Rear through structure of cam type forming machine

Abstract

The invention discloses a cam type forming machine rear through structure 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. The cam structure is adopted, circular motion is achieved, the inertia is small, the transmission efficiency is high, compared with an old-fashioned connecting rod transmission rear-through structure, the transmission efficiency is greatly improved, and particularly, the rear-through cam drives the 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] The invention relates to a forming machine production technology, in particular to a cam type forming machine rear-pass structure. Background Art

[0002] In the prior art, the rear-through structure of the forming machine mostly uses a connecting rod to drive the rocker arm to realize the through-out function. However, due to the structure of the connecting rod, the adjustment time of the rear-through structure during operation is relatively limited, which makes it difficult to meet the requirements of the through-out of complex parts. In addition, the reciprocating motion transmission efficiency of the connecting rod is low and the inertia is large, which is not conducive to high-efficiency upsetting production. At the same time, the push stroke law of the rear-through cam adopts a commonly used motion curve, which causes motion lag or collision between the ejector and the blank during the rear-through operation. Summary of the invention

[0003] The purpose of the present invention is to solve the deficiencies of the above-mentioned technology and to provide a cam type forming machine rear-pass structure with small inertia, high transmission efficiency and suitable for the passage of complex parts.

[0004] In order to achieve the above-mentioned purpose, the present invention provides a rear-pass structure of a cam-type forming machine, which includes a rear-pass base and a rear-pass ejector mechanism, a rear-pass transmission shaft, a rocker shaft and a rocker reset mechanism are fixedly arranged on the rear-pass base, a rear-pass cam is arranged on the rear-pass transmission shaft, and a rear-pass rocker arm is arranged on the rocker shaft. The rear-pass transmission shaft drives the rear-pass cam to drive the rear-pass rocker arm to push the rear-pass ejector mechanism to operate according to the cam curve trajectory of the rear-pass cam, and the rocker reset mechanism includes a rocker reset ejector and a rocker reset compression spring that pushes the rocker reset ejector. Under the action of the rocker reset compression spring, the rocker reset ejector makes the rear-pass rocker arm close to the rear-pass cam and resets the rear-pass ejector mechanism.

[0005] The rear through-out ejector rod mechanism comprises a rocker arm ejector rod arranged on the rear through rocker arm, a long ejector rod positioned and fixed to the rear through base, a transition ejector rod and a front ejector rod.

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

[0007] The rear cam includes a rear ejection cam and a rear trimming cam. The motion law of the trimming section of the rear trimming cam is a sinusoidal law, and the relationship can be expressed as:

[0008]

[0009] Where: 01 is the cam angle of the trimming section; δ is the trimming cam angle, α is the crankshaft angle, and h1 is the trimming stroke.

[0010] In order to reduce the wear of the contact surface between the rear through rocker arm and the rocker arm top rod, a rocker arm reset contact block is provided on the rear through rocker arm and the rocker arm top rod.

[0011] The cam-type forming machine back-pass structure provided by the present invention, when working, the power driving the back-pass cam is driven by the main drive from the forming machine crankshaft through the bevel gear to drive the back-pass transmission shaft, and the back-pass transmission shaft drives the back-pass ejection cam and the back-pass trimming cam to rotate, and the back-pass ejection cam and the back-pass trimming cam are designed to move with the slider of the forming machine and meet the operation requirements; that is, the back-pass cam ejection rule of the present invention is selected and designed according to the movement and clamping requirements of the blank for the back-pass ejection, so as to improve the back-pass ejection quality. When working, the back-pass cam drives the rocker arm to swing back and forth, driving the rear ejector rod, long ejector rod, transition ejector rod and front ejector rod required by the back-pass ejection to move in advance, ejecting the blank or finished product in the fixed mold, realizing the back-pass ejection function and the trimming function of the last station.

[0012] The present invention adopts a cam structure to realize the functions of rear-pass ejection and rear-pass trimming. The time of the rear-pass action is adjusted during one working cycle to meet the rear-pass requirements of complex parts. Since the cam transmission belongs to circular motion, the inertia is small and the transmission efficiency is high. Compared with the old-fashioned connecting rod transmission rear-pass structure, the transmission efficiency is greatly improved, thereby improving the working efficiency of the whole machine.

