Hydrostatic hybrid drive unit for a hybrid powertrain

Abstract

Hydrostatic hybrid drive device (H) for a hybrid drive train (A), in particular of a vehicle, with a drive motor (AM) and a consumer (V) driven by the drive motor (AM), characterized in that the hybrid drive device (H) comprises only a hydrostatic displacement machine (1) which is operated in an open circuit and can be operated as a pump and motor with the same direction of rotation and the same flow direction of a pressure medium, wherein the displacement machine (1) is designed as a variable displacement drive with unilateral adjustability in the displacement volume and a displacement volume adjusting device (1a) of the variable displacement drive is adjustable from a position with minimum displacement volume in one adjusting direction, wherein a delivery line (2) is connected to an outlet-side delivery side (F) of the displacement machine (1), which leads to a high-pressure storage device (3),wherein the positive displacement machine (1) in pumping mode delivers exclusively to the high-pressure storage device (3), which is the only consumer supplied by the positive displacement machine (1), and a shut-off valve (5) opening towards the high-pressure storage device (3) is arranged in the delivery line (2), wherein a branch line (6) branches off from the delivery line (2) between the delivery side (F) of the positive displacement machine (1) and the shut-off valve (5), which is connected to a low-pressure storage device (7), and a suction line (8) connected to the low-pressure storage device (7) is connected to an inlet-side suction side (S) of the positive displacement machine (1),wherein a shut-off valve (9) blocking towards the low-pressure storage device (7) is arranged in the intake line (8) and a discharge line (10) is connected from the high-pressure storage device (3) to the intake line (8) between the suction side (S) of the positive displacement machine (1) and the shut-off valve (9), wherein a valve assembly (15) is provided which controls the discharge line (10) and the branch line (6), wherein the valve assembly (15) shuts off the discharge line (10) and the branch line (6) during pump operation of the positive displacement machine (1) and controls the discharge line (10) and the branch line (6) to allow flow during motor operation of the positive displacement machine (1).

Description

[0001] The invention relates to a hydrostatic hybrid drive device for a hybrid drive train, in particular of a vehicle, comprising a drive motor and a consumer driven by the drive motor.

[0002] Vehicles, for example motor vehicles or public transport vehicles, for example buses, preferably for local public transport, as well as mobile self-propelled work machines, in particular industrial trucks, agricultural machinery, forestry machinery and construction machinery, for example excavators, wheel loaders and telescopic loaders, tractors, combine harvesters, forage harvesters, sugar beet or potato harvesters, have a drive train with a drive motor, usually designed as an internal combustion engine, which drives a consumer, for example a drive system, of the vehicle.

[0003] Hybrid powertrain concepts are increasingly being used in such vehicles. Regarding the design of the hybrid powertrain, versions such as series hybrid, parallel hybrid, or power-split hybrid are known.

[0004] Vehicles with a hybrid powertrain are powered by a combination of different energy sources. In addition to the drive motor, which is usually an internal combustion engine, the energy source for the hybrid drive system is also provided and carried in the vehicle. In a mechanical hybrid drive system, this can be, for example, a flywheel; in an electric hybrid drive system, a battery, accumulators, or high-performance capacitors; and in a hydrostatic hybrid drive system, a hydraulic accumulator.

[0005] Known hybrid drive systems exhibit high system complexity and therefore high construction costs.

[0006] Common electric hybrid drive systems consist of an electrical energy storage device and an electric machine that can operate as both a motor and a generator. This machine is typically an asynchronous motor and requires power electronics for its control. The electrical energy storage device also usually requires an air conditioning system to heat or cool it during operation. Due to the low capacity of the electrical energy storage devices and the additional power electronics and air conditioning components required for operation, electric hybrid drive systems are very expensive. Furthermore, the low power and energy density of the electrical energy storage devices negatively impacts the overall weight of the vehicle.Another disadvantage of electric hybrid drive systems is that the electrical energy storage system poses an increased risk, for example through self-ignition and endangering the person extinguishing a burning vehicle with a built-in electrical energy storage system of an electric hybrid drive system.

[0007] Known mechanical hybrid drive systems with a mechanical energy storage device, such as a flywheel energy storage system, typically operate with very large or very fast-rotating flywheels. However, the additional mass of the flywheel energy storage system in a mechanical hybrid drive system reduces the vehicle's energy consumption advantage, as correspondingly more energy is required for acceleration during driving cycles.

[0008] Known hydrostatic hybrid drive systems often require a large number of valves to store and release power in a hydraulic accumulator. WO 2007 / 071362 A1 discloses a generic hydrostatic hybrid drive system for a vehicle, in which the hydrostatic hybrid drive system is designed as a positive displacement machine. One side is connected to a reservoir via a line, and the other side is connected to a hydraulic accumulator via another line. The positive displacement machine can be operated as both a pump and a motor and is designed to pump hydraulic fluid in both flow directions. The positive displacement machine is designed as a variable displacement drive with adjustable displacement volume. In WO 2007 / 071362 A1, the flow directions of the positive displacement machine differ between pump and motor operation.In order to enable pump and motor operation with the same direction of rotation of the displacement machine, the adjustment drive must be designed as being adjustable on both sides and thus adjustable in both directions via the position with zero displacement volume, which makes the adjustment device of the displacement machine and thus the displacement machine of the hydrostatic hybrid drive system correspondingly complex.

[0009] A hydraulic multi-stage transmission system with brake energy storage is known from DE 28 17 405 A1.

[0010] DE 10 2011 107 061 A1 is a drive train of a vehicle with a hydraulic pressure accumulator.

[0011] DE 10 2005 010 092 B4 discloses a hydrostatic continuously variable transmission.

[0012] US 2012 / 0273076A1 discloses a hydraulic pressure accumulator of a hybrid hydraulic drive system of a vehicle.

[0013] DE 601 18 987 T2 discloses hydraulic energy storage systems of a vehicle that can store kinetic energy during braking.

[0014] US Patent 2007 / 0022749A1 discloses a hydraulic drive system with a pump-motor unit which, in pump mode, charges a high-pressure accumulator with hydraulic fluid and, in motor mode, is driven by the hydraulic fluid from the high-pressure accumulator.

[0015] The present invention is based on the objective of providing a hydrostatic hybrid drive device that has a simple, compact and cost-effective design.

