Patent Description:
<FIG> and <FIG> show a conventional control module <NUM> for a hydraulic system, which module <NUM> comprises a tank <NUM> for storing hydraulic fluid as well as a fluid manifold <NUM> operatively connected to the tank <NUM>. The manifold <NUM> can include various fluid distribution features, such as valves, passages and the like for controlling distribution of hydraulic fluid to various parts of the system.

The tank <NUM> is mechanically linked to the manifold <NUM>, although there is typically a physical separation between these components (e.g., by a spacer <NUM>), whilst the feet <NUM> are typically located beneath the manifold <NUM> for connecting the module <NUM> to a suitable surface or component.

It has been found that asymmetrical loads may be experienced, for example if the module <NUM> is exposed to vibrations and other types of environments. There is also a need for a shield <NUM> surrounding the tank to ensure that the module <NUM> is fireproof.

<FIG> shows the module <NUM> more schematically, and including indication of the various input and output passages <NUM> for distribution of hydraulic fluid to and from the module <NUM>. The hydraulic fluid is typically shielded from fire and other heat influences, and this can be through the use of a separate tank of fluid that surrounds a first tank.

It is desired to improve the construction of control modules such as that shown in <FIG> and <FIG> to solve the above challenges.

<CIT> discloses features of the preamble of claim <NUM>.

In accordance with an aspect of the invention there is provided a control module for a hydraulic system according to claim <NUM>.

The claimed arrangement of the tank, plurality of valves and one or more passages provides an improved control module that is more balanced due to the locating/spacing of the plurality of valves around a circumference of the tank. The valves are located between the axial ends of the tank (with respect to a longitudinal axis of the tank).

The one or more passages may extend at least partly in a circumferential direction around the circumference of the tank. This provides a better flow through the passages.

The control module further comprises a plurality of feet (e.g., four feet) configured to attach the control module to a surface. Some (e.g., two) of the plurality of feet are positioned at a first end of the tank, and others (e.g., two) of the plurality of feet are positioned at a second end of the tank, wherein the first end is opposite the second end. The 'end' referred to here is defined by the longitudinal axis of the (cylindrical) tank. This provides a more balanced control module.

The plurality of feet may be positioned such that a centre of gravity of the control module is located between the feet when the control module is attached to a surface, e.g., a substantially horizontal surface. This balances the forces associated with the control module and reduces asymmetrical loads.

The plurality of feet may be positioned such that a centre of gravity of the control module is located substantially half-way along a length and width of the control module, when the control module is attached to a surface, wherein the length is defined along the longitudinal axis of the (cylindrical) tank, and the width is defined transverse to the longitudinal axis. This provides the optimum balancing of forces for the control module.

The control module further comprises a housing, wherein at least some of the plurality of valves are formed by portions of the housing. This provides a lighter module with fewer parts. The one or more passages are formed by and within the housing, which can help reduce weight.

The housing comprises an inner cylindrical surface forming part of the tank. This combines with the passages being formed by and within the housing to provide a heat resistant structure using the fluid flow through the passages. This can avoid the need for an insulating piece around the tank, reducing weight and optimising the arrangement.

The housing is a single/unitary piece, e.g., a single piece of material, and may be formed using an additive manufacturing process. Use of an additive manufacturing process is seen as an optimised and highly efficient way of constructing the module. It has been recognised that the use of valves around the circumference and (optionally) passages extending at least partly in a circumferential direction around the circumference of the tank can be easily manufactured using an additive manufacturing process.

The plurality of valves may comprise one or more supply valves configured to supply pressurised hydraulic fluid to one or more components of the hydraulic system.

The plurality of valves may comprise one or more return valves configured to receive hydraulic fluid from one or more components of the hydraulic system.

In accordance with an aspect of the invention there is provided a hydraulic system comprising a control module as described above.

The control module may be configured to supply pressurised hydraulic fluid to one or more components of the hydraulic system.

The hydraulic system may be for an aircraft, e.g., a helicopter. The components may be aircraft (e.g., helicopter) components, such that the control module is configured to supply pressurised hydraulic fluid so as to control and/or actuate the aircraft components.

