JP2013221495A - Roller rocker arm type three-dimensional cam continuous and stepless variable valve gear - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve combustion efficiency by performing a tappet clearance and synchronization (lift amount adjustment between cylinders) precisely and efficiently without re-disassembling valve gear system components until all of the valve gear system components are assembled and a head cover is attached thereto, preventing fretting corrosion, improving air suction efficiency, and reinforcing an intake tumble flow.SOLUTION: The valve gear includes: a cam lob 12 which integrally rotates with a cam shaft 11 and enables relative movement in an axial direction; and a roller rocker arm 20 (swing arm) which is pressed onto a cam surface to move a valve 31 forward and backward, wherein a lift quantity, working angle and timing of the valve 31 are controlled steplessly and continuously variably depending on accelerator opening degree and travelling situation. The lift height between cylinders, the swinging shaft directional position of the rocker arm 20 (swing arm) and the thickness of a horseshoe shape shim or the mutual phases of a pair of spacers with a tilting cam surface are varied for adjustment.

Description

The present invention relates to an internal combustion engine in a two-wheeled vehicle, an automobile, or the like, which is formed so that the height, the working angle, and the timing are continuously changed, rotates integrally with the camshaft, and is axially movable and presses against the cam surface. The present invention relates to a valve operating apparatus that includes a roller rocker arm (swing arm) that moves the valve back and forth, and continuously and continuously controls the valve lift amount, operating angle, and timing in accordance with the accelerator opening and the traveling state.

As a roller rocker arm type three-dimensional cam continuous variable valve operating device, a roller follower that makes line contact with the cam and follows the change of the contact line angle is provided between the swinging shaft portion and the valve pressing portion, and is a swing arm type. Patent Documents 1 and 2 are disclosed.
Japanese Patent Laid-Open No. 5-18221 JP 9-21305 A

Further, Patent Documents 3, 4, 5, and 6 are disclosed in which a roller follower that makes point contact with a cam is provided between a swinging shaft portion and a valve pressing portion and is a swing arm type.
JP 2004-19567 A JP 2004-76675 A JP 2005-133547 A JP 2006-70841 A

Further, Patent Documents 7 and 8 are disclosed in which lift amount adjustment (synchronization) between cylinders is adjusted by changing the axial position of the accelerator fork with respect to the accelerator shaft and changing the axial position of the cam lobe.
JP 2004-204728 A JP 2008-25486 A

Further, Patent Document 9 is disclosed as a method for preventing fretting corrosion wear caused by tapping on the outer surface of the roller follower when there is no lift.
JP 2008-25487 A

A mechanical continuous continuously variable valve operating device that has been put into practical use is that the reciprocating cam is lost by moving the center of the reciprocating cam or the position of the rotating cam follower using a rotating cam and a swinging reciprocating cam. In some cases, the lift and the working angle can be varied simultaneously, but the mechanism becomes complicated and the weight and cost are increased. In addition, the weight of the reciprocating motion part is increased, the mechanical loss is increased due to the decrease in rigidity, and high rotation is difficult. In addition, VVT is necessary to obtain an appropriate opening / closing timing, and due to the slow response speed, the response improvement due to the abolition of the throttle valve is negated. Furthermore, because the lift height is controlled by lost motion, the lift curve in the low lift range is determined by the lift curve at the maximum lift, making it difficult to obtain the optimum lift curve for the desired output. The ramp working angle and height are the same in the entire lift range, and the amount of ramp is larger in the low lift range, which hinders the pumping loss reduction effect.

In order to remedy these drawbacks, there has been proposed one using a three-dimensional cam. A direct hitting type that slides a roller follower that contacts the cam and advances and retracts the valve in the axial direction of the valve stem, and a roller follower installed on the rocker arm. There is a rocker arm type that swings. The former is more rigid and can reduce the weight of the reciprocating motion part, so it is possible to increase the rotation speed and reduce mechanical loss, but it requires a camshaft for each of intake and exhaust, which is disadvantageous in terms of cost. Therefore, it is necessary to increase the axial length of the cam or to reduce the R of the roller follower in the cam axial direction as a countermeasure. To lengthen the cam lobe, it is necessary to widen the cylinder pitch, which increases the size of the engine. If the roller follower R is decreased, the surface pressure increases, so it is necessary to reduce the valve opening and closing acceleration accordingly, and the opening time area decreases. Resulting in. In addition, since the cam is disposed above the valve shaft and the roller follower, there is a drawback that it is difficult to adjust the tappet clearance. The latter is slightly disadvantageous in terms of rigidity and weight of the reciprocating part. There is an advantage that it is easy to remove. Further, since the camshaft can come out in one, the cylinder head can be reduced in size, weight and cost.

A roller follower, which is in line contact with the cam and follows the change in the contact line angle, is provided between the swinging shaft portion and the valve pressing portion, as disclosed in Patent Documents 1 and 2 having some of the latter advantages described above. Although a swing arm type continuous variable valve system has been disclosed, the cam peak shape in the cam shaft direction needs to be a straight line, and there is a large limitation on the cam peak shape setting, and the optimal lift curve for each cam peak height There is a drawback that the timing and the amount of ramp cannot be set arbitrarily.
Patent Documents 3, 4, 5, and 6 in which the roller follower that makes point contact with the cam is provided between the swinging shaft portion and the valve pressing portion and has a swing arm type are disclosed as having the above-mentioned all advantages. However, the biggest reason for adopting a continuous variable valve system is to minimize the lift error between cylinders, which is an essential condition for obtaining a pumping loss reduction effect as a non-throttle valve by making the intake valve stepless lift. It is not possible to reliably perform both tappet clearance adjustment and synchronization (inter-cylinder lift adjustment).
Regarding tappet clearance adjustment, Patent Documents 1, 3, and 4 are shim-like steps and are difficult to adjust in the micron order. Patent Documents 2 and 5 adjust the screw, and Patent Document 6 displaces the rocker arm swinging shaft, which can be adjusted steplessly and can be adjusted in the micron order.
As for synchronization, Patent Documents 1, 3, 4, and 6 only provide accuracy or replace parts. Patent Documents 2 and 5 have no description of synchronization, but have a washer on the roller follower side or fork boss. Although it can be tuned with the required accuracy as a shim, it is not very efficient because it requires adjustment after disassembly of the valve system parts and requires adjustment.
Patent Documents 7 and 8 have been disclosed as adjusting the synchronization by changing the fork position of the accelerator shaft that slides the cam lobe. However, Patent Document 7 makes the fork slidable with respect to the accelerator shaft and finely adjustable. Although it can be adjusted with high accuracy, the lift varies during operation due to insufficient rigidity. Patent Document 8 changes the position with the nuts on both sides of the fork boss. There are difficult drawbacks.
In addition, by adopting a roller follower that makes point contact with the three-dimensional cam, fretting corrosion wear due to slight vibration hitting the cam and roller follower contact part due to clearance when there is no lift occurs, lift amount fluctuation due to shape change, tappet There is a problem that increases noise due to increased clearance, and as a countermeasure, a cylindrical surface is connected to the side of the spherical outer peripheral surface. When there is no lift, the cam and the roller follower are in line contact with the cylindrical surface to reduce the surface pressure and fretting corrosion wear. Patent Document 9 is disclosed, which, like Patent Document 9, moves the left and right valves at the arm tip extended on both sides of the roller follower. And the roller follower cylindrical surface acts to absorb alignment errors, so a cylindrical surface is provided. Effect out, but out effect can be provided a cylindrical surface becomes point contact because it strikes only across one point of the cylindrical surface by the error can not be absorbed alignment error when the rocker arm type.

The present invention has been made in view of the above-described problems. The cam lobe is formed so that the height, the working angle, and the timing are continuously changed, and rotates integrally with the camshaft and is relatively movable in the axial direction. In a valve operating apparatus that includes a roller rocker arm (swing arm) that is pressed against the cam surface to advance and retract the valve, and continuously and variably controls the lift amount, operating angle, and timing of the valve in accordance with the accelerator opening and the traveling state. After assembling the cylinder head to the cylinder, tappet clearance and tuning (adjustment of lift amount between cylinders) is precise without reassembling the valve system parts until all the valve system parts are assembled and before the head cover is assembled. In addition to making it possible to implement it efficiently, it is possible to apply fine vibration when there is no lift, which requires countermeasures by using a roller rocker arm (swing arm). To prevent fretting corrosion, reduce the angle of inclination of the intake port with respect to the cylinder axis, improve intake efficiency and combustion efficiency by strengthening the intake tumble flow, and further stepless continuous lift variable by 3D cam only on the intake side The purpose of this is to achieve SOHC and to reduce the size, weight and cost of the cylinder head.

The invention of claim 1 for solving the above-mentioned problems is formed such that the height, the working angle, and the timing are continuously changed on the cam surface inclined in the camshaft axial direction, and rotates integrally with the camshaft and axially. And a roller rocker arm (swing arm) that makes point contact with the cam surface and presses and moves the valve forward and backward, and slides the cam lobe in the camshaft axial direction according to the accelerator opening and travel conditions. In the valve operating apparatus that continuously and variably controls the lift amount, working angle, and timing of the valve, the lift height is adjusted by changing the position of the roller rocker arm (swing arm) in the swing axis direction. .
The invention of claim 2 is characterized in that, in the invention of claim 1, the position of the roller rocker arm (swing arm) in the swing axis direction is adjusted by a shim.
By adopting a roller rocker arm (swing arm) as a valve lifter in a continuously variable variable valve device using a three-dimensional cam, the rigidity and reciprocating part weight are slightly disadvantageous compared to the direct stroke type, but the cam ratio of the lever ratio And the inclination becomes weak, so that the amount of change in the operating angle can be increased, and the cam is displaced from the upper side of the valve shaft, so that the tappet clearance can be easily adjusted. Further, since the camshaft can come out in one, the cylinder head can be reduced in size, weight and cost.
However, since the roller rocker arm (swing arm) is used to increase the variation in the lift amount by the lever ratio, it is necessary to keep the axial clearance of the swing shaft as small as possible. It is realistic to adjust the clearance in a shim-like manner, and it becomes a stepwise clearance adjustment, but the cam crest inclination angle is small and changes stepwise by a lift difference of about 1/4 of the axial displacement. If the adjustment is performed with a difference of 0.01 mm, the lift amount can be adjusted to about 2.5 μm, and if the axial clearance is about 0.02 mm, the variation in the lift amount can be suppressed to about 5 μm. Adjusting the position of the roller rocker arm (swing arm) in the swing axis direction by adjusting the thickness by placing shims on both sides of the swing shaft of the roller rocker arm (swing arm). ) Is possible.

The invention of claim 3 is characterized in that the shim has a horseshoe shape, and the locking piece prevents the shim from coming off and rotating from the rocker arm shaft.
By making the shim into a horseshoe shape, it can be inserted into the rocker arm shaft while being assembled to the roller rocker arm (swing arm). By the previous state, tuning (cylinder lift amount adjustment) can be performed precisely and efficiently without re-disassembling the valve operating system parts. More accurate tuning can be achieved by attaching the cylinder head to the cylinder and adjusting the cylinder head after it is deformed.

According to a fourth aspect of the present invention, adjustment of the position of the roller rocker arm (swing arm) in the swing axis direction is performed by relatively rotating a pair of spacers arranged in the axial direction of the rocker arm shaft around the axis of the rocker arm shaft. Therefore, the dimension between the spacer outer surfaces in the rocker arm shaft axial direction is changed by the inclined cams provided on the mating surfaces, and the axial dimension is fixed by fixing the phase of the spacers with the locking piece. It is characterized by.
After the cylinder head is assembled to the cylinder and the cylinder head is deformed, the phase of the spacers are changed and fixed with the locking piece without reassembling and reassembling all valve system parts other than the locking piece. Roller rocker arm (swing arm) Axial clearance adjustment and synchronization (inter-cylinder lift adjustment) of the swing axis can be performed precisely and efficiently.

According to a fifth aspect of the present invention, in the first aspect of the present invention, the position of the roller rocker arm (swing arm) in the swing axis direction is fixed by the rocker arm shaft, and the rocker arm shaft is fixed in the axial direction by the accelerator shaft slide actuator unit. It is characterized by being in the vicinity of the fixed part to the cylinder head.
If the position of the roller rocker arm (swing arm) in the swing axis direction is fixed with the cylinder head or camshaft housing, the clearance of the swing shaft of the roller rocker arm (swing arm) increases due to the difference in thermal expansion caused by the difference in material. There is a problem that the valve lift amount varies, and the position of the roller rocker arm (swing arm) shifts in the swing axis direction, causing the valve lift amount to shift. The position of the roller rocker arm (swing arm) is fixed in the direction of the swing axis, and the position of the rocker arm shaft is fixed in the vicinity of the fixed part of the accelerator shaft slide actuator unit to the cylinder head. Clearance increase Suppressed while the deviation of the oscillation axis direction position of the roller rocker arm (swing arm) can be suppressed to a minimum, engine operation suppressing valve lift difference between the cylinders to a minimum.

Further, the invention of claim 6 is formed such that the height, working angle, and timing are continuously changed on the cam surface inclined in the camshaft axial direction, and rotates integrally with the camshaft and is relatively movable in the axial direction. The cam lobe is equipped with a roller rocker arm (swing arm) that makes point contact with the cam surface and is pressed to advance and retreat the valve, and by sliding the cam lobe in the camshaft axial direction according to the accelerator opening and travel conditions, In a valve operating device that continuously and continuously controls the working angle and timing, the intake and exhaust camshafts are arranged on both sides of the valve stem axis of one of the valves as viewed from the camshaft axial direction. It is arranged on the cylinder head mating surface side (lower side) with respect to the camshaft.
According to a seventh aspect of the present invention, in the sixth aspect of the present invention, the intake and exhaust camshafts are arranged on both sides of the exhaust valve stem axis when viewed from the camshaft axial direction, and the spark plug hole (injector hole) is taken into the intake air. It is characterized in that it is arranged substantially parallel to the intake valve stem shaft on the valve side.
In the case of a narrow angle valve engine, even if the roller rocker arm (swing arm) swing shaft is sucked and arranged outside the V valve bank as in Patent Document 4, the angle of the intake port relative to the cylinder shaft can be reduced, and the cylinder head Although the suction and exhaust direction widths can be narrowed, in a standard intake and exhaust valve shaft V-bank engine, the angle of the intake port with respect to the cylinder shaft is large, and the cylinder head suction and exhaust direction widths are widened. When the intake and exhaust camshafts are viewed from the camshaft axial direction, they are arranged on both sides of the exhaust valve stem axis, and the ignition plug hole (injector hole) is arranged on the intake valve side substantially parallel to the intake valve stem axis. The angle of the intake port with respect to the cylinder shaft can be reduced, the intake efficiency and tumble flow can be improved, and the spark plug hole (injector hole) does not interfere, so the left and right exhaust valves on the exhaust port side that require cooling from the intake port side It becomes easy to provide a water passage between the exhaust ports near the valve seat.

