Unloading valve and combined valve type buffer cylinder

Abstract

The present invention relates to the field of hydraulic cylinders, and in particular to a relief valve and a combination valve type buffer cylinder, wherein the relief valve comprises a valve body, a valve core and a return spring, and is also provided with a damping hole and a relief groove; the combination valve comprises a relief valve and a throttle valve, and the throttle valve comprises a buffer plug and a buffer chamber; the piston rod assembly of the combination valve type buffer cylinder is installed in the cylinder body, and the cylinder body comprises a cylinder head flange, a cylinder bottom and a cylinder barrel, and the piston rod assembly comprises a guide sleeve, a piston and a piston rod; the combination valve is arranged on the cylinder; the technical scheme involved in the invention increases the unloading function of the oil inlet chamber, has an outstanding buffering effect, reduces the buffering pressure, and at the same time makes the system in an unloading state during the buffering stage, reduces the energy loss and heating of the system, avoids the pressure shock caused by the buffering to the system, improves the reliability of the system, and reduces the difficulty of performance matching and installation and debugging of the original buffer valve.

Description

Technical Field

[0001] The invention relates to the field of hydraulic cylinders and hydraulic valves, and in particular to an unloading valve and a combined valve type buffer cylinder. Background Art

[0002] The oil cylinders of engineering machinery are generally medium-high pressure heavy-duty oil cylinders, with high working pressure and high inertia of the reciprocating parts of the oil cylinder. Therefore, there is often a large mechanical collision impact at the end of the stroke of the oil cylinder piston's frequent reciprocating motion, which leads to the occurrence of failures. At the same time, it also brings a large hydraulic shock, causing hydraulic system failures. The current solution is generally to add a buffer mechanism to the oil cylinder, that is, to set a buffer chamber at the end of the oil cylinder stroke, and set a buffer plug on the piston rod. When the oil cylinder piston approaches the end of the stroke, the buffer plug enters the buffer chamber and blocks the oil return port to form a throttling effect, forcing the pressure of the oil cylinder return chamber to increase, and using the return oil back pressure to prevent and reduce the movement speed of the piston, reduce the mechanical collision at the end of the piston stroke, and achieve the buffering purpose of the oil cylinder (see patents: 201020114293.3; 201410332785.2; 201410560827.8).

[0003] The above technology reduces the mechanical collision strength of the cylinder piston to a certain extent and plays a certain buffering role, but there are still the following shortcomings: since the pressure in the oil inlet chamber of the cylinder is not unloaded during the buffering process, while the cylinder throttles the return oil chamber to prevent the movement of the piston, the oil inlet chamber at the other end of the piston continues to work to provide power to the piston. The system pressure will also increase with the sudden increase in the buffering pressure to form a system pressure shock, causing unnecessary power consumption and energy waste in the oil inlet chamber, increasing system heat and reducing the buffering effect.

[0004] Patents CN201610419750.1, CN202010751295.1 and CN202021559346.2 effectively solve the above-mentioned problems of the prior art by setting a buffer valve to control the throttling of the oil return chamber and the unloading of the oil inlet chamber of the oil cylinder. However, the throttling control is mainly completed by the buffer valve spool. A small amount of oil is isolated from the oil cylinder chamber as the output signal oil by a separately set signal device to control the movement of the valve spool and dynamically adjust the size of the throttling port and the unloading port of the buffer valve. However, due to the small amount of signal oil and the many and sensitive factors affecting the signal oil flow and pressure, it is difficult to control it to a relatively ideal state. It is easy to produce large pressure shock fluctuations, causing the valve spool to move up and down, making the stability of the throttling port worse. The fluctuations of the throttling port and the unloading port of the buffer valve will react on the signal oil of the control valve spool, thereby further affecting the steady-state performance of the buffer valve, thereby affecting the adjustment quality of the throttling port. At the same time, the anti-interference ability of the valve needs to be improved. During the normal operation of the oil cylinder, when the abnormal movement of the valve core caused by pressure fluctuation exceeds a certain amplitude and causes oil return throttling, the pressure difference generated by the throttling will further prompt the valve core to continue to move in an unexpected direction, thereby causing the buffer valve to malfunction and affect the normal use of the oil cylinder. In summary, the spring stiffness, buffer valve throttle port, unloading port, damping hole, and cross-sectional area of ​​the signal cavity are all factors that affect the dynamic characteristics and stability of the buffer valve. Reasonable matching is difficult, and the overadjustment of the valve core adjustment is not easy to control. Therefore, the adjustment and control of the buffer valve becomes very complicated, and there is still a lot of room for improvement in the buffer quality and stability; and because the valve core diameter will affect the flow of the main oil channel, a small diameter design cannot be adopted. Therefore, the valve core diameter and the valve structure are both large, complex, difficult to arrange, and high in cost, which need to be improved. Summary of the invention

[0005] The main purpose of the present invention is to provide a relief valve and a combined valve type buffer cylinder to solve the problems existing in the prior art.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A relief valve comprises a valve body, a valve core and a return spring. The valve body is provided with a valve hole. The valve core is mounted in the valve hole. A drive cavity of the valve core and a spring cavity of the valve core are formed at both ends of the valve hole. The return spring is arranged in the spring cavity. One end of the return spring is compressed and pressed against the bottom of the spring cavity, and the other end is compressed and pressed against one end of the valve core. Under the thrust of the return spring, the other end of the valve core is pressed against the bottom of the drive cavity. The valve core is provided with a relief groove. The valve body is provided with an oil passage I and an oil passage II which can be connected through the relief groove. The valve body is provided with an oil passage III connected to the drive cavity. The oil passage II is connected to the spring cavity. In a non-relief state, the relief groove is connected to the oil passage I, and is not connected to the oil passage II, the spring cavity and the drive cavity (11).

