JP5312152B2 - Variable valve gear for engine - Google Patents

Abstract

The invention provides a variable valve device of an engine. In the variable valve device, the actuating mechanism generates power to drive the variable valve mechanism to act through changing the motion characteristic of the engine valve. The actuating mechanism is installed on the engine main body. Thereby, it is unnecessary to configure a specific part for the actuating mechanism so as to reduce the number of parts. A variable valve mechanism (29A) is borne on a specific engine main body component part (13) on one of two engine main body component parts (13, 14) between which variable valve chambers are formed (28); furthermore, a projecting portion (13c) projecting outwards is integrally formed; the actuating mechanism (64) is borne on an actuating mechanism bearing portion (91) whichis coplanarly connected to a combined face (90) of the engine main body component part (13) and other engine main body component part (12) and formed on the projecting portion (13c); and a rotary rod(67) transmitting output of the actuating mechanism to the variable valve mechanism (29A) can be rotatably borne on the specific engine main body component part (13).

Description

  According to the present invention, the valve operating chamber formed in the engine body has a camshaft and a valve operating mechanism for driving the engine valve so that its operating characteristics can be changed, so as to change the operating characteristics of the engine valve. The present invention also relates to a variable valve operating apparatus for an engine in which an actuator that exerts power for operating the valve operating mechanism is attached to the engine body.

  A separate storage box is attached to a cylinder head or head cover, which is one of a plurality of engine main body constituting members that are coupled to each other, and the actuator and the output of the actuator are supplied to the storage box on the valve mechanism side. A variable valve device for an engine in which a transmission mechanism for transmitting to the engine is supported is known from Patent Document 1.

Japanese Patent No. 4188259

  However, the variable valve operating device disclosed in Patent Document 1 requires a storage box that is separate from the engine body, which increases the number of parts and allows the movement accommodated in the valve chamber in the engine body. There is a possibility that the displacement of the connecting portion of the valve mechanism and the actuator becomes large if strict dimensional control is not performed.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a variable valve operating apparatus for an engine that can reduce the number of parts without using a dedicated member for arranging an actuator.

In order to achieve the above object, according to the present invention, the valve operating chamber formed in the engine body has a camshaft and a valve operating mechanism for driving the engine valve so that its operating characteristics can be changed. In an engine variable valve operating apparatus in which an actuator that exerts power for operating the valve operating mechanism so as to change the operating characteristic of the valve is attached to the engine main body, the hollow camshaft has an axial direction from one side in the axial direction. The valve operating mechanism that changes the operating characteristics of the engine valve by the movement of a rod that is movably inserted is coupled to each other, and the valve operating chambers are connected to each other among a plurality of engine main body constituting members constituting the engine main body. is supported lifting one in which the specific engine body constituting member of two of the engine body structure member forming a, of the specific engine body constituting member, the axial The side walls of the rectangular side, the bulging portion bulging outward than other engine body constituting member which is coupled to the particular engine body constituting member is formed integrally with the other engine of the specific engine body constituting member The actuator is supported by an actuator support portion formed in the bulging portion so as to be flush with the coupling surface to the main body constituent member, and on the side wall of the other engine main body constituent member on the same side as the bulging portion. Is provided such that a plurality of boss portions through which a fastening member for fastening at least a part of the plurality of engine body constituting members is inserted bulge outward, and two of the plurality of boss portions adjacent to each other are provided. said actuator therebetween boss portion, the is disposed along the side wall of the other engine body constituting member, the output of the disposed within the bulging part actuator The rotation lever for transmitting the valve operating mechanism is pivotally supported by the specific engine body constituting member, the output shaft of the one end the actuator of the turning lever and the outer end of the other end the rod The output shaft, the turning lever, and the rod are arranged so as to exist on the same straight line extending along the cylinder axis of the engine body when viewed in a projection plane orthogonal to the camshaft. This is a first feature.

According to the second aspect of the invention, in addition to the configuration of the first feature, the bulging portion is disposed between the two boss portions when viewed in a projection plane orthogonal to the cylinder axis. It shall be the.

Further , in addition to the first or the second feature, the present invention provides the actuator, the engine valve disposed between the cylinder heads which are the specific engine main body constituting member so as to be opened and closed, A third feature is that a spark plug attached to the cylinder head is disposed.

Furthermore, in addition to any one of the first to third features, the present invention provides a slide cam capable of changing the operating characteristics of the engine valve by engaging and disengaging the rocker arm with the valve mechanism interlocked with the engine valve. The slide cam is supported by the camshaft so as to be axially slidable and non-rotatable relative to the camshaft, and is connected to the movable member so as to follow and move in the axial direction.

  The crankcase 11, the cylinder block 12, and the head cover 13 according to the embodiment correspond to the engine main body constituting member, the cylinder heads 13 and 109 correspond to the specific engine main body constituting member of the present invention, and the exhaust valve 25 according to the embodiment is provided. Corresponding to the engine valve of the present invention, the solenoid 64 of the embodiment corresponds to the actuator of the present invention.

