Vibration-damping long tensioning device for mining machine and three-section tensioning structure of mining machine fuselage

Abstract

The present invention relates to a vibration damping type long tensioning device for a mining machine and a three-section tensioning structure of the mining machine body. In the long tensioning device, the first and second long screws are coaxially fixedly connected through a threaded sleeve. One end of a shock absorber is fixed on the threaded sleeve, and the other end is a free end. The main vibration damping direction of the shock absorber is along the radial direction of the threaded sleeve. The three-section tensioning structure of the machine body includes a left traction part, an intermediate electric control box, and a right traction part that are arranged adjacent to each other in sequence from left to right to form the machine body. An installation groove with a downward notch and extending left and right is provided on the machine body. The left and right groove walls of the installation groove are respectively served by the left and right traction parts. In the installation state, the first and second long screws respectively penetrate through the left and right through holes on the left and right groove walls and are fastened to the machine body through hydraulic nuts and round nuts. The free end of the shock absorber is fixedly connected relative to the machine body. The long tensioning device of the present invention will not have early fatigue failure, which is beneficial to reducing the number of inspections and maintenance, lowering the use cost, and improving the connection reliability of the mining machine body.

Description

Technical Field

[0001] The present invention relates to a long tensioning device and a three-section tensioning structure of a mining machine body composed of the long tensioning device. The long tensioning device is mainly used on the body of the mining machine to realize the connection between several split parts. Background Art

[0002] Generally, a mining machine for underground coal mining has 4 to 6 groups of long tensioning devices distributed around the body. The main function is to connect and tension the three sections of the mining machine body (left traction part, middle electric control box, right traction part) to prevent the three sections of the body from loosening due to the cutting reaction force during the operation of the mining machine, resulting in safety accidents. Currently, each group of existing long tensioning devices includes a long screw rod with a length of 4 m to 6 m. Both ends of the long screw rod are threaded sections and are tensioned by means of hydraulic nuts, etc. Almost all of the middle part of the long screw rod is suspended.

[0003] When the mining machine mines ore in the fully mechanized coal face, the cutting reaction force borne by the cutting drum of the mining machine is transmitted to the body of the mining machine. Due to the change of the geological conditions of the ore seam, the cutting reaction force often shows an impact load, which is an impact vibration source for the body. At the same time, when the mining machine travels on the scraper conveyor pin row, it will also form a vibration source. The superposition of various vibration sources causes the long tensioning devices connecting the three sections of the mining machine body to have high-frequency vibrations and sometimes resonance. The amplitude is the largest at the middle part of the long screw rod, resulting in fatigue fracture of the long screw rod in the initial stage of use and failing to reach the design life of the long tensioning device. In order to avoid secondary failures and safety accidents, it is necessary to immediately repair and replace the entire long screw rod, increasing the usage cost of the mine. Summary of the Invention

[0004] The present invention aims to provide a vibration-damping long tensioning device for a mining machine and a three-section tensioning structure of a mining machine body. The long tensioning device will not have early fatigue failure, so it is beneficial to reduce the number of inspections and maintenance, reduce the usage cost, and improve the reliability of the three-section tensioning structure of the mining machine body.

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

[0006] A vibration damping type long tensioning device for a mining machine, comprising a first long screw rod, a second long screw rod, a threaded sleeve and a shock absorber, and may or may not include a transition long screw rod. One end of the first long screw rod and one end of the second long screw rod are respectively threadedly connected coaxially into the threaded sleeve from both ends of the threaded sleeve. Or, one end of the first long screw rod and one end of a transition long screw rod are respectively threadedly connected coaxially into the threaded sleeve from both ends of the threaded sleeve. At the same time, one end of the second long screw rod and the other end of the transition long screw rod are respectively threadedly connected coaxially into the corresponding threaded sleeve from both ends of another threaded sleeve. Each of the threaded sleeves is provided with the shock absorber outside. One end of the shock absorber is fixedly installed on the corresponding threaded sleeve, and the other end is a free end. The designed main shock damping direction of the shock absorber is along the radial direction of the threaded sleeve.

