JP6899627B2 - Fluid circuits and machines with fluid circuits - Google Patents

Description

The present invention starts with a fluid circuit for controlling a fluid driven machine or for controlling a fluid consuming device. The present invention further relates to a machine having at least one fluid consuming device that can be controlled by a fluid circuit.

German Patent Application No. 102012009665, which will be published later, discloses a fluid circuit for controlling the press. The press is, for example, a deep drawing machine, punching machine or press device having an upper tool and a lower tool to apply pressing force to the work piece and for machining the work piece. The above fluid circuit has a discharge control unit and a valve control unit.

Further, prior art knows cylinder systems or actuators (double rods or differential cylinders) with extremely high dynamic characteristics for die cushioning or punching / nibbling applications, which control the position of at least one cylinder. And force control is performed. For this purpose, multiple servo valves with extremely high dynamic characteristics are used for control, and these servo valves are designed for large volumetric flow rates and large pressures, and are provided in multiple control plates. There is. These control plates, at their disadvantage, require extremely large space requirements and weigh as much as tons. The control plate can be placed directly on the cylinder to be controlled. Large plurality of accumulators are provided for pressure medium supply, and these accumulators are generally placed directly on the control block of the cylinder, which has a control plate. For filling the accumulator, a supply unit with a metering pump or pressure control pump equipped with a pressure switch and a filling valve can be provided. The supply unit is fluidly and spatially separated from the cylinder and control block. This supply unit is a motor / pump drive with a simple configuration, a large installation space, and a high output (for example, an output of 150 to 250 kW in a die cushion application). For this supply unit, a cooler / filter circulation path with a large installation space (eg with an output of 300-500 kW in a die-cushion application) is used and has a capacity of 6000-12000 liters (eg in a die-cushion application). ) Multiple tanks are used. In this case, the supply and control of one or more cylinders is performed by a plurality of servo valves. Therefore, these servo valves control a large volume flow rate (Qmax), as already described above, and these servo valves are designed for a large pressure difference (delta p-max). At the time of control, a large output loss is unfavorably generated, and this output loss raises the temperature of the pressure medium or the oil, and further deteriorates the oil rapidly.

German Patent Application No. 102012009665 German Patent Application No. 102013221410

An object of the present invention is to provide a fluid circuit, which makes it possible to easily control a fluid driven machine with extremely high dynamic characteristics and high accuracy in terms of device technology, and has the drawbacks mentioned above. To be resolved. A further object of the present invention is to provide a fluid driven machine having such a fluid circuit.

The above-mentioned problem with respect to a fluid circuit is solved by the characteristic configuration according to claim 1, and the above-mentioned problem with respect to a fluid driven machine is solved by the characteristic structure according to claim 15.

Other advantageous developments of the invention are set forth in another dependent claim.

In the present invention, a fluid circuit is provided for controlling a fluid driven machine, particularly a press, a die cushion shaft in a mechanical press, and a punching shaft in a nibbling machine. This circuit has a discharge control unit and a valve control unit that are fluidly arranged in parallel with each other. This discharge control unit has a displacer, especially a fluid machine (which can advantageously be used for four quadrant operation), which advantageously has two ports capable of supplying and discharging a pressure medium, respectively. Have. Each port of the fluid machine is connected to the fluid driven machine via one flow path, whereby a closed fluid circuit can be formed. On the other hand, the valve control unit can be connected to the machine in an open fluid circuit. As a result, this valve control unit operates as an open circuit.

With this solution, it is possible to control the fluid driven machine with high dynamic characteristics and energy optimum. When the machine has, for example, a cylinder, the discharge control unit can expand and contract the cylinder at high speed. In this case, the parallel valve control unit can perform active and accurate control of the cylinder via the open circuit (volume / pressure supply and discharge metering). Since the valve control unit is generally constructed to be much smaller than the discharge control unit, this valve control unit is technically simpler in terms of equipment and is closer in terms of fluid, for example, in a fluid driven machine. Since it can be arranged in the cylinder, the fluid flow path is shortened, and the fluid rigidity between the valve control unit and the fluid driven machine is increased, thereby increasing the controllability. Therefore, the "fluid spring" is shortened by the above-mentioned fluid control, so that the optimum control characteristics can be obtained.

Therefore, the circuit according to the present invention can drive a cylinder system having high dynamic characteristics such as die cushion application or punching / nibbling application, and can provide an extremely small valve control unit as compared with the prior art described at the beginning. It can be used, which significantly reduces output loss. The speed of the application is, for example, between 500 and 1500 mm / s, and / or the maximum speed of the application can be reached with the shortest displacement, eg 5-10 mm, and / or the application. The maximum speed of can be reached in the shortest time, eg 5-10 ms, and / or the maximum force of the application can be reached in the shortest time, eg 5-10 ms. At this time, this maximum force can be, for example, 20, 50, 100, 150 or 200 tons.

