Ball screw for automobile brake system

Abstract

The utility model discloses a ball screw for automobile brake system, including nut, screw rod and rolling body, the nut is sleeved on screw rod and nut realizes the linear motion of nut along the screw rod axis direction when screw rod rotates with the cooperation of rolling body and screw rod, be provided with reverser between the nut and screw rod, the screw rod is by the cooperation axle for with the transmission cooperation of nut and the transmission axle coaxial connection for with outside automobile motor structure linkage cooperation constitutes, the raceway that is set up for the movement of rolling body is set up on cooperation axle, the transmission axle outer peripheral wall is provided with the thrust needle bearing for with outside pincers body cooperation and the alignment structure for with thrust needle bearing cooperation to make thrust needle bearing with outside pincers body cooperation has the alignment function. The utility model solves the problem that traditional automobile ball screw lacks the alignment function.

Description

Technical Field

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

[0002] As automotive chassis evolve towards integration and linearity, the demands for rapid response and precise control in braking systems are increasing. As a core transmission component of the automotive braking system, the ball screw's structural rationality and performance stability directly determine the effectiveness of braking. While existing ball screws in automotive braking systems can convert rotational motion to linear motion through a nut-mounted screw and rolling elements, and can also achieve rolling element circulation with the aid of a reverser, they suffer from significant defects in structural integration and stress adaptability: First, the drive shaft of the screw and the thrust needle bearing that engages with the external clamp are mostly separate designs, requiring individual assembly. This increases the overall system space required and raises the complexity of manufacturing and installation, making it difficult to meet the compact development requirements of braking systems. Second, traditional ball screws lack a self-aligning structure. When there is a coaxiality deviation during installation, the screw is prone to bearing additional off-center loads, leading to accelerated raceway wear and uneven stress on the rolling elements. This not only reduces the accuracy of braking response but also significantly shortens the screw's service life, failing to meet the high reliability and long durability requirements of automotive braking systems. Utility Model Content

[0003] To address the shortcomings of existing technologies, this utility model provides a ball screw for automotive braking systems, which solves the problem of traditional automotive ball screws lacking self-aligning functionality.

[0004] To achieve the above objectives, this utility model provides a ball screw for an automotive braking system, comprising a nut, a screw, and rolling elements. The nut is sleeved on the screw, and the nut engages with the screw through the rolling elements to achieve linear movement of the nut along the screw axis when the screw rotates. A reversing device is provided between the nut and the screw. The screw is coaxially connected by a mating shaft for transmission engagement with the nut and a drive shaft for linkage engagement with an external automotive motor structure. The mating shaft has raceways for the rolling elements to move. The outer peripheral wall of the drive shaft is provided with a thrust needle roller bearing for engagement with an external clamp and a self-aligning structure for engaging with the thrust needle roller bearing to provide self-aligning function when the thrust needle roller bearing engages with the external clamp.

[0005] The advantages of adopting the above technical solution are as follows: the nut and lead screw, through the cooperation of rolling elements, can efficiently convert the rotational motion of the lead screw into the axial linear motion of the nut, ensuring the smoothness of caliper drive during braking and meeting the requirements of the braking system for transmission efficiency; the setting of the reverser can realize the cyclic motion of the rolling elements, preventing the rolling elements from leaving the mating trajectory and maintaining the continuity and stability of transmission; at the same time, the lead screw has a mating shaft and a drive shaft that are coaxially connected. The raceway on the mating shaft provides a stable motion path for the rolling elements, ensuring transmission accuracy, while the drive shaft can stably link the external automotive motor structure and the thrust needle roller bearing, realizing the coordination of power transmission and axial force bearing; the aforementioned thrust needle roller bearing, in cooperation with the external caliper, can effectively withstand the axial force generated during braking, preventing the lead screw from being damaged due to excessive axial force, while the self-aligning structure allows the thrust needle roller bearing to have a self-aligning function when in cooperation with the external caliper, compensating for installation coaxiality deviation, preventing the lead screw from bearing off-center load, extending the overall service life of the lead screw, and solving the problem of the lack of self-aligning function in traditional ball screws.

[0006] The present invention further comprises: the thrust needle roller bearing including an inner washer, an outer washer and a plurality of needle rollers movably disposed between the inner washer and the outer washer; the self-aligning structure including a self-aligning surface circumferentially disposed on the outer wall of the outer washer; the radial section of the self-aligning surface is inclined relative to the outer peripheral wall of the outer washer and the radial section of the self-aligning surface gradually inclines from the outer peripheral wall of the outer washer along the direction from the mating shaft to the transmission shaft toward the inner peripheral wall of the outer washer.

