JPH084232Y2 - Hydraulic actuator - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to a hydraulic actuator used for plastic working such as diameter-expanding processing of a pipe end of a metal tube, drilling, and cutting work.

[Conventional technology]

As this type of hydraulic actuator, many small-sized hydraulic actuators are used that are manually held by workers or fixed on a workbench at the site of piping work, construction work, etc. Generally, a type driven by a dynamic hydraulic cylinder is used. This single-acting cylinder is connected to a hydraulic pump, and when the pressure oil from this pump is fed into the pressurizing chamber of the hydraulic cylinder, the piston rod projects and various machining operations are performed with tools, and the piston returns after machining. The movement is performed by a return spring.

[Problems to be solved by the device]

By the way, in order to make the piston return movement, it is necessary to stop the movement of the hydraulic pump and further open the pressure oil supply pipe line from the hydraulic pump to the single-acting cylinder to return the oil to the oil tank. Conventionally, for this purpose, a manually operated valve connected to the pressure oil supply line was used, this valve was opened to return the oil to the oil tank, and after the piston returned, this valve was closed to prepare for the next pressure oil supply. However, it was dangerous to operate the valve by releasing the hand during the machining work, and it was troublesome and the work efficiency was poor. Further, instead of using the above manual valve, JP-B-53-47269 proposes a hydraulic actuator in which a return valve provided in the piston opens and closes an oil passage hole formed in the piston. However, in the case of this hydraulic actuator, the return operation cannot be performed unless the piston reaches the stroke end, and after some processing such as improper processing position or the detection of obstacles, the piston is returned. Even if it is desired, there is a problem that the piston does not return, which is inconvenient, which is also unfavorable for safety.

This invention solves the above-mentioned conventional problems. It is possible to automatically drain oil from the pressurizing chamber of the single-acting cylinder by simply stopping the operation of the hydraulic pump, and The present invention aims to provide a hydraulic actuator that is labor-saving, safe, and has excellent work efficiency.

[Means for solving the problem]

The hydraulic actuator of the present invention, however, has a single-acting cylinder containing a piston for driving a tool, a return spring for returning the piston, and a pressurizing chamber of the single-acting cylinder, the discharge side of which is connected to an oil tank. In a hydraulic actuator having a hydraulic pump connected to the suction side and in which the low-pressure chamber of the single-acting cylinder communicates with the atmosphere, a pressure oil supply passage connected to the hydraulic pump is provided in a valve chamber having an opening at one end. A cylindrical main valve body having one end side opening is slidably fitted, and a projecting shaft that is freely fitted into and disengaged from an inner diameter part of the main valve body is provided at the one end part of the valve chamber so as to project therefrom. A valve seat is provided at the other end of the valve chamber, the valve seat communicating with the oil tank via an oil drain passage, and the engagement piece engages with the main valve body when the main valve body moves toward the protruding shaft side. A sub-valve body that has a portion that can be brought into and out of contact with the valve seat, is slidably attached to the main valve body. A main spring for urging the main valve body toward the protruding shaft side is mounted between the main valve body and the wall surface of the valve chamber, and the main valve body or between the protruding shaft and the sub valve body is mounted. A sub-spring for urging the sub-valve toward the valve seat side is mounted, and an oil supply / discharge passage that opens at a position near the valve seat of the valve chamber is connected to a pressurizing chamber of the single-acting cylinder, The main valve body is provided with an oil passage hole that connects the inner diameter portion of the main valve body and the oil supply / discharge oil passage.

[Action]

In the hydraulic actuator of this invention, when the hydraulic pump is operated, the pressure oil supplied from the pressure oil supply passage into the valve chamber moves the main valve body toward the valve seat side, and the sub valve body moves together with this main valve body. Sits on the valve seat to shut off between the valve chamber and the oil drain passage. Due to the movement of the main valve body, a clearance is formed between the open end of the inner diameter part of the main valve body and the protruding shaft, and the pressure oil from the pressure oil supply passage is supplied and discharged from this clearance through the oil passage hole of the main valve body. Flowing into the oil passage,
The piston is driven by being supplied into the pressurizing chamber of the single-acting cylinder, and the piston operates a tool to perform work-piece processing such as diameter expansion processing, drilling, and cutting. If the operation of the hydraulic pump is stopped after processing, the main valve element and the sub valve element are driven toward the salient shaft side by the main spring, and the auxiliary valve element is separated from the valve seat, and the oil supply / exhaust passage becomes the oil discharge passage. Since they communicate with each other, the oil in the pressurizing chamber of the single-acting cylinder returns to the oil tank through the oil discharge passage, and the piston returns to the returning position by the spring. Further, when it is desired to return the piston in the middle of work after the piston is driven by the pressure oil, if the hydraulic pump is stopped at an arbitrary point, it returns to the return position by the same operation as described above.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS.

