Ball screw mechanism of automobile braking system

Abstract

The utility model discloses a ball screw mechanism of an automobile braking system, which comprises a nut, a screw rod, a steel ball and a reverser, the screw rod is provided with an internal spline matched with an external spline on an output shaft of an external speed reducer, and the nut is provided with a through hole for installing the reverser. The nut is designed to be of a semi-closed integrated structure, the tail end of the nut is provided with a movable opening allowing the lead screw to be placed in and move, the outer circumferential wall of the lead screw is provided with a rolling way in a variable pitch circle spiral shape, and the lead screw is matched with the reverser to achieve circulating rolling of the steel balls in the rolling way. The lead screw is provided with an aligning structure used for adjusting the eccentric angle of the lead screw when the coaxiality of an external braking system is poor, and the tail end of the lead screw is provided with a stopping structure used for preventing the nut and the lead screw from being clamped when the nut retreats. The automobile brake system solves the problems that a traditional automobile brake system is low in efficiency and large in occupied space, unbalance loading is prone to occurring when the coaxiality is poor, and the nut and the lead screw are prone to being clamped when the nut retreats.

Description

Technical Field

[0001] This utility model relates to the field of automotive ball screw technology, specifically a ball screw mechanism for an automotive braking system. Background Technology

[0002] Currently, ball screw mechanisms in automotive braking systems face numerous technical challenges in practical applications. Traditional ball screw mechanisms suffer from low transmission efficiency and insufficiently smooth ball circulation, making it difficult to meet the demands of rapid braking response and affecting the timeliness and effectiveness of vehicle braking. Furthermore, their structural design is not optimized; for example, the lack of a compact stop structure results in a large overall axial length, occupying more space and hindering compact interior layout and space utilization. Additionally, when the braking system's coaxiality is poor, existing mechanisms lack self-aligning structures, making the screw susceptible to excessive off-center loads, leading to accelerated wear or even damage, reducing mechanism stability and service life. During nut retraction, conventional structures, lacking a smooth transition design, are prone to nut and screw jamming, further impacting mechanism reliability and long-term operational performance. Utility Model Content

[0003] To address the shortcomings of existing technologies, this utility model provides a ball screw mechanism for an automotive braking system, which solves the problems of low efficiency, large space occupation, susceptibility to uneven loads when coaxiality is poor, and easy jamming of the screw when the nut retracts in traditional automotive braking systems.

[0004] To achieve the above objectives, this utility model provides a ball screw mechanism for an automotive braking system, including a nut, a lead screw, steel balls, and a reverser. The lead screw has an internal spline for engaging with an external spline on the output shaft of an external reducer. The nut has a through hole for mounting the reverser. The nut has a semi-enclosed integrated structure design, and its end has an opening for the lead screw to be inserted and moved. The outer peripheral wall of the lead screw has a raceway in the shape of a variable circular helix. The lead screw and the reverser cooperate to realize the cyclic rolling of the steel balls in the raceway. The lead screw is provided with a self-aligning structure for adjusting the eccentricity angle of the lead screw when the coaxiality of the external braking system is poor. The end of the lead screw is provided with a stop structure to prevent the nut from jamming with the lead screw when the nut retracts.

[0005] The advantages of adopting the above technical solution are as follows: The technology utilizes the internal spline of the lead screw and the external spline of the reducer output shaft to achieve efficient power transmission and ensure precise braking action. The semi-enclosed integrated structure design of the nut effectively isolates the lead screw from the external environment, preventing the intrusion of dust, moisture, and other impurities, thus improving the mechanism's sealing and durability. Simultaneously, the variable-helical raceway on the outer circumference of the lead screw, in conjunction with the reverser, ensures smoother circulation of the steel balls, greatly improving transmission efficiency and accelerating braking response. Furthermore, the self-aligning structure in this technology can adjust the eccentricity angle of the lead screw when the coaxiality of the external braking system is poor, preventing the mechanism from bearing excessive eccentric loads. This enhances operational stability; the end stop structure of the lead screw prevents the nut from jamming during retraction, ensuring long-term reliable operation of the mechanism; in addition, the overall structure is compact, effectively saving space and solving the problems of low efficiency, large space occupation, and insufficient reliability of existing braking systems. It also has the advantages of high strength, stable functionality, and high integration, significantly improving the overall performance of the automotive braking system; in the above technology, the variable pitch circle helix refers to a helical structure in which the pitch (screw pitch) or radius of the helix changes according to a specific law, which is different from the conventional helix with equal pitch (or equal radius). It is a traditionally processed structure, so its structure and function will not be described in detail.

