A hydraulic control system for a helicopter transmission

Abstract

The present application relates to a kind of hydraulic control systems for helicopter transmission, the helicopter transmission includes input shaft, clutch is arranged between the input shaft and engine, the clutch can be separated or engaged by the hydraulic pressure provided by the hydraulic control system, the hydraulic control system includes: oil supply oil path, one end of the oil supply oil path is connected to oil tank, the other end is connected to main oil path;Main oil path, main oil pressure control valve is arranged on the main oil path;Pilot oil path, one end of the pilot oil path is connected to the main oil path, and pilot control valve is arranged in the pilot oil path, the other end of the pilot oil path is connected to one port of clutch control valve, clutch control oil path, one end of the clutch control oil path is connected to the main oil path, and clutch control valve is arranged in the clutch control oil path.

Description

Technical Field

[0001] This invention belongs to the field of hydraulic technology, and specifically relates to a hydraulic control system for helicopter transmission devices. Background Technology

[0002] Currently, centrifugal clutches are commonly used between helicopter engines and gearboxes, while the hydraulic system relies on only one mechanical pump to cool and lubricate the bearings and other lubrication points of the entire aircraft. The engagement of a centrifugal clutch is dependent on the input speed; that is, the clutch can only engage when a certain input speed is reached, resulting in a simplistic control method. Furthermore, due to its high-speed rotation, achieving adequate cooling and lubrication is difficult, easily leading to component burn-out. The direct-supply cooling and lubrication system via a mechanical pump has low controllability, prone to insufficient cooling and lubrication at low speeds and over-lubrication at high speeds. Summary of the Invention

[0003] Based on the inventor's research and practical experience in this field, the following improved technical solutions are proposed.

[0004] A hydraulic control system for a helicopter transmission includes an input shaft, a clutch is disposed between the input shaft and an engine, the clutch being disengaged or engaged by hydraulic pressure provided by the hydraulic control system, the hydraulic control system comprising:

[0005] The oil supply line is connected at one end to the oil tank and at the other end to the main oil line.

[0006] Main oil circuit, wherein a main oil pressure control valve is installed on the main oil circuit;

[0007] A pilot oil circuit is provided, one end of which is connected to the main oil circuit and a pilot control valve is installed in the pilot oil circuit. The other end of the pilot oil circuit is connected to a port of the clutch control valve.

[0008] A clutch control oil circuit, one end of which is connected to the main oil circuit, and a clutch control valve is disposed in the clutch control oil circuit.

[0009] As a feasible preferred embodiment of the present invention, the oil supply circuit includes a first oil supply branch and a second oil supply branch connected in parallel, wherein a mechanical pump is provided in the first oil supply branch and an electric pump is provided in the second oil supply branch.

[0010] As a feasible preferred embodiment of the present invention, a first suction filter is provided between the mechanical pump and the oil tank in the first oil supply branch; and / or a second suction filter is provided between the electric pump and the oil tank in the second oil supply branch.

[0011] As a feasible preferred embodiment of the present invention, a first check valve is provided after the mechanical pump; and / or a second check valve is provided after the electric pump.

[0012] As a feasible preferred embodiment of the present invention, a main oil pressure safety valve is also provided in the main oil circuit.

[0013] As a feasible preferred embodiment of the present invention, a lubrication and cooling branch is provided downstream of the main oil pressure control valve, and the lubrication and cooling branch is connected to the element to be lubricated.

[0014] As a feasible preferred embodiment of the present invention, a lubrication and cooling branch safety valve is provided in the lubrication and cooling branch.

[0015] As a feasible preferred embodiment of the present invention, a lubrication and cooling branch pressure sensor is provided in the lubrication oil circuit.

[0016] As a feasible preferred embodiment of the present invention, a buffer is also provided in the pilot oil circuit.

[0017] As a feasible preferred embodiment of the present invention, a pressure sensor is also provided in the clutch control oil circuit.

