Patent Application
20130000578
The present disclosure relates in general to valve timing control apparatuses, and in particular to variable valve timing control apparatuses for internal combustion engines. The valve timing control apparatus controls a relative rotation between a camshaft and an output shaft, which can either be prevented or permitted by releasably locking a relative rotation of a rotor being driven by said camshaft with a rotational member, preferably a sprocket, a chain, a belt, a pulley being driven by said output shaft.
From the state of the art a cam phasing device as part of a variable valve timing control apparatus is well known that is applicable to internal combustion engines, such as described in U.S. Pat. No. 7,841,311 B. Especially with camshafts that include adjustable cams for intake and exhaust gas exchange valves of cylinders of a combustion engine on the same camshaft, a cam phaser device may be needed. Any kind of camshaft can be operated that has one or two different sets of cams, whereby the cams can be arranged on the same camshaft or on different camshafts. The device is applicable in an automotive environment as an automotive component.
A variable valve timing control apparatus of an internal combustion engine is a device that adapts the relative position of a gas exchange valve actuating component, such as a cam, with respect to a further shaft, such as a crankshaft. It is widely known to use camshafts for transmitting the actuating impulse. The impulse is applicable on at least one—normally several—gas exchange valves via a control shaft. The control shaft can have at least two concentrically arranged camshafts, or can have two separate camshafts arranged in parallel. The camshafts are adjustable in a rotatable manner with respect to a rotational member, e.g., a sprocket, a toothed belt, a pulley or a gear assembly, which is powered by the engine's rotational movement. The adjustment is achieved by adjusting a cam of the first camshaft in terms of its angle towards a cam of the second camshaft. To select the position, a cam phasing device is needed. The cam phasing device operates by rotatable vanes which are part of a rotor, provoking a swiveling relative movement between a driven member and an output member, which can be a rotor connected with a camshaft for opening and closing cylinder valves of the combustion engine.
The rotor's vanes can be profiled or can be flat, three-dimensional blocks extending out of the central rotor which can be referred to as rotor cores. The central rotor and the vanes are part of a vane adjuster. The cam phasing device can include at least two pivotable vane adjusters. Each pivotable vane adjuster is assigned to one of the two camshafts. In particular, a first vane adjuster is fixed to a first camshaft and a second vane adjuster is fixed to a second camshaft. The first vane adjuster operates the first camshaft whereas the second vane adjuster operates the second camshaft. The pivotable vane adjusters can be arranged axially one after the other in a direction of a valve control shaft. Both vane adjusters can be arranged on a common axis or can be arranged on parallel axes. The vane adjusters usually do not influence each other in their maximum swivel range. The first vane adjuster may still cover its full range while the second vane adjuster has picked any position between its maximum advanced and its maximum retarded position. With this design, the position of a first camshaft does not influence the selectability of a position for the second camshaft still occupying the same elongated space.
The variable valve timing control apparatus can further include rotor-type vane adjusters in that each pivotable vane adjuster is designed in a rotor-type manner. Each rotor-type vane adjuster can be changed in respect of its phase by hydraulic pressure in two sets of hydraulic chambers, which can provide a retard and an advance region of the valve timing control apparatus. The phase is measured in respect of a further shaft, such as the camshaft. The two sets of hydraulic chambers—retard and advance regions—form counter moving chambers to each other. The pivotable vane adjusters each constitute an output member of one of the camshafts. Each output member includes a vane rim. The vane rims are attached to rotor cores being movable between a first position and a second position limited by division bars of a surrounding stator housing. By using the design of vane-type cam phasers—which are known to a certain extent by themselves—a very fast and very responsive adjuster can be created.
In some cases, the variable valve timing control apparatus can include a double camshaft. The gas exchange valve control shaft is thereby a coaxially arranged double camshaft. The first camshaft can be formed of said double camshaft as a hollow body and the second camshaft is aligned in the hollow body and is placed in such a manner that through at least one recess a cam of the second camshaft pokes out to an outside of the first camshaft. The double camshaft is very efficient in terms of space. It occupies very little additional space outside of the camshaft as is necessary and advantageous in internal combustion engines.
Frequently, the variable valve timing control apparatus has only one drive pulley. The drive pulley is exposed to a driving means, such as a chain or a belt. Thus the cam phasing device has only one drive pulley, such as a sprocket, a toothed belt, a pulley, a gear box, etc., adapted to be driven by a chain which can surround a crankshaft of the internal combustion engine. The variable valve timing control apparatus has a side which is a near side of the camshaft, and the variable valve timing control apparatus has a side which is a far side from the camshaft. The variable valve timing control apparatus can be planar. The variable valve timing control apparatus has a communication collar on the near side. The near side bears conduits for intake and piping of a hydraulic fluid to each of the sets of chambers of the first and said second pivotable vane adjusters. The communication collar moves synchronously along with the drive pulley. The integration of hydraulic conduits for the first and second vane adjusters can contribute to the compactness of the variable valve timing control apparatus. The same applies to using only one drive pulley. The variable valve timing control apparatus has at least four conduits. Two of the four conduits are located in the vicinity of an axis of the camshaft which channel fluid from the communication collar to the pivotable vane adjuster. They conduct hydraulic fluid, such as engine oil, to the vane adjuster which is located farther away from the communication collar than the second pivotable vane adjuster. The two of the four conduits are located remotely from the axis of the camshaft channel from the communication collar to the second pivotable vane adjuster. The second vane adjuster is located closer to the communication collar. In a very dense circular cross-section, all conduits necessary for operation can be placed in the rotor core and the core of the variable valve timing control apparatus.
