KR20160136647A - Rear wheel steering and parking brake integrated system for a vehicle - Google Patents

Abstract

The present invention relates to a rear wheel steering and parking brake integrated system for a vehicle, which can simultaneously realize the rear wheel steering function and the parking brake function of a vehicle by using one actuator. The rear wheel steering and parking brake integrated system for a vehicle according to the present invention comprises: a rear wheel steering unit for steering the rear wheel of the vehicle; a parking brake unit operated when the vehicle is parked; a motor unit selectively connected to the rear wheel steering unit or the parking brake unit to selectively drive the rear wheel steering unit or the parking brake unit; and a solenoid for varying the position of the motor unit to be selectively connected to the rear wheel steering unit or the parking brake unit.

Description

Technical Field [0001] The present invention relates to a rear wheel steering and parking brake integrated system for a vehicle,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rear wheel steering and parking brake integrated system of a vehicle that can simultaneously implement a rear wheel steering function and a parking brake function of a vehicle by using one actuator.

Generally, the steering apparatus applied to a vehicle is configured to be able to steer through a front wheel in most cases. In this case, when turning at high speed, the centrifugal force is proportional to the turning speed and inversely proportional to the turning radius As the magnitude of force acts on the outside of the turn, the driver must increase the deceleration or turning radius.

In order to improve the turning performance of the vehicle, a technique for laying a steering device on rear wheels in addition to the front wheels has been developed in recent years because increasing the deceleration or turning radius during turning of the vehicle is not effective. This technology is applied to some vehicles.

In the case of such a rear wheel steering vehicle, since there is no column or steering wheel provided in the front wheel steering, CAN (Controller Area Network) communication (communication between the microcontroller or devices without a host computer in the vehicle The control of the rear screw of the vehicle is controlled by controlling the lead screw or the ball screw and the motor in accordance with the running condition of the vehicle.

For example, when the vehicle is at a low speed, the rear wheel steering angle is controlled in the opposite direction to the front wheel steering angle to reduce the turning radius of the vehicle. When the vehicle is at high speed, the rear wheel steering angle is controlled in the same direction as the front wheel steering angle, So as to improve stability.

Such a rear wheel steering apparatus was driven by a hydraulic device in the early stage, but recently, a motor is used as a driver in order to reduce the weight, simplify the apparatus and improve the flexibility of the control.

That is, in the conventional rear wheel steering apparatus, a driving shaft such as a lead screw, a ball screw, or the like is screwed to a nut rotated by a motor, and the driving shaft is linearly moved by rotating the nut, so that the direction of the rear wheel linked to the driving shaft is adjusted.

On the other hand, a vehicle equipped with such rear wheel steering apparatus is provided with a parking brake for braking the rear wheel of the vehicle so as to maintain the parking state when parking the vehicle.

In particular, in recent years, an electronic parking brake (EPB), which electronically controls driving of a parking brake, has been widely used to improve the driver's convenience.

The electronic parking brake is configured such that the electronic control device receives a detection signal from various sensors and then drives the motor based on the detection signal to cause the cable to be pulled or released by the driving force of the motor so as to generate or release the braking force to the rear wheel.

[0004] However, in a vehicle capable of steering the rear wheels to which the electronic parking brake is applied as described above, a motor for driving the rear wheel steering apparatus and a motor for driving the electronic parking brake are separately provided, There is a problem in that the cost increases due to an increase in the number of parts to be installed and the weight of the vehicle is increased and the layout of the vehicle is inevitably disadvantageous in consideration of the structure of the vehicle.

Korean Patent Publication No. 2013-0030635 (March 31, 2013) Korea Patent Registration No. 10-1176469 (August 17, 2012)

SUMMARY OF THE INVENTION Accordingly, the present invention has been made to solve the above-mentioned problems occurring in the prior art, and it is an object of the present invention to provide a vehicle capable of steering a rear wheel on which an electronic parking brake EPB is mounted, The rear wheel steering function and the parking brake function can be implemented at the same time, so that the number of parts to be installed in the vehicle can be minimized to reduce the cost, the weight can be reduced to improve the fuel efficiency of the vehicle, The present invention provides an integrated rear-wheel steering and parking brake system for a vehicle.

According to an aspect of the present invention, there is provided a rear wheel steering and parking brake integrating system for a vehicle, comprising: a rear wheel steering unit for steering rear wheels of a vehicle; a parking brake unit operated when the vehicle is parked; Or a solenoid which is selectively connected to the parking brake unit and selectively drives the rear wheel steering unit or the parking brake unit and a solenoid which varies the position of the motor unit so as to be selectively connected to the rear wheel steering unit or the parking brake unit .

At this time, the motor unit and the rear wheel steering unit are interlocked with each other during normal traveling of the vehicle, so that normal rear wheel steering is possible through the rear wheel steering unit, while the motor unit is engaged with the parking brake unit by the operation of the solenoid The brakes can be configured to operate.

In the rear wheel steering and parking brake integrated system according to the present invention, a worm wheel mounted on the motor unit side, a first worm nut mounted on the rear wheel steering unit side to rotate in engagement with the worm wheel, And a second worm nut which rotates in engagement with the worm wheel.

