JP3964008B2 - Tube type ball screw device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention is configured by screwing a screw shaft and a nut member through a large number of balls, and converting a rotary motion of a motor or the like into a linear motion and transmitting it in a slide portion of a machine tool, an industrial robot or the like The present invention relates to a screw device, and more particularly to a tube-type ball screw device having a ball circulation tubular body to form an endless track of a ball.
[0002]
[Prior art]
In general, a ball screw device includes a screw shaft having a spiral ball rolling groove on the outer peripheral surface, a spiral having the same lead angle as the ball rolling groove, opposite to the ball rolling groove on the inner peripheral surface. And a plurality of balls that are interposed between the load rolling grooves and the ball rolling grooves and roll while applying a load, and In order to circulate a large number of the balls, an endless track of the balls is formed.
[0003]
As a method of constructing the endless track of the ball, several methods have been conventionally known. For example, as shown in FIGS. 20 and 21, the ball rolling groove b of the screw shaft a and the nut member c are formed. A ball e that protrudes into the ball rolling groove b at both ends and rolls in the ball rolling groove b in the load area between the start and end of the load area formed by the load rolling groove d. A ball tube f having a tongue piece g for feeding the ball e into the ball rolling groove b in the load area is bridged, and the ball e exiting the end of the load area is again passed through the ball tube f. A tube system (Japanese Utility Model Laid-Open No. 49-64672) that circulates at the beginning of the load region is known.
[0004]
However, in this tube-type method, when the ball e moves from the end of the load region of the endless track to the no-load region, the ball e collides with the tongue piece g of the ball tube f, thereby causing no ball e to roll. It is scooped up into the ball tube f forming the load region and is circulated again to the start end of the load region.
[0005]
For this reason, in this conventional ball screw device, when the ball rolling in the load area is scooped up into the no-load area, or when the ball in this no-load area is fed into the load area, the traveling direction of the rolling ball The presence of a tongue piece g for changing the position of the ball screw is indispensable, and as a result, the smooth circulation movement of the ball is inevitably impaired. It also causes noise.
[0006]
Furthermore, in Japanese Utility Model Publication No. 5-27408, as shown in FIG. 22, a flexible belt-like retainer i is circulated in a circulation path h of a ball e provided with a ball circulation pipe (ball tube f). The belt h is slidably provided over the entire length of the path h, and a plurality of ball pockets (not shown) are provided at predetermined intervals over the entire length of the belt-like retainer i, and the ball e is placed in these ball pockets. Disclosed is a ball screw device that is held rotatably so that adjacent balls e do not come into contact with each other, have no rotational torque unevenness, have excellent operating characteristics, and can smoothly circulate in the circulation path h. ing.
[0007]
However, in such a ball screw device, the belt-like retainer i incorporated in the circulation path h of the ball e inevitably undergoes large twisting and bending, and the twisting and bending of the belt-like retainer i are circulated through the circulation path. It is necessary to absorb within h, and even if it is established as a concept that “a ball-shaped retainer incorporated in the circulation path prevents contact between adjacent balls and has excellent operation characteristics”, Actually, there is no appropriate means for how to absorb the twist and bending of the belt-like retainer i in the circulation path h, and the actual situation is that the product has not yet been completed as a product.
[0008]
[Problems to be solved by the invention]
Thus, as a result of intensive studies on means that can fundamentally solve this problem, the present inventors have determined that the ball connection body is formed using a flexible connection body that holds a large number of balls in an aligned state and is capable of rolling. In addition, a guide groove is formed in the endless track unloaded area consisting of the unloaded ball path to guide the connected body of the ball connected body. The connected body is moved and each ball is guided and moved by the connected body in the unloaded region of the endless track, and the traveling direction of the ball moving through the loaded rolling groove at least on the loaded rolling groove side of the unloaded ball path A guiding part that guides the connecting body along the rim is formed, thereby facilitating the transfer of the ball between the load area and the no-load area of the endless track, and smooth circulation of the ball in the endless track. Can achieve Heading the door, it has led to the completion of the present invention.
