JPH10159522A - Variable valve timing and lift mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a variable valve timing and lift mechanism, which is excellent in high speed rotation ability and reliability more than those of conventional same model mechanism in a mechanism wherein the two kinds of cam pieces, for low speed and high speed, that are arranged on the same cam shaft are switched utilizing locker arms. SOLUTION: In this mechanism, two locker arms 4 for low speed and one locker arm 5 for high speed are arranged for two intake valves or exhaust valves. In the next step, at the end of the locker arm 5 for high speed in the side of a locker shaft 8, a receiving body 9 for changing speed is arranged. The receiving body 9 for speed changing is rotated by a shaft 11 for speed changing in the locker shaft 8 which is activated by a solenoid actuator. Through such operation, the clearance between the locker arm 5 for high speed and a cam piece 6, which has a high speed cam profile directly above the locker arm 5 is adjusted.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a four-stroke internal combustion engine. 2. Description of the Related Art Among conventional valve opening / closing mechanisms of a four-stroke internal combustion engine, a type having a DOHC mechanism or an SOHC mechanism has a variable valve timing mechanism. This is because the opening / closing timing of the intake valve (1) or the exhaust valve (2) is switched between when the engine is rotating at a low speed and when the engine is rotating at a high speed. This is a mechanism that attempts to achieve both. Among these mechanisms, the one that is closely related to the present invention is that two types of low-speed and high-speed cam pieces are arranged on the same camshaft (10) and are switched by a switching mechanism using a rocker arm. This is the type of mechanism that will be used. The feature of this type of mechanism is that not only the valve timing but also the valve lift can be varied. [0003] By the way, the conventional mechanism of this kind has some problems. This is because most of them use hydraulic pressure to switch rocker arms. This leads firstly to a complication of the mechanism. This is because it is necessary to secure a hydraulic path and to provide an on-off valve for hydraulic pressure. It is also considered that the reaction speed of the mechanism has a slight delay due to the use of the hydraulic pressure. In the present invention, in order to solve the above-mentioned drawbacks of the conventional variable valve timing mechanism, the rocker arm switching mechanism does not use a hydraulic pressure. , Pure mechanical. FIG. 1 and FIG. 2 are parts lists for two valves of either the intake side or the exhaust side of one cylinder according to the present invention. 3 and 5 are side views of the present invention when the engine is rotating at a low speed. 4 and 6 show side views of the present invention when the engine is rotating at high speed. As can be seen from these figures, in the present invention, when driving two valves on either the intake side or the exhaust side of one cylinder, two valves are required.
Between the low speed rocker arms (4) there is one high speed rocker arm (5). The low-speed rocker arm (4) is driven by a cam piece (3) having a low-speed cam profile immediately above, and the high-speed rocker arm (5) is driven by a cam piece (6) having a high-speed cam profile immediately above. Is done. In the method of mounting the high-speed rocker arm (5), one end thereof is connected to the distal end of the low-speed rocker arm (4) by a component called a connection pin (7). The other end is supported by a speed change passive body (9) which is a component attached to the rocker shaft (8). In addition, as can be seen from any of FIGS. 1 to 6, in the present invention, a part called a speed change shaft (11) exists inside the rocker shaft (8). A groove called a shift gate (12) is formed on the surface of the shift shaft (11). In this groove, there is inserted a connecting member (13) for a speed change passive body, which is a component set so as to penetrate the speed change passive body (9) and the rocker shaft (8). On the surface of the rocker shaft (8), a groove called a gate (16) for a connection member for a transmission shaft is cut. And in this groove, rocker shaft (8)
And a transmission shaft connecting member (14), which is a component set to penetrate the transmission shaft (11). And the speed change shaft (11)
It slides inside the rocker shaft (8) by the force of the electromagnetic actuator (19). As a result, due to the interaction between the transmission shaft connecting body gate (16) and the transmission shaft connecting body (14), the transmission passive body (9) rotates on the rocker shaft (8). FIG. 3, FIG. 5, and FIG. 7 show the state of the present invention when the engine is rotating at a low speed. FIG. 7 is an arrangement diagram of the rocker shaft (8) and the rocker arm group when the present invention is applied to the DOHC in-line four-cylinder engine. In this case, the rocker shaft (8) on the left side of the figure is a perspective view, so that the speed change shaft (11) and other parts inside can be seen. As can be seen from these figures, when the engine is rotating at a low speed, the distal end of the speed change passive body (9) is located below. This is due to the position of the transmission shaft (11) inside the rocker shaft (8). That is, as is clear from FIG. 7, when the engine is rotating at a low speed, the transmission shaft (11)
Is located near the upper side in the figure inside the rocker shaft (8). This is because no current flows through the electromagnetic actuator (19). As a result, the transmission shaft connecting member (14) is located at the end of the bent portion in the transmission shaft connecting member gate (16).
