JPH0128203B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention primarily relates to a valve operating cam device for a vehicle engine.

Conventionally, this type of device is known in which the opening and closing of the intake and exhaust valves of an engine are controlled by a cam on a valve drive camshaft via a rocker arm that engages with the valve, but in this case, the rocker arm has a torque. It should be equipped with an adjuster screw or other gap adjusting member to adjust the pet clearance. In this case, if the distance between the adjusting member and the slipper with which the cam engages is short, depending on the valve timing adjustment, The cam and adjustment member will collide, making it impossible to obtain the necessary valve timing.In order to avoid this, increasing the distance between the adjustment member and the slipper will lengthen the rocker arm itself, increasing its weight. Surging, jumping, etc. occur and the engine speed decreases, which is undesirable because it leads to a decrease in engine output. Furthermore, if the load of the valve spring is set high to prevent this, the operating load of the valve will become extremely high, resulting in increased mechanical loss for driving, which is also undesirable and leads to a decrease in output.

The object of the present invention is to provide a device in which a rocker arm and a cam can be installed without increasing the distance between the adjusting member and the slipper in order to improve the above-mentioned disadvantages. In a device in which the opening and closing of a valve is controlled by a cam on a valve drive camshaft via a rocker arm, the cam is divided into at least two halves at appropriate intervals on the camshaft, and the rocker arm A gap adjustment member is provided so as to face within the gap. An example of implementing the present invention will be explained with reference to the attached drawings. In the drawings, reference numeral 1 indicates a valve in the intake and exhaust system of the engine, and the valve 1 has a rocker arm 2 on the upper side that engages with the valve 1.
The opening/closing is controlled by the cam 4 on the valve drive camshaft 3 above it.

According to the invention, the cam 4 is arranged at least in both halves 4 at a suitable distance 5 on the shaft 3, as clearly shown in FIG.
a and 4a, and a gap adjustment member 6 is provided facing the rocker arm 2 within the gap 5.
We prepared the following. The member 6 consists of an adjusting screw 6a that passes through the arm 2 and extends downward, and a nut 6b at the top thereof. Furthermore, in the illustrated example, the rocker arm 2 is divided into a pair of left and right halves 2a, 2a corresponding to the halves 4a, 4a on the distal end side, as clearly shown in FIG. The member 6 is provided at each location.

Furthermore, in the illustrated example, the valve timing can be freely switched between high speed and low speed. In other words, the camshaft 3 is configured as a high speed camshaft on one side, and this is connected to the cam 4 of the arm 2. A camshaft 7 for low speed is provided on the other side, and a cam 8 on the shaft 7 is engaged with the root side of the arm 2, and furthermore, both camshafts 3 and 7 are connected in common. The camshaft holder 9 is arranged in parallel on a single camshaft holder 9, and the holder 9 is connected to a pair of support shafts 1 on both outer sides concentric with the camshaft 7.
0 and 10, and the camshafts 3 and 7 are engaged with each other by respective gears 11 and 11, and connected to the crankshaft of the engine by a cam sprocket 12 at one end thereof. Thus, as the holder 9 swings, both cams 4 and 8 move toward the arm 2.
Therefore, the valve 1 is shown in FIG.
The state in which the valve opens and closes according to the high-speed valve lift curve shown in FIG.
Therefore, the valve 1 is shown in FIG.
It is possible to freely open and close the valve according to the low-speed valve shift curve shown in the figure. The holder 9 is provided with an arm 13 for swinging the holder 9, and a second gap adjustment member 15 is provided at the tip of the arm 13 between it and a stopper 14 in front of it. The member 15 is composed of an adjusting screw 15a and a nut 15b in substantially the same manner.

As described above, according to the present invention, the cam on the camshaft is divided into at least two halves with an appropriate interval, and an adjustment member is provided facing within the interval, so that the adjustment member and the cam are engaged. Since the adjustment member can be freely adjusted without increasing the distance between the locker arm and the slipper, the locker arm can be made relatively short in length, which has the effect of making the entire rocker arm relatively compact.

[Brief explanation of drawings]

Fig. 1 is a front view of one example of the device of the present invention, Fig. 2 is a cross-sectional view taken along the - line, Fig. 3 is a cross-sectional view taken along the - line, Fig. 4 is a plan view of the rocker arm, and Fig. 5 is the operation. It is a characteristic line diagram. 1... Valve, 2... Locker arm, 3... Valve train camshaft, 4... Cam, 4a, 4a... Both halves,
5... Spacing, 6... Gap adjustment member.

Claims (1)

[Scope of Claims] 1. In a device in which the opening and closing of the valves of the intake and exhaust system of an engine are controlled by cams on a valve drive camshaft via a rocker arm, the cams are connected to at least two cams at appropriate intervals on the camshaft. A valve operating cam device for an engine, which is divided into two halves and includes a gap adjusting member facing the rocker arm within the gap. 2. A valve operating cam device for an engine as set forth in claim 1, wherein the rocker arm is branched into both halves at the distal end side, and the adjusting member is provided at the merging point.