JP5080403B2 - Variable valve mechanism - Google Patents

Description

  The present invention relates to a variable valve mechanism that changes a maximum lift amount of a valve in accordance with an operating state of an internal combustion engine.

  Among this type of variable valve mechanism, like the variable valve mechanism 90 of the conventional example (cited document 1) shown in FIGS. 8 and 9, the camshaft 91 provided rotatably and the camshaft. Rotating cam 92 (eccentric cam) provided on 91, ring arm 93 whose base end is externally inserted into rotating cam 92, swing member 94 externally inserted into camshaft 91, and upper portion of camshaft 91. And a control cam 97 (eccentric cam) provided on the control shaft 96, a central portion is extrapolated to the control cam 97, and one end portion is a tip portion of the ring arm 93. And a second lever 99 having one end pivotally attached to the other end of the first lever 98 and the other end pivotally attached to the swinging member 94. There is.

Therefore, when the camshaft 91 rotates at an arbitrary number of rotations, the variable valve mechanism 90 drives the valve 8 by swinging the swinging member 94 and rotates the control shaft 96 by an arbitrary angle. The maximum lift amount of the valve 8 driven by the swinging member 94 changes as the swinging member 94 rotates.
JP-A-11-324625

  However, in this conventional example, the mechanism (link) for transmitting the rotational force of the rotary cam 92 to the swing member 94 is composed of three members, the ring arm 93, the first lever 98, and the second lever 99. The (link) is long and complicated, and there is concern about the operation and reliability of the variable valve mechanism 90. As shown in FIG. 9, even if the maximum lift amount of the valve 8 is changed by the variable valve mechanism 90, the timing at which the maximum lift amount is reached hardly changes. However, in order to further improve the fuel consumption, it is preferable that the timing of the maximum lift amount changes simultaneously with the change of the maximum lift amount.

  In addition, since the control shaft 96 is located above the camshaft 91, the variable valve mechanism 90 becomes larger in the height direction. Furthermore, since there are many types of parts, the structure of the variable valve mechanism 90 becomes complicated.

  Therefore, the mechanism (link) for transmitting the rotational force of the rotating cam (eccentric cam) to the rocking member is made short and simple, and at the same time when the maximum lift amount is changed, the timing for reaching the maximum lift amount is also changed. The first object is to make the variable valve mechanism compact in the height direction, and the third object is to reduce the number of parts.

  In order to achieve the first object, a variable valve mechanism of the present invention is provided on a first camshaft and a second camshaft, which are provided side by side in parallel, and the first camshaft. And a first eccentric cam having a true circular cross section and having a center of the true circle eccentric from the axis of the first camshaft, and the second camshaft and rotating together with the second camshaft. A second eccentric cam having a true circular shape and a center of the true circle eccentric from the axis of the second camshaft, and a base end portion is extrapolated to the first eccentric cam so as to be relatively rotatable. A first ring arm and a second ring whose base end portion is externally attached to the second eccentric cam so as to be relatively rotatable, and whose distal end portion is pivotally attached to the distal end portion of the first ring arm. Extrapolated to the arm and the first camshaft for relative rotation The oscillating member and a power transmission in which one end is pivotally attached to the first ring arm or the second ring arm and the other end is pivotally attached to the oscillating member. By including a lever, when one camshaft of the first camshaft and the second camshaft rotates at an arbitrary rotational speed, the swinging member swings to drive the valve, When the other camshaft is rotated by an arbitrary angle, the swinging member is rotated to change the maximum lift amount of the valve driven by the swinging member, and at the same time, the one provided on the one camshaft One of the ring arms extrapolated to the eccentric cam also rotates to change the timing of reaching the maximum lift amount.

To achieve the second object, and at least part of the said part of the first cam shaft second camshaft, watching the length direction of the cylinder of the internal combustion engine as the height direction, the same height It is preferable that it is located in this position.

  In order to achieve the third object, the outer diameter of the first eccentric cam is equal to the outer diameter of the second eccentric cam, and the first ring arm and the second ring arm are A pair of identical members provided with a ring hole at the base end portion having an inner diameter equal to the outer diameter size of the first eccentric cam and the second eccentric cam, and having a shaft mounting hole at the distal end portion, The base end portion of each ring arm is extrapolated to the first eccentric cam or the second eccentric cam through the ring hole so as to be relatively rotatable, and the tip portions of both ring arms are connected to the shafts of both tip portions. It is preferable that the shaft is attached so as to be relatively rotatable by inserting a shaft-like shaft attachment member into the attachment hole.

