Self-adapting limit oil cylinder with pressure feedback for coal roadway support

Abstract

The present application belongs to the technical field of coal roadway support, and particularly relates to a coal roadway support self-adaptive limiting oil cylinder with pressure feedback; the oil cylinder comprises a hydraulic oil tank, an overflow valve, a constant flow oil source, an oil inlet filter, a three-position six-way directional control valve, a hydraulic control check valve, a shuttle valve, a lock cylinder valve, a support oil cylinder and accessories such as counterweight; when the support oil cylinder performs coal roadway roof support operation, the hydraulic oil flow into the rodless cavity of the support oil cylinder is automatically controlled according to the pressure feedback system composed of the hydraulic control check valve and the shuttle valve, so that the automatic limiting is realized when the cylinder rod of the support oil cylinder contacts the coal roof and reaches the set pre-tightening force, and the support oil cylinder or the coal roadway roof is prevented from being damaged. The present application has simple control logic, can reduce the labor intensity of workers, reduce the energy consumption of the hydraulic system, and improve the support operation efficiency of the support oil cylinder on the coal roadway roof.

Description

Technical Field

[0001] This invention belongs to the field of coal roadway support technology, specifically relating to an adaptive limit cylinder for coal roadway support with pressure feedback. Background Technology

[0002] Hydraulic cylinders, characterized by their high flexibility, strong impact load resistance, and ease of operation, are widely used in temporary support of coal mine roadways. Currently, temporary support cylinders for coal mine roadways are broadly classified into portable and stand-alone types: portable cylinders are controlled by a control valve assembly, and the operator manually checks whether the cylinder supports the roof during operation based on site conditions; stand-alone cylinders are transported to a designated location by support personnel who then manually pressurize the cylinder until the cylinder rod supports the coal roadway roof. In short, current support cylinder control is largely manual, resulting in low operational efficiency, high labor intensity, and the inability to determine whether the cylinder rod is properly positioned during temporary support operations in coal mine roadways. Summary of the Invention

[0003] This invention aims to solve the problem that existing support cylinders cannot determine whether the cylinder rod is properly supported during temporary support operations in coal mine coal-rock roadways.

[0004] This invention provides the following technical solution: a coal roadway support adaptive limit cylinder with pressure feedback, including a support cylinder; a pressure feedback system composed of a hydraulically controlled check valve and a shuttle valve is connected to the hydraulic system for controlling the support cylinder; the hydraulic system includes a directional valve and a hydraulic oil tank;

[0005] The inlet of the hydraulic check valve is connected to the control port of the rodless chamber of the support cylinder, the outlet of the hydraulic check valve is connected to the hydraulic oil tank, the control port of the hydraulic check valve is connected to the outlet of the shuttle valve, and the A and B inlets of the shuttle valve are connected to the rodless chamber of the support cylinder respectively.

[0006] The pressure of the rodless chamber port of N support cylinders is compared through the working port of the shuttle valve. The highest pressure of the rodless chamber of the support cylinder is used as a feedback signal. This signal is then sent to the control port of the hydraulic check valve through the outlet of the shuttle valve. This opens the hydraulic check valve, allowing the hydraulic oil in the control port of the directional valve to return directly to the hydraulic tank. This cuts off the hydraulic system's oil supply to the support cylinders, thereby stopping the extension operation of the support cylinders.

[0007] Furthermore, a cylinder lock valve is installed between the support cylinder and the directional valve. The oil inlet of the cylinder lock valve is connected to the control port of the rodless chamber of the support cylinder connected to the directional valve, and the oil outlet of the cylinder lock valve is connected to the rodless chamber of the support cylinder. This is used to protect the working state of the support cylinder and prevent malfunction. The control port of the cylinder lock valve is connected to the control port of the rod chamber of the support cylinder connected to the directional valve.

