This application is a National Stage application which claims the benefit of International Application No. PCT/EP2007/063455 filed Dec. 6, 2007, which claims priority based on German Patent Application No. 102006059716.8, filed Dec. 18, 2006, both of which are hereby incorporated by reference in their entirety.
The invention relates to an anti-rotationally secured tappet of a valve drive of an internal combustion engine according to the preamble of the claim 1 as well as to an anti-rotationally secured tappet according to the preamble of claim 1.
Document DE 196 00 852 A1 teaches of an anti-rotationally secured tappet of a valve drive of an internal combustion engine, preferably a bucket tappet composed of a base and a skirt, that is arranged between a cam and a valve and is guided in a receiving bore of a cylinder head. An anti-rotation component is arranged in a recess of the skirt, which anti-rotation component is guided in a guide groove of the cylinder head. The anti-rotation component is designed as an elastic spring element and consists of a back as well as two clips attached thereto, which clips are clipped into two longitudinal slits in the skirt of the tappet. It is disadvantageous that constructed space is greatly limited owing to the length of the clips on the interior of the tappet and, moreover, the two legs of both clips must have a high degree of spring preload in order to ensure a necessarily tight fit of the anti-rotation component so that with thin-walled skirts, in particular, an unacceptably high demand of the material of the skirt cannot be excluded.
Document DE 195 01 061 A1, for example, teaches of a further anti-rotationally secured tappet.
The invention is concerned with the object of providing for an anti-rotationally secured tappet of the generic type an improved embodiment in which an anti-rotation component can be designed in a constructively simple manner and can be simply and securely connected to the tappet with unnecessarily high stress peaks being placed on the material of the tappet.
According to the invention, this objective is solved by the subject matter of the independent claims. Advantageous embodiments of the invention are the subject matter of the dependent claims.
The invention is based on the general idea of providing in an anti-rotation component two spring arms that extend in the circumferential direction of a tappet, which spring arms guarantee for an anti-rotation component mounted on the tappet that said anti-rotation component is locked into position above the two spring arms. Both spring arms abut at least regionally either an external lateral surface of the tappet or an internal lateral surface of the skirt of the anti-rotationally secured tappet and lock the anti-rotation component into position on the tappet by means of a radial clamping craft that acts thereon. The skirt in this instance also comprises a transition region to a floor of the tappet. In so far as the two spring arms of the anti-rotation component abut the internal lateral surface, said spring arms have a greater radius than the interior lateral surface, which permits the spring arms to load by pushing radially outward against the interior lateral surface of the skirt of the tappet. In an anti-rotational securing with spring arms abutting the external lateral surface, said spring arms have a smaller radius than the exterior lateral surface, so that with an anti-rotation component locked into position on the tappet, they clampingly grip the tappet and press with a radially-inward directed force against the external lateral surface of the skirt/tappet. With the anti-rotation component according to the invention, owing to the circumferentially radially abutting spring arms, a high degree of clamping force can be transferred without having to accept regional surface pressure and concomitant material overstressing. Moreover, such an anti-rotation component can be manufactured as an inexpensive formed sheet metal part, thereby permitting a reduction in production costs in particular.
A radial annular groove that at least partially receives the spring arms of the anti-rotation component is advantageously arranged on the internal lateral surface of the skirt. Such an annular groove considerably simplifies the mounting of the anti-rotation component on the tappet and locks said anti-rotation component into position in an axial direction on the tappet when in an assembled state. Moreover, such a radial annular groove can be integrated without additional expenditures into an anti-rotation component of the tappet, which component is required in any case, in such a manner that no appreciable additional costs result. The annular groove furthermore makes a forced positioning of the anti-rotation component possible since said annular groove necessarily determines a predetermined and predefined position of the anti-rotation component in an assembled state. In an anti-rotation component with spring arms abutting the external lateral surface, a radially outwardly open annular groove is provided on the external lateral surface that completely receives the spring arms of the anti-rotation component in such a manner that said spring arms do not radially protrude beyond an external circumference of the external lateral surface at any location.
The invention is furthermore based on the general idea of providing the anti-rotation component as a lug-like insert element, that is to say without spring arms, the insert element being held in a form-fitting and/or force-fitting manner on the tappet in a radially outwardly open and radially inwardly closed groove. Such a design of the anti-rotation component simplifies the latter immensely, it being possible to achieve a force-fit between the anti-rotation component and the groove by means of soldering, cementing or welding, for example. This anti-rotation component is arranged in the floor region of a tappet having a floor and a skirt adjacent to said floor. A connection in the form of a dovetail is conceivable between the anti-rotation component and the corresponding groove, the anti-rotation component having a dovetail-like cross-section while the groove has an undercut cross-section corresponding thereto so that the anti-rotation component is form-fittingly held in the groove.
Advantageous exemplary embodiments are illustrated in the drawings and explained in greater detail below.
The figures show in schematic diagrams
a to c different illustrations of the anti-rotation component according to
a to d a sectional representation through an anti-rotation component and an anti-rotationally secured tappet according to
a a longitudinal cross section view through an anti-rotationally secured tappet according to
b an anti-rotation component as interior clip,
a, b an illustration as in
a to c a cross-section through an anti-rotationally secured tappet according to the invention in the region of the insert element.
Corresponding to
According to
a shows such an anti-rotation component 6 with its circumferentially extending spring arms 8, 8′ that meet in the region of a back 11 that protrudes radially outward. The anti-rotation component 6 can be designed as a formed sheet metal part, the two spring arms 8, 8′ in an anti-rotation component 6 according to
According to
a shows a cross-section through the anti-rotationally secured tappet 1 in the region of the annular groove 9, the radially inward recoiling axial groove 12 also being shown. The anti-rotation component 6 according to
The anti-rotation component 6 according to
The advantage of the anti-rotation component according to the invention lies in the fact that due to its design, an axial displacement of the anti-rotation component 6 as well as a displacement thereof owing to the annular groove 9 or the axial groove 12 is not possible. A high degree of retention force can also be achieved through the spring clamping force of both spring arms 8, 8′, which force acts radially circumferentially on a large surface, while because of the large surface, the surface pressure is relatively minimal so that no deformations of the tappet 1 are to be expected. Moreover, during the operation of the anti-rotation component 6, no unhinging of the anti-rotation component 6 is possible. Assembling the CRS 6 is very simple and is possible without the use of complex apparatuses and tools owing to its self-positioning in the annular groove 9 and the axial groove 12 as well as the spring loads of the two spring arms 8, 8′.
According to
According to
In contrast thereto, according to
According to the embodiment of the anti-rotation component 6 in
All of the features represented in the description and in the following claims can be pertinent to the invention individually and collectively in arbitrary combination.
Number | Date | Country | Kind |
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10 2006 059 716 | Dec 2006 | DE | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/EP2007/063455 | 12/6/2007 | WO | 00 | 12/7/2009 |
Publishing Document | Publishing Date | Country | Kind |
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WO2008/074651 | 6/26/2008 | WO | A |
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Number | Date | Country | |
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20100294219 A1 | Nov 2010 | US |