JP2001235380A - Pressure measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a low cost and thin pressure measuring device with high precision in measurement and having a long service life. SOLUTION: A hydraulic chamber is formed by a bottom plate 11, outside and inside side wall parts 12a, 12b, and a pressure pad 13. The outside side wall part 12a is formed by multiple large diameter ring-like members 16 of the same shape and size where the center part 16a of an approximately circular thin plate in the radial direction is inclined to the radial direction and an outer peripheral part 16b and an inner peripheral part 16c are formed in to a plain paralleled in the radial direction so as to be of different levels from each other in the axial direction. The inside side wall part 12b is formed by multiple small diameter ring-like 17 of the same shape and size as well. The diameter ring-like member 16 is connected in liquid-tight manner in a face-contact state of the outer peripheral part 16b to the bottom plate 11 and the pressure pad 13 and the small ring-like member 17 is connected in liquid-tight manner by welding and the like in a face-contacting state of an inner peripheral part 17c to the bottom plate 11 and the pressure pad 13 so as to form each of the members 16, 17 in bellows shape in a side view.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure measuring device, and more particularly to a pressure measuring device used for measuring a tension of an anchor for fixing an above-ground structure or a retaining wall to the ground.

[0002]

2. Description of the Related Art A pressure measuring device for measuring a pressure received from an object to be measured, particularly a pressure measuring device used when the pressure received from the object to be measured is high, is, for example, a load cell or a hermetically sealed state filled with hydraulic oil. There has been known a pressure measuring device that obtains an external pressure from a change in an internal pressure caused by a deformed hydraulic chamber receiving an external pressure and deforming. One of the uses of such a pressure measuring device is, for example, in an anchoring method generally used as a so-called mountain retaining method for preventing collapse of the ground such as an excavated slope, a ground structure or a retaining wall is fixed to the ground. There is a measurement of anchor tension. Here, the anchor method refers to a method in which an anchor cable 31 to which a stopper (not shown) from the ground is attached is buried in the ground G as shown in a cross-sectional view of FIG. The anchor cable 31 is penetrated through the retaining wall 32, the end portion is pulled out to the ground surface, inserted into the anchor head 33, and the pedestal portion 34 is sandwiched between the anchor head 33 and the retaining wall 32, and the retaining is performed by jacking or the like. Tension the anchor cable 31 by taking a reaction force against the wall 32
By being fastened, the retaining wall 32 is used as the anchor 36 that presses against the ground surface.

[0003] A plurality of anchors 36 are installed in a mountain stay, and these anchors 36 are installed by a pressure measuring device.
, That is, the pressure applied by the anchor head 33 to the retaining wall 32 via the pedestal portion 34 to observe the state of the retaining. Then, as a result of monitoring the tension of the anchor 36 over a long period of time by the pressure measuring device, for example, when the tension does not fluctuate, it indicates that the design of the mountain retaining is correct and the anchor 36 is functioning normally. . When the tension of the anchor 36 is reduced, the following may be considered. First, the function of the anchor 36 is normal, and the ground G is also stable. Since the tension of the anchor 36 exceeds the earth pressure of the ground G and pushes the ground G back, the extension of the anchor cable 31 decreases. It is thought that there is. In this case, the tension of all the anchors 36 often changes uniformly. It is also considered that the tension is reduced because the anchor 36 comes out of the ground G due to a defective portion (fixing layer) of the ground G where the anchor 36 is embedded or a poor construction.
In this case, the earth pressure to be received by the anchor 36 coming out of the ground G is to be received by another anchor, and the tension of the other anchor may increase.

[0004] When the tension of the anchor 36 is increasing, the following situation can be considered. First, it is possible that the retaining lands are receiving more earth pressure than expected. This may be due to various reasons, such as signs of landslides, improperly designed retaining glands, or increased soil pressure due to weather or seasonal factors that cause the ground G to contain more moisture. However, in any case, it is necessary to monitor the mountain retaining. It is also conceivable, for example, that an anchor not measuring the tension loses its function and that the anchor measuring the tension receives the earth pressure to be received by the anchor. In this way, the state of the buckle can be grasped from the fluctuation of the tension of each anchor.However, in order to grasp the buckle state in more detail, a pressure measuring device is provided for more anchors, if possible, for all anchors. It is desirable to measure the tension. Also,
Since the pressure measuring device is used by being incorporated into an anchor, it is desirable that the pressure measuring device has a life equivalent to the life of the mountain stay itself.

[0005]

However, when a load cell is used as a pressure measuring device, the number of installed load cells is limited because the load cell is very expensive, and the data obtained is also limited. Further, since the load cell is large in size, the amount of projection of the anchor head from the retaining wall becomes large, which impairs the scenery and is not preferable from the viewpoint of safety. In addition, a pressure measuring device (hereinafter referred to as a pressure measuring device 41) that obtains an external pressure from a change in an internal pressure caused by a deformation of an enclosed hydraulic chamber in response to an external pressure while being filled with hydraulic oil.
Is slightly cheaper than the load cell, but as described below, it is difficult to increase the measurement accuracy and its life is short due to its structure.

