JP2018190791A - Pressure valve and electrolytic capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent both abrasive failure and contamination of an electrolytic capacitor.SOLUTION: A pressure valve 10 comprises a tapered region 22 of which the shape is tapered towards a tip 10b. In an apex 22t of the tapered region 22, an actuation part 23 is provided. While a case inner pressure is lower than a first predetermined value, the actuation part 23 maintains a closed state where air-tightness within a case is kept and when the case inner pressure reaches a value equal to or higher than the first predetermined value for the first time, the actuation part takes an open state where an opening is formed and a gas inside of the case is discharged through the opening to the outside of the case. After the opening is formed, while the case inner pressure is lower than a second predetermined value (where it leads the second predetermined value≤the first predetermined value), the closed state is maintained by closing the opening with an elastic force in the tapered region 22. While the case inner pressure is equal to or higher than the second predetermined value, on the other hand, the open state where the gas inside of the case is discharged through the opening to the outside of the case is maintained.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a pressure valve for an electrolytic capacitor and an electrolytic capacitor provided with the pressure valve.

  2. Description of the Related Art An electrolytic capacitor includes a case in which a capacitor element is accommodated, a sealing body that seals the case, and a pressure valve that closes a through hole formed in the sealing body (see Patent Document 1). . The pressure valve of Patent Document 1 (FIGS. 2 and 5) has a disk shape, and bursts when the case internal pressure reaches a predetermined value or more. Thereby, the gas inside the case is released.

JP 2005-93941 A

  The capacitor element accommodated in the case is impregnated with an electrolytic solution. When the case internal pressure reaches a predetermined value or more, the capacitor element is at a high temperature, and the electrolytic solution is evaporated in the case. When the pressure valve ruptures in this state, the electrolytic solution evaporates from the ruptured pressure valve together with the gas to the outside of the case, and the capacitance of the electrolytic capacitor decreases. As a result, the electrolytic capacitor can lead to wear failure. Also, contamination (contamination) from the outside of the case to the inside of the case through the ruptured pressure valve can be a problem.

  An object of the present invention is to provide a pressure valve and an electrolytic capacitor capable of preventing both electrolytic capacitor wear failure and contamination.

  The pressure valve according to the present invention is an electrolytic capacitor including a case in which a capacitor element is accommodated and a sealing body that seals the case, in a state where a base end is located inside the case and a tip is located outside the case The pressure valve is arranged so as to close the through-hole formed in the sealing body, and has a tapered region that becomes tapered as it approaches the tip, and an operating portion is provided at the top of the tapered region. When the case internal pressure is less than a first predetermined value, the operating part maintains a closed state that maintains airtightness inside the case, and the case internal pressure first reaches the first predetermined value or more. When an opening is formed and the gas inside the case is released to the outside of the case through the opening and the opening is formed, the internal pressure of the case is less than or equal to the first predetermined value. First Less than the predetermined value, the opening is closed and maintained in the closed state by the elastic force of the tapered region, while when the case internal pressure is equal to or higher than the second predetermined value, the gas inside the case is passed through the opening. It is configured to maintain the opened state of discharging to the outside of the case.

  An electrolytic capacitor according to the present invention includes a pressure valve according to the present invention, a sealing body in which the pressure valve is disposed, a case sealed by the sealing body, and a capacitor element accommodated in the case. It is characterized by being.

  According to the present invention, the pressure valve has a tapered region, and the operating portion capable of taking a closed state and an open state according to the internal pressure of the case is provided at the top of the tapered region. When the case internal pressure first reaches a first predetermined value or more, an opening is formed, and when the case internal pressure becomes less than a second predetermined value, the actuating portion is referred to as an elastic force in a tapered region (hereinafter referred to as “tightening force”). .), The opening is closed and the closed state is maintained. Thus, when the case internal pressure is equal to or higher than the first predetermined value, the gas inside the case can be discharged to the outside of the case through the opening of the operating portion, while when the case internal pressure is lower than the second predetermined value. The operating part can be maintained in the closed state by the tightening force. As a result, rupture of the pressure valve can be avoided and wear failure of the electrolytic capacitor can be prevented. The actuating part also has a check valve function (a function that maintains the closed state when the internal pressure of the case becomes less than the second predetermined value after the opening is formed), and releases the gas from the inside of the case to the outside of the case Permits only gas and prevents gas from entering the case from the outside. Thereby, contamination can be prevented.

