Hydrostatic drive system with generation of a shaking function of a hydraulic consumer

Abstract

Hydrostatic drive system with at least one hydraulic consumer (6; 8; 10) which is controlled by means of a control directional valve (20), wherein the control directional valve (20) is electronically controlled and is operatively connected to an electronic control device (25) for actuation, wherein the electronic control device (25) is connected to a control element (26) designed as a joystick and the electronic control device (25) generates an actuation signal (31) for actuating the control directional valve (20) upon actuation of the control element (26), wherein an additional control element (35) is provided which is connected to the electronic control device (25), and upon actuation of which additional control element a shaking function of the consumer (6; 8;10), wherein the electronic control device (25) generates an additional actuation signal (37) upon actuation of the additional control element (35), wherein the electronic control device (25) generates a control signal (40) which actuates the control directional valve (20) upon simultaneous actuation of the control element (26) and the additional control element (35), in which control signal the additional actuation signal (37) is superimposed on the actuation signal (31), wherein the additional control element (35) is arranged on the control element (26), characterized in that the amplitude and / or the frequency of the additional actuation signal (37) can be controlled with the additional control element (35), wherein the additional control element (35) is designed as a rotary wheel (36) which is arranged on the control element (26) designed as a joystick, wherein the additional control element (35) can be controlled with a thumb of a hand of an operator operating the control element (26) can be operated.;

Description

[0001] The invention relates to a hydrostatic drive system with at least one hydraulic consumer which is controlled by means of a control directional valve, wherein the control directional valve is electronically controlled and is operatively connected to an electronic control device for actuation, wherein the electronic control device is connected to a control element designed as a joystick and the electronic control device generates an actuation signal for actuating the control directional valve upon actuation of the control element, wherein an additional control element connected to the electronic control device is provided, upon actuation of which a shaking function of the consumer can be generated, wherein the electronic control device generates an additional actuation signal upon actuation of the additional control element,wherein the electronic control device generates a control signal controlling the control directional valve upon simultaneous actuation of the control element and the additional control element, in which the additional actuation signal is superimposed on the actuation signal, wherein the additional control element is arranged on the control element.

[0002] In mobile, self-propelled machines, particularly construction machines such as excavators, wheel loaders, and telescopic loaders, there is a need to implement a shaking function on hydraulic consumers in order to execute a shaking movement of the consumer through rapid movements of the hydraulic consumer. In a machine designed as an excavator, such a shaking function is desired on a bucket cylinder that actuates an excavator bucket and / or on a dipper arm cylinder that actuates a dipper stick. In a machine designed as a wheel loader, such a shaking function is desired on a bucket cylinder that actuates a shovel. The shaking function can be used, for example, to distribute material picked up in the work equipment formed by the bucket or shovel over a large area, or to loosen material adhering to the work equipment.

[0003] In drive systems with electronically controlled control directional valves for controlling consumers, the shaking function on a specific consumer is carried out by the operator by quickly and jerkily deflecting and thus quickly and jerkily actuating a control element, for example a control lever or a joystick, which, when actuated, issues a control command to an electronic control device and generates an actuation signal from the electronic control device to actuate the control directional valve controlling the consumer. Through the quick and jerky movements of the control element, the operator specifies the shaking frequency and the shaking amplitude of the consumer actuated by means of the control element. This impedes the operator's ability to operate other functions and other consumers.Typically, in such drive systems, where the control valves are electronically controlled depending on the actuation of the control element, the functions are damped. When the control element is actuated, the electrical signal of the control element is influenced by a filter device and / or a damper device to generate the actuation signal that activates the control valve. Therefore, with a harmoniously tuned machine, the shaking function can only be achieved by severe over-exaggeration and over-control, requiring the operator to deflect the control element accordingly far and quickly with jerky movements.

[0004] It is already known to automatically change the damping and thus the influence of the electrical signal of the control element during shaking in drive systems with electronically controlled control directional valves for controlling consumers. However, this requires that the intention to shake and thus the operator's request can be reliably detected and recognized by an electronic control device that activates the control directional valves. EP 1 740 778 B1 discloses a drive system in which, for a shaking function of a consumer, the influence of the electrical signal of the control element is changed by changing the filter properties of a filter element. The intention to shake is recognized by repeatedly actuating the control element quickly. The shaking of the consumer movement is also generated by jerky and rapid movements of the control element by the operator.

