Polishing method for plane soft belt of main bearing ring

Abstract

The invention relates to the technical field of main bearing machining, in particular to a main bearing ring plane soft belt grinding method which comprises the steps that first-time full-area grinding is conducted; and carrying out regional grinding and second-time full-region grinding. According to the method, robot control is combined to complete first-time full-area grinding, regional grinding and second-time full-area grinding, on one hand, protruding hard points on soft and hard junction sites can be quickly and precisely ground and removed, and on the other hand, a soft belt transition area and a soft belt middle area are quickly and precisely ground to the target depth H; and therefore, the problems of long time consumption, low productivity and low precision of manual polishing in the prior art are solved. In addition, the robot is adopted to control grinding, and the problem that dust generated by manual grinding harms health is solved.

Description

Technical Field

[0001] This invention relates to the field of main bearing processing technology, and specifically to a method for grinding the flat soft strip of main bearing raceways. Background Technology

[0002] During the quenching process of the raceway of the main bearing in a tunneling machine, a quenching blind zone appears at the connection between its beginning and end. This blind zone has lower hardness and is also called the soft strip. The hardness of the raceway after normal quenching is generally 58~62HRC, while the hardness of the soft strip area is generally around 35HRC. Therefore, the soft strip is the weakest area of ​​the main bearing raceway. When the main bearing is working normally, the bearing rollers generate a large force as they roll in the raceway. The soft strip has a weak ability to resist alternating rolling loads. Under long-term alternating loads, the soft strip area will fail first. Therefore, it is necessary to grind the soft strip area of ​​the main bearing. After grinding, the soft strip area of ​​the main bearing is fitted with a clearance fit to prevent the bearing rollers from contacting and bearing force in this area.

[0003] Considering the presence of a hard-soft boundary in the soft belt area of ​​the main bearing, when this boundary reaches the required grinding depth, the grinding depth of other areas of the soft belt may have already exceeded the maximum set grinding depth. Ensuring that the grinding depth at the hard-soft boundary is consistent with the set grinding depth in the soft belt area is a key challenge in soft belt grinding. Currently, manual grinding is still the primary method for grinding bearing raceway soft belts. The grinding depth of raceway soft belts is generally 0.2~0.5mm. When manually grinding with a handheld grinder, it is difficult to accurately control the grinding depth and surface roughness. Furthermore, manual grinding suffers from high labor intensity, low efficiency, low safety, poor protection, and poor product consistency, making it difficult to guarantee the grinding quality of soft belts. This is especially true for grinding larger main bearing raceway soft belts, which is time-consuming and severely restricts production capacity. Moreover, the dust generated during the grinding process affects human health.

[0004] In summary, there is a need to develop a method for grinding the flat soft belt of the main bearing ring to solve the problems of long time consumption, low production capacity, low precision and dust hazards in the existing manual grinding technology. Summary of the Invention

[0005] The purpose of this invention is to provide a method for grinding the flat soft strip of a main bearing raceway, the specific technical solution of which is as follows: A method for grinding the flat soft strip of a main bearing raceway, used to grind the flat soft strip area at the axial end of the raceway of a main bearing raceway, comprising: Step S1: First full-area sanding; First, the planar soft strip area is divided into a soft strip middle area and a soft strip transition area; there are two soft strip transition areas, located at both ends of the soft strip middle area; the hardness of the soft strip transition area is greater than that of the soft strip middle area; the midpoint of the soft strip middle area is marked with a grinding point M4. Secondly, the first grinding piece is controlled by a robot to reciprocate through the entire planar soft strip area from grinding point M4 to perform the first full-area grinding; when the grinding depth in the middle area of ​​the soft strip is 0.7 to 0.9 times the target depth H, the grinding is stopped. Step S2: Polishing by area; First, after the first full-area polishing, the irregular curve positions appearing on both sides of polishing point M4 in the middle region of the soft strip, i.e., the soft-hard junction points, are marked as polishing points M3 and M5, respectively; the two ends of one of the soft strip transition regions in the length direction are marked as polishing points M1 and M2, respectively; the two ends of the other soft strip transition region in the length direction are marked as polishing points M6 and M7, respectively; wherein, polishing points M1 to M7 are marked sequentially along the length direction of the planar soft strip region; the area between polishing points M2 and M6 is the middle region of the soft strip; Secondly, segmented grinding is performed between grinding points M1 and M3 and between grinding points M7 and M5. Step S3: Second full-area polishing; A robot is used to control the first grinding component to reciprocate and grind the entire planar soft strip area for a second full-area grinding. When the grinding depth of the middle area of ​​the soft strip reaches the target depth H, the grinding is stopped.

