JP5210225B2 - Variable valve gear for engine - Google Patents

Description

  The present invention provides a valve mechanism that has a slide member that slides in a predetermined direction and that can change the operating characteristics of the engine valve in accordance with the operation of the slide member, and that opens and closes the engine valve. Power that is accommodated in a valve operating chamber formed between a cylinder head that slidably supports the cylinder head and a head cover coupled to the cylinder head, and operates the slide member so as to change the operating characteristics of the engine valve. A variable lever of the engine is mounted between the actuator and the slide member, and a rotation lever is provided between the actuator and the slide member to rotate in accordance with the operation of the actuator to slide the slide member. The present invention relates to a valve device.

  A variable valve operating system for an engine that can change the operating characteristics of an engine valve by disabling relative rotation and enabling axial relative movement and moving a valve cam provided on the camshaft in an axial direction by an actuator. As already known from Patent Document 1 and the like, in such a variable valve operating apparatus, the large valve operating cam itself is driven by the actuator, so that the actuator becomes large. Therefore, the present applicant connects a rotating lever that is driven to rotate by an actuator supported by the head cover to a slide member that is connected to a separate cam that is separate from the valve cam. Has already been proposed (Japanese Patent Application No. 2007-256790) in which an actuator is miniaturized by driving the shaft in the axial direction.

Japanese Patent Laid-Open No. 61-212615

  However, in the technique of the above proposal (Japanese Patent Application No. 2007-256790), the longitudinal direction of the rotary lever provided between the slide member supported on the cylinder head side and the actuator attached to the head cover is It is a direction along the coupling direction of the head cover, and the support shaft that pivotally supports the rotation lever is set in a direction perpendicular to the coupling direction, and a gasket made of rubber is interposed between the cylinder head and the head cover. Yes. Therefore, the distance between the actuators on both ends of the rotating lever and the distance between the connecting portions to the slide member is shifted, and the shift causes the lever ratio of the rotating lever to change, resulting in an error in the slide amount of the slide member accompanying the operation of the actuator. there is a possibility.

  The present invention has been made in view of such circumstances, and the engine in which the lever ratio of the rotating lever does not change even if a deviation occurs in the distance between the slide member and the actuator along the coupling direction of the cylinder head and the head cover. An object of the present invention is to provide a variable valve operating apparatus.

  In order to achieve the above object, the present invention has a slide member that slides in a predetermined direction, and can change the operating characteristics of the engine valve in accordance with the operation of the slide member, thereby opening and closing the engine valve. A valve operating mechanism is accommodated in a valve operating chamber formed between a cylinder head that slidably supports the slide member and a head cover coupled to the cylinder head so as to change the operating characteristics of the engine valve. An actuator that exerts power to operate the slide member is attached to the head cover, and a rotation lever that rotates according to the operation of the actuator to slide the slide member between the actuator and the slide member. In the variable valve gear for an engine provided, the cylinder head and the head cover The rotating lever connected to the slide member, which is coupled with a gasket made of an elastic material interposed therebetween and slidable in a direction perpendicular to the coupling direction of the cylinder head and the head cover, is coupled to the coupling direction. A first feature is that the bearing is rotatably supported by a support shaft supported by at least one of the cylinder head and the head cover.

  In addition to the configuration of the first feature, the present invention has a second feature that a knock pin having an axis along the coupling direction is provided between the cylinder head and the head cover.

  In addition to the configuration of the first or second feature, the third feature of the present invention is that both ends of the support shaft are supported by the cylinder head and the head cover.

  In addition to any of the configurations of the first to third features, the present invention provides the engine in a portion excluding the head cover so as to run a cam chain that transmits rotational power to a camshaft included in the valve mechanism. An adjustment chamber having an opening provided in the head cover corresponding to a cam chain traveling passage provided in the main body, communicating with the valve operating chamber through the opening and having a cross-sectional area larger than the cross-sectional area of the opening. An actuator connecting portion formed in the head cover and penetrating into the adjustment chamber through the opening is provided on the rotating lever so as to connect the tip portion to the actuator, and the tip of the actuator connecting portion And an adjustment mechanism for adjusting a rotation amount of the rotation lever according to the operation of the actuator is accommodated in the adjustment chamber. It is provided Te and fourth said.

  In addition to the configuration of the first feature of the present invention, the actuator is attached to the head cover so that the entire actuator is overlapped with the head cover when viewed from the direction along the coupling direction. A fifth feature is that a fastened portion provided on the head cover is fastened to the cylinder head.

  The exhaust valve 25 of the embodiment corresponds to the engine valve of the present invention, the rod 59 of the embodiment corresponds to the slide member of the present invention, and the solenoid 64 of the embodiment corresponds to the actuator of the present invention.

  According to the first feature of the present invention, since an elastic gasket is interposed between the cylinder head and the head cover, it is difficult for heat and vibration on the cylinder head side to be transmitted to the head cover side, and heat is applied to the actuator attached to the head cover. And transmission of vibrations can be suppressed. In addition, the axis of the support shaft that rotatably supports the rotation lever that rotates according to the operation of the actuator attached to the head cover to drive the slide member is set in a direction along the coupling direction of the cylinder head and the head cover. Therefore, even if a gap occurs in the coupling direction between the connecting portion of the rotating lever to the actuator and the slide member by inserting an elastic gasket between the cylinder head and the head cover, the lever ratio is increased. It is possible to avoid the change and prevent an error from occurring in the slide amount of the slide member.

