Shearer rocker arm swing mechanism with a good working environment

Abstract

The present invention relates to a swing mechanism of a shearer arm with a good working environment, which includes an oil cylinder, an arm housing and a fixed reduction gearbox housing. The arm housing and the fixed reduction gearbox housing are respectively provided with first and second hinge seats. The first and second hinge seats are single-ear and double-ear seats respectively. The arm housing and the fixed reduction gearbox housing are paired and hinged through the first and second hinge seats. An independent oil cylinder installation cavity is provided in the fixed reduction gearbox housing. The oil cylinder installation cavity communicates with the outside through an opening between two connecting ears of the second hinge seat. An oil cylinder connecting ear is provided outside the connecting ear of the first hinge seat. The axis of the oil cylinder connecting ear is parallel to the axis of the ear hole of the first hinge seat. In the installed state, both the oil cylinder connecting ear and the oil cylinder are located in the oil cylinder installation cavity. One end of the oil cylinder is hinged to the oil cylinder connecting ear, and the other end is hinged to the fixed reduction gearbox housing. The present invention can solve the problem of coal and rock block accumulation at the oil cylinder connection, so the working reliability is high.

Description

Technical Field

[0001] The present invention relates to a swing mechanism of a shearer boom, which has a clean and safe working environment, so it has high working reliability. It can be used for shearers with low body height and can be used for mining thin coal seams and extremely thin coal seams in coal and rock working faces with more complex geological conditions. Background Art

[0002] The shearer boom is swing - connected relative to the shearer body or the fixed reduction gearbox part. One case of the power driving the boom swing comes from a rack mechanism driven by hydraulic pressure. The disadvantage of this mechanism is that it often requires a longer or wider space and is usually not applicable to shearers for thin coal seams. Another more common case is from an independent external cylinder. The cylinder is hinged to the boom, and the boom swings by the telescoping of the cylinder. It not only has a simple structure, but also is easy to realize hydraulic pressure drive. However, it also has disadvantages. For example, when encountering an inclined working face, whether the lower - placed cylinder is installed normally or reversely, the accumulated coal or rock blocks at the cylinder connection are likely to squeeze the cylinder, causing the cylinder to bear excessive radial force and fail. In response to this situation, currently, it mainly relies on maintenance methods such as regular inspection and cleaning of the accumulated coal to avoid or reduce the occurrence of failure, which is time - consuming and laborious. For high - cutting shearers, there is also a structure with the cylinder placed on the top of the body. Although the situation of accumulated coal and rock has improved, the cylinder is at risk of being damaged by large coal and rock blocks. Summary of the Invention

[0003] The present invention aims to provide a swing mechanism of a shearer boom with a good working environment, which can solve the problem of accumulated coal and rock blocks at the cylinder connection, so it has high working reliability.

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

[0005] A swing mechanism of a shearer boom with a good working environment, including an oil cylinder, a boom housing, and a fixed reduction gearbox housing. The boom housing and the fixed reduction gearbox housing are respectively provided with a first hinge seat and a second hinge seat. The first hinge seat and the second hinge seat are a single - ear ear seat and a double - ear ear seat respectively. The boom housing and the fixed reduction gearbox housing are hinged at the mating connection of the first hinge seat and the second hinge seat. An independent oil cylinder installation cavity is provided in the fixed reduction gearbox housing. The oil cylinder installation cavity communicates with the outside through an opening between two connecting ears of the second hinge seat. An oil cylinder connecting ear is provided outside the connecting ear of the first hinge seat. The axis of the oil cylinder connecting ear is parallel to the axis of the ear hole of the first hinge seat. In the installed state, the oil cylinder connecting ear and the oil cylinder are both located in the oil cylinder installation cavity. One end of the oil cylinder is hinged to the oil cylinder connecting ear, and the other end is hinged to the fixed reduction gearbox housing.

