Cutting arm of a mining machine applicable to thin ore seam mining

Abstract

The present invention relates to a cutting arm of a mining machine applicable to thin ore seam mining, which comprises a boom and a cutting motor and a transmission system installed in the inner cavity of the boom. The transmission system includes a high-speed planetary mechanism, a front fixed-axis reduction transmission mechanism and a rear fixed-axis reduction transmission mechanism. The final-stage transmission of the rear fixed-axis reduction transmission mechanism adopts a gear shaft. The high-speed planetary mechanism and the front fixed-axis reduction transmission mechanism are located in the proximal section of the boom and are connected to the output of the cutting motor. The gear shaft is rotationally supported on the drum installation part of the boom. The gear end of the gear shaft and other levels of transmission of the rear fixed-axis reduction transmission mechanism are located in the middle and far sections of the straight arm part. The non-gear end of the gear shaft is coaxially fixedly connected with a small-diameter drum. The distal end of the boom is set as a local thin strip structure with the upper and lower thicknesses becoming thinner closer to the distal end. The present invention can enable the mining machine to maintain sufficient down-cutting amount and roof-picking amount, and is applicable to the mining of ore and rock working faces with a large mining range and complex geological conditions.

Description

Technical Field

[0001] The invention relates to a cutting arm of a mining machine suitable for mining thin ore layers, and is particularly suitable for mining thin ore layers or thicker ore layers with a large mining range and complex geological conditions at ore rock working faces, belonging to the technical field of underground mining machinery. Background Art

[0002] For the mining of thin bauxite ore layers, the geological conditions are often complex. Not only do soil-like ore layers coexist with rock-like waste materials, but the thickness of the ore layers varies greatly. Therefore, not only a large cutting force is required, but also the mining machine needs to be short and adaptable to the mining of thick ore layers. According to conventional design rules, a larger cutting force usually means that a larger power cutting motor, a thicker cutting arm with thicker upper and lower arms, and a larger diameter roller are required. A short mining machine requires the cutting arm to have sufficient down-cutting amount relative to the conveying device and sufficient top-lifting amount relative to the support top beam. However, a thicker cutting arm often leads to insufficient down-cutting amount and top-lifting amount, which seriously affects mining. Therefore, it is necessary to solve the above-mentioned structural layout problems of heavy-duty, wide-mining-height thin-layer mining machines. Summary of the invention

[0003] The present invention aims to provide a cutting arm for a mining machine suitable for mining thin ore layers, which can provide a large cutting force while enabling the mining machine to maintain sufficient down-cutting and top-lifting amounts, so that a short-body, high-power mining machine is suitable for mining in ore and rock working faces with a large mining range and complex geological conditions.

[0004] The main technical solutions of the present invention are:

[0005] A mining machine cutting arm suitable for thin-layer mining, comprising an arm, a cutting motor, a transmission system, a clutch mechanism and a small-diameter roller. The proximal end of the arm is provided with a mounting interface structure for connecting to the mining machine body. When the arm is mounted on the mining machine body, the distal end of the arm is cantilevered and away from the body. The arm comprises a straight arm portion and a motor mounting portion protruding rearward from the proximal end of the straight arm portion and a roller mounting portion protruding forward from the distal end of the straight arm portion. The cutting motor, transmission system and clutch mechanism are all arranged in the inner cavity of the arm, and the cutting motor is located at the motor mounting portion. The transmission system comprises a high-speed planetary mechanism, a front fixed-axis reduction transmission mechanism and a rear fixed-axis reduction transmission mechanism connected in sequence according to the transmission direction. The final-stage transmission of the rear fixed-axis reduction transmission mechanism adopts a gear shaft. The star mechanism and the front fixed-axis reduction transmission mechanism are arranged at the proximal section of the straight arm portion, the gear shaft is rotatably supported on the roller mounting portion, the gear end of the gear shaft and the other levels of transmission of the rear fixed-axis reduction transmission mechanism are arranged at the middle and distal sections of the straight arm portion, the small-diameter roller is sleeved outside the roller mounting portion and is coaxially fixedly connected to the non-gear end of the gear shaft, the high-speed planetary mechanism is coaxially arranged in front of the cutting motor, the input end of the high-speed planetary mechanism is connected or disconnected from the output end of the cutting motor through the clutch mechanism, the top surface and the bottom surface of the distal end of the straight arm portion are respectively provided with an upper inclined plane and a lower inclined plane, and the inclination direction is a direction in which the upper and lower thicknesses of the straight arm portion become thinner as it approaches the distal end, so that the distal end of the straight arm portion forms a local thin strip structure with thinner upper and lower thicknesses.

