CN103850746A - Variable valve lift device based on movable cam - Google Patents

Abstract

The invention discloses a variable valve lift device based on a movable cam, which comprises a movable cam, a valve assembly, a rocker arm, a tappet, a camshaft, and a solenoid valve. The camshaft is inside the movable cam, and the cam The rotation of the shaft drives the active cam to rotate, causing the valve ejector rod to reciprocate, thereby using the lever principle of the rocker arm to compress the valve spring to drive the engine valve. By controlling the electromagnetic valve, the base circle axis of the active cam is relative to the The axis of the camshaft deviates from a certain angle, thereby changing the original distance between the movable cam and the valve ejector rod, and realizing variable valve lift. The variable valve has wide application range, low energy consumption and simple control, which is beneficial to the popularization of variable valve technology in engines.

Description

A Variable Valve Lift Device Based on Active Cam

technical field

The invention relates to an engine variable valve lift device.

Background technique

The internal combustion engine is still the prime mover with the highest thermal efficiency and the largest power per unit volume and unit weight. It is widely used. However, with the gradual shortage of energy in the world and the continuous deterioration of environmental resources, we need internal combustion engines to meet stricter emission regulations. Traditional internal combustion engines use fixed-profile cams to drive valves, which makes the emissions and fuel consumption of internal combustion engines not optimal at all operating points. Therefore, most new internal combustion engines use variable valve technology to control emissions and reduce fuel consumption.

At present, variable valve technology is mainly divided into cam-based variable gas distribution technology and camless gas distribution technology. The former can be further subdivided into cam-based mechanical variable gas distribution technology and cam-based electro-hydraulic variable gas distribution technology. The movement is regular, so the structure is relatively simple and the response speed is fast, but because the cam is retained, the valve is only relatively variable and cannot be variable arbitrarily.

In the cam-based electro-hydraulic variable gas distribution technology, part of the valve stroke is provided by the cam, and the other part is changed by hydraulic elasticity. Its characteristics are that the variable degree of the valve is more flexible and the energy consumption is lower. limit.

The camless gas distribution technology can change the valve timing, lift, duration and number of movements arbitrarily. In terms of driving methods, the camless gas distribution technology is divided into electromagnetic drive, electric drive, motor drive, electro-hydraulic drive and other methods. Compared with the disadvantages of high energy consumption of electromagnetic drive, low and unstable response speed of electric drive, and complex motor-driven system, the camless gas distribution technology of electro-hydraulic drive has relatively simple structure and fast response speed. However, it also has unavoidable disadvantages: the flow rate of the hydraulic system is not enough at high speeds, the valve reaches the maximum lift and the seating position is fast, and the impact force is large.

Contents of the invention

Aiming at the above-mentioned prior art, the present invention provides a variable valve lift device based on a movable cam, comprising a movable cam, a valve assembly, a rocker arm, a valve push rod, a camshaft, and a solenoid valve, and the camshaft is arranged radially. There is a pin shaft, and a movable plunger is arranged inside. The movable cam is provided with a guide slot along the axial direction to cooperate with the pin. By controlling the solenoid valve, the movement of the movable plunger is controlled, thereby driving the The movable cam rotates along the pin to change the distance between the movable cam and the tappet to realize any variable valve lift.

In order to solve the above-mentioned technical problems, the present invention provides a variable valve lift device based on a movable cam, including a movable cam, a camshaft, a valve assembly, a rocker arm, a valve push rod, and a solenoid valve, and the rotation of the camshaft drives the movable cam Rotate to make the valve push rod reciprocate, thereby using the lever principle of the rocker arm to compress the valve spring to drive the engine valve. The inside of the movable cam is provided with a long guiding groove along the axial direction, and the movable cam is provided with a long guide groove along the axial direction. There is a long guide hole, and an inverted T-shaped guide groove is provided on the outer contour surface of the movable cam along the direction of rotation; the long guide hole and the guide groove are located at different axial positions on the movable cam. The positions do not overlap; the camshaft passes through the long guide groove, and a radial through hole is arranged in the middle of the camshaft, and a pin shaft is installed in the radial through hole, and at the same time, the two ends of the pin shaft Embedded in the long guide hole; a first plunger hole and a second plunger hole are arranged radially on the outer rotating surface of the camshaft, and a first plunger is arranged in the first plunger hole, The second plunger hole is provided with a second plunger, the inside of the camshaft is provided with an oil inlet and return passage along the axial direction, the first plunger hole is a blind hole, and the bottom of the first plunger is provided with a There is a plunger spring, the first plunger is tightly connected to the plunger spring, the second plunger hole communicates with the oil inlet and outlet passages, and the oil inlet and outlet passages are controlled by a solenoid valve; The tops of the first plunger and the second plunger are in contact with the inner surface of the long guide groove; the valve ejector includes a first ejector and a second ejector, and the first ejector and the second ejector The rods are compressed and connected by a push rod spring, the first push rod and the second push rod move vertically along the engine cylinder wall, the elastic force of the push rod spring is smaller than the preload force of the valve spring, At the same time, the elastic force of the push rod spring is smaller than that of the plunger spring, and the bottom end of the second push rod is hinged with a roller, the outer contour of the roller is inverted T, and the roller is in the guide groove. sports. The invention realizes the rotation of the active cam relative to the camshaft by controlling the solenoid valve, thereby realizing the adjustable valve lift,

