Hydraulic actuator

Abstract

The utility model discloses a hydraulic executing device which comprises a hydraulic cylinder, a piston is arranged in the hydraulic cylinder and divides the hydraulic cylinder into an upper oil cavity and a lower oil cavity, the upper oil cavity is provided with a hydraulic source, the hydraulic source is provided with a conveying device, and the hydraulic source conveys hydraulic oil to the upper oil cavity through the conveying device. The piston is connected to a piston rod, the piston rod penetrates out of an upper sealing cover of the hydraulic cylinder, the piston rod and the upper sealing cover are in sealing connection, a pre-storage spring is installed on the upper sealing cover, the upper end of the pre-storage spring is installed at the upper end of the piston rod, the lower end of the pre-storage spring is supported on the upper sealing cover, and a translation mechanism is arranged between the pre-storage spring and the upper sealing cover. Through the translation mechanism, the radial unbalance loading force generated when the spring works can be released, the common radial unbalance loading and additional bending moment of the actuator are overcome, and therefore the movement precision, the comprehensive performance and the service life of the hydraulic actuator are guaranteed.

Description

Technical Field

[0001] This invention relates to a hydraulic actuator, used in various mechanical structures or systems as a general-purpose drive device. It can be used to control industrial valves and meet diverse needs. Background Technology

[0002] Hydraulic actuators are primarily used in industrial automation control systems. End users have increasingly higher requirements for actuators, including their intelligence, durability, precision, stability, and reliability. The trend towards industrial upgrading and intelligent manufacturing demands further advancements and improvements in actuator products. However, due to unresolved technological bottlenecks, unstable product quality, low yield rates, and oil leaks in hydraulic products, these products struggle to penetrate the mainstream market.

[0003] Existing hydraulic actuators typically employ a wire-wound spring structure as a reset device. However, the inherent drawbacks of wire-wound springs include unavoidable destructive factors such as radial eccentricity and axial bending. The piston rod, as the primary actuator, oscillates with the spring, failing to achieve effective centering. This oscillation constantly damages other parts in contact with it, particularly causing wear and damage to the seals between the hydraulic cylinder's sealing cap and the piston rod. This can lead to hydraulic oil leakage and ultimately, complete actuator failure.

[0004] A hydraulic actuator, as disclosed in Chinese Patent Document CN212536874U, includes a hydraulic cylinder and a hydraulic power source installed inside a housing. An upper sealing cover is provided on the upper part of the hydraulic cylinder, and the hydraulic power source is installed on the upper sealing cover. A lower sealing cover is provided on the lower part of the hydraulic cylinder and installed at the bottom of the housing. A piston is installed inside the hydraulic cylinder, dividing it into an upper oil chamber and a lower oil chamber. The hydraulic power source is connected to the upper oil chamber of the hydraulic cylinder through a first channel (oil pipe) and a second channel (oil pipe), and to the lower oil chamber of the hydraulic cylinder through a third channel (oil pipe). The hydraulic power source delivers hydraulic oil to the upper oil chamber via an oil pump through the first channel. The second channel is controlled to open or close by a solenoid valve. The piston is connected to a piston rod, with the upper end of the piston rod extending through the upper sealing cover and the lower end extending through the lower sealing cover. The piston rod is sealed to both the upper and lower sealing covers. A pre-loaded spring is provided on the upper side of the hydraulic cylinder, with its upper end connected to the piston rod, its lower end mounted on the upper sealing cover, and its lower end freestanding on the lower sealing cover. The pre-loaded spring inevitably suffers from destructive factors such as radial off-center load and axial bending. The piston rod swings with the pre-loaded spring, which will wear and damage the seal between the piston rod and the upper sealing cover. Utility Model Content

[0005] The technical problem to be solved by this utility model is to provide a hydraulic actuator that can improve the stability, safety, economy, maintainability and service life of the operation, and effectively release the radial off-center load force when the spring is working.

