Secondary buffering overflow valve and using method thereof

Abstract

The invention provides a two-stage buffering overflow valve and a using method thereof. The two-stage buffering overflow valve comprises a valve sleeve. A valve cavity is formed in the valve sleeve; a buffer valve seat and a valve core are axially arranged in the valve cavity in a sliding manner; a first buffer chamber and a valve seat oil duct are arranged in the buffer valve seat; the end of the valve rod is connected into the first buffer chamber in a nested mode, and the valve seat oil channel penetrates through the buffer valve seat. A second buffering cavity communicated with the valve seat oil duct is formed between the buffering valve sleeve and the pressure adjusting plug, and a first gasket and a second gasket are slidably connected to the buffering valve seat in a sleeving mode; the valve rod is slidably sleeved with a first elastic piece and a second elastic piece. The first gasket can abut against the pressure adjusting plug, and the other side of the first gasket is connected with the conical end of the valve element through a first elastic piece. One side of the second gasket can abut against the buffer valve seat, and the other side of the second gasket can abut against the first gasket and is connected with the conical end of the valve element through a second elastic piece. According to the invention, the rotational inertia of the travel motor can be fully absorbed under the low-speed and small-load working condition, so that the problems of starting impact and stopping impact of the travel motor under the full working condition are solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of construction machinery, and particularly relates to a two-stage buffer overflow valve and a using method thereof. Background Art

[0002] In the complex operating environment of construction machinery excavators, the walking hydraulic system often needs to be frequently started and stopped. However, due to the large overall mass of the excavator and obvious inertial effects, the pressure of the hydraulic system rises sharply at the moment of starting and stopping, generating strong hydraulic shocks. Such shocks not only affect the operating smoothness of the excavator and the driving experience, but also cause additional wear to various components of the hydraulic system, thereby shortening the service life of the excavator. This requires a buffer overflow valve for hydraulic buffering. The buffer overflow valve, by cleverly combining pressure control and buffering technologies, significantly improves the operating stability of hydraulic equipment while ensuring system safety, and is an indispensable key component in high-end equipment manufacturing.

[0003] However, in the prior art, there are still many problems with buffer overflow valves: Such as Figure 4 shown, the existing buffer overflow valves (such as Figures 2-3 the Chinese patents CN202182080U and CN118548266A shown) achieve two-stage buffering through a buffer piston and a pressure regulating spring, and are divided into three stages during the debugging of pressure shocks. However, during the absorption of rotational inertia by the buffer piston in the second stage, the pressure does not change throughout the process, which limits the buffering performance of the overflow valve under different impact pressure conditions. Specifically, if the design value of the primary buffer pressure (the pressure in the second stage) is relatively high, in the face of a large instantaneous pressure shock (the whole machine running at high speed with heavy load) higher than this value, the overflow valve can effectively trigger the primary buffer mechanism and the buffering effect is good; however, when the instantaneous shock is lower than this design value, the buffering effect is greatly reduced because the shock still has a certain intensity at this time, but the buffer mechanism fails to intervene, resulting in a poor buffering effect. On the contrary, if the design value of the primary buffer pressure is low, although it can provide buffering for a small instantaneous shock (but still higher than this value), in the face of a larger instantaneous shock, although the primary buffer can be activated, due to the small buffer pressure and the reduced buffer time, the inertia cannot be fully absorbed before reaching the preset pressure value, resulting in a poor buffering effect.

[0004] In addition, for a specific excavator, the overflow pressure of the travel motor is usually set to a fixed value. However, during the impact debugging of the travel motor, most of the existing overflow valves adjust the initial compression amount of the spring by adjusting the plug or gasket to achieve the regulation of the primary pressure. Since the buffer distance does not change, this will cause the final compression amount of the spring to change, affecting the set pressure value of the travel motor overflow valve, increasing the debugging difficulty of the overflow valve and even causing the travel motor to fail to reach the working pressure value.

[0005] In addition, the existing technology uses a single spring for pressure regulation design, with a single spring stiffness, making it difficult to meet the diverse pressure regulation requirements, greatly limiting the adjustability of the pressure regulation range. At the same time, to meet specific pressure regulation requirements, the form of the spring combined with the buffer block often occupies more space, which is not conducive to the compact design of parts. Summary of the Invention

[0006] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a two-stage buffer overflow valve and its usage method, ensuring that the rotational inertia can be fully absorbed under low-speed and small-load conditions of the travel motor, thereby improving the starting impact and stopping impact problems of the travel motor under all working conditions.

