JPS61226509A - Suction and exhaust timing adjusting equipment - Google Patents

Abstract

PURPOSE:To set a valve opening/closing time corresponding to operational conditions of an engine through simple structure by providing a rocking arm, which is driven by a suction and exhaust cam, to an adjusting link in a freely rotatable manner and driving the adjusting cam by means of a timing adjusting cam. CONSTITUTION:In order to open or close a suction and exhaust valve, a push rod 26 is operated via a roller 25 and a rocking arm 23, according to rotation of a valve opening/closing cam 21 provided to a cam shaft 20. A timing adjusting cam 22 is provided, neighboring to the cam 21. When the center 01 of an eccentric shaft 34, which rotates with the central shaft 0 as the central point, is rotated by a operation mechanism 35 in a direction by which the center 01 parts from the cam shaft 20, a roller 29 parts from the cam 22, while the roller 25 operates along the cam 21. When the operation mechanism 35 rotates the center 01 of the eccentric shaft 34 to the position of 01', the roller 29 touches the cam 22. Meanwhile, when the cam 22 rotates an adjusting link 27 via a roller 29, the rocking arm 23 moves toward the right in the figure. Thus, since the contact point of the cam 21 varies, the valve opening or closing timing can be changed.

Description

Detailed Description of the Invention "Field of Application in the Nitrogen Industry" The present invention relates to an intake/exhaust timing adjustment method that adjusts the opening/closing timing of intake valves and exhaust valves corresponding to high-load operation and low-load operation of an internal combustion engine. Regarding equipment.

``Prior art'' The opening angle and opening/closing timing of the intake valve and exhaust valve installed in an internal combustion engine are set to the optimum conditions within a certain range according to the engine's output and rotation speed, but during high-load operation , 11! As turbocharging increases with the increase in fuel output, the effective compression ratio is lowered to suppress explosion pressure, and the intake and exhaust valves are lowered to increase the scavenging effect and reduce heat load. It is necessary to increase the period C (overlap period) that is open at the same time. On the other hand, during low-load operation close to non-supercharging, it is necessary to shorten the above-mentioned overlap period in order to increase the effective compression ratio, increase the explosion pressure, and fully utilize the expansion pressure. In internal combustion engines whose valve closing timing is set to achieve the best performance, poor combustion occurs due to insufficient compression ratio during low-load operation, and exhaust gas enters the combustion chamber due to excessive p, t, and overlap periods. The air flows back to the intake side, causing various problems.

Therefore, in order to solve the problems that occur during low-load operation,
One idea was to switch the valve opening/closing timing to suit high-load and low-load operations. For example, as shown in FIG. 7, two rollers 2.3 are rotatably provided on the first link 1, and each roller 2.3 is interposed between a cam 4 and a tappet 5. , above whistle 1 link l
is swingably fixed to the tip of the second Q link 6 via the a-ra shaft of the 20th link 3, and the rear end of the second link 6 is attached to the lower end of the swing lever 8 by a pivot 7. On the other hand, the upper end of the swinging lever 8, which is swingably supported at the intermediate point 9, is connected to the piston rod 11 of the cylinder 10, and also to the rear g#A section of the first link 1. is inserted into a hook-shaped stopper 12 formed at the middle part of the second link 6, and a spring 13 is compressed and interposed between the rear end of the Iff link 1 and the second link 6. (See Japanese Patent Publication No. Sho 56-42725, in which a valve train is known). In this valve train, when the load is high, by interposing the two a-ra 2 and 3 between the cam 4 and the tappet 5), the tappet 5 moves as the cam 4 rotates. The valve is raised at the 20th line 3 and lowered at the 10th line 2, making the valve opening angle C (operating range) wider. By shortening and interposing only the 20th lug 3 between the cam 4 and the tappet 5, the tappet 5 is moved up and down by the 20th lug 3, and the opening angle of the valve is narrowed. The valve starts to open late, and the valve ends to close early.