[0006] Preferably, an upper plate and a lower plate extending outward toward the outside of the boom housing are provided between the two connecting lugs of the second hinge seat. The upper plate and the lower plate are both part of the fixed reduction gear housing. The upper plate and the lower plate and the two connecting lugs of the second hinge seat enclose the open end from four directions of up, down, front and back. The outer ends of the upper plate and the lower plate are respectively arranged as an upper inner cylindrical surface and a lower inner cylindrical surface coaxial with the hinge axis of the second hinge seat. The outside of the connecting lug of the first hinge seat is provided with an upper outer cylindrical surface and a lower outer cylindrical surface coaxial with the hinge axis of the first hinge seat. The upper inner cylindrical surface and the upper outer cylindrical surface are in clearance fit, and the lower inner cylindrical surface and the lower outer cylindrical surface are in clearance fit. The circumferential angle formed by the upper inner cylindrical surface and the lower inner cylindrical surface on the side closer to the fixed reduction gear housing does not exceed 180 degrees.

[0007] The oil cylinder installation cavity is located on the coal wall side inside the fixed reduction gear housing. The coal wall side of the fixed reduction gear housing is an open structure. A side plate is installed on the coal wall side of the fixed reduction gear housing. The side plate, the fixed reduction gear housing and the first hinge seat enclose the closed oil cylinder installation cavity. A transmission mechanism installation cavity is also provided inside the fixed reduction gear housing. The transmission mechanism installation cavity is adjacent to the oil cylinder installation cavity and is located behind the oil cylinder installation cavity.

[0008] There is a mating clearance between the front and rear side surfaces of the first hinge seat and the opposite side surfaces on the front and rear two connecting lugs of the second hinge seat.

[0009] Furthermore, end face seals are also provided between the front and rear side surfaces of the first hinge seat and the opposite side surfaces on the front and rear two connecting lugs of the second hinge seat.

[0010] The boom housing may include a front support arm, a rear support arm and an L-shaped transmission box body. The transmission box body includes a left-right extension section and a front-rear extension section. The free end of the front-rear extension section is the front end. The front support arm and the rear support arm are respectively located in front of and behind the free ends of the left-right extension sections of the transmission box body. The front support arm and the rear support arm are both cantilever structures with one end connected to the transmission box body, and their main bodies both extend in the left-right direction. The first hinge seat is located on the front support arm and constitutes the free end of the front support arm. A third hinge seat is provided on the rear support arm and is paired with a fourth hinge seat on the fixed reduction gear housing to achieve hinged connection. The third hinge seat constitutes the free end of the rear support arm. The free ends of the left-right extension sections of the transmission box body are provided with a rear-stage transmission input interface structure, and a front-stage transmission output interface structure is correspondingly provided on the fixed reduction gear housing. In the installed state, the axes of the first hinge seat, the third hinge seat, the front-stage transmission output interface structure and the rear-stage transmission input interface structure coincide, and the front-stage transmission output interface structure and the rear-stage transmission input interface structure are coaxially connected.

[0011] The front support arm can be L-shaped. The free end of the left-right extension section of the front support arm is the free end of the front support arm. The rear end of the front-back extension section of the front support arm is connected to the transmission box body. The top surface of the front-back extension section of the front support arm is preferably an inclined surface, and the height is lower the farther away from the free end of the front support arm.

[0012] The beneficial effects of the present invention are as follows:

[0013] By arranging an independent oil cylinder installation cavity in the fixed reduction gearbox housing, placing the oil cylinder therein, and providing the only open port for the oil cylinder installation cavity to communicate with the outside at the connection between the fixed reduction gearbox housing and the boom housing, and setting the upper and lower edges of the open port to form upper and lower shaft hole clearance fit structures with the outer surfaces of the corresponding hinge seats on the boom housing, it not only does not affect the free swing of the boom housing, but also can effectively isolate impurities such as pulverized coal, always maintaining a clean working environment in the oil cylinder installation cavity and providing guarantee for the reliable operation of the oil cylinder.