[0006] The present invention further comprises: the radial cross section of the outer peripheral wall of the lead screw starting end is arc-shaped and forms a first arc-shaped surface; the self-aligning structure includes a self-aligning ring sleeved on the starting end of the lead screw; the inner peripheral wall surface and the inner side wall surface of the self-aligning ring are connected by a smooth arc surface and form a second arc-shaped surface for fitting with the first arc-shaped surface; the outer wall surface of the self-aligning ring is planar and forms a linkage surface for cooperating with an external thrust needle roller bearing.

[0007] The advantages of adopting the above technical solution are as follows: In the above technology, the radial cross section of the outer peripheral wall of the lead screw at the beginning is arc-shaped to form a first arc-shaped surface, which, together with the second arc-shaped surface of the self-aligning ring, forms a self-aligning structure. When the coaxiality of the external braking system is not good, the self-aligning ring can adjust the eccentric angle of the lead screw through the adaptation of the arc-shaped surface, effectively avoiding the mechanism from bearing uneven loads and improving operational stability. The linkage surface of the outer wall of the self-aligning ring cooperates with the external thrust needle roller bearing, which can evenly transmit axial force and enhance the overall load-bearing capacity of the mechanism. The above technology not only makes the self-aligning process more flexible and precise, but also reduces friction loss through the smooth contact between the arc-shaped surfaces, extending the service life of the mechanism. At the same time, the setting of the self-aligning ring further optimizes the force transmission path, ensuring that the lead screw can still maintain stable operation under complex working conditions, improving the reliability and adaptability of the braking system, and providing a strong guarantee for the precise control of automobile braking.

[0008] The present invention further comprises: the end face of the lead screw and the outer peripheral wall of the lead screw end are connected by a smooth arc surface to form a third arc surface, and the third arc surface is the stop structure.

[0009] The advantages of adopting the above technical solution are as follows: In this technology, the smooth arc surface connection between the end face of the lead screw and the outer peripheral wall forms a third arc surface as a stop structure, replacing the conventional stop mechanism. This effectively reduces the overall axial length of the ball screw, making the structure more compact and saving installation space. Simultaneously, the arc surface design prevents rigid jamming between the nut and the end of the lead screw during retraction, ensuring smooth linear movement of the nut. During braking, the nut's retraction is guided by the arc surface, resulting in a smoother movement trajectory, reducing the risk of mechanical interference and improving the stability of the mechanism. Furthermore, the smooth transition characteristics of the arc surface can reduce stress concentration, enhance the structural strength of the lead screw end, and extend its service life.

[0010] The present invention is further provided with a trunnion on the reverser for cooperating with the raceway.

[0011] The advantages of adopting the above technical solution are: the trunnion on the reverser that cooperates with the raceway can accurately guide the steel ball to circulate in the raceway. The cooperation between the trunnion and the raceway ensures the stability of the steel ball's trajectory, reduces collision and friction loss between the steel balls, and improves transmission efficiency. During braking, the smoothness of the steel ball circulation directly affects the efficiency of the lead screw rotation driving the nut's linear motion. The trunnion makes the steel ball circulation more orderly, thereby improving the braking response speed.

[0012] The present invention further includes a smooth curved surface connection between the inner peripheral wall of the through hole and the raceway, forming a transition chamfer for smooth transition between the reverser and the lead screw.

[0013] The advantages of adopting the above technical solution are: the chamfer between the inner wall of the through hole and the raceway in the above technology enables a smooth transition between the reverser and the lead screw, avoiding obstruction of the steel ball when passing through the connection between the reverser and the raceway, ensuring smooth and uninterrupted rolling of the steel ball, effectively improving transmission efficiency, and the smooth transition of the chamfer reduces the impact between the steel ball and the mechanism, reduces wear, and extends the service life of the steel ball, reverser and lead screw.

[0014] The present invention further includes: a sealing groove for cooperating with an external sealing gasket or sealing tool is provided on the outer peripheral wall of the beginning end of the nut, and an anti-rotation groove for cooperating with an external tool through a pin or other locking structure is provided on the outer peripheral wall of the end of the nut.

[0015] The advantages of adopting the above technical solution are: the sealing groove on the outer peripheral wall of the nut at the beginning of the above technology can cooperate with external sealing gaskets or sealing fixtures, which can significantly improve the sealing performance of the mechanism, effectively isolate external impurities, prevent dust and moisture from entering, protect internal components such as lead screws and steel balls, and extend the service life of the mechanism. The anti-rotation groove on the outer peripheral wall of the nut at the end of the nut can cooperate with external fixtures through pins or other locking structures, which can strictly limit the rotation of the nut, ensure that the nut only makes linear motion during the movement, and improve the accuracy of the braking action. Attached Figure Description

[0016] Figure 1 This is a three-dimensional view of the present invention;

[0017] Figure 2 This is a front sectional view of the present invention;

[0018] Figure 3 This is a side view of the lead screw in this utility model;

[0019] Figure 4 This is a schematic diagram showing the position of the trunnion of the reversing device in this utility model;

