlet port, and between the main valve port and the pilot valve port, wherein the pressure fluctuation damping means forms a circumferentially extending gap between the main valve element and the main valve guide hole, and constantly communicates the main valve chamber and the back pressure chamber with the pressure sensing element accommodating chamber only via the circumferentially extending gap, and the pressure sensing element responds to the pressure of the inlet port via the back pressure chamber, so that when the pressure of the inlet port is lower than the valve opening pressure of the pilot element, the pressure in the back pressure chamber and the pressure in the main valve chamber are equal, and when the pressure is higher than the valve opening pressure of the pilot element and lower than the valve opening pressure of the main valve element, a pressure difference is generated between the back pressure chamber and the main valve chamber, and when the pressure of the inlet port is higher than the valve opening pressure of the main valve element, the pressure difference between the back pressure chamber and the main valve chamber causes the main valve element to open.

[0012] In the above pilot-operated pressure regulating valve, the pressure fluctuation damping means may be an uneven portion provided on the main valve body and / or the main valve guide hole.

[0013] In the above pilot-operated pressure regulating valve, the pressure fluctuation damping means may be a plurality of circumferential grooves provided in the main valve body and / or the main valve guide hole along the axial direction.

[0014] Moreover, in the above-mentioned pilot-operated pressure regulating valve, the pressure fluctuation buffering means may be a biasing means that is provided between the main valve body and a slide guide surface that is formed concentrically with the axis at a position separated from the circumferentially extending gap, and that biases the axis of the main valve body so as to follow the axial direction.

[0015] In the above pilot-operated pressure regulating valve, the pressure fluctuation damping means may be a bent portion formed in a flow path extending from the back pressure chamber to the pressure sensing portion accommodating chamber. [Effects of the Invention]

[0016] According to the present invention, it is possible to provide a pilot-operated pressure regulating valve that can suppress sudden pressure fluctuations in a pressure-sensing portion and improve reliability without requiring complex processing. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a cross-sectional view showing a pilot-operated pressure regulating valve according to a first embodiment of the present invention. [Figure 2] 2 is an explanatory diagram of an external force acting on a main valve portion surrounded by a dashed line II shown in FIG. 1. FIG. [Figure 3] 3 is an explanatory diagram of an external force acting on a pilot portion surrounded by a dashed line III shown in FIG. 1. FIG. [Figure 4] 2 is a partially enlarged view of the pilot-operated pressure regulating valve of FIG. 1, in which (a), (c), and (e) are the areas surrounded by dashed lines IVa, c, and e shown in FIG. 1, and (b), (d), and (f) are the areas surrounded by dashed lines IVb, d, and f shown in FIG. 1, in which (a) and (b) represent State 1 (the main valve unit and the pilot unit are in a valve-closed state), (c) and (d) represent State 2 (the main valve unit is in a valve-closed state, and the pilot unit is in a valve-open state), and (e) and (f) represent State 3 (the main valve unit and the pilot unit are in a valve-open state). [Figure 5] 2A and 2B are diagrams showing the fluid characteristics with respect to changes in primary pressure in the pilot-operated pressure regulating valve of FIG. 1, where (a) shows the primary pressure-intermediate pressure characteristics and (b) shows the primary pressure-flow rate characteristics. [Figure 6] FIG. 4 is a cross-sectional view showing a pilot-operated pressure regulating valve according to a second embodiment. [Figure 7] FIG. 10 is a cross-sectional view showing a pilot-operated pressure regulating valve according to a third embodiment. [Figure 8] 8A and 8B are cross-sectional views showing a pilot-operated pressure regulating valve according to a fourth embodiment, where (a) is a front cross-sectional view, and (b) is a cross-sectional view taken along line VIIIb-VIIIb shown in (a). [Figure 9] FIG. 10 is a cross-sectional view showing a pilot-operated pressure regulating valve according to a fifth embodiment. [Figure 10] 10 is a partially enlarged view of the pilot-operated pressure regulating valve of FIG. 9, where (a), (c), and (e) are the areas surrounded by dashed lines Xa, c, and e shown in FIG. 9, and (b), (d), and (f) are the areas surrounded by dashed lines Xb, d, and f shown in FIG. 9, where (a) and (b) represent state 1 (the main valve unit and the pilot unit are in a valve-closed state), (c) and (d) represent state 2 (the main valve unit is in a valve-closed state, and the pilot unit is in a valve-open state), and (e) and (f) represent state 3 (the main valve unit and the pilot unit are in a valve-open state). [Figure 11] 1 is a cross-sectional view of a pilot-operated pressure regulating valve according to the prior art. DETAILED DESCRIPTION OF THE INVENTION

[0018] An embodiment of the present invention will be described in detail with reference to Figures 1 to 10. However, the present invention is not limited to this embodiment.

[0019] <Terminology> In this specification, the terms "upper," "lower," "left," and "right" refer to the directions shown in Figures 1 to 4, 6 to 7, 8(a), and 9 to 10. In this specification and the claims, the terms "one end" and "other end" refer to the "lower end" and "upper end" in the axial direction extending vertically in the drawings. In this specification and the claims, the term "effective pressure-receiving area of ​​the pressure-sensitive bellows" refers to the pressure-receiving area as an approximate value calculated based on the average inner diameter of the bellows' minimum inner diameter (the inner diameter of the "valley" portion of the bellows' shape that protrudes toward the central axis of the pressure-sensitive bellows) and the maximum inner diameter (the inner diameter of the "peak" portion of the bellows' shape that protrudes away from the central axis of the pressure-sensitive bellows). In this specification and the claims, the term "guidable" includes "slidable." In this specification and the claims, the term "convex-concave engagement" refers to engagement between a recessed shape and a protruding shape in the axial direction, respectively. In this specification, the term "intermediate chamber" refers to a space other than the pressure-sensing portion accommodating chamber and the pilot valve chamber. In this specification, the term "circumferentially extending gap" refers to a gap that is provided between radially opposing surfaces and extends in the circumferential direction. In this specification, the term "uneven portion" refers to not only an uneven portion provided on a surface that defines the circumferentially extending gap, but also a C-shaped groove, a spiral groove, an axially extending groove, a groove inclined with respect to the axial direction, multiple recesses, multiple protrusions, an annular groove formed on one of the surfaces that defines the circumferentially extending gap and a C-shaped ring accommodated in the annular groove protruding toward the other surface, or an annular groove formed on one of the surfaces that defines the circumferentially extending gap and an O-ring accommodated in the annular groove protruding toward the other surface, and an axially extending or inclined groove on the other surface. In the description of this specification, the term "bent portion" refers to "at least one portion in which the flow path is bent by at least 90 degrees or more at any position in the intermediate pressure flow path extending from the back pressure chamber to the bellows accommodating chamber."In the description of this specification, "a fluid path that connects the main valve port and the pilot valve port" refers to "a relatively short and direct fluid path that connects the main valve port and the pilot valve port (i.e., when the main valve port and the pilot valve port have the same secondary pressure), and a relatively long and indirect fluid path that connects the main valve port and the pilot valve port (when the main valve port and the pilot valve port have different secondary pressures)."

[0020] (First embodiment) <Configuration of the pilot operated pressure regulating valve> A pilot type pressure regulating valve 300a according to a first embodiment of the present invention will be described with reference to Figures 1 to 3. The pilot type pressure regulating valve 300a is composed of a main valve portion 100a and a pilot portion 200a.

[0021] <Main valve configuration> 1 and 2, the main valve section 100a is mainly composed of a main valve body 105, a main valve element 140, and a main valve spring unit 160. Each component of the main valve section 100a will be described below in order. As will be described in detail later, in this embodiment, the pressure fluctuation damping means (1) (circumferentially extending gap) and the pressure fluctuation damping means (2) (circumferentially extending gap at the most upstream of the intermediate pressure flow path) are simultaneously employed, thereby making it possible to solve the conventional problem (reduced durability of the pressure sensing section due to pressure fluctuations in the primary side pressure). The pressure fluctuation damping means (1) (circumferentially extending gap) forms a circumferentially extending gap Gc (see FIG. 4(a)) between the outer peripheral surface of the piston portion 140b and the inner peripheral surface of the main valve guide hole 105b, as shown in FIG. 2, and the pressure fluctuation damping means (2) (circumferentially extending gap at the most upstream side of the intermediate pressure flow path) constantly communicates between the main valve chamber 125 and the back pressure chamber 105c only via the circumferentially extending gap Gc, as shown in FIG. 1.

[0022] <About the main valve body> The main valve body 105 is a hollow cylindrical member made of a metal material such as stainless steel, and has a through hole that passes through along the axis Lm of the main valve portion 100a (hereinafter, in the description of the main valve portion 100a, simply referred to as the "axis Lm"), and this through hole is provided with a main valve port 112 that connects to the second joint pipe 2, an annular main valve seat 105a formed at the other end of the main valve port 112, a main valve chamber 125 that has an inner diameter larger than that of the main valve port 112, a main valve guide hole 105b, and a back pressure chamber 105c that are mutually connected.

[0023] The main valve body 105 also has a through-hole that penetrates radially from the main valve chamber 125, and this through-hole is provided with a main valve inlet port 111 (inlet port) that connects to the first joint pipe 1. The main valve body 105 also has a through-hole that penetrates radially from the back pressure chamber 105c, and this through-hole is provided with a pressure equalizing port 113 that connects to a communication passage 114 of the third joint pipe 3. In addition, the main valve body 105 has a female thread portion 105d on the inner peripheral side of the other end, and this female thread portion 105d is threadedly engaged with a male thread portion 162a on the outer peripheral side of the adjustment screw cover body 162 so as to be movable in the direction of the axis Lm. The back pressure chamber 105c is sealed via this threaded portion.

[0024] <About the main valve> The main valve element 140 includes a substantially cylindrical main valve seat 140a provided on one side, a cylindrical piston portion 140b extending toward the other side along the axis Lm, and a locking portion 140c extending further from the piston portion 140b toward the other side along the axis Lm. The main valve seat 140a is made of a resin material such as PTFE and is disposed so as to cover the main valve seat 105a when viewed along the axis Lm. The piston portion 140b and the locking portion 140c are made of a metal material such as brass. The piston portion 140b is disposed within the main valve guide hole 105b so as to be guided along the axis Lm. A main valve spring 163 is sandwiched between the other end of the piston portion 140b and one end of the adjusting screw cover 162, so that the main valve element 140 is constantly biased in the valve closing direction (see Fm in FIG. 2).

