JP2021014888A - Fluid pressure actuator - Google Patents

Abstract

To provide a fluid pressure actuator which can simultaneously and easily take out rotation torque from a rotating shaft, and a linear reciprocation drive force from a piston rod.SOLUTION: A fluid pressure actuator is constituted of two rod cylinders 11 and a linear-motion/rotation conversion device 12. A piston rod 25 is non-rotatably regulated in a peripheral direction with respect to a cylinder tube 21, and the linear-motion/rotation conversion device 12 has a female screw 31 attached to an end part of an insertion hole 25a of the piston rod, a rotating shaft 32 having a male screw screwed with the female screw 31, and arranged so as to be capable of intruding into the insertion hole, and a shaft support part 33 for rotatably and immovably supporting the rotating shaft 32 in an axial direction. The piston rod 25 moves in the axial direction accompanied by the movement of the piston 24 in the axial direction in a state that the piston rod penetrates a first cover 22 and the second cover 23, and the rotating shaft 32 rotates by the screwing of the female screw 31 and the male screw.SELECTED DRAWING: Figure 5

Description

The present invention relates to a fluid pressure actuator that converts linear reciprocating drive by fluid pressure into rotary drive.

Conventionally, fluid pressure actuators that convert linear reciprocating drive by fluid pressure into rotary drive (swing drive) have been used in civil engineering construction machines, transportation machines, precision machines, and various other industrial machines.

As a conventional fluid pressure actuator of this type, there is a type in which a rack is linearly reciprocated by a fluid pressure cylinder and converted into a rotary drive by a pinion. However, this type has a drawback that the total length due to the fluid pressure cylinder and the rack becomes long and the size becomes large.

In addition, a fluid pressure actuator is proposed as a cylinder device in which a ball screw mechanism is internally installed in the piston of a fluid pressure cylinder, the linear reciprocating motion of the piston is converted into the rotational motion of a screw rod screwed with the ball screw mechanism, and the piston is taken out as rotational torque. (Patent Document 1).

Further, a hydraulic actuator has been proposed that converts a linear reciprocating motion of a piston housed in a casing into a swing motion which is a rotation of forward / reverse switching of a shaft (Patent Document 2).

Japanese Unexamined Patent Publication No. 2008-2593 JP-A-2009-41726

However, in the fluid pressure actuators of Patent Documents 1 and 2 described above, the linear reciprocating motion due to the fluid pressure can be converted into the rotational motion to obtain the rotational torque, but the linear reciprocating driving force is taken out at the same time as the rotational torque. I couldn't.

Therefore, for example, in the handling of a transport member, when the transport member is rotated and moved, two drive means of a fluid pressure actuator that outputs a rotational torque and a fluid pressure cylinder that outputs a linear reciprocating driving force are required.

Further, when the conventional fluid pressure actuator is used, if the rotational torque is temporarily insufficient, the predetermined rotational operation may not be performed. In such a case, the fluid pressure is increased within the rated pressure range, or the fluid pressure actuator is replaced with a fluid pressure actuator having a larger driving force, which is troublesome to deal with and work, and is extremely difficult in reality.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a fluid pressure actuator capable of easily extracting a rotational torque from a rotating shaft and a linear reciprocating driving force from a piston rod at the same time. ..

The fluid pressure actuator according to the embodiment of the present invention closes the cylinder tube, the first cover fixed to the cylinder tube so as to close one end surface of the cylinder tube, and the other end face of the cylinder tube. A second cover fixed to the cylinder tube, a piston slidable in the axial direction along the inner peripheral surface of the cylinder tube, and an axial insertion hole are provided in the center of the piston. A piston rod that is integrally connected to the cylinder tube, slides through the first cover and the second cover in the axial direction, and is restricted from rotating in the circumferential direction with respect to the cylinder tube, and the piston rod. A female screw attached to the end of the insertion hole of the piston rod, a rotating shaft having a male screw screwed into the female screw and arranged so as to be able to enter the insertion hole, and the cylinder tube. A shaft support portion which is fixedly provided to support the rotating shaft so as to be rotatable and non-movable in the axial direction is provided, and the piston rod becomes the first piston rod with the axial movement of the piston. It is configured to move in the axial direction while penetrating the cover and the second cover, and to rotate the rotating shaft by screwing the female screw and the male screw.

Preferably, an engaging portion for transmitting an axial driving force to the load is provided at an end portion of the piston rod opposite to the side to which the female screw is attached.

