Steering shock absorbing structure for in-wheel motor and method thereof

Abstract

To provide a steering impact absorption structure for an in-wheel motor and a method thereof.SOLUTION: There is provided a steering impact absorption structure for an in-wheel motor comprising: a steering input part for sensing a steering angle of a steering wheel; a steering unit which is fixed to one end of the steering input part, and is configured to steer a wheel according to a steering angle of the steering input part; a tilt unit which is coupled to the steering unit at one end, is coupled to the wheel at the other end, and is tilted with the steering unit as a standard; and a control part for selectively driving the tilt unit.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a steering shock absorbing structure and method for an in-wheel motor, and more particularly to a steering shock absorbing structure for an in-wheel motor that can minimize damage to the in-wheel motor by applying a new tilting unit to secondarily absorb impacts above a predetermined limit. The present invention also relates to a steering shock absorbing method for an in-wheel motor that can selectively drive the tilting unit by calculating the amount of impact detected by multiple sensors. [Background technology]

[0002] Generally, automobiles are driven by transmitting power to the road surface through the tires. This is achieved by controlling the movement of the front or rear wheels of the vehicle through a steering device operated by a driver in the driver's seat. A steering wheel used as such a steering device requires a large amount of force to turn, so a power steering system that uses an electric motor and hydraulic power as auxiliary power is well known and used. An electric power steering (MDPS) system additionally includes an electric motor connected to the rotating shaft of the steering wheel. The rotational force provided by the electric motor is used as auxiliary rotational force for the steering wheel, making it easy to rotate the steering wheel.

[0003] However, in the past, when the driver turned the steering wheel, the steering gear pinion rotated at the same angle, and after that, the helical gear converted it into a reciprocating motion, which then determined the steering angle of the tires. Because everything from the steering wheel to the steering gear was fixed as a solid type, once the hardware specifications were determined, the steering response of the vehicle was also determined.

[0004] As a result, the steering wheel responsiveness is not changed according to the vehicle's speed, driving tendency, etc., making it difficult to satisfy the driver's requirements and providing optimized responsiveness under various driving conditions.Recently, as research into eco-friendly cars has become more active, in-wheel motor vehicles, in which a motor is directly installed within the rim of a wheel on which a tire is mounted so that the motor's power is directly transmitted to the wheel, have been gaining attention because they can omit intermediate power transmission devices such as a reducer or differential gear, thereby reducing the vehicle weight and reducing energy loss in the power transmission process.

[0005] The advantage of using electrically operated in-wheel motors is not only environmentally friendly, but also structurally advantageous in that it allows the left and right wheels to move independently. In-wheel motor systems, steering motors mounted on each wheel replace the conventional steering gear structure, increasing the freedom of vehicle movement and also forming the steering system structure for autonomous vehicles. However, replacing mechanical parts with electrical parts leaves parts vulnerable to external impacts, which poses the risk of safety issues.

[0006] Specifically, an independently controlled steering system for in-wheel motors is equipped with a motor that handles steering functions for each front wheel, allowing for greater freedom in achieving driving performance by freely controlling the toe angle during bumps and rebounds, and the inner / outer wheel angles during cornering, which were previously difficult to achieve due to mechanical constraints. However, the absence of mechanical constraints between the wheels and steering system creates the challenge of having to rely on the motor's operating force to withstand impact loads that were previously supported by the rigidity of the steering gear and other structures themselves. When a large impact is transmitted from the road surface, the impact load exceeds the limit of the motor's operating force, causing the steering angle of each wheel to momentarily deform to an angle that is difficult to control, creating the risk of an accident.

[0007] In addition, the drive motor inside the wheel may be damaged by impact and become inoperable. This could result in a loss of steering control function due to impact with the road surface, posing a safety issue. Therefore, a steering shock absorber (SSA) is needed that can ensure driving stability even when using an in-wheel motor. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Korean Patent Registration No. 10-1964373 Summary of the Invention [Problem to be solved by the invention]

[0009] An object of the present invention is to provide a steering shock absorbing structure for an in-wheel motor that can minimize damage to the in-wheel motor by applying a tilt unit to secondarily absorb impacts above a predetermined limit. Another object of the present invention is to provide a steering shock absorbing method for an in-wheel motor that can selectively drive a tilt unit by calculating the amount of impact detected by a plurality of sensors. [Means for solving the problem]

[0010] The steering shock absorbing structure for an in-wheel motor according to the present invention includes a steering input part that detects a steering angle of a steering wheel, a steering unit that is fastened to the steering input part and configured to steer the wheel according to the steering angle of the steering input part, a tilting unit that has one end connected to the steering unit and the other end connected to the wheel and configured to be tilted based on the steering unit, and a control part that selectively drives the tilting unit.

[0011] The steering unit is characterized by including a steering motor connected to the steering input portion and configured to rotate the tilting unit, and a steering angle sensor connected to the steering motor based on a steering shaft and configured to detect whether the steering angle input to the steering input portion matches the rotation angle of the steering motor.

