Triaxial self-locking nut and constant value deformation tensioner

Abstract

The application discloses a three-axis self-locking nut, comprising a nut body, a threaded hole arranged in the middle of the nut body in the axial direction; the threaded hole comprises a first threaded section, a second threaded section and a third threaded section connected in sequence; the corresponding axes of the first threaded section, the second threaded section and the third threaded section are mutually deviated. By arranging the threaded hole in the middle of the nut body in the axial direction, compared with the traditional split self-locking nut structure, the threaded self-locking anti-loosening can be realized on the full threaded length. The application further discloses a constant-value deformation tension device, which can produce deformation by applying a constant-value driving force to pull the blank, so that the three-axis self-locking nut can be produced according to the deformation amount of the blank.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of fasteners, in particular to a three-axis self-locking nut. BACKGROUND

[0002] As a kind of fastener, nut requires firm fastening and cannot be loosened. Due to the influence of cold and hot changes of working environment and vibration, nut fastening loosening often causes accidents. In order to prevent this phenomenon, people use various measures such as double nut connection, spring washer, open-end pin, changing pitch, stop washer, open nut and installing stop pin. Although these measures can prevent nut loosening to some extent, these anti-loosening measures still have problems such as loosening, complex process, damaging thread and high operation difficulty. Therefore, there is an urgent need for a nut that is easy to process and has strong self-locking ability. SUMMARY

[0003] One of the purposes of the present application is to provide a three-axis self-locking nut that is easy to process and has strong self-locking ability.

[0004] Another purpose of the present application is to provide a fixed value deformation tension device that can dislocate the above-mentioned three-axis self-locking nut.

[0005] To achieve at least one of the above purposes, the technical solution adopted by the present application is as follows: a three-axis self-locking nut, comprising a nut body, a threaded hole is arranged in the middle of the nut body along the axial direction; the threaded hole comprises a first threaded section, a second threaded section and a third threaded section connected in sequence; the corresponding axes of the first threaded section, the second threaded section and the third threaded section are offset from each other, so that when the nut body is connected with a bolt, the self-locking ability of the nut body can be effectively improved.

[0006] Preferably, the corresponding axes of the first threaded section and the third threaded section are equidistantly offset from the axis of the second threaded section along the axial direction.

[0007] Preferably, the corresponding axes of the first threaded section and the third threaded section coincide with each other; at the same time, the axis of the second threaded section is eccentric to the coinciding axis of the first threaded section and the third threaded section.

[0008] Preferably, the nut body comprises an upper locking part, a deformation section and a lower locking part connected in sequence; the first threaded section, the second threaded section and the third threaded section are arranged in the upper locking part, the deformation section and the lower locking part in sequence; the nut body is adapted to be deformed through the deformation section, so that the corresponding axes of the first threaded section, the second threaded section and the third threaded section are offset from each other.

[0009] The utility model provides a constant value deformation tensile force device, including drive part, tow part and base plate, be provided with the placement cavity between the tow part and the base plate, the placement cavity is used for placing the blank for producing the three -axis self -locking nut, the drive part is suitable for driving the tow part to slide along the base plate through the set constant value driving force, and then the tow part can drive the blank to deform, thereby according to the deformation of the blank for the production of the three -axis self -locking nut.

[0010] Preferably, the placement cavity includes a positioning cavity and a towing cavity, the positioning cavity is provided on the base plate for positioning the part of the blank, and the towing cavity is provided on the tow part for cooperating with the remaining part of the blank; the tow part is threadedly connected with the drive part, so that the rotation of the drive part drives the tow part to slide along the base plate, thereby the blank is pulled to deform through the towing cavity.

[0011] Preferably, the tow part includes a pull plate and a threaded rod, the towing cavity is provided on the pull plate, the pull plate is slidingly provided on the base plate, so that the threaded rod penetrates through the through hole on one side of the base plate and is threadedly connected with the drive part, thereby under the rotation of the drive part, the pull plate can slide along the base plate to pull the blank to deform.

[0012] Preferably, the base plate includes a support plate and a vertical plate perpendicular to each other, the positioning cavity is provided on the support plate, and the through hole is provided on the vertical plate.

[0013] Preferably, the drive part includes a scale nut and a hand wheel, the scale nut is threadedly connected with the threaded rod, and the hand wheel is fixed on the side of the scale nut, so that the scale nut is conveniently rotated through the hand wheel.