[0008] Furthermore, the valve body is also provided with an oil passage IV communicating with the spring chamber.

[0009] Furthermore, it also includes a damping hole, which is arranged on the valve core, on the guide sleeve, on the cylinder bottom or in the oil circuit, and the driving chamber and the spring chamber are connected through the damping hole.

[0010] Furthermore, the unloading groove includes an annular groove surrounding the surface of the valve core and / or an axial groove recessed along the surface of the valve core, and the axial groove is arranged along the circumferential direction of the valve core.

[0011] Furthermore, the unloading valve is integrated into a guide sleeve of the oil cylinder or integrated into a cylinder bottom of the oil cylinder.

[0012] Furthermore, the unloading valve is assembled on the guide sleeve, on the cylinder bottom or on the oil line.

[0013] Furthermore, the unloading valve is a cartridge valve.

[0014] Furthermore, the unloading valve also includes a valve sleeve, the valve core is fitted in the valve sleeve and is positioned in the valve body through the valve sleeve insertion, and an oil channel V is provided on the valve sleeve, and the oil channel V is used to cooperate with the unloading groove to realize the unloading function of the unloading valve.

[0015] A combination valve type buffer cylinder, the buffer cylinder includes a guide sleeve, the guide sleeve is slidably matched with a piston rod, the piston is fixedly connected to the piston rod, the piston divides the inner cavity of the cylinder body into two cylinder chambers, the buffer cylinder also includes a combination valve, the combination valve includes a group of throttle valves and a group of the above-mentioned unloading valves used in pair, the throttle valve includes a buffer plug and a buffer cavity, the buffer plug is arranged on the piston rod, the buffer cavity is arranged at the end of the cylinder body, the buffer cavity also serves as the inlet and outlet oil channel of the cylinder chamber at the cylinder end, connected to the spring cavity of the unloading valve, and the spring cavity is connected to the system oil circuit through the oil channel II; the driving cavity of the unloading valve is connected to the cylinder chamber at the buffer cavity end of the cylinder body through the oil channel III, and the unloading groove of the unloading valve is always connected to the other cylinder chamber of the cylinder through the oil channel I.

[0016] Furthermore, the spring chamber is also connected to the oil cylinder chamber at the buffer chamber end of the cylinder body through the oil passage IV.

[0017] Furthermore, it includes two sets of combined valves used in conjunction with each other to control the buffering at both ends of the oil cylinder respectively;

[0018] Furthermore, the two groups of unloading valves of the two groups of combined valves are separately arranged.

[0019] Furthermore, the two groups of unloading valves of the two combined valves are integrated together, and the spring chamber of the valve core of each group of unloading valves is respectively communicated with the unloading groove of the other group of unloading valves.

[0020] Furthermore, a one-way valve is also included.

[0021] Furthermore, the one-way valve is arranged on the throttle valve, and the one-way valve includes an oil-filled gap formed between the inner hole of the buffer plug and the mating surface of the piston rod, an end face oil groove arranged on the end face of the buffer plug facing the piston end, and a one-way valve port formed by the corresponding shoulder surfaces on the buffer plug and the piston rod.

[0022] Furthermore, the one-way valve is arranged on the valve core, the one-way valve comprises a one-way valve core and a one-way valve spring (22), the damping hole of the unloading valve is arranged on the one-way valve core, a central oil channel is arranged on the valve core, the one-way valve core is installed at the mouth of the central oil channel of the valve core, and the one-way valve spring is compressed and installed at the bottom of the driving chamber; under normal conditions, the one-way valve core is pressed against the mouth of the central oil channel under the thrust of the one-way valve spring, and the one-way valve port is in a closed state.

[0023] Furthermore, a throttling groove is formed on the buffer plug, and the throttling groove is a plane groove obliquely cut along the surface of the valve core or a longitudinal groove cut longitudinally.

[0024] The present invention has the following beneficial effects:

[0025] (1) The unloading valve unloads the oil inlet chamber of the oil cylinder, reduces the pressure in the oil inlet chamber, reduces the power of the piston, effectively avoids unnecessary power consumption and system heating, reduces the pressure shock of the system, protects the hydraulic system, and improves the buffering effect of the oil cylinder;

[0026] (2) The combination valve sets the throttling function and the unloading function separately, and controls the unloading valve through the throttling valve. The throttling valve is responsible for throttling the oil return chamber of the cylinder during the buffering process and at the same time uses the throttling pressure difference to control the unloading valve.