Further, the piston rod is regulated to be non-rotatable by being provided at a position eccentric from the center position of the cylinder tube.

Further, the shaft support portion is attached to a bracket fixed to the outer end surface of the first cover or the second cover. The bracket has a cylindrical portion, a flange-shaped portion provided at the base end portion of the cylindrical portion, and a bottom portion provided at the tip end portion of the cylindrical portion, and the flange-shaped portion is the first. It is fixed to the outer end surface of the cover or the second cover, and the shaft support portion is attached to the bottom portion. The outer shape of the cylindrical portion may be smaller than the outer shape of the cylinder tube.

Further, both rod cylinders are composed of the cylinder tube, the first cover, the second cover, the piston, and the piston rod, and the female screw, the rotating shaft, and the shaft support portion linearly and rotate. A conversion device is configured, and the female screw is inserted into the insertion hole at the end of the insertion hole of the piston rod.

According to the present invention, the rotational torque from the rotating shaft and the linear reciprocating driving force from the piston rod can be easily taken out at the same time.

It is a perspective view which shows the appearance of the fluid pressure actuator which concerns on one Embodiment of this invention. It is a top view of the fluid pressure actuator which concerns on one Embodiment of this invention. It is a right side view of the fluid pressure actuator of FIG. It is a left side view of the fluid pressure actuator of FIG. FIG. 2 is a cross-sectional view taken along the line AA of the fluid pressure actuator of FIG. It is sectional drawing which shows the other embodiment of the shape of the end part of a piston rod. It is sectional drawing of the fluid pressure actuator which concerns on other embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

1 is a perspective view showing an overview of the fluid pressure actuator 1 according to the embodiment of the present invention, FIG. 2 is a plan view of the fluid pressure actuator 1, FIG. 3 is a right side view of the fluid pressure actuator 1, and FIG. 4 is a fluid pressure. The left side surface of the actuator 1, FIG. 5 is a cross-sectional view taken along the line AA of the fluid pressure actuator 1 of FIG. 2, and FIG. 6 is a cross-sectional view showing another embodiment of the shape of the end portion of the piston rod 25.

Since FIG. 1 shows an overview of the fluid pressure actuator 1, there are some parts that do not match the shape of the fluid pressure actuator 1 shown in FIGS. 2 to 5.

In FIG. 1, the fluid pressure actuator 1 includes both rod cylinders 11 and a linear / rotational conversion device 12.

With reference to FIGS. 1 to 5, both rod cylinders 11 include a cylinder tube 21, a first cover 22, a second cover 23, a piston 24, a piston rod 25, and the like.

The cylinder tube 21 is a cylindrical tube made of a metal material such as a steel material, an aluminum alloy, or another alloy. It may be made of a material such as ceramics or plastic.

The first cover 22 is fixed by a plurality of bolts 22a so as to close one end face of the cylinder tube 21, and the second cover 23 is fixed by a plurality of bolts 23a so as to close the other end face of the cylinder tube 21. Is fixed by.

Ports PA and PB are provided on the first cover 22 and the second cover 23, and by supplying the pressure fluid from the ports PA and PB, the pressure fluid is supplied to the cylinder chamber CA inside the cylinder tube 21. It flows into the CB.

The first cover 22 and the second cover 23 are provided with holes for the piston rod 25 to penetrate, and packings 22b and 23b are provided on the inner peripheral surfaces thereof, respectively.

The piston 24 is axially slidable along the inner peripheral surface of the cylinder tube 21. A packing 24a is provided on the outer peripheral surface of the piston 24 to seal the piston 24 with the inner peripheral surface of the cylinder tube 21.

The piston rod 25 is provided with an axial insertion hole 25a in the central portion, and is hollow over the entire length thereof. The piston rod 25 is integrally connected to the piston 24. That is, the piston rod 25 is formed integrally with the piston 24, or is formed separately and then connected so as to be integrated.

The piston rod 25 slides through the first cover 22 and the second cover 23 in the axial direction, and is between them by packings 22b and 23b provided on the first cover 22 and the second cover 23. Is sealed.

The piston rod 25 is regulated so that it cannot rotate in the circumferential direction with respect to the cylinder tube 21. That is, the piston rod 25 and the piston 24 integrated with the piston rod 25 can move in the axial direction with respect to the cylinder tube 21, but cannot rotate in the circumferential direction.