[0016] This problem is solved according to the invention in that the hybrid drive device comprises only a hydrostatic displacement machine which is operated in an open circuit and can be operated as a pump and motor with the same direction of rotation and the same flow direction of a pressure medium, wherein the displacement machine is designed as an adjustable drive unit adjustable in one direction within the displacement volume and a displacement volume adjusting device of the drive unit is adjustable in one direction starting from a position with minimum displacement volume, wherein a delivery line is connected to an outlet-side delivery side of the displacement machine, which leads to a high-pressure storage device, wherein in pump mode the displacement machine delivers exclusively to the high-pressure storage device, which is the only consumer supplied by the displacement machine.and a shut-off valve opening towards the high-pressure storage device is arranged in the delivery line, wherein a branch line branches off from the delivery line between the delivery side of the positive displacement machine and the shut-off valve, which is connected to a low-pressure storage device, and an intake line connected to the low-pressure storage device is connected to an inlet-side suction side of the positive displacement machine, wherein a shut-off valve opening towards the low-pressure storage device is arranged in the intake line, and a discharge line is connected from the high-pressure storage device to the intake line between the suction side of the positive displacement machine and the shut-off valve, wherein a valve assembly is provided which controls the discharge line and the branch line.wherein the valve device shuts off the discharge line and the branch line during pump operation of the positive displacement machine and controls the discharge line and the branch line to allow flow during motor operation of the positive displacement machine.

[0017] The hydrostatic hybrid drive device according to the invention consists of a hydrostatic positive displacement machine operated in an open circuit, which can be operated as both a pump and a motor with the same direction of rotation and flow direction of a hydraulic fluid. The positive displacement machine is connected at its outlet-side delivery end to a delivery line leading to the high-pressure storage device. The high-pressure storage device is the sole consumer of the positive displacement machine, so that in the hybrid drive device according to the invention, the positive displacement machine delivers exclusively to the high-pressure storage device. A shut-off valve, opening towards the high-pressure storage device, is arranged in the delivery line and prevents backflow from the high-pressure storage device to the delivery end of the positive displacement machine.With such a shut-off valve, the charging operation of the high-pressure accumulator can be carried out in a simple circuit-related manner, and when the high-pressure accumulator is charged, the flow of the hydraulic fluid from the accumulator to the delivery side of the positive displacement machine is prevented. A suction line, connected to the low-pressure accumulator, is connected to an inlet side of the positive displacement machine. A shut-off valve, blocking flow towards the low-pressure accumulator, is located in this suction line. A discharge line of the high-pressure accumulator is connected to the suction line between the suction side of the positive displacement machine and the shut-off valve.During engine operation of the positive displacement machine, pressurized hydraulic fluid is supplied to the suction side of the machine from the high-pressure accumulator. A simple shut-off valve located in the suction line prevents the hydraulic fluid from flowing from the high-pressure accumulator into the low-pressure accumulator during engine operation. Such a positive displacement machine has a simple and cost-effective design. A branch line extends from the delivery line between the delivery side of the positive displacement machine and the shut-off valve located in the delivery line; this branch line is connected to the low-pressure accumulator.With such a branch line, it can be achieved in a simple circuit design that, during motor operation of the positive displacement machine, in which the machine is driven on the suction side by the pressure medium from the high-pressure accumulator, the delivery side of the positive displacement machine is connected to the low-pressure accumulator via the branch line, thus enabling a return flow of the pressure medium driving the positive displacement machine from the high-pressure accumulator to the low-pressure accumulator. To control the pump and motor operation of the positive displacement machine, a valve assembly is provided that controls the discharge line and the branch line. During pump operation of the positive displacement machine, the valve assembly shuts off the discharge line and the branch line, and during motor operation of the positive displacement machine, it opens the discharge line and the branch line to allow flow.With the valve assembly, which controls the branch line and the discharge line, it is thus easily achieved that the positive displacement machine, in pump mode (with the discharge line and the branch line closed off by means of the valve assembly), draws pressure medium from the low-pressure accumulator on the suction side and delivers it to the high-pressure accumulator on the delivery side. Conversely, in motor mode (with the discharge line and the branch line opened by means of the valve assembly), the positive displacement machine is driven on the suction side by the pressurized pressure medium from the high-pressure accumulator and delivers it to the low-pressure accumulator on the delivery side via the open branch line. Since, in the hybrid drive system according to the invention, the high-pressure accumulator is the only consumer of the positive displacement machine, a compact design of the hybrid drive system can be achieved.Furthermore, this results in lower construction costs for the valve assembly. Overall, the hybrid drive unit according to the invention has a simple and cost-effective design for the positive displacement machine, a simple circuit design and compact construction due to the single consumer of the positive displacement machine formed by the high-pressure storage device, and a simple design for the valve assembly for controlling the pump and motor operation, so that the hybrid drive unit according to the invention has a simple, compact, and cost-effective design.

[0018] According to the invention, the positive displacement machine is designed as a variable displacement drive that is adjustable in one direction within the displacement volume. Due to the constant flow direction of the pressure medium in the positive displacement machine during both pump and motor operation, a positive displacement machine designed as a variable displacement drive offers particular advantages in terms of a simple and cost-effective design, since the positive displacement machine can be implemented as a variable displacement drive in which a displacement volume adjustment device of the variable displacement drive can be adjusted in a single direction starting from a position with a minimum displacement volume, for example, a position with zero displacement volume.Such a unilaterally adjustable adjustment drive has a significantly simplified design for the adjustment of the displacement volume control device compared to a unilaterally adjustable adjustment drive, resulting in a cost-effective and compact design of the displacement machine.

[0019] According to an advantageous embodiment of the invention, the valve assembly is designed as a two-position four-port valve to which the branch line and the discharge line are connected, wherein the two-position four-port valve has a closed position in which the branch line and the discharge line are shut off, and a flow position in which the branch line and the discharge line are open. Such a two-position four-port valve has a simple design and makes it easy to control the pump operation and the motor operation of the positive displacement machine.

[0020] The construction effort can be further reduced if the two-position four-port valve is designed as a switching valve.

[0021] According to an alternative embodiment of the invention, the valve assembly comprises a first control valve that controls the discharge line and a second control valve that controls the branch line. The valve assembly is thus designed in a modular fashion and includes two simple control valves that control the discharge line and the branch line, respectively. Such a valve assembly consisting of two separate control valves also requires minimal effort.

[0022] According to an advantageous embodiment of the invention, the first control valve and / or the second control valve is designed as a two-position, two-port valve, having a closed position and a flow position. A valve assembly consisting of two two-position, two-port valves has a simple design and makes it easy to control the pump operation and the motor operation of the positive displacement machine.

[0023] The construction effort can be further reduced if the first control valve and / or the second control valve is designed as a switching valve.