  Further, according to the second feature of the present invention, it is more reliable that the lever ratio of the rotating lever is changed so that the knock pin does not shift in a direction perpendicular to the coupling direction of the cylinder head and the head cover. Can be prevented.

  According to the third feature of the present invention, the both ends of the support shaft are supported by the cylinder head and the head cover, and the axis of the support shaft is set with a simple configuration in the direction along the coupling direction of the cylinder head and the head cover. be able to.

  According to the fourth aspect of the present invention, the adjustment chamber in which the connecting portion of the actuator and the rotation lever is arranged by reducing the cross-sectional area of the opening provided in the head cover by connecting the valve operating chamber and the adjustment chamber. It is difficult for hot oil to enter the side, preventing the actuator from becoming hot, and even if blow-by gas enters the control chamber due to pressure fluctuations on the cam chain passage side, the pressure is controlled in the control chamber. The oil can be returned to the cam chain passage while relaxing, and the actuator can be linked to and connected to the rotating lever while avoiding adverse effects from the valve train chamber side as much as possible. The operating amount of the corresponding slide member can be adjusted.

  Further, according to the fifth feature of the present invention, the actuator is arranged so that the entire actuator is overlapped with the head cover when viewed from the direction along the coupling direction of the cylinder head and the head cover, so that the external force acts on the solenoid. The actuator can be protected by preventing the head cover as much as possible, and the fastening portion provided in the vicinity of the actuator and provided on the head cover is fastened to the cylinder head, so that the support rigidity of the actuator to the head cover is increased. Can do.

1 is a side view of a motorcycle. It is a principal part longitudinal cross-sectional view of the engine seen from the same direction as FIG. FIG. 3 is a sectional view taken along line 3-3 in FIG. 2. FIG. 4 is an enlarged view of a portion indicated by arrow 4 in FIG. 3. It is a figure which shows the valve opening lift characteristic of an intake valve and an exhaust valve. FIG. 6 is a sectional view taken along line 6-6 of FIG. FIG. 7 is a view taken in the direction of arrow 7 in FIG. 2. FIG. 8 is a cross-sectional view taken along line 8-8 in FIG. 7. FIG. 9 is a cross-sectional view taken along line 9-9 in FIG. 7. FIG. 10 is an enlarged cross-sectional view taken along line 10-10 of FIG. 4 in a decompressed state. It is a disassembled perspective view of a decompression means. FIG. 11 is a cross-sectional view corresponding to FIG. 10 in a decompressed state.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

  A first embodiment of the present invention will be described with reference to FIGS. 1 to 12. First, in FIG. 1, an engine E and a fuel tank T are mounted on a body frame F of the motorcycle, and its front end is shown. The front wheel Wf is supported through the front fork 1 to which the steering handle 2 is connected to the upper part, and the swing arm SA that supports the rear wheel Wr is swingable up and down at a substantially central portion of the vehicle body frame F. A rear cushion R is provided between the swing arm SA and the vehicle body frame F. The driving force of the engine E is transmitted to the rear wheel Wr via the chain transmission mechanism 4.

  The vehicle body frame F includes a head pipe H that supports the front fork 1 so as to be steerable, a down tube DT that extends downward from the head pipe H and passes through the front of the engine E, and a rear lower part of the head pipe H. A main frame MF that extends and extends downward through the upper and rear sides of the engine E, a seat tube St that is fixed at the front end of the main frame MF and extends rearward, and an intermediate portion of the seat tube ST and the main frame MF The back tube BT which connects between rear parts is provided. An engine E is supported between a rear portion of the main frame MF and a lower portion of the down tube DT, and a tandem seat S is supported on the seat tube ST.

  2 and 3, the engine body 10 of the engine E is configured by coupling a crankcase 11, a cylinder block 12, a cylinder head 13 and a head cover 14, and the cylinder block 12 can freely slide a piston 15. A cylinder head 13 having a cylinder bore 16 fitted to the cylinder block 11 and coupled to the crankcase 11 and forming a combustion chamber 17 facing the top of the piston 15 with the cylinder block 12 is coupled to the cylinder block 12. A head cover 14 is coupled to the cylinder head 13 from the side opposite to the cylinder block 12. Moreover, a gasket 9 made of an elastic material is interposed between the cylinder head 13 and the head cover 14.

  The cylinder head 13 is provided with an intake port 18 opened on one side surface thereof and an exhaust port 19 opened on the other side surface of the cylinder head 13, and an intake pipe 21 forming an intake passage 20 communicating with the intake port 18. Is connected to the cylinder head 13, and a fuel injection valve 22 is attached to the intake pipe 21.

  The cylinder head 13 has an intake valve 24 for switching communication / blocking between the intake port 18 and the combustion chamber 17 and an exhaust valve 25 for switching communication / blocking between the exhaust port 19 and the combustion chamber 17. The intake valve 24 and the exhaust valve 25 are urged in the valve closing direction by the valve springs 26 and 27. Further, a spark plug 23 is attached to the cylinder head 13 so that the tip of the cylinder head 13 faces the combustion chamber 17.