It is an object to further improve the above-described valve timing control apparatus.
According to an embodiment, a valve timing control apparatus for a combustion engine is proposed, including a rotational member, preferably a sprocket, a belt, a chain a pulley or any other device being driven by said combustion engine, and a rotor being mechanically coupled with a camshaft for controlling opening and closing of cylinder valves of said combustion engine. In a first configuration the rotor is locked to the rotational member, thus the rotor and the rotational member have a fixed phase while rotating. In a second configuration the rotor is unlocked from the rotational member, such that a switching phase of the valves in relation to the engine's rotational state can be controlled by an adjustable relative position between said rotational member and said rotor.
In other words, the valve timing control apparatus controls a relative rotation between a camshaft and an output shaft of the combustion engine, which can be either prevented or permitted. Said rotor is connected to said camshaft for switching input and output valves of one or multiple cylinders of said combustion engine. The rotor is releasably locked to a rotational member, e.g. a sprocket, toothed belt, pulley or gear box, connected to said output shaft of said combustion engine, to thereby prevent relative rotation between the camshaft and the output shaft by a locking pin. The locking pin is driven by a hydraulic system which controls said cam phasing adjustment. Thus, the locking pin blocks or enables a cam phasing adjustment between opening and closing of cylinder valves and a rotational state of the combustion engine.
In an embodiment the valve timing control apparatus includes a locking pin being axially aligned with said rotational member and said rotor, wherein said locking pin is hydraulically operated for locking said rotational member with said rotor in an intermediate position. An intermediate position can be any position between an advance- and retard-end-position defining a hydraulic advance chamber and a hydraulic retard chamber of equal (mid-position) or different volume. Thereby an intermediate position can be an arbitrary position between said end-positions and a mid-position and as a special case of an intermediate position a middle position is defined as a middle position between said end-positions. Said intermediate position can be a position near to a retard end position or a position near to an advance end position providing a larger phase shift capability in an advance or in a retard phase direction. Said locking pin engaging or releasing said rotor from said rotational member is driven by a hydraulic system for adjusting a cam phase between said rotational member and said rotor. The locking pin is aligned with an axis of the camshaft and the rotational member and the rotor, and is displaced via said axis by a certain distance. Engaging and releasing said locking pin is driven by a hydraulic system which operates with pressure of a fluid, wherein the locking pin is in an inactive state in a locked position by a force from a compression spring. The locking pin can be hydraulically operated, which means it can hydraulically released or engaged by applying pressure to a hydraulic system, wherein the hydraulic system can also provide relative adjustment of the rotor with respect to the rotational member by adjusting a relative position of the rotor to the rotational member in a positive or negative cam phase. Using a common hydraulic system for adjusting cam phase and releasing said locking pin enables the release of the locking pin simultaneously when pressurizing a hydraulic chamber for advancing or retarding valve timing of the cylinder valves. An intermediate position locking provides a fast adjustment in a negative or positive angle of the timing phase.
According to an embodiment said rotor includes a plurality of vanes and is rotatably embedded in a stator, preferably in a stator housing, including a plurality of division bars, such that in said intermediate position of said rotor with respect to said stator, a retard region and an advance region of equal or different volume are provided between lateral walls of said vane and said division bar. In an embodiment said rotational member is a sprocket. The retard region and the advance region are understood as hydraulic chambers, wherein pressurizing fluid in a retard region causes a cam shift in a negative phase while applying pressure to the chamber of the advance region causes a positive phase shift of the cam delay with respect to the rotational state of the combustion engine. In said intermediate position, both regions can have an equal or a different volume such that the rotor can be adjusted in a negative or positive angle in an equal amount with respect to the rotational member. The stator includes a stator housing and a rotational member, such as a sprocket, a pulley or a gear. The retard region and the advance region are defined by lateral walls of said vane of said rotor and by lateral walls of said division bars of said stator housing. It is conceivable that only one vane and only two neighboring division bars define the hydraulic system of the valve timing control apparatus, but also a plurality of vanes and a plurality of division bars can define a plurality of retard and advance regions such that the hydraulic system operates a plurality of pressure chambers.
According to an embodiment said locking pin includes a compression spring for forcing said locking pin in a pressureless hydraulic state in a locking position in a recess in said stator, preferably in said sprocket, pulley or gear. Since a stator includes a stator housing and a rotational member as a sprocket, pulley or gear, it is also conceivable, that said locking pin can be forced in a locking position in a recess of said stator housing. Said locking pin can be provided as a bushing-type or pot-type cylindrical pin, wherein in the inner hole of the pin a compression spring can be supported for defining a locked position in a pressureless state.
