JP4558938B2 - Valve train assembly - Google Patents

Abstract

A valve train assembly for an internal combustion engine comprises a common carrier which supports the engine's rocker arms by means of individual fulcra each of which preferably forms a part of a hydraulic lash adjuster. Each rocker arm is constructed by deforming a metal sheet into a channel shape, the deformation also forming a part-spherical surface for mating with a surface of the fulcrum. The rocker arms can be snap-fitted on to the fulcra by means of an apertured, resilient sheet.

Description

[0001]
The present invention relates to a valve train assembly for an internal combustion engine and a rocker arm of such an assembly. In particular, but not exclusively, the present invention reduces the number of parts in the assembly, allows various parts to be pre-assembled to facilitate engine assembly, and makes the various parts even simpler. Concerning configuration.
[0002]
Various aspects of the present invention address a number of independent issues in existing configurations. For example, internal combustion engines with multiple valves in a cylinder tend to use rocker arms that are attached to a common pivot or axle and therefore need to have different lengths to fit different positions of the valves. . Therefore, it is necessary to manufacture two different types of rocker arms.
[0003]
In particular, with respect to the central pivot type rocker arm, a hydraulic lash compensator is generally reciprocated by attaching it to the valve end of the rocker arm. This requires a complicated supply path for machine oil, making it more difficult to supply oil to the lash adjuster. In addition, the rocker arm components are heavy and therefore require a strong valve return spring, and the rocker shaft must be strong because it must be strong, and it must be surface resistant to withstand wear. It must be heat treated to cure.
[0004]
Various aspects of the invention are set forth in the appended claims.
[0005]
In a preferred embodiment, a valve train assembly for an internal combustion engine includes a valve train support having a plurality of individual rocker arm fulcrums and a rocker arm attached to each fulcrum. The support may have one or more camshafts attached to it.
[0006]
Such a configuration can be provided as a pre-assembled unit that is mounted on a cylinder head with a valve mounted therein and thus substantially facilitates assembly of the engine.
[0007]
Each fulcrum may form part of a hydraulic lash adjuster. Thus, since the lash adjuster is fixedly attached to the support, the lash adjuster is more easily supplied with oil, so a smaller oil pump that produces a relatively low pressure can be used.
[0008]
In a particularly advantageous configuration, each rocker arm and its corresponding fulcrum allows not only the pivot movement necessary to actuate the valve, but also some rotation around the length of the rocker arm to provide a self-adjusting function And has a cooperating partial spherical surface. The rocker arm preferably has a partially spherical recess into which a partially spherical protrusion is fitted. (In practice, the shape of the recess may have several, e.g., three, spherical parts that are slightly different in diameter and touch each other, sometimes referred to as Gothic sockets.) It can also be attached to the protrusion by means of a clip that can be made of steel and fits on the head of the protrusion. The rocker arm need not be fitted to fit the rocker axle, and can be made smaller and lighter than existing aluminum or steel rockers. In a preferred embodiment, the rocker is made from a pressed metal plate (the final thickness can be increased or decreased by pressing to have the appropriate weight / strength characteristics) and, due to its light weight, more Light weight valve springs can be used, resulting in lower energy consumption.
[0009]
With the above-mentioned self-adjusting device, it is possible to contact the drive cam and the rocker arm laterally over a long distance, for example, by attaching a roller having a wide surface that is flat in a direction parallel to the roller axis to the rocker. is there. This provides a wider contact area than existing rockers that require a roller with a convex surface that rotates around the axle to ensure proper contact. Since the stress is reduced by increasing the contact area, the camshaft need not be as strong and cast iron can be used in place of the more expensive steel.
[0010]
By properly positioning the individual rocker arm fulcrums, equal length rockers can be used for all valves. Thus, the lockers can be made substantially the same, thereby reducing manufacturing costs.
[0011]
An apparatus embodying the present invention will now be described by way of example with reference to the accompanying drawings.
[0012]
