JP2002031623A - Inspecting apparatus for composite material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an inspecting apparatus for composite materials which can detect not only internal crazes and blisters of the composite materials such as a brake pad having a back plate and a brake lining, etc., but joint failures of members of different materials. SOLUTION: A transmission method utilizing both of a pair of probes 41 and a reflection method utilizing only one probe 41 are changed over by a switching part 61. Ultrasonic waveforms are detected in each method, thereby judging whether the product is good or not.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite material inspection apparatus, and more particularly to a composite material suitable for inspection of a brake pad having a back plate and a friction material, which is used for, for example, a vehicle brake, particularly a disk brake. To an inspection device.

[0002]

2. Description of the Related Art A brake pad used in a conventional disc brake is formed as a composite material in which a friction material is fixed to a steel plate back plate. The resin in the raw material is cross-linked and polymerized by transferring to a mold of a hot press in which is set, and the friction material is integrated with the back plate.

[0003] In the manufacturing process of a brake pad, organic components such as resin and moisture are gasified in the manufacturing process, and if the gas is insufficiently vented, cracks and swelling are generated in the product.

[0004] Therefore, a unique ultrasonic wave is given to the object to be inspected,
An inspection apparatus described in, for example, Japanese Patent Application Laid-Open No. 10-252785 has been proposed as a method for comparing the waveform obtained thereby with a prescribed one to determine the presence or absence of cracks, swelling and the like of the friction material.

FIG. 5 is an enlarged view of a main part of the conventional inspection apparatus described in the above-mentioned publication. The inspection apparatus 1 includes a disk-shaped feed member 7 having an arc-shaped guide surface 5 having substantially the same curvature as a brake lining for a drum brake to be inspected 3, and a feed claw formed on the feed member 7. 9 and probes 11 and 13.

The probes 11 and 13 have rotating rollers 15 and 17 which come into contact with the device under test 3, and these are biased by a spring 19 so as to be able to advance and retreat with respect to the device under test 3. Therefore, even when inspecting the inspected object 3 having a different shape, the probes 11 and 13 can always maintain the contact state with the inspected object 3 following the change in the shape of the inspected object 3. Has become. The test object 3 is sent along the feed member 7 and is inspected by the probes 11 and 13 for the presence or absence of cracks and swelling. This was expected to enable accurate and easy inspection.

[0007]

However, in the above-described conventional inspection apparatus, the probes 11, 13 are pressed from both sides of the device under test 3, and ultrasonic waves are applied from one of the probes to the device under test 3. Is transmitted and received by the other probe, and the presence or absence of cracks or swelling inside the object 3 is determined from the received waveform at that time. In the inspection according to the above, in the case where the inspected body 3 is a composite material such as a brake pad having a back plate and a friction material, there is a problem that it is not possible to sufficiently inspect a bonding failure between members (that is, interfaces) of different materials. .

[0008] The present invention has been made in view of the above circumstances, and not only defects due to cracks and swelling inside a composite material such as a brake pad having a back plate and a friction material, but also the joining between members of different materials. It is an object of the present invention to provide a composite inspection apparatus capable of detecting a defect.

[0009]

In order to achieve the above object, a composite material inspection apparatus according to the present invention comprises a pair of probes arranged at opposite positions on both sides of the composite material. In a composite material inspection apparatus that transmits ultrasonic waves to determine the quality of the composite material from the waveform of a received signal, a transmission type inspection using both of the pair of probes, and only one of the probes is used. And a switching unit for switching to a reflection-type inspection using the method.

[0010] In the composite material inspection apparatus, when the transmission type inspection is selected, an ultrasonic wave is transmitted from one probe to the composite material, and the ultrasonic wave is received by the other probe. The presence or absence of cracks or swelling inside the composite is determined from the received waveform. On the other hand, if the reflection type inspection is selected, one probe transmits and receives ultrasonic waves to and from the composite material, and based on the received waveform at that time, the presence or absence of bonding failure between different members of the composite material Is determined.

Therefore, according to the present apparatus, not only defects due to cracks and swelling inside a composite material such as a brake pad having a back plate and a friction material, but also defective bonding between members made of different materials can be performed with high accuracy. Can be detected.

[0012]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a side view showing a schematic configuration of a composite material inspection apparatus according to an embodiment of the present invention. Composite material inspection apparatus 5 according to this embodiment
1 is an inspection of a brake pad having a back plate and a friction material, which is used for a brake of a vehicle, particularly a disc brake, having a back plate and a friction material, for checking for cracks and swelling and for checking for a bonding failure between the back plate and the friction material. Is what you can do.

