JP2006090509A - Rolling bearing unit with sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rolling bearing unit with a sensor of low cost and high resolution by utilizing a resolver of high resolution, and lowering its cost. <P>SOLUTION: A sensor device comprises the resolver 2 composed of a rotor 8 mounted on a rotation-side raceway member 4 and a stator 7 mounted on a fixed-side raceway member 3. The rotor 8 is constituted as a mechanical processed component independent from the rotation-side raceway member 4, and has an elliptic cross-sectional shape 8a on its outer peripheral face as a detected surface. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a rolling bearing unit with a sensor in which a rolling bearing and a sensor device for detecting various types of information are integrated.

  In railway vehicles and automobiles, the rotation side track member to which the wheel is attached and the vehicle body side are fixed to support the axle or the rotation axis that transmits the rotation to the axle and to detect the rotation speed, rotation angle, etc. Used is a rolling bearing unit with a sensor (a hub unit with a sensor) which includes a fixed side raceway member, a rolling bearing having rolling elements arranged between the raceway members, and a sensor device provided in the rolling bearing. ing.

  In this type of rolling bearing unit with a sensor, there is an increasing demand for improved resolution and smaller diameter for rotation detection. However, in the case of using pulsar ring, the resolution depends on the number of magnetic poles of pulsar ring. It is necessary to increase the number of poles. However, if this is done, the magnetic flux density becomes low, the absolute value of the signal output of the sensor device becomes small, and there is a problem that rotation cannot be measured accurately, so there is a limit to improving the resolution.

Therefore, as a rolling bearing unit with a sensor that uses a detected portion instead of pulsar ring, Patent Document 1 discloses a detecting portion that is sandwiched between protrusions of a detected member that is formed in a substantially U shape having a plurality of protrusions. Has been disclosed in which the detection output of the rotational speed is improved, and in Patent Document 2, the shape accuracy is improved by externally fitting the detected portion to the nut for fixing the bearing device. A structure that can be increased and that improves detection accuracy is disclosed.
Japanese Utility Model Publication No. 6-47867 Japanese Patent Laid-Open No. 11-174069

  In the rolling bearing unit with a sensor of the above-mentioned patent document, the thing of patent document 1 has a problem that processing of a detected member is troublesome, and the thing of patent document 2 is applied to the bearing device which does not have a nut. There was a problem that I could not.

  Therefore, it is conceivable to obtain a rolling bearing unit with a sensor that can detect a rotation state and a ground load using a VR resolver having a high resolution consisting of a stator and a rotor. The shape of a conventional VR resolver is as follows: Since it is formed in a special shape by superposing silicon steel plates that have been subjected to sheet metal processing, there is a problem that the cost is high if this is used as it is. In order to reduce the cost, the outer diameter of the rotor may be machined into a non-circular shape, but in this case, the output waveform is likely to be distorted, which results in an angle reading error, resulting in the high resolution characteristics of the resolver. There is a problem that it cannot be saved.

  An object of the present invention is to provide a rolling bearing unit with a sensor that uses a high-resolution resolver and suppresses an increase in the manufacturing cost as much as possible to obtain an output waveform with less distortion. .

  A rolling bearing unit with a sensor according to a first invention comprises a rolling bearing having a rotating side race member, a fixed side race member, and a rolling element disposed between the race members, and a sensor device provided in the rolling bearing. In the sensor-equipped rolling bearing unit, the sensor device includes a resolver including a rotor provided on the rotation-side raceway member and a stator provided on the fixed-side raceway member, and a cross-sectional shape of the outer peripheral surface of the rotor serving as a detection surface Is an ellipse.

  If the detected surface of the rotor is formed of two eccentric surfaces or has a notched shape, a discontinuous surface is generated on the detected surface, and this tends to cause an angle reading error due to harmonic noise. . Therefore, in order to eliminate an angle reading error due to harmonic noise, the outer peripheral surface shape of the rotor is an ellipse. Since the elliptical shape can be expressed by a simple quadratic function or a simple polar coordinate display, a rotor having an elliptical outer peripheral surface shape can be formed by machining (cutting).

  A rolling bearing unit with a sensor according to a second invention comprises a rolling bearing having a rotating side race member, a fixed side race member, and a rolling element disposed between both raceway members, and a sensor device provided in the rolling bearing. In the sensor-equipped rolling bearing unit, the sensor device includes a resolver including a rotor provided on the rotation-side raceway member and a stator provided on the fixed-side raceway member, and a cross-sectional shape of the outer peripheral surface of the rotor serving as a detection surface Is formed by two eccentric circular arc surfaces opposed to each other and two perfect circular circular arc surfaces that face each other and connect the ends of both eccentric circular arc surfaces.

