JPH11281407A - Sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve workability of mounting a sensor in a sensor case while keeping reliable mounting, and to miniaturize a sensor case. SOLUTION: Both a lower case and an upper case 24 are die-cast molded, wherein the upper case 24 is provided with leg parts 37 protruded from plural parts of the inside surface of the upper case 24 and having circuit board clamping surfaces 36 to press a circuit board against circuit board receiving parts of the lower case to clamp it, mounting screw insertion holes 39 punched in the leg parts 37 and notch parts 40 each formed on a part of the circuit board clamping surface 36 not to come in contact with a circuit pattern.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sensor in which, for example, a satellite sensor for an airbag is housed in a sensor case. The present invention relates to a sensor having a configuration that enhances performance and allows the sensor case to be downsized.

[0002]

2. Description of the Related Art As a conventional example of a sensor (satellite sensor) structure used for operating an airbag device installed in an automobile when a side impact of the automobile is generated,
For example, there is one as shown in FIG.

[0003] Reference numeral 1 denotes a sensor case having a mounting hole 3 through which a mounting screw 2 to be fixed to a vehicle body (not shown) is inserted. A storage unit 4 is provided, and the sensor storage unit 4 is provided.
A circuit board mounting surface 6 formed with mounting screw holes 5 is formed integrally with the sensor case 1 at a pair of diagonal positions on the inner bottom surface of the sensor case 1. The receiving surface 8 of the rectangular circuit board 7 is formed integrally with the sensor case 1 at the diagonal positions of the other pairs.

The circuit board 7 is set to have a slightly smaller size than the opening (insertion port) of the sensor accommodating section 4, and the upper surface of the circuit board 7 detects acceleration such as collision. An acceleration sensor main body 8, a CPU 9 for calculating a signal from the acceleration sensor main body 8, and judging whether or not an airbag (not shown) needs to be deployed;
Further, respective screw insertion holes 11 corresponding to the mounting screw holes 5 are formed at a pair of diagonal positions of the circuit board 7. Reference numeral 12 denotes a lead wire connected to the circuit board 7 and drawn out of the sensor case 1.

[0005] Reference numeral 13 denotes a protective cover for protecting the circuit board 7 stored in the sensor storage unit 4 in the sensor storage unit 4. A press contact piece 14 having screw insertion holes 14A, 14A formed in a pair of diagonal positions corresponding to the mounting screw holes 5 is bent and formed at a pair of diagonal positions. At the diagonal positions, respective pressing edges 15 which are bent at right angles toward the inner bottom surface of the sensor housing 4 and press the circuit board 7 at the ends thereof are formed. Reference numeral 16 denotes a mounting screw for screwing the protective cover 13 and the circuit board 7 into the sensor case 1.

The sensor (satellite sensor) assembled by the above-mentioned respective components has a circuit board 7 inserted into the sensor housing 4 of the sensor case 1, and then the circuit board 7
, The protective cover 13 is inserted into the sensor housing 4 from above, and then the mounting screws 16 are screwed into the screw insertion holes 14A, 11A.
Through which the protective cover 13 is screwed into the mounting screw hole 5.
Then, the circuit board 7 is fixed in the sensor housing section 4 of the sensor case 1, and then the space defined by the sensor housing section 4 and the protective cover 13 is filled with a molding material, and the circuit board 7 is embedded in the molding material. Then, the sensor is configured so that the circuit board 7 is protected.

[0007]

However, in the conventional sensor having such a structure, the protective cover 13 used for holding and fixing the circuit board 7 housed in the sensor case 1 is provided with a screw 16. Are formed by pressing the upper surface corners of the circuit board 7 by screwing, and the circuit board 7 is sandwiched by the pressing pieces 14. 7 on the peripheral circuit 10
In forming this pattern, the pattern must be formed so as to avoid the contact surface of the pressing piece 14. That is, since the contact surface with the pressing piece 14 must be formed at the corner of the circuit board 7 avoiding the peripheral circuit 10, the area of the circuit board 7 becomes large, and accordingly, the overall shape of the sensor is reduced. There was a problem that the size was increased.

In the conventional sensor, the circuit board 7 on which the acceleration sensor main body 8 is mounted has only four supporting points in the case at the four corners of the circuit board 7.
The center portion is in a bridge state, so that the sensor receives vibration of the vehicle body or the like, and resonance occurs in the circuit board 7, which makes it impossible to detect an accurate acceleration signal. There was also.

Further, when assembling a conventional sensor, the circuit board 7 to which the lead wires 12 are connected is housed in the sensor case 1 and then the protective cover 13 is put on the circuit board 7. At this time, the circuit board 7 to be stored in the sensor case 1 is moved to the predetermined position in the sensor case 1 because the circuit board 7 is moved by the elastic restoring force of the lead wire 12. Work is difficult. Further, when the pressing force by the finger of the assembling operator is applied to the circuit board 7 in order to forcibly perform the positioning, the difference in the pressing force due to the individual difference of the assembling operator or the circuit board 7 is erroneously unnecessarily applied. There is also a problem that the circuit board 7 and the electronic components are damaged by applying a pressing force.

