CN117588539B - Planetary roller screw - Google Patents
Planetary roller screw Download PDFInfo
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- CN117588539B CN117588539B CN202410065014.5A CN202410065014A CN117588539B CN 117588539 B CN117588539 B CN 117588539B CN 202410065014 A CN202410065014 A CN 202410065014A CN 117588539 B CN117588539 B CN 117588539B
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- 230000008859 change Effects 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
- 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
- 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
- F16H25/24—Elements essential to such mechanisms, e.g. screws, nuts
- F16H2025/2445—Supports or other means for compensating misalignment or offset between screw and nut
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Abstract
The invention relates to the technical field of roller screws, in particular to a planetary roller screw. The screw rod comprises a screw rod, a nut and a plurality of rollers, wherein the outline of the screw rod work bearing side tooth is parabolic, and the outline of the nut work bearing side tooth is parabolic; the axial tooth profile of the roller external thread comprises a first work bearing side tooth profile and a second work bearing side tooth profile, and the first work bearing side tooth profile and the second work bearing side tooth profile are circular arcs or elliptical arcs; a first concave-convex spiral pair with parabola matched with an arc or an elliptical arc is formed between the roller and the screw rod, and a second concave-convex spiral pair with parabola matched with the arc or the elliptical arc is formed between the roller and the nut. The invention increases the number of meshing points when the roller is meshed with the screw rod and the nut, and the axial tooth profile has the characteristic of aligning, thereby greatly reducing the sensitivity of the planetary roller screw rod to the inclination of the axis caused by complex and severe working environment.
Description
Technical Field
The invention relates to the technical field of roller screws, in particular to a planetary roller screw.
Background
The planetary roller screw is used as a precise power transmission mechanism, integrates the motion characteristics of a planetary gear train, the ball screw and a needle bearing, and can realize the interconversion of rotary motion and linear motion. The meshing performance of the spiral curved surface formed among the screw rod, the roller and the nut in the planetary roller screw rod directly determines the transmission performance of the planetary roller screw rod. At present, the main problems of the spiral tooth surface meshing pair are as follows: firstly, the meshing and bearing capacity are unstable, and the bearing capacity at the edge of the spiral pair is poor; secondly, the existing spiral pairs such as straight lines, circular shapes and the like are in single-point engagement, and the bearing capacity is limited; thirdly, the existing spiral pair such as straight line and circular shape is sensitive to axial inclination, and especially when the tooth type of the spiral pair is modified improperly, the roller is easy to be blocked between the screw rod and the screw rod nut, so that the transmission capacity is lost. In order to further improve the transmission performance of the planetary roller screw and the bearing capacity, screw pair tooth design is always a research hotspot for researchers and industry-leading enterprises.
Disclosure of Invention
Aiming at the technical problem that the traditional roller screw has defects, the invention provides the planetary roller screw, which improves the axial tooth profile of the screw, the nut and the roller, thereby increasing the number of meshing points when the roller is meshed with the screw and the nut, and the axial tooth profile has the characteristic of aligning, and greatly reducing the sensitivity of the planetary roller screw to the axis inclination caused by complex and severe working environment.
In order to solve the problems, the technical scheme provided by the invention is as follows:
a planetary roller screw comprises a screw, a nut and a plurality of rollers, wherein the rollers are uniformly distributed between the nut and the screw along the circumferential direction; the axial tooth profile of the external screw thread of the screw rod comprises a screw rod work bearing side tooth profile, and the screw rod work bearing side tooth profile is parabolic; the axial tooth profile of the roller external thread comprises a first work bearing side tooth profile and a second work bearing side tooth profile, and the first work bearing side tooth profile and the second work bearing side tooth profile are arc or elliptical arc; the axial tooth profile of the nut internal thread comprises a nut work bearing side tooth profile, and the nut work bearing side tooth profile is parabolic; the first work bearing side tooth profile is abutted with the screw work bearing side tooth profile to form meshing points P1 and P2, so that a first concave-convex spiral pair with parabola matched with circular arc or elliptical arc is formed between the roller and the screw; the roller is in transmission connection with the screw rod through a first concave-convex screw pair; the P1 and the P2 are symmetrical by taking the central line of the parabola as a symmetry axis; the second work bearing side tooth profile is abutted with the nut work bearing side tooth profile to form meshing points P3 and P4, so that a second concave-convex spiral pair with parabola matched with circular arc or elliptical arc is formed between the roller and the nut; the roller is in transmission connection with the nut through a second concave-convex spiral pair; and the P3 and the P4 are symmetrical by taking the central line of the parabola as a symmetry axis.
