CN101158296A - A camshaft-mounted gas distribution mechanism for a motorcycle engine - Google Patents

Abstract

The utility model relates to a camshaft-mounted gas distribution mechanism of a motorcycle engine. It includes a camshaft, intake and exhaust ejector rods, intake and exhaust rocker arms and intake and exhaust valves. There is an intake cam and an exhaust cam on the camshaft among the present invention. The intake and exhaust cams respectively push the intake and exhaust push rods through the disc-shaped flat-bottomed intake tappets and exhaust tappets. The axes of the intake and exhaust tappets are all orthogonal to the axis of the camshaft. The cam profiles of the intake and exhaust cams are respectively formed by connecting nine smooth transitional line segments from the beginning to the end. Therefore, the air intake and exhaust of the present invention have higher timing accuracy, better continuity in the intake and exhaust process, and will not cause sudden changes in inertial force; the driven part has good force transmission performance and high transmission efficiency. Both the power and torque of the engine can be increased by 10% to 13%, and the noise can be reduced by about 10dB.

Description

A camshaft-mounted gas distribution mechanism for a motorcycle engine

technical field

The invention relates to a gas distribution mechanism of a motorcycle engine, in particular to a camshaft-mounted gas distribution mechanism.

Background technique

There are two types of valve trains for motorcycle engines: upper camshaft and lower camshaft. The former engine is commonly called the camshaft-mounted engine, and the latter is commonly called the camshaft-mounted engine (also known as the CG series engine). The former has a relatively simple structure, and it directly pushes the intake and exhaust rocker arms respectively through the intake and exhaust cams on the camshaft to achieve air distribution to the engine cylinders. However, since the upper camshaft is far away from the crankshaft, the driving force must be obtained from the lower crankshaft through a chain drive, so the timing of the gas distribution is poor, resulting in low power, torque and efficiency of the engine . The latter gets the driving force from the crankshaft directly through the gear transmission. But because this camshaft is far away from intake and exhaust rocker arm again, so, must transmit between camshaft and intake and exhaust rocker arm by other parts. The gas distribution mechanism of the existing camshaft-mounted engine consists of a camshaft with only one cam; an intake and exhaust rocker arm that is installed on both sides of the cam and promoted by the same cam; One intake and exhaust ejector rod pushed by each arm; one intake and exhaust rocker arm pushed respectively by the intake and exhaust ejector rods, and the inlet and exhaust rocker arms respectively driven by the intake and exhaust rocker arms and equipped with return springs. , Exhaust valve composition. Compared with the two types of engines manufactured by manufacturers with the same equipment and technology level, the CG series engines are better in terms of valve timing. Therefore, this type of CG series engine is adopted in more and more motorcycles. However, because only one shared cam is designed on the camshaft of the existing CG series engines, two sets of transmission mechanisms and the intake and exhaust rocker arms are simultaneously driven by the same cam to realize the adjustment of the intake and exhaust valves. On and off. From the perspective of design rules and requirements, the intake cam mechanism is a reverse design, while the exhaust cam mechanism is a same-direction design. Under the condition that the design parameters of the intake and exhaust cam mechanisms are the same, the designed two cam profiles should be different. In the case of sharing a cam, either the contour lines of the two cannot meet the design requirements, or the contour line of one of them is sacrificed-at present, most of them are designed according to the intake cam mechanism, that is, the reverse type design, and the exhaust The cam is replaced by the intake cam, so that the opening and closing of the intake and exhaust valves cannot be controlled according to the regular movement during the intake and exhaust process, and the expected timing gas distribution cannot be realized. As a result, the power, torque and even efficiency of the existing CG series engines are still low; the gas distribution noise is also difficult to control.

Contents of the invention

The first purpose of the present invention is to provide a camshaft-mounted gas distribution mechanism of a motorcycle engine that can ensure that the intake and exhaust processes are designed in accordance with the law of motion, in view of the deficiencies in the prior art.

The second object of the present invention is to provide a transmission mechanism with good force transmission performance and good lubricating conditions for the valve mechanism on the basis of realizing the first object.

The third object of the present invention is, on the basis of realizing the second object, to provide the gas distribution mechanism with an intake and exhaust cam which has neither rigid impact nor flexible impact and low gas distribution noise.

In order to realize the purpose of the first invention, the technical solution provided by the present invention is such a camshaft-mounted valve train of a motorcycle engine. The same aspect of the gas distribution mechanism as the prior art is: it includes a camshaft with a cam on it, and finally the intake and exhaust ejector pins are driven by the cam, and the intake and exhaust ejector pins respectively pass through the ball hinges at the upper ends respectively. The intake and exhaust rocker arms are connected to one end and pushed to swing, and the intake and exhaust rocker arms respectively conflict with their tail ends through the adjustment screws on the other ends and push them to open the intake and exhaust valves; Each return spring that drives them to close is respectively installed on the door. Its improvement is that there are two cams on the camshaft in the present invention, and they are respectively an intake cam and an exhaust cam that can be designed independently. The intake cam and the exhaust cam push the intake and exhaust ejector rods respectively by moving the intake tappet and the exhaust tappet of the driven rod type—the upper ends of the intake tappet and the exhaust tappet They are connected to each other through a ball joint at the lower end of the intake and exhaust push rods respectively.

In order to realize the object of the second invention, in the solution for realizing the object of the first invention, the intake tappet and the exhaust tappet used are all disk-shaped flat-bottomed tappets whose bottom surfaces are perpendicular to their respective axes, and the intake tappet And the axis of exhaust tappet all is orthogonal with the axis of camshaft of the present invention again.

In order to realize the object of the third invention, in the solution for realizing the object of the second invention, the cam profiles of the intake cam and the exhaust cam are respectively formed by connecting nine smooth transitional line segments from the beginning to the end. They are in order: ①thrust sine correction section, ②thrust uniform speed correction section, ③thrust sine main curve section, ④thrust cosine main curve section, ⑤return cosine main curve section, ⑥return sine main curve section, ⑦return Constant speed correction section, ⑧return sine correction section, ⑨arc section corresponding to base circle near-stop angle.