SUMMARY OF THE INVENTION The present invention has been made in view of such a conventional problem, and it has been made possible to extend the effective wiring area of a circuit board having a predetermined shape (area), thereby increasing the size of the circuit board. It is a first object of the present invention to suppress the increase in the size of a sensor in which a circuit board is mounted.

Further, according to the present invention, when assembling a circuit board in a sensor case, the ease and reliability of positioning of the circuit board in the case is improved, thereby improving the assembling workability of the sensor. It has two purposes.

Further, according to the present invention, the circuit board to be assembled in the case is securely sandwiched and fixed between the case and the lid of the case, so that resonance does not occur in the circuit board provided in the case. It is a third object of the present invention to provide a case configuration capable of avoiding deformation due to an excessive pressing force applied to the circuit board by an operator at the time of assembling the circuit board in the case.

[0013]

In order to achieve the first object, according to the first aspect of the present invention, a circuit board on which a sensor body and electronic components are mounted is housed in a lower case, In a sensor configured to position a circuit board housed in the lower case by an upper case attached to the lower case, both the lower case and the upper case are die-cast, and the upper case has a plurality of inner surface portions. A leg having a circuit board pressing surface for pressing and holding the circuit board to the circuit board receiving portion of the lower case, a mounting screw insertion hole drilled in the leg, A sensor formed on a part of the circuit board holding surface and provided with a cutout formed to avoid contact with a circuit pattern provided on the circuit board. It is characterized by a door.

According to another aspect of the present invention, there is provided a semiconductor device comprising:
Then, in addition to the above claim 1, a first through-hole and a second through-hole are formed in the circuit board, and the leg is protruded from an inner surface of the upper case. A first boss portion and a second boss portion protruded in the same direction as the first boss portion and inserted into the first through hole and the second through hole formed in the circuit board. It is characterized by being.

According to a third aspect of the present invention, in addition to the third aspect, the circuit board is provided on an outer peripheral surface of one of the first boss portion and the second boss portion. The sensor is characterized in that it is a sensor having a circuit board contact step which regulates the deflection of the circuit board.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the embodiments shown in FIGS.

Reference numeral 21 denotes a sensor for operating an airbag having an acceleration sensor body 22 therein. The sensor 21 is attached to a die-cast lower case 23 and an opening of the lower case 23. Inside a case composed of a similar die-cast upper case 24,
A circuit board 26 on which the acceleration sensor main body 22, the electronic components 25 and the like are mounted is provided. Further, on the upper surface of the circuit board 26, a circuit pattern 27 related to the acceleration sensor main body 22, the electronic component 25 and the like is formed.
The circuit board 26 and the electronic components 25 and the like housed inside the case are waterproof and protected by filling with a molding material 28 made of soft urethane, soft silicon, or the like.

Next, the structure of the die-cast lower case 23 and the upper case 24 will be described. First, the structure of the lower case 23 will be described with reference to FIG.

As shown in FIG. 2, the lower case 23 has a rectangular circuit board housing portion 29 for housing the circuit board 26. The lower case 23 has three corners on the inner bottom surface of the circuit board housing portion 29, respectively. A board mounting screw hole 30 is formed, and an upper case positioning protrusion 31 is formed at a position close to the remaining corner. Further, the upper case positioning hole 3 is located substantially symmetrically with the upper case positioning protrusion 31.
2 are formed, and a pair of circuit board receiving portions 33 are formed to face each other at the center of the wall surface of the circuit board storage portion 29. Reference numeral 34 denotes a mounting portion to a vehicle body or the like, and a mounting hole 35 is formed in the mounting portion 34.

Next, as shown in FIG. 3, the upper case 24 has a flat plate portion 38 which is formed in a substantially rectangular plane and can be fitted into a circuit board storage portion 29 formed in the lower case 23. The leg portions 37 each having a circuit board pressing surface 36 are integrally formed at three corners of the flat plate portion 38. Further, these leg portions 37 have mounting screw insertion holes 3 corresponding to the respective substrate mounting screw holes 30 provided in the lower case 23.
9 are drilled.

The circuit board pressing surface 36 of two of the three legs 37 is formed on the circuit board 26 as shown in FIGS. 3 (c) and 3 (e). A notch 40 is formed to avoid contact with the circuit pattern 27. The cutouts 40 may be provided in all the legs 37 as needed. In addition, these notches 40
Since the upper case 24 is made of die-cast and the thickness of each leg 37 can be increased, the notch 40 can be easily formed.

