Rear through structure of cam type forming machine

Abstract

The utility model discloses a rear through structure of a cam type forming machine, which comprises a rear through base and a rear through ejection rod mechanism, a rear through transmission shaft, a rocker arm shaft and a rocker arm reset mechanism are fixedly arranged on the rear through base, a rear through cam is arranged on the rear through transmission shaft, a rear through rocker arm is arranged on the rocker arm shaft, and a rear through ejection rod is arranged on the rear through rocker arm. The rear-through transmission shaft drives the rear-through cam to drive the rear-through rocker arm to push the rear-through ejection rod mechanism to operate according to the cam curve track of the rear-through cam, and the rocker arm reset mechanism comprises a rocker arm reset ejection rod and a rocker arm reset compression spring for pushing the rocker arm reset ejection rod. The rocker arm reset ejector rod enables the rear through rocker arm to be tightly attached to the rear through cam and enables the rear through ejector rod mechanism to be reset under the action of the rocker arm reset compression spring. A cam structure is adopted, circular motion is achieved, inertia is small, transmission efficiency is high, compared with an old-fashioned rear-through structure of connecting rod transmission, the transmission efficiency is greatly improved, and particularly, the rear-through cam drives a rear-through ejection rod mechanism to move together with a blank and a sliding table, and operation is stable and harmonious.

Description

Technical Field

[0001] This utility model relates to a forming machine production technology, and in particular to a cam-type forming machine rear passage structure. Background Technology

[0002] In existing technologies, most forming machines use a connecting rod to drive a rocker arm to achieve the discharge function in their rear-through structure. However, due to the structure of the connecting rod, the adjustment time of the rear-through structure during operation is relatively limited, making it difficult to meet the discharge requirements of complex parts. Furthermore, the reciprocating motion of the connecting rod has low transmission efficiency and high inertia, which is not conducive to high-efficiency upsetting production. At the same time, the push stroke law of the rear-through cam uses a commonly used motion curve, which causes motion lag or collision between the ejector rod and the workpiece during the rear-through operation. Utility Model Content

[0003] The purpose of this invention is to overcome the shortcomings of the above-mentioned technology by providing a cam-type forming machine rear passage structure with low inertia, high transmission efficiency, and suitable for complex parts.

[0004] To achieve the above objectives, the present invention provides a cam-type forming machine rear-through structure, which includes a rear-through base and a rear-through ejector mechanism. A rear-through drive shaft, a rocker arm shaft, and a rocker arm reset mechanism are fixedly mounted on the rear-through base. A rear-through cam is mounted on the rear-through drive shaft, and a rear-through rocker arm is mounted on the rocker arm shaft. The rear-through drive shaft drives the rear-through cam to drive the rear-through rocker arm to push the rear-through ejector mechanism along the cam curve trajectory of the rear-through cam. The rocker arm reset mechanism includes a rocker arm reset ejector rod and a rocker arm reset spring that pushes the rocker arm reset ejector rod. Under the action of the rocker arm reset spring, the rocker arm reset ejector rod makes the rear-through rocker arm fit tightly against the rear-through cam and resets the rear-through ejector mechanism.

[0005] The rear through-hole push rod mechanism includes a rocker arm push rod mounted on the rear through rocker arm, a long push rod fixed to the rear through base, a transition push rod, and a front push rod.

[0006] The rocker arm reset mechanism also includes a rocker arm reset spring seat for positioning the rocker arm reset top rod.

[0007] The rear-through cam includes a rear-through ejector cam and a rear-through tangential cam. The motion law of the tangential segment of the rear-through tangential cam is selected according to a sinusoidal law, and its relationship can be expressed as:

[0008]

[0009] in: It is the cam rotation angle of the tangent segment; δ is the tangent cam rotation angle, α is the crankshaft rotation angle, and h1 is the tangent stroke.

[0010] To reduce wear on the contact surfaces of the rear rocker arm and rocker arm push rod, rocker arm reset contact blocks are provided on the rear rocker arm and rocker arm push rod.

