Public rotation milling and digging power head

Abstract

The invention discloses a revolution and rotation milling and digging power head which comprises a rotation milling and digging assembly, a revolution and rotation support, a revolution motor, a speed reducer, a connecting plate, a rotary connector, a slag suction pipe and other key components. The rotation milling and digging assembly is mounted below the revolution slewing bearing through a connecting plate and is responsible for rock crushing operation; the revolution slewing bearing bears the axial force, the radial force and the overturning force of the rotation milling and digging assembly; the revolution motor and the speed reducer drive the revolution slewing bearing to drive the rotation milling and digging assembly to move along a circle to form a circular hole wall; the rotary connector and the revolution slewing bearing are coaxially arranged, power is provided for the rotation milling and digging assembly through the hydraulic pump station, and the cutting tooth disc and the point type impact tool are driven to rotate. The slag suction pipe not only bears counter-acting force and downward pressure transmission during rock breaking, but also serves as a negative pressure slag outlet channel. The revolution and rotation milling and digging power head can be used as a component of modularized vertical milling and digging hole-forming equipment, plays a role in breaking rocks in excavation construction of a vertical hole pile foundation, and is used for solving the problems of breaking rocks and forming holes in hole pile foundation construction of hard rock geology in mountainous areas.

Description

Technical Field

[0001] This invention belongs to the field of power transmission line engineering, specifically, it relates to a rotary milling power head, which is suitable for drilling operations of power transmission line pile foundations under hard rock geological conditions in mountainous areas. Background Technology

[0002] The locations of power transmission line towers in mountainous areas are mostly situated in high mountains and deep valleys, with complex terrain and construction environments. The geological conditions are mainly hard rock, which poses great difficulties for the excavation and construction of large-diameter vertical bored pile foundations for power transmission towers. In terms of rock breaking technology, traditional blasting is limited by poor controllability of the rock breaking range and safety and environmental factors; hydraulic breakers and rock drills can only break small areas of rock, resulting in low efficiency; splitting methods require an air-supported surface, which is not suitable for drilling large-diameter vertical holes in solid rock. In the field of large-diameter (1-2m) vertical drilling machinery, rotary drilling rigs use hydraulic motors to drive the drill rod to rotate, and the bottom cutting tooth drill bit cuts the rock and soil. The drill cuttings are lifted to the outside of the hole by the spiral blades. They are only suitable for low-strength rock and soil, and have insufficient capacity for hard rock excavation. In addition, they are large in size and weight, and it is difficult to reach the work site in mountainous terrain without roads. The vertical shaft excavation equipment used in tunnels and coal mines is huge and suitable for ultra-large diameter (greater than 2m) deep-space construction at fixed points. However, it is not suitable for point-to-line distribution construction of power transmission line tower sites. There is a need to develop new equipment that can vertically form circular holes, has strong rock breaking ability in hard rock, and is miniaturized, modular, and highly mobile.

[0003] To address the aforementioned problems, CN114000553A, CN114030090A, CN216442840U, and other methods have proposed various techniques for cutting rock and soil. These techniques utilize a hexagonal drive shaft to rotate different cutting heads vertically, while the entire cutting device rotates horizontally. The cutting device can be moved under the drive of a lifting device to drill circular holes in the rock and soil. These methods use simple, single-piece cemented carbide cutting tools, which are lightweight and cannot cut hard rock. The tool's revolution and rotation are driven by mechanical transmissions such as chains and gears, resulting in low efficiency and a tendency to jam upon contact with hard rock. Therefore, these methods have insufficient rock-breaking capacity and are only suitable for soft rock geology (≤20MPa).

[0004] Milling technology is highly modular and efficient in breaking rock, and has been applied to horizontal drilling projects for tunnels, ditches, and municipal pipelines. Based on milling technology, CN115898280A proposes a drilling scheme that uses a single vertical milling head installed on a rotary platform for local rock breaking, hydraulic cylinders to control the tilt angle and position of the milling head for large-area rock breaking, a lifting bucket for material discharge, and a casing for lifting and lowering. CN111877972A and CN111877972B propose a rock breaking scheme that uses multiple cutting head assemblies (milling heads) for rock breaking, hydraulic cylinders to adjust the angle of the cutting head assemblies, a grab bucket for material discharge, and hydraulic cylinders for lifting and lowering. While these solutions address the problems of hard rock crushing and drilling to some extent, they all encounter several challenges in practical operation. For example, adjusting the milling head angle using hydraulic cylinders involves changes in the power head's position in the vertical direction, requiring corresponding adjustments to the lifting mechanism. However, ensuring the appropriate position for contact with hard rock and achieving efficient rock breaking remains a challenge. During rock breaking, the entire frame bears complex forces in the transverse, longitudinal, and torsional directions. Adjusting the power head position with hydraulic cylinders alters the stress structure of the entire device, making the design and strength of the frame difficult to guarantee. Using lifting buckets or grab buckets for material discharge only allows for partial discharge in space and intermittent discharge in time, affecting overall drilling efficiency. Currently, drilling diameters for power transmission line foundations within the 1.2-2m range requires significant power, but installing complex power and discharge devices within relatively confined spaces presents another challenge.

[0005] The root cause of these problems lies in the insufficient power of existing rock-breaking equipment, inflexible structural design, lack of efficient slag removal mechanism, and poor adaptability to complex mountainous terrain and hard rock geology, making it difficult to meet the needs of efficient, precise, and environmentally friendly mechanized construction. Summary of the Invention

[0006] To address the problems existing in the prior art, this invention provides a rotating milling power head that, through the rotation of dual milling heads for rock breaking and revolution for hole forming, combined with a negative pressure slag removal device, can form a circular hole on the entire end face in medium to high hard rock. This invention is a component of modular vertical milling and hole forming equipment, playing a rock-breaking role in the excavation and construction of vertical pile foundations, and is used to solve the problems of rock breaking and hole forming in the construction of pile foundations in hard rock geology in mountainous areas.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A rotating milling power head includes: a rotating milling assembly, a rotating bearing, a rotating motor and a reducer, two connecting plates, a rotary connector, and a slag suction pipe; two sets of the rotating milling assemblies are installed below the rotating bearing via the connecting plates, rotating to break rocks; the rotating bearing bears the axial, radial, and overturning forces of the two rotating milling assemblies; the rotating motor and reducer are fixed above the rotating bearing, driving the rotating bearing to move the rotating milling assemblies circumferentially to form a circular hole wall; the rotary connector is coaxially arranged with the rotating bearing, the fixed outer sleeve of the rotary connector is connected to a hydraulic pump station via an oil pipe, and the part of the rotating shaft of the rotary connector extending below the rotating bearing is connected to the rotating milling assembly via an oil pipe, driving the cutting tooth disk and its point impact cutter in the rotating milling assembly to rotate; the slag suction pipe is connected to the rotating bearing, bearing the reaction force and transmitting the downward pressure when the rotating milling power head breaks rocks, and also serving as a channel for negative pressure slag discharge.

[0008] Furthermore, the two sets of self-rotating milling components are installed at an angle and crosswise on the revolution slewing bearing via connecting plates. The tilt angles of the self-rotating milling components relative to the revolution slewing bearing are equal, and the self-rotating milling components are offset relative to the center of the revolution slewing bearing, ensuring that one set of self-rotating milling components can break the rock in the blind zone between the other set of self-rotating milling components when it revolves.

[0009] Furthermore, the self-rotating milling assembly includes: a self-rotating motor, a gear transmission mechanism, an internal milling head, an external milling head, and a housing. The self-rotating motor is installed on the input port of the gear transmission mechanism, and the two output ports of the gear transmission mechanism are located on both sides of the end of its housing, and the two output ports are on the same straight line; the internal milling head is installed on the output port of the gear transmission mechanism near the center of rotation, and the external milling head is installed on the output port of the gear transmission mechanism away from the center of rotation; the self-rotating motor transmits power to the cutting disc and the point impact cutter through the gear transmission mechanism, driving them to rotate and break the rock and soil they contact.

