JP4956931B2 - Capacitor unit - Google Patents

Description

  The present invention relates to an emergency power source for an electronic device using a battery or the like, and more particularly to a capacitor unit used in an electronic brake system or the like that electrically brakes a vehicle.

  In recent years, the development of hybrid cars and electric cars has been rapidly progressing, and accordingly, various proposals from conventional mechanical hydraulic control to electrical hydraulic control have also been made for vehicle braking.

  Generally, a battery is used as a power source to electrically control the hydraulic pressure of the vehicle. In this case, if the power supply is cut off for some reason, the hydraulic control cannot be performed and the vehicle cannot be braked. There is a possibility.

  Therefore, proposals have been made that can cope with an emergency by mounting a large-capacity capacitor or the like as an emergency auxiliary power source in addition to the battery.

  Capacitors are said to be able to be used for 15 years, which is the target life of a vehicle, as long as they can be used, for example, by charging them when the system is operating and discharging them when the system is not operating. .

  In addition, by monitoring the capacitance value and the internal resistance, which are characteristic values of the capacitor, it is possible to determine the deterioration of the capacitor by grasping the change in the state.

As prior art document information related to the invention of this application, for example, Patent Document 1 is known.
JP-A-2005-94943

  An example (disassembled perspective view) of a conventional capacitor unit is shown in FIG.

  The plurality of capacitors 1 have their body portions held between holders 2. In this state, the lead wires 3 of the capacitors 1 are mounted on the wiring substrate 4 for the capacitors 1 by soldering.

  The capacitor block 5 thus completed is housed in the case 6.

  On the other hand, the circuit board 7 having the charge / discharge circuit of the capacitor 1 and the capacitor state detection circuit is housed in the case 6 in the vertical direction as shown in FIG.

  At this time, the circuit board 7 is fixed by tightening the screw 10 into the screw receiving portion 11 provided in the case 6 through the hole 9 provided in the heat sink 8 fixed to the circuit board 7 so that no stress is applied. Yes.

  Thus, by fixing the circuit board 7 in a so-called cantilever shape, it is configured to release thermal stress to the circuit board 7 in various temperature environments. As a result, deterioration due to thermal stress on the circuit board 7, the circuit components mounted on the circuit board 7, and the solder joints thereof is reduced, and the reliability is improved.

  In addition to the use of various noise countermeasure components (not shown) as countermeasures against disturbance noise, the circuit board 7 has a shield case 12 and a shield as shown in FIG. The structure is arranged inside the case lid 13.

  A capacitor unit is completed by attaching a cover (not shown) to the case 6 assembled in this way.

  The capacitor unit having such a configuration certainly has a sufficient performance as an auxiliary power source for vehicle braking, and can contribute to improving the reliability of hybrid cars and electric vehicles.

  However, as is clear from the structure of the capacitor unit shown in FIGS. 8 and 9, the capacitor part and the circuit part are separated from each other as a countermeasure against thermal stress, and in order to provide a reliable auxiliary power source for vehicle braking. A shield case for improving noise resistance was attached to the circuit board 7.

  Therefore, the conventional capacitor unit has a very high cost structure because it has a large number of parts and is difficult to manufacture.

  Although the capacitor unit is an indispensable unit especially for hybrid cars whose production volume has been increasing recently, its high cost has led to a rise in vehicle prices, which in turn has greatly increased the spread of hybrid cars that contribute to the protection of the global environment. Influence.

  Accordingly, the high cost of the capacitor unit due to the thermal stress avoidance structure and the noise resistance structure is a very big problem.

  The present invention solves the above-described conventional problems, and an object of the present invention is to provide a capacitor unit that satisfies the reduction of the influence of thermal stress, noise resistance, and low cost.

