Internal Circulation Ball Screw

Abstract

To provide an internal circulation type ball screw which improves convenience during installation and at the same time solves the problem of a positioning unit coming off a positioning groove. [Solution] The internal circulation type ball screw 10 comprises a screw shaft 20, a nut 30, a positioning unit 40 and a reflux unit 50. The nut is movably mounted on the screw shaft, and the load path is between the nut and the screw shaft. The nut has a mounting groove 34 and a positioning groove 36 relatively connected to the two mounting grooves. The positioning unit is detachably disposed in the positioning groove of the nut. The reflux unit is positioned in the mounting groove of the nut by the positioning unit, and the non-load path is between the nut and the positioning unit. The non-load path is connected to the load path. The reflux unit has a position limiting portion 56 on the outside. The position limiting portion of the reflux unit is located between the two opposing ends of the positioning unit, and thus prevents the reflux unit from coming off the positioning groove when the positioning unit rotates.

Description

[Technical field]

[0001] This invention relates to an internal recirculating ball screw, and more particularly to an internal recirculating ball screw that is easy to install. [Background technology]

[0002] The ball screw disclosed in Patent Document 1 has a C-ring on the top surface of the reflux unit. The reflux unit is stabilized within the nut's mounting hole by a C-ring to prevent it from falling off. However, the nut acts and rotates the C-ring relative to the reflux unit. When the C-ring rotates, it may fall off the concave grooves on both sides and lose its positioning effect on the reflux unit, increasing the risk of the reflux unit falling off the mounting hole of the nut. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 7487635 B2 publication Summary of the Invention [Problem to be solved by the invention]

[0004] The main objective of this invention is to provide an internal recirculation type ball screw that is easy to install and prevents parts from falling off. [Means for solving the problem]

[0005] In order to solve the above-mentioned problems, the internal circulation ball screw includes a screw shaft, a nut, a positioning unit, a reflux unit, and a plurality of balls. The screw shaft has an outer screw groove. The nut has a shaft hole, an inner screw groove, a mounting groove, and two opposing positioning grooves. The nut is movably mounted on the screw shaft through the shaft hole. The inner screw groove is formed on the wall surface of the shaft hole, and the load path is formed between the inner screw groove and the outer screw groove of the screw shaft. The mounting groove is formed on the outside of the nut and is connected to the shaft hole in the radial direction. The two positioning grooves are formed on the wall surface of the mounting groove and are connected to the mounting groove. The positioning unit is detachably disposed in the positioning groove of the nut. The reflux unit is stabilized in the mounting groove of the nut by the positioning unit, and has a position limiting portion on the outside. The position limiting portion of the reflux unit is located between the two opposing ends of the positioning unit. The reflux unit has a reflux groove on the inside. The reflux groove of the reflux unit and the outer screw groove of the screw shaft form a non-load path. The non-load path and the load path are connected to each other to form a circulation path for rolling the plurality of balls.

[0006] In detail, when installing the reflux unit, the reflux unit is installed from above into the installation groove of the nut below, and then the positioning unit is installed into the positioning groove of the nut to complete the installation of the reflux unit. After the installation of the reflux unit is completed, the positioning unit is restricted within the installation groove by the position limiting part of the reflux unit and rotates, which effectively prevents the positioning unit from falling off, i.e., the purpose of the present invention is achieved.

[0007] In a relatively preferred case, the positioning unit has an arc portion. The reflux unit has a release groove on the outside. The arc portion of the positioning unit and the release groove of the reflux unit overlap each other. When removing the positioning unit from the positioning groove, the positioning unit can be removed from the positioning groove by inserting a release tool into the release groove and applying force, which is convenient for installation and removal.

[0008] In a more preferred embodiment, the nut has two opposing inner convex edges, which are formed by protruding from the wall of the mounting groove and are closer to the axial hole than the positioning groove, and the reflux unit has outer convex edges at both ends, respectively, which are abutted against the two inner convex edges of the nut to stabilize the reflux unit in the mounting groove.