[0024] According to an alternative and equally advantageous embodiment of the invention, the first control valve and / or the second control valve is designed as a pressure relief valve, in particular a pressure limiting valve, with adjustable opening pressure. With a pressure relief valve, for example a pressure limiting valve, arranged in the discharge line or branch line and with adjustable opening pressure, the pump operation and the motor operation of the positive displacement machine can be controlled with minimal construction effort for the valve assembly by closing or opening the discharge line or branch line.

[0025] According to an advantageous embodiment of the invention, the valve device is electrically actuated and is connected for actuation to an electronic control device which is connected on the input side to a sensor device that detects the storage pressure of the high-pressure storage device.This results in a simple control system, since with an electronic control unit and an electrically actuated valve unit, the pump operation of the displacement machine to charge the high-pressure storage device can be initiated by appropriate control of the valve unit, depending on the storage pressure of the high-pressure storage device detected by the sensor unit, and the motor operation of the displacement machine can be initiated to deliver torque when a corresponding storage charging pressure is present in the high-pressure storage device.

[0026] The electronic control unit advantageously incorporates operating strategies to charge the high-pressure energy storage device, depending on the vehicle's operating conditions, using excess energy from the drive motor and / or during braking by the positive displacement pump. This allows the high-pressure energy storage device to be charged in specific operating conditions where excess energy is generated by the drive motor and / or during braking with the energy generated by the consumer, thus enabling energy recuperation. The electronic control unit communicates with corresponding actuating elements that determine the respective operating condition and / or braking activity of the consumer, such as an accelerator pedal or a brake pedal when the consumer is used as the vehicle's drive system.

[0027] In the hybrid drive system according to the invention, the displacement machine can serve as a booster drive for the running drive motor and / or as a hydraulic starter for the switched-off drive motor during motor operation. The hybrid drive system according to the invention can thus be used to support the running drive motor and / or as a hydraulic starter within the framework of a start-stop function of the drive motor, whereby a cost-effective start-stop function of the drive motor can be achieved due to the robust design and function of the displacement machine.

[0028] According to an advantageous embodiment of the invention, a pressure relief valve is associated with the high-pressure storage device. During pump operation of the positive displacement machine, in which the high-pressure storage device is charged with hydraulic fluid, the charging operation can be easily secured and the storage pressure present in the high-pressure storage device protected by a pressure relief valve.

[0029] According to a preferred embodiment of the invention, the high-pressure storage device can be designed as a pressure accumulator, in particular a bladder accumulator, piston accumulator, or diaphragm accumulator. Preferably, the high-pressure storage device is subject to a preload, for example, a gas preload.

[0030] According to one embodiment of the invention, the low-pressure storage device can be designed as a container, in particular a non-prestressed container, or according to an alternative embodiment of the invention as a pressure accumulator, in particular a prestressed container, bladder accumulator, piston accumulator, or diaphragm accumulator. The non-prestressed container is preferably in contact with the environment and thus the atmosphere. A pressure accumulator designed as a prestressed container, as a low-pressure storage device, is preferably prestressed, for example by a gas prestress or pneumatically prestressed, the prestress preferably being set to a low pressure level in the range of 2 to 10 bar.

[0031] With regard to the simple design and compact construction of the hybrid drive system according to the invention, particular advantages arise when, according to one embodiment of the invention, the high-pressure storage device and the low-pressure storage device are designed as double-piston accumulators, wherein a first pressure chamber of the double-piston accumulator is connected to the delivery line and the discharge line, and a second pressure chamber of the double-piston accumulator is connected to the branch line and the suction line. With a double-piston accumulator, the function of the high-pressure storage device and the tank-side low-pressure storage device can be achieved with a particularly small installation space requirement.

[0032] The displacement volume control device of the variable displacement drive is advantageously connected to the electronic control unit for control purposes. The electronic control unit can thus control the torque of the displacement machine by appropriately adjusting the displacement volume control device and therefore the displacement volume of the variable displacement drive. This torque, in conjunction with the storage pressure present in the high-pressure accumulator, is absorbed by the displacement machine during pump operation and delivered by the displacement machine during motor operation.

[0033] Particular advantages arise when a retarder valve is installed in the delivery line. With a retarder valve located in the delivery line leading to the high-pressure accumulator, and thus in the inlet of the high-pressure accumulator, the pressure can be easily increased on the delivery side of the positive displacement machine if the accumulator charging pressure is insufficient, and a pressure on the delivery side of the positive displacement machine can be set according to the desired braking performance.

[0034] Furthermore, a vehicle is provided with a drive train driven by a drive motor and a hydrostatic hybrid drive system according to the invention, wherein the drive train is designed as a parallel hybrid. With the hydrostatic hybrid drive system according to the invention, a parallel hybrid can be created in a vehicle in a simple and cost-effective manner, requiring little installation space for the hybrid drive system, in which the displacement engine and the drive motor act on the drive train.

[0035] The consumer can be designed as a rotary drive unit driven by a gearbox. With a hybrid drive device according to the invention, energy recovery can occur during braking of the rotary drive unit in a vehicle with a rotary drive unit, for example, a construction machine designed as an excavator, and support for the drive motor can be achieved when accelerating the rotary drive unit.

[0036] The consumer can be configured as a drive axle driven by a transmission with at least two driven drive wheels. With a hybrid drive system according to the invention, energy recovery can occur during braking in a vehicle with a drive system comprising a drive axle, for example, a motor vehicle or a bus, and support for the drive motor can be achieved during acceleration of the vehicle.

[0037] Due to the compact dimensions and design of the hybrid drive unit according to the invention, the hybrid drive unit can be arranged in the drive train in a direct through-drive configuration. The displacement machine of the hybrid drive unit is thus directly installed and integrated into the drive train, enabling a through-drive configuration.

[0038] Alternatively, the hybrid drive unit can be connected to the drivetrain via a displacement transmission, in particular a spur gear transmission. The displacement machine of the hybrid drive unit is thus connected to and integrated into the drivetrain via a displacement transmission.

[0039] Such a connection of the hybrid drive unit to the vehicle's drivetrain via a transfer case allows the hybrid drive unit to be connected to and disconnected from the drivetrain using a clutch. In the open position of the clutch, the displacement machine of the hybrid drive unit can be temporarily disconnected from the drivetrain, thus preventing continuous and inefficient operation of the displacement machine in certain operating conditions, such as during extended periods of stationary driving.

[0040] Due to the compact dimensions and compact design of the hybrid drive unit according to the invention, the hybrid drive unit can be installed at any point in the drive train.

