Adjustable toggle rod power flexible driving device

Abstract

The invention discloses an adjustable toggle rod power flexible driving device which comprises a toggle rod mechanism, the toggle rod mechanism is composed of a crank rocker mechanism and a connecting rod sliding block mechanism, the crank rocker mechanism comprises a crankshaft, a push rod and a rocker, and the connecting rod sliding block mechanism comprises a connecting rod connected with the push rod and the rocker at the same hinge point and a sliding block connected with the connecting rod. The mechanism is characterized in that the speed curve regular change of the stroke of the sliding block is realized by adjusting the position or length of the fulcrum of the rocker, so that the flexible change of the stroke of the sliding block is realized. Compared with a slider-crank mechanism in the prior art, the adjustable toggle rod power flexible driving device provided by the invention has the advantages that the movement law design of the slider is more flexible and meets specific processing requirements, and movement laws with different requirements are obtained by adjusting the position of the rocker.

Description

Technical Field

[0001] The present invention relates to the field of forming equipment, and in particular to an adjustable toggle power flexible drive device. Background Art

[0002] The mechanism adopted by traditional forming machines is a crank-slider mechanism, which is a simple four-bar mechanism composed of four components: a crankshaft, a slider, a connecting rod, and a frame, as Figure 1 shown. Its motion law can be expressed as:

[0003] s = (R + L) - (Rcosα + Lsinβ)

[0004] The motion law is plotted as a motion curve as Figure 2 shown.

[0005] Its main characteristics are: the motion stroke is 2 times the crank length R; within one cycle of motion, when approaching the end position of the motion, the speed slows down, and when the stroke is 0, the speed is 0; then it immediately moves in the reverse direction, and the speed gradually increases, without staying at the end position of the stroke; when the structural parameters are determined, the stroke cannot be changed or adjusted during use.

[0006] However, in the field of mechanical manufacturing, the current quality requirements for products are continuously increasing, while the batch production quantity is decreasing, the mass production situation is changing, and the variety of products is increasing.

[0007] For the cold heading technology belonging to near-net shape machining, it is required that one-time cold heading forming can meet the accuracy requirements of products, without the need for subsequent supplementary processing, while improving productivity, reducing production costs, and enhancing competitiveness. The accuracy control of cold heading products is often due to the elastic deformation caused by the energy accumulation during material deformation at the end of the upsetting operation of traditional forming machines, which affects the final accuracy of the workpiece. Prolonging the sizing time during the upsetting process and releasing the deformation energy are important measures to control the recovery and springback of elastic deformation and ensure accuracy.

[0008] To meet the cold heading requirements of parts with the same specifications but different lengths, traditional cold heading processing can only be completed by selecting different forming machines, respectively selecting standard, extended, and extra-long models for processing, which requires purchasing different machines, increasing equipment investment and floor area, thereby increasing the manufacturing cost. Summary of the Invention

[0009] The purpose of the present invention is to provide an adjustable toggle power flexible drive device with high quality, high precision, and high economy to meet the processing needs of parts with the same specifications but different lengths in order to solve the above-mentioned deficiencies of the prior art.

[0010] An adjustable toggle power flexible drive device provided by the present invention includes a toggle mechanism, and the toggle mechanism is composed of a crank-rocker mechanism and a connecting rod-slider mechanism. The crank-rocker mechanism includes a crankshaft, a push rod and a rocker. The connecting rod-slider mechanism includes a connecting rod connected to the push rod and the rocker at the same hinge point and a slider connected to the connecting rod. The crankshaft and the push rod drive the rocker to swing, and then drive the connecting rod and the slider to move at the same hinge point. The characteristic is that by adjusting the position or length of the rocker fulcrum, the speed curve law of the slider stroke changes, so as to realize the flexible change of the slider stroke.

