Method of and apparatus for predicting vehicle interior noise

• US 6,529,838 B1
• Filed: 06/16/1998
• Issued: 03/04/2003
• Est. Priority Date: 06/16/1997
• Status: Expired due to Fees

• Current Assignee: Bridgestone Corporation, Honda Motor Co., Ltd. (Honda Motor Company)
• Original Assignee: Bridgestone Corporation, Honda Motor Co., Ltd. (Honda Motor Company)
• Inventors: Kudo, Ken, Yamashita, Tsuyoshi, Yoshimura, Yuichi, Suto, Akira, Horiuchi, Mamoru
• Primary Examiner(s): WACHSMAN, HAL D
• Application Number:
  US09/097,588
• Time in Patent Office: 1,722 Days
• Field of Search: 702/41, 702/33, 702/39, 702/42, 702/43, 702/56, 702/75-77, 702/103, 702/105, 702/106, 702/108, 702/109, 702/111, 702/113-115, 702/124, 702/126, 702/138, 702/140, 702/182, 702/183, 702/188, 702/189, 702/191, 702/193-195, 702/FOR.123, 702/FOR.124, 702/FOR.126, 702/FOR.134, 702/FOR.135, 702/FOR.143, 702/FOR.166, 702/FOR.168, 702/FOR.170, 702/FOR.171, 731/46, 73/8, 735/70, 735/79, 735/81, 735/87, 736/02, 736/45--48, 381/71.12, 381/56, 381/71.1, 381/71.4, 381/86, 700/280, 703/7, 703/8
• US Class Current: 702/41
• CPC Class Codes: G01H 17/00 Measuring mechanical vibrations or ultrasonic, sonic or infrasonic waves, not provided for in the preceding groups see provisionally also G01H1/00
• CPC Class Codes: G01H 3/08 Analysing frequencies present in complex vibrations, e.g. comparing harmonics present acoustic presence detection G01V1/001

Abstract

A jig is successively mounted on each of the four wheels of a vehicle. The jig is struck in three orthogonal directions independently, and at the same time, a microphone inside the vehicle measures the sound pressure of noise generated due to the exciting force. An FFT analyzer operates a frequency response function from the exciting force to the sound pressure. In a drum testing machine, a tire to be subject to noise prediction is mounted on a shaft, the tire is rotated, and the axial force in the three orthogonal directions is measured. The axial force signal is input to the FFT analyzer and the auto power spectrum in the three orthogonal directions and the cross power spectrum between two different axial directions are operated. The frequency response functions are synthesized with the auto power and cross power spectrums, and the power spectrum of the road noise is operated.

Claims

1. A method of predicting vehicle interior noise, comprising:

obtaining a frequency response function and a power spectrum in accordance with the following (a) and (b), wherein

(a) an exciting force is applied to at least one axle of a vehicle on which standard tires are mounted in predetermined directions, the applied exciting force and a sound pressure of noise generated inside the vehicle due to the applied exciting force are measured, the frequency response function in which the exciting force in said predetermined directions serves as an input and the sound pressure of the noise generated inside the vehicle serves as an output is obtained, and

(b) axial force whose directions are the same as said predetermined directions and which is generated at an axle when a tire which is to be subject to noise prediction is rotated in an axially fixed state on a drum testing machine having a surface simulating the unevenness of a road surface is measured, and the power spectrum relating to the measured axial force in said predetermined directions is obtained; and

on the basis of said frequency response function and said power spectrum, predicting vehicle interior noise which is generated when a vehicle runs on the road surface.

2. The method of predicting vehicle interior noise according to claim 1, wherein said frequency response function and said power spectrum relating to said axial force in said predetermined directions are multiplied for every predetermined direction and for every position at which a tire is mounted, and the obtained products are added together so as to predict the interior noise of a vehicle.

3. The method of predicting vehicle interior noise according to claim 1, wherein said predetermined directions are any one of the following:

three orthogonal axial directions comprising an axis in the longitudinal direction of the vehicle, an axis in the transverse direction of the vehicle, and an axis in the vertical direction of the vehicle;

six directions comprising the three orthogonal axial directions and directions encircling the three orthogonal axial directions and;

selected directions from among the three orthogonal axial directions and the directions encircling the three orthogonal axes.

