Device for tightening fine-thread flexible workpiece

Abstract

The utility model relates to a device for tightening a fine thread flexible workpiece, which comprises a shape correction guide mechanism, a horizontal floating mechanism, a supporting mechanism and a screwing-in mechanism, and is characterized in that the shape correction guide mechanism is used for shape correction of the outer surface of the cross section of the fine thread flexible workpiece to be tightened; the horizontal floating mechanism is used for installing an internal thread workpiece to be tightened; the supporting mechanism is fixed to one side of the shape correcting guide mechanism and provided with a lifting air cylinder, an upper limiting sensor and a lower limiting sensor. The screwing-in mechanism is arranged on the supporting mechanism, is driven by a lifting air cylinder to move up and down and comprises a motor, a planetary reducer, a torsion sensor and a universal floating joint mechanism, the universal floating joint mechanism is connected with the universal floating joint mechanism through a transmission shaft and a bearing which are coaxially connected, and an external thread workpiece is hoisted below the universal floating joint mechanism. The tightening device for the fine-thread flexible workpiece is suitable for tightening thin-wall soft metal fine threads, and thread tips are prevented from being damaged, the outer walls of the threads are prevented from deforming and protruding, and chippings are prevented from being generated.

Description

Technical Field

[0001] This utility model relates to the field of mechanical technology, specifically to a device for tightening thin-walled, fine-threaded flexible workpieces, and particularly to a device and method for tightening thin-walled, fine-threaded flexible workpieces made of low-hardness metal materials after assembly inside the outer shell of a warhead and tightening them with the wind cap. Background Technology

[0002] The warhead of a man-portable weapon typically consists of a wind cap (externally threaded part), a projectile body (internally threaded part), and a propellant charge. The wind cap and the projectile body are connected by fine-threaded treads. Both parts are made of soft metal material 2A12 aluminum. Both parts are thin-walled with fine threads, and the opening of the thin-walled cylindrical section of the projectile body is prone to ellipticing, which makes the threaded connection of the two parts difficult to assemble.

[0003] Currently, existing tightening devices generally consist of a tightening gun or tightening motor, a product fixing component, and the screw or workpiece to be tightened. They are typically designed for automatically tightening coarse-threaded or standard-threaded parts made of materials with high hardness. However, existing tightening devices encounter the following problems when tightening fine-threaded parts made of thin-walled soft metal materials: 1) When tightening fine-threaded parts made of large-diameter thin-walled soft metal materials, the internal thread cannot be properly aligned due to deformation after machining due to the thin wall; 2) After alignment, the soft material easily generates debris, which can clog the thread tips and damage them; 3) After tightening, debris in the grooves can press against the thread tips, causing deformation and bulging of the outer wall of the thread, resulting in surface defects. Due to these problems, existing tools and equipment cannot automatically tighten fine-threaded parts made of thin-walled soft metal materials. Current equipment cannot achieve automatic thread alignment of these two parts; currently, skilled workers must manually align the two threads, which poses safety hazards due to the use of hot work.

[0004] In response to the nation's major decisions and deployments regarding safe production, and to meet safety work requirements, there is an urgent need to develop an automatic threading technology for thin-walled, fine-threaded steel to fundamentally eliminate potential safety hazards. Therefore, it is imperative to develop a tightening device suitable for thin-walled, soft metal materials with fine threads, thereby improving manufacturing precision and preventing product damage. Summary of the Invention

[0005] The technical problem this utility model aims to solve is that existing screw thread tightening methods fail to tighten fine threads on thin-walled soft materials, and existing tightening devices cannot meet the tightening requirements of fine threads on thin-walled soft metal materials, resulting in problems such as inability to tighten threads, damage to thread tips, deformation and protrusion of the thread outer wall, generation of debris after tightening, and deformation of the thread outer wall.

