JP3232613U - Circulating planetary roller screw - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a circulating planetary roller screw capable of simplifying combination work and maintenance. A circulating planetary roller screw comprises a screw shaft, a nut 30, two reflux units 40 and a plurality of rollers. The nut has separate concave positioning portions 35 in the two invalid tooth areas. The two reflux units are mounted on both ends of the nut and have a guide portion 42 and a convex positioning portion 43 formed on the guide portion, respectively. The combination work is completed when the convex positioning portions of the two reflux units are fitted into the concave positioning portions of the nut. Since the plurality of rollers maintain the meshing state between the screw shaft and the nut by the annular groove, if the screw shaft rotates, the multiple rollers rotate around the screw shaft by the driving force of the screw shaft and at the same time, two recirculations occur. It is pushed out by the guide part of the unit and reciprocates along the axial direction of the screw shaft. [Selection diagram] Fig. 6

Description

The present invention relates to roller screws, especially circulating planetary roller screws.

In a conventional circulating planetary roller screw, a plurality of rollers are positioned between a screw shaft and a nut, and are arranged so as to be arranged at an equal angle with respect to the center of the screw shaft. The rollers are coaxial with the thread shaft by meshing with the outer thread of the thread shaft and the inner thread of the nut at the same time.
When the screw shaft rotates with respect to the nut, the plurality of rollers rotate around the screw shaft while rotating. As the rollers rotate around the screw shaft, the recirculation units located at both ends of the nut reciprocate the rollers along the axial direction of the screw shaft, so that between the rollers, the screw shaft and the nut. The line contact of the can significantly increase the rigidity, load capacity and impact resistance of the entire structure.

In a conventional circulating planetary roller screw, the reflux unit is fastened to both ends of the nut by a thread. However, the thread has a relatively high processing cost and a low margin of error. On the other hand, if a method is adopted in which the reflux unit is previously provided with a screw hole corresponding to the nut, then the reflux unit and the nut are combined and aligned, and then fixed with an adhesive, the work and combination of alignment are performed. There is a problem that maintenance after the operation is difficult.

The roller screwing device posted in Patent Document 1 ensures that the rollers are moved along the radial direction by cams located at both ends of the nut. As shown in FIGS. 9 and 12 of the draft, the cam is attached to the nut by fitting the key into the keyway of the nut. However, in order to place the key, it is necessary to increase the outer diameter of the nut, which also increases the cost.

US7,044,017 B2 Gazette

A main object of the present invention is to provide a circulating planetary roller screw that can simplify combination work and maintenance without limiting the outer diameter and length of the nut.

Circulating planetary roller screws for solving the above-mentioned problems include a screw shaft, a nut, two reflux units, a holder and a plurality of rollers. The screw shaft has an outer thread on the outer peripheral surface. The nut is mounted on the screw shaft so that it can move along the axial direction of the screw shaft and has a storage groove and an inner thread. Storage grooves are formed separately at both ends of the inner peripheral surface of the nut. The inner thread is formed on the inner peripheral surface of the nut and has two ineffective tooth areas and one effective tooth area. Each of the two invalid tooth areas is adjacent to a containment groove and has a concave positioning portion. The two reflux units are mounted on both ends of the nut and have an annular portion, an induction portion and a convex positioning portion, respectively. The annular portion is located in the nut storage groove. The induction portion projects to the side surface of the annular portion and is located in the invalid tooth area of the inner thread. The convex positioning portion projects to the outer surface of the guide portion and fits into the concave positioning portion of the nut. The holder is mounted between the screw shaft and the nut and has a plurality of holding grooves. The holding grooves are arranged in an annular shape at an equal angle with respect to the axial direction of the screw shaft. The plurality of rollers are separately mounted in the holding grooves of the holder, and each has an annular groove on the outer peripheral surface. The annular grooves are arranged at regular intervals along the axial direction. Multiple rollers mesh with the effective tooth area of the outer thread of the threaded thread and the inner thread of the nut by multiple annular grooves, so that the multiple rollers rotate in the axial direction of the threaded shaft while rotating due to the driving force of the threaded shaft. When the holder is synchronously rotated along the thread, the guides of the two recirculation units push out a plurality of rollers to reciprocate along the axial direction of the screw shaft.