[0011] The position and length of the rocker fulcrum realize the speed curve law of the slider stroke, and its curve law conforms to the following operation formula:

[0012] For the needs of analytical method analysis and numerical solution method, the position of the common hinge point of the three rods of the rocker, the push rod and the connecting rod is set as the coordinate origin O, the moving direction of the slider is the positive direction of the X axis, the coordinate system is configured according to the right-hand rule, and the coordinates of the remaining hinge points are in this coordinate system. The clockwise rotation angle of the active crankshaft relative to the negative y-axis direction is θ, relative to the support O 0 makes a rotational motion, then the hinge point O 1 on the crank has the following motion relationship:

[0013] x 1 = x 0 -Rsinθ (1)

[0014] y 1 = y 0 -Rcosθ (2)

[0015] and

[0016] (x 1 - x 0 ) 2 +(y 1 - y 0 ) 2 = R 2 (3)

[0017] The common hinge point O 3 of the three rods swings relative to the support O 1 of the rocker L 2 and moves under the action of the push rod L 3 , and L 3 itself makes a planar motion, then there is:

[0018]

[0019] The hinge point O 3 pulls the connecting rod to drive the slider to make a reciprocating motion on the X axis, and its motion law is:

[0020]

[0021] Set the position of the slider at the front dead center as the starting point, then the movement stroke is

[0022]

[0023] In the formula: R is the crank length;

[0024] L 1 is the rocker length;

[0025] L 2 is the connecting rod length;

[0026] L 3 is the push rod length;

[0027] S is the slider stroke, the position from the front dead center;

[0028] x 0 、y 0 are the coordinates of the crank support O 0 ; O 0 is set on the y-axis, y 0 = 0;

[0029] x 1 、y 1 are the coordinates of the hinge point O 1 between the crank and the push rod;

[0030] x 2 、y 2 are the coordinates of the support point O 1 of the rocker L 2 ;

[0031] x 3 、y 3 are the coordinates of the three-bar connection hinge point O 3 between the push rod, the rocker and the connecting rod;

[0032] x 4 、y 4 are the coordinates of the hinge point O 4 between the connecting rod and the slider; the slider moves on the x-axis and y 4 = 0;

[0033] Qualitatively analyze the motion law of the toggle forming machine for this layout, and briefly explain the high-precision machining provided by this structure forming machine and its flexible characteristics of meeting different length requirements through adjustment.

[0034] During a motion cycle, when the crankshaft of the driving member starts or ends its motion, the crankshaft is in the lower position. When the crankshaft rotates by a certain angle, the displacement change amounts Δx and Δy generated in the X-axis direction and Y-axis direction are small, and the change amount Δy is much smaller than Δx. The crankshaft is the shortest member in this linkage structure, and this motion is transmitted to the hinge point O of the three rods through the push rod. 3 .

[0035] The push rod coincides with the Y-axis in the initial position. When the crank rotates, the connecting end of the push rod and the crank changes with the motion of the crankshaft and deviates from the Y-axis. Since the change amount Δy of the crankshaft rotation is much smaller than Δx, the movement of the push rod in the Y-axis direction is very small and can be ignored. The change of Δx only causes a slight offset of the lower end of the push rod relative to the Y-axis and a relatively small rotation angle. At the same time, the length of the push rod is also greater than the length of the crank. The upper end of the push rod is restricted by the rocker and pushes the rocker to rotate. The change of Δx has a very limited effect on the motion of the rocker.

[0036] The rocker is in the horizontal position in the initial position. The swing of the rocker is driven by the movement amount in the Y direction of the fulcrum O 3 . The change amount Δy of the push rod acting on this point hardly changes, and the change amount from Δx causes the push rod to deflect, making the change amount of point O 3 in the Y direction even smaller. To put it another way, the swing of the rocker is in the vertical direction, and its rod length is greater than the length of the crank. The change of Δy of point O 1 caused by the change of Δx at point O 3 is extremely small.

[0037] It can be seen that the rotation of the driving member crankshaft in the horizontal direction drives the swing of the rocker in the vertical direction through the transmission of the push rod with little effect and can be ignored. This ensures that the crankshaft stays when it reaches the dead center position, forcing its upsetting force to act on the product continuously and efficiently, enabling the cold-heading product to be fully pressed, reducing the springback effect caused by the accumulation of internal deformation energy in the product, eliminating the springback, and thus improving the quality and accuracy of the product. Meeting the requirements of high-precision machining.

[0038] From the working stroke relationship formula (7) of the slider, the main factor affecting the working stroke s of the slider is the absolute value of x 3 , which is the key point of the variable stroke operation and the core of the flexible forming machine realized by the present invention.

