Thin coal seam pre-slotting mining method suitable for wide mining range

Abstract

The invention relates to a thin coal seam pre-slotting mining method suitable for a wide mining range, a drum-type coal mining machine comprising a left cutting part and a right cutting part is adopted for mining, each cutting part comprises a main rocker arm and an auxiliary arm, and the auxiliary arm can slide back and forth relative to the main rocker arm; in the mining process, the main cutting depth that the front end section line of the auxiliary arm roller is larger than the front end section line of the main rocker arm roller by (0, 1) times is set, the coal mining machine walks back and forth left and right along the working face to mine once, the corresponding strokes sequentially comprise the forward stroke and the reverse stroke, and the front auxiliary arm roller and the rear auxiliary arm roller in the forward stroke and the reverse stroke cut forward and reverse grooves of the cutter respectively. And the main rocker arm does not participate in mining in the first forward stroke, and the main rocker arm rollers are used for mining coal at the top and the bottom of the groove formed in the forward direction or the reverse direction of the previous stroke from the beginning of the first reverse stroke. The adaptability of the suspension motor high-power thin seam mining machine to the wide mining height change range can be improved.

Description

Technical Field

[0001] The invention relates to a thin coal seam mining process, in particular to a thin coal seam mining process using a drum coal mining machine with a suspended motor rocker arm to mine locally thicker coal seams, the process adapts to a locally wider mining height range by pre-grooving the coal seam. Background Art

[0002] As the conditions of thin or relatively thin coal seams become more complicated, such as interlayers, faults, and partial crushing of the roof and floor, the power of coal mining machines is getting higher and higher to improve the reliability of the equipment. However, the increase in the volume of the cutting motor has led to a significant compression of the coal passing space between the cutting motor and the conveyor, and large pieces of coal rock cannot pass through, affecting the mining efficiency. In order to alleviate this problem, the cutting motor of the current mainstream high-power thin coal seam coal mining machine adopts a layout type suspended to the coal wall side (for the convenience of quoting later, this layout type is referred to as a suspended motor structure, the cutting motor of this layout type is referred to as a suspended motor, the corresponding rocker arm is referred to as a suspended motor rocker arm, and the corresponding coal mining machine is referred to as a suspended motor coal mining machine). However, this suspended motor structure has a great influence on the mining process.

[0003] When a high-power thin coal seam shearer with a suspended motor structure is used for mining, the front drum is generally used to cut the bottom knife and the rear drum is used to cut the top knife. The front drum cuts out the passage space for the front rocker arm suspended motor and the rear rocker arm suspended motor. Since the gap between the lifted suspended motor and the upper coal platform is small, or when the mining height of the rear drum is too high, the cutting motor will interfere with the upper coal platform, so the maximum mining height of the rear drum is generally small, making the total mining range very narrow, which leads to the poor adaptability of the suspended motor structure to the mining height. The rear drum is located at the top and is basically not loaded. The loading effect of the front drum is general when the drum diameter is small, so the total loading effect of the suspended motor shearer is also poor. Based on the above-mentioned major influences, for working faces with large changes in mining height, it is necessary to return to secondary mining and loading operations, which seriously affects the mining efficiency, or for locally thickened coal seams, some coal is discarded, resulting in a large waste of resources, and if the top coal is discarded, this part of the coal may collapse locally and cause roof management problems. Summary of the invention

[0004] The present invention provides a thin coal seam pre-grooving mining method that is adaptable to a wide mining range. Pre-grooving provides passage space for a suspended motor and operating space for a rocker arm equipped with a suspended motor, thereby removing the limitation of the suspended motor structure on the mining height and improving the adaptability of a high-power thin coal seam coal mining machine with a suspended motor to a wide range of mining height changes.

[0005] The main technical solutions of the present invention are:

[0006] A method for pre-slotting and mining thin coal seams suitable for a wide mining range, using a drum-type coal mining machine including two sets of left and right cutting parts for mining, each set of cutting parts including a main rocker arm, an auxiliary arm and a telescopic drive device, the main rocker arm and the auxiliary arm have their own independent power systems, one end of the main rocker arm is hinged on the body of the coal mining machine, and the other end is equipped with a main rocker arm drum, the main rocker arm changes its swing angle by telescoping a height adjustment cylinder connected between the main rocker arm and the body, the main rocker arm adopts a suspended motor rocker arm, an auxiliary arm drum is installed at the front end of the auxiliary arm, the rear part of the auxiliary arm is installed on the main rocker arm housing of the main rocker arm and cooperates with the main rocker arm housing to slide forward and backward, the auxiliary arm can slide forward and backward relative to the main rocker arm under the drive of the telescopic drive device, the cutting width of the auxiliary arm drum is not less than the cutting width of the main rocker arm drum, and the auxiliary arm When it is at the rear end of the forward and backward sliding stroke, the front end section of the auxiliary arm drum is flush with the front end section of the main rocker arm drum. When the auxiliary arm is at the front end of the forward and backward sliding stroke, the front end section of the auxiliary arm drum is ahead of the front end section of the main rocker arm drum by a distance not less than the cutting width of the main rocker arm drum. The coal mining machine moves back and forth along the working face left and right, and mining is one cut. The corresponding stroke includes forward stroke and reverse stroke in sequence. The main rocker arms in front and rear of the walking direction are respectively called the front main rocker arm and the rear main rocker arm, and the auxiliary arms in front and rear of the walking direction are respectively called the front auxiliary arm and the rear auxiliary arm. Before mining, the front end section of the auxiliary arm drum is set to be ahead of the front end section of the main rocker arm drum by a distance and maintained during the mining process. The distance is taken between (0,1] times the main cutting depth. The mining process is:

[0007] The first cutter forward stroke mining: the two main rocker arms do not participate in mining, the front and rear auxiliary arm rollers respectively groove upward and groove downward and form upper grooves and lower grooves respectively, and the upper grooves and lower grooves are superimposed to form the first cutter forward groove;

