Shearing structure of cam type forming machine

Abstract

The utility model discloses a shearing structure of a cam type forming machine, which comprises a shearing mechanism and a transmission mechanism, and is characterized in that the transmission mechanism controls the stroke track of a shear rod in the shearing mechanism through a shearing cam, and the extending stroke of the shearing cam consists of a shearing stroke and a shearing feeding stroke. A shearing cam curve for determining the shearing stroke is a curve for realizing the acceleration characteristic or a combination of the curve for realizing the acceleration characteristic and a uniform speed characteristic curve; according to the shearing structure of the cam type forming machine, the push rod can obtain various expected movement rules through the special cam curve of the shearing cam profile, response is fast, the mechanism is simple and compact, the shearing speed can be increased, a smoother material fracture can be obtained when materials are sheared, and the shearing efficiency is improved. The quality of upset products is improved; compared with a traditional shearing structure, the structure design is greatly simplified, the space size of a machine is optimized, the number of parts is reduced, the part design is simpler, and machining is convenient.

Description

TECHNICAL FIELD

[0001] The utility model relates to a kind of forming machine production technology, especially a cam type forming machine shearing structure. BACKGROUND

[0002] In the forming machine production of prior art, its shearing structure usually adopts eccentric connecting rod mode, and the shearing mode is complex in structure, large in space occupation, and has many parts, especially slow in shearing speed, which leads to uneven cut of the cut material. SUMMARY

[0003] The utility model discloses a cam type forming machine shearing structure with smooth cut after shearing and simple shearing structure.

[0004] To achieve the above object, the utility model provides a cam type forming machine shearing structure, which comprises a shearing mechanism and a transmission mechanism, characterized in that the transmission mechanism controls the stroke trajectory of the shear bar in the shearing mechanism through a shearing cam, the push stroke of the shearing cam is composed of a shearing stroke and a material feeding stroke, a rocker arm mechanism can be further arranged between the shearing mechanism and the transmission mechanism, the rocker arm mechanism comprises a rocker arm and a rocker arm shaft, first and second rollers are arranged at both ends of the rocker arm, and the first roller travels along the shearing cam curve; the second roller pushes the shear bar to travel through a contact block in the shearing mechanism.

[0005] The shearing mechanism comprises a shearing box and a shearing rod penetrating 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 tail 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.

[0006] 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 given transmission power by a crankshaft.

[0007] The cam type forming machine shearing structure provided by the utility model, when working, transmits to the transmission shaft through the crankshaft, the transmission gear and the transmission bevel gear, the shearing mechanism is driven by the shearing cam on the transmission mechanism, according to the arrangement condition and condition of the transmission mechanism, when the transmission shaft is near the shearing mechanism and the offset distance is very small, the shearing mechanism can be directly driven by the cam, the rocker arm mechanism is omitted, under the condition that the force on the cam is small, the torque acting on the cam is reduced, when the distance is larger, the shearing cam transmits the movement of the shearing cam to the shearing mechanism through the rocker arm in the rocker arm mechanism.

[0008] The cam type forming machine shearing structure provided by the utility model is characterized in that: on the function: the special cam curve of the shearing cam contour can make the push rod obtain various expected movement laws, and the response is fast, the mechanism is simple and compact, and the shearing speed can be accelerated, so that more flat material fracture can be obtained when shearing the material, and the quality of the upsetting product is improved.

[0009] The cam type forming machine shearing structure provided by the utility model is characterized in that: on the function: the special cam curve of the shearing cam contour can make the push rod obtain various expected movement laws, and the response is fast, the mechanism is simple and compact, and the shearing speed can be accelerated, so that more flat material fracture can be obtained when shearing the material, and the quality of the upsetting product is improved. BRIEF DESCRIPTION OF DRAWINGS

[0010] Figure 1 It is the position structure schematic view of the shearing cam in the transmission system;

[0011] Figure 2 It is the transmission relationship structure schematic view of the shearing cam and the shearing mechanism;

[0012] Figure 3 It is the phase relationship and basic curve schematic view of the shearing cam;

[0013] Figure 4 It is the push curve graph of the combined sinusoidal acceleration movement law;

[0014] Figure 5 It is the push curve graph of the combined sinusoidal acceleration and constant speed movement law.

