JPH0534086U - Car muffler noise reduction device - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a device that has fewer constituent parts and can effectively reduce muffled noise. [Structure] A mass member 10 having a predetermined vibration characteristic for the trunk lid 2 is arranged on the trunk lid 2 or a spare tire pan 3 facing the trunk member 2, and the mass member 10 makes the trunk lid 2 a spar tire pan 3. On the other hand, it was set to vibrate in phase.

Description

[Detailed description of the device]

[0001]

[Industrial application]

 The present invention relates to a device for reducing muffled noise generated in the interior space of an automobile.

[0002]

[Prior Art]

 Generally, when a vehicle is traveling, a muffled sound is generated due to the vibration of each panel forming the vehicle interior space.

In order to suppress this muffled sound, there is a method in which a vibration damping member is arranged on those panels or a vibration sensor and an actuator are set for each panel.

In the latter, the vibration sensor detects the vibration state of the panel, and based on this signal, the actuator suppresses the vibration of the panel.

[0005]

[Problems to be solved by the device]

 However, in such a conventional device, since the vibration of the panel is simply suppressed, the muffled sound cannot be effectively suppressed. Further, since the vibration is suppressed for each panel, it is necessary to dispose the vibration suppression member and the control device on all of the panels, resulting in an increase in vehicle weight and an increase in cost.

Therefore, an object of the present invention is to provide an apparatus which has less components than the conventional one and can effectively reduce muffled noise.

[0007]

[Means for Solving the Problems]

 This invention has been made in view of such a conventional problem. An interior space of an automobile is formed by a plurality of panels. The present invention is characterized in that the vehicle muffler noise reducing device is provided with a control means having a vibration characteristic, and the control means is set to vibrate the one panel in phase with the other panel.

[0008]

[Work]

 According to such means, when a panel surrounding the vehicle compartment vibrates due to traveling of an automobile or the like, one panel vibrates in phase with the other panel by the control means.

If the panels that are substantially opposite to each other vibrate in the same phase in this manner, the pressure fluctuations of the air in the vehicle compartment space will always be in the +-opposite phase on both panel sides, and they will cancel each other out to increase the sound pressure level in the vehicle compartment space. Can be held low.

[0010] Therefore, in this case, since one panel that is substantially opposed to the other panel is vibrated in the same phase as the other panel to reduce the muffled sound, the panel vibration is compared with the one that simply suppresses the panel vibration. Then, the muffled sound can be effectively reduced. Further, since it is only necessary to provide the control means for only one of the pair of panels facing each other, it is possible to reduce the number of parts as compared with the conventional arrangement in which an actuator or the like is provided for each panel. be able to.

[0011]

【Example】

 The invention will be described below with reference to the drawings.

1 to 16 are views showing a first embodiment of the present invention.

First, the configuration will be described. In FIG. 1, reference numeral 1 is a trunk room which is a vehicle compartment space of an automobile. The trunk room 1 includes a trunk lid 2, a spare tire pan 3, a rear panel 4 and a rear seat back panel 5. It is defined by etc.

The trunk lid 2 and the spare tire pan 3 substantially face each other, and the trunk lid 2 is mainly composed of an outer panel 6 and an inner panel 7, as shown in FIGS. 2 and 3. There is. The inner panel 7 has openings formed at a plurality of locations for the purpose of reducing weight, and has a substantially quadrangular ring-shaped frame portion 7a and a cross-shaped hat-shaped cross-section portion 7b formed inside the frame portion 7a. It consists of and.

The peripheral portion of the frame portion 7a of the inner panel 7 and the peripheral portion 6a of the outer panel 6 are connected by hemming, and the flange portion 7c of the cross-shaped hat-shaped cross-section portion 7b of the inner panel 7 is formed. It is fixed to the outer panel 6 by a mastic sealer 11.

Further, a mass member 10 having a predetermined weight as a control means is attached to both flanges 7c of the crosspiece 7b at the center of the trunk lid 2 via a weld bolt 8 and a nut 9.

The weight of the mass member 10 is set so that the characteristic value of the trunk lid 2 is the same as the characteristic value of the spare tire pan 3.

