JP2014077428A - Continuous stepless variable valve device with intake double cam shafts and 3d cams - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a variable valve mechanism having several intake valves per cylinder in which a lift amount, working angle, and timing are continuously variable and right/left lift difference and one valve rest can be attained.SOLUTION: There is provided a variable valve device comprising a cam lobe 12 having several intake valves 31 per cylinder, formed to cause a working angle and timing to be continuously changed, integrally rotated with a cam shaft 11 and axially and relatively movable in respect to the cam shaft, and a roller swing arm 21 pressed by a cam surface to cause the valves to be moved forward or rearward and a lift amount, working angle, and timing of the valves are controlled in a stepless and continuous variable manner in response to a running situation. Two intake cam shafts are arranged, a cam lobe and a roller swing arm are arranged for every intake valve to eliminate the above-mentioned problems, they are arranged at both sides divided in respect to an axis of a valve stem of the intake valve as viewed from an axial direction of the cam shafts, and an exhaust cam 12Ex is arranged at one cam shaft in parallel with the intake cam lobe to enable a compact cylinder head like DOHC to be attained.

Description

The present invention is an internal combustion engine in a two-wheeled vehicle or automobile, and has a plurality of intake valves, camshafts, and intake cam lobes per cylinder, and is formed so that the height, operating angle, and timing are continuously changed, and rotates integrally with the camshaft. In addition, it has a cam lobe that can move in the axial direction and a roller swing arm (rocker arm) that is pressed against the cam surface to move the valve forward and backward. The present invention relates to a valve operating device that performs continuously variable control in a stepless manner.

Patent Document 1, which has a plurality of intake valves per cylinder, has a swing cam provided for each valve and causes lost motion to continuously vary the lift amount, the working angle, and the timing, and allows a left-right lift difference and one-side valve rest. 2, 3 are disclosed.
JP-A-11-107725 JP 2003-12981 A Special table 2004-521234 gazette

In addition, a three-dimensional cam is formed side by side for each valve on a single camshaft, and by sliding the shaft, the lift amount, working angle, and timing can be continuously varied, and the patent allows a left-right lift difference and one-side valve rest. Documents 4 and 5 are disclosed.
Japanese Patent Publication No. 7-45803 JP 9-21305 A

Improvements to Patent Documents 1 to 3 have already been put into practical use, and they are based on the concept of US Pat. No. 3,261,338, using a rotating cam and a swinging reciprocating cam, or the center of a reciprocating cam or a rotating cam follower. By moving the position of the reciprocating cam, the reciprocating cam is lost to change the lift and the operating angle at the same time. By providing a swing cam for each valve, the left-right lift difference and one-side valve rest can be achieved. Becomes complicated and increases the weight and cost, and increases the weight of the reciprocating motion part, increases the mechanical loss due to the reduced rigidity, and makes it difficult to increase the rotation speed. In addition, VVT is necessary to obtain an appropriate opening / closing timing, and due to the slow response speed, the response improvement due to the abolition of the throttle valve is negated. Furthermore, since the lift amount is controlled by the lost motion, the lift curve in the low lift region is determined by the lift curve at the maximum lift, making it difficult to obtain the optimum lift curve for the desired output.

In order to improve these drawbacks, it has been proposed to form a three-dimensional cam for each valve on a single camshaft and integrally form it, and to slide the shaft. There are a direct hit type patent document 4 in which a tappet is slid in the valve stem axial direction, a swing arm type patent document 5 and the like. However, in the system that makes line contact with the cam and follows the change in the contact line angle, the cam crest shape in the cam shaft direction needs to be a straight line, and there is a large limit on cam crest shape setting, and the optimum lift curve for each cam crest height The timing and the amount of ramp cannot be set arbitrarily, and it is possible to make a difference between the left and right valve lifts. In order to achieve valve deactivation, the contact between the cam and the follower must be point contact, but even for point contact, multiple cams per cylinder are arranged on the same camshaft, and multiple intake valves are set separately. In the methods disclosed in Patent Documents 4 and 5, etc., the angle of the cam crest slope is increased, and the change amount of the valve lift relative to the cam slide amount, that is, the minimum unit change amount of the output is kept within the change amount required by the accelerator control. This is very difficult, especially for small displacement engines with short camshaft bearing spans. As a countermeasure, there has been proposed one in which a plurality of intake valves are lifted by one intake cam lobe, but the contact load between the outer peripheral spherical contact surface of the roller follower that contacts the cam lobe and the three-dimensional contact surface of the cam lobe is about 2 In order to keep the contact Hertz stress within the allowable range, the lift curve must be more gradual than the direct hitting engine with a flat cam and bottomed cylindrical tappet, and the opening time area can be reduced to obtain the same output. It was compensated by expanding the working angle, resulting in an increase in pumping loss.
Further, in all of Patent Documents 1 to 5, since the lift amount control of the left and right intake valves is performed by one control device, the left and right valve lift difference is fixed to a fixed value.

The present invention has been made in view of the above-described problems, and has a plurality of intake valves per cylinder, is formed so that the height, working angle, and timing are continuously changed, and rotates integrally with the camshaft. In addition, it has a cam lobe that can move in the axial direction and a roller swing arm (rocker arm) that is pressed against the cam surface to move the valve forward and backward. In a valve gear that continuously controls in stages, two intake camshafts are provided, and a cam lobe and a roller swing arm (rocker arm) are provided for each intake valve. Map control of the difference between the left and right valve lifts with respect to the rest, engine speed and torque maps, and camshaft When viewed from the camshaft axis direction, the cylinder head is placed directly on both sides with respect to the valve stem axis line of the intake valve and the exhaust cam is arranged on one camshaft along the intake cam lobe so that the cylinder head is directly hit. It is made compact like DOHC, and the response difference is made zero by changing the phase of the slide of the intake cam lobe and the exhaust cam with the same accelerator shaft. After assembling the cylinder head to the cylinder, assemble all the valve system parts and cover the head. It is an object of the present invention to enable accurate and efficient implementation of tappet clearance and synchronization (adjustment of the lift amount between cylinders) without re-disassembling the valve system parts up to the state before assembly.

In order to solve the above-mentioned problems, the invention of claim 1 has a plurality of intake valves per cylinder, and the height, working angle, and timing are continuously changed on the cam surface inclined in the camshaft axial direction. A cam lobe that rotates integrally with the camshaft and is relatively movable in the axial direction, and a roller swing arm (rocker arm) that makes point contact with the cam surface and presses and moves the valve back and forth, depending on the accelerator opening and travel conditions In a valve operating system that controls the valve lift, operating angle, and timing continuously and continuously by sliding the cam lobe in the camshaft axial direction, there are two intake camshafts. An arm (rocker arm) is provided.
By providing an intake cam lobe and a roller swing arm (rocker arm) for each left and right intake valve, the outer spherical contact surface of the roller follower of the roller swing arm (rocker arm) compared to when the left and right intake valves are lifted by a single intake cam lobe The contact load between the cam lobe and the three-dimensional contact surface of the cam lobe is approximately halved, and a lift curve (opening time area) similar to that of a direct hitting type using a flat cam and a bottomed cylindrical tappet can be achieved. As a result, pumping loss can be reduced, and by providing a camshaft for each intake cam lobe, the intake cam lobe and slide length can be increased compared to the case where the intake cams are arranged side by side on the same axis, and the valve lift height increases the operating angle. Even if the phase is greatly changed or the phase at the time of maximum lift is greatly shifted, the cam mountain slope is moderated. In addition, since the amount of change in valve lift (opening time area) relative to the amount of cam lobe slide, that is, the amount of change in output can be reduced, the minimum unit change amount that can be controlled by accelerator control can be set small, and more precise output control becomes possible. .