FIG. 1 shows a prior art rocker having a primary lever attached to a fixed shaft (70) made of pressed aluminum and also supporting other rockers arranged in a row. B ′). One end of the rocker (B ′) is in contact with the cam (C) by a roller (R ′), and the other end is also called a tappet (80). Has a lash adjuster. The tappet has a spigot acting on the head of the valve (V), that is, a protrusion (81) at the bottom. Two rows of camshafts (A ′) act on the convex surface of the roller (R ′).
[0013]
FIG. 2 shows an example of a rocker arm configuration according to the present invention.
[0014]
The rocker (B) of the present invention is also a primary lever, that is, a central pivot rocker arm. However, the rocker (B) transmits pressure to the first end of the rocker (B) into which the roller (R) that is moved and pressed toward the cam (C) on the camshaft is fitted. The poppet valve (V) is mounted on a tappet (4) arranged between the second end which opens against the elasticity of the spring (M).
[0015]
The rocker (B) shown in FIGS. 3 to 6 is made up of two lateral flanges (12) and (12 ′) connected by an upper plate (13) and forming a U-shaped cross section with the upper plate (13). It is formed by bending or crushing a steel plate.
[0016]
In the process of pressing the locker from the steel plate, the lash adjuster, i.e. the hemisphere adapted to fit the spigot, i.e. the hemispherical head (41) of the protrusion (42), which is part of the tappet (4) A concave portion (14) is formed in the plate (13). The tappet (4) is fitted into its own fixed seat (45, FIG. 7) formed by drilling a hole in the aluminum cover (L) of the engine head. The cover (L) constitutes a valve train support, which will be described in detail later.
[0017]
By cooperating the partial spherical surface of the recess (14) and the end (41) of the spigot (42), the spigot reciprocates so that the rocker arm (B) actuates the valve (V). The rocker arm can also be rotated laterally around it. In particular, it can be seen that the rocker arm can rotate about axis X (FIG. 4) and spigot (42) to provide some self-adjustment for the purposes described below.
[0018]
The locker (B) has a lateral opening 15 for fitting a pivoting trunnion (16) at one end, and the trunnion (16) has two recesses (17) back to back, The recess is pressed against the head of the handle of the valve (V) and adjusts itself by the relative movement of the rocker arm (B) of the valve shaft, which may vary depending on the type of engine.
[0019]
The other end of the rocker (B) has a needle roller bearing and is disposed on a shaft (20) extending through an opening (22) provided in the flanges (12) and (12 ′). The rolled roller (R) is fitted.
[0020]
As mentioned above, the rocker with the fulcrum in the hemispherical recess (14) automatically compensates for any inadequate lateral movement, thus eliminating the convex outer surface required by normal design Thus, the roller (R) is very simple with a straight cylindrical outer surface that fits closely to the outer surface of the cam (C).
[0021]
To keep the trunnion (16) in place at the first end of the rocker, an elastic lamina (25) is used with the flange (26) folded back so that the lower part is attached to the rocker flange. (See FIG. 5). The elastic lamina has an inlet (27) at the top for lubricating the trunnion (16).
[0022]
A second elastic lamina (30) with the flange (31) folded over the hemispherical recess (14) to limit the relative lateral movement of the spigot (42) of the tappet (4). Installed. The thin plate (30) can be made of spring steel so that the rocker arm (B) can be attached to the cover (L) by simply snapping over the head (41) of the spigot (42). Has an opening. In this way, the thin plate (30) holds the rocker arm (B) in contact with the cover (L) without hindering the rocker arm (B) from performing the intended movement during operation. .
[0023]
In this embodiment, the protrusion, i.e. spigot (42), has a relatively narrow neck that leads to an enlarged, partially spherical head (41), so that it is slightly larger than the diameter of the neck. An opening in the thin plate (30) having a diameter can be used to hold the rocker arm in place. As shown in FIG. 4, this opening makes it easier to fit the rocker arm into the tappet (4) and to some extent in the longitudinal direction to ensure proper engagement between the camshaft and the valve. Preferably, the longitudinal axis is an elongated opening extending substantially parallel to the length of the rocker arm so that free movement is possible. However, other configurations are possible. For example, the rocker arm extends through the rocker arm into a recess at the end of the head (41) and is possibly elastically enlarged to engage with a thread or an annular ridge in the recess It can be fixed to the head (41) by a rivet that engages the recess by part or by other members. In any case, it is desirable that the means for attaching the rocker arm to the fulcrum is fairly loose and is arranged so as not to interfere with the intended movement during operation of the rocker arm.