The process of the present invention to control the opening and closing of the intake and exhaust valves is the same as that of the prior art, and will not be described in detail. In addition to retaining the prior art, ball joints are arranged on the intake and exhaust ejector rods, and the main and follower parts at both ends are connected through ball joint hinges to eliminate the advantages of over-constraint. Compared with the prior art, the present invention has the following advantages.

As can be seen from the scheme of realizing the purpose of the first invention, because the present invention replaces the shared cam of the intake and exhaust in the prior art with the intake cam and the exhaust cam, so people can fully follow the intake cam and the exhaust cam. The corresponding cams on the camshafts of the CG series engines were designed according to the movement law of the exhaust process, and then the timing requirements of the intake and exhaust of the series engines were truly met.

As can be seen from the additional solution for realizing the purpose of the second invention, because the intake tappet and the exhaust tappet in the present invention are moving driven rods with a disc-shaped flat bottom. In this way, not only the problem that the intake and exhaust swing arms in the prior art are worn between the rotating shaft hole and the rotating shaft and affect the transmission accuracy will not occur, but also the two cams correspond to the intake and exhaust respectively. It is also easy to form between the bottom surfaces of the tappets and can keep the lubricating oil film, thereby reducing the gas distribution noise and improving the transmission efficiency. Because the intake tappet and the exhaust tappet are disc-shaped flat-bottomed axes, the axis is orthogonal to the axis of the camshaft of the present invention, that is: the transmission angle of the two cams and the corresponding flat-bottomed follower is 90 °, and the force transmission performance Well, the transmission efficiency is high.

As can be seen from the additional scheme of realizing the third invention object, since the cam profiles of the intake cam of the present invention and the exhaust cam are respectively connected by nine sections of smooth and transitional line segments (the specific line shapes of each section will be described in Further disclosure in the detailed description). In this way, it is ensured that the valve mechanism has sufficient air intake, clean exhaust, high inflation efficiency, and further reduces air distribution noise. The cam in the valve train adopts segmented function to combine the cams, which can ensure the continuity of the movement of the intake and exhaust process, and the acceleration curve is continuous, so it will not cause a sudden change in the inertial force.

Among them, the reason for adopting a sinusoidal curve with no sudden change in acceleration at the start point of the push stroke and the end point of the return stroke is to avoid the instantaneous impact generated during high-speed operation. The uniform speed linear section is used as the buffer section to make the intake and exhaust valves move at a constant speed when opening and closing, and effectively control the valve opening and seating speed, further reducing the gas distribution noise. The main curve adopts multi-segment composite function profile, which can obtain a higher charge coefficient. The smooth connection of each section of the profile line satisfies the displacement of each section of the curve at the connection, the velocity and acceleration are continuous, and there is neither rigid shock nor flexible shock.

In addition, the present invention has the advantages of simple structure, convenient processing and easy guarantee of processing accuracy.

The present invention will be further described below in conjunction with the accompanying drawings.

Description of drawings

Fig. 1 - structural representation of the present invention

Figure 2 - Left view of Figure 1

Figure 3 - the structural diagram of the inlet (exhaust) gas ejector rod in Figure 1

Figure 4 - Partial enlarged view of area I in Figure 3

Figure 5 - the structural diagram of the intake (exhaust) gas tappet in Figure 1

Figure 6 - the assembly diagram of the intake and exhaust cams of the present invention

Fig. 7 - schematic diagram of the lift curve of the follower in the cam mechanism of the present invention

In Fig. 1, E ₁ and E ₂ are the contact points between the intake and exhaust valves and the adjustment screws respectively, B ₁ and B ₂ are the centers of the ball joints connecting the intake and exhaust ejector pins with the respective corresponding rocker arms, A ₁ , A ₂ are respectively the center of the ball joint connecting the intake and exhaust tappets with the respective corresponding ejector rods, and D ₁ , D ₂ are the contact lines between the intake and exhaust cams and the bottom surfaces of the corresponding tappets respectively.

In Fig. 6, the installation angle Φ is the angle between the installation marking line and the maximum radial direction of the exhaust cam.

Detailed ways

Disclosed is a camshaft-mounted valve train of a motorcycle engine (refer to Figs. 1-5). The gas distribution mechanism includes a camshaft with a cam on it, finally the intake and exhaust push rods (7, 8) pushed by the cam, and the intake and exhaust push rods (7, 8) respectively pass through the ball joints at the upper ends respectively. The intake and exhaust rocker arms (2, 3) that are connected to one end and push it to swing, the intake and exhaust rocker arms (2, 3) respectively conflict with their tail ends through the adjustment screws 5 on the other ends and push them to open Intake and exhaust valves (1, 4) [after adjusting the adjustment screws 5 respectively, the adjustment screws 5 are locked on the end of the intake and exhaust rocker arms (2, 3) by the lock nut 6]. Each back-moving spring (because it is obvious and is the prior art, so omits and does not draw among the figures) is respectively installed with driving them to close on this inlet and exhaust valve (1,4). In the present invention, there are two cams on the camshaft, and they are intake cam 11 and exhaust cam 12 respectively. The intake cam 11 and the exhaust cam 12 push the intake and exhaust push rods (7, 8) by moving the intake tappet 9 and the exhaust tappet 10 of the driven rod type respectively—the intake tappet The upper ends of the post 9 and the exhaust tappet 10 are connected to each other by a ball joint at the lower ends of the intake and exhaust push rods (7, 8).

Further speaking, the intake tappet 9 and the exhaust tappet 10 in the present invention (refer to FIGS. 1 to 5) are all disk-shaped flat-bottomed tappets whose bottom surfaces are perpendicular to their respective axes. The axes of the columns 10 are all perpendicular to the axes of the camshafts.

