Determination device

Abstract

A probe is provided with a probe body that comes into contact with a measurement target surface of a bearing and detects an impedance of the bearing, and a housing that includes a hole in which the probe body is accommodated and has a substantially cylindrical shape. A switch is attachable to and detachable from the housing.

Description

Judgment device

[0001] The present invention relates to a determination device.

[0002] For example, rolling bearings used in papermaking machines, wind power generation equipment, mining and construction equipment, and railway vehicles are subject to heavy loads and harsh lubrication conditions that expose them to the intrusion of foreign objects and water, making flaking on the bearing raceway a problem. Flaking on rolling bearings not only has the potential to cause significant damage to products and equipment, but it also impacts manufacturing delivery dates and schedules. To prevent sudden flaking, rolling bearings are sometimes periodically disassembled and cleaned, and visual inspections of the raceway surface are conducted. However, predicting the remaining life of a bearing based on visual inspection (estimating the period until flaking occurs) relies on the experience and skill of the operator, making quantitative predictions difficult.

[0003] In response to this, Patent Document 1 discloses an eddy current flaw detector that uses electromagnetic induction to detect defects occurring in a conductive test object such as a metal material. In the eddy current flaw detector of Patent Document 1, a probe is scanned while being maintained at a constant angle and distance relative to the test object. The angle and distance of the probe relative to the test object are maintained by a probe operating unit shown in Figures 2 to 4 of Patent Document 1. This probe operating unit is composed of various parts such as a grip, a shaft, a collar, a bolt, a rotary lock nut, a roller, a momentary switch, and an encoder.

[0004] Japanese Patent Application Publication No. 2005-201778

[0005] As described above, in Patent Document 1, the probe operation unit including a momentary switch and the like is integrated into the probe, which results in a large probe. Therefore, when inserting the probe into a gap in an object to be measured, a large probe with an integrated switch and the like as in Patent Document 1 may not be applicable. On the other hand, there may be situations where it is easier to perform measurement by attaching a switch to the probe and operating the switch with the hand holding the probe.

[0006] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a determination device that is easy to operate and in which a switch can be attached or detached from a probe depending on the situation.

[0007] Therefore, the above object of the present invention is achieved by the following configuration [1]. [1] A determination device comprising: a probe that applies an AC magnetic field to induce eddy currents in a bearing and detects the impedance of the bearing; a switch that transmits a measurement control signal that switches between starting and stopping the acquisition of a measurement signal of the impedance detected by the probe; and a fatigue determination unit that determines the fatigue level or remaining life of the bearing based on the impedance of the bearing, wherein the fatigue determination unit comprises: a map storage unit that stores a determination map including the relationship between the impedance characteristics of the bearing and the fatigue level or remaining life of the bearing; a measurement switching unit that switches between a measurement execution state and a measurement non-execution state based on the state of the measurement control signal; a data storage unit that stores the measurement signals in the measurement execution state; an impedance characteristic calculation unit that calculates the impedance characteristics of the bearing based on the stored measurement signals; and a determination unit that determines the fatigue level or remaining life of the bearing based on the impedance characteristics of the bearing and the determination map, wherein the probe comprises: a probe main body that comes into contact with a measurement target surface of the bearing to detect the impedance of the bearing; and a substantially cylindrical housing that has a hole therein to accommodate the probe main body. The switch is detachable from the housing.

[0008] According to the determination device of the present invention, the switch can be attached to or detached from the probe depending on the situation, and it is easy to operate.

[0009] FIG. 1 is a schematic diagram of a determination device for determining the degree of fatigue or remaining life of a bearing. FIG. 2 is a schematic diagram of a fatigue determination unit. FIG. 3 is a schematic diagram showing a state in which a probe 10 is used to measure the impedance of a raceway surface 61 of an outer ring 60 of a rolling bearing. FIG. 4 is a perspective view of the probe. FIG. 5 is a cross-sectional view of the probe. FIG. 6 is a cross-sectional view showing a state in which a probe is in perpendicular contact with the raceway surface of the outer ring. FIG. 7 is a view seen in the direction of arrow VII in FIG. 6. FIG. 8 is a cross-sectional view taken along arrows VIII1-VIII1 or VIII2-VIII2 in FIG. 6. FIG. 9 is an enlarged view of the probe in FIG. 7. FIG. 10 is a cross-sectional view showing a state in which a probe is in perpendicular contact with the raceway surface of the inner ring. FIG. 11 is a view seen in the direction of arrow XI in FIG. 10. FIG. 12 is a cross-sectional view taken along arrows XII-XII in FIG. 11. FIG. 13 is a cross-sectional view taken along arrows XIII-XIII in FIG. 11. FIG. 14 is an enlarged view of the probe in FIG. 11. Fig. 15 is an enlarged view of a portion of Fig. 10. Fig. 16 is a view showing a state in which the switch is attached to the probe. Fig. 17 is a view showing a state in which the switch has been moved from the state in Fig. 16 toward the tip of the probe. Fig. 18 is a perspective view of the switch as seen from the front side. Fig. 19 is a perspective view of the switch as seen from the rear side.

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a determination device for determining the fatigue level or remaining life of a bearing according to each embodiment of the present invention will be described in detail with reference to the drawings.

[0011] Fig. 1 is a schematic diagram of a determination device for determining the degree of fatigue or remaining life of a bearing. As shown in Fig. 1, the determination device 1 includes a probe 10 that applies an AC magnetic field to induce eddy currents in the bearing and detects the impedance of the bearing, a switch 30 that transmits a measurement control signal S2 that switches the start and end of acquisition of a measurement signal S1 of the impedance detected by the probe 10, an input unit 40 that acquires the measurement signal S1 and the measurement control signal S2, and a fatigue determination unit 50 that determines the degree of fatigue or remaining life of the bearing based on the impedance of the bearing.