1 and 2 show the overall configuration of the hydraulic actuator 1, 2 is a housing that houses a pump and valves,
Reference numeral 3 denotes a casing which is connected to the housing 2 and which houses a gear mechanism and an oil tank and holds a second oil tank 46 (described later). Reference numeral 4 denotes a pump driving electric motor which is connected to the casing 3 and includes a switch 5a provided on the handle 5. On / off control is performed by manual operation. Reference numeral 10 is a single-acting cylinder, which is a single-acting hydraulic cylinder connected to the housing 2. A piston 13 is fitted in a pressurizing chamber 12 provided in the cylinder body 11,
The piston rod 14 is integrally fixed to the piston 13, and the piston 13 is biased toward the return side where the piston rod 14 is retracted by a return spring 15 composed of a compression spring. The low pressure chamber 16 on the piston rod 14 side in the cylinder body 11 communicates with the atmosphere. Reference numeral 20 is a tool (expander) attached to the tip of the single-acting cylinder 10 for expanding the diameter of the pipe material. The wedge tool 21 is formed by processing the tip of the piston rod 14 into a tapered conical shape, and this wedge. A pressing piece 23 (see FIG. 2) formed by radially dividing a short cylindrical body with a collar provided with a wedge surface 22 with which the tool 21 is slidably engaged, and a cap for guiding each pressing piece 23 in the diameter direction. The holder 24 having the shape of a ring is used as a main component. 25 is a pin fixed to the brim of the pressing piece 23, 26 is a guide hole for guiding the piston 25, 27 is a ring-shaped tension spring mounted so as to surround the outer circumference of the brim of all the pressing pieces 23. Center the pressing piece 23 (center of the wedge tool 21)
It urges toward. The holder 24 is the cylinder body
It is screwed to the tip of 11.

3 to 6 show the internal structure of the hydraulic equipment, and a drive shaft 32 driven by a rotary shaft of the electric motor 4 via a gear 31 is rotatably supported in the casing 3. . A plunger 33 is slidably fitted in the housing 2, and a compression spring 36 urges the outer circumference of a needle bearing 35 fitted to the outer circumference of an eccentric cam 34 fixed to the drive shaft 32. The head of Plunger 33 is pressed. 37 is a plunger plug for compression spring 36 set, 38
Is a check valve provided at the oil suction port 39 and opened when oil is sucked in, and 40 is a check valve provided at the discharge port 41 and opened when oil is discharged. 43
Is a pressure oil supply passage through which the discharge oil of the hydraulic pump 42 of the plunger pump type configured as described above flows, and communicates with the valve chamber 51. 45 is the first oil tank provided in the casing 3,
The oil suction port 39 is open to the first oil tank 45. Further, the casing 3 is further provided with a second oil tank 46 of variable volume type. The second oil tank 46 accommodates a bottomed cylindrical rubber tank 48 in a metal outer cylinder 47 screwed into the casing 3, and the base of the rubber tank 48 is pressure-bonded to the inner surface of the base of the outer cylinder 47 by a seal ring 49. A rubber tank 48 which is fixed and communicates with the first oil tank 45 is filled with hydraulic oil. 50
Is a vent hole protruding from the outer cylinder 47.

