JP5375112B2 - Engine valve gear - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily adjust the lift of a valve without deteriorating the performance thereof. <P>SOLUTION: A lift adjustment mechanism 41 includes a pair of screw members 44, 45 which are screwed with respective female screw parts 43a, 43b formed in a link arm 12 and a pin member 21 held by the pair of screw members 44, 45 in the small end 12b of the link arm 12. The position of the pin member 21 is changed by rotating the pair of screw members 44, 45. Consequently, the lift of the valve gear can be finely adjusted without disassembling the valve gear 10. The inertia mass of a swing arm 14 is reduced by providing a lift adjustment mechanism 41 to the link arm 12 more than in a case in which the lift adjustment mechanism 41 is provided to the swing arm 14. Consequently, since the polar inertia moment of the swing arm 14 is reduced, the polar inertia moment of the entire part of the valve gear 10 can be reduced. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to an engine valve operating device capable of varying a valve lift amount.

2. Description of the Related Art Conventionally, variable valve gears that can vary the valve lift amount of a valve are widely known. Such a variable valve device includes a rocking cam rotatably supported on the outer periphery of the drive shaft, and this rocker cam is rotatably mounted on the eccentric cam portion of the control shaft by a link rod. The intake valve is configured to open against the valve spring reaction force in response to the swing. Here, the rocker arm is linked to a drive cam provided on the drive shaft via a link arm. Since such a variable valve device is composed of many members, variations in valve lift amount between cylinders are likely to occur due to manufacturing errors, assembly errors, and the like.

  Therefore, for example, in Patent Document 1, a lift adjusting mechanism is provided in the rocker arm to remove the lift variation between the cylinders in the above-described conventionally known variable valve gear, and the rocker arm and the link rod can be rotated. A structure is disclosed in which the position of the support pin linked to the rocker arm can be changed. The lift adjustment mechanism in this Patent Document 1 is a substantially rectangular block-like linkage part integrally provided on the rocker arm, and is formed inside from the upper surface of the linkage part, and a fixing screw member is screwed from above. An internal female screw hole, a pin insertion hole that is formed through both sides of the linkage portion in a direction perpendicular to the female screw hole and through which the support pin is inserted, and coaxial with the fixing female screw hole from the lower surface of the linkage portion An adjustment female screw hole formed in the adjustment screw member to be barely attached from below, and the support pin is sandwiched between the fixing screw member and the adjustment screw member, and positions of these screws By changing the position of the support pin, the position of the support pin can be changed.

  Further, for example, Patent Document 2 discloses that the link arm is provided with a lift adjustment function for removing lift variation between cylinders in the above-described conventionally known variable valve device. That is, in Patent Document 2, the link arm has a large end portion slidably fitted to the drive cam, and a small end portion slidably fitted to a pin-like member protruding from the rocker arm. The distance between the small end portion and the large end portion, in other words, by engaging a male screw formed at the small end portion with a female screw formed at the large end portion. The dimension (length) between the center of the drive cam and the center of the pin-shaped member in the link arm can be changed.

JP 2006-105082 A JP 2001-123809 A

  In the above-described variable valve device of Patent Document 1, the side that converts the rotation of the drive cam into the swing motion of the swing arm is the primary side (input side), and the swing motion of the swing arm is the above-described swing motion. If the side converted into the swing motion of the swing cam via the link rod is the secondary side (output side), the lift adjusting mechanism is provided on the secondary side.

  Therefore, as in Patent Document 1, if the lift adjustment mechanism is provided on the secondary side (output side) of the valve gear, that is, the swing arm, the inertial mass of the swing arm itself increases, and the swing control mechanism further increases. Not only does the pole arm moment of inertia (Ip) increase, but the pole moment of inertia (Ip) of the valve operating apparatus as a whole increases, which is disadvantageous for high-speed operation.

  Further, in the variable valve operating device of Patent Document 2, the small end of the link arm is screwed and fixed to the large end of the link arm, so that the small end is only at 1/2 pitch of the screw. The distance between the part and the large end part cannot be changed, and the adjustment resolution for lift adjustment is rough, and the desired adjustment accuracy may not be obtained.