[0027] (3) Compared with the traditional hydraulic cylinder, the hydraulic buffer cylinder has a more prominent buffering effect due to the added unloading function of the oil inlet chamber, that is, it reduces the buffering pressure and puts the system in an unloading state during the buffering stage, reducing the energy loss and heating of the system, avoiding the pressure shock caused by the buffering to the system, and improving the reliability of the system.

[0028] (4) Compared with patents CN201610419750.1, CN202010751295.1 and CN202021559346.2 which also have unloading functions, the present invention changes the buffer device of the above patents into a combined valve form in which a throttle valve and an unloading valve work together, so that the buffer control is more stable and simple, the buffer quality is further improved, and the structure is simplified. The unloading valve core does not require a large oil flow rate, so a small valve core structure design can be achieved, the volume is reduced, the control requirements are also reduced, the control is simple, the valve performance is improved, the reliability is high, and the valve leakage is small. The present invention transforms the function of the signal chamber of the aforementioned patent into a throttling function, and the signal chamber is transformed into a buffer chamber, which also serves as the hydraulic oil inlet and outlet channel of the oil cylinder chamber; the signal plug is transformed into a buffer plug, and throttling adjustment is achieved through the cooperation of the buffer plug and the buffer chamber, which changes the original method of adjusting the throttling port by controlling the movement of the valve core with signal oil, thereby avoiding large fluctuations in the buffer pressure caused by the movement of the valve core; at the same time, the control oil circuit and control method of the valve core are changed, and the pressure oil and buffer pressure of the return oil chamber are directly used to control the movement of the valve core, so that the generation method of the control signal oil, the source of the oil volume, the amount of oil, the control sensitivity and the control requirements are all changed, thereby improving the control quality, eliminating the phenomenon of malfunction of the buffer valve core that may occur in the normal operation of the oil cylinder in the original technology, and allowing the pressure oil in the oil inlet chamber of the oil cylinder to be quickly unloaded through the valve core unloading groove, thereby achieving the purpose of unloading buffering of the oil inlet chamber of the oil cylinder.

[0029] (5) The present invention comprehensively utilizes the advantages of the above-mentioned patents and eliminates the shortcomings of the prior art through structural improvements, thereby making its structural performance more superior and the buffering quality further improved. At the same time, it reduces the difficulty of performance matching and installation and debugging of the original buffer valve, makes the processing technology simpler, reduces the manufacturing difficulty, and improves the reliability of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 Schematic diagram of the structure principle of embodiment 1 of the present invention, the unloading valve is arranged inside the guide sleeve, and the piston moves from the bottom end of the cylinder to the end of the guide sleeve in the figure;

[0031] Figure 2 yes Figure 1 A magnified image of point A;

[0032] Figure 3 This is a schematic diagram of the structural principle of the oil cylinder starting to buffer when the piston moves to a position close to the end of the stroke in Example 1;

[0033] Figure 4 yes Figure 3 A magnified view of point B;

[0034] Figure 5 This is one of the schematic diagrams of the structural principle of embodiment 2, in which the unloading valve is arranged at the bottom of the cylinder;

[0035] Figure 6 This is the second schematic diagram of the structural principle of embodiment 2, in which the unloading valve is arranged at the bottom of the cylinder;

[0036] Figure 7 This is a schematic diagram of the structural principle of Embodiment 3, wherein unloading valves are provided in the guide sleeve and the cylinder bottom;

[0037] Figure 8 This is one of the structural schematic diagrams of the circular sleeve-shaped buffer plug in Example 4;

[0038] Fig. 9 This is the second structural schematic diagram of the cylindrical buffer plug in Example 4;

[0039] Fig.10 yes Figure 3 After the cylinder buffering is completed, when the piston moves in the reverse direction, the hydraulic oil is quickly filled into the corresponding cylinder chamber through the one-way valve;

[0040] Fig.11 yes Fig.10 The enlarged view of point C is the setting method of the one-way valve in Example 4;

[0041] Fig.12 yes Fig.10 The enlarged view of point C is the setting method of the one-way valve in Example 5;

[0042] Fig.13 It is one of the ways to set up the unloading tank;

[0043] Fig.14 This is the second way to set up the unloading chute;

[0044] Fig.15 This is the third way to set up the unloading trough;

[0045] Fig.16 is a schematic diagram of the structure in which the unloading valve of Embodiment 6 is assembled outside the cylinder body;

[0046] Fig.17 It is a schematic diagram of the action principle of the present invention, illustrating the structure of a one-way buffer cylinder;

[0047] Fig.18 This is one of the schematic diagrams of the action principle of the present invention, illustrating the structure of a bidirectional buffer cylinder;

[0048] Fig.19 yes Fig.18 Schematic diagram of the valve core action principle when the guide sleeve end is buffered;

[0049] Fig. 20 yes Fig.18 Schematic diagram of the valve core action principle when the cylinder bottom end is buffered;

