JP7369395B2 - fluid pressure actuator - Google Patents

Description

The present invention relates to a fluid pressure actuator that is driven by supplying and discharging a working fluid.

Hydraulic actuators, which are widely used as fluid pressure actuators, use hydraulic oil as the working fluid.
Due to the structure of hydraulic actuators, there is a risk of hydraulic oil leaking during operation, so when adopting a hydraulic actuator, consider the installation location, operating mode, etc., assuming that hydraulic oil will leak. There must be.
For this reason, if leaked hydraulic oil contaminates the surrounding environment, hydraulic fluid may be removed via a hydraulic actuator that uses water-based hydraulic fluid (hydraulic water), which has a lower environmental impact than hydraulic oil. The driving force of the actuator is output.
An example of a configuration in which such a hydraulic actuator and a hydraulic actuator are combined is disclosed in Patent Document 1.

Japanese Patent Application Publication No. 2018-044589

By the way, Patent Document 1 proposes a method for externally supplying working water to a hydraulic actuator using a working water supply device.
In the case of this method of supplying working water from the outside, it is necessary to electrically control the flow rate adjustment valve, sensors, etc. on the hydraulic actuator side.
However, in a configuration in which the control unit and sensors are placed on the hydraulic actuator side, it is difficult to operate the control unit and sensors in harsh environments where it is difficult for people to approach, such as a radiation environment with high radioactivity levels. The problem was that the system broke down, malfunctioned, and did not function properly.

The present invention was devised in view of the above-mentioned problems, and can be operated in harsh environments where it is difficult for people to approach, such as radiation environments with high radioactivity levels, without malfunctioning. The object of the present invention is to provide a fluid pressure actuator that can be operated safely by an operator.

In order to achieve the above object, the fluid pressure actuator according to the present invention is capable of supplying and discharging a drive-side working fluid made of an incompressible fluid through a drive piping to a conversion pressure chamber formed inside a conversion unit main body. The converting pressure chamber is divided into a driving pressure chamber and a driven pressure chamber to which a driven side working fluid made of an incompressible fluid can be supplied and discharged through driven piping, and includes a displacement body arranged to be displaceable within the conversion pressure chamber. When either the driving-side working fluid or the driven-side working fluid is supplied to the conversion pressure chamber, the displacement body is displaced according to the supplied amount, and the driving-side working fluid and the driven-side working fluid a conversion unit comprising a pull-side conversion unit configured with a conversion unit in which the other side of the driven-side working fluid is discharged from the conversion pressure chamber; and a push-side conversion unit configured with the conversion unit; A detection means for measuring the amount of displacement of the displacement body, a drive section for supplying the drive side working fluid to the drive pipe, a driven section body pressure chamber formed inside the driven section body, a pull side pressure chamber, The drive side working fluid is divided into a push side pressure chamber and an internal space formed inside the absorption cylinder main body and a driven part that is disposed displaceably within the driven part main body pressure chamber. The absorption cylinder is arranged so as to be displaceable within the absorption cylinder body while being divided into an absorption liquid pressure chamber that can be supplied and discharged through the drive piping and an absorption gas pressure chamber that can supply and discharge compressible gas set at a predetermined pressure. a pull-side absorption unit comprising an absorption piston that absorbs the load by displacing the absorption piston in accordance with the load when an excessive load is input to the drive-side working fluid; an absorption mechanism comprising a push-side absorption unit configured with the absorption unit, and the pull-side conversion unit is configured such that the driven pressure chamber communicates with the pull-side pressure chamber through the driven piping, The drive pressure chamber communicates with the absorption liquid pressure chamber of the pull-side absorption unit through an absorption liquid pipe that communicates with the drive pipe, and the push-side conversion unit communicates with the absorption liquid pressure chamber of the pull-side absorption unit through an absorption liquid pipe that communicates with the drive pipe. The drive pressure chamber communicates with the absorption liquid pressure chamber of the pushing side absorption unit through an absorption liquid pipe that communicates with the drive pipe while communicating with the side pressure chamber.

According to the present invention, even when operating in harsh environments where it is difficult for people to approach, such as a radiation environment with high radioactivity levels, operators can safely operate the vehicle without malfunctioning. A hydraulic actuator can be provided.

FIG. 1 is a configuration diagram showing a fluid pressure actuator of a first embodiment. It is a block diagram which shows the 1st other aspect of 1st Embodiment. It is a graph which shows the characteristic of the absorption mechanism which comprises a 1st other aspect. It is a block diagram which shows the 2nd another aspect of 1st Embodiment. Graphs showing the characteristics of the absorption mechanism constituting the second alternative embodiment, (a) is when the set pressure value is set small, (b) is when the set pressure value is set large, and (c) is (a) (b). ) is a graph showing a combination of (a) is a configuration diagram showing a third alternative aspect of the first embodiment, (b) is a configuration diagram showing a fourth alternative aspect of the first embodiment, and (c) is a configuration diagram showing a fifth alternative aspect of the first embodiment. FIG. It is a block diagram which shows the fluid pressure actuator of 2nd Embodiment. It is a list which shows the function of the absorption mechanism which constitutes the fluid pressure actuator of a 2nd embodiment.

Embodiments of the present invention will be described in detail with reference to the drawings as appropriate. Identical components are given the same reference numerals and redundant explanations will be omitted.
As shown in FIG. 1, the fluid pressure actuator AC of the present embodiment includes a drive section 1, a driven section 2, a conversion section 3, a displacement detection means 4, an absorption mechanism 5, a reservoir tank 6, a pressure detection means 7, a control section ( (not shown).

The drive unit 1 and the conversion unit 3 are linked by a drive pipe PL1 through which incompressible hydraulic fluid FL1 (drive-side working fluid) circulates.
Further, the converting section 3 and the driven section 2 are linked by a driven pipe PL2 through which incompressible working water FL2 (driven side working fluid) circulates.
Then, the pressure of the hydraulic fluid FL1 increased by the drive section 1 is transmitted to the hydraulic fluid FL2 via the conversion section 3.

Further, the fluid pressure actuator AC of the present embodiment is configured such that the driven portion 2 performs both the pushing operation and the retracting operation by the pressure transmitted to the working water FL2.
Note that the pipes such as the drive pipe PL1 and the driven pipe PL2 are made of a strong material, such as a metal pipe, that does not expand in diameter even when the working fluid flowing therein is pressurized.
Since the piping is made of a strong material that does not expand in diameter, pumping loss is eliminated, so the distance between the drive section 1 and the conversion section 3 and between the conversion section 3 and the driven section 2 is reduced. Can be connected in expanded state.

Next, the respective configurations of the driving section 1, the driven section 2, and the converting section 3 will be explained (see FIG. 1).
The drive unit 1 includes an oil storage tank 10, a pump 11, a pressure regulator 12, and a control valve 13.
The oil storage tank 10 is configured to store hydraulic oil FL1 as a drive-side working fluid.
Further, the oil storage tank 10 is connected to a pump 11, a pressure regulator 12, and a control valve 13 through a sending drive pipe PL1c and a return drive pipe PL1d that constitute the drive pipe PL1.
The pump 11 sucks in the hydraulic oil FL1 in the oil storage tank 10, increases its pressure, and supplies it to the control valve 13 side through the feed side drive pipe PL1c.

The pressure regulator 12 is configured to adjust the hydraulic fluid FL1 so that it is not supplied to the control valve 13 side when the pressure of the hydraulic fluid FL1 is increased to a set value or higher by the pump 11.
For this reason, the pressure regulator 12 is installed so as to be able to bypass the sending drive pipe PL1c and the return drive pipe PL1d downstream of the pump 11.
Then, when the pressure of the hydraulic fluid FL1 exceeds a set value, the pressure regulator 12 bypasses the sending drive pipe PL1c and the return drive pipe PL1d downstream of the pump 11, and operates while releasing the pressure. Oil FL1 is collected into the oil storage tank 10.

The control valve 13 includes a pull side valve unit 13a and a push side valve unit 13b.
Note that the pull-side valve unit 13a and the push-side valve unit 13b are constructed from the same components. Therefore, the pull-side valve unit 13a and the push-side valve unit 13b will be collectively referred to as a valve unit 13U, and individual descriptions will be omitted.
The valve unit 13U includes a feed valve 131, a return valve 132, a throttle valve 133, and a check valve 134.

