Cam type forming machine shearing structure

Abstract

The present invention discloses a cam type forming machine shearing structure, comprising a shearing mechanism and a transmission mechanism, and is characterized in that the transmission mechanism controls the travel trajectory of a scissor rod in the shearing mechanism through a shearing cam, the pushing stroke of the shearing cam is composed of a shearing stroke and a shearing material feeding stroke, and a shearing cam curve that determines the shearing stroke is a curve for realizing acceleration characteristics or a combination of a curve for realizing acceleration characteristics and a uniform speed characteristic curve; the cam type forming machine shearing structure provided by the present invention can enable the push rod to obtain various expected motion laws through a special cam curve of the shearing cam profile, and has a fast response, a simple and compact structure, and can accelerate the shearing speed, so that a smoother material fracture can be obtained when shearing the material, thereby improving the quality of the upsetting product; compared with the traditional shearing structure, the structural design is greatly simplified, the machine space size is optimized, the number of parts is reduced, and the part design is simpler and convenient to process.

Description

Technical Field

[0001] The invention relates to a forming machine production technology, in particular to a cam type forming machine shearing structure. Background Art

[0002] In the production of forming machines in the prior art, the shearing structure usually adopts an eccentric connecting rod mode. This shearing method has a complex structure, occupies a large space, has a large number of parts, and is particularly slow in shearing speed, which results in uneven cuts on the cut material. 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 shearing structure with a smooth cut of the material after shearing and a simple shearing structure.

[0004] In order to achieve the above-mentioned purpose, the present invention provides a cam-type forming machine shearing structure, including a shearing mechanism and a transmission mechanism, wherein the transmission mechanism controls the travel trajectory of the scissor rod in the shearing mechanism through a shearing cam, and the pushing stroke of the shearing cam is composed of a shearing stroke and a shearing material feeding stroke. The shearing cam curve that determines the shearing stroke is a curve that realizes acceleration characteristics or a combination of a curve that realizes acceleration characteristics and a uniform speed characteristic curve; the curve that realizes acceleration characteristics is such as the equal acceleration law, the sine law, the cosine law, etc.

[0005] A rocker mechanism may also be provided between the shearing mechanism and the transmission mechanism, and the shearing cam controls the travel trajectory of the scissor lever in the shearing mechanism by controlling the swing stroke of the rocker arm in the rocker mechanism.

[0006] The rocker mechanism comprises a rocker and a rocker shaft. A first roller and a second roller are respectively arranged at both ends of the rocker. The first roller moves along the shear cam curve; the second roller pushes the scissor rod to move through the contact block in the shear mechanism.

[0007] The shearing mechanism comprises a shearing box and a shearing rod running through the shearing box, a shearing rod copper sleeve is arranged on the shearing rod, a shearing knife seat and a shearing knife are arranged at the front end of the shearing rod; a spring top plate and a contact block in contact with the rocker arm mechanism are fixedly arranged at the rear end of the shearing rod; a spring rod and a return spring for returning the shearing rod are arranged between the spring top plate and the shearing box.

[0008] The transmission mechanism comprises a transmission shaft for driving the shearing cam to rotate, a transmission bevel gear and a transmission gear for driving the transmission shaft to rotate, and the transmission gear is provided with transmission power through the crankshaft.

[0009] The motion law of the shear stroke section of the acceleration characteristic curve in the shear cam curve satisfies the following function law:

[0010] The motion law of the shear stroke section of the shear mechanism push curve can be expressed as:

[0011]

[0012] The movement of the feeding section of the shear mechanism push curve is still expressed by the sine law and can be expressed as:

[0013]

[0014] The velocity and acceleration of the shear segment are:

[0015]

[0016]

[0017] The speed and acceleration of the feeding section are:

[0018]

[0019] The combination of the acceleration characteristic curve and the average speed characteristic curve in the shear cam curve satisfies the following function law:

[0020] The displacement function of the combination rule:

[0021]

[0022] The speed function of the combination law:

[0023]

[0024] The acceleration function of the combination law:

[0025]

