JP2005049159A - Hub unit with sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hub unit with a sensor capable of precisely determining ground load. <P>SOLUTION: The hub unit with the sensor is provided with both a hub unit 1 and a sensor device 2. The hub unit 1 comprises a fixed-side raceway member 3, a rotating-side raceway member 4, and two rows of rotating bodies 5. The sensor device 2 comprises both a first radial-direction displacement sensor 8A supported at a support member 7 fixed to the fixed-side raceway member 3 and a second radial-direction displacement sensor 8B supported at the support member 7 at a distance of 180° from the first radial-direction displacement sensor 8A. Output signals of the displacement sensors 8A and 8B have reverse polarities. A displacement amount signal of the hub unit 1 is determined by the addition of the output of both displacement sensors 8A and 8B. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a sensor-equipped hub unit in which a hub unit constituting an automobile and a sensor device for detecting various information of the automobile are integrated.
[0002]
[Prior art]
In an automobile, various information is necessary to perform the control. Therefore, a vehicle body side member fixed to the vehicle body side, a wheel side member to which a wheel is attached, and two rows arranged between both members. It has been proposed to provide a sensor device in a hub unit having a rolling element.
[0003]
For example, Patent Document 1 discloses a sensor-equipped hub unit in which an annular support member is attached to an inner end surface of a vehicle body side member, and a strain sensor is attached to the annular support member.
[0004]
[Patent Document 1]
Japanese Patent Laid-Open No. 3-209016
[Problems to be solved by the invention]
In recent years, in addition to ABS control (anti-lock brake system), driving force control that does not spin the driving wheel when starting or accelerating, and braking force control that suppresses side slip during cornering have been implemented as a vehicle control means. However, in order to perform more accurate control, it is important to detect data that can be used effectively for these controls.
[0006]
In view of such a situation, the inventor of the present application has created a problem of accurately measuring the ground contact load of a tire to improve vehicle control.
[0007]
However, since the conventional hub unit with a sensor measures the strain of the annular support member, an error increases when the ground load is obtained from this strain, and the ground load is accurately obtained from the measured value of the strain sensor. There was a problem that could not be obtained.
[0008]
An object of the present invention is to provide a sensor-equipped hub unit that can accurately determine a ground load.
[0009]
[Means for Solving the Problems and Effects of the Invention]
A hub unit with a sensor according to the present invention includes a vehicle body side member fixed to a vehicle body side, a wheel side member to which a wheel is attached, a hub unit having two rows of rolling elements disposed between both members, and a sensor device. In the hub unit with a sensor, the sensor device is supported by the support member at a position 180 ° away from the first displacement sensor, and a first displacement sensor supported by the support member fixed to the vehicle body side member. The first displacement sensor and the second displacement sensor have opposite polarities of their output signals, and the displacement amount signal of the hub unit is obtained by adding the outputs of both displacement sensors. It is characterized by being requested | required by.
[0010]
For example, the support member is formed into an annular shape, and the inner end portion (the anti-wheel side end portion) of the vehicle body side member is fixed to the inner end portion (the anti-wheel side end portion) by press-fitting or the like, thereby forming a free end. Displacement sensors are attached to, for example, the upper end and the lower end of the end portion (wheel side end portion). The support member may be a separate member. In this case, the support member that supports the sensor is fixed to, for example, the upper end and the lower end of the vehicle body side member, respectively.
[0011]
The displacement sensor may be any of eddy current type, laser type, optical type using PSD, ultrasonic type, magnetic type, magnetostrictive type, etc. The contact type may be used instead of the non-contact type.
[0012]
The hub unit may be used on the driven wheel side of an automobile, or may be used on the driving wheel side in combination with a constant velocity joint.
[0013]
The outer end of the hub unit is displaced upward with respect to the inner end due to the load in the vertical direction (Z direction) applied to the tire (wheel), so that the inner end of the support member is positioned inside the vehicle body side member of the hub unit. This upward displacement can be detected by attaching a displacement sensor in the radial direction to the outer end of the support member so as to face the outer end (detected surface) of the vehicle body side member. The upward displacement and the vertical load of the tire are in a proportional relationship, and the ground contact load of the tire can be obtained from the obtained displacement. Further, by providing an axial displacement sensor on the same support member or another support member so that the outer end portion (detected surface) of the wheel side member faces from the axial direction, a horizontal direction (X direction or Y direction) applied to the tire is provided. The displacement corresponding to the (direction) load is obtained.
[0014]
According to the sensor-equipped hub unit of the present invention, when a load in the Z direction is applied to the tire, the detected surface at the ground side position (lower end side) moves away from the corresponding displacement sensor and 180 ° from the displacement sensor. The detected surface located at a distant position (upper end side) approaches a corresponding displacement sensor. The two displacement sensors have the same output characteristics (the change in the absolute value of the signal with respect to the displacement is the same value), and the polarity of the output signals of these displacement sensors is reversed (the output signal of the first displacement sensor increases when approaching) The displacement signal of the hub unit obtained by adding the outputs of the two displacement sensors is determined by the displacement sensor. The detection accuracy is improved as compared with the case of one. In addition, when there is a processing accuracy error on the detected surface, a signal that there is a load variation may be output depending on the distance between the displacement sensor and the detected surface due to this error. By mounting as described above, in the added signal, the amount due to the error in machining accuracy is canceled as an opposite sign, and the influence of the machining accuracy can be eliminated. Further, when a grounding load (lateral load) in the X direction is applied inward to the tire, the detected surface at the grounding side position (lower end side) approaches the displacement sensor facing this from the inside in the axial direction. The to-be-detected surface located at a position 180 ° away from the displacement sensor (on the upper end side) is separated from the displacement sensor facing this from the inside in the axial direction. The two displacement sensors have the same output characteristics (the change in the absolute value of the signal with respect to the displacement is the same value), and the polarity of the output signals of these displacement sensors is reversed (the output signal of the first displacement sensor increases when approaching) The displacement signal of the hub unit obtained by adding the outputs of the two displacement sensors is determined by the displacement sensor. The detection accuracy is improved as compared with the case of one. In addition, as the detected surface (outer end of the wheel side member) rotates, the output value of the displacement sensor may fluctuate due to rotational runout or processing accuracy, but the median value of the PP values of the output By determining the fluctuation of the rotation, it is possible to eliminate the influence of rotational runout and machining accuracy. In this way, the displacement of the hub unit is detected at a position 180 ° apart by the two displacement sensors, so that the error is small and the output is large regardless of whether the detected surface is a fixed part or a rotating part. The acting force can be detected with high accuracy.
[0015]
Each displacement sensor may be configured to measure radial displacement, and may be configured to measure both radial and axial displacement. In the former case, a vertical load (Z direction load) can be measured, and in the latter case, a horizontal load can also be measured in addition to the vertical load. Of the horizontal loads, the displacement for obtaining a lateral load (X-direction load) when the vehicle is turning is detected by providing an axial displacement sensor at the same position as the radial displacement sensor. The displacement for obtaining (Y direction load) is detected by providing an axial direction displacement sensor at a position 90 ° away from the radial direction displacement sensor. By obtaining all three loads (X direction, Y direction, and Z direction) and performing three-dimensional mapping of these loads, it is possible to detect the tire contact load in all directions.
[0016]
The tire ground contact load thus obtained is used as substitute data for the slip ratio in the ABS control, and is used in driving force control, braking force control, and the like, and can contribute to improvement in accuracy of vehicle control.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0018]
FIG. 1 shows an embodiment of a rolling hub unit with a sensor according to the present invention. In the following description, left and right and top and bottom refer to left and right and top and bottom of the drawing. Note that the left is inside the vehicle and the right is outside the vehicle.
[0019]
As shown in FIG. 1, the sensor-equipped hub unit includes a hub unit (1) and a sensor device (2) that detects a ground contact load of the tire.
[0020]
The hub unit (1) includes a fixed side track member (vehicle side member) (3) fixed to the vehicle body side, a rotation side track member (wheel side member) (4) to which wheels are attached, and both members (3) (4 ) Between the balls (5), which are a plurality of rolling elements arranged in two rows, and cages (6) for holding the balls (5) in each row.
[0021]
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) with a bolt.
[0022]
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), which is fixed to the outer diameter of the small-diameter portion (16) and the right surface is in close contact with the left-side surface of the large-diameter portion (15) of the inner shaft (14) (17). Near the right end of the inner shaft (14), there is provided a flange portion (18) to which a plurality of bolts (19) for attaching a wheel are fixed. A raceway groove (17a) is formed on 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 on the left side of the inner ring (17). ) Is formed. A sealing device (20) is provided between the right end portion of the stationary race member (3) and the inner shaft (14). A male screw portion is provided at the left end of the small diameter portion (16) of the inner shaft (14), and the inner ring (17) is fixed to the inner shaft (14) by a nut screwed to the male screw portion. ing. A cover (22) is covered with the left end portion of the fixed race member (3).
