EP3123005B1

EP3123005B1 - Flexible conduit tube and a connecting device for use in exhaust systems

Info

Publication number: EP3123005B1
Application number: EP14713459.7A
Authority: EP
Inventors: Uwe WEBEL
Original assignee: SJM Co Ltd
Current assignee: SJM Co Ltd
Priority date: 2014-03-27
Filing date: 2014-03-27
Publication date: 2019-02-27
Anticipated expiration: 2034-03-27
Also published as: KR101933945B1; EP3123005A1; WO2015144229A1; KR20160145635A

Description

The present invention relates to a system comprising a tubular nozzle and a flexible conduit tube and a connecting device for the system for connecting a flexible conduit tube in an exhaust system.
Flexible conduit tubes for exhaust pipes are used to isolate or dampen general vibration and noise emitted from the engine to the rest of the exhaust piping. Additionally, the flexible conduit tube guides the exhaust gases from the engine towards the exhaust exit, so that the flexible conduit tube needs to be designed and assembled in a gas tight fashion.
DE 20 2012 008 100 U1 , EP 1 026 376 A2 , DE 299 01 957 U1 , DE 200 23 409 U1 discloses a system according the preamble of claim 1.
Such a flexible conduit tube is described in KR Application no. 10 2003 0074773 . The herein described flexible conduit tube is provided to be welded to connection parts on both axial end sections so as to arrange the flexible conduit tube within the gas flow of the exhaust gas.
The fixation by welding leads to certain structural requirements of the flexible conduit tube. It is provided with caps at its axial ends. These caps are provided to enable the fixation of the bellows member and the flexible member on the end sections of the flexible conduit tube. Further the cap has to provide the welding surface for the weld process.
During the welding process of the cap with the counter part, the material of the cap is partly melted and re-solidified. Therefore the cap is required to have a sufficient axial length so that enough material remains after the weld process in order to provide structural integrity and strength to the flexible conduit tube axial end sections.
In this welding process, the material is heated and a major part of its volume is cooled fast so that the material also develops internal stress or strain and may even change its form. The stress inside the cap may also be transferred to the connected parts, such as the bellows member. These parts and especially their interactions are important for the functionality of the flexible conduit tube. When these parts experience internal strain or stress, their vibration behavior changes so that they may not have the full functionality, or might even amplify noise and vibration in sections of the bandwidth.
Furthermore, the possible form change of the cap may lead to a different position of the flexible conduit tube in the assembled state within the exhaust pipe assembly and thus may even result to a different installation position in the product.
Also the weld process is known to produce weld spatter. During the welding, the flexible conduit tube and its surfaces therefore have to be monitored so that no weld spatter may come into contact and no heat damage may further distort the different parts involved. This also requires an increased quality control to avoid the delivery of a damaged flexible conduit tube.
The present invention has therefore the object to provide a connecting device which allows the use of a flexible conduit tube assembly without the given disadvantages.
The object is solved by a connecting device having the features of independent claim 1.
The flexibility of the conduit tube is therefore provided by the bellows member which can freely flex around an axis in a longitudinal direction. The nozzle allows the easy connection of the flexible conduit tube with further sub-assemblies in the exhaust system. With the funnel shape of the nozzle, there is a good contact in the connecting area which, in the meaning of extending in the radial outward direction, also provides a wide connection diameter. Thus, the gas that flows through the connection is not hindered. The flexible conduit tube can therefore be connected to further sub-assemblies without using the weld process. Without the use of the welding process, the risk of weld spatter is reduced so that the production effort is greatly minimized and at the same time, the quality control is less complex.
Moreover, the heat inducing process due to the weld connection is prevented and the flexible conduit tube is therefore not additionally stressed by heat induction of the welding process. Thus, any resulting deformation of form change due to the heat induction is also prevented. This also allows the production of the flexible conduit tube within smaller dimensional tolerances and/or with increased part outputs. Consequently, the produced flexible conduit tube will also have a lower failure rate during production. As the bellows member is usually provided with metal material, the risk of damaging or inducing stress to the bellows member is also reduced; thus, the full functionality of the flexible conduit tube can be achieved.
