Method for Detecting and Judging the Efficiency of the Overload Protection Device of the Flywheel of an Electric Press

Abstract

The present invention belongs to the technical field of electric presses, specifically a method for detecting and judging the effectiveness of a flywheel overload protection device of an electric press, including a flywheel slip-type overload protection device. The flywheel slip-type overload protection device is composed of an inner ring, an outer ring, a friction plate, a pressure ring, a tightening bolt and a disc spring. The inner ring is connected to the screw to drive the screw to rotate, and the outer ring is connected to the drive mechanism to drive the outer ring to rotate. The outer ring and the inner ring are connected by a friction plate, and also include an inner ring rack and an outer ring rack arranged on the inner ring and the outer ring. The present invention realizes real-time detection and judgment of the effectiveness of the flywheel slip-type overload protection device of the electric press, and can judge whether the impact force of the press is set correctly, which can effectively avoid the phenomenon that the press is damaged due to the failure of the overload device, thereby improving the service life of the press.

Description

Technical Field

[0001] The present invention relates to the technical field of electric presses, in particular to a method for detecting and judging the effectiveness of a flywheel overload protection device of an electric press. Background Art

[0002] Electric press is a commonly used die forging equipment in the forging industry. Its working principle is that the flywheel obtains and stores energy through gear transmission (gear-driven electric press) or belt transmission (belt-driven electric press), and then transmits it to the slider through the screw pair. The die installed on the slider acts on the workpiece to cause deformation of the workpiece. Due to improper selection of press working parameters, improper adjustment and use, or low heating temperature of the workpiece, it may be overloaded during operation. Overloading of the press will seriously damage the equipment and mold, such as bending or breaking of the screw, deformation of the frame, breakage of the frame tightening bolts, deformation of the worktable, cracking of the mold, etc. Therefore, the press is generally equipped with an overload protection device. The flywheel slip overload protection device is the most commonly used overload protection device for electric presses.

[0003] The existing presses equipped with flywheel slip overload protection devices have no detection mechanism. The effectiveness of the overload protection device is judged by the operator based on work experience. The vibration and impact of the press during operation are very large, and the tension bolts and disc springs of the overload protection device often become loose. At this time, the overload protection device fails, the flywheel will experience severe slippage, and the impact force of the press will be reduced. This fault does not cause much harm to the press, but it will cause unqualified parts in production. When the press parameters are improperly set and adjusted, or when the operator artificially increases the preload force of the disc spring to increase the impact force, the overload protection device will fail, the impact force of the press will be very large, and overload will damage the equipment and mold. In severe cases, it may even endanger the personal safety of the operator. For this reason, we propose a method for detecting and judging the effectiveness of the flywheel overload protection device of the electric press. Summary of the Invention

[0004] In view of the above problems and / or the problems existing in the methods for detecting and judging the effectiveness of flywheel overload protection devices of existing electric presses, the present invention is proposed.

[0005] Therefore, the purpose of the present invention is to provide a method for detecting and judging the effectiveness of the flywheel overload protection device of an electric press. The switch signals of the outer ring detection proximity switch and the inner ring detection proximity switch are collected respectively through a programmable controller, and the number of teeth rotated by the outer ring rack and the inner ring rack of the press from the beginning to the end of the impact are counted respectively, which can solve the above-mentioned existing problems.

[0006] To solve the above technical problems, according to one aspect of the present invention, the present invention provides the following technical solutions:

[0007] A method for detecting and determining the effectiveness of a flywheel overload protection device for an electric press includes: a flywheel slip-type overload protection device, the flywheel slip-type overload protection device comprising an inner ring, an outer ring, a friction plate, a pressure ring, a tension bolt, and a disc spring; the inner ring is connected to a screw to drive the screw to rotate; the outer ring is connected to a drive mechanism to drive the outer ring to rotate; the outer ring and the inner ring are connected via a friction plate; and the device further includes an inner ring rack and an outer ring rack provided on the inner ring and the outer ring;

[0008] An inner ring detection proximity switch is installed on the upper part of the inner ring rack, and an outer ring detection proximity switch is installed on the upper part of the outer ring rack. The inner ring detection proximity switch and the outer ring detection proximity switch are installed on a bracket, the bracket is fixed on a small crossbeam, and the small crossbeam is installed on a frame.