The invention according to claim 8 is the invention according to claims 6 and 7, wherein the cylinder head and the lower camshaft housing are arranged with respect to the shaft center of the camshaft outside the suction and exhaust valve shaft V bank and the shaft center of the rocker arm shaft inside the V bank. It is characterized by having a mating surface.
By using the rocker arm shaft axis center as the mating surface of the cylinder head and the lower camshaft housing, the rocker arm shaft can be tightened without radial clearance by assembling the lower camshaft housing, and the rocker arm flutter can be suppressed and the valve lift amount accordingly. Therefore, the intake air amount can be controlled more accurately by adopting it on the intake side.
In addition, because of the ease of processing, the cylinder head and lower camshaft housing mating surface is the cylinder head cover mating surface, so the center of the camshaft shaft (rocker arm shaft shaft) near the cylinder head mating surface is the cylinder head cover. By using the mating surfaces, the cylinder head height that requires a thick metal material can be reduced, the cylinder head width in the intake and exhaust directions can be reduced, and the cylinder head can be made smaller and lighter.

Further, the invention of claim 9 is the invention of claims 6, 7, 8, 13 and 16, wherein the axis center of the accelerator shaft and the axis center of the camshaft in the V bank are arranged between the lower camshaft housing and the upper camshaft housing. It is characterized by a mating surface.
After the camshaft unit outside the V bank and the rocker arm unit in the V bank excluding the horseshoe shim are assembled to the cylinder head in the lower camshaft housing, the accelerator shaft is adjusted when adjusting the tappet clearance of the valve sandwiched between the intake and exhaust cam units. The unit is not assembled and does not get in the way, and after adjusting the tappet clearance, the accelerator shaft unit and camshaft unit in the V bank can be assembled, so that all the valve system parts are assembled and before the head cover is assembled. Thus, it is possible to perform the synchronization (adjustment of lift amount between cylinders) precisely and efficiently without re-disassembling the valve system parts.

The invention of claim 10 is characterized in that, in the inventions of claims 6 and 7, the vicinity of the tip of the left and right valve lift arms of the intake roller rocker arm is connected.
By connecting, the shape of the rocker arm becomes a square shape and the rigidity is improved, and the lift amount at the center of the left and right adjustment screws after assembling all valve system parts during synchronization (adjustment of lift amount between cylinders) Measurement is possible, and the average value of the left and right valve lifts can be measured, so that the cylinder lift amount can be adjusted more accurately.

Further, the invention of claim 11 is formed such that the height, working angle, and timing are continuously changed on the cam surface inclined in the camshaft axial direction, and rotates integrally with the camshaft and is relatively movable in the axial direction. Equipped with a cam lobe and a roller rocker arm (swing arm) that makes point contact with the cam surface and pushes it back and forth to move the valve back and forth. In a valve operating system that uses a roller swing arm that continuously and variably controls the working angle and timing, and the exhaust valve is in line contact with and pressed against the flat cam surface, the suction and exhaust cams are mounted on the same camshaft. And an exhaust cam is arranged on the side where the intake cam lobe slides to the maximum lift side.
When the intake cam lobe slides to the maximum lift side, the cam crest of the intake cam lobe close to the exhaust cam becomes the low lift side cam crest and is low, so the intake cam lobe is in the roller swinger support arm of the exhaust swing arm and the camshaft axial direction. Since it is difficult to contact even if it overlaps, the amount of sliding of the intake cam lobe can be increased accordingly, the inclination of the cam crest can be reduced, and more precise lift control becomes possible.

The invention of claim 12 is characterized in that, in the invention of claim 11, the base circle diameter of the exhaust cam is made larger than the base circle diameter of the intake cam lobe.
Even if the height of the cam crest on the low lift side of the intake cam lobe is set higher, it is difficult to contact the roller follower support arm of the exhaust swing arm and the cam shaft in the axial direction, and the roller follower support arm The outer shape can be made closer to the roller follower diameter, and the strength and rigidity can be improved.

According to a thirteenth aspect of the present invention, in the eleventh aspect of the present invention, the camshaft is provided in the suction and exhaust valve V bank near one of the valves, the rocker arm shaft is one, and the camshaft is on the cylinder head mating surface side The camshaft side valve is a swing arm having a roller follower between the pressing portion and the swinging shaft portion, and the other valve is a pressing portion and a roller. The rocker arm having a swinging shaft portion between the followers is advanced and retracted, and the center of the rocker arm shaft is used as a mating surface of the cylinder head and the lower camshaft housing.
By disposing the camshaft and rocker arm shaft in the intake and exhaust directions, the cylinder head width in the intake and exhaust directions becomes wider, but the cylinder head height can be reduced, and the cylinder head and lower camshaft are centered on the rocker arm shaft axis. By using the mating surface of the housing, it is possible to tighten the rocker arm shaft without radial clearance by assembling the lower camshaft housing. By doing so, more accurate intake air amount control can be performed.
Also, the camshaft and rocker arm shaft are combined into one, so that the cost and weight can be reduced by reducing the number of iron parts, and the cylinder head and lower camshaft housing mating surface is the cylinder head cover mating surface for ease of processing. Therefore, by using the center of the rocker arm shaft near the cylinder head mating surface as the cylinder head cover mating surface, the cylinder head height that requires a thick metal material is reduced and the cylinder head is reduced in size and weight. In addition, the angle of the intake port with respect to the cylinder shaft can be reduced, and the intake efficiency and the tumble flow can be improved.

The invention of claim 14 is characterized in that, in the invention of claim 13, the valve pressing portion is an adjusting screw, and the accelerator shaft is disposed on the opposite side of the camshaft with respect to the valve stem axis.
Adjustment screw adjustment and tightening tool can be passed between the accelerator shaft and camshaft. Tappet without reassembling the valve system parts before assembling all valve system parts and mounting the head cover Clearance adjustment can be performed precisely and efficiently.

According to a fifteenth aspect of the present invention, in the thirteenth aspect of the present invention, in the intake / exhaust rocker arm, the swing shaft portion is divided into left and right portions in the axial direction, and the roller follower arm is provided on one of the divided swing shaft portions. And a portion of the left and right valve lift arms near the tip, and one of the rocking shafts of the other rocker arm is disposed between the divided rocking shafts.
Since the two rocker arm swinging shafts that lift the valve can have a long span, fluctuations can be suppressed, fluctuations in the contact position between the 3D cam and the roller follower, and fluctuations in the left and right valve lift can be reduced, and the total lift of the left and right valves Can reduce the variation. In particular, on the intake side, the intake amount is controlled by the lift amount of the valve and the output is controlled. Therefore, it is essential to keep the variation in the lift amount small.
Also, by arranging one rocking shaft part of the other rocker arm between the divided rocking shaft parts, the total rocking shaft part width when two rocker arms are assembled is one rocker shaft of one rocker arm. This is the sum of the width of the part and the width of the outer side surface of the two rocking shafts of the other rocker arm, so that the shim can be adjusted without being affected by the pitch crossing between the rocking shafts. Axial flutter can be minimized.
Also, by connecting the vicinity of the tip of the left and right valve lift arms, the arm shape of the rocker arm becomes a square shape and the rigidity is improved, and at the same time (after adjusting the lift amount between cylinders), The lift amount can be measured at one central point of the adjusting screw, and the average value of the left and right valve lifts can be measured, so that the cylinder lift amount can be more accurately adjusted.

According to a sixteenth aspect of the present invention, in the eleventh aspect of the present invention, the camshaft is disposed in the vicinity of the center of the cylinder shaft when viewed from the camshaft axial direction, the rocker arm shaft is provided as one, and the camshaft is located on the cylinder head mating surface side. As seen from the camshaft axis direction, it is placed near the center of the cylinder axis, and both valves are advanced and retracted by a swing arm that has a roller follower between the valve pressing part and the swinging axis part, and the center of the rocker arm shaft axis is below the cylinder head. The mating surface of the camshaft housing is used.
Since the camshaft and the rocker arm shaft are arranged in the cylinder axis direction, the cylinder head height is higher than that of the invention of claim 13, but the cylinder head width in the intake and exhaust directions can be narrowed and a compact cylinder head can be obtained. By setting the center of the cylinder head and the lower camshaft housing as the mating surface, it is possible to tighten the rocker arm shaft without radial clearance by assembling the lower camshaft housing, and the rocker arm flutter can be suppressed and the valve lift amount can be reduced accordingly. Since it becomes smaller, the intake air amount can be controlled more accurately by adopting it on the intake side.
Also, the camshaft and rocker arm shaft are combined into one, so that the cost and weight can be reduced by reducing the number of iron parts, and the cylinder head and lower camshaft housing mating surface is the cylinder head cover mating surface for ease of processing. Therefore, by using the center of the rocker arm shaft near the cylinder head mating surface as the cylinder head cover mating surface, the cylinder head height requiring a thick metal material is reduced, and the cylinder in the suction and exhaust directions By reducing the head width, the cylinder head can be reduced in size and weight, and the angle of the intake port with respect to the cylinder axis can be reduced, so that the intake efficiency and the tumble flow can be improved.

According to a seventeenth aspect of the present invention, in the sixteenth and eighteenth aspects of the present invention, the suction and exhaust swing arms are provided with the swing shaft portion divided into left and right in the axial direction, and a roller is provided on one of the divided swing shaft portions. A follower arm portion is disposed, the vicinity of the left and right swing shaft portions of the intake swing arm is connected, and one swing shaft portion of the exhaust swing arm is disposed between the divided swing shaft portions.
Swing arm swinging shaft part that lifts the valve can have a long span, flutter is suppressed, fluctuation of contact position between 3D cam and roller follower and flutter of left and right valve lift can be reduced, and total lift of left and right valves The amount variation can be reduced.
In particular, on the intake side, the intake amount is controlled by the lift amount of the valve and the output is controlled. Therefore, it is essential to keep the variation in the lift amount small.
Also, by arranging one rocking shaft part of another rocker arm between the divided rocking shaft parts, the total rocking shaft part width when two rocker arms are assembled is one rocking shaft of one rocker arm. Since the width of the part and the width of the outer side surface of the two rocking shafts of the other rocker arm are added, shimming can be performed without being affected by the pitch crossing between the rocking shafts. Fluctuations in the direction of the dynamic axis can be minimized.
In addition, since the connecting part is in the vicinity of the left and right rocking shafts, it is not possible to measure the lift amount at one center of the left and right adjustment screws during synchronization (adjustment of the lift amount between cylinders), and measurement at both adjustment screw ends is not possible. Although necessary, the weight of the rocking tip is light and suitable for high-speed engines.

Further, the invention of claim 18 is formed such that the height, working angle, and timing are continuously changed on the cam surface inclined in the camshaft axial direction, and rotates integrally with the camshaft and is relatively movable in the axial direction. The cam lobe is equipped with a roller rocker arm (swing arm) that makes point contact with the cam surface and is pressed to advance and retreat the valve, and by sliding the cam lobe in the camshaft axial direction according to the accelerator opening and travel conditions, In a valve operating system that continuously controls the working angle and timing steplessly, an accelerator shaft that slides the cam lobe is provided coaxially with the cam shaft, and the cam lobe is fixed to the key fixed to the accelerator shaft in the axial direction of the cam shaft. While the rotation of the key and cam lobe relative to the camshaft is restricted by the long groove that is opened, the key and cam lobe Characterized in that the guide Mushafuto axis slide.
In the case where the accelerator shaft is arranged between the two camshafts as in the invention of claim 6, since the sliding resistance of the cam lobe is applied to both sides of the fork, the generated moment is small and the force to cause the accelerator shaft to bend. Since the resistance generated in the accelerator shaft bearing is small, it can be slid smoothly with small power. However, if the cam lobe slide on one camshaft is carried out with a fork fixed to the accelerator shaft, Since the sliding resistance becomes a moment as it is, the resistance force generated in the accelerator shaft bearing portion is large, and the power for sliding the cam lobe is increased. As a countermeasure, the generated moment can be greatly reduced by installing the accelerator shaft on the same axis as the camshaft.

Further, the invention of claim 19 is the invention of claim 18, wherein the cam lobe is provided with a clearance that can move minutely in the radial direction and the phase direction with respect to the key that is securely fixed so as not to move with respect to the accelerator shaft. It is characterized in that the movement is fixed to the minimum in the key axis direction.
By making the cam lobe move slightly in the radial direction and phase direction with respect to the key, it is possible to absorb the alignment error of the related parts and to make the cam lobe slide smoothly on the camshaft, and in the key axis direction. By fixing the movement to the minimum, the fluctuation of the lift amount can be suppressed to the minimum.

The invention of claim 20 is characterized in that, in the invention of claim 18, the rocker arm shaft is shared as a shaft for guiding the slide while regulating the rotation of the shaft of the accelerator shaft slide actuator.
The slide guide shaft of the accelerator shaft slide actuator becomes unnecessary.

The invention of claim 21 is characterized in that, in the invention of claim 18, the rocker arm shaft is shared as the bearing shaft of the idle gear of the drive gear train of the accelerator shaft slide actuator.
An idle gear shaft is not required.

The invention of claim 22 is formed such that the height, working angle, and timing are continuously changed on the cam surface inclined in the camshaft axial direction, and rotates integrally with the camshaft and is relatively movable in the axial direction. Equipped with a cam lobe and a roller rocker arm (swing arm) that makes point contact with the cam surface and pushes it back and forth to move the valve back and forth. In a valve operating system that uses a roller swing arm that continuously and variably controls the working angle and timing, and the exhaust valve is in line contact with and pressed against the flat cam surface, the suction and exhaust cams are on the same camshaft. And the exhaust cam is placed on the side where the intake cam lobe slides to the maximum lift side, overlapping the stroke range of the intake cam lobe Characterized in that was.
The stroke of the intake cam lobe can be increased, and a forced opening / closing cam can be adopted on the exhaust side.

The invention of claim 23 is characterized in that, in the invention of claim 22, the phases of the intake cam mountain and the exhaust cam mountain (open cam mountain in the forced opening / closing cam) of the portion overlapping the exhaust cam are substantially matched.
When the intake cam lobe is slid to the maximum lift side, the cam ridge of the intake cam lobe should face the part where the inner side is thickened to ensure the strength from the cam surface of the exhaust cam (open cam for forced opening cam) As a result, the increase in the diameter of the base circle of the exhaust cam can be minimized, and higher rotation and mechanical loss can be achieved.

The invention of claim 24 is the invention of claim 22, wherein the exhaust cam is forcibly opened and closed.
By forcibly opening and closing the exhaust side, tappet clearance adjustment can be performed without reassembling the valve system parts until all the valve system parts are assembled and the head cover is assembled after the cylinder head is assembled to the cylinder. And it is impossible to synchronize (lift adjustment between cylinders), but after adjusting the tappet clearance on the exhaust side with shim tone, until the state before assembling all valve system parts and assembling the head cover, Intake side tappet clearance adjustment and tuning (inter-cylinder lift adjustment) can be performed precisely and efficiently without re-disassembling the valve system parts.
If the working angle is the same, the opening area can be expanded by forced opening and closing. If the effective area (product of the opening area and the flow coefficient) is made equal, the working angle can be narrowed, increasing output, reducing fuel consumption, and reducing exhaust gas. Increased freedom of choice for countermeasures.

