JP2009115146A - Roller screw and roller circulation method for the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a roller screw that prevents a roller, moving from an unloaded return path to a loaded roller rolling path, from tilting. <P>SOLUTION: The roller screw has a screw shaft 1 having a helical roller rolling surface 1a on its outer peripheral surface, a nut 2 having a loaded roller rolling surface 2a on its inner peripheral surface, a circulation member 3 having an unloaded return path for connecting one end and the other end of the loaded roller rolling surface 2a of the nut 2, and a plurality of rollers 4 arranged on a loaded roller rolling path 6 and the unloaded return path. The circulation member 3 includes a scooping-up section 14 projecting toward the screw shaft 1 side so as to scoop up the roller 4, moving on the loaded roller rolling path 6, into the unloaded return path. The advancing direction in the unloaded return path of the roller 4 moving from the loaded roller rolling path 6 to the unloaded return path is more externally directed than the tangent direction of the loaded roller rolling path 6 when viewed from the axial direction of the nut 2. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a roller screw in which a roller is interposed between a screw shaft and a nut so as to allow rolling motion.

  In recent years, a roller screw has been developed in which a roller is interposed between a screw shaft and a nut so as to allow rolling motion. Since the roller and the roller rolling surface are in line contact, the roller screw has an advantage that the load that can be applied is larger than that of the ball screw. However, as compared with a ball that can roll in any direction in all directions, there is a problem that it is extremely difficult to circulate the roller because the traveling direction of the roller is limited to one direction.

  The circulation path of the roller screw is a spiral load roller rolling path formed between a spiral roller rolling surface on the outer peripheral surface of the screw shaft and a spiral load roller rolling surface on the inner peripheral surface of the nut. The load roller rolling path is composed of a no-load return path that connects one end and the other end. The no-load return passage is formed in the circulation member attached to the nut.

The roller moving along the spiral loaded roller rolling path is lifted up by the lifting portion of the circulation member and guided into the no-load return passage. In the conventional roller screw, in order to smoothly lift up the roller moving on the loaded roller rolling path, the no-load return path in which the lifting portion is formed is arranged in the tangential direction of the loaded roller rolling path (for example, Patent Document 1). That is, they are arranged in the tangential direction of the annular load roller rolling path as viewed from the axial direction of the nut and in the lead angle direction of the load roller rolling path as viewed from the side surface direction of the nut.
JP-A-11-210858

  However, as shown in FIG. 17, if the no-load return path is arranged in the tangential direction of the load roller rolling path, the lifting portion 32 of the circulation member 31 cannot be brought close to the load roller rolling path 33. This is because if the thickness is too close, it is impossible to secure a thickness sufficient to provide sufficient strength in order to prevent the raised portion 32 from coming into contact with the screw shaft. For this reason, an unconstrained section is generated before the roller 34 exits from the load roller rolling path 33 and is restrained by the lifting portion 32. Then, the roller tilts in this unconstrained section, and the axial end of the side surface of the roller 34 may collide with the edge of the lifting portion 32 as shown in FIG. The roller 34 that shifts from the loaded roller rolling path to the no-load return path enters the lifting portion while being pushed by the subsequent roller 34. If the roller 34 collides with the edge of the lifting portion 32, the edge of the lifting portion 32 may be damaged or the roller 34 may be clogged.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a roller screw that can prevent a roller that moves from a no-load return path to a loaded roller rolling path from being inclined, and a roller screw roller circulation method that can move smoothly.

The present invention will be described below.
In order to solve the above-mentioned problem, the invention of claim 1 includes a screw shaft having a spiral roller rolling surface on the outer peripheral surface, and a loaded roller rolling on the inner peripheral surface facing the roller rolling surface of the screw shaft. A nut having a surface, a circulating member provided on the nut and having a no-load return passage connecting one end and the other end of the loaded roller rolling surface of the nut, the roller rolling surface of the screw shaft, and the A plurality of rollers arranged in a loaded roller rolling path between the nut and the loaded roller rolling surface, a no-load return path of the circulation member, and the roller moving in the loaded roller rolling path, the unloaded A roller that moves up from the loaded roller rolling path to the no-load return path as viewed from the axial direction of the nut. Of the above The traveling direction in the road is a roller screw directed outward from the tangential direction of the loaded roller rolling path.

