Ball screw and brake

Abstract

The utility model relates to a ball screw and a brake, the inner circumferential surface of a nut of the ball screw is provided with a spiral continuous outer raceway, the outer circumferential surface of a screw is provided with a plurality of circulating raceways arranged along the axial direction of the screw, each circulating raceway is provided with a first raceway section and a second raceway section, and the first raceway section and the outer raceway form a transmission channel. The second raceway section independently forms a non-transmission channel, the transmission channel and the non-transmission channel are communicated end to end to form a circulating channel of the balls, the multiple balls are arranged in the circulating channel in an arrayed mode, and when the nut rotates relative to the screw, the screw and the nut conduct transmission through the balls located in the transmission channel. The balls located at one end of the first raceway can return to the other end of the first raceway through the second raceway. The ball screw is used as a transmission mechanism in the brake. The utility model has the beneficial effects of convenient processing and low cost.

Description

Technical Field

[0001] The utility model relates to a ball screw and a brake. Background Art

[0002] Ball screws are a common transmission component. The balls convert the sliding friction generated by the screw relative to the nut into rolling friction, reducing losses. Currently, most ball screw mechanisms require a reverser to achieve reverse rotation and recirculation of the nut. The reverser, mounted on one side of the nut, provides a return channel for the balls. After rolling a certain distance, the balls return to their original position through this channel, achieving recirculation. Utility Model Content

[0003] The utility model provides a ball screw structure which can realize ball reversal without adding a reverser.

[0004] In order to achieve the above object, the utility model provides a ball screw, comprising:

[0005] Nut, the inner circumference of the nut has a spiral continuous outer raceway,

[0006] The outer peripheral surface of the screw has a plurality of circulating raceways arranged along the axial direction of the screw, and the circulating raceways are closed in an annular direction 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 and less than one turn, and the first raceway section is arranged opposite to the outer raceway.

[0009] The second raceway segment is connected to both ends of the first raceway segment. The center of the second raceway segment has a concave portion that can completely accommodate the balls. Both ends of the second raceway segment form a slope that transitions from the first raceway segment to the central concave portion.

[0010] In the same circulating raceway, the first raceway segment and the outer raceway form a transmission channel, the second raceway segment alone forms a non-transmission channel, and the transmission channel and the non-transmission channel are connected end to end to form a circulation channel for the balls.

[0011] A plurality of balls are arranged in the circulation channel.

[0012] When the nut rotates relative to the screw, the screw transmits the power to the nut through the balls located in the conventional channel, and the balls 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 segment which is less than one turn is more than half a turn.

[0014] In some embodiments of the present invention, the screw has a tube wall portion, the circulating raceway is formed on the outer circumference of the tube wall portion by machining, and the first raceway segment and the second raceway segment are integrally connected.

[0015] In some embodiments of the present invention, the screw further has an assembly portion, which is arranged in the tube wall portion and connected to the inner circumference of the tube wall portion. The assembly portion has an assembly hole opened along the central axis of the tube wall portion.

[0016] The utility model also relates to a brake, comprising a transmission mechanism, wherein the transmission mechanism comprises any one of the above-mentioned ball screws.

[0017] The utility model can realize the reversal of the ball without the need for an additional reversing device, and has the beneficial effects of convenient processing and low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Schematic diagram of the ball screw structure.

[0019] Figure 2 Schematic diagram of the structure of the nut.

[0020] Figure 3 Shown are balls on the surface of the screw machine.

[0021] Figure 4 Schematic diagram of the screw structure.

[0022] Figure 5 A cross-sectional diagram of a ball screw.

[0023] Figure 6 for Figure 5 A partial enlarged schematic diagram.