[0009]
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a tube-type ball screw device that can smoothly transfer and receive a ball between a load region and an unload region of an endless track, thereby achieving a smooth circulation movement of the ball. It is in.
[0010]
[Means for Solving the Problems]
That is, the present invention provides a screw shaft having a spiral ball rolling groove on the outer peripheral surface, and a nut member having a spiral load rolling groove facing the ball rolling groove of the screw shaft on the inner peripheral surface; A tubular body for ball circulation having an unloaded ball passage which is attached to the nut member and communicates the start and end of the load rolling groove to form an endless track of the ball, and a large number of rolling in the endless track In a tube-type ball screw device comprising a ball coupling body formed of a coupling body that holds these balls in an aligned state so as to be rotatable. Forms a guide groove that guides the connection body of the ball connection body, and moves the connection body with each ball in the load region of the endless track composed of the load rolling groove, and connects the connection body in the unloading region of the endless track. A tube-type ball in which a ball is guided and moved, and a guide portion is formed on at least the load rolling groove side of the no-load ball path to guide the connecting body along the traveling direction of the ball moving in the load rolling groove. It is a screw device.
[0011]
The present invention also includes a screw shaft having a spiral ball rolling groove on the outer peripheral surface and a spiral load rolling groove facing the ball rolling groove of the screw shaft on the inner peripheral surface. There is a no-load ball passage for circulating the ball from one end of the rolling groove to the other end, a nut member that is screwed to the screw shaft via a number of balls, and is attached to the nut member, and one end is No load that opens at the end of the load rolling groove and opens the other end at the start of the load rolling groove, and sends the ball coming out from the end of the load rolling groove to the start of the load rolling groove to circulate the ball A number of balls that roll in an endless track formed by a ball circulation tubular body that forms a ball passage, a load rolling groove of the nut member and an unloaded ball passage of the ball circulation tubular body, and these balls Flexible connectors that connect to each other in a chain In a tube-type ball screw device provided with a formed ball coupling body, an interposition part that interposes the coupling body of the ball coupling body between the balls and a coupling part that communicates and connects the interposition parts; The connection body holds a large number of balls in an aligned state so as to be rollable, and the ball circulation tubular body is formed of a pair of tube pieces and a tube body that connects the pair of tube pieces in communication with each other. Each pipe piece is provided with a guide hole having a guide region for guiding each ball in the tangential direction along the lead angle of the load rolling groove at least on the side of the load rolling groove. The connecting portion of the connecting body constituting the ball connecting body is slidably fitted in the communicating hole of the tube body that forms a no-load ball passage by connecting and connecting the guide holes of the piece and the guide holes. Guide the lever In a loaded rolling groove that forms a guide groove and constitutes a load area of an endless track, the unloaded ball that forms a no-load area of an endless track while moving the connected body by each ball rolling in the load rolling groove The passage is a tube-type ball screw device in which each ball is guided and moved by a connecting body that moves in the unloaded ball passage.
[0012]
In the present invention, the ball rolling groove formed on the outer peripheral surface of the screw shaft may be formed in a so-called circular shape having a substantially semi-circular ball rolling surface. It may be formed in a so-called Gothic arch shape in which approximately 1/4 circle arc-shaped ball rolling surfaces intersect, and the number may be one or more than two. Good.
[0013]
Further, the nut member screwed to the screw shaft through a large number of balls has a spiral load rolling groove opposite to the ball rolling groove of the screw shaft on the inner peripheral surface thereof. As with the ball rolling groove of the screw shaft, the load rolling groove may be formed in a so-called circular shape having a substantially semi-circular ball rolling surface, or two substantially It may be formed in the shape of a so-called Gothic arch where the arc-shaped ball rolling surfaces of ¼ circle intersect, and the number thereof is 2 even if the number is one corresponding to the number of ball rolling grooves. It may be a multiple number of lines.