[0005] In existing machines, the shaking function can only be achieved by jerky movements of the control element by the operator. This requires considerable experience on the part of the operator to appropriately specify the frequency and amplitude of the actuator's shaking movement. Generating the shaking function of a hydraulic actuator by rapid and jerky movements of the control element is perceived as uncomfortable by the operator.

[0006] From EP 2 674 533 B1 a generic hydrostatic drive system with the features of the preamble of patent claim 1 is known.

[0007] US 6 757 992 B1 discloses a hydrostatic drive system in which a shaking function of a hydraulic consumer is activated and deactivated with a switch on an operating lever.

[0008] EP 1 361 312 A1 discloses a hydrostatic drive system in which a shaking function of a hydraulic consumer is activated and deactivated with a button on a joystick.

[0009] DE 10 2007 030 609 A1 discloses a hydrostatic drive system in which a shaking function of a hydraulic consumer can be controlled by pressing a button on a joystick.

[0010] US 6 425 729 B1 discloses a telescopic loader with a telescopic arm, in which the raising and lowering of the telescopic arm and the forward and backward tilting of a tool holder at the front end of the telescopic arm can be controlled with a joystick and the extension and retraction of the telescopic arm can be controlled with a rotary wheel arranged on the joystick.

[0011] The present invention is based on the object of providing a drive system of the type mentioned at the outset, in which the shaking function of a consumer can be achieved in a convenient manner.

[0012] This object is achieved according to the invention in that the amplitude and / or the frequency of the additional actuation signal can be controlled with the additional control element, wherein the additional control element is designed as a rotary wheel which is arranged on the control element designed as a joystick, wherein the additional control element can be actuated with a thumb of a hand of an operator operating the control element.

[0013] According to the invention, the shaking function is thus not generated by jerky and rapid movements of the control element, but rather by additional actuation of an additional control element. To control the control directional valve, a control signal is generated that is composed of the actuation signal of the actuated control element and the additional actuation signal of the actuated additional control element, with the additional actuation signal being superimposed on the actuation signal. Thus, according to the invention, the shaking function is not implemented as an independent function generated by jerky movements of the control element, but as an additional function that can be activated by actuation of the additional control element and is superimposed on the normal function during normal actuation of the control element.For the shaking function, the shaking movement of the consumer generated by the additional control element is superimposed on the normal movement of the consumer specified by the normal operation of the control element. This results in a convenient operation of the shaking function, as the control element can be operated normally and the shaking function is triggered with the superimposed shaking movement by actuating the additional control element. This creates a shaking function in which the shaking function allows the operator of the working machine to execute shaking movements of the consumer harmoniously and intuitively. The shaking function can be triggered in an ergonomically favorable manner by simply actuating the additional control element, without jerky and rapid actuation of the control element.

[0014] According to the invention, the additional control element is arranged on the control element. This enables ergonomic operation of the shaking function, which is implemented as an additional function.

[0015] According to the invention, the amplitude and / or frequency of the additional actuation signal can be controlled with the additional control element. This makes it easy for the operator to control the amplitude and / or frequency of the superimposed shaking movement. The amplitude and / or frequency of the superimposed shaking movement can thus be easily and optimally adjusted to the mechanical properties of the consumer, for example, the inertia, stiffness, and natural frequency of the consumer.

[0016] Advantageously, the additional actuation signal is designed as a square wave. A square wave that jumps back and forth between two values ​​can easily be used to create a superimposed shaking movement of the consumer.

[0017] According to the invention, the additional control element is designed as a rotary dial. A rotary dial makes it possible to control the amplitude and / or frequency of the additional actuation signal and thus the superimposed shaking movement in a simple and ergonomic manner.

