A hydraulic control system

Abstract

A system for controlling the pressure of a control fluid provided to a hydraulically operated pilot input unit, the system comprising: a hydraulically operated pilot input unit for controlling the movement of at least one hydraulic service, wherein the hydraulically operated pilot input unit is operable upon receipt of a control fluid; a pilot pressure pump configured to pump the control fluid from a tank to the hydraulically operated pilot input unit via a fluid channel; and a proportional control valve located within the fluid channel and being moveable from and between a fully open position, at least one partially open position, and a fully closed position to regulate the pressure of the control fluid provided to the hydraulically operated pilot input unit.

Description

[0001] A HYDRAULIC CONTROL SYSTEM

[0002] FIELD OF THE INVENTION

[0003] The present invention relates to improvements in or relating to a hydraulic control system and, more specifically, to a system for controlling the pressure of a control fluid provided to a hydraulically operated pilot input unit.

[0004] BACKGROUND TO THE INVENTION

[0005] Many hydraulically actuated systems comprise safety mechanisms configured to bring the system to a stop. However, such safety mechanisms are often very abrupt, which can lead to risks and dangers associated with the stoppage of the system. Moreover, hydraulically actuated systems typically comprise a plurality of hydraulic services, each having a separate safety mechanism. The use of multiple safety mechanisms increases the cost and complexity of the system, while also increasing the risk associated with an operable hydraulic service causing harm or damage even when other hydraulic services within the system have been stopped.

[0006] It is against this background that the present invention has arisen.

[0007] SUMMARY OF THE INVENTION

[0008] According to the present invention there is provided a system for controlling the pressure of a control fluid provided to a hydraulically operated pilot input unit, the system comprising: a hydraulically operated pilot input unit for controlling the movement of at least one hydraulic service, wherein the hydraulically operated pilot input unit is operable upon receipt of a control fluid; a pilot pressure pump configured to pump the control fluid from a tank to the hydraulically operated pilot input unit via a fluid channel; and a proportional control valve located within the fluid channel and being moveable from and between a fully open position, at least one partially open position, and a fully closed position to regulate the pressure of the control fluid provided to the hydraulically operated pilot input unit.

[0009] The use of a proportional control valve, which may also be called a modulating control valve, enables the pressure of the control fluid provided to the hydraulically operated pilot input unit to be varied from and between a maximum and minimum pressure. The proportional control valve can, therefore, be used to bring the hydraulically operated pilot input unit, and all the associated hydraulic services, to a controlled stop simultaneously and at a desired rate. This capability, which is not present in traditional hydraulic systems, is particularly beneficial in an emergency, and is crucial for applications requiring precise control over machinery operations, ensuring both efficiency and safety.

[0010] The hydraulically operated pilot input unit may control the movement of the at least one hydraulic service by controlling the flow of a working fluid provided thereto. The hydraulically operated pilot input unit may comprise one or more travel lever and / or joystick manipulator. The travel lever(s) and / or joystick manipulator(s) may be hydraulically operated. The hydraulically operated pilot input unit may be located within the cab of construction machinery.

[0011] The pilot pressure pump may be a variable pump. More specifically, the pump may be a variable displacement pump. The pilot pressure pump may be configured to pump the control fluid within the fluid channel at a pressure of up to 100 bar, 50 bar, 40 bar, or more specifically, 38 bar. The control fluid may be configured to flow from the tank to the hydraulically operated pilot input via the pump. As such, the pump may be in fluid communication with the fluid channel.

[0012] The fluid channel may be a conduit. The fluid channel may be a plurality of separate fluid channels connected together. There may be a network of fluid channels. The fluid channel, or network thereof, may comprise a filter. The filter may be configured to filter the control fluid entering and / or exiting the tank.

[0013] The system may be a dead-headed system. As such, an increase in flow rate may cause a decrease in pressure and vice versa. Therefore, the proportional control valve may regulate the pressure and / or flow rate of the control fluid provided to the hydraulically operated pilot input unit. The control fluid may be a hydraulic fluid.

[0014] The proportional control valve may be electronically controllable. The system may comprise an electronic control unit configured to move the proportional control valve from and between the fully open, partially open, and fully closed position.

[0015] An electronically controllable proportional control valve enables the pressure of the control fluid provided to the pilot input unit to be selected based on a dynamic set point, which, in turn, enables dynamic control of each of hydraulic service. The electronic control unit may be configured to automatically move the proportional control valve in response to an event. The event may be the receipt of a signal. The signal may be generated by a processor, or a risk detection unit. As such, the event may be a risk. Alternatively, or in addition, the proportional control valve may be manually controllable. For example, the proportional control valve may comprise a manual override configured to move the valve from and between its fully open position, at least one partially open position, and fully closed position. The manual override may be a screw, handle, or lever, for example.