[0011] The cam-type forming machine rear-pass structure provided by this utility model has the following characteristics: During operation, the power driving the rear-pass cam is obtained from the main transmission of the forming machine crankshaft, which drives the rear-pass transmission shaft through a bevel gear. The rear-pass transmission shaft drives the rear-pass ejection cam and the rear-pass trimming cam to rotate. The rear-pass ejection cam and the rear-pass trimming cam are designed to move with the forming machine slider and meet the operational requirements; that is, the rear-pass cam ejection law of this utility model is selected and designed according to the requirements of the movement and clamping of the blank during rear-pass ejection to improve the quality of rear-pass ejection. During operation, the rear-pass cam drives the rocker arm to reciprocate, driving the rear ejector rod, long ejector rod, transition ejector rod and front ejector rod required for rear-pass ejection to move in advance, ejecting the blank or finished product in the fixed mold, realizing the rear-pass ejection function and the trimming function of the final station.

[0012] This utility model adopts a cam structure to realize the functions of rear-pass ejection and rear-pass trimming. The timing of the rear-pass action during one working cycle can be adjusted to meet the rear-pass requirements of complex parts. Since the cam drive is a circular motion with low inertia and high transmission efficiency, it greatly improves the transmission efficiency compared with the old linkage drive rear-pass structure, thereby improving the overall working efficiency of the machine.

[0013] The cam-type forming machine rear-pass structure provided by this utility model has a push stroke profile of the rear-pass cam designed according to the motion characteristics of the slide table, which avoids collision between the rear-pass ejector mechanism and the blank during operation. During the exit process, the rear-pass cam drives the rear-pass ejector mechanism to move together with the blank and the slide table, so that the operation is smooth and harmonious. Attached Figure Description

[0014] Figure 1 Rear-through cam drive route and structure diagram;

[0015] Figure 2 Schematic diagram of the transmission route and structural composition of the rear-exit cam;

[0016] Figure 3 Schematic diagram of the transmission route and structural composition of the rear through-hole cam;

[0017] Figure 4 Schematic diagram of the crank-slider mechanism;

[0018] Figure 5 A schematic diagram of the motion law curve of the slider in a crank-slider mechanism;

[0019] Figure 6 Schematic diagram of the push stroke law curve of the rear-through cam;

[0020] Figure 7 Schematic diagram of the rear ejector cam structure;

[0021] Figure 8 Back-through cam push stroke curve;

[0022] Figure 9 Schematic diagram of the rear through-cut cam structure.

[0023] The components include: 1. Bevel gear; 2. Rear drive shaft; 3. Rear ejector cam; 4. Rocker arm; 5. Rear cam; 6. Rear trimming cam; 7. Rocker arm shaft; 8. Rocker arm bushing; 9. Rocker arm roller; 10. Roller shaft; 11. Rocker arm push rod pin; 12. Safety pin; 13. Safety block; 14. Rocker arm push rod; 15. Rocker arm reset contact block; 16. Rocker arm reset spring seat; 17. Rocker arm reset push rod; 18. Rocker arm reset spring; 19. Long push rod; 20. Screw sleeve seat; 21. Threaded sleeve; 22. Transition push rod; 23. Push rod sleeve; 24. Base plate; 25. Sliding ring; 26. Front push rod; 27. Fixed mold body; 28. Mold; 29. ​​Rear base; 30. Rocker arm reset structure. Detailed Implementation

[0024] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0025] Example 1.

