CN117329239B - Axial positioning structure of rotary mechanical part - Google Patents
Axial positioning structure of rotary mechanical part Download PDFInfo
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- CN117329239B CN117329239B CN202311480221.9A CN202311480221A CN117329239B CN 117329239 B CN117329239 B CN 117329239B CN 202311480221 A CN202311480221 A CN 202311480221A CN 117329239 B CN117329239 B CN 117329239B
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- 210000003781 tooth socket Anatomy 0.000 description 3
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Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
- F16C35/00—Rigid support of bearing units; Housings, e.g. caps, covers
- F16C35/04—Rigid support of bearing units; Housings, e.g. caps, covers in the case of ball or roller bearings
- F16C35/06—Mounting or dismounting of ball or roller bearings; Fixing them onto shaft or in housing
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
- F16C35/00—Rigid support of bearing units; Housings, e.g. caps, covers
- F16C35/04—Rigid support of bearing units; Housings, e.g. caps, covers in the case of ball or roller bearings
- F16C35/06—Mounting or dismounting of ball or roller bearings; Fixing them onto shaft or in housing
- F16C35/063—Fixing them on the shaft
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Abstract
The invention discloses an axial positioning structure of a rotary mechanical part, which comprises a shaft and a nut, wherein the shaft is provided with common external threads, the inner side of the nut is provided with internal threads, the nut is connected with a positioning part of the shaft, and the positioning part is only provided with the common external threads; the thread root of the internal thread design thread is arc-shaped and tangent to two sides of the thread groove of the internal thread, and the arc of the thread root of the internal thread is in contact screwing with the intersection line of two spirals of the common external thread. The structure can change the sequence of the internal common external thread tooth entering the working bearing, so that the internal common external thread tooth enters the bearing in reverse sequence, thereby realizing the effects that each thread buckle of the thread pair is uniformly loaded, and the normal force is at least more than 2.4 times of the axial force of the thread.
Description
Technical Field
The invention relates to the technical field of axial positioning of mechanical parts, in particular to an axial positioning structure of a rotary mechanical part.
Background
The rotating mechanical parts are mounted on the shaft or spindle to maintain the fixed shaft in rotation. The shaft is positioned with and rotates in bearings and serves to transmit torque along its axis and to support rotating mechanical parts.
The positioning of the bearing inner ring in the axial positioning of the bearing is usually performed by nut positioning, spring retainer positioning, thrust washer positioning, sleeve positioning, bearing positioning with taper in an inner hole, special positioning and the like, and in order to prevent the nut from loosening in the rotating process during nut positioning, technical measures for preventing loosening are required to be taken, the nut and the stop washer positioning are used, key teeth in the stop washer are placed into key grooves of a shaft, and one of teeth on the outer ring of the key teeth is bent into a notch of the nut; the positioning of the locking sleeve is performed by using a nut and a stop washer for the locking sleeve, and the friction force of the nut for locking the locking sleeve is used for positioning the bearing; the bearing with taper in the inner hole needs to make the axial load tightly support the shaft and the bearing, and the mounting needs to pay attention to the direction of taper of the inner hole, for example, the bearing is positioned at the shaft end and is allowed to be processed into threads at the shaft end, the bearing can be directly positioned by a nut, if the bearing is not mounted at the shaft end and is not allowed to be processed into threads on the shaft, in this case, two half combined threaded rings are also needed to be clamped into grooves of the shaft, and then the bearing is positioned by the nut.
The on-shaft parts should have a defined position. The fixing of the parts on the shaft in the axial direction is to prevent the parts from moving axially. The round nut and the lock washer ensure that the part is reliably fixed in an axial fixing mode on the shaft and can bear large axial force; the shaft needs to be cut with threads and longitudinal grooves, has great stress concentration and can reduce the fatigue resistance of the shaft, so the shaft is commonly used for fixing shaft end parts, and fine threads are commonly used. When the double round nut structure is used for fixing the middle part, the screw threads weaken the strength of the shaft greatly and the stress concentration is serious although the double round nut structure can bear larger axial force.
