KR20120038302A - Continuously variable valve timing apparatus - Google Patents

Abstract

PURPOSE: A continuously variable valve timing apparatus is provided to minimize the number of parts by performing motion transmission function of a cycloidal gear with a pin and an eccentric cam. CONSTITUTION: A continuously variable valve timing apparatus includes a housing(350), a cycloid gear device, and a planetary gear device. The cycloid gear device comprises a cycloid external gear(320) and a cycloid internal gear(310). The cycloid external gear device is formed in the inner circumference of the housing. The cycloid inner gear is combined with the cycloid external gear. One or more eccentric cam insertion hole is formed in the outer peripheral part of the cycloid inner gear. The planetary gear device is composed of a ring gear(220), a sun gear(240), one or more planetary gear(250), an eccentric cam(260), a pin(270). The eccentric cam is projected in the planetary gear to the axial direction and is inserted into the eccentric cam insertion hole. The pin is projected from the eccentric cam to the axial direction.

Description

Continuously variable valve timing device {CONTINUOUSLY VARIABLE VALVE TIMING APPARATUS}

The present invention relates to an electronic continuous variable valve timing device, and more particularly, a planetary gear device in which rotational force is controlled by an electromagnetic clutch, and a cycloid gear device connected to the planetary gear device to change the rotational speed of the camshaft in the housing. It relates to a built-in CVVT device.

In general, an internal combustion engine engine is a device that generates power by inhaling air and fuel from the outside and combusting it in a combustion chamber. It is provided with a valve, the intake and exhaust valve is opened and closed in conjunction with the rotation of the cam shaft rotates in conjunction with the rotation of the crankshaft.

However, since the optimum opening and closing time of the intake / exhaust valve may vary according to the engine speed, engine load, etc., the rotation of the camshaft is not determined decisively according to the rotation of the crankshaft. A technology for controlling proper valve timing has been developed and is called Variable Valve Timing (VVT).

Continuously Variable Valve Timing (CVVT) is a type of such variable valve timing, and has a configuration in which the valve timing can be controlled to any value within a set displacement.

However, the conventional electronic CVVT apparatus has a problem that a large space is required when mounting an engine because of its long longitudinal size. That is, when the rotational force generating mechanism is an electronic motor, the length of the motor and the length of the variable device portion are excessive, and when the rotational force generating mechanism is the electromagnetic clutch, the variable device portion is too long, and it is difficult to mount the electronic CVVT in a vehicle with a small engine room. There was a problem.

The present invention has been made to solve the above problems, the planetary gear device and the cycloid gear device is built in the housing connected to the camshaft to provide a more compact structure CVVT device, and the function to make the cycloid gear eccentric movement and Its purpose is to provide a compact electronic CVVT device by minimizing the number of parts because the eccentric cam and the pin formed integrally with the planetary gears transmit the rotating motion of the cycloid gear to the adapter at the same time.

Embodiment according to the present invention for achieving the above object is a continuous variable valve timing (CVVT) device is mounted on the cam shaft to change the valve timing by adjusting the rotation of the cam shaft, the rotation is received from the crankshaft to rotate housing; A cycloid gear device including a cycloid outer gear integrally formed on an inner circumferential surface of the housing, and a cycloid inner gear gear engaged with the cycloid outer gear and having at least one eccentric cam insertion hole formed at an outer circumference thereof; A ring gear, a sun gear, and at least one planetary gear that is gear-coupled to the ring gear and the sun gear respectively between the ring gear and the sun gear, and rotates about its axis, and revolves about the sun gear, protruding axially eccentrically to the planet gear A planetary gear device inserted into the eccentric cam insertion hole and receiving a rotational force from the cycloid inner gear, and a pin projecting axially from the eccentric cam and concentric with the planetary gear; At least one pin insertion hole into which the pin is inserted is formed at an outer circumference thereof and rotates by the revolution of the planetary gear, and is fixed to the cam shaft to transmit the rotational force generated by the revolution of the planetary gear to the cam shaft; And an inner clutch that selectively stops the sun gear and an outer clutch that surrounds the inner clutch and selectively stops the ring gear, and electrons that change the rotational direction of the planetary gear by selectively stopping the ring gear and the sun gear. clutch; It provides a CVVT device comprising a.

Embodiment according to the invention is characterized in that the inner clutch operates at the time of perception, the outer clutch operates at the time of advance.

Embodiment according to the invention is characterized in that the ring gear rotates without being constrained by the rotation of the housing.

An embodiment according to the present invention is characterized in that the eccentric cam rotates the cycloid inner gear in a direction opposite to the relative rotation direction of the eccentric cam, and the pin transfers the rotational motion of the cycloid inner gear to the adapter. .

