JP4337943B2 - Rotation rate sensor - Google Patents

Description

  The present invention relates to a rotation rate sensor.

As a vibrating gyroscope as a rotation rate sensor, for example, one as shown in Patent Document 1 is known. In this vibrating gyroscope, the vicinity of the node point of the vibrator is supported by a thin U-shaped line, and both ends of the line are fixed to a rectangular mounting board made of glass epoxy or the like. Further, the mounting substrate is held and fixed on the base plate at the node point portion of the vibration mode of the mounting substrate generated by the vibration of the vibrator.
Japanese Patent Laid-Open No. 11-287658

  Such a vibration gyro is intended to isolate vibrations by reducing the resonance frequency of the entire system by a mechanical filter effect, so the U-shaped thin line supports the vicinity of the node point of the vibrator. Must. However, since the support method using such a thin line is extremely complicated, it has a problem that it is not reliable and is extremely weak against impact application.

  The present invention has been made to solve this problem, and it is an object of the present invention to provide a highly reliable rotation rate sensor and multi-axis detection type rotation rate sensor that are strong against impact application.

In order to achieve the above object, the present invention relates to a sensing element, electrically connected to the sensing element, driving the sensing element at a resonance frequency in a driving direction, and adjusting the rotation rate obtained from the sensing element. A rotation rate sensor having a circuit unit that adjusts and outputs a corresponding signal, a container in which the detection element is housed, and an elastic body attached to the container, wherein the elastic body has electrical conductivity. Resonance frequency in the direction in which the peak frequency of the resonance frequency in the transfer characteristic curve of the support system of the rotation rate sensor including the elastic body is an elastic body in which a thin line is embedded, in the direction in which the detection element is driven and the rotation rate is detected And the peak frequency of the resonance frequency in the transfer characteristic curve of the support system is the difference between the resonance frequency in the driving direction of the sensing element and the resonance frequency in the direction of detecting the rotation rate. Greater than the detuning frequency and the cut-off frequency of the low-pass filter in the circuit portion, in which a small turnover sensor than the detuning frequency.

  With such a configuration, it is possible to realize a rotation rate sensor that is strong against impact application and has high reliability.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS.

(Embodiment 1)
FIG. 1 is a perspective view of a rotation rate sensor according to Embodiment 1 of the present invention. FIG. 2 shows an AA cross-sectional view of the sensor shown in FIG. FIG. 3 is a perspective view for explaining the vibrator constituting the sensor. FIG. 4 shows a resonance characteristic diagram of the vibrator. FIG. 5A shows a frequency spectrum diagram for explaining a modulation side wave in the vicinity of the drive side resonance frequency (fd) when rotation of the frequency fω is applied around the Y axis of the same vibrator. FIG. 5B shows a characteristic diagram of the low-pass filter in the circuit section of the sensor. FIG. 5C shows a frequency-gain characteristic diagram of the output after passing through the low-pass filter when a rotation rate corresponding to the detuning frequency A is applied around the Y axis of the same vibrator. FIG. 6A shows a resonance characteristic diagram of the vibrator, and FIG. 6B shows a mechanical frequency-gain characteristic diagram (support system transfer characteristic diagram) of the support system of the sensor. FIG. 7 is an explanatory diagram for explaining a state in which a disturbance impact is applied when the sensor is mounted on the substrate. FIG. 8A shows an explanatory diagram for explaining the dimensional relationship between the hermetic container and the elastic body. FIG. 8B shows a correlation diagram between the dimensions of the airtight container and the elastic body shown in FIG. FIG. 9 shows a mechanical frequency-gain characteristic diagram (support system transmission characteristic diagram) in another design specification of the support system of the sensor shown in FIG. FIG. 10A is an explanatory diagram showing a change in the rotation rate applied to the sensor, and FIG. 10B is an output from the circuit unit corresponding to the change in the rotation rate shown in FIG. FIG. 10C is a characteristic diagram showing the relationship between the mass of the detection element of the sensor, the total mass of the circuit unit and the hermetic container, and the amount of output temperature drift.

  In FIG. 1, 1 is a rotation rate sensor, 2 is a rectangular parallelepiped-shaped airtight container made of ceramic or epoxy resin, and 3 is a power supply to the rotation rate sensor 1 provided in the lower part of the airtight container 2. Pad electrode 4 for taking out the output, 4 is silicon rubber as an elastic body integrally formed on the bottom of the airtight container 2, 5 is a pad electrode 3 made of gold or the like and an external electrode provided on the substrate etc. In order to do so, it is a conductor portion provided on the surface of the silicon rubber 4. Silicon rubber 4 as an elastic body may be attached to the bottom of the airtight container 2. In addition, the conductor portions provided on the front and back surfaces of the silicon rubber 4 have at least three electrode functions for power, output, and ground, respectively, and an electrode function that bears output between the power and ground. Therefore, when the sensor is soldered to the substrate, it is possible to reduce the probability of occurrence of a short circuit between the electrode and the ground due to the penetration of the solder.