[0007] To achieve the above object / To solve the above technical problems, the present invention is implemented by the following technical solutions: In the first aspect, the present invention provides a two-stage buffer overflow valve, including a valve sleeve; a valve cavity is arranged inside the valve sleeve; a buffer valve seat and a valve core are axially slidably arranged inside the valve cavity; The valve core includes a conical end and a valve stem; the conical end is nested and connected to the cavity opening of the valve cavity facing outward, and the valve stem is nested and connected to the outer end of the buffer valve seat; a valve core oil passage penetrating through the conical end and the valve stem is arranged inside the valve core; A valve seat sealing the conical section of the valve core is arranged at the cavity opening of the valve cavity; the valve seat is provided with an oil inlet and is communicated with the valve core oil passage of the valve core; an oil outlet is opened on the side wall of the valve sleeve close to the valve seat, and the oil outlet is conducted when the valve core is separated from the valve seat; the oil outlet is closed when the valve core abuts against the valve seat; A pressure regulating plug is arranged at the tail end of the valve body; A first buffer chamber and a valve seat oil passage are arranged inside the buffer valve seat; the end of the valve stem is nested and connected inside the first buffer chamber, and the valve seat oil passage penetrates through the buffer valve seat; a second buffer chamber communicated with the valve seat oil passage is formed between the buffer valve sleeve and the pressure regulating plug, and the area of the second buffer chamber acting on the buffer valve seat is larger than the area of the first buffer chamber acting on the buffer valve seat; A first gasket and a second gasket are slidably sleeved on the buffer valve seat; a first elastic member and a second elastic member are slidably sleeved on the valve stem; One side of the gasket one can abut against the pressure regulating plug, and the other side is connected to the conical end of the valve core through a first elastic member; One side of the gasket two can abut against the buffer valve seat, the other side can abut against the gasket one, and is connected to the conical end of the valve core through a second elastic member.

[0008] The technical effects achieved by the above settings are as follows: When the pressure oil enters the oil inlet P, the pressure oil acts on the valve core. The pressure oil enters the first buffer chamber through the valve core oil passage on the valve core. The pressure acting on the valve core overcomes the acting forces of the first elastic member and the second elastic member in the assembled state and the pressure in the first buffer chamber, causing the valve core to move towards the pressure regulating plug. The pressure oil at the oil inlet P enters the oil outlet T, and the pressure at the oil inlet P stops rising transiently, completing the first stage.

[0009] At the same time, the oil quickly fills the valve cavity. Since the area of the second buffer chamber acting on the buffer valve seat is larger than that of the first buffer chamber, the pressure oil overcomes the pressure in the first buffer chamber and the acting force of the second elastic member, pushing the buffer valve seat to move towards the oil inlet direction until the gasket two contacts the gasket one, and the second stage ends. During the whole process, the pressure at port P rises slowly, fully absorbing the pressure pulse at the oil inlet P.

[0010] Then the buffer valve seat compresses the first elastic member and the second elastic member simultaneously under the action of the pressure oil, and the pressure at port P rises rapidly until the gasket one reaches the set position, and the third stage ends.

[0011] When the buffer valve seat moves to the right, the pressure acting on the small end face on the left side of the valve core also gradually increases, and together with the pressures of the first elastic member and the second elastic member acting on the valve core, it overcomes the pressure of the oil inlet P acting on the valve core, causing the valve core to move to the right until the valve core is closed, and the passage between the oil inlet P and the oil outlet T is cut off. From the moment the pressure oil enters the oil inlet P until the valve core moves, the buffer valve seat moves to the left, and finally the valve core is closed. The whole process is very short. The main purpose achieved is to extend the pressure rise time and absorb the pressure pulse at the oil inlet P, which is equivalent to buffering the traveling pressure.

[0012] Further, the valve core oil passage includes a first oil passage, a first damping hole, and a second oil passage that sequentially extend from the conical end towards the valve stem end; The first oil passage communicates with the oil inlet of the valve seat; The inner diameter of the first oil passage is larger than the inner diameter of the second oil passage; The inner diameter of the second oil passage is larger than the inner diameter of the first damping hole.

[0013] Technical effects achieved by the above settings: The function of the first damping orifice is to filter out high-frequency pressure pulsations in the upstream hydraulic system and simultaneously achieve secondary pressure reduction of the hydraulic oil. The pressure after pressure reduction acts on the left end face of the buffer valve seat. At this time, the area of the left end face is larger than that of the right end face, and the pressure on the left end face is smaller than that on the right end face, that is, the pressure in the second buffer chamber reaches a certain level before the buffer valve seat can be pushed.

[0014] The first buffer chamber, as a volume space, is used to store or release hydraulic oil, further smoothing the pressure fluctuations, avoiding the direct action of pressure peaks on downstream components. At the same time, the back pressure generated by the first buffer chamber can slow down the movement speed of the spool, making the system pressure stable.

[0015] Further, the valve seat oil passage includes a second damping orifice, a third oil passage, and a fourth oil passage; The third oil passage communicates with the first buffer chamber through the second damping orifice; The inner diameter of the fourth oil passage is larger than that of the third oil passage; The inner diameter of the third oil passage is larger than that of the second damping orifice.