According to the circuit according to the present invention, as already cited above, a valve control unit having a relatively small installation space is provided in a cylinder system having high dynamic characteristics such as a die cushion application or a punching / nibbling application. Can be used. In the prior art, a plurality of valves with nominal dimensions of 25, 32, 50 or 63 are generally used for such applications. According to the present invention, these valves are replaced by the above-mentioned discharge control units, which are advantageously large, have low inertia, and have extremely high dynamic characteristics. As the fluid motor, for example, a Hagglunds motor that advantageously conveys 1, 2 or 5 liters / revolution can be used. Advantageously, the discharge control unit is designed so that the discharge control unit has a large stroke volume at a low rotation speed, for example, at about 500 rpm, about 2500 liters / minute can be obtained. Such a relatively low rotation speed, for example, about 500 revolutions / minute, can be reached more quickly than the conventionally common revolutions of about 3000 revolutions / minute.

The solution according to the invention further has the advantage of being able to replace the large accumulator or feed accumulator designed for high pressure with a capacity of 20 to 100 liters described at the outset. As an alternative, for example, small accumulators (high pressure accumulators) between about 2 liters and 4 liters can be used. A small accumulator is sufficient to actively supply the pressure medium to the valve control unit (with, for example, a control / servo valve of nominal size 6 or 10).

An accumulator (pre-pressure accumulator) having, for example, 4 to 10 liters can be provided to the discharge control unit in order to form a basic supply particularly on the low pressure side. In addition, a small pressure control pump or metering pump can be provided for the accumulator filling. This allows only two relatively small accumulators (one for discharge control and one for valve control) to be used, unlike in the prior art. In order to control this accumulator, unlike the conventional technology, only a small pump is required, and by extension, only a relatively low output electric motor for driving these pumps is required.

Further, the solution according to the present invention is advantageous in terms of maximum volume flow (Q _max ) and maximum pressure difference (delta p-max) because the valve control unit can be configured to be relatively small as compared with the prior art. Only much less energy is wasted. Thereby, for example, the cooling body / filter circulation path accompanied by the supply of water can be formed to be remarkably small.

Further advantageous in the solution according to the invention is that only a small tank is required.

In another embodiment of the present invention, while forming the fluid drive output of the discharge control unit, the pressure control curve and / or the displacement control curve and / or the speed control curve preset by the valve control unit at the same time. The deviation can be adjusted. As a result, the discharge control unit controls, for example, a fluid driven machine, so that a high adjustment speed is possible, and thus a large volume flow rate is possible. In this case, at the same time, the valve control unit having high dynamic characteristics can optimally fulfill the control problem, especially with short switching and control time.

The discharge control unit is advantageously designed so that it forms a major part of the drive output for the fluid driven machine.

The valve control unit is advantageously designed so that it cannot form the main part of the drive output for the fluid driven machine.

In another embodiment of the invention, the valve control unit supplies or discharges the pressure medium during the start and / or kinetic and / or braking phases of the machine and / or discharge control unit.

The fluid machinery described above is advantageously configured to have a relatively small inertia, which in turn has high dynamic properties and a relatively large stroke volume. Due to this large stroke volume, the fluid machine can advantageously be driven at a relatively low speed. In another embodiment of the invention, the fluid machine can be driven by an electric motor. This electric motor is advantageously configured to have a relatively small inertia, and thus a high dynamic characteristic, so that it can be used at a relatively low rotation speed. The combination of fluid machines with low inertia and large volume provides an emission control unit that can control the fluid driven machine at extremely high speed, high dynamic characteristics (clock number), and high speed. This allows, for example, the cylinder of the machine to be expanded and contracted with high dynamic characteristics and speed. It is also possible here to change the direction of rotation of the fluid machine at extremely high speeds. The electric motor is, for example, a torque motor or a servo motor having high dynamic characteristics. Such fluid machines combined with electric motors are known, for example, from a later published publication, German Patent Application No. 102013221410. As a result, the fluid driven machine can be controlled with high dynamic characteristics in combination with the valve control unit. An "intelligent" recoverable drive can be provided for the electric motor (HCS).

The electric motor is advantageously used for control, but is also used for controlling a fluid driven machine as needed. In this case the valve control can have a (control / servo) valve, which in addition can actively control the machine with extremely high dynamic characteristics, and this valve is the discharge control unit. The valve control is designed to adjust what cannot physically and technically act. The nominal size of the valve is, for example, 6 or 10.

"Active control" advantageously means supplying and discharging a pressure medium to and from the machine, actively up to maximum pressure.

The valve control unit preferably has a control valve. This control valve can be used in this case to control the open circuit. This control valve is advantageously designed so that it has high dynamic characteristics and high accuracy with respect to the amount of pressure medium to be controlled. As a result, a valve control unit is used to advantageously control the fluid driven machine with high accuracy. Moreover, the control valve can be easily placed in close proximity to the fluid driven machine in fluid form. This is because this control valve requires less installation space than the fluid machinery and electric motors, or compared to the valves mentioned at the beginning. For example, the control valve is a servo control valve.

This control valve is advantageously placed as close as possible to the fluid driven machine. Since the valve control unit has an extremely compact size and thus has a small control plate or a small control block, this valve control unit is more fluid and spatially fluid driven machine than the prior art. It can be placed closer together. This makes the "fluid spring" between the valve gear and the machine extremely short.

