A hydraulic centre joint

Abstract

A hydraulic centre joint (swivel joint) 100 comprising an outer body 102, an inner body 104, a first passage P1 and a second passage P2. The inner body is arranged at least partially within the outer

Description

FIELD The present teachings relate to a hydraulic centre joint for a hydraulic system, a working machine including a hydraulic centre joint, and a tiltrotator including a hydraulic centre joint. BACKGROUND A hydraulic centre joint, sometimes also known as a swivel joint, rotary coupling or rotary joint, is a device which enables fluid (e.g. a hydraulic fluid such as oil) to be transported between two parts of a machine that are rotatable relative to each other about a rotational axis. For example, a centre joint may be used between an undercarriage and a rotatable superstructure of a working machine (e.g. a slewing excavator or a roto telehandler), or between a working machine's boom and an implement rotatably mounted to the boom (e.g. in a tiltrotator). A centre joint generally includes an outer body and an inner body rotatable relative to each other about a rotational axis, and one or more distinct passages for transporting a fluid. Each passage includes a first port in the outer body, and a second port in the inner body. The centre joint is configured such that fluid is permitted to pass along each passage between the first and second ports for a range of relative rotational positions of the outer and inner bodies. Therefore, fluid can be transported between two relatively rotatable parts of a machine via the first and second ports. Typically, the inner body is formed from a solid block of metal, in which bores are machined to form portions of the passages. As such, the inner body includes a high volume of material, which increases the mass and the cost to manufacturer of the centre joint. Moreover, such an inner body limits the maximum size and number of the passages of the centre joint. In hydraulic control systems including such a centre joint, this can lead to high fluid pressures in the passages, which can limit control output. The present teachings seek to overcome or at least mitigate one or more problems associated with the prior art. SUMMARY The present teachings provide a hydraulic centre joint of claim 1 according to the appended claims. A first aspect of the teachings provides a hydraulic centre joint comprising an outer body. The hydraulic centre joint may comprise an inner body arranged at least partially within the outer body and rotatable relative to the outer body about a rotational axis. The hydraulic centre joint may comprise a first passage defining a fluid flow path between a first outer body port on the outer body and a first inner body port on the inner body. The first passage may comprise a first passage portion in the inner body. The hydraulic centre joint may comprise a second passage defining a fluid flow path between a second outer body port on the outer body and a second inner body port on the inner body. The second passage may comprise a second passage portion in the inner body. The first passage and the second passage may be configured such that fluid can travel between the respective outer body port and inner body port for a range of relative rotational positions of the outer and inner bodies. The first passage portion may be nested within the second passage portion. Advantageously, nesting the first passage portion within the second passage portion may help to increase the size and number of passages through the centre joint, without increasing the size of the inner body. The second passage portion may comprise a cavity defined by the inner body. Advantageously, such a configuration may enable the area of the second passage portion to be increased. The inner body may comprise a cylindrical wall which is rotatably and sealably received within the outer body. The cylindrical wall may have an inner surface which defines the cavity. Advantageously, such a configuration may help increase the size of the cavity and thus of the second passage portion. The cylindrical wall may be tubular. The cylindrical wall may have a substantially uniform thickness in a radial direction relative to the rotational axis. The first passage may pass radially through the cylindrical wall with respect to the rotational axis. The first passage portion may comprise a pipe within the cavity. The pipe may comprise one or more swept bends along its length. Advantageously, swept bends may help inhibit turbulence in fluid in the pipes, and thus help reduce related pressure losses. The second passage portion may have a greater flow cross-sectional area relative to the first passage portion. Advantageously, providing the second passage portion with a greater cross-sectional area compared to the first passage portion enables fluid to flow through the second passage portion at a greater flow rate and / or lower pressure relative to the first passage portion. The second passage may be configured to enable fluid to flow therealong in a direction counter to fluid flowing along the first passage. Advantageously, such a configuration enables the second passage to be used as a fluid return passage, helping to relieve back pressure in the centre joint. Each passage may comprise an annular channel defined between the outer body and inner body and extending at least partially around the rotational axis. Such a configuration enables hydraulic fluid to travel between the inner and outer body ports for a range of relative rotational positions of the inner and outer bodies. The annular channels of respective passages may be distributed along an elongate length of the centre joint. Adjacent channels may be fluidly isolated from each other. The second passage may comprise a plurality of inner channel ports in the inner body fluidly connecting the second inner body port with the respective channel. The inner channel ports may be adjacent said channel. Advantageously, such a configuration may help to reduce pressure losses / increase flow rates of fluid through the second passage, via increasing the flow-cross-sectional area of the second passage, and / or via reducing the length of the flow path between the inner body port and outer body port of the second passage for a range of relative rotational positions of the outer and inner bodies. The plurality of inner channel ports may be arranged circumferentially around the rotational axis. Advantageously, such a configuration may help to reduce the length of the flow path between the inner body port and outer body port of the second passage for a range of relative rotational positions of the outer and inner bodies. The plurality of inner channel ports may be substantially equally spaced along a circumference of the inner body. The second passage may comprise an inner channel port in the inner body fluidly connecting the second inner body port with the respective channel. Said inner channel port may be adjacent said channel. Said inner channel port may comprise an elongate slot having a length which extends circumferentially with respect to the rotational axis. Advantageously, such a configuration may help to reduce pressure losses / increase flow rates of fluid through the second passage. The first passage may comprise an inner channel port in the inner body fluidly connecting the first inner body port with the respective channel. Said inner channel port may be adjacent said channel. The first passage portion may join the first inner body port and inner channel port. The first passage portion may be substantially U-shaped or L-shaped. Such a shape may help to reduce the length of the first passage portion. The second passage may comprise an inner channel port in the inner body fluidly connecting the second inner body port with the respective channel. Said inner channel port may be adjacent said