Regarding the size of the mass member 10 in this case, since the weight of the track lid 2 and the spare tire pan 3 itself is about 10 kg, if the eigenvalue is set to 25 Hz, the vanes are as shown in the following formula 1. The outline is shown in.

[0019]

[Equation 1]

As a result, the spring constant k becomes k = 250,000 N / m.

Therefore, since the eigenvalue change of about 1 Hz is obtained by adding 1 kg of the mass member 10, the size of the mass member 10 may be determined using this as a guide.

Next, the operation of the muffled sound reducing apparatus configured as described above will be described.

A muffled sound is generated when the vehicle travels, but by disposing the mass member 10 on the trunk lid 2, the bounce resonance can be separated from other vehicle body resonances into a low frequency range, thereby reducing the ear sound pressure. .. When a 3 kg mass member 10 is added to the center of the trunk lid 2, as shown in the graph of FIG. 4, a characteristic curve (dashed line in the figure) obtained by doubling the spring of the weather lid and lock of the trunk lid 2 is shown. 2) and a characteristic curve in which the frequency of the bounce resonance is lowered by adding the mass member 10 (shown by the solid line in the figure), the sound pressure at the front seat ear can be reduced by about 6 dB at around 28 Hz. In this case, the trunk lid bounce resonance goes from 27.3 Hz to 22.6 Hz.

It is also apparent from the graphs shown in FIGS. 5 to 7 that the sound pressure at the ear can be reduced by adding the mass member 10.

That is, FIG. 5 shows a state in which the mass member 10 is not provided, the horizontal axis represents frequency (Hz) and the vertical axis represents acceleration (mm / s ² · kgf), and the response at the excitation point is shown. 2 shows the characteristic curve of and the characteristic curve of the response in the central portion of the trunk lid 2. In such a graph, there is no significant difference between both characteristic curves.

Next, when the mass member 10 is provided, as shown in FIG. 6, the characteristic curve showing the response at the excitation point and the characteristic curve showing the response at the central portion of the trunk lid 2 are compared. In the latter characteristic curve, it can be seen that the peak level decreases especially around 24 Hz.

Therefore, as shown in FIG. 7, when comparing the characteristic curve when the mass member 10 is added to the central portion of the trunk lid 2 with the current characteristic curve where the mass member 10 is not added, the mass member 10 It can be seen that the sound pressure level is lowered when is added. When the mass member 10 is added to the rear end of the trunk lid 2, the sound pressure level is not lower than that of the current one as shown in the characteristic curve.

Next, as shown in FIG. 8, the vehicle noise is considered with a mass spring model including the spare tire pan 3, the trunk lid 2 and the vehicle body S in the bending two-bar mode. m2 is the mass of the spare tire pan 3, m3 is the mass of the trunk lid 2, m1 is the mass of the vehicle body S (bending two-bar mode), k1, k2, k3 are the bending two-bar mode of the vehicle body S, and the spare tire pan 3 respectively. , The spring constant of the trunk lid 2.

Such a mass spring model exhibits vibration characteristics as shown in FIGS. 9 and 10. FIG. 9 shows the excitation point response of the vehicle body S at the bending 2-node, and FIG. 10 shows the response of the bending 2-node excitation trunk lid and spare tire. The horizontal axis represents frequency (Hz) and the vertical axis represents acceleration (mm / s ² · kgf). The arrows in each figure indicate the phase direction. Referring to FIG. 10, the level difference is large in the in-phase portion, and the phase is opposite in the small level difference portion. These are the conditions for high sound pressure.

Next, when the trunk lid 2 and the spare tire pan 3 have the same eigenvalue, vibration characteristics as shown in FIGS. 11 and 12 are shown. FIG. 11 shows the case of the excitation point response of the vehicle body S.sub.2 having two bends, and FIG. 12 shows the case of the trunk lid and spare tire response having two bends. Referring to FIG. 12, the spare tire pan 3 and the trunk lid 2 vibrate in the same phase, and the level difference between the peaks is small, so that the low sound pressure condition is satisfied. Therefore, muffled noise is reduced.

