A layer-by-layer welding seam grinding method for automatic rail grinding equipment

Abstract

The present invention relates to a layer-by-layer grinding weld seam grinding method of an automatic rail grinding device, comprising: S1, determining the operating range of the automatic grinding device on the track according to the weld position; S2, using a grinding head to collide with the track to realize collision detection of each position of the track, determine the height of the top surface of the track parent material, the position of the edges on both sides of the weld and the height of the weld vertex, determine the grinding range according to the position of the edges on both sides of the weld, and determine the weld thickness according to the height difference between the weld vertex and the track parent material; S3, according to the weld thickness, set the single grinding thickness of the grinding head, determine the number of reciprocating grindings, set the automatic grinding device to reciprocate to realize single-angle grinding; S4, rotate the grinding head multiple times to change the angle of the grinding head relative to the track, repeat the above steps S2 and S3 after each rotation of the grinding head to complete the grinding of the corresponding angle, and the angle range of the grinding head rotation is ±90°. The present invention can realize the precise positioning of the rail weld and improve the quality and efficiency of weld grinding.

Description

Technical Field

[0001] The invention relates to the technical field of track maintenance, in particular to a layer-by-layer welding seam grinding method of automatic rail grinding equipment. Background Art

[0002] With the increase in railway mileage and transportation density, the replacement of old rails and switches has become more frequent. When replacing rails, both ends need to be welded, and the smoothness of the weld directly affects the quality of train operation. The development of high-speed railways has put forward higher requirements on the smoothness and internal quality of rail welds.

[0003] At present, when replacing tracks, the rails are usually welded by thermite welding, which will leave a relatively thick weld. The grinding equipment currently used is a profile grinder, which relies entirely on the experience of the grinders. The main problems are low grinding efficiency, extreme dependence on technical experience, unstable results, poor precision, etc. To obtain a better grinding effect, a single weld requires at least twenty minutes. With the shortening of the work window period, manual grinding gradually cannot meet the work requirements when the number of operators remains unchanged. The traditional automated grinding method adopts a position mode and cannot be adjusted according to the actual situation of the weld. Due to problems such as equipment rigidity, the weld cannot be completely removed and the smoothness of the rail cannot be guaranteed.

[0004] Therefore, it is urgent to study a grinding method for automated rail weld grinding equipment that can meet daily rail replacement needs in order to adapt to the development needs of high-speed railways. Summary of the invention

[0005] To this end, the technical problem to be solved by the present invention is to overcome the problem in the prior art that during the operation of the rail weld grinding equipment, the grinding head is lifted up due to the large grinding amount and limited equipment rigidity, resulting in large weld residue. The present invention provides a layer-by-layer grinding method for rails, which can achieve accurate positioning of rail welds and judgment of grinding residues, thereby improving the quality and efficiency of weld grinding.

[0006] In order to solve the above technical problems, the present invention provides a layer-by-layer weld grinding method of an automatic rail grinding device, comprising the following steps:

[0007] S1. Determine the operating range of the automatic grinding equipment on the track according to the weld position;

[0008] S2. Use the grinding head to collide with the rail to realize collision detection of various positions of the rail, determine the height of the top surface of the rail parent material, the positions of the edges on both sides of the weld and the height of the weld vertex, determine the grinding range according to the positions of the edges on both sides of the weld, and determine the weld thickness according to the height difference between the weld vertex and the rail parent material;

[0009] S3. According to the weld thickness, set the single grinding thickness of the grinding head, determine the number of reciprocating grinding, and set the automatic grinding equipment to reciprocate to achieve single-angle grinding;

[0010] S4, rotating the grinding head multiple times to change the angle of the grinding head relative to the track, and repeating the above steps S2 and S3 after each rotation of the grinding head to complete the grinding of the corresponding angle. The rotation angle range of the grinding head is ±90°.

