JP2014020358A - Inner shaft slide-type cam phase variable valve gear - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress response delay to approximately zero, as a low lift region intake time area is narrow in comparison with an output, and deviation of overlap has a great influence on an exhaust gas, in a case when VVL is applied at an intake side and a phase is variable at an exhaust side.SOLUTION: In the cam phase variable valve gear in which a phase of a part or all of cams coaxially disposed in parallel with each other is variable, a cam shaft is a double shaft, an inner shaft or an outer shaft, or the phase variable-cam is provided with a cam groove, the phase-variable cam is journaled to the outer shaft in a state of being fixed in the axial direction and rotatable in the phase direction, and the phase of the cam can be changed by a pin facing the cam groove by sliding the inner shaft in the cam shaft direction.

Description

The present invention relates to an internal combustion engine in a two-wheeled vehicle or an automobile in which the phase of some or all of the cams arranged in parallel on the same axis is variable. The camshaft is a double shaft, and the inner shaft or the outer shaft. Alternatively, a cam groove is provided in the phase variable cam, the phase variable cam is fixed in the axial direction, is pivotally supported on the outer shaft so as to be freely rotatable in the phase direction, and the inner shaft is slid in the cam shaft axial direction so as to face the cam groove. The present invention relates to a valve gear that varies the phase of a cam with a pin.

Patent Documents 1 to 6 that vary the phase of the inner shaft with a cam fixed to the outer shaft by a phase variable mechanism are disclosed.
Japanese Patent Laid-Open No. 3-88907 JP 7-224617 A JP-A-9-177517 JP 2002-54410 A JP 2009-293567 A JP 2010-196485 A

Further, Patent Document 7 is disclosed in which the three-dimensional cam fixed to the inner shaft by the inner shaft sliding means is slid to vary the timing, lift amount, and valve opening angle.
JP 2003-3811 A

In DOHC, a method is generally adopted in which a variable phase mechanism (VVT) is arranged between the driven sprocket and the camshaft to change the phase of the entire coaxial so that both suction and / or exhaust can be varied. If one of the intake and exhaust air is variable, or if one intake cam is phase-variable in DOHC, it is necessary to change part of the cams arranged in parallel on the same axis. Patent Documents 1 to 6 are disclosed in which the phase of the inner shaft with respect to the outer shaft is varied by VVT, the cam provided on the outer shaft is a fixed cam, and the cam fixed to the inner shaft is a phase variable cam. In the hydraulic VVT, the response speed is slow, and the response difference is likely to change greatly due to the engine speed, a sudden change in rotation, and the change in accelerator opening, and accurate timing control is difficult. In recent years, the adoption of the electric VVT has increased the response speed, and it has reached a level that can be used for motorcycles that require rapid acceleration, but the timing, lift amount, and valve opening angle can be varied on the intake side. When the so-called VVL is used and the exhaust side is variable in phase, the intake opening time area in the low lift region is narrow in proportion to the output, and the deviation of the overlap amount greatly affects the output and exhaust gas. It is necessary to suppress the response delay to zero as much as possible, and even if an electric VVT is used, there is a drawback that it can be adopted only for an engine in which the engine speed, the rotation change, and the accelerator opening change are suppressed low.
In addition, since Patent Documents 1 to 6 fix the axial direction of the inner shaft and change the phase direction by VVT, the control accuracy of the phase change amount is determined by the accuracy of the VVT control device. If a failure occurs in the low lift range, the exhaust gas will be exhausted when a failure occurs in the low lift range. This is a mechanism that is difficult to adopt due to adverse effects.

Patent Document 7 discloses that the timing, lift amount, and valve opening angle can be varied by sliding a three-dimensional cam lobe fixed to the inner shaft by the inner shaft sliding means, but the cam lobe is variable only in the axial direction and the phase direction is It is fixed and the timing, lift amount, and valve opening angle can be varied by the cam crest shape, and the phase of the flat cam cannot be varied.

The present invention has been made in view of the above-mentioned problems. In the present invention, the camshaft is a double shaft in which a part or all of the cams arranged in parallel on the same axis are phase-shifted. A cam groove is provided in the shaft, outer shaft, or phase variable cam, the phase variable cam is fixed in the axial direction, is pivotally supported on the outer shaft so that the phase direction can be freely rotated, and the inner shaft is slid in the cam shaft axial direction. The cam is phase-shifted by a pin facing the groove, and the cam phase control drive (inner shaft slide drive) can be placed away from the valve operating device, increasing the degree of freedom in size and response speed. The adoption of a large output drive device (motor) that speeds up the operation and the setting of an appropriate reduction ratio are facilitated, and the response speed can be increased as compared with the electric VVT arranged in the driven sprocket section.
Also, when changing the phase of all the coaxial cams or changing the phase of the intake three-dimensional cam slide and exhaust flat cam, the phase of the opposite cam is determined by the cam groove, so the response delay is zero with high accuracy. Even if the cam phase control (accelerator) shaft unit breaks down and stops at its slide position, or shifts to a different slide position, the opposite cam phase is set and the adverse effect is kept small. Can do. Furthermore, since the cam groove can change the phase change amount with respect to the axial movement amount and can be freely set in a curved line, a polygonal line, etc., the phase change amount with respect to the axial movement amount can be reduced to increase the phase variable accuracy, It is possible to freely adjust the exhaust timing according to the timing.

In order to solve the above-mentioned problem, the invention of claim 1 is to change the phase of a part of cams arranged in parallel on the same axis. The camshaft is a double shaft and the pin is fixed to the inner shaft. , Pin guide cam groove whose phase changes in the axial direction is provided on the outer shaft, and the cam whose phase is variable is fixed in the axial direction and is pivotally supported on the outer shaft so as to be freely rotatable, and a groove for guiding the pin is provided in the shaft hole. The phase of the cam is varied by a pin by sliding the inner shaft.
The cam phase control drive unit can be placed away from the valve operating unit, the degree of freedom increases, the adoption of a large output drive unit (motor) that speeds up the response speed, and the setting of an appropriate reduction ratio becomes easy, driven sprocket The response speed can be increased as compared with the electric VVT arranged in the section.

According to a second aspect of the present invention, in the first aspect of the present invention, the rotational direction of the phase fixing cam is fixed to the outer shaft with a key or the like, and the axial direction is fixed to the outer end surface portion of the cam row together with the phase variable cam. It is characterized by being fixed to the outer shaft by.
Since the inner shaft that fixes the pin and the outer shaft that fixes the axial direction of the cam are the same iron-based material, pitch deviation and clearance increase due to thermal expansion differences can be minimized, and high phase variable accuracy can be obtained.

Further, in the invention of claim 3, in which all the cams arranged in parallel on the same axis are phase-variable, the camshaft is a double shaft, the pin is fixed to the inner shaft, and the shaft is fixed to the outer shaft. A pin guide groove is provided in parallel, and the phase-variable cam is fixed in the axial direction and is rotatably supported on the outer shaft, and a pin guide cam groove whose phase changes in the axial direction is provided in the shaft hole. The cam phase is varied by a pin by sliding the shaft.
The phase of the opposing cam is determined by the cam groove, so it can be varied with high accuracy and zero response delay, and even if the cam phase control drive unit fails and stops at that slide position, it shifts to a different slide position However, since the phase of the opposing cam is as set, adverse effects can be suppressed to a small level.

The invention of claim 4 is characterized in that, in the invention of claim 3, the phase change amount with respect to the axial movement amount of the pin guide cam groove is different for each cam.
Since the amount of change can be set differently for each cam, the suction and exhaust timing and overlap can be varied with appropriate settings in SOHC by making a difference in the amount of phase change between the intake cam and the exhaust cam. Further, in DOHC, it is possible to generate a swirl flow by making a difference between the phase change amounts of the left and right intake cams.

The invention of claim 5 is the invention of claim 3, wherein the suction and exhaust cams are arranged in parallel on the same axis, and the phase change direction of the pin guide cam groove of the cam shaft hole is reversed. It is characterized by that.
Since the variable amount of intake and exhaust phases can be increased, it is possible to reduce the overlap amount from zero overlap to negative overlap.

Further, the invention of claim 6 is the invention of claim 5, wherein the suction and exhaust overlap is set small on the low rotation side, and the pin guide cam groove is set so that the overlap becomes large as the rotation becomes high. It is characterized by that.
An appropriate value can be set in the direction of reducing the overlap on the low rotation side, exhaust gas and combustion can be improved, and the intake side can be closed slowly, and fuel consumption can be reduced by reducing pumping loss.

The invention according to claim 7 is the invention according to claim 3, wherein the camshaft phase difference on the camshaft at the center of the roller follower at the end of the valve follower arm portion at the opening and closing of the camshaft axis The phase difference is set to about 1/2 of the phase difference, and the phases of the suction and exhaust cam peaks on the camshaft are substantially matched.
Since the pin guide groove can be made into one and processing becomes easy and the increase in the base circle diameter is suppressed, the engine can be reduced in size and weight and increased in rotation.

