CN104332096A - Direct-acting follower cam-gear train combination teaching aid - Google Patents

Abstract

The invention discloses a direct-acting follower cam-gear train combination teaching aid. The motion rules of different direct-acting followers of a cam mechanism, a counter-rotating method of the cam mechanism, and the conversion frame principle of transmission ratio calculation in an epicyclic gear train are difficult reaching points, yet most students cannot completely understand principles and basic knowledge points. The teaching aid comprises a general support, a driving conversion device, a driving wheel train mechanism, a planetary gear train mechanism and a cam assembly. The driving conversion device manually or electrically drives the driving wheel train mechanism and the planetary gear train mechanism; and the motion and the counter-rotating method of the cam assembly are realized through the planetary gear train mechanism. According to the invention, the motion rules of the different direct-acting followers of the cam mechanism can be demonstrated, the head shapes of the different direct-acting followers can be converted, eccentricity can be adjusted, basic circles and theoretical profiles are extensible, the cam tuning angle is readable, the motion displacement of the direct-acting followers is readable, the motion rules are displayed, the counter-rotating methods of the cam mechanism of the direct-acting followers and the knowledge point of the conversion frame principle of the transmission ratio calculation of the epicyclic gear train can be demonstrated.

Description

Direct follower cam-wheel train combination teaching aid

technical field

The invention belongs to the field of teaching aids, and in particular relates to a direct-acting follower cam-wheel train combination teaching aid.

Background technique

"Mechanical Principles" is a basic course for mechanical majors. It has strong theoretical and practical aspects. Whether students learn it well will directly affect future design and practice. The knowledge points of the motion laws of different direct-acting followers of the cam mechanism, the reversal method of the cam mechanism, and the transformation frame principle of the calculation of the transmission ratio in the epicyclic gear train are difficult points in the teaching. In the teaching process, the teacher uses multimedia means to explain with animation, However, most students cannot fully understand the principles and basic knowledge points. Students seem to understand but do not understand, and the teaching effect is not good. In the modern era of high-efficiency teaching, teaching aids are even more important.

Contents of the invention

The purpose of the present invention is to address the deficiencies in the prior art, to provide a direct-acting follower cam-wheel train combination teaching aid, which can demonstrate the knowledge points of the motion laws of different direct-acting followers of the cam mechanism, and can realize direct-acting follower The shape of the head of the moving part can be changed, the eccentricity can be adjusted, the base circle and the theoretical contour can be expanded, the cam rotation angle can be read, the displacement of the linear follower can be read, the law of motion can be displayed, and the cam mechanism of the linear follower can be reversed Demonstration of method knowledge points, cam mechanism reverse method realization mechanism (planetary gear train mechanism) can be reused to demonstrate the conversion frame principle teaching of epicyclic gear train transmission ratio calculation.

In order to achieve the above object, the present invention adopts the following technical solutions.

The invention includes a total support, a drive conversion device, a transmission gear train mechanism, a planetary gear train mechanism and a cam assembly.

The drive conversion device includes a motor output shaft gear, a DC motor, a drive conversion support, a drive conversion adjustment device, a handle, a handle rotating disc, a handle fixed disc, a handle output shaft gear and a handle rotating shaft. The installation shaft of the drive conversion adjustment device is fixed on the adjustment support, and the adjustment support is fixed on the general bracket. switch between motor drive stations; the base of the DC motor is fixed at one end of the drive conversion support, and the output shaft of the DC motor is fixed with the motor output shaft gear; the handle rotation shaft is supported on the other end of the drive conversion support through rolling bearings One end; the handle output shaft gear is fixed on the handle rotating shaft; the handle rotating disc is interference fit with the handle rotating shaft; the handle fixing disc is fixed to the drive conversion support; the inner end surface of the handle fixing disc is along the circumference A plurality of steel ball grooves are evenly distributed; the inner end surface of the handle rotating disk is provided with a steel ball placement groove, one end of the steel ball spring is fixed with the steel ball placement groove, and the other end is fixed with the steel ball; the handle fixed disk and the handle rotating disk are in contact with each other through steel balls , the steel ball can be embedded in the steel ball groove; the outer rim of the handle rotating disc is fixed with a handle.

The transmission gear train mechanism includes a first input gear, an input shaft, a second input gear, a third input gear, a speed change control shaft, a first speed change gear, a second speed change gear, a first output gear, an output main shaft, a second output gear, the third output gear, the reverse disc panel, the reverse disc external gear, the first transmission gear, the second transmission gear, the transmission shaft, the reverse control gear and the reverse control shaft; the third input gear and The gear of the output shaft of the motor or the gear of the output shaft of the handle is meshed; the two ends of the input shaft, the output main shaft and the transmission shaft are all supported on the main support through rolling bearings; the speed change control shaft and the reverse control shaft are connected with the main support through linear bearings; The first input gear, the second input gear and the third input gear are all fixed on the input shaft; the first speed change gear and the second speed change gear are all fixed on the speed change control shaft; the first output gear, the second output gear and the third output gear are all fixed on the output main shaft; the external gear of the counter rotating disc is supported on the output main shaft through a rolling bearing; The reverse control gear is fixed on the reverse control shaft; both the first transmission gear and the second transmission gear are fixed on the transmission shaft; the first transmission gear meshes with the external gear of the reverse disc; the cam direct follower drives or revolves During the gear train transmission demonstration, the first speed change gear meshes with the second input gear and the first output gear at the same time; when the cam inversion method or the epicyclic gear train is transformed into a fixed-axis gear train to calculate the transmission ratio demonstration, the second speed change gear simultaneously meshes with the first output gear. An input gear meshes with the second output gear, and the reverse control gear meshes with the third output gear and the second transmission gear at the same time.

