CN108590800B

CN108590800B - Mechanical variable valve driving mechanism

Info

Publication number: CN108590800B
Application number: CN201810179657.7A
Authority: CN
Inventors: 张翔宇; 杨震寰; 黄树和; 李研芳; 刘胜; 梁红波
Original assignee: China North Engine Research Institute Tianjin
Current assignee: China North Engine Research Institute Tianjin
Priority date: 2018-03-05
Filing date: 2018-03-05
Publication date: 2020-07-24
Anticipated expiration: 2038-03-05
Also published as: CN108590800A

Abstract

The invention provides a mechanical variable valve driving mechanism, which comprises a cam and a gear, wherein a first molded line and a second molded line are arranged on the outer circumferential surface of the cam, a plunger sleeve is sleeved inside the gear and can rotate around the plunger sleeve, and when the gear rises relative to the plunger sleeve, the first molded line is in contact fit with the top end of the gear; when the gear reduces for the plunger bushing, the second molded lines and the top contact cooperation of plunger bushing, the inside plunger that cup joints of plunger bushing, plunger bottom fixed connection valve sleeve, the mounting is cup jointed to the valve sleeve outside, the below installation valve, and the valve middle part is equipped with valve spring, bottom and connection valve seat. The mechanical variable valve driving mechanism does not need to operate the control mechanism under each working cycle, but can be adjusted under the working condition that the stroke needs to be changed, is simple to control, and is beneficial to the engineering application of the variable valve technology.

Description

Mechanical variable valve driving mechanism

Technical Field

The invention belongs to the field of engines, and particularly relates to a mechanical variable valve driving mechanism.

Background

Internal combustion engines are still the prime mover with the highest thermal efficiency and the largest power per unit volume and weight, and have wide application, however, with the gradual shortage of world energy and the continuous deterioration of environmental resources, the internal combustion engines are required to meet more strict emission regulations and economic indexes. The traditional internal combustion engine adopts a camshaft with a fixed molded line to drive a valve, so that the emission and the oil consumption of the internal combustion engine cannot be optimal at all working conditions, and therefore, most of novel internal combustion engines adopt a variable valve technology to control the emission and reduce the oil consumption.

The variable valve technology is mainly divided into a variable valve distribution technology based on a camshaft and a cam-free valve distribution technology at present. The former mainly changes the mechanical structure, so the structure is simple, the response speed is fast, but because the cam is kept, the valve is only relatively variable, and can not be arbitrarily variable. The valve timing, lift and duration can be changed at will by the cam-free valve distribution technology. The driving mode is divided into two modes, namely electromagnetic driving, electric driving, motor driving, electro-hydraulic driving and the like. Compared with the defects of high energy consumption of electromagnetic drive, low and unstable response speed of electric drive, complex system of motor drive and the like, the electro-hydraulic drive cam-free gas distribution technology has the advantages of relatively simple structure and relatively high response speed. However, it also has unavoidable disadvantages: the flow of the hydraulic system is insufficient at high rotating speed, the valve reaches the maximum lift and the seating position quickly, and the impact force is large. Therefore, the valve stroke control device is mainly used for engines with low rotating speed such as diesel engines, and besides, expensive electro-hydraulic servo systems and relatively complex control technologies are required to accurately control the valve stroke to avoid seating impact, so that the cost of the engine is greatly increased. Accordingly, it is desirable to employ suitable variable valve technology for specific engine applications.

It is known that, as described in the patent of invention (title: multimode 2-stroke/4-stroke internal combustion engine; patent No. 200880102440.0), the combustion frequency can be doubled by switching the engine stroke from 4-stroke operation to 2-stroke operation, and doubling of the engine power can be achieved even when the output work per cycle is the same. Therefore, it is necessary to research a valve mechanism with low energy consumption, simple structure and flexibility and variability to realize the 2/4 stroke interchange function.

