Controllable pre-tightening force tool and application

Abstract

Controllable pre-tightening force tooling, including base module, adjustable support compression mechanism module and preset pre-tightening force auxiliary support compression mechanism module; base module includes base (21), hexagonal screw C and limit block (13); on the circular base, three groups of threaded holes for fixing the adjustable support compression mechanism are distributed; there are three to five T-shaped grooves; the adjustable support compression module includes a fixed base, a top ball B (25), a threaded top rod, a hexagonal screw E, a support screw, the fixed base is fixed on the base (21) through the hexagonal screw F, the convex spherical surface of the top ball B is inserted into the concave spherical surface of the threaded top rod (26), and the threaded top rod moves up and down in the matched threaded pin hole in the fixed base (23); the preset pre-tightening force auxiliary support compression mechanism; a hydraulic jacking column (3) is installed on the movable base, a top ball A is above the hydraulic jacking column, and the hydraulic jacking column can move up and down.

Description

Technical Field

[0001] This invention relates to a tooling with controllable pre-tightening force, which is used to process thin-walled components such as cavity stabilizers. Background Technology

[0002] With the continuous development of modern aviation technology, various aircraft are placing increasingly higher demands on engine performance in areas such as start-up, climb, and emergency response. To address this issue, the concept of afterburner was proposed. An afterburner utilizes the residual oxygen in the exhaust gas from the main combustion chamber, injecting fuel into it for further combustion. This rapidly increases the gas temperature, thereby increasing engine thrust. Because the afterburner is located after the turbine, the incoming gas velocity within it is exceptionally high, far exceeding the flame propagation speed. Furthermore, since the gas flow in the afterburner originates from the main combustion chamber, its oxygen content is significantly lower, posing a considerable challenge to stable combustion within the afterburner. To achieve flame stability, a cavity stabilizer is introduced into the afterburner.

[0003] Due to the design requirements of modern aero engines, all bosses, shapes, holes, internal cavities, oblique holes, and slots in the upper part need to be machined to meet the technical requirements of the design drawings. However, these components include both circumferential and oblique surfaces, forcing us to use five-axis machining to ensure the workpiece is machined completely according to the design requirements. This significantly increases costs. Furthermore, the spindle head structure of five-axis machine tools (generally requiring a gantry-type five-axis machining center) results in long tool overhangs, making them prone to sudden issues such as tool vibration during machining, leading to tool damage and low efficiency. To address these issues, and considering currently available equipment, we have developed the following process solution: using an 805 three-axis vertical machining center, equipped with a rotary table and angle head, and designing a tooling system with controllable pre-clamping force, we will use this method to machine thin-walled components such as cavity stabilizers (which have complex internal structures).

[0004] When machining thin-walled components such as cavity stabilizers, the general requirement is that the workpiece be clamped by a fixture with a controllable pre-clamping force (appropriate pre-clamping force). Excessive clamping force will deform the thin-walled workpiece, or too loose a clamping force will cause the workpiece to fail to be clamped, potentially leading to workpiece displacement during machining. Cavity stabilizers have a complex structure, featuring a disc-shaped thin-walled cavity. Cavity flame stabilizers are key components in the combustion chamber of scramjet engines used to enhance fuel mixing and maintain flame stability. Their core feature is the flame stabilization effect achieved through the recirculation zone formed within the cavity. For example... Figure 1 As shown, the parts can only be produced as blanks using 3D printing, and the precision is far from sufficient for direct use in engines. Summary of the Invention

[0005] The purpose of this invention is to propose a tooling with controllable pre-tightening force and its application. With the help of this tooling, a three-axis vertical machining center, a turntable, and an angle head can be used to process thin-walled components such as cavity stabilizers, thereby reducing costs and ensuring stable product quality.

[0006] The technical solution of the present invention is a tooling with controllable pre-tightening force, comprising three parts: a base module, an adjustable support and clamping mechanism module, and a preset clamping force auxiliary support and clamping mechanism module;

[0007] The base module consists of three parts: a base 21, an internal hexagon screw C, and a limiting block 13. On the circular base, there are three sets of threaded holes for fixing the adjustable support and clamping mechanism. There are also three to five T-slots for installing the preset clamping force auxiliary support and clamping mechanism. Each T-slot is provided with a limiting block 13 fixed by an internal hexagon screw C. This constitutes the base module.