  According to the present invention, since there are only two mechanisms (links) for transmitting the rotational force of the eccentric cam to the rocking member, the first or second ring arm and the power transmission lever, the mechanism (link) is short and simple. is there. Furthermore, with the above configuration, as described above, the maximum lift amount of the valve can be changed and the timing at which the maximum lift amount can be changed at the same time.

Variable valve mechanism 9 of the present invention, looking at the length direction of the cylinder of the internal combustion engine as the height direction, the first cam shaft 10 and at least a portion each other is provided in parallel side by side so as to be positioned at the same height The second camshaft 15 is provided on the first camshaft 10 and rotates together with the first camshaft 10. The cross-sectional shape is a perfect circle, and the center A of the true circle is the axis Ao of the first camshaft 10. The first eccentric cam 20 and the second cam shaft 15 which are eccentric from the second cam shaft 15 rotate with the second cam shaft 15. The cross-sectional shape is a perfect circle and the center B of the true circle is the center of the second cam shaft 15. A second eccentric cam 25 eccentric from the axial center Bo, a first ring arm 30 whose base end is extrapolated to be rotatable relative to the first eccentric cam 20, and a base end relative to the second eccentric cam 25. Rotating extrapolated tip The second ring arm 35 pivotally attached to the tip of the first ring arm 30, the swinging member 40 externally attached to the first camshaft 10, and one end of the first ring arm 30. A power transmission lever 45 is pivotally mounted on the one ring arm 30 or the second ring arm 35 so as to be relatively rotatable, and the other end is pivotally mounted on the swing member 40 so as to be relatively rotatable.

  Therefore, when one of the first camshaft 10 and the second camshaft 15 rotates at an arbitrary rotational speed, the swing member 40 swings to drive the valve 8 and the other camshaft is optional. And the maximum lift amount L of the valve 8 driven by the swinging member 40 is changed, and at the same time, one eccentric cam provided on one camshaft is rotated. The timing at which one of the extrapolated ring arms is rotated to reach the maximum lift amount L also changes.

  Here, the outer diameter of the first eccentric cam 20 and the outer diameter of the second eccentric cam 25 are equal. In addition, the first ring arm 30 and the second ring arm 35 have ring holes 31 and 36 at the base end portions, the inner diameters of which are equal to the outer diameters of the first eccentric cam 20 and the second eccentric cam 25. And a pair of identical members provided with shaft attachment holes 32 and 37 at the tip. And the base end part of each ring arm 30 and 35 is extrapolated to the 1st eccentric cam 20 or the 2nd eccentric cam 25 by the ring holes 31 and 36 so that relative rotation is possible. Further, the end portions of the ring arms 30 and 35 are axially attached so as to be relatively rotatable by inserting axial attachment members 39 into the axial attachment holes 32 and 37 of the both end portions. .

  1 to 6 are provided for each of the two intake valves 8, 8, and each variable valve mechanism is shown in FIG. 9 continuously changes the maximum lift amount L of the two valves 8 and 8. The variable valve mechanism 9 includes first and second camshafts 10 and 15 shown below, first and second eccentric cams 20 and 25, first and second ring arms 30 and 35, and a swing member. 40, a power transmission lever 45, and valve springs 50 and 50.

[Camshafts 10, 15]
First and second cam shafts 10 and 15, a common pair of camshaft plurality of variable valve mechanisms 9, 9 ... Both look the length direction of the cylinder of the internal combustion engine as the height direction Are arranged in parallel so as to be located at the same height. The first camshaft 10 is connected to a crankshaft (not shown) that rotates the first camshaft 10 at an arbitrary rotational speed, and the second camshaft 15 causes the second camshaft 15 to move at an arbitrary angle. It is connected to a control device (not shown) that rotates by the amount.

[Eccentric cams 20, 25]
The first eccentric cam 20 is an eccentric cam provided in the first camshaft 10 whose cross-sectional shape is a perfect circle and whose center A is eccentric from the axis Ao of the first camshaft 10. It rotates with one camshaft 10. Further, the second eccentric cam 25 is an eccentric cam in which the cross-sectional shape provided on the second camshaft 15 is a perfect circle and the center B of the true circle is eccentric from the axis Bo of the second camshaft 15. It rotates together with the second camshaft 15. The outer diameter of the first eccentric cam 20 and the outer diameter of the second eccentric cam 25 are equal.