[0050] Fig.21 One of the structural diagrams of Embodiment 10;

[0051] Fig. 22 The second structural diagram of embodiment 10;

[0052] Fig.23 One of the structural schematic diagrams of Example 11;

[0053] Fig.24 The second structural diagram of Example 11;

[0054] Among them, 1. guide sleeve; 2. cylinder head flange; 3. cylinder barrel; 4. buffer plug; 4-1, throttle groove; 5. piston; 6. piston rod; 7. cylinder bottom; 8. cylinder chamber; 9. buffer chamber; 10. valve core; 11. drive chamber; 12. valve hole; 13. unloading groove; 14. spring chamber; 15. damping hole; 16. return spring; 17. throttle port; 18. end face oil groove; 19. oil filling gap; 20. one-way valve port; 21. one-way valve core; 22. one-way valve spring; 23. valve sleeve; 24. oil channel I; 25: oil channel II; 26: oil channel III; 27: oil channel IV; 28: oil channel V; X, unloading valve. DETAILED DESCRIPTION

[0055] The present invention will be further described below in conjunction with the accompanying drawings.

[0056] Embodiment 1:

[0057] like Figure 1-4 As shown, a relief valve is integrated on the guide sleeve of the oil cylinder and used in conjunction with the oil cylinder to realize the relief buffer function of the oil cylinder, comprising a valve body, a valve core 10 and a return spring 16. The valve body is provided with a valve hole 12, and the valve core is installed in the valve hole in conjunction with each other, forming a driving chamber 11 of the valve core and a spring chamber 14 of the valve core at both ends of the valve hole, respectively. The return spring is arranged in the spring chamber, one end of which is compressed and pressed against the bottom of the spring chamber, and the other end is compressed and pressed against one end of the valve core. Under the thrust of the return spring, the valve core causes the other end of the valve core to move. The end is pressed against the bottom of the drive chamber; a damping hole 15 and a unloading groove 13 are also provided on the valve core, the drive chamber and the spring chamber of the valve hole are connected through the damping hole, the drive chamber is also connected with the corresponding cylinder chamber 8 through the oil passage III 26, the cylinder chamber can also be connected with the corresponding spring chamber through the oil passage IV 27, the spring chamber is connected to the system oil circuit through the oil passage II 25; the unloading groove of the corresponding valve core is connected with the oil passage of another cylinder chamber; the unloading valve is also provided with an oil passage I 24, and the oil passage I 24 and the oil passage II 25 can be connected through the unloading groove.

[0058] When the valve core is maintained at the bottom position of the driving chamber under the thrust of the return spring, the unloading groove of the unloading valve is in a state of being completely closed by the valve hole, thereby cutting off the connection between the unloading groove and other chambers of the unloading valve, ensuring that the normal inflow and outflow of oil in the cylinder chamber at one end of the cylinder bottom in the non-buffered working state is not affected by the unloading valve, thereby maintaining the normal working state of the cylinder.

[0059] The combination valve includes a throttle valve and an unloading valve. The throttle valve includes a buffer plug and a buffer chamber. The buffer plug is arranged on the piston rod, and the buffer chamber is arranged on the guide sleeve. The buffer chamber also serves as an inlet and outlet channel for the hydraulic oil of the corresponding cylinder chamber and is connected with the spring chamber of the unloading valve. The spring chamber is further connected to the system oil circuit through oil channel II; accordingly, the driving chamber of the unloading valve is connected with the corresponding cylinder chamber, and the unloading groove of the unloading valve is always connected with the other cylinder chamber of the cylinder.

[0060] A combination valve type buffer oil cylinder, only a combination valve is arranged in the oil cylinder chamber at one end of the guide sleeve, the combination valve includes a throttle valve and a relief valve, the throttle valve is arranged in the oil cylinder chamber at one end of the oil cylinder guide sleeve, and the relief valve is integrated on the guide sleeve. The buffer plug 4 of the throttle valve is arranged on the piston rod, and the buffer chamber is arranged on the guide sleeve, so that the oil cylinder can be buffered at one end of the guide sleeve; the main components of the oil cylinder include a cylinder body, a piston 5, and a piston rod 6. The cylinder body includes a guide sleeve 1, a cylinder head flange 2, a cylinder bottom 7 and a cylinder barrel 3. The cylinder head flange and the cylinder bottom are respectively fixed at both ends of the cylinder barrel, the guide sleeve is fixed on the cylinder head flange, the piston is fixedly connected to the piston rod and slidably fits in the cylinder barrel, the guide sleeve slidably fits on the piston rod and restricts the piston in the cylinder body, and the piston divides the inner cavity of the cylinder body into two oil cylinder chambers, one located at one end of the guide sleeve, and the other located at one end of the cylinder bottom, which serve as the oil inlet chamber and the oil return chamber of the oil cylinder respectively.