  Referring also to FIG. 4, the intake valve 24 and the exhaust valve 25 are driven to open and close by a valve mechanism 29 housed in a valve chamber 28 formed between the cylinder head 13 and the head cover 14. The valve mechanism 29 is arranged between the intake valve 24 and the exhaust valve 25 and the camshaft 32 provided with the intake cam 30 and the exhaust cam 31 is different from the exhaust cam 31 in the cam profile. In addition, a slide cam 33 is mounted on the outer periphery of the camshaft 32 so as to be movable in the axial direction and is not relatively rotatable, and a decompressor is mounted on the camshaft 32 so as to sandwich the exhaust cam 31 between the slide cam 33. Means 34 and an intake side and exhaust side lock supported by the cylinder head 14 having an axis parallel to the camshaft 32. Shafts 36 and 37, an intake side rocker arm 38 swingably supported on the intake side rocker shaft 36 so as to open and close the intake valve 24 following the intake cam 30, the exhaust cam 31, and the slide An exhaust-side rocker arm 39 swingably supported by an exhaust-side rocker shaft 37 so as to open and close the exhaust valve 25 by being driven by a cam 33 or a decompression cam 35 of the decompression means 34, and a direction into the camshaft 32 And a rod 59 which is a slide member inserted so as to be movable, and is supported by the cylinder head 13.

  The cylinder head 13 is integrally provided with a first support portion 42 having a first bearing hole 40 and a second support portion 43 having a second bearing hole 41 coaxial with the first bearing hole 40. The camshaft 32 is rotatably supported by the cylinder head 13 via first and second ball bearings 44 and 45 which are a pair of bearings arranged at intervals in the axial direction of the camshaft 32. One end of the camshaft 32 is rotatably supported by the first support portion 42 with a first ball bearing 44 interposed between the inner periphery of the first bearing hole 40, and close to the other end of the camshaft 32. This portion passes through the second bearing hole 41 in a freely rotatable manner, and a second ball bearing 45 is interposed between the inner periphery of the second bearing hole 41 and the camshaft 32. Thus, the camshaft 32 is press-fitted into the inner rings of the first and second ball bearings 44 and 45, and the intake cam 30 and the exhaust cam 31 dispose the intake cam 30 on the first ball bearing 44 side and exhaust the cam. The cam 31 is formed integrally with the cam shaft 32 between the first and second ball bearings 44 and 45 so as to be disposed on the second ball bearing 45 side, and the decompression means 34 is connected to the intake cam 30 and the exhaust cam. The slide cam 33 is mounted on the camshaft 32 at a position sandwiching the exhaust cam 31 with the decompression cam 35 of the decompression means 34.

  Rotational power from a crankshaft (not shown) is transmitted to the camshaft 32 via a timing transmission mechanism 47. The timing transmission mechanism 47 is transmitted from the second ball bearing 45 of the camshaft 32. An endless cam chain 50 is wound around a driven sprocket 48 fixed to the projecting end of the cylinder and a drive sprocket (not shown) fixed to the crankshaft. It is stored in a chain travel passage 51 formed over the block 12, the cylinder head 13 and the head cover 14 so as to travel.

  Referring to FIG. 2, the intake cam 30 and the exhaust cam 31 have arc-shaped base circle portions 30a and 31a centering on the axis of the camshaft 32 and outward of the base circle portions 30a and 31a. The upper circular portions 30b and 31b are connected to each other in the circumferential direction so as to protrude, and are formed integrally with the camshaft 32 by shifting the phases of the high positional portions 30b and 31b.

  A roller 52 that is in rolling contact with the intake cam 30 is pivotally supported at one end portion of the intake side rocker arm 38 that is swingably supported by the intake side rocker shaft 36, and an intake valve is provided at the other end portion of the intake side rocker arm 36. A tappet screw 53 abutting on the stem end 24a of 24 is screwed together so that the advance / retreat position can be adjusted.

  At one end of the exhaust-side rocker arm 39 that is swingably used by the exhaust-side rocker shaft 37, a roller 56 that can be brought into rolling contact with the exhaust cam 31 and the slide cam 33 is pivotally supported. A tappet screw 54 that abuts on the stem end 25a of the exhaust valve 25 is screwed to the other end so that the advance / retreat position can be adjusted.

  Further, a contact portion 39a adjacent to the roller 56 is provided at one end portion of the exhaust side rocker arm 39 so as to contact the decompression cam 35 of the decompression means 34, and at least the camshaft 32 side of the contact portion 39a is provided. This end is formed to be the same as the outer periphery of the roller 56 as viewed from the direction along the axis of the camshaft 32 or to protrude toward the camshaft 32 from the outer periphery.

  The slide cam 33 is located close to the exhaust cam 31 and is in contact with the roller 56 of the exhaust side rocker arm 39 (the position indicated by the solid line in FIGS. The camshaft 32 can be moved in the axial direction of the camshaft 32 between a non-operating position (a position indicated by a chain line in FIG. 4) that avoids contact of the side rocker arm 39 with the roller 56. The camshaft 32 is fitted and supported on the outer periphery of the camshaft 32 such that relative rotation around the axis is impossible.

