DE29924858U1 - Valve train assembly, comprises a valve rocker arm in connection with cam shaft assembly of the engine via a tappet assembly - Google Patents

Abstract

The rocker arm (B) is centre pivoted an mounted on a tappet (4). The tappet is positioned between a roller (R) that is displaces and pushed against a cam (C), and a poppet valve (V) against the valve spring (M). The tappet comprises a rounded engagement head (41) that co-operates with a circular recess on the rocker arm.

Description

The The present invention relates to a valve train assembly for one Internal combustion engine and on rocker arm for such an arrangement. The This invention is particularly, but not exclusively, to Arrangements in which the number of parts in the assembly is reduced where different parts can be preassembled to To facilitate the engine mounting, and making different parts easier be made.

Various Aspects of the invention are intended to be with a number of separate To deal with problems with existing arrangements. For example, they tend Internal combustion engines, which have a variety of valves for each Cylinders have to use rocker arms on a common Fulcrum or a common axis are mounted, and therefore have different lengths have to, to match the different positions of the valves. It is therefore necessary to produce two different types of rocker arms.

It is also common especially for suspended in the middle Rocker arm, that one has a hydraulic play compensation device has, which are mounted on the valve end of the rocker arm, and continue is common, that device for that is continuously moved back and forth. This requires a complex processed oil distribution path and makes it harder, oil to guide to the lash adjuster. Furthermore, the components the rocker arm heavy, and therefore are strong valve return springs required, and the rocker arm must be tight, and therefore one huge Diameter and must be heat treated be to the surface to harden, to withstand the wear.

Various Aspects of the present invention are set forth in the appended claims.

In a preferred embodiment a valve train assembly for an internal combustion engine a valvetrain with a variety of individual toggle fulcrums, and a rocker arm, the on attached to each fulcrum. The wearer may also have one or more have it mounted camshafts.

A such arrangement may be a preassembled unit for installation in a cylinder head with valves mounted on it, causing the assembly an engine easier.

Everyone Fulcrum may be part of a hydraulic lash adjuster be. Since the Spieleinstellvorrichtungen firmly mounted on the carrier would They become easier with oil supplied, leaving a smaller oil pump can be used, which generates a relatively low pressure.

In a particularly advantageous arrangement, each rocker arm and his belongings Fulcrum co-operating partially spherical surfaces, the not only allow the pivoting movement required for the operation of the valves is, but also a degree of rotation around the length of the Rocker arms to provide a self-adjusting function. Especially the rocker arm has a partial spherical recess in the one partially spherical Projection is arranged. (In practice, the profile of the recess several, for example three, spherical segments of slightly different Diameter tangent to each other, which are also referred to as "Gothic base" or "Gothic version" can.) The rocker arm can be attached to the projection by means of a clip that may be made of spring steel, which is placed on the head of the projection is. When the rocker arms are not placed on the rocker axles have to, can they are made smaller and lighter compared to existing ones Rocker arms made of aluminum or steel. In a preferred embodiment The rocker arms are made of pressed sheet metal (where the final thickness possibly enlarged by the pressing process or is reduced to appropriate properties in terms of weight and strength their ease is the application of lighter ones Valve springs allows which results in lower energy consumption.

Because of the above mentioned Self-adjusting arrangement makes it possible to have a contact between to arrange a drive cam and the rocker arm, so that he himself laterally over a big Distance extends, for example, on the rocker arm a Roller mounted with a wide surface, which is flat in a direction parallel to the roller axis. This creates a larger contact area than existing ones Rocker arms that rotate around an axis, and a roll with a convex surface need to have, for a proper contact sure. As a consequence of the reduction of stress by Magnification of the contact area The camshaft does not have to be so strong or strong and it is actually possible to cast iron instead of using more expensive steel.

By appropriate positioning of each rocker fulcrum is it is possible Rocker arms of the same length for all To use valves. Accordingly, the rocker arms can be substantially identical be, which reduces the manufacturing cost.