In other words, in the mass spring model shown in FIG. 8, when the trunk lid 2 and the spare tire pan 3 have the same individual eigenvalue, the trunk lid 2 and the spare tire pan 3 are affected by the vibration of the bend 2 of the vehicle body S. Indicates vibrations in the same phase or opposite phases (depending on the frequency), and the trunk lid 2 and the spare tire pan 3 always vibrate in the same phase.

If the spare tire pan 3 side and the trunk lid 2 side that are substantially opposed to each other vibrate in the same phase as described above, the pressure fluctuation of the air in the trunk room 1 is always +-on the spare tire pan 3 side and the trunk lid 2 side. The phases are opposite to each other, so that they cancel each other out, the volume change in the trunk 1 is minimized, the sound pressure level is suppressed low, and the muffled sound is reduced.

However, in the bending point response of the vehicle body S in the bending two-node mode shown in FIG. 11, there is a high peak of the vehicle body S of the two-node bending at 29 Hz.

Therefore, when the trunk lid 2 and the spare tire pan 3 are further set to be about 1 Hz below the vehicle body S having two bends, vibration characteristics as shown in FIGS. 13 and 14 are exhibited. FIG. 13 shows the vibration characteristics of the excitation point response of the vehicle body S at the two-bend bending, and FIG. 14 shows the vibration characteristics of the trunk lid and the spare tire response at the two-bending bending trunk lid. In this way, when set to around 1 Hz, the trunk lid 2 and the spare tire pan 3 act as a dynamic damper with two bends, and as shown in FIG. 13, the two peaks of the vehicle body S with two bends have substantially the same low level. Becomes The characteristic curve of the flexural 2-node vibration truncation and spare tire pan response shown in FIG. 14 is substantially the same as the characteristic curve shown in FIG.

As shown in FIGS. 15 and 16, these are graphs of the vehicle body radiation coefficient at the optimization point. FIG. 15 shows the case where the trunk lid 2 and the spare tire pan 3 are set to the same eigenvalue. , The solid line shows the conventional characteristic curve, and the broken line shows the characteristic curve set to the same eigenvalue. As is clear from FIG. 15, the peak at 30 Hz is not improved, but as a whole, an improvement is seen in the shaded area. Further, in FIG. 16, the trunk lid 2 and the spare tire pan 3 are set to have the same eigenvalue, and further, the trunk lid 2 and the spare tire pan 3 are set to 1 Hz before, below, and below the eigenvalue of the vehicle body S in the bend 2 section. In this case, the solid line shows the conventional characteristic curve, and the broken line shows the characteristic curve set to the same eigenvalue. As is apparent from FIG. 16, all frequencies below 30 Hz are improved.

In this way, since the trunk lid 2 is vibrated to reduce the muffled noise in response to the vibration of the spare tire pan 3 which is substantially opposed to the spare tire pan 3, the panel vibration is simply suppressed as in the conventional case. The muffled sound can be effectively reduced as compared with the one that does. Further, since it is only necessary to provide the mass member 10 on the trunk lid 2, the number of parts is reduced as compared with the conventional one in which an actuator or the like is provided for each panel.

17 and 18 are views showing a second embodiment of the present invention.

This embodiment is different from the first embodiment in that the mass member 12 as the control means is attached to the spare tire pan 3 side.

When the eigenvalue of the spare tire pan 3 is higher than the eigenvalue of the trunk lid 2, the mass member 12 is attached to the spare tire pan 3 as in this embodiment. That is, a substantially cylindrical fixing bracket 13 is attached to the spare tire pan 3, and a donut-shaped mass member 12 is fitted around the fixing bracket 13 and fixed by bonding the bottom surface portion. There is.

A spare tire wheel 16 is attached to the upper surface of the fixing bracket 13 with a nut 14 and a weld bolt 15.

By disposing the mass member 12, the eigenvalue of the spare tire pan 3 is set to be the same as the eigenvalue of the trunk 2.

Even in this case, the same effect as that of the first embodiment can be obtained.

19 and 20 show a third embodiment of the present invention.

In this embodiment, a control member 18 as control means is arranged on the back side of the trunk lid 2. Specifically, the control member 18 is composed of a reinforcing beam member 19 and three elastic members 20. The reinforcing beam member 19 is rod-shaped and has sufficient bending rigidity, and is laid across the entire vehicle width direction by fastening both ends 19a to the frame portion 7a of the inner panel 7 with screws 21. .. The elastic member 20 is made of a rubber material and is set to have a predetermined spring constant, and is interposed between the cross section 7 b of the inner panel 7 and the reinforcing beam member 19.

By adjusting the spring constant of the elastic member 20, the surface rigidity of the trunk lid 2 can be easily controlled, so that the membrane resonance mode of the trunk lid 2 can be controlled and the trunk lid 2 can be controlled. The eigenvalue of 2 is set to be in phase with the eigenvalue of the spare tire pan 3.

The elastic member 20 exhibits spring characteristics as shown in the graph of FIG. In this graph, the vertical axis is the reaction force F of the elastic member 20 and the horizontal axis is the length S of the elastic member 20, and the slope of the characteristic curve represents the spring constant k. The length S of the elastic member 20 is set so that the spring constant k becomes a predetermined value.

By doing so, it is possible to reduce the noise in the vehicle compartment, as in the above-described embodiments.

Moreover, even after completion of the product, the surface rigidity of the trunk lid 2 can be easily controlled by replacing the elastic member 20, and even if product variation occurs, the membrane resonance of the trunk lid 2 is off-line. It becomes possible to optimally control the frequency and mode.

21 to 24 show a fourth embodiment of the present invention.

The control member 22 as the control means of this embodiment includes a spring portion 23 having a length that extends substantially over the entire width in the vehicle width direction, and two pairs of hooking pieces 24 projecting upward from the spring portion 23. Are molded as a single body.

The control member 22 is attached to the inner panel 7 of the trunk lid 2. That is, the spring portion 23 is installed on the frame portion 7a of the inner panel 7 along the vehicle width direction. In detail, the spring portion 23 is curved as shown by the chain double-dashed line in FIG. 22 when no external force is applied, and the left end portion 23a on the left side in FIG. A right end portion 23b on the right side of the center 22 is fixed with a screw 26 so as to be positionally adjustable in the vehicle width direction. That is, a long hole 23c extending in the vehicle width direction is formed in the right end portion 23b, and the screw 26 is inserted into the long hole 23c to be attached to the inner panel 7. Further, the latching piece 24 is formed with a locking portion 24a whose upper end is bent inward, and this locking portion 24a is hooked on the crosspiece 7b of the inner panel 7 (FIG. 23 and See FIG. 24).

In the thus hooked state, the spring portion 23 is deformed from the state shown by the chain double-dashed line in FIG. 22 to the state shown by the solid line, so that the force F is directed downward in FIG. As a result, the surface rigidity of the trunk lid 2 is improved.

Then, by adjusting the mounting position of the right end portion 23b of the spring portion 23, the force F can be adjusted and the surface rigidity of the trunk lid 2 can be set to a predetermined value.

In this way, the surface rigidity of the trunk lid 2 can be easily controlled, and the vehicle interior noise is reduced by making the eigenvalue of the trunk lid 2 the same as the eigenvalue of the spare tire pan 3 as in the above embodiment. be able to.

Moreover, even after the completion of the product, the surface rigidity of the trunk lid 2 can be easily controlled by adjusting the mounting position, so that the trunk lid 2 can be off-line even when product variations occur. It is possible to optimally control the membrane resonance frequency and the mode.

[0056]

[Effect of the device]

 As described above, according to the present invention, the interior space of the automobile is formed by a plurality of panels, and one of the panels that substantially opposes the other panel has a predetermined vibration characteristic. By providing a control means for controlling the one panel to vibrate in phase with the other panel by the control means, it is effective as compared with the conventional one that simply suppresses the vibration of the panel. The muffled sound can be reduced. However, the number of control elements (sensors, actuators, control devices, etc.) is half that in the case where vibration is suppressed for each panel, which is a useful effect in practice.

[Brief description of drawings]

FIG. 1 is a schematic view of a trunk room showing a first embodiment of a muffled noise reducing apparatus for an automobile according to the present invention.