Then, the shifting passive body (9) receiving this action rotates, and as shown in FIGS. 3 and 5, the leading end thereof is positioned below in the figure. As a result, while being supported by the shifting passive body (9), the pressing spring (1
The high-speed rocker arm (5) pressed from above by 7) also has its tip on the rocker shaft (8) side positioned below in the figure. This results in a clearance between the high speed rocker arm (5) and the cam piece (6) with a high speed cam profile directly above it. As a result, the intake valve (1) or the exhaust valve (2) is pushed by the low-speed rocker arm (4) driven by the cam piece (3) having the low-speed cam profile, and opens and closes at the low-speed valve timing. It becomes. On the other hand, FIGS. 4, 6 and 8 show the state of the present invention when the engine is rotating at high speed. FIG. 8 shows the DOHC series 4 according to the present invention.
The arrangement diagram of the rocker shaft (8) and the rocker arm group when applied to a cylinder engine is as follows.
This is the same as in FIG. Naturally, the rocker shaft (8) on the left side of the figure is a perspective view,
FIG. 7 is similar to FIG. 7 in that the internal speed change shaft (11) and other parts are made visible. As can be seen from these figures, when the engine is rotating at a high speed, the tip end of the speed change passive body (9) is located above. And this is also due to the position of the transmission shaft (11) inside the rocker shaft (8). That is, as is apparent from FIG. 8, when the engine is rotating at a high speed, the speed change shaft (11) is located inside the rocker shaft (8) below the figure.
This is because current flows through the electromagnetic actuator (19), and the push rod (18) slides the speed change shaft (11) to the lower side in the figure. As a result, the transmission shaft connecting member (14) is located at the end of the linear portion in the transmission shaft connecting member (16). Then, the shifting passive body (9) that has received this action
Is rotated, and as shown in FIGS. 4 and 6, its tip is located at the top of the figure. As a result, the high-speed rocker arm (5) supported by the speed-changing passive body (9) and pressed from above by the pressing spring (17) also has a tip on the rocker shaft (8) side. Will be located above. As a result, the clearance between the high speed rocker arm (5) and the cam piece (6) with the high speed cam profile immediately above it is zero. As a result, the intake valve (1)
Alternatively, the exhaust valve (2) is directly pushed by the low-speed rocker arm (4), but is indirectly driven by the high-speed rocker arm (5) having a high-speed cam profile. It is under control and opens and closes at high-speed valve timing. The above is the operation of the present invention. FIG. 9 is a side cutaway view of an engine cylinder and a cylinder head, showing an embodiment of the present invention. In this example, it can be understood from the figure that an outer fulcrum type rocker arm in which the rotation axis of the rocker arm is outside the camshaft (10) is introduced. However, the practice of the present invention is not limited to this. It is also possible to introduce an inner fulcrum type rocker arm in which the rotation axis of the rocker arm is inside the camshaft (10). As described above, in the present invention, the variable valve timing mechanism can be switched by a purely mechanical mechanism without using hydraulic pressure. As a result, it has become possible to switch the valve timing at higher speed and more reliably than in the conventional variable valve timing mechanism using hydraulic pressure. In addition, high mechanical reliability can be obtained because a complicated hydraulic path and an on-off valve are not required.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a parts list for three rocker arms of the present invention. These components are responsible for opening and closing two valves on either the intake side or the exhaust side of one cylinder. FIG. 2 is a parts list for three rocker arms of the present invention. The viewing angle is different from FIG. These components are responsible for opening and closing two valves on either the intake side or the exhaust side of one cylinder. FIG. 3 is a side cutaway view of the present invention. When the engine is running at low speed. FIG. 4 is a side cutaway view of the present invention. When the engine is running at high speed. FIG. 5 is a side cutaway view of the present invention. FIG. 4 is a view seen from the opposite side to FIG. 3. When the engine is running at low speed. FIG. 6 is a side cutaway view of the present invention. FIG. 5 is a diagram viewed from the opposite side to FIG. 4. When the engine is running at high speed. FIG. 7 is an arrangement diagram of a rocker shaft (8) and a rocker arm group when the present invention is applied to a DOHC in-line four-cylinder engine. When the engine is running at low speed. FIG. 8 is an arrangement diagram of a rocker shaft (8) and a rocker arm group