KR20020015825A - An automotive variable valve timing device using planetary gear system - Google Patents

Abstract

PURPOSE: A variable valve timing device for a planetary gear is provided to simplify the structure and make the size of the device small with a gear unit and a motor only for improving the operation response time and continuously and freely setting a valve variable angle. CONSTITUTION: A variable valve timing device for a planetary gear includes an operation element for opening and closing a valve by rotation force received from a crank shaft of an engine via a belt, and a timing element for controlling valve opening and closing time in association with the operation element, wherein the operation element has a ring gear(5) to receive rotation force generated from the crank shaft of the engine, and a carrier(3) coupled with a cam shaft(1) and having a planetary gear(6) contacting the ring gear, and the timing element includes a linear gear(15) fixed to the cam shaft via a fixing shaft(2) and engaged with the planetary gear, a worm wheel(14) engaged with a worm gear(13) formed on a shaft of a step motor(12), of which rotation direction is changed in response to the rotation of the cam shaft, and a rotary encoder(11) for measuring a rotation amount of the worm wheel to generate electric signals.

Description

An automobile variable valve timing device using planetary gear system}

The present invention relates to a variable valve timing apparatus for a vehicle using planetary gears, and more particularly, to a variable valve timing apparatus for a vehicle using planetary gears with quick response and continuous variable angles and free setting of the valve angle.

In general, it is very important that internal combustion engines such as gasoline engines and diesel engines maintain the timing of opening and closing the valve precisely so that the inlet, compression, and discharge of the mixer can be continuously performed through opening and closing of the valve. .

Normally, the opening and closing timing of such a valve does not occur at the top dead center or the bottom dead center of the piston, i.e., in the case of the intake valve, the suction stroke is opened just before the top dead center just before the suction stroke of the piston so that a large amount of the mixer is introduced into the cylinder. It is closed immediately after the bottom dead center.

On the other hand, the exhaust valve is opened immediately before the bottom dead center, just before the exhaust stroke of the piston, so as to completely discharge the exhaust gas, so that the combustion gas is quickly discharged from the combustion chamber and closed immediately after the top dead center immediately after the exhaust stroke. do.

In this way, an overlap occurs at the beginning of the intake stroke from the end of the exhaust stroke, which opens the intake valve and the exhaust valve together to completely discharge the combustion gas and at the same time increase the filling efficiency of the mixer.

Since the optimum condition of the valve opening / closing timing and overlap is not always the same in the entire rotational speed region and the full load region of the internal combustion engine, the valve opening / closing timing is always optimal according to the rotational speed and the size of the load. A variable valve timing device that variably controls this to be maintained in a state is used. Among these variable valve timing devices, Japanese Patent Application Laid-Open No. 60-11115 and Japanese Patent Application Laid-Open No. 62-191632 provide a valve according to the rotational speed and the magnitude of the load of the internal combustion engine. The opening / closing timing of the valves is varied, that is, the opening and closing times of the intake valves and the exhaust valves are adjusted by the hydraulic pressure to reduce or increase the overlap of the valves.

However, such a variable valve timing device is not only complicated to supply the hydraulic pressure supply system for supplying hydraulic pressure but also to find the optimum valve opening / closing timing under actual operating conditions where the rotational speed is substantially changed due to the low transmission speed of the hydraulic pressure. There is a problem of delay time.

Accordingly, the present invention has been made in view of the above, and its purpose is to provide a simple structure and a miniaturization of the gear device and the motor so that the valve variable angle can be set continuously and freely while the operation response is fast.

The present invention for achieving the above object, the operating means for opening and closing the valve by receiving the rotational force from the crankshaft of the engine via the belt, and in conjunction with the operating means to control the opening and closing time of the valve It is composed of a timing means, the operation means is a carrier gear coupled to the cam shaft having a ring gear that receives the rotational force generated from the engine from the crankshaft, and a planetary gear inscribed to the ring gear, the timing The worm wheel is fixed to the camshaft by means of a fixed shaft and is engaged with the planetary gear of the operating means, and a worm wheel engaged with the worm gear provided on the shaft of the step motor whose direction of rotation changes as the camshaft rotates. And a rotary encoder for generating an electrical signal by measuring the amount of rotation of the worm wheel.

