Ball screw and brake

Abstract

The embodiment of the utility model provides a ball screw and a brake, and relates to the technical field of mechanical braking. The ball screw comprises a nut, a lead screw and a ball; one end of the nut is provided with a thread port; the lead screw comprises a lead screw body and a key shaft, the lead screw body is in threaded connection with the nut in the threaded opening, and the key shaft is connected with the lead screw body through an elastic piece. The ball is spirally wound around the lead screw and arranged between the lead screw and the nut. The key shaft bears part of axial force and torque, the stress burden of the lead screw part is relieved, then the additional bending moment borne by the lead screw and the key shaft in the rotating process is reduced, the lead screw and the key shaft are evenly stressed and not prone to deflection and abrasion, and therefore the service life of the lead screw is prolonged.

Description

Technical Field

[0001] This utility model relates to the field of mechanical braking technology, specifically to a ball screw and brake. Background Technology

[0002] The ball screw in a brake is a key mechanical transmission component that plays a vital role in the braking system. For example, ball screws are widely used in automotive braking systems.

[0003] A typical ball screw consists of a screw, a nut, and balls. The balls roll in the helical grooves of the screw and nut, and the rotational motion of the screw is converted into the linear motion of the nut, thereby pushing the brake caliper or brake shoe and other braking components closer to the brake disc to generate braking force.

[0004] The inventors discovered that traditional lead screws are cylindrical metal rods with helical grooves. When there is a misalignment in the connection between the lead screw and components such as the motor output shaft or brake caliper, the lead screw will be subjected to additional bending torque during rotation. This can easily cause uneven force on the lead screw, resulting in wobbling and wear, and thus shortening the service life of the lead screw. Utility Model Content

[0005] The purpose of this utility model is to provide a ball screw and brake that can solve the problem of uneven force on the ball screw caused by additional bending torque, resulting in wobbling and wear.

[0006] The embodiments of this utility model can be implemented as follows:

[0007] On one hand, this application provides a ball screw, including a nut with a threaded opening at one end; a screw, the screw including a lead rod and a key shaft, the lead rod being threadedly connected to the nut in the threaded opening, the key shaft being connected to the lead rod through an elastic element; and balls, spirally wound around the lead rod and disposed between the lead rod and the nut.

[0008] This configuration splits the lead screw into two parts, forming a key shaft and a lead rod. The key shaft and lead rod are connected by an elastic element, allowing the key shaft to bear a portion of the axial force and torque, reducing the stress on the lead rod. This, in turn, reduces the additional bending moment experienced by the lead rod and key shaft during rotation, resulting in more even stress distribution on the lead rod and key shaft, reducing wear and tear, and thus increasing the service life of the lead screw.

[0009] Optionally, the key shaft passes through the lead screw along the axial direction of the lead screw, and an annular groove is provided at one end of the key shaft passing through the lead screw. The elastic element includes an elastic retaining ring that is locked in the annular groove. The elastic retaining ring is used to restrict the relative rotation of the key shaft and the lead screw and to restrict axial disengagement.

[0010] This design allows for a detachable connection between the lead screw and the key shaft. Furthermore, when the lead screw and key shaft are subjected to additional axial and radial bending moments, the elastic force of the retaining ring can reduce the stress concentration factor, thereby reducing defects such as fatigue cracks caused by stress concentration and ultimately reducing wear on the lead screw and key shaft.

[0011] Optionally, the lead screw has a partition inside, and the partition has a snap-fit ​​groove for the end of the key shaft to pass through. The end of the key shaft has a snap-fit ​​block that snaps into the snap-fit ​​groove.

[0012] This design allows for precise positioning of the lead screw and key shaft during installation, making it easier to keep the axis of the lead screw and the axis of the key shaft concentric. On the other hand, it restricts the relative rotation of the key shaft and the lead screw, maintaining the stability of the power transmission between them.

[0013] Optionally, the key shaft also has an arc-shaped portion located on the side of the snap-fit ​​block away from the elastic retaining ring, and the partition plate has an arc-shaped groove communicating with the snap-fit ​​groove, the arc-shaped groove being accommodated by the arc-shaped portion.

