CN113757324A - Roller design method for easy-to-machine small-pitch planetary roller screw pair and roller - Google Patents

Roller design method for easy-to-machine small-pitch planetary roller screw pair and roller Download PDF

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CN113757324A
CN113757324A CN202110953190.9A CN202110953190A CN113757324A CN 113757324 A CN113757324 A CN 113757324A CN 202110953190 A CN202110953190 A CN 202110953190A CN 113757324 A CN113757324 A CN 113757324A
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roller
thread
gear
threads
tooth
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CN113757324B (en
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霍希建
张新华
黄建
段小帅
关平
郑欢
周围
赵帆
李晓斌
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Beijing Automation Control Equipment Institute BACEI
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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
    • F16H—GEARING
    • F16H25/00—Gearings comprising primarily only cams, cam-followers and screw-and-nut mechanisms
    • F16H25/18—Gearings comprising primarily only cams, cam-followers and screw-and-nut mechanisms for conveying or interconverting oscillating or reciprocating motions
    • F16H25/20—Screw mechanisms
    • F16H25/22—Screw mechanisms with balls, rollers, or similar members between the co-operating parts; Elements essential to the use of such members
    • F16H25/2247—Screw mechanisms with balls, rollers, or similar members between the co-operating parts; Elements essential to the use of such members with rollers
    • F16H25/2252—Planetary rollers between nut and screw
    • 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
    • F16H—GEARING
    • F16H57/00—General details of gearing
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F30/00—Computer-aided design [CAD]
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    • G06F30/17—Mechanical parametric or variational design
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F30/00—Computer-aided design [CAD]
    • G06F30/20—Design optimisation, verification or simulation
    • G06F30/23—Design optimisation, verification or simulation using finite element methods [FEM] or finite difference methods [FDM]
    • 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
    • F16H—GEARING
    • F16H57/00—General details of gearing
    • F16H2057/0087—Computer aided design [CAD] specially adapted for gearing features ; Analysis of gear systems
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T90/00—Enabling technologies or technologies with a potential or indirect contribution to GHG emissions mitigation

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Abstract

The invention provides a roller design method and a roller of an easy-to-machine small-pitch planetary roller screw pair, wherein the design method comprises the steps of designing a roller thread profile; the roller threads of the tooth form are designed in the whole section area of the roller; designing gears at two ends of the roller to enable the diameter of the addendum circle to be equal to the major diameter of the roller thread; and (3) performing intermediate diameter modification on the roller threads in the gear areas, and keeping the thread profile of the roller threads unchanged, so that when the planetary roller screw pair is subjected to an axial rated dynamic load, the roller threads in the gear areas on two sides are in contact with the external threads of the screw or the internal threads of the nut. The design method improves the bearing capacity and service life of the roller, reduces the processing difficulty, ensures the processing feasibility, is suitable for planetary roller screw pairs with different tooth form angles, is particularly suitable for improving the bearing capacity and service life of the small-pitch planetary roller screw pair, and solves the problems of unreasonable contact state of the existing roller threads, low bearing capacity, difficult processing after thread trimming and the like.

Description

Roller design method for easy-to-machine small-pitch planetary roller screw pair and roller
Technical Field
The invention belongs to the technical field of planetary roller screw pairs, and particularly relates to a roller design method and a roller of a high-bearing easy-to-machine small-pitch planetary roller screw pair.
Background
The planetary roller screw pair is a precise mechanical transmission mechanism and can realize the conversion between rotary motion and linear motion. The small-pitch planetary roller screw pair (the pitch P is less than or equal to 0.5mm) becomes a core functional component of a new generation aerospace servo system due to the advantages of large reduction ratio, high transmission precision and the like.