[0013] The cam-type forming machine rear-pass structure provided by the present invention has a push stroke profile of the rear-pass cam designed according to the motion characteristics of the slide table to avoid collision between the rear-pass ejector rod mechanism and the blank during operation. During the exit process, the rear-pass cam drives the rear-pass ejector rod mechanism to move together with the blank and the slide table, and the operation is smooth and harmonious. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 Rear cam transmission route and structure diagram;

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

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

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

[0018] Figure 5 Schematic diagram of the motion law curve of the slider of the crank slider mechanism;

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

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

[0021] Figure 8 The push stroke curve of the rear-pass trimming cam;

[0022] Fig. 9 Schematic diagram of the rear-pass trimming cam structure.

[0023] Wherein: bevel gear 1, rear-through transmission shaft 2, rear-through ejector cam 3, rocker arm 4, rear-through cam 5, rear-through trimming cam 6, rocker arm shaft 7, rocker arm bushing 8, rocker arm roller 9, roller shaft 10, rocker arm ejector pin 11, safety pin 12, safety block 13, rocker arm ejector 14, rocker arm reset contact block 15, rocker arm reset spring seat 16, rocker arm reset ejector 17, rocker arm reset spring 18, long ejector 19, screw sleeve seat 20, threaded sleeve 21, transition ejector 22, ejector sleeve 23, bottom plate 24, sliding ring 25, front ejector 26, fixed mold body 27, mold 28, rear-through base 29, rocker arm reset structure 30. DETAILED DESCRIPTION

[0024] The preferred embodiments of the present invention are described below 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.

[0025] Example 1.

[0026] like Figure 1 , Figure 2 , Figure 3 As shown, the rear-pass structure of the cam-type forming machine provided in this embodiment includes a rear-pass base 29 and a rear-pass ejector mechanism, on which a rear-pass transmission shaft 2, a rocker shaft 7 and a rocker reset mechanism 30 are fixedly arranged, a rear-pass cam 5 is arranged on the rear-pass transmission shaft 2, and a rear-pass rocker arm 4 is arranged on the rocker shaft 7, the rear-pass transmission shaft 2 drives the rear-pass cam 5 to drive the rear-pass rocker arm 4 to push the rear-pass ejector mechanism to operate according to the cam curve trajectory of the rear-pass cam 5, the rocker reset mechanism 30 includes a rocker reset ejector 17 and a rocker reset compression spring 18 that pushes the rocker reset ejector 17, and under the action of the rocker reset compression spring 18, the rocker reset ejector 17 makes the rear-pass rocker arm 4 close to the rear-pass cam 5 and resets the rear-pass ejector mechanism.

[0027] The rear through-out push rod mechanism includes a rocker arm push rod 14 arranged on the rear through rocker arm 4 , a long push rod 19 positioned and 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 further includes a rocker arm reset compression spring seat 16 for positioning the rocker arm reset push rod 17 .

[0029] The rear cam 5 includes a rear ejection cam 3 and a rear trimming cam 6.

[0030] In order to reduce the wear of the contact surface between the rear through rocker arm 4 and the rocker arm top rod 14 , a rocker arm reset contact block 15 is provided on the rear through rocker arm 4 and the rocker arm top rod 14 .

[0031] The cam-type forming machine back-pass structure provided in this embodiment, when working, the power driving the back-pass cam 5 is driven by the main transmission from the forming machine crankshaft through the bevel gear 1 to drive the back-pass transmission shaft 2, and the back-pass transmission shaft 2 drives the back-pass ejection cam 3 and the back-pass trimming cam 6 to rotate, and the back-pass ejection cam 3 and the back-pass trimming cam 6 are designed to move with the slider of the forming machine and meet the operation requirements; that is, the back-pass cam ejection rule of the present invention is selected and designed according to the movement and clamping requirements of the blank for the back-pass ejection, so as to improve the back-pass ejection quality. When working, the back-pass cam 5 drives the rocker arm 4 to swing back and forth, driving the back ejector rod 14, the long ejector rod 19, the transition ejector rod 22 and the front ejector rod 26 required by the back-pass ejection to move in advance, ejecting the blank or finished product in the fixed mold, and realizing the back-pass ejection function and the trimming function of the last station.

