CN102674043B - A variable speed paper feeding mechanism - Google Patents

Abstract

The invention discloses a variable speed paper feed mechanism and a fixed groove cam plate thereof. The mechanism comprises a power input shaft, a planetary swing arm, a planetary gear swing arm, a first intermediate shaft, a cam roller, a first transmission gear, the fixed groove cam plate and a paper feed line tape roller, wherein the planetary swing arm is fixed on the power input shaft; the left end of the planetary swing arm is hinged with the planetary gear swing arm; the right end of the planetary gear swing arm is meshed with the first transmission gear fixed on the first intermediate shaft; the left end of the planetary gear swing arm and the cam roller are meshed in a cam groove of the fixed groove cam plate; and the first intermediate shaft is fixed on the fixed groove cam plate and drives the paper feed line tape roller to rotate. The mechanism can achieve that the paper has constant speed operation sections in the period of motion so as to improve the paper skip stability during joint of a paper receiving roller and a paper transferring suction nozzle mechanism while achieving the aim of variable speed paper feed and has simple mechanical structure.

Description

A variable speed paper feeding mechanism

technical field

The invention relates to the field of printing, in particular to a variable-speed paper feeding mechanism and a fixed groove cam plate thereof. the

Background technique

As the speed of the sheet-fed printing machine continues to increase, the conveying speed of the paper on the feeder table of the paper feeder is also continuously increased. Before each sheet of paper enters the printing unit, it must be accurately positioned by the front gauge and side gauge to ensure accurate overprinting. The front edge of the paper needs to directly lean against the stationary front positioning plate during motion to complete the circumferential positioning of the printed sheet. Therefore, when the conveying speed of the paper is too high, it is very easy to cause faults such as curling of the paper edge and paper rebound when the paper is in contact with the previous positioning plate for positioning, which affects the normal operation of printing. In order to solve this problem, modern high-speed sheet-fed printing machines generally adopt a variable speed paper feeding mechanism, so that the paper still travels a distance of a paper feeding step in each working cycle, that is, the average speed remains unchanged, but in this The operating speed within a cycle is not constant. In this way, the paper runs at a high speed when it is away from the previous positioning plate, and changes to a low speed when it is about to touch the previous positioning plate. Since the average speed in the whole cycle remains unchanged, the paper feeding speed can meet the requirements of high-speed printing , and can prevent the paper from malfunctioning during positioning. At present, the variable speed paper feeding mechanism used in modern high-speed printing machines mainly includes: rotating guide rod variable speed paper feeding mechanism, non-circular gear variable speed paper feeding mechanism, gear-link combination variable speed paper feeding mechanism and cam-link gear combination variable speed paper feeding mechanism. the

In recent years, the traditional non-circular gear variable speed paper feeding mechanism has been improved, and two kinds of damping and compensation mechanisms have been designed to overcome the vibration during high-speed operation and improve the stability of paper feeding. As shown in Figure 1, the gear linkage variable speed paper feeding mechanism was analyzed and studied, and a motion analysis model based on the matrix method was given. Combined with the paper feeding process, an optimal design model for the design of the variable speed paper feeding mechanism was established and analyzed. Calculation instance. the

Although the several variable speed paper feeding mechanisms introduced above have practical applications and some structural improvements in recent years, they still have some shortcomings. The variable speed paper feeding mechanism must be equipped with a compensation mechanism to reduce vibration, which makes the mechanism more complicated. The variable speed paper feeding mechanism cannot realize the constant speed running section of the paper in the movement cycle to improve the efficiency when the paper receiving roller and the paper delivery nozzle mechanism are handed over. Paper feeding stability. the

Contents of the invention

In view of this, the purpose of the present invention is to propose a variable speed paper feeding mechanism and its fixed groove cam plate, which can realize the purpose of variable speed paper feeding and at the same time realize that the paper has a constant speed running section in the movement cycle to improve the speed of the paper receiving roller and the conveying roller. The stability of paper feeding when the paper suction nozzle mechanism is handed over, and the mechanical structure is simple. the

Based on the above purpose, the variable speed paper feeding mechanism provided by the present invention includes a power input shaft, a planetary swing arm, a planetary gear swing arm, a first intermediate shaft, a cam roller, a first transmission gear, a fixed groove cam plate and a paper conveyor belt roller ;

The planetary swing arm is fixed to the power input shaft, and the left end of the planetary swing arm is hinged to the planetary gear swing arm; the right end of the planetary gear swing arm is fixed to the first intermediate shaft through The first transmission gear on the upper meshes, the left end of the swing arm of the planetary gear and the cam roller mesh in the cam groove of the fixed groove cam plate; the first intermediate shaft is fixed on the The grooved cam plate is fixed, and the first intermediate shaft drives the belt roller of the paper conveying line to rotate. the

Optionally, the left end of the planetary swing arm is connected to the planetary gear swing arm through a pin. the

Optionally, the left end of the swing arm of the planetary gear is engaged with the cam groove of the fixed groove cam plate through the pin shaft and the cam roller. the

Optionally, the cam plate of the fixing groove is fixed to the wall plate through studs. the

