Actuator assembly for braking system

Abstract

An actuator assembly (10) is disclosed for generating and modulating hydraulic braking pressure. The actuator assembly (10) comprises a tank unit (20) for containing hydraulic fluid, a pump (22), a motor (42) driving the pump (22), and a valveless block unit (30) disposed between the tank unit (20) and a motor cover (40). The block unit (30) defines an internal fluid path (31) connected to an inlet port (33), a first outlet port (32), and a second outlet port (34). In use, the pump (22) draws hydraulic fluid from the tank unit (20) and delivers pressurised fluid through the inlet port (33) to one of the first and second outlet ports (32, 34) configured as an actuation port for supplying hydraulic pressure to one or more brake callipers, while a continuous minor return flow is directed to the tank unit (20) through the other of the outlet ports (32, 34) configured as a fixed-orifice return jet port. Relative diameters of the outlet ports (32, 34) determine flow resistance and pressure regulation. Braking pressure is controlled substantially solely by motor speed, without hydraulic valves or solenoids, enabling proportional pressure control, rapid pressure dissipation, and a simplified hydraulic architecture.

Description

[0001] Actuator Assembly for Braking System

[0002] Field of the Invention

[0003]

[0001] The present invention relates to an actuator for braking systems for trailers, specifically to an actuator for an Electric Over Hydraulic (EOH) braking system that removes the need for a hydraulic valve.

[0004] Background of the Invention

[0005] [2] Traditional EOH braking systems for trailers utilize a 12 or 24-volt DC electric motor connected to a hydraulic pump, hydraulic block circuit, and a hydraulic valve. The hydraulic valve is designed to control the flow of hydraulic fluid between the brake callipers and the brake fluid tank. The system operates by receiving a proportional control signal from the tow vehicle, which the hydraulic valve uses to proportionally control the braking pressure. While effective, these systems are complex and involve multiple mechanical components, leading to slower response times, higher current draw, and increased manufacturing costs.

[0006] [3] The present invention seeks to overcome or substantially ameliorate at least some of the deficiencies of the prior art, or to at least provide an alternative.

[0007] [4] It is to be understood that, if any prior art information is referred to herein, such reference does not constitute an admission that the information forms part of the common general knowledge in the art, in Australia or any other country.

[0008] Summary of the Invention

[0009] [5] In one aspect, the disclosure provides an actuator assembly comprising:

[0010] a tank unit for holding hydraulic fluid;

[0011] a block unit having an internal hydraulic path formed therein, the block unit having an inlet port, an actuation port, and a return port connected to the internal hydraulic path; a pump disposed within the tank unit for receiving hydraulic fluid from the tank unit, an outlet of the pump being fluidly connected to the inlet port of the block unit;

[0012] a motor for driving the pump;

[0013] wherein, when actuated by the motor, the pump draws hydraulic fluid from the tank unit and delivers pressurised hydraulic fluid via the actuation port to one or more braking elements and a continuous portion of hydraulic fluid returns to the tank unit through the return port.[6] In a preferred embodiment, the internal hydraulic path defines a single path bidirectional architecture such that pressurisation and depressurisation occur through the same internal hydraulic path.

[0014] [7] In another preferred embodiment, the return port has a smaller effective flow area than the actuation port.

[0015] [8] In another preferred embodiment, the return port is formed as a fixed geometry orifice.

[0016] [9] In another preferred embodiment, braking pressure delivered via the actuation port is regulated by varying a rotational speed of the motor.

[0017]

[0010] In another preferred embodiment, the return port is configured to govern a maximum attainable braking pressure for a given motor speed by controlling the proportion of hydraulic fluid returned to the tank unit during pressurisation.

[0018]

[0011] In another preferred embodiment, the return port is configured to govern a rate of pressure dissipation upon reduction or cessation of motor speed.

[0019]

[0012] In another preferred embodiment, the block unit comprises a first outlet port and a second outlet port, one of which defines the actuation port and the other of which defines the return port.

[0020]

[0013] In another preferred embodiment, pressurised hydraulic fluid is delivered to one or more brake callipers through the first outlet port and hydraulic fluid is returned to the tank unit through the second outlet port.

[0021]

[0014] In another preferred embodiment, the pump is disposed within the tank unit such that a pump inlet is submerged in hydraulic fluid during operation.

[0022]

[0015] In another preferred embodiment, the block unit forms a sealed wall of the tank unit.

[0023]

[0016] In another preferred embodiment, the block unit is free of any hydraulic valve, proportional solenoid, or switching mechanism for regulating braking pressure.

[0024]

[0017] In another preferred embodiment, the actuator assembly further comprises an electronic control unit configured to receive a braking demand signal and to control the motor speed in response to the braking demand signal.

[0025]

[0018] In another preferred embodiment, the pump is mounted to and mechanically coupled to the block unit.

[0026]

[0019] In another preferred embodiment, the motor is disposed on an opposite side of the block unit from the pump and is coupled to the pump via an axle extending through the block unit.

[0020] In another preferred embodiment, the block unit is formed as a solid block having a pump side face and a motor side face, and the internal hydraulic path comprises at least one internal channel formed within the block unit.

[0027]

[0021] In another preferred embodiment, the internal channel comprises a vertical channel and a horizontal channel intersecting at an intersection point.

[0028]

[0022] In another preferred embodiment, the vertical channel extends between the inlet port and one of the actuation port or return port formed at a distal end of the vertical channel.

[0029]

[0023] In another preferred embodiment, the horizontal channel extends between the intersection point and the other of the actuation port or return port formed at a distal end of the horizontal channel.

[0030]

[0024] In another preferred embodiment, the tank unit comprises an end wall and a plurality of side walls defining a hollow tank chamber, and the block unit closes an open side of the tank unit.

[0031]

[0025] In another preferred embodiment, the actuation port is fluidly connected to one or more brake calliper lines for actuating brake callipers.

[0032]

[0026] In another preferred embodiment, the tank unit includes an internal hydraulic line connected to the actuation port, allowing an external brake calliper line to be connected to the actuator assembly.

[0033]

[0027] In another preferred embodiment, the return port opens directly into the tank chamber such that the return port remains submerged in hydraulic fluid during operation.

[0034]

[0028] In another preferred embodiment, the internal channels are formed as blind drilled bores sealed at their openings.

[0035]

[0029] In another preferred embodiment, the block unit is machined from aluminium or an aluminium alloy.

[0036]

[0030] In another preferred embodiment, the actuator assembly further comprises a removable cartridge attached to the return port of the block unit.

[0037]

[0031] In another preferred embodiment, the cartridge includes a hollow cartridge body having an inlet end, an outlet end, and an internal flow passage extending between the inlet end and the outlet end.

[0038]

[0032] In another preferred embodiment, the cartridge body includes a flow restricting orifice disposed in the internal flow passage.

[0039]

[0033] In another preferred embodiment, the cartridge further includes a filtration element disposed upstream of the orifice within the internal flow passage.

[0034] In another preferred embodiment, the cartridge is threadedly engaged with the return port of the block unit.

[0040]

[0035] In another preferred embodiment, the cartridge includes a keying feature configured to prevent incorrect orientation during installation.

[0041]

[0036] In another preferred embodiment, the actuator assembly further comprises a pressure sensor mounted to the block unit and configured to sense pressure within the internal hydraulic path.

[0042]

[0037] In another preferred embodiment, the pressure sensor is fluidly connected to the internal hydraulic path via a fourth port extending from a motor side face of the block unit to the internal hydraulic path.

[0043]

[0038] In an alternative embodiment, the second outlet port is disposed along a vertical channel of the internal hydraulic path below the inlet port.

[0044]

[0039] In another preferred embodiment, the second outlet port and the first outlet port are arranged along a common hydraulic flow path within the internal hydraulic path such that hydraulic fluid flows sequentially past the second outlet port and then to the first outlet port.

[0045]

[0040] In another aspect, the disclosure provides a method of generating and regulating hydraulic braking pressure, the method comprising:

[0046] drawing hydraulic fluid from a tank unit into a pump;

[0047] driving the pump using a motor to deliver hydraulic fluid into an internal hydraulic path formed in a block unit;

[0048] delivering pressurised hydraulic fluid from the internal hydraulic path to one or more braking elements through an actuation port formed in the block unit; and continuously returning a portion of the hydraulic fluid from the internal hydraulic path to the tank unit through a return port formed in the block unit.

[0049]

[0041] In another preferred embodiment, braking pressure is regulated by varying a rotational speed of the motor.

[0050]

[0042] In another preferred embodiment, pressurisation and depressurisation of the braking circuit occur through the same internal hydraulic path within the block unit.

[0051]

[0043] In another preferred embodiment, reducing or stopping the motor causes hydraulic pressure to dissipate through the return port without operation of a hydraulic valve or solenoid.

[0052]

[0044] Other aspects of the invention are also disclosed.Brief Description of the Drawings

[0053]

[0045] Notwithstanding any other forms which may fall within the scope of the present invention, preferred embodiments of the present invention will now be described, by way of examples only, with reference to the accompanying drawings in which:

[0054]

[0046] Figure 1 is a perspective view of an actuator assembly in accordance with a first preferred embodiment of the present invention;

[0055]

[0047] Figure 2 is a perspective view of the actuator assembly, with the tank unit, block unit and the motor cover shown transparent for illustration purposes;

[0056]

[0048] Figure 3(a) is a side view of a sub-assembly showing the motor, block unit and pump with the block unit shown transparent, 3(b) is a perspective view of 3(a) with the block unit shown solid, and 3(c) is a perspective view of 3(a) with the block unit shown transparent.