[0039] Without changing the composition of the forming machine mechanism and the given rod lengths, move the support seat of the rocker downward, and the position of the common hinge point of the three rods (rocker, push rod, and connecting rod) remains unchanged. When the crankshaft rotates, the push rod acts on O 3The effect of the point is significantly enhanced, causing the initial angle of the rocker relative to the horizontal line to increase from the original 0° as the downward displacement increases, accelerating the horizontal displacement, thereby changing the x value when the slider reaches the dead center, and increasing the stroke of the slider. This method can conveniently change the stroke of the forming machine, thus meeting the requirement of variable-stroke processing and achieving the goal of structural flexibility. 3 The numerical verification of the dwell operation during upsetting when the slider reaches the front dead center and the variable-stroke characteristics generated by changing the position of the rocker hinge support is further specifically described by the calculated data and charts in the embodiments.

[0040] The adjustable toggle power flexible drive device provided by the present invention drives the rocker, connecting rod, and slider to move by the crank; the movement of the connecting rod and slider is restricted and adjusted by the rocker, changing the movement form of the slider; compared with the existing crank-slider mechanism, two additional rods are added to form a new rod system structure, thereby providing flexibility in the design of the motion law. For specific processing requirements, different motion laws can be obtained by adjusting the rod lengths and positions.

[0041] The present invention can be implemented by only changing the position of the rocker support point without changing the length of the rocker, keeping the lengths and original positions of the other rods unchanged, and increasing the slider stroke as the rocker position moves downward; by setting a longer dwell time at the front dead center position of the slider to continuously extrude the part. The law of changing the rocker position to increase the slider stroke is to change the position of the rear dead center of the slider stroke, while keeping the position of the front dead center unchanged. Thus, it does not affect or change the installation and connection of the mold, does not affect the upsetting state, does not change the position of the front dead center of the slider stroke, does not require changing and adjusting other working mechanisms of the cold heading machine, and does not affect the functions and working performances of the feeding mechanism, shearing mechanism, and gripper feeding mechanism. The law of changing the rocker position to change the slider motion law is that the dwell time of the slider at the front dead center position shortens as the downward displacement of the rocker position increases, while the speed during its subsequent movement increases.

[0042] The present invention adopts a toggle structure and is applied to forming machine equipment. Especially at the end position of upsetting, under the continuous action of a strong upsetting force, the internal stress generated by upsetting in the product is fully released, reducing deformation springback and improving manufacturing accuracy; at the same time, by adjusting the position or length of the rocker fulcrum, the stroke of the slide table is changed, meeting the forming processing requirements of different length parts on the same machine. This device is especially suitable for the production needs of high-precision, multi-variety, and small-batch products in forming equipment, reducing equipment investment, and improving equipment utilization and production economy.

[0043] Brief description of the drawings Sketch of the crank-slider mechanism

[0044] Figure 1

[0045] Figure 2 The variation law of the motion stroke of the crank-slider mechanism with the crank angle;

[0046] Figure 3 The schematic diagram of the motion mechanism of the toggle forming machine;

[0047] Figure 4 The motion law of the toggle mechanism in the in-situ state;

[0048] Figure 5 The basic structure diagram of the toggle structure forming machine;

[0049] Figure 6 The motion law of the toggle mechanism when the rocker arm moves down 50 mm;

[0050] Figure 7 The motion law of the toggle mechanism when the rocker arm moves down 100 mm;

[0051] Figure 8 The motion law of the toggle mechanism when the rocker arm moves down 148 mm;

[0052] Figure 9 The comparison diagram of the toggle mechanism when the rocker arm has different downward displacements;

[0053] Figure 10 Implement the flexible adjustment scheme of the rocker arm;

[0054] Figure 11 The fixed two-point adjustment scheme of the rocker arm support;

[0055] Figure 12 The structural scheme of arbitrary adjustment of the push rod support;

[0056] Figure 13 The situation of arbitrary adjustment positions of the rocker arm support;

[0057] Figure 14 The change of the slider's after-dead center position when the rocker arm support is adjusted at two fixed positions;

[0058] Figure 15 The change of the slider's after-dead center position when adjusted at two positions under arbitrary adjustment of the rocker arm support. Specific implementation manner

[0059] The following is a description of the preferred embodiments of the present invention in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0060] Embodiment 1.