The planetary roller screw pair mainly comprises a screw, a nut, a roller, a gear ring, a retainer and other parts. The roller is provided with a single-line external thread, and gears are processed at two ends of the roller. The plurality of rollers are uniformly distributed around the circumference of the screw rod, the roller threads are respectively in threaded engagement with the external threads of the screw rod and the internal threads of the nut, and the roller gear is in gear engagement with the gear ring, as shown in fig. 1. At present, the external thread of the screw rod and the internal thread of the nut mostly adopt the linear flank thread with the flank angle of 45 degrees, and the roller thread adopts the arc flank thread matched with the roller thread so as to improve the bearing capacity and the transmission efficiency. However, a thread with a flank angle of 45 ° has its limitations, and particularly for a planetary roller screw pair with a small pitch, the impact resistance of the thread is low, which requires a reasonable flank angle to be selected. At present, no perfect method exists for designing the parameters of the roller thread profile with different flank angles.
The roller is used as a core part of the planetary roller screw pair and plays an important role in motion transmission and bearing. By changing the tooth flank shape and the roller structure of the roller thread, the bearing performance and the transmission efficiency of the planetary roller screw pair can be improved. Currently, there are two typical forms of roller structures: the first is a 'thread-gear independent design' form, namely, the gear areas at two ends of the roller have no threads, the roller gear is only meshed with the gear ring, and the thread processing and the gear processing areas are independent, so that the structure has better processability, and has the defects that the addendum circle is smaller than the middle diameter of the roller, the contact ratio of gear transmission is lower, the thread areas participating in the meshing transmission are reduced, the bearing capacity of the planetary roller screw pair is seriously reduced, and the structure is particularly not suitable for the small-pitch planetary roller screw pair, as shown in fig. 2; the second type is a form of a 'thread-gear hybrid design', namely, the gears at two ends of the roller are also provided with threads, the threads of the gear areas at two ends of the roller are in thread engagement with the screw rod and the nut, and the gears at two ends and the gear ring are in gear transmission.
Aiming at the second structural form, the tooth sockets at the two ends of the roller destroy the integrity of the threads, and when the planetary roller screw pair transmits load, the stress of the roller is mainly concentrated on a plurality of threads at the end part, so that the discontinuous thread teeth on the gears at the two ends generate overlarge deformation to cause the failure and the damage of the threads, and the transmission performance and the service life of the planetary roller screw pair are reduced. In order to solve the problem, Chinese patent CN201710343295.6 carries out 'qualitative' modification on the thread of the roller gear area, and three different thread pitch diameters are adopted, and the pitch diameter value is continuously changed. The chinese patent cn201611091503.x performs 'quantitative' modification on the tooth thickness of two sides of the roller thread respectively, and requires that the cutter feeding speed is processed according to a linearization rule. Because the geometric accuracy requirement of the small-pitch thread is high (not less than 2 mu m) and the thread height is small, the current processing equipment is difficult to meet the processing requirement of changing the pitch diameter or the tooth profile. Therefore, no roller design method suitable for the small-pitch planetary roller screw pair exists at present from the aspects of improving the bearing capacity and the processing realizability.
Disclosure of Invention
The invention aims to provide a roller design method of a high-bearing easy-to-machine small-pitch planetary roller screw pair and a roller, which are used for solving the problems of unreasonable contact state of the threads of the conventional roller, low bearing capacity, difficulty in machining after thread modification and the like, improving the bearing capacity and service life of the roller, reducing the machining difficulty, ensuring the machining feasibility, and are suitable for planetary roller screw pairs with different thread angles, in particular for improving the bearing capacity and service life of the small-pitch planetary roller screw pair.
The technical scheme adopted by the invention for solving the technical problems is as follows:
the invention provides a roller design method of an easy-to-machine small-pitch planetary roller screw pair, which comprises the following steps
Designing a roller thread profile;
the roller threads of the tooth form are designed in the whole section area of the roller;
designing gears at two ends of the roller, wherein the diameter of the top circle of the gear is equal to the major diameter of the thread of the roller;
and (3) performing intermediate diameter modification on the roller threads in the gear areas, and keeping the thread profile of the roller threads unchanged, so that when the planetary roller screw pair is subjected to an axial rated dynamic load, the roller threads in the gear areas on two sides are in contact with the external threads of the screw or the internal threads of the nut.
