CN211343052U

CN211343052U - Fully variable electro-hydraulic valve system

Info

Publication number: CN211343052U
Application number: CN202020059818.1U
Authority: CN
Inventors: 王立峰; 王秀强; 吴龙龙; 王孟晓; 王昊天; 从田增; 吴鹏超; 苏明涛; 衣金水; 吴贝贝
Original assignee: Weifang Lichuang Electronic Technology Co Ltd
Current assignee: Weifang Lichuang Electronic Technology Co Ltd
Priority date: 2020-01-10
Filing date: 2020-01-10
Publication date: 2020-08-25
Anticipated expiration: 2030-01-10

Abstract

The utility model discloses a full variable electric liquid valve system, include: the limiting sleeve is fixed relative to the engine, the sliding sleeve and the limiting sleeve are rotatably mounted and are constrained by an axial limiting structure, the sliding sleeve is in transmission connection with the gear rack mechanism, the piston abuts against the valve assembly, and the screw shaft is axially controlled by a cam surface of the camshaft; the spiral shaft is provided with a spiral groove and a blocking part, and when the spiral groove is communicated with the limiting oil hole, the sliding sleeve cavity is communicated with a low-pressure oil path of the engine to release pressure; the axial bulge of the screw shaft is provided with a screw shaft abutting plane, and the head of the axial bulge of the piston is provided with a piston abutting plane. The utility model provides a because the machine oil in the sliding sleeve chamber runs off and influence the problem that the system normally worked to make and open the bent axle corner that corresponds constantly with the valve and keep unchangeable, be particularly suitable for using the control that has the (air) intake valve variable stroke of the engine of scavenging process.

Description

Fully variable electro-hydraulic valve system

Technical Field

The utility model relates to an engine valve mechanism technical field especially relates to a full variable electricity liquid valve system.

Background

The Fully Variable Valve System (FVVS) can realize continuous variation of the maximum lift of the Valve, the opening continuous angle of the Valve and the Valve timing, and has important significance for energy conservation and emission reduction of the engine. The FVVS can adopt the mode of early closing of the inlet valve (EIVC) to control the working medium quantity entering the cylinder, thereby canceling the throttle valve, the gasoline engine without the throttle valve can greatly reduce the pumping loss, and the fuel consumption in medium and small loads is reduced by 10-15%. The fully variable valve mechanism is matched with supercharging intercooling, so that the problems of deflagration and high heat load of an engine after supercharging can be solved, low-temperature combustion is realized on the premise of greatly improving the average effective pressure, the heat efficiency of the engine is improved, and the emission of harmful gas is reduced; therefore, the FVVS technology has become one of the important development directions of new internal combustion engine technology.

At present, a more advanced fully variable valve mechanism is a MultiAir (also known as UniAir) system developed by combining Schaeffler and Feiyat, the system adopts a camshaft-driven electro-hydraulic valve mechanism, and the valve motion law is controlled by combining a camshaft and an electromagnetic valve. The working principle of the system is as follows: the hydraulic piston is driven by the cam and is connected with the driving piston through a sliding sleeve cavity, and the sliding sleeve cavity is controlled by a switch type electromagnetic valve. When the electromagnetic valve is in a completely closed state, the hydraulic piston pushes the driving piston through the hydraulic pressure to transmit the hydraulic pressure generated by the rotation of the cam to the air valve; the intake valve is now fully cam controlled and in an open state. When the electromagnetic valve is in a fully open state, the liquid pressure can not transmit the driving force, the hydraulic piston can not push the driving piston, and the intake valve is no longer controlled by the cam and is in a fall-back or closed state. By controlling the opening and closing time of the electromagnetic valve, various different valve motion laws can be realized, and the function of the fully variable valve mechanism is realized. However, the electromagnetic valve has a complex structure and high price, and the popularization and application of the technology are limited.

