CN108167042B

CN108167042B - Variable timing system of engine

Info

Publication number: CN108167042B
Application number: CN201810093409.0A
Authority: CN
Inventors: 王梅俊; 刘旭; 黄永祥
Original assignee: Dongfeng Commercial Vehicle Co Ltd
Current assignee: Dongfeng Commercial Vehicle Co Ltd
Priority date: 2018-01-31
Filing date: 2018-01-31
Publication date: 2020-12-15
Anticipated expiration: 2038-01-31
Also published as: CN108167042A

Abstract

The utility model provides a variable timing system of engine, includes camshaft (1), timing gear (2), piston (6) and cylinder (12), and timing gear (2) are installed on camshaft (1), and processing of camshaft (1) outer lane has guide way I (15), and processing of timing gear (2) inner circle has guide way II (16) corresponding with guide way I (15), and camshaft (1) one end cover is put in piston (6), piston (6) cover put in cylinder (12), and be equipped with return spring (11) between piston (6) and camshaft (1) or between piston (6) and cylinder (12), piston (6) circumference arranged respectively with guide way I (15) and guide way II (16) matched with round pin axle (5), guide sleeve (9) and sealing washer (10) are installed to cylinder (12) inner circle. Simple structure, convenient installation and maintenance and low cost.

Description

Variable timing system of engine

Technical Field

The invention relates to a timing system, in particular to a variable timing system of an engine, and belongs to the technical field of correlation of engines.

Background

At present, referring to fig. 6 to 7, the conventional cam phaser mainly comprises a belt pulley 18, an impeller 19 and a camshaft 1, wherein the camshaft 1 is fixedly connected with the impeller 19, a plurality of first chambers 21 and second chambers 22 are formed between the belt pulley 18 and the impeller 19, the first chambers 21 are communicated with each other, and the second chambers 22 are communicated with each other; and a sealing ring II 20 is arranged between the belt pulley 18 and the impeller 19 so as to realize the isolation between the chambers. When the first chamber 21 flows in (flows out) the hydraulic oil and the second chamber 22 flows out (flows in) the hydraulic oil, the impeller 19 rotates a certain angle relative to the pulley 18 under the action of the hydraulic oil. Since the camshaft 1 and the impeller 19 are fixed relatively, the angle of the camshaft 1 relative to the pulley 18 is changed, so that the cam phase is changed, and the engine timing is changed.

However, this structure has the following drawbacks: 1. the structure is complicated, and the processing degree of difficulty is big: 1) the belt pulley 18 and the impeller 19 are complex in shape, and particularly various channels exist in the impeller 19, so that the mold opening and casting are needed; 2) the impeller 19 and the belt pulley 18 have high matching requirement, high surface roughness requirement and large integral processing difficulty. 2. The sealing and installation requirements are high: the independence between the first chamber 21 and the second chamber 22 is ensured, and the sealing points are too many, so the sealing requirement and the installation requirement are higher. 3. The mechanism has high cost: the whole mechanism is high in cost due to complex structure and high matching and sealing requirements.

Disclosure of Invention

The invention aims to provide a variable timing system of an engine aiming at the defects of complex structure, high sealing and mounting requirements, high manufacturing cost and the like of the conventional cam phaser.

In order to achieve the purpose, the technical solution of the invention is as follows: the variable timing system of the engine comprises a camshaft, a timing gear, a piston and a cylinder, wherein the timing gear is installed on the camshaft, a guide groove I is machined in the outer ring of the camshaft, a guide groove II corresponding to the guide groove I is machined in the inner ring of the timing gear, one end of the camshaft is sleeved in the piston, the inner ring of the piston is matched with the camshaft, the piston is sleeved in the cylinder, the outer ring of the piston is matched with the cylinder, a return spring is arranged between the piston and the camshaft or between the piston and the cylinder, pin shafts respectively matched with the guide groove I and the guide groove II are arranged in the circumferential direction of the piston, the cylinder is installed on a cover frame of a cylinder cover of the engine, and a guide sleeve and a sealing ring are installed on the inner ring of.

One end of the timing gear is abutted against a shaft shoulder on the camshaft, and the other end of the timing gear is abutted against a check ring on the piston.

And a pressure sensor is arranged in the cylinder.

The front end and the rear end of the guide groove I are flat grooves parallel to the axis, and the front end flat groove and the rear end flat groove are connected through an arc-shaped cutting groove.

And the guide groove II is parallel to the axis.