The control valve advantageously has two working ports, one pressure port and one tank port in another embodiment. The work port can be connected to a fluid driven machine, for example, to the work chamber of one cylinder. The first working port can be connected to the tank port at the first switch position, the second working port can be connected to the pressure port at the first switch position, and the second working port can be connected to the tank port at the second switch position via the valve slider of the control valve. Also, the first working port can be connected to the pressure port. The first working port can be connected to the tank port at the first switch position, the second working port can be connected to the pressure port at the first switch position, and the second working port can be connected to the tank port at the second switch position via the valve slider of the control valve. Also, the first working port can be connected to the pressure port. It is also conceivable that the control valve preferably has a third switch position provided between the first and second switch positions. At this third switch position, the valve sliders can, for example, throttle all ports and connect to each other, thereby adjusting the pressure of the fluid driven machine or cylinder as a safety measure. The valve slider of the control valve is advantageously continuously adjustable.

In another embodiment of the present invention, a shutoff valve configured as a switching valve is advantageously provided. According to this shutoff valve, the control valve can be decoupled from the fluid machine. Advantageously, the shutoff valve is fluidly arranged between the control valve and the machine.

The shutoff valve can have two input ports, each input port being connected to each working port of the control valve. In addition, the shutoff valve has two work ports that can be connected to the machine.

Advantageously, an accumulator is connected to the pressure port of the control valve. The accumulator can be designed to obtain the working pressure required for the fluid driven machine. The accumulator is advantageously a high pressure accumulator. The accumulator can be connected to the tank, for example, via a release valve and / or via a pressure limiting valve. Further, a pressure measuring device for a high pressure accumulator can be provided.

Alternatively or additionally to the accumulator, a fluid pump can be connected to the pressure port of the control valve. This fluid pump is advantageously a pressure / transport flow controlled fluid pump. Advantageously, a check valve is placed between the fluid pump and the pressure port of the control valve. This check valve opens toward the control valve in the pressure medium flow direction.

In another embodiment of the present invention, a prepressure device is provided, which preloads a fluid with a preset pressure in one or two of the above two channels. Can be applied or this pressure is applied. The prepressure device can be connected to one of the two flow paths via a check valve, or can be connected to each flow path via a check valve, respectively. This check valve opens toward the flow path in the pressure medium flow direction. The prepressure device advantageously has an accumulator connected to one or two channels. This connection is made via one or more check valves. The accumulator can be connected to the tank via a release valve and / or via a pressure control valve. Advantageously, a pressure measuring instrument is additionally provided. The accumulator is designed so that, in another embodiment of the invention, the required prepressure is obtained, which makes the accumulator advantageously a low pressure accumulator. Alternatively or additionally to the accumulator, a valve for preloading, especially a pressure reducing valve, may be provided. To apply prepressure, this pressure reduction valve is connected to a fluid pump, especially to a metering pump.

A cleaning device is provided to clean the fluid circuit, which is connected to at least one flow path and can be released via a pressure medium from at least one flow path. it can. The cleaning device can be configured to relatively reduce or avoid the effects of pressure control and / or displacement control and / or speed control of the machine. The drive control of this cleaning device, i.e., the cleaning process, is performed, for example, when the workpiece is being replaced during the operation of the machine or when the cylinder is "should be stationary" in position control, thereby the actual operation. The cleaning equipment is deactivated during the processing process to prevent negative impact on control. The cleaning device is connected to the flow path via an adjustable throttle. If the cleaning device is connected to two channels, the cleaning device is connected to each of the channels via an adjustable throttle. Further, the cleaning device has a cleaning valve, which can open and close the pressure medium port between one or two flow paths and the tank. The throttle is advantageously located between the two channels and the wash valve. The wash valve can be operated, for example, manually or electromagnetically or fluidly. It is also conceivable to use this cleaning valve as a safety valve for releasing pressure.

Advantageously, the discharge control unit and the valve control unit are double protected and monitored. One (or two) safety valves can be arranged in one or two of the above flow paths leading to the machine of the discharge control unit and the valve control unit. In the closed state of the safety valve, the corresponding flow path can be shut off, and in the open state of the safety valve, the corresponding flow path can be opened. When one safety valve is provided in each flow path, the hydric driven machine can be fluidly shut off by this safety valve in the shut-off flow path. One shutoff valve or each shutoff valve can be open and closed controlled via a limit switch valve. What is generally intended here is to double the safety valves (112, 114) back and forth in the two channels (68, 70), depending on the required performance level or safety category. It can and must be installed.

In this case, the safety valve combined with the shutoff valve and / or the third switch position of the control valve can provide double or triple protection against the valve control unit.

Similarly, double protection is provided by combining the safety valve with the electric protection circuit for the discharge control unit. This protection circuit can be provided in the drive unit of the fluid machine. This protection circuit provides, for example, a safer drive enablement of the drive unit of the fluid machine. Further, for example, this protection circuit can control a stop brake in an electric motor capable of driving a fluid machine.

A pressure medium can be supplied in the closing direction by a first pressure chamber (cylinder chamber) to the valve elements of each safety valve, which can advantageously be configured as a logic valve, and a second pressure chamber (ring chamber). ) Can supply the pressure medium in the open direction. Through each limiter switch valve, the first pressure chamber and the second pressure chamber of each logic valve can be alternately connected to the tank or the pressure medium source.

