Switchable hydraulic actuator for a wind turbine

Abstract

The invention relates to an actuator (101) for a wind turbine; the actuator having at least one motor (115), at least one pump (103), and a first line arrangement (107) via which the pump (103) is or can be hydraulically conductively connected to the motor (115). A pressure-limiting arrangement (119), which can be switched between a first maximum pressure and a second maximum pressure, is provided for limiting the pressure which can be transmitted via the first line arrangement (107).

Description

[0001] ZF Friedrichshafen AG File 300978 Friedrichshafen 2025-01-10

[0002] Switchable hydraulic actuator for a wind turbine

[0003] The invention relates to an actuator for 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 a hydraulic actuator according to claim 1. Preferred embodiments are included in the dependent claims and will become apparent from the following description and the exemplary embodiment.

[0006] An actuator for a wind turbine is a drive that allows the wind-driven rotor of the wind turbine to be rotated and positioned for assembly or repair purposes.

[0007] The actuator according to the invention comprises at least one motor, at least one pump, and a first line arrangement. The first line arrangement is configured to convey hydraulic fluid, pressurized by the pump, to the motor.

[0008] A piping arrangement is a hydraulically conductive connection with one or more lines that are hydraulically connected or connectable to each other in pairs. The lines can be connected directly or via other hydraulic components belonging to the piping arrangement, such as directional control valves or check valves. If a hydraulic component is hydraulically connected to another hydraulic component via a piping arrangement, ZF Friedrichshafen AG File 300978 Friedrichshafen 2025-01-10

[0009] The pipe arrangement thus forms a hydraulically conductive connection between the two components.

[0010] A hydraulically conductive connection is a connection that conducts fluid and pressure. The connection is designed to conduct pressurized hydraulic fluid.

[0011] In this case, the pump is hydraulically connected, or connectable, to the motor via the first piping arrangement. Accordingly, the pump can be a hydraulic pump and the motor a hydraulic motor.

[0012] According to the invention, the actuator has a pressure limiting arrangement that can be switched between a first maximum pressure and a second maximum pressure. The first maximum pressure differs in magnitude from the second maximum pressure. In particular, the second maximum pressure can be greater than the first maximum pressure.

[0013] The pressure limiting device is designed to limit the maximum pressure that can be transmitted through the first line assembly. Specifically, this means that the pressure limiting device is designed to limit the pressure exerted on the hydraulic fluid conveyed from the pump to the motor via the first line assembly. The pressure limiting device is configured to operate in two states: a first state, in which it limits the pressure transmitted through the first line assembly to the first maximum pressure, and a second state, in which it limits the pressure transmitted through the first line assembly to the second maximum pressure. In the first state, the pressure limiting device prevents the pressure transmitted through the first line assembly from exceeding the first maximum pressure.Accordingly, in the second state, the pressure limiting arrangement prevents the pressure transmitted by the first line arrangement from exceeding the second maximum pressure. ZF Friedrichshafen AG File 300978 Friedrichshafen 2025-01-10.

[0014] The actuating torque applied by the at least one motor for rotating the rotor of the wind turbine depends on the pressure transmitted via the first line arrangement. Therefore, the invention makes it possible to regulate the actuating torque applied by the motor by switching the pressure limiting arrangement.

[0015] Preferably, the pressure relief arrangement is further developed with a first pressure relief valve and a second pressure relief valve. A pressure relief valve has at least two ports – a port P and a port T. When the pressure of the hydraulic fluid at port P reaches an opening pressure, the pressure relief valve establishes a hydraulically conductive connection between port P and port T and allows a portion of the hydraulic fluid to flow out through port T until the pressure at port P falls below the opening pressure. The opening pressure of the first pressure relief valve corresponds to the first maximum pressure, and the opening pressure of the second pressure relief valve corresponds to the second maximum pressure.

[0016] The further training stipulates that the first and second pressure relief valves can be alternately connected to the first piping assembly. This means that the first and second pressure relief valves can be hydraulically connected to the first piping assembly in either direction. Specifically, the port P of the first pressure relief valve and the port P of the second pressure relief valve can be hydraulically connected to the first piping assembly in either direction. The pressure relief assembly can therefore be operated in such a way that there is a hydraulically conductive connection between the first piping assembly and port P of the first pressure relief valve, or a hydraulically conductive connection between the first piping assembly and port P of the second pressure relief valve.Further training is advantageous because the pressure relief valves result in a particularly simple and cost-effective implementation of the pressure relief arrangement. ZF Friedrichshafen AG File 300978 Friedrichshafen 2025-01-10.

