Pilot-operated pressure regulating 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-sensitive element. [Background technology]

[0002] Pressure regulating valves have a pressure-sensitive element, and depending on the drive method, they can be broadly classified into two types: a direct-acting type in which the main valve body is directly driven by the displacement of the pressure-sensitive element connected to the main valve body, and a pilot-operated type in which the pressure in the back pressure chamber is adjusted by the displacement of the pressure-sensitive element connected to the pilot valve body, and the main valve body is driven by the pressure difference between this back pressure chamber and the primary side pressure.

[0003] Pressure regulating valves with a pressure-sensitive element do not require complex control circuits, and therefore, compared to pressure regulating valves with solenoids, they are lower cost and more reliable, and there is a demand for their expanded applications in high-flow fluid circuits. In high-flow fluid circuits, the diameter of the main valve port of the main valve body is necessarily larger, requiring a larger driving force to the main valve body. For this reason, while there are limitations to the driving force of the pressure-sensitive element in direct-acting valves, pilot-operated valves allow for relatively easy adjustment of the driving force to the main valve body, that is, the magnitude of the pressure difference between the back pressure chamber and the primary side pressure, and are therefore widely used in high-flow fluid circuits.

[0004] As an example, as shown in Figure 11, Patent Document 1 describes a pilot-operated pressure regulating valve 1100 (hereinafter referred to as "conventional pilot-operated pressure regulating valve") having a reversing plate 1251, which has, in order along the 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-sensitive part housing chamber 1216, and further has 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 body 1140 that can contact or separate from the main valve seat 1105a due to the differential pressure between the main valve chamber 1125 and the back pressure chamber 1105c. In addition, in Patent Document 1, the primary side pressure P1 and the secondary side pressure P2 are introduced to the main valve inlet port 1111 and the main valve port 1112 via the first joint pipe 1101 and the second joint pipe 1102, respectively.

[0005] Furthermore, Patent Document 1 describes a device having a reversing plate 1251 housed in a pressure-sensitive section housing chamber 1216, a pilot communication passage 1226 communicating with a back pressure chamber 1105c via a pilot valve seat 1231c, and an internal communication passage 1237 connecting the main valve inlet port 1111 and the pressure-sensitive section housing chamber 1216. In addition, Patent Document 1 describes a device comprising a pilot valve body 1240 connected to the reversing plate 1251 and capable of contacting or separating from the pilot valve seat 1231c in accordance with the snap-action reversing operation of the reversing plate 1251.

[0006] As a result, in the conventional pilot-operated pressure regulating valve 1100, the main valve body 1140 is subjected to the fluid pressure of the main valve chamber 1125 and the main valve port 1112 in the valve opening direction, and the fluid pressure of the back pressure chamber 1105c in the valve closing direction. This main valve body 1140 controls the opening and closing of the main valve port 1112 (see white arrow M1102 in Figure 11). Furthermore, the fluid pressure of this back pressure chamber 1105c responds to the displacement of the reversing plate 1251, which is sensitive to the fluid pressure of the main valve inlet port 1111, and the pilot valve body 1240 controls the opening and closing of the pilot communication passage 1226 (see white arrow M1101 in Figure 11).

[0007] In the conventional pilot-operated pressure regulating valve 1100, the pressure-sensitive chamber 1216 housing the reversing plate 1251 is constantly in communication with the main valve inlet port 1111 via an internal communication passage 1237. As a result, the reversing plate 1251 is repeatedly subjected to unsteady pressure fluctuations of the primary pressure P1, specifically shock pressures caused by sudden pressure increases, which could lead to a decrease in the durability of the reversing plate 1251 (hereinafter referred to as "conventional problem (decreased durability of the pressure-sensitive part due to primary pressure fluctuations)").

[0008] Furthermore, in order to resolve the conventional problem (reduced durability of the pressure-sensitive part due to pressure fluctuations on the primary side), it is conceivable to reduce the diameter of the internal communication passage 1237 to suppress pressure fluctuations to the reversing plate 1251. However, this cannot be adopted because it is difficult to process the micro-holes and new challenges such as high costs arise. [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] Japanese Patent Publication No. 2002-349732 [Overview of the project] [Problems that the invention aims to solve]

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

[0011] To solve the above problems, the pilot-operated pressure regulating valve has a main valve section comprising: 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 body that can abut against or separate from the main valve seat; a main valve guide hole that guides the main valve body in the axial direction; a back pressure chamber provided on the opposite side of the main valve chamber, sandwiching the main valve body; a pressure fluctuation buffering means that keeps the main valve chamber and the back pressure chamber in constant communication and buffers pressure fluctuations from the main valve chamber to the back pressure chamber; and a pressure equalization port communicating with the back pressure chamber. Department The pressure fluctuation buffering means comprises a pilot section having a pressure-sensitive element, a pressure-sensitive element housing chamber housing the pressure-sensitive element, a pilot inlet port communicating with the pressure-sensitive element housing chamber, a pilot valve port communicating with the pressure-sensitive element housing chamber via a pilot valve seat, and a pilot valve body connected to the pressure-sensitive element and capable of contacting or separating from the pilot valve seat in accordance with the displacement of the pressure-sensitive element, and a fluid path communicating between the equalizing port and the pilot inlet port, and between the main valve port and the pilot valve port, respectively, wherein the pressure fluctuation buffering means forms a circumferentially extending gap between the main valve body and the main valve guide hole, and the circumferential The main valve chamber and the back pressure chamber are constantly in communication with the pressure-sensitive part housing chamber only through an extended gap. The pressure-sensitive part senses the pressure at the inlet port via the back pressure chamber. When the pressure at 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 become the same. When the pressure is higher than the valve opening pressure of the pilot section but lower than the valve opening pressure of the main valve section, a pressure difference is created between the back pressure chamber and the main valve chamber. When the pressure at 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 causes the main valve body to open.

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

[0013] Further, in the pilot-type pressure regulating valve, the pressure fluctuation buffering means may be a plurality of circumferential grooves provided axially along the main valve body or / and the main valve guide hole.

[0014] Further, in the pilot-type pressure regulating valve, the pressure fluctuation buffering means may be urging means provided between a slide guide surface formed concentrically with the axis at a position separated from the circumferentially extending gap and the main valve body, and urging the axis of the main valve body along the axial direction.

[0015] Further, in the pilot-type pressure regulating valve, the pressure fluctuation buffering means may be a bent portion formed in a flow path from the back pressure chamber to the pressure-sensitive portion accommodating chamber.

Advantages of the Invention

[0016] According to the present invention, it is possible to provide a pilot-type pressure regulating valve that can suppress rapid pressure fluctuations in the pressure-sensitive portion and improve reliability without requiring complicated processing.

Brief Description of the Drawings

[0017] [Figure 1] It is a cross-sectional view showing a pilot-type pressure regulating valve according to a first embodiment of the present invention. [Figure 2] It is an explanatory view of an external force acting on the main valve portion surrounded by the broken line II shown in FIG. 1. [Figure 3] It is an explanatory view of an external force acting on the pilot portion surrounded by the broken line III shown in FIG. 1. [Figure 4] It is a partially enlarged view of the pilot-type pressure regulating valve of FIG. 1, where (a), (c), (e) are regions surrounded by the broken lines IVa, c, e shown in FIG. 1, (b), (d), (f) are regions surrounded by the broken lines IVb, d, f shown in FIG. 1, (a), (b) represent state 1 (the main valve portion and the pilot portion are in the valve-closed state), (c), (d) represent state 2 (the main valve portion is in the valve-closed state and the pilot portion is in the valve-open state), and (e), (f) represent state 3 (the main valve portion and the pilot portion are in the valve-open state). [Figure 5] It is a diagram showing the fluid characteristics with respect to the change in the primary-side pressure in the pilot-type pressure regulating valve of FIG. 1. (a) represents the primary-side pressure-intermediate pressure characteristics, and (b) represents the primary-side pressure-flow rate characteristics, respectively. [Figure 6] It is a cross-sectional view showing the pilot-type pressure regulating valve according to the second embodiment. [Figure 7] It is a cross-sectional view showing the pilot-type pressure regulating valve according to the third embodiment. [Figure 8] It is a cross-sectional view showing the pilot-type pressure regulating valve according to the fourth embodiment. (a) represents the front cross-sectional view, and (b) represents the cross-sectional view VIIIb-VIIIb shown in (a), respectively. [Figure 9] It is a cross-sectional view showing the pilot-type pressure regulating valve according to the fifth embodiment. [Figure 10] It is a partially enlarged view of the pilot-type pressure regulating valve of FIG. 9. (a), (c), and (e) represent the regions surrounded by the broken lines Xa, c, and e shown in FIG. 9, and (b), (d), and (f) represent the regions surrounded by the broken lines Xb, d, and f shown in FIG. 9. (a) and (b) represent state 1 (the main valve part and the pilot part are in the valve-closed state), (c) and (d) represent state 2 (the main valve part is in the valve-closed state and the pilot part is in the valve-open state), and (e) and (f) represent state 3 (the main valve part and the pilot part are in the valve-open state), respectively. [Figure 11] It represents a cross-sectional view of a pilot-type pressure regulating valve according to the prior art.