[0006] Optionally, when using segmented grinding between grinding points M1 and M3, the robot first controls the first grinding part to grind from grinding point M1 to grinding point M3, grinding back and forth. When the protruding hard point at grinding point M3 is ground flat, the grinding area is gradually shortened from grinding point M3 to grinding point M2. When the grinding depth between grinding points M1 and M2 is the target depth H, grinding is stopped.

[0007] Optionally, when using segmented grinding between grinding point M7 and grinding point M5, the robot first controls the first grinding part to grind from grinding point M7 to grinding point M5, grinding back and forth. When the protruding hard point at grinding point M5 is ground flat, the grinding area is gradually shortened from grinding point M5 to grinding point M6. When the grinding depth between grinding point M7 and grinding point M6 is the target depth H, grinding is stopped.

[0008] Optionally, the grinding area is shortened by 4-8 mm each time from grinding point M3 to grinding point M2; and the grinding area is shortened by 4-8 mm each time from grinding point M5 to grinding point M6.

[0009] Optionally, in the segmented grinding process, the electric spindle of the first grinding element has a rotational speed of 4000-6000 r / min, a feed rate of 5-15 mm / s, and a grinding depth of 0.02-0.05 mm / cycle.

[0010] Optionally, in the first full-area grinding, the electric spindle speed of the first grinding workpiece is 4000-6000 r / min, the feed rate is 5-15 mm / s, and the grinding amount is 0.02-0.05 mm / cycle.

[0011] Optionally, in the second full-area grinding, the electric spindle speed of the first grinding element is 4000-6000 r / min, the feed rate is 20-50 mm / s, and the grinding amount is 0.01-0.03 mm / time.

[0012] Optionally, the target depth H is 0.3~0.4 mm.

[0013] Optionally, the method for grinding the flat soft strip of the main bearing ring further includes post-processing; the post-processing includes sequentially using a robot-controlled second grinding piece and a third grinding piece to grind the entire flat soft strip area.

[0014] Optionally, the electric spindle speed of the second grinding element is 4000-6000 r / min, the feed rate is 10-30 mm / s, and the grinding amount is 0.005-0.01 mm / stroke; the electric spindle speed of the third grinding element is 4000-6000 r / min, the feed rate is 10-30 mm / s, and the grinding amount is 0.001-0.002 mm.

[0015] The application of the technical solution of the present invention has at least the following beneficial effects: This invention provides a method for grinding a planar soft strip on a main bearing raceway. First, the planar soft strip area is divided into a middle soft strip area and a transition soft strip area. The hardness of the transition soft strip area is greater than that of the middle soft strip area. Furthermore, the hardness of grinding points M3 and M5 on either side of grinding point M4 in the middle soft strip area is greater than that of grinding point M4. Second, based on the difference in hardness distribution, a combination of robot-controlled grinding is used to complete the first full-area grinding, the segmented grinding, and the second full-area grinding. This method enables rapid and high-precision grinding to remove protruding hard points at the soft-hard interface, and also allows the transition soft strip area and the middle soft strip area to be rapidly and precisely ground to the target depth H. This solves the problems of long processing time, low productivity, and low precision associated with manual grinding in existing technologies. Additionally, using robot-controlled grinding eliminates the health hazard caused by dust generated during manual grinding.