The feed valve 131 is constituted by an on-off valve, and its upstream end is connected to the downstream side of the pump 11 and the pressure regulator 12 in the feed drive piping PL1c.
Further, the downstream end of the feed valve 131 branches into three pipes, and one end of the return valve 132, one end of the throttle valve 133, and one end of the check valve 134 are connected to each of the three pipes. There is.

The return valve 132 is configured as an on-off valve, and the other end is connected to the return side drive pipe PL1d leading to the oil storage tank 10.
The other end of the throttle valve 133 and the other end of the check valve 134 are connected to one end of the pull side drive pipe PL1a or one end of the push side drive pipe PL1b while merging.
The other end of the pull-side drive pipe PL1a is connected to a drive pressure chamber 311 of a pull-side conversion unit 3a, which will be described later.

Next, the configuration of the driven section 2 will be explained (see FIG. 1).
The driven portion 2 is configured of a so-called double-acting cylinder that performs both the pushing operation and the retracting operation using the pressure of the working fluid.
The driven portion 2 includes a driven cylinder 21 (driven portion main body) and a driven piston 22 (driven body).
The driven cylinder 21 (driven part main body) is a hollow member having a cylindrical shape and closed at both ends.
Note that the internal space of the driven cylinder 21 is referred to as a driven part main body pressure chamber 211.

The driven piston 22 (driven body) divides the driven body pressure chamber 211 into two in the cylinder axis direction, and is arranged so as to be movable in the cylinder axis direction while maintaining close contact with the inner peripheral surface of the driven cylinder 21. ing.
Further, the driven piston 22 is integrally formed with a driven piston rod 23 made of a rod-shaped member.
The driven piston rod 23 extends in the axial direction of the driven cylinder 21 while passing through one end of the cylinder.

Regarding the driven part main body pressure chamber 211 divided into two by the driven piston 22, the space through which the driven piston rod 23 passes in the cylinder axis direction is defined as the pull side pressure chamber 21a, and the other space is defined as the push side pressure chamber 21b. do.
The pull-side pressure chamber 21a communicates with a driven pressure chamber 312 of the pull-side conversion unit 3a, which will be described later, via a pull-side driven pipe PL2a.
The push-side pressure chamber 21b communicates with a driven pressure chamber 312 of the push-side conversion unit 3b, which will be described later, via a push-side driven pipe PL2b.

In this embodiment, the movement of the driven piston 22 in the direction in which the driven piston rod 23 protrudes from the driven cylinder 21 (rightward in FIG. 1) is defined as a pushing operation.
Further, the movement of the driven piston 22 in the direction in which the driven piston rod 23 is sunk into the driven cylinder 21 (to the left in FIG. 1) is defined as a retraction operation.

Further, in this embodiment, a double-acting cylinder is used as the driven part 2, in which the driven piston 22 (driven body) linearly reciprocates along the cylinder axis direction by the pressure of the working water FL2. The present invention is not limited to such a configuration.
For example, it is possible to employ a rotary cylinder in which the driven member rotates around the cylinder axis due to the pressure of the working water FL2 as the driven part 2, and the same effects as the present embodiment can be obtained.

Next, the configuration of the converter 3 will be explained (see FIG. 1).
The converter 3 converts the pressure of the hydraulic fluid FL1 (driving side working fluid) supplied from the driving unit 1 to the converting unit 3 to the working water FL2 (driven side working fluid) supplied from the converting unit 3 to the driven unit 2. It is a structure for communicating.
The conversion unit 3 includes a pull side conversion unit 3a and a push side conversion unit 3b.
The pull-side conversion unit 3a is configured to supply working water FL2 to the pull-side pressure chamber 21a when the driven portion 2 performs a pull-in operation.

The push-side conversion unit 3b is configured to supply working water FL2 to the push-side pressure chamber 21b when the driven portion 2 performs a pushing operation.
Note that the pull-side conversion unit 3a and the push-side conversion unit 3b are composed of the same components. Therefore, the pull-side conversion unit 3a and the push-side conversion unit 3b will be collectively referred to as a conversion unit 3U for explanation, and individual explanations will be omitted.

The conversion unit 3U is composed of a double-acting cylinder including a conversion cylinder 31 (conversion unit main body) and a conversion piston 32 (displacement body).
The conversion cylinder 31 is a hollow member having a cylindrical shape and closed at both ends.

The conversion piston 32 (displacement body) divides the internal space of the conversion cylinder 31 into two in the cylinder axis direction, and is arranged so as to be movable in the cylinder axis direction while maintaining close contact with the inner peripheral surface of the conversion cylinder 31. ing.
Note that the internal space of the conversion cylinder 31 is referred to as a conversion pressure chamber 310. Regarding the conversion pressure chamber 310 divided into two by the conversion piston 32, a space communicating with the drive section 1 is defined as a drive pressure chamber 311, and a space communicating with the driven section 2 is defined as a driven pressure chamber 312.

The driving pressure chamber 311 is filled with hydraulic fluid FL1 (driving side working fluid), and the driven pressure chamber 312 is filled with working water FL2 (driven side working fluid).
When the pressure of the hydraulic fluid FL1 becomes higher than the pressure of the hydraulic fluid FL2, the conversion piston 32 moves toward the driven pressure chamber 312, and the hydraulic fluid FL2 is pushed out.
Further, when the pressure of the hydraulic fluid FL1 becomes lower than the pressure of the hydraulic fluid FL2, the conversion piston 32 moves toward the drive pressure chamber 311, and the hydraulic fluid FL1 is pushed out.

Note that if for some reason the seal between the piston outer periphery and the cylinder inner wall breaks and a seal failure occurs, the working fluid will not leak to the outside and will flow between the driving pressure chamber 311 and the driven pressure chamber 312. Then, it enters from the high pressure side to the low pressure side.
Therefore, the configuration of the conversion unit 3U of this embodiment is suitable when it is desired to avoid leakage of the working fluid to the outside, when it is desired not to contaminate the surrounding environment due to leakage of the working fluid, and so on.
Furthermore, since there is only one seal portion 34 that seals between the outer periphery of the piston and the inner wall of the cylinder, this is suitable when it is desired to simplify the structure and downsize the conversion unit 3U.

Furthermore, in the configuration of the conversion unit 3U of this embodiment, the relative pressures in the drive pressure chamber 311 and the driven pressure chamber 312 are switched between high pressure side and low pressure side in the extrusion operation and the retraction operation. Therefore, when a seal failure occurs in the seal portion 34, the working fluids are mixed in both the driving pressure chamber 311 and the driven pressure chamber 312.
Therefore, if a seal failure occurs in the seal portion 34, the hydraulic fluid FL1 is returned to the oil storage tank 10 with the hydraulic fluid FL2 mixed therein.
When the hydraulic fluid FL2 is mixed into the hydraulic fluid FL1, the hydraulic fluid FL1 becomes emulsified and changes such as becoming cloudy occur.
Thereby, a seal failure can be quickly detected even if the working fluid does not leak to the outside of the conversion unit 3U.

Next, the displacement detection means 4 will be explained (see FIG. 1).
The displacement detection means 4 is configured to measure the amount of displacement of the conversion piston 32.
As the displacement detection means 4, a pull-side displacement meter 4a that detects the amount of displacement of the pull-side conversion unit 3a and a push-side displacement meter 4b that detects the amount of displacement of the push-side conversion unit 3b are arranged.
In this embodiment, the pull-side displacement gauge 4a and the push-side displacement gauge 4b employ displacement gauges having the same configuration.
The displacement detection means 4 includes a conversion rod 41 and a potentiometer 42.
The conversion rod 41 is made of a rod-shaped member, and one end thereof is configured integrally with the conversion piston 32.

The conversion rod 41 is disposed so as to pass through one cylinder end of the driven cylinder 21 along the cylinder axis direction.
The other end of the conversion rod 41 is linked to a potentiometer 42 .
The potentiometer 42 is a sensor that electrically detects the position of the conversion rod 41 that is displaced together with the conversion piston 32.
In this embodiment, a combination of the conversion rod 41 and the potentiometer 42 is used as the displacement detection means 4, but the configuration is not limited to this.