[0006] To achieve the above-mentioned technical objectives, the technical solution of this utility model is as follows:

[0007] A hydraulic actuator includes a hydraulic cylinder, within which a piston is disposed, dividing the hydraulic cylinder into an upper oil chamber and a lower oil chamber. A hydraulic source is disposed in the upper oil chamber, and a conveying device is provided with the hydraulic source to deliver hydraulic oil to the upper oil chamber via the conveying device. The piston is connected to a piston rod, which extends through an upper sealing cover of the hydraulic cylinder. The piston rod and the upper sealing cover are sealed together. A pre-loaded spring is mounted on the upper sealing cover, with its upper end mounted on the upper end of the piston rod and its lower end supported on the upper sealing cover. A translational mechanism is provided between the pre-loaded spring and the upper sealing cover.

[0008] The translational mechanism includes multiple rolling elements, and a spring support is provided between the rolling elements and the pre-stored spring. The lower end of the pre-stored spring is supported on the spring support, and the multiple rolling elements support the bottom of the spring support. When the spring is compressed and rotates, the spring support can automatically move and rotate on the upper sealing plate to release the radial off-center load of the spring, overcome the radial off-center load and additional bending moment commonly found in actuators, thereby ensuring the motion accuracy, overall performance and service life of the hydraulic actuator.

[0009] Preferably, the rolling element is a spherical roller or a cylindrical roller.

[0010] The rolling element is provided with a limiting component, which is used to keep the rolling element at the bottom of the spring support.

[0011] The limiting component is a retaining groove, which is located at the bottom of the spring support or on the upper sealing cover. Placing the rolling element within the retaining groove prevents the rolling element from detaching from the bottom of the spring support.

[0012] The limiting component is an annular retainer with multiple limiting holes evenly distributed along its circumference. The rolling elements are respectively disposed within these limiting holes. The annular retainer is sleeved around the piston rod and located at the bottom of the spring support. The rolling elements rotate within the limiting holes of the annular retainer, thus limiting their movement and preventing them from detaching from the bottom of the spring support.

[0013] The limiting hole is larger than the diameter of the rolling element, allowing the rolling element to roll and displace within the limiting hole. The rolling element can rotate and move freely within the limited range of the limiting hole, effectively releasing the radial off-center load of the spring.

[0014] To further eliminate the radial off-center load force during spring operation and reduce the impact of spring head swaying on the piston rod, the piston rod includes a main shaft and an adjusting shaft. The upper end of the pre-stored spring is connected to the adjusting shaft, which is movably connected above the main shaft via a pin. The pin is provided in a pin groove; when the upper piston rod swings, the pin moves back and forth in the pin groove. When the spring head moves, the adjusting shaft moves on the main shaft, reducing the impact of spring swaying on the main shaft.

[0015] The top end of the main shaft is provided with a connecting groove, the pin is provided on the connecting groove, the bottom end of the adjusting shaft is provided with a connecting block, the pin slide groove is provided on the connecting block, and the pin is located in the pin slide groove.

[0016] The piston rod extends through the lower sealing cover of the hydraulic cylinder, and there is a sealed connection between the piston rod and the lower sealing cover.

[0017] This invention, through a coaxial two-section piston rod and translation mechanism, can effectively release the radial off-center load force when the spring is working, overcoming the radial off-center load and additional bending moment commonly found in actuators, thereby ensuring the motion accuracy, overall performance and service life of the hydraulic actuator. Attached Figure Description

[0018] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0019] Figure 1 This is a schematic diagram of a hydraulic actuator.

[0020] Figure 2 This is a schematic diagram of the pin and adjusting shaft structure.

[0021] Figure 3 This is a schematic diagram of the preloaded spring sleeve structure.

