A buffer device for a linear reciprocating hydraulic cylinder

Abstract

The application discloses a buffer device of a linear reciprocating motion type hydraulic cylinder, and mainly comprises a one-way valve assembly, a hydraulic cylinder moving part, a cylinder sleeve and a piston cavity. The free moving sealing body in the one-way valve assembly is used as a control element to control the opening and closing of the one-way valve hydraulic fluid passage, so that the hydraulic flow area of the buffer device is variable, the impact on the hydraulic cylinder moving part at the motion end point is reduced, and the hydraulic cylinder moving part can reach the end point position in time. The opening and closing time of the one-way valve hydraulic fluid passage can be variable according to the moving speed of the hydraulic cylinder moving part and the flow rate of the fluid, and the structure is simple, so that the buffer demand of the hydraulic cylinder moving part under variable working conditions can be met. The application solves the mutual contradiction between the hydraulic cylinder stop lag and the hydraulic cylinder impact in the prior art, and has important significance for improving the safety of the reciprocating motion type hydraulic cylinder.

Description

Technical Field

[0001] This invention relates to hydraulic cylinders, which are actuators in hydraulic transmission systems, and more specifically to a hydraulic buffer device with a variable hydraulic flow area for linear reciprocating hydraulic cylinders. Background Technology

[0002] In hydraulic systems, hydraulic cylinders are used as actuators to drive mechanisms with a certain mass. When the moving parts of the hydraulic cylinder (hydraulic piston or hydraulic plunger) reach the end of their stroke, they possess significant kinetic energy. If no deceleration is implemented, the moving parts of the hydraulic cylinder will collide mechanically with the cylinder head, generating impact, noise, and causing damage. To mitigate and prevent this hazard, a buffer device needs to be installed in the hydraulic circuit or inside the cylinder.

[0003] Traditional hydraulic buffer devices employ a method of installing a one-way damping orifice at the end point of the hydraulic cylinder's movement. This method has certain drawbacks. Because the damping effect is present throughout the reverse movement of a linear reciprocating hydraulic cylinder, the duration of the damping effect cannot be changed. Therefore, when the damping effect is strong, the piston or plunger moves slowly throughout the entire process, which not only leads to increased oil temperature but also causes lag in the hydraulic cylinder's stopping. When the damping is weak, the piston or plunger moves rapidly, generating impact. Thus, the lag in the hydraulic cylinder's stopping and the impact in the hydraulic cylinder are contradictory. This method suffers from problems such as high energy consumption and lag in the hydraulic cylinder's stopping or impact in the hydraulic cylinder.

[0004] Chinese utility model patent CN217950485U discloses an actuator with a seated buffer structure and a hydraulic fully variable valve mechanism. This mechanism utilizes a one-way valve, a buffer cone surface on the piston top section, and an oil hole on the side wall of the piston sleeve to control the speed at the end of the valve movement, thereby reducing the impact of the valve on the engine. However, this mechanism has some drawbacks: the one-way valve in this mechanism is controlled by a movable steel ball driven by hydraulic fluid. The steel ball in the one-way valve is close to the oil passage of the one-way valve, making the inverted cone area formed by the steel ball and the oil passage smaller than the area of ​​the oil passage, thus creating throttling. During the engine valve seating process, the steel ball is attracted to the one-way valve oil passage, keeping the one-way valve closed throughout the entire valve seating process. Oil in the piston chamber can only flow out through the side wall oil hole. At this time, the valve experiences a certain degree of damping. At the end of the valve movement, the side wall oil hole is blocked, resulting in further damping. This leads to a delayed seating problem when the valve moves slowly, and the continuous throttling causes the oil temperature to rise. During the engine valve opening process, the oil flowing into the piston chamber through the one-way valve oil passage is also subject to throttling, resulting in a reduced valve opening speed and increased oil temperature. Furthermore, this mechanism is only suitable for situations where the valve piston moves up and down reciprocating and the one-way valve is located above the valve piston, limiting its applicability. Summary of the Invention

[0005] This invention addresses the existing technical problems of buffer devices in linear reciprocating hydraulic cylinders by providing a hydraulic buffer device with a variable flow area. This reduces the impact on the moving parts of the hydraulic cylinder at the end of their motion and ensures that the moving parts reach their final position in a timely manner. Its main feature is that the minimum flow area of ​​the check valve in this buffer device is controlled by the moving parts of the hydraulic cylinder. This allows the opening and closing timing of the check valve to change according to the moving speed of the hydraulic cylinder parts and the flow rate of the fluid. Furthermore, the structure is simple and can meet the buffering requirements of the moving parts of the hydraulic cylinder under varying operating conditions, avoiding the contradictory problems of hydraulic cylinder stopping lag and hydraulic cylinder impact.