Optionally, the power input shaft is axially fixed to the wallboard. the

Optionally, the belt roller of the paper conveying line is axially fixed to the wallboard. the

Optionally, the variable speed paper feeding mechanism includes a second intermediate shaft, the first intermediate shaft is connected to the second intermediate shaft through the meshing of two transmission gears, and at the same time, the second intermediate shaft is connected to the paper feeding The tape roll is connected by the meshing of two transmission gears. the

Optionally, the second intermediate shaft is axially fixed on the cam plate of the fixing groove. the

Optionally, the bottom end of the second intermediate shaft is axially fixed to the wallboard. the

Optionally, the planetary swing arm includes a counterweight processed integrally with the planetary swing arm. the

Based on the above purpose, the present invention also provides a fixed groove cam plate based on a variable speed paper feeding mechanism, including a fixed groove, and the cam profile of the fixed groove is based on the above variable speed paper feeding mechanism, according to the variable speed rotation curve of the first transmission gear , obtained by the method based on the principle of conjugate surfaces. the

Optionally, the shifting rotation curve of the first transmission gear is obtained by using a B-spline curve. the

Optionally, the actual inner contour of the cam contour of the fixed groove is

$\left\{\begin{array}{c}{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; f</span>}}\mathrm{<span\; class="notranslate">\; cos</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; u</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; \&beta;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; \&theta;</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; r</span>}}\mathrm{<span\; class="notranslate">\; sin</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; \&beta;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; \&theta;</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; a</span>}\mathrm{<span\; class="notranslate">\; cos</span>}\mathrm{<span\; class="notranslate">\; \&theta;</span>}\\ {\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; f</span>}}\mathrm{<span\; class="notranslate">\; sin</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; u</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; \&beta;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; \&theta;</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; r</span>}}\mathrm{<span\; class="notranslate">\; cos</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; \&beta;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; \&theta;</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; a</span>}\mathrm{<span\; class="notranslate">\; sin</span>}\mathrm{<span\; class="notranslate">\; \&theta;</span>}\end{array}\right.$

Among them, _Rf is the radius of the cam roller, _β1 is the angular displacement of the planetary gear swing arm, _Lr is the length of the planetary cam swing arm, a is the length of the planetary swing arm, and θ is the rotation angle of the planetary swing arm;

Among them, η is the angle that the planetary gear rotates around its center.

Optionally, the actual outer contour of the cam contour of the fixing groove is an equidistant curve with a distance of 2R _f from the actual inner contour.

It can be seen from the above that the present invention provides a variable-speed paper feeding mechanism and its fixed groove cam plate, which uses a cam-controlled planetary gear train mechanism to realize periodic variable-speed rotation of the paper-feeding line belt roller, thereby realizing variable-speed paper feeding. the goal of. By rationally designing the profile of the cam, on the premise of realizing the variable speed function of the variable speed paper feeding mechanism, the paper can be kept moving at a constant speed in a certain period of time in one cycle, thereby improving the stability of the paper transfer. the

Description of drawings

Fig. 1 is the schematic diagram of the kinematic analysis model of the gear-connecting rod combined variable speed paper feeding mechanism in the prior art;

Fig. 2 is the assembly schematic diagram of the variable speed paper feeding mechanism of the embodiment of the present invention;

Fig. 3 is the schematic diagram of the principle of variable speed movement of the variable speed paper feeding mechanism of the embodiment of the present invention;

Fig. 4 is the schematic diagram of the variable speed motion analysis of the variable speed paper feeding mechanism of the embodiment of the present invention;

Fig. 5 is a schematic flow chart of a method for designing a fixed groove cam profile based on a variable speed paper feeding mechanism according to an embodiment of the present invention;

Fig. 6 is the schematic diagram of the speed change rotation curve of the first transmission gear of the embodiment of the present invention;

Fig. 7 is the schematic diagram of the speed law curve of the cam follower of the embodiment of the present invention;

Fig. 8 is the displacement curve schematic diagram of cam follower of the embodiment of the present invention;

Fig. 9 is a schematic diagram of the angular displacement curve of the first transmission gear of the embodiment of the present invention;

Fig. 10 is a schematic diagram of a transformation mechanism based on the principle of inversion method according to an embodiment of the present invention;

Figure 11 is a schematic diagram of the profile curve of the fixed groove cam of the variable speed paper feeder in the embodiment of the present invention;

Fig. 12 is a screenshot of the two-dimensional motion simulation of the variable speed paper feeding mechanism of the embodiment of the present invention. the

Detailed ways

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be described in further detail below in conjunction with specific embodiments and with reference to the accompanying drawings. the

Referring to Figure 2, it is a schematic diagram of the assembly of the variable speed paper feeding mechanism according to the embodiment of the present invention. Child 7, the first transmission gear 9, the fixed groove cam plate 13 and the belt roller 26 of the paper feeding line. the

In the embodiment of the present invention, the planetary swing arm 4 is fixed to the power input shaft 1, and the left end of the planetary swing arm 4 is hinged to the planetary gear swing arm 6; the planetary gear swing arm 6 right end By meshing with the first transmission gear 9 fixed on the first intermediate shaft 10, the left end of the planetary gear swing arm 6 and the cam roller 7 mesh with the fixed groove cam plate 13 The first intermediate shaft 10 is fixed on the cam plate 13 of the fixed groove, and the first intermediate shaft 10 drives the belt roller 26 to rotate. the

