JP2001349328A - Rolling bearing, and rotating angle measuring method and mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rolling bearing effecting lengthening of life by taking a structure of keeping a space between rolling elements without a retainer. SOLUTION: In this rolling bearing 1 having plural roller-like rolling elements 4 between an inner ring 3 and an outer ring 2, the respective rolling elements 4 are provided with a permanent magnet 42 so that the direction of magnetic moment is in the same direction along the axis of each rolling element 4, whereby the space between the rolling elements 4 is kept only by repulsive force between the permanent magnets 42.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rolling bearing suitable for use as, for example, an electric motor bearing and having a longer life than a conventional rolling bearing, a method of measuring a rotation angle, and a mechanism.

[0002]

2. Description of the Related Art A conventional rolling bearing has a structure in which a rolling element is held between an outer ring and an inner ring so as to be in contact with both wheels, and a retainer is arranged between the rolling elements to keep a constant distance between the rolling elements. It is. That is, when a rotational force is applied, the inner ring rotates with respect to the outer ring while rotating the rolling element. At this time, the rolling element does not shift due to the function of the retainer.

[0003]

One of the applications of rolling bearings is a main motor used for railway vehicles. However, recent main motors are induction motors, and parts other than the bearings require almost no maintenance. do not do. In other words, by sufficiently extending the life of the bearing, it becomes possible to use the main motor without maintenance for a long time. But,
In the bearing having the conventional structure described above, in addition to the rolling friction generated between the inner ring and the outer ring and the rolling element, sliding friction occurs between the rolling element and the retainer. In a cylindrical roller bearing, sliding friction also occurs between a rolling element end face and a bearing outer ring flange. This sliding friction may cause the rolling elements and the cage to be damaged by wear. Further, the temperature of the bearing increases due to heat generated by the sliding friction. If this temperature rise is large, the bearing undergoes dimensional change due to thermal expansion and becomes unusable. Further, if the temperature rise is large, the deterioration of the lubricant is accelerated, and it becomes necessary to frequently perform maintenance such as replacing the lubricant.

[0004] In view of the above circumstances, the present invention provides a longer life by reducing the amount of friction and thereby increasing the life by reducing the amount of wear, and by reducing the temperature rise during rotation. It is an object of the present invention to provide a rolling bearing that enables the use of a rolling bearing. It is another object of the present invention to provide a rotation angle measurement method and a rotation angle measurement mechanism for measuring a rotation angle of a rotating member supported by the rolling bearing.

[0005]

In order to solve the above-mentioned problems, a first invention according to the present invention is, as described in claim 1, in the form of a roller between an inner ring (3) and an outer ring (2). In the rolling bearing (1) holding a plurality of rolling elements (4), a permanent magnet (42) is attached to each rolling element so that the direction of the magnetic moment is in the same direction as the rotation axis of the rolling element. It is characterized in that the repulsive force between the permanent magnets keeps the distance between the rolling elements.

In the rolling bearing according to the first aspect,
Since the permanent magnets are attached to the rolling elements so that the direction of the magnetic moment is in the same direction along the rotation axis of the rolling elements, the permanent magnets repel each other. For this reason, the rolling elements maintain a distance from each other due to the repulsive force of the permanent magnet.

Therefore, according to the present invention, a rolling bearing without a cage is realized. As a result, the sliding friction portion in the rolling bearing is reduced, and the rolling bearing has a longer life than before. Further, according to the present rolling bearing, the frictional heat is also reduced at the same time, so that the temperature rise during rotation is reduced, and the life of the lubricant is extended. Also, power loss is reduced due to a reduction in frictional force. Furthermore, the weight of the rolling bearing is reduced by omitting the cage.

Here, the permanent magnet may be provided so as to penetrate the rolling element, but as described in claim 2, the permanent magnet is provided on both end faces of the rolling element (for example, the end face of the rolling element main body 41). Each may be attached. In this case, it is not necessary to change the internal structure of the rolling element, and the structural change can be minimized. Further, the strength of the rolling elements can be maintained at the same level as in the related art.
In addition, even if iron powder is generated due to wear of the rolling elements, the iron powder is attracted to the permanent magnets at both ends, so that the rolling elements, the outer ring,
The possibility that the inner ring is damaged by iron powder is reduced, and the life of the rolling bearing is extended.

