Oil return buffer device and impact test system with same

Abstract

The invention discloses an oil return buffer device and an impact test system with the same. The oil return buffer device comprises a cylinder barrel assembly, a buffer piston, an impact piston, an overflow detection loop, an oil charge detection loop and an air charge detection loop. A first inner barrel cavity, a damping hole and a buffering cavity are formed in the cylinder barrel assembly, and the buffering cavity is connected with an oil filling detection loop. The buffer piston is arranged in the first inner cylinder cavity so as to divide the first inner cylinder cavity into a first side cavity and a second side cavity. The buffer piston is provided with a second inner cylinder cavity, the impact piston is arranged in the second inner cylinder cavity to divide the second inner cylinder cavity into an oil return cavity and an air cavity, the oil return cavity communicates with the first side cavity, and the air cavity communicates with the inflation detection loop. The device has the obvious impact stage and the buffering stage, the instant impact pressure is rapidly reduced in the impact stage, the deceleration back pressure is obtained through oil pressure loss in the buffering stage, the buffering effect is obvious and easy to control, and the device is suitable for the field of high-speed large-flow oil return buffering of an impact hydraulic system.

Description

Technical Field

[0001] The present invention relates to the technical field of high-speed hydraulic equipment, and in particular, to an oil return buffer device. In addition, the present invention also relates to an impact test system comprising the oil return buffer device. Background Art

[0002] In various engineering applications such as high-speed impact tests or high-speed ejection devices, it is usually necessary to accelerate test blocks or test objects of different masses to the target speed within a certain stroke. The hydraulic system has the advantages of large load and compact structure, and is an ideal acceleration system. During the acceleration process, the hydraulic system often drives the return oil to accelerate together, and has the characteristics of high speed and large flow. In order to prevent the high-speed and large-flow return oil from damaging the hydraulic system, the return oil needs to be buffered and decelerated. As a buffering actuator, the buffer device should have the characteristics of small return oil resistance in the acceleration stage, large bearing capacity in the buffer stage, and fast speed.

[0003] Patent 1: CN220378618U discloses a buffer oil storage device and impact test system, including a cylinder and a piston, the piston is used to divide the inner cavity of the cylinder into an air cavity located at the first end of the cylinder and an oil cavity located at the second end of the cylinder; the end surface of the first end of the cylinder is provided with an exhaust hole connected to the inner wall of the first end of the cylinder, and the second end of the cylinder is used to connect and communicate with the oil source of the acceleration system; an air supply device is provided outside the cylinder body, which is used to fill the air cavity of the cylinder with inert gas so that when the oil source fills the oil cavity with hydraulic oil under the action of the acceleration system, the piston forms a buffer deceleration when moving toward the first end of the cylinder; the cylinder is also provided with an adjustment component, which is used to adjust the stroke of the piston and then adjust the oil storage capacity of the cylinder. In this patented device, buffer deceleration is mainly performed by inert gas, there is no obvious impact stage and buffer stage, the return oil resistance in the impact stage is large, and the deceleration back pressure is obtained only by gas pressure loss in the buffer stage, and the buffer effect is difficult to control.

[0004] Patent 2: CN117432452A discloses an anti-impact hydraulic support device, a hydraulic support and a control method, wherein the support device comprises: a first sleeve; a piston rod, which is mounted in the first sleeve, and the piston rod has a first piston mounted in the first sleeve, and the first piston divides the first sleeve into a first chamber and a second chamber, and the first chamber is connected to the first pipeline; the support device also comprises: a first solenoid valve, which is mounted in the first chamber of the first sleeve; a sensor, which can monitor the impact of the top of the piston rod; a control unit, which is connected to the sensor and the first solenoid valve, and the control unit controls the first solenoid valve to open when the value monitored by the sensor is greater than the set threshold value, so that the medium on the lower side of the first piston can enter the upper side of the first piston. This patented device is mainly used to prevent external physical impacts, such as roof support in coal mining, and instantaneous impacts generated by support structures during some building construction and civil engineering construction, and is not suitable for the high-speed and large-flow oil return buffer field of impact hydraulic systems.

[0005] Patent 3: CN105715612A discloses a throttling buffer oil cylinder with an integrated buffer cylinder bottom, including a cylinder barrel, a cylinder bottom, a piston and a piston rod, a buffer plunger is provided on the side of the cylinder bottom facing the piston, a buffer cavity is provided on the side of the piston facing the cylinder bottom, when the piston approaches the end of the stroke, the buffer plunger extends into the buffer cavity, the buffer plunger is a hollow structure, and an oil hole connected to the inner cavity of the buffer plunger is provided on the cylinder bottom. In this patent, it is suitable for low-speed buffering of conventional oil cylinders, and cannot meet the buffering requirements of high-speed and large-flow oil return.

