Ball screw and brake
By designing a circulating raceway on the outer circumference of the screw, the reverse motion of the ball screw is realized, which solves the problem of needing an additional reverser in the existing technology, simplifies production and reduces costs.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SHANGHAI WATSON RALLY AUTOMOTIVE TECHNOLOGY CO LTD
- Filing Date
- 2024-12-31
- Publication Date
- 2026-06-30
AI Technical Summary
Existing ball screw mechanisms require an additional reversing device to reverse the ball rotation, resulting in complex manufacturing and high costs.
Design a ball screw structure that does not require an additional reverser. By setting a circulating raceway on the outer circumference of the screw, including a first raceway section and a second raceway section, the balls achieve reverse movement in the circulating channel. The first raceway section and the outer raceway form a transmission channel, and the second raceway section forms a non-transmission channel on its own. The balls return through the second raceway section when the nut rotates.
It achieves reverse ball movement without the need for additional parts, simplifying the production process and reducing costs.
Smart Images
Figure CN122305197A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to ball screws and brakes. Background Technology
[0002] Ball screws are a common type of transmission component. The balls transform the sliding friction generated when the screw rotates relative to the nut into rolling friction, thus reducing wear. Currently, most ball screw mechanisms require a reversing device to reverse and circulate the nut. The reversing device, mounted on one side of the nut, provides a return channel for the balls, allowing them to return to their initial position after rolling a certain distance, thus achieving cyclic rolling. Summary of the Invention
[0003] This invention provides a ball screw structure that can reverse the ball bearings without the need for a reversing device.
[0004] To achieve the above objectives, the present invention provides a ball screw, comprising:
[0005] The nut has a helical, continuous outer raceway on its inner circumferential surface.
[0006] The screw has multiple circulating raceways arranged along the screw axis on its outer peripheral surface, and the circulating raceways are circumferentially closed around the outer peripheral surface.
[0007] The circulating raceway has a first raceway section and a second raceway section, wherein,
[0008] The first raceway section is spiral-shaped and does not complete a full turn; the first raceway section is positioned opposite the outer raceway.
[0009] The second raceway section connects the two ends of the first raceway section. The second raceway section has a central recess that can fully accommodate the ball bearings. The two ends of the second raceway section form slopes that transition from the first raceway section to the central recess.
[0010] In the same circulating raceway, the first raceway section and the outer raceway form a transmission channel, and the second raceway section forms a separate non-transmission channel. The transmission channel and the non-transmission channel are connected end to end to form the ball circulation channel.
[0011] Multiple balls are arranged in a pattern within the circulation channel.
[0012] When the nut rotates relative to the screw, the screw is driven by the ball bearings located in the conventional channel. The ball bearings located at one end of the first raceway can return to the other end of the first raceway through the second raceway.
[0013] In some embodiments of the present invention, the first raceway section, which is less than one full turn, exceeds half a turn.
[0014] In some embodiments of the present invention, the screw has a tube wall portion, and the circulating raceway is formed on the outer peripheral surface of the tube wall portion by machining, wherein the first raceway section and the second raceway section are integrally connected.
[0015] In some embodiments of the present invention, the screw further includes an assembly portion, which is disposed inside the tube wall portion and connected to the inner circumferential surface of the tube wall portion. The assembly portion has an assembly hole along the central axial direction of the tube wall portion.
[0016] The present invention also relates to a brake, including a transmission mechanism, wherein the transmission mechanism includes any of the ball screws described above.
[0017] The present invention achieves the reversal of the ball bearings without the need for an additional reversing device, which has the advantages of convenient processing and low cost. Attached Figure Description
[0018] Figure 1 This is a schematic diagram of the structure of a ball screw.
[0019] Figure 2 This is a schematic diagram of the nut structure.
[0020] Figure 3 The image shows the balls on the surface of a screw machine.
[0021] Figure 4 This is a schematic diagram of the screw structure.
[0022] Figure 5 This is a schematic diagram of the cross-section of a ball screw.
[0023] Figure 6 for Figure 5 A magnified view of a portion of the image.