[0025] Movement of the main valve element 140 in the direction of the axis Lm is caused by factors such as the pressure difference between the primary pressure P1 and the intermediate pressure P1' (P1'≦P1), the pressure difference between the primary pressure P1 and the secondary pressure P2, and the biasing force of the main valve spring 163 (see Fm in FIG. 2), as will be described in detail later. These external forces cause the main valve element 140 to move toward or away from the main valve seat 105a, thereby determining the valve opening. Here, as will be described in detail later, the engagement portion 140c comes into contact with the main valve element stopper portion 162b of the adjusting screw cover 162, thereby determining the maximum valve lift of the main valve element 140 from the valve closed state to the valve fully open state, which is the maximum valve lift state.

[0026] Furthermore, leaf springs 191 are attached at equal intervals in the circumferential direction to surround the locking portion 140c at the other end of the main valve body 140. These leaf springs 191 are made of a metal material such as stainless steel or phosphor bronze, and are formed by pressing a relatively thin, elastic member, and as shown in Fig. 2, when the curved portion comes into contact with the inner peripheral surface of the back pressure chamber 105c, the leaf springs 191 bend, generating an urging force.

[0027] <Main valve spring unit> The main valve spring unit 160 is composed of an adjustment screw cover body 162 and a main valve spring 163 that is sandwiched between one end of the adjustment screw cover body 162 and the other end of the piston portion 140b. The adjustment screw cover body 162 is made of a metal material such as stainless steel, and is provided at one end with a main valve element stopper portion 162b that extends to one side in the direction of the axis Lm. A male thread portion 162a is provided on the outer periphery of the adjustment screw cover body 162, and is threadedly engaged with a female thread portion 105d provided on the inner periphery of the main valve body 105 so as to be movable in the direction of the axis Lm. This allows the biasing force of the main valve spring 163 to be adjusted, thereby adjusting the pressure at which the main valve element 140 opens (valve opening pressure Pmo (=relief pressure Pre) of the main valve portion 100a) (see FIG. 5).

[0028] <Pilot Division Structure> 1 and 3, the pilot section 200a is mainly composed of a pilot main body 205, a pilot valve seat member 230, a pilot valve disc 240, a pressure-sensing unit 250, an adjusting spring unit 260, a lower connecting means 270, and an upper connecting means 280. Each component of the pilot section 200a will be described below in order. In the pilot section 200a, the pilot valve seat member 230, the pilot valve disc 240, the lower connecting means 270, the pressure-sensing unit 250, the upper connecting means 280, and the adjusting spring unit 260 are assembled to the pilot main body 205 in this order, in a state in which they are indirectly engaged from one side to the other. The fluid path direction is from the third joint pipe 3 (fluid path) to the fourth joint pipe 4 (fluid path).

[0029] <About the Pilot> The pilot body 205 is composed of a pilot valve housing 210 connected to the third joint pipe 3 and the fourth joint pipe 4, and a spring case 220 joined to the other end of the pilot valve housing 210 by crimping or the like.

[0030] The pilot valve housing 210 is a hollow cylindrical member made of a metal material such as stainless steel, and has a through-hole that passes through along the axis Lp of the pilot section 200a (hereinafter, in the description of the pilot section 200a, simply referred to as the "axis Lp"), and in this through-hole, a pilot outflow port 212 connected to the fourth joint pipe 4, an intermediate chamber 213, and a bellows accommodating chamber (pressure-sensing section accommodating chamber) 216 are provided so as to communicate with each other. An annular one-side spring bearing portion 218 is provided on the inner wall on one end side of the intermediate chamber 213.

[0031] The pilot valve housing 210 further has a through hole that penetrates radially from the intermediate chamber 213, and this through hole is provided with a pilot inlet port 211 that connects to the third joint pipe 3. As a result, in the valve closed state, an intermediate pressure P1' (≦primary side pressure P1) can be introduced via the pilot inlet port 211 into the intermediate chamber 213, a pilot valve chamber 215 (described later), and a bellows accommodating chamber 216.

[0032] The spring case 220 is made of a metal material such as brass, is a hollow cylindrical member having a through-hole that penetrates along the axis Lp, and is provided with a spring accommodating chamber 221. A female thread portion 222 is provided on the inner peripheral side of the other end of the spring case 220, and is threadedly engaged with a male thread portion 262c provided on the outer peripheral side of the adjustment screw member 262 so as to be movable in the direction of the axis Lp. Atmosphere is constantly introduced into the spring accommodating chamber 221 via this threaded portion.

[0033] <Pilot valve seat material> The pilot valve seat member 230 is made of a metal material such as stainless steel, is a hollow cylindrical member having a through-hole that passes through along the axis Lp, and is configured by integrally forming a pilot valve seat portion 231 and a pilot guide portion 232. This pilot valve seat member 230 is press-fitted into the through-hole that passes through one side end of the pilot valve housing 210 in the direction of the axis Lp, and then fixed by brazing.

[0034] The pilot valve seat portion 231 extends along the axis Lp and has a pilot valve port 231a with an annular pilot valve seat 231c formed at the other end, and an internal passage 231b which has an inner diameter larger than that of the pilot valve port 231a and defines the pilot outflow port 212.

[0035] The pilot guide portion 232 is provided in the intermediate chamber 213, has a cylindrical shape erected from the periphery of the other end of the pilot valve seat portion 231, defines the pilot valve chamber 215 on its inner peripheral side, and is provided with four radial communicating holes 232a arranged at equal intervals in the circumferential direction so as to provide radial communication between the pilot valve chamber 215 and the intermediate chamber 213 about the axis Lp. Note that, in this embodiment, the four radial communicating holes 232a are arranged at equal intervals in the circumferential direction, but the number and arrangement of the radial communicating holes 232a are not limited to this, and can be appropriately set depending on the intended use of the pilot portion 200a.

[0036] <About the pilot valve> Pilot valve element 240 is provided on one side and includes a substantially conical pilot valve portion 241 and a cylindrical pilot guide shaft portion 242 extending to the other side in the direction of axis Lp, with the pilot guide shaft portion 242 being disposed on the inner peripheral side of pilot guide portion 232 except for its other end. An annular groove portion 242a is formed on the outer peripheral surface of the other end of this pilot guide shaft portion 242. Here, other-side spring bearing portion 207 is made of a ring-shaped thin plate having multiple protrusions on its inner peripheral side, and is engaged with annular groove portion 242a via these multiple protrusions.

[0037] The pilot guide shaft portion 242 of the pilot valve element 240 is arranged so as to be guided in the direction of the axis Lp within the pilot guide portion 232 of the pilot valve seat member 230. The pilot valve element 240 is constantly biased in the valve opening direction by the valve-opening spring 206 held between the other-side spring bearing portion 207 engaged with the annular groove portion 242a of the pilot valve element 240 and the one-side spring bearing portion 218 of the pilot valve housing 210 (see Fp1 in FIG. 3).

[0038] The movement of the pilot valve element 240 in the direction of the axis Lp is caused by, as will be described in detail later, the pressure difference between the intermediate pressure P1′ (P1′≦P1) and the secondary pressure P2, the biasing forces of the pressure-sensing bellows (pressure-sensing portion) 251 and the adjusting spring 263 acting on the other end of the pilot valve element 240 (see Fp2 and Fp3 in FIG. 3 ), and the biasing force of the valve-opening spring 206 acting on the other-side spring seat 207 (see Fp1 in FIG. 3 ). These external forces cause the pilot valve element 241 to move toward or away from the pilot valve seat 231c, thereby determining the valve opening. Here, as will be described in detail later, the contact of the stepped portion 255c of the connecting rod 255 with the bellows top cover 253 determines the maximum valve lift of the pilot valve element 240 from the valve-closed state to the fully-open state, which is the maximum valve lift state.

[0039] <About the pressure-sensing unit> The pressure sensing unit 250 is composed of a pressure sensing bellows 251, which is a pressure sensing portion, a bellows top cover 253, and a connecting rod 255 having one end and the other end extending along the axis Lp. The one end and the other end of the pressure sensing bellows 251, which extend along the axis Lp, are connected to one end of the connecting rod 255 and the bellows top cover 253, respectively. The elastic force of the pressure sensing bellows 251 itself biases the pilot valve element 240 in the valve closing direction (see Fp2 in FIG. 3). The pressure sensing unit 250 is made of a metal material such as stainless steel, and is housed in the bellows housing chamber 216 of the pilot valve housing 210.

[0040] The pressure-sensing bellows 251 is connected to one end of the connecting rod 255 and the bellows top cover 253, so that an intermediate pressure P1' (P1'≦P1) is constantly introduced into the external space of the pressure-sensing bellows 251 via the intermediate chamber 213 and the bellows accommodating chamber 216. Meanwhile, the atmosphere is constantly introduced into the internal space of the pressure-sensing bellows 251 via a gap formed between the small-diameter portion 255b of the connecting rod 255 and the insertion hole 253a of the bellows top cover 253, and a gap formed between the upper ball 283 and the contact portion 253c of the bellows top cover 253. In addition, the dimensional relationships of the outer diameter of the peaks and the inner diameter of the valleys of the bellows shape of the pressure-sensing bellows 251 are set so that they are constantly out of contact with the pilot valve housing 210 and the connecting rod 255, respectively. The pressure-sensing part in this embodiment is a pressure-sensing bellows 251, but is not limited to this and may be, for example, a diaphragm.

[0041] The connecting rod 255 includes a large-diameter portion 255a having a generally cylindrical shape extending toward one side in the direction of the axis Lp, and a small-diameter portion 255b having a generally cylindrical shape extending from the large-diameter portion 255a toward the other side in the direction of the axis Lp. A flange portion 255d is formed at one end of the large-diameter portion 255a, protruding radially, and to which one end of the pressure-sensing bellows 251 is connected by welding. An annular step portion 255c is formed between the large-diameter portion 255a and the small-diameter portion 255b.

[0042] The bellows top cover 253 extends concentrically along the axis Lp and includes an insertion hole 253a through which the small diameter portion 255b of the connecting rod 255 is inserted, a bellows top cover joint 253b to which the other end of the pressure-sensing bellows 251 is connected, and a cylindrical contact portion 253c that extends concentrically along the axis Lp, has an inner diameter larger than that of the insertion hole 253a, through which the small diameter portion 255b of the connecting rod 255 is inserted and through which the upper ball 283 slides. Here, by welding the other end portions of the bellows top cover 253 and the pilot valve housing 210 to each other, the pressure-sensing unit 250 is fixed to the pilot body 205 so as not to be displaceable relative to it.

