Ball screw pair and brake having the same

Abstract

The utility model relates to electronic mechanical brake technology field, concretely relates to a ball screw pair and the brake with the ball screw pair, a ball screw pair, including ball screw assembly, the ball screw assembly includes nut, screw and is located between the ball, the nut is the cup -shaped structure of one -end opening, the other end is closed, and the inner bottom of its closed end is provided with first stop boss, the ball screw assembly still includes drive shaft and stop ring, the drive shaft penetrates the screw, and fixedly connected between both, the stop ring fixedly sets up in one end of drive shaft, and with first stop boss position corresponds. Therefore, provide a ball screw pair and the brake with the ball screw pair, to solve the ball screw pair in prior art in the ball screw pair because of no limit or unreasonable limit structure and lead to the early failure problem of ball screw pair.

Description

Technical Field

[0001] This utility model relates to the field of electromechanical brake technology, and in particular to a ball screw pair and a brake having the ball screw pair. Background Technology

[0002] A brake, commonly known as a brake, is a device that slows down, stops, or keeps a moving part at a stop. Electromechanical brakes, in particular, use a motor to drive a ball screw assembly, converting rotational motion into linear motion, which in turn pushes the brake pads to clamp the brake disc, thus achieving vehicle braking. The ball screw assembly, as a core transmission component, directly affects the braking safety of the entire vehicle. However, due to the extremely compact internal space of electromechanical brakes, the traditional approach of incorporating a limiting structure between the nut and the screw is extremely difficult to implement. Therefore, many designs in the industry have had to abandon the integration of mechanical limiting structures within the ball screw assembly.

[0003] To address this issue, Chinese invention patent CN117662651A discloses a brake caliper that uses a limiting rib on the nut and a limiting boss on the lead screw that cooperates with the limiting rib for limiting, thereby preventing the nut from excessively retracting. However, after in-depth research, the inventors discovered certain limitations to this solution: machining the limiting boss within a compact space weakens the structural strength of the lead screw body, and damage to the boss on the lead screw renders the entire lead screw unusable, resulting in poor economic efficiency.

[0004] Therefore, it is urgent to design a ball screw pair and a brake with such a ball screw pair to solve the problem of early failure of existing ball screw pairs caused by the lack of limit or unreasonable limit structure. Utility Model Content

[0005] The purpose of this invention is to provide a ball screw assembly and a brake having the ball screw assembly, so as to solve the problem of early failure of ball screw assemblies caused by the lack of limit or unreasonable limit structure in the prior art.

[0006] The technical solution of this utility model is: a ball screw pair, including a ball screw assembly, the ball screw assembly including a nut, a screw and balls disposed between the two, the nut is a cup-shaped structure with one end open and the other end closed, and a first stop boss is provided on the inner bottom of the closed end. The ball screw assembly also includes a drive shaft and a stop ring; The drive shaft passes through the lead screw, and the two are fixedly connected; The stop ring is fixedly disposed at one end of the drive shaft and corresponds to the position of the first stop boss. When the nut retracts to the zero position, the stop ring and the first stop boss cooperate to form a limiting structure.

[0007] Preferably, the stop ring is provided with a second stop boss. When the nut retracts to the zero position, the second stop boss abuts against the first stop boss, thereby restricting the nut from continuing to move axially.

[0008] Preferably, the end of the drive shaft is provided with a press-fitting station, and the stop ring is provided with a mounting hole. The mounting hole is adapted to the press-fitting station, and the stop ring is sleeved on the press-fitting station through the mounting hole and fixed, thereby fixing the stop ring on the drive shaft.

[0009] Preferably, the pressing station is constructed as a smooth rod structure or a knurled rod structure.

[0010] Preferably, the mounting hole is a smooth hole or a knurled hole, and the smooth hole or knurled hole of the mounting hole corresponds to the smooth rod structure or the knurled rod structure, respectively.

[0011] Preferably, the outer circumferential surface of the lead screw is provided with a helical raceway, which is used to accommodate the ball bearings. The helical raceway, the inner wall of the nut, and the ball bearings disposed between them together constitute the force transmission path.

[0012] Preferably, ball return devices are provided at both ends of the spiral raceway to circulate the balls.

[0013] A brake includes the aforementioned ball screw assembly and a brake caliper body. The ball screw assembly is housed within a cylinder bore of the brake caliper body, and an anti-rotation structure is provided between the outer peripheral wall of the nut and the inner peripheral wall of the cylinder bore to prevent the nut from rotating relative to the brake caliper body while allowing the nut to move axially relative to the brake caliper body.