Further speaking, the cam profiles of the intake cam 11 and the exhaust cam 12 in the present invention (referring to Fig. 7) are respectively formed by connecting the smooth and transitional line segments of nine segments, which are successively: 1. thrust sine correction segment, 2. Thrust constant velocity correction section, ③ thrust sine main curve section, ④ thrust cosine main curve section, ⑤ return cosine main curve section, ⑥ return sine main curve section, ⑦ return constant speed correction section, ⑧ return sine correction section, ⑨ base The arc segment corresponding to the near stop angle of the circle;

Each line segment of the above cam profile is calculated according to the following equation, and the meanings of the symbols are:

variable:

S()——follower lift; V()——first derivative of follower lift;

a()——second derivative of follower lift; ——cam rotation angle;

Known quantity:

Φ ₀ ——The total wrap angle of the cam profile push stroke and return stroke;

S _m — total lift of thrust;

S ₁ ——lift of correction section of thrust; S ₃ ——lift of correction section of return stroke;

β ₁ ——wrap angle of thrust correction section; β ₃ ——wrap angle of return correction section;

N ₁ — equal fraction of the sinusoidal correction section of the thrust; N ₃ — equal fraction of the sinusoidal correction section of the return trip;

Ψ ₁ ——wrapping angle of the main curve section of the thrust; Ψ ₃ ——wrapping angle of the main curve section of the return trip;

Calculated amount:

q——the ratio of the wrapping angle of the return main curve to the wrapping angle of the lift main curve $q=\frac{{\mathrm{\ψ}}_3}{{\mathrm{\ψ}}_1}$

S _1a ——thrust sine correction section lift $S_{1a}=\frac{{\mathrm{<figure-callout\; id="1"\; label="S"\; filenames="S200710093002XE00011.png,S200710093002XE00021.png"\; state="\{\{state\}\}">S</figure-callout>}}_1}{2N_1-1}$

β _1a ——Inclination angle of thrust sine correction section ${\mathrm{\&beta;}}_{1a}=\frac{{\mathrm{\&beta;}}_1}{{\mathrm{<figure-callout\; id="1"\; label="N"\; filenames="S200710093002XE00011.png,S200710093002XE00021.png"\; state="\{\{state\}\}">N</figure-callout>}}_1}$

S _3a ——lift of return sine correction section $S_{3a}=\frac{{\mathrm{<figure-callout\; id="3"\; label="S"\; filenames="S200710093002XE00011.png,S200710093002XE00031.png"\; state="\{\{state\}\}">S</figure-callout>}}_3}{2N_3-1}$

β _3a ——Inclination angle of thrust sine correction section ${\mathrm{\&beta;}}_{3a}=\frac{{\mathrm{\&beta;}}_3}{{\mathrm{<figure-callout\; id="3"\; label="N"\; filenames="S200710093002XE00011.png,S200710093002XE00031.png"\; state="\{\{state\}\}">N</figure-callout>}}_3}$

S _1b ——Thrust constant speed correction section lift $S_{1b}=\frac{2(N_1-1){\mathrm{<figure-callout\; id="1"\; label="S"\; filenames="S200710093002XE00011.png,S200710093002XE00021.png"\; state="\{\{state\}\}">S</figure-callout>}}_1}{2N_1-1}=2S_{1a}(N_1-1)$

β _1b ——Inclination angle of thrust constant velocity correction section β _1b = β ₁ - β _1a

β _3b ——Inclination angle of thrust constant speed correction section β _3b = β ₃ - β _3a

Ψ ₃ ——Inclination angle of return main curve section Ψ ₃ ＝qΨ ₁

h ₁ ——The lift of the sinusoidal main curve section of the thrust $h_{}$${}_1=\frac{(S_m-S_1)\mathrm{\&pi;}+{\mathrm{<figure-callout\; id="1"\; label="V"\; filenames="S200710093002XE00011.png,S200710093002XE00021.png"\; state="\{\{state\}\}">V</figure-callout>}}_1{\mathrm{\&psi;}}_1}{4+\mathrm{\&pi;}}$

h ₂ ——thrust cosine main curve section lift h ₂ ＝S _m -S ₁ -h ₁

h ₃ ——lift of cosine main curve section of return journey h ₃ ＝4p ² (S _m -S ₁ -h ₁ )

h ₄ ——lift of sinusoidal main curve section of return journey h ₄ ＝S _m -S ₃ -h ₃

Intermediate variables:

${\mathrm{<span\; class="notranslate">\; <figure-callout\; id="1"\; label="V"\; filenames="S200710093002XE00011.png,S200710093002XE00021.png"\; state="\{\{state\}\}">V</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 2</span>}{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}\mathrm{<span\; class="notranslate">\; a</span>}}}{{\mathrm{<span\; class="notranslate">\; \&beta;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}$ ${\mathrm{<span\; class="notranslate">\; <figure-callout\; id="3"\; label="V"\; filenames="S200710093002XE00011.png,S200710093002XE00031.png"\; state="\{\{state\}\}">V</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 2</span>}{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}\mathrm{<span\; class="notranslate">\; a</span>}}}{{\mathrm{<span\; class="notranslate">\; \&beta;</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}}$

$m=-\frac{(q-p){\mathrm{\&psi;}}_1(-{\mathrm{<figure-callout\; id="3"\; label="V"\; filenames="S200710093002XE00011.png,S200710093002XE00031.png"\; state="\{\{state\}\}">V</figure-callout>}}_3+\frac{h_4}{(q-p){\mathrm{\&psi;}}_1})}{\mathrm{\&pi;}}$

Equations of each line segment of the cam profile:

①Thrust sine correction section,

②Thrust constant speed correction section,

a()=0

③Sinusoidal main curve section of thrust,

④The cosine main curve section of the thrust,

⑤ Return cosine principal curve segment, ∈(β ₁ +Ψ ₁ , β ₁ +Ψ ₁ +pΨ ₁ ]

in, $p=\frac{-b+\sqrt{{\mathrm{<figure-callout\; id="2"\; label="b"\; filenames="S200710093002XE00011.png,S200710093002XE00021.png"\; state="\{\{state\}\}">b</figure-callout>}}^2+4\mathrm{ac}}}{2a}$

a=2(4-π)h ₂ , b=2πh ₂ qV ₃ Ψ ₁ , c=-[2(S _m -S ₁ )-V ₃ Ψ ₃ ]

⑥ Return sinusoidal principal curve segment, ∈(β ₁ +Ψ ₁ +pΨ ₁ , β ₁ +Ψ ₁ +qΨ ₁ ]

⑦ Return uniform speed correction section, ∈(β ₁ +Ψ ₁ +qΨ ₁ , Φ ₀ -β ₃ ]

a()=0

⑧Return sine correction section; ∈(Φ ₀ -β ₃ , Φ ₀ ]

⑨The arc segment corresponding to the near-stop angle of the base circle, ∈(Φ ₀ , 2π]

S()＝0 V()＝0 a()＝0.

