Skin stretching hydraulic control device
By using a hydraulically controlled device for precise and flexible stretching, the problems of overstretching and springback during the skin stretching process are solved, thereby improving the skin forming quality and yield rate.
Patent Information
- Application Number
- CN202511546170.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-28
- Publication Date
- 2026-01-23
AI Technical Summary
Traditional skin stretching and forming processes are prone to overstretching, leading to cracking, large springback, and numerous surface defects, which affect the aerodynamic performance of aircraft.
A skin stretching hydraulic control device is adopted, which drives the follow-up mechanism and jaw assembly through a hydraulic power station, combined with servo motor pump group and proportional valve control, to achieve precise and flexible skin stretching. It is equipped with dual-axis tilt sensor and displacement sensor to ensure stretching accuracy.
It improved the quality and yield of skin stretching, reduced cracking and springback, and enhanced forming quality.
Smart Images
Figure CN121373157A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of aircraft skin processing technology, and in particular to a hydraulic control device for skin stretching. Background Technology
[0002] Skin stretch forming is a metal plastic forming process that uses a stretching device to apply a force field to induce plastic deformation in a metal sheet, thereby creating curved skins. This technology is widely used in the aerospace field to manufacture hyperbolic aluminum alloy skin parts for aircraft nose and tail sections, and its forming quality directly affects the aerodynamic performance of the aircraft. Traditional processing methods often result in overstretching of the skin, leading to cracking, and also suffer from problems such as high springback and numerous surface defects. Summary of the Invention
[0003] The purpose of this invention is to provide a hydraulic control device for skin stretching, which performs precise and flexible hammering and stretching of the skin, thereby improving the quality of skin stretching and greatly increasing the pass rate.
[0004] This invention is achieved by the following technical solution: A hydraulic control device for skin stretching includes a main frame, stretching cylinders, a follower mechanism, a jaw bracket, a jaw assembly, and a hydraulic power station. A jaw follower plate is mounted on the jaw bracket. A jaw assembly is mounted on the jaw follower plate. A set of stretching cylinders is located below the jaw bracket. The bottom of the set of stretching cylinders is fixed to a base plate inside the main frame. The follower mechanism is fixed to the jaw bracket, and a pitch cylinder in the follower mechanism is movably connected to the follower plate. The set of follower mechanisms lifts the follower plate via the pitch cylinder. The follower plate is connected to the jaw bracket via a rotating connecting shaft. The stretching cylinder and the pitch cylinder are connected to the hydraulic power station.
[0005] Furthermore, the follow-up mechanism includes a pitch connecting block, a pitch cylinder, a bracket, a bracket docking plate, a pitch cylinder fixing plate, and a pitch cylinder connecting frame; a set of brackets are connected and fixed through the bracket docking plate; a pitch cylinder fixing plate is provided on the bracket docking plate; a pitch cylinder connecting frame is installed on the pitch cylinder fixing plate; the piston rod end of the pitch cylinder is movably connected to the pitch connecting block, and the cylinder bottom of the pitch cylinder is movably connected to the pitch cylinder connecting frame.
[0006] Furthermore, a bracket mounting plate is fixed to the top of the bracket; an opening groove is provided on the bottom plane of the jaw bracket; the bracket mounting plate is fixedly installed in the opening groove; and a dual-axis tilt sensor is provided on the lower surface of the follower plate.
[0007] Furthermore, the jaw assembly comprises multiple jaw units, each jaw unit including an upper cover plate, a piston, a guide block, a lower pad block, a jaw cylinder body, and an upper pad block; the jaw cylinder body has a piston chamber; a piston is disposed in the piston chamber, and an upper cover plate is disposed on top of the piston chamber; the upper pad block is disposed below the piston; the lower pad block is disposed directly below the upper pad block; a guide block is disposed on the side of the jaw cylinder body; a pressure sensor is also disposed in the piston chamber; the hydraulic power station controls the piston's movement position and speed through a servo motor pump unit and an electromagnetic switch valve.
[0008] Furthermore, the upper surface of the upper pad is provided with a displacement detector facing the piston; the cylinder body of the jaw cylinder is provided with a set of oil ports; the upper and lower chambers between the piston and the piston chamber are respectively connected to a set of oil ports; the set of oil ports is connected to the hydraulic power station.