[0032] The cam-type forming machine provided in this embodiment has a rear-through structure, and the rear-through ejection mechanism adopts two main types of rear-through cams 5. One is the rear-through ejection cam 3 for ejecting the blank. The function of the rear-through ejection cam 3 is: after the mutual force between the movable mold and the blank is eliminated, the blank upset in the fixed mold is ejected from the fixed mold to the outside of the parting surface through the action of the ejection cam 3, and is clamped by the clamp mechanism and transferred to the next station for upsetting. The cams of the first few stations of the multi-station forming machine are of this type; the other is the rear-through trimming cam 6 used in the last station of the forming machine to cut off the flash formed by upsetting.

[0033] The purpose of the rear ejector cam is to eject the blank in the fixed die. During the upsetting process, the blank is compressed, and there is an expansion force between the blank and the inner cavity of the fixed die. There may be a tightening force between the blank and the movable die. The expansion force of the blank in the fixed die is usually greater than the tightening force of the blank on the movable die. The ideal movement law of the ejector cam is that the movable die cannot move with the blank, and the movable die punch can move backward freely after being separated from the clamp of the blank, and the blank is ejected closely following the movement of the slider, without causing the ejector rod to collide with the blank, nor should the blank collide with the movable die, forming a harmonious law of slider-blank-ejector follow-up. Therefore, the back-through cam curve uses the method of letting the slider move for a while to separate the movable die on the slider from the upset blank, and then the cam pushes the ejector to eject the blank remaining in the fixed die. The ejection motion law is the same as the motion law of the slider. Therefore, the backward motion law of the slider is used as the push stroke curve of the back-through cam, which can achieve a smooth and impact-free, follow-up and gap-free ejection law. Continuing to move, the speed of the slider increases rapidly, and the blank is smoothly pushed out of the fixed die and clamped by the clamp. At this time, the clamping state is good, and the cam can determine the motion law of the second half according to the ejection length requirements of the blank until the entire blank is pushed out to achieve back-through ejection.

[0034] The rear trimming cam is the last step of shaping the upset parts, and it removes the flash and burrs generated on the head surface during the upset process. After the slider moves to the front dead point to complete the complete 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 to push the blank toward the moving mold through the ejector rod, and continue to enter the trimming cavity to quickly remove the burrs and flash on the parting surface.

[0035] The requirements for the trimming time, speed and stroke of the rear-pass trimming cam are very strict. The trimming must start when the head is completely upset, that is, the slider must reach the front dead center. If it is too early, the movable mold is still forming the head of the blank, the ejector of the trimming mechanism is under great force, the cutting layer is thick, and the forming quality and trimming quality of the head are affected, and even the ejector and the mold are damaged; if it is too late, it must quickly catch up and exceed the backward movement of the slider, and increase the speed and stroke of the cam. That is, when the slider moves forward and reaches the front dead center, the trimming cam should immediately push the blank in the opposite direction toward the movable mold, and push the blank head into the inner cavity of the movable mold (trimming mold) to cut off the burrs and flash on the surface of the head. Therefore, the trimming cam starts to prepare before the slider reaches the front dead center (the crankshaft 0° mark on the cam), and quickly increases its speed from 0 to the speed required for trimming. When the slider reaches the front dead center (the slider speed is 0), the ejector rod is quickly driven in the backward direction to force the formed blank to move toward the movable mold. The burrs and flash on the parting surface are quickly removed using the inner cavity of the movable mold to achieve back-pass trimming. In the back-pass trimming process, the requirements for the cam are short stroke and fast speed, and the trimming stroke must be greater than the movement stroke of the slider; followed by the movement of the slider, and finally the free deceleration movement to complete the required ejection stroke.

[0036] The cam-type forming machine rear-through structure provided in this embodiment requires that the aforementioned rear-through ejection requires that when the slide retreats, the upsetting blank moves with the slide, so that the front end of the blank contacts the movable die, and the rear end is pushed by the rear-through ejector mechanism. There is no impact of the rear-through ejector mechanism on the blank or the blank on the movable die, the movement is smooth, the ejection state of the blank is good, and the correct and efficient clamping and transfer of the blank by the clamps is convenient.