According to a twenty-fifth aspect of the invention, in the twenty-fourth aspect of the invention, when viewed from the direction parallel to the camshaft shaft, the cam contacting the roller follower on the spark plug hole (injector hole) side is moved away from the intake cam lobe. The cam contacting the roller follower without the (injector hole) is disposed close to the intake cam lobe.
The clearance between the valve lift arm on the spark plug hole (injector hole) side and the spark plug hole tube (injector hole tube) is easy to secure, and the valve lift arm on the side without the spark plug hole (injector hole) is connected to the rocker arm shaft shaft. Because it can be arranged in a position that overlaps the spark plug hole tube (injector hole tube) in the direction, the exhaust forced opening / closing cam can be adopted even in a small engine with a narrow cylinder pitch.

In the invention of claim 26, the height, the working angle, and the timing are formed so as to continuously change on the cam surface inclined in the camshaft axial direction, and the camshaft rotates integrally with the camshaft and is relatively movable in the axial direction. The cam lob is equipped with a roller rocker arm (swing arm) that makes point contact with the cam surface and is pressed to advance and retract the valve. In a valve gear that continuously controls the working angle and timing steplessly, the outer peripheral cross-sectional shape of the roller follower that makes point contact with the cam surface is the maximum outer diameter portion, where R is the alignment error between the camshaft unit and the rocker arm unit. Is set to the maximum R that can absorb the R And characterized in that a the barrel.
It is possible to prevent fretting corrosion wear when the rocker arm type tappet roller follower outer peripheral surface has no lift when the alignment is fixed and there is almost no function of absorbing alignment errors.

According to the present invention, there is provided a roller rocker arm (swing arm) that is pressed by a three-dimensional cam to advance and retract the valve, and continuously and variably controls the lift amount, operating angle, and timing of the valve in accordance with the accelerator opening and the traveling state. In the valve device, tappet clearance and synchronism (lift amount between cylinders) without re-disassembling the valve system parts until all the valve system parts are assembled and the head cover is assembled after the cylinder head is assembled to the cylinder. Adjustment) can be carried out precisely and efficiently, and the inclination angle of the intake port relative to the cylinder axis can be made smaller to improve intake efficiency and combustion efficiency by strengthening the tumble flow. By making the variable only on the intake side, SOHC is realized, and the cylinder head is reduced in size, weight and cost. It is possible to provide a Rudoben apparatus.

Hereinafter, preferred embodiments of a valve gear according to the present invention and an internal combustion engine including the same will be described with reference to the drawings. The valve gear according to the present invention is applicable to various gasoline engines and diesel engines mounted on motorcycles and automobiles.

The valve operating apparatus according to the first embodiment is a specific example of claims 1 to 10, and includes a camshaft unit 10, a rocker arm unit 20, and a valve unit 30 on the intake side, and the camshaft unit 10 _EX on the exhaust side. And a rocker arm unit 20 _EX and a valve unit 30 _EX .
Moreover, the accelerator shaft unit 40 which slides a cam lobe according to an accelerator opening degree and a driving | running | working condition is included. (See Figs. 1-1 to 6)

The intake camshaft unit 10 and the exhaust camshaft unit _10EX are arranged on both sides of the exhaust valve stem axis as viewed from the direction parallel to the camshaft shaft, and the intake camshaft unit 10 sucks and exhausts the exhaust valve shaft in the V bank. The camshaft unit 10 _EX is disposed outside the V bank. The intake rocker arm unit 20 and the exhaust swing arm unit 20 _EX are sucking, and the exhaust plug shaft unit 10 and 10 _{EX are on the} cylinder head mating surface side (lower side), and the ignition plug hole (injector hole) 1 _IG is on the intake valve unit 30 side Are arranged substantially parallel to the valve stem axis. (See FIG. 1-2).
Although it is necessary to dispose the swing shaft and dispose the intake port, in the case of a narrow-angle valve engine, the roller rocker arm (swing arm) swing shaft is sucked and disposed outside the exhaust valve shaft V bank as in Patent Document 4. However, the angle of the intake port relative to the cylinder shaft can be reduced and the cylinder head suction and exhaust direction width can be narrowed. However, in the standard intake and exhaust valve shaft V-bank engine, the angle of the intake port relative to the cylinder shaft is large. The width in the head suction and exhaust directions becomes wide. When the intake and exhaust camshafts are viewed from the camshaft axial direction, they are arranged on both sides of the exhaust valve stem axis, and the ignition plug hole (injector hole) is arranged on the intake valve side substantially parallel to the intake valve stem axis. Since there is no distracting valve parts on the outside of the intake side V bank, the angle of the intake port relative to the cylinder axis can be reduced, the intake efficiency and tumble flow can be improved, and the spark plug hole (injector hole) does not interfere Further, it becomes easier to provide a water passage between the exhaust ports near the valve seats of the left and right exhaust valves on the exhaust port side that need cooling from the intake port side. In this embodiment, the intake and exhaust camshafts are arranged on both sides of the exhaust valve shaft. However, if the intake port angle with respect to the cylinder shaft is increased for convenience of the intake system layout, the intake and exhaust camshafts are connected to the intake valve shaft. It may be arranged on both sides.

In the intake cam shaft unit 10, the intake camshaft 11 is rotatably supported by lower cam shaft housing 2 _L and upper cam shaft housing 2 _U. A cam lobe slide guide key 14 is inserted into and fixed to the key groove in the intake camshaft 11 at a phase corresponding to the ignition timing of each cylinder for each cylinder. Guide the slides. (See Fig. 1-2)
The intake cam lobe 12 is a three-dimensional cam formed such that its height, working angle, and timing change continuously on the cam surface inclined in the camshaft axial direction. As the slide slides, the lift amount and working angle increase and the timing also changes. It is set to be able to let you. Therefore, as shown in FIG. 1-1, the cam crest on the slide direction side becomes lower and gradually becomes higher as it becomes the opposite side in the slide direction. The inner race of the accelerator fork guide bearing 13 is press-fitted and fixed to the boss portion of the intake cam lobe 12 on the opposite side in the sliding direction. (See Fig. 1-1)
Fig. 5-10 shows an example of a lift curve when the wheel is cut from the low lift side to the high lift side at equal intervals in the axial direction. The lift characteristics (lift amount, working angle, timing) are changed constantly. The optimal lift amount, working angle, and timing for the output are selected.

The material of the camshaft is sufficient if carbon steel is heat-treated, but carburized steel is better if light weight, small size, and high rotation are aimed at. However, the cam lobe is a point contact with the roller follower, and the rocker arm type tends to increase the weight of the reciprocating motion part more than the direct hit type, so weight reduction is important, so the roller follower part is downsized. There is a need to. To that end, it is necessary to increase the allowable contact hertz stress with the cam, and the cam lobe must be made of carburized steel or bearing steel with a high allowable contact hertz stress, as well as special heat treatment and shot peening. It is desirable to improve the Hertzian stress resistance and the wear resistance of the roller wear.

Therefore impossible driven sprocket mounted to the center distance is short both the intake camshaft unit 10 and the exhaust camshaft unit 10 _EX, and a driven sprocket 15 is disposed only at one end of the intake camshaft 11, on the outside The gear train is provided.
A drive gear 17 is inserted together with a driven sprocket 15 to a spline shaft provided at one end of the intake camshaft 11 and fixed by a washer 18 bolt 19.
On the exhaust camshaft 11 _EX , a first driven gear 61 is fixed to the stepped shaft 11 _EXa portion by a key 63 and fixed in the axial direction by a washer 64 and a circlip 65. The second driven gear 62 rotatably attached to the boss 61 _EXa provided _{concentrically} with the stepped shaft 11 _EXa is _applied to the side of the first driven gear 61 with a spring 66 to change the phase. The first driven gear 61 and the second driven gear 62 sandwich the drive gear 17 so as to eliminate backlash and prevent a rattling noise. The second driven gear 62 and the spring 66 are prevented from coming off in the axial direction by a washer 64 and a circlip 65. A pin 67, which is a projection for a cam phase detection sensor, is press-fitted and fixed to the boss portion of the first driven gear 61. The phase is detected by the phase sensor unit 71 and the ignition timing is controlled by the output signal. A plug 16 is press-fitted and fixed to the other end of both camshafts to close the hollow hole to form an oil passage and to lubricate both camshaft bearings and cam lobes. (See Figures 1-1 and 2)
A cam chain is wound and mounted between a driven sprocket 15 and a drive sprocket formed at one end of a crankshaft (hereinafter not shown) by a chain guide, a chain tensioner, a chain adjuster, or the like.

The exhaust camshaft unit 10 _EX has the same basic configuration as the intake camshaft unit 10, but the specific specifications of the exhaust camlob 12 _EX differ from the intake camlob 12 as shown in FIG. 5-10. Although it is steplessly changed from the low lift side (two-dot chain line) to the high lift side (solid line), changes in lift amount, working angle, and timing are small.

As shown in FIG. 1-2, the intake rocker arm unit 20 and the exhaust swing arm unit 20 _EX are parallel to the camshaft shaft on the side closer to the cylinder head mating surface (lower side) than the intake and exhaust camshaft units 10 and _EX. As viewed from the direction, the intake rocker arm unit 20 is disposed on the side close to the intake valve unit in the intake and exhaust valve shaft V bank, and the exhaust swing arm unit 20 _EX is disposed outside the intake and exhaust valve shaft V bank. the axial center with the axial center of the intake rocker arm shaft 27 _iN of the _EX has a cylinder head 1 and the lower cam shaft housing 2 _L mating surface.
By using the center of the intake rocker arm shaft as the mating surface of the cylinder head and lower camshaft housing, it is possible to tighten the rocker arm shaft without radial clearance by assembling the lower camshaft housing. The variation in the amount is reduced, and the intake air amount can be controlled more accurately by adopting it on the intake side.
In addition, because of the ease of processing, the cylinder head and lower camshaft housing mating surface is the cylinder head cover mating surface, so the center of the camshaft shaft (rocker arm shaft shaft) near the cylinder head mating surface is the cylinder head cover. By using the mating surfaces, the height of the cylinder head that requires a thick metal material can be lowered, and the size and weight of the cylinder head can be reduced.

As shown in FIG. 1-3, the intake rocker arm 21 is rotatably supported by a pin 21-2 press-fitted and fixed to the tip end portion via a needle bearing 21-3, and is a roller follower 21- that makes point contact with each cam. 4 and the cam follower arm 21 _a with the valve lift arm 21 _b to the stem top of intake valve unit 30 forward and backward the pressed valve via the adjusting screw 22, when viewed from a direction parallel to the camshaft axis, L-shaped with integrally formed, a so-called rocker arm which is swingably supported in parallel arranged intake rocker arm shaft 27 _iN to the cam shaft axis, the axial center of the intake rocker arm shaft 27 _iN is the stem top surface in the valve axis direction It is arranged within the approximate stroke range. (See Fig. 1-2)
In all the embodiments, the roller follower 21-4 is provided with an oil groove on the side surface, and oil mist from the outside is guided to the needle bearing 21-3 and lubricated. (See Fig. 1-4)
In this embodiment, a needle bearing is employed as a roller follower bearing in order to reduce the weight of the roller rocker arm. In the case of a ball bearing or alignment bearing, there is no problem even if an oblique load is applied due to the inclination of the cam crest. It does not hold as a bearing. Therefore, it is necessary to minimize the side clearance between the roller follower and the cam follower arm so as to absorb the tilt of the roller follower by the crowning of the needle bearing. If the engine does not pursue high rotation, ball bearings and alignment bearings can be used, and the side clearance management between the roller follower and the cam follower arm can be omitted.
Also, in this embodiment, in order to minimize the amount of movement of the adjustment screw contact point with respect to the valve stem top surface in the direction perpendicular to the valve shaft and to suppress the force of turning the valve shaft, However, if the swing angle of the valve lift arm is small and the amount of movement of the contact point in the direction perpendicular to the valve shaft is small, or if the valve shaft has a large diameter and is strong against drooling such as a low-speed engine, the layout The swing axis may be removed slightly outside the stroke range.
Roller followers and needle bearings must have contact hertz stresses within the allowable range of cams and pins, and must be dimensioned according to the magnitude of acceleration to make the bearing life longer than the set endurance time. Therefore, it is necessary to reduce the size as much as possible from the viewpoint of high rotation. Therefore, it is common to use bearing steel or carburized steel as the material for roller followers, needle bearings, and pins. However, special heat treatment and shot peening have been added to improve hertz stress resistance and wear resistance. Should be planned.

Valve lift arm 21 _b is formed in a comb shape in the vicinity of the axial lateral valve axis of the pivot shaft portion 21 _c, (two right valve lift arm section 21 _bR and the left valve lift arm 21 _bL) Valve provided adjusting screw bosses 21 _d in the front end portion in the vicinity of the stem shaft, it is connected between the left and right boss arms 21 _e has a valve lift arm and the mouth-shape. (See Figure 1-3)
By connecting, the shape of the valve lift arm of the rocker arm becomes a square shape and the rigidity is improved. At the same time (the cylinder lift amount adjustment adjustment), all the valve system parts are assembled and lifted at one central position of the left and right adjustment screws. The amount can be measured, and the average value of the left and right valve lifts can be measured, so that the cylinder lift amount can be more accurately adjusted.

Horseshoe shims 25 on both outward thrust washer 24 stationary in the direction of the oscillation axis of the intake rocker arm 21 on both sides of the pivot shaft portion 21 _c, a circlip 26 or intake air locked in circlip grooves of the intake rocker arm shaft 27 _IN place the rocker arm shaft 27 _iN stepped portion 27 _INa, with adjusting the axial clearance of the pivot shaft portion 21 _c by adjusting the thickness of the horseshoe shims 25, adjusts the oscillation axis direction position of the intake rocker arm 21 To do.
Horseshoe shims 25 a recess 25 _a provided in a part, the recess 25 _a in the omission of the fixed shim engaging piece 51 with bolts 51-2 to face the projecting end 51 _a of the locking piece 51, to prevent rotation ing.
In this embodiment, in order to make the horseshoe-shaped shim and the locking piece small and light, the protrusion is placed in the recess to prevent rotation, but the contact shape between the horseshoe-shaped shim and the locking piece is linear. Etc. (See Figures 1-3 and 6-8)
Circlip 26 determines the phase at boss _1-5,2 LR _-2,2 LC -2 decided circlip phase provided in the cylinder head 1 and the lower camshaft housing _{2 L,} the cam lobe, the contact between the accelerator fork guide bearings Is preventing. Further, the locking piece 51 is positioned to prevent rotation at the time of bolt tightening at the steps 2 _LR -3, 2 _LC -3, and 2 _LL -3 provided in the lower camshaft housing 2 _L. (See Figures 1-7 and 8)
Adopting a roller rocker arm (swing arm) as a valve lifter is slightly disadvantageous in terms of rigidity and reciprocating part weight in comparison with the direct hitting type, but the cam angle is lowered and the inclination is weakened by the lever ratio, so the operating angle change is increased In addition, the cam is displaced from the upper side of the valve shaft, so that the tappet clearance can be easily adjusted.
However, since the roller rocker arm (swing arm) is used to increase the variation in the lift amount by the lever ratio, it is necessary to keep the axial clearance of the swing shaft as small as possible. It is realistic to adjust the clearance in a shim-like manner, and it will be a stepwise clearance adjustment, but the cam mountain inclination angle is small and changes stepwise by a lift difference of about 1/4 of the axial displacement. If the shim tone is 0.01mm difference, the lift amount can be adjusted around 2.5μ. If the axial clearance is about 0.02mm, the variation in the lift amount can be suppressed to around 5μ. The lift amount can be adjusted (tuned).
In addition, since the shim has a horseshoe shape, it can be inserted into the rocker arm shaft with the roller rocker arm (swing arm) assembled, so after assembling the cylinder head to the cylinder, assemble all valve system parts and cover the head cover. By the time before assembly, the tuning (inter-cylinder lift adjustment) can be performed precisely and efficiently without re-disassembling the valve system parts.