In the embodiments shown in FIGS. 1 to 5, the piston rod 25 is provided so that the center position 25CT is located eccentric from the center position 21CT of the cylinder tube 21 by a distance L1. By eccentricizing the piston rod 25 with respect to the cylinder tube 21 in this way, it is possible to obtain a detent function without increasing the number of parts.

However, in addition to this, for example, the piston rod 25 may be regulated so as to be non-rotatable by making its outer cross section a polygon such as a quadrangle or a hexagon. Further, the external cross section of the piston 24 may be regulated to be non-rotatable by forming an oval shape such as an egg shape or an elliptical shape.

The ends 25b and c of the piston rod 25 may be provided with engaging portions for driving an external load in the axial direction. For example, a screw may be provided on the outer peripheral surface of the end portions 25b, c, a screw may be provided on the inner peripheral surface of the end portion 25c, or a hole penetrating in the radial direction may be provided. Further, a cover for closing the end surface of the end portion 25c may be provided, a screw hole or the like may be provided in the cover, and a hook or the like may be provided here.

Further, as shown in FIG. 6, the insertion hole 25Ba provided in the piston rod 25 may be formed so as to have a shape in which the insertion hole 25Ba is closed at the end portion 25Bc without making the total length of the piston rod 25. Then, for example, the screw shaft portion 25Bd for connecting to the load may be provided at the end portion 25Bc. Alternatively, a screw hole may be provided instead of the screw shaft portion 25Bd.

In this way, it becomes easy to connect with the load for transmitting the linear reciprocating driving force.

Both rod cylinders 11 are attached by brackets 27a and 27b between the first cover 22 and the second cover 23 and the pedestal 26 in a state where the cylinder tube 21 is placed on the flat plate-shaped pedestal 26. , Is fixed.

In both rod cylinders 11, the piston rod 25 always protrudes from the outer end faces of the first cover 22 and the second cover 23, and the piston rod 25 shafts by alternately supplying the pressure fluid from the port PA or PB. It drives linearly back and forth in the direction.

Next, the straight line / rotation conversion device 12 includes a female screw 31, a rotation shaft 32, a shaft support portion 33, and the like.

The female screw 31 is a nut of a ball screw and includes a circulating ball 31BL. The main body of the female screw 31 is inserted into the inside from the end portion 25b on the side of the first cover 22 of the insertion hole 25a of the piston rod 25, and the flange portion 31a provided on the outside of the female screw 31 is the piston rod 25. The bolt 31b is attached to the piston rod 25 by being screwed into the screw hole provided in the end portion 25b in a state of being in contact with the end portion 25b.

The rotating shaft 32 is a screw shaft that is screwed into the female screw 31 via the ball 31BL. That is, the ball screw is composed of the female screw 31, the ball 31BL, and the rotating shaft 32. The axis of the rotating shaft 32 coincides with the axis of the piston rod 25, and is arranged so as to be able to enter the insertion hole 25a as the piston rod 25 moves in the axial direction.

The rotating shaft 32 has a screw portion 32a having a screw on the outer circumference, a columnar shaft portion 32b having no screw, a small diameter portion 32c having a smaller diameter than the columnar shaft portion 32b, and a small diameter portion 32c. It has an output shaft portion 32d at the tip of the. The axial length of the screw portion 32a is set to be longer than the stroke length of the piston rod 25. A key groove is provided in the output shaft portion 32d, and a key 35 for transmitting rotational torque to an external load is mounted therein.

A bearing 33b is fitted into the inner peripheral surface of the recess of the main body housing 33a of the shaft support portion 33, and a cover 33c is attached to the end surface thereof. The main body housing 33a is fixed to the bracket 34 by bolts 33d, and the cover 33c is fixed to the main body housing 33a by bolts 33e.

The bracket 34 is fixed to the pedestal 26 by bolts 34a.

The small diameter portion 32c of the rotating shaft 32 is fitted into the inner peripheral surface of the bearing 33b, and the stepped portion of the columnar shaft portion 32b and the small diameter portion 32c is in contact with the end surface of the bearing 33b. It is supported so that it can rotate and cannot move in the axial direction.

Next, the operation of the fluid pressure actuator 1 will be described.

The fluid pressure actuator 1 moves in the axial direction with the piston rod 25 penetrating the first cover 22 and the second cover 23 as the piston 24 moves in the axial direction, and the rotating shaft 32 rotates.

That is, when the piston rods 25 of both rod cylinders 11 are linearly reciprocated, the linear motion of the female screw 31 accompanying this is converted into the rotary motion of the rotary shaft 32, and is taken out as a rotary torque from the output shaft portion 32d.

