JPH05280506A - Hydraulic actuator - Google Patents

Abstract

PURPOSE: To provide a hydraulic actuator having a simple structure and is easily assembled by utilizing a space for containing a piston rod in an actuating cylinder as a pressurized fluid reservoir, and by equipping the inlet/outlet control of the pressurized fluid through arranging a directional control valve between a pump and the actuating cylinder. CONSTITUTION: A structural unit 1 comprise an actuating cylinder 2 including an actuating piton 3, a pump 5 driven by a motor 6, a directional control valve 8, and a reservoir. A space 13, which receives an actuating piston rod 4 in the actuating cylinder 2, is utilized as a storage reservoir for the working fluid. In the output stroke of the actuating piston 3, a directional control valve 8 directly connects the space 13 with the intake port of the pump 5. At the end of the output stroke, the directional control valve 8 directly connects the intake port of the pump 5 with its delivery port, and also lowers the pump pressure by means of a switching means. Furthermore, an acting side A1 of the actuating piton 3 is connected to the space 13 to return the piston 3 to its initial position.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic actuating device, which hydraulic actuating device comprises an actuating cylinder, an actuating piston movable in the actuating cylinder, and an actuating piston adapted to be acted on by a pressure fluid. One side, an operating piston rod arranged on the other side of the operating piston, a return spring engaging the operating piston, a storage container for the pressurized fluid, a pump driven by a motor, and An intake side of the pump connectable to the reservoir and the pressure fluid, the pressure fluid being conveyed from the transfer side of the pump to the working piston, and conduit means for the pressure fluid,
And an adjustable switching valve for controlling the pressure fluid in the conduit means between the pump, the reservoir and the working piston.

[0002]

A hydraulically actuated hydraulically actuated device is known from DE 2218059.
In this patent application, an actuating cylinder with an actuating piston, a pump with a motor and a pressure fluid storage container form a structural unit, said structural unit being assembled together. However, this hydraulic actuation drive
It is a structural unit that costs a lot of money. In particular, the working piston with the piston rod is connected to a complex conduit system for controlling the working piston and is arranged in the housing, but results in a structure that requires a large space.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to make a conventional actuating device simpler, substantially space-saving and low-cost to manufacture, easy to assemble, and simple. The goal is to eliminate failures by structure.

[0004]

The above-mentioned object is: A A working cylinder having a working piston, a pump having a motor, a switching valve, and a storage container form an independent structural unit, and the independent structural unit comprises: A space adapted to be fitted to a united assembly, the space being located in the working cylinder opposite to one side of the working piston, in which the pressure fluid acts and the working piston The space containing the rod acts as a reservoir for the pressure fluid, and C for the performance of the power stroke of the working piston, the switching valve in the first position of the working cylinder acting as a storage container. Directly connecting the space to the intake side of the pump; D At the end of the output stroke, the switching valve in the second position is moved to the intake side of the pump. Reducing the pump pressure via a switch means and connecting the sides directly to each other, and the switching valve in the E third position with the side of the working piston being acted upon by the pressure fluid, Connecting the space of the working cylinder acting as a container,
A return spring is achieved according to the invention in combination with causing the working piston to be pushed back to its initial position.

The invention resides essentially in the idea of combining the working cylinder, the pump and the storage container into an independent structural unit for the working assembly, said working assembly of the working cylinder. There is a space, which contains the piston rod and at the same time acts as a reservoir for the pressurized fluid. The result is a small unit that can be manufactured without undue cost and that is space-saving and easy to assemble.
By removing electrical circuits and pressure fluid lines,
The device is less likely to fail.

[0006]

The preferred embodiments are described below in conjunction with the drawings which explain the invention in more detail.

As shown in FIG. 1, the hydraulic operating device includes an operating cylinder 2 having an operating piston 3 and an operating cylinder 2
It essentially comprises a pump 5 arranged therein and driven by an electric motor 6 via a conventional interlocking member 7 and a switching valve 8. Here, the working cylinder 2, the switching valve 8, the pump 5 and the motor 6 form a structural unit 1 which is fixedly connected to each other and assembled together.