[0016] When in the fully open position, the proportional control valve may allow the control fluid to flow from the tank (or, more specifically, the pump) to the hydraulically operated pilot input unit at a nominal pressure. When in the fully closed position, the proportional control valve may prevent the control fluid from flowing from the tank (or, more specifically, the pump) to the hydraulically operated pilot input unit. When in a partially open position, the proportional control valve may allow the control fluid to flow from the tank (or, more specifically, the pump) to the hydraulically operated pilot input unit at a pressure below the nominal pressure. The nominal pressure may be up to 100 bar, 50 bar, or 40 bar. For example, the nominal pressure may be 38 bar.

[0017] The proportion control valve may comprise a plurality of partially open positions. More specifically, the proportion control valve may comprise an infinite number of partially open positions. This enables the proportional control valve to precisely regulate the pressure of the control fluid provided to the hydraulically operated pilot input unit. For example, when in the fully open position, the proportional control valve may be 100% open. When in the fully closed position, the proportional control valve may be 0% open. When in a partially open position, the proportional control valve may between 0% and 100% open. For example, in one partially open position, the proportional control valve may be 50% open. Although, any percentage may be used, and to any number of decimal points.

[0018] It should be noted that, in the context of this application, 'fully open' does not necessarily mean that the fluid channel is completely unrestricted, although in some embodiments that may be the case. Instead, 'fully open' means that the valve is within its most opened state. Similarly, 'fully closed' means that's the valve is within its most closed state.

[0019] The proportional control valve may comprise a proportional control valve inlet configured to receive control fluid from the tank (or, more specifically, the pump). The proportional control valve may comprise a pilot input unit outlet configured to convey control fluid to the pilot input unit. The proportional control valve may comprise a tank outlet configured to convey control fluid to the tank.

[0020] When in the fully open position, the proportional control valve may direct all control fluid received from the proportional control valve inlet through the pilot input unit outlet. When in the fully closed position, the proportional control valve may direct all control fluid received from the proportional control valve inlet to the tank outlet. When in a partially open position, the proportional control valve may direct some of the control fluid received from the proportional control valve inlet through each of the pilot input unit outlet and the tank outlet.

[0021] Directing all control fluid to the tank via the tank outlet may be used to inactivate the pilot input unit, thus bring the associated hydraulic services to a stop, as the hydraulic pressure within the fluid channel leading to the pilot input unit is reduced to zero. Moreover, controlling the transition from the fully open position to the fully closed position enables the pilot input unit, thus hydraulic service(s), to be brought to a stop slowly and safely.

[0022] The system may comprise a pilot isolation valve located within the fluid channel. The pilot isolation valve may be moveable from a fully open position to a fully closed position to prevent the control fluid from flowing from the tank to the hydraulically operated pilot input unit. The pilot isolation valve may also be moveable from the fully closed position to the fully open position to allow the control fluid to flow from the tank (or, more specifically, the pump) to the hydraulically operated pilot input unit.

[0023] The pilot isolation valve may be held within: a fully open position configured to allow the control fluid to flow from the tank to the hydraulically operated pilot input unit at a nominal pressure; or a fully closed position configured to prevent the control fluid from flowing from the tank to the hydraulically operated pilot input unit. The pilot isolation valve may not be held within a partially open position. As such, the pilot isolation valve may not regulate the pressure of the control fluid provided to the hydraulically operated pilot input unit. The pilot isolation valve may, therefore, also be called a shutoff valve. Again, in each of the aforementioned scenarios, the pilot isolation valve may more specifically control the flow of the control fluid between the pump and the hydraulically operated pilot input unit.

[0024] The pilot isolation valve may be hydraulically controlled. For example, the pilot isolation valve may be hydraulically controlled via the hydraulically controlled pilot input unit. Alternatively, or in addition, the pilot isolation valve may be electronically controlled. For example, the pilot isolation valve may be electronically controlled via the hydraulically controlled pilot input unit. As such, the hydraulically controlled pilot input unit may also comprise electronic controls. Alternatively, or in addition, the pilot isolation valve may be electronically controlled via the electronic control unit.

[0025] The proportional control valve may be located between the pilot isolation valve and the hydraulically operated pilot input unit. This enables it to have a direct impact on the hydraulic services being controlled by the hydraulically operated pilot input unit. The system may comprise a pressure sensor configured to measure the pressure within the fluid channel. The proportional control valve may be configured to automatically move between its fully open position, at least one partially open position, and fully closed position based on the measured pressure. The pressure sensor therefore enables the system to self-calibrate and / or maintain a desired pressure of the control fluid.