[0007] The advantages of adopting the above technical solution are as follows: the inner and outer washers of the thrust needle roller bearing are combined to form a stable space for the needle rollers, ensuring the positioning accuracy of the needle rollers during movement. The needle rollers can convert axial force into rolling friction, reducing friction loss when the thrust needle roller bearing is subjected to axial force, and improving force transmission efficiency and bearing service life. The self-aligning structure adopts a self-aligning surface circumferentially set on the outer wall of the outer washer, and the radial section of the self-aligning surface is relatively inclined to the outer peripheral wall of the outer washer, gradually inclining towards the inner peripheral wall of the outer washer along the direction from the mating shaft to the transmission shaft. This inclined structure allows the thrust needle roller bearing to adaptively adjust the contact angle through the inclined surface of the self-aligning surface when it is mated with the external clamp, accurately compensating for the coaxiality deviation generated during installation, avoiding the screw bearing off-center load due to poor coaxiality, reducing abnormal wear of the raceway and rolling elements, ensuring the screw transmission accuracy, and improving the adaptability of the thrust needle roller bearing to external components, thus enhancing the stress stability of the overall structure.

[0008] The present invention is further characterized in that the inner washer is integrally machined with the drive shaft.

[0009] The advantages of adopting the above technical solution are: the inner washer and the drive shaft are integrally machined, which eliminates the assembly steps after the inner washer and drive shaft are machined separately, simplifies the manufacturing process of the ball screw, reduces the risk of errors during assembly, and improves production efficiency. Moreover, the integral machining can ensure the coaxiality of the inner washer and the drive shaft, avoiding uneven force on the inner washer due to coaxiality deviation during separate assembly, thereby preventing internal force imbalance of the thrust needle roller bearing, ensuring the stability of the needle roller movement, and improving the uniformity of force transmission. At the same time, the integral structure can enhance the connection strength between the inner washer and the drive shaft, reduce the gap between components, prevent the inner washer from loosening or shifting during long-term use, improve the structural reliability of the thrust needle roller bearing, and thus ensure the overall transmission stability and service life of the screw, reducing later maintenance costs.

[0010] The present invention further comprises: a protrusion formed circumferentially on the outer peripheral wall of the drive shaft; the protrusion being integrally connected with the inner washer; the outer washer being sleeved on the protrusion; the side wall of the protrusion and the outer peripheral wall of the drive shaft forming a stepped surface; the inner peripheral wall of the outer washer being bent toward the stepped surface to form a limiting part; the limiting part being annular; the inner wall of the limiting part being clearance-fitted with the stepped surface; and the inner peripheral wall of the limiting part being clearance-fitted with the outer peripheral wall of the drive shaft.

[0011] The advantages of adopting the above technical solution are as follows: The protrusion formed circumferentially on the outer peripheral wall of the drive shaft is integrally connected with the inner washer, which can further enhance the connection stability between the inner washer and the drive shaft, improve the load-bearing capacity of the inner washer, and prevent the inner washer from deforming or displacing due to force. The outer washer is fitted on the protrusion, which can achieve precise positioning of the outer washer and prevent the outer washer from moving arbitrarily in the axial direction, thus ensuring the stability of the internal structure of the thrust needle roller bearing. At the same time, the stepped surface formed by the combination of the side wall of the protrusion and the outer peripheral wall of the drive shaft can cooperate with the annular limiting part of the bent inner peripheral wall of the outer washer. The clearance fit between the inner wall of the limiting part and the stepped surface and the outer peripheral wall of the drive shaft can not only limit the axial displacement of the outer washer and prevent the outer washer from falling out of the assembly position, but also provide a certain amount of movement space for the outer washer, which is convenient for adjusting the angle of the outer washer during the self-aligning process. It takes into account both the reliability of the limiting and the flexibility of the self-aligning, and prevents the outer washer from failing to achieve the self-aligning function due to excessively tight limiting or structural instability due to excessively loose limiting, thereby improving the synergistic effect between the thrust needle roller bearing and the self-aligning structure.

[0012] The present invention is further provided that: a clamp is detachably connected to the drive shaft, and the inner wall of the clamp is configured to fit with the outer wall of the limiting part with a clearance.

[0013] The advantages of adopting the above technical solution are: the detachable clamp on the drive shaft facilitates the maintenance or replacement of the thrust needle roller bearing in the later stage, and the clamp can be removed without disassembling the entire screw structure, reducing the difficulty of maintenance operations and improving maintenance convenience; the clearance fit between the inner wall of the clamp and the outer wall of the limiting part can form a radial constraint on the limiting part, preventing the limiting part from radially shifting during the force process, thereby avoiding the outer washer shifting and causing misalignment of the internal structure of the thrust needle roller bearing, ensuring the stability of the needle roller movement trajectory, and reducing abnormal wear. Attached Figure Description

[0014] Figure 1 This is a side view of the present invention; Figure 2 This is a cross-sectional view of the present invention. Detailed Implementation