Embodiments for Carrying Out the Invention

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

[0019] <Regarding Terms> In this specification, “up,” “down,” “left,” and “right” refer to the directions shown in Figures 1 to 4, Figures 6 to 7, Figure 8(a), and Figures 9 to 10. In this specification and the claims, “one end” and “the other end” refer to the “lower end” and “upper end” in the axial direction extending in the vertical direction of the drawings. In this specification and the claims, “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 minimum inner diameter of the bellows shape (the inner diameter of the “valley” portion of the bellows shape projecting toward the central axis side of the pressure-sensitive bellows) and the maximum inner diameter (the inner diameter of the “peak” portion of the bellows shape projecting away from the central axis side of the pressure-sensitive bellows). In this specification and the claims, “guideable” includes “slidable.” In this specification and the claims, “concave-concave engagement” refers to a configuration in which a recessed shape and a protruding shape in the axial direction engage with each other. In this specification, “intermediate chamber” means “space other than the pressure-sensitive element housing chamber and the pilot valve chamber.” In this specification, “circumferentially extending gap” means “a gap provided between radially opposing surfaces that extends circumferentially.” In this specification, “recesses” means “not only recesses, but also C-shaped grooves, spiral grooves, axially extending grooves, grooves inclined with respect to the axial direction, multiple recesses, multiple protrusions, or an annular groove formed on one of the surfaces defining the circumferentially extending gap, in which a C-shaped ring housed in this annular groove protrudes toward the other, or an annular groove formed on one of the surfaces defining the circumferentially extending gap, in which an O-ring housed in this annular groove protrudes toward the other, and the other surface is provided with a groove that extends or is inclined toward the axial direction.” In this specification, "bent section" means "at least one section in which the flow path bends at least 90° at any point in the intermediate pressure flow path from the back pressure chamber to the bellows housing chamber."In this specification, the term "fluid path communicating between the main valve port and the pilot valve port" refers to "a relatively short and direct fluid path communicating between 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 communicating between 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) <About the configuration of a pilot-operated pressure regulating valve> A pilot-operated pressure regulating valve 300a according to the first embodiment of the present invention will be described with reference to Figures 1 to 3. The pilot-operated pressure regulating valve 300a consists of a main valve section 100a and a pilot section 200a.

[0021] <Regarding the composition of the main office> As shown in Figures 1 and 2, the main valve section 100a mainly consists of a main valve body 105, a main valve element 140, and a main valve spring unit 160. The components of the main valve section 100a will be described in order below. As will be explained in detail later, in this embodiment, by simultaneously employing pressure fluctuation buffering means (1) (circumferentially extending gap) and pressure fluctuation buffering means (2) (circumferentially extending gap at the uppermost part of the intermediate pressure flow path), the conventional problem (reduction in the durability of the pressure-sensitive part due to pressure fluctuations of the primary side pressure) can be resolved. The pressure fluctuation buffering means (1) (circumferentially extending gap) is to form a circumferentially extending gap Gc (see Figure 4(a)) between the outer circumferential surface of the piston portion 140b and the inner circumferential surface of the main valve guide hole 105b, as shown in Figure 2, and the pressure fluctuation buffering means (2) (circumferentially extending gap at the uppermost part of the intermediate pressure flow path) is to keep the main valve chamber 125 and the back pressure chamber 105c in constant communication only through the circumferentially extending gap Gc, as shown in Figure 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 penetrates along the axis Lm of the main valve section 100a (hereinafter, in the description of the main valve section 100a, it will simply be referred to as "axis Lm"). The 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 with an inner diameter larger than that of the main valve port 112, a main valve guide hole 105b, and a back pressure chamber 105c are provided in communication with each other through this through hole.

[0023] Furthermore, the main valve body 105 has a through hole extending radially from the main valve chamber 125, and a main valve inlet port 111 (inlet port) connected to the first joint pipe 1 is provided in this through hole. In addition, the main valve body 105 has a through hole extending radially from the back pressure chamber 105c, and a pressure equalization port 113 connected to the communication passage 114 of the third joint pipe 3 is provided in this through hole. Moreover, the main valve body 105 has a female threaded portion 105d on the inner circumference side of the other end, which is screwed into a male threaded portion 162a provided on the outer circumference side of the adjustment screw cover 162 so as to be movable in the axial direction Lm. The back pressure chamber 105c is sealed through this screwed portion.

[0024] <Regarding the main valve body> The main valve body 140 comprises a main valve seat 140a provided on one side and having a substantially cylindrical shape, a cylindrical piston portion 140b extending to the other side in the direction of the axis Lm, and a locking portion 140c further extending from the piston portion 140b to the other side in the direction of the axis Lm. The main valve seat 140a is made of a resin material such as PTFE and is arranged to cover the main valve seat 105a when viewed from the direction of the axis Lm. The piston portion 140b and the locking portion 140c are made of a metal material such as brass. Here, the piston portion 140b is arranged so as 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 one end of the adjustment screw cover 162, so that the main valve body 140 is always biased in the valve closing direction (see Fm in Figure 2).

[0025] The movement of the main valve body 140 in the axial direction Lm will be described in detail later, but it is caused by 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 Figure 2). Due to these external forces, the main valve body 140 moves closer to or further away from the main valve seat 105a, and the valve opening is determined. Here, as will be described in detail later, the locking portion 140c comes into contact with the main valve body stopper portion 162b of the adjustment screw cover 162, thereby defining the maximum valve lift amount from the valve closed state to the fully open state, which is the maximum valve lift state.

[0026] Furthermore, leaf springs 191 are attached to the other end of the main valve body 140 at equal intervals in the circumferential direction, surrounding the locking portion 140c. These leaf springs 191 are made of a metal material such as stainless steel or phosphor bronze, and are relatively thin and elastic members formed by press working. As shown in Figure 2, a biasing force is generated when the curved portion comes into contact with the inner circumferential surface of the back pressure chamber 105c, causing it to flex.

[0027] <About the main valve spring unit> The main valve spring unit 160 consists of an adjustment screw cover 162 and a main valve spring 163 sandwiched between one end of the adjustment screw cover 162 and the other end of the piston portion 140b. The adjustment screw cover 162 is made of a metal material such as stainless steel and has a main valve body stopper portion 162b at one end that extends to one side in the direction of the axis Lm. A male threaded portion 162a is provided on the outer circumference of the adjustment screw cover 162 and is screwed into a female threaded portion 105d provided on the inner circumference 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, and the pressure at which the main valve body 140 opens (valve opening pressure Pmo (= relief pressure Pre) of the main valve portion 100a) (see Figure 5) can be adjusted.

[0028] <About the configuration of the pilot unit> As shown in Figures 1 and 3, the pilot section 200a mainly consists of a pilot body 205, a pilot valve seat member 230, a pilot valve body 240, a pressure-sensitive unit 250, an adjustment spring unit 260, a lower connecting means 270, and an upper connecting means 280. The components of the pilot section 200a will be described in order below. In the pilot section 200a, the pilot valve seat member 230, the pilot valve body 240, the lower connecting means 270, the pressure-sensitive unit 250, the upper connecting means 280, and the adjustment spring unit 260 are assembled to the pilot body 205 in an indirectly engaged state from one side to the other. The direction of the fluid path is from the third joint pipe 3 (fluid path) to the fourth joint pipe 4 (fluid path).

