JP4220911B2 - Variable valve mechanism - Google Patents

Description

  The present invention relates to a variable valve mechanism that changes a valve lift amount, a working angle, and timing continuously or stepwise in accordance with the operating state of an internal combustion engine.

In Patent Document 1, a cam stroke is transmitted to an intake valve via a transmission member composed of a rocker lever and a swing arm, and the support point of the rocker lever is moved by an eccentric shaft having a variable angle. Thus, a variable valve mechanism is described in which the lift amount of the intake valve changes even with the same cam stroke. Further, in this document, at least two intake valves are provided for each cylinder of the internal combustion engine, and the transmission mechanism and the eccentric shaft are provided for each intake valve, but the eccentric shafts having different shapes between the intake valves are used. Thus, it is described that the operating angles of the two intake valves are different from each other.
Japanese Patent Laid-Open No. 7-63023

  However, when the variable valve mechanism described in Patent Document 1 is mounted on a plurality of cylinders, the valve lift amount and working angle are caused by the manufacturing accuracy and assembly accuracy of the components of the variable valve mechanism. In addition, there is a problem that timing varies between cylinders. In order to suppress this variation between cylinders, it is necessary to considerably increase the manufacturing accuracy and assembly accuracy of the component parts, but this is very expensive. Furthermore, there is a problem that almost all assembly of the variable valve mechanism must be replaced during maintenance when unacceptable variations among cylinders occur.

  Therefore, an object of the present invention is to provide the valve lift amount, the operating angle, and the timing variation between cylinders when the variable valve mechanism is mounted on a plurality of cylinders without depending on the manufacturing accuracy and assembly accuracy of the components. Another object of the present invention is to enable easy and quick adjustment with a simple configuration without replacing the assembly.

  To achieve the above object, the variable valve mechanism according to the present invention includes a swingable first intervening arm having a pressing surface that presses a pressed portion of a rocker arm, and a pressing portion that presses the first intervening arm. A second cam arm, a rotating cam that presses the rocker arm through the second intervening arm and the first intervening arm in this order, and a lift amount of the valve by sliding control of the second intervening arm, In the variable valve mechanism having a control means for changing the operating angle and timing, the control means protrudes in the radial direction from the control shaft and the control shaft and can turn the base end of the second intervening arm. And a lift control device that controls rotation of the control shaft at a small angle according to the operating condition of the internal combustion engine, and a base of the second intervening arm with respect to the protrusion. Characterized by comprising the operating angle adjusting mechanism for adjusting the operating angle of the valve by changing the relative positions of the parts.

Here, the working angle adjustment mechanism includes a base shaft that is inserted into the hole of the protruding portion so as to be relatively rotatable , and an adjustment that is eccentrically connected to the base shaft and is inserted into the hole of the second intervening arm so as to be relatively rotatable. An eccentric support shaft that changes the relative position of the proximal end portion of the second intervening arm with respect to the protruding portion by adjusting the rotation angle, and the eccentric support shaft after adjusting the rotation angle are fixed. ing from the fixture to be.

The fixing tool is a fixing nut that is screwed into a male screw formed on a protruding portion of the adjustment shaft that protrudes from the second interposed arm and is fastened to the second interposed arm.

  When this fixing nut is employed, it is preferable to provide a co-rotation regulating mechanism that regulates the co-rotation of the eccentric support shaft when the fixing nut is tightened.

  This co-rotation restricting mechanism is not particularly limited, but if the eccentric support shaft co-rotates, the eccentric support shaft works so as to move in the axial direction, and a female screw formed in the hole of the second intervening arm; Between a screw mechanism by screwing with a male screw formed on the adjustment shaft, and a locking portion provided on a protrusion of the adjustment shaft protruding from the second interposition arm, and a side surface of the second interposition arm By closely fitting, it is possible to maintain a mechanism including an adjustment shim that stops the eccentric support shaft from moving in the axial direction and restricts the eccentric support shaft from co-rotating. Examples of the locking portion of the protrusion of the adjustment shaft include a locking groove and a locking hole.

