Ball screw protection structure applied to electronic mechanical brake

Abstract

The utility model relates to the technical field of braking systems, in particular to a ball screw protection structure applied to an electronic mechanical brake. A ball screw protection structure applied to an electronic mechanical brake is characterized in that the front end of a threaded section of a ball screw is integrally connected with a screw body, the tail end of the threaded section of the ball screw is connected with a stop structure, the outer side of the ball screw is sleeved with a ball nut, and the front end of the ball nut is connected with an end cover; the outer side of the ball nut is sleeved with a caliper shell. A plurality of guide bosses or guide grooves are connected to the outer side of the ball nut, and the ball nut and the guide bosses are of an integrated structure. A plurality of closed circulation loops are arranged on the outer edge of the threaded section of the ball screw; and a plurality of steel balls are arranged in the circulation loop. Compared with the prior art, when the friction plate is replaced, the steel ball of the ball screw of the dry brake cannot be separated, and damage such as brake force loss or brake force clamping stagnation caused by ball separation is avoided.

Description

Technical Field

[0001] The utility model relates to the technical field of brake systems, in particular to a ball screw protection structure applied to an electronic mechanical brake. Background Art

[0002] As the development trend of future automobile braking, dry braking can be used with higher levels of autonomous driving. However, due to the loss of the backup of the driver's pedal brake, higher safety requirements are placed on the system. With the increase of driving mileage, the brake friction pads will inevitably wear out. When they are worn to a certain extent, they need to be replaced. When replacing the friction pads, the BSD needs to be retracted to a certain position. If it is not retracted in place, the friction pads are not easy to replace. If it is retracted too much, the balls in the ball screw will fall off. As an important component of the BSD, it is particularly important to prevent the balls from falling off the raceway. Summary of the invention

[0003] In order to overcome the deficiencies in the prior art, the utility model provides a ball screw protection structure applied to an electronic mechanical brake, which can ensure that the steel ball of the dry brake ball screw will not fall off when the friction plate is replaced, thereby avoiding the loss of braking force or braking force jamming caused by ball falling off, thereby improving reliability and ensuring safety.

[0004] To achieve the above-mentioned purpose, a ball screw protection structure for an electronic mechanical brake is designed, comprising a ball screw, a ball nut, and a caliper housing. The ball screw is formed integrally of a screw rod body and a screw threaded section, and is characterized in that: the front end of the ball screw threaded section is integrally connected to the screw rod body, the end of the ball screw threaded section is connected to a stop structure, the outer side of the ball screw is sleeved with a ball nut, the front end of the ball nut is connected to an end cover, and the outer side of the ball nut is sleeved with a caliper housing; a plurality of guide bosses or guide grooves are connected to the outer side of the ball nut, and the ball nut and the guide boss are an integrated structure; a plurality of closed circulation loops are provided on the outer edge of the ball screw threaded section; a plurality of steel balls are provided in the circulation loop; the stop structure is an axial stop structure or a circumferential stop structure.

[0005] The axial stop structure is an arc-shaped protruding structure, and the axial stop structure is located at the center of the end of the ball screw thread segment.

[0006] The connection method between the axial stop structure and the end of the ball screw threaded section is one of threaded connection, riveted connection, interference fit connection, welding connection, and integrated connection.

[0007] The circumferential stop structure is a truncated cone-shaped protruding structure, and the circumferential stop structure is located on the inner side of the end cover; the circumferential stop structure is arranged in coordination with the anti-rotation structure.

[0008] The anti-rotation structure is connected to the end of the threaded section of the ball screw, and the connection mode between the anti-rotation structure and the threaded section of the ball screw is one of threaded connection, riveted connection, interference fit connection, welded connection, and integral connection.

[0009] The circumferential stop structure and the anti-rotation structure are arranged in a double-convex type or a one-convex-one-concave type.

[0010] The connection mode between the circumferential stop structure and the end cover is one of threaded connection, riveted connection, interference fit connection, welded connection, and integral connection.

