Determination device

Abstract

According to the present invention, a probe comprises: a substantially columnar probe body that is in contact with a measurement target surface of a bearing and detects the impedance of the bearing; a housing which has therein a sliding hole extending in the axial direction, and in which the probe body disposed in the sliding hole is accommodated so as to be able to slide in the axial direction; an abutting part that is provided at a tip part of the housing and can abut against the measurement target surface of the bearing; and a biasing spring that is disposed in the sliding hole of the housing and biases the probe body in the axial direction with respect to the housing. The abutting part has four protrusions that protrude in the axial direction, and when viewed in the axial direction, the four protrusions are respectively positioned at the vertices of a rectangle centered on the central axis of the probe body.

Description

Technical Field

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

Background Art

[0002] For example, rolling bearings for papermaking machinery, wind power generation equipment, mining and construction equipment, and railway vehicles are used under severe lubrication conditions with heavy loads and intrusion of foreign matter and water, so peeling on the bearing raceway surface is a problem. When peeling occurs in a rolling bearing, it may not only cause significant damage to products and equipment, but also affect manufacturing delivery dates and schedules. In order to prevent sudden peeling, rolling bearings are regularly disassembled and cleaned, and visual inspection of the raceway surface is sometimes performed. However, the prediction of the remaining life of a bearing (estimation of the period until peeling occurs) based on visual inspection depends on the experience and skills of the operator, and quantitative prediction has been difficult.

[0003] In contrast, Patent Document 1 discloses a prediction method that non-destructively inspects a rolling bearing used by a user and predicts the degree of fatigue progress or remaining life of the rolling bearing. Specifically, the prediction method of Patent Document 1 comprises the steps of: previously creating a map in which the fatigue progress degree or remaining life at each coordinate is associated with a map representing, on X-Y coordinate axes, output voltage values obtained by performing eddy current measurement on a rolling bearing; measuring output voltage values of the raceway surface or rolling surface of the rolling bearing with an eddy current measuring device; and obtaining the degree of fatigue progress or remaining life of the rolling bearing by superimposing the measured output voltage values of the rolling bearing on the map. Thereby, it is intended that the bearing used by a user is non-destructively inspected, and the degree of fatigue progress or remaining life of the rolling bearing can be predicted with high accuracy before damage due to fatigue progress occurs in the bearing.

Prior Art Literature

Patent Literature

[0004]

Patent Document 1

Summary of the Invention

[0005] The eddy current measuring device described in Patent Document 1 nondestructively measures the amount of retained austenite by inducing eddy currents in the target metal (outer ring, inner ring, and rolling elements of a rolling bearing) by passing an excitation current through a coil in the probe, and detecting the output voltage value generated in the coil by the eddy currents. Therefore, for example, when measuring the output voltage value of the outer ring raceway surface with the eddy current measuring device, it is necessary to make stable and correct contact of the probe with the outer ring raceway surface. If the position of the probe relative to the outer ring shifts during measurement, the measured value will also change, making it impossible to accurately predict the fatigue progression or remaining life of the rolling bearing. In particular, when the surface to be measured is curved, it is difficult to maintain the position while making proper contact of the probe with the curved surface.

[0006] The present invention has been made in view of the above-mentioned problems, and its objective is to provide a determination device that can stabilize the position of the probe relative to the bearing and accurately determine the fatigue level or remaining life of the bearing. [Means for solving the problem]

[0007] Therefore, the above objective of the present invention is achieved by the configuration described in [1] below. [1] A probe that induces eddy currents in a bearing by applying an alternating magnetic field and detects the impedance of the bearing, A switch that transmits a measurement control signal to switch the start and end of acquiring the impedance measurement signal detected by the probe, Based on the impedance of the bearing, a fatigue determination unit for determining the fatigue degree or remaining life of the bearing is provided. A determination device comprising, The fatigue determination unit is, A map storage unit that stores a determination map including the relationship between the impedance characteristics of the bearing and the fatigue degree 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, In the measurement execution state, a data holding unit holds the measurement signal, An impedance characteristic calculation unit calculates the impedance characteristics of the bearing based on the held measurement signal, 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, Equipped with, The aforementioned probe A substantially columnar probe body that contacts the surface of the bearing to be measured and detects the impedance of the bearing, A housing having a sliding hole extending in the axial direction inside, the housing slidably housing the probe body positioned in the sliding hole in the axial direction, An abutment portion provided at the tip of the housing and capable of abutting against the surface of the bearing to be measured, A biasing spring is positioned in the sliding hole of the housing and biases the probe body axially relative to the housing, Equipped with, The aforementioned abutment portion has four projections that protrude in the axial direction, Viewed from the axial direction, each of the four protrusions is located at the vertex of a rectangle centered on the central axis of the probe body. Judgment device. [Effects of the Invention]