[0014]
In the present invention, the ball circulation tubular body forming the unloaded ball path of the endless track is composed of a pair of tube pieces and a tube body that communicates and connects the pair of tube pieces. Has a guide hole having a guide region for guiding each ball in the tangential direction along the lead angle of the load rolling groove at least on the side of the load rolling groove, and further, guide holes of the pair of pipe pieces. In addition, a connecting portion of the connecting body constituting the ball connecting body is slidably fitted into the connecting hole of the tube body that forms a no-load ball passage by connecting and connecting the guide holes. Guide grooves are formed for guiding.
[0015]
And about each guide hole formed in the pair of pipe pieces, preferably, the guide groove at the load rolling groove side start end from the start end of the nut member on the load rolling groove side to the terminal end of the tube body on the communication hole side A tube body that is twisted and / or bent so that the positions of the strips are symmetric and the guide groove strips at the end of the communication hole side are the same, thereby connecting the pair of tube pieces in communication. Can be formed easily.
[0016]
Particularly preferably, each guide hole of the pair of tube pieces is formed in the guide region over the entire length thereof, and a part or all of the guide groove of each guide hole is imparted with a twist of its position. In the tube body that connects the pipe pieces in communication, the guide groove is formed at the same position from the start end to the end, and a bent portion is formed on the start end side and the end side, and a pair of pipe pieces is formed. Are formed in a completely same shape with a sintered body using a powder metal, and a tube body communicating and connecting between the pair of tube pieces is composed of a pair of tube pieces having the same shape. Thus, the number of molded parts can be reduced by configuring the ball circulation tubular body with a pair of tube pieces having the same shape and a pair of tube pieces having the same shape.
[0017]
Further, the shape of each tube piece is preferably formed in an outer contour shape such as an ellipse, a quadrangle, or a pentagon, and the nut member side corresponds to the outer contour shape of each tube piece. It is preferable that a non-circular fitting hole is formed and each pipe piece attached to the nut member is positioned by fitting the pipe piece into the fitting hole.
[0018]
In addition, each of these tube pieces may be formed as a whole as one part, or when divided into a plurality of parts and fitted in a fitting hole formed on the nut member side. The divided tube pieces may be combined to form one complete tube piece.
[0019]
Note that the method of connecting and connecting the pair of tube pieces and the tube body also includes the unloaded ball passage formed by each of the tube pieces and the tube body and the guide groove formed along the unloaded ball passage. However, the nut member is not particularly limited, but the nut member has a mounting surface for fixing the tube body on the outer peripheral surface and is drilled in the nut member. The depth of the fitting hole is deeper than the length dimension of each tube piece, and a positioning step for positioning the end of the tube body is formed on the upper surface of each tube piece. It is preferable to fix the both ends of the tube body to the mounting surface of the nut member by means such as a solid metal fitting.
[0020]
The twist and / or bending applied to the unloaded ball passage of the ball circulation tubular body composed of a pair of tube pieces and tube bodies may all be processed on the tube piece side. It is preferable that only the twist is applied to the side, and the bending is applied to the tube body side. In this way, it is preferable to disperse the twisting and / or bending process between the tube piece and the tube body, improve workability and make the molded parts common, reduce the number of parts, and reduce costs.
[0021]
For the ball assembly incorporated in the endless track of the ball, the balls are connected in a chain with the connection body so that the balls do not collide with each other. In order to prevent the balls from dropping off at least so that the balls can be guided and moved in the no-load area by moving the connected bodies with the balls, and in the no-load area, the balls can be guided and moved. And it is necessary to hold | maintain so that rolling is possible, and for that purpose, a connection body is comprised by the connection part which carries out the communication connection between these interposed parts and the interposed part interposed between each ball | bowl.
[0022]
The ball connection body may be incorporated into an endless track of a ball as one or a plurality of end ball connection bodies formed by a connection body having both ends, and one endless connection body. It may be incorporated in an endless track of the ball as an endless ball coupling body.
[0023]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below based on examples shown in the accompanying drawings.
