JPH057587B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technology of the Invention] The present invention provides a casing body in which an oil tank is provided, a pump mechanism disposed inside the casing body to pump oil stored in the oil tank, and a casing body. A cylinder chamber formed within the cylinder chamber and supplied with pressure oil from the pump mechanism, a piston that is slidably disposed in the cylinder chamber in the axial direction and has a piston rod joined to the back surface, and an oil that communicates between the pump mechanism and the cylinder chamber. A hydraulic actuating device that is equipped with a switching valve that is disposed in a passage and switches the supply route of pressure oil, and performs a predetermined work by reciprocating a piston, and is characterized in particular by the structure of the switching valve. Relating to an actuation device.

[Technical background of the invention and its problems]

A hydraulic actuator that performs a predetermined work by reciprocating a piston using pressure oil pumped from a pump mechanism disposed inside the casing body;
For example, in a bending correction machine for correcting the bending of reinforcing bars, etc., a switching valve is provided to switch the pressure oil supply path because it is necessary to perform predetermined work during the forward and backward movements of the piston.

However, in conventional hydraulic actuators, the oil supply passage is completely sealed off by the switching valve during this switching operation, and if the electric motor is being driven, the oil pressure of the pressure oil will rise rapidly. This placed an overload on the pump mechanism and electric motor, causing their failure.

Therefore, in conventional equipment, when operating the switching valve, the operator must stop the electric motor and
It was necessary to temporarily stop the work and then perform the switching operation.

[Purpose of the invention]

The present invention has been made in consideration of these points, and provides a hydraulic actuator that does not overload the pump mechanism or the electric motor even if the switching valve is switched during operation of the pump mechanism. The purpose is to provide.

[Summary of the invention]

In order to achieve the above object, the present invention includes a casing body provided with an oil tank therein, a pump mechanism disposed within the casing body for pumping oil stored in the oil tank, and a pump mechanism formed within the casing body. A cylinder chamber to which pressure oil is supplied from the pump mechanism, a piston that is slidably disposed in the cylinder chamber in the axial direction and has a piston rod connected to the back surface, and an oil passage that communicates the pump mechanism and the cylinder chamber. In a hydraulically actuated device equipped with a switching valve arranged to switch a pressure oil supply route, the oil passage is connected to a pump mechanism, each having an opening in a cylindrical cylinder into which the switching valve is rotatably inserted. It consists of a connected oil supply passage, a reverse oil passage with an opening on the front side of the cylinder chamber, a forward oil passage with an opening on the rear side of the cylinder chamber, and a return passage communicating with the oil tank. It has a substantially sector-shaped symmetrical shape with a pair of tapers, a through passage is provided in the direction of the symmetrical axis, and a concave groove communicating with the through passage is formed in the widening part, and each oil passage and taper By the space formed between one taper and the inner wall of the cylindrical cylinder,
When the oil supply passage and the backward oil passage communicate with each other, the forward oil passage and the return passage communicate with each other through the space formed between the other taper and the inner wall of the cylindrical cylinder, and the one taper and the cylindrical cylinder When the retreating oil passage and the return passage are communicated by the space formed between the inner wall of the cylinder, the oil supply passage and the forward passage are connected by the space formed between the other taper and the inner wall of the cylindrical cylinder. The concave grooves formed in the diverging part of the switching valve are arranged in a relationship such that they communicate with the oil passage, and are located at positions opposite to the openings of the oil supply passage, the backward oil passage, and the forward oil passage into the cylindrical cylinder, respectively. Among the three openings of the return passage arranged to branch out, each opening has a width in the circumferential direction that allows two adjacent openings to communicate with each other.

According to the present invention, during the switching operation of the switching valve,
Even when the electric motor is driven and pressure oil is supplied from the pump mechanism, this pressure oil escapes to the return passage through the through-hole passage and groove, causing a sudden increase in the load on the pump mechanism, which can lead to malfunctions. It never happens.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is an external view of a bending correction machine according to the present invention. In the figure, reference numeral 11 denotes an electric motor, and the electric motor 11 is connected and fixed to the rear end of the casing body 12. At the front part of the casing body 12, a rod-like member R such as a reinforcing bar is provided with an arm 13.
is rotatably attached to the outer peripheral surface of the casing body 12. A pair of receiving arms 13 are attached at intervals, and a correction hook 14 is disposed between the receiving arms 13 to correct the bending of the rod-shaped member R in cooperation with the receiving arms 13. This hook 14 has a concave shape so as to be able to apply a pushing or pulling correction force to the rod-shaped member R, and is attached to the tip of a piston rod 15, which will be described later. Reference numeral 16 is a handle provided with a switch S for the electric motor 11, and reference numeral 17 is an auxiliary handle attached to the front portion of the casing body 12.