The leg 3 of the upper case 24
A first boss 41 is formed in the vicinity of the corner having no boss 7 in the same direction as the direction in which the leg 37 protrudes. A circuit board contact step 42 at the same level as the circuit board holding surface 36 formed in the section 37 is formed. Further, the first boss 4
A second boss 43 is formed at a position substantially symmetrical with respect to 1. Reference numeral 44 denotes a notch portion for drawing out an electric wire formed in the flat plate portion 38 of the upper case 24.
The grommet 46 through which the lead wire 45 is inserted is engaged and held (see FIG. 1). The snap-in terminal 47 attached to the end of the lead wire 45 is connected to a circuit on the circuit board 26.

Next, the configuration of the circuit board 26 on which the acceleration sensor main body 22 and the electronic components 25 are mounted is shown in FIG.
In the circuit board 26, three mounting screw insertion holes 48 corresponding to the board mounting screw holes 30 provided in the lower case 23 and a first mounting hole 48 provided in the upper case 24 are provided. Boss part 41 and second boss part 43
The first through hole 49 and the second through hole 50 through which
And a terminal 4 attached to the end of the lead wire 45.
A connection hole 51 into which the wire 7 is inserted and connected is formed. Reference numeral 52 denotes a molding material injection port formed in the circuit board 26 and the upper case 24.

The components of the sensor have been described above. Next, the assembly procedure and operation of the sensor will be described.
A terminal 47 attached to a tip end of a lead wire 45 that previously inserts and holds a grommet 46 in a connection hole 51 provided in a circuit board 26 on which the acceleration sensor body 22 and the electronic component 25 are mounted. Insert the circuit board 2
6 and the lead wire 45 are connected.

Next, each mounting screw insertion hole 39 provided in the upper case 24 is matched with each mounting screw insertion hole 48 provided in a corner of the circuit board 26 so that the circuit board 26 The upper case 24 is placed over the upper case 24. At this time, the first boss 41 and the second boss 43 provided on the upper case 24 are connected to the circuit board 26.
The first through hole 49 and the second through hole 5 provided in the
After the upper case 24 and the circuit board 26 are positioned in the planar direction by penetrating into the inside of the grommet 46, the peripheral groove 4 formed on the peripheral edge of the grommet 46 through which the lead wire 45 is inserted.
The lead wire 45 is stably held in the upper case 24 by fitting the edge of the wire drawing cutout 44 provided in the upper case 24 into 6A. At this time, the tension of the lead wire 45 acts to cause the circuit board 26 and the upper case 24 to move between the first boss 41 and the second boss 43 and the first through hole 4.
9 and the second through-hole 50 are engaged and held.

Next, the respective mounting screw insertion holes 48 provided in the circuit board 26 and the respective mounting screw insertion holes 39 provided in the upper case 24 are provided in the board mounting screw holes provided in the lower case 23. The circuit board 26 and the upper case 24 are fitted into the circuit board storage portion 29 of the lower case 23 so as to coincide with 30.
At this time, the first boss 41 is engaged with the positioning projection 31 provided on the lower case 23, and the second boss 43 is engaged with the positioning hole 32 provided on the lower case 23. The circuit board 26 and the upper case 24 are positioned in the lower case 23.

Next, mounting screws 53 are screwed into the board mounting screw holes 30 of the lower case 23 from above the upper case 24 through the mounting screw insertion holes 39 and 48, so that the upper case 24, the circuit board 26 and Lower case 23
Are joined together. After a while, upper case 2
4 and the mold material injection port 52 provided in the circuit board 26, the mold material 28 such as soft urethane or silicone resin is injected to the mold line (L) to enhance the waterproof property, and the assembly of the sensor is completed. I do.

In the sensor thus constructed, the first boss 41 and the second boss 43 provided on the upper case 24 are provided on the circuit board 26 at the time of assembly. Since the first through hole 49 and the second through hole 50 are engaged with the positioning projections 31 and the positioning holes 32 provided on the lower case 23, the lower case during the assembly process of the sensor is formed. 2
3. The positioning of the upper case 24 and the circuit board 26 can be ensured, thereby significantly improving the workability of assembling the sensor.

The lower surface of the circuit board 26 after assembly is provided with three corner seating surfaces 30 provided in the lower case 23.
A is supported by the circuit board receiving portion 33 at the center, and the upper surface of the circuit board 26 has a circuit board holding surface 36 and a first boss 41 provided at three corners of the upper case 24. Circuit board contact step 42 formed around
, The three corners of the circuit board 26 are sandwiched between the lower case 23 and the upper case 24, and the corners of the upper surface of the circuit board 26 except for the three corners are formed by the circuit board contact step 42. Since the lower case 23 is pressed,
Circuit board 2 sandwiched between the upper case 24
6, the sensor does not resonate even when the sensor receives vibration of the vehicle or the like, thereby preventing a malfunction of the sensor.