[0011] In one embodiment of the present invention, in step S2, the collision detection method comprises the following steps:

[0012] Step S2-1, move the grinding head to the rail base material on both sides of the weld respectively, control the movement of the grinding head toward the rail base material, and control the feed amount of each movement. After each movement, analyze whether the grinding head is in contact with the rail base material through the collision detection unit until the grinding head is in contact with the rail base material, stop feeding, determine the feed amount, and measure the height of the top surface of the rail base material;

[0013] Step S2-2, maintaining the height of the grinding head in step S2-1, controlling the grinding head to move from both sides of the weld toward the weld, and analyzing whether it is in contact with the weld edge through the collision detection unit during the movement, until the grinding head is in contact with the weld edge, stopping the movement, and measuring the positions of the edges on both sides of the weld;

[0014] Step S2-3, move the grinding head to the top of the weld, control the movement of the grinding head toward the weld, and control the feed amount of each movement. After each movement, analyze whether there is contact with the weld through the collision detection unit until the grinding head contacts the weld, stop feeding, determine the feed amount, and measure the height of the top surface of the weld.

[0015] In one embodiment of the present invention, in step S2, the grinding range is extended by 5 to 10 mm to both sides according to the positions of the edges on both sides of the weld.

[0016] In one embodiment of the present invention, the single grinding thickness determined in step S3 does not exceed 2 mm.

[0017] In one embodiment of the present invention, in step S3, the automatic grinding equipment is set to grind at a uniform speed, and the grinding speed is 15-25 mm / s.

[0018] In one embodiment of the present invention, when the last reciprocating grinding in step S3 is completed, the grinding power is detected, and a fluctuation threshold of the fluctuation range and fluctuation time of the grinding power is set. When the grinding power exceeds the threshold, the last grinding is repeated until the fluctuation range and fluctuation time of the grinding power are within the fluctuation threshold.

[0019] In one embodiment of the present invention, in step S4, when the grinding head angle is rotated, the residual height of the welding material between two adjacent grindings does not exceed 0.25 mm.

[0020] In one embodiment of the present invention, it also includes:

[0021] Step S5, fine grinding the rail. According to the existing grinding range, the rail is extended to both sides of the grinding range by 250 to 350 mm. The position of the grinding head is re-determined by the collision between the grinding head and the rail. The position of the grinding head is pressed down by 0.02 mm as the basis for fine grinding, so as to achieve single-angle fine grinding.

[0022] Step S6, rotating the grinding head multiple times to change the angle of the grinding head relative to the track, repeating the above step S5 after each rotation of the grinding head to complete the fine grinding of the corresponding angle, and the rotation angle range of the grinding head is ±90°.

[0023] In one embodiment of the present invention, in step S6, grinding is started from -90°, and grinding is performed every 5°, and grinding is performed every 2° between -10° and 45°.

[0024] In order to solve the above technical problems, the present invention also provides an automatic rail grinding device, which can complete the above layer-by-layer weld grinding method, including:

[0025] Reciprocating drive unit, which realizes reciprocating movement in the working area on both sides of the welding position;

[0026] The grinding unit is arranged on the reciprocating drive unit and includes a grinding head, which is driven by the reciprocating drive unit to detect the position and height of the weld and complete the grinding of the weld;

[0027] The corner unit is arranged on the reciprocating driving unit and connected with the grinding unit to drive the grinding head of the grinding unit to rotate relative to the track.

[0028] The above technical solution of the present invention has the following advantages compared with the prior art:

[0029] The layer-by-layer weld grinding method of the rail automatic grinding equipment of the present invention realizes the position detection of the weld before grinding, adopts the collision between the grinding head and the rail, realizes the collision detection of each position of the rail through the collision detection principle, determines the height of the top surface of the rail parent material, the position of the edges on both sides of the weld and the height of the weld vertex, determines the grinding range according to the position of the edges on both sides of the weld, determines the weld thickness according to the height difference between the weld vertex and the rail parent material, sets the grinding amount each time according to the weld thickness, and calculates the number of reciprocating times of the automatic grinding equipment;

[0030] By adopting the above-mentioned layer-by-layer weld grinding method, the reciprocating path of the equipment each time and the grinding size of the feed after each reciprocating movement can be accurately calculated, which can achieve precise positioning of the rail weld and improve the weld grinding quality and efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to make the content of the present invention more clearly understood, the present invention is further described in detail below according to specific embodiments of the present invention in conjunction with the accompanying drawings, wherein