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

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

[0031] Furthermore, the pilot valve housing 210 has a through-hole that extends radially from the intermediate chamber 213, and a pilot inlet port 211 is provided in this through-hole, which is connected to the third joint pipe 3. This configuration allows the intermediate pressure P1' (≤ primary pressure P1) to be introduced into the intermediate chamber 213, the pilot valve chamber 215 (described later), and the bellows housing chamber 216 via the pilot inlet port 211 when the valve is closed.

[0032] The spring case 220 is a hollow cylindrical member made of a metal material such as brass, having a through hole that penetrates along the axis Lp, and is provided with a spring housing chamber 221. Furthermore, a female threaded portion 222 is provided on the inner circumference of the other end of the spring case 220, and is screwed into a male threaded portion 262c provided on the outer circumference of the adjustment screw member 262 so as to be movable in the direction of the axis Lp. Air is constantly introduced into the spring housing chamber 221 through this threaded portion.

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

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

[0035] The pilot guide section 232 is provided in the intermediate chamber 213 and has a cylindrical shape that rises from around the other end of the pilot valve seat section 231. It defines the pilot valve chamber 215 on its inner circumference and has four radial communication holes 232a arranged at equal intervals in the circumferential direction to connect the pilot valve chamber 215 and the intermediate chamber 213 in the radial direction centered on the axis Lp. In this embodiment, the radial communication holes 232a are arranged at equal intervals in the circumferential direction, but the number and arrangement of the radial communication holes 232a can be appropriately set according to the intended use of the pilot section 200a.

[0036] <About the pilot valve> The pilot valve body 240 comprises a pilot valve portion 241 provided on one side and having a substantially conical shape, and a pilot guide shaft portion 242 having a cylindrical shape that extends to the other side in the axial direction Lp. The pilot guide shaft portion 242 is positioned on the inner circumference side of the pilot guide portion 232, except for the other end. An annular groove portion 242a is formed on the outer circumferential surface of the other end of the pilot guide shaft portion 242. Here, the other-side spring receiving portion 207 is made of a ring-shaped thin plate having a plurality of protrusions on its inner circumference, and engages with the annular groove portion 242a via these multiple protrusions.

[0037] The pilot guide shaft portion 242 of the pilot valve body 240 is positioned to be guided in the axial direction Lp within the pilot guide portion 232 of the pilot valve seat member 230. Furthermore, the pilot valve body 240 is constantly biased in the valve opening direction by a valve opening spring 206 sandwiched between the other-side spring receiving portion 207, which engages with the annular groove portion 242a of the pilot valve body 240, and the one-side spring receiving portion 218 of the pilot valve housing 210 (see Fp1 in Figure 3).

[0038] The movement of the pilot valve body 240 in the axial direction Lp will be described in detail later, but it is caused by the pressure difference between the intermediate pressure P1' (P1'≦P1) and the secondary pressure P2, the biasing force of the pressure-sensitive bellows (pressure-sensitive part) 251 and the adjustment spring 263 acting on the other end of the pilot valve body 240 (see Fp2 and Fp3 in Figure 3), and the biasing force of the valve opening spring 206 acting on the other spring receiving part 207 (see Fp1 in Figure 3). Due to these external forces, the pilot valve part 241 moves closer to or further away from the pilot valve seat 231c, and the valve opening degree is determined. Here, as will be described in detail later, the stepped portion 255c of the connecting rod 255 comes into contact with the bellows upper cover 253, which defines the maximum valve lift amount from the valve closed state to the fully open state, which is the maximum valve lift state of the pilot valve body 240.

[0039] <About the pressure-sensitive unit> The pressure-sensitive unit 250 consists of a pressure-sensitive bellows 251, which is a pressure-sensitive part; a bellows upper cover 253; and a connecting rod 255 having one end and the other end that extend along the axis Lp. The pressure-sensitive bellows 251 has its one end and the other end that extend along the axis Lp connected to one end of the connecting rod 255 and the bellows upper cover 253, respectively. Here, the elastic force of the pressure-sensitive bellows 251 itself biases the pilot valve body 240 in the valve closing direction (see Fp2 in Figure 3). The pressure-sensitive 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-sensitive bellows 251 is connected to one end of the connecting rod 255 and the bellows upper cover 253, thereby introducing an intermediate pressure P1' (P1' ≤ P1) into the external space of the pressure-sensitive bellows 251 at all times via the intermediate chamber 213 and the bellows housing chamber 216. On the other hand, air is constantly introduced into the internal space of the pressure-sensitive bellows 251 through the gap formed between the small-diameter portion 255b of the connecting rod 255 and the insertion hole 253a of the bellows upper cover 253, and through the gap formed between the upper ball 283 and the contact portion 253c of the bellows upper cover 253. Furthermore, in this pressure-sensitive bellows 251, the dimensional relationship of each part is set such that the outer diameter of the peaks and the inner diameter of the valleys of the bellows shape are always in a non-contact state with the pilot valve housing 210 and the connecting rod 255, respectively. In this embodiment, the pressure-sensitive part is a pressure-sensitive bellows 251, but it is not limited to this, and may be a diaphragm, for example.

[0041] The connecting rod 255 comprises a substantially cylindrical large-diameter portion 255a extending to one side in the axial direction Lp, and a substantially cylindrical small-diameter portion 255b extending from the large-diameter portion 255a to the other side in the axial direction Lp. A flange portion 255d is formed at one end of the large-diameter portion 255a, which protrudes radially and to which one end of the pressure-sensitive bellows 251 is connected by welding. Furthermore, an annular stepped portion 255c is formed between the large-diameter portion 255a and the small-diameter portion 255b.

[0042] The bellows upper cover 253 extends concentrically along the axial direction Lp and includes an insertion hole 253a through which the small-diameter portion 255b of the connecting rod 255 is inserted, a bellows upper cover joint portion 253b to which the other end of the pressure-sensitive bellows 251 is connected, and a cylindrical contact portion 253c that extends concentrically along the axial direction 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, the pressure-sensitive unit 250 is fixed to the pilot body 205 so as not to be displaced relative to it by welding or the like to the other ends of the bellows upper cover 253 and the pilot valve housing 210.

[0043] <About the adjustment spring unit> The adjustment spring unit 260 consists of a spring receiving member 261, an adjustment screw member 262, and an adjustment spring 263 sandwiched between the spring receiving member 261 and the adjustment screw member 262, which biases the pilot valve section 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 housing chamber 221 of the spring case 220. The spring receiving member 261 includes a boss portion 261a extending to the other side in the axial direction Lp, and a flange portion 261b provided on one side in the axial direction Lp, on which one end of the adjustment spring 263 is seated. The adjustment screw member 262 includes an annular wall portion 262a extending to one side in the axial direction Lp, and an upper surface portion 262b provided on the other side, on which the other end of the adjustment spring 263 is seated. The outer circumference of the adjustment screw member 262 is provided with a male threaded portion 262c, which is screwed into a female threaded portion 222 provided on the inner circumference of the spring case 220 so as to be movable in the axial direction Lp. This allows the biasing force of the adjustment spring 263 to be adjusted, thereby adjusting the pressure at which the pilot valve body 240 opens (valve opening pressure Ppo) (see Figure 5). In this embodiment, a multi-wound wave spring is used as the adjustment spring 263, but it is not limited to this, and for example, a coil spring may also be used.

[0044] <Regarding the lower connection means> The lower connecting means 270 consists of a pair of recesses 271 and 272 formed on opposing surfaces in the direction of the axis Lp of the pilot valve body 240 and the pressure-sensitive unit 250, and a lower ball 273 that is sandwiched between the pair of recesses 271 and 272 to form a recessed engagement. The pair of recesses 271 and 272 are formed on the axial center of the other end face of the pilot guide shaft 242 and one end face of the large diameter portion 255a, and consist of a conical lower recess 271 and an upper recess 272. This conical shape has a base formed concentrically with the axis Lp and an apex 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 body 240 is positioned within the pilot guide portion 232 of the pilot valve seat member 230 so as to be guided along the axis Lp, and the center position of the lower recess portion 271 is always positioned near the axis Lp. In addition, the center position of the upper recess portion 272 is independently positioned near the axis Lp because a centripetal force acts on the upper recess portion 272 via the lower recess portion 271 and the lower ball 273.

