JPH0539204Y2 - - Google Patents

Description

[Detailed description of the invention] (Industrial application field) This invention is an accumulator used as a pressure control device such as a shock absorber for an automobile, a fuel system of a large boiler, a counter balancer of a machine tool, etc. The present invention relates to a piston-type accumulator that includes a piston that reciprocates in response to the pressure of a pressure-varying fluid.

(Prior Art) FIG. 2 shows a front sectional view of a conventional piston type accumulator A. In the figure, 100 is a hollow cylindrical accumulator body with a bottom.
On the open end surface of this accumulator main body 100,
An end plate 102 having an inflow path 101 for pressure fluctuating fluid is fixed. In addition, in the accumulator main body 100, the accumulator main body 10
A piston 104 is loaded in contact with the inner circumferential surface 103 of 0. Note that O-rings 105 and 106 as movement seals are attached to the contact surface E between the piston 104 and the accumulator main body 100.

In this manner, the inside of the accumulator main body 100 is divided into a variable pressure chamber 107 into which a pressure fluctuating fluid is introduced through the inflow path 101 and a constant pressure chamber 109 into which compressed gas at a predetermined pressure is filled through the injection hole 108.

In the piston type accumulator A configured as described above, a pressure fluctuating fluid such as hydraulic oil is introduced into the variable pressure chamber 107 via the inflow path 101 by a fluid pressure generating device such as a pump (not shown). At this time, when the pressure in the variable pressure chamber 107 becomes higher than the pressure in the constant pressure chamber 109, the piston 104 operates in the direction of arrow B, and the pressure in the variable pressure chamber 107 increases to the constant pressure chamber 109.
When the pressure becomes lower than the pressure inside 9, it operates in the direction of arrow D. In this way, the pressure accumulation function is achieved, and the inflow path 1
Controlled part (not shown) communicating with the outside of 01
The pressure is controlled.

During the above operation, the O-rings 105 and 106 allow the compressed gas in the constant pressure chamber 109 to
0 and the piston 104 from entering into the variable pressure chamber 107 through the contact surface E between the piston 104 and the piston 104.

(Problem to be solved by the invention) However, in the above conventional example, when the pressure in the variable pressure chamber 107 becomes lower than the pressure in the constant pressure chamber 109, the constant pressure Due to the pressure difference, the compressed gas in the chamber 109 would enter the pressure-changing chamber 107 through the contact surface E, thereby impairing the pressure accumulating function.

Furthermore, the O-rings 105 and 106 are easily deformed due to the load due to pressure fluctuations within the variable pressure chamber 107, leading to a decrease in sealing performance due to wear, further aggravating the above-mentioned problems.

This idea is to solve the above problem,
To provide a piston type accumulator that can prevent compressed gas in the constant pressure chamber from entering the variable pressure chamber through the contact surface between the piston and the accumulator body when the pressure in the variable pressure chamber becomes lower than the pressure in the constant pressure chamber. It is an object.

Another purpose is to prevent the dynamic seal attached to the piston from being deformed and worn out due to the load (pressure) from the constant pressure chamber side as the pressure in the variable pressure chamber decreases.

(Means for Solving the Problems) In order to achieve the above object, this invention has a piston slidably mounted inside the accumulator body formed in the hollow, so that a pressure fluctuating fluid is introduced into the accumulator body. The chamber is divided into a variable pressure chamber filled with compressed gas at a predetermined pressure, and a constant pressure chamber filled with compressed gas at a predetermined pressure, and a dynamic seal is installed on the outer periphery of the piston to seal between the sliding surfaces between the inner periphery of the accumulator body and the outer periphery of the piston. In the piston-type accumulator, the moving seals are installed at at least two places on the constant pressure chamber side and the variable pressure chamber side, spaced apart by a predetermined distance, and the moving seals are installed on the outer periphery of the piston between the moving seals on the constant pressure chamber side and the variable pressure chamber side. In addition, a high pressure chamber is provided, which is filled with a fluid having a pressure slightly higher than that of the compressed gas in the constant pressure chamber.

(Function) The function of this invention based on the above configuration is that the piston reciprocates within the accumulator body in response to pressure fluctuations within the variable pressure chamber. The contact surface between the accumulator body and the piston is sealed by a dynamic seal. The high pressure chamber, which is the contact surface between the accumulator body and the piston and is located between the variable pressure chamber and the constant pressure chamber, is filled with a fluid with a pressure slightly higher than that of the compressed gas in the constant pressure chamber. Gas is blocked by the high pressure chamber and does not leak to the variable pressure chamber side.

(Example) Next, this invention will be explained based on the example shown in FIG.

In the figure, 1 is a piston type accumulator to which the present invention is applied. The shell 2 serving as the main body of the accumulator has a hollow cylindrical shape with a bottom, and an end plate 4 having an inlet passage 3 through which a pressure varying fluid such as hydraulic oil flows is fixed to the open end surface of the shell 2 . A threaded portion 5 is formed on the outer end surface of the end plate 4 so that it can be screwed onto various types of equipment. Moreover, the outside side of the inflow path 3 is
It is connected to a line (not shown) that connects a fluid pressure generating device such as a pump (not shown) and a controlled section.
Note that 6 is an O-ring attached to the outer end surface of the end plate 4.

