Ball screw pair external circulation combined cannula type reverser assembly

Abstract

The present application belongs to the technical field of ball screw, and relates to a ball screw pair outer circulation combined insertion pipe type reverser assembly, which comprises a screw nut, an inner hole of the screw nut is threadedly connected with a screw, the screw nut is provided with a ball returning track, the ball returning track comprises at least one lower half track which is spirally arranged on a circumferential surface of the screw nut, two ends of the lower half track are respectively and smoothly communicated with insertion pipe holes arranged on the screw nut, a reverser is consistent with the number of the lower half track and is correspondingly matched with the lower half track, an upper half track formed by an inner wall of the reverser is matched with the corresponding lower half track and forms a closed ball movement route with a spiral track on a surface of the screw, and a sleeve is sleeved on the screw nut to form radial location of the reverser. The present application can reduce assembly difficulty of the reverser, reduce impact and jam risk of ball reversing, avoid stress concentration of unilateral track, improve overall carrying capacity and fatigue life, and reduce maintenance cost.

Description

Technical Field

[0001] This invention belongs to the field of ball screw technology and relates to a ball screw pair external circulation combined insert-type reverser assembly. Background Technology

[0002] A ball screw assembly is a common transmission device used for converting between rotary and linear motion, or for positioning. It consists of a screw and nut with built-in helical raceways, multiple balls, and a reversing mechanism. Efficient transmission and positioning are achieved through the rolling of the balls between the helical raceways of the screw and nut. Ball screw assemblies are characterized by high precision, high load capacity, low friction, and high efficiency, and are therefore widely used in mechanical equipment, such as CNC machine tools, automated production lines, aerospace equipment, and the automotive industry.

[0003] The reversing device in a ball screw assembly is used to enable the balls to circulate in the helical raceway. Its performance directly affects the transmission quality. Currently, reversing devices suffer from problems such as high noise, poor durability, and difficult installation and maintenance. Therefore, there is a need to design a reversing device that is easy to assemble and provides smooth operation. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a ball screw pair external circulation combined insert-type reverser assembly, which can reduce the assembly difficulty of the reverser, reduce the impact and jamming risk during ball reversal, avoid stress concentration on one side of the raceway, improve the overall load-bearing capacity and fatigue life, and reduce maintenance costs.

[0005] According to the technical solution of the present invention: a ball screw pair external circulation combined insert-type reversing device assembly includes a screw nut, the inner hole of the screw nut is threadedly connected to the screw, and the screw nut is provided with a ball return raceway, characterized in that the ball return raceway includes:

[0006] At least one lower raceway is spirally arranged on the circumferential surface of the lead screw nut, and the two ends of the lower raceway are smoothly connected to the insertion hole provided on the lead screw nut.

[0007] The number of the reverser is the same as that of the lower half raceway and it is matched with the corresponding lower half raceway. The upper half raceway constructed on the inner wall of the reverser is matched with the corresponding lower half raceway and forms a closed ball movement path with the helical raceway on the surface of the lead screw.

[0008] A sleeve is fitted onto the lead screw nut to provide radial limiting for the reversing device.

[0009] As a further improvement of the present invention, the two ends of the reverser are respectively provided with integrally connected cylindrical insert tubes. After the reverser is correspondingly engaged with the lower half raceway, the end face of the insert tube is supported on the positioning step provided on the inner wall of the insert tube hole.

[0010] The positioning step has a radially extending notch to form a positioning groove, and the outer end face of the insertion tube is constructed with an integrally connected ball guide structure, which is fitted into the positioning groove.

[0011] As a further improvement of the present invention, the working surface of the ball guide structure is arc-shaped.

[0012] As a further improvement of the present invention, an integrally connected anti-torsion structure is constructed on both sides of the reverser in the width direction. The anti-torsion structure is fitted onto the limiting parts respectively provided on both sides of the lower half raceway to prevent the reverser from tortuous deformation.

[0013] As a further improvement of the present invention, the curve of the upper half raceway is divided into three segments, wherein the middle segment is an elliptical arc, and the two ends are modified polynomial transition segments, and the curves at the two ends are symmetrical about the middle segment.

[0014] The transition segments at both ends use a 5th-degree polynomial (t∈[-1,-k]U[k,1]):

[0015]

[0016] Where R is the radius of rotation and is related to the lead screw pitch P: (η≈1.1~1.3 is the margin coefficient), H is the maximum height of the return bead groove, k controls the proportion of the elliptical segment range, and L is the length of the elliptical segment. e =2kR, γ is the lateral polynomial term to adjust the lateral impact of the balls at the inlet / outlet, and β is the longitudinal fifth term to adjust the normal acceleration of the balls when they cut into the thread.

