Idle circuit for a hydraulic actuator of a wind turbine

Abstract

The invention relates to an arrangement (103) for an actuator (101) of a wind turbine; comprising a motor (105) and a first line arrangement (107a) which is hydraulically connected to a first connection of the motor (105) and which is or can be hydraulically connected to a pump (115). Via a second line arrangement (107b), the first connection of the motor (105) is hydraulically connected to a fluid reservoir (117); wherein the second line arrangement (107b) has a first check valve (121a) which allows flow from the fluid reservoir (117) towards the first connection of the motor (105) and prevents flow in the opposite direction.

Description

[0001] ZF Friedrichshafen AG File 300977 Friedrichshafen 2025-01-10

[0002] Idle circuit for a hydraulic actuator of a wind turbine

[0003] The invention relates to an arrangement for an actuator of a wind turbine according to the preamble of claim 1.

[0004] From WO 2021190719 A1, a hydraulic actuator for a wind turbine with a pump and several motors is known. The actuator has a directional control valve with which the direction of rotation of the motors can be reversed. Further directional control valves serve to connect the motors to the pump either in series or in parallel.

[0005] The invention is based on the objective of providing an improved actuator for a wind turbine compared to the prior art. This objective is achieved by an arrangement according to claim 1. Preferred embodiments are included in the dependent claims and will become apparent from the following description and the exemplary embodiments.

[0006] The arrangement according to the invention comprises a motor and a first line arrangement.

[0007] A piping assembly is a hydraulically conductive connection with one or more lines that are hydraulically connected or connectable in pairs. The lines can be connected directly or via other hydraulic components belonging to the piping assembly, such as directional control valves or check valves. If one hydraulic component is hydraulically connected to another hydraulic component via a piping assembly, the piping assembly forms a hydraulically conductive connection between the two components.

[0008] A hydraulically conductive connection is a connection capable of carrying fluid and pressure. The connection is designed to conduct pressurized hydraulic fluid. ZF Friedrichshafen AG File 300977 Friedrichshafen 2025-01-10

[0009] The first line assembly is hydraulically connected to a first port of the motor. Furthermore, the first line assembly is hydraulically connected, or connectable, to a pump. This establishes a hydraulically conductive connection between the pump and the motor via the first line assembly. The first line assembly is therefore designed to convey hydraulic fluid, pressurized by the pump, to the motor. This allows the motor to be driven by the pump.

[0010] In addition to the first line arrangement, the arrangement according to the invention has a second line arrangement. According to the invention, the first connection of the motor is hydraulically connected to a fluid reservoir via the second line arrangement.

[0011] The second piping arrangement includes a first check valve. This valve is open from the fluid reservoir towards the first connection of the motor. In the opposite direction, that is, from the first connection of the motor towards the fluid reservoir, the first check valve blocks flow.

[0012] When the first line assembly is pressurized with hydraulic pressure by the pump, the motor rotates in a first direction. The check valve prevents hydraulic fluid from escaping into the fluid reservoir via the second line assembly.

[0013] Since the first check valve is open from the fluid reservoir towards the motor, the motor can be operated in the first direction at idle. The motor is rotated in the first direction by an external drive not belonging to the present arrangement. This causes the motor of the arrangement according to the invention to act as a pump and apply a vacuum to the first port. Consequently, the motor draws hydraulic fluid from the fluid reservoir via the second line arrangement. ZF Friedrichshafen AG File 300977 Friedrichshafen 2025-01-10

[0014] Preferably, the arrangement is further developed with a switchable pressure limiting arrangement, a third line arrangement, a fourth line arrangement, a fifth line arrangement and a directional control valve.

[0015] The pressure limiting device is designed to limit the maximum pressure that can be transmitted via a hydraulically connected pipe assembly. Specifically, this means that the pressure limiting device is designed to limit the pressure exerted on the hydraulic fluid conveyed by the pipe assembly.