[0008] According to the determination device of the present invention, the position of the probe relative to the bearing can be stabilized, and the fatigue level or remaining life of the bearing can be accurately determined. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a schematic diagram of a device for determining the fatigue level or remaining life of a bearing. [Figure 2] Figure 2 is a schematic diagram of the fatigue determination unit. [Figure 3]FIG. 3 is a schematic diagram showing a state where the impedance of the raceway surface of an outer ring of a rolling bearing is measured by a probe. [Figure 4] FIG. 4 is a perspective view of the probe. [Figure 5] FIG. 5 is a cross-sectional view of the probe. [Figure 6] FIG. 6 is a cross-sectional view showing a state where the probe is brought into perpendicular contact with the raceway surface of the outer ring. [Figure 7] FIG. 7 is a view seen along the direction of arrow VII in FIG. 6. [Figure 8] FIG. 8 is a cross-sectional view taken along line VIII1-VIII1 or a cross-sectional view taken along line VIII2-VIII2 in FIG. 6. [Figure 9] FIG. 9 is an enlarged view of the probe in FIG. 7. [Figure 10] FIG. 10 is a cross-sectional view showing a state where the probe is brought into perpendicular contact with the raceway surface of an inner ring. [Figure 11] FIG. 11 is a view seen along the direction of arrow XI in FIG. 10. [Figure 12] FIG. 12 is a cross-sectional view taken along line XII-XII in FIG. 11. [Figure 13] FIG. 13 is a cross-sectional view taken along line XIII-XIII in FIG. 11. [Figure 14] FIG. 14 is an enlarged view of the probe in FIG. 11. [Figure 15] FIG. 15 is a partially enlarged view of FIG. 11. MODE FOR CARRYING OUT THE INVENTION

[0010] Hereinafter, a determination device for determining the fatigue degree 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] Figure 1 is a schematic diagram of a determination device for determining the fatigue level or remaining life of a bearing. As shown in Figure 1, the determination device 1 comprises a probe 10 that induces eddy currents in the bearing by applying an alternating magnetic field and detects the impedance of the bearing; a switch 30 that transmits a measurement control signal S2 to switch the start and end of acquiring the impedance measurement signal S1 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 fatigue level or remaining life of the bearing based on the impedance of the bearing.

[0012] The probe 10 has a coil (not shown) built inside. By passing an excitation current through the coil in the probe 10 and applying an alternating magnetic field to the bearing to be measured (for example, the outer ring, inner ring, or rolling elements of a rolling bearing), eddy currents are induced. By detecting the impedance generated in the coil by these eddy currents, the metal structure (for example, the amount of retained austenite) can be measured non-destructively. Examples of surfaces to be measured in a bearing include the raceway surface, outer surface, and axial end faces of the outer ring, the raceway surface, inner surface, and axial end faces of the inner ring, and the circumferential surfaces of the rolling elements.

[0013] When the probe 10 is in contact with the surface of the bearing to be measured, the bearing impedance measurement signal S1 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, and the acquisition of the measurement signal S1 is switched on or off based on the state of the measurement control signal S2 transmitted by the switch 30.

[0014] Switch 30 is a component that can be pressed by the user. For example, when switch 30 is pressed (ON state), a measurement control signal S2 that switches the start and end of acquiring the measurement signal S1 is sent to the input unit 40, and when 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 and measurement is performed, resulting in a measurement execution state, and 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 and measurement is not performed, resulting in a measurement non-execution state.

[0015] The input unit 40 is connected to the probe 10 via a cable 25 (see Figure 3) described later 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 a switch 30 and receives a measurement control signal S2 transmitted by the switch 30. The measurement signal S1 and the measurement control signal S2 are transmitted to the fatigue determination unit 50 via the input unit 40.

