Large size high strength steel bar straightening machine and straightening method

Abstract

The invention discloses a large-size high-strength steel bar straightening machine and a straightening method. The straightening machine includes a frame, an upper roller group, a lower roller group and a transmission mechanism. The upper roller group includes an inlet pressure roller, a plurality of intermediate pressure rollers and an outlet pressure roller; wherein a signal monitor is arranged between the inlet pressure roller and the first intermediate pressure roller, and the first intermediate pressure roller and the second intermediate pressure roller are respectively provided with a vertical motion mechanism and a controller. During the straightening process, the signal monitor is linked with the vertical motion mechanism; the lower roller group includes an inlet support roller, a plurality of intermediate support rollers and an outlet support roller; the outer peripheral surface of each roller in the upper roller group and the lower roller group is provided with a corresponding straightening roller groove for conveying steel bars. According to the straightening machine and the straightening method of the invention, it can effectively prevent the occurrence of the jamming phenomenon during the straightening process of large-size high-strength steel bars.

Description

Technical Field

[0001] The invention relates to the field of material mechanical property testing, and in particular to a large-size high-strength steel bar straightening machine and a straightening method. Background Art

[0002] Before measuring the tensile strength and yield limit of steel bars in the laboratory, the steel bars need to be straightened to ensure the accuracy of the measurement.

[0003] The Chinese patent application with publication number CN109500298A discloses a laboratory high-strength round steel straightening machine and straightening method. By setting the central axis of the intermediate support roller to be gradually lower than the central axis of the entrance support roller first and then gradually higher than the central axis of the entrance support roller, a wave-like travel process is formed during the straightening process of the high-strength round steel, thereby greatly reducing the stress formed in the round steel. However, the applicant found in the specific experimental process that the straightening machine has a good effect when straightening steel bars with a diameter of less than 12mm, but when straightening large-size high-strength steel bars (diameter of more than 14mm, yield strength of more than 800MPa), see Figure 1 , the front end of the steel bar will bend upward after passing through the entrance roller. Since the diameters of the entrance roller, the middle roller and the exit roller are the same and the central axes are located in the same horizontal plane, the steel bar is easy to press against the middle roller during the forward movement, and often gets stuck. Although the middle roller of the straightening machine is equipped with a spring-type height fine-tuning structure, the adjustment height is limited and cannot effectively prevent the large-size high-strength steel bars from getting stuck.

[0004] In view of this, it is necessary to design a straightening machine that can effectively straighten large-size high-strength steel bars. Summary of the invention

[0005] The purpose of the present invention is to provide a steel bar straightening machine and a straightening method, which can effectively prevent the occurrence of a jamming phenomenon during the straightening process of large-size high-strength steel bars.

[0006] According to a first aspect of the present invention, there is provided a large-size high-strength steel bar straightening machine, comprising a frame, an upper roller group, a lower roller group and a transmission mechanism;

[0007] The upper roller group includes an inlet roller, a plurality of intermediate rollers and an outlet roller; wherein a signal monitor is provided between the inlet roller and the first intermediate roller, and the first intermediate roller and the second intermediate roller are provided with a vertical motion mechanism and a controller respectively. During the straightening process, the signal monitor is linked with the vertical motion mechanism. When the signal monitor detects the steel bar, it sends a signal to the controller. The controller calculates the time when the steel bar will reach the first and second intermediate rollers according to the set roller speed and roller spacing. The controller automatically controls the vertical motion mechanism to lift the first and second intermediate rollers upward in advance. When the steel bar passes through the vertical center axis of the first and second intermediate rollers, the controller controls the vertical motion mechanism to move the first and second intermediate rollers downward to a predetermined position to roll the steel bar.

[0008] The lower roller group includes an inlet support roller, a plurality of intermediate support rollers and an outlet support roller, the inlet support roller is aligned with the inlet pressure roller in the vertical direction, the plurality of intermediate support rollers are staggered with the plurality of intermediate pressure rollers, and the outlet support roller is aligned with the outlet pressure roller in the vertical direction;

[0009] The outer circumference of each roller in the upper roller group and the lower roller group is provided with a corresponding straightening roller groove for conveying steel bars.

[0010] Specifically, the transmission mechanism includes a motor, a motor drive wheel, a main drive wheel, and multiple reversing gears; a lower roller drive gear is provided at the outer end of each roller of the lower roller group, and adjacent lower rollers are connected to the reversing gear through the lower roller drive gear; the motor is arranged under the frame, the motor drive wheel is connected to the main drive wheel through a sprocket, the main drive wheel is coaxially arranged with a middle reversing gear, and upper roller drive gears are provided at the outer ends of the inlet pressure roller and the outlet pressure roller, respectively, and the upper roller drive gears of the inlet pressure roller and the outlet pressure roller are respectively meshed with the lower roller drive gears of the inlet support roller and the outlet support roller.

