JPH0550561B2 - - Google Patents

Description

Detailed Description of the Invention The present invention operates in conjunction with a cam that rotates in synchronization with the rotation of the crankshaft of an internal combustion engine to open and close an on-off valve, that is, an intake valve or an exhaust valve. The present invention relates to a valve operating system for an internal combustion engine that selectively changes the opening/closing mode of the valve according to the operating conditions.

In one form of an internal combustion engine including such a valve train, one cylinder of the engine has at least one of a plurality of intake valves and a plurality of exhaust valves, and in a low-speed or medium-speed rotation range, the same intake valve and exhaust valve By stopping some of the multiple valves that have the function and operating all the valves in the high-speed rotation range,
2. Description of the Related Art Internal combustion engines are known in which the output is improved over the entire operating range of the engine. Such internal combustion engines are equipped with a valve train with a shutdown function that selectively activates or deactivates only some of the valves depending on the operating state of the engine. A valve train that is satisfactory in this respect has not yet been obtained.

The present invention was made in view of such circumstances,
An object of the present invention is to provide a valve operating device for an internal combustion engine that is simple and compact in configuration, has high reliability, and is highly practical.

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

First, in FIG. 1, cylinder 2 of internal combustion engine 1
Inside, a piston 3 is slidably held by a cylinder sleeve 4 and housed in a reciprocating manner, and a cylinder head 5 mounted on the cylinder 2 has a plurality of intake passages 6 and exhaust passages 7. is formed. A plurality of on-off valves, that is, an intake valve 9 and an exhaust valve 10, are arranged at each opening end of the plurality of intake passages 6 and the exhaust passage 7 to the combustion chamber 8, respectively. At least one of the plurality of intake valves 9 and at least one of the plurality of exhaust valves 10 are selectively switched between the first opening/closing mode and the second opening/closing mode depending on the rotation speed of the engine 1. The intake valve 9 and the exhaust valve 10 configured in this manner are shown in the figure.

The intake valve 9 and the exhaust valve 10 are operated by the elastic force of the corresponding valve springs 11 and 12, respectively.
It is constantly biased in the direction of closing the openings of the intake passage 6 and the exhaust passage 7, that is, in the valve closing direction, and is pivotably supported by rocker arm shafts 13 and 14 as corresponding support parts. The rocker arms 15 and 16 have nuts 17 and 1 at the tip of each rocker arm 15 and 16.
When receiving an axial pressing force through adjustment screws 19 and 20 fixed by the valve springs 8, the valve springs 11 and 12 move in the axial direction against the elastic force of the valve springs 11 and 12 to open the valves.

Each rocker arm 15, 16 is connected to a corresponding cam 23, 24. The cams 23 and 24 each have resistance portions 25 and 26 formed by circumferential surfaces on a reference circle, and
A high portion 2 that bulges outward in the radial direction from the reference circle.
7 and 28, and these cams 23 and 24 are configured to rotate in synchronization with the rotation of the engine 1 around mutually different axes.

Each rocker arm 15, 16 is selectively connected to a corresponding cam follower 21, 2 according to the operating state of the engine 1 by a corresponding ratchet 54, 55 and a switching device 29, 30, which will be described later.
2 is connected. And these switching devices 29, 3
0 is in the operating state, the rocking motion of the cam followers 21, 22 driven by the cams 23, 24 is transmitted to the rocker arms 15, 16, and when the switching devices 29, 30 are in the non-actuating state, the cam followers 21, 22 are The rocking motion is not transmitted to the rocker arms 15,16.

Each switching device 29, 30 includes a trigger lever 33, 34 which is swingably supported by a corresponding pivot shaft 31, 32 and swings in conjunction with the swinging movement of each cam follower 21, 22, and a trigger lever 33, 34, which will be described later. drive rods 35 and 36 that are reciprocated in the axial direction by an actuator that
34, the drive rods 35, 36 can be locked in their operating or non-operating positions. The switching device 29 on the intake valve 9 side and the switching device 30 on the exhaust valve 10 side basically have the same configuration and function, so the following will be explained below.
The switching device 29 on the intake valve 9 side will be explained in more detail.

