Dynamic characteristic test system and dynamic characteristic test method of weather strip

Abstract

To provide a test system and a test method which are capable of simply and highly precisely evaluating the dynamic characteristic of a weather strip.SOLUTION: A dynamic characteristic test system 1 of a weather strip adds vibration to a test piece 40 simulating a vehicle fitting state, and evaluates the dynamic characteristic of the strip. The system comprises: a first jig 10 in which the test piece 40 is fitted to a fitting part simulating a cross-sectional shape of a weather strip fitting part; a second jig 20 which is oppositely arranged to the first jig 10 such that an abutting part simulating a cross-sectional shape of the weather strip abutting part and the fitting part sandwich the test piece 40; an impedance head 9; a vibration exciter 3 which adds vibration of a designated frequency range to the second jig 20; and PC 30. A length dimension of the second jig 20 is set while maintaining a cross-sectional shape of the abutting part such that its natural frequency is deviated from the designated frequency range.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a test system and a test method for evaluating the dynamic characteristics of a weatherstrip.

Background Art

[0002] For example, in order to accurately measure the characteristics of in-vehicle parts made of rubber such as EPDM (ethylene propylene diene rubber) during driving, it has been conventionally known to conduct a dynamic characteristic test under the same conditions as an actual vehicle.

[0003] In such a dynamic characteristic test, if the resonance frequency of the jig for attaching the in-vehicle part to the shaker is not made to deviate from the frequency range to be measured, it becomes difficult to accurately measure the dynamic characteristics of the in-vehicle part before and after the resonance frequency of the jig.

[0004] Therefore, for example, Patent Document 1 discloses a dynamic characteristic measuring device including a cylindrical resonance jig as a jig for attaching a vibration isolator rubber (including a mass-attached vibration isolator rubber, a liquid-filled vibration isolator rubber, etc.) to a shaker.

[0005] Although no detailed explanation is described, according to the one in this Patent Document 1, by making the resonance jig cylindrical, it is said that an arbitrary resonance frequency can be given to the resonance jig.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] Incidentally, vibration-absorbing and suppressing vibration rubber mounts are often attached to rigid brackets or the like via bolts or the like due to their function. Therefore, as in Patent Document 1, even when using a cylindrical jig in a dynamic characteristic test, it is possible to easily reproduce the same conditions as in an actual vehicle.

[0008] However, even for in-vehicle parts made of rubber, for weather strips attached to doors or the like to protect the interior from rain, wind, and noise, they are attached to the vehicle body by sandwiching protrusions formed on the vehicle body or the like, or the protrusions formed on the doors or the like come into contact. Therefore, it is difficult to reproduce the same conditions as in an actual vehicle in a dynamic characteristic test using a simple-shaped jig such as a cylindrical shape. In other words, for weather strips, there is a problem that it is difficult to reproduce the same conditions as in an actual vehicle while suppressing the resonance of the jig in the frequency range to be measured.

[0009] For this reason, for weather strips, the material characteristics are only substituted by a dynamic viscoelasticity measurement test on a test piece, and the shape characteristics are measured under static load. The material characteristics and shape characteristics are only separated as performance indicators, and the evaluation of dynamic characteristics assuming driving is not currently being performed.

[0010] However, in recent years, as countermeasures against low-frequency noise and low-frequency vibration in vehicles, such as drumming noise, stuffy noise, and mid-frequency road noise, attention has been paid, and it is desired to accurately evaluate the dynamic characteristics of weather strips during driving.

[0011] The present invention has been made in view of such points, and an object thereof is to provide a test system and a test method capable of easily and accurately evaluating the dynamic characteristics of weather strips.

Means for Solving the Problems

[0012] In order to achieve the above object, in the weatherstrip dynamic characteristic test system according to the present invention, in order to simulate the state of being mounted on a vehicle, while maintaining the cross-sectional shape of the portion of the jig that contacts the weatherstrip, the natural frequency of the jig is removed from the frequency range to be measured.

[0013] Specifically, the present invention is directed to a weatherstrip dynamic characteristic test system that vibrates a specimen obtained by cutting a weatherstrip in a direction perpendicular to its longitudinal direction, simulating the state of being mounted on a vehicle, and evaluates its dynamic characteristics.

[0014] And this dynamic characteristic test system has a mounting portion that simulates the cross-sectional shape of the weatherstrip mounting portion in either the door or the door opening, and a first jig to which the specimen is attached to the mounting portion, and a contact portion that simulates the cross-sectional shape of the weatherstrip contact portion in the other of the door and the door opening, and a second jig that is arranged opposite to the first jig so as to sandwich the specimen between the contact portion and the mounting portion, an impedance head that detects the force required to vibrate the second jig and the acceleration at that time, a vibrator that can apply vibrations in a specified frequency range to the second jig in a direction opposite to the first jig via the impedance head, and a dynamic characteristic calculation means that calculates the dynamic characteristics of the weatherstrip based on the detection value detected by the impedance head. The second jig is characterized in that at least one of the dimension, material, and overall shape in the direction perpendicular to the cross-section of the contact portion is set while maintaining the cross-sectional shape of the contact portion so that its natural frequency is outside the specified frequency range.