  The invention according to claim 2 is a screw shaft having a spiral roller rolling surface on the outer peripheral surface, and a nut having a load roller rolling surface facing the roller rolling surface of the screw shaft on the inner peripheral surface. A circulating member provided on the nut and having a no-load return passage connecting one end and the other end of the load roller rolling surface of the nut, the roller rolling surface of the screw shaft, and the load roller of the nut A plurality of rollers arranged in a loaded roller rolling path between the rolling surfaces and a no-load return path of the circulation member, and the roller moving in the loaded roller rolling path are crazed into the no-load return path. A hoisting path of the no-load return passage in which the hoisting part to be raised is formed, and when viewed from the axial direction of the nut, the center line of the hoisting path is outside the tangential direction of the load roller rolling path Roller screw .

  According to a third aspect of the present invention, in the roller screw according to the first or second aspect, the no-load return passage of the circulation member includes a straight passage extending parallel to the axis of the nut, and both ends of the straight passage. And a direction changing path having the hoisting path, and the center line of the hoisting path of the direction changing path is tangent to the center line of the load roller rolling path as viewed from the axial direction of the nut. The direction change path is bent on the way to the straight path so that the direction can be connected to the straight path while being directed outward from the direction.

  The invention according to claim 4 is a screw shaft having a spiral roller rolling surface on the outer peripheral surface, and a nut having a load roller rolling surface facing the roller rolling surface of the screw shaft on the inner peripheral surface. A circulating member provided on the nut and having a no-load return passage connecting one end and the other end of the load roller rolling surface of the nut, the roller rolling surface of the screw shaft, and the load roller of the nut A plurality of rollers arranged in a loaded roller rolling path between the rolling surfaces and a no-load return path of the circulation member, and the roller moving in the loaded roller rolling path are crazed into the no-load return path. And a roller screw that covers the roller when the center of the roller is located at a point where the center of the roller moves from the loaded roller rolling path to the no-load return path. is there.

  The invention according to claim 5 is a screw shaft having a spiral roller rolling surface on the outer peripheral surface, and a nut having a load roller rolling surface facing the roller rolling surface of the screw shaft on the inner peripheral surface. A circulating member provided on the nut and having a no-load return passage connecting one end and the other end of the load roller rolling surface of the nut, the roller rolling surface of the screw shaft, and the load roller of the nut A plurality of rollers arranged in a loaded roller rolling path between the rolling surfaces and a no-load return path of the circulation member, and the roller moving in the loaded roller rolling path are crazed into the no-load return path. A lifting portion of the circulating member to be raised, and the distance from the boundary between the loaded roller rolling path and the no-load return passage to the lifting portion when viewed from the axial direction of the nut is greater than the radius of the roller With a small roller screw That.

  According to a sixth aspect of the present invention, in the roller screw according to the fourth or fifth aspect, the no-load return passage has a hoisting path in which the hoisting portion is formed, and the load roller rolling path is used to The traveling direction of the roller moving to the no-load return path in the lifting path is directed outward from the tangential direction of the loaded roller rolling path as viewed from the axial direction of the nut.

  According to a seventh aspect of the present invention, in the roller screw according to any one of the first to sixth aspects, the end surface of the roller is a spherical surface.

  The invention according to claim 8 is the roller screw according to any one of claims 1 to 7, wherein the plurality of rollers are arranged in parallel so that axes of adjacent rollers are substantially parallel, Is formed of a mountain-shaped lip portion protruding to the screw shaft side and having a first wall portion corresponding to the end surface side of the roller and a second wall portion corresponding to the side surface of the roller, The edge of the second wall portion is the first wall so that the second wall portion can restrain the roller moving from the loaded roller rolling path to the no-load return passage. It is characterized by being closer to the load roller rolling path than the edge of the wall portion.