[0009] The method for detecting and judging the effectiveness of the flywheel overload protection device of the electric press includes the following steps:

[0010] Step 1: After the press is installed and debugged, use the hydraulic device to pre-tighten the disc spring and tension bolts, and record the pressure value of the hydraulic device;

[0011] Step 2: Adjust the striking force of the press to 1.6 times its nominal force, then perform a test strike and observe whether the slip angle difference Δθ between the outer and inner rings on the human-machine interface is equal to zero. If the value is greater than zero, indicating that slippage exists, then increase the hydraulic pressure appropriately according to the hydraulic pressure value recorded in step 1, re-pretighten the tensioning bolt, and record the hydraulic pressure again; if the slip angle difference Δθ is equal to zero, indicating that there is no slippage, then reduce the hydraulic pressure and re-pretighten. After repeated pretightening, adjust the pretightening several times until the tensioning bolt is pretightened and the outer ring just starts to slip at 1.6 times the nominal force of the press.

[0012] Step 3: Adjust the striking force of the press to 2 times its nominal force, conduct a test strike, and observe the slip angle difference Δθ on the human-machine interface. This value should be much larger than the slip angle difference at 1.6 times the nominal force. Save this value in the internal memory of the programmable controller through the human-machine interface and name it slip angle θ. This completes the calibration.

[0013] Step 4: After the calibration is completed, the slip angle θ value can be used to determine the effectiveness of the press overload protection device. The specific judgment method is that each time the press strikes, the programmable controller counts the gear pulses of the outer ring detection proximity switch and the inner ring detection proximity switch respectively, and calculates the angles θ1, θ2 and the angle difference Δθ of the outer ring and inner ring respectively. Then, the angle difference Δθ is compared with the calibrated slip angle θ, and the striking force at each strike is compared with the nominal force. Then, the internal program of the programmable controller automatically makes a judgment based on the slip efficiency and the working status of the press according to the overload protection device effectiveness judgment table, displays the working status of the press and the effectiveness of the overload protection device on the human-machine interface, and gives prompts and help information.

[0014] As a preferred solution of the method for detecting and judging the effectiveness of the electric press flywheel overload protection device described in the present invention, wherein: the installation and debugging of the flywheel slip-type overload protection device in step one requires the use of a hydraulic device to tighten the disc spring, and lock the pre-tightening force of the disc spring by tightening the bolt, so that a certain pressure is generated between the friction plate and the outer ring and the inner ring, so that when the outer ring rotates, the friction force can be used to drive the inner ring to rotate.

[0015] As a preferred solution of the method for detecting and judging the effectiveness of the flywheel overload protection device of the electric press according to the present invention, wherein: in the step 2, the slip angle difference Δθ is 0 0 within a smaller range than above.

[0016] As a preferred solution of the method for detecting and judging the effectiveness of the flywheel overload protection device of the electric press described in the present invention, wherein: in the step 2, the total number of teeth N1 of the outer ring rack and the total number of teeth N2 of the inner ring rack are input into the human-machine interface, and the programmable controller can automatically calculate the angle θ1 rotated by the outer ring and the angle θ2 rotated by the inner ring, and can calculate the difference Δθ between the outer ring angle θ1 and the inner ring angle θ2, and display these angle values on the human-machine interface.

[0017] As a preferred solution of the method for detecting and judging the effectiveness of the electric press flywheel overload protection device described in the present invention, the angle θ1 rotated by the outer ring is calculated by the formula: θ1=n1÷N1×360.

[0018] As a preferred solution of the method for detecting and judging the effectiveness of the electric press flywheel overload protection device described in the present invention, the angle θ2 rotated by the inner ring is calculated by the formula: θ2=n2÷N2×360.

[0019] As a preferred solution of the method for detecting and distinguishing the effectiveness of the electric press flywheel overload protection device described in the present invention, the difference Δθ between the outer ring angle θ1 and the inner ring angle θ2 is calculated by the formula: Δθ=θ1-θ2.

[0020] Compared with the existing technology: a programmable controller is used to collect the switch signals of the outer ring detection proximity switch and the inner ring detection proximity switch respectively, and the high-speed counter inside the programmable controller is used to count the number of teeth rotated by the outer ring rack and the inner ring rack of the press from the start to the end of the impact;

[0021] The number of teeth n1 rotated by the outer ring and the number of teeth n2 rotated by the inner ring can be displayed on the human-machine interface. The total number of teeth N1 of the outer ring rack and the total number of teeth N2 of the inner ring rack are input through the human-machine interface. To improve the detection accuracy, the total number of teeth of the two racks should be as large as possible. The programmable controller can then automatically calculate the angle θ1 rotated by the outer ring and the angle θ2 rotated by the inner ring 2, and the difference Δθ between the outer ring angle θ1 and the inner ring angle θ2, and display these angle values on the human-machine interface.