Embodiment according to the invention is characterized in that the number of the planetary gear is any one of 1 to 3.

Embodiment according to the present invention is characterized in that the planetary gear device and the cycloid gear device is embedded in the housing to have a compact structure.

According to an embodiment of the present invention, the outer friction plate is integrally formed on one side of the ring gear so that the ring gear is selectively rotated by the outer clutch, and the inner friction plate is integrally formed on one side of the sun gear. The sun gear is selectively rotated by the inner clutch.

According to the present invention as described above, the variable control unit is composed of a thin planetary gear device and a cycloid gear device, and the eccentric cam and the pin performs the function of rotating the cycloid gear and transmitting the movement of the cycloid gear to minimize the number of parts and At the same time, there is an effect to manufacture a compact electronic CVVT device.

1 is an exploded perspective view of an electronic CVVT device according to an embodiment of the present invention.
2 is a cross-sectional view of the electronic CVVT device in accordance with an embodiment of the present invention.
3 is a perspective view of a planetary gear and an eccentric cam according to an embodiment of the present invention.
Figure 4 is a front sectional view of the planetary gear and the eccentric cam according to an embodiment of the present invention.
Figure 5 is a side cross-sectional view of the planetary gear and the eccentric cam according to an embodiment of the present invention.
FIG. 6A is a cross-sectional view taken along line AA of FIG. 2, FIG. 6B is a cross-sectional view taken along line BB of FIG. 2, FIG. 6C is a cross-sectional view taken along line CC of FIG. 2, and FIG. DD sectional drawing of 2.
FIG. 7A is a cross-sectional view taken along the line AA of FIG. 2, B is a cross-sectional view taken along the line BB of FIG. 2, and FIG. 7C is a cross-sectional view taken along the line CC of FIG. 2, and FIG. DD sectional drawing of 2.

Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention.

1 and 2, the planetary gear device 200 having the sun gear 240, the ring gear 220 and the planetary gear 250 as its rotating elements, and the current of FIG. Cycloid to change the rotational direction of the input side by receiving rotational power from the disk-shaped electromagnetic clutch 100 and the planetary gear device 200 to selectively stop the sun gear 240 or the ring gear 220 by selective supply. And a housing 350 surrounding the gear device 300 and the camshaft 400. At this time, the output of the planetary gear device 200 is transmitted to the cam shaft 400 through the adapter 330 fixed to the cam shaft 400 by the fastening bolt 500. The electromagnetic clutch is provided with a friction material (not shown).

First, the electronic clutch 100 includes an inner clutch 110 having a hole formed in the center thereof and a disc shaped outer clutch 120 formed on an outer circumferential surface of the inner clutch 110.

In addition, the planetary gear device 200 is integrally with the inner friction plate 230 and the inner friction plate 230 rotated by the operation of the inner clutch 110 in a position corresponding to the inner clutch 110. The sun gear 240 is formed, the outer friction plate 210 is determined to rotate by the operation of the outer clutch 120 in a position corresponding to the outer clutch 120, and the outer friction plate 210 integrally with The ring gear 220 is formed, the planetary gear 250 that revolves and rotates while simultaneously gearing and engaging with the sun gear 240 and the ring gear 220, and extends from the planetary gear 250 to protrude and form the planetary gear. Cylindrical eccentric cam 260 having an eccentric cam shaft 265 that is different from the rotation axis of the gear 250, and a rotation axis further protruding from the eccentric cam 260, the same rotation axis 255 of the planetary gear 250 It consists of a pin 270 having a. The inner circumferential surface of the sun gear 240 is free to rotate without being constrained to the outer circumferential surface of the protrusion 336 of the adapter 330 which will be described later. At this time, the planetary gear 250 rotates around the planetary gear rotation axis 255 and revolves around the sun gear 240.

3 to 5 with respect to the eccentric cam 260 and the pin 270, the pin has the same rotation axis as the planetary gear rotation axis 255, but the eccentric cam 260 is the planetary gear rotation axis ( 255) has a different axis of rotation.

The eccentric cam 260 penetrates through the eccentric cam insertion hole 315 formed in the cycloid inner gear 310, and the pin 270 penetrates through the pin insertion hole 335 formed in the adapter 330. In addition, the adapter 330 is formed with a protrusion 336 so that the inner circumferential surface of the planetary gear 250 can freely rotate on the outer circumferential surface of the adapter protrusion 336.

At this time, one of the planetary gears 250 may be any one, but at least two planetary gears to operate more stably. In particular, it is preferable to have three planetary gears 250. In addition, the outer circumferential surface of the ring gear 220 does not come into contact with the housing 350 so as to be free to rotate with each other.