[0015] According to this configuration, by applying vibrations in a specified frequency range to the second jig while pressing the contact portion that simulates the cross-sectional shape of the weatherstrip contact portion of the door opening (or the door) against the specimen attached to the mounting portion that simulates the cross-sectional shape of the weatherstrip mounting portion of the door (or the door opening), the dynamic characteristics of the weatherstrip in a state similar to the in-vehicle state can be evaluated.

[0016] Here, examples of the "specified frequency range" include 50 Hz or less (drumming noise), 50 to 400 Hz (muffled sound), 200 to 500 Hz (mid-frequency road noise), etc. However, if the second jig resonates within the "specified frequency range", it becomes difficult to obtain (evaluate) the dynamic characteristics of the weatherstrip.

[0017] In this regard, in this configuration, in order to simulate the state of being mounted on a vehicle, at least one of the dimensions, material, and overall shape of the second jig is set so that the natural frequency of the second jig is outside the "specified frequency range" while maintaining the cross-sectional shape of the contact portion. Therefore, it is possible to suppress the second jig from resonating within the "specified frequency range", and thereby, it is possible to accurately evaluate the dynamic characteristics of the weatherstrip.

[0018] Moreover, even if changes are made to the dimensions of the second jig according to the "specified frequency range", while maintaining the cross-sectional shape of the contact portion, due to the particularity of the weatherstrip that the cross-sectional shape to be extruded is constant, by adjusting the cutting length of the weatherstrip as a test specimen according to the dimensions of the second jig, etc., tests corresponding to various frequency ranges can be easily performed.

[0019] As described above, according to the dynamic characteristic test system for the weatherstrip according to the present invention, it is possible to easily and accurately evaluate the dynamic characteristics of the weatherstrip in a state similar to the in-vehicle state.

[0020] Also, in the above dynamic characteristic test system, the first jig, the second jig, the impedance head, and the vibrator may be arranged in this order from bottom to top.

[0021] According to this configuration, since the first jig, the second jig, the impedance head, and the vibrator are arranged in this order from bottom to top, in other words, it is not necessary to consider the self-weight of the second jig, and mass cancellation can be minimized, so it becomes possible to evaluate the dynamic characteristics of the weatherstrip with higher accuracy.

[0022] Furthermore, the present invention is directed to a method for testing the dynamic characteristics of a weatherstrip in which vibration is applied to a specimen obtained by cutting a weatherstrip in a direction perpendicular to its longitudinal direction, simulating the state of being mounted on a vehicle, and evaluating its dynamic characteristics.

[0023] And this method for testing dynamic characteristics has a mounting portion that mimics the cross-sectional shape of the weatherstrip mounting portion in either the door or the door opening, and a first jig to which the specimen is attached to the mounting portion, and a contact portion that mimics the cross-sectional shape of the weatherstrip contact portion in the other of the door and the door opening, and a second jig that is arranged opposite to the first jig so as to sandwich the specimen between the contact portion and the mounting portion, an impedance head that detects the force required to vibrate the second jig and the acceleration at that time, and a vibrator that can apply vibration in a specified frequency range to the second jig in a direction opposite to the first jig via the impedance head. As the second jig, at least one of the dimension, material, and overall shape in a direction orthogonal to the cross-section of the contact portion is set so that its natural frequency is outside the specified frequency range while maintaining the cross-sectional shape of the contact portion, and based on the detection value detected by the impedance head, the dynamic characteristics of the weatherstrip are calculated.

[0024] According to this configuration, as described above, by adjusting the cutting length of the weatherstrip as the specimen according to the dimensions of the second jig and the like, tests corresponding to various frequency ranges can be easily performed, and thereby, the dynamic characteristics of the weatherstrip can be evaluated simply and accurately.

[0025] In addition, in the above dynamic characteristic test method, the first jig, the second jig, the impedance head, and the vibrator may be used by arranging them in this order from bottom to top.

[0026] According to this configuration, similarly to the above, it is not necessary to consider the self-weight of the second jig, and mass cancellation can be minimized, so that the dynamic characteristics of the weatherstrip can be evaluated with higher accuracy.

Effect of the Invention

[0027] As described above, according to the dynamic characteristic test system and the dynamic characteristic test method for a weatherstrip according to the present invention, the dynamic characteristics of the weatherstrip can be easily and accurately evaluated.

Brief Description of the Drawings

[0028]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Embodiments for Carrying Out the Invention

[0029] Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

[0030] -Dynamic Characteristic Test System- FIG. 1 is a schematic diagram schematically showing a dynamic characteristic test system 1 of a weatherstrip 50 (see FIG. 2) according to the present embodiment. This dynamic characteristic test system 1 applies vibration to a specimen 40 simulating a state of being mounted on a vehicle 60 (see FIG. 2) to evaluate the dynamic characteristics of the weatherstrip 50. In the present embodiment, the “specimen 40” refers to a long weatherstrip 50 formed by extrusion molding and cut in a direction perpendicular to the longitudinal direction so as to have a length suitable for the dynamic characteristic test.