[0008] The adjustable support clamping module includes a fixed base, a top ball B25, a threaded top rod, an internal hexagon screw E (rod), and a support screw. The fixed base 23 is fixed to the base by the internal hexagon screw F24. Three sets of threaded holes 23-1 for fixing the adjustable support clamping mechanism are provided. The convex spherical surface of the top ball B is inserted into the concave spherical surface of the threaded top rod 26. The external thread of the threaded top rod engages with the threaded pin hole provided on the fixed base 23. The threaded top rod moves up and down in the mating threaded pin hole in the fixed base 23, so that the flat part of the top ball B25 can always maintain contact with one surface or at least three points when it contacts the flat surface of the workpiece or a not very flat surface. Then, the support screw (rod) 19 is screwed into the threaded hole of the pressure plate 20 and adjusted to a suitable length. One end of the pressure plate is screwed onto the support screw, and the pressure plate is pressed on the workpiece in a suitable position. The upper end of the internal hexagon screw E18 passes through the hole on the pressure plate, and the lower end of the internal hexagon screw E18 is screwed into the threaded hole on the fixed base to fix the center of the pressure plate and clamp the workpiece.

[0009] A preset clamping force auxiliary support clamping mechanism includes a top ball A, a hydraulic top column 3, a sealing ring B16, a hexagonal socket head cap screw, a movable base 8, a T-block, a hexagonal tightening screw A, a steel ball 4 and a spring 5, a hexagonal tightening screw B11, and a sealing pressure relief seat 10; the fixed hexagonal socket head cap screw D is inserted into the corresponding screw hole of the movable base from above, and a T-block 14 is installed below the hexagonal socket head cap screw D; the T-block is installed in the T-slot on the base module;

[0010] The hydraulic jack 3 is installed on the movable base 8. The top ball A is above the hydraulic jack 3. The hydraulic jack 3 can move up and down, so that the flat part of the top ball A can always maintain contact with one surface or at least three points when it contacts the flat surface of the workpiece or a not very flat surface. Then, the support screw (rod 19) is screwed into the threaded hole of the pressure plate 20 and adjusted to a suitable length. One end of the pressure plate 20 is screwed onto the support screw. The pressure plate is pressed on the workpiece in a suitable position. The upper end of the hexagonal socket screw E18 passes through the hole on the pressure plate and the lower end of the hexagonal socket screw E18 is screwed into the threaded hole on the fixed base to fix the center of the pressure plate and press the workpiece.

[0011] Insert the steel ball 4 and spring 5 into the inner hole of the sealing pressure relief seat 10 in sequence, screw the hexagon socket head cap screw B11 into the sealing pressure relief seat 10 to form a new component, insert this new component into the inner hole of the hydraulic jack 3, and use the hexagon socket head cap screw B9 to fix the new component on the movable base 8.

[0012] The movable base 8 has a threaded hole at its rear end, which allows a suitable amount of hydraulic oil to be injected into the inner cavity of the movable base 8. The cylindrical end of the internal hexagonal head screw 17 with the sealing ring B16 installed is inserted into the corresponding hole at the rear end of the movable base 8, and the thread of the internal hexagonal head screw 17 is screwed into the movable base 8.

[0013] This forms the main body of the preset clamping force auxiliary support and pressing mechanism. By placing a weight of appropriate weight (simulating the preset clamping force) on the upper surface of the top ball A1, and then continuously screwing in the internal hexagonal head screw 17, the hydraulic oil fills the inner cavity of the movable base 8 and forms a certain pressure value. By adjusting the depth of the internal hexagonal head screw B11 screwed into the sealing pressure relief seat 10, the elastic force of the spring 5 is changed, so that the steel ball 4 disengages from the conical surface on the inner hole 10 of the sealing pressure relief seat when the force is appropriate, thereby relieving the excessive pressure in the movable base 8 and obtaining the preset clamping force we need.

[0014] Furthermore, the convex spherical surface of the top ball A1 is inserted into the concave spherical surface of the hydraulic top column 3, the assembly is inserted into the movable base 8 with the sealing ring A6 installed, and the orientation is adjusted so that the cylindrical surfaces of the two internal hexagonal head screws A2 are respectively vertically inserted into the two long grooves on the side of the hydraulic top column 3.

[0015] Finally, screw the support screw 19 into the threaded hole 23-1 of the pressure plate 20, adjust it to a suitable length, press the pressure plate onto the workpiece in the appropriate position, and tighten the workpiece with the internal hex screw E18.