[0016] The pressure limiting device is switchable between a first state, in which it limits the maximum pressure transmittable through the pipework to the first maximum pressure, and a second state, in which it limits the maximum pressure transmittable through the pipework to the second maximum pressure. In the first state, the pressure limiting device prevents the pressure transmitted through the pipework from exceeding the first maximum pressure. Similarly, in the second state, the pressure limiting device prevents the pressure transmitted by the pipework from exceeding the second maximum pressure.

[0017] The third line assembly connects the first motor port hydraulically to the pressure relief device. This third line assembly includes a second check valve. This check valve allows flow from the first motor port towards the pressure relief device and blocks flow in the opposite direction, i.e., from the pressure relief device towards the first port.

[0018] During idling operation of the engine in the first direction of rotation, the engine pumps the hydraulic fluid drawn from the fluid reservoir via the first line assembly and pressurizes the third line assembly. The second maximum pressure of the pressure relief assembly is preferably lower than the first maximum pressure. The second maximum pressure can also be zero. ZF Friedrichshafen AG File 300977 Friedrichshafen 2025-01-10

[0019] To offer the least possible resistance to the rotation of the engine, the pressure limiting arrangement is switched to the second state for idle operation.

[0020] A second motor connection is hydraulically connected to the pressure relief device via the fourth line. This fourth line includes a third check valve. This valve allows flow from the second connection towards the pressure relief device and blocks flow in the opposite direction, i.e., from the pressure relief device towards the second connection.

[0021] The further training stipulates that the first connection of the motor is hydraulically connected to the directional control valve via the first line arrangement. For this purpose, the first connection of the motor can be hydraulically connected to a first connection of the directional control valve via the first line arrangement.

[0022] Similarly, a second connection of the motor is hydraulically connected to the directional control valve via the fifth line arrangement. The directional control valve can have a second connection, with the second connection of the motor being hydraulically connected to the second connection of the directional control valve via the fifth line arrangement.

[0023] The directional control valve has at least two switching positions – a first switching position and a second switching position. In the first switching position, the first line assembly is hydraulically connected to the pump. The directional control valve may also have a third port, which is hydraulically connected to the pump via a line assembly referred to as the supply line. In the first switching position, the directional control valve then establishes a hydraulically conductive connection between the first port and the third port of the directional control valve.

[0024] In the second switching position of the directional control valve, the fifth line assembly is hydraulically connected to the pump. In particular, the directional control valve in the second switching position can establish a hydraulically conductive connection between the second ZF Friedrichshafen AG File 300977 Friedrichshafen 2025-01-10

[0025] Connect the fifth pipe assembly to the third connection of the directional control valve. This creates a hydraulically conductive connection between the fifth pipe assembly and the supply line.

[0026] Preferably, the directional control valve has a fourth port that is hydraulically connected to a pipe assembly designated as the return line. In the first switching position, the directional control valve preferably establishes a hydraulically conductive connection between the fifth pipe assembly and the fourth port of the directional control valve, and thus between the fifth pipe assembly and the drain line. Similarly, in the second switching position, the directional control valve preferably establishes a hydraulically conductive connection between the first port and the fourth port. The first pipe assembly is then hydraulically connected to the drain line.

[0027] The drain line is designed to drain hydraulic fluid from the fourth port of the directional control valve into the fluid reservoir. Hydraulic fluid entering the drain line via the fourth port of the directional control valve flows through the drain line into the fluid reservoir.

[0028] The first switching position of the directional control valve is used to operate the motor in the first direction of rotation. The pump then pressurizes the first hydraulic line to drive the motor. In this operating state, the pressure relief device is set to the first maximum pressure. Since the second check valve is open in the direction of the pressure relief device, the pressure at the first motor port is limited to the first maximum pressure. Therefore, the motor operates in the first direction of rotation with a pressure at the first port that corresponds to the first maximum pressure, or is lower if the pump pressurizes the first line at a lower pressure.

