Semi-suspension cutting device and thin seam coal mining machine

Abstract

The present application relates to a kind of semi-suspended cutting device and thin coal seam shearer, the semi-suspended cutting device includes shell and cutting motor and cutting transmission system installed in shell, cutting transmission system includes first, second, third straight-tooth transmission mechanism and planetary reduction mechanism connected in sequence, planetary reduction mechanism and first straight-tooth transmission mechanism are located at the forefront in front-back direction, third straight-tooth transmission mechanism is followed, and second straight-tooth transmission mechanism is last, cutting motor is arranged in the goaf side of shell, rear of cutting motor and motor barrel where it is located are suspended and beyond second straight-tooth transmission mechanism backwards;The left and right cutting device of the thin coal seam shearer is using the semi-suspended cutting device.The present application can solve the contradiction between the height of thin coal seam shearer machine surface, installed power, coal space and the stability of whole machine, adaptability, and the problem of cutting motor maintenance inconvenience, high cost of damage replacement.

Description

Technical Field

[0001] This invention relates to a cutting device suitable for thin coal seam mining machines and a mining machine using the cutting device, belonging to the field of coal mining machinery technology. Background Technology

[0002] In conventional transversely arranged coal mining machine cutting devices (transverse arrangement of the coal mining machine cutting device refers to the arrangement of the cutting motor axis perpendicular to the direction of travel of the coal mining machine, i.e., the working face direction), since the cutting motor is located above the two sides of the scraper conveyor, the cutting motor will swing up and down with the cutting device during coal cutting. When swinging upward, it will affect the safety clearance with the hydraulic support, and correspondingly increase the machine face height. When swinging downward, it will reduce the coal passage space. Moreover, the larger the motor power, the larger its diameter. The size of the cutting motor directly affects the machine face height and the coal passage space. However, thin coal seam mining machines require a lower machine face height and a certain coal passage space. Therefore, the improvement of the cutting power of thin coal seam mining machines is limited.

[0003] Some industry professionals have proposed arranging the cutting motor in the opposite direction on the coal face side, on the same side as the planetary mechanism and conveyor, utilizing the space on the coal face side to avoid the cutting motor's impact on the machine face height and coal passage space. However, this fully suspended arrangement of the coal mining machine also has two major drawbacks: Firstly, because the cutting motor is arranged in the opposite direction on the coal face side, the motor needs to be disassembled and installed from the coal face side. The maintenance space required for disassembling and installing the motor exceeds the drum, thus encountering solid coal face that the drum has not yet mined. During maintenance, a dedicated maintenance space must be mined on the coal face side, and the working space in thin coal seam working faces is narrow, making maintenance and replacement very inconvenient. Secondly, because all the main structural parts of the machine are suspended on the coal face side, the center of gravity of the whole machine is off-center from the support slipper, which leads to a deterioration of the stress condition of the coal mining machine during operation, making it difficult to adapt to the undulation of the floor, reducing the operating stability and adaptability of the coal mining machine. Summary of the Invention

[0004] The present invention aims to provide a semi-suspended cutting device and a thin coal seam mining machine, which can solve the contradiction between the machine face height, installed power, coal passage space and overall stability and adaptability of the thin coal seam mining machine, as well as the problems of inconvenient maintenance and high cost of replacement of the cutting motor.

[0005] The main technical solutions of this invention are as follows:

[0006] A semi-suspended cutting device includes a housing and a cutting motor and a cutting transmission system installed within the housing. The cutting transmission system includes a first-stage spur gear transmission mechanism, a second-stage spur gear transmission mechanism, a third-stage spur gear transmission mechanism, and a planetary reduction mechanism connected in sequence. The axes of all gears in the cutting transmission system extend horizontally front to back. In the front-back direction, the planetary reduction mechanism and the first-stage spur gear transmission mechanism are located at the foremost position, the second-stage spur gear transmission mechanism is located at the rearmost position, and the third-stage spur gear transmission mechanism is located between the first and second-stage spur gear transmission mechanisms. The cutting motor is arranged facing forward on the goaf side of the housing. The power output end of the cutting motor is coaxially connected to the input gear of the first-stage spur gear transmission mechanism, and the output gear of the third-stage spur gear transmission mechanism is coaxially connected to the sun gear of the planetary reduction mechanism. The rear part of the cutting motor and the motor cylinder in which it is located extend rearward and beyond the second-stage spur gear transmission mechanism.

[0007] The motor cylinder is provided with a wiring cavity for cutting the motor. The wiring cavity is preferably located at the rear end of the upper half of the motor cylinder and extends backward relative to the lower half of the motor cylinder.

[0008] The cutting motor is preferably a high power density motor.

[0009] The first-stage spur gear transmission mechanism includes a head gear, an idler gear, and a coal wall side gear that mesh externally in the transmission direction. The second-stage spur gear transmission mechanism includes a goaf side shaft gear and a goaf side gear that mesh externally in the transmission direction. The third-stage spur gear transmission mechanism includes a coal wall side shaft gear, an idler gear, and an end gear that mesh externally in the transmission direction. The idler gear in the first and third-stage spur gear transmission mechanisms can be a single idler gear or multiple idler gears that mesh externally in sequence. The coal wall side gear and the goaf side shaft gear are each rotatably supported in the housing by two sets of bearings. The coal wall side gear is coaxially splined with the goaf side shaft gear through a long splined shaft. The coal wall side shaft gear is rotatably supported in the housing by two sets of bearings located at its two ends. The goaf side gear is fitted onto the coal wall side shaft gear and splinedly connected to the coal wall side shaft gear. The head gear and the end gear respectively constitute the input gear of the first-stage spur gear transmission mechanism and the output gear of the third-stage spur gear transmission mechanism.

[0010] The coal face side shaft gear can be radially centered by engaging the cylindrical surfaces at both ends of its spline with the corresponding holes of the goaf side gear.

[0011] An oil storage chamber is provided between the large gear on the coal wall side and the shaft gear on the goaf side, and the long splined shaft connecting the large gear on the coal wall side and the shaft gear on the goaf side passes through the oil storage chamber.

[0012] The internal space of the housing is divided into multiple sealed chambers. The first-stage spur gear transmission mechanism, the second and third-stage spur gear transmission mechanism and the planetary reduction mechanism each occupy a sealed chamber, and a rotating frame seal is provided between two adjacent sealed chambers.

[0013] The shell wall structure contains non-communicating low-pressure water channels and high-pressure water channels. The outer shell is equipped with nozzles, the inlets of which are connected to the low-pressure water channels. The cooling water channels in the large end cover of the input gear of the first-stage spur gear transmission mechanism and the cooling water channels in the large end cover of the output gear of the third-stage spur gear transmission mechanism are both connected to the high-pressure water channels. The latter is connected to the end of the high-pressure water channels and is connected to the inlet of the internal spray water delivery mechanism.

[0014] A thin coal seam mining machine has a left and right cutting device, both of which are semi-suspended cutting devices. The left and right cutting devices are symmetrically arranged on the left and right sides of the machine body and are respectively hinged to the left and right traction walking parts. When the thin coal seam mining machine is installed in conjunction with a scraper conveyor, the cutting motor is located above and on both the inner and outer sides of the coal wall sidewall of the scraper conveyor, and the rear end of the cutting motor does not extend beyond the center of the middle trough of the scraper conveyor. The cutting transmission system is located on the outer side of the coal wall sidewall of the scraper conveyor.

[0015] The first-stage spur gear transmission mechanism is located in front of the scraper conveyor and maintains a certain distance from it. The second-stage and third-stage spur gear transmission mechanisms are located above the coal shovel plate on the outer side of the coal wall sidewall.

[0016] The left and right traction walking parts each have a traction motor and a traction transmission system inside their housings. The traction transmission system includes a first and second stage spur gear transmission system and a two-stage planetary reduction mechanism. Most of the traction motor and the traction transmission system are arranged above the coal wall side trough of the scraper conveyor.

[0017] The beneficial effects of this invention are:

[0018] In the semi-suspended cutting device of the present invention, the main body of the cutting device (referring to the cutting transmission system of the cutting device) is arranged on the outside of the coal wall sidewall of the scraper conveyor. The cutting motor is located above and on both the inner and outer sides of the coal wall sidewall of the scraper conveyor, and the rear end of the cutting motor does not extend beyond the center of the middle trough of the scraper conveyor. This releases the coal passage space above the middle trough of the scraper conveyor, increases the safety clearance with the hydraulic support, and relatively reduces the machine height. This avoids the influence of the cutting motor on the machine height and the coal passage space. Therefore, a larger power cutting motor can be configured to meet the high-efficiency mining requirements of thin coal seam working faces.

[0019] The cutting motor is arranged facing forward on the goaf side of the shell, which makes maintenance and replacement convenient in case of damage, saves costs, and reduces the labor intensity of workers.

[0020] The wiring cavity of the cutting motor is suspended in the upper half of the motor cylinder, which does not affect the coal passage space below the cutting motor.

[0021] The cutting motor is preferably a high-power-density motor, so the axial and radial dimensions of the cutting motor can be smaller, thus better meeting the requirements of the three-machine matching.

[0022] The cutting device employs a multi-section, segmented lubrication structure, which shortens the lubrication length of the oil and ensures that the oil can provide sufficient lubrication within its respective small, enclosed space when the cutting device is in different postures. This solves the problem of lubrication difficulties when the cutting device swings up and down.

[0023] The thin coal seam mining machine of this invention adopts a novel overall layout structure that combines a semi-suspended cutting device with a normal machine body, effectively resolving the contradiction between installed power, machine face height, and coal passage space. Because the center of gravity of this mining machine remains above the central trough of the scraper conveyor, it solves the instability and poor adaptability problems caused by the center of gravity being located on the coal face side in fully suspended mining machines, greatly improving the stability and adaptability of the thin coal seam mining machine. Attached Figure Description

[0024] Figure 1 This is a front view of an embodiment of the semi-suspended cutting device (left cutting device) of the present invention;

[0025] Figure 2 for Figure 1 A cross-sectional view of the embodiment shown;

[0026] Figure 3 This is a top view of one embodiment of the thin coal seam mining machine;

[0027] Figure 4 This is a front view of one embodiment of the thin coal seam mining machine;

[0028] Figure 5 This is a left view of one embodiment of the thin coal seam mining machine.

[0029] Figure label:

[0030] 1. Housing, 2. Cutting motor, 3. Clutch system, 4. Head gear, 5. Idler gear, 6. Coal wall side large gear, 7. Coal wall side shaft gear, 8. Idler gear, 9. Idler gear, 10. Planetary reduction mechanism, 11. Internal spray water delivery mechanism, 12. Drum, 13. Left cutting device, 14. Left traction and traveling unit, 15. Electrical control box, 16. Right traction and traveling unit, 17. Right cutting device, 18. Scraper conveyor, A. Water inlet, B. Water inlet, C. Traction transmission system, D. Traction motor, E. Oil storage chamber. Detailed Implementation

[0031] This invention discloses a semi-suspended cutting device (which may be simply referred to as a cutting device), such as... Figure 1 , 2 As shown in Figures 3, 4, and 5, the device includes a housing 1 and a cutting motor 2 and a cutting transmission system installed within the housing. The cutting transmission system comprises a first-stage spur gear transmission mechanism, a second-stage spur gear transmission mechanism, a third-stage spur gear transmission mechanism, and a planetary reduction mechanism 10, which are connected in sequence. The axes of all gears in the cutting transmission system extend horizontally forward and backward. In the forward and backward direction, the planetary reduction mechanism and the first-stage spur gear transmission mechanism are located at the foremost position, the second-stage spur gear transmission mechanism is located at the rearmost position, and the third-stage spur gear transmission mechanism is located between the first and second-stage spur gear transmission mechanisms. The planetary reduction mechanism and the first-stage spur gear transmission mechanism are arranged side-by-side with spacing. The cutting motor is positioned facing forward on the goaf side of the housing. The power output end of the cutting motor is coaxially connected to the input gear of the first-stage spur gear transmission mechanism, allowing for easy installation and removal from the goaf side of the housing. The output gear of the third-stage spur gear transmission mechanism is coaxially connected to the sun gear of the planetary reduction mechanism. The first-stage spur gear transmission mechanism is positioned close to the coal face and significantly beyond the second and third-stage spur gear transmission mechanisms. This allows for more installation space for the cutting motor, enabling it to be positioned more towards the coal face and greatly reducing its impact on the coal passage and machine height. The rear of the cutting motor and its associated motor housing (part of the casing) extend rearward beyond the second-stage spur gear transmission mechanism; that is, the rear of the cutting motor is located behind the cutting transmission system. The entire cutting device has an approximate H-shaped structure (see [link to relevant documentation]). Figure 2 The housing portion containing the first-stage spur gear transmission mechanism can act as a coal baffle, allowing the drum 12 to be repeatedly loaded with coal, thereby improving the coal loading efficiency of the drum.

[0032] The power output end of the cutting motor can be connected to the input gear of the first-stage spur gear transmission mechanism via a torque shaft. Preferably, the two ends of the torque shaft are connected to the power output end of the cutting motor and the input gear of the first-stage spur gear transmission mechanism using splines. Power is transmitted from the cutting motor to the first-stage spur gear transmission mechanism via the torque shaft.

[0033] The clutch system 3 is installed at the output end of the cutting motor. The clutch system cooperates with the input gear of the first-stage spur gear transmission mechanism to complete the clutch and engagement operations.

[0034] The motor housing may include a wiring cavity for cutting the motor. Preferably, the wiring cavity is located at the rear end of the upper half of the motor housing and extends rearward relative to the lower half of the motor housing. Figure 5 (As can be seen from the viewing angle), so the space below the wiring cavity can be used to pass through the coal flow, thereby increasing the coal passage space.

[0035] The cutting motor is preferably a high-power-density motor, so the axial and radial dimensions of the cutting motor can be smaller, thus better meeting the requirements of the three-machine matching.

[0036] The first-stage spur gear transmission mechanism may include a leading gear 4, an idler gear 5, and a coal wall side large gear 6 that mesh externally in the transmission direction. The second-stage spur gear transmission mechanism may include a goaf-side shaft gear and a goaf-side large gear that mesh externally in the transmission direction. The third-stage spur gear transmission mechanism may include a coal wall side shaft gear 7, idler gears 8 and 9, and a leading gear that mesh externally in the transmission direction. The idler gears in the first and third-stage spur gear transmission mechanisms can be a single idler gear or multiple idler gears meshing externally in sequence, and the number of idler gears in the first-stage and third-stage spur gear transmission mechanisms may be unequal. The coal wall side large gear and the goaf-side shaft gear are each rotatably supported within the housing by two sets of bearings, and the coal wall side large gear is coaxially splinedly connected to the goaf-side shaft gear via a long splined shaft. The first-stage spur gear transmission mechanism transmits power to the second-stage spur gear transmission mechanism through the long splined shaft. The coal wall side shaft gear is rotatably supported in the housing by two sets of bearings located at its two ends. The goaf side large gear is sleeved on the coal wall side shaft gear and splinedly connected to the coal wall side shaft gear. The first end gear and the last end gear respectively constitute the input end gear of the first stage spur gear transmission mechanism and the output end gear of the third stage spur gear transmission mechanism.

[0037] The coal face side shaft gear can be radially centered by engaging the cylindrical surfaces at both ends of its spline with the corresponding holes of the goaf side gear, thereby enhancing the stability of the spline connection.

[0038] The planetary reduction mechanism achieves lower output speed and higher output torque, increasing the cutting capacity of the drum. Employing a four-planet gear meshing transmission, the mechanism is compact, provides high transmission torque, and is reliable. The planetary reduction mechanism mainly comprises a sun gear, planet gears, an internal gear ring, a planet carrier, bearing housings, double-cone support bearings, a flat floating oil seal, and a square connecting sleeve. The splined end of the sun gear is connected to the internal spline of the output gear of the third-stage spur gear transmission mechanism, transmitting power from the third-stage spur gear transmission mechanism to the planetary reduction mechanism. When the sun gear rotates, it drives the planet gears to rotate around their own axes, simultaneously causing the planet carrier to rotate around the sun gear's axis. The internal gear ring remains stationary. The planet carrier of the planetary reduction mechanism is connected to the square connecting sleeve used to mount the drum via a spline, outputting torque to the drum. Because the planetary reduction mechanism uses a floating sun gear structure, the floating is sensitive, with low reaction torque. The amount of floating is controlled by the backlash of the external spline that meshes with the output gear of the third-stage spur gear transmission mechanism, ensuring even load distribution among the planet gears. The dynamic seal of the square connecting sleeve is achieved by a floating oil seal. This structure can adapt to the axial movement of the planetary reduction mechanism, so it can work for a long time in harsh working conditions with coal dust.

[0039] An oil storage chamber E is provided between the large gear on the coal face side and the shaft gear on the goaf side. A long splined shaft connecting the large gear on the coal face side and the shaft gear on the goaf side passes through the oil storage chamber. The oil storage chamber can ensure that the oil has a sufficiently large circulation space to carry out sufficient heat exchange, promote oil flow, improve heat dissipation performance, and enable the cutting device to quickly reach thermal equilibrium.

[0040] The internal space of the housing is preferably divided into multiple sealed chambers. The first-stage spur gear transmission mechanism, the second and third-stage spur gear transmission mechanisms, and the planetary reduction mechanism each occupy one sealed chamber. Two back-to-back rotating frame seals are installed between adjacent sealed chambers. The oil storage chamber is part of the sealed chamber occupied by the first-stage spur gear transmission mechanism. During the up-and-down swing of the rocker arm, the oil from the first-stage spur gear transmission mechanism will not flow into the second and third-stage spur gear transmission mechanisms, nor will the oil from the second and third-stage spur gear transmission mechanisms flow into the planetary reduction mechanism. This invention refers to this multi-sealed-chamber structure as a multi-segmented lubrication system. This multi-segmented lubrication system shortens the lubrication length of the oil, ensuring that the cutting device can achieve sufficient lubrication within its respective smaller sealed space when in different postures, thus solving the problem of difficult lubrication when the cutting device swings up and down.

[0041] The shell wall structure contains separate, non-communicating low-pressure water channels and high-pressure water channels, respectively corresponding to... Figure 2The system has inlet A and inlet B. Water from inlet A is reduced to 1.2 MPa by a pressure reducing valve and then enters the low-pressure water channel through inlet A. The outer shell of the housing is equipped with nozzles, the inlets of which are connected to the low-pressure water channel. Cooling water in the low-pressure water channel cools the housing and is then sprayed out from the nozzles for external spray cooling, thus achieving a cooling effect.

[0042] The cooling water channels in the large end cover of the input gear of the first-stage spur gear transmission mechanism and the cooling water channels in the large end cover of the output gear of the third-stage spur gear transmission mechanism are both connected to the high-pressure water channel. The latter is connected to the end of the high-pressure water channel and is connected to the inlet of the internal spray water delivery mechanism 11. The water from the B-path enters the high-pressure water channel of the shell directly from the B-inlet without passing through the pressure reducing valve. Then, it passes through the tubular cooler to cool the high-temperature oil near the input gear of the first-stage spur gear transmission mechanism. After entering the cooling water channel in the end cover of the input gear of the first-stage spur gear transmission mechanism and cooling the high-temperature oil near the end cover, it returns to the high-pressure water channel. Finally, it is connected to the internal spray water delivery mechanism through the cooling water channel in the large end cover of the output gear of the third-stage spur gear transmission mechanism and sprayed out from the nozzles on the drum 12 for internal spray dust suppression, thus playing a dust suppression role.

[0043] like Figure 3 , 4 As shown in Figure 5, this invention also discloses a thin coal seam mining machine, in which both the left cutting device 13 and the right cutting device 17 adopt the aforementioned semi-suspended cutting device. The mining machine body is a three-section body, including an electrical control box 15 and a left traction walking part 14 and a right traction walking part 16 arranged on both sides of the electrical control box. The left and right cutting devices are symmetrically arranged on the left and right sides of the machine body and are respectively hinged to the left traction walking part 14 and the right traction walking part 16. When the thin coal seam mining machine is installed in conjunction with the scraper conveyor 18, the cutting device is semi-suspended on the coal wall side of the mining machine body, that is, the cutting motor is laterally located above and on both the inner and outer sides of the coal wall side trough of the scraper conveyor, and the rear end of the cutting motor does not extend beyond the center of the middle trough of the scraper conveyor, and the cutting transmission system is located on the outer side of the coal wall side trough of the scraper conveyor.

[0044] Compared to the conventional arrangement of the cutting motor above the two sides of the scraper conveyor, the arrangement of the cutting motor in this invention is offset to the coal wall by more than half the length of the cutting motor, which significantly increases the coal passage height within the offset distance range, thus significantly increasing the coal passage space. At the same time, when the cutting device swings upward to adjust its height, it increases the safety clearance between itself and the hydraulic support, avoiding interference between itself and the top beam of the hydraulic support, and reducing the machine height compared to the conventional arrangement.

[0045] Since the first-stage spur gear transmission mechanism of the cutting device is located far beyond the second and third-stage spur gear transmission mechanisms and close to the coal wall side, it is beneficial to ensure that the rear of the cutting motor does not exceed the center of the scraper conveyor.

[0046] Furthermore, the first-stage spur gear transmission mechanism is located in front of the scraper conveyor and maintains a certain distance from it. The second-stage and third-stage spur gear transmission mechanisms are located above the coal shovel plate on the outer side of the coal wall sidewall. This avoids the cutting device's up-and-down swing affecting the coal passage space and machine face height of the mining machine. It is evident that neither the cutting motor nor the cutting transmission system affects the machine face height or coal passage space.

[0047] Each of the left and right traction and traveling sections houses a traction motor D and a traction transmission system C. The traction transmission system includes a first and second stage spur gear transmission system and a two-stage planetary reduction mechanism. Most of the traction motor and traction transmission system are located above and on both sides of the coal face side trough of the scraper conveyor, fully utilizing the space above the coal face side trough and the shovel plate. Traction power is output to the traveling wheels only through the long shaft, lowering the machine surface height above the two sides of the scraper conveyor, increasing the coal passage space, and reducing the machine surface height. Therefore, the traction motor D and traction transmission system C do not adversely affect the machine surface height or the coal passage space. This structural design effectively resolves the contradiction between installed power, machine surface height, and coal passage space. Moreover, the center of gravity of the entire coal mining machine remains above the middle trough of the scraper conveyor, solving the instability and poor adaptability problems caused by the center of gravity being located on the coal face side in fully suspended coal mining machines, greatly improving the stability and adaptability of thin coal seam mining machines.

[0048] Apart from the housing, all other internal components of the left and right cutting devices are interchangeable.

[0049] In this article, "front" and "back" refer to the direction closer to the coal face and the direction farther from the coal face, respectively.

Claims

1. A semi-suspended cutting device, characterized in that: The device includes a housing and a cutting motor and a cutting transmission system installed within the housing. The cutting transmission system comprises a first-stage spur gear transmission mechanism, a second-stage spur gear transmission mechanism, a third-stage spur gear transmission mechanism, and a planetary reduction mechanism, all sequentially connected. The axes of all gears in the cutting transmission system extend horizontally forward and backward. In the forward and backward direction, the planetary reduction mechanism and the first-stage spur gear transmission mechanism are located at the foremost position, the second-stage spur gear transmission mechanism is located at the rearmost position, and the third-stage spur gear transmission mechanism is located between the first and second-stage spur gear transmission mechanisms. The cutting motor is positioned facing forward on the goaf side of the housing, and the power output end of the cutting motor is forward-facing and connected to the first-stage spur gear transmission mechanism. The input gear is coaxially connected, and the output gear of the third-stage spur gear transmission mechanism is coaxially connected to the sun gear of the planetary reduction mechanism. The rear part of the cutting motor and the motor cylinder it is located in extend backward and beyond the second-stage spur gear transmission mechanism. The wiring cavity of the cutting motor is set in the motor cylinder. The wiring cavity is located at the rear end of the upper half of the motor cylinder and extends backward relative to the lower half of the motor cylinder. The internal space of the housing is divided into multiple sealed chambers. The first-stage spur gear transmission mechanism, the second and third-stage spur gear transmission mechanisms and the planetary reduction mechanism each occupy a sealed chamber. A rotating frame seal is set between two adjacent sealed chambers.

2. The semi-suspended cutting device according to claim 1, characterized in that: The cutting motor is a high power density motor.

3. The semi-suspended cutting device according to claim 1, characterized in that: The first-stage spur gear transmission mechanism includes a head gear, an idler gear, and a coal wall side gear that mesh externally in the transmission direction. The second-stage spur gear transmission mechanism includes a goaf side shaft gear and a goaf side gear that mesh externally in the transmission direction. The third-stage spur gear transmission mechanism includes a coal wall side shaft gear, an idler gear, and an end gear that mesh externally in the transmission direction. The idler gear in the first and third-stage spur gear transmission mechanisms can be a single idler gear or multiple idler gears that mesh externally in sequence. The coal wall side gear and the goaf side shaft gear are each rotatably supported in the housing by two sets of bearings. The coal wall side gear is coaxially splined with the goaf side shaft gear through a long splined shaft. The coal wall side shaft gear is rotatably supported in the housing by two sets of bearings located at its two ends. The goaf side gear is fitted onto the coal wall side shaft gear and splinedly connected to the coal wall side shaft gear. The head gear and the end gear respectively constitute the input gear of the first-stage spur gear transmission mechanism and the output gear of the third-stage spur gear transmission mechanism.

4. The semi-suspended cutting device according to claim 3, characterized in that: The coal wall side shaft gear uses the cylindrical surfaces located at both ends of its spline to engage with the corresponding holes of the goaf side gear to radially center the goaf side gear.

5. The semi-suspended cutting device according to claim 3, characterized in that: An oil storage chamber is provided between the large gear on the coal wall side and the shaft gear on the goaf side, and the long splined shaft connecting the large gear on the coal wall side and the shaft gear on the goaf side passes through the oil storage chamber.

6. The semi-suspended cutting device according to claim 1, 2, 3, 4 or 5, characterized in that: The shell wall structure contains non-communicating low-pressure water channels and high-pressure water channels. The outer shell is equipped with nozzles, the inlets of which are connected to the low-pressure water channels. The cooling water channels in the large end cover of the input gear of the first-stage spur gear transmission mechanism and the cooling water channels in the large end cover of the output gear of the third-stage spur gear transmission mechanism are both connected to the high-pressure water channels. The latter is connected to the end of the high-pressure water channels and is connected to the inlet of the internal spray water delivery mechanism.

7. A thin coal seam mining machine, characterized in that: Both the left and right cutting devices adopt the semi-suspended cutting device described in any one of claims 1-6. The left and right cutting devices are symmetrically arranged on the left and right sides of the machine body and are respectively hinged to the left traction walking part and the right traction walking part. When the thin coal seam mining machine is installed in conjunction with the scraper conveyor, the cutting motor is located above and on both the inner and outer sides of the coal wall side trough of the scraper conveyor, and the rear end of the cutting motor does not extend beyond the center of the middle trough of the scraper conveyor. The cutting transmission system is located on the outer side of the coal wall side trough of the scraper conveyor.

8. The thin coal seam mining machine as described in claim 7, characterized in that: The first-stage spur gear transmission mechanism is located in front of the scraper conveyor and maintains a certain distance from it. The second-stage and third-stage spur gear transmission mechanisms are located above the coal shovel plate on the outer side of the coal wall sidewall.

9. The thin coal seam mining machine as described in claim 8, characterized in that: The left and right traction walking parts each have a traction motor and a traction transmission system inside their housings. The traction transmission system includes a first and second stage spur gear transmission system and a two-stage planetary reduction mechanism. The entire traction motor and most of the traction transmission system are located above the coal wall side trough of the scraper conveyor.

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