KR20020052315A - vibration reduction device of cam shaft for vehicle - Google Patents

Abstract

PURPOSE: A vibration reducing apparatus of a cam shaft for a vehicle is provided to reduce the driving noise of an engine by suppressing the vibration from axial distortion of the cam shaft with a dynamic damper. CONSTITUTION: A vibration reducing apparatus of a cam shaft of a vehicle is composed of an accelerating sensor(20) integrally engaged with the cam shaft to measure the acceleration of the distortional vibration of the cam shaft(10), an ECU(30) for calculating the distortional vibration frequency transmitted from the acceleration sensor(20) with a spring coefficient and damping value and generating a voltage according to a calculated value, and a dynamic damper(40) installed at the peripheral surface of the cam shaft(10) engaged with the acceleration sensor(20) and decreasing the distortional vibration of the cam shaft(10) by using the voltage transmitted from the ECU(30).

Description

Vibration reduction device of cam shaft for vehicle

The present invention relates to a vibration reduction device of an automotive camshaft, and more particularly, to a vibration reduction device of an automotive camshaft which is capable of reducing the vibration noise of an engine by suppressing the torsional vibration of the camshaft as much as possible.

In general, the cam shaft is disposed on the side or top of the crankcase in parallel with the crankshaft and installed to support the bearing. The camshaft has a cam and fuel pump for opening and closing the intake / exhaust valve. Eccentric cam to drive the helical gear to drive the distributor or oil pump is attached.

These camshafts are connected to each other via a crankshaft and a chain, and are configured to accurately open and close the intake / exhaust valve in accordance with the rotation of the crankshaft.

However, the conventional camshaft generates torsional vibration in the axial direction when the engine is driven, and the torsional vibration not only causes excessive driving noise of the engine, but also transmits this noise to the room, resulting in worse passenger comfort. As a result, there was a problem that the merchandise is also reduced.

Accordingly, the present invention has been made to solve the above problems, by mounting a dynamic damper using an acceleration sensor and the ER fluid on one side of the camshaft, driving noise of the engine by suppressing the axial torsional vibration of the camshaft as much as possible It is an object of the present invention to provide a vibration reduction device for a camshaft for a vehicle that can prevent excessive occurrence and thereby improve indoor riding comfort while reducing indoor noise.

The present invention for achieving the above object, the acceleration sensor is integrally coupled to one end of the camshaft to measure the torsional vibration acceleration of the camshaft, the torsional vibration frequency transmitted from the acceleration sensor and the spring coefficient and damping value The ECU is configured to generate a voltage corresponding to the calculated value, and is mounted on the outer circumferential surface of the cam shaft to which the acceleration sensor is coupled to reduce the torsional vibration of the cam shaft using the voltage transmitted from the ECU. It is characterized by consisting of a damper.

1 is a front view and a side view for explaining a state in which the vibration reduction device according to the invention mounted on the cam shaft,

2 is a partial cross-sectional view taken along line I-I of FIG. 1;

3 and 4 are graphs showing a state in which vibration of the camshaft is attenuated by the vibration reducing device according to the present invention.

<Description of Symbols for Main Parts of Drawings>

10-Camshaft 11-Cylinder Head

12-Damper Pulley 20-Accelerometer

30-ECU (Electronic Control Unit) 40-Dynamic Damper

41-Case 42-Terminal Member

42a-positive terminal 42b-ground terminal

43-ER fluid

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

1 is a front view and a side view for explaining a state in which the vibration reduction device according to the present invention mounted on the camshaft, Figure 2 is a partial cross-sectional view of the line II of Figure 1, the vibration reduction device of the camshaft according to the present invention Accelerometer 20 is integrally coupled to one end of the camshaft 10 to measure the torsional vibration acceleration of the camshaft 10, and the torsional vibration frequency transmitted from the acceleration sensor 20 is damped with a spring coefficient. ECU 30 (electronic control unit) configured to generate a voltage corresponding to the calculated value while calculating with a value, and is mounted on the outer circumferential surface of the cam shaft 10 to which the acceleration sensor 20 is coupled to the ECU 30 Dynamic damper 40 is configured to attenuate the torsional vibration of the camshaft 10 by using the voltage transmitted from the.