[0006] This invention discloses a buffer device for a linear reciprocating hydraulic cylinder, comprising a one-way valve assembly, a hydraulic cylinder moving part, a cylinder liner, and a hydraulic chamber; wherein:

[0007] A one-way valve assembly includes a one-way valve seat, a one-way valve cover, and a free-moving seal. The one-way valve seat has a hydraulic fluid passage for the one-way valve. When the free-moving seal is located on the one-way valve seat, the free-moving seal and the one-way valve seat form a seal, at which point the one-way valve is closed. When the free-moving seal is located on the one-way valve cover, an inverted conical minimum flow area is formed between the free-moving seal and the one-way valve seat. This inverted conical minimum flow area is larger than the area of ​​the hydraulic fluid passage for the one-way valve.

[0008] The cylinder liner provides support and guidance for the moving parts of the hydraulic cylinder. One end of the cylinder liner is connected to the one-way valve cover.

[0009] The moving parts of the hydraulic cylinder reciprocate linear motion within both ends of the cylinder sleeve. When they move close to the one-way valve assembly, they push the free-moving sealing body toward the one-way valve seat.

[0010] The hydraulic chamber mainly consists of a cylinder liner, the end face of the moving parts of the hydraulic cylinder, and a one-way valve cover. The hydraulic chamber is equipped with a bypass channel. When the one-way valve is open, the fluid medium in the hydraulic chamber exchanges with the outside through the bypass channel and the hydraulic fluid channel of the one-way valve. When the one-way valve is closed, the fluid medium inside the hydraulic chamber flows out only through the bypass channel.

[0011] When the moving parts of the hydraulic cylinder approach the check valve assembly within the cylinder liner, they push the free-moving seal towards the check valve seat, causing the minimum flow area of ​​the inverted cone formed between the check valve seat and the free-moving seal to be smaller than the hydraulic fluid passage area of ​​the check valve. In this situation, when the moving parts of the hydraulic cylinder move quickly, the fluid velocity at the minimum flow area of ​​the inverted cone formed between the check valve seat and the free-moving seal is high, and the free-moving seal is attracted to the check valve seat, causing the check valve to close quickly. When the moving parts of the hydraulic cylinder move slowly, the fluid velocity is low, and the free-moving seal is not attracted to the check valve seat, at which point the check valve remains open.

[0012] Furthermore, the inverted cone-shaped minimum flow area The area of ​​the minimum flow channel in the inverted cone shape Larger than the area of ​​the hydraulic fluid passage of the check valve Where L is the distance from the free-moving seal to the one-way valve seat; r is the radius of the hydraulic fluid passage of the one-way valve; and R is the radius of the free-moving seal.

[0013] Furthermore, the hydraulic cylinder moving part has a recessed structure at the center of the end near the one-way valve assembly, and the shape of the recessed structure matches the surface shape of the free-moving seal; when the hydraulic cylinder moving part moves close to the one-way valve assembly, it will push the free-moving seal to move.

[0014] Furthermore, the central recess of the hydraulic cylinder moving part near the one-way valve assembly is provided on a protrusion of a certain height.

[0015] Furthermore, the freely movable sealing body in the one-way valve assembly can be a rotating body such as a ball or a cone.

[0016] Furthermore, a countersunk through hole matching the free-moving seal body is provided at the center of the one-way valve cover. The diameter of the through hole is smaller than the diameter of the free-moving seal body, while the diameter of the countersunk hole is larger than the diameter of the free-moving seal body.

[0017] Furthermore, the bypass channel can be one or more, and the flow area of ​​the bypass channel can be fixed or variable.

[0018] Furthermore, the variable throttling channel is achieved by a U-shaped bypass channel provided on the cylinder liner, and the U-shaped groove on the side of the cylinder liner is gradually covered or gradually opened as the hydraulic cylinder moving parts move.

[0019] Furthermore, the moving parts of the hydraulic cylinder have a hollow structure inside.