Optionally, a parabolic tangent passing through the engagement points P1 and P2 forms a first angle a101 and a second angle a102 with a plane Q perpendicular to the central axis of the screw, respectively; a parabolic tangent passing through the meshing points P3 and P4 and a plane Q perpendicular to the central axis of the screw form a third angle a103 and a fourth angle a104 respectively; wherein the first angle a101 and the third angle a103 are 30 ° to 60 °; the second angle a102 and the fourth angle a104 are 40 ° to 70 °.
Optionally, the axial profile of the external screw thread of the screw rod further comprises a non-working bearing side profile of the screw rod, and the non-working bearing side profile of the screw rod is parabolic or linear; the axial tooth profile of the nut internal thread also comprises a nut non-working bearing side tooth profile, and the nut non-working bearing side tooth profile is parabolic or linear.
Optionally, when the non-working bearing side profile of the screw is a straight line, an engagement point P5 is formed on the non-working bearing side profile of the screw, and a tangent line passing through the engagement point P5 and a plane Q perpendicular to the central axis of the screw form a fifth angle a105; when the non-working bearing side tooth profile of the nut is a straight line, an engagement point P6 is formed on the non-working bearing side tooth profile of the nut, and a tangent line passing through the engagement point P6 and a plane Q perpendicular to the central axis of the screw rod form a sixth angle a106; wherein, the fifth angle a105 and the sixth angle a106 are 45 degrees.
Optionally, the device further comprises two retainers and two annular gears; the two inner gear rings are respectively fixed at two ends of the nut, inner teeth are arranged on the inner ring of the inner gear ring, and outer teeth meshed with the inner teeth are respectively arranged at two ends of the roller; the retainers are positioned on the inner side of the annular gear, and two ends of the roller are respectively embedded with the two retainers.
Optionally, the first work load bearing side profile and the second work load bearing side profile are symmetrically arranged.
Optionally, the first and second work load bearing side profile are asymmetrically arranged.
Optionally, arc transition is adopted at the tooth crest and the tooth root of the axial tooth profile of the external screw thread of the lead screw; arc transition is adopted at the tooth crest and the tooth root of the axial tooth profile of the internal thread of the nut; arc transition is adopted at the tooth crest and the tooth root of the axial tooth profile of the roller external thread.
Optionally, the internal thread of the nut and the external thread of the screw have the same number of heads, and the number of heads is at least one.
Optionally, the roller external thread is a single start thread.
Advantageous effects
Compared with the prior art, the technical scheme provided by the invention has the following beneficial effects:
(1) The invention changes the original single-point meshing spiral transmission of the straight line and the convex arc into convex-concave spiral transmission based on multi-point meshing between the parabola and the arc, and changes the transmission between the roller and the screw into the spiral transmission of convex-concave multi-point meshing by designing the axial tooth profile of the screw and the nut into the tooth profile containing the parabola shape and designing the tooth profile of the roller into the tooth profile containing the arc. Therefore, the planetary roller screw is superior to the conventional linear tooth profile and circular arc tooth profile in engagement characteristic, so that the problems of instability in engagement, reduction in bearing capacity caused by change of engagement points and the like can be effectively avoided, and the bearing capacity of the roller screw is greatly improved.
(2) Based on the design of the axial tooth profile of the screw rod, the nut and the roller, the concave parabola wraps the convex arc or the elliptic arc, so that the active aligning function is realized, errors caused by misalignment of axes and deformation of the device can be compensated, and the sensitivity to axis inclination caused by manufacturing, assembly and complex and severe working environments is greatly reduced.