[0016] Figure 2 is a schematic diagram of the fatigue determination unit. As shown in Figure 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 the measurement control signal S2; a data storage unit 55 that holds the measurement signal S1 in the measurement execution state; an impedance characteristic calculation unit 57 that calculates the impedance characteristics (resistance component and reactance component) of the bearing based on the held 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 memory device. The processor may be, for example, a CPU (Central Processing Unit) or an MPU (Micro-Processing Unit). The memory device may include any of semiconductor memory devices, magnetic memory devices, and optical memory devices. The memory device may include registers, cache memory, and memory such as ROM (Read Only Memory) and RAM (Random Access Memory) used as main memory. The fatigue determination unit 50 may be composed of dedicated hardware for executing each information processing. For example, the fatigue determination unit 50 may include functional logic circuits set in a general-purpose semiconductor integrated circuit. For example, the fatigue determination unit 50 may have 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 storage unit 51, and displays it on a display unit 58 such as a display.

[0019] Figure 3 is a schematic diagram showing the measurement of the impedance of the raceway surface 61 of the outer ring 60 of a rolling bearing by the probe 10. As shown in Figure 3, the probe 10 contacts the raceway surface 61 and applies an alternating magnetic field to induce eddy currents in the raceway surface 61, thereby detecting the impedance of the raceway surface 61. The detected impedance measurement signal S1 is transmitted to the input unit 40 via the cable 25. When the surface to be measured is the raceway surface 61 of the outer ring 60, the map storage unit 51 of the fatigue determination unit 50 has previously stored 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] The measurement switching unit 53 switches between a measurement execution state, in which the measurement signal S1 is received by the fatigue determination unit 50 and measurement is performed, and a measurement non-execution state, in which the measurement signal S1 is not received by the fatigue determination unit 50 and measurement is not performed, based on the state of the measurement control signal S2. For example, the measurement switching unit 53 is in the measurement execution state when the measurement control signal S2 is transmitted from the switch 30 to the input unit 40, and in the measurement non-execution state when the measurement control signal S2 is not transmitted 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 orientation, and then presses the switch 30 to transition the determination device 1 to the measurement execution 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 when measurement is being performed.

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

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

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

[0025] Figure 4 is a perspective view of the probe. Figure 5 is a cross-sectional view of the probe. As shown in Figures 4 and 5, the probe 10 comprises a substantially cylindrical probe body 11 that contacts the surface of the bearing to be measured to detect the impedance of the bearing, a housing 13 having a sliding hole 14 extending axially inside the housing 13, the housing 13 which houses the probe body 11 positioned in the sliding hole 14 so as to be slidable in the axial direction, a butt portion 15 provided at the tip of the housing 13 and which can abut against the surface of the bearing to be measured, and a coil spring 17 positioned in the sliding hole 14 of the housing 13 as a biasing spring that biases the probe body 11 axially relative to the housing 13.

[0026] The housing 13 is an elongated cylindrical member extending in the axial direction (the longitudinal direction of the housing 13; the vertical direction in Figure 5). It is formed by connecting and integrating a substantially cylindrical base portion 13a and a substantially rectangular parallelepiped tip portion 13b, which are provided coaxially with each other, in the axial direction. The housing 13 is made of resin to suppress 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 its entire axial range, the inner diameter of the base portion 13a and the inner diameter of the tip portion 13b are the same. On the other hand, the outer diameter of the tip portion 13b is larger than the outer diameter of the base portion 13a, and 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. The user, for example, grasps the base portion 13a of the housing 13 and abuts the probe 10 against the surface to be measured. The user may grasp the tip 13b of the housing 13.

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

[0028] An elongated hole 13e is formed in one of the four outer circumferential surfaces 13d of the tip portion 13b of the housing 13, extending radially through that outer circumferential surface 13d. 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 the holder portion 22 of the probe body 11 (described later), are positioned in this elongated hole 13e. When the probe 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 then contact both axial ends (upper and lower ends in Figure 5) of the elongated hole 13e, restricting the sliding and limiting the axial movement distance of the probe body 11.