In the invention of claim 8, the camshaft is a double shaft, and the intake three-dimensional cam fixed to the inner shaft is fixed in the rotational direction and slid freely in the axial direction. The valve angle is variable and the phase of the coaxially arranged exhaust flat cam is variable. The exhaust flat cam can be rotated on the outer shaft, supported axially, and provided perpendicular to the outer shaft. The pin that is locked to the exhaust flat cam with the rotation direction fixed is fixed in the axial direction and the rotation direction is free. The pin guide cam groove provided on the inner shaft slides on the inner shaft and the exhaust flat on the pin. The cam phase is variable.
With variable exhaust cam phase, only the exhaust valve timing can be changed, and the lift amount and valve opening angle cannot be varied. However, the lift amount and valve opening angle of the exhaust lift curve required between low output and high output are not possible. The timing difference is small, especially the lift amount and the valve opening angle are small, so if the timing can be varied, the performance will be inferior when a 3D cam is also used on the exhaust side, and the head will be more compact and weight reduced. Cost reduction can be achieved.
Since the phase of the exhaust flat cam with respect to the intake three-dimensional cam is determined by the pin guide cam groove, it can be accurately changed with zero response delay, and even if the inner shaft slide drive device fails and stops at its slide position, Even if the slide positions are different, the opposite cam phase is set by the pin guide cam groove, so that adverse effects can be reduced.

The invention of claim 9 is characterized in that, in the inventions of claims 1 to 8, the amount of phase change with respect to the amount of axial movement of the pin guide cam groove is changed.
Because of the cam groove, the amount of phase change relative to the amount of movement in the axial direction can be changed so that it can be freely set, such as a curved line or a polygonal line. The exhaust timing can be freely adjusted in accordance with the timing of the dimension cam.

According to the present invention, the cam phase control (inner shaft slide) drive device can be arranged at a location distant from the valve operating device in the case where the phase of some or all of the cams arranged in parallel on the same axis is variable. The degree of freedom increases, the adoption of a large output drive device (motor) that speeds up the response speed, the setting of an appropriate reduction ratio becomes easy, and the response speed can be increased compared to the electric VVT arranged in the driven sprocket section.
Also, when changing the phase of all the coaxial cams or changing the phase of the intake three-dimensional cam slide and exhaust flat cam, the phase of the opposite cam is determined by the cam groove, so the response delay is zero with high accuracy. Even if the cam phase control (inner shaft slide) drive unit breaks down and stops at that slide position, even if it shifts to a different slide position, the phase of the opposite cam is the same as the setting, so the adverse effect is small Can be suppressed.
Furthermore, since the cam groove can change the phase change amount with respect to the axial movement amount and can be freely set in a curved line, a polygonal line, etc., the phase change amount with respect to the axial movement amount can be reduced to increase the phase variable accuracy, A valve operating device that can freely adjust the exhaust timing in accordance with the timing can be provided.

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 of the first embodiment is a specific example of claims 1 to 7 and 9, and includes a camshaft unit 10 and a rocker arm shaft 27 common to suction and exhaust. Further, the rocker arm unit 20 and the valve unit 30 are included on the intake side, and the rocker arm unit 20EX and the valve unit 30EX are included on the exhaust side.
Moreover, the cam phase control shaft unit 40 which changes a cam phase according to an accelerator opening degree and a driving | running | working condition is included. (See Figures 1-1 to 7)
The left cylinder (side away from the driven sprocket) is shown in claims 1, 2 and 9, and the right cylinder (driven sprocket side) is shown in specific examples in claims 3 to 7 and 9. In addition, to reduce the number of drawings, the left and right cylinders alternative plan (separate figure) is shown, but in the actual machine, the left and right cylinders alternative plan (same figure) is used.

The camshaft unit 10 is sucked into the exhaust valve unit 30EX when viewed from a direction parallel to the camshaft shaft, and is disposed along the exhaust valve unit 30EX inside the exhaust valve shaft V bank. When viewed from the parallel direction, the retainer portion is disposed so as to overlap the cylinder head mating surface side (lower side) from the lower retainer 34 of the retainer portion and overlap the exhaust valve shaft side from the valve unit maximum outer peripheral inclusion line L. (See Fig. 1-2)
The camshaft and the rocker arm shaft are sucked into one, and the camshaft shaft is arranged on the cylinder head mating surface side in the exhaust valve shaft V bank. The cylinder head height that requires the most metal materials can be reduced, and the cylinder head width in the intake and exhaust directions can be reduced, making it possible to reduce the size and weight of the cylinder head and reduce the angle of the intake port with respect to the cylinder axis. In addition, the tumble flow can be improved, the combustion chamber can be increased in compression ratio, and the S / V ratio can be reduced.

In the camshaft unit 10, the camshaft 11 is rotatably supported by the cylinder head 1 and the camshaft housing 2. The camshaft 11 has an exhaust valve opening cam 11EXO and an intake valve closing cam 11C for each cylinder arranged outside the cylinder center as viewed from the direction perpendicular to the cylinder head mating surface, and the cylinder center close to the exhaust valve opening cam 11EXO. An intake valve opening cam 11O is arranged on the side portion on the side, an exhaust valve closing cam 11EXC is arranged in parallel in the axial direction on the side portion on the cylinder center side close to the intake valve closing cam 11C. (See Figures 1-1 and 7)

In the embodiment of the left cylinder (claims 1, 2, 9), the intake valve opening cam 11O and the intake valve closing cam 11C are rotationally fixed by the key 14, and the exhaust valve opening cam 11EXO and the exhaust valve closing cam 11EXC are freely rotatable. The camshaft 11 is pivotally supported, and the outer end surface portions of the intake valve closing cam 11C and the exhaust valve opening cam 11EXO are fixed in the axial direction by the circlip 13 to fix the axial direction of all the cams.
The cam phase control shaft (inner shaft) that fixes the guide pin and the cam shaft (outer shaft) that fixes the cam shaft direction are made of the same iron-based material, minimizing pitch shift and clearance increase due to thermal expansion differences. It is suppressed and high phase variable accuracy is obtained.
In the phase variable cam portion of the camshaft 11, a pin guide cam groove 11G that changes the phase of the cam via the guide roller 41-9 by sliding of the guide pin 41-8 includes an exhaust valve opening cam 11EXO and an exhaust valve closing valve. In the shaft hole portion of the cam 11EXC, pin guide grooves 11EXOG and 11EXCG are provided in parallel in the axial direction so that the head portion of the guide pin 41-8 can be rotatably fixed and slidably faced. (See Figures 1-7 and 8)
In this embodiment, the pin guide grooves 11EXOG and 11EXCG and the head of the guide pin 41-8 are in surface contact, and the grooves are provided in parallel in the axial direction to reduce the surface pressure. In this case, a cam groove whose phase changes in the axial direction can be used, and the cam phase change amount with respect to the cam phase control shaft (inner shaft) movement amount can be increased.
In this embodiment, when adjusting the axial position and clearance of the cam, it is necessary to use the cam.

In the embodiment of the right cylinder (claims 3 to 7 and 9), all the cams are rotatably supported on the camshaft 11, and the outer end surface portions of the intake valve closing cam 11c and the exhaust valve opening cam 11EXO are connected to the circlip 13. The axial direction of all cams is fixed by fixing the axial direction at. The camshaft 11 is provided with a pin guide groove 11G that slides and guides the guide pin 41-8 through the guide roller 41-9 without changing the phase in parallel in the axial direction. Pin guide cam grooves 11OG, 11CG, 11EXOG, and 11EXCG, which change the phase via the guide roller 41-9 by sliding 41-8, change the phase change amount with respect to the axial movement amount by suction and exhaust, and in the opposite phase direction Is provided.
The phase of the opposing suction and exhaust cams is determined by the pin guide cam groove, so it can be varied with high accuracy and zero response delay, and even if the cam phase control shaft unit fails and stops at its slide position, a different slide Even if the position is shifted, the phase of the opposing suction and exhaust cams is as set, so that adverse effects can be kept small.
In addition, since the phase change amount can be set differently for each cam, the suction and exhaust timing and overlap can be varied with appropriate settings in SOHC by making a difference in the phase change amount between the intake cam and exhaust cam. In DOHC, it is possible to generate a swirl flow by making a difference in the amount of phase change between the left and right intake cams.
The camshaft phase difference between the open and closed cam follower arm end of the roller follower center on the camshaft center is set to about 1/2 of the phase difference on the crankshaft of the suction and exhaust lift curves, and the camshaft suction By substantially matching the phases of the exhaust cam crests, the guide pins 41-8 of all cams can be made to have the same phase and the pin guide groove 11G can be made into one, and the pin guide cam grooves 11OG, 11CG, 11EXOG, 11EXCG can be cammed. It can be provided in the mountain range, and the base circle diameter can be kept small.
Since the pin guide groove can be made into one and processing becomes easy and the increase in the base circle diameter is suppressed, the engine can be reduced in size and weight and increased in rotation. (See Figure 1-10)
In this example, a shim 18 is disposed between the outer end surface portion and the circlip 13 so that the axial position and clearance of the cam can be adjusted in a shim-like manner. (See Figure 1-7)
By disposing the exhaust valve opening cam follower arm portion 21EXaO and the intake valve closing cam follower arm portion 21aC outside the cylinder center, an ignition plug hole (injector hole) 1IG can be disposed in the vicinity of the intake side cylinder center. (See Figures 1-1 and 2)
The camshaft 11 has a hollow structure, and a cam phase control shaft 41 is disposed inside the hollow.