[0020] Figure 5 This is a side sectional view of the centering ring in this utility model. Detailed Implementation

[0021] This utility model provides a ball screw mechanism for an automotive braking system, including a nut 1, a lead screw 2, steel balls 11, and a reverser 3. The lead screw 2 has an internal spline for engaging with an external spline on the output shaft of an external reducer. The nut 1 has a through hole 12 for mounting the reverser 3. The nut 1 has a semi-enclosed integrated structure design, and its end has an opening 13 for inserting and moving the lead screw 2. The outer peripheral wall of the lead screw 2 has a raceway 23 in the shape of a variable circular helix. The lead screw 2 cooperates with the reverser 3 to realize the cyclic rolling of the steel balls 11 in the raceway. The lead screw 2 is provided with a self-aligning structure for adjusting the eccentricity angle of the lead screw 2 when the coaxiality of the external braking system is poor. The end of the lead screw 2 is provided with a stop structure to prevent the nut 1 from jamming with the lead screw 2 when the nut 1 retracts. The radial cross section of the outer peripheral wall at the beginning of the lead screw 2 is arc-shaped and forms a first arc-shaped surface 21. The self-aligning structure includes a sleeve on the lead screw. The self-aligning ring 4 at the beginning of the 2 has a smooth arc connecting its inner peripheral wall and inner side wall, forming a second arc surface 41 for fitting with the first arc surface 21. The outer side wall of the self-aligning ring 4 is planar and has a linkage surface 42 for cooperating with an external thrust needle roller bearing. The end face of the lead screw 2 is smoothly connected to the outer peripheral wall of the end of the lead screw 2, forming a third arc surface 22. The third arc surface 22 is the stop structure. The reverser 3 is provided with a trunnion 31 for cooperating with the raceway. The inner peripheral wall of the through hole 12 is smoothly connected to the raceway, forming a transition chamfer 121 for smooth transition between the reverser 3 and the lead screw 2. The outer peripheral wall of the beginning of the nut 1 is circumferentially provided with a sealing groove 14 for cooperating with an external sealing gasket or sealing tool. The outer peripheral wall of the end of the nut 1 is provided with an anti-rotation groove 15 for cooperating with an external tool through a pin or other locking structure.

[0022] The foregoing has shown and described the basic principles and main features of this utility model, as well as its advantages. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of this utility model. Various changes and modifications may be made to this utility model without departing from its spirit and scope. All such changes and modifications fall within the scope of protection of this utility model as defined by the appended claims and their equivalents.

Claims

1. A ball screw mechanism for an automotive braking system, comprising a nut, a lead screw, steel balls, and a reverser, wherein the lead screw is provided with an internal spline for engaging with an external spline on the output shaft of an external reducer, and the nut is provided with a through hole for mounting the reverser, characterized in that: The nut has a semi-enclosed integrated structure design and an opening at its end for inserting and moving the lead screw. The lead screw has a variable circular spiral raceway on its outer peripheral wall. The lead screw cooperates with the reverser to realize the cyclic rolling of the steel ball in the raceway. The lead screw is equipped with a self-aligning structure for adjusting the eccentricity angle of the lead screw when the coaxiality of the external braking system is not good. The end of the lead screw is equipped with a stop structure to prevent the nut from jamming with the lead screw when the nut retracts.

2. The ball screw mechanism of an automotive braking system according to claim 1, characterized in that: The radial cross section of the outer peripheral wall at the beginning of the lead screw is arc-shaped and forms a first arc-shaped surface. The self-aligning structure includes a self-aligning ring sleeved on the beginning of the lead screw. The inner peripheral wall surface and the inner side wall surface of the self-aligning ring are connected by a smooth arc surface and form a second arc-shaped surface for fitting with the first arc-shaped surface. The outer side wall surface of the self-aligning ring is planar and forms a linkage surface for cooperating with an external thrust needle roller bearing.

3. The ball screw mechanism of an automotive braking system according to claim 1, characterized in that: The end face of the lead screw and the outer peripheral wall of the lead screw are connected by a smooth arc surface to form a third arc surface, which is the stop structure.

4. The ball screw mechanism of an automotive braking system according to claim 1, characterized in that: The reverser is provided with a trunnion for engaging with the raceway.

5. The ball screw mechanism of an automotive braking system according to claim 1, characterized in that: The inner peripheral wall of the through hole and the raceway are connected by a smooth curved surface, forming a transition chamfer to allow the reverser and the lead screw to transition smoothly.

6. The ball screw mechanism of an automotive braking system according to claim 1, characterized in that: The nut has a circumferential sealing groove on its starting end outer peripheral wall for engaging with an external sealing gasket or sealing fixture, and an anti-rotation groove on its ending end outer peripheral wall for engaging with an external fixture via a pin or other locking structure.

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