Further, a directional control valve having an output port and two input ports can be provided, and the directional control valve connects the input port having the highest pressure and the output port. A limit switch valve is connected to each of the output ports, whereby this output port can be connected to one of a plurality of pressure chambers of each logic valve. In this case, the preload system can be connected to the first input port of the directional control valve, and one of the two flow paths can be connected to the second input port.

The two channels are advantageously connectable to each other via at least one pressure limiting valve. This pressure limiting valve is, for example, a pre-controlled pressure limiting valve having a relief. This relief is advantageously provided by a relief valve. The pressure medium of the accumulator of the valve control unit can be applied to the valve element of the pressure limiting valve in the closing direction. In another embodiment of the invention, the two channels are connectable via two pressure limiting valves configured corresponding to the aspects described above. Here, one pressure limiting valve can be operated by the pressure medium in the first flow path, and another pressure limiting valve can be operated by the pressure medium in the second flow path.

Advantageously, another pressure limiting valve is provided, through which the pressure in one or two flow paths leading to the tank can be released. The pressure limiting valve can be configured corresponding to one or more corresponding aspects of the pressure limiting valve described above. The pressure limiting valve is connected to each flow path via a check valve, and each of the check valves closes toward the flow path when viewed in the pressure medium flow direction.

In the present invention, the fluid driven machine has a fluid cylinder controlled by a circuit according to one of the plurality of aspects described above. Here, it is possible to provide a second fluid cylinder controlled by a circuit according to one of the plurality of aspects described above.

The cylinder is, for example, a differential cylinder or a double rod cylinder, and the double rod cylinder does not need to advantageously adjust the volume of the pressure medium.

The machine is advantageously a mechanical press and the cylinder constitutes a die cushion shaft.

Alternatively, the machine is a nibbling machine.

A plurality of examples of the fluid circuit according to the present invention and the fluid driven machine according to the present invention are shown in the drawings. Here, the present invention will be described in detail based on the drawings of these drawings.

It is a circuit diagram of the fluid circuit according to 1st Embodiment of this invention. It is a circuit diagram of the fluid circuit according to 2nd Example. It is a circuit diagram which shows a part of the fluid circuit by 3rd Example. It is another circuit diagram which shows a part of the fluid circuit by 3rd Example. It is still another circuit diagram which shows a part of the fluid circuit by 3rd Embodiment. It is a graph which shows the stroke curve, velocity curve and force curve plotted with respect to time which shows the operation of a fluid circuit. It is another graph showing the stroke curve, the velocity curve and the force curve plotted with respect to time showing the operation of a fluid circuit. It is a circuit diagram of the fluid circuit of this invention by another Example.

According to FIG. 1, the fluid driven machine 1 has a first cylinder 2 and a second cylinder 4. The machine 1 is, for example, a mechanical press, and the cylinder 4 may form a die cushion shaft. The first cylinder 2 is controlled via the first fluid circuit 6, and the second cylinder 4 is controlled via substantially the same second fluid circuit 8. The fluid circuits 6 and 8 have discharge control units 10 to 12 and valve control units 14 to 16, respectively. The discharge control units 10 and 12 and the valve control units 14 and 16 of the circuits 6 and 8 are fluidly arranged in parallel with each other here.

Hereinafter, the configurations of the circuits 6 and 8 will be described in detail based on the circuit 6 of the cylinder 2. The discharge control unit 10 has a fluid machine 18 that can be used for four-quadrant operation. This fluid machine is designed so that it has a large stroke volume and a small inertia. Further, the fluid machine 18 has two ports A1 and A2. The fluid machine can be driven at a low rotation speed by a controlled electric motor 20. This electric motor is a torque motor having a small inertia. In addition, this electric motor is designed so that it can be used at low speeds. Due to its low inertia and low rotation speed, this torque motor has great dynamic characteristics. The combination of the electric motor 20 and the fluid machine 18 designed as described above provides discharge control capable of moving a large volumetric flow in extremely time, which makes the piston 22 of the cylinder 2 high. It can expand and contract at speed. In addition, the piston can change direction rapidly.

According to FIG. 1, one side of the piston 22 is connected to the piston rod 24. The piston 22 separates the first cylinder chamber 26 and the second cylinder chamber 28 in the cylinder 2. The first cylinder chamber 26 is connected to the port A1 of the fluid machine 18 via the flow path 30, and is connected to the port A2 of the fluid machine 18 via the second flow path 32. Therefore, the discharge control unit 10 constitutes a closed fluid circuit together with the cylinder 2.

A valve control unit 14 fluidly arranged in parallel with the discharge control unit 10 is also connected to the flow paths 30 and 32. The valve control unit 14 has a continuously adjustable control valve 34 (servo control valve). The control valve 34 is connected to the flow path 30 via the work port A, and is also connected to the flow path 32 via the work port B. Further, the control valve 34 is connected to the pressure medium source via the pressure port P and is connected to the tank via the tank port T. At basic position 0 (third switching position) centered by the spring, ports A, B, P and T are connected to each other by the valve slider of the control valve 34. Starting from the basic position 0, the valve slider of the control valve 34 can be slid in the direction of the first switch position a. Here, the pressure port P is connected to the work port B, and the work port A is connected to the tank port T. When the valve slider departs from the basic position 0 and slides in the direction of the second switch position b, the pressure port P is connected to the working port A and the working port B is connected to the tank port T. The control valve 34 is configured such that it has a very short switching and control time. Since the fluid machine 18 has a large stroke volume and therefore can utilize the main part of the drive output of the cylinder 2, the control valve 34 can be configured to be relatively small. Therefore, the control valve can be operated with extremely high dynamic characteristics, and the switching and control time is short. Since the required space of the control valve 34 is small, it can be flexibly arranged in the cylinder 2 in terms of device technology, so that it can be provided extremely close to the cylinder 2 in terms of fluid. As a result, fluid robustness is obtained, and the controllability of the cylinder 2 is improved. The control valve 34 can be operated, for example, by a fluid.