  According to a ninth aspect of the present invention, there is provided a roller that moves on a load roller rolling path between a spiral roller rolling surface on the outer peripheral surface of the screw shaft and a spiral load roller rolling surface on the inner peripheral surface of the nut. In the method of circulating a roller screw of a roller screw that is lifted up by a lifting portion of a circulating member provided on the nut and guided to a no-load return passage formed in the circulating member, the center of the roller extends from the loaded roller rolling path. The roller screw roller circulation method according to claim 1, wherein when the roller is located at a point where the unloaded return path is moved, the roller raising portion of the circulation member covers the roller.

  According to the first aspect of the present invention, since the moving direction of the roller in the hoisting path faces the outside of the tangential direction of the load roller rolling path, the edge of the hoisting part is secured to the load roller after ensuring the thickness of the hoisting part. Can approach the rolling path. Since the section in which the roller is restrained by the lifting portion can be lengthened and the unconstrained section can be shortened, the roller can be prevented from tilting.

  According to the second aspect of the present invention, since the moving direction of the roller in the hoisting path is outside the tangential direction of the load roller rolling path, the edge of the hoisting section is secured to the load roller rolling path after ensuring the thickness of the hoisting section. Can be approached. Since the section in which the roller is restrained by the lifting portion can be lengthened and the unconstrained section can be shortened, the roller can be prevented from tilting.

  According to the third aspect of the present invention, it is possible to connect the lifting path and the straight path from the tangential direction to the outside.

  According to the fourth aspect of the present invention, the end portion in the moving direction of the roller enters the lifting portion of the circulation member before the roller completely comes out of the loaded roller rolling path. For this reason, it is possible to eliminate a section where the roller is unconstrained.

  According to the fifth aspect of the present invention, the end portion in the moving direction of the roller enters the lifting portion of the circulation member before the roller completely comes out of the loaded roller rolling path. For this reason, it is possible to eliminate a section where the roller is unconstrained.

  According to the sixth aspect of the present invention, since the traveling direction of the roller in the no-load return path is outside the tangential direction of the loaded roller rolling path, the edge of the lifting portion is loaded after securing the thickness of the lifting portion. Can approach the roller rolling path.

  According to the seventh aspect of the present invention, when the roller enters the lifting portion of the circulation member, the end surface of the roller is not caught by the edge of the lifting portion. Further, even when the roller passes through the step between the parts, the end surface of the roller is not caught by the step.

  According to the eighth aspect of the present invention, since the side surface side of the roller is first restrained by the lip portion, it is possible to prevent the end surface side of the roller from coming into contact with the edge of the lip portion and damage the lip portion. .

  According to the ninth aspect of the present invention, immediately before the roller exits the loaded roller rolling path, the end portion in the moving direction of the roller enters the raised portion of the circulation member. For this reason, it is possible to eliminate a section where the roller is unconstrained.

  FIG.1 and FIG.2 shows the perspective view of the roller screw in one Embodiment of this invention. FIG. 1 is a perspective view (including a partial cross-sectional view) of a roller screw.

  The roller screw includes a screw shaft 1 having a spiral roller rolling surface 1a formed on the outer peripheral surface, and a nut having a spiral load roller rolling surface 2a facing the roller rolling surface 1a on the inner peripheral surface. 2 is provided.

  The screw shaft 1 is formed by cutting and grinding or rolling a spiral roller rolling surface 1a having a predetermined lead on the outer peripheral surface of a steel bar such as carbon steel, chrome steel, or stainless steel. . The roller rolling surface 1a has a V-shaped cross section and an opening angle of about 90 degrees. In this embodiment, two roller rolling surfaces 1 a are formed on the outer peripheral surface of the screw shaft 1. A plurality of rollers are arranged in parallel on each of the two roller rolling surfaces 1a. The axes of the plurality of rollers arranged in parallel on the two roller rolling surfaces 1a face in opposite directions. This is because a load in two opposite directions in the axial direction of the screw shaft 1 is applied. In order to circulate the rollers moving on the two roller rolling surfaces 1a, two sets of circulation members 3 are provided. Of course, the number of roller screws is appropriately determined depending on the application of the roller screw, such as one, two or three.