Next, take the CG150 and CG200 engine motorcycles as examples to introduce the verification results.

1. CG150 motorcycle (refer to Figure 1).

(1) Basic parameters of the mechanism

Intake mechanism:

Base circle radius R _b1 = 14.0mm tappet length $L_{A_{}}$${{}_1{\mathrm{D.}}_1}_{}=50.0\mathrm{mm}$

Ejector length $L_{A_1{\mathrm{<figure-callout\; id="1"\; label="B"\; filenames="S200710093002XE00011.png,S200710093002XE00021.png"\; state="\{\{state\}\}">B</figure-callout>}}_1}=129.5\mathrm{mm}$ Rocker arm length $L_{o_1{\mathrm{<figure-callout\; id="1"\; label="B"\; filenames="S200710093002XE00011.png,S200710093002XE00021.png"\; state="\{\{state\}\}">B</figure-callout>}}_1}=20.0\mathrm{mm}$

tap length $L_{o_{}}$${{}_1{\mathrm{E.}}_1}_{}=32.6\mathrm{mm}$

Vertical distance L _d1 from rocker arm rotation center to valve axis = 32.0mm

Rocker arm angle γ ₁ = 140.0° Valve angle η ₁ = 26.0°

vertical center distance $L_{o_{}}$${{}_1}_{}=200.0\mathrm{mm}$ Horizontal center distance L ₁ =23.0mm

Exhaust mechanism:

Base circle radius R _b2 = 14.0mm tappet length $L_{A_{}}$${{}_2{\mathrm{D.}}_2}_{}=50.0\mathrm{mm}$

Ejector length $L_{A_2{\mathrm{<figure-callout\; id="2"\; label="B"\; filenames="S200710093002XE00011.png,S200710093002XE00021.png"\; state="\{\{state\}\}">B</figure-callout>}}_2}=129.5\mathrm{mm}$ Rocker arm length $L_{o_2{\mathrm{<figure-callout\; id="2"\; label="B"\; filenames="S200710093002XE00011.png,S200710093002XE00021.png"\; state="\{\{state\}\}">B</figure-callout>}}_2}=20.0\mathrm{mm}$

tap length $L_{o_{}}$${{}_2{\mathrm{E.}}_2}_{}=32.6\mathrm{mm}$

Vertical distance L _d2 from rocker arm rotation center to valve axis = 32.0mm

Rocker arm angle γ ₂ = 140.0° Valve angle η ₂ = 29.0°

vertical center distance $L_{o_{}}$${{}_2}_{}=198.8\mathrm{mm}$ Horizontal center distance L ₂ =29.3mm

(2) Cam design parameters

Intake cam:

Push angle Φ ₁₁ = 92.0° Return angle Φ ₃₁ = 106.0°

Maximum displacement S _m1 = 4.85mm

Corrected displacement S ₁₁ =0.15mm Corrected rotation angle β ₁₁ =24.0°

Corrected displacement S ₃₁ =0.2mm Corrected rotation angle β ₃₁ =30.0°

Tappet flat bottom width b ₁ =14.0mm

The lift data calculated according to the above formula are shown in Table 1-1.

Table 1-1 Motorcycle CG150 engine intake cam lift table

corner lift corner lift corner lift corner lift 000 0.00000 050 0.87577 100 4.50362 150 0.48901 001 0.00026 051 0.93678 101 4.41974 151 0.45816 002 0.00164 052 1.00060 102 4.33007 152 0.42935 003 0.00456 053 1.06724 103 4.23557 153 0.40253 004 0.00910 054 1.13672 104 4.13713 154 0.37768 005 0.01507 055 1.20908 105 4.03551 155 0.35474 006 0.02183 056 1.28432 106 3.93140 156 0.33367 007 0.02865 057 1.36247 107 3.82540 157 0.31442 008 0.03547 058 1.44354 108 3.71804 158 0.29692 009 0.04229 059 1.52753 109 3.60979 159 0.28111 010 0.04911 060 1.61445 110 3.50107 160 0.26691 011 0.05593 061 1.70431 111 3.39223 161 0.25421 012 0.06276 062 1.79709 112 3.28360 162 0.24292 013 0.06958 063 1.89280 113 3.17546 163 0.23289 014 0.07640 064 1.99141 114 3.06806 164 0.22396 015 0.08322 065 2.09289 115 2.96161 165 0.21591