[0011] The connection mode between the end cover and the front end of the ball nut is one of interference fit connection, threaded connection, welded connection, and integral connection.

[0012] The connection mode between the guiding boss and the ball nut is one of integral connection, threaded connection, riveted connection, welded connection, and interference fit connection.

[0013] Compared with the prior art, the present utility model provides a ball screw protection structure applied to an electro-mechanical brake, which can ensure that the steel balls of the dry brake ball screw will not come off while replacing the friction plate, avoiding hazards such as loss of braking force or braking force jamming caused by ball detachment, improving reliability, and ensuring safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic structural diagram of the first solution of the present utility model.

[0015] Figure 2 It is a schematic structural diagram of the second solution of the present utility model.

[0016] See Figure 1 , Figure 2 , 1 is the ball screw, 2 is the ball nut, 3 is the end cover, 4 is the caliper housing, 5 is the guiding groove, 6 is the guiding boss, 7 is the axial stop structure, 8 is the anti-rotation structure, and 9 is the circumferential stop structure. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0017] The following further describes the present utility model with reference to the drawings.

[0018] As Figure 1 shown, it is a schematic structural diagram of the first solution of the present utility model.

[0019] The front end of the threaded section of the ball screw 1 is integrally connected to the screw rod body. The end of the threaded section of the ball screw 1 is connected to a stop structure. A ball nut 2 is sleeved outside the ball screw 1. The front end of the ball nut 2 is connected to an end cover 3. A caliper housing 4 is sleeved outside the ball nut 2. A number of guiding bosses 6 or guiding grooves 5 are connected to the outside of the ball nut 2, and the ball nut 2 and the guiding bosses 6 are of an integral structure. The outer edge of the threaded section of the ball screw 1 is provided with a number of closed circulation circuits. A number of steel balls are arranged in the circulation circuits. The said stop structure is an axial stop structure 7 or a circumferential stop structure 9.

[0020] The axial stop structure 7 is an arc-shaped convex structure, and the axial stop structure 7 is located at the central position of the end of the threaded section of the ball screw 1.

[0021] The connection mode between the axial stop structure 7 and the end of the threaded section of the ball screw 1 is one of threaded connection, riveted connection, interference fit connection, welded connection, and integral connection.

[0022] The connection mode between the end cover 3 and the front end of the ball nut 2 is one of interference fit connection, threaded connection, welded connection, and integral connection.

[0023] The connection mode between the guiding bosses 6 and the ball nut 2 is one of integral connection, threaded connection, riveted connection, welded connection, and interference fit connection.

[0024] There is an end cover 3 at the front end of the ball nut 2. The end cover 3 is connected to the ball nut 2 in an interference or threaded or welded manner, or the end cover 3 is integrated with the ball nut 2. An axial stop structure 7 is provided on the front end face of the ball screw 1. The axial stop structure 7 is connected to the ball screw 1 by means of thread or riveting or interference or welding, or the axial stop structure 7 is integrated with the ball screw 1. After the ball nut 2 retracts to a certain position, the top of the axial stop structure 7 contacts the end cover 3, and the ball nut 2 completes the return position. The end cover 3 can not only bear several kilonewtons of axial force from the ball screw 1, but also seal the ball nut 2. A number of guiding bosses 6 or guiding grooves 5 are designed on the outer surface of the ball nut 2. The guiding bosses 6 or guiding grooves 5 and the ball nut 2 are of an integral structure or the guiding bosses 6 and the ball nut 2 are connected in a threaded or riveted or welded or interference manner. The guiding part of the caliper housing 4 and the ball nut 2 is a convex-concave combination. When the caliper receives the instruction to enter the maintenance mode, it controls the speed of the motor and limits its maximum and minimum torques. And the angular deceleration of the motor is fitted by least squares. When the ball nut 2 retracts until the end cover 3 contacts the stop structure 7, which is commonly known as hitting the bottom, the angular deceleration of the motor will increase, and the actual torque of the motor will also increase, and the value of the force sensor will increase. When the above conditions are met at the same time, it can be considered that the ball nut 2 has retracted to the bottommost end.