[0026] like Figure 1 , Figure 2 , Figure 3 As shown, the cam-type forming machine rear-through structure provided in this embodiment includes a rear-through base 29 and a rear-through ejector mechanism. A rear-through drive shaft 2, a rocker arm shaft 7, and a rocker arm reset mechanism 30 are fixedly installed on the rear-through base 29. A rear-through cam 5 is installed on the rear-through drive shaft 2, and a rear-through rocker arm 4 is installed on the rocker arm shaft 7. The rear-through drive shaft 2 drives the rear-through cam 5 to drive the rear-through rocker arm 4 to push the rear-through ejector mechanism along the cam curve trajectory of the rear-through cam 5. The rocker arm reset mechanism 30 includes a rocker arm reset ejector rod 17 and a rocker arm reset compression spring 18 that pushes the rocker arm reset ejector rod 17. Under the action of the rocker arm reset compression spring 18, the rocker arm reset ejector rod 17 makes the rear-through rocker arm 4 closely adhere to the rear-through cam 5 and resets the rear-through ejector mechanism.

[0027] The rear through-hole push rod mechanism includes a rocker arm push rod 14 mounted on the rear through rocker arm 4, a long push rod 19 fixed to the rear through base 29, a transition push rod 22, and a front push rod 26.

[0028] The rocker arm reset mechanism 30 also includes a rocker arm reset spring seat 16 for positioning the rocker arm reset top rod 17.

[0029] The rear through cam 5 includes a rear through ejector cam 3 and a rear through cutting cam 6.

[0030] To reduce wear on the contact surfaces of the rear rocker arm 4 and the rocker arm push rod 14, a rocker arm reset contact block 15 is provided on the rear rocker arm 4 and the rocker arm push rod 14.

[0031] The cam-type forming machine rear-pass structure provided in this embodiment, during operation, is driven by the main transmission from the forming machine crankshaft via bevel gear 1 to drive the rear-pass transmission shaft 2. The rear-pass transmission shaft 2 drives the rear-pass ejection cam 3 and the rear-pass trimming cam 6 to rotate. The rear-pass ejection cam 3 and the rear-pass trimming cam 6 are designed to move with the forming machine slider and meet the operational requirements; that is, the rear-pass cam ejection law of this utility model is selected and designed according to the requirements of the movement and clamping of the blank during rear-pass ejection to improve the quality of rear-pass ejection. During operation, the rear-pass cam 5 drives the rocker arm 4 to reciprocate, driving the rear ejector rod 14, long ejector rod 19, transition ejector rod 22 and front ejector rod 26 required for rear-pass ejection to move in advance, ejecting the blank or finished product in the fixed mold, realizing the rear-pass ejection function and the trimming function of the final station.

[0032] The cam-type forming machine rear-pass structure provided in this embodiment uses a rear-pass ejection mechanism with two main types of rear-pass cams 5. One type is a rear-pass ejection cam 3 for ejecting the blank. The function of the rear-pass ejection cam 3 is: after the mutual force between the moving mold and the blank is eliminated, the blank formed in the fixed mold is ejected from the fixed mold to the outside of the parting surface by the action of the ejection cam 3. The clamping mechanism then clamps and transfers it to the next station for upsetting. The cams in the first few stations of the multi-station forming machine are all of this type. The other type is a rear-pass trimming cam 6 used in the last station of the forming machine to remove the flash formed by upsetting.

[0033] The purpose of the ejector cam is to eject the workpiece from the fixed die. During the forging process, the workpiece is compressed, creating an expansion force between it and the cavity of the fixed die. There may also be a clamping force between the workpiece and the moving die on the punch. The expansion force of the workpiece within the fixed die is usually greater than the clamping force of the workpiece on the moving die. Ideally, the ejector cam should move in a way that prevents the moving die from carrying the workpiece, allowing the punch to move freely backward after detaching from the workpiece's grip. Furthermore, the workpiece should be ejected following the movement of the slide block, preventing collisions between the ejector rod and the workpiece, and also preventing collisions between the workpiece and the moving die. This creates a harmonious movement between the slide block, the workpiece, and the ejector rod. Therefore, the rear-through cam curve employs a method where the slider moves briefly to disengage the moving die from the forged blank. Subsequently, the cam pushes the ejector pin to push the blank out of the fixed die. The ejection motion follows the same pattern as the slider's movement. Thus, using the slider's backward motion as the push-stroke curve of the rear-through cam achieves a smooth, impact-free, and backlash-free ejection. Continuing the motion, the slider's speed rapidly increases, and the blank is smoothly ejected from the fixed die and clamped. At this point, the clamping is effective, and the cam can determine the motion pattern for the latter half based on the blank's ejection length requirement until the entire blank is ejected, achieving rear-through ejection.

