Hydraulic planetary roller screw spiral oscillating cylinder and hydraulic system

Abstract

The invention belongs to the related technical field of hydraulic swing actuators, and discloses a hydraulic planetary roller screw spiral swing cylinder and a hydraulic system.The swing cylinder comprises a cylinder body, a piston component and a transmission shaft component, the piston component is movably arranged in the cylinder body, one end of the transmission shaft component penetrates through the piston component, and the other end of the transmission shaft component penetrates through the cylinder body; the two are in threaded connection; the piston component comprises a threaded shell and a plurality of pin rollers which are uniformly distributed around the central axis of the threaded shell and are arranged in the threaded shell, and the pin rollers are in threaded connection with the threaded shell; the transmission shaft component is arranged among the multiple pin rollers, the transmission shaft component is in threaded connection with the multiple pin rollers, and the pin rollers can rotate and revolve around the central axis of the threaded shell under the driving of the threaded shell. According to the invention, coexistence of high efficiency and heavy load is realized.

Description

Technical Field

[0001] This invention belongs to the technical field of hydraulic swing actuators, and more specifically, relates to a hydraulic planetary roller screw helical swing cylinder and hydraulic system. Background Technology

[0002] Hydraulic oscillating actuators are a type of fluid power device that specifically converts hydraulic energy into reciprocating rotary motion within a limited angle. Their core function is to output high-torque, high-rigidity, and rapidly responsive mechanical actions within a specific angular displacement range. More specifically, hydraulic oscillating actuators convert hydraulic energy into partial rotational motion.

[0003] A hydraulic helical oscillating cylinder is a device that converts the linear motion of a piston driven by hydraulic energy into the rotational oscillation of an output shaft. More specifically, its core working principle is to utilize a selected helical pair with a large helix angle to convert the linear motion of the piston into the oscillation of the output shaft. Compared with gear racks, pinions, and blades, it has advantages such as compact structure, large torque output, precise oscillation angle, and good operational stability.

[0004] Hydraulic helical swing cylinders have a wide range of applications, primarily in heavy-duty construction machinery, mining and metallurgical machinery, deep-sea robots, aerospace, and special vehicles, where high torque is required to drive rotating components. More importantly, they are widely used in applications demanding high torque, small space, and high reliability. Furthermore, as torque output devices in heavy-duty construction machinery and special vehicles evolve towards higher output torque, stronger adaptability, and energy efficiency, hydraulic helical swing actuators need to meet the operational requirements of these vehicles, demanding high output torque, small size, and high efficiency. However, existing hydraulic helical swing cylinders have the following bottlenecks: Efficiency and heavy-duty capacity are difficult to balance. Existing spiral oscillating cylinders mainly use sliding spiral pairs as the core transmission structure. Due to the structural characteristics of spiral pairs, their transmission efficiency is low. Ball screw pairs can be used as a substitute, but the limitations of the contact points between the balls and the raceways and the curvature of the contact points make it difficult for ball screw pairs to complete heavy-duty tasks.

[0005] A possible solution to improve efficiency, more specifically, is to replace the sliding helical pair with a ball screw pair. The rolling friction between the balls and the raceway replaces the sliding friction of the internal and external threads in the sliding helical pair. Although this can improve mechanical efficiency, the load-bearing capacity of the ball screw pair is much lower than that of the sliding helical pair of the same size and material. This results in a significant decrease in the heavy-load performance of the helical swing cylinder, which cannot meet the usage requirements of heavy-load scenarios. Summary of the Invention

[0006] In view of the above-mentioned defects or improvement needs of the existing technology, the present invention provides a hydraulic planetary roller screw helical swing cylinder and hydraulic system, which aims to solve the problem that heavy load and high efficiency are difficult to coexist in the existing hydraulic swing cylinder.

[0007] To achieve the above objectives, according to one aspect of the present invention, a hydraulic planetary roller screw helical swing cylinder is provided. The swing cylinder includes a cylinder body, a piston component, and a transmission shaft component. The piston component is movably disposed in the cylinder body, and one end of the transmission shaft component passes through the piston component, and the two are threadedly connected. The piston component includes a threaded shell and a plurality of rollers evenly arranged around the central axis of the threaded shell and disposed within the threaded shell, wherein the rollers and the threaded shell are threadedly connected; the drive shaft component is disposed between the plurality of rollers, and the drive shaft component and the plurality of rollers are threadedly connected, wherein the rollers are able to rotate on their own axis and revolve around the central axis of the threaded shell under the drive of the threaded shell.

[0008] Furthermore, the piston assembly also includes a piston end cap, two retainers, and two retaining rings for bores. The piston end cap is threaded to the large end of the threaded housing. The plurality of rollers, the two retainers, and the two retaining rings for bores are all disposed within the threaded housing. The threaded housing and the cylinder body form a movable connection. The two retainers are spaced apart, the two retaining rings for bores are also spaced apart, and the two internal gear rings are also spaced apart. The retainers are located between the retaining rings for bores and the internal gear rings. The two ends of the rollers are respectively connected to the two retainers. The rollers and the internal gear rings form a threaded connection, and the rollers and the threaded housing also form a threaded connection.