[0017] The intermediate elliptical arc segment (t∈[-k, k]):

[0018]

[0019] Where λ∈(0,0.15) is the elliptic correction coefficient, controlling the curvature transition, implicitly representing the elliptic equation:

[0020] The technical advantages of this invention are as follows: 1) The upper and lower raceways are joined to form a continuous ball return path, reducing the impact and jamming risk during ball reversal. The ball guide structure assists the balls in smoothly entering the insertion tube, avoiding deviation of the movement trajectory. 2) The split design allows for individual disassembly or replacement of the upper raceway, reducing maintenance costs. 3) The upper and lower raceways share the ball pressure, avoiding stress concentration on one side of the raceway, and improving the overall load-bearing capacity and fatigue life. 4) The ball return curve, through a segmented design, integrates the advantages of polynomial and sine functions, achieving a balance between dynamic performance and manufacturing feasibility. Attached Figure Description

[0021] Figure 1 This is an exploded view of the present invention.

[0022] Figure 2 This is a front view of the inverter of the present invention.

[0023] Figure 3 This is a perspective view of the inverter of the present invention.

[0024] Figure 4 This is a front view of the lead screw nut of the present invention.

[0025] Figure 5 for Figure 4 A sectional view along line AA.

[0026] Figure 6 This is a perspective view of the lead screw nut of the present invention.

[0027] The reference numerals in the attached drawings are as follows: 1. Nut; 2. Reversing device; 3. Lead screw; 4. Sleeve; 5. Upper raceway; 6. Anti-torsion structure; 7. Insertion tube; 8. Ball guide structure; 9. Lower raceway; 10. Limiting part; 11. Insertion tube hole; 12. Positioning groove; 13. Positioning step. Detailed Implementation

[0028] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings.

[0029] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. The described embodiments are merely some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0030] like Figures 1-6 As shown, the present invention is a ball screw pair external circulation combined insert-type reversing device assembly, including a ball screw nut 1, the inner hole of the ball screw nut 1 is threadedly connected to a ball screw 3, the ball screw nut 1 is provided with a ball return raceway, the ball return raceway includes at least one lower half raceway 9, which is spirally arranged on the circumferential surface of the ball screw nut 1, and the two ends of the lower half raceway 9 are smoothly connected to the insert hole 11 provided on the ball screw nut 1.

[0031] Each lower half of the raceway 9 is equipped with a reverser 2. The upper half of the raceway 5 constructed on the inner wall of the reverser 2 cooperates with the corresponding lower half of the raceway 9 to form a return ball raceway. The upper half of the raceway 5, the lower half of the raceway 9 and the spiral raceway on the surface of the lead screw 3 form a closed ball movement path.

[0032] In order to achieve radial limiting of the reverser 2, a sleeve 4 is fitted on the lead screw nut 1. It can be understood that in order to ensure a reliable fastening connection between the sleeve 4 and the lead screw nut 1, the sleeve 4 and the lead screw nut 1 adopt an interference fit, and the sleeve 4 covers all the reversers 2.

[0033] Furthermore, the two ends of the inverter 2 are respectively provided with integrally connected cylindrical insertion tubes 7. After the inverter 2 and the lower half of the raceway 9 are correspondingly engaged, the end face of the insertion tube 7 is supported on the positioning step 13 provided on the inner wall of the insertion tube hole 11, so as to achieve reliable positioning of the inverter 2.

[0034] Furthermore, an integrally connected anti-torsion structure 6 is constructed on both sides of the reverser 2 in the width direction. The anti-torsion structure 6 is fitted onto the limiting parts 10 respectively provided on both sides of the lower half raceway 9 to prevent the reverser 2 from tortuous deformation. The anti-torsion structure 6 is a positioning piece integrally connected to the reverser 2.

[0035] To guide the balls back into the raceway of the lead screw 3 during operation, a radially extending notch is provided in the positioning step 13 to form a positioning groove 12. An integrally connected ball guide structure 8 is constructed on the outer end face of the insertion tube 7, and the ball guide structure 8 is fitted into the positioning groove 12. It is understood that the working surface of the ball guide structure 8 is arc-shaped.