  In the present invention, the first intermediate arm and the second intermediate arm extending vertically on the side of the first intermediate arm are disposed above the rocker arm, and the side of the second intermediate arm. In addition, it is preferable that the rotary cam is arranged in that the variable valve mechanism can be made compact in the height direction. In this case, when the second intervening arm is controlled to slide up and down, the contact point between the second intervening arm and the rotary cam changes up and down, and the swinging start position of the first intervening arm changes, so that the pressed surface is pressed. When the contact position of the part changes in the length direction of the pressing surface, the lift amount, the working angle, and the timing of the valve change. Here, “upper and lower” means the axial direction of the cylinder of the internal combustion engine (refer to the direction of the axis A of the cylinder C illustrated in FIGS. 5 and 6), and “upward” means the direction away from the cylinder. . In addition, the fact that the rotating cam is arranged “side” of the second intervening arm means that the rotating cam does not become above the upper end of the second interposing arm when it is at the uppermost position. It means to be placed.

  The structure for controlling the second intervening arm to slide up and down is not particularly limited, but the second intervening arm is pivotally attached to the projecting portion of the control shaft at the base end thereof, and the control shaft is connected to the internal combustion engine. A mode in which the second intervening arm is controlled to slide up and down by being controlled to rotate at a small angle in accordance with the driving situation can be exemplified. In this example, the device for controlling the rotation of the control shaft at a small angle is not particularly limited, but a device including a helical spline mechanism, a drive unit using hydraulic pressure, and a control device such as a microcomputer can be exemplified.

Further, the second intervening arm in this illustration is not particularly limited, but the following embodiment ab can be exemplified.
a: The second intervening arm includes a cam sliding contact portion that extends downward from the base end portion thereof and is pressed by the rotating cam at the midway portion thereof, and pushes the driven portion of the first interposing arm at the lower end portion thereof. The aspect provided with the pushing part which performs.
b: The second intervening arm is provided with a cam sliding contact portion that extends upward from the base end portion thereof and is pressed by the rotating cam at the midway portion thereof, and pushes the driven portion of the first intervening arm at the upper end portion thereof. The aspect provided with the pushing part which performs.

  In the above aspect a, the first intervening arm is formed wider than the rocker arm, a pressing surface is formed at a position directly above the rocker arm of the first intervening arm, and is disengaged from a position directly above the rocker arm of the first intervening arm. It is preferable that a pushed portion is formed at the site. This is because no matter how the position of the driven portion is determined, it does not interfere with the rocker arm. Thereby, for example, the position of the pushed part can be made lower than the pressing surface.

  The first intervening arm may be pivotally mounted on the control shaft so as to be swingable independently of the small angle rotation, or may be pivotally mounted on a shaft different from the control shaft. .

  It is preferable that an urging means for urging the first intervening arm is provided so that the pushed portion always comes into contact with the pushing portion. As the biasing means, a structure in which a coil spring provided in a cylinder head of the internal combustion engine is brought into contact with the first intervening arm can be exemplified.

  The rocker arm may have a rocking center at the center in the arm length direction or at one end (so-called swing arm). The rocking center may be pivotally supported or pivotally supported. Further, it is preferable that a tappet clearance adjusting mechanism is provided at the center of swinging.

  The pressed portion of the rocker arm may be a fixed surface or a rotatable roller. The rotating cam sliding contact portion of the second intervening arm may also be a roller that can rotate on a fixed surface. The pressing portion of the second intervening arm may also be a roller that can rotate on a fixed surface. In any case, a fixed surface is preferable from the viewpoint of cost, and a rotatable roller is preferable from the viewpoint of sliding resistance and wear.

  The variable valve mechanism of the present invention can be applied to either the intake valve or the exhaust valve, but is preferably applied to both.

  When mounting a variable valve mechanism in multiple cylinders, valve lift, operating angle, and timing variations between cylinders do not depend on the manufacturing accuracy and assembly accuracy of the components, and do not depend on assembly replacement. It can be adjusted easily and quickly with a simple configuration.