In order to replace an expensive high-speed solenoid valve, chinese patent CN109339896A discloses a fully variable electro-hydraulic valve device with a buffer function, comprising: a camshaft and a valve assembly; the air valve assembly comprises a spiral shaft, a sliding sleeve, a piston and a return spring, wherein the spiral shaft and the piston are respectively connected with the sliding sleeve in a sliding and sealing mode, the piston abuts against the air valve assembly, a sealed sliding sleeve cavity is formed in the sliding sleeve by a space between the spiral shaft and the piston, and the return spring is clamped between the spiral shaft and the piston; the screw shaft is controlled by the cam surface of the camshaft in the axial direction; the peripheral wall of the spiral shaft, which is connected with the sliding sleeve in a sliding and sealing manner, is a spiral peripheral wall, the end part of the spiral shaft is provided with a control gear meshed with a rack, and the rack is driven by a linear actuating mechanism controlled by an engine electric control unit; the oil inlet hole and the limiting oil hole are formed in the sliding sleeve, the oil inlet hole is close to the spiral shaft, the limiting oil hole is close to the piston, the oil inlet hole and the limiting oil hole are respectively communicated with a low-pressure oil way of the engine, and a one-way valve is arranged on a connecting pipeline between the limiting oil hole and the low-pressure oil way of the engine. The invention adopts the screw shaft and the camshaft to jointly control the valve motion, changes the opening and closing time of the oil inlet hole by rotating the screw shaft, can realize the function of a fully variable valve mechanism, has high response speed and convenient control, replaces a high-speed electromagnetic valve with high price, and is suitable for a multi-cylinder engine.

However, in application it is found that: first, if the device is applied to the variable stroke control of the intake valve, since the engine is mostly designed with a scavenging process, the crank angle (relative to the top dead center) corresponding to the opening time of the intake valve is required to be constant, but the device can block the limit oil hole only at a certain time of the rising section of the cam surface, fig. 9 shows a set of crank angle/valve lift curve of the device, and shows that the crank angle corresponding to the opening time of the valve changes with the change of the blocking time of the limit oil hole, so the application of the device is limited. Secondly, in the stopping process of the engine, hydraulic oil in the sliding sleeve cavity can slowly leak, and when the engine is started, the sliding sleeve cavity can have an oil-free phenomenon, so that the system fails to work. Thirdly, the mechanism has the problem of too high seating speed in the process of seating the electro-hydraulic control valve, so that the sealing surfaces of the valve and the valve seat are damaged by impact, and the service life is influenced.

SUMMERY OF THE UTILITY MODEL

The above-mentioned not enough to prior art, the utility model provides a full variable electric liquid valve system to solve because the machine oil in the sliding sleeve chamber runs off and influence the problem of the normal work of system, and make the bent axle corner that corresponds constantly with the opening of inflating keep unchangeable.

In order to solve the technical problem, the utility model discloses following technical scheme:

a fully variable electro-hydraulic valve system, comprising: a camshaft and a valve assembly; the valve assembly comprises a sliding sleeve, a spiral shaft, a piston and a return spring, wherein the sliding sleeve is provided with a first end and a second end which are arranged oppositely, the sliding sleeve is provided with an oil inlet hole and a limiting oil hole, the spiral shaft is provided with a first end and a second end which are arranged oppositely, the spiral shaft is provided with a spiral structure, the spiral shaft and the piston are respectively connected with the sliding sleeve in a sliding and sealing manner, an inner cavity between the spiral shaft and the piston is called a sliding sleeve cavity, the return spring is clamped between the spiral shaft and the piston, the piston abuts against the valve assembly, and the spiral shaft is controlled by a cam surface of the camshaft in the axial direction; the gear rack mechanism comprises a control gear and a rack, and the rack is driven by a linear actuating mechanism controlled by an engine electronic control unit; a limiting sleeve is arranged outside the sliding sleeve, the limiting sleeve is fixed relative to the engine, the sliding sleeve and the limiting sleeve are rotatably mounted, the sliding sleeve is constrained by an axial limiting structure, the limiting sleeve is provided with a first limiting sleeve oil hole and a second limiting sleeve oil hole, the inner wall of the limiting sleeve is provided with a first annular groove and a second annular groove, the first limiting sleeve oil hole is communicated with the limiting oil hole through the first annular groove, the second limiting sleeve oil hole is communicated with the oil inlet hole through the second annular groove, the first limiting sleeve oil hole and the second limiting sleeve oil hole are respectively communicated with a low-pressure oil way of the engine, and a one-way valve is arranged on a connecting pipeline between the second limiting sleeve oil hole and the low-pressure oil way of the engine; the spiral structure comprises a spiral groove arranged on the circumferential surface of the spiral shaft, the groove surface of the spiral groove close to the first end of the spiral shaft is a spiral surface, the part between the spiral surface and the first end of the spiral shaft is a plugging part capable of plugging the limiting oil hole, the spiral groove is provided with an oil through hole, the oil through hole is communicated with the spiral groove and the sliding sleeve cavity, and when the spiral groove is communicated with the limiting oil hole, the sliding sleeve cavity is communicated with a low-pressure oil path of the engine for pressure relief; a screw shaft axial protruding part is arranged at the first end of the screw shaft, a screw shaft abutting plane is arranged on the screw shaft axial protruding part, a piston axial protruding part is arranged at one end, opposite to the screw shaft, of the piston, and a piston abutting plane is arranged at the head of the piston axial protruding part; the sliding sleeve is provided with a first positioning pin, the piston is provided with a first guide groove extending along the axial direction, and the first positioning pin extends into the first guide groove; the screw shaft is provided with a second guide groove, the second guide groove extends along the axial direction of the screw shaft, a second positioning pin extends into the second guide groove, and the second positioning pin is fixed relative to the engine; the control gear is arranged at the second end of the sliding sleeve, the gear rack mechanism is further provided with a limiting device and a return spring, when the return spring enables the rack to move to the limit position limited by the limiting device, the piston abutting plane abuts against the spiral shaft abutting plane, the limiting oil hole is blocked by the blocking part of the spiral shaft, and the valve lift of the valve assembly is controlled by the cam shaft.

