WO2012172163A1

WO2012172163A1 - A clamp element and a clamp assembly for an exhaust duct system internal combustion engine, and an exhaust duct for an internal combustion engine

Info

Publication number: WO2012172163A1
Application number: PCT/FI2012/050537
Authority: WO
Inventors: Fabio Castellani; Massimo CATTARINUSSI; Alessandro De Sanctis; Luciano PERINEL; Igor ZUCCOLIN
Original assignee: Wärtsilä Finland Oy
Priority date: 2011-06-17
Filing date: 2012-05-31
Publication date: 2012-12-20
Also published as: FI20115614A0; CN203823287U; DE212012000108U1; FI20115614L

Abstract

Invention relates to a clamp element (2) for use in an exhaust duct system of an internal combustion engine which clamp element has a curved form in a plane and is provided with an inner surface with a first radial distance (r1) from a centre of curvature (10) over its length (12), and which clamp element is provided with a securing means (14) at its both ends for retaining a tensioning part (4) at its place when the tensioning part is in operational tension. The securing means (14) comprises an extension part (18) extending in radial manner from the first radial distance (r1) to a second radial distance (r2) into which securing means a space (20) is arranged for the tensioning part, which space opens to the radial direction in the plane of the curved clamp element (2). Invention relates also to a clamp assembly comprising two clamp elements.

Description

A clamp element and a clamp assembly for an exhaust duct system internal combustion engine, and an exhaust duct for an internal combustion engine

Technical field

[001 ] The invention relates a clamp element for use in an exhaust duct system of an internal combustion engine which clamp element has a curved form in a plane and is provided with an inner circular surface with a first radial distance from a centre of curvature over its length, and which clamp element is provided with a securing means at its both ends for retaining a tensioning part at its place when the tensioning part is in operational tension.

[002] The invention relates also to a clamp assembly comprising two such clamp elements. Further, the invention relates to an exhaust gas duct for an internal combustion engine.

Background art

[003] Piston engines produce hot exhaust gas is which is typically led away from an exhaust manifold of the engine through a piping system. The duct system is formed of a number of separate parts. It is known to connect such parts with each other by a clamp, which connects the ends of the connected parts of the duct system together. Such a clamp is shown in the abstract of patent publication JP 9228833 A. The clamp is in a form of an annular rim which has an opening for a locking bolt of a screw. DE 3908060 A1 discloses a pipe connection of two overlapping pipes for connecting pipes forming an exhaust pipe of a motor vehicle, the connection having an articulation element designed as a ring. [004] Publication DE 3908060 A1 discloses a clamp element for use in an exhaust duct system of an internal combustion engine which clamp element has a curved form in a plane and is provided with an inner circular surface with a first radial distance from a centre of curvature over its length, and which clamp element is provided with a securing means at its both ends for retaining a tensioning part at its place when the tensioning part is in operational tension, which securing means comprises an extension part extending in radial manner from the first radial distance to a second radial distance having a bore into which fastening bolts are arranged. This kind of arrangement results in difficulties in assembly because the bolts must be pushed through the bores requiring space for installation. The bolts also are subjected to considerable bending force in installation.

[005] There are some requirements for such clamps when used in an exhaust piping which must be met, such as easy installation and durability. [006] It is an object of the invention to provide a clamp assembly for an exhaust gas duct system of an internal combustion engine, which provides improved performance both in assembling- and operational-wise.

Disclosure of the Invention

Objects of the invention are substantially met by a clamp element for use in an exhaust duct system of an internal combustion engine which clamp element has a curved form in a plane and is provided with an inner circular surface with a first radial distance from a centre of curvature over its length and which clamp element is provided with a securing means at its both ends for retaining a tensioning part at its place when the tensioning part is in operational tension The securing means comprises an extension part extending in radial manner from the first radial distance to a second radial distance. It is characteristic in that a space is arranged into the securing means for the tensioning part, which space opens to the radial. According to an embodiment of the invention the securing means comprises a pair of radially extending support parts forming the space for the tensioning part between the support parts.

The support parts have advantageously a dimension in the direction of the rim of the clamp element which is greater than the distance between the support parts. The support parts are provided with a circumferential end against which the tensioning part rests when in operational position. The circumferential end of the support parts is provided with a notch for ensuring the position of the tensioning part. According to a preferred embodiment of the invention the notch is of circular shape.

