Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
  • F04B49/00—Control, e.g. of pump delivery, or pump pressure of, or safety measures for, machines, pumps, or pumping installations, not otherwise provided for, or of interest apart from, groups F04B1/00 - F04B47/00
  • F04B49/002—Hydraulic systems to change the pump delivery
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
  • F04B1/00—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders
  • F04B1/12—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders having cylinder axes coaxial with, or parallel or inclined to, main shaft axis
  • F04B1/26—Control
  • F04B1/28—Control of machines or pumps with stationary cylinders
  • F04B1/29—Control of machines or pumps with stationary cylinders by varying the relative positions of a swash plate and a cylinder block
  • F04B1/295—Control of machines or pumps with stationary cylinders by varying the relative positions of a swash plate and a cylinder block by changing the inclination of the swash plate
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
  • F04B1/00—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders
  • F04B1/12—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders having cylinder axes coaxial with, or parallel or inclined to, main shaft axis
  • F04B1/26—Control
  • F04B1/30—Control of machines or pumps with rotary cylinder blocks
  • F04B1/32—Control of machines or pumps with rotary cylinder blocks by varying the relative positions of a swash plate and a cylinder block
  • F04B1/324—Control of machines or pumps with rotary cylinder blocks by varying the relative positions of a swash plate and a cylinder block by changing the inclination of the swash plate

Definitions

• the present invention relates to a device for controlling a hydraulic pump or a hydraulic motor.
• Hydraulic pumps are used in many technical applications in order to convey hydraulic fluid, in particular hydraulic oil, from a hydraulic fluid reservoir to a consumer.
• the consumer can be a hydraulic cylinder, for example, in which a pressure builds up as a result of the conveyance of the hydraulic fluid and a resistance counteracted by the hydraulic system in question and/or a consumer arranged therein, which pressure can be converted into a movement or a force.
• a component can be, for example, the arm of an excavator.
• the corresponding loading operating lever of the excavator is actuated by the excavator operator, as a result of which a certain target value, for example the volume flow in the hydraulic cylinder, is specified.
• the operating lever therefore acts as an actuator with which the delivery volume of the hydraulic pump is changed.
• Controllers known from the prior art for controlling a hydraulic pump change the delivery volume in many cases by means of an actuating cylinder and appropriately constructed combinations of orifices, springs, throttles and valves, which in turn are pilot-controlled passively via pressure feedback from the hydraulic system in question.
• Such regulators are known for example from DE 24 13 295 A1.
• changing the delivery volume is also referred to as changing the swivel angle.
• controllers known from the prior art have a specific combination of orifices, springs, throttles and valves, these controllers form a specific control task with specific control characteristics that can only be changed to a limited extent during operation of the consumer. If the control characteristics are to be changed, a spring or a set of springs, for example, must be manually pretensioned or replaced with a spring with a different spring characteristic. The same applies to the other hydraulic components of the regulator or hydraulic system in question.
• Controllers with an electrical, proportional control axis are also known from the prior art and in some cases are somewhat more flexible than the controllers described above, but the flexibility of the controllers named from the prior art leaves a lot to be desired.
• the valves used are in many cases designed as slide or piston valves, which inherently have a certain amount of leakage. This leakage leads to a loss of pressure within the relevant hydraulic system and a consequent reduction in the efficiency of the operation of the hydraulic system.
• the object of an embodiment or refinement of the present invention is to propose a device for controlling a hydraulic pump or a hydraulic motor, with which it is possible with simple and identically constructed components it is possible to flexibly solve different control tasks without significant adjustments to the hydraulic components.
• the leakage in the device should be largely reduced and thus the dynamics and efficiency of the regulation should be increased.
• An embodiment of the invention relates to a device for controlling a hydraulic pump, comprising
• a hydraulic pump with an input and an output, where o the input is connected to the hydraulic fluid reservoir by means of a first low-pressure line, o the output is connected to a high-pressure line to which a consumer can be connected,
• an adjusting unit which interacts with the hydraulic pump and with which the delivery volume of the hydraulic pump can be changed, the adjusting unit being arranged in a high-pressure secondary line connected to the high-pressure line,
• a control device which interacts with the sensor and the actuator in such a way that the high-pressure Seat valve can be activated taking into account the actual value detected by the sensor and the setpoint value specified by the actuator.
• Algorithms can be stored in the control device, with which different control tasks and control characteristics can be mapped.
• the control device can, for example, be designed in such a way that classic controllers, for example PI controllers or PID controllers with and without fixed value control, can be simulated.
• classic controllers for example PI controllers or PID controllers with and without fixed value control
• the control device has to be set up accordingly.
• the desired control characteristics can be selected in a suitable manner. It is not necessary to change the hydraulic components. As a result, the present device for controlling the hydraulic pump has a maximum of flexibility.
• the delivery volume of the hydraulic pump is changed with a corresponding activation of the high-pressure seat valve and consequently in a hydraulic way.
• the drive speed can vary due to the load, which means that the functionality of the hydraulic system is not adversely affected.
• comparatively simple drive motors can be used, which can be operated without speed control.
• internal combustion engines can be used that are constantly in their optimal speed range and can therefore be operated economically.
• Elaborate drive motors such as servo motors whose speed can be regulated are not necessary.