The dynamic damper 40 includes a donut-shaped case 41 which is fitted between the outer circumferential surface of the camshaft 10 and the inner circumferential surface of the damper pulley 12 that connects the cylinder head 11, and the case. A terminal member 42 provided inside the 41 and having a positive terminal 42a and a ground terminal 42b for receiving the voltage transmitted from the ECU 30, and the positive terminal 42a and the ground terminal. It consists of an ER fluid 43 which is filled between 42b and attenuates the torsional vibration of the camshaft 10 while the viscosity is changed by the voltage transmitted from the ECU 30.

On the other hand, the ER fluid 43, called an electroheological fluid (ERF), is a suspension in which finely polarized particles are dispersed in an insulating fluid. Viscous) is a fluid that changes.

Therefore, when the camshaft 10 rotates according to the rotation of the crankshaft (not shown), the camshaft 10 generates torsional vibration in the axial direction, and the acceleration of the torsional vibration is the camshaft ( 10 is measured by the acceleration sensor 20 coupled to the central portion of one end.

The torsional vibration frequency of the camshaft 10 measured by the acceleration sensor 20 is transmitted to the ECU 30, and the ECU 30 has a spring coefficient that can cancel the torsional vibration with respect to the torsional vibration. And while calculating the damping value and generates a voltage corresponding to this calculated value is applied to the positive terminal 42a of the dynamic damper 40.

When the voltage of the ECU 30 is applied to the anode terminal 42a of the dynamic damper 40, the electrical properties of the ER fluid 43 constituting the dynamic damper 40 are changed. As the dynamic characteristics of the dynamic damper 40 are changed, the torsional vibration of the cam shaft 10 is attenuated.

On the other hand, when the maximum torsional vibration frequency of the camshaft 10 calculated by the ECU 30 is a low frequency as shown in FIG. 3, the ECU 30 is the positive terminal 42a of the dynamic damper 40. The damping value of the dynamic damper 40 is set low by imposing a low voltage. On the contrary, when the maximum torsional vibration frequency of the camshaft 10 is a high frequency as shown in FIG. 4, the ECU 30 Imposes a high voltage on the positive terminal 42a of the dynamic damper 40 to set the damping value of the dynamic damper 40 high, thereby effectively attenuating the torsional vibration of the camshaft 10.

In other words, in the operating region of the engine where attenuation is largely required, the voltage applied to the ER fluid 43 is increased to increase the viscosity of the dynamic damper 40, and in the operating region of the engine where the attenuation is required to be small, the ER fluid 43 The torsional vibration of the camshaft 10 can be effectively attenuated by reducing the viscosity of the dynamic damper 40 by reducing the voltage applied to the.

As described above, according to the present invention, an acceleration sensor for measuring the torsional vibration of the camshaft is coupled to one end of the camshaft, and the torsional vibration of the camshaft is attenuated by the voltage applied from the ECU to the outer circumferential surface of the camshaft. It is equipped with a dynamic damper, the axial torsional vibration of the camshaft is suppressed by the dynamic damper as much as possible to reduce the driving noise of the engine, thereby reducing the noise transmitted to the room to improve the passenger comfort This has the effect of improving the commerciality.

Claims (2)

Acceleration sensor 20 integrally coupled to one end of the camshaft 10 to measure the torsional vibration acceleration of the camshaft 10, and the torsional vibration frequency transmitted from the acceleration sensor 20, the spring coefficient and the damping value ECU 30, which is configured to generate a voltage corresponding to the calculated value, and is mounted on the outer circumferential surface of the cam shaft 10 to which the acceleration sensor 20 is coupled to calculate the voltage transmitted from the ECU 30. Vibration reduction device for a camshaft for a vehicle made of a dynamic damper 40 to reduce the torsional vibration of the camshaft 10 by using. The donut-shaped case (41) of claim 1, wherein the dynamic damper (40) is fitted between an outer circumferential surface of the camshaft (10) and an inner circumferential surface of a damper pulley (12) connecting the cylinder head (11). And a terminal member 42 provided inside the case 41 and having a positive terminal 42a and a ground terminal 42b for receiving a voltage transmitted from the ECU 30, and the positive terminal 42a. ) And an ER fluid 43 which is filled between the ground terminal 42b and attenuates the torsional vibration of the camshaft 10 while the viscosity is changed by the voltage transmitted from the ECU 30. Vibration reduction device of automotive camshaft.