Automatic tensioning method and tensioning system for scraper chain of transport mechanism of tunnel boring machine

Abstract

The present invention discloses an automatic tensioning method and tensioning system for a scraper chain of a roadheader transport mechanism, comprising the following steps: 1. Starting the roadheader and starting adjustment; 2. Using a machine body inclination sensor to monitor the actual inclination angle α1 of the machine body in real time; when α1 is within the range of [-X, X], directly starting to tension the conveyor chain; and checking whether a proximity switch detects the conveyor chain. If not, adjustment ends; if the conveyor chain is detected, detecting the value of a tensioning stroke sensor; if the tensioning cylinder has not reached its maximum stroke, gradually extending the tensioning cylinder at a certain step distance H0 until the conveyor chain leaves the detection range of the proximity switch, and tensioning ends; otherwise, when it is detected that the tensioning cylinder has extended to its maximum, tensioning reaches its maximum stroke, and tensioning ends. The present invention can realize automatic tensioning of the conveyor chain after the roadheader is started, so that the conveyor chain always operates at a normal tension.

Description

Technical Field

[0001] The invention belongs to the technical field of automatic control of coal mine heading equipment, and in particular relates to an automatic tensioning method and a tensioning system for a scraper chain of a conveying mechanism of a roadheader. Background Art

[0002] The conveyor chain on the roadheader's transport mechanism is mainly used to transport materials cut by the roadheader's cutting head. Long-term operation will cause wear between the chain links of the conveyor chain, resulting in an increase in the pitch of the conveyor chain. At the same time, the conveyor chain is an elastic body and will be subjected to tension and elastic elongation during operation. These two working conditions will increase the length of the entire conveyor chain of the roadheader, causing the conveyor chain to become loose and the overhang below the drive sprocket to increase. When the overhang increases to a certain extent, it is very easy to cause faults such as chain jamming and chain jumping.

[0003] At present, the conveying chains on domestic tunnel boring machines have not yet achieved automatic tensioning, and mainly rely on regular inspections by workers. When the chain of the transport mechanism is observed to be loose, the operator controls the telescopic handle of the tensioning cylinder to tension it. If the workers do not check in time, when the chain loosens to a certain extent, it is very likely that severe conditions such as chain jamming and chain jumping will occur, affecting the transportation of the conveying mechanism and thus affecting the shipping efficiency. In severe cases, the tunneling working face will be shut down. Summary of the Invention

[0004] In order to solve the above technical problems, the present invention provides an automatic tensioning method and tensioning system for a scraper chain of a roadheader transport mechanism.

[0005] The present invention provides a method for automatically tensioning a scraper chain of a roadheader transport mechanism, comprising the following steps:

[0006] Step 1: Start the tunnel boring machine and start adjustment;

[0007] Step 2: Use the machine body inclination sensor to monitor the actual inclination angle α1 of the machine body in real time. When α1 is within the range of [-X, X], start tightening the conveyor chain directly. The specific steps are as follows:

[0008] Check whether the proximity switch detects the conveyor chain. If not, the adjustment is completed. If the conveyor chain is detected, check the value of the tensioning stroke sensor. If the tensioning cylinder has not reached the maximum stroke, the tensioning cylinder will be gradually extended at a certain step distance H0 until the conveyor chain is out of the detection range of the proximity switch. At this time, the conveyor chain is tensioned to the appropriate tightness and the tensioning is completed. Otherwise, when it is detected that the tensioning cylinder is extended to the longest, the tensioning reaches the maximum stroke and the tensioning is completed. Check whether the conveyor adjustment cylinder is at the initial length Lt by adjusting the cylinder stroke sensor. If not, adjust the conveyor adjustment cylinder to the initial length.