[0009] Furthermore, external splines are uniformly arranged on the outer periphery of the threaded shell, and the external splines cooperate with the internal splines of the cylinder body, so that the piston component and the cylinder body form a movable connection.

[0010] Furthermore, the two opposite ends of the threaded shell are respectively provided with a first stepped groove and a second groove. The bottom surface of the first stepped groove is provided with a first groove, and the bottom surface of the first groove is provided with a first internal threaded hole. The bottom surface of the second groove is provided with a third groove, and the third groove is connected to the first internal threaded hole. A fourth annular groove is provided at one end of the first stepped groove adjacent to the first groove. A fifth annular groove is provided at one end of the second groove adjacent to the third groove. Two hole retainers are respectively disposed in the fourth annular groove and the fifth annular groove. Two internal gear rings are respectively disposed in the first groove and the third groove. One retainer is located between one hole retainer and the bottom surface of the first stepped groove, and the other retainer is located between the other hole retainer and the bottom surface of the second groove.

[0011] Furthermore, the piston end cap is provided with a third through hole, and a sealing ring and a first seal are provided at intervals on the inner wall of the third through hole.

[0012] Furthermore, the roller includes a cylindrical body with a roller thread formed in the middle and a roller left gear and a roller right gear provided at both ends. The roller left gear and the roller right gear are respectively provided adjacent to the opposite ends of the roller thread. The opposite ends of the cylindrical body are respectively connected to two cages. The roller thread forms a threaded connection with the first internal threaded hole. The roller left gear and the roller right gear are respectively disposed in two internal gear rings, and the roller left gear and the roller right gear form a threaded connection with the two internal gear rings respectively.

[0013] Furthermore, the pitch diameter of the roller thread, the pitch circle diameter of the left roller gear, and the pitch circle diameter of the right roller gear are equal; the left roller gear and the right roller gear also have threads that mesh with the external threads of the drive shaft of the drive shaft component.

[0014] Furthermore, the swing cylinder also includes a left end cover component, a sealing block component, and a right end cover component. The left end cover component and the right end cover component are respectively connected to opposite ends of the cylinder body. The sealing block component is disposed in the cylinder body and adjacent to the right end cover component. One end of the drive shaft component passes through the right end cover component, the sealing block component, and the piston component in sequence and then extends into the left end cover component.

[0015] Furthermore, an integrated mounting flange is uniformly provided on the outer periphery of one end of the cylinder body adjacent to the right end cover component, and the cylinder body is connected to the output target through the mounting flange; the mounting flange has a main connecting hole extending along the axial direction of the cylinder body, and the main connecting hole cooperates with the connecting screw to connect with the output target; the mounting flange also has an auxiliary threaded hole, and the central axis of the auxiliary threaded hole is perpendicular to the central axis of the main connecting hole.

[0016] The present invention also provides a hydraulic system, wherein the actuator of the hydraulic system adopts the hydraulic planetary roller screw helical swing cylinder as described above.

[0017] In summary, compared with the prior art, the hydraulic planetary roller screw helical swing cylinder and hydraulic system provided by the present invention have the following advantages: 1. Significantly improves transmission efficiency while balancing heavy load and energy saving: High-efficiency transmission mechanism: The planetary roller screw helical pair is used as the core transmission structure. The rolling friction between the rollers and the thread is the main form of motion, which fundamentally overcomes the problem of low efficiency caused by sliding friction in traditional sliding screw pairs, and significantly improves energy saving effect.

[0018] Heavy-duty capacity maintained: Although primarily rolling, the use of threaded engagement allows multiple rollers to share the load simultaneously, resulting in a large contact area. Furthermore, the roller threads have a large radius of curvature, leading to high surface contact strength and a load-bearing capacity far exceeding that of ball screw pairs of the same size. Therefore, this invention achieves high efficiency without sacrificing heavy-duty capacity, breaking the traditional dilemma of "high efficiency without heavy load, heavy load without high efficiency."

[0019] 2. Achieving an ultra-large output angle and a wide range of applications: By rationally designing the lead and effective working length of the external thread and roller thread of the transmission shaft, the linear stroke of the piston can be converted into a rotational angle of over 360° for the transmission shaft. This breaks through the angle limitations of crank-connecting rod type (<180°) and vane type (single vane <360°, double vane <180°) structures, meeting a wider range of working conditions. More specifically, compared to traditional helical oscillating cylinders, changes in the helix angle do not significantly alter the transmission efficiency, resulting in a larger maximum output angle range for this invention compared to traditional helical oscillating cylinders.

[0020] Compact design: This large-angle output capability is achieved within a highly compact piston assembly without significantly increasing the overall size, while maintaining high energy density.

