JP2009229071A - Angular velocity sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an angular velocity sensor capable of reducing the number of components and man-hours for assembly. <P>SOLUTION: In this angular velocity sensor, a circuit board 44 is clamped between a support part 55 on a mounting strut 54 of a case 22 and a support part 59 on a mounting strut 58 of a cover 57, and a case 50 is constituted of a light-absorbing material, and the cover 57 is constituted of a light-transmissible material. Hereby, a surface part of the light-absorbing material is melted by heat energy using a laser or the like, to thereby allow adhesion to the light-transmissible material, and consequently, the number of components and assembly man-hours for the angular velocity sensor can be reduced. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an angular velocity sensor used for detecting the behavior of a vehicle body, particularly in a vehicle body control device for an automobile.

  A conventional angular velocity sensor of this type will be described with reference to the drawings. FIG. 13 is an exploded perspective view of a conventional angular velocity sensor, and FIG. 14 is an exploded perspective view showing a state in which a vibrator and a circuit board are attached to a base in the angular velocity sensor.

  13 and 14, reference numeral 1 denotes a vibrator. The vibrator 1 is attached to a support base 2, and a metal terminal bar 3 is provided on the support base 2 upward. Reference numeral 4 denotes a base. The base 4 has the support base 2 attached to the upper surface, cable insertion holes 5, and recesses 6 at the four corners. Reference numeral 7 denotes an anti-vibration rubber. The anti-vibration rubber 7 is attached to the recess 6 in the base 4 and has a through hole 8 from the upper surface to the lower surface. Reference numeral 9 denotes a circuit board. The circuit board 9 has mounting holes 10 at four corners, a cable insertion hole 12 on one side, and a processing circuit 13 on the upper surface. One of the cables 11 is inserted into a cable insertion hole 5 provided in the base 4, and the other is inserted into a cable insertion hole 12 provided in the circuit board 9. Reference numeral 14 denotes a resin case. The case 14 accommodates the vibrator 1, the base 4 and the circuit board 9 inside, and is inserted into the through-hole 8 in the vibration-proof rubber 7 and the mounting hole 10 in the circuit board 9. In addition, the mounting column 16 having the support portion 15 is provided upward from the inner bottom surface, and the tip of the mounting column 16 is heat caulked to fix the base 4 and the circuit board 9. The case 14 is provided with openings 17 and screw holes 18 are provided at the four corners of the openings 17. Reference numeral 19 denotes a cover. The cover 19 closes the opening 11 in the case 14, and is provided with holes 19a at four apexes. A screw 20 is attached to the case 14 by screwing the screw 20 into the screw hole 18 of the case 14 through the hole 19a of the cover 19.

  Next, the operation of the conventional angular velocity sensor configured as described above will be described.

  This angular velocity sensor is a gyroscope that utilizes a dynamic phenomenon that when a rotational angular velocity is applied to the vibrator 1, a Coriolis force is generated in a direction perpendicular to the vibration direction.

  First, when an AC voltage converted by the processing circuit 13 of the circuit board 9 is applied to a drive electrode (not shown) of the vibrator 1 from an external power supply (not shown), the vibrator 1 is bent and vibrated. In this state, when the vibrator 1 rotates at the angular velocity ω around the central axis in the longitudinal direction of the vibrator 1, a Coriolis force of F = 2 mv × ω is generated in the vibrator 1. By this Coriolis force, an output signal composed of electric charges generated at the detection electrode (not shown) is converted into an output voltage by the processing circuit 13 of the circuit board 9 and input to a counterpart computer (not shown). The angular velocity is detected.

As prior art document information relating to the invention of this application, for example, Patent Document 1 is known.
JP-A-9-14971

  However, in the conventional angular velocity sensor described above, when the cover 19 is attached to the case 14, the base 4 and the circuit board 9 are sequentially inserted into the attachment column 16 of the case 14 and fixed by heat caulking, and further to the case 14. Since the cover 19 is attached with the screws 20, there is a problem that the number of parts and the number of assembling steps increase.

  The present invention solves the above-described conventional problems, and an object thereof is to provide an angular velocity sensor that can reduce the number of parts and the number of assembly steps.

  In order to achieve the above object, the present invention has the following configuration.

