EP3807534B1 - Hydraulic drive system for a construction material pump, and construction material pump - Google Patents

Description

FIELD OF APPLICATION AND PRIOR ART

The invention relates to a hydraulic drive system for a building material pump and a building material pump having such a hydraulic drive system.

The DE 101 34 789 A1 discloses a travel drive with an internal combustion engine and with working hydraulics, which has a pump device actuated by the internal combustion engine, and with an electronic control unit that controls the speed of the internal combustion engine and the flow rate of the pump device. The working hydraulics have a hydraulic load branch that can be switched on by means of a control element, and the control element can be activated by the electronic control unit as soon as a detected actual speed of the internal combustion engine exceeds a tolerance range of a set target speed. Use for tracked vehicles on snow slopes.

TASK AND SOLUTION

The object of the invention is to provide a hydraulic drive system for a building material pump and a building material pump having such a hydraulic drive system which has improved properties in each case.

The invention solves this problem by providing a hydraulic drive system with the features of claim 1 and a building material pump with the features of claim 14. Advantageous developments and/or refinements of the invention are described in the dependent claims.

The hydraulic drive system according to the invention for a building material pump has a hydraulic circuit, in particular at least one feed pump, at least one, in particular electrically, controllable pressure relief valve unit and a, in particular electrical, control unit. The hydraulic circuit is designed for hydraulic fluid, in particular oil. The feed pump, in particular at least one, is designed for feeding hydraulic fluid into the hydraulic circuit, in particular automatically. The pressure-limiting valve unit is for, in particular, automatic, variable or changeable or controllable setting, in particular at least one limit pressure, in particular a limit pressure value or Limit pressure amount, formed by hydraulic fluid of at least one section of the hydraulic circuit within a pressure range, in particular a pressure value range, in particular in or during operation of the hydraulic drive system, in particular delivery operation of the building material pump. The at least one pressure-limiting valve unit has, in particular, at least one, in particular electrically, controllable proportional pressure-limiting valve. The proportional pressure-limiting valve is designed for the, in particular automatic, continuous setting of the limit pressure, in particular its value, of hydraulic fluid in at least one section of the hydraulic circuit within the pressure range. The control unit is designed to actuate the pressure-limiting valve unit, in particular automatically, as a function of at least one, in particular user-desired, operating parameter, in particular an operating parameter value or operating parameter amount, of the hydraulic drive system and/or hydraulic fluid in such a way that the pressure-limiting valve unit exceeds the limit pressure of the section of the hydraulic circuit, in particular variable, adjusted. The control unit is designed to actuate the proportional pressure relief valve, in particular automatically, as a function of the at least one operating parameter, such that the proportional pressure relief valve sets the limit pressure of the section of the hydraulic circuit, in particular continuously.

This enables a needs-based or adaptive setting or adjustment, in particular a reduction, of the limit pressure. The feed pump can overcome the limit pressure or have to work against it. This thus enables energy or power consumption of the feed pump to meet requirements, in particular a reduction in the energy or power consumption of the feed pump. This enables energy or power to be saved.

In particular, when there is a change in the at least one operating parameter or its value, the limit pressure or its value can be changed, in particular actively. Additionally or alternatively, if there is no change in the operating parameter or its value, the limit pressure or its value does not need to be changed. In other words: if there is no change in the operating parameter, the limit pressure or its value can be set constant or kept constant or left unchanged. In other words: the limit pressure or its value and the at least one operating parameter or its value can be linked to one another, in particular by means of a function.

The hydraulic circuit can have at least one hydraulic line, in particular a pipe and/or a hose.

The hydraulic drive system can have a container or tank, in particular a reservoir, for or with hydraulic fluid. The feed pump can be designed to feed in hydraulic fluid from the container. Additionally or alternatively, the feed pump can be a fixed displacement pump. Furthermore, additionally or alternatively, the feed pump can be designed for direct and/or indirect feeding into the at least one section.

The pressure relief valve unit can be referred to as a pressure control unit. In particular, the hydraulic drive system can have at least one, in particular electrical, pressure sensor. The pressure sensor can be designed for, in particular automatic, measurement, in particular regulation, of the limit pressure, in particular the limit pressure value or limit pressure amount, of hydraulic fluid in the section of the hydraulic circuit. The control unit and/or the pressure-limiting valve unit can be designed to set, in particular regulate, the limit pressure as a function of the measured limit pressure. In particular, the control unit and/or the pressure-limiting valve unit, in particular in each case, can have a signal connection, in particular an electrical signal connection, with the pressure sensor. Additionally or alternatively, this can be referred to as pressure regulation. Furthermore, additionally or alternatively, the pressure-limiting valve unit can be designed to set the limit pressure to at least three different limit pressure values. In particular, the pressure-limiting valve unit can be designed to adjust the limit pressure in pressure value increments of a maximum of 5 bar, in particular a maximum of 4 bar, in particular a maximum of 3 bar, in particular a maximum of 2 bar, in particular a maximum of 1 bar, in particular for continuous adjustment. Furthermore, additionally or alternatively, the pressure range can have a minimum limit pressure value and a maximum limit pressure value or be defined by them.

In particular, the proportional pressure relief valve can be referred to as a proportional pressure control valve.

The operating parameter or its value can change in stages, in particular continuously.

The control unit can have a user-actuable control panel for operating the hydraulic drive system, in particular the building material pump, in particular an input device for user input or user selection of the at least one operating parameter or its value. Additionally or alternatively, the control unit can be designed to determine or determine, in particular automatically, in particular a calculation, of the limit pressure or its value as a function of the at least one operating parameter. In other words: the limit pressure can depend on the at least one operating parameter and/or must have a specific or required value in order to achieve the operating parameter, which is particularly desired by the user. In particular, the control unit can have a processor and/or a memory. Furthermore, additionally or alternatively, the control unit can have a signal connection, in particular an electrical signal connection, with the pressure-limiting valve unit.