[0026] The cam forming machine shearing structure provided by the present invention is transmitted from the crankshaft to the transmission shaft through the transmission gear and the transmission bevel gear during operation, and the shearing mechanism is driven by the shearing cam on the transmission mechanism. According to the arrangement and conditions of the transmission mechanism, when the transmission shaft is located near the shearing mechanism and the offset is very small, the shearing mechanism can be directly driven by the cam, eliminating the rocker mechanism, and reducing the torque acting on the cam while making the cam under less force; when the distance is large, the shearing cam transmits the movement of the shearing cam to the shearing mechanism through the rocker in the rocker mechanism. In practical applications, the middle rocker mechanism is often used, and the relationship between the lengths of different active arms and driven arms is selected in the rocker mechanism, so as to change the outline size and force of the shearing cam, and facilitate the overall arrangement and design of the shearing cam.

[0027] The cam forming machine shearing structure provided by the present invention has the following functions: the push rod can obtain various expected motion laws through the special cam curve of the shearing cam profile, and the response is fast. The structure is simple and compact, and the shearing speed can be accelerated, so that a smoother material fracture can be obtained when the material is sheared, thereby improving the quality of the upset forging product; compared with the traditional shearing structure in structure, the eccentric connecting rod model is no longer used, the structural design is greatly simplified, the machine space size is optimized, the number of parts is reduced, and the part design is simpler, the processing is convenient, and the machine performance is more optimized.

[0028] The present invention provides a cam type forming machine shearing structure, especially a combined design of the motion law of the cam push curve that drives the shearing mechanism to shear the upset wire, which improves the shear surface quality of the forming machine on the wire and effectively improves the quality of the upset product. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the position structure of the shear cam in the transmission system;

[0030] Figure 2 It is a schematic diagram of the transmission relationship between the shearing cam and the shearing mechanism;

[0031] Figure 3 It is the phase relationship and basic curve diagram of the shear cam;

[0032] Figure 4 It is a derivation curve diagram of the combined sinusoidal acceleration motion law;

[0033] Figure 5 It is a deduction curve diagram that combines sinusoidal acceleration and the law of constant velocity motion.

[0034] Among them: crankshaft 11, transmission gear 12, transmission bevel gear 13, transmission shaft 14, shearing mechanism 17, shearing cam

[0035] 21, first roller 22, rocker arm 23, rocker arm shaft 24, second roller 25, scissor rod 26, shear box 27, shear rod copper sleeve 28, shear knife seat 29, shear knife 291, spring top plate 30, contact block 31, spring rod 32, return spring 33. DETAILED DESCRIPTION

[0036] 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.

[0037] Example 1.

[0038] like Figure 1 , Figure 2As shown, the present embodiment describes a cam type forming machine shearing structure, comprising a shearing mechanism 17 and a transmission mechanism, wherein the transmission mechanism controls the travel trajectory of the scissor rod 26 in the shearing mechanism through a shearing cam 21, the pushing stroke h of the shearing cam 21 is composed of a shearing stroke h1 and a shearing material feeding stroke h2, and the shearing cam curve that determines the shearing stroke h1 is a curve for realizing acceleration characteristics or a combination of a curve for realizing acceleration characteristics and a uniform speed characteristic curve; the curve for realizing acceleration characteristics may be, for example, an equal acceleration law, a sine law, a cosine law, and the like.

[0039] A rocker mechanism may also be provided between the shearing mechanism and the transmission mechanism, and the shearing cam 21 controls the stroke trajectory of the scissor lever 26 in the shearing mechanism by controlling the swing stroke of the rocker arm 23 in the rocker mechanism.

[0040] The rocker mechanism includes a rocker 23 and a rocker shaft 24. A first roller 22 and a second roller 25 are respectively arranged at both ends of the rocker. The first roller 22 moves along the shear cam 21 curve; the second roller 25 pushes the scissor rod 26 to move through the contact block 31 in the shear mechanism.