[0011] Preferably, the vertical movement mechanism is a hydraulic press and is equipped with a downward pressure sensor.

[0012] Furthermore, each roller of the upper roller group is provided with an initial position adjustment mechanism, and a sliding sleeve and a guide column are provided at both ends of each roller. The sliding sleeve is connected to the adjusting bolt or the vertical motion mechanism, and the sliding sleeve can move up and down along the guide column. Before straightening, the initial position of each roller is set by adjusting the bolt or the vertical motion mechanism.

[0013] Furthermore, the inlet pressure roller is fixed to the frame through a sliding sleeve, a guide column and an adjusting bolt, and a compression spring is arranged on the adjusting bolt to ensure the forward power of the sample.

[0014] Furthermore, the third and subsequent intermediate pressing rollers are provided with elastic supports, and during the steel bar straightening process, the intermediate pressing rollers can be fine-tuned through the elastic supports to prevent the steel bars from getting stuck.

[0015] Specifically, the outer peripheral surface of each roller in the upper roller group and the lower roller group is coaxially provided with four semicircular straightening roller grooves, and the radii are 7mm, 8mm, 9mm and 10mm respectively.

[0016] According to a second aspect of the present invention, a method for straightening large-size high-strength steel bars is provided, comprising the following steps:

[0017] (1) providing the large-size high-strength steel bar straightening machine described in the first aspect of the present invention, and adjusting the initial position of each roller of the upper roller group;

[0018] (2) starting the transmission mechanism so that each roller in the upper roller group and the lower roller group keeps running synchronously;

[0019] (3) The steel bar enters the straightening machine from the straightening roller groove between the inlet pressure roller and the inlet support roller;

[0020] (4) When the signal monitor detects the steel bar, it sends a signal to the controller. The controller calculates the time when the steel bar sample will reach the first and second intermediate pressing rollers according to the set roller speed and roller spacing. The controller automatically controls the vertical motion mechanism to lift the first and second intermediate pressing rollers upward in advance. When the steel bar passes through the vertical center axis of the first and second intermediate pressing rollers, the controller controls the vertical motion mechanism to move the first and second intermediate pressing rollers downward to a predetermined position to roll the steel bar;

[0021] (5) The steel bar continues to pass through the third and subsequent intermediate rollers and the exit roller in turn, and straightening is completed.

[0022] Furthermore, in step (4), the controller pre-sets the downward pressure of the first and second intermediate pressure rollers according to the material of the steel bar. During the straightening process, the controller controls the vertical motion mechanism to move to a suitable position according to the feedback signal of the downward pressure sensor.

[0023] The straightening machine and the straightening method according to the present invention can straighten high-strength and large-size steel bars, and can effectively prevent the occurrence of the jamming phenomenon during the straightening process of large-size high-strength steel bars. The stress generated during the straightening process is small, the straightening degree is high, and it can run automatically and continuously, which can meet the needs of mechanical property tests such as tensile strength and yield limit of high-strength round steel in the laboratory. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the front cross-section of the existing straightening machine mentioned in the background technology.

[0025] Figure 2 It is a schematic diagram of the main structure of a large-size high-strength steel bar straightening machine according to the present invention.

[0026] Figure 3 It is a side structural schematic diagram of a large-size high-strength steel bar straightening machine according to the present invention.

[0027] Figure 4 yes Figure 2 Schematic diagram of the cross-sectional structure in the BB direction.

[0028] Figure 5 yes Figure 2 Schematic diagram of the cross-sectional structure in the AA direction. DETAILED DESCRIPTION

[0029] The specific implementation of the large-size high-strength steel bar straightener of the present invention is described in detail below in conjunction with the accompanying drawings. Those skilled in the art should understand that the embodiments described below are only exemplary descriptions of the present invention and are not intended to limit it in any way.

[0030] The straightening machine of the present invention is mainly used for straightening the coiled specimens of circular cross-section metal materials, and is particularly suitable for round steel with a diameter of 14-20 mm. Such round steel has the characteristics of large specifications, high strength, and large surface stress. The existing straightening machine is prone to jamming. The length of the round steel sample used to test the tensile strength and yield limit in the laboratory is usually between 600-1000 mm.

[0031] Figure 2-5 A specific embodiment of the straightening machine of the present invention is shown. The straightening machine mainly comprises a frame 1, an upper roller group, a lower roller group and a transmission mechanism. The upper roller group and the lower roller group are respectively installed on the frame 1, and the transmission mechanism is used to drive the upper roller group and the lower roller group to operate.