[0029] By switching the directional control valve to the second switching position, the motor is operated in the opposite direction, that is, in a second direction different from the first. The fifth line arrangement is connected in this operating state. ZF Friedrichshafen AG File 300977 Friedrichshafen 2025-01-10

[0030] The motor is subjected to pressure generated by the pump. The pressure limiting device is set to the first maximum pressure, thus limiting the pressure in the fifth line assembly to this first maximum pressure. If the pressure applied by the pump is lower than the first maximum pressure, the motor is driven at this lower pressure via the fifth line assembly. Otherwise, the pressure is limited to the first maximum pressure by the pressure limiting device, so the motor is driven in the second direction of rotation at this first maximum pressure.

[0031] Preferably, the arrangement is further developed with a sixth line assembly. The second connection of the motor is hydraulically connected to the fluid reservoir via this sixth line assembly. The sixth line assembly includes a fourth check valve. This check valve is open from the fluid reservoir towards the second connection of the motor and is closed in the opposite direction, i.e., from the second connection of the motor towards the fluid reservoir.

[0032] Analogous to the first line arrangement, the sixth line arrangement allows the motor to run at idle, but unlike the first, in the opposite direction, i.e., in the second direction. If the motor is turned in the second direction of rotation by an external drive not belonging to this arrangement, the sixth line arrangement allows the rotor to draw hydraulic fluid from the fluid reservoir via the second connection.

[0033] Even during idling operation in the second direction of rotation, the pressure limiting arrangement is preferably switched to the second state, so that the motor offers the least possible resistance to rotation.

[0034] The directional control valve is preferably further developed with a third switching position. In the third switching position, the directional control valve hydraulically isolates the first line arrangement and / or the fifth line arrangement. In particular, the directional control valve can be found in ZF Friedrichshafen AG File 300977 Friedrichshafen 2025-01-10

[0035] In the third switching position, hydraulically isolate the first and / or third connection of the directional control valve.

[0036] The third switching position of the directional control valve is used for idling the engine. Therefore, it is preferable to switch the third switching position of the directional control valve together with the second state of the pressure relief device to operate the engine at idle.

[0037] The arrangement is preferably further developed as a first arrangement of an actuator for a wind turbine. In addition to the first arrangement, the actuator has a second arrangement. The second arrangement is also designed as an arrangement according to the invention or a preferred further development.

[0038] The motor of the first arrangement and the motor of the second arrangement are effectively connected, or connectable, to a drive train of the wind turbine. With an effective connection, rotation of the drive train is accompanied by rotation of the motor of the first drive arrangement and rotation of the motor of the second drive arrangement. Conversely, rotation of the motor of the first drive arrangement and rotation of the motor of the second drive arrangement is accompanied by rotation of the drive train. Rotation of the drive train in the opposite direction is accompanied by rotation of the motor of the first drive arrangement and rotation of the motor of the second drive arrangement in the opposite direction. Finally, rotation of the motor of the first drive arrangement and rotation of the motor of the second drive arrangement in the opposite direction is accompanied by rotation of the drive train in the opposite direction.

[0039] If the directional control valves of the first and second arrangements are in the first switching position and the pressure limiting devices of the first and second arrangements are switched to the first state, the motors of the first and second arrangements can be driven simultaneously in the first direction of rotation. Switching the directional control valves to the second switching position reverses the direction of rotation. The drive train is then driven by both motors. Alternatively, it is possible to run one of the motors in neutral. ZF Friedrichshafen AG File 300977 Friedrichshafen 2025-01-10

[0040] To operate, preferably the directional control valve of the first arrangement or the directional control valve of the second arrangement is moved to the third switching position. This corresponds to switching the pressure limiting arrangement of the arrangement whose motor is running at idle to the second state.

[0041] In a preferred embodiment, a gear is provided as part of the drive-related connection between the motors and the drive train. According to this embodiment, a drive pinion of the first motor and a drive pinion of the second motor mesh with this gear. The gear, in turn, is effectively connected to the drive train or can be connected to it. The gear can be part of the drive train and be designed to transmit torque from a wind-driven rotor of the wind turbine to a generator. Alternatively, it can be a separate gear that is rotationally fixed to or connectable to a shaft of the drive train, or that engages with or can be brought into engagement with a gear of the drive train.

