JPH07159423A - Vehicle body mounting structure of angular velocity sensor for vehicle - Google Patents

Abstract

PURPOSE:To achieve an accurate detection of an angular velocity by minimizing effect on an angular velocity sensor of the vibration of a body generated therein during the running in a vehicle body mounting structure of the angular velocity sensor for a vehicle used as an input sensor of an on-vehicle control system having the angular velocity as input information. CONSTITUTION:A mounting bracket 2 is so formed in shape as to have a cantilever beam structure with a sensor case 1a and the bracket 2. With an angular velocity sensor 1 fixed on a body 3 through the mounting bracket 2, a resonance frequency fBR which the mounting bracket 2 has, is set lower than a drive resonance frequency fS which a detecting section has.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to angular velocity (yaw rate).
The present invention relates to a vehicle body mounting structure of an angular velocity sensor for a vehicle, which is used as an input sensor of a four-wheel steering control system or the like that controls vehicle behavior by using as input information.

[0002]

2. Description of the Related Art Conventionally, as a vehicle body mounting structure of a vehicle angular velocity sensor, for example, a structure shown in FIG. 10 is known.

[0003]

However, in the conventional vehicle body mounting structure of the angular velocity sensor for vehicle, the angular velocity sensor with the mounting bracket for detecting the angular velocity generated in the vehicle is directly mounted on the vehicle body. Therefore, there is a problem in that the angular velocity sensor is directly affected by the vibration of the vehicle body that occurs during traveling, and the angular velocity cannot be detected accurately.

That is, the frequency characteristic of the vehicle body vibration during traveling shows the characteristic as shown in FIG. 4, and the generated acceleration becomes the largest in the frequency region around fB which is the resonance frequency thereof. On the other hand, in many cases, the resonance frequency fS of the angular velocity sensor (= tuning fork drive resonance frequency of the sensor detector) is as shown in FIG.
As shown in (3), it exists in a frequency range close to the vehicle body resonance frequency fB. Therefore, due to the beat between the tuning fork resonance and the vehicle body resonance, as shown in the frequency characteristics of the sensor output value in FIG. 3, the sensor output value fluctuates greatly in the region around the resonance frequency fS of the angular velocity sensor. The frequency component of this sensor output value fluctuation has an extremely low frequency component of DC (direct current) to several tens Hz. Normally, the sensor unit is provided with a low-pass filter, but since the filter characteristic is set so as not to cause a phase delay in control, it is not possible to eliminate such a sensor output value variation having a low frequency component. Further, it is difficult to set the vehicle body resonance frequency fB while avoiding the sensor resonance frequency fS. Therefore, as long as the angular velocity sensor is directly mounted on the vehicle body, the influence of the angular velocity sensor on the vehicle body vibration cannot be reduced.

On the other hand, in a four-wheel steering system or the like mounted on a vehicle, in order to reduce the effects of side wind disturbances and road surface disturbances,
The yaw rate feedback control that matches the actual yaw rate generated in the vehicle with the target yaw rate set by the vehicle speed and the steering angle is applied.However, in this control, the actual yaw rate is obtained from the yaw rate sensor, and this detection accuracy level remains the same. It is effective for feedback control accuracy. Therefore, when aiming for highly accurate yaw rate feedback control, high yaw rate detection accuracy is inevitably required.

The present invention has been made in view of the above problems, and an object thereof is to mount a vehicle angular velocity sensor on a vehicle body used as an input sensor of an in-vehicle control system using angular velocity as input information. The object is to accurately detect the angular velocity by suppressing the influence of the vehicle body vibration generated on the vehicle body during traveling on the angular velocity sensor.

[0007]

To achieve the above object, in the vehicle body angular velocity sensor mounting structure of the present invention, the vehicle angular velocity sensor mounting body is provided with an angular velocity sensor for detecting an angular velocity generated in the vehicle. In the structure, the shape of the mounting bracket for mounting the angular velocity sensor on the vehicle body is formed so as to have a beam structure in the sensor case and the mounting bracket in the vehicle body mounted state, and the angular velocity sensor is fixed to the vehicle body via the mounting bracket. The resonance frequency of the mounting bracket is set lower than the drive resonance frequency of the sensor detection unit.

