JP2006201116A - Hub unit with sensor for vehicle with power steering, and sensor system for the vehicle with power steering - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pair of hub units with sensors for a vehicle mounted with a power steering capable of sharing a sensor with a torque sensor for detecting the steering assistance power and a displacement sensor for detecting the grounding load of a tire, without reducing the rigidity of the steering shaft. <P>SOLUTION: The pair of hub units with sensors are provided with each of sensors Sti, Sto, Sbi, and Sbo in the inside and on the outside of the axial direction of the left and right hub units 1 of the front wheels of the car mounted with power steering, and a processing means 10 for processing the output of each of sensors Sti, Sto, Sbi and Sbo, and a processing means is provided with the assistance power operation part 32 for obtaining the steering assistance power to a steering driver from each of the sensors Sti, Sto, Sbi and Sbo. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a sensor-equipped hub unit and a sensor device for an automobile equipped with a power steering device.

  As shown in FIG. 5, the power steering device for an automobile includes a steering shaft 102 whose one end is fixed to a handle (steering wheel) 101 as an operation means for turning left and right wheels 100, and other steering shafts 102. A rack and pinion mechanism 103 provided between the end and the left and right wheels 100, a torque sensor 104 that detects a steering torque applied to the steering shaft 102 by the operation of the handle 101, and a driver's operation by a steering operation (steering operation) Electric motor 105 that generates a steering assist force for reducing the load (steering force), a reduction gear 106 that transmits the steering assist force generated by the motor 105 to the steering shaft 102, and supply of power from an in-vehicle battery 107 In response to the sensor signals from the torque sensor 104 and the vehicle speed sensor 108 to control the driving of the motor 105. And an electronic control unit (ECU) (109) (Patent Document 1). The torque sensor 104 is attached to a torsion bar formed so as to be easily twisted so that the steering torque can be easily detected.

On the other hand, since various kinds of information are necessary for the control in the automobile, the fixed side track member fixed to the vehicle body side, the rotation side track member to which the wheel is attached, and the two members are arranged. It has also been proposed to provide a sensor device in a rolling bearing (hub unit) having two rows of rolling elements. For example, Patent Document 2 discloses a sensor-equipped hub unit in which a displacement sensor is provided on a fixed-side track member to determine the direction and magnitude of a tire ground contact load applied to the hub unit.
JP 2004-216951 A Japanese Patent Laid-Open No. 2004-3918

  According to the power steering-equipped vehicle sensor device of Patent Document 1 described above, the torque sensor is attached to a torsion bar that is easily twisted. This causes a reduction in the rigidity of the steering shaft and causes deterioration in steering feeling. There was a problem of becoming.

  Further, the steering torque detection torque sensor in Patent Document 1 and the tire contact load detection displacement sensor in the sensor-equipped hub unit of Patent Document 2 have been treated as separate sensor devices.

  It is an object of the present invention to detect a steering assist force without reducing the rigidity of a steering shaft, and to share a steering torque detection torque sensor and a tire contact load detection displacement sensor for power steering. It is an object of the present invention to provide a hub unit with a power steering-equipped vehicle sensor and a power steering-equipped vehicle sensor device capable of omitting a torque sensor.

  A hub unit with a sensor for a vehicle equipped with a power steering according to the present invention includes a vehicle body side track member fixed to the vehicle body side, a wheel side track member having a wheel mounting flange portion, and a rolling element disposed between both track members. A hub unit with a sensor in which a sensor is provided in a hub unit that is attached to a vehicle equipped with a power steering, wherein the sensor device includes sensors provided on the inner side and the outer side in the axial direction of the hub unit, and outputs of the sensors. And a processing means for processing. The processing means includes a steering assist force calculation unit that obtains a steering assist force for a driver's steering operation from the output of each sensor. .

  In addition, the power steering vehicle sensor device according to the present invention includes sensors provided on the inner and outer sides in the axial direction of the left and right hub units of the front wheels of the power steering vehicle, and processing means for processing the output of each sensor. The processing means includes a steering assist force calculation unit that obtains a steering assist force for the driver's steering operation from the output of each sensor.

  The power steering device may be a hydraulic type that generates hydraulic pressure by the rotation of the engine and applies this hydraulic pressure to the steering mechanism, and also provides the necessary assisting force to the steering mechanism by driving the electric motor. An electric type may be used. Specifically, the sensor device of the present invention is applied to an automobile equipped with a power steering such as a column type electric power steering, a rack coaxial type electric power steering, a step orifice type electronic control type power steering, an electric pump type hydraulic power steering, etc. be able to.