Arrangements embodying the invention will now be described by way of example with reference to FIGS attached drawings in which the figures represent the following:

1 a side view of a rocker arm of the prior art;

2 a side view, partially in section, of a rocker arm assembly according to the invention, which is applied to a valve;

3 a side view of the rocker arm of 2 ;

4 a view of the rocker arm in 3 is shown;

5 a section along the line VV the 3 ;

6 shows a section along the line VI-VI in 3 ;

7 is a section through a hydraulic driver, which forms a pivot point of the rocker arm;

8th Fig. 12 is a cross-sectional view showing a valvetrain carrier of the present invention for controlling two rows of valves with a single center camshaft;

9 is a view of the valvetrain carrier as in FIG 7 shown;

10 is a side view showing another embodiment of a valve train assembly according to the invention; and

11 is a perspective view from below of a valve gear carrier of the arrangement of 10 ,

1 shows a rocker arm B 'of the prior art, which is made of pressed aluminum, and which has a lever of the first order, on a fixed axis 70 is mounted, which also carries other rocker arms, which are arranged in a row. One end of the rocker arm B 'is in contact with a cam C by means of a roller R', while the other end has a reciprocating and pivoting hydraulic lash adjuster which also acts as a dog 80 referred to as. The driver has a stand or projection 81 at the base acting on the head of a valve V. A double row of camshafts A 'acts on convex surfaces of the rollers R'.

2 shows an example of a rocker arm assembly according to the present invention.

The rocker arm B of the present invention, in turn, is a first-order lever, ie, it is a rocker arm pivoted in the center. However, the rocker arm B is on a driver 4 mounted, which is arranged between a first end of the rocker arm B, which is mounted on a roller R, which is pushed and pushed against a cam C on the camshaft, and a second end, which transmits the pressure to the seat valve V against to open the elastic force of a spring M.

The rocker arm B, which in the 3 to 6 is shown, consists of two lateral flanges 12 and 12 ' passing through a top plate 13 are connected, with which this forms a U-shaped cross-section, and is formed by bending or punching a steel sheet.

In the process of pressing the rocker arm from a steel sheet becomes a hemispherical recess 14 in the plate 13 shaped, which is suitable to with a hemispherical head 41 a stand or projection 42 to fit together, the part of a Spieleinstellvorrichtung or a driver 4 is. The driver 4 is on his own tight seat 45 ( 7 ) formed by drilling an aluminum cover L of the engine head. The cover L forms a valvetrain carrier and will be discussed below.

Because of the cooperation of the partially spherical surfaces of the recess 14 and the end 41 of the stand 42 this stand forms a fulcrum around which the rocker arm B can move back and forth to actuate the valve V and around which the rocker arm can be turned laterally. It is noted in particular that the rocker arm about an axis X ( 4 ) and around the axis of the stand 42 to provide a degree of self-adjustment, for purposes set forth below.

The rocker arm B has a transverse opening at one end 15 on, in which a pivot pin 16 is fitted, with the pin 16 opposite recesses 17 one of which presses on the head of the stem of the valve V, which adjusts itself according to the relative movement of the rocker arm B of the valve stem, which may vary depending on the type of engine.

At the other end is the fitted roll R, which has needle bearings and on an axis 20 is located, passing through the openings 22 that extends in the flanges 12 and 12 ' are provided.

The roller R is very simple, with a straight cylindrical outer surface, which fits tightly to the outer surface of the cam C, as described above wrote, the rocker arm with its pivot point on the hemispherical recess 14 , automatically compensates for imperfect transverse movements, thus rendering a convex outer surface unnecessary, as required by the conventional design.

To the pin 16 Locally holding at the first end of the rocker arm, is an elastic sheet 25 with flanges 26 used, which are bent back on itself, so that the lower section can be attached to the rocker flanges (see 5 ). The elastic sheet has an inlet 27 at the upper part for the purpose of lubrication of the pin 16 ,

A second elastic sheet 30 with flanges 31 , which are bent back on themselves, is about the hemispherical recess 14 fitted to a relative transverse movement of the stand 42 of the driver 4 limit. The sheet 30 can be made of spring steel and has an opening that allows the rocker arm B slightly above the head 41 of the stand 42 snaps fit and thus attached to the cover L. The sheet 30 thus keeps the rocker arm B on the cover L without any intentional operational movement of the rocker arm restrict.