In a development of the invention, the hydraulic drive system has a drive motor. The drive motor is designed to drive the feed pump, in particular automatically. The needs-based setting of the limit pressure or its value enables a needs-based energy or power consumption of the drive motor. In particular, the drive motor can be an internal combustion engine, in particular a diesel engine, or an electric motor.

In one development of the invention, the at least one operating parameter is a drive state, a drive flow, a drive pressure, a drive speed, a cooling flow, a temperature and/or a degree of contamination. In particular, the drive state can be on or off or drive or non-drive, in particular of the building material pump. When the drive state is off, the limit pressure can be lowered, in particular to the minimum limit pressure value. In addition or as an alternative, the drive flow and/or the drive pressure can each have a value or absolute value, in particular a variable value, and/or be an operating parameter of the hydraulic fluid. Furthermore, additionally or alternatively, the drive speed can have an in particular variable value or amount and/or be an operating parameter of the feed pump and/or the drive motor, if present. Furthermore, additionally or alternatively, the cooling flow, the temperature and/or the degree of contamination can each have a, in particular variable, value or amount and/or be an operating parameter of the hydraulic fluid.

In a development of the invention, the pressure range is from a minimum of 2.5 bar to a maximum of 40 bar, in particular from a minimum of 5 bar to a maximum of 35 bar, in particular from a minimum of 10 bar to a maximum of 30 bar, in particular from a minimum of 15 bar to a maximum of 25 bar .

In a development of the invention, the at least one section of the hydraulic circuit has a feed pressure section for hydraulic fluid. The at least one pressure-limiting valve unit has a feed pressure-limiting valve unit that can be actuated, in particular electrically. The feed pressure limiting valve unit is designed for the, in particular automatic, variable setting of a feed limit pressure, in particular a feed limit pressure value or a feed limit pressure amount, of hydraulic fluid of the feed pressure section within the pressure range. In particular, the control unit can be designed to actuate the feed pressure limiting valve unit, in particular automatically, depending on the at least one operating parameter, in such a way that the feed pressure limiting valve unit adjusts the feed limit pressure of the feed pressure section, in particular variably. The supply limit pressure or its value can depend on the drive condition, the drive flow, the drive pressure, the drive speed, the cooling flow, the temperature and/or the degree of contamination, if any. Additionally or alternatively, the boost pressure limiting valve unit can be referred to as a boost pressure control unit. Furthermore, additionally or alternatively, the feed pump can be designed for immediate or direct feeding into the feed pressure section.

In one development of the invention, the hydraulic drive system has, in particular, at least one variably adjustable drive pump and at least one, in particular electrically controllable, hydraulic pressure-based actuator. The drive pump is for, in particular automatically, generating a, in particular, variable drive flow, in particular with a variable drive flow value or drive flow amount, with a, in particular, variable drive pressure, in particular with a variable drive pressure value or drive pressure amount, of hydraulic fluid in at least one drive pressure section of the hydraulic circuit educated. The actuator is designed for the, in particular automatic, variable adjustment of the drive pump by means of a variable control pressure, in particular with a variable control pressure value or control pressure amount, of hydraulic fluid. The at least one section, in particular the feed pressure section, if present, of the hydraulic circuit is designed for the, in particular automatic, hydraulic pressure supply of the at least one actuator with hydraulic fluid at the set limit pressure, in particular the set feed limit pressure, if present, for the control pressure. The control unit is there designed to control the at least one actuator, in particular automatically, as a function of the at least one operating parameter, in such a way that the at least one actuator adjusts the drive pump, in particular variably, to generate the variable drive flow with the variable drive pressure of hydraulic fluid in the at least one drive pressure section.

In particular, the drive pressure section can be referred to as a high and/or low pressure section. Additionally or alternatively, the drive pressure section may be different from the feed pressure section, if any. In particular, the feed pressure section can be designed to feed hydraulic fluid into the drive pressure section, in particular by means of at least one feed check valve of the hydraulic drive system. In other words: the feed pump can be designed for direct or indirect feeding into the drive pressure section.

Furthermore, additionally or alternatively, the drive speed, if present, can be an operating parameter of the drive pump. In particular, the drive motor can be designed to drive the drive pump, in particular automatically.

Furthermore, additionally or alternatively, the actuating pressure can depend on the operating parameter, in particular on the drive state, the drive flow, the drive pressure and/or the drive speed, and/or must have a specific or required value in order to achieve the operating parameter, which is particularly desired by the user. In particular, the control unit can be designed to determine or determine, in particular automatically, in particular a calculation, of the control pressure or its value as a function of the at least one operating parameter.

Furthermore, additionally or alternatively, the limit pressure, in particular the feed pressure, if present, can be dependent on the control pressure and/or must have a specific or required value in order to achieve the control pressure. In particular, the control unit can be designed to determine or determine, in particular automatically, in particular a calculation, of the limit pressure or its value as a function of the control pressure. Furthermore, additionally or alternatively, the control unit can have a signal connection, in particular a hydraulic one, with the actuator.

In particular, in the power off state, if any, the power pump only needs to generate a relatively low power flow or even no power flow at all. Thus, only a relatively low control pressure or no control pressure can be required for the adjustment of the drive pump. Therewith the limit pressure can be lowered, in particular to the minimum limit pressure value. The minimum limit pressure value can make it possible to maintain a function of the drive pump or to avoid damage to the drive pump. With the drive state on, if present, a relatively higher actuating pressure may be required, in particular as a function of the drive flow, the drive pressure and/or the drive speed. Thus, a relatively higher confining pressure may be required.

