JP2015025713A - Frictional wear phenomenon analysis device of friction member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device capable of analyzing a frictional wear phenomenon of a friction member using AE, and capable of simultaneously analyzing a plurality of frictional wear phenomena.SOLUTION: A frictional wear phenomenon analysis device 1 can ensure the frictional contact of a friction member 2 and sensitively detect AE generated in the friction member 2 since the frictional wear phenomenon analysis device 1 includes: a pressing device 6 which brings the friction member 2 into a frictional contact with a rotating member 10; and an energizing member 5 which makes an AE sensor 4 contact with the friction member 2, in a separate system.

Description

  The present invention relates to an apparatus for analyzing a frictional wear phenomenon of a friction member that is in frictional contact with a rotating rotating member.

  Brake pads (friction members) used in automotive disc brakes must satisfy various performances such as effectiveness, life, and NV (Noise Vibration) at the same time. ing. For this reason, although the frictional wear phenomenon of the brake pad is complicated, various performances can be improved by clarifying this frictional wear phenomenon and reflecting it in the blending of various raw materials.

  For example, Patent Document 1 describes an apparatus for analyzing wear of a friction member. This apparatus presses a friction member against a rotating rotating member, and analyzes wear of the friction member based on measured acoustic emission (hereinafter referred to as AE) and the measurement position. Patent Document 2 describes a device that detects wear of a stem nut used as a friction member in an electric valve. This device detects AE generated from a stem nut and outputs an AE signal, calculates AE energy based on an AE signal having a frequency component due to wear in the AE signal, and based on an accumulated amount of AE energy. The wear state of the stem nut is determined.

JP-A-6-308017 JP 2007-3299 A

  Since the above-described Patent Document 1 does not disclose specific usage examples or analysis examples of the measured AE, it is difficult to analyze the wear of the friction member with the apparatus described in Patent Document 1. In addition, since the apparatus described in Patent Document 2 determines the wear state of the friction member only by the magnitude of the AE signal having a specific frequency component, a plurality of friction wear phenomena cannot be analyzed simultaneously.

  The present invention has been made in view of such circumstances, and an apparatus capable of analyzing the friction wear phenomenon of the friction member using AE and simultaneously analyzing a plurality of friction wear phenomena. The purpose is to provide.

  The invention according to claim 1 is an apparatus for analyzing a frictional wear phenomenon of a friction member that is in frictional contact with a rotating rotating member, the fixing member fixing the friction member, and the frictional contact of the rotating rotating member. An AE sensor that detects an AE generated in the friction member and outputs an AE signal; and a sensor unit of the AE sensor that is disposed between the fixing member and the AE sensor so as to contact the friction member. A biasing member that biases the sensor toward the friction member; and a pressing device that presses the fixing member toward the rotation member in order to cause the friction member to frictionally contact the rotation member.

  According to the first aspect of the present invention, the frictional wear phenomenon analyzing apparatus includes the pressing device that frictionally contacts the friction member with the rotating member and the biasing member that contacts the friction member with the AE sensor. Thus, it is possible to detect the AE generated in the friction member with high sensitivity by reliably performing the frictional contact of the friction member.

  According to a second aspect of the present invention, the friction member includes a recess into which the sensor unit side of the AE sensor is inserted on a surface opposite to a contact surface that frictionally contacts the rotating member.

  According to the second aspect of the present invention, since the sensor portion of the AE sensor is disposed at a position close to the contact surface of the friction member that frictionally contacts the rotating member, attenuation inside the friction member is suppressed. AE can be reliably detected. In addition, since it is not necessary to make the entire friction member thin, it is easy to fix the friction member to the fixing member, and it is possible to prevent the friction member from being damaged due to frictional contact.

The invention according to claim 3 is that a heat insulating member is disposed between the sensor portion of the AE sensor and the friction member.
According to the third aspect of the present invention, the frictional heat generated on the contact surface of the friction member that is in frictional contact with the rotating member is less likely to be transferred to the sensor portion of the AE sensor by the heat insulating member. Can be prevented.

