US20120145101A1 - Variable valve device for an internal combustion engine - Google Patents

Variable valve device for an internal combustion engine Download PDF

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Publication number
US20120145101A1
US20120145101A1 US13/392,460 US201013392460A US2012145101A1 US 20120145101 A1 US20120145101 A1 US 20120145101A1 US 201013392460 A US201013392460 A US 201013392460A US 2012145101 A1 US2012145101 A1 US 2012145101A1
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Prior art keywords
cam
camshaft
valve device
internal combustion
combustion engine
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Abandoned
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US13/392,460
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English (en)
Inventor
Daisuke Yoshika
Shinichi Murata
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Mitsubishi Motors Corp
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Mitsubishi Motors Corp
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
    • F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
    • F01L1/34—Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of means for changing the timing of the valves without changing the duration of opening and without affecting the magnitude of the valve lift
    • F01L1/344—Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of means for changing the timing of the valves without changing the duration of opening and without affecting the magnitude of the valve lift changing the angular relationship between crankshaft and camshaft, e.g. using helicoidal gear
    • F01L1/3442—Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of means for changing the timing of the valves without changing the duration of opening and without affecting the magnitude of the valve lift changing the angular relationship between crankshaft and camshaft, e.g. using helicoidal gear using hydraulic chambers with variable volume to transmit the rotating force
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
    • F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
    • F01L1/34—Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of means for changing the timing of the valves without changing the duration of opening and without affecting the magnitude of the valve lift
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
    • F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
    • F01L1/02—Valve drive
    • F01L1/04—Valve drive by means of cams, camshafts, cam discs, eccentrics or the like
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
    • F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
    • F01L1/02—Valve drive
    • F01L1/04—Valve drive by means of cams, camshafts, cam discs, eccentrics or the like
    • F01L1/047—Camshafts
    • F01L1/053—Camshafts overhead type
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
    • F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
    • F01L1/12—Transmitting gear between valve drive and valve
    • F01L1/14—Tappets; Push rods
    • F01L1/143—Tappets; Push rods for use with overhead camshafts
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
    • F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
    • F01L1/34—Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of means for changing the timing of the valves without changing the duration of opening and without affecting the magnitude of the valve lift
    • F01L1/344—Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of means for changing the timing of the valves without changing the duration of opening and without affecting the magnitude of the valve lift changing the angular relationship between crankshaft and camshaft, e.g. using helicoidal gear
    • F01L1/34413—Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of means for changing the timing of the valves without changing the duration of opening and without affecting the magnitude of the valve lift changing the angular relationship between crankshaft and camshaft, e.g. using helicoidal gear using composite camshafts, e.g. with cams being able to move relative to the camshaft
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
    • F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
    • F01L1/02—Valve drive
    • F01L1/04—Valve drive by means of cams, camshafts, cam discs, eccentrics or the like
    • F01L1/047—Camshafts
    • F01L2001/0471—Assembled camshafts
    • F01L2001/0473—Composite camshafts, e.g. with cams or cam sleeve being able to move relative to the inner camshaft or a cam adjusting rod
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
    • F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
    • F01L1/02—Valve drive
    • F01L1/04—Valve drive by means of cams, camshafts, cam discs, eccentrics or the like
    • F01L1/047—Camshafts
    • F01L1/053—Camshafts overhead type
    • F01L2001/0537—Double overhead camshafts [DOHC]
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
    • F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
    • F01L1/34—Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of means for changing the timing of the valves without changing the duration of opening and without affecting the magnitude of the valve lift
    • F01L1/344—Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of means for changing the timing of the valves without changing the duration of opening and without affecting the magnitude of the valve lift changing the angular relationship between crankshaft and camshaft, e.g. using helicoidal gear
    • F01L1/3442—Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of means for changing the timing of the valves without changing the duration of opening and without affecting the magnitude of the valve lift changing the angular relationship between crankshaft and camshaft, e.g. using helicoidal gear using hydraulic chambers with variable volume to transmit the rotating force
    • F01L2001/3445—Details relating to the hydraulic means for changing the angular relationship
    • F01L2001/34483—Phaser return springs

Definitions

  • the invention relates to a variable valve device for an internal combustion engine, which changes the phase of either one of a pair of cams that activates a pair of intake or exhaust valves in relation to the other cam by means of a cam-phase changing mechanism.
