Variable damping passive oil damper and application thereof in railway vehicle

Abstract

The invention belongs to the technical field of shock absorber equipment, and particularly relates to a variable damping passive oil pressure shock absorber and application thereof in a railway vehicle, which comprises an oil storage cylinder assembly, and a working cylinder is coaxially arranged in the oil storage cylinder assembly, and is characterized in that a bottom valve assembly is pressed at the lower end of the working cylinder, and a pressure valve and a compensation valve are connected onto the bottom valve assembly; an O-shaped ring is arranged on the outer side of the bottom valve assembly and attached to the inner wall of the working cylinder, an air bag piece is connected between the inner wall of the oil storage cylinder assembly and the outer wall of the working cylinder, the upper end of the working cylinder is connected with a guide assembly, the guide assembly is attached to the inner wall of the oil storage cylinder assembly, a piston rod is arranged in the guide assembly in a penetrating mode, and the lower end of the piston rod is arranged in the working cylinder. The lower end of the piston rod is fixedly connected with a piston valve assembly, the oil storage cylinder assembly is sleeved with a sliding sleeve in sliding connection with the oil storage cylinder assembly, and the upper end of the sliding sleeve is connected with a joint bearing. And the practicability is high.

Description

Technical Field

[0001] The invention relates to the technical field of shock absorber equipment, in particular to a variable damping passive oil pressure shock absorber and application thereof in rail vehicles. Background Art

[0002] The history of human transportation is also the history of human development. Looking forward to the new century, my country's high-speed and ultra-high-speed train lines, which are mainly based on wheel-rail systems, will form a network across the country. In addition, at normal speed, the normal-conductor maglev train is particularly quiet and pollution-free, and the investment is less than that of the subway. In the future urban transportation, it will be warmly welcomed by residents. In the past, due to the relatively low speed of train operation, the effect of the shock absorber was not obvious. Therefore, people did not pay enough attention to it, and the performance of the shock absorber used was relatively low. Nowadays, "high speed and heavy load" is the development direction of railway operation. With the acceleration of the speed increase of trains, many unprecedented problems have emerged in the operation of locomotives and vehicles. Some of the problems have been solved after replacing the shock absorber. In view of the fact that the hydraulic shock absorber is one of the important components of the running mechanism of locomotives and vehicles, its performance directly affects the stability and safety of the operation of locomotives and vehicles. Therefore, during the operation of locomotives and vehicles, it is necessary to ensure that the shock absorber can maintain its performance reliability and stability. Today's high-speed trains and maglev trains are equipped with workshop shock absorbers, whose main function is to alleviate the swing amplitude of the two carriages and improve the overall stability of the vehicle.

[0003] A guide and a hydraulic shock absorber are disclosed in the patent application number CN202310205736.1. A guide sleeve installation groove is set on the piston rod through hole of the guide body, and a guide sleeve is fixedly installed in the guide sleeve installation groove. Since the guide sleeve is a metal guide sleeve, and the inner wall of the guide sleeve is slidably connected with the piston rod, and the outer wall of the guide sleeve is in contact with the groove wall of the guide sleeve installation groove, the guide sleeve can provide effective support to the piston rod while achieving sealing, avoiding the bending of the piston rod when the radial stiffness is insufficient, resulting in an increase in the sliding friction resistance between the piston rod and the guide, which causes oil leakage. Therefore, the guide and the hydraulic shock absorber provided by the present invention can solve the early oil leakage phenomenon when the shock absorber is placed in a horizontal position, and improve the stability of the dynamic damping performance of the shock absorber.

