JP5436103B2 - Variable valve mechanism - Google Patents

Description

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

  Among the variable valve mechanisms, like the conventional variable valve mechanism 90 shown in FIG. 6, a drive cam 91 for supplying a driving force and the driving force to the valve 6 are transmitted to the valve 6. A link mechanism in which a plurality of swing levers 92 to 95 that are opened and closed are connected in turn so as to be relatively rotatable at each joint, and a variable mechanism 97 that changes the opening and closing amount of the valve 6 by displacing the link mechanism. Some are composed.

  JP-A-11-324625

  However, in the variable valve mechanism 90 of the conventional example described above, the opening / closing amount of the valve 6 may deviate from the desired opening / closing amount due to the displacement of the dimensions of the swing levers 92 to 95, leading to a decrease in engine performance. is there.

  Accordingly, it is an object of the present invention to enable adjustment even if the opening / closing amount of the valve deviates from a desired opening / closing amount due to a difference in the size of each swing lever.

In order to achieve the above object, a variable valve mechanism according to the present invention includes a driving cam for supplying a driving force, and a plurality of swing levers that transmit the driving force to the valve to open and close the valve. A variable valve mechanism comprising: a link mechanism that is connected so as to be relatively rotatable at a joint; and a variable mechanism that changes an opening / closing amount of the valve by displacing the link mechanism. Any one of the swing levers is provided with a length adjusting mechanism for adjusting the length of the one swing lever, and the length of the valve is adjusted by adjusting the length with the length adjusting mechanism. The length adjustment mechanism is configured to be able to adjust the opening / closing amount, and the length adjusting mechanism is inserted in a replaceable manner between the one swing lever divided into two members in the length direction and the two members. Insert the spacer between the spacers. In this state, the two members are connected to each other so as to be disengageable, and the length of the one swing lever can be adjusted by replacing the spacer with a spacer having a different thickness. One of the two members is connected to the other member by the connecting member, and extends from the connected portion in the width direction of the one swing lever, A connecting shaft connected to another swinging lever adjacent to one member so as to be relatively rotatable at one of the joints, and the connected portion is connected to the connecting shaft more than the connecting shaft. It is large in the radial direction, and the connected portion is provided with a flat contact surface that contacts the spacer .

  Furthermore, the one member and the other swing lever are not particularly limited, but the connection shaft is provided one on each side in the width direction of the one swing lever of the coupled portion, The other swing lever is preferably divided into a member connected to one of the two connecting shafts and a member connected to the other. This is because if the adjacent swing levers are divided and formed in this way, it is possible to easily assemble even when the connected parts are larger in the radial direction than the connecting shafts on both sides as described above.

According to the present invention, as described above, a length adjustment mechanism is provided for at least one of the swing levers, and the length of the swing lever is adjusted by the length adjustment mechanism, thereby opening and closing the valve. The amount can be adjusted. The coupled portion is formed larger in the radial direction of the connecting shaft than the connecting shaft, and the coupled portion is provided with a planar contact surface that contacts the spacer. The contact surface can be formed without reducing the section modulus (strength against bending) of one member.

It is a perspective view which shows the variable valve mechanism of the Example of this invention. It is a disassembled perspective view which shows the variable valve mechanism of the Example. The variable valve mechanism of the Example is shown to (a), and the mode at the time of the operation | movement is a side view which shows to (b). It is a side view which shows the mode when the amount of opening and closing of the valve by the variable valve mechanism of the same embodiment is decreased by the variable mechanism is shown in (a), and the mode when it is increased is shown in (b). It is a side view which shows the mode when the opening / closing amount of the valve by the variable valve mechanism of the embodiment is adjusted to decrease by the length adjusting mechanism, and shows the mode when the increase is adjusted, as shown in (b). . It is a side view which shows the variable valve mechanism of a prior art example.