  FIG. 2 shows a perspective view of the nut 2. The nut 2 is formed by cutting and grinding or rolling a spiral load roller rolling surface 2a having a predetermined lead on the inner peripheral surface of a cylinder such as carbon steel, chrome steel, or stainless steel. is there. The load roller rolling surface 2a has a V-shaped cross section and an opening angle of about 90 degrees. A flange 2b for attaching the nut 2 to the mating part is formed at the end of the outer periphery of the nut 2 in the axial direction.

  FIG. 3 shows the roller 4 sandwiched between the roller rolling surface 1 a of the screw shaft 1 and the load roller rolling surface 2 a of the nut 2. The roller 4 is cylindrical and has substantially the same diameter and length. The shape of the roller 4 viewed from the side is close to a square. The end surface 4 a of the roller 4 is chamfered in a spherical shape with a constant curvature radius R. Since the end surface 4a is a spherical surface, the end surface 4a of the roller 4 contacts the roller rolling surface 1a at one point. As described above, each of the two load roller rolling paths 6 is arranged in parallel so that the axes of the adjacent rollers 4 are substantially parallel. A retainer (not shown) is interposed between the adjacent rollers 4. The retainer holds the posture of the roller 4 so that the axis of the roller 4 passes through the center line of the screw shaft 1.

  The roller 4 applies a load on its side surface 4c that contacts the roller rolling surface 1a of the screw shaft 1 and the loaded roller rolling surface 2a of the nut 2, but does not load the end surface 4a. For this reason, each roller 4 can only apply a load in one direction in the axial direction of the screw shaft 1. By making the direction of the axis 4b of the plurality of rollers 4 arranged in parallel different from each other in the two load roller rolling paths 6, it is possible to load loads in two opposite directions ((1) and (2) directions). .

  4 and 5 show the circulation member 3 attached to the nut 2. The circulation member 3 includes a circulation pipe 8 that is inserted into a through-hole extending in the axial direction of the nut 2, and a pair of direction change path constituting members 12 that are attached to end portions in the axial direction of the circulation pipe 8. The circulation member 3 is formed with a no-load return path that connects one end and the other end of the load roller rolling path 6. The no-load return passage is connected to both ends of the straight passage 9 (see FIG. 5) linearly extending in parallel with the center line of the nut 2 and curves formed in the pair of direction change path constituent members 12. And a pair of direction change paths. The roller 4 that has rolled to one end of the load roller rolling path 6 is guided into the direction changing path of the circulation member 3, passes through the straight path 9, and then again passes from the remaining direction changing path to the other end of the load roller rolling path 6. Returned.

  The circulation pipe 8 is formed by joining two divided pieces 8a and 8b. FIG. 5 shows a state where one divided piece 8b is removed. Inside the circulation pipe 8, a straight passage 9 extending linearly in parallel with the axial direction of the nut 2 is formed. The straight passage 9 is twisted so that the posture of the roller 4 moving in the straight passage 9 can be rotated. By rotating the posture of the roller in the linear passage 9, the roller 4 that has been scooped up from one end of the load roller rolling path 6 can be returned in a state in which the posture is matched with the other end of the load roller rolling path 6.

  The mating surfaces of the divided pieces 8a and 8b are on the diagonal line of the straight passage 9 having a square cross section. Since the straight passage 9 is twisted, the mating surfaces 16 of the divided pieces 8a and 8b are also twisted. In the middle of the circulation pipe 8 in the axial direction, the apex of the quadrangle serving as the mating surface 16 is switched. This is to prevent an undercut from occurring when the straight passage 9 twisted in the divided pieces 8a and 8b is processed. Positioning holes for positioning the circulation pipe 8 are formed in both end faces of the circulation pipe 8 in the axial direction.