  In FIG. 5, the slide cam 33 is an exhaust gas recirculation cam that opens the exhaust valve 25 so that a part of the exhaust gas discharged from the combustion chamber 17 is returned to the combustion chamber 17. The base circle portion 33a of the slide cam 33 has a base circle portion 33a of the exhaust cam 31. It is formed with a smaller diameter than 31a.

  Moreover, the high-order part 33b protrudes slightly from the said base circle part 33a in the phase corresponding to the valve closing end of the high-order part 30b in the intake cam 30, and the circumferential direction both ends of the high order part 33b draw a smooth curve. In this way, it is continuous with the base circle 33a. Thus, when the slide cam 33 is moved to the operating position where it abuts against the roller 56 of the exhaust side rocker arm 39, the exhaust side rocker arm 39 is rotated so that the exhaust valve 25 is opened by the high portion 31b of the exhaust cam 31. After that, the valve closed state is maintained by contacting the base circle portion 31a of the exhaust cam 31, but at the end of the intake valve 24 being closed, the exhaust valve 25 is moved by the high portion 33b of the slide cam 33. The exhaust side rocker arm 39 is slightly rotated so that the valve is slightly opened. As a result, the exhaust valve 25 can be temporarily opened during the compression stroke, and the combustion of the air-fuel mixture in the combustion chamber 17 is activated by the exhaust gas, thereby reducing NOx emissions, improving engine output, and reducing fuel consumption. Etc. can be achieved.

  On the other hand, when the slide cam 33 moves to a non-operating position that avoids contact with the roller 56 of the exhaust side rocker arm 39, the exhaust side rocker arm 39 is driven to rotate only by the exhaust cam 31, and the exhaust valve 25 is connected to the exhaust cam 31. The opening / closing operation is performed in an operation mode corresponding to the cam profile. That is, the opening / closing operation mode of the exhaust valve 25 corresponding to the cam profile of the exhaust cam 31 and the opening / closing operation corresponding to the cam profile of the exhaust cam 31 are obtained while the valve is originally closed. The operation mode of the exhaust valve 25 can be switched by the movement of the slide cam 33 along the axial direction of the camshaft 32.

  The camshaft 32 has a coaxial center hole 57 and is formed hollow, and the driven sprocket 48 is provided with a center hole 48 a corresponding to the center hole 57. The camshaft 32 is coaxially screwed with a bolt 58 that closes the end of the center hole 57 on the opposite side of the driven sprocket 48. A rod 59 having a small diameter shaft portion 59a facing the bolt 58 is coaxially inserted into the center hole 57 so as to be axially movable, and the other end of the rod 59 is connected to the driven sprocket 48. Protruding from.

  A guide hole 60 that connects the inner peripheral surface of the center hole 57 and the outer peripheral surface of the cam shaft 32 to the cam shaft 32 at a portion where the slide cam 33 is disposed and extends in the axial direction of the cam shaft 32. Is provided. Thus, in the first embodiment, as shown in FIG. 6, a pair of guide holes 60, 60 having an axis perpendicular to the axis C of the center hole 57 is provided in the camshaft 32. The slide cam 33 and the rod 59 which are mounted on the outer periphery so as to be movable in the axial direction slide through the guide holes 60 in the direction along the axis C while passing through the guide holes 60. The connection pins 61 are connected.

  As a result, the slide cam 33 is in the position of contact with the roller 56 in the cam contact portion 55 of the exhaust rocker arm 39 in the vicinity of the exhaust cam 31 while disabling relative rotation around the axis of the cam shaft 32. It is possible to move in the axial direction of the camshaft 32 between the camshaft portion 55 of the exhaust side rocker arm 39 that is separated from the exhaust cam 31 and avoids contact with the roller 56, The camshaft 32 is fitted and supported on the outer periphery.

  Between the rod 59 and the bolt 58, a coiled return spring 62 surrounding the small-diameter shaft portion 59a of the rod 59 is contracted, and the rod 59 is on the side where the slide cam 33 is in the non-operating position. Is biased by the return spring 62.

  Referring also to FIG. 7, the rod 59 is driven by a rod so as to move the slide cam 33 between the non-operating position and the operating position in order to change the operating characteristics of the exhaust valve 25 in the valve operating mechanism 29. The rod driving means 63 is attached to the engine main body 10 so as to exert power for operating the valve mechanism 29 so as to change the operating characteristics of the exhaust valve 25. A solenoid 64 that is an actuator to be operated, and a rotation lever 67 that transmits an output of the solenoid 64 to the rod 59 of the valve operating mechanism 29.

  As shown in FIG. 8, the crankcase 11, the cylinder block 12, and the cylinder head 13 are fastened by a plurality of, for example, four through bolts 68, 68... Screwed to the crankcase 11, and the head cover 14 is a cylinder. A gasket 9 made of an elastic material is interposed between the head 13 and a plurality of bolts 90, 90, for example, two bolts 90, 90 as shown in FIG. In between, elastic members 89 are interposed. Further, between the cylinder head 13 and the head cover 14, a direction parallel to the coupling surface of the cylinder head 13 and the head cover 14, that is, a coupling direction 69 when the cylinder head 13 and the head cover 14 are coupled to each other with bolts 90. A knock pin 70 having an axis along the line is provided.