[0009] Further, including step 3, when it is detected that α1 is within the range of [-Y, -X) or (X, Y], the inclination angle of the machine body is adjusted by adjusting the rear support cylinder or the loading cylinder. When the inclination angle of the machine body reaches a certain range, the conveyor chain is tightened. The specific steps are as follows:

[0010] Step 3.1: When α1 is detected to be within the range of [-Y, -X), the rear support cylinder is retracted to its shortest position, and the loading cylinder is gradually extended at a certain step distance L2 until the inclination angle of the machine body is detected to be within the range of [-X, X]. At this time, the inclination angle adjustment of the machine body is completed, and the conveyor chain is tensioned according to step 2;

[0011] Step 3.2: When α1 is detected to be within the range of [X, Y], the loading cylinder is shortened to its minimum and the rear support cylinder is gradually extended at a certain step distance L1 until the inclination angle of the machine body is detected to be within the range of [-X, X]. At this time, the inclination angle adjustment of the machine body is completed and the conveyor chain is tensioned according to step 2.

[0012] Furthermore, the method includes step 4, using a conveyor inclination sensor to monitor the actual inclination angle α2 of the transport mechanism in real time. When it is detected that α1 is within the range of [-K, -Y) or (Y, K], the inclination angle of the machine body is adjusted by adjusting the rear support cylinder and the loading cylinder, and then the inclination angle of the transport mechanism is adjusted by adjusting the conveyor adjustment cylinder. When the inclination angle of the transport mechanism reaches a certain range, the conveyor chain is tightened. The specific steps are as follows:

[0013] Step 4.1: When α1 is detected to be within the range of [-K, -Y), the loading cylinder is extended to its maximum and the rear support cylinder is retracted to its minimum. The inclination angle of the machine body is then checked to see if it is within the range of [-X, X]. If so, the adjustment is complete. If not, the conveyor adjustment cylinder is gradually shortened by a certain step length L0 until the conveyor mechanism inclination angle is detected to be within the range of [-β1-c, β1+c], where β1 is the initial inclination angle of the conveyor mechanism and c is a certain tolerance value. At this point, the conveyor mechanism inclination angle adjustment is complete and the conveyor chain is tensioned according to step 2.

[0014] Step 4.2: When it is detected that α1 is within the range of [Y, K], the rear support cylinder is extended to the maximum and the loading cylinder is retracted to the minimum. At this time, the inclination angle of the machine body is detected to be within the range of [-X, X]. If it is within this range, the adjustment is completed. If not, the conveyor adjustment cylinder is gradually extended with a certain step distance L0 until the inclination angle of the conveyor mechanism 4 is detected to be within the range of [-β1-c, β1+c]. At this time, the conveyor mechanism inclination adjustment is completed and the conveyor chain is tensioned according to step 2.

[0015] Furthermore, the method includes step 5: when it is detected that α1<-k or α1>k, the adjustment range is exceeded and the adjustment is ended.

[0016] Furthermore, K is the maximum inclination angle of the machine body that can be achieved by adjusting the angle of the transport mechanism through the conveyor adjustment cylinder.

[0017] The present invention also provides a scraper chain tensioning system of a tunnel boring machine transportation mechanism, including a machine body, a loading oil cylinder, a rear support leg and a transportation mechanism. The loading oil cylinder is hingedly connected to the front end of the machine body. The loading oil cylinder is also connected to the machine body through the loading oil cylinder to adjust the angle of the loading oil cylinder. The telescopic action of the loading oil cylinder makes the loading oil cylinder contact the ground to adjust the inclination angle of the machine body. Rear support legs are provided on both sides of the rear end of the machine body. The rear support legs are connected to the machine body through the rear support cylinder. The rear support legs support the ground through the telescopic action of the rear support legs to adjust the inclination angle of the machine body. The transportation mechanism includes a conveyor body, a driving mechanism, a chain tensioning mechanism and a conveying chain. A body inclination sensor is horizontally installed on the machine body for measuring the actual inclination angle of the machine body. A proximity switch is provided at the return chain near the bottom of the driving mechanism of the conveying chain. When the conveying chain is loose and is in the detection range of the proximity switch, the chain tensioning mechanism works, and the conveying chain starts to be tensioned until the conveying chain leaves the detection range of the proximity switch.

