US20090120392A1 - Valve timing adjusting apparatus - Google Patents
Valve timing adjusting apparatus Download PDFInfo
- Publication number
- US20090120392A1 US20090120392A1 US12/264,347 US26434708A US2009120392A1 US 20090120392 A1 US20090120392 A1 US 20090120392A1 US 26434708 A US26434708 A US 26434708A US 2009120392 A1 US2009120392 A1 US 2009120392A1
- Authority
- US
- United States
- Prior art keywords
- vane
- housing
- hole
- adjusting apparatus
- oil pressure
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
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Classifications
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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
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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
- F01L1/02—Valve drive
- F01L1/022—Chain drive
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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
- F01L2001/3445—Details relating to the hydraulic means for changing the angular relationship
- F01L2001/34453—Locking means between driving and driven members
- F01L2001/34469—Lock movement parallel to camshaft axis
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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
- F01L2001/3445—Details relating to the hydraulic means for changing the angular relationship
- F01L2001/34479—Sealing of phaser devices
Definitions
- the present invention relates to a valve timing adjusting apparatus for changing opening and closing timing of at least one of an intake valve and an exhaust valve for an internal combustion engine or an engine in accordance with an operational condition.
- valve timing adjusting apparatus which drives a camshaft via a timing pulley of a housing rotatable in time with a crank shaft of the engine, and via a chain sprocket.
- the above valve timing adjusting apparatus controls a phase relationship between the crank shaft and the camshaft using pressure of hydraulic oil that flows into an advance oil pressure chamber and a retard oil pressure chamber, which serve as pressure chambers (see, for example, JP-A-2003-201810 corresponding to US 2003/0121485).
- the operation of the engine may stop in a state, where the stopper piston is not fitted with the fitting hole of the housing.
- variable torque of the camshaft it is required that variable torque of the camshaft be used to fluctuate the vane rotor such that the stopper piston is brought into a fitted relation with the fitting hole of the housing, and thereby the relative rotation of the vane rotor relative to the housing is limited.
- the fitting hole of the housing is usually filled with hydraulic oil.
- the stopper piston pushes back hydraulic oil in the fitting hole toward an oil passage.
- the stopper piston has a tip end portion having a diameter larger than a diameter of the oil passage, pressure loss caused by the pushing of hydraulic oil by the stopper piston during the fitting of the stopper piston is large, and thereby response of the stopper piston speed is reduced.
- the responsivity of stopper piston may remarkably deteriorate specifically when temperature is low, such as at the start of the engine, in which a degree of viscosity of hydraulic oil is large.
- the present invention is made in view of the above disadvantages. Thus, it is an objective of the present invention to address at least one of the above disadvantages.
- a valve timing adjusting apparatus that is provided to a driving force transmission system for transmitting a driving force from a first shaft of an internal combustion engine to a second shaft that actuates at least one of an intake valve and an exhaust valve, wherein the valve timing adjusting apparatus adjusts opening and closing timing of the at least one of the intake valve and the exhaust valve.
- the valve timing adjusting apparatus includes a housing, a vane supporting portion, a vane member, a limiting member, a fitting hole, and an atmosphere communication hole.
- the housing is rotatable about a rotation axis with one of the first shaft and the second shaft.
- the housing includes a peripheral wall and side walls that are connected to both axial ends of the peripheral wall along the rotation axis.
- the housing defines a receiving chamber by the peripheral wall and the side walls.
- the vane supporting portion is received in the receiving chamber for being rotatable with the other one of the first shaft and the second shaft.
- the vane member is received in the receiving chamber.
- the vane member is provided integrally with the vane supporting portion. Pressure of working fluid, which flows into and out of pressure chambers of the receiving chamber, causes the vane member to rotate relative to the housing within a predetermined angle range.
- the vane member includes an axial hole that extends therethrough along the rotation axis.
- the limiting member is reciprocably received in the axial hole for limiting the vane member from rotating relative to the housing.
- the fitting hole is provided to one of the side walls of the housing for fitting with one end of the limiting member.
- the atmosphere communication hole is provided to the one of the side walls for communication with atmosphere. The fitting hole is communicated with atmosphere via the atmosphere communication hole.
- the limiting member limits the vane member from rotating relative to the housing when the one end of the limiting
- FIG. 1 is a cross-sectional view illustrating a valve timing adjusting apparatus according to the first embodiment of the present invention
- FIG. 2 is a cross-sectional view taken along line II-II in FIG. 1 ;
- FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2 ;
- FIG. 4 is a cross-sectional view illustrating the valve timing adjusting apparatus according to the first embodiment of the present invention in a state, where vane members are located at a full retard position;
- FIG. 5 is a cross-sectional view illustrating the valve timing adjusting apparatus according to the first embodiment of the present invention in a state, where the vane members are located at a full advance position;
- FIG. 6 is a cross-sectional view illustrating a valve timing adjusting apparatus according to the first modification of the present invention.
- FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. 6 ;
- FIG. 8 is a cross-sectional view taken along line VIII-VIII in FIG. 6 ;
- FIG. 9 is a cross-sectional view illustrating a valve timing adjusting apparatus according to the second modification of the present invention.
- FIG. 10 is a cross-sectional view taken along line X-X in FIG. 9 ;
- FIG. 11 is a cross-sectional view taken along line XI-XI in FIG. 9 .
- a valve timing adjusting apparatus according to the first embodiment of the present invention is shown in FIGS. 1 to 5 .
- a valve timing adjusting apparatus 10 is a hydraulic control apparatus that employs hydraulic oil as working fluid, and adjusts valve timing of an intake valve.
- the valve timing adjusting apparatus 10 includes a housing 11 and a vane rotor 50 .
- the housing 11 includes a front plate 20 as a side wall, a shoe housing 30 as a peripheral wall, and a chain sprocket 40 as another side wall.
- the front plate 20 , the shoe housing 30 , and the chain sprocket 40 are coaxially fixed with each other through a bolt 12 . Due to the above configuration, the front plate 20 and the chain sprocket 40 are coupled to both axial ends of the shoe housing 30 along a rotation axis.
- the shoe housing 30 , the front plate 20 , and the chain sprocket 40 define a receiving chamber 35 therebetween.
- the chain sprocket 40 is coupled to a crank shaft, which serves as a drive shaft (first shaft) of an engine (not shown), via a chain (not shown) such that a driving force is transmitted to the chain sprocket 40 for rotation of the chain sprocket 40 in time with or synchronously with the crank shaft.
- the driving force of the crank shaft is transmitted to a camshaft 70 , which serves as a driven shaft (second shaft), via the housing 11 .
- the camshaft 70 opens and closes an intake valve (not shown).
- the camshaft 70 actuates the intake valve for displacing the intake valve to an opening position and a closed position.
- the camshaft 70 is rotatably received in the chain sprocket 40 in a predetermined phase relationship relative to the chain sprocket 40 .
- the vane rotor 50 is received in the receiving chamber 35 , and contacts an axial end surface of the camshaft 70 along the rotation axis.
- the camshaft 70 and the vane rotor 50 are coaxially fixed with each other via a bolt 13 .
- the positioning of the vane rotor 50 relative to the camshaft 70 in a rotational direction is made through fitting a positioning pin 14 into the vane rotor 50 and the camshaft 70 .
- the above configuration allows the vane rotor 50 and the camshaft 70 to coaxially rotate relative to the housing 11 .
- the camshaft 70 , the housing 11 , and the vane rotor 50 clockwisely rotate when observed in a direction indicated by an arrow Z shown in FIG. 1 .
- the above clockwise rotational direction is defined as an advance direction of the camshaft 70 relative to the crank shaft.
- the shoe housing 30 of the housing 11 includes a tubular portion 31 , which has a tubular shape, and shoes 32 , 33 , 34 , which radially inwardly project from the tubular portion 31 .
- Each of the shoes 32 , 33 , 34 has a generally trapezoid shape, and the shoes 32 , 33 , 34 are arranged in generally equal intervals along a radially inner surface of the tubular portion 31 in the rotational direction.
- the vane rotor 50 includes a hub portion 51 , which serves as a vane supporting portion, and vanes 52 , 53 , 54 , which serves as vane members.
- the vanes 52 , 53 , 54 are arranged in generally equal intervals along a radially outer surface of the hub portion 51 in the rotational direction.
- the vanes 52 , 53 , 54 are integral with the hub portion 51 .
- the vane rotor 50 is received in the receiving chamber 35 such that the vane rotor 50 is rotatable relative to the housing 11 .
- Each of the vanes 52 , 53 , 54 is rotatably received in a corresponding vane receiving chamber 351 .
- the shoes 32 , 33 , 34 define three vane receiving chambers 351 in the receiving chamber 35 , and the vane receiving chambers 351 are arranged in the rotational direction within predetermined angle ranges.
- the shoes 32 , 33 , 34 define the three vane receiving chambers 351 in the receiving chamber 35 such that the vane receiving chambers 351 are arranged one after another in the rotational direction.
- each of the vane receiving chambers 351 circumferentially extends within the predetermined angle range.
- Each of the vanes 52 , 53 , 54 divides the corresponding vane receiving chamber 351 into a retard oil pressure chamber and an advance oil pressure chamber as pressure chambers.
- the shoe 32 and the vane 52 defines a retard oil pressure chamber 301 therebetween
- the shoe 33 and the vane 53 define a retard oil pressure chamber 302 therebetween
- the shoe 34 and the vane 54 define a retard oil pressure chamber 303 therebetween.
- the shoe 34 and the vane 52 define an advance oil pressure chamber 311 therebetween
- the shoe 32 and the vane 53 define an advance oil pressure chamber 312 therebetween
- the shoe 33 and the vane 54 define an advance oil pressure chamber 313 therebetween.
- a seal member 15 is provided between (a) each of the shoes 32 , 33 , 34 and (b) a corresponding part of the hub portion 51 , which part faces the shoe in the radial direction. Also, another seal member 15 is provided between (a) each of the vanes 52 , 53 , 54 and (b) a corresponding part of the tubular portion 31 of the shoe housing 30 , which part faces the vane in the radial direction.
- the seal members 15 are fitted into grooves provided at tip ends of the shoes 32 , 33 , 34 .