[0046] <Regarding the upper connection means> The upper connecting means 280 consists of a pair of engaging portions 281 and 282 formed on the connecting rod 255 and the spring receiving member 261 on opposing surfaces in the direction of the axis Lp, and an upper ball 283 that is sandwiched between the pair of engaging portions 281 and 282 to form a concave-concave engagement. The pair of engaging portions 281 and 282 are formed on the other end face of the small diameter portion 255b and on the axial center of one end face of the spring receiving member 261, and consist of a conical lower engaging portion 281 and an upper engaging portion 282. This conical shape has a base formed concentrically with the axis Lp and an apex located on the axis Lp. The upper ball 283 is made of a metal material such as stainless steel.

[0047] Here, 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. In addition, the center positions 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, respectively, via the upper ball 283, whose radial movement 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 (decreased durability of the pressure-sensitive part due to pressure fluctuations on the primary side)> As mentioned above, in the conventional pilot-operated pressure regulating valve 1100 shown in Figure 11, the pressure-sensitive chamber 1216 housing the reversing plate 1251 is constantly in communication with the main valve inlet port 1111 via an internal communication passage 1237, and the reversing plate 1251 is repeatedly subjected to shock pressure due to unsteady pressure fluctuations of the primary side pressure P1. As a result, the conventional pilot-operated pressure regulating valve 1100 has the conventional problem (decreased durability of the pressure-sensitive chamber due to pressure fluctuations of the primary side pressure), which may lead to a decrease in reliability.

[0049] In contrast, the first embodiment simultaneously employs pressure fluctuation buffering means (1) (circumferentially extending gap) and pressure fluctuation buffering means (2) (circumferentially extending gap at the uppermost part of the intermediate pressure flow path), thereby eliminating the conventional problem (decreased durability of the pressure-sensitive part due to pressure fluctuations in the primary side pressure).

[0050] <About the operation of pilot-operated pressure regulating valves> The operation of the pilot-operated pressure regulating valve 300a will be explained using Figures 1 to 5, illustrating the pressure fluctuation buffering means (1) (circumferentially extending gap) and the pressure fluctuation buffering means (2) (circumferentially extending gap at the uppermost part of the intermediate pressure flow path). In this explanation, the relationship between the external forces acting on the main valve section 100a and the pilot section 200a will be shown in the order of state 1, state 2, and state 3 (see Figure 5). Here, the pilot-operated pressure regulating valve 300a will be described as being used in a refrigerant circuit, but it is not limited to this. As shown in Figure 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 equalizing port 113 is connected to the third joint pipe 3 at the intermediate pressure P1'. Furthermore, 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 on the low-pressure (secondary pressure P2) side. This fourth joint pipe 4 is connected to the second joint pipe 2 via a T-shaped joint. In addition, 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, as shown by the dashed line (Flow) in Figure 2, through the main valve inlet port 111, to the back pressure chamber 105c, the equalizing port 113, and the communication passage 114 via the circumferentially extending gap Gc, and then introduced into the bellows housing chamber 216 via the pilot inlet port 211 and the intermediate chamber 213, as shown by the dashed line (Flow) in Figure 3.

[0051] (Condition 1: When the primary side pressure is lower than the valve opening pressure of the pilot unit) As shown in Figure 5(b), in the pilot-operated pressure regulating valve 300a, when the primary 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 both closed (see Figures 4(a) and (b)). As a result, the flow rate Q of the working fluid passing through the pilot-operated pressure regulating valve 300a is 0. Also, as shown in Figure 1, the flow in the back pressure chamber 105c, the communication passage 114, and the bellows housing chamber 216 is generally stagnant, so the pressure P1' (hereinafter referred to as "intermediate pressure") in this space is equalized to the primary pressure P1 in the main valve chamber 125 via the circumferentially extending gap Gc (P1'=P1) (see Figure 5(a)).

[0052] <Regarding pressure fluctuation buffering means (1) (circumferentially extending gap)> In this embodiment, the pressure fluctuation buffering means (1) (circumferentially extending gap Gc) is a circumferentially extending gap (hereinafter referred to as the "circumferentially extending gap") Gc formed between the outer circumferential surface of the piston portion 140b and the inner circumferential surface of the main valve guide hole 105b, as shown in Figure 4(a). Here, when comparing the circumferentially extending gap Gc of this embodiment with the internal communication passage 1237 of a conventional pilot-operated pressure regulating valve 1100, assuming they have the same flow path area, the circumferentially extending gap Gc of this embodiment has an extremely narrow distance between opposing surfaces in the direction perpendicular to the flow compared to the internal communication passage 1237 of a conventional pilot-operated pressure regulating valve 1100. As a result, when the pressure wave caused by pressure fluctuations of the primary side pressure P1 passes through the circumferentially extending gap Gc, it repeatedly collides with the pair of opposing surfaces of the circumferentially extending gap Gc, thus efficiently buffering the pressure fluctuations. Note that in state 1, there is almost no flow of the working fluid itself through the circumferentially extending gap Gc, and mainly pressure waves are transmitted. Therefore, although there may be discontinuous gaps in the circumferential direction between the outer surface of the piston portion 140b and the inner surface of the main valve guide hole 105b due to uneven contact, the circumferentially extending gap Gc can still 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, it is from 0.001 to 7.0 (mm , 2 ), and preferably, it is 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") from the back pressure chamber 105c, the communication passage 114, and to the bellows housing chamber 216, where the intermediate pressure P1' is obtained. 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 passage 114, the pressure fluctuation can be further buffered. <S

[0055] <0000Z42>(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 valve, 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 valve, 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 temporarily, 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 due to 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 organization 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 240 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), it experiences 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 (P1’ < P1) as the intermediate pressure P1’ increases with the increase in the primary-side pressure 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 path 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] Furthermore, since P1'=P1 (see Figure 5(a)) until the pilot unit 200a starts opening the valve, the valve opening pressure Ppo of the pilot unit 200a is given by (Fp2+Fp3-Fp1) / Sp1. Therefore, the valve opening pressure Ppo of the pilot unit 200a can be adjusted by moving the adjustment screw member 262 in the direction of the axis Lp and appropriately setting the biasing force Fp3 of the adjustment spring 263.

[0072] (Condition 3: When the primary side pressure is higher than the valve opening pressure of the main valve) As shown in Figure 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 each open (see Figures 4(e) and (f)). At this time, first, the pilot valve body 240 of the pilot section 200a moves further in the valve opening direction (see arrow M2 in Figure 4(f)), which causes the main valve body 140 of the main valve section 100a to move in the valve opening direction (see arrow M3 in Figure 4(e)), and the locking portion 140c comes into contact with the main valve body stopper portion 162b, thereby maintaining the fully open state of the main valve body 140. As a result, the working fluid passing through the pilot-operated pressure regulating valve 300a transitions from flowing through the pilot section 200a to flowing through the main valve section 100a. Therefore, the flow rate Q of the pilot-operated pressure regulating valve 300a shows a rapid increasing trend with increasing primary pressure P1, as shown in Figure 5(b). In state 3, as in state 2, the working fluid flows through the circumferentially extending gap Gc, so the main valve body 140 moves to the center position of the axis Lm, and a continuous circumferential gap is formed and maintained between it and the main valve guide hole 105b. Furthermore, in state 3, since the working fluid mainly flows through the main valve port 112 of the main valve section 100a, the influence of pressure fluctuations in the primary pressure P1 on the pressure-sensitive bellows 251 is extremely small compared to state 2, where the working fluid flows only through the pilot valve port 231a of the pilot section 200a.