  According to a first aspect of the present invention, there is provided a vibrator, a processing circuit that drives the vibrator to be vibrated, converts charges generated by the Coriolis force from the vibrator into an output signal, and the processing circuit on the top surface. Alternatively, a circuit board provided on the lower surface and provided with at least two attachment holes, and an attachment column having a support portion and being inserted into the attachment hole of the circuit board and accommodating the vibrator and the circuit board inside. A case provided upward from the inner bottom surface and having an opening, and a cover that closes the opening of the case and is provided with a mounting column having a support portion at a position facing the mounting column of the case. The circuit board is sandwiched between the support portion of the mounting column of the case and the support portion of the mounting column of the cover. One is made of a light transmissive material and the other is made of a light absorptive material. According to this structure, one of the case and the cover is made of a light transmissive material and the other is made of light. Since it is composed of an absorptive material, it can be bonded to the light transmissive material by melting the surface of the light absorptive material with thermal energy using a laser, etc. Since it is not necessary to fix the circuit board to the mounting column of the case by caulking and to attach the cover to the case with screws, there is an effect that the number of parts of the angular velocity sensor and the number of assembly steps can be reduced. .

  In the invention according to claim 2 of the present invention, in particular, an insertion recess is provided in one of the case mounting column and the cover mounting column, and a columnar part is provided in the other. In this structure, the insertion recess is provided in one of the case mounting column and the cover mounting column, and the columnar part is provided in the other. Since the circuit board is clamped by inserting the cylindrical portion into the insertion recess, the circuit board can be securely clamped by the mounting column of the case and the mounting column of the cover, and the case and the cover are firmly It has the effect that it can fix to.

  According to the third aspect of the present invention, in particular, the circuit board is sandwiched by bringing the tip of the mounting column of the case and the tip of the mounting column of the cover into contact with each other. Since the tip of the case mounting column and the tip of the cover mounting column are in contact with each other, the circuit board can be securely held between the case mounting column and the cover mounting column. As a result, the case and the cover can be firmly fixed with a simple structure.

  As described above, the angular velocity sensor of the present invention includes a vibrator, a vibrator that drives the vibrator, and a processing circuit that converts electric charges generated by the Coriolis force from the vibrator into an output signal. A circuit board provided on the lower surface and provided with at least two or more mounting holes, and a mounting column having a support portion that is inserted into the mounting hole of the circuit board and accommodates the vibrator and the circuit board inside. A case provided upward from the bottom and having an opening, and a cover that closes the opening of the case and is provided with a mounting post having a support at a position facing the mounting post of the case, The circuit board is sandwiched between the support portion of the mounting column of the case and the support portion of the mounting column of the cover. Since one of them is made of a light-transmitting material and the other is made of a light-absorbing material, the light-transmitting material is melted by heat energy using a laser, etc. Since it is not necessary to fix the circuit board to the mounting column of the case by heat caulking and attach the cover to the case with screws as in the conventional case, the number of parts of the angular velocity sensor can be increased. This has the excellent effect of reducing the number of assembly steps.

  Hereinafter, an angular velocity sensor according to an embodiment of the present invention will be described with reference to the drawings.

  1 is an exploded perspective view of an angular velocity sensor according to an embodiment of the present invention, FIG. 2 is a side sectional view of the angular velocity sensor, FIG. 3 is a perspective view showing a state where a cover is removed from the angular velocity sensor, and FIG. 5 is an exploded perspective view of the element portion in the angular velocity sensor, FIG. 5 is a perspective view of the vibrator in the angular velocity sensor, FIG. 6 is a side sectional view of the first arm portion in the vibrator of the angular velocity sensor, and FIG. FIG. 8 is a perspective view of the vibrator case as seen from the back side in the angular velocity sensor.

