Rotary joint

Abstract

The invention is a rotary joint for conveying a fluid between two fluid conveying components, comprising : i ) a hollow shaft; ii ) a first j unction; iii ) a second j unction; the joint being characterized in that : - between the first j unction and an outer lateral surface of the first end portion, a first annular chamber in fluid communication with the main passage is obtained; between the second j unction and an outer lateral surface of the second end portion, a second annular chamber in fluid communication with the main passage is obtained; wherein each of said first annular chamber and second annular chamber respectively forms a first and a second thrust surface on which the fluid present in said first annular chamber and second annular chamber acts.

Description

ROTARY JOINTDESCRIPTIONField of application

[0001] The present invention concerns a rotary joint for the connection between two fluid conveying components .

[0002] In the field of mechanics and hydraulics, it is known to provide various rotary joints that allow the connection of two fluid conveying components, of the same or different types .

[0003] A typical issue with the rotary joints known in the prior art is the difficult management of the tensions and stresses that are generated between the two fluid conveying components due to the flow of the fluid itself .

[0004] In fact, the tensions and stresses that are generated between the two fluid conveying components lead to difficult control of the components themselves, which tend to move and twist upon themselves .

[0005] Such movements of the fluid conveying components are undesirable, as they may lead to breakages, with consequent fluid leakage and malfunctions .Solution of the invention

[0006] There is therefore a strong need to provide a rotary joint for the connection of two fluid conveying components capable of overcoming the typical drawbacks of the prior art .

[0007] A main obj ect of the present invention is therefore to propose a rotary joint capable of meeting such a need.

[0008] In particular, an obj ect of the present invention is to provide a rotary joint in which the tensions generated by the axial rotation of the two fluid conveying components, which are a source of problems for the effective transport of fluid inside the components themselves, are significantly reduced, if not completely eliminated .

[0009] In particular, said tensions cause entanglements and / or breakages of the fluid conveying components .

[0010] These obj ects are achieved by a rotary joint in accordance with claim 1. The claims depending therefrom describe preferred or advantageous embodiments of the invention .Description of drawings

[0011] The features and advantages of the rotary joint will in any case become evident from the following description of some preferred embodiments, given by way of example and not limitation, with reference to the accompanying figures, in which:- Figure 1 shows a side view of the rotary joint obj ect of the present invention;- Figure 2 shows an axial section of the rotary joint obj ect of the present invention;Figure 3 shows an exploded axonometric view of the rotary joint obj ect of the present invention;- Figure 4 shows an axonometric view of a component of the joint obj ect of the present invention;- Figure 5 shows a detail of the section shown in figure 2 .Detailed description

[0012] With reference to the aforementioned figures, the rotary joint obj ect of the present invention is generally denoted by the reference number 1.

[0013] The rotary joint 1 comprises a hollow shaft 3, which extends along an axis X-X between a first end 30' and a second end 30" .

[0014] Preferably, the hollow shaft 3 has a substantially cylindrical shape .

[0015] The rotary joint 1 comprises a first junction 2, connectable to a fluid conveying component, fluidically connected with the shaft 3 at the first end 30' .

[0016] Preferably, the first junction 2 has a substantially cylindrical shape, coaxial with the hollow shaft 3 along the axis X-X .

[0017] For example, the fluid conveying component connected to the first junction 2 is a pipe .

[0018] The rotary joint 1 comprises a second junction 4, connectable to a fluid conveying component, fluidicallyconnected with the hollow shaft 3 at the second end 30" .

[0019] Preferably, the second junction 4 has a substantially cylindrical shape, coaxial with the hollow shaft 3 along the axis X-X .

[0020] Alternatively, the second junction 4 has a more complex shape, for example an "angled" or "L-shaped" form.

[0021] For example, the fluid conveying component connected to the second junction 4 is a pipe .

[0022] Consequently, the main passage of the fluid in the rotary joint 1 is composed of the internal volume defined by the first junction 2, the hollow shaft 3 and the second junction 4, which extend coaxially along the axis X-X .

[0023] In accordance with the present invention, between the first junction 2 and an outer lateral surface of the first end portion 30' a first annular chamber 5' in fluid communication with the main passage is obtained.

[0024] Furthermore, also in accordance with the invention, between the second junction 4 and an outer lateral surface of the second end portion 30" a second annular chamber 5" in fluid communication with the main passage is obtained.

