JPH0128241B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a hydraulic actuator actuating device for operating a hydraulic actuator by controlling acceleration and deceleration within a predetermined stroke for a short period of time.

[Prior Art] As shown in FIG. 1, a conventional hydraulic actuator operating device of this type is one in which a hydraulic actuator 1 and a cylinder-type hydraulic pump 4 are directly connected through a pipe 8 so that the working medium oil flows back and forth. is possible.

[Problems and Objectives to be Solved by the Invention] In the hydraulic actuator actuating device shown in FIG. Since it is sealed between the chamber 6 and the chamber 6, and only moves back and forth between the two, it deteriorates in a relatively short period of time. That is, the lubrication performance deteriorates. When the hydraulic oil deteriorates, it causes abrasion of various mechanical parts, and especially when the seal parts wear out, oil leakage occurs, so that the hydraulic actuator cannot perform a predetermined stroke operation during forward movement.

By the way, if you replace the sealed hydraulic oil with new hydraulic oil, the above-mentioned problems caused by the deterioration of the hydraulic oil will be resolved, but since the hydraulic oil is sealed, when replacing it, the operating state of the hydraulic pump by the rotating cam must be checked. The hydraulic actuator must be forcibly stopped under such conditions, which has the disadvantage of impairing operating efficiency.

The present invention has been made to solve the above-mentioned drawbacks, and is designed to automatically replace the hydraulic oil while the device is in operation.

[Solving means and effects according to the present invention] A hydraulic actuator whose reciprocating chamber is connected to a pressure accumulator via piping, and a cylinder-type hydraulic pump which is directly connected to the reciprocating chamber of the hydraulic actuator so that working medium oil can be passed back and forth through a conduit. a rotary cam, the cam surface of which the actuating rod of the hydraulic pump contacts, at least an actuator forward stroke zone, an actuator stroke holding zone, and an actuator backward stroke zone formed in series in this order; A relief valve is connected to the pipe near the hydraulic actuator side of the pipe, and a check valve and a two-port solenoid valve that only allow the working medium oil to flow into the pipe are installed near the hydraulic pump side of the pipe. A high-pressure oil generator, which is connected to pipes in this order from the pipe line side, and is configured to allow hydraulic oil with a pressure higher than the set pressure of the relief valve to flow in through the electromagnetic valve and the check valve; The rotary switch is connected to the camshaft and commands to switch the two-port electromagnetic valve to the oil supply position in accordance with the stroke holding zone of the rotary cam. Then, when the actuator working medium oil confined between the hydraulic actuator and the cylinder-type hydraulic pump is maintained in the stroke of the rotary cam after the hydraulic actuator has moved forward, the solenoid valve is opened, and the high-pressure working oil is pumped from the high-pressure oil generator into the pipe. The oil was sent into the pipeline, thereby replacing the hydraulic fluid in the pipeline.
Further, a hydraulic actuator is provided, in which a pressure accumulator to which a hydraulic pump is connected via piping is connected to the double-acting chamber, and the piston area on the double-acting chamber side is large and the piston area on the double-acting chamber side is small; A cylindrical hydraulic pump that is directly connected to the forward movement chamber of the actuator through a conduit so that working medium oil flows back and forth, and a cam surface that contacts the actuating rod of the hydraulic pump are connected at least to the actuator forward stroke zone and the actuator. A rotary cam configured by forming an actuator stroke holding zone and an actuator double stroke zone in series in this order, and a relief valve connected to a portion of the pipeline near the hydraulic actuator side, A check valve and a two-port solenoid valve that only allow the working medium oil to flow into the pipe line are interposed in this order from the pipe line side between the vicinity of the hydraulic pump side and the reciprocating chamber of the hydraulic actuator. The camshaft is connected to a pipe, and hydraulic oil having a pressure higher than the set pressure of the relief valve is discharged from the pressure accumulator and flows into the pipe via the solenoid valve and the check valve. 2 corresponding to the stroke holding zone of the rotary cam.
Equipped with a rotary switch that commands the port type solenoid valve to switch to the refueling position.

Then, the solenoid valve is opened when the actuator working medium oil confined between the hydraulic actuator and the cylinder-type hydraulic pump maintains the stroke of the rotary cam after the hydraulic actuator has moved forward.
High-pressure hydraulic oil is sent into the pipe from the pressure accumulator 3', thereby replacing the hydraulic oil in the pipe.