[0009] Furthermore, the main frame includes a frame body and a base plate; the upper surface of the frame body is symmetrically provided with actuator mounting grooves, and the center of the upper surface is provided with a central guide post connection through hole; the lower surface of the frame body is fixedly connected to the base plate; a lubrication cylinder mounting cavity is provided below the central guide post connection through hole; the part where the frame body connects to the base plate is provided with reinforcing ribs; the front of the frame body is provided with multiple first pipeline connection through holes, and the two sides of the front of the frame body are provided with two second pipeline connection through holes; triangular plates are welded to the adjacent connecting walls inside the frame body.
[0010] Furthermore, a guide post assembly is installed in the lubrication cylinder mounting cavity; the guide post assembly includes an intermediate guide post, a flange, and a lubrication cylinder; the lubrication cylinder is fixed in the lubrication cylinder mounting cavity by the flange; the intermediate guide post passes through the lubrication cylinder and is fixedly connected to the bottom of the jaw bracket.
[0011] Furthermore, the bracket is fixedly installed in the opening slot after passing through the actuator mounting slot; the pitch cylinder is set inside the frame body; and the tension cylinder is hinged to the bottom of the jaw bracket after passing through the actuator mounting slot.
[0012] Furthermore, a displacement sensor is installed in the stretching cylinder; the hydraulic power station controls the flow rate of the stretching cylinder and the flow direction of the hydraulic oil through a servo motor pump set and a proportional valve.
[0013] Furthermore, the lower surface of the lower pad and the upper surface of the upper pad are provided with corresponding reverse teeth that are opposite to the stretching direction of the skin.
[0014] The beneficial effects of this invention are as follows: This invention uses a hydraulic power station to drive a follower mechanism to connect the jaw assembly and the jaw bracket. The pitch cylinder in the follower mechanism is controlled by a solenoid valve for pre-stretching. Then, based on the force and direction of the skin on the jaw assembly, the follower mechanism lifts the jaw assembly through a follower plate, causing the jaw assembly to strike and stretch the skin. The stretching cylinder is equipped with a proportional valve and a displacement sensor. A dual-axis tilt sensor is installed on the follower plate. The stretching force of the stretching cylinder can be set by the proportional valve. Thus, under the drive of the hydraulic power station and the servo motor pump group, precise and flexible stretching of the skin can be achieved, ensuring the stretching accuracy and thus improving the quality of skin stretching and greatly increasing the pass rate. Attached Figure Description
[0015] Figure 1 This is a schematic diagram of the overall three-dimensional structure of the present invention; Figure 2 This is a connection diagram of the left view of the present invention (the state when the jaw follower plate is lifted by the follower mechanism); Figure 3 A schematic diagram showing the connection between the tension cylinder and the guide post assembly and the jaw bracket and jaw follower plate, respectively (the state after removing the main frame and jaw assembly). Figure 4 This is a schematic diagram of the servo mechanism; Figure 5 This is a schematic diagram of the jaw unit. Figure 6 A schematic diagram of the three-dimensional structure of the main frame.
[0016] The components include: main frame 1; frame body 11; reinforcing rib 12; first pipeline connection through hole 13; second pipeline connection through hole 14; lubrication cylinder mounting cavity 15; intermediate guide post connection through hole 16; actuator mounting groove 17; triangular plate 18; and base plate 19. 2. Extension cylinder; Follow-up mechanism 3; pitch connecting block 31; pitch cylinder 32; bracket mounting plate 33; bracket 34; bracket docking plate 35; pitch cylinder fixing plate 36; pitch cylinder connecting frame 37; Jaw support 4; Jaw follower plate 5; Jaw assembly 6; upper cover plate 61; piston 62; piston chamber 63; guide block 64; lower pad block 65; jaw cylinder body 66; upper pad block 67; oil port 68; displacement detector 69; Guide post assembly 7; intermediate guide post 71; flange 72; lubrication cylinder 73; Rotate connecting shaft 8. Detailed Implementation
[0017] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.