[0006] To solve the above-mentioned technical problems, this utility model provides a device for tightening flexible workpieces with fine threads. The flexible workpieces with fine threads include internal thread workpieces and external thread workpieces. The device for tightening the flexible workpieces with fine threads includes: a alignment guide mechanism, which has a base with a cavity in the middle and a pair of X-axis linear slide rails on the upper part. A front alignment slide plate and a rear alignment slide plate, which can move relative to each other, are arranged on the slide rails. Semi-circular grooves are formed on adjacent sides of the front and rear alignment slide plates, and the inner diameter of the circular hole formed by the two semi-circular grooves is larger than the outer diameter of the cross-section of the flexible workpiece with fine threads to be tightened; and a horizontal floating mechanism, disposed in the alignment guide mechanism, for mounting the internal thread workpiece to be tightened. The horizontal floating mechanism includes a base plate in contact with the base, and a fixed plate, a horizontal floating plate, and an internal thread workpiece clamping block arranged sequentially from bottom to top. The internal thread workpiece clamping block includes components corresponding to the front alignment slide plate. The system includes a front clamping block for the internal threaded workpiece and a rear clamping block for the internal threaded workpiece corresponding to the alignment slide plate. A Z-axis transverse linear guide rail is provided on the fixed plate to slidably connect to a transverse floating plate. An X-axis longitudinal linear guide rail is provided on the transverse floating plate to slidably connect the front clamping block and the rear clamping block for the internal threaded workpiece, respectively. A support mechanism is fixed to one side of the alignment guide mechanism and extends upward in the Y direction. A lifting cylinder, an upper limit sensor, and a lower limit sensor are provided on the support mechanism. A screwing mechanism is located on the support mechanism and is driven by the lifting cylinder to move up and down along the Y direction. This mechanism includes a motor, a planetary reducer, a torque sensor, and a universal floating joint mechanism arranged sequentially from top to bottom along the axial direction above the internal threaded workpiece. The universal floating joint mechanism is connected to the external threaded workpiece via a coaxially connected transmission shaft and bearings. The external threaded workpiece is suspended below the universal floating joint mechanism.

[0007] According to an embodiment of the present invention, the universal floating joint mechanism may include: a cylindrical external thread workpiece connector, an external thread workpiece connecting pin that passes through and connects the external thread workpiece and the lower end of the external thread workpiece connector, a universal transmission block, a first universal transmission pin, and two second universal transmission pins.

[0008] According to an embodiment of this utility model, the universal drive block can be ring-shaped. The first universal drive pin passes through and slides between the universal drive block and the lower end of the drive shaft in the Z direction. The two second universal drive pins pass through and slide between the external thread workpiece connector and the universal drive block on both sides of the drive shaft in the Y direction, thereby realizing universal drive when the external thread workpiece is at the same height.

[0009] According to an embodiment of this utility model, the front and rear alignment slides can be connected to the alignment guide cylinder via alignment guide cylinder connecting rods, and the front and rear alignment slides are pushed by the alignment guide cylinder to run in opposite directions along the X direction of the linear slide rail.

[0010] According to an embodiment of the present invention, the alignment guide mechanism may further include: alignment guide blocks, there are two alignment guide blocks, which are respectively disposed on the semi-circular grooves of the front alignment slide and the rear alignment slide. The alignment guide blocks have arcs concentric with the semi-circular grooves of the front alignment slide and the rear alignment slide, and the inner diameter of the upper end of the alignment guide block is larger than the inner diameter of the lower end, so as to facilitate the introduction of the external threaded workpiece.

[0011] According to an embodiment of this utility model, fixing holes can be provided on the fixing plate, the horizontal floating plate, and the internal thread workpiece clamping block. After the horizontal floating mechanism clamps the internal thread workpiece, the horizontal floating switch shaft connected to the horizontal floating switch cylinder passes through the fixing hole to fix the internal thread workpiece.

[0012] According to an embodiment of the present invention, the shaping guide mechanism may further include: two shaping guide limit blocks, which are disposed on both sides of the opening between the front shaping slide plate and the rear shaping slide plate to prevent the front shaping slide plate and the rear shaping slide plate from being excessively clamped and to avoid deformation of the flexible workpiece with fine threads tightened.

[0013] According to an embodiment of this utility model, the inner diameter of the hole between the transverse floating plate and the fixed plate for accommodating the internal thread workpiece can be greater than 1.2 times the outer diameter of the internal thread workpiece, so as to ensure that the internal thread workpiece does not interfere with the transverse floating plate and the fixed plate when it floats.

[0014] According to an embodiment of the present invention, the screwing mechanism may further include a sensing plate.

[0015] According to an embodiment of the present invention, when the screwing mechanism Y moves up and down, when the sensing plate triggers the upper limit sensor, the lifting cylinder stops controlling the screwing mechanism to continue moving up, and when the sensing plate triggers the lower limit sensor, the lifting cylinder stops controlling the screwing mechanism to continue moving down.