The apparatus frame (not shown) is provided with a bed 21 having a substantially horizontal moving surface 21a. At one end of the bed 21 (the right end in FIG. 1), there is provided a supply unit 25 for stacking and storing untested brake pads 23, which are composite materials, with a back plate described below facing down.

The brake pad 23 has a structure in which a friction material 27 is fixed to a back plate 29. The material of the friction material, which is composed of a fiber material, a filler and a binder, is compressed and preformed, and then the material is compressed. The resin in the raw material is cross-linked and polymerized by putting it into a hot press mold with
It is manufactured by integrating the friction material 27 with the back plate 29. In the center of the friction material 27 in the pad transfer direction according to the present embodiment, a drain / radiation groove 27a that functions when the brake pad 23 is used is formed. In this embodiment, the groove 27a is used for detecting the position of the brake pad 23.

A driving cylinder (for example, a hydraulic cylinder) 31 as a moving means is provided at one end of the supply section 25. The working fluid of the drive cylinder 31 may be either air or oil. The moving means is constituted by a rack and a pinion in addition to the drive cylinder 31, or
A configuration using a ball screw may be used. Drive cylinder 3
1 is arranged horizontally, and the drive shaft 31a moves on the moving surface 21a,
It is driven to expand and contract toward the supply unit 25.

Openings 33a and 33b are formed below the pair of side walls of the supply unit 25 in contact with the moving surface 21a. The opening 33a is formed so that at least the dimension in the height direction is larger than the thickness of the brake pad 23 and the dimension in the width direction (the direction orthogonal to the paper surface of FIG. 1) is larger than the width of the brake pad 23. On the other hand, the opening 33b is formed in such a size that at least the drive shaft 31a of the drive cylinder 31 can be inserted and withdrawn.

Accordingly, when the drive cylinder 31 is driven and the drive shaft 31a is extended, the drive shaft 31a enters the opening 33b, and the brake pad 23 laminated at the lowermost stage is moved to the opening 33a on the opposite side. And temporarily stop the drive. The brake pad 23 pushed out from the opening 33a is further transferred on the moving surface 21a to the left end in FIG. 1 by re-driving the drive shaft 31a. When the brake pad 23 is moved to a predetermined position, the drive shaft 31a
Retreats with the brake pad 23 left at that position, and withdraws from the supply unit 25. As a result, the second brake pad 23 from the bottom is arranged at the lowermost position, which is the take-out standby position.

A probe insertion hole 35 is formed at a predetermined position of the bed 21 where the brake pad 23 is sent from the opening 33a. The probe insertion hole 35 exposes most of the lower surface (the lower surface in FIG. 1) of the back plate 29 of the brake pad 23. A plurality of probe drive cylinders 37 are fixed vertically above and below the device frame (not shown) with the probe insertion hole 35 interposed therebetween. A total of four probe drive cylinders 37 according to the present embodiment are arranged one above the other. The upper or lower probe drive cylinder 37 is
One is located on the upstream side in the pad transfer direction, and the other is located on the downstream side in the pad transfer direction, with respect to a.

The apparatus frame is provided with a position detecting sensor (for example, an infrared sensor) 39 as detecting means. The position detection sensor 39 is provided in the groove 2 of the brake pad 23.
By detecting 7a, the presence or absence of a brake pad is detected. Then, the above-described drive cylinder 31
Is driven and controlled by a control device (not shown) based on the position information from the position detection sensor 39. The drive of the probe drive cylinder 37 is controlled by the control device based on the detection information from the position detection sensor 39.

A probe 41 is fixedly mounted on the tip of the drive shaft of the probe drive cylinder 37, and the probe 41 transmits and receives ultrasonic waves. The probe 41 appropriately selects one of two systems: a system in which one transmits and receives ultrasonic waves (reflection system), and a system in which one of the pair emits ultrasonic waves and the other receives it (transmission system). I can do it. In this embodiment, each probe 41 can transmit and receive ultrasonic waves.

When an ultrasonic wave is applied to an object to be inspected and flaw detection is performed based on a vibration waveform detected therefrom, it is desirable that the detected vibration waveform is stable in order to facilitate determination. This detected vibration waveform is stabilized at a frequency unique to the inspection object. Elements that determine the natural frequency include the material of the friction material 27, the mass and structure of the brake pad 23, and the like. Among them, the structure of the brake pad 23 has a large influence on the determination.

The applicant has examined the optimum frequency of the brake pad 23 in the laminated structure in which the friction material 27 is fixed to the back plate 29. As a result, it was found that 0.2 to 0.3 MHz is an optimal frequency at which a stable determination can be obtained for a delicate determination. Therefore, the ultrasonic waves transmitted and received by the probe 41 are set in the band of 0.2 to 0.3 MHz.