  The hub unit has a fixed-side track member, a rotation-side track member, and a rolling element, and the sensor is provided on the fixed-side track member.

  When the steering operation is performed, the left and right wheels turn (rotate about the vertical axis), and accordingly, a moment acts on the hub unit. This moment increases the load on the inner side of the outer hub unit in the axial direction and decreases the load on the outer side of the hub unit. Therefore, the moment acting on the wheel is obtained by detecting changes in these loads with an appropriate sensor. be able to. Since the wheel moment corresponds to the steering force, the steering force to be applied by the driver is reduced by applying a steering assist force to the steering mechanism in accordance with the magnitude of the wheel moment.

  The sensor is, for example, an ultrasonic sensor that detects, as an echo ratio, a force acting between the rolling element and the fixed-side track member, but is not limited to this, and from the rolling element to the fixed-side track member. It may be an MI sensor (magnetic impedance sensor) that detects the amount of strain due to an acting force, or may be another load sensor (including a stress sensor and a strain sensor).

  A total of four sensors are required for each of the left and right hub units, two inside and two outside. These sensors are preferably arranged at the top or bottom of the hub unit.

  If it is only to detect the steering assist force for power steering, the number of sensors may be four in total, two for each of the left and right hub units. Are preferably provided at at least three locations at predetermined intervals in the circumferential direction. Corresponding to this, the processing means corresponds to the vertical component and the longitudinal component of the load acting on the rolling bearing from the output of each sensor. Further, it is preferable to further include a tire ground load three-direction calculation unit for obtaining a left-right direction component. In this case, the number of sensors is at least 6 (one pair of inside and outside and three places) for each left and right hub unit of the front wheel. These sensors are also provided in the left and right hub units of the rear wheels.

  In this way, it is possible to determine each component of the tire ground contact load at each wheel, and by determining the steering assist force for power steering by the sensor for determining each component of the tire ground load, Compared to the conventional one that separately detects the steering torque, a sensor for detecting the power steering torque can be omitted, and the cost can be greatly reduced.

  According to the hub unit with a sensor for a power steering vehicle according to the present invention, the steering assist force can be detected without reducing the rigidity of the steering shaft by attaching the hub unit to the front wheel of the power steering vehicle. In addition, a sensor that detects the power steering torque can be omitted by adopting a configuration that can be used as a sensor device that determines the ground load of the tire.

  According to the power steering vehicle-equipped sensor device of the present invention, the steering assist force can be detected without reducing the rigidity of the steering shaft by providing the power steering vehicle-equipped vehicle sensor device. In addition, a sensor that detects the power steering torque can be omitted by adopting a configuration that can be used as a sensor device that determines the ground load of the tire.

  Embodiments of the present invention will be described below with reference to the drawings. In the following description, the left and right refer to the left and right in FIG. Note that the left is inside the vehicle and the right is outside the vehicle.

  FIG. 1 shows one embodiment of a hub unit with a sensor for a power steering vehicle according to the present invention, and FIG. 4 shows one embodiment of a sensor device for a power steering vehicle with the present invention.

  The hub unit (1) is arranged in two rows between the fixed side track member (3) fixed to the vehicle body side, the rotary side track member (4) to which the wheel is attached, and both members (3) and (4). A ball (5), which is a plurality of rolling elements, and a cage (6) for holding each row of balls (5) are provided.

  The fixed-side raceway member (3) has a bearing outer ring (fixed ring) function, and includes a cylindrical portion (12) in which two rows of outer ring raceways are formed on the inner peripheral surface, and a cylindrical portion (12 ) And a flange portion (13) attached to the suspension device (vehicle body side portion) with a bolt.

  The rotation side raceway member (4) has a large diameter portion (15) having a first raceway groove (15a) and a small diameter portion (16) having an outer diameter smaller than the diameter of the first raceway groove (15a). The inner ring (14), and the inner ring (14), the inner ring (14), which has a small diameter part (16) and is fitted to the outer diameter, and the right side is in close contact with the left side of the large diameter part (15) of the inner axis (14) (17) Near the right end of the inner shaft (14), a flange portion (18) to which a plurality of bolts (19) for attaching a wheel is fixed is provided. A raceway groove (17a) is formed in the right part of the inner ring (17) so as to be parallel to the raceway groove (15a) of the inner shaft (14), and a shoulder part (17b ) Is formed. A sealing device (20) is provided between the right end portion of the fixed-side track member (3) and the inner shaft (14). A male screw is provided at the left end of the small diameter portion (16) of the inner shaft (14), and the inner ring (17) is connected to the inner shaft (14) by a nut (21) screwed to the male screw. It is fixed to. A cover (22) is covered with the left end portion of the fixed race member (3).