[0041] The shear mechanism 17 includes a shear box 27 and a shear rod 26 running through the shear box 27, a shear rod copper sleeve 28 is provided on the shear rod 26, a shear knife seat 29 and a shear knife 291 are provided at the front end of the shear rod 26; a spring top plate 30 and a contact block 31 in contact with the rocker mechanism are fixedly provided at the rear end of the shear rod 26; a spring rod 32 and a return spring 33 for returning the shear rod 26 are provided between the spring top plate 30 and the shear box 27.

[0042] The transmission mechanism includes a transmission shaft 14 for driving the shear cam 21 to rotate, and a transmission bevel gear 13 and a transmission gear 12 for driving the transmission shaft 14 to rotate. The transmission gear 12 is provided with transmission power through the crankshaft 11 .

[0043] When working, the crankshaft 11 transmits the force to the transmission shaft 14 through the transmission gear 12 and the transmission bevel gear 13, and the shearing mechanism is driven by the shearing cam 21 on the transmission mechanism. According to the arrangement and conditions of the transmission mechanism, when the transmission shaft is located near the shearing mechanism and the offset is very small, the shearing mechanism can be directly driven by the cam, eliminating the rocker mechanism, and reducing the torque acting on the cam while making the cam under less force; when the distance is large, the shearing cam 21 transmits the movement of the shearing cam 21 to the shearing mechanism 17 through the rocker 23 in the rocker mechanism. In practical applications, the intermediate rocker mechanism is often used, such as Figure 2 As shown, by selecting different length relationships between the active arm 1 and the driven arm 2 in the rocker arm mechanism, the outline size and force of the shear cam 21 can be changed, which facilitates the overall layout and design of the shear cam 21.

[0044] When the forming machine is working, the crankshaft in the transmission mechanism transmits power to each executive part of the system. There is a strict phase relationship between each part to ensure the coordination of each movement, which is determined by the working cycle diagram of the forming machine. The slider mechanism is responsible for the upsetting of the blank. The upsetting blank must be cut into sections of a certain size (length or volume) from the coil before starting the upsetting, and transferred to the first station by the clamp.

[0045] If the crankshaft angle of the slider at the front dead center is 0°, the shearing mechanism must first cut the coil into blanks required for upsetting before the slider reaches the front dead center, and then the clamp will send it to the first station. When the movable die on the slider contacts the blank, it will be upset between the movable and fixed dies to form the initial first deformation, and then it will be sent to the subsequent station by the clamp for continuous deformation until it is formed; before the slider reaches the front dead center, the shearing mechanism should return to its original position.

[0046] On the other hand, from a work cycle analysis, shortly after the slider retreats, the shearing mechanism will cut the fixed-length material fed from the coil and send it to the position where the clamp takes the material (the material taking station, for the nut machine, it is often sent directly to the first station). Subsequently, the clamp takes out the blank from the shearing mechanism at the material taking station and transfers it to the upsetting station. After the blank of the shearing mechanism is taken away by the clamp, the shearing mechanism can consider retreating. There is often an operation time (phase) coordinated with the feeding of the coil from cutting to retreating. This is the working phase relationship that the shearing cam design must consider, which is determined by the overall design work cycle diagram ( Figure 3 ).

[0047] The shearing mechanism of the forming machine consists of three strokes during the shearing process. The first stroke is the approach stroke, in which the cutter of the shearing mechanism approaches but does not affect the feeding operation of the straightened coil, and is in the shearing position of the material with a set length; the second stroke is the cutting stroke, the goal is to cut the material with a diameter of d, and it is also the core content of the shearing cam's work; the third stroke is the feeding stroke, which sends the cut bad material to the clamping position (screw machines, etc. have special clamping stations, and nut machines are often sent directly to the first station).

[0048] The feeding stroke of the third stroke is often larger than the cutting stroke of the second stroke; the feeding stroke of large-size forming machines with large cutting diameters is also larger; the cutting stroke of the second stroke is theoretically the diameter of the shear line material, and for the forming machine, it is the maximum shear diameter set by the machine; the approach stroke is often relatively small. When the shear mechanism is in the original position, the position of the shear knife does not affect the feeding of the coil, and its minimum theoretical value is close to 0.

