Rotary electric cylinder based on planetary roller screw and manufacturing method

Abstract

The invention belongs to the technical field of electric cylinders, particularly relates to a rotary electric cylinder based on a planetary roller screw and a manufacturing method, and solves the problems of insufficient lubricating efficiency and poor integration in the prior art. Comprising a planetary lead screw pair lead screw, a planetary lead screw pair nut, a guide key and a plurality of planetary lead screw pair rollers, and the planetary lead screw pair nut is in sliding connection with the planetary roller lead screw pair lead screw in the direction through the guide key. The filter screen arranged at the connecting end of the main conveying pipe can intercept particle impurities in the lubricating oil, so that the cleanliness of the oil liquid is ensured; and the tail end of the auxiliary conveying pipe adopts a flat nozzle design and is matched with a pipe diameter reducing structure, and the oil injection pressure is improved by utilizing a fluid mechanics principle, so that the lubricating oil accurately covers a meshing area of the planetary roller screw pair in a fan-shaped spraying form, a uniform oil film is formed to reduce friction, and meanwhile, the waste of the lubricating oil is avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of electric cylinders, and specifically to a rotary electric cylinder based on a planetary roller screw and a manufacturing method thereof. Background Art

[0002] At present, a rotary electric cylinder with a planetary roller screw is a device that converts the rotary motion of a servo motor into a linear motion.

[0003] In the technological evolution of planetary roller screw electric cylinders, insufficient lubrication efficiency and low system integration are the two core bottlenecks restricting their performance breakthroughs. Traditional electric cylinders generally adopt passive oil bath lubrication or single-point oil injection methods. The lubricating oil can only contact the friction pairs through gravity or a simple diversion structure, resulting in a large number of lubrication blind spots in the meshing area between the rollers and the screw. Under high-speed and heavy-load working conditions, this non-uniform lubrication state will cause local temperature rise, accelerate the wear of the gear tooth surface, reduce the transmission efficiency. At the same time, metal particles generated by the direct contact of the friction pair surface further contaminate the lubricating medium, forming a vicious cycle. More seriously, the existing lubrication system lacks a closed-loop control mechanism. When the viscosity of the oil fluctuates due to temperature changes, the system cannot automatically adjust the oil supply, resulting in coexistence of insufficient lubrication and oil waste. The problem of insufficient system integration is also prominent. The housing of traditional electric cylinders mostly adopts an integral casting structure, and the assembly of components requires positioning through non-standard tooling. This design defect is particularly fatal in the application scenarios of precision machining equipment - external oil pipes and lines are prone to interference with other parts of the machine tool, and the decentralized layout also makes fault diagnosis require one-by-one investigation, with high maintenance costs. Summary of the Invention

[0004] The purpose of the present invention is to provide a rotary electric cylinder based on a planetary roller screw and a manufacturing method thereof, which solves the problems of insufficient lubrication efficiency and poor integration.

[0005] To achieve the above purpose, the present invention provides the following technical solutions: A rotary electric cylinder based on a planetary roller screw and a manufacturing method thereof, including a servo motor as a driving source;

[0006] A planetary roller screw pair, including a planetary screw pair screw, a planetary screw pair nut, a guiding key, and a plurality of planetary screw pair rollers. The planetary screw pair nut is slidably connected to the planetary roller screw pair screw in the direction of the guiding key;

[0007] Lubrication system, including a lubricating oil tank, a fixed block, a piston block, a main delivery pipe, a secondary delivery pipe and an oil outlet valve; the lubricating oil tank is arranged on one side of the nut of the planetary screw pair, and the piston block is slidably assembled inside it through the fixed block, and the piston block is connected to the fixed block through a return spring; there are at least four main delivery pipes, one end of the main delivery pipe is directly communicated with the lubricating oil tank, and the other end branches into at least four groups of equally spaced secondary delivery pipes, and the secondary delivery pipes extend to the contact surface between the rollers and the screw of the planetary roller screw pair; there are two oil outlet valves, which are respectively installed on both sides of the servo motor, its oil outlet pipe is communicated with the lubricating oil tank, and a one-way valve is provided at the end of the oil inlet pipe;

[0008] Transmission gear set, including an output gear and a spur gear ring, a rack is provided at the bottom of the nut of the planetary screw pair, the rack meshes with the output gear, and the output gear is fixed in the electric cylinder housing through a gear bearing and a gear gland;

[0009] Support structure, including a screw support bearing, a left bearing gland and a right bearing gland, the screw support bearing is fixed at both ends of the electric cylinder housing through the left bearing gland and the right bearing gland;

[0010] Limit protection assembly, including a limit position switch and a snap ring, the limit position switch is arranged on the inner wall of the electric cylinder housing, and the snap ring is installed at the end of the nut of the planetary screw pair;

[0011] Transmission assembly, including a transmission motor, a transmission shaft, a rotating gear and a limit circular plate; the transmission motor drives the rotating gear to rotate through the transmission shaft, the rotating gear meshes with the outer gear ring of the limit circular plate, and a top block is provided on the inner top ring inner wall of the limit circular plate, and the top block abuts against the piston block.