016 0.09004 066 2.19722 116 2.85632 166 0.20844 017 0.09686 067 2.30435 117 2.75235 167 0.20116 018 0.10368 068 2.41422 118 2.64985 168 0.19388 019 0.11050 069 2.52676 119 2.54896 169 0.18661 020 0.11732 070 2.64187 120 2.44980 170 0.17933 021 0.12414 071 2.75945 121 2.35246 171 0.17206 022 0.13096 072 2.87936 122 2.25702 172 0.16478 023 0.13778 073 3.00144 123 2.16358 173 0.15750 024 0.14461 074 3.12550 124 2.07219 174 0.15023 025 0.15143 075 3.25130 125 1.98292 175 0.14295 026 0.15826 076 3.37856 126 1.89580 176 0.13568 027 0.16545 077 3.50694 127 1.81088 177 0.12840 028 0.17357 078 3.63602 128 1.72819 178 0.12112 029 0.18297 079 3.76531 129 1.64777 179 0.11385 030 0.19389 080 3.89418 130 1.56963 180 0.10657 031 0.20651 081 4.02186 131 1.49379 181 0.09930 032 0.22098 082 4.14739 132 1.42026 182 0.09202 033 0.23740 083 4.26951 133 1.34905 183 0.08474 034 0.25587 084 4.38657 134 1.28018 184 0.07747 035 0.27647 085 4.49631 135 1.21363 185 0.07019 036 0.29927 086 4.59565 136 1.14941 186 0.06292 037 0.32432 087 4.68058 137 1.08751 187 0.05564 038 0.35170 088 4.74737 138 1.02794 188 0.04837 039 0.38143 089 4.79528 139 0.97067 189 0.04109 040 0.41357 090 4.82669 140 0.91571 190 0.03381 041 0.44817 091 4.84432 141 0.86303 191 0.02654 042 0.48525 092 4.85000 142 0.81262 192 0.01933 043 0.52486 093 4.84438 143 0.76448 193 0.01281 044 0.56704 094 4.82747 144 0.71857 194 0.00752 045 0.61182 095 4.79925 145 0.67489 195 0.00366 046 0.65922 096 4.75989 146 0.63341 196 0.00127 047 0.70929 097 4.70981 147 0.59411 197 0.00019 048 0.76206 098 4.64974 148 0.55696 198 0.00000 049 0.81754 099 4.58065 149 0.52193

198°～360° is the arc segment corresponding to the near-stop angle of the base circle, and the lift is 0.

Exhaust cam:

Push angle Φ ₁₂ = 90.0° Return angle Φ ₃₂ = 106.0°

Maximum displacement S _m2 = 4.50mm

Corrected displacement S ₁₂ =0.15mm Corrected rotation angle β ₁₂ =24.0°

Corrected displacement S ₃₂ =0.20mm Corrected rotation angle β ₃₂ =30.0°

Tappet flat bottom width b ₂ =13.2mm

The lift data calculated according to the above formula are shown in Table 1-2.

Table 1-2 Motorcycle CG150 Engine Exhaust Cam Lift Table

corner lift corner Lift corner lift corner Lift 000 0.00000 050 0.87962 100 4.04284 150 0.42153 001 0.00026 051 0.94081 101 3.95892 151 0.39591 002 0.00164 052 1.00479 102 3.87113 152 0.37214 003 0.00456 053 1.07157 103 3.78015 153 0.35019 004 0.00910 054 1.14117 104 3.68659 154 0.33000 005 0.01507 055 1.21362 105 3.59100 155 0.31153 006 0.02183 056 1.28891 106 3.49385 156 0.29471 007 0.02865 057 1.36708 107 3.39559 157 0.27948 008 0.03547 058 1.44811 108 3.29661 158 0.26576 009 0.04229 059 1.53201 109 3.19725 159 0.25346 010 0.04911 060 1.61878 110 3.09782 160 0.24247 011 0.05593 061 1.70841 111 2.99860 161 0.23266 012 0.06276 062 1.80089 112 2.89983 162 0.22387 013 0.06958 063 1.89619 113 2.80172 163 0.21589 014 0.07640 064 1.99428 114 2.70448 164 0.20844 015 0.08322 065 2.09513 115 2.60828 165 0.20116 016 0.09004 066 2.19867 116 2.51327 166 0.19388 017 0.09686 067 2.30484 117 2.41959 167 0.18661 018 0.10368 068 2.41356 118 2.32735 168 0.17933 019 0.11050 069 2.52472 119 2.23667 169 0.17206 020 0.11732 070 2.63819 120 2.14765 170 0.16478 021 0.12414 071 2.75384 121 2.06035 171 0.15750 022 0.13096 072 2.87146 122 1.97486 172 0.15023 023 0.13778 073 2.99084 123 1.89124 173 0.14295 024 0.14461 074 3.11170 124 1.80954 174 0.13568 025 0.15143 075 3.23373 125 1.72982 175 0.12840 026 0.15826 076 3.35652 126 1.65211 176 0.12112 027 0.16546 077 3.47960 127 1.57644 177 0.11385 028 0.17361 078 3.60234 128 1.50286 178 0.10657 029 0.18305 079 3.72402 129 1.43137 179 0.09930 030 0.19404 080 3.84365 130 1.36200 180 0.09202 031 0.20675 081 3.95999 131 1.29477 181 0.08474 032 0.22132 082 4.07135 132 1.22968 182 0.07747 033 0.23786 083 4.17542 133 1.16674 183 0.07019 034 0.25647 084 4.26895 134 1.10596 184 0.06292 035 0.27723 085 4.34778 135 1.04735 185 0.05564 036 0.30019 086 4.40851 136 0.99089 186 0.04837 037 0.32543 087 4.45139 137 0.93659 187 0.04109 038 0.35299 088 4.47931 138 0.88443 188 0.03381 039 0.38292 089 4.49496 139 0.83442 189 0.02654 040 0.41527 090 4.50000 140 0.78654 190 0.01933 041 0.45007 091 4.49502 141 0.74079 191 0.01281 042 0.48737 092 4.48006 142 0.69714 192 0.00752 043 0.52721 093 4.45521 143 0.65558 193 0.00366 044 0.56961 094 4.42065 144 0.61609 194 0.00127 045 0.61461 095 4.37680 145 0.57867 195 0.00019 046 0.66224 096 4.32424 146 0.54327 196 0.00000 047 0.71253 097 4.26371 147 0.50989 048 0.76550 098 4.19606 148 0.47849 049 0.82119 099 4.12216 149 0.44905

196°～360° is the arc segment corresponding to the near-stop angle of the base circle, and the lift is 0.

(3) Assembly parameters of intake and exhaust cams (refer to Figure 6)

Initial radial angle β＝112.0° Installation angle Φ＝122.0°

Maximum radial angle α＝114.0° Overlap angle δ＝84.0°

The overlap angle refers to the camshaft rotation angle corresponding to the simultaneous opening of the intake and exhaust valves (1, 4).