[0031] FIG. 2 is a diagram schematically showing the weatherstrip 50 to be tested. FIG. 2(a) is a side view of a vehicle 60 on which the weatherstrip 50 is mounted, and FIG. 2(b) is a cross-sectional view taken along the arrow of line b-b in FIG. 2(a). In the vehicle 60 shown in FIG. 2(a), as shown in FIG. 2(b), an outer peripheral side weatherstrip 51 attached to the outer peripheral edge of the door 63 and contacting the body 61 when the door 63 is closed, and an inner peripheral side weatherstrip 53 attached along the door opening of the body 61 and contacting the outer peripheral edge of the door 63 when the door 63 is closed are provided, and a double seal structure is adopted.

[0032] In the present embodiment, for both the outer peripheral side weatherstrip 51 and the inner peripheral side weatherstrip 53, dynamic characteristic tests are performed by simulating the state of being mounted on the vehicle 60 with respect to two locations: the roof portion indicated by the reference symbol Rf in FIG. 2(a) and the hinge portion indicated by the reference symbol Hg in FIG. 2(a).

[0033] As shown in FIG. 1, the dynamic characteristic test system 1 includes a first jig 10, a second jig 20, an impedance head 9, a vibrator 3, a power amplifier 5, a generator / analyzer 7, and a personal computer 30. In this dynamic characteristic test system 1, the first jig 10, the second jig 20, the impedance head 9, and the vibrator 3 are arranged in this order from bottom to top.

[0034] FIG. 3 is a diagram schematically showing a state in which the doors 63 of the test specimens 41, 43 and the jigs 11, 13, 21, 23 simulating the hinge part Hg of the vehicle 60 are closed. FIG. 3(a) is a diagram showing the test specimen 41 simulating the outer peripheral weather strip attached to the door 63 side, and FIG. 3(b) is a diagram showing the test specimen 43 simulating the inner peripheral weather strip attached to the body 61 side. Further, FIG. 4 is a diagram schematically showing a state in which the doors 63 of the test specimens 45, 47 and the jigs 15, 17, 25, 27 simulating the roof part Rf of the vehicle 60 are closed. FIG. 4(a) is a diagram showing the test specimen 45 simulating the outer peripheral weather strip 51 attached to the door 63 side, and FIG. 4(b) is a diagram showing the test specimen 47 simulating the inner peripheral weather strip 53 attached to the body 61 side.

[0035] In the following, when not particularly distinguished, the test specimens 41, 43, 45, 47 are collectively referred to as "test specimen 40", the first jigs 11, 13, 15, 17 are collectively referred to as "first jig 10", and the second jigs 21, 23, 25, 27 are collectively referred to as "second jig 20".

[0036] The first jig 10 has attachment parts 11a, 13a, 15a, 17a simulating the cross-sectional shapes of the weather strip attachment parts 61a, 63a in either the door 63 or the door opening (body 61), and is configured such that the test specimen 40 is attached to the attachment parts 11a, 13a, 15a, 17a. The material of the first jig 10 is not particularly limited, and for example, it may be made of aluminum or resin. Further, the first jig 10 may have a solid structure or a hollow structure.

[0037] In contrast, the second jig 20 has contact portions 21a, 23a, 25a, 27a that mimic the cross-sectional shapes of the weather strip contact portions 61b, 63b on either the door 63 or the other of the door opening (body 61). The second jig 20 is arranged opposite to the first jig 10 so that the test specimen 40 is sandwiched between the contact portions 21a, 23a, 25a, 27a and the mounting portions 11a, 13a, 15a, 17a. The material of the second jig 20 is not particularly limited. For example, it may be made of aluminum or resin. Also, the second jig 20 may have a solid structure or a hollow structure.

[0038] More specifically, as shown in FIG. 3(a), the first jig 11 has a mounting portion 11a that mimics the cross-sectional shape of the weather strip mounting portion at the hinge portion Hg on the door 63. The test specimen 41 is attached to the mounting portion 11a. On the other hand, the second jig 21 has a contact portion 21a that mimics the cross-sectional shape of the weather strip contact portion at the hinge portion Hg on the body 61. The second jig 21 is arranged opposite to the first jig 11 so that the test specimen 41 is sandwiched between the contact portion 21a and the mounting portion 11a.

[0039] Also, as shown in FIG. 3(b), the first jig 13 has a mounting portion 13a that mimics the cross-sectional shape of the weather strip mounting portion at the hinge portion Hg on the body 61. The test specimen 43 is attached to the mounting portion 13a. On the other hand, the second jig 23 has a contact portion 23a that mimics the cross-sectional shape of the weather strip contact portion at the hinge portion Hg on the door 63. The second jig 23 is arranged opposite to the first jig 13 so that the test specimen 43 is sandwiched between the contact portion 23a and the mounting portion 13a.

[0040] Furthermore, as shown in FIG. 4(a), the first jig 15 has a mounting portion 15a that mimics the cross-sectional shape of the weather strip mounting portion 63a at the roof portion Rf on the door 63. The test specimen 45 is attached to the mounting portion 15a. On the other hand, the second jig 25 has a contact portion 25a that mimics the cross-sectional shape of the weather strip contact portion 61b at the roof portion Rf on the body 61. The second jig 25 is arranged opposite to the first jig 15 so that the test specimen 45 is sandwiched between the contact portion 25a and the mounting portion 15a.

