Magnetic ring unit

Abstract

The present invention is such that a magnetic ring-side peripheral surface portion and a rotor-side peripheral surface portion of a fitting structure between a magnetic ring and a rotor are fitted in an integrally rotatable manner via an interference fit, and deformation of a fitting member undergoing said fitting is suppressed by means of a simple structure. The present invention has: a plurality of interference-fit regions (FA1, FA2) where rotor-side peripheral surface portions (21d-21g) and a magnetic ring-side peripheral surface portion (12a) make contact in the radial direction along the entire periphery thereof; and a gap region (GA) where the two kinds of peripheral surface portions (21d-21g and 12a) radially face each other, without making contact, between the interference-fit regions (FA1, FA2). At least one of the two kinds of peripheral surface portions has a peripheral groove (21f) that forms the gap region (GA), and the two kinds of peripheral surface portions are fitted together with the peripheral groove (21f) remaining empty.

Description

Magnetic Ring Unit

[0001] The present invention relates to a magnetic ring unit in which a magnetic ring of a magnetic rotation sensor is fitted to a rotating body such as a raceway ring or a shaft so as to be rotatable together with the magnetic ring.

[0002] Conventionally, in order to control the rotation of servo motors, joint mechanisms of industrial robots, etc., magnetic rotation sensors have been used to detect the rotational motion of rotating bodies such as rotating shafts such as motor shafts and joint shafts, and the rotating side raceways of rolling bearings that support the rotating shafts.

[0003] To make industrial robots and other machinery smaller and lighter, the components must also be made smaller, and in addition to miniaturizing individual components, integrating them into one another is also effective. One way to achieve this is to integrate the magnetic rotation sensor with the rotating shaft or rolling bearing described above, thereby reducing the space required for installation and the assembly time.

[0004] A magnetic rotation sensor includes a magnetic ring fitted to a rotating body and a magnetic sensor that detects changes in the magnetic field caused by the rotation of the magnetic ring. For example, when a magnetic rotation sensor is integrated with a rolling bearing, the magnetic sensor is attached to one of the inner and outer rings, and the magnetic ring is attached to the other ring opposite the one ring. When the bearing with a rotation sensor is installed in machinery, one ring is a stationary ring that does not rotate, and the other ring is a rotating ring that rotates integrally with the rotating member of the machinery. The magnetic ring has magnets that are magnetized with alternating polarities (north and south poles) in the circumferential direction. The magnetic sensor converts changes in the magnetic field caused by the integral rotation of the other ring and the magnetic ring into an electrical output signal and transmits the generated output signal (see, for example, Patent Document 1).

[0005] The bearing with magnetic rotation sensor disclosed in Patent Document 1 has a magnetic ring composed of a magnet formed in an annular shape from magnetic rubber and a core metal supporting the magnet, and a fitting structure that fits the magnetic ring with an inner ring as a rotating body. The fitting structure consists of a cylindrical circumferential surface portion formed on the inner periphery of the core metal and a cylindrical circumferential surface portion formed on the outer periphery of the inner ring. The inner ring and magnetic ring are fitted together so that they can rotate together.

[0006] Japanese Patent Application Laid-Open No. 2002-326262

[0007] However, the fitting structure between the rotating body and the magnetic ring as disclosed in Patent Document 1 is a structure in which the circumferential surface portion on the rotating body side and the circumferential surface portion on the magnetic ring side are tightly fitted together over the entire area of ​​a specified axial range, so there is room for improvement in that the fitting member having the circumferential surface portion is easily deformed due to the pressure acting on the fitting portion where these circumferential surface portions are in radial contact around the entire circumference.

[0008] For example, in Patent Document 1, the core of a magnetic ring is joined to the outer periphery of the inner ring of a deep groove ball bearing, and the axial fitting length over which the cylindrical circumferential surface of the inner periphery of the core and the cylindrical circumferential surface of the outer periphery of the inner ring overlap radially is greater than half the width of the outer diameter surface of the shoulder of the inner ring, and both circumferential surfaces are continuously interference-fitted along this fitting length. Such a long fitting length can cause deformation of the inner ring or magnetic ring due to unequal diameters of the circumferential surfaces or misalignment when fitting the two circumferential surfaces together, potentially reducing the runout accuracy of the rolling bearing and the magnetic ring after fitting. Furthermore, the longer the fitting length, the greater the press-fitting force required during the fitting process, which increases the likelihood of misalignment and increases the number of work steps required.

[0009] On the other hand, when the peripheral surface of the rotating body and the peripheral surface of the magnetic ring are loosely fitted, it becomes difficult to align the centers of rotation of the two, and it takes time to align the centers of the two peripheral surfaces, and adhesives may be required to ensure the fitting strength of the two, reducing workability. If adhesive is used, the fixing strength of the adhesive may weaken due to vibrations and centrifugal force when the rotating body rotates, and the magnetic ring may fall off, so when rotation detection accuracy is required, it is preferable to use an interference fit between the fitting portion on the rotating body and the fitting portion on the magnetic ring.