  The direction change path component 12 is attached to the end surface of the nut 2. FIG. 6 shows a perspective view of the direction change path constituting member 12. The direction change path constituting member 12 is formed by combining an R piece 10 constituting the inner peripheral side of the direction change path and an end piece 11 constituting the outer peripheral side of the direction change path 7.

  The direction change path constituting member 12 protrudes toward the roller rolling surface 1a having a V-shaped cross section of the screw shaft 1 and moves up the roller 4 moving on the load roller rolling path 6 into the direction changing path. As shown, a V-shaped mountain-shaped lip portion 14 is provided. When the direction change path component 12 is attached to the nut 2, the edge 14 a of the lip portion 14 is close to the roller rolling surface 1 a having a V-shaped cross section of the screw shaft 1. An end 7e of the direction change path 7 opposite to the lip 14 is continuous with the load roller rolling surface 2a of the nut 2 having a V-shaped cross section. A positioning hole 15 is machined in the joint surface 12a of the direction change path constituting member 12 with the circulation pipe 8. By positioning positioning pins into the positioning holes 15 of the circulation pipe 8 and the direction change path constituting member 12, these positioning can be performed.

  FIG. 7 is a perspective view of the R piece 10, and FIG. 8 is a perspective view of the end piece 11. The direction change path 7 is curved, but not twisted. The direction change path component 12 is divided into an inner peripheral R piece 10 and an outer end end piece 11 along a diagonal line of the direction change path 7 having a quadrangular cross section. As shown in FIG. 7, the R piece 10 includes a flange portion 10 a attached to the end surface of the nut 2 and a main body portion 10 b in which the direction change path 7 is formed. A mounting hole 17 for mounting the R piece 10 to the nut 2 is processed in the flange portion 10a. A half of the lip portion 14 that scoops up the roller 4 moving on the load roller rolling path 6 is formed in the portion where the direction changing path 7 of the flange portion 10a is formed. The R piece 10 may be manufactured by cutting a metal, or may be a resin molded product.

  As shown in FIG. 8, the end piece 11 includes a flange portion 11 a attached to the end surface of the nut 2 and a main body portion 11 b in which the direction change path 7 is formed. A half of the lip portion 14 that scoops up the roller 4 moving on the load roller rolling path 6 is formed in the portion where the direction change path 7 of the flange portion 11a is formed. The end piece 11 may be manufactured by cutting a metal, or may be a resin molded product.

  As shown in FIG. 9, the R piece 10 and the end piece 11 are overlapped, a bolt (not shown) is passed through these flange portions 10 a, 11 a, and the bolt is screwed into the end face of the nut 2, thereby Can be attached to the nut 2. When the direction change path constituting member 12 is attached to the nut, the lip portion 14 enters inside the thread 1c of the roller rolling surface 1a of the screw shaft 1, but contacts the screw bottom 1d of the roller rolling surface 1a. There is nothing.

  FIG. 10 shows the structure of the direction change path 7 as seen from the axial direction of the screw shaft 1. FIG. 10 shows a state where the end piece 11 is removed. A two-dot chain line in the figure indicates the center line 7 a of the direction change path 7, and a broken line in the figure indicates the tangential direction 6 a of the load roller rolling path 6. The direction change path 7 has a lifting path 7b in which the lip portion 14 is formed. At the connection point between the loaded roller rolling path 6 and the no-load return path, the center line 7a of the lifting path 7b connected to the loaded roller rolling path 6 is outside the tangential direction 6a of the center line 6b of the loaded roller rolling path 6. I.e., inside the nut 2. In other words, the advancing direction of the roller 4 moving from the load roller rolling path 6 to the lifting path 7 b in the lifting path 7 b is more outward than the tangential direction of the load roller rolling path 6. Then, the direction changing path 7 bends in an arc shape on the way to the straight path 9 so that the lifting path 7 b can be connected to the straight path 9, and is connected to the end of the straight path 9. After designing the center line 7a of the direction change path 7 as described above, the direction change path 7 can be designed by moving the roller 4 along the center line 7a. The center line 7 a of the direction change path 7 viewed from the side surface direction of the screw shaft 1 faces the lead direction of the screw shaft 1.

