JP2015058780A - On-vehicle device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inhibit creaky sounds from being produced between a circuit board and a contact part at a device in which the circuit board is sandwiched by the contact part of a case.SOLUTION: A case 2, in which a circuit board 3 is stored, is formed by connecting an upper case 5 and a lower case 6 with an engagement structure. A rib 13 which contacts with an upper surface of the circuit board 3 is integrally provided at the upper case 5. Elastic support parts 14, each of which cooperates with the rib 13 to sandwich the circuit board 3 in a vertical direction and support the circuit board 3 in the state, are integrally provided at the lower case 6. A protruding part 16 which contacts with a lower surface of the circuit board 3 is provided on an upper surface of each elastic support part 14. Further, an auxiliary contact part 17 which is located near (at the inner side of) the protruding part 16 and has a protruding shape is integrally provided on the upper surface of each elastic support part 14. The auxiliary contact part 17 is separated from the lower surface of the circuit board 3 at normal time and contacts with the lower surface of the circuit board 3 when the case 2 deflects.

Description

  The present invention relates to a vehicle-mounted device configured by housing a circuit board in a case, such as an ETC vehicle-mounted device or a DSRC vehicle-mounted device.

  As an in-vehicle device mounted on a vehicle, for example, an ETC in-vehicle device, a DSRC in-vehicle device, and the like are known, and in these in-vehicle devices, in general, a circuit in which an electronic component is mounted in a case made of synthetic resin, for example. A substrate is provided. In this case, for example, Patent Document 1 discloses a structure in which an upper case and a lower case constituting a case are connected by engagement, and a rib (contact portion) formed integrally with the upper case and the lower case. Discloses a configuration in which the circuit board is held between the upper and lower sides. According to this, the number of parts such as screws can be reduced, and assembling can be simplified.

JP 2012-228903 A

  By the way, it is considered to share a case with respect to a plurality of types of in-vehicle devices such as the above-described ETC in-vehicle device and DSRC in-vehicle device. However, since the DSRC in-vehicle device has more circuit components (number of parts and the like) than the ETC in-vehicle device, for example, the ETC in-vehicle device uses a four-layer multilayer board, whereas the DSRC in-vehicle device uses 6 layers. There is a situation in which a multi-layer substrate is used. Therefore, in order to share the case with respect to the difference in the number of layers of the circuit board and the thickness dimension, for example, the rib on the lower case side among the ribs sandwiching the circuit board is elastically deformed following the thickness of the circuit board. It can be considered to have a shape.

  However, in the in-vehicle device configured to share the above-described case, the sliding (friction) between the circuit board and the rib portion of the case holding the circuit board at the time of attachment to the vehicle or use, There was a problem that squeak noise was generated. Such a squeak noise is mainly caused by a load applied to the center of the case when the case is pressed down when mounting the in-vehicle device in the car with double-sided tape, etc. Occurs when

  This squeak noise is called stick-slip noise. As the case is flexed and deformed from the normal state, the transition between the rib of the case and the circuit board changes from the stick state to the slip state, at which time energy is released. Sound is generated when the released energy is large. As described below, as the minimum and maximum range of circuit board thickness increases, it becomes more difficult to reduce the release energy. In the case of holding multiple types of circuit boards with different thicknesses in common, the holding power There is a possibility that the problem of squeak noise cannot be solved even if the adjustment (decrease) is made.

  That is, FIG. 5 illustrates a case where a squeak noise is generated with respect to the relationship between the thickness dimension of the circuit board and the holding force (clamping force) of the circuit board by the case. FIG. 5A shows a case where only one type of circuit board (for example, a four-layer board) is held, and FIG. 5B shows a case where two types of circuit boards (for example, a four-layer board and a six-layer board) are held. Is illustrated. Here, it is assumed that the holding force necessary for holding the circuit board is equal to or greater than the reference value F1, and if the release energy exceeds the threshold value F2, a squeak noise is generated. There is some variation in the thickness dimension of the circuit board. The larger the thickness dimension within the variation, the greater the holding power of the circuit board, and the greater the holding power of the board, the greater the release energy.

