KR100260545B1 - Magnetically operated drain valve of an electrohydraulic lifting module - Google Patents

Abstract

Disclosed is a self acting drain valve of an electrohydraulic lifting module. The valve is adjustable by means of a magnet against the spring, a shut-off element arranged in the shut-off direction on the main valve seat, a pilot valve driven by the magnet and arranged in the control room of the shut-off element, a throttle upstream of the control room, and a spring against the spring. And a blocking member of a pilot valve actuated by a magnet against a spring acting in the blocking adjustment direction or the opening adjustment direction, wherein a spring having a sharp characteristic curve is used, and the blocking element and the main valve seat Form a lift-dependent flow control device.

Description

Self-acting drain valve on electrohydraulic lifting module

The present invention relates in particular to a magnetically operated drain valve of an electrohydraulic lifting module for use in a stacker truck.

The concept of lifting modules is practically known in small, low cost stacker trucks, whereby drainage control of pressurized fluid is carried out by a black / white drain valve. And this can be seen from the D 7490/1 data sheet of the company Heilmeier & Weinlein, Munich 81673, printed in March 1996. In the drain valve, two different connection modes are possible. In the first mode, the drain valve shuts off the fluid without current flowing through the magnet. The lifting operation is controlled by the pump. And the lowering operation is controlled by the drain valve which is changed to the passing position by the applied magnet. For this lowering function, a pilot valve is fully open, so that the load pressure is in the open direction during the entire opening stroke via the differential surface of the blocking element in the relaxed state of the control room. Lift it up. In the second mode, the drain valve is maintained in the pass position without current flowing through the magnet. An auxiliary two-position switching valve is provided between the user and the branch on the drain valve side. Lifting and lowering operations are controlled by two valves. The drain valve is actuated to be in the shut off position by applying current to the magnet during the lifting operation, the two-position switching valve is under load, and the lifting speed is controlled by the pump. Before the drain valve is switched to the passing position, the drain valve is set to the shut off position and the two-position switching valve is set to the drain position for the lowering operation. Regardless of the above connection mode, no ramp function can be controlled in the lowering operation of the black / white drain valve, which is required for the stacker truck. The spring, which serves as the blocking spring in the first mode, and as the opening spring for the pilot valve in the second mode, is a soft spring in both cases. That is, the spring has an elastic property that lacks a significant upward slope. Furthermore, the area of the nozzle and passage of the pilot valve is as large as possible to obtain a quick response of the drain valve, for example, it is designed in consideration of the minimum drain flow rate. In order to ensure complete closure in the shut off state of the drain valve, the shutoff element cooperates with the main valve seat only as a seat function. In order to ensure that the load pressure is reliably maintained for a long time, such sealing is required.

`In more complex lifting modules used in large, expensive stacker trucks, the connection principle according to DE-C2-42 39 321 is known, where the drainage control is the so-called" truck-tight "mode of operation (extreme extremely Microleakage occurs and is carried out via a two-way flow controller called, for example, only 1 cm / hour of load movement is allowed). Although there is a ramp function during the unloading operation, instead the structural effort required for this is quite large, such lifting modules are not used for small, low cost stacker trucks for cost reasons.

It is an object of the present invention to provide a drain valve of the above-mentioned kind having a lamp function by itself so as to control the operation of lowering structurally simple and inexpensively. And despite this ramp function, efforts are made here to substantially maintain the well-established and simple structural principles of conventional black / white drain valves. Furthermore, the lower cut is not only permitted, but also by a drain valve which can be used, for example, on larger and more complex stacker trucks which have been equipped with a complex lifting module according to DE-C2-42 39 321 so far. cut) Ramp function should be obtained.

1 is a block diagram of a first embodiment of a lifting module according to the invention.

2 is a block diagram of a second embodiment of a lifting module according to the invention.

3 is an enlarged cross-sectional view of the main portion of the drain valve according to the first embodiment of FIG.