  The first predetermined value is preferably 1.5 to 15 atm. In this case, the opening and closing of the opening can be stably performed while maintaining the mechanical strength of the operating portion.

  The ratio between the first predetermined value and the second predetermined value is preferably 1.1: 1 to 3: 1. In this case, the opening and closing of the opening can be stably performed. Furthermore, since the amount of the electrolytic solution released in the open state accompanying the initial opening formation can be reduced, it is possible to more reliably prevent the electrolytic capacitor from being worn out.

  Preferably, the top portion includes a thin portion and a thick portion having a thickness larger than that of the thin portion, and the operating portion is constituted by the thin portion. In this case, it is easier to form the operating portion than when the operating portion is made of a material different from the portion other than the operating portion at the top (for example, a material that is easier to break than the material other than the operating portion). Thus, it is possible to easily realize a configuration in which the operating portion selectively takes the open state and the closed state as described above.

  The operating portion may be linear as viewed from the thickness direction of the top portion. In this case, the tightening force is improved, and the check valve function can be reliably obtained.

  When viewed from the thickness direction of the top portion, the top portion may have a rectangular shape, and the operating portion may have a linear shape extending in the width direction of the top portion. When the top part is rectangular and the operating part is a straight line extending in the longitudinal direction of the top part, when the internal pressure of the case reaches a first predetermined value or more, the problem of opening to the periphery of the operating part, the pressure valve or this There may be a problem that the operating part is broken due to a pressure change or the like during transportation of the provided electrolytic capacitor, a problem that the check valve function cannot be reliably obtained, and the like. On the other hand, according to the said structure, since a top part is rectangular shape and an action | operation part is the linear form extended in the width direction of a top part, the said various problems can be suppressed.

  The tapered region may be formed in a truncated cone shape or a polygonal truncated cone shape. In this case, the tightening force is improved, and the check valve function can be reliably obtained.

  The side of the tapered region may be thicker than the top. In this case, the tightening force is improved, and the check valve function can be reliably obtained.

  The pressure valve according to the present invention is a valve main body that constitutes the distal end and is formed with the tapered region, at least a part of which is disposed in the through hole, and constitutes the base end, A casing provided on the inside of the case of the valve main body and having a diameter larger than that of the through hole may be provided. In this case, when the pressure valve is disposed on the sealing body, at least a part of the valve main body can be disposed in the through hole, and the housing can be attached to the wall on the case inner side of the sealing body. Thereby, even if a case internal pressure rises and a pressure valve is pressed to the case exterior side, it can prevent that a housing is caught on a wall and a pressure valve removes from a sealing body.

  According to the present invention, the pressure valve can be prevented from rupturing, and the electrolytic capacitor can be prevented from being worn out. Moreover, since the operation part has a check valve function, contamination can be prevented.

(A) is a top view of the electrolytic capacitor which concerns on 1st Embodiment of this invention. FIG. 2B is a partial cross-sectional view taken along line IB-IB in FIG. 1A, showing the overall configuration of the electrolytic capacitor according to the first embodiment of the present invention. It is a disassembled perspective view of a capacitor element. It is a figure corresponding to field III of Drawing 1 (b) which shows a pressure valve concerning a 1st embodiment of the present invention. (A) is a perspective view of a pressure valve concerning a 1st embodiment of the present invention. (B) is sectional drawing along the IVB-IVB line | wire of Fig.4 (a) of the pressure valve which concerns on 1st Embodiment of this invention. (A) is a top view of the pressure valve which concerns on 1st Embodiment of this invention, and shows the state which the opening of the action | operation part opened. (B) is a top view of the pressure valve concerning a 1st embodiment of the present invention, and shows the state where the opening of the operation part was closed. It is a figure corresponding to field III of Drawing 1 (b) showing the pressure valve of a 2nd embodiment of the present invention. (A) is a perspective view of a pressure valve concerning a 2nd embodiment of the present invention. (B) is sectional drawing along the VIIB-VIIB line | wire of Fig.7 (a) of the pressure valve which concerns on 2nd Embodiment of this invention. (A) is a top view of the pressure valve which concerns on 2nd Embodiment of this invention, and shows the state which the opening of the action | operation part opened. (B) is a top view of the pressure valve concerning a 2nd embodiment of the present invention, and shows the state where the opening of the operation part was closed.

<First Embodiment>
As shown in FIGS. 1A and 1B, the electrolytic capacitor 1 according to the first embodiment of the present invention includes a capacitor element 2, a case 3a, a sealing body 3b, a bottom plate 4, a sleeve 5, and a fixing material 6. , Terminals 7a, 7b and pressure valve 10.