Further, as shown in FIG. 4, the valve chamber 51 has a housing 2
It is made by closing the round hole drilled in
43 is open at one end (side of the plug 52) 51a of the valve chamber 51. Reference numeral 53 denotes a bottomed cylindrical main valve body, a flange portion 53a of which is fitted to the inner wall surface of the valve chamber 51 and is slidable in the longitudinal direction along the inner wall surface, and the other end portion of the valve chamber 51 is provided. A main spring 54 mounted between the wall surface of 51b and the wall surface urges the plug 52 toward the plug 52 (on the side of the one end 51a of the valve chamber 51). Reference numeral 55 denotes a projecting shaft projecting from the plug 52, which is adapted to be inserted into and removed from the open end of the inner diameter portion 53b of the main valve body 53. 56 is the valve chamber 51
A valve seat provided at the other end 51b of the
Needle valve type auxiliary valve body 58 communicating with the oil tank 45
However, it is slidably held at the tip of the main valve body 53 so as to be brought into contact with and separated from the valve seat 56. Reference numeral 58a denotes a brim-shaped engaging piece that engages with and disengages from the inner surface of the tip of the main valve body 53, and a small-diameter auxiliary spring 59 is mounted between the engaging piece 58a and the protruding shaft 55. It is mounted to urge the sub valve body 58 in the direction toward the valve seat 56. Reference numeral 60 denotes an oil supply / drain passage, one end of which opens at a position closer to the valve seat 56 on the side wall of the valve chamber 51, more specifically, at a position closer to the valve seat 56 than the moving range of the flange portion 53a of the main valve body 53, and the like. The end portion is connected to the pressurizing chamber 12 of the cylinder body 11 of the single-acting cylinder 10.
Reference numeral 61 denotes an oil passage hole formed in the wall portion of the main valve body 53, which connects the inner diameter portion 53b of the main valve body 53 to the outside. Further, 62 is a direct-acting type relief valve, the pressure oil inflow port 63 is provided in a branch pipe line 64 portion branched from the oil supply / discharge oil passage 60, and the oil discharge outlet 65 is provided in the first oil tank 45. Is in communication with.

In order to expand the pipe end portion of the copper pipe for piping using the hydraulic actuator 1 having the above-described configuration, as shown in FIG. 8 (a), the wedge tool 21 is in the retracted state and in the reduced diameter state. On the pressing piece
23 is inserted into the tube end of the copper tube 70 to a predetermined depth. Next, if the switch 5a is manually pressed, the electric motor 4 rotates and the eccentric cam
The reciprocating motion of the plunger 33 driven by the 33 causes the hydraulic pump 42 to pump the pressure oil from the pressure oil supply passage 43 into the valve chamber 51. With this pressure oil, the main valve body 53 pressed against the plug 52 moves to the valve seat 56 side, and as shown in FIG. 7, the sub-valve body 58, which is moved integrally with the main valve body 53, moves. It sits on the valve seat 56 and closes the oil drain passage 57. Main valve body 53 is further seat 56
When the clearance 66 is formed between the opening end of the inner diameter portion 53b and the protruding shaft 55 as shown in FIG. 7, the pressure oil is supplied from the clearance 66 into the main valve body 53 and the communication hole. After passing through 61, the oil is supplied from the oil supply / drain passage 60 into the pressurizing chamber 12 of the single-acting cylinder 10, and the piston 13 is driven in the piston rod projecting direction. The protrusion of the piston rod 14 causes the wedge tool 21 to
It is pushed between 23 and the pressing piece 23 is driven in the diameter expanding direction as shown in FIG. 8 (b), whereby the tube end of the copper tube 70 is expanded.

After expanding the diameter in this way, switch 5a
When the pressure is released, the electric motor 4 is stopped and the pressure oil supply from the hydraulic pump 42 is stopped, so that the main valve body 53 is returned to the projecting shaft 55 side by the main spring 54, and along with this, the engaging piece portion. Since the sub valve body 58 is also returned in the same direction via 58a, the valve seat 56 is opened. As a result, the oil supply / discharge passage 60 communicates with the oil discharge passage 57, so that the oil on the pressurizing chamber 12 side in the cylinder body 11 is supplied / exhausted.
The state in which oil can be drained from 60 to the first oil tank 45, the piston rod 14 is driven in the retracting direction by the return spring 15, the wedge tool 21 returns to the return position shown in FIG.
By reducing the diameter of the copper pipe 70, the expanded diameter product of the copper pipe 70 can be taken out.

As described above, it is possible to perform the projecting and retracting operations of the piston rod 14 only by operating the switch 5a, so the operation is extremely simple. Further, after the piston rod starts projecting, the retracting operation can be performed at an arbitrary position, which is convenient and safe.