[0016] Technical effects achieved by the above settings: The function of the second damping orifice is to filter out high-frequency pressure pulsations in the upstream hydraulic system and simultaneously achieve secondary pressure reduction of the hydraulic oil. The back pressure effect of the second buffer chamber can also prevent the spool from hitting the pressure regulating plug quickly due to inertia, reducing mechanical vibration and noise, and prolonging the service life of the components.

[0017] Further, a first limiting step with an inner diameter smaller than the outer diameter of the first gasket is provided in the valve sleeve to limit the travel range of the first gasket.

[0018] Further, the first gasket is a hollow cylindrical shape, including an annular block and an annular wall; A round hole with a diameter larger than that of the second elastic member is provided in the middle of the annular block, and the second elastic member passes through the round hole and abuts against the second gasket; The annular wall fits and slides with the valve cavity; The second gasket is a hollow ring shape, sleeved on the buffer valve seat, and the outer diameter of the second gasket is smaller than the outer diameter of the annular wall.

[0019] Further, the pressure regulating plug is fixed by a locking nut.

[0020] Technical effects achieved by the above settings: During the working process, the hydraulic oil will impact the relief valve, and the pressure regulating plug may become loose due to the impact vibration. The locking nut (also called a locknut) is a common key component used in mechanical assembly to prevent the loosening of threaded connections.

[0021] Further, the pressure regulating plug is nested and slidably connected in the assembly cavity of the valve sleeve.

[0022] Further, a second limiting step with an inner diameter smaller than the outer diameter of the pressure regulating plug is arranged in the valve sleeve to limit the screwing-in depth of the pressure regulating plug.

[0023] The technical effects achieved by the above settings are as follows: By adjusting the screwing-in depth of the pressure regulating plug, the primary and secondary pressures of the system can be initially adjusted. The second limiting step limits the screwing-in depth of the pressure regulating plug.

[0024] Further, a sealing ring is arranged between the pressure regulating plug and the valve sleeve.

[0025] The technical effects achieved by the above settings are as follows: The sealing ring is between the pressure regulating plug and the valve sleeve, preventing external pollutants such as dust and moisture from entering the valve body, and at the same time preventing the oil from leaking out to the external environment. The cooperation clearance between the pressure regulating plug and the valve sleeve is the main seal, and the sealing ring is the auxiliary seal.

[0026] Further, the second buffer chamber is in a horn shape with an opening facing the pressure regulating plug.

[0027] The technical effects achieved by the above settings are as follows: The horn-shaped second buffer chamber can increase the initial acting area of the buffer valve seat. When the pressure rises to a certain level, the buffer valve seat is more likely to open and move to the right.

[0028] Further, both the first elastic member and the second elastic member are springs.

[0029] In a second aspect, the present invention also provides a method for using a two-stage buffer overflow valve. Based on the two-stage buffer overflow valve described in the first aspect, it includes the following steps: By adjusting the thicknesses of shim one and shim two and the screwing-in depth of the pressure regulating plug in the valve sleeve, the initial compression amounts of the first elastic member and the second elastic member are changed, thereby affecting the opening pressure of the overflow valve to meet different requirements for the maximum pressure of the walking motor.

[0030] In a third aspect, a walking motor includes the two-stage buffer overflow valve described in the first aspect.

[0031] In a fourth aspect, a construction machine includes the walking motor described in the third aspect.

[0032] Compared with the prior art, the beneficial effects achieved by the present invention are: 1. The present invention achieves primary buffering by compressing a small spring to replace the existing buffer piston. By making full use of the characteristic that the small spring has a low initial pressure and a high final pressure, the initial pressure of the primary pressure can be greatly reduced without affecting the final pressure, ensuring that the rotational inertia of the travel motor can be fully absorbed under low-speed and small-load conditions, thereby improving the starting impact and stopping impact problems of the travel motor under all working conditions.

[0033] 2. The reasonable starting pressure of the primary buffering of the present invention enables the overflow valve to fully absorb pressure pulses under different speed loads, avoiding the problem that the existing overflow valve cannot achieve buffering under different impact pressures; 3. Whether the present application adjusts the primary pressure by changing the thickness of the gasket or adjusting the position of the screw plug, it will not affect the final compression amount of the spring, that is, it will not have any impact on the set pressure of the overflow valve, ensuring the convenience and reliability of the debugging of the travel motor; 4. Since the overflow valve of the present invention adopts the form of internally and externally assembling large and small springs, the stiffness of the two springs can be independently designed and used according to needs. This flexibility enables the spring pressure regulating system to better adapt to different working loads and vibration environments. At the same time, the two springs are nested inside and outside, making them more compact in space and having a higher space utilization rate. Description of the Drawings

[0034] Figure 1 is a schematic structural diagram of the buffer overflow valve of the present invention; Figure 2 is a schematic structural diagram of the prior art CN202182080U; Figure 3 is a schematic structural diagram of the prior art CN118548266A; Figure 4 is a schematic diagram of the pressure impact debugging process of the prior art; Figure 5 is a schematic diagram of the pressure impact debugging process of the present invention; Figure 6 is a schematic structural diagram of the valve core of the present invention.

