JPS6210407A - Tappet device of v-engine - Google Patents

Abstract

PURPOSE:To aim at both improvement in the intake efficiency and compactness of the constitution of an engine by having a cylinder heat to support one end of a rocker arm as to be rocked by a spherical pivot and arranging each of intake ports of the engine on a line so as to reduce an angle between each of intake ports. CONSTITUTION:The rocker arm 31 of a tappet device 30 is manufactured in the approximately L-shaped form. One end 31a of said arm 31 makes contact with the end face of the valve stem 22a of a poppet valve 22 while the other end 31b has a screw hole 31c thereon. On the other hand, 2 screw part is formed on the end 32a of a spherical pivot 32, and the screw part is screwed into the screw hole 31c of the rocker arm 31 to be projected upwards therefrom. A clamping nut 34 is screwed up to engage with the projecting end so that said end 32a of the pivot can make sliding contact with a recess 33a in a seat metal 33. The curvature of each of the intake ports 21a and 21'a of engines 2 and 2' may then be reduced to a proximity of a straight line so that an angle alphabetween each of the intake ports 21a and 21'a can be reduced greatly and the overlap of carburetors 4 and 5 can also be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention particularly relates to a valve train for a V-type engine mounted on a motorcycle.

(Prior Art and its Problems) In a V-type motorcycle engine that includes a front engine and a V-type engine, and each intake port of each of these engines is arranged between each engine, that is, between banks, each of the intake ports If the angle (hereinafter referred to as the angle) α is large, each intake port and each carburetor connected to each intake port will approach each other and interfere, resulting in
Carburetor placement becomes difficult. Therefore, as shown in FIG. 4, it is necessary to arrange each carburetor as far as possible to the side of the engine in order to reduce interference (overlapping) between the carburetors 4' and 5'.

However, when the carburetor is disposed off to the side of the engine in this manner, the intake ports of each of the engines become more curved, which tends to reduce the intake efficiency. In particular, in a rocker arm type DOHC engine in which the rocker arm shaft of the valve mechanism is located outside the intake and exhaust valves, the intake and exhaust valves.

Since the rocker arm shaft is disposed above the exhaust port, it is not possible to reduce the angle α to a large extent, which poses a major problem in improving the intake efficiency and the resulting engine output. ing.

(Object of the Invention) The present invention has been made in view of the above-mentioned points, and aims to straighten each intake port by reducing the angle of each intake port of the front and rear engines of a V-type engine. Another object of the present invention is to provide a valve train for a V-type engine in which interference between carburetors is reduced.

(Summary of the Invention) In order to achieve the above object, the present invention includes a front engine and a rear engine, each intake port and each carburetor are respectively arranged between these engines, and a rocker arm is used in the valve mechanism. In a valve train for a V-type engine, one end of the rocker arm is brought into contact with an end face of the valve shaft, the other end is disposed outside the valve shaft, and is swingably supported on the cylinder head by a spherical pivot;
The intake ports of each engine are arranged linearly, so that the angle between the intake boats is reduced.

(Example) An embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 shows a cross section of a main part of a V-type engine to which the present invention is applied, and the V-type engine 1 includes a front engine 2 and a V-type engine 2'. 2' intake port 21'a
A carburetor 4.5 is connected to each of the engines 2 and 2', and each intake port 21a and 21'a of each engine 2 and 2' forms a predetermined angle α.

The valve mechanism of the front engine 2 is configured as shown in FIG. No. 22 valve shafts 22a are fitted and arranged to be slidable in the axial direction via the valve guide 23, and the valve umbrella 22b closes the open end of the intake port 21a facing the combustion chamber. Retainer 2 fixed to tip 22c of valve shaft 22a
4 and a retainer 25 disposed on the cylinder head 21 side, valve springs 26 and 27 are concentrically contracted and bias the poppet valve 22 in the valve closing direction.

The rocker arm 31 of the valve train 30 is formed in an abbreviated shape, one end 31a abuts against the end surface of the valve shaft 22a of the poppet valve 22, and the other end 31b is provided with a screw hole 31c.

The spherical pivot 32 has a bolt shape, a hemispherical tip 32a, and a threaded shaft. On the other hand, a pedestal 33 is fitted into a boss 21d provided at a predetermined position above the intake port 21a of the cylinder head 21, and a hemispherical groove 33a is provided approximately in the center of the end surface of the pedestal 33. The threaded portion of the spherical pivot 32 is connected to the rocker arm 31
A fixing nut 34 is screwed into this projecting end, and a hemispherical tip 32a is fitted and slid into a groove 33a on the hemisphere of the pedestal 33. In this state, the approximately central portion 31d of the rocker arm 31 is attached to the cam surface 36a of the camshaft 36.
Contact from below.