The locking hole chamber can be vented to the atmosphere by a vent passage, such as a front vent passage depicted in the figures. In a further embodiment said locking pin includes a locking hole chamber in the recess of the stator (a recess in said stator housing or a recess in said rotational member such as sprocket, pulley or gear) and a locking ring chamber in an annular channel between locking pin and vane. If the rotor includes only a small amount of vanes, e.g. three vanes or less, the width of each vane can be designed so broad, that a locking hole recess is covered even in an end position of said rotor with respect to said stator. In such a case, locking hole chamber and locking ring chamber can be hydraulically decoupled. A vent hole towards atmospheric pressure or towards the main oil gallery of the engine can be provided in the locking hole recess and the locking pin can be activated by pressurizing the locking ring chamber. Preferably both channels are in fluid communication with each other via a connection passage for engaging or releasing the locking pin for providing a two step locking pin. Providing a two step locking pin, whereby locking hole chamber and locking ring chamber are fluidly connected by a connecting passage is advantageous in a rotor design with a rather large number of vanes, e.g. four vanes or more, whereby the width of each vane is rather thin. Thus when rotatably moving said rotor against said stator in an end position, the locking hole of the stator (being located either in the stator housing or in the rotational member as said sprocket) can be set free and hydraulic fluid could flow out of the advance region (advance chamber) or said retard region (retard chamber) into the main oil gallery of the engine. In this case connecting locking hole chamber with locking ring chamber and hydraulically decoupling locking hole chamber from the main oil gallery prevents a loss of hydraulic fluid from either retard or advance region in an end position of the stator. The axial end of the locking pin and the recess of the sprocket can define a locking hole chamber and the enlarged diameter of the locking pin together with a section of the outer peripheral region of said pin-cylinder and its guiding hole in the rotor can provide a locking ring chamber, wherein both chambers, locking ring chamber and locking hole chamber, can be connected via a connection passage with a flow resistance R2 being sufficiently low such that fluid can force the locking pin from an engaged to a released position by introducing pressure into the locking hole chamber and/or in the locking ring chamber.
According to an embodiment said hydraulic system includes a pump, a proportional oil control valve being in fluid communication with said pump via a pressure passage, said retard region and said advance region being in fluid communication with said oil control valve by an advance passage and a retard passage. Said locking pin can be in fluid communication either with said pump, with said oil control valve or with said retard region and said advance region. An on/off control valve can be in fluid communication with said locking pin via a release passage for switching said locking pin between a locked position and a released position, wherein said on/off control valve is in fluid communication with an oil reservoir via an oil return passage. The pump provides hydraulic pressure for operating the hydraulic system for cam phasing a camshaft with respect to an output shaft of the combustion engine. An oil control valve, which can be a 4/3 or 4/4 valve, controls locking, positive or negative, cam phasing or depressurizing of the hydraulic system of the valve timing control apparatus. On the input side of the oil control valve a pressure passage and a connection passage to an oil reservoir can be connected. On the output side of the oil control valve an advance passage and a retard passage for pressurizing an advance region and a retard region of said rotor can be connected. The hydraulic system for releasing or engaging the locking pin can be connected to the pressure passage of said pump or to both the advance and retard passage for pressurizing the advance or retard region of said rotor. Thus, in a first case, the locking pin can be engaged or released independently from applying pressure to an advance region or a retard region of the rotor, while in the second case, the locking pin can be driven while pressurizing the advance or the retard region for providing a positive or negative cam phasing. Preferably said on/off control valve and said oil control valve are provided as separate valve units. Providing two functionally and structurally separate valve units, a proportional valve unit, preferably a 4/3- or 4/4-valve as oil control valve and a 2/2 binary switching or also proportional on/off control valve provide a cheaper and more robust valve timing control apparatus as an integrated design of both valve functionalities—proportional oil control and on/off switching functionality in a single valve unit. Such a combined design is rather expensive and increases malfunction of the valve timing control apparatus.
According to an embodiment at least lateral walls of said vane include an A-port passage and a B-port passage between said retard and advance region and said locking pin. Said locking pin can be in fluid communication with said on/off control valve via a release passage, wherein each A/B-port passage includes a check valve preventing an exchange of hydraulic fluid between said retard and advance region side or at least an orifice with a flow resistance R1, such that said locking pin is hydraulically coupled with said retard and advance region via said A-port and B-port passage and hydraulic fluid is flowable in a very small amount between said retard/advance region through said locking pin towards said on/off control valve. In other words, the hydraulic system is directly connected via said A-port and B-port of a lateral wall through the retard and advance region of said rotor with said locking pin, such that when pressurizing the advance or the retard region, hydraulic fluid can enter the respective port for releasing said locking pin such that a cam phasing can be adjusted. For preventing an exchange of hydraulic fluid between said advance region and retard region, check valves or orifices can limit the amount of flow or can prevent a fluid exchange. Said check valves or orifices can be provided in said A-port and said B-port, which allow a sufficient flow of hydraulic fluid for enabling releasing of said locking pin but preventing flow of hydraulic fluid from one region to another region. Regularly said oil pump comprises another check valve preventing a backflow of hydraulic fluid from the hydraulic system backwards through the pump into said oil reservoir.