The planetary gear train mechanism includes a rotary disc internal gear, a planetary gear, a planet carrier rod, a fourth output gear and a planetary shaft; fixed; the fourth output gear is connected to the head of the output main shaft through a flat key; one end of the planet carrier rod is supported on the output main shaft through a rolling bearing; the planetary shaft is connected to the other end of the planet carrier rod through a flat key; The planetary gears are supported on the planetary shafts through rolling bearings, and mesh with the fourth output gear and the counter internal gear at the same time.

The cam assembly includes a panel bracket, a first panel, a second panel, a display box of a motion law diagram, a motion law pointer, a guide rod spring, a guide rod support, an adjustment screw, a stationary guide rod, a motion guide rod, and a slider , Slider adjustment support, cam, cam base circular plate, first peak joint, second peak joint, cam contour expansion plate, base circle expansion plate, wedge key, cam rotation angle moving pointer, cam rotation angle static pointer, dial , scale film, profiled pins, camshafts, pads, slide rails and slide rods. The panel bracket is sleeved outside the internal gear of the rotary disc and fixed with the overall bracket; the two slide rails are fixed radially on the outer end face rim of the internal gear of the rotary disc, and the two slide rails are connected to the inner counter Pads are provided between the inner gears of the turntable; the camshaft is coaxially arranged with the output spindle, and is connected with the planetary carrier rod through a flat key; both the first panel and the second panel are sleeved on the camshaft; The inner end surfaces of the first panel and the second panel are fixed with sliding rods, and the two sliding rods are respectively connected with the corresponding slide rails through sliding pairs; the joint surfaces of the first panel and the second panel are rectangular teeth that fit together , magnetites are fixed at the tooth tops of the first panel and the tooth grooves of the second panel; the cam and the cam base circular plate are connected with the camshaft by a flat key, and the cam base circular plate and the camshaft are connected by a wedge key connection; the cam is arranged on the outside of the first panel and the second panel; the inner end surface of the cam base circular plate is fixed to the outer end surface of the cam, and the dial is glued to the outer end surface of the cam base circular plate; the cam and the cam base circle There are annular slots on the contour surface of the board, the cam contour expansion board is inserted into the cam annular slot, the base circle expansion board is inserted into the cam base circular slot in the annular slot; the two sliders adjust the support fixed side by side on the second panel along the vertical direction; the two sliders are respectively connected with a slider adjustment support through a sliding pair, and are respectively fixed with a guide rod support; the slider adjustment support has multiple two threaded holes, and two guide rod supports are respectively connected with the corresponding slider adjustment support by screws at one threaded hole; the stationary guide rods and the moving guide rods are all aligned with the rotation center of the cam in the vertical direction, And both are connected with the two guide rod supports through a sliding pair; two guide rod springs are arranged between the two guide rod supports; the two guide rod springs are respectively sleeved on the stationary guide rod and the moving guide rod, and the top Tighten one spring pressing rod respectively; two spring pressing rods are respectively fixed on the static guide rod and the moving guide rod; the bottom of the static guide rod is glued with a scale film; There are joint installation holes, and the bottoms are all tapered; the joint installation holes on the top of the first peak joint are connected with the bottom of the motion guide rod through a transition fit, and the bottom and the cam are connected by a cam pair; the joint installation holes on the top of the second peak joint are connected to the static The bottom of the guide rod is transition-fit connected, and the bottom is connected with the cam base circular plate through the cam pair; the tail of the static pointer of the cam angle is transition-fit connected with the static indicator pin installation groove on the side wall of the second pointed joint; the tail of the dynamic pointer of the cam angle There is a connecting rod perpendicular to the plane where the needle head is located, and the connecting rod is embedded in the central hole of the head of the camshaft; the special-shaped pin shaft includes an integrally formed cylindrical part and a cuboid part, and the cuboid part is arranged on one end side wall of the cylindrical part The cylindrical part is fixed to the panel bracket, and the cuboid part is set horizontally; the motion law line diagram display box is provided with a special-shaped groove matching the shape of the special-shaped pin shaft, and the special-shaped groove of the motion law line diagram display box is socketed on the special-shaped pin shaft above; the bottom of the law of motion pointer is connected with the bottom of the law of motion line diagram display box through a sliding pair; the law of motion line diagram board is inserted into the drawing board slot of the law of motion line diagram display box, and the horizontal line on the law of motion line diagram display box Axes with The top horizontal tangent of the cam base circular plate is parallel; the axis of abscissa on the diagram of the law of motion is the rotation angle of the cam, and the axis of ordinate is the displacement of the motion guide rod.

The cam outline expansion plate is a transparent annular thin plate with slits, and the shape of the inner and outer contour surfaces is the same as that of the cam; the base circle expansion plate is a transparent annular thin plate with slits.

In the initial installation position, the sharp point of the head of the first pointed joint is in contact with the starting point of the lift of the cam, and the moving pointer of the cam rotation angle and the static pointer of the cam rotation angle point to the same scale of the dial.

The material of the motion rule diagram board is transparent plastic.

The first peak joint can be replaced by the first roller joint, and the second peak joint can be replaced by the second roller joint; the bottoms of the first roller joint and the second roller joint are hinged with rollers; the first roller The joint installation hole on the top of the sub-joint is connected with the bottom of the moving guide rod through a transition fit, and the bottom roller and the cam are connected through a cam pair; the joint installation hole on the top of the second roller joint is connected with the bottom of the stationary guide rod through a transition fit, The roller at the bottom is connected with the cam base circular plate through a cam pair; the tail of the static pointer of the cam rotation angle is transition-fit connected with the static pointer installation groove on the side wall of the second roller joint.

It is also possible to replace the first pointed top joint with a first flat bottom joint, and replace the second pointed top joint with a second flat bottom joint; the joint installation hole at the top of the first flat bottom joint is connected with the bottom of the motion guide rod through a transition fit, and the bottom and the cam pass through Cam pair connection; the joint installation hole on the top of the second flat bottom joint is connected with the bottom of the static guide rod through a transition fit, and the bottom is connected with the cam base circular plate through the cam pair; the tail of the static pointer of the cam rotation angle is connected with the static indication of the side wall of the second flat bottom joint Pin mounting slot transition fit connection.