[0008] The first knife reverse stroke mining: the coal mining machine moves one step distance along with the conveyor and the support toward the direction close to the coal wall, and the front and rear main rocker arm rollers respectively mine the coal at the top and bottom of the slot opened by the first knife forward, while the front and rear auxiliary arm rollers respectively open slots upward and downward to form upper and lower slots respectively, and the upper and lower slots are superimposed to form the first knife reverse slot;

[0009] The second knife forward stroke mining: the coal mining machine moves one step distance in the direction close to the coal wall along with the conveyor and the support, and the front and rear main rocker arm rollers respectively mine the coal at the top and bottom of the slot opened by the first knife in reverse, while the front and rear auxiliary arm rollers respectively open the slot upward and downward to form the upper slot and the lower slot respectively, and the upper slot and the lower slot are superimposed to form the second knife forward slot;

[0010] The second knife reverse stroke mining: the coal mining machine moves one step distance along with the conveyor and the support toward the direction close to the coal wall, and the front and rear main rocker arm rollers respectively mine the coal at the top and bottom of the slot opened by the second knife in the forward direction, while the front and rear auxiliary arm rollers respectively open slots upward and downward to form the upper slot and the lower slot respectively, and the upper slot and the lower slot are superimposed to form the reverse slot opened by the second knife;

[0011] Continue the subsequent mining in a reciprocating manner according to the second mining method;

[0012] The lower slot mined in the current stroke should include the passage space of the suspension motor of the rear main rocker arm and the passage space of the rear auxiliary arm and its telescopic drive device when the rear main rocker arm roller mines the coal at the bottom of the slot in the next stroke; the upper slot mined in the current stroke should include the passage space of the suspension motor of the front main rocker arm and the passage space of the front auxiliary arm and its telescopic drive device when the front main rocker arm roller mines the coal at the top of the slot in the next stroke, or the superposition of the upper slot mined in the current stroke and the space cut out when the front main rocker arm roller mines the coal at the top of the slot in the next stroke should include the passage space of the suspension motor of the front main rocker arm and the passage space of the front auxiliary arm and its telescopic drive device when the front main rocker arm roller mines the coal at the top of the slot in the next stroke;

[0013] The lowest point of the main rocker arm roller before the current stroke is not higher than the upper section of the upper groove mined in the previous stroke, and the lowest point of the front auxiliary arm roller in the same stroke is not higher than the highest point of the rear auxiliary arm roller.

[0014] The diameter of the auxiliary arm roller is smaller than the diameter of the main rocker arm roller.

[0015] When the front and rear main rocker arm rollers mine the coal at the top and bottom of the trough respectively, the front main rocker arm roller loads a small amount of coal, and the rear main rocker arm roller loads most of the coal.

[0016] Before mining, the front end section line of the auxiliary arm drum is set to be ahead of the front end section line of the main rocker arm drum by half the main cutting depth or one main cutting depth and this distance is maintained during the mining process.

[0017] The step length is equal to the distance of a main cutting depth.

[0018] The lower groove mined in the current stroke should include the passage space for the suspension motor of the rear main rocker arm and the passage space for the rear auxiliary arm and its telescopic drive device when the rear main rocker arm roller mines the coal at the bottom of the groove in the next stroke, and leave a certain margin; the upper groove mined in the current stroke should include the passage space for the suspension motor of the front main rocker arm and the passage space for the front auxiliary arm and its telescopic drive device when the front main rocker arm roller mines the coal at the top of the groove in the next stroke, and leave a certain margin, or the superposition of the upper groove mined in the current stroke and the space cut out when the front main rocker arm roller mines the coal at the top of the groove in the next stroke should include the passage space for the suspension motor of the front main rocker arm and the passage space for the front auxiliary arm and its telescopic drive device when the front main rocker arm roller mines the coal at the top of the groove in the next stroke, and leave a certain margin.

[0019] The main rocker arm housing of the main rocker arm is provided with an auxiliary arm mounting hole extending forward and backward. The auxiliary arm is mounted on the main rocker arm housing with the help of a telescopic cylinder. The telescopic cylinder includes a cylinder body with two ends penetrating therethrough and a swing drive device mounting frame cantilevered in front of the cylinder body. The cylinder body is inserted into the auxiliary arm mounting hole and forms a front and rear sliding fit with the main rocker arm housing. The swing drive device mounting frame is close to the main rocker arm drum in the left and right directions. The auxiliary arm housing of the auxiliary arm includes an auxiliary arm frame and a cylindrical front overhanging portion and a cylindrical rear overhanging portion extending forward and backward respectively from the auxiliary arm frame. The auxiliary arm frame is in the shape of a strip box that is flat and thin front and back and extends left and right. The front overhanging portion and the rear overhanging portion are respectively close to the main rocker arm drum. At the left and right ends of the auxiliary arm frame, the auxiliary arm rollers are covered on the radial outer side of the front overhang, and the rear overhang is inserted into the cylinder from front to rear and forms a rotational connection with the cylinder. In the left and right directions, the front overhang is farther away from the main rocker arm roller than the rear overhang; the two ends of a swing drive cylinder are respectively hinged on the swing drive device mounting frame and the auxiliary arm frame, and the hinge axes of the two hinges extend horizontally front and back. Driven by the extension and contraction of the swing drive cylinder, the auxiliary arm can swing around the axis of the cylinder; on the basis of adjusting the swing angle of the main rocker arm, the swing angle of the auxiliary arm around the axis of the cylinder is changed by controlling the extension and contraction of the swing drive cylinder, and the height of the corresponding auxiliary arm roller is fine-tuned.

[0020] The beneficial effects of the present invention are:

[0021] The pre-grooving of the main cutter implemented by the auxiliary arm cuts out the passage space for the suspension motor of the main rocker arm of the subsequent cutter and the telescopic tube of the auxiliary arm, as well as the working space of the main rocker arm and the auxiliary arm, thus removing the restriction of the suspension motor structure on the upward swing angle of the main rocker arm and widening the mining height variation range of the coal mining machine.

[0022] By controlling the lowest point of the main rocker arm roller before the current stroke to be no higher than the upper cutting surface of the upper groove mined in the previous stroke, the top coal mining of the current knife and the pre-grooving of the front knife are superimposed to ensure the normal passage of the suspension motor of the front main rocker arm.