The engineering machinery speed reducing and rotating device needs frequent change of rotation speed, braking, bearing vibration and axial component force caused by abrupt load change and the like, so that an axial positioning device in the supporting speed change and torque output device is separated from an ideal original assembly position. The technical measures of looseness prevention are adopted, nuts and flanges are integrally combined and positioned, after the bearing achieves pretightening force and the adjustment of the play of the rolling bearing is basically guaranteed, part of flanges are placed into key grooves of the shaft under the action of external force, and the purpose of mechanical locking and looseness prevention is achieved.
However, the device only achieves basic functions, such as basic positioning position, basic pretightening force and basic axial play adjustment; meanwhile, the longitudinal groove is formed on the shaft, so that the effective use diameter of the shaft is reduced, stress concentration is caused, and the like; furthermore, because of the round nut and the lock washer or the nut and flange structure, the internal teeth of the washer are embedded into the grooves on the shaft, and one of the external teeth is bent into the notch of the nut or the flange is embedded into the groove on the shaft under the action of external force, which brings great inconvenience to maintenance.
Therefore, a new axial positioning structure for rotating machine parts is needed, which can solve the above-mentioned problems.
Disclosure of Invention
The invention aims to provide an axial positioning structure of a rotary mechanical part, which aims at realizing axial positioning and adjustable clearance of the rotary mechanical part, and simultaneously can realize self-locking and anti-loose axial positioning structure, and realize that one part is used for replacing the traditional two parts, and a longitudinal groove is processed on a shaft is canceled, so that the design structure has high normal friction force and position compensation thereof through optimal design, and achieves the effects of accurate positioning, locking and anti-loose, simple installation, convenient maintenance, high fatigue strength and high fatigue life, low cost and multiple effects of disassembly and assembly times without reduction.
According to a first aspect of the present invention, there is provided an axial positioning structure of a rotary machine part, comprising a shaft provided with a common external thread and a nut provided with an internal thread inside, the nut being connected to a positioning portion of the shaft provided with only the common external thread; the thread root of the internal thread design thread is arc-shaped and tangent to two sides of the thread groove of the internal thread, and the arc of the thread root of the internal thread is in contact screwing with the intersection line of two spirals of the common external thread.
Preferably, the internal thread root arc is of a variable wedge structure and has pitch error compensation and is in a regular change of inverse gradual widening along the thread axis.
Preferably, the virtual pitch line of the internal thread is separated from the pitch line of the common external thread, so as to realize the following formula:
D2＝d2+2×h1；
Wherein D 2 is the virtual pitch diameter of the internal thread, D 2 is the pitch diameter of the common external thread, and h 1 is the separation distance between the virtual pitch diameter of the internal thread and the pitch diameter of the common external thread.
Preferably, the flank angle of the internal thread is: 35 DEG > alpha > 30 DEG, and the profile angle of the internal thread is 70 DEG > 2 alpha > 60 deg.
Preferably, the design profile of the internal thread consists of a continuous circular arc curve tangent to both sides of the tooth socket, and the radius of the circular arc curve is not less than 0.15011P and not more than 0.18042P.
According to a second aspect of the present application, there is provided a rotary machine employing the axial positioning structure of the above-described rotary machine component.
According to one embodiment of the present disclosure, the axial positioning structure is adopted, starting from the reason of the uneven load distribution of the threaded connection, ensuring that the loading of each thread tooth buckle is basically uniform under the effective screwing length, overcoming the defects of large loading of three buckles before the common thread, easy plastic deformation of the thread tooth buckle, and the like, and fully playing the bearing capacity of each thread tooth buckle.
