Peripheral end composite polishing method

Abstract

The invention discloses a peripheral end composite grinding method, belongs to the technical field of steel rail repair treatment, and is used for solving at least one of the problems that in the prior art, turnout grinding efficiency is low, point rail and switch rail grinding is limited, a grinding wheel collides with a fork center and a guard rail in the grinding process, and grinding quality is unstable. The method comprises the steps that a circumferential face grinding device provided with a circumferential face grinding wheel is adopted for grinding a steel rail body and a turnout part; detecting the basic profile of the steel rail by adopting a steel rail profile instrument, and judging whether the angle of the steel rail with the basic profile not reaching the target profile is smaller than the angle coverage range of the peripheral grinding wheel; if yes, an end face grinding device provided with an end face grinding wheel is adopted for supplementing and repairing the profile of the steel rail; if not, a circumferential surface grinding device provided with a circumferential surface grinding wheel is adopted for conducting circumferential surface grinding on the steel rail again; and a peripheral grinding device provided with a paper grinding wheel is adopted to polish and grind the turnout part which is not covered and ground by the peripheral grinding wheel. The device can be used for steel rail polishing.

Description

Technical Field

[0001] This invention belongs to the field of rail repair and treatment technology, and particularly relates to a perimeter composite grinding method. Background Technology

[0002] As railway lines age, rail damage becomes increasingly apparent. Turnouts, being the weakest link in the line, suffer more severe vertical and lateral damage (such as side abrasion, fish-scale patterns, and spalling) due to their structural complexity. Rail grinding, as a crucial method for treating damage, restoring rail profile, and improving wheel-rail relationships, plays an irreplaceable role in the grinding of railway lines and turnouts.

[0003] Currently, turnout grinding is mainly done using turnout grinding cars, supplemented by manual grinding machines. This is because turnout grinding cars grind only one end face (i.e., the side surface of the grinding wheel), and the grinding surfaces of the grinding wheel and rail are relatively small. This results in low grinding efficiency, small grinding surfaces, large grinding restricted areas for turnouts and temperature controllers (the areas of the point rail and switch rail have large grinding restricted areas that traditional turnout grinding cars cannot grind, and can only be supplemented by manual grinding machines), and limited effectiveness in dealing with rail corrugation. At the same time, to avoid the grinding wheel hitting the fork and guard rail during construction, domestic turnout grinding cars generally do not grind the curved sections of the turnout. The curved sections of the turnout are then ground by manual grinding machines for subsequent preventive and repair grinding, but the grinding quality of manual grinding machines is also unstable. Summary of the Invention

[0004] Based on the above analysis, the present invention aims to provide a perimeter composite grinding method to solve at least one of the following problems in the prior art: low grinding efficiency of turnouts, limited grinding of the point rail and switch rail, grinding wheel collision with the fork and guard rail during the grinding process, and unstable grinding quality.

[0005] The objective of this invention is mainly achieved through the following technical solutions.

[0006] This invention provides a peripheral composite polishing method, comprising the following steps: Step 1: Use a circumferential grinding device equipped with a circumferential grinding wheel to grind the main body of the rail and the turnout section to form the basic outline of the main body of the rail and the turnout section; Step 2: Use a rail profiler to detect the basic profile of the rail and determine whether the angle of the rail whose basic profile does not reach the target profile is less than the angle coverage range of the circumferential grinding wheel; If so, an end-face grinding device equipped with an end-face grinding wheel is used to supplement and repair the rail profile to form the target rail profile; If not, the rails will be re-grinded using a peripheral grinding device equipped with a peripheral grinding wheel. Step 3: Use a peripheral grinding device equipped with a paper grinding wheel to polish the turnout parts that the peripheral grinding wheel could not cover.

[0007] Furthermore, the peripheral grinding wheel is a grinding stone wheel, and the end grinding wheel is a grinding stone wheel.

[0008] Furthermore, in step 2, the end face grinding range does not include the turnout sections with a width of less than 20mm for the switch rail, long center rail, and short center rail.

[0009] Furthermore, in step 1, the turnout section includes a long-short-spot rail connection section and a stock rail-spot rail connection section arranged sequentially. The direction from the long-short-center rail connection to the basic rail-point rail connection is clockwise, and the direction from the basic rail-point rail connection to the long-short-center rail connection is counterclockwise.