At this time, the solenoid is provided with a drive shaft capable of moving forward and backward, and the drive shaft is connected to a motor provided on the motor unit side, so that the position of the motor can be changed by moving the drive shaft back and forth.

According to the structure of the rear wheel steering and parking brake integrating system according to the present invention, in a vehicle capable of rear wheel steering equipped with an electronic parking brake, it is possible to simultaneously implement the rear wheel steering function and the parking brake function of the vehicle by using one motor Thereby minimizing the number of parts to be installed in the vehicle, thereby reducing the production cost of the vehicle and reducing the weight of the vehicle, thereby improving the fuel economy of the vehicle. In addition, there is an effect that the degree of freedom in designing the interior of the vehicle can be improved as the number of parts to be installed decreases.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a configuration diagram showing the configuration of a rear wheel steering and parking brake integration system according to the present invention; FIG.
Fig. 2 is an operational state showing a state in which a motor unit is connected to a rear wheel steering unit when a rear wheel steering apparatus is operated according to the running of a vehicle. Fig.
3 is an operating state showing a state in which the motor unit is connected to the parking brake unit when the parking brake is operated during stopping of the vehicle.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a preferred embodiment of a rear wheel steering and parking brake integrated system of a vehicle according to the present invention will be described in detail with reference to the accompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a block diagram showing the overall configuration of a rear wheel steering and parking brake integration system of a vehicle according to the present invention; FIG.

Referring to FIG. 1, the rear wheel steering and parking brake integration system according to the present invention includes a rear wheel steering unit 100 provided for rear wheel steering of a vehicle, a parking brake unit 200 provided for a parking brake operation of the vehicle, A motor unit 300 selectively connected to the rear wheel steering unit 100 or the parking brake unit 200 to drive a rear wheel steering or a parking brake of the vehicle and a motor unit 300 for driving the rear wheel steering unit 100 And a solenoid 400 for varying a connecting position of the motor unit 300 so as to be selectively connected to the parking brake unit 200.

The rear wheel steering unit 100 is provided for steering the rear wheels of the vehicle. The rear wheel steering unit 100 includes a ball screw 140 connected to a link 160 connected to the right and left rear wheels of the vehicle and reciprocating in the longitudinal direction, And a first worm nut 120 that rotates in conjunction with the first worm nut 120. [

The first worm nut 120 has a screw-shaped worm formed on its outer circumferential surface and intermeshed with a worm wheel 340 coupled to the motor 320. The first worm nut 120 has an inner circumferential surface Threads are formed and intermeshed with the ball screw 140. A plurality of balls are interposed in the threaded portion of the first worm nut 120 engaged with the ball screw 140 to induce rolling friction when the first worm nut 120 rotates.

The first worm nuts 120 are rotated in the forward or reverse direction by receiving the rotational power from the motor 320 provided in the motor unit 300, The screw 140 moves linearly along the longitudinal direction, so that the steering operation of the rear wheel connected to the link 160 is performed.

At this time, the rear-wheel steering unit 100 is maintained in a continuously connected state with the motor unit 300, which is normally maintained in the traveling mode, so that normal rear wheel steering required for the running state of the vehicle is performed.

That is, when it is determined that the vehicle is running at a high speed while the vehicle is running, the ECU senses the vehicle speed and turning radius, and the ECU operates the motor 320 provided in the motor unit 300 to drive the rear wheel steering unit 100, The rear wheel steering is performed.

On the other hand, the parking brake unit 200 is a device that allows the vehicle to maintain the parking state by braking the rear wheels when parking the vehicle.

The parking brake unit 200 is applied with an electronic parking brake (EPB) which enables the parking brake to be automatically operated and released.

The electronic parking brake (EPB) receives a signal sensed by various sensors installed in the vehicle through an ECU and drives the motor unit 300 based on the signal. The cable 250 is pulled by the driving force of the motor unit 300 The braking force is generated or released from the left and right rear wheels.

The parking brake unit 200 is provided with a second worm nut 220 which rotates in engagement with the worm wheel 340 of the motor 320 and a second worm nut 220 which rotates in accordance with the rotation of the second worm nut 220 And a cable 250 that is relaxed or pulled when the ball screw 240 is linearly moved and operates or releases the parking brake.

The second worm nut 220 is formed with a worm in the form of a thread to be engaged with the worm wheel 340 of the motor 320 on the outer peripheral surface in the same manner as the first worm nut 120 provided in the rear wheel steering unit 100 And has an inner peripheral surface formed with threads so as to be mutually engaged with the ball screw 240.

At this time, a plurality of balls are interposed in an inner thread portion of the second worm nut 220 engaged with the ball screw 240, causing rolling friction.

The ball screw 240 is linearly moved in a state of being engaged with the second worm nut 220 when the second worm nut 220 is rotated and pulls or loosens the cable 250 to rotate the parking brake 260 Lock or unlock.