Therefore, the present invention provides a drive shaft that rotates in synchronization with engine rotation, a drive cam provided on the drive shaft, a link arm that is fitted on the outer periphery of the drive cam so as to be relatively rotatable, and the drive shaft. A rotatable control shaft provided in parallel and having a main shaft portion and an eccentric cam portion, and rotatably mounted on the eccentric cam portion of the control shaft, and linked to the link arm via a first rotation fulcrum An oscillating arm, a link rod linked to the oscillating arm via a second rotation fulcrum, and connected to the oscillating arm via the link rod, and oscillates with the oscillating arm. And a rocking cam that presses the valve, so that the link arm is relatively rotatable on the outer periphery of the first rotation fulcrum and a large end portion that is fitted to the outer periphery of the drive cam. A small end that fits into the large end and the front In the valve operating apparatus for an engine having a connecting portion between the small end portions and connecting the two, the link arm adjusts the lift amount of the valve operating by changing the position of the first rotation fulcrum. A lift adjustment mechanism, and the lift adjustment mechanism includes a pair of screw members respectively engaged with female screw portions formed on the link arm, and the pair of screw members within the small end portion of the link arm. A supported member to be clamped, and configured to change the position of the first rotation fulcrum by changing the position of the supported member to be clamped in the small end, and Is formed with a through hole along the axial direction of the supported member or an accommodation hole for accommodating one of the pair of screw members, and the linkage portion is thinned by the through hole or the accommodation hole. It is characterized in that.

  According to the present invention, by rotating the pair of screw members and changing the position of the first rotation fulcrum, the lift amount of the valve can be finely adjusted without disassembling the valve device.

  Further, by providing the link arm with the lift adjustment mechanism, the inertial mass of the swing arm can be reduced as compared with the case where the lift adjustment mechanism is provided on the swing arm. Therefore, the polar moment of inertia of the swing arm is reduced, and as a result, the polar moment of inertia of the entire valve operating apparatus can be relatively reduced.

The perspective view of the valve operating apparatus of the engine in 1st Embodiment of this invention. The side view of the valve operating apparatus of the engine in 1st Embodiment of this invention. The perspective view of the link arm in 1st Embodiment of this invention. The front view of the link arm in 1st Embodiment of this invention. Compare the valve operating mechanism in which the link arm and link rod are connected to the swing arm with the control shaft in between, and the valve operating mechanism in which the link arm and link rod are connected to the swing arm on the same side of the control shaft. (A-1) is a side view showing the state of the link when the valve is opened in the valve mechanism in which the link arm and the link rod are connected to the swing arm across the control shaft. (A-2) is a front view of the valve mechanism shown in (A-1). (B-1) is a motion in which the link arm and the link rod are connected to the swing arm on the same side with respect to the control shaft. The side view which shows the state of the link when opening a valve in a valve mechanism, (B-2) is a front view of the valve mechanism shown in (B-1). Explanatory drawing which showed the link arm typically. Explanatory drawing which shows the result of having investigated the mode of a deformation | transformation when a tensile load is made to act on a link arm by the finite element method. Explanatory drawing which separated and showed the link arm and the rocking | fluctuating arm. Explanatory drawing which separated and showed the link arm and the rocking | fluctuating arm. The perspective view of the valve operating apparatus of the engine in 2nd Embodiment of this invention. The side view of the valve operating apparatus of the engine in 2nd Embodiment of this invention. Explanatory drawing which shows the link arm and lift adjustment mechanism in 2nd Embodiment of this invention. The perspective view of the 2nd screw member in a 2nd embodiment of the present invention. The perspective view of the valve operating apparatus of the engine in 3rd Embodiment of this invention. The side view of the valve operating apparatus of the engine in 3rd Embodiment of this invention. Explanatory drawing which shows the link arm and cylindrical member in 3rd Embodiment of this invention. The perspective view of the cylindrical member in 3rd Embodiment of this invention. Explanatory drawing which shows other embodiment of this invention. Explanatory drawing which shows other embodiment of this invention.

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

  FIG.1 and FIG.2 is explanatory drawing which showed typically the valve operating apparatus 10 of the engine in 1st Embodiment, FIG. 1 is a perspective view, FIG. 2 is a side view.

  The valve gear 10 includes two valve valves (for example, intake valves) (not shown) per cylinder, and the valve lift amount of the valve valves can be changed according to the operating state of the engine. More specifically, in the valve operating apparatus 10 of the first embodiment, the valve lift amount becomes smaller in the low speed and low load range than in the high speed and high load range, and the lift operating angle of the valve, that is, the valve opening of the valve. The period can be changed so that the valve lift amount becomes larger and the valve lift operating angle, that is, the valve opening period becomes larger in the high speed and high load range than in the low speed and low load range. It can be changed. That is, in the valve operating apparatus 10, when the valve lift amount of the valve is increased, the lift operating angle of the valve is increased, and when the valve lift amount of the valve is decreased, the lift operating angle of the valve is also decreased.