[0029] The probe body 11 comprises a probe section 21 and a holder section 22 that houses the probe section 21 and is slidable within a sliding hole 14 of the housing 13, as separate components. By separating the probe section 21 and the holder section 22 in this way, if either one is damaged, it can be replaced independently, thus reducing maintenance costs. The probe section 21 and the holder section 22 are made of resin to minimize any impact on impedance measurement.

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

[0031] The holder portion 22 is substantially cylindrical in shape and covers the probe portion 21 from the outer circumference. A pair of female screw holes 22a, 22a are formed in a part of the holder portion 22, spaced apart from each other in the axial direction, and pins 24 are screwed into each of these female screw 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 against the sliding hole 14, the probe portion 21 also slides integrally with it. The pair of pins 24, 24 protrude outward from the pair of female screw holes 22a, 22a, and these pins 24, 24 contact both axial ends of the elongated hole 13e, restricting sliding, thus limiting the axial movement distance of the probe body 11.

[0032] The probe body 11, consisting of a probe portion 21 and a holder portion 22, is positioned on the tip side of the sliding hole 14. On the other hand, a coil spring 17 is positioned on the base side of the sliding hole 14. The coil spring 17 extends axially so as to contact the lid portion 16 fixed to the housing 13 and the probe body 11. As a result, the probe body 11 is biased toward the tip side relative to the housing 13 by the coil spring 17.

[0033] In this embodiment, the coil spring 17 abuts against the holder portion 22 located on the outer circumference of the probe body 11. Therefore, by setting the outer diameter of the coil spring 17 to be approximately equal to the inner diameter of the sliding hole 14, the coil spring 17 can be guided by the sliding hole 14, thereby suppressing buckling of the coil spring 17 and stabilizing 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 body 11 extends through this gap. Because the cable 25 is positioned in the dead space on the inner diameter side of the coil spring 17 in this way, it contributes to miniaturizing the probe 10.

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

[0036] As shown in Figures 4 to 9, the tip 13b of the housing 13, which is roughly rectangular in shape, is provided with abutment portion 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 shape of the raceway surface 61 is arbitrary and may be cylindrical, for example. In particular, as shown in Figures 7 and 9, the shape of the abutment portion 15 when viewed from the axial direction is preferably rectangular, and in the illustrated example, it is square.

[0037] The abutment portion 15 has four projections 26 that protrude in the axial direction and are all the same shape. As shown in Figure 9, the projections 26 are approximately rectangular parallelepipeds, and the shape of the tip surface 26a of each projection 26 is rectangular. The four projections 26 are positioned at the vertices of the rectangle of the abutment portion 15. Furthermore, viewed from the axial direction, each of the four projections 26 is located at the vertex of a rectangle R centered on the central axis O1 of the probe body 11. In Figure 9, rectangle R is a square indicated by a dashed line, and it is formed by connecting the centers of the tip surfaces 26a of the four projections 26. Therefore, the four projections 26 are The rectangles R are positioned at equidistant locations from the central axis O1 and are also arranged at equal intervals in the circumferential direction relative to the central axis O1. Note that the rectangle R does not necessarily have to be a square; for example, it may be a rectangle. Furthermore, it is preferable that the rectangle R is similar in shape to the rectangle of the abutment portion 15.

[0038] As shown in Figures 6 to 9, during measurement, it is necessary to maintain the correct orientation in which the probe 10 is perpendicular to the raceway surface 61 of the outer ring 60. Therefore, the user ensures 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 concave spherical raceway surface 61 at their outermost corners 26b, which are furthest from the central axis O1 of the probe 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 body 11 can be kept perpendicular to the raceway surface 61, and stable measurement results can be obtained.

