Ball screw pair with three-dimensional circulation structure

Abstract

The invention provides a ball screw pair with a three-dimensional circulation structure. The ball screw pair comprises a nut, a lead screw and a bent pipe reverser. A threaded raceway for the balls to move is formed between the nut and the lead screw. The elbow reverser comprises a first bead guide channel and a second bead guide channel which are installed on the nut and separated in the axial direction and the circumferential direction of the nut, and the center line of an inner cavity of the first bead guide channel is tangent to the spiral line of the threaded roller path at one end of the first bead guide channel. The center line of an inner cavity of the second bead guide channel is tangent to the spiral line of the threaded roller path at one end of the second bead guide channel, the center line of an inner cavity of the first bead guide channel and the center line of an inner cavity of the second bead guide channel are not coplanar, and the center line of a shell of the first bead guide channel and the center line of a shell of the second bead guide channel are located on the same plane.

Description

Technical Field

[0001] The present application relates to the technical field of ball screw pairs, and in particular to a ball screw pair with a three-dimensional circulation structure. Background Art

[0002] In the field of high-end machine tool equipment, especially in the application scenarios of precision grinders and small and medium-sized high-speed machining centers, key performance indicators such as the ball screw pair's maximum speed DN value (steel ball revolution speed), noise control, and temperature rise management have a decisive influence on the ball screw pair's ability to achieve high precision, high speed, and high dynamic response characteristics.

[0003] In the currently widely used curved tube external circulation ball screw pair, the circulation structure is a two-dimensional plug-in design. Both the appearance contour and the internal cavity follow the two-dimensional layout principle. In the dynamic process of the steel ball entering and exiting the curved tube return device, the circulation path cannot achieve ideal tangential connection, and a series of problems such as vibration, increased noise and increased temperature are easily induced under high-speed operation. These unfavorable factors directly weaken the overall performance of the ball screw pair. Summary of the invention

[0004] In order to solve or improve at least one of the problems mentioned in the background technology, the present application provides a ball screw pair with a three-dimensional circulation structure.

[0005] The ball screw pair with a three-dimensional circulation structure provided in the present application includes:

[0006] The nut and the lead screw form a thread raceway for the ball to move;

[0007] A pipe bending return device includes a first bead guide channel and a second bead guide channel which are installed on the nut and separated in the axial and circumferential directions of the nut, the center line of the inner cavity of the first bead guide channel is tangent to the spiral line of the threaded raceway at one end of the first bead guide channel, the center line of the inner cavity of the second bead guide channel is tangent to the spiral line of the threaded raceway at one end of the second bead guide channel, the center line of the inner cavity of the first bead guide channel is not coplanar with the center line of the inner cavity of the second bead guide channel, and the center line of the outer shell of the first bead guide channel and the center line of the outer shell of the second bead guide channel are located in the same plane.

[0008] In at least one embodiment, the outer shell of the first bead guide channel and the outer shell of the second bead guide channel are parallel and extend along a straight line.

[0009] In at least one embodiment, 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.

[0010] In at least one embodiment, the arc channel includes a first arc channel and a second arc channel, and the curved pipe return device also includes a straight channel connecting the first arc channel and the second arc channel at the same time, and 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.

[0011] In at least one embodiment, the center lines of the outer shells of the curved pipe return device are located in the same plane, and / or,

[0012] The outer diameters of the curved pipe return device at various positions are the same.

[0013] In at least one embodiment, the pipe bend return device is integrally formed by a powder metallurgy process.

[0014] In at least one embodiment, the nut includes a first bead guide channel mounting groove and a second bead guide channel mounting groove that are parallel and extend in a straight line, and the first bead guide channel and the second bead guide channel are respectively installed therein.

[0015] In at least one embodiment, on the nut, a first transition surface is provided between the thread raceway and the first bead guide channel mounting groove, and a second transition surface is provided between the thread raceway and the second bead guide channel mounting groove.

[0016] In at least one embodiment, one end of the first bead guide channel and one end of the second bead guide channel have a bead guide opening, the side of the bead guide opening facing the nut has a bead guide plate, the side of the bead guide opening facing the screw has a guard plate, and the distance between the bottom edge of the bead guide 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 pair further includes a pressure plate, which presses one or more of the elbow return devices against the nut.