  According to the first feature of the present invention, the specific engine main body constituting member is integrally formed with a bulging portion bulging outward from the other engine main body constituting member, and the actuator support formed in the bulging portion is formed. Since the actuator is supported by the part, a dedicated member separate from the engine main body for arranging the actuator is unnecessary, and the number of parts can be reduced. In addition to the actuator, the specific engine body component member supports a valve mechanism, and a pivot lever that transmits the output of the actuator to the valve mechanism is pivotally supported. The displacement of the coupling portion of the mechanism can be reduced without requiring strict dimensional control, and the actuator support portion is flush with the coupling surface of the specific engine body constituent member to the other engine body constituent member. Processing of the support portion can be facilitated.

Further , since the actuator is disposed along the side wall of the other engine main body constituent member coupled to the specific engine main body constituent member, the actuator can be arranged by effectively utilizing the space on the side of the engine main body . Furthermore , since the actuator is arranged between two adjacent bosses among the plurality of bosses provided on the side wall of the other engine body constituent member and bulging outward, the actuator is protected by the other engine body constituent member. It is Ru can.

Further, according to the third feature of the present invention, since the actuator and the spark plug are arranged so that the engine valve is sandwiched between them, it is possible to secure a space for arranging the actuator so as to avoid interference with the spark plug. it can.

1 is a longitudinal sectional view of a main part of an engine of Example 1. FIG. FIG. 2 is a sectional view taken along line 2-2 of FIG. FIG. 3 is an enlarged view of a portion indicated by an arrow 3 in FIG. 2. FIG. 4 is a view taken in the direction of arrow 4 in FIG. 3. FIG. 5 is a sectional view taken along line 5-5 in FIG. It is a figure which shows the valve opening lift characteristic of an intake valve and an exhaust valve. FIG. 7 is a cross-sectional view taken along line 7-7 in FIG. FIG. 8 is a cross-sectional view taken along line 8-8 in FIG. 2. FIG. 9 is a sectional view taken along line 9-9 in FIG. 2. FIG. 10 is an enlarged cross-sectional view taken along line 10-10 of FIG. 3 in a decompressed-off 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. FIG. 4 is a cross-sectional view corresponding to FIG. It is a 14 arrow line view of FIG. It is sectional drawing corresponding to FIG. 2 of a reference example .

  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 FIGS. 1 and 2, an engine body 10 of this engine is mounted on, for example, a motorcycle. Is constituted by connecting a plurality of engine body constituting members, a crankcase 11, a cylinder block 12, a cylinder head 13 and a head cover 14, to each other, and the cylinder block 12 has a cylinder bore 16 into which a piston 15 is slidably fitted. And a cylinder head 13 that is coupled to the crankcase 11 and forms a combustion chamber 17 facing the top of the piston 15 between the cylinder block 12 and the cylinder block 12. A head cover 14 is coupled to the cylinder head 13 from the opposite side. That.

  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. 3, the intake valve 24 and the exhaust valve 25 are driven to open and close by a valve mechanism 29A housed in a valve chamber 28 formed between the cylinder head 13 and the head cover 14. The valve mechanism 29A 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 an exhaust side that are supported by the cylinder head 13 with an axis parallel to the camshaft 32. The intake shafts 36, 37, the intake side rocker arm 38 swingably supported by the intake side rocker shaft 36 so as to open and close the intake valve 24 following the intake cam 30, and the exhaust cam 31, the slide An exhaust-side rocker arm 39 that is swingably supported by an exhaust-side rocker shaft 37 so as to open and close the exhaust valve 25 by following the cam 33 or the decompression cam 35 of the decompression means 34, and a shaft within the camshaft 32. The rod 59 is inserted so as to be movable in the direction, 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.

  Focusing on FIG. 1, the intake cam 30 and the exhaust cam 31 have arcuate base circles 30a and 31a centered on the axis of the camshaft 32 and outward of the base circles 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 which is in rolling contact with the intake cam 30 is pivotally supported at one end portion of the intake side rocker arm 38 supported so as to be swingable by the intake side rocker shaft 36, and an intake valve is provided at the other end portion of the intake side rocker arm 38. A tappet screw 53 abutting on the stem end 24a of 24 is screwed together so that the advance / retreat position can be adjusted.

  In FIG. 4, the exhaust side rocker arm 39 includes a support cylinder part 39a that is rotatably supported by the exhaust side rocker shaft 37, a first arm part 39b extending from the support cylinder part 39a to the exhaust valve 25 side, A second arm portion 39c extending from the support tube portion 39a to the camshaft 32 side is integrally provided. The support cylinder portion 39a is disposed between a pair of rocker shaft support portions 13a and 13b provided on the cylinder head 13 with a space therebetween, and is supported on the rocker shaft support portions 13a and 13b. The rocker shaft 37 is inserted into the support cylinder portion 39a.