[0010] Furthermore, in step 1, the grinding methods for the turnout include forward grinding and reverse grinding.

[0011] Furthermore, forward and reverse polishing are performed alternately.

[0012] Furthermore, in step 3, the portion of the turnout that the circumferential grinding wheel fails to cover includes the portion from 100mm to 110mm in front of the switch rail to the 20mm gap between the switch rail and the main rail, as well as the portion from 100mm to 110mm in front of the long and short center rails to the 20mm gap between the long and short center rails.

[0013] Furthermore, in step 3, the polishing is performed at least four times.

[0014] Furthermore, the grinding amount is 0.08mm~0.12mm.

[0015] Furthermore, the operating speeds of the peripheral grinding wheel, end grinding wheel, and paper grinding wheel are all 1km / h to 30km / h.

[0016] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects: A) The peripheral composite grinding method provided by the present invention has significantly improved grinding efficiency, grinding quality and grinding range. It can solve problems such as low grinding efficiency of turnouts, limited grinding of point rails and switch rails, grinding wheel collision with the fork and guard rail during grinding, and unstable grinding quality. It is applicable to the grinding of straight and curved strands of turnouts of various types and can complete the through grinding of the entire turnout.

[0017] B) The circumferential-end composite grinding method provided by this invention, in terms of grinding efficiency, utilizes the combined use of a circumferential grinding device and an end-face grinding device, with circumferential grinding as the primary method and end-face grinding as a secondary method. This allows for flexible switching of grinding modes according to the actual condition of the rail, overcoming the limitations of a single grinding method and greatly improving grinding efficiency. Specifically, the circumferential grinding device can quickly remove damage to the rail surface, forming a basic profile, while the end-face grinding device can perform fine repair on the basic profile, enabling the rail to reach the target profile more quickly.

[0018] C) The peripheral composite grinding method provided by this invention effectively solves the problems of small flat surfaces and unstable grinding quality in existing technologies. The innovative use of grinding stones and paper wheels, along with the combination of peripheral and end-face grinding, results in a smoother rail surface and more precise contours. Especially when dealing with restricted areas such as turnout curved rails, frog rails, and switch rails, it enables more meticulous grinding, improving the overall grinding quality of the turnout.

[0019] D) The peripheral composite grinding method provided by this invention solves the problem of large restricted grinding area in traditional turnout grinding machines in terms of grinding range. The peripheral grinding device equipped with a paper grinding wheel can perform low-speed polishing and grinding on the restricted parts of the turnout that are not covered by the peripheral grinding wheel and the end grinding wheel, ensuring that all parts of the turnout can be effectively ground, and further improving the longitudinal smoothness of the entire turnout.

[0020] E) The perimeter composite grinding method provided by this invention has good adaptability and flexibility. It can flexibly adjust the grinding parameters and grinding methods according to different rail damage conditions and turnout structural characteristics to achieve the best grinding effect. The operation is relatively simple and easy to promote and apply in actual engineering. It can provide strong technical support for the maintenance and repair of railway lines.

[0021] F) The peripheral composite grinding method provided by this invention, employing the aforementioned forward grinding method for turnouts, can reduce the impact of the peripheral grinding wheel on the long center rail, short center rail, switch rail, and stock rail during the grinding process. Simultaneously, it can effectively grind various key parts of the turnout. At the long center rail-short center rail connection, the timing of the peripheral grinding wheel's descent and retraction is rationally controlled, ensuring both grinding effectiveness and preventing collision damage to the short center rail. Similarly, at the switch rail-stock rail connection, precise operation prevents impact on the stock rail, ensuring the safety and effectiveness of the grinding process.

[0022] G) The perimeter-end composite grinding method provided by this invention employs a reverse grinding method, which can also achieve comprehensive and safe grinding of turnouts. The combination of reverse and forward grinding further improves the flexibility and adaptability of turnout grinding. Whether using forward or reverse grinding, the structural characteristics of the turnout and the safety of grinding are fully considered, allowing for the selection of an appropriate grinding direction based on the actual situation of the turnout, thereby better meeting the needs of railway line maintenance and repair.