[0023] By having both the left and right auxiliary arm rollers participate in pre-grooving, wider pre-grooves can be formed above and below, greatly improving the mining adaptability of the suspended motor coal mining machine and basically meeting full coverage of thin coal seams with a wide mining height range.

[0024] Furthermore, when the cutting section includes a swing drive cylinder, the height of the front and rear auxiliary arm rollers can be adjusted independently, so that the slotting position is more flexible and can accommodate a wider range of total cutting heights.

[0025] The suspended motor of the front main rocker arm and the extended front auxiliary arm are located behind the forward direction of the front main rocker arm drum, which plays a role in blocking coal, thereby improving the loading effect of the front main rocker arm drum and enabling it to load the upper part of the coal, thereby reducing the loading requirements for the rear main rocker arm drum.

[0026] The pre-grooving operation reduces the hardness of the coal wall and reduces the amount of coal that needs to be mined in the next pass, thereby reducing the energy consumption of mining in the next pass.

[0027] The single-sided cutting part of the coal mining machine used in the present invention has two independent power systems, which is equivalent to splitting the original single cutting system into a main and auxiliary system. More space can be fully utilized to set the main rocker arm and the auxiliary arm, so that the total cutting power of the single-sided cutting part can be increased, and the cutting capacity is improved, and the cutting system power of the original rocker arm (corresponding to the main rocker arm in the present invention) can even be appropriately reduced, so that the increase in the volume of key components of the coal mining machine and the resulting insufficient equipment adaptability, large loss of effective cutting power and other problems can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a schematic diagram of the first knife forward stroke mining state (main viewing direction) of Example 1;

[0029] Figure 2 This is a schematic diagram of the first knife forward stroke mining state (top view) of Example 1;

[0030] Figure 3 This is a diagram of the coal wall state after the first knife forward stroke mining in Example 1;

[0031] Figure 4 This is a schematic diagram of the reverse stroke mining state (main viewing direction) of the first cutter of Example 1;

[0032] Figure 5 This is a schematic diagram of the reverse stroke mining state (viewed from top) of the first cutter of Example 1;

[0033] Figure 6 This is a schematic diagram of the mining state (viewed from top) of the second cutter in the forward stroke of the first embodiment;

[0034] Figure 7This is a diagram of the coal mining machine in the mining state of Example 1 from the left;

[0035] Figure 8 It is a schematic diagram of the mining height adjustment of the coal mining machine when the coal seam becomes thicker locally during the thin coal seam mining;

[0036] Fig. 9 This is a schematic diagram of the first cutter forward stroke mining state (top view) of Example 2;

[0037] Fig.10 This is a schematic diagram of the reverse stroke mining state (viewed from top) of the first cutter of Example 2;

[0038] Fig.11 This is a schematic diagram of the mining state (viewed from top) of the second cutter in the forward stroke of the second embodiment;

[0039] Fig.12 A schematic structural diagram of an embodiment of the right cutting portion of a coal mining machine used in the method of the present invention;

[0040] Fig.13 for Fig.12 A cross-sectional view of the cutting portion shown (the telescopic cylinder is in a retracted state);

[0041] Fig.14 for Fig.13 AA section view;

[0042] Fig.15 for Fig.13 BB cross-sectional view;

[0043] Fig.16 is a structural schematic diagram of an embodiment of the auxiliary arm;

[0044] Fig.17 for Fig.16 CC section view;

[0045] Fig.18 for Fig.16 A schematic diagram of the structure of the auxiliary arm housing in a top view;

[0046] Fig.19 for Fig.13 A schematic structural diagram of the main rocker arm housing;

[0047] Fig. 20 for Fig.12 A schematic structural diagram of the main rocker arm described in;

[0048] Fig.21 for Fig. 20 A cross-sectional view of the main rocker arm shown;

[0049] Fig. 22 is a structural schematic diagram of an embodiment of the telescopic cylinder;

[0050] Fig.23 for Fig. 22 FF cross-sectional view;

[0051] Fig.24 It is a schematic diagram of the auxiliary arm roller swinging upward when the swing drive cylinder is in the retracted state;

[0052] Fig.25 It is a schematic diagram of the auxiliary arm roller swinging down when the swing drive cylinder is in the extended state;

[0053] Fig.26 for Fig.12 A cross-sectional view of the cutting portion shown (the telescopic cylinder is in the extended state).

[0054] Reference numerals:

[0055] 01. Machine body; 02. Conveyor; 03. Support; 04. Coal at the top of the slot with the first knife in the forward groove; 05. Coal at the bottom of the slot with the first knife in the forward groove; 06. Coal at the top of the slot with the first knife in the reverse groove; 07. Coal at the bottom of the slot with the first knife in the reverse groove; 08. Forward groove with the first knife; 08'. Reverse groove with the first knife; 08". Forward groove with the second knife;

[0056] 1. (right side) main rocker arm; 11. main rocker arm housing; 101. auxiliary arm mounting hole; 102. upper guide surface and lower guide surface; 103. telescopic drive device mounting hole; 105. protective edge; 111. fuselage articulated seat; 112. height adjustment cylinder articulated seat; 113. main rocker arm motor mounting hole; 114. main rocker arm transmission mechanism mounting cavity; 12. main rocker arm motor; 13. main rocker arm transmission mechanism; 132. main rocker arm planetary reduction mechanism; 14. (right side) main rocker arm roller; 14'. left main rocker arm roller; 17. main rocker arm clutch;

[0057] 2. Auxiliary arm; 21. Auxiliary arm housing; 211. Rear overhang; 212. Auxiliary arm arm frame; 213. Front overhang; 22. Auxiliary arm motor; 23. Auxiliary arm transmission system; 232. Auxiliary arm planetary reduction mechanism; 233. Input end gear; 234. Output end gear; 24. (right side) auxiliary arm roller; 24'. Left side auxiliary arm roller; 25. Auxiliary arm clutch;

[0058] 3. Telescopic drive device; 31. Mounting seat of main rocker arm end of telescopic drive device; 32. Telescopic oil cylinder; 33. Mounting seat of auxiliary arm end of telescopic drive device; 331. Upper and lower sides;