Furthermore, additionally or alternatively, the drive pump can be an axial piston pump with a variably adjustable displacement. The at least one actuator can be designed for, in particular automatic, variable adjustment of the displacement.

In one embodiment of the invention, the drive pump is an axial piston pump with a variably adjustable swash plate. The at least one actuator is designed for, in particular automatic, variable adjustment of the swash plate. In particular, a swivel angle of the swash plate can depend on the operating parameter, in particular on the drive state and/or the drive flow, and/or must have a specific or required value in order to achieve the operating parameter, which is particularly desired by the user. In particular, the control unit can be designed to determine or determine, in particular automatically, in particular a calculation, of the swivel angle or its value as a function of the at least one operating parameter.

In one embodiment of the invention, the hydraulic drive system has at least one drive cylinder and an associated drive piston, which is arranged in particular in the drive cylinder. The drive pump is designed by generating the drive flow of hydraulic fluid for the, in particular automatic, variable movement of the at least one drive piston, in particular in the drive cylinder. In particular, the hydraulic drive system can have at least one pump line. The drive pump and the drive cylinder can be connected by means of the pump line for a flow of hydraulic fluid, in particular between the drive pump and the drive cylinder. In addition or as an alternative, the drive piston can be designed to be pressurized with hydraulic fluid. Furthermore, additionally or alternatively, the control unit can be designed to control the movement of the drive piston, in particular automatically, as a function of the at least one operating parameter.

In one embodiment, the hydraulic drive system has at least two drive cylinders and associated ones, in particular arranged in the respective drive cylinder Drive piston and a swing line for hydraulic fluid. The drive pump and the two drive cylinders form a closed drive circuit for hydraulic fluid by means of the swing line. The two drive pistons are coupled by means of the swing line, in particular in phase opposition. In particular, the two drive cylinders can be connected by means of the swing line for a flow of hydraulic fluid, in particular between the drive cylinders. Additionally or alternatively, the hydraulic drive system can have at least two pump lines. The drive pump and the two drive cylinders can form the closed drive circuit for hydraulic fluid by means of the swing line and the two pump lines. In particular, the drive pump and one of the two drive cylinders can be connected by means of one of the two pump lines for a flow of hydraulic fluid, in particular between the drive pump and the drive cylinder. The drive pump and another of the two drive cylinders can be connected by means of another of the two pump lines for a flow of hydraulic fluid, in particular between the drive pump and the drive cylinder. Furthermore, additionally or alternatively, the drive pump or the closed drive circuit can have a high-pressure side and a low-pressure side, which in particular can be cyclically interchanged, in particular in or during operation of the hydraulic drive system, in particular delivery operation of the building material pump. In particular, the drive pressure can be referred to as high pressure, in particular on the high pressure side. A low pressure or low limit pressure, in particular on the low-pressure side, can be produced or generated by the feed pump, in particular the feed limit pressure, if present. The drive pressure or high pressure or its value can be higher than the low pressure or low limit pressure or its value. In particular, a closed drive circuit can refer to a flow of hydraulic fluid from the drive pump, in particular its high-pressure side, through the one pump connection, the one drive cylinder, the swing connection, the other drive cylinder, the other pump connection to the drive pump, in particular its low-pressure side.

In a development of the invention, the at least one section of the hydraulic circuit has at least one low-pressure section for hydraulic fluid. The at least one pressure relief valve unit has a low-pressure relief valve unit that can be actuated, in particular electrically. The low-pressure limiting valve unit is designed for the, in particular automatic, variable setting of a low-limit pressure, in particular a low-limit pressure value or low-limit pressure amount, of hydraulic fluid in the at least one low-pressure section within the pressure region. In particular, the control unit can be designed to, depending on the at least one operating parameter to control the low-pressure limiting valve unit, in particular automatically, in such a way that the low-pressure limiting valve unit sets the low-limit pressure of the at least one low-pressure section, in particular variably. The low-limit pressure or its value can depend on the cooling flow, the temperature and/or the degree of contamination, if any. Additionally or alternatively, the low-pressure relief valve unit can be referred to as a low-pressure control unit. Further additionally or alternatively, the low-pressure section can be referred to as the drive pressure section. Further additionally or alternatively, the low pressure section may be different from the boost pressure section, if any. In particular, the feed pressure section can be designed to feed hydraulic fluid into the low-pressure section, in particular by means of at least one feed check valve of the hydraulic drive system. In other words: the feed pump can be designed for direct or indirect feeding into the low-pressure section. In other words: the low limit pressure or its value can be lower than the feed limit pressure or its value. Furthermore, additionally or alternatively, the hydraulic drive system can have an alternating scavenging valve. The low-pressure section and the low-pressure relief valve unit can be connected by means of the shuttle flushing valve for a flow of hydraulic fluid, in particular from the low-pressure section to the low-pressure relief valve unit.

In a development of the invention, the hydraulic drive system has a cooler. The cooler is designed for, in particular automatic, cooling of hydraulic fluid. The at least one pressure-limiting valve unit is designed by setting the limit pressure for the, in particular automatic, variable setting of, in particular, the cooling flow of hydraulic fluid via or through the cooler. The control unit is designed to actuate the pressure limiting valve unit, in particular automatically, as a function of the at least one operating parameter, in particular the temperature, if present, in such a way that the pressure limiting valve unit adjusts the cooling flow of hydraulic fluid via the cooler, in particular variably. This enables a needs-based or adaptive setting or adjustment, in particular a reduction, of the cooling flow. This thus enables energy or power consumption of the feed pump to meet requirements, in particular a reduction in the energy or power consumption of the feed pump. In particular, the cooling flow or its value can be adjusted or defined via or by a pressure difference between the feed limit pressure and the low limit pressure, if any. In other words: the low limit pressure can be in Depending on the cooling flow required, in particular, and the feed limit pressure required, in particular, be set. Additionally or alternatively, the hydraulic drive system can be designed to flush out or discharge the cooling flow from the hydraulic circuit, in particular the section, in particular the low-pressure section, in particular the closed drive circuit, if present, via the cooler.