[0009] In a more preferred case, the positioning unit is a C-shaped ring with a positioning part. Each positioning groove has a straight part and an inclined part, the extension direction of the straight part is parallel to the axial direction of the screw shaft, and the inclined part is connected to one end of the straight part. Due to the above-mentioned structural features, the positioning part of the positioning unit slides into the positioning groove along the inclined part of the positioning groove and retreats from the positioning groove, which improves the convenience of installation and removal.

[0010] (Formula 1) TIFF0003250164000002.tif13145

[0011] In a relatively preferred case, the positioning unit is a C-ring. The maximum outer diameter of the positioning unit fitted into the positioning groove is defined as D1. The maximum outer diameter of the positioning unit released from the positioning groove and pressed down by the wall of the mounting groove is defined as D2. The width of the mounting groove is defined as W. The relationship between the three satisfies Equation 1. The above relationship can improve the convenience of attaching and detaching the positioning unit.

[0012] In a more preferred embodiment, the positioning unit has a slot between the two ends, and the position limiting portion of the reflux unit is located within the slot of the positioning unit.

[0013] The detailed structure, features, assembly and usage of the internal recirculation ball screw according to the present invention will be made clear through the detailed description of the following embodiment. It should be understood by those skilled in the art that the following detailed description and the embodiment presented by the present invention are merely examples for explaining the present invention and cannot limit the scope of the claims of the present invention. [Brief description of the drawings]

[0014] [Figure 1] 1 is a perspective view of an internal circulation type ball screw according to an embodiment of the present invention; FIG. [Diagram 2] 1 is an exploded perspective view of an internal circulation type ball screw according to an embodiment of the present invention; FIG. [Diagram 3] 1 is a cross-sectional view of an internal circulation type ball screw according to an embodiment of the present invention; [Figure 4] 4 is a top plan view of an internal circulation type ball screw according to an embodiment of the present invention, showing a state in which a positioning unit is fitted into a positioning groove of a nut; FIG. [Diagram 5] FIG. 5 is an enlarged view showing a portion of FIG. [Figure 6] 4 is a top plan view of an internal circulation type ball screw according to an embodiment of the present invention, showing a state in which a positioning unit is detached from a positioning groove of a nut; FIG. [Figure 7] 1 is a top view of a different type of position limiting portion of an internal circulation type ball screw according to an embodiment of the present invention; FIG. [Figure 8] 1 is a top view of a different type of position limiting portion of an internal circulation type ball screw according to an embodiment of the present invention; FIG. [Figure 9] 1 is a top view of a release groove at different positions of an internal circulation type ball screw according to an embodiment of the present invention; FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] The internal recirculating ball screw of the present invention will be described below with reference to the drawings. In the specification and drawings, directional terms are expressed according to the directions in the drawings. The same reference numerals indicate the structural features of the same or similar parts.

[0016] (One embodiment) As shown in FIGS. 1 and 2, an internal circulation type ball screw 10 according to an embodiment of the present invention includes a screw shaft 20, a nut 30, a positioning unit 40, a circulation unit 50 and a number of balls 60.

[0017] The screw shaft 20 has an outer screw groove 22 that extends along the outer periphery and axial direction.

[0018] The nut 30 has an axial hole 31 extending through two opposing end faces, an internal thread groove 32, a mounting groove 34, two positioning grooves 36 and two internal convex edges 38. The nut 30 is attached to the screw shaft 20 so as to be movable along the axial direction A of the screw shaft 20 via a shaft hole 31 . The inner screw groove 32 is formed on the wall surface of the shaft hole 31, and a load path 62 (see FIG. 3) is formed between the inner screw groove 32 and the outer screw groove 22 of the screw shaft 20. The mounting groove 34 is formed on the outer side of the nut 30 and is radially connected to the shaft hole 31 . The two positioning grooves 36 are formed relative to the wall surface 342 of the mounting groove 34 and are connected to the mounting groove 34 . As shown in FIG. 3, each positioning groove 36 has a straight portion 362 and two inclined portions 364 . The extending direction of the straight portion 362 is parallel to the axial direction A of the screw shaft 20 . Two inclined sections 364 are connected to both ends of the straight section 362 . The two inner convex edge portions 38 are formed so as to protrude from the wall surfaces at both ends of the mounting groove 34, and are closer to the shaft hole 31 than the positioning groove 36, as shown in FIG.

