JP4212543B2 - Valve operating device for internal combustion engine - Google Patents

Description

  The present invention relates to a valve operating apparatus for an internal combustion engine capable of adjusting, for example, a valve lift amount of an intake valve when assembling each component member.

  As this type of conventional valve gear, there is one described in the following Patent Document 1 previously filed by the present applicant.

  Briefly, this valve operating device is applied to the intake valve side, and is driven in such a manner that the shaft center is eccentric from the shaft center of the drive shaft on the outer periphery of the drive shaft rotating in synchronization with the rotation of the crankshaft. A cam is provided, and the rotational force of the drive cam is transmitted through a multi-link transmission mechanism, and the cam surface slides on the upper surface of the valve lifter at the upper end of the intake valve to control the intake valve. It has a swing cam that opens against the spring force of the spring.

  The transmission mechanism includes a rocker arm that is disposed above the swing cam and is swingably supported by the control shaft, an annular one end is fitted to the outer peripheral surface of the drive cam, and the other end is one end of the rocker arm. A link arm that is rotatably connected to the part via a pin, one end part is rotatably connected to the other end part of the rocker arm via a pin, and the other end part is connected to the cam nose part of the swing cam via a pin. And a link rod connected rotatably.

  The control shaft is rotatably supported by a bearing provided at the upper end of the cylinder head, and a control cam whose shaft center is eccentric from the control shaft axis by a predetermined amount is fixed to the outer peripheral surface thereof. Has been.

  Then, the swing fulcrum of the rocker arm is changed by changing the rotational position of the control cam through the control shaft by an actuator composed of an electric motor, screw transmission means, etc. according to the engine operating state, and The rolling contact position of the cam surface with respect to the upper surface of the valve lifter is changed to variably control the valve lift amount of the intake valve according to the engine operating state.

  In addition, such a valve operating apparatus requires many components such as the transmission mechanism using a multi-joint link mechanism, and due to these manufacturing errors and assembly errors, each intake valve Variations in the valve lift amount are likely to occur, and in particular, variations in the valve lift amount among the cylinders are likely to occur.

Therefore, in this conventional valve operating apparatus, after the components such as the transmission mechanism are assembled on the cylinder head by attaching the valve spring to the drive shaft or the control shaft in the radial direction, the bearing member is mounted. The valve lift amount of each intake valve is adjusted by removing the respective pins, replacing the link rods, and changing their lengths.
JP 2001-123809 A

  However, in the conventional valve operating apparatus, in order to adjust the length of the link rod, the link rod is once assembled to a rocker arm or a swing cam, and the valve lift amount is measured. Must be removed from the side of the link rod using a tool, another link rod with a different length must be selected, and each pin must be inserted again from the side and connected.

  Therefore, the lift adjustment work becomes complicated, and in particular, since each pin has to be inserted and removed from the side of the link rod with a narrow space by using a tool, the insertion and removal work becomes complicated and the lift adjustment work efficiency is increased. The decline and cost increase are forced.

  The present invention has been devised in view of the technical problem of the conventional variable valve operating apparatus. The invention according to claim 1 is driven to rotate by the crankshaft of an engine, and a drive eccentric cam is integrated on the outer periphery. A fixed drive shaft, a swing cam for opening and closing the engine valve, and a rotational motion of the drive eccentric cam transmitted via the drive shaft is converted into a swing motion and transmitted to the swing cam. A transmission mechanism, a link member that constitutes a part of the transmission mechanism and that is swingably provided with a support pin inserted into a pin hole on one end side as a fulcrum; and a predetermined member to which the support pin is fixed The support pin is fixed to the predetermined member by a fixing member that is provided and is inserted through a fixing hole that opens toward the upper side in the direction of gravity, and an adjustment shim is sandwiched between the predetermined member and the support pin. Lift adjuster configured as follows It is characterized by comprising and.

  According to this invention, when assembling each component member, in order to adjust the valve lift amount of the engine valve, first, an optimum adjustment shim is selected and placed between the predetermined member and the support pin, and then Since the fixing member is simply inserted into the fixing hole from above in the direction of gravity and the adjustment shim is simply held between the predetermined member and the support pin, the adjustment work of the valve lift amount is facilitated.

