JP2011111937A - Variable valve device of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a variable valve device of an internal combustion engine which enhances resistance to misalignment of an assembly cam for making a phase variable with a simple structure. <P>SOLUTION: The variable valve device includes a shaft member 14 with an assembly cam in which an assembly cam 22a having a cam face 22c is assembled and a camshaft member 13 having a fixed cam 12 formed integrally therewith aside from the shaft member 14. The cam face 22c of the assembly cam 22a is formed with a cam width dimension larger than a cam width c of a cam face 12a of the fixed cam 12. The constitution can keep favorable a contact state with a cam abutting face 9a of a sliding member 9 such as a tappet by the cam face 22c of the enlarged assembly cam 22a. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a variable valve operating apparatus for an internal combustion engine that includes a shaft member with an assembly cam to which an assembly cam that drives an intake valve or a pair of exhaust valves is assembled.

In a reciprocating engine (internal combustion engine) mounted on an automobile, a variable valve gear is being mounted on a cylinder head in order to prevent engine exhaust gas and improve pumping loss.
The variable valve operating system has a structure in which a phase between the valves of a multi-valve (a pair of intake valves and a pair of exhaust valves) widely used in an engine is varied to change a period during which the multi-valve is open. .

  This variable valve operating device is difficult to realize with a camshaft in which a fixed cam is integrally formed with a normal shaft. For this reason, in an engine having a plurality of camshafts (camshaft members) driven by crank output on the intake / exhaust side, the intake valve or Of the camshafts that drive the exhaust valves, the camshafts that require variable phase can be adjusted using a cam member with an assembled cam that is assembled with a separate cam. For a camshaft that does not perform the cam phase, a normal camshaft member in which a fixed cam is integrally formed is used.

  If further described, the shaft member with an assembly cam in Patent Documents 1 and 2 follows the arrangement of a pair of intake valves (or a pair of exhaust valves) for each cylinder, and a reference that forms a reference phase outside the shaft member. A structure is used in which the fixed cam is fixed and the assembled cam having the same cam width is assembled so as to be displaceable in the circumferential direction. The phase of the assembly cam is changed with reference to the reference fixed cam by the cam phase change mechanism, and the cam displacement of the reference fixed cam and the assembly cam is changed through the driven member of the tappet member (or rocker member, etc.) The period during which the pair of intake valves (or the pair of exhaust valves) is open is greatly changed.

JP 2009-144521 A JP 2009-144522 A

By the way, an assembly camshaft member is different from a camshaft member in which a normal fixed cam is integrally formed, and an assembly cam as a separate part is assembled to the shaft. Has a small clearance required for the variable operation of the assembly cam.
However, this clearance causes misalignment of the cam surface of the assembly cam. For this reason, the cam width end portion of the assembly cam may come into contact with a cam contact portion such as a tappet or a rocker. This causes an increase in friction and uneven wear. Moreover, due to misalignment, instability of the clearance is generated, and an offset load acting between the assembly cam and the shaft is increased, resulting in deterioration of responsiveness due to increased friction and wear of the part.

  Further, in a general camshaft in which a fixed cam is integrally fixed to the shaft, when the cam journal is provided between a pair of cams, the cam is used when both cams have substantially the same valve lift and timing. Misalignment does not increase because the valve lift load is applied evenly to the journal width, but if the camshaft with a built-in cam is used to shift the phase of the reference fixed cam and the built-in cam with a variable valve system, the cam journal Further misalignment occurs because the valve lift load works with a time difference before and after in the width direction. This misalignment is because the cam surface of the reference fixed cam and assembly cam reduces the contact area with the cam contact part of the tappet or rocker, and the load becomes high and the good lubrication state cannot be maintained. Increase and uneven wear.

When such a thing occurs, the variable valve mechanism varies in variable performance. For this reason, it is conceivable to employ misalignment processing, improve assembly accuracy, and use highly wear-resistant materials and surface treatment that can withstand misalignment, but both are expensive and require alternative technologies. .
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a variable valve operating apparatus for an internal combustion engine that has a simple structure and can increase the resistance against misalignment of an assembly cam that varies the phase.

In order to achieve the above-mentioned object, the invention according to claim 1 is a camshaft member in which a fixed cam is integrally formed separately from a shaft member with an assembled cam assembled with an assembled cam and the shaft member. The cam surface of the assembly cam is formed with a cam width dimension larger than the cam width of the cam surface of the fixed cam.
The invention according to claim 2 is a structure in which a reference fixed cam that drives any one of a plurality of intake valves or exhaust valves is formed integrally with a shaft member with an assembly cam separately from the assembly cam. The cam surface of the reference fixed cam is formed with a cam width dimension larger than the cam width of the cam surface of the fixed cam formed integrally with the cam shaft member.