- the other seal members 15 are also fitted into other grooves provided at end portions of the vanes 52 , 53 , 54 opposite to the hub portion 51 .
- each seal member 15 biases each seal member 15 toward the radially outer wall of the hub portion 51 or the radially inner wall of the tubular portion 31 . Due to the above configuration, the seal members 15 fluid tightly keep the retard oil pressure chambers and the advance oil pressure chambers from each other. Thus, hydraulic oil is limited from leaking from one of the retard oil pressure chambers into adjacent one of the advance oil pressure chambers.
- the vane rotor 50 includes a hole 55 that is an axial hole extending through the vane 52 along the rotation axis or in a longitudinal direction.
- the hole 55 receives a stopper piston 80 and a spring 81 therein, and the stopper piston 80 serves as a limiting member.
- the stopper piston 80 has a generally hollow cylindrical shape, and is received in the hole 55 reciprocably displaceably in the longitudinal direction.
- the spring 81 has one axial end portion that contacts the chain sprocket 40 and another axial end portion that contacts the stopper piston 80 .
- the spring 81 gives a force that is applied in the longitudinal direction. Due to the above configuration, the spring 81 biases the stopper piston 80 toward the front plate 20 .
- the front plate 20 has a recess groove portion 21 at an end surface of the front plate 20 toward the vane rotor 50 , and the recess groove portion 21 receives a fitting ring 22 in a press fitted relation.
- the recess groove portion 21 is provided at a position generally intermediate between a full retard position and a full advance position.
- the full retard position and the full advance position are defined as maximum positions that the vane 52 is displaceable to when the vane rotor 50 rotates relative to the housing 11 , for example.
- the fitting ring 22 has a generally hollow cylindrical shape.
- the fitting ring 22 has a fitting hole 23 at a generally central position thereof, which hole 23 extends through the fitting ring 22 in the longitudinal direction. In other words, the fitting hole 23 is provided at a position generally intermediate between the full retard position and the full advance position.
- the stopper piston 80 is capable of being fitted with the fitting ring 22 by fitting one end of the stopper piston 80 into the fitting hole 23 .
- each of the stopper piston 80 and the fitting ring 22 has a fitting portion that is tapered.
- the stopper piston 80 has the fitting portion that is tapered such that the fitting portion becomes narrower toward the end compared with the other portion of the piston 80 , for example.
- the fitting ring 22 has the fitting portion that is tapered or is flared to have an enlarged inner diameter at the end, for example.
- the stopper piston 80 is capable of being smoothly fitted with the fitting ring 22 .
- An oil pressure chamber 82 is defined at an outer periphery of the stopper piston 80 and is supplied with hydraulic oil. The pressure of hydraulic oil is applied in a direction such that the stopper piston 80 gets out of the fitting ring 22 .
- the stopper piston 80 is brought into and is taken out of a fitted relation with the fitting ring 22 depending on a balance between (a) the force applied by the oil pressure chamber 82 and (b) the biasing force applied by the spring 81 .
- the recess groove portion 21 includes an atmosphere communication hole 24 that extends through the front plate 20 in a thickness direction of the front plate 20 or in the longitudinal direction. Due to the above configuration, the fitting hole 23 of the fitting ring 22 has an end portion opposite to the vane 52 , which end portion is communicated with atmosphere via the atmosphere communication hole 24 . In other words, the fitting hole 23 is exposed to atmosphere. It should be noted that the fitting hole 23 has another end portion toward the vane 52 , which end portion is communicated with the receiving chamber 35 .
- the atmosphere communication hole 24 has a diameter w 1 that is smaller than a diameter w 2 of a fitting end portion of the stopper piston 80 , which end portion is fitted with the fitting hole 23 .
- the diameter w 1 of the atmosphere communication hole 24 is smaller than a diameter of the fitting hole 23 .
- an annular step surface 25 is defined between the atmosphere communication hole 24 and the fitting hole 23 .
- an oblong groove portion 42 is formed at an end surface of the chain sprocket 40 toward the vane rotor 50 .
- the oblong groove portion 42 has a generally arc shape and is recessed by a predetermined depth d.
- the oblong groove portion 42 is provided with a pressure discharge hole 41 that extends through the chain sprocket 40 in the thickness direction of the chain sprocket 40 . Due to the above configuration, the hole 55 formed on the vane 52 is communicated with atmosphere via the oblong groove portion 42 and the pressure discharge hole 41 .
- the oblong groove portion 42 has the generally arc shape, even when the vane 52 is located at the full retard position as shown in FIG. 4 , the oblong groove portion 42 is communicated with the hole 55 . Also, even when the vane 52 is located at the full advance position as shown in FIG. 5 , the oblong groove portion 42 is communicated with the hole 55 . In other words, the hole 55 is communicated with atmosphere via the oblong groove portion 42 and the pressure discharge hole 41 regardless of the position of the vane 52 when the vane 52 is rotated relative to the housing 11 within the predetermined angle range defined between the full retard position and the full advance position. It should be noted that in FIGS. 2 , 4 , and 5 , the fitting hole 23 and the atmosphere communication hole 24 formed on the front plate 20 are indicated by dashed and double-dotted lines for more obvious indication.
- the fitting hole 23 is formed in a range generally intermediate between the full retard position and the full advance position.
- the full retard position and the full advance position are maximum movable positions, on which the vane 52 is capable of being located when the vane rotor 50 is rotated relative to the housing 11 .
- the fitting hole 23 is positioned within the movable range of the vane 52 .
- the oblong groove portion 42 is formed such that the oblong groove portion 42 is located within the movable range of the vane 52 .
- fitting hole 23 and the oblong groove portion 42 are always located at a position that correspondingly stays in a range within the outer edge of the vane 52 even when the vane 52 is displaced in a range between the full retard position shown in FIG. 4 and the full advance position shown in FIG. 5 by the rotation of the vane rotor 50 relative to the housing 11 .
- fitting hole 23 and the oblong groove portion 42 are always located at a position that overlaps with the vane 52 in the longitudinal direction even when the vane 52 is displaced in a range between the full retard position and the full advance position.
- the vane rotor 50 has an end surface 56 toward the front plate 20 , which surface 56 is fluid tightly slidable on the front plate 20 .
- the vane 52 has an end surface toward the front plate 20 , which surface is fluid tightly slidable on the front plate 20 .
- the fitting hole 23 is limited from being communicated with the retard oil pressure chamber 301 or the advance oil pressure chamber 311 , and thereby the leakage of hydraulic oil from the retard oil pressure chamber 301 or the advance oil pressure chamber 311 to atmosphere via the fitting hole 23 and the atmosphere communication hole 24 is reduced.
- the vane rotor 50 has an end surface 57 toward the chain sprocket 40 , which surface 57 is fluid tightly slidable on the chain sprocket 40 .
- the vane 52 has an end surface toward the chain sprocket 40 , which surface is fluid tightly slidable on the chain sprocket 40 . Therefore, the oblong groove portion 42 is limited from being communicated with the retard oil pressure chamber 301 or the advance oil pressure chamber 311 , and thereby the leakage of hydraulic oil from the retard oil pressure chamber 301 or the advance oil pressure chamber 311 to atmosphere via the oblong groove portion 42 and the pressure discharge hole 41 is reduced.
- a radially outer wall of the camshaft 70 is rotatably supported by a bearing 16 , and the radially outer wall of the camshaft 70 is provided with annular passages 71 , 72 , 73 .
- the camshaft 70 and the hub portion 51 define a passage 821 , three retard passages 305 , and three advance passages 315 therein.
- the passage 821 is connected with the annular passage 71
- the retard passages 305 is connected with the annular passage 72
- the advance passages 315 is connected with the annular passage 73 .
- the hub portion 51 of the vane rotor 50 defines a passage 822 therein.
- the passage 822 connects the passage 821 with the oil pressure chamber 82 .
- the annular passage 71 and the oil pressure chamber 82 are communicated with each other via the passages 821 , 822 .
- the hub portion 51 defines three retard passages 306 therein.
- the retard passages 306 connect the retard passages 305 with the corresponding retard oil pressure chambers.
- the annular passage 72 is communicated with each of the retard oil pressure chambers via the retard passages 305 , 306 .
- the hub portion 51 defines three advance passages 316 therein.
- the advance passages 316 connect the advance passages 315 with the corresponding advance oil pressure chambers. Due to the above configuration, the annular passage 73 is communicated with each of the advance oil pressure chambers via the advance passages 315 , 316 .
- the oil pressure chamber 82 is connected to an oil pump (not shown) and an oil tank (not shown) via the passages 822 , 821 , and the annular passage 71 .
- the oil pump feeds hydraulic oil pumped from the oil tank to the oil pressure chamber 82 via a control valve (not shown).
- a control valve not shown.
- the retard oil pressure chambers 301 , 302 , 303 are connected with the oil pump and the oil tank via the retard passages 306 , 305 , and the annular passage 72 .
- the advance oil pressure chambers 311 , 312 , 313 are connected with the oil pump and the oil tank via the advance passages 316 , 315 , and the annular passage 73 .
- the oil pump supplies hydraulic oil pumped from the oil tank to the retard oil pressure chambers 301 , 302 , 303 or the advance oil pressure chambers 311 , 312 , 313 via a switching valve (not shown).
- each retard oil pressure chamber and each advance oil pressure chamber are connected to the oil tank via the switching valve.
- hydraulic oil is supplied from the oil tank to one of (a) each retard oil pressure chamber and (b) each advance oil pressure chamber, and hydraulic oil is discharged to the oil tank from the other one of (a) each retard oil pressure chamber and each advance oil pressure chamber. Due to the above configuration, a relative rotational position of the vane rotor 50 relative to the housing 11 is changed depending on oil pressure balance, and the phase relation between the crank shaft (not shown) and the camshaft 70 is changed.
- the vane rotor 50 is connected with the front plate 20 , the rotation driving force is reliably transmitted to the camshaft 70 from the crank shaft. Also, even when positive and negative variable torques are generated to the camshaft 70 , the vane rotor 50 and the housing 11 are limited from generating vibration caused by the relative rotation, and thereby noise is limited from being generated.
