WO2014148982A1

WO2014148982A1 - Coupling device comprising a banjo union

Info

Publication number: WO2014148982A1
Application number: PCT/SE2014/050298
Authority: WO
Inventors: Christoffer LIND
Original assignee: Scania CV AB
Current assignee: Scania CV AB
Priority date: 2013-03-19
Filing date: 2014-03-12
Publication date: 2014-09-25
Anticipated expiration: 2015-09-19
Also published as: SE1350337A1; DE112014001063T5

Abstract

The invention pertains to a coupling device (101) comprising a banjo nipple (102), a pipe (104) and at least one sealing element (106), which is designed to abut against the banjo nipple (102) and the pipe (104), where the banjo nipple (102) has a substantially axial section (108) with a central line (115), the pipe (104) has a central axis (114) and an end section (110), the end section (110) of which is connected to a part of the substantially axial section (108) of the banjo nipple (102). The banjo nipple (102) and the pipe (104) are movably connected to each other, so that the banjo nipple's (102) central line (115) and the pipe's (104) central axis (114) may be angularly displaced in relation to each other with an angular displacement (a). The coupling device constitutes a flexible coupling device which eliminates the impact of tensions and strains that might compromise its function.

Description

Coupling device comprising a banjo union

BACKGROUND OF THE INVENTION AND PRIOR ART The present invention relates to a coupling device according to the preamble of patent claim 1 . Coupling devices comprising a banjo nipple and a pipe are used to lead a fluid to or from an apparatus, such as a machine. For example, coupling devices with a banjo nipple are used to lead fuel from a fuel pipe into a combustion engine.

The banjo nipple is connected to the apparatus with a screw, which is designed with a channel extending along the shaft of the screw and culminating at the end turned from the head of the screw. The channel also extends radially in relation to the screw's longitudinal shaft through one or several diamet- rical drillings in the screw's shaft. The channel in the screw may also be designed in a different manner.

Thus the fluid flows through the pipe, into the banjo nipple, further along through the screw's channel in order finally to be led into the channel of the apparatus. The fluid may also flow in the opposite direction.

The banjo nipple is usually connected with the pipe through a welding process, so that the banjo nipple becomes fixedly connected and thus fixed to the pipe. The heat treatment of the banjo nipple and the pipe arising in connection with the welding process entails that cracks may arise inside or near the welding joint, which may lead to fractures and leakage of fluid. In particular if the banjo nipple must be forced into a specific position in order to be connected to the apparatus, tensions in the pipe, the joint and the nipple arise; tensions that contribute to an increased risk of cracking and fractures. If the coupling device is used to lead fuel to a combustion engine, vibrations also arise, which also contribute to an increased risk of cracking in and fracture of the pipe, the joint and the nipple. If the banjo nipple must be forced into a certain position during assembly, difficulties in fitting the screw in the banjo nipple and in the apparatus may arise. These fitting difficulties may lead to the threads on the screw and/or in the apparatus being destroyed, which in turn may lead to metal chips from the threads being led along through the combustion engine's fuel system and cause damage.

There are coupling devices which comprise a banjo nipple, where a section of the pipe has been replaced by a flexible hose. Thus the banjo nipple is allowed to be connected with the apparatus without considerable tensions arising in- side the pipe, the welding joint or the banjo nipple. The flexible hose entails disadvantages, however, such as increased costs and a risk of leaks in the connection between the hose and the pipe. Further disadvantages with the flexible hose are that it requires space and that it may need to be protected against wear and tear.

Document GB 903284 - A shows a coupling device which comprises a banjo nipple, where a section of the pipe has been replaced by a flexible hose.

There are also coupling devices comprising a banjo nipple which may be turned and shifted in relation to each other through the use of a lathed sleeve, which is welded onto the pipe and envelops a section of the banjo nipple. Thus the banjo nipple is permitted to be connected with the apparatus without considerable tensions arising in the pipe or the banjo nipple. The lathed sleeve, however, entails the supply of an additional component and therefore an in- creased manufacturing cost. The welding joint between the pipe and the pipe sleeve also entails an increased risk of cracking and constitutes a potential leakage site.