[0016] In addition to the objectives, features, and advantages described above, the present invention has other objectives, features, and advantages. The invention will now be described in further detail with reference to the figures. Attached Figure Description

[0017] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a schematic diagram of the structure of the main bearing ring in an embodiment of the present invention. Figure 2 This is a schematic diagram of the structure after the grinding site markings are made in the planar soft strip region according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the axial structure of the planar soft strip area after grinding in an embodiment of the present invention; Among them, 100 is the main bearing ring, L is the planar soft belt area, A is the middle area of ​​the soft belt, and B is the transition area of ​​the soft belt. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention are within the scope of protection of the present invention.

[0019] Example: See Figures 1-3 A method for grinding a flat soft strip on a main bearing raceway, used to grind a flat soft strip region L (80mm in length) at the axial end of the raceway 100 of a main bearing raceway, comprising: Step S1: First full-area sanding; First, the planar flexible strip region L is divided into a middle flexible strip region A (50mm in length) and a transition flexible strip region B (each transition flexible strip region B is 15mm in length). There are two transition flexible strip regions B, located at opposite ends of the middle flexible strip region A. The hardness of the transition flexible strip region B is greater than that of the middle flexible strip region A. The midpoint of the middle flexible strip region A is marked as a grinding point M4. Second, a robot-controlled first grinding tool (specifically a diamond grinding wheel made of electroplated CBN) is used to perform the first full-area grinding by reciprocating through the entire planar flexible strip region L starting from the grinding point M4. Starting the grinding from the grinding point M4 facilitates the robot's accurate and rapid confirmation of the grinding point and also facilitates tool setting. When the grinding depth of the middle flexible strip region A reaches 0.7 to 0.9 times the target depth H, the grinding is stopped.

[0020] Step S2: Polishing by area; First, after the first full-area polishing, the irregular curve positions appearing on both sides of polishing point M4 in the middle region A of the soft strip, i.e., the soft-hard junction points, are marked as polishing point M3 and polishing point M5, respectively. The hardness of polishing points M3 and M5 on both sides of polishing point M4 in the middle region A of the soft strip is greater than the hardness of polishing point M4. The two ends of one of the soft strip transition regions B in the length direction are marked as polishing point M1 and polishing point M2, respectively. The two ends of the other soft strip transition region B in the length direction are marked as polishing point M6 and polishing point M7, respectively. Among them, polishing point M1 to polishing point M7 are marked sequentially along the length direction of the planar soft strip region L. The area between polishing point M2 and polishing point M6 is the middle region A of the soft strip.

[0021] Secondly, segmented grinding is performed between grinding points M1 and M3 and between grinding points M7 and M5. Specifically, when using segmented grinding between grinding points M1 and M3, the robot first controls the first grinding piece to grind from grinding point M1 to grinding point M3, reciprocating approximately twice. Once the protruding hard spot at grinding point M3 is smoothed out, the grinding area is gradually shortened from grinding point M3 towards grinding point M2. Grinding stops when the measured grinding depth between grinding points M1 and M2 reaches the target depth H. Each time the grinding area is shortened from grinding point M3 to grinding point M2 by 5mm, the grinding operation is completed steadily and efficiently, removing any hard spots appearing from grinding point M3 to grinding point M2. After each shortening of the grinding area, the shortened area is ground approximately twice.

[0022] When using segmented grinding between grinding points M7 and M5, the robot first controls the first grinding piece to grind from grinding point M7 to grinding point M5, repeating the grinding motion approximately twice. Once the protruding hard spot at grinding point M5 is smoothed out, the grinding area is gradually shortened from grinding point M5 to grinding point M6. Grinding stops when the measured grinding depth between grinding points M7 and M6 reaches the target depth H. Specifically, the grinding area is shortened by 5mm each time from grinding point M5 to grinding point M6 to ensure a steady and efficient grinding operation, removing any hard spots appearing from grinding point M5 to grinding point M6. After each shortening of the grinding area, the shortened area is ground approximately twice.