Under the condition of ensuring that the pitch of the internal common external thread is unchanged, the thread bottom of the internal thread is corrected, and the arc radius is tangent to two sides of the thread groove thread bottom of the internal thread to form a design thread shape of the internal thread, so that the thread bottom spiral arc of the design thread shape of the internal thread is tightly contacted and screwed with two spiral line intersections (namely two thread tips) of the common external thread, the internal thread bottom arc is of a variable-pitch wedge structure and has pitch error compensation and is in a regular change of reverse gradual widening along the thread axis, the sequence of entering the internal common external thread into the work bearing is changed, and the internal thread enters the bearing in reverse sequence, thereby realizing the purposes that each thread buckle of a thread pair is uniformly loaded, and the normal force is at least more than 2.4 times of the axial force of the thread.
Other features of the present invention and its advantages will become apparent from the following detailed description of exemplary embodiments of the invention, which proceeds with reference to the accompanying drawings.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description, serve to explain the principles of the invention.
FIG. 1 is a schematic diagram of a standard male and female thread engagement structure in accordance with an embodiment of the present application;
FIG. 2 is a basic profile of a normal external thread and a basic profile of an internal thread in a threading;
FIG. 3 is a diagram of a normal male thread design profile and female thread design profile in a threading;
FIG. 4 is a schematic view of a conventional external thread having a flank angle 30 less than the flank angle α of the internal thread of the embodiment;
FIG. 5 is a schematic diagram of internal normal external thread pitch error compensation in threading;
FIG. 6 is a force analysis diagram of the internal thread as it is threaded with a conventional external thread;
FIG. 7 is a schematic diagram showing the stress distribution of each thread after the pitch error correction, wherein the crest points are contacted with the root arc.
Detailed Description
Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that: the relative arrangement of the components and steps, numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present invention unless it is specifically stated otherwise.
The following description of at least one exemplary embodiment is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses.
Techniques, methods, and apparatus known to one of ordinary skill in the relevant art may not be discussed in detail, but are intended to be part of the specification where appropriate.
In all examples shown and discussed herein, any specific values should be construed as merely illustrative, and not a limitation. Thus, other examples of exemplary embodiments may have different values.
It should be noted that: like reference numerals and letters denote like items in the following figures, and thus once an item is defined in one figure, no further discussion thereof is necessary in subsequent figures.
As shown in fig. 1 to 7, an axial positioning structure of a rotary machine part in an embodiment of the present application includes a shaft and a nut, wherein a common external thread is provided on the shaft, an internal thread is provided on an inner side of the nut, the nut is connected with a positioning portion of the shaft, and only a common external thread is provided on the positioning portion; the thread root of the internal thread design thread is arc-shaped and tangent to two sides of the thread groove of the internal thread, and the arc of the thread root of the internal thread is in contact screwing with the intersection line of two spirals of the common external thread.
In the embodiment, common external threads are adopted as standard parts, and a longitudinal groove on the shaft is eliminated; the novel internal thread design tooth form adopts a pitch compensation principle, so that under the conditions of axial positioning and locking and looseness prevention, the structure of two nuts or a round nut and a looseness prevention gasket or a nut and a flange is changed into a simple structure which is accurate in positioning, reliable in locking and looseness prevention and convenient to detach and maintain.
Aiming at the problem of uneven distribution of threaded connection load, in order to ensure that the loading of each thread tooth buckle is basically even under the effective screwing length, the defects of large loading of three buckles before common threads, easy plastic deformation of the thread tooth buckle and the like are overcome, and the bearing capacity of each thread tooth buckle is fully exerted. Therefore, under the condition of ensuring that the pitch of the internal common external thread is unchanged, the thread bottom of the internal thread is corrected, and the arc radius is tangent to the two sides of the thread bottom of the thread of the internal thread to form the design thread shape of the internal thread, so that two corresponding spiral lines on the arc of the thread bottom of the internal thread are respectively contacted with intersecting lines (namely two thread tips) on the two sides of the thread top of the common external thread, the arc of the thread bottom of the internal thread is of a variable wedge structure and has pitch error compensation and is in a regular change of reverse gradual widening along the thread axis, the sequence of entering the internal common external thread into the work bearing is changed, and the internal thread enters the bearing in reverse sequence, thereby realizing the purposes that each thread buckle of a thread pair is uniformly loaded, and the normal force is at least more than 2.4 times of the axial force of the thread.