[0022] It realizes the real-time detection and judgment of the effectiveness of the flywheel slip-type overload protection device of the electric press, and can determine whether the impact force setting of the press is correct;

[0023] By adopting this method, the phenomenon of damage to the press due to failure of the overload device can be effectively avoided, thereby increasing the service life of the press;

[0024] This method monitors the impact force of the press and the slippage status of the flywheel, which can improve the performance and dimensional consistency of the workpieces produced and increase the yield rate. At the same time, this patent can also be used as a detection method for overload of the impact force of the press. When the impact force exceeds a certain set slippage angle, an alarm message is generated, thereby protecting the safety of the press. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 A schematic diagram of a slipping flywheel and its detection provided by the present invention;

[0026] Figure 2 A schematic diagram of the top view of the outer ring rack and the inner ring rack provided by the present invention;

[0027] Figure 3 This is a schematic diagram of the electrical circuit connection provided by the present invention.

[0028] In the figure: screw 1, inner ring 2, friction plate 3, pressure ring 4, tightening bolt 5, outer ring 6, disc spring 7, outer ring rack 8, outer ring detection proximity switch 9, inner ring detection proximity switch 10, inner ring rack 11, frame 12, bracket 13, small beam 14. DETAILED DESCRIPTION

[0029] To make the objectives, technical solutions and advantages of the present invention more clear, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0030] The present invention provides a method for detecting and judging the effectiveness of the flywheel overload protection device of an electric press. Figure 1-3 , including the following steps:

[0031] Step 1: After the press is installed and debugged, use a hydraulic device to pre-tighten the disc spring 7 and the tension bolt 5, and record the pressure value of the hydraulic device;

[0032] When the flywheel slip overload protection device is installed and debugged, it is necessary to use a hydraulic device to tighten the disc spring 7 and lock the pre-tightening force of the disc spring 7 through the tensioning bolt 5, so that a certain pressure is generated between the friction plate 3 and the outer ring 6 and the inner ring 2. In this way, when the outer ring 6 rotates, the inner ring 2 can be driven to rotate by the friction force. The hydraulic device uses the outer end face of an oil cylinder to fix the disc spring 7, and the piston rod of the oil cylinder is connected to the tensioning bolt 5 through its threaded connection. When the oil cylinder is loaded with pressurized oil, the tensioning bolt 5 is pulled out and the disc spring 7 is tightened. At this time, the two nuts of the tensioning bolt 5 are tightened to lock the disc spring 7. By adjusting the pressure of the hydraulic system, that is, the oil pressure of the oil cylinder, the purpose of adjusting the pre-tightening force of the disc spring 7 is achieved. The overload protection device effectiveness detection and judgment method needs to be calibrated before use. During calibration, the impact force detection device configured by the press is required to display the size of the impact force, and the pre-tightening force of the disc spring is adjusted by the hydraulic device.

[0033] Step 2: Adjust the striking force of the press to 1.6 times its nominal force, then try striking once, and observe whether the slip angle difference Δθ between the outer ring 6 and the inner ring 2 on the human-machine interface is equal to zero. If the value is greater than zero, it indicates that there is slippage. According to the hydraulic device pressure value recorded in step 1, appropriately increase the pressure of the hydraulic device, re-pretighten the tensioning bolt 5, and record the hydraulic pressure again; if the slip angle difference Δθ is equal to zero, it indicates that there is no slippage. Reduce the pressure of the hydraulic device and re-pretighten. After repeated adjustment of the pretightening, after the tensioning bolt is pretightened, at 1.6 times the nominal force of the press, the outer ring 6 just slips, and the slip angle difference Δθ is 0. 0 within a smaller range than the above;

[0034] The number of teeth n1 rotated by the outer ring 6 and the number of teeth n2 rotated by the inner ring 2 can be displayed on the human-machine interface. The total number of teeth N1 of the outer ring rack 8 and the total number of teeth N2 of the inner ring rack 11 are input through the human-machine interface. To improve the detection accuracy, the total number of teeth of the two racks is as large as possible. The programmable controller can then automatically calculate the angle θ1 rotated by the outer ring 6 and the angle θ2 rotated by the inner ring 2, and the difference Δθ between the outer ring angle θ1 and the inner ring angle θ2, and display these angle values on the human-machine interface.

[0035] The angle θ1 rotated by the outer ring 6 is calculated as follows: θ1=n1÷N1×360;

[0036] The angle θ2 rotated by the inner ring 2 is calculated as follows: θ2=n2÷N2×360;

[0037] The difference Δθ between the outer ring angle θ1 and the inner ring angle θ2 is calculated as follows: Δθ=θ1-θ2;

[0038] Step 3: Adjust the striking force of the press to 2 times its nominal force, conduct a test strike, and observe the slip angle difference Δθ on the human-machine interface. This value should be much larger than the slip angle difference at 1.6 times the nominal force. Save this value in the internal memory of the programmable controller through the human-machine interface and name it slip angle θ. This completes the calibration.