For example, the mounting bracket may be fixed to one side surface of the angular velocity sensor, and the shape of the mounting bracket may be formed so that the sensor case and the mounting bracket have a cantilever structure when mounted on the vehicle body. Also,
The mounting bracket is fixed to one side surface of the angular velocity sensor, and the shape of the mounting bracket is in a vehicle body mounted state,
The sensor case and the mounting bracket may be formed to have a doubly supported beam structure.

[0009]

When the angular velocity sensor detects the angular velocity during traveling, the shape of the mounting bracket for mounting the angular velocity sensor on the vehicle body is such that the sensor case and the mounting bracket have a beam structure when the vehicle body is mounted. Since the angular velocity sensor is affected by vibration via the mounting bracket, the influence of vibration from the vehicle body on the angular velocity sensor can be suppressed.

In addition, since the bracket resonance frequency of the mounting bracket is set lower than the drive resonance frequency of the sensor detector, both resonance frequencies have a deviation, and the beat of the bracket resonance frequency and the drive resonance frequency is changed. Occurrence is suppressed.

Therefore, the direct influence of the vehicle body vibration on the angular velocity sensor is suppressed by the interposition of the mounting bracket, and the influence on the angular velocity sensor by the bracket resonance frequency of the mounting bracket which affects the vibration on behalf of the vehicle body is also the resonance. By eliminating it by setting the frequency, the frequency characteristics of the sensor output value from the sensor detection section can be obtained with small fluctuations in the drive resonance frequency range of the sensor detection section, and the angular velocity can be detected accurately. To be done.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

(First Embodiment) First, the structure will be described.

FIG. 1 is a side view showing a vehicle body mounting structure of a vehicle angular velocity sensor according to a first embodiment of the present invention, and FIG. 2 is a diagram showing an angular velocity sensor and a sensor unit in a controller.

In FIG. 1, 1 is an angular velocity sensor, 2 is a mounting bracket, 3 is a vehicle body, 4 is a connector, and 5 is a screw.

A mounting bracket 2 for mounting on the vehicle body 3 is fixed to one side surface of the sensor case 1a of the angular velocity sensor 1 with screws, welding or the like. Further, the angular velocity sensor 1 is connected with a connector 4 for electrically connecting with a controller (not shown).

The mounting bracket 2 is fixed to the vehicle body 3 by screws 5, and the mounting bracket 2 has a cantilever structure in which the sensor case 1a and the mounting bracket 2 are mounted in the vehicle body. In addition, the case fixing portion 2a and the mounting extension portion 2b extending from the case fixing portion 2a in only one direction are formed.

As shown in FIG. 1, with the angular velocity sensor 1 fixed to the vehicle body 3 via the mounting bracket 2, the resonance frequency fBR of the mounting bracket 2 is the drive resonance frequency of the detection unit 1c described later. It is set lower than fS.

In FIG. 2, reference numeral 1 is an angular velocity sensor, 1a is a sensor case, 1b is a detection section case, 1c is a detection section, 1
d is an anti-vibration rubber, 2 is a mounting bracket, 4 is a connector,
6 is a sensor unit in the controller.

The detection section 1c is housed in a detection section case 1b, and the detection section case 1b is supported by the sensor case 1a via a vibration-proof rubber 1d.

The detection unit 1c is a tuning fork driving piezoelectric element 1.
0 and the first piezoelectric element 11 for detecting angular velocity are orthogonally coupled to each other, and the piezoelectric element 1 for monitoring the tuning fork vibration.
2 and a second vibrating unit for orthogonally coupling the second piezoelectric element 13 for angular velocity detection, and a connecting block 14 for connecting both vibrating units at the ends of the tuning fork side piezoelectric elements 10 and 12.
And a support pin 15 that supports the connecting block 14 at one point with respect to the detection unit case 1b.