  According to a third aspect of the present invention, the cam surface of the assembly cam is formed with a cam width dimension larger than the cam width of the cam surface of the reference fixed cam.

According to the first aspect of the present invention, the contact area with the tappet or the rocker cam contact portion due to misalignment of the cam surface of the assembly cam is maintained, a good lubrication state is maintained, and an increase in friction and uneven wear are caused. It is suppressed.
Therefore, with a simple structure, it is possible to increase the resistance against misalignment of the assembled cam that varies the phase.

According to the second aspect of the present invention, it is possible to increase the resistance against the misalignment of the cam surface of the reference fixed cam that forms the reference of the cam phase of the assembled cam.
According to the third aspect of the present invention, the reference fixed cam and the assembly cam have optimum cam widths, can effectively cope with misalignment associated with variable splitting, and are effective in reducing responsiveness and uneven wear due to increased friction. Can be suppressed.

1 is a plan view of an internal combustion engine equipped with a variable valve gear according to a first embodiment of the present invention. Sectional drawing of the variable valve apparatus which follows the II line | wire in FIG. Sectional drawing which shows the cam shaft in which the cam was integrally formed. The disassembled perspective view which shows the structure of each part of a variable valve apparatus. The diagram which shows the variable characteristic of a variable valve apparatus. The figure for demonstrating the difference in the contact state of the cam and tappet which the change of a cam width brings. The top view which shows the principal part of the 2nd Embodiment of this invention.

Hereinafter, the present invention will be described based on a first embodiment shown in FIGS.
FIG. 1 shows a plan view of an internal combustion engine, for example, a multi-cylinder reciprocating engine (hereinafter simply referred to as an engine), and FIG. 2 shows a cross section taken along line I-I in FIG. The cylinder block 2 is a cylinder head mounted on the head of the cylinder block 1.

Among these, the cylinder block 1 is formed with a plurality of cylinders 3 (only some cylinders are shown) along the longitudinal direction of the engine as shown in FIGS. In each cylinder 3, each piston 4 separated from a crankshaft (not shown) via a connecting rod (not shown) is housed so as to be able to reciprocate.
A combustion chamber 5 is formed on the lower surface of the cylinder head 2 corresponding to each cylinder 3. Each combustion chamber 5 has a pair of intake ports 7 (two) for performing intake and a pair of exhaust ports (not shown) for performing exhaust. Each intake port 7 is provided with a pair of intake valves 10 (two) each having a bottomed cylindrical tappet 9 (driven member) attached to the stem end. A spherical crowning (cam contact surface) formed on the top surface 9 a of each tappet 9 faces the upper portion of the cylinder head 2. Each exhaust port (not shown) is similarly provided with a pair of exhaust valves (both not shown) with tappets. Similarly, the valve base end faces the upper part of the cylinder head 2. The intake port 7 and the exhaust port (not shown) are opened and closed by the intake valve 10 and the exhaust valve (not shown). Each combustion chamber 5 is provided with a spark plug (not shown).

  In addition, on the upper left and right sides of the cylinder head 2, there are provided an intake side valve operating device 6a and an exhaust side valve operating device 6b which are driven by the shaft output of the crankshaft. The valve gear 6a has a camshaft 14 for intake, and the valve gear 6b has a camshaft 13 for exhaust (all of which correspond to a plurality of shaft members of the present application). By using this, a predetermined combustion cycle (four cycles of intake stroke, compression stroke, expansion stroke, and exhaust stroke) is repeatedly performed in each cylinder 3. Of the valve gears 6a and 6b, the exhaust-side valve gear 6b uses, for example, a structure using a normal camshaft 13 shown in FIG. Specifically, a camshaft member in which an exhaust cam that is a fixed cam is integrally formed, specifically, a camshaft 13 that is formed together with a shaft 13a by cutting out the exhaust cams 12 for a plurality of cylinders is used. The camshaft 13 is assembled so as to be rotatable in the direction in which the cylinders 3 are arranged, and the cam surface 12a of each exhaust cam 12 is brought into contact with the crowning (not shown) of the top surface of the tappet. Thus, the cam displacement of each exhaust cam 12 is transmitted to an exhaust valve (not shown).