The invention of claim 2 is characterized in that, in the invention of claim 1, the cam lobe provided for each intake valve is formed with a different cam mountain shape, and the lift characteristics of the intake valves on the left and right of the cylinder are made different. To do.
By setting a large difference between the left and right intake valve lifts on the low rotation side, that is, the low lift side, where the flow velocity of the intake air is low and the swirl flow tends to be weak, the combustion speed increases and the output and fuel consumption improve. By setting a small difference between the left and right intake valve lifts on the high rotation side, that is, on the high lift side, where the flow velocity is high and the swirl flow is strong, the operating angle to obtain the same output can be narrowed, pumping loss can be reduced, and suction by reducing suction resistance The output can be improved by increasing the amount of air.
Even in the lost motion type, it is possible to make a difference in the lift characteristics of the intake valves on the left and right of the cylinder by providing a swing cam for each valve, but the lift curve is set by the rotating cam and the swing type reciprocating cam. Because the lift curve in the intermediate lift range is determined by the lift curve at the maximum lift, there is no degree of freedom, and by setting the lift curve at the maximum lift to the same left and right, increasing the intake amount in the maximum output range and aiming to improve output In addition, it becomes almost impossible to freely change the lift characteristics of the left and right valves in the intermediate lift region. For example, it is not possible to set the lift curve for the maximum lift to be the same on the left and right sides, to make the operating angle and timing the same with an intermediate lift with a lift difference, or to simultaneously make the valve closing timing with a lift and valve opening timing difference. It's possible. It is necessary to employ a point contact follower even if three-dimensional cams are arranged side by side for each valve.

The invention of claim 3 is characterized in that, in the inventions of claims 1 and 2, the plurality of intake camshafts are arranged on both sides with respect to the valve stem axis of the intake valve as viewed from the camshaft axial direction. And
By arranging both intake camshafts away from the upper extension line of the adjustment screw shaft of the intake swing arm (rocker arm), turn the adjustment screw with the box type driver on the inner shaft and Adjustable screw adjustment and tightening tool can be passed through the intake camshaft or intake cam lobe while fixing at the tappet clearance phase and tightening and locking the nut with a cylindrical box type wrench on the outside of the coaxial) The tappet clearance can be adjusted precisely and efficiently without reassembling the valve system parts in a state before assembling all the valve system parts and assembling the head cover.

According to a fourth aspect of the present invention, in the first, second, and third aspects of the invention, the plurality of rocker arm shafts corresponding to the plurality of intake camshafts and cam lobes are viewed from the camshaft axial direction, and the valve stem axis line of the intake valve In this case, the camshaft is arranged on both sides and on the cylinder head mating surface side (lower side) with respect to the camshaft.
Since the outer diameter of the swinging shaft part of the roller swing arm (rocker arm) is smaller than the maximum rotation outer circumference locus of the intake cam lobe and exhaust cam, the suction and exhaust valve shaft V bank angle can be narrowed, and a compact combustion chamber can be achieved. Further, the inclination angle of the intake port with respect to the cylinder axis can be reduced, the intake efficiency can be improved and the combustion efficiency can be improved by enhancing the intake tumble flow, and the intake and exhaust directions of the cylinder head can be made compact.

The invention of claim 5 is characterized in that, in the invention of claim 4, the axial centers of the plurality of rocker arm shafts are the mating surfaces of the cylinder head and the lower camshaft housing.
By using the rocker arm shaft axis center as the mating surface of the cylinder head and lower camshaft housing, the lower camshaft housing can be assembled without tightening the rocker armshaft without radial clearance, and swinging of the swing arm can be suppressed and the valve lift accordingly. Since the variation in the amount becomes small, more accurate intake air amount control can be performed.
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.

According to a sixth aspect of the present invention, in the fourth and fifth aspects of the present invention, the axial centers of the plurality of intake camshafts are used as the mating surfaces of the upper and lower camshaft housings, together with the mating surfaces of the cylinder head and the lower camshaft housing. It is characterized by being parallel to the head mating surface.
By making all the mating surfaces parallel to the cylinder head mating surface, machining is facilitated and accuracy is improved.

According to a seventh aspect of the present invention, in the first to sixth aspects of the present invention, an exhaust cam is disposed on the camshaft disposed in the intake and exhaust valve stem shaft V bank alongside the intake cam lobe.
A camshaft for the exhaust cam is provided separately from the plurality of intake camshafts, and the exhaust cam is a three-dimensional cam lobe formed so that the lift amount, operating angle, and timing are continuously changed on the cam surface inclined in the camshaft axis direction, By sliding it, the maximum performance can be obtained if the lift amount, working angle, and timing are continuously variable by interlocking or independent control with a plurality of intake cam lobes. The cylinder head width in the intake and exhaust directions is greatly increased.
By providing an exhaust cam on one intake camshaft, the exhaust camshaft can be eliminated, the cost and weight can be reduced by reducing the number of iron parts, and the cylinder head width in the intake and exhaust directions can be reduced. The exhaust cam is a three-dimensional cam, and the lift amount, operating angle, and timing cannot be continuously varied, but the phase can be varied by using a flat cam.

The invention of claim 8 is characterized in that, in the invention of claim 7, the phase of the exhaust cam is variable.
With variable exhaust cam phase, only the exhaust valve timing can be changed, and the lift amount and operating angle cannot be changed. However, the lift amount, operating angle, and timing of the exhaust lift curve required between low output and high output are not possible. Since the difference is small, especially the difference in lift amount and working angle is small, if the timing can be varied, performance comparable to that when a three-dimensional cam is adopted also on the exhaust side can be obtained. In this embodiment, the phase of the exhaust flat cam with respect to the intake three-dimensional cam is determined by the pin guide cam groove, so that it can be accurately varied with zero response delay, and if the cam lobe slide drive device breaks down, its slide position Even if it stops at, or even if it shifts to a different slide position, since the phase of the opposing cam is set by the pin guide cam groove, the adverse effect can be reduced. Also, 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 like a curve, a polygonal line, etc. It is possible to freely adjust the exhaust timing according to the timing of the intake three-dimensional cam.

Further, in the ninth aspect of the present invention, in the seventh aspect of the present invention, the axial slide range of the intake cam lobe arranged on the camshaft outside the intake and exhaust valve stem shaft V bank is arranged on the camshaft in the V bank. It is characterized by being longer than the intake cam lobe.
By providing a non-lift region in the elongated portion, one-side valve can be stopped.

According to a tenth aspect of the present invention, in the seventh aspect of the present invention, the intake cam lobe on the side where the exhaust cams are arranged side by side lifts the intake valve on the side away from the exhaust cam in the camshaft axial direction. The intake cam lob disposed on the camshaft lifts the intake valve on the side close to the exhaust cam.
The axial position of the roller follower of the roller swing arm (rocker arm) is approximately the middle position of the span obtained by adding the slide length to the axial length of the cam lobe, so the axial position of the roller follower on the side without the exhaust cam is The axial position of the roller follower on the side where the exhaust cam is located is shifted to the cam lobe side by about half the axial length of the exhaust cam. Therefore, by lifting the intake valve on the side away from the exhaust cam in the camshaft axial direction, that is, on the side close to the intake cam lobe, with the intake cam lobe on the side with the exhaust cam, the length of the valve lift arm of the roller swing arm (rocker arm) Similarly, by lifting the intake valve on the side close to the exhaust cam with the intake cam lobe on the side without the exhaust cam, the length of the valve lift arm of the roller swing arm can be shortened, and the weight of the reciprocating motion part can be reduced. Light weight and high rigidity.

According to an eleventh aspect of the present invention, in the seventh and ninth aspects of the present invention, a plurality of intake cam lobes are slid by a single accelerator motor, and a reduction ratio ( It is characterized in that the number of rotations is changed by providing a speed increasing ratio) and the amount of slide is changed.
There is also a method to change the slide amount of the male threaded shaft as a method of changing the slide amount, but this corresponds to the difference in the slide length ratio of the first and second intake cam lobes depending on the displacement, that is, the cylinder diameter and the exhaust cam width. The male screw shaft and the female screw boss part, in which the lead is changed little by little, are prepared, which is not realistic. By dealing with the gear ratio, the male screw shaft and the female screw boss can be made common and the cost is reduced.

According to a twelfth aspect of the present invention, in the second, seventh, ninth, and eleventh aspects of the present invention, a zero lift region is formed in the intake cam lobe disposed on the camshaft outside the intake and exhaust valve stem shaft V bank, and the one-side valve is stopped. It is possible to make it possible.
Compared with the case where a lift difference is provided between the left and right valves, the inflow speed and the strength of the swirl flow are further increased, so that the combustion speed is increased and the output and fuel consumption can be improved.