[0016] According to an embodiment of this utility model, the horizontal floating switch shaft can have multiple segments with unequal outer diameters along the axial direction. The larger outer diameter segment is the positioning segment, which matches the inner diameter of the fixing hole, and the smaller outer diameter segment is the gap segment. When the horizontal floating switch cylinder pushes the horizontal floating switch axially upward through the horizontal floating switch cylinder connector, the horizontal floating switch shaft and the fixing hole are tightly fitted, so that the positions of the front clamping block of the internal thread workpiece, the transverse floating plate and the fixing plate are relatively fixed. When the horizontal floating switch cylinder pulls the horizontal floating switch axially downward through the horizontal floating switch cylinder connector, the horizontal floating switch shaft and the fixing hole maintain a gap, so that the front clamping block of the internal thread workpiece can float freely in the longitudinal direction and the transverse floating plate can float freely in the transverse direction.

[0017] Compared with the prior art, the technical solution provided by the embodiments of this utility model can achieve at least the following beneficial effects:

[0018] According to the present invention, the device for tightening flexible workpieces with fine threads uses an external force to round the joint of the workpiece through a shaping and guiding mechanism, and at the same time guides the screw threads to address the problem that the internal and external threads cannot be screwed in due to the thin wall deformation of the workpiece.

[0019] This invention can calibrate the inlet of the screw-in workpiece with internal thread and keep the horizontal floating mechanism that fixes the internal thread workpiece in a horizontal free state. At the same time, the screwed-in external thread workpiece adopts a universal floating state, which reduces the error of parallelism between the screw threads processed on the workpiece and the workpiece clamping surface and the cumulative tolerance of the assembly of the tightened and clamped workpiece.

[0020] This invention uses a lifting cylinder and a screwing mechanism to control the screwing process, preventing excessive or insufficient screwing pressure from increasing friction during screwing. This avoids the problems of debris and deformation of the outer wall of the screw after screwing in external threaded workpieces, thereby improving processing accuracy, product yield, and production efficiency.

[0021] The device for tightening flexible workpieces with fine threads according to this utility model can tighten soft materials, such as 2A12 aluminum, thin-walled fine internal and external threads, without damaging the threads during the tightening process, and can set the tightening force and the number of turns. Attached Figure Description

[0022] To more clearly illustrate the technical solutions of the embodiments of this utility model, the accompanying drawings of the embodiments will be briefly introduced below. Obviously, the drawings described below only relate to some embodiments of this utility model, and are not intended to limit this utility model.

[0023] Figure 1 This is a schematic diagram illustrating a device for tightening a flexible workpiece with fine threads according to an embodiment of the present invention;

[0024] Figure 2 This is a schematic diagram showing a universal floating joint mechanism according to an embodiment of the present utility model;

[0025] Figure 3 This is an exploded view of the screwing mechanism according to an embodiment of the present invention;

[0026] Figure 4 This is a schematic diagram showing the screwing mechanism, the alignment guide mechanism, and the horizontal floating mechanism according to an embodiment of the present utility model;

[0027] Figure 5 This is a cross-sectional view showing a device for tightening a flexible workpiece with fine threads according to an embodiment of the present invention;

[0028] Figure 6 This is an exploded view of a horizontal floating mechanism according to an embodiment of the present invention. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. Based on the described embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0030] Unless otherwise defined, the technical or scientific terms used herein shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains. The terms “first,” “second,” and similar terms used in this patent application specification and claims do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, the terms “an” or “a” and similar terms do not indicate a limitation of quantity, but rather indicate the presence of at least one.

[0031] Figure 1 This is a schematic diagram illustrating a device for tightening a flexible workpiece with fine threads according to an embodiment of the present invention; Figure 2 This is a schematic diagram showing a universal floating joint mechanism according to an embodiment of the present utility model; Figure 3 This is an exploded view of the screwing mechanism according to an embodiment of the present invention; Figure 4 This is a schematic diagram showing the screwing mechanism, the alignment guide mechanism, and the horizontal floating mechanism according to an embodiment of the present utility model; Figure 5 This is a cross-sectional view showing a device for tightening a flexible workpiece with fine threads according to an embodiment of the present invention; Figure 6 This is an exploded view of a horizontal floating mechanism according to an embodiment of the present invention.