[0022] Figure 4 This is a schematic diagram of a translational mechanism. Detailed Implementation

[0023] like Figure 1-4As shown, the hydraulic actuator includes a housing 1, a lower sealing cover 8 at the bottom of the housing 1, an upper sealing cover 5 above the lower sealing cover 8, a hydraulic cylinder 7 between the lower sealing cover 8 and the upper sealing cover 5, a piston 6 inside the hydraulic cylinder 7, the piston 6 dividing the hydraulic cylinder 7 into an upper oil chamber and a lower oil chamber, a hydraulic source 2 on the upper sealing cover 5, the hydraulic source 2 being connected to the upper oil chamber of the hydraulic cylinder 7 through a first channel and a second channel, and the hydraulic source 2 being connected to the lower oil chamber of the hydraulic cylinder 7 through a third channel, the hydraulic source 2 supplying hydraulic oil to the upper oil chamber through an oil pump (or other similar conveying device) via the first channel, and the second channel being equipped with a solenoid valve (or other similar control valve), the second channel being controlled to open and close by the solenoid valve.

[0024] The piston 6 is connected to the main shaft 12 of the piston rod. The main shaft 12 extends through the upper sealing cover 5 of the hydraulic cylinder, and the main shaft 12 and the upper sealing cover 5 are sealed together. The main shaft 12 extends through the lower sealing cover 8 of the hydraulic cylinder, and the main shaft 12 and the lower sealing cover 8 are sealed together.

[0025] The main shaft 12 is movably connected to the adjusting shaft 16 via a pin 14. Specifically, the top end of the main shaft 12 is provided with a connecting groove 163, and the pin 14 is disposed in the connecting groove 163. The bottom end of the adjusting shaft 16 is provided with a connecting block 161, and the connecting block 161 is provided with a pin slide groove 162. The pin 14 is located within the pin slide groove 162, and the pin 14 moves back and forth within the pin slide groove 162. Of course, the pin slide groove can also be disposed on the connecting groove, and the pin can be disposed on the connecting block; or the connecting groove can be disposed on the adjusting shaft, and the connecting block can be disposed on the main shaft; thus achieving the purpose of movably connecting the main shaft 12 to the adjusting shaft 16 via the pin 14.

[0026] A pre-loaded spring 15 is provided on the upper sealing cover 5. The upper end of the pre-loaded spring 15 is supported by an upper spring support seat 151. The lower end of the pre-loaded spring 15 is supported on the upper sealing cover 5 by a lower spring support seat 152. The upper spring support seat 151 and the lower spring support seat 152 are movably connected by a connecting part 153. The two ends of the connecting part 153 have an upper intermediate boss 154 and a lower intermediate boss 155. The upper spring support seat 151 is provided with an upper spring boss 156, which is located between the upper intermediate boss 154 and the lower intermediate boss 155. The lower spring support seat 152 is provided with a lower spring boss 157, which is located between the upper spring boss 156 and the lower intermediate boss 155.

[0027] The adjusting shaft 16 is threadedly connected to an adjusting nut 20. A preload adjusting seat is provided between the adjusting nut 20 and the connecting part 153. The preload adjusting seat is limited at the upper end of the connecting part 153, thereby connecting the upper end of the preload spring 15 to the adjusting shaft 16.

[0028] A translational mechanism 3 is provided between the lower spring support 152 and the upper sealing cover 5. The translational mechanism 3 includes multiple cylindrical rollers 33 of equal diameter, which are respectively disposed in the limiting holes 34 of the annular cage 32. The limiting holes 34 are evenly distributed around the annular cage 32, and the width of the limiting holes 34 is greater than the diameter of the cylindrical rollers 33, allowing the cylindrical rollers 33 to roll and displace within the limiting holes 34. The annular cage 32 is sleeved on the outside of the main shaft. Both the annular cage 32 and the cylindrical rollers 33 are disposed at the bottom of the lower spring support 152, and the cylindrical rollers 33 are supported between the lower spring support 152 and the upper sealing cover 5. When the pre-stored spring 15 is compressed and moves or rotates, the lower spring support 152 drives the cylindrical rollers 33 to roll within the limiting holes 34, thereby releasing the radial off-center load of the spring. Of course, the rolling elements can also be spherical rollers or other types of rollers.