  The variable valve mechanism includes a swingable first intervening arm having a pressing surface that presses a pressed portion of the rocker arm, a second interposing arm having a pressing portion that presses the first interposing arm, and a second intervening arm. A rotation cam that presses the rocker arm through the arm and the first intervening arm in that order; and a control means that changes the lift amount, the operating angle, and the timing of the valve by controlling the slide of the second intervening arm. The control means includes a control shaft, a protruding portion that protrudes in the radial direction from the control shaft and pivotally mounts the proximal end portion of the second intervening arm, and rotates the control shaft by a small angle according to the operating state of the internal combustion engine. And a lift control device for controlling, and a working angle adjusting mechanism for adjusting the working angle of the valve by changing the relative position of the base end portion of the second intervening arm with respect to the protruding portion. The working angle adjustment mechanism includes a base shaft that is inserted into the hole of the projecting portion so as to be relatively rotatable, and an adjustment shaft that is eccentrically connected to the base shaft and is inserted into the hole of the second intervening arm so as to be relatively rotatable. The eccentric support shaft which changes the relative position of the base end part of the 2nd interposition arm with respect to a protrusion part by adjusting, and the fixing tool which fixes the eccentric support shaft after adjusting a rotation angle. The fixing tool is a fixing nut that is screwed into a male screw formed on the protruding portion of the adjustment shaft that protrudes from the second intervening arm and is fastened to the second intervening arm. The co-rotation restricting mechanism for restricting the co-rotation of the eccentric support shaft when tightening the fixing nut is such that the eccentric support shaft moves in the axial direction when the eccentric support shaft rotates together. A screw mechanism formed by screwing a female screw formed in the hole and a male screw formed in the adjustment shaft, a locking portion provided on a protrusion of the adjustment shaft protruding from the second intervening arm, and the first An adjustment shim is provided that prevents the eccentric support shaft from moving in the axial direction by closely fitting between the side surfaces of the two intervening arms, thereby restricting the eccentric support shaft from co-rotating.

  1 to 7 show a variable valve mechanism of the embodiment. The variable valve mechanism is provided for each of a plurality of cylinders of the internal combustion engine. FIG. 1 shows two variable valve mechanisms for two cylinders. In each variable valve mechanism, two rocker arms 1 of a swing arm type are arranged so as to be arranged at intervals, and a concave spherical surface portion 2 formed in the same portion is supported by a pivot 30 at the base end portion of each rocker arm 1. This is the center of oscillation. The male screw at the lower part of the pivot 30 is screwed into the female screw of the pivot support member 31 so that the screwing amount can be adjusted, so that the tappet clearance can be adjusted manually. It can also be changed.) A valve pressing portion 3 that presses the proximal end portion of the valve 9 is provided at the distal end portion of the rocker arm 1. A pressed roller 4 as a pressed portion is rotatably attached to a central portion in the length direction of the rocker arm 1. In the following description, for the sake of convenience, the distal direction of the rocker arm 1 (the right direction in FIGS. 1 to 3, 5, and 6) is referred to as “front” or front or front as necessary, and the proximal direction (also the left direction). ) "Back" or rear or rear as required.

  In this embodiment, above the rocker arm 1, a swingable first intervening arm 10 having a pressing surface 17 that presses the pressed roller 4, a control shaft 27, and a front side of the first interposing arm 10 are vertically moved. And a second intervening arm 20 that is controlled to slide up and down by a control shaft 27, and a rotating cam 7 is disposed in front of the second intervening arm 20. These are described in detail below.

  The first intervening arm 10 includes two arm bodies 11 arranged at intervals corresponding to the two rocker arms 1, a connecting portion 12 that connects both arm bodies 11, and a pressed portion that extends from the front portion of the connecting portion 12. The moving part 13 and the protruding part 14 extending from the rear part of the connecting part 12 are included. Each arm main body 11 is provided on a lower side of each boss portion 15 and a cylindrical boss portion 15 that is rotatably inserted into a control shaft 27 described later to make the first intervening arm 10 swingable. Furthermore, it comprises an arm portion 16 extending forward. The lower surface of the arm portion 16 is a pressing surface 17 that presses the pressed roller 4, and the pressing surface 17 in the illustrated example is a convex arcuate surface whose second half portion is approximately equal in distance to the swing center of the first intervening arm 10. The non-working surface portion 17a is a working surface portion 17b whose front half is away from the swing center of the first intervening arm 10 toward the front side. The center of swing of the first intervening arm 10 is slightly behind the pressed roller 4, and the pressing surface 17 extends from the rear of the pressed roller 4 to the upper part of the rocker arm 1. ing.

