JPH058503Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] This invention relates to a hydraulic pressure detection device, and in particular, a bladder that separates a gas chamber from an oil chamber is displaced in accordance with the hydraulic pressure applied to the oil chamber. This invention relates to a hydraulic pressure detection device installed in an accumulator.

[Prior art]

Generally, in hydraulic equipment, hydraulic pressure is used as a signal source to control the on/off of a hydraulic pump, and a pressure switch is used that switches an electric switch depending on whether the hydraulic pressure is above a specified value. .

Further, in hydraulic equipment, an accumulator as shown in FIGS. 3 and 4 is generally used. In this type of accumulator 21, the interior space of a substantially spherical shell 22 is separated into a gas chamber 25 and an oil chamber 26 by a bladder 24 made of a rubber-like elastic material and fixed to the shell 22 via a holder 23. The gas chamber 25 is filled with an appropriate high-pressure gas, while oil pressure is applied to the oil chamber 26 from an external hydraulic system (not shown) through an oil port 27 fixed to the center of the lower part of the shell 22.
The bladder 24 divides the inside of the shell 22 into approximately two equal parts as shown in FIG. 3 when the gas pressure in the cylinder 5 and the oil pressure applied to the oil chamber 26 are balanced. 28 is a poppet fixed to the center of the bottom surface of the bladder 24, and 30 is an O-ring 2 for sealing.
This is a gas plug fixed to the upper center of the accumulator 21 via the gas plug 9. When the gas chamber 25 is filled with high-pressure gas and no oil pressure is applied to the oil chamber 26, as shown in FIG. It is stuck on the .

[Problem that the invention attempts to solve]

However, for example, it can withstand hydraulic pressure of several hundred Kg/ ^cm2 , and even under this pressure, it can withstand several +Kg/ ^cm2 (20 to 30Kg/cm2).
Pressure switches that detect changes in oil pressure (cm ² ) are limited to Bourdon tube type pressure switches, which are very expensive because they must be assembled with high precision. etc., its useful life (usually about 10 years)
Due to the number of operations during that time, a considerable change in time is unavoidable, resulting in problems such as insufficient accuracy.

Furthermore, if there are initial variations such as variations in the volume of the shell 22, variations in the pressure of the gas initially sealed in the gas chamber 25, and variations in the oil pressure of the system used, the accumulator 21 will be unable to move the operating center of the bladder 24. is not constant, and when used for a long period of time, the high pressure gas in the gas chamber 25 permeates and leaks through the rubber layer of the bladder 24 and the O-ring 29, causing the operating center position of the bladder 24 to be offset toward the gas chamber 25 side. Accumulator 2
The position of No. 1 bladder 24 cannot quantitatively represent the hydraulic pressure itself.

This invention solves the problems of the conventional ones as mentioned above, and ^is low-cost, unaffected by changes in diameter, and capable of increasing the number +
The object of the present invention is to provide a hydraulic pressure detection device capable of detecting hydraulic pressure changes of Kg/cm ² .

[Means for solving problems]

This idea aims to achieve the above objectives.
an accumulator in which a bladder that isolates a gas chamber and an oil chamber is displaced in response to changes in oil pressure applied to the oil chamber, and a rod member that displaces in the longitudinal direction following the displacement of the bladder;
a ring member that is fitted to the rod member and that slides relatively when the rod member is displaced by a predetermined amount or more to allow excessive displacement of the rod member;
The ring member is provided with a member that detects the displacement of the ring member due to the normal displacement of the rod member from the outside in a non-contact manner.

[Effect]

By adopting the above-mentioned means, this device detects a change in the oil pressure applied to the oil chamber of the accumulator as a displacement of the ring member via the bladder and the rod member. Since the normal displacement of the rod member is followed while allowing displacement, changes in oil pressure can be detected without being affected by changes over time.

〔Example〕

Embodiments of this invention shown in the drawings will be described below.

1 and 2 show an embodiment of the oil pressure detection device according to this invention, and this oil pressure detection device is provided in the accumulator 1. As shown in FIG. In the accumulator 1, the internal space of a substantially spherical shell 2 is separated into a gas chamber 5 and an oil chamber 6 by a bladder 4 made of a rubber-like elastic material fixed to the shell 2 via a holder 3. is filled with high-pressure gas such as nitrogen gas, while oil pressure is applied to the oil chamber 6 from an external hydraulic system (not shown) through an oil port 7 fixed to the center of the lower part of the shell 2. When the gas pressure and the hydraulic pressure applied to the oil chamber 6 are balanced, the bladder 4 divides the inside of the shell 2 into approximately two equal parts as shown in FIG. 8 is a poppet fixed to the center of the lower surface of the bladder 4. A case 10 made of a non-magnetic material is fixed to the center of the upper part of the accumulator 1 configured in this way through an O-ring 9 for sealing.
the rod member 11 protruding from the rod member 11;
Spring 1 that presses the lower end of the spring 1 to the center of the top surface of the bladder 4
2, and a ring member 1 fitted to the rod member 11
A bush 14 made of a non-magnetic material is press-fitted into the lower part of the case 10, while a proximity switch such as a reed switch that can detect the vertical movement of the ring member 13 without contact is mounted outside the case 10. 15 are arranged.