[0042] A preferred embodiment of the invention is shown in Fig. 1. Specifically, it shows:

[0043] Fig. 1 shows an actuator of a wind turbine.

[0044] The actuator 101 shown in Fig. 1 comprises several identical motor assemblies 103. Each motor assembly 103 includes a motor 105, which is used to position a wind-driven rotor of the wind turbine. For this purpose, the motors 105 are connected, or can be connected, to a drive train of the wind turbine.

[0045] The motor arrangements 103 also each comprise a first line arrangement 107a, a second line arrangement 107b, a third line arrangement 107c, a fourth line arrangement 107d, a fifth line arrangement 107e, a sixth line arrangement 107f, a pressure limiting arrangement 109 and a directional control valve 111. ZF Friedrichshafen AG File 300977 Friedrichshafen 2025-01-10

[0046] The first line assembly 107a establishes a hydraulically conductive connection between a first port of the directional control valve 111 and a first port of the motor 105. A second port of the directional control valve 111 is hydraulically connected to a second port of the motor 105 via the fifth line assembly 107e. A third port of the directional control valve 111 is hydraulically connected via a supply line 113 to a pump 115, which is supplied via a fluid reservoir 117. A fourth port of the directional control valve 111 is hydraulically connected to a return line 119.

[0047] The second pipe arrangement 107b has a first check valve 121a, the third pipe arrangement 107c has a second check valve 121b, the fourth pipe arrangement 107d has a third check valve 121c and the sixth pipe arrangement 107f has a fourth check valve 121d.

[0048] The second line assembly 107b hydraulically connects the fluid reservoir 117 to the first connection of the pump 105. For this purpose, one outlet of the second line assembly 107b is located below the level of the hydraulic fluid contained in the fluid reservoir 117. The first check valve 121a is permeable from the fluid reservoir 117 towards the motor 105 and is blocked in the opposite direction.

[0049] Analogous to the second line assembly 107b, the sixth line assembly 107f hydraulically connects the liquid reservoir 117 to a second connection of the motor 105. One outlet of the sixth line assembly 107f is also located below the water level. The fourth check valve 121d is permeable from the liquid reservoir 117 towards the motor 105 and is blocked in the opposite direction.

[0050] The third line assembly 107c hydraulically connects the pressure relief assembly 109 to the first port of the pump 105. Similarly, the fourth hydraulic line 107d hydraulically connects the pressure relief assembly 109 to the second port of the pump 105. The second check valve 121b extends from the motor 105 towards the pressure relief assembly 109. ZF Friedrichshafen AG File 300977 Friedrichshafen 2025-01-10

[0051] The third pressure relief valve 121 is permeable in the direction of the motor and blocks in the opposite direction. Likewise, the third pressure relief valve 121 is permeable in the direction of the pressure relief arrangement 109 from the motor and blocks in the opposite direction.

[0052] In the first switching position of the directional control valve 111, the first port of the directional control valve is hydraulically connected to the third port of the directional control valve. The second port of the directional control valve 111 is hydraulically connected to the fourth port of the directional control valve 111.

[0053] In a second switching position of the directional control valve 111, the ports are cross-connected. In this second switching position, the first port of the directional control valve 111 is hydraulically connected to the fourth port of the directional control valve 111. Furthermore, in this second switching position, the second port of the directional control valve 111 is hydraulically connected to the third port of the directional control valve 111. By switching the directional control valve from the first switching position to the second switching position, the direction of rotation of the motor 105 can be reversed. The pressure relief device 109 is configured to allow a pressure sufficient to drive the motor 105.