  1 to 8, reference numeral 21 denotes an element portion. As shown in FIG. 4, the element portion 21 closes the vibrator 22, a vibrator case 23 that houses the vibrator 22, and the vibrator case 23. And a cover 24. As shown in FIG. 5, the vibrator 22 includes a first arm portion 25, a second arm portion 26, and a connection portion 27 that connects the first arm portion 25 and one end of the second arm portion 26. It is comprised by. Further, as shown in FIG. 6, the vibrator 22 is provided with a common GND electrode 29 made of an alloy thin film of Pt and Ti over the entire upper surface of the base material 28 made of Si, and further on the upper surface of the common GND electrode 29. A piezoelectric layer 30 made of a PZT thin film is provided. Further, as shown in FIG. 5, the tuning-fork-shaped vibrator 22 is positioned approximately inside the center of the upper surface, provided with a pair of first drive electrodes 31a on the upper surface of the piezoelectric layer 30, and substantially at the center. A pair of second drive electrodes 31 b are provided on the upper surface of the piezoelectric layer 30. Further, the vibrator 22 is located on the tip side of the upper surface, provided with a pair of detection electrodes 32 on the upper surface of the piezoelectric layer 30, and located closer to the root side than the first drive electrode 31a and the second drive electrode 31b. The monitor electrode 33 is provided on the upper surface of the piezoelectric layer 30. In addition, a GND electrode 34 is provided on the surface of the piezoelectric layer 30 so as to be positioned on the surface of the connection portion 27 in the vibrator 22.

  The vibrator case 23 is made of ceramic, and the vibrator case 23 is provided with a multilayer circuit board 35 having a layer structure of ceramic and a wiring conductor from the inner bottom surface to the outer bottom surface. As shown in FIG. 8, a power supply electrode 36 made of Ag, a GND electrode 37, an output electrode 38, and three fixing electrodes 39 are provided on the outer bottom surface of the multilayer circuit board 35 in FIG. A side wall 40 made of ceramic is provided over the outer periphery of the upper surface of the circuit board 35, and a metal frame 41 made of kovar is provided on the upper surface of the side wall 40.

  Further, as shown in FIG. 7, a step portion 42 is provided on the inner bottom surface of the vibrator case 23, and the connection portion 27 of the vibrator 22 is fixed to the step portion 42. Wiring electrodes 43 are provided on both sides to which 27 is fixed, and the wiring electrodes 43 are connected to the first driving electrode 31a and the second driving electrode 31 in the vibrator 22 via wire wires (not shown). The drive electrode 31b, the detection electrode 32, the monitor electrode 33, and the GND electrode 34 are electrically connected. An opening (not shown) in the vibrator case 23 is sealed with a cover 24 so that the inside of the vibrator case 23 is in a vacuum atmosphere.

  44 is a circuit board. The circuit board 44 is provided with an output electrode hole 45, a power electrode hole 46 and a GND electrode hole 47 made of a through-hole electrode on a straight line on one side from the upper side to the lower side, and the output electrode. The hole 45 is electrically connected to the output electrode 38 in the vibrator case 23 via the processing circuit 48. The power electrode hole 46 in the circuit board 44 is electrically connected to the power electrode 36 in the vibrator case 23, and the GND electrode hole 47 is electrically connected to the GND electrode 37 in the vibrator case 23. Yes. The circuit board 44 is provided with mounting holes 49 located in the vicinity of the four apexes. Further, a processing circuit 48 made of an IC is provided on the upper surface of the circuit board 44, and this processing circuit 48 processes an output signal output from the output electrode 38 in the vibrator case 23.

50 is a bottomed cylindrical resin case made of a light-absorbing material. The case 50 accommodates the circuit board 44 inside, is provided with an opening 50a, and has a coefficient of thermal expansion of 19. The output connector terminal 51, the power connector terminal 52, and the GND connector terminal 53 made of brass of 3 × 10 ⁻⁶ [1 / ° C.] are arranged in a straight line on one end side, and the other end side protrudes outward. As such, they are integrally provided. One end side of the power connector terminal 52 in the case 50 is inserted into the power electrode hole 46 in the circuit board 44 and fixed by soldering, and one end side of the output connector terminal 51 is inserted into the output electrode hole 45. And fixed by soldering. The GND connector terminal 53 is also inserted through the GND electrode hole 47 and fixed by soldering in the same manner as these. Further, the case 50 is provided with mounting posts 54 integrally formed in the vicinity of the four apexes of the inner bottom surface. Further, as shown in FIG. A portion 55 is provided, and a columnar portion 56 to be inserted into the mounting hole 49 in the circuit board 44 is provided.

