CN113757324B - Roller design method and roller of easy-to-process small-pitch planetary roller screw pair - Google Patents
Roller design method and roller of easy-to-process small-pitch planetary roller screw pair Download PDFInfo
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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
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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
- F16H57/00—General details of gearing
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- G—PHYSICS
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- G06F—ELECTRIC DIGITAL DATA PROCESSING
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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
- F16H57/00—General details of gearing
- F16H2057/0087—Computer aided design [CAD] specially adapted for gearing features ; Analysis of gear systems
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Abstract
The invention provides a roller design method and a roller of an easy-to-process small-pitch planetary roller screw pair, wherein the design method comprises the steps of designing a roller thread profile; the tooth-shaped roller threads are designed in the roller full-segment areas; designing gears at two ends of the roller so that the diameter of the addendum circle is equal to the major diameter of the roller thread; and (3) performing pitch diameter modification on the roller threads in the gear areas, wherein the profile of the roller thread profile is kept unchanged, so that when the planetary roller screw pair receives an axial rated dynamic load, the roller threads in the gear areas at two sides are contacted with the external threads of the screw or the internal threads of the nuts. 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 angles, is particularly suitable for improving the bearing capacity and service life of the planetary roller screw pair with small pitch, and solves the problems of unreasonable contact state, low bearing capacity, difficult processing after thread repair and the like of the conventional roller threads.
Description
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 and easy-to-process 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 (pitch P is less than or equal to 0.5 mm) has the advantages of large reduction ratio, high transmission precision and the like, and becomes a core functional component of a new generation of aerospace servo system.
The planetary roller screw pair mainly comprises parts such as a screw, a nut, rollers, a gear ring, a retainer and the like. The roller has single line external screw thread, and the gear is processed at roller both ends. The 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 meanwhile, the roller gears are in gear engagement with the gear ring, as shown in figure 1. At present, most of external screw threads of a screw rod and internal screw threads of a nut adopt linear tooth side screw threads with a tooth side angle of 45 degrees, and roller screw threads adopt circular arc tooth side screw threads matched with the linear tooth side screw threads so as to improve bearing capacity and transmission efficiency. However, the thread with a flank angle of 45 ° has its limitations, especially for small pitch planetary roller screw pairs, 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 thread form parameters of the roller threads aiming at 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 side 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 in a thread-gear independent design mode, namely, the gear areas at the two ends of the roller are not provided with threads, the roller gear is meshed with the gear ring only, and the processing of the thread is independent of the processing area of the gear, so that the processing of the structure is better, the defect is that the gear transmission overlap ratio is lower because the addendum circle is smaller than the pitch diameter of the roller, the thread area participating in the meshing transmission is reduced, the bearing capacity of the planetary roller screw pair is seriously reduced, and the planetary roller screw pair is particularly not suitable for the planetary roller screw pair with small pitch, as shown in figure 2; the second type is a thread-gear mixed design, namely, the gears at the two ends of the roller are also provided with threads, the threads at the gear areas at the two ends of the roller are in threaded engagement with the screw rod and the nut, and meanwhile, the gears at the two ends are in gear transmission with the gear ring.
Aiming at the second structural form, tooth grooves at two ends of the roller destroy the integrity of threads, and as the planetary roller screw pair transmits load, the stress of the roller is mainly concentrated on a plurality of threads at the end parts, so that discontinuous thread teeth on gears at two ends generate excessive deformation to cause failure and damage of the threads, and the transmission performance and the service life of the planetary roller screw pair are reduced. To address this problem, chinese patent CN201710343295.6 "qualitative" modifications to the threads of the roller gear region, three different thread pitch diameters were employed and the pitch diameter values were continuously varied. The chinese patent cn20161091503. X performs "quantitative" modification of the thread thickness on both sides of the roller thread, respectively, and requires that the tool feed speed performs processing according to the 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 smaller, the current processing equipment is difficult to meet the processing requirement of changing pitch diameter or tooth shape. Therefore, there is no roller design method suitable for a small pitch planetary roller screw pair from the aspects of improving the bearing capacity and the processing availability.
Disclosure of Invention
The invention aims to provide a roller design method and a roller of a high-bearing and easy-to-process small-pitch planetary roller screw pair, which are used for solving the problems of unreasonable threaded contact state, low bearing capacity, difficult post-thread machining and the like of the conventional roller, improving the bearing capacity and service life of the roller, reducing the machining difficulty, ensuring the machining feasibility, and being suitable for planetary roller screw pairs with different tooth angles, and particularly suitable for improving the bearing capacity and service life of the small-pitch planetary roller screw pair.