[0014] Since the oil cylinder connecting ear is arranged outside the first hinge seat and the oil cylinder connecting ear is very close to the hinge axis between the boom housing and the fixed reduction gearbox housing, the force arm for driving the swing of the boom housing is short. Under the same oil cylinder stroke range, the swing angle range of the boom housing is larger, which is equivalent to a wider cutting height range that can be achieved.

[0015] Since the cutting transmission mechanism is arranged behind the oil cylinder, for a shearer with a suspended fuselage, the heavier components in the cutting transmission mechanism are closer to the gob side, which can shift the overall center of gravity of the shearer towards the gob side and closer to the position of the support leg (or scraper plate), improving the stability of the shearer in both the stationary state and the walking state.

[0016] A very small fitting clearance is maintained between the front and rear side surfaces of the connecting ear of the first hinge seat and the corresponding side surfaces of the front and rear two connecting ears of the second hinge seat, or an end face seal is also provided, which can further prevent a large amount of pulverized coal, etc. from entering the oil cylinder installation cavity and ensure the cleanliness of the oil cylinder installation cavity.

[0017] Since a plurality of support connection points are arranged between the boom housing and the housing of the fixed reduction gearbox, and these support connection points are respectively arranged in front of and behind the power transmission connection points of the cutting transmission mechanism, the radial displacement caused by wear at the front and rear support connection points has less influence on the power transmission connection point located between them. Therefore, this support connection structure can provide a more reliable guarantee for the transmission of cutting power.

[0018] By adding a front automatic lubrication device and a rear automatic lubrication device at the front and rear support connection points, automatic, effective, and long-term lubrication of the support stress surface can be ensured, wear can be reduced, and the service life of the support connection points can be extended.

[0019] The top surface of the front and rear extension sections of the front support arm is set as an inclined plane with a set angle and a specific highest point position, and the inclination direction of this inclined plane is that the height is lower as it is farther away from the free end of the front support arm. When the boom housing is in the upper cutting limit position, the entire front support arm is below the top surface of the housing of the fixed speed reducer, eliminating the interference between the front support arm and the coal platform. Brief Description of the Drawings

[0020] Figure 1 Structural schematic diagram of an embodiment of the present invention;

[0021] Figure 2 is Figure 1 A - A cross-sectional view of

[0022] Figure 3 Structural schematic diagram of the boom housing;

[0023] Figure 4 is Figure 3 B - B cross-sectional view of

[0024] Figure 5 Partial structural schematic diagram of the fixed speed reducer housing;

[0025] Figure 6 Schematic diagram of the state of a shearer using the swing arm swing mechanism of the present invention when the rear swing arm is in the upper cutting limit position.

[0026] Reference Numerals:

[0027] 1. Boom housing; 11. Transmission housing; 12. Front support arm; 121. First hinge seat; 1211. Oil cylinder connection ear; 1212. Upper outer cylindrical surface; 1213. Lower outer cylindrical surface; 1214. Front side; 1215. Rear side; 1216. Inclined plane; 13. Rear support arm; 131. Third hinge seat;

[0028] 2. Fixed speed reducer housing; 21. Oil cylinder installation cavity; 22. Transmission mechanism installation cavity; 23. Side plate; 24. Second hinge seat; 241. Side; 242. Side; 26. Side wall; 27. Upper plate; 271. Upper inner cylindrical surface; 28. Lower plate; 281. Lower inner cylindrical surface;

[0029] 3. Drum;

[0030] 4. Oil cylinder;

[0031] 5. Sealing ring;

[0032] 61. Front automatic lubrication device; 62. Rear automatic lubrication device. Detailed Description of the Invention

[0033] The present invention discloses a swing mechanism of a shearer arm (which can be simply referred to as the swing mechanism of the arm) with a good working environment, as Figures 1-6 shown, including an oil cylinder 4, an arm housing 1 and a fixed reduction gear housing 2. The arm housing and the fixed reduction gear housing are respectively provided with a first hinge seat 121 and a second hinge seat 24. The first hinge seat and the second hinge seat are a single-ear seat and a double-ear seat respectively. The arm housing and the fixed reduction gear housing are hinged at the mating connection of the first hinge seat and the second hinge seat, and the arm housing can swing relative to the fixed reduction gear housing around the hinge axis at this hinge point. An independent oil cylinder installation cavity 21 is provided in the fixed reduction gear housing, and the oil cylinder installation cavity communicates with the outside through an opening between two connecting ears of the second hinge seat. An oil cylinder connecting ear 1211 is provided outside the connecting ear of the first hinge seat, and the axis of the oil cylinder connecting ear is parallel to the axis of the ear hole of the first hinge seat. In the installed state, the oil cylinder connecting ear and the oil cylinder are both located in the oil cylinder installation cavity. One end of the oil cylinder is hinged to the oil cylinder connecting ear, and the other end is hinged to the fixed reduction gear housing. The telescoping of the oil cylinder will drive the arm housing to perform fixed-axis swinging. Since the oil cylinder and the connection between the oil cylinder and the arm housing are both located in the oil cylinder installation cavity, they can be isolated from the peripheral pulverized coal, so that the oil cylinder operates in a chamber with a relatively good working environment, with high working reliability and long service life.

[0034] Since the oil cylinder connecting ear is provided on the first hinge seat in this structure and is very close to the hinge axis between the arm housing and the fixed reduction gear housing, the force arm for driving the arm housing to swing is shorter. Under the same oil cylinder stroke range, the swing angle range of the arm housing is larger, which is equivalent to a wider cutting height range that can be achieved.

[0035] The oil cylinder connecting ear is preferably a double-ear seat.

[0036] The open end can be in various possible structural forms. For example, a relatively simple one is a flat opening directly formed on the side wall 26 of the fixed reduction gear housing where the second hinge seat is provided. In this embodiment, an upper plate 27 and a lower plate 28 extending outward toward the boom housing are provided between the two connecting lugs of the second hinge seat. Both the upper plate and the lower plate are part of the fixed reduction gear housing. For example, they can be continuous extensions of the top plate and the bottom plate of the fixed reduction gear housing locally. The upper plate, the lower plate, and the two connecting lugs of the second hinge seat enclose a space opening from four directions: up, down, front, and back. Compared with a simple flat opening, with the above-mentioned space opening and in cooperation with the first hinge seat, the channel from the oil cylinder installation cavity to the outside is narrower, which is more conducive to maintaining a good working environment in the oil cylinder installation cavity. The farthest extension of the upper plate and the lower plate in the left-right direction should preferably be controlled not to exceed the center of the second hinge seat. For the space opening, the upper plate and the lower plate can be further configured to have a tapered constriction structure at the outer ends of the extension to minimize the entry of pulverized coal and the like into the oil cylinder installation cavity. When there is a space opening, it is equivalent to a certain degree of outward expansion of the space range of the oil cylinder installation cavity. Therefore, a part of the outer end of the first hinge seat is usually also inside the oil cylinder installation cavity.

[0037] When the open end is a space opening, further, the upper edge and the lower edge of the open end (i.e., the outer ends of the upper plate and the lower plate) can be respectively configured as an upper inner cylindrical surface 271 and a lower inner cylindrical surface 281 coaxial with the hinge axis of the second hinge seat. An upper outer cylindrical surface 1212 and a lower outer cylindrical surface 1213 coaxial with the hinge axis of the first hinge seat are provided on the outside of the connecting lugs of the first hinge seat. The upper inner cylindrical surface and the upper outer cylindrical surface are in clearance fit, and the lower inner cylindrical surface and the lower outer cylindrical surface are in clearance fit. These two clearance fits not only do not affect the swing of the boom housing but also make the only open end of the oil cylinder installation cavity communicating with the outside relatively closed, which can better isolate foreign matters such as pulverized coal, thereby ensuring that a good working environment is always maintained in the oil cylinder installation cavity. The upper inner cylindrical surface, the lower inner cylindrical surface, the upper outer cylindrical surface, and the lower outer cylindrical surface are all non-circular cylindrical surfaces, but the central angles corresponding to the upper outer cylindrical surface and the lower outer cylindrical surface are much larger than the central angles corresponding to the upper inner cylindrical surface and the lower inner cylindrical surface to ensure that the above two clearance fits are always effective during the swing of the boom housing and keep the inside of the oil cylinder installation cavity always clean. The circumferential angle formed by the upper inner cylindrical surface and the lower inner cylindrical surface on the side closer to the fixed reduction gear housing should not exceed 180 degrees to ensure the smooth connection and installation between the first and second hinge seats. Inside the oil cylinder installation cavity, the upper outer cylindrical surface and the lower outer cylindrical surface are separated by the oil cylinder connecting lugs.