In order to solve the above-described conventional problems, the capacitor unit of the present invention includes a charge / discharge circuit that charges and discharges a capacitor, and a circuit board having a capacitor state detection circuit. Connect in series and parallel.
A lead wire of the capacitor has a bent portion, a tip of the bent portion is electrically connected to the circuit board, and a snap fit protrusion and a protrusion are provided on the holder, and the snap fit protrusion is provided on the snap fit protrusion. A snap-fit hole is provided in the corresponding circuit board, and the snap-fit protrusion is inserted into the snap-fit hole so that a gap is formed in the snap-fit hole . The holder is fixed to the circuit board by sandwiching the circuit board. The circuit board and the holder are fixed to different screw receiving portions among a plurality of screw receiving portions provided in the case by different configurations, and the holder receives screws through the holder holes provided in the holder. It is fixed by tightening the parts, the circuit board, between the fixed child cantilevered tighten the screw receiving portion provided with a screw to the case through the substrate holes, a washer provided on the circuit board in one window side It is attached to the case, and the diameter of the substrate hole is larger than the inner diameter of the washer and smaller than the outer diameter.

With this configuration, the capacitor unit has a single circuit board , and the thermal stress can be absorbed by the gap between the snap-fit protrusion and the snap-fit hole, the bent portion of the capacitor, and the board hole and washer. A case is unnecessary and it becomes a very simple structure. As a result, the object can be achieved.

  According to the capacitor unit of the present invention, since all circuit components are mounted on a single circuit board and only housed in a case, the number of components and man-hours can be reduced, and the cost of the capacitor unit can be reduced. it can.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

(Embodiment 1)
FIG. 1 is a partially exploded perspective view of a capacitor unit according to Embodiment 1 of the present invention. FIG. 2 is an enlarged view of a capacitor connecting portion to the circuit board of the capacitor unit according to the first embodiment of the present invention. 3 is a cross-sectional view of the connection portion between the circuit board and the case of the capacitor unit according to the first embodiment of the present invention. FIG. 3A is a cross-sectional view without a screw receiving protrusion, and FIG. 3B is a view with a screw receiving protrusion. Cross-sectional views are shown respectively. FIG. 4 is a perspective view of the heat sink to which the heat generating component of the capacitor unit according to Embodiment 1 of the present invention is attached. FIG. 5 is a cross-sectional view of the heat sink attached to the circuit board of the capacitor unit according to Embodiment 1 of the present invention.

  In each figure, the same components as those in FIGS. 8 and 9 of the conventional example will be described using the same reference numerals.

  In FIG. 1, the plurality of capacitors 1 are electric double layer capacitors, which are inserted into a holder 2 made of resin. Thereby, the trunk | drum of each capacitor 1 is clamped and integrated.

  Here, although 21 capacitors 1 are used in FIG. 1, there are 28 capacitors 1 in the conventional example (FIG. 8), and the quantities are different. This is because the power specifications of the capacitor unit are different, and a necessary quantity may be mounted according to the vehicle on which the capacitor unit is mounted.

  In this state, the lead wire 3 of the capacitor 1 is soldered to the circuit board 7.

  Here, since each capacitor 1 has a low allowable voltage of about 2V, a plurality of capacitors 1 are connected in series to the circuit board 7 to gain voltage, and to compensate for a decrease in capacitance due to the series connection. A wiring pattern is formed so as to form a so-called series-parallel circuit in which several sets of capacitors 1 connected in series are wired in parallel at the same time.

  Thereby, the capacitor 1 is electrically connected in series and parallel.

  The lead wire 3 has a crank-shaped bent portion 21 as shown in FIG. 2 (enlarged view of the dotted line portion in FIG. 1), and the tip is soldered to the circuit board 7. Thereby, the thermal stress applied to the lead wire 3 can be absorbed by the spring property of the bent portion 21.

  Further, the holder 2 is fixed to the holder screw receiving portion 201 with screws 10 directly to the circuit board 7.

  On the other hand, not all circuit components are shown on the circuit board 7, but a charging / discharging circuit for charging / discharging the capacitor 1, a capacitor state detection circuit, and a connector 22 for electrical connection with the outside of the capacitor unit are configured. Has been.

  Of the circuit components, a heat generating component 23 such as an FET is attached to the heat sink 8 and then fixed to the circuit board 7 together with the heat sink 8. These fixing methods will be described later.

  The circuit board 7 thus configured is inserted into the case 6.