Summarizing the features of the above-mentioned structure, the circulation type planetary roller screw according to the present invention combines the nut and the reflux unit together by the concave positioning portion of the invalid tooth area of the nut and the convex positioning portion of the reflux unit. Not only can the combination of the recirculation unit and the nut be simplified without limiting the outer diameter and length, but the recirculation unit can be quickly removed for maintenance.

When relatively preferred, the nut has separate radial threaded holes at both ends. The annular portion of the two reflux units has a positioning groove on the outer peripheral surface. The set screw is tightened in the radial screw hole, and the end portion is fitted into the positioning groove. Due to the structural features described above, the reflux unit can be controlled to move along the axial direction.

In a relatively preferred case, the width of the positioning groove is larger than the outer diameter of the set screw so that the reflux unit is pushed by the set screw and is not damaged or deformed.

When relatively preferred, the nut has two shoulders on its inner peripheral surface. The two shoulders are adjacent to the containment groove and the invalid tooth area of the medial thread, respectively. The annular portion of each of the two reflux units has an inner surface. The guide portion is formed on the inner surface. The two reflux units abut on the shoulder of the nut by the inner surface of the annular portion.

When relatively preferable, since the axial length of the concave positioning portion is larger than the axial length of the convex positioning portion, the inner side surfaces of the two reflux units can be reliably brought into contact with the shoulder portion of the nut.

When relatively preferred, the convex positioning portion is semi-circular or multi-sided.

The detailed structure, features, assembly or usage of the circulating planetary roller screw according to the present invention will be clarified through the detailed description of the following embodiments. It should be noted that the following detailed description and the embodiments presented by the present invention are merely examples for explaining the present invention, and it is common knowledge in the area related to the present invention that the scope of claims of the present invention cannot be limited. Then you should be able to understand.

It is a perspective view which shows the circulation type planet roller screw by 1st Embodiment of this invention. It is an exploded perspective view which shows the circulation type planet roller screw by 1st Embodiment of this invention. It is a top view which looked at the circulation type planet roller screw by 1st Embodiment of this invention from one end. It is sectional drawing along the 4-4 line in FIG. It is sectional drawing along the 5-5 line in FIG. It is sectional drawing which shows the state which the nut and the reflux unit are separated in the circulation type planetary roller screw by 1st Embodiment of this invention. It is sectional drawing which shows the state which the nut, the reflux unit and the roller are connected in the circulation type planet roller screw by 1st Embodiment of this invention. It is an enlarged view which shows a part of FIG. 7. It is sectional drawing which shows a part of the circulation type planetary roller screw by 1st Embodiment of this invention. It is a perspective view which shows the reflux unit of the circulation type planet roller screw by 2nd Embodiment of this invention. It is a perspective view which shows the reflux unit of the circulation type planet roller screw by the 3rd Embodiment of this invention.

Hereinafter, the circulating planetary roller screw according to the present invention will be described with reference to the drawings. In the specification and drawings, directional terms are expressed based on the directions in the drawings. The same reference numerals indicate structural features of the same or similar parts.

(First Embodiment)
As shown in FIGS. 1 and 2, the circulating planetary roller screw 10 according to the first embodiment of the present invention includes a screw shaft 20, a nut 30, two reflux units 40, a holder 50, and a plurality of rollers 60. In the present embodiment, the number of rollers 60 is eight, but the number of rollers 60 is not limited to eight.

The screw shaft 20 has an outer thread 22 on the outer peripheral surface.