In FIGS. 2a, b, and c, the drive rod 35, which is reciprocated in the axial direction by the actuator 37, is constantly urged in the retracting direction (downward in FIG. 2a) by the elastic force of the return spring 38. When the actuator 37 is activated, the actuator 37 moves in the projecting direction (Fig. 2a).
(upward direction) and moves in the same direction against the elastic force of the return spring 38. Then, when the actuator 37 becomes inactive, the drive rod 35 is moved in the retracting direction again by the elastic force of the return spring 38.

A notch groove 39 for valve stopping and a notch groove 40 for valve actuation are sequentially formed in the drive rod 35 from its tip toward the base end on the actuator 37 side.
Further, on the proximal end side of the valve actuation notch groove 40, one bifurcated leg portion 43a of a substantially dogleg-shaped shift arm 42 serving as an interlocking member pivotally supported by a pivot shaft 41, 43b is formed with a notch engaging portion 44 that engages so as to create an axial play X. A joint 46 is rotatably provided between the other bifurcated legs 45a and 45b of the shift arm 42, and a shift plate 47 as a moving member is attached to a pivot 46a of the joint 46.
A shaft 48 rotatably supported at one end is inserted through the shaft 48, and a lock pin 49 engaged with a lock groove 46b formed in the peripheral wall of the joint 46 is inserted at the tip of the shaft 48 passing through the pivot hole 46a. is fitted.

Further, referring to FIG. 3, the rocker arm 15 includes a pair of arms 5 that are integrally molded in a substantially inverted U-shape and are connected at a predetermined distance from each other.
Consisting of 0.51, Rotzker armshaft 13
bearing parts 50a and 51a that are pivotally supported by the bearing parts 50a and 51a; and an engaging part 50b that engages with the top of at least one of the pair of intake valves 9a and 9b via at least one of the pair of adjustment screws 19a and 19b;
51b, and a curved sliding contact surface 15a formed on the inner upper surface of the connecting portion of each arm 50, 51, and is configured to operate or deactivate at least one of the pair of intake valves 9a, 9b. A pair of adjustment screws 19a, 19b are screwed into screw holes formed in each engagement 50b, 51b of arms 50, 51, and nuts 17 are screwed into each screw 19a, 19b.
It is fixed to each arm 50, 51 by a, 17b. The cam follower 21 has a pair of arms 5
It is pivotally supported by the rocker arm shaft 13 so as to be located in a space 15b between 0 and 51, and can freely move in and out of the rocker arm 15 in this space 15b.

The cam follower 21 includes a slipper part 21a that makes sliding contact with the cam surface of the cam 23 and a bearing part 21b that is pivotally supported by the rocker arm shaft 13. An open recess 53 having a generally gourd-shaped cross section is formed. As is clear from FIGS. 2b and 2c, the lower inner surface 53a of this recess 53 has approximately the same curvature as the sliding surface 15a of the rocker arm 15, and the slipper surface 53a of the cam follower 21
When the lower portion 25 of the cam 23 comes into contact with 1a, it is located on the extended surface of the sliding surface 15a of the rocker arm 15. A ratchet 54 serving as a swinging member having substantially the same width as the cam follower 21 is housed in the recess 53 of the cam follower 21 .

The ratchet 54 is fitted into the upper recess at an upper end 54a having approximately the same curvature as the upper recess of the recess 53, and as shown in FIG.
5 is in contact with the cam follower 21, the swinging lower end surface 54b protrudes from the recess 53 and engages the sliding surface 15a of the rocker arm 15, with the upper end 54a as the center of swing. 15, and a non-operating position where the lower end surface 54b is located within the recess 53 and does not transmit the rocking motion of the cam follower 21 to the rocker arm 15. A pin 56 is provided protruding from one side of the ratchet 54, and the aforementioned shaft plate 47 provided on one side of the cam follower 21 is attached to the pin 56, and the other end of the pin 56 has a circular arc shape centered on the axis of the rocker arm shaft 13. They are engaged through a long hole 47a formed in the. The shift plate 47 has an elongated hole 47b formed in the center so that the bearing part 21b of the cam follower 21
The cam follower 21 is supported movably in the radial direction of the bearing portion 21b, that is, in the longitudinal direction of the shift plate 47, by a portion protruding from the side surface of the cam follower 21 at. The protruding portion of the bearing portion 21b is formed so that the amount of protrusion is approximately equal to the thickness of the shift plate 47, so that the shift plate 47 is held between the side surface of the cam follower 21 and the inner surface of the bearing portion 50a of the rocker arm 15. It turns out.