4 is an enlarged cross-sectional view of a main portion of the drain valve according to the second exemplary embodiment of FIG. 2 in the longitudinal direction.

5 and 6 are detailed cross-sectional views of two variants.

7 is a diagram showing spring characteristics.

<Explanation of symbols for the main parts of the drawings>

6 ... Magnet 13 ... Insert

14 ... seat edge 15 ... slip hole

20 ... armature 24 ... plunger

25 ... head member 26 ... blocking member

27 Control room 29 Passage

31 Conical face 32 ... sliding protrusion

35 ... gap 38 ... limit

C ... pilot valve E ... flow regulator

G ... blocking element P ... pump

S ... Main valve seat T ... Tank

U ... overlap

According to the invention, the above object can be achieved by the features of claim 1. By replacing the previously used soft springs with rigid springs and the flow regulator as its component, a surprisingly sufficient clear cut ramp function can be obtained to control the lowering action. For example, by making only a few modifications to make most of the components of a conventional black / white drain valve available, the above concept of black / white drain valve can be maintained. In response to the applied current, the magnet can adjust the open position of the pilot valve which can be precisely pre-determined and accurately reproducible, the blocking element being adapted to the pilot valve by automatically adjusting the flow movement. The black / white function is replaced by the control function of the drain valve, and the flow regulating device regulates the amount of pressurized fluid to be drained, which is important for the lamp function. Ramp function occurs while the drain valve is open and shut off. Due to the small manufacturing effort, the drain valve is particularly suitable for small, low cost stacker trucks which are subject to considerable pressure on price. It is possible to implement the necessary "truck tightness" or, moreover, full tightness to maintain the load pressure. The magnet, which has been used in the black / white drain valve concept until now, can be easily modified by adapting its load characteristics to those of the light spring.

According to claim 2, the passage and the throttle size of the pilot valve of the upstream throttle are each additionally reduced. It is true that a more gentle response characteristic is obtained. However, such a property is advantageous for the required lamp function. The throttle and the passage may have the same size and should not actually be larger than 0.6 mm. However, the throttle is smaller than the passage for convenience. In practice, for example, a throttle with a diameter of 0.4 mm is arranged upstream of a passage having a size of approximately 0.5 mm. As a result, sudden start and sudden braking during the lowering operation can be largely avoided.

According to claim 3, the light spring acts on the blocking member in the blocking direction of the pilot valve, which can be adjusted in the opening direction by the movable armature of the magnet.

According to claim 4, the blocking member is alternatively biased in the opening direction of the pilot valve by the light spring. In both cases of claims 3 and 5, the position of the plunger that can be accurately predetermined and reproducible can be adjusted by the magnet, and the blocking element is adapted to the respective position of the plunger by flow movement.

The embodiment according to claim 5 is structurally simple and functionally reliable. When the conical face is pressed against the seat edge, it is in a completely closed blocking state. During the first rise of the cone-shaped surface from the seat edge, the pressurized fluid is introduced between the pilot valve and the sliding bore and the sliding portion before the opening raising action of the blocking element is increased and a kind of throttling control action takes place. It flows through the gap. Substantially uncontrolled flow of pressurized fluid occurs either just before or in a fully open state. Flow control through the stroke of the blocking element can be structurally precisely predetermined in its nature.

According to claim 6, the gap is within the range of standard sliding fits.

Advantageous embodiments in terms of manufacture are according to claim 7.

The embodiment according to claim 8 is simpler in terms of manufacturing, which results in some desired overlap so that no pronounced sudden start or sudden braking occurs.

According to claim 9, the overlap should be as narrow as possible.

According to claim 10, the lamp function can be achieved by using as many components of the black / white drain valve as possible, which has an advantageous effect on the manufacturing cost of the drain valve having the lamp function. In order to achieve the ramp function, it is only necessary to replace the spring and blocking member of the black / white drain valve and to slightly modify the magnet.