[0007] The other end of the first long screw rod is threadedly connected with a hydraulic nut, and inside the hydraulic nut on the first long screw rod is a first washer. The other end of the second long screw rod is threadedly connected with a round nut, and inside the round nut on the second long screw rod is a second washer.

[0008] The outer shape of the round nut is a cylindrical barrel shape. A plurality of blind holes are arranged at intervals along the circumferential direction on the outer cylindrical surface of the round nut, and the center lines of the blind holes are vertically directed towards the axis of the round nut.

[0009] A plurality of the shock absorbers are installed on the outer periphery of a single threaded sleeve, and the plurality of shock absorbers are arranged dispersedly along the circumferential direction.

[0010] At least two pairs of planes are arranged along the circumferential direction on the outer surface of the threaded sleeve. The two planes in a pair are parallel to the center line of the threaded sleeve and are symmetrically arranged relative to the center line of the threaded sleeve. Different pairs of planes are not parallel to each other.

[0011] Two of the shock absorbers are provided on the outer periphery of each threaded sleeve, and the two shock absorbers are separately installed on the two planes in a pair.

[0012] Preferably, the shock absorber includes a plurality of springs connected in parallel. One end of each spring is fixedly connected to the same connecting plate, and the other end of each spring is fixedly connected to another connecting plate. One of the connecting plates constitutes the free end of the shock absorber.

[0013] Among the springs of the shock absorber, the springs at both sides are long-stroke springs with a larger stiffness, and the springs in the middle are short-stroke springs with a smaller stiffness, and the spring stiffnesses at both sides are equal.

[0014] A three-section tensioning structure for a mining machine body, comprising a mining machine body and a vibration-damping long tensioning device for the mining machine. The mining machine body includes a left traction part, an intermediate electric control box, and a right traction part arranged adjacent to each other from left to right. A long tensioning device installation groove with a downward notch is provided at the lower part of the body. The left and right groove walls of the long tensioning device installation groove are respectively formed by a part of the shells of the left traction part and the right traction part. A left through hole and a right through hole are respectively provided on the left and right groove walls. In the installed state, most of the vibration-damping long tensioning device for the mining machine is located in the long tensioning device installation groove. The other ends of the first long screw and the second long screw respectively penetrate through the left through hole and the right through hole. One of the hydraulic nut and the round nut is located on the left side of the left groove wall, and the other is located on the right side of the right groove wall. The free end of the shock absorber is fixedly connected to the mining machine body.

[0015] In the vibration-damping long tensioning device for the mining machine, two shock absorbers, one above the other, are installed on each threaded sleeve. A bottom plate is fixed at the notch of the long tensioning device installation groove. The free end of the shock absorber located above is connected to the bottom surface of the long tensioning device installation groove, and the free end of the shock absorber located below is connected to the bottom plate.

[0016] The beneficial effects of the present invention are as follows:

[0017] The present invention uses a multi-section split screw combination to replace the existing single whole long screw with a length of 4 - 6 meters, and shock absorbers are provided at the joints of different section split screws. This not only changes the natural frequency of the long tensioning device to avoid resonance with the mining machine, but also significantly reduces the vibration amplitude in the middle of the long tensioning device by using the shock absorbers, solves the problem of early fatigue fracture of the long screw in the existing long tensioning device due to high-frequency vibration and excessive amplitude, and improves the reliability of the long tensioning device.

[0018] By changing the lengths of some or all of the split screws in the multi-section split screw combination, the natural frequency of the obtained long tensioning device can be conveniently changed, making the design of the long tensioning device more flexible and facilitating adaptation to mining machines of different models.