For example, it is possible to configure the displacement detection means 4 so that the movement of the driven piston 22 (driven body) can be directly reproduced, and to operate the displacement detection means 4 while visually following the movement of the displacement detection means 4. .
In other words, any means that allows the operator to accurately measure and understand the function of the driven part 2, such as the position or displacement of the conversion piston 32, or the amount of movement of the working water FL2 (driven side working fluid), can be used as appropriate. It is possible to adopt.
By using such displacement detection means 4, water leakage from the driven pipe PL2 can be detected.

For example, the pump 11 is operated with the feed valve 131 of the pull-side valve unit 13a open, and the return valve 132 of the pull-side valve unit 13a, and the feed valve and return valve 132 of the push-side valve unit 13b closed.
In other words, the pull side driven pipe PL2a is pressurized while the push side conversion unit 3b and the push side displacement meter 4b are not operating and while confirming that the driven piston 22 is not moving.

In this state, if the pull-side displacement meter 4a does not detect the displacement of the pull-side conversion unit 3a, it is determined that there is no leakage of the working water FL2 (driven-side working fluid) from the pull-side driven pipe PL2a. can.
Further, when the pull-side displacement meter 4a detects the displacement of the pull-side conversion unit 3a, it is determined that the working water FL2 (driven-side working fluid) is leaking from somewhere in the pull-side driven pipe PL2a.

Next, while opening the feed valve 131 of the push side valve unit 13b, the pump 11 is operated with the return valve 132 of the push side valve unit 13b and the feed valve and return valve 132 of the pull side valve unit 13a closed. .
That is, with the pull side conversion unit 3a and the pull side displacement meter 4a not operating, the push side driven pipe PL2b is pressurized while confirming that the driven piston 22 is not moving.

In this state, if the push side displacement meter 4b does not detect the displacement of the push side conversion unit 3b, it is determined that there is no leakage of the working water FL2 (driven side working fluid) from the push side driven pipe PL2b. can.
Moreover, when the push side displacement meter 4b detects the displacement of the push side conversion unit 3b, it is determined that the working water FL2 (driven side working fluid) is leaking from somewhere in the push side driven pipe PL2b.
In addition to such water leak determination, by using the displacement detection means 4 of this embodiment, the expansion amount and pressure resistance performance of the driven pipe PL2 can be estimated during the operation of the fluid pressure actuator AC.

As an example, a case will be described in which the amount of expansion of the driven pipe PL2 during the retracting operation is estimated.
After the retraction operation starts, the amount of displacement of the conversion rod 41 of the pull side displacement meter 4a is measured from when the conversion rod 41 of the pull side displacement meter 4a starts moving until the conversion rod 41 of the push side displacement meter 4b starts moving. .
Then, from the measured displacement amount and the cross-sectional area of the conversion cylinder 31, the volume (expansion amount) of the driven pipe PL2 expanded by pressurization is calculated.
In addition, when the amount of expansion of the driven pipe PL2 is measured according to the above-mentioned procedure with no load applied to the driven part 2, this amount of expansion is the pressure loss that the driven system (driven pipe PL2, driven part 2) has. It can be estimated that

Next, the configuration of the absorption mechanism 5 will be explained (see FIG. 1).
The absorption mechanism 5 is configured to absorb a load when an excessive load such as an impact load is input due to the driven portion 2 colliding with a surrounding obstacle during driving work.
In this embodiment, an accumulator 51 is employed as the absorption mechanism 5.
The accumulator 51 is installed in a drive pipe PL1 (push-side drive pipe PL1b, pull-side drive pipe PL1a) that connects the drive unit 1 and the conversion unit 3 via an on-off valve 52.
The accumulator 51 is filled with compressible fluid such as air.

In this embodiment, the accumulator 51 is used as the absorption mechanism 5, but the accumulator 51 is not limited to this, and any structure that can absorb the load and prevent failure may be used as appropriate. can do. Therefore, another aspect of the absorption mechanism 5 will be described later.

Next, the configuration of the reservoir tank 6 will be explained (see FIG. 1).
The reservoir tank 6 is installed via an on-off valve 61 in the vicinity of the conversion section 3 of the driven pipe PL2 (push side driven pipe PL2b, pull side driven pipe PL2a) that connects the conversion section 3 and the driven section 2.
The reservoir tank 6 stores working water FL2. Further, if the working water FL2 leaks from the driven pipe PL2 and the driven part 2 for some reason, the working water FL2 stored in the reservoir tank 6 is supplied to the driven pipe PL2.
If the working water FL2 leaks, the amount stored in the reservoir tank 6 decreases, so by monitoring the amount stored in the reservoir tank 6, leakage of the working water FL2 can be detected.

Note that the fluid pressure actuator AC of this embodiment includes an absorption mechanism 5 and a reservoir tank 6, but these are components that are installed as necessary.
That is, even if one or both of them are not installed, they still function as actuators, and the operator can accurately measure and understand the movement of the driven part 2 using the displacement detection means 4.

Next, the pressure detection means 7 will be explained (see FIG. 1).
The pressure detection means 7 is configured to measure the pressure of the working water FL2 (driven side working fluid) in the driven pipe PL2. Further, the pressure detection means 7 includes a pull-side pressure gauge 7a that detects the pressure inside the pull-side driven pipe PL2a, and a push-side pressure gauge 7b that detects the pressure inside the push-side driven pipe PL2b.
In this embodiment, pressure gauges having the same configuration are employed as the pull-side pressure gauge 7a and the push-side pressure gauge 7b.

The difference between the pressure detected by the pull-side pressure gauge 7a and the pressure detected by the push-side pressure gauge 7b can be estimated to be the load applied to the driven part 2.
Furthermore, by being able to estimate the load applied to the driven part 2, it is possible to prevent failures and malfunctions due to excessive loads being applied to the fluid pressure actuator AC.

Next, the control section (not shown) will be explained.
The control unit (not shown) is configured to control the drive unit 1 so that the driven unit 2 operates according to an operating instruction from an operator.
The control unit opens and closes each valve constituting the control valve 13 and drives/stops the pump 11 while monitoring the displacement detection means 4 in accordance with the operating instructions of the operator.
Further, the control unit may be configured to open and close the on-off valve 52 of the accumulator 51 and the on-off valve 61 of the reservoir tank 6.

Next, the function of the fluid pressure actuator AC of this embodiment will be explained (see FIG. 1).
<Extrusion operation>
First, the control section closes the feed valve 131 and opens the return valve 132 for the pull-side valve unit 13a.
Furthermore, the control unit operates the pump 11 after opening the feed valve 131 and closing the return valve 132 for the push side valve unit 13b.
Next, in the drive unit 1, the pump 11 supplies the hydraulic oil FL1 from the oil storage tank 10 to the sending drive pipe PL1c.

The hydraulic oil FL1 supplied to the feed side drive pipe PL1c is introduced into the drive pressure chamber 311 of the push side conversion unit 3b via the feed valve 131 of the push side valve unit 13b, the check valve 134, and the push side drive pipe PL1b. be done.
Next, in the push side conversion unit 3b, the conversion piston 32 is moved toward the driven pressure chamber 312 side (rightward in FIG. 1) by the hydraulic oil FL1 introduced into the drive pressure chamber 311.
The moved conversion piston 32 pushes out the working water FL2 in the driven pressure chamber 312 to the push-side driven pipe PL2b.

Next, in the driven part 2, the working water FL2 pushed out from the driven pressure chamber 312 is introduced into the push side pressure chamber 21b via the push side driven pipe PL2b.
The driven piston 22 is moved in the direction in which the driven piston rod 23 protrudes from the driven cylinder 21 (to the right in FIG. 1) by the working water FL2 introduced into the push side pressure chamber 21b.
The moved driven piston 22 pushes out the working water FL2 in the pull-side pressure chamber 21a to the pull-side driven pipe PL2a.

The working water FL2 pushed out from the pull-side pressure chamber 21a is introduced into the driven pressure chamber 312 of the pull-side conversion unit 3a via the pull-side driven pipe PL2a.
Next, in the pull-side conversion unit 3a, the conversion piston 32 is moved toward the driving pressure chamber 311 (leftward in FIG. 1) by the working water FL2 introduced into the driven pressure chamber 312.
The moved conversion piston 32 pushes out the hydraulic fluid FL1 in the drive pressure chamber 311 to the pull side drive pipe PL1a.

