JP2009103549A - Device for measuring state of quantity of rolling bearing unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve a structure enhancing a degree of freedom of arrangement of sensors 7a, 7b opposed to a face to be inspected of an encoder 4. <P>SOLUTION: An outer ring 1 is joined and fixed on a knuckle 14 in a state where an axial inner end of the outer ring 1 composing a bearing unit for supporting a wheel is internally fitted in a support hole 15 of a comparatively small diameter provided on the knuckle 14 of a suspension in an assembled state to a vehicle. In addition, a cover 5a holding a sensor holder 6a embedding each sensor 7a, 7b is internally fitted and fixed in a mounting hole 20 of a comparatively small diameter provided on the knuckle 14. The above problem is solved by adopting such a composition and making the outer diameter size of the sensor holder 6a larger than the inner diameter size of the support hole 15. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The state quantity measuring device for a rolling bearing unit according to the present invention is used for measuring a state quantity such as an external force acting between a hub constituting the rolling bearing unit and a stationary side race. Further, the obtained state quantity is used for ensuring the running stability of a vehicle such as an automobile.

  The wheel of the automobile is rotatably supported by the suspension device by a rolling bearing unit such as a double row angular type. In addition, in order to ensure the running stability of automobiles, anti-brake brake system (ABS), traction control system (TCS), and electronically controlled vehicle stability control system (ESC) etc. Is used. In order to control such various vehicle running stabilization devices, signals representing the rotational speed of the wheels, acceleration in each direction applied to the vehicle body, and the like are required. In order to perform higher-level control, it may be preferable to know the magnitude of a load (for example, one or both of a radial load and an axial load) applied to the rolling bearing unit via a wheel.

  In view of such circumstances, Patent Document 1 describes an invention in which a special encoder is used to measure the magnitude of a load applied to a rolling bearing unit. 2 to 3 are not related to the structure described in Patent Document 1, but are related to a state quantity measuring device for a rolling bearing unit that employs the same load measurement principle as the structure described in Patent Document 1. The 1st example of a structure is shown. In the first example of this conventional structure, a hub 2 that rotates together with a wheel 2 in a state where the wheel is supported and fixed at the time of use is fixed to a plurality of rolling elements on the inner diameter side of an outer ring 1 that is a stationary raceway that does not rotate even when used. 3 and 3 are rotatably supported. A preload is applied to each of the rolling elements 3 and 3 together with contact angles opposite to each other. In the illustrated example, a ball is used as the rolling element 3, but in the case of an automobile bearing unit that is heavy, a tapered roller may be used instead of the ball.

  The inner end of the hub 2 in the axial direction ("inside" in the axial direction means the center side in the width direction of the vehicle in the assembled state in the automobile, and the right side of each figure. On the contrary, in the assembled state in the automobile. The left side of each figure on the outer side in the width direction of the vehicle is referred to as “outside” in the axial direction. The same applies to the entire specification.) The cylindrical encoder 4 is supported and fixed concentrically with the hub 2. ing. Also, a pair of sensors 7a and 7b are supported and fixed inside a metal plate-made bottomed cylindrical cover 5 that closes the axially inner end opening of the outer ring 1 via a synthetic resin sensor holder 6. is doing. In this state, the detection portions of both the sensors 7 a and 7 b are made to face and face each other on the outer peripheral surface that is the detection surface of the encoder 4.

  Of these, the encoder 4 is made of a magnetic metal plate. Through holes 8 and 8 and column portions 9 and 9 are alternately arranged at equal intervals in the circumferential direction in the front half (axially inner half) of the encoder 4. The boundaries between the through holes 8 and 8 and the pillars 9 and 9 are inclined by the same angle with respect to the axial direction (width direction) of the detection surface, and the inclination direction with respect to the axial direction is determined by the detection target. The directions are opposite to each other with the axial middle portion of the surface as a boundary. Accordingly, each of the through holes 8 and 8 and each of the column portions 9 and 9 has a "<" shape with an axially intermediate portion protruding most in the circumferential direction. And among the axially outer half part and the axially inner half part of the detected surface, the boundary inclination directions are different from each other, the axially outer half part is defined as the first characteristic changing part 10, and the axially inner half part Is the second characteristic changing unit 11.

