Dynamic compensation method for bottom dead center position of punch press sliding block

Abstract

The invention discloses a dynamic compensation method for a bottom dead center position of a punch press sliding block, which is characterized in that an oil chamber is arranged between a connecting rod and a saw tooth, and a bottom dead center standard position and an allowable error range of the sliding block are set; performing preliminary test on a punch to obtain a linear expansion coefficient of the connecting rod; when the punching machine works, a bottom dead center position detection module detects the actual bottom dead center position of the sliding block in real time, when the actual bottom dead center position of the sliding block exceeds an allowable error, the real-time variation of the actual bottom dead center position at the moment is recorded, and the oil temperature difference needing to be adjusted is obtained through a linear expansion relational expression; the temperature of the oil chamber is adjusted until the actual bottom dead center position of the sliding block is within the allowable error range, and dynamic compensation of the bottom dead center position of the sliding block is completed; the method has the advantages that the position of the bottom dead center of the sliding block can be dynamically compensated in real time when the punching machine works, shutdown adjustment is not needed, the working efficiency is improved, and the position of the bottom dead center can be accurately, stably and reliably adjusted.

Description

Technical Field

[0001] The present invention relates to the technical field of punching presses, and particularly to a dynamic compensation method for the bottom dead center position of a punching press slider. Background Art

[0002] The accuracy of the bottom dead center position of a punching press slider refers to the deviation between the actual position and the ideal position when the slider moves to the lowest point during the operation of the punching press. It directly affects the forming accuracy of the punched products and is an important technical index of precision punching presses. The bottom dead center position accuracy is a dynamic accuracy, and there are many influencing factors, mainly including the thermal deformation of the punching press, the number of strokes per minute, and the comprehensive clearance. When the slider makes a reciprocating motion, an inertial force is generated on the slider. With different numbers of strokes per minute, the inertial force varies greatly, resulting in changes in the bottom dead center accuracy; during the stamping process, a large amount of frictional heat is generated at the kinematic pairs, causing components such as connecting rods, guide columns, and the machine body to elongate due to temperature rise, thereby shifting the bottom dead center position of the slider; in addition, excessive clearance will cause impact vibration of the kinematic pairs, resulting in changes in the bottom dead center position.

[0003] In order to improve the accuracy of the bottom dead center position of the slider, some achieve it by adjusting the mechanical mechanism to change the length of the connecting rod. For example, the Chinese invention patent with the patent number ZL201810121389.3 discloses a bottom dead center position compensation device for a slider, which changes the eccentricity in the vertical direction by rotating an eccentric shaft, causing the total length of the connecting rod to change, and realizing the micro-compensation of the bottom dead center position of the slider; the disadvantage of this method is that the eccentric shaft is located at the force center, and its own position is unreliable. After the adjustment is completed, a large locking force is required to lock the eccentric shaft, and the locking must be released by stopping the machine before adjustment. When adjusting in the forward and reverse directions, due to the existence of mechanism clearance, errors will inevitably occur, resulting in inaccurate adjustment accuracy; moreover, it cannot be adjusted during the stamping process, so real-time dynamic adjustment cannot be achieved. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a dynamic compensation method for the bottom dead center position of a punching press slider, which can perform real-time dynamic compensation on the bottom dead center position, and the adjustment is accurate, stable, and reliable.

[0005] The technical solution adopted by the present invention to solve the above technical problem is: a dynamic compensation method for the bottom dead center position of a punching press slider, including the following specific steps: (1) Set up an oil chamber between the connecting rod and the sawtooth, and install a temperature sensor on the connecting rod for measuring the oil temperature of the oil chamber; (2) Set the standard position of the bottom dead center of the slider and the allowable error range, and at the same time measure the initial oil temperature T of the oil chamber through the temperature sensor 0 ; (3) Conduct a preliminary test on the punching press to obtain the linear expansion coefficient α of the connecting rod; (4) The punching machine operates normally, and the lower dead point position detection module detects the actual lower dead point position of the slider in real time. When the actual lower dead point position of the slider exceeds the allowable error, record the real-time change amount ΔS of the actual lower dead point position at this time. 1 and through the linear expansion relation formula: , obtain the oil temperature difference ΔT to be adjusted, where: L 0 is the initial length of the connecting rod; (5) Quickly adjust the oil temperature of the oil chamber. When the temperature sensor detects that the target oil temperature T 1 reaches: T 1 = T 0 - ΔT, the temperature adjustment ends. At the same time, the lower dead point position detection module detects the actual lower dead point position of the slider in real time; (6) Repeat steps (4) and (5) until the actual lower dead point position of the slider is within the allowable error range, and complete the dynamic compensation of the lower dead point position of the slider.

[0006] Further, the oil chamber includes an upper oil chamber and a lower oil chamber, and the upper oil chamber and the lower oil chamber are connected through a groove. An oil inlet hole communicating with the upper oil chamber is provided at the upper end of the connecting rod, and an oil return hole communicating with the lower oil chamber is provided at the lower end of the connecting rod.

