JPS5980513A - Multistage double-acting hydraulic cylinder unit - Google Patents

Abstract

PURPOSE:To reduce a shock at the time of switching an operation by substantially equalizing each effective area on a backward side of each movable cylinder, and interposing a pressure compensating flow control valve in a hydraulic circuit to make the operation speed of the cylinder substantially constant. CONSTITUTION:Each effective area on backward side is substantially equalized by considering the area of backward side oil chambers 12, 13 of respective movable cylinders 4, 5 and the area of a feed pipe 9. A multistage double- acting hydraulic cylinder is reciprocated by switching a direction changing valve 23 of a hydraulic circuit, and the speed of such movement is adjusted by a pressure compensating flow control valve 24a at the forward movement, and adjusted by a pressure compensating flow control valve 24b at the backward movement. Since the effective areas on the backward movement side of respective movable cylinders 4, 5 are substantially equalized, even if the respective movable cylinders 4, 5 are sequentially switched and operated, the driving speed of a load can be kept substantially constant. Therefore, a shock produced at the time of switching the operation of each movable cylinder can be reduced remarkably.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a multi-stage double-acting hydraulic cylinder device that operates at a constant speed.

Multi-stage double-acting hydraulic cylinders in which a plurality of movable cylinders reciprocate in a telescopic manner are frequently used when a long stroke is required and installation space is limited.

However, in this type of cylinder, the speed is not constant because multiple movable cylinders operate sequentially during each forward or backward motion, and therefore, an impact is generated on the cylinder and load when the movable cylinder is switched. Because of this, there were limits to its uses.

The present invention has been made in view of the above-mentioned points, and provides a multistage double-acting hydraulic cylinder device that operates at a substantially constant speed despite its relatively simple configuration.

To explain the present invention in detail below, FIG. 1 shows an embodiment of a multi-stage hydraulic cylinder used in the present invention, in which a movable cylinder 4 having pistons 2 and 3 on the base end side, respectively, is provided in a basic cylinder 1. .5 are sequentially fitted, and a flow passage 6 is provided in the screw 1-2 of the first movable cylinder 4 in its axial direction, so that the forward-side fluid chambers 7 and 8 of each movable cylinder 12 and 13 communicate with each other. On the other hand, a passage tube 9 extending in the axial direction is provided protruding from the center of the piston 2 of the first movable cylinder 4, a flow passage 10 is provided in the radial direction of the piston 2, and a tube of the second movable cylinder 5 is provided. 5a has a plurality of communication holes 11 that communicate with the inside and outside of the duplex 5a near the connection part with the piston 3 (=J).
a, llb, and lc are provided to each movable cylinder 3, 4.
The reciprocating side fluid chambers 12 and 13 of the i! There is ζ.

Here, the piston 2 of the first movable cylinder 4 includes:
An annular groove 14 is provided corresponding to the opening on the outer periphery of the flow passage 10 provided in the radial direction.
The piston 2 is provided with a throttle hole 15 at one or a plurality of locations LJ to communicate the fluid chamber 12 with the reciprocating side fluid chamber 12. On the other hand, the tube la of the basic cylinder 1 has a thick wall portion 1b and a groove (1
A J part 1c is formed, and a J part is formed in the inner thick part 1b.
′! , head side supply 471 boat 16 and I-1' side supply/discharge boats 1 to 17 are installation numbers]. This I-171 side supply/discharge hole 7 is opened at a position slightly closer to the head side than the end of the reciprocating side fluid chamber 12 on the 1-' side, and the first movable cylinder 4 is located on the rono]' side. When the piston 2 moves in the - direction of the figure, the piston 2 acts slightly before it comes into contact with the rotor 1"' side end, and the flow path to the second movable cylinder 5 is changed. It will be done.

In addition, a plurality of flow holes 11a, llb, and llc provided in the tube 5a of the second movable cylinder 5 are provided in the axial direction, and the diameter increases sequentially from the screw 1 side. .

Therefore, when the second movable cylinder 5 moves forward and the piston 3 reaches the r and z side ends, the flow hole 11a
, llb, and llc are fitted into the cover 4a and closed in order from the one with the largest diameter, and the l'JI of the rhythm side fluid chamber 13 is
The outlet flow path is narrowed to provide a cushioning effect.

