Abstract:
A combustion engine component comprises an assembly of a belt pulley for driving auxiliary engine equipment and a torsional vibration damper. The assembly is adapted to be fixed on an engine crankshaft, wherein the belt pulley is of a so called decoupling type, arranged to be able to change its rotational angle relative to the crankshaft and the torsional vibration damper. The torsional vibration damper is partially positioned in a corresponding annular recess in the belt pulley, creating an annular cavity in the recess between the torsional vibration damper and the belt pulley. An annular seal ring is positioned in the annular cavity and is arranged to close off at least a part of the annular cavity from the air surrounding the assembly.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims foreign priority benefits under 35 U.S.C. §119(a)-(d) to European patent application number EP 13176760.0, filed Jul. 17, 2013, which is incorporated by reference in its entirety. 
     TECHNICAL FIELD 
     The current disclosure relates to a combustion engine component comprising an assembly of a belt pulley for driving auxiliary engine equipment and a torsional vibration damper. The assembly is adapted to be fixed on an engine crankshaft, wherein the belt pulley is arranged to be able to change its rotational angle within limits relative to the crankshaft and the torsional vibration damper, and wherein the torsional vibration damper has an annular portion being positioned in a corresponding annular recess in the belt pulley, creating an annular cavity in the recess between the torsional vibration damper and the belt pulley. 
     BACKGROUND 
     In modern cars it is essential to minimize the space occupied by each of the car components, especially under the hood, since the number and complexity of not the least auxiliary equipment needed has increased during the last decades and the design of the car leaves limited space. Many components have therefore been designed to share the space effectively under the hood, especially components being more or less cooperating with each other. 
     The demand for both comfort and durability has also increased, encouraging the engineers to find solutions both to noise elimination and to wear problems. 
     Two component types that have been redesigned in parallel in order to save space, both being mounted on the same crankshaft end, include on the one hand torsional vibration dampers, TVDs, and on the other hand belt pulleys for driving auxiliary equipment like generators, water pumps, a/c pumps and servo steering pumps. They thus can come as an assembly, ready to be mounted on the end of an engine crankshaft as one component. 
     The above mentioned two components can be relatively tightly arranged adjacent each other, but since a modern belt pulley intended to drive auxiliary components from the crankshaft is equipped with means for dampening or decoupling the vibrations and oscillations of the crank shaft from the belt and the auxiliary equipment, the TVD and the belt pulley must leave a little space in between, allowing the belt pulley to change its rotational angle relative to the TVD. There is a cavity between the two components in the assembly, and the cavity can be the source of noise within the hearing range for a human being when the engine is running. In order to dampen noise from this type of assembly it is known to place caps or houses over the entire assembly, a non-wanted space consuming car component. 
     SUMMARY 
     The present disclosure relates to a combustion engine component, an assembly of a torsional vibration damper and a belt pulley, according to the above, which assembly comprises an annular seal ring, positioned in an annular cavity located between the TVD and the belt pulley, the seal ring being arranged to close off at least a part of the annular cavity from the air surrounding the assembly. 
     The annular seal member not only effectively dampens noise generated in the cavity but also prevents dirt from entering the cavity, thus prolonging the life of the assembly. 
     In a first embodiment of the disclosure, wherein the torsional vibration damper has a second mass positioned mainly in the recess, and wherein the belt pulley has a spring house, a radial carrier flange and a belt face portion, carried by the radial carrier flange, which all together are forming the recess, an annular first type seal ring is arranged, comprising an annular, axially extending, first type sealing lip sealing against the belt face portion, and an annular, radially extending, second type sealing lip, sealing against the radial carrier flange and an annular, supporting middle seal section, joining the first and second type sealing lips and sealing against the second mass. The first type seal ring can be floatingly arranged in the annular cavity. This first type of seal ring can be made from a relatively simple tool and in production it is possible to inspect that it has been installed, e.g., with a vision system. 
     In a second embodiment of the disclosure, wherein the torsional vibration damper has a second mass, positioned mainly in the recess, an annular, second type seal ring is arranged, comprising an annular, first type fastening portion, attached in the recess, which first fastening portion has an annular, axially extending third type sealing lip, which is designed to radially meet and slidingly seal against the second mass. This second type seal ring can also be made from a relatively simple tool, is possible to inspect that it has been installed and can be press fit. 
     In a third embodiment of the disclosure, wherein the torsional vibration damper has a secondary mass carrier portion, positioned mainly in the recess, a third type seal ring is arranged, comprising an annular first type fastening portion, attached in the recess, which first fastening portion has an annular, radially extending fourth type sealing lip, which is designed to axially meet and slidingly seal against the secondary mass carrier portion. Also this third type seal ring can be made from a simple tool, is possible to inspect that it has been installed and can be press fit. It seals against the torsional vibration damper hub, which is still in axial direction of the crankshaft. 
