JPS59115413A - Valve open/close timing controller - Google Patents

Abstract

PURPOSE:To optimize open/close timing of suction/discharge valve by constructing transmission of cam shaft and crank shaft through a helical gear then moving the cam shaft axially in accordance to operating state. CONSTITUTION:Helical gears 5, 6 are employed in a gear mechanism for driving a cam shaft 2 through a crank shaft 1, then it is co-operated with a hydraulic motion mechanism 10 for moving the cam shaft 2 to move the cam shaft 2 axially in accordance to engine rotation to be provided from a rotation sensor 17 thus to rotate cam shaft 2 and to shift cam phase. Consequently open timing of suction valve and close timing of exhaust valve can be optimized under low and high speeds resulting in improvement of fuel consumption and high speed output.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a valve opening/closing timing control device that varies the opening/closing timing of a valve in a valve train of an internal combustion engine. Related to things that change the opening timing or closing timing.

Regarding the valve timing that affects the valve operating mechanism of an internal combustion engine, there is a problem in the opening timing of the intake valve and the closing timing of the exhaust valve at top dead center. In other words, in the intake valve, there is a delay due to the inertia of the gas after the valve is opened, so it is better to listen early before top dead center to utilize the intake inertia and increase the volumetric efficiency. If it is too fast for the dead center, on the other hand, if it blows back at low speed, it will blow through and lack stability. In addition, for exhaust valves, closing later after top dead center can improve exhaust efficiency by utilizing exhaust inertia, but if the closing timing is delayed in this way, the blowout loss at low speeds will increase and the output will decrease. invite

Therefore, if high-speed performance is emphasized by increasing the volumetric efficiency as well as the intake and 1-in-1 air efficiency, the intake valve opening timing should be set earlier before top dead center, and the exhaust valve closing timing should be set later after top dead center. On the other hand, when low-speed performance is important, it is desirable to set the timing of the intake and exhaust valves close to top dead center in order to avoid the various disadvantages mentioned above.

By the way, conventionally, the cam lift, phase, valve clearance, etc. that determine the valve timing are fixedly set to either low speed or high speed.
It was not possible to obtain the optimum valve timing depending on each operating condition. In order to deal with this problem, various proposals have been made to vary the valve timing according to the operating regulations.
There are prior art techniques disclosed in Japanese Patent Application Laid-Open No. 55-96310. These prior art technologies are equipped with a plurality of cams that form the profile, and these cams are selectively used depending on the operating conditions +t to obtain the desired valve timing. The valve mechanism becomes larger due to factors such as doubling the number of parts.

In view of these circumstances, the present invention provides a variable valve timing device that has a structure that allows the profile and number of cams to be set to the minimum necessary, and that optimizes both low-speed and high-speed valve timing. The purpose is to

For this purpose, the device of the present invention focuses on the point that the opening timing or closing timing of the intake and exhaust valves can be changed by shifting the phases of their cams, and the camshaft and crankshaft are connected by a helical gear. In addition to having a transmission configuration, the camshaft is movable in the axial direction depending on the operating conditions, and the synergistic effect of the axial movement of the camshaft and the south corner leaf of the helical gear A7 rotates the cam together with the camshaft at a predetermined angle. It is characterized by controlling the intake valve opening timing and exhaust valve closing timing to be close to top dead center at low speeds, and to increase them at high speeds by shifting the phase.

Hereinafter, the embodiment of the present invention will be explained with reference to the drawings. Example i will be specifically explained. In Fig. 1, numeral 1 is the crankshaft, 2
is a camshaft, and on this camshaft 2, an intake valve cam 3 and an exhaust valve cam 4 are attached. Therefore, the crankshaft 1 and the camshaft 2 are configured to transmit power by a pair of helical gears 5 and 6 that mesh with each other, and the helical gear 5 on the crankshaft side is meshed with the helical gear 6 on the camshaft side. It is widened to allow for directional movement. In addition, in the several bearings 7, 8.9 of the 20 stages of the camshaft,
A hydraulic moving mechanism 10 is provided in one bearing 7 to move the J:Recam@2 in the axial direction depending on the operating conditions.