[0041] Also, as shown in FIG. 4(b), the first jig 17 has an attachment portion 17a that mimics the cross-sectional shape of the weather strip attachment portion 61a at the roof portion Rf in the body 61. A test specimen 47 is attached to the attachment portion 17a. On the other hand, the second jig 27 has a contact portion 27a that mimics the cross-sectional shape of the weather strip contact portion 63b at the roof portion Rf in the door 63. The second jig 27 is arranged opposite to the first jig 17 so that the test specimen 47 is sandwiched between the contact portion 27a and the attachment portion 17a.

[0042] As can be seen by comparing FIG. 2(b) showing the roof portion Rf with FIGS. 4(a) and (b), in the dynamic characteristic test system 1 of the present embodiment, by devising the shapes of the first jigs 15 and 17 and the second jigs 25 and 27, the test specimen 40 during the dynamic characteristic test can be made to be in a state close to the state of being mounted on the vehicle 60. As a result, it is possible to accurately measure the dynamic characteristics of the weather strip 50 during running. Although not shown, this is the same for the hinge portion Hg.

[0043] The impedance head 9 has an integrated structure of a force gauge and an acceleration sensor, and is configured to detect the force required to vibrate the second jig 20 and the acceleration at that time. More specifically, as shown in FIG. 1, the impedance head 9 has its upper end mechanically connected to the vibrator 3, while its lower end is mechanically connected to the second jig 20. By applying vibration to the object through the impedance head 9, two electrical signals proportional to the stress and acceleration in the axial direction (the vertical direction in the present embodiment) are output to the generator / analyzer 7.

[0044] The vibrator 3 is configured to generate vibrations by reciprocating a drive coil (not shown) installed in a magnetic field by passing an alternating current through the drive coil. Through the impedance head 9, the vibrator 3 applies vibrations in a specified frequency range to the second jig 20 in the direction facing the first jig 10 (the vertical direction in this embodiment). The vibrator 3 is electrically connected to the power amplifier 5 and is also electrically connected to the generator / analyzer 7 via the power amplifier 5. A current signal such as a sine wave generated by the generator is amplified by the power amplifier 5 and introduced into the vibrator 3, enabling vibration to be performed at an arbitrary frequency controlled / instructed by the personal computer 30 via the generator / analyzer 7.

[0045] The personal computer 30 (hereinafter also referred to as "PC 30") includes a CPU (Central Processing Unit), a ROM (Read Only Memory) that stores processing programs, a RAM (Random Access Memory) that temporarily stores data, etc., and is configured to perform various operations and controls by causing the CPU, ROM, RAM, etc. to cooperate. Specifically, the PC 30 is electrically connected to the generator / analyzer 7, outputs a command for generating a current signal such as a sine wave to the generator section, and calculates the dynamic characteristics of the weather strip 50 based on the detection value detected by the impedance head 9 analyzed by the analyzer section. Thus, in relation to the claims, the analyzer section in the PC 30 and the generator / analyzer 7 of this embodiment corresponds to the "dynamic characteristic calculation means for calculating the dynamic characteristics of the weather strip based on the detection value detected by the impedance head" referred to in the present invention.

[0046] FIG. 5 is a block diagram schematically showing the main part of the dynamic characteristic test system 1. In the dynamic characteristic test system 1 configured as described above, when the PC 30 issues a command to the generator section in the generator / analyzer 7 as indicated by the dashed arrow A in FIG. 5, for example, the generator section generates a SweptSine wave (a sine wave whose frequency changes from 0 Hz to the upper limit frequency within the time length of one FFT operation), and outputs an electrical signal representing such a SweptSine wave to the power amplifier 5 as indicated by the dashed arrow B in FIG. 5. The power amplifier 5 amplifies the input electrical signal representing the SweptSine wave, and outputs the amplified electrical signal to the shaker 3 as indicated by the dashed arrow C in FIG. 5.

[0047] The shaker 3 vibrates the second jig 20 while changing the frequency and amplitude according to the amplified electrical signal. The impedance head 9 senses the vibration by the shaker 3 as indicated by the dashed arrow D in FIG. 5 during the vibration of the second jig 20. The force and acceleration sensed (detected) by the impedance head 9 are transmitted to the generator / analyzer 7 as indicated by the dashed arrow E in FIG. 5, and are analyzed and converted into data by the analyzer section in the generator / analyzer 7. Then, the analysis result converted into data by the analyzer section is taken into the PC 30 as indicated by the dashed arrow F in FIG. 5.

[0048] -Calculation method of dynamic characteristics- In the present embodiment, the generator / analyzer 7 and the PC 30 calculate the storage elastic modulus E', the loss elastic modulus E", and the loss coefficient η as the dynamic characteristics of the weatherstrip 50. More specifically, the generator / analyzer 7 and the PC 30 measure the transfer function (frequency response function: Frequency Response Function (FRF)) at the mobility (H: resonance peak) to obtain the dynamic elastic modulus (complex elastic modulus) E * (m 2 / N), and obtain the dynamic elastic modulus E *It is configured to calculate the storage elastic modulus E', the loss elastic modulus E", and the loss coefficient η based on the following. Hereinafter, this calculation method will be briefly described. Note that the method described here is merely an example, and the calculation method of the dynamic characteristics is not limited to this.