[0020] Furthermore, in the one-way valve assembly, a spring is added between the freely movable sealing body and the one-way valve seat.

[0021] The working principle of a buffer device for a linear reciprocating hydraulic cylinder according to the present invention is as follows:

[0022] The one-way valve of this buffer device uses a free-moving sealing body as its control element, which can move between the one-way valve seat and the one-way valve cover. When the free-moving sealing body contacts the one-way valve seat to form a seal, the one-way valve is closed; otherwise, it is in the open state.

[0023] When the hydraulic cylinder moving component moves close to the check valve assembly, it pushes the free-moving seal towards the check valve seat, reducing the inverted conical minimum flow area formed between the check valve seat and the free-moving seal. When this inverted conical minimum flow area becomes smaller than the hydraulic fluid passage area of ​​the check valve, throttling occurs. In this situation, if the hydraulic cylinder moving component moves quickly, the fluid velocity at the inverted conical minimum flow area formed between the check valve seat and the free-moving seal is high. According to Bernoulli's principle: (i.e., pressure energy + kinetic energy + gravitational potential energy = constant) It can be seen that the fluid kinetic energy increases and the pressure energy decreases at the minimum flow area of ​​the inverted cone formed between the check valve seat and the free-moving seal. The resulting pressure difference overcomes the gravity or spring force of the free-moving seal, drawing it to the check valve seat and causing the check valve to close quickly. At this time, the fluid medium in the hydraulic chamber can only flow out through the bypass channel, and the fluid outflow velocity inside the hydraulic chamber decreases significantly. Therefore, the speed of the moving parts of the hydraulic cylinder decreases rapidly, avoiding impact with the end, and ultimately achieving a soft landing. If the moving parts of the hydraulic cylinder move slowly, the fluid velocity at the minimum flow area of ​​the inverted cone formed between the check valve seat and the free-moving seal is low. According to Bernoulli's principle, the pressure difference generated at the minimum flow area of ​​the inverted cone formed between the check valve seat and the free-moving seal is insufficient to overcome the gravity or spring force of the free-moving seal, so the check valve remains open. At this point, the fluid medium in the hydraulic chamber flows out through the one-way valve hydraulic fluid channel and bypass channel. Due to the large fluid flow area, no throttling effect occurs, thus avoiding over-buffering by the buffer device. Furthermore, because the moving parts of the hydraulic cylinder move at a relatively slow speed at this time, a smooth soft landing can still be maintained even if the buffer device does not create throttling.

[0024] The specific working principle of this buffer device varies depending on its location:

[0025] Scenario 1: If the hydraulic cylinder moving parts reciprocate up and down and the check valve assembly is located above the moving parts, the free-moving seal is in contact with the check valve cover under gravity, and the check valve is normally open. If the hydraulic cylinder moving parts move quickly, when they move upwards and approach the check valve assembly, they push the free-moving seal towards the check valve seat. This causes the minimum flow area of ​​the inverted cone formed between the check valve seat and the free-moving seal to be smaller than the hydraulic fluid passage area of ​​the check valve, thus creating a throttling effect. According to Bernoulli's principle, the fluid kinetic energy increases and the pressure energy decreases at the minimum flow area of ​​the inverted cone formed between the check valve seat and the free-moving seal. The resulting pressure difference overcomes the gravity of the free-moving seal and pulls it to the check valve seat, closing the check valve. At this point, the fluid medium in the hydraulic chamber can only flow out through the bypass channel, significantly reducing the outflow velocity. Therefore, the speed of the moving parts in the hydraulic cylinder decreases rapidly, ultimately achieving a soft landing. If the moving parts of the hydraulic cylinder move slowly, and the fluid velocity at the minimum flow area formed by the one-way valve seat and the free-moving seal is low, according to Bernoulli's principle, the pressure difference generated at this area is insufficient to overcome the gravity of the free-moving seal. Therefore, the one-way valve remains open. At this time, the fluid medium in the hydraulic chamber flows out through the hydraulic fluid channel and bypass channel of the one-way valve. Due to the large fluid flow area, no throttling effect occurs, thus avoiding over-buffering by the buffer device. Furthermore, because the moving parts of the hydraulic cylinder move slowly at this time, even without throttling by the buffer device, a smooth soft landing can still be maintained.

