CN105804820A

CN105804820A - Variable valve lift (VVL) cam shaft structure

Info

Publication number: CN105804820A
Application number: CN201610152738.9A
Authority: CN
Inventors: 秦天
Original assignee: Individual
Current assignee: Individual
Priority date: 2016-03-17
Filing date: 2016-03-17
Publication date: 2016-07-27
Anticipated expiration: 2036-03-17
Also published as: CN105804820B

Abstract

The invention discloses a variable valve lift (VVL) cam shaft structure and particularly relates to a VVL cam shaft structure applied to the field of automobile engines. By means of the VVL cam shaft structure provided by the invention, impact of an engine can be avoided in the process of mutually switching of the high-speed working state and the low-speed working state, parts of a cam shaft can be effectively protected, the service life of mechanical parts can be greatly prolonged, the machining difficulty is remarkably lowered, and the finished product rate is increased. The VVL cam shaft structure comprises a central spindle and cam assemblies and further comprises end cams. The cam assemblies are arranged on the central spindle in a sleeving mode. The end cams make contact with the two end faces of the cam assemblies. Radial cam structures are further disposed on the end cams. The end cams are adopted so as to drive the cam assemblies to move relative to the central spindle, thus smooth and steady switching of high-speed and low-speed working conditions can be achieved, fast, accurate and small-impact effects can be achieved in the switching process of high-speed cams and low-speed cams, the damage to the mechanical parts due to high-speed and low-speed switching is reduced, the durability of the VVL cam shaft is improved, and the service life is prolonged.

Description

VVL camshaft structure

Technical field

The present invention relates to a kind of VVL camshaft structure, especially a kind of VVL camshaft structure for automotive engine applications.

Background technology

The port timing mechanism of electromotor is responsible for providing gasoline combustion acting necessary fresh air to cylinder, and the waste gas after burning is discharged, from operation principle, the major function of port timing mechanism is to open and close the inlet and outlet door of each cylinder according to certain time limit, thus realizing the whole process of cylinder ventilation supply.For the common engine not having changeable air valve technology, intake and exhaust opening/closing time and lift are all fixing, the port timing of electromotor can not change according to the rotating speed of electromotor, the very difficult job demand with respect to electromotor when different rotating speeds operating mode of this changeless valve stroke.Therefore to meet the job requirement of electromotor full working scope it is necessary to design changeable air valve, promote the power performance of electromotor, make burning more efficiently.For solving foregoing problems, VVL technology and changeable air valve lift technology are arisen at the historic moment.VVL technology can mate suitable valve stroke when electromotor different rotating speeds, different load so that electromotor uses less valve stroke when the slow-speed of revolution, Smaller load, improves cold start-up and reduces oil consumption.Use bigger valve stroke when high rotating speed, big load, reduce valve throttling loss, improve charging efficiency, improve the electromotor power output when high rotating speed, big load and the fuel oil consumption of electromotor can be reduced, improving fuel economy, reduce the discharge of HC, NOx.

Lift range variable technology is to utilize the cam of two kinds of different molded line to control the electromotor valve stroke when high speed operation state and tick-over state respectively in the prior art, the camshaft structure adopted in patent documentation " two-stage is adjustable variable gas distribution " publication number CN201220616883, this patented technology is cased with cam sleeve outside camshaft, camshaft is connected with cam sleeve two ends spline, and stop collar is enclosed within outside cam sleeve；Lower speed cam is fixing with High speed cam to be connected and connects as one with cam sleeve, and the two ends of cam sleeve arrange oppositely oriented spiral grooves, and groove push rod is placed in spiral grooves, and control to switch Lower speed cam High speed cam by electromagnetic actuator.Above technology adopts groove push rod and spiral grooves to realize the switching of High speed cam and Lower speed cam, its handoff procedure impacts bigger, when handoff procedure terminates, its speed and acceleration are all not zero, require over groove trough rim and block push rod, and VVL camshaft structure belongs to precise part, processing cost is high, and it is easily damaged in impact process.

