KR20070026941A - Apparatus for variable valve lift follower - Google Patents

Abstract

A variable valve lift follower is provided to improve engine performance and fuel efficiency by sucking air at a high speed in a low velocity range and sucking a large amount of air within a high velocity range. A variable valve lift follower(13) comprises a cam operating unit, an outer body(14), an inner body, a lock operating unit, and a valve contact unit. The cam operating unit has a center with a low lift cam(10) and both sides with high lift cams(11). The outer body has an upper surface with a contact pad(17) contacting the high lift cams. The inner body is assembled to the outer body so that the inner body independently operates. The inner body has a center equipped with a roller(18) contacting the low lift cam. The lock operating unit is mounted on a front end of the inner body so that a lock pin extends/retracts from/into an interior of the lock operating unit. The valve contact unit is formed at a lower end of the lock operating unit.

Description

Apparatus for variable valve lift follower}

1 is a graph showing the opening and closing timing of an intake valve and an exhaust valve.

Figure 2 is a perspective view showing a conventional variable valve lift system.

Figure 3 is a perspective view showing a conventional variable valve lift follower.

4 is a cross-sectional view taken along the line “A-A” of FIG. 3.

5 is a perspective view showing a variable valve lift system according to the present invention.

Figure 6 is a perspective view showing a variable valve lift follower according to the present invention.

7 is a perspective view showing a lock pin according to the present invention.

8A is a cross-sectional view taken along the line “B-B” of FIG. 6, showing an operating state of the variable valve lift follower according to the present invention at a low speed section;

8B is a cross-sectional view taken along the line “B-B” of FIG. 6, showing an operating state of the variable valve lift follower according to the present invention at a high speed section.

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

10: low lift cam 11: high lift cam

12: Camshaft 13: Variable valve lift follow

14: outer body 15: inner body

16: lock operation portion 17: contact pad

18: roller 19: valve contact

20: lock body 20a: oil supply unit

21: lock pin 21a: body

21b: protrusion 22: return spring

23: Hydraulic Lash Adjuster

24: spring seat 25: snap ring

The present invention relates to a variable valve lift follower device, and more particularly, by applying a variable valve lift to an intake valve to increase the intake air speed at a low lift, and to apply a high lift at a full load condition to increase the amount of intake air. A variable valve lift follower device for improving performance and fuel efficiency is provided.

In general, since the rotational speed of the internal combustion engine generally varies from about 500 RPM to 6000 RPM, the flow of air or mixer that is sucked into the engine is greatly changed, and the flow rate of air or mixer and exhaust gas by opening and closing the intake valve and exhaust valve. In the reciprocating internal combustion engine that controls the pressure, it is necessary to increase the charging efficiency by increasing the open time of the intake valve in order to obtain high output at high speed.However, when the open time of the intake valve is increased, the overlap with the exhaust valve is increased. Since the rotational state of the engine becomes poor at low speed operation, the overlap shown in FIG. 1 must be kept within a certain range.

Therefore, a variable valve lift apparatus is used to improve the output performance by matching the opening and closing timing of the intake valve and the exhaust valve to the engine operating conditions.

As shown in FIG. 2, in the swing arm type, one cam is driven by contact with one valve. However, in the variable valve lift system, three cams are applied to one valve.

In addition, the cam of the camshaft is divided into three, the middle cam 10 forms a low lift, and the two cams 11 on both sides form a high lift. At this time, the protrusion of the high lift cam 11 is protruded relatively more than the low lift cam 10.

3 is a perspective view showing the structure of a conventional variable valve lift follower, including an outer body 14 and an inner body 15, a contact pad 17 in contact with the high lift cam 11, and a low lift cam. It consists of the roller 18 which contacts 10.

In this case, the contact pad 17 is integrally formed with the outer body 14, and the roller 18 is integrally formed with the inner body 15.

The variable valve lift follower 100 is independently driven by the outer body 14 and the inner body 15 separated from each other, and the valve is in contact with the roller 18 of the inner body 15. Receives the rotational movement of 10) and moves up and down to operate as a low lift.

More specifically, Figure 4 is a cross-sectional view taken along the line "AA" of Figure 3, the valve contact portion 19 is formed on one side of the lower body of the inner body of the variable valve lift follower 13, the other side is HLA ( Hydraulic Lash Adjuster) 110 is formed.