[0026] Scenario 2: If the hydraulic cylinder moving parts perform horizontal or oblique reciprocating motion, and the free-moving seal cannot maintain the check valve in a normally open state due to gravity alone, a spring is added between the free-moving seal and the check valve seat in the check valve assembly. In this case, the free-moving seal is in contact with the check valve cover under the spring force, and the check valve is in a normally open state. When the hydraulic cylinder moving parts move faster, and throttling occurs at the inverted conical minimum flow area formed between the check valve seat and the free-moving seal, according to Bernoulli's principle, the fluid kinetic energy at the inverted conical minimum flow area increases, and the pressure energy decreases. The resulting pressure difference overcomes the spring force of the free-moving seal and pulls it to the check valve seat, causing the check valve to close. At this point, the fluid medium in the hydraulic chamber can only flow out through the bypass channel, significantly reducing the outflow velocity. Therefore, the speed of the moving parts in the hydraulic cylinder decreases rapidly, ultimately achieving a soft landing. When the moving parts of the hydraulic cylinder move slowly, and the fluid velocity at the minimum flow area formed by the one-way valve seat and the free-moving seal is low, according to Bernoulli's principle, the pressure difference generated at this minimum flow area is insufficient to overcome the spring force of the free-moving seal. Therefore, the one-way valve remains open. At this time, the fluid medium in the hydraulic chamber flows out through the hydraulic fluid channel and bypass channel of the one-way valve. Due to the large fluid flow area, no throttling effect occurs, thus avoiding over-buffering by the buffer device. Furthermore, because the moving parts of the hydraulic cylinder move slowly at this time, even without throttling by the buffer device, a smooth soft landing can still be maintained.

[0027] Compared with the prior art, the beneficial effects of the present invention are:

[0028] (1) This invention controls the opening and closing state of the check valve assembly by providing a freely movable sealing body that can move flexibly. Only when the hydraulic cylinder moving part moves to the position close to the end of the check valve assembly, the freely movable sealing body is subjected to the combined action of the hydraulic cylinder moving part and the hydraulic oil to contact the check valve seat and form a seal. At this time, the check valve is closed, forming a throttling effect. At other times, the hydraulic cylinder maintains the maximum flow area. Therefore, this invention ensures that the fluid medium has a reasonable flow area during the movement of the hydraulic cylinder moving part, reduces energy consumption, and produces a more ideal throttling effect at the end of the hydraulic cylinder moving part's fall process, allowing the hydraulic cylinder moving part to land smoothly and softly.

[0029] (2) The opening and closing times of the one-way valve in this invention are determined by the movement speed of the free-moving seal and the flow rate of the fluid. The faster the hydraulic cylinder moves, the greater the flow rate of the fluid and the initial velocity of the free-moving seal. Therefore, the free-moving seal cooperates with the one-way valve seat to form a seal more quickly, and the one-way valve closes earlier. When the hydraulic cylinder moves slowly, the flow rate of the fluid and the initial velocity of the free-moving seal are smaller. Therefore, the free-moving seal cooperates with the one-way valve seat to form a seal later, and the one-way valve closes later or not at all. Therefore, this invention can achieve adaptive adjustment of the buffer opening time and buffer duration, which not only reduces energy consumption but also avoids the contradictory problems between the hydraulic cylinder stopping lag and the impact of the hydraulic cylinder moving parts in the existing hydraulic cylinder buffer mechanism.

[0030] (3) In this invention, a boss is added to the center of one side of the check valve assembly of the hydraulic cylinder moving part, and a recessed structure is provided at the center of the boss. The boss structure allows the hydraulic cylinder moving part to contact the free-moving seal earlier, thereby enabling the device to start throttling earlier. The recessed structure increases the contact area between the hydraulic cylinder moving part and the free-moving seal, making the contact between the end of the hydraulic cylinder moving part and the free-moving seal more stable. In addition, the hydraulic cylinder moving part has a hollow structure inside to reduce its mass and improve its frequency response characteristics.

[0031] (4) By adding a spring between the free-moving sealing body and the one-way valve seat, the present invention can enable normal use when the hydraulic cylinder is not perpendicular to the ground, and has a wide range of applicable scenarios.