The number of the guide groove I, the guide groove II and the pin shaft is an integer which is larger than or equal to one.

Compared with the prior art, the invention has the beneficial effects that:

1. the variable cam timing mechanism comprises a timing gear, a cam shaft and a piston, wherein a guide groove I is processed on the outer ring of the cam shaft, a guide groove II corresponding to the guide groove I is processed on the inner ring of the timing gear, and pin shafts matched with the guide groove I and the guide groove II are circumferentially arranged on the piston; when the piston moves along the axial direction of the cylinder, the timing gear rotates relative to the camshaft under the action of the pin shaft, the guide groove I and the guide groove II, and therefore cam timing is changed. Compared with the existing cam phaser, the cam phaser has the advantages of simple structure, convenience in installation and maintenance and low cost.

2. The invention is characterized in that a pressure sensor is arranged in a cylinder and used for detecting the air pressure in the cylinder; the monitoring mechanism ensures the stability of the system and ensures high reliability of the system.

3. The inner ring of the cylinder is provided with the sealing ring, namely only the piston and the cylinder need to be sealed, so that the sealing requirement is low and the sealing is simple.

Drawings

FIG. 1 is a schematic diagram of the present invention.

Fig. 2 is a schematic view of a camshaft structure in the present invention.

FIG. 3 is a schematic view of the timing gear structure of the present invention.

Fig. 4 is a schematic view of the piston structure of the present invention.

Fig. 5 is a perspective view of the present invention.

Fig. 6 is a cross-sectional view of a prior art cam phaser.

Fig. 7 is a cross-sectional view of a prior art cam phaser.

In the figure, a camshaft 1, a timing gear 2, a bearing 3, a retainer ring 4, a pin shaft 5, a piston 6, a retainer ring 7, an engine cylinder cover frame 8, a guide sleeve 9, a seal ring 10, a return spring 11, a cylinder 12, a pressure sensor 13, a vent hole 14, a guide groove I15, a guide groove II 16, a shaft shoulder 17, a belt pulley 18, an impeller 19, a seal ring II 20, a first chamber 21 and a second chamber 22 are arranged.

Detailed Description

The invention is described in further detail below with reference to the following description of the drawings and the detailed description.

Referring to fig. 1, an engine variable timing system is a mechanism for changing the timing of an engine; including camshaft 1, timing gear 2, piston 6, and cylinder 12. The timing gear 2 is arranged on the camshaft 1, one end of the camshaft 1 is sleeved in the piston 6, and the inner ring of the piston 6 is matched with the camshaft 1; the piston 6 is sleeved in the cylinder 12, and the outer ring of the piston 6 is matched with the cylinder 12. The cylinder 12 is arranged on the engine cylinder cover frame 8; the inner ring of the cylinder 12 is provided with a guide sleeve 9 and a sealing ring 10 to ensure the normal movement of the piston 6. A return spring 11 is arranged between the piston 6 and the camshaft 1 or between the piston 6 and the cylinder 12, and when the return spring 11 is positioned between the piston 6 and the cylinder 12, the return spring is an extension spring; when the return spring 11 is located between the piston 6 and the camshaft 1, it is a compression spring; the return spring 11 serves to return the piston 6 to the initial position. The cylinder 12 is provided with a vent 14, and the introduction and discharge of gas are controlled by a solenoid valve or other mechanisms.

Referring to fig. 2 to 4, an outer ring of the camshaft 1 is machined with a guide groove i 15, and an inner ring of the timing gear 2 is machined with a guide groove ii 16 corresponding to the guide groove i 15; and pin shafts 5 matched with the guide grooves I15 and II 16 are arranged on the periphery of the piston 6 respectively, and the pin shafts 5 and the piston 6 are fixed in a certain mode (interference or welding and the like). When the piston 6 moves axially along the cylinder 12, the timing gear 2 rotates relative to the camshaft 1 by the pin 5, thereby changing the cam timing. The number of the guide grooves I15, the guide grooves II 16 and the pin shafts 5 can be designed to be an integer which is greater than or equal to one according to requirements, and the number of the guide grooves is 4 in the embodiment.

Referring to fig. 1, one end of the timing gear 2 is abutted against a shoulder 17 on the camshaft 1, and the other end of the timing gear 2 is abutted against a retainer ring 7 on the piston 6. The axial positioning of the timing gear 2 is realized by the shaft shoulder 17 and the retainer ring 7.