  The variable valve mechanism 7 of this embodiment shown in FIGS. 1 to 5 is provided for two intake or exhaust valves 6 and 6 provided for the same cylinder. The opening / closing amount L of the valves 6 and 6 is continuously changed. The variable valve mechanism 7 includes a drive cam 8, first to fifth swing levers 10, 20, 30, 40, 50, 50, rocker arms 60, 60, and a variable mechanism 70. It is comprised including. Here, each of the first to fifth swing levers 10, 20, 30, 40, 50, 50 extends in each direction orthogonal to the left-right direction and swings within each plane orthogonal to the left-right direction. It is possible to move. The first to fifth swing levers 10, 20, 30, 40, 50, 50 transmit a driving force of the driving cam 8 to the rocker arms 60, 60 to open and close the valves 6, 6. It is composed.

[Drive cam 8]
The driving cam 8 is provided on a camshaft 9 extending in the left-right direction, and rotates with the rotation of the camshaft 9. The drive cam 8 has a true circular cross-sectional shape, and the center A of the true circle is eccentric from the axis Ao of the camshaft 9. The camshaft 9 is a common shaft for the plurality of variable valve mechanisms 7, 7... And rotates according to the rotation of the internal combustion engine.

[First swing lever 10]
The first swing lever 10 includes a ring-shaped ring portion 11 at a rear end portion thereof, and is externally fitted to the driving cam 8 at the ring portion 11 so as to be relatively rotatable. Further, a connected hole (not shown) for connecting to the rear end portion of the second swing lever 20 is provided through the tip portion.

[Second swing lever 20]
The second swing lever 20 includes a ring-shaped ring portion (not shown) in the middle in the length direction, and is fitted on a support shaft 72 (described later) at the ring portion. It is supported so as to be capable of relative rotation. Further, a connection hole 22 is provided at the rear end portion, and a single connection pin 23 is inserted into the connection hole 22 and a connection hole (not shown) at the tip of the first swing lever 10. The rear end portion of the second swing lever 20 is connected to the front end portion of the first swing lever 10 so as to be relatively rotatable. Further, a connected hole 25 for connecting to the rear end portion of the third swing lever is provided at the front end portion of the second swing lever 20.

[Third swing lever 30]
The third swing lever 30 is divided into a left lever member 30L and a right lever member 30R in the left-right direction. A connecting shaft 33 extending rightward is projected from the right side surface of the rear end portion of the lever left side member 30L, and a connecting shaft 33 extending leftward is projected from the left side surface of the rear end portion of the lever right member 30R. Has been. The connecting shafts 33 and 33 are inserted into the connected holes 25 at the front end of the second swing lever 20 from the left and right sides, respectively, so that the rear end portion of the third swing lever 30 is moved into the second swing. The lever 20 is connected to the tip of the lever 20 so as to be relatively rotatable. Further, through-holes 35, 35 for connecting to the rear end portion of the fourth swing lever 40 are respectively penetrated at the front end portions of the lever left side member 30L and the lever right side member 30R.

[Fourth swing lever 40]
The fourth swing lever 40 is divided into a lever rear side member 41 and a lever front side member 44 in the length direction. The fourth swing lever 40 is provided with a length adjustment mechanism 47 for adjusting the length thereof.

  The lever rear member 41 constitutes a rear end portion of the fourth swing lever 40. The lever rear side member 41 includes a connected portion 42 connected to the lever tip side member 44 and two left and right connecting shafts 43 extending leftward from the left side and rightward from the right side of the connected portion 42. , 43. The to-be-connected part 42 is longer than the connection shafts 43, 43 in the radial direction of the connection shafts 43, 43 from the cylindrical state formed on the both sides in the length direction of the fourth swing lever 40. The part of is made into a shape cut out in a planar shape. The plane of the connected portion 42 on the lever tip side member 44 side constitutes a contact surface 42b that contacts a spacer 48 described later. Further, a bolt through hole 42 a for connecting the connected portion 42 to the lever tip side member 44 is provided in the connected portion 42 in the length direction of the fourth swing lever 40. Further, in the lever rear member 41, the left connecting shaft 43 is inserted into the connected hole 35 at the tip of the lever left member 30L of the third swinging lever 30, and the right connecting shaft 43 is connected to the third swinging member 30L. By being inserted into the connected hole 35 at the tip of the lever right side member 30 </ b> R of the moving lever 30, it is connected to the tip of the third swing lever 30 so as to be relatively rotatable. One connecting shaft 43 of the lever rear member 41 is also connected to the tip of a variable lever 73 (to be described later) of the variable mechanism 70, so that the displacement direction of the connecting shaft 43 is one circumferential direction. Is regulated.