[0059] 4. Telescopic cylinder; 41. Cylinder body; 42. Swing drive device mounting frame;

[0060] 5. Swing drive device; 51. Mounting seat for telescopic cylinder end of swing drive device; 52. Swing drive oil cylinder; 53. Mounting seat for auxiliary arm end of swing drive device;

[0061] 61. Limit block. DETAILED DESCRIPTION

[0062] like Figure 1-26 As shown, the present invention discloses a pre-grooving mining method for thin coal seams suitable for a wide mining range, and adopts a drum-type coal mining machine including two sets of left and right cutting parts for mining, each set of cutting parts includes a main rocker arm 1, an auxiliary arm 2 and a telescopic drive device 3, and the main rocker arm and the auxiliary arm have their own independent power systems. One end of the main rocker arm is hinged on the body 01 of the coal mining machine, and the other end is installed with a main rocker arm drum 14. The main rocker arm changes the swing angle by telescoping the height adjustment cylinder connected between the main rocker arm and the body. The main rocker arm adopts a suspended motor rocker arm. An auxiliary arm drum 24 is installed at the front end of the auxiliary arm, and the rear part of the auxiliary arm is installed on the main rocker arm housing of the main rocker arm and cooperates with the main rocker arm housing to slide forward and backward. The auxiliary arm can slide forward and backward relative to the main rocker arm under the drive of the telescopic drive device. The cutting width of the auxiliary arm drum is not less than the cutting width of the main rocker arm drum. When the auxiliary arm is at the rear end of the front-to-back sliding stroke, the front end section line of the auxiliary arm drum is flush with the front end section line of the main rocker arm drum. When the auxiliary arm is at the front end of the front-to-back sliding stroke, the front end section line of the auxiliary arm drum is ahead of the front end section line of the main rocker arm drum by a distance not less than the cutting width of the main rocker arm drum. The cutting widths of the auxiliary arm drum and the main rocker arm drum are usually equal.

[0063] In the attached drawings, 14 and 24 respectively represent the right main rocker arm drum and the right auxiliary arm drum of the coal mining machine, and 14' and 24' respectively represent the left main rocker arm drum and the left auxiliary arm drum of the coal mining machine.

[0064] The coal mining machine moves back and forth along the working face left and right, and one mining is called one cut. The corresponding stroke includes forward stroke and reverse stroke in sequence. For the convenience of description, the main rocker arms in front and rear of the walking direction are called front main rocker arms and rear main rocker arms, respectively, and the auxiliary arms in front and rear of the walking direction are called front auxiliary arms and rear auxiliary arms, respectively. For example, if mining to the right is a forward stroke, mining to the left is a reverse stroke. When mining to the right, the front and rear of the walking direction are right and left respectively, and the corresponding front and rear main rocker arms are the right main rocker arms and the left main rocker arms, respectively, and the front and rear auxiliary arms are the right auxiliary arms and the left auxiliary arms, respectively.

[0065] Before mining, the front end section of the auxiliary arm drum is set to be ahead of the front end section of the main rocker arm drum by a distance B and this distance is maintained during mining. The distance B is between (0,1] times the main cutting depth H (referring to the width of the coal cut by the main rocker arm drum in the direction of the coal mining machine advancing along the working face, usually equal to the cutting width of the main rocker arm drum), that is, 0<B≤H. The worse the roof conditions, the smaller the value of B.

[0066] like Figure 1-11 As shown, the mining process is:

[0067] The first cutter forward stroke mining: the two main rocker arms do not participate in mining, the front and rear auxiliary arm rollers respectively groove upward and groove downward and form the upper groove and the lower groove respectively, the upper groove and the lower groove are superimposed to form the first cutter forward groove 08;

[0068] The first knife reverse stroke mining: the coal mining machine moves one step distance in the direction close to the coal wall along with the conveyor 02 and the support 03, and the front and rear main rocker arm rollers respectively mine the top coal 04 and the bottom coal 05 of the first knife forward slot (i.e., they cut the top and cut the bottom respectively, the same below), and at the same time, the front and rear auxiliary arm rollers respectively slot upward and downward to form the upper slot and the lower slot respectively, and the upper slot and the lower slot are superimposed to form the first knife reverse slot 08';

[0069] The second knife forward stroke mining: the coal mining machine moves one step distance with the conveyor and the support towards the direction close to the coal wall, and the front and rear main rocker arm rollers respectively mine the top coal 06 and the bottom coal 07 of the first knife reverse slotting, while the front and rear auxiliary arm rollers respectively slot upward and downward to form the upper slot and the lower slot respectively, and the upper slot and the lower slot are superimposed to form the second knife forward slot 08";

[0070] The second knife reverse stroke mining: the coal mining machine moves one step distance along with the conveyor and the support toward the direction close to the coal wall, and the front and rear main rocker arm rollers respectively mine the coal at the top and bottom of the slot opened by the second knife in the forward direction, while the front and rear auxiliary arm rollers respectively open slots upward and downward to form the upper slot and the lower slot respectively, and the upper slot and the lower slot are superimposed to form the reverse slot opened by the second knife;

[0071] The subsequent mining is continued in a repetitive cycle according to the second mining method.

[0072] The lower groove mined in the current stroke should include the passage space for the suspension motor of the rear main rocker arm and the passage space for the rear auxiliary arm and its telescopic drive device when the rear main rocker arm roller mines the coal at the bottom of the groove in the next stroke; the upper groove mined in the current stroke should include the passage space for the suspension motor of the front main rocker arm and the passage space for the front auxiliary arm and its telescopic drive device when the front main rocker arm roller mines the coal at the top of the groove in the next stroke, or the superposition of the upper groove mined in the current stroke and the space cut out when the front main rocker arm roller mines the coal at the top of the groove in the next stroke should include the passage space for the suspension motor of the front main rocker arm and the passage space for the front auxiliary arm and its telescopic drive device when the front main rocker arm roller mines the coal at the top of the groove in the next stroke.