According to the invention, the funnel-shaped portion of the nozzle extends in the shape of a truncated cone in a radial outward direction. Due to the funnel-shaped portion and the tubular form, the nozzle has a high section modulus which offers good resistance against vibration and the noise emission. Due to the increased stiffness, the connection of the flexible conduit tube with the nozzle can be provided in a stable and permanent form.
In a further preferred embodiment, the nozzle comprises a continuous wall thickness of 0.5 mm to 3 mm, preferably of 1 mm to 2 mm, particularly of 1.5 mm. As the nozzle has standard wall thicknesses which are readily available for tube-shaped parts, the nozzle and the flexible conduit tube are easy to manufacture. Thus, the efficiency of the production is increased and production costs are minimized.
In an related example which is not claimed and is no part of the present invention but is useful to understand the invention, the nozzle is connected to an inner surface area of the flexible conduit tube. Thereby, the nozzle can be connected by insertion into the flexible conduit tube during the production process. Further, it is possible to arrange a pre-assembly condition wherein the nozzle part is simply inserted into the flexible conduit tube before being fixed to the flexible conduit tube. Thus the complexity of manufacturing is reduced.
According to the invention, the flexible conduit tube further comprises a cap having an annular shape and being provided on the axial end portions of the flexible conduit tube which has a sleeve member having an annular shape and being provided on the axial end portions of the conduit tube whereas the nozzle is directly connected to the bellows member and/or the sleeve member. In an related example which is not claimed but is useful to understand the invention, the flexible conduit tube further comprises a cap having an annular shape and being provided on the axial end portions of the flexible conduit tube which has a sleeve member having an annular shape and being provided on the axial end portions of the conduit tube whereas the nozzle is directly connected to the cap and/or the bellows member and/or the sleeve member. Therefore, the cap provides additional holding force of the bellows member in the assembled condition. Further, the sleeve member allows fixing additional sub-assemblies inside the flexible conduit tube so as to adapt the flexible conduit tube to special conditions during use inside the exhaust system. The nozzle can therefore be used to fix all the elements of the flexible conduit tube together namely the cap, the sleeve member and the bellows member. By fixing all the parts on the nozzle, the production and the complexity of the assembly process is reduced. According to the invention, the cap and the nozzle are provided in one piece. Due to the design as one piece, the inner diameter in the area of the nozzle and the cap can be further widened as there is no additional stacking of the layers of the nozzle and the cap in the radial direction necessary. This will further improve the gas flow as wider diameter is provided, and thus less resistance of the gas flow is ensured and the backpressure is kept low. Further, due to the one piece design, additional stress on the material is evenly distributed in the nozzle/cap part and thus evenly spread within the material boundaries. Consequently, a one piece design offers also high resistance against vibration as failure of the part is reduced.
In an related example which is not claimed and is no part of the invention but is useful to understand the invention, the sleeve member and the nozzle are provided in one piece. This design also offers an even distribution of the material stresses inside the nozzle/sleeve part. Moreover, the bellows member and the cap can be easily fixed on the radial outer surface area of the nozzle/sleeve part, and thus the complexity of the assembly process is reduced.
The flexible conduit tube further comprises an outer flexible member provided on the outside of the bellows member. The outer flexible member can be in direct contact with the bellows member and being placed between the cap and the bellows member on the axial ends of the flexible conduit tube whereas the cap, the outer flexible member, the bellows member and the sleeve member are fixed to the nozzle by welding, preferably by one welding seam. The use of the outer flexible member is therefore to provide noise cancellation due to vibration. The fixation together with all parts in one welding seam further reduces the production costs. In addition, by providing only one weld seam and thus only one welding process, the heat stress used in the welding process is also reduced. Hence, the material involved becomes less brittle and therefore hardens less and further shows a better vibration behaviour that results in better dampening ability of the material. Further, the center of mass of the flexible conduit tube is influenced so that a higher concentration of mass is provided to the end sections of the flexible conduit tube, thereby changing also the vibration behaviour.