The variable speed paper feeding mechanism also includes a large pin shaft 5 and a small pin shaft, the left end of the planetary swing arm 4 is connected to the planetary gear swing arm 6 through the large pin shaft 5, and the planetary gear swing The left end of the arm 6 is engaged in the cam groove of the fixed groove cam plate 13 through the small pin shaft and the cam roller 7 . the

When the variable speed paper feeding mechanism is working, the planetary swing arm 4 rotates at a constant speed along with the power input shaft 1, and then drives the planetary gear swing arm 6 to swing; because the left end of the planetary gear swing arm 6 passes through the small pin and the The above-mentioned cam roller 7 is engaged in the cam groove of the fixed groove cam plate 13, so the planetary gear swing arm 6 is also controlled by the fixed groove cam plate 13, and finally the right end of the planetary gear swing arm 6 is meshed The first transmission gear 9 drives the first intermediate shaft 10 to rotate at a variable speed; the first intermediate shaft 10 drives the belt roller 26 of the paper conveying line to rotate at a variable speed. the

Wherein, the first intermediate shaft 10 is axially fixed on the fixed groove cam plate 13, and the installation method adopted is: the fixed groove cam plate 13 is processed with holes, and there are two identical Rolling bearing 18, and there are two identical bearing end caps 17 on the upper part; the lower part of the rolling bearing 18 is positioned by the shoulder on the first intermediate shaft 10, and the upper part of the rolling bearing 18 is supported by the bearing end cap 17; The two identical bearing end caps 17 are respectively provided with connecting screws 16 , and the connecting screws 16 are embedded in the cam plate 13 of the fixing groove. Preferably, a shaft sleeve 2 is installed between the first intermediate shaft 10 and the fixed groove cam plate 13, mainly to reduce the loss of components. the

Preferably, the variable speed paper feeding mechanism includes a first connecting stud 8 and a second connecting stud 21, and the fixed groove cam plate 13 passes through the first connecting double studs respectively arranged on its left and right sides. The head stud 8 and the second connecting stud 21 are fixed on the wallboard 22 . the

Wherein, the power input shaft 1 is axially fixed on the wallboard 22 through rolling bearings, bearing end caps and connecting screws. The paper conveyor belt roller 26 is axially fixed on the wallboard 22 by means of a bearing end cover 23 , a connecting screw 24 and a rolling bearing 25 . the

It should also be pointed out that the variable speed paper feeding mechanism also includes a second intermediate shaft 15, the second intermediate shaft 15 is provided with a third transmission gear 14, and the third transmission gear 14 is connected to the The second transfer gear 12 on the first countershaft 10 meshes. The second intermediate shaft 15 is axially fixed on the fixed groove cam plate 13 by the same installation means as the first intermediate shaft 10 . the

The second intermediate shaft 15 is also provided with a fourth transmission gear 19, the fourth transmission gear 19 meshes with the fifth transmission gear 20, and the fifth transmission gear 20 is installed on the paper conveying line On the belt roller 26. Preferably, the bottom end of the second intermediate shaft 15 is axially fixed on the wallboard 22 . the

It can be seen that the first intermediate shaft 10 drives the second intermediate shaft 15 to rotate at a variable speed through the engagement of the second transmission gear 12 and the third transmission gear 14; then, through the fourth transmission gear 19, The meshing effect of the fifth transmission gear 20 makes the said paper conveying line belt roller 26 do variable speed rotation output. the

It is worth noting that the planetary swing arm 4 has taken into account the dynamic balance requirements in its structural design, and is provided with a counterweight, which can be fixed on the planetary swing arm 4 alone, or can be processed with the planetary swing arm 4 An integral structure, in this embodiment, adopts the latter. the

Referring to shown in Fig. 3, it is a schematic diagram of the principle of variable speed movement of the variable speed paper feeding mechanism in the embodiment of the present invention, wherein the planetary swing arm 4 is the original moving part in Fig. The combined effect of the sub 7 and the fixed groove cam plate 13 will make the first transmission gear 9 rotate at a periodic speed change, and the output angular velocity of the first transmission gear 9 is ω _s . The sprockets coaxial with the paper conveyor belt roller 26 and the first transmission gear 9 respectively have the same diameter, and are connected by a chain at the same time. It also performs variable speed rotation, so that the paper has a periodically changing paper feeding speed when it is conveyed, expressed by V _f .

It should be noted that, in FIG. 3 , the belt roller 26 of the paper conveying line is driven to rotate at a variable speed through a chain transmission. In this embodiment, gear transmission is preferably used. The use of gear transmission can improve the stability of the transmission, which is suitable for the needs of high-speed movement. the

Referring to shown in Figure 4, it is a schematic diagram of the speed change motion analysis of the variable speed paper feeding mechanism of the embodiment of the present invention, wherein O _s , _Op , O _f are respectively the centers of the first transmission gear 9, the planetary gear and the cam roller 7; Z _s and Z _p is the number of teeth of the first transmission gear 9 and the planetary gear respectively, and the modulus is m; the center distance between the first transmission gear 9 and the planetary gear is the planetary swing arm 4, and its length is a=0.5(Z _s +Z _p ); the center distance between the planetary gear and the cam roller 7 is the planetary cam swing arm 6, and its length is L _r .