  According to a second aspect of the present invention, a drive shaft that is rotationally driven by an engine crankshaft and has a drive eccentric cam integrally fixed to the outer periphery thereof, a swing cam that opens and closes an engine valve, and the drive shaft A transmission member that converts the rotational motion of the drive eccentric cam transmitted to the rocking motion, a rocker arm that rocks freely with a rocker shaft as a fulcrum, and a rocking force transmitted from the transmission member, and the rocker arm An integrally provided arm portion that swings in synchronization with the rocking motion of the rocker arm, a link member that transmits the rocking motion of the arm portion to the rocking cam, and fixed to the arm portion. A support pin serving as a swing fulcrum of the link member, and a pin insertion hole that is provided in each of the arm portions and through which the support pin can be inserted. A fixing hole oriented in the direction, a shim insertion hole formed orthogonal to the pin insertion hole and the fixing hole, a fixing member inserted through the fixing hole and abutting on the support pin from an orthogonal direction, An adjustment shim is provided which is inserted into the shim insertion hole and is sandwiched between the support pin and the inner peripheral surface of the shim insertion hole.

  According to the present invention, when adjusting the valve lift of the engine valve when assembling each component of the valve gear, first, for example, a reference adjustment shim is previously placed in the shim insertion hole of the arm portion. The support pin is inserted through the pin insertion hole and the pin hole of the link member.

  Thereafter, a fixing member is inserted through the fixing hole, and the support pin is pressed toward the adjustment shim by the fixing member, so that the adjustment shim is held between the inner peripheral surface of the shim insertion hole and the support pin. To do.

  In this state, the valve lift amount of the engine valve is measured. If the desired lift is not achieved, another appropriate adjustment shim having a different thickness width is selected and reassembled. In this way, the valve lift is adjusted to a desired amount, but such adjustment work is performed without removing all of the lift adjustment mechanism, and the fixing member is performed from above in the direction of gravity with respect to the fixing hole. This makes it easy to adjust the valve lift.

  According to a third aspect of the present invention, there is provided a drive shaft that is rotationally driven by an engine crankshaft and has a drive eccentric cam integrally fixed on the outer periphery thereof, a swing cam that opens and closes an engine valve, and the drive shaft. The transmission mechanism that converts the rotational motion of the drive eccentric cam transmitted to the swing cam and transmits it to the swing cam, and the support that is part of the transmission mechanism and that is inserted into the pin hole on one end side. A link member that is swingably provided with a pin as a fulcrum, and an engagement portion that engages with an adjustment female screw hole formed in a predetermined member to which the support pin is fixed, and engages with a tool that applies a rotational force. And an adjustment screw member having a fitting portion that is provided in the predetermined member so as to be freely screwed into a fixing female screw hole formed on the upper side in the direction of gravity, and into which a tool for applying a rotational force is fitted. And the support pin between the adjustment screw member A fixing screw member that can be held, and an axial direction of the fixing screw member and a radial direction of the support pin, which are continuously penetrated, facing the engaging portion of the adjustment screw member, and from above the fixing screw member And a tool insertion portion for engaging a tip end portion of the inserted tool with an engagement portion of the adjustment screw member.

  According to this invention, in order to adjust the valve lift amount of the engine valve, the valve lift amount of the engine valve is measured in a state where the respective constituent members are assembled in advance.

  At this time, if the valve lift amount deviates from the reference value, the fixing screw member is loosened by a tool, and a tool insertion portion of the fixing screw member, that is, a wrench or the like from the upper side in the gravity direction is used. While inserting the tool, the tip of the wrench is engaged with the engaging portion of the adjusting screw member, and the adjusting screw member is rotated to the left or right.

  Accordingly, the position of the support pin in the longitudinal direction of the link member is changed and the length of the link member is substantially changed, so that the valve lift amount can be adjusted.

  After the valve lift amount is determined, when the fixing screw member is tightened with a predetermined tool such as a spanner, the support pin is fixed in a sandwiched state between the fixing screw member and the adjusting screw member. The adjustment of the lift amount is completed.

  As described above, in the present invention, the valve lift amount can be adjusted from the upper side of the gravity as well as the valve lift amount can be adjusted in a state where the respective components are assembled. Adjustment work becomes easier.

  Hereinafter, embodiments of a valve operating apparatus for an internal combustion engine according to the present invention will be described in detail with reference to the drawings. In this embodiment, a variable mechanism that is applied to the intake valve side of a multi-cylinder internal combustion engine, includes two intake valves per cylinder, and makes the valve lift of the intake valve variable according to the engine operating state. I have.