[0007] Further, a liquid level sensor is provided in the upper oil chamber.

[0008] Further, the method for adjusting the oil temperature of the oil chamber is: set an oil return tank and a temperature adjustment tank. The oil return tank is connected to the temperature adjustment tank, and the oil return tank is connected to the oil return hole and the temperature adjustment tank is connected to the oil inlet hole through oil pipes respectively. Adjust the oil temperature through the temperature adjustment tank and circulate and replace the oil in the oil chamber to achieve the adjustment of the oil temperature of the oil chamber.

[0009] Further, in step (3), the method for obtaining the linear expansion coefficient α of the connecting rod is: (3.1) The punching machine is initially tested, and the lower dead point position detection module detects the actual lower dead point position of the slider in real time. When the actual lower dead point position exceeds the allowable error, record the initial change amount ΔS of the actual lower dead point position at this time. 0 ; (3.2) The punching machine operates continuously, and at the same time, slowly reduce the oil temperature of the oil chamber until the actual lower dead point position of the slider is within the allowable error range, and record the oil temperature of the oil chamber at this time. ; (3.3) Through the relation formula: , calculate the initial oil temperature difference ΔT 0 , and then through the linear expansion relation formula: , obtain the linear expansion coefficient α of the connecting rod.

[0010] Furthermore, the initial change amount ΔS of the actual bottom dead center position 0 and the real-time change amount ΔS of the actual bottom dead center position 1 are both the differences between the actual bottom dead center position of the slider and its allowed maximum error.

[0011] Furthermore, the bottom dead center position detection module is a grating scale.

[0012] Compared with the prior art, the advantage of the present invention is that the real-time dynamic compensation of the bottom dead center position of the slider can be carried out during the operation of the punching machine by this method, without the need for shutdown adjustment, which improves the work efficiency, and the adjustment of the bottom dead center position is accurate, stable and reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 is a schematic diagram of the structural arrangement of the present invention on a punching machine; Figure 2 is a schematic diagram of the arrangement of the upper oil chamber and the lower oil chamber of the present invention between the connecting rod and the saw tooth; Figure 3 is Figure 2 the sectional view taken along A-A in DETAILED DESCRIPTION OF THE EMBODIMENTS

[0014] The present invention will be further described in detail below in conjunction with the embodiments of the drawings.

[0015] As Figures 1-3 shown, a dynamic compensation method for the bottom dead center position of a punching machine slider includes the following specific steps: (1), An upper oil chamber 3 and a lower oil chamber 4 are arranged between the connecting rod 1 and the saw tooth 2, and the upper oil chamber 3 and the lower oil chamber 4 are connected through a groove 5. An oil inlet hole 11 communicating with the upper oil chamber 3 is arranged at the upper end of the connecting rod 1, and an oil return hole 12 communicating with the lower oil chamber 4 is arranged at the lower end of the connecting rod 1. A temperature sensor 13 for measuring the oil temperature of the upper oil chamber 3 or the lower oil chamber 4 is installed on the connecting rod 1; In addition, an oil return tank 6 and a temperature control tank 7 are arranged. The oil return tank 6 is communicated with the temperature control tank 7, and the oil return tank 6 and the oil return hole 12, the temperature control tank 7 and the oil inlet hole 11 are respectively connected through oil pipes; (2), Set the standard position of the bottom dead center of the slider 8 and the allowed error range, and at the same time measure the initial oil temperature T of the upper oil chamber 3 or the lower oil chamber 4 through the temperature sensor 13 0 ; (3), The punching machine is initially run to obtain the linear expansion coefficient α of the connecting rod 1, specifically: (3.1), The punching machine is initially run, and the grating scale 9 detects the actual bottom dead center position of the slider 8 in real time. When the actual bottom dead center position exceeds the allowed error, record the initial change amount ΔS of the actual bottom dead center position at this time 0 ; (3.2) The punching machine operates continuously. Slowly adjust the oil temperature through the temperature control oil tank 7, and circulate and replace the oil in the upper oil chamber 3 and the lower oil chamber 4 to slowly reduce the oil temperature in the upper oil chamber 3 and the lower oil chamber 4 until the actual bottom dead center position of the slider 8 is within the allowable error range, and record the oil temperature in the upper oil chamber 3 and the lower oil chamber 4 at this time. ; (3.3) Through the relational expression: , calculate the initial oil temperature difference ΔT 0 , and then through the linear expansion relational expression: , obtain the linear expansion coefficient α of the connecting rod 1, where: L 0 is the initial length of the connecting rod 1; (4) The punching machine operates normally. The grating ruler 9 detects the actual bottom dead center position of the slider 8 in real time. When the actual bottom dead center position of the slider 8 exceeds the allowable error, record the real-time change amount ΔS of the actual bottom dead center position at this time 1 , and through the linear expansion relational expression: , obtain the oil temperature difference ΔT to be adjusted; (5) Quickly adjust the oil temperature in the upper oil chamber 3 and the lower oil chamber 4 through the temperature control oil tank 7. When the temperature sensor 13 detects that the target oil temperature T 1 reaches: T 1 = T 0 - ΔT, the temperature adjustment ends. At the same time, the grating ruler 9 detects the actual bottom dead center position of the slider 8 in real time; (6) Repeat steps (4) and (5) until the actual bottom dead center position of the slider 8 is within the allowable error range, and complete the dynamic compensation of the bottom dead center position of the slider 8.