[0038] The upper plate and the lower plate can be connected to the two connecting lugs of the second hinge seat as a whole, or can be separated from the second hinge seat.

[0039] The cylinder installation cavity can be located on the coal wall side or the gob side within the fixed reduction gearbox housing. Usually, the coal wall side or the gob side of the fixed reduction gearbox housing is open. Side plates 23 are installed on the coal wall side or the gob side of the fixed reduction gearbox housing. The relatively enclosed cylinder installation cavity is formed by the side plates, the fixed reduction gearbox housing, and the first hinge seat. After removing the side plates, the cylinder can be disassembled and assembled.

[0040] Among them, setting the cylinder installation cavity on the coal wall side within the fixed reduction gearbox housing is a preferred solution, and this solution is adopted in this embodiment. A transmission mechanism installation cavity 22 is also provided within the fixed reduction gearbox housing. The transmission mechanism installation cavity is adjacent to the cylinder installation cavity and is located behind the cylinder installation cavity. For a shearer with a suspended fuselage structure, compared with the situation where the cutting transmission mechanism is located on the coal wall side, in the present invention, since the larger-weight components in the cutting transmission mechanism are closer to the gob side, the overall center of gravity of the shearer can be shifted towards the gob side, closer to the position of the support legs (or scraper plates), improving the stability of the shearer in both the stationary state and the walking state.

[0041] Preferably, a very small fitting clearance is maintained between the front and rear side surfaces 1214 and 1215 of the connecting ear of the first hinge seat and the opposite side surfaces 241 and 242 on the front and rear two connecting ears of the second hinge seat, further preventing a large amount of pulverized coal, etc. from entering the cavity and ensuring the cleanliness within the cylinder installation cavity.

[0042] Furthermore, annular sealing grooves can be respectively provided on the front and rear side surfaces 1214 and 1215 of the connecting ear of the first hinge seat, and sealing rings 5 are installed in the sealing grooves to achieve sealing between the adjacent end faces of the first hinge seat and the second hinge seat, further preventing pulverized coal from entering the cylinder installation cavity.

[0043] The boom housing can include a front support arm 12, a rear support arm 13, and an L-shaped transmission box body 11. The transmission box body includes a left-right extending section and a front-rear extending section. The free end of the front-rear extending section is the front end (i.e., the end closer to the coal wall side). The front support arm and the rear support arm are respectively located at the free ends of the left-right extending sections of the transmission box body (corresponding Figure 3The front support arm and the rear support arm are both cantilever structures with one end connected to the transmission box, and their main bodies extend in the left and right directions. The first articulated seat 121 is located on the front support arm and constitutes the free end of the front support arm. The rear support arm is provided with a third articulated seat 131, which is matched and connected with the fourth articulated seat on the fixed reduction box housing to achieve articulation, and the third articulated seat constitutes the free end of the rear support arm. The free ends of the left and right extension sections of the transmission box are provided with a rear-stage transmission input interface structure, and the fixed reduction box housing is correspondingly provided with a front-stage transmission output interface structure. In the installed state, the axes of the first articulated seat, the third articulated seat, the front-stage transmission output interface structure and the rear-stage transmission input interface structure coincide, and the front-stage transmission output interface structure and the rear-stage transmission input interface structure are coaxially connected. The arm housing is articulated with the fixed reduction box housing through the front and rear support arms, and swings around the fixed reduction box housing driven by the extension of the oil cylinder. The front-stage cutting transmission mechanism arranged in the fixed reduction box housing transmits power to the rear-stage cutting transmission mechanism located in the boom housing through the front-stage transmission output interface structure and the rear-stage transmission input interface structure, and finally drives the roller 3 installed on the front and rear extension sections of the boom housing to rotate on a fixed axis to cut coal. Since the support connection points formed between the boom housing and the fixed reduction box housing are respectively located in front of and behind the power transmission connection points of the front and rear cutting transmission mechanisms, the force state at the power transmission connection points is better, and the radial displacement caused by wear at the front and rear support connection points has less influence on the power transmission connection point located between the two, so the support connection structure can provide more reliable guarantee for the transmission of cutting power.

[0044] In this embodiment, the front support arm, the rear support arm and the transmission box are an integrated structure.

[0045] As a further preferred technical solution, the top surfaces of the front support arm and the rear support arm are not higher than the top surface of the transmission box, and the bottom surfaces of the front support arm and the rear support arm are not lower than the bottom surface of the transmission box, that is, the upper and lower thicknesses of the front support arm and the rear support arm are smaller than the transmission box, so as to avoid the interference between the front support arm and the rear support arm and the top coal platform when the arm frame housing is in the upper cutting limit position, so that the mining height can be higher. For the mining of extremely thin or thin coal seams, the rocker arm swing mechanism can achieve a lower mining lower limit and a higher mining upper limit, so that a wider mining range can be formed, which can be suitable for short-body coal mining machines.

[0046] The front support arm can be L-shaped. The free end of the left and right extension section of the front support arm is the free end of the front support arm. The rear end of the front and rear extension section of the front support arm is connected to the transmission box body. The top surface of the front and rear extension section of the front support arm is an inclined surface 1216, and the height is lower the farther away from the free end of the front support arm. The distance from the highest point of the inclined surface to the hinge axis of the first hinge seat is preferably not greater than the distance from the top surface of the housing of the fixed speed reducer to the hinge axis of the first hinge seat. The inclination angle of the inclined surface relative to the horizontal plane is preferably the included angle of the transmission box body relative to the horizontal plane when the boom housing is in the limit position of taking the upper knife, so that when the boom housing is in the limit position of taking the upper knife, the entire front support arm is below the top surface of the housing of the fixed speed reducer (see Figure 6 ).

[0047] The third hinge seat and the fourth hinge seat are a single-ear seat and a double-ear seat respectively. A front transition sleeve and a rear transition sleeve are coaxially and fixedly installed in the ear holes of the first hinge seat and the third hinge seat respectively. A pair of front wear-resistant sleeves and a pair of rear wear-resistant sleeves are fixedly installed in the ear holes of the second hinge seat and the fourth hinge seat respectively. The front pin shaft passes through the front transition sleeve and the front wear-resistant sleeve, and the rear pin shaft passes through the rear transition sleeve and the rear wear-resistant sleeve. The front pin shaft and the rear pin shaft are in clearance fit with the front transition sleeve and the rear transition sleeve respectively, and the front pin shaft and the rear pin shaft are in interference fit with the front wear-resistant sleeve and the rear wear-resistant sleeve respectively. Seals are provided between both ends of the front transition sleeve and the front support arm and the front pin shaft, and seals are provided between both ends of the rear transition sleeve and the rear support arm and the rear pin shaft. In this embodiment, annular seal grooves are provided at both axial ends of the outer cylindrical surface and the inner hole surface of the front transition sleeve, and annular seal grooves are provided at both axial ends of the outer cylindrical surface and the inner hole surface of the rear transition sleeve. Sealing rings are provided in the seal grooves to achieve the above sealing.