channel. The second passage portion may join the second inner body port and inner channel port. The hydraulic centre joint may comprise a plurality of first passages. Advantageously, including a plurality of first passages increases the number of distinct passages through the centre joint, which enables more fluid to be routed via the centre joint for an increasing number of functions. Part of each first passage portion may extend substantially parallel to the rotational axis. Advantageously, such a configuration may help to increase the maximum packing density of first passage portions within the inner body. The first passage portions may be arranged circumferentially around the rotational axis. The hydraulic centre joint may comprise a plurality of second passages. Each second passage may comprise a second passage portion with a corresponding first passage portion nested therein. Advantageously, including a plurality of second passages increases the number of distinct passages through the centre joint, which enables more fluid to be routed via the centre joint for an increasing number of functions. Each second passage portion may have a greater flow cross-sectional area relative to each first passage portion. Advantageously, providing the second passage portions with greater cross-sectional areas compared to the first passage portions enables fluid to flow through the second passages portion at a greater flow rate and / or lower pressure relative to the first passage portions. The hydraulic centre joint may comprise two or more first passages and / or two or more second passages. Each passage may comprise an annular channel defined between the outer body and inner body and extending at least partially around the rotational axis. Each passage may comprise an inner channel port in the inner body fluidly connecting the respective inner body port with the respective channel. Each passage may comprise an outer channel port in the outer body fluidly connecting the respective outer body port with the respective channel. In a predetermined rotational position of the inner and outer bodies, the corresponding inner channel port and outer channel port of two or more of the passages may be substantially aligned. Advantageously, such a configuration helps to reduce pressure losses in fluid moving along the passages by reducing the length of the flow path between the corresponding inner body port and outer body port in the predetermined rotational position. Said two or more passages may comprise two or more second passages. Advantageously, such a configuration helps to reduce pressure losses in fluid moving along the second passages by reducing the length of the flow path between the corresponding inner body port and outer body port in the predetermined rotational position. The second passage may be in fluid communication with two or more second inner body ports in the inner body, and / or two or more second outer body ports in the outer body. Advantageously, such a configuration helps to reduce pressure losses in fluid moving along the second passage. The inner body may comprise a conduit extending substantially parallel to the rotational axis for routing a cable through the centre joint. A second aspect of the teachings provides a working machine comprising the centre joint of the first aspect. The working machine may comprise a ground engaging propulsion structure, an undercarriage supported on the ground engaging propulsion structure, and a superstructure rotatably mounted to the undercarriage. One of the inner and outer bodies may be substantially fixed relative to the undercarriage and the other may be substantially fixed relative to the superstructure. The inner channel ports may be aligned with the corresponding outer channel ports when the working machine is in a travelling configuration (e.g. when a fore-aft axis of the superstructure and a fore-aft axis of the undercarriage are substantially parallel). The working machine may comprise a hydraulic system including first and second hydraulic actuators. The first and second actuators may be in a first machine portion of the working machine. The hydraulic system may be configured to supply hydraulic fluid from a second machine portion of the working machine to each actuator via one of the passages of the centre joint, and return hydraulic fluid from each actuator to the second machine portion via a different one of the passages. The hydraulic system may be switchable between: a first mode, in which hydraulic fluid is supplied to, or returned from, the first hydraulic actuator via the first passage; and a second mode, in which hydraulic fluid is supplied to, or returned from, the second hydraulic actuator via said first passage. Advantageously, the hydraulic system may enable hydraulic fluid to be selectively supplied to or returned from either the first or second hydraulic actuator at a reduced pressure. A third aspect of the teachings provides a tiltrotator comprising the centre joint of the first aspect. The tiltrotator may comprise a first body comprising an arm mounting arrangement configured to be connectable to a working arm of a working machine, a second body pivotally mounted to the first body so as to be capable of tilting about a first axis, and a third body rotatably mounted to the second body so as to be rotatable about a second axis. The second axis may be arranged at an angle to the first axis. The third body may comprise an implement mounting arrangement configured to be connectable to a working implement. One of the inner and outer bodies may be substantially fixed relative to the second body and the other may be substantially fixed relative to the third body. BRIEF DESCRIPTION OF DRAWINGS Embodiments will now be described by way of example only with reference to the accompanying figures, in which: Figure 1 is a side view of a working machine according to an embodiment; Figure 2 is an isometric view of a centre joint of the working machine of Figure 1 according to an embodiment; Figure 3 is a view along section A-A in Figure 2 in which an inner body of the centre joint is shown in phantom; Figure 4 is an isolated view of the inner body of the centre joint shown in Figure 3; Figure 5 is an isolated isometric view of the inner body of the centre joint of Figure 2; Figure 6 is a view along section B-B in Figure 4; Figure 7 is an isometric view of an assembly of the centre joint of Figure 2 and a valve block; Figure 8 is an isometric view of a centre joint of the working machine of Figure 1 according to an embodiment; Figure 9 is an isolated isometric view of an inner body of the centre joint of Figure 8; Figure 10 is a view along section C-C in Figure 9; Figure 11 is a view along section D-D in Figure 9; Figure 12 is an isometric view of a hydraulic control system including the centre joint of Figure 8; Figure 13a is a schematic representation of the working machine of Figure 1 including a hydraulic control system in a first mode of operation; Figure 13b is a schematic representation of the working machine of Figure 1 in which the hydraulic control system is in a second mode of operation; and Figure 14 is an isometric view of a tiltrotator according to an embodiment. DETAILED DESCRIPTION In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of various embodiments and the teachings. However, those skilled in the art will understand that: the present teachings may be practiced without these specific details or with known equivalents of these specific details; that the present teachings are not limited to the described embodiments; and, that the present teachings may be practiced in a variety of alternative embodiments. It will also be appreciated that well known methods, procedures, components, and systems may not have been described in detail. References to vertical and horizontal in the present disclosure should be understood