The technical scheme adopted for solving the technical problems is as follows:
the invention provides a roller design method of an easy-to-process small-pitch planetary roller screw pair, which comprises the following steps of
Designing roller thread teeth;
the tooth-shaped roller threads are designed in the roller full-segment areas;
designing gears at two ends of a roller, wherein the diameter of the addendum circle of the gear is equal to the major diameter of the thread of the roller;
and (3) performing pitch diameter modification on the roller threads in the gear areas, wherein the profile of the roller thread profile is kept unchanged, so that when the planetary roller screw pair receives an axial rated dynamic load, the roller threads in the gear areas at two sides are contacted with the external threads of the screw or the internal threads of the nuts.
Further, the roller thread flanks are rounded flanks.
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 alpha r The three adjacent thread original triangles are marked as a first thread tooth, a second thread tooth and a third thread tooth, and respectively make tangent circles on the right tooth side of the first thread tooth, the left and right tooth sides of the second thread tooth and the left tooth side of the third thread tooth, the circle center of the tangent circle is positioned on the axis of the roller, and the tangent point is the intersection point of the tooth side and the thread pitch diameter;
s1.2, making root circles at the bottoms of tooth sockets among three thread teeth, wherein the root circles are tangential to circles of adjacent two tooth sides in the step S1.1;
s1.3, drawing a large-diameter line of the roller thread, and respectively selecting a left circular arc, a right circular arc, a root circular arc and a crest on a left tooth side tangent circle of the second thread, a right tooth side tangent circle of the second thread, two root tangent circles and a large meridian to form a continuous thread.
Further, the flank angle alpha r The range is 30-45 degrees.
Further, the gear is an involute straight tooth cylindrical gear and is machined by a hobbing method.
Further, the gear area thread pitch diameter modification amount is
The pitch diameter value of the thread in the gear area is
Wherein d r For the pitch diameter value, d, of the roller thread before modification rM Thread pitch diameter value for two-sided gear regionThe method comprises the steps of carrying out a first treatment on the surface of the 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 meshing;
the flank angle is alpha r 。
The invention also provides a roller of the easy-to-process small-pitch planetary roller screw pair, 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 all comprise single-line external threads, the external thread profiles are the same, the intermediate diameter of the threads on the first gear and the second gear is modified, and when the planetary roller screw pair receives an axial rated dynamic load after modification, roller threads in the gear areas on two sides are contacted with the external threads of the screw or the internal threads of the nuts.
Further, the external thread tooth type is an arc tooth side, and the gear adopts an involute straight tooth cylindrical gear.
Compared with the prior art, the invention has the beneficial effects that:
the invention provides a roller design method of a high-bearing and easy-to-process small-pitch planetary roller screw pair, which has the following advantages: 1) The roller thread design of the planetary roller screw pair suitable for different tooth flank angles is strong in universality; 2) The thread-gear mixed design is adopted, so that the length of the engaged thread is increased, and the contact ratio and the transmission stability of the roller gear and the gear ring are improved; 3) The three-section type thread pitch diameter modification is adopted, so that the uniform load distribution state of the load in the roller thread region is improved, the maximum load born by discontinuous thread teeth in the gear region is reduced, the ultimate 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 after the trimming and the middle area between the two gears of the roller are fixed values, the profile of the tooth is the same, and the thread can be processed by adopting a molding thread cutter with one specification, so that the processing difficulty is greatly reduced, and the manufacturing difficulty of the small-pitch planetary roller screw pair is solved.
Drawings
The accompanying drawings, which are included to provide a further understanding of 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 evident that the drawings in the following description are only some embodiments of the present invention and that other drawings may be obtained from these drawings without inventive effort for a person of ordinary skill in the art.
FIG. 1 is a block diagram of a planetary roller screw pair;
FIG. 2 is a first roller configuration;
FIG. 3 is a second roller configuration;
FIG. 4 is a roller thread form diagram provided by an embodiment of the present invention;
FIG. 5 is a basic profile of a roller thread provided in accordance with an embodiment of the present invention;
FIG. 6 is a roller thread form design provided in an embodiment of the present invention;
FIG. 7 is a three-segment roller thread pitch diameter modification provided in accordance with an embodiment of the present invention;
FIG. 8 is a schematic diagram of a roller thread pitch diameter modification relationship provided by an embodiment of the present invention.