[0041] The hybrid drive unit is located in the drivetrain between the drive motor and a transmission that drives the consumer.

[0042] A particular advantage here is the arrangement of a clutch device in the power flow between the hybrid drive unit and the transmission within the drivetrain. With the clutch device open, the hybrid drive unit according to the invention can easily start the switched-off drive motor as part of a start-stop function.

[0043] A particular advantage here is the arrangement of a coupling device in the power flow between the drive motor and the hybrid drive unit within the drivetrain. If this coupling device is open and a coupling device in the power flow between the hybrid drive unit and the transmission is closed, the consumer can be driven via the hybrid drive unit even when the drive motor is switched off.

[0044] According to an alternative design, the hybrid drive unit is arranged in the drivetrain between the transmission and the consumer.

[0045] A particular advantage here is the arrangement of a clutch device in the power flow between the transmission and the hybrid drive unit within the drivetrain. With the clutch device open, the consumer can be driven via the hybrid drive unit even when the main engine is switched off.

[0046] According to an alternative design, the hybrid drive system is connected to an additional axle of the vehicle. If the vehicle has an additional axle, besides the drive axle driven via the transmission, which is connected to the hybrid drive system, energy can be recuperated during braking and additional torque can be applied by the hybrid drive system via the additional axle during driving.

[0047] A particularly advantageous feature here is the integration of a coupling device in the power flow between the hybrid drive unit and the auxiliary axle. This coupling device allows the displacement motor of the hybrid drive unit to be easily disconnected from the auxiliary axle. With the coupling device in the open position, the displacement motor of the hybrid drive unit can be temporarily disconnected from the auxiliary axle, thus preventing continuous and inefficient operation of the displacement motor in certain operating conditions, such as during extended periods of stationary driving.

[0048] Furthermore, according to one embodiment, the hybrid drive unit can be driven by a power take-off (PTO) of the drive motor. By connecting the displacement machine of the hybrid drive unit to a PTO of the drive motor, a booster drive to support the running drive motor and / or a hydraulic starter for starting the switched-off drive motor within the framework of a start-stop function can also be created via the displacement machine. A coupling device can also be provided for this purpose, with which the

[0049] The displacement machine can be separated from the auxiliary drive to avoid losses from the continuous operation of the displacement machine.

[0050] Further advantages and details of the invention are explained in more detail with reference to the exemplary embodiments shown in the schematic figures. Here, Fig. 1 the circuit diagram of a first embodiment of a hydrostatic hybrid drive device according to the invention, Fig. 2 the circuit diagram of a second embodiment of a hydrostatic hybrid drive device according to the invention, Fig. 3 the circuit diagram of a third embodiment of a hydrostatic hybrid drive device according to the invention, Fig. 4 an embodiment of the Fig. 1 with an alternative embodiment of a valve device of the hybrid drive device, Fig. 5 an embodiment of the Fig. 1 with an alternative embodiment of a valve device of the hybrid drive device and Fig. 6a to 6e different embodiments of a vehicle with a powertrain comprising a hybrid drive system according to the invention.

[0051] In the Fig. Figures 1 to 5 show different embodiments of a hydrostatic hybrid drive device H according to the invention. Fig. Parts 1 to 5 are identical components with the same reference numbers.

[0052] The hybrid drive device H according to the invention consists of a single hydrostatic displacement machine 1, which is operated in an open circuit and can be operated as both a pump and a motor with the same direction of rotation and flow direction of a pressure medium. In the hybrid drive device H according to the invention, the displacement machine is designed as a simple two-quadrant drive unit, which can be operated as both a pump and a motor with the same direction of rotation and flow direction of the pressure medium.

[0053] The positive displacement pump 1 has an outlet-side delivery port F to which a delivery line 2 is connected, leading to a high-pressure storage device 3. The high-pressure storage device 3 is the sole consumer of the positive displacement pump 1, so that in pumping mode, the positive displacement pump 1 delivers only hydraulic fluid to the high-pressure storage device 3. A check valve 5, opening towards the high-pressure storage device 3, is arranged in the delivery line 3. In the illustrated embodiment, the check valve 5 is designed as a non-return valve. No other valve is arranged in the delivery line 2, which leads from the delivery port F of the positive displacement pump 1 to the high-pressure storage device 3, besides the check valve 5.

[0054] From the conveying line 2, between the conveying side F of the displacement machine 1 and the shut-off valve 5, and thus upstream of the shut-off valve 5, a branch line 6 branches off, which is connected to a low-pressure storage device 7.

[0055] A suction line 8, connected to the low-pressure storage device 7, is connected to an inlet-side suction side S of the positive displacement machine 1. A shut-off valve 9, which blocks flow towards the low-pressure storage device 7, is arranged in this line. In the illustrated embodiment, the shut-off valve 9 is designed as a check valve.

[0056] A discharge line 10 is connected to the suction line 8 between the suction side S of the displacement machine 1 and the shut-off valve 9 and thus downstream of the shut-off valve 9, and is connected to the high-pressure storage device 3.

[0057] The displacement machine 1 has a drive shaft 11, via which, in pump operation of the displacement machine 1, a torque from a drive train can be applied to drive the displacement machine 1, or via which, in motor operation of the displacement machine 1, a torque can be introduced from the displacement machine 1 into a drive train.

[0058] The hybrid drive device H according to the invention further comprises a valve device 15 which controls the discharge line 10 and the branch line 6.

[0059] In pumping mode of the positive displacement machine 1, the discharge line 10 and the branch line 6 are shut off by means of the valve device 15, so that in pumping mode the positive displacement machine 1 draws in pressure medium with one suction side S via the suction line 8 and the opening shut-off valve 9 and conveys this on the conveying ropes F via the conveying line 2 and the opening shut-off valve 5 into the high pressure storage device 3 and charges it with pressure medium.

[0060] During engine operation of the positive displacement machine 1, the discharge line 10 and the branch line 6 are opened to allow flow by means of the valve assembly 15. Thus, during engine operation, the positive displacement machine 1 is driven by pressurized hydraulic fluid from the high-pressure accumulator 3, supplied via the suction side S, which is connected to the high-pressure accumulator 3 via the open discharge line 10. During engine operation, the delivery side F of the positive displacement machine 1 is connected to the low-pressure accumulator 7 via the open branch line 6, so that a return flow of the hydraulic fluid driving the positive displacement machine 1 from the high-pressure accumulator 3 is achieved via the delivery line 2 and the open branch line 6 to the low-pressure accumulator 7.During operation of the positive displacement machine 1, the shut-off valve 5 in the delivery line 2, which blocks in the direction of the delivery side F, prevents the return of the hydraulic fluid from the high-pressure accumulator 3 to the delivery side F of the positive displacement machine 1. During operation of the positive displacement machine 1, the shut-off valve 9 in the suction line 8, which blocks in the direction of the low-pressure accumulator 7, prevents the hydraulic fluid from flowing from the high-pressure accumulator 3 into the low-pressure accumulator 7 when the discharge line 10 is open.