FIG. 2 is a sectional view showing the internal structure of the bending correction machine 10 according to the present invention. An oil tank 18 in which oil is stored is provided inside the casing body 12, and a pump mechanism 1 that pumps the oil in the oil tank 18 is provided.
9 are arranged. The pump mechanism 19 includes a cam portion 21 formed at the tip of a motor shaft 20 and a piston 22 that is reciprocated by the cam portion 21, and generates high-pressure oil by reciprocating the piston 22. The casing body 12 is
It is divided by a vertical wall 23 into an oil tank 18 in which a pump mechanism 19 is arranged and a cylinder chamber 24, and the pump mechanism 19, oil tank 18, and cylinder chamber 24 are communicated with each other by an oil passage provided in the vertical wall 23. .

The oil passages include an oil supply passage 25 connected to the pump mechanism 19, a retreat oil passage 26 having an opening on the front side of the cylinder chamber 24, a forward oil passage 27 having an opening on the rear side of the cylinder chamber 24, and an oil tank 18. The oil flow path is configured to be switched by a switching valve 30 provided in the vertical wall 23.

The switching valve 30 has a substantially cylindrical shape and is rotatably inserted into a cylindrical cylinder 29 formed within the vertical wall 23 . In the cylindrical cylinder 29, the other ends of the oil supply passage 25, the backward oil passage 26, the forward oil passage 27, and the return passage 28 are all open.

3 and 4 are partially enlarged views showing the state in which the switching valve 30 is inserted. The switching valve 30 is formed in a left-right symmetrical shape, and has a through passage 31 provided in the direction of the symmetrical axis, and tapers 32a, 32b that widen toward the end with starting points separated by a distance of Δ from the end of the through passage 31. is formed. These tapers 32a, 32b and each oil passage mentioned above are connected to one taper 32a and the cylindrical cylinder 29.
When the oil supply passage 25 and the retreating oil passage 26 are communicated with each other by the space 33a formed between the space 33a and the inner wall, the forward oil passage 27 and the return passage 28 are connected to the other taper 32b and the inner wall of the cylindrical cylinder 29. (see FIG. 3), and the retreat oil passage 26 and the return passage 2 are communicated with each other by the space formed between the taper 32a and the other taper 32a (see FIG. 3).
The oil supply passage 25 and the forward oil passage 27 are arranged in such a relationship that when they are communicated with each other, the space formed between the oil supply passage 25 and the forward oil passage 27 is communicated with the other taper 32b (see FIG. 4). There is. Also, the oil supply passage 25
The opening diameter d opening into the cylindrical cylinder 29 is
The distance is made slightly larger than the distance Δ from the end of the through passage 31 to the ends of the tapers 32a and 32b. The return passage 28 has openings 2 at positions facing the openings of the oil supply passage 25, the backward oil passage 26, and the forward oil passage 27 to the cylindrical cylinder 29, respectively.
8a, 28b, and 28c. The switching valve 30 has an opening 28 at its widening end.
a and 28c or openings 28b and 28c
A groove 34 is formed to communicate with the groove 34.
further communicates with the through passage 31.

Note that the switching operation of the switching valve 30 can be performed by rotating a lever 48 (FIG. 1) connected to the end of the valve.

Inside the cylinder chamber 24, a piston 35 having a piston rod 15 joined to the back surface is disposed so as to be freely slidable in the axial direction.
The piston rod 15 is moved backward by the pressure oil supplied to the rear side 24b (the right side in FIG. 2) of the cylinder chamber 24, and the piston rod 15 is moved forward by the pressure oil supplied to the rear side 24b of the cylinder chamber 24 (the right side in FIG. 2). It is becoming more and more popular. The piston 35 is provided with a plurality of through holes 36a, 36b in the axial direction, and in each of the through holes 36a, 36b, valve bodies 37a, 37b having a shape capable of closing the through holes 36a, 36b are inserted from the rear. The spring 38 is placed in a state where it is urged against the openings of the through holes 36a and 36b. Multiple valve bodies 37a, 37
b has protrusions 39a and 39b protruding from the end surface of the piston 35 at their tips, and one protrusion 3
The protrusions 9a protrude into the cylinder chamber 24a on the front side, and the other protrusion 39b protrudes into the cylinder chamber 24b on the rear side, so that they are arranged in opposite directions. Reference numeral 40 is a screw that receives the spring 38, and is hollow so that oil can pass therethrough.

A pair of springs 41 are attached to the outer circumference of the piston 35, which is made smaller one step inward than the sliding part.
a and 41b are mounted so as to protrude from the piston end face into the front cylinder chamber 24a and the rear cylinder chamber 24b, respectively.