The invention of claim 13 is characterized in that, in the invention of claim 1, a cam lobe slide drive device is provided for each camshaft, and the slide of the intake cam lobe can be independently controlled for each camshaft.
In general, by setting a large difference between the left and right intake valve lifts on the low speed side where the flow rate of intake air is low and the swirl flow tends to be weak, combustion speed increases, output and fuel consumption improve, and intake air By setting the difference between the left and right intake valve lifts to be small on the high rotation side where the flow velocity is high and the swirl flow is strong, the operating angle to obtain the same output can be narrowed and the pumping loss can be reduced. The output can be improved by the increase. However, even in the same rotation, there is a difference in valve lift difference that provides the best performance on the low torque side and the high torque side.
If independent control is not used, the difference between the left and right intake valve lifts is determined by the lift height.However, by independently controlling the left and right intake valve lifts arbitrarily, the map rotation speed and torque maps can be used for map coordinate conditions. Map control that gives the optimal difference between the left and right valve lifts can be realized, further improving output and fuel consumption.

It has a plurality of intake valves per cylinder, is formed so that the height, working angle, and timing change continuously, rotates together with the camshaft and is axially movable, and is pressed against the cam surface Roller swing arm (rocker arm) that moves the valve forward and backward, and in the valve train that continuously and variably controls the valve lift, operating angle, and timing according to the accelerator opening and travel conditions, the outer spherical contact surface of the roller follower In order to keep the amount of change in the valve lift with respect to the cam lobe slide amount, that is, the amount of change in the output within the change amount required by the accelerator control, while keeping the contact angle between the cam lobe and the cam lobe within the roller follower width, There is a limit to setting a large value, and multiple cam lobes per cylinder are arranged on the same camshaft, and multiple intake valves are installed. Because it is difficult to lift each one, as a countermeasure, multiple intake valves are lifted with one cam lobe, so that the contact hertz stress between the outer spherical contact surface of the roller follower and the cam lobe falls within an allowable range. In addition, in order to make the lift curve gentle, the intake valve opening time area is reduced, and in order to make the same time area, the operating angle must be increased, and the pumping loss is increased accordingly. In addition, it is difficult to make a lift difference between the left and right valves, and it is very difficult to arbitrarily make a left / right difference or to stop the valve.
The present invention solves these problems and devise the arrangement of the camshaft, cam, roller swing arm (rocker arm), etc., so that the cylinder head can be made as compact as direct DOHC.

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

The valve operating apparatus according to the first embodiment is a specific example of claims 1 to 12, and has a plurality of intake valves per cylinder, and has two intake camshafts, and a three-dimensional cam lobe and a roller for each intake valve. A swing arm (rocker arm) is provided, and the camshaft and rocker arm shaft are divided and arranged on both sides of the valve stem axis of the intake valve when viewed from the camshaft axis direction. (Lower side) The exhaust cam is a flat cam, and the intake and exhaust valve stem shafts are arranged on the same camshaft alongside the intake cam lobe, and the intake cam lobe is on the maximum lift side. It is arranged on the sliding side, and is the intake camshaft unit 10, the intake and exhaust camshaft units Including Tsu DOO _{10 IN,} and _EX, the intake swing arm unit 20, intake, exhaust the swing arm unit _{20 IN,} and _EX, the intake valve unit 30, an exhaust valve unit _{30 EX.} The first accelerator shaft unit 40 is arranged coaxially with the camshaft arranged outside the intake and exhaust valve stem shaft V bank, and slides the intake cam lobe according to the accelerator opening and the traveling state, and the intake and exhaust valve stem shaft V bank. It includes a second accelerator shaft unit _{40IN, EX} that is disposed coaxially with the camshaft disposed therein and that slides the intake cam lobe and varies the exhaust cam phase in accordance with the accelerator opening and the traveling state. (See Figures 1-1 to 4 and 7)
By providing an intake cam lobe and a roller swing arm (rocker arm) for each left and right intake valve, the outer spherical contact surface of the roller follower of the roller swing arm (rocker arm) compared to when the left and right intake valves are lifted by a single intake cam lobe The contact load between the cam lobe and the three-dimensional contact surface of the cam lobe is approximately halved, and a lift curve (opening time area) similar to that of a direct hitting type using a flat cam and a bottomed cylindrical tappet can be achieved. As a result, pumping loss can be reduced, and by providing a camshaft for each intake cam lobe, the intake cam lobe and slide length can be increased compared to the case where the intake cams are arranged side by side on the same axis, and the valve lift height increases the operating angle. Even if it is changed greatly or the phase of the lift curve apex is greatly shifted, the cam crest slope is relaxed. The amount of change in the valve lift (opening time area) relative to the cam lobe slide amount, that is, the amount of change in output can be reduced, so that the minimum unit change amount that can be controlled by the accelerator control can be set small and more precise output control is possible. It becomes.
In addition, by placing both intake camshafts away from the upper extension line of the adjustment screw shaft of the intake swing arm (rocker arm), the box type (adjustable screw can be turned with the box driver of the inner shaft) The screw can be passed through the space between the intake camshaft or the intake cam lobe by adjusting the adjustment screw and tightening the nut with the cylindrical box type wrench on the outside of the coaxial shaft. Therefore, the tappet clearance adjustment can be carried out precisely and efficiently without reassembling the valve system parts in a state before assembling all the valve system parts and assembling the head cover.
In addition, the outer diameter of the swinging shaft of the roller swing arm (rocker arm) is smaller than the maximum rotation outer peripheral locus of the intake cam lobe and exhaust cam, so the intake and exhaust valve shaft V-bank angle can be narrowed, resulting in a compact combustion chamber. In addition, the intake port inclination angle with respect to the cylinder axis can be reduced, the intake efficiency and the combustion efficiency can be improved by enhancing the intake tumble flow, and the intake and exhaust directions of the cylinder head can be made compact.
In addition, the exhaust cam camshaft is provided separately from the plurality of intake camshafts, and the exhaust cam is a three-dimensional cam lobe formed so that the lift amount, operating angle, and timing continuously change on the cam surface inclined in the camshaft axial direction. The maximum performance can be obtained by sliding, and the lift amount, working angle, and timing can be continuously varied by interlocking or independent control with a plurality of intake cam lobes. However, three camshafts are required, resulting in an increase in cost and weight. At the same time, the cylinder head width in the intake and exhaust directions will increase significantly, but by installing an exhaust cam on one intake camshaft, the exhaust camshaft can be abolished, and the cost of reducing iron parts can be reduced. The weight can be reduced and the cylinder head width in the intake and exhaust directions can be reduced.
The exhaust cam is a three-dimensional cam, and the lift amount, operating angle, and timing cannot be continuously varied, but the phase can be varied by using a flat cam.

The intake camshaft unit 10, together with the first accelerator shaft unit 40 arranged coaxially, as seen from the direction parallel to the camshaft shaft, is a suction, exhaust camshaft unit 10 _{IN, EX ,} together with the second accelerator shaft units 40 _{IN and EX} arranged on the same axis, is parallel to the cylinder head alignment surface near the center of the cylinder axis in the intake and exhaust valve stem axis V bank as viewed from the direction parallel to the camshaft axis. The upper and lower camshaft housings 2U and 2L are used as the mating surfaces.
(See FIG. 1-2).
Since the camshaft 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 Figures 1-7 and 2-5)