  The lever tip side member 44 constitutes a portion other than the rear end portion of the fourth swing lever 40. The lever front side member 44 has a rear end portion that is in contact with the spacer 48 and a female screw-like bolt hole 44 a extending in the length direction of the fourth swing lever 40 for connecting the lever rear side member 41. And a projection 44c, 44c for preventing the spacer 48 from shifting. Further, a to-be-connected hole (not shown) for connecting to the fifth swing levers 50, 50 is provided at the tip of the lever tip side member 44.

  The length adjusting mechanism 47 includes the lever rear side member 41 and the lever front side member 44 described above, a spacer 48 inserted in an interchangeable manner between the lever rear side member 41 and the lever front side member 44, It includes a bolt 49 as a connecting member in which the lever rear side member 41 and the lever front side member 44 are connected so as to be disengageable with the spacer 48 inserted therebetween. Here, the spacer 48 is a plate-like member (shim), and a notch 48a is provided from one side to the center. The bolt 49 is screwed into the bolt hole 44 a of the lever tip side member 44 in a state where the bolt through hole 42 a of the lever rear side member 41 and the notch 48 a of the spacer 48 are inserted.

[Fifth swing lever 50]
The fifth swing levers 50 and 50 are a pair of levers provided for each of the valves 6 and 6. The fifth swing levers 50, 50 are provided with ring portions 51, 51 at their rear ends, respectively, and are fitted to the support shaft 72 by the ring portions 51, 51, respectively. It is supported movably. Further, the fifth swing levers 50, 50 are provided with connected holes 52, 52 in the middle portion in the length direction, and the connected holes 52, 52 and the connected holes at the tip of the fourth swing lever 40. (Not shown), when one connecting pin 53 is inserted, the middle portion in the longitudinal direction of the fifth rocking levers 50 and 50 is rotated relative to the tip of the fourth rocking lever 40. Connected as possible. Further, pressing surfaces 55 and 55 for pressing the pair of rocker arms 60 and 60 are formed on the lower surfaces of the distal end portions of the fifth swing levers 50 and 50.

[Rocker arms 60, 60]
One rocker arm 60, 60 is provided for each valve 6, 6. Each rocker arm 60 extends in one direction orthogonal to the left-right direction, and its rear end is supported by a lash adjuster 67 so as to be able to swing, and is a roller that abuts against the pressing surface 55 of the fifth swing lever 50 at the middle in the length direction. 63, and a pressing surface 65 for pressing the stem end of the valve 6 is provided at the tip.

  Further, the valves 6 and 6 are provided with valve springs for closing the valves 6 and 6 by following the displacement of the pressing surfaces 65 and 65 of the rocker arms 60 and 60 in the direction away from the stem ends of the valves 6 and 6. (Not shown) is attached.

  Therefore, when the camshaft 9 is rotated, as shown in FIG. 3 (b), the driving cam 8 is rotated with the rotation of the camshaft 9, and the driving force thereof is the first swing lever 10 and the second swing lever. 20, the third rocking lever 30, the fourth rocking lever 40, the pair of fifth rocking levers 50 and 50, and the pair of rocker arms 60 and 60 are transmitted in this order, so that the pair of rocker arms 60 and 60 rocks. The pair of rocker arms 60, 60 opens and closes the pair of valves 6, 6 with a constant opening / closing amount L.