[0034] The rear-through trimming cam is used for the final shaping of upsetting parts, removing burrs and flash generated on the head surface during the upsetting process. After the slider moves to the front dead center and completes the full forming of the product head at this station, burrs and flash will be generated on its parting surface. The trimming operation of the formed product is carried out by pushing the blank towards the moving die through the ejector pin, continuing to enter the trimming cavity to quickly remove the burrs and flash on the parting surface.

[0035] The requirements for trimming time, speed, and stroke of the back-through trimming cam are very strict. The trimming must begin when the complete head upsetting process is completed, meaning the slide must reach the front dead center. If it starts too early, the moving die is still forming the head of the workpiece, the ejector pin of the trimming mechanism will be under great force, the cut layer will be thick, and the forming quality of the head and the trimming quality will be affected, which may even damage the ejector pin and the die; if it starts too late, it must quickly catch up with and exceed the backward movement of the slide, increasing the speed and stroke of the cam. That is, when the slide reaches the front dead center, the trimming cam should immediately push the workpiece in the opposite direction towards the moving die, pushing the head of the workpiece into the inner cavity of the moving die (trimming die) to remove the burrs and flash from the head surface. Therefore, the trimming cam begins preparation before the slider reaches the front dead center (the 0º mark on the crankshaft on the cam), rapidly increasing its speed from 0 to the required trimming speed. When the slider reaches the front dead center (when its speed is 0), it quickly drives the ejector pin in the reverse direction, forcing the formed blank to move towards the moving mold. Utilizing the inner cavity of the moving mold, burrs and flash on the parting surface are quickly removed, achieving a back-through trimming. During the back-through trimming process, the cam is required to have a short stroke and high speed, with the trimming stroke exceeding the slider's stroke. It then follows the slider's movement and finally undergoes free deceleration to complete the required ejection stroke.

[0036] The cam-type forming machine rear-through structure provided in this embodiment requires that, as the slide table retracts, the forged blank moves together with the slide table, so that the front end of the blank contacts the moving die, and the rear end is pushed by the rear-through ejector mechanism. There is no impact from the rear-through ejector mechanism on the blank or the blank on the moving die, so the movement is smooth and the blank is ejected in a good state, which facilitates the correct and efficient clamping and transfer of the blank by the clamp.

[0037] The motion law of the slide table is related to the selected structure and parameters of the forming machine. For machines based on the crank-slider working principle, such as... Figure 4 As shown, the equation of motion for the slider of the forming machine is expressed in the following form:

[0038]

[0039] in

[0040] but

[0041] Simplify and rewrite as (1)

[0042] When α rotates from 0° to 180°, it is the reverse stroke, and when it rotates from 180° to 360° (back to 0°), it is the forward stroke, which is used for upsetting. The stroke of the crankshaft slider mechanism is:

[0043]

[0044] In the formula, s represents the slider stroke, which is the distance from the front dead center.

[0045] s0—Crankshaft slider mechanism stroke;

[0046] α—crankshaft rotation angle, starting from the front dead center, counterclockwise is positive and clockwise is negative;

[0047] β—The angle between the direction of motion of the connecting rod and the slider;

[0048] R—crankshaft radius;

[0049] L—Link length;

[0050] λ — Linkage coefficient.

[0051] Pick The motion law of the slide table at that time is as follows Figure 5 As shown.