According to an embodiment at least lateral walls of a vane include an A-port passage and a B-port passage between said retard and advance regions and said locking pin, and said locking pin is in fluid communication with said on/off control valve via two separate release passages, wherein both A-port and B-port passages are hydraulically decoupled from each other and coupled with separate release passages via said locking pin such that said locking pin is hydraulically separately coupled with said retard and advance region by said A-port and B-port passages. Hydraulic fluid flows separately between said retard/advance regions through said locking pin through separate release passages towards said on/off control valve. Preferably said assembly of locking pin, rotor vane and stator provide a locking hole chamber and a locking ring chamber being hydraulically decoupled from each other, whereby said A-Port passage is connected with said locking hole chamber and said B-port passage is connected with said locking ring chamber. Thus said locking pin is provided as two step locking pin. The on/off control valve provides the possibility of separately switching said locking pin, which enables a pre-pressurizing of said advance or retard region, and by opening said on/off control valve a locking pin is released or engaged for a fast phase switching of the valve control timing control apparatus. In this embodiment, two separate fluid systems connect the advance region with the locking pin and the on/off check valve and said retard region with said locking pin and said on/off control valve. Liquid fluid from the advance and the retard region does not mix, such that an orifice or check valves are not needed for preventing exchange of hydraulic fluid between said retard and said advance region. The before mentioned two step locking pin concept with a complete separation of A-port and B-port passages or A- and B-locking pin supply passages for independently pressurizing locking hole chamber and locking ring chamber in an hydraulically decoupled way can easily be employed to each of the different embodiments of the invention, preferably to embodiments depicted in
According to an embodiment said locking pin is in fluid communication with said on/off control valve by a locking pin activation passage and by said release passage, said locking pin activation passage and said release passage being in fluid communication with a locking pin supply passage, the locking pin supply passage is either in fluid communication with said advance passage and said retard passage via an A-locking pin supply passage and a B-locking pin supply passage, connecting said retard region and said advance region with said oil control valve, or said locking pin supply passage is in fluid communication with said pressure passage connecting said pump with said oil control valve, such that said retard/advance region are hydraulically decoupled from said locking pin. According to this embodiment, the hydraulic system for locking and releasing said locking pin is separated from the hydraulic advance and retard region chambers. The locking pin supply passage for supplying hydraulic pressure for releasing said locking pin is either connected to said pressure passage connecting said pump with said oil control valve or is connected to said advance passage and/or retard passage such that hydraulic pressure is supplied if the advance and/or the retard passage are pressurized for adjusting the cam phase. Connecting the hydraulic sub-system for releasing said locking pin with said pressure passage enables locking and releasing said locking pin independently from adjusting said cam phase. Connecting the hydraulic sub-system for releasing said locking pin with said A- and said B-locking pin supply passage enables locking and releasing said locking pin depending on an adjustment of said cam phase. The A-locking pin supply passage and the B-locking pin supply passage connect said advance passage and said retard passage with said locking pin supply passage. The locking pin is driven by the locking pin activation passage, which can also be labeled as locking pin vent oil passage, which when pressurized, releases said locking pin and which, when in a depressurized state, locks said locking pin, advantageously with the help of a compression spring. Thus, hydraulic fluid does not flow from the advance and retard region directly to said locking pin but bypasses the advance and retard chamber for enabling locking or releasing of said locking pin. Therefore a mixing of fluid from advance and retard region is prevented. In a locking position the pressure from the pump is not cut off by a blocked center valve position but for instance due to the fact that the engine is off and consequently the oil pump is also off.
According to an embodiment said locking pin supply passage includes an orifice having a flow resistance R3 and/or said A-port passage/A-locking pin passage and B-port passage/B-locking pin passage include an orifice having a flow resistance R1 being much larger than the flow resistance R3, such that R3 is much smaller than R1 (R1>>R3). In other words, said locking pin supply passage can have a big diameter and a short length such that the hydraulic fluid can flow without resistance through said locking pin supply passage making R3 almost zero. In contrast thereto, said A-locking pin supply passage/A-port passage and B-locking pin supply passage/B-port passage connecting said locking supply passage with said oil control valve or with the pressure passage have a rather large flow resistance such that only a small amount of hydraulic fluid flows for releasing said locking pin, whereby said A-locking pin supply passage/A-port passage and B-locking pin supply passage/B-port passage connect said advance and retard passage, such that only a small amount of hydraulic fluid can flow from said advance passage to said retard passage through said comparatively high flow resistance R1.
According to an embodiment said A-locking pin supply passage and said B-locking pin supply passage and/or said locking pin supply passage include a check valve preventing an exchange of hydraulic fluid between said retard and advance passage regions. Said check valve can be included in said A-locking pin supply passage and/or said B-locking pin supply passage and can also be included in said locking pin supply passage. The check valve prevents mixing of hydraulic fluid of said advance and retard passage.
According to an embodiment said on/off control valve is arranged centrally in a hub of said rotor, such that said locking pin supply passage can be provided with a flow resistance R3 of practically zero. This embodiment suggests to arrange said on/off control valve inside said rotor in a central position such that said valve can rotate with said rotor and can provide a locking pin supply passage with at least a very small flow resistance, such that the locking pin supply passage is practically not existent and can be designed with a very short length and with a large diameter.
According to an embodiment the check valve can be a shuttle valve, including two input and one output port. The shuttle valve does not prevent a unidirectional flow from one port to another port but prevents flow from one input port to another input port, but allows flow from either input ports to the output. Thus, the two check valves can be designed as a shuttle valve for preventing exchange of hydraulic fluid between said advance and retard region.
