JPH07113405A - Slow start valve - Google Patents

Abstract

PURPOSE:To enable one pilot throttle valve to be used in common to every value regardless of the sizes of the pressure reducing valve of a main value, and suppress generation of stick slip phenomenon by an easily adjustable slow start valve even if starting friction is different from dynamic friction. CONSTITUTION:A feed valve seat 4 and an exhaust valve seat 3 are provided with their back surfaces facing each other in a valve body 10 provided with P port and A port, a feed valve body 2 and an exhaust valve body 1 for opening/closing those valve seats 4, 3 are energized in valve closing direction by guide springs 19, 18 respectively, and a large diameter part 24 is provided on a valve shaft 23 insorted through those valve bodies 2, 1. The top end part 27 of the valve shaft 23 is fixed to a pressure receiving body which is displaceable in axial direction for partitioning a pilot chamber 28 and a main feed back chamber 29, the pilot chamber 28 is communicated with the P port, and the main feed back chamber 29 is communicated with the A port. A throttle valve and a check valve are provided is parallel in a passage for communicating the P port and the Pilot chamber 28 with each other so as to regulate the flow amount of gas which flows from the P port to the pilot chamber 28.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used in pneumatic equipment for actuating actuating members of various machines by means of an air actuator, and when the pressure on the exhaust side of the air actuator is below a predetermined pressure (for example, atmospheric pressure). The present invention relates to a slow start valve for preventing a runaway runaway.

[0002]

2. Description of the Related Art In an air actuator after the supply of compressed air has been stopped for a long time or after residual pressure is removed, the pressure on the exhaust side is below a predetermined pressure (for example, atmospheric pressure). If you supply, the piston and the like may jump out and run away. As a countermeasure,
A slow start device shown in FIG. 4 (Japanese Patent Laid-Open No. 50-1531)
It is considered that the meter-in control is performed by using the Japanese Patent No. 88). In FIG. 4, the air pressure source 100 is a supply valve.
The solenoid valve 103 is communicated with the solenoid valve 103 through the safety valve 102, the throttle valve 107, and the air cylinder 104 through the A and B ports of the solenoid valve 103 through the check valve-equipped flow rate adjusting valves 105 and 106, respectively.
Connected to the port. When the supply valve 101 is switched to the position I after stopping the supply of compressed air for a long time, the compressed air is supplied from the air pressure source 100 to the supply valve 101, the throttle 107, the B port of the electromagnetic switching valve 103, the flow control valve with a check valve. It is supplied to the working chamber on the rod side of the air cylinder 104 through 106. At this time, since the pressure of the working chamber on the head side (exhaust side) of the air cylinder 104 is equal to or lower than a predetermined pressure, the flow control valve 10 with check valve is
Although 5 does not substantially function, the flow rate of the compressed air is adjusted by the throttle 107, and the piston of the air cylinder 104 is slowly started by the meter-in control. When the stroke end is reached without causing shock, the pressure in the rod-side working chamber and passage of the air cylinder 104 rises, and the safety valve 102 consisting of the spring offset pilot type 2-port 2-position switching valve moves to the open position. A large amount of compressed air can pass through the safety valve 102. When the electromagnetic switching valve 103 is switched in this state, a large flow rate of compressed air is supplied, and thereafter, normal meter-out control is performed.

In an air cylinder, the starting friction when a stationary piston starts moving in the cylinder is larger than the dynamic friction. Therefore, if meter-in control is performed using the throttle 107, stick-slip occurs and the moving speed of the piston is increased. Is not constant. The throttle was not a variable throttle, and the throttle was gradually opened at startup, but in the case of meter-in control,
Since the throttle amount and the moving speed of the piston are not proportional to each other, the occurrence of stick-slip cannot be prevented. It was considered to reduce stick-slip by changing the structure of the main valve, but in order to make it easier to adjust the throttle amount, it is necessary to devise the stroke and opening of the main valve, and the structure of the main valve is complicated. Becomes

[0004]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned drawbacks of the prior art, and allows one pilot throttle valve to be used in common regardless of the size of the pressure reducing valve of the main valve, and adjustment is possible. An object of the present invention is to suppress the occurrence of stick-slip phenomenon by a slow start valve that is easy to perform even if the starting friction and the dynamic friction are different.