[0016] This results in a component that can be preset with a clamping force to assist in supporting and pressing the mechanism.

[0017] The tooling with controllable pre-tightening force of the present invention is applied to the processing of thin-walled cylindrical or disc-shaped components such as cavity stabilizers.

[0018] Beneficial Effects: The tooling fixture of this invention utilizes the principle of three points defining a surface, making workpiece adjustment very convenient and quick. Simultaneously, by pre-setting the pre-clamping force to assist in supporting the workpiece, it effectively controls workpiece deformation during clamping, laying a solid foundation for stable quality. Using tooling with controllable pre-clamping force to process thin-walled cylindrical (frustum, etc.) or disc-shaped components such as cavity stabilizers, the design, use, and process of this invention significantly reduce the processing cost of these products, offering high efficiency, controllable costs, and stable product quality. It can meet the requirements of completing turning, inspection, and milling processes for parts in a single clamping operation. Of course, thin-walled components such as cavity stabilizers are generally cylindrical, disc-shaped, or conical parts; using the clamping of this invention, vertical turning, milling, boring, and other machining operations can be performed, greatly improving machining accuracy. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the workpiece structure processed according to the present invention;

[0020] Figure 2 This is a partial cross-sectional structural schematic diagram of the tooling of the present invention;

[0021] Figure 3 This is a schematic diagram of the base module structure of the tooling of the present invention;

[0022] Figure 4 A schematic diagram of the adjustable support and clamping mechanism of the tooling of the present invention;

[0023] Figure 5 yes Figure 4 A sectional view;

[0024] Figure 6A Schematic diagram of the front structure of the movable base;

[0025] Figure 6B Schematic diagram of the rear structure of the movable base;

[0026] Figure 7 Sealing pressure relief seat 10

[0027] Figure 8 Schematic diagram of hydraulic jack 3 structure;

[0028] Figure 9 Schematic diagram of fixed base 23;

[0029] Figure 10 Schematic diagram of threaded push rod 26.

[0030] Figure 11 This is a schematic diagram of the top ball structure of the present invention. Detailed Implementation

[0031] The parts marked in the diagram are: 1. Top ball, 2. Socket head cap screw, 3. Hydraulic jack, 4. Steel ball, 5. Spring, 6. Sealing ring, 7. Socket head cap screw, 8. Movable base, 9. Socket head cap screw, 10. Sealing pressure relief seat, 11. Socket head cap screw, 12. Limit block, 13. T-block, 14. T-slot, 14-1, 15. Socket head cap screw, 16. Sealing ring, 17. Socket head cap screw, 18. Support screw, 19. Pressure plate, 20. Base, 21. Workpiece, 22. Fixed base, 23. Hydraulic jack mounting position 3-1, Top ball mounting position 3-2, Socket head cap screw... Screw E18 mounting position 18-1, socket head cap screw A2 mounting position 2-1; socket head cap pressurizing screw mounting position 17-1, limiting surface 3-3, hydraulic oil inlet 3-4, sealing ring mounting groove 3-5, socket head cap screw D15 mounting position 15-1; in the sealing pressure relief seat 10: oil passage groove 10-1, spring mounting position 5-1, socket head cap screw B mounting position 9-1, socket head cap screw B mounting position 11-1; fixed base 23, threaded push rod mounting position 26-1, socket head cap screw F mounting position 24-1, socket head cap screw E mounting position 18-1; threaded push rod 26. Schematic diagram of hydraulic push column 3;

[0032] This tooling utilizes a three-axis vertical machining center with a rotary table and angle head, and uses a tooling with controllable pre-clamping force to process thin-walled components such as cavity stabilizers. The design, use, and process of the tooling of this invention can significantly reduce the processing cost of this type of product, and has high efficiency, controllable cost, and stable product quality.

[0033] 1. Process flow using the tooling of this invention

[0034] Since the blank of the cavity stabilizer is a 3D printed part, its consistency is not very good. Moreover, due to the design requirements, its wall thickness is only 2 to 3 millimeters, and the structural rigidity is not very good. It is easy to deform when affected by external forces.

[0035] To address the above issues, we designed a process flow for machining the cavity stabilizer on a three-axis vertical machining center, using a rotary table and angle head: Draw the upper and lower angular reference lines, check the allowance of each machining surface --- clamp the workpiece on a special fixture as required --- turn the upper plane and outer cylindrical reference surface of the part --- use blue light scanning to determine the allowance of each surface of the workpiece --- rough turn the outer shape and inner cavity of the part --- aging treatment --- finish turn each surface of the part --- rough and finish mill the inner and outer bosses of the part on the rotary table --- repair and clean the workpiece --- mark --- final inspection of the part.

