CN104299508B - Cam profile curve is drawn demonstrator - Google Patents

Abstract

The invention discloses a demonstration instrument for drawing cam contour curves, which comprises a frame, an outer shaft, an inner shaft and a drawing board, the drawing board is arranged on the front side of the frame, a cross bracket is arranged between the drawing board and the frame, and a bottom is installed on the lower part of the frame shaft, the bottom shaft gear is installed on the bottom shaft, the outer shaft passes through the front side of the frame and the cross bracket and is connected with the frame, the outer shaft gear is installed on the outer shaft, the outer shaft gear meshes with the bottom shaft gear, the inner shaft and the outer shaft The shaft is rotationally connected, the rear end of the inner shaft is connected to the frame, the drawing board is installed at the front end of the inner shaft, a central gear is installed on the inner shaft between the drawing board and the cross bracket, and a follower is provided on the upper front side of the cross bracket, and the follower A painting brush is arranged on the front side of the lower part, a pin is fixed on the lower part of the follower, a rack plate is provided between the follower and the cross bracket, a curved groove is opened on the rack plate, the pin passes through the curved groove, and the rack plate and the The sun gear meshes. The invention can not only demonstrate the reverse method to draw the cam profile curve, but also can demonstrate the motion of the original mechanism before the reverse.

Description

Demonstration instrument for cam profile curve drawing

technical field

The invention relates to a teaching demonstration instrument, in particular to a cam profile curve drawing demonstration instrument.

Background technique

In the course of "Principles of Mechanics", the content of cam profile curve design by inversion method is relatively abstract. When teachers explain, they only use drawing on the blackboard and verbal description, which is not easy to explain clearly, and many students are not easy to understand deeply. In order to accurately and quickly understand the principle of designing the cam profile curve by the inversion method, it is necessary to have a vivid, specific and intuitive understanding of the movement of each component of the cam mechanism after the frame is changed. However, the schematic diagram of mechanism movement drawn on the blackboard is static, and teachers often spend a lot of time and energy explaining it from various angles, and students must use imagination to animate the static mechanism movement diagram. This kind of imagination is not very clear, and it is difficult for students to have a vivid, specific and intuitive understanding of the kinematic relationship of each component, and it is also impossible to clearly and accurately understand the principle of designing the cam profile curve by the inversion method.

In order to intuitively demonstrate the principle of the inversion method, the cam must be fixed, the original frame and the follower rotate around the cam, and the follower moves according to a given law of motion. Moreover, the teaching aid should have a component that can visually represent the motion diagram of the follower (s displacement-rotation angle δ curve). Although some teaching aids related to the cam mechanism can demonstrate the motion of the cam mechanism, they cannot demonstrate the reverse method to draw the cam profile curve, and students still cannot understand the reverse method to draw the cam profile curve well.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies in the above-mentioned prior art, and provide a cam profile curve drawing demonstration instrument, which can not only demonstrate the reverse method to draw the cam profile curve, but also demonstrate the movement of the original mechanism before the reverse, with a compact structure, Reasonable design, easy to use and operate.

In order to achieve the above object, the technical solution adopted by the present invention is: a cam profile curve drawing demonstration instrument, characterized in that it includes a frame, an outer shaft, an inner shaft and a drawing board, and the drawing board is arranged on the front side of the frame. The drawing board is a transparent board, a cross bracket is arranged between the drawing board and the frame, a bottom shaft is installed on the lower part of the frame for rotation, a bottom shaft gear is fixedly installed on the bottom shaft, and the outer shaft is a hollow shaft , the outer shaft passes through the front side of the frame and the cross bracket and is rotatably connected with the frame, the outer shaft is fixedly connected with the cross bracket, the outer shaft gear is fixedly installed on the outer shaft, the outer shaft gear and Bottom shaft gears are all arranged in the frame, the outer shaft gear is located above the bottom shaft gear and meshed with the bottom shaft gear, the two ends of the inner shaft pass through the two ends of the outer shaft respectively, the inner shaft and the outer shaft The shaft is rotatably connected, the rear end of the inner shaft passes through the frame and is rotatably connected with the frame, the drawing board is fixedly installed on the front end of the inner shaft, and a central gear is fixedly installed on the inner shaft between the drawing board and the cross bracket, The upper front side of the cross bracket is provided with a follower capable of vertically sliding along the cross bracket, the lower front side of the follower is provided with a paintbrush, and the lower part of the follower is fixed with a pin. A rack plate is arranged between the follower and the cross bracket, and the rack plate can slide horizontally along the cross bracket. A curved groove is opened on the rack plate, and the pin passes through the curved groove. The rack plate Located above and meshing with the sun gear.