  57 is a resin cover made of a light-transmitting material, and this cover 57 closes the opening 50a in the case 50. The cover 57 includes a mounting post 54 in the case 50 and A mounting column 58 is provided at the opposite position, a support portion 59 is provided at the tip of the mounting column 58, and an insertion recess 60 is provided inside. Then, the cylindrical portion 56 of the attachment column 54 of the case 50 is attached to the cover 57 so that the circuit board 44 is sandwiched between the support portion 55 of the attachment column 54 of the case 50 and the support portion 59 of the attachment column 58 of the cover 57. It is inserted into the insertion recess 60 in the column 58.

  Next, a method for assembling the angular velocity sensor according to the embodiment of the present invention configured as described above will be described.

  First, as shown in FIG. 9B, a common GND electrode 29 made of an alloy thin film of Pt and Ti is formed on the upper surface of the base material 28 made of Si shown in FIG. As shown in FIG. 9C, a piezoelectric layer 30 made of a PZT thin film is formed on the upper surface of the common GND electrode 29 by vapor deposition.

  Next, as shown in FIG. 9D, a forming electrode 33a made of an alloy thin film of Ti and Au is formed on the upper surface of the piezoelectric layer 30 by vapor deposition, and then, as shown in FIG. The unnecessary portions of the common GND electrode 29, the piezoelectric layer 30, and the forming electrode 33a are removed so that the first driving electrode 31a, the second driving electrode 31b, and the detection electrode are formed on the upper surface of the piezoelectric layer 30. 32, a monitor electrode 33 and a GND electrode 34 are formed.

  Next, a voltage is applied to the common GND electrode 29 side, and the first drive electrode 31a, the second drive electrode 31b, the detection electrode 32, the monitor electrode 33, and the GND electrode 34 are grounded, whereby the piezoelectric layer 30 is formed. Polarize.

  Next, by removing unnecessary portions on the base material 28, the individual vibrators 22 are formed as shown in FIG.

  Next, a wiring electrode 43 made of Au is formed on the upper surface of the multilayer circuit board 35 made of an insulator (not shown) made of ceramic and a conductor for wiring (not shown) and a stepped portion 42 prepared in advance, Thereafter, a power electrode 36 made of Ag, a GND electrode 37, an output electrode 38, and three fixing electrodes 39 are formed on the lower surface of the multilayer circuit board 35.

  Next, a side wall 40 made of ceramic is formed over the outer periphery of the upper surface of the multilayer circuit board 35, and then a metal frame 41 made of Kovar is fixed to the upper surface of the side wall 40.

  Next, the lower surface of the connection portion 27 in the tuning fork type vibrator 22 is fixed to the upper surface of the step portion 42 of the vibrator case 23, and then the first drive electrode 31 a and the second drive electrode 31 a formed on the upper surface of the vibrator 22. The drive electrode 31b, the detection electrode 32, the monitor electrode 33, the GND electrode 34 and the wiring electrode 43 in the vibrator case 23 are electrically connected to each other by wire bonding through a wire wire (not shown) made of aluminum.

  Next, a metal cover 24 is fixed to the opening of the vibrator case 23 by seam welding.

  Next, the element part 21 is placed on the upper surface of the circuit board 44 so that the power supply electrode 36, the GND electrode 37, the output electrode 38 and the fixing electrode 39 in the element part 21 are electrically connected to the circuit board 44. To do.

  Next, after the processing circuit 48 is placed on the upper surface of the circuit board 44, the element portion 21 and the processing circuit 48 are soldered on the upper surface of the circuit board 44 by passing the circuit board 44 through a reflow furnace (not shown). Attach.

  Next, a mounting post 54 having a support portion 55 and a columnar portion 56 and its distal end portion 61 is provided in advance upward from the inner bottom surface, and an output connector terminal 51, a power connector terminal 52, and a GND connector terminal. With the 53 inserted, the case 50 is formed of a resin using a light absorbing material.

  Next, a mounting hole 49, an output electrode hole 45, a power electrode hole 46, and a GND electrode hole 47 in the circuit board 44 are formed in the mounting column 54, the output connector terminal 51, the power connector terminal 52, and the GND connector terminal 53 in the case 50, respectively. Insert.