[0073] (Regarding the relationship between external forces acting on the main valve in state 3) Here, we will explain the relational expression for the external forces acting on the main valve 100a in state 3. The difference between state 3 and state 2 in the main valve 100a is that the valve has changed from a closed state to an open state. Therefore, the relational expression for the external forces acting on the main valve 100a in state 3 is the same as the inequality in (Equation 6) mentioned above, but with the direction reversed. (P1-P1')×Sm1+(P2-P1)×Sm2>Fm (Formula 9)

[0074] Therefore, by moving the adjustment screw cover 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 section 100a can be adjusted.

[0075] (Regarding the relationship between external forces acting on the pilot unit in state 3) Here, we will explain the relational expression for the external forces acting on the pilot unit 200a in state 2. In the pilot unit 200a, the only difference between state 3 and state 2 is the valve opening degree. Therefore, the relational expression for the external forces acting on the pilot unit 200a in state 3 is given by (Equation 8) above, similar to state 2.

[0076] As described above, in 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 uppermost part of the intermediate pressure flow path), pressure fluctuations can be reliably buffered 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 through the connecting passage 114 to the bellows housing chamber 216. This suppresses repeated loading of shock pressure due to sudden pressure increases on the pressure-sensitive bellows 251 and eliminates the conventional problem (decreased durability of the pressure-sensitive part due to pressure fluctuations on the primary side).

[0077] Furthermore, through diligent research, the inventors attempted to further buffer pressure fluctuations in the bellows housing chamber 216 by further examining the configurations of pressure fluctuation buffering means (1) (circumferentially extending gap) and pressure fluctuation buffering means (2) (circumferentially extending gap at the uppermost part of the intermediate pressure flow path).

[0078] <Regarding the consideration of pressure fluctuation buffering means (1) (circumferentially extending gap)> Here, in the pressure fluctuation buffering means (1) (circumferentially extending gap), the pressure fluctuation buffering means (1-1) (uneven surface defining the circumferentially extending gap), the pressure fluctuation buffering means (1-2) (multiple circumferential grooves on the surface defining the circumferentially extending gap), and the pressure fluctuation buffering means (1-3) (maintaining the circumferentially extending gap with a biasing means) are shown as means that cause the pressure wave to collide with various obstacles as it passes through the circumferentially extending gap Gc, thereby further buffering the pressure fluctuation.

[0079] <Regarding pressure fluctuation buffering means (1-1) (uneven portion on the surface defining the circumferentially extending gap)> The pressure fluctuation buffering means (1-1) (uneven portion on the surface defining the circumferentially extending gap) is, as shown in Figure 2, an uneven portion provided on the surface defining the circumferentially extending gap Gc, that is, the outer circumferential surface of the piston portion 140b of the main valve body 140, and / or the inner circumferential surface of the main valve guide hole 105b. Specifically, when the pressure wave caused by pressure fluctuations of the primary pressure P1 passes through the circumferentially extending gap Gc, it collides with this uneven portion, resulting in more collisions compared to a simple curved surface, thus buffering the pressure fluctuations more efficiently. In this embodiment, the uneven portion includes not only an uneven portion provided on the surface defining the circumferentially extending gap Gc, but also C-shaped grooves, helical grooves, grooves extending in the axial direction Lm, grooves inclined with respect to the axial direction Lm, multiple recesses, and multiple protrusions. Furthermore, the uneven portion of this embodiment includes a configuration in which an annular groove is formed on one of the surfaces defining the circumferentially extending gap Gc, and a C-shaped ring housed in this annular groove protrudes toward the other surface. In addition, the uneven portion of this embodiment includes a configuration in which an annular groove is formed on one of the surfaces defining the circumferentially extending gap Gc, and an O-ring housed in this annular groove protrudes toward the other surface, and the other surface is provided with a groove (functioning as a bleed) that extends or is inclined in the axial direction Lm.

[0080] <Regarding pressure fluctuation buffering means (1-2) (multiple circumferential grooves on a surface defining a circumferentially extending gap)> The pressure fluctuation buffering means (1-2) (multiple circumferential grooves on the surface defining the circumferential gap) is, as shown in Figure 2, a plurality of circumferential grooves provided on the surface defining the circumferential gap Gc, that is, the outer circumferential surface of the piston portion 140b of the main valve body 140, and / or the inner circumferential surface of the main valve guide hole 105b. Specifically, when the pressure wave caused by pressure fluctuations of the primary side pressure P1 passes through the circumferential gap Gc, it collides with these multiple circumferential grooves, resulting in more repeated collisions compared to a simple curved surface, thus buffering the pressure fluctuations more efficiently. Furthermore, providing multiple circumferential grooves on the surface defining the circumferential gap Gc offers higher machinability and lower costs compared to providing uneven surfaces.

[0081] <Regarding pressure fluctuation buffering means (1-3) (maintaining the circumferentially extending gap with a biasing means)> In states 2 and 3, as described above, since there is a flow of working fluid through the circumferentially extending gap Gc, the main valve body 140 moves to the center position of the axis Lm, and a continuous circumferential gap is formed and maintained between it and the main valve guide hole 105b. Turbulence is generated in the working fluid passing through this continuous circumferential gap, and this turbulence causes the main valve body 140 to oscillate slightly relative to the main valve guide hole 105b when viewed from the direction of the axis Lm. Therefore, although the circumferentially extending gap Gc is continuous in the circumferential direction, there was a risk that it would become an unsteady gap.

[0082] Therefore, the inventor employs a pressure fluctuation buffering means (1-3) (maintaining the circumferentially extending gap by a biasing means) to ensure that the circumferentially extending gap Gc is continuous and uniform in the circumferential direction in states 2 and 3. This pressure fluctuation buffering means (1-3) (maintaining the circumferentially extending gap by a biasing means) is a leaf spring 191 (biasing means) provided between the main valve body 140 and the inner circumferential surface (slide guide surface) of the back pressure chamber 105c, as shown in Figure 2, which biases the axis of the main valve body 140 to be along the axis Lm direction. The inner circumferential 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 the oscillation that occurs in the main valve body 140. As a result, the circumferential gap Gc can be made continuous and uniform in the circumferential direction. Furthermore, as shown in Figure 5(b), 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 body 140 moves in small increments in the axial direction Lm, which could cause chattering due to repeated collisions with the main valve seat 105a. In contrast, by providing the leaf springs 191 on the main valve body 140, stable sliding resistance can be provided to the movement of the main valve body 140 in the axial direction Lm, thereby suppressing chattering and maintaining the desired valve opening flow rate at the main valve section 100a with a stable valve opening position of the main valve body 140. In this embodiment, the biasing means is a leaf spring 191, but it is not limited to this; for example, a C-shaped ring, a ring spring, or the like may also be used.

[0083] <Regarding the consideration of pressure fluctuation buffering means (2) (circumferentially extending gap at the uppermost upstream of the intermediate pressure flow path)> Here, pressure fluctuation buffering means (2') (bent section of the intermediate pressure passage) is shown, which further buffers pressure fluctuations in pressure fluctuation buffering means (2) (circumferentially extending gap at the uppermost part of the intermediate pressure passage) by having the pressure wave pass through the entire length of the intermediate pressure passage from the back pressure chamber 105c through the connecting passage 114 to the bellows housing chamber 216.

[0084] <Regarding the pressure fluctuation buffering means (2') (bent section of the intermediate pressure flow path)> The pressure fluctuation buffering means (2') (bent section of the intermediate pressure flow path) is a bent section Bp provided in the intermediate pressure flow path from the back pressure chamber 105c to the communication passage 114, as shown in Figures 1 and 2. Specifically, when the pressure wave propagating from the back pressure chamber 105c to the communication passage 114 propagates from the back pressure chamber 105c to the communication passage 114, it first collides with the adjustment screw cover 162 at the bent section Bp where the flow path bends at 90°, then repeatedly collides within the back pressure chamber 105c, and finally propagates to the communication passage 114 in a buffered state. As a result, the pressure wave can more efficiently buffer pressure fluctuations in the back pressure chamber 105c at the bent section Bp.

[0085] In this embodiment, the bent section Bp is provided between the back pressure chamber 105c and the communication passage 114, but it is not limited to this, and at least one may be provided at any position in the intermediate pressure flow path from the back pressure chamber 105c through the communication passage 114 to the bellows housing chamber 216. Also, in this embodiment, the bent section Bp is a 90° bend in the flow path, but it is not limited to this, and any flow path that bends at least 90° or more may be provided, such as a 180° bend in the flow path.