[0037] The motion law of the slide is related to the structural form and parameters of the selected forming machine. Figure 4 As shown, the slider motion equation of the forming machine is expressed in the following form:

[0038] s=(R+L)-(Rcosα+Lsinβ)

[0039] in

[0040] but

[0041] Simplified and rewritten as

[0042] When α turns from 0° to 180°, it is a backward stroke, and when it turns from 180° to 360° (back to 0°), it is a forward stroke, and the upsetting operation is performed. The stroke of the crankshaft slider mechanism is:

[0043] s0=2R

[0044] Where s is the slider stroke, from the front dead center position;

[0045] s0—crankshaft slider mechanism stroke;

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

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

[0048] R—crankshaft radius;

[0049] L—connecting rod length;

[0050] λ—Connecting rod coefficient.

[0051] When R = 100 mm and λ = 0.25, the motion law of the slide is as follows: Figure 5 shown.

[0052] By taking the derivative of equation (1), we can get the velocity and acceleration of the slider as follows:

[0053]

[0054] a=-ω 2 R(cosα+λcos2α) (3)

[0055] According to the requirements for the rear cam to push the formed blank, the front section of the rear cam is the same as the motion law of the slider, which is described by formulas (1), (2) and (3) respectively. The second half of the stroke is selected with a suitable law, such as the uniform velocity motion law, to push the formed blank to the parting surface and transfer it by clamping it. Then the pushing stroke relationship of the entire cam is composed of two parts, and the relationship between its stroke, speed and acceleration is expressed by the following relationship.

[0056] journey:

[0057]

[0058]

[0059]

[0060] The relationship between displacement, velocity and acceleration formed by the above relationship is as follows: Figure 6As shown, the maximum displacement of the sliding table in the front section is the total stroke of the rear ejection, and the speed of the equal-speed motion part in the rear section is consistent with the end speed of the front section, that is, take:

[0061]

[0062] The acceleration at the transition point changes suddenly, which is a limited change. The cam design under low-speed motion is allowed. If better cam driving 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 .

[0063] Example 2.

[0064] The cam-type forming machine rear-pass structure provided in this embodiment has a working process of the last station of the forming machine that first performs upsetting forging on the head of the formed part, then trims and shapes the head to remove burrs and flash; then the upsetting forged part is made into a finished product after shaping, ejected from the fixed mold, and retreats synchronously with the retreat of the slide, so that no collision or impact occurs between the slide, the finished product, and the ejector rod.

[0065] The technical requirement for trimming is that the head of the upsetting forging is formed in the process of the slider moving forward to the front dead point; when the slider reaches the front dead point and is ready to retreat, the cam drives the push rod to make the blank in the fixed die retreat before the slider, and quickly hit the upsetting blank remaining in the fixed die, so that its head moves further into the cavity of the movable die, and the flash and burrs generated on the parting surface during the head upsetting process are removed through the cavity of the movable die to make it a finished product.

[0066] The trimming action requires synchronous retreat with the slider, and the retreat speed must be faster than the slide; the thickness of burrs and flash is not large, generally around 1 mm, and a faster ejection speed is required in a very short time when the slide starts to retreat, so as to form a retreat stroke slightly larger than the slider (greater than or equal to the thickness of burrs and flashes) to complete the trimming operation; then the finished product after trimming and shaping - the rear-pass trimming ejector rod (driven by the rear-pass trimming cam) - the movable mold moves with the slide; after moving together to the required stroke (the finished product approaches to leaving the parting surface), the slide speed is further accelerated, the rear-pass trimming cam drives the ejector rod to decelerate, and the finished product is sent to the finished product channel for output.

[0067] The design requirements for the motion law of the rear-pass cutting edge cam are as follows:

[0068] 1. When the slider moves to the front dead center (the crankshaft angle is 0°), the displacement of the cam is 0, but the required shear speed and shear force must be accumulated;

[0069] 2. After the shearing is completed (the shearing stroke is not large, generally within 1 mm), the head of the finished product remains in the movable mold (trimming mold) and moves with the slide until it approaches the workpiece and leaves the fractal surface.

[0070] 3. After the upsetting product moves synchronously with the slide for a certain distance, before leaving the die and being sent into the finished product channel, the cam should slow down until the movement speed drops to 0 and enter the far rest range of the cam.

[0071] According to the motion law requirements of the trimming cam, the trajectory curve of the motion law of the trimming section of the cam adopts the following design scheme:

[0072] 1. In order to ensure that 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 the speed. Therefore, the starting angle of the cam push stroke should be α° (-α°) before the front dead center. The angle is determined by the designed cutting speed, cutting force, cutting thickness and other requirements.