[0043] <About the adjustment spring unit> The adjustment spring unit 260 is composed of a spring receiving member 261, an adjustment screw member 262, and an adjustment spring 263 that is sandwiched between the spring receiving member 261 and the adjustment screw member 262 and biases the pilot valve portion 241 in the valve closing direction. The spring receiving member 261 and the adjustment screw member 262 are made of a metal material such as brass and are housed in the spring accommodating chamber 221 of the spring case 220. The spring receiving member 261 includes a boss portion 261a extending on the other side in the direction of the axis Lp, and a flange portion 261b provided on one side in the direction of the axis Lp and on which one end of the adjustment spring 263 sits. The adjustment screw member 262 also includes an annular wall portion 262a extending on one side in the direction of the axis Lp, and an upper surface portion 262b provided on the other side and on which the other end of the adjustment spring 263 sits. A male thread portion 262c is provided on the outer periphery of this adjustment screw member 262, and is threadedly engaged with a female thread portion 222 provided on the inner periphery of the spring case 220 so as to be movable in the direction of the axis Lp. This makes it possible to adjust the biasing force of the adjustment spring 263 and to adjust the pressure at which the pilot valve element 240 opens the valve (valve opening pressure Ppo) (see FIG. 5). Note that in this embodiment, a multiple-wound wave spring is used as the adjustment spring 263, but the present invention is not limited to this and may be, for example, a coil spring.

[0044] <About the bottom connection method> The lower connecting means 270 is composed of a pair of recesses 271, 272 formed on opposing surfaces of the pilot valve element 240 and the pressure sensing unit 250 in the direction of the axis Lp, and a lower ball 273 sandwiched between the pair of recesses 271, 272 to form a concave-convex engagement. The pair of recesses 271, 272 are formed at the axial centers of the other end face of the pilot guide shaft portion 242 and one end face of the large diameter portion 255a, and are composed of a conical lower recess 271 and an upper recess 272. This conical shape has a bottom surface formed concentrically with the axis Lp and a vertex located on the axis Lp. The lower ball 273 is made of a metal material such as stainless steel.

[0045] As a result, the pilot guide shaft portion 242 of the pilot valve element 240 is arranged within the pilot guide portion 232 of the pilot valve seat member 230 so as to be able to be guided along the axis Lp, and therefore the center position of the lower recessed portion 271 is always arranged in the vicinity of the axis Lp. In addition, a centripetal force acts on the upper recessed portion 272 via the lower recessed portion 271 and the lower ball 273, so that the center position of the upper recessed portion 272 is independently arranged in the vicinity of the axis Lp.

[0046] <About the upper connection method> The upper connecting means 280 is composed of a pair of engaging portions 281, 282 formed on opposing surfaces of the connecting rod 255 and the spring receiving member 261 in the direction of the axis Lp, and an upper ball 283 sandwiched between the pair of engaging portions 281, 282 to form a concave-convex engagement. The pair of engaging portions 281, 282 are formed at the axial centers of the other end surface of the small-diameter portion 255b and one end surface of the spring receiving member 261, and are composed of a conical lower engaging portion 281 and an upper engaging portion 282. The conical shape has a bottom surface formed concentrically with the axis Lp and a vertex located on the axis Lp. The upper ball 283 is made of a metal material such as stainless steel.

[0047] Here, as viewed from the direction of the axis Lp, the radius of the circular side portion of the upper ball 283 is set to be slightly smaller than the radius of the contact portion 253c, so the center position of the upper ball 283 is always located near the axis Lp. Also, the centers of the lower engaging portion 281 and the upper engaging portion 282 are independently located near the axis Lp because a centripetal force acts on the lower engaging portion 281 and the upper engaging portion 282 via the upper ball 283, whose movement in the radial direction is restricted. Furthermore, the small diameter portion 255b of the connecting rod 255 is set to be inserted along the axis Lp in a non-contact state into the insertion hole 253a.

[0048] <Regarding the conventional problem (deterioration of the durability of the pressure sensing part due to fluctuations in primary pressure)> 11, the pressure-sensing unit accommodating chamber 1216 in which the reversing plate 1251 is accommodated is constantly in communication with the main valve inlet port 1111 via the internal communication passage 1237, and the reversing plate 1251 is repeatedly subjected to impact pressure due to unsteady pressure fluctuations in the primary pressure P1. As a result, the conventional pilot-operated pressure regulating valve 1100 has the same problem (reduced durability of the pressure-sensing unit due to pressure fluctuations in the primary pressure), which could lead to reduced reliability.

[0049] In contrast to this, in the first embodiment, by simultaneously adopting pressure fluctuation buffering means (1) (circumferentially extending gap) and pressure fluctuation buffering means (2) (circumferentially extending gap at the most upstream of the intermediate pressure flow path), it is possible to resolve the conventional problem (reduced durability of the pressure-sensing part due to pressure fluctuations in the primary side pressure).

[0050] <Operation of the pilot operated pressure regulating valve> 1 to 5, the operation of the pilot-operated pressure regulating valve 300a will be described while showing the pressure fluctuation damping means (1) (circumferentially extending gap) and the pressure fluctuation damping means (2) (circumferentially extending gap at the most upstream of the intermediate pressure flow path). Here, the operation will be described while showing the relational expressions of the external forces acting on the main valve section 100a and the pilot section 200a in the order of State 1, State 2, and State 3 (see FIG. 5). Here, the pilot-operated pressure regulating valve 300a will be described as being used in a refrigerant circuit, but is not limited thereto. As shown in FIG. 1, in the main valve section 100a, the main valve inlet port 111 is connected to the first joint pipe 1 on the high-pressure (primary pressure P1) side, the main valve port 112 is connected to the second joint pipe 2 on the low-pressure (secondary pressure P2) side, and the pressure equalizing port 113 is connected to the third joint pipe 3 on the intermediate pressure P1′ side. In the pilot section 200a, the pilot inlet port 211 is connected to the third joint pipe 3 at the intermediate pressure P1', and the pilot valve port 231a is connected to the fourth joint pipe 4 at the low pressure (secondary pressure P2). This fourth joint pipe 4 is connected to the second joint pipe 2 via a T-joint. Furthermore, as shown by the dashed line (Flow) in FIG. 2, the working fluid in the pilot operated pressure regulating valve 300a is introduced from the first joint pipe 1 through the main valve inlet port 111 into the main valve chamber 125, passes through the circumferentially extending gap Gc, reaches the back pressure chamber 105c, the pressure equalizing port 113, and the communicating passage 114, and is introduced into the bellows accommodating chamber 216 via the pilot inlet port 211 and the intermediate chamber 213, as shown by the dashed line (Flow) in FIG.

[0051] (Condition 1: When the primary pressure is lower than the pilot valve opening pressure) As shown in FIG. 5(b), in the pilot-operated pressure regulating valve 300a, when the primary-side pressure P1 is lower than the valve-opening pressure Ppo (<relief pressure Pre) of the pilot section 200a, the main valve section 100a and the pilot section 200a are each in a valve-closed state (see FIGS. 4(a) and 4(b)). As a result, the flow rate Q of the working fluid passing through the pilot-operated pressure regulating valve 300a is 0. Furthermore, as shown in FIG. 1, the flows in the back pressure chamber 105c, the communicating passage 114, and the bellows accommodating chamber 216 are generally stagnant, so the pressure P1' in this space (hereinafter referred to as the "intermediate pressure") is equalized to the primary-side pressure P1 in the main valve chamber 125 via the circumferentially extending gap Gc (P1' = P1) (see FIG. 5(a)).

[0052] <Regarding the pressure fluctuation damping means (1) (circumferentially extending gap)> As shown in FIG. 4( a), the pressure fluctuation damping means (1) (circumferentially extending gap Gc) in this embodiment is a gap (hereinafter referred to as the “circumferentially extending gap”) Gc formed between the outer peripheral surface of the piston portion 140b and the inner peripheral surface of the main valve guide hole 105b. When the circumferentially extending gap Gc in this embodiment and the interior communicating passage 1237 of the conventional pilot operated pressure regulating valve 1100 are compared assuming that they have the same flow path area, the circumferentially extending gap Gc in this embodiment has an extremely narrow opposing surface distance in a direction perpendicular to the flow direction compared to the interior communicating passage 1237 of the conventional pilot operated pressure regulating valve 1100. As a result, when pressure waves caused by pressure fluctuations in the primary side pressure P1 pass through the circumferentially extending gap Gc, they repeatedly collide with the pair of opposing surfaces of the circumferentially extending gap Gc extremely frequently, thereby efficiently damping the pressure fluctuation. In State 1, there is almost no flow of working fluid itself through the circumferentially extending gap Gc, and mainly pressure waves are transmitted through the circumferentially extending gap Gc. Therefore, there may be a state where a gap that is not continuous in the circumferential direction is created between the outer peripheral surface of the piston portion 140b and the inner peripheral surface of the main valve guide hole 105b, but is discontinuous in the circumferential direction due to partial contact. However, even in this state, the circumferentially extending gap Gc can efficiently buffer pressure fluctuations.

[0053] Here, the opening area in the circumferentially extending gap Gc in the present embodiment can take an extremely small value, for example, from 0.001 to 7.0 (mm 2 ), and preferably from 0.016 to 1.877 (mm 2 ).

[0054] <Regarding the pressure fluctuation buffering means (2) (circumferentially extending gap at the most upstream of the intermediate pressure flow path)> As shown in FIG. 1, the pressure fluctuation buffering means (2) (circumferentially extending gap at the most upstream of the intermediate pressure flow path) in the present embodiment always connects the main valve chamber 125 and the back pressure chamber 105c to the bellows housing chamber 216 only through the circumferentially extending gap Gc. Thereby, the circumferentially extending gap Gc is provided on the most upstream side in the flow path (hereinafter referred to as the "intermediate pressure flow path") up to the back pressure chamber 105c, the communication path 114, and the bellows housing chamber 216, which becomes the intermediate pressure P1'. For this reason, since the pressure wave buffered by the pressure fluctuation buffering means (1) (circumferentially extending gap Gc) needs to pass through the entire length of the intermediate pressure flow path from the back pressure chamber 105c to the bellows housing chamber 216 via the communication path 114, the pressure fluctuation can be further buffered.