  Further, the sensor holder 6 is held and fixed at the inner end in the radial direction of the cover 5, and the disc portion 12 existing at the inner end portion and the outer peripheral edge portion of the disc portion 12 are pivoted. And a cylindrical portion 13 extending outward in the direction. The two sensors 7a and 7b are embedded and supported in the cylindrical portion 13. Each of these sensors 7a and 7b is composed of a permanent magnet and a magnetic sensing element such as a Hall IC, a Hall element, an MR element, or a GMR element that constitutes a detection unit. Of these sensors 7a and 7b, the detection part of one sensor 7a is close to the first characteristic change part 10 and the detection part of the other sensor 7b is close to the second characteristic change part 11, respectively. Yes. No axial load is applied between the outer ring 1 and the hub 2, and the outer rings 1 and the hub 2 are not displaced relative to each other in the axial direction. The axial position of each member is such that the most protruding portion in the circumferential direction at the axially intermediate portion of the portions 9 and 9 is located at the central position between the detection portions of the sensors 7a and 7b. Is regulated. In the same state, the installation positions of the sensors 7a and 7b in the circumferential direction so that the relationship between the detection portions of the sensors 7a and 7b and the phase of the characteristic change of the outer peripheral surface of the encoder 4 is as specified. Is regulated.

  In the state quantity measuring device of the rolling bearing unit configured as described above, in the neutral state, the detecting portions of the sensors 7a and 7b are shafts from the most protruding portion of the outer peripheral surface of the encoder 4. Opposite the same part in the direction. For this reason, the phase difference between the output signals of the sensors 7a and 7b is a value determined by the predetermined relationship. On the other hand, when an axial load acts between the outer ring 1 and the hub 2 and the outer ring 1 and the hub 2 are relatively displaced in the axial direction, the detecting portions of the sensors 7a and 7b are Out of the outer peripheral surface of the encoder 4, it faces a portion that is shifted in the direction corresponding to the acting direction of the axial load (the direction of the relative displacement) by an amount corresponding to the magnitude of the axial load (relative displacement). As a result, the phase difference between the output signals of the sensors 7a and 7b is shifted in the direction corresponding to the direction of action of the axial load by an amount corresponding to the magnitude of the axial load. Therefore, based on this phase difference, the direction and magnitude of the relative displacement in the axial direction between the outer ring 1 and the hub 2, the direction of the axial load acting between the outer ring 1 and the hub 2, and The size is required. The processing for calculating the relative displacement and the load in the axial direction based on the phase difference (phase difference ratio = phase difference / 1 period) is performed by a calculator (not shown). For this reason, in the memory of this computing unit, formulas and maps representing the relationship between the phase difference (ratio) and the relative displacement or load in the axial direction, which have been examined in advance by theoretical calculation or experiment, are stored. Let me.

  In the case of the first example of the conventional structure described above, the number of sensors that make the detection portion face the detection surface of the encoder is two. On the other hand, although not shown in the drawings, Patent Documents 2 to 3 and Japanese Patent Application No. 2006-345849 describe structures in which displacement or external force with multiple degrees of freedom is obtained by setting the number of sensors to three or more. Has been.

  Next, FIGS. 4-5 has shown the 2nd example of the conventional structure regarding the state quantity measuring apparatus of a rolling bearing unit. In the case of the second example of this conventional structure, slit-like through holes 8a and 8a and a column are formed on the tip half of a magnetic metal plate and cylindrical encoder 4a that is fitted and fixed to the inner end of the hub 2 in the axial direction. The portions 9a and 9a are alternately arranged at equal intervals in the circumferential direction. The boundaries between the through holes 8a and 8a and the pillars 9a and 9a are linear shapes that are inclined by the same angle in the same direction with respect to the axial direction of the encoder 4a. Further, the detection portions of a pair of sensors 7a and 7b supported on the inner end portion in the axial direction of the outer ring 1 via the cover 5 and the sensor holder 6 are placed close to and opposed to the two upper and lower positions of the detected surface.