[0032] See Figure 2 and Figure 4 The upper roller group includes an inlet pressure roller 11, a first intermediate pressure roller 12, a second intermediate pressure roller 13, a third intermediate pressure roller 14, and an outlet pressure roller 15. The diameters of the inlet pressure roller 11 and the outlet pressure roller 16 are the same, and the diameters of the three intermediate pressure rollers 12 may be the same as or different from the diameters of the inlet pressure roller 11 and the outlet pressure roller 16.

[0033] Each roller of the upper roller group is an adjustable pressure roller, and a sliding sleeve 41 and a guide column 42 are provided at both ends of each roller. The sliding sleeve 41 is connected to the adjusting bolt or the vertical motion mechanism, and the sliding sleeve 41 can move up and down along the guide column 42. Before straightening, the initial position of each roller is set by the adjusting bolt or the vertical motion mechanism, or the position is automatically adjusted by the vertical motion mechanism during the straightening process.

[0034] In a specific case, the adjustment mechanism of the entrance pressure roller 11 includes a sliding sleeve 41, a guide column 42 and a nut bolt 43, and the position is usually adjusted in the factory before leaving the factory. The entrance pressure roller 11 mainly provides appropriate friction for the sample. In order to ensure the forward power of the sample, a compression spring 44 is provided on the nut bolt 43. During the straightening process, the reaction force of the steel sample is resisted by the compression spring 44, thereby ensuring the forward power of the sample. The adjustment mechanism of the first intermediate pressure roller 12 and the second intermediate pressure roller 13 includes a sliding sleeve 41, a guide column 42 and a hydraulic press 4. The adjustment mechanism can not only adjust the initial position, but also automatically adjust during the straightening process, as further discussed below. The adjustment mechanism of the third intermediate pressure roller 14 and the outlet pressure roller 15 includes a sliding sleeve 41, a guide column 42 and a handle bolt 45. The handle bolt 45 can adjust the initial position of the third intermediate pressure roller 14 and the outlet pressure roller 15. In addition, an elastic support 44 is also provided at the bottom of the third intermediate pressure roller 14, which can be a spring. During the straightening process, when the steel bar passes through the third intermediate pressing roller 14, the spring can slightly push up the third intermediate pressing roller 14 to prevent jamming. The height of this fine adjustment is less than 10 mm.

[0035] See Figure 2 and Figure 5 The lower roller group includes an inlet support roller 21, four intermediate support rollers, and an outlet support roller 26. Each roller of the lower roller group is a fixed position roller. The diameters of the inlet support roller 21, the four intermediate support rollers, and the outlet support roller 26 are the same and the same as the diameters of the inlet pressure roller 11 and the outlet pressure roller 15. The four intermediate support rollers are divided into the first intermediate support roller 22, the second intermediate support roller 23, the third intermediate support roller 24, and the fourth intermediate support roller 25 according to the traveling direction of the steel bar.

[0036] Each roller in the upper roller group and the lower roller group is coaxially provided with four semicircular straightening roller grooves 5, with radii of 7mm, 8mm, 9mm and 10mm, respectively, for straightening round steel samples with diameters of 14mm, 16mm, 18mm and 20mm.

[0037] In the initial position, the inlet support roller 21 is aligned with the inlet pressure roller 11 in the vertical direction, the four intermediate support rollers are staggered with the three intermediate pressure rollers, and the outlet support roller 26 is aligned with the outlet pressure roller 15 in the vertical direction. The horizontal center axis of the third intermediate pressure roller 14 and the outlet pressure roller 15 are flush and both higher than the horizontal center axis of the inlet pressure roller 11. The horizontal center axis of the first intermediate support roller 22 is lower than the horizontal center axis of the inlet support roller 21, the horizontal center axis of the second intermediate support roller 23 is higher than the horizontal center axis of the first intermediate support roller 22 and the inlet support roller 21, the horizontal center axis of the third intermediate support roller 24 is higher than the horizontal center axis of the second intermediate support roller 23, the horizontal center axis of the fourth intermediate support roller 25 is higher than the horizontal center axis of the third intermediate support roller 24, and the horizontal center axis of the outlet support roller 26 is flush with the horizontal center axis of the fourth intermediate support roller 25. Through the above settings, the round steel is made to move slightly upward during the straightening process, which can effectively prevent the jamming of large-size high-strength steel bars and greatly reduce the stress formed in the round steel. In addition, the inventors have verified through repeated experiments that the height difference between the horizontal center axes of the adjacent pressure rollers or support rollers is controlled between 5-10 mm, the stress in the round steel is minimized, and the round steel will not rebound after straightening.