As is particularly clear from FIGS. 2c and 3, the spring seat 1 formed on the rocker arm 15 side
5' and a spring seat 2 formed on the cam follower 21 side.
A spring 57 is interposed between 1' and 1'.
Due to the elastic force of this spring 57, the adjusting screw 1
Each end face of 9a, 19b is a constant intake valve 9a, 9b
The slipper part 21a that is in sliding contact with the cam 23 of the cam follower 21 is in contact with the top end face of at least one of the top parts of the cam 23 to the extent that no gap is created between the top end face of the cam follower 21 and the cam face of the cam 23 at all times. The rocker arm 15 and the cam follower 21 are biased in a direction in which they repel each other so that they come into contact with the cam surfaces to the extent that no friction occurs.

The trigger lever 33, one end of which is engaged with the engaging portion 21c of the cam follower 21, has its other end engaged while the slipper portion 21a of the cam follower 21 is in contact with the lower portion 25 of the cam 23 as the cam 23 rotates. Depending on the axial movement position of the drive rod 35, the valve stop notch groove 39 or the valve actuation notch groove 4
0 locks the drive rod 35 in the inoperative or activated position. Further, when the slipper part 21a of the cam follower 21 comes into contact with the high part 27 of the cam 23, one end of the trigger lever 33 is pressed by the engaging part 21c of the cam follower 21, and the trigger lever 33 is swung clockwise in FIG. 2c. ,
It disengages from the valve deactivation notch groove 39 or the valve actuation notch groove 40 with which it had been engaged until then, and the drive rod 35 is unlocked.

Below, Fig. 4 a, b, c to Fig. 8 a, b,
The switching operation of the switching device 29 will be explained according to FIG. First, in FIGS. 4a, b, and c, the actuator 37 is activated and the drive rod 35 is activated.
When the slipper part 21a of the cam follower 21 contacts the high part 27 of the cam 23 while receiving a pressing force in the direction in which the trigger lever 33 protrudes, the trigger lever 33 moves to the fourth position.
It swings clockwise in FIG. 3C to separate from the valve stop notch 39 and unlock the drive rod 35. As a result, the drive rod 35 first engages the notch engaging portion 44 and the bifurcated leg portion 43 of the shift arm 42.
a and 43b by the axial play X between them. The state in which the high portion 27 of the cam 23 is in contact with the slipper portion 21a of the cam follower 21 and the cam 23
As is clear from FIGS. 4b and 4c, the side surface of the ratchet 54 is in contact with the rocker arm 1 in the process of transitioning from the high part 27 to the low part 25.
Since the ratchet 54 cannot swing due to contact with the shift arm 42, the shift arm 42 does not swing yet.

When the cam 23 rotates further and the slipper portion 21a of the cam follower 21 is positioned so that the lower inner surface 53a of the recess 53 in the cam follower 21 of the cam 23 is positioned on the extended surface of the sliding surface 15a of the rocker arm 15.
Since the drive rod 35 further moves in the protruding direction from the states shown in FIGS. 4a, b, and c, the shift arm 42 swings counterclockwise in FIG. It is moved in the direction of the arrow in FIGS. 4a and 4b. As a result, the ratchet 54 swings around the upper end 54a from the state housed in the recess 53 of the cam follower 21 to the operating position, and the lower end surface 54a of FIG.
As shown in b and c, it engages with the sliding surface 15a of the rocker arm 15. At the same time, trigger lever 3
3 engages with the valve actuating notch 40 of the drive rod 35. Thereafter, as shown in FIGS. 6a, b, and c, as the cam 23 rotates, the trigger lever 33 intermittently engages with the valve actuation notch 40 to place the drive rod 35 in the actuation position. During this period, the rocker arm 15 rotates the cam follower 2 in accordance with the rotation of the cam 23 by the action of the ratchet 54.
1, the movement of the cam 23 is transmitted to at least one of the intake valves 9a and 9b via the cam follower 21, the ratchet 54, and the rocker arm 15, and the movement of the cam 23 is transmitted to at least one of the intake valves 9a and 9b.
At least one of a and 9b opens and closes in synchronization with the rotation of the engine 1. When only one of the intake valves 9a, 9b is driven, the other may be driven by a conventionally known drive mechanism.