[0073] The lowest point of the main rocker arm roller before the current stroke is not higher than the upper section of the upper slot mined in the previous stroke, that is, there is no coal platform in the middle after the main rocker arm roller before the current stroke and the auxiliary arm roller before the previous stroke are superimposed and mined. The lowest point of the front auxiliary arm roller of the same stroke is not higher than the highest point of the rear auxiliary arm roller, that is, there is no coal platform in the middle of the superposition of the upper and lower slots of the same stroke.

[0074] After switching between forward stroke and reverse stroke, the front and rear main rocker arms are swapped, and the front and rear auxiliary arms are swapped. Therefore, the swing angles of the two main rocker arms need to be reset after each switch and before mining, thereby changing the heights of the front and rear main rocker arm drums and the front and rear auxiliary arm drums.

[0075] The diameter of the auxiliary arm roller is usually much smaller than the diameter of the main rocker arm roller.

[0076] When the front and rear main rocker arm rollers are cutting the top and bottom respectively, the front main rocker arm's suspension motor and the front auxiliary arm are suspended in the direction of the coal wall, which acts as a coal baffle. Although the front main rocker arm roller is located at the top, it can still load a small amount of coal. The rear main rocker arm roller, as the main loading roller, loads most of the coal. In addition to loading the coal mined by the knife into the conveying trough, the rear main rocker arm roller can also load the coal loaded by the front and rear auxiliary arm rollers and entering the main rocker arm roller channel of the knife into the conveying trough.

[0077] Furthermore, before mining, it is preferred to set the front end section of the auxiliary arm drum to be ahead of the front end section of the main rocker arm drum by half the main section depth (see Figure 9-11 ) or a main depth (see Figure 2 , 5 , 6, 7) and maintain this distance during mining, where half the main cutting depth is usually for poor roof conditions. It should be noted that the distance between the coal wall side end faces of the suspension motor and the main rocker arm roller of the main rocker arm where it is located should not be less than the difference between H and B.

[0078] The step length is usually equal to the distance of a main cutting depth.

[0079] The forward and reverse slots of each cutter are pre-slotted, and the upper and lower widths of the slots are as wide as possible. The purpose of pre-slotting is to provide passage space for the suspension motors of the front and rear main rocker arms of the next stroke. At the same time, the slotting also achieves a significant pre-splitting effect, which can significantly reduce the hardness of the coal seam, thus helping to reduce the cutting power consumption of the main rocker arm.

[0080] Furthermore, usually the lower groove mined in the current stroke should include the passage space for the suspension motor of the rear main rocker arm and the passage space for the rear auxiliary arm and its telescopic drive device when the rear main rocker arm roller mines the coal at the bottom of the groove in the next stroke, and leave a certain margin; the upper groove mined in the current stroke should include the passage space for the suspension motor of the front main rocker arm and the passage space for the front auxiliary arm and its telescopic drive device when the front main rocker arm roller mines the coal at the top of the groove in the next stroke, and leave a certain margin, or the superposition of the upper groove mined in the current stroke and the space cut out when the front main rocker arm roller mines the coal at the top of the groove in the next stroke should include the passage space for the suspension motor of the front main rocker arm and the passage space for the front auxiliary arm and its telescopic drive device when the front main rocker arm roller mines the coal at the top of the groove in the next stroke, and leave a certain margin.

[0081] The main rocker arm can be obtained through improved design based on the original matching rocker arm of the coal mining machine, which is equivalent to adding an auxiliary arm installation interface to the original rocker arm, and the original rocker arm structure and function are not affected.

[0082] Taking the right cutting part as an example, the main rocker arm housing 11 of the main rocker arm is provided with an auxiliary arm mounting hole 101 extending forward and backward, and the auxiliary arm is mounted on the main rocker arm housing with the help of a telescopic cylinder 4. The telescopic cylinder includes a cylinder 41 with two ends penetrating and a swing drive device mounting frame 42 cantilevered in front of the cylinder. The cylinder is inserted into the auxiliary arm mounting hole and forms a front and rear sliding fit with the main rocker arm housing. The swing drive device mounting frame is close to the main rocker arm roller in the left and right directions. The auxiliary arm housing 21 of the auxiliary arm includes an auxiliary arm arm frame 212 and a cylindrical front overhanging portion 213 and a cylindrical rear overhanging portion 211 extending forward and backward from the auxiliary arm arm frame respectively. The auxiliary arm arm frame is in the shape of a strip box that is flat and thin in front and back and extends left and right. The front overhanging portion and the rear overhanging portion are respectively close to the left and right ends of the auxiliary arm arm frame, and the auxiliary arm roller covers the radial outer side of the front overhanging portion. The rear overhanging portion is inserted into the cylinder from front to back and forms a rotational connection with the cylinder. In the installed state, the front overhanging portion is farther away from the main rocker arm roller than the rear overhanging portion in the left and right directions. The two ends of a swing drive oil cylinder 52 are respectively hinged on the swing drive device mounting frame and the auxiliary arm arm frame, and the hinge axes of the two hinges extend horizontally forward and backward. Driven by the extension of the swing drive oil cylinder, the auxiliary arm can swing around the axis of the cylinder. The change of the swing angle of the main rocker arm will cause the height of the main rocker arm roller and the auxiliary arm roller to change, and the swing of the auxiliary arm under the action of the swing drive oil cylinder can further change the height of the auxiliary arm roller, making the height adjustment of the auxiliary arm more flexible.

[0083] Therefore, on the basis of adjusting the swing angle of the main rocker arm, the swing angle of the auxiliary arm around the axis of the cylinder can be changed by controlling the extension and retraction of the swing drive cylinder, and the height of the corresponding auxiliary arm roller can be fine-tuned, thereby adjusting the height position relationship between the front and rear main rocker arm rollers and the front and rear auxiliary arm rollers.

[0084] Furthermore, one end of the swing drive oil cylinder can be hinged on the swing drive device mounting frame through the swing drive device telescopic cylinder end mounting seat 51, and the other end can be hinged on the top surface or bottom surface of the auxiliary arm frame through the swing drive device auxiliary arm end mounting seat 53, usually on the top surface, and the two hinge axes extend horizontally front and back. The swing drive device telescopic cylinder end mounting seat 51, the swing drive device auxiliary arm end mounting seat 53 and the swing drive oil cylinder 52 constitute the swing drive device 5. Since the auxiliary arm shell has a small height dimension, the swing drive device can be kept between the top surface and the bottom surface of the main rocker arm shell to prevent it from being damaged by the top roof and the bottom gangue.