Wherein the above figures include the following reference numerals:
1. screw, 2, roller, 3, nut, 4, ring gear, 5, cage, 6, gear, 7, roller threads, 7-1, left tooth side, 7-2, right tooth side, 7-3, root arc, 7-4, crest, 7-5, thread pitch line, 8, cylindrical shaft, 9, roller axis, 10, external thread raw triangle, 10-1, raw triangle left tooth side, 10-2, raw triangle right tooth side, 11, second thread tooth, 11-1, second thread tooth left tooth perpendicular, 11-2, second thread tooth left tooth tangent circle, 11-3, second thread tooth right tooth perpendicular, 11-4, second thread tooth right tooth tangent circle, 12, first thread tooth, 12-1, first thread tooth right tooth perpendicular, 12-2, first thread tooth right tooth tangent circle, 13, third thread tooth, 13-1, third thread tooth left tooth perpendicular, 13-2, third thread tooth left tooth tangent line, 14, 16, thread tooth right tooth line, 16, intermediate thread tooth diameter region, 17.
Detailed Description
Specific embodiments of the present invention are described in detail below. 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. It will be apparent, however, 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 due to unnecessary details, only the device structures and/or processing steps closely related to the aspects of the present invention are shown in the drawings, while other details not greatly related to the present invention are omitted.
The invention provides a roller design method of a high-bearing and easy-to-process small-pitch planetary roller screw pair, which comprises a thread tooth design, a gear design and a thread pitch modification mode, wherein the roller adopts an external thread based on an arc tooth side to realize efficient engagement with a screw and a nut, meanwhile, both ends of the roller adopt involute straight-tooth cylindrical gears, and in addition, the overall thread pitch design of the roller adopts a three-section modification mode.
The invention provides a roller design method of an easy-to-process small-pitch planetary roller screw pair, which comprises the following steps:
s1, designing roller thread teeth, and adopting arc tooth sides.
Specifically, the design method of the circular arc tooth side is as follows,
s1.1, designing the flank angle to be alpha r The three adjacent thread original triangles are marked as a first thread tooth, a second thread tooth and a third thread tooth, tangential circles of the right tooth side of the first thread tooth, the left tooth side of the second thread tooth, the right tooth side of the second thread tooth and the left tooth side of the third thread tooth are respectively made, the circle center of the tangential circle is positioned on the axis of the roller, and the tangential points are the intersecting points of the tooth sides and the pitch diameter line of the thread.
S1.2, making root circles at the bottoms of tooth sockets among the three thread teeth, wherein the root circles are tangential to circles of adjacent two tooth sides in the step S1.1.
S1.3, drawing a large-diameter line of the roller thread, and respectively selecting a left circular arc, a right circular arc, a root circular arc and a crest on a left tooth side tangent circle of the second thread, a right tooth side tangent circle of the second thread, two root tangent circles and a large meridian to form a continuous thread.
S2, roller threads in the step S1 are designed in the roller full-segment areas.
S3, designing gears at two ends of the roller, wherein involute straight-tooth cylindrical gears are adopted, and the diameter of the addendum circle is equal to the major diameter of the roller thread.
S4, carrying out middle repair on roller threads in the gear areas, wherein the profile of the roller thread profile is kept unchanged, so that when the planetary roller screw pair receives rated load, the roller threads in the gear areas at two sides are just contacted with external threads of the screw or internal threads of the nuts.
The technical scheme of the invention is described in detail below in connection with a specific embodiment.
As shown in fig. 3, the roller 2 of the easy-to-process small-pitch planetary roller screw pair comprises a gear 6, roller threads 7 and a cylindrical shaft 8, wherein the roller 2 adopts roller threads 7 based on arc tooth sides, the roller threads cover the whole section area of the roller to realize efficient engagement with the screw and the nut, the two ends of the roller 2 adopt involute straight-tooth cylindrical gears 6, and the design of the pitch diameter of the roller 2 adopts a three-section type repairing mode. In the planetary roller screw pair, roller threads 7 of rollers 2 are meshed with threads of a screw 1 and a nut 3, gears 6 at two ends of the rollers 2 are meshed with a gear ring 4, and cylindrical shafts 8 at two ends of the rollers are matched with holes in a retainer 5.