[0014] This design increases the contact area between the key shaft end and the lead screw, effectively preventing slippage during torque transmission.

[0015] Optionally, the key shaft has a force-bearing ring plate located outside the lead screw, and the force-bearing ring plate and the lead screw are coaxial.

[0016] This configuration enhances the axial rigidity of the key shaft and lead screw when subjected to large braking forces, effectively reducing axial deformation of the lead screw and key shaft.

[0017] Optionally, the end face of the lead screw located inside the lead nut is provided with an abutment block, and the lead nut is provided with a limiting block. The side wall of the abutment block in the radial direction of the lead screw abuts against the side wall of the limiting block in the radial direction of the lead nut.

[0018] This configuration, through the contact of the abutment block and the limiting block, prevents the nut from contacting the end face of the lead screw and getting stuck, thus protecting the nut and the lead screw.

[0019] Optionally, the ball screw further includes a reverser disposed on the circumferential sidewall of the screw, the reverser connecting two adjacent threaded tracks on the screw to form a loop for the balls to roll.

[0020] This design allows the balls to circulate smoothly between the threaded tracks of the lead screw and the nut, preventing the balls from stopping or slipping when they reach the end of the nut, reducing the coefficient of friction, reducing energy loss during transmission, and thus improving the transmission efficiency of the ball screw.

[0021] Optionally, an anti-rotation groove is provided on the outer wall of the nut, and the anti-rotation groove extends along the axial direction of the nut.

[0022] This configuration is intended to limit the nut in the radial direction, allowing it to move axially as the lead screw rotates.

[0023] Optionally, the end of the key shaft away from the lead screw has the spline, which is used to transmit torque.

[0024] This configuration ensures high-precision alignment between the key shaft and the connected drive components (such as motor shafts) in both the axial and circumferential directions, improving the efficiency and reliability of torque transmission.

[0025] On the other hand, this application also provides a brake, including a ball screw as described in the first aspect.

[0026] The beneficial effects of the ball screw and brake provided in this embodiment of the utility model include:

[0027] (1) The spline shaft and the lead screw are flexibly connected, which can solve the problems of common runout wear and uneven force when the spline shaft and the lead screw are rigidly connected;

[0028] (2) The elastic force of the elastic retaining ring reduces the stress concentration factor, reduces defects such as fatigue cracks caused by stress concentration, and thus reduces the wear on the lead screw and key shaft.

[0029] (3) The arc groove and arc section increase the contact area between the key shaft end and the lead screw, effectively preventing slippage during torque transmission. Attached Figure Description

[0030] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this utility model and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a cross-sectional structural diagram of the ball screw portion provided in this embodiment;

[0032] Figure 2 This is an exploded view of the ball screw provided in this embodiment;

[0033] Figure 3 This is a cross-sectional schematic diagram of the lead screw provided in this embodiment.

[0034] Icons: 1-Ball screw; 11-Nut; 111-Threaded opening; 112-Limit block; 113-Anti-rotation groove; 12-Screw; 121-Screw rod; 1211-Baffle plate; 1212-Snap-fit ​​groove; 1213-Arc groove; 122-Key shaft; 1221-Ring groove; 1222-Snap-fit ​​block; 1223-Arc section; 1224-Force-bearing ring plate; 1225-Positioning ring plate; 1226-Spline; 123-Abutment block; 13-Ball; 14-Elastic element; 141-Elastic retaining ring; 15-Reversing device. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. The components of the embodiments of this utility model described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0036] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0037] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0038] In the description of this utility model, it should be noted that if terms such as "upper," "lower," "inner," or "outer" are used to indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the utility model product is usually placed during use, they are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0039] Furthermore, the terms "first" and "second" are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0040] It should be noted that, where there is no conflict, the features in the embodiments of this utility model can be combined with each other.