[0006] The high-speed planetary mechanism includes a high-speed sun gear, a high-speed planetary gear, a high-speed planetary carrier and a high-speed inner gear ring. The high-speed inner gear ring is circumferentially fixed on the arm frame. The high-speed sun gear is the input end of the first-stage transmission.

[0007] The front fixed shaft reduction transmission mechanism includes a front fixed shaft reduction pinion, a front fixed shaft reduction intermediate gear and a front fixed shaft reduction gear which are connected in sequence with external meshing transmission. The front fixed shaft reduction pinion is rotatably supported on the arm bracket, and the high-speed planetary carrier and the front fixed shaft reduction pinion are respectively sleeved on a high-speed connecting shaft from both ends and are coaxially splined with the high-speed connecting shaft.

[0008] The rear fixed shaft reduction transmission mechanism also includes a rear fixed shaft reduction front gear and a rear fixed shaft reduction intermediate gear. The rear fixed shaft reduction front gear, the rear fixed shaft reduction intermediate gear and the gear shaft are connected in an external meshing transmission manner in sequence.

[0009] The cutting motor is preferably a multi-pole motor, and the number of poles may be 6, 8, 10 or 12.

[0010] The boom is of a split structure, including a split boom and a split transition seat. The mounting interface structure is arranged on the split transition seat, and the split boom and the split transition seat are tightly connected by a connecting piece.

[0011] On the surface of the split transition seat that fits with the split boom, a plurality of transition seat pin hole groups are dispersedly arranged. Each transition seat pin hole group includes a front transition seat pin hole and a rear transition seat pin hole. On the surface of the split boom that fits with the split transition seat, a plurality of split boom pin hole groups corresponding one by one to the transition seat pin hole groups are dispersedly arranged. Each split boom pin hole group includes a front split boom pin hole and a rear split boom pin hole. The diameters of all the pin holes are equal. The split transition seat and the split boom are positioned in the front-back and up-down directions by a connecting pin that simultaneously passes through one pin hole of each transition seat pin hole group and one pin hole of the corresponding split boom pin hole group. The split transition seat and the split boom are fastened by bolts and nuts.

[0012] The front transition seat pin hole and the front split boom pin hole are simultaneously matched with a connecting pin to achieve positioning, or the rear transition seat pin hole and the rear split boom pin hole are simultaneously matched with a connecting pin to achieve positioning. When the center distance between the front and rear transition seat pin holes is greater than the center distance between the front and rear split boom pin holes, the front end face of the split boom is flush with the split transition seat when the rear transition seat pin hole and the rear split boom pin hole are simultaneously matched with a connecting pin. When the center distance between the front and rear transition seat pin holes is less than the center distance between the front and rear split boom pin holes, the front end face of the split boom is flush with the split transition seat when the front transition seat pin hole and the front split boom pin hole are simultaneously matched with a connecting pin.

[0013] The split transition seat is also provided with a plurality of bolt holes, which correspond one by one to the transition seat pin hole groups. The split boom is provided with a plurality of waist-shaped grooves and a plurality of nut grooves, which correspond one by one to the bolt holes. The split transition seat and the split boom are tightly connected by passing bolts through the bolt holes and the corresponding waist-shaped grooves and locking with square nuts in the nut grooves. The difference between the center distance of the front and rear transition seat pin holes and the center distance of the front and rear split boom pin holes is not greater than the difference between the length and width of the waist-shaped groove.

[0014] The beneficial effects of the present invention are:

[0015] On the top surface and the bottom surface of the distal end of the straight arm part of the boom, an upper inclined plane and a lower inclined plane are respectively provided, so that the upper and lower thicknesses of the straight arm part are smaller closer to the distal end, and a local thin strip structure with smaller upper and lower thicknesses is formed at the distal end of the boom, which provides a guarantee for the small-diameter drum to have a large roof lifting amount and a large undercut amount relative to the front beam of the support and the top surface of the conveyor scraper plate respectively.

[0016] The front section of the transmission system of the present invention is provided with a planetary mechanism and a front fixed-axis reduction transmission mechanism, and the rear section is provided with a rear fixed-axis reduction transmission mechanism for multi-stage reduction, providing conditions for reducing the size of the final-stage transmission, especially the radial size. Therefore, the diameter of the drum mounting part can be very small, and thus a drum with a very small diameter can be used, which can not only adapt to a wider mining height range but also provide a fundamental guarantee for obtaining a larger roof cutting amount and a larger undercut amount of the drum relative to the support and the conveyor respectively.

[0017] The present invention adopts a multi-pole cutting motor, and in combination with the above-mentioned transmission system, the structural layout of the cutting arm can be made more flexible.

[0018] Since the distal end of the boom adopts a local thin strip structure, the ore is more likely to cross the boom from the top and enter the conveyor trough, improving the loading effect of the straight boom structure with a small-diameter drum.

[0019] Since the split boom has the selectivity of different front and rear installation positions in the horizontal direction relative to the split transition frame, a larger safety gap between the boom and the conveyor trough can be provided, facilitating corresponding adjustment according to the actual conditions of the working face, thereby improving the adaptability. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is the front view (right cutting arm) of an embodiment of the present invention;

[0021] Figure 2 is Figure 1 the horizontal sectional view of

[0022] Figure 3 is Figure 1 the lower swing state diagram of the embodiment shown;

[0023] Figure 4 is Figure 1 the upper swing state diagram of the embodiment shown;

[0024] Figure 5 is the partial sectional view of the front fixed-axis reduction transmission mechanism;

[0025] Figure 6 is the partial sectional view of the high-speed planetary mechanism;

[0026] Figure 7 is the partial sectional view of the rear fixed-axis reduction transmission mechanism;

[0027] Figure 8 is the front view (right cutting arm) of the split boom of the present invention;

[0028] Figure 9 is the front view (right cutting arm) of the split transition frame of the present invention;

[0029] Figure 10This is a sectional view of the extreme positions of the relative support and conveyor of the present invention;

[0030] Figure 11 This is the front view of a mining machine equipped with the cutting arm of the present invention;

[0031] Figure 12 This is the top view of a mining machine equipped with the cutting arm of the present invention;

[0032] Figure 13 This is another schematic diagram of the connection position of the boom of the present invention.

[0033] Reference numerals:

[0034] 1. Boom; 11. Split transition seat; 111. Front pin hole of the transition seat; 112. Rear pin hole of the transition seat; 113. Bolt hole; 12. Split arm; 121. Upper inclined plane and lower inclined plane; 125. Drum mounting part; 126. Waist-shaped groove; 127. Nut groove; 128. Front pin hole of the split arm; 129. Rear pin hole of the split arm; 13. Connecting piece; 14. Connecting pin;

[0035] 21. High-speed planetary mechanism; 211. High-speed sun gear; 212. High-speed planetary gear; 213. High-speed internal gear ring; 2131. Card slot; 214. High-speed bearing; 215. High-speed pin; 216. High-speed planet carrier; 217. High-speed connecting shaft; 22. Front fixed-axis reduction drive mechanism; 221. Front fixed-axis reduction pinion; 222. Front fixed-axis reduction intermediate gear; 223. Front fixed-axis reduction large gear; 224. Front fixed-axis reduction bearing seat; 23. Rear fixed-axis reduction drive mechanism; 231. Rear fixed-axis reduction front gear; 232. Rear fixed-axis reduction intermediate gear; 233. Gear shaft; 234. Drum connecting sleeve;

[0036] 3. Cutting motor;

[0037] 4. Clutch mechanism; 41. Torque shaft;

[0038] 5. Small-diameter drum;

[0039] 7. Machine body; 71. Cutting arm connecting piece; 72. Cutting arm oil cylinder;

[0040] 8. Support; 81. Top surface of the support; 82. Bottom surface of the front beam of the support;

[0041] 9. Conveyor; 91. Bottom surface of the conveyor; 92. Top surface of the scraper of the conveyor;

[0042] A. Undercutting amount; B. Roof cutting amount; C. Boom offset amount. Detailed implementation manners

[0043] The present invention discloses a cutting arm of a mining machine suitable for thin seam mining, asFigure 1-13 As shown in the figure, it includes a boom 1, a cutting motor 3, a transmission system, a clutch mechanism 4, and a small-diameter drum 5. The boom 1 is connected to the mining machine body 7 through a cutting boom connecting piece 71 and a cutting boom oil cylinder 72. In this article, each part of the boom is named according to the distance from the boom to the mining machine body 7 when the boom is installed on the mining machine body. The proximal end of the boom is provided with an installation interface structure for connecting to the mining machine body, such as a connecting ear seat. The distal end of the boom extends and is away from the body. The boom includes a straight arm portion, a motor mounting portion protruding backward from the proximal end of the straight arm portion, and a drum mounting portion 125 protruding forward from the distal end of the straight arm portion. The cutting motor, the transmission system, and the clutch mechanism are all arranged in the inner cavity of the boom. The cutting motor 3 is located in the motor mounting portion. The transmission system includes a high-speed planetary mechanism 21, a front fixed-axis reduction transmission mechanism 22, and a rear fixed-axis reduction transmission mechanism 23 connected in sequence according to the transmission direction. The final-stage transmission of the rear fixed-axis reduction transmission mechanism uses a gear shaft 233. The high-speed planetary mechanism and the front fixed-axis reduction transmission mechanism are arranged in the proximal section of the straight arm portion. The gear shaft is rotationally supported by the drum mounting portion. The end where the gear of the gear shaft is located, that is, the rear end, and other stages of the rear fixed-axis reduction transmission mechanism are arranged in the middle and far sections of the straight arm portion. The small-diameter drum 5 is sleeved outside the drum mounting portion and is coaxially fixedly connected to the non-gear end, that is, the front end, of the gear shaft through a drum connecting sleeve 234. The drum connecting sleeve 234 is located in front of the gear shaft. The high-speed planetary mechanism is coaxially arranged in front of the cutting motor. The input end of the high-speed planetary mechanism is connected or disconnected from the output end of the cutting motor through the clutch mechanism. The top surface and the bottom surface of the distal end of the straight arm portion are respectively provided with an upper inclined plane and a lower inclined plane 121 (the inclination here can be relative to the parallel top surface and bottom surface of the proximal section of the straight arm portion, or relative to the plane where the axes of each stage of the transmission system are located). The inclination direction is such that the closer the straight arm portion is to the distal end, the thinner the thickness from top to bottom, so that the distal end of the straight arm portion forms a locally thin strip-like structure with a thinner thickness from top to bottom. The cutting motor 3 transmits power through the clutch mechanism 4 and is decelerated by the transmission system and then transmitted to the small-diameter drum 5 for output. In the mining of thin coal seams, when the straight arm portion is in the extreme upper swing and lower swing states, the upper inclined plane and the lower inclined plane can respectively reach positions close to parallel with the bottom surface 82 of the front beam of the support 8 and the top surface 92 of the conveyor scraper of the conveyor 9, thereby respectively obtaining the maximum roof cutting amount B (the distance from the highest point of the drum to the top surface of the support 8) and the undercutting amount A (the distance from the lowest point of the drum to the bottom surface of the conveyor 9) of the small-diameter drum 5.

[0044] Since the first-stage drive of the transmission system adopts a planetary mechanism, not only is its own volume small and weight light, but also due to its large bearing capacity and large speed ratio, the sizes of other downstream drives and the drum can be greatly reduced without changing the power output of the cutting arm. Therefore, it is beneficial to reduce the overall size of the boom and further reduce the size of the distal end of the boom compared to the proximal end. Thus, the mining machine can provide a large cutting force while maintaining sufficient down-cutting and roof-cutting amounts, making the corresponding mining machine suitable for the mining of ore-rock working faces with a large mining height range and complex geological conditions.

[0045] Since the final-stage drive of the transmission system adopts a gear shaft output structure with a small diameter, the diameter of the drum mounting part 125 of the boom is also small, and a drum with a very small diameter can be matched. At the same time, a local thin strip structure with a relatively thin upper and lower thickness is provided at the distal end of the straight boom part, so that the cutting arm of the present invention can not only be matched with a small-diameter drum, but also the small-diameter drum can have a large roof-cutting amount and a large down-cutting amount relative to the support and the conveyor respectively; it not only ensures the mining of high-grade thin ore seams, but also improves the adaptability to the mining of complex working faces.

[0046] Due to the provision of the local thin strip structure, ore is more likely to cross the boom from the top and enter the conveyor trough, thereby improving the loading effect of the straight boom structure under the small-diameter drum.

[0047] The high-speed planetary mechanism 21 includes a high-speed sun gear 211, high-speed planet gears 212, a high-speed planet carrier 216, and a high-speed internal gear ring 213. The high-speed internal gear ring can be circumferentially positioned with respect to the boom by installing a plurality of high-speed pins 215. In this embodiment, one end face of the high-speed internal gear ring is in contact with an inner surface of the boom, and the high-speed pins 215 are arranged at the contact position between the two, and the axes extend along the axial direction of the high-speed internal gear ring. The high-speed sun gear is the input end of the first-stage drive. Power is transmitted to the high-speed sun gear 211 through the clutch mechanism 4. The high-speed sun gear 211 transmits power to the high-speed planet carrier 216 by meshing with the high-speed planet gears 212. The clutch mechanism transmits power to the high-speed sun gear through the positioning and pushing / pulling connection between the torque shaft 41 at its front end and the high-speed sun gear 211.

[0048] The front fixed-axis reduction drive mechanism 22 may include a front fixed-axis reduction pinion 221, a front fixed-axis reduction intermediate gear 222, and a front fixed-axis reduction large gear 223 that are sequentially externally meshed and drivingly connected. The front fixed-axis reduction pinion is rotatably supported on a front fixed-axis reduction bearing seat 224, and the front fixed-axis reduction bearing seat is fixedly installed in the inner cavity of the boom. The high-speed planetary carrier and the front fixed-axis reduction pinion are respectively sleeved on a high-speed connection shaft 217 from the rear end and the front end, and are coaxially splined to the high-speed connection shaft. The power output by the high-speed planetary carrier is transmitted to the front fixed-axis reduction pinion through the high-speed connection shaft. The high-speed internal gear ring 213 and the front fixed-axis reduction bearing seat 224 are axially spaced apart by providing a card slot 2131. The high-speed planetary carrier is rotatably supported inside the high-speed internal gear ring by a high-speed bearing 214.

[0049] The rear fixed-axis reduction drive mechanism 23 includes a rear fixed-axis reduction front gear 231, a rear fixed-axis reduction intermediate gear 232, and the gear shaft 233 that are sequentially externally meshed and drivingly connected. There may be multiple rear fixed-axis reduction intermediate gears.

[0050] The cutting motor preferably uses a multi-pole motor, and the number of poles can be 6, 8, 10, or 12.

[0051] The boom adopts a split structure, including a split boom 12 and a split transition seat 11. The installation interface structure is arranged on the split transition seat. The split boom and the split transition seat can be positioned by a connecting pin 14 and connected and fastened by a connecting member 13 such as a bolt and a gasket. For a double-drum mining machine, when the boom adopts a split structure, the split booms of the left and right cutting arms are symmetrical left and right, so that the split boom can be interchanged in the left and right cutting arms, making production simpler.

[0052] On the surface of the split transition seat that fits with the split boom, a plurality of transition seat pin hole groups are dispersedly provided, preferably four groups in the front, rear, upper, and lower directions. Each transition seat pin hole group includes a transition seat front pin hole 111 and a transition seat rear pin hole 112. On the surface of the split boom that fits with the split transition seat, a plurality of split boom pin hole groups corresponding one-to-one to the transition seat pin hole groups are dispersedly provided. Each split boom pin hole group includes a split boom front pin hole 128 and a split boom rear pin hole 129. The diameters of all the pin holes are equal. The split transition seat and the split boom are positioned in the front, rear, upper, and lower directions by a connecting pin 14 that simultaneously fits into a pin hole of each transition seat pin hole group and a corresponding pin hole of the split boom pin hole group. The split transition seat and the split boom are fastened by bolts and nuts. The split boom can have multiple front and rear installation positions relative to the split transition frame, which can provide a larger safety clearance between the boom and the conveyor trough side, facilitating corresponding adjustments according to the actual conditions of the working face, thereby improving adaptability.

[0053] Further, the front pin hole of the transition seat and the front pin hole of the split arm are simultaneously engaged with a connecting pin 14 for positioning, or the rear pin hole of the transition seat and the rear pin hole of the split arm are simultaneously engaged with a connecting pin 14 for positioning. In this case, it is only necessary that the diameters of the front pin hole of the transition seat and the front pin hole of the split arm are equal, and the diameters of the rear pin hole of the transition seat and the rear pin hole of the split arm are equal. When the center distance between the front and rear pin holes of the transition seat is greater than the center distance between the front and rear pin holes of the split arm, the front end face of the split arm and the split transition seat are preferably flush when the rear pin hole of the transition seat and the rear pin hole of the split arm are simultaneously engaged with a connecting pin (see Figure 2 ); when the center distance between the front and rear pin holes of the transition seat is less than the center distance between the front and rear pin holes of the split arm, the front end face of the split arm and the split transition seat are preferably flush when the front pin hole of the transition seat and the front pin hole of the split arm are simultaneously engaged with a connecting pin.

[0054] More preferably, a plurality of bolt holes 113 are provided on the split transition seat, and the bolt holes correspond to the transition seat pin hole group one by one. A plurality of waist-shaped grooves 126 and a plurality of nut grooves 127 are provided on the split arm, and the waist-shaped grooves and the nut grooves correspond to the bolt holes one by one. The split transition seat and the split arm are firmly connected by passing bolts through the bolt holes and the corresponding waist-shaped grooves and locking with square nuts in the nut grooves. The difference between the center distance of the front and rear pin holes of the transition seat and the center distance of the front and rear pin holes of the split arm should not be greater than the difference between the length and the width of the waist-shaped groove.

[0055] In this embodiment, the center distance between the front and rear pin holes of the transition seat is greater than the center distance between the front and rear pin holes of the split arm. When the connecting pin 14 is arranged in the rear pin hole of the transition seat and the rear pin hole of the split arm, the front end face of the split arm is flush with the split transition seat (see Figure 2 ). At this time, the connecting member 13 is located at a position in the front of the waist-shaped groove. When the connecting pin 14 is arranged in the front pin hole of the transition seat and the front pin hole of the split arm, the split arm is offset forward by a certain distance relative to the split transition seat, that is, the boom offset C (see Figure 13 ). At this time, the connecting member 13 is located at a position in the rear of the waist-shaped groove. The boom offset C can provide a larger safety clearance between the boom and the conveyor trough side. The boom offset C is equal to the difference between the center distance of the front and rear pin holes of the transition seat and the center distance of the front and rear pin holes of the split arm.

Claims

1. A cutting arm for a mining machine suitable for mining thin ore layers. Features: It includes a boom, a cutting motor, a transmission system, a clutch mechanism and a small-diameter roller. The proximal end of the boom is provided with a mounting interface structure for connecting to the body of the mining machine. When the boom is installed on the body of the mining machine, the distal end of the boom is cantilevered and away from the body. The boom includes a straight arm portion and a motor mounting portion protruding rearward from the proximal end of the straight arm portion and a roller mounting portion protruding forward from the distal end of the straight arm portion. The cutting motor, transmission system and clutch mechanism are all arranged in the inner cavity of the boom. The cutting motor is located at the motor mounting portion. The transmission system includes a high-speed planetary mechanism, a front fixed-axis reduction transmission mechanism and a rear fixed-axis reduction transmission mechanism connected in sequence according to the transmission direction. The final-stage transmission of the rear fixed-axis reduction transmission mechanism adopts a gear shaft. The high-speed planetary mechanism and the front fixed-axis reduction transmission mechanism are connected in sequence according to the transmission direction. The transmission mechanism is arranged at the proximal section of the straight arm portion, the gear shaft is rotatably supported on the roller mounting portion, the gear end of the gear shaft and other levels of transmission of the rear fixed-axis reduction transmission mechanism are arranged at the middle and distal sections of the straight arm portion, the small-diameter roller is sleeved outside the roller mounting portion and is coaxially fixedly connected to the non-gear end of the gear shaft, the high-speed planetary mechanism is coaxially arranged in front of the cutting motor, and the input end of the high-speed planetary mechanism is connected or disconnected from the output end of the cutting motor through the clutch mechanism, the top surface and the bottom surface of the distal end of the straight arm portion are respectively provided with an upper inclined plane and a lower inclined plane, and the inclination direction is a direction in which the upper and lower thicknesses of the straight arm portion become thinner as it approaches the distal end, so that the distal end of the straight arm portion forms a local thin strip structure with thinner upper and lower thicknesses.