The HLA 23 is a portion where oil is always supplied, and oil having a constant pressure is introduced into the inner body 15 through the HLA contact portion 210.

The lock plate body 120 and the lock plate 121 are coupled to each other at the right end of the inner body 15, and the lock plate 121 has two rectangular blocks in the transverse direction to the lock plate body 120. The structure is inserted.

In addition, the inner body 15 is provided with a piston 130 at regular intervals from the lock plate 121, and one end surface of the piston 130 and one end surface of the lock plate body 120 are in contact with each other. That is, one end of the lock plate body 120 is coupled to the lock plate 121, and the other end of the lock plate body 120 is in contact with the piston 130.

In this structure, when oil is introduced through the HLA contact portion 210 formed at the bottom of the inner body 15 and filled in the inner body 15, the other end of the lock plate body 120 is pushed by the pressure of the oil, and the piston 130 and the lock plate 121 can be inserted into the rear end of the outer body 14.

When the lock plate 121 is inserted into the lower rear portion of the outer body 14 and the inner body 15 and the outer body 14 are locked, the outer body 15 and the inner body 14 move integrally to the outer body. The low lift cam 10 is turned away from the roller 18 of the inner body 15 by the high lift cam 11 in contact with the contact pad 17 of the body 14, and the inner body 15 The contacting valve receives the up and down movement of the outer body 14 to operate as a high lift.

In addition, the lock plate body 120 is installed in the longitudinal direction so that the return spring 122 is located above the lock plate 121, the return spring 122 when the oil exits through the HLA contact portion 210 As the lock plate 121 is moved backward and returned by the restoring force of), the inner body 15 and the outer body 14 are separated again and move independently, so that the valve is moved with the roller 18 of the inner body 15. It acts as a low lift in contact.

Therefore, in the low speed section of the part load, the valve operates as a low lift to suck air at a high speed, and in a full load condition, the valve operates as a high lift to inhale a large amount of air. .

However, in the case of applying the lock plate by connecting the inner body and the outer body in this way, both sides of the lock plate coupled to the inner body are inserted into the rear lower portion of the outer body and are locked. Due to processing problems, both lock plates are not locked at the same time.

Therefore, when the engine RPM is high, when one side is locked first, the moment is applied to the variable valve lift follower under the force of the cam, so the variable valve lift does not operate smoothly or if the variable valve lift follower is severe There is a problem that occurs when broken.

The present invention has been made in view of the above point, by connecting the inner body and the outer body using a lock pin, and fixing the starfish-shaped spring sheet between the lock pin and the return spring, in the high-speed section oil supply unit The oil flows through the spring seat, compresses the return spring, pushes the lock pin, and locks the outer body to the inner body by the lock pin.In the low speed section, the oil exits and the compressed return spring returns to its original position. As the locking pin, which was locked on the return, is unlocked, the inner body and the outer body become independent as the outer body receives the rotational movement of the high lift cam by the locking pin in the high speed section, and the lock pin is released in the low speed section. Valve that comes into contact with the inner body while being driven by An object of the present invention is to provide a variable valve lift follower device capable of absorbing a high speed air to improve the optimum performance, emission, and fuel economy effect according to each engine condition.

In the present invention for achieving the above object is a variable valve lift follower device three cams are applied to one valve,

A cam operating unit formed of a set of low lift cams in the center and high lift cams on both sides; An outer body having a contact pad formed on an upper surface thereof in contact with the high lift cam; An inner body coupled to the outer body to be independently driven, the inner body having a roller in contact with the low lift cam; A lock operating part mounted at a front end of the inner body to enable the lock pin to be protruded from the inside; A valve contact portion formed at a lower end of the lock operation portion; Characterized in that configured to include.

In a preferred embodiment, the lock operating portion:

A lock body having an oil supply portion formed at a bottom thereof; The lock body is mounted to move left and right in the high speed section and protrudes to the lower end of the outer body by the pressure of the oil filled through the oil supply section, and the low speed section discharges the oil and is inserted into the lock body by the return spring. pin; Characterized in that configured to include.