[0012] A coil (not shown) is built into the probe 10. An excitation current is passed through the coil in the probe 10 to apply an AC magnetic field to the bearing to be measured (for example, the outer ring, inner ring, or rolling elements of a rolling bearing), thereby inducing eddy currents, and the impedance generated in the coil by the eddy currents is detected to non-destructively measure the metal structure (for example, the amount of retained austenite). Examples of surfaces to be measured in the bearing include the raceway surface, outer peripheral surface, and both axial end faces of the outer ring, the raceway surface, inner peripheral surface, and both axial end faces of the inner ring, the circumferential surfaces of the rolling elements, and the circumferential surface of the cage.

[0013] When the probe 10 is in contact with the measurement target surface of the bearing, a measurement signal S1 of the bearing impedance is always transmitted to the fatigue determination unit 50 via the input unit 40. However, as will be described later, the fatigue determination unit 50 does not always acquire the measurement signal S1, but switches between acquiring and not acquiring the measurement signal S1 based on the state of a measurement control signal S2 transmitted by the switch 30.

[0014] The switch 30 is a member that can be pressed by a user. For example, when the switch 30 is pressed (ON state), a measurement control signal S2 that switches the start and end of acquisition of the measurement signal S1 is sent to the input unit 40, and when the switch 30 is not pressed (OFF state), the measurement control signal S2 is not sent to the input unit 40. For example, when the measurement control signal S2 is sent to the input unit 40, the measurement signal S1 is acquired by the fatigue determination unit 50, resulting in a measurement execution state in which measurement is performed. When the measurement control signal S2 is not sent to the input unit 40, the measurement signal S1 is not acquired by the fatigue determination unit 50, resulting in a measurement non-execution state in which measurement is not performed.

[0015] The input unit 40 is connected to the probe 10 via a cable 25 (see FIG. 3 ) described below, and includes an A / D converter (not shown) that receives a measurement signal S1 of the bearing impedance detected by the probe 10, and a digital input / output unit (not shown) that is connected to the switch 30 and receives a measurement control signal S2 transmitted by the switch 30. The measurement signal S1 and measurement control signal S2 are transmitted to the fatigue determination unit 50 via the input unit 40.

[0016] 2 is a schematic diagram of the fatigue determination unit. As shown in Fig. 2, the fatigue determination unit 50 includes a map storage unit 51 that stores a determination map including the relationship between the impedance characteristics (resistance component and reactance component) of the bearing and the fatigue level or remaining life of the bearing, a measurement switching unit 53 that switches between a measurement execution state and a measurement non-execution state based on the state of a measurement control signal S2, a data storage unit 55 that stores a measurement signal S1 in the measurement execution state, an impedance characteristics calculation unit 57 that calculates the impedance characteristics (resistance component and reactance component) of the bearing based on the stored measurement signal S1, a determination unit 59 that determines the fatigue level or remaining life of the bearing based on the impedance characteristics (resistance component and reactance component) of the bearing and the determination map, and a display unit 58 that displays the determination result.

[0017] The fatigue determination unit 50 may include, for example, a computer including a processor and peripheral components such as a storage device. The processor may be, for example, a CPU (Central Processing Unit) or an MPU (Micro-Processing Unit). The storage device may include any of a semiconductor storage device, a magnetic storage device, and an optical storage device. The storage device may include memories such as a register, a cache memory, and a ROM (Read Only Memory) and a RAM (Random Access Memory) used as a main storage device. The fatigue determination unit 50 may be configured with dedicated hardware for executing each information processing. For example, the fatigue determination unit 50 may include a functional logic circuit set in a general-purpose semiconductor integrated circuit. For example, the fatigue determining unit 50 may include a programmable logic device (PLD) such as a field-programmable gate array (FPGA).

[0018] The fatigue determination unit 50 determines the remaining life of the bearing by referring to the correlation between the impedance characteristics measured by the probe 10 and the determination map stored in the map memory unit 51, and displays the remaining life on a display unit 58 such as a display.

[0019] FIG. 3 is a schematic diagram showing how the impedance of the raceway surface 61 of the outer ring 60 of a rolling bearing is measured by the probe 10. As shown in FIG. 3, the probe 10 contacts the raceway surface 61 and applies an AC magnetic field to induce eddy currents in the raceway surface 61, thereby detecting the impedance of the raceway surface 61. A measurement signal S1 of the detected impedance is transmitted to the input unit 40 via the cable 25. In this manner, when the measurement target surface is the raceway surface 61 of the outer ring 60, the map storage unit 51 of the fatigue determination unit 50 pre-stores a determination map that includes the relationship between the resistance component and reactance component, which are the impedance characteristics of the raceway surface 61 of the outer ring 60, and the fatigue degree or remaining life of the outer ring 60. Therefore, by measuring the impedance characteristics of the raceway surface 61 of the outer ring 60, the fatigue degree or remaining life of the outer ring 60 can be determined based on the determination map.

[0020] Based on the state of the measurement control signal S2, the measurement switching unit 53 switches between a measurement implementation state in which the measurement signal S1 is taken into the fatigue determination unit 50 and measurement is performed, and a measurement non-implementation state in which the measurement signal S1 is not taken into the fatigue determination unit 50 and measurement is not performed. For example, the measurement switching unit 53 is in the measurement implementation state when the measurement control signal S2 is being sent from the switch 30 to the input unit 40, and is in the measurement non-implementation state when the measurement control signal S2 is not being sent from the switch 30 to the input unit 40. Therefore, the user confirms that the probe 10 is in contact with the raceway surface 61 of the outer ring 60 in the correct posture, and then presses the switch 30 to transition the determination device 1 to the measurement implementation state.