[0036] In the process of this invention, since the part is a 3D printed workpiece, we first draw the upper and lower reference lines and angular reference lines of the part according to the reference surface of the blank drawing, and roughly check whether there is any allowance on each machining surface. After confirming the allowance, the workpiece is placed on a special tooling (i.e., the tooling of this invention). Based on the previous drawing, the workpiece is clamped and then put on a lathe to rough machine the outer circle and plane reference. Then, blue light scanning is used to finally confirm that there is no problem with the workpiece clamping (if the scan finds that there is no allowance in some places, the workpiece needs to be re-clamped, the outer circle and plane are rough machined again, and blue light scanning is checked again until it is qualified). After blue light inspection, the outer shape and inner cavity of the part are rough machined, and then natural aging is performed. After aging, each surface is precision machined. After the machining is completed, the workpiece and the tooling are mounted on the turntable of the vertical machining center. An angle head is used to machine the surfaces, holes, grooves, etc. that need to be machined. Finally, the workpiece is clamped, cleaned and marked, and the part is finally inspected.

[0037] By adopting this process flow, the turnover speed of workpieces is effectively improved by shortening the process route length, thus increasing efficiency. The use of roughing, semi-finishing to finishing and natural aging methods effectively controls the deformation of parts. At the same time, the use of secondary blank allowance inspection ensures the first-pass yield of parts and stabilizes product quality.

[0038] 2. Specific structure of tooling

[0039] Design according to the requirements of part processing, such as Figure 2 As shown, this fixture can meet the requirements of completing machining and inspection processes such as turning, inspection, and milling of a part in a single clamping operation. Based on the principle of three points defining a surface, this fixture is very convenient and quick to adjust the workpiece. Simultaneously, by pre-setting the clamping force to assist in supporting the workpiece, it effectively controls workpiece deformation during clamping, laying a solid foundation for stable quality.

[0040] This fixture mainly consists of three parts: a base module, an adjustable support and clamping mechanism module, and a preset clamping force auxiliary support and clamping mechanism module.

[0041] (1) Base module

[0042] Figure 3 As shown, the base module consists of three parts: a base 21, hexagon socket screws C12, and a limiting block 13. On the circular base 21, there are three sets of four screw holes for fixing the adjustable support and clamping mechanism; there are also five T-slots for installing the preset clamping force auxiliary support and clamping mechanism. Each T-slot has a limiting block 13 fixed by two C12 hexagon socket screws. This forms the base module.

[0043] Adjustable support clamping mechanism, such as Figure 4As shown, the adjustable support clamping mechanism uses four hexagon socket screws F24 to fix the fixed base 23 to the base 21. The convex surface of the top ball B25 is inserted into the concave surface of the threaded top rod 26. By pinching and rotating the knurled surface of the threaded top rod 26, the threaded top rod 26 engages with the thread of the fixed base 23, causing it to move up and down within the mating pin hole in the fixed base 23. This ensures that the flat portion of the top ball B25 maintains contact at one surface or at least three points when contacting a flat or uneven surface, thus guaranteeing the stability of the contact surface. Next, the support screw 19 is screwed into the threaded hole of the pressure plate 20 and adjusted to a suitable length. The pressure plate 20 is then pressed onto the workpiece at a suitable position, and the workpiece is clamped using hexagon socket screws E18. This forms the adjustable support clamping mechanism component module.

[0044] The pre-set clamping force can assist in supporting the clamping mechanism.

[0045] Insert the convex spherical surface of the top ball A1 into the concave spherical surface of the hydraulic jack 3. Insert the assembly into the movable base 8 with the sealing ring A6 installed, and adjust its orientation so that the cylindrical surfaces of the two socket head cap screws A2 respectively engage in the two long grooves on the side of the hydraulic jack 3. Insert the steel balls 4 and 5 springs into the inner hole of the sealing pressure relief seat 10 in sequence. Screw the socket head cap screw B11 into the sealing pressure relief seat 10 to form a new assembly. Insert this new assembly into the inner hole of the hydraulic jack 3, and use the socket head cap screw B9 to fix the new assembly to the movable base 8.