[0012] The tilt unit includes a tilt yoke having one end fastened to a steering unit, a tilting portion housing fixed to the wheel and configured to rotate and tilt around a tilting axis located on the other side of the tilting yoke, a tilt braking device located between the tilting portion housing and the tilting yoke and configured to selectively fix the tilting portion housing, a tilt shock absorber configured to have one end connected to the tilting yoke and the other end connected to the tilting portion housing, and a tilt angle sensor linked to the tilt braking device and configured to detect the tilting angle of the tilting portion housing.

[0013] The vehicle may further include an acceleration sensor that detects an impact value of the vehicle, and when an impact value equal to or greater than a predetermined value is applied to the acceleration sensor, the steering angle sensor is configured to detect whether the steering angle input to the steering input unit matches the rotation angle of the steering motor.

[0014] The control unit controls the tilt braking device to fix the tilt portion housing when the vehicle is in a driver-controllable state.

[0015] The control unit controls the tilt braking device to release the fixation of the tilt portion housing when the vehicle is in a state where the driver cannot control it.

[0016] The tilting portion housing is configured to be tilted based on the tilting yoke, and the tilting shock absorber is compressed.

[0017] When the driver's uncontrollable state is released, the tilting portion housing is restored by the elastic restoring force of the tilting shock absorber.

[0018] The tilting portion housing is configured so that tilting is released based on the tilting yoke, and the tilt braking device is fixed.

[0019] The vehicle may further include an in-wheel motor connected to the tilt unit and applying a driving force to the wheel independently.

[0020] The steering shock absorbing method for an in-wheel motor according to the present invention includes the steps of: using an acceleration sensor to detect whether a predetermined impact value or more has been applied; if the predetermined impact value or more has been applied, a control unit to determine whether the driver can control the vehicle; and if the control unit determines that the driver cannot control the vehicle, releasing a tilt braking device; using a tilt angle sensor to detect whether the tilting unit housing has been tilted within a predetermined tilt limit angle; if the tilting unit housing has been tilted within the predetermined tilt limit angle, the control unit, with the tilt braking device released, adjusts the steering angle input to the steering input unit to match the rotation angle of the steering motor; when the control unit has completed adjustment so that the steering angle input to the steering input unit and the rotation angle of the steering motor match, using the tilt angle sensor to detect whether the tilting unit housing has been restored; and if the tilt angle sensor detects that the tilting unit housing has been restored, locking the tilt braking device.

[0021] The step of the control unit determining whether the driver controllable state is further characterized by including the steps of: determining whether a rotation angle of the steering motor corresponding to the input steering angle is the same; and, if the steering angle and the rotation angle are not the same, determining whether a current torque applied from the steering motor is equal to or less than a predetermined limit torque of the steering motor; determining that the driver controllable state is in effect if the current torque applied from the steering motor is equal to or less than the predetermined limit torque of the steering motor; and determining that the driver controllable state is in effect if the current torque applied from the steering motor exceeds the predetermined limit torque of the steering motor.

[0022] The step of determining that the control unit is in a driver-controllable state further includes a step of the control unit adjusting the steering angle input to the steering input unit so that it matches the rotation angle of the steering motor.

[0023] The method further includes the steps of: detecting whether the tilting unit housing has been tilted within a predetermined tilt limit angle; locking the tilt braking device if the tilting unit housing is tilted beyond the predetermined tilt limit angle; adjusting the steering angle input to the steering input unit and the rotation angle of the steering motor by the control unit so that they coincide; releasing the locking of the tilt braking device when the adjustment is completed so that the steering angle input to the steering input unit and the rotation angle of the steering motor coincide; detecting whether the tilting unit housing has been restored by the tilt angle sensor; and locking the tilt braking device if the tilting unit housing has been restored. [Effects of the Invention]

[0024] The present invention has the following effects. First, the tilt shock absorber secondarily absorbs the impact transmitted from the road surface, minimizing damage to the in-wheel motor. Second, the control unit calculates the amount of impact and selectively drives the tilting unit, ensuring steering stability in normal driving conditions, and when an impact greater than a predetermined amount is applied, absorbing all impacts in the front-to-back and up-to-down directions, preventing damage to the in-wheel motor. [Brief explanation of the drawings]

[0025] [Figure 1] 1 is a diagram illustrating the configuration of a steering shock absorbing structure for an in-wheel motor according to the present invention. [Figure 2] 1 is an overall perspective view of a steering shock absorbing structure for an in-wheel motor according to the present invention; [Figure 3] 1 is a diagram showing the detailed configuration of a steering unit and a tilting unit of a steering shock absorbing structure for an in-wheel motor according to the present invention. FIG. [Figure 4] 1 is a diagram showing a state in which the steering shock absorbing structure for an in-wheel motor according to the present invention can be controlled by a driver. FIG. [Figure 5] 1 is a diagram showing a state in which the steering shock absorbing structure for an in-wheel motor according to the present invention is unable to be controlled by the driver; [Figure 6] 1 is a flowchart of a steering shock absorbing method for an in-wheel motor according to the present invention. [Figure 7] 1 is a flowchart illustrating a steering shock absorbing method for an in-wheel motor according to the present invention in a driver controllable state. [Figure 8] 10 is a flowchart illustrating a method for absorbing steering shock for an in-wheel motor according to the present invention when the tilt angle is outside the tilt limit angle. DETAILED DESCRIPTION OF THE INVENTION

[0026]

[0023] The present invention will be described in detail below with reference to the accompanying drawings, in which:

[0024] The present invention can be implemented in various forms, and the present invention is not limited to these embodiments.