If the connecting line between the center O _s of the first transmission gear 9 and the center O _f of the cam roller 7 is r, then according to the law of cosines, there must be:

${\mathrm{<span\; class="notranslate">\; r</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; a</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; r</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; aL</span>}}_{\mathrm{<span\; class="notranslate">\; r</span>}}\mathrm{<span\; class="notranslate">\; cos</span>}\mathrm{<span\; class="notranslate">\; \&delta;</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$

Among them, δ—the angle between the connecting line O _{f Op} and the connecting line O _{s Op} .

Obviously, in the whole rotation period, the length of r is constantly changing, while the lengths of the planetary swing arm 4 and the planetary cam swing arm 6 remain constant. In order to ensure the certainty of the movement of the mechanism, it must be ensured that L _r +a>r is established in the entire revolution cycle.

It can be seen from this that when the initial position E is set, the meshing point P between the first transmission gear 9 and the planetary gear is located on the X-axis, then when the planetary swing arm 4 rotates counterclockwise through the angle θ, the cam roller 7 will rotate to F position. Considering that the movement among the components in the mechanism is linear, the movement of the mechanism can be decomposed according to the principle of motion superposition, and it is assumed that they move successively. The specific description is as follows: First, assuming that the first transmission gear 9 and the planetary gear are fixed on the planetary swing arm 4, and the constraint imposed by the fixed cam on the planetary gear is temporarily removed, then when the planetary swing arm 4 rotates through the angle θ, the first Transmission gear 9 and planetary gear also will forward to F ' position therewith. Secondly, assuming that the planetary swing arm 4 is fixed at the current position, the first transmission gear 9 and the planetary gears can rotate freely around their respective centers, and the planetary cam swing arm 6 will be forced to rotate due to the restraint of the fixed groove cam plate 13 on the planetary cam swing arm 6. The gear rotates about its present center _Op through an angle η (negative value when oscillating clockwise), thereby causing the cam roller to move from position F' to its actual position F. At the same time, due to the meshing effect of the planetary gear and the first transmission gear 9, the first transmission gear 9 will be rotated through the angle ξ around its center _Os , and at the E position, the first transmission gear 9 and the planetary gear will overlap Points will go to _Ps and _Pp respectively.

According to the previous analysis and description, it can be seen that when the planetary swing arm 4 rotates through the θ angle, the actual displacements of the first transmission gear 9 and the planetary gear are respectively:

_θp = θ+η (2)

θ _s =θ+ξ

Where θ _P - the angular displacement of the planetary gear;

θ _s — the angular displacement of the first transmission gear 9;

According to the transmission relationship of the external gear, there must be

$\mathrm{<span\; class="notranslate">\; \&xi;</span>}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; -</span>\frac{{\mathrm{<span\; class="notranslate">\; z</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}}{{\mathrm{<span\; class="notranslate">\; z</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}}\mathrm{<span\; class="notranslate">\; \&eta;</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; )</span>$

Substituting formula (3) into formula (2) and sorting out, we can get

${\mathrm{<span\; class="notranslate">\; \&theta;</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; \&theta;</span>}<span\; class="notranslate">\; -</span>\frac{{\mathrm{<span\; class="notranslate">\; z</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}}{{\mathrm{<span\; class="notranslate">\; z</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}}\mathrm{<span\; class="notranslate">\; \&eta;</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}<span\; class="notranslate">\; )</span>$

Calculating the first and second derivatives of formula (4) with respect to time can be obtained

${\mathrm{<span\; class="notranslate">\; \&omega;</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; \&omega;</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>\frac{{\mathrm{<span\; class="notranslate">\; z</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}}{{\mathrm{<span\; class="notranslate">\; z</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}}<span\; class="notranslate">\; \&CenterDot;</span>\frac{\mathrm{<span\; class="notranslate">\; d\&eta;</span>}}{\mathrm{<span\; class="notranslate">\; d\&theta;</span>}}<span\; class="notranslate">\; )</span>$

（5）

${\mathrm{<span\; class="notranslate">\; \&epsiv;</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; \&omega;</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}\frac{{\mathrm{<span\; class="notranslate">\; z</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}}{{\mathrm{<span\; class="notranslate">\; z</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}}<span\; class="notranslate">\; \&CenterDot;</span>\frac{{\mathrm{<span\; class="notranslate">\; d</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}\mathrm{<span\; class="notranslate">\; \&eta;</span>}}{{\mathrm{<span\; class="notranslate">\; d\&theta;</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}$

In the formula, ω _s —the angular velocity of the first transmission gear 9;

ε _s — the angular acceleration of the first transmission gear 9;

ω—the angular velocity of the planetary swing arm 4;