[0025] In accordance with the invention, in each of said first annular chamber 5' and second annular chamber 5" arespective first and second thrust surface are obtained, on which the fluid present in said first annular chamber 5' and second annular chamber 5" acts .

[0026] In accordance with the invention, said first and second thrust surfaces have the same area .

[0027] The thrusts generated by the action of the fluid are therefore equal and opposite, generating a condition of dynamic equilibrium between the first junction 2 and the hollow shaft 3 and between the second junction 4 and the hollow shaft 3.

[0028] This condition of dynamic equilibrium is favourable for the management of the stresses and tensions generated by the movement of the fluid.

[0029] This condition is even more favourable when the fluid conveyed is oil .

[0030] In fact, this condition of dynamic equilibrium results in a reduction of friction, vibrations and noise, stress on the components, alignment difficulties between the components, and movement limitations .

[0031] The condition of dynamic equilibrium also allows for compensation of possible issues related to the mechanical tolerances of the components .

[0032] In particular, the equal and opposite thrusts generated by the fluid allow for improved rotation of the first junction 2 on the hollow shaft 3.

[0033] In a preferred embodiment, each of the first and second thrust surfaces is constituted by the surface, respectively, of a first annular sealing gasket 52' , housed in the first annular chamber 5' , and of a second annular sealing gasket 52", housed in the second annular chamber 5" .

[0034] In a preferred embodiment, each of said first 52' and second annular sealing gasket 52" creates a seal between the outer lateral surface of the respective end of the hollow shaft and the respective junction .

[0035] The first 52' and the second annular sealing gasket 52" prevent the fluid from exiting the rotary joint 1, thus avoiding leaks and / or spillages .

[0036] In a preferred embodiment, said outer lateral surfaces of the first 30' and second end portion 30" of the hollow shaft 3 have the same diameter .

[0037] Furthermore, in a preferred embodiment, the first 52' and the second 52" annular sealing gasket are identical to each other .

[0038] In particular, in a preferred embodiment, the first 52' and the second annular sealing gasket 52" are of the 0-ring type .

[0039] Preferably, the first 52' and the second annular sealing gasket 52" are made of a polymeric material, for example NBR or FKM.

[0040] In a preferred embodiment, each of the annular sealing gaskets 52' , 52" rests, on the side opposite the fluid thrust direction, on a respective guide washer 53' , 53" .

[0041] In particular, the respective guide washers 53' , 53" are intended to provide a homogeneous reaction to the thrusts generated by the action of the fluid applied to the annular sealing gaskets 52' , 52" .

[0042] In particular, the respective guide washers 53' , 53" are made of a thermoplastic material .

[0043] According to a preferred embodiment, each of said first 5' and second annular chamber 5" is formed by a groove obtained in an inner lateral surface of the respective first 2 and second junction 4.

[0044] In a preferred embodiment, the second junction 4 is engaged to the hollow shaft 3 by means of a threaded coupling .

[0045] In particular, the second junction 4 is screwed onto the respective end portion 30" of the hollow shaft 3.

[0046] In a preferred embodiment, the portion of the second junction 4 fitted onto the respective end portion 30" of the hollow shaft 3 has a threaded portion 33 on its inner surface for screwing to the hollow shaft 3.

[0047] In a preferred embodiment, the second chamber 5" is positioned axially between said threaded portion 33 andthe respective end of the hollow shaft 3.

[0048] In a preferred embodiment, each of said first junction 2 and second junction 4 forms, on its inner wall, an annular abutment shoulder 21, 41 against which a respective annular abutment surface 34' , 34" formed by a respective end of the hollow shaft 3 abuts .

[0049] Furthermore, in a preferred embodiment, in each annular abutment surface 34' , 34" and / or in each annular abutment shoulder 21, 41, a fluid collection passage is obtained, suitable for allowing a flow of fluid from the main passage to the respective first 5' and second annular chamber 5" passing between each end of the hollow shaft 3 and the respective annular abutment shoulder 21, 41 .

[0050] In a preferred embodiment, said collection passage is formed by a spiral groove 32' , 32" .

[0051] In particular, the spiral shape of such groove 32' , 32" is advantageous for conveying an adequate amount of fluid to the respective first 5' and second annular chamber 5" without compromising the operation of the joint .