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

[0041] Furthermore, if the raceway surface 61 is a cylindrical shape concentric with the central axis O2 of the outer ring 60, it is necessary to maintain the correct orientation in which the probe 10 is perpendicular to the raceway surface 61 during measurement. In this case, as shown in Figure 9, the central axis O1 of the probe body 11 and the central axis O2 of the outer ring 60 are perpendicular, two sides r1 and r2 of the four sides constituting the rectangle R that are parallel to each other are parallel to the central axis O2 of the outer ring 60, and the other two sides r3 and r4 of the four sides constituting the rectangle R that are parallel to each other are perpendicular to the central axis O2 of the outer ring 60. Then, the pair of protrusions 26, 26 on one side in the circumferential direction (upper side in Figure 9) are spaced apart with respect to the direction of the central axis O2 of the outer ring 60, and similarly, the pair of protrusions 26, 26 on the other side in the circumferential direction (lower side in Figure 9) are also spaced apart with respect to the direction of the central axis O2 of the outer ring 60. Note that the points where the four protrusions 26 contact the raceway surface 61 are different from when the raceway surface 61 is a concave sphere. If the raceway surface 61 is cylindrical, the four protrusions 26 contact the raceway surface 61 at their circumferential outer edges 26d, including the outer corners 26b.

[0042] Next, we will describe the case where the raceway surface 71 formed on the outer circumferential surface of the inner ring 70 is measured. Figure 10 is a cross-sectional view showing the probe in contact with the raceway surface of the inner ring perpendicularly. Figure 11 is a view in the direction of arrow XI in Figure 10. Figure 12 is a cross-sectional view taken along the line XII-XII in Figure 11. Figure 13 is a cross-sectional view taken along the line XIII-XIII in Figure 11. Figure 14 is an enlarged view of the probe in Figure 11. Figure 15 is a partially enlarged view of Figure 10.

[0043] In the illustrated example, the outer circumferential surface of the inner ring 70 has two rows of raceway surfaces 71, 71 formed thereon. These raceway surfaces 71 are convex curved surfaces. The shape of the raceway surfaces 71 is arbitrary and may be cylindrical, for example. As shown in Figures 10 to 15, during measurement, it is necessary to maintain the correct orientation in which the probe 10 is perpendicular to the raceway surfaces 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 contact the raceway surfaces 71 of the inner ring 70. Specifically, as shown in Figures 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 sides r1 and r2 of the four sides constituting the rectangle R that are parallel to each other are parallel to the normal direction O4 of the contact angle α, and the other two sides r3 and r4 of the four sides constituting the rectangle R that are parallel to each other 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 explained with reference to Figure 15. In Figure 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 direction of the contact angle. The contact angle α is defined as the "nominal contact angle" described in the Japanese Industrial Standard JIS B 0104-1991 "Rolling Bearing Terminology," and is the angle formed by the 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, and is the direction of the force applied to the inner ring 70 from the rolling element (not shown). The normal direction O4 of the contact angle α is the direction that passes through the raceway surface 71 and is perpendicular to the contact angle direction O5. When the probe 10 is in the correct position 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] In this way, when the four protrusions 26 are brought into contact with the raceway surface 71, as shown in Figure 14, a pair of protrusions 26 are positioned on each side in the circumferential direction, straddling the direction O4 normal to the contact angle α. The pair of protrusions 26, 26 on one side in the circumferential direction (upper side in Figure 14) are spaced apart with respect to the direction O4 normal to the contact angle α, and similarly, the pair of protrusions 26, 26 on the other side in the circumferential direction (lower side in Figure 14) are spaced apart with respect to the direction O4 normal to the contact angle α of the inner ring 70.

[0046] The four protrusions 26 then contact the convex curved raceway surface 71 at their inner corners 26c. The inner corners 26c are the corners of the tip surface 26a of the protrusion 26 that are located outward with respect to the normal direction O4 of the contact angle α, and inward 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 body 11 can be kept 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 wobbling of the probe 10 being held is eliminated and the position of the probe 10 has stabilized. The user then presses the switch 30 to start acquiring the measurement signal S1, and the fatigue level or remaining life of the bearing is determined.

[0048] Even when the raceway surface 71 is a cylindrical shape concentric with the central axis O3 of the inner ring 70, it is necessary to maintain the correct orientation in which the probe 10 is perpendicular to the raceway surface 71 during measurement. In this case, although not specifically shown in the figures, the central axis O1 of the probe body 11 and the central axis O3 of the inner ring 70 should be perpendicular, two sides r1 and r2 of the four sides constituting the rectangle R that are parallel to each other should be parallel to the central axis O3 of the inner ring 70, and the other two sides r3 and r4 of the four sides constituting the rectangle R that are parallel to each other should be perpendicular to the central axis O3 of the inner ring 70. Furthermore, the pair of protrusions 26, 26 on one side in the circumferential direction (upper side of Figure 14) should be spaced apart with respect to the central axis O3 of the inner ring 70, and similarly, the pair of protrusions 26, 26 on the other side in the circumferential direction (lower side of Figure 14) should also be spaced apart with respect to the central axis O3 of the inner ring 70. Note that the points where the four protrusions 26 contact the raceway surface 71 are different from when the raceway surface 71 is a convex sphere. If the raceway surface 71 is cylindrical, the four protrusions 26 contact the raceway surface 61 at their circumferential inner edges 26e (see Figure 14), including the inner corners 26c.

