EP1686268B1 - Hydraulic control device - Google Patents

Description

The invention relates to a hydraulic control device specified in the preamble of claim 1 Art.

Such hydraulic control devices are used, for example, in stationary cranes or mobile cranes and in other hoists with multiple components to be moved in order to control the working speed and direction of at least one hydraulic consumer via the directional control valve. As a pressure source, e.g. a control pump, the flow rate is adjusted by means of the load pressure-dependent control pressure in the load pressure control circuit to the respective needs. However, a regulating pump feeds a base pressure between 15 and 30 bar, even in a regulated state. In an emergency stop operation of the control device while the control pump is still adjusted when the directional control valve is still adjusted; However, the basic pressure may still be sufficient to adjust over the directional control valve, the hydraulic consumer, which can lead to a dangerous situation.

From DE 43 24 177 A known hydraulic control device includes in the emergency stop shutdown system designed as a 3/2-slide solenoid switching valve emergency stop valve, which is connected to the load pressure control circuit and the pressure signal that adjusts an isolation valve between a passage position and a shut-off. The isolation valve is a 5/2-way valve between the pressure source and the supply line and also monitors the connection of the load pressure control circuit to the pressure source, eg the control connection of the control pump. In normal operation, the emergency stop solenoid switching valve is energized so that it holds the isolation valve in the passage position in which the pressure source to the supply line and the load pressure control circuit are connected to the control port. In emergency stop, the emergency stop solenoid valve is de-energized to relieve the pilot pressure of the isolation valve to the return, so that the isolation valve goes to the shut-off position by its spring and disconnects the pressure source from the supply line and relieves the control port to the return. In this case, the spring chamber of the separating valve is constantly connected to the return, so that the separating valve does not switch unintentionally or reliably remains in the passage position during normal operation. The well-known emergency stop system is complex, builds big and is expensive. In addition, if necessary, the maximum flow rate is independent of pressure limits.

Further prior art is contained in DE 199 04 616 A and DE 44 20 459 A ,

From the DE 4 420 459 A known hydraulic control device, the control device according to the invention differs in that the separating valve is biased by a spring in the blocking position and in that it is a 2/2 - wegeventil.

The invention has for its object to form a hydraulic control device of the type mentioned with a cost-effective, structurally simple and functionally reliable emergency stop shutdown system.

The stated object is achieved with the features of claim 1.

The two 2/2-way valves (a solenoid valve and a spring-pressure-controlled valve) are structurally simple, inexpensive and compact. In normal operation, the isolation valve is not held by the emergency stop solenoid valve in the passage position, but on the basis of the delivery pressure of the pressure source derived pilot pressure. The emergency stop solenoid valve is energized in normal operation and in the shut-off position, so that the pilot pressure, which acts on the isolation valve to the passage position, only has to overcome the force of the spring of the isolation valve. The permanent connection of the spring chamber to the return prevents the isolation valve from accidentally shutting off or throttling. In emergency stop the emergency stop solenoid valve is de-energized and switched to its passage position, so that the then acting parallel to the spring control pressure reliably adjusts the shut-off position of the separating valve and holds. The diaphragm device between the spring chamber and the return allows a permanent discharge of pressure medium, without endangering the shut-off position of the separating valve. In a recent switch to normal operation can be avoided by the diaphragm device, an undesirable sudden sudden switching (pressure surge) of the isolation valve.

In a simple embodiment, the diaphragm device may include a nozzle. However, since a nozzle can discharge more pressure medium at high pressure than at lower pressure, no constant switching behavior of the separating valve would be ensured. Therefore, in an advantageous embodiment, the aperture device a two-way flow regulator, the pressure-independent setting a predetermined pressure medium rate, thus ensuring a uniform switching behavior. The two-way flow regulator improves operational safety, because the predetermined pressure medium rate can be matched exactly to the operating conditions of the hydraulic control device. It may be useful if the two-way current controller is adjustable.

In an expedient embodiment, the pressure medium rate is set to about 0.3 to 0.5 l / min.

In a further advantageous embodiment, a commercially available, available in various specifications lowering brake valve, preferably even a screw-Senkbremsventil used for cost reasons as a two-way flow regulator.

The lowering brake valve may include an inlet side movable against the force of a spring orifice piston with at least one smaller inlet aperture and at least one larger drain aperture. With the drain aperture, a stationary control edge acts in such a way that the outflow cross section from the drain aperture is continuously reduced with increasing inlet pressure. In this way, the same pressure medium rate is always set pressure-independent.

The emergency stop shutdown system is expediently used when the pressure source is a regulating pump controlled from the load pressure control circuit. In an emergency stop situation, the control pressure for the control pump can either be held or relieved in any way to return.

Alternatively, however, the pressure source could also be a constant-displacement pump, which, for example, cooperates with a non-pressurized circulation system or is switched off in the event of an emergency stop.