The material of the camshaft (cam) in the valve operating system with a valve return spring is generally cast iron, but the forced open / close valve system has no (small) force to turn the camshaft by the spring when the valve is closed. There is a tendency that the mechanical loss in the high rotation range is larger than that with the valve return spring. Reducing the weight of the reciprocating motion part is effective as a countermeasure, and it is necessary to reduce the size of the roller follower part. For this purpose, it is necessary to increase the allowable contact Hertz stress with the cam, and it is desirable that the material of the cam is carburized steel capable of making the allowable contact Hertz stress nearly double that of cast iron.

A driven sprocket 15 is press-fitted and fixed to 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 the boss part. The ignition timing is controlled. 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. (See Fig. 1-1)

Specific specifications of the exhaust valve opening cam 11EXO and the valve closing cam 11EXC are different from those of the intake valve opening cam 110 and the valve closing cam 11C.

As shown in FIG. 1-2, the intake and exhaust rocker arm units 20 and 20EX are arranged on the side (upper side) away from the camshaft unit 10 with respect to the cylinder head mating surface, as viewed from the direction parallel to the camshaft shaft. The exhaust valve unit 30EX close to the camshaft 11 is pivotally supported on a rocker arm shaft 27 disposed near the center of the suction and exhaust valve shaft V bank, away from the camshaft 11.
In the SOHC forced open / close internal combustion engine, the intake / exhaust open / close cams are arranged in parallel in the axial direction on one camshaft. In the small displacement internal combustion engine with a narrow camshaft bearing span, the roller follower portion that contacts the cam is valved. When viewed from the axial direction, it is difficult to dispose the valve unit outside the space between the left and right valves, so that it must be disposed between the left and right valves. Therefore, it is necessary to arrange the roller follower in a place where it does not overlap the valve unit when viewed from the direction parallel to the camshaft axis. In order to set the lever ratio to about 1.8 or less, the rocker arm shaft axis Must be arranged at a position farther from the camshaft shaft than the valve shaft close to the camshaft shaft. The intake / exhaust rocker arm lever ratio should be as close to 1 as possible to reduce lift error and ensure rigidity, but it is ideal for high-speed engines, but the intake lift amount is generally larger than the exhaust lift amount and the cam peak height The intake lever ratio should be increased by the intake / exhaust lift amount ratio, but the lift error will increase and the rigidity will decrease as the lever ratio is increased. If the exhaust lever ratio is large to set the value, the intake lever ratio cannot be increased by the intake / exhaust lift amount ratio. Since it is acceptable in terms of performance if the intake lever ratio is reduced to an equivalent lever ratio where the rigidity of the intake and exhaust rocker arms is comparable, the intake and exhaust valve shafts are sucked into the intake and exhaust joints to bring them closer to the lever ratio. It is arranged near the center of the V bank.

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 portion via a needle bearing 21-3, and is in contact with each cam. The valve-opening cam follower arm portion 21aO and the valve-closing cam follower arm portion 21aC are integrally formed in a V shape sandwiching the cam when viewed from the direction parallel to the camshaft shaft, and in the upper and lower cages of the retainer portion of the intake valve unit 30 Is integrated with a valve lift arm portion 21b that engages through a shim and lifts the valve, and is pivotally supported by a rocker arm shaft 27 arranged in parallel to the camshaft shaft. Is disposed within a substantially stroke range at the center between the upper and lower contact surfaces of the retainer collar in the valve shaft direction. (See Figures 1-2 and 4)
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 Figure 1-3)
In this embodiment, the stroke between the upper and lower contact surfaces of the retainer collar is used to minimize the amount of movement in the direction perpendicular to the valve axis at the contact point between the upper and lower shims of the retainer section at the tip of the valve lift arm and to suppress the force of twisting the valve shaft. The rocker arm swing axis is located near the center, but the valve lift arm swing angle is small and the contact point has a small amount of movement in the direction perpendicular to the valve shaft. If there is, the swing axis may be removed slightly outside the stroke range for the sake of layout.
Roller follower reduces contact resistance with cam, improves valve rigidity by integrating valve lift arm and cam follower arm, adjusts alignment error and secures proper clearance by adjusting shim thickness, etc. By reducing the weight of the moving part, it is possible to reduce the mechanical loss and increase the rotation speed.
The roller follower 21-4 and the needle bearing 21-3 fit the magnitude of acceleration in order to keep the contact Hertz stress with the cam and the pin 21-2 within an allowable range and to make the bearing life longer than the set durability time. Although it is necessary to make the dimensions, it is necessary to reduce the size as much as possible from the viewpoint of reducing mechanical loss and increasing the rotation speed. Therefore, the roller follower 21-4, the needle bearing 21-3, and the pin 21-2 are generally made of bearing steel or carburized steel. However, a special heat treatment or shot peening is added to the material. It should improve hertz stress and wear resistance.
As a method of appropriately adjusting the clearance between the cam base circle and the roller follower, it is practical to adjust the outer diameter of the roller follower, and the roller follower diameters of both the valve-opening cam follower arm portion 21aO and the valve-closing cam follower arm portion 21aC. It is more efficient to adjust one with a predetermined roller follower diameter than to adjust the other. The method of adjusting with the diameter of one roller follower was adjusted to the size that is considered to be the appropriate clearance, as well as the method of temporarily assembling the actual head and measuring the appropriate outer diameter with a jig to assemble one roller follower. It is possible to prepare several types of rocker arms in advance, measure the clearance after provisional assembly on the actual head, and selectively assemble the appropriate one, but the former method is for small-scale production and the latter method is for mass production. It can be said that the method is suitable.

The valve lift arm portion 21b is formed in two comb shapes in the vicinity of the left and right valve shafts in the axial direction of the swing shaft portion 21c. And are connected by a connecting arm 21e. 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 swinging shaft portion 21c. The swing shaft portion 21c is provided in the axial direction so as to be divided in the vicinity of the left and right valve lift arms, and the right swing shaft portion 21EXcR of the exhaust rocker arm 21EX is disposed between the left and right swing shaft portions 21cR and 21cL. A left swing shaft portion 21EXcL of the exhaust rocker arm 21EX is disposed on the left side of the swing shaft portion 21cL, and is pivotally supported by the rocker arm shaft 27 so as to be swingable. The left and right swing shaft portions 21cR and 21cL are connected by a connecting arm 21f, and are formed in a square shape by the valve lift arm portion 21b, the swing shaft portion 21c and the connecting arms 21e and 21f, An ignition plug hole (injector hole) 1IG is disposed substantially parallel to the intake valve unit 30. (See Figures 1-2, 3, 4, and 7)
Since the rocker arm's rocking shaft can be made to have two long spans on the left and right, flutter can be suppressed and the lift error of the left and right valves can be reduced. In addition, the rocker arm rigidity and rocking bearing hole machining accuracy can be improved by connecting the left and right rocking shafts.
The ignition plug hole (injector hole) 1IG can be arranged without increasing the intake and exhaust valve shaft V bank angle and the camshaft bearing span, and the ignition or injection center can be arranged substantially at the center of the cylinder, and the inclination with respect to the wall surface of the combustion chamber Because it can be made smaller, there is no need to create a recess in the combustion chamber to expose the electrode at the tip of the spark plug to the combustion chamber or to prevent the fuel injected from the tip of the injector from hitting the wall of the combustion chamber. It does not cause a decrease and deterioration of the S / V ratio.
In addition, since the ignition plug hole (injector hole) 1IG disposed on the intake side 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 require cooling from the intake port side. Become. (See Figure 1-14)
In this embodiment, the engagement portion with the retainer shim at the tip of the valve lift arm portion 21b is bifurcated, and the contacts are two points on the left and right per valve. However, in the case of a forced opening and closing valve device, there is no valve spring. However, even if a coil spring is used, the spring force is weak because it is used as a valve seal spring, and the force to turn the valve around the stem axis during lift is weak, preventing the uneven wear of the umbrella part. Since it is low, you may make it turn around a stem axis | shaft by stopping a fork and only contacting the collar part of one side.
However, since the force of lifting the valve is strong, other measures may be required for a small engine with a thin valve stem shaft or a high-speed engine.
A valve return spring is obtained by sandwiching the opening / closing cam with a V-shaped cam follower arm and engaging the end of the valve lift arm integral with the cam follower arm into the upper and lower flanges of the retainer fixed to the valve. Without it, the cam lift curve can be transmitted to the valve within the range including the clearance of each part.