The sensor unit 6 includes a current amplifier 6a, a bandpass filter 6b, a rectifier 6c, and a smoothing circuit 6d as circuits for vibrating the tuning fork with a constant amplitude.
A charge amplifier 6f, a bandpass filter 6g, a synchronous detector 6h, an integrator 6i, and an amplifier 6 as circuits for outputting an angular velocity signal.
j is provided.

Next, the operation will be described.

[Angular Velocity Detecting Action] When a sinusoidal voltage signal is applied to the tuning fork driving piezoelectric element 10 of the sensor detecting section 1b, the tuning fork vibration is started, and a current is generated according to the amount of charge generated in the tuning fork vibration monitoring piezoelectric element 12. The output voltage value of the amplifier 6a, the bandpass filter 6b, the rectifier 6c, and the smoothing circuit 6d changes, and the amplification degree changes according to this voltage value.
The circuit 6e causes the tuning fork to vibrate with a constant amplitude.

The charges generated in the two angular velocity detecting piezoelectric elements 11 and 13 in proportion to the angular velocity are the charge amplifier 6
f, a bandpass filter 6g, a synchronous detector 6h for detecting in synchronism with the tuning fork vibration period, an integrator 6i for smoothing by a lowpass filter, and an amplifier 6j to output as an angular velocity signal.

[Vehicle vibration influence reducing action] When the angular velocity is detected, the tuning fork of the detecting portion 1c has, for example, 700 Hz to 900 Hz.
It vibrates at a resonance frequency fS in the Hz band. When this angular velocity sensor is vibrated with a constant gain, the sensor output value largely fluctuates in the vicinity of the resonance frequency fS, as shown in FIG. This is due to the beat between the tuning fork resonance vibration and the sensor case resonance vibration.

On the other hand, the frequency component of the sensor output waveform in the vicinity of the resonance frequency fS has an extremely low frequency component of the difference between the tuning fork resonance frequency and the sensor case resonance frequency, which is applicable to vehicle control. It is difficult to reduce the output fluctuation with an electric filter having a component. Also,
As shown in FIG. 4, the vehicle body often has a resonance frequency fB in the vicinity of the tuning fork resonance frequency fS. When the sensor is directly attached to the vehicle body, the vibration received from the vehicle body during traveling is not attenuated and the sensor is not attenuated. Is transmitted to the sensor, which causes a large offset in the sensor output.

Therefore, in order to reduce this offset amount, the mounting structure of the sensor is not directly mounted on the vehicle body but is mounted via a bracket, and the sensor mounting structure is as shown in FIG.
It suffices to set a mounting bracket having frequency characteristics as shown in. That is, the angular velocity sensor may be fixed to the vehicle body through a mounting bracket in which the bracket resonance frequency fBR is set to have a frequency characteristic sufficiently lower than the sensor resonance frequency fS and the vehicle body resonance frequency fB.

Therefore, in this embodiment, as shown in FIG. 1, the bracket frequency characteristic shown in FIG. 5 is obtained by the mounting bracket 2 having a cantilever structure in a vehicle mounted state. That is, the bracket resonance frequency fBR of the mounting bracket 2 is set to a frequency characteristic sufficiently lower than the sensor resonance frequency fS and the vehicle body resonance frequency fB,
In addition, the gain G near the sensor resonance frequency fS and the vehicle body resonance frequency fB is set to G <0 [dB].

Thus, the vehicle body vibration near the sensor resonance frequency fS can be absorbed by the mounting bracket 2, and the fluctuation of the sensor output value can be suppressed to a small level as shown in FIG.

Next, the effect will be described.

(1) In a vehicle body mounting structure of a vehicle angular velocity sensor used as an input sensor of an in-vehicle control system that uses angular velocity as input information, the angular velocity sensor 1 is mounted on a vehicle body 3 via a mounting bracket 2, and With the mounting bracket 2 having a cantilever structure in the vehicle body mounted state, the bracket resonance frequency fBR is set to obtain a frequency characteristic sufficiently lower than the sensor resonance frequency fS and the vehicle body resonance frequency fB. Therefore, the influence of the vehicle body vibration generated on the vehicle body 3 on the angular velocity sensor 1 during traveling is suppressed to a small level, the sensor output value offset in the sensor resonance frequency fS region is suppressed to a small level, and the angular velocity can be accurately detected.