[0012] As a preferred solution of the present invention, a filter screen is provided at the connection end of the main delivery pipe and the lubricating oil tank, an injection nozzle is provided at the end of the secondary delivery pipe, the injection nozzle faces the meshing area between the rollers and the screw of the planetary screw pair, and the diameter of the secondary delivery pipe gradually decreases along the lubricating oil flow direction.

[0013] As a preferred solution of the present invention, the rack at the bottom of the nut of the planetary screw pair is a spur gear structure, and its meshing clearance with the output gear is adjusted through a cage, and the cage is fixed to the electric cylinder housing through a lock nut.

[0014] As a preferred solution of the present invention, the screw support bearing is a double-row angular contact ball bearing, its inner ring is in interference fit with the screw of the planetary screw pair, and the outer ring is axially limited through the left bearing gland and the right bearing gland.

[0015] As a preferred solution of the present invention, a pressure sensor is provided inside the oil outlet valve, and the pressure sensor is signal-connected to the control system of the servo motor to adjust the rotation speed of the transmission motor according to the lubricating oil pressure feedback.

[0016] As a preferred embodiment of the present invention, the number of circumferentially evenly distributed groups of the main delivery pipe is at least four groups, and the auxiliary delivery pipes are fixed to the inner wall of the electric cylinder housing through fixing blocks.

[0017] As a preferred embodiment of the present invention, the limiting circular plate is axially limited by a gear gland, and the contact surface between the top block of the inner top ring and the piston block is in inclined surface fit to convert the rotary motion into the linear reciprocating motion of the piston block.

[0018] As a preferred embodiment of the present invention, the electric cylinder housing is of a split structure, including a left housing and a right housing. The left housing and the right housing are connected by bolts, and a sealing ring is provided at the connection.

[0019] A manufacturing method of a rotary swing electric cylinder based on a planetary roller screw pair includes the following steps:

[0020] S1. Component preparation: Process the planetary screw of the planetary roller screw pair, the planetary screw nut and the planetary roller according to the design requirements, and machine the sliding groove of the guiding key on the inner wall of the planetary screw nut.

[0021] S2. Assembly of the planetary roller screw pair: Axially slidably connect the planetary screw nut to the planetary screw of the planetary roller screw pair through the guiding key, and ensure that the contact surface accuracy between the roller and the screw and the nut meets the requirements of swing transmission.

[0022] S3. Installation of the lubrication system: Fix the lubricating oil tank on one side of the planetary screw nut, install a fixing block in the lubricating oil tank, and slidably assemble the piston block in the fixing block through a spring.

[0023] Connect the main delivery pipe to the bottom of the lubricating oil tank, and process at least four groups of equally spaced and circumferentially evenly distributed auxiliary delivery pipes at the end of the main delivery pipe, and extend the auxiliary delivery pipes to the contact surface between the roller and the screw of the planetary roller screw pair.

[0024] Install oil outlet valves on both sides of the servo motor, connect the oil outlet pipes of the oil outlet valves to the lubricating oil tank, and set a one-way valve at the end of the inlet pipe.

[0025] S4. Assembly of the transmission gear set: Machine a rack with a straight tooth structure at the bottom of the planetary screw nut, install the output gear in the electric cylinder housing through a gear bearing and a gear gland, and adjust the meshing clearance between the rack and the output gear.

[0026] Connect the straight tooth ring to the output gear through a spline, and fix the meshing position through a cage and a locking nut.

[0027] S5. Installation of the support structure: Press the screw support bearing into both ends of the electric cylinder housing, and axially limit it through the left bearing gland and the right bearing gland to ensure that the inner ring of the screw support bearing is in interference fit with the planetary screw of the planetary roller screw pair.

[0028] S6. Limit protection component setting: Install a limit position switch on the inner wall of the electric cylinder housing, and install a snap ring at the end of the nut of the planetary lead screw pair. Set the compression stroke of the snap ring to match the trigger threshold of the limit position switch;

[0029] S7. Transmission component integration: Fix the transmission motor on the outside of the electric cylinder housing, connect the rotating gear through a transmission shaft, and mesh the rotating gear with the external gear ring of the limit circular plate;

[0030] Machine a beveled top block on the inner top ring of the limit circular plate to make the top block abut against the piston block, and axially limit the limit circular plate through a gear gland;

[0031] S8. System debugging: Inject lubricating oil into the lubricating oil tank, start the transmission motor to drive the piston block to reciprocate, and verify the uniformity of the lubricating oil injection of the nozzle of the secondary delivery pipe;

[0032] Monitor the pressure of the oil outlet valve through a pressure sensor, and adjust the speed of the transmission motor to make the pressure of the lubrication system meet the swing working condition requirements of the planetary roller screw pair;

[0033] S9. Housing encapsulation: Connect the left housing and the right housing of the electric cylinder housing through bolts, and install a sealing ring at the connection to complete the assembly of the rotary swing electric cylinder.