[0061] An adjustable toggle power flexible drive device provided in this embodiment includes a toggle mechanism, and the toggle mechanism is composed of a crank-rocker mechanism and a connecting rod-slider mechanism. The crank-rocker mechanism includes a crankshaft, a push rod, and a rocker. The connecting rod-slider mechanism includes a connecting rod connected to the push rod and the rocker at the same hinge point and a slider connected to the connecting rod. The crankshaft and the push rod drive the rocker to swing, and then drive the connecting rod and the slider to move at the same hinge point. By adjusting the position or length of the rocker fulcrum, the speed curve law of the slider stroke is changed, so as to realize the flexible change of the slider stroke.

[0062] The position and length of the rocker fulcrum realize the speed curve law of the slider stroke, and its curve law conforms to the following operation formula:

[0063] For the needs of analytical method analysis and numerical solution method, the position of the common hinge point of the three rods of the rocker, the push rod and the connecting rod is set as (at) the coordinate origin O, the moving direction of the slider is the positive direction of the X axis, the coordinate system is configured according to the right-hand rule, and the coordinates of the remaining hinge points (see the Figure 3 illustrated embodiment) In this coordinate system, the clockwise rotation angle of the active crankshaft relative to the negative y-axis direction is θ, relative to the support O 0 makes a rotational motion, then the hinge point O 1 on the crank has the following motion relationship:

[0064] x 1 = x 0 -Rsinθ (1)

[0065] y 1 = y 0 -Rcosθ (2)

[0066] and

[0067] (x 1 -x 0 ) 2 +(y 1 -y 0 ) 2 = R 2 (3)

[0068] The common hinge point O 3 of the three rods swings relative to the support O 1 of the rocker L 2 and moves under the action of the push rod L 3 , and L 3 itself makes a planar motion, then there is:

[0069]

[0070] The hinge point O 3 pulls the connecting rod to drive the slider to make a reciprocating motion on the X axis, and its motion law is:

[0071]

[0072] Set the slider at the position of the front dead center (L 2 , 0) as the starting point, then the motion stroke is

[0073]

[0074] For the schematic diagram of the toggle forming machine with this layout ( Figure 3 ), qualitatively analyze its motion law, and briefly explain the high-precision machining provided by this structure forming machine and its flexible characteristics of meeting different length requirements through adjustment.

[0075] In a motion cycle, when the crankshaft, the driving part, starts or ends its motion, the crankshaft is in the lower position. When the crankshaft rotates through a certain angle, the displacement change amounts Δx and Δx generated in the X-axis direction and Y-axis direction are small, and the change amount Δy is much smaller than Δx. The crankshaft is the shortest component in this linkage structure, and this motion is transmitted to the hinge point O of the three-link by the push rod 3 .

[0076] The push rod coincides with the Y-axis at the initial position. When the crank rotates, the connecting end of the push rod and the crank changes with the motion of the crankshaft and deviates from the Y-axis. Since the change amount Δy of the crankshaft rotation is much smaller than Δx, the movement of the push rod in the Y-axis direction is very small and can be ignored. The change of Δx only causes a small offset of the lower end of the push rod relative to the Y-axis and rotates through a very small angle. At the same time, the length of the push rod is also greater than the length of the crank. The upper end of the push rod is restricted by the rocker and pushes the rocker to rotate. The change of Δx has a very limited effect on the motion of the rocker.

[0077] The rocker is in the horizontal position at the initial position. The swing of the rocker is driven by the displacement in the Y direction of the fulcrum O 3 . The change amount Δy of the push rod acting on this point hardly changes, and the change amount from Δx causes the push rod to deflect, making the change amount of point O 3 in the Y direction even smaller. To put it another way, the swing of the rocker is in the vertical direction, and its rod length is greater than the length of the crank. The change of Δy generated by the change of Δx at point O 1 is negligible. 3

[0078] It can be seen that the rotation of the driving part crankshaft in the horizontal direction drives the rocker to swing in the vertical direction through the transmission of the push rod with little effect and can be ignored. This ensures that the crankshaft stays when it reaches the dead center position, forcing its upsetting force to act continuously and efficiently on the workpiece, enabling the cold upset workpiece to be fully pressed, reducing the springback effect caused by the accumulation of internal deformation energy in the workpiece, eliminating springback, and thus improving the quality and precision of the workpiece. Meeting the requirements of high-precision machining.​

[0079] Obtained from the slider working stroke relational expression (7), the main factor affecting the slider working stroke s is the absolute value of x 3 , which is the key point of the variable-stroke operation and the core of the flexible forming machine implemented by the present invention.