  If the detected surface of the rotor is formed of two eccentric surfaces or has a notched shape, a discontinuous surface is generated on the detected surface, and this tends to cause an angle reading error due to harmonic noise. . Therefore, in order to eliminate an angle reading error due to harmonic noise, the rotor outer peripheral surface shape is formed by two eccentric circular arc surfaces facing each other and two circular circular arc surfaces facing each other and connecting the ends of both eccentric circular arc surfaces. It is formed. Such a shape can be obtained by combining a plurality of cylindrical surfaces having different shapes, and can be formed by machining (cutting).

  In the rolling bearing unit with sensor of the first and second inventions, the rotor may be a separate member from the rotation side race member, and the rotation side race member is cut by cutting the outer diameter or inner diameter of the rotation side race member. Alternatively, the detected surface of the rotor may be formed integrally.

  The resolver is known as a rotation angle detection device. When the rotation-side track member and the fixed-side track member rotate relative to each other in a state where a sine wave voltage is input to the stator, the air between the stator and the detected surface of the rotor is detected. Along with the continuous change of the gap amount, a voltage corresponding to the rotation angle is obtained in the stator, whereby the rotation state of the rolling bearing can be detected.

  The resolver stator includes, for example, a ring-shaped iron core whose inner diameter is formed in a comb-teeth shape, and a stator winding formed by sequentially winding coils around all tooth portions. The stator is fixed by being press-fitted into the shoulder portion of the fixed-side track member with the iron core portion having the tip of the tooth radially inward.

  The resolver is usually arranged at the end of the rolling bearing, but when the rolling bearing is a double row, it may be arranged in the middle of the two rows of rolling elements. As the resolver, various types of brushless resolvers and brushless synchros can be used, and among these, a VR (variable reactance) type resolver is preferable.

  The sensor device is provided with a processing circuit for processing a signal output in accordance with an air gap amount between the stator and the detected surface of the rotor. It is preferable to have a rotation detection unit that obtains the rotation speed and a wheel contact load calculation unit that obtains a contact load applied to the wheel from an air gap amount between the stator and the rotor.

  According to the rolling bearing unit with sensor of the first and second inventions, the sensor device includes a resolver including a rotor provided on the rotating side raceway member and a stator provided on the fixed side raceway member. A change in the gap amount with the stator is magnetically detected by the resolver, and the rotation angle of the rotor is output as a voltage change. The rotor has an elliptical outer circumferential surface shape, or two true cross-sectional shapes of the rotor that are opposed to two eccentric arc surfaces facing each other and that connect the ends of both eccentric arc surfaces. Since it is formed by a circular arc surface, it can be manufactured by machining, and compared with the superposition of sheet metal-worked silicon steel sheets, the cost can be reduced and compared with the cut product by normal machining Thus, it is possible to obtain an output waveform with less distortion, and to balance the reduction in cost and the output waveform characteristic with less distortion, which are conflicting problems, at a high level, and to make use of the characteristics of the resolver with high resolution.

  Embodiments of the present invention will be described below with reference to the drawings.

  1 and 2 show a first embodiment of a rolling bearing unit with a sensor according to the first invention. In the following description, left and right and top and bottom refer to left and right and top and bottom of the drawing.

  As shown in FIGS. 1 and 2, the sensor-equipped rolling bearing unit includes a rolling bearing (1) and a resolver (2) that detects its rotation.

  The rolling bearing (1) includes an outer ring (3) that is a fixed side race member, an inner ring (4) that is a rotary side race member, balls (5) that are a plurality of rolling elements arranged therebetween, and a cage. (6) is provided. Although not shown, the outer ring (3) is fixed to a housing or the like, and a rotating shaft or the like is fixed to the inner ring (4).

  The resolver (2) is a VR type brushless resolver, which is composed of a stator (7) and a rotor (8). The stator (7) is fixed to the outer ring (3), and the rotor (8) is fixed to the inner ring (4). ing.

