Ball screw pair with three-dimensional circulation structure
By designing a ball screw pair with a three-dimensional circulating structure, the vibration and noise problems of the bent tube external circulation ball screw pair during high-speed operation were solved, achieving high-precision and high-speed ball operation and reducing processing difficulty and cost.
Patent Information
- Application Number
- CN202520427980.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-12
- Publication Date
- 2025-12-02
- Estimated Expiration
- 2035-03-12
AI Technical Summary
Existing curved tube-type external circulation ball screw pairs are prone to vibration, increased noise and temperature rise when operating at high speeds, resulting in a decline in overall performance and failing to meet the high precision and high speed requirements of high-end machine tool equipment.
The ball screw pair with a three-dimensional circulation structure achieves smooth ball operation by designing the inner cavity centerline of the bend return device to be tangent to the helical line of the thread raceway and keeping the outer shell centerline on the same plane. Combined with the integrally formed bend return device and a simple guide ball channel mounting groove, it achieves smooth ball operation.
It improves the limiting speed of the ball screw pair, reduces noise and temperature rise, enhances smoothness, meets the application requirements of high-end machine tool equipment, and reduces processing difficulty and cost.
Smart Images
Figure CN223622126U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of ball screw pair technology, and more particularly to ball screw pairs with a three-dimensional circulating structure. Background Technology
[0002] In the field of high-end machine tool equipment, especially in the application scenarios of precision grinding machines and small and medium-sized high-speed machining centers, the key performance indicators of ball screw pairs, such as the limiting speed DN value (ball revolution speed), noise control, and temperature rise management, have a decisive influence on the high precision, high speed, and high dynamic response characteristics of ball screw pairs.
[0003] In the widely used curved tube-type external circulation ball screw assemblies, the circulation structure is a two-dimensional tube design. Both the external outline and the internal cavity follow the principle of two-dimensional planar layout. During the dynamic process of the steel balls entering and exiting the curved tube return mechanism, the circulation path cannot achieve ideal tangential connection. Under high-speed operation, this can easily induce a series of problems such as vibration, increased noise, and temperature rise. These adverse factors directly weaken the overall performance of the ball screw assembly. Utility Model Content
[0004] To solve or improve at least one of the problems mentioned in the background art, this application provides a ball screw pair with a three-dimensional cyclic structure.
[0005] The ball screw pair with a three-dimensional cyclic structure provided in this application includes:
[0006] The nut and lead screw form a threaded raceway between them for the movement of the balls;
[0007] A pipe bend reversing device, wherein the center lines of the outer shell of the pipe bend reversing device are located in the same plane, the pipe bend reversing device includes multiple inner cavities, the center lines of the multiple inner cavities are sequentially tangent to each other, the center lines of the multiple inner cavities are not coplanar, and the center lines of the inner cavities are also tangent to the helix of the thread raceway.
[0008] In at least one embodiment, the pipe bend return device includes a first guide bead channel and a second guide bead channel mounted on the nut and separated in the axial and circumferential directions of the nut.
[0009] The centerline of the inner cavity of the first guide bead channel is tangent to the helix of the thread raceway at one end of the first guide bead channel, and the centerline of the inner cavity of the second guide bead channel is tangent to the helix of the thread raceway at one end of the second guide bead channel. The centerlines of the inner cavities of the first guide bead channel and the second guide bead channel are not coplanar.
[0010] In at least one embodiment, the outer shell of the first guide bead channel and the outer shell of the second guide bead channel are parallel and extend in a straight line.
[0011] In at least one embodiment, the bend return device further includes an arcuate channel, wherein the other end of the center line of the inner cavity of the first guide bead channel is tangent to the center line of the inner cavity of the arcuate channel, and the other end of the center line of the inner cavity of the second guide bead channel is tangent to the center line of the inner cavity of the arcuate channel.
[0012] In at least one embodiment, the arc channel includes a first arc channel and a second arc channel, and the pipe bend return device further includes a straight channel that connects the first arc channel and the second arc channel simultaneously, wherein the center line of the inner cavity of the straight channel is tangent to the center line of the inner cavity of the first arc channel and the center line of the inner cavity of the second arc channel, respectively.
[0013] In at least one embodiment, the pipe bend return device is integrally formed.
[0014] In at least one embodiment, the nut includes a first guide bead channel mounting groove and a second guide bead channel mounting groove that are parallel and extend in a straight line, wherein the first guide bead channel and the second guide bead channel are respectively inserted.