[0005]

In order to achieve the above object, the present invention provides a supply valve seat (4) and an exhaust valve seat in a valve body (10) having a P port, an A port and an R port. The guide valve (19) and (18) are respectively provided with the supply valve body (2) and the exhaust valve body (1) which are formed by arranging (3) so as to face each other and opening and closing these valve seats (4) and (3). ) To urge the valve in the valve closing direction,
A pair of valve bodies on the valve shaft (23) inserted through (2) and (1)
A large-diameter portion (2) that engages with one valve element to open it due to the axial displacement of the valve shaft (23) is located between (2) and (1).
4) is provided, and the tip (27) of the valve shaft (23) is placed in the pilot chamber.
(28) and the main feedback chamber (29) are fixed to the axially displaceable pressure receiving body, the pilot chamber (28) communicates with the P port, and the main feedback chamber (29) communicates with the A port. In the start valve, a throttle and a check valve are provided in parallel in a passage that connects the P port and the pilot chamber (28), and the flow rate from the P port to the pilot chamber (28) is adjusted. Further, in the slow start valve, the central passageway (38) of the check valve guide (37)
A large diameter opening (70) is formed at the rear end of the needle, a small diameter portion (67) and a large diameter portion (66) are formed at the needle portion (44), and the small diameter portion (67) located at the tip end is in the axial direction. The axial length of the large diameter portion (66) is made larger than the length, and the first stage throttle is formed by the small diameter portion (67) and the central passage (38), the large diameter portion (66) and the large diameter opening portion (70). 2nd stage diaphragm by
The small-diameter portion (67) and the large-diameter opening portion (70) are provided with a diaphragm capable of three-stage diaphragm adjustment of the third-stage diaphragm.
In interpreting the present invention, the following matters should be considered. The A port is a port that communicates with an air actuator (for example, an air cylinder, an air motor), the P port is a port that communicates with a compressed air source, and the R port is a port that communicates with the atmosphere. In the present invention, the term compressed air means all gases (including air and nitrogen gas) having a predetermined pressure. In the present invention, pilot type pressure reducing valves shall include poppet valves, spool valves and other types of valves, and pilot operating means shall include pistons, diaphragms and other means.

[0006]

The compressed air supplied to the P port has its flow rate adjusted by the throttle and gradually flows into the pilot chamber, and the pressure in the pilot chamber gradually rises. Due to the action of the pilot type pressure reducing valve,
The pressure in the A port rises slowly, and the air actuator communicated with the A port slowly starts.

[0007]

1 shows a slow start valve of a first embodiment of the present invention. Slow start valve has a valve body 1
0, the cylinder body 11, the spacer 12, and the pilot body 13 are sequentially connected in the longitudinal direction (vertical direction in FIG. 1), and a gasket is sandwiched between the valve body 10, the cylinder body 11, and the spacer 12. Has been done. The valve body 10 has a stepped space that penetrates in the longitudinal direction, and a secondary pressure chamber 14 is formed in the center of the space, and the cylinder body
The cylindrical projection 15 of the cylinder body 11 is fitted into the large diameter portion on the 11 side (upper side), and the cup-shaped stepped valve guide 16 is inserted into the stepped hole on the opposite side (lower side). . Stepped Hole and Valve Guide 16
An O-ring is interposed between and, and the valve guide 16 is fixed by a C-shaped retaining ring 17. Exhaust valve body 1 having a substantially cup shape and a poppet valve on the inner peripheral surfaces of the cylindrical protruding portion 15 and the valve guide 16.
And the supply valve body 2 are slidably fitted to each other, and O-rings are respectively provided between the inner circumferential surfaces of the cylindrical projection 15 and the valve guide 16 and the outer circumferences of the exhaust valve body 1 and the skirt portion of the supply valve body 2. Is provided. The exhaust valve body 1 and the supply valve body 2 are respectively the first
It is pressed toward the exhaust valve seat 3 and the supply valve seat 4 by the guide spring 18 and the second guide spring 19. An exhaust chamber 20 and a primary pressure chamber are provided outside the exhaust valve body 1 and the supply valve body 2.
21 are formed respectively, and as shown in FIG. 1, the exhaust valve body 1
When the seal of the supply valve body 2 and the seal of the supply valve body 2 are in contact with the exhaust valve seat 3 and the supply valve seat 4, respectively, between the exhaust chamber 20 and the secondary pressure chamber 14 and between the secondary pressure chamber 14 and the primary pressure chamber 21. The spaces are closed. The A port on one side (left side) of the valve body 10 is the secondary pressure chamber.
The B port on the other side (right side) of the valve body 10 is communicated with the primary pressure chamber 21. Further, the exhaust chamber 20 has an R (not shown).
It communicates with the atmosphere through a port (exhaust port).