[0008] The cylinder locking valve ensures that the support cylinder can remain in a fixed extended state when there is no action signal. When the roof of the coal roadway is deformed by impact pressure, the cylinder locking valve can buffer the support cylinder and prevent it from being damaged by overload pressure. The buffering effect ensures that the support cylinder lever can achieve a certain amount of contraction when the pressure in the rodless chamber of the support cylinder does not change.

[0009] Furthermore, the hydraulic system also includes a relief valve. The inlet of the relief valve is connected to the inlet of the directional valve, and the outlet of the relief valve is directly connected back to the hydraulic oil tank to prevent the system pressure from increasing and damaging the hydraulic system.

[0010] Furthermore, the hydraulic system also includes an inlet filter for cleaning and filtering the oil supplied to the hydraulic system.

[0011] Furthermore, the directional control valve is a three-position six-way directional control valve. The T port of the three-position six-way directional control valve is connected to the hydraulic oil tank. The A port of the three-position six-way directional control valve is connected to the oil inlet of the cylinder lock valve. The B port of the three-position six-way directional control valve is connected to the rod chamber oil port of the support cylinder and the control oil port of the cylinder lock valve. The rodless chamber oil port of the support cylinder is connected to the oil outlet of the cylinder lock valve. The P port of the three-position six-way directional control valve is connected to the oil outlet of the inlet filter. The oil inlet of the hydraulic control check valve is connected to the A port of the three-position six-way directional control valve.

[0012] Compared with the prior art, the advantages of the present invention are:

[0013] 1. The hydraulic cylinder has sensitive adaptive feedback. Since this invention is designed for hydraulic cylinders used in coal mine roof support operations, which have strict requirements for roof pre-tightening pressure during operation, the feedback pressure of this invention is directly provided by the rodless chamber of the hydraulic cylinder, avoiding the influence of the cylinder lock valve on the feedback pressure.

[0014] 2. High feasibility: The solution provided by this invention only requires setting a pressure feedback system between the outside of the cylinder and the cylinder lock valve. When upgrading the original design, there is no need to replace the cylinder, which reduces the user's operating costs.

[0015] 3. Reduce system energy consumption. This invention combines the pressure feedback system composed of shuttle valve with the oil supply circuit through a hydraulic control check valve. When the pressure in the rodless chamber of the oil cylinder reaches a predetermined value, the pressure oil is unloaded to reduce the work done by the overflow of system pressure oil.

[0016] 4. Reduce system heat generation: Since this invention reduces system energy consumption, it can reduce system heat generation to a certain extent. Attached Figure Description

[0017] Figure 1 This is a structural diagram of an adaptive limit cylinder for coal roadway support with pressure feedback.

[0018] Figure 2Simulation diagram of hydraulic cylinder pressure-stroke parameters when all cylinder rods are in contact with the roof of the coal roadway and subjected to a 300KN pressure impact;

[0019] Figure 3 Simulation diagram of pressure parameters before and after the cylinder lock valve when the hydraulic cylinder is under load.

[0020] In the diagram: 1-Hydraulic oil tank; 2-Relief valve; 3-Constant flow oil source; 4-Inlet filter; 5-Three-position six-way directional control valve; 6-Hydraulic check valve; 7-Shuttle valve; 8-Cylinder lock valve; 9-Support cylinder; 10-Counterweight and other accessories. Detailed Implementation

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Combination Figure 1 This embodiment of a coal roadway support adaptive limit cylinder with pressure feedback includes a hydraulic oil tank 1, an overflow valve 2, a constant flow oil source 3, an oil inlet filter 4, a three-position six-way directional control valve 5, a hydraulic control check valve 6, a shuttle valve 7, a cylinder lock valve 8, a support cylinder 9, and accessories such as counterweights 10.