- the operational state of the control valve (not shown) is switched such that hydraulic oil is fed to the oil pressure chamber 82 from the oil pump.
- hydraulic oil is fed to the oil pressure chamber 82 , and thereby the internal pressure in the oil pressure chamber 82 is increased, the stopper piston 80 gets out of the fitting hole 23 of the fitting ring 22 .
- the stopper piston 80 is taken out of the fitting hole 23 , the vane rotor 50 is disconnected from the front plate 20 , and thereby the vane rotor 50 becomes rotatable relative to the shoe housing 30 within the angle range defined between the full retard position and the full advance position.
- the operation of the engine is usually stopped in the above normal state, where the stopper piston 80 is fitted into the fitting hole 23 , or in other words, where the vane rotor 50 is limited from being rotated relative to the housing 11 , and thereby the engine is set ready for the restart.
- the operation may be stopped in a state, where the stopper piston 80 is not fitted into the fitting hole 23 , for example, when the engine is stopped unexpectedly.
- the stopper piston 80 is biased toward the front plate 20 by the biasing force of the spring 81 .
- variable torque is generated to the camshaft 70 . Due to the above, the vane rotor 50 fluctuates in the retard direction and in the advance direction.
- the stopper piston 80 which is biased toward the front plate 20 , is fitted into the fitting hole 23 .
- the vane rotor 50 is connected with the front plate 20 , and thereby the relative rotation of the vane rotor 50 relative to the front plate 20 , in other words, to the housing 11 is limited.
- a limiting member is reciprocably displaceably received in an axial hole that includes a space defined by (a) an end portion of the limiting member opposite to the fitting hole and (b) the side wall of the housing.
- the fitting hole 23 does not store hydraulic oil.
- the fitting hole which otherwise is required to push remained hydraulic oil toward the oil passage when the fitting hole were not exposed to atmosphere in the conventional art, is not required to push the remained hydraulic oil in the fitting hole 23 .
- the stopper piston 80 is easily fitted into the fitting hole 23 .
- responsivity of the stopper piston 80 is improved, and thereby the relative rotation of the vane rotor 50 relative to the housing 11 is easily and highly accurately limited due to the stopper piston 80 .
- responsivity of the valve timing adjusting apparatus 10 is effectively improved, and thereby the phase of the camshaft 70 is highly accurately controlled.
- the atmosphere communication hole 24 has the diameter w 1 that is smaller than the diameter w 2 of the end portion of the stopper piston 80 , which end portion is fitted into the fitting hole 23 .
- the diameter w 1 of the atmosphere communication hole 24 is smaller than the diameter of the fitting hole 23 .
- the annular step surface 25 is formed between the atmosphere communication hole 24 and the fitting hole 23 .
- the chain sprocket 40 is provided with the pressure discharge hole 41 that is communicated with atmosphere.
- the hole 55 in which the stopper piston 80 is reciprocably received, is communicated with atmosphere via the pressure discharge hole 41 .
- pressure in a space in the hole 55 defined between the stopper piston 80 and the chain sprocket 40 is kept similar to the atmospheric pressure. Due to the above configuration, the stopper piston 80 is smoothly reciprocably displaceable.
- the hole 55 is communicated with atmosphere via the oblong groove portion 42 and the pressure discharge hole 41 regardless of the position of the vane 52 provided that the vane 52 is rotated relative to the housing 11 within the predetermined angle range.
- the stopper piston 80 is capable of being smoothly reciprocably displaceable regardless of the position of the vane 52 .
- responsivity of the stopper piston 80 is effectively improved, and thereby the relative rotation of the vane rotor 50 relative to the housing 11 is easily and highly accurately limited by the stopper piston 80 .
- a valve timing adjusting apparatus according to the first modification of the present invention will be described with reference to FIGS. 6 to 8 . It should be noted that similar components of the valve timing adjusting apparatus of the present modification, which are similar to the components of the valve timing adjusting apparatus of the first embodiment, will be indicated by the same numerals, and explanation thereof will be omitted.
- the first modification is different from the first embodiment in that the end surface 56 and the end surface 57 of the vane rotor 50 have a recess and a seal portion, and in that the chain sprocket 40 does not include the oblong groove portion 42 .
- the vane 52 has a recess 521 and a seal portion 522 on the end surface 56 that faces the front plate 20 of the vane rotor 50 .
- the recess 521 is formed by a recess groove 523 on the end surface 56 .
- the seal portion 522 extends from the hub portion 51 along the outer edge of the vane 52 such that the seal portion 522 has a U shape, and the seal portion 522 is positioned to surround the recess 521 together with the hub portion 51 .
- the seal portion 522 is positioned around three ways or three sides of the seal members 15 .
- the seal portion 522 contacts the front plate 20 such that the seal portion 522 is fluid tightly slidable on the front plate 20 . Due to the above configuration, leakage of hydraulic oil between the retard oil pressure chamber 301 and the advance oil pressure chamber 311 is reduced.
- the vane 53 has a recess 531 and a seal portion 532 on the end surface 56
- the vane 54 has a recess 541 and a seal portion 542 .
- the seal portions 532 , 542 contact the front plate 20 such that the seal portions 532 , 542 are fluid tightly slidable on the front plate 20 . Due to the above configuration, leakage of hydraulic oil between the retard oil pressure chamber 302 and the advance oil pressure chamber 312 , and leakage of hydraulic oil between the retard oil pressure chamber 303 and the advance oil pressure chamber 313 are reduced.
- the vane 52 has a recess 524 and a seal portion 525 on the end surface 57 that faces the chain sprocket 40 of the vane rotor 50 .
- the recess 524 is formed by providing a recess groove 526 on the end surface 57 .
- the seal portion 525 extends from the hub portion 51 along the outer edge of the vane 52 to have a U shape, and the seal portion 525 is positioned to surround the recess 524 together with the hub portion 51 .
- the seal portion 525 is positioned around the three sides of the seal members 15 . In other words, the seal portion 525 is shaped to face the three sides of the seal members 15 .
- the seal portion 525 contacts the chain sprocket 40 such that the seal portion 525 is fluid tightly slidable on the chain sprocket 40 . Due to the above configuration, leakage of hydraulic oil between the retard oil pressure chamber 301 and the advance oil pressure chamber 311 is reduced.
- the vane 53 has a recess 534 and a seal portion 535 on the end surface 571 and the vane 54 has a recess 544 and a seal portion 545 on the end surface 57 .
- the seal portions 535 , 545 contact the chain sprocket 40 such that the seal portions 535 , 545 are fluid tightly slidable on the chain sprocket 40 . Due to the above configuration, leakage of hydraulic oil between the retard oil pressure chamber 302 and the advance oil pressure chamber 312 , and leakage of hydraulic oil between the retard oil pressure chamber 303 and the advance oil pressure chamber 313 are reduced.
- the fitting hole 23 is communicated with atmosphere via the atmosphere communication hole 24 .
- the chain sprocket 40 does not include the oblong groove portion differently from the first embodiment, the chain sprocket 40 include the pressure discharge hole 41 that extends through the chain sprocket 40 in the thickness direction of the chain sprocket 40 similar to the first embodiment. Because the vane 52 has the recess 524 on the end surface 57 , the pressure discharge hole 41 is communicated with the hole 55 via the recess 524 even when the vane 52 is located at one of the full retard position and the full advance position.
- the hole 55 is communicated with atmosphere via the recess 524 and the pressure discharge hole 41 regardless of the position of the vane 52 when the vane 52 is rotated relative to the housing 11 within the predetermined angle range defined between the full retard position and the full advance position.
- the fitting hole 23 and the pressure discharge hole 41 are formed at a position generally intermediate between the full retard position and the full advance position.
- the above full retard and advance positions correspond to the maximum displaceable positions that the vane 52 is displaceable to when the vane rotor 50 is rotated relative to the housing 11 .
- the fitting hole 23 and the pressure discharge hole 41 are always located a position correspondingly to the inward of the outer edge of the vane 52 when the vane 52 is located at any position between the full retard position and the full advance position.
- the fitting hole 23 and the pressure discharge hole 41 are always located to overlap with the vane 52 in the longitudinal direction when the vane 52 is located at any position between the full retard position and the full advance position, for example.
- the seal portion 522 of the vane 52 contacts the front plate 20 such that the seal portion 522 is fluid tightly slidable on the front plate 20 .
- the fitting hole 23 is limited from being communicated with the retard oil pressure chamber 301 or the advance oil pressure chamber 311 , and thereby leakage of hydraulic oil from the retard oil pressure chamber 301 or from the advance oil pressure chamber 311 to atmosphere via the fitting hole 23 and via the atmosphere communication hole 24 is reduced.
- the seal portion 525 of the vane 52 contacts the chain sprocket 40 such that the seal portion 525 is fluid tightly slidable on the chain sprocket 40 .
- the pressure discharge hole 41 is limited from being communicated with the retard oil pressure chamber 301 or the advance oil pressure chamber 311 , and thereby leakage of hydraulic oil from the retard oil pressure chamber 301 or from the advance oil pressure chamber 311 to atmosphere via the pressure discharge hole 41 is reduced.
- the vanes 52 , 53 , 54 are provided with the recesses 521 , 531 , 541 and the recesses 524 , 534 , 544 , respectively.
- the vanes 52 , 53 , 54 slide on the front plate 20 through the seal portions 522 , 532 , 542
- the vanes 52 , 53 , 54 slide on the chain sprocket 40 through the seal portions 525 , 535 , 545 .
- the vanes 52 , 53 , 54 slide on the front plate 20 and the chain sprocket 40 through slidable surfaces having substantially small areas.
- hydraulic oil may generate small resistance, and thereby the vane rotor 50 is easily rotated relative to the housing 11 .
- degree of viscosity of hydraulic oil tends to be increased at the low-temperature situation, such as when the engine is started.
- the fitting hole 23 is exposed to atmosphere via the atmosphere communication hole 24 , and the hole 55 is exposed to atmosphere via the pressure discharge hole 41 .
- responsivity of the stopper piston 80 is effectively improved.