  As shown in FIG. 5A, in the case of holding one type of circuit board (four-layer board), the variation in the thickness dimension of the circuit board is a relatively narrow range from dimension T1 to T2. Now, assuming that the holding force P of the circuit board is a value indicated by a solid line, the release energy R is indicated by a solid line, and the release energy exceeds the threshold F2 on the side where the thickness dimension is large, and a squeak noise is generated. May occur. Therefore, when the holding force of the circuit board is reduced to P ′ indicated by a broken line in the range of the reference value F1 or more, the released energy becomes R ′ indicated by the broken line, and can be suppressed to the threshold value F2 or less. That is, in the case of holding one type of circuit board, the generation of squeak noise can be suppressed with a relatively simple measure such as adjusting (decreasing) the holding force.

  On the other hand, as shown in FIG. 5B, in the case of holding two types of circuit boards (four-layer board and six-layer board), the variation in the thickness dimension of the four-layer board is in the range of dimensions T1 to T2. Thus, the variation in thickness of the thicker six-layer substrate is in the range from T3 to T4, and the overall variation is in a relatively wide range from T1 to T4. In this case, assuming that the holding force P of the circuit board is a value indicated by a solid line, the release energy R is indicated by a solid line, and the release energy exceeds the threshold value F2 in most of the portions except for the smaller thickness dimension. There is a risk of squeaking noise. However, even if the holding force of the circuit board is reduced to P ′ indicated by a broken line within the range of the reference value F1 or more, the release energy also becomes R ′ indicated by the broken line, and the release energy is the threshold value F2 on the side where the thickness dimension is large. There still remains the problem of squeaking noises.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to hold a circuit board by a contact part of a case, and a squeak noise between the circuit board and the contact part. It is in providing the vehicle-mounted apparatus which can suppress generation | occurrence | production.

  In order to achieve the above object, an in-vehicle device according to the present invention is configured to accommodate a circuit board in a case, and the case is in contact with one surface of the circuit board. A first case having a contact portion, and a second case having a second contact portion that contacts the other surface of the circuit board, the first contact portion and the second contact The circuit board is configured to be sandwiched between the contact portion, and at least one of the first case and the second case is normally separated from the surface of the circuit board, and A feature is that an auxiliary contact portion is provided to contact the circuit board when the case is flexibly deformed.

  According to this, the circuit board in the case is sandwiched and held between the first contact portion and the second contact portion provided in the case. Here, for example, when the case is bent and deformed by an external force, there is a possibility that the contact portion and the circuit board may transition from the stick state to the slip state. In addition to the contact portion being in contact, the auxiliary contact portion is in contact. As a result, the contact location (contact area) of the contact portion with the surface of the circuit board is increased, the sliding resistance is increased, and the transition to the slip state is difficult.

  Therefore, according to the present invention, the circuit board is sandwiched by the contact portion of the case, and the excellent effect that the generation of squeak noise between the circuit board and the contact portion can be suppressed. Play. In normal times (when the case is not flexed and deformed), the auxiliary contact portion is not in contact with the surface of the circuit board, so that the holding force by the contact portion with respect to the circuit board does not increase more than necessary. .

1 is a plan view of an in-vehicle device according to an embodiment of the present invention. A vertical right side view along line AA in FIG. 1 (a) and a front view along vertical line BB in FIG. 1 (b). Enlarged longitudinal front view of the main part at normal time (a) and at the time of bending deformation of the case (b) for explaining the relationship between the circuit board and the auxiliary contact part The perspective view which shows a mode that external force acts on the upper surface side (a) and lower surface side (b) of a case. It is for explaining the relationship between the thickness dimension of the circuit board and the holding force and release energy by the case. (A) holds one kind of circuit board, (b) holds two kinds of circuit boards. Figure showing when to

  Hereinafter, an embodiment in which the present invention is applied to an ETC / DSRC vehicle-mounted device as a vehicle-mounted device will be described with reference to the drawings. In the following description, for the sake of convenience, the surface of the case having the slot for the ETC / DSRC card (not shown) will be described as the front surface (the state of FIG. 1 is a plan view). The ETC / DSRC card is composed of, for example, a well-known contact type IC card.