[0061] The high-pressure storage device 3 is further equipped with a pressure limiting valve 16, which protects the storage charging pressure.

[0062] In the Fig. 1, Fig. 2, Fig. 4 and Fig. 5 The high-pressure storage device 3 is designed as a pressure accumulator 3a, in particular a bladder accumulator, piston accumulator or diaphragm accumulator. The pressure accumulator 3a is under a preload, for example a gas preload.

[0063] The low-pressure storage device 7 of the Fig. 1, Fig. 4 and Fig. 5 is designed as container 7a. Container 7a of the Fig. 1, Fig. 4 and Fig. 5 is designed as a non-prestressed container that is in contact with the environment and thus with the atmosphere.

[0064] A sensor device 17 is provided to detect the storage charging pressure present in the high-pressure storage device 3, which is connected to an electronic control device 18.

[0065] The valve assembly 15 is electrically actuated and is connected to the electronic control unit 18 for actuation.

[0066] In the Fig. In sections 1 to 5, the displacement machine 1 is designed as an adjustable displacement drive. The displacement machine is adjustable in one direction, wherein a displacement volume adjusting device 1a of the displacement machine 1, for example, an inclination-adjustable swashplate in the case of the displacement machine as an axial piston machine in swashplate construction, is adjustable from a position with minimum displacement volume, preferably a position with zero displacement volume, in an adjusting direction towards a maximum displacement volume.

[0067] The displacement machine 1 is electrically or electro-hydraulically, in particular electro-proportionally, controllable in its displacement volume. For this purpose, the displacement volume control device 1a of the displacement machine 1 can be electrically controlled or actuated by means of an electrical actuating device 1b, which is connected to the electronic control unit 18 for control purposes. Alternatively, the displacement machine 1 can be hydraulically controlled in its displacement volume.

[0068] In the Fig. 1 to 3, the electrically actuated valve assembly 15 is designed as a two-position four-port valve 20, to which the branch line 6 and the discharge line 10 are connected. The two-position four-port valve 20 arranged in the branch line 6 and the discharge line 10 has a closed position 20a, in which the branch line 6 and the discharge line 10 are closed, and a flow position 20b, in which the branch line 6 and the discharge line 10 are open.

[0069] The two-position four-port valve 20 is in the illustrated embodiments of the Fig. 1 to 3 designed as a switching valve.

[0070] In the illustrated embodiments, the two-position four-port valve 20 is actuated into the closed position 20a by means of a spring device 21 and can be actuated into the flow position 20b by means of an electrical actuating device 22, for example a switching magnet, which is connected to the electronic control device 18 for actuation.

[0071] In the Fig. Figure 2 shows an embodiment of the invention in which the low-pressure storage device 7 is designed as a pressure accumulator 7b. In the illustrated embodiment, the pressure accumulator 7b is designed as a pre-pressurized container, for example, as a pneumatically pre-pressurized container. Alternatively, the pressure accumulator 7b can be designed as a bladder accumulator, piston accumulator, or diaphragm accumulator. The pre-pressurization of the pressure accumulator 7b is preferably set to a low pressure level in the range of 2 to 10 bar, which is lower than the pre-pressurization of the pressure accumulator 3a. The suction line 8 and the branch line 6 are connected to the pressure accumulator 7b.

[0072] In the Fig. Figure 2 shows a leakage oil line 1c of the positive displacement machine 1, which is connected to the low-pressure storage device 7. Leakage oil accumulating within the housing of the positive displacement machine 1 during operation can thus be discharged into the low-pressure storage device 7.

[0073] In the Fig. Figure 3 shows an embodiment of the invention in which the function of the high-pressure storage device 3 and the low-pressure storage device 7 is formed by a double piston storage device 30.

[0074] The double-piston accumulator 30 has a housing 31 in which two pistons 32, 33 are arranged to be longitudinally displaceable. The two pistons 32, 33 are rigidly connected to each other via a connecting element 34, for example, a piston rod. Between the two pistons 32, 33, the housing 31 is provided with a partition 35 through which the connecting element 34 passes. The connecting element 34 is sealed in the partition 35 in a manner not shown in detail. The inner end faces of the two pistons 32, 33, together with the housing 30 and the partition 35, each define pressure chambers 36, 37. The pressure chambers 36, 37 surround the connecting element 34 and are thus designed as piston-rod-side pressure chambers. The outer end face of the piston 32, together with the housing 30, defines a pressure chamber 38, which is vented. The outer face of the piston 33, together with the housing 30 and a housing cover, defines a pressure chamber 39 which is under a preload.In the illustrated embodiment, a gas preload is provided, for example N2.

[0075] The inner end faces and the outer end face of the two pistons 32, 33 each have the same area.

[0076] In the illustrated embodiment, the pressure chamber 36 of the double-piston accumulator 30 forms the high-pressure storage device 3, for which purpose the pressure chamber 36 of the double-piston accumulator 30 is connected to the delivery line 2 and the discharge line 10. The pressure chamber 37 of the double-piston accumulator 30 forms the low-pressure storage device 7, for which purpose the pressure chamber 37 of the double-piston accumulator 30 is connected to the branch line 6 and the suction line 8.

[0077] It is understood that the double-piston accumulator 30 can also receive and release the pressure medium at the two external pressure chambers 39 and 38. For this purpose, for example, pressure chamber 36 is pre-pressurized, and the high-pressure accumulator 3 is formed by pressure chamber 39, which is connected to the delivery line 2 and the discharge line 10. Pressure chamber 38 is to be closed by means of a housing cover, so that pressure chamber 38 can be configured as a low-pressure accumulator 7, which is connected to the branch line 6 and the suction line 8. Pressure chamber 37 is then to be vented.

[0078] To compensate for the leakage oil of the displacement machine 1, the following is necessary: Fig. 3. An expansion tank 40 is provided, which is connected to the suction line 8. The check valve 9 is arranged between the connection 41 of the expansion tank 40 to the suction line 8 and the suction side S of the positive displacement machine 1. In the illustrated embodiment, the expansion tank 40 is designed as a pre-pressurized tank, for example, as a pneumatically pre-pressurized tank. Alternatively, the expansion tank 40 can be designed as a bladder accumulator, piston accumulator, or diaphragm accumulator.

