Electromechanical brake ball screw structure

Abstract

The utility model relates to a wire control brake technology field, concretely relates to a kind of electronic mechanical brake ball screw structure, comprising: caliper body, caliper body has a cylinder hole;Ball screw assembly is installed in cylinder hole, ball screw includes screw, nut, steel ball, nut is set in the outside of screw, and outside surface is equipped with rotation-stopping block, limit the circumferential movement of nut, the outer surface of screw is equipped with circulation channel, multiple steel balls are filled in circulation channel, and roll along circulation channel, to promote the linear motion of nut along cylinder hole axis, in the utility model, adopt the design of screw outer circulation channel and nut rotation-stopping block, avoid the complex structure of traditional nut slot installation reverser, simplify manufacturing process, reduce production cost, reduce stress concentration.

Description

Technical Field

[0001] This utility model relates to the field of brake-by-wire technology, and in particular to a ball screw structure for an electromechanical brake. Background Technology

[0002] In the field of automotive braking technology, electromechanical brakes, as an emerging braking method, are gradually demonstrating their significant advantages over traditional hydraulic braking systems. Electromechanical brakes achieve braking operation through motor drive, offering not only fast response and high control precision, but also easy integration with other vehicle electronic systems, providing a more flexible and efficient solution for intelligent driving and vehicle dynamics control. Among these components, the ball screw structure, as the core transmission component of the electromechanical brake, directly affects the overall efficiency and reliability of the brake.

[0003] Currently, some progress has been made in the research and development of electromechanical brakes. For example, the brake designs disclosed in patents CN117104205B and CN119099574A both adopt a dry brake caliper structure and use a ball screw to realize the conversion from rotation to linear motion in order to drive the brake pads to complete the clamping action.

[0004] The ball screw mentioned in the aforementioned patent employs a nut-circulation method, where the balls circulate between the nut and the screw to achieve continuous transmission. However, this design requires specialized grooves on the nut to house a reversing mechanism to guide the ball's circulation path. This design not only increases the machining difficulty and manufacturing cost of the nut but also makes the entire ball screw system relatively complex, hindering assembly and maintenance. The grooved design of the nut leads to increased local line contact stress. Under long-term high-load operation, this stress concentration can easily cause fatigue damage to the nut surface, such as the generation and propagation of cracks, thus affecting the overall service life of the ball screw and the reliability of the brake. Furthermore, while using pins to fix the nut for anti-rotation is simple and easy, fretting wear between the pin and the nut can also become a potential failure mode under high-frequency vibration and impact loads.

[0005] Therefore, this application develops an electromechanical brake ball screw structure to solve the problems existing in the prior art. Utility Model Content

[0006] The purpose of this invention is to provide a ball screw structure for an electromechanical brake, so as to solve the problem of complex structure caused by the use of a ball screw loop in the prior art.

[0007] The technical solution of this utility model is: an electromechanical brake ball screw structure, comprising:

[0008] A caliper body having a cylinder bore;

[0009] A ball screw assembly is installed inside the cylinder bore. The ball screw includes a screw, a nut, and steel balls. The nut is sleeved outside the screw, and an anti-rotation block is installed on its outer surface to restrict the circumferential movement of the nut. The outer surface of the screw is provided with a circulation channel, and multiple steel balls are filled in the circulation channel and roll along the circulation channel to push the nut to move linearly along the axis of the cylinder bore.

[0010] Preferably, the circulation channel has a continuous spiral structure on the outer surface of the lead screw, and the beginning and end of the circulation channel are connected to form a closed loop circulation channel.

[0011] Preferably, the cylinder bore is provided with an anti-rotation groove, and the anti-rotation block and the anti-rotation groove form a surface contact fit to restrict the circumferential rotation of the nut.

[0012] Preferably, the anti-rotation groove is a U-shaped groove, and the anti-rotation block is in clearance fit with the side wall and bottom surface of the U-shaped groove.

[0013] Preferably, the front end of the nut is manufactured using an integral molding process to form an end cap-less structure.

[0014] Preferably, the ball screw assembly further includes a drive shaft, which is coaxially connected to the screw to transmit rotational torque.

[0015] Compared with the prior art, the advantages of this utility model are:

[0016] (1) The design of the lead screw external circulation channel and the lead screw anti-rotation block avoids the complex structure of the traditional lead screw slotted installation of the reverser, simplifies the manufacturing process, reduces production costs and reduces stress concentration;

[0017] (2) The U-shaped anti-rotation groove on the inner wall of the cylinder bore contacts and fits with the anti-rotation block surface, effectively restricting the circumferential rotation of the screw nut and improving the stability and motion accuracy of the transmission system;

[0018] (3) The front end of the wire mother is integrally formed, eliminating potential weak links. The overall structure is more compact and robust, improving structural strength and reliability. It can operate stably in harsh environments, reducing equipment failure and downtime. Attached Figure Description

[0019] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0020] Figure 1 This is a cross-sectional view of the ball screw assembly described in this utility model;

[0021] Figure 2 This is a schematic diagram of the lead screw of the present invention;

[0022] Figure 3 This is a schematic diagram of the installation of the lead screw and steel ball described in this utility model;

[0023] Figure 4 This is a schematic diagram of the installation structure of the lead screw and lead nut of this utility model;

[0024] Figure 5 This is a schematic diagram of the ball screw structure of the electromechanical brake described in this utility model.