[0034] As a preferred solution of the present invention, a filter screen is installed at the connection end of the main delivery pipe and the lubricating oil tank, and a nozzle is machined at the end of the secondary delivery pipe. The nozzle faces the meshing area of the roller and the lead screw of the planetary roller screw pair, and the diameter of the secondary delivery pipe gradually decreases in a taper of 3°-5° along the lubricating oil flow direction to enhance the atomization effect of the lubricating oil through the Venturi effect.

[0035] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0036] 1. Through the settings of structures such as the main delivery pipe and the filter screen, and the secondary delivery pipe and the nozzle, the filter screen installed at the connection end of the main delivery pipe can intercept particulate impurities in the lubricating oil to ensure the cleanliness of the oil; the end of the secondary delivery pipe adopts a flat nozzle design, combined with the structure of gradually decreasing diameter, and uses the principle of fluid mechanics to increase the injection pressure of the lubricating oil, so that the lubricating oil accurately covers the meshing area of the planetary roller screw pair in the form of a fan-shaped spray, forming a uniform oil film to reduce friction and avoid waste of lubricating oil at the same time.

[0037] 2. Through the settings of a split housing, an embedded flow channel, a fixing block, and an interference fit, etc., the electric cylinder housing is designed in a split manner. The left and right housings are connected by bolts and provided with sealing rings, facilitating the rapid assembly and maintenance of components; the lubricating oil circulation flow channel is directly machined on the inner wall of the housing, and the auxiliary delivery pipe is fastened in the flow channel through a fixing block, reducing the space occupied by external pipelines. At the same time, the fixing block and the housing adopt an interference fit to prevent the loosening of the pipeline caused by vibration. The overall structure is compact and has excellent anti-vibration performance. Brief Description of the Drawings

[0038] Figure 1 is the overall structural schematic diagram of the present invention;

[0039] Figure 2 is the internal structural schematic diagram of the electric cylinder housing of the present invention;

[0040] Figure 3 is the transmission structural schematic diagram of the present invention;

[0041] Figure 4 is the overall structural schematic diagram of the oil outlet valve delivery of the present invention;

[0042] Figure 5 is the overall structural schematic diagram of the roller of the planetary ball screw pair of the present invention;

[0043] Figure 6 is the overall structural schematic diagram of the oil outlet valve of the present invention;

[0044] Figure 7 is the internal transmission structural schematic diagram of the lubricating oil tank of the present invention;

[0045] Figure 8 is of the present invention Figure 7 enlarged view of the label A in.

[0046] In the figure: 1. Servo motor; 2. Locking nut; 3. Screw support bearing; 4. Right bearing gland; 5. Cage; 6. Snap ring; 7. Straight tooth ring gear; 8. Limit position switch; 9. Planetary ball screw pair nut; 10. Guide key; 11. Planetary ball screw pair roller; 12. Planetary roller screw pair screw; 13. Electric cylinder housing; 14. Left bearing gland; 15. Output gear; 16. Gear bearing; 17. Gear gland; 18. Lubricating oil tank; 180. Fixing block; 181. Main delivery pipe; 1811. Auxiliary delivery pipe; 182. Transmission motor; 1821. Transmission shaft; 1822. Rotating gear; 183. Limit circular plate; 1831. External gear ring; 1832. Inner top ring; 184. Piston block; 1841. Rebound spring; 19. Oil outlet valve; 191. Inlet pipe; 192. Check valve; 193. Pressure sensor; 194. Outlet pipe. Detailed Embodiment

[0047] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0048] Please refer to Figures 1-8 , in this embodiment, a rotary electric cylinder based on a planetary roller screw and its manufacturing method include

[0049] A servo motor 1, as a driving source;

[0050] A planetary roller screw pair, including a planetary screw pair screw, a planetary screw pair nut 9, a guiding key 10, and a plurality of planetary screw pair rollers 11. The planetary screw pair nut 9 is slidably connected in the direction of the planetary roller screw pair screw 12 through the guiding key 10;