2. The cutting arm of a mining machine suitable for thin-layer mining as claimed in claim 1, Features: The high-speed planetary mechanism comprises a high-speed sun gear, a high-speed planetary gear, a high-speed planetary carrier and a high-speed inner gear ring. The high-speed inner gear ring is circumferentially fixed on the arm frame. The high-speed sun gear is the input end of the first-stage transmission.

3. The cutting arm of a mining machine suitable for thin-layer mining as claimed in claim 2, Features: The front fixed shaft reduction transmission mechanism includes a front fixed shaft reduction pinion, a front fixed shaft reduction intermediate gear and a front fixed shaft reduction gear which are connected in sequence with external meshing transmission. The front fixed shaft reduction pinion is rotatably supported on the arm bracket, and the high-speed planetary carrier and the front fixed shaft reduction pinion are respectively sleeved on a high-speed connecting shaft from both ends and are coaxially splined with the high-speed connecting shaft.

4. The cutting arm of a mining machine suitable for thin-layer mining as claimed in claim 3, Features: The rear fixed shaft reduction transmission mechanism also includes a rear fixed shaft reduction front gear and a rear fixed shaft reduction intermediate gear. The rear fixed shaft reduction front gear, the rear fixed shaft reduction intermediate gear and the gear shaft are connected in an external meshing transmission manner in sequence.

5. A cutting arm for a mining machine suitable for thin-layer mining as claimed in claim 1, 2, 3 or 4, Features: The cutting motor is a multi-pole motor with 6, 8, 10 or 12 poles.

6. A cutting arm for a mining machine suitable for thin-layer mining as claimed in claim 1, 2, 3 or 4, It is characterized in that: The boom is of a split structure, including a split arm and a split transition seat. The installation interface structure is arranged on the split transition seat, and the split arm and the split transition seat are tightly connected through a connecting piece.

7. The cutting boom of a mining machine applicable to thin ore seam mining according to claim 6, It is characterized in that: A plurality of transition seat pin hole groups are dispersedly arranged on the surface of the split transition seat that fits with the split arm. Each transition seat pin hole group includes a front transition seat pin hole and a rear transition seat pin hole. A plurality of split arm pin hole groups corresponding to the transition seat pin hole groups one by one are dispersedly arranged on the surface of the split arm that fits with the split transition seat. Each split arm pin hole group includes a front split arm pin hole and a rear split arm pin hole. The diameters of all the pin holes are equal. The split transition seat and the split arm are positioned in the front-back and up-down directions by a connecting pin that simultaneously passes through one pin hole of each transition seat pin hole group and one pin hole of the corresponding split arm pin hole group. The split transition seat and the split arm are fastened by bolts and nuts.

8. The cutting boom of a mining machine applicable to thin ore seam mining according to claim 7, It is characterized in that: The front transition seat pin hole and the front split arm pin hole are simultaneously fitted with a connecting pin to achieve positioning, or the rear transition seat pin hole and the rear split arm pin hole are simultaneously fitted with a connecting pin to achieve positioning. When the center distance between the front and rear transition seat pin holes is greater than the center distance between the front and rear split arm pin holes, the front end face of the split arm is flush with the split transition seat when the rear transition seat pin hole and the rear split arm pin hole are simultaneously fitted with a connecting pin. When the center distance between the front and rear transition seat pin holes is less than the center distance between the front and rear split arm pin holes, the front end face of the split arm is flush with the split transition seat when the front transition seat pin hole and the front split arm pin hole are simultaneously fitted with a connecting pin.

9. The cutting boom of a mining machine applicable to thin ore seam mining according to claim 8, It is characterized in that: A plurality of bolt holes are arranged on the split transition seat, and the bolt holes correspond to the transition seat pin hole groups one by one. A plurality of waist-shaped grooves and a plurality of nut grooves are arranged on the split arm, and the waist-shaped grooves and the nut grooves correspond to the bolt holes one by one. The split transition seat and the split arm are tightly connected by passing bolts through the bolt holes and the corresponding waist-shaped grooves and locking with square nuts in the nut grooves. The difference between the center distance of the front and rear transition seat pin holes and the center distance of the front and rear split arm pin holes is not greater than the difference between the length and the width of the waist-shaped groove.

10. The cutting boom of a mining machine applicable to thin ore seam mining according to claim 5, It is characterized in that: The boom is of a split structure, including a split arm and a split transition seat. The installation interface structure is arranged on the split transition seat, and the split arm and the split transition seat are tightly connected through a connecting piece.

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