[0080] Without changing the composition of the forming machine mechanism and the given rod lengths, move the support seat of the rocker arm downward, and the position of the common hinge point of the three rods (rocker arm, push rod, and connecting rod) remains unchanged. When the crankshaft rotates, the effect of the push rod on point O 3 is significantly enhanced, causing the initial angle of the rocker arm relative to the horizontal line to increase from the original 0° as the downward displacement increases, accelerating the horizontal displacement, thereby changing the x value when the slider reaches the rear dead point, and increasing the stroke of the slider. This method can conveniently change the stroke of the forming machine, thus meeting the requirements of variable-stroke processing and achieving the goal of structural flexibility.

[0081] Regarding the numerical verification of the dwell operation during upset forging when the slider reaches the front dead point and the variable-stroke characteristics generated by changing the position of the rocker arm hinge support, it is further specifically illustrated by the calculated data and charts in the embodiments.

[0082] This embodiment is the simplest and most basic toggle structure arrangement.

[0083] The rocker arm support O 2 is arranged on the X-axis. At this time,

[0084] L 1 = H 1 = -x 2 (8)

[0085] H 2 = y 2 = 0 (9)

[0086] From the support coordinates O 2 (-L 1 , 0)

[0087] Given the lengths of the rods of the toggle mechanism and the rotation angle of the active crankshaft with specific data, according to formulas (1) to (7), when the crankshaft is at different angular positions, first calculate the coordinate values x 1 and y 1 of point O 1 , then calculate the coordinate values x 3 and y 3 of the hinge point O 3 , and finally calculate the coordinate values x 4 and y 4 and y 4 of the point O 4 where the connecting rod is on the slider, and then the stroke s value of the slider can be obtained.

[0088] When the hinge points of the three rods at the initial position are at the origin of coordinates, given the length data of each rod, the displacement change law under the given conditions can be directly obtained. Given the rod lengths R, L 1 , L 2 , L 3 being 100 mm, 400 mm, 350 mm, and 425 mm respectively, and at the same time, when the crankshaft is taken at equal intervals of 10° in a cycle from 0° to 360° for calculation, the motion displacement curve of the slider is plotted as Figure 4 shown.

[0089] Figure 4 Main characteristics of the curve:

[0090] 1. Figure 4 The curve has a different shape from the stroke curve of the crank-slider mechanism. The stroke curve of the crank-slider is wide and flat, while the stroke curve of the toggle mechanism is narrow and sharp.

[0091] 2. Under the same crank radius and connecting rod conditions, the maximum stroke of the crank-slider mechanism is twice the crank length, while the maximum displacement of the toggle mechanism is only approximately equal to the length of the connecting rod. And the maximum displacement of the toggle mechanism forming machine has no direct proportional relationship with the crank length, but is affected and restricted by the mutual influence of the lengths of the components constituting the toggle mechanism, and is obtained by comprehensive consideration of the specific composition relationship.

[0092] 3. At both ends of the stroke curve of the toggle mechanism, it is basically a horizontal straight line. Analyzing within one cycle, that is, in a relatively long period before and after the start and end of the upsetting operation, when the crankshaft rotates approximately within ±40° before and after the bottom dead center, the motion stroke of the slider is basically unchanged. The data shows that its stroke is less than 1 mm, and when operating at ±10°, the displacement is even less than 0.003 mm, which is equivalent to the surface roughness value of the component. The stay during this period continues to extrude the upset forgings, which is sufficient to dissipate most of the deformation energy accumulated during upsetting, reduce the elastic recovery of the material, and improve the product accuracy. While the slider displacement when the crank of the crank-slider mechanism rotates 10° is 1.88 mm, which is greater than the displacement of 1.83 mm when the crankshaft of the toggle mechanism rotates 50°. The stay and extrusion effect of the toggle mechanism is obvious.

[0093] 4. The upper part of the stroke curve of the toggle mechanism changes more steeply than the upper part of the crank mechanism. The slope of the stroke curve represents the speed, and the result means that the speed of the toggle mechanism when entering upsetting is faster than that of the crank mechanism, the impact kinetic energy generated on the product is greater, and the upsetting effect is better.