"Problems to be Solved by the Invention" However, in the above conventional valve train, the cam 4
In order to change the number of rollers interposed between the
．． Stopper 12. There is a problem that the spring 13 and the like are required, the structure is complicated, and manufacturing and assembly is difficult. In addition, it is difficult to align the two rollers 2.3 and the lower curved surface of the tappet 5 in contact with each other, especially when switching between low-load operation and high-load operation. The problem is that it is difficult to carry out.

The present invention has been made in view of the above circumstances, and its purpose is to have a simple structure and to smoothly and reliably control the opening/closing timing of intake valves and exhaust valves during high-load operation and low-load operation. An object of the present invention is to provide an intake/exhaust timing adjustment device for an internal combustion engine that can be changed and easily switch the overlap period between each valve.

"Means for Solving the Problems" In order to achieve the above object, the present invention provides a camshaft with a valve drive cam for opening and closing an intake valve or a light exhaust valve and adjusting the opening/closing timing of the valve. A swing arm for transmitting the movement of the valve drive cam to the valve side is rotatably provided on the adjustment link, and a force adjustment link is rotatably provided on the support shaft. The support shaft is provided with a shaft moving mechanism that brings the adjustment link into contact with the timing adjustment cam.

"Function" In the intake/exhaust timing adjustment device of the present invention, the support shaft is moved by the shaft movement mechanism, and the adjustment link rotatably provided on the support shaft is brought into contact with the timing adjustment cam, or the timing adjustment cam The contact state between the swing arm rotatably provided on the Ql adjusting link and the valve drive cam is changed to switch the opening/closing timing of the intake valve or the exhaust valve.

"Embodiment" Hereinafter, one practical example of the present invention will be described based on FIGS. 1 to 6.

In the figure, 20 is a camshaft, and this camshaft 20 includes a valve drive cam 21 for opening and closing the intake valve or exhaust valve, and a timing adjustment cam 22 for adjusting the opening and closing timing of the intake valve by 11 m1.
and are attached along the axis of the camshaft 20, respectively. Above the valve drive cam 21, a swing arm 23 is provided with a tenth arm 25 rotatably supported by a pin 24 at the lower end of the swing arm 23 in contact with the valve drive cam 2. has been done. Furthermore, a lower end portion of a bushing rod 26 that transmits the movement of the valve drive cam 21 to the valve via the rocker arm is fitted into a recess 23a formed at the upper tip of the swing arm 23. The swing arm 23 is rotatably connected to the adjustment link 27 by a pin 28 by fitting its base end into a bifurcated bifurcated portion 27a of the adjustment link 27. Further, the timing adjustment cam 2 is provided on the other end side of the adjustment link 27.
2, a @20-ra 29 that rolls in contact with the adjustment cam 22 is rotatably supported by the bin 30, and the tip of the other end of the adjustment link 27 The 20th
- Spring 3 that presses the roller 29 toward the timing adjustment cam 22 side.
3 are connected.

Furthermore, a support shaft 34 is rotatably inserted into the intermediate portion of the IA4 alignment link 27, and this support shaft 34
An operating axis (f-axis moving mechanism) 35 is integrally connected to the end of the actuator in an eccentric manner. A projection 36 is formed on the support shaft 34, and a projection 36 is formed on the support shaft 34.
An arc-shaped recess 37 is formed at a position facing the projection 36 to limit the rotation angle of the adjustment link 27 within a certain range.

Further, the valve drive cam 21 has a cam protrusion formed in accordance with the valve opening angle (operation range) of the intake valve or exhaust valve during high-load operation, while the timing adjustment cam 22 has a For both intake valves and exhaust valves, the core cam 22 is used to retard the valve opening timing and advance the valve closing timing.
The above i@20-ra29 is applied to the valve opening timing and rme valve closing timing.
A convex portion and a concave portion are respectively formed in the vicinity of the contact position, and the settings are optimized for low load operation.