Further, since the piston rod 25 is linearly reciprocated, the load can be linearly reciprocated by connecting the load to the piston rod 25.

That is, the rotational torque from the rotary shaft 32 and the linear reciprocating driving force from the piston rod 25 can be easily extracted at the same time.

In this way, the fluid pressure actuator 1 can simultaneously take out the rotational torque and the linear reciprocating driving force. Therefore, for example, when a load such as a transport member is rotated and moved, one fluid pressure is used as the driving means. It can be configured using only the actuator 1.

Further, when the fluid pressure actuator 1 is used, if the rotational torque is insufficient from the output shaft portion 32d, the outer end portion 25c of the piston rod 25 is pushed, or the hook attached to the end portion 25c is pulled. The rotational torque can be increased. Therefore, by separately preparing a standard fluid pressure cylinder and appropriately processing the end portion 25c of the piston rod 25, it is possible to easily cope with a shortage of rotational torque.

On the contrary, when the linear reciprocating driving force of the piston rod 25 is insufficient, the linear reciprocating driving force can be increased by applying a rotational torque to the rotating shaft 32 from the outside.

That is, the fluid pressure actuator 1 can mutually convert and complement the linear reciprocating driving force and the rotational torque.

Further, by connecting a generator or the like to the rotating shaft 32, it is possible to obtain the linear reciprocating energy from the outside applied to the piston rod 25 by converting it into electrical energy. Therefore, when the fluid pressure actuator 1 is used as a braking device or the like, the energy of the external force applied to the piston rod 25 can be regenerated as electrical energy.

Further, since the end portion 25c of the piston rod 25 protrudes from the second cover 23 of both rod cylinders 11, by attaching a position detection sensor such as a limit switch here, the axial position of the piston rod 25 And the rotation angle position of the rotation shaft 32 can be easily detected.

In particular, it is difficult to detect the rotation angle position of the rotation shaft 32 when the rotation angle exceeds 360 degrees, but the axial position of the piston rod 25 can be easily converted to the rotation angle position of the rotation shaft 32. Therefore, by detecting the axial position of the piston rod 25, the rotation angle position exceeding 360 degrees can be easily detected.

It is also easy to adjust and maintain such a position detection sensor.

Further, by providing a cushion mechanism at the stroke end of the piston 24 in both rod cylinders 11, it is possible to easily stop the piston 24 smoothly at the stroke end and the rotating end.

In the fluid pressure actuator 1 described above, since the piston rod 25 is hollow and the rotating shaft 32 is housed therein, the shape seen from the axial direction is substantially circular as a whole and is compactly configured. ..

In the above-described embodiment, since the ball screw is used as the female screw 31 and the rotating shaft 32, it is excellent in terms of exercise performance and options. However, as long as it operates smoothly, it may be other than a ball screw. Further, by replacing the ball screw with one having a different characteristic, for example, a relationship between the moving distance in the axial direction and the rotation angle, the fluid pressure actuator 1 having various different functions can be obtained.

In the fluid pressure actuator 1 described above, since both rod cylinders 11 and the linear / rotation conversion device 12 have a relatively independent configuration, mutual maintenance is easy. For example, when the female screw 31 is worn and replaced with a new one, the female screw 31 can be easily replaced by loosening the bolt 31b and removing the female screw 31 from the piston rod 25. Further, when it is desired to change the conversion characteristics of the straight line / rotation conversion device 12, the straight line / rotation conversion device 12 can be easily replaced. As described above, in these cases, it is not necessary to disassemble both rod cylinders 11, and maintenance and the like can be easily performed.

Next, the fluid pressure actuator 1B of another embodiment will be described.

FIG. 7 is a cross-sectional view of the fluid pressure actuator 1B according to another embodiment of the present invention.

In FIG. 7, elements having the same function as the fluid pressure actuator 1 shown in FIG. 5 are designated by the same reference numerals, and description thereof will be omitted.

In FIG. 7, the shaft support portion 33 is attached to a bracket 41 fixed to the outer end surface of the first cover 22.

The bracket 41 has a cylindrical portion 41a, a flange-shaped portion 41b provided at the base end portion of the cylindrical portion 41a, and a bottom portion 41c provided at the tip end portion of the cylindrical portion 41a.

The outer shape of the cylindrical portion 41a is smaller than the outer shape of the cylinder tube 21.