[0027] Fig. 1 is a structural diagram of a steering shock absorbing structure for an in-wheel motor according to one embodiment of the present invention, and Fig. 2 is an overall perspective view of the steering shock absorbing structure for an in-wheel motor according to one embodiment of the present invention. Referring to Figs. 1 and 2, the steering shock absorbing structure for an in-wheel motor according to one embodiment of the present invention includes a steering input unit 200, a steering unit 300, a tilt unit 400, and a control unit 500. It also includes an in-wheel motor unit 700 and an acceleration sensor 600. The wheel 100 is configured to be steerable in response to operation of the steering wheel. The wheel 100 is separated from the vehicle body and configured to be rotatable in response to operation of the steering wheel.

[0028] The steering input unit 200 includes a steering wheel and is configured to detect the steering angle of the steering wheel. More preferably, the steering input unit 200 is configured to detect the steering angle of the steering wheel operated by the driver for driving control of the vehicle equipped with the in-wheel motor unit 700. That is, the steering input unit 200 is equipped with a steering wheel steering angle sensor that detects the steering angle of the steering wheel. The steering angle detected by the steering wheel steering angle sensor and input to the steering input unit 200 is transmitted to the control unit 500. The steering input unit 200 of the present invention is a concept that includes not only physical steering input means but also all electrical signals, and includes all components that can receive a steering request from a user or a control unit.

[0029] The steering unit 300 is fastened to one end of the steering input portion 200. More preferably, the steering input portion 200 is configured to interlock with a suspension lower arm 301 and a knuckle 302 as the steering unit 300. The steering unit 300 is configured to steer the wheel 100 in accordance with the steering angle of the steering input portion 200. The tilting unit 400 has one end connected to the steering unit 300 and the other end connected to the wheel 100. The tilting unit 400 is configured to be tilted based on the steering unit 300. The tilting unit 400 is connected to the wheel 100 and configured to tilt the wheel 100 up and down based on one surface of the steering unit 300 as the tilting unit 400 is driven. Specifically, when a road impact is transmitted to the wheel 100, the tilting unit 400 is driven, thereby rotating and tilting the wheel 100 in the direction opposite to the vehicle traveling direction.

[0030] The control unit 500 is configured to transmit and receive signals to and from the steering input unit 200, the steering unit 300, the tilting unit 400, the in-wheel motor unit 700, and the acceleration sensor 600. The control unit 500 is configured to selectively drive the tilting unit 400. Specifically, the control unit 500 selectively drives the tilting unit 400 depending on a normal driving state and an impact state to achieve steering stability and prevent damage to the in-wheel motor unit 700. The control unit 500 also controls the driving speeds of the in-wheel motor units 700 mounted on the left and right wheels 100 to be different from each other depending on the steering angle of the steering wheel detected by the steering wheel steering angle sensor. That is, the control unit 500 is configured to control the in-wheel motor unit 700 depending on the steering angle input to the steering input unit 200.

[0031] Torques are applied to the left and right in-wheel motor units 700 differently based on signals from the control unit 500, so that the left and right in-wheel motor units 700 are driven at different rotational speeds. Therefore, a speed difference between the left and right wheels 100 can be generated due to the difference in driving speed between the left and right in-wheel motor units 700. The speed difference between the left and right wheels 100 generates a steering angle in which the left and right wheels 100 rotate by the same angle in one direction. The in-wheel motor unit 700 is configured to be connected to the tilting unit 400. Preferably, the in-wheel motor unit 700 is located between the wheels 100 and the tilting unit 400. The in-wheel motor unit 700 is configured to apply driving force independently to each wheel 100. The in-wheel motor unit 700 is configured to move integrally with each wheel 100. The in-wheel motor units 700 are disposed near the left and right wheels 100, respectively, and transmit rotational driving force for direct driving of the left and right wheels 100. The in-wheel motor unit 700 is controlled by the control unit 500 in accordance with the steering angle input to the steering input unit 200 .

[0032] The acceleration sensor 600 is configured to detect a vehicle impact. Preferably, when an impact equal to or greater than a predetermined value is applied to the acceleration sensor 600, the tilt unit 400 is selectively activated. In one embodiment, the predetermined impact value is 2.5 G. The predetermined impact value varies depending on the type of wheel 100, and is not limited thereto. When a road impact is transmitted to the wheel 100 of the vehicle, a suspension shock absorber connected to the knuckle 302 of the steering unit 300 primarily absorbs the vertical impact. When the tilt unit 400 is activated, the tilt unit 400 secondarily absorbs the longitudinal and vertical impacts. Specifically, when an impact transmitted to the wheel 100 during driving is transmitted through the knuckle 302, the vertical impact is absorbed by the suspension shock absorber. The vertical and longitudinal impacts not absorbed by the suspension shock absorber are absorbed by the tilt shock absorber 440.

