Supporting device with buffer piston

Abstract

The invention relates to a supporting device with a buffer piston, which comprises a hydraulic cylinder (14), a force bearing piston (2) positioned in the hydraulic cylinder and a buffer piston (1) positioned in the force bearing piston (2), and a buffer device is arranged in the buffer piston. The lower portion of a hollow pressing rod (3) in the center of the buffering device penetrates through a buffering piston bottom hole (1-1) in the bottom of the buffering piston (1) to be supported at the bottom in the force bearing piston. A supporting piston pressure spring (12) is arranged in the bearing piston below the buffer piston, a buffer piston pressure spring (11) is arranged at the upper part of the buffer device in the buffer piston, and the upper part of the buffer piston pressure spring is supported on a buffer piston top surface (1-3) at the top of the buffer piston. Under the certain bearing condition, the impact load can be buffered, and the impact load action peak value is reduced. The supporting device effectively solves the problem of cylinder explosion caused by sudden increase of hydraulic pressure in the hydraulic cylinder when the hydraulic cylinder is impacted in the prior art.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of support protection equipment, in particular to a support device with a buffer piston. BACKGROUND

[0002] In the process of coal mining, especially deep coal mining, the roof of the working face will accumulate a lot of energy, and may suddenly release, forming strong rock burst. When the rock burst acts on the hydraulic support, it shows as an instantaneous and high-intensity impact load. Under this working condition, the pressure borne by the hydraulic cylinder of the stand column and its supporting piston will rise sharply, which easily leads to cylinder body burst due to overpressure, or plastic bending of the slender supporting piston, causing instability and even collapse of the support, which seriously threatens the safety production of the mine. To cope with this challenge, the most common solution in the prior art is to set a safety valve or overflow valve in the hydraulic control circuit of the hydraulic cylinder. The working principle is: when the pressure in the hydraulic cylinder exceeds the preset opening pressure of the valve, the valve core opens under the action of pressure to overcome the spring pre-tightening force, and the high-pressure liquid in the cylinder is relieved, so that the supporting piston is safely retracted, thereby reducing the pressure in the cylinder. However, this pressure valve-based pressure relief protection method has inherent and difficult-to-overcome defects: 1. Response lag: the opening of the valve requires the continuous action of hydraulic pressure to accumulate enough force to overcome the spring pre-tightening force, valve core inertia and static friction. This process takes a certain amount of time, causing the valve to not respond immediately at the moment of impact.

[0003] 2. Gradual opening: the opening of the valve is a gradual process, and its flow area gradually increases with the increase of pressure, which cannot provide the maximum flow capacity at the first time.

[0004] 3. Limited flow capacity: limited by the valve body structure and installation space, the rated flow of a single valve is limited, and when facing the instantaneous large flow of pressure relief demand, the pressure relief speed often cannot keep up with the pressure rise speed, forming a pressure relief bottleneck.

[0005] In summary, the lag-gradual response characteristics of the existing pressure valve make it relatively slow in response when facing the millisecond-level intense impact load in coal mining, and the pressure relief effect is very limited, which cannot provide timely and effective protection for the hydraulic support. SUMMARY

[0006] Technical problem: the present application provides a support device with a buffer piston, which significantly reduces the peak value of the impact load acting on the hydraulic support device by installing a buffer piston to produce a buffering effect on the impact load, effectively solving the anti-impact problem existing in the prior art.

[0007] Technical solution: The supporting device with a buffer piston comprises a hydraulic cylinder, a force-bearing piston in the hydraulic cylinder, a buffer piston in the force-bearing piston, a buffer device in the buffer piston, a hollow pressure rod in the center of the buffer device, the lower part of the hollow pressure rod passing through the buffer piston bottom hole in the bottom of the buffer piston and being supported on the bottom of the force-bearing piston, a support piston compression spring in the force-bearing piston below the buffer piston, and a buffer piston compression spring in the upper part of the buffer device in the buffer piston, the upper part of the buffer piston compression spring being supported on the buffer piston top surface in the top of the buffer piston.

[0008] The buffer piston is a cylindrical cavity with variable wall thickness, that is, the inner diameter of the upper half of the buffer piston is smaller than the inner diameter of the lower half, the inner diameter of the upper half and the inner diameter of the lower half are connected and transitioned by a wall thickness abrupt change conical platform, the center of the bottom of the buffer piston is provided with a buffer piston bottom hole, and the top of the buffer piston is provided with a buffer piston top surface.