The components may include one or more (or all of) a landing gear, one or more flight control surfaces, one or more actuators, such as actuators for rotors such as the main rotor and/or tail rotor of a helicopter.

Herewith will be described various embodiments of a control module for a hydraulic system, sometimes termed a power control module (e.g., a hydraulic power control module). Such control modules comprise a tank for holding hydraulic fluid, and a number of valves and passages for controlling distribution of hydraulic fluid to various parts of the system. Systems for use with such control modules can include aerospace applications, such as aircraft (e.g., aeroplane, helicopter, or other vehicle). The hydraulic fluid in such examples may be used to control (e.g., actuate) various components, such as landing gear, flight control surfaces and the like.

In various embodiments the control modules of the present invention are configured for use with high stress environments, such as those used in aircraft, and also the control modules are configured to distribute hydraulic fluid to various different components. To do this the control modules may comprise any number of suitable valves and passages, wherein the valves may be moved or otherwise actuated by a control system to enable hydraulic fluid to control the components in question.

It has been found that additive manufacturing is particularly suitable for forming the control modules disclosed herein, in that various embodiments may require a complicated system of valves and passages that surround a hydraulic fluid tank. Additive manufacturing permits this complicated system to be manufactured more easily, especially due to the necessity in some embodiments of circumferential passageways between the various valves. This is discussed in more detail below.

<FIG> show schematically a control module <NUM> of the present invention, wherein the control module <NUM> comprises a tank <NUM> that is defined by a housing <NUM>. The tank <NUM> is for storing hydraulic fluid, which can then be distributed to a hydraulic fluid system provided in connection with the control module <NUM>.

The control module <NUM> is shown schematically in <FIG>, wherein a manifold for distributing hydraulic fluid is located circumferentially around the tank <NUM>, and forms part of the housing <NUM>. Various valves <NUM> are located around a circumference of the tank <NUM>, which form part of the manifold and are configured to distribute hydraulic fluid to the hydraulic fluid system.

As shown in more detail in <FIG>, the control module <NUM> comprises feet <NUM> that are distributed at each opposed end of the tank <NUM>, wherein the feet <NUM> are for connecting and/or attaching the control module <NUM> to a suitable surface or component. Importantly, the centre of gravity of the control module <NUM> is located between the feet <NUM> and in the direction of a longitudinal axis A of the tank <NUM>.

The control module <NUM> is provided as an integrated, single piece, so as to provide an all-in-one architecture including the tank <NUM> and various components for distributing hydraulic fluid to a hydraulic fluid system, including the valves <NUM> and other passages fluidly connecting the valves <NUM> to the tank <NUM>.

Due to the complicated nature of such a module <NUM>, including circumferential passages between the valves <NUM>, conventional manufacturing techniques may not be suitable for manufacturing the control module <NUM> as disclosed herein. As such, additive manufacturing techniques may be used that greatly simplify the manufacture of the control module <NUM> and provide this as a single piece as aforesaid.

It has been found that combining parts of the manifold for the distribution of hydraulic fluid from the tank <NUM> with the housing <NUM> means that there is hydraulic flow (e.g., continuous hydraulic flow) during use of the control module <NUM>, which assists in heat dispersion and minimises the risk of overheating of the control module <NUM>. This also eliminates the need for a fire shield located around the tank <NUM>, as is required in conventional techniques described above, which reduces mass and the number of components required for the module.

In the module <NUM> of the present invention the fire protection capability previously provided by a second tank is now provided by the hydraulic ducts, valves, etc. that naturally surround the tank <NUM>. In this way we can avoid the second tank (or similar solutions) of the conventional arrangement.

<FIG> shows a control module <NUM> according to the invention in more detail, and including various valves <NUM> that are distributed around a circumference of a hydraulic fluid tank <NUM>. The tank <NUM> is formed in part by a housing <NUM>, wherein a manifold for distributing hydraulic fluid is formed by part of the housing <NUM>.

Various fluid passages are provided between the valves <NUM>, and these may include circumferential passages fluidly connecting the valves <NUM> and/or the tank <NUM>. The use of circumferential passages is seen as beneficial, in that pressure losses can be reduced by avoiding sharp bends or intersections, and is enabled by the positioning of valves <NUM> around the circumference of the tank <NUM> as aforesaid.