[0086] As described above, in 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 uppermost part of the intermediate pressure flow path), the conventional problem (reduction in the durability of the pressure-sensitive part due to pressure fluctuations of the primary side pressure) can be resolved and reliability can be improved.

[0087] Furthermore, in the first embodiment, by modifying the pressure fluctuation buffering means (1) (circumferentially extending gap), pressure fluctuations can be buffered more efficiently by employing pressure fluctuation buffering means (1-1) (uneven surface defining the circumferentially extending gap) or pressure fluctuation buffering means (1-2) (multiple circumferential grooves on the surface defining the circumferentially extending gap). In addition, by employing pressure fluctuation buffering means (1-3) (maintaining the circumferentially extending gap with a biasing means), the circumferentially extending gap Gc can be made continuous and uniform in the circumferential direction, chattering can be suppressed, and the desired valve opening flow rate in the main valve section 100a can be maintained.

[0088] Furthermore, in the first embodiment, by employing a pressure fluctuation buffering means (2') (a bent portion of the intermediate pressure flow path) as an improved version of the pressure fluctuation buffering means (2) (a circumferentially extending gap at the uppermost part of the intermediate pressure flow path), pressure fluctuations can be buffered 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 with reference to 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 configurations are the same as those of the first embodiment. Here, the same reference numerals are used for the same components, and redundant explanations are omitted.

[0090] As shown in Figure 1, in the pilot-operated pressure regulating valve 300a of the first embodiment, a third joint pipe 3 connecting the main valve section 100a and the pilot section 200a, a fourth joint pipe 4 connecting the pilot section 200a and the second joint pipe 2, an L-shaped joint, a T-shaped joint, etc. are required, which increases the number of parts and raises inventory management costs. Furthermore, because the third joint pipe 3 and the fourth joint pipe 4 need to be routed, there were concerns that a relatively large installation space would need to be secured.

[0091] In contrast, the pilot-operated 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-operated pressure regulating valve 300b of the second embodiment can reduce the number of parts, lower costs, save space, and improve portability compared to the pilot-operated pressure regulating valve 300a of the first embodiment.

[0092] As described above, in the second embodiment, similar 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 uppermost part of the intermediate pressure flow path), the conventional problem (reduction in the durability of the pressure-sensitive part due to pressure fluctuations of the primary side pressure) can be resolved and reliability can be improved.

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

[0094] Furthermore, in the second embodiment, by employing 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 and 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 with reference to Figure 7. In the third embodiment, a common valve body 110c is used for the main valve section 100c and the pilot section 200c, and they are configured integrally. The main valve section 100c's axis Lm is positioned perpendicular to the pilot section 200c's axis Lp. However, the other basic configurations are the same as those of the second embodiment. Here, the same reference numerals are used for the same components, and redundant explanations are omitted.

[0096] As shown in Figure 6, in the pilot-operated pressure regulating valve 300b of the second embodiment, the number of parts can be reduced, resulting in lower costs and space savings. 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 compared to the first embodiment.

[0097] In contrast, the pilot-operated pressure regulating valve 300c according to the third embodiment is configured such that the axis Lm of the main valve section 100c is 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', that is, the intermediate pressure flow path length, can be made longer compared to the second embodiment, and the flow path at the bent section Bp can be bent by 180°. Therefore, in addition to cost reduction, space saving, and improved portability, as in the second embodiment, pressure fluctuations can be buffered even more efficiently.

[0098] As described above, in the third embodiment, similar 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 uppermost part of the intermediate pressure flow path), the conventional problem (reduction in the durability of the pressure-sensitive part due to pressure fluctuations of the primary side pressure) can be resolved and reliability can be improved.

[0099] Furthermore, in the third embodiment, similar to the second embodiment, pressure fluctuations can be more efficiently buffered by employing pressure fluctuation buffering means (1-1) (uneven portion on the surface defining the circumferentially extending gap) or pressure fluctuation buffering means (1-2) (multiple circumferential grooves on the surface defining the circumferentially extending gap). In addition, by employing pressure fluctuation buffering means (1-3) (maintaining the circumferentially extending gap with a biasing means), chattering can be suppressed and the desired valve opening flow rate in the main valve section 100c can be maintained. Moreover, by employing pressure fluctuation buffering means (2') (bent portion of the intermediate pressure flow path), pressure fluctuations can be more efficiently buffered 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 bent section Bp by 180°, the number of parts can be reduced, resulting in lower costs, space savings, improved portability, and even more efficient buffering of pressure fluctuations.

[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 to this configuration. For example, the main valve section 100c and the pilot section 200c may be formed as separate components.

[0102] (Fourth embodiment) A pilot-operated pressure regulating valve 300d according to the fourth embodiment of the present invention will be described with reference to Figure 8. The fourth embodiment differs 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 reference numerals are used for the same components, and redundant explanations are omitted.

[0103] As shown in Figure 7, in the pilot-operated pressure regulating valve 300c of the third embodiment, the intermediate pressure flow path length is secured by increasing the flow path length of the third fluid path 3', but there was still room to further extend the flow path length of the third fluid path 3'.

[0104] In contrast, the pilot-operated pressure regulating valve 300d according to the fourth embodiment has the axis Lm of the main valve section 100d and the axis Lp of the pilot section 200d arranged coaxially, and the valve opening direction of the main valve section and the valve opening direction of the pilot section are arranged in opposite directions. As a result, in the fourth embodiment, the length of the third fluid path 3' (see Figure 8(b)), that is, the length of the intermediate pressure flow path, can be made longer compared to the third embodiment. Therefore, in addition to cost reduction, space saving, and improved portability, as in the third embodiment, pressure fluctuations can be buffered even more efficiently.

[0105] As described above, in the fourth embodiment, similar 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 uppermost part of the intermediate pressure flow path), the conventional problem (reduction in the durability of the pressure-sensitive part due to pressure fluctuations of the primary side pressure) can be resolved and reliability can be improved.

[0106] Furthermore, in the fourth embodiment, similar to the third embodiment, pressure fluctuations can be more efficiently buffered by employing pressure fluctuation buffering means (1-1) (uneven portion on the surface defining the circumferentially extending gap) or pressure fluctuation buffering means (1-2) (multiple circumferential grooves on the surface defining the circumferentially extending gap). In addition, by employing pressure fluctuation buffering means (1-3) (maintaining the circumferentially extending gap with a biasing means), chattering can be suppressed and the desired valve opening flow rate in the main valve section 100d can be maintained. Moreover, by employing pressure fluctuation buffering means (2') (bent portion of the intermediate pressure passage), pressure fluctuations can be more efficiently buffered in the back pressure chamber 105c.

[0107] Furthermore, in the fourth embodiment, similar to the third embodiment, by ensuring the length of the intermediate pressure flow path and bending the flow path at the bent section Bp by 180°, the number of parts can be reduced, resulting in lower costs, space savings, improved portability, and even more efficient buffering of 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 the invention is not limited to this, and for example, the main valve section 100d and the pilot section 200d may be formed as separate parts. Also, in the fourth embodiment, the first joint pipe 1 and the second joint pipe 2 are arranged symmetrically around the axes Lm and Lp when viewed from the direction of the axes Lm and Lp, but the invention is not limited to this, and for example, the first joint pipe 1 and the second joint pipe 2 may be arranged in any circumferential position that does not intersect the third fluid path 3' when viewed from the direction of the axes Lm and Lp.

[0109] (Fifth embodiment) A pilot-operated pressure regulating valve 300e according to the fifth embodiment of the present invention will be described with reference to Figure 9. The fifth embodiment differs mainly in that it employs a manifold 120 in which the first fluid path 1' and the second fluid path 2' are formed, and the pilot valve seat member 230' and the main valve body 140' are in a nested structure, but the other basic configurations are the same as those of the fourth embodiment. Here, the same reference numerals are used for the same components, and redundant explanations are omitted.