Next, in the drive unit 1, the hydraulic fluid FL1 pushed out from the drive pressure chamber 311 of the pull side conversion unit 3a is supplied to the pull side valve unit 13a via the pull side drive pipe PL1a.
The hydraulic fluid FL1 supplied to the pull-side valve unit 13a passes through the throttle valve 133, the return valve 132, and is collected into the oil storage tank 10 through the return-side drive pipe PL1d.

<Retraction operation>
First, the control section opens the feed valve 131 and closes the return valve 132 for the pull-side valve unit 13a.
Furthermore, the control unit operates the pump 11 after closing the feed valve 131 and opening the return valve 132 for the push side valve unit 13b.
Next, in the drive unit 1, the pump 11 supplies the hydraulic oil FL1 from the oil storage tank 10 to the sending drive pipe PL1c.

The hydraulic oil FL1 supplied to the feed side drive pipe PL1c is introduced into the drive pressure chamber 311 of the pull side conversion unit 3a via the feed valve 131 of the pull side valve unit 13a, the check valve 134, and the pull side drive pipe PL1a. be done.
Next, in the pull-side conversion unit 3a, the conversion piston 32 is moved toward the driven pressure chamber 312 (rightward in FIG. 1) by the hydraulic oil FL1 introduced into the drive pressure chamber 311.
The moved conversion piston 32 pushes out the working water FL2 in the driven pressure chamber 312 to the pull-side driven pipe PL2a.

Next, in the driven part 2, the working water FL2 pushed out from the driven pressure chamber 312 is introduced into the pulled side pressure chamber 21a via the pulled side driven pipe PL2a.
The driven piston 22 is moved in the direction in which the driven piston rod 23 is sunk into the driven cylinder 21 (leftward in FIG. 1) by the working water FL2 introduced into the pull-side pressure chamber 21a.
By the moved driven piston 22, the working water FL2 in the push side pressure chamber 21b is pushed out to the push side driven pipe PL2b.

The working water FL2 pushed out from the push side pressure chamber 21b is introduced into the driven pressure chamber 312 of the push side conversion unit 3b via the push side driven pipe PL2b.
Next, in the push-side conversion unit 3b, the conversion piston 32 is moved toward the driving pressure chamber 311 (leftward in FIG. 1) by the working water FL2 introduced into the driven pressure chamber 312.
The moved conversion piston 32 pushes out the hydraulic fluid FL1 in the drive pressure chamber 311 to the push side drive pipe PL1b.

Next, in the drive unit 1, the hydraulic fluid FL1 pushed out from the drive pressure chamber 311 of the push side conversion unit 3b is supplied to the push side valve unit 13b via the push side drive pipe PL1b.
The hydraulic fluid FL1 supplied to the push-side valve unit 13b passes through the throttle valve 133, the return valve 132, and is collected into the oil storage tank 10 through the return-side drive pipe PL1d.

In addition, in the drive part 1, when the pump 11 is driven, it is conceivable that the pressure of the hydraulic oil FL1 in the sending side drive pipe PL1c increases to a set value or more for some reason.
In such a case, the pressure regulator 12 is activated, and the hydraulic fluid FL1 in the sending drive pipe PL1c is collected into the oil storage tank 10 through the return drive pipe PL1d.

Further, when adjusting the amount of extrusion and the amount of retraction, the position of the driven piston 22 (driven body) is calculated from the output of the displacement detection means 4.
Since the hydraulic fluid FL1 and the hydraulic fluid FL2 are incompressible fluids, the amount of displacement of the driven piston 22 can be calculated from the measurement results of the displacement detection means 4.

For example, regarding the displacement detection means 4, the position detected by the displacement detection means 4 in a stopped state before starting operation is defined as the reference position, the displacement of the conversion rod 41 in the right direction in FIG. 1 is defined as positive, and the displacement in the left direction is defined as negative. do.
When defined in this way, the sum of the displacement amount of the conversion rod 41 of the push side conversion unit 3b and the displacement amount of the conversion rod 41 of the pull side conversion unit 3a becomes zero.

This indicates that the working water FL2 is moving within the closed space without increasing or decreasing.
Therefore, when the sum of the displacement amount of the conversion rod 41 of the push side conversion unit 3b and the displacement amount of the conversion rod 41 of the pull side conversion unit 3a does not become zero, it can be determined that water leakage has occurred.
That is, by installing the displacement detection means 4 in both the pull side conversion unit 3a and the push side conversion unit 3b, it is possible to detect water leakage without installing the reservoir tank 6.

Next, the effects of the fluid pressure actuator AC of this embodiment will be explained.
In the fluid pressure actuator AC of this embodiment, a converting section 3 is arranged between a driving section 1 and a driven section 2.
The converting piston 32 (displacement body) is displaced within the converting pressure chamber 310 by the pressure of the hydraulic fluid FL1, thereby pushing out the working water FL2 (driven side working fluid) from the converting pressure chamber 310. .
Moreover, the working water FL2 (driven side working fluid) pushed out from the conversion pressure chamber 310 is supplied to the driven part 2, and is configured to displace the driven piston 22 (driven body).

That is, the conversion piston 32 (displacement body) and the driven piston 22 (driven body) are configured to move in conjunction with each other. Therefore, by measuring the displacement amount of the conversion piston 32 (displacement body) using the displacement detection means 4, the displacement amount of the driven piston 22 (driven body) can be calculated.
Therefore, the movement of the driven part 2 can be measured and grasped without installing any sensors on the driven part 2.
From the above, the fluid pressure actuator AC of this embodiment can be operated safely without malfunction even in situations where operation is required in harsh environments that are difficult for people to approach. Able to perform driving operations.

In the fluid pressure actuator AC of this embodiment, the driven portion 2 is constituted by a double-acting cylinder, and displacement detection means 4 are provided in both the pull-side conversion unit 3a and the push-side conversion unit 3b.
Thereby, it can be determined from the detection result that water is leaking from either the pull side driven pipe PL2a or the push side driven pipe PL2b.

The fluid pressure actuator AC of this embodiment employs a hydraulic device for the drive unit 1.
Since hydraulic equipment is generally widely used, high-performance equipment can be employed at low cost.

The fluid pressure actuator AC of this embodiment employs a hydraulic device that uses aqueous working water FL2 (driven side working fluid) in the driven part 2.
By employing a hydraulic device for the driven part 2, even if the working fluid leaks for some reason during operation, the impact on the surrounding environment can be kept to a smaller level.

The fluid pressure actuator AC of this embodiment includes an absorption mechanism 5 (accumulator 51) in a pipe for hydraulic oil FL1 (drive-side working fluid) that connects the drive unit 1 and the conversion unit 3.
Thereby, when an excessive load is applied to the driven piston 22 (driven member), the absorption mechanism 5 (accumulator 51) can absorb the excessive load and prevent the occurrence of problems.

<First alternative aspect>
Next, a first alternative aspect of this embodiment will be described (see FIGS. 2 and 3).
The difference between the first embodiment described above and this embodiment is the configuration of the absorption mechanism 5.
Note that since the components other than the absorption mechanism 5 are the same as those in the first embodiment, detailed explanations will be omitted.
The absorption mechanism 5 of this embodiment includes a pull-side absorption unit 5a, a push-side absorption unit 5b, and an absorption gas supply source 53 (see FIG. 2).

The pull-side absorption unit 5a protects each part of the fluid pressure actuator AC by absorbing the load input when the driven piston 22 (driven body) gets caught on a surrounding obstacle (not shown) during the pull-in operation. This is the configuration for
The push-side absorption unit 5b absorbs the load input when the driven piston 22 collides with a surrounding obstacle (not shown) during the pushing operation, and protects each part of the fluid pressure actuator AC. It is the composition.

Note that the pull-side absorption unit 5a and the push-side absorption unit 5b are composed of the same components. Therefore, the pull side absorption unit 5a and the push side absorption unit 5b will be collectively referred to as an absorption unit 5U and will be described, and individual explanations will be omitted.
The absorption unit 5U includes a double-acting cylinder having an absorption cylinder main body 54 and an absorption piston 55 (see FIG. 2).