[0024]
FIG. 7 shows that the rocker (B) is kept pressed against one end of the valve head (V) by the pivoting trunnion (16) and the other end is pressed against the cam (C) by the roller (R). It is detail drawing of the tappet (4) kept in a state. The spigot (42) that supports the hemispherical head (41) that forms the fulcrum of the rocker is accurately inserted into the seat (45) formed by drilling the cover (L) of the engine block A plunger attached to the chamber (43) that slides into the formed sleeve (44). There is a high pressure tappet chamber (47) in the lower part of the chamber (43), on top of which there is a plunger (48) that houses a low pressure oil tank (49). Oil is supplied through the inlet (50) and the flow path (51) in the cover (L).
[0025]
Inlets (46) and (46 ') are provided in the spigot (42) to lubricate the hemispherical end (41) which acts as a fulcrum.
[0026]
By way of example, FIGS. 8 and 9 show the aforementioned rockers (B1), (B2),... Operating valves V1, V2,... Of an internal combustion engine with a single central camshaft (A). The configuration of the valve control train using. Is shown from the side and from above.
[0027]
By using such a configuration, assembly of the engine is facilitated. The cylinder head of the engine has a lower head portion (65) to which valves (V1) and (V2) are attached. These springs (M) are arranged in the recess (60) of the lower head (65).
[0028]
On the valve train support formed by the cover (L), rocker arms (B1) and (B2) are attached in a separate process, along with any other rocker arms required for the engine (see FIG. 9). . Thus, this constitutes a self-supporting assembly that can be manufactured and sold separately from the rest of the engine and can be provided in an assembled state ready for installation on the engine. In this way, the pre-assembly of the valve support not only facilitates the entire assembly, but the individual assembly of the rocker arms can be performed as a separate process, making the final assembly of the engine significantly easier. .
[0029]
If desired, the manufacturer can supply various types of valve supports, all mounted on the same engine head, but made to different specifications. For example, one type may have a hydraulic lash adjuster and a rocker arm with a roller, and a less expensive one is a mechanical lash adjuster and a non-roller fixing on the rocker arm. The cam engagement surface may be provided. This facilitates the production of various types of engines suitable for the customer while allowing the assembly procedure to be simplified.
[0030]
The position of each fulcrum on the cover (L) can be selected so that all the rocker arms are the same length, and can therefore be configured exactly the same if desired.
[0031]
The camshaft is preferably attached to the cover (L) during the pre-assembly process.
[0032]
FIGS. 10 and 11, where the same reference numbers represent the same integers, show another embodiment of the invention in which twin camshafts (A1, A2) drive each row of rocker arms (B). An aluminum valve train support (L) is best shown in FIG. 11 which shows exactly the same rocker arms (B) mounted in two rows, with the arms in each row driving the intake and exhaust valves. In order to be properly positioned. Although not shown in FIG. 11, the camshafts (A1, A2) are also preferably attached to the support (L) before the entire assembly is mounted on the lower cylinder head of the engine.
[0033]
The support (L) of any embodiment preferably has a flow path for distributing oil to the valve train. In fact, all the oil flow paths can be arranged in the support body.
[Brief description of the drawings]
FIG. 1 is a side view of a prior art rocker arm.
FIG. 2 is a side view, partly in section, of a rocker arm device according to the invention applied to a valve.
3 is a side view of the rocker arm of FIG. 2. FIG.
4 is a plan view of the rocker arm shown in FIG. 3. FIG.
FIG. 5 is a cross-sectional view taken along line VV in FIG.
6 is a cross-sectional view taken along line VI-VI in FIG.
FIG. 7 is a cross-sectional view through a hydraulic tappet forming the fulcrum of the rocker arm.
FIG. 8 is a cross-sectional view of a valve train support of the present invention that controls two rows of valves with a single central camshaft.
9 is a plan view of the valve train support shown in FIG. 7. FIG.
FIG. 10 is a side view showing another embodiment of the valve train assembly according to the present invention.
11 is a perspective view of the valve train support of the assembly of FIG. 10 as viewed from below.