[0018] Furthermore, the front end of the conveyor body is hinged to the loading mechanism or the body, and the rear end of the conveyor body is connected to the rear end of the body through a conveyor adjustment cylinder. The conveyor body is raised or lowered by extending and shortening the conveyor adjustment cylinder. A conveyor inclination sensor is installed on the conveying surface of the conveyor body parallel to the conveyor body to measure the actual inclination of the conveying mechanism.

[0019] Furthermore, the rear supporting legs are hingedly connected to the body.

[0020] Furthermore, the chain tensioning mechanism includes a tensioning oil cylinder and a buffer device, and a tensioning stroke sensor is installed in the tensioning oil cylinder for measuring the actual stroke of the tensioning oil cylinder.

[0021] Furthermore, the loading cylinder is equipped with a loading cylinder stroke sensor, the rear supporting cylinder is equipped with a rear supporting cylinder stroke sensor, and the conveyor adjusting cylinder is equipped with an adjusting cylinder stroke sensor.

[0022] The present invention has the following effects compared to the prior art:

[0023] The automatic tensioning method and tensioning system of the scraper chain of the tunnel boring machine transportation mechanism of the present invention can realize the automatic tensioning of the conveyor chain after the tunnel boring machine is started, so that the conveyor chain always works at a normal tightness, effectively solving the problems of chain jamming and chain jumping caused by the conveyor chain being too loose, ensuring the continuity of the shipping work, and improving the shipping efficiency of the rock tunnel boring machine. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a front view of the scraper chain tensioning system of the roadheader transport mechanism of the present invention;

[0025] Figure 2 A cross-sectional view of the transport mechanism in the scraper chain tensioning system of the roadheader transport mechanism of the present invention;

[0026] Figure 3 This is an isometric view of the drive mechanism and chain tensioning mechanism in the scraper chain tensioning system of the roadheader transport mechanism of the present invention;

[0027] Figure 4 A schematic diagram of the tensioning state of the conveying chain in the scraper chain tensioning system of the roadheader transport mechanism of the present invention;

[0028] Figure 5 This is a flow chart of the method for automatically tensioning the scraper chain of the roadheader transport mechanism of the present invention;

[0029] Figure 6 This is a flow chart of the machine body inclination adjustment in the method for automatically tensioning the scraper chain of the roadheader transport mechanism of the present invention;

[0030] Figure 7 The present invention is a flow chart of the inclination adjustment of the transport mechanism in the automatic tensioning method of the scraper chain of the transport mechanism of the tunnel boring machine.

[0031] In the figure: 1-loading mechanism; 2-loading cylinder; 21-loading cylinder stroke sensor; 3-machine body; 31-machine body inclination sensor; 32-connecting loading kingpin hole; 33-connecting rear support kingpin hole; 4-transportation mechanism; 41-conveyor body; 42-driving mechanism; 43-chain tensioning mechanism; 431-tensioning cylinder; 4311-tensioning stroke sensor; 432-buffer device; 44-conveyor chain; 45-proximity switch; 46-conveyor inclination sensor; 5-rear support leg; 6-rear support cylinder; 61-rear support cylinder stroke sensor; 7-conveyor adjustment cylinder; 71-adjustment cylinder stroke sensor; 8-travel mechanism. DETAILED DESCRIPTION

[0032] In order to better understand the purpose, structure and function of the present invention, the following is a further detailed description of an automatic tensioning method and tensioning system for a scraper chain of a roadheader transport mechanism of the present invention in conjunction with the accompanying drawings.

[0033] like Figure 1 As shown, a scraper chain tensioning system of a roadheader transport mechanism includes a body 3, a charging mechanism 1, a rear support leg 5 and a transport mechanism 4. The body 3 is equipped with a body inclination sensor 31, which is installed horizontally to measure the actual inclination of the body 3; Figure 1 View and placement position, when the body inclination sensor 31 rotates counterclockwise, the inclination angle α1 of the body 3 is a negative value, and when the body inclination sensor 31 rotates clockwise, the inclination angle α1 of the body 3 is a positive value.