[Example] Hereinafter, the example will be explained with reference to the drawings.
In Fig. 2, 1 in the figure is a hydraulic actuator,
A pressure accumulator 3 is connected to the reciprocating chamber 2 through piping. 4 is a cylinder type hydraulic pump, 5 is a rotary cam that operates the cylinder type hydraulic pump 4, and the actuator forward stroke zone A-B is formed on its curved surface.
, a stroke holding zone BC, an actuator double stroke zone CD, and a non-stroke zone DA are formed in this order.

The reciprocating chamber 6 of the hydraulic actuator 1 and the cylinder chamber 7 of the cylinder type hydraulic pump 4 are directly connected through a conduit 8 so that the working medium oil flows back and forth. A pipe line 10 having a relief valve 9 interposed therein is connected to a portion of the pipe line 8 near the hydraulic actuator side.
Further, a high-pressure oil generator 13 is connected to the hydraulic pump in the vicinity of the hydraulic pump by connecting a check valve 11 and a two-port electromagnetic valve 12 in this order from the pipe line 8 side. The high-pressure oil generator 13 includes a hydraulic pump 14 that always discharges hydraulic oil at a pressure higher than the set pressure of the relief valve 9, and a relief valve 15 whose set pressure is higher than that of the relief valve 9. The two-port solenoid valve 12 is interlocked with a rotary switch 16 that is directly connected to the camshaft of the rotary cam 5, and is turned ON only between stroke holding zones B and C of the rotary cam 5. ing. Reference numeral 17 denotes a low-pressure hydraulic oil replenishment device connected to the pipe line 8 and has the structure described below.

That is, a cylinder type pressure accumulator 20 that is divided into two parts, an air chamber 18 and a hydraulic oil chamber 19, and an air-operated hydraulic pump 21 that feeds hydraulic oil into the hydraulic oil chamber 19 of the pressure accumulator 20 are connected by a pipe 22. This pipe line 22 is connected to the pipe line 8 via a check valve 23. The air-operated hydraulic pump 21, the air chamber 18 of the pressure accumulator 20, and the air source 24 are connected to the air-operated hydraulic pump 21 with a pressure reducing valve 25 and a two-port solenoid valve 26 interposed in this order from the air source 24 side. The air chamber 18 of the pressure accumulator 20 is connected to a pressure reducing valve 25 and a two-port solenoid valve 26.
They are connected by a conduit 28 branched from the conduit between them. 29a and 29b are the cylinder type pressure accumulators 20;
This is a detector disposed on the side of the piston rod 30 of the piston rod.

Both detectors 29a, 29b and the two-port solenoid valve 26 are interlocked via a line 31.
When the detector 29b detects the lower end of the piston rod 30, the solenoid valve 26 is turned on and switched, and pressurized air flows into the hydraulic pump 21.
is activated and sends hydraulic oil to the pressure accumulator 20.
Further, when the detector 29a detects the lower end of the piston rod 30, the solenoid valve 26 is turned off, the pipeline is cut off, and the hydraulic pump 21 is stopped. The pressure inside the hydraulic oil chamber 19 of the pressure accumulator 20 is adjusted to a lower pressure than the pressure inside the pressure accumulator 3 connected to the hydraulic actuator 1, and the set pressure of the relief valve 9 is adjusted to the normal operating pressure of the hydraulic actuator 1. It is considered to be a higher pressure than hydraulic pressure. Fourth
The figure shows another embodiment. Components that are the same as those in the embodiment shown in FIG. 2 are designated by the same reference numerals, and their explanation will be omitted. In FIG. 4, in the hydraulic actuator 1A, the piston area of the backward movement chamber 2 is small and the piston area of the forward movement chamber 6 is large. 3' is double action chamber 2
This is a pressure accumulator connected to the pipes and has the structure shown below.

That is, a cylinder type pressure accumulator 20' is divided into an air chamber 18' and a hydraulic oil chamber 19', and an air-operated hydraulic pump 21' feeds hydraulic oil to the hydraulic oil chamber 19' of the pressure accumulator 20'. It is connected to the reciprocating chamber 2 of the hydraulic actuator 1 through piping.

The air-operated hydraulic pump 21' and the air chamber 18' of the pressure accumulator 20' and the air source 24 are connected to the air-operated hydraulic pump 21', the pressure reducing valve 25', the two-port solenoid valve 26', and the air source 24. They are connected by a pipe 27' interposed in this order from the side, and the pressure accumulator 2
The air chamber 18' at 0' is connected to the pressure reducing valve 25' and the two-port electromagnetic valve 26' by a pipe line 28' branched from the pipe line between the two-port electromagnetic valve 26'.