[0009] The buffer device takes the pressure rod support platform as a basic piece, the hollow pressure rod is fixedly connected in the center of the pressure rod support platform, the release sleeve is arranged on the outer periphery of the hollow pressure rod above the pressure rod support platform, the inner positioning sleeve is arranged on the upper part of the release sleeve, and the outer positioning sleeve is arranged on the outer periphery of the inner positioning sleeve.

[0010] The hollow pressure rod is provided with a positioning rod, the hollow pressure rod is provided with a pressure rod hole, the upper end of the positioning rod is connected with a fixed clamping sleeve, the fixed clamping sleeve is provided with a positioning pin, the positioning pin passes through the pressure rod hole on the hollow pressure rod and is fixed with the inner positioning sleeve and the outer positioning sleeve respectively.

[0011] The upper part of the release sleeve is provided with an upper convex part, the middle part is provided with a middle concave part, the lower part is provided with a lower convex part, the middle concave part and the outer positioning sleeve are provided with a clamping spring, the middle concave part and the buffer piston are provided with a force-bearing clamping spring, and the clamping spring and the force-bearing clamping spring are provided with a gasket spring.

[0012] The clamping spring is an open C-shaped clamping spring, the inner edge and the outer edge on the upper surface of the clamping spring are 30-60 degree bevels and are in sliding fit with the bevels of the upper convex part.

[0013] The force-bearing clamping spring is an open C-shaped clamping spring, the edge on the outer periphery of the upper surface of the force-bearing clamping spring and the edge on the lower surface of the inner periphery are 30-60 degree bevels, the edge on the outer periphery of the upper surface of the force-bearing clamping spring is in sliding fit with the wall thickness abrupt change, and the edge on the lower surface of the inner periphery of the force-bearing clamping spring is in sliding fit with the lower convex part of the release sleeve.

[0014] An inner compression spring is mounted between the inner periphery of the release sleeve and the hollow pressure rod, the upper part of the inner compression spring supports the release sleeve, and the lower part of the inner compression spring is supported on the pressure rod support platform.

[0015] The stiffness of the buffer piston compression spring is k1, the stiffness of the support piston compression spring is k2, and the axial stiffness of the hollow compression rod and the positioning rod is k3; the stiffness k1 of the buffer piston compression spring and the stiffness k2 of the support piston compression spring are much smaller than the axial stiffness k3 and k4 of the hollow compression rod and the positioning rod.

[0016] Advantages: 1. Fast response speed, significantly reducing the impact force peak value acting on the support device. The present application sets up an independent buffer piston in the traditional hydraulic support structure, and the dynamic response mechanism of the impact acting on it is a pure mechanical direct transmission. When the support is subjected to instantaneous severe impact load, the buffer piston is quickly retracted, prolonging the action time of the impact force, thereby reducing the impact force peak value acting on the hydraulic support structure. It does not need to wait for the hydraulic pressure to accumulate and overcome the pre-tightening force of the valve core spring before opening, like the traditional pressure valve. This pure mechanical response mechanism fundamentally eliminates the opening delay problem of the pressure valve, realizes the response of nearly instantaneous reduction of pressure peak value, and is especially suitable for coping with the common and destructive rapid impact pressure in coal mining.

[0017] 2. Strong impact resistance, effectively protecting the core components. The buffer piston in the present application serves as an independent energy absorption unit, which can convert the instantaneous huge impact energy into potential energy of the buffer spring through the compression stroke of the buffer piston. This process effectively absorbs the impact energy, avoiding the direct transmission of most of the impact force to the support piston and the hydraulic cylinder, thereby fundamentally preventing the cylinder explosion accident of the main hydraulic cylinder due to the sudden rise of pressure, as well as the bending, deformation or rupture of the support column, ensuring the safety of underground operation.

[0018] 3. Provides controllable buffer protection. The buffer piston stroke, compression spring and compression rod stiffness in the present application are pre-set, which can be designed accurately to match the protection needs of different geological conditions and impact levels by designing the buffer characteristics (such as buffer force-displacement curve, etc.) of the device. The functions of the support system and the buffer piston are separated in structure. When the support system is working normally, the buffer piston is locked in the support piston, ensuring the stiffness and stability of the support, and only when it encounters impact, the buffer piston starts to work. This pure mechanical buffer mechanism makes the support device more flexible and intelligent when resisting impact. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 is a structural schematic diagram of the present application.

[0020] Figure 2 is a structural schematic diagram of the buffer device in the structure of the present application.

[0021] Figure 3 is a working process principle diagram of the structure of the present application.

[0022] In the figure: buffer piston 1, buffer piston bottom hole 1-1, wall thickness mutation 1-2, buffer piston top surface 1-3, force bearing piston 2, hollow pressure rod 3, pressure rod hole 3-1, pressure rod support platform 3-2, positioning rod 4, consolidation sleeve 5, positioning pin 5-1, inner positioning sleeve 6, outer positioning sleeve 7, release sleeve 8, upper convex part 8-1, middle concave part 8-2, lower convex part 8-3, snap spring 9, force bearing snap spring 10, buffer piston compression spring 11, support piston compression spring 12, inner compression spring 13, hydraulic cylinder 14, hydraulic emulsion 15, gasket spring 16. DETAILED DESCRIPTION

[0023] In order to more clearly illustrate the overall concept of the present application, the following will be described in detail in conjunction with the accompanying drawings.

[0024] The support device with a buffer piston of the present application comprises a hydraulic cylinder 14, a force bearing piston 2 located in the hydraulic cylinder 14, a buffer piston 1 located in the force bearing piston 2, a buffer device provided in the buffer piston 1, and a hollow pressure rod 3 provided in the center of the buffer device, the lower part of the hollow pressure rod 3 passing through the buffer piston bottom hole 1-1 in the bottom of the buffer piston 1 and being supported at the bottom of the force bearing piston 2; a support piston compression spring 12 is provided in the force bearing piston 2 below the buffer piston 1, and a buffer piston compression spring 11 is provided in the upper part of the buffer device in the buffer piston 1, the upper part of the buffer piston compression spring 11 being supported on the buffer piston top surface 1-3 at the top of the buffer piston 1. The buffer piston 1 is a cylindrical cavity with variable wall thickness, i.e. the inner diameter of the upper half of the buffer piston 1 is smaller than the inner diameter of the lower half, and the inner diameter of the upper half is connected and transitioned to the inner diameter of the lower half by a conical frustum-shaped wall thickness mutation 1-2, the center of the bottom of the buffer piston 1 is provided with a buffer piston bottom hole 1-1, and the top is provided with a buffer piston top surface 1-3.

[0025] The buffer device takes the pressure rod support platform 3-2 as the base piece, the hollow pressure rod 3 is fixedly connected in the center of the pressure rod support platform 3-2, the release sleeve 8 is provided on the outer periphery of the hollow pressure rod 3 above the pressure rod support platform 3-2, the upper part of the release sleeve 8 is provided with an inner positioning sleeve 6, and the outer periphery of the inner positioning sleeve 6 is provided with an outer positioning sleeve 7.

[0026] The hollow pressure rod 3 is equipped with a positioning rod 4, and a pressure rod hole 3-1 is provided on the hollow pressure rod 3. The upper end of the positioning rod 4 is connected to the fixing sleeve 5. The fixing sleeve 5 is equipped with a positioning pin 5-1, which passes through the pressure rod hole 3-1 on the hollow pressure rod 3 and is fixed to the inner positioning sleeve 6 and the outer positioning sleeve 7 respectively. The release sleeve 8 has an upper convex part 8-1 at the top, a middle concave part 8-2 in the middle, and a lower convex part 8-3 at the bottom. A retaining spring 9 is provided between the middle concave part 8-2 and the outer positioning sleeve 7, and a load-bearing retaining spring 10 is provided between the middle concave part 8-2 and the buffer piston 1. A washer spring 16 is provided between the retaining spring 9 and the load-bearing retaining spring 10. The retaining spring 9 is an open C-shaped retaining spring, and the inner and outer edges of the retaining spring 9 are inclined surfaces of 30-60 degrees (preferably 45 degrees), which slide in cooperation with the inclined surfaces of the upper convex part 8-1. The load-bearing retaining spring 10 is an open C-shaped retaining spring. The upper edge of the outer periphery and the lower edge of the inner periphery of the load-bearing retaining spring 10 are inclined surfaces of 30-60 degrees (preferably 45 degrees). The upper edge of the outer periphery of the load-bearing retaining spring 10 is in sliding fit with the wall thickness abrupt change point 1-2; the lower edge of the inner periphery of the load-bearing retaining spring 10 is in sliding fit with the lower protrusion 8-3 of the release sleeve 8. An inner pressure spring 13 is installed between the inner periphery of the release sleeve 8 and the hollow pressure rod 3. The upper part of the inner pressure spring 13 supports the release sleeve 8, and the lower part of the inner pressure spring 13 is supported on the pressure rod support platform 3-2. The stiffness of the buffer piston spring 11 is k1, the stiffness of the supporting piston spring 12 is k12, and the axial stiffnesses of the hollow pressure rod 3 and the positioning rod 4 are k3 and k4, respectively. The stiffness k1 of the buffer piston spring 11 and the stiffness k2 of the supporting piston spring 12 are much smaller than the axial stiffness k3 and k4 of the hollow pressure rod 3 and the positioning rod 4.