The present invention is not limited to the above-described embodiment, for example, the sub-valve element 58 may have a shape other than a needle valve such as a ball valve, and the engaging piece portion 58a of the sub-valve element 58 may have a shape other than a pin shape, such as a brim shape. The shape may be. In addition, the sub-valve element 58 is replaced with the valve seat 56.
The sub spring 59 biased to the side may be mounted between the main valve body 53 and the sub valve body 58. Further, the shape of the salient shaft 55 may be other than the above. Further, as the single-acting cylinder 10, a ram type cylinder or the like in which the piston and the piston rod have the same diameter may be used.

Also, the hydraulic actuator for expanding the diameter of the pipe end has been described above.
Alternatively, it can be widely applied to hydraulic actuators for various purposes such as cutting and drilling, in which case punches, cutters and other tools may be directly attached to the piston rod,
It may be indirectly driven via a roller or the like attached to the piston rod. Furthermore, this invention uses a return spring to move the piston rod at the protruding position (return position)
It can also be applied to a hydraulic actuator in which machining is performed with a tool when driven in the retracting direction by hydraulic pressure.

[Effect of device]

As described above, according to the present invention, by the main valve body and the sub valve body provided in the valve chamber, the pressure oil supply passage becomes the supply / discharge passage by the operation of the hydraulic pump, and the supply / discharge at the stop of the hydraulic pump. Since the oil passages are automatically connected to the oil discharge passages, respectively, the piston rod can be projected and retracted simply by operating the hydraulic pump to operate the switch, making the operation easy, safe, and highly efficient. An actuator is provided.

[Brief description of drawings]

1 to 8 show an embodiment of the present invention, FIG. 1 is a partially cutaway front view of a hydraulic actuator, and FIG. 2 is A- of FIG.
A side view of the line A, FIG. 3 is a longitudinal sectional view of a main part of the hydraulic actuator, FIG.
The drawing is a cross-sectional view taken along the line BB in FIG. 3, and FIG. 5 is the CC taken in FIG.
6 is a sectional view taken along line D-D of FIG. 5, FIG. 7 is a sectional view of a valve chamber portion showing an operating state, FIG. 8 (a),
(B) is a longitudinal cross-sectional view of a tool portion showing a usage state. 1 ... hydraulic actuator, 4 ... motor, 10 ... single-acting cylinder, 11 ... cylinder body, 12 ... pressurizing chamber, 13 ... piston, 14 ... piston rod, 15 ... return spring, 16 ... … Low pressure chamber, 20 …… Tool, 21 …… Wedge tool, 23 …… Pressing piece, 24
…… Holder, 39 …… Oil inlet, 42 …… Hydraulic pump, 43 ……
Pressure oil supply passage, 45 …… first oil tank, 46 …… second oil tank, 51 ……
Valve chamber, 51a ... One end, 51b ... Other end, 52 ... Plug, 53 ... Main valve body, 53a ... Brim part, 53b ... Inner diameter part, 54
...... Main spring, 55 …… Projection shaft, 56 …… Valve seat, 58 …… Sub valve body,
59 …… Secondary spring, 60 …… Supply / exhaust oil passage, 61 …… Oil passage hole.

Claims (1)

[Scope of utility model registration request] 1. A single-acting cylinder containing a tool-driving piston, a return spring for returning the piston, a pressurizing chamber of the single-acting cylinder, and a suction side connected to an oil tank. In a hydraulic actuator in which the low-pressure chamber of the single-acting cylinder is in communication with the atmosphere, a pressure oil supply path connected to the hydraulic pump has a valve chamber having an opening at one end, and the one end side is A tubular main valve body having an opening is slidably fitted, and a projecting shaft that can be inserted into and removed from the inner diameter part of the main valve body is projectingly provided at the one end of the valve chamber. The end portion is provided with a valve seat that communicates with the oil tank through an oil drain passage, and the valve is provided with an engagement piece portion that engages with the main valve body when the main valve body moves toward the protruding shaft side. A sub-valve that can be brought into and out of contact with a seat is slidably attached to the main valve, and the main valve and the valve A main spring for urging the main valve element toward the protruding shaft side is mounted between the main valve body and the wall surface, and the auxiliary valve element is provided between the main valve element or the protruding shaft and the auxiliary valve element. A sub-spring for urging to the side, and a supply / discharge oil passage that opens at a position near the valve seat of the valve chamber is connected to the pressurizing chamber of the single-acting cylinder, and A hydraulic actuator, comprising: an oil passage hole that connects the inner diameter portion of the main valve body and the oil supply / discharge passage.