Drawings
Fig. 1 is a schematic structural view of a planetary roller screw according to an embodiment of the present invention.
Fig. 2 is a schematic view of the engagement of the screw, rollers and nuts according to an embodiment of the present invention.
Fig. 3 is a schematic structural view of an axial profile of an external screw thread of a screw according to an embodiment of the present invention.
Fig. 4 is a schematic structural view of an axial profile of an internal thread of a nut according to an embodiment of the present invention.
Fig. 5 is a schematic view of the engagement of rollers and screws according to an embodiment of the present invention.
Fig. 6 is a schematic view of the engagement of the roller and the nut according to an embodiment of the present invention.
Fig. 7 is a schematic diagram of a centering function according to an embodiment of the present invention.
Fig. 8 is an enlarged schematic view at II-II in fig. 7.
Fig. 9 is an enlarged schematic view at III-III in fig. 7.
Detailed Description
For a further understanding of the present invention, the present invention will be described in detail with reference to the drawings and examples.
The present application is described in further detail below with reference to the drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be noted that, for convenience of description, only the portions related to the invention are shown in the drawings. The first, second, etc. words are provided for convenience in describing the technical scheme of the present invention, and have no specific limitation, and are all generic terms, and do not constitute limitation to the technical scheme of the present invention. It should be noted that, in the case of no conflict, the embodiments and features in the embodiments may be combined with each other. In the description of the present invention, it should be noted that the directions or positional relationships indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. are based on the directions or positional relationships shown in the drawings, are merely for convenience of describing the present invention and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance. Unless specifically stated or limited otherwise, the terms "mounted," "connected," and "coupled" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present invention will be understood in specific cases by those of ordinary skill in the art. The technical schemes in the same embodiment and the technical schemes in different embodiments can be arranged and combined to form a new technical scheme without contradiction or conflict, which is within the scope of the invention.
Example 1
With reference to fig. 1-9, the embodiment provides a planetary roller screw, aiming at the defects of unstable meshing and bearing capacity, easy clamping of rollers, insufficient bearing capacity and the like of the traditional roller screw, and the axial tooth profile of a screw 1, a nut 3 and a roller 2 is improved, so that the number of meshing points when the roller 2 is meshed with the screw 1 and the nut 3 is increased, and the axial tooth profile related to the embodiment has the characteristic of aligning, so that the sensitivity of the planetary roller screw to axis inclination caused by complex and severe working environments is greatly reduced.
With reference to fig. 1, in order to achieve the purpose of the invention, the planetary roller screw of this embodiment includes a screw 1, a nut 3 and a plurality of identical rollers 2, and the plurality of rollers 2 are uniformly distributed between the nut 3 and the screw 1 along the circumferential direction, and similar to the working principle of the conventional roller screw, the rollers 2 of this embodiment simultaneously perform screw transmission with the screw 1 and the nut 3, that is, the transmission connection between the nut 3 and the screw 1 is achieved through the rollers 2.
Further, referring to fig. 2-6, in this embodiment, the axial profile of the external thread of the screw 1 includes a screw work load flank profile 111, and the screw work load flank profile 111 is parabolic. The axial profile of the external thread of the roller 2 comprises a first work load flank profile 211 and a second work load flank profile 212, the first work load flank profile 211 and the second work load flank profile 212 being circular or elliptical. And, the axial profile of the internal thread of the nut 3 comprises a nut work load flank profile 311, the nut work load flank profile 311 being parabolic.
In the planetary roller screw of the present embodiment, during normal operation, the first work load bearing side tooth profile 211 abuts against the screw work load bearing side tooth profile 111 to form engagement points P1 and P2, so that a first concave-convex screw pair with a parabola matched with an arc or an elliptical arc is formed between the roller 2 and the screw 1, and at this time, transmission is realized between the roller 2 and the screw 1 through the first concave-convex screw pair. The second work load-bearing side tooth profile 212 abuts against the nut work load-bearing side tooth profile 311 to form engagement points P3 and P4, and therefore a second concave-convex screw pair with parabola matched with circular arc or elliptical arc is formed between the roller 2 and the nut 3, and at the moment, transmission is realized between the roller 2 and the nut 3 through the second concave-convex screw pair. Wherein the meshing points P1 and P2 are symmetrical with the central line of the parabola as a symmetry axis; the engagement points P3 and P4 are axisymmetric about the centerline of the parabola in which they are located.