[0010] Furthermore, the inner and outer milling heads of the self-rotating milling assembly consist of a cutting tooth drum, a cutting tooth disc, steel balls, a certain number of tool bases, and point impact tools. The cutting tooth drum consists of a cylindrical sleeve with a base at one end, a cutting tooth base, and cutting teeth. The bottom surface of the cutting tooth disc is mounted on the baseless end of the cylindrical sleeve of the cutting tooth drum, forming a closed space with the cutting tooth drum. A large number of small-diameter steel balls are placed in the closed space. The diameter of the steel balls should be less than 1 / 10 of the inner diameter of the cutting tooth disc, and the total number of steel balls should fill between 1 / 3 and 1 / 2 of the closed space to increase the cutting force and reduce vibration caused by springback. The cutting tooth drum and the cutting tooth disc are fixed on the shaft of the gear transmission mechanism of the self-rotating milling assembly.

[0011] Furthermore, the tool base is welded to the cutting tooth drum and the cutting tooth disc, and the point impact tool equipped with a carbide cutting tip is mounted on the tool base by a retaining ring.

[0012] To achieve better rock-breaking results, the point-impact cutting tools are arranged in a regular pattern of multiple spiral lines on the cutting drum; the number N of cutting tools on the circumference of a single spiral line on the cutting drum should not be less than:

[0013] N≥0.4πDP

[0014] Where N is the number of cutters on the circumference of a single-row helical line; D is the outer diameter of the cutting drum, in meters; and P is the uniaxial saturated compressive strength of the rock being cut, in MPa.

[0015] The spacing L between the upward-axis cutting tools of the cutting drum should not exceed:

[0016] L≤400d / P

[0017] Where L is the axial spacing between the cutting tools, m; d is the diameter of the carbide tip holder on the cutting tool, m; P is the uniaxial saturated compressive strength of the rock being tested, MPa;

[0018] The number of cutting tools on the cutting tooth disc is equal to the aforementioned N, and they are installed at equal intervals on the circumference of the cutting tooth disc.

[0019] The diameter of the drilled pile hole can be changed by replacing the cutting tooth drum of different lengths on the external milling head.

[0020] Furthermore, the slewing bearing consists of an outer ring pinion, an inner ring gear, a fixed-end upper mounting plate, a rotating-end lower mounting plate, and peripheral guard plates. The outer ring pinion is connected to the output shaft of a motor and reducer mounted on the fixed-end upper mounting plate. Driven by the outer ring pinion, it rotates the inner ring gear and the rotating-end lower mounting plate fixed to it. Simultaneously, it drives the connecting plate on the lower mounting plate to revolve with the self-rotating milling assembly to form a circular hole wall.

[0021] Furthermore, the connecting plate is a trapezoidal steel plate with reinforcing ribs and flanges at both ends. One flange is fixed to the lower mounting plate of the slewing end of the revolution bearing by high-strength bolts, and the other flange is fixed to the housing of the self-rotating milling assembly by detachable bolts.

[0022] Furthermore, the rotary connector includes: a fixed outer sleeve, a rotating shaft, a sealing assembly, a bearing, and a fixed seat. The fixed outer sleeve and the rotating shaft have four corresponding channels: two inlet channels, one return channel, and one outlet channel, used to stably supply oil to the two self-rotating motors during revolution. The outer sleeve of the rotary connector is connected to its fixed seat, which is fixedly connected to the mounting plate on the fixed end of the slewing bearing. The rotating shaft of the rotary connector is fixedly connected to the lower mounting plate on the rotating end of the slewing bearing, and can rotate with the revolution to stably supply oil to the self-rotating motors. The two inlet channels of the rotating shaft are respectively connected to the hydraulic oil input ports of the two self-rotating motors. The return channels of the two self-rotating motors are merged into one channel and connected to the return channel of the rotating shaft. The outlet channels of the two self-rotating motors are merged into one channel and connected to the outlet channel of the rotating shaft.

[0023] Furthermore, the slag suction pipe serves as both a torque transmission channel and a slag discharge channel. The slag suction pipe is inserted into the revolution and slewing bearing. The portion of the slag suction pipe extending above the revolution and slewing bearing is connected to an external material extraction device. The portion of the slag suction pipe extending below the revolution and slewing bearing is located between the rotation ranges of the two self-rotating milling components, and its height extending below the revolution and slewing bearing is higher than the lowest position of the rotation range of the two self-rotating milling components.

[0024] Furthermore, the rotary connector has a through hole at its center, and the slag suction pipe is installed in the central circular hole of the rotary connector, so that the rotary connector, the slag suction pipe, and the revolution and slewing bearing are coaxially arranged.

[0025] Furthermore, the slag suction pipe consists of a circular guide tube, a drill rod connecting plate, and a connecting support. A flange is welded to the upper end of the circular guide tube for connecting the drill rod and for negative pressure slag extraction; the middle section of the circular guide tube passes through the hole in the center of the drill rod connecting plate and is welded to the drill rod connecting plate; the drill rod connecting plate is connected to the mounting plate on the fixed end of the slewing bearing via the connecting support; the lower section of the circular guide tube passes through the central circular hole of the rotating shaft of the rotary connector and extends above the inner milling head of the self-rotating milling assembly.

[0026] Furthermore, the lowest end of the circular guide tube of the slag suction pipe has an arc-shaped cover. The arc shape is parallel to the line connecting the inner milling head cutter of the self-rotating milling assembly. This is used to collect the gravel moving due to inertia during the rotation of the inner milling head cutter into the circular guide tube. The distance between the bottom of the arc-shaped cover and the line connecting the inner milling head cutter is controlled to be less than 1 / 3 of the inner diameter of the circular guide tube. This reduces the probability of gravel with a diameter greater than 1 / 3 of the inner diameter of the circular guide tube entering the circular guide tube, preventing blockage. On the circular guide tube at the upper end of the arc-shaped cover, a row of air guide holes with a diameter of approximately 1 cm is arranged according to a cylindrical spiral pattern. The angle between the air guide holes on the circumference is 60 degrees, and the spacing between the air guide holes along the length of the guide tube is 1 / 10 of the inner diameter of the guide tube. This utilizes the Venturi effect to create negative pressure at the collection point, giving the gravel and slag a greater acceleration and creating a spiral motion. This allows the slag and slag to move vertically in the pipe with the longest diameter of the gravel aligned with the airflow direction, reducing the probability of blockage. The bottom of the arc-shaped cover and the circular conduit are coated with a wear-resistant and non-stick PTFE coating to prevent wet and sticky materials from adhering to the conduit wall.

[0027] The beneficial effects of this invention are:

[0028] 1) High-efficiency rock breaking: The self-rotating milling component is equipped with point impact cutters with carbide cutter heads arranged in a certain pattern. The self-rotating motor is driven by a hydraulic pump station through a rotary connector, which reduces power loss and can efficiently cover and break hard rock on the entire end face.

[0029] 2) Precision hole formation: The milling head is driven to revolve by the slewing bearing, and the downward pressure is generated under the action of the drill rod to form a vertical circular hole; the diameter of the drilled pile hole can be changed by replacing the cutting tooth drum of different lengths on the external milling head.

[0030] 3) High-efficiency slag removal: Through a series of measures such as the soil throwing of the self-rotating milling component, the arc-shaped cover on the slag suction pipe, the matching of the distance between the cover and the line connecting the inner milling head cutter, the setting of the spiral air guide hole, and the coating of the bottom of the arc-shaped cover and the circular guide tube with a wear-resistant and non-stick coating, the high efficiency of negative pressure slag removal and the adaptability to various materials are ensured.

[0031] 4) This invention achieves efficient rock breaking, precise hole formation, and efficient negative pressure slag removal through component collaboration, solving the construction problems of bored pile foundations under hard rock geological conditions in mountainous areas. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the usage state of the present invention. Figure 1 ;

[0033] Figure 2 This is a schematic diagram of the usage state of the present invention. Figure 2 ;

[0034] Figure 3 This is a schematic diagram of the usage state of the present invention. Figure 3;

[0035] Figure 4 This is a schematic diagram of the usage state of the present invention. Figure 4 ;

[0036] Figure 5 This is a schematic diagram of the usage state of the present invention. Figure 4 ;

[0037] Figure 6 This is a schematic diagram of the structure of the present invention. Figure 1 ;

[0038] Figure 7 This is a schematic diagram of the structure of the present invention. Figure 2 ;

[0039] Figure 8 This is a schematic diagram of the structure of the present invention. Figure 3 ;

[0040] Figure 9 This is a schematic diagram of the cross-sectional structure of the gear transmission mechanism, the internal milling head, and the external milling head.

[0041] Figure 10 Schematic diagram of the slewing bearing structure Figure 1 ;

[0042] Figure 11 Schematic diagram of the slewing bearing structure Figure 2 ;

[0043] Figure 12 Schematic diagram of the slewing bearing structure Figure 2 ;

[0044] Figure 13 Schematic diagram of the connecting plate structure Figure 1 ;

[0045] Figure 14 Schematic diagram of the connecting plate structure Figure 2 ;

[0046] Figure 15 This is a schematic diagram of a rotary connector structure;

[0047] Figure 16 This is a schematic diagram of the cross-sectional structure of the rotary connector;

[0048] Figure 17 Schematic diagram of the slag suction pipe structure Figure 1 ;

[0049] Figure 18 Schematic diagram of the slag suction pipe structure Figure 2 ;

[0050] Figure 19 This is a schematic diagram of the structure of the present invention. Figure 4 ;

[0051] Figure 20 for Figure 19 Schematic diagram of the cross-sectional structure of the middle AA section;

[0052] Figure 21 This is a schematic diagram of the internal milling head / external milling head structure;

[0053] Figure 22 This is a schematic diagram of the connection structure between the internal and external milling heads;

[0054] Figure 23 for Figure 22 Cross-sectional structural diagram;

[0055] Figure 24 A schematic diagram of the installation structure of the internal and external milling heads;

[0056] Figure 25 Schematic diagram of the milling head structure for replacing the long cutting tooth drum in this invention. Figure 1 ;

[0057] Figure 26 Schematic diagram of the milling head structure for replacing the long cutting tooth drum in this invention. Figure 2 ;

[0058] Figure 27 This is a partial cross-sectional structural diagram of the present invention;

[0059] Figure 28 for Figure 27 Schematic diagram of the cross-sectional structure of the middle AA section;

[0060] In the diagram: 100. Rotary milling head; 101. Rotary milling assembly; 1011. Rotary motor; 1012. Gear transmission mechanism; 1013. Internal milling head; 10131. Cutting gear drum; 10132. Cutting gear disc; 10133. Steel ball; 10134. Tool base; 10135. Point impact tool; 1014. External milling head; 1015. Housing; 1016. Milling head shaft; 102. Rotary slewing bearing; 1021. Outer ring pinion; 1022. Inner ring gear; 1023. Fixed end upper mounting plate; 1024. Rotary end lower mounting plate; 1025. Circumference... Side guard plate; 103. Revolutionary motor and reducer; 104. Connecting plate; 105. Rotary connector; 1051. Fixed sleeve; 1052. Rotating shaft; 1053. Fixed seat; 1054. Sealing assembly; 1055. Bearing; 10511. Oil pipe channel inlet; 10521. Oil pipe channel outlet; 106. Slag suction pipe; 1061. Circular guide pipe; 10611. Arc-shaped cover; 10612. Air guide hole; 1062. Drill pipe connecting plate; 1063. Connecting support; 107. Soil and rock layer; 108. Drill pipe; 109. Hydraulic oil pipe; 110. Hydraulic pump station; 111. Slag; Detailed Implementation

[0061] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. However, it should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of the invention.

[0062] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention.

[0063] like Figure 1-28 As shown, a self-rotating milling power head 100, as the core component of a modular vertical milling drilling equipment, is used to solve the construction problems of bored pile foundations under hard rock geological conditions in mountainous areas; the power head achieves efficient rock breaking, precise hole formation, and efficient negative pressure slag removal through the coordinated operation of the following components.

[0064] like Figure 1-28 As shown, the self-rotating milling power head 100 includes: a self-rotating milling assembly 101, a slewing bearing 102, a slewing motor and reducer 103, two connecting plates 104, a rotary connector 105, and a slag suction pipe 106; the two sets of self-rotating milling assemblies 101 are installed below the slewing bearing 102 via the connecting plates 104, and rotate under the drive of their motors to break the rock and soil layer 107, producing debris 111; the slewing bearing 102 bears the axial, radial, and overturning forces of the two self-rotating milling assemblies 101; the slewing motor and reducer 103 are fixed to the slewing bearing 102. Above 02, the slewing bearing 102 drives the self-rotating milling assembly 101 to move circumferentially to form a circular hole wall; the rotary connector 105 is coaxially arranged with the slewing bearing 102, the upper end of the rotary connector 105 is connected to the hydraulic pump station 110 through the external hydraulic oil pipe 109, and the lower end of the rotary connector 105 is connected to the self-rotating milling assembly 101 through its own oil pipe, driving the self-rotating milling assembly 101 to rotate; the slag suction pipe 106 is connected to the slewing bearing 102, bearing the reaction force and transmitting the downward pressure when the self-rotating milling power head 100 breaks the rock, and at the same time serving as a channel for negative pressure slag discharge.

[0065] like Figure 5-9As shown in Figures 13-14, 19, 25, 26, and 27, the two sets of self-rotating milling components 101 are mounted on the revolution slewing bearing 102 at an angle and crosswise using bolts through the connecting plate 104. The revolution slewing bearing 102 has multiple holes to ensure that the connecting plate 104 is installed in different positions, so as to ensure that the tilt angle of the self-rotating milling component 101 relative to the revolution slewing bearing 102 is equal, and the self-rotating milling component 101 is offset from the center of the revolution slewing bearing 102, thereby ensuring that one set of self-rotating milling components can break the rock in the blind zone between the other set of self-rotating milling components when it revolves.

[0066] like Figure 1-9 As shown in Figures 19-28, the self-rotating milling assembly 101 includes: a self-rotating motor 1011, a gear transmission mechanism 1012, an inner milling head 1013, an outer milling head 1014, and a housing 1015. The self-rotating motor 1011 is installed on the input port of the gear transmission mechanism 1012, and the two output ports of the gear transmission mechanism 1012 are located on both sides of the end of its housing 1015, and the two output ports are located on the same straight line. The inner milling head 1013 is installed on the output port of the gear transmission mechanism 1012 near the center of rotation, and the outer milling head 1014 is installed on the output port of the gear transmission mechanism 1012 away from the center of rotation. The self-rotating motor 1011 transmits power to the cutting disc and the point impact cutter through the gear transmission mechanism 1012, driving them to rotate. In actual operation, only a single point impact cutter contacts the rock and soil layer and is subjected to force at any given moment. Under the torque of the self-rotating motor 102, the force is converted into the impact force on the point impact cutter, ensuring the crushing of medium-high hard rock.

[0067] like Figure 1-9 As shown in Figures 19-28, the self-rotating milling assembly 101 further includes a milling head shaft 1016. The inner milling head 1013 and the outer milling head 1014 are connected to the two output ports of the gear transmission mechanism 1012 through the milling head shaft 1016, and the power of the gear transmission mechanism 1012 is transmitted to the inner milling head 1013 and the outer milling head 1014 through the milling head shaft 1016.

[0068] like Figure 21-24As shown, the inner milling head 1013 and outer milling head 1014 of the self-rotating milling assembly 101 are both composed of a cutting tooth drum 10131, a cutting tooth disc 10132, a steel ball 10133, a certain number of tool bases 10134, and point impact tools 10135; the cutting tooth drum 10131 is composed of a cylindrical sleeve with a base at one end, a cutting tooth base, and cutting teeth; the bottom surface of the cutting tooth disc 10132 is installed on the cylindrical sleeve of the cutting tooth drum 10131 without a base. The cutting disc 10132 and the cutting drum 10131 form a closed space. A large number of small-diameter steel balls 10133 are arranged in the closed space. The diameter of the steel balls 10133 should be less than 1 / 10 of the inner diameter of the cutting disc 10132. The total number of steel balls 10133 should fill between 1 / 2 and 3 / 4 of the closed space to increase the cutting force and reduce the vibration caused by springback. The cutting drum 10131 and the cutting disc 10132 are fixed on the shaft of the gear transmission mechanism 1012 of the self-rotating milling assembly 101.

[0069] The tool base 10134 is welded to the cutting tooth drum 10131 and the cutting tooth disc 10132, and the point impact tool 10135 equipped with carbide cutting tips is mounted on the tool base 10134 by a retaining ring.

[0070] To achieve better rock-breaking results, the point-impact cutting tools 10135 are arranged in a multi-row spiral pattern on the cutting drum 10131; the number N of cutting tools on the circumference of a single spiral line on the cutting drum 10131 should not be less than:

[0071] N≥0.4πDP

[0072] Where N is the number of cutters on the circumference of a single-row helical line; D is the outer diameter of the cutting drum 10131, in meters; P is the uniaxial saturated compressive strength of the rock being cut, in MPa.

[0073] The axial spacing L between the cutting tools of the 10131 cutting tool drum should not exceed:

[0074] L≤400d / P

[0075] Where L is the axial spacing between the cutting tools, m; d is the diameter of the carbide tip holder on the cutting tool, m; P is the uniaxial saturated compressive strength of the rock being tested, MPa;

[0076] The number of cutting tools on the cutting tooth disk 10132 is equal to the above-mentioned N, and they are installed at equal intervals on the circumference of the cutting tooth disk 10132.

[0077] The diameter of the drilled pile hole can be changed by replacing the cutting tooth drum 10131 of different lengths on the external milling head 1014.

[0078] like Figure 1-7As shown in Figures 10-12, the revolution slewing bearing 102 is composed of an outer ring pinion 1021, an inner ring gear 1022, a fixed end upper mounting plate 1023, a slewing end lower mounting plate 1024, and a peripheral guard plate 1025. The outer ring pinion 1021 is connected to the output shaft of the motor and reducer mounted on the fixed end upper mounting plate 1023. Under its drive, the inner ring gear 1022 and the slewing end lower mounting plate 1024 fixed to it rotate, and at the same time, the connecting plate 104 on the lower mounting plate revolves with the self-rotating milling assembly 101 to form a circular hole wall.

[0079] like Figure 1-7 As shown in Figures 13-14, 19, 20, and 25-28, the connecting plate 104 is a trapezoidal steel plate with reinforcing ribs and flanges at both ends. The material used is Q345 high-strength steel with a thickness greater than 12mm. One flange is fixed to the lower mounting plate 1024 of the rotating end of the revolution slewing bearing 102 by high-strength bolts, and the other flange is fixed to the housing 1015 of the self-rotating milling assembly 101 by detachable bolts.

[0080] like Figure 5-7 As shown in Figures 10-12, 15-16, and 27, the rotary connector 105 includes: a fixed outer sleeve 1051, a rotating shaft 1052, a sealing assembly, a bearing, and a fixed base 1053. The fixed outer sleeve 1051 and the rotating shaft 1052 have four corresponding channels: two oil inlets, one oil return, and one oil discharge, used to stably supply oil to the two self-rotating motors 1011 during revolution. The outer sleeve of the rotary connector 105 is connected to its fixed base 1053, and the fixed base 1053 is fixedly connected to the mounting plate 1023 on the fixed end of the slewing bearing. The rotating shaft 1052 of the rotary connector 105 is fixedly connected to the lower mounting plate 1024 of the slewing end of the slewing bearing, and can rotate with the revolution to stably supply oil to the self-rotating motor 1011. The two oil inlet channels of the rotating shaft 1052 are connected to the hydraulic oil input ports of the two self-rotating motors 1011 respectively through oil pipes. The oil return ends of the two self-rotating motors 1011 are merged into one through oil pipes and connected to the oil return channel of the rotating shaft 1052. The oil discharge ends of the two self-rotating motors 1011 are merged into one through oil pipes and connected to the oil discharge channel of the rotating shaft 1052.

[0081] like Figure 1 , 2 As shown in Figures 5, 6, 17, 18, 19, 20, and 25-28, the slag suction pipe 106 is inserted into the revolution-slewing bearing 102. The portion of the slag suction pipe 106 extending above the revolution-slewing bearing 102 is connected to an external material extraction device. The portion of the slag suction pipe 106 extending below the revolution-slewing bearing 102 is located between the rotation ranges of the two self-rotating milling components 101, and the height of the portion extending below the revolution-slewing bearing 102 is higher than the lowest position of the rotation range of the two self-rotating milling components 101.

[0082] like Figure 15-16 As shown, the rotary connector 105 has a through hole in the center, and the slag suction pipe is installed in the central circular hole of the rotary connector, so that the rotary connector, the slag suction pipe, and the revolution and slewing bearing are coaxially arranged.

[0083] like Figure 1 , 2 As shown in Figures 5, 6, 17, 18, 19, 20, and 25-28, the slag suction pipe 106 consists of a circular guide tube 1061 made of Q345 material, a drill rod connecting plate 1062, and a connecting support 1063. The upper end of the circular guide tube 1061 is welded with a flange for connecting the drill rod 108 and for negative pressure extraction of slag. The middle section of the circular guide tube 1061 passes through the hole in the middle of the drill rod connecting plate 1062 and is welded to the drill rod connecting plate 1062. The drill rod connecting plate 1062 is connected to the mounting plate 1023 on the fixed end of the slewing bearing 102 through the connecting support 1063. The lower section of the circular guide tube 1061 passes through the central circular hole of the rotating shaft 1052 of the rotary connector 105 and extends into the inner milling head 1013 of the self-rotating milling assembly 101.

[0084] like Figure 1 , 2 As shown in Figures 5, 6, 17, 18, 19, 20, and 25-28, the lowest end of the circular guide tube 1061 of the slag suction pipe 106 has an arc-shaped cover. The arc shape is parallel to the line connecting the inner milling head 1013 of the self-rotating milling assembly 101. This cover is used to collect the gravel that moves due to inertia when the inner milling head 1013 rotates into the circular guide tube 1061. The distance between the bottom of the arc-shaped cover and the line connecting the inner milling head 1013 is controlled to be less than 1 / 3 of the inner diameter of the circular guide tube 1061, so as to reduce the probability of gravel with a diameter greater than 1 / 3 of the inner diameter of the circular guide tube 1061 entering the circular guide tube 1061 and prevent blockage of the guide tube.

[0085] On the circular guide tube 1061 at the upper end of the arc-shaped cover, air guide holes with a diameter of about 1 cm are set according to the cylindrical spiral pattern. The distribution angle of the air guide holes on the circumference is 60 degrees, and the spacing of the air guide holes along the length of the guide tube is 1 / 10 of the inner diameter of the guide tube. The spiral line is longer than 1.5 times the inner diameter of the circular guide tube 1061, so as to utilize the Venturi effect to form a negative pressure at the convergence point, giving the crushed stone and soil a large acceleration and forming a spiral motion, allowing the soil and soil to move in the pipe in a vertical posture with the longest diameter of the crushed stone and the airflow direction in the same direction, reducing the probability of blockage. The bottom of the arc-shaped cover and the circular guide tube 1061 are coated with a wear-resistant and non-stick polytetrafluoroethylene coating to prevent wet and sticky materials from sticking to the pipe wall.

[0086] Compared with existing technologies, the rotary / autorotation milling power head has the following significant technical advantages:

[0087] High-efficiency rock breaking: The dual milling head 101 is equipped with carbide milling teeth 1011, and the self-rotating motor 102 provides 1225Nm of torque. It can break hard rock with a single-axis compressive strength of 55MPa. The rock breaking parameters include a single-point force of 550N and a contact area of ​​1mm. 2 The calculation shows that when all 8 milling teeth are subjected to force simultaneously, the required torque is 814 N·m, and the rock-breaking speed reaches 0.5 m / h, thus improving efficiency.

[0088] Precise hole forming: The revolution motor 105 provides 3000 N·m of torque and a maximum speed of 8 r / min. It drives the milling head 101 to revolve through the revolution slewing bearing 104 to form a circular hole with a diameter of 1.2-1.6 m. The connecting plate 103 adjusts the hole diameter through a detachable screw. The verticality deviation is ≤0.5% and the hole wall flatness is ≤5 mm.

[0089] High-efficiency slag removal: The slag suction pipe is 107mm in diameter with an inner wall roughness Ra<1.6μm. Combined with negative pressure material extraction (external extraction device pressure 68.6kPa), the slag particle diameter is ≤50mm, and the extraction speed is 0.5m / s. 3 / min, efficiency increased by a factor of two.

[0090] Modular design: The weight of components (such as connecting plate 103 weighing 100kg and slewing bearing weighing 150kg) is ≤350kg, which is suitable for 2t cableway transportation and can be assembled with the assistance of simple lifting machinery. The adjustment time of connecting plate 103 is ≤10 minutes and the disassembly time is ≤15 minutes, reducing labor intensity by 50%, which is superior to existing technologies (>2t, assembly >1 hour).

[0091] High stability: The revolution slewing bearing 104 has multiple built-in 20mm diameter roller bearings to withstand axial, radial and overturning forces. The rotary connector 106 is made of stainless steel with four channels and an oil leakage rate of <0.1ml / h, ensuring stable hydraulic supply and vibration amplitude ≤0.05mm.

[0092] This paper innovatively introduces milling technology into the vertical drilling of power transmission line pile foundations in mountainous hard rock geological conditions. A dual-rotation milling power head was designed, utilizing the rotation of two milling heads (101) for rock breaking and revolution for hole drilling. Combined with negative pressure slag removal and a modular structure, this solves the challenges of rock breaking and hole drilling in mountainous hard rock geological conditions (uniaxial compressive strength 55MPa) for pile foundation construction. These advantages enable the dual-rotation milling power head to achieve efficient rock breaking, precise hole drilling, and convenient assembly in mountainous hard rock geological construction, significantly improving construction efficiency and safety. It is suitable for complex terrain and scenarios with high environmental protection requirements.

[0093] The overall structure of the rotating milling power head, as the core component of the modular vertical milling drilling equipment, is responsible for breaking hard rock with a uniaxial compressive strength of not less than 55MPa and forming a vertical circular hole with a diameter of 1.2-1.6m. The rotating milling power head is composed of multiple modular components. It achieves efficient construction through rotating rock breaking, rotating hole forming, and negative pressure slag removal. Its modular structure is compatible with 2t cableway transportation.

[0094] The power head for both solar and rotary milling includes the following components:

[0095] The milling head 101 is arranged opposite to the free end of the power head. It has a transverse cylindrical structure with a diameter of about 370 mm, an axial length of 200 mm, and a weight of about 150 kg.

[0096] The milling head 101 housing is made of high-strength cast steel, with approximately 32 carbide milling teeth 1011 embedded on the surface. The single tooth bearing strength is ≥600MPa, and the wear resistance life is ≥10 years. It is configured to crush hard rock with a single-axis compressive strength of not less than 55MPa through self-rotation and is also suitable for soft soil excavation. The gear transmission mechanism is fixed to the connecting plate 103 by 8 M24 screws (shear tensile strength ≥850MPa). The screw hole diameter is 16mm, the spacing is 120mm, and they are evenly distributed around the flange.

[0097] Two self-rotating motors 102, each with a rated torque of 1225 N·m, a rated pressure of 25 MPa, a peak pressure of 36 MPa, a theoretical displacement of 314 ml / r, a continuous speed of 1-350 r / min, a maximum speed of 600 r / min, and a weight of 30.2 kg. Each self-rotating motor 102 is connected to the self-rotating shaft of the milling head 101 through a gear transmission mechanism (module 4, number of teeth 28, transmission ratio 2:1, efficiency ≥95%), and is fixed to the connecting plate 103 with 36 M14 screws (tensile strength ≥12.9 grade), with a pitch of 2 mm and a hole diameter of 10 mm, arranged in an equilateral triangle.

[0098] The connecting plate 103 is a rectangular steel plate, measuring 800mm × 630mm, with a thickness of 50mm and a weight of 60.8kg. It is coated with a 0.2mm thick epoxy anti-corrosion coating, providing a moisture corrosion resistance life of ≥5000 hours. One end is secured by 12 M35 bolts (shear strength ≥950N / mm²). 2 The hole (26mm diameter) is fixed to the revolution slewing bearing 104. The other end is connected to the gear transmission mechanism through 8 M24 detachable screws (16mm diameter, 50-100mm spacing). The hole positions are configured in 4 groups, which can be used to form holes with a diameter of 1.2-1.6m. The adjustment time is ≤5 minutes.

[0099] The slewing bearing 104 is a circular high-strength steel structure with a diameter of 500mm, a thickness of 80mm, a weight of 89.6kg, and a yield strength ≥720MPa. It contains 100 20mm diameter roller bearings and can withstand an axial force of 3.5t, a radial force of 1.2t, and an overturning force of 600N·m. The bottom is fixed to the connecting plate 103 by a full circumferential weld (thickness 8mm, strength ≥650MPa), and the top is fixed by 12 M36 bolts (shear strength ≥1000N / mm²). 2 105 flange sleeve (inner diameter 480mm, thickness 25mm) for connecting to the revolution motor (hole diameter 28mm).

[0100] The total displacement of the revolution motor 105 is 1050.5 ml / r, the rated pressure is 20 MPa, the rated torque is 3000 N·m, the output speed is 1-76 r / min (maximum 8 r / min), the weight is 29.4 kg, and it is equipped with a C2.5 reducer (reduction ratio 5.5, efficiency ≥96%). The revolution motor 105 is connected to the outer ring of the revolution slewing bearing 104 through gears (module 5, number of teeth 36, transmission ratio 2.5:1), and fixed to 8 M20 bolts (tensile strength ≥14.8 grade, hole diameter 14 mm), arranged in a square, and the heat dissipation temperature of the aluminum alloy shell is ≤55℃.

[0101] The rotary connector 106 is cylindrical, with a diameter of 150mm, an axial length of 108mm, and a weight of 24.8kg. The main body is made of high-strength steel, and the internal four channels (two for oil inlet, one for oil return, and one for oil outlet) are made of stainless steel, with a corrosion resistance life of ≥12 years. It is designed for a pressure of 25MPa, a rotation speed of 8r / min, and an oil leakage rate of <0.1ml / h. It is secured by eight M14 screws (shear strength ≥900N / mm²). 2 The 10mm diameter hole is fixed on the slewing bearing 104 and connected to the hydraulic pump station oil pipe (20mm diameter, pressure 32MPa) via a quick clamp (pressure ≥40MPa). The sealing ring is made of fluororubber, with a temperature resistance of 150℃ and a service life of ≥1500 hours.

[0102] The slag suction pipe 107 is a hollow cylindrical steel structure with a diameter of 100 mm, a wall thickness of 5 mm, an axial length of 200 mm, and a weight of 9.8 kg. Its inner wall roughness Ra < 1.4 μm, and its surface is coated with a 0.1 mm thick anti-corrosion coating. It is located between the two adjacent milling heads 101 of the two self-rotating milling components, coaxial with the revolution slewing bearing 104, and is secured by four M12 bolts (shear strength ≥ 850 N / mm²). 2 The fixed flange (120mm in diameter, rubber gasket pressure resistance >0.2MPa) is connected to the external material extraction device, and the top is equipped with a rubber dust cover (110mm in diameter, 0.8mm thick).

[0103] The above components are constructed in the following order.

[0104] Cast the main body of the revolution and slewing bearing 104, with a precision machined inner diameter of 480mm, install 100 ball bearings, and fill with high-temperature grease (viscosity 4000mPa·s); the bottom is circumferentially welded with connecting plate 103 (weld height 8mm), and the top is drilled with 12 M36 bolt holes (accuracy ±0.05mm).

[0105] The connecting plate 103 is precision milled to an 800mm×630mm plane, sprayed with an epoxy anti-corrosion coating, and drilled with 12 M35 screw holes (bottom side) and 28 M24 screw holes (top side, 4 sets spaced 50-200mm apart); it is fixed to the revolution and slewing bearing 104 by 12 M35 bolts and connected to the gear transmission mechanism by 8 M24 screws.