The beneficial effect that the present invention has:

The invention can demonstrate the knowledge points of the motion laws of different linear followers of the cam mechanism, and can realize the changeable shape of the head of the linear follower, adjustable eccentricity, expandable base circle and theoretical profile, readable cam rotation angle, The movement displacement of the direct follower is readable, the law of motion is displayed, and the knowledge points of the cam mechanism reversal method of the direct follower are demonstrated. The mechanism (planetary gear train mechanism) realized by the cam mechanism reversal method can be reused to demonstrate the epicyclic gear train transmission Compared with the teaching of the conversion rack principle of calculation, it greatly deepens the understanding of students, facilitates teaching, and improves the quality of teaching.

Description of drawings

Fig. 1 is the perspective view of the overall structure of the present invention;

Fig. 2 is a sectional view of the overall structure of the present invention;

Fig. 3 is a side perspective view of the present invention;

Fig. 4 is another side perspective view of the present invention;

Fig. 5 is the perspective view of the structure of the planetary gear train mechanism in the present invention;

Fig. 6 is a schematic diagram of the transmission principle of the pointed straight follower cam mechanism in the present invention;

Fig. 7 is a schematic diagram of the transmission principle of the roller linear follower cam mechanism in the present invention;

Figure 8-1 is a perspective view of the structure of the first pointed joint in the present invention;

Figure 8-2 is a perspective view of the structure of the second pointed joint in the present invention;

Figure 9-1 is a perspective view of the structure of the first roller joint in the present invention;

Figure 9-2 is a perspective view of the structure of the second roller joint in the present invention;

Figure 10-1 is a perspective view of the structure of the first flat-bottom joint in the present invention;

Fig. 10-2 is a structural perspective view of the second flat-bottom joint in the present invention.

Detailed ways

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

As shown in Figures 1, 2, 3, 4 and 5, the direct-acting follower cam-gear combination teaching aid includes the overall bracket 2, the drive conversion device, the transmission gear train mechanism, the planetary gear train mechanism and the cam assembly; the transmission wheel There are two ways of driving the gear train, manual or electric. The conversion of the driving force is transmitted to the transmission gear train mechanism through the drive conversion device; the movement and reversal of the cam assembly are realized through the planetary gear train mechanism.

As shown in Figures 2, 3 and 4, the drive conversion device includes a motor output shaft gear 27, a DC motor 28, a drive conversion support 29, a drive conversion adjustment device 30, a handle 31, a handle rotating disc 32, a handle fixed disc 33, a handle Output shaft gear 34 and handle rotating shaft. The installation shaft of the drive conversion adjustment device 30 is fixed on the adjustment support 53, and the adjustment support 53 is fixed on the total support 2. The drive conversion support 29 is fixed with the adjustment arm of the drive conversion adjustment device 30, and the drive conversion adjustment device 30 can Switch between the manual station and the motor drive station to realize manual drive and motor drive respectively. The base of the DC motor 28 is fixed on one end of the drive conversion support 29, and the output shaft of the DC motor 28 is fixed with the motor output shaft gear 27. The handle rotation shaft is supported on the other end of the drive conversion support 29 through rolling bearings; the handle output shaft gear 34 is fixed on the handle rotation shaft; the handle rotation disc 32 is interference fit with the handle rotation shaft; Fixed; the inner end surface of the handle fixed plate 33 is provided with twelve steel ball grooves evenly distributed along the circumference. The inner end surface of the handle rotating disk 32 is provided with a steel ball placement groove, and one end of the steel ball spring is fixed with the steel ball placement groove, and the other end is fixed with the steel ball; The steel ball can be embedded in the steel ball groove; the handle 31 is fixed on the outer rim of the handle rotating disc 32 .

The transmission train mechanism includes a first input gear 35, an input shaft 36, a second input gear 37, a third input gear 38, a speed change control shaft 39, a first speed change gear 40, a second speed change gear 41, a first output gear 42, Output main shaft 43, second output gear 44, third output gear 45, reversing disc panel 46, reversing disc external gear 47, first transmission gear 48, second transmission gear 49, transmission shaft 50, reversing control gear 51 and the reverse control shaft 52; the third input gear 38 meshes with the motor output shaft gear 27 or the handle output shaft gear 34; the two ends of the input shaft 36, the output main shaft 43 and the transmission shaft 50 are all supported on the total support 2 by rolling bearings; The speed change control shaft 39 and the reverse control shaft 52 are all connected with the main support 2 through linear bearings; the first input gear 35, the second input gear 37 and the third input gear 38 are all fixed on the input shaft 36; the first speed change gear 40 and the second transmission gear 41 are all fixed on the transmission control shaft 39; the first output gear 42, the second output gear 44 and the third output gear 45 are all fixed on the output main shaft 43; On the output main shaft 43; the reversing disc panel 46 is vacantly sleeved on the output main shaft 43, and is fixed with the reversing disc external gear 47; the reversing control gear 51 is fixed on the reversing control shaft 52; the first transmission gear 48 and the second The transmission gears 49 are all fixed on the transmission shaft 50 ; the first transmission gear 48 meshes with the external gear 47 of the rotating disk. When demonstrating the transmission of the direct cam follower, the first transmission gear 40 meshes with the second input gear 37 and the first output gear 42 simultaneously, and the first output gear 42 drives the output main shaft 43 to run; the reverse control gear 51 does not participate in the meshing. During the demonstration of the cam inversion method, translate the speed change control shaft 39 and the reverse control shaft 52, so that the first speed change gear 40 is separated from the second input gear 37 and the first output gear 42, and the second speed change gear 41 is separated from the first input gear at the same time. 35 meshes with the second output gear 44, drives the output main shaft 43 to rotate, and the reverse control gear 51 meshes with the third output gear 45 and the second transmission gear 49 at the same time, and the power passes through the reverse control gear 51, the second transmission gear 49, the second transmission gear A transmission gear 48 is transmitted to the external gear 47 of the counter-rotating disc, thereby driving the panel 46 of the counter-rotating disc to rotate.