[0055] (Regarding the relational expression of the external force acting on the main valve portion in state 1) Here, the relational expression of the external force acting on the main valve portion 100a in state 1 will be described. As shown in FIG. 2, on the main valve body 140, as forces acting in the direction in which the main valve seat 140a opens, the secondary side pressure P2 × the pressure receiving area Sm2 and the primary side pressure P1 × the pressure receiving area (Sm1 - Sm2) are generated. On the other hand, as forces acting in the direction in which the main valve seat 140a closes, the intermediate pressure P1' × the pressure receiving area Sm1 and the biasing force Fm of the main valve spring 163 are generated.

[0056] Therefore, the relational expression of the external force acting on the main valve seat 140a of the main valve portion 100a can be expressed as follows. P2 × Sm2 + P1 × (Sm1 - Sm2) < P1' × Sm1 + Fm (Equation 1) Here, P1: primary side pressure [N / mm 2 ​ P2: Secondary pressure [N / mm 2 P1’: Intermediate pressure [N / mm 2 Sm1: Pressure receiving area of piston part 140b [mm 2 Sm2: Pressure receiving area of main valve seat 140a [mm 2 Fm: Biasing force of main valve spring 163 [N] Note that the pressure receiving area Sm1 of the piston part 140b is the pressure receiving area calculated based on the outer diameter Dm1 of the piston part 140b, and the pressure receiving area Sm2 of the main valve seat 140a is the pressure receiving area calculated based on the diameter Dm2 of the main valve port 112 (Sm1 > Sm2).

[0057] Also, when substituting P1’ = P1 into (Equation 1), it can be arranged as follows. (P2 - P1) × Sm2 < Fm (Equation 2)

[0058] In (Equation 2), since P1 > P2, the left side becomes a negative value. Therefore, in the main valve part 100a, even if the biasing force Fm of the main valve spring 163 does not exist, the valve closed state can be maintained by the differential pressure between the primary pressure P1 and the secondary pressure P2 (see Fig. 4(a)).

[0059] (Regarding the relational expression of the external force acting on the pilot part in State 1) Here, the relational expression of the external force acting on the pilot part 200a in State 1 will be described. As shown in Fig. 3, on the pilot valve body 240, as forces acting in the valve opening direction of the pilot valve part 241, there are the secondary pressure P2 × pressure receiving area Sp2, the biasing force Fp1 of the valve opening spring 206, and, via the pressure sensitive bellows 251, the intermediate pressure P1’ × pressure receiving area Sp1. On the other hand, as forces acting in the valve closing direction of the pilot valve part 241, there are the intermediate pressure P1’ × pressure receiving area Sp2, the biasing force Fp2 of the pressure sensitive bellows 251 itself, and the biasing force Fp3 of the adjusting spring 263.

[0060] ​​​​Therefore, the relational expression of the external force acting on the pilot valve portion 241 of the pilot portion 200a can be expressed as follows. P1’×Sp1+P2×Sp2+Fp1<P1’×Sp2+Fp2+Fp3 (Equation 3) Here, P1’: intermediate pressure [N / mm 2 P2: secondary side pressure [N / mm 2 Sp1: effective pressure receiving area of the pressure-sensitive bellows 251 [mm 2 Sp2: pressure receiving area of the pilot valve portion 241 [mm 2 Fp1: biasing force of the valve opening spring 206 [N] Fp2: biasing force by the pressure-sensitive bellows 251 itself [N] Fp3: biasing force of the adjustment spring 263 [N] Note that the effective pressure receiving area Sp1 of the pressure-sensitive bellows 251 is the pressure receiving area calculated based on the average inner diameter Dp1 of the minimum inner diameter and the maximum inner diameter of the bellows shape, and the pressure receiving area Sp2 of the pilot valve portion 241 is the pressure receiving area calculated based on the diameter Dp2 of the pilot valve port 231a.

[0061] (Equation 3) can be rearranged to P1’×Sp1+Fp1<(P1’-P2)×Sp2+Fp2+Fp3.

[0062] Dividing both sides of this equation by Sp1, it can be transformed into P1’+Fp1 / Sp1<(P1’-P2)×Sp2 / Sp1+(Fp2+Fp3) / Sp1. Here, since the ratio of the pressure receiving area Sp2 of the pilot valve portion 241 to the effective pressure receiving area Sp1 of the pressure-sensitive bellows 251 is extremely small (Sp1>>Sp2), the first term on the right side can be ignored, and as a result, the influence of the fluctuation of the secondary side pressure P2 can be made extremely small.

[0063] Therefore, the above equation can be rearranged as follows. P1’×Sp1<Fp2+Fp3-Fp1 (Equation 4)

[0064] ​​​​Also, in state 1, since P1’ = P1, substituting this relationship into (Equation 4) allows for further rearrangement as follows. P1 × Sp1 < Fp2 + Fp3 - Fp1 (Equation 5)

[0065] The biasing force Fp3 of the adjusting spring 263 is set so that (Equation 5) is satisfied and the valve-closed state of the pilot portion 200a is maintained.

[0066] (State 2: When the primary-side pressure is higher than the valve-opening pressure of the pilot portion and lower than the valve-opening pressure of the main valve portion) As shown in FIG. 5(b), in the pilot-operated pressure regulating valve 300a, when the primary-side pressure P1 is higher than the valve-opening pressure Ppo of the pilot portion 200a and lower than the valve-opening pressure Pmo (= relief pressure Pre) of the main valve portion 100a, the main valve portion 100a is in the valve-closed state (see FIG. 4(c)), while the pilot portion 200a is in the valve-open state (see FIG. 4(d)). At this time, the pilot valve body of the pilot portion 200a moves in the valve-opening direction (see the arrow M1 in FIG. 4(d)). As a result, when the working fluid passing through the pilot-operated pressure regulating valve 300a passes through the circumferentially extending gap Gc of the main valve portion 100a, as shown in FIG. 5(a), there is a pressure loss to an intermediate pressure P1’ that is lower than the primary-side pressure P1. Therefore, as shown in FIG. 5(b), the flow rate Q of the pilot-operated pressure regulating valve 300a has a gentle increasing trend as the intermediate pressure P1’ also increases with the increase in the primary-side pressure P1 (P1’ < P1).

[0067] Also, similar to State 1, by simultaneously adopting the pressure fluctuation buffering means (1) (circumferentially extending gap Gc) and the pressure fluctuation buffering means (2) (circumferentially extending gap at the most upstream of the intermediate pressure flow path), when the pressure wave passes through the circumferentially extending gap Gc and when it passes through the entire length of the intermediate pressure flow path from the back pressure chamber 105c to the bellows housing chamber 216 via the communication passage 114, the pressure fluctuation can be reliably buffered. In particular, in State 2, since there is a flow of the working fluid through the circumferentially extending gap Gc, the main valve body 140 moves to the central position of the axis Lm, and a circumferentially continuous gap is formed and maintained between the main valve body 140 and the main valve guide hole 105b. Therefore, when the pressure wave due to the pressure fluctuation of the primary side pressure P1 passes through this circumferentially continuous gap, the pressure fluctuation can be buffered more efficiently.

[0068] (Regarding the relational expression of the external force acting on the main valve portion in State 2) Here, the relational expression of the external force acting on the main valve portion 100a in State 2 will be described. In the main valve portion 100a, the difference between State 2 and State 1 is only that the intermediate pressure P1' is lower than the primary side pressure P1. Therefore, the relational expression of the external force acting on the main valve portion 100a in State 2 is shown as the aforementioned (Equation 1), and (Equation 1) can be further arranged as follows. (P1 - P1') × Sm1 + (P2 - P1) × Sm2 < Fm (Equation 6)

[0069] (Regarding the relational expression of the external force acting on the pilot portion in State 2) Here, the relational expression of the external force acting on the pilot portion 200a in State 2 will be described. In the pilot portion 200a, the difference between State 2 and State 1 is that it has changed from the valve closed state to the valve open state. Therefore, the relational expression of the external force acting on the pilot portion 200a in State 2 has the opposite direction of the inequality sign in the aforementioned (Equation 4). P1' × Sp1 > Fp2 + Fp3 - Fp1 (Equation 7)

[0070] Here, when both sides of (Equation 7) are divided by Sp1, it can be further arranged as follows. P1'>(Fp2+Fp3-Fp1) / Sp1 (Equation 8)

[0071] Since P1'=P1 (see FIG. 5(a)) until pilot section 200a starts to open, valve opening pressure Ppo of pilot section 200a is expressed as (Fp2+Fp3-Fp1) / Sp1. Therefore, by moving adjustment screw member 262 in the direction of axis Lp and appropriately setting biasing force Fp3 of adjustment spring 263, valve opening pressure Ppo of pilot section 200a can be adjusted.

[0072] (Condition 3: When the primary pressure is higher than the main valve opening pressure) As shown in Fig. 5(b), in the pilot-operated pressure regulating valve 300a, when the primary pressure P1 is higher than the valve opening pressure Pmo (=relief pressure Pre) of the main valve section 100a, the main valve section 100a and the pilot section 200a are each in a valve open state (see Figs. 4(e) and 4(f)). At this time, first, the pilot valve element 240 of the pilot section 200a moves further in the valve opening direction (see arrow M2 in Fig. 4(f)), causing the main valve element 140 of the main valve section 100a to move in the valve opening direction (see arrow M3 in Fig. 4(e)). As a result, the locking portion 140c abuts against the main valve element stopper portion 162b, and the valve fully open state of the main valve element 140 is maintained. As a result, the working fluid passing through the pilot-operated pressure regulating valve 300a transitions from flowing through the pilot portion 200a to flowing through the main valve portion 100a, and the flow rate Q of the pilot-operated pressure regulating valve 300a tends to increase rapidly as the primary pressure P1 increases, as shown in FIG. 5(b). In State 3, as in State 2, the working fluid flows through the circumferentially extending gap Gc, so the main valve element 140 moves to the center position of the axis Lm, and a circumferentially continuous gap is formed and maintained between the main valve element 140 and the main valve guide hole 105b. In State 3, the working fluid flows mainly through the main valve port 112 of the main valve portion 100a. Therefore, compared to State 2, in which the working fluid flows only through the pilot valve port 231a of the pilot portion 200a, fluctuations in the primary pressure P1 have significantly less effect on the pressure-sensing bellows 251.