[0057]

[0049] Figure 4(a) is a front view of the block unit shown transparent, 4(b) is a side view of the block unit shown transparent, and 4(c) is a front view the block unit shown solid; and

[0050] Figure 5 is a front view of the pump mounted to the block unit shown transparent

[0051] Figure 6 is a front view of a modified version of the block unit (shown transparent), with the second outlet port located at a different position to that shown in Figure 4, and

[0058]

[0052] Figure 7(a) shows a perspective view of an example removable cartridge for the return port and (b) shows a cross-section view of the example cartridge.

[0059] Description of Embodiments

[0060]

[0053] It should be noted in the following description that like or the same reference numerals in different embodiments denote the same or similar features.

[0061]

[0054] Figures 1 and 2 show an actuator assembly 10 which externally comprises a tank unit 20, a valveless block unit 30 and a motor cover 40. The block unit 30 is between the motor cover 40 and the tank unit 20.

[0062]

[0055] The actuator assembly 10 further comprises a pump 22 disposed at one side of the block unit 30 and within tank unit 20, and a motor 42 at the opposite side of the block unit 30 and covered by the motor cover 40. The block unit 30 has an internal path 31 formed therein, connected to an inlet port 33, a first outlet port 32 and a second outlet port 34.

[0063]

[0056] The tank unit 20 in use is filled with hydraulic fluid, and the motor 42 is coupled to the pump 22 for rotating an impeller or driving a piston of the pump 22 at high speed as required. The pump 22 receives fluid from within the tank 20, delivers hydraulic fluid under pressure through the inlet port 33 into the internal path 31 and ejects the fluid at high pressure from the second outlet port 34 of the block unit 30 in a first embodiment. The second outlet port 34 ishydraulically connected to one or more brake callipers for actuating the callipers. Simultaneously, a continuous but minor flow of hydraulic fluid returns to the tank unit 20 via the fixed-orifice first outlet port 32 which functions as return jet port. The second outlet port 34 thus acts as an actuation port (brake delivery port) and the first outlet port 32 acts as a return jet port being a fixed orifice return path for controlled pressure dissipation.

[0064]

[0057] In a second (alternative) embodiment, the functions of the second outlet port 34 and the first outlet port 32 are reversed, in that pressurised fluid is instead ejected from the first outlet port 32 to one or more brake callipers. Simultaneously, a continuous but minor flow of hydraulic fluid returns to the tank unit 20 via the fixed-orifice second outlet port 34 which functions as a return jet port. In this second embodiment, the first outlet port 32 acts as the actuation port and the second outlet port 34 acts as the return jet port.

[0065]

[0058] In both the first and second embodiments, the return port is substantially smaller than the actuation port, and thus the return port presents significantly higher flow resistance such that the majority of pressurised fluid is directed to the brake callipers during pressurisation via the actuation port.

[0066]

[0059] Additional details regarding the above components will now be described. It will be seen from the description of the block unit 30 and the internal path 31 below, that the actuation port and return port functions, being between the first outlet port 32 and second outlet port 34 can be interchangeable as desired depending on relative port diameter configurations therebetween. The first embodiment will be firstly described where the second outlet port 34 acts as the actuation port and the first outlet port 32 acts as the return port.

[0067]

[0060] Referring to Figures 2 to 4, the block unit 30 is generally a rectangular block having a pump side face 36 and a motor side face 37. The block unit 30 starts as a solid block piece which is drilled from a lower side face and a lateral side face thereof to form internal vertical channel 35a and horizontal channel 35b which intersect at point 35c. The channels 35a and 35b are blind drilled bores. The drilled openings at the lower side face and the lateral side face are closed / plugged at 38, and the remaining channels 35 within the block unit 30 form the internal path 31. An axle aperture 39 is drilled / formed between the pump side face 36 and the motor side face 37 for an axle 44 coupling the motor 42 to the pump 22.

[0068]

[0061] The pump side face 36 includes the first outlet port 32, the inlet port 33 and the second outlet port 34, with all three ports 32 to 34 being connected to the internal path 31. In other words, the ports 32 to 34 are drilled bores from the pump side face 36 to the internal path 31. In the example shown, the inlet port 33 and the second outlet 34 are disposed along the vertical channel 35a. The inlet port 33 is adjacent the central axle aperture 39, and the second outlet 34 is close and above the inlet port 33, at the distal end of the vertical channel 35a. Thefirst outlet port 32 is disposed close to the lower side face and at a distance from the inlet port 33. The first outlet port 32 is disposed at the distal end of the horizontal channel 35b. The internal path 31 from the inlet port 33 to the first outlet port 32 also includes a 90° turn being at the intersection 35c of the channels 35.

[0069]

[0062] The tank unit 20 is a hollow rectangular prism body which has an end wall 26 and four side walls 23 extending therefrom. The tank unit 20 has an open side opposite the end wall 26, the open side being closed by the block unit 30. The pump 22 and the motor 42 can be mounted to the opposing sides of the block unit 30, with suitable seals such as gaskets, O-rings, 41 etc being arranged therebetween to provide a fluid tight tank chamber 21 within the tank unit 20. The tank unit 20 includes a refilling opening 25 which can be closed with a cap.. The tank chamber 21 is filled with hydraulic fluid in use.

[0070]

[0063] The motor 42 is coupled via an axle 44 extending through the block unit 30 to the pump 22, for rotating an impeller or driving a piston of the pump 22. Suitable seals and gaskets are provided to the axle 44 and the motor 42 to ensure the tank chamber 21 remains fluid tight.

[0071]

[0064] An inlet 24 of the pump 22, being within the hydraulic bath within the tank chamber 21 in use, receives hydraulic fluid into the pump 22. An outlet of the pump 22 is connected to the inlet port 33 of the block unit 30. During use, when braking, the motor 42 receives a signal to actuate the pump 22 (rotate the pump impeller / drive the pump piston) at high speed, typically around 3000 to 4000 rpm. This leads to high pressure fluid of 1600psi to 2500psi being ejected from the second outlet port 34. Simultaneously, a continuous but minor flow of hydraulic fluid returns to the tank unit 20 via the fixed-orifice first outlet port 32. This continuous return flow is intentional and functional. For a given motor speed, the diameter of the return port orifice (the first outlet port 32 in this embodiment) determines the maximum attainable braking pressure by governing the proportion of fluid that continuously returns to the tank chamber 21 during pressurisation. Braking pressure is proportional to motor speed, providing fine proportional control across the full operating range, including at high-pressure conditions where precise modulation is most critical

[0072]

[0065] Pressure range is substantially linear from 0 to max rpm (the pump is able to deliver proportional fluid flow at very low pressures.) When braking function is slowed or ceases, the motor 42 slows or stops rotation of the pump 22 impeller or movement of the pump piston, which allows braking fluid to flow back to the tank chamber 21 via the first outlet port 32. Pressure dissipation from 1600psi is currently 80 milliseconds, which is a good outcome, and can be possibly reduced further as the system is refined. Using a brushless motor in the preferred embodiment, the applicant is able to stop the motor and dissipate energy immediately.

[0066] The second outlet port 34 can be directly fluidly connected to the brake calliper line(s). Alternatively, the tank unit 20 can include an internal line connecting to the second outlet port 34, where the brake calliper line can be connected to the internal line. This allows lines to be externally connected to the actuator assembly 10.

[0073]

[0067] As noted above, in a second (alternative) embodiment, the functions of the second outlet port 34 and first outlet port 32 are reversed, in that pressurised fluid is instead ejected from the first outlet port 32 to one or more brake callipers. Simultaneously, a continuous but minor flow of hydraulic fluid returns to the tank unit 20 via the fixed-orifice second outlet port 34. This is the preferred embodiment. In this second (preferred) embodiment, the first outlet port 32 acts as the actuation port and the second outlet port 34 acts as the return jet port. The relative diameters of the apertures of the second outlet port 34 and first outlet port 32 are suitably chosen for their respective roles.

[0074]

[0068] The first outlet port 32 in this second embodiment is directly fluidly connected to a fluid passageway 29 formed tank unit 20. The fluid passageway 29 includes an outlet 27 at the end wall 26, the outlet 27 allowing for attachment to the brake calliper line(s). Alternatively, the tank unit 20 can include the internal line connecting to the first outlet port 32, where the brake calliper line can be connected to the internal line. This allows lines to be externally connected to the actuator assembly 10. Braking pressure is delivered through the first outlet port (32) and regulated entirely through motor speed control, without the use of a hydraulic valve or solenoid. When the motor (42) is actuated, it drives the pump (22) to draw hydraulic fluid from the tank unit (20) and deliver hydraulic fluid at high pressure, ranging from 20 to 2000 psi, through the first outlet port (32) to one or more brake callipers. Pressure is proportional to motor speed, enabling fine proportional control across the full operating range including at high-pressure conditions where precise modulation is most critical. When braking is reduced or ceased, the motor (42) slows or stops and fluid returns to the tank unit (20) via the second outlet port (34).