[0052] Differentiating equation (1), we can obtain the velocity and acceleration of the slider as follows:

[0053] (2)

[0054] (3)

[0055] According to the requirements for the back-through cam to push the forming blank, the front section of the back-through cam follows the same motion law as the slider, which is described by formulas (1), (2) and (3) respectively. The second half of the stroke is selected according to a suitable law, such as using a constant speed motion law, to push the forming blank to the parting surface and transmit it by clamping. Then the entire cam's push stroke relationship consists of two parts, and its stroke, speed and acceleration relationship is expressed by the following formula.

[0056] journey:

[0057] (4)

[0058] speed:

[0059] (5)

[0060] (6)

[0061] The displacement, velocity, and acceleration relationships formed by the above formulas are as follows: Figure 6 As shown, in the section using the sliding table motion law, its maximum displacement is the total stroke of the rear push-out section. The velocity of the subsequent constant-velocity motion section is the same as the final velocity of the previous section, i.e., we take:

[0062]

[0063] The acceleration at the transition point is abrupt, but this is a finite change and is permissible in cam designs for low-speed motion. If better cam drive characteristics are required, other motion laws can be selected to improve the dynamic performance of the cam motion. The cam profile structure is as follows: Figure 7 .

[0064] Example 2.

[0065] The cam-type forming machine rear-pass structure provided in this embodiment has the following working process at the last station: first, the head of the forming part is upset forged; then, the head is trimmed and shaped to remove burrs and flash; then, the upset forging part is shaped into a finished product, which is ejected from the fixed mold and moves backward synchronously with the slide table, so that there is no collision or impact between the slider, the finished product and the ejector rod.

[0066] The technical requirements for edge trimming are as follows: during the process of the slider advancing to the front dead center, the head of the upsetting forging is formed; when the slider reaches the front dead center and is about to retreat, the cam drives the ejector rod, causing the blank in the fixed mold to retreat before the slider and quickly push the upsetting blank remaining in the fixed mold, so that its head moves further into the cavity of the moving mold. The flash and burrs generated on the parting surface during the head upsetting process are removed through the cavity of the moving mold, making it a finished product.

[0067] The trimming action requires synchronous retraction with the slide block, and the retraction speed must be faster than that of the slide table. The thickness of burrs and flash is not large, generally around 1mm. A relatively fast ejection speed is required in the very short time when the slide table begins to retract, so as to form a retraction stroke slightly greater than that of the slide block (greater than or equal to the thickness of the burrs and flash) to complete the trimming operation. Subsequently, the finished product with trimmed edges—the rear-through trimming ejector (driven by the rear-through trimming cam)—moves together with the moving mold with the slide table. After moving together to the required stroke (the finished product approaches the parting surface), the slide table speed is further increased, the rear-through trimming cam drives the ejector to decelerate, and the finished product is sent into the finished product channel for output.

[0068] The design requirements for the motion law of the rear through-cutting cam are as follows:

[0069] 1. When the slider moves to the front dead center (crankshaft rotation angle is 0º), the cam displacement is 0, but the required shearing speed and shearing force must be accumulated.

[0070] 2. After the shearing is completed (the shearing stroke is not large, generally within 1mm), the head of the finished product remains in the moving mold (edge ​​cutting mold) and moves with the slide until it is close to the workpiece and leaves the parting surface.

[0071] 3. After the forged product moves a certain distance synchronously with the slide table, before it leaves the mold and is fed into the finished product channel, the cam should decelerate until the movement speed is reduced to 0, and enter the far resting range of the cam.

[0072] Based on the motion law requirements of the cam, the trajectory curve of the cam's tangent segment motion law adopts the following design scheme:

[0073] 1. To ensure the cam push rod has the required cutting speed when the slide reaches the front dead center, the cam needs to move in advance to increase its speed. Therefore, the starting angle of the cam push stroke should be before the front dead center. º(- The angle (º) is determined by the design requirements for cutting speed, cutting force, and cutting thickness.