Summary of the invention

The technical problem to be solved is to provide a kind of simple in construction; electromotor can be avoided to produce to impact in the process that high speed operation state and tick-over state switch mutually; can effectively protect camshaft parts, it is possible to be greatly prolonged the VVL camshaft structure in machine components service life.

This invention address that the VVL camshaft structure that its technical problem adopts, including mandrel and cam pack, described cam pack is set on mandrel, described mandrel is provided with hole, location, described cam pack includes high low speed cam set and axle journal, often organize high low speed cam set to be made up of a High speed cam and a Lower speed cam, two groups of height low speed cam set match, described axle journal is between same a pair height speed cam set, also include locating slot, described locating slot is arranged on the both sides of cam pack, described locating slot is made up of high speed locating slot and low speed locating slot, described location is provided with elastic component in hole, the two ends of elastic component are provided with steel ball, when electromotor is in high speed operation state, the steel ball part at elastic component two ends is arranged in high speed locating slot, another part is arranged in hole, location；When electromotor is in tick-over state, the steel ball part at elastic component two ends is arranged in low speed locating slot, and another part is arranged in hole, location, also includes extremity piece, and described extremity piece is arranged on the both sides of cam pack.

Further, described extremity piece being additionally provided with radial cams, described axial end cam and radial cams are compounded on extremity piece.

Further, the rate curve of described axial end cam is connected in sequence by the initial segment, accelerating sections, high speed changeover portion, braking section and ending segment, and speed when axial end cam lift terminates and acceleration equal zero.

Further, speed and acceleration when described radial cams lift terminates are zero.

Further, described cam pack includes two pairs of high low speed cam set, is provided with spacer between described two pairs of high low speed cam set.

Further, also including intermediate pin, two the axial end cams being positioned at two groups of adjacent sides of cam pack are driven by the intermediate pin contacted with two, this side axial end cam simultaneously.

Further, described intermediate pin is flat pin.

Further, described intermediate pin is elliptic pin.

Further, described intermediate pin is double-pin.

Further, the detecting device for detecting intermediate pin radial position is also included.

The invention has the beneficial effects as follows: the application adopts edge cam to carry out driving cam assembly and moves relative to mandrel, owing to the shape of edge cam can be designed according to the requirement that cam pack moves axially, it is made to axially move according to the characteristics of motion that satisfied impact is little by driving cam assembly, therefore the application camshaft structure can realize high speed operation smooth conversion, make high Lower speed cam quick in transformation process, accurately and impact little, significantly reduce the high low speed conversion infringement to machine components, substantially increase the ruggedness of VVL camshaft, extend its service life.

Accompanying drawing explanation

Fig. 1 is the lifting curve figure of edge cam；

Fig. 2 is the speed curve diagram of edge cam；

Fig. 3 is the acceleration plots of edge cam；

Fig. 4 is the lifting curve figure of radial cams；

Fig. 5 is the speed curve diagram of radial cams；

Fig. 6 is the acceleration plots of radial cams；

Fig. 7 is cam pack of the present invention is the structural representation of Split type structure；

Fig. 8 is the structural representation that the present invention adopts two one group of form of cylinder；

Parts, position and numbering in figure: mandrel 1, axle journal 2, high low speed cam set 3, High speed cam 4, Lower speed cam 5, location hole 6, high speed locating slot 8, low speed locating slot 9, steel ball 10, elastic component 11, extremity piece 12, spacer 14, the initial segment 15, accelerating sections 16, high speed changeover portion 17, braking section 18, ending segment 19.