In the intake camshaft unit 10 and the suction and exhaust camshaft units 10 _{IN and EX} , the intake camshaft 11 and the suction and exhaust camshafts 11 _{IN and EX} are rotatably supported by the lower camshaft housing 2L and the upper camshaft housing 2U. Is done. The intake camshaft 11 and the intake and exhaust camshafts 11 _{IN, EX} have a phase corresponding to the ignition timing of each cylinder for each cylinder, and the keys 41-of the first accelerator shaft 41 and the second accelerator shaft 41 _{IN, EX} . The first intake cam lobe 12 and the second intake air that are fixed to the first accelerator shaft 41 and the second accelerator shaft 41 _{IN, EX} via the key 41-2 are provided. The slide is guided while regulating the phase of the cam lobe relative to the cam shaft of the cam lobe 12 _IN .
The first intake cam lobe 12 and the second intake cam lobe 12 _IN are three-dimensional cams formed such that the height, the operating angle, and the timing are continuously changed on the cam surface inclined in the camshaft axial direction. The operating angle is set to be increased and the timing can be changed. Therefore, as shown in FIGS. 1-1 and 7, the cam crest on the slide direction side is low, and the cam crest is gradually formed higher as it goes to the opposite side in the slide direction. On the opposite side of the sliding direction, the rising portion 41-2a of the key 41-2 is sandwiched between the flange of the flanged pin 41-4 and the first intake cam lobe 12 and the second intake cam lobe 12 _IN end face without axial clearance. 1 press-fitted flanged pin 41-4 in bore of the intake cam lobe 12 and the second intake cam lobe _{12 iN,} suppress axial play of the first intake cam lobe 12 and the second intake cam lobe _{12 iN} for the key 41-2 minimized In addition, minute clearances are provided in the phase direction and the radial direction.
Note that fine adjustment of the axial position of the second intake cam lobe 12 _IN with respect to the first intake cam lobe 12 in the reference cylinder shifts the meshing of the first driven gear 44-4 and the second driven gear 44 _{IN, EX-} 4. To do. For example, if the lead of the male screw shaft 44-1 is 3 mm and the number of teeth of the second driven gears 44 _{IN and EX-} 4 is 30, it can be adjusted in steps of 0.1 mm every time the teeth are shifted. Sufficient adjustment accuracy.
First, after adjusting the axial displacement of the second intake cam lobe 12 _IN to the first intake cam lobe 12 in the reference cylinder to the minimum, the thickness of the horseshoe shim 25 is adjusted to adjust the swing axial position of each swing arm. The lift height between cylinders is tuned by finely adjusting. (See Figures 1-1, 2, 7, 2-5)
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 12 _EX is axially fixed to the side where the second intake cam lobe 12 _IN is slid to the maximum lift side by a circlip 13 at a phase corresponding to the ignition timing of each cylinder for each cylinder. at intake, exhaust camshaft _{11 iN,} is supported by a _EX, the shaft hole portion provided with a guide pin engaging grooves _{12 EX G} to engage in the rotation direction fixed to the head of the guide pin 41-8 Yes. Further, the base circle diameter of the exhaust cam 12 _EX is set larger than the base circle diameter of the second intake cam lobe 12 _IN .
Guide pins 41-8 are intake, exhaust camshaft _{11 IN,} pin guide grooves _{11 IN} drilled in the direction of rotation _EX, axially fixed at _{EX G,} it is swinging rotatably disposed.
(See Figures 1-1, 2 and 7)
When the second intake cam lobe slides to the maximum lift side, the cam peak of the second intake cam lobe on the side close to the exhaust cam becomes the low lift side cam peak, so the second intake cam lobe is low on the cam follower arm portion of the exhaust swing arm. Even if it overlaps the roller boss bearing pin boss part in the camshaft axial direction, it is difficult to make contact, so the slide amount of the second intake cam lobe can be increased by that much, and the inclination of the cam crest can be reduced, and more precise lift control becomes possible. .
Further, by setting the base circle diameter of the exhaust cam larger than that of the second intake cam lobe, the cam follower arm roller of the exhaust swing arm can be set even if the cam height on the low lift side of the second intake cam lobe is set higher. Even if it overlaps the follower bearing pin boss part in the camshaft axial direction, it is difficult to make contact, and the outer shape of the roller follower bearing pin boss part of the cam follower arm part can be made closer to the roller follower diameter, so that strength and rigidity can be improved.

Since the first intake cam lobe 12 provided on the intake camshaft 11 outside the intake and exhaust valve stem shaft V bank has a long slide range due to the absence of the exhaust cam, the cam lobe distributing the slide extender, in the sliding direction of the extended cam lobe to form a free lift zone, a cam top of the lift zone also different from the second intake cam lobe 12 _iN shape than the sliding length of the second intake cam lobe 12 _iN By sliding the first accelerator shaft 41 so that the slide length becomes longer by the extension, as shown in FIGS. 1-13 and 14, the lift amount and the lift curve of the left and right valves are made different, and the one-side valve is stopped. Realized.
Figure 1-13 is first intake cam lobe 12 and the sliding range of the second intake cam lobe 12 _IN the horizontal axis shows the lift height of the cam crest apex on the vertical axis. The horizontal axis indicates the ratio of the slide amount to the slide range of each cam lobe. The actual slide amounts of the first intake cam lobe 12 and the second intake cam lobe 12 _IN at the same horizontal axis position are different, but the lift height at the same position is different. Indicates the lift height at the top of the cam crest of the other intake cam lobe with respect to the lift height at the top of the cam crest of one intake cam lobe. The ruled line 1 indicates the lift height of the cam peak of each cam lobe when the minimum lift is performed, and the ruled line 6 indicates the lift height of the cam peak of each cam lobe. The lift curve at the time of ruled lines 1-6 is shown in FIG. 1-14. On the intake side, the solid line is the right, and the dotted line is the lift curve of the left intake valve. (See Figures 1-1, 2, 7, 2-5)
Setting a large difference between the left and right intake valve lifts on the low rotation side, that is, the low lift side, where the flow velocity of the intake air is low and the swirl flow tends to be weak, increases the combustion speed and improves the output, fuel consumption, and the flow rate of the intake air High swirl flow and high rotation side, that is, high and low lift side, by setting the left and right intake valve lift difference small, the working angle to obtain the same output can be narrowed and the pumping loss can be reduced, and the intake air amount by reducing the suction resistance The output can be improved by increasing.
Furthermore, by stopping the valve on one side, the inflow speed and the strength of the swirl flow are increased more than when a lift difference is provided between the left and right valves, thereby increasing the combustion speed and improving the output and fuel consumption.
Even in the lost motion type, it is possible to make a difference in the lift characteristics of the intake valves on the left and right of the cylinder by providing a swing cam for each valve, but the lift curve is set by the rotating cam and the swing type reciprocating cam. Because the lift curve in the intermediate lift range is determined by the lift curve at the maximum lift, there is no degree of freedom, and by setting the lift curve at the maximum lift to the same left and right, increasing the intake amount in the maximum output range and aiming to improve output In addition, it becomes almost impossible to freely change the lift characteristics of the left and right valves in the intermediate lift region. For example, it is not possible to set the lift curve for the maximum lift to be the same on the left and right sides, to make the operating angle and timing the same with an intermediate lift with a lift difference, or to simultaneously make the valve closing timing with a lift and valve opening timing difference. It's possible. It is necessary to employ a point contact follower even if three-dimensional cams are arranged side by side for each valve.

The intake driven sprocket 15 and the suction and exhaust driven sprockets 15 _{IN and EX} are press-fitted and fixed to one end of the intake camshaft 11 and the suction and exhaust camshafts 11 _{IN and EX} , and the flanges provided on the end surfaces of the driven sprocket and the camshaft. The camshaft housing is axially fixed and rotatably supported. Pins 67, which are cam phase detection sensor protrusions, are press-fitted and fixed to the intake and exhaust driven sprockets 15 _{IN and EX} bosses. The phase sensor unit 71 detects the phase and controls the ignition timing with the output signal. Yes.
The cam chain is properly driven by a chain guide, chain tensioner, chain adjuster, etc., between the intake driven sprocket 15 and the intake and exhaust driven sprockets 15 _{IN, EX} and a drive sprocket formed at one end of a crankshaft (not shown). It is wound and mounted. (See Figures 1-1 and 2)

As shown in FIG. 1-2, the intake swing arm unit 20 and the suction and exhaust swing arm units 20 _{IN and EX} are arranged on the cylinder head mating surface side with respect to the intake cam shaft unit 10 and the suction and exhaust cam shaft units 10 _{IN and EX} ( Viewed from the direction parallel to the camshaft shaft on the lower side, sucks the intake swing arm unit 20, sucks the exhaust valve stem shaft V bank outside, sucks the exhaust swing arm unit _{20IN, EX} , and exhaust valve stem shaft V A swing axis is disposed in the bank near the center of the cylinder axis in parallel with the cylinder head mating surface, and the cylinder center 1 and the lower camshaft housing 2 are centered on the intake rocker arm shaft 27 and the intake and exhaust rocker arm shafts 27 _{IN and EX. L is} the mating surface.
By using the rocker arm shaft axis center as the mating surface of the cylinder head and lower camshaft housing, the lower camshaft housing can be assembled without tightening the rocker armshaft without radial clearance, and swinging of the swing arm can be suppressed and the valve lift accordingly. Since the variation in the amount becomes small, more accurate intake air amount control can be performed.
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.
Further, by making all the mating surfaces parallel to the cylinder head mating surface, the processing is facilitated and the accuracy is improved.