[0079] In the Fig. In the delivery line 2, which runs from the delivery side F of the displacement machine 1 to the high-pressure accumulator 3, a retarder valve 70 is arranged. In the illustrated embodiment, the retarder valve 70 is designed as an electrically adjustable pressure valve, which is connected to the electronic control unit 18 for control. The retarder valve 70 makes it possible to adjust the pressure in the inlet of the high-pressure accumulator 3 according to the desired braking performance if there is not yet sufficient boost pressure in the high-pressure accumulator 3.

[0080] In the Fig. 4 and Fig. Figure 5 shows alternative versions of the valve assembly 15 in a sectional design.

[0081] In the Fig. 4 and Fig. 5 the valve assembly 15 has a first control valve 50 that controls the discharge line 10, and a second control valve 55 that controls the branch line 6.

[0082] The first control valve 50 is designed as a two-position, two-port valve 51, which is arranged in the discharge line 10 and has a closed position 50a and a flow position 50b. The closed position 50a is preferably leak-tight with a shut-off valve 50c, for example a check valve, which is effective in the shut-off control and blocks in the direction of the suction line 8. In the illustrated embodiment, the two-position, two-port valve 51 is actuated into the closed position 50a by means of a spring device 52 and can be actuated into the flow position 50b by means of an electrical actuating device 53, for example a switching solenoid, which is connected to the electronic control unit 18 for actuation.

[0083] The two-position, two-port valve 51 is designed as a switching valve in the illustrated embodiment.

[0084] In the Fig. 4 The second control valve 55 is also designed as a two-position, two-port valve 56, which is arranged in the branch line 6 and has a closed position 55a and a flow position 55b. The closed position 55a is preferably leak-tight with a shut-off valve 55c, for example a check valve, which is effective in the shut-off control and blocks in the direction of the low-pressure storage device 7. In the illustrated embodiment, the two-position, two-port valve 56 is actuated into the closed position 55a by means of a spring device 57 and can be actuated into the flow position 55b by means of an electrical actuating device 58, for example a switching solenoid, which is connected to the electronic control unit 18 for actuation.

[0085] The two-position, two-port valve 56 is designed as a switching valve in the illustrated embodiment.

[0086] In the Fig. The second control valve 55 is designed as a pressure valve 59, in particular a pressure relief valve, with adjustable opening pressure. For changing and adjusting the opening pressure, the pressure valve 59 is equipped with an electrical actuating device 60, for example a switching solenoid or proportional solenoid, which is connected to the electronic control unit 18 for actuation.

[0087] It is understood that, alternatively, the first control valve 50 can be designed as a pressure valve with adjustable opening pressure, and the second control valve 55 as a two-position, two-port valve 56. Furthermore, it is possible to design both the first control valve 50 and the second control valve 55 as pressure valves 59 with adjustable opening pressure.

[0088] It is understood that the designs of the valve assembly 15 of the Fig. 4 and Fig. 5 also in the embodiments of the Fig. 2 and Fig. 3 are applicable.

[0089] Furthermore, the use of a retarder valve 70 is not limited to the embodiment of the Fig. 3 limited, but can also be found in the embodiments of Fig. 1, Fig. 2, Fig. 4 or Fig. 5 are used.

[0090] The displacement machine 1 of the hybrid drive unit H of the Fig. 1 to 5 is connected or can be connected via the drive shaft 11 to a drive train not shown in detail in order to form a hybrid drive train in the form of a parallel hybrid.

[0091] By driving the displacement machine 1 via the drive shaft 11, the displacement machine operates in pump mode. For pump operation, the branch line 6 and the discharge line 10 are shut off by means of the valve assembly 15. The valve assembly 15 of the Fig. 1 to 3 is controlled in the blocked position 20a, the control valves 50, 55 of the valve assembly 15 of the Fig. 4 into the locking positions 50a, 55a actuated or in the Fig. 5 the control valve 50 of the valve assembly 15 is actuated into the closed position 50a and the control valve 55 designed as a pressure valve 59 is set to a maximum opening pressure.

[0092] In pump operation, the positive displacement machine 1, driven via the drive shaft 11, draws hydraulic fluid from the low-pressure accumulator 7 via the suction line 8 and the opening shut-off valve 9, and delivers the hydraulic fluid via the delivery line 2 and the opening shut-off valve 5 into the high-pressure accumulator 3. The shut-off valve 5 in the delivery line 2, which closes towards the positive displacement machine 1, prevents the return flow of hydraulic fluid from the high-pressure accumulator 3 to the delivery side F of the positive displacement machine 1.

[0093] The charging of the high-pressure storage device 3 can occur during operating conditions in which a drive motor of the drivetrain supplies excess energy. In this case, the charging and pressurization of the high-pressure storage device 3 is carried out using excess energy that is generated on the primary side of the drive motor of the drivetrain in certain operating conditions. Alternatively or additionally, the charging of the high-pressure storage device 3 can be carried out by the pump operation of the displacement machine during braking of a consumer of the drivetrain. In this case, the high-pressure storage device 3 is charged by the braking energy, and energy recovery takes place. If the consumer is configured as the drive system of a vehicle, the high-pressure storage device 3 is thus pressurized with hydraulic fluid during braking when the vehicle mass decelerates.Corresponding operating strategies for charging the high-pressure storage device 3 are stored in the electronic control unit 18, which can detect operating states in which the drive motor supplies excess energy or the consumer is braking, based on corresponding input variables. The storage charge state of the high-pressure storage device 3 is monitored by means of the sensor device 17. If the displacement machine 1 is designed as a variable displacement drive, the torque to be absorbed can be set as desired by the electronic control unit 18 by adjusting the displacement volume accordingly.

[0094] Provided the high-pressure storage device 3 is fully charged and this condition is detected by the electronic control unit 18, the energy stored in the high-pressure storage device 3 can be transferred to the drive train by operating the displacement machine 1 via the motor. This is achieved by supplying pressure medium from the high-pressure storage device 3 to the displacement machine 1 at the suction side S. During motor operation, the displacement machine is driven by the pressure medium from the high-pressure storage device 3 and transmits torque to the drive train via the drive shaft 11.

[0095] For engine operation, the branch line 6 and the discharge line 10 are opened and controlled for flow by means of the valve assembly 15. The valve assembly 15 of the Fig. For this purpose, 1 to 3 are controlled in flow position 20b, the control valves 50, 55 of the valve assembly 15 of the Fig. 4 actuated into flow positions 50b, 55b or in the Fig. 5 the control valve 50 of the valve assembly 15 is actuated to the flow position 50b and the control valve 55 designed as a pressure valve 59 is set to a minimum opening pressure.