When the screw shaft is controlled by the base circle section of the cam surface and the rack moves to the other limit position in the opposite direction of the limit device, the spiral groove is communicated with the limit oil hole.

The first end of the screw shaft is provided with two screw shaft axial protruding parts, and the heads of the two screw shaft axial protruding parts are respectively provided with a screw shaft abutting plane; the number of the piston axial protruding parts is two, the heads of the two piston axial protruding parts are respectively provided with a piston abutting plane, and the piston abutting planes correspond to the screw shaft abutting planes one by one.

The two pistons are abutted against the same plane, and the two screw shafts are abutted against the same plane.

The two piston abutting planes are symmetrically arranged relative to the center of the piston, and the two screw shaft abutting planes are symmetrically arranged relative to the center of the screw shaft.

And a thrust bearing is arranged at the second end of the spiral shaft, and a wear-resistant gasket is arranged between the thrust bearing and the cam surface of the cam shaft.

Wherein, the control gear is connected with the sliding sleeve in a torque transmission mode.

Wherein the rack is simultaneously meshed with the control gears of the plurality of screw shafts.

The linear actuating mechanism is a linear motor or an actuating electromagnet or an air cylinder or a hydraulic cylinder.

The first end of the sliding sleeve is provided with a stepped hole structure, the stepped hole structure comprises a large hole and a small hole, the small hole is matched with the sliding sealing surface of the piston, a buffer ring is arranged in the large hole, the buffer ring is sleeved on the sliding sealing surface of the piston and is in sliding sealing fit with the inner peripheral surface of the large hole, and the buffer ring and the piston form a buffer cavity in the stepped hole; the peripheral surface of the outer end of the piston is provided with a flange which is used for colliding the buffer ring when a valve of the valve assembly is seated, the end part of the piston of the sliding sleeve is provided with a baffle, and when the valve of the valve assembly is closed, a buffer distance is reserved between the buffer ring and the baffle; the sliding sleeve is provided with a buffer oil hole communicated with the buffer cavity, the limiting sleeve is provided with a limiting sleeve third oil hole, the inner wall of the limiting sleeve is provided with a third annular groove, the limiting sleeve third oil hole is communicated with the buffer oil hole through the third annular groove, and the limiting sleeve third oil hole is communicated with a low-pressure oil way of the engine through a throttling device.

The utility model adopts the above technical scheme after, its technological effect is:

1) the spiral shaft is provided with the spiral groove and the plugging part, before the spiral shaft is pushed by the cam surface to move downwards, the plugging part plugs the limiting oil hole, the piston is rigidly connected with the spiral shaft, and when the spiral shaft moves downwards, the valve is opened along with the spiral shaft, and the opening time is not changed all the time; and the spiral shaft continuously moves downwards, when the spiral groove is communicated with the limiting oil hole, the sliding sleeve cavity is communicated with a low-pressure oil way of the engine to release pressure, so that the valve is separated from the control of the cam surface, and the valve falls down to the seat to be closed under the action of the valve spring force. The communication time of the spiral groove and the limiting oil hole can be changed by rotating the sliding sleeve, and then the closing time of the valve is changed, so that the function of the fully variable valve mechanism can be realized, but the crank angle corresponding to the opening time of the valve is kept unchanged, so that the fully variable valve mechanism is particularly suitable for being applied to the control of the variable stroke of the intake valve of an engine with a scavenging process. When the valve returns, hydraulic oil enters the sliding sleeve cavity from the oil inlet hole, and rapidly resets the spiral shaft together with the reset spring, the linear actuating mechanism controlled by the engine electric control unit drives the sliding sleeve to rotate, the response speed is high, the control is convenient, and the high-speed electromagnetic valve with high price is replaced, so that the valve is suitable for a multi-cylinder engine.