[0073] (Relationship between the external forces acting on the main valve in state 3) Here, we will explain the relational expression of the external force acting on the main valve portion 100a in State 3. State 3 differs from State 2 in that the main valve portion 100a changes from a valve-closed state to a valve-open state. Therefore, the relational expression of the external force acting on the main valve portion 100a in State 3 has the inequality sign in the opposite direction to that in Equation 6 above. (P1-P1')×Sm1+(P2-P1)×Sm2>Fm (Formula 9)

[0074] Therefore, by moving the adjustment screw cover body 162 in the direction of the axis Lm and appropriately setting the biasing force Fm of the main valve spring 163, the valve opening pressure Pmo (=relief pressure Pre) of the main valve portion 100a can be adjusted.

[0075] (Regarding the relational expression for the external force acting on the pilot part in state 3) Here, we will explain the relational expression of the external force acting on the pilot section 200a in State 2. In the pilot section 200a, State 3 differs from State 2 only in the valve opening degree. Therefore, the relational expression of the external force acting on the pilot section 200a in State 3, like State 2, is expressed by the above-mentioned (Equation 8).

[0076] As described above, in the first embodiment, by simultaneously employing the pressure fluctuation damping means (1) (circumferentially extending gap) and the pressure fluctuation damping means (2) (circumferentially extending gap at the most upstream of the intermediate pressure flow path), it is possible to reliably damp pressure fluctuations when the pressure wave passes through the circumferentially extending gap Gc and when it passes through the entire length of the intermediate pressure flow path from the back pressure chamber 105c, via the communicating passage 114, to the bellows accommodating chamber 216. This makes it possible to suppress the repeated application of impact pressure due to a sudden rise in pressure, etc. to the pressure-sensing bellows 251, and to solve the conventional problem (reduced durability of the pressure-sensing part due to pressure fluctuations in the primary side pressure).

[0077] Furthermore, through extensive research, the inventors have attempted to further dampen pressure fluctuations in the bellows accommodating chamber 216 by further examining the configurations of the pressure fluctuation damping means (1) (circumferentially extending gap) and the pressure fluctuation damping means (2) (circumferentially extending gap at the most upstream side of the intermediate pressure flow path).

[0078] <Considerations on pressure fluctuation damping means (1) (circumferentially extending gap)> Here, in the pressure fluctuation damping means (1) (circumferentially extending gap), when the pressure wave passes through the circumferentially extending gap Gc, the pressure wave collides with various obstacles, further damping the pressure fluctuation. The pressure fluctuation damping means (1-1) (uneven portions on the surface defining the circumferentially extending gap), the pressure fluctuation damping means (1-2) (multiple circumferential grooves on the surface defining the circumferentially extending gap), and the pressure fluctuation damping means (1-3) (the circumferentially extending gap is maintained by a biasing means) are shown.

[0079] <Regarding the pressure fluctuation damping means (1-1) (uneven portions on the surfaces defining the circumferentially extending gap)> As shown in FIG. 2 , the pressure fluctuation damping means (1-1) (unevenness on the surface defining the circumferentially extending gap) is an unevenness provided on the surface defining the circumferentially extending gap Gc, i.e., the outer circumferential surface of the piston portion 140b of the main valve element 140 and / or the inner circumferential surface of the main valve guide hole 105b. Specifically, when a pressure wave caused by a pressure fluctuation of the primary pressure P1 passes through the circumferentially extending gap Gc, it collides with the unevenness, resulting in more repeated collisions than with a simple curved surface, and therefore, pressure fluctuations can be damped more efficiently. Note that the unevenness in this embodiment includes not only unevenness provided on the surface defining the circumferentially extending gap Gc, but also C-shaped grooves, spiral grooves, grooves extending in the direction of the axis Lm, grooves inclined with respect to the direction of the axis Lm, multiple recesses, and multiple protrusions. The uneven portion of this embodiment also includes one in which an annular groove is formed on one of the surfaces defining the circumferential gap Gc, and a C-shaped ring housed in this annular groove protrudes toward the other side.Furthermore, the uneven portion of this embodiment also includes one in which an annular groove is formed on one of the surfaces defining the circumferential gap Gc, and an O-ring housed in this annular groove protrudes toward the other side, and the other side is provided with a groove (functioning as a bleed) extending or inclined in the direction of the axis Lm.

[0080] <Regarding the pressure fluctuation damping means (1-2) (plurality of circumferential grooves on the surface defining the circumferentially extending gap)> As shown in FIG. 2, the pressure fluctuation damping means (1-2) (plurality of circumferential grooves on the surface defining the circumferentially extending gap) is a plurality of circumferential grooves provided on the surface defining the circumferentially extending gap Gc, i.e., on the outer circumferential surface of the piston portion 140b of the main valve element 140 and / or the inner circumferential surface of the main valve guide hole 105b. Specifically, pressure waves caused by pressure fluctuations in the primary pressure P1 collide with these circumferential grooves as they pass through the circumferentially extending gap Gc, resulting in more repeated collisions compared to a simple curved surface, and therefore more efficient damping of pressure fluctuations. Furthermore, providing multiple circumferential grooves on the surface defining the circumferentially extending gap Gc is easier to process and allows for lower costs compared to providing uneven portions.

[0081] <Regarding the pressure fluctuation damping means (1-3) (maintaining the circumferentially extending gap by the biasing means)> In States 2 and 3, as described above, the working fluid flows through the circumferentially extending gap Gc, so the main valve element 140 moves to the center position of the axis Lm, and a circumferentially continuous gap is formed and maintained between the main valve element 140 and the main valve guide hole 105b. Because turbulence occurs in the working fluid passing through this circumferentially continuous gap, this turbulence causes the main valve element 140 to oscillate slightly relative to the main valve guide hole 105b as viewed from the direction of the axis Lm. Therefore, although the circumferentially extending gap Gc is circumferentially continuous, there is a risk that it will become an unsteady gap.

[0082] Therefore, the inventors have adopted a pressure fluctuation damping means (1-3) (maintaining the circumferentially extending gap by a biasing means) so that the circumferentially extending gap Gc is a circumferentially continuous and steadily uniform gap mainly in states 2 and 3. As shown in FIG. 2, this pressure fluctuation damping means (1-3) (maintaining the circumferentially extending gap by a biasing means) is a leaf spring 191 (biasing means) that is provided between the main valve element 140 and the inner peripheral surface (slide guide surface) of the back pressure chamber 105c and biases the axis of the main valve element 140 along the axis Lm. The inner peripheral surface of the back pressure chamber 105c is formed concentrically with the axis Lm. The leaf springs 191 are provided at equal intervals in the circumferential direction, and the elastic force of the leaf springs 191 can suppress oscillation of the main valve element 140. As a result, the circumferentially extending gap Gc can be made a circumferentially continuous and steadily uniform gap. Furthermore, as shown in FIG. 5(b), when the pressure repeatedly fluctuates in the boundary region between State 2 and State 3, that is, when the primary pressure P1 is near the relief pressure Pre, the main valve element 140 moves in small increments along the axis Lm, which can cause chattering, resulting in repeated collisions with the main valve seat 105a. In contrast, providing the leaf springs 191 on the main valve element 140 can provide stable sliding resistance to the movement of the main valve element 140 along the axis Lm, thereby suppressing chattering and maintaining a desired valve opening flow rate in the main valve section 100a with a stable valve open position of the main valve element 140. Although the biasing means in this embodiment is the leaf spring 191, it is not limited to this and may be, for example, a C-shaped ring, a ring spring, or the like.

[0083] <Considerations on pressure fluctuation damping means (2) (circumferentially extending gap at the most upstream of the intermediate pressure flow path)> Here, the pressure fluctuation damping means (2) (circumferentially extending gap at the most upstream of the intermediate pressure flow path) is shown as a pressure fluctuation damping means (2') (bent portion of the intermediate pressure flow path) that further damps pressure fluctuations by passing the pressure wave through the entire length of the intermediate pressure flow path from the back pressure chamber 105c, via the connecting passage 114, to the bellows accommodating chamber 216.

[0084] <Regarding the pressure fluctuation damping means (2') (bent portion of the intermediate pressure flow path)> 1 and 2, the pressure fluctuation damping means (2') (bent portion of the intermediate pressure flow path) is a bent portion Bp provided in the intermediate pressure flow path leading from the back pressure chamber 105c to the communicating path 114. Specifically, when a pressure wave propagates from the back pressure chamber 105c to the communicating path 114, the pressure wave first collides with the adjusting screw cover 162 due to the bent portion Bp, where the flow path is bent by 90 degrees, and then repeats collisions within the back pressure chamber 105c, and finally propagates in a damped state to the communicating path 114. As a result, the pressure wave can be more efficiently damped by the bent portion Bp in the back pressure chamber 105c.

[0085] Although one bent portion Bp in this embodiment is provided between the back pressure chamber 105c and the communicating passage 114, the present invention is not limited thereto, and at least one may be provided at any position in the intermediate pressure flow path extending from the back pressure chamber 105c to the bellows accommodating chamber 216 via the communicating passage 114. Furthermore, although the bent portion Bp in this embodiment bends the flow path by 90 degrees, the present invention is not limited thereto, and the present invention may be any flow path that bends by at least 90 degrees or more, such as a flow path that bends by 180 degrees.

[0086] As described above, in the first embodiment, by simultaneously adopting the pressure fluctuation buffering means (1) (circumferentially extending gap) and the pressure fluctuation buffering means (2) (circumferentially extending gap at the most upstream of the intermediate pressure flow path), it is possible to solve the conventional problem (reduced durability of the pressure-sensing part due to pressure fluctuations in the primary side pressure) and improve reliability.

[0087] In the first embodiment, the pressure fluctuation damping means (1) (circumferentially extending gap) is improved by employing the pressure fluctuation damping means (1-1) (unevenness on the surface defining the circumferentially extending gap) or the pressure fluctuation damping means (1-2) (plurality of circumferential grooves on the surface defining the circumferentially extending gap). In addition, by employing the pressure fluctuation damping means (1-3) (maintaining the circumferentially extending gap by a biasing means), the circumferentially extending gap Gc becomes a circumferentially continuous and steadily uniform gap, and chattering is suppressed, making it possible to maintain a desired valve opening flow rate in the main valve portion 100a.

[0088] Furthermore, in the first embodiment, the pressure fluctuation damping means (2) (circumferentially extending gap at the most upstream of the intermediate pressure flow path) is devised, and by adopting the pressure fluctuation damping means (2') (bent portion of the intermediate pressure flow path), pressure fluctuations can be damped more efficiently in the back pressure chamber 105c.