  A tappet screw 54 as a valve connecting portion that is linked and connected to the exhaust valve 25 is screwed to the tip of the first arm portion 39b so as to contact the stem end 25a of the exhaust valve 25, and this tappet screw. 54 can adjust the forward / backward position.

  A cam contact portion 55 that can contact the exhaust cam 31, the slide cam 33, and the decompression cam 35 is provided at the tip of the second arm portion 39c. The cam abutting portion 55 abuts the roller 56 pivotally supported at the tip of the second arm portion 39c so as to abut against the exhaust cam 31 and the slide cam 33, and the decompression cam 35 of the decompression means 34. It comprises an abutting portion 39d (see FIGS. 1 and 3) integrally provided at the tip of the second arm portion 39c so as to be adjacent to the roller 56, and at least the camshaft 32 side of the abutting portion 39d. 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.

  Thus, the width W of the cam contact portion 55 in the direction along the axis of the camshaft 32 and the exhaust side rocker shaft 37 is contacted from the end surface of the roller 56 opposite to the intake side rocker arm 38. Up to the end surface of the portion 39d on the intake side rocker arm 38 side, one end portion of the cam contact portion 55, that is, the end surface 56a opposite to the intake side rocker arm 38 of the roller 56, is one end surface of the support cylinder portion 39a. 39aa, that is, it is located inward in the axial direction from the end face on the rocker shaft support portion 13a side.

  The slide cam 33 is in the vicinity of the exhaust cam 31 and is in contact with the roller 56 in the cam contact portion 55 of the exhaust rocker arm 39 (the position indicated by the solid line in FIGS. 3 and 4). Between the camshaft 32 and a non-operating position (a position indicated by a chain line in FIGS. 3 and 4) that avoids contact with the roller 56 at the cam contact portion 55 of the exhaust side rocker arm 39. The camshaft 32 is fitted and supported on the outer periphery of the camshaft 32 while allowing the camshaft 32 to move in the axial direction and disabling relative rotation around the axis of the camshaft 32.

  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 moves to the operating position where the cam contact portion 55 of the exhaust side rocker arm 39 contacts the roller 56, the exhaust side rocker arm 39 opens the exhaust valve 25 by the high position portion 31b of the exhaust cam 31. The valve closing state is maintained by contacting the base circular portion 31a of the exhaust cam 31 after rotating so as to be actuated. However, as shown in FIG. 6, at the final stage when the intake valve 24 is closed. The exhaust rocker arm 39 is slightly rotated so that the exhaust valve 25 is slightly opened by the high position portion 33b of the slide cam 33. 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 at the cam contact portion 55 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 opened / closed in an operating manner corresponding to the cam profile of the exhaust cam 31. 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.

  Moreover, at the non-operating position of the slide cam 33, as shown by the chain line in FIG. A first end surface 33c facing the exhaust cam 31 side is disposed, and a second end surface 33d opposite to the first end surface 33c is disposed outward from the one end surface 39aa of the support tube portion 39a. In the operating position, as shown by the solid line in FIG. 4, the second end surface 33d of the slide cam 33 is disposed inward of the one end surface 39aa of the support cylinder portion 33d.

  Thus, the movement range W1 of the first end surface 33c of the slide cam 33 is set to a range that straddles the end surface 56a of the roller 56, and the movement range W2 of the second end surface 33d of the slide cam 33 is the one end surface of the support cylinder portion 39a. It is set to a range straddling 39aa.

  Moreover, as shown in FIG. 4, a straight line passing through the contact point P of the tappet screw 54 to the stem end of the exhaust valve 25 of the tappet screw 54 and the axial center CP of the support cylinder portion 39a in the exhaust side rocker arm 39 is It passes through the slide cam 33 in the operating position in contact with the roller 56, and the slide cam 33 in the operating position in contact with the roller 56 of the cam contact portion 55 and the tappet screw 54 to the exhaust valve 25. The contact portion is disposed at a point-symmetrical position with respect to the axial center CP of the support cylinder portion 39a.

  Further, at least one of the facing surfaces of the slide cam 33 and the exhaust cam 31 is provided with a protrusion or a step portion that prevents the slide cam 33 from closely contacting the exhaust cam 31. In the first embodiment, as shown in FIG. In this way, a plurality of protrusions 31c are integrally projected on the end surface of the exhaust cam 31 on the slide cam 33 side.

  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. 5, 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.

  The rod 59 is driven in the axial direction by the rod driving means 63 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 mechanism 29A. The rod driving means 63 includes a solenoid 64 that is an actuator that is attached to the engine body 10 so as to exert power for operating the valve mechanism 29A so as to change the operating characteristics of the exhaust valve 25, and And a rotation lever 67 that transmits the output of the solenoid 64 to the rod 59 of the valve operating mechanism 29A.

