Built-in hydraulic damping buffer actuator

Abstract

This invention discloses a built-in hydraulic damping buffer actuator, belonging to the field of hydraulic actuators. This invention can be achieved through the following technical solution: The hydraulic damping buffer uses two stages of buffer cylinder heads connected in series in an axially recursive manner from small to large, dividing the space into two stages of buffer chambers with progressively larger working volumes. The first stage is the primary buffer chamber and also serves as the oil discharge chamber, while the second stage is the main buffer chamber, with the two stages recursively increasing in size. When the piston rod retracts almost to the bottom, the first and second stage buffer cylinder heads, under the action of the bottom structure of the hydraulic piston cylinder, contract towards the bottom, causing the oil in the first stage primary buffer chamber to be squeezed, forming a buffering pressure. At this time, the oil in the buffer chamber can only be discharged through the annular gap. Controlling the size of the annular gap slows down the oil discharge speed from the buffer chamber, creating a certain resistance, thereby reducing the final speed of the piston rod retracting, achieving the buffering effect at the end of the actuator's retraction position.

Description

Technical Field

[0001] This invention belongs to the field of hydraulic actuators and mechanical equipment damping buffers (or shock absorbers), and relates to a hydraulic actuator with retractable end damping function, mainly used in hydraulic system actuators of industries such as aviation, aerospace, ships, vehicles, large engineering equipment series buffers, building series buffers, and bridge series buffers. Background Technology

[0002] In hydraulic and pneumatic transmission systems, the power of an actuator is transmitted and controlled through pressurized liquid or gas within a closed circuit. Actuators typically use either liquid or gas as their working medium and are a common type of actuator in hydraulic and pneumatic transmission systems. They are generally classified into two types: reciprocating linear actuators and reciprocating oscillating actuators. They are devices that convert pneumatic or hydraulic power into mechanical force and motion. When an actuator drives a large moving part at a high speed, the inertia of the moving part is significant. When the piston / piston rod of the actuator reaches its limit position, impacts and noise caused by mechanical collisions can easily occur. The piston rod is the connecting component that supports the piston's work and is used in the moving parts of actuator cylinders and pneumatic cylinders. It is a moving component with frequent movement and high technical requirements. Taking a hydraulic cylinder as an example, it consists of a cylinder barrel, piston rod, piston, and end cap. The piston rod is a slender shaft part with strict requirements for coaxiality. When using a piston rod, it must withstand alternating loads, directly affecting the lifespan and reliability of the entire product. When a hydraulic cylinder drives a heavy, fast-moving working part, a buffer device is generally required. The purpose is to eliminate the mechanical impact between the piston and cylinder head caused by the inertial force and hydraulic pressure of the moving parts, and also to reduce the noise of the fluid when the piston changes direction. At the end of the piston stroke, if the piston does not buffer and decelerate, it exerts a large impact force on the cylinder head, causing a collision. In severe cases, the piston may violently strike the cylinder head, damaging it and causing the hydraulic cylinder base to break.

[0003] As is well known, damping refers to the various frictions and other obstacles that attenuate free vibrations. Damping is one of the three fundamental elements for controlling vibration. A damper is a device used to mitigate and withstand external impacts, playing a crucial role in industrial automation equipment. A "special" component placed on a structural system that provides resistance to motion and reduces kinetic energy is called a damping damper. Damped hydraulic dampers are also known as "energy-dissipating dampers." There are many types of hydraulic dampers; based on the arrangement of the drain hole, they can be divided into hydraulic dampers with drain holes on the plunger and hydraulic dampers with overflow holes on the inner wall of the cylinder. Because the actuator of a mechanical device has a buffer mechanism at the end of its stroke inside the hydraulic cylinder, the piston component driving the load can be decelerated when it reaches the end of its stroke, reducing the mechanical impact between the piston and the end cap caused by the inertial force and hydraulic pressure of the piston component. Therefore, the end-stroke buffer mechanism of a hydraulic cylinder usually adopts an energy-buffering method, which seals the hydraulic oil in the low-pressure chamber of the hydraulic cylinder that is finally discharged back to the oil tank, allowing it to flow out through a throttling orifice or gap, thus achieving the purpose of deceleration. Simultaneously, the fluid within the buffer chamber generates internal pressure, which can resist the effects of inertial forces and other external forces to achieve buffering. Its energy conversion mechanism is to convert kinetic energy into heat energy, which is then carried out of the hydraulic cylinder by the circulating fluid.