The invention according to claim 4 is that the urging member is a member having elasticity.
According to the fourth aspect of the present invention, since the sensor portion of the AE sensor is urged and brought into close contact with the contact member by the urging member with an appropriate force, AE can be detected with high sensitivity. Moreover, since an excessive force is not applied to the AE sensor, it is possible to prevent the sensor portion from being damaged.
The invention according to claim 5 is that the recess is formed such that a thickness from a bottom surface of the recess to a contact surface with the rotating member is 11 mm or less.
According to the invention described in claim 5, it is possible to suppress the attenuation of AE inside the friction member.

The invention according to claim 6 is provided with a phenomenon identifying device that identifies a property of the frictional wear phenomenon based on a frequency of an AE signal output from the AE sensor.
According to the invention described in claim 6, since analysis in a wide frequency band is possible, the properties of a plurality of friction and wear phenomena can be specified by one analysis, and the analysis time can be greatly shortened. Can do.
The invention according to claim 7 is that the phenomenon specifying device includes a display device for displaying the property of the specified friction and wear phenomenon.
According to the seventh aspect of the present invention, the operator can visually recognize the properties of the plurality of frictional wear phenomena of the friction member, so that the analysis work efficiency can be greatly improved.

In the invention according to claim 8, the phenomenon identifying device performs frequency analysis on the AE signal after a change point of an average value or an integral value for every predetermined time interval of the AE signal output from the AE sensor appears. When the peak value of the AE signal of 300 kHz or less appears, it is determined that the coating layer is broken or dropped, and when the peak value of the AE signal whose frequency exceeds 300 kHz appears, it is specified that the adhesive wear has occurred. That is.
According to the invention described in claim 8, since the change point of the average value or integral value of the AE signal for each predetermined time interval is first determined, it is possible to perform analysis for a long time while suppressing an increase in data capacity. Become.

It is a figure which shows schematic structure of the friction wear phenomenon analyzer of the friction member of this embodiment. It is a top view of a friction member. It is a side view of a friction member. It is a figure which shows the intensity ratio of the AE signal output by detecting AE generated in the friction member when the pad thickness of the friction member is changed. It is a block block diagram which shows an example of the phenomenon specific apparatus of a friction wear phenomenon analyzer. It is a block block diagram which shows another example of the phenomenon specific apparatus of a friction wear phenomenon analyzer. It is a flowchart for demonstrating the analysis operation | movement of a friction wear phenomenon analyzer. FIG. 5 is a diagram showing a change with time of an average value or an integral value at predetermined time intervals of an AE signal displayed on the display device of the phenomenon identifying device of FIG. 4. FIG. 5 is a diagram illustrating a result of frequency analysis of an AE signal after a change point of an average value or an integral value for each predetermined time interval of the AE signal displayed on the display device of the phenomenon specifying device of FIG. 4 appears. It is a figure which shows the time-dependent change of the average value or integral value for every predetermined time interval of the AE signal from which the frequency displayed on the display apparatus of the phenomenon specific device of FIG. It is a figure which shows schematic structure of the friction wear phenomenon analyzer of the friction member of another form.

(1. Friction and wear phenomenon analyzer for friction members)
A schematic configuration of a frictional wear phenomenon analyzing apparatus for a friction member according to an embodiment of the present invention will be described with reference to the drawings. As shown in FIG. 1, the frictional wear phenomenon analyzing apparatus 1 for the frictional member 1 is based on the AE generated from the frictional member 2 that is in frictional contact with the rotating member 10 that is rotated by driving the motor 11. It is a device that analyzes phenomena. That is, AE is a phenomenon in which elastic energy stored in a solid is released as an elastic wave when the solid is deformed or destroyed. Since the AE occurs because the frictional wear phenomenon of the friction member 2 is accompanied by a kind of deformation / destruction phenomenon, the frictional wear phenomenon of the friction member 2 can be analyzed from the characteristics of the AE signal.