By fixing the position of the intake rocker arm 21 in the swing axis direction by relatively rotating the pair of spacers around the axis, the dimension between the outer surfaces is adjusted, and the phase between the spacers is fixed by the locking piece, with adjusting the axial clearance of the pivot shaft portion 21 _c, show the specific examples of claims 4 to adjust the oscillation axis direction position of the intake rocker arm 21 in Figure 1-10.
Placing a pair of spacers 24, 25 on either side of the pivot shaft portion 21 _c, place the circlip 26 or the intake rocker arm shaft _{27 IN} stepped portion _{27 INa} which engages the circlip groove in the outside air intake rocker arm shaft _{27 IN} and, by relatively rotating at least one of the spacers 24 and 25 around the axis of the intake rocker arm shaft 27 _iN, the inclined cam 24 _a, 25 a spacer outside of the rocker arm shaft axis direction by _a provided on the mating surface of each other as a side dimension between T changes, thereby adjusting the axial clearance of the pivot shaft portion 21 _c by adjusting the inter outer surface dimension T, adjusting the swinging axial position of the intake rocker arm 21.
The spacers 24 and 25 are provided with serrations 24 _b and 25 _b on the outer periphery, the front end protrusion 51 _a of the locking piece 51 is exposed, the locking piece 51 is fixed with a bolt 51-2, and the phase between the spacers is fixed. Fix the axial dimension with. (The cross-section BB in FIG. 1-10 is obtained by replacing the thrust washer 24 and the horseshoe shim 25 in FIG. 1-7 with spacers 24 and 25 with inclined cams.) In this embodiment, peaks of serrations 24 _b and 25 _b are obtained. The number t is 120, the inclination of the inclined cams 24 _a , 25 _a is set to 120 ° and the axial direction is 0.4 mm, and when the spacers 24, 25 are relatively displaced by one mountain, the change amount t of the outer surface dimension T becomes 0. It is 01 mm and can be adjusted with the same accuracy as a horseshoe shim. The inclined cam crests have three crests at 120 ° intervals in order to stably receive the axial load at three points, the adjustment angle is 90 °, and the outer surface adjustment dimension t is about 0.3 mm. This amount is sufficient for the swing axis position adjustment amount. However, depending on the machining accuracy of the related parts, it may be insufficient if clearance adjustment is included, but in that case, prepare a different spacer thickness and prepare the clearance in advance. Adjust it.
Circlip 26 determines the phase at boss _1-5,2 LR _-2,2 LC -2 decided circlip phase provided in the cylinder head 1 and the lower camshaft housing _{2 L,} the cam lobe, the contact between the accelerator fork guide bearings Is preventing. Further, the locking piece 51 is positioned to prevent rotation at the time of bolt tightening at the steps 2 _LR -3, 2 _LC -3, and 2 _LL -3 provided in the lower camshaft housing 2 _L.
After the cylinder head is assembled to the cylinder and the cylinder head is deformed, all the valve system parts other than the locking piece are assembled and disassembled, and the phase of the spacer is changed and fixed with the locking piece. Roller rocker arm (swing arm) Axial clearance adjustment and synchronization (inter-cylinder lift adjustment) of the swing axis can be performed precisely and efficiently.

The intake rocker arm shaft 27 _IN is clamped and clamped in a bearing hole provided in the cylinder head 1 and the lower camshaft housing 2 _L without radial clearance, and is provided in the vicinity of the housing 44-7 attachment of the accelerator shaft slide actuator unit 44. Cylinder head 1 and lower cam without axial clearance at part 27 _INa and bevel-shaped circlip 28 (the circlip is displaced in the axial direction by tilting the circlip groove on one side) It is assembled to the shaft housing 2 _L. (See Figures 1-1, 2, 3 and 6)
If the position of the roller rocker arm (swing arm) in the swing axis direction is fixed with the cylinder head or camshaft housing, the clearance of the swing shaft of the roller rocker arm (swing arm) increases due to the difference in thermal expansion caused by the difference in material. There is a problem that the valve lift amount varies, and the position of the roller rocker arm (swing arm) shifts in the swing axis direction, causing the valve lift amount to shift. The position of the roller rocker arm (swing arm) is fixed in the direction of the swing axis, and the position of the rocker arm shaft is fixed in the vicinity of the fixed part of the accelerator shaft slide actuator unit to the cylinder head. Clearance increase Suppress the deviation in the oscillation axis direction position of the roller rocker arm (swing arm) can be suppressed to a minimum, engine operation suppressing valve lift difference between the cylinders to a minimum.
The intake rocker arm shaft 27 _IN has a hollow structure, one end is plugged with a plug 27-2 to form a lubricating oil passage, and oil supplied through a lubricating oil passage formed in the cylinder head and the camshaft housing. , as well as lubricate the pivot shaft portion 21 _c of the intake rocker arm 21, needle bearing 21-3 and the cam crest portion, and the lubricating oil jets injected into the roller follower 21-4. (See Figures 1-3 and 6)

As shown in FIG. 1-4, the exhaust swing arm 21 _EX is a roller follower that is pivotally supported by a pin 21-2 that is press-fitted and fixed to the distal end portion via a needle bearing 21-3, and that makes point contact with each cam. The cam follower arm portion 21 _EXa having 21-4 is provided between the valve lift arm portion 21 _EXb and the swinging shaft portion 21 _EXc that presses the stem top portion of the exhaust valve unit 30 _EX through the adjustment screw 22 to advance and _{retract the} valve. A so-called roller swing arm that is integrally formed in a T-shape when viewed from a direction parallel to the camshaft shaft and is swingably supported by an exhaust rocker arm shaft 27 _EX disposed in parallel to the camshaft shaft. The axis center of 27 _EX is arranged within the stroke range of the stem top surface in the valve axis direction. (See Fig. 1-2)
In this embodiment, the amount of movement of the adjustment screw contact point with respect to the valve stem top surface in the direction perpendicular to the valve axis is small, so the layout is convenient (ensure the height of the lower camshaft housing, make the upper and lower mating surfaces parallel, and make the cylinder shaft perpendicular) ) The swing axis is near the maximum lift in the stroke range.

Valve lift arm _{21 EXB} is formed in a comb shape in the vicinity of the axial cam follower arm _{21 EXa} of the pivot shaft portion _{21 EXc,} two (right valve lift arm _{21 EXbR} and the left valve lift arm section _{21 EXBL} ) An adjusting screw boss 21 _EXd is provided at the tip near the valve stem shaft. (See Fig. 1-4)

The position of the exhaust swing arm 21 _{EX in} the swing axis direction is fixed by arranging a thrust washer and shim 24 _EX on both sides of the swing shaft portion _EXc , and adjusting the thickness of the exhaust swing arm 21 _EX between the exhaust rocker arm shaft bearings of the cylinder head 1. Adjust the clearance appropriately. The exhaust rocker arm shaft 27 _EX is inserted into a bearing hole provided in the cylinder head 1 and is prevented from coming off by a stopper bolt 29. Further, the exhaust rocker arm shaft 27 _EX has a hollow structure, forms a lubricating oil passage, and lubricates the swing shaft portion 21 _EXc of the exhaust swing arm 21 _EX with oil supplied through the lubricating oil passage formed in the cylinder head. At the same time, oil jet injection lubrication is applied to the needle bearing 21-3, the cam crest, and the roller follower 21-4. (See Fig. 1-4)
The exhaust lift curve has a small lift between the low output and high output, the working angle, and the timing difference, so the cam angle is small, the effect on the performance due to the lift curve difference is small, and there are variations in lift and differences between cylinders. Therefore, there is no need for synchronization (adjustment of lift amount between cylinders), and a simple structure is used to reduce costs.

Intake valve unit 30, as shown in Figure 1-2, comprises two intake valves 31 intake valve stem 31 _a is guided by the intake valve guide 1-3.
By the intake valve 31 is lifted, an air cleaner through the intake port 1 _IN, and air is controlled flow mainly by the valve lift amount is derived from the intake pipe (not shown), an injector into an intake passage or a combustion chamber ( A mixture with fuel sprayed from (not shown) is introduced into each cylinder.

The intake valve 31 is a valve stem 31 _a of the top conical split cotter 33 engages with the cotter groove around the cylindrical guide 34 _a on the flange lower surface having a taper portion that engages the cotter inside cylindrical portion The retainer 34 provided is engaged, and the valve guide 1-3 of the cylinder head 1 is guided by the cylindrical guide 34 _a and the valve guide 38 _a of the valve spring seat 38 between the valve spring seat 38 above the press-fitting portion. A valve spring 39 of a coil spring is accommodated and is assembled to the cylinder head 1 so as to be able to advance and retract. (See Fig. 1-2)

Note that the exhaust valve unit 30 _EX has the same basic configuration as the intake valve unit 30, and a description thereof will be omitted. However, specific specifications of the exhaust valve 31 _EX are different from those of the intake valve 31.
In this case, the combustion gas in the cylinder is exhausted through an exhaust pipe (not shown) via the exhaust port 1 _EX .

Axis center parallel to the both cam shafts, in was mating surfaces the axis center of the intake camshaft 11 vertical camshaft housing mating surface on between the accelerator shaft unit 40 and the intake cam shaft unit 10 and the exhaust camshaft unit 10 _EX And is supported so as to be slidable in the axial direction. (See Fig. 1-2)
Adjust the exhaust valve shaft tappet clearance before installing the accelerator shaft unit after assembling the intake rocker arm unit inside the V bank except the exhaust camshaft unit outside the V bank and the horseshoe shim to the cylinder head with the lower camshaft housing. Because there is nothing obstructing the upper part of the adjusting screw, adjustment of the box wrench type and the tightening tool can be used to adjust the tappet clearance precisely and easily. After adjusting the tappet clearance, the accelerator shaft unit and V bank By assembling the intake camshaft unit and then adjusting and tuning the intake valve tappet clearance, reassembling the valve system parts until all the valve system parts are assembled and before the head cover is installed. No synchronization (matching lift between cylinders) It can be carried out integer).

An accelerator fork 42 is press-fitted and fixed to the accelerator shaft 41, and its tip claw is engaged with the outer race groove of the accelerator fork guide bearing 13 to suck the exhaust cam lobes 12 and 12 _EX . An accelerator shaft slide actuator unit is provided on one end of the accelerator shaft 41. A joint bracket 43 is press-fitted and fixed on both ends of the T-shaped bracket in parallel with the accelerator shaft axis. A joint bracket 44-2 having bolt holes on both ends of a T-shaped bracket that is press-fitted and fixed to one end of a male screw shaft 44-1, and an accelerator shaft 41 and a male screw shaft 44-1. While absorbing the eccentricity of both shafts, the gap between both joint brackets is adjusted to the minimum and the double nut is fastened. The rotation of the male screw shaft 44-1 of the accelerator shaft slide actuator unit 44 is restricted by the bolt 43-2 at the tip of the T-shaped bracket and the accelerator fork 42 engaged with the outer race groove portion of the accelerator fork guide bearing 13. The male screw shaft 44-1 advances and retreats in the axial direction by the rotation of the screw boss portion 44-3.
The left accelerator fork 42 _L is provided with a groove for engaging the tip of the detection arm 73 of the accelerator shaft slide sensor 72, and the amount of slide of the accelerator shaft 41 is detected by the phase change of the detection arm 73 to control the accelerator motor 45. ing. (See Figure 1-5)

The accelerator shaft slide actuator unit 44 is fixed to the cylinder head 1 by a housing 44-7, and a driven gear 44-4 is fixed to a female screw boss portion 44-3 by a key 44-5 and a circlip 44-6. Female screw boss portion 44-3 bearing 44-8 _a, and is rotatably supported at 44-8 _b, bearing 44-8 _a are pressed into the female threaded boss portion 44-3, stage housing 44-7 Attached to beveled circlip 44-9 and fixed to housing 44-7 without any axial gap, and by using a four-point contact bearing, the axial backlash of female screw boss 44-3 is minimized. It is suppressed.
In this embodiment, a ball screw type is used to reduce mechanical loss, but a trapezoidal screw may be adopted.
A drive gear 45-2 fixed to the output shaft of the accelerator motor 45 fixed to the cylinder head 1 by a spline and a circlip 45-3 meshes with the driven gear 44-4, and an accelerator motor corresponding to the accelerator opening and the traveling state. rotation of the output shaft 45 is an accelerator shaft 41, that is, intake, is converted into a sliding motion of the exhaust cam lobe 12, 12 _EX. (See Figure 1-5)

An ignition plug hole tube (injector hole tube) 81 is inserted into a hole formed in the cylinder head 1 and the cylinder head cover 3 and sealed with an O-ring 82 to form an ignition plug hole (injector hole) 1 _IG. The intake valve unit 30 is disposed in a valve lift arm formed in a square shape of the intake rocker arm 21 substantially parallel to the intake valve shaft. (See Fig. 1-2)
Since the spark plug hole (injector hole) does not interfere, it is easy to provide a water passage between the exhaust ports near the valve seats of the left and right exhaust valves on the exhaust port side that need to be cooled from the intake port side.

The valve operating apparatus according to the second embodiment is a specific example of claims 11 to 15, and the first embodiment is a so-called DOHC provided with a three-dimensional camshaft and a rocker arm unit for both intake and exhaust. The side is changed from a three-dimensional cam to a flat cam, the suction cam is provided on the same camshaft, the exhaust cam is arranged on the side where the intake cam lobe slides to the maximum lift side, and the camshaft is placed near the suction of one valve. , Provided in the exhaust valve V bank, with a single rocker arm shaft, placed on the cylinder head mating surface side with respect to the camshaft, near the center of the cylinder shaft as seen from the camshaft axis direction, and the camshaft side valve is a pressing part The rocker arm has a roller follower between the swinging shaft part and the other valve is a rocker arm having the swinging shaft part between the pressing part and the roller follower It moved back and forth Te, a so-called SOHC which the rocker arm shaft axis center as the mating surface of the cylinder head and the lower cam shaft housing includes a cam shaft unit 10, the rocker arm unit 20, the intake valve unit 30, an exhaust valve unit 30 _EX. Moreover, the accelerator shaft unit 40 which slides a cam lobe according to an accelerator opening degree and a driving | running | working condition is included. (See Figures 2-1 to 5)
Of these, the description of the basically same one as in the first embodiment will be omitted or simplified as appropriate.
By disposing the camshaft and rocker arm shaft in the intake and exhaust directions, the cylinder head width in the intake and exhaust directions becomes wider, but the cylinder head height can be reduced, and the cylinder head and lower camshaft are centered on the rocker arm shaft axis. By using the mating surface of the housing, it is possible to tighten the rocker arm shaft without radial clearance by assembling the lower camshaft housing. By doing so, more accurate intake air amount control can be performed.
Also, the camshaft and rocker arm shaft are combined into one, so that the cost and weight can be reduced by reducing the number of iron parts. Therefore, by using the center of the rocker arm shaft near the cylinder head mating surface as the cylinder head cover mating surface, the cylinder head height that requires a thick metal material is reduced and the cylinder head is reduced in size and weight. In addition, there is no disturbing valve component arrangement outside the intake V bank, the angle of the intake port with respect to the cylinder axis can be reduced, and intake efficiency and tumble flow can be improved.