Document SE 524308 - C2 shows a coupling device comprising a banjo nipple and a pipe sleeve insertable into the end of the pipe. Document SE 535893 - C shows a coupling device comprising a banjo nipple where the pipe and the banjo nipple are permitted to be shifted and turned in relation to each other without a sleeve. The end section of the pipe has a broader inner diameter than the inner diameter in the pipe's remaining exten- sion and envelops a section of the banjo nipple. A first and a second sealing element are arranged between the pipe and the banjo nipple. The first sealing element prevents dirt from the environment impacting the second sealing element; a second sealing element that prevents fluid from leaking out from the connection between the pipe and the banjo nipple. In this manner, a coupling device is achieved which reduces the risk of leakages of fluid.

Despite prior art solutions in this area, there is a need to develop a coupling device which is more flexible than prior art technology while it also prevents leakages of fluid.

SUMMARY OF THE INVENTION

The objective of the present invention is to achieve a flexible coupling device, which is easy to mount.

The objective of the present invention is to achieve a flexible coupling device, which eliminates tensions and strain.

Another objective of the invention is to prevent leakages of fluid from a cou- pling device.

Another objective of the invention is to achieve a coupling device, which entails reduced manufacturing costs. These objectives are achieved with the coupling device of the type specified at the beginning, and which is characterised by the features specified in the characterising portion of patent claim 1 . By movably connecting the banjo nipple and the pipe to each other, so that the banjo nipple's centre line and the pipe's central axis may be angularly displaced in relation to each other, a flexible coupling device is achieved which is articulated. The angular displacement entails a simpler mounting and as the coupling device comprises few components, the manufacturing cost is reduced. With the at least one sealing element arranged in connection with the banjo nipple and the pipe, a coupling device which prevents leakages of fluid is also achieved. The possibility of angular displacement entails also that ten- sions and strains between the banjo nipple and the pipe are eliminated.

Suitably, the angle displacement may be between 1 -10 degrees, preferably 3-5 degrees. By arranging the angular displacement so that it may only be angularly displaced a few degrees, a sufficient movement is allowed to absorb the tensions which normally occur, while simple sealing elements may be used.

Suitably, an additional sealing element is arranged in connection with the banjo nipple and the pipe. The inner sealing element's task is to seal against the fluid in the pipe and prevent leakage, while the outer sealing element's task is to prevent dirt from the environment from impacting the inner sealing element. The two sealing elements suitably have different material properties with different temperature sensitivities in order to provide a good sealing function. Alternatively, a third sealing element may be arranged in connection with the banjo nipple and the pipe. The sealing elements suitably consist of O-rings. Suitably, the substantially axial section in the banjo nipple has tracks for fixing of sealing elements.

Preferably, the banjo nipple and the pipe are connected so that the end section of the pipe envelops a part of the banjo nipple's essentially axial section. The angular displacement is then suitably achieved by designing the banjo nipple's substantially axial section as a barrel. The spherical surfaces in the substantially axial section's exterior may then abut and turn toward the inside of the pipe's end section, which entails that the banjo nipple's centre line and the pipe's central axis may be angularly displaced in relation to each other.

Alternatively, the end section of the pipe is clamped and has a waistline. The inner diameter of the end section thus decreases from one end of the end section and in towards the middle of the end section, following which the inner diameter again increases toward the other end of the end section. The inside of the pipe's end section thus has spherical surfaces, against which the substantially axial section of the banjo nipple may abut and turn. In this manner, an angular displacement is achieved between the banjo nipple's central line and the pipe's central axis.

Preferably, the pipe's end section has a larger inner diameter compared with the inner diameter of the remainder of the pipe's extension. Furthermore, the end section of the pipe suitably has a flange directed toward the pipe's central axis, which engages in an outer track formed in the banjo nipple's substantially axial section. The flange's task is to ensure that the banjo nipple and the pipe remain connected when the coupling device is not mounted. Alternatively, the pipe has the same inner diameter across its entire extension.

