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
  • F01L1/26—Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of two or more valves operated simultaneously by same transmitting-gear; peculiar to machines or engines with more than two lift-valves per cylinder
  • F01L1/267—Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of two or more valves operated simultaneously by same transmitting-gear; peculiar to machines or engines with more than two lift-valves per cylinder with means for varying the timing or the lift of the valves
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
  • F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
  • F01L1/02—Valve drive
  • F01L1/04—Valve drive by means of cams, camshafts, cam discs, eccentrics or the like
  • F01L1/08—Shape of cams
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
  • F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
  • F01L1/12—Transmitting gear between valve drive and valve
  • F01L1/18—Rocking arms or levers
  • F01L1/181—Centre pivot rocking arms
• • 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
  • F01L13/06—Modifications of valve-gear to facilitate reversing, braking, starting, changing compression ratio, or other specific operations for braking
  • F01L13/065—Compression release engine retarders of the "Jacobs Manufacturing" type
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
  • F01L2305/00—Valve arrangements comprising rollers

Definitions

• the invention relates to a valve drive for piston internal combustion engines with at least one control cam, an additional cam, a first rocker arm and a second rocker arm, which are pivotably mounted on a rocker arm shaft, the first rocker arm being in operative contact with at least a first cylinder valve, at least the auxiliary cam is in operative contact with the second rocker arm and the second rocker arm can be brought into force flow with the first rocker arm via an actuating element.
• a braking device with a cam-driven exhaust valve is already known from DE 15 26 485.
• an auxiliary rotary cam device with a hydraulically operated locking piston is provided, which ensures the flow of force between an auxiliary cam and the rocker arm by actuating the locking piston arranged within the rocker arm.
• a rocker arm cam arrangement with a first control cam and a second control cam is shown on page 12.
• the control cams are each operatively connected to a cylinder valve via a rocker arm pivotally mounted on a rocker arm shaft.
• An additional control cam is assigned a further rocker arm, which has a controlling actuator can be positively connected to the rocker arms. The actuator is moved axially to the rocker arm axis.
• the invention is based on the object of designing and arranging a valve drive in such a way that flexible control of an engine valve is ensured.
• control cam is in operative contact with the second rocker arm. This ensures that only the second rocker arm is to be brought into operative contact with the control cam and the additional cam or with the control drive.
• the control cam and the additional cam are arranged on a common cam track, which overall simplifies the design of the control drive. Active contact means that in addition to a possible lubricant film and / or a play compensation element, there is direct contact between the respective gear parts.
• a brake system based on the valve drive according to the invention can also be implemented in newer engine designs. A constant throttle is no longer necessary. In addition to the simple design, the installation space is optimally used.
• the valve drive according to the invention can also be used with camshafts located below and above.
• the actuating element has a locking direction which corresponds to the direction of a locking force acting between the first rocker arm and the second rocker arm and the locking direction is arranged perpendicular to and at a distance from the rocker shaft with respect to a central axis. Due to the distance of the blocking direction or the blocking force from the central axis of the rocker arm shaft, a lever can be realized which can be optimally designed according to the control forces to be applied.
• the adjustment paths of the Adjusting elements are proportional to the distance to the central axis and thus can also be changed with the distance to the central axis.
• an additional possibility is that between the first rocker arm and the second rocker arm there is an empty angle ⁇ that can be adjusted with reference to a pivoting movement on the rocker arm shaft by the adjusting element.
• the control path of the cylinder paths generated by the control cams or auxiliary cams can be set or changed.
• the empty angle of ⁇ 0 °
• the first rocker arm follows the second rocker arm, with the empty angle ⁇ increasing, on the one hand, a delay in the actuating movement of the first rocker arm and, on the other hand, limiting the overall actuating angle of the first rocker arm.
• the actuating element is designed as a movable piston and is connected to a control line and a control valve for pressure medium.
• the design of the control element as a hydraulically operated piston ensures simple and wear-free control.
• control line has a check valve to which a bypass line is assigned.
• a check valve ensures, on the one hand, the pressure build-up within the control line when the control valve is closed. On the other hand, pressure medium can flow in via the bypass line if pressure medium is lost within the control line.
• the piston is arranged movably within a pressure medium cylinder connected to the control line and with a first end face against the first rocker arm can be applied directly or indirectly.
• the control valve When the control valve is closed, a relative movement between the piston and the pressure medium cylinder is prevented, so that the actuating movement of the second rocker arm is at least partially transmitted to the first rocker arm.
• the control valve When the control valve is open, the pressure medium volume of the pressure medium cylinder is reduced and the second rocker arm executes an idle travel until the control valve closes, during which the first rocker arm remains in its rest position.
• a return element counteracting the pressure force of the pressure medium is assigned to the piston within the pressure medium cylinder.