[0075]

[0069] In further preferred embodiments, a pressure sensor (45) is provided in fluid communication with the internal hydraulic path (31 ) of the block unit (30). The pressure sensor (45) enables closed-loop control of braking pressure and facilitates detection of wear, blockage, or degradation of the flow restriction, including changes in hydraulic behaviour indicative of orifice erosion or partial obstruction.

[0076]

[0070] In the illustrated embodiment, the pressure sensor (45) is mounted to the motor side face (37) of the block unit (30) and enclosed by the motor cover 40. The pressure sensor (45) extends into the block unit (30) through a fourth port (46) formed in the motor side face (37) and fluidly connected to the internal hydraulic path (31).

[0071] As also shown in Figure 6, the fourth port (46) extends from the motor side face (37) to the internal hydraulic path (31) and, in the example shown, is disposed in communication with the horizontal channel (35b) of the internal path. The fourth port (46) is positioned adjacent the closure plug (38) sealing the horizontal channel (35b).

[0077]

[0072] In particular, the fourth port (46) is located on the opposite side of the intersection point (35c) from the first outlet port (32), thereby enabling pressure measurement at a region of the internal hydraulic path (31) that is hydraulically downstream of the pump inlet and spatially separated from the actuation port. This positioning allows accurate sensing of system pressure while minimising flow disturbance and enhancing diagnostic reliability.

[0078]

[0073] The hydraulic circuit of the block unit (30) is a single-path bidirectional architecture. Both pressurisation and depressurisation occur through the same internal path, fluid is delivered to the brake callipers via the first outlet port (32) during pressurisation, and returns through the same path upon depressurisation. Unlike conventional two-way hydraulic circuits employing separate pressurisation and return lines managed by a valve, the present embodiments manage all fluid return through the fixed-orifice return jet port (second outlet port 34 in the second embodiment) branching from within the block unit (30) itself. There is no external return line. The complete hydraulic circuit is consolidated within the single machined block unit (30), reducing external connections, potential leak points, and system complexity.

[0079]

[0074] The return port (second outlet port 34 in the second embodiment) is a fixed-geometry orifice whose diameter is selected to achieve a target maximum brake pressure and affect pressure dissipation rate upon cessation of a braking demand signal. The block unit (30) is entirely free of any hydraulic valve or solenoid.

[0080]

[0075] Hydraulic fluid delivered by the pump (22) into the internal hydraulic path (31) of the block unit (30) exits the block unit (30) simultaneously through both an actuation port and a return port during pressurisation. In the preferred embodiment, the first outlet port (32) functions as the actuation port for delivering pressurised hydraulic fluid to one or more brake callipers, while the second outlet port (34) functions as the return port, the second outlet port (34) being configured as a jet port having a relatively small orifice. The first outlet port (32) is formed with a larger effective flow area than the second outlet port (34). As a result of the differing hydraulic resistances, the hydraulic fluid flow divides between the two ports such that the majority of the pump output is delivered through the first outlet port (32) to the brake callipers, while a smaller portion of the hydraulic fluid is continuously returned to the tank unit (20) through the second outlet port (34).

[0081]

[0076] In this embodiment, the actuation port being the first outlet port (32) delivers hydraulic fluid at relatively high static pressure and lower exit velocity to the brake callipers, enablingthe generation of braking force. At the same time, the return port being the second outlet port (34) produces a high-velocity, lower-pressure jet of hydraulic fluid returning to the tank chamber (21) of the tank unit (20). Although the velocity and pressure characteristics at the first outlet port (32) and the second outlet port (34) differ, the total volumetric flow delivered by the pump (22) is conserved, with the flow distribution being governed by the relative orifice diameters of the first outlet port (32) and the second outlet port (34). The continuous return flow through the second outlet port (34) stabilises braking pressure and enables rapid and predictable pressure dissipation when the motor (42) speed is reduced or ceased. This configuration is particularly suited to higher-pressure braking systems, including braking systems for trailers and motor vehicles.

[0082]

[0077] In a preferred embodiment, the block unit (30) is machined from aluminium, providing a favourable combination of strength, machinability, and resistance to hydraulic fluid corrosion.

[0083]

[0078] In a preferred embodiment, the motor (42) is a brushless DC motor operating at 12 or 24 volts. The brushless motor can be stopped rapidly and dissipate energy immediately upon cessation of a braking demand signal, enabling rapid pressure release without a valve mechanism.

[0084]

[0079] The pump (22) is disposed within the tank unit (20) on the pump side face (36) of the block unit (30), with the pump inlet (24) continuously submerged in hydraulic fluid. This ensures consistent fluid supply and reduces wear. The pump (22) may be an impeller-type or piston-type pump, or any other type suitable for generating hydraulic pressure in the range of 20 to 2,000 psi.

[0085]

[0080] Operation

[0086]

[0081] During a braking event, the motor (42) receives a braking demand signal and actuates the pump (22). This continuous return flow is intentional and functional. For a given motor speed, the diameter of the second outlet port orifice (34) determines the maximum attainable braking pressure by governing the proportion of fluid that continuously returns to the tank unit (20) during pressurisation. Braking pressure is proportional to motor speed, providing fine proportional control across the full operating range, including at high-pressure conditions where precise modulation is most critical.

[0087]

[0082] In a preferred embodiment, a second outlet port 34 orifice diameter of 0.2 mm to 0.3mm in combination with a substantially larger first outlet port 32 delivers braking pressures across the full operating range of 20 to 2,000 psi.

[0088]

[0083] When braking demand is reduced or ceased, the motor (42) slows or stops. Hydraulic pressure in the braking circuit dissipates and fluid returns through the first outlet port (32) backalong the internal path (31), exiting via the fixed-orifice second outlet port (34) into the tank unit (20) at high velocity. All depressurisation occurs through the same internal path as pressurisation, the single-path bidirectional architecture, with no external return line. The diameter of the second outlet port (34) governs the rate of fluid return and thus the rate of pressure dissipation, ensuring controlled and predictable pressure release.

[0089]

[0084] In a preferred embodiment, the second outlet port orifice diameter and motor configuration together achieve depressurisation to ambient pressure in approximately 150 milliseconds, though this figure varies depending on system configuration, second outlet port diameter, and operating pressure at the time of cessation.

[0090]

[0085] Electronic Control Unit

[0091]

[0086] In the preferred embodiment, the assembly (10) further comprises an Electronic Control Unit (ECU) configured to receive a proportional braking demand signal from one or more input sources, including but not limited to a host vehicle braking system, an IMU, an accelerometer, a standalone brake controller, an autonomous driving system, or any other sensor or control system capable of generating a braking demand signal. The ECU dynamically adjusts motor speed to regulate hydraulic pressure at the first outlet port (32), delivering smooth and proportional braking across the full operating range. The ECU may additionally incorporate fail-safe mechanisms, diagnostic capabilities, and fault detection and reporting.

[0092]

[0087] Modified and Alternative Embodiments

[0093]

[0088] Figure 6 shows a modified version of the block unit (30) with the second outlet port (34) located at a different position to that shown in Figure 4. In this embodiment, the inlet port (33) and the second outlet port (34) are still disposed along the vertical channel (35a). The difference is the inlet port (33) is positioned adjacent a closed end of the vertical channel (35a), while the second outlet port (34) is disposed below the inlet port (33) along the vertical channel (35a) and spaced from the closed end. The second outlet port (34) is disposed close to the intersection point 35c. In this arrangement, hydraulic fluid introduced into the internal hydraulic path (31) through the inlet port (33) flows downward along the vertical channel (35a) as part of a single flow stream.

[0094]

[0089] The first outlet port (32) is disposed at the distal end of the horizontal channel (35b) and is positioned closer to a lower side face of the block unit (30). Hydraulic fluid flowing along the vertical channel (35a) continues past the second outlet port (34) and turns at the intersection point (35c) to enter the horizontal channel (35b) before exiting the block unit (30) via the first outlet port (32).

[0090] Accordingly, in this embodiment, the inlet port (33), the second outlet port (34), and the first outlet port (32) are arranged along a common hydraulic flow path within the internal hydraulic path (31 ). Both outlet ports 32 and 34 communicate with the same flow stream rather than being supplied by separate, diverging flow paths from the inlet port (33). This configuration avoids flow separation within the block unit (30) and provides a sequential flow arrangement in which hydraulic fluid encounters the second outlet port (34) and the first outlet port (32) along the same internal flow stream.

[0095]

[0091] In alternative embodiments, the motor and pump may be disposed on the same side of the block unit rather than on opposing sides. In such embodiments, the motor and pump may be arranged in a stacked or axial configuration wherein the motor is mounted directly adjacent to, or coaxially aligned with, the pump on a common side of the block unit.

[0096]

[0092] In one embodiment, the pump may be mounted directly to the pump-side face of the block unit, with the motor mounted to the pump such that the motor shaft couples directly to an impeller or piston of the pump. In this configuration, the motor does not extend through the block unit, and the block unit does not require an axle aperture extending fully between opposing faces. The internal hydraulic path of the block unit remains unchanged, with the pump outlet being fluidly connected to the inlet port of the block unit and hydraulic fluid being delivered to and returned from the braking circuit through the internal path.