In a more preferred embodiment, the lockpin is:

A body part which is protruded from the lock body to the lower end of the outer body and has a constant diameter; A protrusion projecting from the end of the body portion to a relatively small diameter; A return spring inserted into the protrusion; A spring seat fixed to the lock body to be located between the body portion and the return spring; A snap ring fixed to one end of the return spring; Characterized in that configured to include.

In addition, the spring sheet is characterized in that the groove is formed in the radial direction along the circumferential direction.

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

5 is a perspective view showing a variable valve lift system according to the present invention, FIG. 6 is a perspective view showing a variable valve lift follower according to the present invention, and FIG. 7 is a perspective view showing a lock pin according to the present invention.

The present invention has an emphasis on connecting the outer body and the inner body using a lock pin to improve the problems of the conventional lock plate.

The present invention is a variable valve lift follower device for operating the valve as a high lift under the rotational movement of the high lift cam in the high-speed section according to the engine conditions, and operates as a low lift in the low-speed section. It is about.

The variable valve lift system applies three sets of cams per valve.

The set of cams has a low lift cam 10 at the center and a high lift cam 11 at both sides. The low lift cam 10 and the high lift cam 11 are arranged side by side with a different phase difference on the cam shaft 12 to rotate periodically.

At this time, the protrusion of the high lift cam 11 protrudes longer than the low lift cam 10.

The variable valve lift follower 13 device according to the present invention is the outer body 14 and the inner body 15 which are independently driven in contact with the lower portions of the lift cams 10 and 11, and the inner body according to the conditions of the engine. It consists of the lock operation part 16 which connects the body 15 to the outer body 14. As shown in FIG.

A contact pad 17 is integrally formed on the upper surface of the outer body 14 to be in contact with the two high lift cams 11. The contact pads 17 are curved in an approximate fan shape to form a high lift cam ( 11) It reduces friction and makes smooth movement when the projection rotates.

The roller 18 is mounted at the center of the inner body 15 to be in contact with the low lift cam 10. The roller 18 is also formed in a circular shape so as to friction when the protrusion of the low lift cam 10 rotates. It helps to reduce the weight and make the exercise smooth.

Here, the meaning that the outer body 14 and the inner body 15 are driven independently means that the outer body 14 and the inner body 15 are separated by the high lift cam 11 and the low lift cam 10, respectively. Is to move to.

A valve contact portion 19 is formed at one lower end of the inner body 15 to transfer the rotation of the lift cams 10 and 11 to the valve.

The front of the roller 18, the lock operation portion 16 is mounted to the inner body 15 serves to lock and release the inner body 15 and the outer body (14).

The lock operation unit 16 is a lock body (20), the lock pin (21) mounted to be movable left and right by the pressure of oil in the lock body (20) and the lock pin (21) originally It is composed of a return spring 22 to return to the position of.

An oil supply unit 20a is formed below the lock body 20, and the oil supply unit 20a receives oil from a hydraulic lash adjuster 23 (HLA). At this time, the hydraulic lash adjuster 23 is always filled with oil.

The lock pin 21 is composed of a cylindrical body portion 21a having a constant diameter and a protrusion 21b extending to a relatively small diameter at the end of the body portion 21a. At this time, the return spring 22 is inserted into the protrusion 21b.

The spring seat 24 is fixed to the lock body 20 and is in contact with the front end of the return spring 22.

The spring sheet 24 is a plate in which a groove is formed in the radial direction along the circumferential direction, that is, in the shape of a starfish. The structure of the spring seat 24 as described above also allows the return spring 22 to be compressed, but oil introduced through the oil supply unit 20a passes through the spring seat 24 to lock the lock pin 21. (20) Let them push out.

In addition, a snap ring 25 attached to the rear end of the return spring 22 is fixed to the end of the protrusion 21b of the lock pin 21.

Referring to the operation state of the follower device of the variable valve lift according to the present invention by such a configuration as follows.

FIG. 8A is a cross-sectional view taken along line “BB” of FIG. 6, and is an operation state diagram of the variable valve lift follower according to the present invention at a low speed section, and FIG. 8B is a cross-sectional view taken along line “BB” of FIG. 6. The operation state diagram of the variable valve lift follower according to the present invention in the section.

In low speed sections the valves should operate low lift, and in high speed sections the valves should operate high lift.