Disclosure of Invention

In view of this, the present invention provides a mechanical variable valve driving mechanism, which changes the matching rule between the cam profile and the gear and the plunger sleeve, so as to change the matching relationship between the cam and the valve, and finally realize the 2/4 stroke interchange function.

In order to achieve the purpose, the technical scheme of the invention is realized as follows:

a mechanical variable valve driving mechanism comprises a cam, a plunger sleeve, a gear, a valve mechanism and a plunger, wherein the bottom of the plunger sleeve is in driving connection with the valve mechanism, the plunger is sleeved inside the plunger, the gear is sleeved outside the plunger sleeve, the gear is connected with a control rod outside the gear, the control rod controls the gear to do relative lifting rotary motion around the plunger sleeve, a pair of first molded lines and a pair of second molded lines are arranged on the outer circumferential surface of the cam, and when the gear rises relative to the plunger sleeve, the first molded lines are in contact fit with the top end of the gear; when the gear is lowered relative to the plunger sleeve, the second molded line is in contact fit with the top end of the plunger sleeve.

Further, the first molded line is in a double peach shape, and when the first molded line is in contact fit with the top end of the gear, the first molded line drives the plunger sleeve twice every time the cam rotates for one circle.

Furthermore, the second molded line is in a single peach shape, and when the second molded line is in contact fit with the top end of the plunger sleeve, the second molded line drives the plunger sleeve once every time the cam rotates for one circle.

Further, the gear, the plunger sleeve and the plunger are coaxial.

Furthermore, a chute is formed in the inner rotating surface of the gear, and a first bump matched with the chute is fixedly arranged on the outer rotating surface of the plunger sleeve.

Furthermore, a first groove is formed in the rotary surface in the plunger sleeve along the axial direction, and a second bump matched with the first groove is fixedly arranged on the outer rotary surface of the plunger.

Furthermore, a second groove is formed in the inner rotary surface of the fixing piece in the axial direction, and a third bump matched with the second groove is fixedly arranged on the outer rotary surface of the valve sleeve.

Furthermore, a straight gear is arranged on the control rod.

Further, the ratio of the cam rotation speed to the engine rotation speed is 1: 2.

Further, the valve mechanism comprises a fixing piece, a valve seat, a valve spring and a valve sleeve, the top of the valve sleeve is fixedly connected with the plunger, the fixing piece is sleeved outside the valve sleeve, the valve is installed below the fixing piece, the valve spring is arranged in the middle of the valve, and the bottom of the valve is connected with the valve seat in a matched mode.

Compared with the prior art, the mechanical variable valve driving mechanism has the following advantages:

(1) the mechanical variable valve driving mechanism does not need to operate the control mechanism under each working cycle, but can be adjusted under the working condition that the stroke needs to be changed, is simple to control, and is beneficial to the engineering application of the variable valve technology.

(2) According to the mechanical variable valve driving mechanism, the control rod is arranged, and the rotation of the gear can be controlled through linear movement, so that the gear can move up and down relative to the plunger sleeve.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the invention without limitation. In the drawings:

FIG. 1 is a schematic illustration of an embodiment of the present invention with the valve open in a 4-stroke condition;

FIG. 2 is a schematic illustration of the embodiment of the present invention with the valve closed in a 4-stroke condition;

FIG. 3 is a schematic view of the embodiment of the present invention with the valve open in the 2-stroke condition;

FIG. 4 is a schematic illustration of the embodiment of the present invention with the valve closed in a 2-stroke condition;

FIG. 5 is a front view of a cam in an embodiment of the present invention;

FIG. 6 is a side view of a cam in an embodiment of the present invention;

FIG. 7 is a top view of a cam in an embodiment of the present invention;

FIG. 8 is a top plan view of the plunger sleeve of FIG. 1 mated with the plunger;

FIG. 9 is an internal schematic view of a gear in an embodiment of the present invention;

FIG. 10 is a schematic view of a gear engaged with a lever in an embodiment of the present invention;

fig. 11 is a top view of the valve sleeve of fig. 1 engaged with a retainer.