  In the case of a rolling bearing unit for supporting a wheel of an automobile, an axial load applied between the outer ring 1 and the hub 2 is input from a ground contact surface between a tire outer peripheral surface and a road surface constituting a wheel coupled and fixed to the hub 2. Is done. Since this ground contact surface exists radially outward from the center of rotation of the outer ring 1 and the hub 2, the axial load is not between the outer ring 1 and the hub 2 but as a pure axial load. And a moment in a virtual plane (in the vertical direction) including the center axis of the hub 2 and the center of the ground plane. When such a moment is applied between the outer ring 1 and the hub 2, the central axis of the hub 2 is inclined with respect to the central axis of the outer ring 1. Accordingly, the upper end of the encoder 4a is displaced in any direction with respect to the axial direction, and the lower end is similarly displaced in the opposite direction. As a result, the phases of the output signals of the sensors 7a and 7b, in which the detection units are placed close to and opposed to the upper and lower ends of the outer peripheral surface of the encoder 4a, are shifted in the opposite directions with respect to the neutral positions. That is, the phase difference between the output signals of both the sensors 7a and 7b changes in accordance with the acting direction and magnitude of the axial load. Therefore, the action direction and magnitude of the axial load can be obtained based on the phase difference between the output signals of both the sensors 7a and 7b.

  Next, FIGS. 6 to 7 show a third example of a conventional structure related to a state quantity measuring device for a rolling bearing unit. In the case of the third example of this conventional structure, through holes 8b and 8b and a column portion 9b are formed in the tip half of a cylindrical encoder 4b made of a magnetic metal plate that is fitted and fixed to the inner end of the hub 2 in the axial direction. 9b are arranged alternately at equal intervals in the circumferential direction. Each of these through holes 8b, 8b has a trapezoidal shape when viewed from the radial direction, and gradually changes the width dimension in the circumferential direction with respect to the axial direction. Further, the detection portion of one sensor 7a supported on the inner end in the axial direction of the outer ring 1 via the cover 5 and the sensor holder 6 is a circumference of the outer peripheral surface of the front half of the encoder 4b, which is a detected surface. It is made to face and oppose part of the direction (lower end in the illustrated example). In the third example of the conventional structure configured as described above, when the outer ring 1 and the hub 2 are relatively displaced in the axial direction based on the axial load, the duty ratio of the output signal of the sensor 7a (high potential duration time / 1 (Period) changes. Therefore, based on this duty ratio, the direction and magnitude of the relative displacement, and further the direction and magnitude of the axial load can be obtained.

By the way, when adopting a structure in which the sensor 7a (7b) is installed in the cover 5 attached to the inner end of the outer ring 1 in the axial direction as in the conventional structures described above, the sensor 7a (7b) It may be difficult to design the cover 5 at a desired position. The reason for this will be described below with reference to FIG.
Note that the state quantity measuring device for the wheel supporting bearing unit shown in FIG. 8 is the one described in the Japanese Patent Application No. 2006-345849 (the structure of the prior invention), and the first to third examples of the conventional structure described above. Similarly to the above, the sensor 7a (7b) is installed in the cover 5 mounted on the inner side in the axial direction of the outer ring 1. In the case of the structure according to the prior invention, three circumferential positions of the first and second characteristic changing portions 10 and 11 in the outer circumferential surface of the encoder 4 supported and fixed to the inner end portion in the axial direction of the hub 2 (total Each of the detection portions of the sensors 7a (7b) is closely opposed to each other at six locations (in FIG. 8, only four sensors 7a and 7b are shown for convenience). These sensors 7 a and 7 b are embedded in a sensor holder 6 that is held and fixed in the cover 5. According to such a structure of the prior invention, based on the phase difference ratio between the output signals of the sensors 7a and 7b, a multi-degree-of-freedom relative displacement between the outer ring 1 and the hub 2, and A multi-degree of freedom external force acting between the outer ring 1 and the hub 2 is required. However, since this point is not a characteristic part of the present invention, further detailed explanation is omitted.