[0018] like Figures 1 to 6 As shown, a hydraulic control device for skin stretching includes a main frame 1, stretching cylinders 2, a follower mechanism 3, a jaw bracket 4, a jaw assembly 6, and a hydraulic power station. A jaw follower plate 5 is mounted on the jaw bracket 4. The jaw assembly 6 is mounted on the jaw follower plate 5. A set of stretching cylinders 2 is located below the jaw bracket 4. The bottom of the set of stretching cylinders 2 is fixed to a base plate 19 inside the main frame 1. The follower mechanism 3 is fixed to the jaw bracket 4. A pitch cylinder 32 in the follower mechanism 3 is movably connected to the follower plate 5, and the set of follower mechanisms 3 lifts the follower plate 5 through the pitch cylinder 32. The follower plate 5 is connected to the jaw bracket 4 via a rotating connecting shaft 8. The stretching cylinders 2 and pitch cylinder 32 are connected to the hydraulic power station.
[0019] In a preferred embodiment, the follower mechanism 3 includes a pitch connecting block 31, a pitch cylinder 32, a bracket 34, a bracket docking plate 35, a pitch cylinder fixing plate 36, and a pitch cylinder connecting frame 37; a set of brackets 34 are connected and fixed through the bracket docking plate 35; a pitch cylinder fixing plate 36 is provided on the bracket docking plate 35; a pitch cylinder connecting frame 37 is installed on the pitch cylinder fixing plate 36; the piston rod end of the pitch cylinder 32 is movably connected to the pitch connecting block 31, and the cylinder bottom of the pitch cylinder 32 is movably connected to the pitch cylinder connecting frame 37.
[0020] In a preferred embodiment, a bracket mounting plate 33 is fixed to the top of the bracket 34; an opening groove is provided on the bottom plane of the jaw bracket 4; the bracket mounting plate 33 is fixedly installed in the opening groove; and a dual-axis tilt sensor is provided on the lower surface of the follower plate 5.
[0021] In a preferred embodiment, the jaw assembly 6 comprises multiple jaw units, each including an upper cover plate 61, a piston 62, a guide block 64, a lower pad block 65, a jaw cylinder body 66, and an upper pad block 67. The jaw cylinder body 66 contains a piston chamber 63; the piston 62 is housed within the piston chamber 63, and the upper cover plate 61 is positioned above the piston chamber 63. The upper pad block 67 is positioned below the piston 62; the lower pad block 65 is positioned directly below the upper pad block 67. A guide block 64 is provided on the side of the jaw cylinder body 66, serving to support and guide the skin during stretching. The guide block 64 is made of 40Cr material (HRC36-39), exhibiting high hardness and wear resistance. A pressure sensor is also provided in the piston chamber 63. The hydraulic power station controls the movement position and speed of the piston 62 via a servo motor pump unit and an electromagnetic switch valve.
[0022] In a preferred embodiment, the upper surface of the upper pad 67 is provided with a displacement detector 69 facing the piston 62; the cylinder body 66 of the jaw cylinder is provided with a set of oil ports 68; the upper and lower chambers between the piston 62 and the piston chamber 63 are respectively connected to a set of oil ports 68; the set of oil ports 68 is connected to the hydraulic power station.
[0023] In a preferred embodiment, the main frame 1 includes a frame body 11 and a base plate 19. The upper surface of the frame body 11 is symmetrically provided with actuator mounting grooves 17, and a central guide post connecting through hole 16 is provided at the center of the upper surface. The lower surface of the frame body 11 is fixedly connected to the base plate 19. A lubrication cylinder mounting cavity 15 is provided below the central guide post connecting through hole 16. Reinforcing ribs 12 are provided at the connection between the frame body 11 and the base plate 19. The front of the frame body 11 has multiple first pipeline connecting through holes 13, and the two sides of the front of the frame body 11 have two second pipeline connecting through holes 14. Triangular plates 18 are welded to adjacent connecting walls inside the frame body 11. The main frame 1 can be formed by welding or casting. Casting saves more material, provides more installation space, and reduces weight and production costs.