[0004] Hydraulic dampers are common mechanical devices in modern machinery, typically used to absorb the impact of rotational or linear motion, reduce vibration and noise, and protect equipment. Whether the strength of a hydraulic damper is adjustable depends on its type. Currently, the most commonly used hydraulic dampers on the market include adjustable and non-adjustable dampers, and the actual effect of adjusting their strength differs between the two. Adjustable dampers, whose strength is not adjustable, maintain linear deceleration of the moving workpiece through specifically designed oil ports and distribution methods. They can absorb energy without adjustment from high speed and light load to low speed and heavy load. The two most common types of industrial dampers, hydraulic dampers and hydraulic-pneumatic combined dampers, while simple in structure and easy to design and manufacture, and able to smoothly and quietly stop moving parts with relatively small force during their buffering stroke, also have disadvantages such as insufficient buffering effect, slow impact dissipation, and large recoil force. Therefore, at the end of the stroke, very large resistance and rebound force are inevitably generated. Other types, such as dampers, due to the lack of a carefully designed oil port system, will generate a large impact force at the beginning of the buffering stroke. When all hydraulic dampers are impacted, the piston rod moves inward, forcing hydraulic oil to flow into the accumulator through the oil hole, thus generating a resistance force.

[0005] Currently, buffer mechanisms generally come in various structural forms, including orifice throttling, annular slot throttling, or a combination of orifices and annular slots. Orifice throttling achieves throttling by blocking the free flow of fluid through a small orifice and is commonly used for full-range buffering. Based on whether the flow area of ​​the throttling orifice or slot changes automatically during the buffering process, they can be broadly classified into constant throttling area buffer devices and variable throttling area buffer devices. The characteristic of constant throttling area buffer devices is that the throttling area remains constant during the buffering process. At the beginning of buffering, a relatively large buffering pressure can be generated, but it quickly decreases, resulting in a generally poor buffering effect. In contrast, with variable throttling area buffer devices, the flow area of ​​the throttling orifice or slot changes automatically with the buffering stroke, keeping the buffering pressure in the buffer oil chamber relatively uniform or exhibiting a certain regular variation. However, this type of buffering effect may not be ideal. At the end of the stroke, very large resistance and rebound forces may inevitably occur. Other devices, such as dampers, due to the lack of a carefully designed oil hole system, can generate a large impact force at the beginning of the buffering stroke. Annular slot throttling achieves flow restriction by creating a circumferential slot through a clearance fit between the cylinder and shaft, thus hindering fluid flow. It is commonly used for end-stage buffering. The small clearance between the cylinder and shaft in an annular slot throttling system necessitates high machining precision, making it difficult to manufacture. Due to the limitations of machining precision, there is a high probability of misalignment between the cylinder and shaft after assembly, leading to difficulties in adjustment and poor performance consistency. While it offers advantages such as simple structure and ease of design and manufacturing, it also suffers from drawbacks such as insufficient buffering effect, slow disappearance of impact phenomena, and high recoil force. Summary of the Invention