[0035] In the figure: 1, valve seat; 2, valve core; 3, first elastic member; 4, second elastic member; 5, first gasket; 6, second gasket; 7, sealing ring; 8, buffer valve seat; 9, valve sleeve; 10, lock nut; 11, pressure regulating screw plug; P, oil inlet; T, oil outlet; 2a, first oil passage; R1, first damping hole; 2b, second oil passage; K1, first limiting step; 8a, first buffer chamber; R2, second damping hole; K2, second limiting step; 9a, assembly cavity; 8b, third oil passage; 8c, fourth oil passage; 11a, second buffer chamber. Detailed Embodiments

[0036] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and cannot be used to limit the protection scope of the present invention.

[0037] In the description of this embodiment, it should be noted that when terms such as "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. appear, the orientation or positional relationship indicated is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing this embodiment and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, so it cannot be understood as a limitation to this embodiment. Embodiment 1

[0038] As Figure 1 shown, this embodiment provides a two-stage buffer overflow valve, including a valve sleeve 9; a valve cavity is provided inside the valve sleeve 9; a buffer valve seat 8 and a valve core 2 are axially slidably arranged in the valve cavity; As Figure 6 shown, the valve core 2 includes a conical end and a valve stem; the conical end is nested and connected to the cavity opening of the valve cavity facing outward, and the valve stem is nested and connected to the outer end of the buffer valve seat 8; a valve core oil passage penetrating through the conical end and the valve stem is provided inside the valve core 2; A valve seat 1 for sealing the conical section of the valve core 2 is provided at the cavity opening of the valve cavity; the valve seat 1 is provided with an oil inlet P and is communicated with the valve core oil passage of the valve core 2; an oil outlet T is opened on the side wall of the valve sleeve 9 close to the valve seat 1. When the valve core 2 is separated from the valve seat 1, the oil outlet T is conducted; when the valve core 2 is tightly abutted against the valve seat 1, the oil outlet T is closed; A pressure regulating plug 11 is provided at the tail end of the valve body; A first buffer chamber 8a and a valve seat 1 oil passage are provided inside the buffer valve seat 8; the end of the valve stem is nested and connected inside the first buffer chamber 8a, and the valve seat 1 oil passage penetrates through the buffer valve seat 8; a second buffer chamber communicated with the valve seat 1 oil passage is formed between the buffer valve sleeve 9 and the pressure regulating plug 11, and the area where the second buffer chamber 11a acts on the buffer valve seat 8 is larger than the area where the first buffer chamber 8a acts on the buffer valve seat 8; A first gasket 5 and a second gasket 6 are slidably sleeved on the buffer valve seat 8; a first elastic member 3 and a second elastic member 4 are slidably sleeved on the valve stem; One side of the first gasket 5 can abut against the pressure regulating plug 11, and the other side is connected to the conical end of the valve core 2 through the first elastic member 3; One side of the second gasket 6 can abut against the buffer valve seat 8, the other side can abut against the first gasket 5, and is connected to the conical end of the valve core 2 through the second elastic member 4.

[0039] Implementation principle: When pressure oil enters the oil inlet P, the pressure oil acts on the valve core 2. The pressure oil enters the first buffer chamber 8a through the valve core oil passage on the valve core 2. The pressure acting on the valve core 2 overcomes the acting force of the first elastic member 3 and the second elastic member 4 in the assembled state and the pressure of the first buffer chamber 8a, causing the valve core 2 to move towards the pressure regulating plug 11. The pressure oil at the oil inlet P enters the oil outlet T, and the pressure at the oil inlet P stops rising temporarily, completing the first stage.

[0040] Meanwhile, the oil quickly fills the valve cavity. Since the area of the second buffer chamber 11a acting on the buffer valve seat 8 is larger than that of the first buffer chamber 8a, the pressure oil overcomes the pressure of the first buffer chamber 8a and the acting force of the second elastic member 4, pushing the buffer valve seat 8 to move towards the oil inlet P. The second stage ends until the gasket two 6 contacts the gasket one 5. During the whole process, the pressure at port P rises slowly, fully absorbing the pressure pulse at the oil inlet P.

[0041] Then, the buffer valve seat 8 compresses the first elastic member 3 and the second elastic member 4 simultaneously under the action of the pressure oil, and the pressure at port P rises rapidly until the gasket one 5 reaches the set position, and the third stage ends.