  As shown in FIGS. 1 and 2, the in-vehicle device 1 according to the present embodiment includes a circuit board 3, a card connector 4, and the like in a case 2 made of synthetic resin, for example. As shown in FIG. 4, the case 2 has a substantially rectangular box shape that is slightly longer in the front-rear direction and thin in the height (vertical) direction, and includes an upper case 5 that is a first case, The lower case 6 which is a case is combined. The front side of the case 2 (upper case 5) is provided with a horizontally long slit-shaped card slot 7 which is located near the lower part. The front end of the case 2 is provided with a gently curved (arc-shaped) recess 2a located at the center in the left-right direction.

  As shown in FIG. 2, the circuit board 3 is disposed at a substantially middle portion in the height (up and down) direction in the case 2, and various electronic components 8 are mounted on the upper surface which is one surface thereof. Has been. Thus, the circuit board 3 includes various circuits such as a communication control circuit that controls communication with the outside, a card processing circuit that reads and writes an ETC / DSRC card, and a power supply circuit. A polymer sheet 9 made of, for example, urethane foam is disposed on the inner surface (ceiling surface) of the upper case 5 so as to be positioned between the electronic component 8.

  At this time, although not shown in detail, the case 2 is shared for the ETC in-vehicle device and the DSRC in-vehicle device, but the DSRC in-vehicle device has more circuit components (such as the number of parts) than the ETC in-vehicle device. As the circuit board 3, for example, a 4-layer multilayer board is used in an ETC in-vehicle apparatus, whereas a 6-layer multilayer board is used in a DSRC in-vehicle apparatus, and the circuit board 3 for the DSRC in-vehicle apparatus is an ETC in-vehicle apparatus. The thickness is slightly larger than that for machine use. The circuit board 3 is sandwiched between the upper case 5 and the lower case 6 and disposed in the case 2. The detailed structure of the case 2 including the support structure for the circuit board 3 will be described later.

  The card connector 4 is provided on the lower surface side (between the lower case 6) that is the other surface of the circuit board 3. Although not shown in detail, the card connector 4 includes a lock mechanism for locking the ETC / DSRC card inserted from the card insertion / removal port 7 in the reading position, a contact electrically connected to the ETC / DSRC card in the reading position, When the eject button 18 (see FIG. 4) is operated, a card ejection mechanism for ejecting the ETC / DSRC card is provided. As shown in FIG. 1, a connector (not shown) for connection with a power source or an antenna device is provided on the rear surface of the case 2 so that a cable 10 is connected thereto.

  Now, the case 2 will be described in detail with reference to FIG. The upper case 5 is formed in a thin, substantially rectangular box shape having an open bottom surface, and constitutes a ceiling wall, left and right side walls, a front wall, and a rear wall of the case 2. The card slot 7 is formed in the front wall portion of the upper case 5. Although not shown, a connector opening is formed in the rear wall portion of the upper case 5. On the other hand, the lower case 6 constitutes the bottom wall of the case 2 and integrally has side walls that rise at a slight height on the left and right sides of the bottom wall. The lower case 6, the left and right side wall portions, and the left and right side wall portions of the upper case 5 are partially wrapped in the vertical direction so that the upper case 5 side is on the outside.

  At this time, as shown only in part in FIG. 2 (b), the side wall of the upper case 5 includes, for example, two places before and after the left side wall and one place behind the right side wall. The engaging claw 11 is formed at a location so as to face inward. On the other hand, the lower case 6 has engagement recesses 12 formed at positions corresponding to the three engagement claws 11 on the outer surface side of the left and right side wall portions. Thus, the upper case 5 and the lower case 6 are connected without using another part such as a screw by engaging the engaging claws 11 with the engaging recesses 12 at three positions on the left and right wall sides. It is like that.