In a further development of the invention, the at least one pressure-limiting valve unit is, in particular, automatically and/or variably flushed or discharged hydraulic fluid out of the hydraulic circuit, in particular the section, in particular to the feed pump and/or into the container, if present variable setting of the limit pressure formed. In particular, the pressure-limiting valve unit can be designed as a throttle valve unit.

In a development of the invention, the hydraulic drive system has at least one, in particular electrical, measuring sensor. The measuring sensor is designed for the, in particular automatic, measurement of at least one property, in particular a value or magnitude of the property and/or one, in particular the, temperature and/or one, in particular the, degree of contamination, of the hydraulic drive system and/or hydraulic fluid. The control unit is designed to determine, in particular automatically, the at least one operating parameter as a function of the measured property. In particular, the control unit can have a signal connection, in particular an electrical signal connection, to the measuring sensor. Additionally or alternatively, the operating parameter can correspond to or be the measured property.

Furthermore, the invention relates to a building material pump. The building material pump according to the invention has a building material delivery unit and the hydraulic drive system. The building material delivery unit is designed for, in particular automatic, delivery of building material. The hydraulic drive system is designed to drive the building material conveyor unit, in particular automatically.

The building material pump can enable the same advantages as the previously described hydraulic drive system.

In particular, the building material pump or the building material delivery unit or the building material can have at least one, in particular variable or variable funding parameters, in particular with a value or amount. In particular, the at least one delivery parameter can be a delivery condition, a delivery flow and/or a delivery pressure. Additionally or alternatively, the at least one operating parameter can be dependent on the at least one delivery parameter and/or must have a specific or required value in order to achieve the delivery parameter, which is particularly desired by the user. In particular, the drive status can depend on the delivery status, the drive flow can depend on the delivery flow and/or the drive pressure can depend on the delivery pressure, if present. In other words: the control unit can be designed to determine or determine, in particular automatically, in particular a calculation, of the at least one operating parameter or its value as a function of the at least one delivery parameter. Furthermore, additionally or alternatively, the control unit can have a user-actuable control panel for operating the building material pump or the hydraulic drive system, in particular an input device for user input or user selection of the at least one delivery parameter or its value.

Furthermore, additionally or alternatively, the building material pump can be referred to as a concrete pump or thick matter pump. Thick material can refer to mortar, cement, screed, concrete, plaster and/or mud.

Furthermore, additionally or alternatively, the device can be designed as a mobile device, in particular as a car building material pump.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1

einen schematischen Schaltplan eines erfindungsgemäßen Hydraulikantriebssystems einer erfindungsgemäßen Baustoffpumpe und

Fig. 2

einen schematischen Schaltplan eines Ausschnitts des Hydraulikantriebssystems der Fig. 1 und einer Baustofffördereinheit der erfindungsgemäßen Baustoffpumpe.

Further advantages and aspects of the invention result from the claims and from the following description of preferred exemplary embodiments of the invention, which are explained below with reference to the figures. show:

1

a schematic circuit diagram of a hydraulic drive system according to the invention of a building material pump according to the invention and

2

a schematic circuit diagram of a section of the hydraulic drive system 1 and a building material delivery unit of the building material pump according to the invention.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

The building material pump 200 according to the invention has a building material delivery unit 210 and a hydraulic drive system 100 according to the invention. The building material delivery unit 210 is designed to deliver building material BS. The hydraulic drive system 100 is designed to drive the building material conveyor unit 210 .

The hydraulic drive system 100 has a hydraulic circuit 101, a feed pump 2, at least one controllable pressure relief valve unit 6, 24 and a control unit 27, as in FIG 1 shown. The hydraulic circuit 101 is designed for hydraulic fluid HF. The feed pump 2 is designed to feed hydraulic fluid HF into the hydraulic circuit 101 . The pressure-limiting valve unit 6, 24 is designed to variably set a limit pressure p30, p31/32 of hydraulic fluid HF in at least one section 30, 31, 32 of the hydraulic circuit 101 within a pressure range pmin, pmax. The control unit 27 is designed to control the pressure-limiting valve unit 6, 24 as a function of at least one operating parameter BP of the hydraulic drive system 100 and/or hydraulic fluid HF in such a way that the pressure-limiting valve unit 6, 24 exceeds the limit pressure p30, p31/32 of the section 30, 31, 32 of the hydraulic circuit 101 adjusts.

In particular, the control unit 27 has an electrical signal connection with the pressure-limiting valve unit 6 , 24 .

In detail, the at least one operating parameter BP is a drive state, a drive flow, a drive pressure, a drive speed, a cooling flow, a temperature T and/or a degree of contamination.

The pressure range extends from a minimum of 10 bar pmin to a maximum of 35 bar pmax. In alternative exemplary embodiments, the pressure range can range from a minimum of 2.5 bar to a maximum of 40 bar.

In the exemplary embodiment shown, the at least one pressure-limiting valve unit 6, 24 has a controllable proportional pressure-limiting valve. The proportional pressure relief valve 6, 24 is designed to continuously adjust the limit pressure p30, p31/32 of hydraulic fluid HF in at least one section 30, 31, 32 of the hydraulic circuit 101 within the pressure range pmin, pmax. The control unit 27 is designed to control the proportional pressure relief valve 6, 24 as a function of the at least one operating parameter BP in such a way that the proportional pressure relief valve 6, 24 sets the limit pressure p30, p31/32 of the section 30, 31, 32 of the hydraulic circuit 101.