It can be seen that, for the planetary roller screw of the present embodiment, since there are engagement points P1, P2, P3 and P4, unlike the existing single point engagement manner of the straight thread profile and the circular arc profile, the present embodiment increases the number of engagement points of each pair of thread profiles to two, thereby being capable of bearing axial and radial loads more.
Based on the structural design of the embodiment, the self-aligning function can be realized, and the sensitivity to axis inclination caused by complex and severe working environments can be greatly reduced. The corresponding working principle is as follows:
referring to fig. 7-9, fig. 7 shows a situation that the planetary roller screw 1 of the present embodiment is inclined with respect to the axis X '-X' of the nut 3 due to manufacturing, assembling or severe working conditions, and the roller 2 is inclined in various ways.
Fig. 8 shows a tilting situation of the roller 2, and fig. 8 shows an enlarged schematic view of the engagement of the roller 2 with the axial section of the screw 1 when the roller 2 is tilted as shown at II-II in fig. 7. In fig. 8, the meshing points P1 and P2 are taken as observation objects, and benefit from the design of the axial tooth profile of the roller 2 and the screw 1 according to the embodiment, when the roller 2 is slightly inclined or dithered, the positions of the meshing points P1 and P2 formed by the abutting connection of the first work load-bearing side tooth profile 211 and the screw work load-bearing side tooth profile 111 can be kept unchanged, and the positions of the meshing points P3 and P4 formed by the abutting connection of the second work load-bearing side tooth profile 212 and the nut work load-bearing side tooth profile 311 can be kept unchanged, so that the stability of the radial relative positions of the screw 1 and the nut 3 is ensured.
That is, the planetary roller screw of the present embodiment can still normally operate without seizing when the roller 2 is slightly inclined or dithered, based on the first concave-convex screw pair in which the parabola formed between the roller 2 and the screw 1 is fitted with an arc or an elliptical arc and the second concave-convex screw pair in which the parabola formed between the roller 2 and the nut 3 is fitted with an arc or an elliptical arc in the present embodiment.
Fig. 9 shows another inclination of the roller 2, and fig. 9 shows an enlarged view of the engagement of the roller 2 with the axial section of the screw 1 when the roller 2 is inclined as shown at III-III in fig. 7. This increases the pitch of the screw 1, the nut 3 and leads to an increase in the radius of curvature of the curve of the engagement surface. In fig. 9, the engagement points P1 and P2 are observed, and at this time, the engagement points P1 and P2 move toward the center line C-C of the concave parabola to P1 'and P2', and even the engagement points P1 and P2 may be combined into one. However, even if the meshing points P1 and P2 are close to each other and even merge into one meshing point, at least one meshing point still exists between the roller 2 and the screw 1, and the first concave-convex spiral pair formed by the parabola formed between the roller 2 and the screw 1 and matched with the circular arc or the elliptical arc can still ensure the work, so that the planetary roller screw can still normally operate in a short time. Moreover, as the planetary roller screw continues to operate, under the cooperation of the screw work load bearing side profile 111 and the first work load bearing side profile 211, and the cooperation of the nut work load bearing side profile 311 and the second work load bearing side profile 212, the inclination degree between the roller 2 and the nut 3 is continuously reduced until the axes of the screw 1, the roller 2 and the nut 3 return to the normal state, thereby playing a role of aligning. And, because there are two meshing points, the aligning process is further enhanced. The situation when the meshing points P3 and P4 are taken as the observation objects is similar to the situation when the meshing points P1 and P2 are taken as the observation objects, the principle is consistent, the meshing points P3 and P4 can move towards the central line C-C of the concave parabola, even the meshing points P3 and P4 can be combined into one, but at the moment, the planetary roller screw can still normally operate in a short time, the inclination degree between the roller 2 and the nut 3 can be continuously reduced until the axes of the screw 1, the roller 2 and the nut 3 return to the normal state, and the aligning effect is achieved.