[0024] In a preferred embodiment, a guide post assembly 7 is installed in the lubrication cylinder mounting cavity 15; the guide post assembly 7 includes an intermediate guide post 71, a flange 72, and a lubrication cylinder 73; the lubrication cylinder 73 is fixed in the lubrication cylinder mounting cavity 15 through the flange 72; the intermediate guide post 71 passes through the lubrication cylinder 73 and is fixedly connected to the bottom of the jaw bracket 4; the intermediate guide post 71 is used to absorb the lateral impact load during skin impact and improve the tensile quality.
[0025] In a preferred embodiment, the bracket 34 passes through the actuator mounting groove 17 and is fixedly installed in the opening groove; the pitch cylinder 32 is disposed inside the frame body 11; the tension cylinder 2 passes through the actuator mounting groove 17 and is hinged to the bottom of the jaw bracket 4.
[0026] In a preferred embodiment, a displacement sensor is provided in the stretching cylinder 2; the hydraulic power station controls the flow rate and hydraulic oil direction of the stretching cylinder 2 through a servo motor pump group and a proportional valve, so that the position of the stretching cylinder 2 can be precisely controlled, thereby realizing the control of the position and lifting speed of the jaw bracket 4, and thus positioning can be performed according to the position required for skin stretching.
[0027] In a preferred embodiment, the lower surface of the lower pad 65 and the upper surface of the upper pad 67 are provided with corresponding reverse teeth that are opposite to the stretching direction of the skin. The reverse teeth have 5 teeth per inch to increase the clamping friction on the skin. The lower pad 65 and the upper pad 67 are replaceable.
[0028] The follower mechanism 3 connects the integral jaw assembly 6 and the jaw bracket 4. The pitch cylinder 32 in the follower mechanism 3 is controlled by a solenoid valve. First, it is pre-stretched; at this point, the pitch cylinder 32 is fully retracted, and the solenoid valve is closed. At this time, the jaw assembly 6 and the jaw bracket 4 form a rigid body. When the skin is struck, requiring the jaw assembly 6 to follow, the solenoid valve controlling the pitch cylinder 32 opens, connecting the two chambers of the pitch cylinder 32. Based on the force and direction of the skin's action on the jaw assembly, the follower mechanism 3 lifts the jaw assembly 6 via the follower plate 5, and the jaw assembly 6 follows the follower plate 5. The maximum elevation angle can reach 42 degrees. The hydraulic power station controls the stretching cylinder 2 through a servo motor pump unit and a proportional valve. The servo motor pump unit includes a servo motor and an internal gear pump. A high-frequency proportional servo valve is configured in the stretching cylinder 2, and each stretching cylinder 2 is equipped with an external wire-type displacement sensor. A dual-axis tilt sensor is installed on the follower plate 5. The stretching force of the stretching cylinder 2 can be set by the proportional valve. Thus, under the drive of the hydraulic power station and the servo motor pump unit, flexible stretching of the skin can be achieved, ensuring stretching accuracy and thus improving the quality of skin stretching and greatly increasing the pass rate. The motor speed of the servo motor pump unit is adjustable. When configured with a fixed displacement pump, it can achieve high and low flow output. The system has a high degree of flexibility. The internal gear pump has high volumetric efficiency, low noise, and low pressure pulsation. This servo motor pump unit can achieve constant pressure output by utilizing the constant pressure control algorithm built into the motor driver. Compared with the commonly used combination of asynchronous motor + constant pressure variable pump, the system has more obvious advantages in maintainability and cost.
[0029] Although the specific embodiments of the present invention have been described and explained in detail above, it should be noted that various equivalent changes and modifications can be made to the above embodiments based on the concept of the present invention, and the resulting functions and effects do not exceed the spirit covered by the specification, and all such changes and modifications should be within the protection scope of the present invention.
Claims
1. A hydraulic control device for skin stretching, comprising a main frame, a stretching cylinder, a follow-up mechanism, a jaw bracket, a jaw assembly, and a hydraulic power station; characterized in that, The jaw bracket is equipped with a jaw follower plate; the jaw follower plate is equipped with a jaw assembly; a set of tension cylinders is located below the jaw bracket; the bottom of the set of tension cylinders is fixed to the base plate inside the main frame; the follower mechanism is fixed to the jaw bracket, and the pitch cylinder in the follower mechanism is movably connected to the follower plate, and the set of follower mechanisms lifts the follower plate through the pitch cylinder; the follower plate is connected to the jaw bracket through a rotating connecting shaft; the tension cylinder and the pitch cylinder are connected to the hydraulic power station.