(2) With the sensor resonance frequency fS unchanged, the bracket resonance frequency fBR is set sufficiently lower than the sensor resonance frequency fS by setting the bracket resonance frequency fBR having a high degree of freedom in setting the resonance frequency depending on the setting of the beam structure. Since the frequency characteristics are set so as to be obtained, it is possible to easily provide a vehicle body mounting structure of a vehicle angular velocity sensor capable of accurately detecting an angular velocity.

(3) The shape of the mounting bracket 2 is such that the sensor case 1a and the mounting bracket 2 are mounted on the vehicle body.
Since it has a cantilever structure and has a case fixing part 2a and a mounting extension part 2b extending from the case fixing part 2a in only one direction, the structure is simple and cost effective. Is advantageous to.

The same effect can be obtained by adjusting the sensor resonance frequency fS to the high frequency side instead of adjusting the bracket resonance frequency fBR to be low while keeping the sensor resonance frequency fS as it is. .

(Second Embodiment) First, the structure will be described.

FIG. 7 is a side view showing the vehicle body mounting structure of the vehicle angular velocity sensor of the second embodiment of the present invention.

In FIG. 7, 1 is an angular velocity sensor, 2'is a mounting bracket, 3 is a vehicle body, 4 is a connector, and 5 is a screw.

The mounting bracket 2'is fixed to the vehicle body 3 by means of screws 5, and the shape of the mounting bracket 2'is a doubly supported beam structure in which the sensor case 1a and the mounting bracket 2'are mounted in the vehicle body. To have
It is formed to have a case fixing portion 2a, and a first attachment extension portion 2b and a second attachment extension portion 2c extending vertically from the case fixation portion 2a.

Then, as shown in FIG. 7, in a state where the angular velocity sensor 1 is fixed to the vehicle body 3 via the mounting bracket 2, the bracket resonance frequency fBR of the mounting bracket 2'is fS as the sensor resonance frequency, fdamp. When the vibration proof system resonance frequency of the detector and fpin are the support pin resonance frequencies, fdamp <fBR <fpin or fdamp <fBR <fs
(However, fdamp <fpin <fs) is set.

The rest of the structure is the same as that of the structure of the first embodiment, and therefore its explanation is omitted.

Next, the operation will be described.

As shown in FIG. 2, in an angular velocity sensor installed in a vehicle, in order to reduce the level of disturbance vibration generally transmitted to the detection unit 1c, a constant mass is provided in the detection unit case 1b housing the detection unit 1c. Is added to the sensor case 1a via a vibration-proof rubber 1d.
In this case, in addition to the tuning fork drive resonance frequency shown in FIG. 3, the following two factors can be considered as factors that cause the sensor output value to largely offset. (1) The detector 1c and the detector case 1b are a mass, and the vibration isolation rubber 1d is a spring. The tuning fork vibrating pieces 10 to 14 are fixed to the case 1b.
Is the mass, and the offset is due to the support pin resonance frequency in which the support pin 15 serves as a spring. In this case, the frequency characteristic of the sensor output offset is shown in FIG.
become that way. In FIG. 8, fdamp is the resonance frequency of the vibration proof system of the detector, and fpin is the resonance frequency of the support pin.

As described above, when the sensor outputs are largely offset at two or more resonance frequencies, the bracket resonance frequency fBR in the vehicle mounted state is set so as to avoid the resonance frequency peculiar to the sensor as shown in FIG. To do.

FIG. 9 shows the case of fdamp <fBR <fpin and the case of fdamp <fBR <fS by a solid line and a broken line, respectively.

This frequency adjustment is performed as shown in FIG.
This can be achieved by adjusting the rigidity in a vehicle body mounted state by a mounting bracket 2'having a doubly supported beam structure for fixing the upper and lower ends of the sensor to the vehicle body 3.

Next, the effect will be described.

The following effects are added to the effects of the first embodiment.