[0046] A suitable amount of hydraulic oil is injected into the inner cavity of the movable base 8 through the threaded hole at the rear end of the movable base 8. The cylindrical end of the 17 socket head cap screw with the 16 sealing ring B installed is inserted into the corresponding hole at the rear end of the movable base 8, and the thread of the 17 socket head cap screw is screwed into the movable base 8. At this time, the main body of the preset clamping force auxiliary support clamping mechanism is formed. By placing an appropriate weight on the upper surface of the 1 top ball A (simulating the preset clamping force), and then continuously screwing in the 17 socket head cap screw, the hydraulic oil fills the inner cavity of the movable base 8 and forms a certain pressure value. By adjusting the depth of the 11 socket head cap screw B screwed into the 10 sealing pressure relief seat, the elastic force of the 5 spring is changed, so that the 4 steel ball disengages from the contact with the inner conical surface of the 10 sealing pressure relief seat when the force is appropriate, thereby relieving the excessive pressure in the movable base 8 and obtaining the required preset clamping force.

[0047] Then use two 15mm hexagon socket screws D to insert into the screw holes corresponding to the 8mm movable base from above, and install the 14mm T-block below the two screws.

[0048] Finally, screw the 19 support screws into the threaded hole of the 20 pressure plate, adjust to the appropriate length, press the 20 pressure plate onto the workpiece in the appropriate position, and tighten the workpiece with the 18 socket head cap screws E. This forms an assembly with a preset clamping force to assist in supporting and pressing the mechanism.

[0049] Assembly and use of the tooling: To assemble the tooling, place the base module face up on the platform. Connect the three adjustable support clamping mechanism components to the three sets of four threaded holes on the base module using hexagonal screws F24. Adjust the position so that the circle formed by the centers of the three top balls B25 is as concentric as possible with the base module.

[0050] Five preset pressure, preset clamping force (three or four evenly distributed are also acceptable; considering the thin-walled structure, more preset clamping force devices are better) auxiliary support clamping mechanism components are installed into the T-slot of the base module via T-block 14, so that the top ball A1 is away from the center of the base module. Note that the movable base 8 should not be pushed all the way down, so that the limiting block 13 on the base module has a certain distance from the limiting surface below the movable base 8 to facilitate workpiece clamping. This completes the tooling assembly.

[0051] To use the tooling, place the assembled tooling on the platform, remove one adjustable support clamping mechanism component module, and place the workpiece on the tooling in an eccentric manner. At this time, the remaining two adjustable support clamping mechanism component modules are just stuck in the grooves of the workpiece's inner cavity. Then, adjust the threaded push rod 26 of the removed adjustable support clamping mechanism component module to the lowest position, and then reinstall the adjustable support clamping mechanism component module back to its original position. Adjust the position of the workpiece so that the workpiece is basically concentric with the tooling.

[0052] Based on the allowance lines marked in the previous process, the allowance lines are aligned to the horizontal plane by adjusting the height of the height gauge and the threaded push rod 26. The pressure plate 20 on the three adjustable support clamping mechanism assembly module is placed in the appropriate position on the workpiece, so that the upper surface of the push ball B 25 on the three adjustable support clamping mechanism assembly module is in stable contact with the workpiece at least 3 points. The workpiece is then clamped by the hex socket screw E18. At this point, the main body of the workpiece is clamped. Next, the assembly of the pre-set clamping force auxiliary support clamping mechanism assembly is started.

[0053] Retract the hexagonal head screw 17 on the component of the preset-tightening-force auxiliary support and clamping mechanism all the way to the bottom, so that the plane of the top ball A1 on the hydraulic top column 3 is lowered to the lowest surface. Retract the movable base 8 all the way to the bottom, so that the limiting block 13 on the base module contacts the limiting surface below the movable base 8. Tighten the two hexagonal head screws D15 on the component of the preset-tightening-force auxiliary support and clamping mechanism to fix the component of the preset-tightening-force auxiliary support and clamping mechanism on the base module. Turn the hexagonal head screw 17 inward. Tighten the hydraulic jack 3 and push it upward. When the flat surface of the ball A1 on the hydraulic jack 3 contacts the workpiece, continue to tighten the internal hexagonal head screw 17 until the preset pressure is reached. At this time, lock the two internal hexagonal head screws A2. Place the pressure plate 20 on the five preset tightening force auxiliary support clamping mechanism components in the appropriate position of the workpiece, and press the workpiece with the internal hexagonal head screw E18. Check whether each contact surface is in contact and whether each screw is tightened. After confirming that there are no errors, the workpiece clamping is completed.