  Incidentally, the axis of the camshaft 32 and the axis of the rod 59 slidably inserted into the camshaft 32 extend in a direction perpendicular to the coupling direction 69, and are connected to the rod 59. The rotation lever 67 has an axis along the coupling direction 69 and is rotatably supported by a support shaft 66 supported by at least one of the cylinder head 13 and the head cover 14 in the first embodiment. .

  Referring also to FIG. 8, the cylinder head 13 is integrally provided with a shaft support portion 92 having a bottomed press-fitting hole 91 into which one end portion of the support shaft 66 is press-fitted. A shaft support portion 94 having a support hole 93 for fitting and supporting the other end portion of the support shaft 66 is provided corresponding to the shaft support portion 92 on the cylinder head 13 side.

  The rotating lever 67 has a pair of substrate portions 67a, 67b that slide through the support shaft 66 and slidably contact the shaft support portions 92, 94 of the cylinder head 13 and the head cover 14, respectively, and the substrate portions 67a, 67b. A connecting plate portion 67c that connects the connecting plate portion 67c, an arm portion 67d that extends from a portion of the connecting plate portion 67c closer to the cylinder head 13 toward the rod 59 side and abuts against the rod 59, and the connecting plate An actuator connecting arm portion 67e extending from the portion of the portion 67c near the head cover 14 to the opposite side of the cylinder head 13 is integrally provided.

  Incidentally, an opening 95 is provided in the head cover 14 corresponding to the cam chain passage 51 provided in the engine body 10 excluding the head cover 14, and the actuator connecting portion 67 e of the rotating lever 67 is provided in the opening 95. And protrudes outward from the valve operating chamber 28.

  On the other hand, a protruding portion 14a protruding outward is integrally formed on the outer surface of the head cover 14 at a portion corresponding to the opening 95, and the opening 95 is provided in the middle portion of the protruding portion 14a. A circular hole 96 is formed so as to have an axis perpendicular to a plane parallel to the axes of the support shaft 66, the camshaft 32, and the rod 59.

  A lid member 97 that airtightly closes one end of the circular hole 96 is screwed to the protrusion 14a, and a mounting plate 98 of the solenoid 64 closes the other end of the circular hole 96 in an airtight manner. Fastened by a pair of bolts 99, 99. Thus, as shown in FIG. 7, the solenoid 64 is configured so that the entire solenoid 64 overlaps the head cover 14 when viewed from the direction along the coupling direction 69 of the cylinder head 13 and the head cover 14, that is, the head cover 14. The solenoid 64 is attached to the protrusion 14a of the head cover 14 so that the solenoid 64 does not protrude outward. In addition, the head cover 14 is integrally provided with a fastened portion 14a projecting sideways in the vicinity of the protrusion 14a. The fastened portion 14a is fastened to the cylinder head 13 by a bolt 100, and the bolt 100 Further, an elastic member (not shown) similar to the elastic member 89 interposed between the bolts 90 and the head cover 14 is interposed between the fastened portions 14a. That is, the head cover 14 is fastened to the cylinder head 13 by the two bolts 90... And the bolt 100 inserted through the fastened portion 14 b disposed in the vicinity of the solenoid 64.

  The protrusion 14 a of the head cover 14 and the lid member 97 and the mounting plate 98 fixed to the protrusion 14 a so as to close both ends of the circular hole 66 provided in the protrusion 14 a are arranged via the opening 95. Thus, the adjustment chamber 101 communicating with the valve operating chamber 28 is formed, and the cross-sectional area of the adjustment chamber 101 is set larger than the cross-sectional area of the opening 95.

  The solenoid 64 has an output shaft 65 that has an axis that is orthogonal to the axis of the rod 59 and that is parallel to a plane that passes through the axis of the support shaft 66 and is movable in the axial direction. The adjustment lever 101 is inserted into the adjustment chamber 101, and the tip of the actuator connecting portion 67 e of the rotation lever 67 is connected to the output shaft 65 in the adjustment chamber 101.

  In addition, an adjustment mechanism 102 that adjusts the amount of rotation of the rotation lever 67 that accompanies the operation of the solenoid 64 is provided at the distal end of the actuator connecting portion 67 e so as to be accommodated in the adjustment chamber 101.

  The adjustment mechanism 102 includes a weld nut 103 that is fixed to the tip of the actuator connecting portion 67e, a tappet screw 104 that is screwed into the weld nut 103 and passes through the actuator connecting portion 67e, and a screw that is screwed into the tappet screw 104. The stopper nut 105 is in contact with and engaged with the weld nut 103, and the tappet screw 104 contacts the tip of the output shaft 65. Thus, by loosening the locking nut 105, the axial advance / retreat position of the tappet screw 104 can be adjusted, whereby the rotation amount of the rotation lever 67 in accordance with the operation of the solenoid 64, that is, the movement amount of the rod 59. Will be adjusted.