The piston 22 of the cylinder 2 can be, for example, an upper piston, and the piston 36 of the cylinder 4 can be a lower piston, which work together to machine the workpiece.

According to FIG. 2, the machine 38 has a cylinder 40 configured as a double rod cylinder or an upper piston double rod cylinder. Further, the machine has a cylinder 42, which is also configured as a double rod cylinder or a lower piston double rod cylinder. The cylinders 40 and 42 are controlled via valve control units, and these valve control units are arranged in control blocks 46 or 48, respectively. A discharge control unit 50 or 52 is provided fluidly in parallel with the valve control unit for each of the cylinders 40 and 42. The valve control unit and the discharge control unit 50 of the control block 46 are fed by the power electronics device 54. The same applies to the control block 48 and the emission control unit 52, which are powered by the power electronics device 56. A fluid supply unit 58 is provided for fluid supply of the valve control unit in the control blocks 46 and 48. A control cabinet 60 having a logic and control unit is provided to drive and control the valve control units of the control blocks 46 and 48 and the fluid supply unit 58. One mass body 62 or 64 can be moved through each of the cylinders 40 and 42.

FIG. 3a shows the fluid circuit 65 of the upper piston. The upper piston or cylinder 66 is configured as a double rod cylinder. The upper piston is connected to the port A1 of the fluid machine 18 via the first flow path 68, and is connected to the port A2 of the fluid machine 18 via the second flow path 70. Here, the fluid machine 18 is driven by the electric motor 20. A valve control unit having a control valve 34 is provided in parallel fluidly. An adjustable fluid pump 74 (see FIG. 3c) is connected to the pressure port P via a check valve that opens toward the control valve 34 in the pressure medium flow direction. An accumulator 76 is connected between the check valve 72 and the control valve 34, and this accumulator is a high-pressure accumulator. The accumulator is protected from the tank 80 (see FIG. 3c) via a pressure limiting valve 78. Further, the accumulator 76 is associated with a discharge valve 82 for discharging the pressure medium to the tank 80.

The work ports A and B of the control valve 34 are connected to the first or second flow paths 68 and 70 via a shutoff valve 84 configured as a switching valve. The shutoff valve 84 has a port X connected to the work port A of the control valve 34 and a port Y connected to the work port B of the control valve 34. The shutoff valve 84 is connected to the second flow path 70 via the work port A, and is connected to the first flow path 68 via the work port B. At the first switching position of the shutoff valve 84, ports A, B, X and Y are separated from each other. At the second switching position, the working port A is connected to the port X, and the working port B is connected to the port Y. Therefore, at this switching position, the control valve 34 is connected to the flow path 70 or 68 by the working ports A and B.

Further, the fluid circuit 65 has a fluid prepressure device 86. This prepressure device has a pressure reducing valve 88 including a pressure port P, a tank port T, and a working port A. A metering pump 90 (see FIG. 3c) is connected to the pressure port P. The tank port T is connected to the tank 80 of FIG. 3c. A check valve 92 that opens toward the pressure reduction valve 88 is arranged between the pressure port and the metering pump 90. The pressure reduction valve 88 can be connected to the first and second flow paths 68 and 70 via the work port A. Here, the first flow path 68 can be connected to the work port A via the check valve 94, and the second flow path 70 can be connected to the work port A via the check valve 96. The check valves 94 and 96 open in the pressure medium flow direction away from the pressure reduction valve 88, respectively. As a result, a prepressure is applied to the fluid circuit 65 having the cylinder 66 by the low pressure via the metering pump 90 and the pressure reduction valve 88. Additionally, the working port A is connected to an accumulator 98 in the form of a low pressure accumulator. The low pressure accumulator can be connected to the tank 80 of FIG. 3c via the pressure limiting valve 100 and the release valve 102.

According to FIG. 3a, the fluid circuit 65 additionally has a cleaning device 104. This cleaning device has a cleaning valve 106, and two flow paths 68 and 70 can be connected to the tank 80 of FIG. 3c via the cleaning valve. The cleaning valve 106 configured as a switching valve has two working ports A and B, and these ports are connected to each of the flow paths 70 or 68. Further, the cleaning device 104 has two tank ports T connected to the tank 80. At the spring preloaded first switching position of the valve slider of the wash valve 106, all ports are disconnected from each other. In a second switching position that can be operated manually or electromagnetically, the valve slider connects the work port A to the first tank port T and the work port B to the second tank port T. The working port A is further connected to the flow path 70 via an adjustable throttle 108. The same applies to work port B, which is connected to the first flow path 68 via an adjustable throttle 110.