[0006] The purpose of this invention is to address the problems existing in the prior art by providing a hydraulic actuator with a compact structure, rapid disappearance of impact phenomena, small recoil, no obvious threshold, excellent energy dissipation effect, stable performance, long service life, and convenient servo control. This actuator can improve the motion efficiency and accuracy of equipment, especially with a gap throttling and retraction end-buffering function. The initial force is relatively small, resulting in low cost. The above-mentioned objective of the present invention can be achieved by the following technical solution: a built-in hydraulic damping buffer actuator, comprising: a hydraulic piston cylinder 7 within the working chamber of the actuator body, and a piston rod 8 reciprocating within the hydraulic piston cylinder 7 and directly performing work externally, characterized in that: the piston rod 8 is a hollow rod body separated by a partition wall, and the tail end of the hollow rod body is provided with a buffer piston that divides the hydraulic piston cylinder 7 into a hydraulic chamber and a stroke chamber. The buffer piston ring is sealed within the hydraulic piston cylinder 7 and operates within the hydraulic piston cylinder 7, and is provided with a hydraulic damping buffer that uses hydraulic damping to buffer and decelerate the piston rod 8 to a stop. The hydraulic damping buffer uses at least two stages of buffer cylinder heads that are axially recursively connected in ascending order of size, dividing the space into at least two stages of buffer chambers with progressively larger working volumes, thereby preventing or reducing the impact caused by inertial forces when the piston rod 8 moves to its two ends. The impact is caused by a multi-stage telescopic buffer chamber. The first stage is the primary buffer chamber and also serves as the oil discharge chamber. The second stage is the main buffer chamber, and the two stages of buffer chambers are axially recursively arranged from small to large. During the retraction movement of the piston rod 8, the hydraulic oil transmits the piston's thrust to the two-stage buffer cylinder heads. The first-stage buffer cylinder head 10 comes into contact with the hydraulic piston cylinder 7. When the piston is about to reach the end of its stroke, the two-stage buffer chambers are squeezed by the two-stage buffer cylinder heads respectively, and the buffer pressure in the oil discharge chamber increases. This forces the hydraulic oil to return through the buffer ring gap 9 on the outer circle of the first-stage buffer cylinder head 10 and flow out of the buffer chamber, forming a buffer pressure. The piston rod 8 slows down at the end of its stroke, linearly decelerating. The hydraulic damping buffer stops the piston rod 8 smoothly and quietly with a small force. The impact stroke ends, and the buffer structure automatically resets, waiting for the next impact to reverse and extend the piston rod 8.

[0007] Compared with the prior art, the present invention has the following beneficial effects.

[0008] This invention employs at least two stages of buffer cylinder heads, recursively connected axially from small to large, dividing the space into at least two stages of buffer chambers with increasing working volumes. This forms a multi-stage telescopic buffer chamber pressure to prevent or reduce the impact caused by inertial forces when the piston rod 8 moves to its two ends. The structure is compact and reasonable, with good sealing, reliable operation, fast dynamic response, and rapid elimination of impact phenomena. These buffer chambers, with their gradually increasing volumes, can gradually shrink as the buffer stroke increases, while the buffer pressure increases, achieving a relatively stable buffering effect. Compared to other damping buffers, this type also saves space.

[0009] This invention comprises a first-stage buffer cylinder head 10, a second-stage buffer cylinder head 5, and a bushing 2, which, through structural design, encapsulate a first-stage buffer cavity 3 and a second-stage buffer cavity 4 within the piston rod 8, forming a multi-stage buffer cavity. This effectively eliminates the impact vibration generated by the rapid movement of the actuator piston, ensuring smooth operation. Due to the damping effect of the annular gap's spring damper, the kinetic energy of the moving body is converted into throttling heat from the damper. This allows the buffer pressure within the cylinder to remain constant during the buffering process, thereby achieving uniform deceleration buffering. Not only is the backlash small and without a significant threshold, resulting in excellent buffering effect, but it also exhibits low hydraulic shock, smooth operation, and excellent energy dissipation.

[0010] The first-stage buffer cylinder head 10, the second-stage buffer cylinder head 5, and the bushing 2 of this invention, through structural design, encapsulate a first-stage buffer cavity 3 and a second-stage buffer cavity 4 within the piston rod 8, forming a short-stroke buffer cavity. This allows for a smooth and quiet stop of the moving parts with minimal force during its buffering stroke. By precisely controlling the movement speed and reducing vibration and impact forces, the service life, operating efficiency, and precision of the equipment are improved.

[0011] This invention employs a first-stage primary buffer chamber that also serves as an oil discharge chamber, and a second-stage primary buffer chamber, with the two buffer chambers recursively increasing in size axially. This effectively reduces vibration and impact forces generated during high-speed operation, preventing wear and damage to equipment components and extending the equipment's service life. The hydraulic damping buffer structure converts the kinetic energy of the piston rod 8 into the heat energy of the hydraulic oil in the buffer section, which is then carried out of the pressure cylinder by the oil flow, effectively reducing the impact and vibration on the equipment and solving the problem of large impact loads caused by excessively high actuator speeds.