[0038] See Figure 2 and Figure 3 The transmission mechanism includes a motor 3, a motor transmission wheel 31, a main transmission wheel 32, and a plurality of reversing gears 35. A lower roller transmission gear 34 is provided at the outer end of each roller of the lower roller group, and the adjacent lower rollers are connected to the reversing gear 35 through the lower roller transmission gear 34. The motor 3 is arranged below the frame 1, the motor transmission wheel 31 is connected to the main transmission wheel 32 through a sprocket 33, the main transmission wheel 32 is coaxially arranged with a middle reversing gear 35, and an upper roller transmission gear 36 is provided at the outer ends of the inlet pressure roller 11 and the outlet pressure roller 15, respectively. The upper roller transmission gears 36 of the inlet pressure roller 11 and the outlet pressure roller 15 are meshed with the lower roller transmission gears 34 of the inlet support roller 21 and the outlet support roller 26, respectively. The transmission mechanism adopts gears and sprockets entirely, which can effectively transmit large torque, work stably, and will not slip and idle.

[0039] Both ends of each roller in the upper roller group and the lower roller group of the present invention are fixed to the bearing seat on the frame 1 through the central axis. During operation, the motor drive wheel 31 drives the driving wheel 32 to rotate, the driving wheel 32 drives a middle reversing gear 35 to rotate, and the reversing gear 35 drives the support rollers on both sides to rotate. Each support roller keeps rotating in the same direction through the reversing action of the reversing gear 35. The upper roller drive gears 36 of the inlet pressure roller 11 and the outlet pressure roller 15 are driven by the lower roller drive gears 34 of the inlet support roller 21 and the outlet support roller 26 to run in the opposite direction, and the three middle pressure rollers are in a free state.

[0040] A signal monitor 2 is provided between the entrance roller 11 and the first intermediate roller 12. The signal monitor 2 can be an infrared or laser sensor. The first intermediate roller 12 and the second intermediate roller 13 are provided with a hydraulic press 4 and a controller respectively. During the straightening process, the signal monitor 2 is linked with the hydraulic press 4. When the signal monitor 2 detects the steel bar, it sends a signal to the controller. The controller calculates the time when the steel bar will reach the first and second intermediate rollers according to the set roller speed and roller spacing. The controller automatically controls the hydraulic press 4 to lift the first and second intermediate rollers upward in advance. When the steel bar passes through the vertical center axis of the first and second intermediate rollers, the controller controls the hydraulic press 4 to move the first and second intermediate rollers downward to a predetermined position to roll the steel bar. The controller can be a common PLC controller. The hydraulic press 4 is equipped with a down pressure sensor.

[0041] The following specifically describes the process of straightening steel bars using the large-size high-strength straightener of the present invention, which includes the following steps:

[0042] (1) Adjust the initial position of each roller of the upper roller group of the straightening machine;

[0043] (2) starting the transmission mechanism so that each roller in the upper roller group and the lower roller group keeps running synchronously;

[0044] (3) The steel bar enters the straightening machine from the straightening roller groove between the inlet pressure roller and the inlet support roller;

[0045] (4) When the signal monitor detects the steel bar, it sends a signal to the controller. The controller calculates the time when the steel bar sample will reach the first and second intermediate pressing rollers according to the set roller speed and roller spacing. The controller automatically controls the hydraulic press to lift the first and second intermediate pressing rollers upward in advance. When the steel bar passes through the vertical center axis of the first and second intermediate pressing rollers, the controller controls the hydraulic press to move the first and second intermediate pressing rollers downward to a predetermined position to roll the steel bar;

[0046] (5) The steel bar continues to pass through the third intermediate roller and the exit roller in sequence, and straightening is completed.

[0047] In step (4), the controller pre-sets the downward pressure of the first and second intermediate pressure rollers according to the material of the steel bar. During the straightening process, the controller controls the hydraulic press to move to a suitable position according to the feedback signal of the downward pressure sensor.

[0048] After being straightened by the first intermediate roller and the second intermediate roller, the sample has a certain degree of straightness, so the sample will pass through the third intermediate roller and the exit roller smoothly; then the third intermediate roller and the exit roller give a certain amount of pressure and straightening, so that the sample can achieve the required straightness.

[0049] The straightening machine of the present invention optimizes and designs the existing straightening machine in order to solve the problems that occur when straightening large-sized and high-strength steel bars. It can effectively prevent the jamming phenomenon that occurs when straightening large-sized and high-strength steel bars, and has automatic operation and adjustment functions.