  As shown in FIGS. 4 to 7, the valve operating apparatus in this embodiment includes a pair of intake valves 2 and 2 per cylinder that are slidably provided on a cylinder head 1 via a valve guide (not shown), an engine, An internal hollow drive shaft 3 disposed in the front-rear direction, a camshaft 4 disposed for each cylinder and supported coaxially and rotatably on the outer peripheral surface of the drive shaft 3, The drive cam 5 integrally fixed at a predetermined position and the valve lifters 6, 6 provided integrally at both ends of the camshaft 4 and disposed at the upper ends of the intake valves 2, 2 are slid. A pair of oscillating cams 7, 7 that are in contact with each other to open the intake valves 2, 2 and the drive cam 5 and the oscillating cams 7, 7 are linked to each other, and the rotational force of the drive cam 5 is oscillated. 7. A transmission mechanism 8 that transmits as a swinging force (valve opening force) 7 and 7 and an operating position of the transmission mechanism 8 are made variable. And a control mechanism 9.

  The intake valves 2 and 2 are closed in a closing direction by valve springs 10 and 10 mounted between a bottom portion of a substantially cylindrical bore housed in an upper end portion of the cylinder head 1 and a spring retainer at the upper end portion of the valve stem. It is energized.

  The drive shaft 3 is disposed along the longitudinal direction of the engine, and both ends thereof are rotatably supported by bearings (not shown) provided at the top of the cylinder head 1 and are also provided at one end. Rotational force is transmitted from the crankshaft of the engine via an external driven sprocket and a timing chain wound around the driven sprocket.

  The camshaft 4 is formed in a substantially cylindrical shape along the axial direction of the drive shaft 3, and a support shaft hole that is rotatably supported on the outer peripheral surface of the drive shaft 3 is formed through the inner shaft direction. A large-diameter cylindrical journal portion 4a formed at the center position is rotatably supported by a cam bearing (not shown).

  The drive cam 5 is formed in a substantially disc shape, and a fixing cylindrical portion is integrally provided on one side thereof, and this cylindrical portion is fixed at a predetermined position in the axial direction of the drive shaft 3. The pin 12 is integrally fixed to the outer periphery of the drive shaft 3, and the outer peripheral surface is formed in an eccentric cam profile, so that the shaft center Y is a predetermined amount in the radial direction from the shaft center X of the drive shaft 3. Is just offset.

  Each of the swing cams 7 has a substantially raindrop shape with the same shape, and the base end side swings about the axis X of the drive shaft 3 via the cam shaft 4 and swings. On the lower surface of the cam 7, cam surfaces that are in contact with predetermined positions on the upper surface of each valve lifter 6 are formed.

  The transmission mechanism 8 includes a rocker arm 13 disposed above the drive shaft 3, a link arm 14 linking the one end 13 a of the rocker arm 13 and the drive cam 5, and the other end 13 b of the rocker arm 13. A link rod 15 that is a link member that links the cam nose portion of the moving cam 7 is provided.

  As shown in FIGS. 1 to 3, the rocker arm 13 has a support hole 13c penetratingly formed in a central cylindrical base from the lateral direction, and swings to a control cam 26 described later via the support hole 13c. It is supported freely. One end 13a of the rocker arm 13 is integrally provided with a pin 27 on the side of the tip, while the other end 13b, which is an arm, is connected to the link rod 15 on the tip. A lift adjustment mechanism 16 for adjusting the valve lift amount of the intake valves 2 and 2 is provided.

  The link arm 14 includes a large-diameter annular portion 14a and a projecting end 14b projecting at a predetermined position on the outer peripheral surface of the annular portion 14a. The drive cam is located at the center of the annular portion 14a. A fitting hole 14c is formed in the outer peripheral surface of the pin 5 so as to be freely rotatable, and a pin hole through which the pin 27 is rotatably inserted is formed in the protruding end 14b.

  The link rod 15 is formed in a substantially U-shaped cross section by press molding, and the inner side is bent in a substantially U-shape for compactness, and has a parallel two-plate shape. Pin holes 15c and 15d are formed in both end portions 15a and 15b so as to penetrate in the lateral direction.

  The link rod 15 is rotatably linked to the cam nose portion of the swing cam 7 via a pin 21 having the other end portion 15b inserted through the pin hole 15d, while the one end portion 15a is connected to the pin hole 15c. The other end portion 13 b of the rocker arm 13 is linked via the support pin 20 inserted through the lift pin and the lift adjusting mechanism 16.

  The lift adjusting mechanism 16 is formed in a substantially rectangular block-like linkage portion 17 integrally provided at the tip of the other end portion 13b of the rocker arm 13 and is formed from the upper surface in the gravity direction of the linkage portion 17 to be fixed. A fixing female screw hole 19 into which a fixing screw member 18 as a member is screwed from above, and a through hole formed in a direction orthogonal to the female screw hole 19 from both side surfaces of the linkage portion 17, and the support pin 20 is inserted. A pin insertion hole 22 and a shim that is drilled in the direction perpendicular to the female screw hole 19 and the pin insertion hole 22 in the axial direction of the rocker arm 13 from the front surface side of the linking part 17, and an adjustment shim 23 is inserted therein. An insertion hole 24 is provided.