[0018] According to the invention, the additional control element can be actuated with the thumb of the hand of an operator operating the control element. The operator can thus control the normal movement of the consumer by deflecting the control element with the hand grasping the control element, and with the thumb of this hand, control the additional control element for the superimposed shaking movement of the consumer in an ergonomically favorable and simple manner. For this purpose, the additional control element is preferably designed as a thumbwheel.

[0019] The invention provides a method for generating a shaking function of a hydraulic consumer of a hydrostatic drive system, which is controlled by means of an electronically controlled control directional valve, wherein a control element is provided and upon actuation of the control element an actuation signal for controlling the control directional valve is generated, wherein an additional control element is provided, upon actuation of which the shaking function of the consumer is generated by generating an additional actuation signal, wherein upon simultaneous actuation of the control element and the additional control element a control signal controlling the control directional valve is generated, in which the additional actuation signal is superimposed on the actuation signal.

[0020] According to the invention, the shaking function is thus not generated by jerky and rapid movements of the control element, but by additional actuation of an additional control element. To control the control directional valve, a control signal is generated that is composed of the actuation signal of the actuated control element and the additional actuation signal of the actuated additional control element, by superimposing the additional actuation signal on the actuation signal. In the method according to the invention, the shaking function is thus not implemented as an independent function generated by jerky movements of the control element, but as an additional function that can be activated by actuating the additional control element and is superimposed on the normal function during normal actuation of the control element.For the shaking function, the shaking movement of the consumer generated by the additional control element is superimposed on the normal movement of the consumer specified by the normal operation of the control element. This results in a convenient operation of the shaking function, as the control element can be operated normally and the shaking function is triggered with the superimposed shaking movement by actuating the additional control element. This creates a shaking function in which the shaking function allows the operator of the working machine to execute shaking movements of the consumer harmoniously and intuitively. The shaking function can be triggered in an ergonomically favorable manner by simply actuating the additional control element, without jerky and rapid actuation of the control element.

[0021] The amplitude and / or frequency of the auxiliary actuation signal are determined by actuating the auxiliary control element. If the amplitude and / or frequency of the auxiliary actuation signal can be changed depending on the actuation of the auxiliary control element, the operator can easily adjust the superimposed shaking function to the mechanical properties of the consumer, such as the consumer's inertia, stiffness, and natural frequency, by actuating the auxiliary control element accordingly.

[0022] Further advantages and details of the invention are explained in more detail with reference to the embodiment shown in the schematic figures. Fig. 1 a mobile work machine with a drive system of the state of the art, Fig. 2 a hydraulic circuit diagram of the drive system of the state of the art, Fig. 3 a diagram illustrating the inventive shaking function of a consumer in the drive system.

[0023] In the Fig. 1 shows a mobile work machine 1 with a hydrostatic drive system. In the illustrated embodiment, the work machine 1 is designed as an excavator with an undercarriage 2 and an uppercarriage 3 that can rotate relative to the undercarriage 2. A pump 4 is arranged in the uppercarriage 3 and supplies the consumers of the hydrostatic drive system with pressure medium. In the illustrated embodiment, the consumers of the hydrostatic drive system are a boom cylinder 6 that actuates a boom 5, a dipperstick cylinder 8 that actuates a dipperstick 7, and a bucket cylinder 10 that actuates an excavator bucket 9.

[0024] In the Fig. 2 shows a circuit diagram of the hydrostatic drive system of the working machine 1.

[0025] The pump 4 sucks pressure medium from a container 16 via a suction line 15 and delivers the pressure medium into a delivery line 17, to which control valves are connected for controlling the direction and speed of movement of the consumers 6, 8, 10. In the Fig. 2 shows only one control valve 20 controlling the bucket cylinder 10. The control valve 20 is connected to the delivery line 17, to a container line 21 leading to the container 16, and to consumer lines 22, 23 leading to the bucket cylinder 10. The control directional valve 20 is designed as a proportional valve that throttles in intermediate positions and has a middle position designed as a neutral position 20a, in which the connection of the consumer lines 22, 23 to the delivery line 17 is blocked, a first control position 20b for a first direction of movement of the bucket cylinder 10, in which the consumer line 22 is connected to the delivery line 17 and the consumer line 23 is connected to the container line 21, and a second control position 20c for a second direction of movement of the bucket cylinder 10, in which the consumer line 23 is connected to the delivery line 17 and the consumer line 23 is connected to the container line 21.