[0021] 3. High energy density, compact and reliable structure: Highly integrated design: The complex planetary reduction gear and helical transmission mechanism are highly integrated inside the piston, replacing the bulky external gear rack, connecting rod, and shift fork mechanisms. More specifically, it eliminates the additional guiding and supporting structures required by the gear rack mechanism, significantly reducing the overall size and weight.

[0022] Simplification and Reliability: Compared with ball screw pairs that require complex reversers and circulation channels, planetary roller screw pairs have a simple structure, do not require a return mechanism, and are especially suitable for low-speed and heavy-load conditions. They avoid the risk of ball jamming or poor circulation and have high operational reliability.

[0023] 4. Smooth operation and high positioning accuracy: Synchronous forced mechanism: The cage is set to force all rollers to rotate synchronously around the sun and on their own axis, which effectively avoids the problems of discontinuous movement, impact or noise caused by some rollers slipping or jamming when the load is uneven, and ensures the smoothness of transmission.

[0024] Backlash-free transmission: The precision meshing planetary helical pair itself has a very small transmission clearance. Combined with the precise guidance of the spline fit between the piston component and the cylinder, it achieves extremely small backlash. The positioning accuracy and repeatability are far higher than other transmission forms, such as the gear and rack transmission in the gear and rack type oscillating actuator.

[0025] 5. Reliable sealing, suitable for harsh working conditions: A reliable sealing system employs multi-stage combined seals (such as Glyd rings, Y-rings, O-rings, etc.) and an independent sealing block structure, effectively isolating the hydraulic oil chamber from the bearing chamber. This ensures that the lubricant in the bearing chamber remains relatively clean compared to the hydraulic oil chamber, improving the reliability and lifespan of the thrust needle roller bearing and resulting in high volumetric efficiency. This allows the invention to adapt to high-pressure working environments and operate stably for extended periods under low-speed, heavy-load, and even intermittent working conditions.

[0026] 6. Convenient installation and maintenance, strong vibration resistance: The integrated flange on the cylinder block changes the traditional flange hole structure, avoiding the phase difference caused by the machining of hub hole, drive shaft thread, piston thread, and piston internal spline during drive shaft machining, and solving the problem of inconvenient alignment between the threaded through hole on the integrated flange and the threaded hole on the installation target surface.

[0027] Anti-loosening design: The auxiliary threaded hole anti-loosening structure on the cylinder mounting flange effectively prevents the connection from loosening under continuous torque impact and vibration by tightening the main mounting screw from the side, thus improving the safety and reliability of the whole machine under harsh working conditions.

[0028] 7. Different components can be assembled using a modular approach. More specifically, the piston component, which has the highest requirements for manufacturing and installation precision in this invention, is assembled as a pre-assembled modular unit, simplifying on-site installation and subsequent maintenance processes and increasing reliability.

[0029] This invention applies the highly efficient, high-rigidity, and high-load-bearing planetary roller screw pair to a hydraulic oscillating cylinder, successfully combining advantages such as "high efficiency," "high torque (heavy load)," "large angle," "high precision," "high reliability," and "compact structure"—advantages that are difficult to achieve simultaneously in traditional oscillating cylinders. It is not only a structural innovation but also a comprehensive improvement in system performance, making it particularly suitable for heavy-load, low-speed, large-angle precision drive applications with stringent performance requirements. Attached Figure Description

[0030] Figure 1 This is a three-dimensional isometric view of a hydraulic planetary roller screw helical swing cylinder provided in an embodiment of the present invention; Figure 2 yes Figure 1 Axial sectional view of the hydraulic planetary roller screw helical swing cylinder in the image; Figure 3 yes Figure 1 A three-dimensional isometric view of the cylinder body of a hydraulic planetary roller screw helical swing cylinder. Figure 4 yes Figure 3 Axial sectional view of the cylinder block; Figure 5 yes Figure 1 A schematic diagram of the piston component of a hydraulic planetary roller screw helical swing cylinder; Figure 6 yes Figure 5 An axial sectional view of the piston component in the image; Figure 7 yes Figure 5 A schematic diagram of the rollers in the piston component; Figure 8 yes Figure 5 An exploded view of the piston component; Figure 9 yes Figure 1 A schematic diagram of the left end cover component of the hydraulic planetary roller screw helical swing cylinder; Figure 10 yes Figure 9 A sectional view of the left end cap component; Figure 11 yes Figure 1 A schematic diagram of the right end cover component of the hydraulic planetary roller screw helical swing cylinder; Figure 12 yes Figure 1 A schematic diagram of the drive shaft component of a hydraulic planetary roller screw helical swing cylinder; Figure 13 yes Figure 1 A schematic diagram of the sealing block component of a hydraulic planetary roller screw helical swing cylinder.