The probe 41 is provided with a pressure sensor 43 as pressure detecting means. The probe 41 is pressed against the brake pad 23, which is an object to be inspected, by vertically moving the probe drive cylinder 37. The pressure sensor 43 can detect the pressing pressure applied to the brake pad 23 at this time.

The pressing force of the probe drive cylinder 37 against the brake pad 23 is driven and controlled by a control device (not shown). The control device detects a signal from the pressure sensor 43 and controls the probe drive cylinder 37 by, for example, feedback control so that the detected pressure becomes a constant value.
Control. That is, the probe 41 is always pressed against the brake pads 23 having different shapes with a constant pressure. On the pad contact surface of the probe 41,
A close contact member 45 preferably made of a gel-like substance (silicon rubber or the like) is fixed. When the probe 41 is pressed against the object to be inspected, the close contact member 45 absorbs irregularities on the surface of the object to be inspected, and makes the probe 41 closely contact with the surface of the object without gaps.

From the output of each probe 41, the brake pad 2
As shown in the functional block diagram of FIG. 2, the detection unit 60 that determines pass / fail of the third unit 3 includes a switching unit 61 that is a switching unit that switches a pair of opposed probes 41 between a transmission system and a reflection system.
A control unit 62 that supplies a switching signal to the switching unit 61, a processing unit 63 that captures both outputs of the pair of opposing probes 41 and performs signal waveform detection processing in a transmission system, and a pair of opposing probes A processing unit 64 that takes in only one output of the child 41 and performs a signal waveform detection process by a reflection method, and a processing result (a shape of a signal waveform) of the processing unit 63 determines whether or not the inside of the brake pad 23 is cracked or swollen. An evaluation judging section 65 for judging, an evaluation judging section 66 for judging the presence or absence of a joint failure between the friction material 27 of the brake pad 23 and the back plate 29 based on the processing result (shape of the signal waveform) of the processing section 64; The display unit 67 is configured to display a determination result of the determination unit 65 and a determination result of the evaluation determination unit 66.

The switching from the transmission system to the reflection system or from the reflection system to the transmission system is automatically performed by the control unit 62, but may be manually performed. When switching from the transmission system to the reflection system, the control unit 62 causes the control device to connect the probe 41 on the opposite side (the friction material 27) to the probe 41 on the side that emits ultrasonic waves and the brake pad 23.
Instruct you to move away from it. Needless to say, if the probe 41 on the side opposite to the side that emits ultrasonic waves is not separated from the brake pad 23 in the case of the reflection method, the light is transmitted without being reflected. The control device includes a control unit 6
When receiving an instruction to release the probe 41 from the probe 2, the probe 4
1 is controlled so as to be separated from the brake pad 23.

In the transmission system, as shown in FIG. 3A, a pair of opposing probes 41 are used, and a brake is applied from one of the probes 41 (in this example, the lower probe). Pad 2
3 and the other probe 41 (in this example, the upper probe) receives the ultrasonic wave. The change in the phase and amplitude of the received waveform at that time causes a crack inside the brake pad 23 to change. 7
The presence or absence of 0 or swelling 71 is determined. On the other hand, in the reflection method,
As shown in FIG. 3B, a pair of opposing probes 41
Is transmitted to and received from the brake pad 23 by using one of the above (in this example, the lower probe).
Connection 72 between friction material 27 and back plate 29 constituting
Is determined.

In this embodiment, since there are two pairs of probes 41, a time lag as shown in FIG. 4, for example, is given to the ultrasonic wave generation of each probe 41. Thereby, the ultrasonic waves emitted from the respective probes 41 do not interfere with each other. Therefore, a quick and highly accurate flaw detection inspection can be performed using a plurality of probes 41 simultaneously contacting one brake pad 23.

Next, the operation of the brake pad inspection device 51 thus configured will be described. When the inspection is started, the drive cylinder 31 is driven, the drive shaft 31a enters the opening 33b of the supply unit 25, and the brake pad 23, which is the inspection object stacked at the lowermost stage, is moved to the opening on the opposite side. Push out from the part 33a. Extruded brake pad 23
Is detected by the position detection sensor 39, the control device puts the drive cylinder 31 into a standby state in which the drive cylinder 31 is temporarily stopped. Thereby, the brake pad 23 is arranged so as to coincide with the probe insertion hole 35.

Next, the probe drive cylinder 37 is driven in response to a signal from the control device, and the probe 41 is pressed against the front and back surfaces of the brake pad 23. The control device detects a signal from the pressure sensor 43 and controls the drive cylinder 31 so that the detected pressure becomes a constant value. Thereby, each probe 41 is provided with a different brake pad 2.
3 is always pressed with a constant pressure.