Description of reference numerals:

1-a cam; 11-a first profile; 12-a second profile; 2-plunger sleeve; 21-a first bump; 3-a gear; 31-a chute; 4-a fixing piece; 5-valve seat; 6-valve; 7-valve spring; 8-valve sleeves; 9-a plunger; 10-control lever.

Detailed Description

It should be noted that the embodiments and features of the embodiments of the present invention may be combined with each other without conflict.

In the description of the present invention, it is to be understood that the terms "central," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like are used in the orientation or positional relationship indicated in the drawings, which are merely for convenience in describing the invention and to simplify the description, and are not intended to indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and are therefore not to be construed as limiting the invention. Furthermore, the terms "first", "second", etc. are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first," "second," etc. may explicitly or implicitly include one or more of that feature. In the description of the invention, the meaning of "a plurality" is two or more unless otherwise specified.

In the description of the invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted", "connected" and "connected" are to be construed broadly, e.g. as being fixed or detachable or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the creation of the present invention can be understood by those of ordinary skill in the art through specific situations.

The invention will be described in detail with reference to the following embodiments with reference to the attached drawings.

A mechanical variable valve driving mechanism, as shown in fig. 1 to 11, comprising a cam 1, a plunger sleeve 2, a gear 3, a valve mechanism and a plunger 9, wherein the bottom of the plunger sleeve 2 is in driving connection with the valve mechanism, the plunger 9 is sleeved inside the plunger sleeve 2, the gear 3 is sleeved outside the plunger sleeve, the gear 3 is connected with a control rod 10 outside the plunger sleeve, the control rod 10 controls the gear 3 to perform relative lifting and lowering rotary motion around the plunger sleeve 2, a pair of first molded lines 11 and a pair of second molded lines 12 are arranged on the outer circumferential surface of the cam 1, and when the gear 3 is lifted relative to the plunger sleeve 2, the first molded lines 11 are in contact fit with the top end of the gear 3; when the gear wheel 3 is lowered relative to the plunger sleeve 2, the second profile 12 is in contact engagement with the top end of the plunger sleeve 2.

The first molded line 11 is in a double peach shape, and when the first molded line 11 is in contact fit with the top end of the gear 3, the first molded line 11 drives the plunger sleeve 2 twice every time the cam 1 rotates one circle.

The second molded line 12 is in a single peach shape, and when the second molded line 12 is in contact fit with the top end of the plunger sleeve 2, the second molded line 12 drives the plunger sleeve 2 once every time the cam 1 rotates for one circle.

The gear 3, the plunger sleeve 2 and the plunger 9 are coaxial, so that the gear 3 can only move up and down relative to the plunger sleeve 2 under the action of the control rod 10, and the failure of a driving mechanism is effectively prevented.

The inner rotary surface of the gear 3 is provided with a chute 31, and the outer rotary surface of the plunger sleeve 2 is fixedly provided with a first bump 21 matched with the chute 31.

And a first groove is formed in the inner rotary surface of the plunger sleeve 2 along the axial direction, and a second convex block matched with the first groove is fixedly arranged on the outer rotary surface of the plunger 9.

The inner rotary surface of the fixing piece 4 is provided with a second groove along the axial direction, and the outer rotary surface of the valve sleeve 8 is fixedly provided with a third lug matched with the second groove.

A straight gear is arranged on the control rod 10.

The ratio of the rotating speed of the cam 1 to the rotating speed of the engine is 1: 2.

The valve mechanism comprises a fixing part 4, a valve seat 5, a valve 6, a valve spring 7 and a valve sleeve 8, the top of the valve sleeve 8 is fixedly connected with a plunger 9, the fixing part 4 is sleeved outside, the valve 6 is installed below, the valve spring 7 is arranged in the middle of the valve 6, and the bottom of the valve spring is connected with the valve seat 5 in a matching mode.