The object is further solved by a connecting device with a system which further comprises a tubular counterpart configured to connect the flexible conduit tube which comprises a connecting portion which is in contact with the funnel portion of the nozzle, at least sectionwise, and a fixation member being in contact with the counterpart and the nozzle, so that the flexible conduit tube is fixed by form fit and/or force fit. The connecting device can therefore be realized without using a weld process to connect the flexible conduit tube with the counterpart which normally produces a thick additional weld seam and further requires high temperatures to ensure the full connection stability of the welding seam. The flexible conduit tube and the counterpart are connected and fixed to each other by the fixation member. The assembly can therefore be realized by connecting the flexible conduit tube with the counterpart and additionally providing the fixation member to fix these both parts together. With these features, a simple connection can be provided which does not require further welding process with the counterpart. The fixation member can also apply force on the counterpart and on the flexible conduit tube biasing both of them against each other. Therefore, both parts can be fixed together and are able to maintain the fixation even under vibration conditions. In case of a form fitting, it is possible to establish the connection with preformed-shaped parts so that a simple and reliable connection method can be provided. As the fixation member is in contact with the counterpart and the nozzle, it is therefore possible to apply the connecting force directly on the flexible conduit tube and the counterpart. This further enables the flow of force without inducing high shear stresses in the remainder of the connecting device. Both the nozzle and the counterpart can therefore be shaped on the sole purpose to hold the fixation forces, so that the construction of the remainder of the connecting device can be made with smaller wall thicknesses or different materials in order to reduce the overall weight.
In a further embodiment, the connecting portion of the counterpart is contacting the nozzle at least partially by a surface area contact. With the surface contact area, the vibration behaviour of the connecting device can be further improved and the dampening of vibration and noise is therefore enabled. Moreover, the high connection forces can be ensured in order to provide a gas-proof connection and also in order to provide a flow of material stress throughout a larger area and therefore reducing high stress peaks in the connecting area.
In another preferred embodiment, the connecting portion of the counterpart has a larger diameter than the adjacent portion of the counterpart. With the provision of a diameter change in the counterpart, the counterpart can be used to attach the fixation member to fix both the counterpart and the nozzle together.
According to the invention, the connecting portion of the counterpart has at least in a section a convex shape in the shape of two truncated cones which are joined at their bases. Due to the truncated cone shape, the connecting portion can thus be realized out of standard tubular parts and are easy to manufacture. In addition, as the truncated cone shape extends in the radial direction, the connecting area of the nozzle and the counterpart provides a larger diameter and therefore does not reduce the current of the gas flow in the exhaust system. In another preferred embodiment, the counterpart is contacting the funnel-shaped nozzle in the inner surface area, thus reducing the complexity of the assembly.
In another embodiment, the counterpart has an inner centering on its end which extends into the nozzle. The centering provides improvement of the assembly process as both the counterpart and the nozzle are easily fixed together. Further, it is possible to position the counterpart in the nozzle with a high degree of accuracy so that a high quality gas-proof connection can be established with reduced complexity.
In a further preferred embodiment, the fixation member has a convex shape in the circumferential direction so that the fixation member is contacting the counterpart and the nozzle at least sectionwise. Therefore, the fixation member can be easily fixed directly on the outside surface in the connection area and does not induce additional stress due to shear, as the flow of the force is short and direct into the connecting portion.
Figures 1 and 2 do not belong to the invention, but are useful to understand the present invention.
Figure 1 which does not belong to the present invention, but is useful to understand the present invention, shows in a cut view the setup of an example of the connecting device.
The connecting device 7 consists of three separate assemblies or parts. These are the flexible conduit tube 1, the counter part 8 and the fixation member 9.
In Figure 1 which does not belong to the present invention, but is useful to understand the present invention, the flexible conduit tube 1 comprises a metal bellows member 2 being made of sheet metal. The bellows member 2 has in its axial direction along the flexible conduit tube 1 corrugated portions, which provide flexibility for vibration and dampening ability. At its axial ends, the bellows member 2 has cylindrical shaped portions without corrugated portions with which it is connected to the flexible conduit tube 1.