  The valve gear 10 includes a drive shaft 11 rotatably supported on the cylinder head along the longitudinal direction of the engine (cylinder row direction), a drive cam 112 provided on the drive shaft 11, and an outer peripheral surface of the drive cam 112. A link arm 12 (details will be described later) fitted in a relatively rotatable manner with the drive shaft 11 and provided with a main shaft portion 131, an eccentric cam portion 132, and a web plate 133. The control shaft 13, the swing cam 14 that is rotatably attached to the eccentric cam portion 132 of the control shaft 13, and is swingably supported by the drive shaft 11, and swings. A swing cam 16 is connected to the arm 14 via an elongated link rod 15 and swings with the swing arm 14 to press a valve (not shown). Is, the swing cam 16 in response to a drive shaft 11 which rotates in synchronism with engine rotation to open or close the valve operating swings. The drive shaft 11 and the control shaft 13 are rotatably supported by a bearing (not shown).

  The drive shaft 11 is rotated by torque transmitted from an engine crankshaft (not shown), and is composed of a cylindrical drive shaft main body 111 and a drive cam 112. A main oil passage 31 is formed in the drive shaft main body 111. The drive cam 112 is fixed to the drive shaft main body 111 and rotates integrally with the drive shaft main body 111. The drive cam 112 is an eccentric rotation cam deviated from the axis of the drive shaft main body 111. The drive cam 112 has a cam body 112a and a boss portion 112b, and the cam body 112a and the boss portion 112b are integrally formed. The axis of the cam body 112a is set to be offset from the axis of the drive shaft main body 111 by a predetermined amount in the radial direction.

  The control shaft 13 has a crank shape in which the shaft center of the eccentric cam portion 132 is offset with respect to the shaft center of the main shaft portion 131, and the main shaft portion 131 and the eccentric cam portion 132 are connected via a thin plate-like web plate 133. Yes. The control shaft 13 is controlled to rotate within a predetermined rotation angle range by an actuator (not shown). The actuator controls the rotation of the control shaft 13 based on the current operating state of the engine detected from detection signals from various sensors such as a crank angle sensor, an air flow meter, and a water temperature sensor. When the control shaft 13 is rotationally controlled, the eccentric position of the eccentric cam portion 132 is adjusted, and the swing center of the swing arm 14 is changed. And according to the rotation angle position of the control shaft 13, the lift and the operating angle of the valve are continuously expanded and reduced simultaneously.

  The swing arm 14 is generally composed of a cap 141 and an arm body 142 that is a first rotation fulcrum supported by the link arm 12 and is linked to a pin member 21 (described later) that is a supported member. 141 and the arm body 142 located on the drive shaft 11 side of the cap 141 sandwich the eccentric cam portion 132 and rotatably support it. In other words, the swing arm 14 has a circular cross-sectional hole that rotatably supports the control shaft support portion 143 that rotatably supports the eccentric cam portion 132 of the control shaft 13 and the pin member 21 supported by the link arm 12. Part 18 (see FIG. 8 described later). The control shaft support portion 143 includes a cap side control shaft support portion 36 formed on the cap 141 and an arm body side control shaft support portion 37 formed on the arm body 142. The cap 141 and the arm body 142 are coupled by a bolt 38.

  The link rod 15 is rotatably connected to the arm body 142 of the swing arm 14 via a pin 22 whose one end is a second rotation fulcrum, and the swing cam 16 is connected via a pin 23 whose other end is a rotation fulcrum. It is connected to be rotatable. In other words, one end of the link rod 15 is connected to the other end side of the swing arm 14 via the pin 22. That is, the link rod 15 is linked to the swing arm 14 via the pin 22 located on the same side as the pin member 21 with respect to the control shaft 13. Here, the pin 22 is further away from the axis of the eccentric cam portion 132 than the pin member 21.

  The swing cam 16 is a pair of members fixed to the pipe 17, and the pipe 17 is inserted through the drive shaft 11 and swingable about the drive shaft 11. The valve is opened and closed by the rotation of the swing cam 16.

  As shown in FIGS. 1 to 4, the link arm 12 rotates relative to the outer periphery of the pin member 21 serving as the first rotation fulcrum and the large end portion 12 a fitted to the outer peripheral surface of the drive cam 112. Link by changing the position in the small end part 12b of the small end part 12b which fits between, the link part 12c which exists between the large end part 12a and the small end part 12b, and connects both, and the pin member 21 A lift adjusting mechanism 41 that can adjust the lift amount of the valve by substantially changing the length of the arm 12, and is disposed adjacent to the swing arm 14. In the first embodiment, a through hole 42 is formed in the linkage part 12c along the axial direction of the drive shaft 11 (perpendicular to the paper surface in FIG. 4), and the linkage part 12c is thinned.