[0032] (5) By designing the bypass channel as a variable area channel, the flow area of ​​the bypass channel gradually decreases as the hydraulic cylinder moving part moves closer to the one-way valve assembly during the movement of the one-way valve seat, and the throttling effect becomes stronger and stronger. The increasing throttling effect generated by the bypass channel greatly reduces the speed of the hydraulic cylinder moving part, and finally achieves a smoother soft landing. Attached Figure Description

[0033] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0034] Figure 1 , Figure 2 This is a schematic diagram of a valve seating buffer device for a hydraulic variable valve mechanism according to Embodiment 1 of the present invention.

[0035] Figure 3 This is a cross-sectional view of the valve opening stage in Example 1.

[0036] Figure 4 This is a cross-sectional view of the hydraulic piston contacting the free-moving seal during the valve fall-back stage in Example 1.

[0037] Figure 5 This is a cross-sectional view of the valve retraction phase in Example 1, where the freely movable seal is adsorbed by the one-way valve seat.

[0038] Figure 6 This is a schematic diagram of the inverted conical minimum flow area formed between the one-way valve seat and the free-moving seal body in Example 1.

[0039] Figure 7 This is a buffer device for a plunger-type hydraulic cylinder, as described in Example 2.

[0040] Figure label:

[0041] 1. One-way valve assembly; 1-1. Free-moving sealing body; 1-2. One-way valve cover; 1-3. One-way valve seat;

[0042] 2. Hydraulic piston; 2-1. Piston body; 2-2. Piston plug;

[0043] 3. Fluid passage; 3-1. Check valve hydraulic fluid passage; 3-2. Bypass passage;

[0044] 4. Cylinder liner. Detailed Implementation

[0045] To make the technical problems, technical solutions and advantages of the present invention clearer, a detailed description will be given below in conjunction with the accompanying drawings and specific embodiments.

[0046] Example 1

[0047] This embodiment provides a valve seating buffer device for a hydraulic variable valve mechanism. The invention uses a freely movable seal in a one-way valve assembly as a control element to control the opening and closing of the hydraulic fluid passage of the one-way valve, thereby achieving a variable hydraulic flow area for the buffer device. This reduces the impact on the moving parts of the hydraulic cylinder at the end of their movement and ensures that the moving parts reach the end position in a timely manner. The opening and closing timing of the hydraulic fluid passage of the one-way valve in this invention is variable according to the moving speed of the hydraulic cylinder parts and the fluid flow rate, and the structure is simple, thus meeting the buffering requirements of the hydraulic cylinder parts under varying operating conditions. This invention solves the contradictory problem between hydraulic cylinder stopping lag and hydraulic cylinder impact in the prior art, and is of great significance for improving the safety of reciprocating hydraulic cylinders. Specifically, as shown... Figures 1 to 4 As shown, it includes a one-way valve assembly 1, a hydraulic piston 2, a fluid passage 3, and a cylinder liner 4; the valve assembly is prior art, including a valve and a valve spring, and will not be described in detail.

[0048] The one-way valve assembly 1 includes a freely movable sealing body 1-1, a one-way valve cover 1-2, and a one-way valve seat 1-3. The one-way valve seat has a one-way valve hydraulic fluid passage 3-1. The freely movable sealing body 1-1 can move between the one-way valve seat 1-3 and the one-way valve cover 1-2. When the freely movable sealing body 1-1 is located on the one-way valve cover 1-2, the minimum flow area of ​​the inverted cone formed between the freely movable sealing body 1-1 and the one-way valve seat 1-3 is greater than the area of ​​the one-way valve hydraulic fluid passage 3-1. When the freely movable sealing body 1-1 contacts the one-way valve seat 1-3 to form a seal, the one-way valve is in the closed state; otherwise, it is in the open state.

[0049] Specifically, when the free-moving seal is located on the one-way valve cover, an inverted conical flow channel is formed between the free-moving seal and the one-way valve seat. This inverted conical flow channel has a minimum flow area, such as... Figure 7 As shown, the inverted cone-shaped flow area is smallest at the point where the center of the bottom fillet of the hydraulic fluid passage of the check valve is located and the center of the free-moving seal. Ignoring the radius of the fillet of the hydraulic fluid passage of the check valve, this inverted cone-shaped minimum flow area... The area of ​​the minimum flow channel in the inverted cone shape Larger than the area of ​​the hydraulic fluid passage of the check valve ;

[0050] Where L is the distance from the free-moving seal to the one-way valve seat; r is the radius of the hydraulic fluid passage of the one-way valve; and R is the radius of the free-moving seal.