[0031] In all the accompanying drawings, the same reference numerals are used to denote the same elements or structures, wherein: 1-cylinder body, 12-mounting flange, 121-main connecting hole, 123-auxiliary threaded hole, 1311-left oil hole, 1312-right oil hole, 132-sealing groove, 133-cylinder mounting threaded hole, 14-axial positioning step, 15-internal spline, 16-second threaded hole, 2-left end cover assembly, 21-left positioning block, 22-left end cover, 23-second sealing ring, 24-first Y-type sealing ring, 25-left bushing, 3-piston assembly, 31-threaded shell, 311-support ring, 312-Glyd ring, 313-external spline, 32-piston Plug end cap, 321-Sealing ring, 322-First sealing ring, 323-End cap locating pin, 33-Roller, 331-Roller thread, 332-Roller left gear, 333-Roller right gear, 34-Cage, 35-Bore circlip, 36-Internal gear ring locating pin, 4-Sealing block assembly, 41-Sealing block, 42-Radial sealing ring, 43-Axial sealing ring, 44-Third Y-type sealing ring, 45-Right bushing, 5-Right end cap assembly, 51-Right end cap, 52-External thread, 53-Second Y-type sealing ring, 6-Drive shaft assembly, 61-Drive shaft external thread, 62-Shoulder, 63-Molded surface connecting hub hole, 7-Thrust needle roller bearing. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0033] This invention provides a hydraulic planetary roller screw helical swing cylinder. The swing cylinder integrates a set of planetary roller screw helical pairs in the piston component 3. During operation, hydraulic oil drives the piston to move axially, and then the linear motion is efficiently and smoothly converted into the rotational motion output of the transmission shaft through the planetary roller screw helical pairs, realizing the coexistence of heavy load and high efficiency.

[0034] The core transmission pair of the swing cylinder adopts a ball screw pair, which fully utilizes the high efficiency, compact structure, and large load-bearing capacity of the ball screw pair. This significantly improves energy conversion efficiency with minimal impact on the load-bearing capacity of the hydraulic helical swing cylinder, effectively solving the bottleneck problems of existing technologies. The ball screw transmission pair is a mechanical transmission device that converts rotary motion into linear motion. Power transmission is achieved through the meshing of the screw, nut, and multiple rollers. It has outstanding advantages such as high load-bearing capacity, good environmental adaptability, and long service life, and is widely used in precision machinery and automation systems.

[0035] This invention utilizes a roller screw pair instead of a traditional helical pair to solve the problem that existing helical swing cylinder solutions cannot simultaneously meet the requirements of high efficiency and energy saving and high load-bearing capacity, and further improves the output angle range of the hydraulic helical swing cylinder.

[0036] Please see Figure 1 and Figure 2 The swing cylinder includes a cylinder body 1, a left end cap component 2, a piston component 3, a sealing block component 4, a drive shaft component 6, and a right end cap component 5. The left end cap component 2 and the right end cap component 5 are respectively connected to opposite ends of the cylinder body 1. The piston component 3 is movably disposed within the cylinder body 1. The sealing block component 4 is disposed within the cylinder body 1 and adjacent to the right end cap component 5. One end of the drive shaft component 6 passes sequentially through the right end cap component 5, the sealing block component 4, and the piston component 3 before extending into the left end cap component 2. The piston component 3 drives the drive shaft component 6 to rotate by moving.

[0037] Please see Figure 3 and Figure 4 The cylinder body 1 is stepped, with a first threaded hole and a second threaded hole 16 at each end. A first through hole and a second through hole are formed on the bottom surface of the first threaded hole, respectively, and the second through hole communicates with the second threaded hole 16. A first annular groove and a second annular groove are formed at both ends of the first through hole, respectively. A second annular groove is formed at the end of the second threaded hole 16 adjacent to the second through hole, and an axial positioning step 14 is formed between the second annular groove and the first annular groove. Multiple evenly distributed internal splines 15 are formed on the inner wall of the first through hole. The cylinder body 1 also has a left oil hole 1311 and a right oil hole 1312, both of which communicate with the first threaded hole. A sealing groove 132 is also formed at the end of the left oil hole 1311 and the right oil hole 1312, which cooperates with a corresponding sealing element to seal the left oil hole 1311 and the right oil hole 1312.

[0038] The left oil hole 1311 and the right oil hole 1312 are used to input oil into the cylinder body 1 or discharge oil from the cylinder body 1, so that the pressure of the oil can be transmitted to the piston component 3, pushing the piston component 3 to smoothly complete axial movement. The cylinder body is also provided with a cylinder mounting threaded hole 133 for installation.

[0039] The cylinder body 1 has mounting flanges 12 evenly distributed on the outer periphery of one end where a second threaded hole 16 is provided. The cylinder body 1 is connected to the output target through the mounting flanges 12. The mounting flange 12 has a main connecting hole 121 extending axially along the cylinder body 1. The main connecting hole 121 mates with a connecting screw to connect to the output target. The mounting flange 12 also has an auxiliary threaded hole 123, the central axis of which is perpendicular to the central axis of the main connecting hole 121. The auxiliary threaded hole 123 mates with a positioning screw to prevent the screws from loosening due to torque transmission or vibration, thereby affecting the transmission stability.