[0061] When the valve core is maintained at the bottom of the driving chamber of the corresponding valve hole under the action of the return spring, the unloading groove of the valve core is in a state of being closed by the valve hole; when the buffer plug moves to the bottom of the oil return chamber with the piston, the buffer plug enters the corresponding buffer chamber, and forms a throttle port 17 by blocking the oil return channel of the oil return chamber. The hydraulic oil in the oil return chamber is forced to flow back to the oil tank from the throttle port and the damping hole of the unloading valve, which causes the pressure of the oil return chamber to increase, prevents the piston from moving, and achieves the purpose of buffering the throttling back pressure of the oil return chamber; at this time, the pressure of the unloading valve core driving chamber connected to the oil return chamber increases with the increase of the oil return chamber pressure, and the spring chamber at the other end of the unloading valve core is in a low-pressure oil return state at this time, thereby generating a pressure difference between the driving chamber and the spring chamber at both ends of the unloading valve core, driving the valve core to overcome the resistance of the return spring and move to the spring chamber in a low-pressure state, so that the unloading groove of the valve core is connected with the spring chamber, causing the high-pressure oil in the oil inlet chamber to be unloaded through the unloading groove and the spring chamber return oil, thereby achieving the purpose of unloading buffering of the oil inlet chamber.

[0062] The working principle of the combined valve type buffer cylinder is: Figure 1As shown in the figure, when the oil chamber on one side of the cylinder bottom is used as the oil inlet chamber to enter the high-pressure oil, the piston drives the buffer plug to move toward one end of the guide sleeve under the push of the high-pressure oil (as shown in the figure). Figure 1 At the same time, the oil cylinder chamber at one end of the guide sleeve serves as the oil return chamber, and the oil in the chamber flows back to the oil tank at low pressure (as shown by the arrow). Figure 2 Further, when the buffer plug moves with the piston to the end of the stroke (as shown in Figure 3 As shown), the buffer plug begins to enter the buffer cavity to form a throttle port 17 (as shown Figure 4 The oil return passage of the oil return chamber is blocked, and the hydraulic oil in the oil return chamber is forced to flow back to the oil tank from the throttle port and the damping hole of the unloading valve, thereby causing the pressure of the oil return chamber to increase, and the effect of the oil return back pressure is generated to prevent the movement of the piston, reduce the movement speed of the piston, and realize the buffering function of the throttling back pressure of the oil return chamber; at the same time, the pressure at one end of the valve core driving chamber connected to the oil return chamber will increase with the increase of the pressure in the oil return chamber, while the spring chamber at the other end of the valve core is still in a low-pressure oil return state because it is connected to the oil tank, so that the pressure at one end of the valve core driving chamber is higher than the pressure at one end of the valve core spring chamber, and then the valve core is driven to overcome the resistance of the return spring and slide to the end of the spring chamber in a low-pressure state, so that the valve core unloading groove gradually moves toward the valve core spring chamber and connects with it, so that the pressure oil in the oil inlet chamber of the cylinder (that is, the cylinder chamber at one end of the cylinder bottom) which is in a high-pressure oil inlet state at this moment can be connected with the valve core spring chamber through the valve core unloading groove and unloaded (as shown in the figure). Figure 4 As shown), the pressure of the oil inlet chamber is reduced, the driving force of the oil inlet chamber on the piston is reduced, and the speed of the piston movement is reduced, thereby achieving the purpose of the present invention: the efficient buffering of the oil cylinder is achieved through the dual effects of throttling the back pressure of the oil return chamber and simultaneously adding the high pressure unloading of the oil inlet chamber. Further, when the piston moves to the end of the stroke and stops moving, the buffering ends, the high pressure driving force at one end of the valve core driving chamber disappears, and the valve core returns to the bottom position of the driving chamber under the thrust of the return spring, and the valve core unloading groove is blocked by the valve hole (as shown in FIG. Figure 2 As shown), the unloading channel is closed and the cylinder returns to normal working state.

[0063] Embodiment 2:

[0064] like Figure 5 , Figure 6 As shown, a combination valve type buffer oil cylinder has a combination valve only arranged in the oil cylinder chamber at one end of the cylinder bottom. The combination valve is integrated on the cylinder bottom, so as to realize buffering of the oil cylinder at one end of the cylinder bottom. Figure 5 and Figure 6 The structure is similar, only the position of the unloading valve is different. Compared with Example 1, the main difference is that the valve hole of the unloading valve and the buffer cavity of the throttle valve are both arranged on the bottom of the cylinder, and the buffer plug of the throttle valve is arranged at the center of the bottom of the piston rod. Its working principle is similar to that of Example 1 and will not be repeated here.

[0065] Embodiment 3:

[0066] like Figure 7 As shown, a combination valve type buffer oil cylinder is provided with combination valves at both ends of the oil cylinder, which can realize buffering when the piston at either end of the oil cylinder approaches the end of the oil cylinder stroke. This embodiment is a composite structure of embodiment 1 and embodiment 2, which can realize the bidirectional buffering function of the oil cylinder. During the operation of the oil cylinder, when the piston approaches the end of the stroke of one end of the oil cylinder, only the combination valve provided at the end is activated to play the buffering function, and its working principle is similar to the above, which will not be repeated here.