[0006] The pressure measuring device 41 is connected to the anchor 36 shown in FIG.
As shown in an exploded perspective view of an essential part of FIG. 1, a hydraulic chamber 42 having a substantially annular shape, and a hydraulic pressure measuring device 4 for measuring the internal pressure of the hydraulic chamber 42
And 3. 4 and FIG.
As shown in FIG. 5, the hydraulic chamber 42 is used between the anchor head 33 and the pedestal portion 34 with the supporting plates 46a and 46b interposed between the anchor head 33 and the pedestal portion 34, respectively. .

As shown in FIGS. 6 and 7, a hydraulic chamber 42 of the pressure measuring device 41 has a substantially annular ring-shaped metal plate 47 on both sides thereof, and a substantially annular annular plate having a substantially dish-shaped cross section. Are formed between these metal thin plates 48 and the ring-shaped metal plate 47 by welding the respective metal thin plates 48. A through hole 47 penetrating through both sides of the ring-shaped metal plate 47
a is provided, and the hydraulic chamber 42 has a structure communicating with both sides of the ring-shaped member 47. Here, FIG.
6A is a plan view of the hydraulic chamber 42, and FIG.
7 is a partially enlarged sectional view of the hydraulic chamber 42 as viewed from the direction indicated by arrows AA.

In the pressure measuring device 41, the contact area of the thin metal plate 48 forming the hydraulic chamber 42 with the supporting plates 46a and 46b is defined as a pressure receiving area, and the tension of the anchor 36 is determined from the pressure receiving area and the internal pressure of the hydraulic chamber 42. Although the force is obtained, the deformation of the hydraulic chamber 42 in the pressure measuring device 41 is caused by plastic deformation such that the side wall portion of the thin metal plate 48 having a dish-shaped cross section is crushed. (A state shown in FIG. 7A) and a state where an external pressure is applied (FIG. 7A).
(State shown in (b)), the pressure receiving area changed, and it was difficult to ensure the measurement accuracy. In addition, since the deformation of the thin metal plate 48 is plastic deformation, the pressure measuring device 41 gradually reduces the accuracy of the pressure receiving area of the hydraulic chamber 42 due to long-term use, and the pressure measuring device 41 is changed in accordance with a change in the external pressure. The metal sheet 48 is deformed repeatedly.
However, there is also a problem in terms of service life, such as that the strength tends to decrease due to fatigue.

Here, since the pressure measuring device used for the anchor 36 is usually used in a state where it is exposed to the open air,
At least once a day, fluctuations in air temperature cause expansion and contraction of hydraulic oil, and the internal pressure of the hydraulic chamber 42 fluctuates. Also,
For example, when the weather fluctuates within one day, the hydraulic oil expands by being heated by, for example, direct sunlight or the like, and contracts by being cooled by rainfall or the like.
Since the number of deformations of the metal sheet 48 forming the second member 2 further increases, the life thereof is substantially several years when the conventional pressure measuring device 41 is used.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a low-cost, low-cost pressure measuring device having high measurement accuracy, a long life, and a low cost.

[0011]

According to a first aspect of the present invention, there is provided a pressure measuring apparatus, comprising:
A pressure measuring device that obtains an external pressure from a change in internal pressure caused by an external pressure deforming a hydraulic chamber sealed in a state filled with hydraulic oil, and a bottom plate having a substantially annular shape, and a substantially annular shape. A pressure receiving plate, an outer side wall connecting the bottom plate and the outer peripheral edge of the pressure receiving plate, an inner side wall connecting the bottom plate and the inner peripheral edge of the pressure receiving plate, the bottom plate, the outer side wall, and the inner side. A hydraulic pressure measuring device that measures the pressure of hydraulic oil filled in a hydraulic chamber formed into a substantially annular shape by the side wall portion and the pressure receiving plate, and the outer side wall portion includes:
The same shape in which a radially intermediate portion of a substantially annular thin plate is inclined with respect to the radial direction so that an outer peripheral portion and an inner peripheral portion are planes substantially parallel to the radial direction and stepped in the axial direction with respect to each other. At least two or more large-diameter ring-shaped members of the same size are connected in a liquid-tight manner in the axial direction in different vertical directions, and the inner side wall portion is a radially intermediate portion of a thin plate having a substantially annular shape. At least two ring members of the same shape and the same size whose outer peripheral portion and inner peripheral portion are inclined with respect to the radial direction, and whose outer peripheral portion and inner peripheral portion are substantially parallel to the radial direction and are planes that are stepped in the axial direction. As described above, the upper and lower ends of these large-diameter ring-shaped members are connected to the bottom plate and the pressure-receiving plate, respectively. The small-diameter rings which are closely connected and located at the upper and lower ends of these small-diameter ring-shaped members Said peripheral portion each member bottom plate,
It is characterized by being connected to the pressure receiving plate in a liquid-tight manner.