A rigid rigid spring having a sharp characteristic curve used in accordance with the invention is a spring having, for example, a characteristic with a working load of 13 N per spring displacement of 1 mm, whereas a soft spring with a flat characteristic curve is for example a spring of 1 mm. It has a characteristic that the working load per displacement is 8N.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

As shown in FIG. 1, in the lifting module H used in the stacker truck, the lifting operation is controlled by the cylinder Z, the speed and the degree of which are due to the pump P. FIG. And the module (H) has an operating line (1) extending from the pump (P) to the cylinder (Z), the pump (P) is driven by a motor (M). The pump (P) draws fluid from the tank (T) where the drain line (5) having two parts (5a, 5b) terminates therein, and the drain line (5) from the actuation line (1). Branching out Another drain line 3 comprises a system-pressure limiting valve 4. A check valve 2 for blocking the fluid towards the pump P is arranged on the actuation line 1 between the drain lines 3, 5. The self-acting drain valve V is provided between the portions 5a, 5b of the drain line 5, ie the control or regulating drain valve V as shown by the parallel lines. In the symbol notation according to FIG. 1, the blocking element of the drain valve V is shown as reference number 7, which can be adjusted to the blocking position shown by the spring 8, and the magnet 6. Can be adjusted to the passing position. According to the arrow 9, the magnet 6 can be excited by a variable current whose lamp function is controlled.

In FIG. 1, the drain valve V is cut off in a state where no current flows through the magnet 6. Since it has a ramp function, it is possible to sensitively control the gradual increase of the speed from the standstill of the load and the gradual increase of the speed up to the standstill during unloading operation, i.e. virtually no sudden start or sudden braking occurs. .

In contrast to the embodiment according to FIG. 1, according to FIG. 2 a two-position switching valve V2 is provided between the connecting portion 10 of the drain valve 5 and the cylinder Z. The switching magnet 11 can be switched from the blocking position to the passing position (black / white valve V2). The self-actuating shut-off valve V 'is also a control valve, and as shown in FIG. 2, the passage position is automatically maintained without current flowing in the magnet 6. When the magnet 6 is operated by the variable current (arrow 9), the magnet 6 is changed into various states, or the flow rate of the pressurized fluid to be discharged in an infinitely variable manner is controlled to a blocked state.

The configuration of the drain valve V for the connection mode according to FIG. 1 is based on FIG. 3. Inside the housing 11, a stepped hole 12 is provided across the portions 5a, 5b of the drainage line 5. The load pressure side is denoted by A, while B denotes the drain side toward the tank T. A sleeved insert 13 comprising a main valve seat S with a sharp (or optionally cornered) seat edge 14 is provided in the stepped opening 12 between the portions 5a, 5b. Located. After the sheet edge, a cylindrical sliding hole 15 is formed toward the drain side B. As shown in FIG. A plurality of open passages 17 communicate with the load pressure side A. FIG. The insert 13 is fixed to the stepped hole 12 by a screw body 18 supporting the magnet 6. As seen from the top of FIG. 3, the magnet 6 includes a coil 19 that can be operated by a variable current so that the movable armature 20 is adjusted. The armature 20 has a hole 21 in which the light spring 22 is filled, which spring 22 is held in a stop core of the magnet 6 (spring contact 23) and the hole 21 Bias the plunger 24 downward.

The plunger 24 has a head member 25, on which the spring 22 is positioned, and as shown in FIG. 3, the head member 25 is closed in the closed state of the drain valve V. As shown in FIG. It is located above the step 39 of the movable armature 20. The lower end of the plunger 24 has a substantially conical shape and forms the blocking member 26 of the pilot valve C. The pilot valve C monitors the connection between the control chamber 27 and the drain side B located on the upper side of the blocking element G, and is provided inside the blocking element G and designed as a cylindrical throttle hole. A passage 29 is provided. For the blocking element G, a weak blocking spring 40 is optionally included in the control room 27. The passage 29 is followed by a larger axial hole 30. A throttle 28 having, for example, a radial hole shape is provided between the load pressure side A and the control chamber 27, the throttle 28 having, for example, a size of about 0.4 mm, while The passage 29 has a size of about 0.5 mm.