[0050] The above description is only a specific embodiment of the invention and is not intended to limit the invention in any way. Any changes and modifications made thereto according to the invention are within the scope of the technical protection scheme of this patent.

Claims

1. A large-size high-strength steel bar straightening machine, comprising a frame, an upper roller group, a lower roller group and a transmission mechanism, characterized in that: The upper roller group includes an inlet roller, a plurality of intermediate rollers and an outlet roller; wherein a signal monitor is provided between the inlet roller and the first intermediate roller, and the first intermediate roller and the second intermediate roller are provided with a vertical motion mechanism and a controller respectively. During the straightening process, the signal monitor is linked with the vertical motion mechanism. When the signal monitor detects the steel bar, it sends a signal to the controller. The controller calculates the time when the steel bar will reach the first and second intermediate rollers according to the set roller speed and roller spacing. The controller automatically controls the vertical motion mechanism to lift the first and second intermediate rollers upward in advance. When the steel bar passes through the vertical center axis of the first and second intermediate rollers, the controller controls the vertical motion mechanism to move the first and second intermediate rollers downward to a predetermined position to roll the steel bar. The lower roller group includes an inlet support roller, a plurality of intermediate support rollers and an outlet support roller, the inlet support roller is aligned with the inlet pressure roller in the vertical direction, the plurality of intermediate support rollers are staggered with the plurality of intermediate pressure rollers, and the outlet support roller is aligned with the outlet pressure roller in the vertical direction; The outer circumference of each roller in the upper roller group and the lower roller group is provided with a corresponding straightening roller groove for conveying steel bars; Each roller of the upper roller group is equipped with an initial position adjustment mechanism. Both ends of each roller are equipped with a sliding sleeve and a guide column. The sliding sleeve is connected to the adjusting bolt or the vertical motion mechanism. The sliding sleeve can move up and down along the guide column. Before straightening, the initial position of each roller is set by adjusting the bolt or the vertical motion mechanism. The intermediate pressing rollers after the third one are provided with elastic supports. During the steel bar straightening process, the intermediate pressing rollers can be fine-tuned through the elastic supports to prevent the steel bars from getting stuck.

2. The large-size high-strength steel bar straightening machine according to claim 1 is characterized in that: The transmission mechanism includes a motor, a motor drive wheel, a main drive wheel, and multiple reversing gears; a lower roller drive gear is provided at the outer end of each roller of the lower roller group, and adjacent lower rollers are connected to the reversing gear through the lower roller drive gear; the motor is arranged below the frame, the motor drive wheel is connected to the main drive wheel through a sprocket, the main drive wheel is coaxially arranged with a middle reversing gear, and upper roller drive gears are provided at the outer ends of the inlet pressure roller and the outlet pressure roller, respectively, and the upper roller drive gears of the inlet pressure roller and the outlet pressure roller are respectively meshed with the lower roller drive gears of the inlet support roller and the outlet support roller.

3. The large-size high-strength steel bar straightening machine according to claim 1 is characterized in that: The vertical movement mechanism is a hydraulic press and is equipped with a downward pressure sensor.

4. The large-size high-strength steel bar straightening machine according to claim 1, characterized in that: The outer circumference of each roller in the upper roller group and the lower roller group is coaxially provided with four semicircular straightening roller grooves, with radii of 7mm, 8mm, 9mm and 10mm respectively.

5. A method for straightening large-size high-strength steel bars, comprising the following steps: (1) Providing a large-size high-strength steel bar straightening machine as described in any one of claims 1 to 4, and adjusting the initial position of each roller of the upper roller group; (2) Start the transmission mechanism so that each roller in the upper roller group and the lower roller group keeps running synchronously; (3) The steel bar enters the straightening machine from the straightening roller groove between the entrance pressure roller and the entrance support roller; (4) When the signal monitor detects the steel bar, it sends a signal to the controller. The controller calculates the time when the steel bar sample will reach the first and second intermediate pressing rollers according to the set roller speed and roller spacing. The controller automatically controls the vertical motion mechanism to lift the first and second intermediate pressing rollers upward in advance. When the steel bar passes through the vertical center axis of the first and second intermediate pressing rollers, the controller controls the vertical motion mechanism to move the first and second intermediate pressing rollers downward to a predetermined position to roll the steel bar; (5) The steel bar continues to pass through the third and subsequent intermediate rollers and the exit roller in turn, and straightening is completed.

6. According to the straightening method of claim 5, in step (4), the controller pre-sets the downward pressure of the first and second intermediate pressure rollers according to the material of the steel bar, and during the straightening process, the controller controls the vertical motion mechanism to move to a suitable position according to the feedback signal of the downward pressure sensor.

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