The absorption cylinder main body 54 is a hollow member having a cylindrical shape and closed at both ends.
The absorption piston 55 divides the internal space of the absorption cylinder body 54 into two in the direction of the cylinder axis, and is arranged so as to be movable in the direction of the cylinder axis while maintaining close contact with the inner peripheral surface of the absorption cylinder body 54. .
Regarding the internal space of the absorption cylinder main body 54 divided into two by the absorption piston 55, the space communicating with the drive pipe PL1 is defined as an absorption hydraulic pressure chamber 541, and the space communicating with the absorption gas supply source 53 is defined as an absorption gas pressure chamber 542. .

The absorption liquid pressure chamber 541 is connected to the drive pipe PL1 through the absorption liquid pipe PL5a, and the absorption liquid pressure chamber 541 and the absorption liquid pipe PL5a are filled with hydraulic fluid FL1 (drive side working fluid). There is.
A liquid pipe opening/closing valve PL5b and a hydraulic pressure gauge PL5c are arranged in the absorption liquid pipe PL5a.
The liquid pipe opening/closing valve PL5b is configured to be able to open and close the pipe line of the absorption liquid pipe PL5a.
When the liquid pipe opening/closing valve PL5b is closed, the absorption liquid pipe PL5a is cut off, and the absorption unit 5U is separated from the drive pipe PL1.

If a load is input to the driven piston 22 (driven body) in this state, the function of absorbing the load of the absorption unit 5U is not exhibited.
When the liquid pipe opening/closing valve PL5b is open, the absorption liquid pipe PL5a is opened, and the absorption unit 5U is connected to the drive pipe PL1.
When a load is input to the driven piston 22 in this state, the function of absorbing the load of the absorption unit 5U is exhibited.
The hydraulic pressure gauge PL5c is configured to detect the pressure within the absorption hydraulic pressure chamber 541.

The absorption gas pressure chamber 542 is connected to the absorption gas supply source 53 through the absorption gas piping PL5d.
Further, the absorption gas pressure chamber 542 can be opened to the atmosphere through a gas release pipe PL5e.
The absorption gas pressure chamber 542 is filled with compressed air (compressible fluid).
A gas pressure regulator PL5f, a gas pipe opening/closing valve PL5g, and a gas pressure gauge PL5h are arranged in the absorption gas pipe PL5d.

The gas pressure regulator PL5f is configured to adjust the pressure of compressed air supplied from the absorption gas supply source 53 to the absorption gas pressure chamber 542 so that it does not exceed a set value.
The gas pipe opening/closing valve PL5g is configured to be able to open and close the pipe line of the absorption gas pipe PL5d.
When the gas piping opening/closing valve PL5g is closed, the pipe line leading from the absorption gas supply source 53 to the absorption gas pressure chamber 542 is shut off, and the supply of compressed air is stopped.
When the gas piping opening/closing valve PL5g is open, the pipe line leading from the absorption gas supply source 53 to the absorption gas pressure chamber 542 is opened, and compressed air is supplied.

The gas pressure gauge PL5h is configured to detect the pressure within the absorption gas pressure chamber 542.
A gas release valve PL5i is arranged in the gas release pipe PL5e.
The gas release valve PL5i is configured to be able to open and close the gas release pipe PL5e.
When the gas release valve PL5i is closed, the inside of the absorption gas pressure chamber 542 is cut off from the atmosphere.
When the gas release valve PL5i is open, the inside of the absorption gas pressure chamber 542 is opened to the atmosphere.

The absorption gas supply source 53 is configured to supply compressible fluid such as air to the pull side absorption unit 5a and the push side absorption unit 5b.
For example, if air is used as the medium for absorbing the input load, an air compressor can be used as the absorption gas supply source 53.
Furthermore, when a gas other than air, such as nitrogen gas, is used as a medium for absorbing the input load, it is possible to use a gas cylinder filled with the selected gas at high pressure.

In addition, in this embodiment, compressed air is supplied to both the pull-side absorption unit 5a and the push-side absorption unit 5b by one absorption gas supply source 53, but the structure is not limited to this. .
For example, an absorption gas supply source 53 may be installed for each of the pull-side absorption unit 5a and the push-side absorption unit 5b, and compressed air may be supplied to the pull-side absorption unit 5a and push-side absorption unit 5b individually.

Next, the function of the absorption mechanism 5 of this embodiment will be explained (see FIGS. 2 and 3).
When the absorption mechanism 5 is not to function, the liquid pipe on-off valve PL5b is closed, the gas pipe on-off valve PL5g is closed, and the gas release valve PL5i is opened.
When the absorption mechanism 5 is to function, the gas release valve PL5i is closed, the gas pressure regulator PL5f is set to a predetermined pressure, the gas pipe opening/closing valve PL5g is opened, and the liquid piping opening/closing valve PL5b is opened.

Also, when setting the pressure of the gas pressure regulator PL5f, the higher the set pressure value, the harder the absorption mechanism 5 will be against the input load, and the lower the set pressure value, the harder the absorption mechanism 5 will be against the input load. The absorption mechanism 5 becomes soft.
Regarding FIG. 3, the curve on the graph represents the amount of displacement of the absorption piston 55 due to the input load.
Moreover, each curve on the graph represents a difference in the set pressure value set by the gas pressure regulator PL5f. The higher the set pressure value, the greater the slope of the curve, and the lower the set pressure value, the smaller the slope of the curve.
When the absorption mechanism 5 is not operated, the slope of the curve becomes the largest, and the absorption mechanism 5 becomes the hardest with respect to the input load.

As described above, in the fluid pressure actuator AC of this embodiment, various forms of the absorption mechanism 5 can be employed, and the same effects as those of the first embodiment described above can be obtained.
In addition, in this embodiment, the absorption units 5U are arranged on each of the pulling side and the pushing side, but the invention is not limited to such a configuration.
For example, one absorption unit 5U is shared between the pull side and the push side, and is switched so that it is communicated with the push side drive pipe PL1b during a push operation, and communicated with the pull side drive pipe PL1a during a retraction operation. Is possible.
In this way, since the absorption mechanism 5 can be configured with one absorption unit 5U, the entire device can be made smaller, lighter, simpler, and lower in cost.

<Second alternative aspect>
Next, a second alternative aspect of this embodiment will be described (see FIG. 4 and FIGS. 5(a) to 5(c)).
In the first alternative embodiment described above, one absorption unit 5U is arranged on each of the push side and the pull side (see FIG. 3). On the other hand, the present embodiment differs in that two absorption units 5U are arranged on each of the push side and the pull side (see FIG. 4).
Note that since the components other than the absorption mechanism 5 are the same as those in the first embodiment, detailed explanations will be omitted.

The two absorption units 5U arranged on each of the pull side and the push side are composed of the same components, and are arranged in parallel to the drive pipe PL1.
Further, in the two absorption units 5U arranged on the pull side and push side, respectively, the set pressure values of the respective gas pressure regulators PL5f are set to different values.
By changing the set pressure value of the gas pressure regulator PL5f, the range of load that can be absorbed changes (see FIGS. 5(a) to 5(c)).
Note that XSt represents the maximum stroke amount when the absorption piston 55 moves within the absorption cylinder body 54, and XH represents the stroke amount required to absorb the load from the set pressure value PL to PH.

For example, if the set pressure value is small (PL), it is suitable for the purpose of absorbing shaking that repeats at a constant period, but it is not suitable for the purpose of absorbing large impact loads (Fig. 5(a)).
In addition, when the set pressure value is large (PH), it is suitable for the purpose of absorbing large impact loads, but is not suitable for the purpose of absorbing small shaking vibrations ( (See FIG. 5(b)).
Therefore, in this embodiment, two absorption units 5U set to different set pressure values are connected in parallel (see FIGS. 4 and 5(a) to (c)).

As described above, in the fluid pressure actuator AC of this embodiment, the two absorption units 5U constituting the absorption mechanism 5 are connected in parallel, so when an impact load is input from the outside, all the absorption units A load acts on 5U.
Then, the load in the range set according to each set pressure value is absorbed in order from the absorption unit 5U with the smallest set pressure value.

Thereby, the impact load can be absorbed over a wider range without performing a switching operation of the absorption unit 5U that absorbs the load according to the magnitude of the impact load input from the outside.
In addition, in this aspect, the absorbable load range can be expanded or reduced by increasing or decreasing the number of absorption units 5U of the same type, so it is possible to work with an absorption mechanism 5 that is more suited to the environment of the work site. can.