Two, CG200 type motorcycle (referring to Fig. 1).

(1) Basic parameters of the mechanism

Intake mechanism:

Base circle radius R _b1 = 15.0mm tappet length $L_{A_{}}$${{}_1{\mathrm{D.}}_1}_{}=50.0\mathrm{mm}$

Ejector length $L_{A_1{\mathrm{<figure-callout\; id="1"\; label="B"\; filenames="S200710093002XE00011.png,S200710093002XE00021.png"\; state="\{\{state\}\}">B</figure-callout>}}_1}=135.5\mathrm{mm}$ Rocker arm length $L_{o_1{\mathrm{<figure-callout\; id="1"\; label="B"\; filenames="S200710093002XE00011.png,S200710093002XE00021.png"\; state="\{\{state\}\}">B</figure-callout>}}_1}=20.0\mathrm{mm}$

tap length $L_{o_{}}$${{}_1{\mathrm{E.}}_1}_{}=32.7\mathrm{mm}$

Vertical distance L _d1 from rocker arm rotation center to valve axis = 32.0mm

Rocker arm angle γ ₁ = 141.6° Valve angle η ₁ = 26.0°

vertical center distance $L_{o_{}}$${{}_1}_{}=208.0\mathrm{mm}$ Horizontal center distance L ₁ =23.0mm

Exhaust mechanism:

Base circle radius R _b2 = 15.0mm tappet length $L_{A_{}}$${{}_2{\mathrm{D.}}_2}_{}=50.0\mathrm{mm}$

Ejector length $L_{A_2{\mathrm{<figure-callout\; id="2"\; label="B"\; filenames="S200710093002XE00011.png,S200710093002XE00021.png"\; state="\{\{state\}\}">B</figure-callout>}}_2}=135.5\mathrm{mm}$ Rocker arm length $L_{o_2{\mathrm{<figure-callout\; id="2"\; label="B"\; filenames="S200710093002XE00011.png,S200710093002XE00021.png"\; state="\{\{state\}\}">B</figure-callout>}}_2}=20.0\mathrm{mm}$

tap length $L_{o_{}}$${{}_2{\mathrm{E.}}_2}_{}=32.7\mathrm{mm}$

Vertical distance L _d2 from rocker arm rotation center to valve axis = 32.0mm

Rocker arm angle γ ₂ = 140.5° Valve angle η ₂ = 29.0°

vertical center distance $L_{o_{}}$${{}_2}_{}=206.0\mathrm{mm}$ Horizontal center distance L ₂ =28.0mm

(2) Cam design parameters

Intake cam:

Push angle Φ ₁₁ = 98.0° Return angle Φ ₃₁ = 106.0°

Maximum displacement S _m1 = 5.250mm

Corrected displacement S ₁₁ =0.16mm Corrected rotation angle β ₁₁ =25.000°

Corrected displacement S ₃₁ =0.280mm Corrected rotation angle β ₃₁ =30.000°

Tappet flat bottom width b ₁ =13.8mm

The lift data calculated according to the above formula are shown in Table 2-1.

Table 2-1 Motorcycle CG200 engine intake cam lift table

corner lift corner Lift corner Lift corner lift 000 0.00000 051 0.87541 102 5.16955 153 0.73485 001 0.00019 052 0.93532 103 5.12378 154 0.69343 002 0.00127 053 0.99796 104 5.06790 155 0.65429 003 0.00368 054 1.06336 105 5.00239 156 0.61741 004 0.00757 055 1.13154 106 4.92798 157 0.58276 005 0.01289 056 1.20251 107 4.84558 158 0.55029 006 0.01940 057 1.27628 108 4.75618 159 0.51997 007 0.02648 058 1.35286 109 4.66077 160 0.49175 008 0.03359 059 1.43227 110 4.56031 161 0.46558 009 0.04070 060 1.51451 111 4.45567 162 0.44141 010 0.04782 061 1.59957 112 4.34765 163 0.41917 011 0.05493 062 1.68747 113 4.23697 164 0.39880 012 0.06204 063 1.77818 114 4.12426 165 0.38023 013 0.06916 064 1.87170 115 4.01009 166 0.36334 014 0.07627 065 1.96800 116 3.89496 167 0.34804 015 0.08339 066 2.06707 117 3.77930 168 0.33419 016 0.09050 067 2.16887 118 3.66351 169 0.32162 017 0.09761 068 2.27335 119 3.54793 170 0.31015 018 0.10473 069 2.38046 120 3.43286 171 0.29948 019 0.11184 070 2.49013 121 3.31858 172 0.28923 020 0.11895 071 2.60230 122 3.20532 173 0.27904 021 0.12607 072 2.71687 123 3.09329 174 0.26885 022 0.13318 073 2.83372 124 2.98268 175 0.25866 023 0.14030 074 2.95272 125 2.87365 176 0.24848 024 0.14741 075 3.07373 126 2.76633 177 0.23829 025 0.15452 076 3.19657 127 2.66086 178 0.22810 026 0.16164 077 3.32103 128 2.55735 179 0.21791 027 0.16876 078 3.44686 129 2.45588 180 0.20772 028 0.17623 079 3.57379 130 2.35655 181 0.19753 029 0.18454 080 3.70148 131 2.25941 182 0.18734 030 0.19405 081 3.82955 132 2.16455 183 0.17715 031 0.20499 082 3.95754 133 2.07199 184 0.16696 032, 0.21756 083 4.08493 134 1.98179 185 0.15677 033 0.23189 084 4.21109 135 1.89399 186 0.14658 034 0.24811 085 4.33528 136 1.80861 187 0.13639 035 0.26632 086 4.45664 137 1.72568 188 0.12620 036 0.28659 087 4.57410 138 1.64522 189 0.11601 037 0.30902 088 4.68645 139 1.56723 190 0.10582 038 0.33365 089 4.79221 140 1.49173 191 0.09564 039 0.36054 090 4.88972 141 1.41872 192 0.08545 040 0.38976 091 4.97721 142 1.34820 193 0.07526 041 0.42134 092 5.05307 143 1.28018 194 0.06507 042 0.45533 093 5.11619 144 1.21465 195 0.05488 043 0.49176 094 5.16632 145 1.15160 196 0.04469

044 0.53068 095 5.20393 146 1.09102 197 0.03450 045 0.57212 096 5.22988 147 1.03289 198 0.02475 046 0.61612 097 5.24503 148 0.97721 199 0.01631 047 0.66270 098 5.25000 149 0.92396 200 0.00957 048 0.71189 099 5.24504 150 0.87313 201 0.00469 049 0.76372 100 5.23009 151 0.82467 202 0.00165 050 0.81822 101 5.20498 152 0.77859 203 0.00025 204 0.00000

204°～360° is the arc segment corresponding to the near-stop angle of the base circle, and the lift is 0.

