EP2891774A1 - Direkt wirkender ventilheber für einen verbrennungsmotor - Google Patents

Direkt wirkender ventilheber für einen verbrennungsmotor Download PDF

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Publication number
EP2891774A1
EP2891774A1 EP12883659.0A EP12883659A EP2891774A1 EP 2891774 A1 EP2891774 A1 EP 2891774A1 EP 12883659 A EP12883659 A EP 12883659A EP 2891774 A1 EP2891774 A1 EP 2891774A1
Authority
EP
European Patent Office
Prior art keywords
cam
valve lifter
sliding contact
contact surface
lifter
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP12883659.0A
Other languages
English (en)
French (fr)
Other versions
EP2891774A4 (de
Inventor
Makoto YASUIKE
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Nittan Corp
Original Assignee
Nittan Valve Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Nittan Valve Co Ltd filed Critical Nittan Valve Co Ltd
Publication of EP2891774A1 publication Critical patent/EP2891774A1/de
Publication of EP2891774A4 publication Critical patent/EP2891774A4/de
Withdrawn legal-status Critical Current

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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
    • F01L1/12—Transmitting gear between valve drive and valve
    • F01L1/14—Tappets; Push rods
    • F01L1/143—Tappets; Push rods for use with overhead camshafts
    • 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
    • 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
    • F01L1/047—Camshafts
    • F01L1/053—Camshafts overhead type
    • F01L1/0532—Camshafts overhead type the cams being directly in contact with the driven valve
    • 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
    • F01L2307/00—Preventing the rotation of tappets