  Next, the output electrode hole 45, the power electrode hole 46, and the GND electrode hole 47 are electrically connected to the output connector terminal 51, the power connector terminal 52, and the GND connector terminal 53 in the case 50 by soldering.

  Next, the cover 57 is formed of a resin using a light-transmitting material so that the mounting support 58 having the insertion recess 60 is provided downward.

  Next, as shown in FIG. 10, the cover 57 is put on the opening 50 a of the case 50, and the laser 62 is applied to the insertion recess 60 in the mounting column 58 of the cover 57 and the columnar part 56 in the mounting column 54 of the case 50. By irradiating, the circuit board 44 is sandwiched between the support portion 55 in the mounting column 54 of the case 50 and the support portion 59 in the mounting column 58 of the cover 57. At this time, the laser 62 passes through the cover 57 made of a light-transmitting material, melts the surface of the case 50 made of the light-absorbing material, and joins the light-transmitting material and the light-absorbing material. It is.

  Finally, by irradiating the connection portion between the case 50 and the cover 57 with the laser 62, the boundary surface with the cover 57 in the case 50 made of a light absorbing material is melted and bonded to the cover 57. Accordingly, the case 50 is closed by the cover 57.

  As described above, in one embodiment of the present invention, the cover 57 is made of a light-transmitting material and the case 50 is made of a light-absorbing material. By melting the surface portion of the absorptive material, it can be adhered to the light-transmitting material, whereby the circuit board is fixed to the mounting column of the case by heat caulking as in the past, and the cover is further attached to the case. Since it is not necessary to attach with screws, the number of parts of the angular velocity sensor and the number of assembly steps can be reduced.

  In one embodiment of the present invention, the insertion recess 60 is provided in the mounting column 58 of the cover 57, and the columnar part 56 is provided in the mounting column 54 of the case 50. Since the circuit board 44 is sandwiched between the circuit board 44 and the mounting strut 54 of the case 50 and the mounting strut 58 of the cover 57, the circuit board 44 can be securely clamped and the case 50 and the cover 57 can be It has the effect that it can be firmly fixed.

  Next, the operation of the angular velocity sensor according to the embodiment of the present invention constructed and assembled as described above will be described.

  First, a voltage input via the power connector terminal 52 and the circuit board 44 is converted into an AC voltage by the processing circuit 48 by an external power source (not shown), and the AC voltage is converted into an oscillator in the element unit 21. The first drive electrode 31a and the second drive electrode 31b are applied. When the drive electrodes 31a and 31b are grounded via the GND electrode hole 47 and the GND connector terminal 53 in the circuit board 44, the vibrator 22 bends and vibrates. In this state, when the element unit 21 rotates at the angular velocity ω around the longitudinal central axis of the vibrator 22, a Coriolis force of F = 2 mV × ω is generated in the vibrator 22. Due to this Coriolis force, an output signal composed of electric charges generated at the detection electrode 32 is converted into an output voltage by the processing circuit 48 in the circuit board 44 through the output electrode 38, and the counterpart computer (see FIG. The angular velocity is detected by inputting to (not shown).

  In the above-described embodiment of the present invention, one cover 57 is made of a light-transmitting material and the other case 50 is made of a light-absorbing material. Even when one cover 57 is made of a light-absorbing material and the other case 50 is made of a light-transmitting material, the same effects as those of the embodiment of the present invention can be obtained.

  In the embodiment of the present invention described above, the support portion 59 is provided at the tip of the attachment column 58 formed on the one cover 57, the insertion recess 60 is provided on the inner side, and the attachment is formed on the other case 50. A support portion 55 is provided on the support column 54, and a cylindrical portion 56 is provided at the tip, and the cylindrical portion 56 is inserted into the insertion recess 60, whereby the circuit board 44 is supported by the support portion 59 of the cover 57 and the case 50. As shown in FIG. 11, the support portion 65 is provided at the tip of the mounting column 64 formed on the other case 63, and the insertion recess 66 is provided on the inner side. A support portion 69 is provided on a mounting column 68 formed on one cover 67, a columnar portion 70 is provided at the tip, and the columnar portion 70 is connected to the case 6 described above. The circuit board 44 is sandwiched between the support portion 65 provided on the mounting post 64 of the case 62 and the support portion 69 provided on the mounting post 68 of the cover 67, that is, Even when it is configured to be sandwiched, the same effects as those of the embodiment of the present invention can be obtained.