The camshaft unit 10 and the accelerator shaft unit 40 are arranged on both sides with respect to the exhaust valve stem axis when viewed from the direction parallel to the camshaft shaft. Are arranged outside the V bank. The rocker arm unit 20 is arranged on the cylinder head mating surface side (lower side) with respect to the camshaft unit 10, and the spark plug hole (injector hole) 1 _IG is arranged on the intake valve unit 30 side substantially parallel to the valve stem shaft. (See Figure 2-2)
In the case of a narrow angle valve engine, even if the roller rocker arm (swing arm) swing shaft is sucked and arranged outside the V valve bank as in Patent Document 4, the angle of the intake port relative to the cylinder shaft can be reduced, and the cylinder head Although the suction and exhaust direction widths can be narrowed, in a standard intake and exhaust valve shaft V-bank engine, the angle of the intake port with respect to the cylinder shaft is large, and the cylinder head suction and exhaust direction widths are widened. When the camshaft and the accelerator shaft are viewed from the camshaft axial direction, they are arranged on both sides of the exhaust valve stem axis, and the ignition plug hole (injector hole) is arranged on the intake valve side substantially parallel to the intake valve stem axis. Since there is no distracting valve parts on the outside of the intake side V bank, the angle of the intake port relative to the cylinder axis can be reduced, the intake efficiency and tumble flow can be improved, and the spark plug hole (injector hole) does not interfere Further, it becomes easier to provide a water passage between the exhaust ports near the valve seats of the left and right exhaust valves on the exhaust port side that needs to be cooled from the intake port side. In this embodiment, the camshaft and the accelerator shaft are arranged on both sides of the exhaust valve shaft. However, if the intake port angle with respect to the cylinder shaft is increased for convenience of the intake system layout, the intake and exhaust camshafts are connected to the intake valve shaft. It may be arranged on both sides.

In the camshaft unit 10, the cam shaft 11 is rotatably supported by lower cam shaft housing 2 _L and upper cam shaft housing 2 _U. A cam lobe slide guide key 14 is inserted into the key groove at a phase corresponding to the ignition timing of each cylinder for each cylinder, and the cam shaft 11 slides while regulating the phase of the cam lobe with respect to the cam shaft of the intake cam lobe 12. Is guiding.
The intake cam lobe 12 is a three-dimensional cam formed such that its height, working angle, and timing are continuously changed on a cam surface inclined in the camshaft axial direction. It is set to change. Therefore, as shown in FIG. 2A, the cam crest on the slide direction side becomes lower and becomes gradually higher as it goes to the opposite side in the slide direction. On the opposite side of the sliding direction, an inner race of the accelerator fork guide bearing 13 is press-fitted and fixed to the boss portion of the intake cam lobe. The exhaust cam 12 _EX is press-fitted and fixed to the side where the intake cam lobe 12 slides to the maximum lift side in a phase corresponding to the ignition timing of each cylinder. Further, the base circle diameter of the exhaust cam 12 _EX is set larger than the base circle diameter of the intake cam lobe 12. (See Figures 2-1 and 2)
(Example of lift curve is solid line in Fig. 5-10)
When the intake cam lobe slides to the maximum lift side, the cam crest of the intake cam lobe close to the exhaust cam becomes the low lift side cam crest and is low, so the intake cam lobe is in the roller swinger support arm of the exhaust swing arm and the camshaft axial direction. Since it is difficult to contact even if it overlaps, the amount of sliding of the intake cam lobe can be increased accordingly, the inclination of the cam crest can be reduced, and more precise lift control becomes possible. Also, by setting the exhaust cam base circle diameter larger than the intake cam lobe, the cam follower shaft and camshaft axial direction of the exhaust swing arm can be set even if the cam lift on the low lift side of the intake cam lobe is set higher. It is possible to make it difficult to contact even if they overlap, and the outer shape of the roller follower support part arm can be brought close to the diameter of the roller follower, and the strength and rigidity can be improved. (See Figure 2-8)

A driven sprocket 15 is press-fitted and fixed to a stepped shaft 11 _a provided at one end of the camshaft 11, and a pin 67, which is a projection for a cam phase detection sensor, is press-fitted and fixed to a boss portion. And the ignition timing is controlled by the output signal.
A plug 16 is press-fitted and fixed to the other end to close the hollow hole to form an oil passage and lubricate the camshaft bearing portion and the intake cam lobe. (See Figures 2-1 and 2)
A cam chain is wound and mounted between a driven sprocket 15 and a drive sprocket formed at one end of a crankshaft (hereinafter not shown) by a chain guide, a chain tensioner, a chain adjuster, or the like.

As shown in FIG. 2B, the rocker arm unit 20 is disposed near the center of the cylinder shaft when viewed from the direction parallel to the camshaft shaft on the side closer to the cylinder head mating surface (lower side) than the camshaft unit 10. the axial center of the shaft 27 has a cylinder head 1 and the lower cam shaft housing 2 _L mating surface.
By setting the rocker arm shaft axis center to the mating surface of the cylinder head and lower camshaft housing, the rocker arm shaft can be tightened without radial clearance by assembling the lower camshaft housing. The variation in the amount is reduced, and more accurate intake amount control can be performed on the intake side.
In addition, the cylinder head and the lower camshaft housing mating surface is used as the cylinder head cover mating surface for ease of processing, so the center of the rocker arm shaft near the cylinder head mating surface should be the cylinder head cover mating surface. Thus, the height of the cylinder head that requires a thick metal material can be reduced, and the cylinder head can be reduced in size and weight.

As shown in FIG. 2-4, the intake rocker arm 21 is rotatably supported by a pin 21-2 that is press-fitted and fixed to the tip portion via a needle bearing 21-3, and is a roller follower 21- that makes point contact with each cam. 4 and the cam follower arm 21 _a with the valve lift arm 21 _b to the stem top of intake valve unit 30 forward and backward the pressed valve via the adjusting screw 22, when viewed from a direction parallel to the camshaft axis, L-shaped Is a so-called roller rocker arm that is swingably supported by a rocker arm shaft 27 arranged in parallel to the camshaft shaft, and the center of the rocker arm shaft 27 is in the valve shaft direction within the approximate stroke range of the stem top surface. Is arranged. (See Figure 2-2)
In this embodiment, a rocker arm swinging shaft center is arranged near the center of the stroke on the top surface of the stem in order to minimize the amount of movement of the adjustment screw contact point with respect to the top surface of the valve stem in the direction perpendicular to the valve shaft and to suppress the force of turning the valve shaft. However, if the swing angle of the valve lift arm is small and the amount of movement of the contact point in the direction perpendicular to the valve shaft is small, or if the valve shaft has a large diameter and is strong against drooling such as a low-speed engine, it will swing for convenience of layout. The dynamic axis may be removed slightly outside the stroke range.

The valve lift arm portion 21 _b is formed in a comb shape from swing shaft portions 21 _cR and 21 _cL that are divided into left and right in the axial direction (the right valve lift arm portion 21 _bR and the left valve lift arm portion 21. two of _bL), provided adjusting screw bosses 21 _d in the front end portion in the vicinity of the valve stem shaft, connecting between the left and right bosses while connected by the arms 21 _e, at the pivot shaft portion ₂₁ cR, _{21 cL} between also the arms 21 _f The valve lift arm has a square shape. (See Fig. 2-3)
By connecting, the shape of the valve lift arm of the rocker arm becomes a square shape and the rigidity is improved. At the same time (the cylinder lift amount adjustment adjustment), all the valve system parts are assembled and lifted at one central position of the left and right adjustment screws. The amount can be measured, and the average value of the left and right valve lifts can be measured, so that the cylinder lift amount can be more accurately adjusted.
In addition, since the two rocker arm swinging shafts that lift the valve can have a long span, the fluttering can be suppressed, the fluctuation of the contact position between the 3D cam and the roller follower, and the fluttering of the left and right valve lifts can be reduced. Variations in lift amount can be reduced. In particular, on the intake side, the intake amount is controlled by the lift amount of the valve and the output is controlled. Therefore, it is essential to keep the variation in the lift amount small.
Further, by arranging one swinging shaft part of the exhaust swing arm between the divided swinging shaft parts, the total width of the swinging shaft part when the intake rocker arm and the exhaust swing arm are assembled is one of the exhaust swing arm. Since it is the sum of the width of the rocking shaft and the width of the outer side surface of the two rocking shafts of the intake rocker arm, shim adjustment can be performed without being affected by the pitch crossing between the rocking shafts. Fluctuation in the swing axis direction can be minimized.

The exhaust swing arm 21 _EX is, as shown in FIG. 2-3, the left of the valve lift arm portion 21 _EXb formed in a comb shape from the swinging shaft portions 21 _EXcR and 21 _EXcL that are divided into left and right in the axial direction. A needle bearing 21 _EX- 3 is _attached to a pin 21 _EX- 2 that is press-fitted and fixed in the middle between a swing shaft 21 _EXcL of the valve lift arm 21 _EXbL and an adjusting screw boss 21 _EXd provided near the tip of the valve stem shaft. Via a roller follower 21 _EX- 4 that is rotatably supported by the cam and is in line contact with each cam, and connects between both adjusting screw bosses and between both swinging shafts to form an arm shape in a square shape. A so-called roller swing arm pivotally supported on a rocker arm shaft 27 arranged in parallel to the camshaft shaft. It is disposed substantially within the stroke range of the exhaust valve stem top surface in the valve axis direction.
In all the embodiments, the roller follower 21 _EX- 4 is provided with an oil groove on the side surface, and oil mist from the outside is guided to the needle bearing 21 _EX- 3 and lubricated. (See Figure 2-8)
The right swing shaft portion 21 _EXcR of the exhaust swing arm 21 _EX is disposed between the swing shaft portions 21 _cR and 21 _cL of the intake rocker arm 21.
The camshaft unit and accelerator shaft unit are arranged on both sides of the exhaust valve stem axis as viewed from the direction parallel to the camshaft axis, and the box pressing wrench is used as an adjustment screw to adjust and tighten the box wrench type. Can be passed between the accelerator shaft and the camshaft, and the tappet clearance can be adjusted precisely and easily without reassembling the valve system parts before assembling all the valve system parts and mounting the head cover. Can be implemented efficiently.

The positions of the intake rocker arm 21 and the exhaust swing arm 21 _{EX in} the swing axis direction are fixed to the exhaust swing arm left swing shaft portion 21 _EXcL and the intake rocker arm swing shaft portion 21 _cR on both outer sides of the thrust washers 24 and on both outer sides thereof. shims 25, arranged circlip groove in the locked circlip 26 or rocker arm shaft 27 stepped portion 27 _a of the rocker arm shaft 27, the axial clearance of the swing shaft by adjusting the thickness of the horseshoe shims 25 While adjusting, the position of the intake rocker arm 21 in the swing axis direction is adjusted.
Horseshoe shims 25 a recess 25 _a provided in a part, the recess 25 _a in the omission of the fixed shim engaging piece 51 with bolts 51-2 to face the projecting end 51 _a of the locking piece 51, to prevent rotation ing.
Circlip 26 prevents at circlip phasing bosses 1-5 and locking pieces projecting end 51 _a provided in the cylinder head 1 and the lower cam shaft housing 2 _L cam lobe decided phase, contact between the accelerator fork guide bearings ing. Further, the locking piece 51 is positioned to prevent rotation at the time of bolt tightening at the steps 2 _LR -3, 2 _LC -3, and 2 _LL -3 provided in the lower camshaft housing 2 _L. (See Figures 2-3, 6, and 7)
The position of the rocking shaft in the rocking shaft direction is fixed by shimming both the rocking shaft outer surfaces of the intake rocker arm and the one-side rocking shaft of the exhaust swing arm without any gaps. Directional backlash can be minimized. Precise output control becomes possible by suppressing variations in the intake side lift.

Rocker arm shaft 27 is fastened pinching without radial clearance in a bearing hole formed in the cylinder head 1 and the lower camshaft housing 2 _L, accelerator shaft slide actuator unit stepped portion 27 provided in the vicinity of the housing 44-7 mounting 44 It is assembled to the cylinder head 1 and the lower cam shaft housing 2 _L without axial clearance in _a bevel-shaped circlip 28. (See Figures 2-1 to 4)
The rocker arm shaft 27 has a hollow structure, one end is plugged with a plug 27-2 to form a lubricating oil passage, and intake air is supplied by oil supplied through the lubricating oil passage formed in the cylinder head and the camshaft housing. The rocker shaft 21 _c of the rocker arm 21 and the rocker shaft 21 _EXc of the exhaust swing arm 21 _EX are lubricated, and needle bearings 21-3, 21 _EX- 3, cam crests, roller followers 21-4, 21 _EX -4 oil jet injection lubrication. (See Figures 2-3 and 4)

The intake valve unit 30 and the exhaust valve unit 30 _EX are basically the same as the first embodiment although the detailed specifications are different, and the description thereof is omitted.

The accelerator shaft unit 40 is basically the same as the first embodiment although the detailed specifications are different, and a description thereof will be omitted.

The valve operating apparatus according to the third embodiment is a specific example of claims 16 and 17, and in contrast to the second embodiment, both the camshaft unit and the rocker arm shaft unit are changed to the vicinity of the cylinder shaft, and both intake and exhaust are performed. The swing arm type rocker arm includes a camshaft unit 10, a swing arm unit 20, an intake valve unit 30, and an exhaust valve unit _30EX .
Moreover, the accelerator shaft unit 40 which slides a cam lobe according to an accelerator opening degree and a driving | running | working condition is included. (See Figures 3-1 to 5)
Of these, the description of the basically same one as in the second embodiment will be omitted or simplified as appropriate.
Since the camshaft and the rocker arm shaft are aligned in the cylinder axis direction, the cylinder head height is higher than in the second embodiment, but the cylinder head width in the intake and exhaust directions can be narrowed to a compact cylinder head, and the rocker arm shaft axis center Is the mating surface of the cylinder head and lower camshaft housing, the rocker arm shaft can be tightened without radial clearance by assembling the lower camshaft housing, and rocker arm flutter can be suppressed, and the variation in valve lift is reduced accordingly. Therefore, by adopting on the intake side, more accurate intake air amount control can be performed.
Also, the camshaft and rocker arm shaft are combined into one, so that the cost and weight can be reduced by reducing the number of iron parts, and the cylinder head and lower camshaft housing mating surface is the cylinder head cover mating surface for ease of processing. Therefore, by using the center of the rocker arm shaft near the cylinder head mating surface as the cylinder head cover mating surface, the cylinder head height requiring a thick metal material is reduced, and the cylinder in the suction and exhaust directions By reducing the head width, the cylinder head can be made smaller and lighter, and there is no obstructing valve part on the outside of the intake side V bank. The angle of the intake port relative to the cylinder axis can be reduced, and the intake efficiency and tumble flow can be reduced. Can be improved.