The above-mentioned cam profile curve drawing demonstration instrument is characterized in that: the upper part of the frame is equipped with a locking tooth plate through a sliding shaft, the sliding shaft is fixed on the frame, and the number of the sliding shafts is two and two The sliding shafts are parallel, the sliding shaft is arranged above the inner shaft, the locking tooth plate is located in the frame, the sliding shaft passes through the locking tooth plate and the locking tooth plate can slide back and forth along the sliding shaft, the locking tooth The plate cooperates with the outer shaft gear.

The above-mentioned cam profile curve drawing demonstration instrument is characterized in that: it also includes a side shaft, the front end of the side shaft passes through the upper part of the frame and is rotatably connected with the frame, the side shaft is parallel to the inner shaft, and the side shaft A side shaft gear is fixedly installed on the shaft, and an inner shaft gear is fixedly installed on the inner shaft. Both the inner shaft gear and the side shaft gear are located in the frame, and the inner shaft gear meshes with the side shaft gear. The inner shaft gear is located below the lock tooth plate and cooperates with the lock tooth plate.

The above-mentioned cam profile curve drawing demonstration instrument is characterized in that: the rear end of the bottom shaft is fixedly connected with the first handle, and the rear end of the side shaft is fixedly connected with the second handle.

The above-mentioned cam profile curve drawing demonstration instrument is characterized in that: the follower is a slide rail, and the upper end of the front side of the cross bracket is fixed with a first slider, and the first slider cooperates with the follower, There are two first sliders, and the two first sliders are arranged symmetrically up and down.

The above-mentioned cam profile curve drawing demonstration instrument is characterized in that: the rear side of the rack plate is fixed with a second slide block, the front side of the cross bracket is fixed with a slide rail, and the slide rail is connected to the second slide block. Cooperate.

The above-mentioned cam profile curve drawing demonstration instrument is characterized in that: the lower edge of the rack plate is provided with gear teeth, and the number of gear teeth on the lower edge of the rack plate is greater than the number of gear teeth on the rim of the central gear.

The above-mentioned cam profile curve drawing demonstration instrument is characterized in that: the outer shaft passes through the center of the cross bracket.

The above-mentioned cam profile curve drawing demonstration instrument is characterized in that: the center lines of the outer shaft and the inner shaft coincide.

The above-mentioned cam profile curve drawing demonstration instrument is characterized in that: the shape of the drawing board is circular, and the outer periphery of the drawing board is provided with an angle scale.

Compared with the prior art, the present invention has the following advantages:

1. When the present invention assists teaching, the teacher can demonstrate while explaining, and demonstrate the principle of "inversion method" many times in a short period of time, and students can also observe the relative motion relationship of each component in the mechanism more intuitively, so that The abstract teaching content becomes vivid and intuitive, which is convenient for teachers to explain and helps students to understand, thereby greatly stimulating students' interest in learning, enhancing teaching effects, and improving teaching quality.

2. The present invention utilizes the rack and pinion mechanism to expand the cam angle into linear coordinates, and utilizes the direct motion cam mechanism to make the follower move according to a given S-δ curve, thereby visually embodying the movement law of the cam follower In the actual mechanism, the demonstrator has a compact structure and a simple shape.