[0021] The data holding unit 55 holds the measurement signal S1 of the impedance of the raceway surface 61 of the outer ring 60 in the measurement implementation state.

[0022] The impedance characteristic calculation unit 57 calculates the resistance component and the reactance component of the impedance of the raceway surface 61 of the outer ring 60 based on the measurement signal S1 stored in the data storage unit 55 .

[0023] The determination unit 59 determines the degree of fatigue or remaining life of the outer ring 60 based on the resistance component and reactance component of the impedance of the raceway surface 61 of the outer ring 60 calculated by the impedance characteristics calculation unit 57 and the determination map stored in the map storage unit 51. The determined degree of fatigue or remaining life of the outer ring 60 is displayed on the display unit 58.

[0024] The fatigue level or remaining life of a bearing is determined by the determination device 1 having the above-described configuration, but in order to accurately measure the impedance of the bearing, it is necessary to stably contact the probe 10 with the measurement target surface in the correct position. The correct position of the probe 10 means, for example, a position in which the probe 10 is perpendicular to the measurement target surface. The configuration of the probe 10 adopted to stably contact the probe 10 with the bearing in the correct position during measurement will be described in detail below.

[0025] Fig. 4 is a perspective view of the probe. Fig. 5 is a cross-sectional view of the probe. As shown in Figs. 4 and 5, the probe 10 includes a substantially cylindrical probe body 11 that abuts against the measurement target surface of the bearing to detect the impedance of the bearing, a housing 13 having a slide hole 14 extending in the axial direction therein and that accommodates the probe body 11 arranged in the slide hole 14 so that it can slide in the axial direction, an abutment portion 15 provided at the tip of the housing 13 and that can abut against the measurement target surface of the bearing, and a coil spring 17 that is arranged in the slide hole 14 of the housing 13 and serves as a biasing spring that axially biases the probe body 11 against the housing 13.

[0026] The housing 13 has an elongated, generally cylindrical shape extending in the axial direction (the longitudinal direction of the housing 13; the vertical direction in FIG. 5 ). It is formed by a generally cylindrical base portion 13a and a generally rectangular parallelepiped tip portion 13b, which are coaxially connected and integrated in the axial direction. The outer peripheral surface 13f of the base portion 13a is cylindrical, and the tip portion 13b has four planar outer peripheral surfaces 13d. The housing 13 is made of resin to minimize any influence on impedance measurement. The sliding hole 14 extends axially through the base portion 13a and the tip portion 13b of the housing 13. Since the sliding hole 14 has the same diameter throughout the entire axial range, the inner diameter of the base portion 13a and the tip portion 13b are the same. Meanwhile, the outer diameter of the tip portion 13b is larger than the outer diameter of the base portion 13a. Therefore, a step portion 13c perpendicular to the axial direction is formed at the connection between the tip portion 13b and the base portion 13a. For example, the user holds the base portion 13a of the housing 13 and abuts the probe 10 against the surface to be measured. Alternatively, the user may hold the tip portion 13b of the housing 13.

[0027] The sliding hole 14 includes a tip opening 14a formed at the tip end (lower part in FIG. 5 ) of the housing 13 and a base opening 14b formed at the base end (upper part in FIG. 5 ) of the housing 13. As will be described later, the probe main body 11 is biased toward the tip end of the probe 10 by a coil spring 17, and this biasing force allows the probe main body 11 to protrude outward from the tip opening 14a of the sliding hole 14. A lid 16 having a through hole 16a at its center is fitted into the base opening 14b of the sliding hole 14. A cable 25 connected to the probe main body 11 is drawn outward from the through hole 16a of the lid 16.

[0028] An elongated hole 13e is formed in one of the four outer peripheral surfaces 13d of the tip portion 13b of the housing 13, penetrating the outer peripheral surface 13d in the radial direction. The elongated hole 13e is an elongated hole whose axial dimension is longer than its dimensions in two directions perpendicular to the axial direction. A pair of pins 24, 24 fixed to a holder portion 22 of the probe main body 11 (described later) is disposed in this elongated hole 13e. When the probe main body 11 slides in the axial direction, the pair of pins 24, 24 slide within the elongated hole 13e. The pair of pins 24, 24 contact both axial ends of the elongated hole 13e (the upper and lower ends in FIG. 5 ) to restrict the sliding, thereby limiting the axial movement distance of the probe main body 11.

[0029] The probe body 11 comprises a probe portion 21 and a holder portion 22, which is separate and stores the probe portion 21 therein and is slidable relative to the sliding hole 14 of the housing 13. By providing the probe portion 21 and the holder portion 22 as separate bodies, if either one is damaged, they can be replaced independently, reducing maintenance costs. The probe portion 21 and the holder portion 22 are made of resin to minimize any influence on impedance measurement.

[0030] The probe section 21 has a generally cylindrical shape and has a coil (not shown) embedded therein. A cable 25 for extracting a measurement signal S1 is connected to the base end side (upper side in FIG. 5 ) of the probe section 21. The cable 25 extends through the sliding hole 14 and is pulled out to the outside from the through-hole 16 a of the lid section 16 installed in the base opening 14 b. The pulled-out cable 25 is connected to the input section 40 (see FIG. 1 ).

[0031] The holder portion 22 has a generally cylindrical shape and covers the outer periphery of the probe portion 21. A pair of female threaded holes 22a, 22a spaced apart from each other in the axial direction is formed in a part of the holder portion 22, and a pin 24 is threadedly engaged with each of the pair of female threaded holes 22a, 22a. The pair of pins 24, 24 fix the probe portion 21 and the holder portion 22. Therefore, when the holder portion 22 slides relative to the slide hole 14, the probe portion 21 also slides integrally. The pair of pins 24, 24 protrude radially outward beyond the pair of female threaded holes 22a, 22a, and contact both axial ends of the elongated hole 13e to restrict sliding, thereby limiting the axial movement distance of the probe main body 11.