  The lift adjustment mechanism 41 includes a first screw member 44 and a second screw member 45 which are a pair of upper and lower screw members that are screwed into female screw portions 43a and 43b formed on the link arm 12, and the first and second screw members. A cylindrical pin member 21 sandwiched between the small ends 12 b of the link arm 12 by the members 44 and 45.

  The female screw portion 43a once opened on the outer periphery of the small end portion 12b and the female screw portion 43b once opened in the through hole 42 of the linkage portion 12c are straight lines passing through the center of the large end portion 12a and the center of the small end portion 12b. And is formed coaxially.

  The first screw member 44 has a hexagonal head. In the second screw member 45, a hole (for example, a hexagon) having the same cross-sectional shape as the cross-sectional shape of the spanner used when the second screw member 45 is turned is formed on the end face on the through hole 42 side.

  A planar seat surface 46 is formed in a portion of the outer peripheral surface of the pin member 21 that is located in the small end portion 12b and is sandwiched between the first screw member 44 and the second screw member 45.

  Then, the lift adjustment mechanism 41 rotates the first screw member 44 from the outer peripheral side (the upper side in FIG. 4) of the small end portion 12b, and the second screw member from the through hole 42 side (the lower side in FIG. 4) of the linkage portion 12c. By turning 45, the position within the small end portion 12b of the pin member 21 can be changed.

  Here, in the valve operating apparatus 10 of the first embodiment, the pin member 21 that is the rotation fulcrum of the swing arm 14 with respect to the link arm 14 and the pin 22 that is the rotation fulcrum of the link rod 15 with respect to the swing arm 14 are: Since it is set to be located on the same side of the swing arm 14 with respect to the control shaft 13, that is, on the other end side of the swing arm 14, the swing arm 14 is pulled down by the drive cam 112 to operate the valve. The link arm 12 is lifted, and a load in the pulling direction acts on the link arm 12.

  Hereinafter, for convenience of explanation, the same constituent elements as those in the first embodiment are denoted by the same reference numerals, and redundant description is omitted.

  This will be described in detail with reference to FIG. FIG. 5 (A-1) shows the link when the valve is opened in the variable valve mechanism of the type (normal link) in which the pin member 21 and the pin 22 are located on the opposite side across the control shaft 13. FIG. 5 (A-2) is a front view of a variable valve mechanism for a normal link. FIG. 5B-1 shows a variable motion of a type (down link) in which the pin member 21 and the pin 22 are located on the same side with respect to the control shaft 13 as in the variable valve mechanism of the first embodiment described above. FIG. 5B is a side view showing the state of the link when the valve is opened in the valve mechanism, and FIG. 5B-2 is a front view of the variable valve mechanism of the pull-down link. 5A-1, 5A-2, 5B-1, and 5B-2, the same components as those in the first embodiment are described for convenience of explanation. Are denoted by the same reference numerals, and redundant description will be omitted.

  In the variable valve mechanism of the type in which the pin member 21 and the pin 22 are located on the opposite sides across the control shaft 13 as shown in FIG. 5 (A-1) and FIG. When the valve opens, the load acts as follows. That is, when the drive shaft 11 rotates and the cam body 112 a rises, the position of the pin member 21 also rises via the link arm 12. Then, the position of the pin 22 is lowered via the swing arm 14. Then, the swing cam 16 is pushed down via the link rod 15 and the valve is opened. When the valve is thus opened, as shown in FIG. 5A-1, a load acts on the link arm 12 in the compression direction, and an upward load acts on both ends of the swing arm 14. . Since a load in the same direction acts on both ends of the swing arm 14, the moment Mx1 generated in the swing arm 14 is a moment that tilts the swing arm 14, as shown in FIG. As does not work.

  On the other hand, a variable valve mechanism of the type in which the pin member 21 and the pin 22 are located on the same side with respect to the control shaft 13 as shown in FIGS. 5 (B-1) and 5 (B-2). In, the load acts as follows when the valve is opened. That is, when the drive shaft 11 rotates and the cam body 112a descends, the position of the pin member 21 also descends via the link arm 12. Then, the position of the pin 22 is also lowered via the swing arm 14. Then, the swing cam 16 is pushed down via the link rod 15 and the valve is opened. When the valve is thus opened, a load acts on the link arm 12 in the pulling direction as shown in FIG. 5 (B-1), and the swing arm as shown in FIG. 5 (B-2). A downward load acts on one end portion along the control axis direction of the control shaft 14, but an upward load acts on the other end portion along the control axis direction of the swing arm 14.