[0023] Step S3: Second full-area polishing; The robot controls the first grinding piece to reciprocate through the entire planar soft strip area L for a second full-area grinding. Specifically, the grinding path used in the second full-area grinding is from M1 to M7, and then from M7 to M1, in a reciprocating cycle (approximately 1-2 reciprocating grinding cycles). When the grinding depth of the middle area A of the soft strip is measured to be the target depth H, the grinding is stopped.

[0024] In the segmented grinding process, the electric spindle of the first grinding component has a rotational speed of 6000 r / min, a feed rate of 10 mm / s, and a grinding depth of 0.03 m / cycle.

[0025] In the first full-area grinding, the electric spindle speed of the first grinding workpiece is 6000 r / min, the feed rate is 10 mm / s, and the grinding depth is 0.03 mm / cycle. The grinding path used in the first full-area grinding is to grind from M4 to M1, then from M1 to M7, and then from M7 to M1 in a reciprocating cycle (approximately 5 reciprocating grinding cycles).

[0026] In the second full-area grinding, the electric spindle of the first grinding workpiece has a rotation speed of 6000 r / min, a feed rate of 30 mm / s, and a grinding depth of 0.01 mm / cycle.

[0027] The middle area of ​​the soft strip is ground to a target depth H of 0.4 mm, and the transition area of ​​the soft strip is ground to a target depth H of 0.3 mm.

[0028] The method for polishing the planar soft strip of the main bearing ring also includes post-processing. The post-processing involves sequentially using a robot-controlled second polishing component (specifically a flap wheel made of sandpaper) and a third polishing component (specifically a polishing wheel made of fiber) to polish the entire planar soft strip area L. Specifically, the second polishing component polishes twice along the direction from M1 to M7 to improve the roughness of the planar soft strip area L. The flap wheel is formed by multiple pieces of sandpaper arranged in the same direction. Polishing against the direction of the sandpaper arrangement may cause the sandpaper to fray, resulting in poor polishing. Therefore, polishing must be done along the direction of the sandpaper arrangement. Thus, in this embodiment, the polishing path of the flap wheel is along the direction of the sandpaper arrangement, i.e., from M1 to M7. The third polishing component polishes once along the direction from M1 to M7 to remove minute impurities from the planar soft strip area L, improving its smoothness and brightness.

[0029] The electric spindle using the second grinding element has a rotational speed of 5000 r / min, a feed rate of 20 mm / s, and a grinding depth of 0.005 mm / cycle; the electric spindle using the third grinding element has a rotational speed of 4000 r / min, a feed rate of 30 mm / s, and a grinding depth of 0.001 mm.

[0030] In this embodiment, based on the differences in hardness distribution, a combination of robot-controlled processes is used to complete the first full-area grinding, segmented grinding, and a second full-area grinding. This allows for rapid and high-precision grinding to remove protruding hard points at the soft-hard interface, and also enables the soft band transition area B and the soft band middle area A to be rapidly and precisely ground to the target depth H. This solves the problems of long processing time, low productivity, and low precision associated with manual grinding in existing technologies. Furthermore, using robot-controlled grinding eliminates the health hazard caused by dust generated during manual grinding.