Definitions

  • the present invention relates to a cylindrical direct-action valve lifter of an internal combustion engine incorporated in a valve train of the internal combustion engine.
  • the present invention particularly relates to a valve lifter with a variable lift mechanism.
  • This type of the valve lifter is configured to enable an amount of lift to be altered between a high valve lift and a low valve lift by switching operation of a cam unit integrating a high lift cam and a low lift cam between its high lifter with a high lift cam sliding contact surface and its low lifter with a low lift cam sliding contact surface.
  • a cam unit integrating a high lift cam and a low lift cam between its high lifter with a high lift cam sliding contact surface and its low lifter with a low lift cam sliding contact surface.
  • valve lifter with a variable lift mechanism having the above configuration has to be deployed at a predetermined angle with respect to the cam unit.
  • a second reason is to prevent an oil feeding passage from deviating in position.
  • a cam switching mechanism of the valve lifter is operated by feeding hydraulic pressure from the side of the engine and if the valve lifter rotates and the direction thereof changes, the position of the oil feeding opening on the engine side and that of the oil receiving port on the valve lifter side deviate from each other, whereby the feeding of oil is hindered and the cam switching mechanism acts up.
  • valve lifter needs to be deployed at a predetermined angle with respect to the cam unit, in other words, the valve lifter is required to have directionality relative to the cam unit.
  • these needs are satisfied by providing a detent means in the valve lifter.
  • a pin 102 is projected from the side surface of the valve lifter 101 so as to engage with a longitudinal groove 104 formed on the inner surface of a cylinder bore 103.
  • the pin 102 and the longitudinal groove 104 constitute a detent means of the valve lifter 101.
  • the reference numeral 105 in Figure 14 designates a center lifter which advances and retracts with hydraulic pressure of an oil passage 106 and when the center lifter is located in a retracted position as shown in Figure 14 , a high lift center cam 108 passes through a slit 107 and a low lift cam 109 comes into slidable contact with a low lifter 110. As a result, a valve 111 is opened and closed with low lift.
  • the center lifter 105 advances into the slit 107 and locates at an advanced position thereof, the high lift center cam 108 comes into slidable contact with the outer surface of the center lifter and the valve 110 is opened and closed with high lift.
  • valve lifter with a variable lift mechanism the same technical advantages can be obtained as those in Figure 11 by, contrary to the lifter shown in Figure 14 , providing the pin 102 on the side of a bore and providing the longitudinal groove 104 on the side of the valve lifter. In either case, the detent of the valve lifter can be accomplished by engaging the pin with the longitudinal groove.
  • the conventional detent means requires too much processing such as the forming of the longitudinal groove, the attachment of the pin and the like, and the detent means is not only troublesome to manufacture the detent means but also complicating in configuration. Therefore, the detent means is inevitably abraded away and degraded in durability. Thus, the conventional detent means gives arise troubles such as the occurrence of a strange sound.
  • the problem to be solved by the present invention is to achieve the desirable directionality of the valve lifter with a variable lift mechanism without complicating the structure of the valve lifter.
  • the cam sliding contact surface with which a high lift cam and a low lift cam come into slidable contact is formed to be a smooth inclined surface and a position of the sliding contact surface at which the cam initially comes into contact is disposed lower than a position of the sliding contact surface at which the cam ceases to be in contact, thereby establishing an elevation difference between these points.
  • both a high lift cam and a low lift cam slide uphill on an inclined cam sliding contact surface, namely, from a lower region of the sliding contact surface with which the cam initially comes into contact toward a higher region of the sliding contact surface at which the cam ceases to be in contact.
  • the detent can be realized by simply machining the cam sliding contact surface into an inclined surface, thereby reducing the number of components and the weight of the valve lifter. Further, since it is unnecessary to form a longitudinal groove for preventing rotation on the side of the cylinder bore, processing cost can be reduced. Excellent technical advantages such as simplicity of assembling components, ease of fabricating the valve lifter, and enhanced reliability of the valve lifter thanks to elimination of the risk of abrasion and occurrence of a strange sound.
  • the reference numeral 11 designates a cylinder head of an automobile engine and the reference numeral 12 designates an intake port.
  • the reference numerals 13, 14, 15 and 16 designate an intake valve, a valve stem, a valve lifter with a variable lift mechanism and a cam, respectively.
  • the reference numeral 16a designates a high lift cam and the reference numeral 16b designates a low lift cam.
  • the high lift cam 16a and the low lift cam 16b are integrated with a cam shaft 17 for unitization.
  • the reference numeral 18 designates a cylinder bore and the intake port 12 is closed by pressing the intake valve 13 against the intake port 12 using a coil spring 19 provided in the cylinder bore 18.
  • the cam 16 (16a or 16b) is constituted so as to press the valve lifter 15 downward in Figure 1 against the spring force of the coil spring 19, thereby opening the intake valve 13.
  • the reference numeral 20 designates a cam sliding contact surface of the valve lifter 15. The cam 16 slides on the cam sliding contact surface 20 to push the valve lifter 15, thereby opening the intake valve 13. This operation is repeated so that the valve lifter 15 linearly reciprocates in the cylinder bore 18.
  • the cam sliding contact surface 20 of the valve lifter 15 is provided with a high lifter 15a having a high lift cam sliding contact surface 20a and low lifters 15b, 15b having low lift cam sliding contact surfaces 20b, 20b (See Figures 2 to 5 ). These are disposed in such a manner that the high lifter 15a is sandwiched between the low lifters 15b, 15b from either side.
  • a hydraulic pressure pin 21 laterally penetrating the high lifter 15a is moved by hydraulic pressure, the leading end portion of the hydraulic pressure pin 21 is inserted into the low lifter 15b (See Figure 4 ), whereby the high lifter 15a and the right-and-left low lifters 15b, 15b are integrated (See Figure 5 ).
  • the high lift cam 16a is in contact with the high lift cam sliding contact surface 20a, it does not push down the valve lifter 15, in other words, it makes a blank shot.
  • the low lift cam 16b comes into contact with the low lift cam sliding contact surface 20b and pushes down the valve lifter 15 so that the valve lifter 15 operates to produce a low lift.
  • the high lifter 15a is integrated with the low lifter 15b and the high lift cam 16a comes into contact with the high lift cam sliding contact surface 20a to push down the valve lifter 15.
  • the valve lifter 15 operates to produce a high lift.
  • the reference numeral 22 designates an opening for receiving oil for generating hydraulic pressure
  • the reference numeral 23 designates an operating pin for pushing the hydraulic pressure pin 21
  • the reference numeral 24 designates a return spring for returning the high lifter 20a to its initial position (the position where the high lift cam sliding contact surface 20a and the low lift cam sliding contact surface 20b are located at the same level).
  • the cam sliding contact surface 20 (the high lift cam sliding contact surface 20a and/or the low lift cam sliding contact surface 20b) according to the present invention is configured as a smooth inclined surface.
  • the cam 16 (the high lift cam 16a or the low lift cam 16b) first comes into point contact with a high position H offset from the center of the cam sliding contact surface 20.
  • this position H to be a cam slide starting point A
  • the cam 16 slides on the cam sliding contact surface 20 from point A in accordance with the rotation of the cam 16 and the cam 16 until it leaves the cam sliding contact surface 20 at cam slide terminating point B (See Figure 7 ).
  • the valve lifter 15 rotates owing to the friction resistance of the cam 16 in a direction from point A toward point B, namely, the direction (clockwise direction) indicated by an arrow in Figure 7 .
  • valve lifter 15 receives clockwise torque from the cam 16.
  • the direction of the friction resistance of the cam 16 from point A toward point B bisects the center line of the valve lifter 15 and no rotational force is any longer applied to the valve lifter 15, whereby the rotation of the valve lifter 15 stops.
  • the cam sliding contact surface 20 is configured as an inclined surface, the cam slide starting point arrives at the low position L of the cam sliding contact surface 20 and the rotation of the valve lifter 15 stops, irrespective of the rotational direction of the cam 16.
  • the inclined surface of the cam sliding contact surface 20 is not limited to a flat surface (See Figure 11 ).
  • the inclined surface of the cam sliding contact surface 20 may be configured as a crowned shape (See Figure 9 ) or as a reverse crowned shape (See Figure 10 ). In short, it is sufficient for the cam slide starting point to be lower than the cam slide terminating point, whereby an elevation difference is present between the cam slide starting point and the cam slide terminating point.
  • the cam sliding contact surface 20 is formed so that the left half thereof with respect to the center thereof is formed as a horizontal plane 25 and the right half thereof is formed as a declivitous plane 26.
  • the border between the horizontal plane 25 and the declivitous plane 26 is continuously connected by a smooth curved plane so that the cam sliding contact surface 20 has a crowned shape in which the central portion is high as a whole.
  • Figure 10 shows the cam sliding contact surface 20 having a reverse crowned shape. More specifically, the cam sliding contact surface 20 is formed so that the right half thereof with respect to the center thereof is formed as a declivitous plane 27 and the left half thereof is formed as a horizontal plane 28. The border between the declivitous plane 27 and the horizontal plane 28 is continuously connected by a smooth curved plane so that the cam sliding contact surface 20 has a reverse crowned shape in which the central portion is low as a whole.
  • the cam slide starting point becomes lower than the cam slide terminating point B.
  • the outer diameter of the valve lifter 15 is equal to 30 mm, it is necessary for the elevation difference to exceed 15 ⁇ m and it is preferable for the elevation difference to be equal to or larger than 30 ⁇ m.
  • valve lifters with a variable lift mechanism which are different in arrangement relationship between the high lifter having the high cam sliding contact surface and the low lifter having the low cam sliding contact surface.
  • Figure 12 shows an example in which a low lifter 30 is disposed inside of an annular high lifter 29 and Figure 13 shows an example in which arc-like low lifters 32 are disposed on opposite sides of a rectangular high lifter 31.
  • the cam sliding contact surface according to the present invention incudes these arrangements of the high lifter and the low lifter shown in Figures 12 and 13 .
  • the present invention can be widely applied to a valve lifter with a variable lift mechanism built in an internal combustion engine of, for example, an automobile, industrial vehicle or the like.
  • the reference numeral 11 designates a cylinder head
  • the reference numeral 12 designates an intake port
  • the reference numeral 13 designates an intake valve
  • the reference numeral 14 designates a valve stem
  • the reference numeral 15 designates a valve lifter
  • the reference numeral 16 designates a cam
  • the reference numeral 18 designates a cylinder bore
  • the reference numeral 19 designates a coil spring
  • the reference numeral 20 designates a cam sliding contact surface
  • the reference symbol A designates a cam slide starting point on the cam sliding contact surface
  • the reference symbol B designates a cam slide terminating point on the cam sliding contact surface, respectively.