3. The inner shaft and the outer shaft of the present invention adopt the design of the sleeve shaft, which is convenient for rack switching. The rack switching part uses the cooperation of the locking tooth plate and the outer shaft gear or the inner shaft gear to realize the circumferential direction of the outer shaft or the inner shaft. Fixed, the operation is very simple, and the rack switching can be completed in one step.

4. The present invention has multiple demonstration functions. During the demonstration process, the movement relationship of each component after the frame transformation can be observed intuitively, and the movement of the follower moves according to a given S-δ curve. In addition, in order to facilitate comparison and understanding, the teaching aid should also be able to demonstrate the movement of the original cam mechanism before the reversal.

5. The present invention has beautiful appearance and low manufacturing cost, and can be used as a special teaching aid to be extended to various colleges and universities.

The present invention will be described in further detail below with reference to the accompanying drawings and examples.

Description of drawings

Fig. 1 is a structural schematic diagram of the present invention.

FIG. 2 is a schematic diagram of the structure of FIG. 1 rotated by a certain angle.

Fig. 3 is a schematic structural view of the present invention after removing the frame and the drawing board.

FIG. 4 is a schematic diagram of the structure of FIG. 3 rotated by a certain angle.

Figure 5 is a side view of the present invention.

Explanation of reference signs:

1—drawing board; 1-1—angle scale; 2—follower;

2-1—the first slider; 3—cross bracket; 4—sun gear;

5—lock tooth plate; 6—rack plate; 6-1—second slider;

6-2—slide rail; 7—curved groove; 8—pin;

9—bottom shaft gear; 10—external shaft gear; 11—side shaft gear;

12—inner shaft gear; 13—inner shaft; 14—outer shaft;

15—sliding shaft; 16—side shaft; 17—second handle;

18—first handle; 19—bottom shaft; 20—frame;

21—Painting brush.

detailed description

As shown in Figures 1 to 5, the present invention includes a frame 20, an outer shaft 14, an inner shaft 13 and a drawing board 1, the drawing board 1 is arranged on the front side of the frame 20, the drawing board 1 is a transparent board, and the drawing board 1 is a transparent board. A cross bracket 3 is arranged between the drawing board 1 and the frame 20, and the bottom shaft 19 is installed on the bottom of the frame 20, and the bottom shaft gear 9 is fixedly installed on the bottom shaft 19, and the outer shaft 14 is a hollow shaft. , the outer shaft 14 passes through the front side of the frame 20 and the cross bracket 3 and is rotatably connected with the frame 20, the outer shaft 14 is fixedly connected with the cross bracket 3, and the outer shaft gear is fixedly installed on the outer shaft 14 10. Both the outer shaft gear 10 and the bottom shaft gear 9 are arranged in the frame 20, the outer shaft gear 10 is located above the bottom shaft gear 9 and meshed with the bottom shaft gear 9, the two ends of the inner shaft 13 Pass through the two ends of the outer shaft 14 respectively, the inner shaft 13 is rotationally connected with the outer shaft 14, the rear end of the inner shaft 13 passes through the frame 20 and is rotationally connected with the frame 20, and the drawing board 1 is fixedly mounted on The front end of the inner shaft 13 is fixedly mounted with a central gear 4 on the inner shaft 13 between the drawing board 1 and the cross bracket 3, and the upper front side of the cross bracket 3 is provided with a driven drive that can slide vertically along the cross bracket 3. 2, the lower front side of the follower 2 is provided with a brush 21, the lower part of the follower 2 is fixed with a pin 8, and a rack plate 6 is provided between the follower 2 and the cross bracket 3 And the rack plate 6 can slide horizontally along the cross bracket 3, the rack plate 6 has a curved groove 7, the pin 8 passes through the curved groove 7, the rack plate 6 is located above the central gear 4 and Meshes with the sun gear 4. In this embodiment, the inner shaft 13 is rotationally connected with the outer shaft 14 through a built-in bearing, both the inner shaft 13 and the outer shaft 14 can rotate, the cross bracket 3 can rotate together with the outer shaft 14, and the central gear 4 can rotate together with the inner shaft 13 The shape of the curved groove 7 is the S-δ curve of a given follower, the direction of the δ axis is the direction of the rack index line, the direction of the S axis is perpendicular to the direction of the δ axis, and the sliding direction of the rack plate 6 is the same as the direction of the δ axis , the follower 2 is driven to slide up and down by the pin 8 and the curved groove 7, and the sliding direction of the follower 2 is the same as the direction of the S axis.