[0067] Embodiment 4:

[0068] like Figure 8 , Fig. 9 As shown, the structure of the buffer plug can be set to different structural forms according to needs. Figure 8 The circular sleeve structure is shown as an example. Fig. 9 The cylindrical structure is shown in the example; the shape of the throttling groove can also be set to different structures as needed. Figure 8 and Fig. 9 The throttling groove 4-1 in the example is a planar groove structure obliquely cut on the surface of the buffer plug. Other longitudinal groove structures such as triangular grooves, rectangular grooves, arc grooves, etc. can also be cut longitudinally on the surface of the buffer plug. Figure 13-15 The setting methods of several valve core unloading grooves shown are similar and will not be listed here in detail.

[0069] Embodiment 5:

[0070] The form of the valve core unloading groove can also be set to different structures according to needs. Figure 2 The exemplary unloading groove is an annular groove cut on the valve core surface around the valve core axis. According to needs, the unloading groove can also be set as a longitudinal groove structure in other forms such as a plane groove, a triangular groove, a rectangular groove, an arc groove, etc. cut along the surface, or can be set as a composite structure of an annular groove and a longitudinal groove. Fig.13 Two ring groove structures are shown as examples. Fig.14 Two longitudinal groove structures are illustrated, and the longitudinal grooves are evenly distributed on the valve core surface along the circumferential direction; Fig.15 It is a combination of annular grooves and longitudinal grooves, which will not be enumerated here.

[0071] Embodiment 6:

[0072] like Fig.10 As shown, the combination valve of the combination valve type buffer cylinder involved in the invention is provided with a one-way valve function. When the piston moves in the opposite direction at the end of buffering, the hydraulic oil can be quickly filled into the corresponding cylinder chamber through the one-way valve.

[0073] Fig.11As shown, the one-way valve is arranged on the throttle valve of the combination valve, and the buffer plug of the throttle valve is coaxially assembled on the piston rod, and an oil-filled gap 19 is formed between its inner hole and the matching surface of the piston rod. An end surface oil groove 18 is also arranged on the end surface of the buffer plug facing the piston end. When the end surface of the buffer plug is pressed against the end surface of the piston, the oil-filled gap of the buffer plug can still be connected with the corresponding cylinder chamber through the end surface oil groove; the buffer plug and the piston rod are correspondingly provided with mutually matching shoulder surfaces to form a one-way valve port 20. When the shoulder surface of the buffer plug is pressed against the shoulder surface of the piston rod, the oil path of the oil-filled gap is cut off, and the one-way valve port 20 is in a closed state, as shown in FIG. Figure 4 When buffering starts, the buffer plug enters the buffer chamber, blocking the oil return passage of the oil return chamber. The pressure in the oil return chamber increases, and the buffer plug shoulder surface is pressed against the piston rod shoulder surface under the pressure of the oil return chamber. The one-way valve port 20 is closed, thereby cutting off the passage of the hydraulic oil in the oil return chamber through the oil groove 18 on the end face of the buffer plug and the oil filling gap 19 into the buffer chamber and the spring chamber. The pressure oil in the oil return chamber is forced to enter the buffer chamber and the spring chamber through the throttle port (such as Figure 4 As shown); when the buffer ends and the piston moves in the opposite direction, Fig.11 As shown, the buffer plug begins to move toward one end of the piston under the impact of the incoming high-pressure oil and is pressed tightly against the piston end face. At this time, the one-way valve port 20 opens, and the inlet pressure oil can be injected into the cylinder chamber through the spring chamber and the one-way valve port 20, the oil filling gap 19, and the end face oil groove 18, thereby realizing rapid oil filling.

[0074] Embodiment 7:

[0075] Fig.12 Another arrangement of a combination valve check valve is illustrated. This embodiment is similar to embodiment 6, except that the check valve is arranged on the valve core of the unloading valve, including a check valve core 21 and a check valve spring 22, and the front end of the check valve core has a sealing surface inclined outward. Accordingly, the damping hole 15 is arranged on the check valve core, the check valve core is installed at the central oil passage opening of the unloading valve core, the check valve spring is compressed and installed between one end of the check valve core and the bottom of the driving chamber, the check valve core is pressed against the opening of the central oil passage of the valve core under the thrust of the check valve spring, and the check valve opening is closed; when the buffer ends and the piston moves in the reverse direction, the buffer chamber is blocked by the buffer plug at this time, and the inlet pressure oil cannot pass through the buffer chamber to enter the oil cylinder chamber after entering the spring chamber, and can only push the check valve core 21 through the central oil passage of the unloading valve core, thereby opening the check valve opening, and the inlet pressure oil can quickly enter the oil cylinder chamber through the check valve, realizing rapid oil filling, such as Fig.12 As shown in the figure, the arrows and thin solid lines show the flow path of the imported oil through the one-way valve; further, when the buffer plug is moved out of the buffer cavity, the imported pressure oil can smoothly pass through the buffer cavity into the cylinder chamber. At this time, the one-way valve core is pressed against the mouth of the central oil channel of the valve core under the thrust of the one-way valve spring, and the one-way valve port is closed ( Fig.12not shown).