[0025] As shown Figure 2 in the figure, it is a schematic structural diagram of the second solution of the utility model.

[0026] The front end of the threaded section of the ball screw 1 is integrally connected to the screw rod body. The end of the threaded section of the ball screw 1 is connected to a stop structure. A ball nut 2 is sleeved outside the ball screw 1. The front end of the ball nut 2 is connected to an end cover 3. A caliper housing 4 is sleeved outside the ball nut 2. A number of guiding convex platforms 6 or guiding grooves 5 are connected to the outside of the ball nut 2, and the ball nut 2 and the guiding convex platforms 6 are of an integral structure. The outer edge of the threaded section of the ball screw 1 is provided with a number of closed circulation circuits. A number of steel balls are arranged in the circulation circuits. The stop structure is an axial stop structure 7 or a circumferential stop structure 9.

[0027] The circumferential stop structure 9 is a frustum-shaped convex structure, and the circumferential stop structure 9 is located inside the end cover 3. The circumferential stop structure 9 is arranged in cooperation with the anti-rotation structure 8.

[0028] The anti-rotation structure 8 is connected to the end of the threaded section of the ball screw 1, and the connection mode of the anti-rotation structure 8 and the threaded section of the ball screw 1 is one of screw connection, riveting connection, interference fit connection, welding connection, and integral connection.

[0029] The circumferential stop structure 9 and the anti-rotation structure 8 are arranged in a double-convex type or a one-convex-one-concave type.

[0030] The connection mode of the circumferential stop structure 9 and the end cover 3 is one of screw connection, riveting connection, interference fit connection, welding connection, and integral connection.

[0031] The connection mode of the end cover 3 and the front end of the ball nut 2 is one of interference fit connection, screw connection, welding connection, and integral connection.

[0032] The connection mode of the guiding convex platforms 6 and the ball nut 2 is one of integral connection, screw connection, riveting connection, welding connection, and interference fit connection.

[0033] At the front end of the ball nut 2, there is an end cap 3. The end cap 3 is connected to the ball nut 2 by interference fit, threading, or welding, or the end cap 3 is integrated with the ball nut 2. A circumferential stop structure 9 is designed on the inner side of the end cap 3. The circumferential stop structure 9 is connected to the end cap 3 by threading, riveting, interference fit, or welding, or the circumferential stop structure 9 is integrated with the end cap 3. A rotation prevention structure 8 is also designed on the front end face of the ball screw 1. The rotation prevention structure 8 is connected to the ball screw 1 by threading, riveting, interference fit, or welding, or the rotation prevention structure 8 is integrated with the ball screw 1. The circumferential stop structure 9 and the rotation prevention structure 8 can both be of a double-convex type or a one-convex-one-concave type. After the ball nut 2 retracts to a certain position, the circumferential stop structure 9 and the rotation prevention structure 8 come into contact, and the ball nut 2 completes the return position. The end cap 3 can not only bear a torque of several Newton-meters from the ball screw 1 but also seal the ball nut 2. Several guiding convex platforms 6 or guiding grooves 5 are designed on the outer surface of the ball nut 2. The guiding convex platforms 6 or guiding grooves 5 and the ball nut 2 are of an integrated structure, or the guiding convex platforms 6 are connected to the ball nut 2 by threading, riveting, welding, or interference fit. The guiding part of the caliper housing 4 and the ball nut 2 is a one-convex-one-concave combination. When the caliper receives an instruction to enter the maintenance mode, speed control is applied to the motor, and its maximum and minimum torques are restricted. And the angular deceleration of the motor is subjected to least squares fitting. When the ball nut 2 retracts until the rotation prevention structure 8 contacts the circumferential stop structure 9, which is commonly known as hitting the bottom, the angular deceleration of the motor will increase, and the actual torque of the motor will also increase, and the force sensor shows an increase in value. When the above conditions are met simultaneously, it can be considered that the ball nut 2 has retracted to the bottommost position.