[0023] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages may become apparent from the description or be learned by practicing the invention. The objects and other advantages of this invention can be realized and obtained from what is particularly pointed out in the description and drawings. Attached Figure Description

[0024] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0025] Figure 1 This is a flowchart of the peripheral composite grinding method provided in Embodiment 1 of the present invention; Figure 2 This is a flowchart of the forward grinding of a turnout in the peripheral composite grinding method provided in Embodiment 1 of the present invention; Figure 3 This is a schematic diagram of the direction of forward grinding of the turnout in the peripheral composite grinding method provided in Embodiment 1 of the present invention; Figure 4 This is a flowchart of the reverse grinding of a turnout in the peripheral composite grinding method provided in Embodiment 1 of the present invention; Figure 5 This is a schematic diagram of the direction of reverse grinding of turnout in the peripheral composite grinding method provided in Embodiment 1 of the present invention.

[0026] Figure label: 1-Point rail; 2-Long center rail; 3-Short center rail; 4-Basic rail. Detailed Implementation

[0027] Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which form part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0028] Example 1 This embodiment provides a peripheral composite polishing method. See [link to relevant documentation]. Figure 1 It includes the following steps: Step 1: Use a circumferential grinding device equipped with a circumferential grinding wheel (the circumferential grinding wheel is a grinding stone wheel) to grind the main body of the rail and the turnout, remove the main damage to the main body of the rail and the turnout, and form the basic outline of the main body of the rail and the turnout. It should be noted that during peripheral grinding, the outer circumferential surface of the peripheral grinding wheel is the grinding working surface. Under the mutual friction between the peripheral grinding wheel and the rail, the peripheral grinding wheel will "self-sharpen" to form an arc-shaped surface similar to the profile of the rail. Step 2: Use a rail profiler to detect the basic profile of the rail and determine whether the angle of the rail whose basic profile does not reach the target profile is less than the angle coverage range of the circumferential grinding wheel. If so, use an end face grinding device equipped with an end face grinding wheel (the end face grinding wheel is a grinding stone wheel) to supplement and repair the rail profile to form the target profile of the rail. If not, the rails will be re-grinded using a peripheral grinding device equipped with a peripheral grinding wheel. Step 3: Use a peripheral grinding device equipped with a paper grinding wheel (a type of flexible grinding wheel) to perform low-speed polishing on the turnout parts that the peripheral grinding wheel could not cover, and perform supplementary grinding on the turnout to further improve the longitudinal smoothness of the entire turnout.

[0029] Compared with the prior art, the perimeter composite grinding method provided in this embodiment has significant improvements in grinding efficiency, grinding quality and grinding range. It can solve problems such as low grinding efficiency of turnouts, limited grinding of the frog rail and switch rail 1, grinding wheel collision with the fork and guard rail during the grinding process, and unstable grinding quality. It is applicable to the grinding of straight and curved strands of turnouts of various types and can complete the through grinding of the entire turnout.

[0030] Specifically, in terms of grinding efficiency, the combined use of the peripheral grinding device and the end grinding device, with peripheral grinding as the primary method and end grinding as a secondary method, allows for flexible switching of grinding modes according to the actual condition of the rail. This overcomes the limitations of a single grinding method and greatly improves grinding efficiency. The peripheral grinding device can quickly remove damage to the rail surface, forming a basic profile, while the end grinding device can perform fine-tuning of the basic profile, enabling the rail to reach the target profile more quickly.

[0031] Regarding grinding quality, the aforementioned perimeter-end composite grinding method effectively solves the problems of small flat surfaces and unstable grinding quality in existing technologies. The innovative application of grinding stones and paper wheels, along with the combination of perimeter and end-face grinding, results in a smoother rail surface and more precise contours. Especially when dealing with restricted areas such as turnout curved rails, frog rails, and switch rails, it enables more meticulous grinding, improving the overall grinding quality of the turnout.

[0032] In terms of grinding range, the aforementioned peripheral composite grinding method solves the problem of large grinding restricted areas in traditional turnout grinding machines. The peripheral grinding device equipped with paper grinding wheels can perform low-speed polishing and grinding on the restricted parts of the turnout that are not covered by the peripheral grinding wheel and the end grinding wheel, ensuring that all parts of the turnout can be effectively ground, and further improving the longitudinal smoothness of the entire turnout.