[0032] like Figures 1 to 6 As shown, a device for tightening fine-thread flexible workpieces, including internal thread workpieces and external thread workpieces, is provided. The device includes: a alignment guide mechanism 8, a horizontal floating mechanism 9, a support mechanism, and a screwing mechanism.

[0033] The alignment guide mechanism 8 has a cavity in the middle of the base and a pair of X-direction linear slide rails 86 on the upper part. On the slide rails are alignment front slide plate 85 and alignment rear slide plate 84 that can run relative to each other. The alignment front slide plate 85 and alignment rear slide plate 84 have semi-circular grooves on adjacent sides. The inner diameter of the circular hole formed by the two semi-circular grooves is larger than the outer diameter of the cross-section of the flexible workpiece with fine thread to be tightened.

[0034] A horizontal floating mechanism 9 is installed in the alignment guide mechanism 8 for mounting the internal thread workpiece to be tightened. The horizontal floating mechanism 9 includes a floor that contacts the base, and a fixed plate 96, a transverse floating plate 94, and an internal thread workpiece clamping block arranged sequentially from bottom to top. The internal thread workpiece clamping block includes a front internal thread workpiece clamping block 92 corresponding to the alignment front slide plate 85 and a rear internal thread workpiece clamping block 91 corresponding to the alignment rear slide plate 84. The fixed plate 96 is provided with a Z-direction transverse linear guide rail 95 to slidely connect the transverse floating plate 94, and the transverse floating plate 94 is provided with an X-direction longitudinal linear guide rail 93 to slidely connect the front internal thread workpiece clamping block 92 and the rear internal thread workpiece clamping block 91, respectively.

[0035] The support mechanism is fixed on one side of the alignment guide mechanism 8 and extends upward in the Y direction. A lifting cylinder 5, an upper limit sensor 6, and a lower limit sensor 7 are installed on the support mechanism.

[0036] The screwing mechanism is mounted on the support mechanism and is driven by the lifting cylinder 5 to move up and down along the Y direction. The mechanism includes a motor 1, a planetary reducer 2, a torque sensor 3, and a universal floating joint mechanism 4 arranged sequentially from top to bottom in the axial direction above the internal thread workpiece. The universal floating joint mechanism 4 is connected to the universal floating joint mechanism 4 via a coaxially connected transmission shaft 42 and bearing 41. The external thread workpiece is hoisted below the universal floating joint mechanism 4.

[0037] According to the device for tightening flexible workpieces with fine threads of this utility model, the workpiece is externally rounded at the tightening joint by the straightening guide mechanism 8, and the screw threads are straightened at the same time to deal with the problem that the internal and external threads cannot be screwed in due to the thin wall deformation of the workpiece.

[0038] This invention can calibrate the inlet of the screw-in workpiece with internal thread and keep the horizontal floating mechanism 9 that fixes the internal thread workpiece in a horizontal free state. At the same time, the screwed-in external thread workpiece adopts a universal floating state, which reduces the error of parallelism between the screw threads processed on the workpiece and the workpiece clamping surface and the cumulative tolerance of the assembly of the tightened and clamped workpiece.

[0039] like Figure 2 As shown, the universal floating joint mechanism 4 includes: a cylindrical external thread workpiece connector 43, an external thread workpiece connecting pin 44 that passes through and connects the external thread workpiece and the lower end of the external thread workpiece connector 43, a universal transmission block 46, a first universal transmission pin 45, and two second universal transmission pins 47.

[0040] According to one or more embodiments of the present invention, the universal drive block 46 is annular, the first universal drive pin 45 passes through and slides in the Z direction to connect the universal drive block 46 and the lower end of the drive shaft 42, and the two second universal drive pins 47 pass through and slide in the Y direction to connect the external thread workpiece connector 43 and the universal drive block 46 respectively to the two sides of the drive shaft 42, thereby realizing universal drive when the external thread workpieces are at the same height.

[0041] According to one or more embodiments of the present invention, the front and rear alignment slides 85 and 84 are respectively connected to the alignment guide cylinder 81 via the alignment guide cylinder connecting rod 82. The front and rear alignment slides 85 and 84 are pushed by the alignment guide cylinder 81 to run in opposite directions along the linear slide rail 86X.