[0032] The probe main body 11, which is made up of the probe portion 21 and the holder portion 22, is disposed on the distal end side of the sliding hole 14. Meanwhile, a coil spring 17 is disposed on the proximal end side of the sliding hole 14. The coil spring 17 extends in the axial direction so as to abut against the lid portion 16 fixed to the housing 13 and the probe main body 11. As a result, the probe main body 11 is biased by the coil spring 17 toward the distal end side relative to the housing 13.

[0033] In this embodiment, the coil spring 17 abuts against the holder portion 22 located on the outer periphery of the probe body 11. Therefore, the outer diameter of the coil spring 17 can be set to be approximately equal to the inner diameter of the sliding hole 14, and the coil spring 17 can be configured to be guided by the sliding hole 14, which prevents the coil spring 17 from buckling and stabilizes the biasing force.

[0034] Furthermore, a gap exists on the inner diameter side of the coil spring 17, and the cable 25 of the probe main body 11 extends through this gap. In this way, the cable 25 is disposed in the dead space on the inner diameter side of the coil spring 17, which contributes to miniaturization of the probe 10.

[0035] Fig. 6 is a cross-sectional view showing a state in which a probe is in contact perpendicularly with the raceway surface of the outer ring. Fig. 7 is a view seen in the direction of arrow VII in Fig. 6. Fig. 8 is a cross-sectional view taken along arrows VIII1-VIII1 or VIII2-VIII2 in Fig. 6. Fig. 9 is an enlarged view of the probe in Fig. 7.

[0036] As shown in Figures 4 to 9, the substantially rectangular parallelepiped tip 13b of the housing 13 is provided with an abutment 15 that can abut against the raceway surface 61 of the outer ring 60, which is the surface to be measured. The raceway surface 61 of the outer ring 60 used in the description of the embodiment is a concave spherical surface. The raceway surface 61 may have any shape, and may be cylindrical, for example. As shown in Figures 7 and 9 in particular, the shape of the abutment 15 as viewed from the axial direction is preferably rectangular, and in the illustrated example, it is square.

[0037] The abutting portion 15 has four protrusions 26 of the same shape that protrude in the axial direction. As shown in FIG. 9 , the protrusions 26 are substantially rectangular, and the tip surfaces 26 a of the protrusions 26 are rectangular. The four protrusions 26 are arranged at the vertices of the rectangle of the abutting portion 15. Furthermore, when viewed from the axial direction, the four protrusions 26 are each located at the vertices of a rectangle R whose center is the central axis O1 of the probe main body 11. In FIG. 9 , the rectangle R is a square indicated by a dashed line, and is formed by connecting the centers of the tip surfaces 26 a of the four protrusions 26. Therefore, the four protrusions 26 are arranged at positions equidistant from the central axis O1 and at equal intervals in the circumferential direction around the central axis O1. Note that the rectangle R does not necessarily have to be square and may be, for example, rectangular. Furthermore, it is preferable that the rectangle R has a similar shape to the rectangle of the abutting portion 15.

[0038] 6 to 9, during measurement, it is necessary to maintain the correct posture of the probe 10 so that it is perpendicular to the raceway surface 61 of the outer ring 60. Therefore, the user makes sure that all four protrusions 26 of the abutment portion 15 are in contact with the raceway surface 61 of the outer ring 60.

[0039] The four protrusions 26 contact the raceway surface 61, which is a concave spherical surface, at the outer corners 26b that are farthest from the central axis O1 of the probe main body 11. By bringing the outer corners 26b of each of the four protrusions 26 into contact with the raceway surface 61 in this way, the probe main body 11 can be maintained perpendicular to the raceway surface 61, and stable measurement results can be obtained.

[0040] When the outer corners 26b of all four protrusions 26 come into contact with the raceway surface 61, the user can perceive that the wobble of the probe 10 being held has been resolved and the posture of the probe 10 has stabilized. The user then presses the switch 30 to start capturing the measurement signal S1, and the fatigue level or remaining life of the bearing is determined.

[0041] If the raceway surface 61 has a cylindrical shape concentric with the central axis O2 of the outer ring 60, it is necessary to maintain the probe 10 in a correct orientation perpendicular to the raceway surface 61 during measurement. In this case, as shown in FIG. 9 , adjustments are made so that the central axis O1 of the probe body 11 and the central axis O2 of the outer ring 60 are perpendicular, two parallel sides r1 and r2 of the four sides constituting the rectangle R are parallel to the central axis O2 of the outer ring 60, and the other two parallel sides r3 and r4 of the four sides constituting the rectangle R are perpendicular to the central axis O2 of the outer ring 60. A pair of protrusions 26, 26 on one circumferential side (upper side in FIG. 9 ) are spaced apart in the direction of the central axis O2 of the outer ring 60, and similarly, a pair of protrusions 26, 26 on the other circumferential side (lower side in FIG. 9 ) are also spaced apart in the direction of the central axis O2 of the outer ring 60. Note that the locations at which the four protrusions 26 contact the raceway surface 61 differ from those in the case where the raceway surface 61 is a concave spherical surface. When the raceway surface 61 has a cylindrical shape, the four protrusions 26 contact the raceway surface 61 at the circumferential outer sides 26d including the outer corners 26b.

