Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
  • F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
  • F01L1/34—Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of means for changing the timing of the valves without changing the duration of opening and without affecting the magnitude of the valve lift
  • F01L1/344—Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of means for changing the timing of the valves without changing the duration of opening and without affecting the magnitude of the valve lift changing the angular relationship between crankshaft and camshaft, e.g. using helicoidal gear
  • F01L1/3442—Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of means for changing the timing of the valves without changing the duration of opening and without affecting the magnitude of the valve lift changing the angular relationship between crankshaft and camshaft, e.g. using helicoidal gear using hydraulic chambers with variable volume to transmit the rotating force
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
  • F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
  • F01L1/34—Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of means for changing the timing of the valves without changing the duration of opening and without affecting the magnitude of the valve lift
  • F01L1/344—Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of means for changing the timing of the valves without changing the duration of opening and without affecting the magnitude of the valve lift changing the angular relationship between crankshaft and camshaft, e.g. using helicoidal gear
  • F01L1/3442—Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of means for changing the timing of the valves without changing the duration of opening and without affecting the magnitude of the valve lift changing the angular relationship between crankshaft and camshaft, e.g. using helicoidal gear using hydraulic chambers with variable volume to transmit the rotating force
  • F01L2001/3445—Details relating to the hydraulic means for changing the angular relationship
  • F01L2001/34483—Phaser return springs