A piston 7 is loaded in the shell 2 so as to be able to reciprocate in a predetermined direction, and the piston 7 has a generally H-shaped cross section with a large diameter portion 7b facing each other with a small diameter portion 7a in between. The large diameter portion 7b forms a contact surface 9 as a sliding surface that slidably contacts the inner circumferential surface 8 of the shell 2. Further, an O-ring 10 as a dynamic seal is attached to the outer periphery of the large diameter portion 7b, and is in close contact with the inner circumferential surface 8 of the shell 2.
This piston 7 divides the interior of the shell 2 into a variable pressure chamber 12 into which a pressure fluctuating fluid is introduced, and a constant pressure chamber 14 into which compressed gas is sealed via an injection hole 13.

Reference numeral 11 denotes a piston 7, which is a high pressure chamber formed between the contact surface 9 with the accumulator main body 2, that is, between the large diameter portions 7b. A fluid with a pressure slightly higher than that of gas, such as oil, is sealed. In order to seal the fluid into the high pressure chamber 11, for example, an injection hole (not shown) for high pressure fluid is provided in the large diameter portion 7b on the end plate 4 side, penetrating from the high pressure chamber 11 to the variable pressure chamber 12 side. This may be carried out by sealing high-pressure fluid through the injection hole from the inflow path 3 side by appropriate means and then closing the injection hole. In this case, if a check valve is provided in the injection hole, the workability of sealing the high-pressure fluid is improved.

15 is a gas plug screwed into the injection hole 13 in the bottom 16 of the shell 2, and 17 is an O-ring.

Next, the operation of the above embodiment will be explained.

First, pressure fluctuating fluid such as hydraulic oil supplied from a fluid pressure generating device (not shown) flows into the variable pressure chamber 12 via the inflow path 3 . And the transformation room 12
When the pressure inside the variable pressure chamber 12 is higher than the pressure inside the constant pressure chamber 14, the piston 7 operates in the direction of the arrow F to accumulate pressure, and when the pressure inside the variable pressure chamber 12 becomes lower than the pressure inside the constant pressure chamber 14, the piston 7 moves in the direction of the arrow G. It operates. In this way, pressure control to the controlled portion is performed.

During the above operation, the O mounted on the piston 7
The ring 10 seals the contact surface 9 between the piston 7 and the shell 2. Further, a fluid having a pressure slightly higher than the compressed gas in the constant pressure chamber 14 is sealed in the high pressure chamber 11 . Therefore, when the pressure in the variable pressure chamber 12 becomes lower than the pressure in the constant pressure chamber 14, the compressed gas in the constant pressure chamber 14 that attempts to enter the contact surface 9 is pushed back by the fluid in the high pressure chamber 11. Therefore, even if the fluid in the high pressure chamber 11 reaches the constant pressure chamber 14 through the contact surface 9, the constant pressure chamber 14
The compressed gas inside will not intrude into the variable pressure chamber 12 side through the contact surface 9. Therefore, a stable pressure accumulation function and a pressure control function for the controlled portion can be always exhibited.

Furthermore, even if the pressure in the variable pressure chamber 12 drops significantly compared to the pressure in the constant pressure chamber 14, the pressure in the high pressure chamber 11 is maintained at a slightly higher level than that in the constant pressure chamber 14, so there is no difference in the pressure. There is almost no pressure,
Depending on the load (pressure) on the constant pressure chamber 14 side, the O-ring 1
0 will not be deformed or worn out. Therefore, the durability of the O-ring 10 is improved, and stable sealing performance can be exhibited over a long period of time.

(Effect of the device) Since this device is configured as described above, even if the pressure in the variable pressure chamber becomes lower than the pressure in the constant pressure chamber, the compressed gas in the constant pressure chamber is pressed by the fluid in the high pressure chamber. Therefore, the compressed gas in the constant pressure chamber does not enter the variable pressure chamber through the contact surface between the accumulator main body and the piston. Therefore, a stable pressure accumulation function and a pressure control function for the controlled portion can be always exhibited.

In addition, even if the pressure in the variable pressure chamber is significantly lower than the pressure in the constant pressure chamber, the pressure difference between the high pressure chamber and the constant pressure chamber is maintained constant, so the dynamic seal facing the constant pressure chamber is No excessive load (pressure) is applied from the constant pressure chamber side, and the dynamic seal will not be deformed or worn out. Therefore, the durability of the sports seal is improved, and various excellent effects are achieved, such as being able to exhibit stable sealing performance over a long period of time.

[Brief explanation of the drawing]

FIG. 1 is a front sectional view showing an embodiment of the present invention, and FIG. 2 is a front sectional view showing a conventional example. Explanation of symbols: 1... piston type accumulator, 2... shell (accumulator body), 7...
...piston, 9...contact surface, 10...O-ring (dynamic seal), 12...variable pressure chamber, 14...constant pressure chamber.

Claims (1)

[Claims for Utility Model Registration] By slidably mounting a piston inside the hollow-molded accumulator main body, a variable pressure chamber into which a pressure fluctuating fluid is introduced and a compressed gas at a predetermined pressure are created within the accumulator main body. In a piston-type accumulator, the piston-type accumulator is divided into a constant pressure chamber to be enclosed, and a movement seal is attached to the outer periphery of the piston for sealing a gap between a sliding surface between the inner periphery of the accumulator main body and the outer periphery of the piston. The pressure of the compressed gas in the constant pressure chamber is installed between the motion seals on the constant pressure chamber side and the variable pressure chamber side on the outer periphery of the piston. A piston-type accumulator characterized by being provided with a high-pressure chamber in which a fluid at a higher pressure than the above chamber is sealed.