  Unlike the exhaust-side camshaft 13, the camshaft 14 of the intake-side valve gear 6a is configured by assembling a separate assembly cam having a cam surface as shown in FIG. A member, a camshaft having a so-called assembly cam structure is used. The camshaft 14 is used to form a split type variable valve operating device 15 as shown in FIG.

  That is, the camshaft 14 has an inner camshaft 17b formed of a solid shaft member serving as a control member in an outer camshaft 17a formed of a pipe member as shown in FIGS. 2 and 4, for example. It is formed of a double shaft 17 that is rotatably accommodated. The double shaft 17 is also arranged along the direction in which the cylinders 3 are arranged, like the camshaft 13 on the exhaust side. One end portion (one side) of the double shaft 17, that is, one end portion of the outer cam shaft 17 a is connected to one end of the cylinder head 2 via a bracket 37 attached to the end of the outer cam shaft 17 a. It is rotatably supported by a bearing portion 18a installed at the end (one side). The intermediate portion of the outer camshaft 17a is rotatably supported by an intermediate bearing portion 18b installed between the tappets 9,9. Thus, both shafts 17a, 17b can be rotated about the same axis. The outer camshaft 17a and the inner camshaft 17b can be relatively displaced by a clearance.

The outer camshaft 17a is provided with a pair (two: plural) of intake cams 19 corresponding to the pair of intake valves 10 for each cylinder. Each of the intake cams 19 is configured by combining a fixed cam 20 (corresponding to the reference fixed cam of the present application) that defines a reference phase and a movable cam lobe 22 (corresponding to the assembled cam of the present application) different from the fixed cam 20. The
That is, the fixed cam 20 serving as the reference side is provided integrally with an outer peripheral portion corresponding to a tappet on one side of the outer cam shaft 17a, for example, the tappet 9 on the left side. Specifically, the fixed cam 20 is formed of a plate cam, and is fixed by being fitted to the outside of the outer cam shaft 17a, specifically, fixed by press-fitting. The cam surface 20a formed on the outer peripheral surface of the fixed cam 20 abuts on the crowned top portion 9a of the left tappet 9, and the cam displacement of the fixed cam 20 is transmitted to the left intake valve 10b.

  The cam lobe 22 has a cam nose 22a formed by a plate cam. A portion for ensuring stability, that is, a hollow boss portion 22b is combined with the cam nose portion 22a to constitute the entire cam lobe. The cam crest portion 22a and the boss portion 22b are fitted on the outer side of the outer cam shaft 17a so as to be freely rotatable (displaceable) in the circumferential direction, and the cam crest portion 22a is disposed immediately above the remaining right tappet 9. The cam surface 22c formed on the outer peripheral surface of the cam peak portion 22a abuts on the crowned top portion 9a of the right tappet 9, and the cam displacement of the cam peak portion 22a is transmitted to the right intake valve 10a.

  The boss portion 22b and the inner camshaft 17b are connected while allowing relative displacement of the inner and outer shafts 17a and 17b by a connecting member, for example, a press-fit pin 24 that is press-fitted so as to penetrate the diameter direction of the double shaft 17. ing. By this connection, the cam crest 22 a (cam lobe 22) can be displaced relative to the fixed cam 20. That is, as shown in FIG. 4, holes that allow the press-fit pins 24 to escape, for example, a pair of long holes 26 extending in the retarded direction, are formed in the peripheral wall portions of the outer cam shaft 17 a through which the press-fit pins 24 pass. The inner cam shaft 17b can be displaced relative to the outer cam shaft 17a. Thus, the cam crest portion 22a can be varied until it is largely retarded from the phase of the reference fixed cam 20. In FIG. 4, 14a indicates a press-fitting hole formed in the inner cam shaft 17b, and 14b indicates a press-fitting hole formed in the peripheral wall portion of the boss portion 22b.