[0019] The positioning unit 40 has two opposing positioning portions 42 , two opposing ends 44 and an arcuate portion 46 . Each of the two opposing positioning portions 42 has one end connected to the end portion 44 to form a notch 48 between the two end portions 44, and the other end connected to the arc portion 46. In this embodiment, the positioning unit 40 is a C-ring. As shown in Figures 4 and 5, the two positioning portions 42 of the positioning unit 40 each slide into or retract from the positioning groove 36 along one of the inclined portions 364, thereby improving the convenience of installation and removal. The two positioning portions 42 of the positioning unit 40 slide into the positioning grooves 36 and then abut against the straight portions 362 .

[0020] The reflux unit 50 has separate outer convex edges 52 on either end. When the reflux unit 50 is mounted in the mounting groove 34 of the nut 30, the two outer convex edges 52 abut against the two inner convex edges 38 of the nut 30 to support the reflux unit 50, so that the reflux unit 50 is stabilized in the mounting groove 34 while being restricted by the positioning unit 40. As shown in FIG. 3, the reflux unit 50 has four reflux grooves 54 on the inside. The return groove 54 of the return unit 50 and the outer screw groove 22 of the screw shaft 20 form a non-load path 64 . The non-loaded path 64 and the loaded path 62 are interconnected to form a circulating path 66 that allows the plurality of balls 60 to roll.

[0021] As shown in FIGS. 4 and 5, the reflux unit 50 has a position limiting portion 56 on the outside. The position limiting portion 56 of the reflux unit 50 is disposed within the notch 48 of the positioning unit 40 to restrict rotation of the positioning unit 40 . The position limiting portion 56 may have different shapes according to actual needs. In this embodiment, the position limiting portion 56 is triangular, but is not limited thereto, and may also be rectangular (see FIG. 7) or circular (see FIG. 8). In other words, the shape does not matter as long as it can be inserted into the notch 48 of the positioning unit 40 to restrict rotation of the positioning unit 40 . 4, the circulation unit 50 has a release groove 58 on the outside. The release groove 58 of the circulation unit 50 and the arc portion 46 of the positioning unit 40 overlap each other. In this embodiment, the mounting groove 58 is located in the center of the outside of the reflux unit 50 as shown in FIG. 4, but is not limited to this and may be located on the outer edge of the reflux unit 50 as shown in FIG. 9 in order to withstand the impact of the ball 60. The structural features described above ensure that the structural strength of the reflux unit 50 is sufficiently maintained.

[0022] When performing the assembly work, the reflux unit 50 is attached from above into the mounting groove 34 of the nut 30 below, and then the two positioning portions 42 of the positioning unit 40 are inserted into the two positioning grooves 36 of the nut 30 along the two inclined portions 364 of the two positioning grooves 36, thereby completing the installation work of the reflux unit 50. After the installation work of the reflux unit 50 is completed, the positioning unit 40 rotates while being restricted within the installation groove 34 by the position limiting portion 56 of the reflux unit 50, thereby effectively preventing the positioning unit 40 from falling off and stabilizing the reflux unit 50 within the installation groove 34 of the nut 30.