Obviously, from the above analysis, the angle η is determined by the contour curve of the fixed groove cam plate 13 in the mechanism. Therefore, designing different cam profiles as required can control the output motion of the first transmission gear 9 . the

More importantly, the present invention proposes a fixed groove cam plate based on the above-mentioned variable speed paper feeding mechanism. As shown in Figure 2, the fixed groove cam plate 13 includes a fixed groove, and the cam profile of the fixed groove The line is obtained according to the shifting rotation curve of the first transmission gear 9 by a method based on the principle of conjugate surfaces. the

Referring to Fig. 5, it is a schematic flow chart of the method for designing the fixed groove cam contour based on the variable speed paper feeding mechanism according to the embodiment of the present invention, including:

Step 501, according to the variable speed paper feeding mechanism of the present invention, perform periodic variable speed rotation, and calculate the variable speed rotation curve of the first transmission gear, the specific implementation process is as follows:

1) The variable speed paper feeding mechanism of the embodiment of the present invention performs periodic variable speed rotation, please refer to Figure 6, which is a schematic diagram of the variable speed rotation curve of the first transmission gear in the embodiment of the present invention: the horizontal axis represents the rotation angle of the cam driving member, The vertical axis represents the angular velocity of the first transmission gear 9 . the

According to the formula (5), the fixed groove cam plate 13 will control the reciprocating swing of the planetary gear in one rotation cycle. Therefore, the average angular velocity of the first transmission gear 9 in one cycle is:

${\stackrel{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; \&omega;</span>}}}_{\mathrm{<span\; class="notranslate">\; 5</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; \&omega;</span>}$

It can be seen from this that the paper will move forward the same distance in each cycle, that is, one paper feeding step. And the paper feeding speed at any moment in the cycle is:

${\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; f</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}}{\mathrm{<span\; class="notranslate">\; 1000</span>}\mathrm{<span\; class="notranslate">\; T</span>}}\frac{{\mathrm{<span\; class="notranslate">\; \&omega;</span>}}_{\mathrm{<span\; class="notranslate">\; 5</span>}}}{{\mathrm{<span\; class="notranslate">\; \&omega;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 6</span>}<span\; class="notranslate">\; )</span>$

Among them, s ₀ —the paper feeding step distance of the paper feeder;

T - the printing cycle of the printing press. the

From the above analysis, it can be seen that if the change rule V _f (θ) of the speed change motion required for conveying paper is determined according to the printing process conditions, the motion rule of the first transmission gear 9 can be deduced. The following will be described in conjunction with specific examples.

Assume that the printing speed of a sheet-fed offset printing machine is 18,000 sheets/hour, that is, the angular velocity of the planetary swing arm 4 of the prime mover is ω=10πrad/s, and the printing cycle is T=0.2s. If the paper feeding step of the paper feeder is 205mm, the average speed of paper feeding is For the convenience of design, the deceleration coefficient τ is specially defined, then the maximum and minimum values of the angular velocity of the first transmission gear 9 can be expressed as:

ω _5max ＝ω(1+τ)

ω _5max ＝ω(1-τ) (7)

The value of the deceleration coefficient τ depends on the specific process conditions, generally 15% to 30%. The value of the deceleration coefficient should not be too large, otherwise the maximum paper feeding speed will be too large and the paper feeding will be unstable. In this example, taking τ=0.2, it can be known from formula (7) and formula (6), that the extreme value of the angular velocity of the first transmission gear 9 and the extreme value of the paper feeding speed are respectively

ω _5max =12π rad/s, V _fmax =1.23m/s

(8)

ω _5min =8π rad/s, V _fmin =0.82m/s

In order to ensure the stability of paper feeding and paper transfer, the paper will maintain the same time period at the highest paper feeding speed and the lowest paper feeding speed respectively during the entire movement cycle, that is, there are two constant speed running segments with the same time length. Through reasonable arrangement, the paper runs at the lowest running speed when it collides with the previous positioning plate, and completes the handover of the paper receiving roller and the paper delivery nozzle in the high-speed constant speed section, improving the stability of paper feeding. the

The angular velocity curve of the first transmission gear 9 required by the splicing place according to known conditions and technological requirements of numerical speed change, i.e. the speed change rotation curve of the first transmission gear, each section is arranged as follows:

In the first stage, θ is from 0° to 160°, the angular velocity of the first transmission gear 9 changes from ω _5min to the maximum value ω _5max , and when θ=80°, ω _s =ω=10π rad/s;

In the second section, θ is from 160° to 180°, and the first transmission gear 9 keeps rotating at a constant speed of ω _5max ;

In the third stage, θ is from 180° to 340°, the angular velocity of the first transmission gear 9 is reduced from ω _5max to the minimum value ω _5min , and when θ=260°, ω _s =ω=10π rad/s;

In the fourth segment, θ is from 340° to 360°, and the first transmission gear 9 keeps rotating at a constant speed of ω _5min .