[0026] The pressure sensor may be configured to measure the pressure within the fluid channel between the pilot isolation valve and the hydraulically operated pilot input unit. In some embodiments, there may be two or more pressure sensors configured to measure the pressure within the fluid channel between the pilot isolation valve and the hydraulically operated pilot input unit. One pressure sensor may be between the pilot isolation valve and the proportional control valve. One pressure sensor may be between the proportional control valve and the hydraulically operated pilot input unit.

[0027] The system may comprise a risk detection unit configured to automatically move the proportional control valve towards its fully closed position upon detection of a risk. For example, the risk detection unit may be configured to automatically move the proportional control valve to its partially open position or its fully closed position upon detection of a risk. The risk may be a person or object, such as a vehicle, located within a predetermined distance of an in use hydraulic service.

[0028] The risk detection unit may be configured to automatically move the proportional control valve towards its fully closed position at a controlled rate. The controlled rate may be predetermined. The controlled rate may be variable. This enables the pilot input unit, and corresponding hydraulic service(s), to be suitably slowed down and / or brought to a complete stop within a suitable time frame. This time frame may vary depending on the type of hydraulic service(s) being controlled by the pilot input unit and / or the power being provided to each hydraulic service, in use.

[0029] The proportional control valve may be electronically controlled via the risk detection unit. The risk detection unit may electronically modulate the proportional control valve to achieve highly controlled movement, particularly stoppage, of one or more hydraulic service being controlled by the pilot input unit. For example, the risk detection unit may produce a pulse width modulation (PWM) signal configured to move the proportional control valve between the fully open, partially open and / or fully closed positions.

[0030] The risk detection unit may comprise at least one camera. The at least one camera may be configured to generate and send video data to a processor for analysis. The processor may be configured to identify a risk within the video data and generate a signal corresponding thereto. The signal may be configured to automatically move the proportional control valve towards its fully closed position. The processor may be the electronic control unit. The signal generated by the processor may be the PWM signal. The use of a camera and processor enables risks, such as people and / or vehicles, to be distinguished from non-risks, such as buildings and / or structures. For example, the processor may comprise image processing artificial intelligence (Al). The image processing Al may be configured to identify the risk within video data received from the at least one camera.

[0031] The risk detection unit may be configured to determine a severity of the risk. The risk detection unit may be configured to move the proportional control valve towards its fully closed position by an amount that is based upon the determined severity.

[0032] The severity of the risk may be detected using the image processing Al. For example, a certain entity may be classified as high risk, whereas another entity may be classified as low risk. Alternatively, or in addition, the severity of the risk may be determined based, at least in part, on the distance between the detected risk and a hydraulic service being controlled by the system. The distance may be determined using the processor and / or image processing Al.

[0033] The amount by which the proportional control valve moves in response to the detected risk may be a percentage of the distance between its fully open and fully closed position. As such, the risk detection unit may be configured to move the proportional control valve a percentage amount towards its fully closed position, wherein the percentage amount is based upon the determined severity. The percentage amount may be up to 10%, 25%, 50%, 75%, 90% or 100%. For example, a risk having a low severity may cause the risk detection unit to move the proportional control valve up to 50% towards its fully closed position. Conversely, a risk having a high severity may cause the risk detection unit to move the proportional control valve 100% towards its fully closed position. Doing so would bring the hydraulically operated pilot input unit, and all the associated hydraulic services, to a complete stop. The processor may be used to determine the severity of the risk.

[0034] Alternatively, or in addition, the risk detection unit may be configured to move the proportional control valve towards its fully closed position at a rate that is based upon the determined severity. For example, a risk having a low severity may cause the risk detection unit to move the proportional control valve towards its fully closed position at a first rate. Conversely, a risk having a high severity may cause the risk detection unit to move the proportional control valve towards its fully closed position at a second rate, wherein the second rate is faster than the first rate.

[0035] The system may comprise an override button configured to move the proportional control valve from and between its fully open position, at least one partially open position, and fully closed position. This enables temporary deactivation of the proportional control valve and / or an additional fail-safe mechanism for bringing the system to a stop.

[0036] The override button may be an electronic button. The electronica button may be configured to generate an electronic signal configured to move the proportional control valve. Alternatively, the override button may be a manual override button. The manual override button may be physically connected to the proportional control valve. The manual override button may be configured to move the proportional control valve upon actuation thereof.