[0014] Preferably, a scale is circumferentially provided on the hand wheel, and a scale plate is fixedly installed on the base plate, so that the scale value on the hand wheel is read through the scale plate, thereby the deformation of the blank is directly obtained.

[0015] Preferably, a damping block is also adapted to be placed in the placement cavity, so that the space of the placement cavity is changed by placing the damping block of different sizes in the placement cavity, thereby the blank of different sizes is placed, thereby the deformation of the blank of different sizes by the constant value deformation tensile force device is measured.

[0016] Compared with the prior art, the utility model has the beneficial effects that:

[0017] (1) by the nut body middle part threaded hole is segmented axis offset setting, compared with the traditional split structure, can realize the full thread length on the thread self-locking anti-loose.

[0018] (2) the offset distance of the axis between each thread segment corresponding to the threaded hole is calculated by setting the torque, which can ensure that the thread will not be damaged during use, thereby realizing repeated use.

[0019] (3) the offset distance of the axis between each thread segment corresponding to the threaded hole can be different according to different torque, so that the self-locking locking torque of the thread can be adjusted according to the different offset distance of the axis between each thread segment corresponding to the threaded hole when the bolt and the nut body are used.

[0020] (4) simple processing, convenient to use and wide application range, without the cooperation of cap or spring washer and the like.

[0021] (5) the deformation amount required by the three-axis self-locking nut can be easily measured by the constant value deformation tension device, and the measurement result is more accurate. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is the structure diagram of the nut body in the application.

[0023] Figure 2 is the force analysis diagram of the nut body in the application Figure 1 .

[0024] Figure 3 is the force analysis diagram of the nut body in the application Figure 2 .

[0025] Figure 4 is the overall structure diagram of the constant value deformation tension device in the application.

[0026] Figure 5 is the installation structure diagram of the base plate and the scale plate in the application.

[0027] Figure 6 is the structure diagram of the traction part in the application.

[0028] Figure 7 is the structure diagram of the driving part in the application.

[0029] Figure 8 is the axial structure diagram of the driving part in the application.

[0030] Figure 9 is the structure diagram of the different size damping block installed in the placement cavity in the application.

[0031] In the figure: Nut body 1, threaded hole 100, upper locking part 11, deformation section 12, lower locking part 13, first threaded section 110, second threaded section 120, third threaded section 130, placement cavity 200, base plate 21, support plate 211, vertical plate 212, positioning cavity 2101, through hole 2102, traction part 22, pull plate 221, threaded rod 222, traction cavity 2201, drive part 23, scale nut 231, handwheel 232, scale plate 24, damping block 25. Detailed Implementation

[0032] The present application will be further described below with reference to specific embodiments. It should be noted that, without conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments.

[0033] In the description of this application, it should be noted that the directional terms such as "center", "lateral", "longitudinal", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", and "counterclockwise" indicate the orientation and positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. They should not be construed as limiting the specific protection scope of this application.

[0034] It should be noted that the terms "first," "second," etc., in the specification and claims of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0035] One aspect of this application provides a triaxial self-locking nut, such as... Figures 1 to 3 As shown, one preferred embodiment includes a nut body 1. A threaded hole 100 is axially provided in the middle of the nut body 1. The threaded hole 100 includes a first threaded segment 110, a second threaded segment 120, and a third threaded segment 130 connected sequentially; the axes of the first threaded segment 110, the second threaded segment 120, and the third threaded segment 130 are offset from each other. Therefore, when the nut body 1 is connected to a bolt through the threaded hole 100, the external thread of the bolt can self-lock with the full threaded segment of the threaded hole 100, thereby effectively improving the self-locking capability of the nut body 1.

[0036] In this embodiment, there are multiple specific deviations of the axes between the first threaded segment 110, the second threaded segment 120, and the third threaded segment 130, which can be described in the following two ways.

[0037] Method 1, such as Figure 1 andFigure 2 As shown, the axes corresponding to the first thread segment 110 and the third thread segment 130 are axially equidistant from the axis of the second thread segment 120. That is, the projections of the axes corresponding to the first thread segment 110 and the third thread segment 130 onto the axis of the second thread segment 120 are equal in length, and the angle between the line connecting the axis of the first thread segment 110 and the axis of the third thread segment 130 to the axis of the second thread segment 120 is 180°.