  The frictional wear phenomenon analyzing apparatus 1 uses a fixing member 3 for fixing the friction member 2, an AE sensor 4 for detecting AE generated in the friction member 2, and a sensor portion 41 on the tip side of the AE sensor 4 as the friction member 2. In order to make contact, the biasing member 5 that biases the AE sensor 4 toward the friction member 2, and the pressing device 6 that presses the fixing member 3 toward the rotation member 10 in order to frictionally contact the friction member 2 with the rotation member 10. And a control device 7 that controls the pressing of the pressing device 6, inputs an AE signal from the AE sensor 4, and analyzes the frictional wear phenomenon of the friction member 2.

  The frictional wear phenomenon analyzing apparatus 1 having the above-described configuration includes a pressing device 6 that frictionally contacts the friction member 2 with the rotating member 10 and a biasing member 5 that contacts the friction member 2 with the AE sensor 4 in separate systems. Therefore, it is possible to detect the AE generated in the friction member 2 with high sensitivity by reliably performing the frictional contact of the friction member 2.

  As the friction member 2, a test piece cut out in a rectangular plate shape from a brake pad of a disc brake can be used. As shown in FIGS. 2A and 2B, the friction member 2 includes a contact member 21 that contacts the rotating member, a reinforcement member 22 made of metal that reinforces the contact member 21, and a coupling that couples the contact member 21 and the reinforcement member 22. The member 23 is laminated. The coupling member 23 also has a heat insulating effect that suppresses transmission of heat generated by the contact member 21. The friction member 2 has a depth extending from the surface of the reinforcing member 22 to the middle of the contact member 21 through the coupling member 23 and is inserted into the sensor portion 41 side of the AE sensor 4. Is provided.

  When the AE generated on the contact surface 21a of the contact member 21 passes through the contact member 21, there is a possibility that the transmission strength of the AE is reduced and cannot be detected by the AE sensor 4, but the friction member 2 is provided with a recess 24. Thus, by reducing the pad thickness t from the contact surface 21a of the contact member 21 to the bottom surface 24a of the recess 24, it is possible to detect the AE sensor 4 while suppressing a decrease in AE transmission intensity. However, if the pad thickness t is too thin, the contact member 21 may be destroyed when frictionally contacting the rotating member 10, and the pad thickness t is preferably 2 mm or more. Therefore, an experiment for obtaining a limit value of the pad thickness t was performed.

  As shown in FIG. 3, when the pad thickness t is changed to 3 mm, 7 mm, and 11 mm, the AE signal when the AE generated in the friction member 2 is detected and output by the AE sensor 4 (center frequency: 1 MHz) Signal intensity ratio (= transmitted signal intensity / incident signal intensity) is 0.008 when the pad thickness t is 3 mm, 0.002 when the pad thickness t is 7 mm, and 0. When the pad thickness t is 11 mm. 0004. Since the signal intensity ratio needs to be about 0.0005, it has been found that the pad thickness t detectable by the AE sensor 4 is preferably 11 mm or less.

  As described above, the sensor unit 41 of the AE sensor 4 is disposed at a position close to the contact surface 21a of the contact member 21 that is in frictional contact with the rotating member 10, so that attenuation inside the contact member 21 is suppressed. The detected AE can be reliably detected. Further, since it is not necessary to make the entire friction member 2 thin, it is easy to fix the friction member 2 to the fixing member 3, and it is possible to prevent the friction member 2 from being damaged by frictional contact.

  As shown in FIG. 1, the fixing member 3 includes a rectangular parallelepiped receiving member 31 having a thickness smaller than that of the friction member 2, a substantially rectangular parallelepiped intermediate member 32, and a rectangular parallelepiped base. 33. The receiving member 31 is provided with a through hole 31a having a rectangular axial cross section into which the rectangular plate-like friction member 2 can be fitted. The intermediate member 32 is provided with a through hole 32a having a circular axial cross section through which the cylindrical AE sensor 4 can be inserted. The base 33 is provided with a bottomed hole 33a having a rectangular axial cross section into which one end side of the rectangular parallelepiped biasing member 5 can be inserted.