2) After the ECU of the engine is shut down and the power is off, the rack moves to the limit position of the limiting device under the action of the return spring, the sliding sleeve drives the piston to rotate, at the moment, the abutting plane of the piston abuts against the abutting plane of the spiral shaft, engine oil does not work, the camshaft and the valve are in a rigid connection state, and the valve lift of the valve assembly is completely controlled by the camshaft, so that the influence of the loss of the engine oil on the normal work of the system is avoided.

3) When the valve is about to be seated, the piston firstly collides with the buffer ring, and because of the action of the throttling device, engine oil in the buffer cavity plays a damping role in the movement of the buffer ring, and the buffer ring moves slowly, so that the valve is slowly seated, the impact damage to the sealing surface of the valve and the valve seat is reduced, and the service life of the valve mechanism is effectively prolonged. When the valve descends again, the buffer ring moves downwards under the action of the pressure of the oil, and the buffer ring has enough time to move to the position of the baffle plate before the valve is seated again due to the short buffer distance; the valve buffering effect can be adjusted by adjusting the throttling effect and the buffering distance of the throttling device.

4) When the spiral shaft is controlled by the base circle section of the cam surface and the rack moves to the other limit position in the opposite direction of the limit device, the spiral groove is communicated with the limit oil hole, at the moment, the camshaft does not start to work, the spiral groove is communicated with the limit oil hole to release pressure, the piston stops moving, the valve is closed, and the cylinder stopping process of the engine can be realized.

Drawings

FIG. 1 is a cross-sectional view of an embodiment of the fully variable electro-hydraulic valve system of the present invention;

FIG. 2 is a schematic perspective view of the screw shaft of FIG. 1;

FIG. 3 is a schematic perspective view of the piston of FIG. 1;

FIG. 4 is a schematic structural diagram of a rack and pinion mechanism for driving the sliding sleeve in the embodiment shown in FIG. 1;

FIG. 5 is a schematic perspective view of the rack gear shown in FIG. 4 moving to the right to the extreme position of the limiting device, with the screw shaft and the corresponding abutment surface of the piston abutting against each other;

FIG. 6 is a cross-sectional view of a portion of the rack shown in FIG. 4 moved to the right to the limit of the stop and with the system in the starting position;

FIG. 7 is a cross-sectional view of a portion of the components of the system shown in FIG. 4 with the rack moved to the left to another extreme position and with the system in a cylinder deactivation state;

FIG. 8 is a crank angle/valve lift graph of the embodiment shown in FIG. 1;

FIG. 9 is a crank angle/valve lift graph of the disclosed technology referred to in the background;

in the figure, 101-camshaft, 102-spiral shaft, 102A-second guide groove, 102B-spiral shaft abutting plane, 102C-spiral shaft axial projection, 102D-spiral groove, 102E-spiral surface, 102F-oil through hole, 102G-blocking part, 103-sliding sleeve, 103A-control gear, 104-return spring, 105-piston, 105A-piston axial projection, 105B-piston abutting plane, 105C-first guide groove, 105D-flange, 106-valve assembly, 107-oil inlet hole, 108-check valve, 109-oil pan, 110-pressure retaining valve, 111-wear-resistant gasket, 112-thrust bearing, 113-rack, 114-pressure reducing valve, 115-return spring, 116-limiting device, 117-linear actuator, 118-limiting oil hole, 119-first positioning pin, 121-buffer ring, 122-baffle, 123-buffer oil hole, 124-throttling device, 125-limiting sleeve, 125A-limiting sleeve first oil hole, 125B-limiting sleeve second oil hole, 125-limiting sleeve third oil hole, 126-baffle ring, 127-second positioning pin, Q-sliding sleeve cavity, R-buffer cavity and S-buffer distance.

Detailed Description

The present invention will be further explained with reference to the drawings and examples.

As shown in fig. 1, a fully variable electro-hydraulic valve system, a stop collar 125 is disposed outside a sliding sleeve 103, the stop collar 125 is fixed relative to an engine, the sliding sleeve 103 and the stop collar 125 are rotatably mounted, and the sliding sleeve 103 is constrained by an axial stop structure, in this embodiment, the axial stop structure is a stop ring 126 and a flange which are located at two ends of the stop collar 125, the flange and the sliding sleeve 103 are integrated, and the stop ring 126 is fixedly connected with the sliding sleeve 103.