[0038] It can be understood that the projections of the axes corresponding to the first thread segment 110 and the third thread segment 130 onto the axis of the second thread segment 120 can also be different in length, and the angle between the line connecting the axis of the first thread segment 110 and the axis of the third thread segment 130 to the axis of the second thread segment 120 can also be less than 180°. However, when the threaded hole 100 is connected with the bolt, uneven stress is prone to occur, thereby reducing the service life of the first thread segment 110 to the third thread segment 130, and even exacerbating the failure of the threads.

[0039] It can also be understood that in the present mode, when the threaded hole 100 is connected with the bolt, the first thread segment 110 and the third thread segment 130 are respectively in interference fit with the two sides of the bolt; at this time, the second thread segment 120 is used for smoothly transitioning the first thread segment 110 and the third thread segment 130.

[0040] In mode two, the axes corresponding to the first thread segment 110 and the third thread segment 130 coincide with each other; at the same time, the axis of the second thread segment 120 is eccentric to the axis where the first thread segment 110 and the third thread segment 130 coincide.

[0041] It can be understood that the present mode will also have a smooth transition between adjacent thread segments, so the present mode can be regarded as a double-layer structure of mode one.

[0042] In one embodiment of the present application, as shown in Figure 1 and Figure 2 The nut body 1 includes an upper locking portion 11, a deformation section 12, and a lower locking portion 13 connected in sequence. The first thread segment 110, the second thread segment 120, and the third thread segment 130 are correspondingly provided in the upper locking portion 11, the deformation section 12, and the lower locking portion 13 in sequence. The diameter of the deformation section 12 is smaller than the diameters of the upper locking portion 11 and the lower locking portion 12, so that the nut body 1 can be deformed through the deformation section 12 to offset the axes corresponding to the first thread segment 110, the second thread segment 120, and the third thread segment 130 from each other.

[0043] It can be understood that if the structure of the threaded hole 100 adopts the above-mentioned way one, when the deformation section 120 is deformed, one of the upper locking part 11 and the lower locking part 13 can deviate relative to the other with the deformation of the deformation section 120, so that the threaded hole 100 is three-axially eccentric, so as to realize the three-axial self-locking of the threaded hole 100 when connected with the bolt.

[0044] If the structure of the threaded hole 100 adopts the above-mentioned way two, when the deformation section 120 is deformed, the upper locking part 11 and the lower locking part 13 remain stationary at the same time, so that the threaded hole 100 can be three-axially self-locked when connected with the bolt.

[0045] The self-locking principle of the threaded hole 100 will be described in detail below, taking the structure of way one as an example.

[0046] As shown in Figure 1 and Figure 2 , it is assumed that the eccentric distance of the axis of the first threaded section 110 and the third threaded section 130 relative to the axis of the second threaded section 120 is e.

[0047] As shown in Figure 2 , when the threaded hole 100 is connected with the bolt, the axes of the first threaded section 110 and the second threaded section 130 deviate to both sides of the axis of the second threaded section 120, so that one side of the first threaded section 110 can be interference fit with one side of the upper part of the bolt, and one side of the third threaded section 130 can be interference fit with the other side of the lower part of the bolt. At this time, the uniformly distributed positive pressure of the interference side of the first threaded section 110 on the upper part of the bolt is G 上 , and the uniformly distributed positive pressure of the interference side of the third threaded section 110 on the lower part of the bolt is G 下 .

[0048] As shown in Figure 3 , with the continuous screwing of the bolt and the threaded hole 100 on the nut body 1, the positive pressure of the interference side of the first threaded section 110 and the third threaded section 130 on the bolt can respectively obtain the friction force F 上 and F 下 of the threaded hole 100 on the bolt in the circumferential direction. At this time, F 上 = μ·G 上 ·sinα, F 下 = μ·G 下 ·sinα, where μ is the friction coefficient of the threaded hole 100 and the bolt, and α is the helix angle of the internal thread on the threaded hole 100 and the external thread on the bolt.

[0049] Since the friction forces F 上 and F 下 are in the same direction in the circumferential direction, the friction force F上 and F 下 The resistance moment M formed is M = (F 上 +F 下 )·d / 2; wherein d is the nominal diameter of the bolt or the threaded hole 100.

[0050] Since the axes of the first threaded section 110 and the third threaded section 130 are equidistantly eccentric to the axis of the second threaded section 120. Generally, F 上 and F 下 can be considered equal, i.e. F 上 =F 下 =F, so that M = F·d.