  The X axis, Y axis, and Z axis shown in FIG. 1 are the width direction, the longitudinal direction, and the thickness direction of the hermetic container 2, respectively.

  In FIG. 2, 6 is a quartz tuning fork vibrator as a detecting element, 7 is a layered wiring provided inside the hermetic container 2, 8 is a drive control of the quartz tuning fork vibrator 6 at a resonance frequency in the driving direction, A circuit unit for adjusting and outputting a signal according to the rotation rate obtained from the quartz tuning fork vibrator 6, and a base 10a for supporting and fixing the quartz tuning fork vibrator 6 using an adhesive or the like, 10a, Reference numeral 10b denotes a lid made of metal or the like. The circuit unit 8 is made of, for example, a semiconductor bare chip, and is connected to a pad electrode (not shown) provided in the hermetic container 2 by wire bonding or bumps. In addition, after the gas is filled in the hermetic container 2, the hermetic container 2 is sealed by welding or bonding with the lids 10 a and 10 b in order to keep the hermetic container 2 hermetic.

  In FIG. 3, the quartz tuning fork vibrator 6 is formed by directly joining two quartz plates at the level of interatomic coupling. Reference numerals 11 and 12 denote arms of the crystal tuning fork type vibrator 6, reference numeral 13 denotes a base for connecting the arms 11 and 12, reference numeral 14 denotes electrodes for driving a tuning fork formed by depositing chromium and gold on the arms 11 and 12 (not shown). ) And a pad electrode formed by vapor-depositing chromium and gold respectively connected to electrodes (not shown) for detecting a signal corresponding to the rotation rate. The pad electrode 14 is connected to a pad electrode (not shown) provided in the hermetic container 2 by wire bonding or bumps. Since there is no beam structure or constriction structure for separating vibration at the base 13, a crystal tuning fork type vibrator is also applied to a drop impact (impact instantaneously exceeding 10,000 G) from 1 m above the concrete surface. 6 is not damaged.

  In FIGS. 1 to 3, when a drive signal is supplied from the circuit unit 8 to the pad electrode 14 on the crystal tuning fork vibrator 6, the arms 11 and 12 reciprocate in the X-axis direction. When the rotation rate ω is applied around the Y axis, the force (Coriolis force) acting in the cross product direction (Z axis direction) of the amplitude velocity vector and the rotation rate vector is proportional to the mass of the arms 11 and 12. The arms 11 and 12 bend in the direction of detecting the rotation rate (Z-axis direction). A signal proportional to the amount of deflection is detected by a detection electrode (not shown) on the quartz tuning fork vibrator 6, and the detected signal is synchronously detected by a drive signal in the circuit unit 8, and the signal after synchronous detection is detected. Is processed by a low-pass filter, and a sensor signal corresponding to the rotation rate can be obtained.

  In FIG. 4, 20 and 21 are resonance frequencies (abbreviated as fd) in the driving direction of the quartz tuning fork vibrator 6 shown in FIG. 3, resonance frequencies (abbreviated as fs) in the direction of detecting the rotation rate, and A is the driving direction. Is a frequency corresponding to the difference between the resonance frequency (fd) and the resonance frequency (fs) in the direction in which the rotation rate is detected (hereinafter referred to as a detuning frequency). The horizontal axis represents frequency, and the vertical axis represents admittance (ease of vibration). Here, 10 kHz is used as fd of the quartz tuning fork vibrator 6. Usually, in order to improve the sensitivity in the direction in which the rotation rate is detected, the dimensional shape of the quartz tuning fork resonator 6 is designed so that fd and fs can be brought close to each other to easily excite vibration in the detection direction. As the detuning frequency A becomes smaller, the quartz tuning fork type vibrator 6 enters a near resonance state and can improve the detection sensitivity. For example, in the case of a navigation system, a rollover system, and an advanced ABS, it is appropriate to set the detuning frequency A to 200 Hz to 400 Hz, 300 Hz to 500 Hz, and 300 Hz to 400 Hz, respectively.

  5A to 5C, reference numerals 22a and 22b denote modulation side waves (fd + fω) and modulation side waves (fd−fω), 23 denotes a frequency fω corresponding to the rotation rate ω, and 24 denotes a low-pass filter. A point indicating the cut-off frequency, 25 is a straight line indicating a gain drop characteristic with respect to the frequency of the low-pass filter, and 26 is a beat component. The horizontal axis is frequency and the vertical axis is gain.