As shown in fig. 4, 5 and 6, the roller 2 of the small-pitch planetary roller screw pair adopts a single-thread form, the thread sides are circular arc, and the left tooth side 7-1 and the right tooth side 7-2 of the thread are symmetrically distributed. The following describes the thread form design process of the roller thread from a theoretical point of view: drawing 3 tooth flank angles as alpha r Comprises a first thread tooth 12, a second thread tooth 11 and a third thread tooth 13, and each thread tooth comprises an original triangle left tooth side 10-1 and an original triangle right tooth side 10-2. Respectively determining the intersection points of the left tooth side 10-1 of the original triangle, the right tooth side 10-2 of the original triangle and the pitch diameter 7-5 of the thread, and respectively taking the intersection points as left teethThe perpendicular lines of the sides 10-1 and the right flank 10-2 are used for obtaining a left flank perpendicular line 11-1 and a right flank perpendicular line 11-3 of the second thread 11, and the intersection point of the perpendicular line 11-1 and the roller axis 9 and the intersection point of the perpendicular line 11-3 and the roller axis 9 are respectively used as circle centers, so that the left flank perpendicular line 11-1 and the right flank perpendicular line 11-3 of the second thread
For the radius drawing circle, a left flank circle 11-2 and a right flank circle 11-4 of the second thread 11 are obtained. Wherein d r For the pitch diameter of the roller thread 7, i.e. the pitch diameter value, alpha r For the flank angle of the roller thread 7, a small pitch flank angle α is preferred r The range is 30-45 degrees.
For the first thread 12, determining the intersection point of the right flank 10-2 of the original triangle and the thread pitch diameter 7-5, and taking the perpendicular to the right flank 10-2 of the first thread through the intersection point to obtain a right flank perpendicular 12-1 of the first thread, wherein the intersection point of the right flank perpendicular 12-1 of the first thread and the roller axis 9 is used as the center of a circle, so that
And drawing a circle for the radius to obtain a right-hand thread cutting circle 12-2 of the first thread.
For the third thread 13, determining the intersection point of the original triangle left thread side 10-1 and the thread pitch diameter 7-5, and taking the perpendicular to the third thread left thread side 10-1 as the intersection point to obtain a third thread left thread side perpendicular 13-1, wherein the intersection point of the third thread left thread side perpendicular 13-1 and the roller axis 9 is used as the center of a circle, and the center is
And drawing a circle for the radius to obtain a third thread left-hand thread cutting circle 13-2.
A large diameter line 14 of the roller thread is drawn. A root tangent circle 15 with the radius r is formed at the bottom of the thread groove, and the root tangent circle 15 is simultaneously tangent with the left tooth side tangent circle 11-2 of the second thread and the right tooth side tangent circle 12-2 of the first thread; the root tangent circle 15 with the radius r is made at the bottom of the thread groove, and is simultaneously tangent with the right tooth side tangent circle 11-4 of the second thread and the left tooth side tangent circle 13-2 of the third thread. The selection principle of r is to ensure that the tooth bottom height is larger than the tooth top heights of the screw 1 and the nut 3 in the planetary roller screw pair. On the basis, on the left flank tangent circle 11-2, the right flank tangent circle 11-4 and the root tangent circle 15 of the second thread, a left circular arc 7-1, a right circular arc 7-2 and a root circular arc 7-3 are selected, and the thread teeth of the roller 2 are formed together with the crest 7-4. Wherein crest 7-4 is the portion of major meridian 14 between left-hand arc 7-1 and right-hand arc 7-2.
As shown in fig. 7 and 8, the roller thread 7 is designed in the whole-segment region of the roller, so that the effective length of the roller thread under a large load is improved; 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 major diameter of the thread of the roller, and the gears 6 adopt a hobbing method.
The design is carried out by adopting a method for repairing the pitch diameter of the thread and keeping the profile of the tooth shape unchanged. The pitch diameter of the thread of the roller 2 is divided into 3 sections in the whole length, wherein the two side gear areas 18 are respectively positioned at the 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 lower, 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 two side gear areas 18 are just contacted with the external threads of the screw 1 or the internal threads of the nut 3. The roller thread pitch diameter of the intermediate region 17 remains unchanged. The calculation formula of the thread pitch diameter correction quantity of the gear areas at two sides is as follows
The pitch diameter of the thread in the two-sided gear region 18 is
Wherein d r For the pitch diameter of the roller before modification, i.e. the pitch diameter of the intermediate zone 17, d rM The pitch diameter value of the gear areas 18 on both sides is delta, and delta is the deformation of the roller thread when the planetary roller screw pair reaches the specified axial rated dynamic load and only the thread length of the middle section participates in meshing. The deformation can be obtained by numerical calculation or finite element simulationWhen the deformation is obtained, only the threads of the middle section participate in load analysis, and the gear areas at the two ends do not carry out load analysis.