Further, the roller thread profile is a circular arc flank.
Further, the design method of the roller thread profile of the circular arc flank is as follows
S1.1, designing the flank angle to be alpharThe three adjacent thread original triangles are marked as a first thread tooth, a second thread tooth and a third thread tooth, tangent circles of a right tooth side of the first thread tooth, a left tooth side of the second thread tooth and a left tooth side of the third thread tooth are respectively made, the circle centers of the tangent circles are positioned on the axis of the roller, and the tangent point is the intersection point of the tooth side and the pitch diameter line of the thread;
s1.2, making undercut circles at the bottoms of tooth sockets among the three threads, wherein the undercut circles are tangent to tangent circles of two adjacent teeth in the step S1.1 at the same time;
s1.3, drawing a large radial line of the roller thread, and selecting a left circular arc, a right circular arc, a root circular arc and a crest on a left thread side tangent circle, a right thread side tangent circle, two root tangent circles and a large meridian line of a second thread tooth respectively to form a continuous thread profile.
Further, the flank angle αrThe range is 30-45 degrees.
Furthermore, the gear is processed by an involute straight toothed cylindrical gear and a hobbing method.
Further, the pitch diameter modification amount of the thread in the gear area is
Figure BDA0003219312040000041
The gear area has a thread pitch diameter value of
Figure BDA0003219312040000042
Wherein d isrFor the mean diameter value of the roller thread before dressing, drMThe thread pitch diameter value of the gear areas on two sides; delta is the deformation of the thread teeth of the roller when the planetary roller screw pair reaches the specified axial rated dynamic load and only the thread length of the middle area participates in the meshing;
Figure BDA0003219312040000043
flank angle of alphar。
The invention also provides a roller of the planetary roller screw pair with easy processing and small pitch, which comprises a first gear, a middle section and a second gear which are sequentially communicated, wherein the first gear, the middle section and the second gear respectively comprise single-line external threads, the profiles of the external thread profiles are the same, the middle diameter of the threads on the first gear and the second gear are modified, and after modification, when the planetary roller screw pair is subjected to axial rated dynamic load, the roller threads in the gear areas at two sides are in contact with the external threads of the screw or the internal threads of the nut.
Furthermore, the external thread profile is a circular arc profile, and the gear is an involute straight toothed spur gear.
Compared with the prior art, the invention has the beneficial effects that:
the invention provides a roller design method of a high-bearing easy-processing small-pitch planetary roller screw pair, which has the advantages that: 1) the design method is suitable for the roller thread design of the planetary roller screw pair with different flank angles, and has strong universality; 2) the form of 'thread-gear mixed design' is adopted, the length of the meshing thread is increased, and the contact ratio and the transmission stability of the roller gear-gear ring are improved; 3) by adopting the three-section type thread pitch diameter modification, the uniform load distribution state of the load in the roller thread area is improved, the maximum load borne by discontinuous thread teeth in the gear area is reduced, the limit bearing capacity of the planetary roller screw pair is improved, and the axial load is improved by more than 40% compared with that before modification; 4) the thread pitch diameter values of the gear areas at the two ends and the middle area between the two gears of the roller are fixed values after the profile modification, the tooth profiles are the same, thread machining can be carried out by adopting a forming thread cutter with one specification, the machining difficulty is greatly reduced, and the manufacturing problem of the small-pitch planetary roller screw pair is solved.
Drawings
The accompanying drawings, which are included to provide a further understanding of the embodiments of the invention and 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. It is obvious that the drawings in the following description are only some embodiments of the invention, and that for a person skilled in the art, other drawings can be derived from them without inventive effort.