[0015] Among them: crankshaft 11, transmission gear 12, transmission bevel gear 13, transmission shaft 14, shearing mechanism 17, shearing cam

[0016] 21, first roller 22, rocker arm 23, rocker shaft 24, second roller 25, shear bar 26, shear box 27, shear bar 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

[0017] The preferred embodiments of the present application 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 application, and are not used to limit the present application.

[0018] Example 1.

[0019] As shown in Figure 1 , Figure 2 , the present embodiment describes a cam type forming machine shear structure, comprising a shear mechanism 17 and a transmission mechanism, characterized in that the transmission mechanism controls the stroke trajectory of the shear bar 26 in the shear mechanism through the shear cam 21, the push stroke h of the shear cam 21 is composed of the shear stroke h1 and the material feeding stroke h2, a rocker arm mechanism can also be provided between the shear mechanism and the transmission mechanism, the shear cam 21 controls the stroke trajectory of the shear bar 26 in the shear mechanism by controlling the swing stroke of the rocker arm 23 in the rocker arm mechanism; the rocker arm mechanism includes a rocker arm 23 and a rocker shaft 24, a first roller 22 and a second roller 25 are respectively arranged at both ends of the rocker arm, the first roller 22 walks along the curve of the shear cam 21; the second roller 25 pushes the shear bar 26 to walk through the contact block 31 in the shear mechanism; the shear mechanism 17 includes a shear box 27 and a shear bar 26 penetrating through the shear box 27, a shear bar copper sleeve 28 is arranged on the shear bar 26, a shear knife seat 29 and a shear knife 291 are arranged at the front end of the shear bar 26; a spring top plate 30 and a contact block 31 in contact with the rocker arm mechanism are fixedly arranged at the tail end of the shear bar 26; a spring rod 32 and a return spring 33 for returning the shear bar 26 are arranged between the spring top plate 30 and the shear box 27; the transmission mechanism includes a transmission shaft 14 driving the shear cam 21 to rotate, and a transmission bevel gear 13 and a transmission gear 12 driving the transmission shaft 14 to rotate, the transmission gear 12 is given transmission power through the crankshaft 11.

[0020] When working, the crankshaft 11 transmits power to the transmission shaft 14 through the transmission gear 12 and the transmission bevel gear 13, the shear mechanism is driven by the shear cam 21 on the transmission mechanism, according to the arrangement and conditions of the transmission mechanism, when the transmission shaft is near the shear mechanism and the offset distance is small, the shear mechanism can be directly driven by the cam, and the rocker arm mechanism is omitted, in the case of small force on the cam, the torque acting on the cam is reduced; when the distance is larger, the shear cam 21 transmits the motion of the shear cam 21 to the shear mechanism 17 through the rocker arm 23 in the rocker arm mechanism. In practical application, the intermediate rocker arm mechanism is often used, such as Figure 2The length of the driving arm 1 and the driven arm 2 can be selected to change the size and force of the shearing cam 21, and facilitate the overall arrangement and design of the shearing cam 21.

[0021] When the forming machine is working, power is transmitted from the crankshaft in the transmission mechanism to each part of the system, and there is a strict phase relationship between the parts to ensure the coordination of each movement, which is determined by the working cycle diagram of the forming machine. The slide block mechanism is responsible for the upsetting forming of the blank. The upsetting blank is cut into segments of a certain size (length or volume) before upsetting by the material winding, and is delivered to the first station by the clamp.

[0022] If the crankshaft angle at the top dead center position of the slide block is 0°, the shearing mechanism must cut the material into the required blank before the slide block reaches the top dead center, and then deliver it to the first station by the clamp. When the moving die on the slide block contacts the blank, it is upset between the moving and stationary dies to form the initial first deformation, and then is delivered to the subsequent station by the clamp for continuous deformation until it is formed. Before the slide block reaches the top dead center, the shearing mechanism returns to the original position.