  • a variable valve device is mounted on a cylinder head to take measure against engine exhaust emission and reduce pumping loss.
  • the variable valve device has a structure that varies valve phases in a multivalve (a pair of intake valves and a pair of exhaust valves) that is often employed in engines, to thereby change a period in which the multivalve is open.
  • a system has been proposed, which varies the phase of either one of a pair of cams that activates a pair of intake or exhaust valves in relation to the other cam.
  • variable valve device is difficult to be materialized with a common camshaft in which a cam forms an integral part of a shaft member. For that reason, the variable valve device utilizes a camshaft having an assembled cam structure, in which a separate cam member (part) is rotatably fastened to a shaft member, to vary valve phases.
  • a first cam on a fixed side is fixed to the outside of the shaft member that is driven by crank output according to the layout of a pair of intake or exhaust valves
  • a second cam that is a counterpart of the first which has a cam width identical to the first cam and is located on a movable side, is fitted to be displaceable in a circumferential direction.
  • the phase of the second cam is changed on the basis of the phase of the first cam by using a cam-phase changing mechanism such as a movable vane mechanism.
  • the displacement of the first and second cams is transmitted to each valve via a driven member of a tappet member (or a rocker member or the like), changing to a great degree a period in which the pair of intake or exhaust valves is open.
  • the cam faces of the first and second cams are reduced in contact area with respect to a cam-contact portion of a tappet and that of a rocker, and are applied with high load.
  • the cam faces then become incapable of maintaining adequate lubrication, which triggers an increase in friction or local wear in contact portions.
  • the second cam used in the variable valve device is pivotable in a circumferential direction of the shaft member.
  • the clearance encourages the misalignment of the second cam and leads to an increase in further friction against the cam-contact portions of the tappet and the rocker, and local wear.
  • the misalignment destabilizes the clearance and increases a bias load applied onto a sliding surface of the second cam and that of the shaft member. Due to the increase of friction, response is deteriorated, and wear appears in the site of friction.
  • variable valve device has the problem that its variable performance is fluctuated when these events take place.
  • a considerable way to solve this problem is to carry out the processing for correcting the misalignment, to improve assembly precision, to utilize materials with high abrasion resistance that can cope with misalignment or to apply surface treatment.
  • they are all costly alternatives, and there has been a demand for some other technology.
  • a variable valve device for an internal combustion engine claimed in claim 1 which varies valve phases of a pair of intake valves or valve phases of a pair of exhaust valves, which is provided to each cylinder, the device having a shaft member that is driven by crank output of an internal combustion engine; a first cam that is disposed in the outside of the shaft member and has a cam face that drives one of the pair of intake valves or one of the pair of exhaust valves; a second cam that is disposed in the outside of the shaft member to be displaceable in a circumferential direction and has a cam face that drives the other intake valve or the other exhaust valve; and a cam-phase changing mechanism that changes a phase of the second cam relative to the first cam, wherein the cam face of the second cam is formed to have a cam width dimension that is larger than cam width of the cam face of the first cam.
  • variable valve device for an internal combustion engine claimed in claim 2 is configured by pivotably fitting an inner camshaft into an outer camshaft made up of a pipe member; the first cam is disposed in an outer periphery of the outer camshaft, and the second cam is disposed to be pivotable around an axis of the outer camshaft; and a phase of the second cam is variable on the basis of the first cam in response to a relative displacement of the outer camshaft and the inner camshaft.
  • variable valve device for an internal combustion engine claimed in claim 3 according to claim 1 or 2 the first cam is formed to have a cam width dimension that is larger than cam width of a camshaft having a cam that forms an integral part of a shaft member applied in an internal combustion engine of the same model.