[0004] The Chinese patent application number CN202211258041.1 discloses a rail vehicle suspension shock absorber and a variable damping method. The variable damping control assembly in the rail vehicle suspension shock absorber of the present invention includes an active variable damping oil circuit and a passive variable damping oil circuit. The active variable damping oil circuit performs active variable damping according to the actual operating parameters of the shock absorber body, and adjusts the damping characteristics of the shock absorber in real time to meet the vibration reduction requirements. The passive variable damping oil circuit passively changes damping with the movement of the shock absorber body. When the active variable damping oil circuit is opened, active stepless variable damping within the load range is formed. When the active variable damping oil circuit is closed, passive variable damping within the load range is formed by the passive damping oil circuit, realizing automatic switching between active stepless variable damping and passive variable damping, and improving the vibration reduction reliability and operation stability of rail vehicles. However, the following problems still exist in practical applications, specifically: 1. No matter what kind of train, it cannot run on the track all the time, so it needs to frequently run on the track and the EMU depot and the repair depot. Most of the lines of the EMU depot and the repair depot have large curvature and large radius, so the vehicle needs to reduce to a certain speed when entering and leaving the depot to ensure the cornering performance; 2. When the cylinder reciprocates in the working area, stress concentration is generated at the junction of the two areas (working area and non-working area), causing damage to the Glay ring, affecting the sealing effect and causing failure; 3. During the process of using dustproof parts to protect the shock absorber from dust, dust will cover the dustproof parts during vehicle operation. Long-term dust accumulation will cause damage to the dustproof parts during the expansion and contraction of the shock absorber, resulting in failure of dust protection.

[0005] Therefore, the present invention provides a variable damping passive oil shock absorber and its application in a rail vehicle to solve the above problems. Summary of the invention

[0006] In view of the above situation, in order to overcome the defects of the prior art, the present invention provides a variable damping passive oil pressure shock absorber and its application in rail vehicles, which effectively solves the problem of achieving the effect of large damping with the installation size of the shock absorber in the normal operating line, stretching and compressing small damping when the vehicle enters and leaves the warehouse, thereby improving the cornering performance.

[0007] The present invention includes an oil storage cylinder assembly, wherein a working cylinder is coaxially mounted inside the oil storage cylinder assembly, and is characterized in that a bottom valve assembly is press-fitted at the lower end of the working cylinder, a pressure valve and a compensation valve are connected to the bottom valve assembly, an O-ring is arranged on the outer side of the bottom valve assembly, the O-ring fits the inner wall of the working cylinder, and an airbag is connected between the inner wall of the oil storage cylinder assembly and the outer wall of the working cylinder; The upper end of the working cylinder is connected with a guide assembly, the guide assembly is in contact with the inner wall of the oil storage cylinder assembly, a piston rod is passed through the guide assembly, the lower end of the piston rod is placed in the working cylinder, the lower end of the piston rod is fixedly connected with a piston valve assembly, the outer sleeve of the oil storage cylinder assembly is provided with a sliding sleeve slidably connected with the oil storage cylinder assembly, and the upper end of the sliding sleeve is connected with a joint bearing; The piston valve assembly comprises a piston valve seat, a plurality of valve holes are formed on the piston valve seat, the valve holes are divided into two groups, the valve holes in the two groups are in opposite directions, the valve holes in the two groups are staggered, the valve holes are in the shape of stepped holes, valve pins are connected inside the valve holes, and a piston spring is connected between the valve pins and the valve holes; The working cylinder is divided into two non-working areas and one working area, the working area is between the two non-working areas, the inner walls of the non-working areas of the working cylinder are provided with a plurality of equicircumferentially distributed unloading grooves, and the unloading grooves are rounded around.

[0008] Preferably, two sealing ring grooves distributed up and down are formed on the periphery of the piston valve seat, a metal piston ring is pressed into the sealing ring groove, and the metal piston ring is interference fit with the working cylinder.

[0009] Preferably, the piston valve seat includes an upper piston body and a lower piston body, the sealing ring grooves are respectively located on the upper piston body and the lower piston body, an upper retaining ring is provided at the lower end of the upper piston body, and a lower retaining ring matching with the upper retaining ring is provided at the upper end of the lower piston body, the upper retaining ring and the lower retaining ring are closed to form an anti-escape bayonet, a grid ring is connected to the inside of the anti-escape bayonet, and the outer ring side of the grid ring has the same cone angle as the upper and lower retaining rings after press-fitting.

[0010] Preferably, the guide assembly includes a plurality of sealing structures, a plurality of limiting ring grooves matching with the sealing structures are provided at the axis of the guide assembly, the sealing structure includes a limiting elastic ring matching with the limiting ring groove, and the limiting elastic ring is a hollow structure; An annular hydraulic warehouse is provided at the upper end of the guide assembly, a sliding piston is coaxially slidably connected inside the annular hydraulic warehouse, the sliding piston is tightly fitted to the inner wall of the annular hydraulic warehouse, a pressure cover is threadedly connected to the upper end of the annular hydraulic warehouse, a pressure spring is arranged between the pressure cover and the sliding piston, the pressure spring is always in a compressed state, the lower part of the annular hydraulic warehouse and the interior of the limiting elastic ring are connected through a soft conduit, and the interior of the annular hydraulic warehouse and the interior of the limiting elastic ring are both filled with hydraulic oil.