The tensioning part comprises preferably a bolt having a thread at least at its one end and a head at its other end, and two support pieces through a hole of which the bolt is assembled. Additionally the support pieces and the notch in the circumferential end of the support part are provided with mating surfaces. The mating surfaces are advantageously circular.

According to an advantageous embodiment of the invention the mating sur- faces comprise a circular surface of the notch and a circular surface of the support pieces and that radius of curvature of notch surface is greater than the radius of curvature of surface of the support piece.

Invention relates also to a clamp assembly comprising two clamp elements arranged its ends facing each other and being connected to each other by two tensioning parts, which clamp elements have curved form in a plane and are provided with an inner circular surface with a first radial distance from a centre of curvature over its length and which clamp elements are provided with securing means at its both ends for retaining a tensioning part at its place when the tensioning part is in operational tension. The securing means comprises an extension part extending in radial manner from the first radial distance to a second radial distance into which securing means a space is arranged for the tensioning part, which space opens to the radial direction in the plane of the curved clamp element.

Preferably the clamp elements are identical.

Further the invention relates also to an exhaust gas duct for an internal combustion engine which duct comprises at least two part connected with each other by a clamp assembly comprising two clamp elements arranged its ends facing each other and being connected to each other by two tensioning parts, which clamp elements have curved form in a plane and are provided with an inner circular surface with a first radial distance from a centre of curvature over its length and which clamp elements are provided with securing means at its both ends for retaining a tensioning part at its place when the tensioning part is in operational tension. The securing means comprises an extension part extending in radial manner from the first radial distance to a second radial distance into which securing means a space is arranged for the tensioning part, which space opens to the radial direction in the plane of the curved clamp element. Advantageously the connection area of the exhaust gas duct parts is formed to accommodate the form of the inner surface of the clamp.

Brief Description of Drawings [007] In the following, the invention will be described with reference to the accompanying exemplary, schematic drawing, in which Figure 1 illustrates a clamp assembly according to an embodiment of the invention.

Detailed Description of Drawing

[008] Figure 1 and its enlarged view 1 a depicts schematically a clamp assembly 1 according to the invention comprising two clamp elements 2 and tensioning parts 4. The clamp element are particularly so called v-clamps. The clamp assembly is intended to be used to connect together the ends of two consecutive parts of an exhaust duct system of an internal combustion engine. Particularly the clamp assembly is arranged to be used in connection with pipes, prepared to be assemble with a v-clamp system, in presence of pres- sure and high internal temperatures. In a v-clamp system the inner surface of the clamp element is substantially of V- shaped.

[009] The clamp element 2 element has curved form in a plane. Preferably its inner surface 6 has a radius r1 defining a first radial distance from a centre of curvature 10 over the length 12 of the clamp element 2. The length spans preferably less than 180° angle in order to prevent contact between two opposite elements. The inner surface 6 is preferably formed so that in the axial direction X the first and the second edges 12, 12' have a smaller radius r1 than the region between them.

[0010] The clamp element 2 has been preferably designed so that when in operation it does not substantially bend i.e. the clamp element is a rigid clamp element. [001 1 ] The clamp element 2 is provided with a securing means 14 at its both ends for retaining a tensioning part 4 at its place when the tensioning part is in operational tension. The securing means is arranged to the clamp element 2 to hold the tensioning part 4 in its intended position and to transmit the tensioning force to the clamp element 2.

[0012] The securing means 14 comprises an extension part 18 extending in radial manner from the first radial distance r1 to a second radial distance r2. There is a space 20 is arranged into the securing means for the tensioning part 4, which space opens to the radial direction in the plane of the curved clamp element 2 i.e. the space opens outside the clamp element 2. [0013] The securing means comprises a pair of supporting parts 22 between which the tensioning part is arranged. The supporting parts are arranged at a distance from each other in axial direction x so that the tensioning part may be fitted between the parts 22 in guided manner. [0014] As shown in enlarged view 1 a the support parts 22 have a dimension D in the direction of the rim of the clamp element 2 which is greater than the distance between the support parts 22. This way the securing means is robust and the tensioning force is adequately transmitted to the clamp element 2. [0015] The support parts 22 are provided with a circumferential end 24 against which the tensioning part 4 rests when in operational position. There is additionally a notch 26 formed to the circumferential end 24 so that the tensioning part 4 may be secured to its place in the notch.