FIG. 1 is a block diagram of a planetary roller screw set;
FIG. 2 is a first roller configuration;
FIG. 3 is a second roller configuration;
FIG. 4 is a diagram of a roller thread profile provided by an embodiment of the present invention;
FIG. 5 is a basic thread form of a roller thread provided by an embodiment of the present invention;
FIG. 6 is a roller thread profile layout provided by an exemplary embodiment of the present invention;
FIG. 7 is a sectional view of a roller thread pitch radius profile according to an embodiment of the present invention;
FIG. 8 is a schematic diagram of a roller thread pitch diameter profile relationship provided by an embodiment of the present invention.
Wherein the figures include the following reference numerals:
1. the thread comprises a screw rod, 2 rollers, 3 nuts, 4 gear rings, 5 retainers, 6 gears, 7 roller threads, 7-1 left flank, 7-2 right flanks, 7-3 root arcs, 7-4 crests, 7-5 thread pitch lines, 8 cylindrical shafts, 9 roller axes, 10 external thread original triangles, 10-1 original triangle left flanks, 10-2 original triangle right flanks, 11 second threads, 11-1 second thread left flank vertical lines, 11-2 second thread left flank tangent circles, 11-3 second thread right flank vertical lines, 11-4 second thread right flank tangent circles, 12 first threads, 12-1 first thread right flank vertical lines, 12-2 first thread right flank tangent circles, 7-1 first thread right flank tangent circles, and 7-1 roller threads, 13. 13-1 parts of a third thread, 13-2 parts of a left thread side vertical line of the third thread, 13-2 parts of a left thread side tangent circle of the third thread, 14 parts of a thread large diameter line, 15 parts of a thread undercut circle, 16 parts of a gear area thread middle diameter line, 17 parts of a middle area and 18 parts of two side gear areas.
Detailed Description
The following provides a detailed description of specific embodiments of the present invention. In the following description, for purposes of explanation and not limitation, specific details are set forth in order to provide a thorough understanding of the present invention. However, it will be apparent to one skilled in the art that the present invention may be practiced in other embodiments that depart from these specific details.
It should be noted that, in order to avoid obscuring the present invention with unnecessary details, only the device structures and/or processing steps closely related to the scheme of the present invention are shown in the drawings, and other details not so related to the present invention are omitted.
The invention provides a roller design method of a high-bearing easy-to-process small-pitch planetary roller screw pair, which comprises a thread profile design, a gear design and a thread pitch diameter modification, wherein the roller adopts an external thread based on a circular arc flank to realize efficient meshing with a screw rod and a nut, simultaneously, two ends of the roller adopt involute straight tooth cylindrical gears, and in addition, the overall thread pitch diameter design of the roller adopts a three-section modification mode.
The invention provides a roller design method of an easy-to-machine small-pitch planetary roller screw pair, which comprises the following steps of:
and S1, designing a roller thread profile and adopting a circular arc flank.
Specifically, the design method of the arc-shaped tooth flank is as follows,
s1.1, designing the flank angle to be alpharThe three adjacent thread original triangles are marked as a first thread tooth, a second thread tooth and a third thread tooth, tangent circles of a right tooth side of the first thread tooth, a left tooth side of the second thread tooth and a left tooth side of the third thread tooth are respectively made, the circle centers of the tangent circles are positioned on the axis of the roller, and the tangent point is the intersection point of the tooth side and the pitch diameter line of the thread.
S1.2, making undercut circles at the bottoms of tooth sockets among the three threads, wherein the undercut circles are tangent to the tangent circles of the two adjacent teeth in the step S1.1 at the same time.
S1.3, drawing a large radial line of the roller thread, and selecting a left circular arc, a right circular arc, a root circular arc and a crest on a left thread side tangent circle, a right thread side tangent circle, two root tangent circles and a large meridian line of a second thread tooth respectively to form a continuous thread profile.
And S2, designing roller threads in the step S1 in all the roller section areas.