As shown in FIG. 1-4, the first intake swing arm 21 is rotatably supported by a pin 21-2 press-fitted and fixed to the tip portion via a needle bearing 21-3. A cam follower arm portion 21a having a roller follower 21-4 that is in contact is integrally formed in a comb shape from the vicinity of the center of the swing shaft portion 21c in the axial direction, and the stem top portion of the intake valve unit 30 closer to the exhaust cam than one side thereof. A valve lift arm 21b that pushes the valve through an adjusting screw 22 to advance and retract the valve is integrally formed so as to protrude in an L shape when viewed from a direction perpendicular to the camshaft shaft, and is adjusted at the tip near the valve stem shaft. A so-called roller provided with a screw boss 21d and pivotally supported on an intake rocker arm shaft 27 arranged in parallel with the camshaft shaft. In swingarm, the axial center of the intake rocker arm shaft 27 is disposed substantially within the stroke range of the stem top with the valve axis. (See Figures 1-2 and 4)
Similarly, as shown in FIG. 1-5, the second intake swing arm _21IN is rotatably supported by a pin _21IN- 2 that is press-fitted and fixed to the tip portion via a needle bearing _21IN- 3. The cam follower arm portion 21 _IN a having a roller follower 21 _IN- 4 that makes point contact with the two intake cam lobes 12 _IN is divided into left and right in the axial direction, and is provided with a swing shaft portion 21 _{IN cR} connected by a connecting arm 21 _IN f. 21 _{IN cL} is integrally formed in a comb-like shape, and the stem top portion of the intake valve unit 30 on the side farther from the exhaust cam as viewed from the direction perpendicular to the camshaft shaft is extended so as to extend from one of them. the pressed valve lift arm 21 iN _b for advancing and retracting the valve through, viewed from a direction parallel to the cam shaft axis, and integrally formed in a T-shape, Balbus The tip of the near arm shaft provided with adjusting screw boss 21 IN _d, intake disposed parallel to the camshaft axis, an exhaust rocker arm shaft 27 _IN, so-called roller swing arm that is swingably supported on the _EX (rocker arm) Thus, the shaft centers of the suction and exhaust rocker arm shafts 27 _{IN and EX} are arranged within the approximate stroke range of the stem top surface in the valve shaft direction.
The first intake swing arm 21 is provided with a shaft portion of a roller follower that contacts the cam lobe in a valve lift arm portion between the swing shaft portion and the valve pressing portion as viewed from the direction parallel to the camshaft shaft. Even if the valve lift arm ratio is brought close to 1, even if the swing shaft is rotated around the camshaft shaft and brought close to the valve stem shaft, the roller follower shaft only shifts to the position where it overlaps the valve pressing portion. Although it can be said that complete swing arm type, the second intake swing arm 21 _iN, the axis of the roller follower in contact with the cam lobe has become a distance T-shaped arm from the valve lift arm. In this embodiment, since the valve lift arm ratio is about 1.5, the shaft portion of the roller follower is close to the valve lift arm portion when viewed from the direction parallel to the camshaft shaft, and from the valve lift arm portion to the cam follower arm. The part is extended to make a T-shaped arm, but if the valve lift arm ratio is made closer to 1, the swing shaft part is rotated around the camshaft axis and brought closer to the valve stem axis. Since the arm and the valve pressing part are separated from each other, each arm is separately extended from the swing shaft part into a V-shape, which is not a complete rocker arm in the form of a balance, but the roller follower shaft and valve pressing part Since it can be said to be a rocker arm type deformation with a swing shaft portion between them, it is described as a roller swing arm (rocker arm).
(See Figures 1-2 and 3)
The axial position of the roller follower of the roller swing arm (rocker arm) is approximately the middle position of the span obtained by adding the slide length to the axial length of the cam lobe, so the axial position of the roller follower on the side without the exhaust cam is The axial position of the roller follower on the side where the exhaust cam is located is shifted to the cam lobe side by about half the axial length of the exhaust cam. Therefore, by lifting the intake valve on the side away from the exhaust cam in the camshaft axial direction, that is, on the side close to the intake cam lobe, with the intake cam lobe on the side with the exhaust cam, the length of the valve lift arm of the roller swing arm (rocker arm) Similarly, by lifting the intake valve on the side close to the exhaust cam with the intake cam lobe on the side without the exhaust cam, the length of the valve lift arm of the roller swing arm can be shortened, and the weight of the reciprocating motion part can be reduced. Light weight and high rigidity.
Further, in the second intake swing arm, the two swing arm swinging shafts for lifting the valve can have a long span, so that the flutter is suppressed and the fluctuation of the contact position between the three-dimensional cam and the roller follower and the flutter of the valve lift curve are suppressed. And the variation in opening time area 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 an essential condition to suppress variations in the lift amount (opening time area).

Roller followers 21-4 and 21 _IN -4 have an outer cross-sectional shape that requires countermeasures against fretting corrosion that occurs when there is no lift. The maximum outer diameter is R, where R is the camshaft unit and swing (rocker) arm unit. It is set to the maximum R that can absorb the alignment error, and 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 1-15)
In this embodiment, the drop amount d from the maximum outer diameter at both ends A ′ and B ′ of the maximum R portion (cam base circle cylindrical surface contact portion when there is no lift) width L is calculated by the following formula. The center C of the maximum R section width L is the maximum outer diameter, the R connecting the points A ′, B ′ and C is set to the maximum R, and the center of the roller follower shaft at the point B ′ is the center of the maximum outer diameter. Is a shape connected by a quadratic curve toward the contact point D (the contact end during lift) on the cam mountain maximum inclination angle α on R ′.
(Solid line in Fig. 1-15)
d = (Axis direction 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 rocker arm shaft + Axis direction tilt of the roller follower with respect to the swing shaft hole of the roller swing arm (rocker 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 surface as shown by the two-dot chain line in Fig. 1-15. 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 produced. However, if the swing arm type is used, the alignment is fixed and there is almost no function to absorb the alignment error. Since it hits only at both ends A and B of the 15 cylindrical surface and becomes point contact, the amount of wear increases. In particular, wear at point B causes fluctuations in the valve lift amount, so a countermeasure is required. (Each bearing clearance and needle bearing crowning absorbs alignment errors, but the effect is small.) By adopting this plan, alignment errors can be absorbed, but they are all-point contact and not line contact when there is no lift.
However, since the surface pressure can be made close to line contact with a large R, fretting corrosion wear when there is no lift can be prevented, and the change in curvature at the B point can be reduced, so that wear at the B point can also be prevented.

As shown in FIG. 1-6, the exhaust swing arm 21 _EX is rotatably supported by a pin 21 _EX- 2 that is press-fitted and fixed to the tip portion via a needle bearing 21 _EX- 3, and is connected to the exhaust cam 12 _EX . a cam follower arm _{21 EX} a having a roller follower ₂₁ EX -4 contacting, the valve lift arm _{21 EX} b to the stem top of the exhaust valve unit _{30 EX} forward and backward the pressed valve via the adjusting screw 22, the cam shaft axis And a so-called roller swing arm (rocker arm) that is integrally formed in a T shape and is pivotally supported on the intake and exhaust rocker arm shafts 27 _{IN and EX} , which are arranged in parallel with the camshaft shaft. , intake, the axial center of the exhaust rocker arm shaft 27 _{iN, EX} stands straw stem top surface in the valve axis direction It is disposed within the range. (See Fig. 1-2)
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 cR} and 21 _{EX cL} provided separately in the left and right directions in the axial direction (right The valve lift arm portion 21 _EX b _R and the left valve lift arm portion 21 _EX b _L ), and an adjusting screw boss 21 _EX d is provided at the tip near the valve stem shaft, and the connecting arms 21 _Ex e and 21 _EX f are used. Connected to form a square arm. (See Figures 1-3 and 6)
The right swing shaft portion 21 _{EX cR} of the exhaust swing arm 21 _EX is disposed between the swing shaft portions 21 _{IN cR} and 21 _{IN cL} of the second intake swing arm 21 _IN .
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 first intake swing arm 21 and the second intake swing arm 21 _IN and the exhaust swing arm 21 _{EX in} the swing axis direction is fixed at both ends of the swing shaft portion 21 _C in the first intake swing arm 21. In the arm 21 _IN and the exhaust swing arm 21 _EX , the exhaust swing arm left swinging shaft portion 21 _{EX cL} and the second air swing arm right swinging shaft portion 21 _{IN cR} are both outside the thrust washer 24 and the horseshoe shim 25 on both outsides. Intake rocker arm shaft 27 or suction, exhaust rocker arm shaft 27 _IN, circlip 26 or intake rocker arm shaft 27 locked in circlip groove of _EX , suction, exhaust rocker arm shaft 27 _{IN, EX} stepped portions 27a, _27IN, By arranging _EX a and adjusting the thickness of the horseshoe shim 25, the axial direction of the oscillating shaft part The lift height between the cylinders is synchronized by adjusting the clearance and adjusting the position of the first intake swing arm 21 and the second intake swing arm _{21IN in} the swing axis direction.
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 determining circlip phase provided in the cylinder head 1 and the lower cam shaft housing _{2 L} boss _1-5,2 LR _-2,2 LC -2 beauty locking piece projecting end 51a cam lobe, the accelerator Prevents contact with fork guide bearings.
The locking piece 51 has the same symbol although the shape and size differ depending on the place of use.
(See Figures 1-3, 4, 8, and 9)
Adopting a roller swing arm (rocker arm) as a valve lifter is slightly disadvantageous in terms of rigidity and reciprocating part weight in comparison with the direct hitting type. However, the cam angle is lowered and the inclination is weakened by the lever ratio. In addition, the cam is displaced from the upper side of the valve shaft, so that the tappet clearance can be easily adjusted.
However, since the variation of the lift amount corresponding to the lever ratio is increased by using the roller swing arm (rocker 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).
By making the shim into a horseshoe shape, it can be inserted with the roller swing arm (rocker arm) assembled to the rocker arm shaft. After assembling the cylinder head to the cylinder, assemble all valve parts and assemble the head cover. By the previous state, tuning (cylinder lift amount adjustment) can be performed precisely and efficiently without re-disassembling the valve operating system parts.
Also, the position of the swing shaft in the swing shaft direction is fixed by shim adjustment with the two swing shaft outer surfaces of the second air swing arm and the one swing shaft portion of the exhaust swing arm butted away from each other. Thus, the backlash in both axial directions can be minimized. Precise output control becomes possible by suppressing variations in the intake side lift.