2. The skin stretching hydraulic control device according to claim 1, characterized in that, The follower mechanism includes a pitch connecting block, a pitch cylinder, a bracket, a bracket docking plate, a pitch cylinder fixing plate, and a pitch cylinder connecting frame; a set of brackets are connected and fixed through the bracket docking plate; a pitch cylinder fixing plate is provided on the bracket docking plate; a pitch cylinder connecting frame is installed on the pitch cylinder fixing plate; the piston rod end of the pitch cylinder is movably connected to the pitch connecting block, and the cylinder bottom of the pitch cylinder is movably connected to the pitch cylinder connecting frame.
3. The skin stretching hydraulic control device according to claim 2, characterized in that, A bracket mounting plate is fixed to the top of the bracket; an opening groove is provided on the bottom plane of the jaw bracket; the bracket mounting plate is fixedly installed in the opening groove; a dual-axis tilt sensor is provided on the lower surface of the follower plate.
4. The skin stretching hydraulic control device according to claim 1, characterized in that, The jaw assembly consists of multiple jaw units, each jaw unit including an upper cover plate, a piston, a guide block, a lower pad block, a jaw cylinder body, and an upper pad block. The jaw cylinder body has a piston chamber; a piston is housed within the piston chamber, and an upper cover plate is positioned above the piston chamber. The upper pad block is located below the piston; the lower pad block is positioned directly below the upper pad block. A guide block is located on the side of the jaw cylinder body. A pressure sensor is also installed in the piston chamber. The hydraulic power station controls the piston's position and speed via a servo motor pump unit and an electromagnetic switch valve.
5. The skin stretching hydraulic control device according to claim 4, characterized in that, The upper surface of the upper pad is provided with a displacement detector facing the piston; the cylinder body of the jaw cylinder is provided with a set of oil ports; the upper and lower chambers between the piston and the piston chamber are respectively connected to a set of oil ports; the set of oil ports is connected to the hydraulic power station.
6. The skin stretching hydraulic control device according to claim 2, characterized in that, The main frame includes a frame body and a base plate; the upper surface of the frame body is symmetrically provided with actuator mounting grooves, and the center of the upper surface is provided with a central guide post connecting through hole; the lower surface of the frame body is fixedly connected to the base plate; a lubrication cylinder mounting cavity is provided below the central guide post connecting through hole; the part where the frame body connects to the base plate is provided with reinforcing ribs; the front of the frame body is provided with multiple first pipeline connecting through holes, and the two sides of the front of the frame body are provided with two second pipeline connecting through holes; triangular plates are welded to the adjacent connecting walls inside the frame body.
7. The skin stretching hydraulic control device according to claim 6, characterized in that, A guide post assembly is installed in the lubrication cylinder mounting cavity; the guide post assembly includes an intermediate guide post, a flange, and a lubrication cylinder; the lubrication cylinder is fixed in the lubrication cylinder mounting cavity by the flange; the intermediate guide post passes through the lubrication cylinder and is fixedly connected to the bottom of the jaw bracket.
8. The skin stretching hydraulic control device according to claim 6, characterized in that, The bracket is fixedly installed in the opening slot after passing through the actuator mounting slot; the pitch cylinder is set inside the frame body; the tension cylinder is hinged to the bottom of the jaw bracket after passing through the actuator mounting slot.
9. The skin stretching hydraulic control device according to claim 1, characterized in that, The stretching cylinder is equipped with a displacement sensor; the hydraulic power station controls the flow rate of the stretching cylinder and the direction of hydraulic oil flow through a servo motor pump set and a proportional valve.
10. A skin stretching hydraulic control device according to claim 4, characterized in that, The lower surface of the lower pad and the upper surface of the upper pad are provided with corresponding reverse teeth that are opposite to the stretching direction of the skin.