[0054] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., 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 tooling with controllable pre-tightening force, characterized in that, It consists of three parts: a base module, an adjustable support and clamping mechanism module, and a preset clamping force auxiliary support and clamping mechanism module. The base module consists of three parts: a base (21), an internal hexagon screw C, and a limiting block (13); on the circular base, there are three sets of threaded holes for fixing the adjustable support and clamping mechanism; there are also three to five T-slots for installing the preset clamping force auxiliary support and clamping mechanism; each T-slot is provided with a limiting block fixed by an internal hexagon screw C; thus forming the base module; The adjustable support clamping module includes a fixed base, a top ball B (25), a threaded top rod, an internal hexagonal screw E, and a support screw. The fixed base is fixed on the base (21) by the internal hexagonal screw F (24). Three sets of threaded holes are used to fix the adjustable support clamping mechanism. The convex spherical surface of the top ball B is inserted into the concave spherical surface of the threaded top rod (26). The external thread of the threaded top rod meshes with the threaded pin hole provided on the fixed base. The threaded top rod moves up and down in the mating threaded pin hole in the fixed base (23), so that the flat part of the top ball B can always maintain contact with one surface or at least three points when it contacts the workpiece plane or a not very flat surface. Then, the support screw (19) is screwed into the threaded hole of the pressure plate (20) and adjusted to a suitable length. One end of the pressure plate (20) is screwed onto the support screw. The pressure plate is pressed on the workpiece in a suitable position. The upper end of the internal hexagonal screw E passes through the hole on the pressure plate and the lower end of the internal hexagonal screw E (18) is screwed into the threaded hole on the fixed base to fix the center of the pressure plate to clamp the workpiece. The pre-set top-tightening force auxiliary support clamping mechanism includes a top ball A, a hydraulic top column (3), a sealing ring B (16), an internal hexagonal pressurizing screw, a movable base (8), a T-block, a hexagonal tightening screw A, a steel ball (4), a spring (5), an internal hexagonal tightening screw B (11), and a sealing pressure relief seat (10); The internal hexagonal screw D for fixing is inserted into the corresponding screw hole of the movable base from above, and a T-block (14) is installed below the internal hexagonal screw D; the T-block is installed in the T-slot on the base module; The hydraulic jack (3) is installed on the movable base. The top ball A is above the hydraulic jack. The hydraulic jack can move up and down, so that the flat part of the top ball A can always maintain contact with one surface or at least three points when it contacts the workpiece surface or a not very flat surface. Then, the support screw (19) is screwed into the threaded hole of the pressure plate and adjusted to a suitable length. One end of the pressure plate is screwed onto the support screw. The pressure plate is pressed on the workpiece in a suitable position. The upper end of the internal hex screw E (18) passes through the hole on the pressure plate and the lower end of the internal hex screw E is screwed into the screw hole on the fixed base to fix the center of the pressure plate to press the workpiece. Insert the steel ball and spring into the inner hole of the sealing pressure relief seat in sequence, screw the internal hexagonal head screw B (11) into the sealing pressure relief seat to form a new component, insert this new component into the inner hole of the hydraulic top column, and use the internal hexagonal head screw B (9) to fix the new component on the movable base; The rear end of the movable base is provided with a threaded hole. A suitable amount of hydraulic oil is injected into the inner cavity of the movable base 8. The cylindrical end of the internal hexagonal pressure screw (17) with the sealing ring B (16) installed is inserted into the corresponding hole at the rear end of the movable base (8), and the thread of the internal hexagonal pressure screw (17) is screwed into the movable base.

2. The tooling with controllable pre-tightening force according to claim 1, characterized in that, Insert the convex spherical surface of the top ball A into the concave spherical surface of the hydraulic jack, insert the assembly into the movable base with the sealing ring A installed, and adjust the direction so that the cylindrical surfaces of the two internal hexagonal head screws A are respectively vertically inserted into the two long grooves on the side of the hydraulic jack.

3. The tooling with controllable pre-tightening force according to claim 1, characterized in that, The steel ball contacts the upper conical surface of the inner hole of the sealing pressure relief seat, so that the steel ball (4) is separated from the upper conical surface of the inner hole of the sealing pressure relief seat (10) when the appropriate force is applied, thereby relieving the excessive pressure in the movable base (8).

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