[0024]
1 and 2 show a tube-type ball screw device of the present invention. This ball screw device is basically formed in a cylindrical shape having a screw shaft 1 having a single spiral ball rolling groove 5 on the outer peripheral surface and a through hole of the screw shaft 1 in the center. The inner peripheral surface has one spiral load rolling groove 6 opposite to the ball rolling groove 5 and a flat mounting surface 7 on the outer periphery, and is located at a diagonal position of the mounting surface 7. The nut member 2 has a pair of fitting holes 8 drilled from the mounting surface 7 toward the starting end and the terminal end of the load rolling groove 6, respectively, and is attached to the mounting surface 7 of the nut member 2 by a mounting bracket 9. A ball circulation tubular body 3 having a no-load ball passage 10 having an endless track formed by communicatively connecting the start end and the end of the load rolling groove 6 of the nut member 2, and the load of the nut member 2 The rolling groove 6 (load region) and the bolt attached to the nut member 2 It is comprised by the one end ball coupling body 4 which rolls in the endless track formed with the no-load ball channel | path 10 (no-load area | region) of the tubular body 3 for this circulation. The body 4 is formed by a large number of balls 11 and a flexible coupling body 12 which connects the large number of balls 11 to each other in a chain and is formed of a synthetic resin and has both ends. In FIG. 2, the end ball coupling body 4 is schematically drawn so that the twist of the coupling body 12 can be easily understood.
[0025]
In this embodiment, as shown in FIG. 3 to FIG. 5, the end ball coupling body 4 includes a coupling body 12 interposed between the balls 11 and vertically extending along the spherical surface of each ball 11. Two kinds of claw-like interposition parts 13a, 13b (13) extending in different lengths and two belt parts (connections) connecting these interposition parts 13 in the left-right direction along the spherical surface of each ball 11 Part) 14. When the end ball coupling body 4 is curved, the intervening portion 13 has a claw-like interposition portion 13a positioned on the outer side and is positioned on the inner side. The intervening portion 13b is formed short, and even when bent, the nail-like interposing portion 13 and the two belt portions 14 hold the ball 11 so as not to fall off, and the short nail It has a shape that can be easily bent in the direction of the arrow XY with the intervening portion 13b inside.
[0026]
The end ball coupling body 4 is arranged in a mold with each ball 11 as a core, and a molten synthetic resin is injected into the mold to perform insert molding, and then released from the mold, and then molded. The formed end ball coupling body 4 is immersed in a mineral oil-based lubricating oil, and the formed coupling body 12 is swollen to form a gap between each ball 11 and the coupling body 12, thereby each ball 11. Can be freely rotated while being held by the connecting body 12.
[0027]
As shown in FIGS. 6 to 8, the ball circulation tubular body 3 is formed between a pair of tube pieces 15 fitted into a pair of fitting holes 8 formed in the nut member 2 and these tube pieces 15. The unloaded ball passage 10 constituting the endless track of the ball 11 is constituted by a tube body 16 which is connected in communication, and a guide hole 10a formed in a pair of tube pieces 15 and a communication hole 10b formed in the tube body 16. It consists of and.
[0028]
In this embodiment, the pair of tube pieces 15 are formed in the same shape as each other, and each tube piece 15 is made of sintered metal and slanted in the longitudinal direction as shown in FIGS. The guide hole 10a formed in the tube piece 15 has a top surface 15a and a lead hole of the load rolling groove 6 of the nut member 2 from the bottom surface 15b toward the top surface 15a. A guide region extending in the tangential direction along the corner is provided, and a connecting portion 14 of the connecting body 12 of the ball connecting body 4 is slidably fitted into the guide hole 10a. A pair of guide grooves 17 for guiding the four connecting bodies 12 are formed. And this guide groove 17 exists in the position which mutually opposes in any position in the guide hole 10a, From the starting end (the bottom face 15b side of the pipe piece 15) of the load rolling groove 6 side of the nut member 2. The tube body 16 is twisted by a predetermined angle toward the end on the communication hole 10b side (the upper surface 15a side of the tube piece 15), and when the pair of tube pieces 15 are assembled into the nut member 2, In the tube piece 15, the guide grooves 17 that are symmetrical to each other have the same positional relationship at the end of the communication hole 10 b.