Furthermore, a fuel cam 41 for moving the fuel pump 40 is attached to the camshaft 20, and a fuel arm 42 is attached to the upper end of the fuel cam 41, and a fuel arm 42 is attached to the bottom of the tip of the fuel cam 41.
A fuel a-ra 44 rotatably supported by the fuel cam 41 is disposed in contact with the fuel cam 41, and a protrusion 42a formed at the top of the tip of the fuel a-ra 42 is connected to the fuel pump 40. The movable member 45 is brought into contact with the movable member 45, and when the protrusion 42a pushes up the movable member 45, the plunger of the fuel pump 40 is pushed up and fuel is supplied into the cylinder. Further, the fuel arm 42 has its base leakage portion rotatably connected to the bottom portion of the fuel link 46 in the shape of a letter 46, and the middle portion of the fuel link 46 has the above-mentioned Support shaft 3
A supporting roller 50 rotatably attached to the fixed arm 48 by a pin 49 is brought into contact with the upper part of the other end of the fuel link 46, and the fuel link 46 is rotatably inserted thereinto. The fuel link 46 is installed between the fixing member 52 and the mounting bin 51 attached to the lower part of the other end of the link 46.
a spring 53 that presses the upper part of the other end against the support roller 50;
The intake/exhaust timing configured as above, in which A! is connected: A! When performing high-load operation with an internal combustion engine equipped with one device.

In FIG. 1, the operating shaft 35 is rotated around its axis O.
Rotate F @ (9 clockwise turns). As a result, the support shaft 34, which is eccentrically connected to the operating shaft 35, rotates clockwise in FIG. 2 about the axis O of the operating shaft 35. Since the shaft center is at the high load position 01, the protrusion 36 of the support shaft 34 is connected to the adjustment link 27.
Lock it on one end side of the recess 37, and! ! ! Il adjustment link 2
Move the other end of 7 to the left. Therefore, adjustment link 2
7 is separated from the timing adjustment cam 22. This situation! 11, when the camshaft 20 rotates clockwise as shown in FIG. Based on this, the swinging arm 23 is attached to the bin '28.
The swinging arm 23 rotates up and down with
A bushing rod 26 fitted to the top of the tip moves up and down, and the intake valve A and the exhaust valve E are closed once at a predetermined time as shown by the solid line in FIG.

In addition, by turning the operating shaft 35 to the OFF side, the support shaft 34 is centered around the axis 0 of the operating shaft 35.
This is because the support shaft 34 rotates clockwise in FIG. 4, and the axis of the support shaft 34 reaches the high load position 0.

The fuel attached to the support shaft 34 and the link 46 move to the left with other parts being held between the support roller 50 of the fixed arm 48 and the spring 53. Therefore, the fuel link 46
Since the fuel arm 42 connected to the fuel arm 42 moves to the left, the fuel row 544 at the tip of the fuel arm 142 moves to the left along the top surface of the fuel cam 41, and is set at a position suitable for high-load operation.
lColle.

- In this state, when the camshaft 20 rotates clockwise as shown in FIG. 4, the fuel roller 44 rolls along the outer peripheral surface of the fuel cam 41.
Convex portion 41aR: Based on this, the fuel roller 44 is pushed upward, so that the fuel arm 42 rotates upward around the bottle 47, and the protrusion 428 on the upper tip of the fuel arm 42 causes the fuel pump 40 movable member 45
is pushed up. As a result, the plunger of the fuel pump 40 is pushed up, and fuel is supplied into the cylinder at a predetermined time suitable for high-load operation.