  The cylinder head 13 and the head cover that form a valve operating chamber 28 among the crankcase 11, the cylinder block 12, the cylinder head 13, and the head cover 14, which are a plurality of engine body constituting members that are coupled to each other. 14 is a specific engine main body constituting member, in the first embodiment, the valve head mechanism 29A is supported by the cylinder head 13 and is expanded outwardly from the cylinder block 12 coupled to the cylinder head 13. A protruding portion 13c is integrally formed, and the solenoid 64 is supported by an actuator supporting portion 91 formed in the bulging portion 13c so as to be flush with the coupling surface 90 of the cylinder head 13 to the cylinder block 12. Moreover, the solenoid 64 is disposed at a position sandwiching the exhaust valve 25 and the intake valve 24 between the ignition plug 23 and is attached to the actuator support 91 by a plurality of bolts 68.

  Referring also to FIG. 7, the rotation lever 67 has one end connected to the tip of the output shaft 65 provided in the solenoid 64 and the other end connected to the rod 59 so that the support shaft 66 is connected. The bulging portion 14a on the other end side of the rotating lever 67 is connected to the bulging portion 13c of the cylinder head 13 on the head cover 14. Formed.

  The connecting portion of the rotating lever 67 connected to the output shaft 65 of the solenoid 64 or the connecting portion to the rod 59, that is, the connecting portion to the rod 59 in the first embodiment, the rod 59 corresponding to the operation of the solenoid 64. An adjusting mechanism 92 for adjusting the amount of movement is provided, and the output shaft 65 of the solenoid 64 is in direct contact with one end of the rotating lever 67.

  Referring also to FIG. 8, the adjustment mechanism 92 includes a weld nut 93 fixed to the other end of the rotation lever 67, and a tappet screw that is screwed into the weld nut 93 and passes through the rotation lever 67. 94 and a stop nut 95 that is engaged with and engaged with the weld nut 93 by screwing into the tappet screw 94, and the tappet screw 94 contacts the rod 59. Thus, by loosening the locking nut 95, the axial advance / retreat position of the tappet screw 94 can be adjusted, whereby the amount of movement of the rod 59 corresponding to the operation of the solenoid 64 is adjusted.

  By the way, the cylinder head 13 and the head cover 14 are coupled with a gasket 96 interposed between a coupling surface 97 of the cylinder head 13 to the head cover 14 and a coupling surface 98 of the head cover 14 to the cylinder head 13. However, the adjusting mechanism 92 is disposed closer to the head cover 14 than the coupling surface 97 of the cylinder head 13.

  A driven sprocket 48 that constitutes a part of the timing transmission mechanism 47 includes a second ball bearing 45 that is one of the first and second ball bearings 44 and 45 interposed between the camshaft 32 and the cylinder head 13. The rotary lever 67 is disposed between the rotary lever 67 and is fixed to the camshaft 32 with a pair of bolts 99, 99, for example. The connecting portion to the rod 59, that is, the contacting portion of the tappet screw 94 to the rod 59 is spaced from the driven sprocket 48 on the side away from the camshaft 32, as shown by the chain line in FIG. Set to position.

  Referring also to FIG. 9, the solenoid 64 is disposed along the side wall of the cylinder block 12 and supported by the actuator support portion 91. The cylinder block 12 constitutes the engine body 10. Of the crankcase 11, the cylinder block 12, the cylinder head 13 and the head cover 14, through holes 101 are formed through which through bolts 100, which are a plurality of fastening members for fastening the crankcase 11, the cylinder block 12 and the cylinder head 13, are inserted. A plurality of boss portions 12a are provided so as to bulge outward, and the solenoid 64 is disposed between the boss portions 12a, 12a adjacent to each other among the boss portions 12a.

  According to such rod driving means 63, when the solenoid 64 is actuated to project the output shaft 65, the rotation lever 67 rotates in the clockwise direction of FIG. 2 against the spring force of the return spring 62. Then, the rod 59 is pushed in against the spring force of the return spring 62, and the slide cam 33 moves to the operating position where it comes close to the exhaust cam 31 and contacts the roller 56 in the cam contact portion 55 of the exhaust side rocker arm 39. Therefore, when the solenoid 64 is in an inoperative state, the slide cam 33 is separated from the exhaust cam 31 by the spring force of the return spring 62 to avoid contact with the roller 56 at the cam contact portion 55 of the exhaust side rocker arm 39. It will move to the inoperative position.