[0029]
The fitting hole 8 formed in the nut member 2 is substantially elliptical corresponding to the outer contour shape of each tube piece 15 being substantially elliptical, and The depth is deeper than the length dimension of each pipe piece 15, and the pipe piece 15 is positioned with respect to the nut member 2 by fitting the pipe piece 15 into the fitting hole 8. The upper surface 15a of each tube piece 15 is formed with a positioning step 15c for locking the end of the tube body 16 to position the end of the tube body 16, and the start end side of the tube body 16 and The bent portion 16a formed on the terminal end side is inserted into the fitting hole 8 and the tip thereof is locked to the positioning step portion 15c. The tube body 16 is fixed to the mounting surface 7 of the nut member 2 with the solid metal fitting 9. By doing this A pair of tubes pieces 15 and the tube body 16 is adapted to be secured to the nut member 2.
[0030]
Here, as shown in FIGS. 11 to 16, the tube body 16 is composed of a pair of tube pieces 18 that are formed of synthetic resin and have exactly the same shape. A bent portion 18a that forms the bent portion 16a is formed, and a guide groove 19 that slidably fits the connecting portion 14 of the connecting body 12 of the ball connecting body 4 is formed along the center on the inner surface side. ing.
[0031]
In this embodiment, the cross-sectional shape of the pair of tube pieces 18 is formed as shown in FIG. 13 for the region A → B, and the region C → D is shown in FIG. 14, and the region B → C is formed as shown in FIG. 15. When the tube body 16 is formed by combining a pair of tube pieces 18, the tube body 16 is formed as shown in FIG. 16. A pair of guide grooves 19 are present at positions facing each other on the inner surface side of the communication hole 10a.
[0032]
In this embodiment, the unloaded ball of the tubular body 3 for ball circulation formed by the load rolling groove 6 (load region) of the nut member 2, the guide hole 10 a of the pair of tube pieces 15 and the communication hole 10 b of the tube body 16 is formed. The relationship between the endless track formed by the passage 10 (no-load region) and the end ball coupling body 4 that rolls in the endless track is schematically shown in FIGS. FIG. 17 shows the movement of the end ball coupling body 4 in the endless track and the posture at that time, in particular, the twisted state in the guide hole 10a and the bent state in the bent portion 16a of the tube body 16. FIG. 18 shows the state of the end ball coupling body 4 that rolls in the load rolling groove 6 of the nut member 2, and FIG. 19 shows the state of rolling in the ball rolling groove 5 of the screw shaft 1. The state of the end ball coupling body 4 running is shown That. In addition, in these FIGS. 17-19, the end ball connection body 4 is typically drawn so that the twist of the connection body 12 may be understood easily.
[0033]
The position of the connecting portion 14 of the connecting body 12 of the end ball connecting body 4 that rolls in the endless track is immediately before entering the guide hole 10a of each tube piece 15 or immediately after coming out of the guide hole 10a (load rolling). At the start and end of the groove 6, they are symmetric with each other and are twisted by a predetermined angle in the guide hole 10 a of each tube piece 15, immediately before the tube body 16 side outlet of the guide hole 10 a of each tube piece 15. In the communication hole 10b of the tube body 16 having the same positional relationship with each other and having bent portions 16a at both ends, the same positional relationship is maintained from the start end to the end.
[0034]
Therefore, in this embodiment, the guide holes 10a of the pair of pipe pieces 15 serve as a guide region extending in the tangential direction along the lead angle of the load rolling groove 6 of the nut member 2, and thereby the load on the endless track. The transfer of the ball 11 performed between the region and the no-load region becomes smooth, a predetermined twisting process is performed on the pair of tube pieces 15, and a predetermined bending process is performed on both ends of the tube body 16. As a result, the ball coupling body 4 rolls smoothly in the endless track, and as a result, a smooth circulation movement of the ball is achieved.