[0025] The components are: 1. Caliper body; 11. Cylinder bore; 2. Ball screw assembly; 21. Screw; 22. Nut; 23. Steel ball; 24. Anti-rotation block; 25. Circulation channel; 26. Anti-rotation groove; 27. Drive shaft. Detailed Implementation

[0026] The present invention will be further described in detail below with reference to specific embodiments:

[0027] like Figure 1 and Figure 5 As shown, an electromechanical brake ball screw structure includes a caliper body 1 and a ball screw assembly 2. The caliper body 1 serves as the support frame for the entire brake and has a cylinder bore 11 inside. This cylinder bore 11 provides installation space for the ball screw assembly 2 and ensures the stability and guidance of the ball screw 21 during operation. The ball screw 21 includes a screw 21, a nut 22, and steel balls 23. The outer surface of the screw 21 is precision-machined to form a circulation channel 25 with a specific trajectory. The nut 22 is tightly fitted onto the outside of the screw 21, and an anti-rotation block 24 is specially installed on the outer surface of the nut 22 to effectively limit the circumferential rotation of the nut 22. The movement allows the lead screw nut 22 to move linearly along the axis of the lead screw 21, avoiding the stress concentration and wear problems caused by the use of pins to prevent rotation in traditional designs. Specifically, multiple steel balls 23 are filled in the circulation channel 25 on the outer surface of the lead screw 21. When the lead screw 21 rotates, the steel balls 23 roll along the circulation channel 25, replacing sliding friction with rolling friction, which greatly reduces the motion resistance and improves the transmission efficiency. At the same time, the cyclic rolling of the steel balls 23 also ensures that the lead screw nut 22 can continuously and smoothly move linearly along the axis of the cylinder bore 11.

[0028] Furthermore, the ball screw assembly 2 also includes a drive shaft 27, which is coaxially connected to the screw 21 to transmit rotational torque. The coaxial connection between the drive shaft 27 and the screw 21 ensures that the rotational torque can be transmitted stably and accurately along the axial direction of the screw 21.

[0029] In practical applications, when the electromechanical brake receives a braking signal, the motor starts working and drives the lead screw 21 to rotate. As the lead screw 21 rotates, the steel balls 23 filled in the circulation channel 25 begin to roll and push the lead screw nut 22 to move linearly along the axis of the cylinder bore 11. Since the outer surface of the lead screw nut 22 is equipped with an anti-rotation block 24, the lead screw nut 22 will not rotate with the lead screw 21, but will completely convert the rotational motion into linear motion. The linear motion of the lead screw nut 22 will then push the brake pads to move towards the brake disc, ultimately clamping the brake pads and applying braking force to the vehicle's wheels to achieve the purpose of deceleration or parking. In this embodiment, the ball screw 21 structure, by adopting the design of the external circulation channel 25 of the screw 21 and the anti-rotation block 24 of the nut 22, avoids the complex structure of the traditional nut 22 slotted to install the reverser, thereby simplifying the manufacturing process and reducing production costs. Furthermore, the anti-rotation block 24 effectively disperses the stress on the nut 22 during movement, avoiding the concentration of local line contact stress, which helps to reduce fatigue damage on the surface of the nut 22, extend the service life of the ball screw 21, and improve the overall reliability of the brake.

[0030] In this embodiment, as Figures 2-3 As shown, the circulation channel 25 is arranged in a continuous spiral structure along the outer surface of the ball screw 21. This spiral structure ensures that the steel ball 23 can maintain a smooth and continuous motion trajectory during rolling. More importantly, the two ends of the circulation channel 25 are interconnected to form a complete closed-loop circulation channel 25. This allows the steel ball 23 to seamlessly enter the next cycle after completing one roll along the spiral channel without the need for additional steering or reversing mechanisms. This not only eliminates the impact and vibration of the steel ball 23 during reversing in the traditional open-loop structure, making the rolling process of the steel ball 23 more continuous and smooth, but also effectively reduces noise and jerking during braking, improves driving comfort, reduces mechanical wear caused by impact, extends the service life of the ball screw 21, and avoids the risk of the steel ball 23 falling off or getting stuck.