- valve timing adjusting apparatus of the second modification of the present invention will be described with reference to FIGS. 9 to 11 . It should be noted that similar components of valve timing adjusting apparatus of the present example, which are similar to the components of the valve timing adjusting apparatus of the first modification, will be indicated by the same numerals, and explanation thereof will be omitted. Recesses and seal portions of the vanes 53 , 54 of the second modification are different in shape from those in the first modification.
- the vane 53 has recesses 631 and a seal portion 632 on the end surface 56 .
- the seal portion 632 radially outwardly extends from the hub portion 51 to have an I shape.
- the recesses 631 are formed by providing recess grooves 633 on both ends of the seal portion 632 .
- the seal portion 632 is positioned around the three sides of the seal members 15 . The seal portion 632 contacts the front plate 20 such that the seal portion 632 is fluid tightly slidable on the front plate 20 . Due to the above configuration, leakage of hydraulic oil between the retard oil pressure chamber 302 and the advance oil pressure chamber 312 is reduced.
- the vane 54 has recesses 641 and a seal portion 642 on the end surface 56 .
- the seal portion 642 contacts the front plate 20 such that the seal portion 642 is fluid tightly slidable on the front plate 20 . Due to the above configuration, leakage of hydraulic oil between the retard oil pressure chamber 303 and the advance oil pressure chamber 313 is reduced.
- the vane 53 has recesses 634 and a seal portion 635 on the end surface 57 .
- the seal portion 635 radially outwardly extends from the hub portion 51 to have an I shape.
- the recesses 634 are formed by providing recess grooves 636 on both ends of the seal portion 635 .
- the seal portion 635 is positioned around the three sides of the seal members 15 .
- the seal portion 635 contacts the chain sprocket 40 such that the seal portion 635 is fluid tightly slidable on the chain sprocket 40 . Due to the above configuration, leakage of hydraulic oil between the retard oil pressure chamber 302 and the advance oil pressure chamber 312 is reduced.
- the vane 54 has recesses 644 and a seal portion 645 on the end surface 57 .
- the seal portion 645 contacts the chain sprocket 40 such that the seal portion 645 is fluid tightly slidable on the chain sprocket 40 . Due to the above configuration, leakage of hydraulic oil between the retard oil pressure chamber 303 and the advance oil pressure chamber 313 is reduced.
- each vane slides on the internal wall surface of the housing 11 through the seal portion provided to the vane.
- the vane slides on the internal wall surface of the housing 11 through slidable surfaces having substantially small areas.
- the areas of the slidable surfaces, through which the vane slides on the internal wall surface of the housing 11 are smaller compared with those in the first modification.
- the oblong groove portion which is communicated with the pressure discharge hole, has a generally arc shape.
- the oblong groove portion is not limited to having the arc shape.
- the oblong groove portion may have any shape.
- the oblong groove portion may have any depth.
- each of the stopper piston and the fitting hole of the fitting ring may have a straight shape instead of the tapered shape.
- the front plate is provided with the fitting ring, and the stopper piston is fitted into the fitting hole formed on the fitting ring.
- a fitting ring may be provided on the chain sprocket located opposite to the front plate, and the stopper piston may be fitted to the chain sprocket.
- the pressure discharge hole may be formed on the front plate instead of the chain sprocket.
- the fitting ring is provided on the inner wall of the housing, and the stopper piston is fitted into the fitting hole formed on the fitting ring.
- the fitting ring may not be formed on the inner wall of the housing.
- a fitting hole which is communicated with atmosphere, may be formed on the housing such that the stopper piston is fitted into the above fitting hole.
- valve timing adjusting apparatus is applied to the intake valve of the engine.
- valve timing adjusting apparatus of the present invention may be applicable to an exhaust valve.
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- Valve Device For Special Equipments (AREA)
Abstract
A valve timing adjusting apparatus includes a housing, a vane supporting portion, a vane member, a limiting member, a fitting hole, and an atmosphere communication hole. The housing is rotatable about a rotation axis. The housing includes a peripheral wall and side walls to define a receiving chamber. The vane member is received integrally with the vane supporting portion in the receiving chamber. The vane member defines an axial hole therein. The limiting member is reciprocably received in the axial hole. The fitting hole and the atmosphere communication hole are provided to one of the side walls. The fitting hole is communicated with atmosphere via the communication hole. The limiting member limits the vane member from rotating relative to the housing when one end of the limiting member is fitted with the fitting hole.
Description
- This application is based on and incorporates herein by reference Japanese Patent Application No. 2007-290656 filed on Nov. 8, 2007 and Patent Application No. 2008-238613 filed on Sep. 17, 2008.
- 1. Field of the Invention
- The present invention relates to a valve timing adjusting apparatus for changing opening and closing timing of at least one of an intake valve and an exhaust valve for an internal combustion engine or an engine in accordance with an operational condition.
- 2. Description of Related Art
- Conventionally, there is known a vane-type valve timing adjusting apparatus, which drives a camshaft via a timing pulley of a housing rotatable in time with a crank shaft of the engine, and via a chain sprocket. The above valve timing adjusting apparatus controls a phase relationship between the crank shaft and the camshaft using pressure of hydraulic oil that flows into an advance oil pressure chamber and a retard oil pressure chamber, which serve as pressure chambers (see, for example, JP-A-2003-201810 corresponding to US 2003/0121485).
- In the above vane-type valve timing adjusting apparatus, because a stopper piston provided to a vane rotor is usually fitted with a fitting hole provided to the housing at the start of the engine, the vane rotor is limited from rotating relative to the housing. The above configuration is made to attempt reliable transmission of the driving force from the crank shaft to the camshaft immediately after the start of the engine, and to attempt the reduction of the noise due to the vibration caused by the rotation of the vane rotor relative to the housing.
- At the time of unexpected stop of the engine, the operation of the engine may stop in a state, where the stopper piston is not fitted with the fitting hole of the housing. In the above case, at the restart of the engine in the next operation, it is required that variable torque of the camshaft be used to fluctuate the vane rotor such that the stopper piston is brought into a fitted relation with the fitting hole of the housing, and thereby the relative rotation of the vane rotor relative to the housing is limited.
- In the conventional valve timing adjusting apparatus, the fitting hole of the housing is usually filled with hydraulic oil. Thus, when the stopper piston is brought into the fitted relation with the fitting hole, the stopper piston pushes back hydraulic oil in the fitting hole toward an oil passage. However, in a case, where the stopper piston has a tip end portion having a diameter larger than a diameter of the oil passage, pressure loss caused by the pushing of hydraulic oil by the stopper piston during the fitting of the stopper piston is large, and thereby response of the stopper piston speed is reduced. For example, in a case of the stopper piston that has a large tip end portion as shown in JP-A-2003-201810, the responsivity of stopper piston may remarkably deteriorate specifically when temperature is low, such as at the start of the engine, in which a degree of viscosity of hydraulic oil is large.
- The present invention is made in view of the above disadvantages. Thus, it is an objective of the present invention to address at least one of the above disadvantages.
- To achieve the objective of the present invention, there is provided a valve timing adjusting apparatus that is provided to a driving force transmission system for transmitting a driving force from a first shaft of an internal combustion engine to a second shaft that actuates at least one of an intake valve and an exhaust valve, wherein the valve timing adjusting apparatus adjusts opening and closing timing of the at least one of the intake valve and the exhaust valve. The valve timing adjusting apparatus includes a housing, a vane supporting portion, a vane member, a limiting member, a fitting hole, and an atmosphere communication hole. The housing is rotatable about a rotation axis with one of the first shaft and the second shaft. The housing includes a peripheral wall and side walls that are connected to both axial ends of the peripheral wall along the rotation axis. The housing defines a receiving chamber by the peripheral wall and the side walls. The vane supporting portion is received in the receiving chamber for being rotatable with the other one of the first shaft and the second shaft. The vane member is received in the receiving chamber. The vane member is provided integrally with the vane supporting portion. Pressure of working fluid, which flows into and out of pressure chambers of the receiving chamber, causes the vane member to rotate relative to the housing within a predetermined angle range. The vane member includes an axial hole that extends therethrough along the rotation axis. The limiting member is reciprocably received in the axial hole for limiting the vane member from rotating relative to the housing. The fitting hole is provided to one of the side walls of the housing for fitting with one end of the limiting member. The atmosphere communication hole is provided to the one of the side walls for communication with atmosphere. The fitting hole is communicated with atmosphere via the atmosphere communication hole. The limiting member limits the vane member from rotating relative to the housing when the one end of the limiting member is fitted with the fitting hole.
