The present application claims the benefit of Korean Patent Application No. 10-2015-0094060, filed Jul. 1, 2015, which is incorporated herein by reference in its entirety.
The present disclosure generally relates to a mechanical valve opening and closing apparatus having a cap and a locker arm that open and close a valve via which air is supplied to a cylinder.
The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Typically, when an engine is operating, both air and fuel are supplied to a combustion chamber of a cylinder. Fuel is injected by an injector, while air is supplied to the combustion chamber through the operation of a cam and a valve provided in the cylinder head. At this time, it is required to adjust a point in time to open the valve, or the amount of the opening of the valve, depending on the operation area of the engine. In the related art, in order to blow air taken in by the cam and the valve into the combustion chamber, the valve disposed on the upper surface of the combustion chamber is opened and closed by the cam using a hydraulic circuit.
The foregoing is intended merely to aid in the understanding of the background of the present disclosure, and is not intended to mean that the foregoing is already known to those skilled in the art.
The present disclosure to provides a valve opening and closing apparatus having a simplified configuration and a superior response rate, and being able to adjust the point in time to open a valve and the amount of the opening of the valve by controlling all of a plurality of locker arms without using a hydraulic mechanism.
According to one aspect of the present disclosure, there is provided a valve opening and closing apparatus including: a plurality of rocker arms each causing a valve to be opened and closed using rotation of a cam through contact with the cam; an eccentricity-creating unit disposed on the rocker arm, wherein the eccentricity-creating unit changes an eccentric position using rotation of a rotary shaft extending through the plurality of rocker arms; and a driving unit connected to the rotary shaft of the eccentricity-creating unit to rotate the rotary shaft.
The driving unit may be coupled to the rotary shaft to control all of the plurality of rocker arms.
The driving unit may include a plurality of gears and a motor.
The eccentricity-creating unit may include: eccentric cams rotatably disposed in a corresponding rocker arm of the plurality of rocker arms; and the rotary shaft eccentrically coupled to the eccentric cams. The eccentric position of the eccentric cams is adjusted following the rotation of the rotary shaft, thereby adjusting a degree to which the cams contact the corresponding rocker arm.
A rotary member may extend through and be coupled to one end portion of the corresponding rocker arm. A pressing part may be provided on the other end portion of the corresponding rocker arm such that the valve is to be pressed by the pressing part.
Each of the plurality of rocker arms may include: a body to which the eccentric cams are coupled; and an actuating part pressing the valve when pressed by the body. The body and the actuating part are coupled to each other by means of the rotary shaft of the actuating unit extending therethrough.
The body may include a front section, a rear section, and a connecting section. The front section and the rear section are symmetrical to each other. Each of the front section and the rear section has a through-hole in a central portion thereof to which a corresponding eccentric cam of the eccentric cams is coupled. Each of the front section and the rear section has a coupling hole in one portion and a pressing portion on the other portion. The pressing portion extends sideways from above the through-hole.
The actuating part may have a rotation hole in one portion thereof, through which the rotary shaft extends, and an extension on the other portion thereof, extending sideways from above the rotation hole. The pressing part is provided on the extension. The extension has support lugs protruding therefrom in a lateral direction.
The body may have through-holes in central portions to which the eccentric cams are coupled, coupling holes in predetermined portions, and pressing portions on the other portions. The actuating part may have a rotation hole in one portion and an extension on the other portion. The pressing part is provided on the extension. The body and the actuating part may be coupled to each other by means of the rotary shaft extending through the rotation hole. The pressing part may press the valve in response to the pressing portions pressing upon support lugs of the extension.
The actuating part may have a bearing on a portion of the actuating part corresponding to the rotary shaft.
Each of the eccentric cams may have a bearing coupled to the outer circumference thereof.
According to the valve opening and closing apparatus as described above and hereinbelow, unlike the related art in which the cam is mainly used to adjust the point in time in which the valve is to be opened and the amount of the opening of the valve, the eccentricity-creating unit having a simple configuration is provided on the rocker arms, such that the point in time in which the valve is to be opened and the amount of the opening of the valve can be precisely controlled depending on the driving areas of the engine. In addition, it is advantageously possible to control the eccentricity of all of the plurality of rocker arms, since the plurality of rocker arms are connected via the single rotary shaft and the rotary shaft is controlled using the driving unit.
In particular, since a hydraulic circuit having a complicated configuration can be omitted, the valve opening and closing apparatus has a simplified configuration and is reduced in weight and the number of components, thereby obtaining the effects of optimized fuel efficiency and reduced costs. In addition, since the valve opening and closing apparatus operates mechanically, the response rate thereof is improved compared to a hydraulic mechanism. Accordingly, the valve opening and closing apparatus has improved performance in low torque due to the improved response rate.
Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.
In order that the disclosure may be well understood, there will now be described various forms thereof, given by way of example, reference being made to the accompanying drawings, in which:
The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way.
The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. Reference will now be made in greater detail to a valve opening and closing apparatus according to an embodiment of the present disclosure, an example of which is illustrated in the accompanying drawings. Wherever possible, the same reference numerals will be used throughout the drawings and the description to refer to the same or like parts.
As illustrated in
The driving unit 900, 910, and 930 are coupled to one end portion of the rotary shaft 500 to control all of the plurality of rocker arms 300, although individual driving units could be used for each rocker arm 300. The driving unit 900, 910, and 930 include a plurality of gears 910 and 930 and a motor 900. When the motor 900 operates, the second gear 930 coupled to the motor 900 rotates. Following the rotation of the second gear 930, the first gear 910 coupled to one end portion of the rotary shaft 900 rotates, thereby adjusting the eccentricity of all of the plurality of rocker arms 300. Even in the case in which a plurality of intake valves or a plurality of exhaust valves are provided on a single cylinder, as in a double overhead camshaft (DOHC), the driving unit 900, 910, and 930 can advantageously adjust the eccentricity of all of the plurality of rocker arms 300 through a single operation thereof.
Although the driving unit 900, 910, and 930 are illustrated as including the motor 900, the first gear 910, and the second gear 930, this is not intended to be limiting. Since such a configuration or arrangement is correlated to the layout, the driving unit can be modified or changed depending on the environment or the design as long as the rotary shaft can be rotated thereby.
In addition, the eccentricity-creating unit 400 and 500 includes eccentric cams 400 and the rotary shaft 500. The eccentric cams 400 are rotatably disposed in the rocker arms 300, and the rotary shaft 500 is rotatably and eccentrically coupled to the eccentric cams 400. With this configuration, the eccentric position 430 (
A rotary member 600 extends through and is coupled to one end portion of each of the rocker arms 300 via a pin 610, and a pressing part 700 is provided on the other end portion of each of the rocker arms 300. The rotary member 600 may be implemented as a roller. A point in time in which the valve 200 is opened and the amount of the opening of the valve 200 are determined by the correlation between the rotary member 600 and the cam 100, i.e. depending on the distance set between the center of the cam 100 and the center of the pin 610, which defines the center of rotation of the rotary member 600.
Therefore, according to the present disclosure, the point in time in which the valve 200 is opened and the amount of the opening of the valve 200 are variably controlled by adjusting the distance in the center between the cam 100 and the pin 610 by changing the eccentric position 430 of cams 400 in response to the rotation of the rotary shaft 500 of the eccentricity-creating unit 400 and 500. Since the pressing part 700 may be integrally formed on the corresponding rocker arm 300, the pressing part 700 may be implemented as a screw or the like. According to the present disclosure, the pressing part 700 is illustrated as including a screw or bolt 710 and a fastening member 730 such that the point in time in which the valve 200 is opened and the amount of the opening of the valve(s) 200 can be more precisely adjusted once again using the pressing part 700. The fastening member 730 is implemented as a nut, such that the screw 710 can be adjusted by the nut 730.
According to the present disclosure, the displacement of the rocker arm 300 is changed by the cam 100 as in a related-art valve opening and closing apparatus. In response to the changed displacement, the rocker arm 300 presses against or releases pressure from the valve 200, such that the valve 200 is opened or closed. Unlike the related-art valve opening and closing apparatus, which mainly uses the cam in order to change a point in time to open or close the valve, according to the present disclosure the rocker arm 300 is provided with the eccentricity-creating unit 400 and 500, such that the point in time in which the valve 200 is opened and the amount of the opening of the valve 200 can be can be mechanically varied using a simple configuration. Since the mechanism allowing the valve 200 to be opened and closed using the cam 100 is well known to a person skilled in the art, a detailed description thereof will be omitted.
In addition, the eccentricity-creating unit 400 and 500 may be provided on a rocker arm having a typical configuration, such that the eccentric position 430 of cams 400 can be adjusted through the rotation of the rotary shaft 500, thereby variably adjusting the point in time in which the valve 200 is opened and the amount of the opening of the valve 200. However, according to the embodiment of the present disclosure, the rocker arm 300 has been illustrated and described as having a body 310 and an actuating part 330.
As illustrated in
As best seen in
In addition, the actuating part 330 has a rotation hole 331 in one portion thereof. The diameter of the rotation hole corresponds to, and is preferably sized larger than, the outer diameter of the rotary shaft 500, such that the rotary shaft 500 extends through the rotation hole 331. Thus, a bearing 337 can be provided in the portion of the rotation hole 331 corresponding to the rotary shaft 500. The bearing 337 enables the rotary shaft 500 to have smooth relative motion within the rotation hole 331. Although the bearing 337 may be omitted when the rotation hole 331 is formed of aluminum (Al), the bearing 337 is preferably used when the rocker arm 300 is formed of a cast iron or a forged iron or steel.