As shown in FIG. 2, the upper part of the rod member 11 is formed with an enlarged part 16 to which the spring 12 is engaged.
Further, the ring member 13 has an elastic ring 18 made of an elastic material disposed in an inner circumferential groove of a detection ring 17 made of a ferromagnetic material.
The elastic ring 1 is loosely fitted into the rod member 11.
8 is in close contact with the outer periphery of the rod member 11, and the bush 14 is in close contact with the stepped portion 1 formed inside the case 10.
The range of movement of the ring member 13 is restricted between the ring member 9 and the ring member 9. Therefore, the rod member 11 is
It is possible to descend to a maximum height where the ring member 13 is held between the enlarged portion 16 and the bush 14, and when rising while compressing the spring 12, until the ring member 13 reaches the stepped portion 19. The detection ring 17 rises with the ring member 13, but after the upper surface of the detection ring 17 contacts the stepped portion 19, it slides against the elastic ring 18, so that it can rise without the ring member 13. On the other hand, even when descending, the ring member 13 descends with the ring member 13 until it reaches the bush 14, but after the lower surface of the detection ring 17 contacts the bush 14, the elastic ring 18 By sliding against the ring member 13, the ring member 13 can be lowered without being accompanied by the ring member 13. Therefore, oil chamber 6
The stroke of the rod member 11, which displaces up and down based on the displacement of the plug 4 when the oil pressure applied to it causes a change to be detected, is controlled by the step part 19 and the bush 1.
4, the position of the bladder 4 when the gas pressure in the gas chamber 5 and the oil pressure applied to the oil chamber 6 are balanced will not change over time or otherwise. Even if a vertical shift occurs due to a cause, a predetermined oil pressure change can be detected using the shifted position as a reference.

Next, the operation of the above will be explained.

First, when high-pressure gas is sealed in the gas chamber 5 and hydraulic pressure is applied to the oil chamber 6 from an external hydraulic system (not shown) via the oil port 7, the bladder 4 is located at approximately the center within the shell 2, as shown in FIG. Located in When the oil pressure applied to the oil chamber 6 changes in this state, the bladder 4 is displaced up and down, and the rod member 11 is accordingly displaced up and down. As the rod member 11 is vertically displaced, the ring member 13 is also vertically displaced, and the proximity switch 15 detects the vertical displacement of the ring member 13 and generates an appropriate on-off signal. Such a detection operation operates normally even if there are initial variations such as variations in the volume of the shell 2, variations in the pressure of the gas initially sealed in the gas chamber 5, and variations in the oil pressure of the system used. Furthermore, after long-term use, the high-pressure gas in the gas chamber 5 permeates and leaks through the rubber layer of the bladder 4 and the O-ring 9, and the operating center position of the bladder 4 is offset toward the gas chamber 5 side. It will still function normally.

[Effect of idea]

By configuring this idea as described above,
It eliminates the need for high-precision machining and assembly unlike conventional pressure switches, reducing costs.In addition, since it is integrated with the accumulator, it also saves space. It is possible to always detect oil pressure with high precision without being affected by various variations in initial processing and setting or changes over time, and it also eliminates the inconvenience of insulating electrodes while performing high pressure sealing. For example, it has excellent effects such as being able to very easily detect a hydraulic pressure change of several + kg/cm ² under a pressure of several hundred kg/cm ² .

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of the oil pressure detection device according to this invention, FIG. 2 is an enlarged sectional view of the main part of the device shown in FIG. FIG. 4 is a cross-sectional view of the device shown in FIG. 3, in which only high-pressure gas is sealed and no hydraulic pressure is applied. 1,21...Accumulator, 2,22...Ciel, 3,23...Holder, 4,24...Blader, 5,25...Gas chamber, 6,26...Oil chamber, 7,27...Oil Port, 8, 28... Poppet, 9, 29... O-ring, 10... Case, 11... Rod member, 12... Spring, 13...
...Ring member, 14...Button, 15...Proximity switch, 16...Enlarged portion, 17...Detection ring, 18...Elastic ring, 19...Step part, 30...
...Gas plug.

Claims (1)

[Scope of utility model registration request] Bladder 4 that isolates gas chamber 5 and oil chamber 6
The accumulator 1 is displaceable in response to changes in the oil pressure applied to the oil chamber 6, and the rod member 11 is fitted into the rod member 11, and the rod member 11 is displaceable in the longitudinal direction following the displacement of the bladder 4. A ring member 13 that is fitted together and that slides relatively to allow excessive displacement of the rod member 11 when the rod member 11 is displaced by a predetermined amount or more; Member 15 for detecting displacement from the outside without contact
A hydraulic pressure detection device comprising: