Milling drum for road milling machines

Abstract

The present invention discloses a milling drum for a road milling machine, comprising a milling drum base and N milling picks, wherein the milling drum base has a middle section area including the location of a throwing plate and two side areas adjacent to the middle section area, and the milling picks include high-wear resistant picks and high-toughness picks, wherein the high-toughness picks are distributed in the middle section area of ​​the milling drum base, and the high-wear resistant picks are distributed in the two side areas of the milling drum base. The present invention can adjust and arrange the milling picks according to different construction road conditions, is simple to operate, and has strong practicality, can greatly improve the comprehensive utilization rate of the milling picks, reduce the replacement frequency of the milling picks, and save the road milling cost.

Description

Technical Field

[0001] The invention relates to the technical field of road milling equipment, in particular to a milling drum used for a road milling machine. Background Art

[0002] With the rapid development of expressways in my country, the maintenance requirements for high-grade asphalt pavements are getting higher and higher. New asphalt pavements need to be renovated on a large scale after 10 to 15 years of use, that is, the old pavement is milled and removed by a milling machine, and then renovated and repaired. Therefore, milling construction of asphalt pavements will become the mainstream construction method.

[0003] The main equipment for road milling is the milling machine. The milling drum at the bottom of the milling machine is the key component for directly milling the road surface, and the milling pick on the milling drum is the core component for directly crushing the road surface material.

[0004] The existing milling drum consists of a milling drum base and a milling pick, and the milling pick is installed on the milling drum base. The following phenomena often occur during the road milling process, resulting in low milling efficiency and high cost:

[0005] 1) When shallowly milling pure asphalt surface, the wear resistance and impact resistance of the milling pick do not match the working conditions, resulting in a reduction in the service life of the milling pick, or an increase in milling resistance and reduced efficiency.

[0006] 2) When milling a composite road surface of asphalt surface layer and water-stabilizing layer, the wear resistance and impact resistance of the milling pick cannot meet the requirements, resulting in abnormal failure due to broken teeth and increased costs.

[0007] 3) When milling complex roads with full water-stable layers, the wear resistance and impact resistance of the milling picks do not meet the requirements, and the tooth body is prone to wear too quickly, causing the main alloy to fall off, or the main alloy to break, and other abnormal failures. Costs increase.

[0008] 4) During the material throwing process, the milling pick teeth in the middle section of the milling drum near the throwing plate are exposed to more wear and erosion, resulting in abnormal failure of the tooth body. Summary of the invention

[0009] In order to solve the above problems existing in the prior art, the present invention provides a milling drum which can improve efficiency and reduce cost.

[0010] The present invention is used for a milling drum of a road milling machine, comprising a milling drum base and N milling picks, and is characterized in that the milling drum base has a middle section area including a throwing plate and two side areas adjacent to the middle section area, and the milling picks include high-wear resistant picks and high-toughness picks, the high-toughness picks are distributed in the middle section area of ​​the milling drum base, and the high-wear resistant picks are distributed in the two side areas of the milling drum base.

[0011] When the milling drum is used for shallow milling of asphalt surface layer, the N milling picks include 70% to 90% × N high wear-resistant picks and 30% to 10% × N high toughness milling picks;

[0012] When the milling drum is used for milling the composite road surface of the asphalt surface layer and the water-stabilizing layer, the N milling picks include 30% to 70% × N high-wear-resistant picks and 30% to 70% × N high-toughness milling picks;

[0013] When the milling drum is used for milling a complex road surface with a full water-stable layer, the N milling picks include 10% to 30% × N high-wear-resistant picks and 70% to 90% × N high-toughness milling picks.

[0014] The milling pick comprises a main alloy part and a tooth body, wherein the main alloy part is welded to the top of the tooth body by brazing, the tooth body has a shank, a tooth seat is provided on a milling drum base, and the tooth body is connected to the milling drum base through the tooth seat.

[0015] The wear-resistant pick tooth body (32) is provided with a groove for reducing the resistance of the milling drum when it is working and improving the working efficiency.

[0016] The main alloy part of the high wear-resistant pick is made of hard alloy, with a cobalt content of 5.5% to 6% and a hardness of 88 to 89 HRA.

[0017] The main alloy part of the high-toughness pick is made of hard alloy, with a cobalt content of 6% to 6.5% and a hardness of 87 to 88.5 HRA.