  Referring to FIGS. 10 to 12 together, the decompression means 34 is used in a state where the engine speed, that is, the rotational speed of the camshaft 32 is relatively low in order to reduce the exhaust pressure at the time of starting the engine and facilitate the starting. The decompression means 34 is slightly opened at the timing when the exhaust valve 25 is originally closed, and this decompression means 34 is rotatably supported by the intake cam 30 and the exhaust cam 31 via a decompression pin 71 having an axis parallel to the camshaft 32. 10 and the camshaft 32 that protrudes from the base circle portion 31a of the exhaust cam 31 and contacts the contact portion 39a of the exhaust rocker arm 39 when the engine speed is low. When the decompression weight 72 is rotated by the action of the centrifugal force generated as it rotates, the exhaust side To so as not to abut against the abutting portion 39a of Kaamu 39 and a decompression cam 35 that is coupled to the decompression weight 72 is disposed between the intake cam 30 and an exhaust cam 31.

  The decompression weight 72 is formed in an arc shape so as to cover a substantially half circumference of the camshaft 32 from the side, and a portion of one surface thereof is in sliding contact with the intake cam 30 of the camshaft 32 and the exhaust cam 30 and the exhaust gas. The decompression weight 72 is disposed between the cams 31, and one end of the decompression weight 72 is disposed to correspond to the high position portion 31 b of the exhaust cam 31 of the camshaft 32. In addition, a surface of the one end portion of the decompression weight 72 that faces the exhaust cam 31 is provided with a circular accommodating recess 74 that opens to the exhaust cam 31 side. The accommodating recess 74 has one end portion of a cylindrical support boss 75. Are fitted. Also, a flange 75a that projects radially outward is integrally provided at the other end of the support boss 75 so as to be flush with the other end surface of the support boss 75, and the other end of the support boss 75 is the camshaft 32. The exhaust cam 31 is in contact with the high position portion 31b.

  The decompression pin 71 is inserted into the intake cam 30, the decompression weight 72, the support boss 75, and the exhaust cam 31 from the intake cam 30 side, and the decompression pin 71 is inserted into the intake cam 30. A through hole 76 is provided, and a second through hole 77 through which the decompression pin 71 is inserted is provided at one end portion of the den compression pin 71 so as to be coaxially connected to the housing recess 74, and the high position portion 31 b in the exhaust cam 31. A bottomed insertion hole 78 through which the decompression pin 71 is inserted is provided coaxially with the first and second through holes 76 and 77 and opened to the intake cam 30 side.

  Thus, the decompression pin 71 is inserted from the intake cam 30 side into the first through hole 76 of the intake cam 30, the second through hole 77 of the decompression weight 72, the support boss 75, and the insertion hole 78 of the exhaust cam 31. One end portion of the decompression weight 72 is rotatably supported by the intake cam 30 and the exhaust cam 31 via a decompression pin 71 supported at both ends by the intake cam 30 and the exhaust cam 31.

  In addition, the outer periphery of the washer 79 (see FIGS. 3 and 4) is in contact with the other end of the decompression pin 71 whose one end is in contact with the closed end of the insertion hole 78, whereby the first penetration of the decompression pin 71 is achieved. Separation from the hole 76, the second through hole 77, the support boss 75, and the insertion hole 78 is prevented. That is, the outer peripheral portion of the washer 79 having the inner peripheral portion sandwiched between the inner ring of the first ball bearing 44 and the camshaft 32 is held by the intake cam 30 in order to keep the distance between the first ball bearing 44 and the intake cam 30 constant. However, the outer periphery of the washer 79 is brought into contact with the other end of the decompression pin 71, and a dedicated part for determining the axial position of the decompression pin 71 can be dispensed with.

  One end of a coiled torsion spring 80 surrounding the support boss 75 is engaged with a bottomed engagement hole 81 provided in the camshaft 32, and the other end of the torsion spring 80 is connected to the decompression spring. The weight 72 is engaged with an engagement hole 82 provided at one end. Due to the spring force of the torsion spring 80, the decompression weight 72 is biased toward the side where the intermediate portion of the decompression weight 72 is brought close to the outer peripheral surface of the camshaft 32.

  The decompression cam 35 is disposed between the other end side of the decompression weight 72 and the exhaust cam 31 at a position corresponding to the base circle portion 31 a of the exhaust cam 31, and the decompression cam implanted in the exhaust cam 31. The shaft 84 is rotatably supported. Thus, the decompression cam shaft 84 has an axis parallel to the axis of the camshaft 32, and the decompression cam 35 is supported by the camshaft 32 so as to be able to rotate around an axis parallel to the axis of the camshaft 32. The

  The decompression cam 35 is basically formed in a cylindrical shape coaxial with the decompression cam shaft 84, but a part of the decompression cam 35 on the exhaust cam 31 side is a flat portion 85 parallel to the axis of the decompression cam 35. Is cut out to form. That is, the outer periphery of the decompression cam 35 on the exhaust cam 31 side is formed by an arc portion 86 centering on the axis line of the decompression cam shaft 84 and the flat portion 85 connecting both ends in the circumferential direction of the arc portion 86. As shown in FIG. 12, the decompression cam 35 is in a decompression-off state in which the flat surface portion 85 located on the inner side of the base circle portion 31a of the exhaust cam 31 faces outward, as shown in FIG. The arc portion 86 can be rotated between a decompression state in which a part of the arc portion 86 protrudes outward from the base circle portion 31 a of the exhaust cam 31.

  Thus, when the arc portion 86 of the decompression cam 35 protrudes outward from the base circle portion 31a, the contact portion 39b of the exhaust side rocker arm 39 contacts the arc portion 86, so that the exhaust side rocker arm 39 causes the exhaust valve 25 to move. It will turn to slightly open the valve.