[0027] During the operation of the support device, the inner positioning sleeve 6 and the outer positioning sleeve 7 are always fixed to the positioning rod 4, maintaining their positions.

[0028] When the buffer piston 1 is not under pressure, i.e., P=0 ( Figure 3 In the middle state 1), the buffer piston spring 11 in the buffer piston 1 and the support piston spring 12 in the load-bearing piston 2 are in the initial free state. The retaining spring 9 is located in the concave part 8-2 of the release sleeve 8, pressing against the inner positioning sleeve 6 and constrained in the outer positioning sleeve 7. The load-bearing retaining spring 10 is in the free state. The upper edge slope of its outer periphery contacts the abrupt change in wall thickness 1-2 of the buffer piston 1, the lower edge slope of its inner periphery contacts the lower convex part 8-3 of the release sleeve 8, and the bottom contacts the pressure rod support platform 3-2 of the hollow pressure rod 3.

[0029] When the buffer piston 1 is subjected to pressure P1, the piston wall thickness abruptly changes at point 1-2, causing it to move downwards. This compresses the load-bearing retaining ring 10, which in turn causes the release sleeve 8 and retaining ring 9 to move downwards. This pressure also compresses the pressure rod support platform 3-2, causing the hollow pressure rod 3 to undergo a very small axial compression deformation. Figure 3When the pressure on the buffer piston 1 is less than the set load Pc, the snap spring 9 is still in the constrained state in the outer positioning sleeve 7. At this time, the support stiffness of the buffer piston 1 is the axial stiffness k3 of the hollow compression rod 3, and the descending displacement value is consistent with the deformation value of the hollow compression rod 3. The support reaction force provided by the buffer piston 1 is P1, and both the buffer piston 1 and the supporting piston 2 are in the static support state.

[0030] When the impact load P2 on the buffer piston 1 is greater than the set load Pc, Figure 3 In the middle state 3, the wall thickness mutation 1-2 of the buffer piston 1 continues to press the supporting snap spring 10, the release sleeve 8 and the hollow compression rod 3 to move downward. At this time, the snap spring 9 in the release sleeve 8 moves out of the outer positioning sleeve 7 and is released, thereby releasing the constraint on the release sleeve 8. Meanwhile, the wall thickness mutation 1-2 of the buffer piston 1 presses the supporting snap spring 10 into the recess 8-2 in the release sleeve 8, and the snap spring 9 contacts the convex part 8-1 on the release sleeve 8. At this time, the supporting snap spring 10 has released the constraint on the buffer piston 1, and the hollow compression rod 3 changes from the compressed state to the free state. The buffer piston 1 moves downward under the combined action of the external load P2, the buffer spring 11 and the supporting piston spring 12. At this time, the support stiffness of the buffer piston 1 changes from k3 to k1+k2, and the buffer piston 1 rapidly moves downward, thereby reducing the peak value of the impact force acting on the supporting piston 2, and further avoiding the cylinder explosion caused by the sharp increase of the pressure of the hydraulic emulsion 15 in the hydraulic cylinder 14.

[0031] After the external impact, the external load on the buffer piston 1 is P3, and the buffer piston 1 continues to move downward. When it moves to the lowest point, Figure 3 In the middle state 4, the top surface 1-3 of the buffer piston 1 collides with the top surface of the supporting piston 2, and the supporting snap spring 10, the buffer spring 11 and the inner spring 13 are in the maximum compression position. At this time, the support force of the supporting piston 2 is the same as the external pressure P3, and both the buffer piston 1 and the supporting piston 2 are in the static support state.

[0032] When the external pressure P4=0, the buffer piston 1 returns to the initial state under the action of the buffer spring 11 and the supporting piston spring 12, Figure 3 In the middle state 1, the snap spring 9 and the supporting snap spring 10 return to the initial state, and the release sleeve 8 returns to the initial state under the action of the inner spring 13.