[0023] Conversely, from the analysis of a working cycle, the shearing mechanism will cut the material of a certain length delivered from the material winding and deliver it to the clamp pickup position (pickup station, often directly to the first station for nut machines) shortly after the slide block retreats. Then, the clamp picks up the blank from the shearing mechanism at the pickup station and delivers it to the upsetting station. After the blank is picked up by the clamp, the shearing mechanism can retreat. There is often a working time (phase) coordinated with the material feeding from the shearing to the retreat. This is the working phase relationship that the shearing cam design needs to consider, which is determined by the working cycle diagram of the overall design. Figure 3

[0024] 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 shearing cutter of the shearing mechanism approaches but does not affect the feeding of the straightened material, and is in the shearing position of the material of a certain length. The second stroke is the cutting stroke, which aims to cut the material with a diameter of d, and is the core of the shearing cam operation. The third stroke is the feeding stroke, which delivers the cut blank to the clamp pickup position (screw machines have a special pickup station, and nut machines often directly deliver to the first station).

[0025] The feeding stroke of the third stroke is often larger than the cutting stroke of the second stroke. The feeding stroke of large specification forming machines with large cutting diameters is also larger. The cutting stroke of the second stroke is theoretically the diameter of the sheared material, which is the maximum shearing diameter of the machine. The approach stroke is often small, and the position of the shearing cutter does not affect the feeding of the material when the shearing mechanism is in the original position, with a minimum theoretical value of approaching 0.​

[0026] The cam-type forming machine shearing structure provided by this utility model, in terms of function, optimizes the shearing performance of the shearing mechanism by studying the special curve of the disc cam to achieve the desired cam push stroke pattern, thereby obtaining high-quality sheared cross-sections. The return stroke of the shearing cam does not participate in the shearing process and is not analyzed in this utility model; commonly used motion law curves can be selected for design.

[0027] From a shearing perspective, the high speed of the shearing blade allows for a smoother cut when cutting wire, preventing burrs and flash from forming and resulting in better upsetting product quality.

[0028] There are two ways to increase the shearing speed: one is to increase the shearing speed when entering the material for shearing, by moving the shearing blade away from the wire at a certain position in the initial state, so that the shearing blade has a certain shearing speed when it enters the shearing process; the other is to continuously increase the speed of the shearing blade during the shearing motion.

[0029] The starting speed of the cam motion is usually 0. To increase the starting speed of shearing, the distance between the shearing tool and the wire needs to be increased, which will increase the stroke of the shearing mechanism. To increase the shearing speed during the shearing process, a cam profile curve with accelerated motion needs to be used.

[0030] After shearing, the cut blank is clamped at the cutting edge of the shearing blade and continues to be fed forward with the movement of the shearing mechanism. Normally, the clamping position and the position of the clamping force in the forming machine remain relatively constant. However, when the length of the material being sheared varies, excessive acceleration or deceleration can cause the clamped blank to become skewed, affecting its posture during subsequent clamping and feeding. Therefore, the feeding speed of the shearing mechanism during its feeding stroke should not be too fast, and acceleration and deceleration should not change drastically.

[0031] An ideal shearing stroke curve for a forming machine cam should have a high shearing speed during the shearing process to quickly shear the material and improve the quality of the shear cut. At the end of the shearing process, it should not still be in an accelerated state, but rather in a state of maximum speed or close to maximum speed, and in a state of deceleration.

[0032] In cam curve design, cosine acceleration and sine acceleration motion laws are frequently used. The basic characteristic of these two curves is that the motion speed is continuous, and the maximum speed occurs at the midpoint of the entire push stroke. This means that regardless of whether a sine or cosine acceleration motion law is chosen, in the actual shearing process, the maximum speed is reached after shearing is completed. The maximum speed does not play a role in improving the quality of the sheared surface during shearing. During the feeding of the sheared billet, there is still an initial acceleration followed by deceleration, affecting the quality of billet delivery.