[0094] 5. Further in-depth analysis shows that when the toggle mechanism is at the extreme position where the crankshaft and the push rod form a straight line, the angles through which the crankshaft rotates in the left and right regions are different, and the time taken for the slider to retreat and advance is different. When the crankshaft rotates clockwise, the angle through which the slider retreats when the crankshaft rotates from the bottom dead center to the top dead center is smaller than the angle through which the slider advances when the crankshaft rotates from the top dead center back to the bottom dead center. The average speed of the slider during retreat is greater than that during advance, featuring fast retreat and slow advance.

[0095] Figure 5 It shows the basic structural form of the toggle mechanism forming machine. The rocker 2 and the crankshaft 5 are installed on the bed 1 through a hinge mechanism. The connecting rod 3 is connected to the rocker 2 and the push rod 6 at the same hinge, and the connecting rod 3 drives the slider 4 to slide on the guide rail of the bed 1.

[0096] When the crankshaft starts to rotate from the lowest position below, the crankshaft drives the push rod to make the common hinge point of the three rods move in an arc around the rocker 2 towards the upper left, driving the connecting rod 3 to perform a planar motion and making the slider 4 move left on the guide rail of the bed; when the crankshaft and the push rod form a straight line, the hinge point of the three rods reaches the highest point in the upper left (top dead center), and the slider retreats to the leftmost position (rear dead center); as the crankshaft continues to rotate, the hinge point of the three rods returns from the highest point and moves towards the lower right, and the slider starts to move right, entering the forward stroke of the upsetting operation; when the crankshaft rotates back to the lowest position and coincides with the push rod, the hinge point of the three rods is at the origin position of the coordinate, and the slider reaches the rightmost position (front dead center), which is the end position of the upsetting operation at this time.

[0097] The rotation of the crankshaft can be clockwise or counterclockwise. No matter which direction it rotates, the movement direction of the slider is the same. However, when the crankshaft and the push rod form a straight line, that is, when the hinge point of the three rods reaches the highest point (the crankshaft is at the top dead center) and the slider reaches the rear dead center, the angles rotated by clockwise rotation and counterclockwise rotation are different. The difference in the two angles is 2θ 0 , the angle rotated when rotating clockwise to reach the top dead center is 180° - θ 0 , the angle of counterclockwise rotation is 180° + θ 0 . The crankshaft rotates at a uniform speed. The longer the angle rotated, the longer the time taken, and the smaller the angle rotated, the shorter the time taken.

[0098] The distances of the forward stroke and the retreat stroke of the slider are the same. When the crankshaft rotates from the bottom dead center to the top dead center, the slider is in the retreat stroke, and when the crankshaft rotates from the top dead center back to the bottom dead center, it is the forward stroke of the slider. When the crankshaft rotates clockwise and reaches the top dead center, the time taken is small, the average speed of the retreat stroke of the slider is faster, and the average speed of the forward stroke during return is slower, which is the fast retreat and slow advance mode; conversely, when the crankshaft rotates counterclockwise, the movement mode of the slider is the slow retreat and fast advance mode.

[0099] Figure 4The results show that the slider stroke in this embodiment is 100 mm. When the slider is at the front dead center position and the crankshaft rotation angle is within ±10°, the displacement change is only 0.003 mm. It can be considered that the slider stays under the action of a strong upsetting force for a long time, ensuring sufficient time for deformation during upsetting, eliminating internal deformation stresses, and improving the quality of upsetting.

[0100] Embodiment 2:

[0101] In this embodiment, with all other conditions remaining completely unchanged, only the rocker support O 2 rotating around the hinge point O of the three rods 3 towards the lower left by a certain angle (position) is analyzed for the change in the maximum slider stroke and the residence time (phase angle) near the front dead center.

[0102] The rocker support O 2 rotates around the hinge point O of the push rod and other rods 3 towards the lower left, and the downward displacement amount is H 2 , then:

[0103]

[0104] At this time, the coordinates of the support O 2

[0105] The difference between this Embodiment 2 and Embodiment 1 is that the position coordinates of the rocker fulcrum change, and the lengths of the rods of the toggle mechanism remain unchanged. The rod lengths R, L 1 , L 2 , L 3 are 100 mm, 400 mm, 350 mm, and 420 mm respectively and remain unchanged.