FIG. 2 is a perspective view of the trunk lid of the first embodiment.

FIG. 3 is a sectional view taken along line AA of FIG. 2 of the first embodiment.

FIG. 4 is a graph showing a relationship between a vehicle body frequency of a front seat ear sound pressure and a radiation coefficient.

FIG. 5 is a graph showing a relationship between frequency and acceleration when a mass member is not added.

FIG. 6 is a graph showing the relationship between frequency and acceleration when a mass member is added to the center of the trunk lid.

FIG. 7 is a graph showing the relationship between frequency and sound pressure.

FIG. 8 is a diagram showing a mass spring model.

FIG. 9 is a graph showing a bending 2-node excitation point response.

FIG. 10 is a graph showing a response of a bending two-node vibrating trunk lid and a spare tire pan.

FIG. 11 is a graph showing a bending two-node vibration response when the trunk lid and the spare tire pan have the same eigenvalue.

FIG. 12 is a graph showing a response of a bending two-node vibration trunk lid and a spare tire when the trunk lid and the spare tire pan have the same eigenvalue.

FIG. 13 is a graph showing a bending 2-node excitation point response when the trunk lid and the spare tire pan have the same eigenvalue, and the trunk lid and the spare tire pan are set to around 1 Hz below the bending 2-node. .

FIG. 14 shows the same response values for the trunk lid and the spare tire pan, and when the trunk lid and the spare tire pan are set to around 1 Hz below the bend 2 joint, the flexural 2-bar vibration trunk lid and spare tire pan response are shown. It is a graph figure which shows.

FIG. 15 is a graph showing a vehicle body radiation coefficient when the trunk lid and the spare tire pan have the same eigenvalue.

FIG. 16 is a graph showing the vehicle body radiation coefficient when the trunk lid and the spare tire pan have the same eigenvalue, and the trunk lid and the spare tire pan are set to around 1 Hz below the bending point 2;

FIG. 17 is a perspective view of the inside of a luggage compartment showing a second embodiment of the present invention.

FIG. 18 is a sectional view taken along the line BB of FIG. 17 showing the second embodiment.

FIG. 19 is a sectional view taken along the vehicle width direction of the trunk lid according to the third embodiment.

FIG. 20 is a graph showing spring characteristics of the elastic member according to the third embodiment.

FIG. 21 is a perspective view of a trunk lid showing a fourth embodiment of the present invention.

FIG. 22 is a sectional view taken along the line CC of FIG. 21 showing the fourth embodiment.

FIG. 23 is a sectional view taken along the line DD of FIG. 21 showing the fourth embodiment.

FIG. 24 is a perspective view showing a part of an inner panel and a control member according to the fourth embodiment.

[Explanation of symbols]

 1 Trunk room (vehicle space) 2 Trunk lid (one panel) 3 Spare tire pan (other panel) 10 Mass member (control means) 12 Mass member (control means) 18,22 Control member

Claims (4)

[Scope of utility model registration request] 1. A vehicle interior space is formed by a plurality of panels, and a control means for causing one of the panels to have a predetermined vibration characteristic is provided on one of the panels substantially facing each other. Thus, the muffled noise reducing apparatus for an automobile, wherein the one panel is set to vibrate in phase with the other panel. 2. The one panel is a trunk lid, and the control means includes a reinforcing beam member erected on the back surface side of the trunk lid with both ends fixed, and the reinforcing beam member and The muffled noise reducing apparatus for an automobile according to claim 1, further comprising an elastic member interposed between the back surfaces of the trunk lid. 3. The one panel is a trunk lid composed of an outer panel and an inner panel, and the control means includes a spring piece erected on the back side of the trunk lid with both ends fixed, and the spring. A locking piece extending upward from the one piece and locked to the inner panel, and with the spring piece deformed upward, the locking piece is locked to the inner panel to lower the trunk lid downward. The muffled sound reducing device for an automobile according to claim 1, wherein the device is arranged so as to be retracted. 4. The one panel is a trunk lid or a spare tire pan, and the control means is a mass member attached to the trunk lid or the spare tire pan. Muffler noise reduction device for automobiles.