In FIG. 2, the mechanism 10 has a cylinder 11 formed around the camshaft at the bearing 7, and a pressure receiving plate 12 integral with the camshaft 2 is inserted into the cylinder 11. The pressure chamber 13 is connected to a high-speed pressure chamber 14 on the other side.
is located. Then, the oil passage 16 from the oil pump 15 is connected to the rotation sensor 1 to 17, for example, at the engine rotation speed of 4
A hydraulic circuit is constructed in the pressure chamber 13.14 through the switching valve 18 and the oil passage 19.20, which are switched by No. E, and in the case of low speed, the pressure chamber 13 is supplied with oil and the pressure chamber 14 is drained.
In the case of high speed, the pressure chamber 14 is supplied with oil and the pressure chamber 13 is drained.

With this configuration, during low-speed operation, the high oil pressure of the oil pump 15 is supplied to the pressure chamber 13 of the hydraulic moving mechanism 10 by the operation of the switching valve 18 by the rotation sensor 17, and the pressure chamber 14 is drained. The pressure receiving plate 12 is pressed to the left side in the figure. Therefore, the camshaft 2 moves to the left in the axial direction, but due to the synergistic effect of this and the angle of the teeth of the helical gear 5.6, the cams 3 and 4 move together with the camshaft 2 to rotate the camshaft 2, as shown by the solid line in Figure 3. It is rotated to the direction lag side, sucks,
The valve timing of the exhaust valve is shown in Figure 4) as shown by the solid line, 5 - angle α on the crank angle trace from the intake valve opening position, i.e., top dead center, to the beginning of the exhaust valve, and the exhaust valve closing position, i.e. - The angle β on the crank angle, which takes the time from dead center to valve closing, becomes small.

Next, fast luck 1! The pressure chamber 14 is supplied with oil by the switching operation of the switching valve 18 by the rotation sensor 17, and the pressure chamber 13 becomes undone, so that the pressure receiving plate 1
2, the 7J ramshaft 2 moves to the right side in the figure, and due to the synergistic effect of this and the tooth angle of the helical gear 5.6, the camshaft 2 and the cam 3.4 move to the advancing side in the rotational direction of the camshaft 2. Rotate a predetermined angle. Therefore, the cam 3.4 is integrally -1-
Compared to the low speed case, the phase is shifted as shown by the two-dot chain line in Figure 3, and the valve timing of the intake and exhaust valves is as shown in Figure 4 (a).
) as shown by the broken line, and the exhaust valve closing angle increases as shown by β'.

Incidentally, the phase shift between the cams 3 and 4, that is, the variable amount of the valve timing can be arbitrarily set by the amount of movement of the cam @2 and the angle of the teeth of the helical gear 5.6.

In addition, in the case of the above-mentioned high-speed operation, if the cams 3 and 4 are rotated further toward the R side in the rotational direction of the camshaft 6-2 and the phase is shifted in the opposite direction to that described above, the broken line in Fig. 1 (()) , the intake valve gap angle increases as α' in the valve timing.

From the above explanation, it is clear that J: sea urchin According to the present invention, sucking,
By shifting the phase of the exhaust valve cams 3 and 4 according to the operating condition A'1, the valve timing can be adjusted to optimally control the intake valve opening timing and exhaust valve closing timing at low and high speeds. , stability at low speeds, fuel efficiency,
Both can improve output at high speed. Helical gear Al is used in the m* mechanism that drives the camshaft 2 by the crankshaft 1.
5 and 6, and by the action of the hydraulic moving mechanism 10 that moves the camshaft 2, the camshaft 2 is rotated and the cam 3.
4, the structure is simple and the operation is reliable.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram showing an embodiment of the device according to the present invention, Fig. 2 is a configuration diagram showing a hydraulic moving mechanism, Fig. 3 is a diagram showing a cam phase shift, Fig. 4(a), Q)) is a diagram showing valve timing. DESCRIPTION OF SYMBOLS 1... Crankshaft, 2... Camshaft, 3.4... Cam, 5.6... Helical gear t, 7, 8.9... Bearing, 10... Hydraulic moving mechanism, 11...Cylinder, 1
2... Pressure receiving plate, 13° 14... Pressure chamber, 15...
Oil pump, 16.19.20...Oil line, 17...
・Rotation 1? 18...Switching valve. Patent applicant Fuji Heavy Industries Co., Ltd. Representative Patent Attorney
Nobuki Kobashi

Claims (1)

[Claims] The camshaft is transmitted to the crankshaft using a pair of helical gears, and the camshaft is moved in the axial direction by the bearing of the camshaft depending on the operating conditions! 171, the hydraulic moving mechanism is configured so that the phases of the cams of the intake and exhaust valves are integrally shifted by the movement of the camshaft by the hydraulic moving mechanism and the action of the helical gear. Valve opening/closing timing control device.