  The case 3a accommodates the capacitor element 2, and a sealing body 3b is fitted in the opening. The sealing body 3b seals the case 3a. The case 3a is made of metal (aluminum or the like), and the sealing body 3b is made of an insulating material (modified phenol resin or the like).

  A packing 3x made of an elastic material (rubber or the like) is provided on the upper peripheral edge of the sealing body 3b. The packing 3x has a function of preventing gas inside the case 3a from leaking from the gap between the sealing body 3b and the case 3a. A packing 3x is fastened and fixed to the upper end of the case 3a.

  The bottom plate 4 is a circular film made of an insulating material (such as flame retardant polyester) and is disposed so as to overlap the bottom surface of the bottom of the case 3a. The sleeve 5 is a substantially cylindrical member made of an insulating material (polyolefin or the like), and covers the side peripheral surface of the case 3a, the lower peripheral edge of the bottom plate 4, and the upper peripheral edge of the case 3a. A bottom plate 4 is sandwiched between the lower portion of the sleeve 5 and the bottom of the case 3a.

  The fixing material 6 fixes the capacitor element 2 in the case 3a, and is made of a thermoplastic resin (polypropylene or the like).

  The terminals 7a and 7b and the pressure valve 10 are provided on the sealing body 3b. The terminals 7a and 7b are spaced apart from each other at positions that are point-symmetric with respect to the center of the sealing body 3b when viewed from the thickness direction of the sealing body 3b. The terminals 7a and 7b are made of metal (aluminum or the like). The cathode terminal 7 a is connected to the cathode lead 2 a (see FIG. 2) of the capacitor element 2, and the anode terminal 7 b is connected to the anode lead 2 b of the capacitor element 2.

  The sealing body 3b is formed with a through hole 30 that communicates the inside of the case 3a with the outside of the case 3a. The through hole 30 is provided between the center of the sealing body 3b (the center between the terminals 7a and 7b) and the outer edge of the sealing body 3b when viewed from the thickness direction of the sealing body 3b. The pressure valve 10 is disposed so as to close the through-hole 30, and is fixed to the sealing body 3b by a lock washer (not shown) disposed on the upper surface thereof. The pressure valve 10 is made of, for example, non-diene rubber (IIR, EPDM, silicone rubber, fluorine rubber, etc.) or diene rubber (CR, etc.).

  As shown in FIG. 2, the capacitor element 2 includes a cathode foil 2y to which a cathode lead 2a is attached and an anode foil 2x to which an anode lead 2b is attached via a separator (craft paper or the like) 2z made of an insulating material. The wound body is formed by winding and fixing the outer periphery of the wound body with an element stopper tape 2t (see FIG. 1B), and then impregnating the wound body with a driving electrolyte. The anode foil 2x and the cathode foil 2y are obtained by roughening the surface of an aluminum foil, and the anode foil 2x is obtained by forming an anodized film on the surface.

  Next, the pressure valve 10 will be described in detail with reference to FIGS.

  As shown in FIG. 3, the pressure valve 10 is disposed so as to close the through hole 30 with the base end 10a positioned on the inner side of the case 3a and the tip 10b positioned on the outer side of the case 3a.

  The pressure valve 10 includes a valve main body 11 constituting the distal end 10b and a housing 12 constituting the proximal end 10a. In the valve main body 11, more than half of the case inner side (about 3/5 of the total length along the axial direction of the through hole 30) is disposed in the through hole 30. The casing 12 is provided on the case inner side of the valve body 11, has a diameter larger than that of the through hole 30, and is attached to the wall 3bw on the case inner side of the sealing body 3b.

  As shown in FIGS. 4A and 4B, the valve main body 11 includes a cylindrical tube region 21 and a tapered region 22 provided outside the case in the tube region 21. The cylinder region 21 is a region having a constant diameter. The tapered region 22 has a tapered shape as it approaches the tip 10b (that is, toward the outside of the case).

  As shown in FIG. 4A, the top portion 22t of the tapered region 22 has a rectangular shape in plan view (as viewed from the thickness direction of the top portion 22t). The top portion 22t is formed with a linear actuating portion 23 extending in the width direction of the top portion 22t in plan view. The operating part 23 is a part that breaks before the other part of the pressure valve 10 when the internal pressure of the case 3a increases. As shown in FIG. 4B, the top portion 22t includes a thin portion constituting the operating portion 23 and a thick portion 24 having a thickness larger than that of the thin portion.