[0054] In a third switching position of the directional control valve 111, the first and second ports of the directional control valve 111 are hydraulically isolated. If the maximum pressure of the pressure relief device 109 is now significantly reduced or set to zero, the motor 105 can be operated in idle mode while the actuator is operated by one or more motors 105 of the other drive units 103. The directional control valves 111 of these drive units 103 are in their first or second switching position. ZF Friedrichshafen AG File 300977

[0055] Friedrichshafen 2025-01-10

[0056] Reference mark

[0057] 101 Actuator

[0058] 103 Engine arrangement

[0059] 105 engine

[0060] 107a Line arrangement

[0061] 107b Management arrangement

[0062] 107c Line arrangement

[0063] 107d Line arrangement

[0064] 107e Management arrangement

[0065] 107f Line arrangement

[0066] 109 Pressure relief arrangement

[0067] 111-way valve

[0068] 113 Inlet pipe

[0069] 115 pump

[0070] 117 Liquid reservoir

[0071] 119 Return line

[0072] 121a Check valve

[0073] 121b Check valve

[0074] 121c Check valve

[0075] 121d Check valve

Claims

ZF Friedrichshafen AG File 300977 Friedrichshafen 2025-01-10 Patent claims 1. Arrangement (103) for an actuator (101) of a wind turbine; comprising a motor (105) and a first line arrangement (107a) which is hydraulically connected to a first port of the motor (105) and which is hydraulically connected or connectable to a pump (115); characterized by a second line arrangement (107b) via which the first port of the motor (105) is hydraulically connected to a fluid reservoir (117); wherein the second line arrangement (107b) has a first check valve (121a) which is open from the fluid reservoir (117) in the direction of the first port of the motor (105) and is closed in the opposite direction.

2. Arrangement (103) according to claim 1; characterized by a pressure limiting arrangement (109) switchable between a first maximum pressure and a second maximum pressure, a directional control valve (111), a third line arrangement (107c) via which the first port of the motor (105) is hydraulically connected to the pressure limiting arrangement (109), a fourth line arrangement (107d) via which a second port of the motor (105) is hydraulically connected to the pressure limiting arrangement (109), and a fifth line arrangement (107e); wherein the first connection of the motor (105) is hydraulically connected to the directional control valve (111) via the first line arrangement (107a) and the second connection of the motor (105) is hydraulically connected to the directional control valve (111) via the fifth line arrangement (107e); wherein the third line arrangement (107c) has a second check valve (121b) which is open from the first port of the motor (105) towards the pressure limiting arrangement (109) and is closed in the opposite direction; wherein the fourth line arrangement (107d) has a third check valve (121c) which is open from the second port of the motor (105) towards the pressure limiting arrangement (109) and is closed in the opposite direction; wherein in a first switching position of the directional control valve (111) the first line arrangement (107a) is hydraulically connected to the pump (115); wherein In a second switching position of the directional control valve (111), the fifth line arrangement (107e) is hydraulically connected to the pump (115). ZF Friedrichshafen AG File 300977 Friedrichshafen 2025-01-10 3. Arrangement (103) according to the preceding claim; characterized by a sixth line arrangement (107f) via which the second connection of the motor (105) is hydraulically connected to the fluid reservoir (117); wherein the sixth line arrangement (107f) has a fourth check valve (121d) which is continuous from the fluid reservoir (117) in the direction of the second connection of the motor (105) and is blocked in the opposite direction.

4. Arrangement (103) according to one of the preceding two claims; characterized by a third switching position of the directional control valve (111); wherein In the third switching position, the directional control valve (111) hydraulically isolates the first line arrangement (107a) and / or the fifth line arrangement (107e) from the pump (115).

5. Actuator for a wind turbine; characterized by a first arrangement (103) and a second arrangement (103) according to one of the preceding claims; wherein the motor (105) of the first arrangement (103) and the motor (105) of the second arrangement (103) are effectively connected or connectable to a drive train of the wind turbine.

6. Actuator according to the preceding claim; characterized by a gear; wherein a drive pinion of the motor (105) of the first arrangement (103) and a drive pinion of the motor (105) of the second arrangement (103) mesh with the gear; wherein the gear is effectively connected or connectable to the drive train.

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