  The connecting portion 12 is formed in a half-cylindrical shape from which the upper half of the cylinder is removed in order to escape a protruding portion 28 described later, and connects the boss portions 15 together. The driven portion 13 is formed in a plate shape that extends forward and downward from the front portion of the connecting portion 12, and enters the space between the two rocker arms 1 without contact. In other words, the first intervening arm 10 is formed wider than the rocker arm 1 by the amount of the connecting portion 12 and the driven portion 13, and the pressing surface 17 is formed in the first intervening arm 10 directly above the rocker arm 1. A pushed portion 13 is formed in a portion of the first intervening arm 10 that is deviated from the portion directly above the rocker arm 1. Therefore, since the pushed portion 13 does not interfere with the rocker arm 1, the position of the pushed portion 13 is set lower than the action surface portion 17 b of the pressing surface 17. Although the upper surface of the pushed portion 13 in the illustrated example is substantially flat, it may be a curved surface. The projecting portion 14 extends rearward from the rear portion of the connecting portion 12, and an indenter 19 urged by a coil spring 18 provided on the cylinder head is in contact with the upper surface of the projecting portion 14, so that the driven portion 13 is pressed later. It is made to always contact | abut to the pushing roller 22 as a moving part.

  The control shaft 27 is pivotally supported by a support mechanism (not shown) so as to be rotatable at a small angle. A protruding portion 28 that protrudes forward in the radial direction of the shaft is provided above the interval between the two rocker arms 1 in the control shaft 27. The projecting portion 28 is fixed to the upper portion of the control shaft 27 by a pin 29 at the base end portion thereof, and is rotated by a small angle integrally with the control shaft 27. The first intervening arm 10 is rotatable independently of this small angle rotation. There is no particular limitation on the method of stopping the protruding portion 28 with respect to the control shaft 27, and the control shaft 27 and the protruding portion 28 may be integrally formed.

  The second intervening arm 20 is pivotally attached to the projecting portion 28 at the base end portion (upper end portion in this example), and extends downward from the base end portion, so that the control shaft 27 is in an operating state of the internal combustion engine. In response to the small-angle rotation control, vertical slide control is performed between the control shaft 27 and the rotary cam 7. A relatively medium-diameter hole 32 is formed in the protrusion 28 that pivotally mounts the second intervening arm 20. The second intervening arm 20 includes two fork portions 23 and 23 and a connecting portion 24 that connects the fork portions 23 and 23 with a space therebetween, and has a relatively small diameter at a base end portion of one fork portion 23 sandwiching the protruding portion 28. And a relatively large-diameter hole 26 is formed at the base end of the other fork 23 (both holes 25 and 26 are coaxial). A relatively small-diameter base shaft 34, a relatively small-diameter first adjustment shaft 35 eccentrically connected to one end of the base shaft 34, and the other end of the base shaft 34 are eccentric in the same manner as the first adjustment shaft 35. (Therefore, both adjusting shafts 35 and 36 are coaxial.) An eccentric support shaft 33 composed of a connected relatively large-diameter second adjusting shaft 36 is used. The eccentric support shaft 33 is inserted into the second intervening arm 20 from the large-diameter hole 26 side so that the first adjustment shaft 35, the base shaft 34, and the second adjustment shaft 36 can rotate relative to the holes 25, 32, and 26, respectively. By being inserted, the second intervening arm 20 is pivotally attached to the projecting portion 28 as described above. Here, the axis center of the base shaft 34 is Oa, and the axis center Ob of both the adjustment shafts 35 and 36 is set.

  A jig engaging portion 37 is formed on the end surface of the second adjustment shaft 36, and a jig (not shown) such as a wrench is engaged with the jig engaging portion 37 to rotate the eccentric support shaft 33. The rotation angle of the support shaft 33 can be adjusted. As a result, the valve operating angle can be adjusted by changing the relative position of the base end portion of the second intervening arm 20 with respect to the protruding portion 28 around the axis center Oa of the base shaft 34 as described later. Then, the eccentric support shaft 33 after adjusting the rotation angle is fixed as a fixture screwed to a male screw 39 formed on the protrusion of the first adjustment shaft 35 protruding from the one fork portion 23. The nut 41 is fixed to the second intervening arm 20 by tightening it on the side surface of the fork portion 23. In the present embodiment, the working angle adjusting mechanism is constituted by the holes 32, 25, 26, the eccentric support shaft 33, and the fixing nut 41. Further, when the eccentric support shaft 33 rotates together with the fixing nut 41 when the fixing nut 41 is tightened, the adjustment of the working angle is out of order, so that the rotation is restricted so that the rotation does not occur. A regulation mechanism is provided.