  Since the case 6 is integrally provided with a plurality of screw receiving portions 11, the circuit board 7 fastens the screw 10 to the screw receiving portion 11 through the substrate hole 26 and washer 27 provided in the case 6, and is attached to the holder 2. The screw 10 is attached to the case 6 by tightening the screw 10 to the screw receiving portion 11 through the provided holder hole 28.

  With the configuration as described above, a conventional two-substrate can be simply made into one, and a simple configuration with the shield case removed can be obtained.

  However, as a result of the inventors conducting various characteristics studies on the capacitor unit as described above, the following problems have been discovered, and it has been found that the above simple configuration cannot be simply achieved.

  First, in the structure of FIG. 1, a shield case cannot be attached, and the problem that noise resistance is impaired is assumed.

  However, when various noise tests were conducted on the capacitor unit having the configuration shown in FIG. 1 without a shield case, no malfunction due to noise was observed, and sufficient noise resistance was ensured even without a shield case. confirmed.

  Therefore, it is sufficient to have various noise countermeasure components (not shown) provided on the circuit board 7, and the shield case is not necessarily required. As a result, there was no problem even if one substrate was used.

  Thus, it has been found that the cost can be reduced by eliminating the shield case and using one circuit board 7 from the viewpoint of noise alone.

  However, it became the problem of thermal stress that became the next problem by adopting such a structure.

  In the conventional configuration, as described above, in order to avoid the influence of the thermal stress on the circuit board 7, the circuit board 7 is fixed to the case 6 in a cantilever shape to avoid the problem of thermal stress.

  On the other hand, in the first embodiment, the circuit board 7 becomes large and cannot be fixed in a cantilever shape as in the prior art, and is fixed with six screws 10 as shown in FIG.

  In this state, when a thermal stress is applied to the capacitor unit by a thermal shock test, the circuit board 7 is fixed to the case 6 at six positions (four of which are via the holder 2 fixed to the circuit board 7 with screws not shown). Therefore, it was found that stress on the circuit board 7 is unavoidable, and the circuit board 7 itself, mounted circuit components, soldered portions, etc. are deteriorated and reliability is impaired.

  Therefore, in order to avoid thermal stress to the circuit board 7, the diameter of the board hole 26 is larger than the inner diameter of the washer 27 as shown in FIG. And it was set as the structure smaller than an outer diameter.

  As a result, a gap is always formed between the screw 10 and the board hole 26 as shown in FIG. 3A, and since the washer 27 is interposed, the screw 10 directly contacts the circuit board 7 and is fixed. Nothing will happen.

  On the other hand, the holder 2 is directly fixed to the case 6 with screws 10. In addition, since the heavy object called the capacitor 1 sandwiched between the holders 2 is mounted on one side of the circuit board 7, the holder 2 is firmly fixed to the case 6.

  Therefore, when a thermal stress is applied to the circuit board 7, the fixed portion on the holder 2 side does not move, and the substrate hole 26 provided near both ends of one side of the circuit board 7 farthest from the capacitor 1 is shown in FIG. Since this gap is formed, this portion absorbs expansion and contraction due to heat. This is because the circuit board 7 is not directly fixed by the screw 10, and therefore the circuit board in the horizontal direction of FIG. 3A at the contact surface of the washer 27 and the circuit board 7 and the contact surface of the circuit board 7 and the screw receiving portion 11. It is assumed that 7 can move out of position.

  When the capacitor unit having the above structure was actually subjected to a thermal shock test, it was confirmed that the circuit board 7, mounted circuit components, soldered portions, etc. did not deteriorate and the reliability was high.

  In this way, by adopting a structure in which the fixing method of the screw 10 is different between the holder hole 28 and the substrate hole 26, the influence of thermal stress can be reduced as in the conventional cantilever structure.

  As shown in FIG. 3B, the structure of the screw receiving portion 11 may be provided with a screw receiving protrusion 29 at the tip thereof.

  As a result, the gap portion of the substrate hole 26 is reduced as compared with FIG. 3A, but there is an effect that the screw receiving protrusion 29 facilitates positioning when the circuit board 7 is inserted into the case 6 when the capacitor unit is manufactured.