[0033] In addition, the above-mentioned perimeter composite grinding method has good adaptability and flexibility. It can flexibly adjust the grinding parameters and grinding methods according to different rail damage conditions and turnout structural characteristics to achieve the best grinding effect. The operation is relatively simple and easy to promote and apply in actual engineering projects, providing strong technical support for the maintenance and repair of railway lines.

[0034] To further address the issue of grinding wheels colliding with the fork and guard rails during grinding, step 2 above excludes the turnout sections of switch rail 1, long center rail 2, and short center rail 3 with a width of less than 20mm from the end face grinding area. This is because the turnout sections of switch rail 1, long center rail 2, and short center rail 3 with a width of less than 20mm have a unique and fragile structure, making them prone to collisions when grinding with grinding wheels. Limiting the end face grinding area significantly reduces this risk, ensuring the safety and stability of the grinding operation.

[0035] In step 1 above, for example, the turnout section includes a connecting part of the long point rail 2-short point rail 3 and a connecting part of the main rail 4-point rail 1 arranged in sequence. It should be noted that the width of the main rail 4 remains unchanged.

[0036] The direction from the connection of the long center rail 2 to the short center rail 3 to the connection of the basic rail 4 to the switch rail 1 is defined as forward, and the direction from the connection of the basic rail 4 to the switch rail 1 to the connection of the long center rail 2 to the short center rail 3 is defined as reverse.

[0037] Among them, the side of the connection between the long center rail 2 and the short center rail 3 is the rear, and the side of the connection between the basic rail 4 and the switch rail 1 is the front.

[0038] Accordingly, the grinding methods for turnouts are divided into forward grinding and reverse grinding.

[0039] For the forward grinding method of turnouts, please refer to [link / reference needed]. Figures 2 to 3 It includes the following steps: Step A: At a distance of 50m to 55m from the connection between the long mandrel 2 and the short mandrel 3, the circumferential grinding wheel on the inner side of the rail and the circumferential grinding wheel on the outer side of the rail fall down to grind the circumferential surface of the long mandrel 2. Step B: When grinding until the distance between the long mandrel 2 and the short mandrel 3 is 0mm~20mm (e.g., 15mm~18mm), retract the outer circumferential grinding wheel of the rail to prevent it from impacting the short mandrel 3. At this time, the inner circumferential grinding wheel of the rail is not retracted. Grind the inner circumferential grinding wheel of the rail until the width between the long mandrel 2 and the short mandrel 3 is 20mm, then retract the inner circumferential grinding wheel of the rail. Step C: When the inner and outer circumferential grinding wheels of the rail continue to run to 100mm~110mm in front of the tips of the long center rail 2 and the short center rail 3, the inner and outer circumferential grinding wheels of the rail fall down for grinding. Step D: When the distance between the switch rail 1 and the base rail 4 is 0mm~20mm (e.g., 15mm~18mm), retract the outer circumferential grinding wheel of the rail to prevent it from impacting the base rail 4. At this time, the inner circumferential grinding wheel of the rail is not retracted. Grind the inner circumferential grinding wheel of the rail until the width of the switch rail 1 is 20mm, then retract the inner circumferential grinding wheel of the rail. Step E: When the inner and outer circumferential grinding wheels of the rail continue to run to 100mm~110mm in front of the tip of switch rail 1, the inner and outer circumferential grinding wheels of the rail fall down for grinding. Step F: When grinding to a position 50m or more in front of the tip of switch rail 1, retract the circumferential grinding wheel on the inner side of the rail and the circumferential grinding wheel on the outer side of the rail to complete the forward grinding of the turnout.

[0040] The aforementioned forward grinding method for turnouts reduces the impact of the circumferential grinding wheel on the long point rail 2, short point rail 3, switch rail 1, and stock rail 4 during the grinding process. Simultaneously, it allows for effective grinding of all critical parts of the turnout. At the connection between the long point rail 2 and the short point rail 3, precise control of the timing of the grinding wheel's descent and retraction ensures both effective grinding and prevents collision damage to the short point rail 3. Similarly, precise operation at the connection between the switch rail 1 and the stock rail 4 prevents impact on the stock rail 4, ensuring the safety and effectiveness of the grinding process.