[0048] Front automatic lubrication devices 61 and rear automatic lubrication devices 62 are also provided on the front support arm and the rear support arm respectively. The lubrication points of the front automatic lubrication device and the rear automatic lubrication device are located on the inner hole surfaces of the front transition sleeve and the rear transition sleeve respectively. By adding the front automatic lubrication device and the rear automatic lubrication device at the front and rear support connection points, automatic, effective and long-term lubrication of the support stress surface can be ensured, wear can be reduced, and the service life of the support connection point can be extended.

Claims

1. A swing mechanism of a shearer arm with a good working environment, characterized in that: It includes an oil cylinder, a boom housing, and a fixed reduction gearbox housing. The boom housing and the fixed reduction gearbox housing are respectively provided with a first hinge seat and a second hinge seat. The first hinge seat and the second hinge seat are a single-ear seat and a double-ear seat respectively. The boom housing and the fixed reduction gearbox housing are hinged at the mating connection of the first hinge seat and the second hinge seat. An independent oil cylinder installation cavity is provided in the fixed reduction gearbox housing. The oil cylinder installation cavity communicates with the outside through an opening between two connecting ears of the second hinge seat. An oil cylinder connecting ear is provided outside the connecting ear of the first hinge seat. The axis of the oil cylinder connecting ear is parallel to the axis of the ear hole of the first hinge seat. In the installed state, both the oil cylinder connecting ear and the oil cylinder are located in the oil cylinder installation cavity. One end of the oil cylinder is hinged to the oil cylinder connecting ear, and the other end is hinged to the fixed reduction gearbox housing. An upper plate and a lower plate extending outward toward the boom housing are provided between the two connecting ears of the second hinge seat. The upper plate and the lower plate are both part of the fixed reduction gearbox housing. The upper plate, the lower plate, and the two connecting ears of the second hinge seat enclose the opening from four directions of up, down, front, and back. The outer ends of the upper plate and the lower plate are respectively set as an upper inner cylindrical surface and a lower inner cylindrical surface coaxial with the hinge axis of the second hinge seat. An upper outer cylindrical surface and a lower outer cylindrical surface coaxial with the hinge axis of the first hinge seat are provided outside the connecting ear of the first hinge seat. The upper inner cylindrical surface and the upper outer cylindrical surface are in clearance fit, and the lower inner cylindrical surface and the lower outer cylindrical surface are in clearance fit. The circumferential angle formed by the upper inner cylindrical surface and the lower inner cylindrical surface on the side closer to the fixed reduction gearbox housing does not exceed 180 degrees.

2. The swing mechanism of the shearer arm with a good working environment as described in claim 1, characterized in that: The oil cylinder installation cavity is located on the rib side or the gob side inside the fixed reduction gearbox housing. The rib side or the gob side of the fixed reduction gearbox housing is open. A side plate is installed on the rib side or the gob side of the fixed reduction gearbox housing. The side plate, the fixed reduction gearbox housing, and the first hinge seat enclose the closed oil cylinder installation cavity.

3. The swing mechanism of the shearer rocker arm with a good working environment according to claim 1, characterized in that: The oil cylinder installation cavity is located on the rib side inside the fixed reduction gearbox housing. The rib side of the fixed reduction gearbox housing is of an open structure. A side plate is installed on the rib side of the fixed reduction gearbox housing. The side plate, the fixed reduction gearbox housing, and the first hinge seat enclose the closed oil cylinder installation cavity. A transmission mechanism installation cavity is also provided in the fixed reduction gearbox housing. The transmission mechanism installation cavity is adjacent to the oil cylinder installation cavity and is located behind the oil cylinder installation cavity.

4. The swing mechanism of the shearer rocker arm with a good working environment as described in claim 1, characterized in that: There is a clearance between the front and rear side surfaces of the first hinge seat and the opposite side surfaces on the front and rear two connecting ears of the second hinge seat.

5. The swing mechanism of the shearer arm with a good working environment as described in claim 4, characterized in that: End face seals are provided between the front and rear side surfaces of the first hinge seat and the opposite side surfaces on the front and rear two connecting ears of the second hinge seat.