[0042] When the buffer valve seat 1 moves to the right, the pressure acting on the small end face on the left side of the valve core 2 also gradually increases, and together with the pressure of the first elastic member 3 and the second elastic member 4 acting on the valve core 2, it overcomes the pressure of the oil inlet P acting on the valve core 2, causing the valve core 2 to move to the right until the valve core 2 is closed, and the passage between the oil inlet P and the oil outlet T is cut off. From the moment the pressure oil enters the oil inlet P until the valve core 2 moves, the buffer valve seat 8 moves to the left, and finally the valve core 2 is closed. The whole process is very short. The main purpose is to extend the pressure rise time and absorb the pressure pulse at the oil inlet P, which is equivalent to buffering the traveling pressure. Embodiment 2

[0043] Based on the same design principle as Embodiment 1, this embodiment provides a two-stage buffer overflow valve, including a valve sleeve 9; a valve cavity is arranged inside the valve sleeve 9; a buffer valve seat 8 and a valve core 2 are axially slidably arranged in the valve cavity; The valve core 2 includes a conical end and a valve stem; the conical end is nested and connected to the cavity opening of the valve cavity facing outward, and the valve stem is nested and connected to the outer end of the buffer valve seat 8; a valve core oil passage penetrating through the conical end and the valve stem is arranged inside the valve core 2; A valve seat 1 sealed with the conical section of the valve core 2 is arranged at the cavity opening of the valve cavity; the valve seat 1 is provided with an oil inlet P and is communicated with the valve core oil passage of the valve core 2; an oil outlet T is opened on the side wall of the valve sleeve 9 close to the valve seat 1. When the valve core 2 is separated from the valve seat 1, the oil outlet T is conducted; when the valve core 2 is tightly pressed against the valve seat 1, the oil outlet T is closed; A pressure regulating plug 11 is arranged at the tail end of the valve body; A first buffer chamber 8a and a valve seat 1 oil passage are provided inside the buffer valve seat 8; the end of the valve stem is nested and connected inside the first buffer chamber 8a, and the valve seat 1 oil passage penetrates through the buffer valve seat 8; a second buffer cavity communicating with the valve seat 1 oil passage is formed between the buffer valve sleeve 9 and the pressure regulating plug 11, and the area of the second buffer chamber 11a acting on the buffer valve seat 8 is larger than the area of the first buffer chamber 8a acting on the buffer valve seat 8; A first gasket 5 and a second gasket 6 are slidably sleeved on the buffer valve seat 8; a first elastic member 3 and a second elastic member 4 are slidably sleeved on the valve stem; One side of the first gasket 5 can abut against the pressure regulating plug 11, and the other side is connected to the conical end of the valve core 2 through the first elastic member 3; One side of the second gasket 6 can abut against the buffer valve seat 8, the other side can abut against the first gasket 5, and is connected to the conical end of the valve core 2 through the second elastic member 4.

[0044] Specifically, the valve core oil passage includes a first oil passage 2a, a first damping hole R1, and a second oil passage 2b that sequentially extend from the conical end to the valve stem end; The first oil passage 2a communicates with the oil inlet P of the valve seat 1; The inner diameter of the first oil passage 2a is larger than the inner diameter of the second oil passage 2b; The inner diameter of the second oil passage 2b is larger than the inner diameter of the first damping hole R1.

[0045] The function of the first damping hole R1 is to filter out high-frequency pressure pulsations in the upstream hydraulic system and at the same time achieve secondary decompression of the oil pressure. The pressure after decompression acts on the left end face of the buffer valve seat 8. At this time, the left end face area is larger than the right end face, and the left end face pressure is less than the right end face, that is, the pressure in the second buffer chamber 11a can push the buffer valve seat 8 only when it reaches a certain level.

[0046] The first buffer chamber 8a serves as a volume space for storing or releasing oil, further smoothing the pressure fluctuations, avoiding the direct action of pressure peaks on downstream components, and at the same time the back pressure generated by the first buffer chamber 8a can slow down the movement speed of the stable valve core 2, making the system pressure stable.

[0047] Specifically, the valve seat 1 oil passage includes a second damping hole R2, a third oil passage 8b, and a fourth oil passage 8c; The third oil passage 8b communicates with the first buffer chamber 8a through the second damping hole R2; The inner diameter of the fourth oil passage 8c is larger than the inner diameter of the third oil passage 8b; The inner diameter of the third oil passage 8b is larger than the inner diameter of the second damping hole R2.

[0048] The function of the second damping orifice R2 is to filter out high-frequency pressure pulsations in the upstream hydraulic system and simultaneously achieve secondary pressure reduction of the hydraulic oil. The backpressure effect of the second buffer chamber 11a can also prevent the spool 2 from rapidly hitting the pressure regulating plug 11 due to inertia, reduce mechanical vibration and noise, and extend the service life of the component.