[0018] In the pipe bending return device, the center line of the inner cavity of the first guide bead channel and the center line of the inner cavity of the second guide bead channel are tangent to the spiral line of the threaded raceway, respectively, so that the movement of the ball is smoother. The center line of the outer shell of the first guide bead channel and the center line of the outer shell of the second guide bead channel are located in the same plane, and the outer shell of the guide bead channel and the installation groove of the guide bead channel in the nut can follow the common two-dimensional plane layout principle, which is more convenient to process and has strong compatibility of the pipe bending return device. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A schematic structural diagram of a ball screw pair with a three-dimensional circulation structure according to an embodiment of the present application is shown, which hides part of the structure of the nut.

[0020] Figure 2 Shows Figure 1 The nuts in the.

[0021] Figure 3 A schematic diagram of the helical lines of the curved tube return device and the thread raceway in the ball screw pair with a three-dimensional circulation structure according to an embodiment of the present application is shown.

[0022] Figure 4 Shows Figure 3 Front view of the curved pipe return device.

[0023] Figure 5 Shows Figure 4 A top view of the curved pipe return device, which also shows the inner cavity of the curved pipe return device.

[0024] Description of Reference Numerals

[0025] 100 Nut

[0026] 111 First guide bead channel installation slot

[0027] 112 Second guide bead channel installation slot

[0028] 120 Arc slot

[0029] 200 Screw

[0030] 300 Thread raceway

[0031] 310 Second transition surface

[0032] 400 elbow return device

[0033] 411 First Bead Guide Channel

[0034] 412 Second bead guide channel

[0035] 413 Bead opening

[0036] 414 Bead guide plate

[0037] 415 Guard Plate

[0038] 420 Arc Channel

[0039] 421 First Arc Channel

[0040] 422 Second Arc Channel

[0041] 430 Straight Channel

[0042] 500 Balls

[0043] 600 Platen DETAILED DESCRIPTION

[0044] The exemplary embodiments of the present application are described below with reference to the accompanying drawings. It should be understood that these specific descriptions are only used to teach those skilled in the art how to implement the present application, and are not intended to exhaust all possible methods of the present application, nor to limit the scope of the present application.

[0045] The present application provides a ball screw pair having a three-dimensional circulation structure (hereinafter sometimes referred to as "ball screw pair").

[0046] See also Figure 1 The ball screw pair may include a nut 100 , a screw 200 , a curved pipe return device 400 and a ball 500 .

[0047] A threaded raceway 300 is formed between the nut 100 and the lead screw 200 for the ball 500 to move. The ball 500 may be a common steel ball.

[0048] See also Figure 3 The bend return device 400 may include a first guide ball channel 411 and a second guide ball channel 412 installed on the nut 100 and separated in the axial direction and circumferential direction of the nut 100. Exemplarily, the ball 500 moves along the threaded raceway 300, enters the bend return device 400 from the first guide ball channel 411, enters the second guide ball channel 412 along the bend return device 400, and then enters the threaded raceway 300 at another axial position from the second guide ball channel 412, repeating the above actions to form a three-dimensional circulation structure. One or more bend return devices 400 may be installed in the ball screw pair.

[0049] The center lines of the outer shell of the elbow return device 400 can be located in the same plane. The elbow return device 400 can also include multiple inner cavities, the center lines of the multiple inner cavities are sequentially tangent, and the center lines of the multiple inner cavities are not coplanar. The center line of the inner cavity is also tangent to the helix (or thread line) of the threaded raceway 300.

[0050] Exemplarily, the center line of the inner cavity of the first bead guide channel 411 is tangent to the spiral line of the threaded raceway 300 at one end of the first bead guide channel 411, and the center line of the inner cavity of the second bead guide channel 412 is tangent to the spiral line of the threaded raceway 300 at one end of the second bead guide channel 412. The center line of the inner cavity of the first bead guide channel 411 is not coplanar with the center line of the inner cavity of the second bead guide channel 412, and the center line of the outer shell of the first bead guide channel 411 and the center line of the outer shell of the second bead guide channel 412 are located in the same plane.