     In a fourth embodiment of the disclosure, being a combination of the second and third embodiment and wherein the torsional vibration damper has a second mass and a hub secondary mass carrier portion, positioned mainly in the recess and carrying the second mass, an annular, forth type seal ring is arranged, comprising an annular, first type fastening portion, attached in the recess, which first fastening portion has an annular, axially extending third type sealing lip, designed to radially meet and slidingly seal against the second mass and an annular, fourth type sealing lip, radially extending from the first type fastening portion, the fourth type sealing lip being designed to be biased to axially meet and slidingly seal against the hub secondary mass carrier portion. The fourth type seal ring can also be inspected to see if it has been installed, can be press fit and seals double. It seals against the torsional vibration damper hub, which is still in axial direction of the crankshaft. 
     Finally, in a fifth embodiment of the disclosure, wherein the torsional vibration damper has a hub secondary mass carrier portion, positioned mainly in the recess, and wherein the belt pulley has a radial carrier flange, carrying a belt face, an annular fifth type seal ring is arranged, comprising an annular second type fastening portion, attached to the hub secondary mass carrier portion. The second type fastening portion has an annular, radially extending fifth type sealing lip, which is designed to be biased and slidingly seal against the radial belt face carrier flange. This fifth type seal ring can be made from a simple tool, can be press fit and it seals against the torsional vibration damper hub, which is still in axial direction of the crankshaft. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Some examples according to the disclosure will in the following be explained with reference to the accompanying drawings. 
         FIG. 1  shows schematically a combustion engine with an assembly of the type concerned: 
         FIG. 2  shows a first embodiment of an assembly according to the disclosure in a broken cross section, at a small angle from the side; 
         FIG. 3  shows the same embodiment as shown in  FIG. 2  but in a straight cross section; 
         FIG. 4  shows a second embodiment of the disclosure in a broken cross section; 
         FIG. 5  shows a third embodiment of the disclosure in a broken cross section; 
         FIG. 6  shows a fourth embodiment of the disclosure in a broken cross section; and 
         FIG. 7  shows a fifth embodiment of the disclosure in a broken cross section. 
     
    
    
     DETAILED DESCRIPTION 
     As required, detailed embodiments are disclosed herein. However, it is to be understood that the disclosed embodiments are merely exemplary and that various and alternative forms may be employed. The figures are not necessarily to scale. Some features may be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art. 
     As can be seen In  FIG. 1 , the disclosure relates to a component assembly for a combustion engine  1 , shown schematically. The engine  1  is connected to a gear box  2  at a rear end and to a component assembly  3  according to the disclosure at a front end. As an example, the engine has six cylinders, each with a piston  4  and a piston rod  5 , all schematically shown. The piston rods are connected to an engine crankshaft  6 , shown schematically as a center line only, the arrangement being well known. Underneath, the engine is equipped with an ordinary oil pan arrangement  7 . The component assembly  3  is mounted on the crankshaft  6 , arranged to rotate with it, positioned at the crankshaft front end  8 , and comprises a torsional vibration damper, a TVD,  9 , and a belt pulley  10 , the latter being in position to drive a belt  11 , which in turn is arranged to drive auxiliary equipment mounted on the engine like a generator  12  and other equipment not shown, e.g., a steering servo pump, an A/C compressor or a water pump. 
     In  FIG. 2  the component assembly  3  of  FIG. 1  is shown more in detail, displaying a first embodiment of the disclosure, shown in broken cross section and seen at a small angle from what is the engine side, when mounted. The assembly  3  comprises a so called TVD, a Torsional Vibration Damper,  9 , which comprises a TVD hub  13 , a mainly axially extending, annular TVD secondary mass  14  and an axially extending secondary mass carrier portion  15  of the TVD hub  13 . Although shown in cross section, the TVD  9  and the belt pulley  10  are of course in reality mainly rotationally symmetrical, in order to function properly. Between the secondary mass carrier portion  15  and the secondary mass  14  a mainly axially extending annular resilient ring  16  is located, which annular resilient ring  16  is bonding the TVD hub secondary mass carrier portion  15  and the TVD secondary mass together. This is in principal a quite common TVD design. 
     The assembly  3  also comprises a pulley, a belt pulley  10  of the so called decoupled type. The belt pulley  10  has a belt pulley first hub member  17  and a belt pulley second hub member  18  which are connected as a unit to the TVD hub  13  with assembly bolts  19 , of which only one is shown. On the outside of the assembly, seen from the engine side, an assembly plate member  20  is also included in the bolted assembly. The belt pulley first hub member  17  is designed with two diametrically positioned driver fingers  21 , of which only one is shown in the figure, which fingers have a function which will be disclosed in the following. 
