JPH10283036A - Pressure reducing valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pressure reducing valve suitable for an air machine tool. SOLUTION: Concerning the valve element of a pressure reducing valve 21, a piston part 25a is formed at the lower part of a disk 25d and the piston part is inserted into the cylinder part 22a of a housing. The outer diameter of the disk 25d and the outer diameter of a valve seat 30 are almost equal to each other, and primary pressure p1 is operated only upon a pressure receiving surface S4 of small area on the lower surface of the disk 25d. The valve element 25 is opened/closed by balancing a pressure sum F2 +(S1 .P2 )+(S4 .P1 ) of spring force F2 of compression spring 28, secondary pressure S1 .P2 to a diaphragm 27 and primary pressure S4 .P1 to the disk 25d and spring force F1 of pressure regulation spring 29 and controlled into secondary pressure = set pressure. When the primary pressure is canceled in the state of secondary pressure = set pressure, the primary pressure S4 .P1 of disk 25d is reduced, the valve element 25 is opened and secondary side pressure air is discharged from an inlet.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure reducing valve, and more particularly to a pressure reducing valve suitable for adjusting the air pressure of a pneumatic tool.

[0002]

2. Description of the Related Art A conventional pressure reducing valve used in a pneumatic circuit will be described with reference to FIGS. FIG. 4 shows the structure of the direct-acting pressure reducing valve 1. A valve body 5 composed of a disk 5a and a stem 5b is provided in a passage between an inlet 3 and a pressure reducing outlet 4 of a valve housing 2, and a secondary pilot chamber 6 is provided. The diaphragm 7 inserted into the stem 5
b. The valve element 5 is urged in a closing direction by a compression spring 8, and the diaphragm 7 is urged in a direction to open the valve element 5 by a pressure adjusting spring 9 and is in contact with the stem 5 b. Although not shown, a pressure adjusting dial is screwed into the upper portion of the valve housing 2, and the secondary pressure is adjusted by rotating the pressure adjusting dial to change the amount of compression of the pressure adjusting spring 9.

[0003] secondary pressure acts on the secondary side pressure receiving surface S ₂ of the spring force F ₁ and the disk 5a of the pressure adjusting spring 9 secondary pressure S ₂
The pressure is set by the composite pressure F ₁ + (S ₂ · p ₂ ) with the pressure P ₂ , the spring force F ₂ of the compression spring 8, the secondary pressure S ₁ · p ₂ acting on the pressure receiving surface S ₁ of the diaphragm 7, and the disc 5a, the combined pressure with the primary pressure S ₃ · p ₁ acting on the primary pressure receiving surface S ₃ = F ₂ + (S ₁ · p ₂ ) + (S ₃ · p ₁ ), and the set pressure = F ₁ + ( S ₂ · p ₂ ) and the valve element 5
Opens and closes to control the secondary pressure.

When the secondary pressure rises above the set pressure,
The diaphragm 7 further rises due to the secondary pressure S ₁ · p ₂ and separates from the stem 5a of the valve body 5, the relief port 7a at the center of the diaphragm 7 is opened, and the secondary-side pressure air is discharged to the atmosphere.

When the primary pressure p ₁ is released, F ₁ + (S ₂ · p ₂ )> F ₂ + (S ₁ · p ₂ ) + (S ₃
(P ₁ ), the valve element 5 is pushed down, the inlet 3 communicates with the outlet 4, and the secondary-side pressure air is discharged from the inlet 3.

This type of direct-acting pressure reducing valve is provided with a primary side receiving valve 5.
Pressure surface S_ThreePrimary pressure S acting on_Three・ P ₁Set pressure according to
Fluctuates and the set pressure rises when the primary pressure drops
Having, for example, between an air compressor and a pneumatic tool
When a direct acting pressure reducing valve is inserted as an air pressure regulator
Air nailing on the secondary side due to a decrease in the primary tank pressure
The firing power of the machine and the tightening torque of the air driver have increased.
In addition, there is a disadvantage that the air consumption increases.