Exhaust cam:

Push angle Φ ₁₂ = 94.0° Return angle Φ ₃₂ = 100.0°

Maximum displacement S _m2 = 4.75mm Corrected displacement S ₁₂ = 0.17mm

Corrected rotation angle β ₁₂ =24.0° β ₁₂ equally divided N ₁₂ =6.0

Corrected displacement S ₃₂ =0.28mm Corrected rotation angle β ₃₂ =30.0°

Flat bottom width b ₂ of tappet = 12.9mm

Lift data table calculated according to the above formula 2-2

Table 2-2 Motorcycle CG200 Engine Exhaust Cam Lift Table

corner Lift corner lift corner Lift corner Lift 000 0.00000 050 0.88761 099 4.61438 148 0.56220 001 0.00029 051 0.94702 100 4.55304 149 0.53010 002 0.00182 052 1.00909 101 4.48107 150 0.50024 003 0.00506 053 1.07384 102 4.39969 151 0.47257 004 0.01010 054 1.14128 103 4.31037 152 0.44705 005 0.01676 055 1.21142 104 4.21452 153 0.42361 006 0.02439 056 1.28426 105 4.11343 154 0.40218 007 0.03212 057 1.35981 106 4.00825 155 0.38269 008 0.03985 058 1.43806 107 3.89995 156 0.36504 009 0.04758 059 1.51902 108 3.78937 157 0.34912 010 0.05531 060 1.60267 109 3.67721 158 0.33480 011 0.06304 061 1.68900 110 3.56409 159 0.32191 012 0.07077 062 1.77798 111 3.45053 160 0.31024 013 0.07850 063 1.86959 112 3.33697 161 0.29949 014 0.08623 064 1.96379 113 3.22380 162 0.28923 015 0.09396 065 2.06055 114 3.11135 163 0.27904 016 0.10169 066 2.15979 115 2.99990 164 0.26885 017 0.10942 067 2.26147 116 2.88970 165 0.25866 018 0.11715 068 2.36549 117 2.78097 166 0.24848 019 0.12488 069 2.47178 118 2.67389 167 0.23829 020 0.13261 070 2.58021 119 2.56862 168 0.22810 021 0.14034 071 2.69065 120 2.46530 169 0.21791 022 0.14807 072 2.80296 121 2.36404 170 0.20772 024 0.16354 073 2.91696 122 2.26494 171 0.19753 025 0.17127 074 3.03244 123 2.16810 172 0.18734 026 0.17900 075 3.14916 124 2.07359 173 0.17715 027 0.18701 076 3.26684 125 1.98145 174 0.16696

028 0.19579 077 3.38515 126 1.89176 175 0.15677 029 0.20572 078 3.50370 127 1.80455 176 0.14658 030 0.21705 079 3.62203 128 1.71985 177 0.13639 031 0.22996 080 3.73963 129 1.63769 178 0.12620 032 0.24460 081 3.85586 130 1.55810 179 0.11601 033 0.26110 082 3.96997 131 1.48108 180 0.10582 034 0.27956 083 4.08107 132 1.40665 181 0.09564 035 0.30006 084 4.18809 133 1.33481 182 0.08545 036 0.32267 085 4.28976 134 1.26556 183 0.07526 037 0.34745 086 4.38460 135 1.19890 184 0.06507 038 0.37447 087 4.47090 136 1.13483 185 0.05488 039 0.40378 088 4.54694 137 1.07334 186 0.04469 040 0.43541 089 4.61122 138 1.01442 187 0.03450 041 0.46942 090 4.66291 139 0.95805 188 0.02475 042 0.50583 091 4.70198 140 0.90421 189 0.01631 043 0.54469 092 4.72903 141 0.85290 190 0.00957 044 0.58602 093 4.74482 142 0.80408 191 0.00469 045 0.62987 094 4.75000 143 0.75774 192 0.00165 046 0.67625 095 4.74482 144 0.71385 193 0.00025 047 0.72519 096 4.72911 145 0.67238 194 0.00000 048 0.77671 097 4.70241 146 0.63330 049 0.83085 098 4.66425 147 0.59659

194°～360° is the arc segment corresponding to the near-stop angle of the base circle, and the lift is 0.

(3) Assembly parameters of intake and exhaust cams (refer to Figure 6)

Initial radial angle β＝108.0° Installation angle Φ＝126.0°

Maximum radial angle α＝112.0° Overlap angle δ＝86.0°

The verification results of the above-mentioned CG150 and CG200 engine motorcycles are shown in Table 3.

table 3

According to the verification results, the power of the motorcycle with the CG series engine of the present invention has been increased by 10% to 13%, and the torque has also been increased by 10% to 13%, while the noise has been reduced by about 10dB. Therefore, its economic and environmental aspects are of greater significance.