[0023] The inlet of relief valve 2 is connected to the outlet of inlet filter 4, and the outlet of relief valve 2 is directly connected back to hydraulic oil tank 1 to prevent the hydraulic system from being damaged by increased system pressure. Constant flow oil source 3 is directly connected to the inlet of inlet filter 4 to supply oil to the hydraulic system. The outlet of inlet filter 4 is connected to the P port of three-position six-way directional control valve 5 to clean and filter the oil supplied to the hydraulic system by constant flow oil source 3. The T port of three-position six-way directional control valve 5 is connected to hydraulic oil tank 1, the A port of three-position six-way directional control valve 5 is connected to the inlet of cylinder lock valve 8, and the B port of three-position six-way directional control valve 5 is connected to the rod chamber port of support cylinder 9 and the cylinder lock valve 8, respectively. The control port is connected to change the working state of the support cylinder 9; the hydraulic control check valve 6 and the shuttle valve 7 together constitute a pressure feedback system, wherein the oil inlet of the hydraulic control check valve 6 is connected to port A of the three-position six-way directional control valve 5, the oil outlet of the hydraulic control check valve 6 is connected to the hydraulic oil tank 1, the control port of the hydraulic control check valve 6 is connected to the oil outlet of the shuttle valve 7, and the A and B oil inlets of the shuttle valve 7 are respectively connected to the rodless chamber oil port of the support cylinder 9; the rodless chamber oil port of the support cylinder 9 is connected to the oil outlet of the cylinder lock valve 8 to protect the working state of the support cylinder and prevent malfunction; the rod chamber oil port of the support cylinder 9 is connected to port B of the three-position six-way directional control valve 5 for the roof support operation in the coal roadway.

[0024] It can consist of N support cylinders connected in parallel. In actual operation, the cylinder rod of any support cylinder can extend arbitrarily within its stroke range. When the cylinder rods of N support cylinders contact the coal roof and reach the set preload, they automatically stop to prevent damage to the support cylinders or the coal roadway roof.

[0025] The entire system works as follows:

[0026] When the cylinder rod extends: the three-position six-way directional control valve 5 is in the left position, and the constant flow oil source 3 enters the rodless chamber of the support cylinder 9 through port A of the three-position six-way directional control valve 5 and the cylinder lock valve 8, causing the cylinder rod of the support cylinder to extend until the cylinder rod contacts the roof of the coal roadway and the rated preload is produced. As the pressure in the rodless chamber of the support cylinder 9 increases, the hydraulic control check valve 6 is opened through the shuttle valve 7, so that the constant flow oil source 3 returns to the hydraulic oil tank 1 through the hydraulic control check valve 6, realizing the self-adaptive limit of the support cylinder 9.

[0027] When the cylinder lever retracts: the three-position six-way directional control valve 5 is in the right position, and the constant flow oil source 3 enters the rod chamber of the support cylinder 9 through port B of the three-position six-way directional control valve 5. As the pressure in the rod chamber of the support cylinder increases, the cylinder lock valve 8 is opened, and the hydraulic oil in the rod chamber of the support cylinder 9 returns to the hydraulic oil tank 1 through port A of the three-position six-way directional control valve 5.

[0028] When the hydraulic cylinder lever stops extending: the three-position six-way directional control valve 5 is in the neutral position, the constant flow oil source 3 returns directly to the hydraulic oil tank 1, and the cylinder rod of the support cylinder 9 stops extending under the action of the cylinder lock valve 8.

[0029] The significant advantages of this invention compared to existing technologies are:

[0030] This invention uses pressure feedback control limit to replace the traditional mechanical control limit, making the support cylinder system more flexible and improving operating efficiency.

[0031] This invention offers a wider selection of system oil sources, which is beneficial for the system to be used in more scenarios with different requirements.

[0032] This invention incorporates a pressure feedback system on the actuator's hydraulic cylinder, facilitating equipment upgrades and maintenance.