The motor 6 is attached like a flange to a housing 9 including a switching valve 8 and an interlocking member 7,
The pump 5 is attached to the opposite side of the housing 9. The working cylinder 2 is connected to the housing 9 by means of a mounting rod 11, which acts as a tension rod.

The working piston 3 divides the cylinder cavity of the working cylinder 2 into two partial volumes. The partial volume 12, which has the piston side A1 as a reference surface, acts as a working space, inside which the pressurized fluid squeezes the piston side A1 of the working piston 3 and also pushes the piston to the extended position. The other partial volume 13 in which the working piston rod 4 is disposed is the piston side A2 as a reference surface.
And the piston side A2 is smaller than A1 due to the piston rod 4. The partial volume 13 is filled with the pressure fluid and acts as a storage container for the pressure fluid.

The pipe 14 opened to the switching valve 8
Connects the partial volume 12 with the partial volume 13 via the switching valve 8 and, in a special position, via the pump 5.

The partial volume 13 also includes two return springs 15,
16 and the return springs 15 and 16 are
Push to return from the extended position to the retracted position. During the pushing back, the pressurized fluid is conveyed from the partial volume 12 via the pipe 14, the switching valve 8 and in a special position the pump 5 to the partial volume 13.

As schematically shown in FIG. 2, the working cylinder 2
Are attached to a total of four attachment rods 11. Along the holes for the mounting rod 11 and the pipe 14, four further assembly holes 19 are provided in the end flange 18 of the working cylinder 2 so that in the working position it is the assembly of the complete structural unit 1. To

FIGS. 3 to 5 show different positions of the switching valve 8 for controlling the operation of the working cylinder 2. The switching valve 8 has a circular-cylindrical valve hole 20 and a circular-cylindrical valve hole 2.
0 has a valve piston 21 movable therein.
The valve piston 21 has two circle-cylindrical piston parts 21.
a, 21b, said two circular-cylindrical piston parts 21a, 21b being connected to each other via a valve piston rod 22 and having different axes but having the same radial dimension. A spring 23 is mounted on the valve piston rod 22 protruding from the housing 9, a part of which is supported by the housing 9. Valve piston rod 22
Extends to the switch-off means 24 at the end, which is also located outside the housing 9. Four pressure fluid flow paths 26,
27, 28, 29 open towards the valve hole 20 and are selectively connectable to each other depending on the position of the valve piston 21 in the valve hole 20. The pressure fluid flow path 26 communicates in a way not shown, more specifically via the hole 26a to the transfer side, ie to the outlet of the pump 5. Pressure fluid flow path 2
7 communicates with the intake side through the hole 27a, that is, with the inlet of the pump 5. The two branches 27c, 27d also open into the valve hole 20 in another position. The further branch 27b leads to the inlet area of the expandable reservoir 31 for pressurized fluid. The pressure fluid flow path 28 is connected via the hole 28a in a manner not shown, and more specifically, the partial volume 1 of the working cylinder 2.
Directly to 2. Two additional branches 28b and 28c
However, it is open to the valve hole 20 at another position. Similarly, valve hole 2
The pressure fluid flow path 29, which is open to 0, communicates with the partial volume 13 via the hole 29 a and the pipe 14.

The expandable reservoir 31 comprises a circular-cylindrical inlet area 32 and two circular-cylindrical reservoir holes 33, 34.
Extend from the circle-cylindrical inlet area 32 opposite one another. Reservoir pistons 35, 36 are respectively arranged for movement in the reservoir holes 33, 34. The reservoir pistons 35, 36 are pre-biased in the direction of the inlet section 32 by the reservoir springs 37, 38. Under the pressure generated by the pressure fluid in the inlet area 32 on the reservoir pistons 35, 36, the reservoir pistons 35, 36 move against the force of the reservoir springs 37, 38 and increase the inlet area 32. However, the inlet section 32 thus expands as the pressure increases and takes in to store the pressurized fluid.
The reservoir 31 can have an expanded inlet section 32 which can be activated in the expanded state, i.e. the inlet section 32 can be pre-filled with a pressure fluid. The inlet section 32 thus acts as a pressure fluid reservoir and can thus compensate for the slight loss of pressure fluid in the structural unit 1.