[0024] In the picture:

[0025] 1-ball screw, 11-transmission channel, 100-nut, 110-inner circumference, 111-outer raceway, 112-screw thread, 200-screw, 201-outer circumference, 210-circulating raceway, 211-first raceway segment, 212-second raceway segment, 220-tube wall, 230-assembly portion, 231-assembly hole, 300, 300a, 300b-balls. DETAILED DESCRIPTION

[0026] In view of the fact that existing ball screw structures require additional parts to achieve the reversal of the balls, the present invention provides a ball screw structure with a different structure, in which the reversal of the ball screw can be achieved without the need for additional parts. The structure includes:

[0027] Nut, the inner circumference of the nut has a spiral continuous outer raceway,

[0028] The outer peripheral surface of the screw has a plurality of circulating raceways arranged along the axial direction of the screw, and the circulating raceways are closed in an annular direction 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 and less than one turn, and the first raceway section is arranged opposite to the outer raceway.

[0031] The second raceway segment is connected to both ends of the first raceway segment. The center of the second raceway segment has a concave portion that can completely accommodate the balls. Both ends of the second raceway segment form a slope that transitions from the first raceway segment to the central concave portion.

[0032] In the same circulating raceway, the first raceway segment and the outer raceway form a transmission channel, the second raceway segment alone forms a non-transmission channel, and the transmission channel and the non-transmission channel are connected end to end to form a circulation channel for the balls.

[0033] A plurality of balls are arranged in the circulation channel.

[0034] When the nut rotates relative to the screw, the screw transmits the power to the nut through the balls located in the conventional channel, and the balls 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 are returned via the second raceway on the outer peripheral surface of the screw rod, and no additional parts for providing a reverse channel are required, which has the advantages of easy production and low cost.

[0036] The outer raceway contacts the balls from the outside, and the outer raceway should have a certain depth so that when the screw is rotating, it can be translated through the ball transmission nut. For example, the cross-sectional shape of the outer raceway can be a concave arc. The method of forming a spiral outer raceway on the inner circumference of a nut is known, and it can be formed by machining. In the prior art, a number of mounting holes are generally opened on the nut, and then a part containing a reverse passage, such as a reverser, is arranged in the mounting hole. The reverse passage spans between adjacent outer raceways to guide the balls in reverse direction. However, this is not done in the present invention. The outer raceway of the present invention is continuous.

[0037] The circulating raceway contacts the balls from the inside, and the circulating raceway should have a certain depth so that when the screw rotates, the balls roll in the circulating raceway. For example, the cross-sectional shape of the circulating raceway can be a concave surface with an arc-shaped cross-section. The circulating raceway is annular and closed on the outer peripheral surface of the screw, and includes two sections connected end to end: a first raceway section and a second raceway section. The first raceway section is arranged in a spiral shape for less than one circle, and the first raceway is arranged opposite to the outer raceway to form a transmission channel for transmission. The balls located in the transmission channel participate in the transmission between the screw and the nut, thereby converting the rotation of the screw into an axial translation of the nut. Preferably, the first raceway section exceeds half a circle to increase the total length of the transmission channel and improve the stability of the transmission. The second raceway section connects the two ends of the first raceway section. The center of the second raceway section has a recessed portion that can completely accommodate the balls. The two ends of the second raceway section form a slope that transitions from the first raceway section to the central recessed portion. The second raceway section forms a non-transmission channel alone, and the balls can return from one end of the first raceway section to the other end through the second raceway section. When the balls are completely located in the second raceway section, they do not contact the outer raceway and therefore do not participate in the transmission of the screw and 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 alone are connected end to end to form a circulation path for the balls to roll. In combination with the multiple circulation raceways in the present invention, there are also corresponding multiple circulation paths in the ball screw. The method of forming a circulation raceway on the outer circumference of the screw is known. For example, it can be formed by mechanical processing. The processing method is simple and does not require additional parts to provide a reverse channel, which has the advantage of low cost.