<Third alternative aspect>
Next, a third alternative aspect of this embodiment will be described (see FIG. 6(a)).
The difference between the first embodiment described above and this aspect is the configuration of the conversion section 3 (conversion unit 3U).
Note that the components other than the converter 3 are the same as those in the first embodiment, so detailed explanations will be omitted.

The conversion unit 3U of the first embodiment is constituted by a double-acting cylinder including one conversion piston 32 (displacement body) in the cylinder of one conversion cylinder 31 (conversion unit main body). The inside of the conversion cylinder 31 is divided into a driving pressure chamber 311 and a driven pressure chamber 312 by the conversion piston 32.

On the other hand, in the conversion unit 3U1 of this embodiment, the conversion piston 32 (displacement body) arranged inside the conversion cylinder 31 includes a driving side piston 32d and a driven side piston 32i.
The driving piston 32d and the driven piston 32i are integrally connected via a connecting shaft 33. The connecting shaft 33 is made of a rigid body such as a metal material that does not expand or contract, and defines a constant distance between the driving piston 32d and the driven piston 32i.

That is, the conversion piston 32 is displaced along the cylinder axis direction while keeping the volume of the detection chamber 313 constant.
Furthermore, a conversion rod 41 constituting the displacement detection means 4 is integrally provided on the connection shaft 33 .
The inside of the conversion cylinder 31 is divided into three chambers, a drive pressure chamber 311, a detection chamber 313, and a driven pressure chamber 312, by a drive side piston 32d and a driven side piston 32i that constitute the conversion piston 32.

The driving pressure chamber 311 is filled with hydraulic fluid FL1 (driving side working fluid), and the driven pressure chamber 312 is filled with working water FL2 (driven side working fluid).
Further, the detection chamber 313 communicates with the outside of the cylinder through a detection hole 314 that opens in the conversion cylinder 31.
The detection hole 314 has an elongated hole shape that extends in the cylinder axis direction while penetrating the cylinder wall of the conversion cylinder 31, and the conversion rod 41 passes through the detection hole 314.

Further, the detection hole 314 is set to a size that allows the conversion rod 41 to be smoothly displaced in the cylinder axis direction without rattling inside the detection hole 314.
In the conversion unit 3U1 of this embodiment, if a seal failure occurs between the outer periphery of the piston and the inner wall of the cylinder for some reason, the working fluid leaks into the detection chamber 313 and flows to the outside of the cylinder through the detection hole 314. be discharged.
Thereby, by examining the liquid leaked from the detection hole 314, it is possible to determine whether the seal failure is occurring on the drive side or the driven side.

Further, it is possible to prevent the working fluid on the high pressure side from being mixed into the working fluid on the low pressure side, which would occur due to a seal failure.
Therefore, maintenance work on the seal portion 34 can be performed without replacing the working fluid, so that the number of man-hours required for maintenance can be reduced and the operating cost can be reduced.
In other words, this structure is suitable when it is desired to promptly detect a seal failure while preventing leaked working fluid from mixing with the other working fluid.

Next, a fourth alternative aspect and a fifth alternative aspect of this embodiment will be described (see FIGS. 6(a) and (b)). The fourth alternative embodiment and the fifth alternative embodiment correspond to modifications of the third alternative embodiment described above.
Note that the components other than the converter 3 are the same as those in the first embodiment, so detailed explanations will be omitted.

<Fourth Alternative Aspect> (See Figure 6(b))
In the conversion unit 3U1 of the third different aspect, two conversion pistons 32 (a driving side piston 32d and a driven side piston 32i) are arranged in one conversion cylinder 31. These two conversion pistons 32 are integrally connected via a connecting shaft 33.

On the other hand, the conversion unit 3U2 of this embodiment includes two single-acting cylinders 35 (driving side conversion cylinder 31d, driven side conversion cylinder 31i) that are configured identically.
The hydraulic fluid FL1 is supplied to the driving pressure chamber 311 of the driving single-acting cylinder 35d, and the hydraulic fluid FL2 is supplied to the driven pressure chamber 312 of the driven single-acting cylinder 35i.
Further, the driving piston 32d and the driven piston 32i are arranged coaxially and integrally connected via a connecting shaft 33.
As a result, when the drive-side piston 32d slides in the direction in which the drive pressure chamber 311 expands, the driven-side piston 32i slides in the direction in which the driven pressure chamber 312 contracts.

Furthermore, when the drive-side piston 32d slides in the direction in which the drive pressure chamber 311 contracts, the driven-side piston 32i slides in the direction in which the driven pressure chamber 312 expands.
In other words, the configuration is similar to the configuration in which the conversion cylinder 31 of the third alternative embodiment described above is divided into two.
By adopting such a configuration, the same effects as the third alternative embodiment can be obtained, and the generally widely used single-acting cylinder can be used, reducing the manufacturing cost of the entire device. can do.

In this embodiment, the single-acting cylinder 35d on the driving side and the single-acting cylinder 35i on the driven side are configured to be the same, but the present invention is not limited to this.
For example, it is possible to use a cylinder having an inner diameter smaller than that of the driving single-acting cylinder 35d as the driven-side single-acting cylinder 35i.
In the case of such a configuration, the amount of displacement of the driven piston 22 of the driven portion 2 is smaller than the supply amount of the hydraulic fluid FL1 (drive-side working fluid).
Therefore, it is suitable when the driven piston 22 is required to move more precisely or move more slowly.

Further, it is possible to employ a cylinder having a larger inner diameter than the driving single-acting cylinder 35d as the driven-side single-acting cylinder 35i.
In the case of such a configuration, the amount of displacement of the driven piston 22 of the driven portion 2 becomes larger than the supply amount of the hydraulic fluid FL1 (drive-side working fluid).
Therefore, it is suitable when the driven piston 22 is required to have a larger movement and a faster movement.

As described above, since the driving side and the driven side are composed of separate single-acting cylinders, it is possible to replace at least one of the single-acting cylinders with a single-acting cylinder of a different size. becomes possible.
Then, by simply replacing one single-acting cylinder with a single-acting cylinder of another size, it is possible to change to a fluid pressure actuator AC with different characteristics.

<Fifth Alternative Aspect> (See Figure 6(c))
In the conversion unit 3U2 of the fourth alternative aspect, one conversion piston (drive side piston 32d, driven side piston 32i) is arranged in each of the two single-acting cylinders 35. These two conversion pistons 32 are integrally connected via a connecting shaft 33.

On the other hand, the conversion unit 3U3 of this embodiment includes two conversion cylinders 31 (drive side conversion cylinder 31d, driven side conversion cylinder 31i) and one conversion piston 32.
The hydraulic fluid FL1 is supplied to the driving pressure chamber 311 of the driving side conversion cylinder 31d, and the hydraulic fluid FL2 is supplied to the driven pressure chamber 312 of the driven side conversion cylinder 31i.
Note that the two conversion cylinders 31 have the same configuration.
The cross-sectional shape of the conversion piston 32 is set to such a size that it can slide smoothly along the cylinder axis direction on the inner circumferential surface of the conversion cylinder 31 without any gaps.

With such a configuration, the same effects as those of the third alternative aspect can be obtained, as well as the effects unique to this aspect.
In other words, since the entire outer circumferential surface of the conversion piston 32 comes into sliding contact with the entire inner circumferential surface of the conversion cylinder 31, when the conversion piston 32 reciprocates along the cylinder axis direction, it falls (tilts with respect to the cylinder axis direction). can be prevented.

This prevents the conversion piston 32 from biting or getting caught on the inner peripheral surface of the conversion cylinder 31.
Therefore, it is suitable when smoother and more precise movement of the conversion piston 32 is required.

<Second embodiment>
Next, a second embodiment will be described (see FIGS. 7 and 8).
Like the first embodiment, the fluid pressure actuator AC of this embodiment includes a driving section 1, a driven section 2, a converting section 3, a displacement detecting means 4, an absorption mechanism 5, a reservoir tank 6, and a control section (not shown). It is equipped with
The major difference between this embodiment and the first embodiment described above is that the driven part 2 is configured with a so-called single-acting cylinder that performs the pushing operation using the pressure of the working fluid and the retracting action using the repulsive force of a spring. The point is that there is.