[0049] Specifically, a first limiting step K1 with an inner diameter smaller than the outer diameter of the first gasket 5 is provided in the valve sleeve 9 to limit the travel range of the first gasket 5.

[0050] The first gasket 5 is a hollow cylindrical shape, including an annular block and an annular wall; A circular hole with a diameter larger than that of the second elastic member 4 is provided in the middle of the annular block, and the second elastic member 4 passes through the circular hole and abuts against the second gasket 6; The annular wall fits and slides with the valve cavity; The second gasket 6 is a hollow ring shape, sleeved on the buffer valve seat 8, and the outer diameter of the second gasket 6 is smaller than the outer diameter of the annular wall.

[0051] Specifically, the pressure regulating plug 11 is fixed by a lock nut 10. During the working process, the hydraulic oil will impact the relief valve, and the pressure regulating plug 11 may become loose due to the impact vibration. The lock nut 10 (also called a locking nut) is a commonly used key component in mechanical assembly to prevent the loosening of threaded connections.

[0052] The pressure regulating plug 11 is nested and slidably connected in the assembly cavity 9a of the valve sleeve 9.

[0053] A second limiting step K2 with an inner diameter smaller than the outer diameter of the pressure regulating plug 11 is provided in the valve sleeve 9 to limit the screwing-in depth of the pressure regulating plug 11. By adjusting the screwing-in depth of the pressure regulating plug 11, the primary and secondary pressures of the system can be preliminarily adjusted. The second limiting step K2 limits the screwing-in depth of the pressure regulating plug 11.

[0054] Specifically, a sealing ring 7 is provided between the pressure regulating plug 11 and the valve sleeve 9. The sealing ring 7 is between the pressure regulating plug 11 and the valve sleeve 9, preventing external contaminants such as dust and moisture from entering the valve body, and at the same time preventing the hydraulic oil from leaking out to the external environment. The sealing between the pressure regulating plug 11 and the valve sleeve 9 mainly relies on the mating clearance, and the sealing ring 7 serves as an auxiliary seal.

[0055] The buffer relief valve of the present invention realizes the buffer process of the relief valve through the combined use of large and small springs 4, and also has three stages during the pressure impact debugging process.

[0056] The time-pressure curve of this application is as Figure 5Shown as follows: In the first stage, the pressure before the overflow valve rises rapidly due to the closing of the main valve until the buffer valve core 2 is opened; in the second stage, the buffer valve seat 8 moves to the right under the oil pressure to compress the small spring 4 until the gasket one 5 and the gasket two 6 are in full contact; in the third stage, the buffer valve seat 8 continues to move to the right while compressing the large and small springs 4 until the gasket one 5 is disengaged from the first limit step K1.

[0057] a) Especially in the second stage, the rotational inertia is absorbed by compressing the small spring 4 through the buffer valve seat 8. The pressure gradually increases throughout the process. The initial pressure in the second stage (the starting pressure of the first-stage buffer) is determined by the thickness of the gasket two 6. The termination pressure in the second stage is determined by the first termination compression amount of the small spring 4. Since the position of the gasket one 5 does not change, replacing the thickness of the gasket two 6 does not affect the termination pressure in the second stage. Therefore, reasonably lowering the starting pressure of the first-stage buffer will enable sufficient absorption of impacts under different speed loads.

[0058] Taking the stop condition of the whole machine application as an example, when in the low-speed and small-load condition, its stop process is as follows: The high-pressure oil before the overflow valve passes through two-stage damping holes for pressure reduction and reaches the bottom of the buffer valve seat 8 to push it to move. In this process, the motor pressure first rises rapidly to the first-stage pressure (i.e., the initial pressure in the second stage), then the small spring 4 is compressed, and the rising speed of the oil pressure decreases. Due to the small load inertia, the pressure before the motor valve does not rise to the termination pressure in the second stage and then stops. The stop process of the whole machine in the high-speed and large-load condition is as follows: The overflow valve quickly reaches the first-stage pressure to compress the small spring 4 for the first buffer, and then compresses the large spring 3 to achieve the second buffer. In this way, under different inertia loads, pressure buffering can be achieved throughout the process of pressure jump, which can effectively improve the operating performance of the travel motor.

[0059] b) The buffer overflow valve of the present invention initially adjusts the first-stage pressure through a plug, and conducts two fine-tunings by adjusting the thicknesses of the gasket two 6 and the gasket one 5 to cope with the complex working conditions of the travel motor. At the same time, the final compression amount of the large and small springs 4 is limited by the first limit step K1. Whether adjusting the first-stage pressure by replacing the thicknesses of the gasket one 5 and the gasket two 6 or adjusting the position of the plug, it will not affect the final compression amount of the spring, that is, it will not have any impact on the set pressure of the overflow valve, ensuring the convenience and reliability of the debugging of the travel motor.