[Ring arms 30, 35]
The first and second ring arms 30 and 35 are provided with ring holes 31 and 36, respectively, at the base end portions, the inner diameters of which are equal to the outer diameters of the first and second eccentric cams 20 and 25, respectively. It is a pair of identical members each having a shaft attachment hole 32, 37 in the part. The base end portion of the first ring arm 30 is extrapolated to the first eccentric cam 20 through the ring hole 31 so as to be relatively rotatable, and the base end portion of the second ring arm 35 is inserted into the ring hole 36. The second eccentric cam 25 is extrapolated to be relatively rotatable. Further, the distal end portion of the first ring arm 30 and the distal end portion of the second ring arm 35 are moved relative to each other by inserting a shaft-like shaft attachment member 39 into the shaft attachment holes 32 and 37 of both the end portions. It is pivotally mounted.

[Oscillating member 40]
The oscillating member 40 is externally attached to the first camshaft 10 so as to be relatively rotatable. The swing member 40 includes a pair of output noses 41, 41 that press the valves 8, 8, and a shaft attachment hole 42 for axially attaching the end of the power transmission lever 45 to the side surface of one of the output noses 41. It has.

[Power transmission lever 45]
The power transmission lever 45 includes shaft attachment holes 46 and 47 at one end and the other end, respectively. The one end portion of the power transmission lever 45 is inserted with the protruding portion of the shaft attachment member 39 in which the tip portions of the first and second ring arms 30 and 35 are axially attached to the shaft attachment hole 46 of the one end portion. Thus, the first and second ring arms 30 and 35 are pivotally attached to the tip portions thereof so as to be relatively rotatable. Further, the other end portion of the power transmission lever 45 is inserted into the shaft attachment hole 47 of the other end portion and the shaft attachment hole 42 of the swing member 40, thereby inserting the swing portion A shaft is attached to the side surface of the output nose 41 of the member 40 so as to be relatively rotatable.

[Valve springs 50, 50]
The valve springs 50 and 50 are a pair of return springs for closing the valves 8 and 8 by following the displacement of the pair of output noses 41 and 41 of the swinging member 40 in a direction away from the pair of valves 8 and 8. It is.

  Next, how the valves 8 and 8 are driven using the variable valve mechanism 9 of the first embodiment will be described. At this time, as shown in FIGS. 3 and 4, the first eccentric cam 20 rotates with the rotation of the first cam shaft 10, and the rotational force of the first ring arm 30, the power transmission lever 45, and the swinging member 40. By being transmitted in order, the swinging member 40 swings. The pair of valves 8 and 8 are driven by the swing of the swing member 40. At this time, the lift amount of the valves 8 and 8 is maximum (maximum lift amount L when the center A of the first eccentric cam 20 overlaps a predetermined maximum lift position P as shown in FIG. 4B. )

  Next, when the variable valve mechanism 9 of the first embodiment is used and the maximum lift amount L of the valves 8 and 8 is changed, {1} when the maximum lift amount decreases and {2} when the maximum lift amount increases. This will be described below.

{1} When the maximum lift amount decreases When the maximum lift amount decreases, as shown in FIG. 5A, the second camshaft 15 rotates in one circumferential direction, and the second camshaft 15 provided on the second camshaft 15 When the rotational force of the two eccentric cams 25 is transmitted in the order of the second ring arm 35, the power transmission lever 45, and the swinging member 40, the swinging member 40 rotates in the circumferential direction of the first camshaft 10. As a result, the maximum lift amount L of the valves 8, 8 decreases. At the same time, the rotational force of the second eccentric cam 25 is transmitted in the order of the second ring arm 35 and the first ring arm 30 so that the first ring arm 30 is opposite to the rotational direction of the first camshaft 10. Accordingly, the aforementioned maximum lift position P is shifted in the direction opposite to the rotation direction of the first camshaft 10, and the timing when the maximum lift amount L of the valves 8, 8 is reached is accelerated.

{2} When the maximum lift amount is increased When the maximum lift amount is increased, the second camshaft 15 rotates in the other circumferential direction as shown in FIG. When the rotational force of the two eccentric cams 25 is transmitted in the order of the second ring arm 35, the power transmission lever 45, and the swinging member 40, the swinging member 40 rotates in the circumferential direction of the first camshaft 10. As a result, the maximum lift amount L of the valves 8, 8 increases. At the same time, the rotational force of the second eccentric cam 25 is transmitted in the order of the second ring arm 35 and the first ring arm 30, so that the first ring arm 30 rotates in the rotational direction of the first camshaft 10. As a result, the aforementioned maximum lift position P shifts in the rotational direction of the first camshaft 10, and the timing at which the maximum lift amount L of the valves 8, 8 is reached is delayed.