The AE sensor 4 is a general broadband (frequency characteristic: 0.1 MHz to 1 MHz) AE sensor in which a sensor unit 41 such as a piezoelectric element is provided on one end side of a cylindrical casing.
In this example, the urging member 5 is an elastic member made of a rectangular parallelepiped rubber or the like. Since the sensor portion 41 of the AE sensor 4 is urged by the urging member 5 and is brought into close contact with the contact member 21 with an appropriate force, AE can be detected with high sensitivity. Moreover, since an excessive force is not applied to the AE sensor 4, the sensor unit 41 can be prevented from being damaged. In addition, by providing a bolt penetrating from the pressing device 6 side of the base 33 toward the friction member 2 side as the urging member 5, the front end portion of this bolt is brought into contact with the rear end of the AE sensor 4 and the bolt is turned. The AE sensor 4 may be energized.

The pressing device 6 includes a pressure sensor 61 in this example, and an air cylinder that can be pressed with air pressure is used. A hydraulic cylinder that can be pressed with hydraulic pressure may be used as the pressing device 6.
The control device 7 receives a pressure signal from the pressure sensor 61, inputs a pressure control device 71 that controls pressurization / decompression of the pressing device 6, and an AE signal from the AE sensor 4, and causes frictional wear of the friction member 2. And a phenomenon specifying device 72 having a display device 73 for displaying the properties of the specified friction and wear phenomenon.

  As shown in FIG. 4, as an example of the phenomenon identifying device 72, the phenomenon identifying device 72A amplifies the AE signal from the AE sensor 4 by an amplifier 721, and eliminates the influence of mechanical vibration, for example, a frequency of 20 kHz or more. The filtered AE signal is amplified by the amplifier 723 and input to the AE signal calculation unit 724.

  Then, the AE signal calculation unit 724 obtains an average value obtained by averaging the envelope detection waveform of the AE signal at every predetermined time interval or an integral value obtained by performing the integration process, and displays the average value on the display device 73 to display the AE signal. When a change point at which the average value or integral value of the signal rises or fluctuates appears, an analysis start signal is output to the frequency analysis unit 725. The frequency analysis unit 725 obtains the frequency characteristic of the AE signal when a change point of the average value or the integral value of the AE signal appears and displays it on the display device 73. Specific processing of the AE signal calculation unit 724 and the frequency analysis unit 725 will be described later.

  Further, as shown in FIG. 5, as another example of the phenomenon identifying device 72, the phenomenon identifying device 72B amplifies the AE signal from the AE sensor 4 with an amplifier 721 and passes a frequency exceeding, for example, 300 kHz. The filtered AE signal is filtered by the filter 727a, amplified by the first amplifier 723a, input to the first AE signal calculation unit 724a, and filtered by the second bandpass filter 727b that passes a frequency of 300 kHz or less. The AE signal is amplified by the second amplifier 723b and input to the second AE signal calculation unit 724b.

  Then, the average value of the AE signal filtered to a frequency exceeding 300 kHz every predetermined time by the first AE signal calculation unit 724a is obtained, and the AE filtered to a frequency of 300 kHz or less by the second AE signal calculation unit 724b every predetermined time. The average value of the signals is obtained, and the average value of these AE signals is displayed on the display device 73 in an overlapping manner. In this way, by displaying the AE signal in an overlapped manner for each frequency, the operator can reliably identify a plurality of frictional wear phenomena of the friction member 2 by visual recognition. The specific processing of the first and second AE signal calculation units 724a and 724b will be described later.

  According to the phenomenon specifying device 72 as described above, since analysis in a wide frequency band is possible, the properties of a plurality of friction and wear phenomena can be specified by one analysis, and the analysis time is greatly shortened. be able to. In addition, since the change point of the average value or the integral value of the AE signal is first determined, it is possible to perform analysis for a long time while suppressing an increase in data capacity. Further, since the average value or integral value of the AE signal is obtained and displayed by the AE signal calculation unit 724, the operator can surely grasp the timing when the frictional wear phenomenon of the friction member 2 changes. In addition, since the frequency analysis unit 725 obtains and displays the frequency characteristics of the AE signal, the operator can visually recognize the properties of a plurality of frictional wear phenomena of the friction member 2 and greatly improve the analysis work efficiency. Can be made.

