TWI273183B - Ball screw device for long stroke - Google Patents

Abstract

The present invention related to a ball screw device of long stroke system, comprising a shaft that having a longitudinal cylindrical cavity and is installed two or more material with different ratio of rigidity to density between two ends of hollow section. It is possible to raise the critical speed and suppress vibration in radial direction of this screw shaft during the operation of this system.

Description

1273183 IX. Description of the Invention: [Technical Field] The present invention relates to a device for use in a long-stroke ball screw, particularly for solving the ball screw yaw vibration and improving the overall critical speed effect. [Prior Art] Today's ball screws are used more and more in the industrial field. In addition to the high precision effect of the linear feed drive, other friction loss rate, high energy conversion rate, low noise and high rigidity are also available. It is not easy to damage, so the importance of the ball screw for today's various industrial applications is not to mention. The current ball screw is used for long-stroke linear feed transmission to avoid resonance, and the screw shaft is hollowed out and placed in a material that can improve the overall rigidity. Although the rigidity of the loaded material is large, and the density of the material and the Young's modulus are both uniform, when the rotational motion of the ball screw occurs in a region where the vibration yaw is large, the offset is still large. Therefore, how to place the damping materials of different mechanical properties on the long-stroke ball screw in the length of 1273183 different lengths of the screw to achieve the effect of damping the lx interval of the screw, and the research and development improves the competitiveness. The products naturally become the focus of the current industry. Please refer to the U.S. Patent No. 5,809,829, the first of which is the design of the screw. In order to improve the overall rigidity of the screw, the screw is mainly divided into inner and outer parts. The external part of the screw is made of steel material, and the screw (4) is made of gold-plated material, which has a high modulus of elasticity, which can improve the overall critical speed. However, although this method increases the overall critical speed, when the rolling and the screw rotating motion occur in the vibration yaw, the offset is still large, so there is a need for improvement. In view of the foregoing problems, please refer to the U.S. Patent No. 7, No. 7, 577, which is shown in Fig. 2. The conventional technique disclosed in Fig. 2 is that the screw = design is mainly loaded inside a material magazine. Single fixed = high density surface coarse grained damper element material, its purpose is to improve the vibration frequency and enhance the vibration energy dissipation effect. However, this method can not achieve the effect of improving the boundary speed of the boundary. .

6 1273183 Therefore, the conventional long-stroke ball screw has not been solved at the same time in solving the two problems of the ball screw yaw vibration and the improvement of the overall critical speed. Therefore, the conventional long-stroke ball screw needs to be improved. SUMMARY OF THE INVENTION An object of the present invention is to provide a long-stroke ball screw which can simultaneously solve the two problems of the ball screw yaw vibration and the overall critical speed effect. To achieve the above object, the long-stroke ball screw of the present invention comprises a screw, a nut and a plurality of balls assembled, the screw having a hollow portion and extending shoulders and open ends on both sides, wherein: The screw is provided with a plurality of sections on the inner edge of the hollow portion, and the vibration damping material mixed with different ratios of low density and high rigidity is placed in each section, and the ratio of the outer diameter of the screw to the outer diameter of the vibration damping material of each section may be Equal or unequal, the outer diameter ratio ranges from 0.5 to 0.7. Accordingly, the screw of the present invention induces inertial force in a rotational motion

7 1273183 The resonance frequency generated by the screw's own weight can be placed in the hollow part by the vibration damping material to achieve the effect of damping the various sections of the screw, and the screw can be reduced in the place where the screw weight sag is the largest. The offset in the rotary motion solves the two problems of the ball screw yaw vibration and the overall critical speed effect. For a better understanding of the features and technical aspects of the present invention, reference should be made to the preferred embodiments of the invention, By. [Embodiment] In the embodiment of the present invention, please refer to FIG. 3 to FIG. 1 . The embodiment of the present invention comprises a screw (1), a nut (2) and a plurality of balls (3) assembled. 1) having a hollow portion (4), and extending a shoulder portion (7) and an open end respectively on both sides, wherein: the screw (1) is pre-set in the inner edge of the hollow portion (4) to Low-density, high-rigidity damping materials (5A) and (5B) mixed in different proportions are placed in each section; for further understanding of each component, please refer to Figures 4 to 9, which are partial cross-sectional views of the 1273183 of the present invention, respectively. 'The above is the relationship between the related components of the present invention and its overview. In order to clearly illustrate the implementation features of the present invention, the following is a description of the advantages and practical ways of using this long-stroke ball screw:

When the ball screw of the present invention is assembled, the solid screw is first made into a hollow screw, and the critical speed is reduced according to the combination of different Young's coefficient (E) and density (p) in the axially segmented region. Damping material (5 A), ( 5 B). The stiffness values (e/P) of the damping materials (5A) and (5B) are the highest damping material (5 A) in the region where the maximum weight sag is the largest, and the damping material ($ b) in other regions. Second, the part of the hollow screw is the smallest. Therefore, in the region where the amount of offset vibration is the largest, since the density is the smallest (that is, the amount of f is the smallest under the same volume), and the: coefficient (y_g mQdulus) is the largest, the screw of the segment is In the rotational motion, the inertial force and the screw weight production rate can be set by the damping material (5A) and the vibration frequency (in the case of the screw, the vibration is reduced, and the weight of the screw cup is drooped to the maximum). The place 'can reduce the offset of the screw in the rotation of the 1273183 rotation, solve the ball screw yaw vibration, and the 斟 and 衰 bead screws as a whole will increase the critical speed of the system. Application or use in the development of the invention The theoretical basis is based on the formula of critical speed:

60Λ2 =0.8N c

Among them, five: Young's coefficient, a material density, /: moment of inertia, gravity acceleration, 丄 捍 捍 cross-sectional area, a: boundary condition parameters. In the case where the known geometric shapes are the same, it can be known from the above formula that the rotational speed is proportional to the enthalpy, and if the material of the screw is changed to be higher than the original material, or By inserting the material into the interior of the screw to become a composite material, the critical speed can be increased. Therefore, the present invention not only utilizes such an effect, but also divides the internal material of the hollow screw into different sections in the axial direction to control different vibration effects between the sections. Next, please refer to FIG. The present invention is a partial enlarged cross-sectional view of the present invention, wherein the ratio of the outer diameter of the screw (丨) to the outer diameter of the damping materials (5A) and (5B) of each section may be equal or unequal, and the outer diameter ratio ranges 〇5~〇7. 1273183 Specially for the damping material (5A), (5B) outer diameter ratio range here - and clarify 'the inner diameter of the inner hole due to the inner space of the hollow screw (4) It must be smaller than the outer diameter of the screw shoulder (7), but it should not be too close to the outer diameter (D1) of the screw (1), because if the difference in outer diameter (D i - D 2) is too small, it is processed. It is easy to cause the screw (1) to crack. #内Μ (Vibration material) When the outer diameter D 2 is greater than half of the outer diameter of the screw (1), it depends on the effect of increasing the critical speed. Diameter ratio (damage material outer diameter D 2 / screw outer diameter D work) is the range of 〇5~〇7 Finally, please refer to FIG. 1 for another partial enlarged cross-section of the present invention, wherein the damping materials (5 A) and (5B) of the respective sections are opened close to the screw (1). The outer diameter of the damping material 夤 (5 B ) at the end (〇2) is larger than the outer diameter (D3) of the damping material (5A) away from the open end of the screw (i), ie 〇2/1) 1 is greater than D 3/D 1 . Further, the open end of the hollow portion (4) of the screw (1) is closed by a plug (6) to prevent the vibration-damping materials (5 A) and (5 B) from slipping out. 1273183 Also, the vibration reduction in the number interval The segmented joints of the materials (5A) and (5B) are bonded by silicone, so that different materials can be connected to each other to avoid relative sliding phenomenon. In summary, the screw of the present invention is In the rotational motion, the inertial force and the resonance frequency generated by the self-weight of the screw Φτ can be placed in the hollow portion by the damping material, and the effect of damping the vibration in each section of the screw is repeated, and the maximum weight of the screw is drooped. Place, can reduce the offset of the screw in the rotary motion, and solve the ball screw yaw vibration And to improve the overall critical Weisi two _, and can improve the above-mentioned effects compared with the conventional technology, should be fully in line with the novelty and progressiveness of the statutory invention patent requirements 'Chouton pleading, riding your office to approve this invention patent application Fig. 1 is a front view of a long stroke ball screw. Fig. 2 is a front view of another long stroke ball screw. Fig. 3 is the length of the present invention. 4 is a partial cross-sectional view of Fig. 3, Fig. 5 is a cross-sectional view of Fig. 4, Fig. 4 is a cross-sectional view of Fig. 4, and Fig. 6 is a partial cross-sectional view of Fig. 3 FIG. 8 is a partial cross-sectional view of FIG. 3, FIG. 9 is a c-C cross-sectional view of FIG. 8 and FIG. 1 is a partial enlarged cross-sectional view of the present invention. FIG. Another partial enlarged cross-sectional schematic diagram [main component symbol description] 1 screw 2 nut 3 ball 4 hollow

5 A, 5 B damping material 7 shoulder D 2 damping material outer diameter 6 plug D 1 screw outer diameter D 3 damping material outer diameter

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Claims (1)

1273183 X. Patent scope: 1 · A long-stroke ball screw comprising a screw, a nut and a plurality of balls assembled with a hollow portion and extending shoulders and open ends on both sides, wherein: The screw is pre-set in the inner edge of the hollow portion, and is placed in each section with different damping materials. The outer diameter ratio of the outer diameter of the screw and the outer diameter of the damping material of each section ranges from 0.5 to 0.7. . 2. The long-stroke ball screw according to item 1 of the patent application scope, wherein the damping material of each of the above sections is based on the outer diameter of the damping material of the open end of the screw is larger than the outer diameter of the damping material away from the open end of the screw. . 3. The long-stroke ball screw according to claim 1, wherein the open end of the hollow portion is closed by a plug to prevent the vibration-damping material from slipping out. 4. The long-stroke ball screw according to item 1 of the patent application scope, wherein the segmented joints of the plurality of sections of the vibration-damping material are fast-conducting, so that different materials can be connected to each other to avoid relative sliding phenomenon. . d) 14