Next, when the actuator 37 is in the non-operating state in the operating state shown in FIGS. However, as long as the slipper portion 21a of the cam follower 21 is in contact with the lower portion 25 of the cam 23, it is locked in the operating position by the action of the trigger lever 33 and cannot be moved. Eventually, as shown in FIGS. 7b and 7c, when the slipper part 21a of the cam follower 21 comes into contact with the high part 27 of the cam 23, the trigger lever 33 is pressed by the cam follower 21 and swings. As shown in FIGS. 7a and 7c, it is removed from the valve actuating notch 40 and the drive rod 35 is unlocked. In this state, the rocker arm 15 is connected to the valve spring 1.
1, the ratchet 5 engaged with the sliding surface 15a of the rocker arm 15
A strong frictional resistance is generated on the lower end surface 54b of the ratchet 54, and the ratchet 54 does not easily move from its operating position. Therefore, the drive rod 35, which is under the action of the return spring 38, first engages the notch engagement portion 4.
4 and the bifurcated legs 43a, 43b of the shift arm 42
It moves in the retraction direction by the axial play X between the two.

Next, as the cam 23 rotates, the contact position of the cam 23 with respect to the slipper part 21a of the cam follower 21 shifts from the high part 27 to the low part 25, and the cam follower 21 swings accordingly, thereby opening the valve. Since the reaction force of the spring 11 is weakened and the frictional resistance against the lower end surface 54b of the ratchet 54 is also reduced, the drive rod 35 is retracted by the elastic force of the return spring 38, and in conjunction with this, the shift arm 42 is moved to the second position. It swings clockwise in Fig. 7a. The swinging of the shift arm 42 causes the shift plate 47 to move in the direction of the arrows in FIGS. 7a and 7b, retracting the ratchet 54 from its operating position to the non-operating position shown in FIGS. 8a, b and c. At the same time, the trigger lever 33
As shown in Figures a and c, it engages with the notch 39 of the drive rod 35 for valve deactivation. Thereafter, as shown in FIGS. 2b and 2c, as the cam 23 rotates, the trigger lever 33 swings and engages intermittently with the valve stop notch 39 to disengage the drive rod 35. During the operation, the cam follower 21 moves in and out of the space 15b of the rocker arm 15, and the rocking motion of the cam follower 21 is not transmitted to the rocker arm 15, so that the intake valves 9a,
At least one of 9b is paused.

In the transition between the "operating state ← → resting state", the cam follower 21 is always swinging in accordance with the rotation of the cam 23, and the ratchet 45 provided on the cam follower 21 is also swinging with this swing. Ratchet 5 that swings the driving force of the shift arm 42
There is a concern that the information may not be communicated smoothly to 4. However, in the valve train according to the present invention, a pin 56 is provided protruding from one end of the ratchet 54, and an arc-shaped elongated hole 47a centered on the axis of the rocker arm shaft 13 is formed in the shift plate 47. The pin 56 and the elongated hole 47a enable the ratchet 54, which swings about the axis of the rocker arm shaft 13, to engage with the fixed shift plate 47, so that the driving force of the shift arm 42 is reduced. can be transmitted smoothly and reliably to the oscillating ratchet 54, and therefore the "operating state ← → resting state"
The transition can be made smoothly. Also,
The shift plate 47 is supported on one side of the cam follower 21 by a protruding portion of the bearing portion 21b so as to be movable only in the shift direction.
7 to the side of the cam follower 21 and the rocker arm 1
Since the shift plate 47 is clamped by the inner surface of the bearing portion 50a of No. 5 to form a slide direction support, there is no need to provide a bearing for the shift plate 47, a thrust backlash stopper, etc., and the mechanism can be simplified.