[0097]

[0093] In another embodiment, the motor and pump may be integrated into a combined motor-pump module mounted to a single face of the block unit. The combined module may be received within the tank unit such that the pump inlet remains submerged in hydraulic fluid during operation, while the motor is sealed from the fluid chamber by suitable seals, gaskets, or barriers.

[0098]

[0094] Placing the motor and pump on the same side of the block unit may reduce overall assembly width, simplify sealing arrangements, and facilitate manufacturing or packaging where space constraints exist. This configuration may also reduce the number of penetrations through the block unit and simplify alignment of rotating components.

[0099]

[0095] In further embodiments, the tank unit may include an internal hydraulic line connected to the actuation port (first outlet port 32 in the second embodiment), allowing external brake calliper lines to be connected while maintaining an internal return path through the second outlet port.

[0100]

[0096] In further embodiments, the motor may operate at voltages higher than 24 volts, including but not limited to 48 volts or 96 volts, particularly for electric vehicle or high-performance braking applications. Higher voltage operation enables greater motor power output and faster pressure response, making the assembly particularly suitable for high-performance electric vehicle braking applications where rapid and precise pressure modulation is critical.

[0101]

[0097] In a further alternative embodiment, the motor (42) may be a brushed DC motor in place of the preferred brushless DC motor. While the brushless motor is preferred for its rapid energy dissipation and long service life, a brushed DC motor may be employed in costsensitive applications or where existing vehicle electrical systems are optimised for brushed motor operation. Pressure regulation through motor speed control is equally applicable in brushed motor configurations.

[0102]

[0098] In a further alternative embodiment, the actuator assembly (10) may be configured for use in non-automotive braking and actuation applications, including but not limited to unmanned aerial vehicles (UAVs), planetary rovers, and other unmanned platforms requiring precise hydraulic pressure actuation. In such applications, the braking demand signal may be received from an autonomous flight or navigation control system, and the assembly may be adapted for operation across a range of environmental conditions including low atmospheric pressure, extreme temperatures, and high vibration environments. The compact and valveless architecture of the assembly is particularly advantageous in weight-critical and space-constrained platforms.

[0103]

[0099] In a further alternative embodiment, the actuator assembly (10) may be configured to supply pressurised hydraulic fluid to brake callipers across multiple axles of a trailer or vehicle. In such configurations, the first outlet port (32) may be connected to a hydraulic distribution manifold supplying two or more independent brake calliper circuits, with braking pressure across all circuits regulated simultaneously through motor speed control. This configuration is particularly suited to multi-axle trailers and heavy vehicles where a single actuator assembly is preferred for simplicity, weight reduction, and cost efficiency.

[0104]

[0100] In a further alternative embodiment, the actuation port (first outlet port 32 in the second embodiment) may be dimensioned to be substantially smaller than the return port (second outlet port 34 in the second embodiment), in contrast to the preferred embodiment in which the return port orifice is substantially smaller than the actuation port. In this configuration, the reduced actuation port diameter produces a higher velocity flow of pressurised hydraulic fluid delivered to the brake callipers, while the larger return port diameter facilitates rapid return of fluid to the tank unit (20) upon depressurisation. This configuration is particularly suited to applications where high delivery velocity at the braking element and fast depressurisation are prioritised. Maximum attainable braking pressure and pressure dissipation rate are governed by the same principles as the preferred embodiment, with the relative diameters of the firstoutlet port (32) and second outlet port (34) selected according to the target operating characteristics of the application.

[0105]

[0101] In this alternative embodiment, the actuation port being the first outlet port (32) is formed with a smaller effective flow area than the second outlet port (34), such that pressurised hydraulic fluid is delivered to the brake callipers at higher exit velocity and lower static pressure. Simultaneously, the larger-diameter second outlet port (34) provides a lower- resistance return path, allowing hydraulic fluid to return to the tank chamber (21 ) at lower velocity and higher relative pressure upon reduction or cessation of braking demand.

[0106]

[0102] In this alternative configuration, hydraulic fluid similarly exits the block unit (30) simultaneously through both the first outlet port (32) and the second outlet port (34) during pressurisation, with the distribution of flow being determined by the relative hydraulic resistances of the ports. This embodiment may be advantageous in applications requiring lower braking force and rapid fluid response, such as lightweight or low-speed vehicles equipped with small brake callipers, including small autonomous transport or delivery platforms. By appropriate selection of the relative diameters of the first outlet port (32) and the second outlet port (34), the hydraulic behaviour of the actuator assembly (10) may be tailored to suit different braking force, response time, and vehicle operating requirements.

[0107]

[0103] Definitions

[0108]

[0104] The following definitions apply to the embodiments described in this specification unless the context expressly requires otherwise. These definitions are provided for clarity and are not intended to limit the scope of protection.

[0109]

[0105] "Electric Hydraulic Brake" or "EHB" in the embodiments described refers to a system in which an electrical input signal is used to drive a motor-powered hydraulic pump, which in turn generates hydraulic pressure for actuating one or more elements. The term encompasses any system architecture in which electrical control is the primary means of initiating and modulating hydraulic braking pressure.

[0110]

[0106] "Braking element" in the embodiments described refers to any hydraulically actuated device capable of applying a retarding or stopping force, including but not limited to brake callipers, brake cylinders, drum brake actuators, and any functionally equivalent component across road, aerospace, marine, rail, or industrial machinery applications.

[0111]

[0107] "Return port" in the embodiments described refers to the port of the block unit through which hydraulic fluid continuously returns to the tank unit during operation. During pressurisation, the return port orifice, being substantially smaller than the actuation port, presents significantly higher flow resistance such that the majority of fluid is directed to thebrake callipers via the actuation port, with a continuous but minor flow returning to the tank unit via the return port. This continuous return flow is intentional and functional, as the return port orifice diameter determines the maximum attainable brake pressure, for a given motor speed, by governing the proportion of fluid that returns to the tank unit during pressurisation. Upon depressurisation, fluid returns to the tank unit at high velocity via the return port. The return port orifice diameter also governs the rate of pressure dissipation upon cessation of a braking demand signal. The return port orifice has no bearing on upward pressure modulation, which is regulated purely by motor speed. In preferred embodiments, the return port opens directly into the fluid chamber of the tank unit, with the return port orifice continuously submerged in hydraulic fluid during operation.

[0112]

[0108] "Actuation port" in the embodiments described refers to the port through which pressurised hydraulic fluid is delivered from the internal path of the block unit to one or more brake callipers. The actuation port is the high-pressure delivery port of the assembly.

[0113]

[0109] "Inlet port" in the embodiments described refers to the port through which hydraulic fluid enters the internal path of the block unit from the pump.

[0114]

[0110] "Internal path" in the embodiments described refers to the network of internal channels formed within the block unit connecting the inlet port, second outlet port, and outlet port. The internal path constitutes the complete hydraulic circuit of the block unit.

[0115]

[0111] "Single-path bidirectional architecture" in the embodiments described refers to a hydraulic circuit configuration in which pressurisation and depressurisation of the braking circuit share a single common internal path, as distinguished from conventional two-way hydraulic circuits in which separate dedicated lines are provided for pressurisation and fluid return. In the single-path bidirectional architecture, fluid flows toward the braking elements during pressurisation and returns along the same path during depressurisation, with return flow managed by the fixed-orifice second outlet port branching from within the block unit.

[0116]

[0112] "Block unit" in the embodiments described refers to the solid machined block forming part of the actuator assembly, having the internal path, inlet port, outlet port, and second outlet port formed therein. The block unit consolidates the complete hydraulic circuit within a single component and, in preferred embodiments, forms a sealed wall of the tank unit.

[0117]

[0113] "Tank unit" in the embodiments described refers to the fluid reservoir forming part of the actuator assembly for storing hydraulic fluid. In preferred embodiments, the tank unit houses the pump and forms a sealed fluid chamber with the block unit as one wall.

[0118]

[0114] "Motor speed control" or "varying motor speed" in the embodiments described refers to the modulation of the rotational speed of the motor as the primary and sole active means ofregulating hydraulic braking pressure in the assembly. No hydraulic valve, solenoid, or other active pressure-regulating component is employed.

[0119]

[0115] "Proportional braking pressure" in the embodiments described refers to hydraulic braking pressure that varies in a controlled and graduated manner in response to a braking demand signal, including but not limited to substantially linear relationships between motor speed and output pressure. The term encompasses any graduated pressure response achievable through motor speed modulation, and is not limited to strictly linear pressure-speed relationships.

[0120]

[0116] "Braking demand signal" in the embodiments described refers to any electrical, electronic, or data signal indicative of a request to apply, modulate, or release braking pressure, received from any input source including but not limited to a host vehicle braking system, an inertial measurement unit (IMU), an accelerometer, a standalone brake controller, an autonomous driving system, a pilot input system, an operator control interface, or any sensor or control system capable of generating such a signal across any application domain.

[0121]

[0117] "ECU" or "Electronic Control Unit" in the embodiments described refers to any electronic controller, microcontroller, processor, or control module configured to receive a braking demand signal and output a motor speed command. The term is not limited to automotive ECUs and encompasses any equivalent electronic control device across all application domains covered by this invention.