[Variable mechanism 70]
The variable mechanism 70 is a mechanism that changes the opening / closing amounts of the valves 6 and 6 by displacing the connection shaft 43 of the lever rear side member 41 of the fourth swing lever 40. The variable mechanism 70 includes a variable cam 71 and a variable lever 73 shown below.

  The variable cam 71 is provided on a support shaft 72 that supports the second rocking lever 20 and the fifth rocking levers 50 and 50 so as to be relatively rotatable, and rotates with the rotation of the support shaft 72. The cross-sectional shape of the variable cam 71 is a perfect circle, and the center B of the perfect circle is eccentric from the axis Bo of the support shaft 72. The support shaft 72 is rotationally driven by a rotational device (not shown).

  The variable lever 73 extends in one direction orthogonal to the left-right direction, and includes a ring-shaped ring portion 74 at the rear end. The ring part 74 is rotatably fitted to the variable cam 71. Further, the variable lever 73 has a connection hole 75 penetrating at the tip thereof, and one connection shaft 43 of the lever rear side member 41 of the fourth swing lever 40 is inserted into the connection hole 75. By being inserted, the front end portion of the variable lever 73 is pivotally connected to the rear end portion of the fourth swing lever 40. Further, a stopper 76 for preventing the variable lever 73 from coming off the connecting shaft 43 is attached to the connecting shaft 43 of the fourth swing lever 40.

  Therefore, as shown in FIG. 4A, when the support shaft 72 is driven by a rotation device (not shown) and rotated in one circumferential direction, the variable cam is rotated along with the rotation of the support shaft 72. 71 is rotated, and the driving force is transmitted in the order of the fourth swing lever 40 and the pair of fifth swing levers 50, 50, so that the pair of fifth swing levers 50, 50 are connected to the support shaft 72. While the shaft Bo is swung around the shaft Bo, the swing range is entirely shifted in one circumferential direction of the shaft Bo, and the opening / closing amount L of the valves 6 and 6 is reduced.

  Further, as shown in FIG. 4B, when the support shaft 72 is driven by a rotation device (not shown) and rotates in the other circumferential direction, the variable cam is rotated along with the rotation of the support shaft 72. 71 is rotated, and the driving force is transmitted in the order of the fourth swing lever 40 and the pair of fifth swing levers 50, 50, so that the pair of fifth swing levers 50, 50 are connected to the support shaft 72. While the shaft Bo is swung around the shaft Bo, the swing range is entirely shifted in the other circumferential direction of the shaft Bo, and the opening / closing amount L of the valves 6 and 6 is increased.

  Next, the state of adjusting the opening / closing amount L (and timing) of the valves 6 and 6 by using the length adjusting mechanism 47 is increased at the time of decreasing adjustment for adjusting the opening / closing amount L to be decreased. This will be described below separately for the time of increase adjustment.

{During adjustment}
As shown in FIG. 5 (a), the bolts 49 are loosened and the spacers 48 are pulled out. Instead, the spacers 48P thinner than the spacers 48 are inserted and the bolts 49 are tightened. The spacer 48P is replaced with a thinner spacer 48P. Accordingly, the length of the fourth rocking lever 40 is slightly shortened, and accordingly, the pair of fifth rocking levers 50 and 50 are slightly in one rotating direction around the axis Bo of the support shaft 72. The opening / closing amount L of the valves 6 and 6 slightly decreases.

{Increase adjustment}
As shown in FIG. 5 (b), the bolts 49 are loosened and the spacers 48 are pulled out. Instead, the spacers 48Q that are thicker than the spacers 48 are inserted, and the bolts 49 are tightened. The spacer 48Q is replaced with a thicker spacer 48Q. Accordingly, the length of the fourth rocking lever 40 is slightly increased, and accordingly, the pair of fifth rocking levers 50 and 50 are slightly moved in the other rotation direction around the axis Bo of the support shaft 72. The opening / closing amount L of the valves 6 and 6 slightly increases.

  Note that the rank intervals and the number of ranks of the spacers 48P, 48, and 48Q can be arbitrarily set, and the adjustment accuracy and the adjustable range can be arbitrarily determined by changing the rank interval and the number of ranks.