In the pressure measuring device thus constructed, the hydraulic chamber connects the substantially annular bottom plate, the substantially annular pressure receiving plate, and the outer peripheral edges of the bottom plate and the pressure receiving plate to each other. It is formed by an outer side wall and an inner side wall connecting these inner peripheral edges of the bottom plate and the pressure receiving plate. And
Among the large-diameter ring-shaped members constituting the outer side wall, the bottom plate,
The large-diameter ring-shaped member connected to the pressure receiving plate
The outer peripheral portion is connected to the pressure-receiving plate, and among the small-diameter ring-shaped members constituting the inner side wall portion, the small-diameter ring-shaped member connected to the bottom plate and the pressure-receiving plate connects the inner peripheral portion to the bottom plate and the pressure-receiving plate. Since the pressure receiving area is thereby determined, the pressure receiving area is always kept constant even if these large-diameter and small-diameter ring-shaped members are deformed by receiving an external pressure. Also, when subjected to external pressure, these large-diameter and small-diameter ring-shaped members act in the same manner as a disc spring, and the deformation of the hydraulic chamber is caused by the elastic deformation of the intermediate part, so that fatigue occurs on the outer side wall and the inner side wall. It becomes difficult. Here, by increasing the number of large-diameter, small-diameter ring-shaped members constituting the outer side wall portion and the inner side wall portion,
The elastic deformation range of the outer side wall portion and the inner side wall portion can be widened, and the durability against repeated deformation of the hydraulic chamber can be improved to extend the life.

[0013] In the pressure measuring device according to the second aspect,
The hydraulic pressure measuring device has a cylinder connected to the hydraulic chamber, a plunger inserted into the cylinder, and a direction in which the plunger pushes the hydraulic oil back into the hydraulic chamber against the internal pressure of the hydraulic chamber. A biasing member for biasing the plunger, wherein the plunger is arranged to indicate a change in the internal pressure in the hydraulic chamber by a change in an amount of protrusion from the cylinder.

In a conventional pressure measuring device, as a hydraulic pressure measuring device for measuring the internal pressure of the hydraulic chamber, for example, a Bourdon tube for visually confirming the internal pressure of the hydraulic chamber, or converting a measured value of the internal pressure of the hydraulic chamber into an electric signal. Then, a pressure sensor for storing measurement data in a data logger or transmitting the measurement data to a remote place via a communication device is used. However, these Bourdon tubes and pressure sensors are susceptible to deterioration over time. In particular, when a pressure measuring device is used for an anchor, the anchor needs to be guaranteed at a temperature of about -25 ° C. to + 80 ° C. in order to maintain its performance even in the midwinter and midsummer, for example, because it is installed in a mountainous area. The pressure sensor having such performance is expensive, and the life of the electric cord and the connector connected to the pressure sensor is considered to be about 5 years under the sun exposure. In the pressure measuring device according to the present invention, the hydraulic pressure measuring device is purely mechanical and simple in that the plunger urged by the urging member receives the internal pressure of the hydraulic chamber and obtains the internal pressure of the hydraulic chamber from the amount of protrusion from the cylinder. With such a configuration, even under a severe environment, functional deterioration due to aging is unlikely to occur, and durability against repeated fluctuations in the internal pressure of the hydraulic chamber is also improved. Here, the internal pressure of the hydraulic chamber can be visually confirmed based on the amount of protrusion of the plunger from the cylinder.

In the pressure measuring device according to the third aspect,
The oil pressure measuring device may include a sensor that detects an internal pressure in the hydraulic chamber from an amount of protrusion of the plunger from the cylinder. Conventional hydraulic pressure measuring devices, such as Bourdon tubes and pressure sensors, are susceptible to deterioration due to aging, but are connected to the hydraulic chamber via pipes or the like, so that the hydraulic pressure in the hydraulic chamber is maintained. These oil pressure measuring devices could not be replaced as they were. In the pressure measuring device of the present invention, the hydraulic pressure measuring device obtains from the amount of protrusion of the plunger from the cylinder connected to the hydraulic pressure chamber, and the sensor for detecting the internal pressure of the hydraulic pressure chamber is separated from the hydraulic pressure chamber. The sensor can be replaced while maintaining the oil pressure in the chamber.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the pressure measuring device of the present invention will be described below with reference to FIGS. Here, FIG. 1 is a diagram showing a configuration of a pressure measuring device according to an embodiment of the present invention. FIG. 1A is a partially cutaway plan view of the pressure measuring device, and FIG. B in (a)
2 (a) is an enlarged view of a main part in FIG. 1 (a), FIG. 2 (b) is a cross-sectional view taken along CC in FIG. 2 (a), and FIG. It is a principal part enlarged view in b). The pressure measuring device 1 is a pressure measuring device that obtains an external pressure from a change in an internal pressure caused by a hydraulic chamber that is hermetically sealed in a state of being filled with hydraulic oil and deformed by receiving an external pressure.
As shown in (b), a substantially square plate-shaped base 2 having a substantially circular through hole 2a formed at the center and a substantially annular groove 2b formed concentrically with the through hole 2a on the upper surface. , Groove 2b
And a hydraulic chamber 3 provided in the groove 2b so as to slightly protrude from the upper surface of the base 2 in the groove 2b, and a hydraulic pressure connected to the hydraulic chamber 3 through the base 2. And a measuring device 4. Here, the depth of the groove 2b of the base 2 is set, for example, to a depth at which the hydraulic chamber 3 is housed in the groove 2b and does not receive any further external pressure when the hydraulic chamber 3 is deformed by a certain amount or more. Can be prevented from being damaged by receiving an external pressure exceeding the allowable limit.