  The co-rotation restricting mechanism according to the present embodiment is formed by screwing a female screw 38 formed in the hole 25 of one fork portion 23 and a male screw 39 formed on the first adjustment shaft 35 (not only the protruding portion). And a flat circular arc that fits tightly between a locking groove 42 of a predetermined width provided on the protrusion of the second adjustment shaft 36 protruding from the other fork 23 and the side surface of the fork 23. It comprises a cutout adjustment shim 43. The former screw mechanism works so that the eccentric support shaft 33 moves in the axial direction if the eccentric support shaft 33 rotates together. As will be described later with reference to FIG. 4, the latter adjusting shim 43 stops the eccentric support shaft 33 from moving in the axial direction by tightly fitting the selected one between them, and thus the eccentric support shaft 33. Regulates co-rotation. Although the adjustment shim 43 of the present embodiment includes a grip portion 44 that extends long so that it can be gripped by hand, it may be provided with a knob portion 45 that can be pinched with a fingertip, as shown at the top of FIG. . Further, in the present embodiment, for the sake of safety, the fixing screw 40 as a fixture screwed into the small screw holes of the both fork portions 23 and 23 is fastened to both the first adjusting shafts 35 and 36, thereby adjusting the adjusting shaft. Although 35 and 36 are fixed to the holes 25 and 26, the fixing screw 40 can be omitted.

  A cam sliding roller 21 serving as a cam sliding contact portion pressed against the rotating cam 7 is rotatably attached to the middle portion of the second intervening arm 20. A pushing roller 22 as a pushing portion that pushes the pushed portion 13 of the first interposing arm 10 is rotatably attached to the distal end portion (lower end portion in this example) of the second interposing arm 20. Yes. Since the width of the second intervening arm 20 is narrower than the interval between the two rocker arms 1 and the interval between the two arm bodies 11, the lower end of the second intervening arm 20 enters these intervals in a non-contact manner and pushes. The roller 22 is brought into contact with the driven portion 13. In this example, the base end portion of the second intervening arm 20, the cam sliding contact portion (cam sliding contact roller 21) at the middle portion, and the pushing portion (pushing roller 22) at the distal end portion are rotated by the cam sliding contact portion. It has a “<” shape arrangement (side view) protruding to the cam 7 side. The second intervening arm 20 interposed between the rotating cam 7 and the pushed portion 13 is designed so that the distance between the rotating cam 7 and the pushed portion 13 can be changed by sliding up and down. .

  One camshaft 6 is rotatably supported on the side of the second intervening arm 20. A rotating cam that lifts the valve 9 by pressing the rocker arm 1 through the second intervening arm 20 and the first interposing arm 10 in this order by pressing the cam sliding contact roller 21 to the camshaft 6 sideways. 7 is formed. The rotating cam 7 includes a base circle 7a, a nose gradually increasing portion 7b in which the protruding amount gradually increases, a nose 7c having the maximum protruding amount, and a nose gradually decreasing portion 7d in which the protruding amount gradually decreases. The rotating direction of the rotating cam 7 is a direction in which the nose 7c approaches the cam sliding roller 21 from above (counterclockwise in the illustrated example). Then, the rotation center of the rotating cam 7 (the axis of the camshaft 6) does not rise above the upper end of the second interposed arm 20 at the uppermost position (FIG. 6). A rotating cam 7 is arranged on the front side.

  The control shaft 27 is controlled to rotate at a small angle according to the operating condition of the internal combustion engine, and the orientation angle of the protrusion 28 is continuously or stepwise within a range of one rotation (at least two steps, preferably Is provided with a lift control device (not shown) that controls the second intervening arm 20 to slide up and down as described above. When the second intervening arm 20 is controlled to slide up and down, the contact point between the cam sliding contact roller 21 and the rotating cam 7 changes up and down, and at the same time, the push roller 22 displaces the pushed portion 13 and the first intervening arm. 10, and the contact position P of the pressed roller 4 on the pressing surface 17 changes in the length direction of the first intervening arm 10, thereby changing the lift amount, working angle, and timing of the valve 9. To do.

  In the lift control device, for example, a piston provided with a helical spline moves in the axial direction while rotating at a predetermined angle by hydraulic pressure, and the rotation rotates the control shaft 27, whereby the orientation angle of the protrusion 28 is within one rotation. In this range, the control is performed by a control device such as a microcomputer based on a detection value from a rotation sensor, an accelerator opening sensor, or the like of the internal combustion engine. The lift control device may use a motor such as a step motor, for example.