[0041] As described in the background section, the ball screw in an electromechanical brake primarily works in conjunction with a reduction gear to reduce the output torque of the motor, amplifying the braking force so that the braking system can generate sufficient braking torque to slow down or stop the vehicle. As the nut moves linearly, the connected brake caliper is pushed, causing the friction pads on the caliper to contact the brake disc and generate friction. This friction creates a braking torque, preventing the wheels from rotating, thus slowing down or stopping the vehicle. Traditional ball screws are cylindrical metal rods with helical grooves. When there is a misalignment in the connection between the ball screw and components such as the motor output shaft or brake caliper, the ball screw is subjected to additional bending torque during rotation, easily leading to uneven stress and wear, resulting in a shortened service life.

[0042] To address these issues, this application provides a ball screw and brake. The ball screw and brake provided by this utility model are described in detail below with reference to the embodiments and accompanying drawings. It should be noted that the order of description of the embodiments is not intended to limit the preferred order of the embodiments.

[0043] Please see Figure 1 , Figure 1 This is a cross-sectional structural diagram of the ball screw provided in this embodiment. The ball screw 1 includes a nut 11, a screw 12, and balls 13. One end of the nut 11 has a threaded opening 111, and the other end has an end face. The screw 12 includes a lead rod 121 and a key shaft 122. The lead rod 121 is threadedly connected to the nut 11 within the threaded opening 111. The key shaft 122 is connected to the lead rod 121 via an elastic element 14. The balls 13 are spirally wound around the lead rod 121 and disposed between the lead rod 121 and the nut 11.

[0044] In this embodiment, the number of threads inside the nut 11 is greater than the number of threads on the lead screw 121. The diameter of the key shaft 122 is smaller than the diameter of the lead screw 121, and the length of the key shaft 122 is greater than the length of the lead screw 121. The key shaft 122 transmits driving force to the lead screw 121 through a connecting drive component (such as a motor). The lead screw 121 then rotates, and through the threaded connection, the nut 11 slides along the axial direction of the lead screw 121.

[0045] In some embodiments, see Figure 1 and Figure 2 , Figure 2 This is an exploded view of the ball screw 1 provided in this embodiment. The key shaft 122 passes through the screw 121 along its axial direction. The ball screw 1 also includes a reverser 15. The reverser 15 is disposed on the circumferential sidewall of the screw 121. The reverser 15 connects two adjacent threaded tracks on the screw 121 to form a circulation loop for the balls 13 to roll.

[0046] In this embodiment, the reverser 15 is embedded in the side wall of the lead screw 121. Multiple reversers 15 are arranged along the axial direction of the lead screw 121, and each reverser 15 is staggered in the axial direction of the lead screw 121. The reverser 15 has a groove for the rolling of the ball 13. The groove is inclined, and the inclined groove connects two adjacent threaded tracks to form a circulating loop for the rolling of the ball 13.

[0047] In some embodiments, continue reading Figure 1 The end face of the lead screw 121 located inside the lead screw nut 11 is provided with an abutment block 123. The lead screw nut 11 is provided with a limiting block 112. The side wall of the abutment block 123 in the radial direction of the lead screw 121 abuts against the side wall of the limiting block 112 in the radial direction of the lead screw nut 11.

[0048] Specifically, the limiting block 112 is located on the end face of the nut 11 facing the lead screw 121, and the limiting block 112 is located on the rotation path of the abutment block 123 as the lead screw 121 rotates, so that after the nut 11 is slidably sleeved onto the lead screw 121, the abutment of the abutment block 123 and the limiting block 112 prevents the end cap of the nut 11 from directly contacting the end face of the lead screw 121, so as to prevent the nut 11 and the lead screw 121 from jamming.

[0049] For example, an anti-rotation groove 113 is provided on the outer wall of the wire nut 11. The anti-rotation groove 113 extends along the axial direction of the wire nut 11 to limit the wire nut 11 in the radial direction.

[0050] Further, see 1 and Figure 2 The key shaft 122 has an annular groove 1221 at one end passing through the lead screw 121. The elastic element 14 includes an elastic retaining ring 141 that is locked in the annular groove 1221. The elastic retaining ring 141 is used to limit the relative rotation of the key shaft 122 and the lead screw 121 and to limit axial disengagement.