  Referring to FIGS. 10 and 11 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 to 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 31a of the exhaust cam 31 and abuts against the abutment 39d 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 And a decompression cam 35 that is coupled to the decompression weight 72 so as never contacts the abutment 39d of the rocker arm 39 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 decompression weight 72 so as to be coaxially connected to the housing recess 74. 31b is provided with a bottomed insertion hole 78 through which the decompression pin 71 can be inserted so as to be coaxial with the first and second through holes 76 and 77 and open 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 FIG. 3) 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 through hole 76 of the decompression pin 71, Separation from 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 35. 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, so that the exhaust side rocker arm 39 is exhausted. The decompression cam 35 causes the roller 56 to contact 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 slide cam 33 is supported on the camshaft 32 of the valve mechanism 29A so that the relative rotation and the axial movement are possible, and is parallel to the camshaft 32. A cam abutting portion 55 that can abut against the slide cam 33 on an exhaust-side rocker arm 39 having a support cylinder portion 39a that is rotatably supported by an exhaust-side rocker shaft 37 that is supported by the cylinder head 13 with a simple axis. And a tappet screw 54 that is linked to and connected to the exhaust valve 25, and supports one end portion of the cam contact portion 55, that is, the end surface 56a of the roller 56 opposite to the intake side rocker arm 38. The cam contact portion 55 is exhausted so as to be disposed inward in the axial direction from one end surface 39aa of the cylindrical portion 39a, that is, the end surface on the rocker shaft support portion 13a side. When the slide cam 33 is in a non-operating position, which is provided on the rocker arm 39 and moves away from the exhaust cam 31 to avoid contact with the cam contact portion 55, the intake air of the cam contact portion 55 A first end surface 33c facing the exhaust cam 31 side of the slide cam 33 is disposed between the end surface 56a opposite to the side rocker arm 38 and the one end surface 39aa of the support cylinder portion 39a, and the first end surface 33c opposite to the first end surface 33c is disposed. When the slide cam 33 is in the operating position where the two end surfaces 33d are arranged outward from the one end surface 39aa of the support cylinder portion 39a and move to the exhaust cam 31 side to contact the cam contact portion 55, the slide A second end surface 33d of the cam 33 is disposed inward of the one end surface 39aa of the support cylinder portion 39a.

  Therefore, the amount of movement of the slide cam 33 in the axial direction can be reduced, and the time required for switching when changing the operating characteristics of the exhaust valve 25 can be shortened. In addition, since the operating characteristics of the two different exhaust valves 25 are obtained by one exhaust-side rocker arm 39, the axial width of the exhaust-side rocker arm 39 becomes relatively large, and the axial direction of the camshaft 32 is aligned. Due to the relatively large distance between the tappet screw 54 and the cam contact portion 55, when the exhaust valve 25 is lifted by the slide cam 33, a load in the falling direction acts on the exhaust side rocker arm 39, and the cam Although the load on the contact portion 55 may be excessive, when the slide cam 33 is used, the second end surface 33d that is the outer end surface of the slide cam 33 is disposed on the inner side than the one end 39aa of the support cylinder portion 39a. Thus, the exhaust-side rocker arm 39 can be prevented from falling down.

  Further, at least one of the facing surfaces of the slide cam 33 and the exhaust cam 31 is provided with a protrusion or stepped portion that prevents the slide cam 33 from being closely attached to the exhaust cam 31. Since the plurality of protrusions 31c are integrally formed on the end surface on the slide cam 33 side, there is lubricating oil between the slide cam 33 and the exhaust cam 31 in a state where the slide cam 33 is moved close to the exhaust cam 31 side. Even so, it is possible to prevent the slide cam 33 from coming into close contact with the exhaust cam 31, and to ensure a smooth operation from the operating position of the slide cam 33 to the non-operating position.

  3, the decompression pin 71 that is a part of the decompression means 34 is configured to penetrate the exhaust cam 31, and the protruding portion of the decompression pin 71 from the exhaust cam 31 is used as the exhaust of the slide cam 33. It may be configured as a protrusion that prevents close contact with the cam 31, so that the close contact between the slide cam 33 and the exhaust cam 31 can be prevented with a simple structure.

  Further, the slide cam 33 in the operating position in contact with the roller 56 of the cam contact portion 55 and the contact portion of the tappet screw 54 with the exhaust valve 25 are point-symmetric with respect to the axial center CP of the support cylinder portion 39a. Since the slide cam 33 comes into contact with the roller 56 at the operating position, the reaction force from the exhaust valve 25 in the direction opposite to the load in the falling direction acting on the exhaust side rocker arm 25 from the slide cam 33 is exhausted. The exhaust rocker arm 39 can be prevented from falling over by acting on the side rocker arm 39.

  Further, the valve mechanism 29A is supported by the cylinder head 13 which is one of the cylinder head 13 and the head cover 14 which form the valve chamber 28 therebetween, and the bulging portion 13c which swells outward from the cylinder block 12 is supported. Is integrally formed, and a solenoid 64 is supported by an actuator support 91 formed in the bulging portion 13c, and a rotation lever 67 that transmits the output of the solenoid 64 to the valve mechanism 29A is rotatable to the cylinder head 13. Therefore, a dedicated member separate from the engine body 10 for disposing the solenoid 64 is not necessary, and the number of parts can be reduced. In addition to the solenoid 64, the cylinder head 13 supports a valve operating mechanism 29A and a rotating lever 67 that transmits the output of the solenoid 64 to the valve operating mechanism 29A. The valve mechanism 29A, the solenoid 64, and the rotation lever 67 are assembled to the head 13, and the shift of the connecting portion of the solenoid 64 and the valve mechanism 29A is reduced without requiring strict dimensional control without increasing the processing cost. The dimensional accuracy of each part from the solenoid 64 to the rod 59 can be increased. Moreover, since the actuator support portion 91 is flush with the coupling surface 90 of the cylinder head 13 to the cylinder block 12, the processing of the actuator support portion 91 can be facilitated.