Further, since a single-acting cylinder is adopted as the driven part 2, the driving part 1 and the converting part 3 do not include components on the pull side and are composed only of components on the push side.
Furthermore, the absorption mechanism 5 is comprised of components different from the accumulator 51 of the first embodiment and the absorption unit 5U of the first alternative embodiment.
Note that the configurations of the displacement detection means 4, the reservoir tank 6, and the control section (not shown) are configured in the same manner as in the first embodiment described above, so detailed explanations will be omitted.

In the drive unit 1, the configuration of the control valve 13 has been changed (see FIG. 7).
The control valve 13 of the first embodiment is configured to perform opening/closing operations for each valve on each of the sending side and the returning side (see FIG. 1).
On the other hand, the control valve 13 of the second embodiment is configured to be able to open and close the sending side and the returning side with a single operation.
In the driven portion 2, a pull side biasing spring 24 (biasing means) is housed in a compressed state in a pull side pressure chamber 21a.
The pull-side biasing spring 24 biases the driven piston 22 toward the push-side pressure chamber 21b by the compression reaction force.

The conversion unit 3 includes a push side conversion unit 3b, and the pull side conversion unit 3a is omitted.
Further, the driven pressure chamber 312 of the conversion cylinder 31 constituting the push side conversion unit 3b communicates with the push side driven pipe PL2b via the conversion side driven on-off valve v2 that opens and closes the pipe line.
The drive pressure chamber 311 of the conversion cylinder 31 constituting the push-side conversion unit 3b communicates with the push-side drive pipe PL1b without an on-off valve or the like, similar to the first alternative embodiment described above.

Note that the configuration of the push-side conversion unit 3b is comprised of the same components as the conversion unit 3U of the first embodiment, so a detailed explanation will be omitted.
The absorption mechanism 5 includes an absorption unit 5U and an absorption gas supply source 53.
Note that the absorbing gas supply source 53 has the same configuration as the first alternative embodiment described above, so a detailed explanation will be omitted.
The absorption unit 5U includes a cylinder having an absorption cylinder main body 54, a driving side absorption piston 551, and a driven side absorption piston 552.

The absorption cylinder main body 54 is a hollow member having a cylindrical shape and closed at both ends.
The driving-side absorption piston 551 and the driven-side absorption piston 552 each divide the internal space of the absorption cylinder body 54 in the direction of the cylinder axis, and while maintaining close contact with the inner peripheral surface of the absorption cylinder body 54, the cylinder axis It is arranged so that it can be moved in the direction.
That is, the internal space of the absorption cylinder main body 54 is divided into three parts in the cylinder axis direction by the driving side absorption piston 551 and the driven side absorption piston 552.

The internal space of the absorption cylinder main body 54 divided into three parts is divided by the drive-side absorption piston 551, and is located on one end side in the cylinder axis direction, and is connected to the push-side drive pipe PL1b through the absorption-side drive pipe PL5j. is defined as the drive-side absorption pressure chamber 543. Further, a space divided by the driven side absorption piston 552, located on the other end side in the cylinder axis direction, and connected to the push side driven pipe PL2b through the absorption side driven pipe PL5k is defined as a driven side absorption pressure chamber 544. . Furthermore, a space formed between the driving side absorption piston 551 and the driven side absorption piston 552 and connected to the absorption gas supply source 53 through the absorption gas piping PL5d is defined as an absorption gas pressure chamber 542.

The absorption-side drive pipe PL5j is connected at one end to the drive-side absorption pressure chamber 543 and at the other end to the push-side drive pipe PL1b, and is provided with an absorption-side drive on-off valve v1 that opens and closes the pipe.
The absorption-side driven pipe PL5k is connected at one end to the driven-side absorption pressure chamber 544 and at the other end to the push-side driven pipe PL2b, and is provided with an absorption-side driven on-off valve v3 that opens and closes the pipe.
One end of the absorption gas pipe PL5d is connected to the absorption gas pressure chamber 542, and the other end is bifurcated.

One of the bifurcated pipes is connected to the absorption gas supply source 53, and a gas pipe opening/closing valve v4 for opening and closing the pipe is installed between the branch part and the absorption gas supply source 53. .
Further, the other branched pipe line is opened to the atmosphere, and a gas release valve v5 for opening and closing the pipe line is installed.
In this embodiment, there are three types of on-off patterns depending on the opening/closing patterns of five on-off valves (absorption-side driven on-off valve v1, conversion-side driven on-off valve v2, absorption-side driven on-off valve v3, gas piping on-off valve v4, and gas release valve v5). It is possible to use different operation modes (hard operation, soft operation, gas pressure operation) (see Fig. 8).

Next, each operation mode will be explained.
<Hard operation> (See Figures 7 and 8 No.1 and No.2)
Hard operation is suitable for operating modes that require high precision in the movement of the driven part 2, such as repeating the same operation in automatic operation, and operating modes where there is no risk of inputting an external impact load.
When performing hard operation (see No. 1 in FIGS. 7 and 8), the absorption side drive on-off valve v1 is closed, the conversion side driven on-off valve v2 is opened, and the absorption side driven on-off valve v3 is closed.
Therefore, during driving operation, the hydraulic fluid FL1 and the hydraulic water FL2 do not flow into the driving side absorption pressure chamber 543 and the driven side absorption pressure chamber 544.

As a result, in a hard operation, the hydraulic oil FL1 (driving side working fluid) and the working water FL2 (driven side working fluid), which are incompressible fluids, act as media for transmitting force, resulting in a hard operation.
Note that as long as the gas piping opening/closing valve v4 and the gas release valve v5 do not open at the same time, there is no particular problem in which one opens and which one closes.
When stationary due to hard operation (see FIGS. 7 and 8 No. 2), the absorption side drive on-off valve v1 is closed, the conversion side driven on-off valve v2 is closed, and the absorption side driven on-off valve v3 is closed. Note that as long as the gas piping opening/closing valve v4 and the gas release valve v5 do not open at the same time, there is no particular problem in which one opens and which one closes.

<Flexible operation> (See Figure 7, Figure 8 No. 3 to No. 6)
Although soft operation is not as effective as hard operation, it is suitable in cases where relatively high precision is required in the movement of the driven portion 2 and absorption of externally input impact loads is required.
When performing flexible operation (see Figures 7 and 8 No. 3), close the absorption side drive on-off valve v1, open the conversion side driven on-off valve v2, open the absorption side driven on-off valve v3, and open the gas piping on-off valve. Close v4 and close gas release valve v5.
Therefore, during operation, the working water FL2 can flow into the driven-side absorption pressure chamber 544, and air as an absorption gas is sealed in the absorption gas pressure chamber 542.
In the flexible operation, hydraulic oil FL1 (driving side working fluid) and working water FL2 (driven side working fluid), which are incompressible fluids, act as media for transmitting force.

Furthermore, in the flexible operation, air, which is a compressible fluid, acts as a medium (absorbing gas) that absorbs the impact load input from the outside.
Due to these, when a load is input from the outside to the driven piston 22 (driven body) during soft operation, the load is transmitted to the air sealed in the absorption gas pressure chamber 542 through the working water FL2. The input load is then absorbed by the air sealed within the absorption gas pressure chamber 542.
When it is stationary by flexible operation (see Figures 7 and 8 No. 4), the absorption side drive on-off valve v1 is closed, the conversion side driven on-off valve v2 is closed, the absorption side driven on-off valve v3 is opened, and the gas piping is opened and closed. Close valve v4 and close gas release valve v5.

Note that in order to perform the soft operation, the initial volume or initial pressure within the absorbing gas pressure chamber 542 must be set before starting the operation.
The method of setting the initial volume and then performing the soft operation is suitable when absorbing the load softly is prioritized over ensuring a stroke length when absorbing the load.
When setting the initial volume (see Figures 7 and 8 No. 5), open the absorption side drive on-off valve v1, close the conversion side driven on-off valve v2, close the absorption side driven on-off valve v3, and open/close the gas piping. Close valve v4 and open gas release valve v5. After setting the initial volume, the absorption side drive on-off valve v1 and the gas release valve v5 are closed.

The method of setting the initial pressure and then performing soft operation (see Figures 7 and 8 No. 6) is to shorten the stroke length when absorbing the load, rather than absorbing the load softly. This is suitable when you want to give priority to performing the process quickly.
When setting the initial pressure (see Figures 7 and 8 No. 6), close the absorption side drive on-off valve v1, close the conversion side driven on-off valve v2, close the absorption side driven on-off valve v3, and open/close the gas piping. Open valve v4 and close gas release valve v5. Then, after setting the initial pressure, the gas pipe opening/closing valve v4 is closed.