[0033] To further verify the feasibility of the system, the system execution parameters were set as follows: two hydraulic cylinders, each with a piston diameter of 150 mm, a lever rod diameter of 120 mm, a limit length of 0.6 m for the left cylinder, a limit length of 0.4 m for the right cylinder, a pre-warning pressure of 40 kN after jacking, a working pressure of 28 MPa for the cylinder lock valve, an opening pressure of 7 MPa for the hydraulic check valve, and an opening pressure of 16 MPa for the protection valve. A simulation study of the system was conducted, and the results are as follows: Figure 2 , Figure 3 As shown.

[0034] As can be seen from the above, this invention incorporates a pressure feedback system into the support cylinder system, achieving automatic control of the support cylinder's operating state by comparing the pressure in the rodless chamber of the support cylinder system. This invention is beneficial for improving the efficiency of temporary support operations in coal mine roadways.

[0035] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A coal roadway support adaptive limit cylinder with pressure feedback, comprising a support cylinder (9); characterized in that: The hydraulic system used to control the support cylinder (9) is connected to a pressure feedback system consisting of a hydraulically controlled check valve (6) and a shuttle valve (7); the hydraulic system includes a directional valve and a hydraulic oil tank (1). The inlet of the hydraulic check valve (6) is connected to the control port of the rodless chamber of the support cylinder (9) of the directional valve. The outlet of the hydraulic check valve (6) is connected to the hydraulic oil tank (1). The control port of the hydraulic check valve (6) is connected to the outlet of the shuttle valve (7). The A and B inlets of the shuttle valve (7) are connected to the rodless chamber of the support cylinder (9) respectively. The pressure of the rodless chamber of the N support cylinders (9) is compared with the pressure of the working port of the shuttle valve (7). The highest pressure of the rodless chamber of the support cylinder (9) is used as a feedback signal. The pressure is applied to the control port of the hydraulic check valve (6) through the outlet of the shuttle valve (7), thereby opening the hydraulic check valve (6) and allowing the hydraulic oil in the control port of the directional valve to return directly to the hydraulic oil tank (1), thereby cutting off the oil supply from the hydraulic system to the support cylinders (9) and thus stopping the extension operation of the support cylinders (9). A cylinder lock valve (8) is provided between the support cylinder (9) and the reversing valve. The oil inlet of the cylinder lock valve (8) is connected to the control port of the rodless chamber of the support cylinder (9) connected to the reversing valve. The oil outlet of the cylinder lock valve (8) is connected to the rodless chamber of the support cylinder (9). It is used to protect the working state of the support cylinder (9) and prevent malfunction. The control port of the cylinder lock valve (8) is connected to the control port of the rod chamber of the support cylinder (9) connected to the reversing valve.

2. The adaptive limit cylinder for coal roadway support with pressure feedback according to claim 1, characterized in that: The hydraulic system also includes a relief valve (2), the oil inlet of which is connected to the oil inlet of the directional valve, and the oil outlet of the relief valve (2) is directly connected back to the hydraulic oil tank (1) to prevent the system pressure from increasing and damaging the hydraulic system.

3. The adaptive limit cylinder for coal roadway support with pressure feedback according to claim 2, characterized in that: The hydraulic system also includes an inlet filter (4) for cleaning and filtering the oil supplied to the hydraulic system.

4. The adaptive limit cylinder for coal roadway support with pressure feedback according to claim 2, characterized in that: The directional control valve is a three-position six-way directional control valve (5). The T port of the three-position six-way directional control valve (5) is connected to the hydraulic oil tank (1). The A port of the three-position six-way directional control valve (5) is connected to the oil inlet of the cylinder lock valve (8). The B port of the three-position six-way directional control valve (5) is connected to the rod chamber oil port of the support cylinder (9) and the control oil port of the cylinder lock valve (8). The rodless chamber oil port of the support cylinder (9) is connected to the oil outlet of the cylinder lock valve (8). The P port of the three-position six-way directional control valve (5) is connected to the oil outlet of the inlet filter (4). The oil inlet of the hydraulic check valve (6) is connected to the A port of the three-position six-way directional control valve (5).

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