A model diagram of the screwing structure of the standard common external thread and the internal thread of the embodiment is shown in fig. 1. Crest spiral line section part of common external threadDirectly with the internal thread root helical line segment portion/>, in this embodimentAll the threads are contacted in the screwing process, so that the internal common external thread screwing locking is realized.
The common external thread is assumed to be manufactured, the common external thread is required to be matched with the internal thread, and screwing, self-locking and anti-loosening are ensured, so that the common external thread is used as a standard reference, and the thread profile of the content of the invention is designed.
The internal thread is formed by enlarging the pitch diameter of the thread on the basis of the common thread to realize the width of the root of the common external threadEnlarged to line segment/>And/> (K is a coefficient, k > 1). Line segment/>The presence of (c) provides conditions for the implementation of the internal thread related parameters of the present invention.
The pitch diameter of the internal thread is separated from the pitch diameter of the common external thread, the separation distance of the two pitch diameters is h 1, D 2＝d2+2×h1(D2 is the virtual pitch diameter of the internal thread, D 2 is the pitch diameter of the common external thread, h 1 is the separation distance of the virtual pitch diameter of the internal thread and the pitch diameter of the common external thread, and h 1 is related to the pitch diameter P of the thread. ).
The common screw pair screwing is in contact with the tooth side in a matching way. The flank contact height describes the radial height of the flank overlap on the profile of two coaxially mating threads.
In this embodiment, because there is a separation distance h 1, a position offset h 2 also appears between an intersection point G of the original triangle of the common external thread and an intersection point F of the original triangle of the internal thread of the present invention, the thread is a thread segment of the thread root of the internal threadThe implementation of the coefficient k provides the possibility.
To ensure the thread-root helical line section of the internal threadCrest helical line segment/>, with common external threadsThe common external thread is in matched contact with the internal thread of the invention, and the flank angle alpha is increased. The flank angle in this example is 35 DEG > alpha > 30 DEG, and the profile angle is 70 DEG > 2 alpha > 60 deg.
The plane vertical to the axis of the internal thread is ensured to be coincident with the plane vertical to the axis of the common external thread through the related technology, the accumulated error of the thread pitch is reduced, the screwing quality of the thread pair is further ensured, and the self-locking performance and the anti-loosening performance of the thread pair are kept in the optimal state.
In order to further improve the assembly and disassembly performance, the structural model in fig. 1 needs to be further optimized, as shown in fig. 2.
In the basic profile of the normal external thread in the threading of fig. 2 and the basic profile of the internal thread of the present invention, the basic profile of a specific thread pair and its parameters are given.
In the figure, the basic profile of the common external thread completely meets the design requirement of GB/T192-2003 common thread basic profile, and related parameters thereof meet the requirements of GB/T193-2003 common thread diameter and pitch series, GB/T196-2003 common thread basic size, GB/T197-2018 common thread tolerance, GB/T2516-2003 common thread limit deviation, GB/T9144-2003 common thread preferred series, GB/T9145-2003 common thread medium precision, preferred series limit size and GB/T15756-2008 common thread limit size.
For this reason, the basic profile of the normal external thread is the standard reference basic profile of the present embodiment.
The normal external thread is a standard reference thread, and in order to optimize the relevant parameters in fig. 1, the basic tooth form design parameters of the thread pair shown in fig. 2 are further improved on the basis of fig. 1.
1. The common external thread involves the following parameters: the original triangle height H, the flank angle 30 degrees, the tooth angle 60 degrees, the crest flat height H/8, the root flat height H/4, the crest width P/8, the root width P/4, the crest height 3H/8, the tooth height 5H/8, the thread pitch diameter line and the thread axis are parallel and are positioned at the generatrix of the pitch diameter cylinder at half the original triangle height.