[0042] According to one or more embodiments of the present invention, the alignment guide mechanism 8 further includes: alignment guide blocks 83, there are two alignment guide blocks 83, which are respectively disposed on the semi-circular grooves of the alignment front slide plate 85 and the alignment rear slide plate 84. The alignment guide blocks 83 have arcs concentric with the semi-circular grooves of the alignment front slide plate 85 and the alignment rear slide plate 84, and the inner diameter of the upper end of the alignment guide block 83 is larger than the inner diameter of the lower end, so as to facilitate the introduction of the external threaded workpiece.

[0043] According to one or more embodiments of the present invention, fixing holes are provided on the fixing plate 96, the horizontal floating plate 94, and the internal thread workpiece clamping block. After the horizontal floating mechanism 9 clamps the internal thread workpiece, the horizontal floating switch shaft 97 connected to the horizontal floating switch cylinder 99 passes through the fixing hole to fix the internal thread workpiece.

[0044] According to one or more embodiments of the present invention, the shaping guide mechanism 8 further includes: shaping guide limiting blocks 87, there are two shaping guide limiting blocks 87, which are disposed on both sides of the opening between the front shaping slide plate 85 and the rear shaping slide plate 84, to prevent the front shaping slide plate 85 and the rear shaping slide plate 84 from being over-clamped, and to avoid deformation of the flexible workpiece with fine threads tightened.

[0045] According to one or more embodiments of the present invention, the inner diameter of the hole between the transverse floating plate 94 and the fixed plate 96 for accommodating the internal thread workpiece is greater than 1.2 times the outer diameter of the internal thread workpiece, so as to ensure that the internal thread workpiece does not interfere with the transverse floating plate 94 and the fixed plate 96 when it floats.

[0046] According to one or more embodiments of the present invention, the screwing mechanism further includes a sensing plate 10.

[0047] According to one or more embodiments of the present invention, when the screwing mechanism Y moves up and down, when the sensing plate 10 triggers the upper limit sensor 6, the lifting cylinder 5 stops controlling the screwing mechanism to continue moving up, and when the sensing plate 10 triggers the lower limit sensor 7, the lifting cylinder 5 stops controlling the screwing mechanism to continue moving down.

[0048] According to one or more embodiments of this utility model, the horizontal floating switch shaft 97 has multiple segments with unequal outer diameters along the axial direction, wherein the larger outer diameter segment is a positioning segment that mates with the inner diameter of the fixing hole, and the smaller outer diameter segment is a clearance segment.

[0049] When the horizontal floating switch cylinder 99 pushes the horizontal floating switch shaft 97 upward through the horizontal floating switch cylinder connector 98, the horizontal floating switch shaft 97 is tightly fitted with the fixing hole, so that the front clamping block 92 of the internal thread workpiece, the transverse floating plate 94 and the fixing plate 96 are relatively fixed in position; when the horizontal floating switch cylinder 99 pulls the horizontal floating switch shaft 97 downward through the horizontal floating switch cylinder connector 98, the horizontal floating switch shaft 97 maintains a gap with the fixing hole, so that the front clamping block 92 of the internal thread workpiece can float freely in the longitudinal direction and the transverse floating plate 94 in the transverse direction.

[0050] The device for tightening flexible workpieces with fine threads according to this utility model can tighten soft materials, such as 2A12 aluminum, thin-walled fine internal and external threads, without damaging the threads during the tightening process, and can set the tightening force and the number of turns.

[0051] When using the device described above for tightening flexible workpieces with fine threads, the tightening method includes the following steps:

[0052] In the initial state, the lifting cylinder 5 push-pull rod retracts, and the sensing plate 10 just triggers the upper limit sensor 6; the alignment guide cylinder connecting rod 82 retracts, so that the rear clamping block 91 and the front clamping block 92 of the internal thread workpiece are in the open state.

[0053] Material clamping: Insert the external thread workpiece into the hole of the external thread workpiece connector 43, and then connect it through the external thread workpiece connecting pin 44; clamp the internal thread workpiece through the internal thread workpiece rear clamping block 91 and the internal thread workpiece front clamping block 92, and connect the internal thread workpiece rear clamping block 91 and the internal thread workpiece front clamping block 92 through screws.

[0054] Positioning of the internal thread workpiece: After the internal thread workpiece is clamped, the horizontal floating switch shaft 97 is pushed upward by the extension of the push rod of the horizontal floating switch cylinder 99, which positions the fixed plate 96, the horizontal floating plate 94 and the clamping block before clamping the external thread workpiece.