[0085] Each set of the cutting parts also preferably includes a limit block 61, which is fixed on the mounting frame of the swing drive device. The limit block blocks the front of the rear overhang to prevent the rear overhang from escaping from the telescopic cylinder.

[0086] The auxiliary arm may also include an auxiliary arm motor 22, an auxiliary arm clutch 25 and an auxiliary arm transmission system 23. The auxiliary arm transmission system includes an auxiliary arm planetary reduction mechanism 232 and an auxiliary arm fixed axis gear transmission mechanism in transmission connection, and the auxiliary arm fixed axis gear transmission mechanism includes an input end gear 233, an idler gear and an output end gear 234 that are meshed in sequence. The inner cavity of the auxiliary arm frame is connected to the inner cavity of the front overhang and the rear overhang through the front bearing seat hole on the front side wall of the auxiliary arm frame and the rear bearing seat hole on the rear side wall, respectively, and the front bearing seat hole and the rear bearing seat hole are coaxial with the inner hole of the front overhang and the inner hole of the rear overhang, respectively. The front end opening of the front overhang is a power output port. The inner hole of the rear overhang includes an auxiliary arm planetary reduction mechanism mounting hole located in the front and an auxiliary arm motor mounting hole located in the rear. The auxiliary arm fixed-axis gear transmission mechanism is installed in the inner cavity of the auxiliary arm arm frame and the front overhang, wherein the output end of the auxiliary arm fixed-axis gear transmission mechanism is exposed in front of the front overhang and is coaxially connected to the auxiliary arm roller, and the auxiliary arm roller is covered on the radial outer side of the front overhang and does not contact the front overhang. The auxiliary arm planetary reduction mechanism and the auxiliary arm motor are installed in the inner hole of the rear overhang one after the other, and the output shaft of the auxiliary arm motor is coaxially connected and disconnected with the input end of the auxiliary arm planetary reduction mechanism through the auxiliary arm clutch, and the output end of the auxiliary arm planetary reduction mechanism is coaxially connected to the input end of the auxiliary arm fixed-axis gear transmission mechanism. The auxiliary arm motor provides power for the auxiliary arm transmission system.

[0087] The auxiliary arm housing preferably adopts a vertically symmetrical structure, so that the auxiliary arm housing has left-right interchangeability when installed on the main rocker arm housing. That is, the same auxiliary arm can be installed on the left main rocker arm, and can also be installed on the right main rocker arm after flipping. Further preferably, the auxiliary arm end mounting seat 53 of the swing drive device is installed at the vertically symmetrical position of the top and bottom surfaces of the auxiliary arm frame, and when the auxiliary arm housing is replaced left and right, one of the swing drive device auxiliary arm end mounting seats located on the top surface of the auxiliary arm frame can be activated.

[0088] The auxiliary arm motor preferably adopts a 6-pole or 8-pole multi-pole motor. The low-power configuration of the auxiliary arm has less impact on the configuration of the original main machine. Therefore, the difficulty of promoting and applying thin coal seam coal mining machines is greatly reduced and the prospects are good.

[0089] The auxiliary arm housing has a compact and simple structure overall and is more suitable for narrow space operations underground in thin coal seams.

[0090] The main rocker arm housing is also provided with a telescopic drive device mounting hole 103 extending forward and backward, and the auxiliary arm mounting hole is connected to the telescopic drive device mounting hole from left to right. The telescopic drive device is mounted in the telescopic drive device mounting hole, and the two ends of the telescopic drive device are respectively connected to the inner wall of the telescopic drive device mounting hole and the outer cylindrical surface of the cylinder body facing the telescopic drive device mounting hole. Driven by the telescopic drive device, the telescopic cylinder together with the auxiliary arm slides forward and backward relative to the main rocker arm housing.

[0091] The telescopic drive device may include a telescopic drive device main rocker arm end mounting seat 31, a telescopic drive device auxiliary arm end mounting seat 33 and a telescopic oil cylinder 32. The telescopic drive device main rocker arm end mounting seat is mounted on the inner wall of the telescopic drive device mounting hole, the telescopic drive device auxiliary arm end mounting seat is mounted on the outer cylindrical surface of the cylinder body facing the telescopic drive device mounting hole, and the two ends of the telescopic oil cylinder are respectively hinged to the telescopic drive device main rocker arm end mounting seat and the telescopic drive device auxiliary arm end mounting seat. The combination of the auxiliary arm and the telescopic cylinder slides forward and backward relative to the main rocker arm housing under the telescopic drive of the telescopic oil cylinder.

[0092] An anti-rotation structure is provided at the joint of the cylinder and the main rocker arm housing to ensure the linear movement of the cylinder relative to the main rocker arm housing. The anti-rotation structure can have the following two structural types: 1) The cross-sectional profiles of the auxiliary arm mounting hole and the outer cylindrical surface of the cylinder are both circular, and the top surface and the bottom surface of the left and right connecting points of the auxiliary arm mounting hole and the telescopic drive device mounting hole are respectively set as upper guide surfaces and lower guide surfaces 102, and a guide strip extending in the front-to-back direction is fixed on the side of the outer cylindrical surface of the cylinder facing the telescopic drive device mounting hole, and the upper and lower side surfaces 331 of the guide strip are respectively fitted with the upper and lower guide surfaces to achieve guidance and anti-rotation during the forward and backward movement of the telescopic cylinder. 2) The cross-sectional profiles of the auxiliary arm mounting hole and the outer cylindrical surface of the cylinder are both rectangular, and the sliding matching structure of the cylinder and the main rocker arm housing itself has the guiding and anti-rotation functions, so the structure is simpler.