The valve shaft 23 has a tip portion 27 and a first small diameter portion.
25, a large diameter portion 24 and a second small diameter portion 26 are integrally connected, the first small diameter portion 25 is inserted into the central hole of the exhaust valve body 1, and the second small diameter portion 26 is the center of the supply valve body 2. It is inserted through the hole. The pressure adjusting piston 22 (pressure receiving body) is provided in the cylinder hole of the cylinder body 11.
Is slidably fitted, the tip portion 27 of the valve shaft 23 is inserted into the center hole of the pressure regulating piston 22, and an O-ring is interposed between the center hole of the pressure regulating piston 22 and the tip portion 27. , Tip 27
Is fixed by a hexagon nut. A plurality of communication holes are formed around the central holes of the exhaust valve body 1 and the supply valve body 2. When the valve shaft 23 is moved to the exhaust valve body 1 side, the large diameter portion 24 opens the exhaust valve body 1. , Valve shaft 23 supply valve body 2
When it moves to the side, the large-diameter portion 24 opens the supply valve body 2. The first small diameter portion 25 is inserted into the center hole of the side wall 55 of the cylinder body 11, and an O-ring is arranged between the first small diameter portion 25 and the center hole of the side wall 55. 2 on the outer peripheral surface of the pressure regulating piston 22
A wear ring 56 and a piston packing 57 are fitted in the two annular grooves, and a relief spring 58 is interposed between the pressure adjusting piston 22 and the side wall 55. The feedback chamber 29 on the lower side (valve body 10 side) of the pressure regulating piston 22 is communicated with the A port via the feedback passage 30, and the pilot chamber 28 on the upper side (spacer 12 side) of the pressure regulating piston 22 is the first chamber of the spacer 12. It is communicated with the two communication passages 32. The P port is connected to the spacer 12 via the passage 33 of the valve body 10 and the passage 34 of the cylinder body 11.
To the first communication passage 31. The valve body 10 and the cylinder body 11 constitute a pilot type pressure reducing valve. Although the poppet valve is used as the pilot type pressure reducing valve in the first embodiment, a spool valve or the like may be used, and the pressure adjusting piston may be changed to a diaphragm.

The pilot body 13 has a cylindrical valve chamber 35.
And a screwing hole 36 having a larger diameter than that is formed adjacently, and the screwing hole 36 is opened to the other side (right side in FIG. 1) of the pilot body 13. A check valve guide 37 is inserted in the cylindrical valve chamber 35, and a central passage 38 and a plurality of radial passages 39 are formed in the check valve guide 37 in a communicating state. The male threaded portion at the tip of the needle guide 40 is screwed into the screwing hole 36, the tip of the needle guide 40 contacts the check valve guide 37, and the threaded portion at the open end of the screwing hole 36 and the needle guide 40
An O-ring is interposed between the non-screwed part and the. A stepped hole is formed in the needle guide 40, and the tip side (left side in FIG. 1) of the stepped hole becomes a large diameter hole 41 and the rear end side becomes a small diameter portion 42. The needle valve body 43 is inserted through this stepped hole,
Has a needle part 44, a large diameter part 45, and a sliding part 46.
The 45 and the sliding portion 46 are respectively slidable with the large diameter hole 41 and the small diameter portion 42 of the needle guide 40, and an O-ring is fitted in the annular groove of the large diameter portion 45. The proximal end of the needle valve body 43 (see FIG.
The central hole of a substantially cup-shaped adjustment knob 47 is fitted to the stepped portion at the right end portion), and the adjustment knob 47 is fixed by a retaining ring. The female screw portion on the inner circumference of the skirt portion of the adjusting knob 47 is screwed into the male screw portion of the needle guide 40, and the needle valve body 43 is moved in the axial direction by the rotation of the adjusting knob 47.