[0051] A lubrication system, including a lubricating oil tank 18, a fixing block 180, a piston block 184, a main delivery pipe 181, a sub-delivery pipe 1811, and an oil outlet valve 19; the lubricating oil tank 18 is arranged on one side of the planetary screw pair nut 9, and a piston block 184 is slidably assembled inside it through a fixing block 180. The piston block 184 is connected to the fixing block 180 through a return spring 1841 by a spring; there are at least four main delivery pipes 181. One end of the main delivery pipe 181 is directly communicated with the lubricating oil tank 18, and the other end branches into at least four groups of equally spaced and uniformly distributed sub-delivery pipes 1811. The sub-delivery pipes 1811 extend to the contact surface between the rollers and the screw of the planetary roller screw pair; there are two oil outlet valves 19, which are respectively installed on both sides of the servo motor 1. Its oil outlet pipe 194 is communicated with the lubricating oil tank 18, and a one-way valve 192 is provided at the end of the oil inlet pipe 191;

[0052] A transmission gear set, including an output gear 15 and a spur gear ring 7. A rack is provided at the bottom of the planetary screw pair nut 9, and the rack meshes with the output gear 15. The output gear 15 is fixed in the electric cylinder housing 13 through a gear bearing 16 and a gear gland 17;

[0053] A support structure, including a screw support bearing 3, a left bearing gland 14, and a right bearing gland 4. The screw support bearing 3 is fixed at both ends of the electric cylinder housing 13 through the left bearing gland 14 and the right bearing gland 4;

[0054] A limit protection assembly, including a limit position switch 8 and a snap ring 6. The limit position switch 8 is arranged on the inner wall of the electric cylinder housing 13, and the snap ring 6 is installed at the end of the planetary screw pair nut 9;

[0055] The transmission assembly includes a transmission motor 182, a transmission shaft 1821, a rotating gear 1822, and a limiting circular plate 183; the transmission motor 182 drives the rotating gear 1822 to rotate through the transmission shaft 1821, the rotating gear 1822 meshes with the external tooth ring 1831 of the limiting circular plate 183, and a top block is provided on the inner wall of the inner top ring 1832 of the limiting circular plate 183, and the top block abuts against the piston block 184.

[0056] Specifically, the servo motor 1 serves as a driving source and transmits torque to the lead screw of the planetary roller screw pair through a coupling to drive it to rotate around the axis. The nut 9 of the planetary screw pair forms a helical transmission pair with the lead screw through the guide key 10. When the lead screw rotates, the nut moves linearly along the axial direction. The lubrication system stores lubricating oil through the lubricating oil tank 18. The piston block 184 reciprocally slides along the inner wall of the fixed block 180 under the action of the return spring 1841 to press the lubricating oil into the main delivery pipe 181. The main delivery pipe 181 diverts the lubricating oil to multiple groups of sub-delivery pipes 1811, and the nozzles at the ends of the sub-delivery pipes 1811 are aligned with the contact surfaces between the rollers and the lead screw of the planetary roller screw pair to form a lubricating oil film to reduce friction. In the transmission gear set, the straight tooth rack at the bottom of the nut meshes with the output gear 15 to convert the linear motion of the nut into the rotational motion of the gear. The output gear 15 is supported in the electric cylinder housing 13 through the gear bearing 16 and drives the straight tooth ring 7 to rotate synchronously. In the support structure, both ends of the lead screw are supported by double-row angular contact ball bearings. The inner ring of the bearing is interference-fitted with the lead screw, and the outer ring is axially fixed by the left and right bearing retainers 4 to ensure the rotational accuracy of the lead screw. In the limit protection assembly, the spring retainer 6 is installed at the end of the nut. When the nut moves to the limit position, it triggers the limit position switch 8 to cut off the power supply of the servo motor 1. In the transmission assembly, the transmission motor 182 drives the rotating gear 1822 to rotate. The rotating gear 1822 meshes with the external tooth ring 1831 of the limiting circular plate 183, and the inclined surface top block of the inner top ring 1832 of the limiting circular plate 183 pushes the piston block 184 to perform reciprocating linear motion to achieve the periodic supply of lubricating oil.

[0057] In this embodiment, a filter screen is provided at the connection end between the main delivery pipe 181 and the lubricating oil tank 18, and a nozzle is provided at the end of the sub-delivery pipe 1811. The nozzle faces the meshing area between the rollers and the lead screw of the planetary screw pair roller 11, and the diameter of the sub-delivery pipe 1811 gradually decreases along the lubricating oil flow direction.

[0058] Specifically, on the basis of Claim 1, a filter screen is provided at the connection between the main delivery pipe 181 of the lubrication system and the lubricating oil tank 18 to intercept particulate impurities in the lubricating oil. The main delivery pipe 181 branches into multiple groups of sub-delivery pipes 1811, and each group of sub-delivery pipes 1811 is evenly distributed along the inner wall circumference of the electric cylinder housing 13. The end nozzle adopts a flat nozzle design, so that the lubricating oil covers the contact area between the rollers and the lead screw of the planetary roller screw pair in the form of a fan-shaped spray. The diameter of the sub-delivery pipe 1811 gradually decreases along the lubricating oil flow direction, and the hydrodynamic principle is used to increase the injection pressure to ensure that the lubricating oil fully penetrates into the meshing clearance. The multiple groups of sub-delivery pipes 1811 are fastened to the inner wall of the housing by fixing blocks 180, and an interference fit is adopted between the fixing blocks 180 and the housing to prevent the pipeline from loosening caused by vibration.