Now, on the piston 2 of the first movable cylinder 4, a cushion post Ill is formed at the center of the side facing the moving side fluid chamber 7, and the cushion post Ill is fitted to the throat cover 1d with a small gap between it and the cushion boss 1B. A matching cushion hole 19 is provided.

The cushion boss 1B has a recess 188 in the center of the end surface of the cylindrical object.
The cushion boss 8 has a shape in which the connecting part with the piston 2 is 1 yen smaller, and the axial length of the cushion boss 8 is longer than the depth of the cushion hole 10. It has a through hole 18b that extends through the fluid chamber 18b, and a small diameter throttle hole 1.8c that is connected to the through hole 18b and the forward fluid chamber 7. Therefore, when the ζ piston 2 moves back and the ζ cushion boss 18 is fitted into the cushion hole 19, the fluid in the cushion hole 19 has its discharge flow path constricted by the throttle hole 18c to obtain a cushioning effect, and the tip of the cushion boss 8 is The two bottom numbers of the cushion holes 19 abut against each other and act as a stopper.

A cushion device similar to the above-mentioned cushion device formed between the screws 1-2 of the first movable cylinder 4 and the hen F' cover 1d of the basic cylinder 1 is used to connect the screws 1-3 of the second movable cylinder 5 and the It is formed between the screw 1 and the screw 2 of the movable cylinder 4. However, since the screw 1-2 has a circular passage tube 9 protruding from it, and this passage tube 9 passes through the piston 3, the screw 1-3 has a circular cushion boss 20, and The piston 2 has a cushion hole 21 that fits therein, and the cushion boss 20 has a small diameter throttle hole 2Qa.
are set up for each J.

By the way, by considering the area of the pulsating side oil chamber of each movable cylinder 4, 5 and the area of the communication pipe 90, the effective area of each reciprocating side can be made the same.

However, in reality, it is difficult to make them exactly the same due to factors such as material dimensions and processing errors, and there is no need to do so. ).

Next, to explain the hydraulic circuit, in FIG. Each discharge boat 17 has a directional switching valve 23.
There are two pressure-compensated flow control valves 2 between the rond side supply and discharge boat 17 and the directional control valve 23.
4a and 24b connected in series in opposite directions are interposed. These pressure compensated flow control valves 24a, 24b
This maintains a nearly constant flow rate even if the circuit pressure changes, and the flow rate can be adjusted externally. It also has a built-in check valve, allowing free flow in one direction. Therefore, by connecting these two in series in opposite directions, the flow rates in the forward and reverse combined flow directions can be adjusted separately.

Further, a hydraulic pump 26 and an oil tank 28 are connected to the directional switching valve 23 via a pressure reducing valve 25 and a check valve 27, respectively. The pressure reducing valve 25 is a head side supply/discharge valve) 1
6, and the check valve 2
Reference numeral 7 is for generating a constant back pressure by utilizing crack knocking pressure in the free flow direction. Reference numeral 29 is a relief valve. Therefore, each time the directional control valve 23 is switched, a hydraulic pressure source or an oil tank is selectively connected to 16.17, and the flow rate is controlled by pressure compensated flow control valves 24a and 24b. A controlled, regulated flow rate approximately constant at 1π flows.

The directional switching valve 23 used here has 4 points and 3 positions, but it is not limited to this as long as it does not fulfill the above-mentioned functions.For example, it may have 5 points and 3 positions, or 4 points. One to two positions or two three ball l-2 positions may be used. The check valve 27 also ensures that a constant low back pressure is generated, which ensures the sequence of operation of each movable cylinder 4.5 of the multi-stage double-acting cylinder 22. That is, when the piston 2 of the first movable cylinder 4 and the screw 1-3 of the second movable cylinder 5 are not in contact with each other, the pressure in the reciprocating side oil chamber 12, 13 of the first movable cylinder 4 is Since they work in opposite directions to balance each other, if there is pressure in the forward oil chamber 7, this will cause forward movement. Therefore, pressure is applied to the forward oil chamber 7 by the hydraulic pump 26 during forward movement and by the cracking pressure of the non-return check 27 during backward movement, so the first movable cylinder 4 moves earlier than the second movable cylinder 5. Move and then return later.