- The invention, together with additional objectives, features and advantages thereof, will be best understood from the following description, the appended claims and the accompanying drawings in which:
-
FIG. 1 is a cross-sectional view illustrating a valve timing adjusting apparatus according to the first embodiment of the present invention; -
FIG. 2 is a cross-sectional view taken along line II-II inFIG. 1 ; -
FIG. 3 is a cross-sectional view taken along line III-III inFIG. 2 ; -
FIG. 4 is a cross-sectional view illustrating the valve timing adjusting apparatus according to the first embodiment of the present invention in a state, where vane members are located at a full retard position; -
FIG. 5 is a cross-sectional view illustrating the valve timing adjusting apparatus according to the first embodiment of the present invention in a state, where the vane members are located at a full advance position; -
FIG. 6 is a cross-sectional view illustrating a valve timing adjusting apparatus according to the first modification of the present invention; -
FIG. 7 is a cross-sectional view taken along line VII-VII inFIG. 6 ; -
FIG. 8 is a cross-sectional view taken along line VIII-VIII inFIG. 6 ; -
FIG. 9 is a cross-sectional view illustrating a valve timing adjusting apparatus according to the second modification of the present invention; -
FIG. 10 is a cross-sectional view taken along line X-X inFIG. 9 ; and -
FIG. 11 is a cross-sectional view taken along line XI-XI inFIG. 9 . - A valve timing adjusting apparatus according to the first embodiment of the present invention is shown in
FIGS. 1 to 5 . A valvetiming adjusting apparatus 10 is a hydraulic control apparatus that employs hydraulic oil as working fluid, and adjusts valve timing of an intake valve. - As shown in
FIG. 1 , the valvetiming adjusting apparatus 10 includes ahousing 11 and avane rotor 50. Thehousing 11 includes afront plate 20 as a side wall, a shoe housing 30 as a peripheral wall, and a chain sprocket 40 as another side wall. Thefront plate 20, the shoe housing 30, and thechain sprocket 40 are coaxially fixed with each other through abolt 12. Due to the above configuration, thefront plate 20 and thechain sprocket 40 are coupled to both axial ends of theshoe housing 30 along a rotation axis. Thus, the shoe housing 30, thefront plate 20, and thechain sprocket 40 define a receivingchamber 35 therebetween. Thechain sprocket 40 is coupled to a crank shaft, which serves as a drive shaft (first shaft) of an engine (not shown), via a chain (not shown) such that a driving force is transmitted to thechain sprocket 40 for rotation of thechain sprocket 40 in time with or synchronously with the crank shaft. - The driving force of the crank shaft is transmitted to a
camshaft 70, which serves as a driven shaft (second shaft), via thehousing 11. Thecamshaft 70 opens and closes an intake valve (not shown). For example, thecamshaft 70 actuates the intake valve for displacing the intake valve to an opening position and a closed position. Thecamshaft 70 is rotatably received in thechain sprocket 40 in a predetermined phase relationship relative to thechain sprocket 40. - The
vane rotor 50 is received in thereceiving chamber 35, and contacts an axial end surface of thecamshaft 70 along the rotation axis. Thecamshaft 70 and thevane rotor 50 are coaxially fixed with each other via abolt 13. The positioning of thevane rotor 50 relative to thecamshaft 70 in a rotational direction is made through fitting apositioning pin 14 into thevane rotor 50 and thecamshaft 70. The above configuration allows thevane rotor 50 and thecamshaft 70 to coaxially rotate relative to thehousing 11. Thecamshaft 70, thehousing 11, and thevane rotor 50 clockwisely rotate when observed in a direction indicated by an arrow Z shown inFIG. 1 . In the present embodiment, the above clockwise rotational direction is defined as an advance direction of thecamshaft 70 relative to the crank shaft. - As shown in
FIG. 2 , theshoe housing 30 of thehousing 11 includes atubular portion 31, which has a tubular shape, and shoes 32, 33, 34, which radially inwardly project from thetubular portion 31. Each of theshoes shoes tubular portion 31 in the rotational direction. - The
vane rotor 50 includes ahub portion 51, which serves as a vane supporting portion, andvanes vanes hub portion 51 in the rotational direction. Thevanes hub portion 51. Thevane rotor 50 is received in the receivingchamber 35 such that thevane rotor 50 is rotatable relative to thehousing 11. Each of thevanes vane receiving chamber 351. Theshoes vane receiving chambers 351 in the receivingchamber 35, and thevane receiving chambers 351 are arranged in the rotational direction within predetermined angle ranges. In other words, theshoes vane receiving chambers 351 in the receivingchamber 35 such that thevane receiving chambers 351 are arranged one after another in the rotational direction. Also, each of thevane receiving chambers 351 circumferentially extends within the predetermined angle range. - Each of the
vanes vane receiving chamber 351 into a retard oil pressure chamber and an advance oil pressure chamber as pressure chambers. In other words, theshoe 32 and thevane 52 defines a retardoil pressure chamber 301 therebetween, theshoe 33 and thevane 53 define a retardoil pressure chamber 302 therebetween, and theshoe 34 and thevane 54 define a retardoil pressure chamber 303 therebetween. Also, theshoe 34 and thevane 52 define an advanceoil pressure chamber 311 therebetween, theshoe 32 and thevane 53 define an advanceoil pressure chamber 312 therebetween, and theshoe 33 and thevane 54 define an advanceoil pressure chamber 313 therebetween. - A
seal member 15 is provided between (a) each of theshoes hub portion 51, which part faces the shoe in the radial direction. Also, anotherseal member 15 is provided between (a) each of thevanes tubular portion 31 of theshoe housing 30, which part faces the vane in the radial direction. Theseal members 15 are fitted into grooves provided at tip ends of theshoes other seal members 15 are also fitted into other grooves provided at end portions of thevanes hub portion 51. For example, spring or other resilient member biases eachseal member 15 toward the radially outer wall of thehub portion 51 or the radially inner wall of thetubular portion 31. Due to the above configuration, theseal members 15 fluid tightly keep the retard oil pressure chambers and the advance oil pressure chambers from each other. Thus, hydraulic oil is limited from leaking from one of the retard oil pressure chambers into adjacent one of the advance oil pressure chambers. - As shown in
FIG. 1 , thevane rotor 50 includes ahole 55 that is an axial hole extending through thevane 52 along the rotation axis or in a longitudinal direction. Thehole 55 receives astopper piston 80 and aspring 81 therein, and thestopper piston 80 serves as a limiting member. Thestopper piston 80 has a generally hollow cylindrical shape, and is received in thehole 55 reciprocably displaceably in the longitudinal direction. Thespring 81 has one axial end portion that contacts thechain sprocket 40 and another axial end portion that contacts thestopper piston 80. Thespring 81 gives a force that is applied in the longitudinal direction. Due to the above configuration, thespring 81 biases thestopper piston 80 toward thefront plate 20. - The
front plate 20 has arecess groove portion 21 at an end surface of thefront plate 20 toward thevane rotor 50, and therecess groove portion 21 receives afitting ring 22 in a press fitted relation. Therecess groove portion 21 is provided at a position generally intermediate between a full retard position and a full advance position. The full retard position and the full advance position are defined as maximum positions that thevane 52 is displaceable to when thevane rotor 50 rotates relative to thehousing 11, for example. Thefitting ring 22 has a generally hollow cylindrical shape. Thefitting ring 22 has afitting hole 23 at a generally central position thereof, whichhole 23 extends through thefitting ring 22 in the longitudinal direction. In other words, thefitting hole 23 is provided at a position generally intermediate between the full retard position and the full advance position. Thestopper piston 80 is capable of being fitted with thefitting ring 22 by fitting one end of thestopper piston 80 into thefitting hole 23. - Each of the
stopper piston 80 and thefitting ring 22 has a fitting portion that is tapered. In other words, thestopper piston 80 has the fitting portion that is tapered such that the fitting portion becomes narrower toward the end compared with the other portion of thepiston 80, for example. Also, thefitting ring 22 has the fitting portion that is tapered or is flared to have an enlarged inner diameter at the end, for example. Thus, thestopper piston 80 is capable of being smoothly fitted with thefitting ring 22. Anoil pressure chamber 82 is defined at an outer periphery of thestopper piston 80 and is supplied with hydraulic oil. The pressure of hydraulic oil is applied in a direction such that thestopper piston 80 gets out of thefitting ring 22. Thestopper piston 80 is brought into and is taken out of a fitted relation with thefitting ring 22 depending on a balance between (a) the force applied by theoil pressure chamber 82 and (b) the biasing force applied by thespring 81. - The
recess groove portion 21 includes anatmosphere communication hole 24 that extends through thefront plate 20 in a thickness direction of thefront plate 20 or in the longitudinal direction. Due to the above configuration, thefitting hole 23 of thefitting ring 22 has an end portion opposite to thevane 52, which end portion is communicated with atmosphere via theatmosphere communication hole 24. In other words, thefitting hole 23 is exposed to atmosphere. It should be noted that thefitting hole 23 has another end portion toward thevane 52, which end portion is communicated with the receivingchamber 35. - As shown in
FIG. 3 , theatmosphere communication hole 24 has a diameter w1 that is smaller than a diameter w2 of a fitting end portion of thestopper piston 80, which end portion is fitted with thefitting hole 23. In other words, the diameter w1 of theatmosphere communication hole 24 is smaller than a diameter of thefitting hole 23. Due to the above configuration, anannular step surface 25 is defined between theatmosphere communication hole 24 and thefitting hole 23. Thus, when thestopper piston 80 is displaced in a direction for fitting with thefitting hole 23, thestopper piston 80 contacts thestep surface 25. - As shown in
FIGS. 2 and 3 , anoblong groove portion 42 is formed at an end surface of thechain sprocket 40 toward thevane rotor 50. Theoblong groove portion 42 has a generally arc shape and is recessed by a predetermined depth d. Theoblong groove portion 42 is provided with apressure discharge hole 41 that extends through thechain sprocket 40 in the thickness direction of thechain sprocket 40. Due to the above configuration, thehole 55 formed on thevane 52 is communicated with atmosphere via theoblong groove portion 42 and thepressure discharge hole 41. - Because the
oblong groove portion 42 has the generally arc shape, even when thevane 52 is located at the full retard position as shown inFIG. 4 , theoblong groove portion 42 is communicated with thehole 55. Also, even when thevane 52 is located at the full advance position as shown inFIG. 5 , theoblong groove portion 42 is communicated with thehole 55. In other words, thehole 55 is communicated with atmosphere via theoblong groove portion 42 and thepressure discharge hole 41 regardless of the position of thevane 52 when thevane 52 is rotated relative to thehousing 11 within the predetermined angle range defined between the full retard position and the full advance position. It should be noted that inFIGS. 2 , 4, and 5, thefitting hole 23 and theatmosphere communication hole 24 formed on thefront plate 20 are indicated by dashed and double-dotted lines for more obvious indication. - As above, the