[0036] The curve of the upper half of the raceway 5 is divided into three segments, with the middle segment being an elliptical arc and the two ends being modified polynomial transition segments. The curves at the two ends are symmetrical about the middle segment.

[0037] The transition segments at both ends use a 5th-degree polynomial (t∈[-1,-k]U[k,1]):

[0038]

[0039] Where R is the radius of rotation and is related to the lead screw pitch P: Here, H is the margin coefficient, H is the maximum height of the bead return groove, k controls the proportion of the elliptical segment range, and L is the length of the elliptical segment. e =2kR, γ is the lateral polynomial term to adjust the lateral impact of the balls at the inlet / outlet, and β is the longitudinal fifth term to adjust the normal acceleration of the balls when they cut into the thread.

[0040] The intermediate elliptical arc segment (t∈[-k, k]):

[0041]

[0042] Where λ∈(0, 0.15) is the elliptic correction coefficient, controlling the curvature transition, implicitly representing the elliptic equation:

[0043] like Figures 1-6As shown, during assembly, the insert 7 of the reverser 2 is installed from the outside to the inside of the insert hole 11 of the lead screw nut 1. At this time, the anti-torsion structure 6 of the reverser 2 is constrained by the limiting part 10 of the lead screw nut 1 to prevent the reverser 2 from tortuous deformation. The lower half raceway 9 of the lead screw nut 1 and the upper half raceway 5 of the reverser 2 together form the return ball raceway of the external circulation combined insert type reverser. Then, the sleeve 4 is tightened on the lead screw nut 1 to cover all the reversers 2 on the surface of the lead screw nut 1 to prevent the reversers 2 from falling off during the operation of the ball screw pair.

[0044] Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A ball screw pair external circulation combined insert-type reversing device assembly, comprising a screw nut (1), the inner hole of the screw nut (1) being threadedly connected to a screw (3), the screw nut (1) being provided with a ball return raceway, characterized in that, The ball return raceway includes: At least one lower raceway (9) is spirally arranged on the circumferential surface of the lead screw nut (1), and the two ends of the lower raceway (9) are smoothly connected to the insertion hole (11) provided on the lead screw nut (1); The number of the reverser (2) is the same as that of the lower half raceway (9) and it is matched with the corresponding lower half raceway (9). The upper half raceway (5) constructed on the inner wall of the reverser (2) is matched with the corresponding lower half raceway (9) and forms a closed ball movement path with the spiral raceway on the surface of the lead screw (3). Sleeve (4) is fitted onto the lead screw nut (1) to form a radial limit on the reverser (2); The upper half of the raceway (5) is divided into three segments, with the middle segment being an elliptical arc and the two ends being modified polynomial transition segments. The curves at both ends are symmetrical about the middle segment. The transition sections at both ends use a fifth-degree polynomial: ; Where R is the radius of rotation and is related to the lead screw pitch P: η≈1.1~1.3 is the margin coefficient, H is the maximum height of the return bead groove, k controls the proportion of the elliptical segment range, and L is the length of the elliptical segment. e =2kR, γ is the lateral polynomial term to adjust the lateral impact of the balls at the inlet / outlet, and β is the longitudinal fifth term to adjust the normal acceleration of the balls when they cut into the thread. The middle elliptical arc segment: Where λ∈(0,0.15) is the elliptic correction coefficient, controlling the curvature transition, implicitly representing the elliptic equation: .

2. The ball screw pair external circulation combined insert-type reverser assembly as described in claim 1, characterized in that: The two ends of the reverser (2) are respectively provided with integrally connected cylindrical inserts (7). After the reverser (2) and the lower half of the raceway (9) are correspondingly matched, the end face of the insert (7) is supported on the positioning step (13) provided on the inner wall of the insert hole (11). The positioning step (13) is provided with a radially extending notch to form a positioning groove (12). The outer end face of the insertion tube (7) is constructed with an integrally connected ball guide structure (8), which is fitted into the positioning groove (12).

3. The ball screw pair external circulation combined insert-type reverser assembly as described in claim 2, characterized in that: The working surface of the ball guide structure (8) is arc-shaped.

4. The ball screw pair external circulation combined insert-type reverser assembly as described in claim 1, characterized in that: The anti-torsion structure (6) is integrally connected on both sides of the width direction of the reverser (2). The anti-torsion structure (6) is provided on the limiting part (10) provided on both sides of the lower half raceway (9) to prevent the reverser (2) from tortuous deformation.

Images