  The fixing screw member 18 has a male screw formed on the outer periphery of a shaft portion 18b integrally formed on the lower surface of the hexagonal head portion 18a, and a tip surface 18c of the shaft portion 18b is formed in a flat surface.

  The support pin 20 has a flat surface portion 20c on the outer peripheral edge of the shaft portion 20b integrally formed with the flange-shaped head portion 20a, in which the front end surface 18c of the fixing screw member 18 abuts in a surface contact state. A notch portion 20d is formed at the outer peripheral edge position corresponding to the flat portion 20c of the portion 20a as a guide for aligning the flat portion 20c in the opening direction of the female screw hole 19 when the pin insertion hole 22 is inserted. ing.

  The pin insertion hole 22 is formed in a substantially elliptical long hole that is long in the vertical direction, and the inserted support pin 20 is slightly movable in the vertical direction during lift adjustment.

  The shim insertion hole 24 is formed in a substantially cylindrical shape with a bottom, the formation position thereof is located below the linkage portion 17, and the lower end edge is formed at a position lower than the lower end edge of the pin insertion hole 22. ing.

  In the adjustment shim 23, a cylindrical pin is formed in a halved shape from the vertical direction, and the upper surface 23a is formed in a flat surface shape, while the lower surface 23b contacting the lower end surface of the pin insertion hole 22 is an arc surface. It is formed in a shape. Further, an arcuate surface 23c is formed on the distal end side of the upper surface 23a so that the arcuate lower surface of the pin shaft portion 20b comes into contact with the surface when in contact with the shim insertion hole 24.

  Further, the length of the adjusting shim 23 is set to be greater than the depth of the shim insertion hole 24, and the adjustment shim 23 is formed so that the front end projecting from the shim insertion hole 24 can be gripped and exchanged easily. ing. A plurality of adjustment shims 23 having different depths of the circular arc surface 23c are prepared in advance.

  As shown in FIGS. 4 to 7, the control mechanism 9 includes a control shaft 25 disposed above the drive shaft 3, and a swing fulcrum of the rocker arm 13 that is integrally fixed to the outer periphery of the control shaft 25. And a non-illustrated actuator for controlling the rotation of the control shaft 25.

  The control shaft 25 is arranged in the longitudinal direction of the engine in parallel with the drive shaft 3, and is rotatably supported by a bracket provided at the upper end of a bearing (not shown). On the other hand, the control cam 26 has a cylindrical shape, and the axial center position is deviated from the axial center of the control shaft 25 by a predetermined amount by the thick portion.

  The actuator includes an electric motor (not shown) fixed to the rear end of the cylinder head 1 and screw transmission means for transmitting the rotational driving force of the electric motor to the control shaft 25.

  The electric motor is constituted by a proportional DC motor, and is driven by a control signal from a controller (not shown) that detects the operating state of the engine. This controller includes various sensors such as a crank angle sensor that detects the engine speed, an air flow meter that detects the intake air amount, a water temperature sensor that detects the engine water temperature, and a potentiometer that detects the rotational position of the control shaft 25. The detection signal is fed back to detect the current engine operating state by calculation or the like, and a control signal is output to the electric motor.

  Hereinafter, the variable action of the valve lift amount according to the present embodiment will be briefly described with reference to FIGS.

  First, for example, in a low rotation range of the engine, when the electric motor is rotationally driven by the controller and this rotational torque is transmitted to the screw transmission means and rotated, the control shaft 25 is rotationally driven in one direction by a predetermined amount. . Therefore, as shown in FIGS. 6A and 6B, the control cam 26 rotates in one direction so that the shaft center rotates around the shaft center of the control shaft 25 with the same radius, and the thick portion 26a is removed from the drive shaft 3. Move away upward. As a result, the other end portion 13b of the rocker arm 13 and the pivot point (support pin 20) of the link rod 15 move upward with respect to the drive shaft 3, so that each swing cam 7 moves the link rod 15 through the link rod 15. The cam nose portion side is forcibly pulled up through.

  Therefore, when the drive cam 5 rotates and pushes up the one end portion 13a of the rocker arm 13 via the link arm 14, the valve lift amount is transmitted to the swing cam 7 and the valve lifter 6 via the link rod 15. The lift amount of the intake valves 2 and 2 is sufficiently small.