The guide plate 35 is bent into an oval shape, and one end 35a is in sliding contact with the tip 31a of the rocker arm 31 so as to sandwich it, and the other end is screwed into a boss 21c protruding from the cylinder head 21 with a bolt 36. and the tip 31 of the rocker arm 31
This prevents the valve shaft 22a from deviating from the distal end surface by preventing the valve shaft 22a from moving laterally. A rib 38 a is provided on the inner circumferential surface of the cover 38 at a position facing the end surface of the threaded portion of the spherical pivot 32 and protrudes from the end surface of the threaded portion at a slight distance, thereby preventing the spherical pivot 32 from rising from the pedestal 33 . Prevent deviations in time. In this way, the fulcrum of the rocker arm 31 is
It is disposed outside the poppet valve 22 to form an outside fulcrum type valve operating mechanism 30.

Each valve operating mechanism (none of which is shown) for the exhaust poppet valve and the intake and exhaust valves of the V-type engine 2' is configured similarly to the valve operating mechanism 30.

By using a spherical pivot type fulcrum instead of the rocker arm shaft that swingably supports the rocker arm as described above, the space at the fulcrum can be reduced, as shown in Figure 1. so each engine 2
.
can be made significantly smaller, and as shown in FIG. 3, the overlap between the carburetors 4 and 5 connected to each intake boat 21a and 21'a becomes smaller.

The action will be explained below.

When the center portion 31d of the rocker arm 31 is pressed by the cam surface 36a as the camshaft 36 rotates, the rocker arm 31 rotates clockwise about the tip 32a of the spherical pivot 32 as a fulcrum, and the springs of the valve springs 26, 27 The valve shaft 22a is pushed down against the force to gradually open the poppet valve 22.

When the poppet valve 22 passes the maximum opening position, the center portion 31d of the rocker arm 31 rotates counterclockwise following the cam surface 36a, and the poppet valve 22
, 27, the valve is gradually closed.

To adjust the tappet clearance, first use the spherical pivot 3.
After loosening the fixing nut 34 of No. 2, this spherical pivot 32
Fit the tip of the driver into the driver groove 32b carved on the end face of the spherical pivot 32 and rotate it to the right or left.
Move forward or backward to adjust the tappet clearance. After this adjustment, the fixing nut 34 is then tightened to fix the spherical pivot 32 in the position.

(Effects of the Invention) As explained above, according to the present invention, the engine includes a front engine and a rear engine, each intake boat and each carburetor are respectively arranged between these engines, and a rocker arm is used in the valve mechanism. In a valve train for a V-type engine, one end of the rocker arm is in contact with the end face of the valve shaft, the other end is disposed outside the valve shaft, and is swingably supported on the cylinder head by a spherical pivot. Since each of the intake boats of the engine is arranged in a straight line and the angle between each intake port is reduced, it is possible to improve the intake efficiency, and accordingly, the output of the engine is improved. At the same time, it is possible to reduce the number of overlapping carburetors, and it is possible to increase the degree of freedom in assembly layout.

Furthermore, there is an effect that the valve mechanism can be made more compact.

[Brief explanation of drawings]

Fig. 1 is a partially cutaway side view of a V-type engine to which the valve train according to the present invention is applied, Fig. 2 is an enlarged sectional view of the main part of Fig. 1, and Fig. 3 is the arrangement of the carburetor 11g. FIG. 4 is a top view showing the arrangement of a conventional carburetor. 1... V-type engine, 2... Front engine, 2
'...Rear engine, 4, 5...Carburetor, 2
2... Poppet valve, 31... Rocker arm, 32...
...Spherical pivot, 36...camshaft.

Claims (1)

[Claims] 1. In a valve train for a V-type engine that has a front engine and a rear engine, each intake port and each carburetor are arranged between these engines, and uses a rocker arm in the valve train, the rocker arm One end is brought into contact with the end face of the valve shaft, the other end is arranged outside the valve shaft, and is swingably supported on the cylinder head by a spherical pivot, and each of the intake ports of each engine is arranged linearly. A valve train for a V-type engine, characterized in that each intake port has a small angle.