[0049] In the illustrated example, the shape of the abutment portion 15, as viewed from the axial direction, is rectangular, and the four protrusions 26 are positioned at the vertices of the rectangle of the abutment portion 15. Therefore, the four protrusions 26 can be provided on the abutment portion 15 in a space-efficient manner, and the distance between adjacent protrusions 26 can be increased to stabilize the posture of the probe 10.

[0050] Furthermore, 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, circular for ease of manufacturing.

[0051] Furthermore, in the illustrated example, the shape of the tip surface 26a of the projection 26, as viewed from the axial direction, was rectangular. This allows the probe 10 to maintain a stable position when the surface to be measured 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 projections 26 into contact with the raceway surface 61. When the surface to be measured is the raceway surface 71 of the inner ring 70, which is a convex curved surface, the probe 10 can maintain a stable position by bringing the inner corners 26c of each of the four projections 26 into contact with the surface to be measured. In addition, although not specifically shown, when the surface to be measured is a flat surface, the probe 10 can maintain a stable position by bringing the entire tip surface 26a of the four projections 26 into contact with the surface to be measured.

[0052] Furthermore, the shape of the tip surface 26a of the projection 26 as viewed from the axial direction is not limited to a rectangle, but may be any shape, for example, it may be circular for ease of manufacturing.

[0053] In the illustrated example, the projection 26 is integrally provided with the abutment portion 15, but the projection 26 may be a separate pin from the abutment portion 15. In this case, the method of fixing the pin constituting the projection 26 is arbitrary, but examples include fixing by bonding it to the abutment portion 15, or fixing by press-fitting or screwing it into a hole formed in the abutment portion 15. By making the projection 26 a separate component in this way, it can be replaced if the projection 26 is damaged or worn. Furthermore, it is possible to replace it with an appropriate projection 26 for different measurement target surfaces according to their shape, roughness, and other characteristics.

[0054] Furthermore, the present invention is not limited to the embodiments described above, and can be modified, improved, etc., as appropriate.

[0055] As described above, the following matters are disclosed in this specification: (1) A probe that induces eddy currents in a bearing by applying an alternating magnetic field and detects the impedance of the bearing, A switch that transmits a measurement control signal to switch the start and end of acquiring the impedance measurement signal detected by the probe, Based on the impedance of the bearing, a fatigue determination unit for determining the fatigue degree or remaining life of the bearing is provided. A determination device comprising, The fatigue determination unit is, A map storage unit that stores a determination map including the relationship between the impedance characteristics of the bearing and the fatigue degree 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, In the measurement execution state, a data holding unit holds the measurement signal, An impedance characteristic calculation unit calculates the impedance characteristics of the bearing based on the held measurement signal, 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, Equipped with, The aforementioned probe A substantially columnar probe body that contacts the surface of the bearing to be measured and detects the impedance of the bearing, A housing having a sliding hole extending in the axial direction inside, the housing slidably housing the probe body positioned in the sliding hole in the axial direction, An abutment portion provided at the tip of the housing and capable of abutting against the surface of the bearing to be measured, A biasing spring is positioned in the sliding hole of the housing and biases the probe body axially relative to the housing, Equipped with, The aforementioned abutment portion has four projections that protrude in the axial direction, Viewed from the axial direction, each of the four protrusions is located at the vertex of a rectangle centered on the central axis of the probe body. Judgment device. (2) When viewed from the axial direction, the shape of the abutment portion is rectangular, and the four protrusions are positioned at the vertices of the rectangle of the abutment portion. (1) The determination device described above. (3) When viewed from the axial direction, the shape of the abutment portion is circular. (1) The determination device described above. (4) When viewed from the axial direction, the shape of the tip surface of the projection is rectangular. A determination device as described in any one of (1) to (3). (5) When viewed from the axial direction, the tip surface of the projection is circular in shape. A determination device as described in any one of (1) to (3). (6) The projection is a pin separate from the abutment and is fixed to the abutment. A determination device as described in any one of (1) to (5). (7) The probe body is A probe section having a coil, The holder portion houses the probe portion and is slidable within the sliding hole of the housing, It is provided separately. A determination device as described in any one of (1) to (6). (8) The biasing spring is a coil spring. The coil spring biases the holder portion of the probe body. (7) The determination device described above. (9) The probe body is equipped with a cable for extracting the measurement signal, The cable passes through the inner diameter side of the coil spring, (8) The determination device described above.