As shown in Fig. 1, Fig. 3, Fig. 4 and Fig. 5, the top of described frame 20 is equipped with locking tooth plate 5 through slide shaft 15, and described slide shaft 15 is fixed on the frame 20, and described slide shaft 15 The number is two and the two sliding shafts 15 are parallel, the sliding shaft 15 is arranged above the inner shaft 13, the locking tooth plate 5 is located in the frame 20, the sliding shaft 15 passes through the locking tooth plate 5 and The locking tooth plate 5 can slide forward and backward along the sliding shaft 15 , and the locking tooth plate 5 cooperates with the outer shaft gear 10 .

As shown in Figures 2 to 5, the present invention also includes a side shaft 16, the front end of the side shaft 16 passes through the upper part of the frame 20 and is rotatably connected with the frame 20, and the side shaft 16 is parallel to the inner shaft 13 , the side shaft gear 11 is fixedly installed on the side shaft 16, the inner shaft gear 12 is fixedly installed on the inner shaft 13, the inner shaft gear 12 and the side shaft gear 11 are all located in the frame 20, the inner shaft gear 12 The shaft gear 12 meshes with the side shaft gear 11 , and the inner shaft gear 12 is located below the locking tooth plate 5 and cooperates with the locking tooth plate 5 .

As shown in FIG. 2 to FIG. 5 , the rear end of the bottom shaft 19 is fixedly connected with a first handle 18 , and the rear end of the side shaft 16 is fixedly connected with a second handle 17 for easy rotation.

As shown in Figures 1 to 5, the follower 2 is a slide rail, and the upper end of the front side of the cross bracket 3 is fixed with a first slider 2-1, and the first slider 2-1 is connected with the driven 2, the number of the first sliders 2-1 is two, and the two first sliders 2-1 are symmetrically arranged up and down.

As shown in Figure 2, Figure 4 and Figure 5, the rear side of the rack plate 6 is fixed with a second slider 6-1, the front side of the cross bracket 3 is fixed with a slide rail 6-2, the slide The rail 6-2 cooperates with the second slider 6-1.

As shown in FIGS. 1 to 5 , gear teeth are provided on the lower edge of the rack plate 6 , and the number of teeth on the lower edge of the rack plate 6 is greater than the number of teeth on the rim of the central gear 4 .

In this embodiment, the outer shaft 14 passes through the center of the cross bracket 3 .

In this embodiment, the centerlines of the outer shaft 14 and the inner shaft 13 coincide.

As shown in FIG. 1 , the shape of the drawing board 1 is circular, and an angle scale 1 - 1 is arranged on the outer periphery of the drawing board 1 to facilitate observation of the rotation angle.