  Further, when the engine is shifted to the high engine speed region, when the electric motor is reversely rotated by the controller and the screw transmission means is rotated in the same direction, the control shaft 25 causes the control cam 26 to move along with this rotation, and FIGS. As shown in Fig. 4, the shaft is rotated in the other direction, and the axis moves downward. For this reason, the entire rocker arm 13 is moved in the direction of the drive shaft 3 and the cam nose portion of the rocking cam 7 is pressed downward via the link rod 15 by the other end portion 13b. Turn counterclockwise by a predetermined amount.

Therefore, the contact position of the cam surface with respect to the upper surface of the valve lifter 6 of the swing cam 7 moves to the cam nose portion side (lift portion side).
For this reason, when the drive cam 5 rotates and the one end 13a of the rocker arm 13 is pushed up through the link arm 14 when the intake valve 2 is opened, the valve lift amount of the intake valves 2 and 2 is increased through the valve lifter 6. Become.

  Next, a procedure for adjusting the valve lift amounts of the intake valves 2 and 2 between the cylinders when the components of the valve gear are assembled will be described.

  First, after the components such as the drive shaft 3, the transmission mechanism 8, and the control mechanism 9 are assembled to the cylinder head 1 via cam bearings, the intake valves 2 and 2 between the cylinders at the time of the minimum valve lift are set. The lift amount is checked. At this time, the one end portion 15a of the link rod 15 is lifted and disposed on the linkage portion 17 side of the rocker arm other end portion 13b.

  2 and 3, a reference adjustment shim 23 is inserted in advance in the shim insertion hole 24, and pin holes 15c and 15c of the link rod 15 orthogonal to the shim insertion hole 24 and the linkage portion 17 are orthogonal thereto. The shaft portion 20 b of the support pin 20 is inserted into the pin insertion hole 22, and the arc-shaped lower surface is fitted and disposed on the arc surface 23 c of the adjustment shim 23.

  Thereafter, the fixing screw member 18 is screwed into the female screw hole 19, and the head 18 a is tightened with a tool such as a spanner while the front end surface 18 c is in contact with the flat surface 20 c of the support pin 20. As a result, the support pin 20 is pressed toward the adjustment shim 23, and the adjustment shim 23 is held between the inner peripheral surface of the shim insertion hole 24 and the support pin 20.

  In this state, the valve lift amount of the intake valves 2 and 2 is measured. If the desired lift is not achieved, another appropriate adjustment shim 23 having a different thickness width is selected and reassembled. That is, the fixing screw member 18 is loosened and moved upward, and then the adjustment shim 23 is pulled out while holding the protruding end portion while lifting the support pin 20 upward in the pin insertion hole 22.

  Subsequently, another adjustment shim 23 is inserted into the shim insertion hole 24 in this state, and the fixing screw member 18 is fastened and fixed again. For this reason, the support pin 20 slightly moves up and down in the pin insertion hole 22 by the thickness width of the adjustment shim 23 and is fixed at a predetermined position.

  Thereby, the vertical length of the link rod 15 is substantially changed, and the valve lifts of the intake valves 2 and 2 between the cylinders are adjusted to a uniform and optimum range.

  In this lift adjustment operation, the adjustment shim 23 is inserted / removed from the shim insertion hole 24, that is, from the width direction of the engine without inserting / removing the support pin 20, and the loosening / fastening operation of the fixing screw member 18 is performed by the female screw hole Since the operation can be performed from above in the direction of gravity with respect to 19, the adjustment work of the valve lift amount is facilitated.

  As a result, the length of the link rod 15 is substantially changed by the thickness change of the adjustment shim 23, and the lift amount of each intake valve 2, 2 can be adjusted to a desired optimum size. .

  In this embodiment, the concave arcuate surface 23c of the adjustment shim 23 and the support pin 20 are brought into contact with each other by surface contact. Therefore, even if a load is applied from the support pin 20 to the adjustment shim 23, the surface between the two An increase in pressure can be suppressed. As a result, the so-called sag phenomenon of the contact portion with the adjustment shim 23 is prevented by a large load from the support pin 20, and play between the two can be prevented.

  Further, as described above, in order to ensure surface contact with the adjustment shim 23, there is no need to form a concave arc surface 23c on the adjustment shim 23 and to form a recess on the outer peripheral surface of the support pin 20. A high strength of the support pin 20 can be ensured.

  Furthermore, since both the support pin 20 and the adjustment shim 23 can be fixed simply using the fixing screw member 18, the fixing work is easy and the attaching / detaching work is also easy.