In this embodiment, the projection or the stand 42 a relatively narrow neck, resulting in an enlarged partial spherical head 41 leads, leaving the opening in the sheet 30 , which has a slightly larger diameter than that of the neck, can be used to hold the rocker arm locally. Preferably, as in 4 shown, the opening is elongated, wherein the longitudinal axis extends substantially parallel to the length of the rocker arm to a fitting of the rocker arm on the driver 4 to facilitate and to allow a degree of freedom of movement in the longitudinal direction to ensure proper engagement with the camshaft and the valve. However, alternative arrangements are possible. For example, the rocker arm on the head 41 be secured by means of a rivet or other element which extends through the rocker arm in a recess at the end of the head 41 extends, possibly engaged therein by means of a screw thread or by means of a resilient enlarged part, which engages with an annular edge within the recess. In any event, it is desirable that the means which attach the rocker arm to the fulcrum be rather loose and arranged so as not to restrict the intended operational movement of the rocker arm.

7 is a detailed view of the driver 4 holding the rocker arm B pressed against one end of the valve head V, by means of the pivot pin 16 , and at the other end against the cam C by means of the roller R. The stand 42 who has the hemispherical head 41 which forms the rocker arm fulcrum, forms a plunger which bears against a chamber 43 attached in a sleeve 44 slides precisely into the seat 45 is introduced, formed by a hole in the cover L of the engine block. Inside the lower part of the chamber 43 there is a high-pressure driver chamber 47 while up a pestle 48 which is a low pressure oil reservoir 49 receives. The oil gets through the inlet 50 and the channels 51 directed into the cover L.

inlets 46 and 46 ' are in the stand 42 for the purpose of lubrication of the hemispherical end 41 provided, which acts as the fulcrum.

For example, show 8th and 9 from the side and from the top, the arrangement of a valve timing drive using rocker arms B1, B2, ..., as described above, for operating valves V1, V2, ... in an internal combustion engine with a single central camshaft A.

The use of such an arrangement facilitates the assembly of the engine. The engine cylinder head has a lower head part 65 , in which the valves V1 and V2 are installed. Their springs M are in recesses 60 of the lower head 65 located.

In a separate operation, the valvetrain carrier formed by the cover L has fitted thereon rocker arms B1 and B2 together with other rocker arms required for the engine (see 9 ). This therefore forms a self-supporting assembly which can be manufactured and sold separately from the remainder of the engine and ready to be delivered in a preassembled condition for fitting into the engine. Thus, not only the entire assembly is facilitated by the pre-assembly of the valve carrier, but the individual fitting of the rocker arms can be performed as a separate operation, so that the final assembly of the engine is considerably easier.

If desired, a manufacturer can provide different versions of the valve carrier, all for fitting in the same engine head, but with different equipment. For example, one version may have hydraulic lash adjusters and rocker arms provided with rollers, while another, less expensive version, rather than rollers, may include mechanical lash adjusters and a fixed cam-engaged surface on the rocker arms. This facilitates the production of different types of engines that are suitable for the customer while maintaining a simple assembly pro cedur allows.

The Location of the respective pivot points on the cover L can be so selected be that all rocker arms have the same length and therefore identical can be built if desired.

Preferably the camshaft is also fitted to the cover L during pre-assembly.

The 10 and 11 , in which like reference numerals represent like parts, show an alternative embodiment of the invention in which two camshafts A1, A2 drive respective rows of rocker arms B. The aluminum valve train carrier L is best in 11 which shows identical rocker arms B mounted in two rows, the arms being positioned within each row in a stepped arrangement so as to be suitable for driving the intake and exhaust valves. Although this in 11 is not shown, the camshafts A1, A2 are also preferably mounted on the carrier L, before the entire assembly is fitted to the lower cylinder head of the engine. The carriers L of each embodiment may have channels for distributing oil to the valve trains; in fact, all the necessary oil passages can be located in the carrier.