[0006] In the prior art, there are three main types of oil return buffering technologies for high-speed and large-flow return. The first is to use the medium flow resistance between the piston gap and the inner surface of the cylinder body for buffering braking. The instantaneous buffering pressure of the buffer chamber in this method cannot be reduced. As time goes by and the number of buffering times increases, the higher buffering pressure will cause damage to the piston and the cylinder, such as patent CN220378618U; the second is a throttling buffering method using an integrated buffer cylinder bottom to integrate the buffer position on the piston. This method is only suitable for low-speed oil cylinders and cannot meet the buffering requirements of high-speed and large-flow return oil, such as patent CN105715612A; the third is to connect a buffer device to the acceleration device to perform buffering by throttling and accumulators. The existing buffer devices using this technology have large resistance in the acceleration stage and cannot meet the needs of instantaneous large flow during high-speed impact. Summary of the invention

[0007] The present invention provides an oil return buffer device and an impact test system having the same, so as to solve the technical problems existing in the existing devices and systems, namely, there is no obvious impact stage and buffer stage, the oil return resistance in the impact stage is large, the deceleration back pressure is obtained only by gas pressure loss in the buffer stage, the buffer effect is difficult to control, and the buffering requirements of high-speed and large-flow oil return cannot be met.

[0008] The technical solution adopted by the present invention is as follows:

[0009] An oil return buffer device comprises: a cylinder assembly, a buffer piston, an impact piston, an overflow detection circuit, an oil filling detection circuit and an air filling detection circuit; the cylinder assembly is in a hollow cylindrical shape for connecting to an impact test system, and has a first inner cylinder cavity arranged along the axial direction, and a buffer cavity connected to the first inner cylinder cavity through a damping hole, the buffer cavity is connected to the oil filling detection circuit, so as to perform oil filling and pressure detection on the buffer cavity through the oil filling detection circuit; the buffer piston is slidably arranged in the first inner cylinder cavity to separate the first inner cylinder cavity into a first side cavity and a second side cavity located on both sides thereof and not connected cavity, and the second side cavity is connected to the buffer cavity through the damping hole; the buffer piston is hollow cylindrical, and has a second inner cylinder cavity arranged along the axial direction, the impact piston is slidably arranged in the second inner cylinder cavity to separate the second inner cylinder cavity into a return oil cavity and an air cavity located on both sides thereof and not connected, and the return oil cavity is connected to the first side cavity for connecting with the impact return oil of the impact test system, the return oil cavity is also connected to an overflow detection circuit for the oil in the return oil cavity to overflow outward and for pressure detection, and the air cavity is connected to an inflation detection circuit to inflate the air cavity, detect the pressure and discharge the gas in the air cavity to the atmosphere through the inflation detection circuit.

[0010] Furthermore, the oil return buffer device also includes a buffer piston rod axially connected to the buffer piston, and the buffer piston rod is located in the second side cavity so that the second side cavity forms a rod cavity; the cylinder assembly includes a hollow cylindrical cylinder, a first end cover for closing the second end of the cylinder, and a first end cover cylinder body axially connected to the first end cover for accommodating the buffer piston rod, and the first end of the cylinder is connected to the oil return cavity; the buffer piston is slidably arranged in the inner cylinder cavity of the cylinder, and the two are also in sealed contact through a sealing ring; the buffer piston rod axially penetrates the rod cavity and then extends into the first end cover cylinder body, and the buffer piston rod and the first end cover cylinder body are also in sealed contact through a sealing ring.

[0011] Furthermore, the first end cover cylinder is in the shape of a hollow cylinder with both ends connected; the cylinder assembly also includes a third end cover for closing the free end of the first end cover cylinder, and the third end cover is provided with an air hole set through it, and the air hole is connected to the inflation detection circuit; the buffer piston rod is in the shape of a hollow cylinder with both ends connected, and the two ends of the buffer piston rod are respectively connected to the air cavity and the inner cylinder cavity of the first end cover cylinder, so that the air cavity is connected to the inner cylinder cavity of the buffer piston rod and the inner cylinder cavity of the first end cover cylinder in turn.

[0012] Furthermore, the inflation detection circuit includes an air supply pipeline connected to the air hole, and a second needle valve, an air cavity pressure sensor and an electric ball valve connected to the air supply pipeline.

[0013] Furthermore, the cylinder assembly also includes a second end cover which is sleeved on the outer circle of the first end cover barrel and is located outside the first end cover. The second end cover is concavely arranged to form a buffer cavity between it and the first end cover. The second end cover is also provided with a buffer oil port which is penetrated and connected to the buffer cavity, and the buffer oil port is connected to the oil filling detection circuit; the damping hole is a multi-circle annular hole which is opened on the first end cover and is in the shape of a concentric ring, so that the rod cavity and the buffer cavity are connected through the multi-circle annular hole.

[0014] Furthermore, the cylinder assembly also includes a second end cover which is annular and sealingly sleeved on the outer circle of the cylinder. The second end cover is concavely arranged to form a buffer cavity between it and the cylinder. The second end cover is also provided with a buffer oil port which is arranged through and connected to the buffer cavity. The buffer oil port is connected to the oil filling detection circuit. The damping hole is a multi-circle damping hole group which is sequentially opened on the cylinder along the axial direction. Each circle of the damping hole group includes a plurality of damping holes which are sequentially spaced along the circumferential direction, so that the rod cavity and the buffer cavity are connected through the damping hole group.

[0015] Furthermore, the apertures of the damping holes of the multi-circle damping hole group gradually decrease along the damping sliding direction of the buffer piston.

[0016] Furthermore, the oil filling detection circuit includes an oil delivery pipeline connected to the buffer oil port, and a ball valve and a buffer chamber pressure sensor connected to the oil delivery pipeline.

