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
  • F01L13/00—Modifications of valve-gear to facilitate reversing, braking, starting, changing compression ratio, or other specific operations
  • F01L13/0015—Modifications of valve-gear to facilitate reversing, braking, starting, changing compression ratio, or other specific operations for optimising engine performances by modifying valve lift according to various working parameters, e.g. rotational speed, load, torque
  • F01L13/0036—Modifications of valve-gear to facilitate reversing, braking, starting, changing compression ratio, or other specific operations for optimising engine performances by modifying valve lift according to various working parameters, e.g. rotational speed, load, torque the valves being driven by two or more cams with different shape, size or timing or a single cam profiled in axial and radial direction
• • 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
  • F01L2820/00—Details on specific features characterising valve gear arrangements
  • F01L2820/03—Auxiliary actuators
  • F01L2820/031—Electromagnets
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T74/00—Machine element or mechanism
  • Y10T74/21—Elements
  • Y10T74/2101—Cams
  • Y10T74/2107—Follower

Definitions

• the invention relates to a switchable valve actuation mechanism, as used for example in reciprocating internal combustion engines for switching the timing of an intake valve.
• Switchable valve actuation mechanisms are in many ways in use and serve to adjust the timing of different operating conditions to influence the power delivery, the torque behavior and the exhaust gas behavior of the internal combustion engine low.
• a switchable valve actuating mechanism is known from DE 102 30 108 B4.
• a bearing pin is rotatably mounted on the valve lever, which has two with respect to its axis of rotation eccentric bearing sections, on each of which a cam of the camshaft scanning cam roller is mounted.
• the bearing pin is non-rotatably connected to a friction disc whose outer circumference for rotating the bearing pin is in frictional engagement with a circumferential surface of the camshaft. The rotatability of the friction disc can be blocked in different rotational positions.
• the invention has for its object to provide a switchable valve actuation mechanism which operates in a compact design with low friction and allows safe switching of the valve actuation of a cam of a camshaft to another cam of the camshaft.
• the first sensing member scans the contour of the first cam while the rotatability of the eccentric is released, so that the eccentric for scanning the second sensing member only has to be rotated by a predetermined rotational position in which its rotatability is locked. Additional components with which the eccentric is twisted, are not required.
• the subclaims are directed to advantageous embodiments and developments of the valve actuating mechanism according to the invention.
• the dependent claims 2 to 4 indicate an advantageous construction of the eccentric and the first Abtastbauteils.
• the claim 5 indicates an advantageous embodiment of the second Abtastbauteils.
• the claims 6 to 10 are directed to features of the valve actuating mechanism according to the invention, with which a mobility of the eccentric is achieved in its lockable rotational position and out of the lockable rotational position in a particularly simple manner.
• valve lever is loaded symmetrically.
• the invention which can be used for substantially all types of camshaft actuated valves and a changeover between two different opening curves, one of which may be a zero actuation allowed, will be explained below with reference to schematic drawings, for example and with further details.
• FIG. 1 is an overall perspective view of a valve actuating mechanism
• FIGS. 4 and 5 show different perspective views of a valve lever with associated components
• 6 is a perspective view of a connecting lever
• FIG. 7 to 9 different perspective views similar to FIG. 1 in different functional states
• Figures 10 to 13 are side views of 4 with respect to a spring device different embodiments of the valve actuating mechanism in each case in two different positions.
• a charge exchange valve 2 for example an intake valve of an internal combustion engine, is actuated by a camshaft 4 with the interposition of a valve lever 6.
• the valve lever 6 is supported at one end on a known hydraulic lash adjuster element 8 and at the other end on the shaft of the valve 2 and is located between its ends in still closer to discussing way to cams 12 and 14 at.
• a middle first cam 12 is designed with a smaller elevation than lateral second cam 14, which receive the first cam 12 between them.
• a valve closing spring is designated 16.
• the hydraulic valve clearance compensation element 8 causes the valve lever 6 is in play-free engagement with at least one of the cams and the shaft of the valve.
• Fig. 2 shows the valve lever 6 and the components mounted on it in exploded perspective view.
• the valve lever 6 has two end regions 18 and 20, which are connected to one another via mutually spaced side parts 22. Through the side members 22 passes through a bushing receiving opening 24 into which a socket 26 is inserted.
• the end portion 18, which rests on the lash adjuster element 8, is hollow on the inside and has a lateral opening 28.
• a stop 30 is formed on the left side of the end region 18 at the bottom.
• an eccentric 32 is used along the circular cylindrical outer circumference rolling elements 34 are arranged so that the eccentric 32 is rotatable in the sleeve 26.
• a scanning ring or a cam follower 38 is used, the inside of which is provided with rolling elements, not shown, by means of which the cam follower 38 is mounted in the pushed onto the sleeve 26 state on this.
• a hole 40 of a connecting lever 42 can be pushed, which has a slot 44 formed with a lateral projection 46 (Fig. 6), which fits into a passage opening 48 of the eccentric 32.
• the connecting lever 42 has a recess 50 and a contact surface 52 at one end region.
• a torsion spring 54 can be inserted, which can engage with an end leg (not shown) in the slot 44 of the connecting lever and with its other end leg 55 can be supported on a projection 56 of the valve lever 6 (see FIGS .. 4, 8 and 9).
• cam followers 58 can be stored by means provided in the cam rollers 58 bearings.
• the cam followers 58 are advantageously arranged on the bearing pin 36 between annular discs 60, wherein the outer annular discs 60 are advantageously formed as retaining rings which secure the cam followers 58 axially on the bearing pin 36.