Claims (13)

Valve train assembly comprising: a valvetrain with a plurality of individual rocker fulcrums each of which Is part of a hydraulic lash adjuster; and a Variety of rocker arms, each rocker arm on a respective Fulcrum is attached and pivotable about the fulcrum; in which the arrangement is separate from an internal combustion engine, which is a camshaft having been produced and subsequently assembled, on the internal combustion engine but is operationally attachable, so that the rocker arms are movable by cams of the camshaft to valves to operate the engine. Valve train assembly comprising: a valvetrain with a variety of individual rocker fulcrums, each of which Is part of a hydraulic lash adjuster; and a Variety of rocker arms, each rocker arm by snap connection attached to a respective pivot point and around the pivot point is pivotable around, with the attachment is designed to rotating Pendulum movement to prevent a first axis not to valve operation or allow rotation about a second axis along the length of the rocker arm, to allow self-adjustment; the arrangement being separate from an internal combustion engine having a camshaft and subsequently has been assembled on the internal combustion engine but operationally attachable so that the rocker arms are movable by cams, to operate valves of the engine. Valve train assembly comprising: a valvetrain with a variety of individual rocker fulcrums, each of which Is part of a hydraulic lash adjuster; and a Variety of rocker arms, each rocker arm on a respective Pivot point is attached and pivotable about the pivot point, wherein each rocker arm is molded with a Gothic version, for Matching with a surface the pivot point to which it is attached; the arrangement separate from an internal combustion engine having a camshaft, produced and then has been assembled on the internal combustion engine but operationally attachable so that the rocker arms are movable by cams, to operate valves of the engine. Valve train assembly comprising: a valvetrain with a variety of individual rocker fulcrums, each of which Is part of a hydraulic lash adjuster; and a Variety of rocker arms, each rocker arm on a respective Fulcrum is attached and pivotable about the fulcrum; in which the rocker arms are substantially identical and in an array two rows are provided, with the rocker arms within each Row of positions are arranged successively and in places Are offset in opposite directions with respect to the row; in which the arrangement operationally attachable to an internal combustion engine is so that the rocker arms are movable by cams to valves to operate the engine. Arrangement according to one of the preceding claims, wherein each rocker arm having an elastic and apertured element is provided, for placing on the associated pivot point to the rocker arm to attach to the fulcrum. Arrangement according to one of the preceding claims, wherein each rocker arm carries a roll to Engaging a cam of a camshaft, and wherein each roller has a substantially flat cylindrical outer surface. A valve train assembly comprising: a valvetrain carrier having a plurality of individual rocker fulcrums, each of which is part of a hydraulic lash adjuster; a plurality of rocker arms, each rocker arm having a resilient, apertures Plate is provided, by means of which it is movably mounted at a respective pivot point which extends through the openings having sheet metal, wherein the rocker arm is pivotable about the pivot point; wherein each rocker arm further comprises a roller having a straight cylindrical outer surface for engagement with a cam. Arrangement according to one of claims 1, 3, 4 and 7, wherein each Rocker arm by snap connection at a respective pivot point is appropriate. Arrangement according to one of claims 1, 2, 4 and 7, wherein each Rocker arm has been formed by deformation of a sheet, wherein the deformation also forms a part-spherical surface to mate with a corresponding surface of the Fulcrum on which the rocker arm is mounted. Arrangement according to one of claims 1, 2, 3 and 7, wherein the Rocker arms are substantially identical. Arrangement according to one of the preceding claims, wherein the carrier having channels formed therein, for conducting oil to the fulcrum. Arrangement according to one of the preceding claims, wherein the carrier Rocker arm for Inlet and outlet valves for carries a variety of cylinders. Internal combustion engine with a valve drive arrangement according to any one of the preceding claims, wherein the motor is a plurality of cylinders, each of which has inlet and outlet valves, and wherein the carrier Rocker arm for carries the inlet and outlet valves.