As shown in Figures 2, 3, 4 and 5, the planetary gear train mechanism includes a counter internal gear 54, a planetary gear 55, a planet carrier rod 56, a fourth output gear 57 and a planetary shaft 58; the counter internal gear 54 is empty Sleeve on the output main shaft 43 and fix it with the rotating disk panel 46; the fourth output gear 57 is connected with the head of the output main shaft 43 through a flat key; one end of the planet carrier rod 56 is supported on the output main shaft 43 through a rolling bearing; the planetary shaft 58 is connected with the other end of the planetary carrier rod 56 through a flat key; the planetary gear 55 is supported on the planetary shaft 58 through a rolling bearing, and meshes with the fourth output gear 57 and the counter internal gear 54 at the same time.

As shown in Figures 1, 2, 6, 8-1 and 8-2, the cam assembly includes a panel bracket 5, a first panel 6, a second panel 7, a display box 8 for a law of motion line diagram, a pointer 8-1 for a law of motion, Guide rod spring 9, guide rod support 10, adjusting screw 11, stationary guide rod 12, moving guide rod 13, slider 14, slider adjustment support 15, cam 16, cam base circular plate 17, first pointed joint 18 , the second peak joint 18-1, the cam outline expansion plate 20, the base circle expansion plate 21, the wedge key 22, the cam rotation angle moving pointer 23, the cam rotation angle static pointer 24, the dial plate 25, the scale film 26, the special-shaped pin shaft 59 , Camshaft 60, pad 61, slide rail 62 and slide rod 63. The panel bracket 5 is sleeved outside the internal gear 54 of the rotary disc, and is fixed with the main bracket 2; two slide rails 62 are fixed radially on the outer end face rim of the internal gear 54 of the rotary disc, and the two slide rails 62 Pads 61 are provided between the internal gear 54 of the inner revolving disc; the camshaft 60 is arranged coaxially with the output main shaft 43, and is connected with the planet carrier rod 56 through a flat key; the first panel 6 and the second panel 7 are both set Placed on the camshaft 60; the inner end surfaces of the first panel 6 and the second panel 7 are fixed with sliding rods 63, and the two sliding rods 63 are respectively connected with the corresponding slide rails 62 through sliding pairs; the first panel 6 and the second The joint surface of the panel 7 is a rectangular tooth that fits each other, and magnetites are fixed at the top of the tooth of the first panel 6 and the tooth groove of the second panel 7; Key connection, and the cam base disc 17 is connected with the camshaft 60 through the wedge key 22, and the wedge key 22 realizes the axial positioning of the cam base disc 17; the cam 16 is arranged on the outside of the first panel 6 and the second panel 7; the cam The inner end face of the base circular plate 17 is fixed with the outer end face of the cam 16, and the dial 25 is glued to the outer end face of the cam base circular plate 17; The line expansion plate 20 is plugged in the annular slot of the cam 16; the cam outline expansion plate 20 is a transparent annular thin plate with a slit, and the shape of the inner and outer contour surfaces is the same as that of the cam 16; the base circle expansion plate 21 is a transparent annular thin plate with a gap, inserted in the annular slot of the cam base disc 17; two slider adjustment supports 15 are fixed side by side on the second panel 7 along the vertical direction; two sliders 14 They are respectively connected with a slider adjustment support 15 through a sliding pair, and a guide rod support 10 is respectively fixed; the slider adjustment support 15 is provided with six threaded holes, and the two guide rod supports 10 are respectively connected with the corresponding slide The block adjustment support 15 is connected by a screw 11 at a threaded hole; the stationary guide rod 12 and the moving guide rod 13 are all aligned with the rotation center of the cam 16 in the vertical direction, and are connected with the two guide rod supports 10 through a sliding pair. Connection; the guide rod support 10 is fixed at different threaded holes of the slider adjustment support 15 by screws 11, and the eccentric distance between the stationary guide rod 12 and the moving guide rod 13 and the rotation center of the cam 16 can be adjusted simultaneously; two Two guide rod springs 9 are arranged between the guide rod supports 10; the two guide rod springs 9 are respectively sleeved on the stationary guide rod 12 and the moving guide rod 13, and a spring pressing rod is respectively pressed on the top; The spring pressure rods are respectively fixed on the stationary guide rod 12 and the moving guide rod 13; the bottom of the static guide rod 12 is glued with a scale film 26; the tops of the first peak joint 18 and the second peak joint 18-1 are provided with joint installation holes , the bottoms are conical; the joint installation hole at the top of the first pointed joint 18 is connected with the bottom of the motion guide rod 13 through a transition fit, and the bottom is connected with the cam 16 through a cam pair; the joint installation hole at the top of the second pointed joint 18-1 is connected with The bottom of the static guide rod 12 is connected by a transition fit, and the bottom is connected with the cam base circular plate 17 through a cam pair; the tail of the static pointer 24 of the cam rotation angle The end is connected with the static indicator needle installation groove on the side wall of the second peak joint 18-1 through transition fit; the tail of the cam angle moving pointer 23 is provided with a connecting rod perpendicular to the plane where the needle head is located, and the connecting rod is embedded in the center hole of the head of the camshaft 60 Inside; in the initial installation position, the point of the head of the first pointed joint 18 is in contact with the starting point of the lift of the cam 16, and the cam rotation angle moving pointer 23 and the cam rotation angle static pointer 24 point to the same scale of the dial 25, which can be read from the dial 25 Read the angle of rotation of the cam rotation angle moving pointer 23 relative to the cam rotation angle static pointer 24, thereby determining the rotation angle of the cam base circular plate 17. The special-shaped pin shaft 59 comprises an integrally formed cylindrical part and a cuboid part, and the cuboid part is arranged on an end side wall of the cylindrical part; the cylindrical part is fixed with the panel support 5, and the cuboid part is horizontally arranged; The shape of the pin shaft 59 matches the special-shaped groove, and the special-shaped groove of the motion law line diagram display box 8 is socketed on the special-shaped pin shaft 59; after the motion law line diagram display box 8 is used, it can be taken off from the special-shaped pin shaft 59 for storage Place; the bottom of the law of motion pointer 8-1 is connected with the bottom of the law of motion line diagram display box 8 by a sliding pair; The abscissa axis on the top is parallel to the top horizontal tangent line of the cam base circular plate 17; the material of the law of motion diagram board is transparent plastics, and according to different straight-acting follower cam mechanisms, the corresponding law of motion diagram board can be replaced; The axis of abscissa on the regular line drawing board is the angle of rotation of cam 16, and the ordinate is the displacement of motion guide rod 13; Pointer 8-1 indicates the corresponding relationship between the cam motion law and the cam rotation angle and the displacement of the motion guide rod, realizing the explanation of the cam profile, the cam rotation angle, the displacement of the cam direct follower, and the knowledge points of the cam motion law, with multiple motion law diagram boards Stacking can compare the similarities and differences of the motion laws of different linear followers under the same cam profile.