As shown in FIG. 2, the base 2 is formed with pipes 6 which are bifurcated from the bottom surface 5 of the groove 2b and communicate with the two side surfaces 2c and 2d of the base 2, respectively. This conduit 6
Are connected to the inside of the hydraulic chamber 3 through a bottom plate 11 (described later) constituting the hydraulic chamber 3, and
The branch path 6a communicating with the cylinder 7 has a substantially cylindrical cylinder 7 into which a plunger 21 to be described later is inserted, the diameter of the side face 2c being enlarged.
It has been. The branch path 6b communicating with the side surface 2d is also enlarged in diameter on the side surface 2d side to form a substantially cylindrical screw hole 9 to which the valve 8 is attached. Valve 8 and branch 6
“b” serves as a lubrication port for the hydraulic oil O into the hydraulic chamber 3 and an air vent in the hydraulic chamber 3. The bottom surface 5 of the groove 2b is liquid-tightly sealed between the bottom surface of the bottom plate 11 constituting the hydraulic chamber 3 and the bottom surface 5 of the groove 2b around the opening end 6c on the bottom surface 5 side of the conduit 6. A sealing material 10 is provided. In the present embodiment, as the sealing material 10, an O-ring installed in a substantially annular sealing groove 5a formed around the open end 6c of the conduit 6 on the bottom surface 5 of the groove 2b is used. .

As shown in FIGS. 1B and 3, the hydraulic chamber 3 has a substantially annular bottom plate 11 mounted on the bottom surface of the groove 2b, and a substantially annular pressure receiving plate for receiving external pressure. 13, an outer side wall portion 12a connecting the outer peripheral edges of the bottom plate 11 and the pressure receiving plate 13, and an inner side wall portion 12b connecting the inner peripheral edges of the bottom plate 11 and the pressure receiving plate 13 to each other. The bottom plate 11 supports the pressure receiving plate 13 via the outer and inner side wall portions 12a and 12b, and has a sufficient thickness to withstand an external pressure expected to be received by the hydraulic chamber 3. Also,
As shown in FIG. 2 (b), the bottom plate 11 has a communication hole 11a extending from the bottom surface to the top surface in communication with the open end 6c of the conduit 6 formed on the bottom surface 5 of the groove 2b. Thereby, the hydraulic chamber 3 is connected to the pipeline 6 of the base 2.
Then, as shown in FIG.
Overhangs 11b each having a bolt insertion hole 11c are provided at radially inner and outer peripheral sides of the bottom plate 11 with respect to the bottom plate 1a. It can be fixed to the bottom surface 5 of the groove 2b in close contact. Here, the overhang portion 11b is
Not only this portion but also an arbitrary number can be provided at an arbitrary position of the bottom plate 11 as needed. In the present embodiment,
In consideration of the mounting balance of the bottom plate 11 to the base 2, overhangs 11 b are provided at the edges located on the inner peripheral side and the outer peripheral side on the opposite side of the center of the bottom plate 11.

The outer side wall portion 12a is shown in FIGS.
As shown in FIG. 5, the inner side wall portion 12b has an outer diameter smaller than the inner diameter of the large-diameter ring-shaped member 16. It is constituted by a plurality of small-diameter ring-shaped members 17 having an annular shape.