  • variable valve device for an internal combustion engine claimed in claim 1 contact area between the cam faces of the first and second cams and the cam-contact portions of the tappet and the rocker is maintained even in a misaligned state. This makes it possible to retain adequate lubrication, prevent an increase in friction and local wear in the contact portions, and reduce a maximum value of the bias load created by misalignment, which is applied onto the sliding surface of the second cam and that of the shaft member.
  • the outer camshaft is made up of the pipe member having a low flexural rigidity. It is then possible to disperse the force applied from the second cam to the outer camshaft by using the second cam having a large cam width dimension.
  • the first and second cams have respective optimum cam widths, and can effectively respond to misalignment caused by split change. It is therefore possible to effectively prevent a deterioration in response and local wear resulting from friction increase.
  • FIG. 1 is a plan view showing an internal combustion engine equipped with a variable valve device according to a first embodiment of the invention
  • FIG. 2 is a sectional view of the variable valve device, taken along line I-I of FIG. 1 ;
  • FIG. 3 is a sectional view of a camshaft in which a cam forms an integral part
  • FIG. 4 is an exploded perspective view showing a configuration of each part of the variable valve device
  • FIG. 5 is a line graph showing a variable property of the variable valve device
  • FIG. 6 includes views for explaining a difference in a contact state between the cam and a tappet, which is caused by a change in cam width;
  • FIG. 7 is a plan view showing a main part of a second embodiment of the invention.
  • FIGS. 1 to 6 The present invention will be described below with reference to a first embodiment shown in FIGS. 1 to 6 .
  • FIG. 1 is a plan view of a reciprocal engine (hereinafter, referred to as engine), for example, of a multi-cylinder type.
  • FIG. 2 shows a cross-section taken along line I-I of FIG. 1 .
  • 1 represents a cylinder block of the engine
  • 2 represents a cylinder head installed in a head of the cylinder block 1 .
  • a plurality of cylinders 3 are formed along an anteroposterior direction of the engine as shown in FIGS. 1 and 2 .
  • the cylinders 3 contain respective pistons 4 , which are split from a crankshaft (not shown) via a con rod (not shown), so that the pistons 4 are capable of making reciprocating motion.
  • a combustion chamber 5 is formed under a lower face of the cylinder head 2 correspondingly to each of the cylinders 3 .
  • a pair of intake ports 7 (two) that intakes air and a pair of exhaust ports (not shown) that exhausts air are open.
  • Each of the intake ports 7 is provided with a pair of intake valves 10 (two) whose stem ends are each attached with a bottomed cylinder-shaped tappet 9 (driven member).
  • a spherical crowning (cam-contact face) formed in a top face 9 a of the tappet 9 faces an upper portion of the cylinder head 2 .
  • each of the exhaust ports is provided with a pair of exhaust valves (not shown) having tappets, and a valve base end faces the upper portion of the cylinder head 2 .
  • the intake ports 7 and the exhaust ports (not shown) are opened/closed by the intake valves 10 and the exhaust valves (not shown), respectively.
  • an ignition plug is also provided to each of the combustion chambers 5 .
  • An intake-side valve system 6 a that is driven by shaft output of the crankshaft and an exhaust-side valve system 6 b are disposed side by side on the upper portion of the cylinder head 2 .
  • a predetermined combustion cycle (including four processes, namely, intake process, compression process, expansion process and exhaust process) is repeated in the cylinders 3 .
  • the exhaust-side valve system 6 b of the valve systems 6 a and 6 b has a configuration using, for example, a common camshaft 13 shown in FIG. 3 .
  • the camshaft 13 is a camshaft in which an exhaust cam forms an integral part, and more specifically, in which an exhaust cam 12 for a plurality of cylinders is formed integrally with a shaft 13 a (shaft member) by machining.
  • the camshaft 13 is rotatably installed to extend in a direction that the cylinders 3 are aligned and brings the cam faces of the exhaust cams 12 into contact with the crownings (not shown) of the tappets' top faces. In this way, the cam displacement of the exhaust cams 12 is transmitted to the exhaust valves (not shown).