[0122]

[0118] "Automotive applications" in the embodiments described is used in this specification as a broad descriptive term encompassing road vehicles and is not intended to limit the scope of the invention, which extends to all vehicles, machines, and platforms described herein.

[0123]

[0119] "Vehicle" in the embodiments described refers to any conveyance, machine, or platform requiring hydraulic braking or pressure actuation, including but not limited to road vehicles, aircraft, watercraft, rail vehicles, and heavy machinery, whether manned or unmanned, autonomous or operator-controlled.

[0124]

[0120] The present embodiments provide a number of advantages.

[0125]

[0121] The braking system components are enclosed within a robust housing that provides protection from environmental factors such as dust, moisture, and mechanical impact. The housing is designed to be compact yet durable, ensuring long-term operational reliability.

[0126]

[0122] Electric Motor: A 12 or 24-volt DC electric motor 42 powers the hydraulic pump 22. The motor 42 receives control signals from the electronic control unit (ECU) and adjusts its speed accordingly to regulate hydraulic pressure. The motor is designed for high efficiency, ensuring rapid response times while minimizing power consumption.

[0123] Hydraulic Pump: The hydraulic pump 22 is directly coupled to the electric motor 42, which drives its operation. The pump 22 is responsible for generating hydraulic pressure within the braking system. The pump 22 is disposed within a brake fluid chamber that ensures continuous immersion in brake fluid, reducing wear and maintaining performance. The pump features an inlet with a filter to prevent contamination and a pump outlet that directs pressurized fluid into the hydraulic block unit.

[0127]

[0124] Hydraulic Block: A solid hydraulic block unit 30 forms one side of the brake fluid tank chamber 21 and serves as the main conduit for hydraulic fluid distribution. The block unit 30 has an internal fluid path that directs hydraulic fluid between various system components. It includes three apertures: an inlet port , which is connected to the pump outlet to receive pressurized brake fluid. A brake fluid outlet port, which allows unpressurised fluid to return to the tank chamber 21. A second outlet output port, which connects to an outlet path leading to the hydraulic brake circuit, ensuring regulated pressurised flow towards the brake callipers. In another embodiment, the roles of the fluid outlet port and the second outlet output port are reversed.

[0128]

[0125] Reduced Flow Channel: A precision-engineered small orifice (the return port (32 or 34)) is integrated within the system to regulate the return flow of hydraulic fluid to the reservoir tank chamber 21. This return channel ensures that adequate pressure is maintained in the braking circuit while allowing for immediate pressure release when braking force is no longer required. The design of the reduced flow return channel enhances braking efficiency and prevents fluid pressure surges.

[0129]

[0126] Electronic Control Unit (ECU): The ECU receives proportional control signals from the towing vehicle's braking system, typically via a brake controller. Based on the received signals, the ECU dynamically adjusts the motor speed to regulate hydraulic pressure, ensuring smooth and proportional braking performance. The ECU may incorporate additional safety features, such as fail-safe mechanisms and diagnostic capabilities, to enhance system reliability.

[0130]

[0127] Operational Overview: When the towing vehicle's driver applies the brakes, a proportional electronic signal is sent to the ECU. The ECU processes the signal and adjusts the motor speed accordingly. The motor drives the hydraulic pump, generating pressurized brake fluid, which is directed through the hydraulic block to the brake callipers of the trailer. The reduced flow channel ensures controlled pressure release, allowing for smooth braking action and immediate response when braking is disengaged.

[0131]

[0128] Advantages of the Improved System:• Faster response time as braking pressure is generated and regulated entirely through motor speed control, without the use of any hydraulic valve, solenoid, or switching element .

[0132] • Greater Brake Pressure Range: Improved control, especially in the lower pressure range.

[0133] • Linear Proportional Response: More consistent and predictable fluid flow and brake pressure.

[0134] • Reduced Current Draw: Less energy consumption due to the simplified design.

[0135] • Enhanced Reliability: Fewer mechanical parts result in a more robust and dependable system.

[0136] • Cost-Effective: Lower production costs due to fewer components and simplified assembly.

[0137] • Compact and Lightweight: The removal of the hydraulic valve allows for a smaller and lighter system.

[0138] • A tank unit for holding hydraulic fluid in a sealed fluid chamber

[0139] • A block unit having a single internal hydraulic path connecting an inlet port, an outlet port, and a second outlet port

[0140] • A pump disposed within the tank unit and submerged in hydraulic fluid during operation • A motor driving the pump to generate hydraulic pressure

[0141] • Delivery of pressurised hydraulic fluid directly to one or more brake callipers through an outlet port

[0142] • Regulation of braking pressure solely by varying motor speed, without hydraulic valves or solenoids

[0143] • A single-path bidirectional hydraulic architecture consolidating pressurisation and depressurisation within the block unit

[0144] • A fixed-orifice second outlet port providing controlled continuous return flow and pressure dissipation

[0145] • Continuous minor return flow during pressurisation to stabilise pressure

[0146] • Rapid pressure decay upon reduction or cessation of braking demand• Generation of braking pressures across a wide operating range, including low-pressure and high-pressure regimes

[0147] • Improved low-pressure proportional braking response

[0148] • Reduced electrical current draw compared to valve-based systems

[0149] • Faster system response due to elimination of mechanical valve actuation delays • Reduced component count and simplified assembly

[0150] • Increased reliability due to elimination of valve failure modes

[0151] • Compact, lightweight, and robust construction

[0152] • Integration with electronic control systems including autonomous platforms

[0153] • Applicability across automotive, industrial, aerospace, marine, rail, and robotic systems

[0154] • Suitability for multi-axle braking architectures

[0155]

[0129] The present invention in one use is for a braking system for trailers. The invention will also have application in primary braking systems for motor vehicles (heavy 12-tonne and passenger vehicles). It also has specific uses with electric vehicles, autonomous vehicles, and commercial vehicles.

[0156]

[0130] The preferred embodiments thus provide an Electric Hydraulic Brake (EHB) actuator assembly for a hydraulic braking system suitable for use across automotive applications including trailers, passenger vehicles, commercial vehicles, heavy vehicles, electric vehicles, and autonomous vehicles. The assembly comprises a tank unit for holding hydraulic fluid, a block unit having an internal path with an inlet port, an outlet port, and a second outlet port, a pump disposed within the tank unit, and a motor for driving the pump. When actuated, the pump delivers hydraulic fluid at high pressure through the outlet port to one or more brake callipers, with braking pressure regulated entirely by varying motor speed, without a hydraulic valve or solenoid. The second outlet port allows hydraulic fluid to return to the tank unit at high velocity upon depressurisation. The hydraulic circuit is a single-path bidirectional architecture in which pressurisation and depressurisation share a single internal path, with fluid return managed by a fixed-orifice second outlet port entirely within the block unit. An optional Electronic Control Unit dynamically adjusts motor speed to achieve proportional braking pressure across the full operating range.

[0131] The Electric Hydraulic Brake (EHB) actuator assembly is suitable for use across any vehicle, machine, or platform employing hydraulic braking or hydraulic pressure actuation, including but not limited to road vehicles such as trailers, passenger vehicles, commercial vehicles, heavy vehicles, electric vehicles, and autonomous vehicles; heavy machinery including excavators, cranes, and mining equipment; aircraft and aerospace platforms; marine and watercraft applications; and rail vehicles. The disclosure provides an integrated actuator assembly in which a motor-driven pump delivers hydraulic fluid at high pressure through an outlet port formed within a single hydraulic block unit, enabling fine proportional braking pressure control across the full operating range, including at high-pressure operating conditions in both low and high pressure ranges, from 20 to 2,000 of pounds per square inch, without the use of a hydraulic valve or solenoid. The hydraulic circuit of the block unit is a single-path bidirectional architecture in which pressurisation and depressurisation share a single internal path, with all fluid return managed by a fixed-orifice second outlet port entirely within the block unit, eliminating the need for a separate return line.

[0157]

[0132] In preferred embodiments, the actuator assembly is configured as a fully valveless Electric Hydraulic Brake (EHB) actuator in which hydraulic braking pressure is generated, regulated, and released entirely by electronic control of motor speed. No hydraulic valve, proportional solenoid, or mechanical switching element is employed at any point during pressurisation or depressurisation of the braking circuit.

[0158]

[0133] The actuator assembly employs a single-path bidirectional hydraulic architecture in which pressurisation and depressurisation of the braking circuit share a single common internal hydraulic path formed entirely within the block unit. Unlike conventional EHB or EOH systems that rely on a valve-controlled return path, all hydraulic flow management in the present invention occurs through fixed geometry features of the block unit, in combination with dynamic motor speed control.

[0159]

[0134] This architecture eliminates the inherent response delay, current draw, thermal load, and mechanical wear associated with valve-based pressure regulation, while enabling fast, predictable, and repeatable pressure modulation across both low-pressure and high-pressure operating regimes.

[0160]

[0135] In preferred embodiments, the actuator assembly further comprises an Electronic Control Unit (ECU) configured to receive one or more braking demand signals and output corresponding motor speed commands.