• digital depending on the requirements of the application, a variable speed motor can also be used to add another controlled variable to exploit the control properties.
• the hydraulic pump can have any number of pistons.
• the proposed device acts equally on all pistons. There is no individual regulation of individual pistons, as a result of which the proposed device can be kept simple in terms of construction and regulation.
• the adjustment unit comprises an actuating cylinder or is designed as an actuating cylinder, wherein
• a piston is slidably mounted in the actuating cylinder
• the piston divides the actuating cylinder into a first pressure chamber and a second pressure chamber
• the first pressure chamber is connected to the high-pressure line by means of a high-pressure secondary line and a working line,
• the second pressure chamber is connected to the hydraulic fluid reservoir by means of a second low-pressure line, and
• the piston is biased against the first pressure chamber with a return spring and/or a counter-piston.
• the high-pressure seat valve connects the high-pressure secondary line and the working line, with the working line being arranged downstream of the high-pressure seat valve.
• the pressure level in the working line can be influenced.
• the use of an actuating cylinder as an adjustment unit can be implemented technically in a comparatively simple manner and has proven to be reliable.
• a secondary low-pressure line can branch off from the high-pressure secondary line and open into the second low-pressure line, and a fixed or variable low-pressure throttle can be arranged in the secondary low-pressure line.
• a fixed or variable low-pressure throttle can be arranged in the secondary low-pressure line.
• the throttle can be fixed or variable.
• a variable throttle should be understood to mean that the narrowing of the cross section can be changed, in contrast to a fixed throttle.
• a variable throttle can, for example, specify two or more cross-sectional constrictions that differ from one another, which can be selected by a user, for example, by turning a handwheel. However, the selection can also be effected with the support of a servomotor or electromagnet, which is actuated accordingly by the user. However, this electrical actuation can also be activated by the control device and consequently integrated into the control system.
• the aim is to run the leakage as little as possible, which can be achieved with an increased manufacturing accuracy of the piston and the Stellzylin OFFENDERS.
• a residual leakage will always remain.
• the lower the leakage the slower the pressure in the first pressure chamber can decrease, which has a negative effect on the dynamics of the control.
• the low-pressure throttle arranged in the secondary low-pressure line a further path is created in addition to the leakage between the first pressure chamber and the second pressure chamber, with which the pressure in the first pressure chamber can be reduced. This increases the dynamics of the control.
• a secondary low-pressure line can branch off from the high-pressure secondary line and open into the second low-pressure line, and a low-pressure seat valve can be arranged in the secondary low-pressure line, which by means of the control device, taking into account of the actual value detected by the sensor and the setpoint value specified by the actuator can be activated.
• a low-pressure seat valve is used instead of a low-pressure throttle. While a choke cannot or can hardly be integrated into a control circuit because it is a passive element, the low pressure seat valve can be easily integrated into the control circuit. In this respect, the pressure reduction using the secondary low-pressure line can be selected very precisely. Both the dynamics and the precision of the control can be significantly increased here compared to the low-pressure throttle.
• the high-pressure seat valve can be designed as a seat valve with an integrated pressure limitation.
• a pressure limiting function is integrated into the high-pressure poppet valve. If the pressure in the hydraulic system, and in particular in the consumer, rises above a certain value, the high-pressure seat valve opens independently of an actuation that is initiated by the control device. As a result, it is ensured that the hydraulic pump swivels back and the pressure in the hydraulic system cannot exceed a specific value, regardless of the functionality of the control device. This protects the components of the hydraulic system.
• the high-pressure secondary line can have a bypass line, with which the high-pressure seat valve is bypassed.
• a pressure relief valve can be arranged in the bypass line.
• the pressure-limiting valve can be implemented, for example, as a spring-loaded check valve.
• a pressure-limiting function is implemented, which can be provided here as an alternative to the seat valve with an integrated pressure-limiting function or in addition.
• the term "pressure relief valve" is used in deviation from the usual definition, according to which a pressure relief valve is connected directly to the hydraulic reservoir. Apart from the arrangement of the proposed pressure relief valve, however, there is no difference in the function of a pressure-limiting valve according to the definition Alternatively, one can also speak of a pressure-dependent switching valve in this context.
• One embodiment of the invention relates to a device for controlling a hydraulic pump, comprising
• a hydraulic pump with an input and an output, where o the input is connected to a first low-pressure line with the hydraulic fluid reservoir, o the output is connected to a high-pressure line to which a consumer can be connected,
• an adjustment unit which interacts with the hydraulic pump and with which the delivery volume of the hydraulic pump can be changed, the adjustment unit being arranged in a high-pressure secondary line connected to the high-pressure line,
• a control device which interacts with the sensor and the actuator in such a way that the low-pressure seat valve can be activated taking into account the actual value detected by the sensor and the setpoint value specified by the actuator.
• the device does not include a high-pressure seat valve, but a low-pressure seat valve.
• the pressure level that is also present at the consumer is therefore always set in the first pressure chamber.
• the delivery volume of the hydraulic pump is mainly influenced by the activation of the low-pressure seat valve.