  • the intake-side valve system 6 a also uses a camshaft that is configured by assembling separate parts as shown in FIG. 4 unlike the exhaust-side camshaft 13 , or a camshaft 14 having a so-called assembled cam structure.
  • the camshaft 14 is used to configure a split-type variable valve device 15 as shown in FIG. 12 .
  • the shaft member of the camshaft 14 is formed of a double shaft 17 (corresponding to the shaft member of the present invention) in which an inner camshaft 17 b made of a solid shaft member serving as a control member is swingably contained in an outer camshaft 17 a made of a pipe member, for example, as shown in FIGS. 2 and 4 .
  • the double shaft 17 is disposed along the direction in which the cylinders 3 are aligned in the same manner as with the exhaust-side camshaft 13 .
  • One of end portions (one side) of the double shaft 17 that is, one of end portions of the outer camshaft 17 a is pivotably supported by a bearing 18 a that is set in one of end portions (one side) of the cylinder head 2 through a bracket 37 that is attached to an end of the outer camshaft 17 a.
  • a middle portion of the outer camshaft 17 a is rotatably supported by a middle bearing 18 b that is set between the tappets 9 . This way, the shafts 17 a and 17 b are concentrically rotatable.
  • the outer camshaft 17 a and the inner camshaft 17 b are displaceable relative to each other due to clearance.
  • the outer camshaft 17 a is provided with a pair (two) of intake cams 19 corresponding to the pair of intake valves 10 of each cylinder.
  • Each of the intake cams 19 is configured by assembling a fixed cam 20 (corresponding to the first cam of the present invention) that determines a base phase and a cam lobe 22 (which is a movable cam and corresponds to the second cam of the present invention) located on a movable side.
  • the fixed cam 20 on a base side is disposed in an outer periphery corresponding to one of the tappets of the outer camshaft 17 a, for example, the tappet 9 on the left side in the drawing.
  • the fixed cam 20 is formed of a plate cam, and is fixed by being fitted, and more specifically, press-fitted to the outer side of the outer camshaft 17 a.
  • a cam face 20 a formed in an outer circumferential surface of the fixed cam 20 comes into contact with the top face 9 a provided with the crowning of the left-side tappet 9 . The cam displacement of the fixed cam 20 is thus transmitted to the left-side intake valve 10 b.
  • the cam lobe 22 has a cam nose 22 a formed of a plate cam.
  • the cam nose 22 a is interlocked with a portion for securing stability, that is, a hollow boss 22 b.
  • the entire cam lobe is thus configured.
  • the cam nose 22 a and the boss 22 b are fitted to the outer side of the outer camshaft 17 a to be pivotable (displaceable) in a circumferential direction.
  • the cam nose 22 a is disposed immediately above the right-side tappet 9 .
  • a cam face 22 c formed in an outer circumferential surface of the cam nose 22 a comes into contact with the top face 9 a provided with the crowning of the right-side tappet 9 .
  • the cam displacement of the cam nose 22 a is thus transmitted to the right-side intake valve 10 a.
  • the boss 22 b and the inner camshaft 17 b are interlocked with each other by using a connecting member, that is, for example, a press-fit pin 24 press-fitted to run through the double shaft 17 in a diametrical direction while allowing the relative displacement of the inner and outer shafts 17 a and 17 b.
  • a connecting member that is, for example, a press-fit pin 24 press-fitted to run through the double shaft 17 in a diametrical direction while allowing the relative displacement of the inner and outer shafts 17 a and 17 b.
  • This interlock enables the cam nose 22 a (cam lobe 22 ) to displace relative to the fixed cam 20 .
  • a hole that allows the press-fit pin 24 to escape for example, a pair of long holes 26 extending in a retard direction is formed in a circumferential wall of the outer camshaft 17 a, through which the press-fit pin 24 penetrates as shown in FIG. 4 .
  • the inner camshaft 17 b is thus displaceable relative to the outer camshaft 17 a. This enables the cam nose 22 a to be variable from the phase of the fixed cam 20 serving as a base to a retard phase to a great degree.