  As shown in FIG. 5A, when a frequency (fω) 23 corresponding to the rotation rate ω is applied around the Y axis of the quartz tuning fork vibrator 6, fd is amplitude-modulated by the frequency (fω) 23, A modulation side wave (fd + fω) 22a and a modulation side wave (fd−fω) 22b are generated above and below fd. The peak amounts of the modulation side wave (fd + fω) 22a and the modulation side wave (fd−fω) 22b are the amplitude amount in the driving direction (X-axis direction) and the mechanical resonance sharpness (Q value) in the detection direction (Z-axis direction). ) And detuning frequency A. By demodulating (detecting and smoothing) the modulation side wave (fd + fω) 22a and the modulation side wave (fd−fω) 22b, a sensor output corresponding to the applied rotation rate can be obtained.

  As shown in FIG. 5B, at the time of demodulation, smoothing is performed by a low-pass filter (a point 24 indicating a cutoff frequency) in order to suppress a noise component that is normally unnecessary. The output after passing through the low-pass filter is set so as to monotonously decrease as the frequency increases according to the straight line 25 indicating the gain drop characteristic with respect to the frequency. For example, the point 24 indicating the cut-off frequency of the low-pass filter is suitably set to 10 Hz, 50 Hz, and 100 Hz, respectively, in the case of a navigation system, rollover system, and advanced ABS. Similarly, the order of the straight line 25 indicating the gain drop characteristic with respect to the frequency of the low-pass filter is second-order to fourth-order, third-order to fourth-order, third-order to fifth-order in the case of the navigation system, rollover system, and advanced ABS.

  As shown in FIG. 5C, when the frequency (fω) 23 of the applied rotation rate is in the vicinity of the detuning frequency A (= fd−fs), for example, the modulation side wave (fd−fω) 22b overlaps with fs. Thus, the modulation side wave (fd−fω) 22b becomes a vibration force, and a vibration level signal that does not correlate with the actual rotation rate is generated in the detection direction (Z-axis direction). When this signal is demodulated, a sharp peak of the sensor output appears at a rotation rate frequency (fω) corresponding to the vicinity of the detuning frequency A (= fd−fs). This is a so-called beat component 26, and is a phenomenon common to resonance-type rotation rate sensors. In principle, this beat component 26 is suppressed by a low-pass filter shown in FIG.

  6A is the same as the resonance characteristic diagram of the vibrator shown in FIG. 4, and FIG. 6B is a mechanical frequency-gain characteristic diagram of the sensor support system (support system transfer characteristic diagram). It is.

  6 (a) and 6 (b), 30 is a support system transmission characteristic curve of a sensor mainly composed of a quartz tuning fork vibrator 6, a circuit unit 8, an airtight container 2 and silicon rubber 4, and 31 is a support system. The peak at the resonance frequency in the transfer characteristic curve 30, 32 is the detuning frequency A (= fd−fs) = fω, and 33 is the attenuation in the vicinity of fd on the support system transfer characteristic curve 30. The resonance frequency 31 is in the range of 2 kHz to 4 kHz, preferably 2 kHz. 6B, the detuning frequency A described in FIGS. 5A to 5C is approximately 200 Hz to 500 Hz, the point 24 indicating the cutoff frequency of the low pass filter is 100 Hz or less, and the order of the low pass filter. Is set to be substantially higher than the third order, and at the same time, it becomes strong against impact application, and at the same time, beats that are likely to occur due to the frequency of the applied rotation rate can be more efficiently suppressed. Reliability is extremely high.

  In FIG. 7, 40 is the impact acceleration in the driving direction (X-axis direction), 41 is the impact acceleration in the direction of detecting the rotation rate (Z-axis direction), and 42 is Y by the impact acceleration of the disturbance regardless of the original rotation rate. An impact rotation moment generated around the axis 43 is a mounting substrate. A silicon rubber 4 integrally formed on the bottom of the hermetic container 2 shown in FIG. 1 is bonded and fixed to the mounting substrate 43.

  This sensor has a quartz tuning fork vibrator 6 as shown in FIG. 3, a mechanical frequency-gain characteristic as shown in FIGS. 6 (a) and 6 (b), and a low-pass circuit as shown in FIG. 5 (c). Since the characteristics of the filter are combined, not only the quartz tuning fork type vibrator 6 is strong against drop impact, but also a frequency (fω) of a rotation rate corresponding to the detuning frequency A (= fd−fs) is applied. Even in this case, the beat component is suppressed. Furthermore, since the resonance frequency peak 31 is set to be larger than the rotation rate frequency (fω) 32 corresponding to the detuning frequency A (= fd−fs), the beat component 26 is not prepared due to mechanical resonance. There is no increase. Further, since the mechanical system attenuation amount 33 in the vicinity of fd is large, it is strong against external impact accelerations 40 and 41 and impact rotation moment 42. For example, when the mass of the rotation rate sensor 1 is 5 grams, the hardness of the silicon rubber 4 is 30 degrees, and the thickness is 0.5 mm, the impact upon dropping onto the concrete surface may be attenuated to less than about 1000G. It has been confirmed.