[0034] One end of the loading mechanism 1 is hinged to the machine body 3, and the other end of the loading mechanism 1 is connected to the machine body 3 through the loading cylinder 2. The loading mechanism 1 can rotate around the central axis of the main loading pin hole 32 of the machine body 3 through the extension and contraction of the loading cylinder 2; specifically, when the loading cylinder 2 is extended, the loading mechanism 1 rotates counterclockwise around the central axis of the main loading pin hole 32, that is, the front end shovel tip of the loading mechanism 1 moves downward; when the loading cylinder 2 is shortened, the loading mechanism 1 rotates clockwise around the central axis of the main loading pin hole 32, that is, the front end shovel tip of the loading mechanism 1 moves upward; a loading cylinder stroke sensor 21 is installed inside the loading cylinder 2 to measure the stroke of the loading cylinder 2.

[0035] The rear support legs 5 are symmetrically arranged on the left and right sides of the rear end of the body part 3. One end of the rear support leg 5 is hinged to the body part 3, and the other end of the rear support leg 5 is connected to the body part 3 through the rear support cylinder 6. The rear support leg 5 can rotate around the central axis of the rear support main pin hole 33 connected to the body part 3 through the extension and contraction of the rear support cylinder 6; specifically, when the rear support cylinder 6 is extended, the rear support leg 5 rotates clockwise around the central axis connected to the rear support main pin hole 33, that is, the rear end of the rear support leg 5 moves downward; when the rear support cylinder 6 is shortened, the rear support leg 5 rotates counterclockwise around the central axis connected to the rear support main pin hole 33, that is, the rear end of the rear support leg 5 moves upward; a rear support cylinder stroke sensor 61 is installed inside the rear support cylinder 6 to measure the stroke of the rear support cylinder 6.

[0036] Specifically, when the loading cylinder 2 of the tunnel boring machine is extended to its maximum stroke, the front shovel tip of the loading mechanism 1 remains grounded with the rear end of the traveling mechanism 8, causing the tunnel boring machine to have a clockwise inclination angle greater than 3° and less than 4°; when the rear support cylinder 6 is extended to its maximum stroke, the rear end of the rear support leg 5 remains grounded with the front end of the traveling mechanism 8, causing the tunnel boring machine to have a counterclockwise inclination angle greater than 3° and less than 4°.

[0037] like Figures 2 to 4As shown, the transport mechanism 4 includes a conveyor body 41, a driving mechanism 42, a chain tensioning mechanism 43, a conveying chain 44, a proximity switch 45 and a conveyor inclination sensor 46. The front end of the conveyor body 41 is hinged to the loading mechanism 1 or the body 3, and the rear end of the conveyor body 41 is connected to the rear end of the body 3 through the conveyor adjustment cylinder 7. The extension and contraction of the conveyor adjustment cylinder 7 realizes the counterclockwise (raising) or clockwise (lowering) rotation of the conveyor body 41; the conveyor inclination sensor The device 46 is installed parallel to the conveyor body 41, specifically, the conveyor inclination sensor 46 is parallel to the conveying surface 411, and is used to measure the actual inclination angle α2 of the conveying mechanism 4; the initial length of the conveyor adjustment cylinder 7 is Lt, and the initial inclination angle |α2| (the absolute value of α2) of the conveying mechanism 4 is β1; the driving mechanism 42, the chain tensioning mechanism 43 and the conveying chain 44 constitute the tensioning system of the conveying chain of the conveying mechanism, and the conveying chain 44 is wrapped around the loading mechanism 1 and the conveyor body 41.

[0038] The specific tensioning method is: when the conveying chain 44 is relaxed, the tensioning cylinder 431 of the driving chain tensioning mechanism 43 is extended. Through the extension of the tensioning cylinder 431, the chain tensioning mechanism 43 pushes the driving mechanism 43 to move backward, so that the installation center distance of the conveying chain 44 is lengthened, and finally the conveying chain 44 is tensioned.