Definitions

• the invention relates to an adjusting device for camshafts, which are used in internal combustion engines, such as motor vehicles, according to the preamble of claim 1.
• Camshaft adjusters have the task of changing the position of a camshaft of an internal combustion engine. This influences the opening and closing times or the opening width of a gas exchange valve of the internal combustion engine.
• camshaft adjusters There are numerous designs of camshaft adjusters.
• camshaft adjusters are known which move a hydraulic piston in the axial direction.
• helically toothed camshaft adjusters are known.
• Another type of camshaft adjuster works like a hydraulic swivel motor which is equipped with at least one stator and with at least one rotor.
• the stator forms the fixed reference point, which, however, can be in rotation as a whole.
• the rotor changes its position relatively to the fixed reference point of the stator.
• a camshaft to be adjusted is connected directly or indirectly to the rotor. If the rotor changes its position relative to the stator, the position of the cams on the camshaft also changes.
• camshaft adjusters are operated with an oil.
• a special hydraulic oil or the normal engine oil of the internal combustion engine can be used for this.
• the camshaft may be striving for a less favorable position.
• the system of internal combustion engine and camshaft adjuster is designed for the regular operating state. It means that at lower temperatures, especially in the cold season, the viscosity of the oil used, for example engine oil or hydraulic oil, is too low.
• DE 198 60 418 AI also uses a spring which interacts with a locking element.
• An angle limiting groove is provided in a side wall.
• the angle limiting groove has groove ends which are designed as angle limiting stops.
• a stop bolt can adjust the impeller relative to the drive wheel in the pivoting angle formed by the angle limiting groove.
• DE 196 06 724 AI and DE 102 13 831 AI variable valve timing devices are described, which are equipped with two engagement elements are.
• DE 196 06 724 AI presents a camshaft adjuster that moves the adjusting piston in the axial direction.
• the adjusting piston works with a helical toothed section.
• DE 102 13 831 AI proposes to use a lagging pin and a locking pin. When a motor stalls, the rotor should generally move to the most lagging angular position and stop there to make it difficult to restart the motor. With the lag angle limiting pin, this can only be done to a certain extent.
• the hydraulic circuit diagrams in particular make it clear that this system must be equipped with several chambers in order for it to work. Every hydraulic engineer understandably tries to reduce the number of chambers as much as possible. A designer, on the other hand, wishes to keep the number of components and the volume converted as small as possible.
• the camshaft adjuster according to the invention which can be used in internal combustion engines, has at least two chambers whose volume can be changed and which are designed in opposite directions. If the volume of one chamber is increased, the volume of the corresponding second chamber automatically decreases accordingly and vice versa.
• the camshaft adjuster has a starter and a rotor. The stator and rotor can be moved relative to one another. A suspension for a camshaft is provided in the rotor. The position of the rotor relative to the stator can be changed by means of oil pressure that can be introduced into the chambers. As a result, the camshaft adjuster adjusts the camshaft.
• the camshaft adjuster thus adjusts the angle of the camshaft relative to a crankshaft of the internal combustion engine by means of a relative rotation.
• the camshaft adjuster follows one of at least two characteristic curves provided. If the camshaft adjuster follows one characteristic curve, it cannot follow the other characteristic curve at the same time. It therefore follows the characteristic curves alternately.
• the exact position of the relative rotation is varied by the oil pressure, which is usually in a range below 1 bar.
• the choice of which characteristic curve to follow determines the influencing variable. If the state of the influencing variable is undershot, for which the camshaft adjuster is designed due to its mechanical elements, the locking mechanism engages at the freely selectable locking position.
• the camshaft adjuster is equipped with a mechanical stop.
• the stop forms a stop position. As soon as a certain preload force is exceeded, the stop can be moved. The stop is firmly anchored below the preload. In this case, the stop cannot be moved, but is stationary.
• the camshaft adjuster is equipped with various stops. It is known in the prior art that a camshaft adjuster has a minimum and a maximum Can take position. That is the early position and the late position. The positions are determined by mechanically fixed stops. In between there is a movable position. The displaceable position, which is determined by a stop, can assume a fixed, locked position.
• Torques are introduced into the camshaft adjuster.
• the torque is introduced by the camshaft or by changing the oil pressure in the chambers. There is often a double introduction.
• a counter torque is formed for this.
• the counter torque is implemented mechanically.
• At least one of the two characteristic curves is implemented in the camshaft adjuster with simple mechanical means.
• the at least two existing characteristic curves can also preferably be implemented by a combination of mechanical components or elements.
• the stator and the rotor together form a hydraulic swivel motor.
• the stator is equipped with bars.
• the webs limit the angular range that the rotor can cover.
• Swing motors are often designed so that they can cover between 0 ° and 30 °.