[0051] In this embodiment, the key shaft 122 and the lead screw 121 are coaxial. An elastic retaining ring 141 secures one end of the key shaft 122 passing through the lead screw 121, thus fixing the key shaft 122 and the lead screw 121 and achieving an elastic connection between them. It should be noted that the diameter of the key shaft 122 located within the annular groove 1221 is larger than the diameter of the elastic retaining ring 141, and the elastic retaining ring 141 has a notch. That is, the elastic retaining ring 141 is not a complete circle; this notch allows the elastic retaining ring 141 to have a radial tightening force, thereby securing the bottom of the annular groove 1221 of the key shaft 122.

[0052] In some embodiments, see Figure 2 and Figure 3 , Figure 3This is a cross-sectional view of the lead screw 121 provided in this embodiment. The lead screw 121 has a partition 1211 inside, and the partition 1211 has a snap-fit ​​groove 1212 for the end of the key shaft 122 to pass through. The end of the key shaft 122 has a snap-fit ​​block 1222 that snaps into the snap-fit ​​groove 1212.

[0053] In this embodiment, the lead screw 121 is hollow inside, and the partition 1211 divides the inside of the lead screw 121 into two chambers. The chamber inside the lead screw 121 that is closer to the end face of the lead nut 11 is smaller than the chamber that is farther away from the end face of the lead nut 11, and the radial range of the chamber that is closer to the end face of the lead nut 11 is smaller than the radial range of the chamber that is farther away from the end face of the lead nut 11, so as to increase the length of the key shaft 122 that passes through the lead screw 121.

[0054] For example, the snap-fit ​​groove 1212 and the snap-fit ​​block 1222 may be hexagonal in shape to position the key shaft 122 and the lead screw 121 axially by snapping the snap-fit ​​block 1222 and the snap-fit ​​groove 1212, while restricting the key shaft 122 and the lead screw 121 from rotating relative to each other.

[0055] Furthermore, the key shaft 122 also has an arc-shaped portion 1223, which is located on the side of the snap block 1222 away from the elastic retaining ring 141. The partition plate 1211 has an arc-shaped groove 1213 that communicates with the snap groove 1212, and the arc-shaped groove 1213 is used to accommodate the arc-shaped portion 1223.

[0056] It should be noted that the radial range of the arc-shaped groove 1213 on the partition 1211 is larger than the radial range of the snap-fit ​​groove 1212, and the snap-fit ​​groove 1212 is closer to the end face of the nut 11 than the arc-shaped groove 1213. The arc-shaped area of ​​the arc-shaped portion 1223 is larger than the arc-shaped area of ​​the arc-shaped groove 1213, and the groove width of the annular groove 1221 is larger than the elastic retaining ring 141. Moreover, when the snap-fit ​​block 1222 is engaged in the snap-fit ​​groove 1212 and the arc-shaped portion 1223 abuts against the arc-shaped groove 1213, a small portion of the annular groove 1221 is located within the snap-fit ​​groove 1212. Through the fit between the arc-shaped portion 1223 and the arc-shaped groove 1213, the elastic retaining ring 141 clamps the annular groove 1221 toward the groove wall of the arc-shaped portion 1223 and the side wall of the partition 1211 toward the retaining ring, thereby restricting the axial disengagement and relative rotation of the key shaft 122 and the lead screw 121.

[0057] Furthermore, the key shaft 122 has a force-bearing ring plate 1224 and a positioning ring plate 1225. The force-bearing ring plate 1224 is located outside the lead screw 121, and the positioning ring plate 1225 is located inside the lead screw 121. The force-bearing ring plate 1224, the positioning ring plate 1225, and the lead screw 121 are coaxial. The diameter of the force-bearing ring plate 1224 is smaller than the diameter of the positioning ring plate 1225, and the positioning ring plate 1225 is connected to the arc-shaped portion 1223 and abuts against the inner wall of the lead screw 121.