• the adjustment unit comprises an actuating cylinder or is designed as an actuating cylinder, wherein
• a piston is slidably mounted in the actuating cylinder
• the piston divides the actuating cylinder into a first pressure chamber and a second pressure chamber
• the first pressure chamber is connected to the high-pressure line by means of a high-pressure secondary line and a working line,
• the second pressure chamber is connected to the hydraulic fluid reservoir by means of a second low-pressure line, and
• the piston is biased against the first pressure chamber with a return spring and/or a counter-piston.
• an actuating cylinder as an adjustment unit can be implemented technically in a comparatively simple manner and has proven to be reliable.
• a fixed or variable high-pressure throttle is arranged in the high-pressure secondary line.
• the pressure in the first pressure chamber is not automatically the same as that at the consumer, but the reduced pressure level depends on the system status.
• the pressure load on the actuating cylinder is correspondingly lower.
• An embodiment of the invention relates to a device for controlling a hydraulic motor, comprising
• a hydraulic motor with an input and an output, wherein o the input is connected to the hydraulic fluid pressure reservoir by means of a high-pressure line, o the output is connected to a hydraulic fluid reservoir by means of a return line,
• a control device which interacts with the sensor and the actuator in such a way that the high-pressure seat valve takes into account the detected by the sensor th actual value and the setpoint value specified by the actuator can be activated.
• the displacement of the hydraulic motor is analogous to the displacement of the hydraulic pump. With the displacement, the performance or the torque, which is delivered by the hydraulic motor, can be influenced.
• An implementation of the invention relates to a device for regulating a hydraulic motor, comprising
• a hydraulic motor with an input and an output, wherein o the input is connected to the hydraulic fluid pressure reservoir by means of a high-pressure line, o the output is connected to a hydraulic fluid reservoir by means of a return line,
• an adjustment unit which interacts with the hydraulic motor and with which the displacement volume to be taken up by the hydraulic motor can be changed, the adjustment unit being arranged in a high-pressure secondary line connected to the high-pressure line,
• a control device which interacts with the sensor and the actuator in such a way that the low-pressure Seat valve can be activated taking into account the actual value detected by the sensor and the setpoint value specified by the actuator.
• the high-pressure seat valve as a high-pressure digital seat valve and/or
• the low-pressure seat valve as a low-pressure digital seat valve and/or
• the high-pressure seat valve with integrated Druckbegren tion function designed as a high-pressure digital seat valve with integrated pressure relief function.
• digital seat valves have the following properties: In the closed state, they are completely or almost completely leak-free, so that in the closed state they have no or almost no leakage in the present device cause and have larger opening cross-sections in the open switching state compared to conventional standard controllers. As a result, the dynamics and the efficiency of the control can be improved. The improved dynamics leads to a better response behavior of the relevant actuator and increased ease of use.
• Digital poppet valves not only assume two switching states (open and closed), but can also be used for dosing with appropriate activation by the electronics of the control unit. In addition, they have very short switching times of 5 msec and less.
• the volume flow of the hydraulic fluid, which flows through the relevant digital poppet valve can be set very precisely with the frequency of opening and closing who the. In addition to the pulse width modulation mentioned, there are also other control variants such as frequency modulation or combinations thereof.
• digital seat valves can be actuated with a control device, which can include power electronics.
• the control device is able to take into account a large number of parameters when actuating the digital seat valves in order to adjust the actual value of the parameter, for example the volume flow of the hydraulic fluid, as precisely as possible to the setpoint value specified by the actuator.
• the actual value can be recorded with the sensor.
• the actuator can be designed, for example, as an operating lever of an excavator. The control is significantly improved in comparison to controllers known from the prior art.
• a leak-free actuating cylinder can be used.
• an at least almost leak-free actuating cylinder can be provided by arranging appropriate seals on the piston, which seal the piston against the actuating cylinder.
• the pressure loss associated with the leakage during operation of the present device could then be significantly reduced or eliminated entirely, resulting in an increase in efficiency.
• a seal generates increased friction in the actuating cylinder, which means that the frictional forces of the seal have to be overcome in order to move the piston. This can lead to a delayed response.
• the digital seat valves can be actuated by the control device with a so-called "boost-and-hold" strategy.
• the clocked control causes pulse-like pressure increases in the first pressure chamber and in the second pressure chamber, which enables precise adjustment of the Piston despite occurring static / sliding friction (stick-slip effect) allows.
• a pressure present in the working line can be detected by means of a pressure sensor, with the pressure sensor interacting with the control device in such a way that the high-pressure seat valve and/or the low-pressure seat valve can be activated taking into account the pressure detected by the pressure sensor is.
• the pressure in the work line can be included as an additional parameter in the control of the system.
• the pressure recorded in the working line corresponds to the pressure that is present at the adjustment unit.
• the adjustment unit can be influenced more directly by the control device.
• the adjustment unit usually sets the delivery volume of the hydraulic pump or the displacement volume of the hydraulic motor.
• any delivery volume or the Hydraulic motor any absorption volume imprinted to who.
• the hydraulic power of the hydraulic pump can thus be matched to the power of the drive motor. If the device is designed to control a hydraulic motor, the hydraulic power of the hydraulic motor can be matched to the power drawn from the shaft.
• the control device can be designed to determine a position of the adjustment unit based on the pressure detected by the pressure sensor, it being possible for the high-pressure seat valve and/or the low-pressure seat valve to be activated taking into account the position of the adjustment unit determined by the control device.