[0023]
The sensor device (2) includes an annular support member (7) attached to the fixed-side track member (3), a first radial direction displacement sensor (8A) attached to the support member (7), and a second radial direction displacement. A sensor (8B), a first axial displacement sensor (9A), a second axial displacement sensor (9B), and processing means (illustrated) for processing the outputs of the displacement sensors (8A) (8B) (9A) (9B) Abbreviation).
[0024]
The support member (7) includes a small diameter cylindrical portion (7a) concentric with the hub unit (1), a flange portion (7b) integrally formed at the right end portion of the small diameter cylindrical portion (7a), and a small diameter cylindrical portion (7a). It consists of a large diameter cylindrical part (7c) integrally formed in the right part of the outer peripheral part of a flange part (7b) so that it may become concentric.
[0025]
The support member (7) has a small-diameter cylindrical portion (7a) fixed to the inside portion of the fixed-side track member (3) by press-fitting or the like, and is outside the large-diameter cylindrical portion (7c) that is a free end. Each displacement sensor (8A) (8B) (9A) (9B) is attached to the end (wheel side end).
[0026]
The first radial direction displacement sensor (8A) is attached to the upper end position (anti-grounding side position) of the support member (7) so that the fixed-side track member (3) faces from above (radially outward). The second radial direction displacement sensor (8B) is attached to the lower end position (grounding side position) of the support member (7) so as to face the fixed side raceway member (3) from below (radially outward). . The first axial displacement sensor (9A) is mounted at the upper end position (anti-grounding side position) of the support member (7) so that the rotation side raceway member (4) faces from the left (inward in the axial direction). The second axial direction displacement sensor (9B) is located at the lower end position (grounding side position) of the support member (7) so that the rotation side raceway member (4) faces the left side (inward in the axial direction). It is installed. The first radial direction displacement sensor (8A) and the second radial direction displacement sensor (8B) have the same output characteristics (changes in the signal absolute value with respect to the displacement amount are the same value), and the first axial direction displacement sensor (9A). ) And the second axial displacement sensor (9B) have the same output characteristics. The polarities of the output signals of the first radial direction displacement sensor (8A) and the second radial direction displacement sensor (8B) are reversed (the output signal of the first radial direction displacement sensor (8A) increases when approaching). The first radial direction displacement sensor (9A) and the second axial direction displacement sensor are attached to the support member (7) so that the output signal of the second radial direction displacement sensor (8B) decreases when approaching). In both cases (9B), the polarity of the output signal is reversed (when the output signal of the first axial displacement sensor (9A) increases when approaching, the output signal of the second axial displacement sensor (9B) approaches. It is attached to the support member (7) so that it sometimes decreases. The Z direction displacement amount signal of the hub unit (1) is obtained by adding the outputs of the first radial direction displacement sensor (8A) and the second radial direction displacement sensor (8B). The X direction displacement amount signal (1) is obtained by adding the outputs of the first axial direction displacement sensor (9A) and the second axial direction displacement sensor (9B).
[0027]
2 and 3 evaluate the possibility of using displacement to monitor the tire contact load, and FIG. 2 shows the Z of the hub unit with a load in the Z direction only. FIG. 3 shows the X-direction displacement of the hub unit when the X-direction load is changed while the Z-direction load is constant.
[0028]
In FIG. 2, as shown in (a), the wheel side end (4a) of the rotation side raceway member (4) is fixed and attached to the vehicle body side end (4b) side of the member (4). A Z-direction load indicated by a hollow arrow is applied to the load-loading plate material (18), and a displacement between the load and a Z-direction displacement amount (a displacement amount at a predetermined position of the fixed-side track member (3) indicated by a solid arrow). I'm investigating the relationship. From the result shown in FIG. 2 (b), it can be seen that the Z-direction load applied to the hub unit (1) and the Z-direction displacement have a substantially linear relationship (proportional relationship), and the Z-direction load can be obtained from the Z-direction displacement. .
[0029]
Further, in FIG. 3, as shown in FIG. 3 (a), the vehicle side end (4 b) side of the member (4) with the wheel side end (4 a) of the rotation side race member (4) fixed. When the X-direction load is changed by adding the Z-direction load (constant value) indicated by the white arrow and the X-direction load indicated by the thick arrow to the load-loading plate (18) attached to the plate, this load and the X-direction are changed. The relationship with the amount of displacement (the amount of displacement of the fixed-side track member (3) relative to the rotation-side track member (4) obtained at the position indicated by the solid line arrow) is investigated. From the result shown in FIG. 3B, when the X-direction load is changed while the Z-direction load applied to the hub unit (1) is constant, the X-direction load and the X-direction displacement applied to the hub unit (1) are changed. Also, there is a substantially linear relationship, and it can be seen that the load in the X direction can be obtained from the displacement in the X direction.
