JPH03217608A - Forcedly driving valve device for engine - Google Patents

Abstract

PURPOSE:To finely adjust valve clearance by providing a pin insertedly fitted extending over a retainer and a valve shaft to connect both parts, and forming a plurality of holes on the valve shaft with a prescribed pitch so as to insertedly fit the pin to the selected hole. CONSTITUTION:In a forcedly driving valve device in which a retainer 7 engaging with the valve follower part 11 of a rocker arm 6 is connected to a valve shaft 10, a pin 5 insertedly fitted extending over the retainer 7 and the valve shaft 10 is provided to connect both parts each other. A plurality of holes 13 are formed on the valve shaft 10 with a prescribed pitch so as to insertedly fit the pin 5 in a selected hole. The neighboring holes 13 with each other in the axial direction are formed through the center line of the valve shaft 10 with phase difference of a prescribed angle each other, and the pitch of the holes 13 is formed smaller than the opening diameter (d) of the hole 13. Hereby, the pitch of the holes 13 is sufficiently minified to finely adjust the valve clearance.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an improvement in a forced opening/closing valve device for forcibly opening and closing an exhaust valve of an industrial vehicle. (Prior technology and issues) In order to ensure the followability of the intake and exhaust valves during high-speed engine rotation, a valve-opening cam and a valve-closing cam are formed on the camshaft, and the intake and exhaust valves are forced to open. 2. Description of the Related Art A valve operating device is known in which a valve is opened and closed.

Conventionally, such a valve train is used, for example, in 1986-36.
As shown in FIG. 6, the device disclosed in Japanese Patent No. 502 has a retainer 3 attached to a screw 33 formed on the valve ring 32 of the valve.
6 are screwed together, and the swinging end bolt 35 of the rocker arm 34 engages with this retainer 36, converting the swinging of the rocker arm 34 into reciprocating motion of the valve. By changing the screwing position of the retainer 36, the valve clearance is adjusted.

However, in the case of an exhaust valve subject to a high heat load, the t-cone 33 formed on the valve stem 32 is likely to be deformed, and there is a concern that the valve clearance cannot be adjusted.

Furthermore, since a locking nut 37 for tightening and fixing the retainer 36 is screwed onto the valve shaft 32, there is a problem that the inertial mass becomes large and the degree of freedom in designing around the valve shaft 32 is reduced. Ta.

The present invention aims to solve these problems.

(Means for solving the problem α) In order to achieve the above object, the present invention includes a camshaft that rotates in synchronization with the rotation of the valve, a valve opening cam and a valve closing cam, and a swinging cam that is in sliding contact with each cam. In Ennon's forced opening/closing valve device, which is equipped with a movable rocker arm and a retainer that engages with the swinging tip of the rocker arm, the retainer is fitted onto the valve stem of the valve, and the retainer is inserted across the retainer and the valve stem. A pin is provided to connect the two, and a plurality of holes are formed in the axial direction with a predetermined pinch to allow the pins to be selectively inserted into the valve stem, making it possible to adjust the valve clearance. The holes were formed with a phase difference of a predetermined angle about the center line, and the pitch of the holes was smaller than the opening diameter of the holes.

(Function) Based on the above configuration, as the camshaft rotates, the valve opening cam pushes down the rocker arm to lift the valve via the retainer, and then the valve closing cam pushes up the rocker arm to lift the valve via the retainer. and pull up the valve.

The pin is inserted VF'! By changing the holes in the valve stem, the valve clearance can be adjusted in stages by adjusting the pitch of each hole.

By forming adjacent holes with a phase difference of a predetermined angle from each other about the center line of the valve stem, even if the pitch of the holes is made smaller than the opening diameter of the holes, the adjacent holes will not overlap at the inside of the valve annulus. However, the specified strength can be ensured without overlapping at the outer periphery of the valve. Therefore, the pitch of the holes is not restricted by the diameter of the holes (outer diameter of the pin), and it is possible to finely adjust the valve clearance.

Furthermore, by connecting the retainer and the valve with pins, it is possible to eliminate the need for loose locking nuts, reduce inertial mass, and increase the degree of freedom in design around the valve shaft. Furthermore, since there is no need to form a thread on the valve stem, the valve and retainer can be easily machined, and the durability of the valve can be increased.