when the present invention is applied to a DOHC inline four-cylinder engine. When the engine is running at high speed. FIG. 9 is a side cutaway view of an engine showing one embodiment of the present invention. When the rocker arm is an external fulcrum method. [Description of Signs] 1, intake valve 2, exhaust valve 3, cam piece 4 with low-speed cam profile, low-speed rocker arm 5, high-speed rocker arm 6, cam piece 7 with high-speed cam profile, connection pin 8, rocker Shaft 9, gearshift passive 10, camshaft 11, gearshift shaft 12, gearshift gate 13, gearshift passive connector 14, gearshift shaft connector 15, gearshift passive connector gate 16 , Gate 17 for connecting body for shift shaft, spring 18 for holding down, push rod 19, electromagnetic actuator 20, return spring 21, cap 22 for rocker shaft, cap for shift shaft

Claims (1)

A four-stroke internal combustion engine having a DOHC mechanism,
In the type having two intake valves (1) and two exhaust valves (2) per cylinder, (a) driven by a cam piece (3) having a low speed cam profile and directly intake valve (1) or exhaust valve Pressing (2), the low-speed rocker arm (4) moves one intake valve (1) or one exhaust valve (2)
There is one by one. (B) Between the two low-speed rocker arms (4), 1
There are two high speed rocker arms (5), driven by a cam piece (6) having a high speed cam profile. One end of the high-speed rocker arm (5) is connected to the distal end of the low-speed rocker arm (4) by a connection pin (7). The other end is supported by a shifting passive (9) mounted on the rocker shaft (8). (C) A speed change passive body (9) exists on the rocker shaft (8), and supports one end of the high speed rocker arm (5). When the speed change passive body (9) is rotated by itself, the clearance between the high speed rocker arm (5) and the cam piece (6) having a high speed cam profile located immediately above it is reduced to zero or increased. Or (D) The cam piece (3) having a low-speed cam profile and the cam piece (6) having a high-speed cam profile exist on the same camshaft. The arrangement also corresponds to the position of the rocker arm to be pushed. (E) Inside the rocker shaft (8), there is a speed change shaft (11). This shifting shaft (11)
Has a speed change gate (12) on its surface. (F) A connection body (13) for a passive body for transmission is set so as to penetrate the rocker shaft (8) and the shaft (11) for transmission from the surface of the passive body (9) for transmission. One end of the connecting body (13) for the speed change passive body is fixed to the speed change passive body (9), and the other end is connected to the speed change gate (1) set on the surface of the speed change shaft (11).
2) is inserted. (G) A transmission shaft connector (14) is set so as to penetrate the transmission shaft (11) from the surface of the rocker shaft (8). (H) On the surface of the rocker shaft (8), in order not to prevent the transmission-purpose connecting body (13) from rotating together with the transmission-receiving body (9), the transmission-purpose connecting body is provided. The service gate (15) is set. (G) On the surface of the rocker shaft (8), in order to prevent the transmission shaft connecting body (14) from sliding along with the transmission shaft (11), the transmission shaft connecting body gate ( 16) is set. (G) When the engine is rotating at a low speed, no current flows through the electromagnetic actuator (19). As a result, the transmission shaft (11) is connected to the transmission shaft connector (14).
Of the transmission shaft connecting body gate (16) is located at the end of the bent portion. As a result, the high-speed rocker arm (5) supported by the speed-changing passive body (9) and pressed by the pressing spring (17) has a cam piece (6) having a high-speed cam profile immediately above it. It will be located so as to keep the clearance between them. As a result, the intake valve (1)
Alternatively, the exhaust valve (2) is pushed by a low speed rocker arm (4) driven by a cam piece (3) having a low speed cam profile, and opens and closes at a low speed valve timing. (L) When the engine is rotating at high speed, current flows through the electromagnetic actuator (19). As a result, the transmission shaft (11) is positioned such that the transmission shaft connector (14) is located at the end of the linear portion in the transmission shaft connector (16). As a result, the high-speed rocker arm (5) supported by the speed-change passive body (9) and pressed by the pressing spring (17) has a cam piece (6) having a high-speed cam profile immediately above it. ) Will be located such that the clearance between them is zero. As a result, the intake valve (1) or the exhaust valve (2) is directly pushed by the low-speed rocker arm (4), but is indirectly driven by the cam piece (6) having the high-speed cam profile. Under the control of the high-speed rocker arm (5), it opens and closes at a high-speed valve timing. A valve opening / closing mechanism for a four-cycle internal combustion engine having the above configuration.