  According to the first embodiment, the following effects {a} to {d} can be obtained.

{A} Since there are only two mechanisms (links) for transmitting the rotational force of the first eccentric cam 20 to the rocking member 40, the first ring arm 30 and the power transmission lever 45, the mechanism (link) is short and simple. is there. Therefore, it is highly rigid and can cope with high rotation.

{B} The timing at which the maximum lift amount L is reached when the maximum lift amount is decreased and when the maximum lift amount is increased, as shown in FIG. 6, is the rotation of the first ring arm 30 (the rotation of the maximum lift position P). Therefore, the timing of reaching the maximum lift amount L can be moved back and forth in conjunction with the increase / decrease of the maximum lift amount L. Therefore, fuel consumption can be improved.

{C} the first cam shaft 10 and the second cam shaft 15, look at the length direction of the cylinder of the internal combustion engine as the height direction, the same because they are located at a height, movable variable valve mechanism 9 is height- Compact in direction.

{D} Since the first ring arm 30 and the second ring arm 35 are a pair of identical members, the types of parts can be reduced.

  The variable valve mechanism 59 of the second embodiment shown in FIG. 7 is substantially the same as the variable valve mechanism 9 of the first embodiment, but the first camshaft 10 divides the first camshaft 10 by an arbitrary angle. The second camshaft 15 is connected to a crankshaft (not shown) that rotates the second camshaft 15 at an arbitrary number of rotations. It is different.

  A state when the valves 8 and 8 are driven using the variable valve mechanism 59 will be described. At this time, the second eccentric cam 25 rotates with the rotation of the second camshaft 15, and the rotational force is transmitted in the order of the second ring arm 35, the power transmission lever 45, and the swinging member 40, thereby the swinging member. 40 swings. The pair of valves 8 and 8 are driven by the swing of the swing member 40. At this time, the lift amount of the valves 8 and 8 becomes the maximum (maximum lift amount L) when the center B of the second eccentric cam 25 overlaps the predetermined maximum lift position Q.

  Next, when the variable valve mechanism 59 of the second embodiment is used to change the maximum lift amount L of the valves 8, 8, the changes in {1} maximum lift amount and {2} maximum lift amount increase. This will be described below.

{1} When the maximum lift amount is reduced When the maximum lift amount is reduced, the first camshaft 10 is rotated in one circumferential direction as shown in FIG. When the rotational force of the eccentric cam 20 is transmitted in the order of the first ring arm 30, the power transmission lever 45, and the swinging member 40, the swinging member 40 rotates in the circumferential direction of the first camshaft 10. As a result, the maximum lift amount L of the valves 8, 8 decreases. At the same time, the rotational force of the first eccentric cam 20 is transmitted in the order of the first ring arm 30 and the second ring arm 35 so that the second ring arm 35 is opposite to the rotation direction of the second camshaft 15. Accordingly, the maximum lift position Q is shifted in the direction opposite to the rotation direction of the second camshaft 15, and the timing at which the maximum lift amount L of the valves 8, 8 is reached is accelerated.

{2} When the maximum lift amount increases When the maximum lift amount increases, as shown in FIG. 7B, the first camshaft 10 rotates in the other circumferential direction, and the first camshaft 10 provided on the first camshaft 10 When the rotational force of the eccentric cam 20 is transmitted in the order of the first ring arm 30, the power transmission lever 45, and the swinging member 40, the swinging member 40 rotates in the circumferential direction of the first camshaft 10. As a result, the maximum lift amount L of the valves 8, 8 increases. At the same time, the rotational force of the first eccentric cam 20 is transmitted in the order of the first ring arm 30 and the second ring arm 35 so that the second ring arm 35 rotates in the rotational direction of the second camshaft 15. As a result, the aforementioned maximum lift position Q is shifted in the rotational direction of the second camshaft 15 and the timing of reaching the maximum lift amount L of the valves 8 and 8 is delayed.

  According to the second embodiment, contrary to the first embodiment, when the control device is connected to the first camshaft 10 and the crankshaft is connected to the second camshaft 15, the same effect as the first embodiment is achieved. Can be obtained. Further, in the case of the second embodiment, the rotation (rotation) of the first camshaft 10 on which the swing member 40 is extrapolated is smaller than that in the case of the first embodiment. And wear between the rocking member 40 can be reduced.