[0041] Correspondingly, for the reverse grinding method of turnouts, see [link to relevant documentation]. Figures 4 to 5 It includes the following steps: Step a: At a position 50m~55m in front of the tip of switch rail 1, the circumferential grinding wheel on the inner side of the rail and the circumferential grinding wheel on the outer side of the rail fall down to grind the circumferential surface of the basic rail 4 in front of the tip of switch rail 1. Step b: When grinding to 100mm~110mm in front of the tip of the rail 1, retract the circumferential grinding wheel on the inner side of the rail and the circumferential grinding wheel on the outer side of the rail; Step c: When the inner and outer circumferential grinding wheels of the rail continue to run to a width of 50mm~55mm for switch rail 1, put down the inner circumferential grinding wheel and continue grinding; Step d: When the distance between the switch rail 1 and the base rail 4 is 0mm~20mm (e.g., 15mm~18mm), lower the circumferential grinding wheel on the outer side of the rail; Step e: Grind to 100mm~110mm in front of the tips of the long mandrel 2 and the short mandrel 3, and then retract the circumferential grinding wheel on the inner side of the rail and the circumferential grinding wheel on the outer side of the rail. Step f: When the inner and outer circumferential grinding wheels of the rail continue to run until the width of the long center rail 2 and the short center rail 3 is 50mm, lower the inner circumferential grinding wheel of the rail for grinding. Step g: When the distance between the long center rail 2 and the short center rail 3 is 0mm~20mm (e.g., 15mm~18mm), lower the circumferential grinding wheel on the outer side of the rail and continue grinding until it is 50m~55m away from the connection part of the long center rail 2 and the short center rail 3. Then, put away the circumferential grinding wheel on the inner side of the rail and the circumferential grinding wheel on the outer side of the rail to complete the reverse grinding of the turnout.

[0042] Reverse grinding can also achieve comprehensive and safe grinding of turnouts. The combination of reverse and forward grinding further improves the flexibility and adaptability of turnout grinding. Both forward and reverse grinding fully consider the structural characteristics of the turnout and the safety of the grinding process, allowing for the selection of the appropriate grinding direction based on the actual conditions of the turnout, thus better meeting the needs of railway line maintenance and repair.

[0043] It should be noted that during the forward and reverse grinding processes, since the main rail 4 does not have special structures like the switch rail 1 and the point rail, the circumferential grinding wheel does not need to be raised and lowered back and forth to continue grinding. All circumferential grinding wheels only need to be retracted at a position more than 50m before the switch rail 1 and after the turnout.

[0044] It should also be noted that the inner circumferential grinding wheel is retracted when grinding to a width of 20mm on the mandrel, and then the grinding wheel is moved in the opposite direction to a width of 50mm on the switch rail 1. The reason for the different grinding positions is that when grinding the variable cross-section areas such as switch rail 1, long mandrel 2, and short mandrel 3, care should be taken to avoid the narrow arc formed by the "self-sharpening" of the grinding wheel during grinding, which can disrupt the profile of the wider area of ​​switch rail 1. Therefore, when grinding the variable cross-section areas such as switch rail 1, long mandrel 2, and short mandrel 3, the circumferential grinding with the grinding wheel should be done along the direction from wide to narrow on switch rail 1, long mandrel 2, and short mandrel 3. If the tip is ground first, it is easy to cause grinding grooves in the wider areas later. Therefore, the starting position for reverse grinding is later.

[0045] In practical applications, forward and reverse grinding are performed alternately. That is, forward grinding is performed first, followed by reverse grinding, and this process is repeated.

[0046] Based on the above forward grinding method and reverse grinding method, correspondingly, in step 3 above, the turnout portion that the peripheral grinding wheel fails to cover includes the portion from 100mm~110mm in front of the tip of switch rail 1 to the 20mm distance between switch rail 1 and main rail 4, and the portion from 100mm~110mm in front of the tips of long center rail 2 and short center rail 3 to the 20mm distance between long center rail 2 and short center rail 3.