The screw shaft 102 and the piston 105 are respectively connected with the sliding sleeve 103 in a sliding and sealing mode, the screw shaft 102 is controlled by the cam surface of the camshaft 101 in the axial direction, and the piston 105 abuts against the valve assembly 106. In the sliding sleeve 103, a space between the screw shaft 102 and the piston 105 is a sliding sleeve cavity Q, the return spring 104 is clamped between the screw shaft 102 and the piston 105, and the common acting force of the return spring 104 and the oil pressure to the piston 105 is far smaller than the acting force of the valve spring to the piston 105.

The sliding sleeve 103 is provided with an oil inlet 107, a limiting oil hole 118 and a buffer oil hole 123, the limiting sleeve 125 is provided with a first limiting sleeve oil hole 125A, a second limiting sleeve oil hole 125B and a second limiting sleeve oil hole 125C, and the inner wall of the limiting sleeve 125 is provided with a first annular groove, a second annular groove and a third annular groove. The first oil hole 125A of the stop collar is communicated with the stop oil hole 118 through the first annular groove, the first oil hole 125A of the stop collar is communicated with the engine oil circuit through a pressure reducing valve 114 and is communicated with the oil pan 109 through a pressure retaining valve 110, the second oil hole 125B of the stop collar is communicated with the oil inlet hole 107 through the second annular groove, and the second oil hole 125B of the stop collar is connected with a one-way valve 108, is communicated with the engine oil circuit through the pressure reducing valve 114 and is communicated with the oil pan 109 through the pressure retaining valve 110; the buffer oil hole 123 is communicated with the buffer cavity R, the third oil hole 125C of the stop collar is communicated with the buffer oil hole 123 through the third annular groove, and the third oil hole 125C is connected with a throttling device 124, communicated with an engine oil circuit through a reducing valve 114 and communicated with the oil pan 109 through a pressure retaining valve 110. The engine oil line and the associated pressure reducing valve 114, pressure retaining valve 110, oil pan 109, etc. constitute a low-pressure oil line of the engine, and the throttle device may be a throttle valve or an orifice, etc.

The sliding sleeve 103 is provided with a first end and a second end which are oppositely arranged, the first end of the sliding sleeve 103 is provided with a stepped hole structure, the stepped hole structure comprises a large hole and a small hole, the small hole is matched with the sliding sealing surface of the piston 105, a buffer ring 121 is arranged in the large hole, the buffer ring 121 is sleeved on the sliding sealing surface of the piston 105 and is in sliding sealing fit with the inner peripheral surface of the large hole, and the buffer ring 121 and the piston 105 form a buffer cavity R in the stepped hole; the outer end peripheral surface of the piston 105 is provided with a flange 105D for hitting the cushion ring 121 when the valve of the valve assembly 106 is seated, a stopper plate 122 is attached to the piston end of the slide sleeve 103, and a cushion distance S is provided between the cushion ring 121 and the stopper plate 122 when the valve of the valve assembly 106 is closed.

The structure has a buffering function. When the valve is about to be seated, the piston 105 firstly collides with the buffer ring 121, and due to the action of the throttling device 124, the engine oil in the buffer cavity R plays a role in damping the motion of the buffer ring 121, and the buffer ring 121 slowly moves to make the valve be seated slowly, so that the impact damage to the sealing surfaces of the valve and a valve seat is reduced, and the service life of the valve mechanism is effectively prolonged. When the valve descends again, the buffer ring 121 moves downwards under the action of the oil pressure, and the buffer ring 121 has enough time to move to the position of the baffle 122 before the valve is seated again because the buffer distance S is short; the valve cushioning effect can be adjusted by adjusting the throttling effect and the cushioning distance of the throttling device 124.

As shown in fig. 1, 2 and 4, the second end of the sliding sleeve 103 is in transmission connection with a rack-and-pinion mechanism, the rack-and-pinion mechanism includes a control gear 103A and a rack 113, the control gear 103A is disposed at the second end of the sliding sleeve 103, and the rack 103 is driven by a linear actuator 117 controlled by an engine Electronic Control Unit (ECU). The control gear 103A is connected to the sliding sleeve 103 in such a manner as to be able to transmit torque. The linear actuator 117 is a mature technology, and may be a linear motor, an actuating electromagnet, an air cylinder, a hydraulic cylinder, or the like, and the connection relationship between the linear actuator and the rack 113 is well known to those skilled in the art, and will not be described herein.

As shown in fig. 1 and 2, the screw shaft 102 is provided with a second guide groove 102A, the second guide groove 102A extends in the axial direction of the screw shaft 102, a second positioning pin 127 extends into the second guide groove 102, the second positioning pin 127 is fixed with respect to the motor, and this structure enables the screw shaft 102 to move only in the axial direction and not to rotate.