Claims (3)

1. a camshaft-mounted gas distribution mechanism of a motorcycle engine, the gas distribution mechanism comprises a camshaft with a cam on it, and finally the intake and exhaust ejector rods (7,8) promoted by the cam, the intake and discharge The air ejector rods (7, 8) are respectively connected with one end of the ball hinges at their upper ends and push the swinging intake and exhaust rocker arms (2, 3), and the intake and exhaust rocker arms (2, 3) pass through their respective The adjusting screw (5) on the other end conflicts with its tail end and promotes the intake and exhaust valves (1,4) of their opening; Root back-moving spring, it is characterized in that, the cam that has on the camshaft is two, and they are intake cam (11) and exhaust cam (12) respectively; This intake cam (11) and exhaust cam ( 12) Push the intake and exhaust ejector pins (7, 8) by moving the driven intake tappet (9) and exhaust tappet (10) respectively, the intake tappet (9) The upper ends of the exhaust tappets (10) are connected to each other by respectively a ball joint at the lower ends of the intake and exhaust push rods (7, 8). 2. according to the camshaft under-mounted type valve mechanism of the described motorcycle engine of claim 1, it is characterized in that, described intake tappet (9) and exhaust tappet (10) all are that its bottom surface is perpendicular to respective axis Disc-shaped flat-bottom tappets, the axes of the intake tappets (9) and the exhaust tappets (10) are all perpendicular to the axis of the camshaft. 3. according to the camshaft under-mounted air distribution mechanism of the described motorcycle engine of claim 2, it is characterized in that, the cam profiles of the intake cam (11) and the exhaust cam (12) are respectively smooth and transitional by nine segments. They are connected by line segments, which are ①thrust sine correction segment, ②thrust constant speed correction segment, ③thrust sine main curve segment, ④thrust cosine main curve segment, ⑤return cosine main curve segment, ⑥return sine main curve segment, ⑦ return uniform speed correction segment, ⑧ return sine correction segment, ⑨ arc segment corresponding to base circle near-stop angle; Each line segment of the above cam profile is calculated according to the following equation, and the meanings of the symbols are: variable: S()——follower lift V()——first derivative of follower lift; a()——second derivative of follower lift ——cam rotation angle; Known quantity: Φ ₀ ——The total wrap angle of the cam profile push stroke and return stroke; S _m — total lift of thrust; S ₁ ——lift of correction section of thrust S ₃ ——lift of correction section of return stroke; β ₁ ——wrap angle of thrust correction section; β ₃ ——wrap angle of return correction section; N ₁ — equal fraction of the sinusoidal correction section of the thrust; N ₃ — equal fraction of the sinusoidal correction section of the return trip; Ψ ₁ ——wrapping angle of the main curve section of the thrust; Ψ ₃ ——wrapping angle of the main curve section of the return trip; Calculated amount: q——the ratio of the wrapping angle of the return main curve to the wrapping angle of the lift main curve $q=\frac{{\mathrm{\&psi;}}_3}{{\mathrm{\&psi;}}_1}$ S _1a ——thrust sine correction section lift $S_{1a}=\frac{S_1}{2N_1-1}$ β _1a ——Inclination angle of thrust sine correction section ${\mathrm{\&beta;}}_{1a}=\frac{{\mathrm{\&beta;}}_1}{N_1}$ S _3a ——lift of return sine correction section $S_{3a}=\frac{S_3}{2N_3-1}$ β _3a ——Inclination angle of thrust sine correction section ${\mathrm{\&beta;}}_{3a}=\frac{{\mathrm{\&beta;}}_3}{N_3}$ S _1b ——Thrust constant speed correction section lift $S_{1b}=\frac{2(N_1-1)S_1}{2N_1-1}=2S_{1a}(N_1-1)$ β _1b ——Inclination angle of thrust constant velocity correction section β _1b = β ₁ - β _1a β _3b ——Inclination angle of thrust constant speed correction section β _3b = β ₃ - β _3a Ψ ₃ ——Inclination angle of return main curve section Ψ ₃ ＝qΨ ₁ h ₁ ——The lift of the sinusoidal main curve section of the thrust $h_1=\frac{(S_m-S_1)\mathrm{\&pi;}+V_1{\mathrm{\&psi;}}_1}{4+\mathrm{\&pi;}}$ h ₂ ——thrust cosine main curve section lift h ₂ ＝S _m -S ₁ -h ₁ h ₃ ——lift of cosine main curve section of return journey h ₃ ＝4p ² (S _m -S ₁ -h ₁ ) h ₄ ——lift of sinusoidal main curve section of return journey h ₄ ＝S _m -S ₃ -h ₃ Intermediate variables: ${\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 2</span>}{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}\mathrm{<span\; class="notranslate">\; a</span>}}}{{\mathrm{<span\; class="notranslate">\; \&beta;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}$ ${\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 2</span>}{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}\mathrm{<span\; class="notranslate">\; a</span>}}}{{\mathrm{<span\; class="notranslate">\; \&beta;</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}}$ $m=-\frac{(q-p){\mathrm{\&psi;}}_1(-V_3+\frac{h_4}{(q-p){\mathrm{\&psi;}}_1})}{\mathrm{\&pi;}}$ Equations of each line segment of the cam profile: ①Thrust sine correction section,

②Thrust constant speed correction section,

a()=0 ③Sinusoidal main curve section of thrust,

④The cosine main curve section of the thrust,

⑤ Return cosine principal curve segment, ∈(β ₁ +Ψ ₁ , β ₁ +Ψ ₁ +pΨ ₁ ]

in, $p=\frac{-b+\sqrt{b^2-4\mathrm{ac}}}{2a}$ a=2(4-π)h ₂ , b=2πh ₂ qV ₃ Ψ ₁ , c=-[2(S _m -S ₁ )-V ₃ Ψ ₃ ] ⑥ Return sinusoidal principal curve segment, ∈(β ₁ +Ψ ₁ +pΨ ₁ , β ₁ +Ψ ₁ +qΨ ₁ ]

⑦ Return uniform speed correction section, ∈(β ₁ +Ψ ₁ +qΨ ₁ , Φ ₀ -β ₃ ]

a()=0 ⑧Return sine correction section; ∈(Φ ₀ -β ₃ , Φ ₀ ]

⑨The arc segment corresponding to the near-stop angle of the base circle, ∈(Φ ₀ , 2π] S()＝0 V()＝0 a()＝0.

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