The front end of the cylinder chamber 24 is sealed by an end wall 42, through which the piston rod 15 projects forward.

A pressure buffer cavity 43 is provided on the outer periphery of the casing body 12, and this cavity 43 is covered with an elastic rubber membrane 44. Further, the cavity 43 and the oil tank 18 are communicated through a release passage 45.

A circumferential groove 46 is formed on the outer periphery of the front part of the casing body 12, and a ring member 47 to which the rear end of the rod-shaped receiving arm 13 is fixed is rotatably fitted into the circumferential groove 46. ing. The degree of fitting of the ring member 47 is preferably such that the receiving arm 13 can be rotated manually. In addition, the auxiliary handle 17
is also fixed to the ring member 47.

Although not shown, a release passage leading to the oil tank 18 is connected in the middle of the oil supply passage 25, and a safety valve that opens the valve when a pressure higher than a predetermined level is applied is disposed in the middle of the oil supply passage 25. This results in
Even when the rod-shaped member has a bending correction capacity or higher, overload can be prevented from being applied to the pump mechanism 19 or the electric motor 11.

Next, the operation of this embodiment having such a configuration will be explained.

First, it is decided whether the rod-shaped member R to be corrected should be corrected by pulling (correcting by moving the hook 14 backward) or by pressing (correcting by moving the hook 14 forward), and then the switching valve 30 is selected by operating lever 48. In FIG. 2, the switching valve 30
is in position to be corrected by tension. Next, as shown in FIGS. 1 and 2, the rod-shaped member R is
It is inserted between the tip projection 13a of the receiving arm 13 and the hook 14. In the case of tension correction, the rod-shaped member R is placed in contact with the front side of the protrusion 13a as shown in the figure, and in the case of pressure correction, it is placed in contact with the rear side of the protrusion 13a.

After setting the rod-shaped member R and the bending correction machine in this way, when the switch S of the electric motor 11 is pressed, the motor shaft 20 and the cam part 21 are rotationally driven, and the piston 22 moves back and forth to drain the oil in the oil tank 18. Suction and compression generates pressure oil. The pressure oil generated by the pump mechanism 19 is sent under pressure to the cylindrical cylinder 29 through the oil supply passage 25, and as shown in FIG.
The oil is supplied to the retreat oil passage 26 through the space 33a. The pressure oil supplied to the retreating oil passage 26 is introduced into the front cylinder chamber 24a, thereby pressing the piston 35 and moving it backward (rightward in FIG. 2). As the piston 35 retreats, the piston rod 15 and the hook 14 move backward, and the rod-shaped member R is pulled and bent between it and the receiving arm 13 for correction.

During this time, the oil in the rear cylinder chamber 24b is returned to the oil tank 18 through the forward oil passage 27, the space 33b, and the return passage 28.

When the piston 35 moves backward at the final position, the protrusion 39b of the valve body 37b attached to the piston 35
comes into contact with the end face of the vertical wall 23, and the valve body 37b retreats against the force of the spring 38. As a result, the through hole 36b is opened, and the pressure oil in the front cylinder chamber 24a flows to the rear cylinder chamber 24b. As a result, the movement of the piston 35 is stopped, and
Overloading the pump mechanism 19 and electric motor 11 is prevented. Also, at this time, the spring 41b is compressed between the piston 35 and the vertical wall 23, and the end surface of the piston 35 is slightly lifted from the vertical wall 23 due to the elastic force of the spring 41b, and the valve body 37b opens the through hole. 36b is closed in place to prevent pressure oil from escaping and preventing reverse movement. By releasing the pressure oil in the cylinder chamber at the final movement position of the piston 35 in this manner, the switching valve 30 is prevented from becoming heavy, and the switching operation can be performed easily.

Next, when correcting the bending of the rod-shaped member R by pressing, the rod-shaped member R is held on the hook 1 as described above.
4 and the receiving arm 13, and the switching valve 30 is rotated to the position shown in FIG. 4 by operating the lever 48. During this switching operation, the opening diameter d of the oil supply passage 25 is made slightly larger than the distance Δ from the end of the through passage 31 to the ends of the tapers 32a, 32b, so the switching valve 3
The oil supply passage 25 is not completely sealed by the distance Δ of 0. Therefore, even if the electric motor 11 is driven during the switching operation of the switching valve 30 and pressure oil is supplied from the pump mechanism 19, this pressure oil passes through the through hole 31 and the groove 34 and returns to the return passage 28. As a result, the load on the pump mechanism 19 will not suddenly increase and cause a failure.

