CONTINUOUS VARIABLE VALVE LIFT APPARATUS
A continuous variable valve lift apparatus may include a camshaft, a first cam disposed on the camshaft, an actuating shaft parallel to the cam shaft, an actuating lever connected to the actuating shaft, a swing arm rotatably coupled to the actuating lever and an engine, a second cam pivotally connected to the swing arm and contacting the first cam to open a valve unit and a control portion which is connected to the actuating shaft and selectively rotates the actuating shaft for pivoting center of the swing arm to move.
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The present application claims priority of Korean Patent Application Number 10-2010-0120915 filed in the Korean Intellectual Property Office on Nov. 30, 2010, the entire contents of which application is incorporated herein for all purposes by this reference.
BACKGROUND OF INVENTION1. Field of Invention
The present invention relates to a valve lift apparatus. More particularly, the present invention relates to a continuous variable valve lift apparatus which may adjust valve lift.
2. Description of Related Art
An internal combustion engine generates power by burning fuel in a combustion chamber in air media drawn into the chamber. Intake valves are operated by a cam shaft in order to intake the air, and the air is drawn into the combustion chamber while the intake valves are open. In addition, exhaust valves are operated by the cam shaft, and a combustion gas is exhausted from the combustion chamber while the exhaust valves are open.
An optimal operation of the intake valves and the exhaust valves depends on a rotation speed of the engine. That is, an optimal lift or optimal opening/closing timing of the valves depends on the rotation speed of the engine. In order to achieve such an optimal valve operation depending on the rotation speed of the engine, various researches, such as designing a plurality of cam and a variable valve lift (VVL) that can change valve lift according to engine speed, have been undertaken.
However, a conventional variable valve lift apparatus requires a lot of elements and manufacturing cost is high. And also, friction between each element is considerable and dynamic load is high and thus engine efficiency is deteriorated.
The information disclosed in this Background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.
SUMMARY OF INVENTIONVarious aspects of the present invention have been made in an effort to provide a continuous variable valve lift apparatus having advantages of continuously varying valve lift with simple scheme and small total elements, and reducing manufacturing cost. As such, friction between each element may be reduced, dynamic load may be reduced, and reproducibility may be enhanced.
An exemplary continuous variable valve lift apparatus according to the present invention may include a camshaft, a first cam disposed on the camshaft, an actuating shaft parallel to the camshaft, an actuating lever connected to the actuating shaft, a swing arm rotatably coupled to the actuating lever and an engine, a second cam pivotally connected to the swing arm and contacting the first cam to open a valve unit and a control portion which is connected to the actuating shaft and selectively rotates the actuating shaft to move the pivoting center of the swing arm.
A swing arm shaft may be disposed to the swing arm and the second cam may pivot around the swing arm shaft. A sliding portion may be formed on the actuating lever and the swing arm may be connected to the actuating lever via a control pin which is inserted into the sliding portion and slides along the sliding portion.
The sliding portion may be formed as an ellipse shape or other shapes such that one end of the sliding potion is closer to the actuating shaft than the other end.
A connecting pin may penetrate the actuating shaft and the actuating lever for connecting the actuating shaft and the actuating lever, and a snap ring may be connected to an end of the connecting pin for the connecting pin not to be separated therefrom.
The second cam may include a contact portion contacting the first cam, and a driving portion opening the valve unit. A contact portion roller may be disposed to the contact portion.
The control portion may include a worm wheel disposed to the actuating shaft, a worm gear engaged with the worm wheel and a control motor driving the worm gear.
Another exemplary continuous variable valve lift apparatus according to an exemplary embodiment of the present invention may include a cam shaft, a first cam disposed on the camshaft, an actuating shaft parallel to the camshaft, an actuating lever connected to the actuating shaft, a swing arm rotatably coupled to the actuating lever and an engine, a swing arm shaft disposed to the swing arm. a second cam pivotally connected to the swing arm and contacting the first cam to open a valve unit and a control portion which is connected to the actuating shaft and selectively rotates the actuating shaft for pivoting center of the swing arm to move.
A sliding portion may be formed on the actuating lever and the swing arm may be connected to the actuating lever via a control pin which is inserted into the sliding portion and slides along the sliding portion.
The sliding portion may be formed as an ellipse shape or other shapes such that one end of the sliding potion is closer to the actuating shaft than the other end.
A connecting pin may penetrate the actuating shaft and the actuating lever for connecting the actuating shaft and the actuating lever, and a snap ring may be connected to an end of the connecting pin for the connecting pin not to be separated therefrom.
The second cam may include a contact portion contacting the first cam, and a driving portion opening the valve unit. A contact portion roller may be disposed to the contact portion.
The control portion may include a worm wheel disposed to the actuating shaft, a worm gear engaged with the worm wheel and a control motor driving the worm gear.
The continuous variable valve lift apparatus according to exemplary embodiments of the present invention may continuously vary valve lift with simple scheme and small total number of elements, and reducing manufacturing cost. As such, friction between each element may be reduced, dynamic load may be reduced, and reproducibility may be enhanced.
The methods and apparatuses of the present invention have other features and advantages which will be apparent from or are set forth in more detail in the accompanying drawings, which are incorporated herein, and the following Detailed Description, which together serve to explain certain principles of the present invention.
Reference will now be made in detail to various embodiments of the present invention(s), examples of which are illustrated in the accompanying drawings and described below. While the invention(s) will be described in conjunction with exemplary embodiments, it will be understood that present description is not intended to limit the invention(s) to those exemplary embodiments. On the contrary, the invention(s) is/are intended to cover not only the exemplary embodiments, but also various alternatives, modifications, equivalents and other embodiments, which may be included within the spirit and scope of the invention as defined by the appended claims.