An annular chamber 50 at the tip of the needle guide 40 is provided with a first passageway 51 in the pilot body 13 through which a first spacer 12 is formed.
An O-ring for communicating with the communication passage 31 is provided at a connecting portion between the passage 51 and the first communication passage 31 for preventing leakage. The tip portion (the left end portion in FIG. 1) of the central passage 38 of the check valve guide 37 is connected to the second communicating passage of the spacer 12 via the passage 52 in the pilot body 13.
An O-ring for communication with 32 is provided at a connecting portion between the passage 52 and the second communicating passage 32 for preventing leakage. An annular groove 48 is formed on the outer circumference of the check valve guide 37, and the annular groove 48 is provided through a gap between the outer peripheral portion on one side (left side in FIG. 1) of the check valve guide 37 and the inner wall of the valve chamber 35. The check valve guide 37 is communicated with the annular chamber 50 via the annular communication portion 53 on the other side (right side in FIG. 1). A check valve 49 having a V-shaped cross section and made of an elastic body is fitted in the annular groove 48. The check valve 49 allows air to flow from the radial passage 39 to the communicating portion 53, but flows in the opposite direction. Will stop. A throttle (hereinafter referred to as “throttle S”) is formed between the tapered needle portion 44 and the central passage 38 of the check valve guide 37, and the position thereof is determined by the rotation of the adjustment knob 47, and the adjustment knob 47.
The position of is maintained by the nut 60. The passage 51 communicates with the central passage 38 via the annular chamber 50, the slit 61, and the diaphragm S at the tip of the needle guide 40. In this way, the throttle S and the check valve 49 are fluidly in parallel. In addition,
In the first embodiment, the throttle S and the check valve 49 are arranged on the same coaxial line, but a normal throttle and check valve may be arranged in parallel.

The operation of the slow start valve of the first embodiment will be described. As in the case of FIG. 4, the supply valve is connected to the P port of the valve body 10, the electromagnetic switching valve is connected to the A port, and after stopping the supply of compressed air for a long time, the supply valve is switched to the P port. Supply compressed air to. Initially, the pressures in the pilot chamber 28 and the feedback chamber 29 are below a predetermined pressure (for example, atmospheric pressure), the valve shaft 23 is in the neutral position in the drawing, and the exhaust valve body 1 and the supply valve body 2 are closed.
Compressed air does not flow from P port to A port. Compressed air is supplied from the P port to the passages 33 and 34, the first communication passage 31, and the passage 5
1, passing through the annular chamber 50 and the slit 61, is narrowed down by the diaphragm S between the needle portion 44 and the central passage 38, and the central passage 38, the passage 52,
It flows into the pilot chamber 28 through the second communication passage 32. As the pilot pressure in the pilot chamber 28 rises, the pressure adjusting piston 22 moves downward, the supply valve body 2 opens, and the compressed air becomes P
Flow from the port to the electromagnetic switching valve through the primary pressure chamber 21, the gap between the supply valve body 2 and the supply valve seat 4, the secondary pressure chamber 14, and the A port. As a function of the slow start valve, the secondary pressure is transmitted to the feedback chamber 29 through the feedback passage 30, and when the secondary pressure reaches the pressure corresponding to the pilot pressure, the supply valve body 2 is closed and the secondary pressure is the pilot pressure. The pressure is maintained according to the pressure. Actually, the compressed air gradually flows into the pilot chamber 28 through the throttle S, and the pilot pressure gradually rises. Therefore, the pressure of the compressed air flowing out from the A port also gently rises, and the pressure of the compressed air supplied to the air cylinder also gently rises. Therefore, the air cylinder is operated without causing a stick slip. When the stroke end is reached without impact, the pressure in port A rises and is maintained at the set value, after which normal operation occurs. When the supply valve is switched in an emergency or the like, the P port of the valve body 10 is communicated with the atmosphere, and the air in the pilot chamber 28 becomes the second communication passage 32, the passage.
52, central passage 38, radial passage 39, check valve 49, communication part
53, annular chamber 50, passage 51, first communication passage 31, passages 34 and 33, P
It is quickly discharged into the atmosphere through the port and supply valve.
The pressure adjusting piston 22 moves upward in response to the decrease in pilot pressure, the exhaust valve body 1 is opened, and the air in the air cylinder is supplied to the solenoid switching valve, the port A of the valve body 10, the secondary pressure chamber 14,
It is rapidly discharged into the atmosphere through the gap between the exhaust valve body 1 and the exhaust valve seat 3 and the exhaust port.