Therefore, a contact load is generated on the link arm 12 on the upper side of the small end portion 12b and on the lower side of the large end portion 12a. Therefore, the small end portion inner peripheral surface 34 and the pin member 21 do not contact evenly along the circumferential direction of the small end portion inner peripheral surface 34. Further, the large end inner peripheral surface 33 and the drive cam 112 do not contact evenly along the circumferential direction of the large end inner peripheral surface 33. Specifically, clearance is easily formed on the large end portion 12a side on the small end inner peripheral surface 34, and clearance is easily formed on the small end portion 12b side on the large end inner peripheral surface 33 . Their to, since the load is applied in the opposite direction at both ends along the control axis direction of the swing arm 14, as shown in FIG. 5 (B-2), large moment that beat swing arm 14 Mx2 Will occur. In the variable valve mechanism of the type in which the pin member 21 and the pin 22 are located on the same side with respect to the control shaft 13, if the distance between the loads is made as small as possible to reduce the moment arm length, The moment for tilting the moving arm 14 can be kept small. In other words, it is possible to reduce the moment of tilting the swing arm 14 by reducing the distance between the pin member 21 and the pin 22, that is, the distance between the link arm 12 and the link rod 15. In other words, it is possible to keep the moment of tilting the swing arm 14 small by bringing the point of application of the load acting on the swing arm 14 from the link arm 12 closer to the center of the swing arm 14 in the control axis direction.

  Here, as shown in FIG. 6, it can be seen that the link arm 12 having the shape used in the first embodiment has a high rigidity in the compression direction and a low rigidity in the tensile direction. That is, in the variable valve mechanism of the “pull-down link” such as the valve gear 10 in the first embodiment described above, when a large load is applied to the link arm 12, the variable valve mechanism of the “normal link” is compared. The link arm 12 is greatly deformed.

  FIG. 7 is an explanatory view showing the result of examining the deformation state when a tensile load is applied to the link arm 12 having the shape used in the first embodiment by the finite element method.

  As shown in FIG. 7, when a tensile load is applied, the large end portion 12a of the link arm 12 is remarkably deformed, and a clear close-in (a phenomenon in which the diameter is narrowed and wound around the shaft) appears. This occurs because the tensile stiffness of the large end portion 12a is significantly smaller than the tensile stiffness of the small end portion 12b and the linkage portion 12c of the link arm 12. If the tensile rigidity of the link arm link portion 12c is not relatively large (small) with respect to the large end, the link portion 12c is stretched and deformed, while the close-in is alleviated.

  Among the sliding parts of the variable valve operating apparatus as in the first embodiment, the largest PV value (P: surface pressure, V: sliding speed) is the large end 12a, that is, the link arm 12 and It is a sliding surface with the drive cam 112, and there is a risk of causing sliding troubles such as seizure, triggered by the close-in.

  In contrast, the valve gear 10 for the engine according to the first embodiment described above is provided with the lift adjustment mechanism 41 that holds the pin member 21 with the pair of screw members 44 and 45 in the link arm 12 and the link arm 12. The following effects are obtained by removing the thickness of the linkage portion 12c.

  That is, by providing the lift adjustment mechanism 41, the first screw member 44 and the second screw member 45 can be turned to change the position of the first rotation fulcrum, and the valve lift amount of the valve gear 10 can be adjusted. The valve device 10 can be finely adjusted without disassembling.

  Further, by reducing the weight of the link arm 12 by reducing the thickness of the linkage portion 12c, it is possible to absorb the increase in mass corresponding to the provision of the lift adjustment mechanism 41 and reduce the moment of inertia of the valve gear 10 as a whole.

  Since the link portion 12c of the link arm 12 is thinned by providing the through hole 42, and the rigidity of the link portion 12c is slightly reduced, the close-in of the link arm 12 can be mitigated.

  The first rotation fulcrum that links the link arm 12 and the swing arm 14 and the second rotation fulcrum that links the swing arm 14 and the link rod 15 are on the same side with respect to the control shaft 13. In the case of the valve gear 10 configured to be positioned, the seizure of the close-in increases the seizure limit between the link arm 12 and the drive cam 112, and in combination with the effect of reducing the moment of inertia, further engine height increases. Rotation is possible.

  As shown in FIGS. 8 and 9, the link arm 12 and the swing arm 14 are connected by a hole formed in the swing arm 14 with a pin member 21 that is a supported member protruding from the link arm side. Therefore, the point of application of the load acting on the swing arm 14 from the link arm 12 can be made closer to the center of the swing arm 14 in the control axis direction. Therefore, as in the first embodiment described above, the linkage point between the link arm 12 and the swing arm 14 (first rotation fulcrum) and the link point between the swing arm 14 and the link rod 15 (second In the valve operating apparatus 10, the tilting moment of the swing arm 14 caused by the load acting on the swing arm 14 from the link arm 12 is configured so that the rotation fulcrum) is located on the same side with respect to the control shaft 13. Can be greatly reduced, and as a whole, the falling moment of the entire swing arm 14 can be greatly reduced.