S3, designing gears at two ends of the roller, and adopting an involute straight tooth cylindrical gear, wherein the diameter of the addendum circle is equal to the major diameter of the roller thread.
And S4, performing intermediate modification on the roller threads in the gear areas, and keeping the thread profile of the roller threads unchanged, so that when the planetary roller screw pair is subjected to rated load, the roller threads in the gear areas on two sides are just in contact with the external threads of the screw or the internal threads of the nut.
The technical solution of the present invention is explained in detail with reference to a specific embodiment.
As shown in figure 3, the roller 2 of the planetary roller screw pair with the small thread pitch and easy to machine comprises a gear 6, a roller thread 7 and a cylindrical shaft 8, wherein the roller 2 adopts the roller thread 7 based on a circular arc flank, the roller thread covers the whole section area of the roller to realize efficient meshing with a screw rod and a nut, the two ends of the roller 2 adopt involute straight toothed cylindrical gears 6, and the thread pitch diameter design of the roller 2 adopts a three-section type modification mode. In the planetary roller screw pair, the roller threads 7 of the rollers 2 are meshed with the threads of the screw 1 and the nut 3, the gears 6 at two ends of the rollers 2 are in gear meshing with the gear ring 4, and the cylindrical shafts 8 at two ends of the rollers are matched with the holes on the retainer 5.
As shown in figures 4, 5 and 6, the rollers 2 of the small-pitch planetary roller screw pair are in a single-thread form, the thread flanks are arc-shaped, and the left flank 7-1 and the right flank 7-2 of the thread flanks are symmetrically distributed. The process of designing the profile of the roller thread is explained below from a theoretical point of view: drawing 3 flank angles as alpharComprises a first thread ridge 12, a second thread ridge 11 and a third thread ridge 13, and each thread ridge comprises an original triangular left flank 10-1 and an original triangular right flank 10-2. Respectively determining the intersection points of the left flank 10-1 and the right flank 10-2 of the original triangle and the pitch diameter line 7-5, respectively drawing the vertical lines of the left flank 10-1 and the right flank 10-2 through the intersection points to obtain the left flank vertical line 11-1 and the right flank vertical line 11-3 of the second thread 11, respectively taking the intersection point of the vertical line 11-1 and the roller axis 9 and the intersection point of the vertical line 11-3 and the roller axis 9 as the circle center, and respectively taking the intersection points of the vertical line 11-1 and the roller axis 9 as the circle centers
Figure BDA0003219312040000081
Circles are drawn for the radii to obtain a left flank tangent circle 11-2 and a right flank tangent circle 11-4 of the second thread ridge 11. In the formula (d)rThe pitch diameter of the roller thread 7, i.e. the thread pitch diameter value, alpharThe flank angle of the roller thread 7, preferably the low pitch flank angle αrThe range is 30-45 degrees.
Aiming at the first thread ridge 12, determining the intersection point of the original triangular right flank 10-2 and the thread pitch diameter line 7-5, drawing a perpendicular line of the first thread ridge right flank 10-2 through the intersection point to obtain a first thread ridge right flank perpendicular line 12-1, and taking the intersection point of the first thread ridge right flank perpendicular line 12-1 and the roller axis 9 as the center of a circle and taking the intersection point as the center of the circle
Figure BDA0003219312040000082
And drawing a circle for the radius to obtain a tangent circle 12-2 of the right flank of the first thread.
Aiming at the third thread ridge 13, determining the intersection point of the original triangular left flank 10-1 and the thread pitch diameter line 7-5, drawing a perpendicular line of the third thread ridge left flank 10-1 through the intersection point to obtain a third thread ridge left flank perpendicular line 13-1, and taking the intersection point of the third thread ridge left flank perpendicular line 13-1 and the roller axis 9 as the center of a circle and taking the intersection point as the center of the circle
Figure BDA0003219312040000091
And drawing a circle for the radius to obtain a left flank tangent circle 13-2 of the third thread.
