EP2674533B1 - Electro-hydraulic control system - Google Patents

Description

The invention relates to an electro-hydraulic control system according to the preamble of claim 1.

From the technical information D7700 CAN, February 2011, the company HAWE Hydraulik SE, Streitfeldstraße 25, 81673 Munich / DE, especially page 2, an electro-hydraulic control system is known in which several 4/3-way proportional valve with a CAN direct drive be operated. These are, for example, proportional directional spool type PSL (for a hydraulic supply by a constant pump) and PSV (for a supply by a control pump) of the Applicant. For the operation of a programmable logic valve control is provided. These main control valves are used to control the direction of movement and optionally load-independent, stepless control of the speed of movement of hydraulic consumers, such as hydraulic cylinders. At least one main control valve or master control valve has a CAN actuator head and is connected via either two-core or four-core cable. The CAN bus has two wires (CAN-hi, CAN-lo). Two cores provide the operating voltage, eg 12 to 30 volts DC (U _bat ,, grounding). The control current for actuating the main control valve is applied at a dither frequency between about 40 to 100 Hz, preferably about 55 Hz, to pre-assemble overloads of the magnetic actuator, whereby the spool valve of the multi-way valve is continuously adjusted to a target volume flow to the connected hydraulic cylinder produce. The CAN bus is an asynchronous, serial bus system, whose common data transmission formats are the protocols CAN-open 2.0 A and B, and J1939, based on 11-bit or 29-bit address data, and transfer rates between about 100 kbit / s to about 1000 kbit / s are. A Plug and Play configuration can be used for the respective CAN node. The respective valve electronics may contain amplifier components. Such electro-hydraulic control systems or hydraulic valve manifolds, also according to EP 2 063 159 B1 , have been used successfully for years not only in cranes, but also in hydraulic excavators, wheel loaders, forestry equipment or other mobile equipment.

When using such tools, for example, depending on the consistency or nature of the tool processed with the tool, eg soil, feed, or the like, shows a phenomenon in that the steadily moving tool tends to settle, which Working time is inconveniently prolonged and hampered an efficient work process. In this case, the tool can both set when entering the good or when loosening from the good. Only the control of different or superimposed directions of movement of the constantly moving tool does not provide a satisfactory remedy.

From an article "Rüttelventil, For working with adhesive material", the journal O + P, Issue 3/2012, page 35 (available on the Internet at: www.vfmz.net/1211390 ), it is in mobile hydraulics, for example for construction machinery and Agricultural machinery known to use an additional control valve in at least one working line of a hydraulic consumer, with the irrespective of the control unit of the central control, for example, by pressing a button on the joystick a shaking function of the tool can be controlled. The control valve is equipped with appropriate electronics, whereby the frequency of the shaking function can be adjusted. The installation of an additional control valve is complex and expensive and can undesirably affect the function of the main control valve. Furthermore, a loss of power is due to the additionally used control valve, and the mutual coordination between the additionally built-in control valve and the main control valve and the basic function monitoring of the electro-hydraulic control system can be made more difficult.

In the generic electro-hydraulic control system according to EP 0 511 383 A1 be controlled by a controller, the actuating magnet of the two control valves Rectangle control flow signals volume flow fluctuations with activated shaking function, the same magnetic actuators that operate the control valves in normal operation with the shake function disabled. The shaking function is carried out with an operating mode in which only one actuation magnet is activated at a time, while the other is not. Thanks to a cross-connection of the two control valves but a volume flow pulse is introduced in this way, for example, in the piston-side chamber of the hydraulic cylinder, while from the piston rod side chamber, a volume flow pulse is discharged to the tank. Operating modes are adjustable via a selector switch, which for control current pulses define either a high amplitude at lower frequency, a middle amplitude at medium frequency, or a small amplitude at high frequency.

At one off US 2009/031891 A1 known electro-hydraulic control device volume flow fluctuations are generated exclusively by driving a controller of a control pump with activated shaking function. These volume flow fluctuations can pass through the hydraulic cylinder upstream control valve, if it is turned on in a working position.

At one off EP 1 361 312 A1 known electro-hydraulic control device four proportional control valves are connected in a bridge circuit, one of which is clocked open and closed when the shaking function is activated, whereas the other pair remains closed, so that only one pressure pulse is applied against a load on the cylinder.