Further, since a notch 40 for avoiding contact with the upper surface of the circuit board is provided in a part of the circuit board pressing surface 36 provided on the lower surface of each leg 37 of the upper case 24,
In the circuit board 26, wiring and the like can be provided up to the portion corresponding to the cutout portion 40, whereby the size of the circuit board 26 can be reduced and the density can be increased by effectively utilizing the surface of the circuit board, and the sensor can be downsized as a whole. Can be achieved.

When assembling the circuit board 26 into the lower case 23, the circuit board 26 can be incorporated into the lower case 23 together with the upper case 24. In particular, without touching the circuit board 26, the circuit board 26 and the upper case Since the circuit board 24 can be housed in the circuit board housing portion 29 of the lower case 23, it is possible to prevent an accident such as damage to the circuit board 26 when the circuit board 26 is assembled in the case.

[0032]

As described above, according to the sensor of the present invention,
The layout efficiency of the circuit pattern with respect to the board surface of the circuit board can be improved, thereby suppressing the circuit board from increasing in size and preventing the sensor from increasing in size. In the present invention, particularly, the configuration of the upper case enhances the ease and reliability of positioning the circuit board during the assembly work of the sensor, thereby improving the assembly workability of the sensor. Further, in the present invention, protection and deformation of the circuit board at the time of assembling the sensor can be avoided, and furthermore, the circuit board after the assembly of the sensor does not cause resonance or the like, thereby stably fixing the circuit board in the case. It has the function and effect that it can be secured.

[Brief description of the drawings]

FIG. 1 is an explanatory sectional view showing an embodiment of a sensor according to the present invention.

FIGS. 2A and 2B show a lower case which is a sensor constituent member of the present invention, wherein FIG. 2A is a front view thereof, FIG.
(C) is a plan view, and (d) is a cross-sectional view taken along line BB.

3A and 3B show an upper case which is a sensor constituent member of the present invention, wherein FIG. 3A is a front view thereof, FIG. 3B is a plan view, FIGS. 3C and 3D are right and left side views, and FIG. ) Is its bottom view.

4A and 4B show a circuit board which is a sensor constituent member of the present invention, wherein FIG. 4A is a plan view and FIG.

FIG. 5 is a sectional view showing a main part of the assembled sensor of the present invention.

FIG. 6 is an exploded perspective view showing constituent members of a conventional sensor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 21 ... Sensor 22 ... Acceleration sensor main body 23 ... Lower case 24 ... Upper case 25 ... Electronic component 26 ... Circuit board 27 ... Circuit pattern 28 ... Mold material 29 ... Circuit board accommodation part 30 ... Board mounting screw hole 31 ... Positioning protrusion 32 ... Positioning Hole 33 ... Circuit board receiving part 34 ... Mounting part 35 ... Mounting hole 36 ... Circuit board holding surface 37 ... Leg part 38 ... Plate part 39 ... Mounting screw insertion hole 40 ... Notch part 41 ... First boss part 42 ... Circuit board Abutment step 43 ... Second boss 44 ... Cut for drawing out electric wire 45 ... Lead wire 46 ... Grommet 47 ... Snap-in terminal 48 ... Mounting screw insertion hole 49 ... First through hole 50 ... Second through hole 51: Connection hole 52: Mold material injection port 53: Mounting screw

Claims (3)

[Claims] A sensor body (22) and an electronic component (2)
5) The circuit board (26) on which the
3) A sensor configured to position the circuit board (26) housed in the lower case (23) with the upper case (24) housed in the lower case (23) and attached to the lower case (23). Both (23) and the upper case (24) are die-cast, and the upper case (24) is protruded inward from a plurality of locations on the inner surface thereof, and the circuit board (26) is attached to the lower case (2).
A leg (37) having a circuit board pressing surface (36) for being pressed and clamped by the circuit board receiving portion (33) of 3), and a mounting screw insertion hole (39) formed in the leg (37). When,
A circuit pattern (27) formed on a part of the circuit board holding surface (36) and provided on the circuit board (26).
Notch (40) formed to avoid contact with
And a sensor comprising: 2. A first through hole (49) and a second through hole (50) are formed in the circuit board (26), and the upper case (24) is formed from an inner surface thereof. It projects in the same direction as the projecting direction of the leg portion (37), and enters into the first through hole (49) and the second through hole (50) formed in the circuit board (26). The first boss portion (4
2. The sensor according to claim 1, further comprising a first boss and a second boss. 3. A circuit board contact step for restricting the bending of the circuit board (26) on the outer peripheral surface of either the first boss (41) or the second boss (43). The sensor according to claim 2, wherein (42) is formed.