  8A, a and b are the width of the airtight container 2 (length in the X-axis direction), the thickness of the airtight container 2 (length in the Z-axis direction) and silicon shown in FIGS. 1 and 7, respectively. This is the total thickness of the rubber 4 (the length in the Z-axis direction). An arrow B indicates the direction of an impact acceleration 40 applied to the mounting substrate 43 from the outside in parallel with the width direction (X-axis direction) of the hermetic container 2, and the impact acceleration 40 generates an impact rotation moment 42 around the Y axis.

  In FIG. 8B, when the rotation moment ω ′ around the detection axis when an impact is applied when the a / b ratio shown in FIG. When the b ratio is approximately 1.0 or more, the airtight container gradually becomes substantially flat, and the generation of the rotational moment ω ′ around the detection axis when an impact is applied can be reduced.

  In FIG. 9, reference numeral 34 denotes a mechanical support system for another sensor different from that shown in FIG. A frequency-gain characteristic curve (support system transfer characteristic curve), 35 is a peak at the resonance frequency in the support system transfer characteristic curve 34, and 36 is a detuning frequency A (= fd-fs) = fω. The resonance frequency peak 35 is in the range of 300 Hz to 600 Hz, preferably 500 Hz. Further, the detuning frequency A described in FIGS. 5A to 5C is approximately 1 kHz to 2 kHz, the point 24 indicating the cutoff frequency of the low-pass filter is 100 Hz or less, and the order of the low-pass filter is substantially 3. Even if it is set to the next or higher, it becomes stronger against impact application, and at the same time, beats that are likely to be generated due to the frequency of the applied rotation rate can be more efficiently suppressed, so the output reliability in the detection frequency range of the sensor is high. Become.

  When a rotation rate as shown in FIG. 10A is applied to the sensor, an analog output is generated from the sensor. Since the circuit section of this sensor has a pulse width processing conversion section, a PWM output in which the duty ratio of the pulse width changes as shown in FIG. 10B is generated according to this output. When this output is processed using a microcomputer, an AD converter is not required and only one digital port is required.

  10C, the horizontal axis represents the total mass M of the circuit unit 8 and the airtight container 2 / the mass m of the crystal tuning fork vibrator 6 as the sensing element, and the vertical axis represents the output temperature drift amount of the rotation rate sensor 1 ( deg./sec). As shown in FIG. 10C, when the M / m is 5.0 or more, the vibration of the quartz tuning fork vibrator 6 is stabilized and the amount of leakage vibration is reduced. As a result, the output temperature drift amount of the sensor is also reduced to 10 deg./sec or less.

  Due to the configuration of the present embodiment, even when the sensing element is miniaturized due to the miniaturization of the sensor, the sensor is not subject to deterioration of the characteristics due to manufacturing variations. However, a highly reliable ultra-small rotation rate sensor can be provided at low cost. In particular, a surface mount type rotation rate sensor can be provided at low cost.

  In the present embodiment, an example in which silicon rubber is used as an elastic body has been described. However, the present invention is not necessarily limited to this, and a sheet shape in which fine metal wires are embedded so as to have electrical conductivity in the thickness direction. A sheet made of rubber, urethane, silicon having pores, an elastic material containing a magnetic material or a magnet, fibrous glass, or resin can also be used. Further, the elastic body can have a laminated structure. Furthermore, the structure attached thinly to the surface of an airtight container is also possible.

  In this embodiment, an example using a quartz tuning fork vibrator as a detection element has been described. However, the present invention is not necessarily limited to this, and a silicon plate having a PZT-based piezoelectric film provided on the surface thereof. One-end closed tuning fork vibrator, H-shaped vibrator, beam-type vibrator formed from a silicon plate by etching, ring-shaped vibrator formed from a silicon plate by etching, resonant vibration from a silicon substrate by etching A child arm, a base, a beam supporting the base, and a rectangular frame supporting the beam are integrally formed, and a PZT-based piezoelectric film having a thickness of 1 to 5 μm is deposited on the main surface of the arm. It is possible to use various types of vibrators such as vibrators formed by the above, prisms or cylindrical ceramic vibrators, vibrators using surface acoustic waves, and the like.

  In the present embodiment, an example in which the detection element and the circuit unit are provided at positions separated from each other has been described. However, the present invention is not necessarily limited to this, and is, for example, a one-end closed tuning fork formed from a silicon plate. It is also possible to adopt a configuration in which a circuit is integrally formed on the same surface of the vibrator. By doing so, it becomes easy to reduce the size.

(Embodiment 2)
FIG. 11 is a perspective view of a rotation rate sensor according to Embodiment 2 of the present invention. In FIG. 11, the same components as those in FIG. 1 are denoted by the same reference numerals, detailed description thereof is omitted, and only different portions are described in detail. 11, 4a is silicon rubber as an elastic body in which the silicon rubber 4 shown in FIG. 1 is extended in the Y-axis direction, 5a is a conductor, 50 is a protrusion provided on the silicon rubber 4a, 60 is a mounting substrate, 61 Is a conductor pattern, and 62 is a hole for positioning and storing the protrusion 50 formed on the mounting substrate 60. By providing the protrusion 50 and the hole 62, it is possible to prevent the sensor from being erroneously connected to the substrate while being displaced.