[0039] Step 4: After the calibration is completed, the slip angle θ value can be used to determine the effectiveness of the press overload protection device. The specific determination method is that each time the press strikes, the programmable controller counts the gear pulses of the outer ring detection proximity switch 9 and the inner ring detection proximity switch 10 respectively, and calculates the angles θ1, θ2 and the angle difference Δθ of the outer ring 6 and the inner ring 2 respectively, and then compares the angle difference Δθ with the calibrated slip angle θ, and compares the striking force at each strike with the nominal force, and then the internal program of the programmable controller automatically determines the slip efficiency and the working status of the press according to the overload protection device effectiveness judgment table, displays the working status of the press and the effectiveness of the overload protection device on the human-machine interface, and gives prompts and help information;

[0040]

[0041] Overload protection device effectiveness judgment table

[0042] The flywheel slip-type overload protection device is composed of an inner ring 2, an outer ring 6, a friction plate 3, a pressure ring 4, a tensioning bolt 5 and a disc spring 7. The inner ring 2 is connected to the screw 1 and can drive the screw 1 to rotate. The driving mechanism is connected to the outer ring 6 and can drive the outer ring 6 to rotate. The outer ring 6 and the inner ring 2 are connected by the friction plate 3. The outer ring 6 drives the inner ring 2 to rotate through friction. When the load of the press does not exceed the predetermined value, the outer ring 6 and the inner ring 2 are connected into one by friction, transferring the energy of the driving mechanism to the inner ring 2, which is then driven to rotate the screw 1, completing the energy transfer and the press working normally. When the load exceeds the predetermined value, the outer ring 6 slips, consumes energy, and reduces the impact force of the press, thereby achieving the purpose of overload protection.

[0043] The inner ring rack 11 and the outer ring rack 8 are respectively provided on the inner ring 2 and the outer ring 6. The sizes of the inner ring rack 11 and the outer ring rack 8 are determined according to the sizes of the inner ring 2 and the outer ring 6 of different press specifications. The number of teeth should be as large as possible to improve the detection accuracy. The inner ring detection proximity switch 10 is installed on the upper part of the inner ring rack 11, and the outer ring detection proximity switch 9 is installed on the upper part of the outer ring rack 8. The inner ring detection proximity switch 10 and the outer ring detection proximity switch 9 are installed on the bracket 13, the bracket 13 is fixed on the small crossbeam 14, and the small crossbeam 14 is installed on the frame 12. In this way, during the rotation of the flywheel, the inner ring detection proximity switch 10 and the outer ring detection proximity switch 9 remain stationary. During the striking process of the press, the two proximity switches respectively detect the number of teeth rotated by the inner ring 2 and the outer ring 6, thereby achieving the purpose of detecting the slipping state of the inner and outer rings;

[0044] The effectiveness detection and judgment method of the flywheel slip-type overload protection device of the electric press is used to realize real-time detection and judgment of the effectiveness of the flywheel slip-type overload protection device of the electric press, and it can be judged whether the impact force of the press is set correctly. The adoption of this method can effectively avoid the phenomenon of damage to the press due to failure of the overload device, thereby increasing the service life of the press. The monitoring of the impact force and flywheel slip state of the press by this method can improve the performance and dimensional consistency of the workpiece produced by it, and improve the yield rate. At the same time, this patent can also be used as a detection method for overload of the impact force of the press. When the impact force exceeds a certain set slip angle, an alarm message is generated, thereby protecting the safety of the press.

[0045] Although the present invention has been described above with reference to embodiments, various modifications may be made thereto and equivalent components may be substituted without departing from the scope of the present invention. In particular, as long as there are no structural conflicts, the various features of the embodiments disclosed herein may be combined with each other in any manner, and the omission of an exhaustive description of such combinations in this specification is solely for the sake of space and resource conservation. Therefore, the present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. An efficiency detection and discrimination device for an electric press flywheel overload protection device, comprising a flywheel slip-type overload protection device, wherein the flywheel slip-type overload protection device is composed of an inner ring (2), an outer ring (6), a friction plate (3), a pressure ring (4), a tension bolt (5) and a disc spring (7), wherein the inner ring (2) is connected to a screw rod (1) to drive the screw rod (1) to rotate, and the outer ring (6) is connected to a driving mechanism to drive the outer ring (6) to rotate, and the outer ring (6) is connected to the inner ring (2) via a friction plate (3), and is characterized in that: It also includes an inner ring rack (11) and an outer ring rack (8) arranged on the inner ring (2) and the outer ring (6); An inner ring detection proximity switch (10) is installed on the upper portion of the inner ring rack (11), and an outer ring detection proximity switch (9) is installed on the upper portion of the outer ring rack (8). The inner ring detection proximity switch (10) and the outer ring detection proximity switch (9) are installed on a bracket (13). The bracket (13) is fixed on a small crossbeam (14), and the small crossbeam (14) is installed on a frame (12).