[0038] Figure 1 The figure shows a ball screw according to the present invention, which is used as a transmission mechanism in a brake, and includes a nut 100 and a screw 200, wherein the nut is rotatably sleeved on the screw. Figure 2 The main body of the nut 100 is in the shape of a tube, and has a continuous spiral outer raceway 111 on its inner circumference 100. Figure 3 The structure diagram of the balls 300 arranged on the screw 200 is shown. The surface of the screw 200 includes four independent circulation raceways 210, and a plurality of balls 300 are arranged in the circulation raceways 210. Figure 4 The structure of the screw 200 is shown, combined with Figure 5The screw 200 comprises a tube wall portion 220 and an assembly portion 230. The assembly portion 230 is disposed within the tube wall portion 220 and connected to the inner circumference of the tube wall portion 220. The assembly portion 230 has an assembly hole 231 formed along the central axis of the tube wall portion. A drive shaft can be fixed in the assembly hole 231. The motor in the brake can then transmit torque to the drive shaft via a transmission gear, and the rotation of the drive shaft then drives the screw to rotate. Four recirculating raceways 210 are arranged on the outer circumference 201 of the tube wall portion 220. They are arranged in sequence along the axial direction of the screw 200. Each recirculating raceway 210 includes a first raceway segment 211 and a second raceway segment 212. The first raceway segment 211 is less than one turn, and the second raceway segment 212 connects the two ends of the first raceway segment 211. The second raceway segment has a central recessed portion that can fully accommodate the balls, and slopes are formed at both ends to transition from the first raceway segment 211 to the central recessed portion. Figure 6 for Figure 5 The enlarged view of section A in the middle shows the state of the balls respectively located in the first raceway section 211 and the second raceway section 212. Ball 300a is located in the recessed portion at the center of the second raceway section 212. It can be seen that ball 300a is now completely contained within the second raceway section 212 and is straddling the raised thread 112 between the two adjacent outer raceway sections. As the screw 200 continues to rotate, the nut 100 is driven to further translate to the left or right in the figure, and ball 300a will straddle 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 ball 300b in the reference figure. The ball thus completes its return from one end to the other, achieving rolling in a circular path.

[0039] As the screw 200 rotates, the first raceway segment 221 of the screw moves axially, exerting pressure on the balls. The balls, in turn, exert axial pressure on the surface of the outer raceway 111, pushing the nut axially. Simultaneously, the balls themselves roll. When the balls 300 reach the junction of the first and second raceway segments 211 and 212, they are squeezed by the first and outer raceway segments 211 and enter the second raceway segment 212. There, the balls 300 cross the thread 112 and, subsequently pushed by the balls forced into the second raceway segment 212, are pushed to the other junction of the first and second raceway segments 211 and 212, completing their return motion from one end of the first raceway segment to the other. Thus, the balls 300 circulate within the circulation channel.

[0040] The embodiments of the present invention are only used to illustrate the present invention and do not limit the scope of the claims. Other substantially equivalent alternatives that can be thought of by those skilled in the art are all within the protection scope of the present invention.

Claims

1. Ball screw, characterized by include: Nut, the inner circumference of the nut has a spiral continuous outer raceway, The outer peripheral surface of the screw has a plurality of circulating raceways arranged along the axial direction of the screw, and the circulating raceways are closed in an annular direction 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 and less than one turn, and the first raceway section is arranged opposite to the outer raceway. The second raceway segment is connected to both ends of the first raceway segment. The center of the second raceway segment has a concave portion that can completely accommodate the balls. Both ends of the second raceway segment form a slope that transitions from the first raceway segment to the central concave portion. In the same circulating raceway, the first raceway segment and the outer raceway form a transmission channel, the second raceway segment alone forms a non-transmission channel, and the transmission channel and the non-transmission channel are connected end to end to form a circulation channel for the balls. A plurality of balls are arranged in the circulation channel. When the nut rotates relative to the screw, the screw transmits the power to the nut through the balls located in the conventional channel, and the balls 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 according to claim 1, characterized in that The first raceway section which is less than one turn is more than half a turn.

3. The ball screw according to claim 1, wherein The screw has a tube wall portion, and the circulating raceway is formed on the outer circumference of the tube wall portion by machining, and the first raceway segment and the second raceway segment are connected in one piece.

4. The ball screw according to claim 3, characterized in that The screw rod further comprises an assembly portion, which is arranged in the tube wall portion and connected to the inner circumference of the tube wall portion. The assembly portion is provided with an assembly hole along the central axis of the tube wall portion.

5. A brake, including a transmission mechanism, characterized in that The transmission mechanism includes the ball screw according to any one of claims 1 to 4.

Images