A SEALING ARRANGEMENT FOR A ROTATABLE SHAFT OF A COMBUSTION ENGINE

Abstract

The present invention relates to a sealing arrangement for a rotatable shaft of a combustion engine. The rotatable shaft comprises a crankshaft journal, a crankshaft gear and a flywheel. The sealing arrangement comprises a sealing member configured to be arranged in an annular space between a surface defining an opening for said rotatable shaft through a stationary wall of the combustion engine and an outer periphery surface of the rotatable shaft. The sealing member comprises a radially outer portion to be fixedly arranged to the surface defining said opening. The crankshaft gear comprises a portion provided with a smooth outer periphery surface and that the sealing member comprises a radially inner portion comprising at least one sealing lip configured to sealingly abut against the outer periphery surface of the crankshaft gear.

Claims

1. A sealing arrangement for a rotatable shaft of a combustion engine, wherein the rotatable shaft comprises a crankshaft journal, a crankshaft gear and a flywheel, wherein the sealing arrangement comprises a sealing member configured to be arranged in an annular space between a surface defining an opening for said rotatable shaft through a stationary wall of the combustion engine and an outer periphery surface of the rotatable shaft, wherein the sealing member comprises a radially outer portion to be fixedly arranged to the surface defining said opening, and wherein the crankshaft gear comprises a portion provided with a smooth outer periphery surface and that the sealing member comprises a radially inner portion comprising at least one sealing lip configured to sealingly abut against the outer periphery surface of the crankshaft gear.

2. A sealing arrangement according to claim 1, wherein the sealing lip is configured to abut against an outer periphery surface of the crankshaft gear with a resilient force.

3. A sealing arrangement according to claim 1, wherein the crankshaft gear is manufactured by a hardened steel material.

4. A sealing arrangement according to claim 1, wherein said outer periphery surface is arranged at an axial distance from a toothed portion of the crankshaft gear.

5. A sealing arrangement according to claim 1, wherein the flywheel comprises a surface which at least partly covers the annular space at one side of the sealing member.

6. A sealing arrangement according to claim 1, wherein the sealing member comprises an outer sealing ring designed to be fixedly attached to the surface defining said opening.

7. A sealing arrangement according to claim 6, wherein the outer sealing ring comprises a metal ring provided with a contact surface of a sealing material.

8. A sealing arrangement according to claim 1, wherein the stationary wall is a part of a flywheel housing.

9. A sealing arrangement according to claim 1, wherein the flywheel is a cast component manufactured of cast iron.

10. A sealing arrangement according to claim 1, wherein the crankshaft journal, the crankshaft gear and the flywheel are connected to each other by common bolts.

11. A sealing arrangement according to claim 1, wherein the flywheel comprises a guide portion to be arranged in a radial gap between a radial outer surface defined by the crankshaft gear an inner radial surface defined by the crankshaft journal.

12. A combustion engine comprising: a rotatable shaft of a combustion engine, wherein the rotatable shaft comprises a crankshaft journal, a fly wheel, and a crankshaft gear, wherein the crankshaft gear comprises a portion provided with a smooth outer periphery surface; and a sealing arrangement comprising a sealing member configured to be arranged in an annular space between a surface defining an opening for said rotatable shaft through a stationary wall of the combustion engine and an outer periphery surface of the rotatable shaft, wherein the sealing member comprises a radially outer portion to be fixedly arranged to the surface defining said opening, and wherein the sealing member comprises a radially inner portion comprising at least one sealing lip configured to sealingly abut against the outer periphery surface of the crankshaft gear.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] A preferred embodiment of the invention is described below by way of an example with reference to the attached drawings, on which:

[0015] FIG. 1 shows a sealing arrangement for a rotatable shaft of a combustion engine and

[0016] FIG. 2 shows the sealing arrangement in FIG. 1 more in detail.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION

[0017] FIG. 1 shows a cross sectional view of a part of a rotatable shaft of a combustion engine 1. This part of the shaft comprises a crankshaft journal 2, a crankshaft gear 3 and a flywheel 4. The crankshaft journal 2 constitutes an outer end of a crankshaft. The crankshaft gear 3 comprises a toothed portion 3a to be in engagement with a not visible gear wheel in the combustion engine. In this case, the crankshaft gear 3 comprises a portion with a periphery surface 3b arranged at an axial distance from the toothed portion 3a. The crankshaft gear 3 is manufactured by a hardened steel material. The flywheel 4 is arranged on the outside of the combustion engine 1. The flywheel 4 is manufactured of cast iron. The flywheel 4 comprises an annular guide portion 4a configured to be arranged in an annular gap defined by a surface 3c of the crankshaft gear 3 and a surface 2a defined by the crankshaft journal 2.

[0018] The flywheel 4 is rotatably arranged by means of a bearing 5. The crankshaft journal 2, the crankshaft gear 3 and the flywheel 4 comprises bolt holes such they in an assembled state are connected to each other by means of common bolts 6. A flywheel housing 7 comprises a wall section limiting an inner space of the combustion engine 1. The wall section of the flywheel housing 7 comprises an opening defined by a circular edge surface 7a. The rotatable shaft extends through the opening in the flywheel housing 7. A sealing member 8 is arranged in an annular space formed between the edge surface 7a defining said opening and the periphery surface 3b of the crankshaft gear 3. The object of the sealing member 8 is to prevent leakage of oil from the combustion engine 1 to the surrounding via said annular space and to prevent ingress of impurities from the surrounding to the inner space of the combustion engine 1. The flywheel 4 comprises a surface 4b covering the annular space on an outside of the sealing member 8.

[0019] FIG. 2 shows the sealing member more in detail. The sealing member 8 comprises an outer sealing ring in the form of a metal ring 8b provided with a sealing material 8c. The sealing ring is designed such that it has a somewhat larger diameter in a non-assembled state than the opening defined by the edge surface 7a. Thus, the sealing member has to be pressed into the opening to a mounting position. In the assembled state, the outer sealing ring acts with a pressing force on the edge surface 7a such that the sealing member 8 will be fixedly arranged in the opening. The existence of the sealing material 8c ensures that no leakage will arise between the outer surface of the outer sealing ring and the edge surface 7a of the flywheel housing 7. The sealing member 8 comprises an inner sealing portion in the form of a sealing lip 8a. The sealing lip has elastic properties such that it in a bent state abuts against the outer periphery surface 3b of the crankshaft gear 3 with a resilient force. Since the crankshaft gear 3 is manufactured of a hardened steel material, it has a very smooth outer periphery surface 3b. Due to this fact, it is possible to provide a very tight sealing between the sealing lip 8a and the rotatable outer periphery surface 3b of the crankshaft gear 3.

[0020] Before the sealing member 8 is assembled, it is possible to assemble the crankshaft gear 3 in contact with associated gear wheels in the combustion engine 1 and attach the crankshaft housing 7 in an intended position. After that, the sealing member 8 is pressed into the annular space between the edge surface 7a of flywheel housing 7 and the outer periphery surface 3b of the crankshaft gear 3. In an assembled state, the outer sealing ring 8b, 8c acts with a radially outwardly pressing force on the edge surface 7a of the flywheel housing 7 such that the sealing member 8 is fixedly arranged in said annular space. Furthermore, the sealing lip 8a abuts with a resilient force against the outer periphery surface 3b of the crankshaft gear 3 in a bent state. There is nothing obstructing the view of the annular space during the assembly process of the sealing member 8, which facilitates the assembly process. Furthermore, it is easy to check if the sealing member 8 has been assembled in a correct manner in the annular space. After that, the flywheel 4 is to be assembled. The guide portion 4a of the flywheel 4 is moved into the annular gap formed by the surface 3b of the crankshaft gear 3 and the surface 2a of the crankshaft journal 2. Thus, the assembly process of the sealing member 8 and the flywheel 7 is performed in sequence in two separate steps. Consequently, it is simple to assemble the sealing member 8 and associated components 3, 4, 7.

[0021] The invention is in no way limited to the embodiment to which the drawing refers but may be varied freely within the scopes of the claims.