[0011] Preferably, the lower ring surface of the limiting elastic ring is in the shape of an inclined surface, so as to scrape off the oil on the piston rod.

[0012] Preferably, the lower end of the sliding sleeve is fixedly connected with a dustproof piece, the lower end of the dustproof piece is fixedly connected to the outer wall of the oil storage cylinder assembly, and the dustproof piece is a telescopic bellows structure.

[0013] Preferably, a plurality of ventilation holes are provided on the telescopic bellows, a one-way ventilation valve is installed in the ventilation holes, an air inlet hole is provided at the lower end of the telescopic bellows, and a one-way air inlet valve is connected to the air inlet hole.

[0014] The present invention improves the existing oil pressure shock absorber and has the following beneficial effects: 1. By setting up the oil storage cylinder assembly, the bottom valve assembly, the guide assembly, and dividing the working cylinder into the working area and the non-working area, and opening the unloading groove in the non-working area, the different damping effects in different areas are effectively achieved; 2. By arranging a sealing structure, an annular hydraulic chamber, a sliding piston, a pressure cover, a pressure spring and other mechanisms in the guide assembly, an effective seal between the guide assembly and the piston rod is effectively achieved, thereby improving the fit; 3. The sealing between the piston valve seat and the working cylinder is achieved by setting the sealing ring groove, metal piston ring, Gly ring, anti-escape bayonet and other structures; 4. The problem of cleaning the dust adhered to the telescopic bellows during the reciprocating sliding process of the shock absorber is effectively achieved by arranging structures such as the telescopic bellows, the vent hole, the one-way vent valve, the air inlet hole and the one-way air inlet valve. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the three-dimensional structure of the present invention.

[0016] Figure 2 It is a schematic cross-sectional view of the present invention.

[0017] Figure 3 For the present invention Figure 2 A partial enlarged schematic diagram in the middle.

[0018] Figure 4 For the present invention Figure 2 A partial enlarged schematic diagram of point B in the middle.

[0019] Figure 5 For the present invention Figure 2 A partial enlarged schematic diagram of point C in the middle.

[0020] Figure 6 It is a schematic cross-sectional view of the guide seal assembly of the present invention.

[0021] Figure 7This is a schematic diagram of the valve pin structure of this invention.

[0022] Figure 8 Schematic diagram of the working cylinder structure of the present invention Figure 1 .

[0023] Fig. 9 Schematic diagram of the working cylinder structure of the present invention Figure 2 .

[0024] Fig.10 Schematic diagram of the piston valve seat structure.

[0025] Fig.11 Indicator curve diagram for operation in non-working area.

[0026] 1. The oil storage cylinder assembly; 2. The working cylinder; 3. The bottom valve assembly; 4. The pressure valve; 5. The compensation valve; 6. The O-ring; 8. The guide assembly; 9. The piston rod; 11. The sliding sleeve; 12. The spherical bearing; 13. The piston valve seat; 14. The valve hole; 15. The valve pin; 16. The piston spring; 17. The non-working area; 18. The working area; 19. The unloading groove; 20. The sealing ring groove; 21. The metal piston ring; 22. The upper piston body; 23. The lower piston body; 24. The upper retaining ring; 25. The lower retaining ring; 26. The anti-escape bayonet; 27. The grid ring; 28. The limiting ring groove; 29. ​​The limiting elastic ring; 30. The annular hydraulic chamber; 31. The sliding piston; 32. The pressure cover; 33. The pressure spring; 35. The dustproof part; 37. The one-way vent valve; 38. The air inlet hole; 39. The one-way air inlet valve. DETAILED DESCRIPTION

[0027] The above and other technical contents, features and effects of the present invention are described in detail below with reference to the attached Figures 1 to 11 The detailed description of the embodiments will clearly show that the structural contents mentioned in the following embodiments are all based on the drawings in the specification.

[0028] Exemplary embodiments of the present invention will be described below with reference to the accompanying drawings.