As shown in FIG. 1-5, the exhaust rocker arm 21EX has a middle valve lift arm portion 21EXbC formed in a comb shape from the right swing shaft portion 21EXcR along the right valve lift arm portion 21EXbR of the valve lift arm portion 21EXb. The roller follower of the middle valve lift arm portion 21EXbC and the right valve lift arm portion 21EXbR is rotatably and press-fitted via a needle bearing 21-3 to a pin 21-2 that is fixed by press fitting at a position where it does not contact the retainer portion. It is basically the same as the intake rocker arm 21 except that a roller follower 21-4 that is supported and is in contact with each cam is disposed and the cam follower arm portion and the valve lift arm portion are shared.
By sharing the cam follower arm portion and the valve lift arm portion, the rocker arm can be reduced in weight and rigidity.

The rocker arm shaft 27 is inserted into a bearing hole provided in the camshaft housing 2, and is locked in the axial direction by a stepped portion 27 a and a circlip 28. (See Figure 1-3)
The rocker arm shaft 27 has a hollow structure, and both ends are plugged with plugs 27-2 to form a lubricating oil passage. The oil is supplied by the oil supplied through the lubricating oil passage formed in the cylinder head and the cam housing. The rocking shafts 21c and 21EXc of the exhaust rocker arms 21 and 21EX are lubricated, and the needle bearing 21-3, the cam crest, and the roller follower 21-4 are lubricated by oil jet injection. (See Figures 1-3 and 5)
In addition, by utilizing the hollow structure of the rocker arm shaft 27, a lubricating oil passage is provided in the camshaft housing to lubricate the bearing portion of the camshaft 11. (See Figure 1-7)

As shown in FIG. 1-2, the intake valve unit 30 includes two intake valves 31 in which an intake valve stem 31a is guided by an intake valve guide 1-3.
When the intake valve 31 is lifted, the air is introduced from the air cleaner and intake pipe (not shown) through the intake port 1IN and the flow rate is controlled by the control valve (not shown), and the injector is introduced into the intake passage or the combustion chamber. A mixture with fuel sprayed from (not shown) is introduced into each cylinder.

In the embodiment shown in FIG. 1-2, a conical split cotter generally used in a valve operating device with a valve return spring is used as a locking piece (33), and the vicinity of the top of each intake valve stem 31a is used. A cotter 33 locked in the cotter groove has a tapered portion that engages with the cotter on the lower inner side of the cylinder portion, and a set screw 35 is tightened on a lower retainer 34 having a female screw on the upper inner side and a flange on the lower outer side. The retainer portion with the upper and lower hooks is formed by fixing to the intake valve 31 and tightening the hook nut 36 on the set screw 35.
Since the locking piece (33) only needs to be fixed in the axial direction of the lower retainer, various locking pieces are conceivable, such as using a ring with a circular cross section or a semicircular locking piece with a circular cross section.
The shim can be inserted between the cage and the retainer contact part of the valve lift rocker arm part, but it is made difficult to loosen by tightening the male screw with two nuts.
A flat washer-shaped shim 37 is disposed between the tip of the valve lift arm portion 21b and the upper and lower flanges of the retainer portion, and the thickness thereof is adjusted to adjust the alignment error and ensure proper clearance. (See Fig. 1-2)

Since the flat washer-shaped shim 37 does not have a function of absorbing the angle error, it is necessary to provide crowning at the tip of the valve lift arm 21b so that the end of the contact with the tip of the valve lift arm 21b does not become an end. 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. 1-13 shows an angle error absorbing shim corresponding to a small engine with a thin valve stem shaft and a high-speed engine, which absorbs the angle error and prevents the valve from being lifted and lifted. The retainer collar side contact surface 37a of the shim 37 has a mountain shape, and the contact is formed in a line substantially perpendicular to the rocker arm swinging shaft, and the valve axial direction is in contact with the contact line between the shim 37 and the shim contact portion at the tip of the valve lift arm 21b. By providing a stopper 37b that is substantially orthogonal and holds the orthogonality, the angle error in the forward direction is absorbed, and the shim 37 and the valve lift arm 21b are always provided even if there is no crowning at the tip of the valve lift arm 21b. The contact of the shim contact portion at the tip is kept linear, and the contact hertz stress can be reduced to reduce wear.
Generally, the material of the lower retainer 34 and the hooked nut 36 is steel. However, when titanium or aluminum is used to reduce mechanical loss and increase the rotation speed, the shim 37, the lower retainer 34 and the hooked nut 36 are hooked. A steel washer is added between the nuts 36 so that it can withstand contact Hertz stress with the chevron-shaped portion of the retainer rod side contact surface 37a.

The valve spring 39 that seals the valve seat and valve face in close contact with each other when seated on the valve is a disc spring, reducing the weight of the reciprocating part and preventing the valve stem from being pushed up by the valve stem thermal expansion. The gap between the shim and the retainer is pressed by a disc spring and kept at 0 at all times to reduce noise.
Since the undulation of the lift curve can be suppressed by the Belleville spring load, the shape of the contact part at the tip of the valve lift arm is a circle with the diameter obtained by subtracting the appropriate clearance from the dimension between the upper and lower shim contact surfaces. It is possible to reduce the mechanical loss by making the directional dimension constant. Utilizing the characteristics of a disc spring that can make the load characteristics non-linear, the difference between the mounting load and the maximum compression load can be reduced to reduce mechanical loss.
The disc spring of the valve spring 39 is disposed between the upper shim 37 and the hooked nut 36, and the hooked nut 36 is provided with a stepped pocket 36a in which the valve spring 39 is accommodated. In this embodiment, the stepped pocket is provided in the hooked nut 36, but it may be provided in the upper shim 37.
The procedure for setting the clearance between the tip of the valve lift arm and the shim and retainer necessary to prevent the valve from being pushed up due to thermal expansion of the valve stem is as follows. First, the shim 37 is inserted into the retainer at the top and bottom of the tip of the valve lift arm. The nut 36 is tightened with the spring 39 removed. After that (when the air conditioner is not lifted), swing the rocker arm to the side where the valve does not lift (in this case, the valve lift arm is on the upper side) and press the roller follower against the cam. Shim so that the gap between the side shim is about 0.1 mm on the intake side and about 0.2 mm on the exhaust side (so-called tape clearance), and the gap between the tip of the valve lift arm and the upper shim is kept to a minimum. Adjust the thickness. After adjusting the shim thickness, insert the disc spring 39.
In this embodiment, a disc spring is employed to narrow the suction and exhaust V bank angle, but a coil spring may be disposed as a seal spring between the lower retainer and the cylinder head.

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

An ignition plug hole (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) 1IG. Yes.
The ignition plug hole (injector hole) 1IG is seen from a direction perpendicular to the cylinder head mating surface between the intake valve unit 30 and the camshaft unit 10 and the intake and exhaust rocker arm shaft units 20 and 20EX, as viewed from the direction parallel to the camshaft axis. As viewed, the left and right valve lift arms 21bR and 21bL of the intake rocker arm, the valve closing cam follower arm 21aC, and the valve opening cam follower arm 21EXaO of the exhaust rocker arm are arranged. (See Figures 1-1, 2 and 3)
Using the space created by making the lever ratio of the rocker arm that lifts the valve far from the camshaft shaft the same as the lever ratio of the valve near the camshaft shaft, the spark plug hole (injector hole) 1IG is far from the camshaft shaft. A valve lift arm of a rocker arm that is arranged substantially parallel to the valve and lifts a valve far from the camshaft axis (disposed perpendicularly to the rocker arm shaft axis through the valve axis when viewed from the direction perpendicular to the cylinder head mating surface) By disposing them in between, the ignition plug hole (injector hole) 1IG can be disposed without increasing the suction, exhaust valve shaft V bank angle and camshaft bearing span, and the ignition or injection center can be disposed substantially at the center of the cylinder. Since the inclination with respect to the wall of the combustion chamber can be reduced, There is no need to make a recess in the combustion chamber to expose the tip electrode to the combustion chamber or to prevent the fuel injected from the injector tip from hitting the wall of the combustion chamber, reducing the compression ratio and the S / V ratio. Does not cause any deterioration.