[0010] Therefore, the problem that this invention aims to solve is to suppress deformation of the mating parts with a simple structure, while allowing the peripheral surface part on the magnetic ring side and the peripheral surface part on the rotating body side of the mating structure between the magnetic ring and the rotating body to be mated together and rotate integrally with an interference fit.

[0011] In order to solve the above problems, the present invention provides a magnetic ring unit comprising: a magnet and a core supporting the magnet; a rotor that rotates in the circumferential direction of the magnetic ring; and a fitting structure that fits the core and the rotor, the fitting structure having a circumferential surface portion on the rotor side and a circumferential surface portion on the magnetic ring side that are opposed to each other in the radial direction, the circumferential surface portion on the rotor side and the circumferential surface portion on the magnetic ring side being fitted together so as to be able to rotate integrally by means of an interference fit between the circumferential surface portion on the rotor side and the circumferential surface portion on the magnetic ring side. and a gap region where the circumferential surface portion on the rotating body side and the circumferential surface portion on the magnetic ring side face each other radially without contacting each other between the two interference fit regions, and at least one of the circumferential surface portion on the rotating body side and the circumferential surface portion on the magnetic ring side has a circumferential groove that forms the gap region, and the circumferential surface portion on the rotating body side and the circumferential surface portion on the magnetic ring side are fitted together while the inside of at least one of the circumferential grooves is empty.

[0012] According to the above-mentioned configuration 1, the gap region where the circumferential surface portion of the rotor side and the circumferential surface portion of the magnetic ring side face each other in a non-contact manner in the radial direction is provided by the circumferential groove, so that the press-fitting force required when fitting the two circumferential surface portions together is reduced, misalignment is less likely to occur, and deformation due to fitting of the two circumferential surface portions can be suppressed. Furthermore, the gap region can be a simple structure in which a circumferential groove is formed on at least one of the circumferential surface portion of the rotor side and the circumferential surface portion of the magnetic ring side, and the two circumferential surface portions are fitted together in an empty state without placing anything in each circumferential groove.

[0013] In the above configuration 1, a configuration 2 can be adopted in which the rolling bearing includes an inner ring, an outer ring, and a plurality of rolling elements arranged between the inner ring and the outer ring, the rotating element consists of one of the raceways of the inner ring and the outer ring, the circumferential surface portion on the rotating element side is formed on one end-side circumferential surface that is continuous with the raceway surface and one end face of the one raceway ring, and the circumferential groove is formed on the side of the one end-side circumferential surface that is closer to the one end face. According to this configuration 2, the raceway ring of the rolling bearing is used as the rotating element, and the one end-side circumferential surface between this raceway surface and the one end face is used to form the circumferential surface portion on the rotating element side, while preventing interference between the rolling elements and a member having a circumferential surface on the magnetic ring side that is fitted thereto, and suppressing deformation of the raceway surface.

[0014] For example, in the above configuration 1 or 2, configuration 3 can be adopted in which the rotating body is made of a raceway ring, which is a component of a rolling bearing, and the fitting structure is made of a peripheral surface portion on the rotating body side formed on the rotating body and a peripheral surface portion on the magnetic ring side formed on the core metal.

[0015] Furthermore, in the above configuration 1 or 2, configuration 4 can also be adopted, in which the fitting structure has the rotating body, the core bar, and a ring member connecting the rotating body and the core bar, and the fitting structure includes at least one fitting portion selected from a first fitting portion consisting of a peripheral surface portion on the rotating body side formed on the rotating body and a peripheral surface portion on the magnetic ring side formed on the ring member, and a second fitting portion consisting of a peripheral surface portion on the rotating body side formed on the ring member and a peripheral surface portion on the magnetic ring side formed on the core bar.

[0016] In any one of the above configurations 1 to 4, a configuration 5 can be adopted in which the circumferential surface portion on the rotating body side and the circumferential surface portion on the magnetic ring side each have the circumferential groove. According to this configuration 5, the circumferential groove on the circumferential surface portion on the rotating body side and the circumferential groove on the circumferential surface portion on the magnetic ring side can be combined to more flexibly provide the gap region.

[0017] In any one of the above configurations 1 to 5, a configuration 6 can be adopted in which, of all the interference-fit regions where the circumferential surface portion of the rotor side and the circumferential surface portion of the magnetic ring side are in radial contact, the total length of all the gap regions within the axial length W is set to be 0.1 W or more and 0.8 W or less, where W is the axial length between a first end located furthest on one axial side and a second end located furthest on the other axial side. If the total length of all the gap regions within the axial length W is 0.1 W or more, the effect of suppressing deformation due to the gap regions can be obtained, but if it exceeds 0.8 W, there is a concern that the fit between the circumferential surface portion of the rotor side and the circumferential surface portion of the magnetic ring side may deteriorate or the fitting force may decrease after they are fitted together.

[0018] As described above, by adopting the above configuration 1, this invention can suppress deformation of the mating members with a simple structure, while allowing the peripheral surface portion on the magnetic ring side and the peripheral surface portion on the rotating body side of the mating structure between the magnetic ring and the rotating body to be mated together and rotate integrally with an interference fit.