[0049] First, the dynamic elastic modulus E * represents the dynamic viscoelastic characteristics by focusing on the phase lag of the stress-strain characteristics of the viscoelastic material as the phase angle of the complex elastic modulus. Since it is defined as the ratio of the "vibrating stress" obtained by expanding the elastic modulus (Young's modulus) to the strain generated thereby, it can be expressed by the following formula (1).

[0050]

Equation

[0051] Thus, since the dynamic characteristics test performed in this embodiment is a compression test, the stress σ and the strain ε can be expressed by the following formulas (2) and (3), respectively.

[0052]

Equation

[0053]

Equation

[0054] Therefore, by substituting formulas (2) and (3) into formula (1) and arranging them, the dynamic elastic modulus E * can be expressed by the following formula (4).

[0055]

Equation

[0056] Note that the cross-sectional area A perpendicular to the vertical load F applied to the specimen 40 can be calculated as follows. FIG. 6 is a diagram schematically explaining the cross-sectional area A perpendicular to the vertical load F applied to the specimen 40 in the method for calculating dynamic characteristics. FIG. 6(a) shows a state where the vertical load F is not applied to the specimen 40, and FIG. 6(b) shows a state where the vertical load F is applied to the specimen 40. As shown in FIG. 6(a), when vibration is applied to the specimen 40 having a length L and a hollow seal portion 49 with a diameter D via the second jig 20, the specimen 40 deforms as shown in FIG. 6(b). In this case, the contact area A' between the specimen 40 and the second jig 20 can be expressed as the product of the width D' of the specimen 40 in contact with the second jig 20 and the length L as shown in FIG. 6(b), and this contact area A' can be regarded as the cross-sectional area A perpendicular to the vertical load F applied to the specimen 40.

[0057] Here, the dynamic stiffness is a characteristic value representing the difficulty of deformation of an object with respect to a dynamic force, and since it is the reciprocal of the compliance G (m / N) indicating the tendency of the object to move under the influence when an external force is applied, the dynamic stiffness 1 / G (N / m) can be expressed by the following formula (5).

[0058]

Equation

[0059] Therefore, by substituting Equation (5) into Equation (4), the dynamic elastic modulus E * can be expressed by the following formula (6).

[0060]

Equation

[0061] On the other hand, mobility is a transfer function indicating the ease of movement of an object and is defined as (velocity / force). Therefore, the mobility H at the resonance peak can be expressed by the following formula (7).

[0062]

Mathematics

[0063] Also, since the transfer function generally consists of gain and phase as elements, it can be represented using complex numbers. Mobility H, which is one of the transfer functions, can also be represented by its real part and imaginary part as shown in the following equation (8).

[0064]

Mathematics

[0065] Here, since the dynamic displacement is the result of integrating the velocity once, the equation (5) representing the dynamic stiffness 1 / G can be transformed as follows. By substituting equation (7) into this, the dynamic stiffness 1 / G can be expressed by equation (9) using mobility H.

[0066]

Mathematics

[0067] Then, by substituting equation (8) into equation (9), the dynamic stiffness 1 / G can be expressed by the following equation (10).

[0068]

Mathematics

[0069] By substituting the thus-derived equation (10) into equation (6), the dynamic elastic modulus E * can be expressed by the following equation (11).

[0070]

Mathematics

[0071] Here, the storage elastic modulus E' representing the elasticity of the object is the real part of the dynamic elastic modulus E * and the loss elastic modulus E'' representing the viscosity of the object is the dynamic elastic modulus E* It is the imaginary part in [description], and since the loss coefficient η representing the degree of contribution of viscosity is the ratio of the loss elastic modulus E” to the storage elastic modulus E’, the storage elastic modulus E’, the loss elastic modulus E”, and the loss coefficient η can be expressed by the following formulas (12), (13), and (14), respectively.

[0072]

Number

[0073]

Number

[0074]

Number

[0075] As described above, since the impedance head 9 can detect acceleration / force (accelerance), by performing single integration on this, a graph (reference) representing velocity / force (mobility) can be obtained. By reading “a” from the gain and “b” from the phase respectively and substituting them into formulas (12), (13), and (14), as shown in FIGS. 8 to 13 described later, it becomes possible to obtain the storage elastic modulus E’, the loss elastic modulus E”, and the loss coefficient η.

[0076] -Mass cancellation- FIG. 7 is a diagram schematically explaining mass cancellation in the dynamic characteristic test system 1. FIG. 7(a) shows the main part of a conventional dynamic characteristic test system, and FIG. 7(b) shows the main part of the dynamic characteristic test system 1 of the present embodiment. Here, the “conventional dynamic characteristic test system” refers to a test system capable of measuring the dynamic characteristics of, for example, vibration isolators.

[0077] In a conventional dynamic characteristic test system, as shown in Fig. 7(a), a vibrator 103, an impedance head 109, a second jig 120, and a first jig 110 are arranged in this order from bottom to top, and the vibrator 103 is configured to apply vibration to a specimen 140 sandwiched between the first jig 110 and the second jig 120. Thus, in the conventional dynamic characteristic test system, since the weight of the second jig 120 acts on the impedance head 109, when analyzing the dynamic characteristics of the specimen 140, it is necessary to perform a so-called mass cancellation to cancel the load corresponding to the weight of the second jig 120.