<Gas pressure operation> (See Figure 7, Figure 8 No.7)
Gas pressure operation is suitable for cases where the degree of force is given priority over the precision of movement, such as when grasping a soft object without crushing it.
Gas pressure operation uses air, which is a compressible fluid, as a medium for transmitting force and as a medium (absorbing gas) for absorbing shock loads input from the outside.

When performing gas pressure operation (see FIGS. 7 and 8 No. 7), the absorption side drive on-off valve v1 is closed, the conversion side driven on-off valve v2 is closed, and the absorption side driven on-off valve v3 is opened.
When pressurizing the absorption gas pressure chamber 542 (pushing operation of the driven section 2), the gas pipe opening/closing valve v4 is opened and the gas release valve v5 is closed.
Moreover, when depressurizing the absorption gas pressure chamber 542 (retracting operation of the driven part 2), the gas piping opening/closing valve v4 is closed and the gas release valve v5 is opened.

When stationary due to gas pressure operation, close the absorption side drive on-off valve v1, close the conversion side driven on-off valve v2, open the absorption side driven on-off valve v3, close the gas piping on-off valve v4, and open the gas release valve v5. close.
In other words, when it comes to rest with gas pressure operation, the opening and closing pattern is the same as when it comes to rest with soft operation (see Figures 7 and 8 No. 4).

Next, the effects of the fluid pressure actuator AC of this embodiment will be explained.
In the fluid pressure actuator AC of this embodiment, the driven part 2 is a single-acting type in which the pushing operation is performed by the pressure of the working water FL2, and the retracting action is performed by the compression reaction force of the pulling side biasing spring 24 (biasing means). It consists of a cylinder.
Since the driven part 2 is configured with a single-acting cylinder, the driving part 1, the converting part 3, etc. are configured only with push-side components, with pull-side components omitted.
Further, the displacement detection means 4 is configured similarly to the first embodiment and measures the amount of displacement of the conversion piston 32 (displacement body) of the push side conversion unit 3b.

As a result, the fluid pressure actuator AC of this embodiment can accurately detect the movement of the driven piston 22 of the driven part 2 without installing sensors around the driven piston 22 for a single-acting cylinder. can.
Further, a reservoir tank 6 is installed in the push-side driven pipe PL2b as in the first embodiment, and leakage of the working water FL2 can be detected by detecting a decrease in the amount of water stored in the reservoir tank 6. can.

The absorption mechanism 5 of this embodiment is configured such that one absorption unit 5U can absorb impact loads input from the outside in both directions of the extrusion operation and the retraction operation direction.
This simplifies the entire device, making it possible to reduce the size and cost.
Furthermore, in the absorption mechanism 5 of this embodiment, one absorption unit 5U can use three types of operation modes (hard operation, soft operation, and gas pressure operation) depending on the opening/closing pattern of the on-off valve.
This simplifies the entire device, making it possible to achieve a more versatile fluid pressure actuator AC while reducing the size and cost.

From the above, the fluid pressure actuator AC of the present invention can be used in harsh environments around the driven piston 22 (driven body), regardless of whether it is a double-acting cylinder (first embodiment) or a single-acting cylinder (second embodiment). The movement of the driven piston 22 can be accurately detected without installing sensors in the environment.
This allows the operator to operate the fluid pressure actuator AC in a safe location while accurately grasping the movement of the driven piston 22 at hand.

AC fluid pressure actuator 1 Drive section 2 Driven section 21 Driven cylinder (driven section main body)
211 Driven part main body pressure chamber 22 Driven piston (driven body)
24 Pull side biasing spring (biasing means)
3 Conversion section 3U Conversion unit 31 Conversion cylinder (conversion unit main body)
310 Conversion pressure chamber 311 Drive pressure chamber 312 Driven pressure chamber 32 Conversion piston (displacement body)
4 Displacement detection means 5 Absorption mechanism FL1 Hydraulic oil (drive side working fluid)
FL2 Working water (driven side working fluid)
PL1 Drive piping PL2 Driven piping

Claims (4)

The conversion pressure chamber formed inside the conversion unit body,
a drive pressure chamber in which a drive-side working fluid made of incompressible fluid can be supplied and discharged through drive piping;
While the driven side working fluid consisting of an incompressible fluid is divided into a driven pressure chamber that can be supplied and discharged through driven piping,
comprising a displacement body disposed so as to be displaceable within the conversion pressure chamber;
When either the driving side working fluid or the driven side working fluid is supplied to the conversion pressure chamber, the displacement body is displaced according to the supplied amount,
a pull-side conversion unit configured with a conversion unit in which the other of the driving-side working fluid and the driven-side working fluid is discharged from the conversion pressure chamber;
a push-side conversion unit configured with the conversion unit;
a conversion unit comprising;
a detection means for measuring the amount of displacement of the displacement body;
a drive unit that supplies the drive-side working fluid to the drive pipe;
A driven part body pressure chamber formed inside the driven part main body is divided into a pull side pressure chamber and a push side pressure chamber, and the driven part is provided with a driven body disposed so as to be displaceable within the driven part main body pressure chamber. Department and
The internal space formed inside the absorption cylinder body,
an absorption hydraulic pressure chamber to which the drive-side working fluid can be supplied and discharged through the drive piping;
It is divided into an absorption gas pressure chamber and an absorption gas pressure chamber where compressible gas set at a predetermined pressure can be supplied and discharged.
an absorption piston disposed displaceably within the absorption cylinder body;
a pull-side absorption unit configured with an absorption unit that absorbs the load by displacing the absorption piston according to the load when an excessive load is input to the drive-side working fluid;
a push-side absorption unit configured with the absorption unit;
an absorption mechanism comprising;
Equipped with
The pull side conversion unit is
The driven pressure chamber communicates with the pull-side pressure chamber through the driven pipe,
The drive pressure chamber communicates with the absorption liquid pressure chamber of the pull-side absorption unit through an absorption liquid pipe that communicates with the drive pipe,
The push side conversion unit is
The driven pressure chamber communicates with the push side pressure chamber through the driven pipe,
A fluid pressure actuator characterized in that the drive pressure chamber communicates with the absorption liquid pressure chamber of the push-side absorption unit through an absorption liquid pipe that communicates with the drive pipe.
The fluid pressure actuator according to claim 1 ,
The displacement body is
The conversion pressure chamber is divided into the drive pressure chamber, the detection chamber, and the driven pressure chamber, including a drive side piston and a driven side piston that is displaced integrally with the drive side piston via a connecting shaft. death,
The detection means includes:
comprising a conversion rod that is displaced integrally with the displacement body while passing through a detection hole opened in the wall of the detection chamber;
A fluid pressure actuator that measures the amount of displacement of the conversion rod.
The fluid pressure actuator according to claim 1 ,
The conversion unit main body is
a drive-side conversion cylinder having the drive pressure chamber inside;
and a driven side conversion cylinder having the driven pressure chamber inside,
The displacement body is
a drive side piston formed at one end of the connecting shaft and disposed so as to be displaceable within the drive pressure chamber;
a driven side piston formed at the other end of the connection shaft and disposed so as to be displaceable within the driven pressure chamber;
The detection means includes:
comprising a conversion rod that is displaced integrally with the displacement body,
A fluid pressure actuator that measures the amount of displacement of the conversion rod.
The fluid pressure actuator according to claim 1 ,
The conversion unit main body is
a drive-side conversion cylinder having the drive pressure chamber inside;
The driven pressure chamber is provided inside the driven side conversion cylinder and the driven side conversion cylinder is set to have the same diameter as the drive side conversion cylinder,
The displacement body is
one end side is disposed so as to be displaceable within the drive pressure chamber,
the other end side is disposed so as to be displaceable within the driven pressure chamber;
The entire outer peripheral surface is in sliding contact with the entire inner peripheral surface of the driving side conversion cylinder and the entire inner peripheral surface of the driven side conversion cylinder,
The detection means includes:
comprising a conversion rod that is displaced integrally with the displacement body,
A fluid pressure actuator that measures the amount of displacement of the conversion rod.

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