JP2570479Y2 - Valve drive for internal combustion engine - Google Patents

Description

[Detailed description of the invention] <Industrial application field> The present invention relates to a valve drive device for an internal combustion engine, and particularly to a device for simultaneously opening and closing a plurality of intake valves or exhaust valves (hereinafter referred to as intake / exhaust valves). About.

<Prior Art> As a conventional example of this type of valve driving device for an internal combustion engine,
There is something as shown in the figure (Japanese Utility Model Publication No. 1-99909,
See Japanese Utility Model Laid-Open No. 1-127904).

That is, two intake / exhaust valves 1 and 2 are arranged in parallel, and a support member 3 is provided upright between the intake / exhaust valves 1 and 2. A substantially T-shaped valve bridge 4 is attached to the support member 3 so as to be movable vertically in the drawing.

Each side of the valve bridge 4 has an intake / exhaust valve 1, 2
The base end of the valve shaft is engaged.

The rocker arm 6 is swung about the rocker shaft 7 by the reciprocating movement of the push rod 5. As a result, the valve bridge 4 is moved down by the distal end of the rocker arm 6 against the elastic force of the valve springs 8, 9, and the intake and exhaust valves 1, 2 are simultaneously driven to open.

By the way, since the valve bridge 4 reciprocates vertically without rotating about the support member 3, the distal end of the rocker arm 6 comes into contact with the contact portion of the valve bridge 4 so as to reciprocate at substantially the same position. In addition, there is a problem that the contact portion of the valve bridge 4 is easily worn.

In view of the above, there has been proposed a method in which a chip in which a high-hardness sintered material is welded is pressed into a contact portion of a valve bridge to suppress the abrasion. However, this method has a disadvantage that the cost is increased.

Further, as shown in Japanese Utility Model Laid-Open Publication No. 64-44303, the outer peripheral portion of the end member abuts against the edge of the hollow hole of the valve bridge and is freely rotatably mounted in the hollow hole of the valve bridge. Although a device in which the tip portion abuts has been proposed, there is a problem that the contact area between the valve bridge and the end member is small, the surface pressure is increased, and the end member is worn.

The present invention has been made in view of such circumstances, and an object of the invention is to provide a valve drive device capable of suppressing wear while suppressing an increase in cost.

<Means for Solving the Problems> For this reason, according to the present invention, a hole is formed in the upper part of the valve bridge with which the tip of the rocker arm abuts, and a rod-shaped member having the same cross-sectional shape over the entire length is formed in the rod-shaped member. One end of the member is pressed upward by projecting upward from the valve bridge, and a crown-shaped bridge cap which has been subjected to a heat treatment for improving wear resistance is rotatably mounted on the upper end of the rod-shaped member. The top end of the rocker arm is brought into contact with the upper surface.

<Operation> In this manner, by rotating the bridge cap, the contact portion of the bridge cap with the rocker arm is displaced, and wear of the bridge cap and the rocker arm is suppressed, and thus, the contact portion of the bridge cap with the rocker arm. In addition, the use of a material having good wear resistance is not required, and the cost is reduced.

In addition, since a rod-shaped member having the same cross-sectional shape is press-fitted into a hole formed at the upper portion of the valve bridge, and the bridge cap is placed here, the adoption of the valve driving device according to the present invention significantly increases No design change is required.

Furthermore, since the bridge cap is subjected to a heat treatment for improving abrasion resistance, the wear of the contact surface of the bridge cap contacting the tip of the rocker arm is further reduced, and the reliability and durability of the internal combustion engine are reduced. improves.

<Embodiment> An embodiment of the present invention will be described below with reference to FIG.

In the drawing, a support member 11 on a rod is erected on a cylinder head (not shown), and a substantially T-shaped valve bridge 12 is attached to the support member 11 so as to be freely reciprocable in the vertical direction in the figure. .