[0018] This invention provides a hydraulic control system for a helicopter transmission, comprising an oil supply subsystem, a main oil pressure control subsystem, a clutch control subsystem, and a lubrication and cooling subsystem. The oil supply subsystem includes a mechanical pump and an electric pump. When the helicopter is first started, the electric pump provides the system pressure and flow to engage the clutch and transmit power. During warm-up or acceleration, before the helicopter's engine reaches its normal operating speed, both the mechanical and electric pumps operate together. Once the helicopter reaches its normal operating speed, the mechanical pump operates independently. Additionally, if insufficient system flow or pressure occurs due to wear or other abnormal conditions, the electric pump intervenes to supplement the required flow.

[0019] Other features and advantages of the present invention will be described in detail below with reference to the accompanying drawings. Attached Figure Description

[0020] Exemplary embodiments of the present invention are described with reference to the accompanying drawings, wherein:

[0021] Figure 1 A schematic diagram of the hydraulic control system for a helicopter transmission device according to the present invention is shown. Detailed Implementation

[0022] Embodiments of the present invention are described below with reference to the accompanying drawings. In the following description, numerous specific details are set forth to enable those skilled in the art to more fully understand and implement the invention. However, it will be apparent to those skilled in the art that implementations of the invention may not include some of these specific details. Furthermore, it should be understood that the invention is not limited to the specific embodiments described. Rather, the invention can be conceived to be practiced with any combination of the features and elements described below, regardless of whether they relate to different embodiments. Therefore, the following aspects, features, embodiments, and advantages are for illustrative purposes only and should not be construed as features or limitations of the claims unless expressly set forth in the claims.

[0023] The descriptions of orientation used in the following description, such as “upper,” “lower,” “inner,” “outer,” “radial,” and “axial,” are merely for convenience of description and are not intended to limit the technical solution of the invention unless explicitly stated otherwise. Furthermore, the terms “first,” “second,” and other similar terms used below to describe the elements of this application are only used to distinguish individual elements and are not intended to limit the nature, sequence, order, or number of these elements.

[0024] Figure 1 A schematic diagram of the hydraulic control system for a helicopter transmission device according to the present invention is shown. Figure 1 As shown, the hydraulic control system includes an oil tank 18, which stores the hydraulic fluid required for the operation of the entire hydraulic system. The hydraulic control system has two pipelines connected to the oil tank 18: a first oil supply branch and a second oil supply branch. A mechanical pump 2 is installed in the first oil supply branch, and an electric pump 5 is installed in the second oil supply branch. In the first oil supply branch, between the mechanical pump 2 and the oil tank 18, a first suction filter 1 is also installed to filter impurities from the hydraulic fluid. A first check valve 3 is installed after the mechanical pump to prevent backflow of hydraulic fluid from the downstream pipeline into the mechanical pump.

[0025] Similarly, in the second oil supply branch, a second suction filter 4 is installed between the electric pump 5 and the oil tank 18 to filter impurities in the oil. After the electric pump 5, a second check valve 6 is installed to prevent oil in the downstream pipeline from flowing back into the electric pump 5.

[0026] Subsequently, the first and second oil supply branches merge into the main oil circuit. In other words, the first and second oil supply branches are connected in parallel, allowing the system to be supplied with oil by a mechanical pump alone, an electric pump alone, or both together. This ensures that the oil supply meets the system's needs.

[0027] This invention defines the operating ranges of the electronic pump and the mechanical pump according to different working conditions, allowing them to work simultaneously or independently. The cooling and lubrication system is highly controllable, ensuring sufficient lubrication of the heat-generating components of the reducer and avoiding over-lubrication. It also improves the working efficiency of the mechanical and electronic pumps, as well as the efficiency of the entire oil supply subsystem, reducing unnecessary flow waste and power consumption loss.

[0028] Specifically, a mechanical pump can be driven by a single driven gear, while an electric pump can be driven by a control unit.