[0032] Figure 1 It is a flow chart of the steps of the layer-by-layer weld grinding method of the rail automatic grinding equipment of the present invention;

[0033] Figure 2 It is a schematic diagram of the operation range of the automatic grinding equipment of the present invention;

[0034] Figure 3 It is a working principle diagram of the collision detection of the present invention;

[0035] Figure 4 It is a structural schematic diagram of collision detection of various positions of the track by the automatic grinding equipment of the present invention;

[0036] Figure 5 It is a schematic structural diagram of the rotating grinding head of the present invention to change the angle of the grinding head relative to the track;

[0037] Figure 6 It is a structural schematic diagram of the automatic rail grinding equipment of the present invention.

[0038] Explanation of the reference numerals in the specification: 1. reciprocating drive unit; 2. grinding unit; 21. grinding head; 3. corner unit. DETAILED DESCRIPTION

[0039] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0040] In the process of track maintenance, the rails are welded by thermite welding, which will leave a relatively thick weld. In order to eliminate the weld, the prior art uses automatic rail grinding equipment to grind the rail weld and achieve smooth docking of the rails. The operating method of the prior art automatic rail grinding equipment is: manual visual observation is used to achieve tool alignment of the grinding head, and whether to grind the weld is determined based on the amount of sparks during grinding. There is no control over the amount of cutting for each grinding, resulting in the inability to completely remove the weld. Sometimes the removal amount is too large, so the smoothness of the rail cannot be guaranteed.

[0041] Example 1

[0042] Reference Figure 1 As shown, in order to solve the above problems, the present invention transforms the existing rail automatic grinding equipment and proposes a new weld grinding method, which includes the following steps:

[0043] S1. Determine the operation range;

[0044] Determine the operating range of the automatic grinding equipment on the track according to the weld position. Since the automatic grinding equipment needs to run on the track and perform grinding during operation, it is necessary to reserve a certain operating range and operation preparation range on the track. Figure 2 As shown, the working range includes working endpoints X1 and X2 arranged on both sides of the weld, and the working preparation area includes working preparation endpoints Y1 and Y2 arranged outside the working range. The automatic grinding device is first moved to the working preparation range, and debugging is completed in the working preparation range. In the working range, only the automatic grinding device is allowed to reciprocate, and no other equipment will interfere with the running trajectory of the automatic grinding device. The working range needs to completely cover the weld. On the premise of meeting the comprehensive grinding requirements of the weld, the working range is shortened as much as possible, unnecessary moving distance is reduced, and the overall reciprocating operation efficiency is increased. Therefore, in this embodiment, a larger working range is first determined to ensure that the entire automatic grinding device can move completely on both sides of the weld, and then the precise working range is determined by the position of the grinding head according to the needs of subsequent different grinding processes.

[0045] S2, collision detection;

[0046] The grinding head collides with the rail to realize collision detection of various positions of the rail, determine the height of the top surface of the rail parent material, the position of the edges on both sides of the weld and the height of the weld vertex, determine the grinding range according to the position of the edges on both sides of the weld, and determine the weld thickness according to the height difference between the weld vertex and the rail parent material;

[0047] Reference Figure 3As shown, the working principle of the collision detection adopted in this embodiment is as follows: the grinding head as an actuator needs to be electrically connected to the driving mechanism, and the driving mechanism will monitor the working parameters of the grinding head, including the rotation speed of the grinding head, the rotation power of the grinding head, the current and voltage changes when the grinding head is working, etc. When the grinding head contacts the track, the current detected on the driving mechanism changes due to the force applied to the grinding head. By utilizing this characteristic, collision detection can be realized. First, a current collision detection threshold is set, so that the grinding head gradually feeds a small amount toward the component to be detected, and analyzes whether there is a change in current. When the current exceeds the threshold, it can be determined that the component to be detected is in contact. When the current does not change, the component to be detected can be continuously fed a small amount until it contacts the component to be detected. In addition, in order to protect the grinding head, a feeding limit value can also be set. When the limit value is exceeded, the feeding action is terminated, indicating that the component to be detected has not been contacted.