According to the present invention, the rolling element itself may be a permanent magnet.

Further, according to the present invention, at least one of the outer peripheral surface of the inner ring and the inner peripheral surface of the outer ring (for example, the inner peripheral surface 21) is made of a magnetic material (for example, steel). Alternatively, the surface may be chamfered at the axial end (for example, the tapered surface 21a) to be convex toward the rolling element. With such a configuration, when the rolling element is displaced in the axial direction, an attractive force acts between the chamfered surface and the permanent magnet, but this attractive force also includes a force in a direction to pull the rolling element back toward the center. . Therefore, the rolling elements return to their original positions. Therefore, according to the fourth aspect of the present invention, the rolling elements can be positioned without providing a flange or a groove for inserting and positioning the rolling elements on the outer peripheral surface of the inner race or the inner peripheral surface of the outer race. It is possible to further reduce the friction generated on the moving body and achieve a longer life of the rolling bearing. Therefore, the life of the rolling bearing body and the lubricant is further extended.

Further, according to a second aspect of the present invention, as described in claim 5, a rotation for measuring a rotation angle of a rotating member supported by the rolling bearing according to any one of claims 1 to 4 is provided. An angle measuring method, wherein a magnetic detecting means (for example, a coil 5) is installed close to between an inner ring and an outer ring of a rolling bearing,
Each time the rolling element passes near the magnetic detecting means, the signal generated by the magnetic detecting means is integrated and multiplied by a constant to measure the rotation angle of the rotating member.

When the magnetic detecting means is installed close to the inner ring and the outer ring of the rolling bearing as in the present invention, the rolling element of the rolling bearing passes near the magnetic detecting means with the rotation of the rotating body. By integrating the number of passes through the signal from the magnetic detecting means, the number of rolling elements passing near the magnetic detecting means can be detected. The number of detections is proportional to the rotation angle of the inner ring or the outer ring, that is, the rotation angle of the rotating member. Therefore, according to the configuration of the present invention, the rotation angle of the rotating member can be measured with a simple configuration. Here, a magnetic sensor other than a coil can be used as the magnetic detection means.

Further, the present invention may be configured such that the rotation speed of the rotating member is calculated from the rotation angle per unit time.

Further, according to a third aspect of the present invention, as described in claim 7, a rotation for measuring a rotation angle of a rotating member supported by the rolling bearing according to any one of claims 1 to 4 is provided. An angle measuring mechanism, wherein a magnetic detecting means (for example, a coil 5) is installed in close proximity between an inner ring and an outer ring of a rolling bearing.
And rotation angle calculating means (for example, arithmetic means 6) for integrating a signal generated in the magnetic detecting means each time the rolling element passes near the magnetic detecting means and converting the signal into a rotation angle of the rotating member. It is characterized by having.

According to the sixth aspect of the present invention, it is possible to provide a rotation angle measuring mechanism for measuring the rotation angle of the rotating member by the method according to the fifth aspect.

According to a further aspect of the present invention, there is provided a rotating speed calculating means (for example, a calculating means 6) for calculating a rotating speed of a rotating member from a rotating angle per unit time. According to the method described in 6, the rotation angle measuring mechanism measures the rotation angle and the rotation speed of the rotating member.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A rolling bearing 1 according to an embodiment of the present invention will be described below in detail with reference to the drawings. 1 is a schematic cross-sectional view of the rolling bearing 1 in the thrust direction (axial direction), FIG. 2 is a schematic cross-sectional view of the rolling bearing 1 in a partially broken radial direction, and FIG. 3 is an enlarged view of a main part of FIG. .

As shown in FIGS. 1 and 2, the rolling bearing 1 has a structure in which a plurality of cylindrical rolling elements 4 are held in a gap between an outer ring 2 and an inner ring 3 so as to be in contact with both wheels. here,
There is no cage between each rolling element 4. For this reason, the weight is reduced as compared with the rolling bearing having the conventional structure.

The outer race 2 is substantially the same as a known outer race.
Although it is made of steel, the inner peripheral surface 21 has a configuration in which an axial end is chamfered to form a tapered surface 21a, and the rolling element contact surface 21b is formed by a flat surface other than the tapered surface 21a.