The working principle of the present invention is: the present invention can be used to demonstrate the demonstration of drawing the cam profile curve by the reverse method and the movement of the original mechanism before the reverse. When the reverse method is used to draw the cam profile curve, the locking tooth plate 5 is slid to mesh with the inner shaft gear 12, and the sun gear 4 is fixed and relatively fixed with the frame 20. Turn the first handle 18 to drive the bottom shaft 19 to rotate, and the bottom shaft 19 drives the bottom shaft gear 9 to rotate. Because the outer shaft gear 10 meshes with the bottom shaft gear 9, the outer shaft gear 10 rotates, driving the outer shaft 14 and the cross bracket 3 together Rotation: Since the cross bracket 3 is slidingly connected with the rack plate 6, the rack plate 6 can be driven to rotate around the central gear 4 at the same speed. Simultaneously, because the rack plate 6 is meshed with the central gear 4, and the rack plate 6 is slidingly connected with the cross bracket 3, so the rack plate 6 moves linearly relative to the cross bracket 3 while following the rotation of the cross bracket 3, thus The movement in the direction of the δ axis of the S-δ curve is formed, and the displacement is linearly related to the rotation angle of the cross bracket 3 . According to the characteristics that the rack plate 6 is meshed with the central gear 4, when the rack plate 6 rotates one revolution, the displacement of the rack plate 6 is equal to the index circle circumference of the central gear 4. Since the span of the curved groove 7 along the indexing line of the rack plate is equal to the indexing circumference of the sun gear 4, the follower moves from one end of the curved groove to the other when the rack plate rotates one revolution. On the other hand, while the rack plate 6 moves linearly relative to the cross bracket 3, it drives the follower 2 to move linearly relative to the rack plate 6 through the curved groove 7, thus forming an S-δ curve in the direction of the S axis. The law of motion relative to the rack plate 6 is determined by the curved shape of the curved groove 7, that is, determined by a given S-δ curve. When the cross bracket 3 rotates one circle, the rack plate 6 rotates around the central gear 4 for one circle, and the follower 2 moves from one end of the curved groove 7 to the other end, and it completes the rotation along the δ axis relative to the rack plate 6. Linear motion and linear motion along the S-axis direction, wherein the motion along the δ-axis direction is linearly related to the rotation angle of the cross bracket 3, and the motion along the S-axis direction is carried out according to a given S-δ curve. Therefore, the drawing board 1 walks The passed track is the cam profile curve. During the actual demonstration, the process of drawing the cam profile curve and the drawn cam profile curve can be observed on the drawing board 1.

When used for the demonstration of the movement of the original mechanism before reversing, slide the locking tooth plate 5 to mesh with the outer shaft gear 10, turn the second handle 17, and drive the side shaft 16 to rotate, and the side shaft 16 drives the side shaft gear 11 to rotate, so The internal shaft gear 12 meshes with the side shaft gear 11, so the internal shaft gear 12 rotates to drive the central gear 4 and the drawing board 1 to rotate. The central gear 4 drives the rack plate 6 to move linearly along the δ-axis direction, and drives the follower 2 to move linearly along the S-axis through the curved groove 7 and the pin 8 . The central gear 4 rotates one circle, the cam profile curve on the drawing board 1 is formed, and the follower 2 returns to the original position after moving a stroke. During the actual demonstration, it can be observed that the movement of the follower 2 proceeds according to a given S-δ curve, and the track that the paintbrush 21 on the follower 2 walks on the drawing board 1 is a cam profile curve.

The above are only preferred embodiments of the present invention, and do not limit the present invention in any way. Any simple modifications, changes and equivalent structural transformations made to the above embodiments according to the technical essence of the present invention still belong to the technology of the present invention. within the scope of protection of the scheme.

Claims (10)