to be in relation to the machine when stood on horizontal ground in a non-working condition. Figure 1 shows a side view of a working machine 10 including first and second portions 10a, 10b rotatable relative to each other about a rotational axis R. The working machine 10 shown in Figure 1 is a slew excavator. However, in alternative embodiments (not shown), the working machine 10 may instead be a rotating telescopic handler (i.e. roto telehandler), or a mobile slewing crane, for example. In the illustrated embodiment, the first portion 10a includes a superstructure 12 and a working arm 16. The second portion 10b includes an undercarriage 13, a ground-engaging propulsion structure 14 and a dozer blade 15. The superstructure 12 is rotatably mounted to the undercarriage 13 so as to be rotatable relative thereto about the rotational axis R. In some embodiments, the superstructure 12 may be capable of pivoting about the rotational axis R through 360 degrees relative to the undercarriage 13. The superstructure 12 may include a cab 12a for an operator, and an engine compartment 12b. In the illustrated embodiment, the working arm 16 is mounted to the superstructure 12 so as to be movable relative thereto. The undercarriage 13 is supported on the ground-engaging propulsion structure 14. In Figure 1, the ground-engaging propulsion structure 14 includes a pair of continuous tracks. However, in alternative embodiments, the ground-engaging structure 14 may instead include, for example, a plurality of wheels (e.g. each including a ground-engaging tyre). The undercarriage 13 includes a horizontal undercarriage fore-aft axis Fl, and the superstructure 12 includes a horizontal superstructure fore-aft axis F2. The undercarriage fore-aft axis Fl is aligned with the forward travelling direction of the undercarriage 13. The superstructure fore-aft axis F2 is aligned with the forward viewing direction of an operator in the cab 12a. In Figure 1, the undercarriage fore-aft axis Fl is substantially parallel to the superstructure fore-aft axis F2. As such, an operator in the cab 12a is facing in the forward travelling direction of the working machine 10, and so the working machine 10 may be said to be in a travelling configuration. The dozer blade 15 is mounted to the undercarriage 13, and is pivotable relative thereto about a lateral axis of the working machine 10; i.e. an axis substantially perpendicular to both the rotational axis R and a fore-aft axis of the working machine 10. The working machine 10 includes a hydraulic control system 20 for controlling movement of the working machine 10. In the illustrated embodiment, the hydraulic control system 20 is configured to control movement of: the working arm 16 relative to the superstructure 12; the superstructure 12 relative to the undercarriage 13; the ground-engaging propulsion structure 14 relative to the undercarriage 13; and the dozer blader 15 relative to the undercarriage 13, via suitable hydraulic actuators (e.g. one or more hydraulic motors, one or more hydraulic rams etc.). The hydraulic control system 20 includes a reservoir 22 for hydraulic fluid (e.g. oil), and a pump 24 in the first portion 10a (e.g. located in the engine compartment 12b). The pump 24 pumps hydraulic fluid from the reservoir 22 to the hydraulic actuators for controlling movement of the working machine 10 (e.g. via one or more valve blocks for controlling the flowrate of hydraulic fluid supplied to each actuator). The hydraulic control system 20 includes a hydraulic centre joint 100, 100' for routing hydraulic fluid between the first portion 10a and the second portion 10b. For example, hydraulic fluid may be pumped from the reservoir 22 in the first portion 10a to one or more hydraulic actuators in the second portion 10b via the centre joint 100, 100'. Hydraulic fluid may be returned from the one or more hydraulic actuators in the second portion 10b to the reservoir 22 in the first portion 10a via the centre joint 100, 100'. In Figure 1, the centre joint 100, 100' is located at the swivel joint between the superstructure 12 and the undercarriage 13. Figure 2 shows an isometric view of the centre joint 100 according to a first embodiment, and Figure 3 shows a view along section A-A in Figure 2. The centre joint 100 includes an outer body 102 and an inner body 104 rotatable relative to each other about the rotational axis R. The inner body 104 is arranged at least partially within the outer body 102. In Figure 3, the inner body 104 is shown in phantom for clarity. The centre joint 100 includes opposing first and second axial ends 100a, 100b. In the following, references to "axial", "radial" and "circumferential" are used with respect to the rotational axis R, unless stated otherwise. In the illustrated embodiment, the inner body 104 is substantially cylindrical. The outer body 102 includes a plurality of outer body ports 106. The inner body 104 includes a plurality of inner body ports 108. The centre joint 100 includes a plurality of distinct passages for transporting a fluid. Each passage defines a fluid flow path between one of the outer body ports 106 and one of the inner body ports 108. As discussed more below, each passage is configured such that fluid can travel between the respective outer body port 106 and inner body port 108 for a range of relative rotational positions of the outer and inner bodies 102, 104. Each passage includes an annular channel 110 defined between the outer body 102 and the inner body 104. Each channel 110 extends at least partially around the rotational axis R. Each passage Pl, P2 is configured such that fluid travels between the respective outer body port 106 and inner body port 108 via the channel 110. Each channel 110 is configured to maintain fluid communication between the corresponding outer and inner body ports 106, 108 for at least a range of relative rotational positions of the outer and inner bodies 102, 104 about the rotational axis R. Hence, the centre joint 100 enables fluid to be transported between the first and second portions 10a, 10b of the working machine 10 via the outer and inner body ports 106, 108 (e.g. the first portion 10a of the working machine 10 may include the outer ports 106, and the second portion 10b may include the inner ports 108, or vice versa). In alternative embodiments (not shown), each channel 110 may be partially annular (e.g. arc-shaped), and thus may only maintain fluid communication between the corresponding outer and inner body ports 106, 108 for a range of relative rotational positions of the outer and inner bodies 102, 104 (e.g. of less than 360 degrees). Each passage includes an inner channel port 114 in the inner body 104 fluidly connecting the respective inner body port 108 with the respective channel 110. Each inner channel port 114 is adjacent the respective channel 110. Each passage includes an outer channel port 112 in the outer body 102 fluidly connecting the respective channel 110 with the outer body port 106. Each outer channel port 112 is adjacent the respective channel 110. As such, fluid travels along each passage in sequence from the inner body port 108 to the inner channel port 114, to the channel 110, to the outer channel port 112, to the outer body port 106, and vice versa. For each passage, the outer and inner channel ports 112, 114 remain adjacent to and in fluid communication with the respective channel 110 as the outer and inner bodies 102, 104 rotate relative to each other about the rotational axis R. The plurality of channels 110 are arranged along an elongate length of the centre joint 100. In the illustrated embodiment, the channels 110 are spaced from each along the rotational axis R. In the illustrated embodiment, adjacent channels 110 are fluidly isolated from each other via sealing members 116 (e.g. O-rings), but may be fluidly isolated from each other via any