The cam phase control 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.
In the embodiment of the left cylinder (claims 1, 2 and 9), the cam phase control shaft 41 is press-fitted with a guide pin 41-8 in the phase variable cam portion, and the cam phase control shaft 41 is guided by the guide roller 41-. 9, the phase of the cam phase control shaft 41 and the guide pin 41-8 with respect to the camshaft 11 is changed by sliding along the pin guide cam groove 11G of the camshaft 11, and the head of the guide pin 41-8 The phase of the exhaust valve-opening cam 11EXO and the exhaust valve-closing cam 11EXC whose phases are fixed can be varied. In addition, the guide roller 41-9 is contacted with the pin guide cam groove 11G at the time of sliding to reduce sliding resistance, increase the phase variable speed, and prevent wear by making the contact point around the guide roller. However, the cam phase fluctuation is reduced and is not indispensable and can be abolished. (See Figures 1-7 and 8)
In this example, before the cam phase control shaft is slid, the intake and exhaust overlap is set small (solid line) for the engine with valve return spring (dotted line) that does not change the phase (solid line), and the overlap is increased by sliding (two points). Chain line). By making the low rotation side before sliding and sliding on the high rotation side, it is possible to achieve both reduction of exhaust gas and high output. In this example, the opening area is expanded without changing the operating angle and lift height with the valve return spring by forced opening and closing, and the aim is to improve the output, but the effective area (product of opening area and flow coefficient) Since the angle of view can be narrowed by making them equal, the options for further reducing fuel consumption and exhaust gas will be expanded. (See Figure 1-11)

In the embodiment of the right cylinder (claims 3 to 7, 9), the cam phase control shaft 41 is press-fitted with guide pins 41-8 in the same phase in all cam portions, and the cam phase control shaft 41 is guided by the guide roller. The pin of all the cams which the guide roller 41-9 of the head side of the guide pin 41-8 engages by sliding without changing a phase along the pin guide groove 11G of the camshaft 11 via 41-9 By sliding along the guide cam grooves 11OG, 11CG, 11EXOG, and 11EXCG, the phase of all the cams can be varied. In this example, the pin guide cam groove is provided in the suction and exhaust reverse phase direction, and the suction and exhaust overlap is reduced with respect to the engine with a valve return spring (dotted line) that does not change phase before sliding the cam phase control shaft. In addition, the intake is set to be closed slowly (solid line), and the overlap is made larger by sliding (two-dot chain line). By making the low rotation side before sliding and sliding on the high rotation side, it is possible to achieve both pumping loss and exhaust gas reduction by the slow closed mirror cycle on the low rotation side, and high output on the high rotation side. (See Figures 1-9 and 12)
Further, a bearing 41-5 is inserted into a stepped shaft portion at one end of the cam phase control shaft 41, and an inner race is fixed by a nut 41-7 with no backlash in the axial direction. The outer race of the bearing 41-5 is beveled with a joint bracket 44-2 that is press-fitted and fixed to the male screw shaft 44-1 of the cam phase control shaft slide actuator unit 44 and guides the slide while restricting the rotation of the male screw shaft 44-1. The circlip 41-6 is fixed in the axial direction. The joint bracket 44-2 is provided with a groove for engaging the tip of the detection arm 73 of the cam phase control shaft slide sensor 72. The slide amount of the cam phase control shaft 41 is detected by the phase change of the detection arm 73, and the cam phase. The control motor 45 is controlled. (See Figures 1-1 and 7)

In the cam phase control shaft slide actuator unit 44, a driven gear 44-4 is rotatably supported on the cylinder head 1 by bearings 44-8a and 44-8b and housings 44-7R and 44-7L. Is fixed to the driven gear 44-4 in the axial direction by a bevel-shaped circlip 44-6 and the stepped portion of the housing 44-7L and the bevel-shaped circlip 44-9 have no axial clearance. The axial play of the driven gear 44-4 is minimized by using a four-point contact bearing.
In this embodiment, the cam phase control shaft is driven by the rotation of the cam phase control motor 45 by setting the female screw portions of the male screw shaft 44-1 and the driven gear 44-4 as trapezoidal screws and setting the lead inclination angle to a friction coefficient or less. 41 can be slid, but the sliding force of the cam phase control shaft 41 prevents the cam phase control motor 45 from rotating, eliminates the need for holding power when the phase is fixed, and causes a phase when the motor is locked in the unlikely event. It has a function to fix and hold.
The drive gear 45-2, which is press-fitted and fixed to the output shaft of the cam phase control motor 45 fixed to the cylinder head 1, meshes with the driven gear 44-4, and the cam phase control motor 45 corresponding to the accelerator opening degree and the traveling situation. The rotation of the output shaft is converted into the slide of the cam phase control shaft 41, that is, the phase variable motion of the phase variable cam. (See Figures 1-1 and 7)
The cam phase control unit can be placed at a location away from the valve operating device, increasing the degree of freedom in size, and adopting a large output drive device (motor) that speeds up the response speed, making it easy to set an appropriate reduction ratio, and driving sprockets The response speed can be increased as compared with the electric VVT arranged.
The cam phase control drive unit is a combination of the cam phase control shaft slide actuator unit 44 and the cam phase control motor 45.

The valve operating apparatus according to the second embodiment is a specific example of claims 8 and 9 and is provided on the same camshaft with a three-dimensional cam on the intake side and a flat cam on the exhaust side, and the intake cam lobe slides to the maximum lift side. An exhaust cam is arranged on the side where the camshaft and one rocker arm shaft are viewed from the camshaft axial direction, near the cylinder shaft, and the rocker arm shaft is arranged on the cylinder head mating surface side with respect to the camshaft. The so-called SOHC is a swing arm type rocker arm, and includes a camshaft unit 10, an intake swing arm unit 20, an exhaust swing arm unit 20EX, an intake valve unit 30, and an exhaust valve unit 30EX. Also included is an accelerator shaft unit 40 that is arranged coaxially with the camshaft and slides the intake cam lobe in accordance with the accelerator opening and the traveling state and varies the exhaust cam phase. (See Figures 2-1 to 4)
Since the camshaft and the rocker arm shaft are aligned in the cylinder axis direction, the cylinder head becomes high, but the cylinder head width in the intake and exhaust directions can be narrowed to make a compact cylinder head, 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 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 arranged in the vicinity of the center of the cylinder shaft as viewed from the direction parallel to the camshaft axis, and together with the accelerator shaft unit 40 arranged coaxially, the camshaft unit 10 is aligned with the upper and lower camshaft housings 2U and 2L. It is a surface. (See FIG. 2-2).
Since the center hole cannot be used as an oil passage, the bearing portion is lubricated from the oil passage in the center hole of the rocker arm shaft through the oil passage of the lower camshaft housing 2L. (See Fig. 2-4)

In the camshaft unit 10, the camshaft 11 is rotatably supported by the lower camshaft housing 2L and the upper camshaft housing 2U. 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. Thus, the slide is guided while the phase of the cam lobe with respect to the cam shaft of the intake cam lobe 12 fixed to the accelerator shaft 41 is regulated.
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. 2-4, the cam crest on the slide direction side becomes lower and becomes higher gradually as it becomes the opposite side in the slide direction. On the opposite side of the sliding direction, the flange 41 and the end of the intake cam lobe 12 are connected to the hole 41 of the intake cam lobe 12 so that the rising portion 41-2a of the key 41-2 is sandwiched without any axial clearance. -4 is press-fitted to minimize the backlash in the axial direction of the intake cam lobe 12 with respect to the key 41-2, and minute clearances are provided in the phase direction and the radial 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 exhaust cam 11EX has a camshaft 11 that is rotatable and fixed in the axial direction by a circlip 13 on the side where the intake cam lobe 12 slides to the maximum lift side at a phase corresponding to the ignition timing of each cylinder. The shaft hole is provided with a groove 11EXG that engages with the head of the guide pin 41-8 in a fixed rotational direction. Further, the base circle diameter of the exhaust cam 11EX is set larger than the base circle diameter of the intake cam lobe 12.
The guide pin 41-8 is disposed so as to be axially fixed and swingably rotatable in a groove 11G formed in the camshaft 11 in the rotational direction. (See Figures 2-1, 2, and 4)
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. In addition, by setting the exhaust cam base circle diameter larger than the intake cam lobe, even if the cam crest height on the low lift side of the intake cam lobe is set higher, the roller follower support arm of the exhaust swing arm and the camshaft shaft Even if it overlaps in the direction, it can be made difficult to contact, 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.

A driven sprocket 15 is press-fitted and fixed to one end of the camshaft 11, and is axially fixed and rotatably supported on the camshaft housing by an end surface of the driven sprocket 15 and a flange provided on the camshaft 11. A pin 67, which is a projection for a cam phase detection sensor, is press-fitted and fixed to the boss portion of the driven sprocket 15. The phase is detected by the phase sensor unit 71 and the ignition timing is controlled by the output signal. (See Figures 2-1, 2, and 4)
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 intake swing arm unit 20 and the exhaust swing arm unit 20EX are cylinder cylinder shafts as viewed from a direction parallel to the cam shaft axis on the cylinder head mating surface side (lower side) with respect to the cam shaft unit 10. The rocker arm shaft 27 is disposed near the center, and the axis center of the rocker arm shaft 27 is the mating surface of the cylinder head 1 and the lower camshaft housing 2L.
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 lift 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. 2-5, the intake swing arm 21 is rotatably supported via a needle bearing 21-3 on a pin 21-2 that is press-fitted and fixed to the tip, and is a roller follower 21 that makes point contact with each cam. -4, and a valve lift arm portion 21b that pushes the stem top portion of the intake valve unit 30 through the adjusting screw 22 to advance and retreat the valve, as viewed in a direction parallel to the camshaft shaft, is a T-shape. It is a so-called roller swing arm that is integrally formed and is pivotally supported on a rocker arm shaft 27 that is arranged in parallel with the camshaft shaft. 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)
The outer cross-sectional shape of the roller follower 21-4 requires countermeasures against fretting corrosion that occurs when there is no lift. The maximum outer diameter is set to the maximum R, and R is set to the maximum R that can absorb the alignment error between the camshaft unit and the rocker arm unit. In the axial direction in which the cam peak height and the working angle increase, R is a barrel shape having a small outer diameter with a quadratic curve. (See Figure 2-13)
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 ′. (The solid line in Figure 2-13)
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 the amount of lift and noise caused by an increase in tappet clearance. As a countermeasure, a cylindrical surface is connected to the side of the spherical outer peripheral surface as shown by a two-dot chain line in Fig. 2-13. A method for reducing fretting corrosion wear by reducing the surface pressure by linear contact of the roller follower has already been disclosed, but the one that moves the left and right valves at the arm tip extended on both sides of the roller follower has a balance function. By pressing the cam and the roller follower cylindrical surface with the left and right valve spring reaction forces on both ends of the arm, The force that follows the cylindrical surface of the Lafollower acts and absorbs the alignment error, so the effect of providing the cylindrical surface is obtained. However, if the rocker arm type is used, the alignment is fixed and there is almost no function to absorb the alignment error. However, the contact amount increases only at both ends A and B of the cylindrical surface, resulting in a large amount of wear. In particular, the wear at the 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.