[0051] The resistance moment M obtained above will hinder the nut body 1 from loosening throughout, so as to realize self-locking of the nut body 1 to the bolt.

[0052] It can be understood that, when a common straight bolt is threadedly connected with a common nut, it is generally a clearance fit. Therefore, in the present application, the bolt is still a common straight bolt, so that when the threaded hole 100 is threadedly connected with the bolt, due to the eccentric arrangement of the corresponding threaded sections on the threaded hole 100, the first threaded section 110 and the third threaded section 130 are in interference fit on one side with the bolt, and the clearance amount of the other side of the first threaded section 110 and the third threaded section 130 with the bolt becomes larger.

[0053] Meanwhile, when the threaded hole 100 is connected with the bolt, the main influencing factor of the normal pressure of the nut body 1 to the bolt is the eccentricity e, i.e. the greater the value of the eccentricity e, the greater the resistance moment M obtained finally. However, if the resistance moment M is too large, it will damage the internal thread of the threaded hole 100 and the external thread on the bolt in the process of rotating the nut body 1. Therefore, the value of the eccentricity e should be reasonable.

[0054] In order to solve the problem of the value of the eccentricity e, another aspect of the present application provides a constant-value deformation tension device, as shown in Figures 4 to 9 , wherein a preferred embodiment comprises a driving part 23, a pulling part 22 and a base plate 21. A placing cavity 200 is arranged between the pulling part 22 and the base plate 21, and the placing cavity 200 is used for placing a blank for producing the three-axis self-locking nut described above; the driving part 23 can drive the pulling part 22 to slide along the base plate 21 by a set constant driving force, and then the pulling part 22 can drive the blank to deform, so as to obtain a suitable value of the eccentricity e according to the deformation amount of the blank for the production of the three-axis self-locking nut.

[0055] It can be understood that according to the size of the threaded hole 100 and the related parameters, the resistance torque M required for the nut body 1 to self-lock the bolt can be calculated. Then according to the resistance torque M, the value G of the normal pressure generated by the axial eccentricity of each thread segment on the threaded hole 100 can be deduced. The value G of the normal pressure is the traction force when the traction part 22 pulls the blank to deform in the constant value deformation tension device, and the driving force of the driving part 23 driving the traction part 22 can be obtained by conversion. That is, in the case of knowing the normal pressure G, the driving force of the driving part 23 is a constant value.

[0056] It should be understood that since the placement cavity 200 is used to place the blank for producing the three-axis self-locking nut, the cross-sectional shape and size of the placement cavity 200 are adapted to the three-axis self-locking nut.

[0057] In this embodiment, as shown in Figure 5 and Figure 6 The placement cavity 200 includes a positioning cavity 2101 and a traction cavity 2201, the positioning cavity 2101 is arranged on the base plate 21 for positioning a part of the axial segment of the blank, and the traction cavity 2201 is arranged on the traction part 22 for cooperating with the remaining axial segment of the blank. The traction part 22 can be threadedly connected with the driving part 23, so that the rotation of the driving part 23 drives the traction part 22 to slide along the base plate 21, thereby pulling the blank to deform through the traction cavity 2201.

[0058] It can be understood that if the structure of the threaded hole 100 is as described in the first mode above, the positioning cavity 2101 is used to position the part of the blank corresponding to the lower locking part 13, and the traction cavity 2201 is used to cooperate with the part of the blank corresponding to the upper locking part 13, so that the upper locking part 11 is driven to be deflected relative to the lower locking part 13 through the traction cavity 2201. Since the stiffness of the upper locking part 11 is much greater than the stiffness of the deformation section 12, the deflection of the upper locking part 11 is caused by the deformation of the deformation section 12.

[0059] If the structure of the threaded hole 100 is as described in the second mode above, the positioning cavity 2101 is used to position the parts of the blank corresponding to the upper locking part 11 and the lower locking part 13, respectively, and the traction cavity 2201 is used to cooperate with the part of the blank corresponding to the deformation section 12, so that the deformation section 12 can be driven to be radially offset relative to the upper locking part 11 and the lower locking part 13 through the traction cavity 2201.