fitting hole 23 is formed in a range generally intermediate between the full retard position and the full advance position. The full retard position and the full advance position are maximum movable positions, on which thevane 52 is capable of being located when thevane rotor 50 is rotated relative to thehousing 11. In other words, thefitting hole 23 is positioned within the movable range of thevane 52. Also, theoblong groove portion 42 is formed such that theoblong groove portion 42 is located within the movable range of thevane 52. Thus, thefitting hole 23 and theoblong groove portion 42 are always located at a position that correspondingly stays in a range within the outer edge of thevane 52 even when thevane 52 is displaced in a range between the full retard position shown inFIG. 4 and the full advance position shown inFIG. 5 by the rotation of thevane rotor 50 relative to thehousing 11. In other words,fitting hole 23 and theoblong groove portion 42 are always located at a position that overlaps with thevane 52 in the longitudinal direction even when thevane 52 is displaced in a range between the full retard position and the full advance position. - As shown in
FIG. 1 , thevane rotor 50 has anend surface 56 toward thefront plate 20, which surface 56 is fluid tightly slidable on thefront plate 20. In other words, thevane 52 has an end surface toward thefront plate 20, which surface is fluid tightly slidable on thefront plate 20. Thus, thefitting hole 23 is limited from being communicated with the retardoil pressure chamber 301 or the advanceoil pressure chamber 311, and thereby the leakage of hydraulic oil from the retardoil pressure chamber 301 or the advanceoil pressure chamber 311 to atmosphere via thefitting hole 23 and theatmosphere communication hole 24 is reduced. - Also, similarly, the
vane rotor 50 has anend surface 57 toward thechain sprocket 40, which surface 57 is fluid tightly slidable on thechain sprocket 40. In other words, thevane 52 has an end surface toward thechain sprocket 40, which surface is fluid tightly slidable on thechain sprocket 40. Therefore, theoblong groove portion 42 is limited from being communicated with the retardoil pressure chamber 301 or the advanceoil pressure chamber 311, and thereby the leakage of hydraulic oil from the retardoil pressure chamber 301 or the advanceoil pressure chamber 311 to atmosphere via theoblong groove portion 42 and thepressure discharge hole 41 is reduced. - As shown in
FIG. 1 , a radially outer wall of thecamshaft 70 is rotatably supported by abearing 16, and the radially outer wall of thecamshaft 70 is provided withannular passages camshaft 70 and thehub portion 51 define apassage 821, threeretard passages 305, and threeadvance passages 315 therein. Thepassage 821 is connected with theannular passage 71, theretard passages 305 is connected with theannular passage 72, and theadvance passages 315 is connected with theannular passage 73. - As shown in
FIG. 2 , thehub portion 51 of thevane rotor 50 defines apassage 822 therein. Thepassage 822 connects thepassage 821 with theoil pressure chamber 82. Due to the above configuration, theannular passage 71 and theoil pressure chamber 82 are communicated with each other via thepassages hub portion 51 defines threeretard passages 306 therein. Also, theretard passages 306 connect theretard passages 305 with the corresponding retard oil pressure chambers. Due to the above configuration, theannular passage 72 is communicated with each of the retard oil pressure chambers via theretard passages hub portion 51 defines threeadvance passages 316 therein. Theadvance passages 316 connect theadvance passages 315 with the corresponding advance oil pressure chambers. Due to the above configuration, theannular passage 73 is communicated with each of the advance oil pressure chambers via theadvance passages - The
oil pressure chamber 82 is connected to an oil pump (not shown) and an oil tank (not shown) via thepassages annular passage 71. The oil pump feeds hydraulic oil pumped from the oil tank to theoil pressure chamber 82 via a control valve (not shown). When theoil pressure chamber 82 is fed with hydraulic oil, internal pressure in theoil pressure chamber 82 is increased, and thereby thestopper piston 80 gets out of or released from thefitting hole 23 of thefitting ring 22. Due to the above, thevane rotor 50 is disconnected from thefront plate 20, and thevane rotor 50 is allowed to rotate relative to thehousing 11. - When hydraulic oil in the
oil pressure chamber 82 is discharged to the oil tank via the control valve, internal pressure in theoil pressure chamber 82 is reduced. As a result, thestopper piston 80 is biased toward thefront plate 20 due to the biasing force of thespring 81. - The retard
oil pressure chambers retard passages annular passage 72. Also, the advanceoil pressure chambers advance passages annular passage 73. The oil pump supplies hydraulic oil pumped from the oil tank to the retardoil pressure chambers oil pressure chambers - Also, each retard oil pressure chamber and each advance oil pressure chamber are connected to the oil tank via the switching valve. By switching the switching valve, hydraulic oil is supplied from the oil tank to one of (a) each retard oil pressure chamber and (b) each advance oil pressure chamber, and hydraulic oil is discharged to the oil tank from the other one of (a) each retard oil pressure chamber and each advance oil pressure chamber. Due to the above configuration, a relative rotational position of the
vane rotor 50 relative to thehousing 11 is changed depending on oil pressure balance, and the phase relation between the crank shaft (not shown) and thecamshaft 70 is changed. - Next, one example of an operation of the present embodiment during a normal operation between the start of the engine and the stop of the engine will be described.
- As shown in
FIG. 2 , when the engine is started, hydraulic oil from the oil pump (not shown) has not yet been fed to each retard oil pressure chamber, each advance oil pressure chamber, and theoil pressure chamber 82, and thevane rotor 50 is located at a position generally intermediate between the full retard position and the full advance position relative to theshoe housing 30. Because thestopper piston 80 is fitted with thefitting hole 23 of thefitting ring 22 in the above state, thevane rotor 50 is connected with thefront plate 20, and thereby thevane rotor 50 is limited from being rotated relative to thefront plate 20. Thus, thevane rotor 50 rotates with thefront plate 20 or, in other words, rotates with thehousing 11. Because thevane rotor 50 is connected with thefront plate 20, the rotation driving force is reliably transmitted to thecamshaft 70 from the crank shaft. Also, even when positive and negative variable torques are generated to thecamshaft 70, thevane rotor 50 and thehousing 11 are limited from generating vibration caused by the relative rotation, and thereby noise is limited from being generated. - During the normal operation of the engine, the operational state of the control valve (not shown) is switched such that hydraulic oil is fed to the
oil pressure chamber 82 from the oil pump. When hydraulic oil is fed to theoil pressure chamber 82, and thereby the internal pressure in theoil pressure chamber 82 is increased, thestopper piston 80 gets out of thefitting hole 23 of thefitting ring 22. When thestopper piston 80 is taken out of thefitting hole 23, thevane rotor 50 is disconnected from thefront plate 20, and thereby thevane rotor 50 becomes rotatable relative to theshoe housing 30 within the angle range defined between the full retard position and the full advance position. In the above case, when hydraulic oil is fed to the retardoil pressure chambers oil pressure chambers vanes vane rotor 50 is rotated in the retard direction. Also, when hydraulic oil is fed to the advanceoil pressure chambers oil pressure chambers vanes vane rotor 50 is rotated in the advance direction. - As above, hydraulic oil supplied from the oil pump to each retard oil pressure chamber or each advance oil pressure chamber controls the relative rotation of the
vane rotor 50 relative to thehousing 11. Due to the above configuration, the phase relation between the crank shaft (not shown) and thecamshaft 70 is changed. - When the engine is commanded to stop in a state, where the
stopper piston 80 is located on a side of the generally intermediate position in the advance direction, or in other words, thestopper piston 80 is located on a side of a formation position, on which thefitting hole 23 is formed, in the advance direction, hydraulic oil is caused to be discharged from theoil pressure chamber 82 and hydraulic oil is fed to each retard oil pressure chamber. More specifically, by changing the operational state of the control valve (not shown), hydraulic oil is discharged from theoil pressure chamber 82, and thereby internal pressure in theoil pressure chamber 82 is reduced such that thestopper piston 80 is biased toward thefront plate 20 by the biasing force of thespring 81. Also, because hydraulic oil is fed to each retard oil pressure chamber in the above state, thevane rotor 50 is rotated in the retard direction, and thereby thestopper piston 80 is fitted into thefitting hole 23. - When the engine is commanded to stop in a state, where the
stopper piston 80 is located on the other side of the formation position in the retard direction, hydraulic oil is caused to be discharged from theoil pressure chamber 82, and hydraulic oil is fed to each advance oil pressure chamber. Due to the above configuration, thevane rotor 50 is rotated in the advance direction, and thereby thestopper piston 80 is fitted into thefitting hole 23. - The operation of the engine is usually stopped in the above normal state, where the
stopper piston 80 is fitted into thefitting hole 23, or in other words, where thevane rotor 50 is limited from being rotated relative to thehousing 11, and thereby the engine is set ready for the restart. - Next, the operation of the present embodiment in an unexpected state, where the engine is restarted after the unexpected stop of the engine, will be described. The operation may be stopped in a state, where the
stopper piston 80 is not fitted into thefitting hole 23, for example, when the engine is stopped unexpectedly. In the above case, if hydraulic oil remains in theoil pressure chamber 82 when the engine is restarted in the next operation, the remained hydraulic oil is caused to be discharged. Due to the above discharge, thestopper piston 80 is biased toward thefront plate 20 by the biasing force of thespring 81. Also, in the above case, variable torque is generated to thecamshaft 70. Due to the above, thevane rotor 50 fluctuates in the retard direction and in the advance direction. By the fluctuation of thevane rotor 50 in the retard direction and in the advance direction, thestopper piston 80, which is biased toward thefront plate 20, is fitted into thefitting hole 23. As a result, thevane rotor 50 is connected with thefront plate 20, and thereby the relative rotation of thevane rotor 50 relative to thefront plate 20, in other words, to thehousing 11 is limited. - In a conventional art, a limiting member is reciprocably displaceably received in an axial hole that includes a space defined by (a) an end portion of the limiting member opposite to the fitting hole and (b) the side wall of the housing. If the above space is closed in the conventional art, the followings may be expected. Specifically, when the limiting member is displaced in a direction for fitting with the fitting hole, a volume of the closed space is enlarged, and thereby pressure in the space is reduced. Thus, the above reduced pressure may restrict the limiting member from being displaced in the direction for fitting with the fitting hole. Also, when the limiting member is displaced in a direction for getting out of the fitting hole, the volume of the closed space is reduced, and thereby pressure in the space is increased. Thus, the limiting member may be restricted from being displaced in the direction for getting out of the fitting hole. As above, when the space is closed, the limiting member may be limited from being smoothly reciprocated.