The valve train according to the present invention configured as described above can operate and deactivate two valves at the same time, so in a high-speed multi-cylinder internal combustion engine having two intake valves and two exhaust valves per cylinder, By being used to drive two valves in the same cylinder, the engine can be made into a cylinder deactivation type engine in which the operation of only a predetermined cylinder is suspended. Further, in the case where at least one of the intake valve and the exhaust valve is two or more valves, it is also possible to apply the valve train of the present invention to only a single valve, and furthermore, it is possible to apply the valve train of the present invention to at least one of the intake valve and the exhaust valve. In the case where one valve has three or more valves, it is also possible to apply the valve train according to the present invention to only two valves.

Further, in the above embodiment, the case where the opening/closing mode of the intake valve 9a or 9b is in the operating state and the resting state has been described, but the structure is not limited to such a structure. It goes without saying that the configuration of the present invention is also applicable to other open and closed states, such as making the lengths of open time different.

As described above, the rocker arm 15 is composed of a pair of arms 50 and 51 that are spaced a predetermined distance from each other and connected at their swinging ends to form a substantially U-shape. The structure is such that a pair of on-off valves can be simultaneously driven by the above. in this way,
When driving a pair of on-off valves, only one rocker arm is shared by both on-off valves, and it is formed into a U-shape, so the support span (width) of the rocker arm is large. The rocking motion is performed stably, and problems such as uneven load and uneven wear on the bearing portion or the slipper surface do not occur.

As explained above, according to the first configuration characterized by the present invention, the cam follower and the rocker arm, which can swing independently from each other, are swingably supported by a common support part (rocker arm shaft). A swinging member is swingably housed in a recess formed at the swinging end of the cam follower, and the swinging member is rocked between an operating position and a non-operating position depending on the operating state of the engine. When the swinging member is in the operating position, the swinging motion of the cam follower is transmitted to the rocker arm, and when the swinging member is in the non-operating position, the swinging motion of the cam follower is not transmitted to the rocker arm, so the structure of the mechanism is simple and simple. Compact, highly reliable, and highly practical. Furthermore, since only compressive loads act on the swinging member that controls the transmission of the swinging motion of the cam follower to the rocker arm, the mechanism has excellent durability for use in internal combustion engines. A valve train with a stop function can be obtained.

In addition, in the second feature of the valve operating system for an internal combustion engine according to the present invention, one rocker arm is connected at one end with a predetermined distance apart from each other, and is swingable at the other end by a support part. It is formed in a U-shape consisting of a pair of supported arms,
By swinging the rocker arm, a pair of on-off valves are driven simultaneously.

