JP3382984B2 - Relief valve - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to, for example, a relief valve incorporated in a hydraulic circuit, and more particularly to a device devised to suppress generation of surge pressure at the time of rising of a pressure port side.

[0002]

2. Description of the Related Art A conventional relief valve incorporated in a hydraulic circuit has, for example, a structure shown in FIG.
First, there is a housing 101, and this housing 101
Pressure ports P1 and P2 are formed in each of them.
With space 103 to contact the pressure ports P1, P2 are formed in the housing 101, the air
The open end of the intermediate portion 103 is closed by an end plug 105. A member 107 having a substantially hollow shape is provided inside the space 103 on the right side of the drawing, and a poppet sheet 107a is formed at the left end of the member 107 in the drawing.

A sleeve 109 is provided inside the hollow portion 103 at a position on the left side of the drawing. The right end portion of the sleeve 109 in the figure is externally fitted to the outer peripheral portion of the member 107. A piston 111 is installed on the outer circumference of the sleeve 109 so as to be movable in the left-right direction in the drawing.
A poppet 113 is arranged in the sleeve 109 so as to be movable in the left-right direction in the drawing. The poppet 113 is biased rightward in the figure by a coil spring 117 mounted on the left side in the figure via a member 115, and the tip end thereof is in contact with the poppet sheet 107a.

The poppet 113 has a passage 1 at an axial center position.
19 is formed, and an orifice 121 is formed in the middle of the passage 119. Also, the member 115
A through hole 123 is formed in the. Incidentally, reference numeral 12 in the drawing
Reference numerals 5 and 127 respectively denote seal rings.

According to the above configuration, first, the pressure port P1
When the side is low pressure and the pressure port P2 side is high pressure, the state is as shown in the figure. That is, the poppet 113 is pressed against the poppet seat 107a side by the spring force of the coil spring 117 and the pressure from the pressure port P2 side. In that state,
When the pressure port P1 side becomes high pressure and the pressure port P2 side becomes low pressure, it changes as follows. First, the hydraulic oil on the pressure port P1 side is supplied to the orifice 121 and the passage 11
9, through the through hole 123, flows to the side of the spring chamber 129 where the coil spring 117 is mounted.
The hydraulic oil flows through the hole 131 formed in the sleeve 109 into the chamber 133 on the left side of the piston 111 in the drawing. As a result, the piston 111 is pushed rightward in the figure.

Further, since a differential pressure is generated before and after the orifice 121, the poppet 113 has a coil spring 117.
It moves to the left side in the figure against the spring force of. As a result, the poppet sheet 107a is opened, and a passage having a predetermined opening is formed between the pressure port P1 and the pressure port P2 side.

[0007]

The above-described structure has the following problems. That is, in the case of the relief valve having the above configuration, there is a problem that the generation of surge pressure cannot be effectively suppressed. That is, the piston 11
1 starts to move, the pressure on the pressure P1 port side once rises to a predetermined pressure, and thereafter, while the piston 111 moves, the pressure is substantially maintained. If it collides with, surge pressure will be generated thereafter.

The present invention has been made on the basis of the above points, and an object of the present invention is to provide a relief valve capable of preventing the occurrence of surge pressure as described above without complicating the structure. To provide.

[0009]

In order to achieve the above object, a relief valve according to the present invention comprises a housing having a pressure port P1 and a pressure port P2, and a back piston movably accommodated in the housing. The back end is movably accommodated in the housing and the base end thereof is the back fixer.
A poppet that is fitted around the outer circumference of the poppet and the tip of which comes in and out of contact with the poppet seat, a coil spring installed between the back piston and the poppet, and a free mover provided on the outer circumference of the poppet. A first hole communicating with the piston, the pressure port P1 side provided in the poppet and the spring chamber in which the coil spring is installed, the spring chamber formed in the back piston and the opposite spring chamber side of the back piston. And a third hole for communicating the spring chamber provided in the poppet with the back pressure chamber on the side opposite to the back piston of the free piston, and a predetermined amount of movement of the free piston toward the back piston. second stopper for regulating a first stopper for restricting the movement of the free piston side of the back piston to a predetermined amount Comprising a, the pressure port P1 side high
When the pressure shifts to the pressure, the hydraulic oil on the pressure port P1 side becomes the first
Flow into the back pressure chamber of the free piston through the hole and the third hole
The free piston collides with the first stopper
Hydraulic fluid on the pressure port P1 side is the first
Anti-Spring of back spring through hole and second hole
The back piston sprinkles as it flows into the chamber.
It is characterized by moving to the poppet side against the drag .