[0047] Considering that the turnout grinding is done at low speed, in order to further address the issue of poor grinding results and ensure the grinding effect on the turnout, in step 3 above, the number of grinding passes is more than 4 (e.g., 4-6 passes), and the grinding amount is 0.08mm-0.12mm (e.g., 0.10mm). Supplemental grinding is performed on the restricted areas of the circumferential surface grinding using the grinding wheel, ensuring a smooth transition between the ground and unground areas of the switch rail 1 and the frog rail, completing the continuous grinding of the entire turnout set, and further improving the overall smoothness of the turnout. On the other hand, during the grinding process, it is also necessary to fine-tune the grinding parameters according to the actual condition of the turnout, such as the degree of damage and material characteristics. For example, for areas with more severe damage, the grinding pressure and time should be appropriately increased to ensure effective repair of the damage; while for softer parts, the grinding intensity needs to be reduced to avoid excessive grinding causing new damage.

[0048] To further address the issue of inconsistent grinding quality, for example, in the aforementioned peripheral-end composite grinding method, the operating speeds of the peripheral grinding wheel, end grinding wheel, and paper grinding wheel are all between 1 km / h and 30 km / h. This ensures sufficient contact time and grinding force between the grinding wheel and the rail, resulting in a more stable and uniform grinding process. A suitable operating speed mitigates the problems of insufficient grinding due to excessive speed or over-grinding due to excessive speed. Simultaneously, within this speed range, the grinding wheel can better adapt to different rail damage conditions and turnout structural characteristics, further improving grinding quality.

[0049] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A peripheral composite grinding method, characterized in that, Includes the following steps: Step 1: Use a circumferential grinding device equipped with a circumferential grinding wheel to grind the main body of the rail and the turnout section to form the basic outline of the main body of the rail and the turnout section; Step 2: Use a rail profiler to detect the basic profile of the rail and determine whether the angle of the rail whose basic profile does not reach the target profile is less than the angle coverage range of the circumferential grinding wheel; If so, an end-face grinding device equipped with an end-face grinding wheel is used to supplement and repair the rail profile to form the target rail profile; If not, the rails will be re-grinded using a peripheral grinding device equipped with a peripheral grinding wheel. Step 3: Use a peripheral grinding device equipped with a paper grinding wheel to polish the turnout parts that the peripheral grinding wheel could not cover.

2. The peripheral composite grinding method according to claim 1, characterized in that, In step 2, the end face grinding range does not include the turnout sections where the width of the switch rail, long center rail, and short center rail is less than 20mm.

3. The peripheral composite grinding method according to claim 1, characterized in that, In step 1, the turnout section includes a long-short-spot rail connection section and a stock rail-spot rail connection section arranged sequentially. The direction from the long center rail-short center rail connection section to the basic rail-spot rail connection section is forward, and the direction from the basic rail-spot rail connection section to the long center rail-short center rail connection section is reverse.

4. The peripheral composite grinding method according to claim 3, characterized in that, In step 1, the grinding method for the turnout includes forward grinding and reverse grinding.

5. The peripheral composite grinding method according to claim 4, characterized in that, The forward and reverse grinding processes are performed alternately.

6. The peripheral composite grinding method according to claim 1, characterized in that, In step 3, the portion of the turnout that the circumferential grinding wheel fails to cover includes the portion from 100mm to 110mm in front of the switch rail to the 20mm gap between the switch rail and the main rail, as well as the portion from 100mm to 110mm in front of the long and short center rails to the 20mm gap between the long and short center rails.

7. The peripheral composite grinding method according to claim 1, characterized in that, The peripheral grinding wheel is a grinding stone grinding wheel, and the end grinding wheel is a grinding stone grinding wheel.

8. The peripheral composite grinding method according to claim 1, characterized in that, In step 3, the polishing is performed at least four times.

9. The peripheral composite grinding method according to claim 1, characterized in that, The grinding amount is 0.08mm~0.12mm.

10. The peripheral composite grinding method according to claim 1, characterized in that, The operating speeds of the peripheral grinding wheel, end grinding wheel, and paper grinding wheel are all 1 km / h to 30 km / h.

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