  A connecting pin 87 having an axis parallel to the camshaft 32 is press-fitted into the other end portion of the decompression weight 72, and a guide groove 88 for fitting a protruding portion of the connecting pin 87 from the decompression weight 72 is formed in the decompression cam. The decompression cam 35 is provided at a portion on the decompression weight 72 side so as to extend along the radial direction of the decompression cam 35. Thus, since the rotational speed of the camshaft 32 is relatively large, the centrifugal force acting on the decompression weight 72 is large, and the decompression weight 72 cams the intermediate portion of the decompression weight 72 against the biasing force of the torsion spring 80. In the decompression-off state rotated so as to be separated from the outer periphery of the shaft 32, as shown in FIG. 10, the connecting pin 87 fitted in the guide groove 88 rotates together with the decompression weight 72, and in this state, the decompression cam 35 The flat portion 85 is in a rotational position where the flat portion 85 faces outward from the base circle portion 31a of the exhaust cam 31, and the contact portion 39b of the exhaust side rocker arm 39 does not contact the decompression cam 35. The side rocker arm 39 swings according to the cam profile of the exhaust cam 31, and the exhaust valve 25 also follows the cam profile of the exhaust cam 31. Opening and closing operating in the timing. Further, since the rotational speed of the camshaft 32 is relatively small, the centrifugal force acting on the decompression weight 72 is small, and the decompression weight 72 causes the intermediate portion of the decompression weight 72 to move to the outer periphery of the camshaft 32 by the biasing force of the torsion spring 80. In the decompression state rotated so as to be close to each other, as shown in FIG. 12, the connecting pin 87 fitted in the guide groove 88 is rotated together with the decompression cam 56, and in this state, the decompression cam 35 is a part of the arc portion 86. Is in a pivoting position in which it protrudes outward from the base circle portion 31a of the exhaust cam 31, and the contact portion 39b of the exhaust side rocker arm 39 contacts the arc portion 86 of the decompression cam 35. The decompression cam 35 causes the roller 54 to come into contact with the base circle 31a of the cam 31. Swings or not, the exhaust valve 25 even though the cam profile of the exhaust cam 31, so that the slightly opened with a closing timing.

  Moreover, the timing at which the exhaust valve 25 opens at decompression is set to a phase slightly shifted from that timing in the vicinity of the timing at which the exhaust valve 25 is opened by the slide cam 33, as shown in FIG.

  Next, the operation of the first embodiment will be described. The valve mechanism 29 includes a rod 59 that is supported so as to be axially slidable within a camshaft 32 rotatably supported by the cylinder head 13. The operation characteristics of the exhaust valve 25 can be changed by the slide operation of 59, and the solenoid 64 is accommodated in the valve operating chamber 28 formed between the cylinder head 13 and the head cover 14 and exhibits the power to operate the rod 59. Is attached to the head cover 14, and a rotation lever 67 is provided between the solenoid 64 and the rod 59 to rotate in response to the operation of the solenoid 64 to slide the rod 59. 13 and the head cover 14 are joined with a gasket 9 made of an elastic material interposed therebetween. Runode, heat and vibration of the cylinder head 13 side is easily transmitted to the head cover 14 side, it is possible to suppress the heat or vibration is transmitted to the solenoid 64 attached to the head cover 14.

  In addition, the axis of the rod 59 extends in a direction perpendicular to the coupling direction 69 of the cylinder head 13 and the head cover 14, and the rotating lever 67 connected to the rod 59 has an axis along the coupling direction 69. Thus, since it is rotatably supported by a support shaft 66 supported by at least one of the cylinder head 13 and the head cover 14, an elastic gasket 9 is interposed between the cylinder head 13 and the head cover 14. Even if the distance in the coupling direction 69 between the solenoid 64 of the rotating lever 69 and the connecting portion of the rod 59 is shifted, the lever ratio is prevented from changing, and the slide amount of the rod 59 is errored. Can be prevented. In other words, the lever ratio of the rotating lever 67 is such that the length L1 (see FIG. 3) in the direction orthogonal to the connecting direction between the connecting portion of the solenoid 64 to the rotating lever 67 and the axis of the support shaft 66, and the rod 59 is a ratio of a length L2 (see FIG. 9) in a direction orthogonal to the coupling direction between the connecting portion to the rotation lever 67 and the axis of the support shaft 66, and the lengths L1 and L2 are the couplings. Even if the distance between the solenoid 64 and the rod 59 in the direction 69 changes, it does not change.

  Since a knock pin 70 having an axis along the coupling direction 69 is provided between the cylinder head 13 and the head cover 14, the knock pin 70 does not cause a shift in a direction perpendicular to the coupling direction 69 of the cylinder head 13 and the head cover 14. Thus, it is possible to more reliably prevent the lever ratio of the rotation lever 67 from changing.

In addition, since both ends of the support shaft 66 that supports the rotating lever 67 are supported by the cylinder head 13 and the head cover 14, the axis of the support shaft 66 can be easily adjusted in a direction along the connecting direction 69 of the cylinder head 13 and the head cover 14. Can be set in the configuration.
This is the third feature.