  Further, since the solenoid 64 is disposed along the side wall of the cylinder block 12 and supported by the actuator support portion 91, the solenoid 64 can be disposed by effectively utilizing the space on the side of the engine body 10.

  A plurality of boss portions 12a through which through bolts 100 for fastening the crankcase 11, the cylinder block 12 and the cylinder head 13 are inserted are provided on the side wall of the cylinder block 12 so as to bulge outward. 64 is disposed between two boss portions 12a, 12a adjacent to each other among the plurality of boss portions 12a, so that the solenoid 64 can be protected by the cylinder block 12.

  In addition, since the solenoid 64 is supported by the actuator support portion 91 so as to be disposed between the spark plug 23 and the exhaust valve 25 and the intake valve 24, interference with the spark plug 23 is avoided. An arrangement space for the solenoid 64 can be secured.

  By the way, the valve operating mechanism 29A can change the operating characteristics of the exhaust valve 25 in accordance with the linear operation of the rod 59 provided in the valve operating mechanism 29A, and opens and closes the exhaust valve 25 to drive the solenoid 64. The output is transmitted to the rod 59 through the rotation lever 67. The connection portion of the rotation lever 67 to the solenoid 64 or the connection portion to the rod 59 is in accordance with the operation of the solenoid 64. An adjusting mechanism 92 that adjusts the amount of movement of the rod 59 is provided. In the first embodiment, the adjusting mechanism 92 is provided at the connecting portion of the rotating lever 67 to the rod 59. The operating amount of the rod 59 can be adjusted according to the operation of the solenoid 64 without increasing the dimensional accuracy of each part up to the rod 59, thereby reducing the cost. Rukoto can.

  Further, since the adjustment mechanism 92 is arranged on the head cover 14 side of the coupling surface 97 of the cylinder head 13 to the head cover 14, the adjustment work of the adjustment mechanism 92 can be easily performed with the head cover 14 removed from the cylinder head 13. Adjustment workability can be improved.

  The camshaft 32 is rotatably supported by the cylinder head 13 via first and second ball bearings 44 and 45 disposed at an interval in the axial direction thereof, and provides rotational power to the camshaft 32. A driven sprocket 48 around which a cam chain 50 for transmission is wound is disposed between the second ball bearing 45 and the rotating lever 67 and fixed to the camshaft 32, and the solenoid 64 is in an inoperative state. Since the connecting portion of the rotating lever 67 to the rod 59 is set at a position spaced apart from the driven sprocket 48 on the side away from the camshaft 32, the connection to the camshaft 32 is performed. Easy assembly of driven sprocket 48 without obstruction by second ball bearing 45 and pivot lever 67 It can be carried out.

  Further, the rod 59 is placed on the side of the rotating lever 67 between the rod 59 and the bolt 58 fixed to the end of the camshaft 32 on the side opposite to the side where the rotating lever 67 is disposed. Since the return spring 62 for biasing is interposed, it is possible to assemble the return spring 62 for biasing the rod 59 after the rotation lever 67 and the driven sprocket 48 are assembled, thereby improving the assemblability. be able to.

  A second embodiment of the present invention will be described with reference to FIG. 13 and FIG. 14, but the portions corresponding to the first embodiment are only given the same reference numerals and are not illustrated in detail.

  The valve mechanism 29B 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 cam profile of the exhaust cam 31 and the camshaft. A slide cam 33 mounted on the outer periphery of the shaft 32 so as to be movable in the axial direction so as not to be relatively rotatable; and a decompression means 34 mounted on the camshaft 32 so as to sandwich the exhaust cam 31 between the slide cam 33; The intake side and exhaust side rocker shafts 36 and 37 supported on the cylinder head 13 with an axis parallel to the camshaft 32, and the intake cam 30 are driven to open and close the intake valve 24. An intake-side rocker arm 38 that is swingably supported by the side rocker shaft 36, the exhaust cam 31, and the slurry The exhaust side rocker arm 103 swingably supported on the exhaust side rocker shaft 37 so as to open and close the exhaust valve 25 by following the decompression cam 33 or the decompression cam 35 of the decompression means 34, and the camshaft 32 moves in the axial direction. And a rod 59 that can be inserted, and is supported by the cylinder head 13.