[0019] A cross-sectional view showing a magnetic ring unit according to a first embodiment of the present invention. A cross-sectional view showing a main part of a magnetic ring unit according to a second embodiment of the present invention. A cross-sectional view showing a main part of a magnetic ring unit according to a third embodiment of the present invention. A cross-sectional view showing a main part of a magnetic ring unit according to a fourth embodiment of the present invention. A cross-sectional view showing a main part of a magnetic ring unit according to a fifth embodiment of the present invention. A cross-sectional view showing a main part of a magnetic ring unit according to a sixth embodiment of the present invention.

[0020] A magnetic ring unit according to a first embodiment of the present invention will be described with reference to FIG. 1 of the accompanying drawings.

[0021] The magnetic ring unit shown in FIG. 1 (hereinafter referred to as “this magnetic ring unit”) is configured as a bearing with a magnetic rotation sensor, which includes a magnetic ring 10, a rolling bearing 20, and a sensor ring 30.

[0022] The magnetic ring 10 comprises a magnet 11 and a core metal 12 that supports the magnet 11 .

[0023] The magnet 11 has the cross-sectional shape shown in the figure and is formed in a circular ring shape that goes around the central axis of the magnetic ring 10 (not shown). Hereinafter, the direction along the central axis of the magnetic ring 10 will be referred to as the "axial direction," the direction perpendicular to the central axis will be referred to as the "radial direction," and the circumferential direction that goes around the central axis will be referred to as the "circumferential direction." In the figure, the central axis of the magnetic ring 10 coincides with the bearing center axis of the rolling bearing 20, and the axial direction corresponds to the left-right direction in the figure, and the radial direction corresponds to the up-down direction in the figure.

[0024] The magnet 11 is a permanent magnet that is magnetized with alternate polarities in the circumferential direction. A magnetic material such as a rubber magnet or a plastic magnet is generally used as the magnet 11. The number of magnetization tracks of the magnet 11 may be a single row or multiple rows.

[0025] The core 12 is an annular member that radially supports the inner peripheral surface of the magnet 11. The core 12 has the cross-sectional shape shown in the figure and is continuous around the entire circumference. The core 12 is formed from a single metal plate. A magnetic material such as a mild steel plate is used as the metal plate. A pressed part is generally used as the core 12.

[0026] The inner peripheral surface of the magnet 11 is bonded to the outer peripheral surface of the core metal 12 .

[0027] The rolling bearing 20 has an inner ring 21 as one of the raceways constituting the rotating body that rotates in the circumferential direction of the magnetic ring 10, an outer ring 22, a plurality of rolling elements 23 arranged between the inner ring 21 and the outer ring 22, and a retainer 24 that holds these rolling elements 23.

[0028] The inner ring 21 and the outer ring 22 are each a single seamless raceway ring, and are each made of metal such as bearing steel.

[0029] Although a deep groove ball bearing is exemplified as the rolling bearing 20, any type of rolling bearing may be used, and it may be changed to an angular contact ball bearing, a roller bearing, or the like.

[0030] The inner ring 21 is a rotating ring. The inner ring 21 is attached to a rotating shaft (not shown) of machinery so as to be rotatable together with the rotating shaft. The rotating shaft is, for example, a joint shaft of a robot arm or the like, or a motor shaft of a servo motor. The outer ring 22 is a stationary ring. The outer ring 22 is attached to, for example, a housing (not shown) of the machinery.

[0031] The magnetic ring 10 is fixed in a state in which it can rotate integrally with the inner ring 21 in the circumferential direction with a predetermined degree of coaxiality by a fitting structure that fits the core metal 12 and the inner ring 21. The inner ring 21 becomes a rotating body that rotates in the circumferential direction by being attached to the rotating shaft of machinery as described above.

[0032] The sensor ring 30 has a magnetic sensor element 31, a circuit board 32, and an annular holder 33 that holds the magnetic sensor element 31 and the circuit board 32. The annular holder 33 is fixed to the outer ring 22 by being press-fitted into the outer ring 22. The sensor circuit board that has the magnetic sensor element 31 and the circuit board 32 is an electric circuit that converts changes in the magnetic field that accompany the circumferential rotation of the magnet 11 relative to the magnetic sensor element 31 into a predetermined output signal and sends it to the outside. The output signal is an electric signal that indicates a physical quantity corresponding to the circumferential rotational motion of the magnet 11, and examples of such signals include an absolute rotation angle signal and a rotational speed signal.

[0033] The inner ring 21, which is a rotating body that rotates in the circumferential direction and is one of the raceways that is a component of the rolling bearing 20, has a raceway surface 21a, one end face 21b located on one of the two ends that defines the width of the inner ring 21, and one end side peripheral surface 21c that continues from the raceway surface 21a to the one end face 21b.

[0034] The fitting structure that fits the core metal 12 and the inner ring 21 comprises a magnetic ring-side peripheral surface portion 12a formed on the inner circumference of the core metal 12, and inner ring-side peripheral surface portions (21d to 21g) formed on one end side peripheral surface 21c of the inner ring 21. The magnetic ring-side peripheral surface portion 12a has a cylindrical surface shape that extends in the entire circumferential direction.