The valve lift arm portion 21b is formed in a comb shape in the vicinity of the position of the cam follower arm portion 21a in the swing axis direction from one of the swing shaft portions 21cR and 21cL which are divided by left and right in the axial direction and connected by the arm 21f. And (adjusting screw boss 21d is provided at the tip of the valve stem shaft in the vicinity of the right valve lift arm 21bR and the left valve lift arm 21bL). (See Fig. 2-3)
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.

As shown in FIG. 2-6, the exhaust swing arm 21EX is rotatably supported by a pin 21EX-2 that is press-fitted and fixed to the tip portion via a needle bearing 21EX-3, and is a roller follower 21EX that makes line contact with each cam. -4, and a valve lift arm 21EXb that pushes the stem top of the exhaust valve unit 30EX through an adjusting screw 22 to advance and retreat the valve, as viewed from a direction parallel to the camshaft shaft, is formed in a T shape. It is a so-called roller swing arm that is integrally formed and is pivotally supported on a rocker arm shaft 27 that is arranged in parallel with the camshaft shaft. 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)

The valve lift arm portion 21EXb 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 21EXcR and 21EXcL that are divided into left and right in the axial direction (the right valve lift arm portion 21EXbR and The left valve lift arm portion 21EXbL) and an adjusting screw boss 21EXd are provided at the tip portion near the valve stem shaft and connected by the arm 21Exe. (See Fig. 2-3)
In the present embodiment, the U-shaped arm is not connected between the left and right swing shafts by an arm, but may be a U-shaped arm that is connected by an arm and improves rigidity and strength.
The right swing shaft portion 21EXcR of the exhaust swing arm 21EX is disposed between the swing shaft portions 21cR and 21cL of the intake swing arm 21.
By arranging one swinging shaft part of the other swing arm between the split swinging shaft parts, the total swinging shaft part width when assembling the two swing arms is one swing arm swinging Since the width of the shaft and the width of the outer side surface of the two swing shafts of the other swing arm are added, the shim can be adjusted without being affected by the pitch crossing between the swing shafts. The flutter in the swing axis direction can be minimized.

The positions of the intake swing arm 21 and the exhaust swing arm 21EX in the swing axis direction are fixed to both the exhaust swing arm left swing shaft portion 21EXcL and the intake swing arm right swing shaft portion 21cR on both outer sides of the thrust washers 24 and on both outer sides thereof. The circlip 26 or the rocker arm shaft 27 stepped portion 27a locked in the circlip groove of the shim 25 and the rocker arm shaft 27 is arranged, and the axial clearance of the swinging shaft portion is adjusted by adjusting the thickness of the horseshoe shim 25 At the same time, the position of the intake swing arm 21 in the swing axis direction is adjusted.
The horseshoe-shaped shim 25 is provided with a concave portion 25a in a part thereof, the tip protrusion 51a of the locking piece 51 is exposed to the concave portion 25a, and the locking piece 51 is fixed with a bolt 51-2 to prevent the shim from coming off and rotating.
The circlip 26 determines the phase by the circlip phasing bosses 1-5, 2LR-2, 2LC-2 and the locking piece tip protrusions 51a provided on the cylinder head 1 and the lower camshaft housing 2L. To prevent contact. (See Figures 2-3, 7, and 8)
By adopting a roller swing arm as a valve lifter, the rigidity and reciprocating part weight are slightly disadvantageous compared to the direct hitting type, but the cam angle becomes lower and the inclination becomes weaker because of the lever ratio, so the change in operating angle can be increased, Since the cam is displaced from the upper side of the valve shaft, there is an advantage that the tappet clearance can be easily adjusted.
However, since the variation of the lift amount by the lever ratio is increased by using the roller swing arm, 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).
Since the shim has a horseshoe shape, it can be inserted into the rocker arm shaft with the roller swing arm assembled, so after the cylinder head is assembled to the cylinder, all the valve system parts are assembled and the head cover is not assembled. By this, the tuning (inter-cylinder lift amount adjustment) can be performed precisely and efficiently without re-disassembling the valve system parts.
Further, by fixing the position of the swing shaft in the swing shaft direction by shim adjustment in a state where the both swing shaft outer surfaces of the intake swing arm and one swing shaft portion of the exhaust swing arm are abutted and the clearance is eliminated, Both axial backlashes can be minimized. Precise output control becomes possible by suppressing variations in the intake side lift.

The rocker arm shaft 27 is clamped and clamped in bearing holes provided in the cylinder head 1 and the lower camshaft housing 2L without radial clearance, and a stepped portion 27a provided in the vicinity of the mounting of the housing 44-7 of the accelerator shaft slide actuator unit 44. A bevel-shaped circlip 28 is assembled to the cylinder head 1 and the lower camshaft housing 2L without any axial clearance. (See Figures 2-2, 3, and 4)
The rocker arm shaft 27 has a hollow structure, and one end is plugged with a plug 27-2 to form a lubricating oil passage. The oil is supplied through the lubricating oil passage formed in the cylinder head and the camshaft housing. The shaft 11 bearing portion, the swinging shaft portion 21c of the intake swing arm 21 and the swinging shaft portion 21EXc of the exhaust swing arm 21EX are lubricated, and the needle bearings 21-3 and 21EX-3, the cam peak portion, and the roller follower 21-4 are lubricated. , 21EX-4 is oil jet spray lubricated. (See Figures 2-3 and 4)

As shown in FIG. 2B, the intake valve unit 30 includes two intake valves 31 in which an intake valve stem 31a is guided by an intake valve guide 1-3.
When the intake valve 31 is lifted, air that is guided from an air cleaner and an intake pipe (not shown) through the intake port 1IN and whose flow rate is mainly controlled by the valve lift amount is injected into the intake passage or the combustion chamber (see FIG. An air-fuel mixture with fuel sprayed from (not shown) is introduced into each cylinder.

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

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

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.
On the exhaust cam 11EX side of the accelerator shaft 41, a pin guide cam groove 41G whose guide pin 41-8 is phase-shifted by sliding the accelerator shaft 41 through a guide roller 41-9 is engraved. As a result, the amount of phase change relative to the accelerator shaft slide amount (the amount of movement of the pin guide cam groove in the axial direction) can be freely changed such as a polygonal line or a curved line. (See Figures 2-1, 2, 4, and 11)
With variable exhaust cam phase, only the exhaust valve timing can be changed, and the lift amount and valve opening angle cannot be varied. However, the lift amount and valve opening angle of the exhaust lift curve required between low output and high output are not possible. The timing difference is small, especially the lift amount and the valve opening angle are small. If the timing can be varied, the same performance can be obtained when a three-dimensional cam is used on the exhaust side, and the head is made compact and weight is reduced. Cost reduction can be achieved.
Since the phase of the exhaust flat cam with respect to the intake three-dimensional cam is determined by the pin guide cam groove, it can be accurately changed with zero response delay, and even if the inner shaft slide drive device fails and stops at its slide position, Even if it is shifted to a different slide position, since the phase of the opposing cam is as set, the adverse effect can be suppressed small. In addition, it is possible to increase the phase variable accuracy by reducing the phase change amount with respect to the axial movement amount in a part of the slide region, or to freely adjust the exhaust timing in accordance with the timing of the intake three-dimensional cam.
In this example, before the accelerator shaft is slid (intake low lift side), the intake and exhaust overlaps are set smaller (solid line) than when the exhaust cam is not phase-shifted (dotted line), and it is over on the slid high lift side. The lap is set large (dashed line). In the intermediate lift region, the pin guide cam groove 41G has a shape that is optimally overlapped with each intake lift curve (see FIG. 2-11). (See Figure 2-12)
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.
The outer race of the bearing 41-5 is press-fitted and fixed to the male screw shaft 44-1 of the accelerator shaft slide actuator unit 44, and a joint bracket 44-2 that guides the slide while restricting the rotation of the male screw shaft 44-1 is press-fitted. It is fixed. 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 2-1, 2, 4, 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. The housing 44-7 is split in two and positioned by a knock pin 44-7K and fixed to the cylinder head 1 by a bolt 44-7B. 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 2-1, 4, 10)
The combination of the accelerator shaft slide actuator unit 44 and the accelerator motor 45 is an inner shaft slide drive device.