[0017] For a simple and cost-effective design of the pressure relief arrangement, it is also advantageous to incorporate a first directional control valve. This first directional control valve allows the first and second pressure relief valves to be alternately connected to the first piping arrangement. Specifically, the first directional control valve has at least two switching states. In the first switching state, the first directional control valve establishes a hydraulically conductive connection between the first piping arrangement and the first pressure relief valve. Similarly, in the second switching state, the first directional control valve establishes a hydraulically conductive connection between the first piping arrangement and the second pressure relief valve. Furthermore, in the first switching state, the second pressure relief valve is hydraulically isolated from the first piping arrangement.Accordingly, in the second switching state, the first pressure relief valve is hydraulically isolated from the first pipe arrangement.

[0018] Two components are hydraulically isolated from each other if there is no hydraulically conductive connection between them. In particular, the transmission of pressure acting on the hydraulic fluid between the components is prevented.

[0019] Preferably, the actuator is further developed with a second directional control valve. The second directional control valve serves to reverse the direction of rotation of the at least one motor. To connect the second directional control valve accordingly, the actuator, according to the further development, comprises a second line arrangement and a third line arrangement.

[0020] The second-way valve has a first port, a second port, and a third port. In its first switching position, the second-way valve establishes a hydraulically conductive connection between the first and second ports. The third port may be hydraulically isolated in the first switching position. ZF Friedrichshafen AG File 300978 Friedrichshafen 2025-01-10

[0021] In a second switching position, the two-way valve establishes a hydraulically conductive connection between the first and third ports. The second port can be hydraulically isolated in this second switching position.

[0022] According to the further development, the at least one pump is hydraulically connected to the first port of the second directional control valve via the first piping arrangement. Thus, according to the further development, the first piping arrangement forms a hydraulically conductive connection between the at least one pump and the first port.

[0023] The second port is hydraulically connected to a first port of at least one motor via the second piping arrangement. The second piping arrangement thus forms a hydraulically conductive connection between the second port of the second directional control valve and the first port of the motor.

[0024] Furthermore, the advanced design stipulates that the third port of the second directional control valve is hydraulically connected to a second port of the at least one motor via the third piping arrangement. Thus, the third piping arrangement establishes a hydraulically conductive connection between the third port of the second directional control valve and the second port of the at least one motor.

[0025] In the first switching position, the first line arrangement is hydraulically connected to the second line arrangement via the second directional valve. This creates a hydraulically conductive connection between the at least one pump and the first connection of the at least one motor.

[0026] In the second switching position, the first line assembly is hydraulically connected to the third line assembly via the second directional control valve. This creates a hydraulically conductive connection between the at least one pump and the second connection of the at least one motor. As a result, the direction of rotation of the at least one motor changes. ZF Friedrichshafen AG File 300978 Friedrichshafen 2025-01-10

[0027] A preferred embodiment of the invention is shown in Fig. 1. Specifically, it shows:

[0028] Fig. 1 shows a hydraulic actuator for a wind turbine.

[0029] The actuator 101 shown in Fig. 1 has a pump 103. This pump is designed to draw hydraulic fluid from a reservoir 105, pressurize it, and deliver it via a first line arrangement 107. The first line arrangement 107 is connected via a directional control valve 109 to a second line arrangement 111 and a third line arrangement 113.

[0030] To position a rotor of the wind turbine, the actuator has several motors 115. The motors 115 are each connected to the second line arrangement 111 and the third line arrangement 113 via a safety circuit 117, which retains any hydraulic fluid that may escape in the event of damage to a line.

[0031] If the first line assembly 107 is hydraulically connected to the second line assembly 111 via the first directional control valve 109, the motors 115 are driven by the pump in a first direction of rotation. The motors 115 are driven by the pump 103 in a second, opposite direction of rotation when the first line assembly 107 is hydraulically connected to the third line assembly 113 via the directional control valve 109.

[0032] To limit the pressure in the first line assembly 107, and thus the maximum pressure transmitted from the pump 103 to the motors 115, a pressure limiting assembly 119 is provided. The pressure limiting assembly 119 has a first stage 121a, a second stage 121b, and a third stage 121c. Each stage 121a, 121b, 121c includes a pressure limiting valve 123a, 123b, 123c. This valve limits the hydraulic pressure transmitted from the pump 103 to the motors 115 via the first line assembly 107 to the respective opening pressure. The opening pressure of the pressure relief valve 123a of the first stage 121a is lower than the opening pressure of the pressure relief valve 123b of the second stage. ZF Friedrichshafen AG File 300978 Friedrichshafen 2025-01-10

[0033] which in turn is lower than the opening pressure of the pressure relief valve 123c of the third stage 121c.

[0034] The first stage 121a and the second stage 121b each have an upstream directional control valve 125a, 125b. If a fourth stage is provided, the third stage 121c can also have a corresponding directional control valve.