[0014] Compared with the prior art, the advantages of this utility model are: (1) By setting an independent stop ring at the end of the drive shaft and cooperating with the first stop boss at the bottom of the nut, a rigid hard stop point is formed. When the nut retracts to the zero position, the impact force is directly borne by the stop ring and the drive shaft. The force flow completely avoids the balls and raceways, eliminating the problems of deformation, peeling and transmission pair jamming caused by abnormal extrusion of the balls, and significantly improving the reliability and safety of the braking system.

[0015] (2) The stop ring is independently replaceable and is fixed to the drive shaft by press-fitting or welding. This modular design concentrates the vulnerable parts on the stop ring. When the limiting structure wears due to long-term impact, maintenance personnel can quickly replace the stop ring without disassembling the lead screw assembly, significantly shortening maintenance time. Compared with the limiting structure integrated with the lead screw, this avoids the problem of the entire lead screw being scrapped due to local damage, effectively extending the service life of the assembly. Attached Figure Description

[0016] The present invention will be further described below with reference to the accompanying drawings and embodiments: Figure 1 This is a schematic diagram of the overall structure of the ball screw assembly described in this utility model; Figure 2 This is a cross-sectional view of the overall structure of the ball screw assembly described in this utility model; Figure 3 This is a schematic diagram of the drive shaft structure described in this utility model; Figure 4 This is a schematic diagram of the stop ring structure described in this utility model; Figure 5 This is a schematic diagram of the external structure of the lead screw described in this utility model; Figure 6 This is a cross-sectional view of the brake structure described in this utility model; The components are: 1. Ball screw assembly; 11. Nut; 111. First stop boss; 12. Screw; 121. Helical raceway; 13. Drive shaft; 131. Press-fitting station; 14. Stop ring; 141. Second stop boss; 142. Mounting hole; 15. Ball; 151. Ball returner; 2. Brake caliper body. Detailed Implementation

[0017] The present invention will be further described in detail below with reference to specific embodiments: like Figures 1 to 6 As shown, a brake includes a ball screw pair and a brake caliper body 2. The ball screw pair includes a ball screw assembly 1, which includes a nut 11, a screw 12, and balls 15 disposed between the two, as well as a drive shaft 13 and a stop ring 14.

[0018] like Figure 2 As shown, the nut 11 is a cup-shaped structure with one end open and the other end closed, and a first stop boss 111 is provided on the inner bottom of its closed end.

[0019] The drive shaft 13 passes through the lead screw 12 and the two are fixedly connected. The stop ring 14 is fixedly disposed at one end of the drive shaft 13 and corresponds to the position of the first stop boss 111.

[0020] The stop ring 14 is provided with a second stop boss 141. When the nut 11 retracts to the zero position, the second stop boss 141 abuts against the first stop boss 111, thereby restricting the nut 11 from continuing to move axially.

[0021] The end of the drive shaft 13 is provided with a press-fit station 131, and the stop ring 14 is provided with a mounting hole 142. The mounting hole 142 is adapted to the press-fit station 131. The stop ring 14 is sleeved on the press-fit station 131 through the mounting hole 142 and fixed, thereby fixing the stop ring 14 on the drive shaft 13.

[0022] When the drive shaft 13 rotates, it drives the lead screw 12 and the stop ring 14 to rotate together. Under the constraint of the anti-rotation structure, the nut 11 converts the rotational motion of the lead screw 12 into the axial linear motion of the nut 11 relative to the brake caliper body 2. When the nut 11 returns to the zero position (i.e., the initial position when the brake is released), the second stop boss 141 cooperates with the first stop boss 111 to form a limiting structure.

[0023] The press-fitting station 131 is constructed as a smooth rod structure or a knurled rod structure. The mounting hole 142 is a smooth hole or a knurled hole, and the smooth hole or the knurled hole of the mounting hole 142 corresponds to the smooth rod structure or the knurled rod structure, respectively.

[0024] like Figure 5 As shown, a spiral raceway 121 is provided on the outer peripheral surface of the lead screw 12. The spiral raceway 121 is used to accommodate the ball 15. The spiral raceway 121, the inner wall of the nut 11, and the ball 15 disposed between the two together constitute the force transmission path.

[0025] The spiral raceway 121 is equipped with ball return devices 151 at both ends to circulate the balls 15. When the balls 15 roll to the end of the raceway, the ball return devices 151 guide them into their own return channels and guide them to the beginning of the raceway to re-enter the load area, thereby forming a continuous cyclic motion.