[0029] A main oil circuit pressure sensor 7 is installed in the main oil circuit to monitor the pressure. A main oil pressure safety valve 8, for example, a mechanical valve, is also installed in the main oil circuit. A main oil pressure control valve 9 is also installed in the main oil circuit, which can be located downstream of the main oil pressure safety valve 8. This circuit is a high-pressure oil circuit. The main oil pressure control valve 8 and the main oil pressure control valve 9 work together to control the pressure in the main oil circuit. The main oil pressure control valve 9 can be a solenoid valve, and the supply current is controlled by a control unit to control the pressure.

[0030] Two branches are drawn from the high-pressure oil circuit of the main oil circuit: a pilot oil circuit and a clutch control branch. Specifically, a pressure reducing valve 10 is installed in the pilot oil circuit. The pressure reducing valve 10 is, for example, a mechanical valve, which maintains the output pressure at the rear end of the valve core at a target pressure lower than the main oil pressure by a preset value. A pilot control valve 11 is then installed in this branch. The pilot oil circuit is then connected to one end of the clutch control valve 13. The pilot control valve 11 can also be a solenoid valve, which controls the supply current through a control unit, thereby controlling the output pressure. The clutch control valve 13 is a mechanical valve, which works in conjunction with the pilot control valve 11 to control the operating pressure of the hydraulic oil supplied to the clutch.

[0031] In this branch, a buffer 12 is also provided. When the input flow pulsates or the main oil pressure fluctuates, the buffer 12 absorbs the fluctuations in the output pressure of the pilot control valve, thereby keeping the clutch pressure output by the clutch control valve stable.

[0032] A branch line is also drawn from the high-pressure oil circuit and connected to the clutch control valve 13, thus forming a clutch control branch line. A pressure sensor 14 is installed in this branch line to measure the pressure within it. This branch line is then connected to the clutch 15 to supply it with hydraulic oil.

[0033] Downstream of the main oil pressure control valve 9, a lubrication and cooling branch is formed. This branch is also equipped with a lubrication and cooling branch pressure sensor 19 to monitor the pressure in this branch. A lubrication and cooling branch 16 is also provided on this branch. The oil in this branch is supplied to the various components 17 of the reducer for lubrication and cooling.

[0034] The hydraulic control system of this invention is used for controlling the clutch of a helicopter. As an example, a transmission device is provided between the helicopter's rotor and engine. The clutch can be located between the helicopter's engine and the transmission device. The transmission device may include multiple gear elements and shafts for supporting the gear elements. For example, the transmission device can be a fixed-axis gear system, or a planetary gear system, or a combination of a fixed-axis gear system and a planetary gear system. To ensure engine starting and, in emergency situations, power connection or disconnection with the rotor, the clutch is located in the transmission path between the power source and the input shaft of the transmission device. The clutch can be a wet clutch, particularly a wet multi-plate clutch. Further, the clutch can be a normally closed wet multi-plate clutch or a normally open wet multi-plate clutch.

[0035] The hydraulic system of this invention has a pressure sensor connected to the main oil circuit, the clutch control oil circuit, and the lubrication and cooling oil circuit to monitor the pressure of each oil circuit, and achieves precise control of the actuator through real-time feedback.

[0036] As described above, this invention provides a hydraulic control system for a helicopter transmission device. This system mainly consists of four parts: an oil supply subsystem, a main oil pressure control subsystem, a clutch control subsystem, and a lubrication and cooling control subsystem. The oil supply subsystem comprises a mechanical pump and an electric pump connected in parallel, providing pressure and sufficient flow to the system. In the main oil pressure control subsystem, after the oil pump exits, it passes through the main oil pressure regulating valve. The valve's cross-sectional difference and spring force control the main oil circuit pressure to a preset pressure. When the main oil pressure is too high, it will release pressure from the main oil pressure safety valve 8, ensuring the safety of the entire hydraulic control system.