[0040] The axial positioning step 14 is used to position the thrust needle roller bearing 7 and the transmission shaft component 6. The cylinder body 1 is threadedly connected to the left end cover component 2 and the right end cover component 5 through the first threaded hole and the second threaded hole 16, respectively. The inner wall of the end of the first threaded hole adjacent to the first through hole is unthreaded and has a smooth surface.

[0041] Please see Figure 5 , Figure 6 , Figure 7 and Figure 8 The piston component 3 is stepped, with its opposite ends (large end and small end) respectively disposed in the first threaded hole and the first through hole. The piston component 3 includes a threaded shell 31, a piston end cap 32, multiple rollers 33, two retainers 34, and two retaining rings 35. The piston end cap 32 is threaded to the large end of the threaded shell 31. The multiple rollers 33, the two retainers 34, and the two retaining rings 35 are all disposed within the threaded shell 31. The threaded shell 31 forms a movable connection with the cylinder body 1. The two retainers 34 are spaced apart, the two retaining rings 35 are also spaced apart, and the two internal gear rings are also spaced apart. The retainers 34 are located between the retaining rings 35 and the internal gear rings. The multiple rollers 33 are evenly arranged around the central axis of the threaded shell 31, and the two ends of each roller 33 are respectively connected to the two retainers 34. The roller 33 is threadedly connected to the internal gear ring, and the roller 33 is also threadedly connected to the threaded housing 31. It rotates and revolves under the drive of the threaded housing 31.

[0042] A support ring 311 and a Gladley ring 312 are respectively embedded on the outer periphery of one end of the threaded shell 31 located inside the first threaded hole. A first stepped groove and a second recess are respectively formed at opposite ends of the threaded shell 31. A first recess is formed on the bottom surface of the first stepped groove, and a first internal threaded hole is formed on the bottom surface of the first recess. A third recess is formed on the bottom surface of the second recess, and the third recess communicates with the first internal threaded hole. A fourth annular groove is formed at the end of the first stepped groove adjacent to the first recess. A fifth annular groove is formed at the end of the second recess adjacent to the third recess. External splines 313 are evenly distributed on the outer periphery of the threaded shell 31. The external splines 313 cooperate with the internal splines 15, forming a movable connection between the piston component 3 and the cylinder body 1, and restricting the circumferential freedom of the piston component 3.

[0043] Two retaining rings 35 are respectively disposed in the fourth annular groove and the fifth annular groove, and two internal gear rings are respectively disposed in the first groove and the third groove. One retainer 34 is located between one retaining ring 35 and the bottom surface of the first stepped groove, and the other retainer 34 is located between the other retaining ring 35 and the bottom surface of the second groove.

[0044] The piston end cap 32 is threadedly connected to the first stepped groove and is stepped in shape. The piston end cap 32 has a third through hole, and a sealing ring 321 and a first sealing ring 322 are spaced apart on the inner wall of the third through hole. An end cap positioning pin 323 is provided between the piston end cap 32 and the threaded shell 31. The end cap positioning pin 323 serves to prevent loosening and restrict the piston end cap 32 from becoming loose during operation.

[0045] The roller 33 comprises a cylinder with a roller thread 331 formed in the middle. A left roller gear 332 and a right roller gear 333 are disposed at both ends, adjacent to opposite ends of the roller thread 331. The opposite ends of the cylinder are connected to two retainers 34. The roller thread 331 forms a threaded connection with the first internal threaded hole. The left roller gear 332 and the right roller gear 333 are respectively disposed within two internal gear rings, and each forms a threaded connection with one of the two internal gear rings. The internal gear ring is positioned within the threaded housing 31 via an internal gear ring locating pin 36. The locating pin 36 is located within a combination hole on both the internal gear ring and the threaded housing 31, forming an interference fit with the combination hole. The combination hole is drilled after the threaded housing 31 and the internal gear ring are relatively fixed using special tooling. Part of the combination hole is on the threaded housing 31, and another part is on the internal gear ring. A tooling threaded hole is provided for easy disassembly. The retainer 34 is positioned adjacent to the internal gear ring, simultaneously confining it within a corresponding groove. A retaining spring 35 is positioned adjacent to the retainer 34 in the hole, serving as a limiting element to prevent the retainer 34 from dislodging from the groove.

[0046] In this embodiment, the pitch diameter of the roller thread 331, the pitch circle diameter of the left roller gear 332, and the pitch circle diameter of the right roller gear 333 are equal. The roller thread 331 simultaneously meshes with both the threaded housing 31 and the drive shaft component 6. The left roller gear 332 and the right roller gear 333 also have threads that mesh with the external thread 61 of the drive shaft component 6, thus avoiding interference between the external thread 61 of the drive shaft and the gear portion.