[0039] The chain tensioning mechanism 43 includes a tensioning cylinder 431 and a buffer device 432; a tensioning stroke sensor 4311 is installed in the tensioning cylinder 431 for measuring the actual stroke of the tensioning cylinder 431. When the tensioning cylinder 431 is extended to the maximum stroke, it indicates that the conveying chain 44 cannot be tensioned by the chain tensioning mechanism 43 any further, and it is necessary to continue tensioning by reducing the length of the conveying chain 44. The total stroke H of the tensioning cylinder 431 is generally 150mm, which means that the installation center distance of the conveying chain 44 can be lengthened by a maximum of 150mm, that is, the maximum tensioning of the conveying chain 44 within a range of 300mm due to wear and other reasons can be met. The normal tightness of the conveying chain 44 of the cantilever tunneling machine is generally expressed as follows: the maximum sag L of the conveying chain 44 at the chain return below the driving mechanism 42 is no more than 70mm, from Figure 4 It can be seen that when the conveyor chain 44 is at an appropriate tension, the center distance of the conveyor chain 44 installation is within a range of 0-150mm. The bottom surface of the conveyor chain will always pass through certain locations on the chain return. Proximity switches 45 are installed a certain distance Lp below these locations. This allows for the minimum number of proximity switches 45 to be arranged. Preferably, proximity switches 45 are installed symmetrically on both sides of the conveyor mechanism 4, so that the tension of the conveyor chain 44 on one side can be independently controlled. When the conveyor chain 44 is slack and within the detection range of the proximity switch 45, the tensioning cylinder 431 is activated, and the conveyor chain 44 begins to tighten until the conveyor chain leaves the detection range of the proximity switch 45.

[0040] The tensioning of the conveyor chain 44 must be carried out during the initialization phase of the entire machine startup, and cannot be carried out during the normal operation phase of the transport mechanism 4. During the operation phase of the transport mechanism 4, since the upper chain of the conveyor chain 44 is in a tensioned state, there will be a large slack at the return chain. At this time, there will inevitably be a large error in tensioning the conveyor chain 44.

[0041] like Figures 5 to 7 As shown, this embodiment provides a method for automatically tensioning a scraper chain of a roadheader transport mechanism, comprising the following steps:

[0042] 1. Start the tunnel boring machine and begin adjustments.

[0043] 2. Use the machine body inclination sensor 31 to monitor the actual inclination angle α1 of the machine body 3 in real time. When α1 is within the range of [-1, 1], start directly tightening the conveyor chain 44. On the one hand, when the machine body 3 changes within the range of -1° to 1°, it has little effect on the direction of the conveyor chain 44 at the chain return. On the other hand, maintaining a certain adjustment tolerance is more conducive to the adjustment of the conveyor chain 44. The specific steps are as follows:

[0044] 2.1. Check whether the proximity switch 45 is connected. In this embodiment, the proximity switch 45 is normally open. When the conveyor chain 44 is not detected, the proximity switch 45 is in the off state. When the conveyor chain 44 is detected, the proximity switch 45 is in the on state. A normally closed proximity switch 45 can also be selected. When it is not connected, the adjustment is completed;

[0045] 2.2. When the proximity switch 45 is in the on state, the value of the tensioning stroke sensor 4311 is detected. If the tensioning cylinder 431 has not reached its maximum stroke, the tensioning cylinder 431 will gradually extend at a certain step distance H0 until the proximity switch 45 is detected to be disconnected. At this time, the conveyor chain 44 is tensioned to the appropriate tension and tensioning is completed. Otherwise, when the tensioning cylinder 431 is detected to be extended to the maximum, the tensioning reaches the maximum stroke and tensioning is completed.

[0046] 2.3. Check whether the conveyor adjusting cylinder 7 is at the initial length Lt by adjusting the cylinder stroke sensor 71. If not, adjust the conveyor adjusting cylinder 7 to the initial length.