[0051] When the moving parts of the hydraulic cylinder move close to the one-way valve assembly within the cylinder liner, they push the free-moving seal body towards the one-way valve seat, reducing the distance L between the free-moving seal body and the one-way valve seat. Less than At this time, a throttling effect is formed at the minimum flow area of ​​the inverted cone.

[0052] Furthermore, in this embodiment, to enable the piston body 2-1 to push the free-moving seal body, a countersunk through hole matching the free-moving seal body is provided at the center of the one-way valve cover. The diameter of this through hole is smaller than the diameter of the free-moving seal body, and the diameter of the countersunk hole is larger than the diameter of the free-moving seal body, allowing the free-moving seal body to be embedded in the piston cavity, such as... Figure 1 As shown.

[0053] Furthermore, in this embodiment, the hydraulic piston 2 includes a piston body 2-1 and a plug 2-2 with a raised structure on the top. The piston body 2-1 has a hollow internal structure to reduce its mass. The hole drilled on the top of the hydraulic piston is plugged by the plug 2-2. The center of the protruding part of the plug has a spherical recess to increase the contact area with the free-moving seal. When the hydraulic piston moves towards the one-way valve seat, the protruding part of the plug 2-2 will push up the free-moving seal 1-1 inside the one-way valve, causing it to move towards the one-way valve seat.

[0054] Fluid passage 3 includes a one-way valve hydraulic fluid passage 3-1 and a bypass passage 3-2. This device is connected to an external hydraulic system via the one-way valve hydraulic fluid passage 3-1 and the bypass passage 3-2. The bypass passage 3-2 is equipped with a variable throttling channel, which is formed by the outer circumferential side of the piston body 2-1 and the side U-shaped hole on the cylinder liner 4. The bypass passage 3-2 with its variable throttling channel and the one-way valve hydraulic fluid passage 3-1 are interconnected with the external hydraulic system.

[0055] Cylinder liner 4 serves as a support and guide, and a U-shaped bypass channel 3-2 is provided on the side of the cylinder liner.

[0056] In this embodiment, the hydraulic piston 2 of the valve seating buffer device of a hydraulic variable valve mechanism drives the valve movement, and the hydraulic piston is driven by hydraulic oil. In this device, the one-way valve assembly is installed on the top of the cylinder liner, and a free-moving seal 1-1 is used as the control element. The cross-sectional shape of the fluid passage between the free-moving seal 1-1 and the one-way valve seat 1-3 is an inverted cone, and its cross-sectional area changes with the position of the free-moving seal 1-1. During the valve opening stage, the one-way valve is normally open, and hydraulic oil flows in through the one-way valve hydraulic fluid passage 3-1 and the bypass passage 3-2, causing the hydraulic piston to move downward. During the valve retraction stage, the hydraulic oil first flows out through the one-way valve hydraulic fluid passage 3-1 and the bypass passage 3-2. When the free-moving seal 1-1 contacts and is absorbed by the one-way valve seat 1-3, the one-way valve hydraulic fluid passage 3-1 closes. At this time, the remaining hydraulic oil in the piston chamber can only flow out through the bypass passage 3-2. The resulting strong throttling effect causes the hydraulic piston speed to decrease rapidly, ultimately achieving a soft landing of the valve.

[0057] The specific working process of this embodiment is as follows:

[0058] In such Figure 2During the valve opening phase, as shown, hydraulic oil enters the piston chamber from the external hydraulic system through the check valve hydraulic fluid passage 3-1 and the bypass passage 3-2. The free-moving seal 1-1, under the influence of gravity and oil pressure, contacts the check valve cover, at which point the check valve is open. As the piston moves downward, the oil flow rate through the bypass passage 3-2 gradually increases to its maximum. At this point, the flow area of ​​the hydraulic oil flowing into the piston chamber is the sum of the flow area of ​​the bypass passage and the flow area of ​​the check valve hydraulic fluid passage.