In alternative exemplary embodiments, the at least one pressure-limiting valve unit does not need to have a proportional pressure-limiting valve, or the at least one pressure-limiting valve unit can be configured differently.

In the exemplary embodiment shown, the hydraulic drive system 100 has two controllable pressure-limiting valve units 6, 24. In alternative exemplary embodiments, the hydraulic drive system does not need to have two controllable pressure-limiting valve units or the hydraulic drive system can only have a single controllable pressure-limiting valve unit or at least three controllable pressure-limiting valve units.

In particular, the hydraulic drive system, in particular instead of the pressure-limiting valve unit 6, can have a throttle valve unit, in particular a controllable one, in particular a proportional throttle valve. The throttle valve unit can be designed to variably adjust a flow of hydraulic fluid. The control unit can be designed to control the throttle valve unit depending on the at least one operating parameter of the hydraulic drive system and/or hydraulic fluid in such a way that the throttle valve unit can adjust the flow.

In detail, the at least one section of the hydraulic circuit 101 has a feed pressure section 30 for hydraulic fluid HF. The pressure limiting valve unit 24 has a boost pressure limiting valve unit or is a boost pressure limiting valve unit. The charge pressure limiting valve unit 24 is designed for the variable setting of a charge limit pressure p30 of hydraulic fluid HF of the charge pressure section 30 within the pressure range pmin, pmax.

In the exemplary embodiment shown, the feed pump is designed for the direct feeding of hydraulic fluid HF from a container 50 of the hydraulic drive system 100 into the feed pressure section 30, as indicated by an arrow.

In addition, the at least one section of the hydraulic circuit 101 has at least one low-pressure section 31, 32 for hydraulic fluid HF. The pressure relief valve unit 6 has a controllable low-pressure relief valve unit or is one Low pressure relief valve assembly. The low-pressure limiting valve unit 6 is designed to variably set a low-limit pressure p31/32 of hydraulic fluid HF in the at least one low-pressure section 31, 32 within the pressure range pmin, pmax. In alternative exemplary embodiments, the hydraulic drive system can have a throttle valve unit, in particular the throttle valve unit, in particular instead of the low-pressure limiting valve unit.

In the exemplary embodiment shown, the feed pressure section 30 is designed to feed hydraulic fluid HF into the low-pressure section 31, 32, as indicated by an arrow, in particular by means of at least one feed check valve 3, 4 of the hydraulic drive system 100.

Furthermore, in the exemplary embodiment shown, the hydraulic circuit 101 has two low-pressure sections or high-pressure sections or drive pressure sections 31 , 32 . In addition, the hydraulic drive system 100 has two feed check valves 3, 4.

Furthermore, the hydraulic drive system 100 has a variably adjustable drive pump 1 and at least one hydraulic pressure-based actuator 22, 23, in particular in the form of an actuating cylinder. The drive pump 1 is designed to generate a variable drive flow with a variable drive pressure of hydraulic fluid HF in at least one, in particular the drive pressure section 31, 32 of the hydraulic circuit 101. The actuator 22, 23 is designed for the variable adjustment of the drive pump 1 by a variable control pressure p28, p29 of hydraulic fluid HF. The at least one section 30, in particular the feed pressure section 30, of the hydraulic circuit 101 is designed to supply hydraulic pressure to the at least one actuator 22, 23 with hydraulic fluid HF at the set limit pressure p30, in particular the set feed limit pressure p30, for the control pressure p28, p29. The control unit 27 is designed to control the at least one actuator 22, 23 as a function of the at least one operating parameter BP in such a way that the at least one actuator 22, 23 uses the drive pump 1 to generate the variable drive flow with the variable drive pressure of hydraulic fluid HF in the at least one drive pressure section 31, 32 adjusted.

In particular, the control unit 27 has a hydraulic signal connection with the at least one actuator 22, 23.

In the exemplary embodiment shown, the hydraulic drive system 100 has two actuators 22, 23 based on hydraulic pressure.

In detail, the drive pump 1 is an axial piston pump with a variably adjustable swash plate. The at least one actuator 22, 23 is designed for variable adjustment of the swash plate.

In addition, the hydraulic drive system 100 has at least one drive cylinder 7, 8 and an associated drive piston 97, 98. The drive pump 1 is designed to move the at least one drive piston 97, 98 by generating the drive flow of hydraulic fluid HF.

In the exemplary embodiment shown, the hydraulic drive system 100 has at least two, in particular exactly two, drive cylinders 7, 8 and associated drive pistons 97, 98 in each case.

In addition, the hydraulic drive system 100 has a swing line 19 for hydraulic fluid HF. The drive pump 1 and the two drive cylinders 7, 8 form a closed drive circuit for hydraulic fluid HF by means of the swing line 19. The two drive pistons 97, 98 are coupled by means of the swing line 19, in particular in phase opposition.

In detail, the two drive cylinders 7, 8 are connected by means of the swing line 19.

In addition, the hydraulic drive system 100 has two pump lines 17, 18 for hydraulic fluid HF. The drive pump 1 and the drive cylinder 7 are connected by means of the pump line 17 . The drive pump 1 and the drive cylinder 8 are connected by means of the pump line 18 .

In detail, the drive pump 1 and the two drive cylinders 7, 8 form the closed drive circuit for hydraulic fluid HF by means of the swing line 19 and the two pump lines 17, 18.

In the exemplary embodiment shown, the drive state is on, a drive flow that is particularly required is relatively high and a drive pressure that is particularly required is relatively high. The feed limit pressure p30 is therefore set to 32 bar, in particular constant. The low-limit pressure p31 is set to 30 bar, in particular constant.