The camshaft unit 10 is disposed in the vicinity of the center of the cylinder shaft as viewed from the direction parallel to the camshaft axis, and is arranged on the exhaust valve unit 30 _EX side of the ignition plug hole (injector hole) 1 _IG substantially parallel to the valve stem axis. Together with the accelerator shaft unit 40 arranged on the opposite side, the axial center is the upper and lower camshaft housings 2 _U and 2 _L. (See FIG. 3-2).
The camshaft unit 10 is basically the same as the second embodiment although the detailed specifications are different, and a description thereof will be omitted.

As shown in FIG. 3-2, the swing arm unit 20 is disposed near the center of the cylinder shaft when viewed from the direction parallel to the camshaft shaft on the cylinder head mating surface side (lower side) with respect to the camshaft unit 10. the axial center of the shaft 27 has a cylinder head 1 and the lower cam shaft housing 2 _L mating surface.
By setting the rocker arm shaft axis center to the mating surface of the cylinder head and lower camshaft housing, the rocker arm shaft can be tightened without radial clearance by assembling the lower camshaft housing. The variation in the amount is reduced, and more accurate intake amount control can be performed on the intake side.
In addition, the cylinder head and the lower camshaft housing mating surface is used as the cylinder head cover mating surface for ease of processing, so the center of the rocker arm shaft near the cylinder head mating surface should be the cylinder head cover mating surface. Thus, the height of the cylinder head that requires a thick metal material can be reduced, and the cylinder head can be reduced in size and weight.

As shown in FIG. 3-10, the intake swing arm 21 is rotatably supported by a pin 21-2 that is press-fitted and fixed to the tip portion via a needle bearing 21-3, and is a roller follower 21 that makes point contact with each cam. a cam follower arm 21 _a with -4, the valve lift arm 21 _b to the stem top of intake valve unit 30 forward and backward the pressed valve via the adjusting screw 22, when viewed from a direction parallel to the camshaft axis, T-shaped Is a so-called roller swing arm that is swingably supported by a rocker arm shaft 27 disposed in parallel to the camshaft shaft. Arranged within the range. (See Fig. 3-2)

Valve lift arm 21 _b is the pivot shaft portion ₂₁ coupled with the arm arranged is divided into left and right axially cR, ₂₁ from one of the _{21 cL} of _cL, comb around the cam follower arm 21 _a swing axial position (The right valve lift arm portion 21 _bR and the left valve lift arm portion 21 _bL ), and an adjusting screw boss 21 _d is provided at the tip near the valve stem shaft. (See Figure 3-3)
Swing arm swinging shaft part that lifts the valve can have a long span, flutter is suppressed, fluctuation of contact position between 3D cam and roller follower and flutter of left and right valve lift can be reduced, and total lift of left and right valves The amount variation can be reduced.
In particular, on the intake side, the intake amount is controlled by the lift amount of the valve and the output is controlled. Therefore, it is essential to keep the variation in the lift amount small.
In addition, since the connecting part is close to the left and right pivot shafts, it is not possible to measure the lift amount at the center of the left and right adjustment screws during synchronization (adjustment of the lift amount between cylinders), and it is necessary to measure at both ends of both adjustment screws. However, the weight of the rocking tip is light and suitable for high speed engines.

As shown in FIG. 3-11, the exhaust swing arm 21 _EX is rotatably supported by a pin 21 _EX- 2 press-fitted and fixed to the tip portion via a needle bearing 21 _EX- 3, and makes line contact with each cam. A cam follower arm portion 21 _EXa having a roller follower 21 _EX- 4 and a valve lift arm portion 21 _EXb that _pushes the stem top portion of the exhaust valve unit 30 _EX through an adjusting screw 22 to advance and _{retract the} valve are _arranged in a direction parallel to the camshaft shaft. The so-called roller swing arm is integrally formed in a T-shape and is pivotally supported by a rocker arm shaft 27 arranged in parallel to the camshaft shaft. The center of the rocker arm shaft 27 is a stem in the valve shaft direction. It is arranged within the approximate stroke range of the top surface. (See Fig. 3-2)

The valve lift arm portion 21 _EXb is formed in a comb shape in the vicinity of the left and right valve shafts in the swing axis direction from the swing shaft portions 21 _EXcR and 21 _EXcL provided separately in the left and right directions in the axial direction (right valve lift arm The adjustment screw boss 21 _EXd is provided at the distal end near the valve stem shaft and is connected by an arm. The portion 21 _EXbR and the left valve lift arm 21 _EXbL ). (See Figure 3-3)
In this embodiment, the U-shaped arm is not connected between the left and right oscillating shafts by an arm. However, as in the fourth embodiment, a U-shaped arm that is connected by an arm and improves rigidity and strength may be used.
The right swing shaft portion 21 _EXcR of the exhaust swing arm 21 _EX is disposed between the swing shaft portions 21 _cR and 21 _cL of the intake swing arm 21.
By placing one rocking shaft part of another rocker arm between the divided rocking shaft parts, the total rocking shaft part width when two rocker arms are assembled is the width of one rocking shaft part of one rocker arm. Since the width of the outer side surface of the two rocking shafts of the other rocker arm is added, shimming can be performed without being affected by the pitch crossing between the rocking shafts. Can be minimized.

The fixing of the position of the intake rocker arm 21 and the exhaust swing arm 21 _{EX in} the swing axis direction is the same as in the second embodiment, and a description thereof will be omitted.

Rocker arm shaft 27 is fastened pinching without radial clearance in a bearing hole formed in the cylinder head 1 and the lower camshaft housing 2 _L, accelerator shaft slide actuator stepped portion 27a provided in the vicinity of the housing 44-7 mounting of the unit 44 It is assembled to the cylinder head 1 and the lower cam shaft housing 2 _L without axial clearance in the bevel shaped circlip 28. (See Figures 3-2, 4 and 5)
The rocker arm shaft 27 has a hollow structure, one end is plugged with a plug 27-2 to form a lubricating oil passage, and intake air is supplied by oil supplied through the lubricating oil passage formed in the cylinder head and the camshaft housing. The rocker shaft 21 _c of the rocker arm 21 and the rocker shaft 21 _EXc of the exhaust swing arm 21 _EX are lubricated, and needle bearings 21-3, 21 _EX- 3, cam crests, roller followers 21-4, 21 _EX -4 oil jet injection lubrication. (See Figure 3-3)

The intake valve unit 30 and the exhaust valve unit 30 _EX are basically the same as the first embodiment although the detailed specifications are different, and the description thereof is omitted.

The accelerator shaft unit 40 is basically the same as the first embodiment except that an idle gear 46, an idle gear shaft 47, and a needle bearing 48 with a cage are added. Are the same and will not be described. (See Figure 3-5)

The valve operating apparatus according to the fourth embodiment is a specific example of claims 18 to 21, and the third embodiment is a fork type in which the accelerator shaft unit and the camshaft unit are separated from the camshaft unit. The shaft unit is changed to a coaxial arrangement, and includes a camshaft unit 10, a swing arm unit 20, an intake valve unit 30, and an exhaust valve unit _30EX . Moreover, the accelerator shaft unit 40 which slides a cam lobe according to an accelerator opening degree and a driving | running | working condition is included. (See Figures 4-1 to 4)
Of these, the description of the basically same one as in the third embodiment will be omitted or simplified as appropriate.

The camshaft unit 10 has an accelerator shaft 41 disposed in the center hole, and the intake cam lobe 12 is fixed and slid to the accelerator shaft 41 via a key 41-2. Does not use a central bore as the oil passage, lubrication of the bearing portion has a structure for lubricating the bearings via an oil passage of the lower camshaft housing 2 _L the oil passage of the center hole of the rocker arm shaft. (See Fig. 4-4)

In the camshaft unit 10, the cam shaft 11 is rotatably supported by lower cam shaft housing 2 _L and upper cam shaft housing 2 _U. The camshaft 11 is provided with a key groove for slidingly guiding the key 41-2 of the accelerator shaft 41 in the axial direction at a phase corresponding to the ignition timing of each cylinder for each cylinder. The slide is guided while regulating the phase of the cam lobe with respect to the cam shaft of the intake cam lobe 12 fixed to the accelerator shaft 41.
The intake cam lobe 12 is a three-dimensional cam formed such that its height, working angle, and timing change continuously on the cam surface inclined in the camshaft axial direction. As the slide slides, the lift amount and working angle increase and the timing also changes. It is set to be able to let you. Therefore, as shown in FIG. 4-4, the cam crest on the sliding direction side becomes lower and gradually becomes higher as it becomes the opposite side in the sliding direction. On the opposite side of the sliding direction, the hooked pin 41-4 is inserted into the hole of the intake cam lobe 12 so as to sandwich the flange of the hooked pin 41-4 and the rising portion 41-2a of the key 41-2 at the end face of the intake cam lobe 12 without axial clearance. 4 is pressed in, the axial backlash of the intake cam lobe 12 with respect to the key 41-2 is minimized, and minute clearances are provided in the phase direction and the radial direction.
In the case where the accelerator shaft is arranged between the two camshafts as in the first embodiment, the sliding resistance of the cam lobe is applied to both sides of the fork. Because the force is weak, the resistance generated on the accelerator shaft bearing is small and it can be slid smoothly with low power. However, if the cam lobe slide on one camshaft is carried out with a fork fixed to the accelerator shaft, Since the sliding resistance of this becomes a moment as it is, the resistance force generated in the accelerator shaft bearing portion is large, and the power for sliding the cam lobe is increased. As a countermeasure, the generated moment can be greatly reduced by providing the accelerator shaft coaxially with the camshaft.
In addition, by making the cam lobe move slightly in the radial direction and phase direction with respect to the key, it is possible to absorb the alignment error of related parts and to slide the cam lobe smoothly on the camshaft. By fixing the movement to the minimum in the axial direction, the fluctuation of the lift amount can be suppressed to the minimum.
The exhaust cam 12 _EX is press-fitted and fixed to the side where the intake cam lobe 12 slides to the maximum lift side in a phase corresponding to the ignition timing of each cylinder. Further, the base circle diameter of the exhaust cam 12 _EX is set larger than the base circle diameter of the intake cam lobe 12. (See Figures 4-2 and 4)

The swing arm unit 20 extends the tip of the rocker arm shaft 27 from the axially fixed portion, and the details of the third embodiment and the details are the same except for the rotation restriction of the accelerator shaft slide actuator and the slide guide and idle gear bearing shaft. Although the difference is basically the same, the description is omitted. (See Fig. 4-4)
The slide guide shaft and idle gear shaft of the accelerator shaft slide actuator are not required.

The intake valve unit 30 and the exhaust valve unit 30 _EX are basically the same as the first embodiment although the detailed specifications are different, and the description thereof is omitted.

The accelerator shaft unit 40 is disposed in the center hole of the camshaft unit 10 and is supported so as to be slidable in the axial direction.
There is no valve system component above the adjusting screw 22 in the state before assembling all the valve system components and the head cover. Can be adjusted, and then synchronized with a horseshoe-shaped shim (adjustment of cylinder lift amount adjustment). (Adjustment of the lift amount) can be carried out precisely and efficiently.

In the accelerator shaft 41, a key 41-2 is inserted into a keyway carved with a phase corresponding to the ignition timing of each cylinder for each cylinder, and is fixed by a bolt 41-3. The key 41-2 is guided by the key groove in which the intake cam lobe 12 fixed to the accelerator shaft 41 via the key 41-2 slides and guides the key 41-2 provided in the camshaft 11 in the axial direction. Slide while the phase is regulated.
Further, a bearing 41-5 is inserted into a stepped shaft portion at one end of the accelerator shaft 41, and an inner race is fixed by a bevel-shaped circlip 41-6 without backlash in the axial direction. A joint bracket 44-2 for press-fitting and fixing the outer race of the bearing 41-5 to the male screw shaft 44-1 of the accelerator shaft slide actuator unit 44 and guiding the slide while restricting the rotation of the male screw shaft 44-1 is press-fitted and fixed. ing. The joint bracket 44-2 is provided with a groove for engaging the tip of the detection arm 73 of the accelerator shaft slide sensor 72. The amount of slide of the accelerator shaft 41 is detected by the phase change of the detection arm 73 to control the accelerator motor 45. ing. (See Figures 4-4 and 9)

The accelerator shaft slide actuator unit 44 is fixed to the cylinder head 1 by a housing 44-7, and a driven gear 44-4 is fixed to a female screw boss portion 44-3 by a key 44-5 and a circlip 44-6. The female screw boss 44-3 is rotatably supported by bearings 44-8a and 44-8b. The bearing 44-8a is press-fitted into the female screw boss 44-3 and a stepped portion of the housing 44-7. And a bevel-shaped circlip 44-9, which is fixed to the housing 44-7 without any axial clearance, and by using a four-point contact bearing, the axial backlash of the female screw boss 44-3 is minimized. Yes. In this embodiment, a ball screw type is used to reduce mechanical loss, but a trapezoidal screw may be adopted.
A drive gear 45-2 fixed to the output shaft of the accelerator motor 45 fixed to the cylinder head 1 by a spline and a circlip 45-3 is rotatably supported by a needle bearing 48 with a cage on the rocker arm shaft 27 axis. The rotation of the output shaft of the accelerator motor 45 that meshes with the driven gear 44-4 and corresponds to the accelerator opening degree and the traveling state is converted into the sliding movement of the accelerator shaft 41, that is, the intake cam lobe 12, through the idle gear 46. (See Figures 4-1 and 4)

The valve operating apparatus according to the fifth embodiment is a specific example of claims 22 to 25, and the exhaust cam of the fourth embodiment is changed to a forced opening / closing cam. An intake valve unit 30 and an exhaust valve unit 30 _EX are included. Moreover, the accelerator shaft unit 40 which slides a cam lobe according to an accelerator opening degree and a driving | running | working condition is included. (See Figures 5-1 to 4)
Of these, the description of the basically same as the fourth embodiment will be omitted or simplified as appropriate, including the sectional view.
By forcibly opening and closing the exhaust side, tappet clearance adjustment can be performed without reassembling the valve system parts until all the valve system parts are assembled and the head cover is assembled after the cylinder head is assembled to the cylinder. And it is impossible to synchronize (lift adjustment between cylinders), but after adjusting the tappet clearance on the exhaust side with shim tone, until the state before assembling all valve system parts and assembling the head cover, Intake side tappet clearance adjustment and tuning (inter-cylinder lift adjustment) can be performed precisely and efficiently without re-disassembling the valve system parts.