[0047] The cage 34, through its pockets, accommodates and constrains both ends of the rollers, forcing all rollers to perform synchronized circular revolution and rotation around their own axes. The double protection provided by the cage 34 and the internal gear ring ensures that the several rollers simultaneously meshing with the first internal threaded hole of the threaded housing 31 and the external thread 61 of the drive shaft maintain synchronized movement. Specifically, the meshing of the left roller gear 332 and the right roller gear 333 with the internal gear ring initially ensures synchronized roller movement. When the internal gear ring loses some teeth due to vibration, fatigue, corrosion, etc., the cage 34 forcibly synchronizes the movement of several rollers. The left roller gear 332 and the right roller gear 333 simultaneously possess teeth and threads. These threads can use lower dimensions with larger basic deviations, thus reliably avoiding interference between the gears and the screw threads.

[0048] Please see Figure 9 and Figure 10The left end cap component 2 is stepped and includes a left positioning block 21, a left end cap 22, a second sealing ring 23, a first Y-shaped sealing ring 24, and a left bushing 25. The left end cap 22 is threadedly connected to the first threaded hole, and one end of the left end cap 22 has a receiving hole. The bottom surface of the receiving hole has a fourth through hole, which penetrates the left end cap 22. The left bushing 25 is disposed within the receiving hole. The left positioning block 21 is connected to the left end cap 22 and seals one end of the left bushing 25. The first Y-shaped sealing ring 24 is embedded in the inner wall of the fourth through hole. The second sealing ring 23 is disposed on the outer periphery of the left end cap. The left positioning block 21 is used to indicate the axial position deviation of the drive shaft component 6 during installation, which may occur due to installation errors or insufficient machining accuracy. When the drive shaft is positioned to the left, the left positioning block 21 cannot be installed correctly; when the drive shaft is positioned to the right, the left end face of the drive shaft is positioned to the right relative to the end face of the receiving hole on the left end cover, which can be observed. The left positioning block 21 protects the left end face of the drive shaft and reduces the machining difficulty of the left end cover. The left bushing 25 and the right bushing 45 in the right end cover component 5 together provide radial positioning for the drive shaft.

[0049] Please see Figure 11 The right end cap component 5 includes a right end cap 51. A fourth groove and a fifth through hole are respectively formed at opposite ends of the right end cap 51, with the fifth through hole communicating with the fourth groove. Two thrust needle roller bearings 7 are spaced apart within the fourth groove. A second Y-shaped sealing ring 53 is embedded in the inner wall of the fifth through hole. An external thread 52 is formed on the outer periphery of the right end cap 51, and this external thread 52 forms a threaded connection with the second threaded hole 16.

[0050] Please see Figure 13 The sealing block component 4 is disposed within the second through hole and the second annular groove, and is connected to the right end cover 51. The right end cover 51 is stepped, with a through second stepped groove. The sealing block component 4 includes a sealing block 41, a radial sealing ring 42, an axial sealing ring 43, a third Y-shaped sealing ring 44, and a right bushing 45. The right bushing 45 is disposed within the second stepped groove and abuts against the stepped surface of the second stepped groove. The right bushing 45 contacts the thrust needle roller bearing 7. The axial sealing ring 43 is disposed on the end face of the sealing block 41. The radial sealing ring 42 is disposed on the circumferential surface of the sealing block 41. The sealing block 41 performs both sealing and axial positioning functions for the drive shaft during operation. The step formed by the sealing block presses against the cylinder body 1, and the corresponding thrust needle roller bearing 7 presses against the right end cover 51, thereby achieving axial positioning of the sealing block.

[0051] Please see Figure 12 The drive shaft component 6 includes a stepped drive shaft. One end of the drive shaft has a profiled connecting hub hole 63 and a shoulder 62. The drive shaft also has an external thread 61. The step is located within the fourth groove and is positioned between the two thrust needle roller bearings 7. One end of the drive shaft passes sequentially through the fifth through hole, one thrust needle roller bearing 7, the fourth groove, another thrust needle roller bearing 7, the second stepped groove, a retaining ring 35, a cage 34, a hole composed of multiple rollers, another cage 34, another retaining ring 35, the third through hole, and the fourth through hole before extending into the left bushing 25. The external thread 61 of the drive shaft meshes with the roller thread 331 to form a threaded connection.

[0052] When oil enters from the oil hole on one side of the cylinder 1 and pushes the piston to move axially, the first internal thread hole and the external thread 61 of the drive shaft are driven by the rollers, forcing the drive shaft to rotate; and the rotation direction of the drive shaft is jointly determined by the movement direction of the piston and the direction of the thread. The cage 34 forces all the rollers to perform synchronous circumferential revolution and rotation.

[0053] The effective thread length and thread helix angle of the external thread 61 of the drive shaft are designed such that when the piston component 3 completes its entire stroke axial movement within the cylinder 1, it can drive the drive shaft to rotate more than 360°. By designing the lead and effective thread length of the external thread of the drive shaft, the full axial displacement of the piston within the cylinder 1 can be converted into a rotation angle of more than 360 degrees for the drive shaft.