  The hub unit (1) has an ultrasonic sensor (Sti) that detects the force (hereinafter referred to as the “rolling element load”) acting between the fixed raceway member (3) and the ball (5) in the inner row. Sbi) and ultrasonic sensors (Sto) (Sbo) for detecting the rolling element load of the balls (5) in the outer row are provided.

  The power steering vehicle sensor device (2) includes an ultrasonic sensor (Sti) (Sbi) (Sto) (Sbo) provided in each hub unit (1), and these ultrasonic sensors (Sti) (Sto). And processing means (10) (see FIG. 4) for processing the outputs of (Sbi) and (Sbo). The ultrasonic sensors (Sti) (Sto) (Sbi) (Sbo) are provided on the front and rear as well as on the top and bottom shown in the figure (these are indicated by the symbols (Sfi) (Sfo) (Represented as (Sri) (Sro)). However, the number and arrangement of the ultrasonic sensors are not limited to this.

  The ultrasonic sensors (Sti), (Sto), (Sbi), (Sbo), (Sfi), (Sfo), (Sri), and (Sro) receive the reflected waves of the ultrasonic waves output from the transducers at the receiving unit, and FIG. The output is obtained as the echo ratio shown below.

Echo ratio = 100 × (H0−H1) / H0
H0: Echo intensity when the rolling element is separated from the ultrasonic sensor by a half pitch H1: Echo intensity when the rolling element is located directly below the ultrasonic sensor This echo ratio has the relationship shown in FIG. By using this, the rolling element load can be obtained from the echo ratio. If the load acting on the ball (5) is large, the contact area becomes large and the reflected wave becomes small. Therefore, when the rolling element load is large, a large echo ratio is output.

  As shown in FIG. 4, the processing means (10) includes all sensors (Sti) (Sto) (Sbi) (Sbo) (Sfi) (Sfo) (Sfo) (for each wheel) provided in the hub unit (1). The tire contact load 3-way component calculation unit (31) for obtaining the 3-way component of the tire contact load using the output of Sri) (Sro) and the top and bottom of the left and right hub unit (1) of the front wheel A steering assist force calculating section (32) for obtaining a steering assist force using outputs of the sensors (Sti), (Sto), (Sbi), and (Sbo) is provided. The calculation results in the calculation units (31) and (32) are sent to an electronic control unit (ECU) (33), and the calculation results in the tire ground load three-direction component calculation unit (31) are used for vehicle control. The calculation result in the steering assist force calculation unit (32) is used to control the drive of the electric motor (see FIG. 5) that generates the steering assist force for reducing the driver's load due to the steering operation. The

  The processing means (10) includes an echo ratio equation, an echo ratio obtained from each ultrasonic sensor (Sti) (Sto) (Sbi) (Sbo) (Sfi) (Sfo) (Sri) (Sro). Formulas for determining the rolling element load at the position, formulas for determining the vertical component, front / rear direction component, and left / right component of the tire ground contact load from these rolling element loads, ultrasonic sensors (Sti) (Sto) provided on the left and right of the front wheels (Sbi) The relationship between the change in rolling element load obtained from (Sbo) and the moment acting on the left and right wheels from the road surface during steering, the steering torque acting on the steering shaft from the moment acting on the left and right wheels from the road surface The required formulas are stored.

  When the driver operates the steering wheel, the left and right wheels on the front side try to turn in the operation direction. At that time, a moment acts on the wheel from the road surface. This moment increases (or decreases) the axially rolling element load and decreases (or increases) the axially outer rolling element load. Therefore, the moment acting on the wheel can be calculated by detecting the rolling element loads on the inner and outer sides in the axial direction. The magnitude of this moment corresponds to the magnitude of the driver's load caused by the steering wheel operation. Therefore, the steering assist force for reducing the driver's load caused by the steering wheel operation is obtained from this moment, and this steering auxiliary force is obtained by the electric motor. Therefore, a steering assist force can be applied to the steering mechanism of the vehicle.