• the adjusting unit is designed as an adjusting cylinder, the position of the adjusting unit is preferably described by the position of the piston in the adjusting cylinder.
• a swivel angle of the hydraulic pump or the hydraulic motor can also be determined via the position of the piston. With such an arrangement, the swivel angle can therefore be detected without a swivel angle sensor being available. As a result, a simpler construction of the hydraulic pump or the hydraulic motor can be achieved. In addition, an active influencing of the swivel angle can be made possible in this way.
• the high-pressure seat valve and/or the low-pressure seat valve can be activated by the control device using an activation variable.
• a reference value of the activation variable depending on the actual value of a parameter that can be influenced by the delivery volume of the hydraulic pump or by the displacement volume to be taken up by the hydraulic motor can be stored in the control device.
• the control device is preferably designed to use a value corresponding to the actual value of the parameter denden actual value of the activation variable and from the comparison of the actual value of the activation variable with a reference value of the activation variable associated with the actual value of the characteristic variable to determine a status characteristic value of the hydraulic pump or the hydraulic motor.
• a method for controlling the hydraulic pump of the hydraulic motor, wherein the high-pressure seat valve and/or a low-pressure seat valve can be activated using an activation variable comprises the following steps:
• the parameter can be the volume flow of the hydraulic fluid.
• the activation variable can be formed by the strength of a control current and/or a control duration of the high-pressure seat valve and/or the low-pressure seat valve or their activation frequencies and/or period duration.
• the drive current typically has a periodic curve, with the strength of the drive current changing during a period.
• the duration in which the drive current is so strong that it normally ment causes the valve to open is referred to here and in the following as the activation duration.
• a reference relationship between the volume flow and the strength of the control current and/or the control duration can be stored in the control device, so that the actual value of the control current and/or the control duration can be compared with a corresponding reference value for a specific volume flow.
• the reference context can be stored, for example, in the form of a characteristic curve or a characteristic map.
• the status characteristic can be specified, for example, in the form of a percentage deviation.
• the hydraulic pump or the hydraulic motor has higher leakage with increasing wear.
• the high-pressure seat valve In order to achieve the same effective delivery volume in the case of the hydraulic pump or the same mechanical power in the case of the hydraulic motor, the high-pressure seat valve must be opened more frequently or wider as a consequence. Based on the condition parameter, a statement can be made about the wear condition of the hydraulic pump or the hydraulic motor.
• FIG. 1 shows a first exemplary embodiment of a proposed device for controlling a hydraulic pump with a high-pressure seat valve
• FIG. 2 shows a second exemplary embodiment of a proposed device for controlling a hydraulic pump with a high-pressure seat valve and throttle
• FIG. 3 shows a third exemplary embodiment of a proposed device for controlling a hydraulic pump with a high-pressure seat valve and a low-pressure seat valve
• FIG. 4 shows a fourth exemplary embodiment of a proposed device for controlling a hydraulic pump with a high-pressure seat valve and a low-pressure seat valve, including pressure limitation
• FIG. 5 shows a fifth exemplary embodiment of a proposed device for controlling a hydraulic pump with a high-pressure seat valve and a low-pressure seat valve including pressure limitation
• FIG. 6 shows a sixth exemplary embodiment of a proposed device for controlling a hydraulic pump with a low-pressure seat valve and high-pressure throttle
• FIG. 7 shows an exemplary embodiment of a proposed device for controlling a hydraulic motor
• FIG. 8 shows a basic representation of a second embodiment of the adjustment unit
• FIG. 9 shows a seventh exemplary embodiment of a proposed device for controlling a hydraulic pump with a high-pressure seat valve and a low-pressure seat valve including pressure limitation and pressure sensor,
• FIG. 10 shows a basic representation of an embodiment of the control device for carrying out a drive to control a hydraulic pump or a hydraulic motor.
• FIG. 1 shows a first exemplary embodiment of a proposed device 10i for controlling a hydraulic pump 12 using a basic circuit diagram.
• the device 10i is part of a hydraulic system 14 with which an unspecified consumer 16 can be actuated and which can include hydraulic components such as valves, diaphragms and the like, which are not illustrated.
• the consumer 16 can, for example, be a hydraulic cylinder with which a component, for example of a construction machine, is moved.
• the device 10i includes a hydraulic fluid reservoir 18, in which a hydraulic fluid, in particular hydraulic oil, can be held. Furthermore, the device 10i comprises a hydraulic pump 12 which is equipped with an input 20 and an output 22 .
• the inlet 20 of the hydraulic pump 12 is connected to the hydraulic fluid reservoir 18 by means of a first low-pressure line 24 so that the hydraulic pump 12 can suck in the hydraulic fluid from the hydraulic fluid reservoir 18 .
• the outlet 22 of the hydraulic pump 12 is connected to the already mentioned consumer 16 by means of a high-pressure line 26 .
• the hydraulic fluid sucked in by the hyd pump 12 can be conveyed to the consumer 16 and a pressure can be built up there due to a resistance from the hydraulic system or the consumer 16 .
• the device 10i includes an adjustment unit 27 which interacts with the hydraulic pump 12 and can be structurally integrated into the hydraulic pump 12 .