[0033] 3 shows detailed configurations of a steering unit 300 and a tilt unit 400 of a steering shock absorbing structure for an in-wheel motor according to an embodiment of the present invention. Referring to FIG. 3, the steering unit 300 is configured to include a steering motor 310 and a steering angle sensor 330. The tilt unit 400 is configured to include a tilt portion housing 410, a tilt brake disc 420a, a tilt brake caliper 420b, a tilt shock absorber 440, a tilt angle sensor 430, a tilt shaft 450, and a tilt yoke 340.

[0034] The tilt brake device 420 of the present invention includes any configuration that can selectively lock or unlock the tilt portion housing 430. In one embodiment of the present invention, the tilt brake disc 420a and the tilt brake caliper 420b are collectively referred to as the tilt brake device 420. The tilt brake device 420 refers to the tilt brake disc 420a and the tilt brake caliper 420b individually or collectively.

[0035] The steering motor 310 is connected to the steering input unit 200 and configured to rotate the tilt unit 400. Preferably, the steering motor 310 is connected to one end of the knuckle 302 and configured to rotate the tilt yoke 340 around the steering shaft 320 in response to a steering request input via the steering input unit 200. The steering motor 310 can be configured as an integrated motor and engine control unit (ECU) like an electric power steering (MDPS) power pack. The steering motor 310 performs overall steering control by exchanging signals with the steering angle sensor 330 and the tilt brake caliper 420b via the steering motor 310 ECU.

[0036] When the driver turns the steering wheel, a steering request input is applied to the steering input unit 200, and the steering motor 310 calculates a rotation angle corresponding to the steering request input to the steering input unit 200 and rotates the wheels 100 by calculating the rotation angle. When the torque applied to the steering shaft 320 from the road surface via the wheels 100 exceeds the maximum torque of the steering motor 310, the angle of the steering wheel operated by the driver and the rotation angle of the steering motor 310 do not correspond to each other. The steering angle sensor 330 is configured to be connected to the steering motor 310 based on the steering shaft 320. The steering angle sensor 330 is configured to detect the rotation angle of the steering shaft 320. The steering angle sensor 330 is also configured to detect whether the steering request input to the steering input unit 200 matches the rotation angle of the steering motor 310. The steering angle sensor 330 is configured to monitor in real time whether the angle of the steering wheel turned by the driver corresponds to the rotation angle of the wheel 100.

[0037] The tilting yoke 340 is configured so that one end thereof is fixed to the steering unit 300. Preferably, the steering shaft 320 passes through the tilting yoke 340 and is fixed to the steering input part 200. A tilting part housing 410 is located on one outer surface of the tilting yoke 340. More preferably, a tilting shaft 450 of the tilting part housing 410 is fastened to the other surface of the tilting yoke 340 so that the tilting part housing 410 rotates up and down on one surface of the tilting yoke 340 based on the tilting shaft 450. One surface of the tilting yoke 340 further includes a bearing at one end opposite the tilting shaft 450. The tilting part housing 410 is configured to rotate based on the tilting shaft 450 inserted into the tilting yoke 340. A steering angle sensor 330 and a steering motor 310 are located on the underside of the tilting yoke 340, centered on the steering shaft 320. Preferably, the tilting shaft 450 is located in the tilting unit housing 410. The tilting shaft 450 is inserted into the opening of the tilting yoke 340, so that the tilting unit housing 410 is configured to rotate up and down around the tilting shaft 450 with the outer surface of the tilting yoke 340 as the reference.

[0038] The tilting unit housing 410 is configured to be fixed to the wheel 100. Preferably, a lower end of the tilting unit housing 410 is fixed to an in-wheel motor unit 700 mounted on the wheel 100 to tilt the wheel 100. The tilting unit housing 410 is configured to rotate and tilt based on the tilting yoke 340. Preferably, the tilting unit housing 410 rotates based on a tilting shaft 450 fastened to the tilting yoke 340. The tilting brake disc 420a and the tilting brake caliper 420b of the tilting braking device 420 are configured to have an operating method similar to that of an electronic brake system (EBS) for braking a vehicle.

[0039] The tilting brake disc 420a is fixed to the tilting unit housing 410. The tilting brake disc 420a is configured to fix or rotate the tilting unit housing 410 using frictional force with the tilting brake caliper 420b. The tilting brake caliper 420b is fixed to the tilting yoke 340 and selectively contacts the tilting brake disc 420a. The tilting brake caliper 420b selectively comes into frictional contact with the tilting brake disc 420a in response to a signal from the control unit 500 that is generated by a road impact. As a result, the tilting brake disc 420a is selectively fixed or rotated relative to the tilting yoke 340. The tilting brake caliper 420b controls the tilting angle and load using frictional force with the tilting brake disc 420a. The tilting brake caliper 420b is in contact with the tilting brake disc 420a during normal driving, preventing the tilting unit housing 410 from tilting. This ensures steering stability and driving performance.