According to another aspect a method for adjusting a valve timing of a combustion engine according to one of the foregoing embodiments is proposed. Said method includes the steps of providing pressurized hydraulic fluid in a hydraulic system at an input port of an oil control valve; bringing said oil control valve in an advance phase or retard phase position whereby hydraulic fluid in said advance or retard passage is pressurized; and switching between said first configuration in which said rotor is in a locked position with said stator including said rotational member and in said second configuration in which said rotor is released from said stator including said rotational member. In other words the method proposes to bring said oil control valve in a valve position for adjusting said relative rotational position between said rotor and said stator to a defined position and to switch between a locking position (first configuration) and a release position (second configuration) of rotor with respect to said stator. In various embodiments said switching depends on a combination of valve positions of said oil control valve and said on/off control valve, or solely depends on a valve position of said on/off control valve. Pressure from the oil pump is provided as long as said engine is running.
According to an embodiment of the operating method said first configuration is a locked position of said locking pin, locking said rotor with said stator including said rotational member in an intermediate position, and said second configuration is a released position of said locking pin releasing said rotor from said stator such that said rotor's rotational position with respect to said stator can freely be adjusted between an advance end position and a retard end position. The advance and retard end positions are defined as positions of maximal advance phase angle or maximal retard phase angle of said rotor with respect to said stator, structurally it can be seen as a position of the rotor, in which a lateral side wall of a rotor is in close contact with a lateral wall of a stator housing division bar, whereby a hydraulic volume of said advance or retard region (chamber) is minimized.
According to an embodiment of the operating method releasing and locking said locking pin is operated by a locking-pin hydraulic system including an on/off valve being functionally and structurally separate form said oil control valve and being provided for switching between said first and said second configuration, whereby said locking-pin hydraulic system is at least partly decoupled from said hydraulic system for pressurizing said advance and retard region. Said locking pin hydraulic system can decouple hydraulic fluid being pressurized in said advance and retard chamber defined by rotor and stator assembly from hydraulic fluid within said locking pin locking chamber (locking hole chamber and/or locking ring chamber), such that hydraulic fluid of said advance/retard region can be pressurized independently from hydraulic fluid for operating said locking pin. A vane of said rotor including said locking pin can be manufactured without additional bores or check valves reducing production costs, and a risk of fluid leakage between advance and retard region through bores of said vane is minimized.
It is understood that variations may be made in the foregoing without departing from the scope of the disclosure. For example, one or more of the above-described exemplary embodiments may include one or more of the elements and teachings of the embodiments disclosed in U.S. Pat. No. 7,841,311, the entire disclosure of which is incorporated herein by reference.
a is a sectional view of a portion of the valve timing control apparatus of
b is a perspective view of a portion of the valve timing control apparatus of
c is a perspective sectional view of a portion of the valve timing control apparatus of
d is a perspective view of a portion of the valve timing control apparatus of
a is a diagrammatic illustration of a valve timing control apparatus, according to an exemplary embodiment;
b and 3c are diagrammatic illustrations of respective portions of the valve timing control apparatus of
a is a sectional view of a valve timing control apparatus, according to an exemplary embodiment;
b is a partial sectional/partial diagrammatic view of a portion of the valve timing control apparatus of
a and 5b are sectional views of respective portions of the valve timing control apparatus of
a and 6b are perspective views of respective portions of the valve timing control apparatus of
a and 10b are cross- and length-sectional views, respectively, of a valve timing control apparatus, according to a further embodiment;
a and 11b are diagrammatic illustrations of a hydraulic system for controlling the apparatus of
a and 12b are cross- and length-sectional views, respectively, of a valve timing control apparatus, according to a further embodiment;
a and 13b are diagrammatic illustrations of an embodiment of a hydraulic system for controlling the apparatus of
a and 14b are diagrammatic illustrations of another embodiment of a hydraulic system for controlling the apparatus of
a and 15b are diagrammatic illustrations of yet another embodiment of a hydraulic system for controlling the apparatus of
a, 18b, 18c and 18d are comparative diagrammatic illustrations of different embodiments of a valve timing control apparatus.
In an exemplary embodiment, as illustrated in
In an exemplary embodiment, as illustrated in
The locking pin 16 includes an enlarged-diameter portion 98 at one end, and an axially extending opening 96 formed in the enlarged-diameter portion 98. The axially extending opening 96 receives a compression spring 60. A clip 76 is disposed axially between the cover 56 and the enlarged-diameter portion 98 of the locking pin 16. One end of the compression spring 60 engages the clip 76 and the other end of the compression spring 60 engages an inner surface 94 of the locking pin 16 that is defined by the opening 96. A check ring 58 is disposed within the bore 18 and at least partially extends about the locking pin 16. The thin check ring 58 acts as band-shaped check valve spring which can seal the A-port and B-port passage 26,28 in a backflow direction such that fluid can enter into the locking pin hydraulic chambers but can not flow back into the A-port- and B-port passages 26, 28, as described in U.S. Pat. No. 7,600,531 B thus hydraulically decoupling retard and advance region 70, 72, In an exemplary embodiment, each of the check valves 24a, 24b illustrated in
The sprocket 50 includes a recess 64 formed in a face thereof, and a radial slot 66 extending radially outwardly from the recess 64. The sprocket 50 is operably coupled to an output shaft or crankshaft 42 of an internal combustion engine. The sprocket 50 is operably coupled to the crankshaft 42 so that rotation of the crankshaft 42 causes the sprocket 50 to rotate.
The bore 18 is in fluid communication with the on/off control valve 20 via a release fluid passage 32. The release fluid passage 32 includes a circumferentially extending locking control groove 86 formed in the outer surface of the camshaft 42, an axially extending passage formed in the camshaft 42, an axially extending passage formed in the rotor 40, and a radially extending passage 68 formed in the rotor 40.