  • Reference numerals 14 a and 14 b in FIG. 4 represent a press-fit hole formed in the inner camshaft 17 b and a press-fit hole formed in a circumferential wall of the boss 22 b, respectively.
  • a cam-phase changing mechanism 25 that displaces the inner and outer shafts 17 a and 17 b relative to each other is mounted on one of the end portions of the double shaft 17 .
  • the variable valve device 15 is thus configured, in which the cam phase of the cam lobe 22 is changeable on the basis of the fixed cam 20 .
  • the cam-phase changing mechanism 25 has a pivot vane structure in which a vane portion 34 whose shaft portion 32 has a plurality of vanes 33 radially projecting from an outer periphery thereof is pivotably contained in a cylindrical housing 31 including a plurality of retard chambers 30 arranged in a circumferential direction, and the vanes 33 partition the inside of the retard chambers 30 .
  • a timing sprocket 39 is disposed in an outer periphery of the housing 31 .
  • the sprocket 39 is interlocked with a crankshaft (not shown) through a timing chain 40 together with a timing sprocket 13 a mounted on the end of the exhaust-side camshaft 13 .
  • the housing 31 is interlocked with a bracket 37 (shown in FIG. 2 ) located at the end of the outer camshaft 17 a by using a fixing bolt 36 .
  • the shaft portion 32 of the vane portion 34 is interlocked with a shaft end of the inner camshaft 17 b by using a fixing bolt 38 .
  • the cam phase of the cam nose 22 a is aligned with the cam phase of the fixed cam 20 serving as a base by a biasing force of a return spring member 42 (shown only in FIG. 2 ) that is set to bridge between the housing 31 and the vane portion 34 .
  • Each of the retard chambers 30 is connected to an oil control valve 44 (hereinafter, referred to as OCV 44 ) and a hydraulic supplier 45 (that is formed, for example, of a device having an oil pump for supplying oil) through various oil passages 43 (partially shown in FIG. 2 ) formed in the housing 31 , the bracket 37 and the bearing 18 a.
  • OCV 44 oil control valve 44
  • a hydraulic supplier 45 that is formed, for example, of a device having an oil pump for supplying oil
  • the right-side intake valve 10 a is opened/closed while maintaining the same phase as the left-side fixed cam 20 .
  • the vanes 33 are displaced from an initial position towards the retard side within the retard chambers 30 along with the output of the hydraulic pressure.
  • the inner camshaft 17 b is displaced halfway in the retard direction. The displacement is transmitted through the press-fit pin 24 to the cam lobe 22 and displaces the cam nose 22 a in the retard direction.
  • the opening/closing timing of the left-side intake valve 10 b serving as a base is unchanged as seen in a state shown by line B of FIG. 5 , and only the opening/closing timing of the right-side intake valve 10 a is changed.
  • the right-side intake valve 10 a is opened/closed according to a cam profile of the cam nose 22 a in the middle of the opening/closing period of the left-side intake valve 10 b.
  • the vanes 33 are displaced to a most retarded position, the left-side intake valve 10 b stays unchanged in opening/closing timing as seen in a state shown by line C of FIG.
  • the opening periods of the right- and left-side intake valves 10 are varied within a range from a shortest opening period a to a longest opening period ⁇ according to the condition of the engine (split change).
  • variable valve device 15 that displaces the phase of the cam lobe 22 relative to the fixed cam 20 has a unique problem because of the pivotability of the cam lobe 22 .
  • the cam lobe 22 combined with the double shaft 17 is required to be capable of making a pivoting motion in the outer circumferential surface of the outer camshaft 17 a.
  • the clearance is added with component tolerance of the cam lobe 22 and the outer camshaft 17 a and erection tolerance at the time of combining the cam lobe 22 and the outer camshaft 17 a.
  • the cam nose 22 a is therefore easy to displace in a wide range, and the cam face 22 c is prone to be fluctuated (unstable). As shown in FIG. 6( a ), the cam face 22 c is likely to be misaligned relative to the cam axis center.
  • misalignment occurs because a valve lift load is applied with time lag.
