The invention relates to a connection device for the pivotable and captive connection of a control lever and a support element of a mechanical valve controller of an internal combustion engine.
From U.S. Pat. No. 5,775,280, a connection device is known, wherein a control lever and a support element associated with the connection device are connected via a retaining element in a pivotable and captive manner. This connection device is especially advantageous because it avoids assembly problems in the manufacture of a mechanical valve controller of an internal combustion engine.
The retaining element known from this publication is designed as a sheet metal bracket, wire retaining clamp or plastic retaining cap, which engages into, among other things, an undercut in the support element below the spherical end of said support element. In the version of the sheet metal retaining bracket, to be explained in more detail in the following, this retaining element possesses an essentially U-shaped cross-sectional geometry and comprises two legs that are connected to each other via a connecting section. The first closed-surfaced leg is attached to the cam follower above a receiving calotte, while the second bifurcated leg engages into the undercut of the support element projecting into the calotte. Furthermore, both legs exhibit, on their free ends, retaining collars with which the retaining element may be clamped onto the cam follower as well as the support element in a captive manner.
Although this known connection device has a number of advantages, the fact that various adapted retaining elements are needed for different cam follower geometries still has to be considered as disadvantageous.
U.S. Pat. No. 6,047,675 and U.S. Pat. No. 6,543,402, respectively, also disclose other valve controllers for an internal combustion engine with these valve controllers also using wire-shaped retaining elements or retaining elements designed as sheet metal parts for the purpose of connecting the cam follower and the support element. The sheet metal retaining clamp is U-shaped in this case as well, with the two parallel running sheet metal legs being connected to each other via a connecting section.
Furthermore, contrary to U.S. Pat. No. 5,775,280, the two legs exhibit circular or U-shaped receiving openings in the area of their free ends. While the lower leg of this retaining element engages at the support element, the upper leg envelops, with its receiving opening, a portion of the spherical top side of that receiving calotte in which the also spherically shaped top side of the support element is supported in terms of a ball bearing.
Of special significance for the sheet metal retaining clamp, with the geometrically closed openings in the legs, is the fact that respective protrusions project into these receiving openings. The protrusions rest with a friction fit against the undercut-less cylindrical portion of the support element and holding it in a gripper-like manner, or being pressed onto the spherical top side of the support element.
A disadvantage of this type of connection device is that the support element is held only in a gripper-like manner and by friction fit by the sheet metal retaining clamp. Since there is no provision made for an engagement into an undercut (which does not exist in this case) of the support element, it has to be anticipated that the cam follower and the support element will fall apart in the event of heavy mechanical stress.
Against this background, various embodiments of the invention are based on the technical problem of creating a connection device for a connection between a cam follower and a support element, with said connection device being suited for different cam follower geometries in the connection area with the support element. Furthermore, various embodiments of this connection device are configured to ensure a secure, articulated, and captive connection between the cam follower and the support element even in the event of heavy mechanical stresses. And, finally, the retaining element of one embodiment of the connection device, which implements the mechanical connection between these two components, is configured to exhibit a low tendency to get stuck when stored with other retaining elements in a container, to be capable of being automatically mounted, and to be capable of being manufactured at low cost.
Although various embodiments of the invention are illustrated and described herein as embodied in a connection device and/or joining device, it is, nevertheless, not intended to be limited to the details shown because various modifications and structural changes may be made therein without departing from the spirit of various embodiments of the invention and remain within the scope and range of equivalents of the claims.
Accordingly, various embodiments of the invention relate to a connection device for the pivotable and captive connection of a control lever and an associated support element of a valve controller of an internal combustion engine. The control lever exhibits, in one supporting section, a calotte-shaped recess in which the spherical end of the support element is located. In the support element of the connection device, a notched recess or an undercut is located below a spherical end of the support element. In the control lever of the connection device, a supporting section above the calotte-shaped recess exhibits a spherical geometry. A retaining element of the connection device connects the control lever and the support element.
In accordance with a feature of one embodiment of the invention, the retaining element exhibits a U-shaped cross-sectional geometry with an upper and a lower leg being connected via a connecting section. There are also geometrically closed openings provided in the legs for the purpose of receiving the undercut of the support element or the spherical top side of the supporting section of the control lever, with the opening in the upper leg being essentially round and the opening in the lower leg being essentially slot-shaped.
In various embodiments of the invention the control lever is designed as a cam follower and the support element as an axially movable piston.
With respect to the retaining element, one embodiment considers having material thickness to be less than the width of the undercut to be advantageous so that the retaining element is freely movable in all pivot positions of the control lever in the undercut.
According to another embodiment of the retaining element, the legs and, specifically, the connecting section of the retaining element are smooth-surfaced, reducing the tendency toward jamming of such a retaining element in an assembly supply container and allowing easy placement onto the control lever and the support element. It is specifically the closed surface of the connecting section that allows this component part to be grasped with an automatic assembly vacuum gripper.
In particular, the placement of the retaining element onto the control lever between its side walls is facilitated if the legs of the retaining element exhibit lead-in chamfers in the area of their free ends, virtually sharpening these legs.
Another facilitation of assembly in putting together the control lever and the support element can be achieved in further developments of one embodiment of the invention by designing the free ends of the legs such that they point away from each other.
In the further development of one embodiment of the invention, the positioning of the retaining element on the support element is also benefited by the slot-shaped opening in the lower leg exhibiting a stadium-like geometry with two opening sections running parallel to each other and being connected by semi-circular opening sections.