[0052] In particular, "adequate" means a quantity of fluid sufficient to facilitate the rotation of the first 2 and second junction 4 with respect to the hollow shaft 3.

[0053] Consequently, the amount of fluid that passesthrough the spiral groove 32' , 32" is not excessive and does not lead to fluid leakage and / or spillage .

[0054] In a preferred embodiment, the hollow shaft 3 forms, on its outer surface, a collar 31.

[0055] In particular, the collar 31 is suitable for creating an axial constraint between the shaft 3 and the first junction 2.

[0056] Said collar 31 is preferably made in one piece with the hollow shaft 3, and extends over its entire outer surface .

[0057] The collar 31 is axially delimited by a first radial collar surface 311 and a second radial collar surface 312, for example parallel to the first .

[0058] Preferably, the collar 31 has a rectangular annular section .

[0059] In a preferred embodiment, an annular groove 22 is obtained in the inner surface of the first junction 2, engaged by said collar 31.

[0060] In particular, the annular groove 22 serves to create an axial constraint between the first junction 2 and the hollow shaft 3.

[0061] In a preferred embodiment, the first junction 2 is formed by the axial coupling of a first component 201 and a second component 202.

[0062] The configuration of the first junction 2 in twocomponents allows, in particular, the formation of the annular groove 22 which, being engaged by the collar 31, would make assembly of the first junction 2 on the hollow shaft 3 more difficult if the first junction were made in a single piece .

[0063] Therefore, the first component 201 and the second component 202 jointly form the annular groove 22.

[0064] In one embodiment, the first component 201 and the second component 202 are screwed to each other .

[0065] For example, the first component 201 has a threaded distal portion 201' which is screwed onto an externally threaded cylindrical portion 202' of the second component 202 .

[0066] More specifically, in one embodiment, the threaded distal portion 201' of the first component extends axially from an intermediate portion 201" which forms a first axial portion, for example approximately half, of the annular groove 22.

[0067] The cylindrical portion 202' of the second component 202 internally forms a step 202" which constitutes a second axial portion of the annular groove 22.

[0068] During assembly, the second component 202 is fitted onto the hollow shaft 3 from the side of the second end 30" of the hollow shaft 3 (before the second junction 4 is fitted onto the hollow shaft 3 from the same secondend 30") ; the first component 201 is instead fitted onto the hollow shaft 3 from the side of the first end 30' .

[0069] In one embodiment, the second component 202 further forms a locking ring 202a suitable for being engaged by a tool for screwing between the first component 201 and the second component 202.

[0070] The first component 201 and the second component 202 thus allow for effective assembly of the first junction 2, maintaining a solid structure and preventing fluid leakage .

[0071] In a preferred embodiment, the rotary joint 1 comprises a skid group 6, interposed between the first junction 2 and the hollow shaft 3 to promote rotation of the first junction 2 on the hollow shaft 3.

[0072] In a preferred embodiment, the skid group 6 comprises a first skid 63, suitable for facilitating the sliding of the hollow shaft 3 into the first junction 2.

[0073] Preferably, the main skid 63 has an annular shape .

[0074] Preferably, the main skid 63 is made of a thermoplastic material .

[0075] Preferably, the main skid 63 is made of a low-friction material .

[0076] In a preferred embodiment, the skid group 6 also comprises a pair of second skids 61, 62.

[0077] In particular, the pair of second skids 61, 62 issuitable for partially unloading the thrust of the first j unction 2 .

[0078] In particular, the pair of second skids 61, 62 has an anti-seize function in the relative rotation between the first junction 2 and the hollow shaft 3.

[0079] Preferably, the pair of second skids 61, 62 is housed in the annular groove 22 in respective skid seats 611, 621 axially separated from each other by the collar 31 .

[0080] In particular, the pair of second skids 61, 62 has an annular shape .

[0081] In one embodiment, the rotary joint 1 comprises an 0-ring 8, engaged to the hollow shaft 3, positioned inside a chamber 81 obtained between the hollow shaft 3 and the inner lateral surface of the second component 202 .

[0082] In particular, said 0-ring 8 serves to further fluidically isolate the rotary joint 1.

[0083] Preferably, the 0-ring 8 is made of NBR or FKM material .