  Of course, in this case, the screw receiving projection 29 is slightly larger than the outer diameter of the screw thread so that a gap sufficient to absorb the thermal stress is formed as shown in FIG. The minimum required dimension is slightly lower than the thickness of the substrate 7.

  For the first time by adopting the above structure, a capacitor unit that is not affected by thermal stress can be configured even if the circuit board 7 is made into one sheet. As a result, it can be seen that the cost can be reduced based on this configuration. It was.

  Note that the location where the capacitor unit is installed may vary depending on the design of the vehicle manufacturer. In some cases, the temperature change range to which the capacitor unit is exposed is further expanded, and the thermal stress is assumed to be severe.

  In that case, there is a possibility that thermal stress cannot be sufficiently avoided with the basic configuration.

  Therefore, in order to cope with more severe conditions, as shown in FIG. 1, a plurality of holes arranged in a line between the mounting portion of the capacitor 1 and the other circuit component mounting portion on the circuit board 7, particularly an elongated hole, as shown in FIG. 1. 701 was provided.

  With this configuration, even if expansion and contraction due to heat is applied to the circuit board 7, the width of the elongated hole 701 is absorbed by the enlargement / reduction, and the effect of the board hole 26 described above is also added and absorbed twice. .

  Therefore, with the above-described configuration, a single substrate capacitor unit can be used even under more severe conditions.

  Although the elongated hole 701 is provided in the first embodiment, the shape is not limited to the elongated shape, and may be a round shape.

  In addition, although the elongated holes 701 are arranged in one row in the first embodiment, a plurality of rows may be provided. In this case, when the positions of the elongated holes 701 are particularly shifted in each row, the expansion and contraction due to the heat of the circuit board 7 that could not be absorbed by the portion between the elongated holes 701 adjacent to each other (the portion without the hole) in the case of one row. Since the elongated holes 701 in another row absorb, it can be absorbed evenly in the row direction of the circuit board 7 and the reliability of the circuit board 7 due to thermal stress can be further improved.

  Next, the structure of the heat sink 8 will be described as a cost-reducing structure other than the above.

  The conventional heat sink 8 shown in FIG. 8 is fixed to the circuit board 7 with screws. For this purpose, the heat sink 8 has screw holes (not shown) corresponding to mounting holes (not shown) of the heat sink 8 provided on the circuit board 7. (Not shown).

  Similarly, a screw hole (not shown) for fixing the heat generating component to the heat sink 8 is also provided in the portion where the heat generating component is attached.

  Since many of these screw holes were formed by cutting each of the heat sinks 8 by cutting, the processing cost was high.

  Therefore, the first embodiment is characterized in that a plurality of (two in the first embodiment) grooves 30a and 30b are provided in place of the screw holes of the heat sink 8 as shown in FIG.

  When attaching the heat generating element 23 to the heat sink 8, the tap screw 31 is tightened by aligning the mounting hole of the heat generating element 23 and the position of the groove 30a. Since the width of the groove 30 a is smaller than the thread of the tap screw 31, the groove 30 a is tightened while being shaved by the tap screw 31 by tightening the tap screw 31.

  With such a configuration, the heat generating element 23 can be fixed to the heat sink 8 without providing a screw hole as in the prior art.

  The heat sink 8 to which the heat generating element 23 is fixed in this way is aligned with the position of the mounting hole 702 of the heat sink 8 provided in the circuit board 7 and the groove 30b as shown in FIG. 5 (cross-sectional view of the dotted line in FIG. 4). Tighten. As a result, as described above, the tap screw 31 is tightened while cutting the groove 30b, and both are fixed.

  Since the grooves 30a and 30b provided in the heat sink 8 are formed by cutting, the processing cost remains high, so in the first embodiment, the grooves 30a and 30b are formed by extrusion molding. This eliminates the need for expensive cutting.

  In the first embodiment, aluminum is used as the heat sink metal that is easily extruded.