[0048] Specifically, refer to Figure 4 As shown in the figure, to determine the specific position of a weld, two pieces of information need to be obtained: (1) the two side boundaries of the weld (point D and point E); (2) the thickness of the weld. The thickness of the weld can be calculated by the height difference between the weld vertex F and the rail base material C. Therefore, the collision detection method needs to detect the positions of the above four points C, D, E, and F. The specific detection steps are as follows:

[0049] Step S2-1, move the grinding head to the rail base material on both sides of the weld respectively, control the movement of the grinding head toward the rail base material, and control the feed amount of each movement. After each movement, analyze the change of current through the collision detection unit until the current exceeds the threshold value, indicating that the grinding head is in contact with the rail, stop feeding, determine the feed amount, and measure the height of the top surface of the rail base material C;

[0050] Step S2-2, maintaining the height of the grinding head in step S2-1, controlling the movement of the grinding head toward the weld, analyzing the change of the current through the collision detection unit during the movement, until the current exceeds the threshold, indicating that the grinding head is in contact with the edge of the weld, stopping the movement, and measuring the positions of the edges on both sides of the weld (point D and point E);

[0051] Step S2-3, move the grinding head to the top of the weld, control the movement of the grinding head toward the weld, and control the feed amount of each movement. After each movement, analyze the change in current through the collision detection unit until the current exceeds the threshold, indicating that the grinding head is in contact with the weld, stop feeding, determine the feed amount, and measure the height of the top surface F of the weld.

[0052] S3, determine the single angle grinding strategy;

[0053] First, the working range is re-determined according to the edge position of the weld. Considering that the weld edge is not neat, the measured weld edge position cannot be directly used as the grinding working range, which may result in missing grinding. Therefore, in this embodiment, according to the position of the edges on both sides of the weld, 5 to 10 mm is extended to both sides as the grinding range;

[0054] Secondly, according to the thickness of the weld, set the single grinding thickness of the grinding head, determine the number of reciprocating grindings, and set the automatic grinding equipment to reciprocate to achieve single-angle grinding; because the equipment generally used to grind the rails is small-scale grinding equipment, and the power and rigidity of small-scale grinding equipment are limited, if the weld is thick, a single grinding cannot completely eliminate the weld. In order to ensure the normal operation of the equipment and not cause damage to the equipment, in this embodiment, the determined single grinding thickness does not exceed 2mm, and the integer division method is generally used to set the number of grindings and the thickness of the single grinding. For example, when the weld thickness is detected to be 7.5mm, the grinding thickness is set to 1.5mm and the number of grindings is set to 5 times. When the weld thickness is detected to be 8mm, the grinding thickness is set to 2mm and the number of grindings is set to 4 times.

[0055] Specifically, when setting the grinding strategy, it is necessary to set the automatic grinding equipment to grind at a uniform speed of 15 to 25 mm / s. The specific grinding speed is determined according to the hardness of the material used in the weld. When the material used is harder, the grinding speed is reduced accordingly. When the material used is softer, the grinding speed is increased accordingly.

[0056] Specifically, due to the rigidity of the equipment, the grinding head may be lifted up, that is, the motor shaft reaches the specified position, but the actual grinding head does not reach it, resulting in a bulge on the surface of the rail. Therefore, after completing the single-angle grinding, the grinding effect needs to be evaluated and tested. In this embodiment, when the last reciprocating grinding in step S3 is completed, the grinding power is tested, and the fluctuation range of the grinding power and the fluctuation threshold of the fluctuation time are set. For example, the power threshold is set to 20%, and the fluctuation time threshold is set to 0.2s. If the power fluctuates by more than 20% during the grinding process and the fluctuation time is greater than 0.2S, it is considered that the rail has not been completely ground and the last grinding needs to be repeated until the fluctuation range and fluctuation time of the grinding power are within the fluctuation threshold.