• a swivel motor is preferably designed for a maximum angular range, which can be 22 °, for example.
• a receptacle for a camshaft is provided which can rotate in rotation. The receptacle is often placed around the center point or the center axis of the camshaft adjuster. The rotor rotates relative to the stator. It rotates the camshaft with it.
• the selected influencing variable can be an engine oil pressure or an oil pressure of the internal combustion engine, a temperature of the internal combustion engine or the speed of the internal combustion engine, which in turn influence the oil pressure.
• the internal combustion engine can also advantageously be constructed in such a way that it follows a combination of different parameters. Due to the influencing variable, there is a change between different characteristics.
• These characteristic curves can be a continuous operating characteristic curve, a starting operating characteristic curve, a switch-off characteristic curve or an idling characteristic curve. It is also conceivable that the start operating characteristic and the idling characteristic are identical.
• the two implemented characteristic curves are continuously superimposed piece by piece, the second characteristic curve having at least one discontinuous point, a discontinuous jump, due to a locking pin or a locking mechanism.
• the characteristic curve is thus divided into two areas, an area that is independent of the oil pressure and an area that is dependent on an influencing variable, such as the oil pressure.
• the characteristic curve has no gradient in the independent area.
• a spiral spring is used in the camshaft adjuster.
• a locking pin is equipped with another spring.
• Two springs work against the oil pressure inside the camshaft adjuster.
• One spring is a spiral spring and the other spring is a cylindrical helical compression spring.
• the rotor and the stator together form a swivel motor.
• the stator has webs that point from the edge of the stator to the center of the swivel motor. In the broadest sense, the stator could be compared to a spoke wheel.
• the rotor is encompassed by the stator. It lies towards the center of the stator. The stator webs point towards the center, but they do not come together even in the middle.
• the rotor and stator together form hydraulic chambers, the size and volume of which can be changed by pivoting the rotor. In operation, the hydraulic chambers are filled with a hydraulic medium, such as a hydraulic oil or an engine oil. The hydraulic medium is pressurized. The position of the rotor changes depending on the pressure ratio in the respective chambers.
• the rotor has wings. So a rotor alone looks like a star. Because the hydraulic medium exerts different pressure on the sides of the blades of the rotor, the blades move in one or the other the other direction.
• the camshaft adjuster is also equipped with a spring.
• the camshaft adjuster has a locking device.
• the locking device can consist of a pure locking pin.
• numerous locking devices are known from the prior art, which include a pin, a spring and a hydraulic cylinder.
• the spring mentioned above differs from the spring of the locking pin.
• the spring of the first type is supported on the stator due to a mechanically strong connection to the stator. Alternatively, it can also have a press fit.
• the driver can be designed in the form of a driver disk. If you look at the drive plate from the installation direction, the drive plate has the shape of a closed ring. At some points on the drive plate, it has bulges. They are also called gears.
• the teeth lie on the inner and / or outer edge of the ring-like drive plate. The teeth are designed to engage either in the rotor or in the stator. So that the toothing is in engagement with the stator or the rotor, they are directed towards the inside with the rotor, or towards the outside of the ring for the stator.
• the rotor and the stator offer larger cutouts in the engagement area.
• the toothing and recesses can lie on different, parallel planes in the camshaft adjuster. They have the appearance of two staggered, overlapping rings.
• the cutouts provide the rotor or stator with a freewheel area. Because the rotor and stator overall have a predominantly round design, the freewheel area can be referred to as the notch in the drive plate.
• the shape of the drive plate together with the spring, which is supported at one point of the stator shape the course of one or both characteristic curves. By a clever design of the drive plate or the spring winding, the course of the Counter torque influences and determines. It then has the form as it was shown in the characteristic curve.
• a horizontally designed spiral spring is particularly popular for the firmly anchored spring.
• the spiral spring surrounds the common center or center axis of the swivel motor with the spring steel. It is parallel to the rotor. This type of spring, which is small in width, prevents tensioning, balancing or sluggishness.
• the locking pin is provided with a spring in the form of a locking device, so that the locking pin is pretensioned.
• the locking pin can be arranged in a wing. It is also conceivable that the locking pin lies in a web of the stator. When the pressure of the hydraulic medium in the area of the locking pin falls below a minimum pressure, the locking pin moves into a position in which the rotor is anchored to the stator. It is advantageous if the anchoring takes place with little play. The rotor then shows essentially no movement other than the stator when it is locked. In this case, the rotor and stator run synchronously.
• the pressure conditions in the swivel motor need not be taken into account.
• the rotor therefore has the same rotational movement as the stator, regardless of the pressure.