The invention has for its object to improve an electro-hydraulic control system of the type mentioned using the skills of memory programming so that to save working time and improve the workflow a shaking of the tool in a cost effective and efficient way is possible.

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

Only by utilizing the memory programming capability provided without this, the shake function is self-controlled without additional hydraulic components to the main control valve by the memory programming receives at least one tool shake-function software, the activation of which the shaking function of the tool directly via the main control valve. In this way, when setting the tool in the machined Good the shaking function can be used to save working time and optimize the workflow. Updating the software or programming in this way or designing it from the beginning with a useful program section is inexpensive and easy. Since the usual dither frequency of the control flow of such main control valves is so high that the spool moves only steadily and harmoniously regulates the flow rate, it is useful for the Rüttelfunktion when activated Ripple function software for controlling the volume flow fluctuations control current signals in the solenoid actuator and / or a valve electronics of the main control valve with a low frequency between only 1.0 and about 30 Hz, preferably about 10 Hz, are applied. This frequency ensures an efficient shaking function, wherein the frequency range can be used, for example, adapted to the material to be processed, ie, the frequency can be variable. The volumetric flow fluctuations are expediently activated with activated shaking function by controlling current of the valve electronics or of the respective magnetic actuator with a frequency of between approximately 1.0 to approximately 30 Hz, preferably approximately 10 Hz, because a permanent application of current to the magnetic actuator could result in its overloading , To control the volume flow setpoint curve, however, the respective solenoid actuator or the valve electronics with a dither frequency between about 40 and 100 Hz, preferably clocked at about 55 Hz, with control current. From this relatively higher frequency compared to the frequency of the volume flow fluctuations results in a steady adjustment of the spool or a persistence of the spool in a set control position. By contrast, the low-frequency control current fluctuations cause jerky movements of the spool, starting from its respectively set control position or starting from the neutral position of the main control valve.

In doing so, e.g. When the chute function software is activated, the volume flow fluctuations are superimposed on a volume control set point of the main control valve, causing the tool to vibrate as it moves. Alternatively, even with the tool penetrated into the material, the shaking function could be controlled without interference with simultaneous movement of the tool, e.g. to relax the estate.

In an expedient embodiment, the bus is a CAN bus, and the main control valve is integrated with a CAN node in the CAN bus and designed for CAN direct drive. The field of application of this electrohydraulic control system, which has proven itself in practice diverse, is cost-effectively and efficiently expanded by the tool vibration function software, the CAN bus actuates the main control valve with activated Rütelfunction software so that for the at least one hydraulic cylinder volumetric flow fluctuations be controlled to assist the penetration or release of the tool, or even cause a loosening of the machined material before a subsequent, then speedy processing.

In an expedient case, the ripple function software is a program section of the central controller. Alternatively, the ripple function software could also be provided activatable in the CAN node or in a valve electronics.

Structurally simple, the Rütelfunktions software by a switch, a button or a push button on or near the tool-actuator, preferably on a handle of a joystick, optionally activated and deactivated. The deactivation could e.g. Time-dependent also programmed.

Alternatively, the shake-function software could be at least activated by a switch, button or push-button located at the central control, or in a control panel of a control console, e.g. in a keyboard or touchscreen, either by the operator.

Alternatively, an embodiment is expedient in which the ripple function software is automatically activated at least if the tool should tend to settle during work or has set itself. This state of the tool can be directly or indirectly via corresponding monitoring sensors detected and reported, for example, to the central control, which then at least automatically activates the ripple function software, and, for example, again automatically deactivated when normal moving tool again.

The shaking function can be performed by only one (or a group of similarly operating) hydraulic cylinder, which moves the tool in a certain direction of movement. Alternatively, to increase the efficiency of the shake function, it is possible to simultaneously control shaking functions directly in a plurality of main control valves for a plurality of hydraulic cylinders that move the tool in different directions of movement.

In an expedient embodiment, the main control valve is a multi-way slide, preferably a proportional slide or a black / white slide whose spool is adjustable by the at least one magnetic actuator. A proportional slider controls the direction of movement and controls the speed of movement, e.g. independent of load in accordance with the applied current of the magnetic actuator. A black / white slider works with magnets, which are switched between an activated and a de-energized condition. The spool is in accordance with an adjustment of the tool actuator is activated with jog function software disabled, for. steadily displaced, whereas discontinued when the rattle-function software is activated, i. shaking, preferably jerky and / or in opposite directions of adjustment over small strokes.