[0029] The present invention includes an oil storage cylinder assembly 1, wherein a working cylinder 2 is coaxially installed inside the oil storage cylinder assembly 1, a bottom valve assembly 3 is press-fitted on the lower end of the working cylinder 2, a pressure valve 4 and a compensation valve 5 are connected to the bottom valve assembly 3, the oil storage cylinder assembly 1 and the oil in the working cylinder 2 flow alternately through the pressure valve 4 and the compensation valve 5, an O-ring 6 is provided on the outer side of the bottom valve assembly 3, the O-ring 6 is in contact with the inner wall of the working cylinder 2, and the sealing between the working cylinder 2 and the bottom valve assembly 3 is achieved through the O-ring 6, an airbag component is connected between the inner wall of the oil storage cylinder assembly 1 and the outer wall of the working cylinder 2, and the airbag component is used to adapt to the volume changes of the oil in the working cylinder 2 and the oil storage cylinder assembly 1, so that the airbag component adapts to the changes in the internal pressure of the oil storage cylinder assembly 1, thereby ensuring the stability of the oil in the oil storage cylinder assembly 1.

[0030] The upper end of the working cylinder 2 is connected with a guide assembly 8, and the guide assembly 8 fits with the inner wall of the oil storage cylinder. The sealing of the working cylinder 2 and the upper end of the oil storage cylinder assembly 1 is achieved through the guide assembly 8. A piston rod 9 is passed through the guide assembly 8, and the lower end of the piston rod 9 is placed in the working cylinder 2. The lower end of the piston rod 9 is fixedly connected to the piston valve assembly. The outer sleeve of the oil storage cylinder assembly 1 is provided with a sliding sleeve 11 that is slidably connected to the oil storage cylinder assembly 1. The upper end of the sliding sleeve 11 is connected to a joint bearing 12. During the compression process of the shock absorber, the oil in the lower chamber inside the working cylinder 2 enters the upper chamber through the piston valve assembly. At the same time, part of the oil in the lower chamber will occupy part of the space due to the downward compression process of the piston rod 9. Part of the oil in the working cylinder 2 enters the oil storage cylinder assembly 1 through the bottom valve assembly 3. When the piston rod 9 slides upward, the oil in the oil storage cylinder assembly 1 enters the working cylinder 2. At the same time, the oil in the upper chamber of the working cylinder 2 enters the lower chamber of the working cylinder 2 through the piston valve assembly.

[0031] The piston valve assembly includes a piston valve seat 13, which is fixedly connected to the piston rod 9. A plurality of valve holes 14 are formed on the piston valve seat 13. The valve holes 14 are divided into two groups. The two groups of valve holes 14 are in opposite directions and are staggered. The valve holes 14 are in the shape of stepped holes. Valve pins 15 are connected to the inside of the valve holes 14. A piston spring 16 is connected between the valve pin 15 and the valve hole 14. During the sliding process of the piston valve assembly, the oil in the working cylinder 2 flows between the upper chamber and the lower chamber of the working cylinder 2 through different valve holes 14, thereby forming a damping effect.

[0032] The working cylinder 2 is divided into two non-working areas 17 and a working area 18. The working area 18 is between the two non-working areas 17. The inner wall of the non-working area 17 of the working cylinder 2 is provided with a plurality of unloading grooves 19 with equal circumferential distribution. The unloading grooves 19 are rounded around, and the unloading grooves 19 play a role of unloading. During compression and stretching, the oil in the working cylinder 2 is more likely to pass through the position of the unloading groove 19 with a large cross-sectional area due to the small cross-sectional area and high pressure of the valve hole 14 of the piston valve assembly through the channel priority. Through the setting of the unloading grooves, different damping effects of rail vehicles in different sections are achieved.