(2. Analysis operation of friction and wear phenomenon analyzer)
Next, the analysis operation of the frictional wear phenomenon analyzing apparatus 1 will be described with reference to the flowchart of FIG. First, as a preparatory work, the receiving member 31 is fixed to the intermediate member 32 with bolts, and the intermediate member 32 is fixed to the base 33 with bolts to assemble the fixing member 3. And the front-end | tip (sensor part 41) of the AE sensor 4 is inserted in the through-hole 32a of the intermediate member 32 from between the intermediate member 32 and the base 33, and the urging member 5 is inserted into the rear end of the AE sensor 4 and the base 33. Between the bottomed hole 33a. Next, while inserting the front-end | tip (sensor part 41) of the AE sensor 4 in the recessed part 24 of the friction member 2, the friction member 2 is inserted in the through-hole 31a of the member 31. FIG.

  Then, the friction member 2 is pressed from the contact member 21 side, the urging member 5 is elastically deformed, the reinforcing member 22 of the friction member 2 is brought into contact with the intermediate member 32, and the friction member 2 is fixed to the receiving member 31 with bolts. . As a result, the AE sensor 4 is urged toward the friction member 2 by the restoring force of the urging member 5, so that the sensor portion 41 is brought into contact with the bottom surface 24 a of the recess 24 of the friction member 2. Then, the base 33 is fixed to the cylinder rod 62 of the pressing device 6 with bolts. Thus, the setting of the friction member 2 in the frictional wear phenomenon analyzing apparatus 1 is completed (step S1).

Next, the pressure control device 71 of the control device 70 controls the pressing device 6 to bring the friction member 2 into frictional contact with the rotating member 10 rotating (step S2). The phenomenon specifying device 72 receives the AE signal from the AE sensor 4 and specifies the nature of the frictional wear phenomenon of the friction member 2 based on the frequency of the AE signal (step S3).
Here, in the case of the phenomenon specifying device 72A, the AE signal calculation unit 724 obtains an average value or integral value of the AE signal at a predetermined time interval and displays it on the display device 73, and the average value or integral value of the AE signal increases. Alternatively, when a changing point that fluctuates appears, an analysis start signal is output to the frequency analysis unit 725.

  Specifically, as shown in FIG. 7, the average value or the integral value of the AE signal rapidly increases at a certain time point ta, and at this time, an analysis start signal is output to the frequency analysis unit 725. The frequency analysis unit 725 obtains the frequency characteristic of the AE signal when the average value or the integral value of the AE signal rises and displays the frequency characteristic on the display device 73 to identify the property of the frictional wear phenomenon of the friction member 2.

  That is, as shown in FIG. 8, when a peak value pa of an AE signal having a frequency of 300 kHz or less or a harmonic having the signal as a fundamental wave appears, the contact surface 21a (friction coating) of the contact member 21 of the friction member 2 appears. Layer) is identified as having been destroyed or dropped. Further, when the peak value pb of the AE signal having a frequency exceeding 300 kHz appears, it is specified that adhesive wear has occurred on the contact surface 21a of the contact member 21 of the friction member 2. These frictional wear phenomena can be identified by observing the contact surface 21a of the contact member 21 of the friction member 2 with a laser microscope and observing the generated wear powder with a field emission scanning electron microscope.

  In the case of the phenomenon specifying device 72B, the first AE signal calculation unit 724a obtains an average value or an integral value of the AE signal filtered to a frequency exceeding 300 kHz for each predetermined time interval, and the second AE signal calculation unit 724b The average value or integral value of the AE signal filtered to a frequency of 300 kHz or less at every predetermined time interval is obtained, and the average value or integral value of these AE signals is displayed on the display device 73, and the frictional wear of the friction member 2 is obtained. Identify the nature of the phenomenon.

  Specifically, as shown in FIG. 9, when a peak value pa of an AE signal with a frequency of 300 kHz or less or a harmonic having the signal as a fundamental wave appears, the contact surface 21 a of the contact member 21 of the friction member 2. It is specified that the (friction coating layer) was broken or dropped. Further, when the peak value pb of the AE signal having a frequency exceeding 300 kHz appears, it is specified that adhesive wear has occurred on the contact surface 21a of the contact member 21 of the friction member 2. These frictional wear phenomena can be identified by observing the contact surface 21a of the contact member 21 of the friction member 2 with a laser microscope and observing the generated wear powder with a field emission scanning electron microscope.