[0055] The starting device adjusts the electric proportional valve to supply the lifting cylinder 5 with the set air pressure, so that the weight of the entire external thread workpiece clamping device is greater than the upward thrust of the cylinder. In this way, the entire tightening unit will slowly descend to contact the internal thread workpiece. At this time, the sensing plate 10 will trigger the lower limit sensor 7.

[0056] Internal thread alignment and external thread guidance: When the lower limit sensor 7 is triggered, the two alignment and guidance cylinders 81 are activated to push the alignment rear slide plate 84 and the alignment front slide plate 85 to clamp in the middle, thereby aligning the internal thread workpiece and guiding the external thread workpiece.

[0057] After the internal threaded workpiece is fixed at the interface and the external threaded workpiece is aligned, the electric proportional valve automatically adjusts the intake air pressure of the lifting cylinder to move upward, so that the downward gravity of the entire screwing mechanism minus the upward pulling force of the cylinder equals the weight of the external threaded workpiece itself. This ensures that the downward pressure of the first screwing turn is equal to the weight of the external threaded workpiece.

[0058] Start motor 1 and turn it one turn in the opposite direction of the thread, so that the external thread workpiece is completely in contact with the internal thread workpiece under its own weight; after turning it one turn in the opposite direction, start motor 1 and turn it two turns in the forward tightening direction and then stop.

[0059] After turning the cylinder two full turns in the forward direction, the two alignment guide cylinders 81 are activated to return to their original positions, pulling the alignment slide plate 84 and the alignment front slide plate 85 to move to both sides. At the same time, the horizontal floating switch cylinder 99 is activated, pulling the horizontal floating switch cylinder connector 98 to pull the horizontal floating switch shaft 97 downward. This causes the axial clearance section of the horizontal floating switch shaft 97 to correspond to the fixing holes of the internal thread workpiece front clamping block 92 and the transverse floating plate 94, respectively. This maintains a gap between the horizontal floating switch shaft 97 and the internal thread workpiece front clamping block 92 and the transverse floating plate 94, allowing the internal thread workpiece front clamping block 92 to float freely in the longitudinal direction and the transverse floating plate 94 to float freely in the transverse direction. Simultaneously, the electric proportional valve adjusts the air pressure so that the upward pulling force of the cylinder is equal to the total weight of the screwing mechanism plus the external thread workpiece. At this point, the entire tightening mechanism is almost in a zero-gravity state, making the downward pressure of the external thread workpiece on the internal thread workpiece zero.

[0060] Restart motor 1 to tighten. During the tightening process, torque sensor 3 monitors the tightening force in real time until the set number of tightening turns is reached.

[0061] Remove the tightened workpiece to complete the tightening process.

[0062] This invention, through the control of the lifting cylinder 5 and the screwing mechanism, prevents the frictional force during the screwing process from increasing due to excessive or insufficient screwing pressure. This avoids the problems of debris and deformation of the outer wall of the screw after the external threaded workpiece is screwed in, thereby improving processing accuracy, product yield, and production efficiency.

[0063] The above description is merely an exemplary embodiment of the present utility model and is not intended to limit the scope of protection of the present utility model. The scope of protection of the present utility model is determined by the appended claims.