The cycloid gear device 300 is coupled to the cycloid inner gear 310 and the cycloid inner gear 310 is driven by the rotation of the eccentric cam 260 of the planetary gear device 200 of the housing 350 It consists of a cycloid outer gear 320 formed on the inner peripheral surface. The cycloid gear device 300 is rotated in response to the rotational direction of the eccentric cam 260 while rotating while receiving the driving force from the eccentric cam 260.

Said cycloidal gear is a kind of speed reducer which performs the function of reducing the rotational speed of the output side of a cycloidal gear compared with the rotational speed of an input side, and changing the rotational direction of an output side opposite to the rotational direction of an input side. However, on the contrary, even when rotation power is applied to the output side, the rotation direction of the eccentric cam on the input side cannot be changed. This is because the reduction ratio of the cycloidal gear device is large. That is, in the CVVT apparatus according to the embodiment of the present invention, the cycloid inner gear 310 may be rotated by the eccentric cam 260 in a direction opposite to the rotation direction of the eccentric cam 260, but the cycloid inner gear ( Due to the rotation of 310, the eccentric cam 260 cannot be rotated in the opposite direction to the rotational direction of the cycloid inner gear 310. Details thereof are obvious to those skilled in the art, and thus detailed descriptions thereof will be omitted.

Hereinafter, the planetary gear device 200 and the cycloidal gear device 300 will be referred to as a variable control unit.

In addition, the housing 350 is formed on the outer circumferential surface of the camshaft 400 and the movement in the axial direction is constrained by the camshaft flange 410, and the adapter 330 is connected to the camshaft 400 by the fastening bolt 500. It is fixed.

Hereinafter, an operation process according to the embodiment of the present invention will be described in more detail.

First, the operation process at the time of advance is explained.

As shown in FIG. 6A, the housing 350 always rotates clockwise. The cycloidal inner gear 310 that rotates while being geared with the cycloidal outer gear 320 formed on the inner circumferential surface of the housing 350 also rotates clockwise. The rotational force of the cycloid inner gear 310 is transmitted through the eccentric cam 260 inserted into the eccentric cam insertion hole 315 formed in the outer circumferential portion of the cycloid inner gear 310 to protrude from the eccentric cam 260. Adapter 330 rotates clockwise by 270. At this time, the ring gear 220 and the sun gear 240 geared to the planetary gear 250 is locked (rotated) and rotates clockwise while having the same angular velocity integrally.

As a result, the valve timing is constant because all of the above components are rotated clockwise in the locked state. This is the same also in the late perception described later.

The key is to make the camshaft 400 precede the original rotation direction at the time of the advance angle. The outer clutch 120 operates while the housing 350 rotates clockwise at a constant speed. When the outer clutch 120 operates, the friction material embedded in the outer clutch 120 stops the outer friction plate 210. At the same time, the ring gear 220 which is integrally connected to the outer friction plate 210 is stopped. At this time, the ring gear 220 and the housing 350 are not in contact with each other and are not constrained by the rotation of each other to allow free rotation. Thus, the housing 350 continues to rotate clockwise.

In this case, since the adapter 330 is also rotated in the clockwise direction, the planetary gear 250 revolves clockwise by the pin 270 inserted into the adapter 330. In order to rotate the planetary gear 250 in a clockwise direction while the ring gear 220 is stopped, the planetary gear 250 should rotate in a counterclockwise direction. That is, the eccentric cam 260 is rotated in the counterclockwise direction. This is illustrated in B, C of FIG. 6.

When the eccentric cam 260 rotates counterclockwise and rotates clockwise, the cycloid inner gear 310 driven by the eccentric cam 260 performs eccentric movement of the eccentric cam 260. It rotates in a clockwise direction opposite to the rotating direction. That is, the cycloid inner gear 310 is slightly ahead in the clockwise direction with respect to the housing 350. This is transmitted to the adapter 330 by the pin 270 to rotate the adapter 330 clockwise to advance the camshaft 400 clockwise relative to the housing 350.

As a result, the cam shaft 400 is rotated further in the clockwise direction than usual, resulting in faster valve timing.

Hereinafter, a description will be given of the operation process during the lateness.

Even in late hours, the housing 350 rotates clockwise at normal speed, as shown in FIG. 7A. The cycloid inner gear 310 and the adapter 330 also rotate clockwise, and the planetary gear 250, the sun gear 240 and the ring gear 220 also rotate clockwise at the same angular speed. However, the inner clutch 110 operates as opposed to the advance angle. When the inner clutch 110 is operated, the inner friction plate 230 is stopped by the friction material of the inner clutch 110. When the inner friction plate 230 is stopped, the sun gear 240 which is integrally connected to the inner friction plate 230 is stopped. However, at this time, the housing 350 is rotated in the clockwise direction, and the planetary gear 250 connected to the adapter 330 must also revolve in the clockwise direction, so that the planetary gear 250 is connected to the sun gear 240. Rotate clockwise. That is, as illustrated in B and C of FIG. 7, the eccentric cam 260 connected to the planetary gear 250 rotates clockwise and rotates clockwise.

By the rotation of the eccentric cam 260 in the clockwise direction, the cycloid inner gear 310 is rotated counterclockwise with respect to the housing 350 by the eccentric cam 260.

That is, the pin 270, which is the output side of the cycloid inner gear 310, revolves counterclockwise, and the pin 270 is inserted to transmit the rotational force of the pin 270 to the adapter 330. After being transmitted to 330, the camshaft 400 is transmitted to the camshaft 400 so that the camshaft 400 is rotated counterclockwise than usual, thereby delaying the valve timing.

As described above, the cycloid gear device 300 and the planetary gear device 200 are embedded in the housing 350 to maximize the utilization of the space, and the eccentric cam 260 for the cycloid gear device 300 to perform the eccentric motion is cycloid. It is inserted into the eccentric cam insertion hole 315 formed in the inner gear 310, the pin 270 is inserted into the pin insertion hole 335 of the adapter 330 can make the configuration of the device even thinner.

All of the above operations are possible because the driving force of the crank is transmitted to the housing by the chain, thus eliminating the need for a motor.

In addition, the eccentric cam 260 and the pin (1) integrally connected with the planetary gear 250 to transfer the eccentric motion of the cycloid gear device 300 and the rotating motion of the cycloid gear device 300 to the adapter 330 270), the number of parts can be minimized.

Furthermore, the present invention minimizes the use of current by using an electronic clutch instead of a motor.

100: electromagnetic clutch 110: inner clutch
120: outer clutch 200: planetary gear device
210: outer friction plate 220: ring gear
230: inner friction plate 240: sun gear
250: planetary gear 255: planetary gear rotation axis
260: eccentric cam 265: eccentric cam axis
270: pin 300: cycloidal gear mechanism
310: cycloid inner gear 315: eccentric cam insertion hole
320: cycloid outer gear 330: adapter
335: pin insertion hole 336: adapter protrusion
350: housing 400: camshaft
410: camshaft flange 500: fastening bolt

Claims (7)

In the continuous variable valve timing (CVVT) apparatus mounted on the cam shaft to change the valve timing by adjusting the rotation of the cam shaft,
A housing that receives rotational force from the crankshaft and rotates;
A cycloid gear device including a cycloid outer gear integrally formed on an inner circumferential surface of the housing, and a cycloid inner gear gear engaged with the cycloid outer gear and having at least one eccentric cam insertion hole formed at an outer circumference thereof;
A ring gear, a sun gear, and at least one planetary gear that is gear-coupled to the ring gear and the sun gear respectively between the ring gear and the sun gear, and rotates about its axis, and revolves about the sun gear, protruding axially eccentrically to the planet gear A planetary gear device inserted into the eccentric cam insertion hole and receiving a rotational force from the cycloid inner gear, and a pin projecting axially from the eccentric cam and concentric with the planetary gear;
At least one pin insertion hole into which the pin is inserted is formed at an outer circumference thereof and rotates by the revolution of the planetary gear, and is fixed to the cam shaft to transmit the rotational force generated by the revolution of the planetary gear to the cam shaft; And
An inner clutch that selectively stops the sun gear and an outer clutch that surrounds the inner clutch and selectively stops the ring gear, and an electronic clutch that changes the rotational direction of the planetary gear by selectively stopping the ring gear and the sun gear. ;
CVVT device comprising a. The method of claim 1,
And the inner clutch operates at the time of perception and the outer clutch operates at the time of advance. The method of claim 1,
And the ring gear rotates without being constrained by rotation of the housing. The method of claim 1,
And the eccentric cam rotates the cycloid inner gear in a direction opposite to the relative rotation direction of the eccentric cam, and the pin transmits the rotational motion of the cycloid inner gear to an adapter. The method of claim 1,
CVVT apparatus, characterized in that the number of the planetary gear is any one of 1 to 3. The method of claim 1,
The planetary gear device and the cycloidal gear device is embedded in the housing to have a compact structure CVVT device. The method of claim 1,
An outer friction plate is integrally formed at one side of the ring gear so that the ring gear is selectively rotated by the outer clutch, and an inner friction plate is integrally formed at one side of the sun gear so that the sun gear is formed by the inner clutch. CVVT device, characterized in that rotated selectively.

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