In the conventional cylindrical thread pair mating, it is required that contact interference cannot occur at the crests and roots thereof.
2. The internal thread of the invention relates to the following parameters: the original triangle height H 1, flank angle alpha, tooth angle 2 alpha, crest flat height H 4, root flat height H/8+h 2, root width b 1, crest width b, root height 3H/8-H 1, tooth height 5H/8, internal thread virtual pitch line and thread axis are parallel and located at the H/2 position of the original triangle from the F point height.
As can be seen from the expression of the parameters related to the internal thread, the internal thread is different from the common internal thread in the following table:
the invention provides a list of differences between the internal thread and the common external thread and common internal thread
In fig. 2, it is assumed that h 1、h2 has been established by the relevant design parameters in fig. 1, and that the pitch diameter of the ordinary male thread is distributed between the thread axis and the pitch diameter (virtual pitch diameter) of the female thread of the present invention. The vertex G of the original equilateral triangle of the common external thread is positioned at the crest of the regular equilateral triangleAnd the vertex F of the original isosceles triangle of the internal thread.
To optimize it even further, the basic profile of the thread is entered into the design profile of the thread, as shown in fig. 3.
In the general male thread design profile and the female thread design profile of the present invention in the threading of fig. 3, further description will be made with respect to the content of fig. 2.
In fig. 2, it is assumed that h 1、h2 has been established by the relevant design parameters in fig. 1, and that the pitch diameter of the ordinary male thread is distributed between the thread axis and the pitch diameter (virtual pitch diameter) of the female thread of the present invention. The vertex G of the original equilateral triangle of the common external thread is positioned at the crest of the regular equilateral triangleAnd the vertex F of the original isosceles triangle of the internal thread.
h1＝0.045P0.4d0.1-Δ
P: the pitch of the thread.
D: the geometric average value of two limit values of the basic large-diameter section of the corresponding thread of the common external thread pitch tolerance is obtained.
Delta: the correction amount is a function of the pitch P, delta=delta×p.
The delta-correction is a coefficient related to the pitch, 0 < delta < 1.
h2＝τ×h1
The tau-coefficient, depending on the size of R, is 2 > tau.gtoreq.1.
R-root arc radius of the internal thread of this embodiment.
R is the radius of an arc tangent to the two sides of the internal thread tooth groove of the invention through the intersection points (B, D) of the two sides of the common external thread basic tooth body and the H/8 flattening position line.
R＝Rmin～Rmax
R min -minimum arc radius of the internal thread root of the present invention, R min = 0.15011P (mm).
R max -maximum radius of arc of the root of the internal thread of the invention, R max = 0.18042P (mm).
The flank angle alpha (30 degrees < alpha < 35 degrees) of the internal thread of the embodiment is larger than the flank angle 30 degrees of the common external thread, namely, the flank angle 60 degrees < 2 alpha < 70 degrees of the invention is larger than the flank angle 60 degrees of the common external thread.
The internal thread of this embodiment should be designed according to the flank angle α (flank angle 2α), the designed thread height, the arc radius of the root, h1, h2, and the pitch of the normal thread; thereby ensuring that the pitch error of the pitch of each tooth socket accords with delta P＝0.007P0.4d0.1(ΔP -pitch deviation).
Because the internal thread and the common external thread form the thread pair, the arc radius R of the root of the internal thread and the spiral lines (B, D) on the two sides of the crest of the common external thread are respectively screwed together, wherein the D spiral line bears the main axial force of the common external thread, and the B spiral line overcomes the elastic deformation of the common external thread along the axial direction caused by the stress of the D spiral line; meanwhile, because the root arc radius R of the internal thread is corrected by the pitch deviation delta P caused by mechanical processing in the design and manufacture, the axial force born by the D spiral line of the main common external thread in the screwing process of the thread pair is uniform, and the B spiral line is effective in overcoming the elastic deformation of the common external thread along the axial direction caused by the stress of the D spiral line, so that the thread pair is provided with the thread pairCompared with the common screw thread, the screw thread is improved by more than 1.4 times.