Each advance region 72 is in fluid communication with the oil control valve 14 via an advance fluid passage 34. Each advance fluid passage 34 includes a common circumferentially extending advance groove 78 formed in the camshaft 42, a common axially extending passage formed in the camshaft 42, and a respective one of a plurality of radially extending passages 68 formed in the center portion 44 of the rotor 40. The advance region 72 adjacent to the vane 30 through which the bore 18 is formed is in fluid communication with the bore 18 via the A-port 26 and the check valve 24a proximate to the A-port 26.
Each retard region 70 is in fluid communication with the oil control valve 14 via a retard fluid passage 36. Each retard fluid passage 36 includes a common circumferentially extending retard groove 80 formed in the camshaft 42, a common axially extending passage formed in the camshaft 42, and a respective one of a plurality of radially extending passages 68 formed in the center portion 44 of the rotor 40. The retard region 70 adjacent to the vane 30 through which the bore 18 is formed is in fluid communication with the bore 18 via the B-port 28 and the check valve 24b proximate to the B-port 28.
In operation, in an exemplary embodiment, the apparatus 10 illustrated in
During operation, in an exemplary embodiment, the rotor 40 is releasably locked to the sprocket 50, thereby preventing relative rotation between the sprocket 50 and the rotor 40. More particularly, the locking pin 16 extends into the recess 64 formed in the sprocket 50, thereby preventing relative rotation between the sprocket 50 and the rotor 40. In this configuration, the bore 18 is axially aligned with the recess 64, and the axial slot 46 formed in the vane 30 in which the bore 18 is formed is axially aligned with the distal end of the radial slot 66 extending from the recess 64. The spring 60 applies a biasing force against the locking pin 16, urging the locking pin 16 to extend from the bore 18 into the recess 64 formed in the sprocket 50, thereby locking the rotor 40 to the sprocket 50. This activated or locked position of the locking pin 16 is illustrated in
During operation, in an exemplary embodiment, the rotor 40 is unlocked from the sprocket 50, thereby permitting relative rotation between the sprocket 50 and the rotor 40. More particularly, the oil control valve 14 supplies fluid, such as oil, to the respective advance regions 72 and/or the respective retard regions 70. In an exemplary embodiment, the oil control valve 14 supplies oil to the respective advance regions 72 via the advance fluid passage 34. In an exemplary embodiment, the oil control valve 14 supplies oil to the respective retard regions 70 via the retard fluid passage 36. As a result, in an exemplary embodiment, oil flows from the advance region 72 adjacent to the vane 30 through which the bore 18 is formed, through the port A 26 and the check valve 24a proximate thereto (i.e. the check ring 58), into the bore 18. In an exemplary embodiment, in addition to, or instead of, flowing from the advance region 72, oil flows from the retard region 70 adjacent to the vane 30 through which the bore 18 is formed, through the B-port 28 and the check valve 24b proximate thereto (i.e., the check ring 58), into the bore 18. The on/off control valve 20 is closed. Since the on/off control valve 20 is closed, fluid in the bore 18, recess 64, radial slot 66, axial slot 46, etc. is not vented out via the release fluid passage 32. As a result, as more oil is supplied into the bore 18 via the A-port and/or B-port, the hydraulic pressure in the bore 18 increases. When the oil pressure in the bore 18 becomes greater than the urging or biasing force of the spring 60, the spring 60 is compressed or further compressed by the locking pin 16, and the locking pin 16 moves out of the recess 64 formed in the sprocket 50, but continues to extend within the bore 18. As a result of this released position, the rotor 40 is unlocked from the sprocket 50. In an exemplary embodiment, the locking pin 16 moves out of or is otherwise released from the recess 64 formed in the sprocket 50 and thus the rotor 40 is unlocked from the sprocket 50 when, for example, the internal combustion engine is in a steady state or in normal operation (i.e., not stopping or starting), and/or at any time the hydraulic pressure in the bore 18 is greater than the urging or biasing force of the spring 60.
During operation, in an exemplary embodiment, the rotor 40 is again releasably locked to the sprocket 50. More particularly, when the locking pin 16 is moved out of or otherwise released from the recess 64 formed in the sprocket 50 and thus the rotor 40 is unlocked from the sprocket 50, the hydraulic pressure in the bore 18 is decreased by opening the on/off control valve 20. Additionally, in several exemplary embodiments, the pressure supplied by the oil control valve 14 is decreased, thereby decreasing the hydraulic pressure in the bore 18. In response to the opening of the on/off control valve 20, oil in the bore 18, the recess 64 formed in the sprocket 50, the radial slot 66 formed in the sprocket 50, the axial slot 46 formed in the vane 30, and the radial passage 68 formed in the rotor 40, vents out to the oil reservoir 22 via at least the release fluid passage 32 and the on/off control valve 20.
When the urging or biasing force applied to the locking pin 16 by the spring 60 is greater than the hydraulic pressure in the bore 18, the spring 60 urges the locking pin 16 back into the recess 64, thereby releasably locking the rotor 40 to the sprocket 50. Since the on/off control valve 20 is open, any fluid in the bore 18, recess 64, radial slot 66, axial slot 46, radial passage 68, etc. is vented out via the release fluid passage 32 and the on/off control valve 20.