For example, a cam phase changing mechanism 25 that relatively displaces the inner and outer shafts 17a and 17b is attached to one end portion of the double shaft 17 so that the cam phase of the cam lobe 22 can be changed based on the fixed cam 20. A valve device 15 is configured.
For example, as shown in FIGS. 2 and 4, the cam phase changing mechanism 25 includes a plurality of vanes radially from the outer peripheral portion of the shaft portion 32 in a cylindrical housing 31 having a plurality of retarding chambers 30 along the circumferential direction. A rotating vane structure is used in which the vane portion 34 projecting from 33 is rotatably accommodated and each vane 33 partitions the inside of each retarded angle chamber 30. A timing sprocket 39 is provided on the outer peripheral portion of the housing 31. The sprocket 39 is connected via a timing chain 40 to a crankshaft (not shown) together with a timing sprocket 13a attached to the end of the camshaft 13 on the exhaust side. The housing 31 is connected to a bracket 37 (shown in FIG. 2) at the end of the outer cam shaft 17a by a fixing bolt 36, and the shaft portion 32 of the remaining vane portion 34 is connected to the shaft end of the inner cam shaft 17b by a fixing bolt 38. When the vane 33 is connected and rotationally displaced in the retard chamber 30, the inner cam shaft 17b is displaced relative to the outer cam shaft 17a.

  More specifically, the cam phase of the cam peak portion 22a is determined by the urging force of a return spring member 42 (shown only in FIG. 2) provided so as to pass between the housing 31 and the vane portion 34. Aligned to 20 cam phases. Each retard chamber 30 is provided with an oil control valve 44 (hereinafter referred to as OCV 44) through various oil passages 43 (only part of which are shown in FIG. 2) formed in the housing 31, the bracket 37, and the bearing portion 18a. , Connected to a hydraulic pressure supply unit 45 (for example, a device having an oil pump for supplying oil). That is, when the oil is supplied into each retarding angle chamber 30, the camshaft 14 on the intake side is split so that the cam peak portion 22a is displaced from the fixed cam 20 in the retarding direction.

  That is, the split variable will be described. The shaft output from the crankshaft is transmitted to the outer shaft 17a via the timing chain 40, the timing sprocket 39, the housing 31, and the bracket 37, and the fixed cam 20 is driven to rotate. Then, the left intake valve 10b is opened and closed. Here, when the hydraulic pressure is supplied from the OCV 44 to the advance chamber (not shown) on the opposite side of each retard chamber 30, the cam crest portion 22 a is coupled with the urging force of the return spring member 42 as shown in FIG. Since the cam phase of the fixed cam 20 is aligned as in the state A, the right intake valve 10a is opened and closed while maintaining the same phase as that of the left fixed cam 20. When the hydraulic pressure of the hydraulic pressure supply unit 45 is supplied into the retard chamber 30 through the OCV 44, the vane 33 is displaced from the initial position to the retard side in the retard chamber 30 according to the hydraulic pressure output. At this time, for example, when the vane 33 is displaced halfway in the retard chamber 30 by hydraulic pressure output control, the inner cam shaft 17b is displaced in the retard direction to the midway position. The displacement at this time is transmitted to the cam lobe 22 through the press-fit pin 24, and the cam peak portion 22a is displaced in the retarding direction. Then, as shown in the state B in FIG. 5, the open / close timing of the left intake valve 10b as a reference remains unchanged, and only the open / close timing of the right intake valve 10a changes. That is, the right intake valve 10a is opened / closed according to the cam profile of the cam peak portion 22a from the middle of the opening / closing period of the left intake valve 10b. When the vane 33 is displaced to the most retarded position by hydraulic output control, the opening and closing timing of the left intake valve 10b remains unchanged as shown in the state C in FIG. 5, and the right intake valve 10a is left unchanged. Opens and closes at the most retarded time from the left intake valve 10b while maintaining a state in which the left intake valve 10b opens and closes. That is, the valve opening periods of the left and right intake valves 10 are varied within the range from the smallest valve opening period α to the largest valve opening period β (split variable) according to the state of the engine.

The variable valve operating device 15 that causes the cam lobe 22 to be phased with respect to the fixed cam 20 has a problem peculiar to the device 15 because the cam lobe 22 is rotatable.
That is, the intake side camshaft 14 (shaft member with an assembly cam) is required to be able to displace the cam lobe 22 as an assembly cam, unlike the exhaust side camshaft 13 in which the cam is integrally formed. There is a minute clearance necessary for displacement between the outer camshaft 17a. Moreover, since the clearance includes the component tolerance of the cam lobe 22 and the outer cam shaft 17a and the assembly tolerance when assembling both components, the cam crest 22a is easily displaced over a wide range, and the posture of the cam surface 22c is likely to vary ( Not constant). For this reason, as shown in FIG. 6A, the cam surface 22c is likely to be misaligned with respect to the center of the cam shaft.