(Embodiment 3)
FIG. 12 is a perspective view of a rotation rate sensor according to Embodiment 3 of the present invention. In FIG. 12, the same components as those in FIG. 1 are denoted by the same reference numerals, detailed description thereof will be omitted, and only different portions will be described in detail. In FIG. 12, reference numeral 70 is a columnar silicon rubber having a circular shape including an ellipse as an elastic body, 5b is a pad electrode 3 made of gold or the like, an external electrode provided on a mounting substrate (not shown), etc. This is a conductor portion provided on the surface of the silicon rubber 70 to connect the two. Silicon rubber 70 is adhered to the bottom of the hermetic container 2, and the silicon rubber 70 is bonded to the mounting substrate. As a result, when the sensor is mounted on the mounting board, a gap is formed between the sensor and the mounting board, and various components can be mounted in the gap, thereby improving the mounting efficiency. .

  In the present embodiment, the columnar body having a circular cross section including an ellipse has been described as the shape of silicon rubber, but various shapes such as a spherical body can be used. Further, although silicon rubber is used as the elastic body, various materials can be used as long as they have elasticity.

(Embodiment 4)
13A is a perspective view of a rotation rate sensor according to Embodiment 4 of the present invention, FIG. 13B is a BB cross-sectional view of the sensor, and FIG. 13C is a resonance characteristic diagram and sensor of the vibrator. FIG. 13D is a characteristic diagram showing the relationship between the thickness of the elastic body and the amount of vibration transmission. In FIG. 13, the same components as those in the first to third embodiments are denoted by the same reference numerals, detailed description thereof is omitted, and only different portions are described in detail.

  In FIG. 13, 80 is a flexible substrate, 80 a is a mounting portion on the flexible substrate 80 on which the rotation rate sensor 1 is mounted, 80 b is a transition portion for drawing wiring from the mounting portion 80 a, and 80 c is for connecting to the mounting substrate 60. The terminal portion of the flexible substrate 80, 81 is a conductor pattern provided on the flexible substrate 80, 82 is a hole provided in the transition portion 80b, 83 is a notch provided in the transition portion 80b, and 84 is on the terminal portion 80c. A first conductor piece 85 connected to the conductor pattern 81, a second conductor piece 85 for positioning and fixing to the mounting substrate 60, and 86 is provided on the flexible substrate 80 so as to correspond to the pad electrode 3. A connection pad, 87 is solder for electrically connecting the pad electrode 3 and the connection pad 86, 88 is silicon rubber as an elastic body, and 88a is Projections consisting Rikongomu, 89 adhesive layer for fixing the silicone rubber 88 to the mounting substrate 60, 90 is a recognition mark.

  The silicon rubber 88 is adhered to the flexible substrate 80, and not only supports the flexible substrate 80 and the rotation rate sensor 1 when mounted on the mounting substrate 60, but also functions as a vibration insulator. Further, although the solder 87 is used to electrically connect the pad electrode 3 and the connection pad 86, a conductive adhesive may be used. In addition, since the adhesive layer 89 is provided, the rotation rate sensor 1 can be easily fixed to the mounting substrate 60. Further, the notch 83 provided in the transition portion 80b is for preventing leakage vibration from the rotation rate sensor 1 from propagating through the flexible substrate 80, and the vibration insulating function of the silicon rubber 88 is flexible substrate. This is to prevent damage caused by the rigidity of the 80 transition portions 80b.

  The second conductor piece 85 is for reinforcing the first conductor piece 84 soldered to the mounting substrate 60 so that no mechanical stress is directly applied. Thereby, it is possible to suppress the disconnection of the first conductor piece 84 or the occurrence of cracks in the soldered portion of the first conductor piece 84 fixed to the mounting substrate 60.

  The first conductor section 84 is assigned a PWM output or an analog output that changes the duty ratio according to the power source, GND, and rotation. More preferably, in consideration of reliability, the first conductor section 84 assigned to supply of power and the first conductor section 84 assigned as GND should not be adjacent to each other.

  The recognition marking 90 is for reducing angular deviation when the rotation rate sensor 1 is mounted with high accuracy.