The working process of the mechanical variable valve driving mechanism is as follows:

as shown in fig. 8, since the inner rotating surface of the plunger sleeve 2 is provided with a first groove along the axial direction, and the outer rotating surface of the plunger 9 is fixedly provided with a second bump which is matched with the first groove, the plunger sleeve 2 can only move along the axial direction, but cannot rotate around the axis of the plunger sleeve;

as shown in fig. 8 to 10, since the inner rotating surface of the gear 3 is provided with the inclined groove 31 and the outer rotating surface of the plunger sleeve 2 is fixedly provided with the first protrusion 21 engaged with the inclined groove 31, the plunger sleeve 2 can be moved upward or downward relative to the gear 3 by controlling the rotation of the gear 3 by the linear movement of the control rod 10 (see fig. 10).

As shown in fig. 11, since the inner rotary surface of the fixing member 4 is provided with a second groove along the axial direction, and the outer rotary surface of the valve sleeve 8 is fixedly provided with a third protrusion which is matched with the second groove, the valve sleeve 8 and the plunger 9 fixed at the top end of the valve sleeve 8 can only move along the axial direction, but cannot rotate around the axis of the valve sleeve 8;

in fig. 1 and 2, the rotation of the gear 3 is controlled by a control rod 10, so that the gear 3 is lowered relative to the plunger sleeve 2, the second profile 12 is matched with the top end of the plunger sleeve 2, and the plunger sleeve 2, the gear 3, the valve sleeve 8 and the valve 6 can be integrated. The first profile 11 is not in contact with the gear wheel 3, so that the law of motion of the first profile 11 has no influence on the gear wheel 3. In fig. 1, the second profile 12 is in a convex state, and at this time, the second profile 12 drives the plunger sleeve 2 and the valve 6, and the valve 6 is away from the valve seat 5 against the acting force of the valve spring 7, so that the valve 6 is opened. In fig. 2, the second profile 12 is in a base circle state, and at this time, the second profile 12 has no driving effect on the plunger barrel 2 and the valve 6, so that the valve 6 is in a closed state under the pre-tightening force of the valve spring 7. Since the second profile 12 is in the shape of a single peach and the ratio of the rotation speed of the cam 1 to the rotation speed of the engine is 1:2, the second profile 12 can drive the plunger sleeve 2 and the valve 6 once per two engine revolutions, so that the engine works once, thereby achieving a four-stroke mode.

In fig. 3 and 4, the rotation of the gear 3 is controlled by a control rod 10, so that the gear 3 is lifted relative to the plunger barrel 2, and the first molded line 11 is matched with the top end of the gear 3, so that the gear 3, the plunger barrel 2, the valve sleeve 8 and the valve 6 can be integrated. The second profile 12 is not in contact with the gear wheel 3, so that the law of motion of the second profile 12 has no influence on the gear wheel 3. In fig. 3, the first profile 11 is in a convex state, and at this time, the first profile 11 drives the gear 3, the plunger sleeve 2, and the valve 6 is moved away from the valve seat 5 against the acting force of the valve spring 7, so that the valve 6 is opened. In fig. 4, the first profile 11 is in a base circle state, and at this time, the first profile 11 has no driving effect on the gear 3, the plunger sleeve 2, and the valve 6, so that the valve 6 is in a closed state under the pre-tightening force of the valve spring 7; because the first molded line 11 is in a double-peach shape, and the ratio of the rotating speed of the cam 1 to the rotating speed of the engine is 1:2 so that for every two engine revolutions, the cam 1 makes one revolution, the first profile 11 can drive the gear 3, the plunger barrel 2 and the valve 6 twice, causing the engine to work twice, thus being in two-stroke mode.

It is worth noting that if the plunger sleeve 2 and the plunger 9 can not only move axially but also rotate around their own axes, the control rod 10 can cause the gear 3 to rotate synchronously with the plunger sleeve 2 and the plunger 9 during the rotation of the control gear 3, so that the gear 3 does not move up and down relative to the plunger sleeve 2, and the mechanism fails.