• the delivery volume of the hydraulic pump 12 can be changed, ie the volume flow provided by the hydraulic pump 12 Vo.
• the Control unit 27 designed as a control cylinder 28, with wel chem the so-called pivot angle a can be changed. Since the pivot angle a can be changed in such a way that the delivery volume of the hydraulic pump 12 is changed between 0% (theoretically) and 100%.
• the term "pivot angle" is commonly used for axial piston pumps, although the use of the present device 10i is not limited to the regulation of axial piston pumps 28 is divided into a first pressure chamber 32 and a second pressure chamber 34.
• the first pressure chamber 32 is connected to the high-pressure line 26 by means of a high-pressure secondary line 36 and a working line 37, while the second pressure chamber 34 is connected to the hydraulic fluid already mentioned by means of a second low-pressure line 38 reservoir 18 is connected directly or indirectly to the housing of the hydraulic pump 12.
• the second low-pressure line 38 can also be referred to as a leakage line or tank line.
• the high-pressure secondary line 36 there is a high-pressure seat valve 40, designed as a high-pressure digital seat valve 41 in the present exemplary embodiment, which can be actuated with a control device 42, for which purpose electrical lines are used.
• a control device 42 for which purpose electrical lines are used.
• the high-pressure seat valve 40 By actuating the high-pressure seat valve 40, the pressure level in the downstream part of the high-pressure secondary line 36 can be influenced.
• This part of the high-pressure secondary line 36 is also referred to as the working line 37 in the fol lowing.
• the control device 42 is in turn connected to at least one sensor 44 using electrical lines. the one with which an actual value of a parameter can be determined and fed to the control device 42, which is to be changed with the delivery volume of the hydraulic pump 12. Furthermore, the control device 42 is connected using electrical lines to an actuator 46 with which the setpoint value of the parameter can be specified.
• the actuator 46 can be configured, for example, as an operating lever of the construction machine.
• the control device 42 can also be connected by means of electrical lines to one or more other sensors 48, with which or which parameters can be detected, which can have an influence on the control.
• the parameters can be taken into account by the control device 42 when the high-pressure seat valve 40 is actuated, in order to be able to adapt the actual value more quickly to the setpoint value.
• the sensor 44 and the other sensors 48 as well as the actuator 46 make their signals available to the control device 42 in electronic form. Wireless connections can also be provided instead of electrical lines.
• the proposed device 10i is operated in the following manner: First, a drive motor 62 for the hydraulic pump 12 is switched on, as a result of which the hydraulic pump 12 is activated fourth.
• the hydraulic pump 12 delivers the hydraulic fluid from the hydraulic fluid reservoir 18 to the consumer 16, in which a certain pressure builds up due to a resistance and the delivery of the fluid.
• This pressure is also present in the high-pressure line 26 and in the high-pressure secondary line 36 in front of the high-pressure seat valve 40, viewed in the direction of flow.
• In the working line 37 there is a lower pressure than in the high-pressure secondary line 36, in order to generate a balance of forces within the adjustment unit 27 .
• the user of the construction machine can now use the actuator 46 to specify a certain target value for the parameter, which can correspond to a specific volume flow of the hydraulic fluid in the consumer 16, for example.
• This target value is supplied to the control device 42 .
• the actual value of the parameter in the consumer 16 or at another suitable point in the hydraulic system 14 is detected by the sensor 44 .
• the high-pressure seat valve 40 is now actuated by the control device 42 .
• the high-pressure seat valve 40 is a 2/2 seat valve which can be moved between an open position and a closed position. It can also be seen from FIG. 1 that the high-pressure seat valve 40 is closed without current, i.e. it is designed as a “normally closed” valve. Due to the fact that the high-pressure seat valve 40 is designed as a seat valve, it is in the closed state leak free.
• the high-pressure seat valve 40 is not actuated by the control device 42 .
• the high-pressure seat valve 40 is closed.
• the pressure which is built up in the consumer 16 and consequently in the high-pressure line 26 and in the high-pressure secondary line 36 up to the high-pressure seat valve 40 is consequently not passed on to the first pressure chamber 32 .
• the restoring spring 39, with which the piston 30 is preloaded, is therefore in a state corresponding to the minimum spring preload.
• the Stellzy cylinder 28 acts together with the hydraulic pump 12 in such a way that the se assumes its maximum swivel angle a or delivers its maximum delivery volume.
• the pressure in the consumer 16, in the high-pressure line 26 and in the high-pressure secondary line 36 increases further. This increase in pressure is detected by sensor 44 . If the control device 42 determines that the actual value does not correspond to the setpoint value, the delivery volume of the hydraulic pump 12 can be reduced. For this purpose, the regulation device 42 opens the high-pressure seat valve 40 so that the hydraulic fluid can flow through the high-pressure seat valve 40 to the first pressure chamber 32 . The volume in the first pressure chamber 32 can be adjusted as a result of the pulse width with which the high-pressure seat valve 40 is opened and closed.
• the position of the piston would be retained. This would also mean that the delivery volume of the pump could not be increased again.
• the volume of the hydraulic fluid in the first pressure chamber 32 decreases more or less rapidly, as a result of which the piston 30 is pushed back to the first pressure chamber 32 by the return spring 39 .
• This shift has an increase in setting angle and consequent increase the displacement of the hydraulic pump 12 result. This would cause the actual value to deviate from the target value again.