[0059] In this embodiment, the rack at the bottom of the nut 9 of the planetary screw pair is a straight-tooth structure, and its meshing clearance with the output gear 15 is adjusted by the cage 5. The cage 5 is fixed to the electric cylinder housing 13 by a lock nut 2.

[0060] Specifically, the straight-tooth rack at the bottom of the nut 9 of the planetary screw pair forms an external meshing transmission pair with the output gear 15, and the rack module is the same as the gear module to ensure the meshing overlap ratio. By adjusting the axial position of the cage 5, the meshing clearance between the rack and the gear can be finely adjusted. The cage 5 is fixed to the electric cylinder housing 13 by a lock nut 2 to prevent axial movement during the transmission process. When the nut moves linearly, the rack drives the output gear 15 to rotate, and the output gear 15 is connected to the straight-tooth ring 7 through a spline to transmit torque to the ring gear. An annular seal groove is provided on the outer circle of the straight-tooth ring 7 to form a dynamic seal with the inner wall of the housing to prevent the lubricating oil from leaking into the gear transmission area.

[0061] In this embodiment, the lead screw support bearing 3 is a double-row angular contact ball bearing, the inner ring of which is in interference fit with the lead screw of the planetary screw pair, and the outer ring is axially limited by the left bearing cover 14 and the right bearing cover 4.

[0062] Specifically, the lead screw support bearing 3 adopts a double-row angular contact ball bearing, the inner ring of which is in interference fit with the lead screw, and the outer ring is axially limited by the left and right bearing covers 4. The left and right bearing covers 4 are in contact with the end face of the electric cylinder housing 13, and a stepped structure is provided in the inner hole of the cover to apply an axial preload to the outer ring of the bearing. The shaft shoulders at both ends of the lead screw are in contact with the end face of the inner ring of the bearing to form axial positioning. When installing the bearing, by adjusting the thickness of the gasket between the cover and the housing, the bearing clearance can be compensated to ensure the rotation accuracy of the lead screw. A skeleton oil seal is provided on the outside of the right bearing cover 4 to form a lip seal with the lead screw to prevent the grease from leaking out.

[0063] In this embodiment, a pressure sensor 193 is provided inside the oil outlet valve 19, and the pressure sensor 193 is signal-connected to the control system of the servo motor 1 to adjust the rotation speed of the drive motor 182 according to the lubricating oil pressure feedback.

[0064] Specifically, a pressure sensor 193 is integrated inside the fuel outlet valve 19 to monitor the lubricating oil pressure in real time. When the system pressure is lower than the set threshold, the pressure sensor 193 outputs an electrical signal to the control system of the servo motor 1, and the control system adjusts the rotation speed of the drive motor 182 through a frequency converter to drive the lubrication system to increase pressure. The valve body of the fuel outlet valve 19 adopts a split structure, the valve core and the valve seat are sealed through a conical surface, and the valve rod achieves dynamic sealing through a bellows. The one-way valve 192 at the end of the oil inlet pipe 191 adopts a spring-loaded valve core, which only allows the lubricating oil to flow from the fuel tank to the main delivery pipe 181, preventing the backflow of oil caused by system pressure fluctuations.

[0065] In this embodiment, the number of circumferentially evenly distributed groups of the main delivery pipe 181 is at least four groups, and the auxiliary delivery pipe 1811 is fixed to the inner wall of the electric cylinder housing 13 through a fixing block 180.

[0066] Specifically, the main delivery pipe 181 branches into four groups of auxiliary delivery pipes 1811, and each group of auxiliary delivery pipes 1811 is circumferentially evenly distributed at 90° along the inner wall of the electric cylinder housing 13. The auxiliary delivery pipe 1811 is fixed in the spiral flow channel of the housing through a fixing block 180, and the fixing block 180 and the housing are connected by threads to ensure the stability of the pipeline position. The auxiliary delivery pipe 1811 adopts a flexible metal hose, which can adapt to the vibration and deformation during the movement of the electric cylinder. The outlet direction of the fuel injection nozzle is consistent with the normal direction of the contact surface of the planetary roller screw pair, ensuring that the lubricating oil is vertically sprayed onto the meshing area to form a uniform oil film.

[0067] In this embodiment, the limiting circular plate 183 is axially limited by the gear gland 17, and the contact surface between the top block of the inner top ring 1832 and the piston block 184 is a bevel fit to convert the rotational motion into the linear reciprocating motion of the piston block 184.