In any case, when assembling the wheel support bearing unit with the cover 5 mounted on the vehicle, as shown in FIGS. 8A to 8B, the axially inner end of the wheel support bearing unit is shown. The part is inserted inside a circular support hole 15 provided in the knuckle 14 constituting the suspension device. Accordingly, the fitting cylindrical surface portion 16 provided on the outer peripheral surface of the outer ring 1 near the inner end in the axial direction is fitted into the support hole 15 without rattling. At the same time, the axially inner side surface of the coupling flange 17 provided on the outer peripheral surface of the outer ring 1 is abutted against the axially outer surface of the knuckle 14. In this state, the coupling flange 17 is coupled and fixed to the knuckle 14 with a bolt (not shown). Therefore, the outer diameter of the cover 5 needs to be equal to or smaller than the outer diameter of the fitting cylindrical surface portion 16 so that the above-described insertion operation can be performed. As a result of such dimensional restrictions, the space in the cover 5 is narrowed, so that the degree of freedom of arrangement of the sensors 7a and 7b in the cover 5 is limited. In particular, when adopting a structure in which the number of the sensors 7a and 7b is three or more (six) as in the structure of the prior invention shown in FIG. 8, the number of the sensors 7a and 7b Along with the increase, the number of lead wires (for signal extraction and power supply) to be arranged in the cover 5 together with the sensors 7a and 7b increases. For this reason, the freedom degree of arrangement | positioning of each said sensor 7a, 7b in the said cover 5 is restrict | limited more.
Accordingly, when the structure in which the sensor 7a (7b) is installed in the cover 5 attached to the inner end in the axial direction of the outer ring 1 as in the above-described conventional structures and the structure of the previous invention, the sensor 7a It may be difficult to design (7b) at a desired position in the cover 5.

JP 2006-317420 A JP 2006-322928 A JP 2006-194673 A

  The state quantity measuring device for a rolling bearing unit according to the present invention has been invented in order to realize a structure capable of increasing the degree of freedom of arrangement of a sensor opposed to a detection surface of an encoder in view of the above-described circumstances.

The rolling bearing unit state quantity measuring apparatus of the present invention includes a rolling bearing unit and a state quantity measuring apparatus.
Of these, the rolling bearing unit is supported concentrically with the stationary side bearing ring through a plurality of rolling elements and not stationary while being supported and fixed to the suspension system of the vehicle. And a hub that rotates together with the wheel while the wheel is supported and fixed.
The state quantity measuring device includes an encoder, at least one sensor, and a calculator.
Of these, the encoder is supported and fixed concentrically with the hub at the end of the hub, and includes a detected surface concentric with the hub, and the characteristics of the detected surface are alternately set in the circumferential direction. It is changing.
In addition, the sensor is supported and fixed to a portion that does not rotate during use with the detection portion facing the detection surface of the encoder, and changes the output signal in response to a change in the characteristics of the detection surface. Let
Further, the computing unit is based on an output signal of the sensor, and includes a rotation speed of the hub, a relative displacement between the outer ring and the hub, and an external force acting between the outer ring and the hub. It has a function of calculating at least one kind of state quantity.

In particular, in the state quantity measuring device of the rolling bearing unit of the present invention, the portion that supports and fixes the sensor, and the portion that does not rotate during use is part of the suspension device (part of the knuckle, axle caliper, etc.). It is.
When carrying out the present invention having such characteristics, for example, as described in claim 2, the sensor is embedded and supported in a sensor holder made of synthetic resin having at least an annular portion. Support and fix to a part of the suspension system.

  According to the state quantity measuring device of the rolling bearing unit of the present invention configured as described above, it is attached to the inner end in the axial direction of the outer ring which is a stationary side race ring, as in the above-described conventional structures and the structure of the previous invention. Compared to the structure in which the inner space of the cover is the sensor placement space, the degree of freedom of sensor placement can be increased. That is, as described above, in the case of each of the conventional structures and the structures of the prior invention, the outer diameter dimension of the cover is set to the inner diameter dimension of the support hole provided in the knuckle constituting the suspension device. It is necessary to make it smaller than the outer diameter dimension of the inner end portion in the axial direction of the outer ring. For this reason, the outer diameter dimension of the inner space of the cover, that is, the sensor arrangement space is necessarily smaller than the inner diameter dimension of the support hole. On the other hand, in the case of the present invention, since the sensor is supported and fixed to a part of the suspension device, it is possible to make the outer diameter dimension of the arrangement space of the sensor larger than the inner diameter dimension of the support hole. Therefore, in the case of the present invention, the degree of freedom of sensor arrangement can be increased as compared with the conventional structures and the structures of the previous invention. As a result, it is easy to design the sensor at a desired position.