• the return element initiates the return movement of the piston immediately after opening the control valve, thus preventing dynamic pressure surges on the first rocker arm.
• first rocker arm is pivotably mounted on the rocker arm shaft or on the second rocker arm.
• a non-illustrated bypass line is assigned to the check valve, via which pressure medium is drawn in. It is also advantageous that the first rocker arm, the actuating element and the second rocker arm form a structural unit.
• either the control cam is in operative contact with the first rocker arm and the additional cam is only in operative contact with the second rocker arm.
• the additional cam By directly actuating the first rocker arm, only the braking operation would be implemented via the second rocker arm and the control element.
• a further control cam could be used if necessary by activating the control element. This can be an engine-saving mode or high-performance engine mode can be realized, which in addition to the usual shape of the control cam requires a changed shape of the control cam.
• Fig. 1 is a schematic representation of the valve drive from above with the first rocker arm, second rocker arm and
• Fig. 2 is a schematic representation of the valve drive from the side with the first rocker arm, second rocker arm and
• Fig. 3 is a schematic diagram of the flow of force between the first
• Rocker arm, second rocker arm, control cam, auxiliary cam and cylinder valve Rocker arm, second rocker arm, control cam, auxiliary cam and cylinder valve.
• the valve drive 1 essentially has a first rocker arm 2.1 and a second rocker arm 2.2, which are pivotably arranged on a rocker arm shaft 2.
• the first rocker arm 2.1 is assigned a first cylinder valve 3.1 and a second cylinder valve 3.2, which are actuated when the first rocker arm 2.1 pivots about the rocker arm shaft 2 or its central axis 2.3.
• the first rocker arm 2.1 and the second rocker arm 2.2 are arranged one behind the other with reference to the central axis 2.3 of the rocker arm shaft 2 and can be mechanically coupled via an adjusting element 5 designed as a piston.
• the piston 5 is here slidably supported within a pressure medium cylinder 9 of the second rocker arm 2.2.
• the pressure medium cylinder 9 is operatively connected via a control line 6 to a control valve 7 and a check valve 8.
• the actuating piston 5 lies with its end face 5.1 opposite the pressure medium cylinder 9 against a stop surface 5.2 of the second rocker arm 2.2 or can be placed against it.
• the restoring element 10 which is designed as a spring element, ensures a restoring movement of the actuating piston within the pressure medium cylinder 9 when the control valve 7 is open transfer the control piston 5 with the control valve 7 closed to the first rocker arm 2.1 and thus to the first cylinder valve 3.1 and the second cylinder valve 3.2.
• the restoring element 10 ensures a restoring movement of the actuating piston within the pressure medium cylinder 9 when the control valve 7 is open transfer the control piston 5 with the control valve 7 closed to the first rocker arm 2.1 and thus to the first cylinder valve 3.1 and the second cylinder valve 3.2.
• Only part of the pivoting movement carried out by the second rocker arm 2.2 can thus be transmitted to the first rocker arm 2.1.
• control valve 7 could be opened after passing through the swivel passage, generated by the control cam 4.1, so that the swivel movement generated by the auxiliary cam 4.2 and / or the auxiliary cam 4.3 only by the second one Rocker arm 2.2 is executed and the first rocker arm 2.1 remains unactuated.
• the control cam 4.1 and the auxiliary cams 4.2, 4.3 according to FIG. 2 are arranged on a cam track, i.e. together they form a cam.
• the stroke movement generated by the cam or the plunger 11 is transmitted via the second rocker arm 2.2 and the actuating piston 5 to the first rocker arm 2.1 and thus to the cylinder valve 3.2.
• the actuating piston 5 arranged within the pressure medium cylinder 9 bears against the stop surface 5.2 of the first rocker arm 2.1 and takes it along when the control valve 7 is closed.
• the control line 6 is at least partially arranged within the rocker arm shaft 2 and leads from this to the control valve 7 or to the check valve 8.
• the basic diagram of the power flow between the individual drive elements shown in FIG. 3 shows the control cam 4.1, the auxiliary cams 4.2, 4.3, the first rocker arm 2.1, the second rocker arm 2.2, the actuating piston 5 and the cylinder valves 3.1, 3.2.
• the connecting lines shown between the individual drive elements represent the form-fit connections that can be realized.
• the control cam 4.1 and the auxiliary cams 4.2, 4.3 are in direct contact with the second rocker arm 2.2.
• the second rocker arm 2.2 is in operative contact with the pressure medium cylinder 9 and the pressure medium cylinder 9 via the actuating piston 5 with the first rocker arm 2.1.
• the first rocker arm 2.1 in turn is in direct contact with the cylinder valves 3.1, 3.2 or in frictional engagement.
• control cam 4.1 is directly with the first rocker arm 2.1 and this with the Cylinder valves 3.1, 3.2 in operative contact. Only the auxiliary cams 4.2, 4.3 are in operative contact with the cylinder valves 3.1, 3.2 via the second rocker arm 2.2, the pressure medium cylinder 9, the control piston 5 and the first rocker arm 2.1.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Valve Device For Special Equipments (AREA)

Priority Applications (4)

Applications Claiming Priority (2)

Related Child Applications (1)

Publications (1)

Family

ID=32695032

Family Applications (1)

Country Status (5)

Families Citing this family (7)

Citations (3)

Family Cites Families (13)

• 2003
  • 2003-01-30 DE DE10303567A patent/DE10303567A1/de not_active Withdrawn
  • 2003-12-04 WO PCT/EP2003/013687 patent/WO2004067923A1/de not_active Ceased
  • 2003-12-04 EP EP03780118A patent/EP1588027B1/de not_active Expired - Lifetime
  • 2003-12-04 DE DE50313053T patent/DE50313053D1/de not_active Expired - Lifetime
  • 2003-12-04 JP JP2004567300A patent/JP4672372B2/ja not_active Expired - Fee Related
• 2005
  • 2005-07-25 US US11/188,303 patent/US7182054B2/en not_active Expired - Fee Related

Patent Citations (3)

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