Since the camshaft unit 10 is basically the same as the fourth embodiment except that the exhaust cam is changed to a forced opening / closing cam, only the exhaust cam will be described. The exhaust cam has a base circle diameter larger than that of the second to fourth embodiments, and is arranged so as to overlap the stroke range of the intake cam lobe 12. When viewed from a direction parallel to the camshaft shaft, the exhaust cam hole (injector hole) 1 _IG side A cam that contacts the roller follower 21 _EX- 4 (exhaust valve opening cam 12 _{EXO in the} present embodiment) is moved away from the intake cam lobe 12 to an ignition plug hole (injector hole) 1 on the roller follower 21 _EX- 4 on the side without the _IG. A cam (exhaust valve closing cam 12 _EXC ) in contact with the intake cam lobe 12 is arranged on the intake cam lobe 12 side, and the phases of the intake cam crest and the exhaust open cam crest that overlap the exhaust cam are substantially matched to overlap the intake cam lobe stroke. The range is the thickness that can secure the strength from the cam surface, and the inner side is thinned and slides to the maximum lift side to the thinned portion Facing the cam mountain of the intake cam lobe. (See Figures 5-2, 4, and 7)
The stroke of the intake cam lobe can be increased, and a forced open / close cam can be used on the exhaust side. When the intake cam lobe is slid to the maximum lift side, strength can be secured from the cam surface of the exhaust cam (open cam for the forced open / close cam). By increasing the cam cam of the intake cam lobe over the thickened part, the increase in the base circle diameter of the exhaust cam can be minimized, and higher rotation and lower mechanical loss can be achieved. In addition, if the exhaust side is forced to open and close, the opening area can be expanded if the working angle is the same, and the working angle can be reduced if the effective area (the product of the opening area and the flow coefficient) is made equivalent. , Increase output, fuel efficiency, freedom to choose exhaust gas reduction measures.
(In FIG. 5-10, the solid line of the exhaust lift curve is an example when a valve return spring is attached, and the broken line is an example of forced opening and closing.)
The clearance between the valve lift arm on the spark plug hole (injector hole) side and the spark plug hole tube (injector hole tube) is easy to secure, and the valve lift arm on the side without the spark plug hole (injector hole) is connected to the rocker arm shaft shaft. Because it can be arranged in a position that overlaps the spark plug hole tube (injector hole tube) in the direction, the exhaust forced opening / closing cam can be adopted even in a small engine with a narrow cylinder pitch.

The swing arm unit 20 changes the exhaust side corresponding to the forced opening and closing with respect to the fourth embodiment, and the description of the relationship between the intake side and the rocker arm shaft is omitted as in the fourth embodiment.
As shown in FIGS. 5-3 and 6, the exhaust swing arm 21 _EX is rotatably supported by a pin 21 _EX- 2 press-fitted and fixed to the tip portion via a needle bearing 21 _EX- 3, and makes line contact with each cam. the opening cam follower arm _{21 EXaO} and closing cam follower arm _{21 EXaC} having roller followers ₂₁ EX -4 to, when viewed from a direction parallel to the cam shaft axis, with integrally formed in a V shape sandwiching the cam, the exhaust valve The valve lift arm 21 _EXb that engages with a shim in the upper and lower _cages of the retainer portion of the unit 30 _EX to lift the valve is also integrated with the rocker arm shaft 27 that is arranged in parallel to the camshaft shaft. The axis of the rocker arm shaft 27 is supported by a substantially stroke range at the center between the upper and lower contact surfaces of the retainer collar in the valve axis direction. It is disposed within. (See Fig. 5-2)

The valve lift arm portion 21 _EXb is formed in two comb shapes near the left and right valve shafts in the axial direction of the swing shaft portion 21 _EXc. The valve lift arm portion 21 _EXb is further divided into two branches near the tip portion retainer. The upper and lower shims are engaged with each other and are connected by a connecting arm 21 _EXe . The contact point with the shim disposed between the flange portion and the shim portion is on a line substantially passing through the valve shaft and parallel to the swing shaft portion 21 _EXc . The swing shaft portion 21 _EXc is provided in the axial direction so as to be divided in the vicinity of the left and right valve lift arm portions, and between the left and right swing shaft portions 21 _EXcR and 21 _EXcL , the left swing shaft portion 21 _{cL of the} intake swing arm 21. There is disposed, is disposed right swing shank 21 _cR of the intake swing arm 21 to the right portion of the right swing shaft portion 21 _EXcR, it is swingably supported by the rocker arm shaft 27. The left and right oscillating shaft portions 21 _EXcR and 21 _EXcL are connected by a connecting arm 21 _EXf, and the valve lift arm portion 21 _EXb , the oscillating shaft portion 21 _EXc , and the connecting arms 21 _EXe and 21 _{EXf have a} square shape. A spark plug hole (injector hole) 1 _IG is disposed substantially parallel to the exhaust intake valve unit 30 _EX . (See Figures 5-3 and 6)

Since the intake valve unit 30 is the same as in the fourth embodiment, the description thereof is omitted.
As shown in FIG. 5B, the exhaust valve unit 30 _EX includes two exhaust valves 31 _{EX in} which the exhaust valve stem 31 _EXa is guided by the exhaust valve guide 1-3 _EX .
When the exhaust air valve 31 _EX is lifted, the combustion gas in the cylinder is discharged through an exhaust pipe (not shown) through the exhaust port 1 _EX .

In the embodiment shown in FIG. 5-2, a conical split cotter generally used in a valve operating device with a valve return spring is used as a locking piece (33 _EX ), and the top of each exhaust valve stem 31 _EXa is used. A cotter 33 _EX locked to a cotter groove in the vicinity has a tapered portion that engages with the cotter on the lower inner side of the cylinder portion, a female screw on the upper inner side, and a lower retainer 34 _EX provided with a flange on the lower outer side. by tightening the 35 _EX is fixed to the exhaust valve _{31 EX,} forms a retainer portion with upper and lower flange by tightening the flanged nut _{36 EX} set screw _{35 EX.}
Since the locking piece (33 _EX ) only needs to be fixed in the axial direction of the lower retainer, a ring with a circular cross section or a semicircular locking piece with a circular cross section may be used.
The shim can be inserted between the cage and the retainer contact part of the valve lift swing arm part, and it is made difficult to loosen by tightening the male screw with two nuts.
A flat washer shim 37 _EX is placed between the tip of the valve lift arm 21 _EXb and the upper and lower flanges of the retainer, and the thickness of the shim 37 _EX is adjusted to adjust the alignment error and ensure proper clearance. Yes. (See Fig. 5-2)
Since there is no function of absorbing a flat washer-like shim 37 _EX in the angle error, so that the contact between the valve lift arm 21 _EXB tip not to end, the crowning is attached to the valve lift arm 21 _EXB tip ing. However, even if the angle accuracy of the contact surface with the end of the valve lift arm of the retainer's upper and lower collars is improved, it will hit only at one of the two contact parts, and there is a high probability that the valve will lift and lift. Other measures may be required for small engines with a thin stem shaft and high-speed engines.

FIG. 5-9 shows an angle error absorbing shim that absorbs an angle error, prevents the valve from being lifted and lifted, and corresponds to a small engine with a thin valve stem shaft and a high-speed engine. Shim 37 retainer flange side contact surface 37 _EXa of _EX contact the mound a substantially perpendicular linear to the rocker arm pivot shaft with respect to the contact line between the shim 37 _EX and valve lift arm 21 _EXB shim contacting portion of the tip By providing a stopper 37 _EXb that is substantially orthogonal as viewed from the valve axial direction and that maintains the orthogonality, the angle error in the forward direction is absorbed, and even if there is no crowning at the tip of the valve lift arm 21 _EXb , the shim 37 is always provided. Contact between the _EX and the shim contact portion at the tip of the valve lift arm 21 _EXb is kept in a linear shape, reducing contact Hertz stress and reducing wear.
The lower retainer 34 _EX and the flange nut 36 _EX are generally made of steel. However, when titanium or aluminum is used to reduce mechanical loss and increase the rotation speed, the shim 37 _EX and the lower retainer 34 are used. _A steel washer is added between the _EX and the hooked nut 36 _EX so that it can withstand contact Hertz stress with the _chevron of the retainer _hook side contact surface 37 _EXa .

The flange lower surface of the lower retainer _{34 EX} is provided a cylindrical guide _{34 EXa,} cylindrical guide _{34 EXa} between the exhaust valve spring seat _{38 EX} of the exhaust valve guide _{1-3 EX} press-fitting portion upper cylinder head 1 exhaust valve spring _{39 EX} guided is housed by and exhaust valve guide _{1-3 EX.} The exhaust valve spring 39 _EX is a coil spring and has a weak spring load having only a sealing function between the valve umbrella and the valve seat. (See Fig. 5-2)

The sixth embodiment is a specific example of claim 26, which relates to the cross-sectional shape of the roller follower outer periphery of the roller rocker arm (swing arm) that makes point contact with the three-dimensional cam, and is the first countermeasure against fretting corrosion that occurs when there is no lift. It is necessary to apply to all the valve gears of the fifth embodiment.
In the roller follower of the sixth embodiment, the maximum outer diameter portion is set to the maximum R, R is set to the maximum R that can absorb the alignment error between the camshaft unit and the rocker arm unit, and in the axial direction in which the cam peak height and the working angle increase. R has a barrel shape with a reduced outer diameter by a quadratic curve. (See Figure 6-1)
In this embodiment, the drop amount d from the maximum outer diameter at both ends A ′ and B ′ of the maximum R portion (cam base circle cylindrical surface contact portion when there is no lift) width L is calculated by the following formula. The center C of the maximum R section width L is the maximum outer diameter, the R connecting the points A ′, B ′ and C is set to the maximum R, and the center of the roller follower shaft at the point B ′ is the center of the maximum outer diameter. Is a shape connected by a quadratic curve toward the contact point D (the contact end during lift) on the cam mountain maximum inclination angle α on R ′. (Solid line in Fig. 6-1)
d = (Axial tilt of the base circle cylindrical surface with respect to the shaft hole of the cam lobe + parallel error including bending of the cam shaft and the rocker arm shaft + an axial tilt of the roller follower with respect to the swing shaft hole of the roller rocker arm (swing arm)) A value obtained by converting the maximum value into a width L, for example, if the total alignment error in () is 100 mm span and 0.1 mm and the maximum R portion width L is 2 mm, d is 0.002 mm and the maximum R is 250 mm.
By adopting a roller follower that makes point contact with the three-dimensional cam, if the contact R when there is no lift is small, fretting corrosion wear due to slight vibration hitting the cam and the roller follower contact portion occurs due to clearance, and due to shape change There is a problem that increases noise due to fluctuations in lift amount and increase in tappet clearance. As a countermeasure, a cylindrical surface is connected to the side of the spherical outer surface as shown by the two-dot chain line in Fig. 6-1. Patent Document 9 discloses that the roller follower is brought into line contact to lower the surface pressure and prevent fretting corrosion wear. For the thing, the cam and the roller follower cylindrical surface are pressed by the left and right valve spring reaction force on both ends of the arm with a balance function. Therefore, the force that moves the cam and the roller follower cylindrical surface works and absorbs the alignment error, so the effect of providing the cylindrical surface can be obtained. Therefore, contact is made only at both ends A and B of the cylindrical surface in FIG. 6A, resulting in point contact and an increased amount of wear. In particular, wear at point B causes fluctuations in the valve lift amount, so a countermeasure is required. (Each bearing clearance and needle bearing crowning absorbs alignment errors, but the effect is small.) By adopting this plan, alignment errors can be absorbed, but they are all-point contact and not line contact when there is no lift.
However, since the surface pressure can be made close to line contact with a large R, fretting corrosion wear when there is no lift can be prevented, and the change in curvature at the B point can be reduced, so that wear at the B point can also be prevented.

Hereinafter, the embodiment diagram will be described in the cylinder head block portion in which the valve operating apparatus is accommodated, and the cam chain related to driving the valve operating apparatus will be omitted in the illustration and description. The engine unit described in the present embodiment is a parallel two-cylinder, and each cylinder has two valves on each of the intake side (IN) and the exhaust side (EX). However, the present invention is not limited to two cylinders, and can be applied to a single cylinder and a multi-cylinder internal combustion engine having three or more cylinders.
In each drawing, some drawings are omitted as necessary. About 2nd to 5th embodiment, the same code | symbol is used for the same or corresponding member as 1st embodiment.

It is a top view (sectional view which meets an AA line of Drawing 1-2) which shows a valve gear concerning a first embodiment. It is sectional drawing which follows the BB line of FIGS. 1-1. It is sectional drawing which follows the CC line of FIGS. 1-2. It is sectional drawing which follows the DD line | wire of FIGS. 1-2. It is sectional drawing which follows the EE line of FIGS. 1-2. It is sectional drawing which follows the FF line of FIGS. 1-2. It is sectional drawing which follows the GG line of FIGS. 1-1. It is sectional drawing which follows the HH line of FIGS. 1-1. It is an exhaust port sectional view (water passage diagram). (J-J cross section of Fig. 1-2) It is a rocker arm rocking | fluctuation shaft position adjustment explanatory drawing by the spacer with an inclination cam surface.

It is a top view (sectional view which meets an AA line of Drawing 2-2) showing a valve gear concerning a second embodiment. It is sectional drawing which follows the BB line of FIGS. It is sectional drawing which follows the CC line of FIG. It is sectional drawing which follows the DD line | wire of FIGS. It is sectional drawing which follows the EE line of FIGS. It is sectional drawing which follows the FF line | wire of FIGS. It is sectional drawing which follows the GG line of FIGS. It is sectional drawing which follows the HH line of FIGS. It is an exhaust port sectional view (water passage diagram). (J-J cross section of Fig. 2-2)

It is a top view (sectional view which meets an AA line of Drawing 3-2) showing a valve gear concerning a third embodiment. It is sectional drawing which follows the BB line of FIGS. It is sectional drawing which follows the CC line of FIGS. 3-2. It is sectional drawing which follows the DD line | wire of FIGS. 3-2. It is sectional drawing which follows the EE line | wire of FIGS. 3-2. It is sectional drawing which follows the FF line of FIGS. 3-3. It is sectional drawing which follows the GG line of FIGS. 3-6. It is sectional drawing which follows the HH line | wire of FIGS. It is sectional drawing which follows the JJ line of FIGS. 3-8. It is sectional drawing which follows the KK line | wire of FIGS. 3-2. It is sectional drawing which follows the LL line | wire of FIGS. 3-2.

It is a top view (sectional view which meets an AA line of Drawing 4-2) which shows a valve gear concerning a fourth embodiment. It is sectional drawing which follows the BB line of FIGS. It is sectional drawing which follows the CC line of FIGS. 4-2. It is sectional drawing which follows the DD line | wire of FIGS. 4-2. It is sectional drawing which follows the EE line of FIGS. 4-2. It is sectional drawing which follows the FF line of FIGS. 4-2. It is sectional drawing which follows the GG line of FIGS. 4-3. It is sectional drawing which follows the HH line | wire of FIGS. 4-3. It is sectional drawing which follows the JJ line of FIGS. It is sectional drawing which follows the KK line | wire of FIGS.