  FIG. 1 shows an example of an embodiment of the present invention. A feature of this example is a support structure for a plurality (six) of sensors 7a and 7b. Since the structure and operation of the other parts are the same as the structure of the prior invention shown in FIG. 8 described above, the same reference numerals are given to the equivalent parts, and redundant explanations are omitted or simplified. The description will focus on the characteristic part.

  Also in the case of this example, as in the case of the structure of the previous invention, the knuckle that constitutes the suspension device is formed on the inner end in the axial direction of the outer ring 1 with the wheel support bearing unit assembled to the vehicle as shown in the figure. 14 is fixedly coupled. Specifically, the fitting cylindrical surface portion 16 provided on the outer peripheral surface of the outer ring 1 near the inner end in the axial direction is fitted into the support hole 15 provided in the knuckle 14 without rattling. At the same time, the axially inner side surface of the coupling flange 17 provided on the outer peripheral surface of the outer ring 1 is abutted against the axially outer surface of the knuckle 14. In this state, the coupling flange 17 is coupled and fixed to the knuckle 14 with a bolt (not shown). However, in this example, the sensors 7a and 7b are not supported and fixed to the inner end of the outer ring 1.

  In the case of this example, the sensors 7 a and 7 b are supported and fixed to the knuckle 14. For this purpose, a circular mounting hole 20 whose inner diameter dimension is larger than the inner diameter dimension of the support hole 15 is formed in a part of the knuckle 14 adjacent to the inner side in the axial direction of the support hole 15. 15 and concentric. The sensors 7a and 7b are supported inside the mounting hole 20 via the cover 5a and the sensor holder 6a. Of these, the cover 5a is formed of a metal plate in the shape of a bottomed cylinder, and includes a bottom plate portion 18 and a cylindrical portion 19 that extends outward in the axial direction from the outer peripheral edge portion of the bottom plate portion 18. Prepare. Then, the mounting hole 20 is closed by fitting (press-fitting) the cylindrical portion 19 into the mounting hole 20 from the inner side in the axial direction. The sensor holder 6a is integrally formed of synthetic resin and is held and fixed inside the cover 5a. Such a sensor holder 6a includes a disc portion 21 attached to the inner surface (axially outer surface) of the bottom plate portion 18 and an annular portion 22 having a rectangular cross section attached to the inner peripheral surface of the cylindrical portion 12a. With. The sensors 7a and 7b are embedded in the surface layer portion of the inner peripheral surface of the annular portion 22, respectively. In this state, the first and second characteristic changing portions 10 and 11 are provided on the outer peripheral surface of the encoder 4 in which the detection portions of the sensors 7a and 7b are supported and fixed at the inner end portions in the axial direction of the hub 2, respectively. Are placed close to each other in the circumferential direction. In this state, the harness 23 connected to the sensors 7a and 7b is led out to the outside through a through hole 24 formed in a part of the bottom plate portion 18 of the cover 5a.

  According to the state quantity measuring device of the rolling bearing unit of the present example configured as described above, the cover 5 attached to the inner end in the axial direction of the outer ring 1 as in the structure of the previous invention shown in FIG. Compared to a structure in which the inner space is an arrangement space for a plurality of (six) sensors 7a and 7b, the degree of freedom of arrangement of these sensors 7a and 7b can be increased. That is, as described above, in the case of the structure of the above invention, the outer diameter of the cover 5 is set to the inner diameter of the support hole 15 of the knuckle 14 (for fitting the outer ring 1 fitted into the support hole 15. It is necessary to make it smaller than the outer diameter dimension of the cylindrical surface portion 16. For this reason, the outer diameter dimension of the inner space of the cover 5, that is, the arrangement space of the sensors 7 a and 7 b inevitably becomes smaller than the inner diameter dimension of the support hole 15. On the other hand, in the case of this example, a cover 5a having the inner space as an arrangement space for the sensors 7a and 7b is provided in a part of the knuckle 14, and the inner diameter is the inner diameter of the support hole 15. It is fitted and fixed in the mounting hole 20 larger than the dimension. For this reason, the inner diameter of the cover 5 a, that is, the outer diameter of the arrangement space (sensor holder 6 a) of the sensors 7 a and 7 b can be made larger than the inner diameter of the support hole 15. Therefore, in the case of this example, the degree of freedom of arrangement of the sensors 7a and 7b can be increased as compared with the structure of the prior invention. As a result, it is easy to design the sensors 7a and 7b at desired positions.