The blocking element G, which functions as a seat valve, cooperates with the seat edge 14 of the main valve seat S via the conical face 31. The region also constitutes a flow regulating device (E), which is a sliding hole (15) and a blocking element (G) on the extension of the main valve seat (S) inside the insert (13). It consists of the cylindrical sliding protrusion 32 on the extension line of the conical surface 31 of (circle). This will be described later with reference to FIG. 6. The spring 22 is a light spring, that is, as shown in 36b of FIG. 7, the spring load F is rapidly reduced with respect to the deformation path s. In the known black / white drain valve according to the prior art, the spring provided at that position is a soft spring having the characteristic of a flat curve 37b, as shown by the dashed-dotted line in the figure. The load characteristic of the magnet 6 is adapted to the spring characteristic 36b of the light spring 22 of FIG. 3 so that the reproducible different positions of the plunger 24 can be precisely adjusted.

Hereinafter, the operation of the present embodiment will be described with reference to FIGS. 1 and 3.

In a state in which no current flows in the magnet 6, the light spring 22 keeps the pilot valve C in a blocked state. In the control room 27, the load pressure on the load pressure side A acts predominantly in the region of the blocking element G, which is a region larger than the region of the main valve seat S. The load pressure keeps the shut-off element G in the shown shut-off position, which is predominantly hermetic, as is the case with the pilot valve C. When the magnet 6 is operated by a predetermined current to cause the lowering operation to occur, the plunger 24 is moved upward so that the blocking member 26 is in an intermediate position from which the passage 29 exits. The prevailing pressure in the control chamber 27 is reduced so that the load pressure lifts the shutoff element G from the main valve seat S. The sliding portion 32 first cooperates with the sliding hole 15 to allow a small amount of pressurized fluid to flow out at first (in addition to the flow rate of the pressurized fluid flowing through the open pilot valve C). . As the blocking element G flows, it eventually reaches equilibrium. In this state, in response to a possible load pressure change, the pilot valve C is throttled to such an extent as to cause a specific open state or flow movement of the blocking element G. In addition, a predetermined amount of pressurized fluid flows out of the tank T at this position. By increasing the current flowing in the magnet 6, when the plunger 24 is positioned further upward, the blocking element G correspondingly has no overlap between the sliding portion 32 and the sliding hole 15 at last. Move until it is lost, and pressurized fluid flows out to a greater degree. If the current flowing in the magnet 6 further increases, the blocking element G finally moves to the full pass position. When the current decreases again, the blocking element G again performs a throttle action. If the current is interrupted, before the load pressure moves the blocking element G to the blocking position, the rigid light spring 22 first shuts off the pilot valve C and the plunger 24 follows this blocking movement. . The ramp function can thereby be controlled such that there is only a gradual increase or only a gradual decrease in flow towards the tank.

When the magnet 6 is excited in FIG. 4, the armature 20 of the magnet 6 presses the plunger 24 downward. The light spring 22 is supported on the stop joint 23 'inside the stop armature member 20', and the light spring 22 is connected to the head member of the plunger 24 to open the pilot valve C. 25) to bias upward. This means that in the state in which no current flows in the magnet 6, the load pressure of the 5a portion lifts the blocking element G from the main valve seat S so as to be in the full passing position. (G) is not shown in the full pass position.) In contrast to FIG. 3, when a current is applied to the magnet 6, it moves the plunger 24 toward the direction in which the pilot valve C is shut off. The magnet 6 has been modified to move downward (optionally using the auxiliary plunger 24). The other configuration of this drain valve V 'corresponds to that shown in Fig. 3, and the size and characteristics of the magnet 6 are also almost the same.