  Further, as shown in a part of FIG. 2 (b), the upper case 5 is integrally formed with ribs 13 at a total of four locations in the front and rear portions of the left and right sides. These ribs 13 are formed in a thin plate shape in the front and rear, and are provided so as to extend downward at a portion extending from the ceiling surface of the upper case 5 to the inner surface of the side wall. The front end surfaces (lower end surfaces) of these ribs 13 are provided so as to extend horizontally, and abut on the upper surface of the circuit board 3 (a total of four locations near the left and right sides). Therefore, the tip surface of the rib 13 functions as a first contact portion.

  On the other hand, the left and right side wall portions of the lower case 6 are supported so as to sandwich the circuit board 3 from above and below in cooperation with the ribs 13, as shown in part in FIGS. 2 (a) and 2 (b). For this purpose, an elastic support portion 14 is integrally provided. The elastic support portions 14 are provided at a total of four locations on the front and rear portions of the left and right side wall portions of the lower case 6. As shown in FIG. 2A, the elastic support portion 14 includes a base portion 14a extending upward from the upper surface of the side wall portion of the lower case 6, and a front-rear direction (right side in FIG. 2A) from the upper end of the base portion 14a. And a movable portion 14b that is elongated.

  At this time, a groove (cut) 15 is formed on the lower surface side (between the upper surface of the side wall portion) of the movable portion 14b to allow deformation (elastic deformation) downward of the movable portion 14b. Further, two projecting portions 16 are integrally provided on the upper surface of the movable portion 14b at positions closer to the outer side of the front end (rear end) and the intermediate portion. These protrusions 16 function as second contact portions that contact the lower surface of the circuit board 3. Thus, the circuit board 3 is placed (set) on the respective elastic support portions 14 (projections 16) of the lower case 6 in a positioned state, and the upper case 5 is connected to the lower case 6 in this state. The Thereby, the circuit board 3 is clamped between the rib 13 and the elastic support part 14 (projection part 16) in the left and right side parts.

  In this embodiment, as shown in FIGS. 2B and 3, each elastic support portion 14 is located in the vicinity (inner side) of the protruding portion 16 and has a protruding auxiliary contact portion. 17 is provided integrally. As shown in FIG. 3A, the auxiliary contact portion 17 is formed slightly lower than the upper end of the projection portion 16, and in a normal state, it is a slight distance t ( For example, about 0.1 mm). On the other hand, as will be described in the following description of the operation, for example, when the case 2 is deformed by bending due to an external force, it contacts the lower surface of the circuit board 3 together with the protrusion 16 as shown in FIG. It has become.

  Next, the operation of the above configuration will be described. The in-vehicle device 1 configured as described above is attached to a vehicle interior of the vehicle, for example, a lower portion of an instrument panel. At this time, when the case 2 of the vehicle-mounted device 1 is attached to the vehicle interior with a double-sided tape or the like, the case 2 is pressed down, for example, when the occupant's knee hits the case 2, etc. When a load (external forces F1 and F2 shown in FIGS. 4A and 4B) is applied to the case 2 and the case 2 is bent and deformed, there is a possibility that a squeak noise called a stick-slip sound may be generated.

  This squeak noise is called stick-slip noise, and the rib 13 of the upper case 5 shifts from the stick state to the slip state with respect to the upper surface of the circuit board 3 as the case 2 bends and deforms from the normal state. When the elastic support part 14 (projection part 16) of the lower case 6 moves from the stick state to the slip state and slides relative to the lower surface of the circuit board 3, a sound is generated when the released energy is large. To do. In this case, in the above structure, a large load is applied from the circuit board 3 to the lower case 6 due to the presence of the polymer sheet 9 and the like, and the degree of contribution of squeak noise is large on the lower case 6 side (the lower surface side of the circuit board 3). Become.

  In particular, as in the vehicle-mounted device 1 of this embodiment, the case 2 is shared with respect to a plurality of types of circuit boards 3 having different thicknesses, that is, the minimum and maximum ranges of the thickness dimension of the circuit board 3 to be held are increased. However, as described in the section “Problems to be Solved by the Invention”, the problem of squeak noise may not be solved even if the holding force (holding force) of the circuit board 3 by the case 2 is adjusted (decreased). (See FIG. 5B).