- As described above, in the first embodiment of the present invention, because the
fitting hole 23 is exposed to atmosphere via theatmosphere communication hole 24, thefitting hole 23 does not store hydraulic oil. Thus, when thestopper piston 80 is brought into the fitted relation with thefitting hole 23, the fitting hole, which otherwise is required to push remained hydraulic oil toward the oil passage when the fitting hole were not exposed to atmosphere in the conventional art, is not required to push the remained hydraulic oil in thefitting hole 23. As a result, thestopper piston 80 is easily fitted into thefitting hole 23. As a result, responsivity of thestopper piston 80 is improved, and thereby the relative rotation of thevane rotor 50 relative to thehousing 11 is easily and highly accurately limited due to thestopper piston 80. As a result, responsivity of the valvetiming adjusting apparatus 10 is effectively improved, and thereby the phase of thecamshaft 70 is highly accurately controlled. - In the first embodiment of the present invention, even under the low-temperature situation, in which degree of viscosity of hydraulic oil is high, such as the time of starting the engine, responsivity of the
stopper piston 80 is made sufficiently high. Thus, even in the case of the restart of the engine after the unexpected stop, the relative rotation of thevane rotor 50 relative to thehousing 11 is easily limited by thestopper piston 80. - Also, in the first embodiment of the present invention, the
atmosphere communication hole 24 has the diameter w1 that is smaller than the diameter w2 of the end portion of thestopper piston 80, which end portion is fitted into thefitting hole 23. In other words, the diameter w1 of theatmosphere communication hole 24 is smaller than the diameter of thefitting hole 23. Due to the above configuration, theannular step surface 25 is formed between theatmosphere communication hole 24 and thefitting hole 23. When thestopper piston 80 is brought into the fitted relation with thefitting hole 23, thestopper piston 80 contacts thestep surface 25 such that thestopper piston 80 is limited from ejecting or jumping out of thehousing 11 through theatmosphere communication hole 24. Thus, even in a case, where theatmosphere communication hole 24 is formed in order to make thefitting hole 23 exposed to atmosphere, thestopper piston 80 is still limited from ejecting out through theatmosphere communication hole 24. - Furthermore, in the first embodiment of the present invention, the
chain sprocket 40 is provided with thepressure discharge hole 41 that is communicated with atmosphere. Thehole 55, in which thestopper piston 80 is reciprocably received, is communicated with atmosphere via thepressure discharge hole 41. Thus, even when thestopper piston 80 reciprocates in thehole 55, pressure in a space in thehole 55 defined between thestopper piston 80 and thechain sprocket 40 is kept similar to the atmospheric pressure. Due to the above configuration, thestopper piston 80 is smoothly reciprocably displaceable. Also, thehole 55 is communicated with atmosphere via theoblong groove portion 42 and thepressure discharge hole 41 regardless of the position of thevane 52 provided that thevane 52 is rotated relative to thehousing 11 within the predetermined angle range. Thus, thestopper piston 80 is capable of being smoothly reciprocably displaceable regardless of the position of thevane 52. Thus, responsivity of thestopper piston 80 is effectively improved, and thereby the relative rotation of thevane rotor 50 relative to thehousing 11 is easily and highly accurately limited by thestopper piston 80. - A valve timing adjusting apparatus according to the first modification of the present invention will be described with reference to
FIGS. 6 to 8 . It should be noted that similar components of the valve timing adjusting apparatus of the present modification, which are similar to the components of the valve timing adjusting apparatus of the first embodiment, will be indicated by the same numerals, and explanation thereof will be omitted. The first modification is different from the first embodiment in that theend surface 56 and theend surface 57 of thevane rotor 50 have a recess and a seal portion, and in that thechain sprocket 40 does not include theoblong groove portion 42. - As shown in
FIGS. 6 and 7 , thevane 52 has arecess 521 and aseal portion 522 on theend surface 56 that faces thefront plate 20 of thevane rotor 50. Therecess 521 is formed by arecess groove 523 on theend surface 56. Theseal portion 522 extends from thehub portion 51 along the outer edge of thevane 52 such that theseal portion 522 has a U shape, and theseal portion 522 is positioned to surround therecess 521 together with thehub portion 51. Also, theseal portion 522 is positioned around three ways or three sides of theseal members 15. Theseal portion 522 contacts thefront plate 20 such that theseal portion 522 is fluid tightly slidable on thefront plate 20. Due to the above configuration, leakage of hydraulic oil between the retardoil pressure chamber 301 and the advanceoil pressure chamber 311 is reduced. - Similar to the above, the
vane 53 has arecess 531 and aseal portion 532 on theend surface 56, and thevane 54 has arecess 541 and aseal portion 542. Theseal portions front plate 20 such that theseal portions front plate 20. Due to the above configuration, leakage of hydraulic oil between the retardoil pressure chamber 302 and the advanceoil pressure chamber 312, and leakage of hydraulic oil between the retardoil pressure chamber 303 and the advanceoil pressure chamber 313 are reduced. - As shown in
FIG. 8 , thevane 52 has arecess 524 and aseal portion 525 on theend surface 57 that faces thechain sprocket 40 of thevane rotor 50. Therecess 524 is formed by providing arecess groove 526 on theend surface 57. Theseal portion 525 extends from thehub portion 51 along the outer edge of thevane 52 to have a U shape, and theseal portion 525 is positioned to surround therecess 524 together with thehub portion 51. Also, theseal portion 525 is positioned around the three sides of theseal members 15. In other words, theseal portion 525 is shaped to face the three sides of theseal members 15. Theseal portion 525 contacts thechain sprocket 40 such that theseal portion 525 is fluid tightly slidable on thechain sprocket 40. Due to the above configuration, leakage of hydraulic oil between the retardoil pressure chamber 301 and the advanceoil pressure chamber 311 is reduced. - Similarly, the
vane 53 has arecess 534 and aseal portion 535 on the end surface 571 and thevane 54 has arecess 544 and aseal portion 545 on theend surface 57. Theseal portions chain sprocket 40 such that theseal portions chain sprocket 40. Due to the above configuration, leakage of hydraulic oil between the retardoil pressure chamber 302 and the advanceoil pressure chamber 312, and leakage of hydraulic oil between the retardoil pressure chamber 303 and the advanceoil pressure chamber 313 are reduced. - In the present modification, similar to the first embodiment, the
fitting hole 23 is communicated with atmosphere via theatmosphere communication hole 24. Also, although thechain sprocket 40 does not include the oblong groove portion differently from the first embodiment, thechain sprocket 40 include thepressure discharge hole 41 that extends through thechain sprocket 40 in the thickness direction of thechain sprocket 40 similar to the first embodiment. Because thevane 52 has therecess 524 on theend surface 57, thepressure discharge hole 41 is communicated with thehole 55 via therecess 524 even when thevane 52 is located at one of the full retard position and the full advance position. In other words, thehole 55 is communicated with atmosphere via therecess 524 and thepressure discharge hole 41 regardless of the position of thevane 52 when thevane 52 is rotated relative to thehousing 11 within the predetermined angle range defined between the full retard position and the full advance position. - The
fitting hole 23 and thepressure discharge hole 41 are formed at a position generally intermediate between the full retard position and the full advance position. The above full retard and advance positions correspond to the maximum displaceable positions that thevane 52 is displaceable to when thevane rotor 50 is rotated relative to thehousing 11. Thus, thefitting hole 23 and thepressure discharge hole 41 are always located a position correspondingly to the inward of the outer edge of thevane 52 when thevane 52 is located at any position between the full retard position and the full advance position. In other words, thefitting hole 23 and thepressure discharge hole 41 are always located to overlap with thevane 52 in the longitudinal direction when thevane 52 is located at any position between the full retard position and the full advance position, for example. - The
seal portion 522 of thevane 52 contacts thefront plate 20 such that theseal portion 522 is fluid tightly slidable on thefront plate 20. Thus, thefitting hole 23 is limited from being communicated with the retardoil pressure chamber 301 or the advanceoil pressure chamber 311, and thereby leakage of hydraulic oil from the retardoil pressure chamber 301 or from the advanceoil pressure chamber 311 to atmosphere via thefitting hole 23 and via theatmosphere communication hole 24 is reduced. Similarly, theseal portion 525 of thevane 52 contacts thechain sprocket 40 such that theseal portion 525 is fluid tightly slidable on thechain sprocket 40. Therefore, thepressure discharge hole 41 is limited from being communicated with the retardoil pressure chamber 301 or the advanceoil pressure chamber 311, and thereby leakage of hydraulic oil from the retardoil pressure chamber 301 or from the advanceoil pressure chamber 311 to atmosphere via thepressure discharge hole 41 is reduced. - As described above, in the first modification, the
vanes recesses recesses vanes front plate 20 through theseal portions vanes chain sprocket 40 through theseal portions vanes front plate 20 and thechain sprocket 40 through slidable surfaces having substantially small areas. Thus, even when hydraulic oil is present in a clearance between (a) thevane front plate 20 or in a clearance between (a) thevane chain sprocket 40, hydraulic oil may generate small resistance, and thereby thevane rotor 50 is easily rotated relative to thehousing 11. Specifically, although the degree of viscosity of hydraulic oil tends to be increased at the low-temperature situation, such as when the engine is started. However, in the first modification, even when hydraulic oil having high degree of viscosity is present in the clearance between (a) thevane front plate 20 or thechain sprocket 40, thevane rotor 50 is easily fluctuated and rotated relatively to thehousing 11. As a result, responsivity of thevane rotor 50 is effectively improved, and the phase of thecamshaft 70 is highly accurately controlled. - Also, in the first modification, the
fitting hole 23 is exposed to atmosphere via theatmosphere communication hole 24, and thehole 55 is exposed to atmosphere via thepressure discharge hole 41. Thus, similar to the first embodiment, responsivity of thestopper piston 80 is effectively improved. - A valve timing adjusting apparatus of the second modification of the present invention will be described with reference to
FIGS. 9 to 11 . It should be noted that similar components of valve timing adjusting apparatus of the present example, which are similar to the components of the valve timing adjusting apparatus of the first modification, will be indicated by the same numerals, and explanation thereof will be omitted. Recesses and seal portions of thevanes - As shown in
FIG. 10 , thevane 53 hasrecesses 631 and aseal portion 632 on theend surface 56. Theseal portion 632 radially outwardly extends from thehub portion 51 to have an I shape. Therecesses 631 are formed by providingrecess grooves 633 on both ends of theseal portion 632. Also, theseal portion 632 is positioned around the three sides of theseal members 15. Theseal portion 632 contacts thefront plate 20 such that theseal portion 632 is fluid tightly slidable on thefront plate 20. Due to the above configuration, leakage of hydraulic oil between the retardoil pressure chamber 302 and the advanceoil pressure chamber 312 is reduced. - Similarly, the
vane 54 hasrecesses 641 and aseal portion 642 on theend surface 56. Theseal portion 642 contacts thefront plate 20 such that theseal portion 642 is fluid tightly slidable on thefront plate 20. Due to the above configuration, leakage of hydraulic oil between the retardoil pressure chamber 303 and the advanceoil pressure chamber 313 is reduced. - As shown in
FIG. 11 thevane 53 hasrecesses 634 and aseal portion 635 on theend surface 57. Theseal portion 635 radially outwardly extends from thehub portion 51 to have an I shape. Therecesses 634 are formed by providingrecess grooves 636 on both ends of theseal portion 635. Also, theseal portion 635 is positioned around the three sides of theseal members 15. Theseal portion 635 contacts thechain sprocket 40 such that theseal portion 635 is fluid tightly slidable on thechain sprocket 40. Due to the above configuration, leakage of hydraulic oil between the retardoil pressure chamber 302 and the advanceoil pressure chamber 312 is reduced. - Similarly, the
vane 54 hasrecesses 644 and aseal portion 645 on theend surface 57. Theseal portion 645 contacts thechain sprocket 40 such that theseal portion 645 is fluid tightly slidable on thechain sprocket 40. Due to the above configuration, leakage of hydraulic oil between the retardoil pressure chamber 303 and the advanceoil pressure chamber 313 is reduced. - Explanation of the
recess 521, theseal portion 522, therecess 524, and theseal portion 525 shown inFIG. 9 ,FIG. 10 andFIG. 11 will be omitted because the configuration thereof are similar to those in the first modification. - As described above, also in the second modification, recesses are formed on both end surfaces of each vane along the rotation axis similar to the first modification. Thus, each vane slides on the internal wall surface of the
housing 11 through the seal portion provided to the vane. In other words, the vane slides on the internal wall surface of thehousing 11 through slidable surfaces having substantially small areas. In the case of the second modification, the areas of the slidable surfaces, through which the vane slides on the internal wall surface of thehousing 11, are smaller compared with those in the first modification. Thus, even when hydraulic oil is present in a clearance between the vane and the internal wall surface of thehousing 11, hydraulic oil generates substantially small resistance, and thereby thevane rotor 50 is easily rotated relative to thehousing 11. - In the above embodiment, the oblong groove portion, which is communicated with the pressure discharge hole, has a generally arc shape. In the other embodiment of the present invention, the oblong groove portion is not limited to having the arc shape. However, the oblong groove portion may have any shape. Also, the oblong groove portion may have any depth.