[0076] The one-way valve can be flexibly arranged according to needs and can be arranged at different positions. The one-way valve core can also be arranged as other equivalent structures, which are not listed here one by one.

[0077] Embodiment 8:

[0078] The position of the unloading valve can be flexibly set according to needs. Fig.17 This is a working principle diagram of the unloading valve of the one-way buffer cylinder (the buffer at the guide sleeve end is taken as an example in the figure). The unloading valve can be externally installed on the guide sleeve, cylinder bottom or pipeline, or it can be integrated into the cylinder body, such as built into the guide sleeve, cylinder bottom or cylinder head flange and other components. Fig.16 for Fig.17 Some specific embodiments of the present invention illustrate three structural forms of external unloading valves. Fig.16 The unloading valve X of Ⅰ is a separate component independent of the cylinder body and is fixed on the guide sleeve in an assembled form. It is a single-acting unloading valve. When the oil cylinder is throttled and buffered at one end of the guide sleeve, the oil inlet chamber at one end of the cylinder bottom can be unloaded through the external unloading valve; Fig.16 The unloading valve of Ⅱ is fixed on the bottom of the cylinder. Fig.16 The unloading valve of Ⅲ is installed on the oil cylinder pipeline. Fig.17 for Fig.16 The schematic diagram of the structural principle of the piston shows the flow direction and path of the hydraulic oil when the piston moves toward the guide sleeve end. The buffering principle is similar to the above and will not be repeated here.

[0079] Embodiment 9:

[0080] Figure 18-20 The schematic diagram of the principle of integrating the unloading valve at the guide sleeve end and the unloading valve at the bottom end of the cylinder is illustrated. It has two valve cores and is a double-acting unloading valve that can control the buffering unloading at the guide sleeve end and the bottom end of the cylinder respectively, thereby realizing two-way unloading buffering of the cylinder. Fig.18 It is the normal flow state of the oil when the piston moves toward the guide sleeve end.

[0081] Fig.19 for Fig.18 The schematic diagram shows the principle that the piston moves to near the end of the stroke and the buffer plug enters the buffer chamber to start buffering. At this time, the buffer plug enters the buffer chamber to form oil return throttling, the pressure in the oil return chamber increases, and the pressure oil in the oil return chamber enters the driving chamber of the corresponding valve core to drive the valve core to move to one end of the spring chamber, so that the valve core unloading groove is connected with the spring chamber, and the pressure oil in the oil inlet chamber can be connected with the oil tank through the valve core unloading groove and the spring chamber to start unloading. The buffering principle is similar to the above and will not be repeated here.

[0082] Fig. 20 for Fig.18Schematic diagram of the buffering principle of the piston moving in the opposite direction to the bottom of the cylinder after the buffering is completed, and the valve core corresponding to the bottom of the cylinder starts to move to achieve the unloading buffering of the bottom of the cylinder. Figure 7 Similar, no repetition here.

[0083] Embodiment 10:

[0084] The damping hole 15 can be arranged in a flexible manner according to the needs. It can be arranged on the valve core of the unloading valve, as shown in the above embodiment; it can also be arranged on other parts, such as the guide sleeve, the cylinder bottom, or other positions in the oil circuit. Figure 21-22 For example, Fig.21 Yes Fig.17 The damping hole is moved from the valve core position to other positions in the oil circuit, and its working principle remains unchanged; Fig. 22 Yes Figure 4 The damping hole is moved from the valve core position to the guide sleeve. The damping hole can directly borrow the buffer throttle hole setting method of the existing buffer oil cylinder, which has the same effect and will not be repeated here.

[0085] Embodiment 11:

[0086] The unloading valve can also be in the form of a cartridge valve, inserted into a component of the oil cylinder or an oil circuit block of the oil cylinder pipeline. Figure 23-24 The structural principle of the cartridge valve type unloading valve is illustrated, a valve sleeve is added, the valve core is matched in the valve sleeve, and the valve core is positioned and assembled on the oil cylinder through the valve sleeve. The valve sleeve is also provided with an oil passage V28, and the unloading function of the unloading valve is realized through the cooperation of the oil passage V and the unloading groove of the valve core. Figure 23-24 Taking the buffer of the cylinder at one end of the guide sleeve as an example, the working state and action principle of the cartridge valve type unloading valve of the cylinder in normal working state and buffer state are respectively demonstrated. Its working mechanism is similar to the above and will not be repeated here.

[0087] Embodiments 1-11 are only preferred structural examples. Figure 1-24 Based on the guidance and the introduction of the above embodiments 1-11, more embodiments can be varied, which will not be listed here in detail.

[0088] It should be pointed out that the above are only preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited to this. Obviously, various changes can be made according to actual needs, such as: changes in the setting form of the combination valve, the combination mode and installation mode of the unloading valve, changes in the installation position, changes in the valve core and valve hole structure, changes in the setting mode of the buffer cavity and the buffer plug throttling groove, changes in the oil port and oil channel of the unloading valve (position, direction, shape, form, etc.), changes in the shape and position and number of the valve core unloading groove or the valve hole oil cavity, changes in the structural form of the oil cylinder, changes in the structural form of the one-way valve, etc.; the setting form of the return spring and the one-way valve spring can also be set to other structures as needed, as long as the return function of the valve core is met. Any technician familiar with the field can make equivalent replacements or changes according to the principle diagram, implementation plan and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered within the protection scope of the present invention.