  The exhaust side rocker arm 103 includes a support cylinder part 103a that is rotatably supported by the exhaust side rocker shaft 37, a first arm part 103b extending from the support cylinder part 103a toward the exhaust valve 25, and the support cylinder part 103a. And a second arm portion 103c extending toward the camshaft 32 side. The support cylinder portion 103a is disposed between a pair of rocker shaft support portions 13a and 13b provided on the cylinder head 13 with a space therebetween, and is supported on the rocker shaft support portions 13a and 13b. The rocker shaft 37 is inserted into the support cylinder portion 103a.

  A tappet screw 54 as a valve connecting portion that is linked and connected to the exhaust valve 25 is screwed to the tip of the first arm portion 103b so as to contact the stem end 25a of the exhaust valve 25, and this tappet screw. 54 can adjust the forward / backward position.

  A cam contact portion 104 that can contact the exhaust cam 31, the slide cam 33, and the decompression cam 35 is provided at the tip of the second arm portion 103c. The cam abutting portion 104 can abut on the exhaust cam 31 and can be abutted with the roller 56 pivotally supported at the tip of the second arm portion 103 c and the slide cam 33. The roller 56 is sandwiched between the contact portion 103d so that the contact portion 103d provided at the tip of the second arm portion 103c on one side and the decompression cam 35 of the decompression means 34 are contacted. A contact portion 103e provided at the tip of the two-arm portion 103c, and at least the end portion of the contact portions 103d and 103e on the camshaft 32 side as viewed from the direction along the axis of the camshaft 32. Or formed so as to protrude toward the camshaft 32 from the outer periphery.

  Thus, one end portion 104a of the cam contact portion 104 in a direction along the axis of the camshaft 32 and the exhaust side rocker shaft 37 is from one end surface 103aa of the support cylinder portion 103a, that is, the end surface on the rocker shaft support portion 13a side. Is also located axially inward.

  The slide cam 33 is close to the exhaust cam 31 and is in contact with the contact portion 103d of the cam contact portion 104 of the exhaust-side rocker arm 103 (position indicated by a solid line in FIGS. 13 and 14). Between the non-operating position (a position indicated by a chain line in FIGS. 13 and 14) that is separated from the cam 31 and avoids contact with the contact portion 103 d of the cam contact portion 104 of the exhaust rocker arm 103. The camshaft 32 is fitted and supported on the outer periphery of the camshaft 32 while allowing the camshaft 32 to move in the axial direction and disabling relative rotation around the camshaft 32 axis.

  Moreover, in the non-operating position of the slide cam 33, as shown by a chain line in FIG. 14, the exhaust cam 31 of the slide cam 33 is interposed between the one end portion 104a of the cam contact portion 104 and the one end surface 103aa of the support cylinder portion 103a. The first end surface 33c facing the side is disposed, and the second end surface 33d opposite to the first end surface 33c is disposed outward from the one end surface 103aa of the support cylinder portion 103a. As shown by the solid line in FIG. 14, the second end surface 33d of the slide cam 33 is disposed inward of the one end surface 103aa of the support cylinder portion 103a.

  Thus, the moving range W1 of the first end surface 33c in the slide cam 33 is set to a range straddling the one end portion 104a of the cam contact portion 104, and the moving range W2 of the second end surface 33d in the slide cam 33 is the support cylinder portion 103a. Is set in a range straddling one end face 103aa.

  Further, a straight line passing through the contact point P of the tappet screw 54 with the stem end of the exhaust valve 25 of the tappet screw 54 and the axial center CP of the support cylinder portion 103 a in the exhaust side rocker arm 103 is the contact of the cam contact portion 104. It passes through the slide cam 33 in the operating position in contact with the contact portion 103d, and the slide cam 33 in the operating position in contact with the contact portion 103d of the cam contact portion 104 and the exhaust valve of the tappet screw 54 The abutting portion with respect to 25 is disposed at a point-symmetrical position with respect to the axial center CP of the support cylinder portion 103a.

  The same effects as those of the first embodiment can be obtained by the second embodiment.

Reference example

Next, a reference example will be described with reference to FIG. 15, but the portions corresponding to the first embodiment and the second embodiment are indicated by the same reference numerals, and detailed description thereof is omitted.

  The engine main body 108 of this engine is mounted on, for example, a motorcycle. The engine main body 108 can freely slide a crankcase 11 (see Example 1) and a piston 15 which are a plurality of engine main body constituting members. A cylinder block 12 having a cylinder bore 16 to be fitted and coupled to the crankcase 11 and a combustion chamber 17 facing the top of the piston 15 are formed between the cylinder block 12 and the cylinder block 12. And a head cover 110 coupled to the cylinder head 109 from the side opposite to the cylinder block 12.

  A valve operating mechanism 29A accommodated in a valve operating chamber 28 formed between the cylinder head 109 and the head cover 110 is supported by the cylinder head 109, and one end of a hollow cam shaft 32 provided in the valve operating mechanism 29A. An opening 111 opposite to the camshaft 32 is provided in the cylinder head 109 so that the camshaft 32 can be inserted and removed, and a valve 112 is attached to the cover 112 detachably attached to the cylinder head 109 so as to close the opening 111. A solenoid 64 is attached so as to directly drive the rod 59 of the mechanism 29A. That is, the output shaft 65 of the solenoid 64 abuts on the rod 59 coaxially.