[0040] When a road impact is detected by the acceleration sensor 600 and the steering angle sensor 330, the braking force of the tilt brake device 420, i.e., the tilt brake caliper 420b and the tilt brake disc 420a, is released, causing the tilt unit housing 410 to rotate. One end of the tilt shock absorber 440 is connected to the tilt yoke 340, and the other end is connected to the tilt unit housing 410. The tilt shock absorber 440 absorbs the road impact when the tilt unit housing 410 tilts. Specifically, the tilt shock absorber 440 is compressed as the tilt unit housing 410 rotates during a road impact, and absorbs the impact using a spring and a damper.

[0041] The tilt angle sensor 430 senses the tilt angle of the tilting unit housing 410 in conjunction with the tilting brake caliper 420b. In one embodiment, when the tilting angle sensed by the tilting angle sensor 430 is 0 degrees, the tilting brake caliper 420b locks the tilting brake disc 420a. In another embodiment, when the tilting brake caliper 420b releases the tilting brake disc 420a, the tilting angle sensor 430 senses whether the tilting unit housing 410 has rotated beyond a predetermined tilt limit angle.

[0042] FIG. 4 illustrates a driver-controllable state of a steering shock absorption structure for an in-wheel motor according to one embodiment of the present invention. Referring to FIG. 4, when the vehicle is in a driver-controllable state, the control unit 500 controls the tilt brake disc 420a of the tilt brake device 420 to lock. The driver-controllable state refers to a state in which, when a road impact is present, the torque applied from the road surface to the steering axle 320 via the wheel 100 is within the maximum torque range of the steering motor 310. The control unit 500 can also control the tilt brake disc 420a of the tilt brake device 420 to lock even in a normal driving state without a road impact. In the driver-controllable state, the angle of the steering wheel operated by the driver corresponds to the rotation angle of the steering motor 310. In addition, in the driver-controllable state, the steering angle input to the steering input unit 200 is configured to match the rotation angle of the steering motor 310.

[0043] In the driver-controllable state, the suspension shock absorber is configured to move up and down to absorb impacts transmitted from the road surface. At this time, the tilt brake disc 420a of the tilt braking device 420 is fixed by the tilt brake caliper 420b, so the tilt unit 400 remains fixed. In the driver-controllable state, the operation of the tilt brake disc 420a is restricted so that the tilt unit 400 does not tilt, ensuring driver control stability.

[0044] The control unit 500 compares the rotation angle of the steering motor 310 detected by the steering angle sensor 330 with the steering angle input to the steering input unit 200 detected by the steering angle sensor of the steering wheel, and when the rotation angle of the steering motor 310 matches the steering angle input to the steering input unit 200, adjusts the steering angles of the left and right wheels 100 to steering angles that match the steering angle input to the steering input unit 200.

[0045] FIG. 5 illustrates a driver-uncontrollable state of a steering shock absorption structure for an in-wheel motor according to an embodiment of the present invention. Referring to FIG. 5, when the vehicle is in a driver-uncontrollable state, the control unit 500 controls the tilt brake disc 420a of the tilt brake device 420 to be released. The driver-uncontrollable state refers to a state in which the torque applied to the steering axle 320 from the road surface via the wheel 100 exceeds the maximum torque of the steering motor 310. When an impact is transmitted from the road surface, the acceleration sensor 600 detects the impact value applied to the vehicle. When the acceleration sensor 600 receives an impact equal to or greater than a predetermined value, the steering angle sensor 330 is configured to detect whether the steering angle input to the steering input unit 200 matches the rotation angle of the steering motor 310. When the vehicle is in a driver-uncontrollable state, the steering angle input to the steering input unit 200 may not match the rotation angle of the steering motor 310. When the driver is in a state where control is not possible, the control unit 500 controls the tilt brake device 420 so that the tilt brake disc 420a as the tilt brake device 420 is released from the tilt brake caliper 420b and the tilt unit housing 410 rotates.

[0046] The tilting unit housing 410 can tilt around the tilting yoke 340 based on a tilting signal from the control unit 500. Preferably, when the tilting signal from the control unit 500 is transmitted to the tilting brake caliper 420b, the tilting unit housing 410 shown in FIG. 5 rotates clockwise around the tilting shaft 450 inserted into the tilting yoke 340. When the tilting unit housing 410 tilts around the tilting shaft 450 of the tilting yoke 340, the tilting shock absorber 440 is compressed. In a driver-uncontrollable state, the suspension shock absorber primarily absorbs vertical impacts. The tilting shock absorber 440 further absorbs any impacts that the suspension shock absorber cannot absorb, and the wheel 100 moves rearward and upward around the tilting shaft 450.

[0047] While a suspension shock absorber absorbs impacts by moving up and down and is unable to absorb impacts in the forward and backward directions, which can damage the wheel 100, the tilting unit 400 moves upward as the wheel 100 moves backward, effectively absorbing impacts while overcoming obstacles and preventing internal damage to the in-wheel motor unit 700. When the impact is resolved by the tilting shock absorber 440, the driver can escape from an uncontrollable state. When the driver escapes from an uncontrollable state, the tilting unit housing 410 is configured to restore itself by the elastic restoring force of the tilting shock absorber 440. Preferably, the tilting unit housing 410 is restored by rotating counterclockwise with reference to FIG. 5.