[0060] c) The overflow valve of the present invention adopts the form of internally and externally assembling the large and small springs 4. The stiffness of the two springs can be independently designed according to needs and used in combination. This flexibility enables the spring pressure regulating system to better adapt to different working loads and vibration environments. At the same time, the two springs (the first spring part and the second spring part) are nested inside and outside, which is more compact in space and has a higher space utilization rate.

[0061] Specific working principle: When the pressure oil enters the oil inlet P, the pressure oil acts on the spool 2. The pressure oil passes through the first oil passage 2a, the first damping hole R1, and the second oil passage 2b on the spool 2 and enters the first buffer chamber 8a. The pressure acting on the spool 2 overcomes the spring, the acting force in the assembled state, and the pressure in the first buffer chamber 8a, causing the spool 2 to move towards the plug direction. The pressure oil at the oil inlet P enters the oil outlet T, and the pressure at the oil inlet P stops rising transiently, completing the first stage. At the same time, the oil quickly fills the valve cavity. Since the second buffer chamber 11a is larger than the area of the first buffer chamber 8a acting on the buffer valve seat 8, the pressure oil overcomes the pressure in the first buffer chamber 8a and the acting force of the small spring 4, pushing the buffer valve seat 8 towards the oil inlet P direction until the second gasket 6 contacts the first gasket 5, and the second stage ends. Due to the low stiffness of the small spring 4, the port pressure rises slowly during the whole process, fully absorbing the pressure pulse at the oil inlet P. Then, the buffer valve seat 8 compresses the small spring 4 and the large spring 3 simultaneously under the action of the pressure oil, and the port pressure rises rapidly until the first gasket 5 contacts the first limit step K1, and the third stage ends.

[0062] When the buffer valve seat 1 moves to the right, the pressure acting on the small end face on the left side of the spool 2 also gradually increases, and together with the large and small springs 4 and the pressure acting on the spool 2, it overcomes the pressure of the oil inlet P acting on the spool 2, causing the spool 2 to move to the right until the spool 2 is closed, and the passage between the oil inlet P and the oil outlet T is cut off. From the moment the pressure oil enters the oil inlet P until the spool 2 moves, the buffer valve seat 8 moves to the left, and finally the spool 2 is closed. The whole process is very short, and the main purpose is to extend the pressure rise time and absorb the pressure pulse at the oil inlet P, which is equivalent to buffering the traveling pressure.

[0063] In addition, by adjusting the plug, the first gasket 5, and the second gasket 6, the opening pressure of the overflow valve can be changed, so as to meet the different requirements of the maximum pressure of the traveling motor.

[0064] In addition, it should be noted that the structure shown in this application is a two-stage buffer overflow valve, but it can also achieve the structure of a multi-stage buffer overflow valve by superimposing springs. Embodiment 3

[0065] This embodiment provides a method for using a two-stage buffer overflow valve. Based on the two-stage buffer overflow valve in Embodiment 2, it includes the following steps: a Achieve the overall pressure regulation range of the overflow valve by designing different stiffnesses of the first elastic member 3 and the second elastic member 4 and different depths of the limit steps; b Initially adjust the opening pressure of the overflow valve by adjusting the position of the pressure regulating plug 11; C Fine-tune the opening pressure of the overflow valve by adjusting the thicknesses of the first gasket 5 and the second gasket 6 to change the pre-compression amounts of the first elastic member 3 and the second elastic member 4.

[0066] The stiffness of the elastic element has been determined in the initial design and will not be changed during the debugging stage.

[0067] During the debugging stage, the initial compression amount of the elastic element is mainly changed by replacing the gasket and the screwing depth of the pressure regulating plug, so as to affect the opening pressure.

[0068] By the above method, the problems of excessive starting impact and stopping impact of the travel motor under all working conditions are solved. Embodiment 4

[0069] This embodiment provides a travel motor, including the two-stage buffer overflow valve described in Embodiment 2. Embodiment 5

[0070] This embodiment provides a construction machinery, including a travel motor described in Embodiment 4.

[0071] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, "a plurality" means two or more unless otherwise specifically defined.

[0072] In the present invention, unless otherwise clearly defined and limited, the terms such as "installed", "connected", "connected with", "fixed" and the like should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0073] In the present invention, unless otherwise clearly defined and limited, the first feature being "on" or "under" the second feature may include the direct contact between the first and second features, or may include the situation where the first and second features are not in direct contact but in contact through other features between them. Moreover, the first feature being "above", "over" and "on the top of" the second feature includes that the first feature is directly above and obliquely above the second feature, or merely means that the horizontal height of the first feature is higher than that of the second feature. The first feature being "under", "beneath" and "under the bottom of" the second feature includes that the first feature is directly below and obliquely below the second feature, or merely means that the horizontal height of the first feature is lower than that of the second feature.