[0017] Furthermore, the oil filling detection circuit also includes a piston accumulator connected to the oil pipeline, and the piston accumulator is provided with a separate air filling chamber and an oil filling chamber. The air filling chamber is also connected to an external inert gas source through a first needle valve, and the oil filling chamber is connected to the buffer oil port.

[0018] Furthermore, the cylinder assembly also includes a piston cover located in the first side cavity, the piston cover is used to abut the corresponding end of the buffer piston along the axial direction, and the piston cover partially extends into the oil return cavity to abut against the impact piston to prevent the impact piston from sliding out of the buffer piston.

[0019] Furthermore, the overflow detection circuit includes an overflow pipeline connected to the oil return chamber, and an oil return chamber pressure sensor, an electromagnetic ball valve and an overflow valve which are sequentially connected to the overflow pipeline.

[0020] According to another aspect of the present invention, there is also provided an impact test system, wherein the oil return pipe or the high-speed switch valve group is connected to the oil return buffer device as described above.

[0021] The present invention has the following beneficial effects:

[0022] In the oil return buffer device of the present invention, a dual piston of an impact piston and a buffer piston is used to realize acceleration and buffering action. An impact piston is designed inside the buffer piston. In the impact stage, one end of the impact piston is a high-speed and large-flow oil return, and the other end is an air cavity connected to the atmosphere, so that the impact hydraulic system has almost no oil return back pressure in the acceleration stage. When the impact piston moves to the end of the stroke, it enters the buffer stage, and the buffer piston plays a deceleration and buffering role to realize the buffering and deceleration of the oil. Therefore, in the oil return buffer device of the present invention, through the cooperation of the impact piston and the buffer piston, the whole impact buffering process has obvious impact stage and buffer stage. In the impact stage, the oil return resistance is small (the air cavity is connected to the atmosphere), and the instantaneous impact pressure in the impact stage is rapidly reduced, which is not easy to cause damage to the cylinder assembly and the piston. In the buffer stage, the deceleration back pressure is obtained by relying on the oil pressure loss. The buffering effect is obvious and easy to control, which is suitable for the high-speed and large-flow oil return buffering field of the impact hydraulic system.

[0023] In the impact test system of the present invention, the entire impact buffering process has obvious impact stage and buffering stage. The return oil resistance in the impact stage is small, and the instantaneous impact pressure in the impact stage decreases rapidly, which is not easy to cause damage to the cylinder assembly and the piston. In the buffering stage, the deceleration back pressure is obtained by relying on the oil pressure loss. The buffering effect is obvious and easy to control, and it is suitable for the high-speed and large-flow return oil buffering field of the impact hydraulic system.

[0024] In addition to the above-described purposes, features and advantages, the present invention has other purposes, features and advantages. The present invention will be further described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The drawings constituting a part of this application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0026] Figure 1 It is a schematic diagram of the structure of the oil return buffer device before the impact starts in a preferred embodiment of the present invention;

[0027] Figure 2 The structure of the oil return buffer device of the preferred embodiment of the present invention at the beginning of buffering is shown in FIG. Figure 1 ;

[0028] Figure 3 It is a structural schematic diagram of the impact piston and the buffer piston in the oil return buffer device of the preferred embodiment of the present invention extending to the limit position;

[0029] Figure 4 The structure of the oil return buffer device of the preferred embodiment of the present invention at the beginning of buffering is shown in FIG. Figure 2 .

[0030] Legend:

[0031] 100, impact return oil; 110, return oil chamber; 120, return oil chamber pressure sensor; 130, electromagnetic ball valve; 140, overflow valve; 210, cylinder barrel; 211, first end face of cylinder body; 212, second end face of cylinder body; 213, first stop; 220, piston cover; 221, second stop; 230, impact piston; 240, buffer piston; 241, buffer piston rod; 242, rod chamber; 250, first end cover; 251, damping Hole; 252, first end cover cylinder; 260, second end cover; 261, buffer oil port; 262, buffer cavity; 270, third end cover; 271, air hole; 272, air cavity; 300, oil filling detection circuit; 310, first needle valve; 320, piston accumulator; 330, ball valve; 340, buffer cavity pressure sensor; 400, inflation detection circuit; 410, second needle valve; 420, air cavity pressure sensor; 430, electric ball valve. DETAILED DESCRIPTION

[0032] The embodiments of the present invention are described in detail below with reference to the accompanying drawings. However, the present invention can be implemented in many different ways as defined and covered below.