Furthermore, it is expedient if the frequency and / or the duration of time and / or the intensity of each volume flow fluctuation is or can be varied in order to be able to achieve an optimal work result during shaking.

Conveniently, the rattle-function software is stored, i. inscribed and programmed. Alternatively, the rattle-function software can also be transferred from a mobile data memory, for example to update given software, or to retrieve the ripple-function software only when needed. This can be done via a USP stick, a PC, or a diagnostic device on, for example, the central control.

Fig. 1

eine schematische Seitenansicht eines Gutbearbeitungsgerätes, wie eines Hydraulikbaggers mit einem elektrohydraulischen Steuersystem,

Fig. 2

schematisch ein Detail des elektrohydraulischen Steuersystems,

Fig. 3

als Blockschaltbild eine konkrete Ausführungsform eines elektrohydraulischen Steuersystems, als nicht beschränkendes Beispiel,

Fig. 4

eine Detailvariante,

Fig. 5

eine weitere Detailvariante, und

Fig. 6

ein Schaubild zum über das elektrohydraulische Steuersystem gesteuerten Volumenstrom über der Zeit.

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

Fig. 1

a schematic side view of a crop processing device, such as a hydraulic excavator with an electro-hydraulic control system,

Fig. 2

schematically a detail of the electro-hydraulic control system,

Fig. 3

as a block diagram of a concrete embodiment of an electro-hydraulic control system, as a non-limiting example,

Fig. 4

a detail variant,

Fig. 5

another detail variant, and

Fig. 6

a graph of over the electro-hydraulic control system controlled flow over time.

In Fig. 1 is a non-limiting example of eg a mobile implement a hydraulic excavator B schematically indicated in a side view, which has at least one Gutbearbeitungs tool W, such as a bucket, for processing a good G, and is equipped with an electro-hydraulic control system E. The hydraulic excavator B has a wheel 2 movable chassis 1 with a primary drive source and optionally a battery 3 and a cab 4 with a control panel 5 and an example manually adjustable tool actuator 6, such as a joystick on. In the control panel 5, a central control Z is provided, which is computerized and memory programmable. On board a control valve assembly V is further placed, which is controllable via the central controller Z and a bus C, for example a CAN bus, according to adjustments of the tool actuator 6. A cantilevered on the chassis 1 boom 7 is pivotable by means of at least one actuatable via the control valve assembly V hydraulic cylinder 8. On the boom 7, the tool W is articulated, for example, pivotally and by means of at least one further hydraulic cylinder 9, for example, a double-acting hydraulic cylinder, continuously movable (arrows 11).

Optionally, a sensor system can be provided which monitors at least the tool W directly or indirectly, for example sensors 10 in the articulation region of the arm 7 and in the articulation region of the tool W, wherein the sensor system 10 is also linked to the central control Z or the bus C. The electro-hydraulic control system E has tool ripple function software, with a shaking function F of the tool W is controllable, for example, indicated by the directional arrows 12, ie, to move the tool W in the respective direction of movement jerkily faster and slower, or only about to move short movement strokes back and forth, if the tool W in the processing of the goods G tend to settle or should be fixed.

According to Fig. 2 in the central control Z, the Rüttetfunktions software is stored as a program section S and retrievable or activated as needed. The control valve arrangement V includes, for example, a plurality of main control valves V1, V2, which are here combined in a block arrangement and connected together to a pressure source 14 and a return 15, wherein only the main control valve V1 to the hydraulic cylinder 9 guided working lines 16, 17 are shown. The pressure source 14 may be a fixed displacement pump or a variable displacement pump. The main control valves V1, V2 and the like are, for example, Proportional-way gate valves of the types PSL or PSV of the Applicant, which can optionally operate on the load-sensing principle. Each main control valve V1, V2 serves to control the direction of movement and to control the speed of movement of the hydraulic cylinder or of another hydraulic consumer.