  On the other hand, the ground load applied to the tire varies with changes in the speed and posture of the traveling vehicle, and the rolling element load changes according to the tire ground load variation. When multiple sensors are installed, the degree of influence on the sensor differs depending on the components of the longitudinal load, left and right load, and vertical load acting on the tire. By obtaining the corresponding echo ratio, rolling element load when left and right load is applied and the corresponding echo ratio, and rolling element load when vertical load is applied and the corresponding echo ratio, ultrasonic waves are obtained. From the echo ratio obtained by the sensors (Sti), (Sto), (Sbi), (Sbo), (Sfi), (Sfo), (Sri), and (Sro), the three-way component force of the tire contact load can be obtained.

  When sensors are installed at multiple locations and each component of the ground load is obtained separately, errors due to the effects of other components are likely to occur. (Sti) (Sto) (Sbi) (Sbo) (Sfi) (Sfo) (Sri) (Sro) are installed on the inside and outside of the top, bottom, front and rear of the fixed track member (3), respectively. By using a total of eight locations, the component force in three directions can be obtained with high accuracy, and the moment about the longitudinal axis and the moment about the vertical axis can also be obtained.

  In the above, the steering assist force is obtained using the outputs of the sensors (Sti) (Sto) (Sbi) (Sbo) provided on both the top and bottom of the left and right hub units (1) of the front wheels. However, it can also be determined using the output of one of the top and bottom sensors. Further, instead of directly calculating using the output of the sensor, it is also possible to calculate the steering assist force from the tire ground load three-direction component calculated by the tire ground load three-direction component calculation unit (31) on the left and right front wheels. .

FIG. 1 is a longitudinal sectional view showing an embodiment of a hub unit with a sensor for a vehicle equipped with a power steering according to the present invention. FIG. 2 is a diagram illustrating an example of an echo waveform obtained by the ultrasonic sensor. FIG. 3 is a graph showing the relationship between the echo ratio obtained by the ultrasonic sensor and the rolling element load. FIG. 4 is a block diagram showing an embodiment of a power steering-equipped vehicle sensor device according to the present invention. FIG. 5 is a schematic diagram showing a conventional power steering equipped vehicle to which the power steering equipped vehicle-equipped hub unit and sensor device of the present invention are applied.

Explanation of symbols

(1) Hub unit
(2) Sensor device
(3) Fixed side raceway member
(4) Rotating track member
(5) Ball (rolling element)
(Sti) (Sto) (Sbi) (Sbo) (Sfi) (Sfo) (Sri) (Sro) Ultrasonic sensor
(10) Processing means
(31) Tire contact load 3-way component calculation unit
(32) Steering assist force calculator

Claims (6)

A vehicle body side track member fixed to the vehicle body side, a wheel side track member having a wheel mounting flange portion, and a hub unit attached to a power steering equipped vehicle having a rolling element disposed between both track members. A hub unit with a sensor provided,
Sensors provided respectively on the inner side and the outer side of the hub unit in the axial direction and processing means for processing the output of each sensor are provided. The processing means uses the steering assist for the driver's steering operation from the output of each sensor. A hub unit with a sensor for a vehicle equipped with a power steering, characterized in that it has a steering assist force calculation unit for obtaining a force.   2. The hub unit with a sensor for a power steering vehicle according to claim 1, wherein the sensor is an ultrasonic sensor that is provided on the fixed-side track member and detects a force acting between the rolling element and the fixed-side track member as an echo ratio.   The sensors are provided at at least three places spaced apart in the circumferential direction of the fixed-side raceway member, and the processing means includes a vertical component, a front-rear component and a left-right component of the load acting on the rolling bearing from the output of each sensor. The hub unit with a sensor for a vehicle equipped with a power steering according to claim 1 or 2, further comprising a three-direction calculation unit for tire ground contact load for obtaining a direction component.   Sensors provided on the inner and outer sides in the axial direction of the left and right hub units of the front wheels of the vehicle equipped with a power steering system, and processing means for processing the output of each sensor are provided. A power steering-equipped vehicle sensor device comprising a steering assist force calculation unit for obtaining a steering assist force for the steering operation of the vehicle.   Each hub unit has a fixed-side raceway member, a rotary-side raceway member, and a rolling element, and a sensor is provided in the fixed-side raceway member and applies an echo ratio to the force acting between the rolling element and the fixed-side raceway member. The power steering-equipped vehicle sensor device according to claim 4, wherein the sensor device is an ultrasonic sensor that is detected as:   The sensors are provided at at least three places spaced apart in the circumferential direction of the fixed-side raceway member, and the processing means includes a vertical component, a front-rear component and a left-right component of the load acting on the rolling bearing from the output of each sensor. 6. The sensor device for a power steering vehicle according to claim 4, further comprising a tire contact load three-direction calculation unit for obtaining a direction component.

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