     The belt pulley  10  further comprises a spring house  22 , which is housing two curved coil springs  23  (only one is shown here). The spring house  22  is arranged on a plain bearing  24 , which is arranged coaxially around the belt pulley second hub member  18 . The driver fingers  21 , the curved coil springs  23 , coil spring end supports  22   a , integrated in the spring house  22 , all cooperate in a decoupling function such that the spring house  22  is driven by the driver fingers  21  via the coil springs  23 , all in a known way, to get the decoupling function. The spring house  22  thus can change its radial angle within certain limits relative to the angle of the crankshaft  6 . This is for the man skilled in the art a known decoupling function which is arranged to reduce vibrations in the crankshaft rotation pattern from the belt and the belt pulley driven auxiliary equipment. 
     The spring house  22  is kept in position axially on the bearing  24  with the aid of an annular disc spring  25 , positioned between the spring housing  22  and the TVD hub  13 , and an annular washer  26 , positioned between the spring housing  22  and an end flange  27  on the belt pulley second hub member  18 . 
     Radially and coaxially, the spring house  22  is carrying a pulley belt face portion  28 , which belt face portion  28  is arranged at a distance from the spring house  22 , carried by a radial belt face carrier flange  29 , extending radially from the spring house  22 , thus creating a recess  30 , located radially outside the spring house  22 , beside the radial carrier flange  29  and radially inside the pulley belt face portion  28 . 
     In the recess  30  the lion&#39;s part of the TVD secondary mass  14 , the annular resilient ring  16  and the axially extending secondary mass carrier portion  15  of the TVD hub  13  is located. Because the belt pulley spring house  22  is arranged to be allowed to change its rotational angle relative to the crankshaft  6  and thus the TVD  9 , there must be a certain play between the walls of the recess  30  and the parts of the TVD secondary mass  14 , the annular resilient ring  16  and the top portion  15  of the hub  13  being located in the recess, i.e., a cavity  30   a  is present there between. The cavity  30   a  runs mainly radially from the disc spring  25 , mainly axially past the spring house  22 , past the recess  30  and the parts of the TVD being positioned in the recess  30 . Since the TVD  9  and the belt pulley  10  are mounted on the end of the engine crankshaft  6 , the different parts that are defining the cavity are exposed to a lot of vibration, both axially and radially, making the cavity  30   a  change its form slightly, i.e., oscillate. Thus noise can be generated, the noise being sometimes containing frequencies within the hearing range of man. In order to dampen noise, which can be generated in the cavity  30   a , a first type, annular seal ring  31  is located in the cavity  30   a . The seal ring on the one hand stops noise from escaping the cavity  30   a , which noise can disturb human beings and animals in the vicinity of or in the vehicle, and on the other hand, stops dirt from collecting in the cavity. 
     In  FIG. 3 , where applicable, the details shown and discussed below are denoted with the same reference numbers as in  FIGS. 1 and 2  for showing the corresponding details present. In  FIGS. 4-7  only the reference numbers discussed are repeated, since the  FIGS. 3-7  are alike except from different embodiments of the annular seal ring. 
     As can be seen in  FIG. 3 , the annular seal ring  31 , being the same first type embodiment as shown in  FIG. 2 , positioned in the cavity  30   a , shows an annular, axially extending, first type sealing lip  32 , an annular, radially extending, second type sealing lip  33  and an annular, supporting middle seal section  34 , joining the first and second sealing lips  32  and  33  together. Both the first and second type sealing lips  32 ,  33  are designed to slidingly and sealingly meet the inner wall of the recess  30 , i.e., the radially inner surface  28   a  of the belt face portion and the axially inner surface  29   a  of the carrier flange  29 , respectively, while the supporting, middle seal section  34  meets sealingly against the TVD secondary mass  14 . The middle section  34  can be slidingly acting against the TVD secondary mass  14 , but can also be resting on it. The annular first type seal ring  31 , being of a resilient material, is designed to be slightly stretched or biased when mounted, so that the first and second sealing lips  32 ,  33  are pressed against and slidingly seal against the recess walls, supported by the middle seal section  34 , which is biased against the TVD secondary mass  14  by the sealing lips  32 ,  33 . Thus the cavity is sealed so that nothing should be able to enter or leave the cavity, being it noise generated inside or dirt coming from the outside. 
     The sealing effect is secured double, since there are two sealing lips. Again, the seal does not have to be fastened to either of its supporting surfaces, since it is trapped in the recess between the two parts, the TVD  9  on the one hand and the belt pulley  10  on the other hand. This kind of mounting can be called a floating mounting. The TVD  9  and the belt pulley  10  are also free to vary their relative rotating angle on the crankshaft, of course within the freedom ratio decided by the decoupling function of the belt pulley  10 . 
