KR100447747B1 - steering apparatus for vehicle - Google Patents

Abstract

Steering gear of the present invention, the rack housing; A central rack bar installed in the center of the rack housing, a rack gear formed on a surface thereof, and a left cylinder and a right cylinder formed at both ends thereof; A pinion engaged with the rack gear of the central rack bar and connected to a steering wheel; A left rack bar having one end connected to a left tie rod and having a piston formed at the other end inserted into the left cylinder; One end is connected to the right tie rod, and a piston formed at the other end includes a right rack bar inserted into the right cylinder.

Description

Steering apparatus for vehicle

The present invention relates to a vehicle steering apparatus.

The steering apparatus mounted on the vehicle is a mechanism that transmits the rotational movement of the steering wheel (handle) to the tire so that the vehicle can turn.

Such a steering device is composed of a steering wheel, a link mechanism, a steering gear, a tie rod, a knuckle, and the like.

The link mechanism is a device that transmits the rotational movement of the steering wheel to the steering gear.

A steering gear commonly applied to a passenger car is a rack-and-pinion type as shown in FIG. 1, which reduces the rotational motion of the steering wheel and converts the rotational motion into a linear motion.

That is, the pinion connected to the link mechanism and the rack bar formed with the rack gear to be engaged with the pinion are engaged to convert the rotational motion of the pinion into linear motion.

Since the tie rods are connected to both ends of the rack bar through the ball joint, and the tie rods are connected to the knuckles of the suspension system by ball joints, when the rack bar moves to the left side, the left and right tie rods connected to the rack bar are The left and right knuckles will turn left and the vehicle will turn.

As a general performance required for the steering device as described above, the steering operation should not be affected by the impact while driving, easy to operate, smooth change of direction, small turning radius, easy to change direction, the direction of travel When changing, there should be no excessive force applied to the chassis and body parts, the steering wheel will be safe even at high speeds, the steering wheel's rotation and wheel turning will not be big.

However, in the conventional rack and pinion steering gear, since left and right tie rods are connected by one rack bar, the left tire and the right tire rotate in a constant relationship. That is, the conventional method has a problem that it is not possible to arbitrarily give the turning angle of the left tire and the right tire.

In particular, in the case of rotating the vehicle at low speed, the turning center of the vehicle needs to be on the extension line of the rear axle center line so that each tire does not cause side slip, and the turning center of the left and right front axle tires must match that point. do.

For this purpose, it is necessary to increase the rotation angle of the turning inner tire rather than the turning outer tire in the front axle.

However, the conventional rack and pinion method has a problem that it is difficult to match the center of rotation of the left and right front axle tires because of the structure consisting of the left tie rod, the rack bar and the right tie rod. As described above, when the turning centers of the left and right front axle tires do not coincide with each other, various problems such as wear of the tire and deterioration of turning stability occur.

In addition, when the vehicle rotates at high speed, there is a problem in that the turning inner tire and the turning right tire cannot be individually controlled according to the driving state of the vehicle. That is, when the steering wheel is excessively rotated by the driver's mistake while the vehicle is traveling at high speed, in the related art, since the rotational movement of the steering wheel is transmitted as it is to the tire through the steering gear, the vehicle is driven by excessive steering during high-speed driving. There is a problem of overturning.

In addition, when the vehicle rotates due to the fine rotation of the steering wheel while the vehicle is running at high speed, in the prior art, even though it is necessary to finely adjust the rotation amount of the left and right tires according to the driving state, There was a problem that the amount of rotation of the right tire can not be adjusted individually.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a steering apparatus and a steering gear that can separately adjust the movement amount of the rack bars on the left and right sides by separating the rack bars of the vehicle steering gear from side to side.

1 is an exploded perspective view showing a conventional rack and pinion steering gear

2 is a block diagram and a cross-sectional view showing a steering gear of the present invention steering apparatus.