1 is a block diagram of a variable valve timing device for a vehicle using a planetary gear according to the present invention

<Description of the symbols for the main parts of the drawings>

1: Camshaft 2: Fixed shaft

3: carrier 4,7,10,16: bearing

5: ring gear 6: planetary gear

8: gear pin 9: carrier cover

11: rotary encoder 12: motor

13: Worm Gear 14: Worm Wheel

15: sun gear

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram of a variable valve timing device for a vehicle using a planetary gear according to the present invention, the present invention is an operating means for opening and closing the valve by receiving a rotational force through the belt from the crank shaft of the engine and A camshaft having a cam for operating the valve of the engine according to a crankshaft for transmitting the rotational force of the engine. ), The timing means adds rotational force in the same or opposite direction to the rotational direction of the camshaft (1).

Here, the operation means is composed of a ring gear (5) receiving the rotational force generated from the engine from the crankshaft, and a carrier (3) inscribed in the ring gear (5) and coupled to the camshaft (1), The carrier 3 is composed of a plurality of planetary gears 6 which are fixed to the carrier cover 9 via the gear pins 8 and inscribed and rotated in the ring gear 5.

In addition, the timing means is fixed to the camshaft (1) via the fixed shaft (2), the sun gear 15 meshed with the planetary gear (6) of the operating means, and one side of the fixed shaft (2) It consists of a control means for rotating the sun gear 15 in a clockwise or counterclockwise direction is fixed to the step motor 12 and the rotational direction thereof changes in accordance with the rotation of the camshaft (1), and A worm wheel 14 provided on one side of the fixed shaft 2 to rotate the fixed shaft 2 fixed to the cam shaft 1 by being engaged with the worm gear 13 provided on the shaft of the step motor 12 and the It consists of a rotary encoder 11 provided on one side of the fixed shaft (2) to generate an electrical signal by measuring the amount of rotation of the worm wheel (14).

On the other hand, between the carrier (3) and the ring gear (5) and the gear pin (8) and the planetary gear (6), which is a rotating part of the operating means, respectively, to reduce friction, ball bearings (4) and needle roller bearings ( On the other hand, the fixed shaft 2 of the timing means includes a worm wheel 14 coupled to the fixed shaft 2 as well as between the fixed shaft 2 and the carrier 3 at the front end of the sun gear 15. Bearings 16 and 10 are provided between the encoders 11, respectively.

Hereinafter, the operation of the present invention will be described in detail.

When power is transmitted from the crankshaft which generates the rotational force according to the operation of the engine to the ring gear 5 of the operating means via the belt, the planetary gear 6 of the carrier 3 inscribed in the ring gear 5 ) Rotates and rotates along the sun gear 15 fixed by the control means of the timing means, whereby the carrier 3 rotates to rotate the camshaft 1 fixed thereto to open the valve. It will be closed.

At this time, the rotational force of the camshaft 1 is decelerated by the operating means and the timing means, which is determined in the following relationship.

Primary deceleration ratio = (Z1 / Z3 + 1) x (T2 / T1)

Where Z1: sun gear completion, Z3: ring gear completion,

T1: Take crankshaft pulley, T2: Take camshaft pulley.

Subsequently, when the motor 12 constituting the control means of the timing means rotates while the cam shaft 1 is rotated, the worm wheel 14 is rotated through the worm gear 13 of the motor 12 and the cam shaft 1 The sun gear 15 is rotated together with the fixed shaft 2 fixed to the shaft. At this time, the opening / closing operation angle of the valve is delayed or accelerated according to the rotation direction of the sun gear 15.

At this time, the change angle of the camshaft 1 and the deceleration according to the rotation of the motor 12 of the timing means are determined in the following relationship.

2nd reduction ratio = (Z3 / Z1 + 1) x (Ng / Nw)

Camshaft change angle = 360 ° / 2 difference reduction ratio

Where Ng is the number of worm wheels and Nw is the number of worm gear leads.

Accordingly, if the sun gear is rotated by a predetermined angle in the rotational direction of the camshaft 1, the rotation of the camshaft 1 is increased by a large amount of the operating angle, while the sun gear is in the opposite direction to the rotational direction of the camshaft 1. If the predetermined angle is rotated, the rotation of the camshaft 1 by the operation angle is delayed.

This will be described by way of example with the following conditions.

That is, crankshaft pulleys (T1) = 25, camshaft pulleys (T2) = 40, ring gears (Z3) = 72, sun gears = 18, worm wheels = 64, worm gear lead = 1 Suppose you are a dog,

First, since the reduction ratio T2 / T1 = 40/25 = 2 / 1.25 of the crankshaft and camshaft pulley, and the reduction ratio Z1 / Z3 = 18/72 + 1 = 1.25 of the sun gear and the ring gear, the first reduction ratio = T2 / T1 x (Z1 / Z3 + 1) = 2 / 1.25 x (1.25) = 2, while the rotation angle change of the camshaft (1) with the rotation of the motor 12 is the reduction ratio of the worm wheel and the worm gear Ng / Nw = 64 Since / 1 = 64, the secondary reduction ratio = (1 / 1.25) x 64 = 320, and as a result, the angle of change of the cam shaft 1 according to one rotation of the motor 12 becomes 360/320 = 1,125 °.

Therefore, the camshaft 1 is added clockwise or counterclockwise by 1,125 degrees according to the one rotation direction of the motor 12, and of course, it may speed up or delay timing of opening and closing of a valve.

In addition, if the operation of the motor 12 is forcibly controlled, the rotation angle of the cam shaft 1 is adjusted to a desired angle, so that the opening / closing timing of the valve can be arbitrarily adjusted.

Here, the encoder 11 is typically used as a reference signal for the control of the reference signal of the controller or the motor 12 by converting the rotational speed to an electrical signal of course.

As described above, according to the present invention, while the camshaft rotated by receiving the rotational force from the crankshaft of the engine via the belt is operated by the motor, the rotational force is changed through the gears engaged with each other, thereby opening and closing timing of the valve. Miniaturization is achieved by a simple structure to control the control panel, and only the gear unit and the motor have an effect of enabling quick and responsive operation of the valve variable angle and setting the valve variable angle continuously.

Claims (6)

It consists of an operation means for opening and closing the valve by receiving the rotational force from the crankshaft of the engine via the belt, and a timing means for adjusting the opening and closing time of the valve in conjunction with the operation means, the operation means is The camshaft 1 including the cam for operating the valve of the engine is rotated according to the crankshaft which transmits the rotational force, and the timing means adds the rotational force in the same or opposite direction to the rotational direction of the camshaft 1. Variable valve timing device for vehicles using planetary gears. 2. The actuating means according to claim 1, wherein the actuating means comprises a ring gear (5) which receives the rotational force generated from the engine from the crankshaft, and a carrier (3) inscribed to the ring gear (5) and coupled to the camshaft (1). The carrier 3 is composed of a plurality of planetary gears 6 which are fixed to the carrier cover 9 via a gear pin 8 and rotated in an inscribed manner to the ring gear 5. Variable valve timing device for vehicles using planetary gears. The method of claim 1, wherein the timing means is fixed to the camshaft (1) via the fixed shaft (2), the sun gear (15) engaged with the planetary gear (6) of the operating means and the fixed shaft ( 2) is fixed to one side of the variable valve timing device for a vehicle using a planetary gear, characterized in that consisting of a control means for rotating the sun gear 15 clockwise or counterclockwise. 4. The control means according to claim 3, wherein the control means comprises: a motor (12) whose rotation direction changes with the rotation of the cam shaft (1), a transmission member for transmitting the rotational force of the motor (12) to the fixed shaft (2); Variable valve timing device for a vehicle using a planetary gear, characterized in that the rotary encoder (11) provided on one side of the fixed shaft (2) to measure the amount of rotation of the transmission member to generate an electrical signal. The worm wheel according to claim 4, wherein the transmission member rotates a worm gear 13 provided on the shaft of the motor 12 and a fixed shaft 2 that is engaged with the worm gear 13 and fixed to the cam shaft 1. 14) Variable valve timing device for a vehicle using a planetary gear, characterized in that consisting of. The method according to any one of claims 2, 3 and 5, wherein between the carrier (3) and the ring gear (5) and the gear pin (8) and the planetary gear (6), which are rotational parts of the actuating means. And between the fixed shaft 2, the carrier 3, the worm wheel 14, and the encoder 11 of the timing means, bearings 4, 7, 10, and 16 are provided. Variable valve timing device for vehicles.