As shown in Figures 1, 7, 9-1 and 9-2, the first peak joint 18 can be replaced with a first roller joint 19, and the second peak joint 18-1 can be replaced with a second roller joint 19-1; The bottoms of the first roller joint 19 and the second roller joint 19-1 are all hinged with rollers; the joint installation hole at the top of the first roller joint 19 is connected with the bottom of the motion guide rod 13 through a transition fit, and the roller at the bottom is connected with The cam 16 is connected by a cam pair; the joint installation hole at the top of the second roller joint 19-1 is connected with the bottom of the stationary guide rod 12 through a transition fit, and the roller at the bottom is connected with the cam base circular plate 17 by a cam pair; the static pointer of the cam rotation angle The tail portion of 24 is transition-fit connected with the static indicator needle mounting groove on the side wall of the second roller joint 19-1.

As shown in Figures 1, 10-1 and 10-2, the first pointed joint 18 can also be replaced with a first flat joint 64, and the second pointed joint 18-1 can be replaced with a second flat joint 64-1; the first flat joint The joint mounting hole at the top of the joint 64 is connected with the bottom of the moving guide rod 13 through transition fit, and the bottom is connected with the cam 16 through a cam pair; the joint mounting hole at the top of the second flat bottom joint 64-1 is connected with the bottom of the stationary guide rod 12 through a transition fit, The bottom is connected with the cam base circular plate 17 through a cam pair; the tail of the cam angle static pointer 24 is transition-fit connected with the static pointer installation groove on the side wall of the second flat-bottom joint 64-1.

The working principle of the direct follower cam-gear combination teaching aid:

The drive conversion device can realize manual and electric drive modes: when the drive conversion adjustment device 30 switches to the motor drive station, the motor output shaft gear 27 meshes with the third input gear 38, and the DC motor 28 drives the third input gear 38 through the motor output shaft gear 27. The three input gears 38 rotate; when the drive conversion adjustment device 30 is switched to the manual station, the handle output shaft gear 34 meshes with the third input gear 38, and the handle 31 drives the handle output shaft gear 34 to rotate through the handle rotating disc 32 and the handle rotating shaft; The handle fixed disk 33 contacts the handle rotating disk 32 through steel balls. During the rotation of the handle rotating disk 32, the steel balls rely on the pressure of the steel ball spring to embed in the steel ball groove of the handle fixed disk 33 to realize indexing rotation.

Deduce the knowledge points of the known cam profile to find the law of motion:

The drive conversion device drives the third input gear 38 to rotate, and the power of the third input gear 38 is passed to the second input gear 37 through the input shaft 36; The first output gear 42, the first output gear 42 drives the output main shaft 43 to rotate; the fourth output gear 57 rotates at the same speed with the output main shaft 43, and the planetary gear 55 meshes with the fourth output gear 57, driving the planet carrier rod 56 to rotate, and then driving The cam 16 and the cam-based circular plate 17 rotate; at this time, the reverse control gear 51 does not participate in meshing, the internal gear 54 of the reverse disc is stationary, and the first panel 6 and the second panel 7 do not move. Cam 16 rotates and promotes first apex joint 18 to make motion guide rod 13 move vertically, and motion guide rod 13 compresses cam 16 all the time under the effect of guide rod spring 9; Moving; the cam angle moving pointer 23 rotates with the cam base disc 17, and the angle of the cam angle moving pointer 23 relative to the cam angle static pointer 24 can be read from the dial 25, thereby determining the angle of rotation of the cam base disc 17; from the scale film 26, read the scale value that the moving guide rod 13 moves relative to the stationary guide rod 12, that is, the displacement of the cam linear follower; the guide rod support 10 and the slider adjustment support 15 are connected by screws 11 at different threaded holes , the eccentricity of the cam mechanism of the straight-acting follower can be adjusted; the point position of the head point of the first pointed joint 18 corresponds to the contour line of the cam 16. At this time, the theoretical contour line coincides with the actual contour line of the cam, and the base circle of the cam The outline of plate 17 is the base circle of the cam, which demonstrates that the theoretical outline of the pointed direct follower cam mechanism coincides with the actual outline of the cam, the eccentricity of the pointed direct follower cam mechanism is adjustable, and the knowledge points of the cam base circle.