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) 1IG. The exhaust valve unit 30EX is disposed in a valve lift arm formed in a square shape of the exhaust swing arm 21EX substantially parallel to the exhaust valve shaft. (See Figures 2-1 and 2)

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 embodiment, the same code | symbol is used for the member which is the same as that of 1st embodiment, or respond | corresponds.

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 EE line of FIGS. 1-3. It is sectional drawing which follows the DD line | wire of FIGS. 1-2. It is sectional drawing which follows the FF line of FIGS. 1-5. It is sectional drawing which follows the GG line of FIGS. 1-2. FIG. 8 is a developed sectional view taken along line HH in FIG. 1-7. FIG. 8 is a developed sectional view taken along line JJ in FIG. It is sectional drawing which follows the KK line | wire of FIGS. 1-7. It is a valve lift curve figure of a left cylinder (Claims 1, 2, 9) embodiment. It is a valve lift curve figure of a right cylinder (Claims 3-7, 9) Example. It is a detailed view of an angle error absorption shim. It is an exhaust port sectional view (water passage diagram). (MM sectional view of FIG. 1-2)

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 of FIGS. 2-2. It is sectional drawing which follows the GG line of FIGS. 2-3. It is sectional drawing which follows the HH line | wire of FIGS. 2-3. It is sectional drawing which follows the JJ line of FIGS. It is sectional drawing which follows the KK line | wire of FIGS. FIG. 5 is a developed sectional view taken along line LL in FIG. 2-4. It is a valve lift curve figure. It is a roller follower sectional shape detail drawing.

1 Cylinder head 1IN Intake port 1EX Exhaust port
1IG spark plug hole (injector hole)
1-2 Intake valve seat 1-2EX Exhaust valve seat 1-3 Intake valve guide 1-3EX Exhaust valve guide 1-4 Sand hole plug 1-5 Circlip phasing boss 2 Camshaft housing 2L Lower camshaft housing 2LR Bottom Right camshaft housing
2LC lower middle camshaft housing
2LL lower left camshaft housing
2LR-2 circlip phasing boss
2LC-2 circlip phasing boss 2U Upper camshaft housing 2UR Upper right camshaft housing
2UC Upper and middle camshaft housing
2UL Upper left camshaft housing 2-1 Bolt 3 Cylinder head cover 3-2 Cylinder head cover gasket 3-3 Cylinder head cover bolt 4 Accelerator shaft unit cap 4-1 O-ring 10 Camshaft unit 11 Camshaft 11G Pin guide (cam) groove 11O Inlet valve opening cam 11OG Pin guide cam groove 11C Inlet valve closing cam 11CG Pin guide cam groove 11EX Exhaust cam 11EXG Guide pin engaging groove 11EXO Exhaust valve opening cam 11EXOG Pin guide (cam) groove 11EXC Exhaust valve closing cam 11EXCG Pin guide (cam) ) Groove 12 Intake cam lob 13 Circlip 14 Key 15 Driven sprocket 18 Shim 20 Intake rocker arm (swing arm) unit 21 Intake rocker arm 21a Cam Follower arm
(Swing arm) 21aO Valve opening cam follower arm
21aC Valve closing cam follower arm
21b Valve lift arm
21bR Right valve lift arm
21bL Left valve lift arm
21c Oscillating shaft
21cR Right swing shaft
21cL Left swing shaft
21d Adjust screw boss
21e Connecting arm
21f Connecting arm 21-2 Pin 21-3 Needle bearing 21-4 Roller follower 20EX Exhaust rocker arm (swing arm) unit 21EX Exhaust rocker arm 21EXa Cam follower arm
(Swing arm) 21EXaO Valve opening cam follower arm
21EXb Valve lift arm
21EXbR Right valve lift arm
21EXbC Middle valve lift arm
21EXbL Left valve lift arm
21EXc Oscillating shaft
21EXcR Right swing shaft
21EXcL Left swing shaft
21EXd Adjust screw boss
21EXe connecting arm 21EX-2 pin 21EX-3 needle bearing 21EX-4 roller follower 22 adjusting screw 23 nut 24 thrust washer 25 horseshoe shim 25a recessed part 26 circlip 27 rocker arm shaft 27a stepped part 27-2 plug 28 (bevel type) sir Clip 30 Intake valve unit 31 Intake valve 31a Intake valve stem 30EX Exhaust valve unit 31EX Exhaust valve 31EXa Exhaust valve stem 32 Valve stem seal 33 Locking piece (cotter)
34 (Lower) Retainer 34a Cylindrical guide 35 Set screw 36 Nut with flange 36a Stepped pocket 37 Shim 37a Retainer collar side contact surface
37b Stopper 38 Valve spring seat 38a Cylindrical guide 39 Valve spring 40 Cam phase control (accelerator) shaft unit 41 Cam phase control (accelerator) shaft 41G Pin guide cam groove 41-2 Key 41-2a Rising part 41-3 Bolt 41- 4 Pin with Pin 41-5 Bearing 41-6 Bevel Circlip 41-7 Nut 41-8 Guide Pin 41-9 Guide Roller 44 Cam Phase Control (Accelerator) Shaft Slide Actuator Unit 44-1 Male Screw Shaft 44-2 Joint Bracket 44-3 Female thread boss 44-3a Spacer 44-4 Driven gear 44-5 Key 44-6 (Bevel type) Circlip 44-7 Housing 44-7R Right housing
44-7U Upper housing
44-7L Left (lower) housing
44-7K dowel pin
44-7B Bolt 44-8a Bearing 44-8b Bearing 44-9 Bevel type circlip 45 Cam phase control (accelerator) motor 45-2 Drive gear 45-3 Circlip 45-4 Bolt 45-5 O-ring 46 Idle gear 48 Needle bearing with cage 49 Thrust washer 51 Locking piece 51a Tip projection 51-2 Bolt 67 Pin 71 Phase sensor unit 72 Cam phase control (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 L Valve unit maximum outer circumference inclusion line

The valve lift arm portion 21 _EX b is formed in a comb shape near the left and right valve shafts in the swing axis direction from the swing shaft portions 21 _EX c _R and 21 _EX c _L provided to be divided into left and right in the axial direction. (Right valve lift arm portion 21 _EX b _R and left valve lift arm portion 21 _EX b _L ), adjusting screw boss 21 _EX d is provided at the tip near the valve stem shaft, and arms 21 _Ex e, 21 _Ex f The left and right valve lift arms and the left and right pivot shafts are connected to form a square arm. (See Figures 2-3, 4, and 6)
By using a B-shaped arm, the rigidity and strength are dramatically improved.
The right swing shaft portion 21 _EX c _R of the exhaust swing arm 21 _EX is disposed between the swing shaft portions 21 c _R and 21 c _L of the intake swing arm 21.
By arranging one swinging shaft part of the other swing arm between the split swinging shaft parts, the total swinging shaft part width when assembling the two swing arms is one swing arm swinging Since the width of the shaft and the width of the outer side surface of the two swing shafts of the other swing arm are added, the shim can be adjusted without being affected by the pitch crossing between the swing shafts. The flutter in the swing axis direction can be minimized.

The position of the intake swing arm 21 and the exhaust swing arm 21 _{EX in} the swing axis direction is fixed to the outer side of the exhaust swing arm left swing shaft portion 21 _EX c _L and the intake swing arm right swing shaft portion 21 c _R on both outer sides of the thrust washers 24. The circlip 26 or the rocker arm shaft 27 stepped portion 27a locked to the circlip groove of the horseshoe shim 25, the rocker arm shaft 27 is disposed on both outer sides thereof, and the thickness of the horseshoe shim 25 is adjusted to adjust the thickness of the swing shaft portion. In addition to adjusting the axial clearance, the position of the intake swing arm 21 in the swing axis direction is adjusted.
The horseshoe-shaped shim 25 is provided with a concave portion 25a in a part thereof, the tip protrusion 51a of the locking piece 51 is exposed to the concave portion 25a, and the locking piece 51 is fixed with a bolt 51-2 to prevent the shim from coming off and rotating.
Circlip 26 determines the phase at circlip phasing boss _1-5,2 LR _-2,2 LC -2 and locking pieces projecting end 51a provided on the cylinder head 1 and the lower cam shaft housing _{2 L} cam lobe, the accelerator Prevents contact with fork guide bearings. (See Figures 2-3, 7, and 8)
By adopting a roller swing arm as a valve lifter, the rigidity and reciprocating part weight are slightly disadvantageous compared to the direct hitting type, but the cam angle becomes lower and the inclination becomes weaker because of the lever ratio, so the change in operating angle can be increased, Since the cam is displaced from the upper side of the valve shaft, there is an advantage that the tappet clearance can be easily adjusted.
However, since the variation of the lift amount by the lever ratio is increased by using the roller swing arm, 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).
Since the shim has a horseshoe shape, it can be inserted with the roller swing arm assembled to the rocker arm shaft, so after the cylinder head is assembled to the cylinder, all the valve system parts are assembled and the head cover is not assembled. By this, the tuning (inter-cylinder lift amount adjustment) can be performed precisely and efficiently without re-disassembling the valve system parts.
Further, by fixing the position of the swing shaft in the swing shaft direction by shim adjustment in a state where the both swing shaft outer surfaces of the intake swing arm and one swing shaft portion of the exhaust swing arm are abutted and the clearance is eliminated, Both axial backlashes can be minimized. Precise output control becomes possible by suppressing variations in the intake side lift.