[0024] In the picture:
[0025] 1-Ball screw, 11-Transmission channel, 100-Nut, 110-Inner circumferential surface, 111-Outer raceway, 112-Thread, 200-Screw, 201-Outer circumferential surface, 210-Circulating raceway, 211-First raceway section, 212-Second raceway section, 220-Pipe wall section, 230-Assembly section, 231-Assembly hole, 300, 300a, 300b-Balls. Detailed Implementation
[0026] Given that existing ball screw structures require additional components to reverse the ball rotation, this invention provides a different ball screw structure that achieves reversal without additional components. The structure includes:
[0027] The nut has a helical, continuous outer raceway on its inner circumferential surface.
[0028] The screw has multiple circulating raceways arranged along the screw axis on its outer peripheral surface, and the circulating raceways are circumferentially closed around the outer peripheral surface.
[0029] The circulating raceway has a first raceway section and a second raceway section, wherein,
[0030] The first raceway section is spiral-shaped and does not complete a full turn; the first raceway section is positioned opposite the outer raceway.
[0031] The second raceway section connects the two ends of the first raceway section. The second raceway section has a central recess that can fully accommodate the ball bearings. The two ends of the second raceway section form slopes that transition from the first raceway section to the central recess.
[0032] In the same circulating raceway, the first raceway section and the outer raceway form a transmission channel, and the second raceway section forms a separate non-transmission channel. The transmission channel and the non-transmission channel are connected end to end to form the ball circulation channel.
[0033] Multiple balls are arranged in a pattern within the circulation channel.
[0034] When the nut rotates relative to the screw, the screw is driven by the ball bearings located in the conventional channel. The ball bearings located at one end of the first raceway can return to the other end of the first raceway through the second raceway.
[0035] In the above-mentioned ball screw structure, the balls return from the second raceway on the outer circumference of the screw, eliminating the need for additional parts to provide a reverse channel, which has the advantages of easy production and low cost.
[0036] The outer raceway contacts the balls from the outside and should have a certain depth so that the screw can be translated by the ball-driven nut during rotation. For example, the cross-sectional shape of the outer raceway can be a concave arc. Methods for forming a helical outer raceway on the inner circumference of the nut are known, such as through machining. In existing technology, several mounting holes are typically formed on the nut, and then a component containing a reverse passage, such as a reverser, is placed within these holes. The reverse passage bridges adjacent outer raceways, guiding the balls in the opposite direction. This invention does not do this. The outer raceway of this invention is continuous.
[0037] The circulating raceway contacts the balls from the inside. The circulating raceway should have a certain depth so that the balls roll within it when the screw rotates. For example, the cross-sectional shape of the circulating raceway can be a concave surface with a circular arc. The circulating raceway is annular and closed on the outer circumference of the screw, and includes two connected sections: a first raceway section and a second raceway section. The first raceway section is arranged in a spiral shape, not completing a full turn. The first raceway is positioned opposite the outer raceway to form a transmission channel. The balls located within this transmission channel participate in the transmission between the screw and the nut, thereby converting the screw's rotation into the axial translation of the nut. Preferably, the first raceway section exceeds half a turn to increase the total length of the transmission channel and improve transmission stability. The second raceway section connects the two ends of the first raceway section. The second raceway section has a central recess that can fully accommodate the ball. Both ends of the second raceway section form slopes transitioning from the first raceway section to the central recess. The second raceway section forms a separate non-transmission channel, allowing the ball to return from one end of the first raceway section to the other. When the ball is fully positioned within the second raceway section, it does not contact the outer raceway and therefore does not participate in the transmission between the screw and the nut. Thus, the transmission channel formed by the first raceway section and the outer raceway, and the non-transmission channel formed by the second raceway section, are connected end-to-end, forming a circular path for the ball's rolling. Since this invention has multiple circulating raceways, there are also multiple corresponding circulating paths in the ball screw. Methods for forming circulating raceways on the outer circumferential surface of the screw are known, such as machining, which is simple, does not require additional parts to provide a reverse channel, and has the advantage of low cost.
