Internal-combustion engines – Poppet valve operating mechanism – Rocker
Patent
1997-11-18
1999-04-20
Lo, Weilun
Internal-combustion engines
Poppet valve operating mechanism
Rocker
123 9046, 123 9036, F01L 124
Patent
active
058948228
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OR THE INVENTION
The invention concerns a support element for a finger lever of a valve drive of an internal combustion engine comprising a hollow cylindrical housing arranged in a reception bore of a cylinder head, a slidable inner element arranged within the housing being supported by a compression spring on the housing, while one end of the housing cooperates with the cylinder head, and one end of the inner element cooperates with the finger lever.
A support element of the pre-cited type is known from EP 03 32 359 B1. The housing of the support element is retained in the bore of the cylinder by a ring. A drawback of this construction is that an additional groove has to be made in the housing and mounting is rendered more difficult because of the additional locking ring required. Besides this, this method of fixing does not secure the housing against rotation in the reception bore.
It is also known in this connection to retain the housing of the support element in the reception bore by groove and spring retention means.
However, a drawback of such methods is the difficulty of manufacturing and the problematic assembly. It is further known to fix the housing on the outer diameter with the help of a screw thread. In this case, besides the expensive manufacturing, there exists the danger of a binding of the slidable inner element if the tightening torque of the hollow cylindrical housing is too high. Finally, it is also possible to fix the housing in the reception bore of the cylinder head by a press fit. This, however, requires very precise matching of sizes and there is the danger of clamping of the inner element in the housing. In addition, this type of fixing does not permit dismounting.
SUMMARY OF THE INVENTION
It is therefore the object of the invention to provide a fixing of the housing in the cylinder head which enables a mounting and dismounting of the support element in a simple manner while avoiding the hitherto experienced drawbacks, and to provide simple means to prevent rotation of the housing.
The invention achieves this object in that the outer peripheral surface of the housing comprises a serration toothing which is pressed into the reception bore during mounting, or that the housing is connected positively to a bushing whose outer peripheral surface comprises a serration toothing which is pressed into the reception bore during muonting.
In this way, when the housing is pressed into the reception bore of the cylinder head, material is sheared off the tooth tips and displaced wholly or partly into the gaps between the teeth towards the root of the toothing so that a strong retention of the housing is obtained which, at the same time, results in a good prevention of rotation of the housing. This high security against rotation is particularly important when support elements have to be mounted in an inclined or horizontal position in the cylinder head because, in this case, the radial bore for hydraulic medium supply must be located in the gravity-remote region, i.e. at the highest possible geodetic point of the entire arrangement to prevent an emptying of the central reservoir with the known adverse effects. The fixing of the housing in the reception bore of the cylinder head according to the invention assures by the displacement of material of the serration toothing, on the one hand, that a binding of the slidable inner element is prevented and on the other hand, that the reception bore to be made in the cylinder head can have a simple configuration. The serration toothing can be made unproblematically, for example by knurling, or directly during the extrusion of the housing. The arrangement of the support element according to FIGS. 5 and 6 of the invention has the further advantage of the invention has the further advantage that the support element can be easily dismounted because the housing is only positively connected to the bushing.
Further developments of the invention are the subject matter of the subclaims and will be described more closely in the following. According t
REFERENCES:
patent: 4004558 (1977-01-01), Scheibe
patent: 4807576 (1989-02-01), Sonoda et al.
patent: 5311845 (1994-05-01), Takahashi
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