[0012] All components of the actuator in this invention are mechanically connected, ensuring high reliability. It features a compact structure, small size, fast response speed, and no special limitations, making it widely applicable to hydraulic equipment requiring damping. Attached Figure Description

[0013] Figure 1 This is a full sectional view of the retracted end damping buffer mechanism of the built-in hydraulic damping buffer actuator of the present invention when there is no buffering. Figure 2 yes Figure 1 A sectional view; In the diagram: 1-Return spring, 2-Bushing, 3-First-stage buffer chamber, 4-Second-stage buffer chamber, 5-Second-stage buffer cylinder head, 6-Return spring, 7-Hydraulic piston cylinder, 8-Piston rod, 9-Annular gap, 10-First-stage buffer cylinder head.

[0014] The present invention will be further described below with reference to the accompanying drawings and embodiments, but this does not limit the invention to the scope of the described embodiments. All these concepts should be considered as the content disclosed in this technology and the scope of protection of this patent. Detailed Implementation

[0015] See Figure 1 In the illustrative preferred embodiment described below, a built-in hydraulic damping buffer actuator includes: a hydraulic piston cylinder 7 within the working chamber of the actuator body, and a piston rod 8 that reciprocates within the hydraulic piston cylinder 7 and directly performs work externally. The piston rod 8 is a hollow rod separated by a partition wall. At the tail end of the hollow rod, a buffer piston is provided, dividing the hydraulic piston cylinder 7 into a hydraulic chamber and a stroke chamber. This buffer piston ring is sealed within the hydraulic piston cylinder 7 and operates within it. A hydraulic damping buffer is also provided to buffer and decelerate the piston rod 8 to a stop using hydraulic damping. This hydraulic damping buffer employs at least two stages of buffer cylinder heads that are axially recursively connected in ascending order of size, dividing the space into at least two stages of buffer chambers with progressively larger working volumes. This forms a multi-stage telescopic buffer chamber pressure to prevent or reduce the impact caused by inertial force when the piston rod 8 reaches its two ends. The first stage is a primary buffer chamber and also serves as an oil discharge chamber, the second stage is the main buffer chamber, and the two stages of buffer chambers... The movement proceeds axially from small to large. During the retraction motion of the piston rod 8, the hydraulic oil transmits the piston's thrust to the two-stage buffer cylinder head. The first-stage buffer cylinder head 10 contacts the hydraulic piston cylinder 7 at the bottom. As the piston approaches the end of its stroke, the two-stage buffer chambers are squeezed by the two-stage buffer cylinder heads, increasing the buffer pressure in the discharge chamber. This forces the hydraulic oil to return through the gap 9 of the outer ring of the first-stage buffer cylinder head 10 and flow out of the buffer chamber, forming a buffer pressure. The piston rod 8's end stroke speed decreases and slows down, resulting in linear deceleration. The hydraulic damping buffer smoothly and quietly stops the piston rod 8 with a small force. The impact stroke ends, and the buffer structure automatically resets, waiting for the next impact to reverse and extend the piston rod 8.

[0016] The built-in hydraulic damping buffer includes: a return spring 6 constrained by a hollow stepped buffer plunger spring washer with a mountain-shaped cross-section of the first-stage buffer cylinder head 10, which is separated from the bottom of the spring cavity by the partition wall of the piston rod 8; a bushing 2 that is engaged with the corner of the flange ring of the second-stage buffer cylinder head 5 and forms the second-stage buffer cavity 4 with the end face of the stepped cavity of the piston bottom; a first-stage buffer cavity 3 formed by the second-stage buffer cylinder head 5 with a mountain-shaped cross-section stepped column washer constrained by the mountain-shaped cross-section of the first-stage buffer cylinder head 10 and sealed around the outer circle of the mountain-shaped cross-section; and a return spring 1 fitted on the buffer plunger with the central stepped cross-section of the mountain-shaped cross-section.

[0017] The function of the return spring 6 is to allow the piston to return to its original position after completing the buffering action. The return spring 1 plays a buffering and acceleration role between the buffer pad at the bottom of the first-stage buffer cylinder head 10 and the hydraulic piston cylinder 7, and ensures that it will not be damaged due to frequent impacts.