[0073] 2. The cam is allowed to drive the blank only when the slide starts to retreat. That is, when the crankshaft starts to retreat at a crankshaft angle of 0° and the cam angle is 0°+α°, the displacement of the cam on the push rod is 0. Subsequently, the advance slide movement requires the required cutting-in amount (assuming h0mm).

[0074] According to this design, the motion law of the trimming section can select a suitable curve. In this embodiment, the motion law of the trimming section of the rear trimming cam selects the sine law, and the relationship can be expressed as:

[0075]

[0076] Where: 01 is the cam angle of the trimming section; δ is the trimming cam angle, α is the crankshaft angle, and h1 is the trimming stroke.

[0077] When the cam angle is δ 01 When the mold completes the trimming operation, the cam-driven ejector stroke precedes the slider stroke h0mm. If the slider stroke rule is expressed as:

[0078]

[0079] Then when the cam rotation angle is δ 01 hour,

[0080] f1(δ 01 )=f0(δ 01 )+h0=h1+h0

[0081] The movement law of the trimming cam can be designed according to the ejection length requirements of the trimming parts. You can choose to follow the slider for a period of time, and then run to the required displacement as required; you can also directly transition to the law of realizing the ejection stroke. The law of movement with the slider is:

[0082] f2(δ)=f0(δ)+h0(δ 01 ≤δ≤δ 02 )

[0083] f2(δ2)=f0(δ2)+h0=h2+h0(δ 01 ≤δ≤δ 02 )

[0084] After the synchronous motion is separated, the deceleration motion can be carried out according to the appropriate motion law. When the entire ejection stroke is h, the law expressed by the sinusoidal deceleration motion is:

[0085]

[0086] After completing the trimming operation, the trimming cam can also choose a different law from the slider movement to complete the subsequent ejection stroke. It can also choose a sinusoidal deceleration law to move until the ejection stroke is completed, then:

[0087]

[0088] And this trip meets the following conditions:

[0089] f4(δ)-f3(δ)≤h0(δ 01 ≤δ≤δ0)

[0090] This is to prevent the cam from pushing the ejector pin to eject the workpiece and colliding with the movable mold.

[0091] Where:

[0092] δ 01 - Regular cam rotation angle of the trimming section;

[0093] δ 02 ——The cam rotation angle when the cam ends the motion law of the slide;

[0094] δ0——Cam rotation angle from ejection to the end of stroke.

[0095] The trimming cam motion is appropriately adjusted at the connection point according to the specific situation so that the speed and acceleration meet the continuity requirements and good working characteristics can be obtained.

[0096] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A cam type forming machine rear-pass structure, which comprises a rear-pass base (29) and a rear-pass ejector mechanism, characterized in that A rear-through transmission shaft (2), a rocker arm shaft (7) and a rocker arm reset mechanism (30) are fixedly arranged on a rear-through base (29); a rear-through cam (5) is arranged on the rear-through transmission shaft (2); and a rear-through rocker arm (4) is arranged on the rocker arm shaft (7); the rear-through transmission shaft (2) drives the rear-through cam (5) to drive the rear-through rocker arm (4) to push the rear-through ejector mechanism to operate according to the cam curve track of the rear-through cam (5); the rocker arm reset mechanism (30) comprises a rocker arm reset ejector rod (17) and a rocker arm reset compression spring (18) for pushing 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) close to the rear-through cam (5) and resets the rear-through ejector mechanism.

2. The rear-pass structure of the cam-type forming machine according to claim 1 is characterized in that The rear through-out push rod mechanism comprises a rocker arm push rod (14) arranged on a rear through rocker arm (4), a long push rod (19) positioned and fixed to a rear through base (29), a transition push rod (22) and a front push rod (26).

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

4. The rear-pass structure of the cam-type forming machine according to claim 1 or 2, characterized in that The rear-through cam (5) comprises a rear-through ejection cam (3) and a rear-through trimming cam (6).

5. The rear-pass structure of the cam-type forming machine according to claim 4 is characterized in that The motion law of the trimming section of the rear trimming cam (6) is a sinusoidal law, and the relationship can be expressed as: Where: 01 is the cam angle of the trimming section; δ is the trimming cam angle, α is the crankshaft angle, and h1 is the trimming stroke.

Images