[0060] It can also be understood that the cross-sectional shape of the positioning cavity 2101 is adapted to the upper and lower end cross-sectional shape of the blank, which is generally a regular hexagon. Since the traction part 22 is used to pull the blank to generate deflection, the size of the traction cavity 2201 along the deflection direction is larger than the cross-sectional size of the blank, so as to avoid interference between the traction cavity 2201 along the deflection direction and the blank. At the same time, the shape of one side of the traction cavity 2201 for pulling the blank is adapted to the blank, so as to ensure that the traction cavity 2201 is uniformly stressed when pulling.

[0061] In the embodiment, as shown in Figure 4 and Figure 6 , the traction part 22 includes a pull plate 221 and a threaded rod 222, and the threaded rod 222 is vertically fixed to one side of the pull plate 221. The traction cavity 2201 is arranged on the pull plate 221, and the pull plate 221 is slidingly arranged on the base plate 21. Meanwhile, the threaded rod 222 is threadedly connected with the driving part 23 through the through hole 2102 arranged on one side of the base plate 21. Thus, under the thread engagement of the driving part 23, the pull plate 221 can slide along the base plate 21 to pull the blank to generate deformation.

[0062] In the embodiment, as shown in Figure 5 , the base plate 21 includes a support plate 211 and a vertical plate 212 which are perpendicular to each other, the positioning cavity 2101 is arranged on the support plate 211, and the through hole 2102 is arranged on the vertical plate 212.

[0063] It can be understood that if the constant value deformation tension device of the present application is used to measure and produce the structure of the threaded hole 100 in the above-mentioned mode one. As shown in Figure 5 , the support plate 211 is one piece, and the support plate 211 and the vertical plate 212 are arranged in an L shape, at this time, the support plate 211 is horizontally arranged, the vertical plate 212 is vertically arranged, and the pull plate 221 is horizontally arranged on the upper end surface of the support plate 211. Thus, when the blank is placed in the placement cavity 100, the lower part of the blank is positioned and matched with the positioning cavity 2101, and the upper part of the blank is deflected relative to the lower part of the blank under the cooperation and pulling of the traction cavity 2201.

[0064] If the constant value deformation tension device of the present application is used to measure and produce the structure of the threaded hole 100 in the above-mentioned mode two. The support plate 211 is two pieces, so that the vertical plate 212 is vertically arranged on one side of the two support plates 211, so that the two support plates 211 are horizontally and parallelly arranged. At this time, the pull plate 221 can be slidingly arranged in the region between the two support plates 211.

[0065] In the embodiment, as shown in Figure 7 , the driving part 23 includes a scale nut 231 and a hand wheel 232, the scale nut 231 is threadedly matched with the threaded rod 222, and the hand wheel 232 is fixed to the side of the scale nut 231, so that the scale nut 231 is conveniently screwed by the hand wheel 232.

[0066] In this embodiment, as shown in Figure 8 The hand wheel 232 is provided with a scale, and the scale plate 24 is fixedly installed on the base plate 21, so that after the blank is deflected, the corresponding scale value on the hand wheel 232 is read through the scale plate 24, so that the deformation amount of the blank can be directly obtained.

[0067] The specific working process of the constant value deformation tension device of the present application is as follows:

[0068] First of all, it should be understood that the difference between the blank and the nut body 1 of the three-axis self-locking nut is that the blank has not been deflected, and at this time the threaded hole 100 in the blank is a straight threaded section.

[0069] (1) Place the blank to be measured in the placement cavity 100, rotate the hand wheel 232 until the backlash of the scale nut 231 is eliminated, and record the scale value of the scale plate 24 at this time.

[0070] (2) According to the reasonable resistance torque M value of the three-axis self-locking nut, the driving force required by the driving part 23 is converted.

[0071] (3) Drive the scale nut 231 and the threaded rod 222 to be screwed by applying a constant driving force to the hand wheel 232. As the scale nut 231 continues to rotate, the threaded rod 222 can drive the pull plate 221 to drive the blank to deform until the hand wheel 232 cannot continue to rotate under the constant driving force.

[0072] (4) At this time, record the scale value of the hand wheel 232 opposite the scale plate 24, and subtract the scale value recorded in step (1) to obtain the deformation value of the blank X, X=2e.

[0073] It can be understood that the pitch P of the thread of the scale nut 231 and the threaded rod matched with each other is greater than twice the eccentric distance e, that is, P>X, so that the hand wheel 232 can measure the eccentric distance e under the condition that the rotation angle is less than 360° under the constant driving force.