[0031] Furthermore, such as Figures 4-5As shown, an anti-rotation groove 26 is provided on the inner wall of the cylinder bore 11. The anti-rotation groove 26 is designed as a U-shaped groove structure. At the same time, the anti-rotation block 24 is embedded in the anti-rotation groove 26, and the two form a surface contact fit. This contact method can effectively restrict the rotation of the nut 22 in the circumferential direction, ensuring that the nut 22 can only perform axial linear motion. Compared with point contact or line contact, the surface contact method can provide a larger area of ​​constraint force, thereby more accurately and reliably restricting the circumferential rotation of the nut 22. This ensures that the nut 22 can only perform linear motion in the predetermined axial direction during transmission, avoiding transmission errors caused by the rotation of the nut 22, and greatly improving the stability and motion accuracy of the entire transmission system. Furthermore, the anti-rotation block 24 adopts a clearance fit with the side wall and bottom surface of the U-shaped groove. On the one hand, it provides convenience for the installation of parts during the assembly process. Due to the existence of a certain clearance, extremely high precision control is not required during assembly, reducing the difficulty and cost of assembly and improving production efficiency. On the other hand, clearance fit can provide a certain buffer space for the thermal expansion and contraction and deformation of parts during operation, avoiding excessive friction and stress concentration caused by tight fit between parts, thereby reducing wear of parts, extending the service life of anti-rotation block 24, anti-rotation groove 26 and nut 22, and reducing equipment maintenance costs.

[0032] Compared to other groove shapes, U-shaped grooves offer superior structural strength and stability. They can withstand greater external forces without deformation or damage, ensuring the long-term effectiveness of their anti-rotation function. Furthermore, U-shaped grooves are a common structural form with broad applicability in mechanical design and manufacturing. They are easy to integrate with other standard parts and allow for flexible modification and optimization to meet diverse design requirements.

[0033] like Figure 5 As shown, in the design and manufacturing of the wire nut 22, its front end is processed using a one-piece molding process. Specifically, through specific molds and molding techniques, the front end of the wire nut 22 is formed in one piece during the manufacturing process, eliminating the need for a separately installed end cap component as in traditional structures. This results in an end cap-less structure, eliminating potential weak points caused by the connection between the end cap and the wire nut 22 body. In traditional wire nut 22 structures with end caps, the end cap is usually fixed to the wire nut 22 body by welding or interference fit. During long-term use, problems such as loosening and wear may occur due to vibration, impact, or repeated loading and unloading operations, posing a risk of rotation. The one-piece molded end cap-less structure eliminates these connection points, making the overall structure of the wire nut 22 more compact and robust, greatly improving its structural strength and reliability. It can operate stably in harsher working environments, reducing equipment failures and downtime caused by structural damage.

[0034] Furthermore, the end cap-less structure helps improve the sealing effect of the nut 22. In nut 22s with end caps, additional sealing measures, such as sealing rings and sealants, are often required at the connection between the end cap and the body to prevent lubricating oil leakage and the ingress of external dust and impurities. However, these sealing measures may fail over time and with changes in operating conditions, leading to a decline in sealing performance. The one-piece molded end cap-less structure fundamentally avoids this sealing problem at the connection, reduces the possibility of lubricating oil leakage, and better prevents external contaminants from entering the interior of the nut 22, thereby extending the service life of the internal parts of the nut 22 and reducing equipment maintenance costs.

[0035] The above embodiments are only for illustrating the technical concept and features of this utility model, and are intended to enable those skilled in the art to understand the content of this utility model and implement it accordingly. They should not be construed as limiting the scope of protection of this utility model. It is obvious to those skilled in the art that this utility model is not limited to the details of the above exemplary embodiments, and that it can be implemented in other specific forms without departing from the spirit or basic characteristics of this utility model. Therefore, the embodiments should be considered exemplary and non-limiting in all respects. The scope of this utility model is defined by the appended claims rather than the foregoing description, and therefore, all changes falling within the meaning and scope of the equivalents of the claims are intended to be included within this utility model.

Claims

1. A ball screw structure for an electromechanical brake, characterized in that, include: Caliper body (1), the caliper body (1) having a cylinder bore (11); The ball screw assembly (2) is installed in the cylinder bore (11). The ball screw (21) includes a screw (21), a nut (22), and steel balls (23). The nut (22) is sleeved on the outside of the screw (21), and an anti-rotation block (24) is installed on its outer surface to restrict the circumferential movement of the nut (22). The outer surface of the screw (21) is provided with a circulation channel (25). The circulation channel (25) is filled with a plurality of steel balls (23) and rolls along the circulation channel (25) to push the nut (22) to move linearly along the axis of the cylinder bore (11).

2. The electromechanical brake ball screw structure of claim 1, wherein: The circulation channel (25) has a continuous spiral structure on the outer surface of the lead screw (21), and the beginning and end of the circulation channel (25) are connected to form a closed loop circulation channel (25).

3. The electromechanical brake ball screw structure of claim 1, wherein: The cylinder bore (11) is provided with an anti-rotation groove (26), and the anti-rotation block (24) and the anti-rotation groove (26) form a surface contact fit to restrict the circumferential rotation of the nut (22).

4. An electromechanical brake ball screw structure according to claim 3, characterized in that: The anti-rotation groove (26) is a U-shaped groove, and the anti-rotation block (24) is in clearance fit with the side wall and bottom surface of the U-shaped groove.

5. The electromechanical brake ball screw structure of claim 1, wherein: The front end of the filament (22) is manufactured by an integral molding process to form a structure without an end cap.

6. An electromechanical brake ball screw structure according to claim 1, wherein: The ball screw assembly (2) also includes a drive shaft (27) which is coaxially connected to the screw (21) to transmit rotational torque.

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