[0048] The tilt brake disc 420a is fixed when the tilting unit housing 410 is released from the tilting yoke 340. Preferably, when the tilt angle detected by the tilt angle sensor is 0 degrees, the control unit 500 controls the tilt brake disc 420a to be fixed.

[0049] 6 is a flowchart of a steering shock absorption method for an in-wheel motor according to an embodiment of the present invention. Referring to FIG. 6, the steering shock absorption method for an in-wheel motor according to an embodiment of the present invention includes a step (S100) in which an acceleration sensor 600 detects whether a predetermined impact value or more has been applied, a step (S200) in which a control unit 500 determines whether a driver control state is possible when the acceleration sensor 600 detects that a predetermined impact value or more has been applied, a step (S300) in which the tilt brake disc 420a is released, a step (S400) in which the tilt angle sensor 430 detects whether the tilt portion housing 410 has tilted within a predetermined tilt limit angle, and a step (S500) in which the tilt angle sensor 430 detects whether the tilt portion housing 410 has tilted within the predetermined tilt limit angle. When it is detected that the tilting unit housing 410 has been tilted within the predetermined time, the control unit 500 adjusts the steering angle input to the steering input unit 200 and the rotation angle of the steering motor 310 so that they coincide with each other (S500), with the tilting brake disc 420a released; when the control unit 500 has completed the adjustment so that the steering angle input to the steering input unit 200 and the rotation angle of the steering motor 310 coincide with each other (S600), the tilting angle sensor 430 detects whether the tilting unit housing 410 has been restored; and when the tilting angle sensor 430 detects that the tilting unit housing 410 has been restored, the tilting brake disc 420a is fixed (S700).

[0050] If acceleration sensor 600 detects that an impact of a predetermined value or greater has been applied in step S100, tilt unit 400 is selectively driven. In one embodiment, the predetermined impact value is 2.5 G. If an impact of 2.5 G or greater is applied to acceleration sensor 600, control unit 500 determines whether a driver-controllable state is present (S200). In step S200, control unit 500 determines whether a torque applied from the road surface to steering axle 320 via wheel 100 exceeds a maximum torque of steering motor 310. If the torque applied from the road surface to steering axle 320 via wheel 100 exceeds the maximum torque of steering motor 310, the angle of the steering wheel operated by the driver and the angle of steering axle 320 may not correspond to each other. At this time, the control unit 500 instantaneously calculates the magnitude of the impact from the road surface using signals sensed by the acceleration sensor 600, the steering angle sensor 330, and the steering wheel angle sensor. If the control unit 500 determines that the driver is unable to control the vehicle (S200), the control unit 500 releases the tilting brake disc 420a (S300).

[0051] When the tilt brake disc 420a is released (S300), the tilt unit housing 410 tilts by a predetermined angle. In step S400, the tilt angle sensor 430 detects whether the tilt unit housing 410 has tilted within a predetermined tilt limit angle, and the tilt brake caliper 420b remains out of contact with the tilt brake disc 420a. Thereafter, if the tilt angle sensor 430 detects that the tilt unit housing 410 has tilted within the predetermined tilt limit angle in step S400, the control unit 500 adjusts the steering angle input to the steering input unit 200 to match the rotation angle of the steering motor 310 (S500).

[0052] In the state where the tilt brake disc 420a is released (S300), the control unit 500 adjusts the steering angle input to the steering input unit 200 so that it matches the rotation angle of the steering motor 310 (S500), which is a step of adjusting the angle of the steering motor 310 according to the steering angle input to the steering input unit 200. The control unit 500 adjusts the rotation angle of the steering motor 310 so that it matches the steering angle input to the steering input unit 200. When the control unit 500 completes the adjustment in the step (S500) of adjusting the steering angle input to the steering input unit 200 so that it matches the rotation angle of the steering motor 310, the control unit 500 includes a step (S600) in which the tilt angle sensor detects whether the tilt unit housing has been restored. In step S600, the tilt angle sensor 430 detects whether the tilting unit housing 410 has been restored, and if the tilt angle of the tilting unit housing 410 becomes 0 degrees, it detects that the tilting unit housing 410 has been restored. If the tilt angle sensor 430 detects that the tilting unit housing 410 has been restored, the control unit 500 controls the tilting brake disc 420a to be fixed (S700).

[0053] If the tilt angle sensor 430 detects that the tilting unit housing 410 has been restored in step S600, the method includes a step S700 of fixing the tilting brake disc 420a. In step S700 of fixing the tilting brake disc 420a, the tilting brake caliper 420b can be fixed so that it contacts the tilting brake disc 420a. More preferably, if the control unit 500 transmits a fixing signal to the tilting brake caliper 420b, the tilting brake caliper 420b grips and fixes both sides of the tilting brake disc 420a.