<FIG> shows the fluid passages 120a, 120b of the control module <NUM> in isolation with the valves 115a, 115b. As is evident at least some (e.g., a majority) of the fluid passages 120a, 120b extend in a circumferential direction relative to a longitudinal axis of the tank <NUM>, which would be positioned within the valves 115a, 115b as shown in, e.g., <FIG> and <FIG>.

<FIG> also indicates the different types of fluid passages and valves, namely pressurised or supply valves 115a and associated fluid passages 120a, as well as return valves 115b and associated fluid passages 120b. The supply valves 115a and associated passages 120a may be configured to supply pressurised hydraulic fluid to suitable parts of the hydraulic system, for example to actuate one or more components. The components may comprise one or more aircraft (e.g., helicopter) components such as landing gear, flight control surfaces, actuators, e.g., for rotors such as a main rotor and/or tail rotor (e.g., for a helicopter), and the like.

The return valves 115b and associated passages 120b may be configured to receive hydraulic fluid from the hydraulic system, for example from one or more components. The fluid received from the return valves 115b may firstly go to the tank <NUM>, after which it may be pressurised by one or more pumps (not shown) and then supplied back to the supply valves 115a and associated passages 120a (under pressure) for forwarding on to one or more components as aforesaid.

One more pumps (not shown) may be provided, e.g., as part of the manifold, which may be configured to pressurise and/or distribute the fluid through the supply valves 115a and associated passages 120a.

<FIG> shows the fluid passages 120a, 120b and valves 115a, 115b in combination with the remainder of the housing <NUM>, to illustrate how they are distributed within the control module <NUM>. As will be appreciated, the tank <NUM> is formed in part by an inner, substantially cylindrical surface 112a of the housing <NUM>, and at least some (e.g. a majority) of the various passages 120a, 120b extend circumferentially around the cylindrical surface 112a forming part of the tank <NUM>. As noted above, this optimises the performance of the control module <NUM> by reducing pressure losses within the passages 120a, 120b between the various valves 115a, 115b caused by, e.g., sharp bends or intersections.

In addition, it can be seen that the feet <NUM> of the housing <NUM> and control module <NUM> are distributed at either axial end of the housing <NUM> (and tank <NUM>), which enhances the stability of the control module <NUM> by placing its centre of gravity between the feet <NUM> in contrast with conventional arrangements.

Claim 1:
A control module (<NUM>) for a hydraulic system, the module (<NUM>) comprising:
a tank (<NUM>) configured to store hydraulic fluid, wherein the tank (<NUM>) is substantially cylindrical and comprises a longitudinal axis;
a plurality of valves (<NUM>) fluidly connected to the tank (<NUM>) and configured to control distribution of hydraulic fluid from the tank (<NUM>) to one or more components of the hydraulic system, wherein the plurality of valves (<NUM>) are spaced around a circumference of the tank (<NUM>); and
one or more passages (<NUM>) fluidly connecting the tank (<NUM>) with at least one of the plurality of valves (<NUM>) and/or a first of the plurality of valves (<NUM>) with a second of the plurality of valves (<NUM>),
wherein the plurality of valves (<NUM>) are located axially between first and second axial ends of the tank (<NUM>) with respect to a longitudinal axis thereof, wherein the first axial end is opposite the second axial end in the direction of the longitudinal axis of the tank (<NUM>),
wherein the control module (<NUM>) further comprises a housing (<NUM>),
wherein at least some of the plurality of valves (<NUM>) are formed by portions of the housing (<NUM>),
wherein the one or more passages (<NUM>) are formed by and within the housing (<NUM>),
wherein the housing (<NUM>) is a single piece of material,
characterised in that:
the control module further comprises a plurality of feet (<NUM>; <NUM>) configured to attach the control module (<NUM>) to a surface, wherein some of the plurality of feet (<NUM>) are positioned at the first axial end of the tank (<NUM>),
and others of
the plurality of feet (<NUM>) are positioned at the second axial end of the tank (<NUM>); and
the housing comprises an inner cylindrical surface forming part of the tank.