Claims (18)

A valve train support having a plurality of individual rocker arm fulcrums;
A plurality of rocker arms each attached to each rocker arm fulcrum and pivotable about said rocker arm fulcrum;
A valve train assembly comprising:
Each rocker arm, for mounting the rocker arm on the rocker arm fulcrum circle over the corresponding said rocker arm support point, with perforated sheet made of an elastic member, forming the valve train assembly of free-standing And
Each rocker arm has a partial spherical surface that fits into the corresponding surface of the rocker arm fulcrum to which the rocker arm is mounted, and about an axis along the length of the rocker arm to allow self-adjustment Is rotatable,
The valve train assembly is manufactured separately from the internal combustion engine and can be operably attached to the internal combustion engine such that the rocker arm is movable by a cam to actuate the valve of the internal combustion engine. The valve train assembly is manufactured as follows. The valve train assembly of claim 1, wherein each rocker arm fulcrum forms part of a lash adjuster. The valve train assembly according to claim 2, wherein each lash adjuster is a hydraulic lash adjuster. Each rocker arm constitutes a first kind lever, the valve train assembly according to any one of claims 1 to 3. Each rocker arm is formed by deforming the thin plate, the valve train assembly according to any one of claims 1 to 4. Each rocker arm is formed by deforming the sheet, by the deformation, the said partial spherical surface rocker arm Ru fitted in the corresponding face of the rocker arm fulcrum attached is also formed, according Item 5. The valve train assembly according to any one of Items 1 to 4. The valve train assembly according to any one of claims 1 to 6 , wherein the rocker arms are all substantially the same length. The valve train assembly according to claim 7 , wherein the rocker arms are all substantially identical. Each rocker arm has a pivoting member which engages the valve, the valve train assembly according to any one of claims 1 to 8. Wherein the at least one camshaft mounted in the valve train assembly also has, valve train assembly according to any one of claims 1 9. Wherein the valve train support, wherein a flow path for feeding oil to the rocker arm pivot is formed inside the valve train assembly according to any one of claims 1 1 0. Each rocker arm supports a roller which engages the cam of the cam shaft, each roller has a substantially flat cylindrical outer surface, item 1 any of claims 1 1 1 A valve train assembly according to claim 1. The valve train support supports the rocker arm for the intake and exhaust valves for a plurality of cylinders, the valve train assembly according to any one of claims 1 1 2. Each has a plurality of cylinders having an intake and exhaust valve, the valve train support supports a rocker arm for the intake and exhaust valves, any one of claims 1 1 3 1 An internal combustion engine comprising the valve train assembly according to the item. (A) providing a valve train support having a plurality of individual rocker arm fulcrums;
(B) the rocker arm, the covers corresponding said rocker arm pivot mounted in the rocker arm pivot by perforated sheet made of full elastic member, the valve train assembly of free-standing is formed, and, Each rocker arm has a partial spherical surface that fits into the corresponding surface of the rocker arm fulcrum to which the rocker arm is mounted, and about an axis along the length of the rocker arm to allow self-adjustment Attaching the rocker arms to each rocker arm fulcrum so that the
(C) A cylinder of an internal combustion engine manufactured by separating the valve train support body to which the rocker arm is attached from the valve train support body so that each rocker arm is in an operating relationship with each engine valve. Attaching to the head,
A method of assembling an internal combustion engine. Wherein the valve train support before attachment to the cylinder head, and a step of mounting at least one camshaft to the support The method of claim 1 5. 17. A method according to claim 15 or 16 , comprising forming each rocker arm by deforming a lamina. Forming said partial spherical surface on each rocker arm by deforming said thin plate so that said partial spherical surface is fitted to said corresponding surface of said rocker arm fulcrum. 18. The method according to 17 .

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