During the above-described operation, in an exemplary embodiment, the on/off control valve 20 of the apparatus 10 illustrated in
In an exemplary embodiment, as illustrated in
In an exemplary embodiment, as illustrated in
In an exemplary embodiment, the housing 54 includes a circumferentially extending portion that extends about the rotor 40, and a plurality of protrusions extending radially inwardly from an inside surface of the circumferentially extending portion. Each vane 30 extends between two protrusions of the housing 54, thereby defining an advance region 72 between the vane 30 and one of the two protrusions, and a retard region 70 between the vane 30 and the other of the two protrusions. A cover 56 is coupled to the housing 54 so that each of the housing 54 and the rotor 40 is axially disposed between the sprocket 50 and the cover 56.
Each of the advance regions 72 is in fluid communication with a proportional oil control valve 14 via an advance fluid passage 34. Each advance fluid passage 34 includes a common circumferentially extending advance groove 78 formed in an outer surface of the camshaft 42, a common axially extending advance passage 34 formed in the camshaft 42, and a respective one of a plurality of radially extending passages 68 formed in the center portion 44 of the rotor 40.
Each of the retard regions 70 is in fluid communication with the oil control valve 14 via a retard fluid passage 36. Each retard fluid passage 36 includes a common circumferentially extending retard groove 80 formed in an outer surface of the camshaft 42, a common axially extending retard passage 36 formed in the camshaft 42, and a respective one of a plurality of radially extending passages 68 formed in the center portion 44 of the rotor 40.
An axially extending locking pin 16 extends within the bore 18, and includes an enlarged-diameter portion 98 at one end, an annular channel 92 formed in the outside surface of the locking pin 16 and positioned adjacent to the enlarged-diameter portion 98, and an axially extending opening 96 formed in the enlarged-diameter portion 98. The axially extending opening 96 receives a compression spring 60. A clip 76 is disposed axially between the cover 56 and the enlarged-diameter portion 98 of the locking pin 16. One end of the compression spring 60 engages the clip 76 and the other end of the compression spring 60 engages an inner surface 94 of the locking pin 16 that is defined by the opening 96. The sprocket 50 includes a recess 64 formed in a face thereof, and a radial slot 66 extending radially outwardly from the recess 64.
The bore 18 is in fluid communication with an on/off control valve 20 via a locking control passage 32. The locking control passage 32 includes a circumferentially extending locking control groove 86 formed in an outer surface of the camshaft 42, an axially extending passage formed in the camshaft 42, an axially extending passage formed in the rotor 40, and a radially extending angular passage 68 formed in the rotor 40.
A pump 12 is in fluid communication with the proportional oil control valve 14 by an oil pressure passage 100. The pump 12 pressurizes hydraulic fluid for operating the hydraulic advance/retard cam phaser system and the hydraulic locking pin system. A release passage 32 is in fluid communication with the on/off control valve 20 for venting hydraulic fluid from the hydraulic locking pin system. A reservoir 22, such as an oil reservoir, is in fluid communication with each of the oil control valve 14 and the on/off control valve 20 via an oil return passage 74. Depending on a switching position of said oil control valve 12, the rotor 40 moves in an advance or retard position with respect to said stator. Depending on a switching position of said on/off-valve 20 and in some embodiments also of said oil control valve 12, said locking pin 16 is in a locking or an unlocking position.
In operation, in an exemplary embodiment, the apparatus 10 illustrated in
During operation, in an exemplary embodiment, the rotor 40 is releasably locked to the sprocket 50, thereby preventing relative rotation between the sprocket 50 and the rotor 40. More particularly, the locking pin 16 extends into the recess 64 formed in the sprocket 50, thereby preventing relative rotation between the sprocket 50 and the rotor 40. In this configuration, the bore 18 is axially aligned with the recess 64, and the axial slot 46 formed in the vane 30 in which the bore 18 is formed is axially aligned with the distal end of the radial slot 66 extending from the recess 64. The spring 60 applies a biasing force against the locking pin 16, urging the locking pin 16 to extend from the bore 18 into the recess 64 formed in the sprocket 50, thereby locking the rotor 40 to the sprocket 50. This activated or locked position of the locking pin 16 is illustrated in
Thus, fluid in the recess 64 and/or the radial slot 66 of the sprocket 50 is vented out separately from the fluid that is vented out from the bore 18 (via the locking control passage 32). Axial slot 46, radial slot 66, and radial slot in vane 84 provide a connection passage 102 between locking ring chamber 108 and locking hole chamber 106 depicted in
During operation, in an exemplary embodiment, the rotor 40 is unlocked from the sprocket 50, thereby permitting relative rotation between the sprocket 50 and the rotor 40. More particularly, the on/off control valve 20 supplies fluid, such as oil, to the bore 18 via the locking control passage 32. At least a portion of this fluid is disposed in the annular channel 92 of the locking pin 16. As a result, as more oil is supplied to the bore 18 via the locking control passage 32, the hydraulic pressure in the bore 18 increases. When the oil pressure in the bore 18 becomes greater than the urging or biasing force of the spring 60, the spring 60 is compressed or further compressed by the locking pin 16, and the locking pin 16 moves out of the recess 64 formed in the sprocket 50, but continues to extend within the bore 18. As a result of this released position, the rotor 40 is unlocked from the sprocket 50. In an exemplary embodiment, the locking pin 16 moves out of or is otherwise released from the recess 64 formed in the sprocket 50 and thus the rotor 40 is unlocked from the sprocket 50 when, for example, the internal combustion engine is in a steady state or in normal operation (i.e., not stopping or starting), and/or at any time the hydraulic pressure in the bore 18 is greater than the urging or biasing force of the spring 60. In several exemplary embodiments, the hydraulic pressure supplied to the bore 18 by the on/off control valve 20 is different than the hydraulic pressure supplied to the advance regions 72 and/or retard regions 70 by the proportional oil control valve 14.