The drive pump 1 or the closed drive circuit has a high-pressure side HD and a low-pressure side ND, which are cyclically interchanged when the hydraulic drive system 100 or the building material delivery unit 210 is in operation. The drive pressure or high pressure HD is higher than the low limit pressure p31 or low pressure ND.

In 1 the high pressure side HD is down and the low pressure side is up.

Hydraulic fluid HF with the drive pressure or high pressure HD flows from the drive pump 1 through the pump line 18 to the drive cylinder 8, as indicated by an arrow. The pump line 18 and the drive cylinder 8 form, in particular at least partially, the high-pressure section 32.

Thus, the drive piston 98 moves in 1 to the right as indicated by an arrow.

Hydraulic fluid HF, particularly at a swing pressure, flows from the power cylinder 8 through the swing line 19 to the power cylinder 7 as indicated by an arrow. The swing line 19 and the drive cylinder 7 form, in particular at least partially, a swing pressure section.

Thus, the drive piston 97 moves in 1 to the left as indicated by an arrow.

Hydraulic fluid HF with the low limit pressure p31 or low pressure ND flows from the drive cylinder 7 through the pump line 17 to the drive pump 1, as indicated by an arrow. The pump line 17 and the drive cylinder 7 form, in particular at least partially, the low-pressure section 31.

The feed pressure section 30 feeds the low pressure section 31, as indicated by the arrow, in particular by means of the feed check valve 3.

When the pistons 97, 98 have reached their end positions, the high-pressure side HD and the low-pressure side ND are swapped. Then the high-pressure side HD is up and the low-pressure side ND is down. Thus, the drive piston 98 moves to the left and the drive piston 97 moves to the right.

In alternative embodiments, the power state may be on, but power flow medium and power pressure medium. The feed limit pressure can then be lowered to, for example, 22 bar and, in particular, set to be constant, and the low limit pressure can be lowered to, for example, 20 bar and, in particular, set to be constant.

Further, in alternate embodiments, the power state may be off. The feed limit pressure can then be lowered to, for example, 12 bar and, in particular, set to be constant, and the low limit pressure can be lowered to, for example, 10 bar and, in particular, set to be constant.

Furthermore, the at least one pressure-limiting valve unit 6, 24 is designed to variably set the limit pressure p30, p31/32 by flushing hydraulic fluid HF out of the hydraulic circuit 101, in particular into the container 50. In alternative exemplary embodiments, the at least one pressure-limiting valve unit can be designed for variable adjustment of the limit pressure by flushing hydraulic fluid out of the hydraulic circuit, in particular through a filter and/or to the feed pump, in particular to a suction side of the feed pump.

In detail, the charge pressure limiting valve unit 24 is designed to variably adjust the charge limit pressure p30 by flushing hydraulic fluid HF out of the charge pressure section 30, as indicated by an arrow.

In 1 A portion of the hydraulic fluid HF flows out of the feed pressure section 30 into the low-pressure section 31 . Another part of the hydraulic fluid HF is flushed out of the charge pressure section 30 .

The low-pressure limiting valve unit 6 is designed to variably adjust the low-limit pressure p31/32 by flushing hydraulic fluid HF out of the low-pressure section 31, 32, as indicated by an arrow.

In alternative exemplary embodiments, the hydraulic drive system can have a throttle valve unit, in particular the throttle valve unit, in particular instead of the low-pressure limiting valve unit. The throttle valve unit can be designed to variably adjust a flow, in particular a flushing flow, of hydraulic fluid out of the low-pressure section. The control unit can be designed to, depending on the at least one operating parameter of the hydraulic drive system and / or Hydraulic fluid to control the throttle valve unit in such a way that the throttle valve unit can adjust the flow of hydraulic fluid from the low-pressure section.

In 1 A part of the hydraulic fluid HF flows from the low-pressure section 31 to the drive pump 1. Another part of the hydraulic fluid HF is flushed out of the low-pressure section 31.

In detail, the hydraulic drive system 100 has an alternating scavenging valve 5 . The low-pressure section 31, 32 and the low-pressure relief valve unit 6 are connected by means of the alternating scavenging valve 5 for a flow of hydraulic fluid HF. In other words: in 1 Hydraulic fluid HF flows from the low pressure section 31 through the shuttle scavenging valve 5 to the low pressure relief valve unit 6 as indicated by an arrow.

In particular, the hydraulic drive system 100 has two, in particular hydraulic, control lines 25, 26 for, in particular automatic, control of the alternating scavenging valve 5.

In detail, the hydraulic drive system 100 has two flushing lines 20, 21 for hydraulic fluid HF. The pump line 17 and the alternating flushing valve 5 are connected by means of the flushing line 21 . The pump line 18 and the alternating flushing valve 5 are connected by means of the flushing line 20 . In addition, the alternating scavenging valve 5 is designed to connect that scavenging line 20, 21 to the low-pressure limiting valve unit 6, in particular for a flow of hydraulic fluid HF from the respective scavenging line 20, 21 to the low-pressure limiting valve unit 6, which has a relatively lower pressure than the other scavenging line. in 1 the flushing line 21.

The hydraulic drive system 100 also has a cooler 60 . The cooler 60 is designed to cool hydraulic fluid HF. The at least one pressure-limiting valve unit 6, 24 is designed to variably adjust one, in particular the, cooling flow of hydraulic fluid HF via the cooler 60 by adjusting the limit pressure p30, p31/32. The control unit 27 is designed to actuate the pressure limiting valve unit 6, 24 as a function of the at least one operating parameter BP, in particular the temperature T, in such a way that the pressure limiting valve unit 6, 24 adjusts the cooling flow of hydraulic fluid HF via the cooler 60.