[0047] 3. When it is detected that α1 is within the range of [-3, -1) or (1, 3], the inclination angle of the machine body 3 is adjusted by adjusting the rear support cylinder 6 or the charging cylinder 2. When the inclination angle of the machine body 3 reaches a certain range, the conveyor chain 44 is tightened. The specific steps are as follows:

[0048] 3.1. When α1 is detected to be within the range of [-3, -1), the rear support cylinder 6 is shortened to its shortest position, and the loading cylinder 2 is gradually extended at a certain step distance L2 until the inclination angle of the machine body 3 is detected to be within the range of [-1, 1]. At this point, the inclination angle adjustment of the machine body 3 is completed, and the conveyor chain is tensioned according to step 2;

[0049] 3.2. When α1 is detected to be within the range of (1, 3], the loading cylinder 2 is shortened to its minimum and the rear support cylinder 6 is gradually extended at a certain step distance L1 until the inclination angle of the machine body 3 is detected to be within the range of [-1, 1]. At this time, the inclination angle adjustment of the machine body 3 is completed and the conveyor chain is tensioned according to step 2.

[0050] 4. When it is detected that α1 is within the range of [-K, -3) or (3, K], the inclination of the machine body 3 is adjusted by adjusting the rear support cylinder 6 and the loading cylinder 2, and the inclination of the transport mechanism 4 is adjusted by adjusting the conveyor adjustment cylinder 7. When the inclination of the transport mechanism 4 reaches a certain range, the conveyor chain 44 is tightened. K is a positive value, and the K value is determined according to the angle change of the transport mechanism 4 that can be achieved by the conveyor adjustment cylinder 7. The specific steps are as follows:

[0051] 4.1. When α1 is detected to be within the range of [-K, -3), the loading cylinder 2 is extended to its maximum and the rear support cylinder 6 is retracted to its minimum. The inclination angle of the machine body 3 is then checked to see if it is within the range of [-1, 1]. If so, the adjustment is complete. If not, and |α2| > β1, the conveyor adjustment cylinder 7 is gradually shortened at a certain step length L0 until the inclination angle of the conveyor mechanism 4 is detected to be within the range of [-β1-c, β1+c] (β1 is the initial inclination angle of the conveyor mechanism 4, and c is a certain tolerance value, both of which are positive). At this point, the inclination adjustment of the conveyor mechanism 4 is complete, and the conveyor chain is tensioned according to step 2.

[0052] 4.2. When α1 is detected to be within the range of (3, K], the rear support cylinder 6 is extended to its maximum extent and the loading cylinder 2 is retracted to its minimum extent. The inclination angle of the machine body 3 is then detected to be within the range of [-1, 1]. If so, the adjustment is complete. If not, and |α2| < β1, the conveyor adjustment cylinder 7 is gradually extended at a certain step length L0 until the inclination angle of the conveyor mechanism 4 is detected to be within the range of [-β1-c, β1+c]. At this point, the inclination adjustment of the conveyor mechanism 4 is complete, and the conveyor chain is tensioned according to step 2.

[0053] 5. When it is detected that α1<-k or α1>k, it is out of the adjustment range and the adjustment is ended.

[0054] Because the position of the proximity switch 45 is fixed on the conveyor mechanism 4, and changes in the actual inclination of the conveyor mechanism 4 will inevitably affect the drooping shape of the conveyor chain 44 at the chain return, that is, the direction of the conveyor chain at the chain return, which will affect the detection of the proximity switch 45, the present invention is based on maintaining the initial inclination angle β1 of the conveyor mechanism 4 relative to the horizontal ground unchanged during conveyor chain 44 tensioning. Therefore, much of the work of the present invention is to ultimately ensure that the initial inclination angle β1 of the conveyor mechanism 4 relative to the horizontal ground is maintained unchanged before the conveyor chain 44 is tensioned by adjusting the inclination of the body 3 and the inclination of the conveyor mechanism 4. The overall concept of this method is: first adjust the inclination of the conveyor mechanism 4, and then tension the conveyor chain 44.

[0055] It will be understood that the present invention is described by way of some embodiments, and it will be appreciated by those skilled in the art that various changes or equivalent substitutions may be made to these features and embodiments without departing from the spirit and scope of the present invention. In addition, under the teachings of the present invention, these features and embodiments may be modified to adapt to specific circumstances and materials without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are intended to be protected by the present invention.