FIG. 2 (a) is a longitudinal sectional view of an essential part of a modified example of the diaphragm portion of the first embodiment of FIG. 1, and FIG.
The same reference numerals as in FIG. 1 are used for the same portions as. A large diameter opening 70 is formed at the rear end of the central passage 38 of the check valve guide 37 (right end in FIG. 2 (a)), and the front end of the large diameter opening 70 (FIG. 2 (a)) is formed.
And the left end) and the central passage 38 are connected by a truncated cone. A large-diameter portion 66 is formed on the needle portion at the tip of the needle valve body 43 via a small-diameter portion 67 on the tip side and a step portion, and the shaft of the large-diameter portion 66 is larger than the axial length of the small-diameter portion 67 located at the tip. Increase the direction length. The outer diameter of the small diameter portion 67 is made slightly smaller than the inner diameter of the central passage 38, and the outer diameter of the large diameter portion 66 is made slightly smaller than the inner diameter of the large diameter opening 70 and larger than the inner diameter of the central passage 38.
The small diameter portion 67 or the large diameter portion 66 of the needle portion at the tip of the needle valve body 43 is inserted into the large diameter opening portion 70 of the check valve guide 37 and the central passage 38. By rotating the adjustment knob 47, the tip of the needle valve body 43 moves axially,
(a) The throttle size between the annular chamber 50 and the central passage 38 is adjusted at any position of the strokes indicated by-in FIG. During the stroke, the flow rate is adjusted in the narrowest gap (first stage throttle) between the small diameter portion 67 of the needle valve element 43 and the central passage 38 of the check valve guide 37,
During the stroke, the flow rate is adjusted in the middle gap (second stage throttle) between the large diameter portion 66 of the needle valve body 43 and the large diameter opening 70 of the check valve guide 37, and during the stroke, The flow rate is adjusted in the widest gap (third stage throttle) between the small diameter portion 67 of the needle valve element 43 and the large diameter opening 70 of the check valve guide 37. The relationship between the stroke of the needle valve element 43 and the opening of the throttle is as shown in FIG. 2 (b).
The size of the pressure reducing valve also changes depending on the size of the actuator used on the A port side, but since the pilot throttle can be adjusted in three stages, one pilot can be used for pressure reducing valves (pilot valves) of different sizes. Can be commonly used in valves.

FIG. 3 shows a slow start valve according to a second embodiment of the present invention. In the second embodiment, the same parts as those in the first embodiment shown in FIGS. 1 and 2 are designated by the same reference numerals and their description is omitted. The passage 34 of the cylinder body 11 is communicated with the p port of the solenoid valve 63 via the first communication passage 31 of the spacer 12, and the a port of the solenoid valve 63 is communicated with the passage of the pilot body 13 via the third passage 64 of the spacer 12. Connected to 51. Although the solenoid valve 63 is indicated by a symbol in FIG. 3, the solenoid valve 63 is actually connected to the spacer 12 like the pilot body 13. The rest of the configuration is similar to that of the first embodiment. In the second embodiment, the solenoid valve 63 has the position I.
In the case of, the p port and the a port communicate with each other, and the same operation as in the first embodiment is performed. In the second embodiment, when the solenoid valve 63 is switched to the position II, the air in the pilot chamber 28 becomes the second
Communication passage 32, passage 52, central passage 38, radial passage 39, check valve 49, communication portion 53, annular chamber 50, passage 51, third passage 64, a
It is quickly discharged into the atmosphere through the port and p port. If you want to inspect the air cylinder or the control device, you can switch the solenoid valve 63 to position II and bleed air.
It is convenient. The remaining operation is similar to that of the first embodiment.

[0014]

The compressed air supplied to the P port has its flow rate adjusted by the throttle and gradually flows into the pilot chamber, and the pressure in the pilot chamber gradually rises. Due to the action of the pilot type pressure reducing valve, the pressure at the A port gradually rises as the pressure inside the pilot chamber rises. Therefore, even if the starting friction and the dynamic friction differ, the air actuator communicated with the A port starts slowly without causing a stick slip. Since the pilot throttle can be adjusted in three stages, one pilot valve can be used in common even if the size of the pressure reducing valve of the main valve changes.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a slow start valve according to a first embodiment of the present invention.

FIG. 2 (a) is a longitudinal sectional view of an essential part of a modified example of the throttle portion of the first embodiment of the present invention, and FIG. 2 (b) shows the relationship between the stroke and the opening of the throttle. There is a figure.

FIG. 3 is a vertical sectional view of a slow start valve according to a second embodiment of the present invention.

FIG. 4 is a circuit diagram of a conventional slow start device.