Replace the first peak joint 18 with the first roller joint 19, and replace the second peak joint 18-1 with the second roller joint 19-1. At this time, the center position of the roller of the first roller joint 19 and the convex profile Corresponding to the outline of the line expansion plate 20, the outline of the cam outline expansion plate 20 is the theoretical outline of the roller linear follower cam mechanism, and the outline of the cam 16 is the actual roller linear follower cam mechanism. Profile, base circle The profile of the expansion plate 21 is the base circle of the cam, which can demonstrate the difference between the theoretical profile and the actual profile of the roller linear follower cam mechanism, and can also compare the peak linear follower cam mechanism with the The similarities and differences between the theoretical profile and the actual profile of the roller linear follower cam mechanism under the same cam profile. In the same way, in the roller direct-acting follower cam mechanism, the angle of rotation of the cam rotation angle moving pointer 23 relative to the cam rotation angle static pointer 24 can be read from the dial 25, thereby determining the rotation angle of the cam base circular plate 17; from the scale film 26 Read the scale value that the moving guide rod 13 moves relative to the stationary guide rod 12, that is, the angular displacement of the cam linear follower.

Replace the first pointed joint 18 with the first flat joint 64, and replace the second pointed joint 18-1 with the second flat joint 64-1; the position of the bottom of the first flat joint 64 corresponds to the outline of the cam 16. At this time, The theoretical profile coincides with the actual profile of the cam, and the profile of the cam base circular plate 17 is the cam base circle, which can demonstrate the cam mechanism of the flat-bottomed linear follower.

Deduce the principle of the inversion method of the pointed direct follower cam mechanism:

Toggle the cam rotation angle moving pointer 23 to point to the starting point of the lift of the cam 16, the cam rotation angle static pointer 24 coincides with the cam rotation angle moving pointer 23; the drive conversion device drives the third input gear 38 to rotate, and the power of the third input gear 38 passes through the input shaft 36 Pass to the first input gear 35; translate the speed change control shaft 39 and the reverse control shaft 52, so that the second speed change gear 41 meshes with the first input gear 35 and the second output gear 44 at the same time, driving the output main shaft 43 and the fourth output gear 57 to The speed rotates, and the fourth output gear 57 drives the planetary gear 55 to rotate, thereby driving the planet carrier rod 56 to The speed rotation; reverse control gear 51 meshes with the third output gear 45 and the second transmission gear 49 at the same time, the power of the output main shaft 43 passes through the third output gear 45, the reverse control gear 51, the second transmission gear 49, the first The transmission gear 48 is transmitted to the external gear 47 of the rotary disc, thereby driving the panel 46 of the rotary disc and the internal gear 54 of the rotary disc to reverse, the internal gear 54 of the rotary disc meshes with the planetary gear 55, and drives the planet carrier rod 56 to The speed is reversed, the two movements are synthesized, the planetary carrier rod 56 is stationary, so that the cam 16 and the cam base plate 17 are stationary; the internal gear 54 of the reversing disk drives the first panel 6, the second panel 7 and the dial 25 to reverse synchronously ; The stationary guide rod 12 reverses with the first panel 6, and slides along the contour surface of the cam-based circular plate 17; the moving guide rod 13 reverses with the first panel 6 on the one hand, and is pushed by the cam 16 on the other hand, along the guide rod The support 10 slides, and the position of the first pointed joint 18 is the contour point of the cam 16; the scale value of the movement of the moving guide rod 13 relative to the stationary guide rod 12 can be read from the scale film 26, that is, the direct motion follower of the cam The displacement of the cam rotation angle static pointer 24 rotates with the stationary guide rod 12, and the angle at which the stationary guide rod 12 rotates relative to the moving guide rod 13 can be read from the dial 25, thereby determining the rotation angle of the cam-based circular plate 17; the knowledge points are introduced in detail At this time, the inversion of the cam mechanism of the direct-acting follower is realized by manual driving, and the displacement of the direct-acting follower at different cam angles is determined in the process of the first panel 6 inversion according to the motion law chart, and the deduction Under the condition of known motion law, the drawing principle of the cam contour.

The principle of the reverse method of the roller direct follower cam mechanism and the flat linear follower cam mechanism is similar to the principle of the reverse method of the pointed direct follower cam mechanism.

Deduce the transmission principle of the epicyclic gear train: remove the cam rotation angle moving pointer 23, the cam rotation angle static pointer 24, the cam base circular plate 17, the cam 16, the first panel 6, the second panel 7 and the camshaft 60; mode to drive the third input gear 38 to rotate, and the power of the third input gear 38 is passed to the second input gear 37 through the input shaft 36; the translation shift control shaft 39 makes the first shift gear 40 simultaneously with the second input gear 37 and the first The output gear 42 meshes, and the first output gear 42 drives the output main shaft 43 to rotate; the fourth output gear 57 rotates at the same speed with the output main shaft 43, and the planetary gear 55 meshes with the fourth output gear 57, driving the planet carrier rod 56 to rotate; at this time, The reverse control gear 51 does not participate in meshing, the reverse disc internal gear 54 is static, and the wheel train is an epicyclic gear train.

Deduce the principle of the conversion mechanism method of converting the epicyclic gear train into a fixed-axis gear train to calculate the transmission ratio: the cam rotation angle moving pointer 23, the cam rotation angle static pointer 24, the cam base circular plate 17, the cam 16, the first panel 6, and the second panel 7 and the camshaft 60 are disassembled; the drive conversion device drives the third input gear 38 to rotate in an electric manner, and the power of the third input gear 38 is transmitted to the first input gear 35 through the input shaft 36; the translational speed change control shaft 39 and the reverse control shaft 52, so that the second transmission gear 41 meshes with the first input gear 35 and the second output gear 44 at the same time, driving the output main shaft 43 and the fourth output gear 57 to The speed rotates, and the fourth output gear 57 drives the planetary gear 55 to rotate, thereby driving the planet carrier rod 56 to The speed of forward rotation; the reverse control gear 51 meshes with the third output gear 45 and the second transmission gear 49 at the same time, and the power of the output main shaft 43 passes through the third output gear 45, the reverse control gear 51, the second transmission gear 49, the second transmission gear 49, A transmission gear 48 is transmitted to the external gear 47 of the rotary disc, thereby driving the panel 46 of the rotary disc and the internal gear 54 of the rotary disc to reverse, the internal gear 54 of the rotary disc meshes with the planetary gear 55, and drives the planet carrier rod 56 to The speed is reversed, the two motions are synthesized, and the planetary carrier rod 56 is stationary; at this time, the rotation centers of the fourth output gear 57, the planetary gear 55 and the rotary disc internal gear 54 are all fixed, and the epicyclic gear train is transformed into a fixed axis Gear train, introduces the knowledge points of calculating the transmission ratio of epicyclic gear train according to the fixed axis gear train formula.