[0019] When a certain section of the threaded section of a long screw breaks, rusts, or other failures occur and it cannot be used, only the failed section of the long screw needs to be replaced, avoiding the entire scrapping of the whole long screw, which is beneficial for the mining party to reduce spare parts inventory, improves the adaptability and maintenance convenience of the long tensioning device, reduces the use cost, and also improves the connection reliability of the three-section tensioning structure of the mining machine body.

[0020] Preferably, the springs of the shock absorber adopt long-stroke springs with a relatively large stiffness on both sides and short-stroke springs with a relatively small stiffness in the middle, and the spring stiffness on both sides is equal. When the multi-section split screw combination vibrates, the springs in the shock absorber act simultaneously; when encountering an extreme situation where the vibration is instantaneously excessive, the short-stroke springs in the middle can immediately play a major role, quickly limiting the amplitude to an acceptable level, and reducing or even eliminating the impact of shock vibration as quickly as possible, thereby significantly improving the safety and reliability of the three-section tension of the mining machine body. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a schematic diagram of the principle of the first embodiment of the present invention;

[0022] Figure 2 is a schematic structural diagram of the second embodiment of the present invention;

[0023] Figure 3 is a schematic end face diagram of the thread sleeve;

[0024] Figure 4 is Figure 3 the A-A sectional view of

[0025] Figure 5 is a schematic structural diagram of an embodiment of the shock absorber;

[0026] Figure 6 is a schematic structural diagram of an embodiment of the three-section tension structure of the mining machine body;

[0027] Figure 7 is a schematic structural diagram of another embodiment of the three-section tension structure of the mining machine body.

[0028] Reference Signs:

[0029] 1. Hydraulic nut; 2. First long screw; 3. Shock absorber; 3-1. Spring; 3-2. Connecting plate; 3-3. Screw; 4. Transition long screw; 5. Thread sleeve; 5-1. Plane; 6. Second long screw; 7. Washer; 8. Round nut; 9. Left traction part; 10. Electric control box; 11. Right traction part; 12. Bottom plate. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0030] The present invention discloses a vibration damping type long tensioning device for a mining machine (which can be abbreviated as a long tensioning device), as Figures 1-5As shown in the figure, it includes a first long screw rod 2, a second long screw rod 6, a threaded sleeve 5 and a shock absorber 3, and may or may not include a transition long screw rod 4. The first long screw rod and the second long screw rod can be coaxially connected through a threaded sleeve, or the first long screw rod, the transition long screw rod and the second long screw rod can be coaxially connected in sequence through two threaded sleeves. The shock absorber is installed outside each of the threaded sleeves. One end of the shock absorber is detachably fixed on the corresponding threaded sleeve, and the other end is a free end. The designed main shock absorption direction of the shock absorber (i.e., the direction with the largest elastic deformation theoretically) is along the radial direction of the threaded sleeve.

[0031] The first long screw rod, the transition screw rod and the second long screw rod are all double-headed screw rods, and the non-threaded part in the middle of the screw rod is a cylinder with a diameter smaller than the thread diameters at both ends.

[0032] The present invention uses a multi-segment split screw rod combination with a coaxial arrangement of a first long screw rod 2, a second long screw rod 6 and with or without a transition long screw rod 4 to replace the existing 4-6-meter-long integral screw rod. A shock absorber is provided at the connection of different segments of the split screw rods. While being used for tensioning and fixing, since the natural frequency of the long tensioning device itself is changed, resonance with the mining machine can be avoided, and the vibration amplitude in the middle of the long tensioning device is significantly reduced by using the shock absorber. Therefore, the problem that the long tensioning device is prone to early fatigue fracture due to high-frequency vibration and excessive amplitude during the working process of the mining machine is solved.

[0033] The lengths of the first long screw rod 2, the transition long screw rod 4 and the second long screw rod 6 are usually different from each other (in a few cases, there may also be equal lengths or two of them being equal), and are specifically determined by the designed natural frequency of the long tensioning device. By changing the lengths of some or all of the split screw rods in the multi-segment split screw rod combination, the natural frequency of the obtained long tensioning device after combination can be conveniently changed, so that it can conveniently adapt to mining machines of different models.