  Further, as shown in FIG. 9, the axis of the bolt 38, the center line of the load acting from the link rod 15 (the center line of the width of the link rod 15 in the control axis direction), and the action of the load acting from the pin member 21. If the points are set so as to substantially match in the control axis direction, the action lines of all external forces acting on the swing arm 14 will match in the control axis direction. The falling moment acting on the can be minimized.

  Hereinafter, other embodiments of the present invention will be described. However, for convenience of explanation, the same components as those in the first embodiment are denoted by the same reference numerals, and redundant description will be omitted.

  A second embodiment of the present invention will be described with reference to FIGS. The second embodiment has substantially the same configuration as that of the first embodiment described above, but in the link portion 12c of the link arm 12, a receiving hole in which the second screw member 45 is received instead of the through hole 42. 51 is formed. The accommodation hole 51 is opened to the inner peripheral surface of the small end portion 12 b, and the inner peripheral surface is a female screw portion 43 b that is screwed into the second screw portion 45.

  The link arm 12 is formed with an oil hole 52 that communicates the sliding surface between the drive cam 112 and the large end portion 12a and the accommodation hole 51 of the linkage portion 12c.

  The second screw member 45 is formed with a screw member through hole 53 extending along the axial direction of the second screw member 45. A part of the screw member through hole 53 serves as a tool engagement portion 54 having the same cross-sectional shape (for example, hexagonal shape) as that of the spanner used when the second screw member 45 is rotated. A portion 54 is formed to engage with the spanner. In the second embodiment, a tool engaging portion 54 having a hexagonal cross section is formed on one end side of the screw member through hole 53.

  In the second embodiment, a spanner is inserted into the screw member through hole 53 from the small end portion 12b side, and the second screw member 45 is rotated until the second screw member 45 reaches a desired position.

  In such a second embodiment, in addition to the effects of the first embodiment described above, since the accommodation hole functions as an oil sump, it is possible to improve the lubricity particularly at the time of starting the engine.

  The lubricating oil supplied to the sliding surface between the drive cam 112 and the large end portion 12 a is temporarily stored in the accommodation hole 51 through the oil hole 52.

  Therefore, even if a long time elapses after the engine is stopped, the lubricating oil in the accommodation hole 51 can be supplied to the sliding surface between the link arm 12 and the drive cam 112 via the oil hole 52. Oil shortage on the sliding surface with the cam 112 can be suppressed.

  Further, since the screw member through hole 53 is formed in the second screw member 45, the lubricating oil supplied to the sliding surface between the link arm 12 and the drive cam 112 is supplied with the oil hole 52, the accommodation hole 51, and the screw member through hole. A lubricating oil path that leads to the pin member 21 via 53 can be configured, and the pin member 21 can be lubricated.

  A third embodiment of the present invention will be described with reference to FIGS. The third embodiment has substantially the same configuration as the second embodiment described above, but the supported member sandwiched between the pair of screw members 44 and 45 is a cylindrical tubular member 61 and swings. The arm 14 is provided with a pin portion 62 that is rotatably fitted to the inner peripheral surface of the cylindrical member 61.

  As shown in FIG. 17, the cylindrical member 61 has a planar seat surface 63 formed on a portion of the outer peripheral surface that is sandwiched between the first screw member 44 and the second screw member 45.

  In the third embodiment as well, as in the first embodiment, it is possible to reduce the polar moment of inertia of the valve operating apparatus 10 as a whole, to ease the close-in of the link arm 12, and to further increase the engine speed. Become.

  In general, the linkage between the link arm and the swing arm is configured such that the pin-like member protruding from the swing arm side is rotatably fitted in the hole on the link arm side. Therefore, as in the third embodiment, if the link arm and the swing arm are linked, it is possible to provide a lift adjustment mechanism by changing the design of only the link arm. On the other hand, the lift adjustment mechanism can be provided with a small design change.

  In the second and third embodiments described above, the main oil passage of the drive shaft 11 is obtained by using the screw member through hole 53 of the second screw member 45 as an oil passage as shown in FIGS. The supported oil 21, 31 can be guided to the supported members 21, 61 that are in contact with the second screw member 45, and the supported members 21, 61 can be lubricated.

  That is, the main oil passage 31, the oil supply hole 71 formed in the drive shaft main body 111, the oil supply hole 72 formed in the drive cam 112, the oil hole 52, the accommodation hole 51, and the screw member through hole 53, the lubricating oil continues. A supply path can be formed.

  The technical ideas of the present invention that can be grasped from the above-described embodiments will be listed together with their effects.