  Further, the head cover 14 is provided with an opening 95 corresponding to the cam chain traveling passage 51, communicates with the valve operating chamber 28 through the opening 95 and has a cross-sectional area larger than the cross-sectional area of the opening 95. 101 is formed on the head cover 14, and an actuator connecting portion 67 e that penetrates into the adjustment chamber 101 through the opening 95 is provided on the rotating lever 67 so that its tip end portion is connected to the output shaft 65 of the solenoid 64. In addition, an adjustment mechanism 102 that adjusts the amount of rotation of the rotation lever 67 that accompanies the operation of the solenoid 64 is provided at the tip of the actuator connection portion 67e so as to be accommodated in the adjustment chamber 101. By reducing the cross-sectional area, it is difficult for hot oil to enter the adjustment chamber 101 side where the connecting portion of the solenoid 64 and the rotation lever 67 is disposed. Thus, the solenoid 64 can be prevented from reaching a high temperature, and even if blow-by gas enters the control chamber 101 due to pressure fluctuation on the cam chain passage 51 side, Can be returned to the cam chain passage 51 side, and the solenoid 64 can be linked and connected to the rotation lever 67 while avoiding adverse effects from the valve operating chamber 28 side as much as possible. The operation amount of the rod 59 according to the operation can be adjusted.

  Further, since the solenoid 64 is attached to the head cover 14 so that the entire solenoid 64 is overlapped with the head cover 14 when viewed from the direction along the coupling direction 69, the head cover 14 can prevent external force from acting on the solenoid 64 as much as possible. The solenoid 64 can be protected in such a way as to prevent it.

  Further, since the fastened portion 14b provided on the head cover 14 is fastened to the cylinder head 13 in the vicinity of the solenoid 64, the support rigidity of the solenoid 64 to the head cover 14 can be increased.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various design changes can be made without departing from the present invention described in the claims. Is possible.

DESCRIPTION OF SYMBOLS 9 ... Gasket 10 ... Engine main body 13 ... Cylinder head 14 ... Head cover 14b ... Fastened part 25 ... Exhaust valve 28 which is an engine valve ... Valve operating chamber 29 ... Valve mechanism 32 ... Cam shaft 50 ... Cam chain 51 ... Cam chain travel passage 59 ... Rod 64 as a slide member ... Solenoid 66 as an actuator ... Support shaft 67 ... Rotating lever 67e ... Actuator connecting portion 69 ... Coupling direction 70 ... Knock pin 95 ... Opening 101 ... Adjusting chamber 102 ... Adjusting mechanism E ... Engine

Claims (5)

  It has a slide member (59) that slides in a predetermined direction, and the operating characteristic of the engine valve (25) can be changed according to the operation of the slide member (59), and the engine valve (25) is driven to open and close. A valve operating mechanism (29) is formed between a cylinder head (13) that slidably supports the slide member (59) and a head cover (14) coupled to the cylinder head (13). An actuator (64) housed in the chamber (28) and exhibiting power for operating the slide member (59) so as to change the operating characteristics of the engine valve (25) is attached to the head cover (14), Between the actuator (64) and the slide member (59), the slide member (59) is rotated by rotating according to the operation of the actuator (64). In the variable valve operating system of the engine in which a turning lever (67) for driving the actuator is interposed, the cylinder head (13) and the head cover (14) have a gasket (9) made of an elastic material interposed therebetween. And the rotation lever (67) connected to the slide member (59) slidable in a direction perpendicular to the coupling direction (69) of the cylinder head (13) and the head cover (14). An engine having an axis along a coupling direction (69) and rotatably supported by a support shaft (66) supported by at least one of the cylinder head (13) and the head cover (14). Variable valve gear.   The variable motion apparatus for an engine according to claim 1, wherein a knock pin (70) having an axis along the coupling direction (69) is provided between the cylinder head (13) and the head cover (14).   The variable valve operating apparatus for an engine according to claim 1 or 2, wherein both ends of the support shaft (66) are supported by the cylinder head (13) and the head cover (14).   A cam provided on the engine body (10) except for the head cover (14) so that a cam chain (50) that transmits rotational power is caused to travel to a camshaft (32) included in the valve mechanism (29). An opening (95) is provided in the head cover (14) corresponding to the chain travel passage (51), and the opening (95) communicates with the valve operating chamber (28) through the opening (95). An adjustment chamber (101) having a cross-sectional area larger than the cross-sectional area of the actuator is formed in the head cover (14) and penetrates the opening (95) into the adjustment chamber (101). 67e) is provided on the rotating lever (67) so as to connect the tip thereof to the actuator (64), and the tip of the actuator connecting portion (67c). Further, an adjustment mechanism (102) for adjusting the amount of rotation of the rotation lever (67) accompanying the operation of the actuator (64) is provided so as to be accommodated in the adjustment chamber (101). The variable valve operating apparatus for an engine according to any one of claims 1 to 3.   The actuator (64) is attached to the head cover (14) so that the entire actuator (64) overlaps the head cover (14) when viewed from the direction along the coupling direction (69), and the actuator (64) 2. The variable valve operating apparatus for an engine according to claim 1, wherein a fastened portion (14 b) provided on the head cover (14) is fastened to the cylinder head (13) in the vicinity of the head cover (14).

Images