[0038] Figure 1 A ball screw based on the present invention is shown, which is used as a transmission mechanism in a brake, comprising a nut 100 and a screw 200, the nut being rotatably fitted over the screw. (Specific combination) Figure 2 The nut 100 has a tubular shape and a continuous spiral outer raceway 111 on its inner circumferential surface 100. Figure 3 The diagram shows the structure of the ball bearings 300 disposed on the screw 200. The surface of the screw 200 includes four independent circulating raceways 210, and multiple ball bearings 300 are arranged in the circulating raceways 210. Figure 4 This shows the structure of the screw 200, combined with Figure 5The screw 200 has a tube wall portion 220 and an assembly portion 230. The assembly portion 230 is disposed inside the tube wall portion 220 and connected to the inner circumferential surface of the tube wall portion 220. The assembly portion 230 has an assembly hole 231 along the central axial direction of the tube wall portion, in which a drive shaft can be fixed. The motor in the brake can then transmit torque to the drive shaft through a transmission gear, and the rotation of the drive shaft will drive the screw to rotate together. There are four circulating raceways 210 on the outer circumferential surface 201 of the tube wall portion 220. They are arranged sequentially along the axial direction of the screw 200. Each circulating raceway 210 includes a first raceway section 211 and a second raceway 212. The first raceway section 211 is less than one revolution. The second raceway section 212 connects the two ends of the first raceway section 211. The second raceway section has a central recess that can fully accommodate the ball, and the two ends form a slope that transitions from the first raceway section 211 to the central recess. Figure 6 for Figure 5 The enlarged view of part A shows the state of the ball when it is located in the first raceway section 211 and the second raceway section 212. The ball 300a is located in the recessed part in the center of the second raceway section 212. It can be seen that the ball 300a is now completely contained within the second raceway section 212 and is crossing the protruding thread 112 between the two adjacent outer raceways. As the screw 200 continues to rotate, the nut 100 is further translated to the left or right in the figure by the transmission. The ball 300a will then cross the thread 112 and enter the adjacent transmission channel 11 formed by the first raceway section 211 and the outer raceway 111, as shown by the ball 300b in the figure. In this way, the ball completes the return from one end to the other, realizing rolling in a cyclic path.
[0039] When the screw 200 rotates, the first raceway section 221 of the screw will be displaced axially, thereby exerting pressure on the balls. The balls, in turn, apply axial pressure to the surface of the outer raceway 111, pushing the nut to translate axially. Simultaneously, the balls themselves roll. When the ball 300 rotates to the end where the first raceway section 211 connects to the second raceway section 212, it enters the second raceway section 212 due to the compression between the first raceway section 211 and the outer raceway 111. The ball 300 crosses the thread 112 in the second raceway section 212, and due to the subsequent pushing force of the ball entering the second raceway section 212, it is pushed out to the other end where the first raceway section 211 connects to the second raceway section 212, thus completing the movement of the ball 300 from one end of the first raceway section to the other. Therefore, the ball 300 circulates within the circulation channel.
[0040] The embodiments described in this invention are for illustrative purposes only and do not constitute a limitation on the scope of the claims. Other substantially equivalent substitutions that can be conceived by those skilled in the art are all within the scope of protection of this invention.
Claims
1. Ball screw, characterized in that include: The nut has a helical, continuous outer raceway on its inner circumferential surface. The screw has multiple circulating raceways arranged along the screw axis on its outer peripheral surface, and the circulating raceways are circumferentially closed around the outer peripheral surface. The circulating raceway has a first raceway section and a second raceway section, wherein, The first raceway section is spiral-shaped and does not complete a full turn; the first raceway section is positioned opposite the outer raceway. The second raceway section connects the two ends of the first raceway section. The second raceway section has a central recess that can fully accommodate the ball bearings. The two ends of the second raceway section form slopes that transition from the first raceway section to the central recess. In the same circulating raceway, the first raceway section and the outer raceway form a transmission channel, and the second raceway section forms a separate non-transmission channel. The transmission channel and the non-transmission channel are connected end to end to form the ball circulation channel. Multiple balls are arranged in a pattern within the circulation channel. When the nut rotates relative to the screw, the screw is driven by the ball bearings located in the conventional channel. The ball bearings located at one end of the first raceway can return to the other end of the first raceway through the second raceway.
2. The ball screw as set forth in claim 1, wherein The first raceway section, which is less than one full turn, exceeds half a turn.
3. The ball screw as set forth in claim 1, wherein The screw has a tube wall portion, and the circulating raceway is formed on the outer circumferential surface of the tube wall portion by machining. The first raceway section and the second raceway section are integrally connected.
4. The ball screw as set forth in claim 3, wherein The screw also has an assembly part, which is disposed inside the tube wall and connected to the inner circumferential surface of the tube wall. The assembly part has an assembly hole along the central axis of the tube wall.
5. Brake comprising a transmission mechanism, characterized in that The transmission mechanism includes the ball screw as described in any one of claims 1 to 4.