suitable means in alternative embodiments. Each channel 110 is defined between the outer and inner bodies 102, 104 in a radial direction, and between opposed sealing members 116 in the axial direction, with respect to the rotational axis R. Adjacent channels 110 may be axially separated via one or more of the sealing members 116. In the illustrated embodiment, the outer body ports 106 of each passage includes first and second outer body ports 106a, 106b. Each first outer body port 106a is arranged at the first axial end 100a of the centre joint 100. The outer channel ports 112 are axially separated from the first outer body ports 106a. Each first outer body port 106a is connected to the corresponding outer channel port 112 via a conduit 118 in the outer body 102 (shown schematically in Figure 2). In the illustrated embodiment, each conduit 118 is formed as a bore machined in the outer body 102. Each second outer body port 106b is on a circumferential face 102b of the outer body 102, and is substantially aligned with the corresponding outer channel port 112. In Figure 2, the centre joint 100 is configured to transport fluid between the first outer body ports 106a and the inner body ports 108 only, and the second outer body ports 106b are each closed by a closure 120. The centre joint 100 may be alternatively configured to transport fluid between the second outer body ports 106b and the inner body ports 108 only, or both the first and second outer ports 106a, 106b and the inner body ports 108. The plurality of passages includes a plurality of first passages Pl, and a second passage P2. Each first passage Pl includes a first passage portion 126 in the inner body 104. The second passage P2 includes a second passage portion 124 in the inner body 104. Each first passage portion 126 is nested within the second passage portion 124. Advantageously, nesting the first passage portions 126 within the second passage portion 124 may help to increase the size and number of passages Pl, P2 through the centre joint 100, without increasing the size of the inner body 104. In alternative embodiments (not shown), the centre joint 100 may instead include a single first passage Pl. With further reference to Figure 4, the second passage portion 124 includes a cavity 124 defined by the inner body 104. Each first passage portion 126 includes a pipe 126 arranged within the cavity 124. The inner body 104 includes a cylindrical wall 130 which is rotatably and sealably received within the outer body 102. The cylindrical wall 130 includes an inner surface 131 which defines the cavity 124. In the illustrated embodiment, the cylindrical wall 130 is substantially tubular. The cylindrical wall 130 has a substantially uniform thickness in a radial direction relative to the rotational axis R, but may have a non-uniform thickness in alternative embodiments. Each inner channel port 114 passes radially through the cylindrical wall 130. As such, each first passage Pl and each second passage P2 passes radially passes radially through the cylindrical wall 130. With reference to Figure 4, which shows the cross-section of the inner body 104 shown in Figure 3 isolated, each pipe 126 joins (i.e. extends between) the respective inner body port 108 and the respective inner channel port 114; i.e. one end of each pipe 126 is adjacent the corresponding inner channel port 114, and an opposite end is adjacent the corresponding inner body port 108. Likewise, the cavity 124 joins the respective inner body portl08 and inner channel port 114. With reference to Figure 5, which shows an isolated isometric view of the inner body 104, the second passage P2 includes a plurality of inner channel ports 114. The inner channel ports 114 of the second passage P2 are arranged circumferentially around the rotational axis R. For example, the inner channel ports 114 of the second passage P2 may be substantially equally spaced along a circumference of the inner body 104. In alternative embodiments (not shown), the second passage may include only a single inner channel port 114. In the illustrated embodiment, the inner channel ports 114 of the first passages Pl are arranged circumferentially around the rotational axis R. With reference to Figure 6, which shows a view of the inner body 104 along section B-B in Figure 4, the second passage P2 is in fluid communication with two inner body ports 108, which enables fluid to flow along the second passage P2 at a greater flow rate and / or lower pressure. In alternative embodiments (not shown), the second passage may be in fluid communication with one or more than two inner body ports 108. Additionally or alternatively, the second passage may be in fluid communication with include one, two, or more than two outer body ports 106. As shown in Figure 4, fluid travels through the cavity 124 predominantly in a flow direction F (represented by a dotted double arrow in Figure 4), which is substantially parallel to the rotational axis R. Figure 6 shows that the cavity 124 has a greater flow cross-sectional area (i.e. normal to the predominant flow direction F) relative to each of the pipes 126. As such, fluid can flow through the cavity 124 at a greater flow rate and / or lower pressure relative to the pipes 126, thus helping to reduce back pressure in the hydraulic control system 20 when the second passage P2 is used as a hydraulic fluid return line to the reservoir 22. In such embodiments, the second passage P2 is configured to enable fluid to flow therealong in a direction counter to fluid flowing along the first passages Pl. As shown in Figure 6, the pipes 126 are arranged circumferentially around the rotational axis R, but may have any suitable arrangement in alternative embodiments. With reference to Figure 4, part of each pipe 126 is substantially parallel to the rotational axis R. In the illustrated embodiment, said part includes a tubular potion 126a of each pipe 126 interposed between opposite ends of the pipe 126. In alternative embodiments (not shown), each pipe 126 may have any suitable shape. In the illustrated embodiment, the inner body ports 108 and inner channel ports 114 are substantially perpendicular to the rotational axis R. As such, each pipe 126 includes two swept bends 126b. Each swept bend 126b is between one of the ports 108, 114 and the tubular portion 126a. Advantageously, swept bends, e.g. as opposed to sharp bends, may help inhibit turbulence in the pipes 126, and thus help reduce related pressure losses. In alternative embodiments (not shown), one or more of the pipes 126 may include only one or more than two swept bends along their length. In the illustrated embodiment, each pipe 126 is substantially U-shaped. In some embodiments, at least one (e.g. each) pipe may be substantially L-shaped (e.g. in an embodiment in which the inner body ports 108 are arranged at the second axial 100b end of the inner body 104 so as to extend parallel to the rotational axis R). In the illustrated embodiment, each inner body port 108 includes an adaptor 108b for connecting the port 108 to an external pipe. In alternative embodiments (not shown), each outer body port 106 may additionally or alternatively include an adaptor. In the illustrated embodiment, the inner body 104 includes a conduit 128 extending substantially parallel to the rotational axis R. The conduit 128 may be used for routing one or more (e.g. electric) cables through the centre joint 100. In the illustrated embodiment, the inner body 104 is formed from the cylindrical wall 130, and a pair of end caps 132, which together define the cavity 124. The cylindrical wall 130 is concentric with the rotational axis R (i.e. a longitudinal axis of the cylindrical wall 130 is aligned with the rotational axis R). The end caps 132 are searingly mounted to opposing axial ends of the cylindrical wall 130 so as to enclose the cavity 124. In the illustrated