  The variable valve mechanism of this embodiment operates as follows when mounted on an internal combustion engine. When mounting to multiple cylinders, the valve lift, operating angle, and timing vary among the cylinders due to the manufacturing accuracy and assembly accuracy of the components between the cylinders. There is. That is, as shown in FIG. 3, when the base circle 7a of the rotating cam 7 is in contact with the cam sliding contact roller 21, a gap between the push roller 22 and the pushed portion 13 (actually by the coil spring 18). Since the first intervening arm 10 is urged, this means a gap between the pressing surface 17 and the pressed roller 4) is managed at a design value (0 or a predetermined clearance). However, even if the clearance fits the design value in one cylinder, the clearance may not match the design value due to the above-mentioned variation in other cylinders, and the valve operating angle may change. It is necessary to adjust the corner.

  In the present embodiment, this adjustment is performed by the working angle adjustment mechanism. That is, as shown in FIG. 1, a jig (not shown) is engaged with the jig engaging portion 37 of the second adjustment shaft 36 to adjust the rotation angle of the eccentric support shaft 33, thereby FIG. ) (B) and FIGS. 4 (a) and 4 (b), the relative position of the proximal end portion of the second intervening arm 20 with respect to the protruding portion 28 is set to the amount of eccentricity around the axial center Oa to the axial center Ob. Change by turning as radius. For example, if the position of the proximal end of the intervening arm 20 is changed so that Ob is oriented to the upper right with respect to Oa as shown in FIG. 3A, the gap between the pushing roller 22 and the pushed portion 13 increases. It can adjust to the direction to do ((a) in FIG. 4). Moreover, if the position of the base end part of the interposition arm 20 is changed so that Ob is oriented to the lower left with respect to Oa as shown in FIG. 3B, the gap can be adjusted to decrease (in FIG. 4, (b )). FIG. 3B is a virtual diagram in which a virtual state in which the push roller 22 bites into the pushed portion 13 and the gap becomes negative is shown by being filled. Therefore, if the position of the base end portion of the second intervening arm 20 is appropriately changed according to the degree of the gap caused by the variation between the cylinders, the gap can be adjusted to the design value. The adjustment operation can be performed only by a simple operation of adjusting the rotation angle of the eccentric support shaft 33, and there is no need to depend on the manufacturing accuracy and assembly accuracy of the component parts or to replace the assembly as in the conventional example. It can be adjusted easily and quickly with a simple configuration.

  After this adjustment, the eccentric support shaft 33 may be fixed by tightening the fixing nut 41 as described above. When tightening, it is necessary to prevent the eccentric support shaft 33 from co-rotating as described above. For this purpose, there is a method of holding a rotation angle of the eccentric support shaft 33 by engaging a jig (not shown) with the jig engaging portion 37, but it is troublesome and difficult to hold the jig by hand. . Therefore, in this embodiment, the co-rotation restricting mechanism is provided. The screw mechanism by screwing of the female screw 38 and the male screw 39 moves the eccentric support shaft 33 in the axial direction even when adjusting the operating angle by adjusting the rotation angle of the eccentric support shaft 33. 4 (a) and (b), the width between the locking groove 42 and the side surface of the fork portion 23 changes. For this reason, the adjustment shim 43 is selected from among a large number of adjustment shims 43 having a rank in thickness, and the adjustment shim 43 is closely fitted between them. By the simple operation of only fitting, the eccentric support shaft 33 can be prevented from moving in the axial direction, and thus the eccentric support shaft 33 can be easily restricted from co-rotating. Since the thickness of the flat adjustment shim 43 can be made relatively easily, the thickness rank can be set finely so that the working angle can be finely adjusted. In addition, after tightening the fixing nut 41 while restricting the co-rotation of the eccentric support shaft 33, the adjustment shim 43 may be pulled out from the above and removed.