An extension 333 is provided on the other portion of the actuating part 330 (opposite the one portion having the rotation hole 331), extending sideways (or orthogonally) from above the rotation hole 331. The pressing part 700 is provided on the extension 333. The extension 333 has support lugs 335 protruding from the extension 333 in a lateral direction, i.e. from the right and left portions of the extension 333 (e.g. protruding forwardly/rearwardly). In particular, the support lugs 335 are formed in position corresponding to the pressing portions 316 of the body 335. When the pressing portions 316 press the support lugs 335, the actuating part 330 is actuated to press the valve 200. As illustrated in the drawings, the support lugs 335 may be integrally formed on the actuating part 330 by molding, shaping, or the like. Alternatively, the support lugs 335 may be formed separate pieces and subsequently coupled to a hole or recesses (not shown) formed in the rocker arm 300.
When the coupling relationship between the body 310 and the actuating part 330 is described in summary, the front section 311 and the rear section 312 of the body 310 are maintained at a predetermined distance from each other, and the eccentric cams 400 are coupled to the through-holes 314 formed in the front and rear sections 311 and 312. Bearings 410 may be coupled to the outer circumference of the eccentric cams 400 for smooth relative rotation of the eccentric cams 400. The bearings 410 may be needle bearings, which are disposed at predetermined distances along the outer circumference of the eccentric cams 400. On the other hand, like the bearings 337, the bearings 410 of the eccentric cams 400 may be omitted depending on the environment or the design.
After the actuating part 330 is fitted between the front section 311 and the rear section 312, the rotary shaft 500 sequentially extends through and is fitted into the eccentric cam 400 in the front section 331, the rotation hole 331 of the actuating part 330, and the eccentric cam 400 in the rear section 312. Therefore, when the rotary shaft 500 rotates, the eccentric cams 400 rotate, changing the eccentric position 430, whereby the position in which the rocker arm 300 (namely body 310 via rotatory member 600) contacts the cam 100 is changed. Consequently, in the state in which the position in which the rocker arm 300 contacts the cam 100 is changed, the support lugs 335 of the actuating part 330 are pressed by the pressing portions 316 of the body 310, thereby pressing the valve 200. In this manner, the point in time in which the valve 200 is opened and the amount of the opening of the valve 200 can be adjusted.
Although not illustrated in this disclosure, the rotary shaft 500 may be driven by a driving part (not shown) controlled by a controller (not shown). However, a person skilled in the art can make many modifications or alterations to this configuration without departing from the scope of the present disclosure.
An operation in response to eccentric variable control by the valve opening and closing apparatus will be described in greater detail with reference to
Thus, when the angle of timing at which the cam 100 opens and closes the valve 200 is increased as in
When the engine is in a low-speed operation area, the eccentric position 430 is controlled to be in a low-right position (down and right on the page in
As described above, the valve opening and closing apparatus can mechanically vary the eccentric position 430 using the eccentricity-creating unit 400 and 500 having a simple configuration without a complicated configuration, such as a hydraulic circuit. It is therefore possible to set the point in time in which the valve is to be opened and the amount of the opening of the valve according to driving states, based on the cam profiles of the driving areas of the engine, thereby more precisely controlling the engine.
Unlike the related art in which the cam is mainly used to adjust the point in time in which the valve is to be opened and the amount of the opening of the valve, according to the valve opening and closing apparatus as described above, the eccentricity-creating unit having a simple configuration is provided on the rocker arms, such that the point in time in which the valve is to be opened and the amount of the opening of the valve can be precisely controlled depending on the driving areas of the engine. In addition, it is advantageously possible to control the eccentricity of all of the plurality of rocker arms, since the plurality of rocker arms are connected via the single rotary shaft and the rotary shaft is controlled using the driving unit.
In particular, since a hydraulic circuit having a complicated configuration can be omitted, the valve opening and closing apparatus has a simplified configuration and is reduced in the weight and the number of components, thereby obtaining the effects of optimized fuel efficiency and reduced costs. In addition, since the valve opening and closing apparatus operates mechanically, the response rate thereof is improved compared to a hydraulic mechanism. Accordingly, the valve opening and closing apparatus has improved performance in low torque due to the improved response rate.
Although the exemplary embodiments of the present disclosure have been described for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the present disclosure as disclosed in the accompanying claims.
Number | Date | Country | Kind |
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10-2015-0094060 | Jul 2015 | KR | national |