Next, in a state where the transmission system is switched to the transmission system, an ultrasonic wave is emitted from one probe 41 of each pair of the probes 41, and the ultrasonic wave is transmitted by the other probe 41 of the same pair. Obtain as a waveform. At this time, each probe 41
The transmission and reception of the ultrasonic waves are controlled in different time zones.
After the detection by the transmission system, the system is automatically switched from the transmission system to the reflection system. When the mode is switched to the reflection type, the probe 41 on the opposite side to the probe 41 that emits each pair of ultrasonic waves is separated from the brake pad 23, and then the ultrasonic wave is emitted from the probe 41 that emits the ultrasonic wave. And the same probe 4
1 to obtain an ultrasonic waveform.

After the transmission and reception of the ultrasonic wave and the processing in each system are performed, the quality of the product is determined, and the result is displayed. When the quality of the product is determined, the probe drive cylinder 37 is driven, and the probe 41 is separated from the brake pad 23. Probe 41 and brake pad 23
When the contact with is released, the control device receives this release signal and drives the drive cylinder 31 again. Drive cylinder 3
When 1 is driven again and the drive shaft 31a is extended again, the brake pad 23 is transported further to the left from the probe insertion hole 35 and discharged from the measurement position. In this case, non-defective products and defective products are separated and discharged. Thereafter, the drive shaft 31a of the drive cylinder 31 retreats and returns to the initial state.

Then, it is confirmed by the position detection sensor 39 that the brake pad 23 is not present.
Are in a standby state, and the inspection process of one inspection object is completed. When the inspection is started again, the drive shaft 31a of the drive cylinder 31 is extended, and the same operation is repeated.

As described above, according to the above-described brake pad inspection apparatus 51, the transmission system using both the pair of probes 41 and the reflection system using only one of the probes are switched to each other. The ultrasonic wave is detected by the method to judge the quality of the product, and the result is displayed, so that not only the inside of the brake pad 23 is cracked or swollen, but also the friction material 27 is used.
It is also possible to detect a joint failure between the back plate 29.

In the present embodiment, the brake pad 23, which is a composite material, is used for inspection. However, in addition to the above, peeling of a metal weld, peeling of a bimetal joint, and peeling of a concrete wall may be performed. Of course, it can be used for detecting peeling or the like.

In the present embodiment, the transmission system evaluation / judgment unit 65, the reflection system evaluation / judgment unit 66 and the display unit 67 of the detection unit 60 are replaced by a computer such as a personal computer.
It is also possible to adopt a configuration in which the transmission system is automatically switched from the transmission system to the reflection system in accordance with a pre-installed program, and the evaluation judgment is performed by comparing with a reference value set for each system.

In the present embodiment, the detection unit 60 is prepared for each pair of the probes 41. However, it is of course possible to prepare a detection unit common to each pair of the probes 41. It is better to do so in terms of cost.

[0038]

As described above, according to the present invention, by using both the transmission system and the reflection system, the presence or absence of cracks or swelling inside a composite material such as a brake pad having a back plate and a friction material is determined. In addition, it is possible to detect a poor connection between members made of different materials.

[Brief description of the drawings]

FIG. 1 is a side view showing a schematic configuration of a composite material inspection apparatus according to an embodiment of the present invention.

FIG. 2 is a block diagram illustrating a schematic configuration of a detection unit of the inspection device of FIG.

FIG. 3 is a diagram for explaining an operation of a detection unit in FIG. 2;

FIG. 4 is a time chart showing an ultrasonic generation time of each probe of the inspection apparatus of FIG. 1;

FIG. 5 is an enlarged view of a main part of a conventional inspection device.

[Explanation of symbols]

 23 Brake pad 41 Probe 61 Switching unit 62 Control unit 63, 64 Processing unit 65, 66 Evaluation judgment unit 67 Display unit

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hiroyuki Soma 19-5 Nihonbashi Koamicho, Chuo-ku, Tokyo Inside Akebono Brake Industry Co., Ltd. (72) Inventor Takao Maki 19th Nihonbashi Koamicho, Chuo-ku, Tokyo No. 5 Akebono Brake Industry Co., Ltd. F-term (reference) 2G047 AA05 AB05 AB07 AC05 BA01 BA03 BC07 GA19

Claims (1)

[Claims] 1. A composite material in which a pair of probes are arranged at positions facing each other on both sides of a composite material, an ultrasonic wave is transmitted to the composite material, and the quality of the composite material is determined based on a waveform of a received signal. A composite material comprising: a switching unit that switches between a transmission type inspection using both of the pair of probes and a reflection type inspection using only one of the probes. Inspection equipment.