[0034] When the friction plate needs to be replaced, the dry brake is made to enter the maintenance mode through the diagnostic instruction of the ECU.

[0035] After receiving the maintenance mode instruction, the dry brake adopts a speed control method. To prevent the actual speed from being too large and causing the system to have a large kinetic energy, combined with the response time required by the maintenance mode, the target speed of the motor is set as the target parameter THRspeed. And the actual maximum and minimum torques of the motor are restricted. Continuously monitor the clamping force value, the position of the permanent magnet synchronous motor, the actual torque, and the angular deceleration.

[0036] When there is an increase in angular deceleration, a slowdown in the position growth slope, an increase in the actual torque slope, and an increase in the clamping force value, it is determined that the ball screw has hit the bottom.

[0037] When it is determined that the ball screw has hit the bottom, position control is applied to the motor with the current position as the target position.

Claims

1. A ball screw protection structure applied to an electromechanical brake, comprising a ball screw (1), a ball nut (2), and a caliper housing (4). The ball screw (1) is integrally formed by a screw rod body and a screw thread section of the screw rod, and is characterized in that: The front end of the threaded section of the ball screw (1) is integrally connected to the screw rod body. The end of the threaded section of the ball screw (1) is connected to a stop structure. A ball nut (2) is sleeved outside the ball screw (1). The front end of the ball nut (2) is connected to an end cover (3). A caliper housing (4) is sleeved outside the ball nut (2); several guide bosses (6) or guide grooves (5) are connected to the outside of the ball nut (2), and the ball nut (2) and the guide bosses (6) are of an integral structure; several closed circulation circuits are provided on the outer edge of the threaded section of the ball screw (1); several steel balls are provided in the circulation circuits; the stop structure is an axial stop structure (7) or a circumferential stop structure (9).

2. The ball screw protection structure applied to an electro-mechanical brake according to claim 1, characterized in that: The axial stop structure (7) is an arc-shaped convex structure, and the axial stop structure (7) is located at the central position of the end of the threaded section of the ball screw (1).

3. A ball screw protection structure applied to an electromechanical brake according to claim 1 or 2, characterized in that: The connection method between the axial stop structure (7) and the end of the threaded section of the ball screw (1) is one of threaded connection, riveted connection, interference fit connection, welded connection, and integral connection.

4. The ball screw protection structure applied to an electro-mechanical brake according to claim 1, characterized in that: The circumferential stop structure (9) is a frustum-shaped convex structure, and the circumferential stop structure (9) is located inside the end cover (3); the circumferential stop structure (9) is arranged in cooperation with the anti-rotation structure (8).

5. The ball screw protection structure applied to an electromechanical brake according to claim 4, characterized in that: The anti-rotation structure (8) is connected to the end of the threaded section of the ball screw (1), and the connection method between the anti-rotation structure (8) and the threaded section of the ball screw (1) is one of threaded connection, riveted connection, interference fit connection, welded connection, and integral connection.

6. The ball screw protection structure applied to an electromechanical brake according to claim 4, characterized in that: The circumferential stop structure (9) and the anti-rotation structure (8) are arranged in a double-convex type or a one-convex-one-concave type.

7. A ball screw protection structure applied to an electro-mechanical brake according to claim 1 or 4, characterized in that: The connection method between the circumferential stop structure (9) and the end cover (3) is one of threaded connection, riveted connection, interference fit connection, welded connection, and integral connection.

8. A ball screw protection structure applied to an electro-mechanical brake according to claim 1, characterized in that: The connection method between the end cover (3) and the front end of the ball nut (2) is one of interference fit connection, threaded connection, welded connection, and integral connection.

9. A ball screw protection structure applied to an electro-mechanical brake according to claim 1, characterized in that: The connection method between the guide boss (6) and the ball nut (2) is one of integral connection, threaded connection, riveted connection, welded connection, and interference fit connection.

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