(Example) Embodiments of the present invention will be described below with reference to the accompanying drawings.

Figures 1 and 2 show two valves 9 in an ennon equipped with two valves 9 (either an intake valve or an exhaust valve) having the same function for one valve.
Two rocker arms 6 are provided correspondingly. Each rocker arm 6 has a boss 8l that swingably fits into the common rocker shaft 4! +12 is integrally formed, and a valve 7-year lower portion 11 that engages with the valve 9 via the retainer 7 is integrally formed at the tip thereof.

In the figure, 1 is the camshaft 7 that is rotationally driven in synchronization with the ennon.
Two valve opening cams 2 and two valve closing cams 3 are integrally formed on the camshaft 1 in correspondence with the two rocker arms 6.

Each rocker arm 61 pieces (±valve 7 year old lower!'IsII
A push-side cam 7-year lower portion 14 that slides in sliding contact with the valve-opening cam 2 is protruded in an arc shape between the boss portion 12 and a return-side cam 7 lower portion 1 that also protrudes from the boss portion 12 in an arc shape.
5 are integrally formed.

Each valve-closing cam 3 is recessed corresponding to the lifting height when the valve-opening cam 2 pushes down the push-side cam 7-year-old lower part 14, and the valve-opening cam 2
When the valve closing cam 3 tries to pull up the valve 9, the valve opening cam 2 is set so that a predetermined cam blower 7 eel is set. formed, thereby each valve 9
The reciprocating motion is forced.

A retainer 7 that engages with a valve 7 lower portion 11 of the opening arm 6 is connected to the valve shaft 10 of each valve 9.

Each retainer 7 is formed into a cylindrical shape that fits into the valve shaft 10, and two 7-rowers N21.22 protrude annularly from the upper and lower ends of the retainer 7 to sandwich the lower portion 11 of the valve 7 of the rocker arm 6. Valve 7 years old lower part 11 beam retainer 7
The upper and lower parts are 7 years old and the lower part is 21.22 cm.
The area in contact with is formed into a disk shape.

An annular stepped portion 23 is formed at the lower end of each retainer 7,
A valve spring 8 is interposed between the stepped portion 23 and a not-shown shilling head, and each valve 9 is urged in the valve-closing direction.

As shown in FIG.
A single pin 5 is provided to connect the two. Two holes 24 and 25 are formed in the retainer 7, respectively, passing through the upper and lower lower parts 21 and 22 in the radial direction.
can be selectively inserted.

As shown in FIGS. 4 and 5, a plurality of holes 13 are formed in the valve shaft 10 of the valve 9 with a predetermined pitch t in the axial direction, through which the pins 5 can be selectively inserted. It is formed.

Note that the pitch t refers to the distance between the centers of two adjacent holes 13.

The opening diameter d of the hole 13 is formed to be approximately equal to the outer diameter of the pin 5 so that the pin 5 can be inserted without a gap. The outer diameter of the pin 5 is set in accordance with the load applied to the valve 9 to ensure sufficient mounting strength for the retainer 7.

Two adjacent holes 13 are bored with a phase difference of a predetermined angle θ (in this case θ=45″) with respect to the center line of the valve stem 10. As a result, the pitch t of the holes 13 is set to a predetermined value from the opening diameter d of each hole 13. Therefore, in the center of the valve shaft 10, the holes 13 overlap and communicate with each other.

The pitch (distance between centers) of the two upper and lower holes 24 and 25 formed in the retainer 7 should not be an integral multiple of the width of each hole 13 formed in the valve 9, but should be the same as the upper hole 24 and one hole. 13
The lower hole 25 is set to be offset by a predetermined spacing t' from the opposing hole 13 with the pin 5 inserted therein.

Next, the effect will be explained.

As the camshaft 1 rotates, the valve opening cam 2 pushes down the rocker arm 6, thereby lifting the valve 9 via the retainer 7, and then the valve closing cam 3 pushes up the rocker arm 6. Valve 9 through retainer 7
pull up.