[0074] 2. The cam is only allowed to drive the workpiece when the slide begins to retract. That is, when the crankshaft begins to retract at an angle of 0°, the cam's angle is already 0°+. At º, the displacement of the cam relative to the push rod is 0. Subsequently, the advance slide requires a cut-in amount (assuming...) mm).

[0075] According to this design scheme, a suitable curve can be selected for the motion law of the cutting edge segment. In this embodiment, the motion law of the cutting edge segment of the through-cutting cam is selected as a sinusoidal law, and its relationship can be expressed as:

[0076]

[0077] in: It is the cam rotation angle of the tangent segment; δ is the tangent cam rotation angle, α is the crankshaft rotation angle, and h1 is the tangent stroke.

[0078] When the cam rotation angle is At this time, the mold completes the trimming operation. During this process, the cam-driven ejector rod travels before the slide block travels. mm. If the slider stroke pattern is expressed as:

[0079]

[0080] Then at the cam rotation angle is hour,

[0081]

[0082] The subsequent motion pattern of the trimming cam can be designed according to the ejection length requirements after trimming the upset part. It can either follow the slider for a period of time and then move to the required displacement, or directly transition to the motion pattern that achieves the ejection stroke. The motion pattern following the slider is:

[0083]

[0084]

[0085] After breaking away from synchronous motion, it can decelerate according to a suitable motion law. During the entire ejection stroke of h, the law represented by sinusoidal deceleration is as follows:

[0086]

[0087] After completing the trimming operation, the trimming cam can also choose a different motion pattern than the slider to complete the subsequent ejection stroke. Similarly, it can choose a sinusoidal deceleration pattern to complete the ejection stroke. Then:

[0088]

[0089] And this trip meets the following conditions:

[0090]

[0091] This is to prevent the cam from colliding with the moving mold when pushing the ejector pin to eject the workpiece.

[0092] In the formula:

[0093] —The cam rotation angle with a regular cutting edge segment;

[0094] —The cam rotation angle at the end of the motion law of the cam following the slide table;

[0095] —Cam rotation angle from ejection to the end of the stroke.

[0096] The motion of the cutting cam is appropriately adjusted at the connection point according to the specific situation to ensure that the speed and acceleration meet the continuity requirements, thereby obtaining good working characteristics.

[0097] Finally, it should be noted that the above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A cam-type forming machine rear passage structure, comprising a rear passage base (29) and a rear passage ejector mechanism, characterized in that... A rear-through drive shaft (2), a rocker arm shaft (7), and a rocker arm reset mechanism (30) are fixedly installed on the rear-through base (29). A rear-through cam (5) is installed on the rear-through drive shaft (2), and a rear-through rocker arm (4) is installed on the rocker arm shaft (7). The rear-through drive shaft (2) drives the rear-through cam (5) to drive the rear-through rocker arm (4) to push the rear-through push rod mechanism to run according to the cam curve trajectory of the rear-through cam (5). The rocker arm reset mechanism (30) includes a rocker arm reset push rod (17) and a rocker arm reset compression spring (18) that pushes the rocker arm reset push rod (17). Under the action of the rocker arm reset compression spring (18), the rocker arm reset push rod (17) makes the rear-through rocker arm (4) fit tightly against the rear-through cam (5) and resets the rear-through push rod mechanism.

2. The cam-type forming machine rear passage structure according to claim 1, characterized in that: The rear through-hole push rod mechanism includes a rocker arm push rod (14) mounted on the rear through rocker arm (4), a long push rod (19) fixed to the rear through base (29), a transition push rod (22), and a front push rod (26).

3. The cam-type forming machine rear passage structure according to claim 1 or 2, characterized in that: The rocker arm reset mechanism (30) also includes a rocker arm reset spring seat (16) for positioning the rocker arm reset push rod (17).

4. The cam-type forming machine rear passage structure according to claim 1 or 2, characterized in that: The rear-through cam (5) includes a rear-through ejector cam (3) and a rear-through tangent cam (6).

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