The major diameter line 14 of the roller thread is drawn. Making a root tangent circle 15 with the radius of r at the bottom of the thread groove, and ensuring that the root tangent circle is simultaneously tangent with a left flank tangent circle 11-2 of the second thread and a right flank tangent circle 12-2 of the first thread; and a root tangent circle 15 with the radius of r is made at the bottom of the thread groove, and the root tangent circle is tangent to the right flank tangent circle 11-4 of the second thread and the left flank tangent circle 13-2 of the third thread simultaneously. The principle of r selection is to ensure that the tooth bottom height is greater than the tooth top height of the screw 1 and the nut 3 in the planetary roller screw pair. On the basis, on a left thread side tangent circle 11-2 of a second thread, a right thread side tangent circle 11-4 of the second thread and a root tangent circle 15, a left side arc 7-1, a right side arc 7-2 and a root arc 7-3 are selected, and simultaneously, the left side arc 7-1, the right side arc 7-2 and the root arc 7-3 and a crest 7-4 form a thread profile of the roller 2. Wherein the crest 7-4 is a part of the large meridian 14 between the left circular arc 7-1 and the right circular arc 7-2.
As shown in fig. 7 and 8, the roller threads 7 are designed in the whole section area of the roller, so that the effective length of the roller threads under large load is increased; the gears 6 at the two ends of the roller are involute straight tooth cylindrical gears, the diameter of the addendum circle is equal to the diameter of the thread of the roller, and the gears 6 adopt a hobbing method.
The method is designed by adopting a method of modifying the pitch diameter of the thread and keeping the profile of the thread unchanged. The pitch diameter of the thread of the roller 2 is divided into 3 sections in the whole length, wherein gear areas 18 on two sides are respectively arranged at two ends of the roller, the axial length is equal to the width of the gear 6, the area belongs to a 'gear-thread mixed structure', the bearing capacity of the thread is low, and the modification criterion is that when the planetary roller screw pair is subjected to axial rated dynamic load, the roller threads 7 in the gear areas 18 on two sides are just in contact with the external thread of the screw 1 or the internal thread of the nut 3. The pitch diameter of the roller threads in the intermediate region 17 remains constant. The calculation formula of the thread pitch diameter modification amount of the gear areas at two sides is
Figure BDA0003219312040000101
The pitch diameter of the threads of the two side gear regions 18 has a value of
Figure BDA0003219312040000102
In the formula (d)rThe value of the pitch diameter of the roller before dressing, i.e. the value of the pitch diameter of the thread in the intermediate zone 17, drMThe value of the thread pitch diameter of the gear areas 18 on both sides is delta, which is the deformation of the thread of the roller when the thread length of the middle section participates in the engagement when the planetary roller screw pair reaches the specified axial rated dynamic load. The deformation can be obtained by numerical calculation or finite element simulation, when the deformation is obtained, only the threads in the middle section participate in load loading analysis, and the gear areas at the two ends do not carry out load analysis.
The thread pitch diameter of the gear areas is reduced to reduce the thickness of the thread at the contact point, so that a certain amount of gaps are reserved between the thread flanks of the gear areas 18 on the two sides and the thread flanks of the screw rod 1 and the nut 3, the uniform load distribution state of the load in the roller thread areas is improved, the maximum load borne by the discontinuous thread flanks of the gear areas 18 on the two sides is reduced, the failure and damage of the threads due to overload are avoided, and the limit bearing capacity of the planetary roller screw pair is improved.
According to the roller of the small-pitch planetary roller screw pair based on the thread pitch diameter modification, threads can be turned only by adopting a forming arc thread cutter with one specification in thread machining, the thread machining efficiency can be effectively improved, particularly for small-pitch threads, the processability of the modified threads is good, and the dimensional precision better than that of thread grinding can be obtained.