Detailed description of the invention

Below in conjunction with accompanying drawing, the invention will be further described.

nullEmbodiment 1: as shown in Figure 7，VVL camshaft structure in the present embodiment，Including mandrel 1 and cam pack，Cam pack is set on mandrel 1，Described mandrel 1 is provided with hole 6, location，Described cam pack includes high low speed cam set 3 and axle journal 2，Often organize high low speed cam set 3 to be made up of a High speed cam 4 and a Lower speed cam 5，Two groups of height low speed cam set 3 match，Described axle journal 2 is between same a pair height speed cam set 3，Also include locating slot，Described locating slot is arranged on the both sides of cam pack，Described locating slot is made up of high speed locating slot 8 and low speed locating slot 9，Hole, described location 6 is provided with elastic component 11，The two ends of elastic component 11 are provided with steel ball 10，When electromotor is in high speed operation state，Steel ball 10 part at elastic component 11 two ends is arranged in high speed locating slot 8，Another part is arranged in hole 6, location；When electromotor is in tick-over state, steel ball 10 part at elastic component 11 two ends is arranged in low speed locating slot 9, and another part is arranged in hole 6, location, also includes extremity piece 12, and described extremity piece 12 is arranged on the both sides of cam pack.When electromotor needs conversion between high speed operation state and tick-over state, solenoid-driven push rod or pin enter into and the position of axial end cam contact, now axial end cam push rod in rotation process promotes axial edge cam to move axially as requested, axial end cam drives cam pack to move axially again, to realize the switching of high low speed duty.Owing to the shape of edge cam is determined by its lifting curve, and lifting curve also determines the movement law of cam pack, therefore can design the shape of edge cam according to the requirement that cam pack moves.The application is conducive to cam pack steadily to move in handoff procedure after adopting edge cam transmission, effectively prevent it and engine component is impacted.

Embodiment 2: in the present embodiment, described extremity piece 12 is additionally provided with radial cams, described axial end cam and radial cams are compounded on extremity piece 12, being arranged on the radial cams on extremity piece 12 and can make the push rod by solenoid-driven or pin steadily turnover extremity piece 12, the extremity piece 12 of this example can adopt the mode of powder metallurgy to manufacture.

Embodiment 3: adopt the lifting curve of preferred axial end cam to improve stationarity when camshaft duty switches further in the present embodiment.

As in figure 2 it is shown, the rate curve of axial end cam is connected in sequence by the initial segment 15, accelerating sections 16, high speed changeover portion 17, braking section 18 and ending segment 19, and speed when axial end cam lift terminates and acceleration equal zero.Adopting aforementioned rate curve to divide can make cam pack first accelerate to certain speed gently when lift starts in the initial segment 15, the speed that fast speed increases further is added after entering accelerating sections 16, when speed advances into high speed changeover portion 17 close to peak value, the speed of reducing speed change in high speed changeover portion 17, make cam pack speed by accelerating to deceleration smooth transition, the speed that fast speed reduces is added after entering braking section 18, it is made after being comparatively fast reduced to the speed of setting, to enter ending segment 19, at the speed that ending segment 19 reducing speed reduces, its speed is made steadily to be decreased to zero.Corresponding lifting curve and accelerating curve are as shown in figures 1 and 3.

As further improvement, more smoothly passing in and out extremity piece 12 to make push rod steadily pass in and out extremity piece 12, speed and acceleration when radial cams lift terminates are zero.Can adopting the cam lifting curve shown in Fig. 4 when being embodied as, corresponding rate curve and accelerating curve are as shown in Figure 5 and Figure 6.

Embodiment 4: as shown in Figure 8, in the present embodiment, cam pack includes two pairs of high low speed cam set 3, is provided with spacer 14 between two pairs of high low speed cam set 3.Due to a cylinder of the corresponding electromotor of high a pair low speed cam set 3, the present embodiment using two to high low speed cam set 3 as one group, two cylinders of electromotor first corresponding with it form the form of one group of both one group of two cylinder.Between two pairs of high low speed cam set 3, spacer 14 is set, eliminate embodiment 1 edge cam between two pairs of high low speed cam set 3 as shown in Figure 1, also save electromagnetic valve and the push rod at this place simultaneously, make electromagnetic valve be reduced to original four by original eight.