  The stator (7) has a ring-shaped iron core (9) whose inner diameter is formed in a comb-teeth shape, and a stator winding (10) formed by sequentially winding coils around all teeth of the iron core (9). It consists of. The stator (7) is fixed by being press-fitted into the right end of the outer ring (3) with the iron core (9) having the tips of the teeth radially inward. Thus, the inner diameter of the iron core (9) of the stator (7) is concentric with the inner diameter of the outer ring (3).

  As shown in FIG. 2, the rotor (8) is formed by machining separately from the inner ring (4) so that the cross-sectional shape (8a) of the outer peripheral surface serving as the detected surface becomes a continuously changing ellipse. The cross-sectional shape (8b) of the inner peripheral surface is an ellipse and a circle having the same center, and is fixed by press-fitting into an annular groove (4a) provided in the inner ring (4). In FIG. 1, the upper side is the short diameter of the rotor (8) (the gap between the stator (7) and the rotor (8) is maximum), and the lower side is the long diameter of the rotor (8) (stator (7) and rotor (8) ) And the lower gap are drawn to show the minimum).

  Therefore, when the inner ring (4) rotates, the gap between the iron core (9) of the stator (7) having an inner diameter that is concentric with the inner diameter of the outer ring (3) and the rotor (8) having an elliptical detection surface (8a). Changes, a voltage corresponding to the rotation angle is obtained in the stator (7), and this is sent to the processing circuit via the signal line (11). Thereby, the rotation state of the inner ring (4) can be detected.

The rotor (58) is machined when forming a different gap [delta] ₁ and [delta] ₂ between the stator (7), as shown in FIG. 6 (a), the eccentricity of the detected face of the rotor (58) It is conceivable to provide notches (58d) on the cylindrical surface as shown in FIG. 6 (b), or as cylindrical surfaces (58b) and (58c). In FIG. 6 (a), the eccentric cylindrical surfaces (58b) and (58c) are opposite to the arc (first circumferential surface) (58b) having a radius r centered at a position away from the rotation center by a predetermined distance. It is formed by an arc (second peripheral surface) (58c) having a radius r centered at a position separated by a predetermined distance in the direction. Such eccentric cylindrical surfaces (58b) (58c) can be obtained by machining with the axis of the turning tool eccentric twice with respect to the central axis. In this case, the portion indicated by J in the figure becomes discontinuous, creating harmonic noise, and causing a problem of error. In FIG. 6 (b), the notch (8d) is formed by setting the width of the two opposing surfaces to B. The notch (8d) has a portion indicated by S in the figure. There is a problem that it becomes discontinuous and creates harmonic noise, causing an error. In any case, since the shape is obtained by machining, there is a sharp discontinuous surface. Therefore, there is a problem that the output waveform is distorted and easily causes an angle reading error. On the other hand, according to the profile (elliptical shape) of the rotor (8) shown in FIG. 2, since the discontinuous portion can be eliminated, the distortion of the output waveform can be suppressed and the detection accuracy can be increased.

  Moreover, when forming a rotor by machining, it can also be set as the shape shown in FIG. The first embodiment of the sensor-equipped rolling bearing unit of the second invention is obtained by replacing the rotor (8) of the sensor-equipped rolling bearing unit shown in FIG. 1 with the rotor (18) shown in FIG. can get. The rotor (18) has the same inner peripheral surface (18b) as the rotor (8) shown in FIG. And the outer peripheral surface cross-sectional shape (18a) which becomes the to-be-detected surface is between the two eccentric arc surfaces (r1) and (r2) facing each other, and the ends of both eccentric arc surfaces (r1) and (r2) facing each other. Are formed by two circular circular arc surfaces (r3) and (r4). The first eccentric arc surface (r1) is a circular arc with a radius R1 centered on a position P that is a distance d away from the center of rotation, and the second eccentric arc surface (r2) is relative to P from the center of rotation. The third and fourth perfect circular arc surfaces (r3) and (r4) have a radius R2 centered on the center of rotation. This is an arc of a circle. Here, (R1-d) <R2 <R1 is established, and thus a substantially smooth non-circular cross-sectional shape having a minimum radius of (R1-d) and a maximum radius of R2 is obtained.

  2 and 3, the rotor (8) and (18) are formed by machining to reduce the cost, and the shape and the cutting formed by two eccentric surfaces can be achieved while machining. A discontinuous surface generated when a notch is formed can be avoided, the degree of freedom of gap adjustment is increased, and an output waveform with less distortion can be obtained. The rotors (8) and (18) are separate members from the inner ring (4), but by cutting the inner diameter of the inner ring (4) into a predetermined shape, the rotor (8) is integrated with the inner ring (4). 8) (18) can also be formed.