[0078] In this regard, in the dynamic characteristic test system 1 according to the present embodiment, as shown in Fig. 7(b), since the first jig 10, the second jig 20, the impedance head 9, and the vibrator 3 are arranged in this order from bottom to top, in other words, since the vibrator 3 is installed upside down compared to the conventional dynamic characteristic test system, it is not necessary to consider the self-weight of the second jig 20. Thus, since it is not necessary to consider the self-weight of the second jig 20 and the mass cancellation can be minimized, it becomes possible to evaluate the dynamic characteristics of the weatherstrip 50 with higher accuracy.

[0079] - Setting of jig - Fig. 8 is a graph schematically illustrating the change in the measurable frequency range of dynamic characteristics due to the change in the dimensions of the second jigs 20', 20". In Figs. 8(a) and (b), the symbol Ac (thick solid line) indicates the acceleration (acceleration / force) when the specimen 40 is attached.

[0080] When the second jig 20' with a length dimension of 100 mm is used, as shown in Fig. 8(a), the second jig 20' resonates at 282 Hz. Therefore, when the second jig 20' is used, it becomes difficult to evaluate the dynamic characteristics of the weatherstrip 50 depending on the frequency range (specified frequency range) for which evaluation is desired.

[0081] Specifically, among the low-frequency noise and low-frequency vibration in vehicle 60, which has recently attracted attention for countermeasures, for example, there are drumming noises below 50 Hz, stuffy noises between 50 and 400 Hz, mid-frequency road noises between 200 and 500 Hz, and the like. Therefore, when using the second jig 20' in which the frequency range exceeding 282 Hz becomes unmeasurable, although the dynamic characteristics of the weatherstrip 50 can be evaluated for drumming noises, it becomes difficult to evaluate the dynamic characteristics of the weatherstrip 50 for stuffy noises and mid-frequency road noises.

[0082] Therefore, in the dynamic characteristic test system 1 according to the present embodiment, while maintaining the cross-sectional shapes of the contact portions 21a, 23a, 25a, and 27a, at least one of the dimension (length dimension) in the direction orthogonal to the cross-section of the contact portions 21a, 23a, 25a, and 27a, the material, and the overall shape is set so that the natural frequency of the second jig 20 is outside the specified frequency range. The second jig 20 is used.

[0083] More specifically, "resonance" is a phenomenon in which when vibrations equal to the natural frequency are applied to a vibrating body from the outside, the amplitude of the vibrations increases. However, if the natural frequency of the second jig 20 is outside the specified frequency range, no matter what vibrations are applied by the vibrator 3, the second jig 20 itself will not resonate.

[0084] Also, generally, the natural frequency is lower as the mass of the object is larger and higher as the rigidity is larger. Therefore, for example, by shortening the length dimension of the second jig 20, selecting a light material (e.g., resin) as the material of the second jig 20, or making the overall shape of the second jig 20 (excluding the shapes of the contact portions 21a, 23a, 25a, and 27a) a shape that is difficult to deform, the natural frequency can be increased. Conversely, for example, by increasing the length dimension of the second jig 20, selecting a heavy material (e.g., aluminum) as the material of the second jig 20, or making the overall shape of the second jig 20 (excluding the shapes of the contact portions 21a, 23a, 25a, and 27a) a shape that is easy to deform, the natural frequency can be decreased. By these means, it becomes possible to easily shift the natural frequency of the second jig 20 outside the specified frequency range.

[0085] In addition to simply changing (setting) the length dimension, material, or overall shape of the second jig 20, various combinations of changes such as changing (setting) the length dimension and material of the second jig 20, the material and overall shape of the second jig 20, the length dimension and overall shape of the second jig 20, and the length dimension, material, and overall shape of the second jig 20 can be made so as to shift the natural frequency of the second jig 20 outside the specified frequency range.

[0086] Also, "changing the overall shape" includes changing a solid one to a hollow one or a hollow one to a solid one without changing the outer shape. Therefore, even without changing the length dimension or material, for example, by making the solid second jig 20 hollow, weight reduction can be achieved, and thereby, it is also possible to increase the natural frequency.

[0087] As an example, when using a second jig 20" with a length dimension shorter than that of the second jig 20', specifically, a second jig 20" with a length dimension of 50 mm, since the second jig 20" is less likely to deform (has high rigidity), as shown in Fig. 8(b), the resonance frequency of the second jig 20" can be raised to 787 Hz. As a result, it becomes possible to evaluate the dynamic characteristics of the weatherstrip 50 even for the stuffy sound and mid-frequency road noise, which were difficult when using the second jig 20'.

[0088] Here, if the second jig 20" whose "specified frequency range" can be expanded up to 787 Hz is used, it becomes possible to measure the dynamic characteristics of the weather strip 50 not only for the stuffy sound and mid-frequency load noise but also for the drumming noise. However, when the second jig 20" with a shorter length dimension than the second jig 20' is used, since the test specimen 40 naturally becomes shorter, the stress applied to the test specimen 40 becomes smaller than when the second jig 20' is used. Also, in the actual vehicle 60, where the long weather strip 50 is installed, the shorter the test specimen 40 becomes, the farther it is from the state of being installed on the vehicle 60. On the other hand, when the second jig 20 becomes longer, even when resonance does not occur, it is assumed that the second jig 20 sways (the amplitudes are different at both ends in the longitudinal direction of the second jig 20). Therefore, it is preferable to perform the dynamic characteristic test by selectively using a plurality of second jigs 20 with different natural frequencies according to the type of low-frequency noise and low-frequency vibration to be evaluated (according to the "specified frequency range").