The intake rocker arm shaft 27 and the intake and exhaust rocker arm shafts 27 _{IN and EX} are clamped and clamped in bearing holes provided in the cylinder head 1 and the lower camshaft housing 2 _L without radial clearance, and the first accelerator shaft slide actuator unit 44 and second axle shaft slide actuator unit _{44 iN,} housing 44-7 stepped portion 27a is provided in the vicinity of the mounting and _{27 iN} of _{EX, EX} a cylinder head 1 and the lower cam without axial clearance in the bevel shaped circlip 28 It is assembled to the shaft housing 2 _L. (See Figures 1-2, 3, and 4)
The intake rocker arm shaft 27 and the intake and exhaust rocker arm shafts 27 _{IN and EX} have a hollow structure, and both ends are plugged with plugs 27-2 to form a lubricating oil path, and the lubricating oil formed in the cylinder head and camshaft housing. With the oil supplied through the road, the intake camshaft 11 and the intake and exhaust camshafts 11 _{IN and EX} bearings, the swing shaft 21 c of the first intake swing arm 21 and the swing of the second intake swing arm 21 _IN The shaft portion 21 _IN c and the swing shaft portion 21 _EX c of the exhaust swing arm 21 _EX are lubricated, and the needle bearings 21-3, 21 _IN- 3, 21 _EX- 3, the cam crest portion, the roller follower 21-4, Oil jet injection lubrication is applied to 21 _IN -4 and 21 _EX -4.
(See Figures 1-3, 4, 7, 2-5)

As shown in FIG. 1-2, the intake valve unit 30 includes two intake valves 31 _R and 31 _{L in} which intake valve stems 31 _Ra and 31 _La are guided by intake valve guides 1-3 _R and 1-3 _L. Prepare.
When the intake valves 31 _R and 31 _L are lifted, air that is guided from an air cleaner and an intake pipe (not shown) via the intake port 1 _{IN and} whose flow rate is mainly controlled by the valve lift amount, intake passage, or combustion An air-fuel mixture with fuel sprayed from an injector (not shown) is introduced into each chamber.

The intake valves 31 _R and 31 _L have a conical split cotter 33 locked to a cotter groove near the top of the valve stems 31 _Ra and 31 _La. engaging the retainer 34 is provided with a cylindrical guide 34a, a cylindrical guide 34a and the valve spring seat between the valve guide _1-3 R, 1-3 _L press-part upper of the valve spring seat 38 of the cylinder head 1 A valve spring 39 of a coil spring guided by 38 cylindrical guides 38a is accommodated, and is assembled to the cylinder head 1 so as to freely advance and retract. (See Fig. 1-2)

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

The first accelerator shaft unit 40 and the second accelerator shaft unit 40 _{IN, EX} are arranged in the center holes of the intake camshaft unit 10 and the intake and exhaust camshaft units 10 _{IN, EX} and are supported so as to be slidable in the axial direction.
In the first accelerator shaft 41 and the second accelerator shaft 41 _{IN, EX} , a key 41-2 is inserted into a key groove carved at a phase corresponding to the ignition timing of each cylinder for each cylinder, and a bolt 41-3 is inserted. It is fixed at. The first intake cam lobe 12 fixed to the first accelerator shaft 41 and the second intake cam lobe 12 _IN fixed to the second accelerator shaft 41 _{IN, EX} via the key 41-2 are connected to the intake cam shaft 11 and the intake and exhaust air. The key 41-2 is guided by a keyway that slides and guides the key 41-2 provided in the camshafts 11IN and _EX in the axial direction, and slides while the phase with respect to the camshaft is regulated.
On the exhaust cam 12 _EX side of the second accelerator shaft 41 _{IN, EX} , on the _EX side, a pin guide cam groove whose phase is varied by sliding the second accelerator shaft 41 _{IN, EX} through a guide roller 41-9 through a guide roller 41-9. 41 _{IN and EX G} are carved, and the cam groove makes it possible to freely change the amount of phase change with respect to the accelerator shaft slide amount (the amount of axial movement of the pin guide cam groove), such as a polygonal line or a curved line. . (See Figures 1-1, 2, 7, 12, 2-5)
With variable exhaust cam phase, only the exhaust valve timing can be changed, and the lift amount and operating angle cannot be changed. However, the lift amount, operating angle, and timing of the exhaust lift curve required between low output and high output are not possible. Since the difference is small, especially the difference in lift amount and working angle is small, if the timing can be varied, performance comparable to that when a three-dimensional cam is adopted also on the exhaust side can be obtained. In this embodiment, the phase of the exhaust flat cam with respect to the intake three-dimensional cam is determined by the pin guide cam groove, so that it can be accurately varied with zero response delay, and if the cam lobe slide drive device breaks down, its slide position Even if it stops at, or even if it shifts to a different slide position, since the phase of the opposing cam is set by the pin guide cam groove, the adverse effect can be reduced. Also, 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 like a curve, a polygonal line, etc. It is possible to freely adjust the exhaust timing according to 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 grooves 41 _{IN and EX G} have a shape (see FIG. 1-12) that is optimally overlapped with each intake lift curve. 1-1 and FIG. 1-12, the pin guide cam grooves 41 _{IN, EX G} shown in the right figure have the exhaust lift curve shown in FIG. 1-14, and the pin guide cam grooves 41 _{IN, EX G} as shown in the left figure are shown. If the shape is adopted, the angle can be further advanced from the solid lift curve of the exhaust lift curve of FIG. 1-14 in the middle lift region, and the overlap can be reduced.
(See Figures 1-13 and 14)
Further, a bearing 41-5 is inserted into the stepped shaft portion at one end of the first accelerator shaft 41 and the second accelerator shaft 41IN _{, EX} , and the inner race is fixed by the bevel-shaped circlip 41-6 without axial backlash. ing.
The outer race of the bearing 41-5 is press-fitted and fixed to the male screw shaft 44-1 of the first accelerator shaft slide actuator unit 44 and the second accelerator shaft slide actuator unit 44IN _{, EX} , and the male screw shaft 44-1 is rotated. The first joint bracket 44-2 and the second joint bracket 44IN _{, EX-} 2 that guide the slide while being regulated are press-fitted and fixed. The second joint bracket 44 _{IN, EX-} 2 is provided with a groove for engaging the tip of the detection arm 73 of the accelerator shaft slide sensor 72, and the amount of slide of the second accelerator shaft 41 _{IN, EX} is determined by the phase of the detection arm 73. The accelerator motor 45 is controlled by detecting the change.
(See Figures 1-1, 2, 7, and 10)
If the sliding range of the first accelerator shaft 41 and the second accelerator shaft 41 _{IN, EX} is the same, the first joint bracket 44-2 and the second joint bracket 44 _{IN, EX-} 2 are integrated, and one is located near the center. Two accelerator shaft slide actuator units are provided and can be controlled by the accelerator motor 45. However, in order to change the slide range of the first accelerator shaft 41 and the second accelerator shaft 41 _{IN, EX} , two accelerator shaft slide actuator units are provided. Provided.