  In FIG. 13C, 91 is a support system transfer characteristic curve of the sensor, 92 is a 0 dB level in the support system transfer characteristic curve 91, 93 is a first peak at a resonance frequency in the support system transfer characteristic curve 91, and 94 is The attenuation from the level 92 of 0 dB, 95 is the second peak shifted from the peak 93. As shown in FIG. 13 (c), the silicon rubber 88 having a vibration insulating effect can reduce the vibration transmission amount in the vicinity of the resonance frequency (abbreviated as fd) 20 in the driving direction of the quartz tuning fork vibrator 6 in a high frequency region. The attenuation can be suppressed from the level 92 of 0 dB indicated by the broken line to the attenuation 94. Since the vibration leakage is reduced by the attenuation amount 94, the influence of the leakage vibration is reduced. Further, the first peak 93 is the loss, hardness, thickness, shape of the elastic body (here, described by the silicon rubber 88), or the mass m of the sensing element (here, the quartz tuning fork vibrator 6), the outer shape. It is possible to design an arbitrary frequency for various purposes such as avoiding interference with a resonance frequency (abbreviated as fd) 20 determined by the above. For example, when the hardness of the elastic body (here, described by the silicon rubber 88) is increased, the first peak 93 transitions to the second peak 95 side of a higher frequency.

  Further, as shown in FIG. 13D, the attenuation 94 shown in FIG. 13C can be varied by the thickness of the silicon rubber 88.

  As described above, the degree of freedom in vibration isolation design is improved, and it is possible to cope with downsizing, high reliability, and high accuracy.

(Embodiment 5)
FIG. 14A is a perspective view of a rotation rate sensor according to Embodiment 5 of the present invention, and FIG. In FIG. 14, the same components as those in Embodiments 1 to 4 are denoted by the same reference numerals, detailed description thereof is omitted, and only different portions are described in detail.

  In FIG. 14, 100 is a substrate made of glass epoxy as support means, 100a is a hole provided in the substrate 100, 100b is a notch provided in the substrate 100, 100c is a drawer pad provided on the substrate 100, 101 Is a drawer lead formed into a crank mold, and 102 is solder. The lead lead 101 is soldered to the lead pad 100c by solder 102. The notch 100b is for partially reducing the rigidity of the substrate 100 to make it difficult for vibration transmitted from the outside via the lead lead 101 or leakage vibration from the rotation rate sensor 1 to propagate.

  In this embodiment, an example in which soldering is used to connect the lead lead 101 and the lead pad 100c has been described. However, resistance welding or ultrasonic welding can also be used. Furthermore, although the example which uses glass epoxy for the board | substrate 100 was demonstrated, you may use a molding resin, a ceramic-type material, and an inner via-hole type multilayer board | substrate.

  Further, as shown in FIG. 14B, a configuration in which the substrate 100 and the lead 101 are integrated is also possible.

  With the above configuration, cost reduction can be realized.

(Embodiment 6)
FIG. 15A is a perspective view of a rotation rate sensor according to Embodiment 6 of the present invention, and FIG. 15B is a perspective view of a conductor section of the sensor in a linear shape. In FIG. 15, the same components as those in the first to fifth embodiments are denoted by the same reference numerals, detailed description thereof is omitted, and only different portions are described in detail.

  105 is a conductor pattern provided on the substrate 100, 110 is a hole provided in the substrate 100, 111 is a constricted portion provided in a part of the substrate 100 that is elongated, and 112 and 113 are conductor patterns 105 on the substrate 100. Connected conductor segments.

  Since the board | substrate 100 is extended long, the mounting freedom to a various object improves. For example, the rotation rate sensor 1 can be attached to a wall surface of a case (not shown) and connected to a circuit board (not shown) separated from the substrate 100. Moreover, since the hole 110 is provided in the board | substrate 100, it can also be sewn on clothing, shoes, etc. It is also possible to pass a guide pin (not shown) provided on another object through the hole 110 and to fix the guide pin by bending. By comprising in this way, attachment / detachment of the rotation rate sensor 1 becomes easy.

  Further, since the constricted portion 111 is provided in a part of the substrate 100, it is possible to maintain the vibration isolation effect.

  Further, as shown in FIG. 15B, since the conductor piece 113 is linear, the fitting with the connector is easy.

  In this embodiment, an example using a flexible substrate has been described. However, as a support means having a thickness of approximately 0.1 mm to 1 mm by appropriately combining notches, a plurality of holes, a constricted portion, or a thin-walled portion. It is also possible to use a substrate made of hard glass epoxy. By using such a substrate, not only the mountability of the hermetic container is improved, but also various electrical components can be mounted and wire bonding connection to other substrates can be performed.

(Embodiment 7)
FIG. 16 is a perspective view of a multi-axis detection type rotation rate sensor according to Embodiment 7 of the present invention. In FIG. 16, the same components as those in the first to sixth embodiments are denoted by the same reference numerals, detailed description thereof is omitted, and only different portions are described in detail.

  In FIG. 16, 120 is a substrate and 121 is a holder. The two rotation rate sensors 1 are mounted on the substrate 120 so that the rotation detection axis directions ω thereof are the same, and are housed in a holder 121. Thereby, a sensor with redundancy can be constituted.