[0035]
【The invention's effect】
According to the present invention, in a ball screw device having a ball circulation tubular body, a ball coupling body in which a large number of balls are held in an aligned state and rollable by the coupling body is incorporated in the endless track so that the endless track is free. A guide groove that guides the connected body is formed in the unloaded ball path that forms the load area, and the connected body is moved by each ball in the load rolling groove that forms the load area of the endless track and is connected in the unloaded area. Since each body guides and moves each ball, a guiding part is formed on at least the load rolling groove side of the no-load ball path to guide the connected body along the traveling direction of the ball moving through the loaded rolling groove. The transfer of the ball performed between the load area and the no-load area of the endless track becomes extremely smooth, thereby achieving a smooth circulation movement of the ball.
[0036]
According to the invention of claim 2, in the ball screw device having a ball circulation tubular body, a ball coupling body in which a large number of balls are held in an aligned state and rollable within the endless track. The ball circulation tubular body constituting the no-load region is composed of a pair of tube pieces and a tube body that communicates and connects between the pair of tube pieces, and at least the load rolling groove side of each tube piece A guide hole having a guide region for guiding each ball in the tangential direction along the lead angle of the load rolling groove (or the lead angle of the ball rolling groove) is provided. A connecting portion of the connecting body that constitutes the ball connecting body is slidably fitted in the communicating hole of the tube body that forms a no-load ball passage by connecting and connecting the guide holes to guide the connecting body. Forming guide grooves In the load area of the endless track, the ball is moved by guiding each ball with the link in the no-load area and the ball is moved between the load area and the no-load area of the endless track. The transfer of the ball that is performed is very smooth, whereby a smooth circulating movement of the ball can be achieved.
[0037]
According to the third aspect of the present invention, the guide holes of the pair of tube pieces that communicate and connect between the load rolling groove of the nut member and the unloaded ball passage are disposed from the load rolling groove side start end. Twist and / or bend so that the position of the guide groove at the starting end of the loaded rolling groove side is symmetrical and the position of the guide groove at the end of the unloaded ball path side is the same over the end of the loaded ball path side Therefore, the ball connected body traveling in the endless track of the ball is adjusted in its posture on the direction change path, and thereby the balls constituting the ball connected body are not aligned with each other without interfering with each other. Smoothly circulates in an endless track.
[0038]
Furthermore, according to the invention described in claim 4, the entire length of each guide hole of the pair of pipe pieces is a guiding region, and a part or all of the guide groove of each guide hole is twisted at that position. In addition, a guide groove is formed at the same position from the start end to the end of the tube body that communicates and connects between the pair of tube pieces, and bent portions are formed on the start end side and the end side. Therefore, it is possible to easily impart the necessary twist and bending to the unloaded ball path, thereby forming an unloaded region of an endless track where the ball coupling body can circulate stably, and these tubes The piece and the tube body can be constituted by the minimum necessary parts.
[Brief description of the drawings]
FIG. 1 is a front view showing a tube-type ball screw device according to an embodiment of the present invention.
FIG. 2 is a perspective explanatory view schematically showing a part of an endless track of a ball by cutting out a part of the tube type ball screw device of FIG. 1;
FIG. 3 is an explanatory front view showing a connected end ball assembly incorporated in the tube-type ball screw device of FIG. 1;
FIG. 4 is a partially enlarged view showing an A portion of FIG. 3 in an enlarged manner.
FIG. 5 is a bottom view of FIG. 4;
FIG. 6 is a plan view showing the nut member of FIG. 1;
7 is a cross-sectional explanatory diagram schematically showing two endless tracks in FIG. 1. FIG.
8 is a cross-sectional explanatory view schematically showing an unloaded ball passage formed by the nut member and the ball circulation tubular body of FIG. 1. FIG.
9 is a perspective view showing the tube piece of FIG. 7. FIG.
10 is a front view (a), a plan view (b), and a bottom view (c) showing the tube piece of FIG. 9. FIG.
FIG. 11 is a plan view of one tube piece constituting the tube body of FIG. 8;
FIG. 12 is a front view of the tube piece of FIG.