[0096] During engine operation, pressurized hydraulic fluid from the high-pressure accumulator 3 is supplied to the displacement machine 1 on the suction side S via the open discharge line 10, so that the displacement machine 1 delivers a torque to the drive shaft 11, resulting from the accumulator charging pressure and the set displacement volume, and feeds this torque into the drive train. The shut-off valve 9 in the suction line 8 prevents the hydraulic fluid from flowing out of the high-pressure accumulator 3 into the low-pressure accumulator 7. The delivery line 2 of the displacement machine 1 is connected to the low-pressure accumulator 7 via the open branch line 6, thus allowing the hydraulic fluid driving the displacement machine to flow back from the high-pressure accumulator 3 into the low-pressure accumulator 7.When the displacement machine 1 is designed as a variable displacement drive with adjustable displacement volume, the delivered torque can be adjusted as desired by the electronic control unit 18 by appropriately adjusting the displacement volume.

[0097] By operating the displacement machine 1, a torque supporting the drive motor can be delivered to the drive train while the drive motor is running, thus achieving a boost function. Alternatively or additionally, the operation of the displacement machine 1 can act as a hydraulic starter for a start-stop function of the drive motor of the drive train, which can start the switched-off drive motor 1 within a short time.

[0098] The hybrid drive device H according to the invention, in which the high-pressure storage device 3 forms the only consumer of the displacement machine, enables a compact, simple and cost-effective design, since the suction line 8, the delivery line 2, the branch line 6 and the discharge line 10 of the Fig. 1 to 5 can be formed as channels in a housing in which the valve assembly 15 is arranged and to which the high-pressure storage device 3 and the low-pressure storage device 7 are connected, wherein the housing can be directly attached to a flange surface of a housing of the positive displacement machine 1, which is provided with connections that form the suction side S and the delivery side F of the positive displacement machine 1.

[0099] Furthermore, the invention provides a robust and functionally reliable hydrostatic hybrid drive device H, which offers particular advantages in the context of a start-stop function of the drive motor of the drive train, where a robust and functionally reliable design of the starter of the drive motor is required due to a high number of start operations.

[0100] By designing the displacement machine 1 as an open-circuit displacement machine, which can operate as both a pump and a motor with the same direction of rotation of the drive shaft 11 and the same flow direction of the pressure medium, the displacement machine 1 has a simple and cost-effective design. Designing the displacement machine 1 as a variable displacement drive with adjustable displacement volume offers particular advantages in terms of a simple, compact, and cost-effective design, since only a unidirectional adjustable drive is required, the adjustment of which for the displacement volume control device is simple and compact, resulting in a cost-effective and compact design for the displacement machine designed as a variable displacement drive.

[0101] The hydrostatic hybrid drive unit H according to the invention Fig. Due to their compact and simple design, models 1 to 5 allow for any installation options within a vehicle's powertrain, which are included in the Fig. Sections 6a to 6e illustrate this. Fig. Figures 6a to 6e show a simplified representation of the hydrostatic hybrid drive unit H, showing only the displacement machine 1 and the high-pressure storage device 3.

[0102] In the Fig. Figures 6a to 6e depict the powertrain A of a vehicle, comprising a drive motor AM, for example an internal combustion engine, and a consumer V driven by the drive motor AM. Fig. In figures 6a to 6e, a parallel hybrid is formed by integrating the hydrostatic hybrid drive unit H according to the invention, in which the hybrid drive unit H acts as an energy source for the drive train A in addition to the drive motor AM. Alternatively, an electric motor or a turbine can be provided as the drive motor AM.

[0103] In the Fig. In sections 6a to 6e, the consumer V of the vehicle is designed as a drive system comprising a drive axle AA driven by a transmission G, with at least two driven drive wheels A1, A2. The drive axle AA is designed as a differential axle, wherein a drive shaft AW of the drive train A drives a differential D of the drive axle AA, and the differential D is connected to the driven wheels A1, A2 via drive shafts TW1, TW2.

[0104] The in the Fig. The transmission G shown in 6a to 6e can be designed as a continuously variable hydrostatic transmission, as a mechanical transmission, as a power shift transmission or as a hydrodynamic converter.

[0105] In the Fig. In sections 6a to 6c, the hybrid drive unit H is arranged in a direct through-drive configuration in the drive train A. In this configuration, the displacement machine 1 is driven through, so that the drive shaft 11 of the displacement machine 1 forms part of the drive shaft AW of the drive train A.

[0106] In the Fig. 6a The hybrid drive unit H is arranged in the drive train A between the drive motor AM and the transmission G. The drive shaft AW of the drive train A is equipped with a coupling device K1 between the hybrid drive unit H and the transmission G.

[0107] The Fig. 6b shows a further training of Fig. 6a, wherein a further coupling device K2 is arranged on the drive shaft AW of the drive train A between the drive motor AM and the hybrid drive unit H.

[0108] In the Fig. 6c shows that the hybrid drive unit H is located in the drive train A between the transmission G and the consumer V. The drive shaft AW of the drive train A is equipped with a coupling device K1 between the transmission G and the hybrid drive unit H.

[0109] In the Fig. Figure 6d shows an embodiment in which the vehicle has, in addition to the drive axle AA, which is driven by the drive motor AM via the drive train A, an auxiliary axle ZA, wherein the hybrid drive unit H is connected to the auxiliary axle ZA of the vehicle. The auxiliary axle ZA is designed as a differential axle, wherein the displacement motor 1 of the hybrid drive unit H drives a differential DZ of the auxiliary axle ZA by means of the drive shaft 11, and the differential DZ is connected to the wheels A3, A4 of the auxiliary axle ZA via drive shafts TW3, TW4. A coupling device K3 is arranged in the power flow between the displacement motor 1 of the hybrid drive unit H and the auxiliary axle ZA.

[0110] In the Fig. Figure 6e shows an embodiment in which the hybrid drive unit H is connected to the drive train A via a displacement transmission VG. In the illustrated embodiment, the displacement transmission VG is designed as a spur gear transmission comprising a spur gear S1 connected to the drive shaft AW and a spur gear S2 meshing with the spur gear S1, which is connected to the drive shaft 11 of the displacement machine 1. The displacement transmission VG makes it possible to arrange the displacement machine 1 with its drive shaft 11 parallel to and spaced apart from the drive shaft AW of the drive train A. Fig. 6e further provides a coupling device K4, by means of which the hybrid drive unit H can be connected to or disconnected from the drive train A. In the illustrated embodiment, the coupling device K4 is arranged between the drive shaft AW of the drive train A and the spur gear S1 of the transfer gearbox VG.