1. Cam profile curve draw a demonstrator, it is characterized in that: comprise frame (20),Outer shaft (14), interior axle (13) and drawing board (1), described drawing board (1) is arranged on frame (20)Front side, described drawing board (1) is transparent panel, between described drawing board (1) and frame (20) arrangeHave cross frame (3), the bottom of described frame (20) is rotatablely equipped with lower shaft (19), described inOn lower shaft (19), be installed with lower shaft gear (9), described outer shaft (14) is hollow shaft, instituteState outer shaft (14) through front side and the cross frame (3) of frame (20) and turn with frame (20)Be dynamically connected, described outer shaft (14) is fixedly connected with cross frame (3), on described outer shaft (14)Be installed with outer shaft gear (10), described outer shaft gear (10) and lower shaft gear (9) are all establishedPut in frame (20), described outer shaft gear (10) be positioned at lower shaft gear (9) top and with the endShaft gear (9) is meshed, and the two ends of described interior axle (13) pass respectively the two ends of outer shaft (14),Described interior axle (13) is rotationally connected with outer shaft (14), and the rear end of described interior axle (13) is through frame(20) and with frame (20) be rotationally connected, described drawing board (1) is fixedly mounted on interior axle (13)Front end, be positioned on the axle (13) between drawing board (1) and cross frame (3) and be installed withCentral gear (4), the front upper lateral part of described cross frame (3) is provided with can be along cross frame(3) driven member (2) vertically sliding, the lower front side of described driven member (2) is provided with paintbrush(21), the bottom of described driven member (2) is fixed with pin (8), described driven member (2) withBetween cross frame (3), be provided with rack-plate (6) and rack-plate (6) can be along cross frame(3) horizontal slip, has curved groove (7) on described rack-plate (6), described pin (8) is wornCross curved groove (7), described rack-plate (6) is positioned at central gear (4) top and and central gear(4) be meshed.
2. 2. draw demonstrator according to cam profile curve claimed in claim 1, it is characterized in that:The top of described frame (20) is provided with lock tooth plate (5), described slide-bar (15) by slide-bar (15)Be fixed on frame (20) upper, the quantity of described slide-bar (15) is two and two slide-bars (15) phaseParallel, described slide-bar (15) is arranged on interior axle (13) top, and described lock tooth plate (5) is positioned at machineIn frame (20), described slide-bar (15) can be along cunning through lock tooth plate (5) and lock tooth plate (5)Before and after axle (15), slide, described lock tooth plate (5) matches with outer shaft gear (10).
3. 3. draw demonstrator according to cam profile curve claimed in claim 2, it is characterized in that:Also comprise side shaft (16), the front end of described side shaft (16) is through top and and the machine of frame (20)Frame (20) is rotationally connected, and described side shaft (16) parallels with interior axle (13), described side shaft (16)On be installed with side shaft gear (11), on described interior axle (13), be installed with interior shaft gear (12),Described interior shaft gear (12) and side shaft gear (11) are all positioned at frame (20), described interior axle toothWheel (12) is meshed with side shaft gear (11), and described interior shaft gear (12) is positioned at lock tooth plate (5)Below and with lock tooth plate (5) match.
4. 4. draw demonstrator according to cam profile curve claimed in claim 3, it is characterized in that:The rear end of described lower shaft (19) is fixedly connected with first handle (18), after described side shaft (16)End is fixedly connected with second handle (17).
5. 5. draw demonstrator according to the cam profile curve described in the arbitrary claim of claim 1-4,It is characterized in that: described driven member (2) is slide rail, the upper end, front side of described cross frame (3) is solidSurely have the first slide block (2-1), described the first slide block (2-1) matches with driven member (2), described inThe quantity of the first slide block (2-1) is two, and two the first slide blocks (2-1) are symmetrical arranged up and down.
6. 6. draw demonstrator according to the cam profile curve described in the arbitrary claim of claim 1-4,It is characterized in that: the rear side of described rack-plate (6) is fixed with the second slide block (6-1), described crossThe front side of support (3) is fixed with slide rail (6-2), described slide rail (6-2) and the second slide block (6-1)Match.
7. 7. draw demonstrator according to the cam profile curve described in the arbitrary claim of claim 1-4,It is characterized in that: the lower edge of described rack-plate (6) is provided with the gear teeth, under described rack-plate (6)Gear teeth quantity on edge is greater than central gear (4) the wheel rim gear teeth quantity of one week.
8. 8. draw demonstrator according to the cam profile curve described in the arbitrary claim of claim 1-4,It is characterized in that: described outer shaft (14) is through the center of cross frame (3).
9. 9. draw demonstrator according to the cam profile curve described in the arbitrary claim of claim 1-4,It is characterized in that: the center line of described outer shaft (14) and interior axle (13) coincides.
10. 10. draw demonstrator according to the cam profile curve described in the arbitrary claim of claim 1-4,It is characterized in that: described drawing board (1) be shaped as circle, the periphery of described drawing board (1) is provided withAngle index (1-1).