[0089] As described above, according to the dynamic characteristic test system 1 according to the present embodiment, in order to simulate the state of being mounted on the vehicle 60, at least one of the dimensions, material, and overall shape of the second jig 20 is set so that the natural frequency of the second jig 20 is out of the "specified frequency range" while maintaining the cross-sectional shapes of the contact portions 21a, 23a, 25a, 27a. Therefore, it is possible to suppress the second jig 20 from resonating in the "specified frequency range", and thereby accurately evaluate the dynamic characteristics of the weather strip 50.

[0090] Moreover, according to the "specified frequency range", even if changes are made to the dimensions, etc. of the second jig 20 (even if a plurality of second jigs 20 with different dimensions, etc. are selectively used), while maintaining the cross-sectional shapes of the contact portions 21a, 23a, 25a, 27a, due to the particularity of the weather strip 50 that the cross-sectional shape to be extrusion-molded is constant, by adjusting the cutting length of the weather strip 50 as the test specimen 40 according to the dimensions, etc. of the second jig 20, it is possible to easily perform tests corresponding to various frequency ranges.

[0091] -Dynamic characteristic test method- In the method for testing the dynamic characteristics of the weatherstrip 50, the above dynamic characteristic test system 1 is prepared. At this time, while maintaining the cross-sectional shapes of the contact portions 21a, 23a, 25a, and 27a, a second jig 20 in which at least one of the length dimension, material, and overall shape is set is used so that the natural frequency thereof is outside the specified frequency range.

[0092] Next, according to the second jig 20 to be used, after attaching the test piece 40 obtained by cutting the long weatherstrip 50 to the first jig 10, vibration is applied to the second jig 20 and the test piece 40 while changing the frequency and amplitude by the vibrator 3 via the impedance head 9 and the second jig 20. Then, the dynamic characteristics of the weatherstrip 50 are calculated based on the detected values detected by the impedance head 9 using the generator / analyzer 7 and the PC 30.

[0093] -Test Results- An example of the dynamic characteristics of the weatherstrip 50 obtained by performing the above dynamic characteristic test is shown below. The dynamic characteristic test is preferably carried out in a test chamber set at a constant temperature, and the floor surface has a strength sufficient to withstand the weight of the vibration test system and the mounted object and the generated vibration force, and sufficiently suppresses the occurrence of vibration propagation transmitted to the floor during the test. In this case, for the weatherstrip 50 mainly composed of EPDM, the above dynamic characteristic test system 1 was used in a semi-anechoic chamber set at the standard temperature (23°C). Further, the dynamic characteristic test was performed for both the outer peripheral side weatherstrip 51 attached to the outer peripheral edge of the door 63 and the inner peripheral side weatherstrip 53 attached along the door opening of the body 61 with respect to two locations, the roof portion Rf and the hinge portion Hg.

[0094] At that time, the state when the door is closed in the design, that is, the second jig 20 was set at the normal position so that the interval between the first jig 10 and the second jig 20 becomes the normal interval when the door is closed in the design. That is, from the state where the second jig 20 is in contact with the specimen 40, it is further pushed in, and with the displacement at the normal position in this pushed-in state set to 0 mm, while increasing the frequency at a speed of 1 Hz / s, the force required to vibrate the second jig 20 and the acceleration at that time were detected by the impedance head 9.

[0095] FIGS. 9, 10, and 11 are graphs showing the storage modulus E', loss modulus E", and loss factor η of the weatherstrip (corresponding to FIGS. 3(a) and 4(a)) attached to the door 63 side, respectively, and FIGS. 12, 13, and 14 are graphs showing the storage modulus E', loss modulus E", and loss factor η of the weatherstrip (corresponding to FIGS. 3(b) and 4(b)) attached to the body 61 side, respectively. In FIGS. 9 to 14, "Roof" (thick solid line) corresponds to the roof portion Rf, and "Hinge" (thick dashed line) corresponds to the hinge portion Hg.

[0096] According to the dynamic characteristic test system 1 to the dynamic characteristic test method according to the present embodiment, as shown in FIGS. 9 to 14, without resonating the second jig 20, the storage modulus E' representing the elasticity of the weatherstrip 50, the loss modulus E" representing the viscosity of the weatherstrip 50, and the loss factor η representing the degree of contribution of the viscosity in the weatherstrip 50 can be obtained, and thereby, the dynamic characteristics of the weatherstrip 50 can be obtained (evaluated) simply and accurately.

[0097] Note that the storage modulus E', loss modulus E", and loss factor η obtained in this way may be used to evaluate the dynamic characteristics of the weatherstrip 50 by themselves, or may be used, for example, for setting initial conditions in dynamic characteristic analysis by CAE (Computer Aided Engineering).