An outer flexible member 6 is provided on the outside of the bellows member 2. The outer flexible member 6 is made of a plurality of metal wires which are woven, braided or knitted, so that the outer flexible member 6 forms a flexible mesh. The outer flexible member 6 is in direct surface contact with the bellows member 2, especially at the corrugated portions. The outer flexible member 6 can move on the surface of the bellows member 2 in the area of the corrugated portions and is fixed to the flexible conduit tube 1 at axial end sections of the flexible conduit tube 1. The outer flexible member 6 completely surrounds the bellows member 2 in the circumferential direction at the section with the corrugated portions. At the axial end sections the outer flexible member 6 is reduced in its diameter so that it directly contacts the bellows member 2 on the cylindrical portions and is provided as a layer on top of the bellows member 2 in the radial direction of the flexible conduit tube 1.
On the axial end of the flexible conduit tube 1, a cap 4 is provided which is placed on top of the outer flexible member 6. The cap 4 is of an annular shape and thus surrounds the axial end portions of the flexible conduit tube 1. The cap 4 is made of sheet metal and contacts the outer flexible member 6 on an inner surface. The cap has an outer end being directed towards the end of the flexible conduit tube and an inner end. The cap 4 has towards its inner end a bending section such that a portion of the cap 4 is extending in the radial outward direction so that the inner end is placed on the radial portion of the cap 4.
On the axial end section of the flexible conduit tube 1 being radially inside the bellows member 2, the sleeve member 5 is provided. The sleeve member 5 contacts the bellows member 2 on a radially outside surface and further extends from the axial end section of the flexible conduit tube 1 in the axial direction inside the flexible conduit tube 1. The portion of the sleeve member 5 contacting the bellows member 2 is of a larger diameter than the axial portion of the sleeve member 5 within the flexible conduit tube 1. The sleeve member 5 is of annular shape and made of sheet metal. On the radially smaller axial portion, further sub-assemblies of the flexible conduit tube 1 can be fixed.
The nozzle 3 is fixed inside the sleeve member 5. The nozzle has two portions which correspond to the portion being fixed inside the flexible conduit tube 1 and to the outer end portion. The outer end portion of the nozzle 3 has a funnel shape so that it radially widens towards its outer end. The funnel has a linear shape so that the outer surface resembles the form of a truncated cone. The nozzle itself is made of a tubular part and has an annular shape and is also made of sheet metal. The portion of the nozzle 3 inside the sleeve member 5 has a cylindrical form and extends in parallel to the center axis of the flexible conduit tube 1. Further, the nozzle 3 is fixed to the sleeve member 5 by welding so that with one circular welding seam also the bellows member 2, the outer flexible member 6 and the cap 4 are connected to each other and form a gas proof connection.
The counterpart 8 is formed on an exhaust side and is inserted into the nozzle 3. The counterpart 8 is of annular shape and has a tubular form. The counterpart 8 has in its outer end which is inserted into the nozzle 3, a centering collar which abuts against the cylindrical part of the nozzle 3. Adjacent to the centering portion, the counterpart 8 has a convex portion consisting of a radial extension. The convex portion is shaped so that it forms a radially outward extending surface and a radially inward extending surface. The convex portion is radially extending in a linear shape so that its outer surface has the form of two truncated cones being connected at their bases. Further, the angle of the radial extension matches with the angle of the funnel shaped portion of the nozzle 3. When the counterpart 8 is inserted into the nozzle 3, the side of the convex portion facing the outer end abuts against the inner surface of the nozzle 3 and forms a surface area contact.
In this state, the fixation member 9 is placed on the radial outside surfaces of both the nozzle 3 and the counterpart 8. The fixation member 9 is of annular shape and made of sheet metal and has a convex shape in the circumferential direction. Thus, it is shaped to match the outside surfaces of the nozzle 3 and of the convex portion side of the counterpart 8 facing away from its outer end. The fixation member 9 has no closed circumference but can be first placed on the connecting device 7 and then tightened around it by a screw connection which reduces its inner diameter. Thus, by the radial pressure provided from the fixation member 9, the nozzle 3 and the counterpart 8 are pressed axially against each other and form a gas proof surface area contact.
With this connecting device, the connection is established with the counterpart 8 without an additional welding process. The angle of the nozzle 3 and its funnel portion as well as the angle of the connecting portion of the counterpart 8 and of the fixation member 9 may have a wide range of angle degree as long as the sufficient amount of actual force is induced into the connection from the fixation member 9.