  The advancing direction of the roller 4 in the hoisting path 7b is directed to the outside of the tangential direction 6a, thereby ensuring the thickness of the lip part 14 and extending the edge 14a of the lip part 14 toward the loaded roller rolling path 6. be able to. Thereby, since the unconstrained area until the roller 4 enters into the lip | rip part 14 from the load roller rolling path 6 becomes short, it can prevent that the roller 4 inclines in an unconstrained area.

  FIG. 11 shows the path of the roller 4 that is scooped up by the lip portion 14. In the loaded roller rolling path 6, the roller 4 rolls while making line contact with the roller rolling surface 1 a of the screw shaft 1 and the loaded roller rolling surface 2 a of the nut 2. The roller 4 that has moved to the end of the loaded roller rolling path 6 enters the lip portion 14. Here, immediately before the roller 4 exits from the loaded roller rolling path 6, the end in the traveling direction enters the lip portion 14. More precisely, as shown in FIG. 12, when the center 4 d of the roller 4 is located at a point where the load roller rolling path 6 moves to the no-load return path, the edge 14 a of the lip portion 14 moves in the direction of travel of the roller 4. Cover the end of the. In other words, the distance from the boundary 20 between the loaded roller rolling path 6 and the unloaded return path to the lip portion 14 is smaller than the radius of the roller 4. An angle α (see FIG. 10) between the center line 7 a of the lifting path 7 b and the tangential direction 6 a (see FIG. 10) is set so that the edge 14 a of the lip 14 covers the end of the roller 4 in the traveling direction.

  As shown in FIG. 12, the roller 4 enters the lip portion 14 while maintaining the posture when positioned in the loaded roller rolling path 6. For this reason, it can prevent that the roller 4 which transfers into the lip | rip part 14 from the load roller rolling path 6 inclines. When the roller 4 enters the lip portion 14, the edge 14a of the lip portion 14 and the roller 4 do not come into contact with each other, so that the edge 14a of the lip portion 14 is not damaged. When the roller 4 further enters the lip portion 14, the inner wall surface of the lip portion 14 contacts the side surface of the roller 4 to guide the roller 4 into the direction change path 7.

  13 and 14 show the direction change path 7 formed in the R piece 10 and the end piece 11. The direction change path 7 of the R piece 10 and the end piece 11 connects the lifting path 7 b facing outward from the tangential direction of the direction change path 7, the bent intermediate path 7 c, the intermediate path 7 c, and the straight path 9. A communication path 7d.

  FIG. 15 shows a side view of the roller 4 moving along the circulation path. In the figure, (A) is a roller 4 having a spherical end surface, and (B) in the figure shows a roller 21 in which an end surface 21a is chamfered in an arc shape. When the roller 21 was circulated using the roller 21 having an R shape on the end face, the restraint of the roller 21 at the edge 14a of the lip portion 14 was large. By making the end surface of the roller 4 spherical, the roller 4 could be smoothly moved for the first time. Further, when the end surface 4a of the roller 4 is formed into a spherical surface, the radius of curvature of the end surface 4a can be increased as compared with the case where arc-shaped chamfering is performed. For this reason, also when passing the level | step difference between components, the inclination of the tangential direction 4e of the part which hits the level | step difference of the end surface 4a becomes loose. Therefore, it becomes difficult for the roller 4 to be caught by the step. If the end surface 4a of the roller 4 is a spherical surface, the roller 4 is likely to be inclined. Therefore, it is desirable to interpose a retainer for preventing the inclination between the adjacent rollers 4.