[0034] The other end of the first long screw rod is threadedly connected with a hydraulic nut 1, and a washer 7 is arranged inside the hydraulic nut on the first long screw rod. The other end of the second long screw rod is threadedly connected with a round nut 8, and a washer 7 is arranged inside the round nut on the second long screw rod. For the sake of distinction, the washers on the first long screw rod and the second long screw rod are respectively called the first washer and the second washer.

[0035] The outer shape of the round nut is a cylindrical barrel shape, and a plurality of blind holes are arranged at intervals along the circumferential direction on the outer cylindrical surface of the round nut. The center lines of the blind holes are perpendicular to the axis of the round nut. The blind holes can be used to insert rod-shaped tools to facilitate the rotation of the round nut for disassembly and assembly. The round nut has a smaller outer diameter size compared with a hexagonal nut and is convenient for rotary assembly. In this embodiment, 8 such blind holes are evenly distributed in the circumferential direction on the round nut.

[0036] A plurality of the shock absorbers can be installed on the outer periphery of a single one of the threaded sleeves, and the plurality of shock absorbers are arranged dispersedly in the circumferential direction, and are further preferably evenly distributed along the outer periphery of the threaded sleeve. In this embodiment, two shock absorbers are fixedly installed outside each threaded sleeve, and are spaced 180 degrees in the circumferential direction.

[0037] At least two pairs of planes 5-1 are arranged on the outer surface of the threaded sleeve in the circumferential direction. The two planes in a pair are parallel to the central axis of the threaded sleeve and are symmetrically arranged relative to the central axis of the threaded sleeve, and the different pairs of planes are not parallel to each other. The arrangement of multiple pairs of planes can facilitate the rotational installation and disassembly of the threaded sleeve. At least one pair of planes can be used for the installation of the shock absorbers. In this embodiment, two shock absorbers are arranged on the outer periphery of each threaded sleeve, and the two shock absorbers are separately installed on two parallel planes in a pair.

[0038] As Figure 5 shown, the shock absorber can include a plurality of springs 3-1 connected in parallel. One end of each spring is fixedly connected to the same connecting plate 3-2, and the other end of each spring is fixedly connected to another connecting plate 3-2. One of the connecting plates constitutes the free end of the shock absorber. When the shock absorber is installed, one connecting plate can be fixed to the threaded sleeve by screws 3-3, and the other connecting plate can be fixed to the mining machine body.

[0039] Among the springs of the shock absorber, it is preferable that longer-travel springs with a larger stiffness are used on both sides, and shorter-travel springs with a smaller stiffness are used in the middle, and the spring stiffness on both sides is equal. When the multi-section split screw vibrates, the springs in the shock absorber act simultaneously; when encountering an extreme situation where the vibration is instantaneously too large, the short-travel springs in the middle can immediately play a major role, can quickly limit the amplitude to an acceptable level, and can reduce or even eliminate the influence of the impact vibration as quickly as possible, significantly improving the safety and reliability of the three-section tensioning of the mining machine body. In the embodiment shown in the drawings, the shock absorber has three springs.

[0040] The present invention also discloses a three-section tensioning structure of a mining machine body, as Figure 6 and Figure 7As shown in the figure, it includes the mining machine body and the vibration-damping long tensioning device for the mining machine. The mining machine body includes a left traction part 9, an intermediate electric control box 10, and a right traction part 11 that are arranged adjacent to each other from left to right. A long tensioning device installation groove with a downward notch and extending left and right is provided at the lower part of the body. The left groove wall and the right groove wall of the long tensioning device installation groove are respectively formed by a part of the shells of the left traction part and the right traction part. A left through hole and a right through hole are respectively provided on the left groove wall and the right groove wall. In the installed state, most of the vibration-damping long tensioning device for the mining machine is located in the long tensioning device installation groove. The other ends of the first long screw and the second long screw respectively penetrate through the left through hole and the right through hole. One of the hydraulic nut and the round nut is located on the left side of the left groove wall, and the other is located on the right side of the right groove wall. The free end of the shock absorber is fixedly connected relative to the mining machine body.