As shown in FIG. 3, the large-diameter ring-shaped member 16 has an outer peripheral portion 16b and an inner peripheral portion 16c in which a radially intermediate portion 16a of a substantially annular thin plate is inclined with respect to the radial direction.
Are planes that are substantially parallel to the radial direction and that are stepped from each other in the axial direction. These large-diameter ring-shaped members 16 are connected in a liquid-tight manner in the axial direction with their vertical directions being different from each other, and are connected in a state where the inner peripheral portions 16c or the outer peripheral portions 16b are in surface contact with each other. Have been. In the present embodiment, four large-diameter ring-shaped members 16 are connected. For example, when connecting the outer peripheral portions 16b, the outer peripheral edges 16
d are welded together. (Furthermore, the boundary portions between the outer peripheral portion 16b and the intermediate portion 16a may be welded to each other to secure the connection strength between them). Similarly, when the inner peripheral portions 16c are connected to each other, for example, the inner peripheral edges 16e are welded to each other, and further, the boundary portions between the inner peripheral portions 16c and the intermediate portion 16a are welded to each other, so that their connection strengths are increased. Is secured.

The large-diameter ring members 16 located at the upper and lower ends of the large-diameter ring members 16 have their outer peripheral portions 16b in surface contact with the upper surface of the bottom plate 11 and the lower surface of the pressure receiving plate 13, respectively. They are connected in a liquid-tight manner by welding or the like. In the present embodiment, the large-diameter ring-shaped member 16 connected to the bottom plate 11 and the pressure receiving plate 13 is
1. The pressure receiving plate 13 is connected by welding a boundary portion between the outer peripheral portion 16b and the intermediate portion 16a and further welding an outer peripheral edge 16d. Thereby, the connection strength of the large-diameter ring-shaped member 16 to the bottom plate 11 and the pressure receiving plate 13 is ensured, and the outer peripheral edge of the surface F in which the external pressure acts on the hydraulic oil O filled in the hydraulic chamber 3 in the pressure receiving plate 13 is determined. I do.

The small-diameter ring-shaped member 17 has a substantially annular shape in which the outer diameter is smaller than the inner diameter of the large-diameter ring-shaped member 16. The portion 17b and the inner peripheral portion 17c are planes that are substantially parallel to the radial direction and that are stepped in the axial direction. These small diameter ring-shaped members 17 are similar to the large diameter ring-shaped members 16.
They are connected in a liquid-tight manner in the axial direction with their vertical directions different from each other.
b are connected in a state where they are in surface contact with each other. In the present embodiment, four small-diameter ring-shaped members 17 are connected. For example, when connecting the outer peripheral portions 17b, the boundary portions between the outer peripheral portions 17b and the intermediate portion 17a are welded,
Further, the outer peripheral edges 17d are welded to each other to secure the connection strength therebetween. Similarly, for example, the inner peripheral portion 17
In the case where c are connected to each other, their inner peripheral edges 17e are welded to each other (further, the boundaries between the inner peripheral portions 17c and the intermediate portion 17a may be welded to each other to secure the connection strength therebetween. ).

Out of these small-diameter ring-shaped members 17, the small-diameter ring-shaped members 17 positioned at the upper and lower ends, opposite to the large-diameter ring-shaped member 16, respectively have an inner peripheral portion 17c on the upper surface of the bottom plate 11, 13 is connected in a liquid-tight manner by welding or the like in a state of being in surface contact with the lower surface of 13. In the present embodiment, the small-diameter ring-shaped members 17 connected to the bottom plate 11 and the pressure receiving plate 13 are welded to the bottom plate 11 and the pressure receiving plate 13, respectively, at a boundary between the inner peripheral portion 17c and the intermediate portion 17a. Further, the inner peripheral edge 17e is connected by welding. This ensures these connection strengths, and determines the inner peripheral edge of the surface F on which the external pressure is applied to the hydraulic oil O filled in the hydraulic chamber 3 in the pressure receiving plate 13 to keep the radial width W of the surface F constant. And the pressure receiving area is always constant.

Here, the intermediate portion 1 of the small diameter ring-shaped member 17
The radial width of each of the outer peripheral portion 17b and the inner peripheral portion 17c is equal to the intermediate portion 16 of the large-diameter ring-shaped member 16.
a, the radial width of the outer peripheral portion 16b, and the radial width of the inner peripheral portion 16c, and the radial inclination angle of the intermediate portion 17a is also equal to the radial inclination angle of the intermediate portion 16a of the large-diameter ring-shaped member 16. . Thereby, the cross-sectional shapes of the outer side wall portion 12a and the inner side wall portion 12b become substantially bellows as shown in FIG. The thickness of the small-diameter ring-shaped member 17 is equal to the thickness of the large-diameter ring-shaped member 16, and in the present embodiment, these thicknesses are set to about 1 mm.