Alternatively, the banjo nipple and the pipe are connected so that the banjo nipple's substantially axial section envelops the pipe's end section. Suitably, the banjo nipple's substantially axial section is then designed so that its inner diameter decreases from one end of the substantially axial section in towards the middle, following which the inner diameter then increases from the middle and out towards the other end of the substantially axial section. The inside of the substantially axial section thus has spherical surfaces, against which the outside of the pipe's end section may abut and turn. In this manner, an angular displacement is achieved between the banjo nipple's central line and the pipe's central axis. Alternatively, the pipe's end section is designed as a barrel. The spherical surfaces on the outside of the pipe's end section may in this manner abut and turn against the inside of the banjo nipple's substantially axial section. In this manner, an angle displacement is achieved between the banjo nipple's central line and the pipe's central axis.

Preferably, the banjo nipple and the pipe may also be axially displaced and turned in relation to each other. In this manner, a coupling device is achieved which is flexible in all directions and thus easy to fit.

Where the pipe's end section envelops the banjo nipple's substantially axial section, the axial displacement is suitably limited by, on the one hand, a transition between the larger and the smaller inner diameter of the pipe and, on the other hand, the outer track's axial extension in the banjo nipple's substantially axial section.

Other advantages of the invention are set out in the detailed description below.

BRIEF DESCRIPTION OF DRAWINGS

Below is a description of, as examples, preferred embodiments of the invention with reference to the enclosed drawings, in which: shows a coupling device in a cross-sectional view according to a first embodiment,

shows the coupling device in Fig. 1 in an angularly displaced position,

shows the coupling device according to the first embodiment in a cross-sectional view along the line I - 1 in Fig. 1 ,

shows a coupling device in a cross-sectional view according to a second embodiment, Fig. 4 shows a coupling device in a cross-sectional view according to a third embodiment, and

Fig. 5 shows a coupling device in a cross-sectional view according to a fourth embodiment.

DETAILED DESCRIPTION OF THE INVENTION

Fig. 1 a and 1 b show a coupling device 101 in a cross-sectional view according to a first embodiment. The coupling device 101 comprises a banjo nipple 102, a pipe 104 and two sealing elements 106, which are designed to abut against the banjo nipple 102 and the pipe 104. The sealing elements 106 preferably have different material properties in order to provide a good sealing function. The sealing elements 106 are suitably arranged at a distance from each other and envelop a part of a substantially axial section 108 of the banjo nipple 102. The task of one of the sealing elements 106 is to seal against the fluid in the pipe and prevent leakage, while the task of the second sealing element 106 is to seal against dirt from the environment. For example, the sealing elements 106 may consist of O-rings. One end section 1 10 of the pipe 104 envelops the sealing elements 106 and at least one part of the substantially axial section 108 of the banjo nipple 102. The end section 1 10 of the pipe 104 has a larger inner diameter compared with the inner diameter of the remainder of the extension of the pipe 104. The substantially axial section 108 of the banjo nipple 102 is equipped with tracks 1 12 for the fixation of the sealing elements 106. The end section 1 10 of the pipe 104 has a flange 1 16 directed toward the pipe's 104 central axis 1 14, which engages in an outer track 1 18 formed in the banjo nipple's 102 substantially axial section 108. Following connection of the pipe 104 on the substantially axial section 108 of the banjo nipple 102, the end section 120 of the pipe 104 is clamped in the direction toward the central axis 1 14 of the pipe 104 and into the outer track 1 18, so that the flange 1 16 is formed. The flange 1 16 keeps the banjo nipple 102 in its place in the pipe 104 when the coupling device 101 is not fixed to any apparatus. The banjo nipple 102 and the pipe 104 are connected so that the banjo nipple 102 and the pipe 104 may be shifted axially and turned in relation to each other along the sealing elements 106. The axial displacement in the end section 1 10 of the pipe 104 is limited by, on the one hand, a transition 122 between the larger and the smaller inner diameter of the pipe 104 and, on the other hand, the outer track's 1 18 axial extension in the banjo nipple's 102 substantially axial section 108. The banjo nipple 102 and the pipe 104 may be turned in relation to each other, since both the end section 1 10 of the pipe 104 and the substantially axial section 108 of the banjo nipple 102 have a circular cross section. The substantially axial section 108 of the banjo nipple 102 is designed as a barrel and its exte- rior thus has spherical surfaces. The spherical surfaces are at the same time sufficiently plane for the sealing elements 106 to be able to seal between the banjo nipple's 102 substantially axial section 108 and the end section 1 10 of the pipe 104. The spherical surfaces in the substantially axial section 108 of the banjo nipple 102 may abut and turn toward the inside of the end section 1 10 of the pipe 104, which entails that the banjo nipple's 102 centre line 1 15 and the pipe's central axis 1 14 may be angularly displaced at an angle a, in accordance with Fig. 1 b. The angle a is preferably between 3-5 degrees. In this manner, a coupling device is achieved which is flexible in all directions, which entails easy fitting.