[0089] (Second embodiment) A pilot operated pressure regulating valve 300b according to a second embodiment of the present invention will be described using Figure 6. The pilot operated pressure regulating valve 300b of the second embodiment differs from the pilot operated pressure regulating valve 300a of the first embodiment in that the main valve body 105 and the pilot valve housing 210 are directly connected and the third joint pipe 3 and the fourth joint pipe 4 are omitted, but the other basic configuration is the same as that of the first embodiment. Here, the same members are given the same reference numerals and redundant explanations will be omitted.

[0090] As shown in FIG. 1, the pilot-operated pressure regulating valve 300a of the first embodiment requires, in particular, a third joint pipe 3 that connects the main valve section 100a and the pilot section 200a, a fourth joint pipe 4 that connects the pilot section 200a and the second joint pipe 2, an L-shaped joint, a T-shaped joint, and the like. This increases the number of parts, raising concerns about increased inventory management costs, and also about the need to secure a relatively large installation space due to the need to route the third joint pipe 3 and the fourth joint pipe 4.

[0091] In contrast to this, the pilot type pressure regulating valve 300b according to the second embodiment employs a third fluid path 3' (fluid path) and a fourth fluid path 4' (fluid path) formed between the main valve body 105 and the pilot valve housing 210, instead of the third joint pipe 3 and the fourth joint pipe 4 of the first embodiment. As a result, the pilot type pressure regulating valve 300b according to the second embodiment has fewer parts, lower costs, saves space, and improves portability, compared to the pilot type pressure regulating valve 300a according to the first embodiment.

[0092] As described above, in the second embodiment, similarly to the first embodiment, by simultaneously employing pressure fluctuation buffering means (1) (circumferentially extending gap) and pressure fluctuation buffering means (2) (circumferentially extending gap at the most upstream of the intermediate pressure flow path), it is possible to solve the conventional problem (reduced durability of the pressure-sensing part due to pressure fluctuations in the primary side pressure) and improve reliability.

[0093] In the second embodiment, similarly to the first embodiment, pressure fluctuations can be more efficiently damped by employing pressure fluctuation damping means (1-1) (concave and recessed portions on the surface defining the circumferentially extending gap) or pressure fluctuation damping means (1-2) (plurality of circumferential grooves on the surface defining the circumferentially extending gap). Furthermore, by employing pressure fluctuation damping means (1-3) (maintaining the circumferentially extending gap with a biasing means), chattering can be suppressed and a desired valve opening flow rate in the main valve portion 100b can be maintained. In addition, by employing pressure fluctuation damping means (2') (bent portion of the intermediate pressure flow path), pressure fluctuations can be more efficiently damped in the back pressure chamber 105c.

[0094] Furthermore, in the second embodiment, by adopting a third fluid path 3' and a fourth fluid path 4' formed between the main valve body 105 and the pilot valve housing 210, the number of parts can be reduced, costs can be reduced, space can be saved, and portability can be improved.

[0095] (Third embodiment) A pilot-operated pressure regulating valve 300c according to a third embodiment of the present invention will be described using Figure 7. In the third embodiment, a common valve body 110c is used for a main valve section 100c and a pilot section 200c, which are integrally configured, and the axis Lm of the main valve section 100c is disposed so as to be perpendicular to the axis Lp of the pilot section 200c. However, the other basic configuration is the same as that of the second embodiment. Here, the same members are denoted by the same reference numerals, and duplicated explanations will be omitted.

[0096] As shown in FIG. 6, the pilot-operated pressure regulating valve 300b of the second embodiment can reduce the number of parts, thereby reducing costs and saving space. However, there was a concern that the third fluid path 3′ formed between the main valve body 105 and the pilot valve housing 210 would be shorter than in the first embodiment.

[0097] In contrast, in a pilot-operated pressure regulating valve 300c according to a third embodiment, the axis Lm of the main valve section 100c is arranged so as to be perpendicular to the axis Lp of the pilot section 200c. As a result, in the third embodiment, the flow path length of the third fluid path 3', i.e., the intermediate pressure flow path length, can be made longer compared to the second embodiment, and the flow path at the bend section Bp can be bent 180°. Therefore, similar to the second embodiment, in addition to lower costs, saving space, and improving portability, pressure fluctuations can be more efficiently damped.

[0098] As described above, in the third embodiment, similarly to the second embodiment, by simultaneously employing pressure fluctuation buffering means (1) (circumferentially extending gap) and pressure fluctuation buffering means (2) (circumferentially extending gap at the most upstream of the intermediate pressure flow path), it is possible to solve the conventional problem (reduced durability of the pressure-sensing part due to pressure fluctuations in the primary side pressure) and improve reliability.

[0099] In the third embodiment, similarly to the second embodiment, pressure fluctuations can be more efficiently damped by employing pressure fluctuation damping means (1-1) (concave and recessed portions on the surface defining the circumferentially extending gap) or pressure fluctuation damping means (1-2) (plurality of circumferential grooves on the surface defining the circumferentially extending gap). Furthermore, by employing pressure fluctuation damping means (1-3) (maintaining the circumferentially extending gap with a biasing means), chattering can be suppressed and a desired valve opening flow rate can be maintained in the main valve portion 100c. In addition, by employing pressure fluctuation damping means (2') (bent portion of the intermediate pressure flow path), pressure fluctuations can be more efficiently damped in the back pressure chamber 105c.

[0100] Furthermore, in the third embodiment, by ensuring the length of the intermediate pressure flow path and bending the flow path at the bend portion Bp by 180°, the number of parts can be reduced, and in addition to reducing costs, saving space, and improving portability, pressure fluctuations can be more efficiently buffered.

[0101] In the third embodiment, the main valve section 100c and the pilot section 200c are integrally formed by the valve body 110c, but this is not limited thereto, and for example, the main valve section 100c and the pilot section 200c may be formed separately.

[0102] (Fourth embodiment) A pilot-operated pressure regulating valve 300d according to a fourth embodiment of the present invention will be described using Figure 8. The fourth embodiment differs from the third embodiment mainly in that the axis Lm of the main valve section 100d and the axis Lp of the pilot section 200d are arranged coaxially, but the other basic configurations are the same as those of the third embodiment. Here, the same members are given the same reference numerals, and duplicated explanations will be omitted.

[0103] As shown in FIG. 7, in the pilot-operated pressure regulating valve 300c of the third embodiment, the flow path length of the third fluid path 3′ is increased to ensure the intermediate pressure flow path length, but there is still room to further extend the flow path length of the third fluid path 3′.

[0104] In contrast, in a pilot-operated pressure regulating valve 300d according to a fourth embodiment, the axis Lm of the main valve section 100d and the axis Lp of the pilot section 200d are arranged coaxially, and the valve opening direction of the main valve section and the valve opening direction of the pilot section are arranged opposite to each other. As a result, in the fourth embodiment, the length of the third fluid path 3' (see FIG. 8(b)), i.e., the length of the intermediate pressure flow path, can be made longer than in the third embodiment. Therefore, similar to the third embodiment, in addition to lower costs, space savings, and improved portability, pressure fluctuations can be more efficiently damped.

[0105] As described above, in the fourth embodiment, similarly to the third embodiment, by simultaneously employing pressure fluctuation buffering means (1) (circumferentially extending gap) and pressure fluctuation buffering means (2) (circumferentially extending gap at the most upstream of the intermediate pressure flow path), it is possible to solve the conventional problem (reduced durability of the pressure-sensing part due to pressure fluctuations in the primary side pressure) and improve reliability.

[0106] In the fourth embodiment, similarly to the third embodiment, pressure fluctuations can be more efficiently damped by employing pressure fluctuation damping means (1-1) (concave and recessed portions on the surface defining the circumferentially extending gap) or pressure fluctuation damping means (1-2) (plurality of circumferential grooves on the surface defining the circumferentially extending gap). Furthermore, by employing pressure fluctuation damping means (1-3) (maintaining the circumferentially extending gap by a biasing means), chattering can be suppressed and a desired valve opening flow rate can be maintained in the main valve portion 100d. In addition, by employing pressure fluctuation damping means (2') (bent portion of the intermediate pressure flow path), pressure fluctuations can be more efficiently damped in the back pressure chamber 105c.

[0107] Furthermore, in the fourth embodiment, as in the third embodiment, the length of the intermediate pressure flow path is ensured, and the flow path at the bend portion Bp is bent 180°, thereby reducing the number of parts, reducing costs, saving space, improving portability, and more efficiently cushioning pressure fluctuations.

[0108] In the fourth embodiment, the main valve section 100d and the pilot section 200d are integrally formed by the valve body 110d, but this is not limiting, and for example, the main valve section 100d and the pilot section 200d may be formed separately. Furthermore, in the fourth embodiment, the first joint pipe 1 and the second joint pipe 2 are disposed at symmetrical positions about the axis Lm, Lp as viewed from the direction of the axis Lm, Lp, but this is not limiting, and for example, the first joint pipe 1 and the second joint pipe 2 may be disposed at any circumferential positions as long as they do not intersect with the third fluid path 3' as viewed from the direction of the axis Lm, Lp.

[0109] (Fifth embodiment) A pilot-operated pressure regulating valve 300e according to a fifth embodiment of the present invention will be described using Figure 9. The fifth embodiment differs from the fourth embodiment mainly in that it employs a manifold 120 in which a first fluid path 1' and a second fluid path 2' are formed, and that a pilot valve seat member 230' and a main valve element 140' have a nested structure, but otherwise the basic configuration is the same as that of the fourth embodiment. Here, the same members are given the same reference numerals, and duplicated explanations will be omitted.

[0110] As shown in Fig. 8, in the pilot operated pressure regulating valve 300d of the fourth embodiment, the flow path length of the third fluid path 3' is extended, resulting in a relatively long overall length in the directions of the axes Lm and Lp. Therefore, when the pilot operated pressure regulating valve 300d is connected to the first coupling pipe 1 and the second coupling pipe 2 at the installation site, for example, as shown in Fig. 8, a moment acts on the pilot operated pressure regulating valve 300d, tending to tilt it in a direction perpendicular to the direction in which the first coupling pipe 1 and the second coupling pipe 2 extend, i.e., toward the front or rear of the page. This necessitates a separate support structure for the pilot operated pressure regulating valve 300d. If this support structure were not provided, there would be a risk of damage to the connections between the valve body 110d and the first coupling pipe 1 and the second coupling pipe 2.