The pressure receiving plate 13 has outer and inner side wall portions 12a,
It is formed thicker than the large-diameter ring-shaped member 16 and the small-diameter ring-shaped member 17 constituting 12b, and has a thickness of about 3 mm in the present embodiment. As a result, when an external pressure is applied, the outer and inner side walls 12a and 12b are first deformed to reduce the variation in the pressure receiving area due to the deformation of the pressure receiving plate 13. In the pressure receiving plate 13, the area of the surface surrounded by the outer side wall portion 12 a and the inner side wall portion 12 b, that is, the area of the surface F for applying an external pressure to the hydraulic oil O filled in the hydraulic chamber 3 is the pressure receiving area of the hydraulic chamber 3. Becomes

As shown in FIG. 2, the hydraulic pressure measuring device 4 includes a cylinder 7 formed in the branch path 6a of the pipe line 6 of the base 2 described above, 21
a, a bushing 22 which is attached to the open end of the cylinder 7 with the plunger 21 inserted and which prevents the plunger 21 from falling out of the cylinder 7, and a bushing 22 and the plunger 21 in the cylinder 7. The plunger 21 is disposed between the plunger 21 and the enlarged diameter portion 21a.
A spring 23 (biasing member) for urging the hydraulic oil O back into the hydraulic chamber 3 against the internal pressure of the hydraulic chamber 3 and a position sensor 24 for detecting the amount of protrusion of the plunger 21 from the cylinder 7. It is configured.

The plunger 21 has a substantially cylindrical shape with a diameter of about 3 mm on the tip side from the enlarged diameter portion 21a, and a nose 21b inserted deeper into the branch passage 6a than the cylinder 7.
Are formed. In addition, the nose portion 21b, the enlarged diameter portion 21
a, and a sealing material 26 such as an O-ring is provided on the outer periphery of a portion inserted into the bushing 22, and the plunger 21 is sealed in the longitudinal direction while sealing the branch path 6a and the cylinder 7 in a liquid-tight manner. It is slidable. In the present embodiment, a projection 21c for operating the position sensor 24 is provided on the rear end side of the plunger 21.

The spring constant of the spring 23 is, for example, every time the internal pressure of the hydraulic chamber 3 changes by 2 MPa, the plunger 21 urged by the spring 23 moves by 1 m along its longitudinal direction.
It is set to move by m. The position sensor 24 is connected to an information processing device L such as a data logger or a remote monitoring device by wire or wirelessly.
It is possible to accumulate information on the amount of protrusion of the plunger 21 from the hydraulic chamber 3, that is, the internal pressure of the hydraulic chamber 3, or to monitor the internal pressure of the hydraulic chamber 3 from a remote place. In the present embodiment, the position sensor 24 is, for example,
Is projected by a predetermined amount, a microswitch operated by a projection 21c provided on the rear end side of the plunger 21 is used, and is operated when the internal pressure of the hydraulic chamber 3 reaches a predetermined pressure. I have. The micro switch is, for example, a plunger 21 in a retreat limit position (position of the plunger 21 when an allowable limit of external pressure is applied to the hydraulic chamber 3) or a forward limit position (plunger 21 in a state where no external force is applied to the hydraulic chamber 3). ), Or when operated by the projection 21c of the plunger 21 when a predetermined reference pressure is applied to the hydraulic chamber 3, the number of installation is arbitrary. Here, in the hydraulic pressure measuring device 4, for example, a scale is provided in the plunger 21 in the longitudinal direction so that the amount of protrusion from the bushing 22, that is, the amount of protrusion of the plunger 21 from the cylinder 7 can be visually measured. Good. This scale may be a scale indicating the amount of protrusion of the plunger 21 or a scale indicating the amount of protrusion of the plunger 21 converted into the internal pressure of the hydraulic chamber 3 or the external pressure applied to the hydraulic chamber 3. Alternatively, a scale may be attached to the base 2 along the longitudinal direction of the plunger 21 so that the amount of protrusion of the plunger 21 can be measured visually.

Hereinafter, as an example of use of the pressure measuring device 1 configured as described above, a case where the pressure measuring device 1 is used for measuring the tension of the anchor 36 shown in FIG. 4 will be described. The pressure measuring device 1 connects the hydraulic chamber 3 to the anchor head 33.
The anchor cable 32 is disposed between the anchor head 32 and the pedestal portion 34 in a state where the anchor cable 32 is pulled out, and the anchor cable 31 pulled out to the ground surface is inserted into the anchor head 32 through the through hole 2a of the base 2, and in this state, a mountain retaining wall is jacked or the like. The anchor cable 31 is assembled into the anchor 36 by tensioning and fastening the anchor cable 31 by taking a reaction force to the anchor cable 32. When the pressure receiving plate 13 of the hydraulic chamber 3 receives the tension (external pressure) of the anchor 36, the outer side wall 12a and the inner side wall 12b are elastically deformed, and the large-diameter ring-shaped member 16 forming the outer side wall 12a is formed. The intermediate portion 17a of the small-diameter ring-shaped member 17 forming the intermediate portion 16a and the inner side wall portion 12b is elastically deformed to change the volume of the hydraulic chamber 3 and increase the internal pressure of the hydraulic chamber 3. Then, a part of the hydraulic oil O in the hydraulic chamber 3 is sent to the branch path 6 a of the pipe 6, and the nose portion 21 of the plunger 21 of the hydraulic pressure measuring device 4.
b, the plunger 21 is moved in a direction to protrude from the cylinder 7 against the urging force of the spring 23.