  Further, the structure in which the cam phase of the cam peak portion 22a is varied with reference to the fixed cam 20 is that the valve lift load acts on the fixed cam 20 and cam peak portion 22a with a time difference in the states B and C in FIG. May cause misalignment. To explain this point, a general cam shaft (exhaust cam shaft 13) in which a cam is integrally fixed to a shaft has a cam journal between the cam at the fixed cam position and the cam at the cam lobe position. In this case, when both cams have substantially the same valve lift and timing, the valve lift load acts equally on the cam journal width, so that misalignment does not increase. However, when the phase of the fixed cam 20 and the cam lobe 22 is shifted in the variable valve operating device 15, the valve lift load acts on the cam journal 18b in the width direction before and after the cam journal 18b, and a large misalignment occurs.

  When such misalignment of the cam surface 22c occurs, as shown in FIG. 6A, contact between the crowned top portion 9a, which is a predetermined position of the cam contact surface of the tappet 9, and the cam width end portion occurs. There is. In addition, the valve lift may not be performed according to the designed cam. When this occurs, as shown in FIG. 6A, the cam surface 22c has a reduced contact area with the cam contact portion of the tappet 9, resulting in a high load, and a good lubrication state cannot be maintained. This causes an increase in friction at the contact portion and uneven wear.

  Therefore, the above-mentioned point was improved by adopting an idea that the cam width of the assembly cam and the cam width of the cam with the common shaft are not the same but different. Specifically, as shown in FIG. 1, the cam width dimension a of the cam surface 22c of the cam crest 22a that varies the phase is set to the cam width dimension of the camshaft formed integrally with the cam, here the exhaust side. The cam width 13 of the cam surface 12a of the exhaust cam 12 (fixed cam) of the camshaft 13 is larger (a> c).

  As a result, as shown in FIG. 6B, even if misalignment occurs, contact between the crowned top surface 9a of the cam contact surface of the tappet 9 and the cam width end portion of the cam peak portion 22a is avoided. It is done. That is, the contact area with the top surface 9a (cam contact portion) due to misalignment of the cam surface 22c is maintained. Thereby, the load of the contact part in the cam peak part 22a and the top surface 9a can be disperse | distributed, and a maximum load also falls.

  The cam width dimension b of the cam surface 20a of the reference side fixed cam 20 is also made larger than the cam width dimension c of the cam surface 12a of the exhaust cam 12 of the exhaust side camshaft 13 (fixed cam integrated with the shaft). is there. Thereby, also about the fixed cam 20, the contact of the cam width end part of the cam surface 20a and the top surface 9a is avoided, and the contact area with the top surface 9a (cam contact portion) due to misalignment of the cam surface 20a. Is maintained.

When the cam width of the cam peak portion 22a is increased, the allowable range for misalignment on the cam surface 22c of the cam peak portion 22a increases. In addition, since the stability of the cam peak portion 22a itself is increased, the influence of the clearance and assembly tolerance for rotating the cam peak portion 22a is suppressed. This is also true for the increased cam width of the fixed cam 20 on the reference side.
Therefore, the tolerance to the misalignment of the cam that changes the phase can be enhanced with a simple structure. This is due to the misalignment associated with the variable split in which the cam crest 22a is displaced in the circumferential direction with respect to the fixed cam 20, that is, the misalignment that occurs when a valve lift load acts on the cam journal width direction before and after the time difference. Is the same.

  Therefore, the camshaft 14 can be assembled to the cylinder head 2 in the same manner as the conventional cam (FIG. 2), and it is possible to suppress troublesome alignment work and improvement of the processing accuracy of each of the previous components (no processing accuracy is required). ). Furthermore, the maximum value of the unbalanced load acting on the sliding surfaces of the cam nose 22a (assembled cam) and the outer camshaft 17a due to misalignment is also reduced, and the deterioration of responsiveness and uneven wear due to increased friction can be suppressed. In addition, the inclination of the cam nose 22a can be suppressed by increasing the cam width dimension, so the occurrence of friction and uneven wear due to the instability of the cam nose 22a can be suppressed, and good variable performance can be secured. can do. In addition, since the valve lift as designed is obtained, there is no performance degradation or NVH deterioration. In addition, since the outer cam shaft 17a is formed of a pipe member having low bending rigidity, if the cam width of the cam peak portion 22a is increased, the force transmitted from the cam peak portion 22a to the outer cam shaft 17a is dispersed, which is good. Variable performance is maintained.