  In addition, in this embodiment, the flat tip end surface 18c of the fixing screw member 18 can be brought into surface contact with the flat portion 20c of the support pin 20, so that a load is applied from the support pin 20 to the fixing screw member 18 during operation. Even if is added, it is possible to sufficiently reduce the surface pressure between the two. For this reason, the contact part of the support pin 20 and the fixing screw member 18 is prevented from being sag, and the occurrence of backlash between them can be suppressed.

  Even if the fixing screw member 18 is inserted into the female screw hole 19 in any direction, the tip end surface 18 c can always be brought into surface contact with the flat portion of the support pin 20.

  Furthermore, since the notch 20d for recognizing the position of the flat surface portion 20c is formed in the head 20a of the support pin 20, when the support pin 20 is inserted into the pin holes 15c, 15c and the pin insertion hole 22, the notch The flat portion 20c can be positioned toward the opening direction of the female screw hole 19 with the portion 20d as a guide. As a result, it is possible to always bring the tip surface 18c of the fixing screw member 18 into contact with the flat surface portion 20c.

  In the present invention, since the minimum valve lift amount of the intake valves 2 and 2 is to be adjusted by the variable lift mechanism, it is possible to reduce the displacement of the valve lift amount as much as possible. Variations in lift amount can be sufficiently prevented.

  8 to 11 show the second embodiment, and the basic structure is substantially the same as that of the first embodiment, except that an adjustment screw member is used instead of the adjustment shim for adjusting the valve lift amount. Is.

  That is, the support pin 20 inserted through the pin insertion hole 22 of the linkage portion 17 is formed in a substantially columnar shape, and is formed with two-sided flat surface portions 20e and 20f on substantially the center side of the upper and lower surfaces. An elliptical groove 20g for recognizing the position of the flat portions 20e and 20f from the outside when the pin insertion hole 22 is inserted into one end face is formed.

  An adjustment female screw hole 30 is formed in the lower end of the linking portion 17 so as to be coaxial with the female screw hole 19, and an adjustment screw member 31 that is screwed into the adjustment female screw hole 30 from below is provided. It has been.

  The adjustment screw member 31 has a substantially cylindrical shape, and has an external thread formed on the outer peripheral surface, and is formed in a flat shape so that the upper surface 31a abuts the lower flat portion 20f of the support pin 20 by surface contact. Has been.

  Further, a tool insertion hole 18d, which is a tool insertion portion through which a tool 33 such as an elongated wrench is inserted in a loosely fitted state, is formed in the vertical direction in the inner axial direction of the fixing screw member 18. On the other hand, there is provided a second tool insertion hole 20h that is formed through substantially at the center of each flat portion 20e, 20f of the support pin 20 and is continuous with the tool insertion hole 18d.

  Further, a flat hexagonal locking portion 31 b with which the tip end portion of each tool 33 engages is formed from the upper surface to the inside of the screw adjusting screw member 31.

  Therefore, according to this embodiment, in order to adjust the minimum valve lift amount of the intake valves 2, 2, the minimum valve lift amount of the intake valves 2, 2 is measured in a state where the respective components are assembled in advance.

  That is, first, the support pin 20 is inserted in advance into the pin holes 15c and 15c of the link rod 15 and the pin insertion hole 22, and the adjustment screw member 31 is screwed into the adjustment female screw hole 30 from below to a predetermined depth. deep. Thereafter, the fixing screw member 18 is screwed into the fixing female screw hole 19 and is tightened through the head 18a by a spanner.

  At this time, the valve lift amount of the intake valves 2 and 2 is measured. If the minimum valve lift amount deviates from the reference value, the fixing screw member 18 is temporarily loosened by a tool.

  Subsequently, as shown in FIG. 10, the tip 33a of the wrench tool 33 is inserted into the tool insertion holes 18d and 20h of the fixing screw member 18 and the pin 20 while the wrench tool 33 is inserted from above in the direction of gravity. Engage with the engaging portion 31a of the adjusting screw member 31, and rotate the wrench tool 33 to rotate the adjusting screw member 31 left or right.

  As a result, the adjustment screw member 31 is slightly moved in either the up or down direction, and thereby the position of the support pin 20 is moved up or down in the pin insertion hole 22.

  As a result, since the position of the support pin 20 in the longitudinal direction of the link rod 15 is changed and the length of the link rod 15 is substantially changed, the minimum valve lift amount of the intake valves 2 and 2 can be finely adjusted. .

  After the valve lift amount is determined, when the fixing screw member 18 is tightened again with a tool such as a spanner, the support pin 20 is fixed in a sandwiched state between the fixing screw member 18 and the adjusting screw member 31. Thereby, the adjustment work of the valve lift amount is completed.