[0030]
Based on these findings, the processing means of the sensor device (2) stores an arithmetic expression for obtaining the ground load from the displacement amount output as the voltage fluctuation amount. By this processing means, each displacement sensor ( The variation amount of the ground load based on the outputs of 8A), 8B, 9A, and 9B is obtained.
[0031]
FIG. 4 is a two-dimensional mapping of the sensor output change (load change) in the XZ direction. According to the above configuration, the output initial values in the X direction and the Z direction are respectively Wx0 and Wx0, as shown in FIG. As Wz0, an X direction load change amount ΔWx and a Z direction load change amount ΔWz are obtained. In the X direction, since the rotation-side raceway member (4) is a detection target, the output value may fluctuate during one rotation due to rotational shake or the like, but the fluctuation of the median P-P value of the output is obtained. By doing so, it is possible to eliminate the influence of rotational runout and the like.
[0032]
Further, although not shown, the Y-direction load is obtained by providing the third and fourth axial direction displacement sensors at a position 90 ° away from the radial direction displacement sensor, and the X-direction load, the Y-direction load, and the Z-direction load are obtained. By three-dimensional mapping, it is possible to detect the tire contact load in all directions.
[0033]
According to this sensor-equipped hub unit, when the ground contact load of the tire fluctuates, the output signals of the displacement sensors (8A), (8B), (9A), and (9B) change. (8A) is obtained from the arithmetic expression based on the correlation shown in FIG. 2 using the displacement amount signal obtained by adding the outputs of the second radial direction displacement sensor (8B) and the X direction. Regarding the load, the correlation shown in FIG. 3 is used by using the displacement signal obtained by adding the outputs of the first axial displacement sensor (9A) and the second axial displacement sensor (9B). It is obtained from an arithmetic expression based on The obtained variation amount of the ground load is output to the vehicle control means, and the vehicle is appropriately controlled.
[0034]
In the above description, only the contact load is obtained from the displacement. However, some or all of the displacement sensors (8A), (8B), (9A), and (9B) are used, and these displacement sensors (8A) ( 8B) It is also possible to obtain the rotational speed of the rotation side raceway member (4) from the number of repetitions of the output changes of (9A) and (9B). For example, when the rotation side raceway member (4) has a rotational runout and the output in the X direction shows a sine wave during one rotation, the rotation (rotation speed, number of rotations, etc.) can be detected by the frequency of the X direction output. It is.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing an embodiment of a sensor-equipped hub unit according to the present invention.
FIG. 2 is a diagram showing displacement in the Z direction of the hub unit when a load only in the Z direction is applied in the hub unit with sensor according to the present invention.
FIG. 3 is a diagram showing the X-direction displacement of the hub unit when the Z-direction load is changed and the X-direction load is changed in the hub unit with a sensor according to the present invention.
FIG. 4 is a diagram in which a sensor output change (load change) in the XZ direction is two-dimensionally mapped in the sensor-equipped hub unit according to the present invention.
[Explanation of symbols]
(1) Hub unit (2) Sensor device (3) Fixed track member (vehicle body member)
(4) Rotating side track member (wheel side member)
(5) Ball (rolling element)
(8A) 1st radial direction displacement sensor (8B) 2nd radial direction displacement sensor (9A) 1st axial direction displacement sensor (9B) 2nd axial direction displacement sensor

Claims (3)

In a sensor-equipped hub unit comprising a vehicle body side member fixed to the vehicle body side, a wheel side member to which a wheel is attached, a hub unit having two rows of rolling elements disposed between the two members, and a sensor device ,
The sensor device includes a first displacement sensor supported by a support member fixed to the vehicle body side member, and a second displacement sensor supported by the support member at a position 180 ° away from the first displacement sensor. The displacement signals of the first displacement sensor and the second displacement sensor have opposite polarities, and the displacement amount signal of the hub unit is obtained by adding the outputs of both displacement sensors. Hub unit with sensor. The hub unit with a sensor according to claim 1, wherein each displacement sensor measures a displacement in a radial direction. The hub unit with a sensor according to claim 1, wherein each displacement sensor measures displacement in both a radial direction and an axial direction.

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