In both embodiments, the magnet 6 and the light spring 23 are each applied by the pressure of the current generated from the cross-sectional area of the passage 29 and acting on the plunger 24 without abrupt changes or sudden movements in the blocked state. It is designed to beat the losing force. This blocking load arises from the fact that the pressure prevailing in the control chamber 27 acts on all sides of the plunger 24 of the magnet 6.

Hereinafter, the operation of the present embodiment will be described with reference to FIGS. 2 and 4.

In the state where no current flows in the magnet 6, the light spring 22 moves the plunger 24 to the upper end position, so that the blocking element G takes the passing position. When a preselected current acts on the magnet 6, the plunger 24 moves over the force of the light spring 22, so that the blocking member 26 enters into the passage 29 of the blocking element G. And the control pressure of the control room 27 raises. And the blocking element G again moves towards the blocking position of the main valve seat S. FIG. The amount of pressurized fluid flowing out of the main valve seat S is throttled. In order to open or shut off the pilot valve more or less, the blocking element G can perform a flow movement. As the current acting on the magnet 6 increases, the plunger 24 moves further downward. The blocking element G moves further in the direction of the blocking position according to this movement, and the flow regulating device E is also activated just before reaching the last blocking position. When the maximum current is applied to the magnet 6, the blocking element G has a final blocking position in which the conical face 31 is sealed seated at the seat edge 14. When the current applied to the magnet 6 is reduced again, the flow rate of the outflowing pressurized fluid is reduced by the cooperation of the sliding piston portion 32 and the sliding hole portion 15 (FIG. 3) by the first of the blocking element G. Controlled through an open stroke. The unloading operation can be controlled by the ramp function in this way.

According to FIG. 5, the sliding piston attachment portion 32 extends directly to the conical surface 31 of the blocking element G. The sliding hole 15 starts from the sheet edge 14 at a predetermined distance by the extension 33. For the sake of convenience, an overlap U, which can be of a size less than 10% of the total opening stroke of the blocking element G, is present between the sliding piston portion 32 and the sliding hole portion 15 (see FIG. 5). ). This overlap U is defined, for example, by the stepped transition between the expansion 33 and the sliding hole 15 and the lower edge 34 of the sliding piston 32. A gap 35 is present in this area with a size corresponding to a standard sliding fit (for example 0.1 mm). Since the conical surface 31 cooperates with the seat edge 14 at the outer portion of the sliding piston portion 32, the conical surface 31 and the sliding piston portion 32 can be easily manufactured.

As shown in FIG. 6, for manufacturing reasons, the conical surface 31 of the blocking element G passes through the restricting portion 38, which is similar to the groove shape, so that the axial direct extension of the seat edge 14 occurs. It enters the sliding piston part 32 which cooperates with the sliding hole part 15 which forms a part. The overlap U may be slightly increased. And the gap 35 has a predetermined size.

FIG. 7 shows the spring characteristic 36a of the light spring 22 of the embodiment shown in FIG. 4 in contrast to the spring characteristic 37a of the soft spring typically used in the black / white drain valve.

Substantially the same kind of magnet 6 is used in both cases, and the necessary modifications are simple. A magnet 6 having the same structural size and slightly stronger than the conventional magnets used for known black / white drain valves is advantageously used for the drain valves V and V ', which have a ramp function. This is because it is suitable for the spring of (V, V '). However, the reason why the soft spring is used in the known black / white drain valve is as follows. That is, in the case of the connection mode in which the drain valve is cut off while no current flows in the magnet, it is possible to ensure that the spring merely resets the mass, while the drain valve is opened in the absence of current flow in the magnet. This is because in the connection mode, the spring only needs to define the pressure at which the drain valve opens without becoming a disturbing element during the shutoff stroke. On the other hand, in the drain valves V and V 'having a ramp function, the light spring cooperates with the magnet 6 to add various positions of the plunger to be reproduced in a stepwise or infinitely varying manner. Has a functional function.

The present invention provides a self-acting drain valve having a lamp function, which can control a lifting operation at a simple structure and at low cost, and thus has an advantage that it can be applied to a small stacker truck at a large cost without burden.