[0161]

[0136] Braking demand signals may be received from a wide variety of sources including, but not limited to, a host vehicle braking system, a trailer brake controller, an inertial measurementunit (IMU), an accelerometer, an autonomous driving control system, or another electronic control interface.

[0162]

[0137] The ECU processes the braking demand signal and dynamically adjusts motor speed in real time to regulate hydraulic pressure at the outlet port, providing smooth and proportional braking response. In further embodiments, the ECU may incorporate one or more fail-safe mechanisms, diagnostic functions, fault detection, and fault reporting capabilities.

[0163]

[0138] The preferred embodiments relate primarily to electro-hydraulic braking systems for trailers and motor vehicles, and to a solid-state hydraulic pressure modulation system utilising a variable-speed pump in combination with a fixed-geometry flow restriction.

[0164]

[0139] Traditional electro-hydraulic (EOH) braking systems rely on hydraulic valves and solenoids to regulate braking pressure. These systems introduce mechanical complexity, slower response times, higher current draw, and increased failure modes.

[0165]

[0140] The preferred embodiments aim to overcome or substantially ameliorate at least some of the deficiencies of the prior art by eliminating valve-based pressure regulation and replacing it with a solid-state hydraulic control architecture.

[0166]

[0141] In one aspect, the preferred embodiments provide an electro-hydraulic actuator assembly comprising a pump, motor, hydraulic manifold, and a fixed-geometry flow restriction.

[0167]

[0142] In a preferred embodiment, the flow restriction is configured as a pressure-regulating bypass returning fluid to a reservoir. Hydraulic pressure is actively controlled by varying motor speed relative to the restriction.

[0168]

[0143] This establishes a pre-charged hydraulic circuit in which fluid is continuously in motion, enabling near-instantaneous pressure response and reduced system latency.

[0169]

[0144] In alternative embodiments, the flow restriction may be positioned within the delivery path to provide flow dampening characteristics. In the alternative iteration (jet to calliper), the flow or pressure will be smoother without aggressive pressure changes with gradual finer pressure changes, which may be suitable for different applications, smaller robotic autonomous vehicles . In this version, higher velocity and much lower pressure fluid is delivered to the callipers instead of the other preferred version of low velocity and high pressure.

[0170]

[0145] The system in one aspect comprises a hydraulic reservoir, a pump disposed within the reservoir, an electric motor configured to drive the pump, and a monolithic hydraulic manifold containing internal flow paths.

[0146] Hydraulic fluid is simultaneously delivered to braking elements and diverted through a flow restriction to the reservoir.

[0171]

[0147] Pressure-Regulating Bypass

[0172]

[0148] In the preferred embodiment, the flow restriction forms a bypass path returning fluid to the reservoir.

[0173]

[0149] During operation, the pump continuously circulates hydraulic fluid through the internal flow path and the bypass restriction, maintaining a baseline hydraulic energy state.

[0174]

[0150] Upon increase in motor speed, pressure rises as pump output exceeds the flow capacity of the restriction.

[0175]

[0151] Fail-Safe Operation

[0176]

[0152] The system is configured such that obstruction of the flow restriction results in increased pressure delivered to the actuation port.

[0177]

[0153] This provides a fail-secure braking characteristic, ensuring braking capability is maintained under fault conditions.

[0178]

[0154] Removable Orifice Cartridge

[0179]

[0155] In further preferred embodiments, the actuator assembly includes a removable and interchangeable flow restriction cartridge 60 (example shown in Figure 7) configured to form all or part of the return port of the block unit or hydraulic manifold. The cartridge provides the flow restriction function for regulating return flow of hydraulic fluid to the tank unit and may be selectively installed to extend the return port or to vary the effective aperture of the return port.

[0180]

[0156] In preferred embodiments, the removable cartridge 60 is a generally elongate body configured to be received at least partially within or into the return port (second outlet port 34 in the preferred embodiment) of the block unit or hydraulic manifold 30. The cartridge has a longitudinal axis extending between an inlet end 62 and an outlet end 64, with the cartridge body defining an internal flow passage 66 extending therebetween.

[0181]

[0157] The inlet end 62 of the cartridge body is sized and shaped to fit within a corresponding bore (the return port) of the block unit 30. In one embodiment, the inlet end includes an externally threaded portion 63 along at least part of its length, the threads being complementary to internal threads formed in the return port of the block unit, thereby enabling the cartridge to be screwed into position. In alternative embodiments, the cartridge may be retained by other mechanical engagement features, including snap-fit engagement, bayonet engagement, or press-fit retention. The removable nature of the cartridge enablesreplacement, servicing, and tuning of the hydraulic characteristics without modification of the block unit, pump, or motor assembly

[0182]

[0158] The cartridge body may further include one or more keying features, such as a flat, spline, slot, pin, or asymmetric profile, configured to cooperate with a corresponding feature of the block unit. The keying feature ensures correct rotational orientation of the cartridge during installation and prevents incorrect insertion or reversal of the cartridge.

[0183]

[0159] At least one sealing interface 65 is provided on the cartridge body to prevent fluid leakage between the cartridge and the block unit. The sealing interface may include one or more circumferential grooves formed in the outer surface of the cartridge for receiving elastomeric O-rings or sealing rings. In other embodiments, the sealing interface may comprise a metal-to-metal sealing surface or a tapered seat cooperating with a corresponding surface in the block unit.

[0184]

[0160] The internal flow passage 66 of the cartridge includes a restriction section 68, typically located intermediate the inlet and outlet ends 62 and 64. The restriction section 68 is defined by a precision orifice, having a controlled diameter selected to provide the desired flow restriction. In some embodiments, the orifice is formed directly in the cartridge body. In other embodiments, the orifice is defined by a discrete insert or plate fixed within the cartridge body. The precision orifice defines a flow restriction aperture. The orifice diameter may be selected from a predetermined range to achieve desired braking characteristics, including maximum braking pressure, pressure decay rate, and dynamic response. The restriction channel / orifice 68 preferably has a length-to-diameter ratio of at least 10:1, thereby promoting laminar flow characteristics. By selecting cartridges having different orifice diameters, braking behaviour may be tailored for different vehicle masses, brake sizes, operating speeds, and application environments.

[0185]

[0161] In preferred embodiments, the cartridge defines an elongated internal channel 71 leading to the orifice. The channel geometry may be selected to promote laminar flow characteristics through the restriction 68 under normal operating conditions. In some embodiments, the hydraulic system is configured such that the Reynolds number of flow through the restriction 68 remains within a laminar regime during typical braking operation, thereby producing a stable and predictable pressure differential across a range of operating conditions.

[0186]

[0162] Upstream of the orifice 68, the cartridge 60 may define an elongated internal channel 73 of substantially uniform cross-section. The length and diameter of this channel 73 may be selected to condition the hydraulic flow and promote predictable flow behaviour through therestriction. Downstream of the orifice, the internal passage 73 may widen or taper to reduce turbulence as fluid exits the cartridge into the tank chamber.

[0187]

[0163] In preferred embodiments, the cartridge 60 further includes an integrated filtration element disposed upstream of the orifice, for example at the channel 73. The filtration element may comprise a mesh screen, perforated plate, or porous element retained within the cartridge body. The filter is positioned to intercept particulate matter before the fluid reaches the orifice, thereby reducing the risk of blockage or erosion.

[0188]

[0164] In some embodiments, the cartridge includes a directional flow feature, such as an asymmetric internal geometry or one-way flow characteristic, to ensure correct flow behaviour during pressurisation and depressurisation. In further embodiments, the cartridge may be configured to act as a pressure relief element, permitting controlled bypass or deformation under excessive pressure conditions to protect system components.

[0189]

[0165] The cartridge body may be manufactured as a single piece or as a multi-component assembly, and may be formed from metal, such as stainless steel, brass, aluminium, or another corrosion-resistant alloy. In some embodiments, portions of the cartridge may be formed from polymeric or composite materials compatible with hydraulic fluids.

[0190]

[0166] The outlet end of the cartridge is configured to discharge hydraulic fluid directly into the tank chamber of the tank unit, optionally below the normal fluid level, to reduce splashing or aeration. The overall dimensions of the cartridge are selected such that installation, removal, or replacement can be performed without disassembly of the pump, motor, or block unit.

[0191]

[0167] The cartridge-based restriction may be configured to produce a high-velocity return flow through the orifice while maintaining a defined pressure drop across the restriction. This arrangement enables clear pressure and velocity differentiation between the actuation port delivering high-pressure fluid to the braking elements and the return port delivering lower-pressure, high-velocity fluid back to the tank unit. In preferred embodiments, fluid returning through the cartridge dissipates kinetic energy within the tank unit, and the return outlet may be positioned below fluid level to minimise aeration of the hydraulic fluid.

[0192]

[0168] In preferred embodiments, the actuator assembly may be supplied with multiple interchangeable cartridges having different orifice diameters, different internal channel lengths, and different overall cartridge lengths. By selecting a cartridge from a predefined set of configurations, the effective flow restriction characteristics of the return port can be optimised or customised for a particular vehicle mass, braking system size, or operating condition. The use of cartridges with varying diameters and lengths enables fine tuning of braking pressure, pressure decay rate, and response behaviour without modification of theblock unit, pump, or motor, thereby providing a flexible and modular hydraulic control system adaptable across multiple applications.