4. A method of predicting vehicle interior noise, comprising:

obtaining a frequency response function, an auto power spectrum, and a cross power spectrum in accordance with the following (a) and (b), wherein

(a) an exciting force is applied to at least one axle of a vehicle on which standard tires are mounted in three orthogonal axial directions, for each of three orthogonal axes, the applied exciting force and a sound pressure of noise generated inside the vehicle due to the applied exciting force are measured, the frequency response function in which the exciting force in said three orthogonal axial directions serves as an input and the sound pressure of the noise generated inside the vehicle serves as an output is obtained for each of the three orthogonal axes, and

(b) axial force in said three orthogonal axial directions which is generated at an axle when a tire which is to be subject to noise prediction is rotated in an axially fixed state on a drum testing machine having a surface simulating the unevenness of a road surface is measured for each of the three orthogonal axes, and an auto power spectrum of the measured axial force in each of said three orthogonal axial directions and a cross power spectrum in the direction between two different axes of the three orthogonal axes are obtained; and

on the basis of said frequency response function, said power spectrum, and said cross power spectrum, predicting vehicle interior noise which is generated when the vehicle runs on the road surface.

5. The method of predicting vehicle interior noise according to claim 4, wherein said frequency response function is multiplied by said auto power spectrum and said frequency response function is multiplied by said cross power spectrum for every related predetermined direction and for every related position at which a tire is mounted, and the obtained products are added together so as to predict the interior noise of the vehicle.

6. An apparatus for predicting vehicle interior noise, comprising:

excitation means which applies exciting force in predetermined directions to at least one axle of a vehicle on which standard tires are mounted;

first measuring means which measures the applied exciting force and a sound pressure of noise generated inside a vehicle due to the exciting force;

function operating means which operates the frequency response function in which the exciting force in said predetermined directions serves as an input and the sound pressure of the noise generated inside the vehicle serves as an output;

a drum testing machine which has a surface simulating the unevenness of a road surface;

second measuring means for measuring an axial force whose directions are the same as said predetermined directions and which is generated at an axle when a tire which is to be subject to noise prediction is rotated on said drum testing machine in an axially fixed state;

spectrum operating means which operates the power spectrum relating to the measured axial force in said predetermined directions; and

predicting means which, on the basis of said frequency response function and said power spectrum, predicts the vehicle interior noise which is generated when the vehicle runs on the road surface.

7. The apparatus for predicting vehicle interior noise according to claim 6, wherein said excitation means comprises:

an exterior jig for striking an axle which includes an impact portion and a disk portion and which is mounted on the rim of a tire; and

an impulse hammer which includes a force sensor for detecting excitation force due to impact and which strikes the impact portion of said exterior jig for striking an axle.

8. The apparatus for predicting vehicle interior noise according to claim 6, wherein said frequency response function and said power spectrum relating to the measured axial force in said predetermined directions are multiplied for every predetermined direction and for every position at which a tire is mounted, and the obtained products are added together so as to predict the interior noise of a vehicle.

9. The apparatus for predicting vehicle interior noise according to claim 6, wherein said predetermined directions are any one of the following:

three orthogonal axial directions comprising an axis in the longitudinal direction of the vehicle, an axis in the transverse direction of the vehicle, and an axis in the vertical direction of the vehicle;

six directions comprising the three orthogonal axial directions and directions encircling the three orthogonal axial directions and;

selected directions from among the three orthogonal axial directions and the directions encircling the three orthogonal axes.

10. An apparatus for predicting vehicle interior noise, comprising:

excitation means which applies exciting force in three orthogonal directions to at least one axle of a vehicle, on which standard tires are mounted, for each of three orthogonal axes;

first measuring means which measures the applied exciting force and a sound pressure of noise generated inside a vehicle due to the applied exciting force for each of the three orthogonal axes;

function operating means which operates a frequency response function for each of the three orthogonal axes in which the applied exciting force in the three orthogonal directions serves as an input and the sound pressure of the noise generated inside the vehicle serves as an output;

a drum testing machine which has a surface simulating the unevenness of a road surface;

spectrum operating means for measuring, for each of the three orthogonal axes, the axial force in the three orthogonal axial directions which is generated at a shaft when a noise prediction subject tire is rotated on said drum testing machine in an axially fixed state, and for operating an auto power spectrum of the measured axial force in each of the three orthogonal axial directions and a cross power spectrum in the direction between two different axes of the three orthogonal axes; and

predicting means which, on the basis of said frequency response function, said auto power spectrum, and said cross power spectrum, predicts the vehicle interior noise which is generated when the vehicle runs on the road surface.

11. The apparatus for predicting vehicle interior noise according to claim 10, wherein said excitation means comprises:

an exterior jig for striking an axle which includes an impact portion and a disk portion and which is mounted on the rim of a tire; and

an impulse hammer which includes a force sensor detecting excitation force due to impact and which strikes the impact portion of said exterior jig for striking an axle.

12. The apparatus for predicting vehicle interior noise according to claim 10, wherein said frequency response function is multiplied by said auto power spectrum and said frequency response function is multiplied by said cross power spectrum for every related predetermined direction and for every related position at which a tire is mounted, and the obtained products are added together so as to predict the interior noise of the vehicle.