JPS6341525Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an engine valve clearance adjustment device that allows easy adjustment of the valve clearance in a swing arm type valve operating device of an engine.

Generally, in a swing arm type valve train for an engine, one end of the rocker arm is in contact with the valve stem, and the other end of the rocker arm is swingably supported at a pivot part.
The cam part swings the rocker arm around the pivot part as a fulcrum to drive the intake and exhaust valves.
Valve clearance must be precisely adjusted so that the intake and exhaust valves open and close at the specified timing.

Conventionally, as a valve clearance adjustment device for an engine equipped with a swing arm type valve train, the pivot part is screwed into the cylinder head and locked with a lock nut, and when adjusting the valve clearance, the lock nut is loosened and the pivot part is moved up and down. There are some that are designed to be displaced by
(see vol.13).

However, with such a valve clearance adjustment device, since the device is housed inside the rocker cover, the rocker cover must be removed each time the valve clearance is adjusted, making the adjustment work complicated. Ta.

This idea was made in view of the above-mentioned conventional problems.In an engine equipped with a swing arm type valve train, the head of the adjustment bolt is positioned outward, and the adjustment bolt is attached to the cylinder at each pivot point. By fitting into the head and forming a cam part on this adjustment bolt that moves the pivot part up and down to adjust the valve clearance to a predetermined value, the valve clearance can be adjusted separately for each valve without removing the rocker cover. An object of the present invention is to provide an engine valve clearance adjustment device that can perform adjustment work.

An embodiment of the present invention will be described below with reference to the drawings.

The drawings show an engine valve clearance adjustment device according to an embodiment of the present invention. In the figure, 1
Reference numeral 1 designates a cylinder head, in which an intake passage 3 is formed which opens into a combustion chamber 2, and cooling water passages 4 are formed at appropriate locations in the cylinder head 1.

A swing arm type valve operating device 5 is provided in the cylinder head 1 and housed in a rocker cover 6. In this valve train 5, reference numeral 7 denotes an intake valve arranged to be seated on a valve seat 8 of the intake passage 3, and a stem 9 of the intake valve 7 slides vertically onto the cylinder head 1 via a valve guide 10. The upper end of the valve stem 9 protrudes above the upper surface of the cylinder head 1, and the retainer 1 is connected to the upper end of the valve stem 9 via a retainer 11.
2 is fixed. A valve spring 13 is provided between the retainer 12 and the upper surface of the cylinder head 1 to bias the valve stem 9 upward.

Further, a rocker arm 14 is disposed above the valve stem 9, one end of which contacts the upper end of the stem 9, and the other end of the rocker arm 14 contacts the pivot portion 1.
5, the pivot portion 1
5 is inserted into an insertion hole 1a formed in the cylinder head 1. Furthermore, a cam 16 is disposed above the rocker arm 14 to swing the arm 14 to open and close the intake valve 7.

The cylinder head 1 is provided with a valve clearance adjustment device 17 for adjusting the valve clearance of the valve train 5. In this adjustment device 17, 18 is an adjustment bolt, which is screwed into the cylinder head 1 with its head 18a protruding outward, and is screwed into the cylinder head 1 by a lock nut 1.
Locked by 9. This adjustment bolt 1
A cam portion 21 that contacts the lower end of the pivot portion 15 is formed at the tip of the pivot portion 8 . Note that 20 is an O-ring for sealing.

Also, although the exhaust valve is not shown,
A valve clearance adjustment device is constructed in exactly the same manner as described above.

Next, a method for adjusting the valve clearance in this device will be explained.

When adjusting the valve clearance, first, the piston (not shown) in the cylinder having the valve to be adjusted is placed at the top dead center position, and the intake valve 7 and the exhaust valve (not shown) are fully closed. In this state, the lock nut 19 is loosened to unlock the adjustment bolt 18, and then the head 18a of the adjustment bolt 18 is rotated clockwise. Then, the cam portion 21 rotates clockwise and pushes the pivot portion 15 upward, thereby gradually reducing the valve clearance of the intake valve 7. If the adjustment bolt 18 is further turned after the valve clearance has become zero, the valve spring 13 will begin to be compressed, but normally the spring force of the valve spring 13 is quite large, and after the valve clearance has become zero, the valve spring 13 will begin to be compressed. The adjustment bolt 18 is almost unable to rotate due to the drag force of the valve spring 13. Therefore, after turning the adjustment bolt 18 until it can no longer be rotated to reduce the valve clearance to almost zero, from that state, adjust the adjustment bolt 18.
is returned to a predetermined angle counterclockwise to set the valve clearance to a predetermined value, and the lock nut 19 is tightened to lock the adjustment bolt 18. In this way, the valve clearance of the intake valve 7 can be adjusted to a predetermined value. Further, the valve clearance of the exhaust valve is also adjusted in the same way as for the intake valve 7. Also, the valve clearances of the intake and exhaust valves of other cylinders may be adjusted in the same manner as above.

Therefore, in this embodiment, the valve clearance is adjusted by turning the adjustment bolt from the outside of the cylinder head, so there is no need to remove the rocker cover each time an adjustment is made, and each valve can be adjusted separately. Therefore, it is possible to easily adjust the valve clearance which varies between each valve. In addition, compared to the conventional device, this device only requires an adjustment bolt having a cam portion, so the structure is very simple.

As described above, according to the present invention, in an engine equipped with a swing arm type valve train, an adjustment bolt is provided with its head positioned outward and fitted into the cylinder head of each pivot portion. Since the adjustment bolt has a cam part that moves the pivot part up and down to adjust the valve clearance to a predetermined value,
There is no need to remove the rocker cover each time adjustment is made, each valve can be adjusted separately, valve clearance adjustment work is very easy, and the structure is also very simple.

[Brief explanation of the drawing]

The drawing is a partial sectional view of an engine having a valve clearance adjustment device according to an embodiment of the present invention. 1...Cylinder head, 9...Valve stem,
14...Rotzker arm, 15...Pivot part,
18...adjustment bolt, 18a...head, 21...
Cam part.

Claims (1)

[Scope of utility model registration request] In an engine equipped with a rocker arm in which one end contacts the valve stem and the other end is swingably supported by a pivot part, the rocker arm contacts the lower end of the pivot part, and its rotation displaces the pivot part up and down, thereby improving valve clearance. An adjusting bolt equipped with a cam portion for adjusting to a predetermined value is provided for each pivot, and is fitted into a cylinder head, with the head of the adjusting bolt located outside the cylinder head. valve clearance adjustment device.