[0018] The bushing 2 and the second-stage buffer cylinder head 5 form an annular throttling gap 9 between their corner interlocking ring surfaces.

[0019] The bushing 2 has a flange ring on its annular surface that matches the stepped hole at the piston port.

[0020] The second-stage buffer cylinder head 5 is a cylinder head with a corner end ring.

[0021] The piston ring seals the piston cylinder 7. The ring surface has a groove for mounting the guide ring. The back end of the guide ring has a rounded transition protrusion. The bottom of the free end of the piston has a buffer ring groove.

[0022] The hydraulic piston cylinder 7 is equipped with a variable cross-section gradually rounded transition arc ring that matches the bushing 2 arc ring.

[0023] The first-stage buffer cylinder head 10, the second-stage buffer cylinder head 5, and the bushing 2 are structurally designed to form a first-stage buffer chamber 3 and a second-stage buffer chamber 4. The bushing 2 is connected to the second-stage buffer cylinder head 5 by a corner snap and is sealed inside the stepped hole of the piston rod 8 to form a multi-stage buffer chamber pressure.

[0024] When the piston rod 8 extends in the opposite direction, the first-stage buffer cylinder head 10 and the second-stage buffer cylinder head 5 extend slowly step by step under the action of the return spring 1 and the return spring 6. Oil from outside the buffer chamber is drawn into the first-stage buffer chamber 3 and the second-stage buffer chamber 4, which are sealed by the annular gap 9, and the buffer structure resets to meet the conditions for the next use.

[0025] The first-stage buffer cylinder head 10, the second-stage buffer cylinder head 5, and the bushing 2 are structurally designed to encapsulate the first-stage buffer chamber 3 and the second-stage buffer chamber 4 within the piston rod 8, forming a multi-stage buffer chamber pressure.

[0026] The first-stage buffer cylinder head 10, the second-stage buffer cylinder head 5, and the bushing 2 are encapsulated in the first-stage buffer chamber 3 and the second-stage buffer chamber 4 within the piston rod 8 through structural design, forming a short-stroke buffer. When the piston rod retracts, the buffer sleeve of the first-stage buffer cylinder head 10 moves to the left under the action of oil pressure, realizing rapid start-up when the piston rod of the hydraulic piston cylinder 7 retracts.

[0027] The first-stage buffer cylinder head 10, the second-stage buffer cylinder head 5, and the bushing 2 are structurally designed to encapsulate the first-stage buffer chamber 3 and the second-stage buffer chamber 4 within the piston rod 8, forming a multi-stage buffer chamber pressure.

[0028] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions, and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A built-in hydraulic damping buffer actuator, comprising: The hydraulic piston cylinder (7) is located within the working chamber of the actuator body. A piston rod (8) reciprocates within the hydraulic piston cylinder (7) and directly performs work externally. The piston rod (8) is characterized by being a hollow rod separated by a partition wall. At the tail end of the hollow rod, a buffer piston is provided that divides the hydraulic piston cylinder (7) into a hydraulic chamber and a stroke chamber. This buffer piston ring is sealed within the hydraulic piston cylinder (7) and operates within it. Furthermore, a hydraulic damping buffer is provided to buffer and decelerate the piston rod (8) to a stop using hydraulic damping. The built-in hydraulic damping buffer includes a first-stage buffer cylinder cover (10). A hollow stepped buffer plunger spring washer with a mountain-shaped cross-section is constrained by a return spring (6) at the bottom of the spring cavity separated by the partition wall of the piston rod (8); the bushing (2) is interlocked with the end flange ring of the second-stage buffer cylinder head (5) at the corner, and the bushing (2), the second-stage buffer cylinder head (5), and the end face of the stepped cavity of the piston bottom form the second-stage buffer cavity (4); the second-stage buffer cylinder head (5) is constrained by the stepped column washer with a mountain-shaped cross-section of the first-stage buffer cylinder head (10) and is circumferentially sealed on the outer circle of the mountain-shaped cross-section, and the second-stage buffer cylinder head (5) and the first-stage buffer cylinder head (10) form the first-stage buffer cavity (3), and so on. A return spring (1) is fitted on the buffer plunger of the center step of the mountain-shaped cross section of the first-stage buffer cylinder head (10); the hydraulic damping buffer adopts at least two stages of buffer cylinder heads that are axially recursively connected in ascending order, and is divided into at least two stages of buffer chambers with working volumes ranging from small to large, so as to form a multi-stage telescopic buffer chamber pressure to prevent or reduce the impact caused by the inertial force when the piston rod (8) moves to the end point. Among them, the first stage is the primary buffer chamber and serves as the oil discharge chamber, and the second stage is the main buffer chamber. The two stages of buffer chambers are axially recursively connected in ascending order. During the retraction movement of the piston rod (8), the first-stage buffer cylinder head (10) When the piston is about to reach the end of its stroke, the two-stage buffer chambers are squeezed by the two-stage buffer cylinder heads respectively, and the buffer pressure in the oil discharge chamber increases. This forces the hydraulic oil to flow out of the buffer chamber through the gap (9) of the outer circle buffer ring of the first-stage buffer cylinder head (10), forming a buffer pressure. The piston rod (8) at the end of its stroke moves slower and becomes linearly decelerated. The hydraulic damping buffer stops the piston rod (8) smoothly and quietly with a small force. The impact stroke ends, and the buffer structure automatically resets, waiting for the next impact to reverse and extend the piston rod (8).