[0106] To comprehensively and completely express the effects of position changes, different downward displacement amounts H 2 of 50 mm, 100 mm, and 148 mm are given respectively. According to formulas (1) to (7), the coordinate values x 2 and y 3 of the hinge point O of the crankshaft at different angular positions can be calculated, as well as the coordinate x 3 and the stroke s value of the slider. The displacement curves plotted are 3 , 4 and Figure 6 , Figure 7 and Figure 8 . By overlapping and plotting the slider motion displacement curves at different coordinate positions of the rocker of the toggle-type forming machine on Figure 9 , it can be more clearly felt the change in the maximum slider stroke and the residence situation at the end of upsetting caused by the position change of the rocker fulcrum.

[0107] The adjustment of the rocker installation position has the following main characteristics on the working state change of the slider:

[0108] 1. The shape of the slider stroke curve after the rocker moves downward is basically the same as that in Example 1, showing a relatively gentle curve at both ends, a certain period of stay at the front dead center position of the slider, and a rapid change in the middle part.

[0109] 2. The change of the displacement curve when the rocker moves downward is equivalent to stretching the top of the curve at the basic position. As the top rises (increasing the stroke), the bottom also gradually extends outward (decreasing the stay). This makes the two sides of the middle part of the curve steeper, with a faster acceleration; the top is sharper, and the change from deceleration to reverse acceleration is more rapid; the two sides of the bottom widen outward, indicating that the stay time before or after the front dead center of the slider is shortened.

[0110] 3. Numerically, when the rocker fulcrum moves downward from 0 mm to 50 mm, 100 mm, and 148 mm, the slider stroke increases from the initial 100 mm to 125.5 mm, 151.3 mm, and 176.9 mm respectively. The slider stroke increases nearly linearly with the increase of the downward displacement.

[0111] 4. The stay time caused by the curve change near the end of upsetting also changes. With the increase of the downward displacement, the stay time is correspondingly shortened. Analyzed numerically, even when the downward displacement is 148 mm, compared with the crank-slider mechanism with the same stroke data, the stay time is more than twice as long, and the effect is still very obvious.

[0112] 5. The downward movement of the rocker fulcrum changes the shape of the slider motion curve, adjusts state parameters such as the motion stroke and the stay time at the front dead center during upsetting, which is conducive to reasonably distributing the working cycle and formulating the working cycle diagram of the cold heading operation; appropriate adjustment of each actuator is more conducive to realizing the coordination and optimization of each actuator and motion of the forming machine.

[0113] To realize the adjustment of the rocker support point of the toggle press forming machine, its support is separated from the bed and made into a movable independent structure. Figure 10 The structural member 7 shown is the rocker support seat of the adjustable toggle mechanism. It is independent of the bed, and other structures are the same as the basic structure.

[0114] There are many adjustment methods for the rocker support, which are selected according to requirements in practice. Figure 11 This is an adjustment method with a fixed adjustment point position, combined with the Figure 10 structure, moving from one fixed point to another fixed point to change the working stroke of the forming machine. This working stroke is pre-determined by design and processed into the corresponding connection and fixing method. The inverted "L" structure on the support is used to position and bear the weight of the support.

[0115] Figure 12 and Figure 13 represents the supporting point of the rocker, which is a structure form that can be adjusted arbitrarily. The support of the rocker can select a suitable point to be fixed within the given sliding surface to obtain the required upsetting stroke. The method is to adjust the position of the rocker support up and down along the inclined plane through a screw mechanism, and after determination, lock the screw mechanism and fix it on the bed.

[0116] Figure 14 and Figure 15 represent the supports of the rocker before and after adjustment at two different working positions, and the position states of each rod when the crankshaft is at the top dead center. When the position of the rocker moves down, the positions of each rod deviate to the left, and the position of the slider moves to the left. When the crankshaft is at the bottom dead center position, no matter what position the rocker is in, the position of the slider remains unchanged. The change in the slider stroke becomes larger in the direction of the idle stroke, and the position during upsetting remains unchanged. Without changing the structural composition or replacing components, the stroke of the forming machine can be changed, and after the change, it does not affect the upsetting state, the position of the fixed die base, the functions of the feeding mechanism, shearing mechanism, and clamp transfer mechanism that match the upsetting, nor does it affect the overall stress state and rigidity. Its degree of flexibility is high.