[0035] One end face 21b of the inner ring 21 is flat along the radial direction. The circumferential surface portion on the inner ring side is composed of a chamfered portion 21d continuing to the one end face 21b, a first cylindrical surface portion 21e continuing to the chamfered portion 21d on the raceway surface 21a side, a circumferential groove 21f continuing to the first cylindrical surface portion 21e on the raceway surface 21a side, and a second cylindrical surface portion 21g continuing to the circumferential groove 21f on the raceway surface 21a side.

[0036] The first cylindrical surface portion 21e and the second cylindrical surface portion 21g are cylindrical surfaces having the same diameter. The diameter of the peripheral surface portion 12a on the magnetic ring side has a radial interference with the diameters of the first cylindrical surface portion 21e and the second cylindrical surface portion 21g.

[0037] The circumferential groove 21f consists of a groove portion that runs around the first cylindrical surface portion 21e and the second cylindrical surface portion 21g in the circumferential direction with a groove depth in the radial direction, and extends around the entire circumferential direction with the cross-sectional shape shown in the figure.

[0038] The circumferential groove 21f is formed on the one-end peripheral surface 21c of the inner ring 21, closer to the one end surface 21b. In other words, the groove center position that bisects the groove width of the circumferential groove 21f in the axial direction is closer to the one end surface 21b than the position that bisects the width of the one-end peripheral surface 21c in the axial direction.

[0039] The process of fitting together the circumferential surface portion 12a on the magnetic ring side and the circumferential surface portions (21d-21g) on ​​the rotating body side is performed by coaxially arranging the magnetic ring 10 and the inner ring 21 and bringing the magnetic ring 10 and the inner ring 21 closer to each other in the axial direction while the circumferential groove 21f is empty. Here, the empty state of the circumferential groove 21f refers to a state in which the space inside the circumferential groove 21f, which is recessed radially relative to the first and second cylindrical surface portions 21e and 21g, is free of solid or semi-solid materials such as O-rings, gaskets, grease, adhesives, etc.; for example, adhesives or pressure-sensitive adhesives intended for sealing, bonding, or strengthening fixation are not filled into the circumferential groove 21f.

[0040] During the fitting process, the circumferential surface portion 12a on the magnetic ring side first comes into contact with the chamfered portion 21d of the inner ring 21. Then, due to the axial press-fit force applied to the core metal 12, the circumferential surface portion 12a on the magnetic ring side slides along the chamfered portion 21d and deforms to have the same diameter as the first cylindrical surface portion 21e. After passing the first cylindrical surface portion 21e, the circumferential surface portion 12a straddles the circumferential groove 21f and reaches the second cylindrical surface portion 21g. This results in two interference fit regions FA1, FA2 where the first and second cylindrical surface portions 21e, 21g of the circumferential surface portion (21d to 21g) on ​​the rotating body side and the circumferential surface portion 12a on the magnetic ring side are in radial contact around the entire circumference, a gap region GA where the circumferential groove 21f of the circumferential surface portion (21d to 21g) on ​​the rotating body side and the circumferential surface portion 12a on the magnetic ring side face each other in a non-contacting manner around the entire circumference, and a gap region where the chamfered portion 21d of the circumferential surface portion (21d to 21g) on ​​the rotating body side and the circumferential surface portion 12a on the magnetic ring side face each other in a non-contacting manner around the entire circumference.

[0041] The peripheral surface portions (21d to 21g) on ​​the rotating body side and the peripheral surface portion 12a on the magnetic ring side are tightly fitted together in two interference fit areas FA1 and FA2 so as to be able to rotate together.

[0042] Here, of all the interference fit regions FA1, FA2 where the rotor-side circumferential surface portions (21d-21g) and the magnetic ring-side circumferential surface portion 12a are in radial contact, the axial length between the first end P1 located closest to one axial side and the second end P2 located closest to the other axial side is defined as W. The axial fit length where the rotor-side circumferential surface portions (21d-21g) and the magnetic ring-side circumferential surface portion 12a face each other in the radial direction corresponds to the sum of the axial length W and the width of the chamfered portion 21d. Within the range of the axial length W, the only gap region where the rotor-side circumferential surface portions (21d-21g) and the magnetic ring-side circumferential surface portion 12a face each other in a non-contact manner in the radial direction over the entire circumference is a single gap region GA defined by the circumferential groove 21f.

[0043] As described above, when the fitting process is performed, there is no friction between the magnetic ring-side peripheral surface portion 12a and the circumferential groove 21f, so the press-fit force required to press the magnetic ring-side peripheral surface portion 12a into the second cylindrical surface portion 21g is smaller than when the same cylindrical surface is formed from the first cylindrical surface portion 21e to the second cylindrical surface portion 21g over the entire axial length W without providing the circumferential groove 21f. Furthermore, because the circumferential groove 21f has a constant cross-sectional shape all around, when the magnetic ring-side peripheral surface portion 12a straddles the circumferential groove 21f, the pressure distribution between the magnetic ring-side peripheral surface portion 12a and the first and second cylindrical surface portions 21e, 21g becomes uneven in the circumferential direction, which prevents the central axis of the magnetic ring-side peripheral surface portion 12a (magnetic ring 10) from tilting relative to the central axis of the inner ring 21. Therefore, since the gap area GA is provided by the circumferential groove 21f, the press-fitting force required during the fitting process is reduced, misalignment is less likely to occur, and deformation of the inner ring 21 and magnetic ring 10 due to the fitting is suppressed.