29a' and 29b' are the cylinder type pressure accumulator 20'
This is a detector disposed on the side of the piston connecting rod 30'. Both detectors 29a', 29b' and the
The port-type solenoid valve 26' is interlocked with the line 31', and when the detector 29b' detects the lower end of the piston connecting rod 30', the solenoid valve 26' is turned on and switched, and pressurized air is supplied to the hydraulic pump 21'. Then, the hydraulic pump 21' is activated to send hydraulic fluid to the pressure accumulator 20'. Further, when the detector 29a' detects the lower end of the piston connecting rod 30', the solenoid valve 26' is turned OFF, the pipe line is cut off, and the hydraulic pump 2
1' is stopped.

The pressure within the hydraulic oil chamber 19' of the pressure accumulator 20' is higher than the set pressure of the relief valve 9 connected to the forward movement chamber 6 of the hydraulic actuator 1.

Since the present invention is configured in this way, the operation of the hydraulic actuator and the replacement of the hydraulic fluid sealed between the hydraulic actuator and the cylinder type hydraulic pump are performed as follows.

That is, when the rotating cam 5 is rotated in the direction of the arrow by the operation of the drive device (not shown), the piston 4' of the hydraulic pump 4 is pushed by the rotating cam 5 that is in contact with it via the roller 32, and the piston 4' of the hydraulic pump 4 is pushed into the cylinder chamber 7. Discharge hydraulic oil from. This hydraulic oil flows into the reciprocating chamber 6 of the hydraulic actuator 1 through the conduit 8 and moves the piston 1' to a predetermined stroke, that is, until it comes into contact with the cylinder wall. At this time, the hydraulic fluid in the reciprocating chamber 2 of the hydraulic actuator 1 is sequentially pushed out and flows into the pressure accumulator 3, where the pressure is accumulated.

When the rotating cam 5 is further rotated beyond the actuator forward stroke zone A-B and positioned in the stroke holding zone B-C, a signal is emitted from the rotary switch 16 installed on the camshaft, and the two-port solenoid valve 12 is activated. Switch, hydraulic pump 14
The high-pressure hydraulic oil discharged from the pipe passes through the solenoid valve 12 → check valve 11 → pipe 8 → pipe 10, is relieved at the relief valve 9, and is returned to the tank, so that the hydraulic oil in the pipe 8 is replaced with new hydraulic fluid. When the rotary cam 5 is further rotated and enters the actuator double movement stroke zone C-D, the hydraulic oil accumulated during the forward movement is discharged from the pressure accumulator 3 and flows into the actuator double movement chamber 2, and the piston 1' of the actuator 1 is Push back. At this time, the hydraulic oil in the reciprocating chamber 6 of the actuator 1 is discharged from the chamber 6 by the pushing back movement of the piston 1' and is returned into the hydraulic pump 4 through the conduit 8. In addition, if the hydraulic actuator 1 does not move back to the predetermined position due to some trouble, the low-pressure hydraulic oil sent from the low-pressure hydraulic oil supply device 17 is supplied to the hydraulic pump 4 through the pipe 22 → pipe 8. At the same time, the pressure of this supplied hydraulic oil causes the piston 4' of the hydraulic pump 4 to
is pushed out, and the state of contact with the curved peripheral surface of the cam is maintained. The hydraulic oil replenished in the previous process is relieved by the relief valve 9 in the next actuator forward movement process, so that there is no excess or deficiency of the sealed hydraulic oil. Thereafter, the same operation is repeated. By repeating the above operation, the hydraulic fluid confined between the hydraulic actuator 1 and the hydraulic pump 4 is simultaneously circulated and replaced, albeit slightly (by the amount of hydraulic fluid in the pipe 8). Therefore, the hydraulic oil can be replaced automatically without stopping the device, and deterioration of the hydraulic oil can be effectively prevented. In the device shown in FIG. 4, the hydraulic pressure on the backward movement chamber side of the hydraulic actuator 1A is set higher than the oil pressure on the forward movement chamber side (the pressure is set by the relief valve 9).
Since the piston area on the forward movement chamber side is large and the piston area on the backward movement chamber side is small, the hydraulic actuator 1 receives oil discharged from the hydraulic pump 4 and can perform forward movement without any trouble. When the solenoid valve 12 is switched in the stroke holding zone 5, high pressure hydraulic oil from the pressure accumulator 3' is transferred to the solenoid valve 12.
→ Check valve 11 → Pipe line 8 → Pipe line 10 is returned to the tank, so the hydraulic oil in the pipe line 8 is replaced with the hydraulic oil from the pressure accumulator.

