KR19990005569U - Variable valve timing structure - Google Patents

Abstract

The present invention allows the camshaft to be moved horizontally at the same time as the camshaft is rotated at a constant angle by the flyweight whose centrifugal force acts according to the rotational speed of the camshaft sprocket. As a variable valve timing structure of a simple structure that can be converted continuously, in order to achieve the above object, the present invention provides a valve drive for opening and closing the valve by the cam shaft in conjunction with the cam shaft sprocket rotated by the crank shaft In the structure, the sprocket shaft 30 is integrally protruded from the center of the cam shaft sprocket (10), and the circumferential end surface has a helical gear (31); One end is integrally formed on the cam shaft 20 to form an annular guide groove 41 on the outer circumferential surface, and an insertion hole 42 having a helical gear 43 formed on the inner circumferential surface while opening one side of the center of the other end surface. A control block 40 formed with a gear shaft to which the sprocket shaft 30 is coupled; A plurality of support brackets 50 having one end attached to an outer circumference of the cam shaft sprocket 10 and the other end of which is located outward of an outer circumferential surface of the control block 40; A flyweight 61 is formed at one end while being pivotally supported at an end of the support bracket 50, and the other end is a link 60 inserted into the guide groove 41 of the control block 40. It is characterized by the configuration to be made as.

Description

Variable valve timing structure

The present invention relates to a variable valve timing structure of a vehicle, and in particular, a variable valve timing structure to maintain optimum valve timing by allowing the cam shaft phase angle conversion of the vehicle to be continuously performed according to the engine driving state. It is about.

The variable valve timing mechanism refers to maintaining the optimum output according to the operating conditions of the engine by accelerating and decelerating the rotational force of the camshaft according to the engine speed to adjust the opening and closing operation timing of the valve. That is, the valve operation timing is adjusted by allowing the phase angle of the camshaft which cooperates with the crankshaft to be converted.

More specifically, as shown in FIG. 2, the shaft gear 111 having the helical gear is pinned to the outer peripheral surface of the end of the cam shaft 110, and the inner peripheral surface of the shaft gear 111 is fixed to the pin. The plunger 130 having helical gears formed on the outer circumferential surface is rotated, and the hub gear 121 of the cam shaft sprocket 120 is geared to the outer circumferential surface of the plunger 130 by hydraulic pressure. In general, the plunger 130 is horizontally moved so that the phase angle of the cam shaft is instantaneously converted.

In the above structure, the horizontal movement of the plunger 130 is made by adjusting the supply pressure of the oil separating the high speed and the low speed by the solenoid valve 150 controlled by the electronic control device 140.

However, since the valve timing structure as described above forms hydraulic pressure by only the high speed and the low speed by the electronic control device 150 as described above, the valve timing structure does not effectively obtain the valve timing appropriate to the operating conditions, that is, the engine speed and the load condition. In addition, as the installation cost is excessively required due to a complicated configuration such as an oil and an oil supply intermittent structure, there is a problem in that it is difficult to install other than an expensive medium-sized passenger vehicle.

The present invention has been devised to correct the above problems, the present invention is a camshaft horizontal movement at the same time a slight angle by the flyweight that the axial rotation angle changes while the centrifugal force acts according to the rotational speed of the cam shaft sprocket It is a main object to provide a variable valve timing structure with a simple structure such that the phase angle of the camshaft can be continuously converted in accordance with the change of engine driving speed.

In addition, the present invention has another object to improve the engine output while maintaining the optimum valve timing by the continuous phase angle change according to the engine speed and load.

The present invention as a means for achieving the above object

In the valve drive structure which opens and closes a valve by the cam shaft interlocking with the cam shaft sprocket rotated by a crank shaft,

A sprocket shaft integrally protruded from a center of the cam shaft sprocket and having a helical gear formed at an outer circumferential surface of the end surface;

One end is integrally formed on the cam shaft, and the outer circumferential surface is provided with an annular guide groove, and one side of the other end surface is opened while an inner circumferential surface is formed with an insertion hole formed with a helical gear so that the sprocket shaft is gear-coupled. A block;

A plurality of support brackets having one end attached to an outer circumference of the cam shaft sprocket, and the other end of which is located outward of an outer circumferential surface of the control block;

A flyweight is formed at one end while being pivotally supported by the end of the support bracket, and the other end is configured as a link inserted into the guide groove of the control block.

1 is a cross-sectional structural view of the main part according to the present invention

Figure 2 is a half-section structural diagram showing the operating state of the present invention

Figure 3 is a conventional variable valve timing cross-sectional structure diagram

※ Explanation of the code for the main part of the drawing

10: Cam shaft sprocket

20: camshaft

30: Sprocket Shaft

31: helical gear

40: Control block

41: guide groove

42: insertion hole

50: support bracket

60: link

61: fly weight

This will be described in more detail with reference to the accompanying drawings.

Figure 1 is a schematic side cross-sectional structural view showing an embodiment structure according to the present invention, the reference numeral 10 is a cam shaft sprocket (cam shaft sprocket), 20 is a cam shaft.

The camshaft sprocket 10 is a power transmission means connected to the crankshaft and the belt or the chain to make one revolution in two revolutions of the crankshaft. In particular, the sprocket shaft having the helical gear 31 formed on the outer circumferential end of the rear end is formed. The 30 is integrally formed.