  FIG. 16 shows another example of the lip portion 14. The lip portion 14 has a mountain shape in which the first wall portion 26b and the second wall portion 26a are combined at the apex 26c. The first wall portion 26 b is located on the end surface side of the roller 4, and the second wall portion 26 a is located on the side surface side of the roller 4. The first wall portion 26b is cut short. The edge 28b of the first wall portion 26b is displaced from the edge 28a of the second wall portion 26a with the vertex 26c as a boundary, and is further away from the load roller rolling path 6 than the edge 28a of the second wall portion 26a. Thus, by making the lengths of the lip portions 14 on the end surface side and the side surface side of the roller 4 different, the side surface of the roller 4 can be constrained first, and then the end surface of the roller 4 can be constrained. If the end surface of the roller 4 comes into contact with the lip portion 14 first, the lip portion 14 may be damaged. By constraining the side surface of the roller 4 first and keeping the angle of the end surface of the roller 4 constant, the end surface of the roller 4 is constrained to prevent the lip portion 14 from being damaged.

  In addition, this invention is not restricted to the said embodiment, In the range which does not change the summary of this invention, it can change variously. For example, in addition to the lip portion that protrudes toward the screw shaft as described above, a boat bottom scooping portion that scoops the diagonal line of the roller, such as a ball screw boat scooping, may be adopted as the boat lifting portion. Good. The rollers may be arranged in parallel so that the axes of adjacent rollers are parallel, or may be arranged in a cross manner so as to be orthogonal. A tapered roller having a tapered side surface may be used instead of the cylindrical roller. The circulation member is not limited to the end cap type circulation member as in this embodiment, and may be a return pipe in which both ends of the pipe are bent.

The perspective view of the roller screw in one Embodiment of this invention Perspective view of the roller screw nut Side view showing a roller sandwiched between a screw shaft and a nut Perspective view of circulation member Perspective view of the circulation member (with the split piece removed) Perspective view of direction change path components R piece perspective view End piece perspective view The figure which shows R piece and end piece attached to the nut The figure which shows the structure of the direction change path seen from the axial direction of the screw shaft Perspective view showing roller lifting at the lip Schematic diagram showing roller lifting at the lip (viewed from the axial direction of the screw shaft) The figure which shows the direction change path formed in R piece The figure which shows the direction change path formed in the end piece Schematic diagram showing a roller that moves on a step ((A) in the figure shows a roller with a spherical end surface, and (B) shows a roller with an R-shaped end surface) The perspective view which shows the other example of a raising part The figure which shows the raising of the circulation member seen from the axial direction of the screw shaft (conventional example) Schematic diagram showing contact between roller and roller (conventional example)

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Screw shaft 1a ... Roller rolling surface 2 ... Nut 2a ... Load roller rolling surface 3 ... Circulating member 4 ... Roller 4a ... End surface 6a ... Tangent direction 6 of load roller rolling path ... Load roller rolling path 7 ... Direction change path 7a ... Center line 7b of the direction change path ... Raised path 10 ... R piece 11 ... End piece 12 ... Direction change path component 14 ... Lip part (raised part)
14a ... Edge

Claims (9)