[0044] The total length of all gap regions within the axial length W is preferably set to be 0.1W or more and 0.8W or less. This total length corresponds to the axial length of the gap region GA that exists in only one location within the axial length W, and corresponds to the groove width of the circumferential groove 21f that forms this gap region GA. If the total length of all gap regions within the axial length W is 0.1W or more, the effect of suppressing press-fitting force and misalignment can be obtained, but if it exceeds 0.8W, the total length of the interference fit regions FA1, FA2 within the axial length W becomes shorter, which raises concerns about a deterioration in the settling (stability) of the magnetic ring 10 relative to the inner ring 21 after fitting and a decrease in fitting force.

[0045] It is possible to reduce the press-fit force by, for example, shortening the width of the circumferential surface portion 12a on the magnetic ring side and shortening the axial length W without providing the gap region GA by the circumferential groove 21f, but doing so raises concerns that the posture of the magnetic ring 10 relative to the inner ring 21 will be less stable, making misalignment more likely to occur. For this reason, it is preferable to form a gap region GA by the circumferential groove 21f that faces each other in a non-contact manner in the radial direction over the entire circumference between multiple interference-fit regions FA1, FA2 where the circumferential surface portions (21d to 21g) on ​​the rotating body side and the circumferential surface portion 12a on the magnetic ring side are in radial contact over the entire circumference, thereby reducing the total length of the interference-fit regions in the axial length W without shortening the axial length W and thereby reducing the press-fit force.

[0046] As described above, this magnetic ring unit comprises a magnetic ring 10 having a magnet 11 and a core 12 supporting the magnet 11, an inner ring 21 as a rotating body that rotates in the circumferential direction of the magnetic ring 10, and an engagement structure that engages the core 12 and the inner ring 21 as a rotating body, and the engagement structure has a peripheral surface portion (21d to 21g) on ​​the rotating body side and a peripheral surface portion 12a on the magnetic ring side that face each other radially, and the peripheral surface portion (21d to 21g) on ​​the rotating body side and the peripheral surface portion 12a on the magnetic ring side are engaged with each other by a tight fit so that they can rotate together.

[0047] This magnetic ring unit has, in particular, a plurality of interference fit regions FA1, FA2 where the circumferential surface portion (21d to 21g) on ​​the rotating body side and the circumferential surface portion 12a on the magnetic ring side are in contact in the radial direction over the entire circumference, and a gap region GA where the circumferential surface portion (21d to 21g) on ​​the rotating body side and the circumferential surface portion 12a on the magnetic ring side face each other in a non-contact manner in the radial direction between the interference fit regions FA1, FA2, and the circumferential surface portion (21d to 21g) on ​​the rotating body side and the circumferential surface portion 12a on the magnetic ring side have a circumferential groove 21f that forms the gap region GA, and the circumferential groove 21 Since the circumferential surface portion (21d-21g) on ​​the rotor side and the circumferential surface portion 12a on the magnetic ring side are fitted together while the inside of groove 21f is empty, a gap area GA is provided by circumferential groove 21f, where the circumferential surface portion (21d-21g) on ​​the rotor side and the circumferential surface portion 12a on the magnetic ring side face each other in a non-contact manner in the radial direction around the entire circumference, which reduces the press-fitting force required when fitting together the two circumferential surface portions (21d-21g, 12a), making it less likely that misalignment will occur, and suppressing deformation of the inner ring 21 and magnetic ring 10 due to the fitting together of the two circumferential surface portions (21d-21g, 12a). Furthermore, the gap area GA can be formed in a simple structure by forming circumferential groove 21f on the circumferential surface portion (21d-21g) on ​​the rotor side and fitting together the two circumferential surface portions (21d-21g, 12a) in an empty state without placing anything in circumferential groove 21f.

[0048] Therefore, this magnetic ring unit has a fitting structure between the magnetic ring 10 and the inner ring 21 as a rotating body, in which the peripheral surface portion 12a on the magnetic ring side and the peripheral surface portion (21d to 21g) on ​​the rotating body side are fitted together so that they can rotate together, while at the same time, deformation of the fitting members, the magnetic ring 10 and inner ring 21, can be suppressed with a simple structure.