The power transmitted by the cam shaft sprocket 10 is interlocked with the cam shaft 20 integrally formed with the cam, which is a valve driving means. A control block 40 is formed with a cross-sectional diameter larger than that of the shaft 20. The control block 40 has an annular guide groove 41 recessed to an outer circumferential surface and an insertion hole 42 having a helical gear 43 formed on the inner circumferential surface thereof while being opened to an end surface of the sprocket shaft 30. do.

In particular, the helical gear 43 formed in the insertion hole 42 is formed by inserting the end of the helical gear 31 of the sprocket shaft 30 into the insertion hole 42. Most preferably, the camshaft 20 has a shape that is geared in the same direction as the axis driving direction so that the cam shaft 20 can interlock.

In addition, one end is attached to the cam shaft sprocket 10 at the outer periphery of the cam shaft 10 side, and the other end has a plurality of support brackets 50 having two or more to be positioned outside the outer periphery of the control block 40. To form.

The control block 40 side end of the support bracket 50 is configured to allow the link 60 to be axially rotatable, and one end of the link 60 is a fly weight 61, which is a weight body. To be formed, the other end is to be inserted into the annular guide groove 41 concave to the outer circumferential surface of the control block 40 to be inserted to a sufficient depth to prevent the departure.

Looking at the operation according to the above configuration as shown in Figure 2 first cam shaft sprocket 10 is the end of the cam shaft 20, the end of which the helical gear 31 of the sprocket shaft 30 integrally protruded in the center is formed One end of the link 60 screwed into the insertion hole 42 of the control block 40 integrally formed in the support block 50 and formed on the support bracket 50 formed at the outer periphery of the camshaft sprocket 10; It is to be inserted into the guide groove (41) concave to the outer peripheral surface of the control block (40). In this case, since the flyweight 61 is formed at the other end of the link 60, one end of the link 50 inserted into the guide groove 41 always controls the control block 40 by the weight of the flyweight 61. Push the cam shaft 20 is in close contact with the sprocket shaft 30 is to act.

When the cam shaft sprocket 10 is rotated by the driving of the crank shaft in this state, the driving force is transmitted to the cam shaft 20 via the sprocket shaft 30 and the control block 40, and at this time, the support bracket 50 The flyweight 61 formed at the outer end of the link 60, which is built up in the crankshaft, rotates the link 60 while being gradually pushed outward by the centrifugal force, and thus the guide groove 41 concave to the outer circumferential surface of the control block 40. The inner end of the link 60 inserted into the control block 40 to push the control block 40 in the direction of the arrow in the figure.

When the control block 40 is horizontally moved by the link 60 in the direction of the arrow, the control block 40 geared with the sprocket shaft 30 moves horizontally and rotates by a predetermined angle from the sprocket shaft 30 at the same time. Will be

That is, when the horizontal movement from the sprocket shaft 30, the control block 40 in the helical gear 31 is rotated by the helical gear 43 of the inner peripheral surface of the insertion hole 42 in addition to the horizontal movement, and eventually the cam The shaft 20 is changed in phase angle by a predetermined angle.

In particular, the above action causes the horizontal movement distance and the rotation angle of the cam shaft 20 to be changed at the same time as the engine speed changes, while the flyweight 61 gradually increases in centrifugal force as the rotation speed of the cam shaft sprocket 10 increases. As it grows, it moves in a direction perpendicular to the axial fixation point of the link 60. As a result, the other end of the link 60 moves the control block 40 by the distance that the flyweight 61 moves. When the speed increases, the horizontal movement distance and phase angle conversion of the camshaft 20 increases, and conversely, when the engine rotation speed decreases, the horizontal movement distance and the phase angle conversion width decrease.

On the other hand, when the cam shaft 20 is gradually rotated at a certain angle simultaneously with the horizontal movement, when the engine speed is gradually decreased to less than the predetermined speed, the cam shaft 20 is in close contact with the sprocket shaft 30 by the weight of the flyweight 61. Will return to the initial state.

As described above, when the cam shaft sprocket 10 and the cam shaft 20 are separated from each other by gear coupling, the horizontal movement distance and the phase angle conversion of the cam shaft 20 are not disconnected according to the increase or decrease of the engine speed. It can be carried out continuously without the appropriate engine control according to the engine driving state.

Therefore, the present invention greatly simplifies the structure, shortens the manufacturing process and lowers the cost, further reducing the economic burden of manufacturing and purchasing the vehicle, and at the same time continuously performing the phase angle conversion of the camshaft. It provides a very useful effect that improves control and driving comfort.

Claims (2)

In the valve drive structure which opens and closes a valve by the cam shaft interlocking with the cam shaft sprocket rotated by a crank shaft, A sprocket shaft 30 integrally protruded from the center of the cam shaft sprocket 10 and having a helical gear 31 formed on an outer circumferential surface of the end surface; One end is integrally formed on the cam shaft 20 to form an annular guide groove 41 on the outer circumferential surface, and an insertion hole 42 having a helical gear 43 formed on the inner circumferential surface while opening one side of the center of the other end surface. A control block 40 formed with a gear shaft to which the sprocket shaft 30 is coupled; A plurality of support brackets 50 having one end attached to an outer circumference of the cam shaft sprocket 10 and the other end of which is located outward of an outer circumferential surface of the control block 40; A flyweight 61 is formed at one end while being pivotally supported at an end of the support bracket 50, and the other end is a link 60 inserted into the guide groove 41 of the control block 40. ; The variable valve timing structure characterized by the structure comprised as follows. The method of claim 1, Variable valve timing, characterized in that the helical gears 31 and 43 for connecting the sprocket shaft 30 and the control block 40 so as to be interlocked are geared in the same direction as the driving direction of the cam shaft sprocket. rescue.