[0111] In contrast, the pilot operated pressure regulating valve 300e according to the fifth embodiment employs a manifold 120 in which the first fluid path 1′ and the second fluid path 2′ are formed, thereby improving the strength of the connection between the manifold 120 and the pilot operated pressure regulating valve 300e compared to the fourth embodiment. Furthermore, the pilot operated pressure regulating valve 300e according to the fifth embodiment has a nested structure for the pilot valve seat member 230′ and the main valve element 140′. This reduces the overall length of the pilot operated pressure regulating valve 300e in the directions of the axes Lm and Lp compared to the fourth embodiment, thereby reducing the moment generated when the pilot operated pressure regulating valve 300e tries to tip over. As a result, the pilot operated pressure regulating valve 300e according to the fifth embodiment can suppress damage to the connection between the manifold 120 in which the first fluid path 1′ and the second fluid path 2′ are formed and the valve main body 110e.

[0112] <Configuration of the pilot operated pressure regulating valve> 9 and 10, a pilot-operated pressure regulating valve 300e according to a fifth embodiment of the present invention will be described. The pilot-operated pressure regulating valve 300e is composed of a main valve portion 100e and a pilot portion 200e, and is firmly fixed by crimping or the like to a manifold 120 in which a first fluid path 1' and a second fluid path 2' are formed. From here on, the following description will focus mainly on the differences between the valve body 110e, the main valve portion 100e, and the pilot portion 200e and the fourth embodiment.

[0113] <About the valve body> The valve body 110e is a hollow cylindrical member made of a metal material such as stainless steel and has a through-hole that penetrates along the axes Lm, Lp, and in which a main valve chamber 125, a main valve guide hole 105b, a back pressure chamber 105c, an intermediate chamber 213, and a bellows accommodating chamber 216, which are connected to the first fluid path 1' and the second fluid path 2', respectively, are provided so as to communicate with each other. In addition, a pressure equalizing port 113, a third fluid path 3', and a pilot inlet port 211 are provided at equal intervals circumferentially around the axis Lm, Lp and along the axis Lm, Lp, so as to constantly fluidly connect the back pressure chamber 105c and the intermediate chamber 213.

[0114] <About the main valve body of the main valve section> The main valve element 140' includes a main valve seat 140a' provided on one side and made of a resin material such as PTFE, and a cylindrical piston portion 140b' extending toward the other side along the axis Lm and made of a metal material such as brass. The main valve seat 140a' is accommodated in an annular groove provided on one end of the piston portion 140b' and is fixed via a retaining member 141' (e.g., a C-shaped ring). The piston portion 140b' is disposed so as to cover the main valve seat 105a of the manifold 120 when viewed along the axis Lm. The piston portion 140b' also has a through-hole that passes through along the axis Lm. A main valve element through-hole 140d' and a sliding hole 140e' that define the fourth fluid path 4' are provided in this through-hole and expand in diameter from one end to the other end so as to communicate with each other. Furthermore, a locking portion 140c' is provided at a step between the main valve element through-hole 140d' and the slide hole 140e'. Here, the piston portion 140b' is arranged so as to be able to be guided in the direction of the axis Lm within the main valve guide hole 105b, and the main valve spring 163 is sandwiched between the other end of the piston portion 140b' and the valve body 110e, so that the main valve element 140' is always biased in the valve closing direction.

[0115] With regard to the movement of the main valve element 140' in the direction of the axis Lm, the maximum valve lift amount from the valve closed state of the main valve element 140' to the valve fully open state, which is the maximum valve lift state, is determined by the engagement portion 140c' abutting against the main valve element stopper portion 233' of the pilot valve seat member 230'.

[0116] <Pilot valve seat material> The pilot valve seat member 230' is made of a metal material such as stainless steel, is a hollow cylindrical member having a through-hole that passes through along the axis Lp, and is configured by integrally forming a pilot valve seat portion 231' and a pilot guide portion 232'. This pilot valve seat member 230' is press-fitted into the through-hole that runs along the axis Lp and connects the back pressure chamber 105c of the main valve body 140' and the intermediate chamber 213, and then is fixed by brazing.

[0117] The pilot valve seat portion 231' extends along the axis Lp and has a pilot valve port 231a with an annular pilot valve seat 231c formed at the other end, and a pilot outflow port 212' that has an inner diameter larger than that of the pilot valve port 231a and extends toward one end. An annular groove that accommodates an O-ring 192 (biasing means) is provided on the outer peripheral surface of the pilot valve seat portion 231'. The outer peripheral surface (slide guide surface) of the pilot valve seat portion 231' guides the sliding of the main valve element 140' in the direction of the axis Lm.

[0118] The pilot guide portion 232' has a cylindrical shape that stands upright from the periphery of the other end of the pilot valve seat portion 231', and is provided with a step formed on the outer periphery, which has a one-side spring bearing portion 208. The pilot valve element 240 is constantly urged in the valve opening direction by the valve-opening spring 206 that is sandwiched between this one-side spring bearing portion 208 and the other-side spring bearing portion 207 that engages with the pilot valve element 240.

[0119] <Operation of the pilot operated pressure regulating valve> The operation of the pilot type pressure regulating valve 300e of the fifth embodiment will be described using Fig. 10. In the fifth embodiment, the opening and closing operations of the main valve section 100e and the pilot section 200e in state 1, state 2, and state 3, and the relational expressions between the external forces acting on the main valve section 100e and the pilot section 200e, respectively, are the same as those in the first embodiment, and therefore detailed description thereof will be omitted. In addition, in the fifth embodiment, the pressure fluctuation buffering means (1-1) (uneven portion on the surface defining the circumferentially extending gap) and the pressure fluctuation buffering means (1-2) (plurality of circumferential grooves on the surface defining the circumferentially extending gap) are the same as those in the first to fourth embodiments, and therefore will be mainly described by sequentially showing the pressure fluctuation buffering means (1) (circumferentially extending gap), the pressure fluctuation buffering means (2) (circumferentially extending gap at the most upstream of the intermediate pressure flow path), the pressure fluctuation buffering means (2') (bent portion of the intermediate pressure flow path), and the pressure fluctuation buffering means (1-3) (circumferentially extending gap maintained by the biasing means).

[0120] (Condition 1: When the primary pressure is lower than the pilot valve opening pressure) As shown in Figures 10(a) and (b), in the pilot-type pressure regulating valve 300e, when the primary side pressure P1 is lower than the valve opening pressure Ppo (<relief pressure Pre) of the pilot section 200e, the main valve section 100e and the pilot section 200e are each in a valve closed state.

[0121] <Regarding the pressure fluctuation damping means (1) (circumferentially extending gap)> The pressure fluctuation damping means (1) (circumferentially extending gap Gc) in this embodiment is a circumferentially extending gap Gc formed between the outer peripheral surface of the piston portion 140b' and the inner peripheral surface of the main valve guide hole 105b, as shown in Figure 10(a).When a pressure wave caused by a pressure fluctuation of the primary side pressure P1 passes through the circumferentially extending gap Gc, it repeatedly collides with a pair of opposing surfaces of the circumferentially extending gap Gc very many times, thereby efficiently damping the pressure fluctuation.

[0122] <Regarding the pressure fluctuation damping means (2) (circumferentially extending gap at the most upstream side of the intermediate pressure flow path)> The pressure fluctuation damping means (2) in this embodiment (a circumferentially extending gap at the most upstream of the intermediate pressure flow path) constantly communicates between the main valve chamber 125 and the back pressure chamber 105c only via the circumferentially extending gap Gc, as shown in Fig. 9. Therefore, the circumferentially extending gap Gc is provided at the most upstream side of the intermediate pressure flow path from the back pressure chamber 105c, the third fluid path 3', and the bellows accommodating chamber 216, which are at intermediate pressure P1'. Therefore, the pressure wave damped by the circumferentially extending gap Gc can further damp the pressure fluctuation by passing through the entire length of the intermediate pressure flow path.

[0123] <Regarding the pressure fluctuation damping means (2') (bent portion of the intermediate pressure flow path)> 9, this is a bent portion Bp provided in the intermediate pressure flow path from the back pressure chamber 105c to the third fluid path 3'. Specifically, when a pressure wave propagates from the back pressure chamber 105c to the third fluid path 3', the pressure wave first collides with the valve body 110e due to the bent portion Bp, where the flow path is bent 90 degrees, as it propagates from the back pressure chamber 105c to the third fluid path 3'. After that, the pressure wave repeatedly collides within the back pressure chamber 105c, and finally propagates to the third fluid path 3' in a buffered state. This allows the bent portion Bp to more efficiently buffer pressure fluctuations in the back pressure chamber 105c.

[0124] (Condition 2: When the primary pressure is higher than the valve opening pressure of the pilot valve and lower than the valve opening pressure of the main valve) 10(c) and 10(d), in the pilot-operated pressure regulating valve 300e, when the primary pressure P1 is higher than the valve opening pressure Ppo of the pilot section 200e and lower than the valve opening pressure Pmo (=relief pressure Pre) of the main valve section 100e, the main valve section 100e is in a valve-closed state, while the pilot section 200e is in a valve-opened state. At this time, the pilot valve element 240 of the pilot section 200e moves in the valve-opening direction (see arrow M1' in FIG. 10(d)).

[0125] Furthermore, similar to state 1, by simultaneously employing pressure fluctuation damping means (1) (circumferentially extending gap Gc) and pressure fluctuation damping means (2) (circumferentially extending gap at the most upstream of the intermediate pressure flow path), pressure fluctuations can be reliably damped when the pressure wave passes through the circumferentially extending gap Gc and when it passes through the entire length of the intermediate pressure flow path from the back pressure chamber 105c, via the third fluid path 3', to the bellows accommodating chamber 216.

[0126] (Condition 3: When the primary pressure is higher than the main valve opening pressure) 10(e) and 10(f), in the pilot-operated pressure regulating valve 300e, when the primary pressure P1 is higher than the valve opening pressure Pmo (=relief pressure Pre) of the main valve section 100e, the main valve section 100e and the pilot section 200e are each in a valve open state. At this time, first, the pilot valve element 240 of the pilot section 200e moves further in the valve opening direction (see arrow M2' in FIG. 10(f)), which causes the main valve element 140' of the main valve section 100e to move in the valve opening direction (see arrow M3' in FIG. 10(e)), and the locking portion 140c' abuts against the main valve element stopper portion 233', thereby maintaining the main valve element 140' in a valve fully open state.