[0058] During the installation of the key shaft 122 and the lead screw 121, they are first snapped together by the snap-fit ​​block 1222 and the snap-fit ​​groove 1212, and then the arc-shaped part 1223 fits into the arc-shaped groove 1213, thereby causing the positioning ring plate 1225 to abut against the inner wall of the lead screw 121, further increasing the contact area between the key shaft 122 and the lead screw 121, thereby enhancing the connection stability between the key shaft 122 and the lead screw 121.

[0059] Furthermore, the end of the key shaft 122 away from the lead screw 121 has a spline 1226, which is used to transmit torque.

[0060] An embodiment of this utility model also provides a brake, including the aforementioned ball screw 1, as well as a motor, a brake caliper, and a brake disc. The motor drives the ball screw 12, causing the brake caliper to contact the brake disc. Under the friction of the friction pads of the brake caliper, the friction force is converted into braking torque, causing the wheel to decelerate or stop.

[0061] Therefore, the brake includes a ball screw 1, which has all the functions of a ball screw 1.

[0062] The above description is only a specific embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this utility model should be included within the protection scope of this utility model.

Claims

1. A ball screw, characterized by, The application relates to a ball screw (1) comprising: a nut (11) having a threaded hole (111) at one end; a screw rod (12) comprising a screw shaft (121) and a key shaft (122), the screw shaft (121) being screwed into the threaded hole (111) of the nut (11), and the key shaft (122) being connected to the screw shaft (121) through an elastic member (14); a plurality of balls (13) spirally wound around the screw shaft (121) and arranged between the screw shaft (121) and the nut (11).

2. The ball screw according to claim 1, characterized by The key shaft (122) penetrates the screw shaft (121) along the axial direction of the screw shaft (121), and a ring groove (1221) is formed at one end of the screw shaft (121) through which the key shaft (122) penetrates, the elastic member (14) comprises an elastic retainer ring (141) clamped in the ring groove (1221), and the elastic retainer ring (141) is used for limiting the relative rotation and axial disengagement of the key shaft (122) and the screw shaft (121).

3. The ball screw according to claim 2, characterized in that, The screw shaft (121) has a partition plate (1211) inside, the partition plate (1211) is provided with a clamping groove (1212) through which the end of the key shaft (122) penetrates, and the end of the key shaft (122) is provided with a clamping block (1222) clamped in the clamping groove (1212).

4. The ball screw according to claim 3, characterized in that, The key shaft (122) is further provided with an arc-shaped portion (1223) located on the side of the clamping block (1222) away from the elastic retainer ring (141), the partition plate (1211) is provided with an arc-shaped groove (1213) in communication with the clamping groove (1212), and the arc-shaped groove (1213) is used for accommodating the arc-shaped portion (1223).

5. The ball screw of claim 1, wherein, The key shaft (122) is provided with a force ring plate (1224) located outside the screw shaft (121), and the force ring plate (1224) and the screw shaft (121) are coaxial.

6. The ball screw of claim 1, wherein, The end face of the screw shaft (121) located in the nut (11) is provided with an abutting block (123), the nut (11) is provided with a limiting block (112), and the side wall of the abutting block (123) in the radial direction of the screw shaft (121) abuts against the side wall of the limiting block (112) in the radial direction of the nut (11).

7. The ball screw of claim 1, wherein The ball screw (1) further comprises a reverser (15) arranged on the circumferential side wall of the screw shaft (121), the reverser (15) communicates two adjacent thread tracks on the screw shaft (121) to form a circulating loop for the balls (13) to roll.

8. The ball screw according to any one of claims 1 to 7, characterized in that A rotation-preventing groove (113) is formed in the outer wall of the nut (11) and extends along the axial direction of the nut (11).

9. The ball screw according to any one of claims 1 to 7, characterized in that, The end of the key shaft (122) away from the screw shaft (121) is provided with a spline (1226) used for transmitting torque.

10. A brake characterized by The application further relates to a ball screw comprising any one of claims 1-9.

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