In order to damp vibrations in the system as quickly as possible or to prevent their occurrence, it is expedient to provide a hydraulic damping device between the load pressure control circuit and the control connection of the pressure source.

Finally, it is convenient to incorporate the entire emergency stop system with the shutter in an input section housing, conveniently in an input section housing e.g. for a control pump.

Fig. 1

ein Blockschaltbild einer Eingangs-Sektion einer hydraulischen Steuervorrichtung,

Fig. 2

ein in Fig. 1 symbolisch dargestelltes Detail als Blockschaltbild, und

Fig. 3

einen Achsschnitt eines Senkbremsventils, wie es in den Fig. 1 und 2 verwendet sein kann.

Reference to the drawings, embodiments of the subject invention will be explained. Show it:

Fig. 1

a block diagram of an input section of a hydraulic control device,

Fig. 2

a in Fig. 1 symbolically represented detail as a block diagram, and

Fig. 3

an axial section of a lowering brake valve, as in the Fig. 1 and 2 can be used.

A hydraulic control device S in Fig. 1 serves with a pressure source P and a return R via a multi-way control valve W for direction and speed control of at least one hydraulic consumer V. The pressure source P is for example a control pump, with a control connection LS. Alternatively, the pressure source P could be a constant pump, which is combined, for example, with a pressure-free circulating system, which is controlled via the control connection LS. A pressureless circulation system could also be associated with the control pump 8.

In an input section E of the hydraulic control device S, an emergency stop system N is contained, for example in a single housing block, on or in which the individual components are combined.

The pressure source P is connected to a pressure line 1, which can be connected by a separating valve T optionally with a supply line 2 or disconnected therefrom.

The supply line 2 leads to the at least one multi-way control valve W, which is connected to a return line 3 to the return R. In the input section E, a return line 4 is also connected to the return R. Pressure limiting valves 5 between the pressure line 1 and the return line 4 limit the system pressure.

At a branch 6 of the pressure line 1 branch control lines 7, 8 to the separating valve T (a 2/2-way valve with pressure pilot 9 against the force of a spring 14). The control line 7 leads to the pressure pilot control 9 of the separating valve T, with which the separating valve T from the shut-off position shown in the passage position can be switched (pressure line 1 connected to the supply line 2). In the control line 8, an emergency stop solenoid valve M is provided between the branch 6 and a spring chamber 10 of the separating valve T, expediently a 2/2-solenoid switching valve by a switching magnet 12 from the set by a spring 11 passage position in a Locking position is adjustable (possibly with pressure pre-control). From the spring chamber 10 of the isolation valve T, a discharge line 17 leads via a filter 15 to a diaphragm device B, for example a two-way flow regulator 16, which is connected on the output side via a discharge line 17 'to the return line 4.

The diaphragm device B is in the simplest case a nozzle. However, the preference is given to a two-way flow regulator 16 which maintains a predetermined pressure medium rate independently of pressure.

Part of the hydraulic control device S may further be a load pressure control circuit L, which leads in the input section E to the port LS, in which case a hydraulic damping device D is provided, consisting of a Dämpfdrossel 20 and two mutually opposite check valves 18, 19 and a throttle 21 exists.

Further, a 2/2-solenoid switching valve 23 may be provided to relieve the control pressure at the port LS, for example, in emergency stop, wanted to return R.

In normal operation, the emergency-off solenoid switching valve M is energized and in the shut-off position, so that the spring chamber 10 of the separating valve T receives no control pressure from the control line 8. The isolation valve T is provided by the control pressure in the control line 7 on the pilot side 9 in the passage position and held in this, so that the pressure line 1 is connected to the supply line 2. The spring chamber 10 is relieved via the diaphragm device B to the return. The 2/2-solenoid switching valve 23 is also energized and in the shut-off, so that at the port LS load pressure-dependent control pressure prevails, with the example, the delivery rate of the pressure source P is adapted to the needs.

In the event of an emergency stop, the emergency-off solenoid switching valve M is de-energized if the multi-way control valve W is still deflected, and is moved into the open position by the spring 11 (FIG. Fig. 1 ) adjusted. The spring chamber 10 receives via the control line 8 control pressure, so that the separating valve T is adjusted by this control pressure and the force of the spring 14 in the shut-off position and held in this. The diaphragm device B, ie the two-way flow regulator 16, can only a predetermined pressure medium flow rate, for example between 0.3 and 0.5 l / min, so that the separating valve T remains in the shut-off position and still in the spring chamber 10 in addition to the force of Spring 14 only a predetermined pressure prevails. At the same time, if present, the 2/2-solenoid switching valve 23 can also be de-energized, and take the passage position, so that the control pressure at the port LS to return R is reduced.

Is later switch back to normal operation, then the emergency stop solenoid switching valve M and, if present, 2/2-solenoid switching valve 23 energized and adjusted in their shut-off, so that the isolation valve T, the pressure line 1 again with the Supply line 2 connects and at connection LS control pressure is built up.