As shown in FIG. 3, each of the rolling elements 4 is provided with a permanent magnet 4 on an end face of a well-known cylindrical rolling element body 41.
2 is a configuration in which the N pole is attached to the outside. Here, the permanent magnet 42 uses, for example, a rare earth magnet. Also,
The width of the rolling element body 41 is substantially equal to the width of the rolling element contact surface 21b in the thrust direction. Further, the width of the permanent magnet 42 protruding from the end face of the rolling element body 41 is shorter than the width in the thrust direction of the tapered surface 21a. positioned.

In the rolling bearing 1 having such a configuration,
Since the magnetic moments (for example, see arrows in FIG. 3) in each of the rolling elements 4 all point in the same direction, the rolling elements 4 repel each other and independently maintain a substantially uniform interval without using a retainer. I do. When the rolling element 4 is displaced in the thrust direction, an attractive force acts between the permanent magnet 42 and the tapered surface 21a. However, the rolling element 4 is moved to its original position (FIG. 3).
State), the permanent magnet 42 returns to its original position. Therefore, it is not necessary to provide a flange or groove for positioning the rolling element 4 on the inner peripheral surface of the outer race 2 or the outer peripheral surface of the inner race 3.

Accordingly, the rolling bearing 1 has no sliding frictional portions between the cage and the rolling element, and the flange or groove for positioning the rolling element 4. Therefore, the power loss in the rolling bearing 1 is reduced. In addition, wear and iron powder due to wear are less likely to occur, so that the life of the bearing is prolonged as compared with a conventional rolling bearing. Further, the iron powder generated by the abrasion of the rolling element 4 and the outer ring 2 and the inner ring 3 is attracted to the permanent magnet 42, so that the iron powder enters between the rolling element and the outer ring 2 and the inner ring 3 to promote wear. It is hard to happen. Therefore, the life of the rolling bearing 1 is further extended.

Furthermore, since no flange or groove is provided on the inner peripheral surface of the outer race 2 or the outer peripheral surface of the inner race 3, the inner race 3 can be slid in the thrust direction.

The present invention is not limited to the present embodiment, but can be arbitrarily modified without departing from the spirit of the invention. For example, as shown in FIG.
Only one may be provided so as to penetrate the rolling element 4. In this case, the direction of the permanent magnet 42 in each rolling element 4 is made the same. Further, as shown in FIG. 5, the inner ring 3 may be made of steel, and the outer peripheral surface may have the same structure as the inner peripheral surface of the outer ring 2. In this case, the position of the rolling element 4 is harder to shift. Further, as shown in FIG. 6, one of the polarities of the permanent magnets 41 may be reversed from that in FIG.
As shown in (1), the rolling elements 4 themselves may be constituted by permanent magnets.

Further, as shown in FIG. 8, a coil 5 (magnetic detecting means) connected to a calculating means 6 such as a personal computer.
May be provided near the side surface of the rolling bearing 4 so as to be close to between the outer ring 2 and the inner ring 3. The rolling element 4 moves with the rotation of the inner ring 3 or the outer ring 2, and at this time, changes the magnetic flux density in the coil 5. Accordingly, the electromotive force is generated in the coil 5 every time the rolling element 4 passes in the vicinity thereof, so that the pulse voltage change is detected by the calculating means 6 as a pulse signal, and the number thereof is integrated. The rotation angle of the inner ring 3 or the outer ring 2 can be detected by multiplying the accumulated number by a constant indicating the ratio between the number of passages of the rolling bearing and the rotation angle of the inner ring 3. Further, by providing the calculating means 6 with a function of detecting the rotation angle within a unit time, the rotation speed of the inner wheel 3 or the outer wheel 2 can be detected. Therefore, the rotation angle and the rotation speed of the shaft 7 supported by the inner race 3 can be measured. The member supported by the inner ring 3 is fixed,
Even when the member connected to the outer race 2 rotates, the rotation angle and the rotation speed of the member can be measured.

[0026]

As described above, according to the first aspect of the present invention described in the first aspect of the present invention, the structure in which the retainer is omitted makes it possible to reduce the sliding friction in the rolling bearing. Longer life. At the same time, the frictional heat is reduced, so that the temperature rise during rotation is reduced, and the life of the lubricant is extended. Further, power loss between the inner ring and the outer ring is reduced due to the reduction in frictional force. Further, the weight of the rolling bearing is reduced by omitting the cage.