[0056] This application is based on Japanese Patent Application No. 2024-023325 filed on February 20, 2024, and its contents are incorporated herein by reference. [Explanation of symbols]

[0057] 1 Judgment device 10 probes 11 Probe body 13 Housing 13a base 13b Tip 13c Step section 13d Outer surface 13e long hole 14 Sliding hole 14a Opening at the tip 14b Base opening 15. Assault Section 17. Coil spring (biasing spring) 21 Probe section 22 Holder part 22a Female threaded hole 24 pins 25 Cables 26 Protrusion 26a Tip surface 26b Outer corner 26c inner corner 26d Outer edge in the circumferential direction 26e Circumferential inner side 30 switches 40 Input section 50 Fatigue determination unit 51 Map memory unit 53 Measurement switching section 55 Data storage unit 57 Impedance characteristic calculation unit 58 Display section 59 Judgment section 60 Outer ring (bearing) 61. Track surface (surface to be measured) 70 Inner ring (bearing) 71. Track surface (surface to be measured) O1 Probe body central axis O2 Outer ring central axis O3 Inner ring center axis O4 Normal direction of the contact angle O5 contact angle direction

Claims

1. A probe that induces eddy currents in a bearing by applying an alternating magnetic field and detects the impedance of the bearing, A switch that transmits a measurement control signal to switch the start and end of acquiring the impedance measurement signal detected by the probe, Based on the impedance of the bearing, a fatigue determination unit for determining the fatigue degree or remaining life of the bearing is provided. A determination device comprising, The fatigue determination unit is, A map storage unit that stores a determination map including the relationship between the impedance characteristics of the bearing and the fatigue degree 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, In the measurement execution state, a data holding unit holds the measurement signal, An impedance characteristic calculation unit calculates the impedance characteristics of the bearing based on the held measurement signal, 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, Equipped with, The aforementioned probe A substantially columnar probe body that contacts the surface of the bearing to be measured and detects the impedance of the bearing, A housing having a sliding hole extending in the axial direction inside, the housing slidably accommodates the probe body positioned in the sliding hole in the axial direction, An abutment portion provided at the tip of the housing and capable of abutting against the surface of the bearing to be measured, A biasing spring is positioned in the sliding hole of the housing and biases the probe body axially relative to the housing, Equipped with, The aforementioned abutment portion has four projections that protrude in the axial direction, Viewed from the axial direction, each of the four protrusions is located at the vertex of a rectangle centered on the central axis of the probe body. When viewed from the axial direction, the shape of the tip surface of the projection is rectangular. Judgment device.

2. Viewed from the axial direction, the shape of the abutment portion is rectangular, and the four protrusions are positioned at the vertices of the rectangle of the abutment portion. The determination device according to claim 1.

3. When viewed from the axial direction, the shape of the abutment portion is circular. The determination device according to claim 1.

4. The aforementioned projection is a pin separate from the abutment portion and is fixed to the abutment portion. The determination device according to claim 1.

5. The probe body is A probe section having a coil, The probe portion is housed inside, and the holder portion is slidable within the sliding hole of the housing, It is provided separately. The determination device according to claim 1.

6. The biasing spring is a coil spring. The coil spring biases the holder portion of the probe body. The determination device according to claim 5.

7. The probe body is equipped with a cable for extracting the measurement signal. The cable passes through the inner diameter side of the coil spring, The determination device according to claim 6.

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