[0054] 7 is a flowchart illustrating a driver-controllable state of a method for absorbing steering shock for an in-wheel motor according to an embodiment of the present invention. Referring to FIG. 7, in the step (S200) of determining whether the driver-controllable state is present, the control unit 500 determines whether the rotation angle of the steering motor is equal to the input steering angle (S210). If the steering angle and the rotation angle are not equal, the control unit 500 determines whether the current torque applied from the steering motor is equal to or less than a predetermined steering motor limit torque (S220). If the current torque applied from the steering motor is equal to or less than the predetermined steering motor limit torque, the control unit 500 determines the driver-controllable state (S230). If the current torque applied from the steering motor exceeds the predetermined steering motor limit torque, the control unit 500 determines the driver-controllable state (S250). If the driver-controllable state is present, the control unit 500 further includes a step (S240) of adjusting the steering angle input to the steering input unit 200 so that it matches the rotation angle of the steering motor 310.

[0055] If the impact value detected by the acceleration sensor 600 is equal to or greater than a predetermined impact value, the control unit 500 determines whether the vehicle is in a driver-controllable state (S200). If the torque applied to the steering shaft 320 from the road surface via the wheel 100 is within the range of the maximum torque of the steering motor 310, the control unit 500 determines that the vehicle is in a driver-controllable state. If the control unit 500 determines that the vehicle is in a driver-controllable state, the control unit 500 adjusts the rotation angle of the steering motor 310 (S240). Specifically, the control unit 500 controls the steering angle input to the steering input unit 200 so that it matches the rotation angle of the steering motor 310. If the vehicle is in a driver-controllable state, the control unit 500 controls the tilting unit 400 to maintain a fixed state, since the steering angle intended by the driver can be maintained.

[0056] 8 is a flowchart showing a method for absorbing steering shock for an in-wheel motor according to an embodiment of the present invention when the tilt angle is outside the tilt limit angle. Referring to FIG. 8, in step S400, the tilt angle sensor 430 detects whether the tilting unit housing 410 is tilted within a predetermined tilt limit angle. If the tilting unit housing 410 detects that the tilting unit housing 410 is tilted outside the predetermined tilt limit angle, the tilt brake disc 420a is fixed in step S410. The control unit 500 adjusts the steering angle input to the steering input unit 200 so that it matches the rotation angle of the steering motor 310 in step S420. The method further includes a step (S420) of adjusting the steering angle input to the power unit 200 so that it matches the rotation angle of the steering motor 310, a step (S430) of releasing the tilt brake disc 420a when the adjustment is completed, a step (S440) of using the tilt angle sensor 430 to detect whether the tilt unit housing 410 has been restored, and a step (S450) of fixing the tilt brake disc 420a when the tilt angle sensor 430 detects that the tilt unit housing 410 has been restored.

[0057] In step S400, the tilt angle sensor 430 detects whether the tilting unit housing 410 has been tilted within a predetermined tilt limit angle. If the tilt angle sensor 430 detects that the tilting unit housing 410 has been tilted beyond the predetermined tilt limit angle, the tilt brake disc 420a is locked (S410). In one embodiment, the predetermined tilt limit angle is 45 degrees. If the tilt angle sensor 430 detects that the tilting unit housing 410 has been tilted beyond the predetermined tilt limit angle, it transmits a signal to the control unit 500. In this case, the control unit 500 transmits a lock signal to the tilt brake caliper 420b to control it to contact the tilt brake disc 420a. In other words, the tilt brake disc 420a is locked (S410).

[0058] With the tilt brake disc 420a fixed, the tilt shock absorber 440 absorbs impacts transmitted from the road surface. The control unit 500 determines whether the torque applied to the steering shaft 320 is lowered within the maximum torque range of the steering motor 310. With the tilt brake disc 420a fixed, the control unit 500 adjusts the steering angle input to the steering input unit 200 so that it matches the rotation angle of the steering motor 310 (S420). After completing the adjustment, the control unit 500 releases the fixed tilt brake disc 420a (S430). The tilt angle sensor 430 detects whether the tilt unit housing 410 has been restored (S440). In one embodiment, the control unit 500 determines that the tilt unit housing 410 has been restored when the tilt angle detected by the tilt angle sensor 430 is 0 degrees. If it is determined that the tilting portion housing 410 has been restored, the control portion 500 controls the tilting brake disc 420a to be fixed (S450).

[0059] In summary, the present invention provides a steering shock absorbing structure for an in-wheel motor that can minimize damage to the in-wheel motor by secondarily absorbing shocks above a predetermined limit by applying a new tilt unit 400. Also, the present invention provides a steering shock absorbing method for an in-wheel motor that can selectively drive the tilt unit 400 by calculating the amount of shock detected by multiple sensors.

[0060] The above content describes the preferred embodiment of the present invention, and the present invention has various different combinations. The above-described embodiment describes the best mode of the present invention, and various modifications are possible. [Explanation of symbols]

[0061] 100 wheels 200 Steering input unit 300 Steering Unit 301 Lower arm 302 Knuckle 310 Steering motor 320 Steering shaft 330 Steering angle sensor 340 tilting yoke 400 tilting unit 410 Tilting section housing 420 Tilt braking device 420a tilting brake disc 420b tilting brake caliper 430 Tilt Angle Sensor 440 tilting shock absorber 450 Tilt axis 500 control section 600 Accelerometer 700 In-wheel motor section

Claims

1. An in-wheel motor provided in a wheel; a steering input unit that detects the steering angle of the steering wheel; a steering unit fastened to the steering input portion and configured to steer the wheels in accordance with a steering angle of the steering input portion; a tilting unit having one end connected to the steering unit and the other end connected to the wheel, the tilting unit being configured to be tilted relative to the steering unit; a control unit that selectively drives the tilt unit.