[0033] During the specific implementation of this embodiment, when the shock absorber is compressed in the working area 18, the piston rod 9 is compressed downward, and most of the oil in the lower chamber of the working cylinder 2 enters the upper chamber of the working cylinder 2 through the piston valve assembly. When sliding at a low speed, the oil passes through the normal through hole on the valve pin 15. At the same time, when the piston rod 9 slides at a high speed, the valve pin 15 slides in the opposite direction of the compression, and the oil is discharged through the valve hole 14 and the normal through hole on the valve pin 15. At the same time, due to the compression process of the piston rod 9, the piston rod 9 will occupy a certain volume, so a small part of the oil in the lower chamber of the working cylinder 2 will enter the oil storage cylinder assembly 1 through the bottom valve assembly 3. When the shock absorber is stretched, the direction of the oil is opposite to the flow direction of the piston rod 9 during the compression process. When the shock absorber is compressed in the non-working area 17, the piston valve assembly is in the sliding process. Under the action of pressure, the oil in the working cylinder 2 preferentially flows out from the unloading groove 19 on the side wall of the working cylinder 2, and passes through the piston valve assembly as little as possible, thereby achieving a smaller damping force generated by the shock absorber in the non-working area 17.

[0034] In order to improve the sealing between the piston valve seat 13 and the working cylinder 2 and improve the damping effect of the piston valve assembly in the working area 18, the present embodiment provides a structure for enhancing the sealing between the piston valve assembly and the inner wall of the working cylinder 2. Specifically, two sealing ring grooves 20 distributed up and down are provided on the periphery of the piston valve seat 13. A metal piston ring 21 is pressed into the inside of the sealing ring groove 20. The metal piston ring 21 and the working cylinder 2 are interference fit, which improves the sealing between the piston valve assembly and the inner wall of the working cylinder 2 and ensures the guiding function during the overall movement.

[0035] In order to facilitate the assembly of the piston valve assembly and to facilitate the replacement of internal components when the piston valve assembly fails, the piston valve seat 13 includes an upper piston body 22 and a lower piston body 23. The sealing ring groove 20 is respectively located on the upper piston body 22 and the lower piston body 23, so that the metal piston ring 21 fits the inner wall of the working cylinder 2. The lower end of the upper piston body 22 is provided with an upper retaining ring 24, and the upper end of the lower piston body 23 is provided with a lower retaining ring 25 that matches the upper retaining ring 24. The upper retaining ring 24 and the lower retaining ring 25 are closed to form an anti-escape bayonet 26, and the anti-escape bayonet 26 is internally provided. A Gly ring 27 is connected. After press-fitting, the outer ring side of the Gly ring 27 has the same conical angle as the upper retaining ring 24 and the lower retaining ring 25. The piston valve seat 13 and the inside of the working cylinder 2 are sealed by the Gly ring 27. At the same time, the conical angles of the Gly ring 27 and the upper retaining ring 24 and the lower retaining ring 25 are consistent, which effectively prevents the Gly ring 27 from falling out and avoids the reciprocating sliding process of the piston valve assembly in the working cylinder 2. Stress concentration is generated at the junction of the working area 18 and the non-working area 17, which leads to the breakage of the Gly ring 27, affecting the overall sealing effect and causing failure.

[0036] In order to achieve effective sealing between the guide assembly 8 and the piston rod 9 and avoid oil leakage, the guide assembly 8 includes a plurality of sealing structures. A plurality of limiting ring grooves 28 matching the sealing structure are opened at the axis of the guide assembly 8. The sealing structure includes a limiting elastic ring 29 matching the limiting ring groove 28. The limiting elastic ring 29 is a hollow structure. The sealing between the guide assembly 8 and the piston rod 9 is achieved through the contact between the limiting elastic ring 29 and the piston rod 9. The limiting elastic ring 29 is made of elastic material to achieve sealing between the guide assembly 8 and the piston rod 9.

[0037] In order to ensure that the limiting elastic ring 29 and the piston rod 9 fit closely and enhance the sealing performance, and at the same time, during the wear process of the limiting elastic ring 29, the effective fit between the piston rod 9 and the limiting elastic ring 29 can be ensured, an annular hydraulic warehouse 30 is provided at the upper end of the guide assembly 8, and a sliding piston 31 is coaxially slidably connected inside the annular hydraulic warehouse 30, and the sliding piston 31 and the inner wall of the annular hydraulic warehouse 30 fit closely, and a pressure cover 32 is threadedly connected to the upper end of the annular hydraulic warehouse 30, and a pressure spring 33 is arranged between the pressure cover 32 and the sliding piston 31, and the pressure spring 33 is always in a compressed state state, the sliding piston 31 is pressed by the pressure spring 33, so that the interior of the annular hydraulic warehouse 30 is in a high-pressure state, the lower part of the annular hydraulic warehouse 30 and the interior of the limiting elastic ring 29 are connected through a soft conduit, the interior of the annular hydraulic warehouse 30 and the interior of the limiting elastic ring 29 are filled with hydraulic oil, and the hydraulic oil in the limiting elastic ring 29 is in a high-pressure state through the extrusion of the sliding piston 31, thereby achieving effective and tight fit between the limiting elastic ring 29 and the piston rod 9, thereby enhancing the sealing between the guide assembly 8 and the piston rod 9, and no oil leakage occurs.