3 is a block diagram of the present invention

<Explanation of symbols for the main parts of the drawings>

M: auxiliary motor

30: rack housing

100A: Left rack bar 100B: Right rack bar

101: center rack bar 101C: rack gear

101A: left cylinder 101B: right cylinder

102A: Left piston 102B: Right piston

P: Pinion P1: Aux Pinion

SV1: Left direction switching valve SV2: Right direction switching valve

ECU: control unit

A vehicle steering apparatus according to the present invention for achieving the above object includes a plurality of sensors for detecting a driving state of the vehicle; A control unit which receives a value detected by the sensor; A steering gear controlled by the control unit and driven by a pinion connected to a steering wheel; The steering gear is; Rack housing; A central rack bar installed inside the center of the rack housing, having a rack gear formed on a surface thereof, and having a left cylinder and a right cylinder configured to receive oil at both ends thereof; A left rack bar having one end connected to a left tie rod and having a piston formed at the other end inserted into the left cylinder; A right rack bar having one end connected to a right tie rod and having a piston formed at the other end inserted into the right cylinder; A left direction switching valve connected to the left cylinder and driven by the controller; A right direction switching valve connected to the right cylinder and driven by the controller; It is configured to include a pump connected to the left cylinder and the right cylinder.

With the above configuration, the control unit that receives the driving information of the vehicle can optimally control the movement amount of the left rack bar and the right rack bar according to the driving state of the vehicle.

In addition, the steering apparatus of the present invention includes an auxiliary pinion engaged with the rack gear of the central rack bar, and an auxiliary motor connected to the auxiliary pinion and driven by the controller.

With the above configuration, even if adjustment of the left rack bar and the right rack bar is impossible due to the failure of the pump, it is possible to assist steering of the steering wheel by the auxiliary motor.

In addition, the steering gear of the present invention, the rack housing; A central rack bar installed inside the center of the rack housing, having a rack gear formed on a surface thereof, and having a left cylinder and a right cylinder configured to receive oil at both ends thereof; A pinion engaged with the rack gear of the central rack bar and connected to a steering wheel; A left rack bar having one end connected to a left tie rod and having a piston formed at the other end inserted into the left cylinder; One end is connected to the right tie rod, and a piston formed at the other end includes a right rack bar inserted into the right cylinder.

By the above configuration, since the vibration transmitted from the road surface to the left rack bar and the right rack bar is attenuated in the left cylinder and the right cylinder, the road surface vibration is not transmitted to the steering wheel.

Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings.

FIG. 2 is a cross-sectional view of the steering gear of the present invention and a configuration of the steering device of the present invention, and FIG. 3 is a block diagram of the steering device of the present invention.

As shown in FIG. 2, the steering gear of the present invention includes a rack housing 30 and a central rack bar 101 inserted into the rack housing 30.

A rack gear 101C is formed on the surface of the center rack bar 101, and a pinion PN connected by a link to a steering wheel (not shown) is engaged with the rack gear 101C. The structure from the steering wheel to the pinion PN is the same as in the prior art.

At both ends of the center rack bar 101, left cylinder 101A and right cylinder 101B for accommodating oil are formed.

One end of the left rack bar (100A) is connected to the left tie rod (not shown) by a ball joint, the other end is formed with a left piston (102A). The left piston 102A is inserted into the left cylinder 101A formed in the center rack bar 101.

One end of the right rack bar (100B) is connected to the right tie rod (not shown) by a ball joint, the other end is formed a right piston (102B). The right piston 102B is inserted into the right cylinder 101B formed in the center rack bar 101.

The vehicle steering apparatus of the present invention includes all of the above configuration of the steering gear, but not including a steering wheel (not shown), a control unit and various sensors.

However, a port is formed in the left cylinder 101A and the right cylinder 101B of the steering gear of the present invention to connect the left direction switching valve SV1 and the right direction switching valve SV2 to the upper port. The left direction switching valve SV1 and the right direction switching valve SV2 are connected to the pump P and the reservoir tank RSV as shown in FIG. 2. That is, both of the left piston 102A and the right piston 102B are connected to the pump P through the left direction switching valve SV1 and the right direction switching valve SV2 to form a hydraulic circuit.

While the left direction switching valve SV1 does not operate, the left direction switching valve SV1 is closed so that flow paths formed on both sides of the left piston 102A are not connected to the pump. That is, it is a normally closed valve in which a flow path is always closed in the state in which a control part does not operate. When the left direction switching valve SV1 is moved to the left or the right under the control of the controller, the oil pressurized by the pump P is introduced into the left or the right of the left piston 102A.

The right turn valve SV1 also works in the same way as the left turn valve SV1.