The nut 30 is mounted on the screw shaft 20 so that it can move along the axial direction of the screw shaft 20 and has two storage grooves 31, an inner thread 32 and two shoulders 36, as shown in FIG. The two storage grooves 31 are formed at both front and rear ends of the inner peripheral surface of the nut 30.
The inner thread 32 is formed between the storage grooves 31 at the front and rear ends of the inner peripheral surface of the nut 30, and has two invalid tooth areas 33, that is, an area that does not mesh with the roller 60 (see FIG. 7) and one effective. It has a tooth area 34, that is, an area that meshes with the roller 60 (see FIG. 7) (see FIG. 7). Each of the two invalid tooth areas 33 is adjacent to the storage groove 31 and has a concave positioning portion 35 (see FIGS. 6 and 7). The two shoulders 36 are each formed on the inner peripheral surface of the nut 30 and are adjacent to the ineffective tooth area 33 of the storage groove 31 and the inner thread 32.

The two reflux units 40 have an annular portion 41, an induction portion 42, and a convex positioning portion 43, respectively. The guide portion 42 is formed so as to project from the inner side surface 412 of the annular portion 41 along the axial direction of the annular portion 41. The convex positioning portion 43 is formed so as to project from the outer surface of the guide portion 42 along the radial direction of the annular portion 41.
As shown in FIG. 4, after mounting the two reflux units 40 on the nut 30, the annular portion 41 of the two reflux units 40 is stored in the two storage grooves 31 of the nut 30. The inner surface 412 of the annular portion 41 of the two reflux units 40 abuts on the shoulder portion 36 of the nut 30. The induction portions 42 of the two reflux units 40 are located in the two invalid tooth areas 33 of the inner thread 32 of the nut 30. The convex positioning portions 43 of the two reflux units 40 are fitted into the two concave positioning portions 35 of the nut 30.
As shown in FIG. 8, since the axial length L2 of the convex positioning portion 43 is smaller than the axial length L1 of the concave positioning portion 35, the inner side surfaces 412 of the two reflux units 40 are attached to the shoulder portion 36 of the nut 30. It can be reliably abutted and a stopper function can be generated when the two reflux units 40 are mounted.

As shown in FIGS. 2 to 4, the nut 30 has separate radial screw holes 37 at both ends. The annular portion 41 of the two reflux units 40 has a positioning groove 44 on the outer peripheral surface. The two set screws 45 are tightened into the radial screw holes 37 of the nut 30. The end portion 452 of the two set screws 45 fits into the positioning groove 44 of the annular portion 41 of the two reflux units 40.
Due to the structural features described above, the two reflux units 40 can be controlled with respect to the nut 30 and moved along the axial direction. Further, since the width W of the positioning groove 44 is larger than the outer diameter R of the end portion 452 of the set screw 45, as shown in FIG. 4, the reflux unit 40 is pushed by the set screw 45 and is not damaged or deformed.

As shown in FIG. 2, the convex positioning portion 43 is semicircular, but is not limited to this. As shown in FIG. 10, the convex positioning portion 43 may be triangular. As shown in FIG. 11, the convex positioning portion 43 may be a quadrilateral. It suffices as long as a positioning effect can be produced between the concave positioning portion 35 of the nut 30 and the convex positioning portion 43.

As shown in FIGS. 2 and 5, the holder 50 is mounted between the screw shaft 20 and the nut 30 and has a plurality of holding grooves 52. The plurality of holding grooves 52 are arranged in an annular shape at an equal angle with respect to the axial direction of the screw shaft 20. In this embodiment, the holding grooves 52 and the rollers 60 correspond to each other, and the number is eight.

Each of the plurality of rollers 60 is mounted in the holding groove 52 of the holder 50, and each has a plurality of annular grooves 62. The plurality of annular grooves 62 are distributed on the outer peripheral surface of the roller 60 and are arranged at regular intervals along the axial direction. As shown in FIG. 4, the plurality of rollers 60 are meshed with the outer thread 22 of the screw shaft 20 and the effective tooth area 34 of the inner thread 32 of the nut 30 at the same time by the annular groove 62, respectively.
Due to the characteristics of the structure described above, when the screw shaft 20 rotates, the plurality of rollers 60 rotate and the holder 50 is synchronously rotated along the axial direction of the screw shaft 20, as shown in FIG. The induction portion 42 of the recirculation unit 40 pushes out all the rollers 60 and operates them alternately and continuously in the front-rear direction along the axial direction of the screw shaft 20.