In this direct-acting follower cam-gear combination teaching aid, the movement and reversal of the cam assembly are realized through the planetary gear mechanism, and the principle of reversal is intuitive; it covers the pointed direct-acting follower cam mechanism, roller direct-acting Explanation of the knowledge points of the motion law of the follower cam mechanism and flat-bottom linear follower cam mechanism, which realizes the expansion of the base circle and the theoretical profile, readable cam rotation angle, readable displacement of the linear follower, and corresponding display of motion laws It is reused with the planetary gear train mechanism to demonstrate the innovative function of the conversion rack principle for the calculation of the transmission ratio of the epicyclic gear train; when the details of the knowledge points of the cam motion law are displayed, the drive of the transmission gear train mechanism is manually driven; the reverse method of the cam mechanism is deduced Principle, transmission principle of epicyclic gear train and conversion mechanism method principle for calculating transmission ratio of epicyclic gear train into fixed axle gear train, the drive of transmission gear train mechanism adopts electric mode, which is convenient for demonstration and operation.

By watching the demonstration of the direct follower cam-wheel train combination teaching aid, students can more easily understand knowledge points vividly, vividly and intuitively, stimulate learning interest, and at the same time reduce the difficulty of teaching for teachers and improve the quality of teaching; teachers More energy can be put on guiding students to observe teaching aids, and cultivating students' ability to analyze, think, ask questions and solve problems. The direct-acting follower cam-wheel train combined teaching aid has a compact structure and is easy to carry.

Claims (6)