The valve piston 21 is moved in one or the other direction by the fluid pressure in the valve bore 20. The direction of movement is determined by the valve piston 2 entering the valve hole 20.
1 is the ratio of the force generated above to the force acting on the valve piston 21 outside the valve hole 20. The force acting on the valve piston 21 entering the valve hole 20 is applied by the spring 23, while the force acting on the valve piston 21 outside the valve hole 20 is mainly defined by the valve piston 21 inside the valve hole 20. And applied by fluid pressure in a closed volume on all sides. In this way, automatic control of the switching valve 8 by fluid pressure is achieved.

Also, the switching valve can be controlled, for example, electromagnetically or by an independent pressure relief valve corresponding to each pressure.

As shown in FIG. 3, the valve piston 21 has a pressure fluid flow path 2 extending from the transfer side, ie the outlet of the pump.
6 is in a position where it is connected to the branch 28b of the pressure fluid channel 28 which leads to the partial volume 12 via the valve hole 20. This causes pressure to act on the piston surface A1, so that the working piston 3 in the working cylinder 2 is moved to the extended position and does the work. At the same time, the intake side,
That is, the pressure fluid flow path 27 leading to the inlet of the pump is
Via the branch 27 d and the valve hole 20, it is connected to the pressure fluid flow path 29 leading to the partial volume 13. When the partial volume 13 forms a reservoir for pressurized fluid, the intake side of the pump is thus connected to the reservoir. This means that the pressure fluid is carried by the pump 5 from the partial volume 13 to the partial volume 12 when pressure is generated.

When the actuating piston 3 is almost completely extended and pushes the rivet via a tool, for example attached to the free end of the piston rod, so as to form a rivet head on the rivet, the switching valve 8 Is in the position shown in FIG. In this case, the pressure in the partial volume 12 rises further as the pump continues to pump the pressurized fluid drawn from the partial volume 13 into the partial volume 12.
However, the pressure also rises within the volume of the valve hole 20 which is defined by the position of the piston portion 21a within the valve hole 20 which is defined by the piston portion 21a.
Further, the pressure fluid flow path 26 and the branch 28 a of the pressure fluid flow path 28 are open. As a result, the valve piston 21 is
3 is pushed out of the valve hole 20 and thereby releases the connection of the pressure fluid channels 26, 28, said pressure fluid channels 26, 28 already having branches of the pressure fluid channel 27. 27
They are connected to each other by a valve hole 20 having c.
As a result, not only the pressure fluid moving through the branch 27b of the pressure fluid flow path 27 into the inlet area 32 of the expansion reservoir 31 but also by means of which the two reservoir pistons 35, 36 are
Against the force of the two reservoir springs 37, 38 respectively, respectively, pushed in opposite directions in the reservoir holes 33, 34 and the expanded volume of the expanded reservoir 31 is thus increased, but on the transfer side of the pump ( Even the pressure fluid flow passage 26) and the partial volume 12 (pressure fluid flow passage 28) are simultaneously connected to the intake side of the pump (pressure fluid flow passage 27) and the partial volume 13 of the working cylinder 2 acting as a storage container. To be done. In this position the end switch-off means 24 are simultaneously actuated by the valve piston rod 22 to switch-off or adjust the pump.

Finally, when the valve piston 21 is in the position shown in FIG.
And the branch 28a, 28b of the pressure fluid flow path 28 to the partial volume 12 of the working cylinder 2. At the same time, the volume between the valve piston parts 21a, 21b in the valve hole 20 is
Through the branch 28c of the pressure fluid channel 28, the partial volume 12
Connected to. This volume is in turn connected via a pressure fluid channel 29 and a branch 29a to a partial volume 13 of the working cylinder 2 which acts as a reservoir of pressure fluid. In this way, the two partial volumes 12, 13 of the actuating cylinder 2 are connected, and for this connection the two return springs 15, 16 in the partial volume 13 cause the piston to retract.