Among them, the first section of angular velocity curve adopts B-spline curve, and the following boundary conditions can be given according to the known conditions

When θ=0°, ω ₅ =ω _5min , ε=0, jerk=0;

When θ=80°, ω ₅ =10πrad/s;

When θ=160°, ω ₅ =ω _5max , ε=0, jerk=0;

There are 7 boundary conditions in total, and the order of B-spline is k=5, then the steps of solving the cam curve are analogous to B-spline curve, and the relevant parameters can be taken as:

tau=[0,0,0,80,160,160,160]

m=[0,1,2,0,0,1,2]

(9)

T=[0,40,120,160]

F=[ω _5min ,0,0,10π,ω _5max ,0,0]

In the formula, tau—the angular position corresponding to the boundary condition;

Types of motion constraints for each angular position described in m—tau, 0 represents displacement constraints, 1 represents velocity constraints, 2 represents acceleration constraints, and 3 represents jerk constraints;

The node sequence of the T-B spline curve, where the first point and the end point are repeated k times, in this example, k=5 times;

F—constraint value corresponding to each boundary constraint. the

The second and fourth sections are simple constant-velocity rotation curve sections without design. The third section of the curve still adopts B-spline, and according to the known conditions, its boundary condition is

When θ=180°, ω ₅ =ω _5max , ε=0, jerk=0;

When θ=260°, ω ₅ =10π rad/s;

When θ=340°, ω ₅ =ω _5min , ε=0, jerk=0;

Still take the order of the B-spline curve as k=5, then the relevant parameters of the third segment of the B-spline curve are set to

tau=[180,180,180,260,340,340,340]

m=[0,1,2,0,0,1,2] (10)

T=[180,220,300,340]

F=[ω _5max ,0,0,10π,ω _5min ,0,0]

According to the parameter settings in Equation (9) and Equation (10), the automatic solution program is called to obtain the curves of each segment respectively, and after splicing, the graph of ω ₅ can be obtained, that is, the speed change rotation curve of the first transmission gear 9 .

It should be noted that, in order to facilitate the subsequent design of the cam profile, the graph shown in FIG. 6 is obtained by using the position of θ=260° in the original splicing graph as the starting point of the motion. the

Step 502, obtain the speed change law curve of the cam follower according to the speed change rotation curve of the first transmission gear The speed law curve of the cam follower is integrated to θ, and the displacement curve η of the cam follower is obtained; the speed change rotation curve of the first transmission gear is integrated to time t, and the variation law of the rotation angle θ of the first transmission gear ₉ in the mechanism is obtained Curve; the specific implementation process is as follows:

1) According to the speed change rotation curve of the first transmission gear 9, it is calculated The law of change, that is, the law of motion of the follower of the cam: From the speed change rotation curve of the first transmission gear 9 obtained in step 501, according to formula (5), it can be calculated as change rule. That is, the speed law curve of the cam follower can be obtained. Please refer to FIG. 7 , which is a schematic diagram of the speed law curve of the cam follower according to the embodiment of the present invention. Wherein, the horizontal axis represents the rotation angle of the cam prime mover, and the vertical axis represents the speed of the cam follower.

2) The speed law curve of the cam follower is integrated with θ to obtain the angular displacement of the cam roller, that is, the change law curve of η. Please refer to FIG. 8, which is a schematic diagram of the displacement curve of the cam follower according to the embodiment of the present invention. Wherein, the horizontal axis is the rotation angle of the cam driving member, and the vertical axis is the angle η that the planetary gear rotates around its current center O _p .

3) The speed change rotation curve of the first transmission gear is integrated with time t, and the change law curve of the rotation angle _θ5 of the first transmission gear 9 in the mechanism can be obtained. Please refer to FIG. 9, which is the first transmission gear of the embodiment of the present invention Schematic diagram of the angular displacement curve.

Step 503, according to n and The change law curve of the curve and the calculation method based on the conjugate surface principle are used to obtain the profile curve of the fixed groove cam that meets the speed change requirements. The specific implementation process is as follows:

1) According to η and The change law curve of the curve and the calculation method based on the principle of conjugate surface can be used to obtain the profile curve of the fixed groove cam that meets the speed change requirements.

In this embodiment, in order to design the fixed cam in this mechanism, the principle of the inversion method is adopted, that is, assuming that a common -ω is applied to the whole mechanism, as shown in Figure 10, which is the embodiment of the present invention based on inversion Schematic diagram of the transformation mechanism of the law principle. In this conversion mechanism, the planetary swing arm 4 becomes fixed, and the cam will rotate clockwise at an angular velocity of ω, thereby pushing the planetary gear swing arm 6 to rotate around its center on a fixed axis, and the original planetary gear and the first transmission gear 9 Constitute an ordinary fixed axle gear train. The design of the cam profile in this transformation mechanism is calculated using the design formula based on the theory of conjugate surfaces. the

First establish the coordinate system shown in Figure 10, wherein the origin O and O of the _fixed coordinate system σ and the moving coordinate system σ ₂ fixedly connected with the cam coincide with the center O _s of the first transmission gear 9, and the planetary gear swing arm 6 The origin of the fixed moving coordinate system σ ₁ coincides with the center O _p of the planetary gear.