[0042] Next, a case where a raceway surface 71 formed on the outer peripheral surface of the inner ring 70 is measured will be described. Fig. 10 is a cross-sectional view showing a state where a probe is brought into contact perpendicularly with the raceway surface of the inner ring. Fig. 11 is a view seen in the direction of arrow XI in Fig. 10. Fig. 12 is a cross-sectional view taken along arrows XII-XII in Fig. 11. Fig. 13 is a cross-sectional view taken along arrows XIII-XIII in Fig. 11. Fig. 14 is an enlarged view of the probe in Fig. 11. Fig. 15 is a partial enlarged view of Fig. 10.

[0043] In the illustrated example, double-row raceway surfaces 71, 71 are formed on the outer peripheral surface of the inner ring 70. The raceway surfaces 71 are convexly curved. The raceway surfaces 71 may have any shape, for example, a cylindrical shape. As shown in FIGS. 10 to 15 , during measurement, the probe 10 must be maintained in a correct orientation perpendicular to the raceway surface 71 of the inner ring 70. Therefore, the user adjusts the orientation of the probe 10 so that all four protrusions 26 of the abutment portion 15 are in contact with the raceway surface 71 of the inner ring 70. Specifically, as shown in FIGS. 14 and 15 , the central axis O1 of the probe body 11 and the normal direction O4 of the contact angle α of the inner ring 70 are perpendicular, two parallel sides r1 and r2 of the four sides constituting the rectangle R are parallel to the normal direction O4 of the contact angle α, and the other two parallel sides r3 and r4 of the four sides constituting the rectangle R are perpendicular to the normal direction O4 of the contact angle α.

[0044] Here, the normal direction O4 of the contact angle α will be described with reference to FIG. 15 . In FIG. 15 , α is the contact angle, O3 is the central axis of the inner ring 70, O4 is the normal direction of the contact angle α, and O5 is the contact angle direction. The contact angle α is defined as the "nominal contact angle" described in Japanese Industrial Standard JIS B 0104-1991, "Rolling Bearing Terminology," and is the angle formed by a plane S perpendicular to the central axis O3 of the inner ring 70 and the contact angle direction O5. The contact angle direction O5 is the direction of the line of action of the load, which is the direction of the force applied to the inner ring 70 from the rolling elements (not shown). The normal direction O4 of the contact angle α is a direction passing through the raceway surface 71 and perpendicular to the contact angle direction O5. When the probe 10 is correctly oriented perpendicular to the raceway surface 71, the central axis O1 of the probe body 11 coincides with the contact angle direction O5 and is perpendicular to the normal direction O4 of the contact angle α.

[0045] When the four protrusions 26 are brought into contact with the raceway surface 71 in this way, a pair of the protrusions 26 is located on each side in the circumferential direction, sandwiching the normal direction O4 of the contact angle α, as shown in Fig. 14. The pair of protrusions 26, 26 on one circumferential side (upper side in Fig. 14) are spaced apart in the normal direction O4 of the contact angle α, and similarly, the pair of protrusions 26, 26 on the other circumferential side (lower side in Fig. 14) are also spaced apart in the normal direction O4 of the contact angle α of the inner ring 70.

[0046] The four protrusions 26 contact the raceway surface 71, which is a convex curved surface, at their inner corners 26c. Of the four corners of the tip surface 26a of the protrusions 26, the inner corners 26c are those that are located on the outer side with respect to the normal direction O4 of the contact angle α and on the inner side in the circumferential direction. By bringing the inner corners 26c of each of the four protrusions 26 into contact with the raceway surface 71 in this way, the probe main body 11 can be maintained perpendicular to the raceway surface 71, and stable measurement results can be obtained.

[0047] When the inner corners 26c of all four protrusions 26 come into contact with the raceway surface 71, the user can perceive that the wobble of the probe 10 being held has been eliminated and the posture of the probe 10 has stabilized. The user then presses the switch 30 to start capturing the measurement signal S1, and the fatigue level or remaining life of the bearing is determined.

[0048] Even when the raceway surface 71 has a cylindrical shape concentric with the central axis O3 of the inner ring 70, it is necessary to maintain the probe 10 in a correct orientation perpendicular to the raceway surface 71 during measurement. In this case, although not specifically shown, adjustments can be made so that the central axis O1 of the probe body 11 and the central axis O3 of the inner ring 70 are perpendicular, two parallel sides r1 and r2 of the four sides that make up the rectangle R are parallel to the central axis O3 of the inner ring 70, and the other two parallel sides r3 and r4 of the four sides that make up the rectangle R are perpendicular to the central axis O3 of the inner ring 70. A pair of protrusions 26, 26 on one circumferential side (upper side in FIG. 14 ) are spaced apart from each other in the direction of the central axis O3 of the inner ring 70, and similarly, a pair of protrusions 26, 26 on the other circumferential side (lower side in FIG. 14 ) are also spaced apart from each other in the direction of the central axis O3 of the inner ring 70. The locations at which the four protrusions 26 contact the raceway surface 71 differ from those in the case where the raceway surface 71 is a convex spherical surface. When the raceway surface 71 has a cylindrical shape, the four protrusions 26 contact the raceway surface 61 at the circumferential inner sides 26e (see FIG. 14) including the inner corners 26c.

[0049] In the illustrated example, the shape of the abutting portion 15 when viewed from the axial direction is rectangular, and the four protrusions 26 are arranged at the vertices of the rectangle of the abutting portion 15. Therefore, the four protrusions 26 can be provided on the abutting portion 15 with efficient use of space, and the distance between adjacent protrusions 26 can be increased, thereby stabilizing the posture of the probe 10.

[0050] The shape of the abutment portion 15 as viewed from the axial direction is not limited to a rectangle, but may be any shape, for example, a circle for ease of manufacture.