The first accelerator shaft slide actuator unit 44 and the second accelerator shaft slide actuator unit 44 _{IN, EX} are fixed to the cylinder head 1 by a housing 44-7, and a key 44-5 and a circlip 44- 6, the first driven gear 44-4 and the second driven gear 44IN _{, EX-} 4 are fixed. 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 fixed to the cylinder head 1 by the knock pin 44-7 is positioned at _K volts 44-7 _B in split type. In this embodiment, a ball screw type is used to reduce mechanical loss, but a trapezoidal screw may be adopted.
When the first accelerator shaft slide actuator unit 44 and the second accelerator shaft slide actuator unit 44 _{IN, EX} are linked, the driving force of the accelerator motor 45 is changed from the second driven gear 44 _{IN, EX} -4 via the accelerator shaft idle gear 46i. The speed increase ratio inversely proportional to the length of the sliding range of the first intake cam lobe and the second intake cam lobe (because the accelerator motor 45 is arranged on the second driven gear 44 _{IN, EX} -4 side, Since the sliding range of the first intake cam lobe is longer than that of the second intake cam lobe with the exhaust cam, the rotation needs to be increased and the speed is increased relative to the second driven gear.The accelerator motor 45 is arranged on the first driven gear 44-4 side. The second driven gear is decelerated relative to the first driven gear. )
The accelerator shaft idle gear 46i is fixed to the accelerator shaft idle gear shaft 47i, which is fixed with zero gap with the two split surfaces of the housing 44-7 as an axis, and is axially fixed and rotatable via a needle bearing 48i with a cage. It is supported.
If the number of teeth of the first driven gear 44-4 and the second driven gear 44IN _{, EX-} 4 is increased and directly engaged, the accelerator shaft idle gear 46i and related parts can be eliminated, but the male screw shaft 44-1 and the female screw boss 44 When -3 is commonly used, the sliding direction of the first accelerator shaft 41 is opposite to the second accelerator shaft 41 _{IN, EX} . If the first intake cam lobe 12 is inverted in the phase direction and is inverted in the axial direction and arranged on the exhaust cam side, this can be dealt with and the cost can be reduced, but the gear rotation inertia increases and the slide response speed related to the accelerator shaft unit. In this embodiment, the idle gear is provided to reduce the inertia and improve the response speed.
A drive gear 45-2 fixed by a spline and a circlip 45-3 sucks into an output shaft of an accelerator motor 45 fixed to the cylinder head 1, and a needle bearing 48 with a retainer on the exhaust rocker arm shaft 27IN _{, EX} axis. Rotation of the output shaft of the accelerator motor 45 corresponding to the accelerator opening and the traveling state is brought into mesh with the second driven gears 44 _{IN and EX-} 4 via the accelerator motor idle gear 46 rotatably supported by the first accelerator shaft. 41 and the second accelerator shaft 41 _{IN, EX} , that is, the sliding motion of the first intake cam lobe 12 and the second intake cam lobe 12 _IN . (See Figures 1-1, 7, and 11)
The cam lobe slide drive device is a combination of the first accelerator shaft slide actuator unit 44 and the second accelerator shaft slide actuator unit 44 _{IN, EX} and the accelerator motor 45.

An ignition plug hole tube (injector hole tube) 81 is inserted into a hole formed in the cylinder head 1 and the cylinder head cover 3 and sealed with an O-ring 82 to form an ignition plug hole (injector hole) 1 _IG. exhaust substantially parallel to the exhaust valve axis in the valve unit 30 _EX side, it is disposed in the valve lift arm formed in shaped Hollow exhaust swing arm 21 _EX. (See Figures 1-1 and 2)

The valve operating apparatus of the second embodiment is a specific example of claim 13, whereas the valve operating apparatus of the first embodiment performs slide control by interlocking a plurality of accelerator shafts with one accelerator motor. An accelerator motor is provided for each shaft and independent slide control is performed. The intake camshaft unit 10, the intake and exhaust camshaft units 10 _{IN and EX} , the intake swing arm unit 20, the intake and exhaust swing arm units 20 _{IN and EX} , The intake valve unit 30, the exhaust valve unit 30 _EX , and the second accelerator shaft unit 40 _{IN and EX} are the same as in the first embodiment, so the description is omitted, and the first accelerator shaft unit 40 to which an accelerator motor is added is described in the first embodiment. The contents of the change will be described.

In the first axle shaft unit 40, changes to the first embodiment other than the accelerator motor additional portion engages the first detecting arm 73 _IN distal end of the first axle shaft slide sensor 72 _IN to the first joint bracket 44-2 groove is added to the amount of sliding of the first axle shaft 41 controls the accelerator motor 45 detected by the phase change of the first detection arm 73 _iN, abolished the accelerator shaft idle gear 46i, the first driven gear 44-4 Is common to the second driven gears 44 _{IN and EX-} 4.
The relationship between the accelerator motor 45 and the accelerator motor idle gear 46 is the same as in the first embodiment, and a description thereof will be omitted.
The first detection arm 73 _IN has an arm length longer than that of the second detection arm 73 and the first accelerator shaft slide sensor 72 by the extent that the slide range of the first accelerator shaft 41 is extended with _respect to the second accelerator shafts 41 _{IN and EX. By} using the effective detection range of _IN to the maximum and within the allowable detection range, precise and accurate slide control is achieved.
The first accelerator shaft slide sensor 72 _IN is obtained by reversing the direction of rotation detected by the second accelerator shaft slide sensor 72. However, if the value to be detected is read in reverse by the control software, it can be shared. (See Figures 2-1 to 5)
In general, by setting a large difference between the left and right intake valve lifts on the low speed side where the flow rate of intake air is low and the swirl flow tends to be weak, combustion speed increases, output and fuel consumption improve, and intake air By setting the difference between the left and right intake valve lifts to be small on the high rotation side where the flow velocity is high and the swirl flow is strong, the operating angle to obtain the same output can be narrowed and the pumping loss can be reduced. The output can be improved by the increase. However, even in the same rotation, there is a difference in valve lift difference that provides the best performance on the low torque side and the high torque side.
If independent control is not used, the difference between the left and right intake valve lifts is determined by the lift height.However, by independently controlling the left and right intake valve lifts arbitrarily, the map rotation speed and torque maps can be used for map coordinate conditions. Map control that gives the optimal difference between the left and right valve lifts can be realized, further improving output and fuel consumption.

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 DD line | wire of FIGS. 1-2. It is sectional drawing which follows the EE line of FIGS. 1-2. It is sectional drawing which follows the FF line of FIGS. 1-2. It is sectional drawing which follows the GG line of FIGS. 1-2. FIG. 4 is a developed sectional view taken along line HH in FIG. 1-3. FIG. 4 is a developed sectional view taken along line JJ in FIG. It is sectional drawing which follows the KK line | wire of FIGS. 1-1. It is sectional drawing which follows the LL line of FIGS. 1-1. FIG. 8 is a developed sectional view taken along line MM in FIG. 1-7. It is a figure which shows the left-right valve lift height with respect to a cam movement amount ratio. It is a valve lift curve figure. FIG. 4 is a detailed cross-sectional view of an intake roller follower.

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 equivalent to sectional drawing which follows the BB line of FIGS. 1-1 in 2nd embodiment. It is sectional drawing which follows the CC line of FIGS. It is sectional drawing which follows the DD line | wire of FIGS. It is sectional drawing which follows the EE line of FIGS.