[0041] A sunken groove can also be provided on the left side surface of the left groove wall and the right side surface of the right groove wall. The washers on the first long screw and the second long screw are respectively installed in the two sunken grooves.

[0042] In the embodiment shown in the attached drawing, two shock absorbers, one above the other, are installed on each threaded sleeve and are arranged on a pair of parallel planes on the threaded sleeve. The main shock-absorbing direction of the shock absorber is the up and down direction. A bottom plate 12 is fixedly installed outside the notch of the long tensioning device installation groove. The free end of the upper shock absorber is connected to the bottom surface of the long tensioning device installation groove (i.e., the intermediate electric control box) through the connecting plate on it. The free end of the lower shock absorber is connected to the bottom plate through the connecting plate on it. The size of the bottom plate is not limited. It can enclose the entire notch of the long tensioning device installation groove or only cover a part of the notch. In the embodiment shown in the attached drawing, the latter is adopted.

[0043] The cross-sections of the left through hole and the right through hole are in an inverted U shape. During installation, first connect multiple split screws in combination, and then install the first long screw and the second long screw into the left and right through holes from bottom to top. At this time, most of the combined multiple split screws are located in the long tensioning device installation groove. Then install the upper shock absorber 3, and fix the shock absorber between the threaded sleeve and the long tensioning device installation groove through the screw 3-3. Then, use a super high-pressure manual pump to pressurize and tighten the hydraulic nut 1. Finally, install the lower shock absorber and the bottom plate. Before installing the above-mentioned combined multiple split screws into the long tensioning device installation groove, one end of the shock absorber can also be connected to the threaded sleeve first.

[0044] Usually, multiple sets of long tensioning devices are installed at intervals at one part of the mining machine body at the same time. These long tensioning devices are parallel to each other and usually share the same long tensioning device installation groove.

[0045] Whether to install the transition long screw can be selected according to the vibration mode of the mining machine. For example, when the mining machine is working, if the vibration mode is the first-order vibration mode, it is recommended to adopt the combination of the first long screw and the second long screw. If the vibration mode is the second-order vibration mode, it is preferably to adopt the combination of the first long screw, the transition long screw and the second long screw.

[0046] The installation method of the multi-segment split screw combination is as follows: First, connect each section of the long screw coaxially through the threaded sleeve in turn. The other end of the second long screw is tightened with a round nut 8 and a washer 7. The other end of the first long screw is sleeved into the washer 7, and then screwed into the hydraulic nut 1 to form an assembly unit.

[0047] By changing the lengths of the split screws in each section, the total length and shape of the long tensioning device are changed, which also changes the mass, mass distribution and stiffness of the long tensioning device, thereby changing the natural frequency of the long tensioning device and avoiding resonance with the mining machine. Then, the shock absorber is used to damp the middle section or the large-amplitude section of the long tensioning device, further reducing the amplitude of the long tensioning device and avoiding the early fatigue fracture failure caused by high-frequency vibration. In addition, by connecting two sections of split screws through a threaded sleeve, when a certain section of the long screw has a fault such as fracture or rust in the threaded section and cannot be used, only the failed section of the long screw needs to be replaced, avoiding the entire long screw from being scrapped. Therefore, the use cost can be reduced, which is beneficial for the mining party to reduce the spare parts inventory and improve the maintenance convenience of the mining machine.