In summary, by changing the linear motion displacement of the control rod 10, the matching rule between the cam 1 and the gear 3 and between the cam sleeve 2 can be changed, and finally, the motion rule of the valve 6 is changed, so that 2/4 stroke variation is realized. The invention does not need to operate the control mechanism under each working cycle, but can adjust under the working condition that the stroke needs to be changed, has simple control and is beneficial to the engineering application of the variable valve technology.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and should not be taken as limiting the invention, so that any modifications, equivalents, improvements and the like, which are within the spirit and principle of the present invention, should be included in the scope of the present invention.

Claims

1. A mechanical variable valve actuation mechanism characterized in that: comprises a cam (1), a plunger sleeve (2), a gear (3), a valve mechanism and a plunger (9),

the bottom of the plunger sleeve (2) is in driving connection with a valve mechanism, the plunger (9) is sleeved inside the plunger sleeve, the gear (3) is sleeved outside the plunger sleeve, the gear (3) is connected with a control rod (10) outside the gear, a chute (31) is arranged on the inner rotating surface of the gear (3), a first bump (21) matched with the chute (31) is fixedly arranged on the outer rotating surface of the plunger sleeve (2), and the control rod (10) controls the gear (3) to rotate around the plunger sleeve (2) in a relatively lifting manner through linear movement,

the outer circumferential surface of the cam (1) is provided with a pair of first molded lines (11) and a pair of second molded lines (12), and when the gear (3) rises relative to the plunger sleeve (2), the first molded lines (11) are in contact fit with the top end of the gear (3); when the gear (3) is lowered relative to the plunger sleeve (2), the second molded line (12) is in contact fit with the top end of the plunger sleeve (2).

2. The mechanical variable valve driving mechanism according to claim 1, characterized in that: the first molded line (11) is in a double peach shape, and when the first molded line (11) is in contact fit with the top end of the gear (3), the first molded line (11) drives the plunger sleeve (2) twice every time the cam (1) rotates for one circle.

3. The mechanical variable valve driving mechanism according to claim 1, characterized in that: the second molded line (12) is in a single peach shape, and when the second molded line (12) is in contact fit with the top end of the plunger sleeve (2), the second molded line (12) drives the plunger sleeve (2) once every circle of the cam (1).

4. The mechanical variable valve driving mechanism according to claim 1, characterized in that: the gear (3), the plunger sleeve (2) and the plunger (9) are coaxial.

5. The mechanical variable valve driving mechanism according to claim 1, characterized in that: the valve mechanism comprises a fixing piece (4), a valve seat (5), a valve (6), a valve spring (7) and a valve sleeve (8), the top of the valve sleeve (8) is fixedly connected with a plunger (9), the outside of the valve sleeve is sleeved with the fixing piece (4), the lower portion of the valve sleeve is installed on the valve (6), the middle of the valve (6) is provided with the valve spring (7), and the bottom of the valve spring is connected with the valve seat (5) in a matching mode.

6. The mechanical variable valve driving mechanism according to claim 1, characterized in that: the inner rotary surface of the plunger sleeve (2) is axially provided with a first groove, and the outer rotary surface of the plunger (9) is fixedly provided with a second bump matched with the first groove.

7. The mechanical variable valve driving mechanism according to claim 5, characterized in that: the inner rotary surface of the fixing piece (4) is provided with a second groove along the axial direction, and the outer rotary surface of the valve sleeve (8) is fixedly provided with a third bump matched with the second groove.

8. The mechanical variable valve driving mechanism according to claim 1, characterized in that: a straight gear is arranged on the control rod (10).

9. The mechanical variable valve driving mechanism according to claim 1, characterized in that: the ratio of the rotating speed of the cam (1) to the rotating speed of the engine is 1: 2.