2. The steering unit is a steering motor coupled to the steering input and configured to rotate the tilt unit; 2. The steering shock absorbing structure for an in-wheel motor according to claim 1, further comprising: a steering angle sensor connected to the steering motor based on a steering shaft and configured to detect whether a steering angle input to the steering input unit matches a rotation angle of the steering motor.

3. The tilting unit is a tilt yoke having one end fastened to the steering unit; a tilting unit housing disposed adjacent to the wheel and configured to be rotatably tilted about a tilting axis located on the other side of the tilting yoke; a tilt braking device positioned between the tilting portion housing and the tilting yoke, for selectively fixing the tilting portion housing; a tilt shock absorber configured to have one end connected to the tilt yoke and the other end connected to the tilt portion housing; 3. The steering shock absorbing structure for an in-wheel motor according to claim 2, further comprising a tilt angle sensor coupled to the tilt braking device and configured to detect the tilt angle of the tilting portion housing.

4. Further, an acceleration sensor for detecting an impact value of the vehicle is included.

4. The steering shock absorbing structure for an in-wheel motor according to claim 3, wherein the steering angle sensor is configured to detect whether a steering angle input to the steering input unit matches a rotation angle of the steering motor when an impact equal to or greater than a predetermined value is applied to the acceleration sensor.

5. 5. The steering shock absorbing structure for an in-wheel motor according to claim 4, wherein the control unit controls the tilt braking device to fix the tilt portion housing when the vehicle is in a driver-controllable state.

6. 5. The steering shock absorbing structure for an in-wheel motor according to claim 4, wherein the control unit controls the tilt braking device to release the fixation of the tilt portion housing when the vehicle is in a state where the driver cannot control it.

7. 7. The steering shock absorbing structure for an in-wheel motor according to claim 6, wherein the tilting portion housing is configured to be tilted based on the tilting yoke, and the tilting shock absorber is compressed.

8. When the driver is no longer in a controllable state, 8. The steering shock absorbing structure for an in-wheel motor according to claim 7, wherein the tilting portion housing is restored to its original state by an elastic restoring force of the tilting shock absorber.

9. 9. The steering shock absorbing structure for an in-wheel motor according to claim 8, wherein the tilting portion housing is configured to be released from tilting with respect to the tilting yoke, and the tilt braking device is configured to be fixed.

10. 2. The steering shock absorbing structure for an in-wheel motor according to claim 1, further comprising an in-wheel motor unit connected to the tilt unit and applying a driving force to the wheel independently.

11. a step in which an acceleration sensor detects whether or not an impact equal to or greater than a predetermined value has been applied; a step of determining whether or not the control unit is in a driver controllable state when an impact equal to or greater than the predetermined value is applied; When the control unit determines that the vehicle is in a driver-controllable state, the tilt braking device is released. a tilt angle sensor detecting whether the tilting unit housing is tilted within a predetermined tilt limit angle; a step in which, when the tilting unit housing is tilted within a predetermined tilt limit angle, the control unit adjusts the steering angle input to the steering input unit and the rotation angle of the steering motor so that they coincide with each other in a state in which the tilting braking device is released; When the control unit completes the adjustment so that the steering angle input to the steering input unit and the rotation angle of the steering motor are equal, the tilt angle sensor detects whether the tilt unit housing is restored; and locking the tilt braking device when the tilt angle sensor detects that the tilting portion housing has been restored.

12. In the step of determining whether the control unit is in a driver controllable state, a step of determining whether or not the rotation angle of the steering motor corresponding to the input steering angle is the same; If the steering angle and the rotation angle are not equal, determining whether a current torque applied from the steering motor is equal to or less than a predetermined limit torque of the steering motor; 12. The steering shock absorbing method for an in-wheel motor according to claim 11, further comprising: determining that the state is controllable by the driver when the current torque applied from the steering motor is equal to or less than a predetermined limit torque of the steering motor; and determining that the state is uncontrollable by the driver when the current torque applied from the steering motor exceeds the predetermined limit torque of the steering motor.

13. 13. The steering shock absorbing method for an in-wheel motor according to claim 12, further comprising the step of: adjusting the steering angle input to the steering input unit so that it coincides with the rotation angle of the steering motor, in the step of determining that the control unit is in a driver-controllable state.

14. In the step of detecting whether the tilt angle is within a predetermined tilt limit angle, locking the tilt braking device when the tilting portion housing is tilted beyond a predetermined tilt limit angle; a step of adjusting the steering angle input to the steering input unit and the rotation angle of the steering motor so that they coincide with each other by the control unit; a step of releasing the lock of the tilt braking device when the adjustment is completed so that the steering angle input to the steering input unit and the rotation angle of the steering motor coincide with each other; The tilt angle sensor detects whether the tilt unit housing is restored; The steering shock absorbing method for an in-wheel motor according to claim 11, further comprising: fixing the tilt braking device when the tilting portion housing is restored.

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