Fig. 2 shows the coupling device 101 in a cross-sectional view along the line I - I in Fig. 1 a. Fig. 2 shows how a screw 124 connects the banjo nipple 102 with an apparatus 126. The screw 124 is designed with a channel 128 extending along the shaft 130 of the screw 124 and culminating at the end 134 turned from the head 132 of the screw 124. The channel 128 in the screw 124 also extends radially in relation to the screw's 124 longitudinal shaft 136 through one or several diametrical drillings 138 in the screw's 124 shaft 130. The substantially axial section 108 of the banjo nipple 102 is equipped with a substantially axial channel 140, one end 142 of which culminates in the pipe 104 con- nected to the banjo nipple 102 and the other end 144 of which culminates in a substantially circular space 146, which is limited by the screw 124 and a substantially circular wall 148 of the banjo nipple 102. The screw 124 extends through a substantially circular hole 150 in the banjo nipple 102. Two sealing plates 152 are located on each side of the banjo nipple 102 in order to prevent leakages of fluid from the banjo nipple's 102 circular hole 150. Fluid is thus allowed to flow through the pipe 104, into the substantially axial channel 140 of the banjo nipple 102, further along to the substantially circular space 146 in the banjo nipple 102, into the channel 128 of the screw 124 in order to finally be led into a channel 154 inside the apparatus 126. Depending on the area of application for the coupling device 101 , the fluid may consist of air, petrol, diesel oil, engine oil or transmission fluid. For example, the pipe 104 may consists of a fuel pipe and the apparatus 126 may consist of a combustion engine, where the fuel pipe is comprised in a fuel system for the combustion engine.

Fig. 3 shows a coupling device 201 in a cross-sectional view according to a second embodiment. The coupling device 201 comprises a banjo nipple 202, a pipe 204 and two sealing elements 206, which are designed to abut against the banjo nipple 202 and the pipe 204. The sealing elements 206 preferably have different material properties. The sealing elements 206 are suitably arranged at a distance from each other and envelop a part of a substantially axial section 208 of the banjo nipple 202. For example, the sealing elements 206 may consist of O-rings. One end section 210 of the pipe 204 envelops the sealing elements 206 and at least one part of the substantially axial section 208 of the banjo nipple 202. The end section 210 of the pipe 204 has a larger inner diameter compared with the inner diameter of the remainder of the extension of the pipe 204. The substantially axial section 208 of the banjo nipple 202 is equipped with tracks 212 for the fixation of the sealing elements 206. The end section 210 of the pipe 204 has a flange 216 directed toward the pipe's 204 central axis 214, which engages in an outer track 218 formed in the banjo nipple's 202 substantially axial section 208. Following connection of the pipe 204 on the substantially axial section 208 of the banjo nipple 202, the end section 220 of the pipe 204 is clamped in the direction toward the central axis 214 of the pipe 204 and into the outer track 218, so that the flange 216 is formed. The flange 216 keeps the banjo nipple 202 in place in the pipe 204 when the coupling device 201 is not fitted. The banjo nipple 202 and the pipe 204 are connected so that the banjo nipple 202 and the pipe 204 may be shifted axially and turned in relation to each other along the sealing elements 206. The axial displacement in the end section 210 of the pipe 204 is limited by, on the one hand, a transition 222 between the larger and the smaller inner diameter of the pipe 204 and, on the other hand, the outer track's 218 axial extension in the banjo nipple's 202 substantially axial section 208. The banjo nipple 202 and the pipe 204 may be turned in relation to each other, since both the pipe 204 and the substantially axial section 208 of the banjo nipple 202 have a circular cross section. The end section 210 of the pipe 204 is designed so that it has a waistline. The inner diameter of the end section 210 thus decreases from one end of the end section 210 and in towards the middle of the end section 210, following which the inner diameter again increases toward the other end of the end section 210. The inside of the pipe's 204 end section 210 thus has spherical surfaces, against which the substantially axial section 208 of the banjo nipple 202 may abut and turn. In this manner, an angular displacement is achieved between the banjo nipple's central line 215 and the pipe's 204 central axis 214.