  Thus, in the present embodiment, the valve lift amount can be adjusted from the upper side of the gravity as well as the valve lift amount can be adjusted with the respective components attached. The adjustment work is further facilitated.

  Further, since the fixing screw member 18 and the adjusting screw member 31 are brought into contact with the support pin 20 in a surface contact state by the tip surfaces 18c and 31a and the flat portions 20e and 20f, the surfaces of the respective contact surfaces. Pressure is lowered. As a result, the so-called sag phenomenon of each contact portion is prevented by a large load from the support pin 20 during operation, and play between the two can be prevented.

  The technical ideas other than the invention described in the claims, as grasped from the embodiment, will be described below.

  The valve operating device for an internal combustion engine according to claim 1 or 2, wherein the support pin and the adjustment shim are brought into surface contact with each other.

  Even when a load is applied to the adjustment shim from the support pin during operation of the apparatus, both of them come into contact with each other by surface contact, so that an increase in surface pressure can be suppressed. As a result, a so-called sag phenomenon of the contact portion with the adjustment shim is prevented by a large load from the support pin, and play between the two can be prevented.

  (2) The valve operating apparatus for an internal combustion engine according to (1), wherein an arc-shaped recess along the outer periphery of the support pin is formed on the outer peripheral surface of the adjustment shim.

  Since it is not necessary to form a recess in the outer peripheral surface of the support pin in order to ensure surface contact with the adjustment shim, high strength of the support pin can be ensured.

  (3) While the fixing hole is formed by a female screw hole formed in the predetermined member, the fixing member is formed by a fixing screw member having a male screw portion formed on an outer periphery, and a fixing screw is formed in the female screw hole. 3. The valve operating apparatus for an internal combustion engine according to claim 1, wherein the adjustment shim is sandwiched between a support pin by screwing and fastening a member.

  Since both the support pin and the adjustment shim can be fixed simply using the fixing screw member, the fixing operation is easy and the attaching / detaching operation is also easy.

  The valve operating device for an internal combustion engine according to claim 3, wherein the support pin and the fixing screw member are brought into surface contact with each other.

  During operation of the device, even if a load is applied to the fixing screw member from the support pin, the contact pressure between the two can be made sufficiently small, so that the contact portion between the support pin and the fixing screw member is prevented from becoming sag. Thus, the occurrence of backlash between the two can be suppressed.

  (5) The front end surface of the fixing screw member is formed flat on the outer peripheral surface of the support pin, while the flat portion on which the front end portion of the fixing screw member abuts is formed. 3. A valve operating apparatus for an internal combustion engine according to 3).

  Regardless of the direction in which the fixing screw member is inserted into the fixing hole, it is possible to always bring the tip end surface into surface contact with the flat portion of the support pin.

  (6) The valve operating apparatus for an internal combustion engine according to (5), wherein a mark for recognizing the position of the planar portion is formed on a head on one end side of the support pin.

  When the support pin is inserted into the pin hole of the arm part, the flat part is positioned toward the opening side of the fixing hole by the mark on the head and is aligned with the position orthogonal to the tip part of the fixing screw member. Therefore, the plane portion and the flat front end surface of the fixing screw member can always be brought into surface contact.

  (7) A variable lift mechanism for changing a valve lift amount of the engine valve by changing a rocking position of the rocking cam is provided in a rocking force transmission path of the transmission mechanism. 2. The valve operating apparatus for an internal combustion engine according to 1.

  In this invention, since the minimum valve lift amount of the engine valve can be adjusted by the variable lift mechanism, it is possible to reduce the deviation of the valve lift amount as much as possible, and the valve lift between the cylinders. Variation in quantity can be sufficiently prevented.

  The present invention is not limited to the configuration of the above-described embodiment. For example, the variable mechanism that makes the valve lift variable may have another structure, and the drive cam may have, for example, a raindrop structure. . It is also possible to apply the lift adjusting mechanism to the exhaust valve side or both valve sides in addition to the intake valve side.

It is a disassembled perspective view of the rocker arm and lift adjustment mechanism which are provided to 1st Embodiment of this invention. It is a side view which shows the rocker arm and lift adjustment mechanism which are provided to this embodiment partially in cross section. It is principal part sectional drawing of this embodiment. It is a principal part perspective view of the valve gear in this embodiment. It is a principal part top view of the valve gear in this embodiment. A is an operation explanatory view showing an open state of the intake valve during minimum valve lift control in the present embodiment, and B is an operation explanatory view showing a closed state of the intake valve. A is an operation explanatory view showing an open state of the intake valve during maximum valve lift control in the present embodiment, and B is an operation explanatory view showing a closed state of the intake valve. It is a disassembled perspective view of the rocker arm and lift adjustment mechanism which are provided to 2nd Embodiment. It is a side view of a rocker arm, a lift adjustment mechanism, and a link rod that are used in this embodiment. FIG. 10 is a sectional view taken along line AA in FIG. 9. It is a top view of the rocker arm provided to this embodiment, a lift adjustment mechanism, and a link rod.