• the control device 42 opens the high-pressure seat valve 40 in such a way that the actual value corresponds to the desired value.
• the delivery volume of the hydraulic pump 12 must be increased. In the exemplary embodiment illustrated in FIG. 1, this is effected exclusively via the leakage, which, as already mentioned, allows the hydraulic fluid to flow from the first pressure chamber 32 into the second pressure chamber 34 . As also described, the return spring 39 returns the piston 30 to the first pressure chamber 32, whereby the pivot angle a and the delivery volume are increased. In this way, the hydraulic pump 12 can be regulated accordingly. At this point it should be mentioned that with the further sensor 48 parameters can flow into the regulation, which also have an influence on the regulation.
• FIG. 2 shows a second exemplary embodiment of the proposed device IO2, also using a basic circuit diagram.
• the structure of the device IO2 according to the second exemplary embodiment corresponds largely to that of the first exemplary embodiment of the device 10i shown in Figure 1, with an additional low-pressure line 50 branching off from the high-pressure secondary line 36 between the high-pressure seat valve 40 and the actuating cylinder 28 and opens into the second low-pressure line 38 .
• a low-pressure throttle 52 is arranged in the water secondary low-pressure line 50. Through the secondary low-pressure line 50, the hydraulic fluid from the first pressure chamber 32 in the hydraulic fluid Reservoir 18 flow without having to flow into the second pressure chamber 34 between the piston 30 and the actuating cylinder 28 .
• the actuating cylinder 28 could therefore be designed without leakage, which is not possible in principle. However, the leakage can be reduced by appropriate manufacturing accuracy. Reduced leakage keeps the pressure loss in the hydraulic system 14 low, thereby increasing the efficiency with which the hydraulic system 14 can be operated.
• the piston 30 must be displaced towards the first pressure chamber 32 in order to increase the swivel angle a or the delivery volume of the hydraulic pump 12 , with a certain volume of the hydraulic fluid having to be discharged from the first pressure chamber 32 .
• the low-pressure throttle 52 flow out of the first pressure chamber 32 . Since the hydraulic fluid can flow out of the first pressure chamber 32 more quickly in the second exemplary embodiment, the control becomes more dynamic, with the result that the response behavior is improved.
• FIG. 3 shows a third exemplary embodiment of the device 10 3 according to the proposal, also using a basic circuit diagram.
• the device 10 3 according to the third exemplary embodiment is for the most part the same as the device IO2 according to the second exemplary embodiment shown in FIG low pressure Digital seat valve 55 is formed and how the high-pressure seat valve 40 can be actuated by the control device 42.
• the outflow of the hydraulic fluid from the first pressure chamber 32 can be influenced in a much more targeted manner in the third exemplary embodiment than in the second exemplary embodiment, since the volume flow of the hydraulic fluid flowing out of the first pressure chamber 32 can be specified with a corresponding activation of the low-pressure seat valve 54 can.
• the control device 42 can open the low-pressure seat valve 54 accordingly, as a result of which the swivel angle a or the delivery volume of the hydraulic pump 12 are increased .
• FIG. 4 shows a fourth exemplary embodiment of the proposed device IO4, which largely corresponds to the third exemplary embodiment according to FIG.
• the main difference is that the high-pressure seat valve 40 is designed as a high-pressure seat valve 56 with an integrated pressure limitation, in this case as a high-pressure digital seat valve 57 with an integrated pressure-limitation function.
• the high-pressure seat valve 40 therefore has a pressure-limiting function, the value of which can be designed to be variable depending on the system specifications. If the pressure in the consumer 16 and consequently in the high-pressure line 26 and the high-pressure secondary line 36 up to the high-pressure seat valve 40 exceeds a certain value, the high-pressure seat valve 40 opens regardless of whether it is activated accordingly by the control device 42 or Not.
• the hydraulic fluid flows into the first pressure chamber 32, as a result of which the piston 30 is displaced toward the second pressure chamber 34, as described above. ben and consequently the pivot angle a and the delivery volume of the hydraulic pump 12 are reduced.
• the pressure in the supply line can therefore not exceed the maximum pump pressure. Damage to the hydraulic components of the hydraulic system 14 can thereby be avoided.
• FIG. 5 shows a fifth exemplary embodiment of the proposed device IO5, which largely corresponds to the third exemplary embodiment according to FIG.
• a bypass line 58 is provided in the high-pressure secondary line 36, with which the high-pressure seat valve 40 can be bypassed.
• the hydraulic fluid can therefore flow both through the high-pressure seat valve 40 and through the bypass line 58 in the first pressure chamber 32 .
• a pressure relief valve 60 is arranged in the bypass line 58 .
• the swivel angle a and the delivery volume of the hydraulic pump 12 are reduced as a result of the opening of the pressure-limiting valve 60, so that the pressure in the hydraulic system 14 is limited.
• FIG. 6 shows a sixth exemplary embodiment of the proposed device IOe, in which the high-pressure secondary line 36 opens directly into the first pressure chamber 32 without a high-pressure seat valve 40 being arranged in the high-pressure secondary line 36 here.
• a high-pressure throttle 64 is arranged in the high-pressure secondary line 36 .