[0038] During the reciprocating sliding process of the piston rod 9, hydraulic oil will adhere to the piston rod 9. During the relative sliding process between the piston rod 9 and the guide assembly 8, the oil will be retained on the upper end surface of the guide assembly 8, causing oil leakage. Therefore, in order to improve the internal stability of the shock absorber and to avoid oil leakage from the shock absorber, the lower ring surface of the limiting elastic ring 29 is an inclined surface, so that the oil on the piston rod 9 can be scraped off when the piston rod 9 slides downward.

[0039] In order to achieve dust-proof treatment inside the shock absorber and prevent the dust from entering the oil storage cylinder assembly 1 during the sliding process of the sliding sleeve 11, thereby affecting the oil quality and causing wear on the wall surfaces inside the working cylinder 2 and the oil storage cylinder assembly 1, thereby affecting the damping performance, a dust-proof part 35 is fixedly connected to the lower end of the sliding sleeve 11, and the lower end of the dust-proof part 35 is fixedly connected to the outer wall of the oil storage cylinder assembly 1. The dust-proof part 35 is a telescopic bellows structure, which drives the telescopic bellows to expand and contract during the reciprocating sliding process of the sliding sleeve 11, thereby achieving sealing of the interior of the shock absorber.

[0040] During the application of the shock absorber in rail vehicles, due to the complexity of the application environment, a large amount of dust will adhere to the telescopic bellows. In order to avoid excessive dust accumulation, which will affect the telescopicity of the telescopic bellows and even cause damage during the telescopic process, this embodiment provides a structure for pre-dusting the telescopic bellows to avoid a large amount of dust accumulation. Specifically, a plurality of vents are provided on the telescopic bellows, and a one-way vent valve 37 is installed in the vent hole, so that the gas in the area formed between the telescopic bellows and the outer wall of the oil storage cylinder assembly 1 can be prevented from condensing. The air is discharged to the outside through the one-way vent valve 37, thereby blowing away the dust on the outer surface of the telescopic bellows and causing the dust to fall off the outer surface of the telescopic bellows. At the same time, in order to replenish the gas to the inside of the telescopic bellows in time, an air inlet hole 38 is provided at the lower end of the telescopic bellows, and a one-way air inlet valve 39 is connected to the air inlet hole 38. During the process of stretching the telescopic bellows, the outside gas enters the inside of the telescopic bellows through the one-way air inlet valve 39, thereby realizing the circulation of the gas inside the telescopic bellows.

[0041] The above-mentioned embodiments are only preferred embodiments of the present invention and cannot be used to limit the scope of protection of the present invention. Any non-substantial changes and substitutions made by technicians in this field on the basis of the present invention shall fall within the scope of protection required by the present invention.

Claims

1. A variable damping passive oil pressure shock absorber, comprising an oil storage cylinder assembly (1), wherein a working cylinder (2) is coaxially mounted inside the oil storage cylinder assembly (1), characterized in that: A bottom valve assembly (3) is press-fitted at the lower end of the working cylinder (2), a pressure valve (4) and a compensation valve (5) are connected to the bottom valve assembly (3), an O-ring (6) is arranged on the outer side of the bottom valve assembly (3), the O-ring (6) is in contact with the inner wall of the working cylinder (2), and an airbag is connected between the inner wall of the oil storage cylinder assembly (1) and the outer wall of the working cylinder (2); The upper end of the working cylinder (2) is connected to a guide assembly (8), the guide assembly (8) and the inner wall of the oil storage cylinder assembly (1) are in contact with each other, a piston rod (9) is inserted into the guide assembly (8), the lower end of the piston rod (9) is placed in the working cylinder (2), the lower end of the piston rod (9) is fixedly connected to a piston valve assembly, the outer sleeve of the oil storage cylinder assembly (1) is provided with a sliding sleeve (11) which is slidably connected to the oil storage cylinder assembly (1), and the upper end of the sliding sleeve (11) is connected to a joint bearing (12); The working cylinder (2) is divided into two non-working areas (17) and a working area (18), wherein the working area (18) is between the two non-working areas (17), and the inner wall of the non-working area (17) of the working cylinder (2) is provided with a plurality of unloading grooves (19) with equal circumferential distribution, and the unloading grooves (19) are rounded around their peripheries.