Further, the variable valve mechanism of the present embodiment operates as follows during operation of the internal combustion engine.
First, FIG. 5 shows the time when the nose 7c contacts the cam sliding contact roller 21 in a driving condition where the maximum lift amount and the maximum operating angle are required (so-called nose time), and FIGS. ) Is different from the cutting position of the cross section. Under this operating condition, the projecting portion 28 is oriented to the lowest side by the small-angle rotation control of the control shaft 27, and the second intervening arm 20 is slid to the lowest position. Then, as shown in FIG. 3, when the base circle 7a comes into contact with the cam sliding contact roller 21 (so-called base), the push roller 22 enters the pushed portion 13 between the two rocker arms 1 at its front end. Therefore, the arm portion 16 is in a position inclined forward and downward, and this is the swing start position of the first intervening arm 10. At this time, the contact position of the pressed roller 4 is at the front end portion of the non-working surface portion 17a, and the valve 9 is not lifted. Then, at the nose of FIG. 5, the rotating cam 7 presses the cam sliding roller 21 to the maximum, the second intervening arm 20 swings to the maximum back, and the push roller 22 moves the pushed portion 13 forward. Push down to the maximum. For this reason, the first intervening arm 10 swings forward and downward to the maximum, the pressed roller 4 abuts against the working surface portion 17b, and the rocker arm 1 swings forward and downward to the maximum, so the lift amount L of the valve 9 is The maximum value Lmax is reached. Further, the contact position P at the base is at the front end of the non-working surface portion 17a, and the valve 9 is lifted in a wide range from the start of the first intervening arm 10 to the maximum swinging. The corner is the maximum. Further, since the nose 7c approaches the cam sliding contact roller 21 from above, since the contact point between the cam sliding contact roller 21 and the rotating cam 7 is on the lower side, the timing at which the lift peak comes is the most retarded. (See FIG. 7).

  Next, FIG. 6 shows a nose state under an operating condition that requires a minute lift amount and a minute working angle, and (a) and (b) in FIG. Under this operating condition, the projecting portion 28 is oriented upward from the time of FIG. 5 by the small-angle rotation control of the control shaft 27, and the second intervening arm 20 is slide controlled to a position above the time of FIG. . Then, at the base time (not shown), the amount by which the driven portion 13 is pushed down by the pressing roller 22 is reduced, so that the arm portion 16 is positioned above the time of FIG. This is the swing start position. At this time, the contact position of the pressed roller 4 is in the middle of the non-working surface portion 17a, and the valve 9 is not lifted. 6, the rotating cam 7 presses the cam sliding contact roller 21, the second intervening arm 20 swings rearward, and the push roller 22 pushes the pushed portion 13 forward and downward. . Therefore, although the first intervening arm 10 swings forward and downward, it swings from the high swing start position, so that it swings only to the upper side than in FIG. For this reason, the contact position P of the pressed roller 4 advances only to the point where it starts to be applied to the action surface portion 17b. Therefore, the rocker arm 1 only slightly swings forward and downward, and the lift amount of the valve 9 becomes minute. Further, the contact position P at the time of base is in the middle of the non-working surface portion 17a, and the valve 9 is not lifted until the first intervening arm 10 is swung to some extent, so that the working angle becomes small. Further, since the nose 7c approaches the cam sliding contact roller 21 from above, the contact point between the cam sliding contact roller 21 and the rotating cam 7 is on the upper side. (See FIG. 7).

  Under an operating situation where an intermediate lift amount / working angle between FIGS. 5 and 6 is required, the projecting portion 28 is oriented to an intermediate position between FIGS. 5 and 6 by small-angle rotation control of the control shaft 27. By controlling the second intervening arm 20 to slide up and down continuously or stepwise to an intermediate position between FIG. 5 and FIG. 6, an intermediate lift amount / working angle / timing can be obtained as shown in FIG. Obtained continuously or stepwise.

  Further, under an operating condition that requires a lift stop, the projecting portion 28 is oriented further upward than in the case of FIG. 6 by the small-angle rotation control of the control shaft 27, and the second intervening arm 20 is further further than in the case of FIG. By performing sliding control to the upper position, the lift amount of the valve 9 can be reduced to zero.

  According to the variable valve mechanism of the present embodiment configured as described above, the lift amount, the working angle, and the operating angle of the valve 9 can be obtained simply by rotating one camshaft 6 without greatly changing the conventional drive system. The timing can be changed continuously or stepwise. In addition, the first intervening arm 10 and the second intervening arm 20 extending vertically are disposed above the rocker arm 1, and the rotating cam 7 is disposed on the side of the second intervening arm 20. It is possible to form a compact variable valve mechanism that suppresses this. For this reason, the vehicle mounting property of the variable valve mechanism can be improved. Particularly in this embodiment, the position of the driven portion 13 is set lower than the pressing surface 17 so that the pressing roller 22 can enter between the two rocker arms 1. It can arrange | position lower, and the rotation cam 7 is also easy to arrange | position lower.