[0033] The return stroke of the shearing cam has no specific requirements, and only needs to return to the starting point of the movement within a specified time to prepare for the next shearing. The focus of the shearing cam of the forming machine is to optimize the push stroke curve to improve the shearing quality of the material.

[0034] The cam curve design of the utility model selects a combined curve meeting the shearing and feeding quality requirements

[0035] As described above, the approach stroke of the shearing mechanism movement is usually small, the shearing stroke is to cut the wire, and the size is the maximum shearing diameter set by the forming machine. The feeding stroke depends on the overall design requirements of the forming machine (nut machine or screw machine). Regardless of which aspect is considered, the feeding stroke will be greater than the shearing stroke. Since the approach stroke is small, the main consideration in the cam curve design is the two strokes, i.e. the cutting stroke and the feeding stroke. According to the operation requirements and stroke size of the two strokes, a suitable curve combination is selected.

[0036] The push stroke h of the cam is composed of the shearing stroke h1 and the feeding stroke h2:

[0037] h = h1 + h2

[0038] In order to make the designed cam curve meet the special requirements of shearing, the shearing stroke is taken as:

[0039] h1 = d

[0040] The feeding stroke is:

[0041] h2 ≥ d

[0042] In the formula, d is the shearing diameter required by the forming machine.

[0043] In order to obtain better shearing surface quality, the speed in the shearing process should be as large as possible, so the curve that realizes the acceleration characteristics in the shearing stroke can meet the requirements, such as the constant acceleration law, the sine law, the cosine law, etc.

[0044] In this embodiment, two different sine laws are combined. In the shearing stroke, the sine law is adopted, which gradually increases the speed in the entire shearing process, and it is an acceleration process. The acceleration gradually increases at the beginning, reaches the maximum at the middle of the stroke, and then decreases in the latter half, and the acceleration is 0 when cutting, and the speed reaches the maximum.

[0045] The movement law of the shearing stroke segment of the shearing mechanism push stroke curve can be expressed as:

[0046]

[0047] The motion of the feed section of the shearing mechanism push curve can be expressed as:

[0048]

[0049] In the shearing stroke section δ, the change range is 0 ~ δ 01 , the whole stroke is 0 ~ h1(d).

[0050] In the feed stroke section δ, the change range is δ 01 ~ δ0, the rotation angle δ 02 = δ0- δ 01 , the whole stroke is h1(d) ~ h.

[0051] The first and second derivatives of the above two motion laws are taken respectively to obtain the speed and acceleration as follows,

[0052] The speed and acceleration of the shearing section are:

[0053]

[0054] The speed and acceleration of the feed section are:

[0055]

[0056] In the entire cam push section,

[0057] When δ = 0, h = 0, v = 0, a = 0

[0058] When δ = δ 01 ,

[0059] At the end of the shearing stroke section, h = h1, a = 0

[0060] At the beginning of the feed stroke section, h = h1, a = 0

[0061] When δ = δ0= δ 01 + δ 02 , h = h1+h2, v = 0, a = 0

[0062] From the push law of the cam, the displacement, speed and acceleration must be continuous, therefore, at the conversion point of the end of shearing and the beginning of feed, that is:

[0063] When δ = δ 01 , it should be

[0064] The relationship between lift and rotation angle must meet the condition:

[0065]

[0066] That is, the lift and the rotation angle are segmented in linear relationship, and the curve of two different sinusoidal rules is obtained. The displacement, velocity and acceleration relationship is shown in the following figure. Figure 4 .

[0067] When h1 = h2, it is a typical sinusoidal rule.

[0068] In this embodiment, when h1 = d, the speed of the cam is continuously accelerated in the process of cutting the wire, and the acceleration is also increased first, and then the acceleration is decreased. The speed reaches the maximum at the end of the cutting, and the positive acceleration decreases to 0; in the subsequent feeding process, the acceleration is negative, and the speed gradually decreases until the end of the feeding process, and the speed and acceleration are both 0.