The screw shaft 102 has a first end and a second end which are oppositely arranged, the screw shaft 102 is further provided with a spiral structure, the spiral structure comprises a spiral groove 102D which is arranged on the circumferential surface of the screw shaft 102, the groove surface of the spiral groove 102D which is close to the first end of the screw shaft 102 is a spiral surface 102E, the part between the spiral surface 102E and the first end of the screw shaft 102 is a blocking part 102G which can block the limit oil hole 118, the spiral groove 102D is provided with an oil through hole 102F, the oil through hole 102F is communicated with the spiral groove 102D and a sliding sleeve cavity Q, and when the spiral groove 102D is communicated with the limit oil hole 118, the sliding sleeve cavity Q is communicated with a.

As shown in fig. 2, a first end of the screw shaft 102 is provided with a screw shaft axial protrusion 102C, the screw shaft axial protrusion 102C is provided with a screw shaft abutting plane 102B, and in order to make the force more uniform when abutting, the first end of the screw shaft 102 is provided with two screw shaft axial protrusions 102C, and the two screw shaft axial protrusions 102C are respectively provided with one screw shaft abutting plane 102B. The two screw axes abut against the plane 102B in the same plane and are symmetrically arranged relative to the center of the screw axis 102.

As shown in fig. 1 and 3, the sliding sleeve 103 is provided with a first positioning pin 119, the piston 105 is provided with a first guide groove 105C extending along the axial direction, the first positioning pin 119 extends into the first guide groove 105C, and the rotational degree of freedom of the piston 105 relative to the sliding sleeve 103 is constrained by the first positioning pin 119, that is, the piston 105 can only move along the axial direction of the first guide groove 105C but cannot rotate, and when the sliding sleeve 103 rotates, the piston 105 can be driven to rotate together.

One end of the piston 105 opposite to the screw shaft 102 is provided with a piston axial direction protrusion 105A, and a head of the piston axial direction protrusion 105A is provided with a piston abutting plane 105B. In the same principle, in order to make the stress more balanced during the abutting, the number of the piston axial convex parts 105A is two, the heads of the two piston axial convex parts 105A are respectively provided with a piston abutting plane 105B, and the piston abutting planes 105B are in one-to-one correspondence with the screw shaft abutting planes 102B. The two piston abutment planes 105B are coplanar and symmetrically arranged with respect to the center of the piston 105.

The utility model discloses a screw axis and camshaft joint control valve motion's theory of operation is:

the engine oil in the engine oil path (low-pressure oil path) of the engine can flow to the sliding sleeve cavity Q through the oil inlet 107 and the limiting oil hole 118. Under the action of the camshaft 101, the screw shaft 102 moves downwards, when the blocking part 102G of the screw shaft 102 blocks the limiting oil hole 118 (at this time, the engine oil cannot flow out from the oil inlet hole 107 due to the action of the one-way valve 108), the sliding sleeve cavity Q becomes a closed cavity, the pressure of the hydraulic oil is increased, the piston 105 is pushed to move downwards, and the piston 105 pushes the valve to move downwards.

The linear actuator 117 controlled by the engine electric control unit drives the rack 113 to move to push the sliding sleeve 103 to rotate, when the sliding sleeve 103 rotates, the piston 105 can be driven to rotate together, after the piston abutting plane 105B is separated from the screw shaft abutting plane 102B, because the screw shaft 102 is provided with the spiral groove 102D and the blocking part 102G, when the screw shaft 102 is pushed by the cam surface to move downwards, the blocking part 102G firstly blocks the limiting oil hole 118, so that the piston 105 and the screw shaft 102 become rigid connection, the valve is opened along with the valve, and the opening time is not changed all the time. The spiral shaft 102 continues to move downwards, when the spiral groove 102D is communicated with the limiting oil hole 118, the sliding sleeve cavity Q is communicated with a low-pressure oil path of the engine to release pressure, so that the valve is separated from the control of the cam surface, and the valve pushes the piston to move upwards under the action of the valve spring force. If the screw shaft 102 does not block the limiting oil hole 118 any more in the process of closing the valve, the motion process of closing the valve is not affected by the cam surface and moves under the combined action of the spring force of the valve and the oil pressure. If the valve is closed, the screw shaft 102 returns upward along with the cam surface to block the limiting oil hole 118 again, at this time, the sliding sleeve cavity Q becomes a sealed cavity, and the valve motion rule is controlled by the cam surface along with the screw shaft 102. Because the cam surface, the spiral surface, the limiting oil hole and the like are all of mechanical structures and are fixed and unchangeable, the motion rule of the valve is fixed no matter the valve is closed in the mode, the valve is in a gradually increasing or decreasing relationship along with the rotation of the spiral shaft, and the change of the valve stroke is in a linear relationship with the rotation angle of the spiral shaft.