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Hereinafter, the operations of exemplary continuously variable valve lift apparatuses of the present invention will be described with the accompaning drawings
When low lift is required according to engine operation condition, an engine control unit (ECU) controls the control motor 76 so that the actuating shaft 30 rotates in the anticlockwise direction as shown in
And then, the actuating lever 40 connected to the actuating shaft 30 also rotates anticlockwise direction, and the control pin 54 moves along the sliding portion 42. The sliding portion 42 is formed as an ellipse shape or other shapes for the swing arm 50 to rotate around the connecting portion 56. And thus, the swing arm 50 rotates to anticlockwise direction around the connecting portion 56 according to the rotation of the actuating lever 40.
Pivotally connected to the swing arm 50, the second cam 60 rotates along with the swing arm 50. As such, the relative contact position between the driving portion 64 and the valve unit roller 102 changes as in
When high valve lift is required, the actuating shaft 30 rotates to clockwise direction and also the swing arm 50 rotates to clockwise direction as shown in
Although only operations of the high and low lift modes are described, the continuous variable valve lift of the present invention may realize continuous valve lift changes corresponding to the relative conatcting positions.
The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teachings. The exemplary embodiments were chosen and described in order to explain certain principles of the invention and their practical application, to thereby enable others skilled in the art to make and utilize various exemplary embodiments of the present invention, as well as various alternatives and modifications thereof. It is intended that the scope of the invention be defined by the Claims appended hereto and their equivalents.
Claims
1. A continuous variable valve lift apparatus for a vehicle engine comprising:
- a camshaft;
- a first cam disposed on the camshaft;
- an actuating shaft parallel to the camshaft;
- an actuating lever connected to the actuating shaft;
- a swing arm rotatably coupled to the actuating lever and pivotally mounted within a cylinder head of the engine;
- a second cam pivotally connected to the swing arm and contacting the first cam to open a valve unit; and
- a control portion which is connected to the actuating shaft and selectively rotates the actuating shaft to move a pivoting center of the swing arm.
2. The continuous variable valve lift apparatus of claim 1, wherein:
- a swing arm shaft is disposed to the swing arm; and
- the second cam pivots around the swing arm shaft.
3. The continuous variable valve lift apparatus of claim 1, wherein:
- a sliding portion is formed on the actuating lever; and
- the swing arm is connected to the actuating lever via a control pin which is inserted into the sliding portion and slides along the sliding portion.
4. The continuous variable valve lift apparatus of claim 3, wherein the sliding portion is formed in a shape such that one end of the sliding potion is closer to the actuating shaft than the other end thereof.
5. The continuous variable valve lift apparatus of claim 4, wherein the sliding portion is formed as an ellipse shape.
6. The continuous variable valve lift apparatus of claim 3, wherein:
- a connecting pin penetrates the actuating shaft and the actuating lever for connecting the actuating shaft and the actuating lever; and
- a snap ring is connected to an end of the connecting pin for the connecting pin not to be separated therefrom.
7. The continuous variable valve lift apparatus of claim 1, wherein the second cam comprises:
- a contact portion contacting the first cam; and
- a driving portion opening the valve unit.
8. The continuous variable valve lift apparatus of claim 7, wherein a contact portion roller is disposed to the contact portion.
9. The continuous variable valve lift apparatus of claim 1, wherein the control portion comprises:
- a worm wheel disposed to the actuating shaft;
- a worm gear engaged with the worm wheel; and
- a control motor driving the worm gear.
10. A continuous variable valve lift apparatus for a vehicle engine comprising:
- a cam shaft;
- a first cam disposed on the camshaft;
- an actuating shaft parallel to the cam shaft;
- an actuating lever connected to the actuating shaft;
- a swing arm rotatably coupled to the actuating lever and pivotally mounted within a cylinder head of the engine;
- a swing arm shaft disposed to the swing arm;
- a second cam pivotally connected to the swing arm and contacting the first cam to open a valve unit; and
- a control portion which is connected to the actuating shaft and selectively rotates the actuating shaft to move a pivoting center of the swing arm.
11. The continuous variable valve lift apparatus of claim 10, wherein:
- a sliding portion is formed on the actuating lever; and
- the swing arm is connected to the actuating lever via a control pin which is inserted into the sliding portion and slides along the sliding portion.
12. The continuous variable valve lift apparatus of claim 11, wherein the sliding portion is formed in a shape such that one end of the sliding potion is closer to the actuating shaft than the other end thereof.
13. The continuous variable valve lift apparatus of claim 12, wherein the sliding portion is formed as an ellipse shape.
14. The continuous variable valve lift apparatus of claim 10, wherein:
- a connecting pin penetrates the actuating shaft and the actuating lever for connecting the actuating shaft and the actuating lever; and
- a snap ring is connected to an end of the connecting pin for the connecting pin not to be separated therefrom.
15. The continuous variable valve lift apparatus of claim 10, wherein the second cam comprises:
- a contact portion contacting the first cam; and
- a driving portion opening the valve unit.
16. The continuous variable valve lift apparatus of claim 15, wherein a contact portion roller is disposed to the contact portion.
17. The continuous variable valve lift apparatus of claim 10, wherein the control portion comprises:
- a worm wheel disposed to the actuating shaft;
- a worm gear engaged with the worm wheel; and
- a control motor driving the worm gear.
Type: Application
Filed: Aug 23, 2011
Publication Date: May 31, 2012
Applicants: Kia Motors Corporation (Seoul), Hyundai Motor Company (Seoul)
Inventors: Tae Hoon Roh (Seoul), Jong Won Lee (Gunpo-city)
Application Number: 13/215,805