An articulation with rotating hydraulic connection, in particular for mobile work machines

Abstract

 The invention relates to an articulation with rotating hydraulic connection, in particular for mobile work machines. In a very compact structure a hollow internal body (4) and an external body (1) are rotatingly coupled, with their respective cylindrical surfaces (3) and (5) placed in contact. The hydraulic rotating connection is realised by means of the coupling between the annular channels (2) envisaged in the external body (1) and the open ends (6) arranged in the hollow internal body (4). A motor (8), solidly mounted to the hollow internal body (4), activates a shaft (9), which is the drive shaft of an epicyclic reduction gear (16), (20), which latter is coaxial and reciprocally connects the hollow internal body (4) with the external body (1). A clutch (10) is interposed to operate between the shaft (9) and the hollow internal body (4).

Description

[0001] The invention relates to an articulation with rotating hydraulic connection, in particular for mobile work machines.

[0002] This kind of articulation performs the task of reciprocally connecting two parts of the machine permitting the unlimited two-way rotation of the one with regard to the other. This is the case with some types of mobile work machine such as for example articulated-arm diggers and cranes, on which a hydraulically-activated articulated arm is placed on a rotatable platform which is pivoted normally about a vertical axis. In the prior art, the articulation between the two parts is normally effected by means of a bearing of considerable diameter on one part of which a crown wheel is arranged which meshes with a sprocket on the other part which is commanded to rotate by a fixed motor reducer, evidently eccentrically disposed with respect to the rotation axis. The rotating joint, completely separated from the bearing, but coaxially situated with respect to it, ensures the hydraulic connection between the components of the hydraulic circuit situated on the two part of the machine.

[0003] In the prior art the above-described structure is the cause of many drawbacks, among which is the difficulty of correctly assembling and correctly reciprocally adjusting the various parts: bearing, motor reducer with sprocket, rotating connection. Assembly time and costs are notable.

[0004] The other negative characteristic relates to the mass and weight of the solutions embraced in the prior art.

[0005] The present invention, as described in the claims which follow, seeks to obviate the drawbacks and shortcomings in the prior art, with an articulation with rotating hydraulic connection which groups together in a single compact device all the articulation components.

[0006] Further characteristics and advantages will better emerge in the detailed description that follows, of a preferred but non-exclusive embodiment of the invention, here illustrated purely in the form of a non-limiting example in the attached diagrams, wherein:

― Figure 1 shows a schematic longitudinal section along an axial plane;

― Figure 2 shows, schematically, the embodiment in Figure 1;

― Figure 3 shows, schematically, a second embodiment.

[0007] With reference to the illustrations, fig 1 shows the external body of an articulation with rotating hydraulic connection able to be solidly mounted on one of the two parts reciprocally connected by the articulation; for example, in the case of a mobile work machine, to the wheel-mounted frame. For this purpose the external body 1 is equipped on its upper part with a flange 23 having through bores 24 for connection by means of bolts. The external body 1 has beneath the flange 23 an internal cylindrical surface 3 having annular channels 2 in communication with an external conduit 30. A holow internal body 4 is coaxially and rotatingly coupled to the external body 1 and has an external cylindrical surface 5 shaped and arranged to be in face-on contact with the internal cylindrical surface 3. The open ends 6 of hydraulic conduits 7 envisaged solidly in the hollow internal body 4 are arranged in correspondence with the external cylindrical surface 5. Each hydraulic conduit 7 has an open end 6 located in such a way that it faces one of the annular channels 2 bored into the external body 1. The rotating seal between the annular channels 2 and the open ends 6 is circumferentially guaranteed by seals 25. The hollow internal body 4 is supported to the external body 1 by means of bearings 26 and 27. A hydraulic motor 8 is fixed to the hollow internal body 4, which is axialsymmetric in form and has in its upper part a flange 28 for its connection with the upper part of the machine. The hydraulic motor 8, housed in the internal cavity of the hollow internal body 4, activates a shaft 9 which is arranged coaxially with the cylindrical surfaces 3 and 5 and is engaged to the hollow internal body 4 by means of a hydraulically activated clutch 10. The clutch 10 is of the disk-type and is kept in the engaged position by a system of coaxial springs 11 which act upon a disk collar 12 with antagonistic action with respect to that of the pressurised fluid introduced into the annular channel 13 of a jack, whose annular piston 14 is coaxially slidable and sealed inside a cylindrical chamber 15 bored coaxially in the hollow internal body 4. The shaft 9 is the drive-shaft of an epicyclic reduction gear, indicated by 16, which reciprocally connects the hollow internal body 4 with the external body 1. In particular, the epicyclic reduction gear 16 comprises a satellite carrier 17 which is solid to the hollow internal body 4 and an internally cogged crown wheel 18, to which the satellites 19 mesh, solid to the external body 1 and arranged coaxially to the rotation axis of the shaft 9. The clutch 10 is kept in the engaged position by the action of the springs 11. Disengagement is performed by sending pressurised fluid into the chamber 13 whenever the rotation command is activated to produce rotation in either direction of the hollow internal body 4 with respect to the external body 1. In this situation the shaft 9 is free to rotate with respect to the hollow internal body 4 and thus to produce the rotation of the latter with respect to the external body 1 according to the reduction rapport of the epicyclic reduction gear 16.