[0051] The inventors know of a pipe bend return device, in which the center line of the inner cavity of the pipe bend return device and the center line of the outer shell are colinear. Since the two helical lines at different axial positions are not coplanar, if the center line of the inner cavity of the pipe bend return device is to be kept tangent to the helical line, the outer shape of the pipe bend return device needs to have a three-dimensional configuration, which is difficult to process. In addition, the structure of the corresponding mounting groove in the nut needs to adapt to the three-dimensional configuration of the pipe bend return device, which is difficult to process, difficult to verify, and high in cost.

[0052] On the one hand, in the present application, the design that the center line of the inner cavity of the first ball guide channel 411 and the center line of the inner cavity of the second ball guide channel 412 are tangent to the spiral line of the threaded raceway 300 can make the transition of the ball 500 between the threaded raceway 300 and the ball guide channel smoother, and the ball 500 can obtain a higher limit speed. Significant improvements have been achieved in terms of fluency, 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 bead guide channel 411 and the center line of the outer shell of the second bead guide channel 412 are located in the same plane, which means that the outer shell of the bead guide channel and the installation groove of the bead guide channel in the nut 100 can follow the common two-dimensional plane layout principle, which is more convenient to process and the bend return device 400 has strong compatibility.

[0054] That is, Figures 3 to 5 As shown, the inner cavity of the curved pipe return device 400 forms a three-dimensional configuration in which the center line is tangent to the spiral line, and the outer shell maintains a two-dimensional configuration in which the center line is in the same plane, which not only allows the ball to run smoothly but also reduces the difficulty of processing.

[0055] In one embodiment, see Figure 3 , Figure 4 The shell of the first bead guide channel 411 and the shell of the second bead guide channel 412 are parallel and extend in a straight line. Its shape is simple, so that the installation groove of the bead guide channel in the nut 100 can be simply set accordingly, reducing the processing cost.

[0056] In one embodiment, see Figure 3 , Figure 4 The 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 bend return device 400 also includes a straight channel 430 connecting the first arc channel 421 and the second arc channel 422, and 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 shell of the curved pipe return device 400 are located in the same plane, which is convenient for processing. Of course, it is also possible to make only the center lines of the two bead guide channels located in the same plane.

[0059] In one embodiment, the outer diameters of the bend return device 400 at various positions are the same, so that the installation slots in the nut 100 can be made of uniform size.

[0060] The inventors also know of a pipe bend return device, which is composed of multiple separate structures. For example, the guide column channel, the arc channel and the straight channel are set as multiple separate individuals, and then the multiple individuals are combined and connected to form a pipe bend return device. This design will form gaps at the connection parts of the components. When the ball is running at high speed in the pipe bend return device, it may cause the components in the pipe bend return device to loosen and vibrate, thereby interfering with the smoothness of the ball movement, increasing noise, and affecting the overall performance.

[0061] In one embodiment of the present application, the pipe bend return device 400 is integrally formed. Integral forming can reduce the dimensional error caused by the composition of multiple parts, ensure the accuracy of the channel, and overcome the above-mentioned problems. Exemplarily, the pipe bend return device 400 can be made by sintering stainless steel powder metallurgy, so that it has the characteristics of high hardness and strong load-bearing capacity.

[0062] In one embodiment, see Figure 2 The nut 100 includes a first bead guide channel installation groove 111 and a second bead guide channel installation groove 112 that are parallel and extend in a straight line. The first bead guide channel 411 and the second bead guide channel 412 are respectively installed therein. The installation groove has a simple shape and is easy to process.

[0063] Furthermore, the nut 100 may further include an arc groove 120 for accommodating the arc channel 420 .

[0064] In one embodiment, on the nut 100 , a first transition surface is provided between the thread raceway 300 and the first bead guide channel mounting groove 111 , and a second transition surface 310 is provided between the thread raceway 300 and the second bead guide channel mounting groove 112 .

[0065] It should be understood that the diameter of the inner cavity of the ball guide channel is generally larger than the raceway diameter of the threaded raceway 300. Therefore, setting a transition surface can make the ball 500 smoother when transitioning between the threaded raceway 300 and the ball guide channel, reducing jamming. Exemplarily, the transition surface can be a curved surface connected to the threaded raceway 300 and the ball guide channel mounting groove.