Next, when performing low load operation, in % Figure 1,
By rotating the operating shaft 35 five times to the ON side (counterclockwise), the support shaft 34, which is eccentrically connected to the operating shaft 35, rotates around the axis 0 of the operating shaft 35. Third
As shown in the figure, it rotates counterclockwise, and the axis of the support shaft 34 is at the low load position f! Since tO'1 is reached, the protrusion 36 of the support shaft 34 separates from the force on one end of the recess 37 of the adjustment link 27.
The adjustment link 27 is allowed to rotate within a certain angular range with respect to the support shaft 34. Therefore, the other end of the adjustment link 27 is rotated counterclockwise in FIG. In this pressed state, the camshaft 20 rotates clockwise, and when the convex portion of the valve drive cam 21 attached to the camshaft 20 approaches the first et-ra 25 at the tip of the swing arm 23, the camshaft 20 rotates clockwise. Then, the valve opening convex part of the timing adjustment force A22 adjusts the timing adjustment force A22.
Approach the 20th-ra 29 on the other end side of 7 (and #2
When the eI-ra 29 rides on the convex portion of the timing adjustment cam 22, the -adjustment link 27 rotates clockwise around the support shaft 34, so that the oscillator connected to one end of the 1iI11 link 27 The movable arm 23 moves to the right. As a result, the 10th lug 25 of the swing arm 23 moves toward the valve drive cam 21
Since it moves to the right along the outer circumferential surface of %@10-ra25
The timing at which the swinging arm 23 rides on the convex portion of the valve driving force A21 and the swinging arm 23 rotates one turn upward about the bottle 28 is delayed compared to the above-mentioned high-load operation. Therefore, the bushing V26 fitted to the upper end of the swing arm 23 moves upward, and the opening timing of the intake valve A and the exhaust valve E is delayed as shown by the dotted line in FIG.

Then, the camshaft 20 further rotates, and the 10th-ra 25
When approaches the end of the convex portion of the valve drive cam 21, the valve closing concave portion of the timing v4 adjustment cam 22 approaches the second a-ra 29 of the adjustment link 27 (7 and 2
When the 0-ra 29 is fitted into the valve closing recess of the timing adjustment cam 22, the adjustment link 27 rotates counterclockwise around the support shaft 34, so that it is connected to one end of the adjustment link 27. The swinging arm 23 that has been moved moves to the left.
As a result, the WTL 25 of the swing arm 23 comes off the convex part of the valve drive cam 21 and quickly reaches the region where the cam lift becomes 0, so that the swing arm 23 rotates downward about the bin 28. (Therefore, the bushing rod 26 fitted to the top of the tip of the swinging arm 23 moves downward, and the timing to close the intake valve A and the exhaust valve E is @
The speed increases as shown by the dotted line in Figure 6.

Further, by rotating the operating shaft 35 to the ON side, the support shaft 34 rotates around the axis O of the operating shaft 35, and the salt 5
This is because it rotates counterclockwise in the figure, and the axis of the support shaft 34 moves to the low load position O'1.

The fuel link 46 attached to the support shaft 34 moves to the right with its other end being held between the support roller 50 of the fixed arm 48 and the spring 53. Therefore, the fuel arm 42 connected to the fuel tank 46 moves to the right (from which the fuel roller 44 at the tip of the fuel arm 42 moves to the right along the upper surface of the fuel cam 41, and the axis of the C fuel roller 44 moves to the right). 0□ is rotated clockwise by an angle α around the camshaft 20) and is installed at a position suitable for low-load operation.
When the camshaft 20 rotates clockwise as shown in FIG. 5, the fuel roller 44 rolls along the outer circumferential surface of the fuel cam 41. As the fuel arm 42 is pushed upward, the fuel arm 42 rotates upward about the bottle 47, and the movable member 45 of the fuel pump 40 is pushed up by the protrusion 42a at the top of the tip of the fuel arm 42. At this time, the position of the fuel roller 44 is to the right compared to during high load operation.
Because of this movement, the timing at which the fuel roller 44 is pushed up by the protrusion 41a of the fuel cam 41 is delayed, which delays the timing at which the movable member 45 of the fuel pump 40 is pushed up by the protrusion 42a of the fuel arm 42. Therefore, by pushing up the plunger of the fuel pump 40 and delaying the timing at which fuel is supplied into the cylinder, conventionally, when fuel is injected at the same time as high-load operation, the pressure a[j is low. The problems of white smoke and poor combustion that occurred in the previous process are resolved, and a good combustion condition can be obtained.