With the mounting bracket 2'having a shape of a doubly supported beam, the bracket resonance frequency fBR of the mounting bracket 2'is fdamp <f in the state of being mounted on the vehicle body.
Since the structure is set so that BR <fpin or fdamp <fBR <fs, the sensor resonance frequency fS
The sensor output value offset is suppressed to a small value not only in the region but also in the detection unit anti-vibration system resonance frequency fdamp region and the support pin resonance frequency fpin region, and the angular velocity can be detected more accurately.

Even if the bracket resonance frequency fBR is set to be lower than the detection unit anti-vibration system resonance frequency fdamp, the above effects can be obtained.

Although the embodiments have been described above with reference to the drawings, the specific structure is not limited to the embodiments, and modifications and additions within the scope of the present invention are included in the present invention. Be done.

For example, in the embodiment, an example in which the mounting bracket has a flat plate shape is shown, but it may have a wavy shape so that the required resonance frequency can be easily set.

[0053]

As described above, according to the present invention, in the vehicle body mounting structure of the vehicle angular velocity sensor used as the input sensor of the vehicle-mounted control system that uses the angular velocity as input information, the mounting of the angular velocity sensor to the vehicle body is performed. The bracket is shaped so that the sensor case and the mounting bracket have a beam structure when mounted on the vehicle body, and the resonance frequency of the mounting bracket is detected by the sensor when the angular velocity sensor is fixed to the vehicle body through the mounting bracket. Since the vehicle body mounting structure is characterized in that it is set to be lower than the drive resonance frequency of the section, the influence of the vehicle body vibration that occurs on the vehicle body during traveling on the angular velocity sensor can be suppressed to a small degree, and the angular velocity can be accurately detected. The effect of being able to be obtained is obtained.

[Brief description of drawings]

FIG. 1 is a side view showing a vehicle body mounting structure of a vehicle angular velocity sensor according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a vehicle angular velocity sensor of the first embodiment and a sensor unit in a controller.

FIG. 3 is a frequency characteristic diagram of sensor output values according to a conventional sensor mounting structure.

FIG. 4 is a frequency characteristic diagram of vehicle body resonance.

FIG. 5 is a frequency characteristic diagram of the mounting bracket of the first embodiment structure.

FIG. 6 is a frequency characteristic diagram of a sensor output value according to the structure of the first embodiment.

FIG. 7 is a side view showing a vehicle body mounting structure of a vehicle angular velocity sensor according to a second embodiment of the present invention.

8 is a frequency characteristic diagram of a sensor output value by the angular velocity sensor shown in FIG.

FIG. 9 is a frequency characteristic diagram of the mounting bracket of the second embodiment structure.

FIG. 10 is a side view showing a vehicle body mounting structure of a conventional vehicle angular velocity sensor.

[Explanation of symbols]

 1 Angular velocity sensor 1a Sensor case 1b Detection part case 1c Detection part 2 Mounting bracket 3 Car body 4 Connector 5 Screw

Claims (3)

[Claims] 1. A vehicle body mounting structure of an angular velocity sensor for a vehicle, wherein an angular velocity sensor for detecting an angular velocity generated in a vehicle is mounted on a vehicle body, wherein a shape of a mounting bracket for mounting the angular velocity sensor on the vehicle body is a vehicle body mounted state, and a sensor case is provided. And the mounting bracket is formed to have a beam structure, and the resonance frequency of the mounting bracket is set to be lower than the drive resonance frequency of the sensor detection unit with the angular velocity sensor fixed to the vehicle body via the mounting bracket. A body mounting structure for an angular velocity sensor for a vehicle, which is characterized in that 2. The mounting bracket is fixed to one side surface of the angular velocity sensor, and the mounting bracket is formed so that the sensor case and the mounting bracket have a cantilever structure in a vehicle body mounted state. The vehicle body mounting structure for a vehicle angular velocity sensor according to claim 1. 3. The mounting bracket is fixed to one side surface of the angular velocity sensor, and the mounting bracket is shaped so as to have a doubly supported beam structure in the sensor case and the mounting bracket in a vehicle body mounted state. The vehicle body mounting structure for a vehicle angular velocity sensor according to claim 1.