2. The built-in hydraulic damping buffer actuator as described in claim 1, characterized in that: The function of the return spring (6) is to allow the piston to return to its original position after completing the buffering action. The return spring (1) plays a buffering role between the buffer pad at the bottom of the first-stage buffer cylinder head (10) and the hydraulic piston cylinder (7), and ensures that it will not be damaged due to frequent impacts.

3. The built-in hydraulic damping buffer actuator as described in claim 2, characterized in that: The second-stage buffer cylinder head (5) is a cylinder head with a corner end ring; the bushing (2) and the corner snap ring surface of the second-stage buffer cylinder head (5) form an annular throttling gap (9).

4. The built-in hydraulic damping buffer actuator as described in claim 3, characterized in that: The bushing (2) has a flange ring on its annular surface that matches the stepped hole at the piston port.

5. The built-in hydraulic damping buffer actuator as described in claim 1, characterized in that: The piston ring seals the piston cylinder (7), and the ring surface has a ring groove for mounting the guide ring. The back end of the guide ring has a rounded transition protrusion, and the bottom of the free end of the piston has a buffer ring groove.

6. The built-in hydraulic damping buffer actuator as described in claim 1, characterized in that: The piston rod (8) has a variable cross-section gradually smooth transition ring arc inside the partition spring cavity, and the variable cross-section gradually smooth transition ring arc is connected to the arc ring of the bushing (2).

7. The built-in hydraulic damping buffer actuator as described in claim 4, characterized in that: The first-stage buffer cylinder head (10), the second-stage buffer cylinder head (5), and the bushing (2) are structurally designed to form a first-stage buffer chamber (3) and a second-stage buffer chamber (4). The bushing (2) is interlocked with the second-stage buffer cylinder head (5) through a corner and sealed inside the stepped hole of the piston rod (8) to form a multi-stage buffer chamber pressure.

8. The built-in hydraulic damping buffer actuator as described in claim 1, characterized in that: When the piston rod (8) extends in reverse direction, the first-stage buffer cylinder head (10) and the second-stage buffer cylinder head (5) extend slowly step by step under the action of the return spring (1) and the return spring (6). Oil from outside the buffer chamber is drawn into the first-stage buffer chamber (3) and the second-stage buffer chamber (4) which are sealed by the ring through the annular gap (9). The buffer structure resets to meet the conditions for the next use.

9. The built-in hydraulic damping buffer actuator as described in claim 8, characterized in that: The first-stage buffer cylinder head (10), the second-stage buffer cylinder head (5), and the bushing (2) are encapsulated in the first-stage buffer cavity (3) and the second-stage buffer cavity (4) inside the piston rod (8) through structural design, forming a short-stroke buffer. When the piston rod retracts, the first-stage buffer cylinder head (10) moves to the left under the action of oil pressure, realizing the rapid start-up of the hydraulic piston cylinder (7) when the piston rod retracts.

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