JP3183110B2 - Engine rocker shaft mounting structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rocker shaft mounting structure for an engine, and more particularly, to a rocker arm type OHC which pushes a stem head of a valve via a rocker arm.
The present invention relates to a rocker shaft mounting structure for an engine having a structure.

[0002]

2. Description of the Related Art An engine of this type employs a structure in which a rocker shaft is fixed to a cam cap (cam bracket) fixed to an upper surface of a cylinder head, for example. In this case, as shown in FIGS. 6 and 7, for example, the rocker shaft 60 is processed to form a lower flat portion 66 for stable mounting on the mounting flat portion 64 of the cam cap 62, and tightening is performed. An upper flat portion 70 is formed so that the head of the bolt 68 can be stably seated, and is integrally connected by a tightening bolt 68. 6 and FIG.
74 denotes a rocker arm, 76 denotes a cam, and 78 denotes a cylinder head upper surface.

[0003] Further, as shown in FIG.
A rocker shaft cap 88 having an inner peripheral surface 84 along the outer peripheral surface of the rocker shaft 82 formed by so-called round processing on the mounting flat portion of the zero,
, And are integrally connected by a tightening bolt 90.

[0004]

By the way, in the rocker arm type OHC structure, if the structure is reduced in size, the diameter of the rocker shaft is naturally limited in order to avoid interference with the cam profile P shown by a two-dot chain line in FIG. Come. On the other hand, the rocker shaft is required to have high rigidity in terms of its function or a structure in which an oil passage for lubricating oil must be formed to the rocker arm. Considering from this viewpoint, the conventional technique of performing flat processing on the rocker shaft has an advantage that the number of parts is small and processing is easy, but the problem of insufficient strength cannot be avoided.

Further, in the prior art for performing round processing on a cam cap or the like, although the rigidity of the rocker shaft is not reduced, the concentricity with the rocker shaft is required, so that the processing is not easy. was there. An object of the present invention is to provide a rocker shaft mounting structure of an engine that does not cause a decrease in the rigidity of a rocker shaft, does not require high-precision machining, and can be applied without modifying the current layout. .

[0006]

In order to achieve the above object,
According to the first aspect of the present invention, the cam cap having the mounting flat portion is fixed to the upper surface of the cylinder head, and the cam cap is fixed to the cylinder head.
Of the engine that fixes the round rod-shaped rocker shaft to the
In the camshaft mounting structure, a cylindrical shape having a lower flat surface portion applied to the mounting flat surface portion of the cam cap, an upper flat surface portion on which a bolt head is seated, and a slit formed in one side portion extending in an axial direction. Is provided,
The inner diameter of the spacer is slightly larger than the outer diameter of the rocker shaft.
Large enough to pass the rocker shaft smoothly
Pipe member, and the spacer is mounted on the spacer in the axial direction.
With the rocker shaft passed through, the upper flat portion, the rocker shaft, the lower flat portion, and the cam cap are integrally connected by a tightening bolt that penetrates in series. According to the invention described in claim 2, the engine described in claim 1 is provided.
In the rocker shaft mounting structure of
At one end of the shaft, the upper and lower planes
For positioning the rocker shaft in the rotational direction
The spacer is press-fitted and fixed .

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. The cam cap 2 fixed to the upper surface of the cylinder head has a mounting flat portion 4, on which a spacer 6 is placed. A round bar-shaped rocker shaft 8 that has not been subjected to any processing for fixing is passed through the spacer 6 in the axial direction. Each member of the spacer 6, the rocker shaft 8, and the cam cap 2 is fixed by a tightening bolt 10. They are joined together.

As shown in FIG. 2, the spacer 6 has a lower flat portion 12 at the lower end for stably mounting on the mounting flat portion 4 of the cam cap 2, and a tightening bolt 1 at the upper end.
The zero bolt head 10a is formed in a cylindrical shape having an upper flat portion 14 for stable seating, and a slit 16 extending in the axial direction is formed on one side. Further, bolt insertion holes 18 and 20 are formed in the lower plane portion 12 and the upper plane portion 14, respectively. Correspondingly, a bolt insertion hole 22 is also formed in the rocker shaft 8. The spacer 6 shown in this example is obtained by cutting the upper and lower surfaces and side portions of a pipe member having an inner diameter slightly larger than the outer diameter of the rocker shaft 8 and having a size capable of smoothly passing the rocker shaft 8. The width w of the slit 16 is set such that a slight gap still remains when the slit 16 is tightened with the tightening bolt 10 through the rocker shaft 8. The concentricity of the shaft hole of the spacer 6 with respect to the rocker shaft 8 is already held by the pipe member itself at the time of material selection, and when tightened, the inner surface of the slit 16 depends on the degree of freedom due to the presence of the slit 16. Fits the outer surface with high precision. Therefore, the processing required for the spacer 6 is only a simple planar processing that does not require precision and does not require skill.