In this way, by appropriately selecting the shapes of the valve drive cam 21 and the timing adjustment cam 22 and moving the position of the support shaft 34 to the operating shaft 35, the timing adjustment cam 2
2 and the second c1-ra 29 of the adjustment link 27, the uneven shape of the timing cam 22 causes the valve drive cam 21 to
Since the valve opening timing and valve closing timing can be arbitrarily advanced or delayed, the optimum valve opening/closing timing can be obtained for each of low load operation and high load operation. At the same time, the fuel injection timing m is also displayed on the support shaft 34.
The fuel link 46 for maintenance is attached, and as the position of the support shaft 34 is moved, the fuel arm 4 is connected via the fuel link 46.
Since the fuel pump 2 and the fuel roller 44 are moved left and right above the fuel cam 41, the fuel pump 4 is moved horizontally above the fuel cam 41.
The sudden start of zero can be delayed, the combustion condition inside the cylinder can be maintained in good condition, and no white smoke is produced.

"Effects of the Invention" As explained above, the present invention provides a valve drive cam for opening and closing the intake valve or the exhaust valve and a time OJ adjustment cam for adjusting the opening and closing timing of the mosquito valve, respectively, on the camshaft. A swing arm for transmitting the movement of the valve driving cam to the valve side is rotatably provided on the adjustment link, and the adjustment link is rotatably provided on the support shaft, and the adjustment link is provided on the support shaft at the same time. Since it is equipped with a shaft movement mechanism that makes contact with the adjustment cam, the shaft movement mechanism allows only the support shaft to be moved, and the 9V4S link rotatably provided on the support shaft to be brought into contact with the adjustment cam. By releasing the contact with the timing adjustment cam and changing the contact state between the swinging arm rotatably provided on the adjustment link and the valve drive cam, smooth and reliable high-load operation can be achieved. The valve opening timing and valve closing timing of the intake valve and exhaust valve can be changed during low-load operation, and the structure is simple and farming is easy.

[Brief Description of the Drawings] Figures 1 to 6 show one embodiment of the present invention, where Figure 1 is a perspective view, Figure 2 is a schematic explanatory diagram showing high load operation, and Figure 3 is a perspective view. The figure is a schematic explanatory diagram showing the time of low load operation, FIG. 4 is a schematic explanatory diagram of the fuel injection timing adjustment mechanism during high load operation,
Figure 5 shows fuel injection timing I during low load operation! FIG. 6 is a schematic explanatory diagram of the adjustment mechanism. FIG. 6 is a characteristic diagram showing the valve opening/closing timing of the intake valve A and exhaust valve E. FIG. 20...Camshaft, 21...Valve drive cam, 22...timing cam, 23...Swing arm, 27...・Adjustment link, 34...
...Support shaft, 35...Operating axis C-axis movement mechanism). Figure 1

Claims (1)

[Claims] In an intake/exhaust timing adjustment device for an internal combustion engine that opens and closes an intake valve or an exhaust valve according to the rotation of a camshaft having a cam, the camshaft is provided with a valve drive cam for opening and closing the valve, and a valve driving cam for opening and closing the valve. a timing adjustment cam for making the adjustment, a swinging arm that contacts the valve drive cam and transmits the movement of the valve drive cam to the valve side is rotatably provided on the adjustment link; A suction engine for an internal combustion engine, characterized in that a link is rotatably provided on the support shaft, and a shaft moving mechanism is provided on the support shaft to move the support shaft and bring the adjustment link into contact with the timing adjustment cam. Exhaust timing adjustment device.