1. Direct-acting follower cam-gear combination teaching aids, including a total bracket, a drive conversion device, a transmission gear train mechanism, a planetary gear train mechanism and a cam assembly, characterized in that: The drive conversion device includes a motor output shaft gear, a DC motor, a drive conversion support, a drive conversion adjustment device, a handle, a handle rotating disk, a handle fixed disk, a handle output shaft gear and a handle rotation shaft; the drive conversion adjustment device The installation shaft is fixed on the adjustment support, the adjustment support is fixed on the general bracket, the drive conversion support is fixed with the adjustment arm of the drive conversion adjustment device, and the drive conversion adjustment device can be switched between the manual station and the motor drive station The base of the DC motor is fixed on one end of the drive conversion support, and the output shaft of the DC motor is fixed to the motor output shaft gear; the handle rotation shaft is supported on the other end of the drive conversion support through rolling bearings; the handle The output shaft gear is fixed on the handle rotating shaft; the handle rotating disc is interference fit with the handle rotating shaft; the handle fixing disc is fixed to the drive conversion support; the inner end surface of the handle fixing disc is evenly distributed along the circumference with multiple Steel ball groove; the inner end surface of the handle rotating disk is provided with a steel ball placement groove, one end of the steel ball spring is fixed with the steel ball placement groove, and the other end is fixed with the steel ball; the handle fixed disk and the handle rotating disk are in contact with the steel ball, and the steel ball can be embedded in the steel ball groove In the groove; the outer rim of the handle rotating disc is fixed with a handle; The transmission gear train mechanism includes a first input gear, an input shaft, a second input gear, a third input gear, a speed change control shaft, a first speed change gear, a second speed change gear, a first output gear, an output main shaft, a second output gear, the third output gear, the reverse disc panel, the reverse disc external gear, the first transmission gear, the second transmission gear, the transmission shaft, the reverse control gear and the reverse control shaft; the third input gear and The gear of the output shaft of the motor or the gear of the output shaft of the handle is meshed; the two ends of the input shaft, the output main shaft and the transmission shaft are all supported on the main support through rolling bearings; the speed change control shaft and the reverse control shaft are connected with the main support through linear bearings; The first input gear, the second input gear and the third input gear are all fixed on the input shaft; the first speed change gear and the second speed change gear are all fixed on the speed change control shaft; the first output gear, the second output gear and the third output gear are all fixed on the output main shaft; the external gear of the counter rotating disc is supported on the output main shaft through a rolling bearing; The reverse control gear is fixed on the reverse control shaft; both the first transmission gear and the second transmission gear are fixed on the transmission shaft; the first transmission gear meshes with the external gear of the reverse disc; the cam direct follower drives or revolves During the gear train transmission demonstration, the first speed change gear meshes with the second input gear and the first output gear at the same time; when the cam inversion method or the epicyclic gear train is transformed into a fixed-axis gear train to calculate the transmission ratio demonstration, the second speed change gear simultaneously meshes with the first output gear. The first input gear meshes with the second output gear, and the reverse control gear meshes with the third output gear and the second transmission gear at the same time; The planetary gear train mechanism includes a rotary disc internal gear, a planetary gear, a planet carrier rod, a fourth output gear and a planetary shaft; fixed; the fourth output gear is connected to the head of the output main shaft through a flat key; one end of the planet carrier rod is supported on the output main shaft through a rolling bearing; the planetary shaft is connected to the other end of the planet carrier rod through a flat key; The planetary gear is supported on the planetary shaft through a rolling bearing, and meshes with the fourth output gear and the internal gear of the counter disk at the same time; The cam assembly includes a panel bracket, a first panel, a second panel, a display box of a motion law diagram, a motion law pointer, a guide rod spring, a guide rod support, an adjustment screw, a stationary guide rod, a motion guide rod, and a slider , Slider adjustment support, cam, cam base circular plate, first peak joint, second peak joint, cam contour expansion plate, base circle expansion plate, wedge key, cam rotation angle moving pointer, cam rotation angle static pointer, dial , scale film, special-shaped pin shaft, camshaft, cushion block, slide rail and slide rod; the panel bracket is sleeved outside the inner gear of the rotary disc and fixed with the total bracket; the two slide rails are fixed radially on the The outer end face of the inner gear of the rotary disc is on the rim, and there are pads between the two slide rails and the inner gear of the inner rotary disc; the camshaft is coaxially arranged with the output main shaft, and passes through the planet carrier rod Flat key connection; the first panel and the second panel are sleeved on the camshaft; the inner end surfaces of the first panel and the second panel are fixed with sliding rods, and the two sliding rods are respectively slid with the corresponding slide rails. Auxiliary connection; the joint surface of the first panel and the second panel is a rectangular tooth that fits each other, and magnetites are fixed at the top of the tooth of the first panel and the tooth groove of the second panel; the cam and the cam-based circular plate Both are connected with the camshaft by a flat key, and the cam base disc and the cam shaft are connected by a wedge key; the cam is arranged on the outside of the first panel and the second panel; the inner end surface of the cam base disc is fixed to the outer end surface of the cam, and the scale The disk is glued to the outer end surface of the cam base circular plate; the cam and the profile surface of the cam base circular plate are provided with annular slots, and the cam outline expansion plate is plugged into the annular slot of the cam, and the base circle expansion plate Inserted in the annular slot of the cam base circular plate; two slider adjustment supports are fixed side by side on the second panel along the vertical direction; the two sliders are respectively connected with one slider adjustment support through a sliding pair, and A guide rod support is respectively fixed; the slider adjustment support is provided with a plurality of threaded holes, and the two guide rod supports are respectively connected with the corresponding slider adjustment support by screws at a threaded hole; Both the stationary guide rod and the moving guide rod are aligned with the rotation center of the cam in the vertical direction, and are connected with the two guide rod supports through sliding pairs; two guide rod springs are arranged between the two guide rod supports; Two guide rod springs are sleeved on the stationary guide rod and the moving guide rod respectively, and one spring pressing rod is respectively pressed on the top; the two spring pressing rods are respectively fixed on the stationary guiding rod and the moving guiding rod; The bottom is glued with a scale film; the tops of the first pointed joint and the second pointed joint are provided with joint installation holes, and the bottoms are both tapered; the joint installation holes on the top of the first pointed joint are transitionally fitted with the bottom of the motion guide rod , the bottom is connected with the cam through a cam pair; the joint installation hole at the top of the second pointed joint is connected with the bottom of the stationary guide rod through a transition fit connection, and the bottom is connected with the cam base circular plate through a cam pair; the tail of the static pointer of the cam rotation angle is connected with the second The static indicator pin installation groove on the side wall of the pointed joint is transitionally fitted and connected; the tail of the cam angle dynamic pointer is provided with a connecting rod perpendicular to the plane where the needle head is located, and the connecting rod is embedded in the center hole of the head of the camshaft; the special-shaped pin includes One-piece cylindrical part and cuboid part, cuboid part It is separately arranged on the side wall of one end of the cylindrical part; the cylindrical part is fixed with the panel bracket, and the rectangular parallelepiped part is arranged horizontally; the motion law line diagram display box is provided with a special-shaped groove matching the shape of the special-shaped pin shaft, and the motion law line diagram is displayed The special-shaped groove of the box is socketed on the special-shaped pin shaft; the bottom of the law of motion pointer is connected with the bottom of the line diagram display box of the law of motion through a sliding pair; the line drawing board of the law of motion is inserted into the drawing board slot of the line diagram display box of the law of motion In , the axis of abscissa on the motion law diagram is parallel to the top horizontal tangent of the cam-based circular plate; the axis of abscissa on the motion law diagram is the rotation angle of the cam, and the ordinate is the displacement of the motion guide rod. 2. The direct-acting follower cam-wheel train combination teaching aid according to claim 1, characterized in that: the cam outline extension plate is a transparent annular thin plate with gaps, and the shape of the inner and outer contour surfaces is the same as that of The profile surfaces of the cams have the same shape; the base circle expansion plate is a transparent annular thin plate with a slit. 3. The direct-acting follower cam-gear combination teaching aid according to claim 1, characterized in that: at the initial installation position, the point of the head of the first pointed joint is in contact with the starting point of the lift of the cam, and the rotation angle of the cam The pointer and the static pointer of the cam angle point to the same scale of the dial. 4. The linear follower cam-gear train combination teaching aid according to claim 1, characterized in that: the material of the motion rule diagram board is transparent plastic. 5. The direct follower cam-wheel train combined teaching aid according to claim 1, characterized in that: the first pointed joint can be replaced with the first roller joint, and the second pointed joint can be replaced with the second roller joint ; The bottoms of the first roller joint and the second roller joint are hinged with rollers; the joint installation hole at the top of the first roller joint is connected with the bottom of the motion guide bar through a transition fit, and the bottom roller and the cam pass through the cam Auxiliary connection; the joint installation hole on the top of the second roller joint is connected with the bottom of the stationary guide rod through a transition fit connection, and the roller at the bottom is connected with the cam base circular plate through the cam pair; the tail of the static pointer of the cam rotation angle is connected with the second roller Static indicator pin mounting slot transition fit connection on side wall of connector. 6. The direct driven follower cam-wheel train combination teaching aid according to claim 1, characterized in that: the first pointed joint can be replaced with a first flat joint, and the second pointed joint can be replaced with a second flat joint; The joint installation hole on the top of the first flat-bottomed joint is transition-fit connected with the bottom of the moving guide rod, and the bottom is connected with the cam through the cam pair; the joint installation hole at the top of the second flat-bottomed joint is connected with the bottom of the stationary guide rod through transition fit, and the bottom is connected with the cam The base circular plate is connected by a cam pair; the tail of the cam rotation angle static pointer is transition-fit connected with the static pointer installation groove on the side wall of the second flat-bottomed joint.