The pressure receiving area S of the diaphragm 7₁Increase
The primary pressure receiving area S of the valve element 5 _ThreeIs relatively reduced
By doing so, the effect of the primary pressure on the secondary pressure can be reduced,
There is a disadvantage that the size of the pressure reducing valve is increased.

FIG. 5 shows a balance type pressure reducing valve 11, and FIG.
Is a valve housing, 13 is a high pressure inlet, and 14 is a pressure reducing outlet. A cylinder portion 12a into which the piston portion 15a of the valve body 15 is inserted is formed at an inner bottom portion of the valve housing 12, and the valve body 15 passes through an axial center from a distal end surface of the piston portion 15a to an upper side surface of the stem 15b. Passage 15c
Is provided. Reference numeral 16 denotes a pilot chamber, 17 denotes a diaphragm, 18 denotes a compression spring, and 19 denotes a pressure adjusting spring.

The upper and lower pressure receiving surfaces S of the valve element 15_TwoAnd S_ThreeThe area of
Secondary pressure S acting on both upper and lower sides equally_Two・ P_TwoAnd S_Three・
p_TwoIs equal pressure, and the outer edge of the disc 15d of the valve body 15
The primary pressure receiving areas of the upper and lower surfaces are almost equal, and the primary pressure p₁of
The effect is negligible. Therefore, the valve element 15 is
Sum of the spring force and the secondary pressure acting on the diaphragm 7 = F _Two
+ (S₁・ P_Two) And the spring force F of the pressure adjusting spring 19₁When
Opening and closing by the balance of the primary pressure p₁Gives the set pressure
Has been eliminated.

The balanced pressure reducing valve 11 is a direct acting pressure reducing valve 1.
Although the pressure control characteristics are better, the valve is opened and closed only by the secondary pressure, so the valve maintains the closed state even if the primary pressure is released when the valve is closed at the secondary pressure = set pressure. , Pressurized air remains on the secondary side. Therefore, for example, when a balanced pressure reducing valve is inserted between the air compressor and the air tool, it is possible to start the air tool even after stopping the air supply on the primary side, which is disadvantageous in terms of safety. .

Therefore, there arises a technical problem to be solved in order to provide a pressure reducing valve having both the safety of a direct acting pressure reducing valve and the stability of pressure control of a balanced pressure reducing valve.
An object of the present invention is to solve the above problems.

[0012]

SUMMARY OF THE INVENTION The present invention proposes to achieve the above-mentioned object, in which a valve element which moves vertically with respect to a valve seat is provided with a spring force of a pressure adjusting spring and a secondary pressure. A pressure reducing valve that is controlled to open and close by a pilot valve that slides in accordance with the pressure difference between the disk, a valve, a stem provided on a surface of the disk facing the valve seat, and a piston connected to the back of the disk. Consisting of
A cylinder provided in the valve housing, wherein the piston portion is formed to have a smaller diameter than the disc and the valve seat so that the primary pressure receiving area on the back side of the disc is larger than the primary pressure receiving area on the outer edge portion of the valve seat facing surface; And a pressure reducing valve provided with a passage for communicating a secondary side air chamber and the cylinder, or a vent communicating from the cylinder to the atmosphere. .

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows a pressure reducing valve 21, 22 is a valve housing, 23 is a high pressure inlet, and 24 is a pressure reducing outlet. The piston portion 25a of the valve body 25 is inserted into a cylinder portion 22a formed at the inner bottom of the valve housing 22, and the upper stem 25b projects into the pilot chamber 26 through the hole 26a of the partition wall of the pilot chamber 26. 2
7 diaphragm 28 is a compression spring of the valve body 25, 29 is a pressure adjusting spring, the spring force F ₂ of the spring force F ₁ and the compression spring of the pressure adjusting spring 29, becoming a relationship of F _1> F ₂ I have. Then, the secondary pressure is adjusted by rotating the pressure adjustment dial (not shown) on the upper part of the valve housing 22 to change the amount of compression of the pressure adjustment spring 29.