The cam rotation angle θ ₂ in the conversion mechanism, the angular displacement β ₁ of the planetary gear swing arm 6 and the relevant angles in the original mechanism shown in Fig. 4 have the following corresponding relationship:

θ ₂ =-θ

β ₁ =-(β ₁₀ +η)

In the above formula, the initial swing angle of the planetary gear swing arm 6 can be obtained by the following formula

${\mathrm{<span\; class="notranslate">\; \&beta;</span>}}_{\mathrm{<span\; class="notranslate">\; 10</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; \&delta;</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; -</span>\frac{\mathrm{<span\; class="notranslate">\; \&pi;</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}}$

Assuming that the radius of the base circle on the actual profile of the cam is R _b , and the radius of the cam roller is R _f , then it can be seen from formula (1) that the initial position angle δ ₀ can be obtained by the following formula

${\mathrm{<span\; class="notranslate">\; \&delta;</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; arccos</span>}<span\; class="notranslate">\; (</span>\frac{{\mathrm{<span\; class="notranslate">\; a</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; r</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; b</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; f</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; aL</span>}}_{\mathrm{<span\; class="notranslate">\; r</span>}}}<span\; class="notranslate">\; )</span>$

Accordingly, the actual inner profile equation of the cam can be obtained as

$\left\{\begin{array}{c}{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; f</span>}}\mathrm{<span\; class="notranslate">\; cos</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; u</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; \&beta;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; \&theta;</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; r</span>}}\mathrm{<span\; class="notranslate">\; sin</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; \&beta;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; \&theta;</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; a</span>}\mathrm{<span\; class="notranslate">\; cos</span>}\mathrm{<span\; class="notranslate">\; \&theta;</span>}\\ {\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; f</span>}}\mathrm{<span\; class="notranslate">\; sin</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; u</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; \&beta;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; \&theta;</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; r</span>}}\mathrm{<span\; class="notranslate">\; cos</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; \&beta;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; \&theta;</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; a</span>}\mathrm{<span\; class="notranslate">\; sin</span>}\mathrm{<span\; class="notranslate">\; \&theta;</span>}\end{array}\right.<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 11</span>}<span\; class="notranslate">\; )</span>$

in, $u=\mathrm{arctg}\left(\frac{a\sin {\mathrm{\&beta;}}_1-L_r(1+\frac{\mathrm{d\&eta;}}{\mathrm{d\&theta;}})}{-a\cos {\mathrm{\&beta;}}_1}\right).$

Similarly, it can be known that the pressure angle of the cam mechanism is

α=180-|u|

In formula (11), let R _f =0 to get the theoretical profile equation of the cam. The solution method of the actual profile equation in which the grooved cam is located outside the theoretical profile is discussed below. Since the outer contour of the cam and its inner contour are equidistant curves with a distance of 2R _f , the method for solving the equation of the inner contour of the cam can be completely compared. That is, first obtain the coordinate expression of the point on the roller that coincides with the point on the outer contour of the cam in the follower moving coordinate system σ ₁ , and then convert it to the cam coordinate system σ ₂ by means of homogeneous coordinate transformation The desired cam profile equation can be obtained. As shown in Figure 6-8, assuming that in the coordinate system σ ₁ , the coordinates of the point on the roller that is in contact with the actual outer contour of the cam is (x′ ₁ , y′ ₁ ), then there must be

$\left\{\begin{array}{c}{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; f</span>}}\mathrm{<span\; class="notranslate">\; cos</span>}\mathrm{<span\; class="notranslate">\; \&alpha;</span>}\\ {\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; f</span>}}\mathrm{<span\; class="notranslate">\; sin</span>}\mathrm{<span\; class="notranslate">\; \&alpha;</span>}\end{array}\right.$

The above formula can be organized as

$\left\{\begin{array}{c}{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; f</span>}}\mathrm{<span\; class="notranslate">\; cos</span>}\mathrm{<span\; class="notranslate">\; u</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 2</span>}{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; f</span>}}\mathrm{<span\; class="notranslate">\; cos</span>}\mathrm{<span\; class="notranslate">\; \&alpha;</span>}\\ {\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; r</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; f</span>}}\mathrm{<span\; class="notranslate">\; sin</span>}\mathrm{<span\; class="notranslate">\; u</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; f</span>}}\mathrm{<span\; class="notranslate">\; sin</span>}\mathrm{<span\; class="notranslate">\; \&alpha;</span>}\end{array}\right.$

According to the principle of homogeneous coordinate transformation, the point is transformed into the cam coordinate system σ ₂ and sorted out, the actual contour equation of the cam can be obtained

$\left\{\begin{array}{c}{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}^{<span\; class="notranslate">\; \&prime;</span>}\mathrm{<span\; class="notranslate">\; cos</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; \&beta;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; \&theta;</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}^{<span\; class="notranslate">\; \&prime;</span>}\mathrm{<span\; class="notranslate">\; sin</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; \&beta;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; \&theta;</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; a</span>}\mathrm{<span\; class="notranslate">\; cos</span>}\mathrm{<span\; class="notranslate">\; \&theta;</span>}\\ {\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}^{<span\; class="notranslate">\; \&prime;</span>}\mathrm{<span\; class="notranslate">\; sin</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; \&beta;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; \&theta;</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}^{<span\; class="notranslate">\; \&prime;</span>}\mathrm{<span\; class="notranslate">\; cos</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; \&beta;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; \&theta;</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; a</span>}\mathrm{<span\; class="notranslate">\; sin</span>}\mathrm{<span\; class="notranslate">\; \&theta;</span>}\end{array}\right.$