[0059] During the valve retraction phase, hydraulic oil flows out through bypass channel 3-2 and check valve hydraulic fluid channel 3-1, and the hydraulic piston begins to move upward. As the hydraulic piston 2 moves upward, it approaches the check valve cover 1-2, pushing the free-moving seal 1-1 towards the check valve seat 1-3. This causes the minimum flow area of ​​the inverted cone formed between the check valve seat 1-3 and the free-moving seal 1-1 to be smaller than the area of ​​the check valve hydraulic fluid channel 3-1, creating a throttling effect. Figure 3 As shown. When the hydraulic piston 2 moves faster, and the fluid velocity at the inverted conical minimum flow area formed between the one-way valve seat 1-3 and the free-moving seal 1-1 is higher, according to Bernoulli's principle, the kinetic energy of the fluid at the inverted conical minimum flow area between the one-way valve seat 1-3 and the free-moving seal 1-1 increases, and the pressure energy decreases. The resulting pressure difference will overcome the gravity of the free-moving seal 1-1 and attract it to the one-way valve seat 1-3, causing the one-way valve to close. Figure 4 As shown. At this time, the hydraulic oil in the piston chamber can only flow out through the bypass channel 3-2. The fluid outflow velocity inside the piston chamber is significantly reduced, so the speed of the hydraulic piston 2 decreases rapidly, ultimately achieving a soft landing. When the hydraulic piston 2 moves slowly, and the fluid velocity at the inverted conical minimum flow area formed between the one-way valve seat 1-3 and the free-moving seal 1-1 is low, according to Bernoulli's principle, the pressure difference generated at the inverted conical minimum flow area formed between the one-way valve seat 1-3 and the free-moving seal 1-1 is insufficient to overcome the gravity of the free-moving seal, so the one-way valve remains open. At this time, the hydraulic oil flows out through the hydraulic fluid channel 3-1 and the bypass channel 3-2 of the one-way valve. Due to the large fluid flow area, no throttling effect occurs, thus avoiding the situation where the buffer device over-buffers and the valve fails to seat. Furthermore, because the hydraulic piston 2 moves slowly at this time, even if the buffer device does not form a throttling effect, a smooth soft landing can still be maintained.

[0060] Example 2

[0061] The valve seating buffer device for a hydraulic variable valve mechanism disclosed in Embodiment 1 is only applicable to situations where the hydraulic piston reciprocates up and down and the one-way valve assembly is located on top of the hydraulic piston, thus limiting its application scenarios. Therefore, this embodiment proposes a buffer device for a plunger-type hydraulic cylinder, which has a wider range of applications and can be used in situations such as when the hydraulic cylinder moving parts reciprocate up and down and the one-way valve is located at the top of the hydraulic cylinder moving parts, when the hydraulic cylinder moving parts reciprocate up and down and the one-way valve is located at the bottom of the hydraulic cylinder moving parts, and when the hydraulic cylinder moving parts reciprocate linearly in the horizontal direction.

[0062] like Figure 6 As shown, this embodiment differs from Embodiment 1, mainly in the following aspects:

[0063] (1) In the one-way valve assembly, a spring 1-4 is added between the free-moving sealing body 1-1 and the one-way valve seat 1-3.

[0064] (2) The buffer device of a plunger-type hydraulic cylinder in this embodiment is placed horizontally.

[0065] The specific working process of this embodiment is as follows:

[0066] During the piston's rightward opening phase, hydraulic oil enters the piston chamber through hydraulic fluid passage 3-1 and the bypass passage. The free-moving seal 1-1, under the action of spring force and oil pressure, contacts the check valve cover, at which point the check valve is in the open state. The flow area of ​​the hydraulic oil flowing into the piston chamber is the sum of the flow area of ​​the bypass passage and the flow area of ​​the check valve's hydraulic fluid passage 3-1.