The expansion of this opening in the lower leg, which is used for the placement of the retaining element onto the support element, is further facilitated if a slot-type extension of the opening with a preferably small opening width is provided in at least one of the above-mentioned semi-circular opening sections. This makes it easier for the sections of the lower leg to twist against each other during the axial placement onto the support element, causing the cross section of the opening to be briefly expanded. Following the above-mentioned placement, the originally smooth surface of the lower leg is reconverted so that this leg then engages into the undercut of the support element in a captive manner.
Furthermore, the opening in the upper leg of the retaining element is designed such that this leg is securely fastened on the spherical, e.g. ball-shaped head-type, top side of the supporting section of the control lever.
In accordance with another further development of one embodiment of the invention, it is provided that the width of the opening in the lower leg is smaller across its longitudinal extension than the diameter of the opening of the upper leg. The effect of this combination is that, given a preset undercut depth, sufficient retention is ensured on the spherical top side of the control lever, or that, given a preset diameter of the opening in the upper leg, a sufficiently large undercut depth is utilizable. To ensure a secure retention, it is essential that the width of the opening in the lower leg at a right angle relative to its longitudinal extension is smaller than the diameter of the support element above and below the undercut.
Furthermore, the design of this retaining element can also be such that the upper leg is axially shorter than the lower leg. This advantageously achieves a reduction of weight and costs as compared to legs of equal length, while the secure retention on the spherical top side of the supporting section of the control lever is ensured even when the retention element does not precisely envelop, with the opening of its top legs, the pole area of the spherical top side of the supporting section.
Another aspect concerns the distance of the two legs of the retaining element. Preferably, it is provided that the connecting radius between the lower leg and the connecting section is smaller than the connecting radius between the latter and the upper leg. This causes the retaining element to seat itself in the assembled state, i.e. slightly bent open, with its connecting section closely against the front side of the control lever as well as against the spherical top side of the supporting section.
And finally, various embodiments of the invention provide for the distance between the lower leg and the upper leg of the retaining element to be greater in the vicinity of the connecting section than in the area of the free end of the two legs. This has the effect that, given selection of a suitable preferably sheet metal material for the retaining element, the control lever and the support lever are held together in the assembled state by an increased elastic retention force.
The present invention will be described by way of exemplary embodiments, but not limitations, illustrated in the accompanying drawings in which like references denote similar elements, and in which:
FIGS. 1 to 3 show a control lever, designed as a cam follower 1, of a mechanical valve controller of an internal combustion engine which is, in essence, known and which was described above. This cam follower 1 may pivot around an axis of rotation 2 and it exhibits a supporting section 3, in which a spherical top side 4 of a calotte-shaped recess 5 is provided between two wall sections of the cam follower 1.
As can be gathered, in particular, from the cross section A-A through the cam follower 1 in
The support element 6 exhibits a spherically shaped top side 7 which fits precisely into the calotte-shaped recess 5 of the cam follower 1. Below this top side 7, there is an undercut 8 in the support element 6 with said undercut serving to receive the retaining element 9 shown in
This retaining element 9 is designed, in this case, as a sheet metal component and is provided with an upper leg 10 as well as a lower leg 11 which are connected to each other via a connecting section 12.
As illustrated by the perspective view of the retaining element 9 in accordance with
What is important is that the opening in the upper leg 10 is essentially circular and the opening in the lower leg 11 is essentially slot-shaped. It is also revealed that the material ridges on both sides of the elongated opening in the lower leg 11 engage into the undercut 8 of the support element 6, while the circular opening in the upper leg 10 is supported by the spherical top side 4 of the cam follower 1.
As shown especially in
As can be gathered especially from
In contrast, opening 14 in the lower leg 11 is essentially slot-shaped and has, in the embodiment presented here, a stadium-like design with two essentially parallel opening sections being connected via two semi-circular opening sections. As shown in
It is also revealed that there are lead-in chamfers 17, 18, 19, 20 provided on the free ends 15, 16 of the two legs 10, 11, allowing easy insertion of the retaining element 9 between the side walls of cam follower 1 with these side walls being particularly readily identifiable in
As shown in
And finally, FIGS. 5 to 7 show that the upper leg 10 is axially shorter than the lower leg 11. This has the advantageous effect of a weight and cost reduction as compared to legs of equal length, while the secure retention on the spherical top side 4 of the supporting section 3 of the cam follower 6 is ensured even if the retaining element 9 does not precisely envelop, with the opening 13 of its upper leg 10, the pole area of the spherical top side 4 of the supporting section 3 or if it does not have an approximated spherical shape.
Furthermore, the slightly longer design of the lower leg 11 makes possible a comparatively long slot-shaped opening 14 promoting the centering of the retaining element 6 and the cam follower 1.
Number | Date | Country | Kind |
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10 2004 005 831.8 | Feb 2004 | DE | national |
The present application claims priority under 35 U.S.C. §120 to International Patent Application No. PCT/DE2005/000153, filed Feb. 1, 2005, entitled “Joining Device for an Actuating Lever and a Supporting Element of a Valve Operating Mechanism of an Internal Combustion Engine” and International Priority under 35 U.S.C. § 119 to co-pending German Patent Application No. 10 2994 005 831.8, filed Feb. 6, 2004, entitled “Verbindungsvorrichtung fuir einen Betätigungshebel und ein abstützelement einer ventilsteuerung einer brennkraftmaschine”; the entire contents and disclosures of which are hereby incorporated by reference in its entirety.
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/DE05/00153 | 2/1/2005 | WO | 9/25/2006 |