[0049] The cam type forming machine shearing structure provided by the present invention has the following functions: through the special curve of the disc cam, the design of the cam push segment law that meets the working requirements is studied, the shearing performance of the shearing mechanism is optimized, and the high-quality shear section quality is obtained. The return segment of the shearing cam does not participate in the shearing work, and the present invention does not analyze it, and the commonly used motion law curve design can be selected.

[0050] From the perspective of shearing, the shear knife has a fast speed, and when cutting the wire, a smoother fracture shape can be obtained, which prevents the generation of flash and burrs on the cut, thereby obtaining better upsetting product quality.

[0051] There are two ways to increase the shear speed: one is to increase the shear speed when entering the material for shearing. The shear knife can be moved away from the wire by a certain distance in the initial position. In this way, when the shear knife enters the shearing, it has a certain shear speed; the other is to continuously increase the speed of the shear knife during the shearing movement.

[0052] The starting speed of the cam movement is usually 0. To increase the starting speed of shearing, it is necessary to increase the distance between the shearing tool and the wire, which will increase the stroke of the shearing mechanism. To increase the shearing speed during the shearing process, it is necessary to use a cam profile curve with accelerated motion.

[0053] After shearing is completed, the sheared blank is clamped at the cutting edge of the shear knife and continues to be fed forward with the movement of the shearing mechanism. Under normal circumstances, the clamping position and clamping force position of the forming machine are basically unchanged. When the length of the sheared material is different, the position and the acceleration and deceleration movement are too large, which will cause the clamped blank to be skewed, affecting the blank posture when the subsequent clamp is clamped and fed. Therefore, when the shearing mechanism is in the feeding stroke, the required feeding speed should not be too fast, and the acceleration and deceleration should not change sharply.

[0054] The ideal shearing stroke curve of the forming machine cam has a high shearing speed during the shearing process, which can quickly shear the material and improve the quality of the shear cut; at the end of shearing, it should not still be in an accelerated state, but should be in the fastest speed state or close to the fastest speed, and preferably in a decelerated state.

[0055] In the design of cam curves, the cosine acceleration motion law and the sine acceleration motion law are used more frequently. The basic characteristics of these two curves are that the motion speed is continuous and the maximum motion speed is at the middle point of the entire push range. This means that no matter whether the sine acceleration motion law or the cosine acceleration motion law is selected, in the actual shearing process, the maximum speed is reached after the shearing is completed, and the maximum speed does not play a role in improving the quality of the shearing surface during shearing. In the process of feeding the shearing blank, there is still a continuous acceleration and then a deceleration movement, which affects the transmission quality of the blank.

[0056] There is no specific requirement for the return stroke of the shear cam. It only needs to return to the starting point of the movement within the specified time to prepare for the next shearing. The focus of the shear cam of the forming machine is to optimize the push stroke curve and improve the shearing quality of the material.

[0057] The cam curve design of the present invention selects a combined curve that meets the shearing and feeding quality requirements.

[0058] As mentioned above, the approach stroke of the shearing mechanism is usually relatively small. The shearing stroke is to cut the wire, and its size is the maximum shearing diameter set by the forming machine. The feeding stroke depends on the overall design requirements of the type of forming machine (nut machine or screw machine). No matter from which aspect, the feeding stroke will be greater than the shearing stroke. Since the approach stroke is relatively small, when designing the cam curve, two strokes are mainly considered, namely the cutting stroke and the feeding stroke. According to the operating requirements and stroke size of these two strokes, select the appropriate curve combination.

[0059] The cam's push stroke h is composed of the shear stroke h1 and the feed stroke h2:

[0060] h=h1+h2

[0061] In order to make the designed cam curve meet the special requirements of shearing, the shearing stroke is:

[0062] h1=d

[0063] The delivery process is:

[0064] h2≥d

[0065] Where d is the shear diameter required by the forming machine.