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 _R Right Intake Valve Guide 1-3 _L Left Intake Valve Guide 1-3 _EX Exhaust Valve Guide 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 3-4 Cylinder head cover seal washer 4 Accelerator shaft unit cap 4-1 O-ring 10 Intake camshaft unit 11 Intake Camshaft 10 _{IN, EX} suction, exhaust camshaft unit 11 _{IN, EX} suction, exhaust camshaft 11 _{IN, EXG} pin guide groove 12 First intake cam lobe 12 _IN Second intake cam lobe 12 _EX exhaust cam 12 _EXG guide pin engagement groove 13 circlip 15 intake driven sprocket 15 _{IN, EX} intake, exhaust driven sprocket 20 intake swing arm unit 21 first intake swing arm 21a cam follower arm
21b Valve lift arm
21c Oscillating shaft
21d Adjust screw boss 21-2 Pin 21-3 Needle bearing 21-4 Roller follower 20 _{IN, EX} suction, exhaust swing arm unit 21 _IN Second intake swing arm 21 _IN a Cam follower arm
21 _IN b Valve lift arm
21 _IN c Oscillating shaft
21 _IN c _R right swing shaft
21 _IN c _L Left swing shaft
21 _IN d Adjust screw boss
21 _IN f connecting arm 21 _IN -2 pin 21 _IN- 3 needle bearing 21 _IN- 4 roller follower 21 _EX exhaust swing arm 21 _EX a cam follower arm
21 _EX b Valve lift arm
21 _EX b _R Right 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 f connecting arm 21 _EX- 2 pin 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 intake rocker arm shaft 27a stepped part 27 _IN Intake and exhaust rocker arm shaft 27 _{IN, EX} a Stepped portion 27-2 Plug 28 Bevel-type circlip 30 Intake valve unit 31 _R Right intake valve 31 _R a Right intake valve stem 31 _L Left intake valve 31 _L a Left intake valve stem 30 _EX exhaust valve unit 31 _EX exhaust valve 31 _EX a exhaust valve stem 32 valve stem seal 33 cotter 34 retainer 34a cylindrical guide 38 the valve spring seat 38a cylindrical guide 39 Lube spring 40 first accelerator shaft unit _{40 IN, EX} second accelerator shaft unit 41 first axle shaft 41 _{IN, EX} second axle shafts 41 _{IN, EX G} pin guide cam groove 41-2 key 41-2a rising portion 41- 3 Bolt 41-4 Pin with flange 41-5 Bearing 41-6 Bevel type circlip 41-8 Guide pin 41-9 Guide roller 44 First accelerator shaft slide actuator unit 44 _{IN, EX} Second accelerator shaft slide actuator unit 44- DESCRIPTION OF SYMBOLS 1 Male thread shaft 44-2 1st joint bracket 44 _{IN, EX-} 2 2nd joint bracket 44-3 Female thread boss | hub part 44-3a Spacer 44-4 1st driven gear 44 _{IN, EX-} 4 2nd driven gear 44-5 key 44-6 circlip 44-7 housing 44-7 _U upper housing
44-7 _L lower housing
44-7 _K knock pin
44-7 _B bolt 44-8a Bearing 44-8b Bearing 44-9 Bevel type circlip 45 Accel motor 45-2 Drive gear 45-3 Circlip 45-4 Bolt 45-5 O-ring 46 Accel motor idle gear 46i Accelerator shaft Idle gear 47i Accelerator shaft Idle gear shaft 48 Needle bearing with cage 48i Needle bearing with cage 49 Thrust washer 51 Locking piece 51a Tip protrusion 51-2 Bolt 67 Pin 71 Phase sensor unit 72 (Second) Accelerator shaft slide sensor 72 _IN first accelerator shaft slide sensor 72-1 volts 72-2 O-ring 73 (second) detecting arm 73 _IN first detection arm 81 spark plug hole tube (injector e Ruchubu)
82 O-ring

The position of the first intake swing arm 21 and the second intake swing arm 21 _IN and the exhaust swing arm 21 _{EX in} the swing axis direction is fixed at both ends of the swing shaft portion 21 _C in the first intake swing arm 21. In the arm 21 _IN and the exhaust swing arm 21 _EX , the exhaust swing arm left swing shaft portion 21 _{EX cL} and the second intake swing arm right swing shaft portion 21 _{IN cR} are both on the outer side of the thrust washer 24 and on both outer sides of the horseshoe shim 25. Intake rocker arm shaft 27 or suction, exhaust rocker arm shaft 27 _IN, circlip 26 or intake rocker arm shaft 27 locked in circlip groove of _EX , suction, exhaust rocker arm shaft 27 _{IN, EX} stepped portions 27a, _27IN, By arranging _EX a and adjusting the thickness of the horseshoe shim 25, By adjusting the directional clearance and adjusting the position of the first intake swing arm 21 and the second intake swing arm 21 _{IN in} the swing axis direction, the lift height between the cylinders is synchronized.
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.
The locking piece 51 has the same symbol although the shape and size differ depending on the place of use.
(See Figures 1-3, 4, 8, and 9)
Adopting a roller swing arm (rocker arm) as a valve lifter is slightly disadvantageous in terms of rigidity and reciprocating part weight in comparison with the direct hitting type. However, the cam angle is lowered and the inclination is weakened by the lever ratio. In addition, the cam is displaced from the upper side of the valve shaft, so that the tappet clearance can be easily adjusted.
However, since the variation of the lift amount corresponding to the lever ratio is increased by using the roller swing arm (rocker 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).
By making the shim into a horseshoe shape, it can be inserted with the roller swing arm (rocker arm) assembled to the rocker arm shaft. After assembling the cylinder head to the cylinder, assemble all valve parts and assemble the head cover. By the previous state, tuning (cylinder lift amount adjustment) can be performed precisely and efficiently without re-disassembling the valve operating system parts.
Further, the position of the swinging shaft in the swinging shaft direction is fixed in a shim-like manner with the outer surface of both swinging shafts of the second intake swing arm and the one-side swinging shaft portion of the exhaust swing arm butted with no gap. Thus, the backlash in both axial directions can be minimized. Precise output control is possible because variations in intake-side lift can be suppressed.

Claims (13)

With multiple intake valves per cylinder, the height, working angle, and timing are formed so as to continuously change on the cam surface inclined in the camshaft axial direction, and can rotate integrally with the camshaft and move in the axial direction The cam lobe and a roller swing arm (rocker arm) that makes point contact with the cam surface and is pressed to advance and retreat the valve, and slide the cam lobe in the camshaft axial direction according to the accelerator opening and travel conditions. In a valve operating apparatus that continuously and variably controls the amount, working angle, and timing in a stepless manner, the valve operating apparatus has two intake camshafts and is provided with a cam lobe and a roller swing arm (rocker arm) for each intake valve. 2. The valve operating apparatus according to claim 1, wherein the cam lobes provided for each intake valve are formed in different cam crest shapes, and the lift characteristics of the intake valves on the left and right sides of the cylinder are differentiated. The valve operating apparatus according to claim 1 or 2, wherein a plurality of intake camshafts are arranged on both sides with respect to a valve stem axis of the intake valve as viewed from the camshaft axial direction. Multiple rocker arm shafts corresponding to multiple intake camshafts and cam lobes are distributed to both sides with respect to the valve stem axis of the intake valve when viewed from the camshaft axial direction, and the cylinder head mating surface side (lower side) with respect to the camshaft The valve operating apparatus according to claim 1, 2, or 3 disposed in the above. The valve gear according to claim 4, wherein the shaft centers of the plurality of rocker arm shafts are used as mating surfaces of the cylinder head and the lower camshaft housing. 6. The valve operating apparatus according to claim 4, wherein the plurality of intake camshafts have an axial center as a mating surface of the upper and lower camshaft housings, and are parallel to the cylinder head mating surface together with the mating surfaces of the cylinder head and the lower camshaft housing. . The valve operating device according to claim 1, wherein an exhaust cam is disposed side by side with an intake cam lobe on a camshaft disposed in the intake and exhaust valve stem shaft V bank. The valve gear according to claim 7, wherein the phase of the exhaust cam is variable. 8. The valve operating apparatus according to claim 7, wherein an axial sliding range of the intake cam lobe arranged on the camshaft outside the intake and exhaust valve stem shaft V bank is longer than that of the intake cam lobe arranged on the camshaft in the V bank. Lift the intake valve on the side away from the exhaust cam in the camshaft axial direction with the intake cam lobe on the side where the exhaust cams are arranged side by side, and close to the exhaust cam on the intake cam lobe located on the camshaft outside the V bank The valve operating apparatus according to claim 7, wherein the intake valve is lifted. In a case where a plurality of intake cam lobes are slid by a single accelerator motor, a reduction ratio (speed increase ratio) is provided in the driving force transmission gear train between the accelerator shaft slide actuators to change the rotation speed and the amount of slide. Item 10. The valve gear according to Item 7 or 9. The valve operating device according to claim 2, 7, 9, or 11, wherein a zero lift region is formed in an intake cam lobe disposed on a cam shaft outside the intake and exhaust valve stem shaft V bank to enable one-side valve rest. The valve operating apparatus according to claim 1, wherein a cam lobe slide drive device is provided for each camshaft, and the slide of the intake cam lobe can be independently controlled for each camshaft.

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