It is also conceivable to form a fourth hole in the free piston so as to communicate with both sides in the axial direction. It is also conceivable to install a coil spring between at least one of the free piston and the first stopper and between the back piston and the second stopper. It is also conceivable to form a fifth hole in the back piston that connects the side opposite to the spring chamber of the back piston and the side of the free piston.
It is also conceivable to form a collar portion on the poppet and form a sixth hole communicating with both sides in the axial direction on the collar portion.

[0011]

In the case of the present invention, the free piston is moved and the back piston is moved so as to suppress the generation of surge pressure. That is, initially, the movement of the free piston suppresses the generation of surge pressure, and the movement of the back piston adjusts the position of the poppet.
It suppresses the generation of surge pressure. The adjustment range can be adjusted by appropriately setting the diameters of the first to third holes and the positions of the first and second stoppers.
In addition to the above, by implementing the means described in claims 2 to 5, the adjustment range can be expanded.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The first embodiment of the present invention will be described with reference to FIGS.
An example will be described. First, there is a housing 1, and pressure ports P1 and P2 are formed in the housing 1, respectively. A hollow portion 3 is formed in the housing 1, and the left end of the hollow portion 3 in the figure is closed by an end plug 5. A back piston 7 is installed in the hollow portion 3 at the upper end in the figure. This back piston 7
A hole 7a (second hole) is formed at the axial center position of.
Further, a poppet 9 is installed below the back piston 7 in the figure so as to be movable in the vertical direction in the figure. This poppet 9
The upper end portion in the figure is fitted onto the outer circumference of the back piston 7.

A coil spring 11 is provided between the back piston 7 and the poppet 9, and the poppet 9 is urged downward by the coil spring 11 in the figure. In addition, the poppet 9 has a hole (first hole) 13
And the hole 15 (third hole) is formed. A free piston 17 is housed on the outer periphery of the poppet 9 so as to be vertically movable in the figure.
The tip of the poppet 9 is in contact with the poppet sheet 19. Reference numeral 21 in the figure is a seal ring.

The operation will be described based on the above configuration. First, when the pressure port P2 side is high pressure and the pressure port P1 side is low pressure, the state is as shown in FIGS. In this state, when the pressure port P1 side is high pressure and the pressure port P2 side is low pressure, the following changes occur. That is, the hydraulic oil on the pressure port P1 side is
It flows into the back pressure chamber 23 on the lower side of the free piston 17 in the figure through the hole 15. Thereby, free piston 1
7 moves upward in the drawing until it collides with the stopper 25. At this time, the pressure on the pressure port P1 side is
As shown in FIG. 3, after rising to P11, the state is maintained (area of Δt1 in FIG. 3).

On the other hand, the hydraulic oil on the pressure port P1 side is
3, it also flows into the chamber 27 on the upper side of the back piston 7 in the figure through the spring chamber and the hole 7a, and as a result, the back piston 7 moves downward in the figure. By moving the back piston 7 downward in the figure, the coil spring 11
Is being compressed, the set load will increase.
As a result, the pressure rise on the pressure port P1 side is suppressed, and as shown in FIG. 3, the pressure on the pressure port P1 side gradually rises to reach P12 (area Δt2 in FIG. 3).
That is, it is possible to suppress the generation of surge pressure as indicated by the broken line in FIG.