[0067] During the leftward retraction phase of the plunger, hydraulic oil first flows out through the bypass channel and the hydraulic fluid passage 3-1 of the check valve, and hydraulic plunger 2 begins to move to the left. During this leftward movement, hydraulic plunger 2 moves close to the check valve cover 1-2, pushing the free-moving seal 1-1 towards the check valve seat 1-3. This causes the inverted conical minimum flow area formed between the check valve seat 1-3 and the free-moving seal 1-1 to be smaller than the area of ​​the hydraulic fluid passage 3-1 of the check valve, creating a throttling effect. When hydraulic plunger 2 moves faster, and the fluid velocity at the inverted conical minimum flow area formed between the check valve seat 1-3 and the free-moving seal 1-1 is higher, according to Bernoulli's principle, the kinetic energy of the fluid at this area increases, and the pressure energy decreases. The resulting pressure difference overcomes the spring force of the free-moving seal 1-1, drawing it to the check valve seat 1-3, thus closing the check valve. At this point, the hydraulic oil in the piston chamber can only flow out through the bypass channel, significantly reducing the fluid outflow velocity inside the piston chamber. Therefore, the speed of hydraulic piston 2 decreases rapidly, ultimately achieving a soft landing. When the hydraulic plunger 2 moves slowly, and the fluid velocity at the inverted conical minimum flow area formed between the one-way valve seat 1-3 and the free-moving seal 1-1 is low, according to Bernoulli's principle, the pressure difference generated at this area is insufficient to overcome the spring force of the free-moving seal. Therefore, the one-way valve remains open. At this time, the hydraulic oil flows out through the hydraulic fluid channel 3-1 and the bypass channel of the one-way valve. Due to the large fluid flow area, no throttling effect occurs, thus avoiding over-buffering by the buffer device. Furthermore, because the hydraulic plunger 2 moves slowly at this time, even without throttling by the buffer device, a smooth soft landing can still be maintained.

[0068] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A buffer device for a linear reciprocating hydraulic cylinder, characterized in that, Includes a one-way valve assembly, hydraulic cylinder moving parts, and cylinder liners; wherein: A one-way valve assembly includes a one-way valve seat, a one-way valve cover, and a free-moving seal. The one-way valve seat has a hydraulic fluid passage for the one-way valve. When the free-moving seal is located on the one-way valve seat, the free-moving seal and the one-way valve seat form a seal, at which point the one-way valve is closed. When the free-moving seal is located on the one-way valve cover, an inverted conical minimum flow area is formed between the free-moving seal and the one-way valve seat. This inverted conical minimum flow area is larger than the area of ​​the hydraulic fluid passage for the one-way valve. The cylinder liner provides support and guidance for the moving parts of the hydraulic cylinder. One end of the cylinder liner is connected to the one-way valve cover. The hydraulic cylinder moving parts reciprocate linearly within the cylinder liner. When the hydraulic cylinder moving parts move close to the one-way valve assembly, they push the free-moving seal body towards the one-way valve seat, so that the minimum flow area of ​​the inverted cone formed between the one-way valve seat and the free-moving seal body is smaller than the hydraulic fluid passage area of ​​the one-way valve. The cylinder liner, the end face of the moving part of the hydraulic cylinder, and the one-way valve cover constitute the hydraulic chamber of the moving part of the hydraulic cylinder, and a bypass channel communicating with the hydraulic chamber is provided on the cylinder liner. The hydraulic cylinder moving part has a recessed structure at the center of the end near the one-way valve assembly, and the shape of the recessed structure matches the surface shape of the free-moving seal. The central circular recess structure is set on a protrusion with a certain height.

2. The buffer device for a linear reciprocating hydraulic cylinder according to claim 1, characterized in that, The inverted conical minimum flow area is greater than the area of ​​the hydraulic fluid passage of the check valve; where L is the distance from the free-moving seal to the check valve seat; r is the radius of the hydraulic fluid passage of the check valve; and R is the radius of the free-moving seal.

3. The buffer device for a linear reciprocating hydraulic cylinder according to claim 1, characterized in that, In the one-way valve assembly, a spring is added between the free-moving sealing body and the one-way valve seat.

4. The buffer device for the linear reciprocating hydraulic cylinder according to claim 1, characterized in that, The bypass channel may be one or more; the flow area of ​​the bypass channel may be fixed or variable.

5. The buffer device for a linear reciprocating hydraulic cylinder according to claim 4, characterized in that, The variable throttling channel is achieved by a U-shaped bypass channel set on the cylinder liner. The U-shaped groove on the side of the cylinder liner is gradually covered or gradually opened as the hydraulic cylinder moves.

6. The buffer device for a linear reciprocating hydraulic cylinder according to claim 1, characterized in that, The free-moving sealing body in the one-way valve assembly is a rotating body.

7. The buffer device for a linear reciprocating hydraulic cylinder according to claim 1, characterized in that, A countersunk through hole matching the free-moving seal body is provided at the center of the one-way valve cover. The diameter of the through hole is smaller than the diameter of the free-moving seal body, while the diameter of the countersunk hole is larger than the diameter of the free-moving seal body.

8. The buffer device for a linear reciprocating hydraulic cylinder according to claim 1, characterized in that, The moving parts of the hydraulic cylinder have a hollow structure inside.

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