Compared with prior art, the beneficial effect of the present invention is:

The invention is a variable valve lift device based on a movable cam, which can be used alone or combined with a timing mechanism to realize a fully variable valve. Promotion on the engine.

Description of drawings

Fig. 1 is the assembly diagram of the variable valve device of the present invention when the valve of the original machine is in a closed state;

Fig. 2 is an assembly drawing of the variable valve device of the present invention when the valve of the original machine is in the state of maximum lift;

Fig. 3 is an assembly drawing of the variable valve device of the present invention in the valve open state when the maximum lift of the valve is increased;

Fig. 4 is an assembly diagram of the variable valve device of the present invention in the closed state of the valve when the maximum lift of the valve is increased;

Fig. 5-1 is the end view of active cam in the present invention;

Figure 5-2 is a left sectional view of the movable cam A-A shown in Figure 5-1;

Fig. 6-1 is the axial view of camshaft among the present invention;

Figure 6-2 is a left sectional view of the cut position of the camshaft B-B shown in Figure 6-1;

Fig. 7 is a front view of the valve push rod in the present invention.

In the picture:

1-Active cam 2-Camshaft 3-Valve assembly 4-Rock arm

5-Valve ejector 6-Solenoid valve 11-Guide long hole 12-Guide groove

13-Guide long groove 21-First plunger 22-Pin shaft 23-Inlet and return oil passage

24-Second plunger 51-First ejector rod 52-Second ejector rod 53-Roller

Detailed ways

The present invention will be further described in detail below in combination with specific embodiments.

As shown in Figures 1 and 2, a variable valve lift device based on an active cam in the present invention includes an active cam 1, a camshaft 2, a valve assembly 3, a rocker arm 4, a valve push rod 5, and a solenoid valve 6, The rotation of the camshaft 2 drives the movable cam 1 to rotate, causing the valve ejector rod 5 to reciprocate, thereby using the lever principle of the rocker arm 4 to compress the valve spring to drive the engine valve, so as to realize the opening and closing of the engine valve.

As shown in Figure 5-1 and Figure 5-2, the inside of the movable cam 1 is provided with a long guiding groove 13 along the axial direction. There is a long guide hole 11, which allows the movable cam 1 to move left and right along the camshaft. The outer contour surface of the movable cam 1 is provided with a circle of inverted T-shaped guide grooves 12 along the direction of rotation. The guide slot 11 and the guide groove 12 are located at different axial positions on the movable cam 1, and the positions of the two do not overlap; as shown in Figure 1, the cam shaft 2 passes through the guide slot 13, as shown in Fig. As shown in Figure 6-1 and Figure 6-2, a radial through hole is provided in the middle of the camshaft 2, and a pin shaft 22 is installed in the radial through hole, and at the same time, the two ends of the pin shaft 22 are embedded in the In the long guide hole 11 ; the movable cam 1 can slide and rotate relative to the pin shaft 22 along the long guide hole 11 .

As shown in Figure 1 and Figure 6-1, a first plunger hole and a second plunger hole are radially provided on the outer rotating surface of the camshaft 2, and a first plunger hole is provided in the first plunger hole. A plunger 21, the second plunger hole is provided with a second plunger 24, the inside of the camshaft 2 is provided with an oil inlet and return passage 23 along the axial direction, and the first plunger hole is a blind hole. The bottom of the first plunger is provided with a plunger spring, the first plunger 21 is tightly connected with the plunger spring, the second plunger hole communicates with the inlet and outlet oil passage 23, and the inlet and outlet The oil channel 23 is controlled by a solenoid valve 6; the tops of the first plunger 21 and the second plunger 24 are in contact with the inner surface of the guide slot 13;

As shown in Figure 7, the valve push rod 5 includes a first push rod 51 and a second push rod 52, and the first push rod 51 and the second push rod 52 are connected by a push rod spring. , the first push rod 51 and the second push rod 52 move vertically along the engine cylinder wall shown in FIG. The elastic force of the push rod spring is smaller than the elastic force of the plunger spring, and the bottom end of the second push rod 52 is hinged with a roller 53, the outer contour of the roller 53 is an inverted T shape, and the roller is positioned in the guide groove 12. inner movement.