[0033] Reference Figure 1 and Figure 4 The preferred embodiment of the present invention provides an oil return buffer device, comprising: a cylinder assembly, a buffer piston 240, an impact piston 230, an overflow detection circuit, an oil filling detection circuit 300 and an air filling detection circuit 400. The cylinder assembly is in a hollow cylindrical shape for connection with an impact test system, and has a first inner cylinder cavity arranged along the axial direction, and a buffer cavity 262 connected to the first inner cylinder cavity through a damping hole 251, and the buffer cavity 262 is connected to the oil filling detection circuit 300, so as to fill the buffer cavity 262 with oil and perform pressure detection through the oil filling detection circuit 300. The buffer piston 240 is slidably disposed in the first inner cylinder cavity to separate the first inner cylinder cavity into a first side cavity and a second side cavity located on both sides thereof and not connected, and the second side cavity is connected to the buffer cavity 262 through the damping hole 251. The buffer piston 240 is hollow cylindrical and has a second inner cylinder cavity arranged along the axial direction. The impact piston 230 is slidably set in the second inner cylinder cavity to divide the second inner cylinder cavity into a return oil cavity 110 and an air cavity 272 located on both sides thereof and not connected. The return oil cavity 110 is connected to the first side cavity and is used to connect with the impact return oil 100 of the impact test system. The return oil cavity 110 is also connected to an overflow detection circuit for the lubricating oil in the return oil cavity 110 to overflow and for pressure detection. The air cavity 272 is connected to the inflation detection circuit 400 to inflate the air cavity 272, detect the pressure, and discharge the gas in the air cavity 272 to the atmosphere through the inflation detection circuit 400.

[0034] The oil return buffer device of the present invention is divided into a preparation stage, an impact stage, and a buffer stage. The specific working process is as follows:

[0035] Preparation stage: the oil return buffer device of the present invention is arranged at the oil return position of the high-speed switch valve of the impact system, and the impact return oil 100 is connected to the oil return of the high-speed switch valve. At this time, the high-speed switch valve is not opened, the overflow detection circuit is opened and the pressure is set to 10-20 bar;

[0036] The oil filling detection circuit 300 is opened, and the external high-pressure oil source fills the buffer chamber 262 and the second side chamber with oil, so that the buffer piston 240 retracts to the rightmost position, such as Figure 1 As shown, when the overflow detection circuit detects that the pressure of the oil return chamber 110 is maintained at the first set value, it is considered that the buffer piston 240 is retracted into place, and then the oil filling detection circuit 300 is closed after the pressure of the buffer chamber 262 is detected to be maintained at the target pressure.

[0037] Open the inflation detection circuit 400, connect high-pressure nitrogen to inflate the air chamber 272, and the inflation pressure is 10-15 bar higher than the impact return oil pressure, so that the impact piston 230 retracts to the rightmost position, such as Figure 1 As shown, when the overflow detection circuit detects that the pressure of the oil return chamber 110 is maintained at the second set value, it is considered that the impact piston 230 is retracted into place, and then the pressure of the air chamber 272 is detected to be maintained at the target pressure and the inflation detection circuit 400 is closed.

[0038] At this point, the preparation stage is over, and the position diagram of the buffer piston 240 and the impact piston 230 is as shown in FIG. Figure 1 shown.

[0039] Impact stage: when the impact command is given, the overflow detection circuit is closed and the inflation detection circuit 400 is opened to connect with the atmosphere. The purpose of closing the overflow detection circuit is to prevent the buffer oil from being discharged from the circuit, and the purpose of opening the inflation detection circuit 400 is to quickly discharge the high-pressure gas in the air cavity 272 and connect it to the atmosphere, so as to ensure that there is almost no back pressure when the impact piston 230 slides axially toward the air cavity 272 during the impact stroke; then the main valve core of the impact system high-speed switching valve is opened, and the impact return oil 100 is connected to the impact system return oil, so that the impact piston 230 accelerates to slide toward the air cavity 272. Since the air cavity 272 is connected to the atmosphere, the pressure required to push the impact piston 230 to move is very small, so the pressure loss of the impact system return oil is small and the energy loss is small; when the impact piston 230 moves to the end of the stroke, the impact stage ends and enters the buffer stage. At this time, the position diagram of the buffer piston 240 and the impact piston 230 is as shown in the figure Figure 2 shown.

[0040] Buffering stage: the impact piston 230 moves to the root of the buffer piston 240, and drives the buffer piston 240 to extend in the direction away from the impact return oil 100. At this time, the flow rate of the oil in the return oil chamber 110 reaches a maximum value. During the extension of the buffer piston 240, due to the throttling buffering effect of the damping hole 251, the greater the extension stroke of the buffer piston 240, the greater the pressure in the second side chamber, and the oil in the buffer piston 240 and the return oil chamber 110 is decelerated and buffered. Finally, before the buffer piston 240 reaches the end of the stroke, the oil in the buffer piston 240 and the return oil chamber 110 is decelerated to 0, and then begins to move in the retraction direction. After multiple layers of rebound, the buffer piston 240 finally stabilizes at the equilibrium position; at this point, the buffering stage ends, and the position diagram of the buffer piston 240 and the impact piston 230 moving to the extreme position is shown in Figure 3 shown.

[0041] In the oil return buffer device of the present invention, a dual piston of an impact piston 230 and a buffer piston 240 is used to realize acceleration and buffering actions. The impact piston 230 is designed inside the buffer piston 240. In the impact stage, one end of the impact piston 230 is a high-speed and large-flow oil return, and the other end is an air cavity 272 connected to the atmosphere, so that the impact hydraulic system has almost no oil return back pressure in the acceleration stage. When the impact piston 230 moves to the end of the stroke, it enters the buffer stage. The buffer piston 240 plays a deceleration and buffering role to achieve buffering and deceleration of the oil. Therefore, in the oil return buffer device of the present invention, through the cooperation of the impact piston 230 and the buffer piston 240, the entire impact buffering process has obvious impact stage and buffering stage. The oil return resistance in the impact stage is small (the air cavity 272 is connected to the atmosphere), and the instantaneous impact pressure in the impact stage is rapidly reduced, which is not easy to cause damage to the cylinder assembly and the piston. In the buffer stage, the deceleration back pressure is obtained by relying on the oil pressure loss. The buffering effect is obvious and easy to control, which is suitable for the high-speed and large-flow oil return buffering field of the impact hydraulic system.