[0023] (Formula 1) TIFF0003250164000003.tif13145

[0024] When removing the positioning unit 40, a release tool (not shown in the figure) is fitted into the release groove 58, and then the release tool is used to press the arc portion 46 of the positioning unit 40 to forcibly detach the two positioning portions 42 of the positioning unit 40 from the two positioning grooves 36 along the two inclined portions 364, thereby allowing the positioning unit 40 to be removed. When the two positioning portions 42 of the positioning unit 40 are fitted into the two positioning grooves 36, the maximum outer diameter of the positioning unit 40 is defined as D1 (see FIG. 4). When the two positioning portions 42 of the positioning unit 40 are detached from the positioning groove 36 and pressed together by the wall surfaces 342 of the mounting groove 34, the maximum outer diameter of the positioning unit 40 is defined as D2 (see FIG. 6). The width of the mounting groove 34 is defined as W. The relationship between the three satisfies Equation 1. Due to the above-mentioned relationship, it is possible to improve the convenience when attaching and detaching the positioning unit 40. [Explanation of symbols]

[0025] 10: Internal circulation ball screw 20: Screw shaft 22: Outer screw groove 30: Nut 31: Shaft hole 32: Internal thread groove 34: Mounting groove 342: Wall 36: Positioning groove 362: Straight line part 364: Inclined part 38: Medial convex margin 40: Positioning unit 42: Positioning section 44: End 46: Arc section 48: Missing edge 50: Reflux unit 52: Outer convex margin 54: Reflux groove 56: Position restriction section 58: Release groove 60: Ball 62: Load path 64: Non-load path 66:Circulation route A: Axial direction

Claims

1. The screw shaft includes a nut, a positioning unit, a reflux unit, and a plurality of balls. The screw shaft has an outer screw groove, The nut has an axial hole, an internal thread groove, a mounting groove and two opposing locating grooves; The nut is movably fitted over the screw shaft through the shaft hole, the inner screw groove is formed on the wall surface of the shaft hole, and a load path is formed between the inner screw groove and the outer screw groove of the screw shaft, the mounting groove is formed on the outside of the nut and is connected to the shaft hole in the radial direction, and the two positioning grooves are formed on the wall surface of the mounting groove and are connected to the mounting groove, The positioning unit is located in the mounting groove of the nut and is removably mounted in the positioning groove of the nut; The positioning unit has two opposing ends; The circulation unit is stabilized in the mounting groove of the nut by the positioning unit, and has a position limiting portion on the outside, the position limiting portion being located between the two opposite ends of the positioning unit; The circulation unit further has a circulation groove on the inside, the circulation groove of the circulation unit and the outer screw groove of the screw shaft form a non-loaded path, and the non-loaded path and the loaded path are interconnected to form a circulation path, An internal circulation type ball screw, characterized in that a plurality of the balls are loaded into the circulation path.

2. The positioning unit has an arcuate portion, The circulation unit further has a release groove on the outside, 2. The internal circulation type ball screw according to claim 1, wherein the arc portion of the positioning unit and the release groove of the circulation unit overlap each other.

3. The nut has two opposing inner convex edges, each of which is formed to protrude from the wall surface of the mounting groove and is closer to the shaft hole than the positioning groove; The internal circulation type ball screw according to claim 1, characterized in that the circulation unit has outer convex edges at both ends, and the two outer convex edges of the circulation unit abut the two inner convex edges of the nut.

4. The positioning unit is a C-ring; Each of the positioning grooves of the nuts has a straight portion and an inclined portion, the extension direction of the straight portion is parallel to the axial direction of the screw shaft, and the inclined portion is connected to one end of the straight portion, The positioning unit further includes two opposing positioning portions, each of which slides into or retracts from the positioning groove along the inclined portion; 2. The internal circulation type ball screw according to claim 1, wherein each of the positioning portions slides into a positioning groove and abuts against the linear portion.

5. The positioning unit has a notch between the two ends, 2. The internal circulation type ball screw according to claim 1, wherein the position limiting portion of the circulation unit is located within the notch of the positioning unit.

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