The amount of back pressure that should be applied to the forward oil chamber 7 during the backward movement of each movable cylinder 4, 5 is determined by the variation in the effective area of the backward movement side of each movable cylinder 4゜5, and the resistance 71 of each sliding part. The cranking pressure of the check valve must be determined by considering various factors such as differences, pressure drop due to the internal flow path, and the size of the effective area on the forward side. This ensures the order of operation of each movable cylinder, but due to the above-mentioned factors, ζ does not use the check valve 27,
A similar effect may also be achieved by using only the back pressure caused by the directional control valve 23 and piping resistance.

In the multi-stage double-acting hydraulic cylinder device configured as described above, the multi-stage double-acting hydraulic cylinder 22 moves back and forth by switching the directional control valve 23, and its speed is controlled by pressure-compensated flow rate control during forward movement. ζ by the valve 24a, and by the pressure-compensated flow control valve 24b during the backward movement, and since the effective areas on the backward movement side of each movable cylinder 4.5 are approximately the same, each movable cylinder 4.5 The drive speed of the load is kept almost constant even if the motors are sequentially switched and operated.

Therefore, it is possible to significantly reduce stray shock when the operation of each movable cylinder is switched.

As described above, the present invention sequentially fits a plurality of movable cylinders each having a piston on the base end side into a basic cylinder, and mutually connects the forward and backward oil chambers of each movable cylinder. A multi-stage double-acting hydraulic cylinder U°ζ is connected directly or indirectly to the forward-moving oil chamber and the backward-acting hydraulic cylinder, and the effective area of the backward-moving side of each movable cylinder is approximately the same. The movable side oil chambers are each connected to a directional control valve that selectively connects to a hydraulic power source or an oil tank, and a pressure-compensated flow control valve is interposed between the double-movement side oil chamber and the directional control valve. As a result, the operating speed of the multi-stage double-acting hydraulic cylinder can be made almost constant, and the shock caused by f [at the time of switching the operation of each movable cylinder] can be significantly reduced.

In addition, if the pressure compensation A1 flow control valve is connected to the original cars in the forward and reverse directions so that they can be adjusted separately, the forward and backward movement speeds can be adjusted separately, and the reciprocating movement speed can also be adjusted separately. It can be done. In addition, by intervening and connecting a check valve between the directional control valve and the oil tank so that a free flow occurs in the direction of the oil tank, the operating order of each movable cylinder can be adjusted by rl.
ll(M) and operation becomes stable.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is a sectional view of a multi-stage double-acting pressure cylinder, and FIG. 2 is a hydraulic circuit diagram. l...Basic cylinder, 2.3...Piston, 4,5
... Movable cylinder, 7.8... Forward side oil chamber, 12.
13... Double-acting side oil chamber, 22... Multi-stage double-acting hydraulic cylinder, 23... Directional switching valve, 24a, 24b... Flow rate control valve with pressure compensation, 26... Hydraulic pump (oil Ha)
, 27... Check valve, 28... Oil tank. Applicant Taiyo Tekko Co., Ltd. No. 21A Procedures Amendment Written Type) March 24, 1981 1, Case Description 1989 Patent Application No. 189888 2, Title of Invention Multistage Double-Action Hydraulic Cylinder Device 3, Relationship with the case of the person making the amendments Applicant Location (Residence) Name Taiyo Tekko Co., Ltd. 4, Agent Address: 1-1 Nagasu Nishi-dori, Amagasaki d1, Ujigo Prefecture, 680 February 2, 1980 (Delivery date: 1982) February 22) 6. Subject of amendment

Claims (3)

[Claims] (1) A plurality of movable cylinders each having a piston on the base end side are sequentially fitted into the basic cylinder, and the forward oil chamber and backward oil chamber of each movable cylinder are connected directly or directly to each other. Multi-stage double-acting hydraulic cylinders are connected indirectly, and the effective area on the double-acting side of each movable cylinder is approximately the same.
On the other hand, the forward oil chamber and the backward oil chamber are each connected to a directional control valve that selectively connects to a hydraulic power source or an oil tank, and a connection is made between the backward oil chamber and the directional control valve. A multi-stage double-acting hydraulic cylinder device in which a pressure-compensated flow control valve is interposed and connected to a pressure-compensated flow control valve. (2) The multi-stage double-acting hydraulic cylinder device according to claim 11, wherein the pressure-compensated flow rate control valve is connected so that the flow rate in each of the forward and reverse flow directions can be adjusted separately. (3) A check valve is interposed and connected between the directional switching valve and the oil tank so as to allow free flow in the direction of the oil tank. ) The multi-stage double-acting hydraulic cylinder device described in item 2.