  However, in the in-vehicle device 1 of the present embodiment, the elastic support portion 14 of the lower case 6 is provided with an auxiliary contact portion 17 in addition to the projection portion 16. As a result, normally, as shown in FIG. 3A, only the protrusion 16 is in contact with the lower surface of the circuit board 3, but when the case 2 is bent and deformed by the external forces F1 and F2. As shown in FIG. 3 (b), the auxiliary contact portion 17 comes into contact with the lower surface of the circuit board 3 in addition to the contact with the projection 16.

  As a result, the contact portions (contact areas) of the contact portions 16 and 17 with respect to the surface of the circuit board 3 are increased, and the sliding resistance is increased, so that it is difficult to make a transition from the stick state to the slip state. Is less likely to occur. In the normal state (when the case 2 is not flexed and deformed), the auxiliary contact portion 17 is separated from the lower surface of the circuit board 3, so that the holding force with respect to the circuit board 3 may become larger than necessary. Absent.

  Thus, according to the in-vehicle device 1 of the present embodiment, the circuit board 3 is sandwiched between the rib 13 and the elastic support portion 14 of the case 2, and the protrusion is formed on the elastic support portion 14 of the lower case 6. Since the auxiliary contact portion 17 is provided in the vicinity of the portion 16 to contact the circuit board 3 when the case 2 is bent and deformed, a squeak noise between the circuit board 3 and the elastic support portion 14 is provided. The outstanding effect that generation | occurrence | production can be suppressed can be acquired.

  In the above-described embodiment, the auxiliary contact portion 17 is provided in the vicinity of the projection portion 16. However, the auxiliary contact portion is continuous with the first contact portion or the second contact portion. It can also provide in such a taper shape. Even in this case, only the first contact portion (or the second contact portion) normally contacts the surface of the circuit board, and the first contact portion (or the second contact portion) is deformed as the case is deformed. The contact portion) and the auxiliary contact portion come into contact with the circuit board over a wide area, and the same operation and effect as in the case of the protrusion can be obtained.

  In the above-described embodiment, the auxiliary contact portion 17 is provided on the lower case 6 side. However, the auxiliary contact portion may be provided on the upper case side, and may be provided on both the first and second cases. Anyway. In addition, the shape of the case, the structure such as the engagement structure, the position and the number of the contact portions, and the like can be variously modified. The present invention is not limited to the ETC in-vehicle device and the DSRC in-vehicle device. The present invention can be implemented with appropriate modifications within a range that does not depart from the gist, such as being applicable to all devices.

  In the drawings, 1 is an in-vehicle device, 2 is a case, 3 is a circuit board, 5 is an upper case (first case), 6 is a lower case (second case), 11 is an engaging claw, 12 is an engaging recess, Reference numeral 13 denotes a rib (first contact portion), 14 denotes an elastic support portion, 16 denotes a projection portion (second contact portion), and 17 denotes an auxiliary contact portion.

Claims (4)

A vehicle-mounted device configured by housing a circuit board in a case,
The case has a first case having a first contact portion that contacts one surface of the circuit board, and a second case having a second contact portion that contacts the other surface of the circuit board. A case, and configured to sandwich the circuit board between the first contact portion and the second contact portion,
Either or both of the first case and the second case are usually provided with an auxiliary contact portion that is separated from the surface of the circuit board and contacts the circuit board when the case is bent and deformed. An in-vehicle device characterized in that At least one of the first contact portion and the second contact portion is configured to be elastically deformable,
The in-vehicle device according to claim 1, wherein the auxiliary contact portion is provided in the vicinity of the elastically deformable contact portion.   The in-vehicle device according to claim 1, wherein the auxiliary contact portion is provided in a convex shape in the vicinity of the contact portion.   The in-vehicle device according to claim 1, wherein the auxiliary contact portion is provided in a tapered shape so as to be continuous with the contact portion.

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