  • a cam journal between a first cam located in a fixed cam position and a second cam located in a cam lobe position, the first and second cams are almost the same in valve lift and timing, the valve lift load is applied uniformly over the width of the cam journal. This prevents an increase in misalignment.
  • variable valve device 15 when the fixed cam 20 as the first cam and the cam lobe 22 as the second cam are displaced in phase, a large misalignment takes place because the valve lift load is applied with time lags to the front and rear of the cam journal 18 b in the width direction of the cam journal 18 b.
  • cam width dimension a of the cam face 22 c of the cam nose 22 a that varies phases is increased larger than cam width dimension b of the cam face 20 a of the fixed cam 20 as shown in FIGS. 1 , 2 and 4 .
  • the cam width dimensions are differentiated from each other in this manner.
  • the cam face 22 c of the cam nose 22 a is formed to have a larger cam width than the cam face 20 a of the fixed cam 20 (a>b).
  • cam width of the cam nose 22 a is increased, an allowable range with respect to the misalignment in the cam face 22 c of the cam nose 22 a is increased. Furthermore, the cam nose 22 a itself is increased in stability, which prevents an effect of the clearance and erection tolerance for the pivoting motion of the cam nose 22 a.
  • the camshaft 14 can be combined with the cylinder head 2 as with the conventional cam ( FIG. 2 ), and thus eliminates the necessity of performing a time-consuming alignment work and improving precision in component machining at the prior stage (machining precision is not required). Furthermore, the maximum value of the bias load applied onto the sliding face of the cam nose 22 a (second cam) and that of the outer camshaft 17 a (shaft member), which is caused by misalignment, is reduced. It is therefore possible to prevent a deterioration in response and local wear resulting from friction increase.
  • the cam width dimension b of the fixed cam 20 is larger than the cam width dimension of a camshaft having a cam that forms an integral part of a shaft member, which is used in an engine of the same model, that is, for example, the cam width dimension c of the cam face of the exhaust cam 12 of the camshaft 13 having the exhaust cam 12 that forms an integral part of the shaft 13 a shown in FIG. 3 or the cam width dimension, not shown, of a cam face of an intake cam of an intake camshaft that forms an integral part of an intake cam used in a series of engines of the same model, which do not perform split change (a>c and b>c). If these cam width dimensions are set at the respective optimum values, even the fixed cam 20 configured by being combined with separate parts is not affected by erection tolerance, and it is possible to respond to the misalignment caused by split change.
  • FIG. 7 shows a second embodiment of the invention.
  • the second embodiment is formed by applying the present invention to a variable valve device 50 that is added with a function of integrally varying the phase of the fixed cam 20 and that of the cam lobe 22 , unlike the variable valve device 15 in which a phase-changing device 25 is attached to one of end portions of the double shaft 17 (shaft member), which includes the fixed cam 20 (first cam) and the cam lobe 22 (second cam) combined together as seen in the first embodiment.
  • the phase-changing mechanism 25 having the same structure as the first embodiment is connected to one of end portions of the double shaft 17 (shaft member) formed by combining the fixed cam 20 (first cam) and the cam lobe 22 (second cam), that is, for example, the end on the rear side of the engine, and a second phase-changing mechanism 51 having a pivot vane structure such as VVT (Variable Valve Timing) is connected to the end on the front side of the engine, whereby the phase of the fixed cam 20 and that of the cam lobe 22 are integrally varied on the basis of the integral pivot displacement of the outer camshaft 17 and the inner camshaft 17 b, apart from the phase change by relative displacement of the outer camshaft 17 a and the inner camshaft 17 b.
  • VVT Variable Valve Timing
  • variable valve device 50 If the present invention is applied to the variable valve device 50 , the same advantage as in the first embodiment is provided. Referring to FIG. 7 , constituents identical to those of the first embodiment are provided with the same reference marks, and descriptions thereof are omitted.
  • variable valve device for an internal combustion engine according to the invention, but the invention is not limited to the above-described embodiments.
  • the embodiments employ the structure in which cam displacement is transmitted to the tappets to drive the valves.