[0093] When the anti-rotation structure adopts the structural type 1), the mounting seat at the end of the auxiliary arm of the telescopic drive device is preferably fixedly connected to the guide bar to form a whole (see Fig. 22 ), in order to facilitate the installation of the guide strip, a flat-bottomed groove of corresponding shape and size can be provided on the outer cylindrical surface of the cylinder to provide an installation reference surface for the guide strip.

[0094] The main rocker arm housing is also provided with a main rocker arm transmission mechanism installation cavity 114 and a main rocker arm motor installation hole 113 extending forward and backward. The auxiliary arm installation hole 101, the telescopic drive device installation hole 103, the main rocker arm motor installation hole 113 and the main rocker arm transmission mechanism installation cavity 114 are arranged in sequence from the fuselage connection end to the drum installation end in the left and right direction. For the suspended motor rocker arm, the main rocker arm transmission mechanism installation cavity partially extends to the rear of the main rocker arm motor installation hole. The front hole wall of the main rocker arm motor installation hole is the overhanging section hole wall (also called the protective edge 105, which can protect the auxiliary arm) that overhangs forward beyond the auxiliary arm installation hole, the telescopic drive device installation hole and the main rocker arm transmission mechanism installation cavity to adapt to the assembly of the main rocker arm of the "suspended motor" structure. The main rocker arm housing can be either an integrated structure or a split structure.

[0095] The main rocker arm is also provided with a main rocker arm motor 12, a main rocker arm clutch 17 and a main rocker arm transmission mechanism 13. The main rocker arm transmission mechanism includes a main rocker arm fixed-axis gear transmission mechanism and a main rocker arm planetary reduction mechanism 132. The main rocker arm motor and the main rocker arm fixed-axis gear transmission mechanism are respectively installed in the main rocker arm motor installation hole and the main rocker arm transmission mechanism installation cavity. The main rocker arm planetary reduction mechanism is installed on the outer side of the front cavity wall of the main rocker arm transmission mechanism installation cavity. The output shaft of the main rocker arm motor is arranged toward the rear and is coaxially connected and disconnected with the input end of the main rocker arm fixed-axis gear transmission mechanism through the main rocker arm clutch. The output end of the main rocker arm fixed-axis gear transmission mechanism is coaxially connected to the input end of the main rocker arm planetary reduction mechanism. The main rocker arm roller is coaxially fixedly connected with the output end of the main rocker arm planetary reduction mechanism through a square connecting sleeve. The main rocker arm roller covers the outer side of the main rocker arm planetary reduction mechanism from front to back, and the main rocker arm roller does not contact the main rocker arm planetary reduction mechanism.

[0096] The fuselage connection end of the main rocker arm housing is provided with a fuselage articulated seat 111 located at the upper part and a height adjustment cylinder articulated seat 112 located at the lower part, which are respectively used for the articulation of the main rocker arm housing with the fuselage and the height adjustment cylinder. The swing drive cylinder is preferably located between the end section of the main rocker arm drum on the goaf side and the front end surfaces of the fuselage articulated seat and the height adjustment cylinder articulated seat, and a certain safety distance is left so that the swing drive cylinder does not interfere with the bottom coal platform and the main rocker arm housing. When the auxiliary arm housing is at the end of the rear end stroke of the forward and backward sliding, the auxiliary arm boom in the forward and backward direction is preferably located between the end section of the main rocker arm drum on the goaf side and the front end surfaces of the fuselage articulated seat and the height adjustment cylinder articulated seat, and has good adaptability to the bottom unmined coal platform.

[0097] Whether it is the main rocker arm or the auxiliary arm, the structure and installation of the motor, clutch, transmission mechanism (including reduction mechanism) and roller, etc. can be achieved by adopting or drawing on the existing rocker arm structure.

[0098] The use of "left, right, front, back, up and down" in the above-mentioned description of the relevant structure of the coal mining machine is to express the relative position relationship between the corresponding structures, and is not a limitation on their absolute positions. The left and right are borrowed from the traction direction of the coal mining machine when it is working, and the front is the direction pointing vertically to the coal wall.