[0049] The magnetic ring unit also includes a rolling bearing 20 having an inner ring 21, an outer ring 22, and a plurality of rolling elements 23 arranged between the inner ring 21 and the outer ring 22, and the rolling element is the inner ring 21 as one of the raceways of the inner ring 21 and the outer ring 22. The circumferential surface portion (21d to 21g) on ​​the rolling element side is formed on a one-end circumferential surface 21c that is continuous between the raceway surface 21a and one end surface 21b of the inner ring 21 as one of the raceways. A circumferential groove 21f is formed on the one-end circumferential surface 21c on the side closer to the one end surface 21b, thereby allowing the rolling element to move smoothly. The inner ring 21 as the raceway ring of the bearing 20 is used as a rotating body, and one end side peripheral surface 21c between this raceway surface 21a and one end face 21b is used to form the peripheral surface portion (21d to 21g) on ​​the rotating body side, and there is no need to press the peripheral surface portion 12a of the magnetic ring side that is fitted here deep into the raceway surface 21a, thereby reducing the fitting length of both peripheral surface portions (21d to 21g, 12a). This makes it possible to prevent interference between the core metal 12 as a member having the peripheral surface portion 12a on the magnetic ring side and the rolling elements 23 and the retainer 24, and suppress deformation of the raceway surface 21a.

[0050] Furthermore, in this magnetic ring unit, the rotating body is made up of an inner ring 21 as a raceway ring, which is a component of the rolling bearing 20, and the fitting structure is made up of a rotating body side peripheral surface portion (21d to 21g) formed on the inner ring 21 as the rotating body and a magnetic ring side peripheral surface portion 12a formed on the core 12, thereby achieving a simple fitting structure utilizing the inner ring 21 as a raceway ring and the core 12, while suppressing deformation due to fitting of the inner ring 21 as a raceway ring and the magnetic ring 10.

[0051] Furthermore, in this magnetic ring unit, when the axial length between the first end P1 located furthest on one axial side and the second end P2 located furthest on the other axial side is defined as W, of all the press-fit areas FA1, FA2 where the circumferential surface portion (21d to 21g) on ​​the rotating body side and the circumferential surface portion 12a on the magnetic ring side are in radial contact, the total length of all the gap areas GA that occupy the axial length W is set to be 0.1W or more and 0.8W or less.This allows the gap areas GA to achieve the effect of suppressing deformation of the magnetic ring 10, etc., while reducing the concern that the fit of the circumferential surface portion (21d to 21g) on ​​the rotating body side and the circumferential surface portion 12a on the magnetic ring side will deteriorate or the fitting force will decrease after they are fitted together.

[0052] In the first embodiment, an example was shown in which the circumferential groove 21f was formed on the inner ring 21 as the rotating body, but it is also possible to form the circumferential groove on the circumferential surface of the magnetic ring. Furthermore, the cross-sectional shape of the circumferential groove is not particularly limited, and other cross-sectional shapes are also possible. An example of a second embodiment is shown in FIG. 2. The following description will focus on the differences from the first embodiment.

[0053] The magnetic ring 40 according to the second embodiment includes a core 42 that supports a magnet 41 in the axial direction. The circumferential surface 51 on the rotating body side formed on the inner ring 50 consists of a single cylindrical surface. The circumferential surface on the magnetic ring side formed on the core 42 consists of two cylindrical surface portions 42a, 42b with the same diameter and a circumferential groove 42c that is recessed radially between these cylindrical surface portions 42a, 42b. The cross-sectional shape of the circumferential groove 42c is arc-shaped. The core 42 has a flange surface 42d that supports the magnet 41 in the axial direction.

[0054] In the magnetic ring unit according to the second embodiment, it is only necessary to form the circumferential groove 42c when pressing the core metal 42, and it is not necessary to turn the circumferential groove in the inner ring 50.

[0055] It is also possible to form circumferential grooves on both the circumferential surface of the magnetic ring and the circumferential surface of the rotor, as in a third embodiment shown in FIG.

[0056] The third embodiment differs from the second embodiment in that a circumferential groove is added to the circumferential surface portion on the rotor side. The circumferential surface portion formed on the inner ring 60 on the rotor side consists of two cylindrical surface portions 61, 62 with the same diameter and a circumferential groove 63 recessed radially between these cylindrical surface portions 61, 62. The circumferential groove 63 of the inner ring 60 does not radially face the circumferential groove 42c of the core 42, but faces the cylindrical surface portion 42b on one end side. Therefore, within the axial length W, a first gap area GA1 formed by the circumferential groove 42c of the core 42 and a second gap area GA2 formed by the circumferential groove 63 of the inner ring 60 exist. The total length of all gap areas GA1 and GA2 within the axial length W is approximately twice that of the first and second embodiments. There are press processing limitations on the axial position, groove width, and groove depth at which a circumferential groove can be formed in the core metal 42, but by forming a circumferential groove 63 in the inner ring 60 as well, it becomes possible to flexibly set the total length of the gap areas GA1 and GA2 while restricting the groove width and groove depth of each circumferential groove 63, 42c.

[0057] In the magnetic ring unit of the third embodiment, the circumferential surface portions (61 to 63) on the rotating body side and the circumferential surface portions (42a to 42c) on the magnetic ring side each have circumferential grooves 63, 42c, and by combining the circumferential groove 63 on the circumferential surface portions (61 to 63) on the rotating body side with the circumferential groove 42c on the circumferential surface portions (42a to 42c) on the magnetic ring side, the gap regions GA1, GA2 can be more flexibly provided.