• the end portion 18 of the valve lever 6 has a cylindrical cavity 62, which ends in FIG. 3 to the left in the opening 28 and merges into a bore 64 to the right.
• a generally U-shaped in cross-section piston 66 is used, which is held by means of a piston penetrating the piston head and screwed into the bore 64 pin 68. Between the pin 68 and the piston 66, a spring 70 is supported.
• a according to FIG. 3 right of the piston head befind Anlagen part of the cavity 62 is connected via a Passage 72 is connected to a recess 74 with which the valve lever 6 rests on the valve clearance compensation element 8. The passage 72 and thus the piston 66 can be acted upon by the valve clearance compensation element 8 with hydraulic pressure.
• Fig. 2 The assembly of the components shown in Fig. 2 is for example as follows:
• the cam follower 38 is inserted into the slot 37 of the connecting lever 42. Subsequently, the sleeve 26 is inserted, so that the sleeve is held in the recesses 50 and the cam follower 38 is rotatably mounted on the sleeve 26. In the socket 26 of the eccentric 32 is inserted, so that the eccentric 32 is rotatable about the axis of the sleeve 26 in total. In the through hole 48 of the eccentric 32, the torsion spring 54 is inserted. Subsequently, from one side of the connecting lever 42 and a cam follower 58 and on the other bearing pin 36, the other cam follower 58 is pushed, optionally annular discs are placed therebetween. The cam followers 58 are secured by means of circlips on the bearing pin 36.
• the piston 66 is inserted and secured by means of the pin 68 with the intermediate arrangement of the spring 70.
• the resulting assembly is placed on the lash adjuster 8 and the stem of the valve 2.
• the legs of the torsion spring 54 are suspended in such a way that the connecting lever 42 or the eccentric 32, which is non-rotatably connected to the connecting lever 42, are biased for rotation in the clockwise direction, ie. that the cam followers 58 are biased in abutment with the associated second cam 14.
• the connecting lever 42 can pivot in the clockwise direction until its contact surface 52 bears against the stop 30.
• the recess 50 is aligned with the opening 28, so that the piston 66 can extend by applying hydraulic pressure and retract into the recess 50, whereby the connecting lever 42 is locked relative to the valve lever 6.
• the valve lever 6 is operated according to the larger elevations of the second cam 14, wherein the first cam 12 is released from the cam follower 38.
• the blocking of the connecting lever 42 can be achieved by lowering the pressure acting on the piston 66 hydraulic pressure, when the cam base circle in turn passes over the cam followers 58 and the piston is urged back by the spring 70 in the valve lever 6.
• the connecting lever 42 is provided in the region of the contact surface 52 with an inclined surface 76 (FIG. 4), which ensures that the piston 66 acting as a bolt is pushed back against the stop 30 when the connecting lever 42 is pivoted.
• FIGS. 7 to 9 show the arrangement of FIG. 1 in different perspective views and functional states.
• Fig. 7 shows a position where the second cams are ineffective, i. the connecting lever is unlocked.
• FIGS. 8 and 9 show a zero stroke position and an approximately full stroke position when the connection lever is locked.
• the switchable valve operating mechanism of the present invention is very compact and has low moving masses and high rigidity. Furthermore, the tapping of the cam on the stored cam followers 58 and 38, which leads to low friction and thus consumption advantages.
• FIG. 10 shows an embodiment modified from the described embodiment in a side view similar to the view according to FIG. 4.
• a curved coil spring 80 is used instead of the torsion spring (s), which is supported between the valve lever 6 formed on the projection 56 and stop and a further stop 82 which is rigidly fixed to the eccentric 32 and beyond is connected to the connecting lever 42.
• the state of the helical spring 80 is shown in the case of the cam roller 58 resting against the cam base circle.
• the state is shown in which the coil spring 80 is compressed to the maximum, so that it holds the cam follower in safe engagement with the cam after passing over the cam follower 58 by the cam 14.
• a rocker arm 88 mounted on the valve lever 6 is used, whose one end scans the rotation of the eccentric 32 or the movement of a bearing journal 36 rigidly connected thereto and between the other end thereof and the valve lever 6, a coil spring 8O 2 is supported. Otherwise, the function of the embodiment according to FIG. 13 corresponds to that of FIG. 12.
• return springs described above are exemplary only and may be varied and / or combined in a variety of ways.
• the valve actuating mechanism according to the invention can be modified in many ways.
• the blocking of the rotatability of the eccentric can be done electromagnetically or otherwise. It does not necessarily have to be provided three cams and three cam rollers. However, the illustrated embodiment ensures high symmetry and freedom from tilting forces that want to tilt the valve lever about its longitudinal axis.
• the adjustable tapping mechanism need not necessarily be located between the motor housing fixed support and the support on the valve of the lever.
• the cam contours sensing components need not necessarily be rotatably mounted, but could also be formed directly on the socket and the journals. However, the described rotatable mounting of the components in direct contact with the cam and the rotatable mounting of the eccentric within the valve lever have the advantage of very low friction and high durability.
• the direction of rotation of the eccentric can be reversed compared to the subjects.
• the connecting lever and the spring (s) may be arranged on the same or different sides of the valve lever, etc.

Landscapes

• 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 (3)

Publications (1)

Family

ID=37309261

Family Applications (1)

Country Status (5)

Families Citing this family (19)

Family Cites Families (21)

• 2005
  • 2005-08-19 DE DE102005039368A patent/DE102005039368B9/de not_active Expired - Fee Related
• 2006
  • 2006-07-26 JP JP2008525425A patent/JP4982492B2/ja not_active Expired - Fee Related
  • 2006-07-26 WO PCT/EP2006/007365 patent/WO2007017109A1/de active Application Filing
  • 2006-07-26 EP EP06776422A patent/EP1913240A1/de not_active Withdrawn
  • 2006-07-26 US US12/063,217 patent/US7963260B2/en not_active Expired - Fee Related

Non-Patent Citations (1)

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