Referring to fig. 1, a pressure sensor 13 is installed in the cylinder 12 for detecting the air pressure in the cylinder 12. Of course, other sensors may be used instead, such as displacement and position sensors.

Referring to fig. 2 to 3, the front end and the rear end of the guide groove i 15 are flat grooves parallel to the axis, and the front end flat groove and the rear end flat groove are connected through an arc-shaped cutting groove; thus axially offsetting the guide groove i 15 by a certain angle. The guide groove II 16 is parallel to the axis. Of course, the shapes of the guide groove i 15 and the guide groove ii 16 may be interchanged, and not only the above shapes.

Referring to fig. 1 to 5, the piston 6 is at the right end of the cylinder 12 at the initial position, at this time, the engine is in a timing state i, the pin 5 is at the position of the flat groove at the right end of the guide groove i 15 and at the right end of the timing gear 2, and at this position, the return spring 11 still has a certain pretightening force. When the air cylinder 12 starts to introduce air, under the action of air pressure, the piston 6 overcomes the resistance of the spring 11, the guide groove I15 and the guide groove II 16 to the pin shaft 5 and gradually moves to the left until the leftmost end is reached; and after a certain amount of gas is continuously introduced to reach a certain set value, stopping introducing the gas, and keeping the engine in a timing state II. In the process, the guide groove I15 on the camshaft 1 is offset by a certain angle along the circumferential direction, and the guide groove II 16 on the timing gear 2 is not offset, so that the camshaft 1 and the timing gear 2 are angularly offset, the cam phase is changed, and the engine timing is changed.

Referring to fig. 1 to 5, when switching from the timing state 2 to the timing state 1, the cylinder 12 starts to deflate, and the piston 6 gradually moves to the right under the urging force of the spring 11. When the engine enters the arc-shaped cutting groove of the guide groove I15, the guide groove I15 applies a certain axial force to push the piston 6 to move right until the piston 6 reaches the rightmost position, and the engine is switched to a timing state I at the moment.

Referring to fig. 1 to 5, when in the timing state ii, if the cylinder 12 leaks, the piston 6 gradually moves to the right under the force of the spring 11. Because a section of flat groove is arranged on the left side of the guide groove I15, the timing of the engine cannot be changed at the moment, and the engine is still in a timing state II. During this time, the control system is informed of the gas leakage by the pressure sensor 13 and can send a signal to re-introduce gas into the cylinder 12 to ensure that the engine is in the timing state 2. Meanwhile, the control system sends out an error signal to prompt so that people can find the problem in time and repair the problem.

Referring to fig. 1 to 5, the system uses gas as a power source, and can be changed into hydraulic power, motor power and other power sources.

The foregoing is a more detailed description of the invention in connection with specific preferred embodiments and it is not intended that the invention be limited to these specific details. For those skilled in the art to which the invention relates, several simple deductions or substitutions may be made without departing from the spirit of the invention, and the above-mentioned structures should be considered as belonging to the protection scope of the invention.

Claims

1. An engine variable timing system comprising a camshaft (1), characterized in that: the timing mechanism is characterized by further comprising a timing gear (2), a piston (6) and a cylinder (12), wherein the timing gear (2) is installed on a camshaft (1), a guide groove I (15) is machined in the outer ring of the camshaft (1), a guide groove II (16) corresponding to the guide groove I (15) is machined in the inner ring of the timing gear (2), one end of the camshaft (1) is sleeved in the piston (6), the inner ring of the piston (6) is matched with the camshaft (1), the piston (6) is sleeved in the cylinder (12), the outer ring of the piston (6) is matched with the cylinder (12), a return spring (11) is arranged between the piston (6) and the camshaft (1) or between the piston (6) and the cylinder (12), pin shafts (5) respectively matched with the guide groove I (15) and the guide groove II (16) are circumferentially arranged on the piston (6), and the cylinder (12) is installed on an engine cylinder cover frame (8), guide sleeve (9) and sealing washer (10) are installed to cylinder (12) inner circle, cylinder (12) in install pressure sensor (13), guide way I (15) front end and rear end be the slotted wall parallel with the axis, link to each other through the arc grooving between front end slotted wall and the rear end slotted wall, guide way II (16) parallel with the axis, the quantity of guide way I (15), guide way II (16) and round pin axle (5) is for being more than or equal to an integer, shoulder (17) on timing gear (2) one end and the camshaft (1) are inconsistent, and the retaining ring (7) on timing gear (2) other end and piston (6) are inconsistent.