Fig. 4 shows a coupling device 301 in a cross-sectional view according to a third embodiment. The coupling device 301 comprises a banjo nipple 302, a pipe 304 and one sealing element 306, which is designed to abut against the banjo nipple 302 and the pipe 304. A substantially axial section 308 of the banjo nipple 302 envelops an end section 310 of the pipe 304 and the sealing element 306. The sealing element 306 suitably consists of an O-ring. The banjo nipple 302 and the pipe 304 are connected so that the banjo nipple 302 and the pipe 304 may be shifted axially and turned in relation to each other along the sealing element 306. The banjo nipple 302 and the pipe 304 may be turned in relation to each other, since both the end section 310 of the pipe 304 and the substantially axial section 308 of the banjo nipple 302 have a circular cross section. The banjo nipple 302 is designed so that the inner diameter of the banjo nipple's 302 substantially axial section 308 decreases from one end of the substantially axial section 308 in towards its middle, following which the inner diameter increases from the middle and out towards the other end of the substantially axial section 308. The inside of the substantially axial section 308 thus has spherical surfaces, against which the outside of the pipe's 304 end section 310 may abut and turn. In this manner, an angular displacement is achieved between the banjo nipple's 302 central 315 line and the pipe's 304 central axis 314. The substantially axial section 308 of the banjo nipple 302 is equipped with a track 312 for fixing of the sealing element 306. The track 312 is suitably formed on the part of the inside of the substantially axial section 308 with the smallest inner diameter.

Fig. 5 shows a coupling device 401 in a cross-sectional view according to a fourth embodiment. The coupling device 401 comprises a banjo nipple 402, a pipe 404 and two sealing elements 406, which are designed to abut against the banjo nipple 402 and the pipe 404. The substantially axial section 408 of the banjo nipple 402 is equipped with tracks 412 for fixing of the sealing elements 406. The substantially axial section 408 of the banjo nipple 402 envelops an end section 410 of the pipe 404 and the sealing elements 406. The banjo nipple 402 and the pipe 404 are connected so that the banjo nipple 402 and the pipe 404 may be shifted and turned in relation to each other along the sealing elements 406. The banjo nipple 402 and the pipe 404 may be turned in relation to each other since both the pipe 404 and the substantially axial section 408 of the banjo nipple 402 have a circular cross section. The banjo nipple 402 has a flange 416 directed towards the central axis 414 of the pipe 404. Following connection of the pipe 404 on the substantially axial section 408 of the banjo nipple 402, the end section 420 of the banjo nipple is clamped in the direction toward the central axis 414 of the pipe 404, so that the flange 416 is formed. The axial displacement in the substantially axial section 408 of the banjo nipple 402 is limited, on the one hand, by the flange 416 and, on the other hand, by the inner diameter of the substantially axial section 408 of the banjo nipple 402. The end section 410 of the pipe 404 is designed like a barrel. The exterior of the end section 410 thus has spherical surfaces, which may abut and turn toward the inside of the substantially axial section 408 of the banjo nipple 402. In this manner, an angular displacement is achieved between the banjo nipple's 402 central line 415 and the pipe's 404 central axis 414. The components and features specified above may within the framework of the invention be combined between different embodiments specified.