In this way, when driving a pair of on-off valves,
Due to the configuration in which only one Locker arm is shared by both opening/closing valves and it is formed in a U-shape,
The support span (width) of the rocker arm is increased, its rocking motion is stabilized, and there is no concern that problems such as uneven load and uneven wear will occur on the bearing portion or the slipper surface.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of a main part of an internal combustion engine equipped with a valve train with a valve shutting function according to the present invention, FIG. 2 a is a cross-sectional view of a main part of a valve train in a valve rest state, and FIG. 2 b
is a sectional view taken along the line A-A in Figure 2a, Figure 2c is a sectional view taken along the line B-B in Figure 2a, Figure 3 is an exploded perspective view of the main parts of the valve train, and Figure 4a is the valve. 4b is a sectional view taken along the line A-A in FIG. 4a, and FIG. 4c is a sectional view taken along line B-B in FIG. 4a. 5a is a sectional view of the main part of the valve train when switching from the valve resting state to the operating state is completed; FIG. 5b is a sectional view taken along the line A-A in FIG. 5a; FIG. 5c is a sectional view taken along the line B-B in Figure 5a,
Figure a is a cross-sectional view of the main parts of the valve train in the valve operating state, Figure 6b is a cross-sectional view taken along the line A--A in Figure 6a, and Figure 6
Figure c is a sectional view taken along the line B-B in Figure 6a, Figure 7a is a sectional view of the main parts of the valve train at the time when the valve starts switching from the operating state to the rest state, and Figure 7b is the diagram shown in Figure 7. A of a
-A sectional view, FIG. 7c is a sectional view taken along the line B-B of FIG. 7a, FIG. Figure 8b is a sectional view taken along the line A-A of Figure 8a, and Figure 8c is a cross-sectional view of Figure 8a.
It is a sectional view taken along the line BB in Figure a. Explanation of symbols of main parts, 1...Internal combustion engine, 9,
9a, 9b...Intake valve, 10...Exhaust valve, 13,
14...Rotzker armshaft, 15, 16...
...Lotsuker arm, 21,22...Cam follower, 23,24...Cam, 29,30...Switching device, 33,34...Trigger lever, 35,36
...Drive rod, 42...Shift arm, 47...
...Shift plate, 54...Ratchet (swinging member).

Claims (1)

[Scope of Claims] 1. An on-off valve is driven to open and close in conjunction with a cam that rotates in synchronization with the rotation of the crankshaft of an internal combustion engine, and the on-off valve is selectively opened and closed according to the operating state of the engine. It is a valve operating system for an internal combustion engine that changes the temperature of the engine, and consists of a pair of arms that are connected at one end at a predetermined distance from each other and are swingably supported by a support part at the other end. a rocker arm that drives the opening/closing valve at one end of the pair of arms, and a rocker arm that is swingably supported by the support section between the pair of arms independently of the rocker arm, and that rotates in response to rotation of the cam. a swinging cam follower; a swinging member swingably accommodated in a recess formed at a swinging end of the cam follower; an operating position in which the rocker arm protrudes from the recess and engages with the rocker arm, thereby transmitting the rocking motion of the cam follower to the rocker arm; and a non-operating position located within the recess in which the rocker motion of the cam follower is not transmitted to the rocker arm. A valve operating device for an internal combustion engine, comprising: a switching device that swings between. 2. The switching device includes a moving member supported on one side of the cam follower by a bearing portion of the cam follower so as to be movable in the radial direction of the bearing portion, and one end of which is engaged with the other end of the swinging member; The internal combustion engine according to claim 1, further comprising a drive mechanism that applies a driving force to the other end of the movable member so as to position the other end of the swinging member at the operating position or the non-operating position. Valve gear for use. 3. The drive mechanism includes a drive rod that has two grooves corresponding to the operating position and non-operating position of the swinging member and is movable in the axial direction between the operating position and the non-operating position; an interlocking member that drives the moving member in conjunction with the moving movement of the rod; and an interlocking member that swings in conjunction with the swinging movement of the cam follower and intermittently engages with one of the two grooves to drive the driving rod. 3. A valve train for an internal combustion engine according to claim 2, further comprising a trigger lever that is locked in an operating position or a non-operating position. 4. An internal combustion engine that opens and closes a pair of on-off valves in conjunction with a cam that rotates in synchronization with the rotation of the crankshaft of the internal combustion engine, and selectively changes the opening and closing mode of the on-off valves according to the operating state of the engine. This is a valve train for an engine, and consists of a pair of arms connected at one end at a predetermined distance from each other and swingably supported by a support part at the other end. A rocker arm that drives the pair of on-off valves at a connecting portion on one end of the arm, and a rocker arm that is swingably supported by the support portion between the pair of arms independently of the rocker arm and that is supported by the rotation of the cam. A cam follower that swings according to the operating state of the engine, and switching between an operating state in which the swinging motion of the cam follower is transmitted to the rocker arm and a non-operating state in which the swinging motion of the cam follower is not transmitted to the rocker arm depending on the operating state of the engine. A valve operating device for an internal combustion engine, characterized by comprising: