KR100309831B1 - VVT device using phase adjustment of 1/2 reduction gear - Google Patents

Abstract

The present invention relates to a VVT (Variable Valve Timing) device for use in an internal combustion engine of a vehicle, and in particular, a phase of a 1/2 reduction gear connecting a cam shaft and a crankshaft by applying a cam gear and a connecting rod whose length is adjusted. The present invention relates to a VVT apparatus using the phase of the 1/2 reduction gear for continuously changing the opening and closing timing of the valve.

It consists of a crank gear that is assembled to the crankshaft to transmit rotational force, a cam gear that is assembled to the camshaft to transfer the driving force from the crankshaft to the camshaft, and an upper part (cam side) and a lower part (crankshaft). It is possible to move up and down, and there is a bevel gear at the end of both parts, and the connecting rod which transmits the rotational force, and the rotating table supported by the bearing so as to be rotatable based on the camshaft center line to support / mount the cam connecting gear and the swivel 2 And a mechanism for supporting the connecting rod, which is connected to the rotating table 1 and the connecting rod with bearings, and which can be rotated based on the center of the rotating table 1, and the rotating rod 1 mounted on the rotating table 1 to receive the rotational force of the connecting rod through the cam gear. Cam connecting gear transmitted to the cam gear side through Appearance is a device for adjusting the rotation angle of the swivel 1 is generally composed of a hydraulic solenoid valve includes a control unit (operation unit) is operated by intermittent hydraulic on / off in response to the ECU signal.

According to the present invention configured as described above, by adjusting the phase of the 1/2 reduction gear connecting the camshaft and the crankshaft by applying the cam gear and the connecting rod whose length is adjusted, the valve opening and closing time can be changed continuously. have.

Description

VVT device using phase control of 1/2 reduction gear

The present invention relates to a VVT (Variable Valve Timing) device for use in an internal combustion engine of a vehicle, and in particular, a phase of a 1/2 reduction gear connecting a cam shaft and a crankshaft by applying a cam gear and a connecting rod whose length is adjusted. The present invention relates to a VVT apparatus using the phase of the 1/2 reduction gear for continuously changing the opening and closing timing of the valve.

In order to operate an internal combustion engine in an ideal state when using an internal combustion engine as a general power source, the internal combustion engine must be adjusted to meet changing external conditions.

The most important factor in this case is the valve timing.

Internal combustion engines mounted in conventional vehicles have a very wide operating range from low speed to high speed and low to high load.

In practice, however, the valve opening and closing timing that makes the engine's intake and exhaust efficiency most ideal is not constant for several rotational regions.

This is because the intake conditions are varied in various operating regions such as inertia of intake gas and resonance with the intake port.

Therefore, the VVT device is very important as a core device for the internal combustion engine.

Conventional vehicle VVT device is a system using a hydraulic pressure, it is necessary to form a separate flow path for driving the VVT system, for example, a cylinder block or a cylinder head, and when several components are engaged by a timing belt or a chain, the power is transmitted. Maintenance of tension has been a problem.

In addition, the internal structure of the parts became complicated and the manufacturability and precision required that the unit price be quite expensive.

In addition, the long development period of parts has been a problem.

Accordingly, an object of the present invention is to solve the problems of the prior art as described above, adjusting the phase of the 1/2 reduction gear connecting the camshaft and the crankshaft by applying the bevel gear and the connecting rod is adjustable in length It is, therefore, to provide a VVT device which continuously changes the opening and closing timing of the valve.

An object of the present invention as described above is a crank gear for assembling the crankshaft to transmit the rotational force, a cam gear for assembling the camshaft to transfer the driving force from the crankshaft to the camshaft, the upper (cam side) and the lower (crankshaft) ) It consists of parts so that the two parts can move up and down, and there is a bevel gear at the end of both parts, and it is supported by a connecting rod that transmits rotational force and a bearing that can be rotated based on the cam shaft center line. Swivel 1 supporting / mounting 2, a swivel 2 that is connected to the swivel 1 and the connecting rod side as a mechanism for supporting the connecting rod, which can be rotated based on the center of the rotating table 1, and the rotating force of the connecting rod mounted on the rotating table 1 The cam connecting gear which receives the through the cam gear to the cam gear side through the crank gear, and the rotation of the rotary table 1 It is a device that adjusts the rotation angle of swivel 1 as shown by the change angle of valve opening / closing time. Generally, a hydraulic solenoid valve is configured to include a control unit that operates by intercepting hydraulic pressure on / off in response to an ECU signal. It is achieved by the VVT device using the phase adjustment of the 1/2 reduction gear.

1 is a perspective view showing a conventional VVT apparatus using hydraulic pressure

Figure 2a is a plan view showing a VVT device using the phase of the 1/2 reduction gear according to the present invention

Figure 2b is a conceptual diagram showing a VVT device using the phase of the 1/2 reduction gear according to the present invention

2c, 2d, and 2e are conceptual views showing the phase change of the camshaft of the VVT device using the phase of the 1/2 reduction gear according to the present invention.

Figure 2f is a conceptual diagram showing the relationship between the cam shaft and the crank shaft and the shaft of the coupling gear of the VVT device using the phase of the 1/2 reduction gear according to the present invention

3A is an explanatory view of operation of a solenoid valve on

3B is an explanatory view of operation when the solenoid valve is off;

4 is an explanatory view of the operation of the rotating table 1.

<Explanation of symbols for main parts of drawing>

1: camshaft 2: cam gear

3: Cam connection gear 4: Swivel 1

5: Swivel 2 6: Connecting rod (gear)

7: crank gear 8: crankshaft

9: crank angle sensor 10: VVT

11: cam angle sensor 12: cam signal plate

13: solenoid valve 14,17: piston

15: Spring 16: Bypass

18: oil supply furnace

With reference to the accompanying drawings, a VVT device using the phase control of the 1/2 reduction gear according to the present invention as described above will be described in detail.

As shown in Figure 2a, the VVT device according to the present invention is a cam shaft (1), cam gear (2), cam coupling gear (3), rotary table 1 (4), rotary table 2 (5), connecting rod (6) And a crank gear 7 and a crank shaft 8.

The cam gear 2 is assembled to the cam shaft 1 to transfer the driving force from the crank shaft 8 to the cam shaft 1, the crank gear 7 is assembled to the crank shaft 8 to the rotational force Will be delivered.

The connecting rod 6 is composed of an upper part (cam side) and a lower part (crank side) to allow two parts to move up and down, and bevel gears at the ends of both parts to transmit rotational force.

The rotating table 1 (4) is supported by a bearing rotatably based on the centerline of the cam shaft (1), and supports / mounts the cam connecting gear (3) and the rotating table (2).

The rotating table 2 (5) is a mechanism for supporting the connecting rod 6 is connected to the rotating table 1 (4) and the connecting rod (6) by the bearing is rotatable based on the center of the rotating table 1 (4).

The cam connecting gear 3 is mounted on the swivel 1 (4) and receives the rotational force of the connecting rod 6 and receives it through the cam gear 2 and transmits it to the cam shaft 1 side.

The control device is a device for controlling the rotation angle of the swivel 1 (4) as the rotation angle of the swivel 1 (4) is represented by the change angle of the belt opening and closing, the general hydraulic solenoid valve 13 receives the hydraulic signal by the ECU It works by interrupting on / off.

In order to describe the present invention in more detail, reference is made to FIGS. 2B to 2D.

As shown in FIG. 2B, the connection gear for phase adjustment rotates around the cam shaft.

If the angle of rotation is α and the angle of the crankshaft is β, the phase change of the camshaft is 3 / 2α-β for the phase change Ψ (α) of the camshaft relative to the phase change α of the connecting gear. Occurs.

The phase change of the camshaft immediately delays or pulls the valve opening and closing time, and this value is also 3 / 2α-β.

Here, α and β are dependent on each other, and since the main variable is α, β can be expressed as a function of α.

If the distance between the camshaft and the crankshaft is H and the distance between the camshaft and the connecting gear shaft is d (= R + r), β can be expressed as follows.

Here, β is positive when α is positive, and β is negative when α is negative, so 3 / 2α-β is a monotonically increasing function of α.

The specific slope value will change depending on the H and d values, but the relationship between α and β is almost linear in the range where α is not large.

This is a very desirable feature and can be applied to the relationship between alpha and beta in a first straight line with respect to the amount of change in valve timing required in actual application.

If the H / d value is larger than 2, the relationship between α and β becomes almost linear, and as the value increases, linearity is ensured in a wider region of α.

If H / d> 2 and α is within ± 15 °, the approximate value Ψ '(α) can be found as a linear function of Ψ (α).

2C induces a phase change Ψ (α) of the camshaft.

FIG. 2D shows that the camshaft and the connecting gear are rotated by α relative to the camshaft together with α in the camshaft.

2E shows that when the connecting gear is rotated about -α to be parallel to the vertical axis y again, the camshaft rotates by 1 / 2α again because the gear ratio with the camshaft is 2: 1. Becomes 3 / 2α.

Figure 2f shows the relationship with the crankshaft. If the crankshaft is rotated by β with respect to the crankshaft while the crankshaft is fixed, the phase of the coupling gear will rotate by -2β with respect to the vertical axis y.

Finally, we want to see the phase change φ (α) of the cam shaft with respect to the phase change α of the connecting gear.

Since the phase change of -2β causes the cam shaft to rotate by β, the phase change Ψ (α) of the cam shaft is finally 3 / 2α-β.

2D is for analyzing the relationship between α and β.

If the distance between the camshaft and the crankshaft is H, the radius of the camshaft is R and the radius of the coupling gear is r, as shown in FIG. 2D, the distance between the camshaft and the coupling gear is d (= R + r). A constant relationship is formed between α, β, H, and d, and thus β can be expressed as a function of α, H, and d.

The length of the line perpendicular to the axis y of the connecting gear is called h and can be solved as follows by the basic definition of the trigonometric function.

Here, β exhibits a linear characteristic of 2% or less with respect to α when H / d is greater than 2 and α is within ± 15 °.

That is, close to the primary straight line passing through the origin.

This linear characteristic becomes larger as H / d becomes larger and α becomes smaller, which is very useful for the analysis and fabrication of the device.

This linearity was obtained by practical graph plotting, rather than mathematical development, and the limits of H / d 2 and the range ± 15 ° of α were considered as values that could almost encompass practical design and operational possibilities. .

Based on the linearity inferred through practical graph plotting, the slope m can be obtained by mathematical development.

The characteristic of the error is 2% when H / d is 2 and α is about 9%, and decreases to 0.5% or less when H / d is 3 or more.

For α, the error is greatest near 9 ° and decreases toward 0 ° and 15 °.

This is because the straight line connecting the origin and the end point (value at 15 °) is obtained, so that the slope can be regained so that the error is the smallest if the range of phase change actually required is more accurately obtained later.

That is, as shown above, a value that minimizes the error among the intermediate values without using the end point can be found by mathematical expansion.

3a and 3b show the operation of the solenoid valve.

When the solenoid valve is turned on in response to a signal from the ECU, the solenoid valve side piston 17 moves backward, the oil supply passage 18 is opened, and the solenoid valve side piston 17 moves by the supplied oil to move the bypass 16. Will be blocked.

At the same time, the supplied oil pushes the booster side piston 14 to rotate the VVT rotating table 1 (4) connected with the booster.

On the contrary, when the solenoid valve is turned off in response to a signal from the ECU, the solenoid valve side piston 17 moves forward to block the oil supply passage 18, open the bypass 16, and the booster side piston 14 springs 15. Rewind by the force of) and rotate the VVT rotating table 1 (4) to its original position.

At this time, the oil has a groove or a hole through which the oil passes in the solenoid valve side piston 17 and is discharged toward the bypass 16 through this hole.

Figure 4 shows the operation of the swivel 1, the swivel 1 is operated in accordance with the operation of the solenoid valve is interlocked with the cam connecting gear and accordingly the connecting rod is slid up and down to the piston movement and the length is variable.

VVT device according to the present invention can transmit the driving force to the cam by the connecting rod connecting the crank and the cam without using the timing belt or chain used in the conventional VVT device, it is simpler than the components required for the conventional VVT device As a result, the product manufacturing process is simplified and is considerably easier to work with, thereby reducing the cost.

Claims (4)

In the VVT apparatus used for the internal combustion engine, A crank gear that is assembled to the crankshaft to transmit rotational force, A cam gear which is assembled to the cam shaft and transmits the driving force from the crank shaft to the cam shaft, A connecting rod which is composed of upper (cam side) and lower (crank side) parts so that the two parts can move up and down, and a bevel gear is provided at the ends of both parts to transmit rotational force, Swivel 1, which is supported by a bearing so as to be rotatable about the camshaft center line, and supports / mounts the cam connecting gear and the swivel table 2, As a mechanism for supporting the connecting rod, the rotating table 2 is connected to the rotating table 1 and the connecting rod side with a bearing, and the rotating table 2 can be rotated based on the center of the rotating table 1. A cam connecting gear mounted on the rotating table 1 to receive the rotational force of the connecting rod through the cam gear and to transmit it to the cam gear through the crank gear; As the rotation angle of the swivel 1 is shown as the change angle of the valve opening and closing time, it is a device that adjusts the rotation angle of the swivel 1. Generally, the hydraulic solenoid valve is operated by controlling the oil pressure on / off by receiving the ECU's signal. VVT device using the phase control of the 1/2 reduction gear, characterized in that configured to include. 2. The VVT device using the phase control of the 1/2 reduction connecting gear according to claim 1, wherein the power transmission between the crank shaft and the cam shaft is performed by a cam connecting gear and a connecting rod without using a timing belt or a chain. The coupling gear for reducing gear according to claim 1 or 2, wherein the connecting rod has a cam side bevel gear and a crank side bevel gear, and is variable in length by vertical piston movement to transmit rotational force. VVT device using phase control. 2. The VVT apparatus according to claim 1, wherein the rotating table 1 is rotatably connected to a piston on the booster side according to the operation of the solenoid valve.