In an exemplary embodiment, when the rotor 40 is unlocked from the sprocket 50 due to the hydraulic pressure supplied by the on/off control valve 20, oil in the bore 18 and/or the annular channel 92 is not permitted to vent or otherwise drain via the front vent passage 82 because (a) the enlarged-diameter portion 98 of the locking pin 16 and/or the clip 76 prevents the oil disposed in the bore 18 and/or the annular channel 92 on the right hand side of the enlarged-diameter portion 98 (as viewed in
During operation, in an exemplary embodiment, the rotor 40 is again releasably locked to the sprocket 50. More particularly, when the locking pin 16 is moved out of or otherwise released from the recess 64 formed in the sprocket 50 and thus the rotor 40 is unlocked from the sprocket 50, the pressure supplied by the on/off control valve 20 is decreased, thereby rapidly decreasing the hydraulic pressure in the bore 18. In response, oil in the bore 18 and/or the annular channel 92 vents out to the oil reservoir 22 via at least the locking control passage 32 and the on/off control valve 20. And oil in the recess 64, the radial slot 66 formed in the sprocket 50, the axial slot 46 formed in the vane 30, and the radial slot 84 formed in the vane 30, vents out via at least the notch 90 of the front vent passage 82, separately from the venting of the oil in the bore 18 and/or the annular channel 92. When the urging or biasing force applied to the locking pin 16 by the spring 60 is greater than the hydraulic pressure in the bore 18, the spring 60 urges the locking pin 16 back into the recess 64, thereby releasably locking the rotor 40 to the sprocket 50.
During the above-described operation, in an exemplary embodiment, the on/off control valve 20 of the apparatus 10 illustrated in
In an exemplary embodiment,
In an exemplary embodiment, as illustrated in
a depicts a cross-sectional view of a cam phaser 52 including a rotor 40 and a stator with a stator housing 54. Furthermore,
a and 11b show a block-diagram of a hydraulic system for controlling of a locking pin 16 of the embodiment of a valve timing control apparatus 10 displayed in
In
a shows a cross-sectional view, and
a and 13b show similar schematic illustrations as
b shows a schematic illustration of the layout of
a and 14b show in similar schematic views as
a and 15b show another hydraulic system configuration of a valve timing control apparatus according to an embodiment. The overall layout is similar to the layouts depicted in
Finally,
In
In several exemplary embodiments, the elements and teachings of the various illustrative exemplary embodiments may be combined in whole or in part in some or all of the illustrative exemplary embodiments. In addition, one or more of the elements and teachings of the various illustrative exemplary embodiments may be omitted, at least in part, or combined, at least in part, with one or more of the other elements and teachings of the various illustrative embodiments.
In several exemplary embodiments, while different steps, processes, and procedures are described as appearing as distinct acts, one or more of the steps, one or more of the processes, or one or more of the procedures may also be performed in different orders, simultaneously or sequentially. In several exemplary embodiments, the steps, processes or procedures may be merged into one or more steps, processes or procedures. In several exemplary embodiments, one or more of the operational steps in each embodiment may be omitted. Moreover, in some instances, some features of the present disclosure may be employed without a corresponding use of the other features. Moreover, one or more of the above-described embodiments or variations may be combined in whole or in part with any one or more of the other above-described embodiments or variations.
Any spatial references such as, for example, “upper,” “lower,” “above,” “below,” “between,” “bottom,” “vertical,” “horizontal,” “angular,” “upwards,” “downwards,” “side-to-side,” “left-to-right,” “left,” “right,” “right-to-left,” “top-to-bottom,” “bottom-to-top,” “top,” “bottom,” “bottom-up,” “top-down,” etc., are for the purpose of illustration only and do not limit the specific orientation or location of the structure described above.
Although several exemplary embodiments have been described in detail above, the embodiments described are exemplary only and are not limiting, and those skilled in the art will readily appreciate that many other modifications, changes or substitutions are possible in the exemplary embodiments without materially departing from the novel teachings and advantages of the present disclosure. Accordingly, all such modifications, changes or substitutions are intended to be included within the scope of this disclosure as defined in the following claims. In the claims, means-plus-function clauses are intended to cover the structures described herein as performing the recited function and not only structural equivalents, but also equivalent structures.
This application claims the benefit of the filing date of U.S. provisional patent application No. 61/429,515, filed Jan. 4, 2011, the entire disclosure of which is incorporated herein by reference. This application is a continuation of co-pending international application number PCT/US12/20087, filed Jan. 3, 2012, which claims priority to U.S. provisional patent application No. 61/429,515, filed Jan. 4, 2011, the entire disclosures of which are incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 61429515 | Jan 2011 | US | |
| 61429515 | Jan 2011 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/US12/20087 | Jan 2012 | US |
| Child | 13343174 | US |