Claims

PATENT CLAIMS

1 . Coupling device comprising a banjo nipple (102, 202, 302, 402), a pipe (104, 204, 304, 404) and at least one sealing element (106, 206, 306, 406), designed to abut against the banjo nipple (102, 202, 302, 402) and the pipe (104, 204, 304, 404), where the banjo nipple (102, 202, 302, 402) has a substantially axial section (108, 208, 308, 408) with a central line (1 15, 215, 315, 415), the pipe (104, 204, 304, 404) has a central axis (1 14, 214, 314, 414) and an end section (1 10, 210, 310, 410), the end section (1 10, 210, 310, 410) of which is connected to a part of the substantially axial section (108, 208, 308, 408) of the banjo nipple (102, 202, 302, 402), characterised in that the banjo nipple (102, 202, 302, 402) and the pipe (104, 204, 304, 404) are movably connected to each other, so that the banjo nipple's (102, 202, 302, 402) central line (1 15, 215, 315, 415) and the pipe's (104, 204, 304, 404) central axis (1 14, 214, 314, 414) may be angularly displaced in relation to each other with an angular displacement (a).

2. Coupling device according to claim 1 , characterised in that the angular displacement (a) between the banjo nipple's (102, 202, 302, 402) central line (1 15, 215, 315, 415) and the pipe's (104, 204, 304, 404) central axis (1 14, 214, 314, 414) is between 1 -10 degrees, preferably 3-5 degrees.

3. Coupling device according to claim 1 or 2, characterised in that the pipe's (104, 204) end section (1 10, 210) envelops a part of the substantially axial section (108, 208) of the banjo nipple (102, 202) and the at least one sealing element (106, 206).

4. Coupling device according to any of the previous claims, characterised in that the pipe's (104, 204) end section (1 10, 210) has a larger inner diame- ter compared to the inner diameter of the pipe's (104, 204) remaining extension.

5. Coupling device according to any of the previous claims, characterised in that the pipe's (104, 204) end section (1 10, 210) is equipped with a flange (1 16, 216) directed toward the central axis (1 14, 214) of the pipe (104, 204), which engages in an outer track (1 18, 218) formed in the substantially axial section (108, 208) of the banjo nipple (102, 202).

6. Coupling device according to any of the previous claims, characterised in that the banjo nipple's (102) substantially axial section (108) has the shape of a barrel.

7. Coupling device according to any of claims 1 -5, characterised in that the pipe's (204) end section (210) has a waistline.

8. Coupling device according to claim 1 or 2, characterised in that a part of the banjo nipple's (302, 402) substantially axial section (308, 408) envelops the pipe's (304, 404) end section (310, 410) and the at least one sealing element (306, 406).

9. Coupling device according to any of claims 1 , 2 or 8, characterised in that the inside of the substantially axial section (308) of the banjo nipple (302) has spherical surfaces.

10. Coupling device according to any of claims 1 , 2 or 8, characterised in that the end section (410) of the pipe (404) has the shape of a barrel

1 1 . Coupling device according to any of the previous claims, characterised in that the banjo nipple (102, 202, 302, 402) and the pipe (104, 204, 304, 404) are connected so that they may be displaced axially.

12. Coupling device according to any of the previous claims, characterised in that the banjo nipple (102, 202, 302, 402) and the pipe (104, 204, 304, 404) are connected so that they may be turned in relation to each other.

13. Coupling device according to claims 4, 5 and 1 1 , characterised in that the axial displacement in the end section (1 10, 210) of the pipe (104, 204) is limited, on the one hand, by a transition (122, 222) between the larger and the smaller inner diameter of the pipe (104, 204) and, on the other hand, by the axial extension of the outer track (1 18, 218) in the axial section (108, 208) of the banjo nipple (102, 202).

14. Coupling device according to any of the previous claims characterised in that the banjo nipple's (102, 202, 302, 402) substantially axial section (108, 208, 308, 408) is equipped with tracks (1 12, 212, 412, 412) for fixation of the at least one sealing element (106, 206, 306, 406).

15. Coupling device according to any of the previous claims characterised in that an additional sealing element (106, 206, 306, 406) is arranged in con- nection with the banjo nipple (102, 202, 302, 402) and the pipe (104, 204, 304, 404).

16. Coupling device according to any of the previous claims, characterised in that the at least one sealing element (106, 206, 306, 406) consists of an O- ring.

17. Coupling device according to any of the previous claims, characterised in that a third sealing element (106, 206, 306, 406) is arranged in connection with the banjo nipple (102, 202, 302, 402) and the pipe (104, 204, 304, 404).