Accordingly, when the drive signal is inputted from the ECU to the motor 320, the motor 320 is rotated. As the second worm nut 220 engaged with the worm wheel 340 of the motor 320 rotates, the ball screw 240 rotates, And the cable 250 connected to the ball screw 240 is pulled or relaxed to actuate or release the parking brake 260.

At this time, a lead screw, which is a screw seal capable of realizing higher precision, may be applied in addition to the ball screw 240 provided in the parking brake unit 200.

When the parking brake unit 200 is in a state of being short-circuited with the motor unit 300 and is not operated normally during the time when the vehicle is maintained in the running state, And is driven by the power transmitted from the motor unit 300 by operating the motor unit 300 so that the parking brake 260 is operated.

The motor unit 300 includes a motor 320 for generating a rotational power and a worm wheel 340 coupled to the rotational shaft of the motor 320.

The worm wheel 340 is engaged with the first worm nut 120 provided in the normal rear wheel steering unit 100 in which the vehicle is maintained in a running state to transmit the rotational power of the motor 320 to the rear wheel steering unit 100 And is engaged with a second worm nut 220 provided in the parking brake unit 200 after being separated from the first worm nut 120 in operation of the parking brake so that the rotational power of the motor 320 is transmitted to the parking brake unit 200).

On the other hand, as mentioned above, the motor unit 300 maintains the connection state with the side of the normal rear wheel steering unit 100 in which the vehicle is maintained in the traveling state, so that the rear wheels can be steered while the vehicle is running. It is separated from the rear wheel steering unit 1000 side and then connected to the parking brake unit 200 side to enable the parking brake 260 to operate.

The connection position changing operation of the motor unit 300 in each of the above-described situations can be realized through the driving of the solenoid 400.

The solenoid 400 is a device provided to generate mechanical movement of the entire motor unit 300. When the current is supplied to a coil (not shown) inside the solenoid 400, the solenoid 400 drives the drive shaft 420 into the coil So as to vary the position of the motor unit 300 through the pulling operation.

That is, the solenoid 400 is provided with a driving shaft 420 for moving back and forth according to the supply or cutoff of current, and the end of the driving shaft 420 is fixed to the outer surface of the housing of the motor 320.

When a driving signal is applied to the solenoid 400 from the ECU, the magnetic field generated in the solenoid 400 causes the driving shaft 420 to move to the inside of the solenoid 400, And the position of the motor unit 300 is varied by the linear mechanical movement of the drive shaft 420. [

That is, the motor unit 300 engaged with the rear wheel steering unit 100 is separated from the rear wheel steering unit 100 by the driving force by the driving shaft 420 when the solenoid 400 is operated Rear parking brake unit 200 side.

The solenoid 400 is provided with an elastic member (spring) for pushing the drive shaft 420 back to the original initial position when the supply of current is interrupted, so that when the parking brake is released, The drive shaft 420 pushes the motor unit 300 back to its original position so that the motor unit 300 can maintain the continued connection with the rear wheel steering unit 100 again.

As described above, the present invention can selectively implement the rear wheel steering and parking brake functions by selectively changing the connecting position of the motor 320 through the solenoid 400 according to the driving situation of the vehicle.

As described above, according to the present invention, the rear wheel steering function and the parking brake function of the vehicle can be implemented simultaneously using one driving motor 320 according to a necessary situation. Therefore, the functions of the rear wheel steering and the parking brake There is no need to install motors individually to implement them, which can reduce production costs.

Further, as the number of parts to be installed in the vehicle is reduced, the total weight of the vehicle can be reduced to improve the fuel efficiency of the vehicle, and the design freedom in the vehicle can be improved.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be construed as limited to the embodiments set forth herein. Will be possible.

100: rear wheel steering unit 120: ball nut gear
140, 240: Ball Screw 160: Link
200: Parking brake unit 220: Worm nut gear
260: Brake 300: Motor unit
320: Worm wheel 400: Solenoid

Claims (4)

A rear wheel steering unit (100) for steering the rear wheels of the vehicle;
A parking brake unit 200 operated upon parking of the vehicle;
A motor unit (300) selectively connected to the rear wheel steering unit (100) or the parking brake unit (200);
A solenoid (400) for varying the position of the motor unit (300) so as to be selectively connected to the rear wheel steering unit (100) or the parking brake unit (200);
And a rear wheel steering and parking brake integrated system of the vehicle.
2. The vehicle rear wheel steering and parking brake integrated system of claim 1, wherein the solenoid (400) is operated only when the vehicle is parked and drives the parking brake unit (200) through the motor unit .
The method according to claim 1,
A worm wheel 340 provided in the motor unit 300;
A first worm nut (120) provided in the rear wheel steering unit (100) and rotated by engaging with the worm wheel (340);
A second worm nut (220) provided on the parking brake unit (200) and rotated by engaging with the worm wheel (340);
And a rear wheel steering and parking brake integrated system of the vehicle.
The method according to claim 1,
The solenoid 400 is provided with a drive shaft 420 capable of moving forward and backward and the drive shaft 420 is connected to a motor 320 provided in the motor unit 300, Wherein the position of the motor (320) is variable.

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