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)
  • Transmission Devices (AREA)
EP12883659.0A 2012-08-31 2012-08-31 Direkt wirkender ventilheber für einen verbrennungsmotor Withdrawn EP2891774A4 (de)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/JP2012/072158 WO2014033910A1 (ja) 2012-08-31 2012-08-31 内燃機関の直動型バルブリフタ

Publications (2)

Publication Number Publication Date
EP2891774A1 true EP2891774A1 (de) 2015-07-08
EP2891774A4 EP2891774A4 (de) 2016-07-20

Family

ID=50182757

Family Applications (1)

Application Number Title Priority Date Filing Date
EP12883659.0A Withdrawn EP2891774A4 (de) 2012-08-31 2012-08-31 Direkt wirkender ventilheber für einen verbrennungsmotor

Country Status (5)

Country Link
EP (1) EP2891774A4 (de)
JP (1) JP5817040B2 (de)
KR (1) KR101528274B1 (de)
CN (1) CN104603407B (de)
WO (1) WO2014033910A1 (de)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9657606B2 (en) 2015-02-25 2017-05-23 Nittan Valve Co., Ltd. Direct-acting valve lifter of internal combustion engine
USRE47823E1 (en) * 2012-08-31 2020-01-21 Nittan Valve Co., Ltd. Direct-acting valve lifter of internal combustion engine

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6136724Y2 (de) * 1979-09-28 1986-10-24
GB8431407D0 (en) * 1984-12-12 1985-01-23 Stidworthy F M Variable valves
JP3106704B2 (ja) * 1992-07-03 2000-11-06 トヨタ自動車株式会社 内燃機関の動弁装置
JP3933288B2 (ja) * 1998-02-13 2007-06-20 株式会社日立製作所 内燃機関の可変動弁装置
JP3785634B2 (ja) * 2000-08-11 2006-06-14 マツダ株式会社 エンジンの動弁装置
DE10135175A1 (de) * 2001-07-19 2003-02-06 Ina Schaeffler Kg Schaltbarer Tassenstößel
JP4829562B2 (ja) 2005-08-01 2011-12-07 日鍛バルブ株式会社 内燃機関用直動型バルブリフタ
JP2008133770A (ja) * 2006-11-28 2008-06-12 Toyota Motor Corp 可変動弁装置
KR101090798B1 (ko) * 2009-06-04 2011-12-08 현대자동차주식회사 가변 태핏

Also Published As

Publication number Publication date
WO2014033910A1 (ja) 2014-03-06
CN104603407A (zh) 2015-05-06
JP5817040B2 (ja) 2015-11-18
CN104603407B (zh) 2016-04-20
JPWO2014033910A1 (ja) 2016-08-08
EP2891774A4 (de) 2016-07-20
KR20150038655A (ko) 2015-04-08
KR101528274B1 (ko) 2015-06-11

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