[0068] Specifically, the limiting circular plate 183 is axially fixed to the electric cylinder housing 13 through the gear gland 17. The gear gland 17 and the housing are connected by screws and provided with lock washers. The inclined surface top block of the inner top ring 1832 of the limiting circular plate 183 forms a wedge fit with the end face of the piston block 184. When the drive motor 182 drives the rotating gear 1822 to rotate, the limiting circular plate 183 drives the top block to make a circular motion, and the inclined surface of the top block pushes the piston block 184 to make a linear reciprocating motion along the inner wall of the fixing block 180. The movement stroke of the piston block 184 is controlled by the number of teeth of the outer gear ring 1831 of the limiting circular plate 183 to ensure that the lubricating oil supply matches the system demand.

[0069] In this embodiment, the electric cylinder housing 13 is of a split structure, including a left housing and a right housing. The left housing and the right housing are connected by bolts, and a sealing ring is provided at the connection.

[0070] Specifically, the electric cylinder housing 13 adopts a split design. The left and right housings are connected by bolts, and a rectangular sealing ring is arranged on the connection surface. The cross-section of the sealing ring forms an interference fit with the sealing groove of the housing. The inner wall of the housing is machined with a lubricating oil circulation flow channel. The cross-section of the flow channel is semi-circular. The inlet of the flow channel is connected to the auxiliary delivery pipe 1811, and the outlet is communicated with the oil return port of the lubricating oil tank 18 to form a closed-loop lubrication system. The surface of the flow channel is polished to reduce the flow resistance of the lubricating oil. The parting surface of the left and right housings avoids the transmission gear set and the planetary roller screw pair, which is convenient for the assembly and maintenance of components.

[0071] A manufacturing method of a rotary swing electric cylinder based on a planetary roller screw pair includes the following steps:

[0072] S1. Component preparation: Machine the planetary screw of the planetary roller screw pair, the nut 9 of the planetary screw pair and the roller 11 of the planetary screw pair according to the design requirements, and machine the sliding groove of the guiding key 10 on the inner wall of the nut 9 of the planetary screw pair;

[0073] S2. Assembly of the planetary roller screw pair: Axially slidably connect the nut 9 of the planetary screw pair with the planetary screw through the guiding key 10 to ensure that the contact surface accuracy between the roller and the screw and the nut meets the requirements of swing transmission;

[0074] S3. Installation of the lubrication system: Fix the lubricating oil tank 18 on one side of the nut 9 of the planetary screw pair, install the fixing block 180 in the lubricating oil tank 18, and slidably assemble the piston block 184 in the fixing block 180 through a spring;

[0075] Connect the main delivery pipe 181 to the bottom of the lubricating oil tank 18, and at the end of the main delivery pipe 181, bifurcate and machine at least four groups of equally spaced auxiliary delivery pipes 1811, and extend the auxiliary delivery pipes 1811 to the contact surface between the roller and the screw of the planetary roller screw pair;

[0076] Install the oil outlet valves 19 on both sides of the servo motor 1, connect the oil outlet pipe 194 of the oil outlet valve 19 to the lubricating oil tank 18, and set a one-way valve 192 at the end of the oil inlet pipe 191;

[0077] S4. Assembly of the transmission gear set: Machine a rack with a straight tooth structure at the bottom of the nut 9 of the planetary screw pair, install the output gear 15 in the electric cylinder housing 13 through the gear bearing 16 and the gear gland 17, and adjust the meshing clearance between the rack and the output gear 15;

[0078] Connect the straight tooth ring 7 and the output gear 15 through a spline, and fix the meshing position through the cage 5 and the locking nut 2;

[0079] S5. Installation of the support structure: Press the screw support bearing 3 into both ends of the electric cylinder housing 13, and axially limit it through the left bearing gland 14 and the right bearing gland 4 to ensure that the inner ring of the screw support bearing 3 has an interference fit with the planetary screw of the planetary screw pair;

[0080] S6. Limit protection component setting: Install a limit position switch 8 on the inner wall of the electric cylinder housing 13, and install a snap ring 6 at the end of the nut 9 of the planetary ball screw pair. Set the compression stroke of the snap ring 6 to match the trigger threshold of the limit position switch 8;

[0081] S7. Transmission component integration: Fix the transmission motor 182 on the outside of the electric cylinder housing 13, connect the rotating gear 1822 through the transmission shaft 1821, and mesh the rotating gear 1822 with the external gear ring 1831 of the limit circular plate 183;

[0082] Machine a beveled top block on the inner top ring 1832 of the limit circular plate 183 to make the top block abut against the piston block 184, and axially limit the limit circular plate 183 through the gear gland 17;

[0083] S8. System debugging: Inject lubricating oil into the lubricating oil tank 18, start the transmission motor 182 to drive the piston block 184 to reciprocate, and verify the uniformity of the lubricating oil injection of the nozzle of the auxiliary delivery pipe 1811;

[0084] Monitor the pressure of the oil outlet valve 19 through the pressure sensor 193, and adjust the rotation speed of the transmission motor 182 so that the pressure of the lubrication system meets the swing working condition requirements of the planetary roller screw pair;

[0085] S9. Housing encapsulation: Connect the left housing and the right housing of the electric cylinder housing 13 through bolts, and install a sealing ring at the connection to complete the assembly of the rotary swing electric cylinder.