Further, P11 and P1 in the characteristic diagram shown in FIG.
Regarding 2, Δt1 and Δt2, these can be adjusted appropriately. That is, Δt1 can be adjusted by appropriately adjusting the diameters of the holes 13 and 15 and the stroke until the free piston 17 collides with the stopper 25. Further, by adjusting the diameters of the holes 13 and 7a, the stroke until the back piston 7 collides with the stopper 29, the initial deflection of the coil spring 11 and the spring constant,
11 and P12 and Δt2 can be adjusted. That is,
It is possible to easily deal with various specifications required by the hydraulic circuit to which the invention is applied. Moreover, its configuration is extremely simple.

Next, a second embodiment will be described with reference to FIG. In the case of this embodiment, the free piston 17 is further formed with another hole (fourth hole) 31 extended in the axial direction. That is, as described above, the moving speed of the free piston 17 can be adjusted by appropriately adjusting the diameters of the holes 13 and 15 and the stroke until the free piston 17 collides with the stopper 25. By doing so, the adjustment range is further expanded.

Next, a third embodiment will be described with reference to FIG. In the case of this embodiment, in the structure of the first embodiment, the coil spring 33 is provided between the free piston 17 and the stopper 25, and the back piston 7
The coil spring 35 is provided between the stopper 29 and the stopper 29. In this case, the coil spring 33 increases as an element for adjusting Δt1, and the coil spring 35 increases as an element for adjusting Δt2, so that the adjustment range can be expanded.

Next, a fourth embodiment will be described with reference to FIG. In the case of this embodiment, in the structure according to the second embodiment, a hole (fifth hole) extended axially in the back piston is provided.
37 is formed. In this case, the number of the holes 37 is increased as an element for adjusting Δt2, and in this case as well, the adjustment range can be expanded.

Next, a fifth embodiment will be described with reference to FIG. In the case of this embodiment, the adjusting means 39 for adjusting the initial set load of the coil spring 11 is provided in the configuration shown in the first embodiment. The adjusting means 39 includes an adjusting screw 41 and the adjusting screw 41.
And a moving member 43 interposed between the back piston 7 and the back piston 7. The initial set load of the coil spring 11 is adjusted by rotating the adjusting screw 41 in an appropriate direction. With this configuration, P11, P12, Δt1 and Δt2 can be adjusted.

Next, a sixth embodiment will be described with reference to FIG. In the case of this embodiment, in the structure shown in the first embodiment, the collar portion 45 is formed on the poppet 9 and
A hole (sixth hole) 47 extending in the axial direction is formed in the collar portion 45. In this case, the free piston 1
When the 7 moves, a differential pressure is generated before and after the hole 47, so that the poppet 9 can be moved more quickly. Thereby, generation of surge pressure can be suppressed more effectively.

Next, a seventh embodiment will be described with reference to FIG. In this embodiment, the structure of the sixth embodiment is applied to the structure of the second embodiment, that is, the collar portion 45 and the hole 47 are applied. Therefore, the same effect as that of the sixth embodiment can be obtained. Can play. Further, an eighth embodiment shown in FIG. 10 is one in which the collar portion 45 and the hole 47 are applied to the structure of the third embodiment, and therefore, the same as in the case of the sixth embodiment and the seventh embodiment. The effect of can be produced. Moreover, FIG.
In the case of the ninth embodiment shown in FIG. 1, the collar portion 45 and the hole 47 are applied in the configuration of the fourth embodiment, and therefore, the sixth embodiment, the seventh embodiment and the eighth embodiment. The same effect as that of the example can be obtained. Furthermore, FIG.
In the case of the tenth embodiment shown in FIG. 2, the collar portion 45 and the hole 47 are applied in the configuration of the fifth embodiment,
Therefore, the same effects as in the case of the sixth embodiment, the seventh embodiment, the eighth embodiment, and the ninth embodiment can be obtained.