[0098] Thus, the merits of accurately obtaining the dynamic characteristics of the weather strip 50 are as follows. That is, as representative sounds of NV (Noise Vibration) phenomena occurring at 800 Hz or less in a vehicle, as described above, drumming noise (~50 Hz or less), stuffy sound (50 - 400 Hz), and mid-frequency road noise (200 - 500 Hz) can be cited. Since these are airborne sounds, the sound is radiated by vibrations on the door panel surface or the like. Therefore, if the dynamic characteristics of the weather strip 50 can be accurately obtained, the occurrence of drumming noise, stuffy sound, and mid-frequency road noise can be predicted, and by tuning the dynamic characteristics of the weather strip 50, it is possible to make it difficult to generate airborne sound.

[0099] (Other Embodiments) The present invention is not limited to the embodiments, and can be implemented in various other forms without departing from its spirit or main features.

[0100] In the above embodiment, the first jig 10, the second jig 20, the impedance head 9, and the vibrator 3 are arranged from bottom to top in this order, but it is not limited to this. For example, they may be arranged horizontally, or for example, if mask cancellation processing is to be performed, the first jig 10, the second jig 20, the impedance head 9, and the vibrator 3 may be arranged from top to bottom in this order.

[0101] Also, in the above embodiment, the generator / analyzer 7 and the PC 30 are configured to calculate the storage modulus E', the loss modulus E", and the loss factor η as dynamic characteristics, but it is not limited to this. The generator / analyzer 7 and the PC 30 may be configured to calculate other items.

[0102] Thus, the above-described embodiments are merely examples in all respects and should not be construed in a limiting sense. Further, modifications and changes belonging to the equivalent scope of the claims are all within the scope of the present invention.

Industrial Applicability

[0103] According to the present invention, since the dynamic characteristics of the weatherstrip can be easily and accurately evaluated, it is extremely beneficial to apply it to a test system and a dynamic characteristic test method for evaluating the dynamic characteristics of the weatherstrip.

Description of Reference Numerals

[0104] 1 Dynamic characteristic test system 3 Vibration generator 7 Generator / analyzer (dynamic characteristic calculation means) 9 Impedance head 10 First jig 11a, 13a, 15a, 17a Mounting part 20 Second jig 21a, 23a, 25a, 27a Contact part 30 Personal computer (dynamic characteristic calculation means) 40, 41, 43, 45, 47 Specimen 50 Weatherstrip 60 Vehicle 61 Body (door opening) 61a, 63a Weatherstrip mounting part 61b, 63b Weatherstrip contact part 63 Door

Claims

1. A dynamic characteristic test system for a weatherstrip that simulates a state of being mounted on a vehicle, applies vibration to a specimen obtained by cutting the weatherstrip in a direction perpendicular to its longitudinal axis, and evaluates its dynamic characteristics, comprising: a first jig having a mounting portion that simulates a cross-sectional shape of a weatherstrip mounting portion in either one of a door and a door opening, and to which the specimen is mounted; a second jig having a contact portion that simulates a cross-sectional shape of a weatherstrip contact portion in the other one of the door and the door opening, and being arranged opposite to the first jig so as to sandwich the specimen between the contact portion and the mounting portion; an impedance head that detects a force required to vibrate the second jig and an acceleration at that time; a vibrator capable of applying vibration in a specified frequency range to the second jig in a direction opposite to the first jig via the impedance head; dynamic characteristic calculation means for calculating the dynamic characteristics of the weatherstrip based on a detection value detected by the impedance head; and the second jig is characterized in that at least one of a dimension, a material, and an overall shape in a direction orthogonal to a cross-section of the contact portion is set while maintaining the cross-sectional shape of the contact portion so that its natural frequency is outside the specified frequency range. A dynamic characteristic test system for a weatherstrip.

2. In the dynamic characteristic test system for a weatherstrip according to Claim 1 above, the first jig, the second jig, the impedance head, and the vibrator are arranged in this order from bottom to top. A dynamic characteristic test system for a weatherstrip.

3. A dynamic characteristic test method for a weatherstrip that simulates a state of being mounted on a vehicle, applies vibration to a specimen obtained by cutting the weatherstrip in a direction perpendicular to its longitudinal axis, and evaluates its dynamic characteristics, comprising: a first jig having a mounting portion that simulates a cross-sectional shape of a weatherstrip mounting portion in either one of a door and a door opening, and to which the specimen is mounted; a second jig having a contact portion that simulates a cross-sectional shape of a weatherstrip contact portion in the other one of the door and the door opening, and being arranged opposite to the first jig so as to sandwich the specimen between the contact portion and the mounting portion; an impedance head that detects a force required to vibrate the second jig and an acceleration at that time; Via the impedance head, a vibrator capable of applying vibrations in a specified frequency range to the second jig in the direction facing the first jig is prepared. As the second jig, one is used in which at least one of the dimension, material, and overall shape in the direction orthogonal to the cross-section of the contact portion is set while maintaining the cross-sectional shape of the contact portion so that its natural frequency is outside the specified frequency range. A method for testing the dynamic characteristics of a weatherstrip, characterized by calculating the dynamic characteristics of the weatherstrip based on the detection value detected by the impedance head.

4. In the method for testing the dynamic characteristics of a weatherstrip according to claim 3 above, A method for testing the dynamic characteristics of a weatherstrip, characterized by using the first jig, the second jig, the impedance head, and the vibrator arranged in this order from bottom to top.

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