[0054] Various sealing methods, such as O-rings, Y-rings, and Glyd rings 312, are used to achieve the aforementioned reliable sealing effect. The oil chamber where the thrust needle roller bearing 7 is located is isolated from the oil chamber where the piston is located by a suitable sealing structure, so that the thrust needle roller bearing 7 can use a more suitable lubricating medium and avoid the lubricating medium from being affected by debris and other contaminants generated in the hydraulic system.

[0055] The external thread 61 of the drive shaft, the first internal threaded hole, the roller, the internal gear ring, and the cage 34 constitute a planetary roller screw helical pair. In this embodiment, the drive shaft, the roller, and the first threaded hole all adopt right-hand threads, and their running direction corresponds to the oil input direction. When oil enters the left oil chamber through the left oil hole 1311, the piston component 3 is pushed to move axially to the right, and the piston assembly squeezes the oil in the right oil chamber, expelling the oil from the right oil chamber. At this time, viewed from the right end of the drive shaft, the drive shaft rotates clockwise. When oil enters the right oil chamber through the right oil hole 1312, the piston component 3 is pushed to move axially to the left, and viewed from the right end of the drive shaft, the drive shaft rotates counterclockwise. The ratio of the rotation angle of the drive shaft to the axial displacement of the piston component 3 is determined by the helix angle of the external thread 61 of the drive shaft; the output torque and angle are transmitted to the target brake through the profiled connecting hub hole 63 at the right end of the drive shaft, realizing torque output. The motion of the rollers: The meshing between the rollers, the external thread 61 of the drive shaft, and the first internal thread hole is the core transmission structure. During the movement of the piston component 3, the roller thread 331 and the external thread 61 of the drive shaft exhibit both squeezing meshing and two relative motion forms: pure rolling or pure sliding. In the pure rolling state: when the piston component 3 moves to the right, the rollers rotate clockwise and revolve counterclockwise; when the piston component 3 moves to the left, the rollers rotate counterclockwise and revolve clockwise. In the pure sliding state: the rollers do not rotate or revolve, and the external thread 61 of the drive shaft and the roller thread 331 only have sliding meshing. Since the number of starts of the first internal thread hole and the external thread 61 of the drive shaft is the same, the helical pair will not experience a sudden change in the helix angle, thus ensuring the smooth operation of the swing cylinder.

[0056] In a mixed motion state: some rollers and the external thread 61 of the drive shaft exhibit pure rolling, while others exhibit pure sliding. Without the constraint of the cage 34, the purely sliding rollers will not revolve or rotate, while the purely rolling rollers will revolve and rotate simultaneously, potentially leading to inconsistent motion or even mutual interference among the rollers. The function of the cage 34 is to force the rollers to maintain synchronous motion; more specifically, it ensures that rollers that should slide also participate in revolve and rotation, or allows rollers that should roll to slide under certain conditions, thereby unifying the motion speed and trajectory. In addition, the cage 34 also assists in the installation and positioning of the piston component 3.

[0057] The assembly process is briefly described as follows: First, install all standard parts such as sealing rings, support rings, and various bushings into their corresponding mounting slots. Second, assemble the core piston component 3: Use the internal gear ring locating pin 36 and the hole retainer 35 to restrict the circumferential and circumferential degrees of freedom of the internal gear ring on both sides inside the threaded housing 31. Install the roller and cage 34 into the threaded housing 31, ensuring that the left roller gear 332 and right roller gear 333 at both ends of the roller mesh with the internal gear ring, and that the roller thread 331 in the middle of the roller initially meshes with the first internal threaded hole in the threaded housing 31. Then, use the hole retainer 35 to axially limit the cage 34. Finally, screw the piston end cap 32 to the left end of the threaded housing 31 and use the end cap locating pin 323 to prevent loosening. Subsequently, install the piston component 3 into the cylinder 1 from left to right, so that the external spline 313 precisely meshes with the internal spline 15 of the cylinder 1, completing the circumferential restriction of the threaded housing 31. Next, install the left end cover component 2: fasten the left end cover to the left end of the cylinder body 1 with screws, and fix the left positioning block 21 to the left end cover with screws. Then, pre-assemble the drive shaft assembly: sequentially insert the thrust needle roller bearing 7 and the sealing block onto the left and right ends of the drive shaft shoulder 62. Key installation step: Insert the pre-assembled drive shaft assembly from the right end of the cylinder body 1 to the left. Since the external thread 61 of the drive shaft will naturally mesh with the roller thread 331 in the piston component 3, the drive shaft needs to be rotated to screw it in until its left end contacts the left positioning block 21 or reaches the manual tightening limit. This process completes the engagement of the planetary screw pair. Finally, install the right end cover component 5: screw the right end cover into the right end thread of the cylinder body 1 until the sealing block and the thrust needle roller bearing 7 are pressed together, completing the encapsulation of the entire swing cylinder. Furthermore, the swing cylinder is connected to the target equipment via the mounting flange 12 on the cylinder body 1. More specifically, screws are used to connect the cylinder to the target equipment through the main connection hole 121 on the flange. After the connection is completed, a preferred screw is screwed into the auxiliary threaded hole 123 and squeezed against the screw in the through hole to prevent loosening.