[0074] In the description of this specification, the descriptions referring to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples", etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in a suitable manner in any one or more embodiments or examples.

[0075] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention without departing from the principles and spirit of the present invention.

Claims

1. A two-stage buffer overflow valve, characterized in that, It includes a valve sleeve; a valve cavity is arranged inside the valve sleeve; a buffer valve seat and a valve core are axially slidably arranged inside the valve cavity; The valve core includes a conical end and a valve stem; the conical end is nested and connected to the cavity opening of the valve cavity facing outward, and the valve stem is nested and connected to the outer end of the buffer valve seat; a valve core oil passage penetrating through the conical end and the valve stem is arranged inside the valve core; A valve seat sealed with the conical section of the valve core is arranged at the cavity opening of the valve cavity; the valve seat is provided with an oil inlet and is communicated with the valve core oil passage of the valve core; an oil outlet is opened on the side wall of the valve sleeve close to the valve seat, and when the valve core is separated from the valve seat, the oil outlet is conducted; A pressure regulating plug is arranged at the tail end of the valve body; A first buffer chamber and a valve seat oil passage communicated with each other are arranged inside the buffer valve seat; the end of the valve stem is nested and connected inside the first buffer chamber, and the valve seat oil passage penetrates through the buffer valve seat; a second buffer cavity communicated with the valve seat oil passage is formed between the buffer valve sleeve and the pressure regulating plug, and the area of the second buffer chamber acting on the buffer valve seat is larger than the area of the first buffer chamber acting on the buffer valve seat; A first gasket and a second gasket are slidably sleeved on the buffer valve seat; a first elastic member and a second elastic member are slidably sleeved on the valve stem; One side of the first gasket can abut against the pressure regulating plug, and the other side is connected to the conical end of the valve core through the first elastic member; One side of the second gasket can abut against the buffer valve seat, the other side can abut against the first gasket, and is connected to the conical end of the valve core through the second elastic member.

2. The secondary buffer overflow valve according to claim 1, wherein The valve core oil passage includes a first oil passage, a first damping hole and a second oil passage extending from the conical end to the valve stem end in sequence; The first oil passage is communicated with the oil inlet of the valve seat; The inner diameter of the first oil passage is larger than the inner diameter of the second oil passage; The inner diameter of the second oil passage is larger than the inner diameter of the first damping hole.

3. The secondary buffer overflow valve according to claim 2, characterized in that, The valve seat oil passage includes a second damping hole, a third oil passage and a fourth oil passage; The third oil passage is communicated with the first buffer chamber through the second damping hole; The inner diameter of the fourth oil passage is larger than the inner diameter of the third oil passage; The inner diameter of the third oil passage is larger than the inner diameter of the second damping hole.

4. The secondary buffer overflow valve according to claim 1, characterized in that, A first limiting step with an inner diameter smaller than the outer diameter of the first gasket is arranged inside the valve sleeve to limit the traveling range of the first gasket.

5. The secondary buffer overflow valve according to claim 1, wherein, The second buffer chamber is in a horn shape with an opening facing the pressure regulating plug.

6. The secondary buffer overflow valve according to claim 1, wherein, The first gasket is a hollow cylindrical shape and includes an annular block and an annular wall; A round hole with a diameter larger than the second elastic member is arranged in the middle of the annular block, and the second elastic member passes through the round hole and abuts against the second gasket; The annular wall fits and slides with the valve cavity; The second gasket is a hollow ring shape and is sleeved on the buffer valve seat, and the outer diameter of the second gasket is smaller than the outer diameter of the annular wall.

7. The secondary buffer overflow valve according to claim 1, characterized in that, The pressure regulating plug is fixed through a lock nut; The pressure regulating plug is nested and slidably connected in the assembly cavity of the valve sleeve.

8. The secondary buffer overflow valve according to claim 7, wherein, A second limiting step with an inner diameter smaller than the outer diameter of the pressure regulating plug is arranged inside the valve sleeve to limit the screwing depth of the pressure regulating plug.

9. The secondary buffer overflow valve according to claim 7, characterized in that, A sealing ring is arranged between the pressure regulating plug and the valve sleeve.

10. A method for using a two-stage buffer overflow valve, characterized in that, Based on the two-stage buffer overflow valve described in claim 1, it includes the following steps: By adjusting the gasket thicknesses of gasket one and gasket two and the screwing depth of the pressure regulating plug in the valve sleeve, the initial compression amounts of the first elastic member and the second elastic member are changed, thereby affecting the opening pressure of the overflow valve to meet different requirements for the highest pressure of the travel motor during use.

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