embodiment, the cylindrical wall 130, the end caps, 132, the outer body 102, and the pipes 126 are formed from a metal (e.g. foregoing the same metal, such as steel, or two or more different metals). In alternative embodiments (not shown), one or more of these may be formed from any suitable non-metallic material. The cylindrical wall 130 may be formed via one or more of: a metal drawing process, a casting process, a machining process, an additive manufacturing process, and a forging process. The end caps 132 may be mounted to the cylindrical wall 130 via a metal joining process (e.g. welding), a bonding process, or via one or more fasteners. Alternatively, the cylindrical wall 130 and end caps 132 may be formed as a solid monolithic piece of material (e.g. via an additive manufacturing process). The pipes 126 may be mounted to the cylindrical wall 130 via a metal joining process, such as welding (e.g. at the interface between the pipes 126 and the corresponding apertures for the inner body ports 108 and inner channel ports 114). The conduit 128 may be mounted to the end caps 132 via a metal joining process. Alternatively, if non-metallic materials are used, the pipes 126 and / or conduit 128 may be mounted via any suitable process (e.g. bonding). With reference to Figure 3, the outer body 102 includes a central bore 134 aligned with the rotational axis R, which is configured to receive the inner body 104 therein. The central bore 134 may be formed via a drilling process. An inner surface of the outer body 102 includes a plurality of first recesses 136, each defining one of the channels 110. Said inner surface includes a plurality of narrower second recesses 138 for receiving the sealing members 116. The first and / or second recesses 136, 138 may be formed via a casting process and / or machining process (e.g. CNC machining). For example, the bore 134 and recesses 136, 138 may be formed via drilling and machining a solid block of material (e.g. a metal, such as steel). In alternative embodiments, the outer body 102 may be formed via one or more of: a casting process, a machining process, and an additive manufacturing process. Turning to Figure 4, a first axial end portion 104a of the inner body 104 includes an annular groove 139, which in the illustrated embodiments is in one of the end caps 132. Turning to Figure 3, the inner body 104 includes an annular shoulder 140 towards the second axial end 100a of the centre joint 100. The inner ports 108 are axially outboard of the annular shoulder 140. To assemble the centre joint 100, a first washer 142 is received on the inner body 104 until it abuts against the shoulder 140. The first axial end 100a of the inner body 104 is then received within the bore 134 of the outer body 102 until the first washer 142 abuts against the second axial end 100b of the outer body 102 and the first axial end portion 104a projects from the first axial end 100a of the outer body 102, as shown in Figure 3. A second washer 144 is then received on the first axial end portion 104a. A fastener 148, such as a circlip for example, is then received on the first axial end portion 104a, over the second washer 144, so as to axially lock the outer and inner bodies 102, 104 together, whilst enabling relative rotation therebetween about the rotational axis R. Figure 7 shows an exemplary embodiment of an assembly 200 of the centre joint 100 and a valve block 202 of the hydraulic control system 20. The valve block 202 is configured to control the flow of hydraulic fluid flowing through one or more of the passages Pl, P2 of the centre joint 100. In the illustrated embodiment, the valve block 202 is mounted to the outer body 102 so as to be fixed relative thereto about the rotational axis R. As such, the inner body 104 is rotatable relative to the valve block 202. The valve block 202 is in fluid communication with one or more of the outer body ports 106 (e.g. via suitable piping). In alternative embodiments (not shown), the valve block 202 may be mounted to the inner body 102. The valve block 202 is configured to control one or more of the hydraulic actuators of the hydraulic control system 20 via controlling the flow of fluid through the centre joint 100. The valve block 202 and the outer body 102 may be fixed relative to the first portion 10a, and the inner body 104 may be fixed relative to the second portion 10b, about the rotational axis R, or vice versa. Figures 8 to 11 show a second embodiment of the centre joint 100'. Features common with the centre joint 100 of Figures 1 to 7 share common reference numerals with those of the second embodiment having a ' suffix, and a description of which shall not be repeated for brevity. Unless stated otherwise, the centre joint 100' of Figures 8 to 11 may share any of the features described above in relation to the centre joint 100 of Figures 1 to 7, and vice versa. The centre joint 100' includes an outer body 102' and an inner body 104' rotatable relative to each other about a rotational axis R. Similar to the first embodiment, the centre joint 100' includes a plurality of distinct passages Pl, P2 for transporting a fluid. Each passage includes: an outer body port 106' in the outer body 102', an inner body port 108' in the inner body 104', and a channel (not shown) between the outer body 102' and the inner body 104'. In contrast to the first embodiment, the centre joint 100' includes a plurality of second passages P2. Each first passage Pl includes a first passage portion 126', in the inner body 104', which includes a pipe 126' in the illustrated embodiment. Each second passage P2 includes a second passage portion 124' in the inner body 104'. Figure 9 shows an isometric view of the inner body 104' along with a number of outer body ports 106' of the second passages P2 isolated from the remainder of the outer body 102'. Figure 10 is a view along section C-C shown in Figure 9 without the outer body ports 106' of the second passages P2. Figure 11 is a view along section D-D shown in Figure 9. As shown in Figure 11, the inner body 104' includes a plurality of separate cavities 124'. Each second passage portion 124' includes one of the cavities 124'. Each pipe 126' is nested within one of the cavities 124'. Each cavity 124' includes one pipe 126'therein, but may include zero or more than one pipe 126' in alternative embodiments. Each cavity 124' is defined by the cylindrical wall 130' of the inner body 104' and an internal wall structure 190 connected to the cylindrical wall 130'. In the illustrated embodiment, the cavities 124' are manufactured via drilling and machining a solid block of material, but may be formed via any suitable process (e.g. additive manufacturing). Advantageously, having multiple second passages P2 increases the total number of distinct passages through the centre joint 100', which enables more fluid to be routed via the centre joint 100'for an increasing number of functions. In the illustrated embodiment, the centre joint 100' includes four second passages P2, but may includes two, three, or more than four second passages P2 in alternative embodiments. As is clear from Figure 11, each cavity 124' has a greater flow cross-sectional area relative to each of the pipes 126'. Hence, compared to the first embodiment, the centre joint 100' has four larger flow capacity second passages P2 and four smaller flow capacity first passages Pl. Similar to the first embodiment, each passage Pl, P2 includes an inner channel port 114' and an outer channel port 106'. In the illustrated embodiment, the outer channel ports 106' of the second passages P2 correspond to the respective outer body ports 106', but in alternative embodiments, said outer channel ports may be spaced from the corresponding outer body ports, similar to the first embodiment. In a predetermined rotational position of the inner and outer bodies 104', 