A screw shaft having a spiral roller rolling surface on the outer peripheral surface;
A nut having a load roller rolling surface opposed to the roller rolling surface of the screw shaft on the inner peripheral surface;
A circulating member provided on the nut and having a no-load return passage connecting one end and the other end of the load roller rolling surface of the nut;
A plurality of rollers arranged in a loaded roller rolling path between the roller rolling surface of the screw shaft and the loaded roller rolling surface of the nut, and a no-load return path of the circulation member;
A hoisting path of the no-load return path in which a hoisting part that scoops up the roller moving on the loaded roller rolling path into the no-load return path is provided,
A roller whose traveling direction in the lifting path of the roller that moves from the loaded roller rolling path to the no-load return path is directed outward from the tangential direction of the loaded roller rolling path as viewed from the axial direction of the nut. screw. A screw shaft having a spiral roller rolling surface on the outer peripheral surface;
A nut having a load roller rolling surface opposed to the roller rolling surface of the screw shaft on the inner peripheral surface;
A circulating member provided on the nut and having a no-load return passage connecting one end and the other end of the load roller rolling surface of the nut;
A plurality of rollers arranged in a loaded roller rolling path between the roller rolling surface of the screw shaft and the loaded roller rolling surface of the nut, and a no-load return path of the circulation member;
A hoisting path of the no-load return path in which a hoisting part that scoops up the roller moving on the loaded roller rolling path into the no-load return path is provided,
A roller screw in which a center line of the lifting path is directed outward from a tangential direction of the load roller rolling path when viewed from the axial direction of the nut. The no-load return passage of the circulation member has a straight passage extending in parallel with the axis of the nut, and a direction changing passage provided at both ends of the straight passage and having the lifting path.
When viewed from the axial direction of the nut, the center line of the lifting path of the direction changing path is directed outward from the tangential direction of the center line of the load roller rolling path, and the lifting path is used as the straight path. 3. The roller screw according to claim 1, wherein the direction changing path is bent in the middle of reaching the straight path so as to be connected. 4. A screw shaft having a spiral roller rolling surface on the outer peripheral surface;
A nut having a load roller rolling surface opposed to the roller rolling surface of the screw shaft on the inner peripheral surface;
A circulating member provided on the nut and having a no-load return passage connecting one end and the other end of the load roller rolling surface of the nut;
A plurality of rollers arranged in a loaded roller rolling path between the roller rolling surface of the screw shaft and the loaded roller rolling surface of the nut, and a no-load return path of the circulation member;
A scooping portion of the circulating member that scoops up the roller that moves on the load roller rolling path into the no-load return passage;
A roller screw that covers the roller when the center of the roller is located at a point where the center of the roller moves from the loaded roller rolling path to the unloaded return path. A screw shaft having a spiral roller rolling surface on the outer peripheral surface;
A nut having a load roller rolling surface opposed to the roller rolling surface of the screw shaft on the inner peripheral surface;
A circulating member provided on the nut and having a no-load return passage connecting one end and the other end of the load roller rolling surface of the nut;
A plurality of rollers arranged in a loaded roller rolling path between the roller rolling surface of the screw shaft and the loaded roller rolling surface of the nut, and a no-load return path of the circulation member;
A scooping portion of the circulating member that scoops up the roller that moves on the load roller rolling path into the no-load return passage;
A roller screw having a distance from the boundary between the loaded roller rolling path and the no-load return path to the raised portion when viewed from the axial direction of the nut is smaller than the radius of the roller. The no-load return passage has a lifting path in which the lifting portion is formed,
The advancing direction of the roller moving from the loaded roller rolling path to the no-load return path in the lifting path is directed outward from the tangential direction of the loaded roller rolling path as viewed from the axial direction of the nut. The roller screw according to claim 4 or 5.   The roller screw according to any one of claims 1 to 6, wherein an end surface of the roller is a spherical surface. The plurality of rollers are arranged in parallel so that the axes of adjacent rollers are substantially parallel,
The raised portion protrudes toward the screw shaft side, and has a mountain-shaped lip portion having a first wall portion corresponding to the end surface side of the roller and a second wall portion corresponding to the side surface of the roller. Consists of
The edge of the second wall portion is the first wall so that the second wall portion can restrain the roller moving from the loaded roller rolling path to the no-load return passage before the first wall portion. The roller screw according to claim 1, wherein the roller screw is closer to the loaded roller rolling path than an edge of the wall portion. A roller that moves on a load roller rolling path between a spiral roller rolling surface on the outer peripheral surface of the screw shaft and a spiral load roller rolling surface on the inner peripheral surface of the nut is provided on the circulating member provided on the nut. In the circulating method of the roller of the roller screw that is scooped up by the scooping portion and led to the no-load return passage formed in the circulating member,
When the center of the roller is located at a point where the load roller rolling path is shifted to the no-load return path, the roller screw roller circulating method covers the roller with the raised portion of the circulating member. .

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