By using the above data, the angle θ is calculated to be in the range of 65.4 ° to 69.7 °, where the normal force F Dn is 2.4 to 2.9 times the axial force F D. Compared with common screw thread screwing, the normal force stress ratio is (14.6-17.6): 7. the radial load of the arc thread at the thread root of the embodiment is far greater than the axial load, so that the generated friction force is greatly increased, and a higher anti-loosening effect is achieved.
The internal thread with the arc tooth bottom has the advantages that due to the special deformation inclined wedge structure, after the influence of the pitch error is comprehensively considered, the bearing capacity is relatively even on each tooth, so that the problems that the teeth of the common thread head are easy to generate plastic deformation and slide are solved. The internal thread with the arc tooth bottom realizes the anti-loosening effect due to the special deformed wedge structure.
Another greatest advantage of the internal thread of this embodiment is that the use of a variable wedge rounded root reduces stress concentrations and increases dynamic loading substantially.
The actual profile of the internal thread of this embodiment is composed of continuous smooth circular arc curves cut on both sides of the tooth socket, and the radius of the circular arc curves is not smaller than 0.15011P. In the common screw thread, the radius of the arc of the thread root of the screw thread is not smaller than 0.125P for the screw bolt with the level of 8.8 or more, which is obviously much smaller than that of the internal screw thread of the embodiment. This is the most significant reason why the fatigue life of the internal thread of this embodiment is higher than that of the normal thread.
When the internal thread of the embodiment is screwed up, the crest spiral line on one side of the common external thread tooth body is contacted with the arc D point of the root of the internal thread and locked by virtue of radial load, and the crest spiral line on the other side of the common external thread tooth body is contacted with the arc B point of the root of the internal thread of the embodiment to overcome the deformation of the common external thread, so that the internal thread fastener of the embodiment can be repeatedly disassembled and assembled without losing the locking force of the fastener under the condition of no axial load. The internally threaded locking threaded fastener of this embodiment is unscrewed and re-tightened up to 50 times without significant loss of locking force.
These all benefit from the fact that the internal thread design profile, and in particular the root arc, is consistent with the pitch error variation.
As shown in the schematic diagram of the stress distribution of each thread after the pitch error correction, the fatigue strength of the internal thread of this embodiment is 4 times higher than that of the normal thread after the pitch error correction, as shown in fig. 7, the two points of the crest (i.e., the two crests of the crest) are in contact with the arc of the root. Meanwhile, simulation data show that the normal stress of each tooth buckle of the screw thread pair is basically uniform, the normal stress is from 22% of the first buckle to 19% of the last buckle, the stress of each tooth buckle is basically uniform and has corresponding flexibility, and the phenomenon of uneven load distribution of the common screw thread pair is overcome.
The bearing axial positioning self-locking principle is formed by the internal thread and the common external thread in the embodiment:
Under the condition of no load, a gap exists between the bolt and the internal thread; if the bolt reaches a certain torque, the sharp point of the common external thread is tightly wedged on the spiral surface of the arc of the root of the internal thread, and the large diameter of the thread is contacted, so that the bolt cannot move laterally.
The contact surface of the common bolt and the internal thread of the embodiment has very high surface compressive stress, and the friction force after screwing the thread pair is increased.
The internal thread of the embodiment shows that the load is uniformly distributed on the whole meshing length, and the virtual pitch of the internal thread design teeth is in a reverse gradual widening change rule along the axis, so that the born load is borne and transmitted through two points of the contact of the circular arcs of the internal thread and the common external thread and the crests.
