Variable valve actuation mechanism for an internal combustion engine

Inactive Publication Date: 2007-07-19
TOYOTA JIDOSHA KK
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0046] It is preferable that, by creating the difference in the thermal expansion coefficient, the leak down property value of the lash adjuster provided for a cylinder in which the valve actuation value is relatively increased due to a high temperature be set greater than the leak down property of a cylinder in which the valve actuation value is relatively decreased du

Problems solved by technology

Particularly, when the slider gear is moved in a direction for increasing the valve lift, the engaging portion is likely to receive a great force.
Therefore, if the control shaft has an insufficient strength, the engaging portion can be deformed.
Therefore, even if the actuator detects the amount of movement of the control shaft to control the movement amount of the

Method used

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  • Variable valve actuation mechanism for an internal combustion engine
  • Variable valve actuation mechanism for an internal combustion engine
  • Variable valve actuation mechanism for an internal combustion engine

Examples

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Example

[0133] The first embodiment described above has the following advantages.

[0134] (1) In the control shaft 132, the engaging portions 132c are engaged with the slider gears 128 by the control pins 132a, and are made of a high-strength iron based material as described above. The remaining portions of the control shaft 132, that is, the coupler shafts 132d do not need to be as strong as the engaging portions 132c. The coupler shafts 132d are therefore made of an aluminum alloy material like the cylinder head 8. Therefore, compared to a case where the control shaft 132 is entirely made of an iron based material, the thermal expansion coefficient of the control shaft 132 is closer to that of the cylinder head 8. Specifically, the coefficient of linear expansion of an iron based material is approximately 10 to 12×10−6 (1 / ° C.), while the coefficient of linear expansion of an aluminum alloy material is 24 to 25×10−6 (1 / ° C.). Therefore, compared to a case where the control shaft 132 is mad...

Example

Second Embodiment

[0144] A control shaft 232 of the second embodiment has four engaging portions 232c-1 to 232c-4 and four coupler shafts 232d-1 to 232d-4. The coupler shafts 232d-1 to 232d-4 are made of a material having a thermal expansion coefficient that is greater than that of the cylinder head 8. The coupler shafts 232d-1 to 232d-4 are used with the engaging portions 232c-1 to 232c-4, which are made of an iron based material, such that the thermal expansion coefficient of the entire control shaft 232 is substantially equal to that of the cylinder head 8. Control pins 232a-1 to 232a-4 are made of an iron-based material. The other components are the same as those in the first embodiment, and are thus given the same reference numerals as the first embodiment.

[0145] The engaging portions 232c-1 to 232c-4 are made of an iron-based material the linear expansion coefficient of which is represented by a (1 / ° C.). The coupler shafts 232d-1 to 232d-4 are made of an aluminum alloy mater...

Example

Third Embodiment

[0177] In a third embodiment, a control shaft 282 includes a single shaft main body 282d as shown in FIG. 18(A). The shaft main body 282d is made of the same material as that of the cylinder head or of an aluminum alloy material the thermal expansion coefficient is substantially the same as that of the material of the cylinder head.

[0178] As shown in FIG. 18(B), the shaft main body 282d has rectangular holes 282e, the number of which is the same as the number of the cylinders. Each rectangular hole 282e extends in the axial direction. An engaging portion 282c, the shape of which is substantially the same as the rectangular holes 282e, is fitted in each rectangular hole 282e.

[0179] A support hole 282b is formed in each engaging portion 282c. As shown in FIG. 19, the proximal end of a control pin 282a is inserted into and supported by each support hole 282b. The engaging portions 282c and the control pins 282a are both made of a high-strength iron based material.

[0...

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PUM

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Abstract

Engaging portions 132c, each of which is engaged with a slider gear, are made of an iron based material, and coupler shafts 132d are made of an aluminum alloy material that is the same material as that of a cylinder head. Therefore, compared to a case where the control shaft 132 is entirely made of an iron based material, the thermal expansion coefficient of the control shaft 132 is closer to that of the cylinder head. Therefore, even if the ambient temperature changes, the position of each engaging portion 132c relative to the cylinder head is prevented from being displaced. Also, since the engaging portions 132c are made of an iron based material, the engaging portions 132c have a sufficient strength, which prevents the control shaft 132 from being deformed.

Description

[0001] This is a 371 national phase application of PCT / JP2005 / 000949 filed 19 Jan. 2005 claiming priority to Japanese Applications No. 2004-010896 filed 19 Jan. 2004, No. 2004-153936 filed 24 May 2004, and No. 2004-226145 filed 02 Aug. 2004, the contents of which are incorporated herein by reference.FIELD OF THE INVENTION [0002] The present invention relates to a variable valve actuation mechanism for an internal combustion engine that adjusts the actuation of valves by axially moving a control shaft with an actuator in the engine. BACKGROUND OF THE INVENTION [0003] For example, Japanese Laid-Open Patent Publication No. 2001-263015 discloses such a variable valve actuation mechanism. In this mechanism, a control shaft is axially moved with an actuator, so that a slider gear engaged with the control shaft is moved axially. Accordingly, the valve actuation such as the valve duration angle and the valve lift is adjusted. SUMMARY OF THE INVENTION [0004] Since the control shaft of a vari...

Claims

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Application Information

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IPC IPC(8): F01L1/34F01L1/18F01L13/00
CPCF01L1/022F01L1/185F01L1/2405F01L1/267F01L2820/032F01L13/0063F01L2101/00F01L2105/00F01L13/0015F01L2301/00F01L2305/00
Inventor MIYAZATO, YOSHIAKIYOSHIHARA, YUJIHOSODA, FUMINORIKOSHIMIZU, TAKAHIDESHIMIZU, KOICHITATENO, MANABUTANI, MASAAKI
Owner TOYOTA JIDOSHA KK
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