- Also, in the other embodiment of the present invention, each of the stopper piston and the fitting hole of the fitting ring may have a straight shape instead of the tapered shape.
- In the above embodiment or the modifications, the front plate is provided with the fitting ring, and the stopper piston is fitted into the fitting hole formed on the fitting ring. In the other embodiment of the present invention, a fitting ring may be provided on the chain sprocket located opposite to the front plate, and the stopper piston may be fitted to the chain sprocket. Similarly, the pressure discharge hole may be formed on the front plate instead of the chain sprocket.
- In the above embodiment or the modifications, the fitting ring is provided on the inner wall of the housing, and the stopper piston is fitted into the fitting hole formed on the fitting ring. In the other embodiment of the present invention, the fitting ring may not be formed on the inner wall of the housing. However, a fitting hole, which is communicated with atmosphere, may be formed on the housing such that the stopper piston is fitted into the above fitting hole.
- In the above embodiment or the modifications, the valve timing adjusting apparatus is applied to the intake valve of the engine. However, the valve timing adjusting apparatus of the present invention may be applicable to an exhaust valve.
- Additional advantages and modifications will readily occur to those skilled in the art. The invention in its broader terms is therefore not limited to the specific details, representative apparatus, and illustrative examples shown and described.
Claims (4)
1. A valve timing adjusting apparatus that is provided to a driving force transmission system for transmitting a driving force from a first shaft of an internal combustion engine to a second shaft that actuates at least one of an intake valve and an exhaust valve, wherein the valve timing adjusting apparatus adjusts opening and closing timing of the at least one of the intake valve and the exhaust valve, the valve timing adjusting apparatus comprising:
a housing that is rotatable about a rotation axis with one of the first shaft and the second shaft, wherein:
the housing includes a peripheral wall and side walls that are connected to both axial ends of the peripheral wall along the rotation axis; and
the housing defines a receiving chamber by the peripheral wall and the side walls;
a vane supporting portion that is received in the receiving chamber for being rotatable with the other one of the first shaft and the second shaft;
a vane member that is received in the receiving chamber, wherein:
the vane member is provided integrally with the vane supporting portion;
pressure of working fluid, which flows into and out of pressure chambers of the receiving chamber, causes the vane member to rotate relative to the housing within a predetermined angle range; and
the vane member includes an axial hole that extends therethrough along the rotation axis;
a limiting member that is reciprocably received in the axial hole for limiting the vane member from rotating relative to the housing;
a fitting hole that is provided to one of the side walls of the housing for fitting with one end of the limiting member; and
an atmosphere communication hole that is provided to the one of the side walls for communication with atmosphere, wherein:
the fitting hole is communicated with atmosphere via the atmosphere communication hole; and
the limiting member limits the vane member from rotating relative to the housing when the one end of the limiting member is fitted with the fitting hole.
2. The valve timing adjusting apparatus according to claim 1 , wherein:
the atmosphere communication hole has a diameter smaller than a diameter of the one end of the limiting member.
3. The valve timing adjusting apparatus according to claim 1 , further comprising:
a pressure discharge hole that is provided to the other one of the side walls of the housing for communication with atmosphere, wherein:
the axial hole is communicated with atmosphere via the pressure discharge hole regardless of a position of the vane member when the vane member is rotated relative to the housing within the predetermined angle range.
4. The valve timing adjusting apparatus according to claim 3 , further comprising.
a groove that is provided to the other one of the side walls to face the vane member, wherein:
the groove is communicated with the pressure discharge hole; and
the groove is located at a position that overlaps with the vane member along the rotation axis when the vane member is positioned within the predetermined angle range.
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
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JP2007-290656 | 2007-11-08 | ||
JP2007290656 | 2007-11-08 | ||
JP2008238613A JP2009133300A (en) | 2007-11-08 | 2008-09-17 | Valve timing adjusting apparatus |
JP2008-238613 | 2008-09-17 |
Publications (1)
Publication Number | Publication Date |
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US20090120392A1 true US20090120392A1 (en) | 2009-05-14 |
Family
ID=40622532
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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US12/264,347 Abandoned US20090120392A1 (en) | 2007-11-08 | 2008-11-04 | Valve timing adjusting apparatus |
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US (1) | US20090120392A1 (en) |
Cited By (4)
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EP2299071A1 (en) * | 2009-09-18 | 2011-03-23 | Schaeffler KG | Device for changing the phase of a camshaft relative to a crankshaft of a combustion engine |
US20120132165A1 (en) * | 2010-11-30 | 2012-05-31 | Delphi Technologies, Inc. | Method for operating a camshaft phaser |
US20120132164A1 (en) * | 2010-11-30 | 2012-05-31 | Delphi Technologies, Inc. | Method for operating an oil control valve |
US20120177520A1 (en) * | 2011-01-06 | 2012-07-12 | GM Global Technology Operations LLC | Reversible gerotor pump |
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US20020139332A1 (en) * | 2001-03-28 | 2002-10-03 | Akihiko Takenaka | Variable valve timing apparatus |
US20030121485A1 (en) * | 2001-11-21 | 2003-07-03 | Ina-Schaeffler Kg | Hydraulic camshaft adjuster and method for operating the same |
-
2008
- 2008-11-04 US US12/264,347 patent/US20090120392A1/en not_active Abandoned
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
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US20020139332A1 (en) * | 2001-03-28 | 2002-10-03 | Akihiko Takenaka | Variable valve timing apparatus |
US20030121485A1 (en) * | 2001-11-21 | 2003-07-03 | Ina-Schaeffler Kg | Hydraulic camshaft adjuster and method for operating the same |
Cited By (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP2299071A1 (en) * | 2009-09-18 | 2011-03-23 | Schaeffler KG | Device for changing the phase of a camshaft relative to a crankshaft of a combustion engine |
US20110067655A1 (en) * | 2009-09-18 | 2011-03-24 | Schaeffler Kg | Device for varying the angular position of a camshaft relative to a crankshaft of an internal combustion engine |
CN102022155A (en) * | 2009-09-18 | 2011-04-20 | 谢夫勒科技有限两合公司 | Device for changing relative angular position of camshaft relative to crankshaft of internal-combustion engine |
US8950369B2 (en) | 2009-09-18 | 2015-02-10 | Schaeffler Technologies Gmbh & Co. Kg | Device for varying the angular position of a camshaft relative to a crankshaft of an internal combustion engine |
US20120132165A1 (en) * | 2010-11-30 | 2012-05-31 | Delphi Technologies, Inc. | Method for operating a camshaft phaser |
US20120132164A1 (en) * | 2010-11-30 | 2012-05-31 | Delphi Technologies, Inc. | Method for operating an oil control valve |
US8464675B2 (en) * | 2010-11-30 | 2013-06-18 | Delphi Technologies, Inc. | Method for operating an oil control valve |
US8468989B2 (en) * | 2010-11-30 | 2013-06-25 | Delphi Technologies, Inc. | Method for operating a camshaft phaser |
US20120177520A1 (en) * | 2011-01-06 | 2012-07-12 | GM Global Technology Operations LLC | Reversible gerotor pump |
CN102588722A (en) * | 2011-01-06 | 2012-07-18 | 通用汽车环球科技运作有限责任公司 | Reversible gerotor pump |
US8734140B2 (en) * | 2011-01-06 | 2014-05-27 | Gm Global Technology Operations, Llc | Reversible gerotor pump |
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Owner name: DENSO CORPORATION, JAPAN Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:TAKAHASHI, HIROKI;SATO, OSAMU;REEL/FRAME:021780/0837 Effective date: 20081003 |
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