[0066] In order to obtain better shear surface quality, the speed during the shearing process should be as large as possible. Therefore, the curve selected to achieve the acceleration characteristics in the shearing stroke can meet the requirements, such as the equal acceleration law, sine law, cosine law, etc.

[0067] In this embodiment, two different sinusoidal law combinations are used. In the shearing stroke, the sinusoidal law is used, which means that the speed gradually increases during the entire shearing process, which is an acceleration process. The acceleration gradually increases at the beginning, reaches the maximum in the middle of the stroke, and then decreases in the second half, and the acceleration is 0 when the shearing is reached, and the speed reaches the maximum.

[0068] The motion law of the shear stroke section of the shear mechanism push curve can be expressed as:

[0069]

[0070] The movement of the feeding section of the shear mechanism push curve is still expressed by the sine law and can be expressed as:

[0071]

[0072] In the shear stroke section, the range of δ is 0~δ 01 , the entire journey is from 0 to h1(d).

[0073] The range of δ in the feeding process section is δ 01 ~δ0, angle δ 02 =δ0―δ 01 , the entire journey is h1(d)~h.

[0074] Taking the first and second order derivatives of the above two motion laws respectively, we can get the velocity and acceleration as follows:

[0075] The velocity and acceleration of the shear segment are:

[0076]

[0077]

[0078] The speed and acceleration of the feeding section are:

[0079]

[0080] During the entire cam stroke,

[0081] When δ=0, h=0, v=0, a=0

[0082] When δ=δ 01 hour,

[0083] At the end of the shear stroke,

[0084] At the beginning of the sending process,

[0085] When δ=δ0=δ 01 +δ 02 When h=h1+h2, v=0, a=0

[0086] According to the cam's push law, its displacement, speed, and acceleration must be continuous. Therefore, at the end of shearing, the transition point to the start is:

[0087] When δ=δ 01 When

[0088] The relationship between lift and angle must meet the following conditions:

[0089]

[0090] That is, by segmenting the lift and rotation angle according to a linear relationship, two curves operating according to different sine laws can be obtained. The relationships among displacement, velocity, and acceleration are shown in Figure 4 .

[0091] When h1 = h2, it is a typical sine law.

[0092] In this embodiment, when h1 = d, during the process of the cam shearing the wire, the speed continuously increases. First, the acceleration also increases, and then the acceleration decreases. The speed reaches the maximum at the end of shearing, and the positive acceleration decreases to 0; during the subsequent feeding stroke, the acceleration is negative, and the speed gradually decreases until the end of the pushing stroke, when both the speed and acceleration are 0.

[0093] Considering the influence of the approach stroke of the cam, when h1 = d and the cam reaches the maximum speed and the positive acceleration drops to 0, the shearing mechanism has not completely sheared the wire, leaving a margin equivalent to the approach stroke. In the part of the remaining cross-section of the wire being cut, the cam curve enters the next segment of the sine law with negative acceleration, and the stroke in this feeding segment is large and the deceleration is slow. The speed when cutting the remaining material part is close to the maximum speed, meeting the requirements that the cam design shearing speed should be as fast as possible and the feeding speed should be slow, which is still an ideal result. During the subsequent feeding stroke, the feeding speed continues to decrease until the speed reaches 0 when it is fed to the first station or the clamping position of the clamp.

[0094] Embodiment 2

[0095] For the shearing of various materials, there is an appropriate shearing speed required for each. The shearing speed in Embodiment 1 reaches its shearing speed at the end of shearing, which has a gap from the ideal shearing requirements. To reach the ideal shearing speed as soon as possible during shearing, further acceleration is required in the front section of the shearing stroke.