[0086] Specifically, in step 3, install a filter screen at the connection end of the main delivery pipe 181 and the lubricating oil tank 18. Machine a nozzle at the end of the auxiliary delivery pipe 1811. The nozzle faces the meshing area of the rollers and the screw of the planetary roller screw pair, and the diameter of the auxiliary delivery pipe 1811 gradually decreases at a taper of 3° - 5° along the lubricating oil flow direction to enhance the atomization effect of the lubricating oil through the Venturi effect.

[0087] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A rotary electric cylinder based on a planetary roller screw, characterized in that, Comprising: A servo motor (1), serving as a driving source; A planetary roller screw pair, including a planetary screw pair screw, a planetary screw pair nut (9), a guiding key (10), and multiple planetary screw pair rollers (11). The planetary screw pair nut (9) is slidably connected in the direction of the planetary roller screw pair screw (12) through the guiding key (10); A lubrication system, including a lubricating oil tank (18), a fixing block (180), a piston block (184), a main delivery pipe (181), a sub-delivery pipe (1811), and an oil outlet valve (19). The lubricating oil tank (18) is arranged on one side of the planetary screw pair nut (9), and a piston block (184) is slidably assembled inside it through the fixing block (180). The piston block (184) is connected to the fixing block (180) through a return spring (1841). One end of the main delivery pipe (181) is directly communicated with the lubricating oil tank (18). There are at least four main delivery pipes (181), and the other end branches into at least four groups of equally spaced sub-delivery pipes (1811). The sub-delivery pipes (1811) extend to the contact surface between the rollers and the screw of the planetary roller screw pair. There are two oil outlet valves (19), which are respectively installed on both sides of the servo motor (1). Its oil outlet pipe (194) is communicated with the lubricating oil tank (18), and a check valve (192) is provided at the end of the oil inlet pipe (191); A transmission gear set, including an output gear (15) and a straight-tooth gear ring (7). A rack is provided at the bottom of the planetary screw pair nut (9), and the rack meshes with the output gear (15). The output gear (15) is fixed inside the electric cylinder housing (13) through a gear bearing (16) and a gear gland (17); A support structure, including a screw support bearing (3), a left bearing gland (14), and a right bearing gland (4). The screw support bearing (3) is fixed at both ends of the electric cylinder housing (13) through the left bearing gland (14) and the right bearing gland (4); A limit protection assembly, including a limit position switch (8) and a snap ring (6). The limit position switch (8) is arranged on the inner wall of the electric cylinder housing (13), and the snap ring (6) is installed at the end of the planetary screw pair nut (9); A transmission component, including a transmission motor (182), a transmission shaft (1821), a rotating gear (1822), and a limit circular plate (183). The transmission motor (182) drives the rotating gear (1822) to rotate through the transmission shaft (1821). The rotating gear (1822) meshes with the outer gear ring (1831) of the limit circular plate (183). A top block is provided on the inner wall of the inner top ring (1832) of the limit circular plate (183), and the top block abuts against the piston block (184).

2. The rotary electric cylinder according to claim 1, characterized in that: A filter screen is provided at the connection end of the main delivery pipe (181) and the lubricating oil tank (18). An injection nozzle is provided at the end of the sub-delivery pipe (1811). The injection nozzle faces the meshing area between the rollers and the screw of the planetary screw pair rollers (11), and the diameter of the sub-delivery pipe (1811) gradually decreases along the lubricating oil flow direction.

3. The rotary electric cylinder according to claim 1, characterized in that: The rack at the bottom of the nut (9) of the planetary ball screw pair has a straight tooth structure, and its meshing clearance with the output gear (15) is adjusted by the cage (5). The cage (5) is fixed to the electric cylinder housing (13) by a lock nut (2).

4. The rotary electric cylinder according to claim 1, wherein: The screw support bearing (3) is a double-row angular contact ball bearing. Its inner ring has an interference fit with the screw of the planetary ball screw pair, and the outer ring is axially limited by the left bearing cover (14) and the right bearing cover (4).

5. The rotary electric cylinder according to claim 1, characterized in that: A pressure sensor (193) is provided inside the oil outlet valve (19). The pressure sensor (193) is signal-connected to the control system of the servo motor (1) to adjust the speed of the drive motor (182) according to the feedback of the lubricating oil pressure.