[0016] The tensioning part 4 comprises a bolt 16 having a thread at least at its one end and a head 32 at its other end. The threaded end is provided with two sequential nuts 30 when in use. This provides a rigid construction supporting the bolt. The threaded portion of the tensioning part is not shown since it is inside the nuts in the figure. The tensioning part 4 further comprises two support pieces 28 through a hole of which the bolt 16 is assembled. [0017] The extension part 18 of the clamp element 2 is preferably provided with a pair of support surfaces 27 for the tension elements forming the mating surfaces with the cylindrical outer surface of the support pieces 28.

[0018] This minimizes a risk excessive bending force on the tensioning part 4 that might take place from a non-parallel contact surfaces under bolt head 32 and nuts 30. The misalignment of the two opposing clamp elements 2 that might arise during assembly is automatically compensated by the possibility of the support piece 28 to rotate and realign freely with the tension element.

[0019] The surface receiving the tensioning force in the notch arranged to the extension part 18 is preferably of circular shape of its area resting against a support piece 28 of the tensioning part 4. Respectively, the support piece 29 has circular outer surface at least at its areas resting against the notch. Ad- vantageously a radius of curvature of the notch 26 is greater than the radius of curvature of the support piece 28.

[0020] The support pieces 28 and the notch 26 are provided with mating surfaces. Since the securing means 14 has the space 20 which opens outside the clamp element 2 the securing means 4 may be installed so that the nuts 30 of the bolt 16 are loosened so as to allow the support piece 28 to pass into the notch 26 one by one.

[0021 ] The clamp is advantageously used in connection with an exhaust duct system of an internal combustion engine. Preferably the clamp element is formed of steel durable in the high temperature application according to the invention.

[0022] In a clamp assembly two clamp elements are arranged its ends facing each other and connected to each other by two tensioning parts 4. Preferably the clamp elements are identical. [0023] While the invention has been described herein by way of examples in connection with what are, at present, considered to be the most preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but is intended to cover various combinations or modifi- cations of its features, and several other applications included within the scope of the invention, as defined in the appended claims.

Claims

1 . A clamp element (2) for use in an exhaust duct system of an internal combustion engine which clamp element has a curved form in a plane and is provided with an inner circular surface with a first radial distance (r1 ) from a centre of curvature (10) over its length (12), and which clamp element is provided with a securing means (14) at its both ends for retaining a tensioning part (4) at its place when the tensioning part is in operational tension, which securing means (14) comprises an extension part (18) extending in radial manner from the first radial distance (r1 ) to a second radial distance (r2), characterized in that a space (20) is arranged into the securing means for the tensioning part (4), which space opens to the radial direction .

2. A clamp element according to claim 1 , characterized in that the securing means comprises a pair of radially extending support parts (22) forming the space for the tensioning part (4) between the support parts.

3. A clamp element according to claim 2, characterized in that the support parts (22) have a dimension (D) in the direction of a rim of the clamp element (2) which is greater than the distance between the support parts (22).

4. A clamp element according to claim 2 or 3, characterized in that the support parts (22) are provided with a circumferential end (24) against which the tensioning part (4) rests when in operational position.

5. A clamp element according to claim 4, characterized in that the circumferential end is provided with a notch (26).

6. A clamp element according to claim 5, characterized in that the notch (26) is of circular shape.

7. A clamp element according to claim 1 , characterized in that the tensioning part (4) comprises a bolt (16) having a thread at least at its one end and a head (32) at its other end, and two support pieces (28) through a hole of which the bolt is assembled.

8. A clamp element according to claim 5, characterized in that the tensioning part (16) comprises a bolt (16) having a thread at least at its one end and a head at its other end, and two support pieces (28) through a hole of which the bolt is assembled and that the support pieces and the notch are provided with mating surfaces.

9. A clamp element according to claim 8, characterized in that the mating surfaces are circular.

10. A clamp element according to claim 8, characterized in that the mating surfaces comprise a circular surface of the notch and a circular surface of the support pieces and that radius of curvature of the surface of the notch (26) is greater than the radius of curvature of the surface of the support piece (28).

1 1 . A clamp assembly, comprising two clamp elements according to any- one of the preceding claims arranged its ends facing each other and being connected to each other by two tensioning parts.

12. A clamp assembly according to claim 1 1 , characterized in that the clamp elements are identical.

13. Exhaust gas duct for an internal combustion engine, which duct com- prises at least two parts connected with each other by means of a clamp assembly according to claim 1 1 or 12.