[0035] In the first switching position of the directional control valve 125a of the first stage 121a, a hydraulically conductive connection is established via the directional control valve 125a between the first line assembly 107 and the pressure relief valve 123a of the first stage 121a. This results in the maximum hydraulic pressure that can be transmitted via the first line assembly 107 being limited to the opening pressure of the pressure relief valve 123a of the first stage 121a.

[0036] In a second switching position of the directional control valve 125a of the first stage 121a, the directional control valve 125a hydraulically isolates the other components of the first stage 121a from the first line arrangement 107. Instead, a hydraulically conductive connection is established via the directional control valve 125a between the first line arrangement 107 and the directional control valve 125b of the second stage 121b.

[0037] In its first switching position, the directional control valve 125b of the second stage 121b switches through to the second stage 121. This allows a hydraulically conductive connection to be established between the first line assembly 107 and the pressure relief valve 123b of the second stage 121b via the directional control valve 125a of the first stage 121a and the directional control valve 125 of the second stage 121. The maximum hydraulic pressure that can be transmitted via the first line assembly 107 is then limited to the opening pressure of the pressure relief valve 123b of the second stage 121b.

[0038] In a second switching position, the directional control valve 125b of the second stage 121b hydraulically isolates the remaining components of the second stage 121b and instead establishes a hydraulically conductive connection to the third stage 121c. This enables a hydraulically conductive connection via the directional control valves 125a, 125b between the first line assembly 107 and the pressure relief valve 123c of the third stage. ZF Friedrichshafen AG File 300978 Friedrichshafen 2025-01-10

[0039] Stage 121c. The hydraulic pressure that can be transmitted via the first line arrangement 107 is then limited to the opening pressure of the pressure relief valve 123c of the third stage 121c.

[0040] Additionally, each stage 121a, 121b, 121ce has a pressure relief valve 127a, 127b, 127c with a low opening pressure, which is activated via a further directional control valve 129a, 129b, 129c and can be hydraulically connected to the first line assembly 107. The low opening pressure allows the pump 103 to be operated at idle. ZF Friedrichshafen AG File 300978

[0041] Friedrichshafen 2025-01-10

[0042] Reference mark

[0043] 101 Actuator

[0044] 103 Pump

[0045] 105 Reservoir

[0046] 107 Management arrangement

[0047] 109-way valve

[0048] 111 Line arrangement

[0049] 113 Line arrangement

[0050] 115 engine

[0051] 117 Safety circuit

[0052] 119 Pressure relief arrangement

[0053] 121a Stage

[0054] 121b Level

[0055] 121c Level

[0056] 123a Pressure relief valve

[0057] 123b Pressure relief valve

[0058] 123c Pressure Relief Valve

[0059] 125a directional control valve

[0060] 125b directional control valve

[0061] 127a Pressure relief valve

[0062] 127b Pressure relief valve

[0063] 127c Pressure Relief Valve

Claims

ZF Friedrichshafen AG File 300978 Friedrichshafen 2025-01-10 Patent claims 1. Actuator (101) for a wind turbine; comprising at least one motor (115), at least one pump (103) and a first line arrangement (107) via which the pump (103) is hydraulically connected or connectable to the motor (115); characterized by a pressure limiting arrangement (119) switchable between a first maximum pressure and a second maximum pressure for limiting the pressure that can be transmitted via the first line arrangement (107).

2. Actuator (101) according to claim 1; characterized in that the pressure limiting arrangement (119) comprises a first pressure limiting valve (123a) whose opening pressure corresponds to the first maximum pressure, and a second pressure limiting valve (123b) whose opening pressure corresponds to the second maximum pressure; wherein the first pressure relief valve (123a) and the second pressure relief valve (123b) can be alternately connected to the first pipe arrangement (107).

3. Actuator (101) according to the preceding claim; characterized in that the pressure limiting arrangement (119) has a first directional control valve (125a) with which the first pressure limiting valve (123a) and the second pressure limiting valve (123b) can be alternately connected to the first line arrangement (107).

4. Actuator (101) according to one of the preceding claims; characterized by a second directional valve (109), a second piping arrangement (111), and a third piping arrangement (113); wherein the at least one pump (103) is hydraulically connected via the first line arrangement (107) to a first port of the second directional control valve (109); wherein ZF Friedrichshafen AG File 300978 Friedrichshafen 2025-01-10 a second port of the second directional valve (109) is hydraulically connected via the second line arrangement (111) to a first port of the at least one motor (115); wherein a third port of the second directional valve (109) is hydraulically connected via the third line arrangement (113) to a second port of the at least one motor (115); wherein the second directional valve (109) in a first switching position hydraulically connects the first port of the second directional valve (109) to the second port of the second directional valve (109); and wherein The second directional valve (109) in a second switching position connects the first port of the second directional valve (109) hydraulically to the third port of the second directional valve (109).

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