[0084] Innovatively, the rotary joint obj ect of the present invention overcomes the drawbacks of the joints typical of the known art .

[0085] Advantageously, the rotary joint allows the two fluid conveying components to rotate and move withoutgenerating tensions or stresses .

[0086] Advantageously, the presence of the first and second annular chambers makes it possible to exploit the thrust effect generated by the fluid to allow better mobility of the joint components .

[0087] Advantageously, the presence of the first and second annular chambers allows the exploitation of the presence of the fluid to permit relative rotation of the first junction 2 and the hollow shaft .

[0088] Advantageously, the first and second annular sealing gaskets allow fluidic isolation of the joint and in particular of the first and second annular chambers, while enabling a homogeneous distribution of the fluid thrust .

[0089] Advantageously, the equal diameters of the outer lateral surfaces of the first and second end portions of the hollow shaft allow the generation of equal and opposite thrusts at the two ends of the hollow shaft .

[0090] Advantageously, the threaded coupling between the hollow shaft and the second junction ensures a solid structure of the rotary joint .

[0091] Advantageously, the second annular chamber is spaced from the threaded portion, preventing the threaded portion from affecting the thrust generated by the fluid in the second annular chamber .

[0092] Advantageously, the annular abutment shoulders ensure precise engagement between the first junction and the hollow shaft and between the second junction and the hollow shaft .

[0093] Advantageously, the fluid collection passage ensures a constant and non-excessive supply of fluid to the first and second annular chambers .

[0094] Advantageously, the spiral groove enables management of the fluid supply to the first and second annular chambers without altering the operation of the joint .

[0095] Advantageously, the collar allows for a male-female type engagement between the hollow shaft and the first junction, ensuring a secure coupling.

[0096] Advantageously, the skid group facilitates the relative rotation of the joint elements, preventing the generation of stresses and wear of the components .

[0097] It is clear that, to the embodiments of the rotary joint, a person skilled in the art, in order to meet specific needs, may introduce modifications or replace elements with other functionally equivalent ones .

[0098] Such modifications are also within the scope of protection as defined by the following claims . Moreover, each variant described as belonging to a possible embodiment may be implemented independently of the other described variants .List of reference numbers :1 Rotary joint;2 First junction;201 First component;201' Threaded distal portion;201" Intermediate portion;202 Second component;202' Cylindrical portion;202" Step;202a Locking ring;22 Annular groove;4 Second junction;3 Hollow shaft;30' First end portion of the hollow shaft; 30" Second end portion of the hollow shaft; 31 Collar;311 First end of the collar;312 Second end of the collar;32' First spiral groove;32" Second spiral groove;33 Threaded portion;34' First annular abutment surface;34" Second annular abutment surface;5' First annular chamber;5" Second annular chamber;52' First annular sealing gasket;52" Second annular sealing gasket;53' First guide washer;53" Second guide washer;21 First annular abutment shoulder; 41 Second annular abutment shoulder; 6 Skid group;61 First skid;62 Second skid;611, 621 Skid seats;63 Main skid;81 Chamber;8 0-ring.

Claims

CLAIMS1. A rotary joint ( 1 ) for the connection between two fluid conveying components, comprising:(i) a hollow shaft (3) , extending along a shaft axis (X-X) between a first end portion (30' ) and a second end portion (30") so as to identify a main passage for the fluid;ii) a first junction (2 ) , connectable to a first fluid conveying component of the two fluid conveying components, the first junction (2 ) being sealingly fitted onto the first end portion (30' ) of the hollow shaft with possibility of rotation about the shaft axis (X-X) ; iii) a second junction (4 ) , connectable to the second fluid conveying component of said two fluid conveying components, the second junction (4 ) being sealingly fitted onto the second end portion (30") of the hollow shaft ( 3 ) ;the joint being characterized in that :between the first junction (2 ) and an outer side surface of the first end portion ( 30 ’ ) , a first annular chamber (5' ) in fluid communication with the main passage is obtained;between the second junction (4 ) and an outer side surface of the second end portion (30") , a second annular chamber (5") in fluid communication with the main passageis obtained;wherein each of said first annular chamber ( 5' ) and second annular chamber (5") forms a first and a second thrust surface, respectively, on which the fluid present in said first annular chamber ( 5' ) and second annular chamber (5") acts, and wherein said first and second thrust surfaces have the same area .