The communication time of the spiral groove 102D and the limiting oil hole 118 can be changed by rotating the sliding sleeve 103, and the closing time of the valve is further changed, so that the function of the full variable valve mechanism can be realized, but the crank angle corresponding to the opening time of the valve is always kept unchanged, so that the variable valve mechanism is particularly suitable for controlling the variable stroke of the intake valve of an engine with a scavenging process, as shown in FIG. 8.

In the return stroke, the hydraulic oil enters the sleeve chamber Q from the oil inlet 107 through the check valve 108, and rapidly returns the screw shaft 102 together with the return spring 104.

The utility model discloses in, after the engine shuts down the ECU outage, under return spring 115 effect, the extreme position that stop device 116 restricted is shifted to the rack 113 right side, at this moment, the positional relation of piston 105 and screw axis 102 is in the state shown in figure 5 and figure 6, the piston top leans on plane 105B top to lean on plane 102B in the screw axis top promptly, machine oil in the sliding sleeve chamber Q does not work, be in the rigid connection state between cam and valve, the valve lift is controlled by camshaft 1 completely to the influence that the normal work of system caused has been avoided machine oil to run off.

In the utility model, as shown in fig. 7, when the screw axis 102 is controlled by the base circle section of the cam surface, the rack 113 to when the opposite direction of the stop device 116 moves to another extreme position, the helical groove 102D with the spacing oilhole 118 intercommunication, at this moment, the camshaft 1 has not started working yet, and the helical groove 102D has just communicated the pressure release with the spacing oilhole 118, and afterwards, no matter the screw axis 102 is controlled by the base circle or the non-base circle section of the cam surface, the piston 105 will stop moving, and the valve is all in the closed state, can realize the cylinder deactivation process of engine.

The utility model discloses in, figure 4 shows the example of a rack 113 simultaneously with the meshing of 6 control gear 103A, and every control gear 103A corresponds a valve assembly, is applied to six jar engines promptly, the utility model discloses a design can be extended to 4 jar machines or 8 jar machines etc. the quantity of cylinder is unrestricted.

The utility model discloses in, be provided with thrust bearing 112 on control gear 103A's the terminal surface, be provided with wear pad 111 between thrust bearing 112 and the cam surface of camshaft 101, with reducing wear, and can lean on the distance between plane 105B and the screw axis top by plane 102B through the thickness adjustment piston top of wear pad 111, when the non-cam surface top of camshaft 101 leans on the screw axis 102 (or lean on through wear pad 111 and thrust bearing 112 top), distance between them is zero or is close to zero.

The present invention is not limited to the above embodiments, and all improvements based on the concept, principle, structure and method of the present invention will fall within the protection scope of the present invention.

Claims

1. A fully variable electro-hydraulic valve system, comprising:

a camshaft and a valve assembly;

the valve assembly comprises a sliding sleeve, a spiral shaft, a piston and a return spring, wherein the sliding sleeve is provided with a first end and a second end which are arranged oppositely, the sliding sleeve is provided with an oil inlet hole and a limiting oil hole, the spiral shaft is provided with a first end and a second end which are arranged oppositely, the spiral shaft is provided with a spiral structure, the spiral shaft and the piston are respectively connected with the sliding sleeve in a sliding and sealing manner, an inner cavity between the spiral shaft and the piston is called a sliding sleeve cavity, the return spring is clamped between the spiral shaft and the piston, the piston abuts against the valve assembly, and the spiral shaft is controlled by a cam surface of the camshaft in the axial direction;

the gear rack mechanism comprises a control gear and a rack, and the rack is driven by a linear actuating mechanism controlled by an engine electronic control unit; it is characterized in that the preparation method is characterized in that,

a limiting sleeve is arranged outside the sliding sleeve, the limiting sleeve is fixed relative to the engine, the sliding sleeve and the limiting sleeve are rotatably mounted, the sliding sleeve is constrained by an axial limiting structure, the limiting sleeve is provided with a first limiting sleeve oil hole and a second limiting sleeve oil hole, the inner wall of the limiting sleeve is provided with a first annular groove and a second annular groove, the first limiting sleeve oil hole is communicated with the limiting oil hole through the first annular groove, the second limiting sleeve oil hole is communicated with the oil inlet hole through the second annular groove, the first limiting sleeve oil hole and the second limiting sleeve oil hole are respectively communicated with a low-pressure oil way of the engine, and a one-way valve is arranged on a connecting pipeline between the second limiting sleeve oil hole and the low-pressure oil way of the engine;

