Anti-locked-rotor structure of electric control booster

Abstract

The utility model relates to an anti-locked-rotor structure of an electric control booster, and belongs to the field of electric control boosters in a new energy automobile braking system. The motor, the ball screw and the hydraulic cylinder take the valve body as a carrier, the axis of the motor, the ball screw and the hydraulic cylinder are coaxially fixed on the valve body through screws or fastening glue, a piston is assembled on the ball screw, a rotor bottom hole in the motor is in radial interference fit with the tail end of a lead screw of the ball screw, the axial end face of the motor is limited, and a gap H is reserved between the bottom end face of a nut and the bottom end face of the rotor. The electric control booster has the advantages that the structure is novel, the locked-rotor problem that a nut and a motor rotor can be separated only by large torque or cannot be separated under a certain motor torque in the forward stroke due to tightening torque generated by contact friction is solved, the manufacturing and assembling process is easy to implement, the electric control booster can be applied to electric control booster products with ball screws, and the electric control booster is suitable for large-scale popularization and application. Conventional braking, brake-by-wire, active collision avoidance, self-adaptive cruising, intelligent driving and braking energy returning of the vehicle are achieved.

Description

Technical Field

[0001] This utility model belongs to the field of electric control boosters in the braking system of new energy vehicles, and specifically relates to an anti-stall structure for an electric control booster. Background Technology

[0002] With the development of new energy vehicles, traditional internal combustion engines are gradually being replaced by batteries. Vacuum boosters used in traditional automotive braking systems are gradually being phased out, replaced by electronically controlled power boosters for new energy vehicles. Electronically controlled power boosters use a controller that receives signals from displacement sensors to detect the brake pedal travel. Simultaneously, the controller controls the output torque of the motor to transmit force to the hydraulic cylinder. The brake fluid in the hydraulic cylinder then transmits hydraulic pressure to the brake wheel cylinders through brake lines, achieving the purpose of braking the entire vehicle. Currently, products in the industry use hollow motors that transmit torque to the hydraulic cylinder based on structures such as gears and racks, worm gears, and ball screws. Among these, the transmission structure with the ball screw as the main component is relatively simple and has high transmission efficiency.

[0003] The torque and inertia generated by the high-speed rotation of the ball screw driven by the hollow motor cause significant friction between the bottom face of the nut and the bottom face of the motor, resulting in a stall. This leads to excessive torque output from the motor during subsequent cycles, or the motor rotor being unable to drive the screw to overcome the friction, causing product failure. To prevent stalling, both the bottom faces of the hollow motor rotor and the ball screw nut are typically designed with bosses. These bosses act as a stop before the two surfaces come into contact, preventing contact and thus avoiding the stalling problem. See also... Figure 6 However, because the boss B on the bottom end face of the ball screw nut is too small, there is a risk of damage during impact; while the boss A on the rotor is too large, causing the rotor's center of gravity to shift, resulting in unstable rotation. At the same time, the processability of machining the boss at the bottom of the rotor hole is poor. Summary of the Invention

[0004] This utility model provides an anti-stalling structure for an electronically controlled power booster to solve the stalling problem caused by the contact and friction between the rear end face of the ball screw nut and the bottom surface of the motor rotor during the return stroke, resulting in a tightening torque. This leads to a situation where the nut and motor rotor require a large torque to disengage during the outward stroke, or cannot disengage under a certain motor torque.

[0005] The technical solution adopted by this utility model is as follows: it includes a motor, a ball screw, a hydraulic cylinder and a valve body. The motor, ball screw and hydraulic cylinder are fixed to the valve body with the valve body as the carrier and the shaft is coaxial with the valve body by screws or fastening glue. A piston is installed on the ball screw. The rotor bottom hole inside the motor is radially interference-fitted with the end of the ball screw. The axial end face is limited. A gap H is left between the bottom end face of the nut and the bottom end face of the rotor.

[0006] The motor mentioned is a coreless motor.

[0007] The rotor and the lead screw are fixedly connected by screws to ensure that the motor rotor and the lead screw rotate synchronously.

[0008] The ball screw includes a screw and a nut, wherein the nut is threadedly connected to the screw, and the front end of the screw has a ball head and an external hexagon.

[0009] The external hexagonal shape is used to position and prevent rotation of the lead screw when assembling the lead screw and motor rotor and tightening the screws.

[0010] The diameter of the ball head is slightly smaller than the diameter of the ball socket on the front end face of the piston's inner bore.

[0011] The piston's inner bore front end face has a ball-and-socket structure, with the ball head contacting and fitting with the ball-and-socket, and the piston's rear end is threadedly connected to the nut.

[0012] The valve body contains hydraulic channels that connect to the reservoir, solenoid valve, simulator cylinder, pedal simulator, and vehicle brake lines.

[0013] The advantages of this invention are its novel structure. When the piston and nut return to the starting point, the piston's ball socket contacts and limits contact with the ball head on the lead screw. A certain gap exists between the rear end face of the nut and the bottom surface of the motor rotor, thus avoiding contact friction that generates tightening torque, preventing the nut from requiring a large torque to disengage from the motor rotor during the outward stroke, or failing to disengage under a certain motor torque, leading to stalling. Compared to previous products with boss structures, this structure avoids the risk of damage from excessively small bosses upon impact, and also avoids the problem of rotor center of gravity shift and unstable rotation caused by excessively large bosses on the rotor. It also solves the problem of poor manufacturability in machining bosses at the bottom of the rotor hole, and the manufacturing and assembly processes are easier to implement. It can be applied to electric power steering products with ball screws to achieve vehicle conventional braking, brake-by-wire braking, active collision avoidance, adaptive cruise control, intelligent driving, and brake energy recovery. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the structure of this utility model;

[0015] Figure 2 This is a schematic diagram of the structure of the ball screw of this utility model;

[0016] Figure 3 yes Figure 2 The left view;

[0017] Figure 4 This is a schematic diagram of the piston structure of this utility model;

[0018] Figure 5 This is a schematic diagram of the gap between the bottom end face of the motor rotor and the bottom of the nut in this utility model.