2. Rotary joint ( 1 ) according to claim 1, wherein each of said first thrust surface and second thrust surface consists of the surface of a first annular sealing gasket (52' ) housed in the first annular chamber (5' ) and a second annular sealing gasket (52") housed in the second annular chamber (5") , respectively, each of said first (52' ) and second (52") annular sealing gaskets creating a seal between the outer side surface of the respective end of the hollow shaft and the respective junction .

3. Rotary joint ( 1 ) according to claim 2, wherein said outer side surfaces of the first (30' ) and second (30") end portions of the hollow shaft (3) have the same diameter, and wherein the first (52' ) and second (52") annular sealing gaskets are equal to each other .

4. Rotary joint ( 1 ) according to claim 2 or 3, wherein the first (52' ) and second (52") annular sealing gaskets are O-rings .

5. Rotary joint ( 1 ) according to any one of claims 2-4,wherein each of the annular sealing gaskets (52' , 52") rests, on the opposite side with respect to the fluid thrust direction, on a respective guide washer (53' , 53") .

6. Rotary joint ( 1 ) according to any one of the preceding claims, wherein each of said first (5' ) and second (5") annular chambers is formed by a groove obtained in an inner side surface of the respective first (2 ) and second (4 ) junctions .

7. Rotary joint ( 1 ) according to any one of the preceding claims, wherein the second junction (4 ) is screwed onto the respective end portion (30") of the hollow shaft (3) .

8. Rotary joint ( 1 ) according to claim 7, wherein the portion of the second junction (4 ) fitted onto the respective end portion (30") of the hollow shaft (3) has a threaded portion (33) on the inner surface thereof to be screwed to the hollow shaft ( 3) , wherein the second chamber (5") is positioned axially between said threaded portion (33) and the respective end of the hollow shaft (3) .

9. Rotary joint ( 1 ) according to any one of the preceding claims, wherein each of said first junction (2 ) and second junction (4 ) forms, on the inner wall thereof, an annular abutment shoulder (21 , 41 ) against which a respective annular abutment surface (34' , 34") formed bya respective end of the hollow shaft ( 3 ) abuts , and wherein in each annular abutment surface ( 34 ' , 34" ) and / or in each annular abutment shoulder ( 21 , 41 ) , a fluid collection passage is obtained, suitable for allowing an inflow of fluid from the main passage to the respective first ( 5 ' ) and second ( 5" ) annular chambers passing between each end of the hollow shaft ( 3 ) and the respective annular abutment shoulder ( 21 , 41 ) .10 . Rotary j oint ( 1 ) according to claim 9 , wherein said collection passage is formed by a spiral groove ( 32 ' , 32" ) .11 . Rotary j oint ( 1 ) according to any one of the preceding claims , wherein the hollow shaft ( 3 ) forms , on the outer surface thereof , a collar ( 31 ) , and wherein in the inner surface of the first j unction ( 2 ) , there is obtained an annular groove ( 22 ) engaged by said collar ( 31 ) to create an axial constraint between the first j unction ( 2 ) and the hollow shaft ( 3 ) .12 . Rotary j oint ( 1 ) according to claim 11 , wherein the first j unction ( 2 ) is formed by axially coupling a first component ( 201 ) and a second component ( 202 ) , the first component ( 201 ) and the second component ( 202 ) j ointly creating the annular groove ( 22 ) .

13. Rotary j oint ( 1 ) according to claim 12 , wherein the first component ( 201 ) and the second component ( 202 ) arescrewed together .14 . Rotary j oint ( 1 ) according to any one of the preceding claims , comprising a skid group ( 6 ) interposed between the first j unction ( 2 ) and the hollow shaft ( 3 ) to promote a rotation of the first j unction ( 2 ) about the hollow shaft ( 3 ) .15 . Rotary j oint ( 1 ) according to claims 11 and 14 , wherein the skid group ( 6 ) comprises a first skid ( 63 ) , suitable for faci litating the sliding of the hollow shaft ( 3 ) into the first j unction ( 2 ) , and a pair of second skids ( 61 , 62 ) , having an anti-sei ze function, suitable for partially unloading the thrust of the first j unction ( 2 ) , housed in the annular groove ( 22 ) in respective skid seats ( 611 , 621 ) axially separated from each other by the collar ( 31 ) .

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