Here, the magnitude of the tension of the anchor 36 received by the hydraulic chamber 3 is determined by the difference between the amount of protrusion of the plunger 21 from the cylinder 7 under no load and the amount of protrusion under external pressure. It is obtained from the pressure receiving area of the hydraulic chamber 3 as follows. First, the pressure that the nose portion 21b receives from the internal pressure of the hydraulic chamber 3 is calculated from the displacement amount of the spring 23 and the spring constant of the spring 23. The magnitude of the tension of the anchor 36 received by the hydraulic chamber 3 is calculated by multiplying this pressure by the ratio of the pressure receiving area of the hydraulic chamber 3 to the area of the tip end surface of the nose portion 21b, that is, the area of the surface F of the pressure receiving plate 13. Is done. Here, the pressure receiving area of the hydraulic chamber 3, that is, the area of the surface F surrounded by the large-diameter ring-shaped member 16 and the small-diameter ring-shaped member 17 in the pressure receiving plate 13 is always constant.
The measurement accuracy of the tension of the anchor 36 received by the operator is ensured.

Here, the position sensor 24 composed of a microswitch for detecting the position of the plunger 21 is moved to a position operated by the projection 21c of the plunger 21 in a state where the tension of the anchor 36 is at the upper limit or lower limit of the appropriate range. And by monitoring the status of these position sensors 24, it is possible to know whether the anchor 36 is functioning normally. And these position sensors 2
4, the position of the plunger 21, that is, the displacement of the tension of the anchor 36 can be detected in more detail. It is also possible to know.

According to the pressure measuring device 1 configured as described above, the deformation of the hydraulic chamber 3 is caused by the elastic deformation of the outer side wall 12a and the inner side wall 12b. The outer side wall portion 12a and the inner side wall portion 12b are hardly subject to fatigue.
The strength of the hydraulic chamber 3 is prolonged because the strength of the inner wall portion 12a and the inner side wall portion 12b is not easily reduced. Further, since the hydraulic pressure measuring device 4 has a purely mechanical and simple configuration excluding the position sensor 24, the functional deterioration due to aging does not easily occur even in a severe environment, and the durability against the repetitive fluctuation of the internal pressure of the hydraulic chamber. Performance can also be improved. Also position sensor 2
Since the pressure chamber 4 is independent of the hydraulic chamber 3, it can be replaced while maintaining the internal pressure of the hydraulic chamber 3.

In the above embodiment, the outer side wall 12a of the hydraulic chamber 3 of the pressure measuring device 1 is formed by connecting four large-diameter ring-shaped members 16, and the inner side wall 12b is formed by four small-diameter ring-shaped members. Although the example in which the members 17 are connected to each other is shown,
Without being limited to this, at least two or more may be connected, and by connecting more large-diameter ring-shaped members 16 and small-diameter ring-shaped members 17, these outer side wall portions 12 a and inner side wall portions 12 b are connected. By increasing the elastic deformation range, the durability against repeated deformation of the hydraulic chamber 3 can be further improved, and the life can be prolonged. In the above-described embodiment, the pipe 6 and the cylinder 7 constituting the oil pressure measuring device 4 are not formed on the base 2 but are formed by independent parts, so that the base 2 may be omitted. Absent.

[0034]

According to the pressure measuring device of the first aspect of the present invention, among the large-diameter ring-shaped members constituting the outer side wall, the large-diameter ring-shaped member connected to the bottom plate and the pressure-receiving plate is composed of these members. The outer peripheral portion is connected to the bottom plate and the pressure receiving plate, and among the small-diameter ring-shaped members constituting the inner side wall portion, the small-diameter ring-shaped member connected to the bottom plate and the pressure receiving plate has an inner peripheral portion connected to the bottom plate and the pressure receiving plate. And the pressure receiving area is determined. Therefore, even if these large-diameter and small-diameter ring-shaped members are deformed by receiving an external pressure, the pressure receiving area is always kept constant, and the measurement accuracy can be secured. In addition, the large-diameter and small-diameter ring-shaped members act in the same manner as a coned disc spring when subjected to external pressure, and the deformation of the hydraulic chamber is caused by the elastic deformation of the intermediate portion, so that fatigue occurs on the outer side wall and the inner side wall. And the life of the hydraulic chamber can be extended. Here, by increasing the number of large-diameter ring-shaped members forming the outer side wall portion and the number of small-diameter ring-shaped members forming the inner side wall portion, it is possible to increase the elastic deformation range of the outer side wall portion and the inner side wall portion, The durability against repeated deformation of the hydraulic chamber can be improved and the life can be extended.