[0051] In the illustrated example, the tip surfaces 26a of the protrusions 26 are rectangular when viewed in the axial direction. This allows the orientation of the probe 10 to be stably maintained when the measurement target surface is the raceway surface 61 of the outer ring 60, which is a concave spherical surface, by bringing the outer corners 26b of each of the four protrusions 26 into contact with the raceway surface 61. If the measurement target surface is the raceway surface 71 of the inner ring 70, which is a convex curved surface, the orientation of the probe 10 can be stably maintained by bringing the inner corners 26c of each of the four protrusions 26 into contact with the measurement target surface. Furthermore, although not specifically illustrated, when the measurement target surface is a flat surface, the orientation of the probe 10 can be stably maintained by bringing the entire tip surfaces 26a of the four protrusions 26 into contact with the measurement target surface.

[0052] The shape of the tip surface 26a of the projection 26 as viewed in the axial direction is not limited to a rectangle, but may be any shape, for example, a circle for ease of manufacture.

[0053] In the illustrated example, the protrusion 26 is provided integrally with the abutment portion 15, but the protrusion 26 may also be a pin separate from the abutment portion 15. In this case, the pin constituting the protrusion 26 may be fixed by any method, for example, by gluing it to the abutment portion 15 or by press-fitting or screwing it into a hole formed in the abutment portion 15. By providing the protrusion 26 as a separate part in this way, the protrusion 26 can be replaced if it is damaged or worn. Furthermore, the protrusion 26 can be replaced with an appropriate protrusion 26 for different measurement target surfaces depending on their characteristics such as shape and roughness.

[0054] As described above, the user confirms that the probe 10 is in contact with the raceway surface 61 of the outer ring 60 and the raceway surface 71 of the inner ring 70 in the correct orientation, and then presses the switch 30 to transition the determination device 1 to a measurement execution state. The present inventors have conceived the idea that operability can be improved by attaching and detaching the switch 30 to and from the probe 10 depending on the usage situation of the probe 10. For example, when inserting the probe 10 into a narrow space such as a gap in a bearing to perform a measurement, detaching the switch 30 from the probe 10 improves operability. Furthermore, for example, when holding and operating the probe 10 with the right hand while supporting the bearing with the left hand, attaching the switch 30 to the probe 10 is preferable because it allows the switch 30 to be pressed with the right hand. The configuration for enabling the switch 30 to be attached and detached to and from the probe 10 will be described in detail below.

[0055] Fig. 16 is a diagram showing a state in which the switch is attached to the probe. Fig. 17 is a diagram showing a state in which the switch has been moved from the state in Fig. 16 toward the tip of the probe. Fig. 18 is a perspective view of the switch as seen from the front side. Fig. 19 is a perspective view of the switch as seen from the rear side.

[0056] 16 to 19, the switch 30 has a substantially annular ring portion 31 and a main body portion 32 on which a first button 33a, a second button 33b, a third button 33c, and a second button 33b that can be pressed by a user are formed. In the illustrated example of the switch 30, the ring portion 31 and the main body portion 32 are separate members that are detachable from each other, but the ring portion 31 and the main body portion 32 may also be formed as an integral member.

[0057] The ring portion 31 has a substantially annular shape centered on the central axis P. The ring portion 31 is preferably made of an elastically deformable material, such as resin, rubber, string, tape, etc. If the ring portion 31 is elastically deformable, it is easy to attach the ring portion 31 to the probe 10, the user's finger, etc.

[0058] The ring portion 31 includes a base portion 31a to which the main body portion 32 is fixed, and a pair of clamping pieces 31b, 31b connected to both ends of the base portion 31a and extending around the central axis P in a generally C-shaped cross section.

[0059] An engaged portion made of unevenness (not shown) or the like is provided on the surface of the base portion 31a facing the main body portion 32. An engaging portion made of unevenness (not shown) or the like of the main body portion 32 engages with the engaged portion of the base portion 31a, thereby engaging and integrating the ring portion 31 and the main body portion 32. Note that the engagement between the engaged portion of the ring portion 31 and the engaging portion of the main body portion 32 is not limited to the engagement of uneven shapes as described above, and may be, for example, engagement by a hook-and-loop fastener or engagement by a magnet.

[0060] A recess 31c is formed at the base end of each clamping piece 31b, facing inward, and this recess 31c promotes elastic deformation of the clamping piece 31b. The tip ends of the pair of clamping pieces 31b, 31b face each other with a gap T therebetween. By providing this gap T, the ring portion 31 of the switch 30 has a shape in which a portion of its circumference is cut out.

[0061] The probe 10 or the user's finger is inserted into the internal space of the ring portion 31 between the pair of clamping pieces 31b, 31b, and the pair of clamping pieces 31b, 31b elastically clamp the probe 10 or the user's finger. Since the probe 10 or the like can be inserted into the internal space of the ring portion 31 through the gap T, the insertion operation is very easy.

[0062] In particular, since the probe 10 has the cable 25, if the gap T were not formed, it would be difficult to attach the ring portion 31 to the probe 10 from the proximal end side (the upper side in FIGS. 16 and 17 ). However, according to the ring portion 31 of this embodiment, the cable 25 can be passed through the cutout portion (gap T) of the ring portion 31, making it easy to fix the ring portion 31 to the probe 10.

[0063] The ring portion 31 of the switch 30 is preferably 13 mm to 30 mm in diameter. By setting the size in this range, the user can operate the switch 30 by putting the ring portion 31 on their finger.

[0064] The main body 32 is a substantially disc-shaped member and houses a battery therein that supplies power to the main body 32. First to third buttons 33a to 33c are formed on the front side of the main body 32, opposite the ring portion 31. A second button 33b is provided in the center of the front side of the main body 32, and a first button 33a and a third button 33c are provided on both sides of the second button 33b in the direction of the central axis P.