In alternative exemplary embodiments, the hydraulic drive system, in particular instead of the pressure-limiting valve unit 6, can have a throttle valve unit, in particular the throttle valve unit. The throttle valve unit can be designed for the variable adjustment of a cooling flow, in particular the cooling flow, of hydraulic fluid via the cooler. The control unit can be designed to control the throttle valve unit as a function of the at least one operating parameter, in particular the temperature, in such a way that the throttle valve unit can adjust the cooling flow of hydraulic fluid via the cooler.

In detail, the cooling flow is adjusted by a pressure difference between the feed limit pressure p30 and the low limit pressure p 31/32.

In the embodiment shown, the temperature T is medium. The pressure difference is therefore set to 2 bar, in particular constant. In alternative embodiments, the temperature can be relatively high. The pressure difference can then be increased to, for example, 3 bar and, in particular, set to be constant. In particular, the low limit pressure, in particular relative to the supply limit pressure, can be lowered and, in particular, set to be constant. Further, in alternate embodiments, the temperature may be relatively low. The pressure difference can then be lowered to, for example, 1 bar and, in particular, set to be constant. In particular, the low limit pressure, in particular relative to the feed limit pressure, can be increased and, in particular, set to be constant.

In the exemplary embodiment shown, the hydraulic drive system 100 is designed to flush the cooling flow out of the hydraulic circuit 101, in particular the low-pressure section 31, 32, via the cooler 60. In other words: the cooler 60 is arranged, in particular in the direction of flow, after or behind the low-pressure limiting valve unit 6 and in particular in front of the container 50 . In other words: hydraulic fluid HF flows from the low-pressure relief valve unit 6 over or through the cooler 60 to the container 50, as indicated by an arrow. In alternative exemplary embodiments, the hydraulic drive system can be used to flush the cooling flow out of the hydraulic circuit, in particular the low-pressure section, via the cooler, in particular through a filter, in particular the filter, and/or to the feed pump, in particular to one, in particular the, suction side of the feed pump. be trained. In other words: hydraulic fluid can flow from the low-pressure limiting valve unit via or through the cooler, and in particular one, in particular the filter, to the feed pump, in particular to one, in particular the, suction side of the feed pump. Additionally or alternatively, in alternative exemplary embodiments, Hydraulic drive system, in particular instead of the low-pressure relief valve unit, one, in particular, have the throttle valve unit.

In addition, the hydraulic drive system 100 has at least one measuring sensor 80 . Measuring sensor 80 is designed to measure at least one property of hydraulic drive system 100 and/or hydraulic fluid HF. The control unit 27 is designed to determine the at least one operating parameter BP as a function of the measured property.

In particular, the control unit 27 has an electrical signal connection with the measuring sensor 80 .

In the exemplary embodiment shown, the hydraulic drive system 100 has only a single measurement sensor 80 . In alternative exemplary embodiments, the hydraulic drive system can have at least two measuring sensors.

Furthermore, in the exemplary embodiment shown, measuring sensor 80 is designed to measure a temperature T of hydraulic fluid HF and thus of hydraulic drive system 100 . The control unit 27 is designed to determine the at least one operating parameter BP as a function of the measured temperature T.

In detail, the measuring sensor 80 is designed to measure the temperature T of hydraulic fluid HF in the low-pressure section 31, 32. In other words: the measuring sensor 80 is arranged, in particular in the direction of flow, in particular after the alternating scavenging valve 5 and before the low-pressure limiting valve unit 6 . In alternative exemplary embodiments, the measuring sensor can be arranged on or in the drive pump, in particular in the leakage oil of the drive pump.

In addition, the hydraulic drive system 100 has a drive motor 70 . The drive motor 70 is designed to drive the feed pump 2 and, in particular, the drive pump 1 as well.

Furthermore, the building material conveying unit 210 has at least one, in particular two, conveying cylinders 34, 35 and one, in particular two, associated conveying pistons 38, 39, in particular arranged in the conveying cylinders 34, 35, as in FIG 2 shown. In particular, the at least one delivery cylinder 34, 35 is designed for building material BS. The at least one delivery cylinder 34, 35 is designed to pressurize building material BS.

In addition, the hydraulic drive system 100 has at least one, in particular two, piston rods 95, 96. The at least one piston rod 95, 96 is designed to couple or transmit movement of the at least one drive piston 97, 98 to the at least one delivery piston 38, 39. In particular, the at least one piston rod 95, 96 is attached to the at least one drive piston 97, 98 and/or to the at least one delivery piston 38, 39.

In addition, the building material conveying unit 210 has a diverter system 99 .

As the exemplary embodiments shown and explained above make clear, the invention provides an advantageous hydraulic drive system for a building material pump and an advantageous building material pump having such a hydraulic drive system that has improved properties, in particular enabling savings in energy or power.

Claims (14)

1. A hydraulic drive system (100) for a construction material pump (200), the hydraulic drive system (100) having:

   - a hydraulic circuit (101) for hydraulic fluid (HF),

   - a feed pump (2) which is designed for feeding hydraulic fluid (HF) into the hydraulic circuit (101),
   characterised by

   - at least one controllable pressure limiting valve unit (6, 24) which is designed for variably setting a limit pressure (p30, p31/32) of hydraulic fluid (HF) of at least one section (30, 31, 32) of the hydraulic circuit (101) within a pressure range (pmin, pmax),

   - wherein the at least one pressure limiting valve unit (6, 24) has a controllable proportional pressure limiting valve which is designed for continuously setting the limit pressure (p30, p31/32) of hydraulic fluid (HF) of the at least one section (30, 31, 32) of the hydraulic circuit (101) within the pressure range (pmin, pmax), and