2. A method for detecting and determining the effectiveness of a flywheel overload protection device for an electric press, characterized in that: The following steps are included: Step 1: After the press is installed and debugged, use a hydraulic device to pre-tighten the disc spring (7) and the tension bolt (5), and record the pressure value of the hydraulic device; Step 2: Adjust the striking force of the press to 1.6 times its nominal force, then perform a test strike and observe whether the slip angle difference Δθ between the outer ring (6) and the inner ring (2) on the human-machine interface is equal to zero. If the value is greater than zero, it indicates that there is slippage. According to the hydraulic pressure value recorded in step 1, appropriately increase the pressure of the hydraulic device, re-tighten the tension bolt (5), and record the hydraulic pressure again. If the slip angle difference Δθ is equal to zero, it indicates that there is no slippage. Reduce the pressure of the hydraulic device and re-tighten. After repeated adjustment of the pre-tightening, after the tension bolt is pre-tightened, the outer ring (6) just starts to slip at 1.6 times the nominal force of the press. Step 3: Adjust the striking force of the press to 2 times its nominal force, conduct a test strike, and observe the slip angle difference Δθ on the human-machine interface. This value should be much larger than the slip angle difference at 1.6 times the nominal force. Save this value in the internal memory of the programmable controller through the human-machine interface and name it slip angle θ. This completes the calibration. Step 4: After the calibration is completed, the slip angle θ value can be used to determine the effectiveness of the press overload protection device. The specific determination method is that each time the press strikes, the programmable controller counts the gear pulses of the outer ring detection proximity switch (9) and the inner ring detection proximity switch (10), respectively, and calculates the angles θ1, θ2 and the angle difference Δθ of the outer ring (6) and the inner ring (2), respectively. Then, the angle difference Δθ is compared with the calibrated slip angle θ, and the striking force at each strike is compared with the nominal force. Then, the internal program of the programmable controller automatically determines the slip efficiency and the working status of the press according to the overload protection device effectiveness judgment table, displays the working status of the press and the effectiveness of the overload protection device on the human-machine interface, and gives prompts and help information.

3. The method for detecting and judging the effectiveness of the flywheel overload protection device of the electric press according to claim 2, characterized in that: The installation and commissioning of the flywheel slip-type overload protection device in step 1 requires the use of a hydraulic device to compress the disc spring (7), and the pre-tightening force of the disc spring (7) is locked by tightening the bolt (5), so that a certain pressure is generated between the friction plate (3) and the outer ring (6) and the inner ring (2), so that when the outer ring (6) rotates, the inner ring (2) can be driven to rotate by the friction force.

4. The method for detecting and determining the effectiveness of the flywheel overload protection device of an electric press according to claim 2, characterized in that: In step 2, the slip angle difference Δθ is 0 0 within a smaller range than above.

5. The method for detecting and determining the effectiveness of the flywheel overload protection device of an electric press according to claim 2, characterized in that: In the step 2, the total number of teeth N1 of the outer ring rack (8) and the total number of teeth N2 of the inner ring rack (11) are input into the human-machine interface, and the programmable controller can automatically calculate the angle θ1 rotated by the outer ring (6) and the angle θ2 rotated by the inner ring (2), and can calculate the difference Δθ between the outer ring angle θ1 and the inner ring angle θ2, and display these angle values on the human-machine interface.

6. The method for detecting and judging the effectiveness of the flywheel overload protection device of the electric press according to claim 5, characterized in that: The angle θ1 rotated by the outer ring (6) is calculated as follows: θ1=n1÷N1×360.

7. The method for detecting and determining the effectiveness of the flywheel overload protection device of an electric press according to claim 5, characterized in that: The angle θ2 rotated by the inner ring (2) is calculated as follows: θ2=n2÷N2×360.

8. The method for detecting and determining the effectiveness of the flywheel overload protection device of an electric press according to claim 5, characterized in that: The difference Δθ between the outer ring angle θ1 and the inner ring angle θ2 is calculated as follows: Δθ=θ1-θ2.

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