  The present invention is not limited to the configurations of the first and second embodiments, and can be modified and embodied without departing from the spirit of the invention. For example, depending on the mode of the internal combustion engine, the crankshaft In contrast to the present embodiment, the maximum lift amount L of the valves 8 and 8 is increased at the same time as changing the rotation direction of the first or second camshaft 10 or 15 connected to the opposite direction. The timing of reaching the amount L may be advanced so that the maximum lift amount L is decreased and at the same time the timing of reaching the maximum lift amount L is delayed. For example, the variable valve mechanisms 9 and 59 of the present invention may be provided for the exhaust valve.

It is a perspective view which shows the variable valve mechanism of Example 1 of this invention. The top view of the variable valve mechanism of the Example 1 is shown to (a), and side sectional drawing is a figure which shows to (b). The top view at the time of operation | movement of the variable valve mechanism of the Example 1 is shown to (a), and side sectional drawing is a figure which shows to (b). It is side surface sectional drawing which shows the mode at the time of the minimum lift amount at the time of operation | movement of the variable valve mechanism of the Example 1 in (a), and shows the mode at the time of the maximum lift amount in (b). It is side surface sectional drawing which shows the mode at the time of the maximum lift amount reduction | decrease of the variable valve mechanism of the Example 1 in (a), and shows the mode at the time of the maximum lift amount increase in (b). In the Example 1, it is a figure which shows the relationship between the rotation angle of an internal combustion engine, and the lift amount of a valve | bulb. It is side surface sectional drawing which shows the mode at the time of the maximum lift amount decrease of the variable valve mechanism of Example 2 of this invention to (a), and shows the mode at the time of the maximum lift amount increase in (b). It is side surface sectional drawing which shows the variable valve mechanism of a prior art example. In the prior art example, it is a figure which shows the relationship between the rotation angle of an internal combustion engine, and the lift amount of a valve | bulb.

Explanation of symbols

8 valve 9 variable valve mechanism 10 first camshaft 15 second camshaft 20 first eccentric cam 25 second eccentric cam 30 first ring arm 31 ring hole 32 shaft mounting hole 35 second ring arm 36 ring hole 37 shaft mounting Hole 39 Axle member 40 Oscillating member 45 Power transmission lever 59 Variable valve mechanism Ao Axis of first camshaft Bo Axis of second camshaft A Center of first eccentric cam B Center of second eccentric cam

Claims (3)

A first camshaft (10) and a second camshaft (15) provided side by side, and a first camshaft (15) provided on the first camshaft and rotating together with the first camshaft. A first eccentric cam (20) whose circular center (A) is eccentric from the axis (Ao) of the first camshaft, and a cross section provided on the second camshaft and rotating together with the second camshaft. A second eccentric cam (25) in which the shape is a perfect circle and the center (B) of the true circle is eccentric from the axis (Bo) of the second camshaft, and the base end portion rotates relative to the first eccentric cam. The first ring arm (30) extrapolated as possible and the base end portion are extrapolated to be rotatable relative to the second eccentric cam, and the distal end portion is rotatable relative to the distal end portion of the first ring arm. A second ring arm (35) pivotally attached to the first camshaft A swinging member (40) externally attached to the first ring arm or the second ring arm, and a second end attached to the swinging member. A power transmission lever (45) that is pivotally mounted so as to be relatively rotatable,
When one of the first camshaft (10) and the second camshaft (15) rotates at an arbitrary rotational speed, the swinging member (40) swings to drive the valve (8). When the other camshaft rotates by an arbitrary angle, the swinging member rotates to change the maximum lift amount (L) of the valve driven by the swinging member, and at the same time, the one camshaft A variable valve mechanism in which one ring arm that is extrapolated to one eccentric cam provided in the shaft also rotates to change the maximum lift amount. At least a portion of said first cam shaft (10) and a portion of the second cam shaft (15), look at the length direction of the cylinder of the internal combustion engine as the height direction, claim to be located at the same height The variable valve mechanism according to 1. The outer diameter of the first eccentric cam (20) is equal to the outer diameter of the second eccentric cam (25),
The first ring arm (30) and the second ring arm (35) are provided at the base end with ring holes (the inner diameters of which are equal to the outer diameters of the first eccentric cam and the second eccentric cam). 31 and 36), and a pair of identical members having a shaft attachment hole (32, 37) at the tip,
The base end portion of each ring arm is extrapolated to the first eccentric cam or the second eccentric cam in the ring hole so as to be relatively rotatable,
The tip portions of both ring arms are pivotally attached so as to be relatively rotatable by inserting a shaft-like shaft attachment member (39) into the shaft attachment holes of both tip portions. Variable valve mechanism.

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