A hole 13 is formed in the center of the upper part of the valve bridge 12, and a pin 14 as a rod-like member is press-fitted into the hole 13 with its upper part protruding upward from the valve bridge 12. Since the pin 14 has a shape having the same cross-sectional shape over the entire length, that is, a shape having no stepped portion, for example,
Inexpensive materials such as roller bearing materials can be used.
Also, a crown-shaped bridge cap is provided at the upper end of the pin 14.
The rocker arm 15 (not shown) abuts on the upper surface of the bridge cap 15. The bridge cap 15 is made of chrome steel or chromium molybdenum steel that has been subjected to heat treatment such as carburizing and tempering.

A valve shaft base end of one intake / exhaust valve (not shown) is engaged with an engagement hole 16 on one side of the valve bridge 12, and a lower end of an adjustment screw 17 on the other side is engaged with the other end. A base end of a valve shaft of an intake / exhaust valve (not shown) is engaged.

Reference numeral 18 denotes a lock nut, and reference numerals 19 and 20 denote spring seats of intake and exhaust valves.

According to such a configuration, the bridge cap 15 rotates about the pin 14 in accordance with the opening / closing operation of the intake / exhaust valve, so that the sliding contact position between the bridge cap 15 and the rocker arm changes, and the Since uneven wear does not occur and the entire body wears on average, wear of the bridge cap 15 and the rocker arm sliding portion can be suppressed. Further, since the abrasion is suppressed, the bridge cap 15 can be made of a material having lower abrasion resistance than the conventional one, and the cost can be reduced. Furthermore, the pin 14 is pressed into the hole 13 of the valve bridge 12 to
The bridge cap 15 is placed on 14 so the hole
It is easy to process 13 and so on, which can also reduce the cost.

Here, since the pin 14 has a shape having no stepped portion, the manufacturing cost of the pin 14 can be reduced, and, for example, a roller bearing material or the like can be used, thereby further reducing the cost. be able to.

In addition, the valve bridge 12 is heat-treated to improve wear resistance, so that the abutment surface of the bridge cap 15 in contact with the tip of the rocker arm is further reduced, and the valve clearance is adjusted. The frequency of
The reliability and durability of the internal combustion engine are improved.

<Effects of the Invention> As described above, in the present invention, the rod-shaped member is pressed into the hole of the valve bridge, the bridge cap is rotatably mounted on the upper end of the rod-shaped member, and the tip end of the rocker arm abuts on the bridge cap. As a result, wear of the bridge cap and the sliding portion of the rocker arm can be suppressed, and the cost can be reduced.

Further, since the rod-shaped member has a shape having the same cross-sectional shape over the entire length, that is, a shape having no stepped portion, the manufacturing cost of the rod-shaped member is reduced, and for example,
Roller bearing materials and the like can be diverted, and the cost can be further reduced.

In addition, since the bridge cap has been subjected to heat treatment to improve wear resistance, the wear on the contact surface of the bridge cap that contacts the rocker arm tip is further reduced,
The reliability and durability of the internal combustion engine can be improved.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing one embodiment of the present invention, and FIG. 2 is a configuration diagram showing a conventional example of a valve driving device. 12 ... valve bridge, 13 ... hole, 14 ... pin, 15 ...
Bridge cap

Claims (1)

(57) [Scope of request for utility model registration] An end of a rocker arm is brought into contact with an upper portion of a valve bridge abutting on a valve shaft end of a plurality of intake valves or exhaust valves, and the rocker arm swings to reciprocate the valve bridge to thereby reciprocate the plurality of intake valves. A valve driving device for an internal combustion engine wherein a valve or an exhaust valve is simultaneously opened and closed, wherein a hole is formed in an upper portion of the valve bridge, and the rod has the same cross-sectional shape over the entire length of the hole. One end of the rod-shaped member is protruded upward from the valve bridge and press-fitted, and a crown-shaped bridge cap which has been subjected to a heat treatment for improving abrasion resistance is rotatably mounted on the upper end of the rod-shaped member. A valve drive device for an internal combustion engine, wherein a tip portion of a rocker arm is brought into contact with the valve drive device.