According to the pressure measuring device of the second aspect, since the hydraulic pressure measuring device has a purely mechanical and simple structure, it is unlikely that its function will deteriorate due to aging even in a harsh environment, The durability against repeated fluctuations in the internal pressure can also be improved.

According to the pressure measuring device of the third aspect, the hydraulic pressure measuring device obtains from the amount of protrusion of the plunger from the cylinder connected to the hydraulic pressure chamber, and the sensor for detecting the internal pressure of the hydraulic pressure chamber is separated from the hydraulic pressure chamber. Therefore, the sensor can be replaced while maintaining the hydraulic pressure in the hydraulic chamber.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a pressure measuring device according to an embodiment of the present invention, wherein FIG. 1 (a) is a partially cutaway plan view of the pressure measuring device, and FIG. 1 (b) is FIG. BB in
It is arrow sectional drawing.

2A and 2B are diagrams illustrating a configuration of a pressure measuring device according to an embodiment of the present invention. FIG. 2A is an enlarged view of a main part in FIG. 1A, and FIG. CC in ())
It is arrow sectional drawing.

FIG. 3 is a diagram showing a configuration of a pressure measuring device according to an embodiment of the present invention, and is an enlarged view of a main part in FIG. 1 (b).

FIG. 4 is a cross-sectional view showing a schematic configuration of an anchor method which is one of applications of the pressure measuring device.

FIG. 5 is an exploded perspective view of a main part showing a configuration of an anchor.

6 (a) is a plan view of the hydraulic chamber, and FIG. 6 (b) is a cross-sectional view of the hydraulic chamber taken along the line AA. FIG. is there.

FIG. 7 is an enlarged view of the hydraulic chamber shown in FIG.
FIG. 7A shows a state where the hydraulic chamber is not subjected to external pressure,
FIG. 7B shows a state in which the hydraulic chamber has received an external pressure.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Pressure measuring device 3 Hydraulic chamber 4 Hydraulic pressure measuring device 7 Cylinder 11 Bottom plate 12a Outer side wall part 12b Inner side wall part 13 Pressure receiving plate 16 Large-diameter ring-shaped member 17 Small-diameter ring-shaped member 16a, 17a Intermediate part 16b, 17b Outer part 16c, 17c Inner circumference 21 Plunger 23 Spring (biasing member) 24 Position sensor

Claims (3)

[Claims] 1. A pressure measuring device for obtaining an external pressure from a fluctuation of an internal pressure caused by an external pressure deforming a sealed hydraulic chamber in a state of being filled with hydraulic oil, comprising: a bottom plate having a substantially annular shape; A pressure receiving plate having a substantially annular shape,
An outer side wall connecting the outer peripheral edges of the bottom plate and the pressure receiving plate; an inner side wall connecting the inner peripheral edges of the bottom plate and the pressure receiving plate; and the bottom plate, the outer side wall, the inner side wall, and the pressure receiving plate. And a hydraulic pressure measuring device for measuring the pressure of the hydraulic oil filled in the hydraulic chamber formed in a substantially annular shape by the outer side wall portion, wherein the radially intermediate portion of the thin annular plate having a substantially annular shape is provided. At least two or more large-diameter ring-shaped members which are inclined with respect to the radial direction, and whose outer peripheral portion and inner peripheral portion are substantially parallel to the radial direction and have flat surfaces that are stepped in the axial direction with respect to each other. The upper and lower side walls are connected in a liquid-tight manner in the axial direction, and the inner side wall portion is formed such that a radially intermediate portion of a thin plate having a substantially annular shape is inclined with respect to the radial direction and has an outer peripheral portion. A plane whose inner peripheral portion is substantially parallel to the radial direction and is stepped in the axial direction with respect to each other. At least two or more small-diameter ring-shaped members of the same shape and the same size are connected in a liquid-tight manner in the axial direction by changing the vertical direction. Each of the ring-shaped members has an outer peripheral portion connected to the bottom plate and the pressure receiving plate in a liquid-tight manner. Of these small-diameter ring-shaped members, small-diameter ring-shaped members located at the upper and lower ends respectively have an inner peripheral portion having the bottom plate and the pressure receiving plate. A pressure measuring device, which is connected to the plate in a liquid-tight manner. 2. The hydraulic pressure measuring device comprises: a cylinder connected to the hydraulic chamber; a plunger inserted into the cylinder; and the hydraulic oil is applied to the hydraulic chamber by causing the plunger to resist the internal pressure of the hydraulic chamber. And a biasing member for biasing the plunger in a direction in which the plunger protrudes from the cylinder to indicate a change in the internal pressure in the hydraulic chamber. 2. The pressure measuring device according to 1. 3. The hydraulic pressure measuring device according to claim 2, further comprising a sensor for detecting an internal pressure in the hydraulic chamber from an amount of protrusion of the plunger from the cylinder.
A pressure measuring device as described.