[0058] The magnetic ring may also serve as a component of the sealing device, as shown in FIG.

[0059] The magnetic ring unit according to the fourth embodiment is a sealing device formed by a magnetic ring 80 fixed to an inner ring 70 (a rotating body) and a contact seal 100 fixed to an outer ring 90. A circumferential groove 70c between two cylindrical surface portions 70a, 70b on the rotating body-side peripheral surface has a tapered groove bottom that becomes shallower toward the other axial side. The magnetic ring 80 has a core 82 that supports a magnet 81 in the axial direction. The magnetic ring-side peripheral surface portion 82a is composed of a single cylindrical surface portion and does not have a circumferential groove. A cylindrical seal surface 82b is formed on the side of the core 82 opposite the magnetic ring-side peripheral surface portion 82a, with which a seal lip 101 of a contact seal 100 slides in circumferential contact. Furthermore, a side surface 82c of the core 82 opposite the magnet 81 is in circumferential sliding contact with a side lip 102 of the contact seal 100.

[0060] In the first to fourth embodiments described above, examples were shown in which the fitting structure was formed by the rotating body and the core metal of the magnetic ring, but if the diameter of the rotating body does not match the diameter of the magnet or the like of the magnetic ring, it is also possible to change to a fitting structure in which the rotating body and the magnetic ring are fitted together via a ring member for adjusting the diameter. As an example, a fifth embodiment is shown in Figure 5.

[0061] The magnetic ring 110 according to the fifth embodiment has a simple cylindrical core 112 that radially supports the magnet 111. The inner ring 120, which serves as a rotating body, has a circumferential groove 121 that extends around the entire circumference. The fitting structure that fits the magnetic ring 110 and the inner ring 120 together consists of the inner ring 120, which serves as a rotating body, the core 112, and a ring member 130 that connects the inner ring 120 and the core 112.

[0062] The first fitting portion, which fits the inner ring 120 and the ring member 130 together so that they can rotate together in the circumferential direction, utilizes a locking structure in which the circumferential groove 121 of the inner ring 120 prevents the protrusion 131 of the ring member 130 from coming off in the axial direction. For example, the inner ring 120 may have a seal groove that cooperates with a seal member (not shown) on the outer ring side to provide a sealing effect, and this seal groove may be used as the circumferential groove 121. The protrusion 131 of the ring member 130 is elastically fitted into the circumferential groove 121 of the inner ring 120. Therefore, the areas near the protrusion 131 of the inner ring 120 and the ring member 130 are fitted together to the extent that they can rotate together in the circumferential direction due to frictional contact between the areas near the protrusion 131 and the inner ring 120, and deformation of the inner ring 120 and the ring member 130 due to this fitting is small.

[0063] On the other hand, the second fitting portion, which fits together the ring member 130 and the core metal 112 so that they can rotate together in the circumferential direction, is made up of a circumferential surface portion (132-134) on the rotating body side formed on the ring member 130 and a circumferential surface portion 112a on the magnetic ring side formed on the core metal 112. The circumferential surface portion (132-134) on the rotating body side is made up of two cylindrical surface portions 132, 133 having the same diameter, and a circumferential groove 134 formed between these cylindrical surface portions 132, 133. The ring member 130 may be a pressed part or a resin-molded part.

[0064] The magnetic ring unit according to the fifth embodiment can suppress deformation of the ring member 130 and the magnetic ring 110 during the fitting process of fitting the diameter-adjusting ring member 130 and the magnetic ring 110 together.

[0065] In the fifth embodiment, an example was given of an engagement structure in which the protrusion 131 of the ring member 130 is inserted into the circumferential groove 121 of the inner ring 120 by utilizing the elastic deformation of the protrusion 131. However, if the ring member is made of a metal plate, it is also possible to adopt an engagement structure in which a metal plate portion formed around the entire circumference or at multiple points in the circumferential direction is crimped and brought into contact with the inside of the circumferential groove 121.

[0066] In the fifth embodiment, the first fitting portion that fits the inner ring 120 and the ring member 130 has a locking structure, but the first fitting portion can also be changed to a fitting structure that fits with a plurality of interference fit regions. An example of such a sixth embodiment is shown in Figure 6. The sixth embodiment is a further modification of the fifth embodiment.

[0067] The second fitting portion for fitting the ring member 140 and magnetic ring 110 according to the sixth embodiment is similar to that of the fifth embodiment, except that the protrusions on the ring member 140 are omitted, and the inner ring 150 serving as the rotating body is also formed with a rotating body-side circumferential surface portion for the first fitting portion, which is composed of two cylindrical surface portions 151 and 152 having the same diameter and a circumferential groove 153 recessed radially between these cylindrical surface portions 151 and 152. The ring member 140 is formed with a single cylindrical surface portion constituting the magnetic ring-side circumferential surface portion 141 for the first fitting portion. The magnetic ring unit according to the sixth embodiment can suppress deformation of the ring member 140 and the inner ring 150 during the fitting process of fitting the inner ring 150 with the diameter-adjusting ring member 140, and can also suppress deformation of the ring member 140 and the magnetic ring 110 during the fitting process of fitting the ring member 140 and the magnetic ring 110.