After switching the switching valve 30 to the position shown in FIG. 4, pressure oil is transferred from the pump mechanism 19 to the oil supply passage 25.
When supplied, the pressure oil flows into the forward oil passage 27 through the space formed between the taper 32b and the inner wall of the cylindrical cylinder 29, and further flows into the rear cylinder chamber 24b. As a result, the piston 35 moves forward in the left direction in FIG. 2, and the piston rod 15 and the hook 14 perform a forward pressing movement. When the piston 35 moves to the final forward position,
As described above, the protrusion 39a of the valve body 37a comes into contact with the end wall 42, the valve body 37a retreats, and the pressure oil in the cylinder chamber 24b is released from the through hole 38 to the cylinder chamber 24a. Also, during forward movement,
The oil in the front cylinder chamber 24a is transferred to the rearward oil passage 2.
6. Through the space formed between the taper 32a of the switching valve 30 and the inner wall of the cylindrical cylinder 29,
The oil is returned to the return passage 28 and the oil tank 18.

Similarly, when switching the switching valve 30 from the position shown in FIG. 4 to the position shown in FIG. Failure of the electric motor 11 due to overload is prevented.

When working with the bending correction machine 10 according to this embodiment, the operator usually holds the handle 16 and the auxiliary handle 17, and holds the receiving arm 13 and the hook 1.
4 is applied to the rod-shaped member R to be corrected. In this case, if the receiving arm 13 and the hook 14 cannot be placed in a position where the work is easy due to the position of the worker and the position of the rod-shaped member, the auxiliary handle 17 or the receiving arm 13 may be manually rotated. , can be set in the optimal position.

〔Effect of the invention〕

As explained above, according to the present invention, the oil supply passage is not completely sealed by the switching valve during the switching operation, so even if the switching operation is performed while the pump mechanism is operating, the oil supply passage is not completely sealed off by the switching valve. The motor will not be overloaded.

[Brief explanation of the drawing]

FIG. 1 is an external view of a bend correction machine according to the present invention, FIG. 2 is a sectional view of the bend correction machine, and FIGS. 3 and 4 are partially enlarged views of a switching valve. 12...Casing body, 13...Receiving arm, 14...Hook, 15...Piston rod,
18...Oil tank, 19...Pump mechanism, 24...Cylinder chamber, 25...Oil supply passage, 26...Reverse oil passage, 27...Forward oil passage, 28...Return passage, 29...Cylinder Cylinder, 30...Switching valve, 31...Through passage, 35...Piston, 37
a, 37b...valve body, 39a, 39b...protrusion,
41a, 41b... Spring, 46... Circumferential groove.

Claims (1)

[Claims] 1. A casing body having an oil tank provided therein;
A pump mechanism disposed within the casing body to pump oil stored in the oil tank; A cylinder chamber formed within the casing body and supplied with pressure oil from the pump mechanism; A cylinder chamber that slides in the cylinder chamber in the axial direction. A hydraulic actuator comprising: a piston that is freely disposed and has a piston rod connected to the back; a switching valve that is disposed in an oil passage that communicates a pump mechanism and a cylinder chamber and switches a pressure oil supply route; The oil passage includes an oil supply passage connected to a pump mechanism, each having an opening in a cylindrical cylinder in which a switching valve is rotatably inserted, and a retreating oil passage having an opening on the front side of the cylinder chamber. a forward oil passage having an opening on the rear side of the cylinder chamber;
The switching valve includes a return passage communicating with the oil tank, and the switching valve has a substantially fan-shaped symmetrical shape with a pair of left and right tapers, a through passage is provided in the direction of the symmetrical axis, and the through passage is formed in the widening part. A concave groove is formed in communication with each of the oil passages and the taper, and a space formed between one of the tapers and the inner wall of the cylindrical cylinder allows the oil supply passage and the retreating oil passage to communicate with each other. when the forward oil passage and the return passage are in communication with each other through the space formed between the other taper and the inner wall of the cylindrical cylinder, and the space formed between one of the tapers and the inner wall of the cylindrical cylinder. Therefore, when the backward oil passage and the return passage are communicated with each other, the oil supply passage and the forward oil passage are arranged in communication with each other due to the space formed between the other taper and the inner wall of the cylindrical cylinder. The concave groove formed in the end-widening part of the switching valve is connected to a return passage that is branched and arranged at a position facing the opening of the oil supply passage, the backward oil passage, and the forward oil passage into the cylindrical cylinder, respectively. A hydraulically actuated device characterized in that each of the three openings has a width in the circumferential direction that allows two adjacent openings to communicate with each other. 2. Claim 1, characterized in that the diameter of the opening of the oil supply passage into the cylindrical cylinder is slightly larger than the distance from the end of the through passage to the respective ends of the pair of tapers. Hydraulic actuation device as described in section.