[0008] The group is extremely compact, without substantial limits to transmission power and to the number of rotating hydraulic connections between the two mobile parts of the articulation.

[0009] In the second embodiment illustrated in fig 3, instead of the epicyclic reduction gear 16, which can be in one of more stages, a more normal reduction gear 20 is arranged, in which the chassis 21 is solid to the hollow internal body 4 while the conduit shaft 22 is mounted to the external body 1 and coaligned with the drive shaft 9. Both illustrated embodiments are characterised by extreme compactness and permit of great ease and rationality of assembly and dissembly.

Claims

1. An articulation with rotating hydraulic connection, in particular for mobile work machines, comprising:

― an external body 1 having in correspondence with its own cylindrical surface 3, annular channels 2 of said connection;

― a hollow internal body 4 coaxially and rotatingly supported and coupled to said external body 1 and having an external cylindrical surface 5 at which surface 5 the open ends 6 of various hydraulic conduits 7 are located, which hydraulic conduits 7 face on to said annular channels 2; said hollow internal body 4 having a hydraulic motor 8 fixed to it for the generation of rotation movement with respect to said external body 1;

― motor transmission, comprising; a drive shaft 9, activated directly by said hydraulic motor 8, arranged coaxially to the cylindrical surfaces 3 and 5; a reduction gear 16 with coaxial gears (with engagement and disengagement of rotation on the same axis) which reciprocally connects the external body 1 with the hollow internal body 4 and has said shaft 9 as drive shaft.

2. Articulation as in claim 1, wherein said drive shaft 9 is engageable to said hollow internal body 4 by means of a clutch 10 which is hydraulically disengageable.

3. Articulation as in claim 1, wherein said hydraulic motor 8 is housed in the internal cavity of said hollow internal body 4.

4. Articulation as in claim 1, wherein said clutch 10 is of the disk-type and is kept in the engaged position by a system of coaxial springs 11 which act upon a disk collar 12 with antagonistic action with respect to that of pressurised fluid introduced into the annular channel 13 of a hydraulic jack, whose annular piston 14, coaxially slidable and sealed inside a cylindrical chamber 15 bored coaxially in the hollow internal body 4, is solid to the disk collar 12.

5. Articulation as in claim 4, wherein said reduction gear is an epicyclic reduction gear 16 in which the drive shaft 9 is solid to the motor shaft 29, the satellite carrier 17 is solid to the hollow internal body 4 and the internally cogged crown wheel 18, with which the satellites 19 mesh, is solid to the external body 1.

6. Articulation as in claim 4, wherein said reduction gear is a reduction gear 20 with at least two stages in which the chassis 21 is solid to the hollow internal body 4 and the conduit shaft 22 is fixed to the external body 1 coaxially to the drive shaft 9.

Drawing