As the welding process is omitted, especially the funnel portion of the nozzle 3, the end portion of the counterpart 8 and the fixation member 9 do not have to be designed for welding purposes. This further means that the design of these parts does not need to include additional material for the necessary heat transfer. Further, they are free of possible form changes due to the heat stress normally induced by a welding process.
Due to the shape and design of the nozzle 3 and the counterpart 8, the connection due to the elasticity of the connection portion of the counterpart 8 and the nozzle 3 also applies an axial force when connected and fixed by the fixation member 9. With this elasticity in the axial direction of the connecting device 7, a spring-like system is created. The system therefore presses against the fixation member 9 and against the contact surface between the counterpart 8 and the nozzle 3. The pressure further realizes additional stability against vibration and dampens the excitation and noise.
Further, the shape of the fixation member 9 will ensure self centering on the connection portion of the counterpart 8 and the nozzle 3 and this further improves the quality of the connecting device 7 as a failed placement is avoided.
The only welding seam of the connecting device 7 is placed on the outer surface of the nozzle 3 and fixes together the bellows member 2, the outer flexible member 6, the cap 4 and the sleeve member 5. Therefore, the assembly process is simplified and the heat stress of the assembly is reduced, as only one heating and cooling down phase is applied. Further, the assembly of the involved parts is placed outside of the nozzle 3 diameter and allows the exhaust gas to flow without obstacles or narrow passages and enables a maximized current flow.
Instead of welding, the assembly can also be realized by riveting, screwing or soldering. Therefore, the heat stress on these parts can be further reduced or avoided completely.
By the connection of the connecting device 7, the overall length of the counterpart 8 together with the flexible conduit tube 1 in the axial direction can be reduced. The connection by using the fixation member 9 allows shortening of the axial lengths of the cap 4, the sleeve member 5, the outer flexible member 6 and the bellows member 2. This is possible as the welding is omitted thereby avoiding the welding heat, which makes it necessary to enlarge the involved parts, to distribute the welding heat more evenly through the assembly and to avoid certain overheated regions. Also the risk of weld spatter is reduced so that the distance of the flexible conduit tube 1 to the connection can be reduced, and thus the axial build length is also reduced, allowing the integration of the connecting device 7 in smaller assemblies or exhaust systems.
According to the invention, the nozzle 3 and the cap 4 can be made of one part. The radial height of the assembly therefore decreases in the section of the axial ends of the flexible conduit tube 1 and makes it possible to further reduce the necessary space required when connected to the counterpart 8. This also reduces the volume of the welding seam and therefore requires less energy and further reduces production cost and time. This also improves the quality of the connecting device 7 as a failure of that omitted part is impossible. The welding seam is therefore provided on the inside of the flexible conduit tube 1 and is protected from environmental influences. Also, in case where the visibility of the welding seam is not preferred, this will further improve the visual appearance of the connecting device 7. The bellows member 2 serves generally as the gas tight barrier of the flexible conduit tube 1. Thus, by providing an outer circumferential one piece part such as the nozzle/cap part, the gas proof connection quality is further improved as the nozzle/cap part itself provides the gas proof by its material.
In another related example which is not claimed but is useful to understand the invention , the nozzle 3 and the sleeve member 5 are made of one piece. This also reduces the size of the welding seam and places all parts on the radial outside of the nozzle/sleeve member part. With this example, the innermost diameter of the connecting device 7 can be easily set without further reducing the diameter during assembly.
Figure 2 shows an related example which is not claimed but is useful to understand the invention, which represents the flexible conduit tube 1 as also shown in Figure 1. The flexible conduit tube 1 has the nozzle 3 attached on one axial end so that this end is further connected to the counterpart 8. It is further possible to provide the nozzle 3 on both axial ends so to be able to use the weld-free connection on both sides and to further minimize the need for welding. In Figure 2, the bellows member 2 extends along the axial length of the flexible conduit tube 1 and is enclosed by the outer flexible member 2. In addition to Figure 1, a metal hose is attached to the sleeve member 5 which also extends over the axial length of the flexible conduit tube 1. It is also possible to use the connecting device 7 or the flexible conduit tube 1 without either of the outer flexible member or the metal hose. Reference list