A first safety valve 112 or a second safety valve 114 is provided to protect the fluid circuit 65 or the cylinder 66. These are logical valves, respectively. The safety valve 112 can control the opening and closing of the first flow path 68. The safety valve 114 can control the opening and closing of the second flow path 70. With the flow paths 68 and 70 closed and controlled, the control valve 34, the fluid machine 18, the prepressure device 86 and the cleaning device 104 are separated from the cylinder 66. Since the configurations of the safety valves 112 and 114 are the same, only the safety valve 112 on the upper side of FIG. 3a will be described in detail below for the sake of clarity. The safety valve 112 configured as a logic valve is configured as usual. The valve body 116 limits the cylinder chamber 118, and a pressure medium can be applied to the valve body in the closing direction by the spring force of a spring through the cylinder chamber and through the limit switch valve 120. .. Further, the valve body 116 limits the ring chamber 122, and the valve body is subjected to a pressure medium via the limit switch valve 120 in the opening direction through the ring chamber and against the spring force of the spring. Can be added. The limit switch valve 120 has two working ports A and B, a tank port T, and a pressure port P. The work port A is connected to the cylinder chamber 118, and the work port B is connected to the ring chamber 122. The tank port T is connected to the tank 80 of FIG. 3c. The limit switch valve 120 is connected to the output port AW of the shuttle valve 124 via the pressure port P. The shuttle valve 124 further has a first input port E1 and a second input port E2. The input port E2 is fluidly connected to the prepressure device 86 and the accumulator 98, and this connection is made by fluidly connecting the input port E2 between the check valves 94 and 96. It is said. Alternatively, it is conceivable to connect the input port E2 and the accumulator 76. On the other hand, the other input port E1 is connected to the second flow path 70. As a result, the input port E1 is advantageously connected to one of the flow paths on which the load pressure or weight pressure of the machine to be operated is acting. In this case, the port E1 or E2 having the higher pressure is connected to the output port AW and is connected to the pressure port P of the limit switch valve 120. The limit switch valve 120 has a valve slider, which is preloaded by a spring at the first switch position a via a valve spring. Here, the ring chamber 122 of the safety valve 112 is connected to the tank 80, and the cylinder chamber 118 is connected to the pressure medium source, i.e. to the flow path 70 or the prepressure device 86. Therefore, the safety valve 112 is closed at the first switch position a. The valve slider of the limit switch valve 120 can be manually or electromagnetically slid to the second switch position b. At the second switch position b, the cylinder chamber 118 is connected to the tank and the ring chamber 122 is connected to the pressure medium source. That is, it is connected to the flow path 70 or the prepressure device 86, and the safety valve 120 is opened accordingly.

According to FIG. 3a, the flow paths 68 and 70 are connected to each other via the first pressure limiting valve 124 and the second pressure limiting valve 126. The first pressure limiting valve 124 can be operated by the pressure medium in the flow path 70, or the second pressure limiting valve 126 can be operated by the pressure medium in the flow path 68. The pressure limiting valves 124 and 126 are pressure limiting valves that have a relief portion in the form of a directional control valve 128 and are pilot-controlled. The pressure medium from the accumulator 76 can be applied to the valve body of each of the pressure limiting valves 124 and 126, or the pressure medium from the fluid pump 74 can be applied in the closing direction (the pressure medium from the fluid pump 74 can be applied in the closed direction). See Figure 3c). The pressure medium can be released to the tank via each directional control valve 128. Another pilot-controlled pressure limiting valve 132 having a relief portion is connected to the first flow path 68 or the second flow path 70 via the first check valve 134 and the second check valve 136. The check valves 134 and 136 open toward the pressure limiting valve 132 in the pressure medium flow direction, respectively. This pressure control valve can open the pressure medium connection to the tank 80. The pressure limiting valve can also be supplied with a pressure medium from the accumulator 76 or fluid pump 74 via the control line 130 in the closed direction (see FIG. 3c) and the directional control valve 128. It is also possible to escape through.

The double rod cylinder 66 of FIG. 3a has a displacement measuring system 138. Further, a pressure measuring device 140 is connected to each cylinder chamber of the cylinder 66.

FIG. 3b shows the lower piston or cylinder 142. This cylinder is controlled by the fluid circuit corresponding to the fluid circuit 65, corresponding to the cylinder 66 in FIG. 3a. The cylinders 66 and 142 work together and can be part of a mechanical press with a die cushion shaft.

FIG. 3c shows a unit 144 for supplying a pressure medium to the fluid circuits of cylinders 66 and 142 shown in FIGS. 3a and 3b. The output side of the fluid pump 74, which can be adjusted via the pressure transfer flow controller, is connected to the pressure port P of the control valve 34 via the pump line 146 and the check valve 72 of FIG. 3a. The fluid pump 74 can be driven by an electric motor 148. Further, the electric motor 148 is connected to the metering pump 90, and the metering pump is connected to the pressure reducing valve 88 via the pump line 150 and the check valve 92 of FIG. 3a. Both the pump line 146 and the pump line 150 can release pressure to the tank 80 via the pressure limiting valve 152. Further, the two tank lines 154 and 156 and the leak line 158 are connected via the circuit 65 of the cylinders 66 and 142 of FIGS. 3a and 3b. The tank pipeline 154 is provided with a cooling and filtering device 160. The tank line 154 is advantageously connected to the cleaning device 104.