102', the corresponding inner channel ports 114' and outer channel ports 106' of all of the second passages P2 are substantially aligned. Figure 9 shows the inner channel ports 114'aligned with the corresponding outer channel ports 106' for two of the second passages P2. By "substantially aligned" it is intended to mean that fluid can pass through both the inner and outer channel ports 114', 106' of a passage without substantially changing flow direction. Advantageously, such a configuration helps to reduce pressure losses in fluid moving along each second passage P2 when the outer and inner bodies 102', 104' are in the predetermined relative position. In alternative embodiments (not shown), the inner channel ports 114' and corresponding outer channel ports 106' of only two or more of the second passages P2 may be substantially aligned in the predetermined relative position. In the illustrated embodiment, the inner channel ports 114' and outer channel ports 106' of two of the first passages Pl are substantially aligned in the predetermined relative position, but more (e.g. all) or less (e.g. none) may be substantially aligned in alternative embodiments (not shown). In some embodiments, the inner channel ports 114' and outer channel ports 106' of two or more of the first passages Pl may be substantially aligned in a different predetermined relative position of the outer and inner bodies 102', 104' relative to the second passages P2. In an exemplary embodiment, in which the working machine 10 shown in Figure 1 includes the centre joint 100', one of the outer and inner bodies 102', 104' may be substantially fixed relative to the undercarriage 13 and the other of the outer and inner bodies 102', 104' substantially fixed relative to the superstructure 12. With reference to Figure 12, the working machine 10 includes two hydraulic motors 300 in the second portion 10b of the working machine 10, each motor 300 for driving one of the tracks of the ground-engaging propulsion structure 14. Hydraulic fluid is supplied to each motor 300 from the reservoir 22 in the first portion 10a of the working machine 10 via one of the second passages P2 and a first hose 302 connected to the corresponding outer body port 106'. Hydraulic fluid is returned to the reservoir 22 from each motor 300 via a different one of the second passages P2 and a second hose 303 connected to the corresponding outer body port 106'. As such, all four second passages P2 are used to supply hydraulic fluid to, or return hydraulic fluid from, the motors 300. It will be appreciated that the hydraulic motors require relatively large flowrates of hydraulic fluid when operated compared to auxiliary devices of the machine 10 (such as the dozer blade 15 for example), and so using the larger capacity second passages P2 to transport hydraulic fluid to / from the motors 300 helps to reduce pressure losses and thus improves efficiency of operation of the motors 300. During operation, it is common for hydraulic fluid to leak between an output shaft and housing of the motors 300. Each motor 300 includes a casing 300a to collect the leaked hydraulic fluid. In the illustrated embodiment, two of the first passages Pl are used for draining and returning the leaked hydraulic fluid from the casings 300a to the reservoir 22 via third hoses 305. A further two of the first passages Pl are used to transport a hydraulic fluid for changing a gear ratio of each motor 300 via fourth hoses 308 (e.g. via a pilot operated valve in each motor 300). It will be appreciated that relatively lower flowrates are required for drainage and gear changing relative to that required for operating the motors 300. In alternative embodiments (not shown), one or more of the first passages Pl may be used to supply hydraulic fluid to, or return hydraulic fluid from, one or more auxiliary actuators each configured to drive an auxiliary device of the working machine 10 (e.g. a work implement such as the dozer blade 15, or a retractable stabiliser leg); i.e. actuators generally requiring lower flowrates of hydraulic fluid relative to the motors 300. The centre joint 100' may be configured such that the inner channel ports 114' and outer channel ports 106' of the second passages P2 are substantially aligned when the working machine is in a travelling configuration (e.g. when the undercarriage fore-aft axis Fl and the superstructure fore-aft axis F2 are substantially parallel). As such, pressure losses in hydraulic fluid moving to / from the motors via the centre joint 100' are reduced when the working machine 10 is travelling. Additionally, or alternatively, the inner channel ports 114' and outer channel ports of two or more of the first passages Pl may be substantially aligned in the travelling configuration. With reference to Figure 9, the inner channel port 114' of each second passage P2 includes an elongate slot, having a length which extends circumferentially with respect to the rotational axis R. As such, compared to the first embodiment, the inner channel ports 114' of the second passages P2 have a greater flow cross-sectional area, helping to increase flowrate and reduce pressure losses of flow travelling therethrough. Moreover, providing elongate inner channel ports 114' increases the range of relative angular positions of the outer and inner bodies 102', 104' for which the inner channel ports 114' and outer channel ports 106' of the second passages P2 are aligned. In alternative embodiment (not shown), the inner channel port 114' of only one or more of the second passages P2 may be elongate. Additionally or alternatively, the inner channel port 114' of one or more of the first passages Pl may be elongate. The inner channel ports 114' of the second passages P2 may extend circumferentially more than 5 degrees (e.g. more than 10 degrees, or more than 20 degrees, or more than 30 degrees) about the rotational axis R. In the illustrated embodiment, each inner channel port 114' has a substantially obround profile, to inhibit turbulence in fluid passing therethrough. In some embodiments, each first and / or second passage Pl, P2 may include a plurality of inner channel ports 114' similar to the second passage P2 of the first embodiment. In the illustrated embodiment, the inner body port 108' and the outer body port 106' of each second passage P2 are larger relative to the corresponding ports of each first passage Pl. Advantageously, such a configuration helps to further reduce pressure losses in fluid moving along each of the second passages P2. In the illustrated embodiment, the inner body ports 108' of each second passage P2 are on one of the ends caps 132' at the second axial end 100b' of the inner body 104'. Each of said inner body ports 108' extends in a direction substantially parallel to the flow direction F, and thus the rotational axis R, as shown in Figure 10, which helps to reduce pressure losses in fluid passing through the second passages. In the illustrated embodiment, the inner body port 108' of each second passage P2 includes an adaptor 108b' with an approximately 90 degree swept bend enabling external fluid lines which are perpendicular to the rotational axis R to be connected to the respective inner body ports 108'. Figures 13a and 13b each show a schematic representation of the working machine 10 and hydraulic control system 20 of Figure 1, according to an exemplary embodiment. The hydraulic control system 20 includes first and second hydraulic actuators 304, 306, and a valve block 312 in the second portion 10b of the working machine 10. In the present embodiment, the first hydraulic actuator 304 is a propulsion actuator (e.g. a hydraulic motor 300 or similar) configured to drive the ground-engaging propulsion structure 14, and the second hydraulic actuator 306 is an auxiliary actuator configured to drive an auxiliary device of the working machine (e.g. a