In this way, the reciprocating movement of the valve 9 is forcibly performed by the cams 2 and 3, and surging in the high-speed range can be prevented. Valve spring 8 holds valve 9 in the fully closed position.
It functions to seal the combustion chamber by pressing it against a valve seat (not shown), and by making the biasing force relatively small, the reduction in energy consumption is achieved.

The retainer 7 and the valve 9 are connected to each other via one pin 5, and by selectively changing the hole 13 of the valve 9 into which the pin 5 is inserted, the valve clearance can be adjusted in stages with the width of the hole 13. is adjusted to

Further, by selectively changing the holes 24 and 25 of the retainer 7 into which the pins 5 are inserted, the valve clearance can be adjusted by the offset amount t'.

Therefore, the valve 9 into which the pin 5 is inserted and the retainer 7
By selecting the positions relative to each other, the valve clearance can be adjusted with an interval of t-t'.

Two vertically adjacent holes 13 in the valve 9 are drilled with a phase difference of a predetermined angle θ, so that {L1
Even if the pitch t of No. 3 is made smaller than the opening diameter d of the hole 13, although the adjacent holes 13 overlap at the center of the valve narrow 10, overlapping at the outer periphery of the valve shaft 10 can be avoided. 9 can be sufficiently ensured.

In this way, the pitch t of the holes 13 is adjusted to the opening diameter d of the holes 13.
It becomes possible to set the valve clearance to be smaller, and the adjustment width t-t' of the valve clearance can be made sufficiently small, and the valve clearance can be adjusted to the optimum valve clearance.

Further, the structure in which the retainer 7 is connected to the valve 9 using the pin 5 eliminates the need for thread machining on the valve shaft 10 of the valve 9, making machining of the retainer 7 from the valve 9 relatively easy. Furthermore, a locking mechanism for tightening and fixing the retainer 7 is not required, which reduces the inertial mass of the valve train and increases the degree of freedom in design around the valve shaft 10.

(Effects of the Invention) As described above, according to the present invention, in a non-technical forced opening/closing valve device in which a retainer that engages with a rocking tip of a rocker arm is connected to a valve shaft, the retainer is fitted over the retainer and the valve stem. A pin is provided to connect the two, and a plurality of holes into which the pins are selectively inserted are formed on the valve stem with a predetermined pinch so that the valve clearance can be adjusted. The holes are formed with a phase difference of a predetermined angle about the center line, and the pitch of the holes is made smaller than the opening diameter of the hole, making it possible to make fine adjustments to the valve clearance by making the pitch of the holes sufficiently small. In addition, since the retainer is connected via a pin, it eliminates the need for screw machining on the valve stem, increasing workability, improving the durability of the valve, and further reducing inertial mass, making it possible to increase the speed of the engine. I can handle it.

[Brief explanation of drawings]

Fig. 1 is a longitudinal sectional view showing an embodiment of the present invention, Fig. 2 is a plan view, Fig. 3 is a sectional view of the main part, Fig. 4 is a plan view of the valve, and Fig. 5 is a front view of the valve. It is. FIG. 6 is a sectional view showing a conventional example. 1...Camshaft, 2...Valve opening cam, 3...
Valve closing cam, 4...rocker shaft, 5...pin,
6... Rocker arm, 7... Retainer, 9... Valve, 10... Valve shaft, 11... Valve 7 year old lower part,
13... Hole, 14... Push side cam 7-year-old mouth 7 part, 15
...Return side cam 7 lower part, 21.22...7 lower part, 24.25...hole.

Claims (1)

[Claims] A camshaft that rotates in synchronization with engine rotation is provided with a valve-opening cam and a valve-closing cam, a rocker arm that swings in sliding contact with each cam, and a retainer that engages with the swinging tip of the rocker arm. is fitted onto the valve stem of the valve, a pin is fitted across the retainer and the valve stem to connect the two, and holes into which the pins are selectively fitted are formed in the valve stem at a predetermined pitch in the axial direction. A plurality of holes are formed so that the valve clearance can be adjusted, and adjacent holes are formed with a phase difference of a predetermined angle from each other about the center line of the valve shaft, and the pitch of the holes is formed to be smaller than the opening diameter of the hole. Forced opening/closing valve device for engines.