[0019] Figure 6 This is a schematic diagram of a conventional anti-blocking structure using bosses. Detailed Implementation

[0020] See Figure 1 , 5 The system includes a motor 1, a ball screw 2, a hydraulic cylinder 3, and a valve body 4. The motor 1, ball screw 2, and hydraulic cylinder 3 are mounted on the valve body 4 with their axes coaxial and fixed to the valve body 4 by screws or fasteners. A piston 3 is mounted on the ball screw 2. The rotor 1.1 bottom hole inside the motor 1 has a radial interference fit with the tail end of the ball screw 2.1 and is axially limited by the end face. A gap H is left between the bottom end face 2.2.1 of the nut and the bottom end face 1.1.1 of the rotor.

[0021] See Figure 1 The motor 1 mentioned is a coreless motor.

[0022] See Figure 1 To prevent the rotor 1.1 from becoming loose, the tail end of the lead screw 2.1 is fixedly connected to the rotor 1.1 by screw 1.2 to ensure that the motor rotor 1.1 and the lead screw 2.1 rotate synchronously.

[0023] See Figure 2 , 3 The ball screw 2 includes a screw 2.1 and a nut 2.2, wherein the nut 2.2 is threadedly connected to the screw 2.1, and the front end of the screw 2.1 has a ball head 2.1.1 and an external hexagonal head 2.1.2.

[0024] See Figure 2 The hexagonal joint 2.1.2 is used to position and prevent rotation of the lead screw 2.1 when assembling the lead screw 2.1 and the motor rotor 1.1 and tightening the screw 1.2.

[0025] The spherical diameter of the ball head 2.1.1 is slightly smaller than the diameter of the ball socket 3.1 on the front end face of the inner bore of the piston 3.

[0026] See Figure 4 The piston 3 has a ball socket 3.1 structure on the front end face of the inner hole. In the product assembly state, the ball head 2.1.1 contacts and engages with the ball socket 3.1, and the rear end of the piston 3 is threadedly connected to the nut 2.2.

[0027] The valve body 4 contains a hydraulic channel that connects to the reservoir, solenoid valve, simulator cylinder, pedal simulator and vehicle brake lines.

[0028] Working principle

[0029] When the product is not in operation, the liquid pressure in the hydraulic cylinder 5 is zero. When the hydraulic cylinder needs to build up pressure on the outward stroke and release pressure on the return stroke, the controller 6 controls the input current of the motor 1, causing the motor rotor 1.1 to rotate counterclockwise or clockwise. At the same time, it drives the lead screw 2.1 on the motor rotor shaft to rotate, and transmits the force to the piston 3 connected to it through the nut 2.2 to move linearly, thereby realizing the hydraulic cylinder's pressure building up on the outward stroke and pressure release on the return stroke.

[0030] When piston 3 and nut 2.2 return to their initial assembly state after pressure relief, nut 2.2 reaches its limit size during the return stroke when the ball end 2.1.1 of screw 2.1 contacts and limits the contact with the ball socket 3.1 of piston 3. At this time, there is a gap H between the bottom end face 2.2.1 of nut and the bottom end face 1.1.1 of rotor. The two will not have contact friction to generate tightening torque. When piston needs to move again to build up pressure, it will not be unable to rotate due to the previously generated friction tightening torque, thus preventing a stall phenomenon.

Claims

1. An anti-stall structure for an electronically controlled power booster, characterized in that: It includes a motor, a ball screw, a hydraulic cylinder, and a valve body. The motor, ball screw, and hydraulic cylinder are mounted on the valve body as a carrier, with their axes coaxial and fixed to the valve body by screws or fasteners. A piston is mounted on the ball screw. The rotor bottom hole inside the motor has a radial interference fit with the tail end of the ball screw, and the axial end face is limited. A gap H is left between the bottom end face of the nut and the bottom end face of the rotor.

2. The anti-stall structure of an electronically controlled booster according to claim 1, characterized in that: The motor mentioned is a coreless motor.

3. The anti-stall structure of an electronically controlled booster according to claim 1, characterized in that: The rotor and the lead screw are fixedly connected by screws to ensure that the motor rotor and the lead screw rotate synchronously.

4. The anti-stall structure of an electronically controlled booster according to claim 1, characterized in that: The ball screw includes a screw and a nut, wherein the nut is threadedly connected to the screw, and the front end of the screw has a ball head and an external hexagon.

5. The anti-stall structure of an electronically controlled booster according to claim 4, characterized in that: The external hexagonal shape is used to position and prevent rotation of the lead screw when assembling the lead screw and motor rotor and tightening the screws.

6. The anti-stall structure of an electronically controlled booster according to claim 4, characterized in that: The diameter of the ball head is slightly smaller than the diameter of the ball socket on the front end face of the piston's inner bore.

7. The anti-stall structure of an electronically controlled booster according to claim 6, characterized in that: The piston's inner bore front end face has a ball-and-socket structure, with the ball head contacting and fitting with the ball-and-socket, and the piston's rear end is threadedly connected to the nut.

8. The anti-stall structure of an electronically controlled booster according to claim 1, characterized in that: The valve body contains hydraulic channels that connect to the reservoir, solenoid valve, simulator cylinder, pedal simulator, and vehicle brake lines.

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