[0111] In the Fig. 6e the hybrid drive unit H is integrated in the drive train A between the drive motor AM and the coupling unit K1 and thus the hybrid drive unit H in the drive train A between the drive motor AM and the transmission G driving the consumer V according to the Fig. 6a. It is understood that the connection of the hybrid drive unit H to the drive train A by means of the transfer gear VG can be used analogously in variants 6b to 6d.

[0112] As from the Fig.As illustrated in Figures 6a to 6e, the hydrostatic hybrid drive unit H according to the invention, due to its compact and simple design, can be easily installed at any point in a drive train as an additional energy source to form a parallel hybrid. The hydrostatic hybrid drive unit H according to the invention can therefore be easily adapted to different drive trains and different vehicles. The hydrostatic hybrid drive unit H according to the invention can be combined with different transmissions G.

Claims

[1] Hydrostatic hybrid drive device (H) for a hybrid powertrain (A), in particular of a vehicle, comprising a drive motor (AM) and a consumer (V) driven by the drive motor (AM), characterized bythat the hybrid drive device (H) comprises only a hydrostatic displacement machine (1) which is operated in an open circuit and can be operated as a pump and motor with the same direction of rotation and the same flow direction of a pressure medium, wherein the displacement machine (1) is designed as a variable displacement drive with unilateral adjustability in the displacement volume and a displacement volume adjusting device (1a) of the variable displacement drive is adjustable from a position with minimum displacement volume in one adjusting direction, wherein a delivery line (2) is connected to an outlet-side delivery side (F) of the displacement machine (1) which leads to a high-pressure storage device (3), wherein the displacement machine (1) in pump mode delivers exclusively to the high-pressure storage device (3), which is the only consumer supplied by the displacement machine (1),and a shut-off valve (5) opening towards the high-pressure storage device (3) is arranged in the delivery line (2), wherein a branch line (6) branches off from the delivery line (2) between the delivery side (F) of the positive displacement machine (1) and the shut-off valve (5), which is connected to a low-pressure storage device (7), and an intake line (8) connected to the low-pressure storage device (7) is connected to an inlet-side suction side (S) of the positive displacement machine (1), wherein a shut-off valve (9) opening towards the low-pressure storage device (7) is arranged in the intake line (8), and a discharge line (10) is connected from the high-pressure storage device (3) to the intake line (8) between the suction side (S) of the positive displacement machine (1) and the shut-off valve (9), wherein a valve assembly (15) is provided which controls the discharge line (10) and the branch line (6),wherein the valve device (15) shuts off the discharge line (10) and the branch line (6) during pump operation of the positive displacement machine (1) and controls the discharge line (10) and the branch line (6) to allow flow during motor operation of the positive displacement machine (1). [2] Hydrostatic hybrid drive device according to claim 1, characterized by , that the valve assembly (15) is designed as a two-position four-port valve (20) to which the branch line (6) and the discharge line (10) are connected, wherein the two-position four-port valve (20) has a closed position (20a) in which the branch line (6) and the discharge line (10) are closed, and a flow position (20b) in which the branch line (6) and the discharge line (10) are open. [3] Hydrostatic hybrid drive device according to claim 2, characterized by , that the two-position four-port valve (20) is designed as a switching valve. [4] Hydrostatic hybrid drive device according to claim 1, characterized by , that the valve assembly (15) has a first control valve (50) that controls the discharge line (10) and a second control valve (55) that controls the branch line (6). [5] Hydrostatic hybrid drive device according to claim 4, characterized by , that the first control valve (50) and / or the second control valve (55) is designed as a two-position two-port valve (51; 56) having a closed position (50a; 55a) and a flow position (50b; 55b). [6] Hydrostatic hybrid drive device according to claim 4 or 5, characterized by , that the first control valve (50) and / or the second control valve (55) is designed as a switching valve. [7] Hydrostatic hybrid drive device according to claim 4, characterized by, that the first control valve (50) and / or the second control valve (55) is designed as a pressure valve (59) with adjustable opening pressure, in particular a pressure relief valve. [8] Hydrostatic hybrid drive device according to any one of claims 1 to 7, characterized by , that the valve device (15) is electrically actuated and is connected for actuation to an electronic control device (18) which is connected on the input side to a sensor device (17) which detects the storage pressure of the high pressure storage device (3). [9] Hydrostatic hybrid drive device according to claim 8, characterized by, that operating strategies are stored in the electronic control unit (18) to charge the high-pressure storage device (3) depending on the operating conditions of the vehicle with excess energy from the drive motor (AM) and / or during braking operation of the consumer (V) by means of a pump operation of the displacement machine (1). [10] Hydrostatic hybrid drive device according to any one of claims 1 to 9, characterized by , that the displacement machine (1) serves as a booster drive for the running drive motor (AM) and / or as a hydraulic starter for the switched-off drive motor (AM) during motor operation. [11] Hydrostatic hybrid drive device according to any one of claims 1 to 10, characterized by , that a pressure relief valve (16) is associated with the high-pressure storage device (3). [12] Hydrostatic hybrid drive device according to any one of claims 1 to 11, characterized by, that the high-pressure storage device (3) is designed as a pressure storage device (3a), in particular a bladder storage device, piston storage device or diaphragm storage device. [13] Hydrostatic hybrid drive device according to any one of claims 1 to 12, characterized by , that the low-pressure storage device (7) is designed as a container (7a), in particular a non-prestressed container, or as a pressure storage device (7b), in particular a prestressed container, bladder storage device, piston storage device or diaphragm storage device. [14] Hydrostatic hybrid drive device according to any one of claims 1 to 11, characterized by, that the high-pressure storage device (3) and the low-pressure storage device (7) are designed as a double-piston storage device (30), wherein a first pressure chamber (36; 39) of the double-piston storage device (30) is connected to the delivery line (2) and the discharge line (10) and a second pressure chamber (37; 38) of the double-piston storage device (30) is connected to the branch line (6) and the suction line (8). [15] Hydrostatic hybrid drive device according to any one of claims 8 to 14, characterized by , that the displacement volume control device (1a) of the adjustment drive is connected to the electronic control device (18) for control. [16] Hydrostatic hybrid drive device according to any one of claims 1 to 15, characterized by , that a retarder valve (70) is arranged in the delivery line (2).

Images