  In the embodiment of the present invention, the support portion 59 is provided at the tip of the mounting column 58 formed on one cover 57, the insertion recess 60 is provided on the inside, and the other case 50 is formed. A support portion 55 is provided on the mounting column 54, and a cylindrical portion 56 is provided at the tip, and the cylindrical portion 56 is inserted into the insertion recess 60, whereby the circuit board 44 is attached to the support portion 59 of the cover 57 and the case 50. As shown in FIG. 12, the support portion 71 is provided on the mounting column 68 formed on one cover 67, the columnar portion 70 is provided, and the other portion is sandwiched between the support portions 55. A support portion 74 is provided on a mounting column 54 formed on the case 50, a columnar portion 56 is provided, and a tip 75 of the columnar portion 56 and the cover are provided. The support portion 74 provided on the attachment column 54 of the case 50 and the support portion 71 provided on the attachment column 68 of the cover 67 are brought into contact with each other. Even when the circuit board 44 is sandwiched, that is, when sandwiched, the same effects as those of the embodiment of the present invention can be obtained. In this case, the tip 75 of the columnar portion 56 provided on the mounting column 54 of the case 50 and the tip 72 of the columnar portion 70 provided on the mounting column 68 of the cover 67 are in contact with each other. It may be fixed by laser welding, and according to such a configuration, it is possible to obtain an effect that the case 50 and the cover 67 can be firmly fixed with a simple configuration.

  The angular velocity sensor according to the present invention has an effect that it can provide an angular velocity sensor that can reduce the number of parts and the number of assembly steps, and is particularly used for detecting the behavior of a vehicle body in a vehicle body control device of an automobile. It is useful as an angular velocity sensor.

1 is an exploded perspective view of an angular velocity sensor according to an embodiment of the present invention. Side sectional view of the same angular velocity sensor The perspective view which shows the state which removed the cover from the angular velocity sensor The exploded perspective view of the element part in the same angular velocity sensor Perspective view of transducer in same angular velocity sensor Side sectional view of the first arm portion in the vibrator of the angular velocity sensor Perspective view of transducer case in same angular velocity sensor The perspective view which looked at the vibrator case in the same angular velocity sensor from the back side Assembly process diagram of angular velocity sensor according to one embodiment of the present invention Sectional drawing which shows the state which irradiates a laser to the same angular velocity sensor Side sectional view which shows the other example of the angular velocity sensor in one embodiment of this invention Side sectional view which shows the other example of the angular velocity sensor in one embodiment of this invention An exploded perspective view of a conventional angular velocity sensor An exploded perspective view of a conventional angular velocity sensor

Explanation of symbols

22 vibrator 44 circuit board 48 processing circuit 49 mounting hole 50, 63 case 50a opening 54, 58, 64, 68 mounting post 55, 59, 65, 69 support part 56, 70 cylindrical part 57, 67 cover 60, 66 Insertion recess 72,75 Tip

Claims (3)

A vibrator, a processing circuit for driving the vibrator to vibrate, and converting electric charges generated by the Coriolis force from the vibrator into an output signal, and at least two mounting holes provided with the processing circuit on the upper surface or the lower surface A circuit board provided with a mounting board, and the vibrator and the circuit board are housed inside, and a mounting column inserted into the mounting hole of the circuit board and having a support portion is provided upward from the inner bottom surface, and the opening. And a cover provided with an attachment column having a support portion at a position facing the attachment column of the case and closing the opening of the case, and the support unit and the cover in the attachment column of the case The circuit board is sandwiched between the support portions of the mounting support posts, and either the case or the cover is made of a light transmissive material. Angular velocity sensor constitute the other light absorbing material. An insertion recess is provided in one of the case mounting column and the cover mounting column, and a columnar part is provided in the other, and the columnar part is inserted into the insertion recess to sandwich the circuit board. The angular velocity sensor according to 1. 2. The angular velocity sensor according to claim 1, wherein the circuit board is clamped by bringing the tip of the case mounting column into contact with the tip of the cover mounting column.

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