[0042] Alternatively, if Figure 1As shown, the oil return buffer device also includes a buffer piston rod 241 axially connected to the buffer piston 240, and the buffer piston rod 241 is located in the second side cavity so that the second side cavity forms a rod cavity 242. The cylinder assembly includes a hollow cylindrical cylinder 210, a first end cover 250 for closing the second end of the cylinder 210, and a first end cover cylinder body 252 axially connected to the first end cover 250 for accommodating the buffer piston rod 241. The first end of the cylinder 210 is connected to the oil return cavity 110. The buffer piston 240 is slidably disposed in the inner cylinder cavity of the cylinder 210, and the two are also in sealing contact through a sealing ring. The buffer piston rod 241 is axially penetrated with the rod cavity 242 and then extends into the first end cover cylinder body 252, and the buffer piston rod 241 and the first end cover cylinder body 252 are also in sealing contact through a sealing ring. In this optional solution, the cylinder 210 is cylindrical, and the first end face 211 and the second end face 212 of the cylinder are arranged on the two sides respectively. The cylinder 210 is fixed to the impact system return oil pipe or the high-speed switch valve group through the first end face 211 of the cylinder, and the impact system return oil is connected to the return oil chamber 110; a first stop 213 is arranged in the first end face 211 of the cylinder, and its function is to stop the buffer piston 240 when it retracts; multiple sealing rings are used to seal between the impact piston 230 and the buffer piston 240 to prevent the fluid on both sides of the impact piston 230 from leaking each other; the buffer piston rod 241 and the buffer piston 240 are integrally formed The buffer piston rod 241 has an outer diameter that is 0.2 to 0.6 times that of the buffer piston 240. The buffer piston 240 adopts a long piston design, which ensures the impact stroke of the internal impact piston 230 on the one hand, and enhances the guiding effect on the other hand. When the impact piston 230 hits the buffer piston 240, the two can slide smoothly together to prevent jamming. The first end cover cylinder 252 and the first end cover 250 are an integrally formed structure. The inner diameter of the first end cover cylinder 252 is slightly larger than the outer diameter of the buffer piston rod 241. The function of the first end cover cylinder 252 is to fully accommodate the buffer piston rod 241 when the buffer rod 240 is extended.

[0043] Alternatively, if Figure 1 As shown, the first end cover cylinder 252 is in the shape of a hollow cylinder with two ends connected. The cylinder assembly also includes a third end cover 270 for sealing the free end of the first end cover cylinder 252, and the third end cover 270 is provided with an air hole 271 that is arranged through, and the air hole 271 is connected to the inflation detection circuit 400. The buffer piston rod 241 is in the shape of a hollow cylinder with two ends connected, and the two ends of the buffer piston rod 241 are respectively connected to the air cavity 272 and the inner cylinder cavity of the first end cover cylinder 252, so that the air cavity 272 is connected to the inner cylinder cavity of the buffer piston rod 241 and the inner cylinder cavity of the first end cover cylinder 252 in sequence.

[0044] Alternatively, if Figure 1As shown, the inflation detection circuit 400 includes an air supply pipeline connected to the air hole 271, and a second needle valve 410, an air cavity pressure sensor 420 and an electric ball valve 430 connected to the air supply pipeline. In this optional solution, the second needle valve 410 is used to connect an external high-pressure gas source to inflate the air cavity 272 so that the impact piston 230 is fully retracted before the impact begins; the air cavity pressure sensor 420 is used to detect the pressure of the air cavity 272; the electric ball valve 430 has a large diameter to minimize the throttling effect, and its function is to quickly discharge the high-pressure gas in the air cavity 272 into the air.

[0045] Alternatively, if Figure 1 As shown, the first embodiment of the cylinder assembly, the cylinder assembly also includes a second end cover 260 which is sleeved on the outer circle of the first end cover barrel 252 and is located outside the first end cover 250. The second end cover 260 is concavely arranged to enclose a buffer cavity 262 between it and the first end cover 250. The second end cover 260 is also provided with a buffer oil port 261 which is penetrated and connected to the buffer cavity 262. The buffer oil port 261 is connected to the oil filling detection circuit 300. The damping hole 251 is a concentric annular multi-circle annular hole opened on the first end cover 250, so that the rod cavity 242 and the buffer cavity 262 are connected through the multi-circle annular hole.

[0046] Alternatively, if Figure 4 As shown, the second embodiment of the cylinder assembly, the cylinder assembly also includes a second end cover 260 which is annular and sealingly sleeved on the outer circle of the cylinder 210, the second end cover 260 is concavely arranged to enclose a buffer chamber 262 between the second end cover 260 and the cylinder 210, and a buffer oil port 261 which is arranged through and connected to the buffer chamber 262 is also opened on the second end cover 260, and the buffer oil port 261 is connected to the oil filling detection circuit 300. The damping hole 251 is a group of multiple circles of damping holes 251 opened in sequence on the cylinder 210 along the axial direction, and each circle of the damping hole 251 group includes a plurality of damping holes 251 arranged in sequence and spaced in the circumferential direction, so that the rod chamber 242 and the buffer chamber 262 are connected through the damping hole 251 group.