As in the case of the conventional balance type pressure reducing valve, the valve body 2
5 is provided with a passage 25c that passes through the axis from the tip end surface to the upper side surface of the stem 25b. Further, the outer diameter of the upper and lower intermediate portion of the disk 25d is substantially equal to the outer diameter of the valve seat 30 with which the disk 25d contacts and separates, so that the primary pressure receiving area of the outer peripheral portion of the upper surface of the disk 25d is made as small as possible. So that the primary pressure hardly acts.

The pressure receiving areas of the secondary pressure receiving surfaces S ₂ and S ₃ on the upper and lower sides of the valve body 25 are equal, and the valve body 25 has a spring force F ₂ of the compression spring 28 and a primary pressure receiving surface of the lower surface of the disk 25 d. S
_The primary pressure S ₄ · p ₁ to ₄ acts as pressure in the closing direction.

The secondary pressure is determined by the spring force F ₁ of the pressure adjusting spring 29.
Is set by a spring force F ₂ of the compression spring 28, the secondary pressure S ₁ · p ₂ to the pressure receiving surface S ₁ of the diaphragm, the primary pressure S ₄ · of the lower surface of disc 25d to the primary pressure receiving surfaces S ₄ p
Combined pressure of ₁ = F ₂ + (S ₁ · p ₂ ) + (S ₄ · p ₁ )
The valve body 25 is opened and closed by the balance between the set pressure = F ₁ and.

When the secondary pressure is lower than the set pressure, F ₁ > F ₂
In the case of + (S ₁ · p ₂ ) + (S ₄ · p ₁ ), the diaphragm 27 is moved by the spring force F ₁ of the pressure adjusting spring 29.
5 is depressed and opened from the closed state shown in FIG. 1, and the primary side pressure air is supplied to the secondary side. The secondary pressure rises and F
_{When 1} <F ₂ + (S ₁ · p ₂ ) + (S ₄ · p ₁ ),
As shown in FIG. 1, the diaphragm 27 rises, the disk 25d contacts the valve seat 30 and closes the passage, and the secondary pressure is controlled to the set pressure.

If the secondary pressure rises above the set pressure,
The diaphragm 27 further rises due to the secondary pressure S ₁ · p ₂ and separates from the stem 25a of the valve body 25, and the diaphragm 2
7, the relief port 27a is opened, and the secondary side pressure air is discharged to the atmosphere.

Further, when the secondary pressure is equal to the set pressure, F ₁ = F ₂ + (S
When _{1 · p 2) + (S} 4 · p 1) valve body 25 is balanced by releases the primary pressure p ₁ from a state in which the closed, primary pressure S ₄ · p to the pressure receiving surface S ₄ of the disk 25d ₁ becomes zero and F ₁ > F ₂ + (S ₁ · p ₂ ) + (S ₄ · p ₁ ). As in the case of the decrease in the secondary pressure, the diaphragm is adjusted by the spring force F ₁ of the pressure adjusting spring 29. 27 pushes down the valve body 25, and the inlet 23 and the outlet 24 communicate with each other, and the secondary-side compressed air is discharged from the high-pressure inlet.

FIG. 2 shows another embodiment.
The first valve body 32 has a piston portion 32a similarly to the valve body of FIG.
, The stem 32b and the disk 32c, but there is no passage through the axis, and the valve housing 33
A vent 33b is provided in the cylinder portion 33a of the
Not to brake the movement.

The secondary pressure is controlled by a pressure adjusting valve of the diaphragm 34.
The spring force F of the spring 35₁And the secondary pressure receiving surface S of the valve body 32_TwoWhat
Secondary pressure S_Two・ P_TwoSum F₁+ (S_Two・ P_TwoBy)
The spring force F of the compression spring 36 is set._TwoAnd the diaphragm
34 pressure receiving surface S₁Secondary pressure S to₁・ P_TwoAnd disk 32
Primary pressure receiving surface S under d_ThreePrimary pressure S to_Three・ P₁If
Formation pressure = F_Two+ (S₁・ P_Two) + (S_Three・ P₁)
Constant pressure = F₁+ (S_Two・ P_Two) And valve by balance
The body 25 opens and closes. This pressure reducing valve 31 is also the pressure reducing valve 2 of FIG.
1, the primary pressure receiving surface S of the disk 32c. _ThreeArea
Change in the secondary pressure due to the influence of the primary pressure.
Movement is suppressed.