[0058] The present invention also provides a hydraulic system, wherein the actuator of the hydraulic system adopts the hydraulic planetary roller screw helical swing cylinder as described above.

[0059] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements 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 hydraulic planetary roller screw helical swing cylinder, characterized in that: The swing cylinder includes a cylinder body, a piston component, and a transmission shaft component. The piston component is movably disposed in the cylinder body, and one end of the transmission shaft component passes through the piston component, with the two forming a threaded connection. The piston component includes a threaded shell and a plurality of rollers evenly arranged around the central axis of the threaded shell and disposed within the threaded shell, wherein the rollers and the threaded shell are threadedly connected; the drive shaft component is disposed between the plurality of rollers, and the drive shaft component and the plurality of rollers are threadedly connected, wherein the rollers are able to rotate on their own axis and revolve around the central axis of the threaded shell under the drive of the threaded shell.

2. The hydraulic planetary roller screw helical swing cylinder as described in claim 1, characterized in that: The piston assembly further includes a piston end cap, two retainers, and two retaining rings for bores. The piston end cap is threaded to the large end of the threaded housing. Multiple rollers, two retainers, two retaining rings for bores, and two internal gear rings are all disposed within the threaded housing. The threaded housing and the cylinder body form a movable connection. The two retainers are spaced apart, the two retaining rings for bores are also spaced apart, and the two internal gear rings are also spaced apart. The retainers are located between the retaining rings for bores and the internal gear rings. The two ends of each roller are respectively connected to the two retainers. The rollers and the internal gear rings form a threaded connection, and the rollers and the threaded housing also form a threaded connection.

3. The hydraulic planetary roller screw helical swing cylinder as described in claim 2, characterized in that: External splines are uniformly arranged on the outer periphery of the threaded shell. The external splines cooperate with the internal splines of the cylinder body, so that the piston component and the cylinder body form a movable connection.

4. The hydraulic planetary roller screw helical swing cylinder as described in claim 2, characterized in that: The threaded shell has a first stepped groove and a second recess at opposite ends. The bottom surface of the first stepped groove has a first recess, and the bottom surface of the first recess has a first internal threaded hole. The bottom surface of the second recess has a third recess, which communicates with the first internal threaded hole. A fourth annular groove is formed at one end of the first stepped groove adjacent to the first recess. A fifth annular groove is formed at one end of the second recess adjacent to the third recess. Two retaining rings are respectively disposed in the fourth annular groove and the fifth annular groove. Two internal gear rings are respectively disposed in the first recess and the third recess. One retainer is located between one retaining ring and the bottom surface of the first stepped groove, and the other retainer is located between the other retaining ring and the bottom surface of the second recess.

5. The hydraulic planetary roller screw helical swing cylinder as described in claim 4, characterized in that: The piston end cap has a third through hole, and a sealing ring and a first seal are spaced apart on the inner wall of the third through hole.

6. The hydraulic planetary roller screw helical swing cylinder as described in claim 4, characterized in that: The roller includes a cylindrical body with a roller thread formed in the middle and a left roller gear and a right roller gear provided at both ends. The left roller gear and the right roller gear are respectively located adjacent to the opposite ends of the roller thread. The opposite ends of the cylinder are respectively connected to two cages. The roller thread forms a threaded connection with the first internal threaded hole. The left roller gear and the right roller gear are respectively disposed in two internal gear rings, and the left roller gear and the right roller gear form a threaded connection with the two internal gear rings respectively.

7. The hydraulic planetary roller screw helical swing cylinder as described in claim 6, characterized in that: The pitch diameter of the roller thread, the pitch circle diameter of the left roller gear, and the pitch circle diameter of the right roller gear are all equal; the left roller gear and the right roller gear also have threads that mesh with the external threads of the drive shaft of the drive shaft component.

8. The hydraulic planetary roller screw helical swing cylinder according to any one of claims 1-7, characterized in that: The swing cylinder also includes a left end cover component, a sealing block component, and a right end cover component. The left end cover component and the right end cover component are respectively connected to opposite ends of the cylinder body. The sealing block component is disposed in the cylinder body and adjacent to the right end cover component. One end of the drive shaft component passes through the right end cover component, the sealing block component, and the piston component in sequence and then extends into the left end cover component.

9. The hydraulic planetary roller screw helical swing cylinder as described in claim 8, characterized in that: An integrated mounting flange is uniformly provided on the outer periphery of one end of the cylinder body adjacent to the right end cover component. The cylinder body is connected to the output target through the mounting flange. The mounting flange has a main connecting hole extending along the axial direction of the cylinder body. The main connecting hole cooperates with the connecting screw to connect with the output target. The mounting flange also has an auxiliary threaded hole. The central axis of the auxiliary threaded hole is perpendicular to the central axis of the main connecting hole.

10. A hydraulic system, characterized in that: The actuator of the hydraulic system is a hydraulic planetary roller screw helical oscillating cylinder as described in any one of claims 1-9.

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