[0018] The milling drum of the present invention divides the milling drum base into a middle section area and two side areas, wherein the middle section area contains the position of the throwing plate, high-toughness milling picks are arranged in the middle section area, and high-wear-resistant picks are arranged in the two side areas. Since the middle section area has the throwing plate, the milling picks at this position will be subjected to a strong impact during the throwing process, while the milling picks at the positions of the two side areas are subjected to relatively weak impact. Therefore, the present invention can adjust and arrange the milling picks according to different construction road conditions, is simple to operate, and has strong practicality. It can greatly improve the comprehensive utilization rate of the milling picks, reduce the replacement frequency of the milling picks, and save the cost of road milling.

[0019] Other features and advantages of the present invention will become more apparent with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A schematic structural diagram of a milling drum of the present invention is exemplarily shown;

[0021] Figure 2 A schematic structural diagram of a highly wear-resistant milling pick of the present invention is exemplarily shown;

[0022] Figure 3 A schematic structural diagram of a high-toughness milling pick of the present invention is exemplarily shown;

[0023] Figure 4 A structural schematic diagram of the main alloy of the milling pick of the present invention is shown exemplarily.

[0024] Reference numerals: milling drum base 1, milling middle section area 11, two side areas 12;

[0025] Throwing plate 2;

[0026] The milling pick 3, the main alloy 31, and the tooth body 32, the main alloy 31 is welded to the top of the tooth body 32 by brazing, and the shank of the tooth body 32 is connected to the surface of the milling drum base 1 through the tooth seat 4 on the surface of the milling drum. DETAILED DESCRIPTION

[0027] Some embodiments of the present invention are described below in conjunction with the accompanying drawings, but not all embodiments. For those skilled in the art, all other embodiments obtained without creative work are within the scope of protection of the present invention.

[0028] The inventor designed a milling drum on which two types of milling picks are installed, a total of N pieces, one is a high-wear-resistant milling pick, and the other is a high-toughness milling pick. The two types of milling picks are distributed according to different proportions according to different working conditions, wherein the high-toughness milling pick is arranged in the middle section of the milling drum base to form a high-toughness milling pick area, and high-wear-resistant milling picks are arranged on both sides of the area to form a high-wear-resistant milling pick area. The main alloy material of the high-wear-resistant pick is cemented carbide, the cobalt content is 5.5% to 6%, and the hardness is 88 to 89HRA. The main alloy material of the high-toughness pick is cemented carbide, the cobalt content is 6% to 6.5%, and the hardness is 87 to 88.5HRA. By combining and reasonably distributing high-wear-resistant milling picks with high-toughness milling picks, the comprehensive utilization rate of milling picks is effectively improved, the replacement frequency of milling picks is reduced, the milling efficiency is improved, and the milling cost is reduced.

[0029] The milling drum provided by the present invention will be described in detail below in conjunction with the accompanying drawings.

[0030] Figure 1 A schematic diagram of the structure of the milling drum of the present invention is shown, referring to Figure 1 As shown, the milling drum has a length of L and a diameter of D, and includes a milling drum base 1 and a throwing plate 2. The milling picks 3 are arranged along the surface of the milling drum base 1 according to a set spiral trajectory, and N is a natural number greater than 10;

[0031] Specifically, the milling drum base 1 includes a milling middle section area 11 and two side areas 12, wherein the middle section area 11 contains a throwing plate 2, and the throwing plate 2 is mainly used to throw the milled material smoothly onto the conveyor belt of the milling machine. Therefore, the milling picks near the throwing plate 2 are inevitably subjected to strong impacts of the material, and high-toughness milling picks are set in the middle section area 11 to withstand the relatively large impact force during the working process; the two side areas 12 are basically not impacted by the material of the throwing plate 2, and the use of high-wear-resistant milling picks in the two side areas is sufficient to meet its working needs. In actual applications, the length of the middle section area and the two side areas of the milling drum is not fixed, but is specifically divided according to specific working conditions.

[0032] The milling pick 3 includes a main alloy 31 and a tooth body 32. The main alloy 31 is welded to the top of the tooth body 32 by brazing. The shank of the tooth body 32 is connected to the surface of the milling drum base 1 through a tooth seat 4 on the surface of the milling drum. Figure 1 shown.

[0033] Figure 2 A structure of a milling pick is shown. A groove 321 is provided on the tooth body 32 to reduce the scouring resistance of the broken road material on the tooth body during the milling process and improve the milling efficiency. The milling pick structure is suitable for high wear resistance milling picks and is mainly used for asphalt layer milling under relatively simple working conditions.

[0034] Figure 3 Another structure of the milling pick is shown. No groove is set on the tooth body 32 to increase the strength of the tooth head. This is mainly for the relatively complex milling process where a large amount of road crushing materials will wash the tooth body and cause greater wear on the tooth body. This milling pick structure is used for high-toughness milling picks.