[Effects] As described above, according to the present invention, the hydraulic oil that is used and confined between the hydraulic actuator and the cylinder type hydraulic pump can be replaced with new hydraulic oil little by little, thereby eliminating the inconvenience caused by deterioration of the hydraulic oil. In addition, since the hydraulic oil is automatically replaced while the equipment is operating, the operating efficiency of the equipment can be greatly improved compared to when the equipment is stopped, and it is also possible to measure the degree of deterioration of the hydraulic oil. Monitoring work is also unnecessary.

Furthermore, compared to the case where the hydraulic oil in the pipeline is replaced using high-pressure discharge oil from a dedicated high-pressure oil generator shown in Figure 2, in the example shown in Figure 4, high-pressure hydraulic oil from the pressure accumulator 3' is used in a branched manner. Since the hydraulic oil in the conduit is replaced by changing the hydraulic oil in the pipe, the construction becomes simple and has many advantages such as being advantageous in terms of equipment costs and maintenance.

[Brief explanation of drawings]

Fig. 1 is a conceptual diagram of a hydraulic actuator actuating device, Fig. 2 is a diagram showing a hydraulic actuator actuating device according to the present invention, Fig. 3 is a stroke/angle diagram of a rotating cam, and Fig. 4 is a diagram of a hydraulic actuator actuating device. It is a figure which shows another Example. 1, 1A... Hydraulic actuator, 2... Reciprocating chamber, 4... Cylinder type hydraulic pump, 3'... Pressure accumulator, 5... Rotating cam, 6... Forward moving chamber, 8... Piping, 9 ... Relief valve, 11 ... Check valve, 1
2... 2-port solenoid valve, 13... High pressure oil generator, 16... Rotary switch.

Claims (1)

[Scope of Claims] 1. A hydraulic actuator whose reciprocating chamber is connected to a pressure accumulator via piping, and a cylinder-type hydraulic pump which is directly connected to the forward chamber of the hydraulic actuator through a conduit so that working medium oil flows back and forth. a rotary cam, the cam surface of which the actuating rod of the hydraulic pump contacts, at least an actuator forward stroke zone, an actuator stroke holding zone, and an actuator backward stroke zone formed in series in this order; A relief valve is connected to the pipe near the hydraulic actuator side of the pipe, and a check valve and a two-port solenoid valve that only allow the working medium oil to flow into the pipe are installed near the hydraulic pump side of the pipe. A high-pressure oil generator, which is connected to pipes in this order from the pipe line side, and is configured to allow hydraulic oil with a pressure higher than the set pressure of the relief valve to flow in through the electromagnetic valve and the check valve; A hydraulic actuator operating device comprising: a rotary switch connected to a camshaft and commanding a two-port solenoid valve to be switched to a refueling position in accordance with a stroke holding zone of the rotary cam. 2. A hydraulic actuator in which a pressure accumulator to which a hydraulic pump is connected via piping is connected to a reciprocating chamber, and the piston area on the forward-moving chamber side is large and the piston area on the reciprocating chamber side is small, and the hydraulic actuator A cylindrical hydraulic pump that is directly connected to the forward movement chamber of the pump through a conduit so that working medium oil can flow back and forth, and the cam surface that the actuating rod of the hydraulic pump comes into contact with is at least the actuator forward stroke zone and the actuator stroke zone. A rotary cam configured by forming a holding zone and an actuator double stroke zone in this order in series, and a relief valve connected to a portion of the pipeline near the hydraulic actuator side, further comprising a hydraulic pump in the pipeline. A check valve that only allows the working medium oil to flow into the pipe line and a two-port electromagnetic valve are interposed in this order from the pipe line side to connect the piping between the side vicinity and the reciprocating chamber of the hydraulic actuator. In addition, hydraulic oil with a pressure higher than the set pressure of the relief valve is discharged from the pressure accumulator and flows into the pipe line via the solenoid valve and check valve, and is applied to the camshaft. 2 corresponding to the stroke holding zone of the rotary cam which is connected and equipped with
A hydraulic actuator actuating device characterized by comprising a rotary switch that commands a port type solenoid valve to switch to a refueling position.