[0066] In one embodiment, see Figure 3 , Figure 4 One end of the first bead guide channel 411 and one end of the second bead guide channel 412 have a bead guide opening 413, the side of the bead guide opening 413 facing the nut 100 has a bead guide plate 414, and the side of the bead guide opening 413 facing the screw 200 has a guard plate 415, and the distance between the bottom edge of the bead guide plate 414 and the bottom edge of the guard plate 415 is not greater than the diameter of the ball 500, so as to prevent the ball 500 from falling.

[0067] In one embodiment, see Figure 1 The ball screw pair may further include a pressure plate 600, which presses one or more elbow return devices 400 against the nut 100. For example, after the elbow return device 400 is installed in the corresponding installation groove, the pressure plate 600 may be pressed against the upper part of the linear channel 430, and then the pressure plate 600 may be fixed to the nut 100 by screws. The pressure plate 600 may have a certain elasticity.

[0068] The above is a preferred embodiment of the present application. It should be pointed out that for those skilled in the art, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. A ball screw pair with a three-dimensional circulation structure, characterized in that: include: A nut (100) and a lead screw (200) are provided, wherein a threaded raceway (300) is formed between the nut (100) and the lead screw (200) for the ball (500) to move. A pipe bend return device (400) comprises a first bead guide channel (411) and a second bead guide channel (412) which are installed on the nut (100) and separated in the axial and circumferential directions of the nut (100), wherein the center line of the inner cavity of the first bead guide channel (411) is tangent to the helix of the threaded raceway (300) at one end of the first bead guide channel (411), and the center line of the inner cavity of the second bead guide channel (412) is tangent to the helix of the threaded raceway (300) at one end of the second bead guide channel (412). The center line of the inner cavity of the first bead guide channel (411) is not coplanar with the center line of the inner cavity of the second bead guide channel (412), and the center line of the outer shell of the first bead guide channel (411) and the center line of the outer shell of the second bead guide channel (412) are located in the same plane.

2. The ball screw pair with a three-dimensional circulation structure according to claim 1 is characterized in that: The outer shell of the first bead guiding channel (411) and the outer shell of the second bead guiding channel (412) are parallel and extend along a straight line.

3. The ball screw pair with a three-dimensional circulation structure according to claim 2 is characterized in that: The 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).

4. The ball screw pair with a three-dimensional circulation structure according to claim 3 is characterized in that: The circular arc channel (420) includes a first circular arc channel (421) and a second circular arc channel (422), and the curved pipe return device (400) further includes a straight channel (430) that simultaneously connects the first circular arc channel (421) and the second circular arc channel (422), and 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 circular arc channel (421) and the center line of the inner cavity of the second circular arc channel (422).

5. The ball screw pair with a three-dimensional circulation structure according to claim 1, characterized in that: The center lines of the outer shells of the curved pipe return device (400) are located in the same plane, and / or, The outer diameters of the curved pipe return device (400) at various positions are the same.

6. The ball screw pair with a three-dimensional circulation structure according to claim 1, characterized in that: The pipe bend return device (400) is integrally formed by a powder metallurgy process.

7. The ball screw pair with a three-dimensional circulation structure according to claim 2, characterized in that: The nut (100) comprises a first bead guide channel installation groove (111) and a second bead guide channel installation groove (112) which are parallel and extend in a straight line, and the first bead guide channel (411) and the second bead guide channel (412) are respectively installed therein.

8. The ball screw pair with a three-dimensional circulation structure according to claim 7, characterized in that: On the nut (100), a first transition surface is provided between the threaded raceway (300) and the first guide bead channel mounting groove (111), and a second transition surface (310) is provided between the threaded raceway (300) and the second guide bead channel mounting groove (112).

9. The ball screw pair with a three-dimensional circulation structure according to claim 1, characterized in that: One end of the first bead guide channel (411) and one end of the second bead guide channel (412) have a bead guide opening (413), the side of the bead guide opening (413) facing the nut (100) has a bead guide plate (414), the side of the bead guide opening (413) facing the lead screw (200) has a guard plate (415), and the distance between the bottom edge of the bead guide plate (414) and the bottom edge of the guard plate (415) is no greater than the diameter of the ball (500).

10. The ball screw pair with a three-dimensional circulation structure according to claim 1, characterized in that: The ball screw pair also includes a pressure plate (600), and the pressure plate (600) presses one or more of the curved pipe return devices (400) against and installs them on the nut (100).

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