Claims

1. A relief valve, comprising a valve body, a valve core (10) and a return spring (16), wherein the valve body is provided with a valve hole (12). Features: The valve core (10) is installed in the valve hole (12), and a driving chamber (11) of the valve core (10) and a spring chamber (14) of the valve core (10) are formed at both ends of the valve hole (12). A return spring (16) is arranged in the spring chamber (14), one end of which is compressed and pressed against the bottom of the spring chamber (14), and the other end of which is compressed and pressed against one end of the valve core (10). Under the thrust of the return spring (16), the other end of the valve core (10) is pressed against the bottom of the driving chamber (11); the valve core (10) is provided with a relief spring. A load groove (13) is formed on the valve body, an oil passage I (24) and an oil passage II (25) which can be communicated through the load groove (13), an oil passage III (26) which is communicated with the drive chamber (11) is formed on the valve body, and the oil passage II is communicated with the spring chamber (14); in a non-load-removing state, the load groove (13) is communicated with the oil passage I (24), and is not communicated with the oil passage II (25), the spring chamber (14) and the drive chamber (11); the drive chamber (11) and the spring chamber (14) are communicated through the damping hole (15); The invention also comprises a one-way valve, wherein the one-way valve is arranged on the valve core, the one-way valve comprises a one-way valve core (21) and a one-way valve spring (22), the damping hole (15) of the unloading valve is arranged on the one-way valve core (21), a central oil passage is arranged on the valve core (10), the one-way valve core (21) is installed at the mouth of the central oil passage of the valve core (10), and the one-way valve spring (22) is compressed and installed at the bottom of the driving chamber (11); under normal conditions, the one-way valve core (21) is pressed against the mouth of the central oil passage under the thrust of the one-way valve spring (22), and the one-way valve port (20) is in a closed state.

2. The unloading valve according to claim 1, Features: The valve body is also provided with an oil passage IV (27) communicating with the spring chamber (14).

3. The unloading valve according to claim 1 or 2, Features: The unloading groove (13) comprises an annular groove surrounding the surface of the valve core and / or an axial groove recessed along the surface of the valve core, wherein the axial groove is arranged along the circumferential direction of the valve core (10).

4. The unloading valve according to claim 1 or 2, Features: The unloading valve is integrated on the guide sleeve of the oil cylinder or on the cylinder bottom of the oil cylinder.

5. The unloading valve according to claim 1 or 2, Features: The unloading valve is assembled on the guide sleeve or the cylinder bottom.

6. A combined valve type buffer cylinder, the buffer cylinder comprising a guide sleeve (1), the guide sleeve (1) and a piston rod (6) being slidably matched, a piston (5) being fixedly connected to the piston rod (6), the piston (5) dividing the inner cavity of the cylinder body into two cylinder chambers (8), Features: The buffer oil cylinder also includes a combination valve, which includes a group of throttle valves and a group of unloading valves as described in any one of claims 1 to 5 for use in pairs, the throttle valve includes a buffer plug (4) and a buffer chamber (9), the buffer plug (4) is arranged on the piston rod (6), the buffer chamber (9) is arranged at the end of the cylinder body, the buffer chamber (9) also serves as the inlet and outlet oil channel of the cylinder chamber (8) at the cylinder end and is connected to the spring chamber (14) of the unloading valve, and the spring chamber (14) is connected to the system oil circuit through the oil channel II (25); the driving chamber (11) of the unloading valve is connected to the cylinder chamber (8) at the buffer chamber end of the cylinder body through the oil channel III (26), and the unloading groove (13) of the unloading valve is always connected to the other cylinder chamber (8) of the oil cylinder through the oil channel I (24).

7. The combined valve type buffer cylinder according to claim 6, Features: The spring chamber (14) is also connected to the oil cylinder chamber (8) at the cylinder body buffer chamber end through the oil passage IV (27).

8. The combined valve type buffer cylinder according to claim 6 or 7, Features: The utility model comprises two groups of combined valves used in coordination to respectively control the buffering at both ends of the oil cylinder.

9. The combined valve type buffer cylinder according to claim 8, Features: The two groups of unloading valves of the two groups of combined valves are separately arranged.

10. The combined valve type buffer cylinder according to claim 8, Features: The two groups of unloading valves of the two combined valves are integrated together, and the spring chamber (14) of the valve core (10) of each group of unloading valves is respectively communicated with the unloading groove (13) of the other group of unloading valves.

11. The combined valve type buffer cylinder according to any one of claims 6, 7, 9 and 10, Features: A throttling groove (4-1) is formed on the buffer plug (4), and the throttling groove (4-1) is a plane groove obliquely cut along the surface of the valve core (10) or a longitudinal groove cut longitudinally.

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