6. The rotary electric cylinder according to claim 1, wherein: The number of circumferentially evenly distributed groups of the main delivery pipe (181) is at least four groups, and the auxiliary delivery pipe (1811) is fixed to the inner wall of the electric cylinder housing (13) by a fixing block (180).

7. The rotary electric cylinder according to claim 1, characterized in that: The limiting circular plate (183) is axially limited by the gear cover (17). The contact surface between the top block of the inner top ring (1832) and the piston block (184) is in inclined surface fit to convert the rotary motion into the linear reciprocating motion of the piston block (184).

8. The rotary electric cylinder according to claim 1, characterized in that: The electric cylinder housing (13) is of a split structure, including a left housing and a right housing. The left housing and the right housing are connected by bolts, and a sealing ring is provided at the connection.

9. A manufacturing method of a rotary and oscillating electric cylinder based on a planetary roller screw pair, characterized in that, It includes the following steps: S1. Component preparation: Machine the screw of the planetary ball screw pair, the nut (9) of the planetary ball screw pair and the rollers (11) of the planetary ball screw pair according to the design requirements, and machine the sliding groove of the guide key (10) on the inner wall of the nut (9) of the planetary ball screw pair; S2. Assembly of the planetary ball screw pair: Axially slidably connect the nut (9) of the planetary ball screw pair to the screw of the planetary ball screw pair through the guide key (10) to ensure that the contact surface accuracy between the rollers and the screw and the nut meets the requirements of oscillating transmission; S3. Installation of the lubrication system: Fix the lubricating oil tank (18) on one side of the nut (9) of the planetary ball screw pair. Install a fixing block (180) in the lubricating oil tank (18), and slidably assemble the piston block (184) into the fixing block (180) through a spring; Connect the main delivery pipe (181) to the bottom of the lubricating oil tank (18), and machine at least four groups of equally spaced and evenly distributed auxiliary delivery pipes (1811) at the end of the main delivery pipe (181), and extend the auxiliary delivery pipes (1811) to the contact surface between the rollers and the screw of the planetary ball screw pair; Install oil outlet valves (19) on both sides of the servo motor (1), connect the oil outlet pipe (194) of the oil outlet valve (19) to the lubricating oil tank (18), and set a check valve (192) at the end of the inlet pipe (191); S4. Assembly of the transmission gear set: Machine a rack with a straight tooth structure at the bottom of the nut (9) of the planetary ball screw pair. Install the output gear (15) in the electric cylinder housing (13) through the gear bearing (16) and the gear cover (17), and adjust the meshing clearance between the rack and the output gear (15); Connect the straight tooth ring (7) and the output gear (15) by a spline, and fix the meshing position through the cage (5) and the lock nut (2); S5. Installation of the support structure: Press the lead screw support bearings (3) into both ends of the electric cylinder housing (13), and axially limit them through the left bearing gland (14) and the right bearing gland (4) to ensure an interference fit between the inner ring of the lead screw support bearing (3) and the lead screw of the planetary lead screw pair. S6. Setting of the limit protection component: Install the limit position switch (8) on the inner wall of the electric cylinder housing (13), and install a snap ring (6) at the end of the nut (9) of the planetary lead screw pair. Set the compression stroke of the snap ring (6) to match the trigger threshold of the limit position switch (8). S7. Integration of the transmission component: Fix the transmission motor (182) on the outside of the electric cylinder housing (13), connect the rotating gear (1822) through the transmission shaft (1821), and mesh the rotating gear (1822) with the external gear ring (1831) of the limit circular plate (183). Machine a beveled block on the inner top ring (1832) of the limit circular plate (183) so that the block abuts against the piston block (184), and axially limit the limit circular plate (183) through the gear gland (17). S8. System debugging: Inject lubricating oil into the lubricating oil tank (18), start the transmission motor (182) to drive the piston block (184) to reciprocate, and verify the uniformity of the lubricating oil injection of the nozzle of the auxiliary delivery pipe (1811). Monitor the pressure of the oil outlet valve (19) through the pressure sensor (193), and adjust the rotation speed of the transmission motor (182) so that the lubrication system pressure meets the swing working condition requirements of the planetary roller screw pair. S9. Housing encapsulation: Connect the left housing and the right housing of the electric cylinder housing (13) by bolts, and install a sealing ring at the connection to complete the assembly of the rotary swing electric cylinder.

10. The manufacturing method according to claim 9, characterized in that: In step 3, install a filter screen at the connection end of the main delivery pipe (181) and the lubricating oil tank (18), machine a nozzle at the end of the auxiliary delivery pipe (1811), the nozzle faces the meshing area between the rollers and the lead screw of the planetary roller screw pair, and the diameter of the auxiliary delivery pipe (1811) gradually decreases in a 3° - 5° taper along the lubricating oil flow direction to enhance the atomization effect of the lubricating oil through the Venturi effect.

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