[0069] Considering the influence of the approach stroke of the cam, the cam is selected at h1 = d, and the cutting mechanism has not cut all the wire when the cam reaches the maximum speed and the positive acceleration decreases to 0. There is a certain amount of residual corresponding to the approach stroke. In the part of the wire cutting residual section, the cam curve enters the next segment of the sinusoidal rule of negative acceleration, and the feeding segment is large, and the deceleration is slow. The speed when cutting the remaining material part is close to the maximum speed, which meets the requirement that the cutting speed of the cam design should be as fast as possible, and the feeding speed should be slow, which is still an ideal result. In the subsequent feeding process, the feeding speed continues to decrease until the speed is 0 when feeding to the first work position or the clamping position of the clamp.

[0070] Embodiment 2

[0071] The cutting of various materials has its own suitable cutting speed, and the cutting speed of embodiment 1 reaches its cutting speed at the end of cutting, which has a gap with the ideal cutting requirement. It is required to further accelerate in the early stage of the cutting stroke to reach the required speed as soon as possible.

[0072] In this embodiment, the speed is accelerated in the early stage of the cutting stroke, and the required speed is reached at the required speed. Similarly, the stroke of the cutting segment is set to the diameter d of the material to be cut. The stroke of the acceleration segment is smaller than the diameter d of the material, and h1 is 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 feeding process of the cam is h0, and the following is obtained:

[0073] h1 < d (such as d / 2)

[0074] h1 + h2 = d

[0075] h1 + h2 + h3 = h0

[0076] Similarly, the sinusoidal rule is selected as the contour curve of the cam feeding process in the front and rear two segments, and the constant speed polynomial motion rule is used in the middle segment. The motion rules of the three segments of the contour are expressed as:

[0077] Combined regular displacement function:

[0078]

[0079] Combined regular velocity function:

[0080]

[0081] Combined regular acceleration function:

[0082]

[0083] When δ = δ 01 , h = h1, or a = 0;

[0084] When δ = δ 02 , h = h1 + h2, or a = 0;

[0085] When δ = δ0, h = h1 + h2 + h3, v = 2h3ω, a = 0;

[0086] The velocity continuity condition is satisfied:

[0087]

[0088] That is, the relationship must be satisfied:

[0089]

[0090] or

[0091]

[0092] The displacement, velocity and acceleration diagrams of the push stroke section composed of the three curves are shown in Figure 5 .

[0093] Similarly, the push stroke motion law of the shear cam can be selected according to the work requirements, and other basic motion laws, such as cosine law, constant acceleration and constant deceleration motion law, can be combined and implemented.

[0094] Finally, it should be noted that the above only describes the preferred embodiments of the present application and is not intended to limit the present application. Although the present application 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 modification, equivalent substitution, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A shearing structure for a cam-type forming machine, comprising a shearing mechanism and a transmission mechanism, characterized in that: The transmission mechanism controls the travel trajectory of the scissor bar (26) in the shearing mechanism through the shearing cam (21). The push stroke of the shearing cam (21) consists of the shearing stroke and the material feeding stroke. A rocker arm mechanism is also provided between the shearing mechanism and the transmission mechanism. The rocker arm mechanism includes a rocker arm (23) and a rocker arm shaft (24). A first roller (22) and a second roller (25) are respectively provided at both ends of the rocker arm (23). The first roller (22) travels along the curve of the shearing cam (21). The second roller (25) pushes the scissor bar (26) to travel through the contact block (31) in the shearing mechanism.

2. The cam-type forming machine shearing structure according to claim 1, characterized in that: The shearing mechanism includes a shearing box (27) and a shearing rod (26) passing through the shearing box (27). A shearing rod copper sleeve (28) is provided on the shearing rod (26). A shearing blade holder (29) and a shearing blade (291) are provided at the front end of the shearing rod (26). A spring top plate (30) and a contact block (31) that contacts the rocker arm mechanism are fixedly provided at the tail 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).

3. The cam-type forming machine shearing structure according to claim 1 or 2, characterized in that: The transmission mechanism includes a transmission shaft (14) that drives the shearing cam (21) to rotate, and a transmission helical gear (13) and a transmission gear (12) that drive the transmission shaft (14) to rotate. The transmission gear (12) provides transmission power through the crankshaft (11).

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