the spiral structure comprises a spiral groove arranged on the circumferential surface of the spiral shaft, the groove surface of the spiral groove close to the first end of the spiral shaft is a spiral surface, the part between the spiral surface and the first end of the spiral shaft is a plugging part capable of plugging the limiting oil hole, the spiral groove is provided with an oil through hole, the oil through hole is communicated with the spiral groove and the sliding sleeve cavity, and when the spiral groove is communicated with the limiting oil hole, the sliding sleeve cavity is communicated with a low-pressure oil path of the engine for pressure relief;

a screw shaft axial protruding part is arranged at the first end of the screw shaft, a screw shaft abutting plane is arranged on the screw shaft axial protruding part, a piston axial protruding part is arranged at one end, opposite to the screw shaft, of the piston, and a piston abutting plane is arranged at the head of the piston axial protruding part;

the sliding sleeve is provided with a first positioning pin, the piston is provided with a first guide groove extending along the axial direction, and the first positioning pin extends into the first guide groove; the screw shaft is provided with a second guide groove, the second guide groove extends along the axial direction of the screw shaft, a second positioning pin extends into the second guide groove, and the second positioning pin is fixed relative to the engine;

the control gear is arranged at the second end of the sliding sleeve, the gear rack mechanism is further provided with a limiting device and a return spring, when the return spring enables the rack to move to the limit position limited by the limiting device, the piston abutting plane abuts against the spiral shaft abutting plane, the limiting oil hole is blocked by the blocking part of the spiral shaft, and the valve lift of the valve assembly is controlled by the cam shaft.

2. The fully variable electro-hydraulic valve system according to claim 1, wherein the spiral groove communicates with the stopper oil hole when the spiral shaft is controlled by the base circle section of the cam surface and the rack moves to another limit position in the opposite direction of the stopper.

3. The fully variable electro-hydraulic valve system according to claim 1, wherein the first end of the screw shaft is provided with two screw shaft axial protrusions, and the heads of the two screw shaft axial protrusions are respectively provided with one screw shaft abutting plane; the number of the piston axial protruding parts is two, the heads of the two piston axial protruding parts are respectively provided with a piston abutting plane, and the piston abutting planes correspond to the screw shaft abutting planes one by one.

4. The fully variable electro-hydraulic valve system of claim 3, wherein the two pistons abut against a plane and the two screw spindles abut against a plane.

5. The fully variable electro-hydraulic valve system of claim 4, wherein two of the piston abutment planes are symmetrically disposed with respect to a center of the piston, and two of the screw axis abutment planes are symmetrically disposed with respect to a center of the screw axis.

6. The fully variable electro-hydraulic valve system according to claim 1, wherein a thrust bearing is provided at the second end of the screw shaft, and a wear pad is provided between the thrust bearing and the cam surface of the camshaft.

7. The fully variable electro-hydraulic valve system of claim 1, wherein the control gear is connected to the sliding sleeve in a torque transmitting manner.

8. The fully variable electro-hydraulic valve system of claim 1, wherein the rack gear is simultaneously engaged with the control gears of a plurality of the screw spindles.

9. The fully variable electro-hydraulic valve system of claim 1, wherein the linear actuator is a linear motor or an actuator electromagnet or a pneumatic or hydraulic cylinder.

10. The fully variable electro-hydraulic valve system of claim 1, wherein the first end of the sliding sleeve is provided with a stepped bore structure comprising a large bore and a small bore, the small bore being engaged with the sliding seal surface of the piston, the large bore having a cushion ring disposed therein, the cushion ring being fitted over the sliding seal surface of the piston and being in sliding sealing engagement with an inner peripheral surface of the large bore, the cushion ring and the piston forming a cushion chamber within the stepped bore; the peripheral surface of the outer end of the piston is provided with a flange which is used for colliding the buffer ring when a valve of the valve assembly is seated, the end part of the piston of the sliding sleeve is provided with a baffle, and when the valve of the valve assembly is closed, a buffer distance is reserved between the buffer ring and the baffle;

the sliding sleeve is provided with a buffer oil hole communicated with the buffer cavity, the limiting sleeve is provided with a limiting sleeve third oil hole, the inner wall of the limiting sleeve is provided with a third annular groove, the limiting sleeve third oil hole is communicated with the buffer oil hole through the third annular groove, and the limiting sleeve third oil hole is communicated with a low-pressure oil way of the engine through a throttling device.