[0037] In the clutch control subsystem, the main oil pressure is stabilized at the target pressure after passing through the pressure reducing valve, providing a stable input pressure for the pilot control valve; the pilot control magnet provides pilot oil pressure to control the valve core displacement of the clutch control valve, thereby controlling the clutch pressure.

[0038] In the lubrication subsystem, oil flows from the overflow end of the main oil pressure control valve to each throttle orifice to lubricate the corresponding heating elements, and finally returns to the oil tank. However, when the flow rate of the lubrication subsystem is too high and reaches the opening pressure of the lubrication safety valve, the oil will be discharged from the valve to prevent over-lubrication and affect the transmission efficiency.

[0039] The foregoing description is merely an exemplary embodiment relating to the spirit and principles of the present invention. Those skilled in the art will understand that various changes can be made to the described examples without departing from the spirit and principles, and such changes and their various equivalents are contemplated by the inventors and fall within the scope defined by the claims of the present invention.

Claims

1. A hydraulic control system for a helicopter transmission, the helicopter transmission including an input shaft, a clutch disposed between the input shaft and an engine, the clutch being disengaged or engaged by hydraulic pressure provided by the hydraulic control system, characterized in that, The hydraulic control system includes: The oil supply line is connected at one end to the oil tank (18) and at the other end to the main oil line; Main oil circuit, wherein a main oil pressure control valve (9) is provided on the main oil circuit; A pilot oil circuit is provided, one end of which is connected to the main oil circuit and a pilot control valve (11) is provided in the pilot oil circuit. The other end of the pilot oil circuit is connected to a port of the clutch control valve (13). A clutch control oil circuit, one end of which is connected to the main oil circuit, and a clutch control valve (13) is disposed in the clutch control oil circuit. The fuel supply circuit includes a first fuel supply branch and a second fuel supply branch connected in parallel. A mechanical pump (2) is installed in the first fuel supply branch, and an electric pump (5) is installed in the second fuel supply branch. When the helicopter is first started, the electric pump provides the system pressure and flow to engage the clutch and transmit power. During the warm-up or acceleration phase, the helicopter engine has not reached its normal operating speed, and the mechanical pump and the electric pump work together. When the helicopter reaches its normal operating speed, the mechanical pump works independently. When the system flow or pressure is insufficient due to abnormal conditions, the electric pump intervenes to supplement the required flow.

2. The hydraulic control system for a helicopter transmission device according to claim 1, characterized in that, In the first oil supply branch, a first suction filter (1) is provided between the mechanical pump (2) and the oil tank (18); and / or in the second oil supply branch, a second suction filter (4) is provided between the electric pump (5) and the oil tank (18).

3. The hydraulic control system for a helicopter transmission device according to claim 2, characterized in that, A first check valve (3) is provided after the mechanical pump; and / or A second check valve (6) is provided after the electric pump (5).

4. The hydraulic control system for a helicopter transmission according to any one of claims 1-3, characterized in that, The main oil circuit is also equipped with a main oil pressure safety valve (8).

5. The hydraulic control system for a helicopter transmission according to any one of claims 1-3, characterized in that, Downstream of the main oil pressure control valve (9), a lubrication and cooling branch is provided, which is connected to the element to be lubricated.

6. The hydraulic control system for a helicopter transmission according to claim 5, characterized in that, A lubrication and cooling branch safety valve (16) is provided in the lubrication and cooling branch.

7. The hydraulic control system for a helicopter transmission according to claim 5, characterized in that, A pressure sensor (19) for the lubrication and cooling branch is installed in the lubrication circuit.

8. The hydraulic control system for a helicopter transmission according to any one of claims 1-3, characterized in that, A buffer (12) is also provided in the pilot oil circuit.

9. The hydraulic control system for a helicopter transmission according to any one of claims 1-3, characterized in that, A pressure sensor (14) is also provided in the clutch control oil circuit.

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