2. The variable damping passive oil shock absorber according to claim 1, characterized in that: The piston valve assembly comprises a piston valve seat (13), a plurality of valve holes (14) are formed on the piston valve seat (13), the valve holes (14) are divided into two groups, the two groups of valve holes (14) are in opposite directions, the two groups of valve holes (14) are staggered, the valve holes (14) are in the shape of stepped holes, the inside of the valve holes (14) are connected with valve pins (15), and a piston spring (16) is connected between the valve pins (15) and the valve holes (14).

3. The variable damping passive oil shock absorber according to claim 2, characterized in that: The periphery of the piston valve seat (13) is provided with two sealing ring grooves (20) distributed vertically, a metal piston ring (21) is pressed into the sealing ring groove (20), and the metal piston ring (21) and the working cylinder (2) are interference-fitted.

4. The variable damping passive oil shock absorber according to claim 3, characterized in that: The piston valve seat (13) comprises an upper piston body (22) and a lower piston body (23), the sealing ring groove (20) being respectively located on the upper piston body (22) and the lower piston body (23), the lower end of the upper piston body (22) being provided with an upper retaining ring (24), the upper end of the lower piston body (23) being provided with a lower retaining ring (25) matching with the upper retaining ring (24), the upper retaining ring (24) and the lower retaining ring (25) being closed to form an anti-escape bayonet (26), the anti-escape bayonet (26) being internally connected with a grid ring (27), and the outer ring side of the grid ring (27) after press-fitting has the same conical angle as the upper retaining ring (24) and the lower retaining ring (25).

5. The variable damping passive oil shock absorber according to claim 4, characterized in that: The guide assembly (8) comprises a plurality of sealing structures. The guide assembly (8) is provided with a plurality of limiting ring grooves (28) at the axis thereof and matched with the sealing structures. The sealing structure comprises a limiting elastic ring (29) matched with the limiting ring groove (28). The limiting elastic ring (29) is a hollow structure. An annular hydraulic chamber (30) is provided at the upper end of the guide assembly (8), a sliding piston (31) is coaxially slidably connected inside the annular hydraulic chamber (30), the sliding piston (31) and the inner wall of the annular hydraulic chamber (30) are tightly fitted, a pressure cover (32) is threadedly connected to the upper end of the annular hydraulic chamber (30), a pressure spring (33) is arranged between the pressure cover (32) and the sliding piston (31), the pressure spring (33) is always in a compressed state, the lower part of the annular hydraulic chamber (30) and the interior of the limiting elastic ring (29) are connected via a soft conduit, and the interior of the annular hydraulic chamber (30) and the interior of the limiting elastic ring (29) are both filled with hydraulic oil.

6. The variable damping passive oil shock absorber according to claim 5, characterized in that: The lower ring surface of the limiting elastic ring (29) is in the shape of an inclined surface, so as to achieve the purpose of scraping off the oil on the piston rod (9).

7. The variable damping passive oil shock absorber according to claim 6, characterized in that: The lower end of the sliding sleeve (11) is fixedly connected to a dustproof part (35), and the lower end of the dustproof part (35) is fixedly connected to the outer wall of the oil storage cylinder assembly (1), and the dustproof part (35) is a telescopic bellows structure.

8. The variable damping passive oil shock absorber according to claim 7, characterized in that: The telescopic bellows is provided with a plurality of ventilation holes, each of which is provided with a one-way ventilation valve (37). The lower end of the telescopic bellows is provided with an air inlet hole (38), each of which is connected with a one-way air inlet valve (39).

9. Application of variable damping passive oil pressure shock absorber in rail vehicles, characterized in that: Use the variable damping passive oil shock absorber as claimed in claim 8.

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