• a low-pressure seat valve 54 is arranged, which, as in the relevant previously described exemplary embodiments, is controlled by the control device 42 can be operated.
• the device 10e according to the sixth exemplary embodiment is operated as follows: As a result of the conveyance of the hydraulic fluid from the hydraulic reservoir 18 to the consumer 16, the pressure in the consumer 16, which is also present in the high-pressure secondary line 36, increases.
• the throttle of the high pressure 64 correspondingly reduced pressure.
• the reduced pressure in the first pressure chamber 32 also reduces the swivel angle a and the delivery volume of the hydraulic pump 12, as has already been described several times open.
• FIG. 7 shows a device 72 for controlling a hydraulic motor 66, the device 72 largely corresponding to the device 10 3 for controlling a hydraulic pump 12 according to the third exemplary embodiment illustrated in FIG.
• the high-pressure line 26 is not connected to a consumer 16, but to a hydraulic fluid pressure reservoir 74, in which the hydraulic fluid is held at a certain pressure.
• the high-pressure line 26 is connected to the input 20 of the hydraulic motor 66 .
• the output 22 of the hydraulic motor 66 is connected to the hydraulic fluid reservoir 18 by means of a return line 68 .
• the hydraulic fluid therefore flows from the hydraulic fluid pressure reservoir 74 to the hydraulic fluid reservoir 18 and flows through the hydraulic motor 66.
• a shaft 70 is driven, which in turn is connected to a consumer 76. With the power transmitted by the shaft 70, the load 76 can be operated in the desired manner. Otherwise, the control of the hydraulic motor takes place 66 or the power delivered by it in the same way as has been described for the device 10 3 for controlling the hydraulic pump 12 according to the third exemplary embodiment. All exemplary embodiments of the device 10i to 10e for controlling the hydraulic pump 12 can also be used analogously as a device 72 for controlling the hydraulic motor 66.
• the control device 42 can include power electronics that can be operated with software. Algorithms that simulate various control characteristics can be stored in this software. As a result, the control device 42 can be operated, for example, as a PI controller, a PID controller or one of the above in combination with fixed-value control. The various control characteristics can be selected on the control device 42 depending on the application. An adjustment or replacement of the com ponents of the device 10 is not necessary.
• the number of sensors 44 and the additional sensors 48 is not limited. The measurement units they measure can also be largely freely selected, the only restriction for the measurement units determined by the sensors 44 having to be guaranteed that these can actually also be influenced by the hydraulic pump 12 or the hydraulic motor 66 .
• high-pressure line “low-pressure line” and the like are not to be understood in such a way that a high pressure or a low pressure must always be present there. These terms are primarily used to distinguish the respective components of the present devices 10 and 72.
• the high-pressure secondary line 36, the working line 37, the second low-pressure line 38, the secondary low-pressure line 50 and the bypass line 58 are shown in dashed lines. This is intended to symbolize that these lines are control lines that are used to control the hydraulic pump 12 or the hydraulic motor 66 and not primarily to supply the consumer 16 with hydraulic fluid.
• FIGS. 1 to 7 and 9 open circuits are shown in FIGS. 1 to 7 and 9 with and without preloaded tank pressure, although the proposed device for controlling a hydraulic pump 12 or the hydraulic motor 66 can also be used for closed circuits.
• FIG. 8 A second embodiment of the adjustment unit 27 is shown in FIG. 8 on the basis of a basic representation. While the piston 30 of the adjustment unit 27 according to the first embodiment is, as mentioned, pretensioned with the return spring 39 against the first pressure chamber 32, in the second embodiment of the adjustment unit 27 a counter-piston 78 is used for this purpose, which is slidably mounted in a counter-cylinder 79 . In order for the adjustment unit 27 to function even at lower pressures, the effective area of the counter-cylinder 79 is smaller than that of the actuating cylinder 28, for example in a ratio of 1:4. The counter-piston 78 closes off a first counter-pressure chamber 80 .
• the piston 30 is connected to the counter-piston 78 via a rotatably mounted connecting rod 86, which represents a pivoting cradle in the case of the axial piston pump. If the piston 30 is displaced towards the second pressure chamber 34 due to an increase in the pressure in the first pressure chamber 32, the connecting rod 86 transmits this movement to the counter-piston 78 in such a way that the counter- Piston 78 is moved in the opposite direction to the first counter-pressure chamber 80 out.
• the medium contained therein which can correspond to the hydraulic fluid of the rest of the device 10, is displaced in the process. With the active supply of the first counter-pressure chamber 80 with the medium, the piston 30 is moved back toward the first pressure chamber 32 .
• the counter-piston 78 divides the counter-cylinder 79 into the already mentioned first counter-pressure chamber 80 and a second counter-pressure chamber 82 .
• the first counter-pressure chamber 80 and the second counter-pressure chamber 82 can be integrated into the device 10 so that the pressures in the first counter-pressure chamber 80 and in the second counter-pressure chamber 82 can be changed in a targeted manner in order to be able to implement certain control characteristics.
• the piston 30 and the counter-piston 78 have a specific area ratio in order to generate a dominance of a piston 30 at the same pressure level.
• the combination of counter-piston 78 with an additional spring for resetting the piston 30 can also be implemented (not shown).