By reducing the pitch diameter of the threads of the gear areas, the tooth thickness at the thread contact point is reduced, a certain amount of gaps are ensured between the thread sides of the gear areas 18 on the two sides and the thread sides 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 born by discontinuous thread teeth of the gear areas 18 on the two sides is reduced, the failure damage of the threads due to overload is avoided, and the ultimate bearing capacity of the planetary roller screw pair is improved.
According to the roller of the small-pitch planetary roller screw pair based on thread pitch modification, threads can be turned by adopting the forming circular arc threading tool with one specification, the thread processing efficiency can be effectively improved, and particularly for small-pitch threads, the processability of the modified threads is good, and the dimensional accuracy 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 the embodiments are apparent from the detailed specification, and thus, it is intended by the appended claims to cover all such features and advantages of the 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 of the preferred embodiments of the present invention and is not intended to limit the present invention, but various modifications and variations can be made to the present invention by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
The invention is not described in detail in a manner known to those skilled in the art.
Claims (7)
1. A roller design method of an easy-to-process small-pitch planetary roller screw pair is characterized by comprising the following steps of
Designing roller thread teeth;
the tooth-shaped roller threads are designed in the roller full-segment areas;
designing gears at two ends of a roller, wherein the diameter of the addendum circle of the gear is equal to the major diameter of the thread of the roller;
the roller threads in the gear areas are subjected to pitch diameter modification, and the profile of the roller thread profile is kept unchanged, so that when the planetary roller screw pair receives an axial rated dynamic load, the roller threads in the gear areas on two sides are contacted with the external threads of the screw or the internal threads of the nuts;
the gear area thread pitch diameter modification amount is
The pitch diameter value of the thread in the gear area is
Wherein d r For the pitch diameter value, d, of the roller thread before modification rM The pitch diameter value of the threads in the gear areas at the 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 meshing;
α r is the flank angle.
2. The roller design method of claim 1, wherein the roller thread profile is a circular arc flank.
3. The roller design method according to claim 2, wherein the roller thread profile design method of the circular arc flanks is as follows
S1.1, designing the flank angle to be alpha r The three adjacent thread original triangles are marked as a first thread tooth, a second thread tooth and a third thread tooth, and respectively make tangent circles on the right tooth side of the first thread tooth, the left and right tooth sides of the second thread tooth and the left tooth side of the third thread tooth, the circle center of the tangent circle is positioned on the axis of the roller, and the tangent point is the intersection point of the tooth side and the thread pitch diameter;
s1.2, making root circles at the bottoms of tooth sockets among three thread teeth, wherein the root circles are tangential to circles of adjacent two tooth sides in the step S1.1;
s1.3, drawing a large-diameter line of the roller thread, and respectively selecting a left circular arc, a right circular arc, a root circular arc and a crest on a left tooth side tangent circle of the second thread, a right tooth side tangent circle of the second thread, two root tangent circles and a large meridian to form a continuous thread.
4. A roller design method according to claim 3, characterized in that the flank angle α r The range is 30-45 degrees.
5. The roller design method according to claim 1, wherein the gear is an involute spur gear, and is machined by a hobbing method.
6. The roller of the easy-to-process small-pitch planetary roller screw pair is characterized by being obtained by adopting the roller design method of any one of claims 1-5, and comprising 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 all comprise single-wire external threads, the external thread profile is the same, the middle diameter of the threads on the first gear and the second gear is modified, and when the planetary roller screw pair receives an axial rated dynamic load after the modification, roller threads in the two-side gear areas are in contact with the external threads of the screw or the internal threads of the nuts.
7. The roller of claim 6, wherein the external thread profile is a circular arc profile and the gear is an involute spur gear.
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| CN116989110B (en) * | 2023-09-27 | 2023-12-12 | 江西炬龙精密科技有限公司 | Uniform load planetary roller screw pair |
| CN117588539B (en) * | 2024-01-17 | 2024-04-05 | 杭州新剑机电传动股份有限公司 | Planetary roller screw |
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| CN107023620B (en) * | 2017-05-16 | 2019-01-18 | 哈尔滨工业大学 | A kind of high rigidity planetary roller screw based on roller screws central diameter repairing type |
| FR3088398B1 (en) * | 2018-11-08 | 2020-10-30 | Folly Abevi | SATELLITE SCREW MECHANISM |
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