[0127] <Regarding the pressure fluctuation damping means (1-3) (maintaining the circumferentially extending gap by the biasing means)> As shown in FIG. 10( e), the pressure fluctuation damping means (1-3) (maintaining the circumferential gap by a biasing means) in this embodiment is an O-ring 192 (biasing means) that is provided between the main valve element 140′ and the outer peripheral surface (slide guide surface) of the pilot valve seat 231′ and biases the axis of the main valve element 140′ along the axis Lm. The outer peripheral surface of the pilot valve seat 231′ is formed concentrically with the axis Lm. The elastic force of the O-ring 192 suppresses oscillations occurring in the main valve element 140′, making the circumferential gap Gc a circumferentially continuous and steadily uniform gap. Furthermore, the sliding resistance of the O-ring 192 suppresses chattering occurring in the main valve element 140′, thereby maintaining a desired valve opening flow rate in the main valve portion 100e.

[0128] As described above, in the fifth embodiment, similarly to the fourth embodiment, by simultaneously employing a pressure fluctuation buffering means (1) (circumferentially extending gap) and a pressure fluctuation buffering means (2) (circumferentially extending gap at the most upstream of the intermediate pressure flow path), it is possible to solve the conventional problem (reduced durability of the pressure-sensing part due to pressure fluctuations in the primary side pressure) and improve reliability.

[0129] In the fifth embodiment, similarly to the fourth embodiment, pressure fluctuations can be more efficiently damped by employing pressure fluctuation damping means (1-1) (concave and recessed portions on the surface defining the circumferentially extending gap) or pressure fluctuation damping means (1-2) (plurality of circumferential grooves on the surface defining the circumferentially extending gap). Furthermore, by employing pressure fluctuation damping means (1-3) (maintaining the circumferentially extending gap by a biasing means), chattering can be suppressed and a desired valve opening flow rate can be maintained in the main valve portion 100e. In addition, by employing pressure fluctuation damping means (2') (bent portion of the intermediate pressure flow path), pressure fluctuations can be more efficiently damped in the back pressure chamber 105c.

[0130] Furthermore, in the fifth embodiment, by employing a manifold 120 in which the first fluid path 1' and the second fluid path 2' are formed, the strength of the connection with the pilot operated pressure regulating valve 300e can be improved. Also, in the fifth embodiment, by employing a nested structure for the pilot valve seat member 230' and the main valve element 140', the overall length in the directions of the axes Lm and Lp can be reduced, thereby reducing the moment generated when the pilot operated pressure regulating valve 300e tries to tip over. As a result, in the fifth embodiment, damage to the connection between the manifold 120 in which the first fluid path 1' and the second fluid path 2' are formed and the valve body 110e can be suppressed.

[0131] <Other> In the first to fifth embodiments, in addition to the pressure fluctuation buffering means (1) (circumferentially extending gap) and the pressure fluctuation buffering means (2) (circumferentially extending gap at the most upstream of the intermediate pressure flow path), all of the pressure fluctuation buffering means (1-1) (uneven portion on the surface defining the circumferentially extending gap) or the pressure fluctuation buffering means (1-2) (plurality of circumferential grooves on the surface defining the circumferentially extending gap), the pressure fluctuation buffering means (1-3) (the circumferentially extending gap is maintained by a biasing means), and the pressure fluctuation buffering means (2') (bent portion of the intermediate pressure flow path) are adopted, but are not limited to this. For example, as long as at least the pressure fluctuation buffering means (1) (circumferentially extending gap) and the pressure fluctuation buffering means (2) (circumferentially extending gap at the most upstream of the intermediate pressure flow path) are simultaneously employed, the pressure fluctuation buffering means may not employ any of the pressure fluctuation buffering means (1-1) (uneven portion on the surface defining the circumferentially extending gap) or the pressure fluctuation buffering means (1-2) (multiple circumferential grooves on the surface defining the circumferentially extending gap), the pressure fluctuation buffering means (1-3) (the circumferentially extending gap is maintained by a biasing means), and the pressure fluctuation buffering means (2') (bent portion of the intermediate pressure flow path), or may employ a combination including at least one of them.

[0132] In the first to fifth embodiments, the pilot valve portion 241 provided on one end side of the pilot valve body 240 has a truncated cone shape, but is not limited to this and may have, for example, a flat shape that covers the pilot valve seat 231c when viewed from the direction of the axis Lp.

[0133] It goes without saying that the pilot-operated pressure regulating valves 300a, 300b, 300c, 300d, and 300e of the present embodiment are applicable not only to the refrigerant circuits illustrated, but also to any fluid devices and fluid circuits. Furthermore, the present invention is not limited to the above-described aspects, embodiments, and modified examples, and can be appropriately changed or modified within the scope of the technical concept of the present invention. [Explanation of symbols]

[0134] 1 First joint pipe 1' First fluid path 2 Second joint pipe 2' Second fluid path 3. Third joint pipe (fluid path) 3' Third fluid path (fluid path) 4 Fourth joint pipe (fluid path) 4' Fourth fluid path (fluid path) 100a,100b,100c,100d,100e Main valve part 105 Main valve body 105a Main valve seat 105b Main valve guide hole 105c Back pressure chamber 110c, 100d, 100e valve body 111 Main valve inlet port (inlet port) 112 Main valve port 113 Pressure equalizing port 114 Communication path 120 manifold 125 Main valve chamber 140,140' Main valve body 140a, 140a' Main valve seat 140b, 140b' Piston section 140c,140c' Locking part 140d' Main valve body through hole 140e' sliding hole 141' retaining member 160 Main valve spring unit 162 Adjustment screw cover 162a Male thread 162b Main valve body stopper part 163 Main valve spring 191 Leaf spring (biasing means) 192 O-ring (biasing means) 200a, 200b, 200c, 200d, 200e Pilot Section 205 Pilot body 206 Valve opening spring 207 Other side spring support 208 One side spring support 210 Pilot valve housing 211 Pilot inlet port 212,212' Pilot Outlet Port 213 Intermediate Room 215 Pilot valve chest 216 Bellows Containment Room (Pressure-Sensing Unit Containment Room) 218 One side spring support 220 Spring Case 221 Spring Containment Room 222 Female thread 230,230' Pilot valve seat member 231,231' Pilot valve seat 231a Pilot valve port 231b Internal passage 231c Pilot valve seat 232,232' Pilot guide section 232a Radial communication hole 233' Main valve body stopper part 240 Pilot valve body 241 Pilot valve section 242 Pilot guide shaft 242a Annular groove 250 pressure-sensitive units 251 Pressure-sensing bellows (pressure-sensing part) 253 Bellows top cover 253a Insertion hole 253b Bellows top cover joint 253c Contact part 255 Connecting rod 255a Large diameter section 255b Small diameter section 255c Step 255d flange 260 Adjustment spring unit 261 Spring support member 261a Boss section 261b Tsubabe 262 Adjustment screw member 262a Annular wall 262b Top part 262c male thread 263 Adjustment spring 270 Lower connection means 280 Upper connection means 300a, 300b, 300c, 300d, 300e Pilot-operated pressure regulating valve Dm1 Outer diameter of piston Dm2 Main valve port diameter Dp2 Pilot valve port diameter Dp1 Average inner diameter of pressure-sensitive bellows Dp2 Pilot valve port diameter Fm biasing force of main valve spring 163 Fp1 Valve opening spring force Fp2: Force exerted by the pressure-sensitive bellows itself Fp3 Adjustment spring force Lm Axis of the main valve Lp Pilot axis M1,M1',M2,M2',M3,M3' Valve opening direction P1 Primary pressure P1' intermediate pressure P2 Outlet pressure Pmo Main valve opening pressure Ppo Pilot valve opening pressure Pre-relief pressure Q is the flow rate of the working fluid Sm1 Pressure-receiving area of ​​piston Sm2 Main valve seat pressure area Sp1 Effective pressure receiving area of ​​pressure sensing bellows Sp2 Pilot valve pressure area

Claims

1. a main valve portion including: a main valve chamber; an inlet port communicating with the main valve chamber; a main valve port communicating with the main valve chamber via a main valve seat; a main valve element capable of abutting against or separating from the main valve seat; a main valve guide hole for axially guiding the main valve element; a back pressure chamber provided on the opposite side of the main valve chamber with the main valve element in between; pressure fluctuation damping means for constantly communicating the main valve chamber with the back pressure chamber and for damping pressure fluctuations from the main valve chamber to the back pressure chamber; and a pressure equalizing port communicating with the back pressure chamber; a pilot section including a pressure-sensitive section, a pressure-sensitive section chamber that accommodates the pressure-sensitive section, a pilot inlet port that communicates with the pressure-sensitive section chamber, a pilot valve port that communicates with the pressure-sensitive section chamber via a pilot valve seat, and a pilot valve body that is connected to the pressure-sensitive section and can abut against or move away from the pilot valve seat depending on the displacement of the pressure-sensitive section; a fluid path communicating between the pressure equalization port and the pilot inlet port, and between the main valve port and the pilot valve port; Equipped with the pressure fluctuation buffering means forms a circumferentially extending gap between the main valve body and the main valve guide hole, and constantly connects the main valve chamber and the back pressure chamber to the pressure sensing portion accommodating chamber only via the circumferentially extending gap; A pilot-operated pressure regulating valve in which the pressure-sensing section responds to the pressure of the inlet port via the back pressure chamber, so that when the pressure of the inlet port is lower than the valve-opening pressure of the pilot section, the pressure in the back pressure chamber and the pressure in the main valve chamber are equal, when the pressure is higher than the valve-opening pressure of the pilot section and lower than the valve-opening pressure of the main valve section, a pressure difference is generated between the back pressure chamber and the main valve chamber, and when the pressure of the inlet port is higher than the valve-opening pressure of the main valve section, the pressure difference between the back pressure chamber and the main valve chamber opens the main valve element.

2. 2. The pilot-operated pressure regulating valve according to claim 1, wherein the pressure fluctuation damping means is an uneven portion provided on the main valve body and / or the main valve guide hole.

3. 3. The pilot-operated pressure regulating valve according to claim 2, wherein the pressure fluctuation damping means is a plurality of circumferential grooves provided in the main valve body and / or the main valve guide hole along the axial direction.

4. 2. The pilot-operated pressure regulating valve according to claim 1, wherein the pressure fluctuation damping means is a biasing means that is provided between the main valve body and a slide guide surface that is formed concentrically with the axis at a position separated from the circumferentially extending gap, and that biases the axis of the main valve body along the axial direction.

5. 2. The pilot-operated pressure regulating valve according to claim 1, wherein the pressure fluctuation damping means is a bent portion formed in a flow path extending from the back pressure chamber to the pressure sensing portion accommodating chamber.

Images