retractable stabiliser leg, or a work implement, such as the dozer blade 15). The valve block 312 may be similar to the valve block 202 of Figure 7. The pump 24 pumps hydraulic fluid from the reservoir 22 to the actuators 304, 306 via the centre joint 100, 100'. The centre joint 100, 100' includes one second passage P2, and three first passages Pla-c. The second passage Pl has a second passage portion 124, 124' having a larger flow capacity relative to the first passage portions 126, 126' of the first passages Pla-c, as described above. Hydraulic fluid is pumped from the reservoir 22 in the first portion 10a of the working machine 10 to the actuators 304, 306 in the second portion 10b via two first passages Plb,c. The first or second portions 10a,b of the working machine 10 may include a valve block to control the flow of hydraulic fluid supplied to the actuators 304, 306 for controlling the operation thereof. Hydraulic fluid is returned from the actuators 304, 306 to the reservoir 22 via the valve block 312 and the centre joint 100, 100'. In Figures 13a and 13b, hydraulic fluid returned from the propulsion actuator 304 is represented via double-line arrows, and hydraulic fluid returned from the auxiliary actuator 306 is represented via dashed arrows. The hydraulic control system 20 is configured to selectively switch between first and second modes shown in Figures 13a and 13b respectively. In the first mode shown in Figure 13a, the valve block 312 is configured such that the hydraulic fluid is returned from the propulsion actuator 304 to the reservoir 22 via the second passage P2. As such, the back pressure in the return line from the propulsion actuator 304 is reduced, helping to power the ground-engaging propulsion structure more efficiently. The first mode may be selected when the working machine 10 is travelling for extended periods of time (e.g. when it is roading). In the second mode shown in Figure 13b, the valve block 312 is configured such that the hydraulic fluid is returned from the auxiliary actuator 304 to the reservoir 22 via the second passage P2. The second mode may be selected when the working machine 10 is stationary and / or when the auxiliary actuator 306 is operated. The hydraulic control system 20 may include a controller (not shown) configured to control the valve block 312 to switch between the first and second modes. The controller may automatically switch between the two modes based on one or more received inputs. For example, the controller may automatically switch to the first mode when it determines that the working machine 10 is travelling and / or that an operator wishes the working machine 10 to travel (e.g. based on inputs from a travel speed sensor, and / or one or more operator controls (e.g. an accelerator pedal)). The controller may automatically switch to the second mode when it determines that the working machine 10 is stationary and / or that the auxiliary actuator 306 is being operated and / or that an operator wishes to operate the auxiliary actuator 306. Additionally or alternatively, the controller may switch between the first and second modes based on a manual input received from an operator (e.g. in the cab 12a). The controller may include: control circuitry; and / or processor circuitry; and / or at least one application specific integrated circuit (ASIC); and / or at least one field programmable gate array (FPGA); and / or single or multi-processor architectures; and / or sequential / parallel architectures; and / or at least one programmable logic controllers (PLCs); and / or at least one microprocessor; and / or at least one microcontroller; and / or a central processing unit (CPU), to perform the described methods. The controller may include an associated memory or the memory may be located locally to the controller or remotely. The memory may be a non-volatile flash memory. In alternative embodiments (not shown), hydraulic fluid may instead be supplied to the first and second actuators 304, 306 via the second passage P2 in the first and / or second modes respectively. Although the centre joint 100, 100' has been described in relation to the working machine 10 in Figure 1, in alternative embodiments, the centre joint 100, 100' may be used in any hydraulic system in which hydraulic fluid needs to be passed between two portions of that system that are rotatable relative to each other about a rotational axis R. For example, the centre joint may be used to transport hydraulic fluid between two portions of an actuator, such as a tiltrotator, mounted to a working arm of a working machine, where a first portion of the actuator is fixed to the arm, and a second portion of the actuator rotates relative to the working arm about a rotational axis R. Figure 14 shows a tiltrotator 400 according to an embodiment, which includes the centre joint 100, 100'. The tiltrotator 400 includes a first coupler body 412. The first coupler body 412 is pivotally connectable to a working arm (e.g. the working arm 16) so as to be pivotable about a pivot axis X. The pivot axis X is a lateral axis or horizontal axis. Put another way, the pivot axis X is a substantially transverse axis of the working machine to which the tiltrotator 400 is mounted. When the tiltrotator 400 is connected to a working machine, the pivot axis X is substantially parallel to a rotational axis between the working arm and the body of the working machine. The tiltrotator 400 includes a second coupler body 414. The second coupler body 414 is pivotally mounted to the first coupler body 412. The second coupler body 414 is pivotable relative to first coupler body 412 about a first axis Y. Pivotally mounting the second coupler body 414 to the first coupler body 412 enables the second coupler body 414 to tilt about the first axis Y. Put another way, the first axis Y is a tilt axis. The first axis Y is arranged at an angle (i.e. a non-zero angle) relative to the pivot axis X. In the illustrated arrangement, the first axis Y is substantially perpendicular to the pivot axis X. The first axis Y is a substantially fore-aft axis. The tiltrotator 400 includes a third coupler body 418. The third coupler body 418 is rotationally mounted to the second coupler body 414. The third coupler body 418 is rotatable relative to second coupling body 414 about a second axis Z. The second axis Z is arranged at an angle (i.e. a non-zero angle) relative to the first axis Y and to the pivot axis X. In the arrangement shown, the second axis Z is arranged substantially perpendicular to the first axis Y and substantially perpendicular to the pivot axis X. The second axis Z is a substantially upright axis. Put another way, the second axis Z is a vertical axis. The third coupler body 418 includes an implement mounting arrangement 422 configured to be connectable to a working implement (not shown). In the embodiment, the third coupler body 418 is a quick coupler. The mounting arrangement 422 includes first and second recesses configured to receive first and second implement pins of a working implement (not shown) therein. The centre joint 100, 100' (represented as a dashed rectangle in Figure 13) is located between the second and third coupler bodies 414. 418. One of the inner body 104, 104' and the outer body 102, 102' of the centre joint 100, 100' is substantially fixed relative to the second coupler body 414, and the other is substantially fixed relative to the third coupler body 418. As such, the rotational axis R corresponds substantially to the second axis z. The centre joint 100, 100' enables hydraulic fluid to be supplied from a working machine to an implement mounted to the third coupler body 418. The one or more embodiments are described above by way of example only and it will be appreciated that the variations are possible without departing from the scope of protection afforded by the appended claims.