In a specific example of the present application, taking the m24×2 internal thread as an example, the relevant parameters of the design tooth form are:
Structural parameter list of the internal thread and the common external thread and the common internal thread of the embodiment
Take M24X 2-8.8 grade threads as an example
After the common external thread (standard thread) is screwed with the internal thread of the invention, the normal component force of each buckle is more than 1.4 times than that of the common thread pair, the friction force is increased, and the anti-vibration and anti-loosening capabilities are enhanced; the bearing load of each tooth buckle is uniform (the fluctuation range of the load is kept within +/-1.5 percent), the plastic deformation capacity of the tooth is enhanced, the service life of a screw thread pair is prolonged, and the relevant parameters and the anti-loosening performance of the nut pair are basically unchanged when the nut pair is continuously assembled and disassembled 50 through simulation data analysis; after the anti-loosening vibration performance test, if a single nut is adopted to axially position the bearing, the residual axial force/initial axial force is greater than 96%.
Turning the common internal thread is the basis of processing and is also the processing means of the internal thread. The tooth form is designed by taking the major diameter D, the minor diameter D 2 Hair brush , the tooth form angle 2 alpha, the tooth form pitch P and the like as basic parameters, taking Z-direction feed of a numerical control lathe as uniform acceleration movement, rotating a workpiece by one rotation tool to feed the workpiece by p+delta (delta is the axial feed increment of the tool after rotating the workpiece by one rotation), increasing the tooth form pitch to p+delta at the moment, returning the tool to a turning starting point (the same execution process is also the next tooth form pitch), and ensuring the tooth form pitch requirement of an internal thread tooth form.
In another specific embodiment of the present application, M16×1.5-6H female threads are used to threadingly engage conventional male threads M16×1.5-6H.
Wherein the original triangle of the thread of the M16 multiplied by 1.5-6H internal thread is an isosceles triangle, the design tooth shape is formed by 15.85mm of large diameter size, 15.17mm of medium diameter (virtual medium diameter) size, 14.38mm of small diameter size, 61 DEG 19 '25' of tooth shape angle and 0.23-0.29 mm of radius of the fillet of the root of the variable wedge, the effective screwing number of the thread is 7, and medium carbon steel quenching and tempering treatment (35-39 HRC) is adopted; compared with common screw thread screwing, the normal force stress ratio is 16.6:7, in the embodiment, the radial load of the arc thread at the thread root is far greater than the axial load, the friction force is also greatly increased, and a higher anti-loosening effect is achieved; the arc tooth bottoms of the inclined wedges are changed, so that stress concentration is reduced, and dynamic load is greatly improved; the locking force is not obviously lost after the screw is continuously unscrewed and re-screwed for 50 times; the fatigue strength is 4 times higher than that of common threads; the normal stress of each tooth buckle of the screw thread pair is basically uniform, the normal stress is from 22% of the first buckle to 19% of the last buckle, and each tooth buckle is basically uniform in stress and has corresponding flexibility, so that the phenomenon of uneven load distribution of the common screw thread pair is overcome. When a single nut is used to axially position the bearing, the residual axial force/initial axial force is greater than 97.2%.
According to a second aspect of the present application, there is provided a rotary machine employing the axial positioning structure of the above-described rotary machine component.
According to one embodiment of the present disclosure, the axial positioning structure is adopted, starting from the reason of the uneven load distribution of the threaded connection, ensuring that the loading of each thread tooth buckle is basically uniform under the effective screwing length, overcoming the defects of large loading of three buckles before the common thread, easy plastic deformation of the thread tooth buckle, and the like, and fully playing the bearing capacity of each thread tooth buckle.
Under the condition of ensuring that the pitch of the internal common external thread is unchanged, the thread bottoms of the internal thread are corrected, and the arc radius is tangent to the two sides of the thread bottoms of the thread grooves of the internal thread to form the designed thread shape of the internal thread, so that two corresponding spiral lines on the arc of the thread bottoms of the internal thread are respectively contacted with intersecting lines (namely two thread tips) on the two sides of the thread tops of the common external thread, the arc of the thread bottoms of the internal thread is of a variable-pitch wedge structure and has pitch error compensation and is in regular change of reverse gradual widening along the thread axis, the sequence of entering the internal common external thread into the work bearing is changed, and the reverse sequence of entering the internal thread into the bearing is realized, thereby realizing the purposes that each thread buckle of a thread pair is uniformly loaded, and the normal force is at least 1.4 times of the axial force of the thread.