As shown in FIG. 3, a bolt insertion hole 24 is formed in the cam cap 2, and a screw hole 28 into which the tightening bolt 10 is screwed is formed in the upper surface 26 of the cylinder head. In FIG. 3, reference numerals 30 and 32 denote rocker arms. In FIG. 1, the rocker arms 30, 32 and the upper surface 26 of the cylinder head are omitted. In FIG. 1, reference numeral 34 denotes a cam.

A practical assembling operation will be described. As shown in FIG. 4, a spacer 36 having a press-fit and fixed structure is fitted to one end of the rocker shaft 8 to position the rocker shaft 8 in the rotation direction, and then the rocker arm 38 is sequentially arranged. , Color member 4
0, rocker arm 30, spacer 6, rocker arm 32
Pass through. Thereafter, a tightening bolt is inserted from the upper plane portion 14 of the spacers 6 and 36 and integrally joined as shown in FIG. When a spacer 36 having a press-fitting fixed structure is fitted to one end,
It is possible to obtain the function of preventing the child parts from falling off during sub-assembly. The spacers 6 and 36 are provided on the rocker arms 30 and 3.
Because it also has a function as a thrust receiver for 2,38,
Compared to the conventional unstable positioning in the thrust direction using only the cam cap 62 as shown in FIG. 7, stable positioning can be performed.

Next, FIG. 5 shows another embodiment. The spacer 42 in this example is the cam cap 2
A lower half portion 46 having a lower flat portion 44 applied to the mounting flat portion 4 and an upper half portion 50 having an upper flat portion 48 on which a bolt head is seated, are formed into a cylindrical shape in a combined state. The structure is formed. In addition, it is set so that a slight gap e is formed on both sides when the bolt is fitted to the rocker shaft 8 and tightened. The spacer 42 shown in this example can also be easily formed by dividing a pipe member having concentricity with the rocker shaft 8 in advance. Such a split configuration has the advantage that there is no restriction on the order of insertion into the rocker shaft 8 as compared with a single-unit configuration, and so-called retrofitting can be performed arbitrarily.

[0012]

As described above, according to the present invention, the rocker shaft can be stably mounted on the existing layout of the cam cap, and the rocker shaft can be machined through the spacer having the flat portion on which the bolt head is stably seated. Therefore, the rigidity of the rocker shaft can be prevented from lowering. In addition, since a process that requires concentricity accuracy with respect to the rocker shaft is not required, manufacturing can be facilitated, and assembling accuracy can be improved.

[Brief description of the drawings]

FIG. 1 is a partially omitted schematic side view showing an example of an embodiment of the present invention.

FIG. 2 is an exploded perspective view of a main part.

FIG. 3 is a schematic sectional view taken along line III-III in FIG. 1;

FIG. 4 is a schematic sectional view showing an assembled state.

FIG. 5 is a schematic side view showing another example of the embodiment.

FIG. 6 is a side view of a conventional example.

FIG. 7 is a sectional view taken along line VII-VII in FIG. 6;

FIG. 8 is a schematic side view showing another conventional example.

[Explanation of symbols]

 2 Cam cap 4 Mounting flat part 6, 42 Spacer 8 Rocker shaft 10 Tightening bolt 10a Bolt head 12, 44 Lower flat part 14, 48 Upper flat part 16 Slit 46 Lower half 50 Upper half

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F01L 1/18

Claims (2)

(57) [Claims] A cam cap having a mounting flat portion is fixed to an upper surface of a cylinder head , and the cam cap has a round bar shape.
Engine rocker shaft fixing the rocker shaft of the engine
In the mounting structure, the cam cap has a lower flat surface portion applied to the mounting flat surface portion, and has an upper flat surface portion on which a bolt head is seated. A spacer is provided, the inner diameter of which is
Slide the rocker shaft slightly larger than the outside diameter of the shaft.
It is formed of a pipe member large enough to pass through
With the rocker shaft passing through the
A rocker shaft mounting structure for an engine , wherein the upper flat portion, the rocker shaft, the lower flat portion, and the cam cap are integrally connected by a tightening bolt penetrating the cam cap. 2. A rocker shaft for an engine according to claim 1.
In the mounting structure, attach one end of the rocker shaft
The rocker shaft has a flat portion and a lower flat portion.
The positioning spacer is press-fitted and fixed.
Engine rocker shaft mounting structure.