Claims

1. A thin coal seam pre-slotting mining method suitable for a wide mining range, characterized by: Mining is carried out using a drum-type coal mining machine including two sets of left and right cutting parts. Each set of cutting parts includes a main rocker arm, an auxiliary arm and a telescopic drive device. The main rocker arm and the auxiliary arm have their own independent power systems. One end of the main rocker arm is hinged on the body of the coal mining machine, and the other end is equipped with a main rocker arm drum. The main rocker arm changes its swing angle by telescoping the height adjustment cylinder connected between the main rocker arm and the body. The main rocker arm adopts a suspended motor rocker arm, and an auxiliary arm drum is installed at the front end of the auxiliary arm. The rear part of the auxiliary arm is installed on the main rocker arm housing of the main rocker arm and cooperates with the main rocker arm housing to slide back and forth. The auxiliary arm can slide back and forth relative to the main rocker arm under the drive of the telescopic drive device. The cutting width of the auxiliary arm drum is not less than the cutting width of the main rocker arm drum, and the auxiliary arm is at the rear end of the forward and backward sliding stroke. When the front end section of the auxiliary arm drum is flush with the front end section of the main rocker arm drum, when the auxiliary arm is at the front end of the forward and backward sliding stroke, the front end section of the auxiliary arm drum is ahead of the front end section of the main rocker arm drum by a distance not less than the cutting width of the main rocker arm drum; the coal mining machine moves back and forth along the working face left and right, and mining is one cut. The corresponding stroke includes the forward stroke and the reverse stroke in sequence. The main rocker arms in front and rear of the walking direction are respectively called the front main rocker arm and the rear main rocker arm, and the auxiliary arms in front and rear of the walking direction are respectively called the front auxiliary arm and the rear auxiliary arm. Before mining, the front end section of the auxiliary arm drum is set to be ahead of the front end section of the main rocker arm drum by a distance and maintained during the mining process. The distance is taken between (0,1] times the main cutting depth. The mining process is: The first cutter forward stroke mining: the two main rocker arms do not participate in mining, the front and rear auxiliary arm rollers respectively groove upward and groove downward and form upper grooves and lower grooves respectively, and the upper grooves and lower grooves are superimposed to form the first cutter forward groove; The first knife reverse stroke mining: the coal mining machine moves one step distance along with the conveyor and the support toward the direction close to the coal wall, and the front and rear main rocker arm rollers respectively mine the coal at the top and bottom of the slot opened by the first knife forward, while the front and rear auxiliary arm rollers respectively open slots upward and downward to form upper and lower slots respectively, and the upper and lower slots are superimposed to form the first knife reverse slot; The second knife forward stroke mining: the coal mining machine moves one step distance in the direction close to the coal wall along with the conveyor and the support, and the front and rear main rocker arm rollers respectively mine the coal at the top and bottom of the slot opened by the first knife in reverse, while the front and rear auxiliary arm rollers respectively open the slot upward and downward to form the upper slot and the lower slot respectively, and the upper slot and the lower slot are superimposed to form the second knife forward slot; The second knife reverse stroke mining: the coal mining machine moves one step distance along with the conveyor and the support toward the direction close to the coal wall, and the front and rear main rocker arm rollers respectively mine the coal at the top and bottom of the slot opened by the second knife in the forward direction, while the front and rear auxiliary arm rollers respectively open slots upward and downward to form the upper slot and the lower slot respectively, and the upper slot and the lower slot are superimposed to form the reverse slot opened by the second knife; Continue the subsequent mining in a reciprocating manner according to the second mining method; The lower slot mined in the current stroke should include the passage space of the suspension motor of the rear main rocker arm and the passage space of the rear auxiliary arm and its telescopic drive device when the rear main rocker arm roller mines the coal at the bottom of the slot in the next stroke; the upper slot mined in the current stroke should include the passage space of the suspension motor of the front main rocker arm and the passage space of the front auxiliary arm and its telescopic drive device when the front main rocker arm roller mines the coal at the top of the slot in the next stroke, or the superposition of the upper slot mined in the current stroke and the space cut out when the front main rocker arm roller mines the coal at the top of the slot in the next stroke should include the passage space of the suspension motor of the front main rocker arm and the passage space of the front auxiliary arm and its telescopic drive device when the front main rocker arm roller mines the coal at the top of the slot in the next stroke; The lowest point of the main rocker arm roller before the current stroke is not higher than the upper section of the upper groove mined in the previous stroke, and the lowest point of the front auxiliary arm roller in the same stroke is not higher than the highest point of the rear auxiliary arm roller.

2. The thin coal seam pre-slotting mining method suitable for a wide mining range as claimed in claim 1, characterized in that: The diameter of the auxiliary arm roller is smaller than the diameter of the main rocker arm roller.

3. The thin coal seam pre-slotting mining method suitable for a wide mining range as claimed in claim 1, characterized in that: When the front and rear main rocker arm rollers mine the coal at the top and bottom of the trough respectively, the front main rocker arm roller loads a small amount of coal, and the rear main rocker arm roller loads most of the coal.

4. The thin coal seam pre-slotting mining method suitable for a wide mining range as claimed in claim 1, characterized in that: Before mining, the front end section line of the auxiliary arm drum is set to be ahead of the front end section line of the main rocker arm drum by half the main cutting depth or one main cutting depth and this distance is maintained during the mining process.

5. The thin coal seam pre-slotting mining method suitable for a wide mining range as claimed in claim 1, characterized in that: The step length is equal to the distance of a main cutting depth.

6. The thin coal seam pre-slotting mining method suitable for a wide mining range as claimed in claim 1, characterized in that: The lower groove mined in the current stroke should include the passage space for the suspension motor of the rear main rocker arm and the passage space for the rear auxiliary arm and its telescopic drive device when the rear main rocker arm roller mines the coal at the bottom of the groove in the next stroke, and leave a certain margin; the upper groove mined in the current stroke should include the passage space for the suspension motor of the front main rocker arm and the passage space for the front auxiliary arm and its telescopic drive device when the front main rocker arm roller mines the coal at the top of the groove in the next stroke, and leave a certain margin, or the superposition of the upper groove mined in the current stroke and the space cut out when the front main rocker arm roller mines the coal at the top of the groove in the next stroke should include the passage space for the suspension motor of the front main rocker arm and the passage space for the front auxiliary arm and its telescopic drive device when the front main rocker arm roller mines the coal at the top of the groove in the next stroke, and leave a certain margin.

7. The thin coal seam pre-slotting mining method adapted to a wide mining range as claimed in claim 1, 2, 3, 4, 5 or 6, characterized in that: The main rocker arm housing of the main rocker arm is provided with an auxiliary arm mounting hole extending forward and backward. The auxiliary arm is mounted on the main rocker arm housing with the help of a telescopic cylinder. The telescopic cylinder includes a cylinder body with two ends penetrating therethrough and a swing drive device mounting frame cantilevered in front of the cylinder body. The cylinder body is inserted into the auxiliary arm mounting hole and forms a front and rear sliding fit with the main rocker arm housing. The swing drive device mounting frame is close to the main rocker arm drum in the left and right directions. The auxiliary arm housing of the auxiliary arm includes an auxiliary arm frame and a cylindrical front overhanging portion and a cylindrical rear overhanging portion extending forward and backward respectively from the auxiliary arm frame. The auxiliary arm frame is in the shape of a strip box that is flat and thin front and back and extends left and right. The front overhanging portion and the rear overhanging portion are respectively close to the main rocker arm drum. At the left and right ends of the auxiliary arm frame, the auxiliary arm rollers are covered on the radial outer side of the front overhang, and the rear overhang is inserted into the cylinder from front to rear and forms a rotational connection with the cylinder. In the left and right directions, the front overhang is farther away from the main rocker arm roller than the rear overhang; the two ends of a swing drive cylinder are respectively hinged on the swing drive device mounting frame and the auxiliary arm frame, and the hinge axes of the two hinges extend horizontally front and back. Driven by the extension and contraction of the swing drive cylinder, the auxiliary arm can swing around the axis of the cylinder; on the basis of adjusting the swing angle of the main rocker arm, the swing angle of the auxiliary arm around the axis of the cylinder is changed by controlling the extension and contraction of the swing drive cylinder, and the height of the corresponding auxiliary arm roller is fine-tuned.

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