  The present invention is not limited to the structure of the above-described embodiment, and can be implemented for various structures that satisfy the requirements described in the claims. For example, the present invention can be implemented for a structure that employs a combination of encoders 4, 4a, 4b and sensors 7a, 7b, such as the conventional structures shown in FIGS. In addition, the present invention has a structure in which an encoder made of a permanent magnet (an S pole and an N pole are alternately arranged on the detection surface) is incorporated (in this structure, there is no need to incorporate a permanent magnet on the sensor side). ), Or by measuring the radial load acting between the stationary race ring and the hub by making the detection surface of the encoder an annular surface and making the detection part of the sensor face the detection surface in the axial direction. It can also be implemented for a possible structure.

Sectional drawing which shows one example of embodiment of this invention in the state couple | bonded and fixed to the knuckle which comprises a suspension apparatus. Sectional drawing which shows the 1st example of the conventional structure of the state quantity measuring apparatus of a rolling bearing unit. The figure which looked at a part of encoder incorporated in this 1st example from the diameter direction. Sectional drawing which shows the 2nd example of the conventional structure of the state quantity measuring apparatus of a rolling bearing unit. The figure which looked at a part of encoder incorporated in this 2nd example from the diameter direction. Sectional drawing which shows the 3rd example of the conventional structure of the state quantity measuring apparatus of a rolling bearing unit. The figure which looked at a part of encoder incorporated in this 3rd example from the diameter direction. A fourth example of a conventional structure of a state quantity measuring device for a rolling bearing unit is shown in a state before (A) is coupled and fixed to a knuckle constituting a suspension device, and (B) is a state after coupled and fixed. Sectional drawing.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Outer ring 2 Hub 3 Rolling element 4, 4a, 4b Encoder 5, 5a Cover 6, 6a Sensor holder 7a, 7b Sensor 8, 8a, 8b Through-hole 9, 9a, 9b Pillar part 10 First characteristic change part 11 Second characteristic Change part 12, 12a Disc part 13, 13a Cylindrical part 14 Knuckle 15 Support hole 16 Fitting cylindrical surface part 17 Connection flange 18 Bottom plate part 19 Cylindrical part 20 Mounting hole 21 Disc part 22 Ring part 23 Harness 24 Through hole

Claims (2)

A rolling bearing unit and a state quantity measuring device;
Of these, the rolling bearing unit is supported concentrically with the stationary side bearing ring through a plurality of rolling elements and not stationary while being supported and fixed to the suspension system of the vehicle. It is equipped with a hub that rotates with this wheel while the wheel is supported and fixed,
The state quantity measuring device includes an encoder, at least one sensor, and a computing unit,
Of these, the encoder is supported and fixed concentrically with the hub at the end of the hub, and includes a detected surface concentric with the hub, and the characteristics of the detected surface are alternately set in the circumferential direction. Is a change,
The sensor is supported and fixed to a portion that does not rotate during use with the detection unit facing the detection surface of the encoder, and changes the output signal in response to a change in characteristics of the detection surface. And
The computing unit is based on the output signal of the sensor, among the rotational speed of the hub, the relative displacement between the outer ring and the hub, and the external force acting between the outer ring and the hub, It has a function of calculating at least one kind of state quantity.
In the state quantity measuring device of the rolling bearing unit,
A state quantity measuring device for a rolling bearing unit, wherein a portion which does not rotate during use, which is a portion for supporting and fixing the sensor, is a part of the suspension device.   The state quantity measuring device of a rolling bearing unit according to claim 1, wherein the sensor is supported and fixed to a part of the suspension device in a state of being embedded and supported in a sensor holder made of synthetic resin having at least an annular portion.

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