[0106] The self-rotating motor 102 is assembled with gears (28 teeth, module 4) and fixed to the input port of the gear transmission mechanism by 6 M14 screws. The output gear shaft of the gear transmission mechanism is connected to the self-rotating shaft of the milling head 101 through a keyway (8mm wide, 4mm deep).

[0107] The gear transmission mechanism is a gearbox with one input and two outputs.

[0108] The revolution motor 105 is assembled with a C2.5 reducer (36 teeth, module 5), which is fixed to the top of the revolution slewing bearing 104 by 8 M20 bolts, and the gear meshes with the outer ring (gear ring diameter 120mm).

[0109] The rotary connector has a 106 cast stainless steel channel (4mm in diameter), is fitted with a fluororubber sealing ring, has 8 M14 threaded holes, is fixed to the revolution slewing bearing 104, and is connected to the oil pipe (quick clamp).

[0110] The suction pipe is precision machined to an inner diameter of 100mm, coated with an anti-corrosion coating, and has a welded bottom flange (4 M12 bolt holes). The top dust cover is installed (fixed with clips).

[0111] The above components work together as follows:

[0112] The self-rotating motor 102 drives the milling head 101 to rotate with a torque of 1225 N·m. Eight milling teeth (550 N per point) collide with 55 MPa rock, producing debris ≤50 mm. The orbital motor 105 drives the milling head 101 to revolve (8 r / min) through the orbital slewing bearing 104 with a torque of 3000 N·m, forming a 1.2-1.6 m circular hole with a verticality deviation <0.5%. The rotary connector 106 supplies oil to the self-rotating motor 102 at 25 MPa pressure through four channels (two inlets, one return, and one unloading), with an oil leakage rate <0.1 ml / h. The slag suction pipe 107 extracts debris (0.5 m) under negative pressure (68.6 kPa). 3 / min), with an inner wall Ra<1.4μm to reduce adhesion, and a dust cover to prevent foreign objects from entering; the connecting plate 103 can be adapted to the hole diameter (1.2-1.6m) by adjusting the screw hole position, and in the future, it can support the extension of the servo telescopic rod (accuracy ±1mm) to 2m.

[0113] The total weight of the self-rotating milling power head 100 is less than 1.5t. It is assembled in a modular manner and can be disassembled into a self-rotating milling component (150kg×2), a connecting plate 103 (60.8kg), a slewing bearing 104 (89.6kg), a self-rotating motor 102 (30.2kg×2), a slewing motor 105 (29.4kg), a rotary connector 106 (24.8kg), and a slag suction pipe 107 (9.8kg). Therefore, it is suitable for 2t cableway transportation. The modular components are connected by bolts and welding, which facilitates disassembly (≤15 minutes). The adjustment hole diameter of the connecting plate 103 takes ≤5 minutes, and the sealing ring replacement cycle is 12 months.

[0114] The precision structure enables efficient rock breaking, accurate hole formation, and negative pressure slag removal, while the modular design is suitable for construction in mountainous areas.

[0115] The transverse structure of the milling head 101 and the layout of the dual milling heads 101 demonstrate the rock-breaking performance of the carbide milling teeth 1011 and the hole diameter adaptation mechanism of the connecting plate 103, ensuring efficient hard rock crushing and precise large-diameter hole formation, while optimizing the discharge of debris.

[0116] In some examples, each milling head 101 is a transverse cylindrical shape with a diameter of 370 mm, an axial length of 200 mm, a wall thickness of 20 mm, and a weight of 150 kg. The main body is made of high-strength cast steel (yield strength ≥700 MPa), and the surface is inlaid with 32 carbide milling teeth 1011, with a single tooth size of 10 mm × 8 mm, a spacing of 15 mm, a bearing capacity of ≥600 MPa, and a wear life of ≥10 years. It is internally equipped with ball bearings (diameter 15 mm, quantity 60), which can withstand an axial force of 1.5 t and a radial force of 0.5 t, and a lubrication cycle of 6 months. The self-rotating shaft (diameter 50 mm, length 100 mm) is connected to the self-rotating motor 102 gear (module 4, 28 teeth, transmission ratio 2:1, efficiency ≥95%) through a keyway (width 8 mm, depth 4 mm), and the shaft end is fixed by 4 M16 screws (shear strength ≥850 MPa). The gear transmission mechanism is fixed to the connecting plate 103 by eight M24 screws (16mm hole diameter, 120mm spacing). The screw holes are arranged in a ring, and the disassembly time is ≤10 minutes.

[0117] The rock-breaking parameters are as follows:

[0118] Uniaxial compressive strength of rock: 55 MPa; Pressure: 550 MPa; Contact area: 1 mm² 2Single-point force: 550N; Simultaneous force milling teeth: 8 (1 / 4 of the total number of milling teeth); Radius: 0.185m; Torque: 814N·m.

[0119] The dual milling heads 101 are symmetrically arranged at the free end of the rotating milling power head 100, and synchronously revolve around the main shaft, excavating a blind zone of less than 5% of the hole area. The connecting plate 103 (800mm×630mm, 50mm thick) is connected to the gear transmission mechanism through 4 sets of M24 screw holes (spacing 50-200mm, accuracy ±0.05mm), adapting to a hole diameter of 1.2-1.6m, with an adjustment time of ≤5 minutes. In some other examples, the milling head 101 uses 4 servo telescopic rods (diameter 20mm, stroke 400mm, accuracy ±1mm) to extend to a hole diameter of 2m. The milling head 101 works in conjunction with the slag suction pipe 107107 interface (flange diameter 120mm, 4 M12 screw holes, rubber gasket pressure resistance >0.2MPa), with a slag discharge path angle of 30° and a blockage rate of <3%.

[0120] The construction order is as follows:

[0121] The main body of the cast milling head 101 is precision machined to an outer diameter of 370mm, inlaid with 32 milling teeth (15mm spacing), and equipped with 60 ball bearings and lubricated with grease; 8 M24 screw holes (accuracy ±0.03mm) are drilled on the gear transmission mechanism and fixed to the connecting plate 103 with screws.

[0122] The rotation shaft of the milling head 101 is connected to the gear transmission mechanism via a keyway and is secured by four M16 screws at the end.

[0123] The sequence of operation of each module in the self-rotating milling head 100 is as follows:

[0124] The self-rotating motor 102 (1225 N·m) drives the milling head 101 to rotate, and the 8 milling teeth crush the rock with a force of 550 N, with the debris ≤50 mm.

[0125] The revolution motor 105 drives the milling head 101 to revolve through the connecting plate 103, forming a 1.2-1.6m circular hole.

[0126] The debris is discharged along the slag suction pipe 107 (100mm in diameter), with a blind zone of <5%.

[0127] The milling head 101 generates noise ≤75dB and vibration ≤0.08mm during rotation, making it suitable for hard rock and soft soil; the milling teeth can be replaced individually (cycle 12 months), and the connecting plate 103 can be adjusted to support 2m expansion.

[0128] The layout of the horizontal milling head 101 and the double milling head 101 enables efficient rock breaking and precise hole formation, while optimizing the slag discharge path to improve construction efficiency.

[0129] The construction of the slewing bearing 104 and the slewing motor 105 demonstrates their ability to support the milling head 101 in revolution and withstand complex forces, ensuring the stability and accuracy of large-diameter hole formation.

[0130] The slewing bearing 104 is a circular high-strength steel structure with a diameter of 500mm, an inner diameter of 480mm, a thickness of 80mm, a weight of 89.6kg, and a yield strength ≥720MPa. It contains 100 ball bearings (20mm diameter, P5 precision grade), evenly distributed within the inner ring (60mm width). It can withstand an axial force of 3.5t, a radial force of 1.2t, and an overturning force of 600N·m. It requires 200g of grease for a 6-month service life. The bottom of the slewing bearing 104 is fixed to the connecting plate 103 via a full-circumferential weld (8mm thick, strength ≥650MPa), and the top is secured by 12 M36 bolts (shear strength ≥1000N / mm²). 2 The flange sleeve (diameter 550mm, thickness 25mm, material 45# steel) of the revolution motor 105 (hole diameter 28mm, accuracy ±0.05mm) is connected to the revolution slewing bearing 104 outer ring gear (module 5, number of teeth 96) meshes with the revolution motor 105 gear, with a transmission efficiency ≥96%.