[0015] In at least one embodiment, a first transition surface is provided between the threaded raceway and the first guide ball channel mounting groove on the nut, and a second transition surface is provided between the threaded raceway and the second guide ball channel mounting groove.
[0016] In at least one embodiment, one end of the first guide bead channel and one end of the second guide bead channel have guide bead openings, the side of the guide bead opening facing the nut has a guide bead plate, the side of the guide bead opening facing the lead screw has a guard plate, and the distance between the bottom edge of the guide bead plate and the bottom edge of the guard plate is not greater than the diameter of the ball.
[0017] In at least one embodiment, the ball screw assembly further includes a pressure plate that presses one or more of the bend returners against the nut.
[0018] The inner cavity of the bend return device forms a three-dimensional configuration in which the center line is tangent to the helix, while the outer shell maintains a two-dimensional configuration in which the center line is on the same plane. This allows the balls to run smoothly and reduces the difficulty of processing. Attached Figure Description
[0019] Figure 1 A schematic diagram of a ball screw assembly with a three-dimensional cyclic structure according to an embodiment of this application is shown, which hides part of the nut structure.
[0020] Figure 2 It shows Figure 1 The nut in the middle.
[0021] Figure 3 A schematic diagram of the helix of the bend reversing device and the thread raceway in a ball screw pair with a three-dimensional circulating structure according to an embodiment of this application is shown.
[0022] Figure 4 It shows Figure 3 A front view of the pipe bend return device.
[0023] Figure 5 It shows Figure 4 The top view of the bend return mechanism also shows the inner cavity of the bend return mechanism.
[0024] Explanation of reference numerals in the attached figures
[0025] 100 nuts
[0026] 111 First guide bead channel mounting slot
[0027] 112 Second guide bead channel mounting slot
[0028] 120 arc groove
[0029] 200 lead screw
[0030] 300 threaded raceway
[0031] 310 Second transition surface
[0032] 400 bend reversing device
[0033] 411 First guide bead channel
[0034] 412 Second guide bead channel
[0035] 413 Guide bead opening
[0036] 414 guide plate
[0037] 415 protective plate
[0038] 420 arc channel
[0039] 421 First Arc Channel
[0040] 422 Second Arc Channel
[0041] 430 Straight Channel
[0042] 500 ball bearings
[0043] 600 pressure plate Detailed Implementation
[0044] Exemplary embodiments of this application are described below with reference to the accompanying drawings. It should be understood that these specific descriptions are for teaching those skilled in the art how to implement this application only, and are not intended to exhaustively describe all possible methods of this application, nor to limit the scope of this application.
[0045] This application provides a ball screw pair (hereinafter, sometimes simply referred to as "ball screw pair") with a three-dimensional circulating structure.
[0046] See Figure 1 A ball screw assembly may include a nut 100, a screw 200, a bend return mechanism 400, and balls 500.
[0047] The nut 100 and the lead screw 200 form a threaded raceway 300 for the movement of the ball 500. The ball 500 can be a common steel ball.
[0048] See Figure 3 The bend return mechanism 400 may include a first ball guide channel 411 and a second ball guide channel 412 mounted on the nut 100 and separated axially and circumferentially from the nut 100. Exemplarily, the balls 500 move along the thread raceway 300, entering the bend return mechanism 400 from the first ball guide channel 411, entering the second ball guide channel 412 along the bend return mechanism 400, and then entering the thread raceway 300 at another axial position from the second ball guide channel 412, repeating the aforementioned actions to form a three-dimensional cyclic structure. One or more bend return mechanisms 400 may be installed in the ball screw assembly.
[0049] The centerlines of the housing of the pipe bend reversing device 400 can lie in the same plane. The pipe bend reversing device 400 may also include multiple inner cavities, the centerlines of which are sequentially tangent and not coplanar. The centerlines of the inner cavities are also tangent to the helix (or thread line) of the thread raceway 300.
[0050] For example, the centerline of the inner cavity of the first guide bead channel 411 is tangent to the helix of the thread raceway 300 at one end of the first guide bead channel 411, and the centerline of the inner cavity of the second guide bead channel 412 is tangent to the helix of the thread raceway 300 at one end of the second guide bead channel 412. The centerlines of the inner cavities of the first guide bead channel 411 and the second guide bead channel 412 are not coplanar, and the centerlines of the outer shells of the first guide bead channel 411 and the second guide bead channel 412 are located in the same plane.