Then, the secondary pressure becomes the set pressure and the valve element 32
When but releasing the primary pressure p ₁ from a state in which the closed primary pressure S acting to the primary pressure receiving surfaces S ₃ disk 25d
₃ · p ₁ decreases, and F ₁ + (S ₂ · p ₂ )> F ₂ + (S
₁ · p ₂ ) + (S ₃ · p ₁ ), the valve body 32 is lowered as in the case of a decrease in the secondary pressure, the inlet 37 communicates with the outlet 38, and the secondary-side pressure air is discharged from the inlet 37. You.

The present invention is not limited to the above embodiment, and various modifications are possible within the technical scope of the present invention, and it is natural that the present invention extends to those modifications. is there.

[0024]

FIG. 3 is a graph showing the test results of the pressure characteristics of the pressure reducing valve 21 having the structure shown in FIG. In the figure, as shown by the solid line, the pressure reducing valve 21 has a primary pressure of 4 kgf / cm ^{2 to} 8 kgf / cm ^2.
2 range, the maximum fluctuation range of set pressure ^{(5kgf / cm 2, 4kgf /} cm 2) is about 0.1 kgf / cm ^2, the maximum fluctuation width of about 0 to conventional linear-type pressure reducing valve 1 shown by a broken line The characteristic is extremely smaller than .49 kgf / cm ² and is close to that of the balance type pressure reducing valve 11.

[0025]

As described above, the pressure reducing valve of the present invention has a small influence on the secondary pressure due to the fluctuation of the primary pressure, has a pressure control characteristic comparable to that of a balanced pressure reducing valve, and has a primary pressure Is released, the valve is opened as in the case of the direct acting pressure reducing valve, and the secondary side pressure air is discharged. Therefore, in applications such as pressure adjustment of the pneumatic tool, it becomes impossible to start the pneumatic tool after the supply of air on the primary side is stopped, so that safety can be ensured and the inconvenience of the conventional pressure reducing valve can be solved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a pressure reducing valve, showing an embodiment of the present invention.

FIG. 2 shows another embodiment of the present invention and is a cross-sectional view of a pressure reducing valve.

FIG. 3 is a pressure characteristic graph of the pressure reducing valve of FIG. 1;

FIG. 4 is a cross-sectional view of a direct acting pressure reducing valve, showing a conventional example.

FIG. 5 is a cross-sectional view of a balanced pressure reducing valve, showing a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 21 Pressure reducing valve 22 Valve housing 22a Cylinder part 23 High pressure inlet 24 Pressure reducing outlet 25 Valve 25a Piston part 25b Stem 25c Passage 25d Disk 26 Pilot chamber 27 Diaphragm 28 Compression spring 29 Pressure adjustment spring 30 Valve seat

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Kihara Yanghara 6-6 Nihonbashi Hakozakicho, Chuo-ku, Tokyo Max. Inside the corporation

Claims (1)

[Claims] 1. A pressure reducing valve that controls opening and closing of a valve body that moves in a direction perpendicular to a valve seat by a pilot valve that slides according to a differential pressure between a spring force of a pressure adjusting spring and a secondary pressure, The valve body is composed of a disk, a stem provided on the valve seat-facing surface of the disk, and a piston connected to the back of the disk.The piston is formed to have a smaller diameter than the disk and the valve seat. The back pressure side primary pressure receiving area of the disc is set to be larger than the primary pressure receiving area of the outer peripheral portion of the valve seat facing surface, and the distal end portion of the piston portion is inserted into a cylinder portion provided in the valve housing, and the secondary side air chamber and A pressure reducing valve provided with a passage communicating with the cylinder part or a vent communicating with the atmosphere from the cylinder part.