  Therefore, by pushing aluminum into a plurality of grooved molds, an original shape (long object) of the heat sink 8 in which a predetermined outer shape, the number of grooves, and a groove dimension are simultaneously formed can be formed. After that, the heat sink 8 can be formed at a very low cost if the heat sink 8 is cut for each length required.

  Further, since the grooves 30a and 30b are provided, if the grooves 30a and 30b exist, the distance between the mounting holes 702 of the heat sink 8 provided in the circuit board 7 and the mounting position of the heating element 23 can be freely changed. In addition, there is an effect that it is possible to easily cope with a design change of the wiring pattern at a low cost.

  With the above configuration, using a single circuit board with the shield case removed, and adopting a heat sink with a simple manufacturing method and structure, it is affected by noise characteristics and reliability due to thermal stress compared to conventional ones. In fact, a low-cost capacitor unit could be realized.

  Although the capacitor 1 is connected in series and parallel in the first embodiment, this may be connected only in series or only in parallel depending on the power specifications required for the system to be used.

(Embodiment 2)
FIG. 6 is a partially exploded perspective view of the capacitor unit according to the second embodiment of the present invention. FIG. 7 is a partial cross-sectional view of a portion where the holder of the capacitor unit according to the second embodiment of the present invention is attached to the circuit board.

  In each figure, the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  The second embodiment shows an example in which twelve capacitors 1 are connected in series and parallel.

  The feature of the second embodiment is that the snap fit protrusion 33 provided in the holder 2 is inserted into the snap fit hole 32 provided in the circuit board 7 in FIG. This is that a plurality of protrusions 34 (two in the second embodiment) are provided on the substrate 7 side.

  As shown in FIG. 7 (partially enlarged cross-sectional view of the dotted line portion in FIG. 6), the snap fit is a protrusion formed by tapering the tip and providing a step at the base of the taper. By inserting into a large opposing hole, the step is brought into contact with the opposing hole and mechanically connected due to the springiness of the protrusion. Below, the tip is tapered and the protrusion with a step at the base is snapped. The fitting protrusion 33 and the opposing hole are referred to as a snap fitting hole 32.

  By fixing in this manner, the circuit board 7 is sandwiched between the snap-fit protrusion 33 and the protrusion 34.

  With this configuration, the snap-fit projection 33 and the projection 34 are integrally formed with the holder 2, so that the screws used in the first embodiment when the holder 2 is fixed to the circuit board 7 are not necessary and are inserted. As a result, it is not necessary to have a screw tightening process, and it is possible to obtain a low cost effect in terms of both parts reduction and man-hour reduction.

  Further, by adopting such a configuration, the influence of the thermal stress on the circuit board 7 is further improved as compared with the first embodiment. This is due to the following reason.

  As shown in FIG. 6, the holder 2 is directly fixed to the case 6 with the screw 10 through the holder hole 28, but is fixed to the circuit board 7 by the spring property of the snap-fit protrusion 33. Therefore, the holder 2 is not firmly fixed to the circuit board 7 with screws as in the first embodiment.

  Accordingly, when a thermal stress is applied, a stress is directly applied from the case 6 to the holder 2, but a gap at the time of fitting between the holder 2 and the circuit board 7 in the snap-fit protrusion 33 and the snap-fit hole 32. Therefore, thermal stress can be absorbed in this gap. Since the protrusions 34 are only in contact with the circuit board 7 at two locations, the protrusions 34 do not directly transmit thermal stress to the entire circuit board 7.

  Further, a plurality of capacitors 1 are inserted in the holder 2, but the lead wire 3 is formed with a crank-shaped bending portion 21 as shown in FIG. Thermal stress can be absorbed by the spring property of the portion 21.

  For these reasons, when the circuit board 7 is fixed to the case 6 with the screw 10, it is fixed to the case 6 through the two screwing portions fixed to the case 6 through the board hole 26 and the holder hole 28. Between the two screwed portions, the gap between the snap fit projection 33 and the snap fit hole 32 and the bent portion 21 of the capacitor 1 function as a cushion, effectively absorbing thermal stress.