The CAN bus C is for example two-wire and leads to a CAN mounting base 26 on the control valve assembly V. Further, the control valve assembly V is connected to a power supply 13 (two-wire) to the control valves via corresponding magnetic actuators (see Fig. 5 ) can be operated from the central control Z via the CAN bus C. Via a piston rod 18 of the hydraulic cylinder 9, for example, the tool W is moved in its articulation on the arm 7 in the direction of the arrows 11, 12. The boom 7 can be moved simultaneously.

Fig. 3 shows in a block diagram combined with a terminal block 27 main control valves V1, V2 as multipath proportional valve, each of which is connected to a pressure line 28 and a return line 29, and from which the working lines 16, 17 to the respective hydraulic cylinder, eg the hydraulic cylinder 9 lead , In the embodiment in FIG Fig. 3 it is 4/3-proportional way slider. Alternatively, the respective main control valve V1, V2 could be a 2/2, 3/2, 3/3-way control valve. In Fig. 3 are installed as magnetic actuators proportional solenoids 31a, 31b. Alternatively, black and white magnets could be installed instead of proportional solenoids.

The main control valve V1 in Fig. 3 has a spool 21 which is continuously adjustable in a block housing by the proportional magnets 31a, 31b between different switching positions. The proportional solenoids 31a, 31b could actuate the spool 21 directly. However, to get along with moderate magnetic forces, are in Fig. 3 optionally pressure pilot controls 30a, 30b are provided for one adjustment direction of the piston slide 21, ie, each proportional solenoid 31a, 31b controls a pressure pilot control 30a, 30b, which in turn adjusts the slide piston 21. The magnets of the main control valve V1, which may contain integrated valve electronics, are connected to a CAN node in the CAN bus C of FIG

Fig. 1 and 2 incorporated. A spring assembly 32 serves to center the spool 21 in the neutral position shown, in which the working lines 16, 17 as well as the pressure and return lines 28, 29 are shut off. Furthermore, a feed regulator 33 (optional) which picks up the respective load pressure is provided. The proportional solenoids 31a, 31b, optionally combined with the valve electronics, form the at least one magnetic actuator 22 of the main control valve V1. In the CAN node 23 or adjacent to this, a displacement transducer 30 is optionally provided and connected to the CAN bus C to monitor the respective position of the spool 21 can.

Fig. 4 schematically shows the control panel 5 or on a handle 19 of the tool-actuator (joystick) a push button 20, a button, a switch, or the like., With which the shaking function F can be activated and optionally also deactivated. The program section S, which represents the Rüttelfunktions software is included or stored in the central control Z, ie either provided from the outset or subsequently programmed.

In the detail variant in Fig. 5 the integration of the main control valve V1 in the CAN bus C is shown with the CAN node 23 to which the solenoid actuator 22 is connected to actuate the spool 21. As an alternative, the program section S corresponding to the ripple function software is provided either in the CAN node 23 or in a valve electronics 24 and activated, for example via the CAN bus C and the central control Z.

Fig. 6 shows in a diagram the superposition of the shaking function F with a volume flow setpoint curve 25 of a desired volume flow Qs. The volume flow is plotted on the vertical axis Q, while time is plotted on the horizontal axis t. The volumetric flow setpoint curve shown in this embodiment parallel to the time axis t represents a certain continuous movement speed of the tool W. Upon activation of the ripple function software, the curve 25 is superimposed on volume flow fluctuations Q 'whose frequency f, respective time duration w and / or respective intensity or amplitude a are appropriately varied. The volumetric flow fluctuations Q in the left half of Fig. 6 represent volume flow increases compared to the setpoint curve 25, while represent in the right part of the figure, the volume flow fluctuations Q 'increases and decreases compared to the volume flow setpoint curve 25.

The volumetric flow fluctuations Q 'are expediently activated with activated shaking function F by control current application of the valve electronics 24 or of the respective magnetic actuator with a frequency f between about 1.0 to about 30 Hz, preferably about 10 Hz, because a permanent current applied to the magnetic actuator Overload result could. To control the volume flow setpoint curve 25, however, the respective solenoid actuator or the valve electronics 24 is clocked at a dither frequency between about 40 and 100 Hz, preferably at about 55 Hz, with control current. From this relatively higher frequency compared to the frequency f of the volume flow fluctuations Q 'results in a steady adjustment of the spool 21 or a persistence of the spool 21 in a set control position. By contrast, the low-frequency volume flow fluctuations Q 'cause jerky movements of the spool 21, starting from its respectively set control position or starting from the neutral position of the main control valve V1, V2.