  By adopting the configuration as in the present embodiment, the resonance frequency in the driving direction of each detection element of the two rotation rate sensors can be made substantially the same, so that each detection element has a resonance frequency different from each other. There is no need to design, and an inexpensive sensor can be realized.

  Further, by arranging the rotation detection axis directions ω of the two rotation rate sensors 1 to be opposite to each other and taking the differential of the outputs of the two rotation rate sensors 1, discrimination such as common noise is possible. Become.

  By configuring as described above, the reliability of the sensor output is remarkably increased, and it is suitable for applications that require high reliability such as automobiles. In addition, there are no restrictions on the shape and cost.

  In the present embodiment, the example in which the rotation detection axis directions ω of the two rotation rate sensors 1 are mounted so as to be the same as each other has been described. It is also possible to mount the rotation rate sensor 1 so that the rotation detection axis directions ω are the same.

(Embodiment 8)
FIG. 17 is a perspective view of a multi-axis detection type rotation rate sensor according to Embodiment 8 of the present invention. In FIG. 17, the same components as those in the first to seventh embodiments are denoted by the same reference numerals, detailed description thereof is omitted, and only different portions are described in detail.

  The two rotation rate sensors 1 are mounted on the substrate 120 so that the rotation detection axis directions ω thereof are orthogonal to each other, and are further housed in a holder 121. With the configuration described above, the vibrations of the two rotation rate sensors 1 are separated, independent, and guaranteed, so that even if they are arranged close to each other, there is no adverse effect such as interference, and high density. It is possible to realize a multi-axis detection type rotation rate sensor mounted on the.

(Embodiment 9)
FIG. 18 is a perspective view of a multi-axis detection type rotation rate sensor according to Embodiment 9 of the present invention. In FIG. 18, the same components as those in the first to eighth embodiments are denoted by the same reference numerals, detailed description thereof is omitted, and only different portions are described in detail.

  In FIG. 18, 130 is a holder made of urethane, 130a and 130b are cavities for embedding two rotation rate sensors 1 whose rotation detection axis directions ω are orthogonal to each other, and 131 is a fixing means provided on the bottom surface of the holder 130 As an adhesive sheet. Since the pressure-sensitive adhesive sheet 131 is provided, it can be efficiently mounted on a substrate other than the substrate such as a set frame. Moreover, although the example using the adhesive sheet 131 has been described in the present embodiment, a magnet such as a magnetic sheet may be used in addition to the adhesive sheet.

  In the present embodiment, the example using the holder 130 made of urethane has been described, but rubber may be used. In addition, the holder 130 is a box shape, but can be various shapes such as a cylindrical shape.

  In this embodiment, an example in which two cavities are provided has been described. However, three or more cavities may be provided depending on applications.

  Due to the configuration of the present embodiment, even when the sensing element is miniaturized due to the miniaturization of the sensor, the sensor is not subject to deterioration of the characteristics due to manufacturing variations. However, a highly reliable ultra-small multi-axis detection type rotation rate sensor can be provided at low cost. In particular, a surface mount type multi-axis detection type rotation rate sensor can be provided at low cost.

  A rotation rate sensor according to the present invention includes a detection element, and a circuit unit for driving and controlling the detection element at a resonance frequency in a driving direction, and adjusting and outputting a signal corresponding to the rotation rate obtained from the detection element. The detection element and the circuit unit are housed, and the detection element and the circuit unit are electrically connected to each other, and at the same time, a ceramic is provided with wiring for transmitting an input / output signal to the circuit unit. Or a resin-made hermetic container, and a conductor portion connected to at least one plane of the outer surface of the hermetic container, and electrically connected to wiring provided on the hermetic container, and further integrated with the hermetic container And a synthetic resonance frequency of a system constituted by the sensing element, the circuit unit, the airtight container and the elastic body is provided in the driving direction of the sensing element. To detect the rotation rate The resonance frequency in the drive direction of the sensing element is greater than the frequency of the applied rotation rate corresponding to the difference between the resonance frequency in the direction of detecting the rotation rate and the low pass filter in the circuit unit. Since the cut-off frequency is made smaller than the frequency of the applied rotation rate corresponding to the difference, it is strong against impact application and has high reliability. Useful for multi-axis detection-type rotation rate sensors that allow multiple sensors to detect each other and prevent multiple sensors from interfering with each other by mounting a plurality of these sensors on a hard substrate using fixing means. It is.