In the following, FIGS. 4 and 5 illustrate a plurality of applications including the fluid circuit according to the present invention. As described above, the fluid circuit is advantageously envisioned to be used in punching nibbling machines or die cushioning systems with forces of 20, 30, 45, 67, 100, 150, 225 tonnes, etc. .. Here, for example, one model can be handled. This fluid circuit is, of course, used for another fluid cylinder shaft that has traditionally been driven / operated by extremely large valves and large accumulator stands, and has lost / wasted a lot of energy and is not optimally utilized. It is also possible to do.

According to the upper diagram of FIG. 4, one stroke s is shown for time t. The lower characteristic curve 162 shows the progress of the upper piston, and the upper characteristic curve 164 shows the progress of the lower piston. The stroke s of the upper piston has a substantially sinusoidal course. The process h of this process is about 100 mm. In this case, the lift is, for example, about 20 tons. The diameter of the piston can be about 160 mm and the diameter of the cylinder rod can be about 110 mm. The time interval z shown in this diagram is, for example, about 1.5 seconds. The stroke k of the lower piston shown in the characteristic curve 164 is about 100 mm, which is a pull stroke. The diameter of the lower piston is about 125 mm and the diameter of its piston rod is about 90 mm.

The central diagram of FIG. 4 shows the passage of velocity v with respect to time t. The lower characteristic curve 166 shows the course of the upper piston, and the upper characteristic curve 168 shows the course of the lower piston. The time interval z is again 1.5 seconds. The maximum moving speed of the upper piston is, for example, about 600 mm / s (10 tons of the lower piston). The discharge control unit for the upper piston can be driven at, for example, about 400 to 450 revolutions / minute and can convey 100 liters / minute. The maximum speed of the lower piston can also be about 600 mm / s. For example, about 220 liters / minute is conveyed by the discharge control unit of the lower piston and driven at about 200 to 250 revolutions / minute.

The force F is plotted for time in the lower diagram of FIG. The lower characteristic curve 170 shows the course of the upper piston, and the upper characteristic curve 172 shows the course of the lower piston. The time interval z is 1.5 seconds. The pulling stroke 174 is performed by a pressure difference of about 200 bars between the ports of each discharge control unit in both the lower piston and the upper piston. In this case, the upper piston has a force of about 20 tons and the lower piston has a force of about 10 tons. The curved portion 176 of the lower piston shows the discharge performed with a pressure difference of about 1 ton and about 25 bars. The duration here is about 200-300 ms. The elapsed portion 178 of the upper piston in the characteristic curve 170 represents the own weight of the piston.

The diagram of FIG. 4 shows a "draw cushion application" test. Here, about 20 strokes / minute are formed with a moving speed of about 600 mm / s and ^{a transport volume of about 15.000 cm 3.}

FIG. 5 shows a "punch application" test. Here, an upper piston capable of exerting a force of about 20 tons is provided. This test is performed at a moving speed of about 900 strokes / minute and 600 mm / s and a transport volume of up to ^{100 cm 3.} The upper diagram of FIG. 5 shows the passage of the stroke s with respect to the time t. The characteristic curve 180 shows twice the stroke time 182, which is about 30 ms for 4 mm, about 35 ms for 6 mm, and about 50 ms for 10 mm. The cycle time 184 can be about 60 ms, about 70 ms or about 110 ms in this case.

According to the central diagram of FIG. 5 where the velocity v is plotted for time t, the maximum velocity 186 can be about 450 mm / s, about 600 mm / s or about 650 mm / s. Here, the cylinder may have a piston with a diameter of about 160 mm and a piston rod with a diameter of about 110 mm. The volume flow can be about 290 liters / minute, about 380 liters / minute or about 420 liters / minute, and the number of revolutions can be about 300 revolutions / minute, about 400 revolutions / minute or 450 revolutions / minute.

In the lower diagram of FIG. 5, the force F is plotted for time t. The maximum force can be 20 tonnes and can occur at time intervals 188 of about 5-10 ms. The time interval 190 can be about 60 ms, about 70 ms or about 100 ms. The pressure difference in the discharge control unit can be about 200 bar.

FIG. 6 shows an alternative embodiment of the arrangement of safety valves. The remaining fluid arrangement configuration is not shown in FIG. 6 for clarity. In FIG. 6, the double rod cylinder 66 is shown along with the portions of the flow paths 68 and 70. Corresponding to FIG. 3a, pressure limiting valves 124 and 126 are arranged between these flow paths.

Unlike the embodiment in FIG. 3a, two safety valves 191 and 192 are arranged in the flow path 70. Further, the flow path 68 is also provided with two safety valves 194 and 196. The safety valves 191, 192 or 194, 196 of each of the flow paths 70 to 68 are fluidly arranged in series. That is, the flow path 68 is opened only when the two safety valves 194 and 196 are opened. When these safety valves 194 and 196 are closed, the flow path 68 is also shut off. The same applies to the flow path 70, which only opens when the two safety valves 191 and 192 are open. When one of the safety valves 191 and 192 is closed, the flow path 70 is also shut off. The safety valves 191 to 196 are configured to correspond to the safety valves 112 and 114 of FIG. 3a and can be fluidly connected accordingly. By arranging two safety valves 191, 192 or 194, 196 in each flow path 70 or 68, the safety of the fluid circuit 65 is further improved.