[0035] Figure 4 The structure of the main alloy 31 at the tip of the milling pick 3 is shown. The maximum height of the main alloy is 16mm-20.5mm, the maximum diameter is 16mm-20.5mm, and the material is a hard alloy with a cobalt content of 5.5% to 6.5% and a hardness of 87-89HRA. The size and material of the main alloy are adjusted according to different milling conditions.

[0036] Example 1

[0037] The length L of the milling drum is 1000mm, and the diameter D is 660mm. 84 milling picks (i.e., N=84) are installed on the milling drum, which is used for shallow milling of a large area of ​​asphalt surface. The 84 milling picks include 75 high wear-resistant milling picks and 9 high toughness picks. The main alloy height of the high wear-resistant milling pick is 16.0mm, the maximum diameter is 16mm, the main alloy material is 6% cobalt, and the hardness is 88.5HRA. The main alloy height of the high toughness milling pick is 16.0mm, the maximum diameter is 17.5mm, the main alloy material is 6% cobalt, and the hardness is 88HRA.

[0038] Example 2

[0039] The length L of the milling drum is 1000 mm, the diameter D is 980 mm, and 102 milling picks (i.e., N=102) are installed on the milling drum, which is used for shallow milling of a larger area of ​​pure asphalt surface layer. The 102 milling picks 2 include 82 high wear-resistant milling picks and 20 high toughness picks. The main alloy height of the high wear-resistant milling pick is 16.0 mm, the maximum diameter is 17.5 mm, the main alloy material is 6% cobalt content, and the hardness is 88.5 HRA. The main alloy height of the high toughness milling pick is 17.5 mm, the maximum diameter is 17.5 mm, the main alloy material is 6% cobalt content, and the hardness is 88 HRA.

[0040] Example 3

[0041] The length L of the milling drum is 1200 mm, the diameter D is 720 mm, and 114 milling picks (i.e., N=114) are installed on the milling drum, which is used for shallow milling of a larger area of ​​pure asphalt surface layer. The 114 milling picks 2 include 80 high wear-resistant milling picks and 34 high toughness picks. The main alloy height of the high wear-resistant milling pick is 16.0 mm, the maximum diameter is 17.5 mm, the main alloy material is 6% cobalt content, and the hardness is 88.5 HRA. The main alloy height of the high toughness milling pick is 17.5 mm, the maximum diameter is 17.5 mm, the main alloy material is 6% cobalt content, and the hardness is 88 HRA.

[0042] Example 4

[0043] The length L of the milling drum is 1200 mm, the diameter D is 720 mm, and 114 milling picks (i.e., N=114) are installed on the milling drum, which is used for large-area, long-distance milling of asphalt surface layer and water-stabilizing layer composite road surface. The 114 milling picks 2 include 76 high-wear-resistant milling picks and 38 high-toughness picks. The main alloy height of the high-wear-resistant milling pick is 16.0 mm, the maximum diameter is 17.5 mm, the main alloy material is 6% cobalt content, and the hardness is 88.5 HRA. The main alloy height of the high-toughness milling pick is 17.5 mm, the maximum diameter is 17.5 mm, the main alloy material is 6% cobalt content, and the hardness is 88 HRA.

[0044] Example 5

[0045] The length L of the milling drum is 2000 mm, the diameter D is 980 mm, and 168 milling picks (i.e., N=168) are installed on the milling drum, which is used for large-area, long-distance milling of asphalt surface layer and water-stabilizing layer composite road surface. The 168 milling picks 2 include 92 high-wear-resistant milling picks and 76 high-toughness picks. The main alloy height of the high-wear-resistant milling pick is 17.5 mm, the maximum diameter is 19.0 mm, the main alloy material is 6% cobalt content, and the hardness is 88.5 HRA. The main alloy height of the high-toughness milling pick is 19.0 mm, the maximum diameter is 19.5 mm, the main alloy material is 6% cobalt content, and the hardness is 88 HRA.

[0046] Example 6

[0047] The length L of the milling drum is 2000 mm, the diameter D is 980 mm, and 168 milling picks (i.e., N=168) are installed on the milling drum, which is used for large-area, long-distance asphalt surface layer and water-stabilizing layer composite road milling. The 168 milling picks 2 include 52 high-wear-resistant milling picks and 116 high-toughness picks. The main alloy height of the high-wear-resistant milling pick is 17.5 mm, the maximum diameter is 19.0 mm, the main alloy material is 6% cobalt content, and the hardness is 88HRA. The main alloy height of the high-toughness milling pick is 19.0 mm, the maximum diameter is 19.5 mm, the main alloy material is 6.5% cobalt content, and the hardness is 87.5HRA.