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 _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 3 Cylinder Head Cover 3-2 Cylinder Head Cover Gasket 3-3 Cylinder Head Cover Bolt 4 Accelerator Shaft Unit Cap 4-1 O-ring 10 Camshaft Unit 11 Camshaft 11 _G Pin Guide (Cam) Groove 11 _O Intake valve opening cam 11 _OG pin guide cam groove 11 _C Intake valve closing cam 11 _CG pin guide cam groove 11 _EX exhaust cam 11 _EXG guide pin engagement groove 11 _EXO exhaust valve opening cam 11 _EXOG pin guide (cam) groove 11 _EXC exhaust valve closing cam 11 _EXCG pin guide (cam) groove 12 intake cam lobe 13 circlip 14 key 15 driven sprocket 18 shim 20 intake rocker arm (swing arm) unit 21 intake rocker arm 21a camf Follower arm
(Swing arm) 21a _O valve open cam follower arm
21a _C valve closing cam follower arm
21b Valve lift arm
21b _R right valve lift arm
21b _L left valve lift arm
21c Oscillating shaft
21c _R right oscillating shaft
21c _L left swing shaft
21d Adjust screw boss
21e Connecting arm
21f Connecting arm 21-2 Pin 21-3 Needle bearing 21-4 Roller follower 20 _EX exhaust rocker arm (swing arm) unit 21 _EX exhaust rocker arm 21 _EX a cam follower arm
(Swing arm) 21 _EX a _O valve opening cam follower arm
21 _EX b Valve lift arm
21 _EX b _R Right valve lift arm
21 _EX b _C Middle valve lift arm
21 _EX b _L Left valve lift arm
21 _EX c Oscillating shaft
21 _EX c _R right swing shaft
21 _EX c _L Left swing shaft
21 _EX d Adjust screw boss
21 _EX e connecting arm 21 _EX- 2 pin 21 _EX f connecting arm 21 _EX- 3 needle bearing 21 _EX- 4 roller follower 22 adjusting screw 23 nut 24 thrust washer 25 horseshoe shim 25a recessed part 26 circlip 27 rocker arm shaft part 27a 27-2 plug 28 (bevel type) circlip 30 intake valve unit 31 intake valve 31a intake valve stem 30 _EX exhaust valve unit 31 _EX exhaust valve 31 _EX a exhaust valve stem 32 valve stem seal 33 locking piece (cotter)
34 (Lower) Retainer 34a Cylindrical guide 35 Set screw 36 Nut with flange 36a Stepped pocket 37 Shim 37a Retainer collar side contact surface
37b Stopper 38 Valve spring seat 38a Cylindrical guide 39 Valve spring 40 Cam phase control (accelerator) shaft unit 41 Cam phase control (accelerator) shaft 41 _G pin guide cam groove 41-2 Key 41-2a Rising part 41-3 Bolt 41 -4 Pin with flange 41-5 Bearing 41-6 Bevel type circlip 41-7 Nut 41-8 Guide pin 41-9 Guide roller 44 Cam phase control (accelerator) shaft Slide actuator unit 44-1 Male screw shaft 44-2 Joint bracket 44-3 Female thread boss 44-3a Spacer 44-4 Driven gear 44-5 Key 44-6 (Bevel type) Circlip 44-7 Housing 44-7 _R Right housing
44-7 _U upper housing
44-7 _L left (lower) housing
44-7 _K knock pin
44-7 _B bolt 44-8a Bearing 44-8b Bearing 44-9 Bevel type circlip 45 Cam phase control (accelerator) motor 45-2 Drive gear 45-3 Circlip 45-4 Bolt 45-5 O-ring 46 Idle gear 48 Needle bearing with cage 49 Thrust washer 51 Locking piece 51a Tip projection 51-2 Bolt 67 Pin 71 Phase sensor unit 72 Cam phase control (accelerator) shaft slide sensor 72-1 Bolt 72-2 O-ring 73 Detection arm 81 Ignition Plug hole tube (Injector hole tube)
82 O-ring L Valve unit maximum outer circumference inclusion line

The position of the intake swing arm 21 and the exhaust swing arm 21 _{EX in} the swing axis direction is fixed to the outer side of the exhaust swing arm left swing shaft portion 21 _{EX cL} and the intake swing arm right swing shaft portion 21 _cR. A horseshoe shim 25, a circlip 26 locked to a circlip groove of the rocker arm shaft 27 or a rocker arm shaft 27 stepped portion 27a are arranged on both outer sides, and the thickness of the horseshoe shim 25 is adjusted to adjust the axis of the oscillating shaft portion. While adjusting the direction clearance, the position of the intake swing arm 21 in the swing axis direction is adjusted.
The horseshoe-shaped shim 25 is provided with a concave portion 25a in a part thereof, the tip protrusion 51a of the locking piece 51 is exposed to the concave portion 25a, and the locking piece 51 is fixed with a bolt 51-2 to prevent the shim from coming off and rotating.
Circlip 26 determines the phase at circlip phasing boss _1-5,2 LR _-2,2 LC -2 provided in the cylinder head 1 and the lower cam shaft housing _{2 L} lobe, keys, contact with the flanged pin It is preventing.
(See Figures 2-3, 7, and 8)
By adopting a roller swing arm as a valve lifter, the rigidity and reciprocating part weight are slightly disadvantageous compared to the direct hitting type, but the cam angle becomes lower and the inclination becomes weaker because of the lever ratio, so the change in operating angle can be increased, Since the cam is displaced from the upper side of the valve shaft, there is an advantage that the tappet clearance can be easily adjusted.
However, since the variation of the lift amount by the lever ratio is increased by using the roller swing arm, 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).
Since the shim has a horseshoe shape, it can be inserted with the roller swing arm assembled to the rocker arm shaft, so after the cylinder head is assembled to the cylinder, all the valve system parts are assembled and the head cover is not assembled. By this, the tuning (inter-cylinder lift amount adjustment) can be performed precisely and efficiently without re-disassembling the valve system parts.
Further, by fixing the position of the swing shaft in the swing shaft direction by shim adjustment in a state where the both swing shaft outer surfaces of the intake swing arm and one swing shaft portion of the exhaust swing arm are abutted and the clearance is eliminated, Both axial backlashes can be minimized. Precise output control is possible because variations in intake-side lift can be suppressed.

Claims (9)

A pin guide cam groove in which the cam of a part of cams arranged in parallel on the same axis varies in phase, the camshaft is a double shaft, the pin is fixed to the inner shaft, and the phase changes in the axial direction to the outer shaft The cam with variable phase is fixed in the axial direction and is supported on the outer shaft so that it can rotate freely, and a groove for guiding the pin is provided in the shaft hole, and the phase of the cam is adjusted by sliding the inner shaft. Variable valve gear. 2. The valve gear according to claim 1, wherein the rotation direction of the phase fixing cam is fixed to the outer shaft with a key or the like, and the axial direction is fixed to the outer shaft with a circlip or the like along with the phase variable cam. . For all cams that are arranged in parallel on the same axis, the cam shaft is a double shaft, the pin is fixed to the inner shaft, and a groove that guides the pin parallel to the shaft is provided on the outer shaft. The cam with variable phase is fixed in the axial direction and supported on the outer shaft so that it can rotate freely. Also, a pin guide cam groove whose phase changes in the axial direction is provided in the shaft hole. A valve gear that varies the phase of the cam. 4. The valve gear according to claim 3, wherein the amount of phase change relative to the amount of axial movement of the pin guide cam groove is different for each cam. 4. The valve operating apparatus according to claim 3, wherein the suction and exhaust cams are arranged in parallel on the same axis, and the phase change direction of the pin guide cam groove of the cam shaft hole is reversed. 6. The valve operating apparatus according to claim 5, wherein the suction and exhaust overlaps are set small on the low rotation side, and the pin guide cam grooves are set so that the overlap increases as the rotation speed increases. Opening and closing with respect to camshaft shaft center The camshaft phase difference on the center of the roller follower at the end of the cam follower arm is set to about 1/2 of the phase difference on the crankshaft of the intake and exhaust lift curves, and suction and exhaust on the camshaft are set. 4. The valve gear according to claim 3, wherein the phases of the cam peaks are substantially matched. The camshaft is a double shaft, and the intake three-dimensional cam fixed to the inner shaft is fixed in the rotational direction and slid freely in the axial direction. The phase of the flat exhaust cam arranged on the exhaust flat cam can be rotated on the outer shaft, supported axially by a fixed axial direction, and the guide flat provided at right angles to the outer shaft. The pin that is locked in the rotational direction is fixed in the axial direction and the rotational direction is freely adjustable, and the pin guide cam groove provided in the inner shaft allows the valve to shift the phase of the exhaust flat cam by the pin by sliding the inner shaft. . The valve gear according to any one of claims 1 to 8, wherein a phase change amount with respect to an axial movement amount of the pin guide cam groove is changed.

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