[0110] As shown in Figure 8, in the pilot-operated pressure regulating valve 300d of the fourth embodiment, the length of the flow path of the third fluid path 3' has been extended, resulting in a relatively long overall length in the direction of the axes Lm and Lp. Therefore, when the pilot-operated pressure regulating valve 300d is connected to the first joint pipe 1 and the second joint pipe 2 at the installation site, for example, in the arrangement shown in Figure 8, a moment acts on the pilot-operated pressure regulating valve 300d that tends to tilt in a direction perpendicular to the direction in which the first joint pipe 1 and the second joint pipe 2 extend, that is, towards the front or back of the paper. As a result, a separate support structure for the pilot-operated pressure regulating valve 300d is required, and if this support structure is not provided, there is a concern that the connection between the valve body 110d and the first joint pipe 1 and the second joint pipe 2 may be damaged.

[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, in the pilot-operated pressure regulating valve 300e according to the fifth embodiment, the pilot valve seat member 230' and the main valve body 140' are nested together, allowing the overall length of the pilot-operated pressure regulating valve 300e in the axial direction Lm,Lp to be reduced compared to the fourth embodiment, thereby reducing the moment generated when the pilot-operated pressure regulating valve 300e attempts to collapse. As a result, in the pilot-operated pressure regulating valve 300e according to 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.

[0112] <About the configuration of a pilot-operated pressure regulating valve> A pilot-operated pressure regulating valve 300e according to the fifth embodiment of the present invention will be described with reference to Figures 9 and 10. The pilot-operated pressure regulating valve 300e consists of a main valve section 100e and a pilot section 200e, and is firmly fixed to the manifold 120 in which the first fluid path 1' and the second fluid path 2' are formed, by crimping or the like. From here on, the valve body 110e, the main valve section 100e, and the pilot section 200e will be described, focusing mainly on the differences from the fourth embodiment.

[0113] <About the valve body> The valve body 110e is made of a metal material such as stainless steel, is a hollow cylindrical member, and has a through hole that penetrates along the axes Lm and Lp. The main valve chamber 125, main valve guide hole 105b, back pressure chamber 105c, intermediate chamber 213, and bellows housing chamber 216 are provided in this through hole so as to be in communication with each other, and connect to the first fluid path 1' and the second fluid path 2', respectively. In addition, a pressure equalization port 113, a third fluid path 3', and a pilot inlet port 211 are provided at equal intervals in the circumferential direction around the axes Lm and Lp, and along the direction of the axes Lm and Lp, respectively, so as to maintain constant fluid communication between the back pressure chamber 105c and the intermediate chamber 213.

[0114] <Regarding the main body of the main valve department> The main valve body 140' comprises a main valve seat 140a' provided on one side, which is substantially cylindrical in shape and made of a resin material such as PTFE, and a piston portion 140b' which is cylindrical in shape and extends to the other side in the direction of the axis Lm, and is made of a metal material such as brass. The main valve seat 140a' is housed in an annular groove provided on one end of the piston portion 140b' and is fixed via a retaining member 141' (for example, a C-shaped ring), and is positioned to cover the main valve seat 105a of the manifold 120 when viewed from the direction of the axis Lm. The piston portion 140b' also has a through hole that penetrates along the axis Lm, and in this through hole, a main valve body through hole 140d' defining the fourth fluid path 4' and a sliding hole 140e' are provided so as to expand in diameter from one end to the other and communicate with each other. Furthermore, a locking portion 140c' is provided at the stepped portion between the main valve body through hole 140d' and the sliding hole 140e'. Here, the piston portion 140b' is positioned so as to be guided in the axial direction 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, thereby constantly biasing the main valve body 140' in the valve closing direction.

[0115] Regarding the movement of the main valve body 140' in the axial direction Lm, the locking portion 140c' comes into contact with the main valve body stopper portion 233' of the pilot valve seat member 230', thereby defining the maximum valve lift amount from the valve closed state to the fully open state, which is the maximum valve lift state of the main valve body 140'.

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

[0117] The pilot valve seat portion 231' has a pilot valve port 231a that extends along the axis Lp and has an annular pilot valve seat 231c formed at its other end, and a pilot outlet port 212' that has a larger inner diameter than the pilot valve port 231a and extends to one end. In addition, an annular groove for accommodating an O-ring 192 (biasing means) is provided on the outer circumferential surface of the pilot valve seat portion 231'. This outer circumferential surface (slide guide surface) of the pilot valve seat portion 231' guides the sliding of the main valve body 140' in the direction of the axis Lm.

[0118] The pilot guide portion 232' is cylindrical in shape and rises from around the other end of the pilot valve seat portion 231', and has a stepped portion formed on its outer circumference, on which a one-side spring receiving portion 208 is provided. The valve opening spring 206, sandwiched between this one-side spring receiving portion 208 and the other-side spring receiving portion 207 which engages with the pilot valve body 240, constantly biases the pilot valve body 240 in the valve opening direction.

[0119] <About the operation of pilot-operated pressure regulating valves> The operation of the pilot-operated pressure regulating valve 300e in the fifth embodiment will be explained using Figure 10. In the fifth embodiment, the opening and closing operations of the main valve section 100e and the pilot section 200e in states 1, 2, and 3, and the relational equations for the external forces acting on the main valve section 100e and the pilot section 200e, respectively, are the same as in the first embodiment, so a detailed explanation will be omitted. Furthermore, 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) (multiple circumferential grooves on the surface defining the circumferentially extending gap) are the same as in the first to fourth embodiments. Therefore, the explanation will mainly focus on the pressure fluctuation buffering means (1) (circumferentially extending gap), the pressure fluctuation buffering means (2) (circumferentially extending gap at the uppermost part 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) (maintaining the circumferentially extending gap with a biasing means).

[0120] (Condition 1: When the primary side pressure is lower than the valve opening pressure of the pilot unit) As shown in Figures 10(a) and (b), in the pilot-operated pressure regulating valve 300e, when the primary 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 both closed.

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

[0122] <Regarding pressure fluctuation buffering means (2) (circumferentially extending gap at the uppermost part of the intermediate pressure flow path)> In this embodiment, the pressure fluctuation buffering means (2) (circumferentially extending gap at the uppermost part of the intermediate pressure flow path) is configured to keep the main valve chamber 125 and the back pressure chamber 105c in constant communication only through the circumferentially extending gap Gc, as shown in Figure 9. Therefore, since the circumferentially extending gap Gc is provided on the uppermost part of the intermediate pressure flow path, which includes the back pressure chamber 105c, the third fluid path 3', and the bellows housing chamber 216, the pressure wave buffered by the circumferentially extending gap Gc can further buffer pressure fluctuations by passing through the entire length of the intermediate pressure flow path.

[0123] <Regarding the pressure fluctuation buffering means (2') (bent section of the intermediate pressure flow path)> As shown in Figure 9, this is a bend Bp provided in the intermediate pressure flow path from the back pressure chamber 105c to the third fluid path 3'. Specifically, the pressure wave propagating from the back pressure chamber 105c to the third fluid path 3' first collides with the valve body 110e at the bend Bp where the flow path bends 90° as it propagates from the back pressure chamber 105c to the third fluid path 3', then repeatedly collides within the back pressure chamber 105c, and finally propagates to the third fluid path 3' in a buffered state. As a result, the pressure wave can more efficiently buffer pressure fluctuations in the back pressure chamber 105c at the bend Bp.

[0124] (Condition 2: When the primary side pressure is higher than the valve opening pressure of the pilot valve, but lower than the valve opening pressure of the main valve) As shown in Figures 10(c) and (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 closed state while the pilot section 200e is in an open state. At this time, the pilot valve body 240 of the pilot section 200e moves in the valve opening direction (see arrow M1' in Figure 10(d)).

[0125] Furthermore, similar to state 1, by simultaneously employing pressure fluctuation buffering means (1) (circumferentially extending gap Gc) and pressure fluctuation buffering means (2) (circumferentially extending gap at the uppermost part of the intermediate pressure flow path), pressure fluctuations can be reliably buffered 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 through the third fluid path 3' to the bellows housing chamber 216.

[0126] (Condition 3: When the primary side pressure is higher than the valve opening pressure of the main valve) As shown in Figures 10(e) and (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 each open. At this time, first, the pilot valve body 240 of the pilot section 200e moves further in the valve opening direction (see arrow M2' in Figure 10(f)), causing the main valve body 140' of the main valve section 100e to move in the valve opening direction (see arrow M3' in Figure 10(e)), and the locking portion 140c' comes into contact with the main valve body stopper portion 233', thereby maintaining the fully open state of the main valve body 140'.