[0026] The control directional valve 20 is electronically controlled and is operatively connected to an electronic control device 25 for control. The electronic control device 25 is operatively connected on the input side to a control element 26, for example, a joystick designed as a transmitter, which is operated and actuated by an operator of the work machine and, upon actuation, transmits a control command to the electronic control device 25.

[0027] The electronic control device 25 also serves to control the control directional valve 20 and is connected on the output side to electrical actuating devices 27a, 27b of the control directional valve 20.

[0028] In the illustrated embodiment, the control directional valve 20 is designed as a pilot-operated control directional valve and is electro-hydraulically actuated. For this purpose, electrically actuated pilot valves 28a, 28b are provided as actuating devices 27a, 27b for actuating the control directional valve 20. The pilot valves 28a, 28b are designed, for example, as pressure reducing valves actuated by means of a proportional solenoid. The pilot valves 28a, 28b are connected on the input side to a control pressure source (not shown in detail) for supplying a control pressure. When electrically actuated and thus actuated, the pilot valves 28a, 28b generate an actuating pressure that acts on the control directional valve 20 in the direction of the control position 20b or 20c to actuate the consumer 10.

[0029] In the Fig.3 shows the structure of the electronic control of the control directional valve 20 with the shaking function according to the invention for the consumer 10.

[0030] The control element 26 has a first actuating direction X1, X2, with which the movements of the bucket cylinder 10 and thus the movements of the bucket 9 can be controlled in both directions of movement.

[0031] In the illustrated embodiment, the control element 26 has a second actuating direction Y1, Y2 arranged perpendicular to the first actuating direction X1, X2, with which the movements of a further consumer, for example the boom cylinder 6 and thus the movements of the boom 5 in both directions of movement, can be controlled.

[0032] The control element 26 is connected to the electronic control device 25 by means of a signal line 30 for transmitting a control command to the electronic control device 25.

[0033] When the control element 26 is actuated and deflected in the direction X1, X2, the electronic control device 25 generates an actuation signal 31 from the signal of the control element 26 present in the signal line 30 for controlling the electrical actuation devices 27a, 27b of the control directional valve 20. The actuation devices 27a, 27b of the control directional valve 20 are connected to the electronic control device 25 by means of signal lines 32.

[0034] The signal of the actuated control element 26 present in the signal line 30 can be influenced and modified by means of a filter device 33 and / or a damping device 34 of the electronic control device 25 in order to generate the actuation signal 31 for controlling the electrical actuation devices 27a, 27b of the control directional valve 20.

[0035] According to the invention, an additional control element 35 is provided, which is also connected to the electronic control device 25 and upon actuation of which a shaking function of the consumer 10 is generated.

[0036] In the illustrated embodiment, the additional control element 35 is arranged on the control element 26, for example on the upper side of the control element 26 designed as a joystick, and is designed as a rotary wheel 36 which can be actuated with the thumb of a hand actuating the control element 26.

[0037] Upon actuation of the additional control element 35, the electronic control device 25 generates an additional actuation signal 37, which can be used to achieve a shaking movement of the consumer 10. The additional actuation signal 37 is preferably designed as a square-wave signal.

[0038] The amplitude and / or frequency of the additional actuation signal 37 can be controlled and thus changed using the additional control element 35 designed as a rotary wheel.

[0039] According to the invention, when the control element 26 and the additional control element 35 are actuated simultaneously, the electronic control device 25 generates a control signal 40 in the signal line 32 which controls the control directional valve 20 and in which the additional actuation signal 37 is superimposed on the actuation signal 31.

[0040] The actuation signal 31, the additional actuation signal 37 and the control signal 40 each represent flow characteristics of a volume flow Q or characteristics of the valve opening A of the control directional valve 20 over time t.