[0065] The pushing direction of the central second button 33b is a radial direction Q (see FIG. 16 ) relative to the central axis P of the ring portion 31. That is, the pushing direction of the second button 33b has only a radial component parallel to the radial direction Q, and does not have an axial component parallel to the central axis P. Therefore, the surface of the second button 33b is perpendicular to the radial direction Q.

[0066] In contrast, the surfaces of the first button 33a and the third button 33c on both sides of the second button 33b are inclined in a direction approaching the central axis P with respect to the pressing surface of the second button 33b. As a result, the pressing direction of the first button 33a and the third button 33c has both an axial component parallel to the central axis P of the ring portion 31 and a radial component parallel to the radial direction Q. In other words, when the first button 33a and the third button 33c are pressed, they are pressed not only in the radial direction Q but also in the direction of the central axis P. By setting the pressing directions of the first button 33a and the third button 33c in this manner, when the switch 30 is attached to the probe 10 as shown in FIGS. 16 and 17 , the user can easily press the first button 33a and the third button 33c while holding the probe 10.

[0067] When at least one of the first to third buttons 33a to 33c is pressed, the main body 32 transmits to the input unit 40 (see FIG. 1) a measurement control signal S2 that switches the start and end of acquisition of a measurement signal S1 of the impedance detected by the probe 10. At this time, the switch 30 transmits the measurement control signal S2 wirelessly. This makes it possible to avoid interference between the measurement signal S1 of the probe 10 transmitted by cable 25 and the measurement control signal S2 of the switch 30. Furthermore, because the switch 30 does not have any wiring, it is easy to attach it to the probe 10.

[0068] The switch 30 configured as described above is detachable from the outer peripheral surfaces 13f, 13d of the housing 13 of the probe 10. Although Figures 16 and 17 show the switch 30 attached to the outer peripheral surface 13f of the cylindrical base portion 13a of the housing 13, the switch 30 may also be attached to the outer peripheral surface 13d of the rectangular parallelepiped tip portion 13b.

[0069] However, because a user typically grips base portion 13a rather than tip portion 13b, it is preferable to attach switch 30 to outer peripheral surface 13f of base portion 13a to make it easier to operate switch 30 while gripping it. Also, because outer peripheral surface 13f of base portion 13a is a cylindrical surface, it is possible to easily attach substantially annular ring portion 31 of switch 30. On the other hand, if the cross-sectional shape is rectangular rather than circular, as with outer peripheral surface 13d of tip portion 13b, the switch must be oriented appropriately to attach, making the installation process cumbersome.

[0070] A step 13c is formed between an outer peripheral surface 13f of the base 13a of the housing 13 and an outer peripheral surface 13d of the tip 13b, and Fig. 17 shows the ring 31 abutting against this step 13c. By restricting the axial movement of the switch 30 by the step 13c in this way, the switch 30 is less likely to slip out of position when the user operates the switch 30 (particularly when the user presses the first button 33a, which is pressed toward the tip of the probe 10), improving usability.

[0071] Although not specifically shown, the step portion is not limited to the step portion 13c as shown in the figure, and any shape and arrangement may be used as long as it can regulate the axial movement of the switch 30. For example, the step portion may be formed by a recess or protrusion provided on the outer peripheral surface 13f of the base portion 13a, or may be formed by a recess or protrusion provided on the outer peripheral surface 13f of the tip portion 13b.

[0072] In the illustrated example, the ring portion 31 of the switch 30 is detachable from the probe 10, but the main body portion 32 of the switch 30 may be detachable from the probe 10. That is, the ring portion 31 and the main body portion 32 of the switch 30 may be separate members, and a configuration may be adopted in which the main body portion 32 can be detached from the ring portion 31 and only the main body portion 32 can be attached to the housing 13 of the probe 10.

[0073] As described above, an engaged portion made of unevenness or the like (not shown) is provided on the surface of the base portion 31a facing the main body portion 32. An engaging portion made of unevenness or the like (not shown) of the main body portion 32 engages with the engaged portion of the base portion 31a, thereby engaging and integrating the ring portion 31 and the main body portion 32. Therefore, although not particularly shown, if an engaged portion made of unevenness or the like similar to the engaged portion of the base portion 31a is provided on the outer peripheral surfaces 13d, 13f of the housing 13 of the probe 10, the engaging portion of the main body portion 32 of the switch 30 can engage with the engaged portion of the housing 13. Note that the engagement between the engaged portion of the housing 13 of the probe 10 and the engaging portion of the main body portion 32 is not limited to the engagement of uneven shapes as described above, and may be, for example, engagement by a hook-and-loop fastener or a magnet.

[0074] In this way, if the main body 32 of the switch 30 is detachable from the ring portion 31 of the switch 30 and the outer circumferential surfaces 13d, 13f of the housing 13, the main body 32 having the first to third buttons 33a to 33c can be easily handled. For example, the main body 32 can be removed from the ring portion 31 on the user's finger while the ring portion 31 remains on the user's finger, and then attached to the housing 13 of the probe 10. Furthermore, the main body 32 can be removed from the housing 13 and attached to the ring portion 31 while it remains on the user's finger.

[0075] The present invention is not limited to the above-described embodiments, and modifications and improvements are possible as appropriate.