Summarizing the features of the above-mentioned structure, the circulation type planetary roller screw 10 according to the present invention is recirculated with the nut 30 by the concave positioning portion 35 of the invalid tooth area 33 of the inner thread 32 and the convex positioning portion 43 of the recirculation unit 40. Since the units 40 are combined together, not only can the combination work of the reflux unit 40 and the nut 30 be simplified without limiting the outer diameter and length of the nut 30, but also the reflux unit 40 can be quickly removed for maintenance and use. The above convenience can be improved.

10 Circulating planetary roller screw 20 Thread shaft 22 Outer thread 30 Nut 31 Storage groove 32 Inner thread 33 Invalid tooth area 34 Effective tooth area 35 Concave positioning part 36 Shoulder part 37 Radial screw hole 40 Recirculation unit 41 Ring part 412 Inner surface 42 Guide part 43 Convex positioning part 44 Positioning groove 45 Set screw 452 Set screw end part 50 Holder 52 Holding groove 60 Roller 62 Ring groove L1 Axial length of concave positioning part L2 Convex positioning part Axial length R Outer diameter of the end of the set screw W Width of the positioning groove

Claims (5)

Equipped with screw shaft, nut, two reflux units, holder and multiple rollers,
The screw shaft has an outer thread on the outer peripheral surface and has an outer thread.
The nut is mounted on the screw shaft so that it can move along the axial direction of the screw shaft, has a storage groove and an inner thread, and the storage groove is separately formed at both ends of the inner peripheral surface of the nut. , The inner thread is formed on the inner peripheral surface of the nut and has two invalid tooth areas and one effective tooth area, each of which is adjacent to the storage groove. And has a concave positioning part,
The two reflux units are mounted on both ends of the nut and have an annular portion, a guide portion and a convex positioning portion, respectively, the annular portion is located in the storage groove of the nut, and the guide portion is the annular portion. Protruding on one side of the portion and located in the invalid tooth area of the inner thread, the convex positioning portion projects on the outer surface of the guide portion and fits into the concave positioning portion of the nut.
The holder is mounted between the screw shaft and the nut, has a plurality of holding grooves, and the plurality of holding grooves are arranged in an annular shape at an equal angle with respect to the axial direction of the screw shaft.
The plurality of rollers are separately mounted in the holding grooves of the holder, each having a plurality of annular grooves on the outer peripheral surface, and the plurality of the annular grooves are arranged at regular intervals along the axial direction of the rollers.
The plurality of annular grooves of each of the rollers mesh with the effective tooth area of the outer thread of the screw shaft and the inner thread of the nut at the same time, so that the plurality of rollers drive the screw shaft. When the holder is interlocked by a force and synchronously rotated along the axial direction of the screw shaft, the guiding portions of the two recirculation units push out a plurality of the rollers and reciprocate along the axial direction of the screw shaft. Characterized by letting
Circulating planetary roller screw. The nut has separate radial screw holes at both ends, the annular portion of the two recirculation units has a positioning groove on the outer peripheral surface, the set screw is tightened in the radial screw hole, and the end portion is The circulating planetary roller screw according to claim 1, wherein the screw is fitted into the positioning groove. The circulating planetary roller screw according to claim 2, wherein the width of the positioning groove is larger than the outer diameter of the end portion of the set screw. The nut has two shoulders on its inner peripheral surface, the two shoulders adjacent to the containment groove and the invalid tooth area of the inner thread, respectively, and the annular portion of the two reflux units. Each has an inner surface, the two recirculation units each abut against the shoulder of the nut by the inner surface of the annular portion, and the induction portions of the two recirculation units are each in the inner surface of the annular portion. The circulating planetary roller screw according to any one of claims 1 to 3, wherein the annular portion projects from the side surface along the axial direction of the annular portion. The circulating planetary roller screw according to claim 4, wherein the axial length of the concave positioning portion is larger than the axial length of the convex positioning portion.

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