[0016] In the above embodiment, the initial change amount ΔS 0 of the actual bottom dead center position and the real-time change amount ΔS 1 of the actual bottom dead center position are both the differences between the actual bottom dead center position of the slider 8 and its allowable maximum error. In addition, the grating ruler 9 can also be replaced by other existing displacement sensors.

[0017] In order to keep the oil volume in the upper oil chamber 3 and the lower oil chamber 4 stable, a liquid level sensor 10 can also be set in the upper oil chamber 3.

[0018] The protection scope of the present invention includes but is not limited to the above embodiments. The protection scope is subject to the claims. Any replacement, deformation, and improvement that are easily conceivable by those skilled in the art to this technology fall within the protection scope of the present invention.

Claims

1. A dynamic compensation method for the bottom dead point position of a punch press slide, characterized in that The specific steps include: (1) An oil chamber is provided between the connecting rod and the saw teeth, and a temperature sensor for measuring the oil temperature in the oil chamber is installed on the connecting rod; (2) Set the standard position of the bottom dead center of the slider and the allowable error range, and measure the initial oil temperature T0 of the oil chamber through the temperature sensor; (3) Initial test of the punch press to obtain the linear expansion coefficient α of the connecting rod; (4) When the punch press is working normally, the bottom dead point position detection module detects the actual bottom dead point position of the slider in real time. When the actual bottom dead point position of the slider exceeds the allowable error, the real-time change ΔS1 of the actual bottom dead point position is recorded, and the linear expansion relationship is used: , the oil temperature difference ΔT to be adjusted is obtained, where: L0 is the initial length of the connecting rod; (5) Rapidly adjust the oil temperature of the oil chamber. When the temperature sensor detects that the target oil temperature T1 reaches: T1 = T0-ΔT, the temperature adjustment ends. At the same time, the bottom dead point position detection module detects the actual bottom dead point position of the slider in real time. (6) Repeat steps (4) and (5) until the actual bottom dead point position of the slider is within the allowable error range, completing the dynamic compensation of the bottom dead point position of the slider.

2. A method for dynamic compensation of the bottom dead point position of a punch press slide according to claim 1, characterized in that: The oil chamber includes an upper oil chamber and a lower oil chamber, and the upper oil chamber and the lower oil chamber are connected by a groove. The upper end of the connecting rod is provided with an oil inlet hole connected to the upper oil chamber, and the lower end of the connecting rod is provided with an oil return hole connected to the lower oil chamber.

3. A method for dynamic compensation of the bottom dead point position of a punch press slide as claimed in claim 2, characterized in that: A liquid level sensor is arranged in the oiling chamber.

4. A method for dynamic compensation of the bottom dead point position of a punch press slide as claimed in claim 2, characterized in that: The method for regulating the oil temperature in the oil chamber is as follows: an oil return tank and a temperature regulating oil tank are provided, the oil return tank is connected to the temperature regulating oil tank, and the oil return tank and the oil return hole, and the temperature regulating oil tank and the oil inlet hole are respectively connected through oil pipes, the oil temperature is regulated by the temperature regulating oil tank, and the oil in the oil chamber is circulated and replaced to achieve the regulation of the oil temperature in the oil chamber.

5. A method for dynamic compensation of the bottom dead point position of a punch press slide as claimed in claim 1, characterized in that: In the step (3), the method for calculating the linear expansion coefficient α of the connecting rod is: (3.1) Initial test of the punch press: the bottom dead point position detection module detects the actual bottom dead point position of the slider in real time. When the actual bottom dead point position exceeds the allowable error, the initial test change ΔS0 of the actual bottom dead point position at this time is recorded; (3.2) The punch press continues to work, and the oil temperature in the oil chamber is slowly reduced until the actual bottom dead point position of the slider is within the allowable error range. Record the oil temperature in the oil chamber at this time. ; (3.3), through the relationship: , calculate the initial oil temperature difference ΔT0, and then use the linear expansion relationship: , and obtain the linear expansion coefficient α of the connecting rod.

6. A method for dynamic compensation of the bottom dead point position of a punch press slide as claimed in claim 5, characterized in that: The initial change ΔS0 of the actual bottom dead point position and the real-time change ΔS1 of the actual bottom dead point position are both the difference between the actual bottom dead point position of the slider and its maximum allowable error.

7. A method for dynamic compensation of the bottom dead point position of a punch press slide as claimed in claim 1, characterized in that: The bottom dead point position detection module is a grating ruler.

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