It is conceivable that the other rollers 2 may be inclined, either in one of the two cases described above, or coupled and alternate during the turnaround operation. In a word, the planetary roller screw according to the embodiment can ensure the normal operation of the axial line tilting of the roller 2 based on the design of the axial tooth profile of the screw 1, the nut 3 and the roller 2, and simultaneously can promote the reduction of the axial line tilting degree, thereby greatly reducing the sensitivity to the axial line tilting caused by manufacturing, assembling and complex and severe working environments.
Alternatively, the first and second work load bearing side profile 211, 212 on the roller 2 may be symmetrically disposed or asymmetrically disposed. For example, in one embodiment, both use circular arc or elliptical arc, but the radii or curvature radii taken by both are not equal, so as to realize asymmetric arrangement, in another embodiment, both use circular arc and elliptical arc respectively, so as to realize asymmetric arrangement, and the purpose of the asymmetric arrangement is to change the stress condition at the meshing point, so as to play a better aligning role. In other embodiments, both use the same arc or elliptical arc, which can simplify design and machining difficulties to some extent.
In summary, compared with the conventional roller screw, the planetary roller screw of the present embodiment has at least the following advantages:
(1) The planetary roller screw of this embodiment changes the single point meshing screw transmission of the original straight line and the convex arc into the convex-concave screw transmission based on the multipoint meshing between the parabola and the arc, and changes the transmission between the roller 2 and the screw 1 into the convex-concave multipoint meshing screw transmission by designing the axial tooth profile of the screw 1 and the screw nut 3 to include the tooth profile of the parabola shape and designing the tooth profile of the roller 2 to include the tooth profile of the arc. Therefore, the planetary roller screw is superior to the conventional linear tooth profile and circular arc tooth profile in engagement characteristic, so that the problems of instability in engagement, reduction in bearing capacity caused by change of engagement points and the like can be effectively avoided, and the bearing capacity of the planetary roller screw is greatly improved.
(2) The planetary roller screw of the embodiment realizes the active aligning function by wrapping convex circular arcs or elliptical arcs by concave parabolas based on the design of the axial tooth profiles of the screw 1, the nut 3 and the roller 2, can compensate errors caused by misalignment of axes and deformation of devices, and greatly reduces the sensitivity to axis inclination caused by manufacturing, assembly and complex and severe working environments.
Example 2
With reference to fig. 3-6, compared with the technical solution of embodiment 1, the planetary roller screw of this embodiment can be improved as follows: the parabolic tangent passing through the meshing points P1 and P2 forms a first angle a101 and a second angle a102 with a plane Q perpendicular to the central axis of the screw 1, respectively; a parabolic tangent passing through the meshing points P3 and P4 and a plane Q perpendicular to the central axis of the screw 1 form a third angle a103 and a fourth angle a104 respectively; wherein the first angle a101 and the third angle a103 are 30 ° to 60 °; the second angle a102 and the fourth angle a104 are 40 ° to 70 °.
The engagement between the roller 2 and the screw 1, and between the roller 2 and the nut 3 is further designed in this embodiment, in which the first angle a101 and the third angle a103 are at least 30 ° and at most 60 °, if the angle is too small, friction is increased, power consumption is increased, and wear is increased, and if the angle is too large, load-carrying capacity is greatly reduced. In this embodiment, the second angle a102 and the fourth angle a104 have a size of at least 40 ° and at most 70 °, and as in the above case, if the angle is too small, friction force is increased, power consumption is increased, abrasion is increased, and if the angle is too large, load-carrying capacity is greatly reduced.
Example 3
Referring to fig. 3-4, compared with the technical solution of embodiment 1 or 2, a planetary roller screw of this embodiment can be improved as follows: the axial tooth profile of the external thread of the screw 1 further comprises a screw non-working bearing side tooth profile 112, and the screw non-working bearing side tooth profile 112 is parabolic or linear; the axial profile of the internal thread of the nut 3 also comprises a nut non-working load flank profile 312, the nut non-working load flank profile 312 being parabolic or linear.