Claims (9)

It is arranged in the blocking direction on the main valve seat located between the load pressure on the load pressure side (A) and the drain pressure on the drain pressure side (B), and can be driven in the opening direction by the drain pressure, and in the blocking direction, the A blocking element (G) operable to be in a blocking position against the main valve seat and away from the main valve seat to open the main valve seat by a variable pressure difference between a drain pressure and a control pressure resulting from the load pressure ; A pilot valve (C) actuated by a magnet (6) and arranged in the control chamber of the blocking element (G) to control the magnitude of the control pressure; A throttle (28) in which the control chamber is located between the load pressure side (A); With a blocking member 26 of the pilot valve C, which is adjustable by a spring against the magnet, driven by a magnet against a spring acting in a blocking direction or in an opening adjustment or opening direction. In a stacker truck, a self-acting drain valve of an electrohydraulic lifting module, The spring is a spring 22 having a steep characteristic curve 36a, 36b to achieve the ramp function of the drain valve, The blocking element G and the main valve seat S form a flow regulating device E that depends on the amount of lift for the medium passing through the drain valve, The flow regulating device E includes a conical surface 31, a cylindrical sliding protrusion 32 that intrudes into the main valve seat S and the seat edge 14, and the seat from the seat. A cylindrical sliding hole portion 15 extending toward the drainage pressure side and cooperating with respect to a predetermined gap 35 beyond the initial lifting portion from the blocking position of the sliding element 32 and at least the blocking element G; Self-operating drain valve of the electrohydraulic lifting module, characterized in that. The method of claim 1, The throttle 28 is smaller than or equal in size to the passage 29 of the pilot valve C, The passageway (29) is a magnetically operated drain valve of the electrohydraulic lifting module, characterized in that it has a size corresponding to a hole having a maximum diameter of 0.6mm. The method of claim 1, The light spring 22 biases the plunger 24 having a substantially conical end in the blocking direction of the pilot valve C, The passage 29 of the pilot valve C is an axial hole of the blocking element E, The magnet (6) comprises a movable armature (20) adapted to act on the plunger (24) in the opening direction of the pilot valve (C). The method of claim 1, The light spring 22 biases the plunger 24 having a substantially conical end in the opening direction of the pilot valve C, The passage 29 is an axial hole of the blocking element E, And said movable armature (20) of said magnet (6) acts on said plunger (24, 24 ') in the opening direction of said pilot valve (C). The method of claim 1, The gap (35) has a standard sliding fit size, for example about 0.1 mm, the self acting drain valve of the electrohydraulic lifting module. The method of claim 1, The sliding hole 15 is a direct extension of the seat edge 14, A magnetically operated drain valve of an electrohydraulic lifting module, characterized in that a peripheral limiting portion (38) is provided between the conical surface (31) and the sliding projection (32) of the blocking element (G). The method of claim 1, The sliding hole 15 starts axially spaced apart from the sheet edge 14 and has a smaller inner diameter than the sheet edge 14, The conical surface 31 is characterized in that the electrohydraulic lifting is characterized in that it extends directly to the sliding attachment portion 32 whose outer diameter is less than the inner diameter of the seat edge 14 and the sliding hole 15. Self-acting drain valve on the module. The method of claim 1, Preferably an axial overlap U of less than 10% of the total opening stroke of the blocking element G is provided with the sliding part 32 and the sliding hole 15 at the blocking position of the blocking element G. Magnetically operated drain valve of the electrohydraulic lifting module, characterized in that provided between). The method according to any one of claims 1 to 8, With black / white drain valve, For the installation of the light spring 22 instead of the soft spring, the selective reduction of the cross-sectional area of the flow regulating device E and the passage 29 of the pilot valve C, and the proportional flow control action. And a valve component in accordance with the characteristics of the magnet (6) corresponding to the characteristics (36a, 36b) of the light spring (22).

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