[0131] The revolution motor 105 is hydraulically driven, with a total displacement of 1050.5 ml / r, rated pressure of 20 MPa, rated torque of 3000 N·m, output speed of 1-76 r / min (maximum 8 r / min), and a weight of 29.4 kg. It is equipped with a C2.5 reducer (reduction ratio 5.5, number of teeth 36, efficiency ≥96%), with an aluminum alloy housing (heat dissipation temperature ≤55℃). It is fixed to the top of the revolution slewing bearing 104 by 8 M20 bolts (tensile strength ≥14.8 grade, hole diameter 14 mm, spacing 80 mm). The gear (module 5, number of teeth 24) is connected to the reducer output shaft through a keyway (width 6 mm, depth 3 mm), meshing with the gear ring of the revolution slewing bearing 104, with a tooth backlash of 0.1 mm.

[0132] The construction sequence of the orbital motor 105 is as follows:

[0133] The main body of the cast revolution slewing bearing 104 is precision machined with an inner diameter of 480mm, and 100 ball bearings are installed and filled with grease. The bottom is circumferentially welded to the connecting plate 103 (weld height 8mm), and the top is drilled with 12 M36 screw holes (accuracy ±0.05mm). The revolution motor 105 is assembled with a C2.5 reducer, drilled with 8 M20 screw holes, and fixed to the revolution slewing bearing 104 with bolts, with gears meshing with the gear ring.

[0134] During operation, the revolution motor 105 drives the revolution slewing bearing 104104 with a torque of 3000 N·m, which in turn drives the milling head 101 to revolution (8 r / min); 100 ball bearings distribute axial, radial, and overturning forces, with vibration deviation ≤0.05 mm; the connecting plate 103 transmits the revolution force to the milling head 101, forming a 1.2-1.6 m circular hole with a verticality <0.5%; the revolution slewing bearing 104 can be disassembled in ≤15 minutes, the bolt connection facilitates maintenance, and the reducer lubrication cycle is 6 months.

[0135] Stable revolution and precise hole formation are ensured by a high-torque revolution motor 105 and a multi-bearing revolution slewing bearing 104, meeting the requirements of hard rock geological construction.

[0136] The construction of the rotary connector 106 demonstrates its ability to stably supply hydraulic oil during revolution, ensuring the efficient operation of the self-rotating motor 102.

[0137] The rotary connector 106 is cylindrical, with a diameter of 150mm, an axial length of 108mm, and a weight of 24.8kg. The main body is made of high-strength steel (yield strength ≥600MPa), and the internal four channels (two for oil inlet, one for oil return, and one for oil outlet) are made of stainless steel (SUS304, corrosion resistance life ≥12 years). The channel diameter is 4mm, the pressure resistance is 25MPa, and the oil leakage rate is <0.1ml / h. The sealing rings are made of fluororubber, with a temperature resistance of 150℃, a pressure resistance of 30MPa, and a lifespan ≥1500 hours. There are four sealing rings distributed at the channel interfaces. It is secured by eight M14 screws (shear strength ≥900N / mm²). 2 The screw holes (10mm diameter, 40mm spacing) are fixed to the top of the slewing bearing 104, with a screw hole accuracy of ±0.03mm. The oil pipe (20mm diameter, 2mm wall thickness, 32MPa pressure resistance) is connected via quick-connect clamps (pressure resistance ≥40MPa, clamping force 500N), with a sealing ring life ≥1000 cycles. The design speed is 8r / min, compatible with the self-rotating motor 102.

[0138] The construction sequence of the rotary connector 106 is as follows: cast stainless steel channel (wall thickness 1mm), install 4 fluororubber sealing rings, assemble the connector body; precision machine the outer diameter to 150mm, drill 8 M14 screw holes (accuracy ±0.03mm), fix it to the revolution slewing bearing 104 with screws; connect the oil pipe (quick clamp), and test the oil leakage rate (<0.1ml / h).

[0139] During operation, the two oil inlets supply hydraulic oil to the self-rotating motor 102 at a pressure of 25MPa, one oil return line recovers hydraulic oil, and the other oil discharges to release pressure.

[0140] With the slewing bearing revolving 104 revolutions (8 r / min), the sealing ring ensures an oil leakage rate of <0.1 ml / h.

[0141] A stable hydraulic supply supports the continuous operation of the self-rotating motor 102 (1225 N·m).

[0142] Quick clamp removal time ≤ 3 minutes, sealing ring replacement cycle 12 months, connector weight 24.8kg, suitable for cableway transportation.

[0143] A stable hydraulic supply is achieved during the revolution through stainless steel channels and fluororubber seals, supporting efficient rock breaking.

[0144] The self-rotating milling head 100, with the slewing bearing 104 as its core, constructs a highly efficient rock-breaking and hole-forming system. The connecting plate 103 (50mm thick, 800mm×630mm, epoxy anti-corrosion coating) is fixed to the slewing bearing 104 by 12 M35 bolts, and connected to the gear transmission mechanism by 28 M24 detachable screws (4 sets of holes). The self-rotating motor 102102 (GM1, 1225N·m, module 4 gear, efficiency ≥95%) drives the milling head 101 to rotate. 32 carbide milling teeth 1011 (8 simultaneously subjected to force, 550N) break 55MPa rock, producing debris ≤50mm.

[0145] In some embodiments, the revolution motor 105 (3000 N·m, C2.5 reducer, reduction ratio 5.5) drives the milling head 101 to revolve (8 r / min) through the revolution and slewing bearing 104 with 100 20 mm ball bearings, forming a 1.2-1.6 m circular hole with a verticality deviation of <0.5%.

[0146] In some embodiments, the rotary connector 106 (150 mm diameter, stainless steel, oil leakage rate <0.1 ml / h) supplies hydraulic oil through four channels at a pressure of 25 MPa, and the slag suction pipe 107 (100 mm diameter, Ra <1.4 μm, 200 mm length) extracts debris (0.5 m) under a negative pressure of 68.6 kPa. 3 / min), with a top rubber dust cover (110mm in diameter) to prevent foreign objects from entering.

[0147] In some other embodiments, the connecting plate 103 supports four servo motor lead screws (400mm stroke, ±1mm accuracy) to support an extension to a 2m aperture. The system achieves a rock-breaking speed of 0.5m / h and a slag discharge of 0.5m. 3 / min, noise ≤75dB, vibration ≤0.05mm, improved efficiency. Modular disassembly (milling head 101150kg×2, connecting plate 10360.8kg, etc., total weight 1.5t) is suitable for 2t cableway transportation, and the disassembly time is ≤15 minutes.

[0148] The publicly disclosed power head for milling and drilling achieves efficient rock breaking, precise hole formation, and negative pressure slag removal through precise coordination, meeting the construction needs of power transmission line towers in hard rock geology in mountainous areas.

[0149] This innovative approach introduces milling technology into the vertical drilling of borehole foundations for power transmission lines in hard rock geological conditions in mountainous areas, combined with negative pressure slag removal and modular structures.

[0150] These advantages enable the rotary / autorotating milling head to achieve efficient rock breaking, precise hole drilling, and convenient assembly in hard rock geological construction in mountainous areas, significantly improving construction efficiency and safety, and making it suitable for complex terrain and scenarios with high environmental protection requirements.

[0151] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions or improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A self-rotating milling head, characterized in that, include: The system comprises a self-rotating milling assembly, a revolution-slewing bearing, a revolution motor and reducer, two connecting plates, a rotary connector, and a slag suction pipe. Two sets of the self-rotating milling assemblies are mounted below the revolution-slewing bearing via connecting plates, rotating to break rock. The revolution-slewing bearing bears the axial, radial, and overturning forces of the two self-rotating milling assemblies. The revolution motor and reducer are fixed above the revolution-slewing bearing, driving the bearing to move the self-rotating milling assemblies circumferentially to form a circular hole wall. The rotary connector is coaxially arranged with the revolution-slewing bearing; its fixed outer sleeve is connected to a hydraulic pump station; the portion of the rotary connector's rotating shaft extending below the revolution-slewing bearing is connected to the self-rotating milling assembly via an oil pipe, driving the cutting disc and its point-impact cutter within the assembly to rotate. The slag suction pipe is connected to the revolution-slewing bearing, bearing the reaction force and transmitting downward pressure during rock breaking by the self-rotating milling head, while also serving as a negative pressure slag discharge channel.