The auxiliary motor M1 may be installed in the rack housing 30, and the auxiliary pinion PN1 may be integrally formed on the rotation shaft of the auxiliary motor M1 so that the auxiliary pinion PN1 and the rack gear 101C may be engaged with each other. have.

When driving the auxiliary motor M1 by detecting the rotation of the steering wheel by the control unit ECU, the control unit acts as an electric power steering assisting the steering force of the steering wheel.

In addition, the steering wheel (not shown) of the steering apparatus of the present invention is provided with a steering angle sensor (SWAS) for detecting the rotation angle of the steering wheel, the rotation angle value detected by the steering angle sensor (SWAS) control unit (ECU) Is entered.

A yaw rate sensor (YRS) for detecting yaw rate, which is a rotational angular velocity about the center of the vehicle's vertical axis, and a lateral acceleration sensor (LAS) for detecting lateral acceleration of the vehicle, are installed at a suitable place of the vehicle. ) And the values detected by the lateral acceleration sensor LAS are input to the control unit ECU.

The rotation speed value of the vehicle tire or the driving speed value of the vehicle detected by the wheel speed sensor WSP is also input to the control unit ECU.

When the steering wheel is rotated, a steering torque sensor (STS) for detecting the torque value detected by the driver may be installed between the steering wheel and the pinion (PN), and the vehicle speed sensor (VS) for detecting the driving speed of the vehicle is also a vehicle. It is installed in the right place.

That is, the control unit ECU receiving the values measured by the various sensors drives the left direction switching valve SV1, the right direction switching valve SV, the pump P, and the auxiliary motor M1 according to the driving state. The entire steering system is controlled.

Hereinafter, the operation of the present invention will be described.

First, the steering gear of the present invention can be used without being connected to the left direction switching valve SV1, the right direction switching valve SV2 and the pump P. In this case, no port is formed in the left cylinder 101A and the right cylinder 101B of the steering gear.

When the driver rotates the steering wheel, the pinion PN connected to the steering wheel rotates so that the center rack bar 101 linearly moves to the left or the right. The left cylinder 101A and the right cylinder 101B, which are filled with oil, are formed at both ends of the center rack bar 101, and the left piston 102A and the right piston are formed inside the left cylinder 101A and the right cylinder 101B. Since 102B is provided, the left rack bar 100A and the right rack bar 100B move to the left or the right side as the center rack bar 101 moves.

Since the left rack bar 100A and the right rack bar 100B are connected to the left tie rod and the right tie rod, the tire is pivoted to allow steering motion.

Since the vibration transmitted from the road surface to the steering gear is attenuated by the oil filled in the left cylinder 101A and the right cylinder 101B, the vibration generated by the impact of the road surface and the tire is not transmitted to the steering wheel.

The steering apparatus of the present invention applies a left direction switching valve SV1, a right direction switching valve SV2, a pump P, and a control unit ECU to the above steering gear. In this case, however, ports for forming a hydraulic circuit are formed in the left cylinder 101A and the right cylinder 101B of the steering gear.

In the usual case in which the left direction switching valve SV1 and the right direction switching valve SV2 block the flow path, the same function as the steering gear described above.

When the control unit ECU determines that the left rack bar 100A needs to be further moved to the left side in addition to the transfer distance of the center rack bar 101 moved by the pinion PN, the control unit ECU turns to the left. The valve SV1 is moved to the right.

In this case, since the left side of the left piston 102A is connected to the pump P, the left rack bar 100A is further moved to the right side. The movement distance of the left rack bar 100A is proportional to the opening time of the left direction switching valve SV1.

When it is determined that the left rack bar 100A needs to be further moved to the right side, the left direction switching valve SV1 may be moved to the left side.

The right direction switching valve SV2 can be operated in the same manner as the left direction switching valve SV1.

That is, when parking at a low speed, in order to form a turning center on the center line extending the rotating shaft of the rear tire, it is necessary to set the turning angles of the turning inner tire and the turning outer tire in front of the vehicle differently. The turning inner tire and the turning outer tire are further rotated by moving the left turning valve SV1 and the right turning valve SV2 corresponding to the turning angle required for the turning inner tire and the turning outer tire.

That is, in the present invention, since the left rack bar 100A and the right rack bar 100B are separated from each other, the turning angles of the left tire and the right tire can be adjusted individually.