   - a control unit (27) which is designed to control the pressure limiting valve unit (6, 24) in a manner dependent on at least one operating parameter (BP) of the hydraulic drive system (100) and/or of hydraulic fluid (HF) such that the pressure limiting valve unit (6, 24) sets the limit pressure (p30, p31/32) of the section (30, 31, 32) of the hydraulic circuit (101),

   - wherein the control unit (27) is designed to control the proportional pressure limiting valve (6, 24) in a manner dependent on the at least one operating parameter (BP) such that the proportional pressure limiting valve sets the limit pressure (p30, p31/32) of the section (30, 31, 32) of the hydraulic circuit (101).
2. The hydraulic drive system (100) as claimed in claim 1, having:

   - a drive motor (70) which is designed for driving the feed pump (2).
3. The hydraulic drive system (100) as claimed in any of the preceding claims,

   - wherein the at least one operating parameter (BP) is a drive state, a drive flow, a drive pressure, a drive rotational speed, a cooling flow, a temperature (T) and/or a degree of contamination.
4. The hydraulic drive system (100) as claimed in any of the preceding claims,

   - wherein the pressure range extends from a minimum of 2.5 bar (pmin), in particular from a minimum of 5 bar, in particular from a minimum of 10 bar, in particular from a minimum of 15 bar, to a maximum of 40 bar (pmax), in particular to a maximum of 35 bar, in particular to a maximum of 30 bar, in particular to a maximum of 25 bar.
5. The hydraulic drive system (100) as claimed in any of the preceding claims,

   - wherein the at least one section of the hydraulic circuit (101) has a feed pressure section (30) for hydraulic fluid (HF), and

   - wherein the at least one pressure limiting valve unit has a controllable feed pressure limiting valve unit (24) which is designed for variably setting a feed limit pressure (p30) of hydraulic fluid (HF) of the feed pressure section (30) within the pressure range (pmin, pmax).
6. The hydraulic drive system (100) as claimed in any of the preceding claims, having:

   - a variably adjustable drive pump (1) which is designed for generating a variable drive flow with a variable drive pressure of hydraulic fluid (HF) in at least one drive pressure section (31, 32) of the hydraulic circuit (101), and

   - at least one hydraulic pressure-based actuator (22, 23) which is designed for variably adjusting the drive pump (1) by means of a variable actuating pressure (p28, p29) of hydraulic fluid (HF),

   - wherein the at least one section (30) of the hydraulic circuit (101) is designed for supplying hydraulic pressure to the at least one actuator (22, 23) with hydraulic fluid (HF) with the set limit pressure (p30) for the actuating pressure (p28, p29),

   - wherein the control unit (27) is designed to control the at least one actuator (22, 23) in a manner dependent on the at least one operating parameter (BP) such that the at least one actuator (22, 23) adjusts the drive pump (1) for the generation of the variable drive flow with the variable drive pressure of hydraulic fluid (HF) in the at least one drive pressure section (31, 32).
7. The hydraulic drive system (100) as claimed in claim 6,

   - wherein the drive pump (1) is an axial piston pump with variably adjustable swashplate,

   - wherein the at least one actuator (22, 23) is designed for variably adjusting the swashplate.
8. The hydraulic drive system (100) as claimed in claim 6 or 7, having:

   - at least one drive cylinder (7, 8) and an associated drive piston (97, 98),

   - wherein the drive pump (1) is designed for variably moving the at least one drive piston (97, 98) by generating the drive flow of hydraulic fluid (HF).
9. The hydraulic drive system (100) as claimed in claim 8, having:

   - at least two drive cylinders (7, 8) and respectively associated drive pistons (97, 98), and

   - an oscillation line (19) for hydraulic fluid (HF),

   - wherein the drive pump (1) and the two drive cylinders (7, 8) form, by means of the oscillation line (19), a closed drive circuit for hydraulic fluid (HF), and

   - wherein the two drive pistons (97, 98) are coupled by means of the oscillation line (19).
10. The hydraulic drive system (100) as claimed in any of the preceding claims,

    - wherein the at least one section of the hydraulic circuit (101) has at least one low pressure section (31, 32) for hydraulic fluid (HF), and

    - wherein the at least one pressure limiting valve unit has a controllable low pressure limiting valve unit (6) which is designed for variably setting a low limit pressure (p31/p32) of hydraulic fluid (HF) of the at least one low pressure section (31, 32) within the pressure range (pmin, pmax).
11. The hydraulic drive system (100) as claimed in any of the preceding claims, having:

    - a cooler (60) which is designed for cooling hydraulic fluid (HF),

    - wherein the at least one pressure limiting valve unit (6, 24) is designed for variably setting a cooling flow of hydraulic fluid (HF) via the cooler (60) by setting the limit pressure (p30, p31/32), and

    - wherein the control unit (27) is designed to control the pressure limiting valve unit (6, 24) in a manner dependent on the at least one operating parameter (BP) such that the pressure limiting valve unit (6, 24) sets the cooling flow of hydraulic fluid (HF) via the cooler (60).
12. The hydraulic drive system (100) as claimed in any of the preceding claims,

    - wherein the at least one pressure limiting valve unit (6, 24) is designed for variably setting the limit pressure (p30, p31/32) by purging hydraulic fluid (HF) out of the hydraulic circuit (101).
13. The hydraulic drive system (100) as claimed in any of the preceding claims, having:

    - at least one measuring sensor (80) which is designed for measuring at least one property, in particular a temperature (T) and/or a degree of contamination, of the hydraulic drive system (100) and/or of hydraulic fluid (HF),

    - wherein the control unit (27) is designed for determining the at least one operating parameter (BP) in a manner dependent on the measured property (T).
14. A construction material pump (200), having:

    - a construction material conveying unit (210) which is designed for conveying construction material (BS),

    - a hydraulic drive system (100) as claimed in any of the preceding claims which is designed for driving the construction material conveying unit (210).

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