[0127] <Regarding pressure fluctuation buffering means (1-3) (maintaining the circumferentially extending gap with a biasing means)> In this embodiment, the pressure fluctuation buffering means (1-3) (maintaining the circumferentially extending gap by a biasing means) is an O-ring 192 (biasing means) provided between the main valve body 140' and the outer circumferential surface (slide guide surface) of the pilot valve seat portion 231', as shown in Figure 10(e), which biases the axis of the main valve body 140' to be along the axis Lm direction. The outer circumferential surface of the pilot valve seat portion 231' is formed concentrically with the axis Lm. The elastic force of this O-ring 192 suppresses oscillations occurring in the main valve body 140', making the circumferentially extending gap Gc a continuous and consistently uniform gap in the circumferential direction. Furthermore, the sliding resistance of the O-ring 192 suppresses chattering occurring in the main valve body 140', making it possible to maintain the desired valve opening flow rate in the main valve portion 100e.

[0128] As described above, in the fifth embodiment, similar to the fourth embodiment, by simultaneously employing pressure fluctuation buffering means (1) (circumferentially extending gap) and pressure fluctuation buffering means (2) (circumferentially extending gap at the uppermost part of the intermediate pressure flow path), the conventional problem (reduction in the durability of the pressure-sensitive part due to pressure fluctuations of the primary side pressure) can be resolved and reliability can be improved.

[0129] Furthermore, in the fifth embodiment, similar to the fourth embodiment, pressure fluctuations can be more efficiently buffered by employing pressure fluctuation buffering means (1-1) (uneven portion on the surface defining the circumferentially extending gap) or pressure fluctuation buffering means (1-2) (multiple circumferential grooves on the surface defining the circumferentially extending gap). In addition, by employing pressure fluctuation buffering means (1-3) (maintaining the circumferentially extending gap with a biasing means), chattering can be suppressed and the desired valve opening flow rate in the main valve section 100e can be maintained. Moreover, by employing pressure fluctuation buffering means (2') (bent portion of the intermediate pressure passage), pressure fluctuations can be more efficiently buffered 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 making the pilot valve seat member 230' and the main valve body 140' nested, the overall length in the axial direction Lm,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 pressure fluctuation buffering means (1) (circumferentially extending gap) and pressure fluctuation buffering means (2) (circumferentially extending gap at the uppermost part of the intermediate pressure flow path), all of the following are employed: pressure fluctuation buffering means (1-1) (irregular portion on the surface defining the circumferentially extending gap) or pressure fluctuation buffering means (1-2) (multiple circumferential grooves on the surface defining the circumferentially extending gap), pressure fluctuation buffering means (1-3) (maintaining the circumferentially extending gap with a biasing means), and pressure fluctuation buffering means (2') (bent portion of the intermediate pressure flow path), but is not limited to these. For example, if at least pressure fluctuation buffering means (1) (circumferentially extending gap) and pressure fluctuation buffering means (2) (circumferentially extending gap at the uppermost part of the intermediate pressure flow path) are employed simultaneously, then none of the pressure fluctuation buffering means (1-1) (irregularities on the surface defining the circumferentially extending gap) or pressure fluctuation buffering means (1-2) (multiple circumferential grooves on the surface defining the circumferentially extending gap), pressure fluctuation buffering means (1-3) (maintaining the circumferentially extending gap with a biasing means), or pressure fluctuation buffering means (2') (bent portion of the intermediate pressure flow path) are employed, or a combination including at least one of them is employed.

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

[0133] It goes without saying that the pilot-operated pressure regulating valves 300a, 300b, 300c, 300d, and 300e of this embodiment are applicable not only to the exemplified refrigerant circuits but to all fluid devices and fluid circuits. Furthermore, the present invention is not limited to the above-described forms, embodiments, or modifications, and can be appropriately modified or altered without departing from the technical spirit 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 Equalization 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 threaded section 162b Main valve stopper section 163 Main valve spring 191 Leaf spring (biasing means) 192 O-ring (biasing means) 200a, 200b, 200c, 200d, 200e Pilot Unit 205 Pilot Unit 206 Valve opening spring 207 Other side spring support 208 One-sided spring support 210 Pilot valve housing 211 Pilot Inflow Port 212,212' Pilot Outlet Port 213 Intermediate Room 215 Pilot valve chamber 216 Bellows housing chamber (pressure-sensitive unit housing chamber) 218 One-sided spring support 220 spring case 221 Spring containment chamber 222 Female thread section 230,230' Pilot valve seat member 231,231' Pilot valve seat section 231a Pilot valve port 231b Internal passage 231c Pilot valve seat 232,232' Pilot Guide Section 232a Radial communication hole 233' Main valve stopper section 240 Pilot valve body 241 Pilot valve section 242 Pilot guide shaft 242a Annular groove 250 pressure-sensitive units 251 Pressure-sensitive bellows (pressure-sensitive part) 253 Bellows top cover 253a Through hole 253b Bellows upper cover joint 253c Contact part 255 Connecting rod 255a Large diameter section 255b Small diameter section 255c Step section 255d Flange section 260 Adjustable spring unit 261 Spring support member 261a Boss section 261b Tsubabe 262 Adjustment screw member 262a Annular wall section 262b Top part 262c Male threaded section 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 the piston section 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 Biasing force of the valve opening spring Fp2: Biasing force due to the pressure-sensitive bellows itself Fp3 Adjustment spring biasing force Lm Main valve axis Lp pilot section axis M1,M1',M2,M2',M3,M3' Valve opening direction P1 Primary pressure P1' Intermediate pressure P2 Secondary pressure Pmo Main valve opening pressure Ppo pilot valve opening pressure Pre-relief pressure Q Flow rate of the working fluid Sm1 Pressure-receiving area of ​​the piston section Sm2 Main valve seat pressure receiving area Sp1 Effective pressure-receiving area of ​​pressure-sensitive bellows Sp2 Pilot valve pressure receiving area

Claims

1. A main valve section comprising: 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 body that can abut against or separate from the main valve seat; a main valve guide hole that guides the main valve body in the axial direction; a back pressure chamber provided on the opposite side of the main valve chamber, sandwiching the main valve body; a pressure fluctuation buffering means that keeps the main valve chamber and the back pressure chamber in constant communication and buffers pressure fluctuations from the main valve chamber to the back pressure chamber; and a pressure equalization port communicating with the back pressure chamber. A pilot unit comprising: a pressure-sensitive element; a pressure-sensitive element housing chamber for housing the pressure-sensitive element; a pilot inlet port communicating with the pressure-sensitive element housing chamber; a pilot valve port communicating with the pressure-sensitive element housing chamber via a pilot valve seat; and a pilot valve body connected to the pressure-sensitive element and capable of contacting or separating from the pilot valve seat in accordance with the displacement of the pressure-sensitive element; A fluid path connecting the pressure equalization port and the pilot inlet port, and 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 maintains constant communication between the main valve chamber and the back pressure chamber and the pressure-sensitive part housing chamber, solely through the circumferentially extending gap. A pilot-operated pressure regulating valve, wherein the pressure-sensitive part senses 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 unit, the pressure of the back pressure chamber and the pressure of the main valve chamber become the same; when the pressure is higher than the valve opening pressure of the pilot unit and lower than the valve opening pressure of the main valve unit, a differential pressure is created 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 unit, the differential pressure between the back pressure chamber and the main valve chamber causes the main valve body to open.

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

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

4. The pilot-operated pressure regulating valve according to claim 1, characterized in that the pressure fluctuation buffering means is provided between a slide guide surface formed concentrically with the axis at a position spaced apart from the circumferentially extending gap and the main valve body, and is a biasing means that biases the axis of the main valve body to be aligned with the axial direction.

5. The pilot-operated pressure regulating valve according to claim 1, characterized in that the pressure fluctuation buffering means is a bent portion formed in the flow path from the back pressure chamber to the pressure-sensitive element housing chamber.

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