[0047] Preferably, if Figure 4As shown, the aperture of the damping hole 251 of the multi-circle damping hole 251 group gradually decreases along the direction of the buffer piston 240 buffering sliding. In this preferred solution, the damping hole 251 is arranged at the position of the rod chamber 242 on the cylinder 210, the opening direction of the damping hole 251 is radial, and the opening diameter of the damping hole 251 becomes smaller and smaller along the extension direction of the buffer piston 240. The second end cover 260 is arranged outside the damping hole 251 to collect the high-pressure hydraulic oil throttled through the damping hole 251 in the rod chamber 242, and the buffer oil port 261 is arranged outside the second end cover 260 to connect the oil filling detection circuit 300. Different from the beneficial effect of the first embodiment, during the buffering process, as the buffer piston 240 extends, the damping hole 251 is partially covered, and the flow area of ​​the hydraulic oil from the rod chamber 242 through the damping hole 251 to the buffer chamber 262 becomes smaller and smaller, the throttling buffering effect is more obvious, and reliable and effective buffering can be achieved.

[0048] Alternatively, if Figure 1 As shown, the oil filling detection circuit 300 includes an oil delivery pipeline connected to the buffer oil port 261, and a ball valve 330 and a buffer chamber pressure sensor 340 connected to the oil delivery pipeline. In this optional solution, the function of the ball valve 330 is to connect an external high-pressure oil source to fill the buffer chamber 262 and the rod chamber 242 with oil and maintain pressure; the buffer chamber pressure sensor 340 is used to detect the pressure of the buffer chamber 262.

[0049] Preferably, if Figure 1 As shown, the oil filling detection circuit 300 also includes a piston accumulator 320 connected to the oil pipeline. The piston accumulator 320 is provided with a separated air filling chamber and an oil filling chamber. The air filling chamber is also connected to an external inert gas source through a first needle valve 310, and the oil filling chamber is connected to the buffer oil port 261. In this preferred solution, the air filling chamber of the piston accumulator 320 is connected to an external high-pressure gas source through the first needle valve 310 to adjust the pre-charge pressure; when working, the damping hole 251 and the piston accumulator 320 are connected in series to achieve deceleration and buffering effects. In the buffering stage, the buffer piston 240 extends so that the oil in the rod chamber 242 passes through the damping hole 251 and enters the buffer chamber 262 and the piston accumulator 320. After double throttling and buffering, the larger the stroke of the buffer piston 240, the higher the pressure in the rod chamber 242, and the more significant the buffer deceleration effect. In the present invention, the entire impact buffering process has obvious impact stage and buffering stage. The return oil resistance in the impact stage is small, and the instantaneous impact pressure in the impact stage decreases rapidly, which is not easy to cause damage to the cylinder assembly and the piston. In the buffering stage, the deceleration and buffering of the buffer piston are achieved by throttling and buffering of the damping hole. The buffer piston is passively extended so that the rod chamber oil passes through the damping hole and enters the buffer chamber and the piston accumulator in turn. After the double throttling and buffering effect, the larger the extension stroke of the buffer piston, the more significant the buffer deceleration effect. The buffering effect of this process is obvious and easy to control, and is suitable for the field of high-speed and large-flow return oil buffering of impact hydraulic systems.

[0050] Alternatively, if Figure 1 As shown, the cylinder assembly further includes a piston cover 220 located in the first side cavity, the piston cover 220 is used to abut the corresponding end of the buffer piston 240 along the axial direction, and the piston cover 220 partially extends into the oil return cavity 110, so as to abut against the impact piston 230 to prevent the impact piston 230 from sliding out of the buffer piston 240. In this optional solution, the outer diameter of the piston cover 220 is 6-12 mm smaller than the outer diameter of the buffer piston 240, and the inner diameter of the piston cover 220 is 10-20 mm smaller than the outer diameter of the impact piston 230. A second stop 221 is arranged on the inner side of the piston cover 220, which is used to abut against the impact piston 230 to limit the position.

[0051] Alternatively, if Figure 1 As shown, the overflow detection circuit includes an overflow pipeline connected to the oil return chamber 110, and an oil return chamber pressure sensor 120, an electromagnetic ball valve 130 and an overflow valve 140 connected in sequence to the overflow pipeline. In this optional solution, the oil return chamber pressure sensor 120 detects the pressure of the oil return chamber 110, the electromagnetic ball valve 130 implements logic control, and the overflow valve 140 controls the oil return chamber pressure through overflow.