  With the above configuration, in addition to the absorption of the thermal stress by the substrate hole 26 and the elongated hole 701 described in the first embodiment, the above-described thermal stress absorption structure is applied to ensure a sufficient thermal stress reduction effect and A capacitor unit that can be further reduced in cost by the fit structure was realized.

  In the capacitor unit according to the present invention, all the circuit components are mounted on a single circuit board, and it is possible to achieve a structure in which the circuit unit is only housed in a case. It is useful as an emergency power source used in an electronic brake system that is electrically operated.

1 is a partially exploded perspective view of a capacitor unit according to Embodiment 1 of the present invention. FIG. 3 is an enlarged view of a capacitor connection part to the circuit board of the capacitor unit in the first embodiment of the present invention FIG. 2 is a cross-sectional view of the connection portion between the circuit board and the case of the capacitor unit according to the first embodiment of the present invention, (a) a cross-sectional view without a screw receiving protrusion, The perspective view of the heat sink which attached the heat-emitting component of the capacitor unit in Embodiment 1 of this invention Sectional drawing of the heat sink attached to the circuit board of the capacitor unit in Embodiment 1 of this invention The partial exploded perspective view of the capacitor unit in Embodiment 2 of the present invention Partial sectional drawing of the attachment part to the circuit board of the holder of the capacitor unit in Embodiment 2 of this invention Partially exploded perspective view of a conventional capacitor unit An exploded perspective view of a shield case of a conventional capacitor unit

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Capacitor 2 Holder 3 Lead wire 6 Case 7 Circuit board 8 Heat sink 10 Screw 11 Screw receiving part 21 Bending part 23 Heating component 26 Substrate hole 27 Washer 28 Holder hole 29 Screw receiving projection part 30a, 30b Groove 31 Tap screw 32 Snap fit hole 33 Snap-fit projection 34 Projection 701 Slot

Claims (7)

A plurality of capacitors in which the lead wire has a bent portion ; and
A holder for holding the body of the capacitor;
On the same substrate, a charging / discharging circuit for charging / discharging the capacitor by connecting to the lead wire and a capacitor state detecting circuit for detecting the state of the capacitor are provided, and the capacitors are electrically connected in series, or A circuit board connected and mounted in parallel or in series and parallel;
A case for housing the circuit board;
The circuit board and the holder are fixed to different screw receiving portions among a plurality of screw receiving portions provided in the case by different configurations,
The circuit board is fixed in a cantilever shape by fastening a screw to the screw receiving portion via a board hole and washer provided on one side of the circuit board, and the diameter of the board hole is larger than the inner diameter of the washer And the holder is formed smaller than the outer diameter, and the holder is fixed by tightening a screw to the screw receiving portion through a holder hole provided in the holder,
Provide a snap-fit protrusion and protrusion on the holder,
A snap fit hole is provided in the circuit board at a position corresponding to the snap fit protrusion,
The snap fit protrusion is inserted into the snap fit hole so that a gap is formed in the snap fit hole, and the circuit board is sandwiched between the snap fit protrusion and the protrusion, so that the holder is connected to the circuit. Capacitor unit fixed to the board. The capacitor unit according to claim 1, wherein the screw receiving portion is provided with a screw receiving protrusion that is larger than the outer diameter of the screw thread and lower than the thickness of the circuit board. The capacitor unit according to claim 1, wherein the capacitor sandwiched between the holders is mounted on one side of the circuit board, and board holes are provided in the vicinity of both ends of the one side of the circuit board farthest from the capacitor. The capacitor unit according to claim 1, wherein a plurality of protrusions are provided on the circuit board side of the holder. The capacitor unit according to claim 1, wherein a plurality of holes arranged in at least one row are provided between the capacitor mounting portion of the circuit board and the other circuit component mounting portion. The circuit board has a heat sink for attaching a heat generating component among the circuit components,
The heat sink is provided with a plurality of grooves,
The capacitor unit according to claim 1, wherein the circuit board and the heat-generating component are respectively attached by tightening a tap screw in the groove. The capacitor unit according to claim 6, wherein the heat sink is made of aluminum, and a plurality of grooves are simultaneously formed in the heat sink by extrusion molding.

Images