  (1) A drive shaft that rotates in synchronization with engine rotation, a drive cam provided on the drive shaft, a link arm that is fitted to the outer periphery of the drive cam so as to be relatively rotatable, and provided in parallel with the drive shaft And a rotatable control shaft having a main shaft portion and an eccentric cam portion, and a swing mounted rotatably on the eccentric cam portion of the control shaft and linked to the link arm via a first rotation fulcrum An arm, a link rod linked to the rocking arm via a second rotation fulcrum, and the link rod connected to the rocking arm via the link rod. A rocking cam that presses the valve, and the link arm is fitted to the outer periphery of the drive cam so as to be relatively rotatable, and is relatively fitted to the outer periphery of the first rotation fulcrum. A small end portion, the large end portion and the small end portion In the engine valve mechanism, the link arm is capable of adjusting a lift amount of the valve by changing a position of the first rotation fulcrum. The lift adjusting mechanism includes a pair of screw members that are respectively screwed into female screw portions formed on the link arm, and a supported portion that is sandwiched in the small end portion of the link arm by the pair of screw members. And the position of the first rotation fulcrum can be changed by changing the position of the supported member held in the small end portion.

  When the position of the first rotation fulcrum is changed, the length of the link arm is substantially changed. Accordingly, by turning the pair of screw members and changing the position of the first rotation fulcrum, the lift amount of the valve can be finely adjusted without disassembling the valve device. Further, by providing the link arm with the lift adjustment mechanism, the inertial mass of the swing arm can be reduced as compared with the case where the lift adjustment mechanism is provided on the swing arm. Therefore, the polar moment of inertia of the swing arm is reduced, and as a result, the polar moment of inertia of the entire valve operating apparatus can be relatively reduced.

  (2) In the engine valve operating apparatus according to (1), the supported member is a pin member that has a cylindrical shape and a tip projects from a link arm, and the pin member is formed by the swing arm. It is rotatably supported. Accordingly, the supported member serves as a first rotation fulcrum and is rotatably supported by the swing arm. Therefore, since the supported member protruding from the link arm side is rotatably supported by the swing arm, the link arm and the swing arm are linked, so that the load acting on the swing arm from the link arm The point can be brought close to the center of the swing arm in the control axis direction. As a result, the tilting moment of the swinging arm due to the load acting on the swinging arm from the link arm can be greatly reduced, and the tilting moment of the entire swinging arm can be greatly reduced as a whole.

  (3) In the valve gear for an engine according to (1), the supported member is a cylindrical member having a cylindrical shape, and the swinging arm is rotatably fitted to the supported member. A pin portion is provided. A pin portion of a swing arm serving as a first rotation fulcrum is rotatably fitted to the supported member. In general, the linkage between the link arm and the swing arm is such that a pin-like member protruding from the swing arm side is rotatably fitted in the hole on the link arm side. As a result, the lift adjustment mechanism can be provided only by changing the design of the link arm. Therefore, it is possible to provide the lift adjustment mechanism with little design change with respect to the existing valve gear.

  (4) In the engine valve operating device according to any one of (1) to (3), specifically, the first rotation fulcrum and the second rotation fulcrum are in relation to the control shaft. Located on the same side.

  (5) In the engine valve operating apparatus according to (4), the linkage portion is provided with a through hole along the axial direction of the supported member, and the linkage portion is thinned by the through hole. ing. Thereby, the weight of the link arm is relatively reduced, and the increase in weight due to the provision of the lift adjustment mechanism can be absorbed. In the link arm, the rigidity balance between the small end portion and the large end portion is improved, and close-in due to deformation of the large end portion can be prevented.

  (6) In the valve operating apparatus for an engine according to any one of (1) to (4), the linkage portion is open to an inner peripheral surface of a small end portion, and one of the pair of screw members. A housing hole is formed, the female thread portion is formed on the inner peripheral surface of the housing hole, and the linkage portion is thinned by the housing hole. Thereby, the weight of the link arm is relatively reduced, and the increase in weight due to the provision of the lift adjustment mechanism can be absorbed. Further, the accommodation hole becomes a pool of oil, and the lubricity at the time of starting the engine can be improved.

(7) In the valve gear for an engine according to (6), an oil hole that communicates the sliding surface between the drive cam and the large end portion and the accommodation hole of the linkage portion is formed in the link arm. Is formed. As a result, the lubricating oil supplied to the sliding surface between the drive cam and the large end is temporarily stored in the accommodation hole through the oil hole. Therefore, even if a long time elapses after the engine is stopped, the lubricating oil in the accommodation hole can be supplied to the sliding surface of the link arm and the drive cam via the oil hole. Oil shortage on the sliding surface with the cam can be suppressed.