[0052] The specific working process of the oil return buffer device of the present invention is as follows:

[0053] Preparation stage: The oil return buffer device is arranged at the oil return position of the high-speed switch valve of the impact system, and the impact return oil 100 is connected to the oil return of the high-speed switch valve. At this time, the high-speed switch valve is not opened, the electromagnetic ball valve 130 is opened, and the pressure of the relief valve 140 is set to 10-20 bar;

[0054] Open the first needle valve 310 and connect the high-pressure nitrogen to fill the air chamber of the piston accumulator with nitrogen. When the pressure reaches the target pressure, close the needle valve. Open the ball valve 330 and connect the high-pressure oil source to fill the buffer chamber 262 and the rod chamber 242 with oil, so that the buffer piston 240 retracts to the first stop 213. When the pressure of the oil return chamber pressure sensor 120 of the impact oil return is detected to be maintained at the set value, it is considered that the buffer piston 240 is retracted into place. Then, after detecting that the pressure of the buffer chamber 262 is maintained at the target pressure, close the ball valve 330.

[0055] Close the electric ball valve 430, open the second needle valve 410 and connect the external high-pressure nitrogen to inflate the air cavity. The inflation pressure is 10-15 bar higher than the impact oil return pressure, so that the impact piston 230 retracts to the second stop 221. When the oil return cavity pressure sensor 120 detects that the pressure remains at the set value, it is considered that the impact piston 230 is retracted. Then, the second needle valve 410 is closed after the air cavity pressure is detected to remain at the target pressure.

[0056] At this point, the preparation stage is over, and the position diagram of the buffer piston 240 and the impact piston 230 is as shown in FIG. Figure 1 shown.

[0057] Impact phase: When an impact command is given, commands to close the electromagnetic ball valve 130 and to open the electric ball valve 430 are given at the same time. The purpose of closing the electromagnetic ball valve 130 is to prevent the buffer oil from being discharged from the relief valve 140, and the purpose of opening the electric ball valve 430 is to quickly discharge the high-pressure gas in the air cavity and connect it to the atmosphere, ensuring that there is almost no back pressure when the impact piston 230 slides axially toward the air cavity during the impact stroke. Subsequently, the main valve core of the impact system high-speed switching valve is opened, and the impact return oil is connected to the impact system return oil, so that the impact piston 230 accelerates to slide toward the air cavity. Since the air cavity is connected to the atmosphere, the pressure required to push the impact piston 230 to move is very small, so the pressure loss of the impact system return oil is small, and the energy loss is small. When the impact piston 230 moves to the end of the stroke, the impact phase ends and enters the buffer phase. At this time, the position diagram of the buffer piston 240 and the impact piston 230 is as shown in the figure. Figure 2 shown.

[0058] Buffering stage: the impact piston 230 moves to the root of the buffer piston rod 241, and drives the buffer piston 240 to extend in the direction away from the impact return oil 100. At this time, the flow rate of the oil in the return oil chamber 110 reaches the maximum value. During the extension of the buffer piston 240, due to the dual throttling and buffering effects of the damping hole 251 and the piston accumulator 320, the greater the extension stroke of the buffer piston 240, the greater the pressure in the rod chamber 242, and the oil in the buffer piston 240 and the return oil chamber 110 is decelerated and buffered. Finally, before the buffer piston 240 reaches the end of the stroke, the oil in the buffer piston 240 and the return oil chamber 110 is decelerated to 0, and then begins to move in the retraction direction. After multiple layers of rebound, the buffer piston 240 finally stabilizes in the equilibrium position; at this point, the buffering stage ends. The schematic diagram of the position of the buffer piston 240 and the impact piston 230 moving to the extreme position is shown in FIG. Figure 3 shown.

[0059] The preferred embodiment of the present invention also provides an impact test system, whose return oil pipe or high-speed switching valve group is connected to the return oil buffer device as any of the above items, so that in the impact test system of the present invention, the entire impact buffering process has obvious impact stage and buffering stage. The return oil resistance in the impact stage is small, and the instantaneous impact pressure in the impact stage decreases rapidly, which is not easy to cause damage to the cylinder assembly and the piston. In the buffering stage, the deceleration back pressure is obtained by relying on the oil pressure loss. The buffering effect is obvious and easy to control, which is suitable for the field of high-speed and large-flow return oil buffering of impact hydraulic systems.

[0060] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An oil return buffer device, characterized in that: include: Cylinder assembly, buffer piston (240), impact piston (230), overflow detection circuit, oil filling detection circuit (300) and air filling detection circuit (400); The cylinder assembly is in the shape of a hollow cylinder for connecting to an impact test system, and has a first inner cylinder cavity arranged along the axial direction, and a buffer cavity (262) connected to the first inner cylinder cavity through a damping hole (251), and the buffer cavity (262) is connected to an oil filling detection circuit (300) so as to perform oil filling and pressure detection on the buffer cavity (262) through the oil filling detection circuit (300); The buffer piston (240) is slidably disposed in the first inner cylinder cavity to separate the first inner cylinder cavity into a first side cavity and a second side cavity located on both sides thereof and not connected, and the second side cavity is connected to the buffer cavity (262) through a damping hole (251); The buffer piston (240) is in the shape of a hollow cylinder and has a second inner cylinder cavity arranged along the axial direction. The impact piston (230) is slidably arranged in the second inner cylinder cavity to separate the second inner cylinder cavity into an oil return cavity (110) and an air cavity (272) located on both sides thereof and not connected. The oil return cavity (110) is connected to the first side cavity and is used to communicate with the impact oil return (100) of the impact test system. The oil return cavity (110) is also connected to an overflow detection circuit to allow the lubricating oil in the oil return cavity (110) to overflow and to detect pressure. The air cavity (272) is connected to an inflation detection circuit (400) to inflate the air cavity (272), detect pressure, and discharge the gas in the air cavity (272) to the atmosphere through the inflation detection circuit (400).