[Explanation of symbols]

 1 Exhaust valve body 2 Supply valve body 3 Exhaust valve seat 4 Supply valve seat 10 Valve body 18 First guide spring 19 Second guide spring 23 Valve shaft 27 Tip 28 Pilot chamber 29 Main feedback chamber 37 Check valve guide 38 Central passage 44 Needle 66 Large diameter 67 Small diameter 70 Large opening

[Procedure amendment]

[Submission date] December 27, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0012

[Correction method] Change

[Correction content]

FIG. 2 (a) is a longitudinal sectional view of an essential part of a modified example of the diaphragm portion of the first embodiment of FIG. 1, and FIG.
The same reference numerals as in FIG. 1 are used for the same portions as. A large diameter opening 70 is formed at the rear end of the central passage 38 of the check valve guide 37 (right end in FIG. 2 (a)), and the front end of the large diameter opening 70 (FIG. 2 (a)) is formed.
And the left end) and the central passage 38 are connected by a truncated cone. On the needle portion 44 at the tip of the needle valve body 43, a large diameter portion 66 is formed via a small diameter portion 67 and a step portion on the tip side, and the diameter of the large diameter portion 66 is larger than the axial length of the small diameter portion 67 located at the tip. Increase the axial length. The outer diameter of the small diameter portion 67 is made slightly smaller than the inner diameter of the central passage 38, and the outer diameter of the large diameter portion 66 is made slightly smaller than the inner diameter of the large diameter opening 70 and larger than the inner diameter of the central passage 38. The small diameter portion 67 or the large diameter portion 66 of the needle portion 44 at the tip of the needle valve body 43 is inserted into the large diameter opening portion 70 of the check valve guide 37 and the central passage 38. By rotating the adjusting knob 47, the tip of the needle valve element 43 moves in the axial direction and is positioned at any one of the strokes indicated by to in FIGS. 2 (a) and 2 (b), The size of the throttle between the chamber 50 and the central passage 38 is adjusted. During the stroke, the flow rate is adjusted in the narrowest gap (first stage throttle) between the small diameter portion 67 of the needle portion 44 at the tip of the needle valve body 43 and the central passage 38 of the check valve guide 37. The flow rate is adjusted in the middle gap (second stage throttle) between the large diameter portion 66 of the needle portion 44 at the tip of the needle valve body 43 and the large diameter opening portion 70 of the check valve guide 37, and the stroke At this time, the flow rate is adjusted in the widest gap (third stage throttle) between the small diameter portion 67 of the needle portion 44 at the tip of the needle valve body 43 and the large diameter opening portion 70 of the check valve guide 37. The relationship between the stroke of the needle valve element 43 and the opening of the throttle is as shown in FIG. 2 (b). The size of the pressure reducing valve also changes depending on the size of the actuator used on the A port side, but since the pilot throttle can be adjusted in three stages, one pilot can be used for pressure reducing valves (pilot valves) of different sizes. Can be commonly used in valves.

[Procedure Amendment 2]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 1

[Correction method] Change

[Correction content]

[Figure 1]

[Procedure 3]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 2

[Correction method] Change

[Correction content]

[Fig. 2]

[Procedure amendment 4]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 3

[Correction method] Change

[Correction content]

[Figure 3]

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Akihiko Okada 6-43 Kakimoto-cho, Toyota-shi, Aichi SMC Corporation Toyota Sales Office (72) Inventor Akira Izumi Toyota-cho, Toyota-shi, Aichi Toyota Motor Corporation Within

Claims (2)

[Claims] 1. A supply valve body and an exhaust gas in which a supply valve seat and an exhaust valve seat are formed so as to face each other in a valve body having a P port, an A port, and an R port, and these valve seats are opened and closed. Each valve body is biased by a guide spring in the valve closing direction,
A large-diameter portion that engages with one valve body and opens it with axial displacement of the valve shaft is provided in the portion between the pair of valve bodies on the valve shaft that is inserted through those valve bodies. In a pilot type pressure reducing valve in which the tip of the shaft is fixed to an axially displaceable pressure receiving body that divides the pilot chamber and the main feedback chamber, the pilot chamber is communicated with the P port, and the main feedback chamber is communicated with the A port, A slow start valve characterized in that a throttle and a check valve are provided in parallel in a passage communicating between the P port and the pilot chamber, and a flow rate from the P port to the pilot chamber is adjusted. 2. A check valve guide having a large-diameter opening at the rear end of the central passage and a small-diameter portion and a large-diameter portion at the needle portion, which are larger than the axial length of the small-diameter portion at the tip. The axial length of the diametrical portion is increased, and the first-stage aperture is formed by the small-diameter portion and the central passage, the second-stage aperture is formed by the large-diameter portion and the large-diameter opening,
The slow start valve according to claim 1, further comprising a throttle capable of three-stage throttle adjustment of the third stage throttle by the small diameter portion and the large diameter opening portion.