In the embodiments shown, when the shaking function is activated, the tool W is moved in a direction of movement by the volume flow fluctuations, for example the direction of movement monitored by the hydraulic cylinder 9. However, it is quite possible to simultaneously apply a plurality of hydraulic cylinders with volume flow fluctuations in order to perform the shaking function in several directions of movement of the tool W, such as in Fig. 1 indicated by the further directional arrows for the Rüttelfunktion the hydraulic cylinder 8. In this case, the tool W would be moved about the articulation on the boom 7 in the shaking function, and at the same time to the articulation of the boom 7 in the chassis 1 to intensify the effect of the shaking function.

Claims (12)

1. Electrohydraulic control system (E) for at least one hydraulically movable material processing tool (W), in particular of a hydraulic dredger (B), with a computerized, memory-programmable central control (Z), to which a mechanically adjustable tool actuator (6) is connected, and which is connected via a bus (C) with at least one magnetic actuator (22) of at least one main control valve (V1, V2) of at least one hydraulic cylinder (8, 9) each for moving the tool (W), wherein tool vibration-function software is stored in the memory programming such that it can be activated as required, by means of which volume flow fluctuations (Q') for the hydraulic cylinder (8, 9) for carrying out a vibration-function (F) of the tool (W) can be controlled directly in the main control valve (V1, V2) by means of the magnet actuator (22),
   characterised in that
   the magnet actuator (22) of the main control valve (V1, V2) is operable for moving or holding the tool (W) with control current signals having a dither frequency between approximately 40 Hz and approximately 100 Hz when the vibration-function is deactivated and with control current pulses having a lower frequency (f) between 1.0 and approximately 30 Hz, preferably around approximately 10 Hz, when the vibration-function is activated.
2. Electrohydraulic control system according to claim 1,
   characterised in that
   the dither frequency is about 55 Hz.
3. Electrohydraulic control system according to claim 1,
   characterised in that
   the control current pulses are superimposed on the control current signals applied with the dither frequency when the vibration-function is activated.
4. Electrohydraulic control system according to claim 1,
   characterised in that
   the bus (C) is a CAN bus, and in that the main control valve (V1, V2) is integrated into the CAN bus with a CAN node (23) and is configured for CAN direct control.
5. Electrohydraulic control system according to claim 1,
   characterised in that
   the vibration-function software is a program section (S) written or loaded in the central control (Z) or a CAN node (23) or a valve electronics (24) in the main control valve (V1, V2).
6. Electrohydraulic control system according to claim 1,
   characterised in that
   the vibration-function software can be selectively activated and deactivated by a switch, a button or a push-button (20) on or near the tool actuator (6), preferably a handle (19) of a joystick.
7. Electrohydraulic control system according to claim 1,
   characterised in that
   the vibrating function software can be selectively activated and deactivated by a switch arranged on the central control (Z), a key or a push-button (20), or in a control panel of a control board (5), e.g. in a keyboard or a touch screen.
8. Electrohydraulic control system according to claim 1,
   characterised in that
   the vibration-function software can automatically at least be activated via a sensor system (10) directly or indirectly monitoring the tool (W).
9. Electrohydraulic control system according to at least one of the preceding claims,
   characterised in that
   several hydraulic cylinders (8, 9) can be controlled simultaneously and directly in several main control valves (V1, V2) for different directions of movement of the tool (W).
10. Electrohydraulic control system according to claim 3,
    characterised in that
    volume flow fluctuations (Q') controlled with activated vibration-function software can be superimposed on a volume flow target value (Q_S) of the main control valve (V1, V2).
11. Electrohydraulic control system according to claim 1,
    characterised in that
    the main control valve (V1, V2) is a multi-way slide valve, preferably a proportional slide valve or a black/white slide valve, the slide piston (21) of which is continuously adjustable when the vibration-function software is deactivated in accordance with an adjustment of the tool actuator (6), and in that, when the vibration-function software is activated, the slide piston (21) is non-continuously adjustable, preferably jerky and/or in opposite actuating directions.
12. Electrohydraulic control system according to claim 10,
    characterised in that
    the frequency (f) and/or the duration (w) and/or the intensity (a) of each volume flow fluctuation (Q') is/are variable.

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