(3. Another form of friction and wear phenomenon analyzer)
As shown in FIG. 10 corresponding to FIG. 1, the heat insulating member 8 may be arranged between the sensor portion 41 of the AE sensor 4 and the contact member 21 of the friction member 2. As the heat insulating member 8, quartz glass is preferable, but a material such as ceramics which has low thermal conductivity and hardly attenuates high frequency AE may be used. As a result, the frictional heat generated on the contact surface of the contact member 21 that is in frictional contact with the rotating member 10 is less likely to be transferred to the sensor portion 41 of the AE sensor 4 by the heat insulating member 8, thereby preventing damage to the AE sensor 4 due to heat. can do.

  In the above-described embodiment, the phenomenon specifying device 72B is configured to specify the properties of the two types of friction and wear phenomenon by the first AE signal calculation unit 724a and the second AE signal calculation unit 724b. It is good also as a structure which specifies the property of three or more types of friction wear phenomena by providing an AE calculating part.

1: friction wear phenomenon analysis device, 2: friction member, 3: fixed member, 4: AE sensor, 41: sensor unit, 5: biasing member, 6: pressing device, 7: control device, 71: pressure control device, 72, 72A, 72B: phenomenon identification device, 722: high-pass filter, 724: AE signal calculation unit, 725: frequency analysis unit, 724a: first AE signal calculation unit, 724b: second AE signal calculation unit, 727a: first Bandpass filter, 727b: second bandpass filter, 10: rotating member, 21: contact member, 21a: contact surface, 22: reinforcing member, 23: heat insulating member, 24: recessed portion, 24a: bottom surface, 31: receiving member, 31a: Through hole, 32: Intermediate member, 32a: Through hole, 33: Base, 33a: Bottomed hole

Claims (8)

An apparatus for analyzing a frictional wear phenomenon of a friction member that frictionally contacts a rotating member that rotates,
A fixing member for fixing the friction member;
An AE sensor that detects acoustic emission (AE) generated in the friction member in frictional contact with the rotating member and outputs an AE signal;
An urging member disposed between the fixed member and the AE sensor to urge the AE sensor toward the friction member in order to bring the sensor portion of the AE sensor into contact with the friction member;
A pressing device that presses the fixed member against the rotating member in order to frictionally contact the friction member with the rotating member;
An apparatus for analyzing frictional wear of a friction member. The friction member is
2. The frictional wear phenomenon analyzing apparatus for a friction member according to claim 1, further comprising a concave portion into which a sensor portion side of the AE sensor is inserted on a surface opposite to a contact surface in frictional contact with the rotating member.   The apparatus for analyzing a frictional wear phenomenon of a friction member according to claim 1 or 2, wherein a heat insulating member is disposed between the sensor portion of the AE sensor and the friction member.   The frictional wear phenomenon analysis device for a friction member according to any one of claims 1 to 3, wherein the biasing member is a member having elasticity.   The frictional wear phenomenon of the friction member according to any one of claims 2 to 4, wherein the concave portion is formed so that a thickness from a bottom surface of the concave portion to a contact surface with the rotating member is 11 m or less. Analysis device.   6. The friction wear phenomenon analysis device for a friction member according to claim 1, further comprising a phenomenon specifying device for specifying a property of the friction wear phenomenon based on a frequency of an AE signal output from the AE sensor.   The apparatus for analyzing a frictional wear phenomenon of a friction member according to claim 6, wherein the phenomenon specifying device includes a display device that displays a property of the specified frictional wear phenomenon.   The phenomenon identifying device analyzes the frequency of the AE signal after a change point of an average value or an integral value for each predetermined time interval of the AE signal output from the AE sensor appears, and peaks the AE signal having a frequency of 300 kHz or less. The friction according to claim 6 or 7, wherein when the value appears, it is specified that the coating layer is broken or dropped off, and when the peak value of the AE signal whose frequency exceeds 300 kHz appears, it is specified that adhesive wear occurs. Friction and wear phenomenon analysis device for members.

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