Claims

1. A support device with a buffer piston, characterized in that... The device includes a hydraulic cylinder (14), a load-bearing piston (2) located in the hydraulic cylinder (14), a buffer piston (1) located in the load-bearing piston (2), a buffer device is provided inside the buffer piston (1), the lower part of the hollow pressure rod (3) in the center of the buffer device passes through the buffer piston bottom hole (1-1) at the bottom of the buffer piston (1) and is supported at the bottom inside the load-bearing piston (2); a support piston spring (12) is provided in the load-bearing piston (2) below the buffer piston (1), a buffer piston spring (11) is provided on the upper part of the buffer device inside the buffer piston (1), and the upper part of the buffer piston spring (11) is supported on the top surface (1-3) of the buffer piston at the top of the buffer piston (1).

2. The support device with a buffer piston according to claim 1, characterized in that... The buffer piston (1) is a cylindrical cavity with variable wall thickness, that is, the inner diameter of the upper half of the buffer piston (1) is smaller than the inner diameter of the lower half. The inner diameter of the upper half and the inner diameter of the lower half are connected and transitioned by a truncated cone-shaped wall thickness change point (1-2). The bottom center of the buffer piston (1) is provided with a buffer piston bottom hole (1-1), and the top is provided with a buffer piston top surface (1-3).

3. The support device with a buffer piston according to claim 2, characterized in that... The buffer device is based on a pressure rod support platform (3-2). A hollow pressure rod (3) is fixedly connected to the center of the pressure rod support platform (3-2). A release sleeve (8) is provided on the outer periphery of the hollow pressure rod (3) above the pressure rod support platform (3-2). An inner positioning sleeve (6) is provided on the upper part of the release sleeve (8). An outer positioning sleeve (7) is provided on the outer periphery of the inner positioning sleeve (6).

4. The support device with a buffer piston according to claim 3, characterized in that... The hollow pressure rod (3) is provided with a positioning rod (4) and a pressure rod hole (3-1) on the hollow pressure rod (3). The upper end of the positioning rod (4) is connected to the fixing sleeve (5). The fixing sleeve (5) is provided with a positioning pin (5-1). The positioning pin (5-1) passes through the pressure rod hole (3-1) on the hollow pressure rod (3) and is fixed to the inner positioning sleeve (6) and the outer positioning sleeve (7) respectively.

5. The support device with a buffer piston according to claim 4, characterized in that... The release sleeve (8) has an upper convex part (8-1), a middle concave part (8-2), and a lower convex part (8-3) at the top. A retaining ring (9) is provided between the middle concave part (8-2) and the outer positioning sleeve (7). A load-bearing retaining ring (10) is provided between the middle concave part (8-2) and the buffer piston (1). A washer spring (16) is provided between the retaining ring (9) and the load-bearing retaining ring (10).

6. The support device with a buffer piston according to claim 5, characterized in that... The snap ring (9) is an open C-shaped snap ring. The inner and outer edges of the snap ring (9) are inclined surfaces of 30-60 degrees, which slide in cooperation with the inclined surface of the upper convex part (8-1).

7. The support device with a buffer piston according to claim 6, characterized in that... The load-bearing circlip (10) is an open C-shaped circlip. The upper edge of the outer periphery and the lower edge of the inner periphery of the load-bearing circlip (10) are inclined surfaces of 30-60 degrees. The upper edge of the outer periphery of the load-bearing circlip (10) is in sliding fit with the abrupt change in wall thickness (1-2). The lower edge of the inner periphery of the load-bearing circlip (10) is in sliding fit with the lower protrusion (8-3) of the release sleeve (8).

8. The support device with a buffer piston according to claim 7, characterized in that... An inner pressure spring (13) is installed between the inner circumference of the release sleeve (8) and the hollow pressure rod (3). The upper part of the inner pressure spring (13) supports the release sleeve (8), and the lower part of the inner pressure spring (13) is supported on the pressure rod support platform (3-2).

9. The support device with a buffer piston according to claim 8, characterized in that... The stiffness of the buffer piston spring (11) is k1, the stiffness of the supporting piston spring (12) is k2, and the axial stiffnesses of the hollow pressure rod (3) and the positioning rod (4) are k3 and k4, respectively. The stiffness k1 of the buffer piston spring (11) and the stiffness k2 of the supporting piston spring (12) are much smaller than the axial stiffness k3 and k4 of the hollow pressure rod (3) and the positioning rod (4).

Images