  In addition, the solenoid 64 is attached to the cover 112 so that the exhaust valve 25 and the intake valve 24 are sandwiched between the ignition plug 23 attached to the cylinder head 109.

According to this reference example , a dedicated member separate from the engine main body 108 for disposing the solenoid 64 is unnecessary, and the rod 59 is directly driven by the solenoid 64, so that the transmission between the solenoid 64 and the valve mechanism 29A is performed. A mechanism is unnecessary, and the number of parts can be reduced.

  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.

  For example, an actuator support portion that is flush with the coupling surface of the cylinder head 13 to the head cover 14 may be provided in the bulge portion formed in the cylinder head 13, and the bulge portion formed in the head cover 14 may be provided. An actuator support that is flush with the coupling surface of the head cover 14 to the cylinder head 13 may be provided.

DESCRIPTION OF SYMBOLS 10,108 ... Engine main body 11 ... Crank case 12 which is engine main body structural member ... Cylinder block 12a which is engine main body structural member ... Boss part 13, 109 ... Specific engine main body structural member Cylinder head 13c ... bulging part 14, 110 ... head cover 23 as engine body constituent member ... ignition plug 25 ... exhaust valve 28 as engine valve ... valve chamber 32 ... Camshafts 29A, 29B ... Valve mechanism 64 ... Solenoid 67 as actuator ... Rotary lever 90 ... Coupling surface 91 ... Actuator support 111 ... Opening 112 ... Cover

Claims (4)

A valve operating mechanism (29A, 29B) that has a camshaft (32) in a valve operating chamber (28) formed in the engine body (10) and drives the engine valve (25) so that its operating characteristics can be changed is provided. It is possible to use an engine in which an actuator (64) that is housed and exhibits power for operating the valve mechanisms (29A, 29B) so as to change the operating characteristics of the engine valve (25) is attached to the engine body (10). In the variable valve device,
The valve operating mechanism (29A, 29B) for changing the operating characteristics of the engine valve (25) by the movement of a rod (59) inserted into the hollow camshaft (32) so as to be axially movable from one axial side. However, among the plurality of engine body constituent members (11, 12, 13, 14) that are connected to each other to form the engine body (10), two engine bodies that form the valve chamber (28) between them. is supported lifting one in which the specific engine body constituting member components (13, 14) (13),
The side wall of the specific engine main body constituting member (13) on the one axial side swells outward from the other engine main body constituting member (12) coupled to the specific engine main body constituting member (13) . The bulging portion (13c) is integrally formed,
Actuator support part (91) formed in the bulging part (13c) in line with the joint surface (90) of the specific engine body constituent member (13) to the other engine body constituent member (12) The actuator (64) is supported by
A fastening member (100) that fastens at least a part of the plurality of engine body constituent members (11 to 14) on a side wall of the other engine body constituent member (12) on the same side as the bulging portion (13c). ) Are inserted so as to bulge outward, and the actuator is interposed between two boss portions (12a) adjacent to each other among the plurality of boss portions (12a). (64) is arranged along the side wall of the other engine body constituting member (12),
A rotating lever (67) disposed in the bulging portion (13c) and transmitting the output of the actuator (64) to the valve operating mechanism (29A, 29B) rotates around the specific engine body constituting member (13). Supported movably ,
One end of the rotating lever (67) is connected to the output shaft (65) of the actuator (64), and the other end is connected to the outer end of the rod (59).
The output shaft (65), the rotation lever (67), and the rod (59) extend along the cylinder axis of the engine body (10) when viewed in a projection plane orthogonal to the camshaft (32). the variable BenSo location of the engine, characterized in that it is arranged so as to lie on a straight line. The variable valve for an engine according to claim 1, wherein the bulging portion (13c) is disposed between the two boss portions (12a) when viewed in a projection plane orthogonal to the cylinder axis. apparatus. The actuator (64) and the cylinder head (13, 109) are arranged so that the engine valve (25) arranged to be openable and closable is sandwiched between cylinder heads (13, 109), which are constituent members of the specific engine body. 109. A variable valve operating system for an engine according to claim 1 or 2, wherein a spark plug (23) attached to 109) is disposed. The valve operating mechanism (29A, 29B) includes a slide cam (33) capable of changing the operating characteristics of the engine valve (25) by being engaged with and disengaged from a rocker arm (39) interlocked with the engine valve (25). The slide cam (33) is supported on the camshaft (32) so as to be axially slidable and relatively non-rotatable, and is connected to the movable member (59) so as to follow and move in the axial direction. The variable valve operating apparatus for an engine according to any one of claims 1 to 3.

Images