  FIG. 4 shows a second embodiment of the rolling bearing unit with sensor of the first and second inventions. As shown in the figure, the sensor-equipped rolling bearing unit includes a double row rolling bearing (21) and a resolver (22) for detecting the rotation thereof.

  The rolling bearing (21) is a double row angular contact ball bearing, and is arranged in two rows between an outer ring (23) as a fixed side race member and two inner rings (24) as a rotary side race member. In addition, a ball (25), which is a plurality of rolling elements, and a cage (26) for holding each row of balls (25) are provided. Although not shown, the outer ring (23) is fixed to a housing or the like, and a rotating shaft or the like is fixed to the inner ring (24).

  The resolver (22) is a VR brushless resolver, and includes a stator (27) and a rotor (28). The stator (27) is fixed to the outer ring (23), and the rotor (28) is fixed to the inner ring (24). ing.

  The stator (27) includes a ring-shaped iron core (29) having an inner diameter formed in a comb-like shape, and a stator winding (30) formed by sequentially winding coils around all teeth of the iron core (29). It consists of. The stator (27) is press-fitted and fixed substantially in the center in the axial direction of the outer ring (23) with the iron core (29) having the tips of the teeth radially inward. Thus, the inner diameter of the iron core (29) of the stator (27) is concentric with the inner diameter of the outer ring (23).

  The rotor (28) of the resolver (22) has a similar shape to the rotor (8) of FIG. 2 or the rotor (18) of FIG. The stator (27) is shifted slightly to the right from the center of the outer ring (23) in the axial direction, and the iron core (29) is positioned so as to face the left end of the right inner ring (24). The rotor (28) is press-fitted and fixed in an annular groove (24a) provided at the left end of the right inner ring (24). Therefore, when the inner ring (24) rotates, the rotor (28) having the iron core (29) of the stator (27) having the inner diameter concentric with the inner diameter of the outer ring (23) and the detected surface (28a) of an elliptical or eccentric cylindrical surface. The voltage corresponding to the rotation angle is obtained in the stator (27), and this is sent to the processing circuit via the signal line (31). Thereby, the rotation state of the inner ring (24) can be detected.

  In the first and second embodiments, the outer rings (3) and (23) are on the fixed side and the inner rings (4) and (24) are on the rotating side, but the outer rings (3) and (23) are on the rotating side and the inner rings. (4) (24) may be the fixed side. In this case, the rotor is provided on the inner diameter of the outer ring (3) (23), and the stator is provided on the outer diameter of the inner ring (4) (24).

  FIG. 5 shows a third embodiment of the sensor-equipped rolling bearing unit according to the first and second inventions.

  As shown in the figure, the sensor-equipped rolling bearing unit includes an automobile hub unit (41) as a rolling bearing and a resolver (42) for detecting the rotation thereof.

  The hub unit (41) is arranged in two rows between a fixed-side track member (43) fixed to the vehicle body side, a rotation-side track member (44) to which wheels are attached, and both members (43) (44). A ball (45), which is a plurality of rolling elements, and a cage (46) for holding each row of balls (45) are provided.

  The fixed side raceway member (43) is provided near the left end of the cylindrical part (52), in which two rows of outer ring raceways are formed on the inner peripheral surface. And a flange portion (53) to be attached. The rotation-side raceway member (44) includes a large-diameter portion (55) having a first raceway groove (55a) and a step-like small-diameter portion having an outer diameter smaller than the diameter of the first raceway groove (55a) ( 56) and a ring portion (57) fitted to the outer diameter of the small diameter portion (56) of the shaft portion (54). A male screw part is formed at the left end of the shaft part (54), and the ring part (57) is brought into close contact with the left end surface of the large diameter part (55) of the shaft part (54). The nut (58) is screwed together. Near the right end of the shaft portion (54), there is provided a flange portion (60) to which a plurality of bolts (59) for attaching a wheel are fixed. A raceway groove (57a) is formed in the ring part (57) so as to be parallel to the raceway groove (55a) of the shaft part (55). A sealing device (61) is provided between the right end portion of the fixed-side track member (43) and the shaft portion (55).

  The resolver (42) is a VR brushless resolver, and includes a stator (47) and a rotor (48). The stator (47) is a fixed-side track member (43), and the rotor (48) is a rotation-side track member ( 44).