[0029] The bottom end of the main shaft 12 is connected to the valve stem assembly via a connecting nut 24. Below the bottom end of the main shaft 12, a bracket 9 is connected to the housing 1, and the bracket 9 has a clamping block 26 for connecting the valve.

[0030] A screw 19 is connected to the top end of the adjusting shaft 16. The screw 19 extends through the top of the housing, and a rotating top cover 18 is installed on the top of the housing. Specifically, a screw sleeve 17 is threadedly connected to the top end of the adjusting shaft 16. The screw 19 is located inside the screw sleeve 17 and threadedly connected to the adjusting shaft 16. The screw 19 extends through the top of the housing, and a rotating top cover 18 is installed on the top of the housing. A sealing ring 11 is provided between the screw 19 and the housing 1.

[0031] In another embodiment, the limiting component can be a retaining groove located at the bottom of the spring support (or on the upper sealing cover). A spherical roller (or other type of roller) is partially located within the retaining groove, which limits the spherical roller to ensure it remains at the bottom of the spring support, supported between the spring support and the upper sealing cover. In a further embodiment, the diameter of the retaining groove is larger than the diameter of the spherical roller, allowing the spherical roller to roll within the groove.

[0032] The above embodiments do not limit the present invention in any way. All technical solutions obtained by equivalent substitution or equivalent transformation fall within the protection scope of the present invention.

Claims

1. A hydraulic actuator, comprising a hydraulic cylinder, wherein a piston is disposed within the hydraulic cylinder, the piston dividing the hydraulic cylinder into an upper oil chamber and a lower oil chamber, a hydraulic source is disposed in the upper oil chamber, and a conveying device is disposed in the hydraulic source, the hydraulic source conveying hydraulic oil to the upper oil chamber via the conveying device; the piston is connected to a piston rod, the piston rod extending through an upper sealing cover of the hydraulic cylinder, the piston rod and the upper sealing cover being sealed together, a pre-loaded spring is mounted on the upper sealing cover, the upper end of the pre-loaded spring being mounted on the upper end of the piston rod, and the lower end of the pre-loaded spring being supported on the upper sealing cover, characterized in that: A translational mechanism is arranged between the pre-storage spring and the upper sealing cover.

2. The hydraulic actuator according to claim 1, characterized in that: The translational mechanism comprises a plurality of rolling bodies, and a spring supporting seat is arranged between the rolling bodies and the pre-storage spring.

3. The hydraulic actuator according to claim 2, wherein: The rolling bodies are spherical rollers or cylindrical rollers.

4. The hydraulic actuator according to claim 3, wherein: The rolling bodies are provided with limiting components for keeping the rolling bodies at the bottom of the spring supporting seat.

5. The hydraulic actuator according to claim 4, wherein: The limiting components are retaining grooves arranged on the bottom of the spring supporting seat or the upper sealing cover.

6. The hydraulic actuator of claim 4, wherein: The limiting components are annular retainers provided with a plurality of limiting holes, and the rolling bodies are arranged in the limiting holes.

7. The hydraulic actuator according to claim 6, characterized in that: The limiting holes are larger than the diameter of the rolling bodies.

8. The hydraulic actuator of claim 1, wherein: The piston rod comprises a main shaft and an adjusting shaft, the upper end of the pre-storage spring is connected to the adjusting shaft, the adjusting shaft is movably connected to the upper end of the main shaft through a pin rod, the pin rod is arranged in a pin rod sliding groove, and the pin rod reciprocally displaces in the pin rod sliding groove when the upper piston rod swings.

9. The hydraulic actuator according to claim 8, wherein: The top end of the main shaft is provided with a connecting groove, the pin rod is arranged on the connecting groove, the bottom end of the adjusting shaft is provided with a connecting block, and the pin rod sliding groove is arranged on the connecting block.

10. The hydraulic actuator of claim 1, wherein: The piston rod penetrates through the lower sealing cover of the hydraulic cylinder, and the piston rod and the lower sealing cover are sealingly connected.

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