[0041] With a superimposed and thus simultaneous actuation of the control element 26 in the direction X1 or X2 and the additional control element 35, the actuation signal 31 is generated from the actuation and deflection of the control element 26 to control the control directional valve 20, and the additional actuation signal 37 is generated from the actuation of the additional control element 35. The actuation signal 40 controlling the control directional valve 20 is generated by superimposing the additional actuation signal 37 on the actuation signal 31, so that the actuation signal 40 corresponds to the sum of the actuation signal 31, caused by the actuation and deflection of the control element 26, and the additional actuation signal 37, caused by the actuation of the additional control element 26.The control valve 20 controlling the consumer 10 thus receives, on average, the actuation signal 31 from the normal deflection and actuation of the control element 26, which, upon simultaneous actuation of the additional control element 35, is superimposed with the additional actuation signal 37 for the shaking movement of the consumer 10. The shaking movement and thus the shaking function of the consumer 10 generated by the additional actuation signal 37 thus forms an additional function that is superimposed on the normal movement and thus the normal function of the consumer 10 determined by the actuation signal 31.

[0042] The shaking function of the consumer 10 according to the invention has a number of advantages.

[0043] The shaking function according to the invention enables the operator of the work machine to harmoniously and intuitively execute the shaking function of a consumer 10. The shaking movement of a consumer 10 can be achieved with the invention without jerky and rapid movements of the control element 26. Rather, with the invention, the operator can perform a normal consumer movement of the consumer 10 by deflecting the control element 26, onto which the shaking movement of the consumer 10 is superimposed upon the simultaneous actuation of the additional control element 35. When the shaking function is active, the deflection of the control element 26 continues to specify the main movement of the consumer 10 through the mean value of the control signal 40 formed by the actuation signal 31. The shaking movement caused by the additional actuation signal 37 is superimposed on this main movement of the consumer 10 predetermined by the deflection of the control element 26.This ensures smooth and fluid operation of the consumer 10 and other consumers even during the shaking function. The additional control element 35 can be actuated in an ergonomically favorable manner. With the additional control element 35 designed as a rotary dial 36, the additional control element 35 can also control the amplitude and / or frequency of the additional actuation signal 37, thereby allowing the amplitude and / or frequency of the superimposed shaking movement of the consumer 10 to be controlled in an ergonomically favorable and simple manner in order to optimally match the amplitude and / or frequency of the superimposed shaking movement of the consumer 10 to the mechanical properties of the consumer, such as inertia, rigidity, and natural frequency.

[0044] The invention is not limited to the illustrated embodiment, in which the inventive shaking function is described on the bucket cylinder 10 and thus the bucket 9 of an excavator. It is understood that the inventive shaking function can also be applied to another consumer, for example, the dipper arm cylinder 8 and thus the dipper arm 7.

[0045] In addition, the invention is not limited to the design of the work machine as an excavator, but can be implemented in other work machines, for example a wheel loader for a shaking function of a bucket.

Claims

[1] Hydrostatic drive system with at least one hydraulic consumer (6; 8; 10) which is controlled by means of a control directional valve (20), wherein the control directional valve (20) is electronically controlled and is operatively connected to an electronic control device (25) for actuation, wherein the electronic control device (25) is connected to a control element (26) designed as a joystick and the electronic control device (25) generates an actuation signal (31) for actuating the control directional valve (20) upon actuation of the control element (26), wherein an additional control element (35) is provided which is connected to the electronic control device (25), and upon actuation of which additional control element a shaking function of the consumer (6; 8;10) can be generated, wherein the electronic control device (25) generates an additional actuation signal (37) upon actuation of the additional control element (35), wherein the electronic control device (25) generates a control signal (40) which controls the control directional valve (20) upon simultaneous actuation of the control element (26) and the additional control element (35), in which control signal the additional actuation signal (37) is superimposed on the actuation signal (31), wherein the additional control element (35) is arranged on the control element (26); characterized by that the amplitude and / or the frequency of the additional actuation signal (37) can be controlled with the additional control element (35), wherein the additional control element (35) is designed as a rotary wheel (36) which is arranged on the control element (26) designed as a joystick, wherein the additional control element (35) can be actuated with a thumb of a hand of an operator operating the control element (26). [2] Hydrostatic drive system according to claim 1, characterized by that the additional actuation signal (37) is designed as a square wave signal.

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