  According to the present embodiment, as described above, the spacer 48 inserted between the lever rear side member 41 and the lever tip side member 44 of the fourth swing lever is replaced with spacers 48P and 48Q having different thicknesses. Thus, the opening / closing amount (and timing) of the valves 6 and 6 can be adjusted. Therefore, more accurate valve timing can be synchronized, which contributes to improvement in engine performance. Further, the dimensional accuracy of each component such as the swing levers 10, 20, 30, 40, 50 can be relaxed, and the ease of manufacturing is improved.

  Further, the connected portion 42 of the lever rear member 41 is formed to be larger in the radial direction than the connecting shafts 43 and 43 on both sides thereof, and a flat contact surface 42b that contacts the spacer 48 on the connected portion 42. By providing this, it is possible to secure a large contact area with respect to the spacer 48 without reducing the section modulus (strength against bending) of the lever rear member 41. Further, the problem of assembling that occurs when the lever rear side member 41 has such a thick middle portion is that the third rocking lever 30 is connected to the lever left side member 30L and the lever in the left-right direction as described above. This can be solved by dividing the right member 30R. Thus, by devising the shape of the lever rear member 41 of the fourth swing lever 40 and the shape of the third swing lever 30 in this way, the strength of the main part of the length adjusting mechanism 47 is reduced to a small space. Can be put together.

  In addition, this invention is not limited to the structure of the said Example, In the range which does not deviate from the meaning of invention, it can also change and actualize.

6 Valve 7 Variable valve mechanism 8 Drive cam 10 First swing lever 20 Second swing lever 30 Third swing lever (other swing lever)
30L Lever left side member 30R Lever right side member 40 Fourth rocking lever (any one rocking lever)
41 Lever rear member (one member)
42 Connected portion 42b Contact surface 43 Connection shaft 44 Lever tip side member (the other member)
47 Length adjusting mechanism 48 Spacer 49 Bolt as connecting member 50 Fifth swing lever 70 Variable mechanism L Opening / closing amount of valve

Claims (2)

A driving cam (8) for supplying a driving force, and a plurality of swing levers (10, 20, 30, 40, 50) that transmit the driving force to the valve (6) to open and close the valve (6). Includes a link mechanism that is connected in order to be relatively rotatable at each joint, and a variable mechanism (70) that changes the opening / closing amount (L) of the valve (6) by displacing the link mechanism. In the variable valve mechanism
A length adjusting mechanism (47) for adjusting the length of the one swing lever (40) is provided for at least one swing lever (40) of the link mechanism,
By adjusting the length with the length adjustment mechanism (47), the opening / closing amount (L) of the valve (6) can be adjusted ,
The length adjusting mechanism (47) is provided between the one swing lever (40) divided into two members (41, 44) in the length direction and the two members (41, 44). A spacer (48) inserted in a replaceable manner, and a connecting member (49) in which the two members (41, 44) are connected in a releasable manner with the spacer (48) inserted therebetween. ,
By exchanging the spacer (48) with spacers (48P, 48Q) having different thicknesses, the length of the one swing lever (40) can be adjusted,
One member (41) of the two members (41, 44) includes a connected portion (42) connected to the other member (44) by the connecting member (49), and the connected portion ( 42) extends in the width direction of the one oscillating lever (40) and is rotatable relative to the other oscillating lever (30) adjacent to the one member (41) by one of the joints. A connecting shaft (43) to be connected,
The connected portion (42) is formed larger in the radial direction of the connecting shaft (43) than the connecting shaft (43), and the connected portion (42) is a flat surface that contacts the spacer (48). A variable valve mechanism characterized in that a contact surface (42b) is provided . The connection shaft (43) is provided one on each side in the width direction of the one swing lever (40) of the coupled portion (42),
The other swing lever (30) is divided into a member (30L) connected to one of the two connecting shafts (43, 43) and a member (30R) connected to the other. The variable valve mechanism according to claim 1.

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