2. The self-rotating milling power head according to claim 1, characterized in that, The two sets of self-rotating milling components are mounted on the revolution slewing bearing at an angle and cross each other via connecting plates. The tilt angles of the self-rotating milling components relative to the revolution slewing bearing are equal, and the self-rotating milling components are offset relative to the center of the revolution slewing bearing, ensuring that one set of self-rotating milling components can break the rock in the blind zone between the other set of self-rotating milling components when it revolves.

3. The self-rotating milling head according to claim 1, characterized in that, The self-rotating milling assembly includes: a self-rotating motor, a gear transmission mechanism, an internal milling head, an external milling head, and a housing. The self-rotating motor is installed on the input port of the gear transmission mechanism, and the two output ports of the gear transmission mechanism are located on both sides of the end of the housing, and the two output ports are on the same straight line. The internal milling head is installed on the output port of the gear transmission mechanism near the center of rotation, and the external milling head is installed on the output port of the gear transmission mechanism away from the center of rotation. The self-rotating motor transmits power to the cutting disc and the point impact cutter through the gear transmission mechanism, causing them to rotate and break the rock and soil they contact. The diameter of the excavated circular hole can be changed by changing the external milling head.

4. A self-rotating milling head according to claim 3, characterized in that, The internal and external milling heads of the self-rotating milling assembly are both composed of a cutting tooth drum, a cutting tooth disc, steel balls, a certain number of tool bases, and point impact tools. The cutting tooth drum consists of a cylindrical sleeve with a base at one end, a cutting tooth base, and cutting teeth. The bottom surface of the cutting tooth disc is installed on the unbase-free end of the cylindrical sleeve of the cutting tooth drum, forming a closed space with the cutting tooth drum. A large number of small-diameter steel balls are set in the closed space. The diameter of the steel balls should be less than 1 / 10 of the inner diameter of the cutting tooth disc. The total number of steel balls should fill between 1 / 3 and 1 / 2 of the closed space to increase the cutting force and reduce the vibration caused by springback. The cutting tooth drum and the cutting tooth disc are fixed on the shaft of the gear transmission mechanism of the self-rotating milling assembly.

5. A self-rotating milling power head according to claim 4, characterized in that, The tool base is welded to the cutting tooth drum and the cutting tooth disc, and the point impact tool equipped with a carbide cutting tip is mounted on the tool base by a retaining ring; To achieve better rock-breaking results, the point-impact cutting tools are arranged in a regular pattern of multiple spiral lines on the cutting drum; the number N of cutting tools on the circumference of a single spiral line on the cutting drum should not be less than: N≥0.4πDP Where N is the number of cutters on the circumference of a single-row helical line; D is the outer diameter of the cutting drum, in meters; and P is the uniaxial saturated compressive strength of the rock being cut, in MPa. The spacing L between the upward-axis cutting tools of the cutting drum should not exceed: L≤400d / P Where L is the axial spacing between the cutting tools, m; d is the diameter of the carbide tip holder on the cutting tool, m; P is the uniaxial saturated compressive strength of the rock being tested, MPa; The number of cutting tools on the cutting tooth disc is equal to the aforementioned N, and they are installed at equal intervals on the circumference of the cutting tooth disc. The diameter of the drilled pile hole can be changed by replacing the cutting tooth drum of different lengths on the external milling head.

6. The self-rotating milling power head according to claim 1, characterized in that, The revolution-slewing bearing consists of an outer ring pinion, an inner ring gear, a fixed-end upper mounting plate, a rotating-end lower mounting plate, and peripheral guard plates. The outer ring pinion is connected to the output shaft of the revolution motor and reducer mounted on the fixed-end upper mounting plate. Driven by the outer ring pinion, it drives the inner ring gear and the rotating-end lower mounting plate fixed to it to rotate. At the same time, it drives the connecting plate on the rotating-end lower mounting plate to revolve with the self-rotating milling assembly to form a circular hole wall.

7. A self-rotating milling head according to claim 6, characterized in that, The rotary connector includes: a fixed outer sleeve, a rotating shaft, a sealing assembly, a bearing, and a fixed seat. The fixed outer sleeve and the rotating shaft have four corresponding channels: two oil inlets, one oil return, and one oil discharge. These channels are used to stably supply oil to the self-rotating milling assembly during revolution. The fixed outer sleeve of the rotary connector is connected to its fixed seat. The fixed seat is fixedly connected to the mounting plate on the fixed end of the slewing bearing. The rotating shaft is fixedly connected to the mounting plate on the rotating end of the slewing bearing. It can rotate with the revolution to stably supply oil to the self-rotating milling assembly. The two oil inlets of the rotating shaft are respectively connected to the hydraulic oil input port of the self-rotating milling assembly. The oil return end of the self-rotating milling assembly is merged into one channel and connected to the oil return channel of the rotating shaft. The oil discharge end of the self-rotating milling assembly is merged into one channel and connected to the oil discharge channel of the rotating shaft.

8. A self-rotating milling head according to claim 1, characterized in that, The slag suction pipe serves as both a torque transmission channel and a slag discharge channel. It is inserted into the slewing bearing. The portion of the slag suction pipe extending above the slewing bearing is connected to an external material extraction device. The portion of the slag suction pipe extending below the slewing bearing is located between the rotation ranges of the two self-rotating milling components, and its height above the lower position of the rotation range of the two self-rotating milling components is higher than the lowest position of the rotation range of the two self-rotating milling components.

9. A self-rotating milling power head according to claim 8, characterized in that, The rotary connector has a through hole in the center, and the slag suction pipe is installed in the central circular hole of the rotary connector, so that the rotary connector, slag suction pipe and revolution slewing bearing are coaxially arranged.

10. A self-rotating milling power head according to claim 8, characterized in that, The slag suction pipe consists of a circular guide tube, a drill rod connecting plate, and a connecting support. The upper end of the circular guide tube is welded with a flange for connecting the drill rod and for negative pressure extraction of slag. The middle section of the circular guide tube passes through the hole in the middle of the drill rod connecting plate and is welded to the drill rod connecting plate. The drill rod connecting plate is connected to the mounting plate on the fixed end of the revolution slewing bearing through the connecting support. The lower section of the circular guide tube passes through the central circular hole of the rotating shaft of the rotary connector and extends into the inner milling head of the self-rotating milling assembly.

11. A self-rotating milling power head according to claim 10, characterized in that, The bottom of the circular guide tube of the slag suction pipe has an arc-shaped cover. The arc shape of this cover is parallel to the line connecting the inner milling head cutter of the self-rotating milling assembly. This cover collects the debris that moves due to inertia as the inner milling head cutter rotates into the circular guide tube. The distance between the bottom of the arc-shaped cover and the line connecting the inner milling head cutter is controlled to be less than 1 / 3 of the inner diameter of the circular guide tube. This reduces the probability of debris with a diameter greater than 1 / 3 of the inner diameter of the circular guide tube entering the circular guide tube and prevents blockage. The circular guide tube above the arc-shaped cover is arranged according to a cylindrical spiral pattern. The air guide holes, approximately 1 cm in diameter, are distributed at a 60-degree angle around the circumference. The spiral line is 1.5 times longer than the inner diameter of the circular conduit, utilizing the Venturi effect to create negative pressure at the convergence point. This provides a significant acceleration to the crushed stone and soil, creating a spiral motion. The soil moves vertically within the pipe with its longest diameter aligned with the airflow direction, reducing the probability of blockage. The bottom of the arc-shaped cover and the circular conduit are coated with a wear-resistant, non-stick polytetrafluoroethylene coating to prevent wet materials from adhering to the pipe wall.

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