  • the invention may be applied to a structure in which cam displacement is transmitted to another driven member, that is, for example, a rocker member, thereby driving the valves.
  • another driven member that is, for example, a rocker member
  • the invention may be applied to a variable valve device, not shown, which changes the phases of a pair of exhaust cams relative to each other, instead of being applied to the variable valve device that changes the phases of a pair of intake cams relative to each other as in the embodiments.
  • the engine to be applied may be one having a valve system in which the variable valve device is combined with the structure that drives valves by means of a camshaft whose cam is integrally formed.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Valve Device For Special Equipments (AREA)
  • Valve-Gear Or Valve Arrangements (AREA)
US13/392,460 2009-11-25 2010-11-22 Variable valve device for an internal combustion engine Abandoned US20120145101A1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
JP2009-267506 2009-11-25
JP2009267506A JP4883330B2 (ja) 2009-11-25 2009-11-25 内燃機関の可変動弁装置
PCT/JP2010/070799 WO2011065326A1 (ja) 2009-11-25 2010-11-22 内燃機関の可変動弁装置

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US20120145101A1 true US20120145101A1 (en) 2012-06-14

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US13/392,460 Abandoned US20120145101A1 (en) 2009-11-25 2010-11-22 Variable valve device for an internal combustion engine

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US (1) US20120145101A1 (ja)
EP (1) EP2505795B1 (ja)
JP (1) JP4883330B2 (ja)
KR (1) KR101169900B1 (ja)
CN (1) CN103038458A (ja)
BR (1) BR112012004601A2 (ja)
IN (1) IN2012DN01666A (ja)
RU (1) RU2493376C1 (ja)
WO (1) WO2011065326A1 (ja)

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US20100242472A1 (en) * 2007-09-05 2010-09-30 Elsaesser Alfred Piston engine
EP2634385A1 (de) * 2012-02-29 2013-09-04 MAHLE International GmbH Verstellbare Nockenwelle
US8939117B2 (en) 2009-12-07 2015-01-27 Mitsubishi Jidosha Kogyo Kabushiki Kaisha Variable valve actuation device for internal combustion engine

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JP5288134B2 (ja) * 2009-11-25 2013-09-11 三菱自動車工業株式会社 内燃機関の可変動弁装置
JP5660405B2 (ja) * 2012-09-28 2015-01-28 株式会社デンソー バルブタイミング調整装置
DE102012220652A1 (de) 2012-11-13 2014-05-15 Mahle International Gmbh Nockenwelle
US9528399B2 (en) * 2014-10-21 2016-12-27 Ford Global Technologies, Llc Method and system for variable cam timing device
US9777604B2 (en) * 2014-10-21 2017-10-03 Ford Global Technologies, Llc Method and system for variable cam timing device
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US9587525B2 (en) * 2014-10-21 2017-03-07 Ford Global Technologies, Llc Method and system for variable cam timing device
US9410453B2 (en) * 2014-10-21 2016-08-09 Ford Global Technologies, Llc Method and system for variable cam timing device
JP6070730B2 (ja) * 2015-01-15 2017-02-01 トヨタ自動車株式会社 内燃機関の可変動弁装置

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US8857177B2 (en) * 2007-09-05 2014-10-14 Mahle International Gmbh Piston engine
US8939117B2 (en) 2009-12-07 2015-01-27 Mitsubishi Jidosha Kogyo Kabushiki Kaisha Variable valve actuation device for internal combustion engine
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Publication number Publication date
EP2505795A1 (en) 2012-10-03
EP2505795B1 (en) 2014-06-11
KR101169900B1 (ko) 2012-07-31
JP2011111936A (ja) 2011-06-09
JP4883330B2 (ja) 2012-02-22
KR20120039741A (ko) 2012-04-25
IN2012DN01666A (ja) 2015-06-05
BR112012004601A2 (pt) 2016-04-05
EP2505795A4 (en) 2013-04-24
RU2493376C1 (ru) 2013-09-20
WO2011065326A1 (ja) 2011-06-03
CN103038458A (zh) 2013-04-10

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