What is disclosed here is a fluid circuit in which the discharge control unit and the valve control unit are connected in parallel. The emission control unit is connected to one consumer device by two ports as in the case of a closed circuit. The parallel valve control unit is driven as an open circuit. Here, the discharge control unit provides the main part of the fluid drive output, and thus the fluid volume, while the valve control unit simultaneously adjusts the preset pressure, displacement control curve or velocity control curve. To.

1 Machine, 2,4 Cylinder, 6,8 Fluid Circuit, 10,12 Discharge Control Unit, 14,16 Valve Control Unit, 18 Fluid Machinery, 20 Electric Motor, 22 Piston, 24 Piston Rod, 26,28 Cylinder Chamber, 30 , 32 flow path, 34 control valve, 36 piston, 38 machine, 40, 42 cylinder, 44 frame, 46, 48 control block, 50, 52 discharge control unit, 54, 56 power electronics device, 58 supply unit, 60 control cabinet , 62,64 mass body, 65 fluid circuit, 66 double rod cylinder, 68,70 flow path, 72 check valve, 74 fluid pump, 76 accumulator, 78 pressure limiting valve, 80 tank, 82 release valve, 84 shutoff valve, 86 Preload device, 88 Pressure reduction valve, 90 Metering pump, 92, 94, 96 Check valve, 98 Accumulator, 100 Pressure limiting valve, 102 Release valve, 104 Cleaning device, 106 Cleaning valve, 108, 110 Throttle, 112, 114 Safety valve, 116 valve body, 118 cylinder chamber, 120 limit switch valve, 122 ring chamber, 124, 126 pressure limiting valve, 128 direction control valve, 130 control pipeline, 132 pressure limiting valve, 134, 136 check valve, 138 Displacement measurement system, 140 pressure measuring instrument, 142 cylinders, 144 units, 146 pump line, 148 electric motor, 150 pump line, 152 pressure check valve, 154, 156 tank line, 158 leak line, 160 cooling and filter Equipment, 162,164,166,168,170,172 characteristic curves, 174 draw strokes, 176,178 parts, 180 characteristic curves, 182 times the stroke time, 184 cycle times, 186 maximum speeds, 188,190 hour intervals, 191, 192, 194, 196 safety valves, A1, A2, X, Y ports, A, B work port, P pressure port, T tank port, 0 basic position, a 1st switch position, b 2nd switch position, AW output port, E1, E2 input port

Claims (12)

In a fluid circuit for controlling a fluid driven machine (2, 4) in which the discharge control unit (10) and the valve control unit (14) are fluidly connected in parallel.
The discharge control unit (10) has a fluid machine (18) provided with two ports (A1, A2).
Since the two ports (A1 and A2) form a closed fluid circuit, they can be connected to the machine (2) via the flow paths (30 and 32), respectively.
The valve control unit (14) can be connected to the machine (2) in an open fluid circuit.
When forming the fluid drive output of the discharge control unit (10), the deviation of the pressure control curve and / or the displacement control curve and / or the speed control curve preset by the valve control unit (14) at the same time. adjustable der the is,
One safety valve (112, 114) or a plurality of each in one or two flow paths (68, 70) leading to the machine (2) of the discharge control unit (10) and / or the valve control unit (14). Safety valve is placed,
In the closed state of the one safety valve (112, 114) or the plurality of safety valves, the corresponding flow paths (68, 70) are shut off, and the open state of the one safety valve (112, 114) or the plurality of safety valves. in the flow path corresponding the Ru opened,
A fluid circuit characterized by that. The valve control unit (14) supplies or discharges the pressure medium during the start phase and / or the motion phase and / or the braking phase of the machine (2, 4) and / or the discharge control unit (10).
The circuit according to claim 1. The fluid machine (18) is driven by an electric motor (20).
The circuit according to claim 1 or 2. The valve control unit (14) has a control valve (34).
The circuit according to any one of claims 1 to 3. A shutoff valve (84) is provided so that the control valve (34) can be separated from the flow path (68, 70).
The circuit according to claim 4. The control valve (34) is connected to an accumulator (76) designed to supply the required working pressure for the machine (2).
The circuit according to claim 4 or 5. A fluid pump (74) is connected to the control valve (34).
The circuit according to any one of claims 4 to 6. A prepressure device (86) for applying a preset fluid pressure to one or two flow paths (68, 70) is provided.
The circuit according to any one of claims 1 to 7. A cleaning device (104) that is connected to at least one flow path (68, 70) and can be released via a pressure medium from the at least one flow path (68, 70) is provided.
The cleaning device (104) is drive-controlled so that the influence of the pressure control and / or displacement control and / or speed control of the machine (2) is reduced or avoided.
The circuit according to any one of claims 1 to 8. The discharge control unit (10) and the valve control unit (14) are doubly protected and monitored.
The circuit according to any one of claims 1 to 9. The emission control unit (10) is protected by an electrical protection circuit.
The circuit according to any one of claims 1 to 10. A fluid driven machine comprising the circuit (1) according to any one of claims 1 to 11 and a fluid cylinder (2) controlled by the circuit (1).

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