[0026] like Figure 6 As shown, the ball screw assembly 1 is housed within the cylinder bore of the brake caliper body 2, and an anti-rotation structure is provided between the outer peripheral wall of the nut 11 and the inner peripheral wall of the cylinder bore to prevent the nut 11 from rotating relative to the brake caliper body 2, while allowing the nut 11 to move axially relative to the brake caliper body 2. This structural design draws on the mature solution of traditional brake caliper pistons, achieving reliable anti-rotation while ensuring the overall braking performance of the brake.

[0027] Working principle: During the braking and clamping process, when the brake is engaged, the torque of the drive power source (usually a motor) is input to the drive shaft 13 through the coupling. The drive shaft 13 then drives the lead screw 12, which is fixed to it, to rotate synchronously. At this time, the nut 11 is constrained by its external anti-rotation structure and cannot rotate with the lead screw, thus converting the rotational motion of the lead screw into the axial linear motion of the nut 11 itself, causing the nut 11 to move forward and push the brake pads to perform clamping. During this process, the balls 15 roll smoothly in the helical raceway and continuously operate through the circulation loop constructed by the ball returner 151, transmitting a huge axial clamping force in a highly efficient and low-friction manner.

[0028] During the limit braking process, when replacing the brake pads or resetting the system, the lead screw 12 rotates in the opposite direction under the drive of the drive shaft 13, causing the nut 11 to retract backward. When the nut 11 retracts to the zero position, its bottom first stop boss 111 abuts against the second stop boss 141 on the stop ring 14 fastened to the end of the drive shaft, forming a rigid mechanical stop structure, thereby restricting the nut 11 from continuing to retract. At this time, the torque transmitted from the motor is directly converted into shear force and bending moment acting on the stop ring 14 and the drive shaft 13, and cannot continue to be converted into axial force to push the nut 11. This force flow path bypasses the ball bearing 15, fundamentally avoiding the problem in the prior art where the ball bearing 15 is subjected to abnormal compression due to the lack of limit, leading to deformation, peeling, or even jamming.

[0029] 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 assembly, comprising a ball screw assembly (1), the ball screw assembly (1) comprising a nut (11), a screw (12), and balls (15) disposed between the two, characterized in that: The nut (11) is a cup-shaped structure with one end open and the other end closed, and a first stop boss (111) is provided at the inner bottom of the closed end. The ball screw assembly (1) also includes a drive shaft (13) and a stop ring (14). The drive shaft (13) passes through the lead screw (12) and the two are fixedly connected; The stop ring (14) is fixedly disposed at one end of the drive shaft (13) and corresponds to the position of the first stop boss (111); When the nut (11) retracts to the zero position, the stop ring (14) cooperates with the first stop boss (111) to form a limiting structure.

2. A ball screw pair according to claim 1, characterized in that: The stop ring (14) is provided with a second stop boss (141). When the nut (11) retracts to the zero position, the second stop boss (141) abuts against the first stop boss (111), thereby restricting the nut (11) from continuing to move axially.

3. A ball screw pair according to claim 1 or 2, characterized in that: The end of the drive shaft (13) is provided with a press-fit station (131), and the stop ring (14) is provided with a mounting hole (142). The mounting hole (142) and the press-fit station (131) are adapted to each other. The stop ring (142) is sleeved on the press-fit station (131) through the mounting hole (142) and fixed, thereby fixing the stop ring (14) on the drive shaft (13).

4. A ball screw assembly according to claim 3, characterized in that: The pressing station (131) is constructed as a smooth rod structure or a knurled rod structure.

5. A ball screw pair according to claim 4, characterized in that: The mounting hole (142) is a smooth hole or a knurled hole, and the smooth hole or the knurled hole of the mounting hole (142) corresponds to the smooth rod structure or the knurled rod structure respectively.

6. A ball screw assembly according to claim 1, characterized in that: The outer circumferential surface of the lead screw (12) is provided with a spiral raceway (121), which is used to accommodate the ball (15). The spiral raceway (121), the inner wall of the nut (11), and the ball (15) disposed between them together constitute the force transmission path.

7. A ball screw pair according to claim 6, characterized in that: The spiral raceway (121) is provided with ball returners (151) at both ends to circulate the balls (15).

8. A brake, comprising a ball screw assembly as described in any one of claims 1 to 7, and further comprising a brake caliper body (2), characterized in that: The ball screw assembly (1) is housed in the cylinder bore of the brake caliper body (2), and an anti-rotation structure is provided between the outer peripheral wall of the nut (11) and the inner peripheral wall of the cylinder bore to prevent the nut (11) from rotating relative to the brake caliper body (2), while allowing the nut (11) to move axially relative to the brake caliper body (2).

Images