When the planetary roller screw of the present embodiment is used in some application scenarios, the non-working bearing side profile 112 of the screw and the non-working bearing side profile 312 of the nut can be simplified to be linear to achieve the purpose of reducing the processing cost when a larger bearing capacity is required in only one direction.
It is contemplated that in other scenarios, where a planetary roller screw requires greater load capacity in a non-single direction, the screw non-working load flank profile 112 and the nut non-working load flank profile 312 may still be designed in a parabolic fashion to meet the use requirements.
Example 4
With reference to fig. 3-4, compared with the technical solution of at least embodiment 3, a planetary roller screw of this embodiment can be improved as follows: when the screw non-working bearing side tooth profile 112 is a straight line, an engagement point P5 is formed on the screw non-working bearing side tooth profile 112, and a tangent line passing through the engagement point P5 and a plane Q perpendicular to the central axis of the screw 1 form a fifth angle a105; when the nut non-working bearing side tooth profile 312 is a straight line, an engagement point P6 is formed on the nut non-working bearing side tooth profile 312, and a tangent line passing through the engagement point P6 and a plane Q perpendicular to the central axis of the screw rod 1 form a sixth angle a106; wherein, fifth angle a105 and sixth angle a106 are 45 degrees.
In this embodiment, the engagement between the roller 2 and the screw 1, and the engagement between the roller 2 and the nut 3 are further designed, in this embodiment, the fifth angle a105 and the sixth angle a106 are both 45 °, which is the same as the design of the first angle a101, the second angle a102, the third angle a103, and the fourth angle a104, and in view of the overall service life, the service performance, etc., if the angle is too small, the friction force is increased, the power consumption is increased, the wear is increased, and if the angle is too large, the load-carrying capacity is greatly reduced.
Example 5
With reference to fig. 1, compared with any one of the technical schemes in embodiments 1-4, a planetary roller screw of this embodiment can be improved as follows: the device also comprises two retainers 4 and two inner gear rings 5; the two inner gear rings 5 are respectively fixed at two ends of the nut 3, inner teeth are arranged on the inner ring of the inner gear rings 5, and outer teeth meshed with the inner teeth are respectively arranged at two ends of the roller 2; the retainers 4 are located inside the ring gear 5, and both ends of the roller 2 are fitted with the two retainers 4, respectively.
In this embodiment, there is circumferential external teeth at the two ends of the roller 2, and the external teeth mesh with the internal teeth of the ring gear 5, so that the roller 2 can be ensured to be uniformly distributed between the nut 3 and the screw 1 to a certain extent, the inclination of the axis caused by assembly or working condition causes is avoided, and the parallelism of the central axis of the roller 2 and the central axis of the screw 1 is ensured.
And, in the present embodiment, the planetary roller screw is further provided with a cage 4, and the cage 4 and the ring gear 5 are engaged with the rollers 2 for uniformly distributing the respective rollers 2 inside the nut 3.
Example 6
With reference to fig. 1-6, compared with any one of the technical schemes in embodiments 1-5, a planetary roller screw of the present embodiment can be improved as follows: arc transition is adopted at the tooth crest and the tooth root of the axial tooth profile of the external thread of the lead screw 1; arc transition is adopted at the tooth crest and the tooth root of the axial tooth profile of the internal thread of the nut 3; arc transition is adopted at the tooth crest and the tooth root of the axial tooth profile of the external thread of the roller 2.
Example 7
With reference to fig. 1-9, compared with any one of the technical schemes in embodiments 1-6, a planetary roller screw of the present embodiment can be improved as follows: the internal thread of the nut 3 has the same number of heads as the external thread of the screw 1, and the number of heads is at least one. In this embodiment, the same number of heads can ensure the engagement effect, and in general, the number of heads may be a single head, and three or more heads may be used when the bearing capacity needs to be improved.