[0096] In this embodiment, the speed is increased rapidly in the early stage of the shearing stroke segment. When the required speed is reached, shearing is carried out at a constant speed. Similarly, the stroke of the shearing segment is set to the diameter d of the material to be cut. Then the stroke of the acceleration segment is less than the material diameter d. Let h1 be determined by the required speed, the stroke of the constant speed segment is h2, and the total stroke of the two is d. The stroke of the entire pushing stroke of the cam is h0, then there are:

[0097] h1 < d (such as taking d / 2)

[0098] h1 + h2 = d

[0099] h1 + h2 + h3 = h0

[0100] Similarly, the sine law is selected as the contour curve of the front and rear two segments of the cam pushing stroke, and the constant speed first-order polynomial motion law is used in the middle segment. The motion laws of the three segments of the contour are expressed as:

[0101] The displacement function of the combination rule:

[0102]

[0103] The speed function of the combination law:

[0104]

[0105] The acceleration function of the combination law:

[0106]

[0107] When δ=0, h=0, v=0, a=0;

[0108] When δ=δ 01 When h = h1, or a=0;

[0109] When δ=δ 02 When h = h1 + h2, or a=0;

[0110] When δ=δ0, h=h1+h2+h3, v=2h3ω, a=0;

[0111] The velocity continuity condition is:

[0112]

[0113] That is, the relationship must be satisfied:

[0114]

[0115] or

[0116]

[0117] The displacement, velocity and acceleration diagrams of the push process segment composed of these three curves are given by Figure 5 shown.

[0118] Similarly, the push motion law of the shear cam can be implemented in combination with other basic motion laws, such as the cosine law, equal acceleration and equal deceleration, etc., according to the working requirements.

[0119] 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 forming machine shearing structure, comprising a shearing mechanism and a transmission mechanism, characterized in that The transmission mechanism controls the travel trajectory of the scissor rod (26) in the shearing mechanism through a shearing cam (21); the pushing stroke of the shearing cam (21) is composed of a shearing stroke and a shearing material feeding stroke; the shearing cam curve that determines the shearing stroke is a curve that realizes acceleration characteristics or a combination of a curve that realizes acceleration characteristics and an average speed characteristic curve.

2. The cam forming machine shearing structure according to claim 1 is characterized in that A rocker mechanism is also provided between the shearing mechanism and the transmission mechanism. The shearing cam (21) controls the swing stroke of the rocker arm (23) in the rocker mechanism, thereby controlling the stroke trajectory of the scissor rod (26) in the shearing mechanism.

3. The cam forming machine shearing structure according to claim 2 is characterized in that The rocker mechanism comprises a rocker arm (23) and a rocker arm shaft (24). A first roller (22) and a second roller (25) are respectively arranged at both ends of the rocker arm (23). The first roller (22) moves along the shear cam (21) curve; the second roller (25) pushes the scissor rod (26) to move through a contact block (31) in the shear mechanism.

4. The cam forming machine shearing structure according to claim 1 or 2, characterized in that The shearing mechanism comprises a shearing box (27) and a shearing rod (26) penetrating the shearing box (27); a shearing rod copper sleeve (28) is provided on the shearing rod (26); a shearing knife seat (29) and a shearing knife (291) are provided at the front end of the shearing rod (26); a spring top plate (30) and a contact block (31) in contact with a rocker mechanism are fixedly provided at the rear end of the shearing rod (26); a spring rod (32) and a return spring (33) for returning the shearing rod (26) are provided between the spring top plate (30) and the shearing box (27).

5. The cam forming machine shearing structure according to claim 1 or 2, characterized in that The transmission mechanism comprises a transmission shaft (14) for driving the shearing cam (21) to rotate, a transmission bevel gear (13) for driving the transmission shaft (14) to rotate, and a transmission gear (12), wherein the transmission gear (12) is provided with transmission power through the crankshaft (11).

6. The cam forming machine shearing structure according to claim 1 or 2, characterized in that The motion law of the shear stroke section of the acceleration characteristic curve in the shear cam curve satisfies the following function law: The movement of the feeding section of the shear mechanism push curve can still be expressed using the sine law as follows: The velocity and acceleration of the shear segment are: The speed and acceleration of the feeding section are:

7. The cam forming machine shearing structure according to claim 1 or 2, characterized in that The combination of the acceleration characteristic curve and the average speed characteristic curve in the shear cam curve satisfies the following function law: The displacement function of the combination rule: The speed function of the combination law: The acceleration function of the combination law:

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