6. The swing mechanism of the shearer arm with a good working environment as described in claims 1, 2, 3, 4 or 5, characterized in that: The boom housing includes a front support arm, a rear support arm, and an L-shaped transmission housing. The transmission housing includes a left-right extending section and a front-rear extending section. The free end of the front-rear extending section is the front end. The front support arm and the rear support arm are respectively located in front of and behind the free ends of the left-right extending sections of the transmission housing. The front support arm and the rear support arm are both cantilever structures with one end connected to the transmission housing, and their main bodies extend in the left-right direction. The first hinge seat is located on the front support arm and constitutes the free end of the front support arm. A third hinge seat is provided on the rear support arm and is paired and connected with a fourth hinge seat on the fixed reduction gear housing to achieve hinging. The third hinge seat constitutes the free end of the rear support arm. A rear-stage transmission input interface structure is provided at the free end of the left-right extending section of the transmission housing, and a front-stage transmission output interface structure is correspondingly provided on the fixed reduction gear housing. In the installed state, the axes of the first hinge seat, the third hinge seat, the front-stage transmission output interface structure, and the rear-stage transmission input interface structure coincide, and the front-stage transmission output interface structure and the rear-stage transmission input interface structure are coaxially connected.

7. The swing mechanism of the shearer arm with a good working environment as described in claim 6, characterized in that: The front support arm is L-shaped. The free end of the left-right extending section of the front support arm is the free end of the front support arm. The rear end of the front-rear extending section of the front support arm is connected to the transmission housing. The top surface of the front-rear extending section of the front support arm is an inclined surface, and the height is lower the farther away from the free end of the front support arm.

8. The swing mechanism of the shearer rocker arm with a good working environment according to claim 6, characterized in that: The third hinge seat and the fourth hinge seat are respectively a single-ear ear seat and a double-ear ear seat. A front transition sleeve and a rear transition sleeve are coaxially and fixedly installed in the ear holes of the first hinge seat and the third hinge seat respectively. A pair of front wear-resistant sleeves and a pair of rear wear-resistant sleeves are fixedly installed in the ear holes of the second hinge seat and the fourth hinge seat respectively. The front pin shaft passes through the front transition sleeve and the front wear-resistant sleeve, and the rear pin shaft passes through the rear transition sleeve and the rear wear-resistant sleeve. The front pin shaft and the rear pin shaft are respectively in clearance fit with the front transition sleeve and the rear transition sleeve, and the front pin shaft and the rear pin shaft are respectively in interference fit with the front wear-resistant sleeve and the rear wear-resistant sleeve.

9. The swing mechanism of the shearer rocker arm with a good working environment according to claim 7, characterized in that: The third hinge seat and the fourth hinge seat are respectively a single-ear ear seat and a double-ear ear seat. A front transition sleeve and a rear transition sleeve are coaxially and fixedly installed in the ear holes of the first hinge seat and the third hinge seat respectively. A pair of front wear-resistant sleeves and a pair of rear wear-resistant sleeves are fixedly installed in the ear holes of the second hinge seat and the fourth hinge seat respectively. The front pin shaft passes through the front transition sleeve and the front wear-resistant sleeve, and the rear pin shaft passes through the rear transition sleeve and the rear wear-resistant sleeve. The front pin shaft and the rear pin shaft are respectively in clearance fit with the front transition sleeve and the rear transition sleeve, and the front pin shaft and the rear pin shaft are respectively in interference fit with the front wear-resistant sleeve and the rear wear-resistant sleeve.

10. The swing mechanism of the shearer boom with a good working environment as described in claim 8, characterized in that: The front support arm and the rear support arm are also respectively provided with a front automatic lubrication device and a rear automatic lubrication device. The lubrication points of the front automatic lubrication device and the rear automatic lubrication device are respectively located on the inner hole surfaces of the front transition sleeve and the rear transition sleeve.

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