[0031] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method of grinding a main bearing raceway flat soft band for grinding a flat soft band area of an axial end portion of a main bearing raceway, characterized by, The method comprises the following steps: Step S1, first full-area polishing; Firstly, the flat soft belt area is divided into a soft belt middle area and soft belt transition areas; the soft belt transition areas are two and are respectively located on two ends of the soft belt middle area; the hardness of the soft belt transition areas is greater than that of the soft belt middle area; a middle point of the soft belt middle area is marked as a polishing point M4; Secondly, a first polishing element is controlled by a robot to reciprocatingly polish the whole flat soft belt area from the polishing point M4 to perform first full-area polishing; when the polishing depth of the soft belt middle area is 0.7-0.9 times of the target depth H, the polishing is stopped; Step S2, area-by-area polishing; Firstly, after the first full-area polishing, irregular curve positions, i.e. soft-hard junction points, appearing on both sides of the polishing point M4 in the soft belt middle area are respectively marked as polishing points M3 and M5; two ends of one of the soft belt transition areas in the length direction are respectively marked as polishing points M1 and M2; two ends of the other soft belt transition area in the length direction are respectively marked as polishing points M6 and M7; the polishing points M1-M7 are sequentially marked along the length direction of the flat soft belt area; the area between the polishing points M2 and M6 is the soft belt middle area; Secondly, area-by-area polishing is respectively performed between the polishing points M1 and M3 and between the polishing points M7 and M5; Step S3, second full-area polishing; The first polishing element is controlled by the robot to reciprocatingly polish the whole flat soft belt area to perform second full-area polishing; when the polishing depth of the soft belt middle area is the target depth H, the polishing is stopped.

2. The main bearing raceway flat belt grinding method of claim 1, wherein, When the area-by-area polishing is performed between the polishing points M1 and M3, the first polishing element is controlled by the robot to polish from the polishing point M1 to the polishing point M3, and the polishing is reciprocated; when the convex hard points at the polishing point M3 are ground, the polishing area is gradually shortened from the polishing point M3 to the polishing point M2; when the polishing depth between the polishing points M1 and M2 is the target depth H, the polishing is stopped.

3. The main bearing raceway flat belt grinding method of claim 2, wherein, When the area-by-area polishing is performed between the polishing points M7 and M5, the first polishing element is controlled by the robot to polish from the polishing point M7 to the polishing point M5, and the polishing is reciprocated; when the convex hard points at the polishing point M5 are ground, the polishing area is gradually shortened from the polishing point M5 to the polishing point M6; when the polishing depth between the polishing points M7 and M6 is the target depth H, the polishing is stopped.

4. The main bearing raceway flat belt grinding method of claim 3, wherein, The polishing area is shortened by 4-8 mm each time from the polishing point M3 to the polishing point M2; the polishing area is shortened by 4-8 mm each time from the polishing point M5 to the polishing point M6.

5. The main bearing raceway flat belt grinding method of claim 3, wherein, In the area-by-area polishing, the rotational speed of the electric spindle of the first polishing element is 4000-6000 r / min, the feed speed is 5-15 mm / s, and the grinding amount is 0.02-0.05 mm / time.

6. The main bearing raceway flat belt grinding method of claim 1 wherein, In the first time full area polishing, the electric spindle speed of the first polishing piece is 4000-6000r / min, the feed speed is 5~15mm / s, and the grinding amount is 0.02~0.05mm / time.

7. The main bearing raceway flat belt grinding method of claim 1 wherein, In the second time full area polishing, the electric spindle speed of the first polishing piece is 4000-6000r / min, the feed speed is 20~50mm / s, and the grinding amount is 0.01~0.03mm / time.

8. The main bearing raceway flat belt grinding method of claim 1 wherein, The target depth H is 0.3~0.4mm.

9. The main bearing raceway flat belt grinding method of any of claims 1-8, wherein, Further comprising post-processing; the post-processing comprises polishing the entire flat soft belt area by using the second polishing piece and the third polishing piece in turn under the control of the robot.

10. The main bearing raceway flat belt grinding method of claim 9, wherein, The electric spindle speed of the second polishing piece is 4000-6000r / min, the feed speed is 10~30mm / s, and the grinding amount is 0.005~0.01mm / time; the electric spindle speed of the third polishing piece is 4000-6000r / min, the feed speed is 10~30mm / s, and the grinding amount is 0.001~0.002mm.

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