• a separate valve which does not form a unit with the camshaft adjuster, but is only connected hydraulically, can be provided for the locking device.
• the hydraulic valve is controlled depending on a parameter, such as the pressure conditions in the swivel motor or the speed or temperature.
• the additional valve thus determines the locking point.
• the camshaft adjuster is equipped with a cover.
• the cover is fastened to the stator using countersunk fasteners, in particular countersunk screws.
• the opposite side of the camshaft adjuster is covered by a sprocket.
• the sprocket is vertical or at right angles on the central axis of the camshaft adjuster.
• the sprocket and the cover thus form the two outer limits of the camshaft adjuster.
• the spring that determines the counter torque is connected to the driver at its other end, the end that is not connected to the stator, in an alternative embodiment the spring is located under the cover of the stator.
• the other end of the spring opens into a ring.
• the ring has an opening.
• the jaws of the ring surround the bearing of the rotor.
• FIG. 3 shows a schematic embodiment with a driver, which is otherwise very similar to the camshaft adjuster according to FIGS. 4-9,
• FIG. 4 shows a view of an embodiment of a camshaft adjuster according to the invention
• FIG. 5 shows the camshaft adjuster along the section A-A of FIG. 4,
• FIG. 6 shows along the section B-B of the camshaft adjuster according to FIG. 4
• FIG. 9 shows the camshaft adjuster of FIG. 4 along the other side but without a cover.
• the abscissa shows the adjustment of the camshaft in relation to the crankshaft displayed.
• the abscissa is characterized by at least three points.
• the characteristic curve moves between the early position Y and the late position Z.
• a selected idle position L and a start position X are indicated.
• the pressure of the hydraulic medium P is given in bar on the ordinate.
• the input pressure of the system oil supply can also be entered here.
• the characteristic curve thus establishes a relationship between the angular adjustment of the crankshaft, a torque of the camshaft and a pressure.
• a counter torque is formed with increasing torque.
• the inclination of the characteristic curve U is determined by the return spring 200 from FIG.
• the return spring has no effect.
• the return spring 200 acts in the form of the inclination U.
• the position of the starting position X is set by the locking device. It can be placed on any point between the early position Y and the late position Z by the optimal choice of the return spring and the locking device. It is determined exclusively by the requirements of the internal combustion engine.
• the pressure assigned to the starting position X is referred to as PI. It is usually in a pressure range between 0.5 and 1 bar. Alternatively, it can also be below and above.
• the point assigned to the late position is shown as P2 in the characteristic curve of FIG. 1.
• the pressure that should be at idle position L is referred to as P3.
• the characteristic curve has a point of discontinuity.
• the counter moment can only act when the pressure changes. Because of the point of discontinuity one can speak of two moment characteristics. There is a first characteristic curve in which the spring torque does not apply. There is a second moment when the discontinuity is skipped.
• the characteristic curve shows a nomenclature that is common to the applicant and her numerous customers in the automotive industry.
• a variant that is also used is the representation of the difference angle between the crankshaft and the camshaft.
• Another variant is the relative reference only to the crankshaft. If the locking pin is adjusted, the rotor follows the stator in one direction of rotation, while in the other direction of rotation a freewheel is made possible. Only work against the spring when the stop position is reached
• the linearized hydraulic cylinder 1 has a housing 7. It is equipped with a helical spring 3 which is supported with respect to the bearing 5. The piston surface 9 and the stop 11 act in opposite directions, the stop surface of the stop 11 counteracting the bias of the spring 3 got to.
• the piston 13 with the piston surface 9 is equipped with a compensating or venting line 15.
• the piston 13 is equipped with a locking mechanism which is equipped with a locking pin 19 and a biasing spring 23 for the locking pin 19. The spring 23 clamps the locking pin 19 against the housing 7 below a pressure of the hydraulic medium. In the locking state shown in FIG.
• the locking pin 19 prevents the piston 13 from freewheeling when the locking pin against the housing wall within the projection 17 or the freewheel region 17, stops. Under pressure, that is when the hydraulic medium is printed, the hydraulic medium presses the locking pin 19 against the biasing spring 23 via the control line 21 and thus lifts the locking pin out of its catch. The piston can then run free from a first stop to a second stop.
• the freewheel area 17 is delimited by a guide surface which is in a different plane than the cutting plane shown in the schematically represented FIG. 2.
• FIG 3 shows a schematic configuration of a rotor 350 according to the invention.
• the top, inner level of a camshaft adjuster according to the invention is shown on the left-hand side. The level has broken open to the right. In the plane that lies below, the rotor 350 has a different shape, so that space is still created for a driver 300.
• the ends 204 and 202 of the spring 200 are fastened to the stator 100 and driver 300, respectively.
• the driver 300 has teeth, two of which have been shown 302, 304. One tooth engages in the rotor 350, the other tooth locks against the stator 100, preferably at a different circle position of the driver disk. Teeth 302, 304 can be at different heights.
• the other parts of the camshaft adjuster 51 essentially correspond to the parts shown in FIGS. 4, 5, 6, 7 and 8.