[0193]

[0169] The removable cartridge effectively functions as an extension of the return port by effectively lengthening the return flow path and defining the flow-restricting geometry downstream of the block unit. When installed, the cartridge forms a continuation of the return port bore, with hydraulic fluid passing through the internal passage and orifice of the cartridge before entering the tank unit. In this manner, the cartridge determines the effective aperture, flow resistance, and hydraulic behaviour of the return port without requiring modification of the block unit itself.

[0194]

[0170] The use of interchangeable cartridges provides a modular hydraulic control platform that is adaptable across multiple vehicle configurations and operating environments. Braking characteristics may be adjusted or tuned simply by selecting and installing a cartridge having a different orifice diameter or internal geometry, without modification of the manifold, pump, motor, or control electronics.

[0195]

[0171] In further embodiments, the actuator assembly may incorporate diagnostic and monitoring functions associated with the cartridge and orifice. For example, the system may detect orifice erosion based on an increase in motor speed required to achieve a target braking pressure, or detect partial blockage of the orifice based on a rise in braking pressure at reduced motor speed. In such embodiments, diagnostic data may be stored locally and / or transmitted to an external system for servicing, monitoring, or fleet management purposes.

[0196]

[0172] Laminar Flow Stability

[0197]

[0173] The restriction may include an elongated channel promoting laminar flow, improving pressure stability and reducing sensitivity to fluid viscosity changes.

[0198]

[0174] Sensor and Diagnostics

[0199]

[0175] A pressure sensor may be provided within the hydraulic internal path, enabling closed-loop control and detection of wear, blockage, or degradation of the flow restriction.

[0200]

[0176] Solid-State Control

[0201]

[0177] Hydraulic pressure modulation is achieved solely through motor speed control in combination with fixed-geometry hydraulic elements, eliminating the need for solenoid valves.

[0202]

[0178] In another aspect, the invention provides an electro-hydraulic actuator assembly comprising: a hydraulic reservoir, a pump, a motor, a manifold, and a fixed-geometry flow restriction, wherein pressure is regulated by varying motor speed relative to the restriction.

[0179] In the preferred embodiment, the restriction is arranged as a bypass returning fluid to the reservoir.

[0203]

[0180] Preferably, the restriction is arranged within a delivery path.

[0204]

[0181] The disclosure also provides a braking system comprising the actuator assembly and a controller configured to regulate motor speed.

[0205]

[0182] The preferred embodiments provide one or more of the following advantages and / or additional features:

[0206] • Pressure proportional to motor speed.

[0207] • Continuous circulation during standby.

[0208] • Pre-charged hydraulic condition.

[0209] • Flow restriction governs maximum pressure.

[0210] • Flow restriction governs pressure dissipation.

[0211] • Obstruction increases braking pressure.

[0212] • Fail-secure operation.

[0213] • No loss of braking under restriction failure.

[0214] • Removable restriction element.

[0215] • Cartridge configuration.

[0216] • Threaded cartridge interface.

[0217] • Tunable cartridge.

[0218] • Cartridge filtration.

[0219] • Cartridge sealing interface.

[0220] • Serviceable cartridge.

[0221] • Orifice restriction.

[0222] • Orifice diameter range.

[0223] • Elongated channel.

[0224] • Laminar flow characteristics.

[0225] • High velocity return flow.

[0226] • Pressure / velocity differentiation.• Monolithic manifold.

[0227] • Intersecting channels.

[0228] • Junction flow split.

[0229] • Single-path bidirectional architecture.

[0230] • Shared pressurisation and depressurisation path.

[0231] • Submerged return.

[0232] • Energy dissipation in reservoir.

[0233] • Reduced aeration.

[0234] • Pressure sensor inclusion.

[0235] • Downstream sensor location.

[0236] • Closed-loop control.

[0237] • Diagnostic detection.

[0238] • Degradation detection.

[0239] • Blockage detection.

[0240] • Brushless motor.

[0241] • High-voltage operation.

[0242] • Multi-circuit braking.

[0243]

[0183] The disclosure in another aspect provides a method of regulating braking pressure via motor speed and fixed restriction, which provides fail-safe pressure increase method, and preferably a diagnostic detection method.

[0244]

[0184] In the preferred embodiment, the return path branches from the internal flow path at a junction upstream of the actuation port.

[0245]

[0185] In the preferred embodiment, the junction forms a T-shaped intersection.

[0246]

[0186] In the preferred embodiment, the flow restriction is the sole flow-regulating element in the return path.

[0247]

[0187] In the preferred embodiment, no active valve is present in the hydraulic circuit.

[0248]

[0188] In the preferred embodiment, hydraulic fluid remains in continuous motion during nonbraking conditions.

[0189] In the preferred embodiment, baseline pump operation maintains a pre-energised hydraulic state.

[0249]

[0190] In the preferred embodiment, pressure rise time is reduced by maintaining continuous flow through the return path.

[0250]

[0191] In the preferred embodiment, the removable cartridge is keyed to prevent incorrect installation.

[0251]

[0192] In the preferred embodiment, the cartridge includes a directional flow feature.

[0252]

[0193] In the preferred embodiment, the cartridge is configured to act as a pressure relief element under excessive pressure.

[0253]

[0194] In the preferred embodiment, the cartridge includes an integrated filter mesh upstream of the orifice.

[0254]

[0195] In the preferred embodiment, a Reynolds number of flow through the restriction is maintained within a laminar regime under normal operating conditions.

[0255]

[0196] In the preferred embodiment, the restriction produces a stable pressure differential across a range of fluid viscosities.

[0256]

[0197] In the preferred embodiment, the system detects orifice erosion based on increased motor speed required to achieve a target pressure.

[0257]

[0198] In the preferred embodiment, the system detects partial blockage based on pressure rise at reduced motor speed.

[0258]

[0199] In the preferred embodiment, diagnostic data is transmitted to an external system.

[0259]

[0200] In the preferred embodiment, fluid returning through the restriction dissipates kinetic energy within the reservoir.

[0260]

[0201] In the preferred embodiment, the return outlet is positioned below fluid level to minimise aeration.

[0261]

[0202] In the preferred embodiment, braking characteristics are adjusted by selecting different restriction diameters.

[0262]

[0203] In the preferred embodiment, the same manifold (block unit) is used across multiple vehicle classes.

[0263]

[0204] In the alternative embodiment, relative diameters of the actuation port and return path are reversed.

[0264]

[0205] In this alternative embodiment, higher velocity flow is delivered to the actuation port.

[0206] In the preferred embodiment, the manifold is machined from aluminium.

[0265]

[0207] In another embodiment, the manifold is formed by additive manufacturing.

[0266]

[0208] In the preferred embodiment, the junction forms a T-shaped intersection.

[0267]

[0209] The hydraulic block circuit (internal path) can also be configured in different arrangements than the T-shaped intersection where the pump flows to a single channel and then to both the orifice cartridge port and then outlet port which are connected separately downstream.

[0268]

[0210] In the preferred embodiment, pressure rise time is reduced by maintaining continuous flow through the return path.

[0269]

[0211] The actuator assembly can also operate from a stationary flow state and still achieve excellent pressure rise time response compared to a valved system.

[0270]

[0212] In a preferred embodiment, the flow restriction element is configured to direct a portion of the hydraulic flow from the pump to a reservoir, thereby forming a pressure-regulating bypass circuit. The pressure delivered to the brake actuation port is controlled by varying the speed of the pump relative to the fixed flow restriction.

[0271]

[0213] This configuration enables:

[0272] • active modulation of hydraulic pressure,

[0273] • reduced response latency due to pre-existing fluid circulation,

[0274] • simplified mechanical architecture through elimination of solenoid valves, • and improved reliability through fixed-geometry control elements.

[0275]

[0214] In alternative embodiments, the flow restriction element may be positioned in the brake delivery path, thereby providing a flow-dampening function.

[0276]

[0215] In another aspect, the hydraulic system comprises:

[0277]

[0216] • a variable-speed electric motor driving a hydraulic pump,

[0278]

[0217] • a monolithic hydraulic manifold including a junction,

[0279]

[0218] • a brake delivery port,

[0280]

[0219] • and a bypass flow path incorporating a fixed-geometry orifice.

[0281]

[0220] The orifice is positioned such that high-velocity, low-pressure fluid is diverted to a reservoir, while low-velocity, high-pressure fluid is delivered to the brake actuator.

[0221] The system operates by maintaining continuous circulation of hydraulic fluid through the bypass flow path during standby conditions, thereby establishing a pre-charged hydraulic state.

[0282]

[0222] Upon activation, the system increases pump speed, thereby increasing system pressure as a function of the interaction between pump output and the fixed restriction.

[0283]

[0223] This configuration provides substantially instantaneous pressure response at the brake actuator due to the absence of static fluid inertia.

[0284]

[0224] Fail-Safe Operation

[0285]

[0225] In one embodiment, the system is configured such that obstruction of the bypass flow restriction results in an increase in pressure delivered to the brake actuator.

[0286]

[0226] This characteristic provides a fail-secure mode, whereby failure of the pressureregulating element results in increased braking force rather than loss of braking capability.