2. The oil return buffer device according to claim 1, characterized in that: The oil return buffer device also includes a buffer piston rod (241) axially connected to the buffer piston (240), and the buffer piston rod (241) is located in the second side cavity so that the second side cavity forms a rod cavity (242); The cylinder assembly comprises a hollow cylinder (210), a first end cover (250) for sealing the second end of the cylinder (210), and a first end cover cylinder body (252) axially connected to the first end cover (250) for accommodating a buffer piston rod (241); the first end of the cylinder (210) is in communication with an oil return chamber (110); The buffer piston (240) is slidably disposed in the inner barrel cavity of the cylinder barrel (210), and the two are in sealing contact via a sealing ring. The buffer piston rod (241) passes through a rod cavity (242) along the axial direction and then extends into the first end cover cylinder (252), and the buffer piston rod (241) and the first end cover cylinder (252) are in sealing contact via a sealing ring.

3. The oil return buffer device according to claim 2, characterized in that: The first end cover cylinder (252) is in the shape of a hollow cylinder with two ends connected; The cylinder assembly further comprises a third end cover (270) for sealing the free end of the first end cover cylinder (252); the third end cover (270) is provided with an air hole (271) extending therethrough; the air hole (271) is connected to the inflation detection circuit (400); The buffer piston rod (241) is in the shape of a hollow cylinder with two connected ends, and the two ends of the buffer piston rod (241) are respectively connected to the air cavity (272) and the inner cylinder cavity of the first end cover cylinder (252), so that the air cavity (272) is connected to the inner cylinder cavity of the buffer piston rod (241) and the inner cylinder cavity of the first end cover cylinder (252) in sequence.

4. The oil return buffer device according to claim 3, characterized in that: The inflation detection circuit (400) comprises an air supply pipeline communicating with the air hole (271), and a second needle valve (410), an air cavity pressure sensor (420) and an electric ball valve (430) connected to the air supply pipeline.

5. The oil return buffer device according to claim 2, characterized in that: The cylinder assembly also includes a second end cover (260) sleeved on the outer circle of the first end cover barrel (252) and located outside the first end cover (250); the second end cover (260) is concavely arranged to enclose a buffer cavity (262) between the second end cover (260) and the first end cover (250); the second end cover (260) is also provided with a buffer oil port (261) penetrating and communicating with the buffer cavity (262); the buffer oil port (261) is connected to an oil filling detection circuit (300); The damping hole (251) is a multi-circle annular hole opened on the first end cover (250) and in the shape of a concentric ring, so that the rod cavity (242) and the buffer cavity (262) are connected through the multi-circle annular hole.

6. The oil return buffer device according to claim 2, characterized in that: The cylinder assembly also includes a second end cover (260) which is annular and sealingly sleeved on the outer circle of the cylinder (210); the second end cover (260) is concavely arranged to enclose a buffer cavity (262) between the second end cover (260) and the cylinder (210); the second end cover (260) is also provided with a buffer oil port (261) which is arranged through and communicates with the buffer cavity (262); the buffer oil port (261) is connected to an oil filling detection circuit (300); The damping holes (251) are a plurality of damping holes (251) groups which are sequentially opened on the cylinder barrel (210) along the axial direction, and each damping hole (251) group comprises a plurality of damping holes (251) which are sequentially spaced along the circumferential direction, so that the rod cavity (242) and the buffer cavity (262) are connected through the damping holes (251) group.

7. The oil return buffer device according to claim 6, characterized in that: The apertures of the damping holes (251) of the multi-circle damping hole (251) group gradually decrease along the damping sliding direction of the buffer piston (240).

8. The oil return buffer device according to any one of claims 5 or 6, characterized in that: The oil filling detection circuit (300) comprises an oil delivery pipeline connected to the buffer oil port (261), and a ball valve (330) and a buffer chamber pressure sensor (340) connected to the oil delivery pipeline.

9. The oil return buffer device according to claim 8, characterized in that: The oil filling detection circuit (300) also includes a piston accumulator (320) connected to the oil pipeline. The piston accumulator (320) is provided with a gas filling chamber and an oil filling chamber separated from each other. The gas filling chamber is also connected to an external inert gas source via a first needle valve (310), and the oil filling chamber is connected to the buffer oil port (261).

10. The oil return buffer device according to claim 2, characterized in that: The cylinder assembly also includes a piston cover (220) located in the first side cavity. The piston cover (220) is used to abut against the corresponding end of the buffer piston (240) along the axial direction, and the piston cover (220) partially extends into the oil return cavity (110) to abut against the impact piston (230) to prevent the impact piston (230) from sliding out of the buffer piston (240).

11. The oil return buffer device according to claim 2, characterized in that: The overflow detection circuit comprises an overflow pipeline connected to the oil return chamber (110), and an oil return chamber pressure sensor (120), an electromagnetic ball valve (130) and an overflow valve (140) which are sequentially connected to the overflow pipeline.

12. An impact test system, characterized in that: Its oil return pipe or high-speed switch valve group is connected to the oil return buffer device as described in any one of claims 1-11.

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