The collar-shaped portion 41b is fixed to the outer end surface of the first cover 22 by bolts 42, and the shaft support portion 33 is attached to the bottom portion 41c by bolts 33d. The columnar shaft portion 32b of the rotating shaft 32 penetrates a hole provided in the bottom portion 41c.

The cylindrical portion 41a, the cylindrical portion 4a, and the flange-shaped portion 4b may or may not be continuous surfaces. That is, for example, a plurality of window portions may be provided on the peripheral surface of the cylindrical portion 4a. The flange-shaped portion 4b may be only a portion to which the bolt 42 is attached.

Then, in order to attach the fluid pressure actuator 1 to another device, for example, a bracket is provided for attachment to the first cover 22, the second cover 23, or the cylinder tube 21, or the flange-shaped portion 4b of the bracket 41 is extended. It may be installed and also used as a mounting bracket.

By using such a bracket 41, the fluid pressure actuator 1 can be made more compact, and the appearance is also neat.

In the embodiment described above, the cylinder tube 21, the first cover 22, the second cover 23, the piston rod 25, the female screw 31, the rotating shaft 32, the shaft support portion 33, both rod cylinders 11, and the linear / rotational conversion. The configuration, structure, arrangement, number, material, combination, dimensions, and the like of the device 12 or the fluid pressure actuator 1 as a whole or each part can be various other than those described above.

1,1B Fluid pressure actuator 11 Double rod cylinder 12 Straight line / rotation converter 21 Cylinder tube 22 First cover 23 Second cover 24 Piston 25 Piston rod 25a Insertion holes 25b, 25c End 26 Pedestal 31 Female screw 32 Rotating shaft 33 Shaft support 34 Bracket 25Bc End 25Bd Screw Shaft (engagement)
41 Bracket 41a Cylindrical part 41b Collar-shaped part 41c Bottom 41c

Claims (10)

Cylinder tube and
A first cover fixed to the cylinder tube so as to close one end face of the cylinder tube,
A second cover fixed to the cylinder tube so as to block the other end face of the cylinder tube.
A piston that can slide axially along the inner peripheral surface of the cylinder tube,
An axial insertion hole is provided in the central portion, and the piston is integrally connected to the piston, and the first cover and the second cover are slid through the first cover in the axial direction and are rotated around the cylinder tube. With a piston rod that is restricted to non-rotatable in the direction,
A female screw attached to the end of the insertion hole of the piston rod,
A rotating shaft having a male screw screwed into the female screw and arranged so as to be able to enter the insertion hole.
A shaft support portion that is fixedly provided to the cylinder tube and supports the rotating shaft so as to be rotatable and axially immovable.
Have,
Along with the axial movement of the piston, the piston rod moves axially while penetrating the first cover and the second cover, and the rotation is caused by screwing the female screw and the male screw. The shaft is configured to rotate,
A fluid pressure actuator characterized by that. At the end of the piston rod opposite to the side to which the female screw is attached, an engaging portion for transmitting an axial driving force to the load is provided.
The fluid pressure actuator according to claim 1. The piston rod is regulated to be non-rotatable by being provided at a position eccentric from the center position of the cylinder tube.
The fluid pressure actuator according to claim 1 or 2. The piston rod is restricted from being non-rotatable due to its square outer cross section.
The fluid pressure actuator according to claim 1 or 2. The piston rod is restricted from being non-rotatable due to the oval external cross section of the piston.
The fluid pressure actuator according to claim 1 or 2. The shaft support is attached to a bracket fixed to a pedestal to which the cylinder tube is fixed.
The fluid pressure actuator according to any one of claims 1 to 5. The shaft support is attached to a bracket fixed to the outer end surface of the first cover or the second cover.
The fluid pressure actuator according to any one of claims 1 to 5. The bracket has a cylindrical portion, a collar-shaped portion provided at the base end portion of the cylindrical portion, and a bottom portion provided at the tip end portion of the cylindrical portion.
The brim-shaped portion is fixed to the outer end surface of the first cover or the second cover.
The shaft support portion is attached to the bottom portion,
The fluid pressure actuator according to claim 7. The outer shape of the cylindrical portion is smaller than the outer shape of the cylinder tube.
The fluid pressure actuator according to claim 8. Both rod cylinders are composed of the cylinder tube, the first cover, the second cover, the piston, and the piston rod.
The linear / rotation conversion device is composed of the female screw, the rotating shaft, and the shaft support portion.
The female screw is inserted into the insertion hole at the end of the insertion hole of the piston rod.
The fluid pressure actuator according to any one of claims 1 to 9.

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