In addition, this invention is not limited to the structure of the said Example, For example, as follows, it can also change and actualize in the range which does not deviate from the meaning of invention.
(1) Change the configuration and control method of the lift control device as appropriate.
(2) Use a rocker arm with a rocking center at the center.
(3) Change the shape of the second intervening arm 20 as appropriate.
(4) Change the shape of the pressing surface 17 as appropriate.
(5) In the second intervening arm 20, a cam slide contact tip is used instead of the cam slide roller 21, and a push tip is used instead of the push roller 22.
(6) The arm part 16 of the first intervening arm 10 extends rearward from the lower side of the boss part 15, the pushed part 13 extends upward from the upper part of the coupling part 12, and the protruding part of the control shaft 27 Even if the position of 28 is lowered and the second intervening arm 20 extends upward from the base end portion pivotally attached to the projecting portion 28, the same effect can be obtained.

It is a perspective view which shows the variable valve mechanism based on the Example of this invention. It is a perspective view which shows the state which decomposed | disassembled the principal part of the mechanism. The working angle adjustment mechanism in the same mechanism is shown, (a) is an explanatory diagram when adjusting in the direction in which the gap between the push roller and the driven part increases, and (b) is adjusted in the direction in which the gap decreases. It is explanatory drawing at the time. (A) is IVa-IVa sectional drawing of FIG. 3, (b) is IVb-IVb sectional drawing of FIG. (A) which shows an effect | action when the maximum lift amount and the maximum working angle of the mechanism are required is sectional drawing, (b) is a side view. FIG. 5A is a cross-sectional view and FIG. 5B is a side view showing an operation of the mechanism when a micro lift amount and a micro operation angle are necessary. It is a graph which shows the lift amount of a valve | bulb obtained by the variable valve mechanism based on a present Example, a working angle, and timing.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rocker arm 4 Pressed roller 6 Camshaft 7 Rotating cam 9 Valve 10 1st interposition arm 13 Pushing part 17 Pressing surface 20 2nd interposition arm 21 Cam sliding roller 22 Pushing roller 25 Hole 26 Hole 27 Control shaft 28 Projection Portion 32 Hole 33 Eccentric support shaft 34 Base shaft 35 First adjustment shaft 36 Second adjustment shaft 37 Jig engagement portion 38 Female screw 39 Male screw 41 Fixing nut 42 Locking groove 43 Adjustment shim

Claims (3)

A swingable first intervening arm having a pressing surface for pressing the pressed portion of the rocker arm, a second interposing arm having a pressing portion for pressing the first interposing arm, the second interposing arm and the first A variable valve mechanism comprising: a rotating cam that presses the rocker arm through one intervening arm in that order; and a control means that changes the lift amount, operating angle, and timing of the valve by sliding control of the second intervening arm In
The control means includes a control shaft, a projecting portion projecting in a radial direction from the control shaft and pivotally mounted on a proximal end portion of the second intervening arm, and the control shaft according to an operating condition of the internal combustion engine A lift control device that controls rotation at a small angle, and a working angle adjusting mechanism that adjusts the working angle of the valve by changing the relative position of the base end portion of the second intervening arm with respect to the protruding portion,
The working angle adjustment mechanism includes a base shaft that is inserted into the hole of the projecting portion so as to be relatively rotatable, and an adjustment shaft that is eccentrically connected to the base shaft and is inserted into the hole of the second interposed arm so as to be relatively rotatable. An eccentric support shaft that changes a relative position of a base end portion of the second intervening arm with respect to the protrusion by adjusting a rotation angle; and a fixture that fixes the eccentric support shaft after adjusting the rotation angle. Consists of
The variable valve mechanism characterized in that the fixing tool is a fixing nut that is screwed into a male screw formed on a protruding portion of the adjusting shaft that protrudes from the second interposed arm and is fastened to the second interposed arm. . Variable valve mechanism according to claim 1, wherein providing the co-rotating restricting mechanism for restricting a co-rotating of the eccentric shaft when tightening the fixing nut. The co-rotation restricting mechanism is formed on a female screw formed in a hole of the second intervening arm and the adjustment shaft so that if the eccentric support shaft rotates together, the eccentric support shaft moves in the axial direction. By closely fitting between a screw mechanism by screwing with a male screw and a locking portion provided on a protruding portion of the adjusting shaft protruding from the second interposed arm and a side surface of the second interposed arm. 3. The variable valve mechanism according to claim 2, further comprising an adjustment shim that stops the eccentric support shaft from moving in the axial direction and restricts the eccentric support shaft from co-rotating.

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