[0048] Example 7

[0049] The length L of the milling drum is 2000 mm, the diameter D is 980 mm, and 168 milling picks (i.e., N=168) are installed on the milling drum. When the long-distance full-water stable layer complex road surface is milled, the 168 milling picks 2 include 42 high-wear-resistant milling picks and 126 high-toughness picks. The main alloy height of the high-wear-resistant milling pick is 19.0 mm, the maximum diameter is 19.5 mm, the main alloy material is 6% cobalt, and the hardness is 88HRA. The main alloy height of the high-toughness milling pick is 21.0 mm, the maximum diameter is 20.5 mm, the main alloy material is 6.5% cobalt, and the hardness is 87.5HRA.

[0050] Example 8

[0051] The length L of the milling drum is 2200 mm, the diameter D is 1070 mm, and 184 milling picks (i.e., N=184) are installed on the milling drum. When the long-distance full-water stable layer complex road surface is milled, the 184 milling picks 2 include 38 high-wear-resistant milling picks and 146 high-toughness picks. The main alloy height of the high-wear-resistant milling pick is 20.5 mm, the maximum diameter is 20.5 mm, the main alloy material is 6% cobalt, and the hardness is 88HRA. The main alloy height of the high-toughness milling pick is 21.0 mm, the maximum diameter is 22 mm, the main alloy material is 6.5% cobalt, and the hardness is 87HRA.

[0052] Example 9

[0053] The length L of the milling drum is 2200 mm, the diameter D is 1070 mm, and 184 milling picks (i.e., N=184) are installed on the milling drum. When long-distance full-water stable layer complex road milling is applied, the 184 milling picks 2 include 20 high wear-resistant milling picks and 164 high toughness picks. The main alloy height of the high wear-resistant milling pick is 20.5 mm, the maximum diameter is 20.5 mm, the main alloy material is 6% cobalt content, and the hardness is 87.5HRA. The main alloy height of the high toughness milling pick is 21.0 mm, the maximum diameter is 22 mm, the main alloy material is 6.5% cobalt content, and the hardness is 87HRA.

[0054] The result obtained through the above embodiments is that compared with the traditional single-model milling pick milling drum, under the same working conditions and the same milling amount, the milling pick replacement rate of the milling drum of the present invention can be reduced by 30%-50%, which not only reduces the cost but also improves the milling efficiency. Especially in the long-distance full-water stable layer complex road milling working conditions, when the milling depth is greater than 50cm and the milling distance is 2000m, the traditional milling drum needs to replace 40-50 milling picks, while the technical solution of the present invention only needs to replace 20-25 milling picks, which greatly saves costs, reduces the replacement time of milling picks, and improves construction efficiency.

Claims

1. A milling drum for a road milling machine, comprising a milling drum base and N milling picks, characterized in that The milling drum base body has a middle section area including the location of the throwing plate and two side areas adjacent to the middle section area, and the milling picks include high-wear-resistant picks and high-toughness picks. The high-toughness picks are distributed in the middle section area of ​​the milling drum base body, and the high-wear-resistant picks are distributed in the two side areas of the milling drum base body; The milling pick comprises a main alloy part and a tooth body, wherein the main alloy part is welded to the top of the tooth body by brazing, the tooth body has a shank, and a tooth seat is provided on the milling drum base, and the tooth body is connected to the milling drum base through the tooth seat; The main alloy part of the high wear-resistant pick is made of cemented carbide, with a cobalt content of 5.5% to 6% and a hardness of 88 to 89 HRA; The main alloy part of the high-toughness pick is made of cemented carbide with a cobalt content of 6% to 6.5% and a hardness of 87 to 88.5 HRA.

2. The milling drum for a road milling machine according to claim 1, characterized in that: When the milling drum is used for shallow milling of asphalt surface layer, the N milling picks include 70%~90%×N high wear-resistant picks and 30%~10%×N high toughness picks; When the milling drum is used for milling a composite road surface of an asphalt surface layer and a water-stabilizing layer, the N milling picks include 30% to 70% × N high-wear-resistant picks and 30% to 70% × N high-toughness picks; When the milling drum is used for milling a complex road surface with a full water-stable layer, the N milling picks include 10% to 30% × N highly wear-resistant picks and 70% to 90% × N highly tough picks.

3. The milling drum for a road milling machine according to claim 1, characterized in that: The tooth body of the highly wear-resistant pick is provided with a groove, which is used to reduce the resistance of the milling drum when it is working and improve the working efficiency.

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