[0051] The inventors understand a pipe bending reversing device in which the centerline of the inner cavity and the centerline of the outer shell are collinear. Since the two helices at different axial positions are not coplanar, to maintain the tangency of the inner cavity centerline to the helices, the pipe bending reversing device needs a three-dimensional shape, which is difficult to manufacture. Furthermore, the structure of the corresponding mounting groove in the nut needs to be adapted to the three-dimensional shape of the pipe bending reversing device, which is difficult to manufacture, verify, and costly.
[0052] In one aspect of this application, the design that the center lines of the inner cavities of the first guide ball channel 411 and the second guide ball channel 412 are tangent to the helix of the thread raceway 300 allows for a smoother transition of the ball 500 between the thread raceway 300 and the guide ball channel, enabling the ball 500 to achieve a higher limiting speed. Significant improvements have been achieved in smoothness, noise control, and temperature rise management, meeting the application requirements of high-end CNC machine tool equipment.
[0053] On the other hand, the center line of the outer shell of the first guide bead channel 411 and the center line of the outer shell of the second guide bead channel 412 are located on the same plane, which means that the outer shell of the guide bead channel and the mounting groove of the guide bead channel in the nut 100 can follow the common two-dimensional planar layout principle, making processing more convenient and the bend return device 400 has strong compatibility.
[0054] That is, such as Figures 3 to 5 As shown, the inner cavity of the bend return device 400 forms a three-dimensional configuration in which the center line is tangent to the helix, while the outer shell maintains a two-dimensional configuration in which the center line is on the same plane. This allows the balls to run smoothly and reduces the difficulty of processing.
[0055] In one implementation, see Figure 3 , Figure 4 The outer shell of the first guide bead channel 411 and the outer shell of the second guide bead channel 412 are parallel and extend in a straight line. Their simple design allows for a simpler installation groove for the guide bead channel in the nut 100, reducing processing costs.
[0056] In one implementation, see Figure 3 , Figure 4 The pipe bend return device 400 also includes an arc channel 420, the other end of the center line of the inner cavity of the first guide bead channel 411 is tangent to the center line of the inner cavity of the arc channel 420, and the other end of the center line of the inner cavity of the second guide bead channel 412 is tangent to the center line of the inner cavity of the arc channel 420.
[0057] Furthermore, the arc channel 420 includes a first arc channel 421 and a second arc channel 422, and the pipe bend return device 400 also includes a straight channel 430 connecting the first arc channel 421 and the second arc channel 422. The center line of the inner cavity of the straight channel 430 is tangent to the center line of the inner cavity of the first arc channel 421 and the center line of the inner cavity of the second arc channel 422, respectively.
[0058] In one embodiment, the center lines of the housing of the bend return device 400 are located in the same plane, which facilitates machining. Of course, it is also possible to simply make the center lines of the two guide bead channels located in the same plane.
[0059] In one embodiment, the outer diameter of the bend return device 400 is the same at all positions, which facilitates the uniform size of the mounting groove in the nut 100.
[0060] The inventors also understand a pipe bending reversing device composed of multiple separate structures. For example, the guide post channel, arc channel, and straight channel are set up as multiple independent units, and then these units are combined and connected to form the pipe bending reversing device. This design creates gaps at the connection points of the components. When the ball bearings rotate at high speed in the pipe bending reversing device, this may cause the components to loosen and vibrate, thereby interfering with the smoothness of the ball bearing movement, increasing noise, and affecting overall performance.
[0061] In one embodiment of this application, the pipe bend return device 400 is integrally formed. Integral forming reduces dimensional errors caused by the composition of multiple components, ensuring channel accuracy and overcoming the aforementioned problems. Exemplarily, the pipe bend return device 400 can be manufactured by stainless steel powder metallurgy sintering, giving it high hardness and strong load-bearing capacity.
[0062] In one implementation, see Figure 2 The nut 100 includes a first guide bead channel mounting groove 411 and a second guide bead channel mounting groove 412 that extend parallel to each other along a straight line. The first guide bead channel 411 and the second guide bead channel 412 are respectively inserted into them. The mounting groove has a simple design and is easy to manufacture.
[0063] Furthermore, the nut 100 may also include an arcuate groove 120 that accommodates the arcuate channel 420.
[0064] In one embodiment, a first transition surface is provided between the thread raceway 300 and the first guide ball channel mounting groove 111 on the nut 100, and a second transition surface 310 is provided between the thread raceway 300 and the second guide ball channel mounting groove 112.
[0065] It should be understood that the inner diameter of the ball guide channel is generally larger than the raceway diameter of the thread raceway 300. Therefore, providing a transition surface can make the transition of the ball 500 between the thread raceway 300 and the ball guide channel smoother and reduce jamming. For example, this transition surface can be a curved surface connecting the thread raceway 300 and the ball guide channel mounting groove.