[0057] S4, rotating grinding angle;

[0058] Since the rail surface is composed of multiple arc surfaces, multi-angle reciprocating grinding is required to achieve full coverage of rail grinding requirements. The above steps S2 and S3 can only achieve grinding of one surface. Therefore, after completing the grinding of one surface, it is necessary to rotate the grinding head multiple times to change the angle of the grinding head relative to the rail. After each rotation of the grinding head, the above steps S2 and S3 are repeated to complete the grinding of the corresponding angle. In general, the weld includes three surfaces covered on the rail. Therefore, after completing the grinding of one surface, the angle range of the grinding head rotation is ±90°

[0059] How to set the rotation angle for grinding is also something that needs to be considered when using the device. When the rotation angle is set too large, a large bulge will appear, which will affect the quality of grinding. When the rotation angle is set too small, it will cause a waste of grinding time, thus affecting the efficiency of grinding. Therefore, the setting of the rotation angle needs to find a balance between time and quality:

[0060] In this embodiment, in order to ensure the quality of grinding, when rotating the grinding head angle, the principle of angle selection is: to ensure that the residual height of the welding material between two adjacent grindings does not exceed 0.25mm, refer to Figure 5 As shown, taking the welding material residue of two adjacent grindings as an example, the intersection of the cutting surfaces after the two rotations is set to A, and the midpoint of the arc surface of the rail base material is set to B. It is necessary to ensure that AB is less than 0.25mm. Therefore, according to the actual situation, in this embodiment, the welding material residue height is set to 0.25mm, and the rotation angle is calculated as: starting from 0, ±7°, ±15°, ±30°, ±62°, ±90°. These 11 groups of angles are used as the rotation angles of the grinding head. These 11 groups of angles are used to evenly cover the weld on the surface of the rail; in other embodiments, other rotation angle measurements can also be calculated according to setting other welding material residue heights.

[0061] S5, fine grinding treatment;

[0062] In order to further ensure the smoothness of the track, after completing the above steps S1-S4, a fine grinding process can be performed to ensure that there is no welding slag residue on the track. According to the existing grinding range, it is extended to 250-350mm on both sides of the grinding range, which not only ensures the smoothness of the weld, but also extends to a section of the track on both sides of the weld. The position of the grinding head is re-determined by the collision between the grinding head and the track, and the position of the grinding head is pressed down by 0.02mm as the basis for fine grinding to achieve single-angle fine grinding. For fine grinding, the feed amount of the grinding head is small, and only the burrs on the track need to be processed. Therefore, only one grinding is required, and a grinding speed higher than that in the above step 3 can be set. The grinding speed can be set at a fixed speed of 200mm / s.

[0063] S6, multi-angle fine grinding treatment.

[0064] Similarly, after finishing fine grinding of one angle, it is necessary to perform fine grinding on multiple angles. The grinding head is rotated multiple times to change the angle of the grinding head relative to the track. After each rotation of the grinding head, the above step S5 is repeated to complete fine grinding of the corresponding angle. The angle range of rotation of the grinding head is ±90°. For fine grinding, a corresponding rotation strategy is also provided:

[0065] Start grinding from -90°, grind every 5°, grind every 2° between -10° and 45°, and perform special treatment between -10° and 45°, because when the train runs on the actual track, the contact range between the train wheel and the track is -10° to 45°, therefore, fine grinding is performed every 2° in this interval.

[0066] Example 2

[0067] Reference Figure 6 As shown, in order to complete the grinding method in Example 1, this embodiment also provides an automatic rail grinding device, which at least includes:

[0068] A reciprocating drive unit 1 realizes reciprocating movement in the working area on both sides of the welding seam position;

[0069] The grinding unit 2 is arranged on the reciprocating driving unit 1, and includes a grinding head 21, which is driven by the reciprocating driving unit 1 to detect the position and height of the weld and complete the grinding of the weld;

[0070] The corner unit 3 is arranged on the reciprocating driving unit 1 and connected to the grinding unit 2 to drive the grinding head 21 of the grinding unit 2 to rotate relative to the track.

[0071] Obviously, the above embodiments are merely examples for the purpose of clear explanation and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the present invention.