Claims

1. A hydraulic centre joint comprisingan outer body;an inner body arranged at least partially within the outer body and rotatable relative to the outer body about a rotational axis;a first passage defining a fluid flow path between a first outer body port on the outer body and a first inner body port on the inner body, said first passage comprising a first passage portion in the inner body; anda second passage defining a fluid flow path between a second outer body port on the outer body and a second inner body port on the inner body, said second passage comprising a second passage portion in the inner body,wherein the first passage and the second passage are configured such that fluid can travel between the respective outer body port and inner body port for a range of relative rotational positions of the outer and inner bodies, andwherein the first passage portion is nested within the second passage portion.

2. The hydraulic centre joint of claim 1, wherein the second passage portion comprises a cavity defined by the inner body.

3. The hydraulic centre joint of claim 2, wherein the inner body comprises a cylindrical wall which is rotatably and sealably received within the outer body, the cylindrical wall having an inner surface which defines the cavity; optionally, wherein the cylindrical wall is tubular, and, optionally, has a substantially uniform thickness in a radial direction relative to the rotational axis.

4. The hydraulic centre joint of claim 3, wherein the first passage passes radially through the cylindrical wall with respect to the rotational axis.

5. The hydraulic centre joint of any one of claims 2 to 4, wherein the first passage portion comprises a pipe within the cavity; optionally, wherein the pipe comprises one or more swept bends along its length.

6. The hydraulic centre joint of any preceding claim, wherein the second passage portion has a greater flow cross-sectional area relative to the first passage portion.

7. The hydraulic centre joint of claim 6, wherein the second passage is configured to enable fluid to flow therealong in a direction counter to fluid flowing along the first passage.

8. The hydraulic centre joint of any preceding claim, wherein each passage comprises an annular channel defined between the outer body and inner body and extending at least partially around the rotational axis.

9. The hydraulic centre joint of claim 8, wherein the annular channels of respective passages are distributed along an elongate length of the centre joint and / or wherein adjacent channels are fluidly isolated from each other.

10. The hydraulic centre joint of claims 8 or 9, wherein the second passage comprises a plurality of inner channel ports in the inner body fluidly connecting the second inner body port with the respective channel, wherein the inner channel ports are adjacent said channel.

11. The hydraulic centre joint of claim 10, wherein the plurality of inner channel ports are arranged circumferentially around the rotational axis; optionally, wherein said inner channel ports are substantially equally spaced along a circumference of the inner body.

12. The hydraulic centre joint of any one of claims 8 to 11, wherein the second passage comprises an inner channel port in the inner body fluidly connecting the second inner body port with the respective channel, wherein said inner channel port is adjacent said channel, and wherein said inner channel port comprises an elongate slot having a length which extends circumferentially with respect to the rotational axis.

13. The hydraulic centre joint of any one of claims 8 to 12, wherein the first passage comprises an inner channel port in the inner body fluidly connecting the first inner body port with the respective channel, wherein said inner channel port is adjacent said channel, and wherein the first passage portion joins the first inner body port and inner channel port; optionally, wherein the first passage portion is substantially U-shaped or L-shaped.

14. The hydraulic centre joint of any one of claims 8 to 13, wherein the second passage comprises an inner channel port in the inner body fluidly connecting the second inner body port with the respective channel, wherein said inner channel port is adjacent said channel, and wherein the second passage portion joins the second inner body port and inner channel port.

15. The hydraulic centre joint of any preceding claim, comprising a plurality of first passages; optionally, wherein part of each first passage portion extends substantially parallel to the rotational axis.

16. The hydraulic centre joint of claim 15, wherein the first passage portions are arranged circumferentially around the rotational axis.

17. The hydraulic centre joint of claims 15 or 16, comprising a plurality of second passages, wherein each second passage comprises a second passage portion with a corresponding first passage portion nested therein; optionally, wherein each second passage portion has a greater flow cross-sectional area relative to each first passage portion.

18. The hydraulic centre joint of any preceding claim, comprising two or more first passages and / or two or more second passages, each passage comprising:an annular channel defined between the outer body and inner body and extending at least partially around the rotational axis;an inner channel port in the inner body fluidly connecting the respective inner body port with the respective channel; andan outer channel port in the outer body fluidly connecting the respective outer body port with the respective channel,wherein, in a predetermined rotational position of the inner and outer bodies, the corresponding inner channel port and outer channel port of two or more of the passages are substantially aligned.

19. The hydraulic centre joint of claim 18, wherein said two or more passages comprise two or more second passages.

20. The hydraulic centre joint of any preceding claim, wherein the second passage is in fluid communication with two or more second inner body ports in the inner body, and / or two or more second outer body ports in the outer body.

21. The hydraulic centre joint according to any preceding claim, wherein the inner body comprises a conduit extending substantially parallel to the rotational axis for routing a cable through the centre joint.

22. A working machine comprising:a ground engaging propulsion structure;an undercarriage supported on the ground engaging propulsion structure;a superstructure rotatably mounted to the undercarriage; and the centre joint of any preceding claim,wherein one of the inner and outer bodies is substantially fixed relative to the undercarriage and the other is substantially fixed relative to the superstructure.

23. The working machine of claims 18 or 19 and claim 22, wherein the inner channel ports are aligned with the corresponding outer channel ports when the working machine is in a travelling configuration (e.g. when a fore-aft axis of the superstructure and a fore-aft axis of the undercarriage are substantially parallel).

24. The working machine of claims 22 or 23, comprising a hydraulic system including first and second hydraulic actuators, wherein the first and second actuators are in a first machine portion of the working machine, wherein the hydraulic system is configured to supply hydraulic fluid from a second machine portion of the working machine to each actuator via one of the passages of the centre joint, and return hydraulic fluid from each actuator to the second machine portion via a different one of the passages, and wherein the hydraulic system is switchable between:a first mode, in which hydraulic fluid is supplied to, or returned from, the first hydraulic actuator via the first passage; anda second mode, in which hydraulic fluid is supplied to, or returned from, the second hydraulic actuator via said first passage.

25. A tiltrotator comprising:a first body comprising an arm mounting arrangement configured to be connectable to a working arm of a working machine;a second body pivotally mounted to the first body so as to be capable of tilting about a first axis; anda third body rotatably mounted to the second body so as to be rotatable about a second axis, where the second axis is arranged at an angle to the first axis, the third body comprising an implement mounting arrangement configured to be connectable to a working implement; andthe centre joint of any one of claims 1 to 21,wherein one of the inner and outer bodies is substantially fixed relative to the second body and the other is substantially fixed relative to the third body.27

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