flexible conduit tube 1

bellows member 2

nozzle 3

cap 4

sleeve member 5

outer flexible member 6

connecting device 7

counterpart 8

fixation member 9

Claims

A connecting device (7) comprising:
a tubular counter part (8);

a fixation member (9); and

a system comprising a tubular nozzle (3) and a flexible conduit tube (1),

wherein the system is configured for use in exhaust systems,

wherein the flexible conduit tube (1) comprises:
a bellows member (2),

an outer flexible member (6) which is provided on the outside of the bellows member (2),

a cap (4) having an annular shape and being provided on the axial end portions of the flexible conduit tube (1), and

a sleeve member (5) having an annular shape,

wherein the cap (4) has towards its inner end a bending section such that a portion of the cap (4) is extending in a radial outward direction so that the inner end is placed on the radial portion of the cap (4), and the cap (4) is contacting the outer flexible member (6) on an inner surface,

wherein the sleeve member (5) is provided on the axial end portions of the flexible conduit tube (1) and whereas the nozzle (3) is directly connected to the bellows member (2) and/or the sleeve member (5),

wherein the tubular nozzle (3) is connected to the flexible conduit tube (1) in a gas proof manner and extends in a funnel shape on its end being opposite of the end connected to the flexible conduit tube (1),

wherein the cap (4) and the nozzle (3) are provided in one piece,

whereas the funnel shaped portion of the nozzle (3) extends in the shape of a truncated cone in a radially outward direction,

wherein the tubular counter part (8) is configured to connect the system, and comprises a connecting portion which is contacting with the funnel portion of the nozzle (3) at least section wise,

wherein the fixation member (9) is in contact with the counter part (8) and the nozzle (3) so that the system is fixed by form fit and/or force fit,

characterized in that

the connecting portion of counter part (8) has at least in a section a convex shape, in the shape of two truncated cones which are joined at their base.
Connecting device (7) according to claim 1, whereas the nozzle (3) comprises a continuous wall thickness of 0,5 mm to 3 mm, preferably of 1 mm to 2 mm, particularly of 1,5 mm.
Connecting device (7) according to claim 2, whereas the connecting portion of the counter part (8) is contacting the nozzle (3) at least partially by area surface contact.
Connecting device (7) according to any one of the claims 1 or 3, whereas the connecting portion of the counter part (8) has a larger diameter than the adjacent portion of the counter part (8).
Connecting device (7) according to claim1 , whereas the counter part (8) is contacting the nozzle (3) on an inner surface area.
Connecting device (7) according to claim 1, whereas the counter part (8) has an inner centering on its end which extends into the nozzle (3).
Connecting device (7) according to 1, whereas the fixation member (9) has a convex shape in the circumferential direction so that the fixation member (7) is contacting the counter part (8) and the nozzle (3) at least section wise.