• FIG. 9 shows a seventh exemplary embodiment of the device IO 7 according to the proposal, which largely corresponds to the fourth exemplary embodiment according to FIG.
• the main difference is that the pressure present in the working line 37 can be detected by means of a pressure sensor 88 .
• the pressure sensor 88 interacts with the control device 42 in such a way that the high-pressure seat valve 40 and/or the low-pressure seat valve 54 can be activated taking into account the pressure detected by the pressure sensor 88 .
• the pressure in the working line 37 can be included as an additional parameter in the regulation of the system.
• the pressure recorded in the working line 37 corresponds to the pressure which rests against the adjustment unit 27 .
• the adjustment unit 27 can be influenced more directly by the regulation device 42 .
• the adjustment unit 27 generally sets the delivery volume of the hydraulic pump 12 . If other parameters of the hydraulic pump are known, any arbitrary delivery volume can be impressed on the hydraulic pump 12 with the device of this type.
• the hydraulic power of the hydraulic pump 12 can be matched to the power of the propulsion engine sector 62.
• the control device 42 can be designed to determine the position of the piston 30 in the actuating cylinder 28 based on the pressure detected by the pressure sensor 88, so that the high-pressure seat valve 40 and/or the low-pressure seat valve 54, taking into account the 42 he determined position of the piston 30 can be activated. Furthermore, the swivel angle of the hydraulic pump 12 can be determined via the position of the piston 30 . With such an arrangement, the swivel angle can therefore be detected without a swivel angle sensor being available. A simpler construction of the hydraulic pump 12 can thereby be achieved. In addition, an active influencing of the swivel angle can be made possible in this way.
• the detection of the pressure present in the working line 37 and the interaction of the pressure sensor 88 with the control device 42 can be applied to the exemplary embodiments illustrated in FIGS. 1, 2 and 4 to 6 in accordance with the manner described above.
• the pressure sensor 88 can also interact with the control device 42 in such a way that the high-pressure seat valve 40 and/or the Low-pressure seat valve 54 can be activated taking into account the pressure detected by the pressure sensor 88 .
• the device as shown in FIG. 7, is designed to control a hydraulic motor 66
• the pressure present in the working line 37 can be detected in a corresponding manner by means of the pressure sensor 88.
• the hydraulic motor 66 can be given any desired absorption volume.
• the hydraulic power of the hydraulic motor 66 can thus be matched to the power taken from the shaft 70 .
• the swivel angle of the hydraulic motor 66 can also be detected and actively influenced in a corresponding manner.
• the high-pressure seat valve 40 and/or the low-pressure seat valve 54 can be activated using an activation variable by the control device 42 as shown in FIG.
• a reference value 92 of the activation variable depending on the actual value 94 of a parameter that can be influenced by the delivery volume of the hydraulic pump 12 or by the displacement volume to be taken up by the hydraulic motor 66 can be stored in the control device 42 .
• Control device 42 is preferably designed to record actual value 94 of the parameter and a corresponding actual value 90 of the activation variable, and from the comparison of actual value 90 of the activation variable with reference value 92 associated with actual value 94 of the characteristic Activation variable to determine a state parameter 96 of the hydraulic pump 12 or the hydraulic motor 66 stuffs.
• a particular advantage of such a development of the invention is that no further components are required for its implementation, but only the control device 42 must be adjusted accordingly.
• a method for controlling the hydraulic pump 12 of the hydraulic motor 66, wherein the high-pressure seat valve 40 and/or a low-pressure seat valve 54 can be activated based on an activation variable comprises a first step 101, in which the actual value 94 includes at least one the delivery volume of the hydraulic pump 12 or with the intake volume to be taken up by the hydraulic motor 66 which can be influenced parameter is detected.
• an actual value 90 of the activation variable which corresponds to the actual value of the characteristic variable, is also recorded in order to determine a state characteristic value 96 of the hydraulic pump 12 or the hydraulic motor 66 in a third step 103 by comparing the actual value 90 of the Activation quantity with a reference value 92 of the activation quantity associated with the actual value 94 of the parameter.
• the parameter can be the volume flow of the hydraulic fluid.
• the activation variable can be formed by the strength of a control current and/or a control duration of the high-pressure seat valve and/or the low-pressure seat valve or their activation frequencies and/or period duration. Accordingly, a reference relationship 98 between an actual volume flow 94a and an actual intensity 90a of the activation current and/or an actual activation duration 90b can be stored in control device 42, so that the actual intensity for a specific value of actual volume flow 94a 90a of the drive current and/or the actual drive duration 90b can be compared with a corresponding reference value 92.
• the status parameter 96 can be specified, for example, in the form of a percentage deviation.
• actuator 48 additional sensor 50 secondary low-pressure line 52 low-pressure throttle

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Fluid-Pressure Circuits (AREA)
• Control Of Positive-Displacement Pumps (AREA)

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ID=81344470

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• 2021
  • 2021-03-30 DE DE102021108081.9A patent/DE102021108081B4/de active Active
• 2022
  • 2022-03-22 EP EP22717577.5A patent/EP4118334A1/de active Pending
  • 2022-03-22 WO PCT/EP2022/057550 patent/WO2022207416A1/de unknown
  • 2022-03-22 CN CN202280006185.XA patent/CN116234983A/zh active Pending

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