  The stator (47) includes a ring-shaped iron core (49) whose inner diameter is formed in a comb-teeth shape, and a stator winding (50) formed by sequentially winding coils around all teeth of the iron core (49). It consists of. The stator (47) is press-fitted and fixed substantially in the center in the axial direction of the fixed-side track member (43) with the iron core (49) having the tips of the teeth radially inward. Thus, the inner diameter of the iron core (49) of the stator (47) is concentric with the inner diameter of the fixed-side raceway member (43). The inner diameter of the iron core (49) is slightly larger than the outer diameter of the large diameter part (55) of the shaft part (54).

  The rotor (48) of the resolver (42) has a similar shape to the rotor (8) of FIG. 2 or the rotor (18) of FIG. The stepped small-diameter portion (56) of the rotation side raceway member (44) includes an intermediate portion (56a) in which the ring portion (57) is fitted, an intermediate portion (56a), and a large-diameter portion (55). The connecting portion (56b) having an intermediate diameter between them and an external thread portion (56c) provided at the left end of the intermediate portion (56a). The stator (47) is positioned so as to face the right end of the intermediate part (56a) of the small diameter part (56), and the rotor (48) is press-fitted and fixed to the intermediate part (56a) of the small diameter part (56). Thus, it is positioned by the left end surface of the large diameter portion (55). Therefore, when the rotation-side raceway member (44) rotates, the rotor having the iron core (49) of the stator (47) having an inner diameter that is concentric with the inner diameter of the fixed-side raceway member (43) and a detection surface that is an elliptical or eccentric cylindrical surface (48) changes, and a voltage corresponding to the rotation angle is obtained in the stator (47), which is sent to the processing circuit via the signal line (51). Thereby, the rotation state of the rotation side track member (44) can be detected. The rotation angle, rotation speed, rotation speed, and the like of the rotation side raceway member (44) are used as control data such as ABS.

  Although not shown, in the hub unit (41) of the third embodiment, the stator (47) is press-fitted and fixed to the left end portion of the fixed-side track member (43), and the rotor (48) is fixed to the rotation-side track member ( 44) may be fixed to the ring portion (57) or the nut (58).

FIG. 1 is a longitudinal sectional view showing a first embodiment of a rolling bearing unit with a sensor according to the first invention. FIG. 2 is a cross-sectional view showing the shape of the detection surface of the rotor. FIG. 3 is a cross-sectional view showing the shape of the detected surface of the rotor of the first embodiment of the rolling bearing unit with sensor according to the second invention. FIG. 4 is a longitudinal sectional view showing a second embodiment of the rolling bearing unit with sensor according to the first and second inventions. FIG. 5 is a longitudinal sectional view showing a third embodiment of the rolling bearing unit with sensor according to the first and second inventions. FIG. 6 is a cross-sectional view showing the shape of the detected surface of a rotor obtained by machining (a rotor as a comparative example of the present invention).

Explanation of symbols

(1) (21) Rolling bearing
(2) (22) Resolver
(3) (23) Outer ring (fixed side raceway member)
(4) (24) Inner ring (rotating raceway member)
(7) (27) Stator
(8) Rotor (rotor for the first invention)
(18) Rotor (rotor for the second invention)
(28) Rotor
(41) Hub unit (rolling bearing)
(42) Resolver
(43) Fixed track member
(44) Rotating track member
(47) Stator
(48) Rotor

Claims (2)

In a rolling bearing unit with a sensor comprising a rotating side raceway member, a fixed side raceway member, a rolling bearing having a rolling element disposed between both raceway members, and a sensor device provided in the rolling bearing,
The sensor device includes a resolver including a rotor provided on the rotation side raceway member and a stator provided on the fixed side raceway member, and the cross-sectional shape of the outer peripheral surface of the rotor serving as the detection surface is an ellipse. A rolling bearing unit with sensor. In a rolling bearing unit with a sensor comprising a rotating side raceway member, a fixed side raceway member, a rolling bearing having a rolling element disposed between both raceway members, and a sensor device provided in the rolling bearing,
The sensor device includes a resolver including a rotor provided on the rotation-side raceway member and a stator provided on the fixed-side raceway member, and the cross-sectional shape of the rotor outer peripheral surface serving as the detection surface is two eccentrics facing each other. A rolling bearing unit with a sensor, characterized in that it is formed by an arcuate surface and two perfectly circular arcuate surfaces facing each other and connecting the ends of both eccentric arcuate surfaces.

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