Example 8
With reference to fig. 1-9, compared with any one of the technical schemes in embodiments 1-7, the planetary roller screw of the present embodiment can be improved as follows: the external thread of the roller 2 is a single-start thread.
The invention and its embodiments have been described above by way of illustration and not limitation, and the invention is illustrated in the accompanying drawings and described in the drawings in which the actual structure is not limited thereto. Therefore, if one of ordinary skill in the art is informed by this disclosure, the structural mode and the embodiments similar to the technical scheme are not creatively designed without departing from the gist of the present invention.
Claims (10)
1. The planetary roller screw is characterized by comprising a screw, a nut and a plurality of rollers, wherein the rollers are uniformly distributed between the nut and the screw along the circumferential direction;
the axial tooth profile of the external screw thread of the screw rod comprises a screw rod work bearing side tooth profile, and the screw rod work bearing side tooth profile is parabolic;
the axial tooth profile of the roller external thread comprises a first work bearing side tooth profile and a second work bearing side tooth profile, and the first work bearing side tooth profile and the second work bearing side tooth profile are arc or elliptical arc;
the axial tooth profile of the nut internal thread comprises a nut work bearing side tooth profile, and the nut work bearing side tooth profile is parabolic;
the first work bearing side tooth profile is abutted with the screw work bearing side tooth profile to form meshing points P1 and P2, so that a first concave-convex spiral pair with parabola matched with circular arc or elliptical arc is formed between the roller and the screw; the roller is in transmission connection with the screw rod through a first concave-convex screw pair; the P1 and the P2 are symmetrical by taking the central line of the parabola as a symmetry axis;
the second work bearing side tooth profile is abutted with the nut work bearing side tooth profile to form meshing points P3 and P4, so that a second concave-convex spiral pair with parabola matched with circular arc or elliptical arc is formed between the roller and the nut; the roller is in transmission connection with the nut through a second concave-convex spiral pair; and the P3 and the P4 are symmetrical by taking the central line of the parabola as a symmetry axis.
2. A planetary roller screw as claimed in claim 1, wherein,
a parabolic tangent passing through the meshing points P1 and P2 forms a first angle a101 and a second angle a102 with a plane Q perpendicular to the central axis of the screw rod respectively;
a parabolic tangent passing through the meshing points P3 and P4 and a plane Q perpendicular to the central axis of the screw form a third angle a103 and a fourth angle a104 respectively;
wherein the first angle a101 and the third angle a103 are 30 ° to 60 °; the second angle a102 and the fourth angle a104 are 40 ° to 70 °.
3. A planetary roller screw according to claim 1 or 2, characterized in that,
the axial tooth profile of the external screw thread of the screw rod further comprises a non-working bearing side tooth profile of the screw rod, and the non-working bearing side tooth profile of the screw rod is parabolic or linear;
the axial tooth profile of the nut internal thread also comprises a nut non-working bearing side tooth profile, and the nut non-working bearing side tooth profile is parabolic or linear.
4. A planetary roller screw as claimed in claim 3, wherein,
when the non-working bearing side tooth profile of the screw rod is a straight line, an engagement point P5 is formed on the non-working bearing side tooth profile of the screw rod, and a tangent line passing through the engagement point P5 and a plane Q perpendicular to the central axis of the screw rod form a fifth angle a105;
when the non-working bearing side tooth profile of the nut is a straight line, an engagement point P6 is formed on the non-working bearing side tooth profile of the nut, and a tangent line passing through the engagement point P6 and a plane Q perpendicular to the central axis of the screw rod form a sixth angle a106;
wherein, the fifth angle a105 and the sixth angle a106 are 45 degrees.
5. The planetary roller screw as claimed in claim 1, further comprising two retainers and two ring gears; the two inner gear rings are respectively fixed at two ends of the nut, inner teeth are arranged on the inner ring of the inner gear ring, and outer teeth meshed with the inner teeth are respectively arranged at two ends of the roller; the retainers are positioned on the inner side of the annular gear, and two ends of the roller are respectively embedded with the two retainers.
6. The planetary roller screw as claimed in claim 1, wherein the first and second work load bearing side profile are symmetrically disposed.