In addition, the motion state of the vehicle running at a constant driving speed is detected by the yaw rate sensor (YRS), the lateral acceleration sensor (LAS), the wheel speed sensor (WSP), and the like. And it may limit the movement of the right rack bar (100B).

That is, when the steering wheel angle value at which the vehicle is overturned at a certain vehicle speed (for example, 100 km / h) or more is known by an experiment or the like, when the value detected by the steering wheel angle sensor (SWAS) is greater than or equal to the predetermined vehicle speed, the control unit In the ECU, the left motor M1 and the right motor M2 may not be driven.

Of course, when the values detected by the yaw rate sensor YRS and the lateral acceleration sensor LSA exceed a limit value, the control unit ECU does not drive the left rack bar 100A and the right rack bar 100B even if the steering wheel is rotated. Could be

In addition, when one of the inner and outer turning tires passes the frozen road such as an ice plate and spin occurs on one of the tires, the spin occurs when the wheel speed detected by the wheel speed sensor (WSP) exceeds a predetermined value. The controller may determine that the controller controls the steering motion of the vehicle by adding or subtracting the turning angle of the other tire.

In the present invention, the auxiliary motor M1 for driving the auxiliary pinion PN1 meshed with the central rack bar 101 serves as an electric power steering element for assisting an operation force for rotating the steering wheel.

That is, when the steering wheel is rotated to the left during low speed driving, if the auxiliary motor M1 is driven in the direction in which the center rack bar 101 is moved to the left, the driver may assist the operation of turning the steering wheel with light force. It is possible to operate the steering wheel on the road. In order to increase the operating force of the steering wheel during high speed driving, the auxiliary motor M1 may be driven in the opposite direction to the low speed driving.

In the present invention, since the left direction switching valve SV1 and the right direction switching valve SV2 are normally closed valves, the control unit ECU and the pump P are switched to the manual steering system even if a failure occurs. And steering is possible.

Since the steering gear of the present invention adopts the configuration of the left cylinder and the right cylinder filled with oil at both ends of the center rack bar, the vibration generated from the road surface and the tire can be absorbed by the oil to prevent the vibration from being transmitted to the steering wheel. Done.

In addition, the steering apparatus of the present invention can not only reduce the vibration transmitted to the steering wheel, but also enables steering without restraining the front left and right tires from each other so that the turning inside and outside tires can be adjusted to the ideal turning angle.

In addition, even if an excessive steering angle is input to the steering wheel, the left rack bar and the right rack bar can be adjusted according to the vehicle driving state.

In addition, when one tire is located on an ice road and spin occurs, the turning angle of the other tire can be arbitrarily adjusted, thereby improving turning performance.

In addition, in the present invention, since the left direction switching valve and the right direction switching valve are normally closed valves, steering is possible even when a failure occurs in the pump or the control unit.

Further, the auxiliary motor of the present invention can act as an electric power steering element that assists the driver's operating force when operating the steering wheel.

Claims (3)

A plurality of sensors for detecting a driving state of the vehicle; A control unit which receives a value detected by the sensor; A steering gear controlled by the control unit and driven by a pinion connected to a steering wheel; The steering gear is; Rack housing; A central rack bar installed inside the center of the rack housing, having a rack gear formed on a surface thereof, and having a left cylinder and a right cylinder configured to receive oil at both ends thereof; A left rack bar having one end connected to a left tie rod and having a piston formed at the other end inserted into the left cylinder; A right rack bar having one end connected to a right tie rod and having a piston formed at the other end inserted into the right cylinder; A left direction switching valve connected to the left cylinder and driven by the controller; A right direction switching valve connected to the right cylinder and driven by the controller; Vehicle steering apparatus comprising a pump connected to the left cylinder and the right cylinder. The method of claim 1, An auxiliary pinion meshing with the rack gear of the central rack bar; And an auxiliary motor connected to the auxiliary pinion and driven by the control unit. Rack housing; A central rack bar installed inside the center of the rack housing, having a rack gear formed on a surface thereof, and having a left cylinder and a right cylinder configured to receive oil at both ends thereof; A pinion engaged with the rack gear of the central rack bar and connected to a steering wheel; A left rack bar having one end connected to a left tie rod and having a piston formed at the other end inserted into the left cylinder; One end is connected to the right tie rod, the steering gear including a right rack bar is inserted into the right cylinder the piston formed on the other end.