Claims

1. A vibration damping type long tensioning device for a mining machine, Characterized in that: It includes a first long screw, a second long screw, a threaded sleeve and a shock absorber, and may or may not include a transition long screw. One end of the first long screw and one end of the second long screw are respectively threadedly connected coaxially into the threaded sleeve from both ends of a threaded sleeve. Or, one end of the first long screw and one end of a transition long screw are respectively threadedly connected coaxially into the threaded sleeve from both ends of a threaded sleeve. At the same time, one end of the second long screw and the other end of the transition long screw are respectively threadedly connected coaxially into the corresponding threaded sleeve from both ends of another threaded sleeve. Each of the threaded sleeves is provided with the shock absorber outside. One end of the shock absorber is fixed on the corresponding threaded sleeve, and the other end is a free end. The designed main shock damping direction of the shock absorber is along the radial direction of the threaded sleeve. The shock absorber includes multiple parallel springs. One end of each spring is fixedly connected to the same connecting plate, and the other end of each spring is fixedly connected to another connecting plate. One of the connecting plates constitutes the free end of the shock absorber. Among the springs of the shock absorber, the springs at both sides are long-stroke springs with larger stiffness, and the middle is a short-stroke spring with smaller stiffness. The spring stiffness of the springs on both sides is equal.

2. The vibration damping type long tensioning device for a mining machine according to claim 1, Characterized in that: A hydraulic nut is threadedly connected to the other end of the first long screw, and a first washer is arranged inside the hydraulic nut on the first long screw; a round nut is threadedly connected to the other end of the second long screw, and a second washer is arranged inside the round nut on the second long screw.

3. The vibration damping type long tensioning device for a mining machine according to claim 2, Characterized in that: The outer shape of the round nut is a cylindrical barrel shape, and a plurality of blind holes are arranged at intervals along the circumferential direction on the outer cylindrical surface of the round nut. The center line of the blind hole is vertically directed towards the axis of the round nut.

4. The vibration damping type long tensioning device for a mining machine according to claim 2, Characterized in that: A plurality of the shock absorbers are installed on the outer circumference of a single threaded sleeve, and the plurality of shock absorbers are arranged dispersedly along the circumferential direction.

5. The vibration damping type long tensioning device for a mining machine according to claim 4, Characterized in that: At least two pairs of planes are arranged along the circumferential direction on the outer surface of the threaded sleeve. The two planes in a pair are parallel to the center line of the threaded sleeve and are symmetrically arranged relative to the center line of the threaded sleeve. Different pairs of planes are not parallel to each other.

6. The vibration damping type long tensioning device for a mining machine according to claim 5, Characterized in that: Two of the shock absorbers are arranged on the outer circumference of each threaded sleeve, and the two shock absorbers are separately installed on the two planes in a pair.

7. A three-section tensioning structure for the fuselage of a mining machine, Characterized in that: Comprising a mining machine body and the vibration-damping long tensioning device for a mining machine according to any one of claims 1-6, the mining machine body includes a left traction part, an intermediate electronic control box, and a right traction part which are arranged adjacent to each other from left to right. A long tensioning device installation groove with a downward notch is provided at the lower part of the body. The left groove wall and the right groove wall of the long tensioning device installation groove are respectively formed by a part of the shells of the left traction part and the right traction part. A left through hole and a right through hole are respectively provided on the left groove wall and the right groove wall. In the installed state, most of the vibration-damping long tensioning device for a mining machine is located in the long tensioning device installation groove. The other ends of the first long screw and the second long screw respectively penetrate through the left through hole and the right through hole. One of the hydraulic nut and the round nut is located on the left side of the left groove wall, and the other is located on the right side of the right groove wall. The free end of the shock absorber is fixedly connected to the mining machine body.

8. The vibration-damping long tensioning device for a mining machine according to claim 7, characterized in that: two shock absorbers, one above the other, are installed on each threaded sleeve of the vibration-damping long tensioning device for a mining machine. A bottom plate is fixed at the notch of the long tensioning device installation groove. The free end of the shock absorber located above is connected to the bottom surface of the long tensioning device installation groove, and the free end of the shock absorber located below is connected to the bottom plate.

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