(8) In the valve gear for an engine according to (7), a screw member through-hole along the axial direction of the screw member is formed through the screw member accommodated in the accommodation hole . Thus, a lubricating oil path is formed that guides the lubricating oil supplied to the sliding surfaces of the link arm and the drive cam to the supported member through the oil hole, the accommodation hole, and the screw member through hole. And even the supported member can be lubricated.

DESCRIPTION OF SYMBOLS 10 ... Valve operating apparatus 12 ... Link arm 21 ... Pin member 41 ... Lift adjustment mechanism 43a ... Female screw part 43b ... Female screw part 44 ... First screw member 45 ... Second screw member

Claims (7)

A drive shaft that rotates in synchronization with engine rotation; a drive cam provided on the drive shaft; a link arm that is fitted to the outer periphery of the drive cam so as to be relatively rotatable; and provided in parallel with the drive shaft; A rotatable control shaft having a main shaft portion and an eccentric cam portion, and a swinging arm rotatably mounted on the eccentric cam portion of the control shaft and linked to the link arm via a first rotation fulcrum; A link rod linked to the swing arm via a second rotation fulcrum, and connected to the swing arm via the link rod, and presses the valve by swinging with the swing arm. And a swing cam that
The link arm has a large end that is fitted to the outer periphery of the drive cam so as to be relatively rotatable, a small end that is fitted to the outer periphery of the first rotation fulcrum so as to be relatively rotatable, the large end, In a valve operating apparatus for an engine having a small end portion and a linking portion connecting the two,
The link arm has a lift adjustment mechanism that can adjust a lift amount of the valve by changing a position of the first rotation fulcrum,
The lift adjusting mechanism includes a pair of screw members that are respectively screwed into female screw portions formed on the link arm, and a supported member that is sandwiched in the small end portion of the link arm by the pair of screw members. Provided, the position of the first rotation fulcrum can be changed by changing the position of the supported member sandwiched in the small end ,
A valve operating device for an engine according to claim 1, wherein a through hole along the axial direction of the supported member is provided in the linkage portion, and the linkage portion is thinned by the through hole . A drive shaft that rotates in synchronization with engine rotation; a drive cam provided on the drive shaft; a link arm that is fitted to the outer periphery of the drive cam so as to be relatively rotatable; and provided in parallel with the drive shaft; A rotatable control shaft having a main shaft portion and an eccentric cam portion, and a swinging arm rotatably mounted on the eccentric cam portion of the control shaft and linked to the link arm via a first rotation fulcrum; A link rod linked to the swing arm via a second rotation fulcrum, and connected to the swing arm via the link rod, and presses the valve by swinging with the swing arm. And a swing cam that
The link arm has a large end that is fitted to the outer periphery of the drive cam so as to be relatively rotatable, a small end that is fitted to the outer periphery of the first rotation fulcrum so as to be relatively rotatable, the large end, In a valve operating apparatus for an engine having a small end portion and a linking portion connecting the two,
The link arm has a lift adjustment mechanism that can adjust a lift amount of the valve by changing a position of the first rotation fulcrum,
The lift adjusting mechanism includes a pair of screw members that are respectively screwed into female screw portions formed on the link arm, and a supported member that is sandwiched in the small end portion of the link arm by the pair of screw members. Provided, the position of the first rotation fulcrum can be changed by changing the position of the supported member sandwiched in the small end ,
The linking portion has an opening formed on the inner peripheral surface of the small end portion, and a receiving hole for receiving one of the pair of screw members is formed. The female screw portion is formed on the inner peripheral surface of the receiving hole. In addition, the valve operating device for an engine is characterized in that the connecting portion is cut out by the accommodation hole . 3. The engine according to claim 2 , wherein an oil hole is formed in the link arm to communicate the sliding surface between the drive cam and the large end portion and the accommodation hole of the linkage portion. Valve operating device. The valve operating device for an engine according to claim 2 or 3 , wherein the screw member accommodated in the accommodation hole has a threaded member through hole extending in the axial direction of the screw member. The supported member is a pin member that has a cylindrical shape and has a tip protruding from a link arm,
The engine valve operating device according to any one of claims 1 to 4, wherein the pin member is rotatably supported by the swing arm. The supported member is a cylindrical member having a cylindrical shape,
The valve operating apparatus for an engine according to any one of claims 1 to 4, wherein the swing arm is provided with a pin portion that is rotatably fitted to the supported member. The valve operating apparatus for an engine according to any one of claims 1 to 6 , wherein the first rotation fulcrum and the second rotation fulcrum are located on the same side with respect to the control shaft.

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