[0066] In one implementation, see Figure 3 , Figure 4 One end of the first guide ball channel 411 and one end of the second guide ball channel 412 have a guide ball opening 413. The side of the guide ball opening 413 facing the nut 100 has a guide ball plate 414, and the side of the guide ball opening 413 facing the lead screw 200 has a guard plate 415. The distance between the bottom edge of the guide ball plate 414 and the bottom edge of the guard plate 415 is not greater than the diameter of the ball 500 to prevent the ball 500 from falling off.
[0067] In one implementation, see Figure 1 The ball screw assembly may also include a pressure plate 600, which presses one or more bend reversing devices 400 against the nut 100. For example, after the bend reversing device 400 is installed in the corresponding mounting slot, the pressure plate 600 can be pressed against the straight channel 430, and then the pressure plate 600 is fixed to the nut 100 by screws. The pressure plate 600 may have a certain degree of elasticity.
[0068] The above description is the preferred embodiment of this application. It should be noted that, for those skilled in the art, several improvements and modifications can be made without departing from the principle of this application, and these improvements and modifications should also be considered within the scope of protection of this application.
Claims
1. A ball screw assembly with a three-dimensional circulating structure, characterized in that, include: The nut and lead screw form a threaded raceway between them for the movement of the balls; A pipe bend reversing device, wherein the center lines of the outer shell of the pipe bend reversing device are located in the same plane, the pipe bend reversing device includes multiple inner cavities, the center lines of the multiple inner cavities are sequentially tangent to each other, the center lines of the multiple inner cavities are not coplanar, and the center lines of the inner cavities are also tangent to the helix of the thread raceway.
2. The ball screw assembly with a three-dimensional circulating structure according to claim 1, characterized in that, The pipe bending return device includes a first guide bead channel and a second guide bead channel that are installed on the nut and separated in the axial and circumferential directions of the nut. The centerline of the inner cavity of the first guide bead channel is tangent to the helix of the thread raceway at one end of the first guide bead channel, and the centerline of the inner cavity of the second guide bead channel is tangent to the helix of the thread raceway at one end of the second guide bead channel. The centerlines of the inner cavities of the first guide bead channel and the second guide bead channel are not coplanar.
3. The ball screw assembly with a three-dimensional circulating structure according to claim 2, characterized in that, The outer shell of the first guide bead channel and the outer shell of the second guide bead channel are parallel and extend in a straight line.
4. The ball screw assembly with a three-dimensional circulating structure according to claim 3, characterized in that, The bend return device also includes an arc channel, the other end of the center line of the inner cavity of the first guide bead channel is tangent to the center line of the inner cavity of the arc channel, and the other end of the center line of the inner cavity of the second guide bead channel is tangent to the center line of the inner cavity of the arc channel.
5. The ball screw assembly with a three-dimensional circulating structure according to claim 4, characterized in that, The arc channel includes a first arc channel and a second arc channel. The pipe bending return device also includes a straight channel that connects the first arc channel and the second arc channel. The center line of the inner cavity of the straight channel is tangent to the center line of the inner cavity of the first arc channel and the center line of the inner cavity of the second arc channel, respectively.
6. The ball screw assembly with a three-dimensional circulating structure according to claim 1, characterized in that, The pipe bend return device is integrally formed.
7. The ball screw assembly with a three-dimensional circulating structure according to claim 3, characterized in that, The nut includes a first guide bead channel mounting groove and a second guide bead channel mounting groove that are parallel and extend along a straight line, and the first guide bead channel and the second guide bead channel are respectively installed therein.
8. The ball screw assembly with a three-dimensional circulating structure according to claim 7, characterized in that, On the nut, a first transition surface is provided between the threaded raceway and the first guide ball channel mounting groove, and a second transition surface is provided between the threaded raceway and the second guide ball channel mounting groove.
9. The ball screw assembly with a three-dimensional circulating structure according to claim 2, characterized in that, One end of the first guide ball channel and one end of the second guide ball channel have guide ball openings. The side of the guide ball opening facing the nut has a guide ball plate, and the side of the guide ball opening facing the lead screw has a guard plate. The distance between the bottom edge of the guide ball plate and the bottom edge of the guard plate is not greater than the diameter of the ball.
10. The ball screw pair with a three-dimensional circulating structure according to claim 1, characterized in that, The ball screw assembly also includes a pressure plate that presses one or more of the bend returners against the nut.