It is a top view (sectional view which meets an AA line of Drawing 5-2) showing a valve gear concerning a 5th embodiment. It is sectional drawing which follows the BB line of FIGS. It is sectional drawing which follows the CC line of FIG. It is sectional drawing which follows the DD line | wire of FIG. It is sectional drawing which follows the EE line | wire of FIG. It is sectional drawing which follows the FF line | wire of FIG. It is sectional drawing which follows the GG line of FIGS. It is sectional drawing which follows the HH line of FIGS. It is a detailed view of an angle error absorption shim. It is a valve lift curve figure.

It is sectional drawing (roller follower part enlarged view of FIGS. 1-3) which shows the roller follower which concerns on 6th embodiment.

1 Cylinder head 1 _IN intake port 1 _EX exhaust port
1 _IG ignition plug hole (injector hole)
1-2 Intake Valve Seat 1-2 _EX Exhaust Valve Seat 1-3 Intake Valve Guide 1-3 _EX Exhaust Valve Guide 1-4 Dust Hole Plug 1-5 Circlip Phase Determination Boss 2 Camshaft Housing 2 _L Lower Camshaft Housing 2 _LR lower right camshaft housing
2 _LC lower middle camshaft housing
2 _LL lower left camshaft housing
2 _LR- 2 circlip phasing boss
2 _LC- 2 circlip phasing boss
2 _LR -3 steps
2 _LC -3 steps
2 _LL- 3 level difference 2 _U upper camshaft housing 2 _UR upper right camshaft housing
2 _UC upper middle camshaft housing
2 _UL upper left camshaft housing 2-1 Bolt 2-2 Knock pin 3 Cylinder head cover 3-2 Cylinder head cover gasket 3-3 Cylinder head cover bolt 3-4 Cylinder head cover seal washer 4 Accelerator shaft unit cap 4-1 O-ring 10 Intake cam shaft unit 11 intake camshaft 11 _a stepped shaft _{10 EX} exhaust camshaft unit 11 _EX the exhaust camshaft 11 _EXa stepped shaft 12 intake cam lobe 12 _EX exhaust cam (lobe) _{12 EXO} exhaust valve opening cams
12 _EXC exhaust valve closing cam 13 Accelerator fork guide bearing 14 Cam lobe slide guide key 15 Driven sprocket 16 Plug 17 Drive gear 18 Washer 19 Bolt 20 (Intake) Rocker arm unit (swing arm unit)
21 Intake rocker arm 21 _a Cam follower arm
21 _b Valve lift arm
21 _bR right valve lift arm
21 _bL left valve lift arm
21 _c swing shaft
21 _cR right swing shaft
21 _cL left swing shaft
21 _d adjusting screw boss
21 _e Connecting arm
21 _f connecting arm 21-2 pin 21-3 needle bearing 21-4 roller follower 20 _EX exhaust swing arm unit 21 _EX exhaust swing arm 21 _EXa cam follower arm
21 _EXaO valve opening cam follower arm
21 _EXaC valve closing cam follower arm
21 _EXb valve lift arm
21 _EXbR right valve lift arm
21 _EXbL left valve lift arm
21 _EXc swing shaft
21 _EXcR right _swing shaft
21 _EXcL left _swing shaft
21 _EXd Adjust Screw Bos
21 _EXE connecting arm
21 _EXf connecting arm 21 _EX- 2 pin 21 _EX- 3 needle bearing 21 _EX- 4 roller follower 22 adjusting screw 23 nut 24 thrust washer (spacer) 24 _a inclined cam
24 _b Serration 24 _EX thrust washer combined shim 25 Horseshoe shim (spacer) 25 _a recess (inclined cam)
25 _b Serration 26 Circlip 27 Rocker arm shaft 27 _a Stepped part
27 _IN intake rocker arm shaft
27 _INa stepped part
27 _EX exhaust rocker arm shaft 27-2 plug 28 bevel type circlip 29 stopper bolt 30 intake valve unit 31 intake valve 31 _a intake valve stem 30 _EX exhaust valve unit 31 _EX exhaust valve 31 _EXa exhaust valve stem 32 valve stem seal 33 cotter 33 _EX locking piece (cotter)
34 _Retainer 34 _a Cylindrical guide 34 _EX lower retainer 34 _EXa cylindrical guide 35 _EX set screw 36 _EX flange nut 37 _EX shim 37 _EXa retainer side contact surface
37 _EXb stopper 38 Valve spring seat 38 _a Cylindrical guide 38 _EX exhaust valve spring seat 39 Valve spring 39 _EX exhaust valve spring 40 Accelerator shaft unit 41 Accelerator shaft 41-2 Key 41-2 _a Rising part 41-3 Bolt 41-4 41-5 bearing pin 41-6 bevel circlip 42 accelerator fork 42 _R right accelerator fork
42 _L Left Accelerator Fork 43 Joint Bracket 43-2 Bolt 43-3 Nut 44 Accelerator Shaft Slide Actuator Unit 44-1 Male Screw Shaft 44-2 Joint Bracket 44-3 Female Thread Boss 44-3 _a Spacer 44-4 Driven Gear 44- 5 Key 44-6 Circlip 44-7 Housing 44-7U Upper housing
44-7L Lower housing
44-7K dowel pin
44-7B bolt 44-8 _a bearing 44-8 _b bearing 44-9 bevel type circlip 45 accelerator motor 45-2 drive gear 45-3 circlip 45-4 bolt 45-5 O-ring 46 idle gear 47 idle gear shaft 48 Needle bearing with cage 49 Thrust washer 51 _Locking piece 51a Tip protrusion 51-2 Bolt 61 First driven gear 61 _EXa boss 62 Second driven gear 63 Key 64 Washer 65 Circlip 66 Spring 67 Pin 71 Phase sensor unit 72 Accelerator shaft Slide sensor 72-1 Bolt 72-2 O-ring 73 Detection arm 81 Spark plug hole tube (Injector hole tube)
82 O-ring T Spacer outer surface dimension t Spacer outer surface dimension change

Claims (26)

The cam lobe is designed so that its height, working angle, and timing change continuously on the cam surface inclined in the camshaft axial direction, and rotates in unison with the camshaft and is relatively movable in the axial direction. Roller rocker arm (swing arm) that pushes and retracts the valve when it is pressed, and by sliding the cam lobe in the camshaft axis direction according to the accelerator opening and travel conditions, the valve lift, working angle, and timing are continuously variable In a valve device that is variably controlled, the lift height is adjusted by changing the position of the roller rocker arm (swing arm) in the swing axis direction. The valve operating apparatus according to claim 1, wherein the position of the roller rocker arm (swing arm) in the swing axis direction is adjusted by a shim. The valve gear according to claim 1 or 2, wherein the shim has a horseshoe shape, and the locking piece prevents the shim from coming off and rotating from the rocker arm shaft. Adjusting the position of the roller rocker arm (swing arm) in the direction of the swing axis is provided on the mating surface of each other by rotating a pair of spacers connected in the axial direction of the rocker arm shaft relatively around the axis of the rocker arm shaft. 2. The valve operating apparatus according to claim 1, wherein the axial dimension of the rocker arm shaft is changed by the inclined cam, and the axial dimension is fixed by fixing the phase of the spacers with the locking piece. 2. The motion according to claim 1, wherein the position of the roller rocker arm (swing arm) in the swing axis direction is fixed by the rocker arm shaft, and the rocker arm shaft is fixed in the axial direction in the vicinity of a fixed portion of the accelerator shaft slide actuator unit to the cylinder head. Valve device. The cam lobe is designed so that its height, working angle, and timing change continuously on the cam surface inclined in the camshaft axial direction, and rotates in unison with the camshaft and is relatively movable in the axial direction. Roller rocker arm (swing arm) that pushes and retracts the valve when it is pressed, and by sliding the cam lobe in the camshaft axis direction according to the accelerator opening and travel conditions, the valve lift, working angle, and timing are continuously variable In a valve system that is variably controlled, the intake and exhaust camshafts are arranged on both sides of the valve stem axis of one of the valves when viewed from the camshaft axis direction, and each rocker arm shaft is on the cylinder head mating surface side with respect to the camshaft. A valve gear arranged on the (lower side). The intake and exhaust camshafts are disposed on both sides of the exhaust valve stem axis when viewed from the camshaft axial direction, and an ignition plug hole (injector hole) is disposed substantially parallel to the intake valve stem shaft on the intake valve side. The valve gear described in 1. 8. The valve operating device according to claim 6, wherein the shaft center of the camshaft outside the suction and exhaust valve shaft V bank and the shaft center of the rocker arm shaft inside the V bank are the mating surfaces of the cylinder head and the lower camshaft housing. 17. The valve operating apparatus according to claim 6, 7, 8, 13, or 16, wherein the axial center of the accelerator shaft and the axial center of the cam shaft in the V bank are the mating surfaces of the lower cam shaft housing and the upper cam shaft housing. 8. The valve operating apparatus according to claim 6, wherein the left and right valve lift arm portions of the intake roller rocker arm are connected near the tip. The cam lobe is designed so that its height, working angle, and timing change continuously on the cam surface inclined in the camshaft axial direction, and rotates in unison with the camshaft and is relatively movable in the axial direction. Roller rocker arm (swing arm) that pushes the valve back and forth is pushed, and the cam lobe slides in the camshaft axial direction according to the accelerator opening and travel conditions, so that the intake valve lift amount, working angle, and timing are stepless Continuously variable control, the exhaust valve is in contact with the flat cam surface and pressed, and it is a roller swing arm that moves the valve forward and backward. In the valve operating device, the intake and exhaust cams are provided on the same camshaft, and the intake cam lobe has the maximum lift. A valve operating device with an exhaust cam on the side that slides to the side. The valve gear according to claim 11, wherein a base circle diameter of the exhaust cam is larger than a base circle diameter of the intake cam lobe. A camshaft is provided in the suction and exhaust valve V bank near one of the valves, and a rocker arm shaft is used as a single unit, and the camshaft is positioned near the center of the cylinder shaft when viewed from the camshaft axial direction on the cylinder head mating surface side. The valve on the camshaft side is advanced and retracted by a swing arm having a roller follower between the pressing part and the swinging shaft part, and the other valve is moved by a rocker arm having a swinging shaft part between the pressing part and the roller follower. The valve gear according to claim 11, wherein the rocker arm shaft axis center is a mating surface of the cylinder head and the lower camshaft housing. The valve operating apparatus according to claim 13, wherein the valve pressing portion is an adjusting screw, and the accelerator shaft is disposed on the opposite side of the camshaft with respect to the valve stem axis. In the intake and exhaust rocker arms, the swinging shaft part is divided into left and right in the axial direction, the roller follower arm part is arranged on one side of the divided swinging shaft part, and the vicinity of the tip of the left and right valve lift arm parts is connected. 14. The valve operating device according to claim 13, wherein one rocking shaft portion of the other rocker arm is disposed between the divided rocking shaft portions. The camshaft is located near the center of the cylinder shaft as viewed from the camshaft axis direction, the rocker arm shaft is one, and the camshaft is located near the center of the cylinder axis as viewed from the camshaft axis direction on the cylinder head mating surface side. 12. The valve operating valve according to claim 11, wherein both valves are advanced and retracted by a swing arm having a roller follower between the pressing portion and the swinging shaft portion, and the center of the rocker arm shaft shaft is used as a mating surface of the cylinder head and the lower camshaft housing. apparatus. In the intake and exhaust swing arms, the swinging shaft part is divided into left and right in the axial direction, the roller follower arm part is arranged on one side of the divided swinging shaft part, and the vicinity of the left and right swinging shaft part of the intake swing arm is arranged. 19. The valve operating device according to claim 16, wherein one swinging shaft portion of the exhaust swing arm is disposed between the swing shaft portions that are connected and divided. The cam lobe is designed so that its height, working angle, and timing change continuously on the cam surface inclined in the camshaft axial direction, and rotates in unison with the camshaft and is relatively movable in the axial direction. Roller rocker arm (swing arm) that pushes and retracts the valve when it is pressed, and by sliding the cam lobe in the camshaft axis direction according to the accelerator opening and travel conditions, the valve lift, working angle, and timing are continuously variable In a variable valve control system, an accelerator shaft for sliding the cam lobe is provided coaxially with the cam shaft, the cam lobe is fixed to a key fixed to the accelerator shaft, and the key and cam lobe are separated by a long groove opened in the axial direction of the cam shaft. Cam shaft axial slide of key and cam lobe while restricting rotation with respect to cam shaft Guide and the valve operating system. Claims: The cam lobe has a key that is securely fixed so that it does not move relative to the accelerator shaft, and the cam lobe is provided with a clearance that can move slightly in the radial direction and phase direction, and is fixed so that the movement is minimized in the key axis direction. The valve gear described in 18. 19. The valve operating apparatus according to claim 18, wherein a rocker arm shaft is shared as a shaft for guiding the slide while regulating the rotation of the shaft of the accelerator shaft slide actuator. 19. The valve gear according to claim 18, wherein the rocker arm shaft is shared as a bearing shaft of an idle gear of a drive gear train of an accelerator shaft slide actuator. The cam lobe is designed so that its height, working angle, and timing change continuously on the cam surface inclined in the camshaft axial direction, and rotates in unison with the camshaft and is relatively movable in the axial direction. Roller rocker arm (swing arm) that pushes the valve back and forth is pushed, and the cam lobe slides in the camshaft axial direction according to the accelerator opening and travel conditions, so that the intake valve lift amount, working angle, and timing are stepless Continuously variable control, the exhaust valve is in contact with the flat cam surface and pressed, and it is a roller swing arm that moves the valve forward and backward. In the valve operating device, the intake and exhaust cams are provided on the same camshaft, and the intake cam lobe has the maximum lift. A valve operating device in which an exhaust cam is arranged on the side that slides to the side, overlapping the stroke range of the intake cam lobe. 23. The valve gear according to claim 22, wherein the phases of the intake cam crest and the exhaust cam crest (open cam crest in the case of a forced opening / closing cam) in a portion overlapping the exhaust cam are approximately matched. The valve gear according to claim 22, wherein the exhaust cam is forcibly opened and closed. When viewed from the direction parallel to the camshaft shaft, the cam that contacts the roller follower on the ignition plug hole (injector hole) side is moved away from the intake cam lobe, and the cam that contacts the roller follower on the side without the ignition plug hole (injector hole) is sucked. The valve gear according to claim 24, arranged close to the cam lobe. The cam lobe is designed so that its height, working angle, and timing change continuously on the cam surface inclined in the camshaft axial direction, and rotates in unison with the camshaft and is relatively movable in the axial direction. Roller rocker arm (swing arm) that pushes and retracts the valve when it is pressed, and by sliding the cam lobe in the camshaft axis direction according to the accelerator opening and travel conditions, the valve lift, working angle, and timing are continuously variable In the variable valve control device, the outer peripheral cross-sectional shape of the roller follower that makes point contact with the cam surface is set to the maximum outer diameter R, and R is set to the maximum R that can absorb the alignment error between the camshaft unit and the rocker arm unit. A valve operating device having a barrel shape in which the outer diameter is reduced by a quadratic curve in the axial direction in which the cam peak height and the working angle increase.

Images