While certain specific embodiments of the invention have been described in detail by way of example, it will be appreciated by those skilled in the art that the above examples are for illustration only and are not intended to limit the scope of the invention. It will be appreciated by those skilled in the art that modifications may be made to the above embodiments without departing from the scope and spirit of the invention. The scope of the invention is defined by the appended claims.
Claims (3)
1. The axial positioning structure of the rotary mechanical part comprises a shaft and a nut, wherein the shaft is provided with common external threads, and the inner side of the nut is provided with internal threads; the thread root of the internal thread design thread is arc-shaped and tangent to two sides of a thread groove of the internal thread, the thread root arc of the internal thread is in contact screwing with the intersecting line of two threads of the common external thread, and the thread root arc of the internal thread is of a variable-pitch wedge structure, has pitch error compensation and changes along the thread axis in a reverse gradual widening rule; the virtual pitch line of the internal thread is separated from the pitch line of the common external thread, so that the following formula is realized:
D2＝d2+2×h1；
Wherein D 2 is the virtual pitch diameter of the internal thread, D 2 is the pitch diameter of the common external thread, and h 1 is the separation distance between the virtual pitch diameter of the internal thread and the pitch diameter of the common external thread;
The flank angle of the internal thread is as follows: 35 DEG > alpha > 30 DEG, and the profile angle of the internal thread is 70 DEG > 2 alpha > 60 deg.
2. The axial positioning structure of a rotary machine part according to claim 1, wherein the profile of the internal thread is composed of a continuous circular arc curve tangential to both sides of the socket, the radius of the circular arc curve being not less than 0.15011P and not more than 0.18042P.
3.A rotary machine characterized in that the axial positioning structure of the rotary machine part according to claim 1 or 2 is employed.
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| CN202311480221.9A CN117329239B (en) | 2023-11-08 | 2023-11-08 | Axial positioning structure of rotary mechanical part |
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| CN202311480221.9A CN117329239B (en) | 2023-11-08 | 2023-11-08 | Axial positioning structure of rotary mechanical part |
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2911288Y (en) * | 2006-05-24 | 2007-06-13 | 上海斯巴洛克精密紧固件有限公司 | Self-locking loosen-proof and anti-drop nut |
| CN112576594A (en) * | 2020-12-07 | 2021-03-30 | 泰尔重工股份有限公司 | Large-root fillet uniform-strength thread and machining method thereof |
| CN214788513U (en) * | 2021-05-07 | 2021-11-19 | 苏州誉高紧固系统有限公司 | Thread locking structure with arc R-shaped tooth bottoms |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3523162A1 (en) * | 1984-07-12 | 1986-01-23 | Zahnradfabrik Friedrichshafen Ag, 7990 Friedrichshafen | Steering lock limiter |
| CN201407270Y (en) * | 2009-05-21 | 2010-02-17 | 上海底特精密紧固件有限公司 | Anti-loosing inner thread part |
| CN208870546U (en) * | 2018-08-02 | 2019-05-17 | 上海海隆石油管材研究所 | A kind of deep-well and extended reach well tubing string helicitic texture |
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2023
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Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2911288Y (en) * | 2006-05-24 | 2007-06-13 | 上海斯巴洛克精密紧固件有限公司 | Self-locking loosen-proof and anti-drop nut |
| CN112576594A (en) * | 2020-12-07 | 2021-03-30 | 泰尔重工股份有限公司 | Large-root fillet uniform-strength thread and machining method thereof |
| CN214788513U (en) * | 2021-05-07 | 2021-11-19 | 苏州誉高紧固系统有限公司 | Thread locking structure with arc R-shaped tooth bottoms |
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