[0076] As described above, the present specification discloses the following: (1) A determination device comprising: a probe that applies an AC magnetic field to induce eddy currents in a bearing and detects the impedance of the bearing; a switch that transmits a measurement control signal that switches between starting and stopping the acquisition of a measurement signal of the impedance detected by the probe; and a fatigue determination unit that determines the fatigue level or remaining life of the bearing based on the impedance of the bearing, wherein the fatigue determination unit comprises: a map storage unit that stores a determination map including the relationship between the impedance characteristics of the bearing and the fatigue level or remaining life of the bearing; a measurement switching unit that switches between a measurement execution state and a measurement non-execution state based on the state of the measurement control signal; a data storage unit that stores the measurement signals in the measurement execution state; an impedance characteristic calculation unit that calculates the impedance characteristics of the bearing based on the stored measurement signals; and a determination unit that determines the fatigue level or remaining life of the bearing based on the impedance characteristics of the bearing and the determination map, wherein the probe comprises: a probe main body that comes into contact with a measurement target surface of the bearing to detect the impedance of the bearing; and a substantially cylindrical housing that has a hole therein to accommodate the probe main body. The determination device, wherein the switch is detachable from the housing. (2) The determination device according to (1), wherein the switch is detachable from the outer circumferential surface of the housing, and the outer circumferential surface of the housing is a cylindrical surface. (3) The determination device according to (1) or (2), wherein a step portion is formed on the outer circumferential surface of the housing. (4) The determination device according to any one of (1) to (3), wherein the switch transmits the measurement control signal wirelessly. (5) The determination device according to any one of (1) to (4), wherein the switch includes: a substantially annular ring portion detachable from the outer circumferential surface of the housing; and a main body portion on which a button that can be pressed by a user is formed. (6) The determination device according to (5), wherein the ring portion of the switch has an inner diameter of 13 mm to 30 mm. (7) The determination device according to (5) or (6), wherein the ring portion of the switch is made of an elastically deformable material.(8) The determination device according to any one of (5) to (7), wherein the ring portion of the switch has a portion cut out in the circumferential direction. (9) The determination device according to any one of (5) to (8), wherein a pressing direction of the button of the main body portion of the switch has an axial component parallel to a central axis of the ring portion and a radial component parallel to a radial direction relative to the central axis of the ring portion. (10) The determination device according to any one of (5) to (9), wherein the ring portion and the main body portion of the switch are separate members, and the main body portion is detachable from both the ring portion and the outer circumferential surface of the housing.

[0077] This application is based on a Japanese patent application (Patent Application No. 2024-036004) filed on March 8, 2024, the contents of which are incorporated herein by reference.

[0078] REFERENCE SIGNS LIST 1 Determination device 10 Probe 11 Probe body 13 Housing 13a Base 13b Tip 13c Step 13d Outer peripheral surface of tip 13e Long hole 13f Outer peripheral surface of base 13f Outer peripheral surface of base 14 Slide hole (hole) 14a Tip opening 14b Base opening 15 Abutment 17 Coil spring (biasing spring) 21 Probe part 22 Holder part 22a Female thread hole 24 Pin 25 Cable 26 Protrusion 26a Tip surface 26b Outer corner 26c Inner corner 26d Circumferential outer side 26e Circumferential inner side 30 Switch 31 Ring part 31a Base part 31b Clamping piece 31c Recess 32 Main body part 33a First button 33b Second button 33c Third button 40 Input section 50 Fatigue determination section 51 Map storage section 53 Measurement switching section 55 Data storage section 57 Impedance characteristics calculation section 58 Display section 59 Determination section 60 Outer ring (bearing) 61 Raceway surface (surface to be measured) 70 Inner ring (bearing) 71 Raceway surface (surface to be measured) O1 Central axis of probe body O2 Central axis of outer ring O3 Central axis of inner ring O4 Normal direction of contact angle O5 Contact angle direction P Central axis of ring part of switch Q Radial direction of ring part of switch T Clearance

Claims

1. A determination device comprising: a probe that applies an AC magnetic field to induce eddy currents in a bearing and detects the impedance of the bearing; a switch that transmits a measurement control signal that switches between starting and stopping the acquisition of a measurement signal of the impedance detected by the probe; and a fatigue determination unit that determines the fatigue level or remaining life of the bearing based on the impedance of the bearing, wherein the fatigue determination unit comprises: a map storage unit that stores a determination map including the relationship between the impedance characteristics of the bearing and the fatigue level or remaining life of the bearing; a measurement switching unit that switches between a measurement execution state and a measurement non-execution state based on the state of the measurement control signal; a data retention unit that retains the measurement signals in the measurement execution state; an impedance characteristics calculation unit that calculates the impedance characteristics of the bearing based on the retained measurement signals; and a determination unit that determines the fatigue level or remaining life of the bearing based on the impedance characteristics of the bearing and the determination map, wherein the probe comprises: a probe main body that comes into contact with the measurement target surface of the bearing to detect the impedance of the bearing, and a substantially cylindrical housing that has a hole inside it to accommodate the probe main body, The switch is detachable from the housing.

2. The determination device according to claim 1, wherein the switch is detachable from the outer peripheral surface of the housing, and the outer peripheral surface of the housing is a cylindrical surface.

3. The determination device according to claim 1, wherein a step is formed on the outer peripheral surface of the housing.

4. The determination device according to claim 1, wherein the switch transmits the measurement control signal wirelessly.

5. The determination device according to claim 1, wherein the switch includes: a substantially annular ring portion that is detachable from the outer peripheral surface of the housing; and a main body portion on which a button that can be pressed by a user is formed.

6. The determination device according to claim 5, wherein the ring portion of the switch has an inner diameter of 13 mm to 30 mm.

7. The determination device according to claim 5, wherein the ring portion of the switch is made of an elastically deformable material.

8. The determination device according to claim 5, wherein a portion of the ring portion of the switch is cut out in the circumferential direction.

9. The determination device according to claim 5, wherein the direction in which the button on the main body of the switch is pressed has an axial component parallel to the central axis of the ring portion and a radial component parallel to the radial direction relative to the central axis of the ring portion.

10. The determination device according to claim 5, wherein the ring portion and the main body portion of the switch are separate members, and the main body portion is detachable from both the ring portion and the outer peripheral surface of the housing.

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