The working process of the variable valve lift device of the present invention is as follows:

Fig. 1 and Fig. 2 are the assembly drawings of the variable valve device of the present invention when the valve of the original machine is in the closed state and the maximum lift state of the valve. Return oil first and then close, the movable cam 1 presses the second plunger 24 under the pressure of the first plunger 21, the base circle axis of the movable cam 1 coincides with the axis of the camshaft 2, so The roller at the bottom end of the valve push rod 5 moves along the guide groove 12 of the movable cam 1, thereby realizing valve closing and valve opening.

Fig. 3 is an assembly drawing of the variable valve device of the present invention when the valve maximum lift is increased and the valve is in the open state. At this time, under the control of the electromagnetic valve 6, the oil inlet and outlet passages 23 are closed after the oil is advanced. The first plunger 21 will overcome the force of the second plunger 24 to make the base circle axis of the active cam 1 rotate in the cam direction relative to the axis of the camshaft 2, and at the same time, due to the roller 53 and the active cam 1. The mutual cooperation of the guide grooves 12 will make the movable cam 1 move to the right in the figure, thereby causing the maximum lift of the valve to increase.

Fig. 4 is an assembly diagram of the variable valve device of the present invention in the closed state of the valve when the maximum lift of the valve is increased. On the one hand, the cooperation of the groove 12 makes the movable cam 1 move to the left in the figure relative to the camshaft 2, and on the other hand, the movable cam 1 will pull the second push rod 52 to move downward. When the valve push rod 5 is lower than the position of the valve push rod 5 in Fig. 1, the first push rod 51 will be separated from the second push rod 52 under the action of the push rod spring, thereby eliminating the Effect of maximum lift on valve closed state. Wherein, the spring force between the valve push rods 5 is always smaller than the spring preload force of the valve 3 and the spring force of the first plunger 21, thereby preventing the valve 3 from being pushed open and overcoming the first The spring force of the plunger 21 makes the movable cam 1 rotate.

As mentioned above, the maximum lift of the valve is adjusted by controlling the rotation angle between the base circle axis of the active cam 1 and the axis of the camshaft 2 .

Although the present invention has been described above in conjunction with the drawings, the present invention is not limited to the above-mentioned specific embodiments, and the above-mentioned specific embodiments are only illustrative, rather than restrictive. Under the inspiration, many modifications can be made without departing from the gist of the present invention, and these all belong to the protection of the present invention.

Claims (1)

1. A variable valve lift device based on a movable cam, including a movable cam (1), a camshaft (2), a valve assembly (3), a rocker arm (4), a valve ejector rod (5), a solenoid valve ( 6), the rotation of the camshaft (2) drives the movable cam (1) to rotate, causing the valve ejector rod (5) to reciprocate, thereby using the lever principle of the rocker arm (4) to compress the valve spring to drive the engine valve, It is characterized in that, The inside of the movable cam (1) is provided with a long guiding slot (13) along the axial direction, and the movable cam (1) is provided with a long guiding hole (11) along the axial direction, and the outer surface of the movable cam (1) A circle of inverted T-shaped guide grooves (12) is provided on the contour surface along the direction of rotation; the guide slots (11) and guide grooves (12) are located at different axial positions on the movable cam (1), and both The positions do not overlap; The camshaft (2) passes through the long guide slot (13), and a radial through hole is provided in the middle of the camshaft (2), and a pin shaft (22) is installed in the radial through hole, and at the same time , both ends of the pin shaft (22) are embedded in the guide slot (11); A first plunger hole and a second plunger hole are arranged radially on the outer rotary surface of the camshaft (2), a first plunger (21) is arranged in the first plunger hole, and a first plunger (21) is arranged in the first plunger hole. The second plunger (24) is provided in the second plunger hole, and the interior of the camshaft (2) is provided with an oil inlet and return passage (23) along the axial direction, and the first plunger hole is a blind hole. The bottom of a plunger is provided with a plunger spring, the first plunger (21) is tightly connected to the plunger spring, and the second plunger hole communicates with the oil inlet and return passage (23), so The oil inlet and outlet passage (23) is controlled by a solenoid valve (6); the tops of the first plunger (21) and the second plunger (24) are in contact with the inner surface of the guide slot (13); The valve ejector (5) includes a first ejector (51) and a second ejector (52), and a ejector between the first ejector (51) and the second ejector (52) The spring compression connection, the first ejector rod (51) and the second ejector rod (52) move vertically along the engine cylinder wall, the spring force of the ejector rod spring is smaller than the pre-tightening force of the valve spring, and at the same time , the spring force of the push rod spring is smaller than that of the plunger spring, the bottom end of the second push rod (52) is hinged with a roller (53), the outer contour of the roller (53) is inverted T-shaped, the The rollers move in the guide groove (12).

Images