Obviously, the method described above can be used to solve any curve equation equidistant from the actual inner profile of the cam. the

In this embodiment, the number of teeth of the planetary gear and the first transmission gear is respectively 20 and 40, the modulus of the number of teeth is m=2, the length of the swing arm 6 of the planetary gear is _Lr =35mm, and the radius of the cam roller is R _f =10mm, and the radius of the base circle of the actual inner contour is R _b =60mm. According to the automatic calculation and simulation program compiled by the above known conditions, the cam contour diagram is obtained. Fig. 11 is a schematic diagram of the contour curve of the fixed groove cam of the variable speed paper feeder of the embodiment of the present invention, and Fig. 12 is the variable speed paper feed mechanism of the embodiment of the present invention A screenshot of the 2D motion simulation.

A variable-speed paper feeding mechanism and its fixed groove cam plate proposed by the present invention creatively adopt a cam-controlled planetary gear train mechanism to realize the periodic variable-speed rotation of the paper-feeding line belt roller, thereby realizing the purpose of variable-speed paper feeding. Reasonable design of the profile of the cam can keep the paper moving at a constant speed during certain periods of a cycle under the premise of realizing the speed change function of the variable speed paper feeding mechanism, thereby improving the stability of paper transfer. the

Those of ordinary skill in the art should understand that: the above descriptions are only specific embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present invention etc., should be included within the protection scope of the present invention. the

Claims (10)

1. a speed change paper feed mechanism, is characterized in that, comprises power input shaft, planet swing arm, planetary wheel swing arm, the first tween drive shaft, cam roller, the first transmission gear, hold down groove lobe plate and defeated paper yarn band roller;

Power input shaft is fixed in described planet swing arm, and the left part of described planet swing arm and described planetary wheel swing arm hinged; Described planetary wheel swing arm right-hand member is by engaging with described the first transmission gear being fixed on the first tween drive shaft, and described planetary wheel swing arm left end and described cam roller are engaged in the cam path of described hold down groove lobe plate; Described the first tween drive shaft is fixed on described hold down groove lobe plate, and described the first tween drive shaft drives described defeated paper yarn band roller to rotate;

Wherein, described hold down groove lobe plate comprises hold down groove, and the cam profile of described hold down groove is to rotate curve according to the speed change of the first transmission gear, adopts the method based on conjugate curved surface principle to obtain; It is to have adopted B-spline curves to obtain that the speed change of the first described transmission gear is rotated curve;

The actual internal profile of the cam profile of described hold down groove is

$\left\{\begin{array}{c}{x}_2=R_f\cos (u+{\mathrm{\&beta;}}_1+\mathrm{\&theta;})-L_r\sin ({\mathrm{\&beta;}}_1+\mathrm{\&theta;})+a\cos \mathrm{\&theta;}\\ y_2=R_f\sin (u+{\mathrm{\&beta;}}_1+\mathrm{\&theta;})+L_r\cos ({\mathrm{\&beta;}}_1+\mathrm{\&theta;})+a\sin \mathrm{\&theta;}\end{array}\right.$

Wherein, R _ffor roller radius of cam mechanism, β ₁for the angular transposition of planetary wheel swing arm, L _rfor the length of planetary cam swing arm, a is the length of planet swing arm, and θ is the angle that planet swing arm is rotated;

wherein, η is the angle that planetary wheel Rao Qi center turns over;

The actual profile of the cam profile of described hold down groove is to be 2R with actual internal profile distance _fequidistant curve.

2. mechanism according to claim 1, is characterized in that, described planet swing arm left part joins by bearing pin and described planetary wheel swing arm.

3. mechanism according to claim 2, is characterized in that, described planetary wheel swing arm left end is engaged in the cam path of described hold down groove lobe plate by bearing pin and described cam roller.

4. mechanism according to claim 1, is characterized in that, described hold down groove lobe plate is fixed on wallboard by double end stud.

5. mechanism according to claim 4, is characterized in that, described power input shaft is axially fixed at wallboard.

6. mechanism according to claim 4, is characterized in that, described defeated paper yarn band roller is axially fixed at wallboard.

7. mechanism according to claim 1, it is characterized in that, described speed change paper feed mechanism comprises the second tween drive shaft, described the first tween drive shaft is connected by engaging of two transmission gears with described the second tween drive shaft, and described the second tween drive shaft is connected by engaging of two transmission gears with described defeated paper yarn band roller simultaneously.

8. mechanism according to claim 7, is characterized in that, the second described tween drive shaft is axially fixed on described hold down groove lobe plate.

9. mechanism according to claim 8, is characterized in that, the second described tween drive shaft bottom is axially fixed at wallboard.

10. according to the mechanism described in claim 1 to 9 any one, it is characterized in that, described planet swing arm comprises the clump weight being processed as one with planet swing arm.