     In the  FIGS. 3-4  the driving belt  11  is also shown. The driving belt  11  and the belt face portion  28  are designed with corresponding first and second grooves  35 ,  36  for better grip. 
     In  FIG. 4 , a second embodiment of the disclosure is shown. An annular, second type, single lip, seal ring  40 , having an annular, first type fastening portion  41 , is attached in the recess  30  at the connection between the radial carrier flange  29  and the belt face portion  28  with its first type fastening portion  41 . The first fastening portion  41  can be press fit into the recess  30 , but other fastening methods can also be used, e.g., glue. The first type fastening portion  41  has an annular, axially extending third type sealing lip  42 , which is designed to radially meet and slidingly seal against the TVD secondary mass  14  in the cavity  30   a . As with the first example discussed above, the second type seal ring  40  is designed so that the third type sealing lip  42  is biased against the TVD secondary mass  14 , when mounted in place. The third type sealing lip  42  is funnel shaped to simplify assembly, but this is not a must. Reasons for not having it could be e.g., manufacturing reasons. 
     In a third embodiment, shown in  FIG. 5 , an annular, third type, seal ring  50 , having an annular, first type fastening portion  41  equal to the fastening portion of the second embodiment, is attached in the same way as in the second embodiment in the recess  30  at the connection between the radial carrier flange  29  and the belt face portion  28  with its first fastening portion  41 . The first fastening portion  41  can be press fit into the recess  30 , but other fastening methods can also be used, e.g., glue. The first fastening portion  41  in this embodiment has an annular, radially extending single fourth type sealing lip  51 , which is designed to axially meet and slidingly seal against the TVD, or, to be more exact, against an end surface  43  of the second mass carrier portion  15  of the TVD  13 , the second mass carrier portion  15  of the TVD  13  and its end surface  43  being located on the radially located inside of the annular, resilient ring  16  and inside the cavity  30 . As with the first example discussed above, the third type seal ring  50  is designed so that the fourth type sealing lip  51  is biased against the TVD second mass carrier portion  15 , when the third type seal  50  is mounted in place. 
     In  FIG. 6 , a fourth embodiment of the disclosure is shown, being a combination of the second and third embodiments. An annular, fourth type sealing ring  60  having an annular, first fastening portion  41 , equal to the one used in the second and third embodiment of the disclosure, is attached in the recess  30  at the connection between the radial carrier flange  29  and the belt face portion  28  with its first fastening portion  41 . Of course also here the fastening portion  41  can be press fit into the recess  30 , but other fastening methods can also be used, e.g., glue. The fastening portion  41  also here, like in the second embodiment of the disclosure, has an equally, axially extending third sealing lip  42 , which radially meets and slidingly seals against the TVD secondary mass  14 . In addition, like in the third embodiment, this fourth embodiment shows a fourth type sealing lip  51 , radially extending from the fastening portion  41 . The fourth type sealing lip  51  is designed to be biased to meet and slidingly seal against the TVD, or, to be more exact, against the end surface  43  of the second mass carrier portion  15  of the TVD  13 , the end surface  43  being located on the inside of the annular, resilient ring  16  and in the cavity  30 . The third sealing lip  42  is, as it is equal to the one in the second embodiment, funnel shaped to simplify assembly. 
     A fifth embodiment of the disclosure is shown in  FIG. 7 . An annular, fifth type sealing ring  70 , having an annular, second type fastening portion  71 , is attached to the second mass carrier portion  15  of the TVD hub  13  at the second mass carrier portion inner end  15   a , radially located at the end inside. The second type fastening portion  71  can be designed to be press fit, but it can alternatively be attached in other ways, e.g., glued. Extending radially outwardly from the second fastening portion  71  the fifth type sealing ring  70  has an annular, fifth type sealing lip  72 , which is designed to be biased and slidingly sealing against the axially inner surface  29   a  of the radial carrier flange  29 . 
     The invention concerned here is not limited to the examples shown on the drawings and described above but is defined by the accompanying claims. Thus the details of the TVD and the decoupling belt pulley per se can be different, as long as the invention related parts are not concerned. Since the different embodiments of the seal rings and their sealing lips are all annular, all the different parts of the assembly that are engaged by the sealing lips are also per definition annularly continuous. The seal rings can be made from any suitable resilient material, including plastic or rubber. Further, the seal ring could for instance be made from foam or a solid that could for example be sprayed onto the assembly, e.g., a rubber material. 
     While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention. Additionally, the features of various implementing embodiments may be combined to form further embodiments of the invention.