Embodiment 5: also include intermediate pin in the present embodiment, two the axial end cams being positioned at two groups of adjacent sides of cam pack are driven by the intermediate pin contacted with two, this side axial end cam simultaneously.The present embodiment improves further on the basis of embodiment 4, two the axial end cams employings being positioned at two groups of cam pack adjacents are promoted by the pin of same solenoid-driven, can reduce so again by an electromagnetic valve, as shown in Figure 8, for the electromotor of four cylinders, corresponding two groups of cam packs, i.e. four pairs of high low speed cam set 3 on its VVL camshaft structure, if adopting the structure in embodiment 1 to need eight electromagnetic valves, and the present embodiment having only to three electromagnetic valves.

Embodiment 6: adopt flat pin to simultaneously drive two axial end cams in centre position in the present embodiment.Make the two ends of flat pin simultaneously with two axial end cam contact.

Embodiment: 7: adopting described pin in the present embodiment is elliptic pin, simultaneously drives two axial end cams in centre position.

Embodiment 8: adopt the structure of double-pin to realize simultaneously driving middle two axial end cams with an electromagnetic valve in the present embodiment.

Embodiment 9: add the detecting device for detecting intermediate pin radial position in the present embodiment.The present embodiment only checks intermediate pin radial position, it is not necessary to check the position of both sides pin, judges whether intermediate pin enters correctly into or exit extremity piece 12 by the detection that middle pins position is put.

Claims

null1.VVL camshaft structure，Including mandrel (1) and cam pack，Described cam pack is set on mandrel (1)，It is characterized in that: described mandrel (1) is provided with hole, location (6)，Described cam pack includes high low speed cam set (3) and axle journal (2)，Often organize high low speed cam set (3) to be made up of a High speed cam (4) and a Lower speed cam (5)，Two groups of height low speed cam set (3) match，Described axle journal (2) is positioned at between a pair height speed cam set (3)，Also include locating slot，Described locating slot is arranged on the both sides of cam pack，Described locating slot is made up of high speed locating slot (8) and low speed locating slot (9)，Hole, described location (6) is provided with elastic component (11)，The two ends of elastic component (11) are provided with steel ball (10)，When electromotor is in high speed operation state，Steel ball (10) part at elastic component (11) two ends is arranged in high speed locating slot (8)，Another part is arranged in hole, location (6)；When electromotor is in tick-over state, steel ball (10) part at elastic component (11) two ends is arranged in low speed locating slot (9), another part is arranged in hole, location (6), also include extremity piece (12), described extremity piece (12) is arranged on the both sides of cam pack, and described extremity piece is provided with axial end cam on (12).
2. VVL camshaft structure as claimed in claim 1, it is characterised in that: being additionally provided with radial cams on described extremity piece (12), described axial end cam and radial cams are compounded on extremity piece (12).
3. VVL camshaft structure as claimed in claim 1, it is characterized in that: the rate curve of described axial end cam is connected in sequence by the initial segment (15), accelerating sections (16), high speed changeover portion (17), braking section (18) and ending segment (19), and speed when axial end cam lift terminates and acceleration equal zero.
4. VVL camshaft structure as claimed in claim 3, it is characterised in that: speed and acceleration when described radial cams lift terminates are zero.
5. VVL camshaft structure as claimed in claim 1, it is characterised in that: described cam pack includes two pairs of high low speed cam set (3), is provided with spacer (14) between described two pairs of high low speed cam set (3).
6. VVL camshaft structure as claimed in claim 5, it is characterised in that: also including intermediate pin, two the axial end cams being positioned at two groups of adjacent sides of cam pack are driven by the intermediate pin contacted with two, this side axial end cam simultaneously.
7. VVL camshaft structure as claimed in claim 6, it is characterised in that: described intermediate pin is flat pin.
8. VVL camshaft structure as claimed in claim 6, it is characterised in that: described intermediate pin is elliptic pin.
9. VVL camshaft structure as claimed in claim 6, it is characterised in that: described intermediate pin is double-pin.
10. VVL camshaft structure as claimed in claim 6, it is characterised in that: also include the detecting device for detecting intermediate pin radial position.