[0074] In one embodiment of the present application, as shown in Figure 4 and Figure 9 The placement cavity 200 can also place a damping block 25, so that by placing different sizes of damping blocks 25 in the placement cavity 200 to change the space of the placement cavity 200, it is used for placing different sizes of blanks, so that the constant value deformation tension device can measure the deformation amount of blanks of different sizes.

[0075] It can be understood that, as Figure 9As shown, the axial projection of the placement cavity 200 is a regular hexagon. Meanwhile, one side of the resistance block 25 is shaped as a 120° V shape, so that when the resistance block 25 of different widths is placed in the placement cavity 200, the V-shaped side of the resistance block 25 and one of the opposite V-shaped sides of the placement cavity 200 can form a placement cavity 200 that is suitable for different sizes of the blank. Thus, the measurement of the required eccentricity e of different sizes of the blank can be realized by a single fixed value deformation tensioner, for the production of different sizes of three-axis self-locking nuts.

[0076] The above describes the basic principles, main features and advantages of the present application. Those skilled in the art should understand that the present application is not limited to the above-mentioned embodiments, and the above-mentioned embodiments and descriptions in the specification are only the principles of the present application. Without departing from the spirit and scope of the present application, various changes and improvements can be made to the present application, and these changes and improvements all fall within the scope of the claimed present application. The scope of protection claimed by the present application is defined by the appended claims and their equivalents.

Claims

1. A three-start self-locking nut comprising a nut body, characterised in that: The middle part of the nut body is provided with a threaded hole in the axial direction; the threaded hole comprises a first threaded section, a second threaded section and a third threaded section connected in sequence; the corresponding axes of the first threaded section, the second threaded section and the third threaded section are offset from each other; The corresponding axes of the first threaded section and the third threaded section are equidistantly offset from the axis of the second threaded section in the axial direction; When the threaded hole is connected with a bolt, one side of the first threaded section and one side of the upper part of the bolt are in interference fit, while one side of the third threaded section and the other side of the lower part of the bolt are in interference fit; the positive pressure of the first threaded section and the third threaded section on the bolt through the interference side causes the nut body to generate a resistance torque for self-locking in the circumferential direction of the bolt; The nut body comprises an upper locking part, a deformation section and a lower locking part connected in sequence; the first threaded section, the second threaded section and the third threaded section are arranged in the upper locking part, the deformation section and the lower locking part in sequence; the nut body is adapted to deform through the deformation section, so that the corresponding axes of the first threaded section, the second threaded section and the third threaded section are offset from each other.

2. Constant deformation tensioner, characterized in that It comprises: a base plate; a traction part mounted on the base plate; a placement cavity is provided between the traction part and the base plate; and a driving part adapted to drive the traction part to slide along the base plate by a set of fixed value driving force; wherein the placement cavity is used to place a blank for producing the triaxial self-locking nut as claimed in claim 1; the traction part is adapted to deform the blank by sliding along the base plate, and then produce the triaxial self-locking nut according to the deformation amount of the blank.

3. The fixed value deformation tensile device of claim 2, wherein: The placement cavity comprises a positioning cavity and a traction cavity; the positioning cavity is arranged on the base plate to position a part of the shaft section of the blank, and the traction cavity is arranged on the traction part to cooperate with the remaining shaft section of the blank; the traction part is threadedly connected with the driving part, so that the rotation of the driving part drives the traction part to slide along the base plate, and then deforms the blank through the traction cavity.

4. The fixed value deformation tensile device of claim 3, wherein: The traction part comprises a pull plate and a threaded rod; the traction cavity is arranged on the pull plate, the pull plate is slidingly arranged on the base plate, one end of the threaded rod is fixedly connected with the pull plate, and the other end of the threaded rod penetrates through a through hole on one side of the base plate and is threadedly connected with the driving part.

5. The fixed value variable tensile device of claim 4, wherein: The driving part comprises a scale nut and a hand wheel; the scale nut is threadedly connected with the threaded rod, and the hand wheel is fixedly connected with the side of the scale nut.

6. The fixed value variable tensile device of claim 5, wherein: The hand wheel is circumferentially provided with a scale; a scale plate is fixedly mounted on the base plate, so that the scale value on the hand wheel is read through the scale plate, and then the deformation amount of the blank is directly obtained.

7. The fixed value variable tensioning device of claim 2 wherein: The placement cavity is also adapted to place a damping block, so that the space of the placement cavity is changed by placing different sizes of the damping block in the placement cavity, and then different sizes of the blank are placed.

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