Claims

1. A method for automatically tensioning a scraper chain of a roadheader transport mechanism, characterized in that: The following steps are involved: Step 1: Start the tunnel boring machine and start adjustment; Step 2: Use the machine body inclination sensor to monitor the actual inclination angle α1 of the machine body in real time. When α1 is within the range of [-X, X], start tightening the conveyor chain directly. The specific steps are as follows: Check whether the proximity switch detects the conveyor chain. If not, the adjustment is complete. If the conveyor chain is detected, check the value of the tensioning stroke sensor. If the tensioning cylinder has not reached its maximum stroke, it will gradually extend at a certain step distance H0 until the conveyor chain leaves the detection range of the proximity switch. At this time, the conveyor chain is tensioned to the appropriate tightness and the tensioning is complete. Otherwise, when the tensioning cylinder is detected to be extended to the maximum, the tensioning reaches the maximum stroke and the tensioning is complete. Check whether the conveyor adjustment cylinder is at the initial length Lt by adjusting the cylinder stroke sensor. If not, adjust the conveyor adjustment cylinder to the initial length. Step 3: When it is detected that α1 is within the range of [-Y, -X) or (X, Y], the inclination angle of the machine body is adjusted by adjusting the rear support cylinder or the loading cylinder. When α1 reaches a certain range, the conveyor chain is tightened. The specific steps are as follows: Step 3.1: When α1 is detected to be within the range of [-Y, -X), the rear support cylinder is retracted to its shortest position, and the loading cylinder is gradually extended at a certain step distance L2 until α1 is detected to be within the range of [-X, X]. At this time, the machine body inclination adjustment is completed, and the conveyor chain is tensioned according to step 2; Step 3.2: When α1 is detected to be within the range of [X, Y], the loading cylinder is shortened to its shortest position, and the rear support cylinder is gradually extended at a certain step distance L1 until α1 is detected to be within the range of [-X, X]. At this time, the machine body inclination adjustment is completed, and the conveyor chain is tensioned according to step 2; Step 4: Use the conveyor inclination sensor to monitor the actual inclination angle α2 of the transport mechanism in real time. When it is detected that α1 is within the range of [-K, -Y) or (Y, K], the inclination angle of the machine body is adjusted by adjusting the rear support cylinder and the loading cylinder. Then, the inclination angle of the transport mechanism is adjusted by adjusting the conveyor adjustment cylinder. When the inclination angle of the transport mechanism reaches a certain range, the conveyor chain is tightened. The specific steps are as follows: Step 4.1: When α1 is detected to be within the range of [-K, -Y), the loading cylinder is extended to its maximum and the rear support cylinder is retracted to its minimum. At this time, it is checked whether α1 is within the range of [-X, X]. If so, the adjustment is completed. If not, the conveyor adjustment cylinder is gradually shortened by a certain step length L0 until α2 is detected to be within the range of [-β1-c, β1+c], where β1 is the absolute value of the initial inclination angle of the conveyor mechanism and c is a certain tolerance value. At this time, the conveyor mechanism inclination adjustment is completed and the conveyor chain is tensioned according to step 2. Step 4.2: When α1 is detected to be within the range of [Y, K], the rear support cylinder is extended to its maximum and the loading cylinder is retracted to its minimum. At this time, it is checked whether α1 is within the range of [-X, X]. If so, the adjustment is completed. If not, the conveyor adjustment cylinder is gradually extended at a certain step length L0 until α2 is detected to be within the range of [-β1-c, β1+c]. At this time, the conveyor mechanism inclination adjustment is completed and the conveyor chain is tensioned according to step 2. In the above, X is the maximum inclination angle of the machine body allowed when the scraper chain tensioning can be started without adjusting the machine body, that is, without adjusting the loading cylinder and the rear support cylinder; Y is the maximum inclination angle of the machine body allowed when the scraper chain tensioning can be started when the machine body adjustment is required but the conveyor adjustment cylinder does not need to be adjusted; K is the maximum inclination angle of the machine body that can be achieved after adjusting the angle of the transport mechanism via the conveyor adjustment cylinder. All three are positive values.

2. The automatic tensioning method for the scraper chain of the roadheader transport mechanism according to claim 1, characterized in that: The method includes step 5: when it is detected that α1<-K or α1>K, the adjustment range is exceeded and the adjustment is ended.

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