In the low speed section, the valve receives the rotational movement of the low lift cam 10 and moves up and down. In the high speed section, the valve receives the rotational movement of the high lift cam 11 and moves up and down.

The variable valve lift follower 13 according to the present invention selectively transmits rotational movements of the low lift cam 10 and the high lift cam 11 to the valve according to the conditions of the engine.

More specifically, in the low speed section, the valve is connected to the valve contact portion 19 formed at one lower end of the inner body 15, and the outer body 14 moves independently of the inner body 15, thereby providing a high lift cam ( The rotational movement of 11 is not transmitted to the valve and only the outer body 14 moves.

On the other hand, since the low lift cam 10 interlocked with the high lift cam 11 is in contact with the roller 18 of the inner body 15, the rotational movement of the low lift cam 10 is controlled by the inner body 15. By passing through the vertical movement of the valve, the valve opens for a relatively short time and air is sucked in at a high speed.

On the other hand, in the high speed section, the valve is connected to the valve contact portion 19 formed at one lower end of the inner body 15, the outer body 15 is moved by the lock operating portion 16 along the high lift cam 11 outer Having the same movement as the body 14, the rotational movement of the high lift cam 11 is transmitted to the valve in the vertical movement, thereby increasing the amount of air to be sucked in the valve is opened for a relatively long time.

That is, when the lock body 20 of the lock operation unit 16 is filled with oil supplied from the hydraulic lash adjuster 23 through the oil supply unit 20a, the oil passes through the groove of the spring seat 24. While the body 21a of the lock pin 21 is pushed out of the lock body 20, the inner body 15 is locked by the lock pin 21 at the lower end of the outer body 14.

At the same time, as the snap ring 25 coupled to the end of the return spring 22 is pushed to the lock body 20 along the protrusion 21b of the lock pin 21 under the pressure of the oil, the return spring 22 is The spring sheet 24 is to be compressed.

As the oil is released from the lock body 20 in the low speed section, the lock pin 21 is unlocked while moving to the original position by the restoring force of the return spring 22, so that the inner body 15 and the outer body 14 are removed. By moving independently of each other, only the rotational movement of the low lift cam 10 is transmitted to the valve in the vertical movement.

Therefore, the valve selectively receives the rotational movement of the high lift cam 11 and the low lift cam 10 by the lock pin 21 according to engine conditions, and moves up and down, so that air is sucked at a high speed in a low speed section. In high speed sections, a large amount of air is sucked in.

As described above, according to the variable valve lift follower apparatus according to the present invention, the valve is selectively received by the rotational movement of the high lift cam and the low lift cam by the lock pin according to the engine conditions to move up and down, In the air is sucked at a high speed, a large amount of air is sucked in the high-speed section, it is possible to improve the engine performance and fuel economy.

Claims (4)

In a variable valve lift follower device in which three cams are applied to one valve, A cam operating unit formed of a set of low lift cams in the center and high lift cams on both sides; An outer body having a contact pad formed on an upper surface thereof in contact with the high lift cam; An inner body coupled to the outer body to be independently driven, the inner body having a roller in contact with the low lift cam; A lock operating part mounted at a front end of the inner body to enable the lock pin to be protruded from the inside; A valve contact portion formed at a lower end of the lock operation portion; Variable valve lift follower device, characterized in that configured to include. The method according to claim 1, wherein the lock operating portion: A lock body having an oil supply portion formed at a bottom thereof; The lock body is mounted to move left and right in the high speed section and protrudes to the lower end of the outer body by the pressure of the oil filled through the oil supply section, and the low speed section discharges the oil and is inserted into the lock body by the return spring. pin; Variable valve lift follower device, characterized in that configured to include. The method according to claim 2, wherein the lock pin is: A body part which is protruded from the lock body to the lower end of the outer body and has a constant diameter; A protrusion projecting from the end of the body portion to a relatively small diameter; A return spring inserted into the protrusion; A spring seat fixed to the lock body to be located between the body portion and the return spring; A snap ring fixed to one end of the return spring; Variable valve lift follower device, characterized in that configured to include. The variable valve lift follower apparatus of claim 3, wherein the spring seat is a plate in which a groove is formed in a radial direction along a circumferential direction.

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