7. A planetary roller screw as claimed in claim 1, wherein the first and second work load flank profile are asymmetrically arranged.
8. The planetary roller screw as claimed in claim 1, wherein the axial tooth profile of the screw external thread has a tooth crest and a tooth root each having a circular arc transition; arc transition is adopted at the tooth crest and the tooth root of the axial tooth profile of the internal thread of the nut; arc transition is adopted at the tooth crest and the tooth root of the axial tooth profile of the roller external thread.
9. A planetary roller screw according to claim 1, characterized in that the internal thread of the nut and the external thread of the screw have the same number of starts, said number of starts being at least one.
10. A planetary roller screw as claimed in claim 1, wherein the roller external thread is a single start thread.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202410065014.5A CN117588539B (en) | 2024-01-17 | 2024-01-17 | Planetary roller screw |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202410065014.5A CN117588539B (en) | 2024-01-17 | 2024-01-17 | Planetary roller screw |
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| Publication Number | Publication Date |
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| CN117588539A CN117588539A (en) | 2024-02-23 |
| CN117588539B true CN117588539B (en) | 2024-04-05 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202410065014.5A Active CN117588539B (en) | 2024-01-17 | 2024-01-17 | Planetary roller screw |
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Citations (7)
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|---|---|---|---|---|
| GB846121A (en) * | 1956-11-16 | 1960-08-24 | Carl Bruno Strandgren | Improvements in or relating to screw and nut devices |
| JP2008111466A (en) * | 2006-10-30 | 2008-05-15 | Nsk Ltd | Ball screw |
| JP2008281184A (en) * | 2007-05-14 | 2008-11-20 | Nsk Ltd | Planetary roller screw device |
| CN111457071A (en) * | 2020-04-13 | 2020-07-28 | 中国船舶重工集团公司第七0四研究所 | Planetary roller screw with involute thread profile |
| CN111457070A (en) * | 2020-04-13 | 2020-07-28 | 中国船舶重工集团公司第七0四研究所 | Planetary roller screw with cycloidal thread profile |
| FR3098268A1 (en) * | 2019-07-05 | 2021-01-08 | Maateecs Consulting | ASYMMETRIC-TOOTHED SATELLITE ROLLER SCREWS |
| CN113757324A (en) * | 2021-08-19 | 2021-12-07 | 北京自动化控制设备研究所 | Roller design method for easy-to-machine small-pitch planetary roller screw pair and roller |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20190011026A1 (en) * | 2016-10-05 | 2019-01-10 | Delbert Tesar | Linear actuator based on ruggedized planetary screw |
| EP3406936B1 (en) * | 2017-05-22 | 2020-08-26 | Goodrich Actuation Systems SAS | Improved planetary screw mechanism |
-
2024
- 2024-01-17 CN CN202410065014.5A patent/CN117588539B/en active Active
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB846121A (en) * | 1956-11-16 | 1960-08-24 | Carl Bruno Strandgren | Improvements in or relating to screw and nut devices |
| JP2008111466A (en) * | 2006-10-30 | 2008-05-15 | Nsk Ltd | Ball screw |
| JP2008281184A (en) * | 2007-05-14 | 2008-11-20 | Nsk Ltd | Planetary roller screw device |
| FR3098268A1 (en) * | 2019-07-05 | 2021-01-08 | Maateecs Consulting | ASYMMETRIC-TOOTHED SATELLITE ROLLER SCREWS |
| CN111457071A (en) * | 2020-04-13 | 2020-07-28 | 中国船舶重工集团公司第七0四研究所 | Planetary roller screw with involute thread profile |
| CN111457070A (en) * | 2020-04-13 | 2020-07-28 | 中国船舶重工集团公司第七0四研究所 | Planetary roller screw with cycloidal thread profile |
| CN113757324A (en) * | 2021-08-19 | 2021-12-07 | 北京自动化控制设备研究所 | Roller design method for easy-to-machine small-pitch planetary roller screw pair and roller |
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| Publication number | Publication date |
|---|---|
| CN117588539A (en) | 2024-02-23 |
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