[0015] This utility model provides a ball screw for an automotive braking system, including a nut 1, a lead screw 11, and rolling elements 12. The nut 1 is sleeved on the lead screw 11, and the nut 1 cooperates with the lead screw 11 through the rolling elements 12 to achieve linear movement of the nut 1 along the axis of the lead screw 11 when the lead screw 11 rotates. A reversing device 13 is provided between the nut 1 and the lead screw 11. The lead screw 11 is coaxially connected by a mating shaft 111 for transmission cooperation with the nut 1 and a transmission shaft 112 for linkage cooperation with an external automotive motor structure. The transmission shaft 111 is configured such that a raceway for the rolling element 12 is provided on its mating shaft 111. The outer peripheral wall of the transmission shaft 112 is provided with a thrust needle roller bearing 23 for mating with an external clamp, and a self-aligning structure for mating with the thrust needle roller bearing 23 to provide self-aligning functionality when mating with the external clamp. The thrust needle roller bearing 23 includes an inner washer 21, an outer washer 22, and a plurality of needle rollers 23 movably disposed between the inner washer 21 and the outer washer 22. The self-aligning structure includes circumferential... The self-aligning surface 221 is disposed on the outer wall of the outer washer 22. The radial section of the self-aligning surface 221 is inclined relative to the outer peripheral wall of the outer washer 22, and the radial section of the self-aligning surface 221 gradually inclines towards the inner peripheral wall of the outer washer 22 from the outer peripheral wall of the outer washer 22 along the direction from the mating shaft 111 to the drive shaft 112. The inner washer 21 is integrally machined with the drive shaft 112. A protrusion 113 is formed circumferentially on the outer peripheral wall of the drive shaft 112. The protrusion 113 is integrally connected to the inner washer 21. The outer washer 22... Two sleeves are mounted on the protrusion 113. The side wall of the protrusion 113 and the outer peripheral wall of the drive shaft 112 combine to form a stepped surface. The inner peripheral wall of the outer washer 22 is bent toward the stepped surface to form a limiting part 222. The limiting part 222 is arranged in a ring shape. The inner wall of the limiting part 222 is in clearance fit with the stepped surface and the inner peripheral wall of the limiting part 222 is in clearance fit with the outer peripheral wall of the drive shaft 112. A clamp 24 is detachably connected to the drive shaft 112. The inner wall of the clamp 24 is in clearance fit with the outer wall of the limiting part 222.

[0016] 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 for an automotive braking system, comprising a nut, a lead screw, and rolling elements, wherein the nut is sleeved on the lead screw and engages with the lead screw via the rolling elements to achieve linear movement of the nut along the axis of the lead screw when the lead screw rotates, and a reversing device is provided between the nut and the lead screw, characterized in that: The lead screw is coaxially connected to a mating shaft for engaging with a nut and a transmission shaft for engaging with an external automotive motor structure. The mating shaft has a raceway for the movement of the rolling elements. The outer peripheral wall of the transmission shaft is provided with a thrust needle roller bearing for engaging with an external clamp and a self-aligning structure for engaging with the thrust needle roller bearing so that the thrust needle roller bearing has a self-aligning function when engaging with the external clamp.

2. The ball screw for an automotive braking system according to claim 1, characterized in that: The thrust needle roller bearing includes an inner washer, an outer washer, and a plurality of needle rollers movably disposed between the inner washer and the outer washer. The self-aligning structure includes a self-aligning surface circumferentially disposed on the outer wall of the outer washer. The radial section of the self-aligning surface is inclined relative to the outer peripheral wall of the outer washer, and the radial section of the self-aligning surface gradually inclines from the outer peripheral wall of the outer washer along the direction from the mating shaft to the transmission shaft toward the inner peripheral wall of the outer washer.

3. The ball screw for an automotive braking system according to claim 2, characterized in that: The inner washer is integrally machined with the drive shaft.

4. A ball screw for an automotive braking system according to claim 2, characterized in that: A protrusion is formed circumferentially on the outer peripheral wall of the drive shaft. The protrusion is integrally connected with the inner washer. The outer washer is sleeved on the protrusion. The side wall of the protrusion and the outer peripheral wall of the drive shaft combine to form a stepped surface. The inner peripheral wall of the outer washer is bent toward the stepped surface to form a limiting part. The limiting part is arranged in a ring shape. The inner wall of the limiting part is in clearance fit with the stepped surface, and the inner peripheral wall of the limiting part is in clearance fit with the outer peripheral wall of the drive shaft.

5. A ball screw for an automotive braking system according to claim 4, characterized in that: A clamp is detachably connected to the drive shaft, and the inner wall of the clamp is fitted with the outer wall of the limiting part with a clearance.

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