[0023]

As described in detail above, according to the relief valve of the present invention, the free piston is moved and
Since the back piston is configured to move, the generation of surge pressure can be suppressed more effectively. Further, by appropriately setting the diameters of the first to third holes and the positions of the first and second stoppers, the method according to claim 2
By implementing the means according to claim 5, the characteristics can be appropriately set according to the specifications of the hydraulic circuit to be applied, and the hydraulic circuit according to a wide range of specifications can be dealt with.

[Brief description of drawings]

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

FIG. 2 is a sectional view showing a first embodiment of the present invention in an enlarged manner and showing a main part of FIG.

FIG. 3 is a view showing a first embodiment of the present invention and is a pressure port P1.
It is a characteristic view which shows the pressure change of the side.

FIG. 4 is a cross-sectional view of a relief valve according to a second embodiment of the present invention.

FIG. 5 is a cross-sectional view of a relief valve according to a third embodiment of the present invention.

FIG. 6 is a sectional view of a relief valve according to a fourth embodiment of the present invention.

FIG. 7 is a sectional view of a relief valve according to a fifth embodiment of the present invention.

FIG. 8 is a sectional view of a relief valve according to a sixth embodiment of the present invention.

FIG. 9 is a cross-sectional view of a relief valve showing the seventh embodiment of the present invention.

FIG. 10 is a sectional view of a relief valve according to an eighth embodiment of the present invention.

FIG. 11 is a sectional view of a relief valve according to a ninth embodiment of the present invention.

FIG. 12 is a cross-sectional view of a relief valve according to a tenth embodiment of the present invention.

FIG. 13 is a cross-sectional view of a relief valve showing a conventional example.

[Explanation of symbols]

1 housing 7 back piston 7a hole (2nd hole) 9 poppets 11 coil spring 13 holes (first hole) 15 holes (3rd hole) 17 Free piston 19 poppet sheet

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-1-176870 (JP, A) Actually opened 64-14971 (JP, U) Actually opened 63-97768 (JP, U) Actually opened 58- 33834 (JP, U) Actual development 57-100675 (JP, U) Actual development 50-44329 (JP, U) Actual development 62-162477 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) F16K 17/00-17/168

Claims (5)

(57) [Claims] 1. A housing having a pressure port P1 and a pressure port P2, a back piston movably accommodated in the housing, and a base end movably accommodated in the housing, the base end of which is the back piston. External fitting on the outer circumference
Between the back piston and the poppet and the poppet whose tip is separated from and in contact with the poppet sheet.
A coil spring which is furnished to the first hole that communicates with the free piston which is movable in the outer periphery, and a spring chamber that the pressure port P1 side provided in the poppet and the coil spring is disposed in the poppet When,
A second hole formed in the back piston for communicating the spring chamber with the side opposite to the spring chamber of the back piston;
A third hole provided in the poppet for communicating the spring chamber with the back pressure chamber on the side opposite to the back piston of the free piston;
A first stopper for restricting the movement of the free piston to the back piston side to a predetermined amount and a second stopper for restricting the movement of the back piston to the free piston side to a predetermined amount are provided, and the pressure port P1 side has a high pressure. When you move to
The hydraulic oil on the pressure port P1 side is the first hole and the third hole.
By flowing into the back pressure chamber of the free piston via
Move until the free piston collides with the first stopper
Hydraulic oil on the pressure port P1 side, then the first and second holes
Flows into the anti-spring chamber of the back spring through
As a result, the back piston resists the spring and popes.
Relief valve that moves to the shut side . 2. The relief valve according to claim 1, wherein the free piston is formed with a fourth hole communicating with both sides in the axial direction. 3. The relief valve according to claim 1, wherein a coil spring is installed between at least one of the free piston and the first stopper and between the back piston and the second stopper. Relief valve to do. 4. The relief valve according to claim 1, 2 or 3, wherein the back piston is formed with a fifth hole that communicates between the side of the back piston opposite the spring chamber and the side of the free piston. Relief valve to do. 5. The relief valve according to claim 1, 2, 3 or 4, wherein the poppet is provided with a collar portion.
And form a sixth hole communicating with both sides of the collar in the axial direction.
Relief valve characterized by doing