[0117] In this embodiment, only the position of the rocker support point is changed without changing the length of the rocker, and the lengths and original positions of the other rods remain unchanged. The slider stroke increases as the position of the rocker moves down; the part is continuously extruded by setting a longer dwell time at the front dead center position of the slider. The rule of changing the rocker position to increase the slider stroke is to change the rear dead center position of the slider stroke, and the front dead center position remains unchanged. Thus, it does not affect and change the installation and connection of the mold, does not affect the upsetting state, does not change the front dead center position of the slider stroke, does not need to change and adjust other working mechanisms of the cold heading machine, and does not affect the functions and working performances of the feeding mechanism, shearing mechanism, and clamp feeding mechanism. The rule of changing the slider motion law by changing the rocker position is that the dwell time of the slider at the front dead center position shortens as the downward displacement of the rocker position increases, and the speed during its subsequent movement increases.

[0118] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, for those skilled in the art, they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. An adjustable elbow lever power flexible driving device, comprising an elbow lever mechanism, the elbow lever mechanism is composed of a crank rocker mechanism and a connecting rod slider mechanism, the crank rocker mechanism comprises a crankshaft, a push rod and a rocker, the connecting rod slider mechanism comprises a connecting rod connected to the push rod and the rocker at the same hinge point and a slider connected to the connecting rod, the crankshaft and the push rod drive the rocker to swing, and then drive the connecting rod and the slider to move at the same hinge point, wherein the crankshaft and the push rod drive the rocker to swing, and then drive the connecting rod and the slider to move at the same hinge point, wherein the crankshaft and the push rod drive the rocker to swing, and then drive the connecting rod and the slider to move, wherein the crankshaft and the push rod drive the rocker to swing, and then drive the connecting rod and the slider to move at the same hinge point, and wherein the crankshaft and the push rod drive the rocker to swing, and then drive the connecting rod and the slider to move ... By adjusting the position or length of the rocker fulcrum, the speed curve of the slider stroke can be changed regularly, thereby achieving flexible change of the slider stroke.

2. The adjustable toggle power flexible drive device according to claim 1 is characterized in that The speed curve of the slider stroke conforms to the following calculation formula: For the needs of analytical analysis and numerical solution, the common hinge point of the rocker, push rod and connecting rod is set as the coordinate origin O, the movement direction of the slider is the positive direction of the X axis, and the coordinate system is configured according to the right-hand rule. The coordinates of the remaining hinge points are in this coordinate system. The clockwise rotation angle of the active component crankshaft relative to the negative y-axis direction is θ, and it rotates relative to the support O0. Then the motion relationship of the hinge point O1 on the crank is: x1=x0-Rsinθ (1) y1=y0-Rcosθ (2) and (x1-x0) 2 +(y1-y0) 2 =R 2 (3) The hinge point O3 shared by the three rods swings relative to the support O2 of the rocker L1, and moves under the action of the push rod L3, while L3 itself moves in a plane, then: The hinge point O3 traction connecting rod drives the slider to reciprocate on the X-axis, and its motion law is: Assuming the position of the slider at the front dead center as the starting point, the movement stroke is: in: R is the crank length; L1 is the length of the rocker; L2 is the connecting rod length; L3 is the length of the push rod; S is the slider stroke, the distance from the front dead center; x0, y0 are the coordinates of the crank support O0; O0 is set on the y-axis, y0=0; x1, y1 are the coordinates of the hinge point O1 between the crank and the push rod; x2, y2 are the coordinates of the support point O2 of the rocker L1; x3, y3 are the coordinates of the hinge point O3 of the three-bar connection of the push rod, rocker and connecting rod; x4 and y4 are the coordinates of the hinge point O4 between the connecting rod and the slider; the slider moves on the x-axis at y4=0.

3. The adjustable toggle power flexible drive device according to claim 1 is characterized in that Only the position of the rocker support point is changed without changing the length of the rocker, and the lengths and original positions of the other rods remain unchanged. The stroke of the slider increases as the position of the rocker moves downward.

4. The adjustable toggle power flexible drive device according to claim 1 is characterized in that The parts are continuously extruded by setting a longer dwell time of the slider at the front dead point.

5. The adjustable elbow-lever power flexible drive device according to claim 3 is characterized in that The rule for changing the rocker position to increase the slider stroke is to change the rear dead point position of the slider stroke, while the front dead point position remains unchanged.

6. The adjustable toggle power flexible drive device according to claim 3 is characterized in that The changing of the rocker position to change the movement law of the slider is that the residence time of the slider at the front dead point position is shortened as the downward displacement of the rocker position increases, while the speed of the slider in the subsequent movement is accelerated.

Images