• FIG. 4 shows a camshaft adjuster 50 according to the invention. It is shown from the side of the sprocket 52, which is provided with teeth all around, such as tooth 54.
• the sprocket has a marking 48 which represents the zero position.
• the sprocket 52 is fixed by a cylindrical pin 70.
• the first bore 60, the second bore 62, the third bore 64, the fourth bore 66 and the fifth bore 68 are embedded in the webs 110, 112, 114, 116, 118 of the stator 100, which also forms part of the housing ,
• the bores 60, 62, 64, 66, 68 are receptacles for countersunk fasteners intended.
• Such countersunk fasteners are, for example, countersunk screws of sizes M4, M5, M6, M7.
• the camshaft adjuster 50 is shown in FIG. 5 from a different point of view.
• the position of the rotor 120, which forms the suspension 90, can be seen in this illustration.
• the coil spring 200 can be seen, which is placed in a special space around the receptacle 90.
• a cover disk 78 covers the rotor 120 and the stator 100, through which bores for the countersunk fasteners 64 are also made.
• FIG. 6 shows the camshaft adjuster 50 along the section BB of FIG. 5.
• the camshaft adjuster 50 shows the webs which are designated 110 for the first, 112 for the second, 114 for the third, 116 for the fourth and 118 for the fifth web.
• the rotor 120 is in one position so that chambers of the first and second types are formed.
• the chambers of the second type 170, 172, 174, 176, 178 are a minimum.
• the chambers of the first type 160, 162, 164, 166, 168 are in their maximum extent.
• the hydraulic medium can circulate through channels 150, 152, 154, * 156, 158.
• the vanes 122, 124, 126, 128, 130 move in the hydraulic medium and are moved back and forth between the respective associated webs 110, 112, 114, 116, 118 by the rotation of the rotor 120.
• channels 220 which is a first channel, 222 for the second channel, 224 for a third channel and 226 and 228 for a fourth and a fifth channel. Otherwise, the components are similar to FIG. 6.
• the locking device can be seen very well in FIG. 8. It comprises the locking bolt 190, which is a stepped bolt here, and is biased by a spring plate 192 together with a spring 194. The stepped bolt is guided in the locking guide 140.
• the spiral spring 200 of the camshaft adjuster 50 is shown from the side opposite to FIG. 4.
• One end of the coil spring 202 is supported against the Cover plate 78 and is officiated by the notch 208.
• the other end 204 of the spiral spring 200 opens into the ring 206 which encompasses the bearing of the rotor 210.
• the tooth 302 is shown in the figure, which is shown in a stop position.
• the freewheel area begins, which allows the rotor to rotate without spring and thus without torque. The additional counter torque of the spring must only be overcome when the stop is in the other position.
• the spring In the unlocked state, the free state, the spring generates a spring torque that increases when the camshaft to be picked up in the internal combustion engine strives towards its late position. If the camshaft adjuster is only supplied with only one hydraulic medium for the chambers and or the locking bolts, the locking is released at a pressure threshold X, from which in area II the spring torque acts or stands in a linear relationship between the crankshaft rotation angle and the pressurization.
• the locking position for a camshaft adjuster is determined by the choice of the springs, the design of the locking bolt and the dimensions of the engagement mechanisms.
• An adjuster according to the invention shows a behavior on a static test bench that essentially corresponds to the characteristic curve according to FIG. 1.
• individual adjustment angles are approached by changeable pressurization.
• the adjustment angle is recorded.
• point X of FIG. 1 which is dependent on the oil pressure, the locking pin locks in.
• area II of the characteristic curve the counter torque is to be measured as a function of the oil pressure.
• An object according to the invention can thus be equipped with a separate drive plate, but the drive functionality can also be present in suitable other components. Because of the unmistakable advantages of a swivel motor, the invention is described with different characteristics for the swivel motor or for the camshaft adjuster depending on the operating state in such an embodiment, but it goes without saying that a person skilled in the art will develop an axial piston or helical gear variant of the camshaft adjuster based on this Can develop invention.
• camshaft 100 mounting for camshaft 100 ... stator 110, 112, 114, 116, 118 ... webs 120 ... rotor 122, 124, 126, 128, 130 ... wing 140 ... locking guide 150, 152 , 154, 156, 158 ... oil channel, to chambers 160, 162, 164, 166, 168 ... chambers, of the first type 170, 172, 174, 176, 178 ... chambers, of the second type 19 0 ... stepped bolt 192 ... spring washer

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Valve Device For Special Equipments (AREA)
• Valve-Gear Or Valve Arrangements (AREA)

Applications Claiming Priority (2)

Publications (1)

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Family Applications (1)

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• 2004
  • 2004-03-11 DE DE102004012460A patent/DE102004012460B3/de not_active Expired - Fee Related
  • 2004-12-16 WO PCT/EP2004/053531 patent/WO2005088081A2/de active Application Filing
  • 2004-12-16 EP EP04821411A patent/EP1723315A2/de not_active Withdrawn
  • 2004-12-16 CN CNA2004800423848A patent/CN101115910A/zh active Pending
  • 2004-12-16 JP JP2007502202A patent/JP2007528961A/ja active Pending
• 2006
  • 2006-03-06 US US11/369,519 patent/US7278385B2/en not_active Expired - Fee Related

Non-Patent Citations (1)

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