Explanation of symbols

2 ... Intake valve (engine valve)
DESCRIPTION OF SYMBOLS 3 ... Drive shaft 4 ... Cam shaft 5 ... Drive cam 7 ... Swing cam 8 ... Transmission mechanism 9 ... Control mechanism 13 ... Rocker arm 13b ... Other end part 15 ... Link rod 15a ... One end part 15c * 15c ... Pin hole 16 ... Lift Adjustment mechanism 17 ... Linking part 18 ... Fixing screw member 18c ... Tip face 19 ... Female screw hole 20 ... Support pin 20c ... Flat part 20e · 20f ... Flat part 18d and 20h ... Tool insertion hole 22 ... Pin insertion hole 23 ... Adjustment shim 23c ... Arc surface 25 ... Control shaft 26 ... Control cam 30 ... Second female screw hole 31 ... Adjustment screw member 31a ... engagement groove

Claims (3)

A drive shaft that is rotationally driven by the crankshaft of the engine, and a drive eccentric cam integrally fixed to the outer periphery;
A swing cam for opening and closing the engine valve;
A transmission mechanism that converts the rotational motion of the drive eccentric cam transmitted through the drive shaft into a swing motion and transmits the swing motion to the swing cam;
A link member that constitutes a part of the transmission mechanism and is swingably provided with a support pin inserted into a pin hole on one end side as a fulcrum;
The support pin is fixed to the predetermined member by a fixing member that is provided on a predetermined member to which the support pin is fixed and is inserted through a fixing hole that opens toward the upper side in the direction of gravity. A lift adjustment mechanism configured to sandwich an adjustment shim between the support pins;
A valve operating apparatus for an internal combustion engine, comprising: A drive shaft that is rotationally driven by the crankshaft of the engine, and a drive eccentric cam integrally fixed to the outer periphery;
A swing cam for opening and closing the engine valve;
A transmission member for converting the rotational motion of the drive eccentric cam transmitted through the drive shaft into a swing motion;
A rocker arm that rocks freely with a rocker shaft as a fulcrum, and a rocking force is transmitted from the transmission member;
An arm portion provided integrally with the rocker arm and swinging in synchronization with the swinging motion of the rocker arm;
A link member for transmitting the swing motion of the arm portion to the swing cam;
A support pin fixed to the arm portion and serving as a swing fulcrum of the link member;
A pin insertion hole provided in each of the arm portions, through which the support pin can be inserted, a fixing hole formed perpendicular to the pin insertion hole, and directed substantially upward in the direction of gravity; and the pin insertion hole, Shim insertion holes formed orthogonal to the fixing holes;
A fixing member that is inserted through the fixing hole and contacts the support pin from an orthogonal direction;
An adjustment shim inserted through the shim insertion hole and sandwiched between the support pin and the inner peripheral surface of the shim insertion hole;
A valve operating apparatus for an internal combustion engine, comprising: A drive shaft that is rotationally driven by the crankshaft of the engine, and a drive eccentric cam integrally fixed to the outer periphery;
A swing cam for opening and closing the engine valve;
A transmission mechanism that converts the rotational motion of the drive eccentric cam transmitted through the drive shaft into a swing motion and transmits the swing motion to the swing cam;
A link member that constitutes a part of the transmission mechanism and is swingably provided with a support pin inserted into a pin hole on one end side as a fulcrum;
An adjustment screw member having an engagement portion that is screwed into an adjustment female screw hole formed in a predetermined member to which the support pin is fixed, and that engages with a tool that applies a rotational force;
The adjusting screw member has a fitting portion which is provided in the predetermined member so as to be screwed into a fixing female screw hole formed on the upper side in the direction of gravity and into which a tool for applying a rotational force is fitted on the upper end side. A fixing screw member capable of sandwiching the support pin between
The tip end portion of the tool, which is continuously formed in the axial direction of the fixing screw member and the radial direction of the support pin, faces the engaging portion of the adjusting screw member, and is inserted from above the fixing screw member. A tool insertion portion that engages the engagement portion of the adjustment screw member;
A valve operating apparatus for an internal combustion engine, comprising:

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