[0037] There is also provided machinery or equipment comprising the system according to any preceding claim. The machinery may be a vehicle. The vehicle may be a construction vehicle, such as an excavator. The machinery or equipment may be construction machinery or construction equipment.

[0038] The machinery or equipment may comprise the at least one hydraulic service. For example, the machinery or equipment may comprise a plurality of hydraulic services. At least one hydraulic service may comprise an actuator. At least one hydraulic service may comprise: boom in; boom out; bucket open (or bucket curl); bucket close (or bucket dump); dipper in; dipper out; slue left (swing left); slue right (swing right); left tracking forward; left tracking backward; right tracking forward; right tracking backward. The hydraulically operated pilot input unit may control the movement of each (i.e., all) hydraulic service by controlling the flow of a working fluid provided thereto.

[0039] Each hydraulic service may be operable upon receipt of a working fluid. The machinery or equipment may comprise a hydraulic service pressure pump configured to pump the working fluid from a reservoir to the hydraulic service via a fluid pipe.

[0040] Each hydraulic service may comprise a corresponding service valve. The service valve may be located within the fluid pipe. Each service valve may be configured to control the pressure of the working fluid provided to the corresponding hydraulic service. The hydraulically operated pilot input unit may be configured to adjust each service valve to control the pressure of the working fluid provided to the corresponding hydraulic service.

[0041] The invention will now be further and more particularly described, by way of example only, with reference to the accompanying drawing.

[0042] FIGURES

[0043] Figure 1 shows a system for controlling the pressure of a control fluid provided to a hydraulically operated pilot input unit. DETAILED DESCRIPTION

[0044] Figure 1 shows a system for controlling the pressure of a control fluid provided to a hydraulically operated pilot input unit. The system 100 comprises a hydraulically operated pilot input unit 110 for controlling the movement of at least one hydraulic service 200i, 2002, 200n. The hydraulically operated pilot input unit 110 is operable upon receipt of a control fluid. A pilot pressure pump 120 is configured to pump the control fluid from a tank 130 to the hydraulically operated pilot input unit 110 via a fluid channel 140. The system further comprises a proportional control valve 150 located within the fluid channel 140. The proportional control valve 150 is moveable from and between a fully open position, at least one partially open position, and a fully closed position to regulate the pressure of the control fluid provided to the hydraulically operated pilot input unit 110.

[0045] The proportional control valve 150 may be electronically controllable. As such, the system may comprise an electronic control unit (not shown in the accompanying drawings) configured to move the proportional control valve 150 from and between the fully open, partially open, and fully closed position.

[0046] The proportional control valve comprises a proportional control valve inlet 151 configured to receive control fluid from the tank 130; a pilot input unit outlet 152 configured to convey control fluid to the pilot input unit 110; and a tank outlet 153 configured to convey control fluid to the tank, 130.

[0047] When in its fully open position, the proportional control valve 150 directs all control fluid received from the proportional control valve inlet 151 through the pilot input unit outlet 152. When in its fully closed position, the proportional control valve 150 directs all control fluid received from the proportional control valve inlet 151 to the tank outlet 153. When in its at least one partially open position, the proportional control valve 150 directs some of the control fluid received from the proportional control valve inlet 151 through each of the pilot input unit outlet 152 and the tank outlet 153.

[0048] The system may further comprise a pilot isolation valve 160 located within the fluid channel 140. The pilot isolation valve 160 may be moveable from a fully open position to a fully closed position to prevent the control fluid from flowing from the tank 130 to the hydraulically operated pilot input unit 110. More specifically, the pilot isolation valve 160 may be moveable from a fully open position to a fully closed position to prevent the control fluid from flowing from the pump 120 to the hydraulically operated pilot input unit llO.As shown in Figure 1, the proportional control valve 150 may be located between the pilot isolation valve 160 and the hydraulically operated pilot input unit 110.

[0049] The system may comprise a pressure sensor 170. The pressure sensor 170 may be configured to measure the pressure within the fluid channel 140 between the pilot isolation valve 160 and the hydraulically operated pilot input unit 110. More specifically, the pressure sensor 170 may be configured to measure the pressure within the fluid channel 140 between the proportional control valve 150 and the hydraulically operated pilot input unit 110. The proportional control valve 150 may be configured to automatically move between its fully open position, its at least one partially open position, and its fully closed position based on the measured pressure.

[0050] The system may further comprise a risk detection unit 180 configured to automatically move the proportional control valve towards its fully closed position upon detection of a risk. The risk detection unit may comprise at least one camera 181 configured to generate and send video data to a processor for analysis. The processor may be located within the risk detection unit 180. The processor may be configured to identify a risk within the video data and generate a signal corresponding thereto. The signal may be configured to automatically move the proportional control valve 150 towards its fully closed position upon detection of a risk.