Fig. 2 illustrates as a block diagram the embodiment of the two-way current controller 16 of Fig. 1 which is disposed between the spring chamber 10 and the return R. The two-way flow regulator 16 has a smaller inlet aperture 24 in the drain line 17. Upstream of the inlet panel 24, a control line 25 branches to the closing side of a 2/2 control valve 27 from. Downstream of the inlet orifice 24, a further control line 26 branches off to the control side of the 2/2 control valve, at which a control spring 33 also acts. In the 2/2 control valve 27, a larger than the inlet aperture 24 drain aperture 36 is provided, the outflow cross section is reduced in accordance with the pressures in the control line 25, 26 (in the manner of a pressure balance) starting from a maximum size, such that in the drain line 17 'outflowing pressure medium rate remains constant. This two-way flow regulator 16 may be formed by various hydraulic components, or is suitably a commercial Senkbremsventil SB according to Fig. 3 , which is designed here as a screw-Senkbremsventil.

The lowering brake valve SB has an outer screw-in housing 28 with a rotary handle 29, an external thread 30 and a peripheral seal 31. In the outer housing 28, where the drain line 17 is connected, a stationary control edge 37 is formed. In the outer housing 28, a diaphragm piston 32 is slidably guided, which is loaded by the control spring 33 in the direction of a stop 39. The control spring 33 is supported in the outer housing 28 on a spring abutment 38. The drain line 17 from the spring chamber 10 opens in the upper open end of the outer housing 28, i. where the orifice piston 32 has at least the smaller inlet orifice 24. Further, in the orifice piston 32 at least one drain aperture 36 is formed, which cooperates with the control edge 37. The higher the inlet pressure (the pressure gradient across the inflow orifice 24), the further the orifice piston 32 is displaced against the control spring 33, and the smaller the outflow cross-section of the drainage orifice 36, which is increasingly throttled by the control edge 37.

Claims (9)

1. Hydraulic control device (S) for at least one hydroconsumer (V), of which at least one working line is to be connected via a multi-way control valve (W) with a pressure source (P) and a return system (R), the hydraulic control device (S) comprising a load pressure pilot circuit (L) and an emergency shutdown system (N) which comprises between the pressure source (P) and a supply lie (2) extending to the multi-way control valve (W) a separating valve (T) which is pilot pressure controlled at least towards a through flow position and is spring actuated towards a blocking position, as well as a solenoid switching valve (M) between the pressure source (P) and the separating valve (T), wherein a spring chamber (10) of the separating valve (T) is connected with the return system (R), and wherein the solenoid switching valve (M) is a 2/2 multi-way valve which is arranged between the pressure source (P) and the spring chamber (10) of the separating valve (T), wherein the separating valve (T) is a 2/2 multi-way valve, the pilot pressure opening side (9) provided for adjusting the through flow position is permanently connected with the pressure source (P), and wherein at least one aperture assembly (B) is provided between the spring chamber (10) and the return system (R).
2. Hydraulic control device according to claim 1, characterised in that as the aperture assembly (B) between the spring chamber (10) and the return system (R) a two-way flow regulator (16) is provided by which a predetermined pressure medium flow rate can be adjusted independent from the pressure situation.
3. Hydraulic control device according to claim 2, characterised in that the pressure medium flow rate is adjusted to about 0.3 to 0.5 l/min.
4. Hydraulic control device according to claim 2, characterised in that the two-way flow regulator (16) is an off the shelf lowering braking valve (SB), preferably a screw-in lowering braking valve cartridge.
5. Hydraulic control device according to claim 4, characterised in that the lowering braking valve (SB) contains an aperture piston (32) having at least a smaller supply aperture (24) and at least a larger discharge aperture (36), the aperture piston (32) being displaceable from a supply side counter to the spring of a force (33), and that a stationary control edge (37) is co-acting with the discharge aperture (36) such that the discharge cross-section out of the discharge aperture (36) is decreased with increasing supply pressure.
6. Hydraulic control device according to at least one of claims 1 to 5, characterised in that the pressure source (P) is a rule pump which is ruled by pilot pressure from the load pressure pilot circuit (L).
7. Hydraulic control device according to at least one of claims 1 to 5, characterised in that the pressure source (P) is a constant discharge pump.
8. Hydraulic control device according to at least one of claims 1 to 7, characterised in that a hydraulic damping device (T) is provided between the load pressure pilot circuit (L) and the pressure source (P), the hydraulic damping device (D) containing a damping throttle (20) and two check valves (18, 19) blocking in opposite flow directions and respectively deviating the damping throttle (20).
9. Hydraulic control device according to at least one of the preceding claims, characterised in that the emergency shutdown solenoid switching valve (M), the separating valve (T) and the aperture assembly (B) are arranged in an entry section housing block (E) of the hydraulic control device (S), which, preferably, is supplied from the rule pump (P).

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