Features that are described and/or illustrated above with respect to one embodiment may be used in the same way or in a similar way in one or more other embodiments and/or in combination with or instead of the features of the other embodiments.
It should be emphasized that the term "comprises/comprising" when used herein, is taken to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.
The many features and advantages of these embodiments are apparent from the detailed specification, and thus, it is intended by the appended claims to cover all such features and advantages of these embodiments which fall within the true spirit and scope thereof. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the embodiments of the invention to the exact construction and operation illustrated and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope thereof.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
The invention has not been described in detail and is in part known to those of skill in the art.

Claims (8)

1. The roller design method of the planetary roller screw pair with the small pitch and easy processing is characterized by comprising the following steps
Designing a roller thread profile;
the roller threads of the tooth form are designed in the whole section area of the roller;
designing gears at two ends of the roller, wherein the diameter of the top circle of the gear is equal to the major diameter of the thread of the roller;
and (3) performing intermediate diameter modification on the roller threads in the gear areas, and keeping the thread profile of the roller threads unchanged, so that when the planetary roller screw pair is subjected to an axial rated dynamic load, the roller threads in the gear areas on two sides are in contact with the external threads of the screw or the internal threads of the nut.
2. A roller design method as claimed in claim 1 wherein the roller thread profile is a rounded flank.
3. The roller design method of claim 2, wherein the roller thread profile of the circular arc flanks is designed as follows
S1.1, designing the flank angle to be alpharThe three adjacent thread original triangles are marked as a first thread tooth, a second thread tooth and a third thread tooth, tangent circles of a right tooth side of the first thread tooth, a left tooth side of the second thread tooth and a left tooth side of the third thread tooth are respectively made, the circle centers of the tangent circles are positioned on the axis of the roller, and the tangent point is the intersection point of the tooth side and the pitch diameter line of the thread;
s1.2, making undercut circles at the bottoms of tooth sockets among the three threads, wherein the undercut circles are tangent to tangent circles of two adjacent teeth in the step S1.1 at the same time;
s1.3, drawing a large radial line of the roller thread, and selecting a left circular arc, a right circular arc, a root circular arc and a crest on a left thread side tangent circle, a right thread side tangent circle, two root tangent circles and a large meridian line of a second thread tooth respectively to form a continuous thread profile.
4. A roller design method as claimed in claim 3 wherein the flank angle arThe range is 30-45 degrees.
5. A roller design method as claimed in claim 1 wherein the gears are involute spur gears and are machined by the hobbing method.
6. A roller design method as claimed in claim 1 wherein the gear region thread pitch is reduced by an amount of radius modification
Figure FDA0003219312030000021
The gear area has a thread pitch diameter value of
Figure FDA0003219312030000022
Wherein d isrFor the mean diameter value of the roller thread before dressing, drMThe thread pitch diameter value of the gear areas on two sides; delta is the deformation of the thread teeth of the roller when the planetary roller screw pair reaches the specified axial rated dynamic load and only the thread length of the middle area participates in the meshing;
Figure FDA0003219312030000023
flank angle of alphar。
7. The utility model provides an easy processing fine pitch planet roller screw pair's roller, its characterized in that, is including first gear, interlude, the second gear that communicates in proper order, all including single line external screw thread and external screw thread profile on first gear, interlude, the second gear the same, the radius is repaiied in the screw thread on first gear, the second gear, when planet roller screw pair received the rated dynamic load of axial after the repairment type, the internal thread contact of the external screw thread of roller screw and lead screw or nut in the gear area of both sides.
8. The roller as claimed in claim 7, wherein the external thread profile is a circular arc profile, and the gear is an involute spur gear.
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CN117588539A (en) * 2024-01-17 2024-02-23 杭州新剑机电传动股份有限公司 Planetary roller screw

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CN116989110A (en) * 2023-09-27 2023-11-03 江西炬龙精密科技有限公司 Uniform load planetary roller screw pair
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