[0051] In some embodiments, the risk detection unit 180 is configured to determine a severity of the risk. For example, the processor may determine the severity of the risk. The risk detection unit 180 may be configured to move the proportional control valve 150 towards its fully closed position by an amount that is based upon the determined severity.

[0052] The risk detection unit 180, or processor therein, may also comprise the electronic control unit configured to move the proportional control valve from and between the fully open, partially open, and fully closed position.

[0053] Various further aspects and embodiments of the present invention will be apparent to those skilled in the art in view of the present disclosure, "and / or" where used herein is to be taken as specific disclosure of each of the two specified features or components with or without the other. For example, "A and / or B" is to be taken as specific disclosure of each of (i) A, (ii) B and (iii) A and B, just as if each is set out individually herein. Unless context dictates otherwise, the descriptions and definitions of the features set out above are not limited to any particular aspect or embodiment of the invention and apply equally to all aspects and embodiments that are described. It will further be appreciated by those skilled in the art that although the invention has been described by way of example with reference to several embodiments, it is not limited to the disclosed embodiments and that alternative embodiments could be constructed without departing from the scope of the invention as defined in the appended claims.

Claims

CLAIMS1. A system for controlling the pressure of a control fluid provided to a hydraulically operated pilot input unit, the system comprising: a hydraulically operated pilot input unit for controlling the movement of at least one hydraulic service, wherein the hydraulically operated pilot input unit is operable upon receipt of a control fluid; a pilot pressure pump configured to pump the control fluid from a tank to the hydraulically operated pilot input unit via a fluid channel; and a proportional control valve located within the fluid channel and being moveable from and between a fully open position, at least one partially open position, and a fully closed position to regulate the pressure of the control fluid provided to the hydraulically operated pilot input unit.

2. The system according to any preceding claim, wherein the proportional control valve is electronically controllable, and wherein the system comprises an electronic control unit configured to move the proportional control valve from and between the fully open, partially open, and fully closed position.

3. The system according to any preceding claim, wherein: when in the fully open position, the proportional control valve is configured to allow the control fluid to flow from the tank to the hydraulically operated pilot input unit at a nominal pressure; when in the fully closed position, the proportional control valve is configured to prevent the control fluid from flowing from the tank to the hydraulically operated pilot input unit; andwhen in the at least one partially open position, the proportional control valve is configured to allow the control fluid to flow from the tank to the hydraulically operated pilot input unit at a pressure below the nominal pressure.

4. The system according to any preceding claim, wherein the proportional control valve comprises: a proportional control valve inlet configured to receive control fluid from the tank; a pilot input unit outlet configured to convey control fluid to the pilot input unit; and a tank outlet configured to convey control fluid to the tank, wherein, when in the fully open position, the proportional control valve directs all control fluid received from the proportional control valve inlet through the pilot input unit outlet; when in the fully closed position, the proportional control valve directs all control fluid received from the proportional control valve inlet to the tank outlet; and, when in the at least one partially open position, the proportional control valve directs some of the control fluid received from the proportional control valve inlet through each of the pilot input unit outlet and the tank outlet.

5. The system according to any preceding claim, further comprising a pilot isolation valve located within the fluid channel and being moveable from a fully open position to a fully closed position to prevent the control fluid from flowing from the tank to the hydraulically operated pilot input unit.

6. The system according to claim 5, wherein the proportional control valve is located between the pilot isolation valve and the hydraulically operated pilot input unit.

7. The system according to any preceding claim, further comprising a pressure sensor configured to measure the pressure within the fluid channel, wherein the proportional control valve is configured to automatically move between its fully open position, at least one partially open position, and fully closed position based on the measured pressure.

8. The system according to any preceding claim, further comprising a risk detection unit configured to automatically move the proportional control valve towards its fully closed position upon detection of a risk.

9. The system according to claim 8, wherein the risk detection unit comprises at least one camera configured to generate and send video data to a processor for analysis, wherein the processor is configured to identify a risk within the video data and generate a signal corresponding thereto, and wherein the signal is configured to automatically move the proportional control valve towards its fully closed position.

10. The system according to claim 8 or 9, wherein the risk detection unit is configured to determine a severity of the risk and move the proportional control valve towards its fully closed position by an amount that is based upon the determined severity.

11. The system according to any preceding claim, further comprising an override button configured to move the proportional control valve from and between its fully open position, at least one partially open position, and fully closed position.

12. Machinery or equipment comprising the system according to any preceding claim.

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