In particular, as shown in FIGS. 2 and 4, the cam width dimension a of the cam crest 22a is larger than the cam width dimension b of the reference fixed cam 20 (a> b, a> c, b>). c). In this way, by setting the optimum cam width to each other, it is possible to effectively cope with the effects of component tolerances, assembly tolerances, and misalignment associated with variable splitting.
Needless to say, such an effect can also be obtained when the crowning of the cam contact surface of the tappet 9 is provided on the cam surface 22c side.

FIG. 7 shows a second embodiment of the present invention.
In the present embodiment, a phase change device is provided at one end of a double shaft 17 (shaft member) in which a fixed cam 20 (first cam) and a cam lobe 22 (second cam) are assembled as in the first embodiment. 25, and not the variable valve operating device 15 that varies the phase of the cam lobe 22 with respect to the fixed cam 20, but a variable valve operating device 50 to which a function of integrally changing the phase of the fixed cam 20 and the phase of the cam lobe 22 is added. Further, the present invention is applied.

  That is, the variable valve operating apparatus 50 has a first implementation at one end of the double shaft 17 assembled with the fixed cam 20 (reference fixed cam) and the cam lobe 22 (assembled cam), for example, at the end on the rear side of the engine. A phase change mechanism 25 (first) having the same structure as that of the embodiment is connected, and a second phase change mechanism 51 formed of a rotary vane structure such as VVT is connected to the other engine front side end, In addition to the variable phase due to the relative displacement of the outer cam shaft 17a and the inner cam shaft 17b, the phase of the fixed cam 20 and the cam lobe 22 is integrally variable due to the integral rotational displacement of the outer cam shaft 17a and the inner cam shaft 17b. It is made to be done.

Even when the present invention is applied to the variable valve apparatus 50, the same effects as those of the first embodiment can be obtained. However, in FIG. 7, the same parts as those of the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.
In addition, this invention is not limited to any embodiment mentioned above, You may implement variously within the range which does not deviate from the main point of this invention. For example, in the embodiment, the structure in which the valve is driven by receiving the cam displacement with the tappet is described. However, the present invention is not limited to this, and the present invention is applied to a structure in which the valve is driven by receiving the cam displacement with another driven member, for example, the rocker member. You may apply. When a valve is driven by a rocker member, there is a case where a single cam contact surface is provided on the cam side of the rocker member, a bifurcated valve drive unit is provided on the valve side, and a plurality of valves are driven by one cam. In this case, the cam width dimension refers to a dimension per valve obtained by dividing the actual cam width by the number of drive valves (= actual cam shaft / number of drive valves). Of course, the present invention is not limited to the variable valve operating apparatus that relatively changes the phase of the pair of intake cams as in the above-described embodiment. You may apply to a valve apparatus.

10 Intake valve 12 Exhaust cam (fixed cam)
12a Cam surface of exhaust cam 13 Exhaust camshaft (camshaft member)
14 Inlet camshaft (shaft member with built-in cam)
15 Variable valve gear 19 Intake cam 20 Fixed cam (reference fixed cam)
20a Cam surface of fixed cam 22a Cam crest (assembled cam)
22c Cam surface of cam crest 25 Cam phase change mechanism a Cam width of cam crest b Cam width of fixed cam c Cam width of exhaust cam (fixed cam)

Claims (3)

A variable valve operating apparatus comprising a plurality of shaft members driven by a crank output of an internal combustion engine,
The plurality of shaft members are:
A shaft member with an assembly cam to which an assembly cam having a cam surface for driving the intake valve or the exhaust valve is assembled;
In addition to the shaft member with the assembly cam, a cam shaft member integrally formed with a fixed cam, and
The variable valve operating apparatus for an internal combustion engine, wherein the cam surface of the assembly cam is formed with a cam width dimension larger than the cam width of the cam surface of the fixed cam. A plurality of intake valves or exhaust valves are provided for one cylinder;
The shaft member with the assembly cam is integrally formed with a reference fixing cam that drives any of the plurality of intake valves or exhaust valves separately from the assembly cam,
The cam surface of the reference fixed cam is formed with a cam width dimension larger than the cam width of the cam surface of the fixed cam formed integrally with the camshaft member. The variable valve operating apparatus for an internal combustion engine. The assembly cam is assembled so as to be displaceable in the circumferential direction on the outside of the shaft member with the assembly cam.
A cam phase change mechanism for changing the phase of the assembly cam with respect to the reference fixed cam;
The variable motion of the internal combustion engine according to claim 1 or 2, wherein the cam surface of the assembly cam is formed with a cam width dimension larger than the cam width of the cam surface of the reference fixed cam. Valve device.

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