FIG. 13 is a cross-sectional view of the tube piece of FIG. 12 in the AB region.
FIG. 14 is a cross-sectional view of the tube piece of FIG. 12 in the CD region.
FIG. 15 is a cross-sectional view of the tube piece of FIG. 12 in the B-C region.
FIG. 16 is a cross-sectional view of the tube body of FIG.
FIG. 17 is a partial cross-sectional perspective explanatory view schematically showing an endless track of the ball in the tube type ball screw device of FIG. 1;
18 is a partial cross-sectional perspective explanatory view showing a state of the end ball coupling body that rolls in the load rolling groove of the nut member in the tube type ball screw device of FIG. 1. FIG.
FIG. 19 is a partial cross-sectional perspective explanatory view showing a state of an end ball coupling body that rolls in a ball rolling groove of a screw shaft in the tube type ball screw device of FIG. 1;
FIG. 20 is a plan view showing a conventional ball screw device.
FIG. 21 is a cross-sectional explanatory diagram of FIG. 20;
FIG. 22 is a cross-sectional front view showing another conventional ball screw device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Screw shaft, 2 ... Nut member, 3 ... Tubular body for ball circulation, 4 ... Ended ball coupling body, 5 ... Ball rolling groove, 6 ... Load rolling groove, 7 ... Mounting surface, 8 ... Fitting hole , 9 ... Mounting bracket, 10 ... Unloaded ball passage, 10a ... Guide hole, 10b ... Communication hole, 11 ... Ball, 12 ... Connector, 13a, 13b (13) ... Interposing part, 14 ... Belt part (connecting part) 15 ... piece, 15a ... top surface, 15b ... bottom surface, 15c ... positioning step, 16 ... tube body, 16a ... bending portion, 17 ... guide groove, 18 ... tube piece, 18a ... bending portion, 19 ... guide Groove,

Claims (6)

A screw shaft having a spiral ball rolling groove on the outer peripheral surface, and a nut member having a helical load rolling groove on the inner peripheral surface opposite to the ball rolling groove of the screw shaft and forming a ball load region And a ball circulation tubular body having a no-load ball passage that is attached to the nut member and communicates the start and end of the load region to form an endless track of the ball, and a large number of rolling in the endless track. A tube-type ball screw device including a ball and a ball coupling body formed of a flexible coupling body that holds the balls in an aligned state so as to be rotatable. A guide groove is formed to guide the connection body of the connection body, and the connection body is moved by each ball in the load area, and each ball is guided and moved by the connection body in the unloaded ball path. A pair of guiding areas for guiding each ball in the tangential direction along the lead angle of the load rolling groove is provided on the load area side at both ends of the rail path, and along the traveling direction of the ball in the guiding area. While guiding the connected body ,
While the connecting body is spirally curved along the inner peripheral surface of the nut member in the load region, each connecting region is twisted by a predetermined angle with respect to the connecting body extended in the tangential direction of the load rolling groove. The tube-type ball screw device is characterized in that the connecting body bends in one direction without being twisted in an unloaded ball passage between one guide region and the other guide region . The ball circulation tubular body is composed of a pair of tube pieces having guide holes serving as the guiding regions, and a tube body having a communication hole for communicating and connecting the guide holes of the pair of tube pieces. The tube-type ball screw device according to claim 1, wherein the guide groove is formed continuously over the tube body . The tube-type ball screw device according to claim 2, wherein the pair of tube pieces are formed in the same shape, and the tube body is configured by combining a pair of tube pieces having the same shape. . 3. The tube-type ball screw device according to claim 2, wherein each tube piece has an outer contour shape formed in a non-circular shape and is positioned by being fitted into a non-circular fitting hole formed on the nut member side. . The tube-type ball screw device according to claim 1, wherein one or a plurality of end ball coupling bodies formed of a flexible coupling body having both ends are incorporated in the endless track of the ball. The tube-type ball screw device according to claim 1, wherein one endless ball coupling body having an endless coupling body is incorporated in the endless track of the ball.

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