The perspective view of the rotation rate sensor in Embodiment 1 of this invention AA sectional view of the sensor A perspective view for explaining a vibrator constituting the sensor. Resonance characteristics of the same resonator (A) Frequency spectrum diagram of the same vibrator, (b) Characteristic diagram of the low-pass filter in the circuit section of the sensor, and (c) Frequency-gain characteristic diagram of output after passing through the low-pass filter of the same vibrator. (A) Resonance characteristic diagram of the vibrator, (b) Support system transmission characteristic diagram of the sensor Explanatory drawing for demonstrating how the disturbance shock of the sensor is applied (A) Explanatory drawing for demonstrating the dimensional relationship of an airtight container and an elastic body, (b) Correlation figure of the dimension and rotation rate of the airtight container and an elastic body Support system transmission characteristics of another sensor (A) Explanatory drawing which shows the mode of the change of the rotation rate applied to the sensor, (b) Output figure for demonstrating the PWM output output from a circuit part, (c) Mass and output temperature drift of the sensor Characteristic diagram showing the relationship with quantity The perspective view of the rotation rate sensor in Embodiment 2 of this invention The perspective view of the rotation rate sensor in Embodiment 3 of this invention (A) Perspective view of rotation rate sensor according to embodiment 4 of the present invention, (b) BB cross-sectional view of the sensor, (c) Resonance characteristic diagram and support system transmission characteristic diagram of vibrator, (d) Elasticity Characteristic diagram showing the relationship between body thickness and vibration transmission (A) Perspective view of a rotation rate sensor according to Embodiment 5 of the present invention, (b) Perspective view of a state in which a substrate of the sensor and a lead are integrated. (A) Perspective view of a rotation rate sensor according to Embodiment 6 of the present invention, (b) Perspective view of a state in which the conductor section of the sensor is linear. The perspective view of the multi-axis detection type | mold rotation rate sensor in Embodiment 7 of this invention. The perspective view of the multi-axis detection type rotation rate sensor in Embodiment 8 of this invention. The perspective view of the multi-axis detection type | mold rotation rate sensor in Embodiment 9 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rotation rate sensor 2 Airtight container 3, 14 Pad electrode 4, 4a, 70, 88 Silicon rubber 5, 5a, 5b Conductor part 6 Crystal tuning fork type vibrator 7 Wiring 8 Circuit part 9 Base 10a, 10b Lid 11, 12 Arm 13 Base 20 resonance frequency fd
21 Resonance frequency fs
22a Modulation side wave (fd + fω)
22b Modulation side wave (fd-fω)
23 Frequency fω
24 Point indicating cutoff frequency 25 Straight line indicating gain drop characteristic 26 Beat component 30 Support system transfer characteristic curve 31 Peak at resonance frequency in support system transfer characteristic curve 30 32, 36 Detuning frequency A (= fd−fs) = fω
33 Attenuation amount in the vicinity of fd 34 Support system transfer characteristic curve of another sensor 35 Peak at resonance frequency in support system transfer characteristic curve 34 Impact acceleration in drive direction (X-axis direction) 41 Direction for detecting rotation rate (Z-axis) Direction of impact acceleration 42 Impact rotation moment generated around Y axis 43, 60 Mounting substrate 50, 88a Protrusion 61, 81, 105 Conductor pattern 62, 82, 100a, 110 Hole 80 Flexible substrate 80a Mounting portion 80b Transition portion 80c Terminal Part 83, 100b Notch 84 First conductor segment 85 Second conductor segment 86 Connection pad 87, 102 Solder 89 Adhesive layer 90 Recognizing marking 91 Sensor support system transfer characteristic curve 92 0 dB in support system transfer characteristic curve 91 Level 93 at resonance frequency in support system transfer characteristic curve 91 1 peak 940 dB attenuation from level 92 95 second peak shifted from peak 93 100, 120 substrate 100c extraction pad 101 extraction lead 111 constricted portion 112, 113 conductor section 121, 130 holder 130a, 130b cavity 131 adhesive Sheet

Claims (2)

A sensing element;
Electrically connected to the sensing element;
While driving the sensing element at a resonance frequency in the driving direction,
A circuit unit for adjusting and outputting a signal corresponding to the rotation rate obtained from the sensing element;
A container in which the sensing element is housed,
An elastic body attached to the container;
A rotation rate sensor comprising:
The elastic body is an elastic body embedded with fine wires having electrical conductivity,
The peak frequency of the resonance frequency in the transfer characteristic curve of the support system of the rotation rate sensor including the elastic body is smaller than the resonance frequency in the direction of detecting the drive direction and the rotation rate of the sensing element,
And the peak frequency of the resonance frequency in the transfer characteristic curve of the support system is
Greater than the detuning frequency, which is the difference between the resonant frequency in the driving direction of the sensing element and the resonant frequency in the direction of detecting the rotation rate,
A rotation rate sensor in which a cutoff frequency of a low-pass filter in the circuit unit is smaller than the detuning frequency. The peak frequency of the resonance frequency in the transfer characteristic curve of the support system is 2 kHz to 4 kHz,
The resonant frequency in the driving direction of the sensing element is 10 kHz or more,
The detuning frequency is 200 Hz to 500 Hz,
The cutoff frequency of the low-pass filter is 100 Hz or less,
The rotation rate sensor according to claim 1, wherein the order of the low-pass filter is substantially equal to or higher than the third order.

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