[0068] In addition, in the fifth and sixth embodiments, it is also possible to form a circumferential groove in the core metal of the magnetic ring as in the second embodiment, or to form a circumferential groove in both the core metal of the magnetic ring and the ring member as in the third embodiment.

[0069] In the first to sixth embodiments described above, an example was shown in which the inner ring, which is one of the inner and outer raceways of the rolling bearing, is used as the rotating body, but if the outer ring is used as the rotating ring, it is also possible to use the outer ring as the rotating body.In this case, by similarly providing a gap area using a circumferential groove in the fitting structure in which the outer ring and the core metal of the magnetic ring are fitted together, deformation of the outer ring, magnetic ring, etc. can be suppressed.

[0070] Furthermore, in the first to sixth embodiments described above, examples have been shown in which the raceway ring of a rolling bearing is used as the rotating body, but it is also possible to use the rotating shaft of machinery as the rotating body. In this case, if a gap region formed by a circumferential groove is similarly provided in the fitting structure that fits the rotating shaft and the core metal of the magnetic ring, deformation of the magnetic ring, etc. can be suppressed.

[0071] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims.

[0072] 10, 40, 80, 110 Magnetic ring 11, 41, 81, 111 Magnet 12, 42, 82, 112 Core metal 12a, 82a, 112a, 141 Circumferential surface portion on magnetic ring side 20 Rolling bearing 21, 50, 60, 70, 120, 150 Inner ring (rotating body) 21a Raceway surface 21b One end face 21c One end side circumferential surface 21d Chamfered portion 21e, 21g, 42a, 42b, 61, 62, 70a, 70b, 132, 133, 151, 152 Cylindrical surface portion 21f, 42c, 63, 70c, 134, 153 Circumferential groove 22, 90 Outer ring 23 Rolling element 51 Circumferential surface portion on rotating body side 121 Circumferential groove 130, 140 Ring member 131 Projection portion FA1, FA2 Interference fit area GA, GA1, GA2 Gap area P1 First end P2 Second end W Axial length

Claims

1. A magnetic ring unit comprising: a magnetic ring having a magnet and a core supporting the magnet; a rotating body that rotates in the circumferential direction of the magnetic ring; and a fitting structure that fits the core and the rotating body, wherein the fitting structure has a rotating body-side peripheral surface portion and a magnetic ring-side peripheral surface portion that face each other in the radial direction, and the rotating body-side peripheral surface portion and the magnetic ring-side peripheral surface portion are fitted together by an interference fit so that they can rotate together; the magnetic ring unit has a plurality of interference fit regions where the rotating body-side peripheral surface portion and the magnetic ring-side peripheral surface portion are in radial contact around the entire circumference, and gap regions where the rotating body-side peripheral surface portion and the magnetic ring-side peripheral surface portion face each other in a non-contact manner in the radial direction between the interference fit regions, at least one of the rotating body-side peripheral surface portion and the magnetic ring-side peripheral surface portion has a circumferential groove that forms the gap region, and the rotating body-side peripheral surface portion and the magnetic ring-side peripheral surface portion are fitted together with at least one of the circumferential grooves being empty.

2. A magnetic ring unit as described in claim 1, comprising a rolling bearing having an inner ring, an outer ring, and a plurality of rolling elements arranged between the inner ring and the outer ring, wherein the rotating element is one of the raceways of the inner ring and the outer ring, the circumferential surface portion on the rotating element side is formed on a one end side circumferential surface that is continuous between the raceway surface of the one raceway and one end face, and the circumferential groove is formed on the side of the one end side circumferential surface that is closer to the one end face.

3. A magnetic ring unit as described in claim 1 or 2, wherein the rotating body is made of a raceway ring which is a component of a rolling bearing, and the fitting structure is made of a peripheral surface portion on the rotating body side formed on the rotating body and a peripheral surface portion on the magnetic ring side formed on the core metal.

4. A magnetic ring unit as described in claim 1 or 2, wherein the fitting structure has the rotating body, the core bar, and a ring member connecting the rotating body and the core bar, and the fitting structure includes at least one fitting portion selected from the group consisting of a first fitting portion consisting of a peripheral surface portion formed on the rotating body on the rotating body side and a peripheral surface portion formed on the ring member on the magnetic ring side, and a second fitting portion consisting of a peripheral surface portion formed on the ring member on the rotating body side and a peripheral surface portion formed on the core bar on the magnetic ring side.

5. A magnetic ring unit according to claim 1 or 2, wherein the circumferential surface portion on the rotating body side and the circumferential surface portion on the magnetic ring side each have the circumferential groove.

6. A magnetic ring unit as described in claim 1 or 2, wherein, of all the press-fit areas where the peripheral surface portion on the rotating body side and the peripheral surface portion on the magnetic ring side are in radial contact, when the axial length between the first end located closest to one axial side and the second end located closest to the other axial side is W, the total length of all the gap areas within the axial length W is set to be 0.1W or more and 0.8W or less.

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