[0287]

[0227] This contrasts with alternative configurations in which restriction failure may result in reduced or eliminated braking performance.

[0288]

[0228] Alternative Embodiment - Flow Dampening

[0289]

[0229] In an alternative embodiment, the flow restriction element is positioned within the brake delivery path between the pump and the brake actuator.

[0290]

[0230] In this configuration, the restriction functions to modulate the rate of pressure increase delivered to the brake actuator.

[0291]

[0231] This embodiment may be suited to applications requiring controlled or gradual brake engagement, including low-speed manoeuvring or autonomous vehicle control modes.

[0292]

[0232] Removable Orifice Cartridge

[0293]

[0233] In one embodiment, the flow restriction element is provided as a removable and interchangeable cartridge. The cartridge is configured to be received within a corresponding port of the hydraulic manifold and may include:

[0294] • a precision orifice,

[0295] • an integrated filtration element,

[0296] • and a sealing interface.

[0297]

[0234] The use of interchangeable cartridges enables tuning of braking characteristics for different vehicle masses and operating conditions without modification of the manifold or pump assembly. This provides a modular hydraulic control platform adaptable across multiple vehicle configurations.

[0235] Laminar Flow Control

[0298]

[0236] In one embodiment, the orifice comprises a restriction channel / orifice having a length-to-diameter ratio of at least 10:1 , thereby promoting laminar flow characteristics.

[0299]

[0237] This configuration improves pressure stability and reduces sensitivity to fluid viscosity variations across temperature ranges.

[0300]

[0238] Sensor & Diagnostic System

[0301]

[0239] The system may further comprise a pressure sensor located downstream of the pump and upstream of the brake actuator.

[0302]

[0240] The sensor provides real-time feedback to a controller configured to regulate pump speed in a closed-loop manner.

[0303]

[0241] In one embodiment, the system is configured to detect:

[0304] • erosion of the flow restriction element,

[0305] • partial or complete blockage,

[0306] • and deviations in hydraulic efficiency,

[0307]

[0242] by monitoring the relationship between pump speed and resulting pressure.

[0308]

[0243] This enables a self-diagnostic braking system capable of detecting mechanical degradation.

[0309]

[0244] Solid-State Control

[0310]

[0245] The system operates without the use of solenoid-actuated valves, and instead relies on fixed-geometry hydraulic elements and motor control. This provides a solid-state electro-hydraulic braking system, reducing mechanical complexity and failure modes associated with valve-based systems.

[0311]

[0246] Serviceability & Safety

[0312]

[0247] In one embodiment, the removable flow restriction cartridge is configured to:

[0313] • be replaceable without disassembly of the hydraulic system,

[0314] • include mechanical keying to ensure correct installation orientation,

[0315] • and optionally provide pressure relief functionality under extreme conditions.

[0316]

[0248] Whilst preferred embodiments of the present invention have been described, it will be apparent to skilled persons that modifications can be made to the embodiments described.

Claims

ClaimsThe claims defining the invention are as follows:

1. An actuator assembly comprising:a tank unit for holding hydraulic fluid;a block unit having an internal hydraulic path formed therein, the block unit having an inlet port, an actuation port, and a return port connected to the internal hydraulic path; a pump disposed within the tank unit for receiving hydraulic fluid from the tank unit, an outlet of the pump being fluidly connected to the inlet port of the block unit;a motor for driving the pump;wherein, when actuated by the motor, the pump draws hydraulic fluid from the tank unit and delivers pressurised hydraulic fluid via the actuation port to one or more braking elements and a continuous portion of hydraulic fluid returns to the tank unit through the return port.

2. The actuator assembly according to claim 1 , wherein the internal hydraulic path defines a single-path bidirectional architecture such that pressurisation and depressurisation occur through the same internal hydraulic path.

3. The actuator assembly according to claim 1, wherein the return port has a smaller effective flow area than the actuation port.

4. The actuator assembly according to claim 3, wherein the return port is formed as a fixed-geometry orifice.

5. The actuator assembly according to claim 1, wherein braking pressure delivered via the actuation port is regulated by varying a rotational speed of the motor.

6. The actuator assembly according to claim 1, wherein the return port is configured to govern a maximum attainable braking pressure for a given motor speed by controlling the proportion of hydraulic fluid returned to the tank unit during pressurisation.

7. The actuator assembly according to claim 1, wherein the return port is configured to govern a rate of pressure dissipation upon reduction or cessation of motor speed.

8. The actuator assembly according to claim 1, wherein the block unit comprises a first outlet port and a second outlet port, one of which defines the actuation port and the other of which defines the return port.

9. The actuator assembly according to claim 8, wherein pressurised hydraulic fluid is delivered to one or more brake callipers through the first outlet port and hydraulic fluid is returned to the tank unit through the second outlet port.

10. The actuator assembly according to claim 1, wherein the pump is disposed within the tank unit such that a pump inlet is submerged in hydraulic fluid during operation.

11. The actuator assembly according to claim 1, wherein the block unit forms a sealed wall of the tank unit.

12. The actuator assembly according to claim 1, wherein the block unit is free of any hydraulic valve, proportional solenoid, or switching mechanism for regulating braking pressure.

13. The actuator assembly according to claim 1, further comprising an electronic control unit configured to receive a braking demand signal and to control the motor speed in response to the braking demand signal.

14. The actuator assembly according to claim 1, wherein the pump is mounted to and mechanically coupled to the block unit.

15. The actuator assembly according to claim 14, wherein the motor is disposed on an opposite side of the block unit from the pump and is coupled to the pump via an axle extending through the block unit.

16. The actuator assembly according to claim 15, wherein the block unit is formed as a solid block having a pump side face and a motor side face, and wherein the internal hydraulic path comprises at least one internal channel formed within the block unit.

17. The actuator assembly according to claim 1, wherein the internal channel comprises a vertical channel and a horizontal channel intersecting at an intersection point.

18. The actuator assembly according to claim 17, wherein the vertical channel extends between the inlet port and one of the actuation port or return port formed at a distal end of the vertical channel.

19. The actuator assembly according to claim 18, wherein the horizontal channel extends between the intersection point and the other of the actuation port or return port formed at a distal end of the horizontal channel.

20. The actuator assembly according to claim 1, wherein the tank unit comprises an end wall and a plurality of side walls defining a hollow tank chamber, and wherein the block unit closes an open side of the tank unit.

21. The actuator assembly according to claim 1, wherein the actuation port is fluidly connected to one or more brake calliper lines for actuating brake callipers.

22. The actuator assembly according to claim 1, wherein the tank unit includes an internal hydraulic line connected to the actuation port, allowing an external brake calliper line to be connected to the actuator assembly.

23. The actuator assembly according to claim 1, wherein the return port opens directly into the tank chamber such that the return port remains submerged in hydraulic fluid during operation.

24. The actuator assembly according to claim 17, wherein the internal channels are formed as blind drilled bores sealed at their openings.

25. The actuator assembly according to claim 24, wherein the block unit is machined from aluminium or an aluminium alloy.

26. The actuator assembly according to any preceding claim, further comprising a removable cartridge attached to the return port of the block unit.

27. The actuator assembly according to claim 26, wherein the cartridge includes a hollow cartridge body having an inlet end, an outlet end, and an internal flow passage extending between the inlet end and the outlet end.

28. The actuator assembly according to claim 27, wherein the cartridge body includes a flow-restricting orifice disposed in the internal flow passage.

29. The actuator assembly according to claim 28, wherein the cartridge further includes a filtration element disposed upstream of the orifice within the internal flow passage.

30. The actuator assembly according to claim 26, wherein the cartridge is threadedly engaged with the return port of the block unit.

31. The actuator assembly according to claim 26, wherein the cartridge includes a keying feature configured to prevent incorrect orientation during installation.

32. The actuator assembly according to any preceding claim, further comprising a pressure sensor mounted to the block unit and configured to sense pressure within the internal hydraulic path.

33. The actuator assembly according to claim 32, wherein the pressure sensor is fluidly connected to the internal hydraulic path via a fourth port extending from a motor side face of the block unit to the internal hydraulic path.

34. The actuator assembly according to any preceding claim, wherein the second outlet port is disposed along a vertical channel of the internal hydraulic path below the inlet port.

35. The actuator assembly according to any preceding claim, wherein the second outlet port and the first outlet port are arranged along a common hydraulic flow path within the internal hydraulic path such that hydraulic fluid flows sequentially past the second outlet port and then to the first outlet port.

36. A method of generating and regulating hydraulic braking pressure, the method comprising:drawing hydraulic fluid from a tank unit into a pump;driving the pump using a motor to deliver hydraulic fluid into an internal hydraulic path formed in a block unit;delivering pressurised hydraulic fluid from the internal path to one or more braking elements through an actuation port formed in the block unit; andcontinuously returning a portion of the hydraulic fluid from the internal path to the tank unit through a return port formed in the block unit.

37. The method according to claim 36, wherein braking pressure is regulated by varying a rotational speed of the motor.

38. The method according to claim 36, wherein pressurisation and depressurisation of the braking circuit occur through the same internal hydraulic path within the block unit.

39. The method according to claim 36, wherein reducing or stopping the motor causes hydraulic pressure to dissipate through the return port without operation of a hydraulic valve or solenoid.

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