Claims

1. A layer-by-layer weld grinding method for rail automatic grinding equipment, characterized in that: The following steps are involved: S1. Determine the operating range of the automatic grinding equipment on the track according to the weld position; S2. Use the grinding head to collide with the rail to realize collision detection of various positions of the rail, determine the height of the top surface of the rail base material, the position of the edges on both sides of the weld and the height of the weld vertex, determine the grinding range according to the position of the edges on both sides of the weld, and determine the weld thickness according to the height difference between the weld vertex and the rail base material; including: S2-1, move the grinding head to the rail base material on both sides of the weld respectively, control the movement of the grinding head toward the rail base material, and control the feed amount of each movement. After each movement, analyze whether the grinding head is in contact with the rail base material through the collision detection unit until the grinding head is in contact with the rail base material, stop feeding, determine the feed amount, and measure the height of the top surface of the rail base material; S2-2, maintaining the height of the grinding head in step S2-1, controlling the grinding head to move from both sides of the weld toward the weld, and analyzing whether it is in contact with the edge of the weld through the collision detection unit during the movement, until the grinding head is in contact with the edge of the weld, stopping the movement, and measuring the positions of the edges on both sides of the weld; S2-3, moving the grinding head to the top of the weld, controlling the movement of the grinding head toward the weld, and controlling the feed amount of each movement, and after each movement, analyzing whether the grinding head is in contact with the weld through the collision detection unit, until the grinding head is in contact with the weld, stopping the feed, determining the feed amount, and measuring the height of the top surface of the weld; S3. According to the weld thickness, set the single grinding thickness of the grinding head, determine the number of reciprocating grinding, and set the automatic grinding equipment to reciprocate to achieve single-angle grinding; S4, rotating the grinding head multiple times to change the angle of the grinding head relative to the track, and repeating the above steps S2 and S3 after each rotation of the grinding head to complete the grinding of the angle. The rotation angle range of the grinding head is ±90°.

2. The layer-by-layer weld grinding method of the rail automatic grinding equipment according to claim 1 is characterized in that: In step S2, a grinding range is extended by 5 to 10 mm on both sides according to the positions of the edges of both sides of the weld.

3. The layer-by-layer weld grinding method of the rail automatic grinding equipment according to claim 1 is characterized in that: The single grinding thickness determined in step S3 does not exceed 2 mm.

4. The layer-by-layer weld grinding method of the rail automatic grinding equipment according to claim 1 is characterized in that: In step S3, the automatic grinding equipment is set to grind at a uniform speed of 15 to 25 mm / s.

5. The layer-by-layer weld grinding method of the rail automatic grinding equipment according to claim 1 is characterized in that: When the last reciprocating grinding in step S3 is completed, the grinding power is detected, and a fluctuation threshold of the grinding power fluctuation range and fluctuation time is set. When the grinding power exceeds the threshold, the last grinding is repeated until the grinding power fluctuation range and fluctuation time are within the fluctuation threshold.

6. The layer-by-layer weld grinding method of the rail automatic grinding equipment according to claim 1, characterized in that: In step S4, when the grinding head angle is rotated, the residual height of the welding material between two adjacent grindings does not exceed 0.25 mm.

7. The layer-by-layer weld grinding method of the rail automatic grinding equipment according to claim 1, characterized in that: Also includes: Step S5, fine grinding the rail. According to the existing grinding range, the rail is extended to both sides of the grinding range by 250 to 350 mm. The position of the grinding head is re-determined by the collision between the grinding head and the rail. The position of the grinding head is pressed down by 0.02 mm as the basis for fine grinding, so as to achieve single-angle fine grinding. Step S6, rotating the grinding head multiple times to change the angle of the grinding head relative to the track, repeating the above step S5 after each rotation of the grinding head to complete the fine grinding of the angle, and the rotation angle range of the grinding head is ±90°.

8. The layer-by-layer weld grinding method of the rail automatic grinding equipment according to claim 7, characterized in that: In step S6, grinding is started from -90°, and grinding is performed every 5°, and grinding is performed every 2° between -10° and 45°.

9. An automatic rail grinding device, characterized in that: The method for grinding a weld layer by layer as claimed in any one of claims 1 to 8 above can be implemented, comprising: Reciprocating drive unit, which realizes reciprocating movement in the working area on both sides of the welding position; The grinding unit is arranged on the reciprocating drive unit and includes a grinding head, which is driven by the reciprocating drive unit to detect the position and height of the weld and complete the grinding of the weld; The corner unit is arranged on the reciprocating driving unit and connected with the grinding unit to drive the grinding head of the grinding unit to rotate relative to the track.

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