According to the second aspect of the present invention, the structural change of the rolling element can be minimized, the strength of the rolling element can be maintained at the same level as the conventional one, and iron powder is generated due to wear of the rolling element. However, since the iron powder is attracted to the permanent magnets at both ends, the possibility that the rolling element, the outer ring and the inner ring are damaged by the iron powder is reduced, and the rolling bearing has a longer life. Further, according to the configuration of the third aspect, the rolling element can be positioned without providing a flange or a groove for inserting and positioning the rolling element on the outer peripheral surface of the inner ring or the inner peripheral surface of the outer ring. The resulting friction can be further reduced.

According to the second aspect of the present invention, a pulse signal generated in a coil is counted and multiplied by a constant to measure the rotation angle of the rotary member with a simple configuration. be able to. Furthermore, as described in claim 6, the rotation speed of the rotating member can be calculated from the rotation angle per unit time. Further, according to the third invention of the present application described in claims 7 and 8, according to claim 5 or 6,
A mechanism for measuring the rotation angle can be provided by the described method.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view in the thrust direction of a rolling bearing according to an embodiment of the present invention.

FIG. 2 is a schematic sectional view in the same radial direction.

FIG. 3 is an enlarged view of a main part of FIG. 1;

FIG. 4 is a schematic view showing a main part of a modified example of the rolling bearing.

FIG. 5 is a schematic view showing a main part of another modification of the rolling bearing.

FIG. 6 is a schematic view showing a main part of another modification of the rolling bearing.

FIG. 7 is a schematic view showing a main part of another modification of the rolling bearing.

FIG. 8 is a diagram showing a state in which a coil and an arithmetic unit are provided near a rolling bearing.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Rolling bearing 2 Outer ring 3 Inner ring 4 Rolling element 5 Coil (magnetic detection means) 6 Calculation means (rotation angle calculation means and rotation speed calculation means) 21 Inner peripheral surface 21b Roller contact surface 42 Permanent magnet

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) G01P 3/487 G01P 3/487 Z L H02K 5/173 H02K 5/173 A F term (Reference) 2F077 AA44 AA49 JJ06 JJ23 NN04 NN07 NN21 PP06 PP21 TT31 TT71 VV02 3J101 AA13 AA34 AA42 AA52 AA62 BA05 BA10 BA53 BA54 BA70 EA02 EA80 FA31 FA51 GA24 5H605 AA08 BB05 CC04 EB10

Claims (8)

[Claims] In a rolling bearing having a plurality of roller-shaped rolling elements between an inner ring and an outer ring, a permanent magnet is provided on each rolling element so that the direction of a magnetic moment is the same as the rotation axis of the rolling element. Rolling bearings, wherein the repulsive force between the permanent magnets keeps the spacing between the rolling elements. 2. The rolling bearing according to claim 1, wherein permanent magnets are respectively attached to both end faces of the rolling element. 3. The rolling bearing according to claim 1, wherein the rolling element itself is a permanent magnet. 4. The rolling bearing according to claim 1, wherein at least one of the outer peripheral surface of the inner ring and the inner peripheral surface of the outer ring is made of a magnetic material, and the surface is formed of an axial end. A rolling bearing characterized by being chamfered and convex toward a rolling element. 5. A rotation angle measuring method for measuring a rotation angle of a rotating member supported by a rolling bearing according to claim 1, wherein a magnetic field is detected between an inner ring and an outer ring of the rolling bearing. The rotation angle of the rotating member is calculated by disposing the means close to each other, multiplying a constant generated by integrating the signal generated by the magnetic detection means each time the rolling element passes near the magnetic detection means, and calculating the rotation angle of the rotating member. Rotation angle measurement method. 6. The rotation angle measuring method according to claim 5, wherein the rotation speed of the rotating member is calculated from the rotation angle per unit time. 7. A rotation angle measuring mechanism for measuring a rotation angle of a rotating member supported by a rolling bearing according to any one of claims 1 to 4, wherein the rotation angle measuring mechanism is provided between the inner ring and the outer ring of the rolling bearing. A rotation angle calculation unit that integrates a signal generated in the magnetic detection unit every time the rolling element passes near the magnetic detection unit and converts the signal into a rotation angle of the rotation member; A rotation angle measuring mechanism comprising: 8. The rotation angle measuring mechanism according to claim 7, further comprising a rotation speed calculating means for calculating a rotation speed of the rotating member from a rotation angle per unit time.