Claims

1. A device for tightening a fine-threaded flexible workpiece, the fine-threaded flexible workpiece comprising an internal thread workpiece and an external thread workpiece, characterized in that, Devices for tightening flexible workpieces with fine threads include: The alignment guide mechanism has a base with a cavity in the middle and a pair of X-direction linear slide rails on the upper part. A front alignment slide plate and a rear alignment slide plate that can run relative to each other are arranged on the slide rails. Semi-circular grooves are opened on the adjacent sides of the front alignment slide plate and the rear alignment slide plate. The inner diameter of the circular hole formed by the two semi-circular grooves is larger than the outer diameter of the cross-section of the flexible workpiece with fine thread to be tightened. A horizontal floating mechanism is provided in the alignment guide mechanism for installing the internal thread workpiece to be tightened. The horizontal floating mechanism includes a floor in contact with the base, and a fixed plate, a horizontal floating plate, and an internal thread workpiece clamping block arranged sequentially from bottom to top. The internal thread workpiece clamping block includes a front internal thread workpiece clamping block corresponding to the front alignment slide plate and a rear internal thread workpiece clamping block corresponding to the rear alignment slide plate. The fixed plate is provided with a Z-direction horizontal linear guide rail to slidely connect the horizontal floating plate, and the horizontal floating plate is provided with an X-direction longitudinal linear guide rail to slidely connect the front internal thread workpiece clamping block and the rear internal thread workpiece clamping block, respectively. A support mechanism is fixed to one side of the alignment guide mechanism and extends upward in the Y direction. A lifting cylinder, an upper limit sensor, and a lower limit sensor are installed on the support mechanism. The screwing mechanism is mounted on the support mechanism and is driven by a lifting cylinder to move up and down along the Y direction. It includes a motor, a planetary reducer, a torque sensor, and a universal floating joint mechanism arranged sequentially from top to bottom in the axial direction above the internal thread workpiece. The universal floating joint mechanism is connected to the universal floating joint mechanism through a coaxially connected transmission shaft and bearing. The external thread workpiece is suspended below the universal floating joint mechanism.

2. The device for tightening flexible workpieces with fine threads as described in claim 1, characterized in that, The universal floating joint mechanism includes: a cylindrical external thread workpiece connector, an external thread workpiece connecting pin that passes through and connects the external thread workpiece and the lower end of the external thread workpiece connector, a universal transmission block, a first universal transmission pin, and two second universal transmission pins.

3. The device for tightening flexible workpieces with fine threads as described in claim 2, characterized in that, The universal drive block is circular. The first universal drive pin passes through and slides between the universal drive block and the lower end of the drive shaft in the Z direction. The two second universal drive pins pass through and slide between the external thread workpiece connector and the universal drive block in the Y direction on both sides of the drive shaft, thereby realizing universal drive when the external thread workpiece is at the same height.

4. The device for tightening flexible workpieces with fine threads as described in claim 1, characterized in that, The front and rear alignment slides are connected to the alignment guide cylinder via alignment guide cylinder connecting rods. The front and rear alignment slides are pushed by the alignment guide cylinder to run in opposite directions along the X-axis of the linear slide rail.

5. The device for tightening flexible workpieces with fine threads as described in claim 1, characterized in that, The alignment guide mechanism further includes: alignment guide blocks, there are 2 alignment guide blocks, which are respectively set on the semi-circular grooves of the front alignment slide and the rear alignment slide. The alignment guide blocks have arcs concentric with the semi-circular grooves of the front alignment slide and the rear alignment slide, and the inner diameter of the upper end of the alignment guide block is larger than the inner diameter of the lower end, so as to facilitate the introduction of external threaded workpieces.

6. The device for tightening flexible workpieces with fine threads as described in claim 1, characterized in that, The fixed plate, the horizontal floating plate, and the internal thread workpiece clamping block are provided with fixing holes. After the horizontal floating mechanism clamps the internal thread workpiece, the horizontal floating switch shaft connected to the horizontal floating switch cylinder passes through the fixing holes to fix the internal thread workpiece.

7. The device for tightening flexible workpieces with fine threads as described in claim 1, characterized in that, The straightening guide mechanism further includes: straightening guide limiting blocks, there are 2 straightening guide limiting blocks, which are set on both sides of the opening between the straightening front slide plate and the straightening rear slide plate, to prevent the straightening front slide plate and the straightening rear slide plate from being over-clamped, and to avoid deformation of the flexible workpiece with fine thread tightened.

8. The device for tightening flexible workpieces with fine threads as described in claim 1, characterized in that, The inner diameter of the hole between the horizontal floating plate and the fixed plate for accommodating the internal threaded workpiece is 1.2 times larger than the outer diameter of the internal threaded workpiece, so as to ensure that the internal threaded workpiece does not interfere with the horizontal floating plate and the fixed plate when it floats.

9. The device for tightening flexible workpieces with fine threads as described in claim 1, characterized in that, The screwing mechanism also includes a sensing plate.

10. The device for tightening flexible workpieces with fine threads as described in claim 9, characterized in that, When the screwing mechanism Y moves up and down, when the sensing plate triggers the upper limit sensor, the lifting cylinder stops controlling the screwing mechanism to continue moving up; when the sensing plate triggers the lower limit sensor, the lifting cylinder stops controlling the screwing mechanism to continue moving down.

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