Furthermore, in the position of the valve piston 21 shown in FIG. 5, the two partial volumes 12, 13 are now connected and the intake side of the pump is not connected to the partial volume 13, but the working piston 3 is Depending on the pump that is switched on, the intake side of the pump may have a pressure fluid flow path 27 and a valve hole 2
It can be extended more quickly when it is connected to the partial volume 13 via 0 and the pressure fluid channel 29. In the position according to FIG. 5,
Therefore, before the position of the switching valve 8 shown in FIG. 3, a rapid movement of the working piston is possible, during which no force acts on the working piston 3. In the example of forming the rivet head described above, this rapid movement continues until a tool attached to the piston rod of the working piston hits the rivet.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a hydraulic actuator including a pump and a switching valve.

FIG. 2 is a cross-sectional view taken along the line II-II of FIG.

3 is a cross-sectional view of the switching valve of FIG. 1 in a first position for controlling the action of the working cylinder.

FIG. 4 is a view similar to FIG. 3, with the switching valve in the second position.

5 is a view similar to FIG. 3, with the switching valve in a third position.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Structural unit 2 ... Working cylinder 3 ... Working piston 4 ... Working piston rod 5 ... Pump 6 ... Motor 8 ... Switching valve 13 ... Space 14 ... Pipe 15, 16 ... Return spring 24 ... Switch means 26, 27, 28, 29 ... Pressure fluid flow path 31 ... Expandable reservoir A1 ... One side of working piston A2 ... Other side of working piston

Claims (4)

[Claims] 1. An actuating cylinder (2), an actuating piston (3) movable in the actuating cylinder (2), and one side (A1) of the actuating piston adapted to be acted on by a pressure fluid, An actuating piston rod disposed on the other side (A2) of the actuating piston, return springs (15, 16) engaging with the actuating piston (3), a reservoir for the pressurized fluid, a motor ( A pump (5) driven by 6), an intake side of the pump that is connectable to the storage container and the pressure fluid, the pressure fluid being carried from the transfer side of the pump to the working piston, and the pressure Conduit means (14, 26, 27, 28, 29) for the fluid,
A hydraulic actuating device comprising an adjustable switching valve (8) for controlling said pressure fluid in a conduit means between a pump, a reservoir and an actuating piston, said actuating device comprising: A actuating piston (3) A cylinder (2), the pump (5) having a motor (6),
The switching valve (8) and the storage container form an independent structural unit (1), and the independent structural unit (1)
Is adapted to fit into a united assembly, and B is a space (13) located in the working cylinder opposite to the side (A1) of the working piston (3), The pressure fluid acts in the space (13) and the space containing the working piston rod (4) acts as a reservoir for the pressure fluid, and C the output stroke of the working piston (3) is performed. for,
The switching valve (8) in the first position allows the space (1) of the working cylinder (2) to act as a storage container.
3) directly connecting the intake side of the pump (5); and D at the end of the output stroke, the switching valve (8) in the second position The intake side and the transfer side are directly connected to each other, and the switch means (2
4) reducing the pump pressure via E) said switching valve (8) in a third position, said side (A1) of said working piston (3) being acted upon by said pressure fluid; Connecting the space (13) of the working cylinder (2) acting as a container, the return spring (15, 16) pushing the working piston (3) back to its initial position. Hydraulic actuating device. 2. The switching valve (8) temporarily holds the third position when the pressure fluid starts to act on the working piston (3) before the output stroke and serves as a storage container. Hydraulic actuation according to claim 1, characterized in that the space (13) of the working cylinder (2) is connected to the side (A1) of the working piston (3) acted on by the pressure fluid. apparatus. 3. Hydraulic actuation according to claim 1 or 2, characterized in that the switching valve (8) is actuated by the pressure fluid whose pressure is kept constant by the pump (5). apparatus. 4. At the end of the output stroke, the switching valve (8) connects the transfer side of the pump (5) to an expandable store (31), which stores (31). The hydraulic actuating device according to any one of claims 1 to 3, wherein a part of the pressure fluid is taken in by.