  The thickness of the thick portion 24 is the same as the thickness of each of the pair of side portions 22s of the tapered region 22, and is larger than the thickness of the thin portion (actuating portion 23). The pair of side portions 22s face each other across the top portion 22t, and are inclined so as to gradually approach each other as they approach the tip 10b.

  As shown in FIG. 4B, the pressure valve 10 is a hollow member opened on the base end 10a side.

  When the internal pressure of the case 3a is less than a first predetermined value (1.5 to 15 atm in the present embodiment), the operating unit 23 maintains a closed state that maintains airtightness inside the case 3a.

  The internal pressure of the case 3a reaches the first predetermined value or more, for example, when an anodic oxide film is formed on the cathode foil 2y by a reverse voltage, the anodic oxide film of the anode foil 2x is damaged by overvoltage or overcurrent, For example, when hydrogen gas is generated when the film damaged by the electrolytic solution is repaired. During the formation or repair of the film, the capacitor element 2 generates heat, so that the temperature inside the case 3a rises and the electrolyte solution evaporates inside the case 3a.

  When the internal pressure of the case 3a first reaches a first predetermined value or more, the operating portion 23 is broken, and an opening 23x is formed in the operating portion 23 as shown in FIG. After the opening 23x is formed, the internal pressure of the case 3a is a second predetermined value (here, second predetermined value ≦ first predetermined value. In the present embodiment, the first predetermined value and the second predetermined value). If the ratio is 1.1: 1 to 3: 1) or more, the open state of the opening 23x is maintained, and the operating unit 23 releases the gas inside the case 3a to the outside of the case 3a through the opening 23x. Keep open.

  Here, the opening 23x is much smaller than the opening formed by rupturing the pressure valve of Patent Document 1 (FIGS. 2 and 5). For this reason, even if the electrolytic solution evaporates inside the case 3a when the opening 23x is open, the electrolytic solution inside the case 3a is hardly discharged from the opening 23x.

  Thereafter, when the internal pressure of the case 3a becomes less than the second predetermined value, the opening 23x is closed by the elastic force (tightening force) of the tapered region 22 as shown in FIG. (A state in which the airtightness inside the case 3a is maintained) is maintained.

  After that, when the internal pressure of the case 3a reaches a second predetermined value or more, the opening 23x is opened as shown in FIG. 5A, and the gas inside the case 3a is brought out of the case 3a through the opening 23x. Released. Thereafter, when the internal pressure of the case 3a again becomes less than the second predetermined value, the opening 23x is closed as shown in FIG. 5B, and the airtightness inside the case 3a is maintained. Thus, opening and closing of the opening 23x is repeated.

  As described above, according to the present embodiment, as shown in FIG. 4A, the pressure valve 10 has the tapered region 22, and the case 3 a (FIG. 1B) is formed on the top 22 t of the tapered region 22. )) Is provided with an actuating portion 23 that can take a closed state and an open state in accordance with the internal pressure. The operating portion 23 is formed with an opening 23x (see FIG. 5A) when the internal pressure of the case 3a first reaches or exceeds the first predetermined value, and then the internal pressure of the case 3a is less than the second predetermined value. In this case, the opening 23x is closed by the elastic force (tight force) of the tapered region 22 to maintain the closed state (see FIG. 5B). Accordingly, when the internal pressure of the case 3a is equal to or higher than the first predetermined value (that is, when the internal pressure of the case 3a first reaches the first predetermined value or higher, and after the opening 23x is formed, the internal pressure of the case 3a is 2), the gas inside the case 3a can be released to the outside of the case 3a through the opening 23x of the operating portion 23, while the internal pressure of the case 3a is set to the second predetermined value. In the case of less than this, the operation part 23 can be maintained in the closed state by the tightening force. As a result, rupture of the pressure valve 10 can be avoided and wear failure of the electrolytic capacitor 1 can be prevented. Further, the actuating part 23 has a check valve function (a function of maintaining a closed state when the internal pressure of the case 3a becomes less than a second predetermined value after the opening 23x is once formed), and the case 3a is opened from the inside of the case 3a. Only the release of the gas to the outside of 3a is permitted, and the invasion of the gas from the outside of the case 3a to the inside of the case 3a is suppressed. Thereby, contamination can be prevented.

  In the present embodiment, the first predetermined value is 1.5 to 15 atmospheres. In this case, the opening and closing of the opening 23x can be stably repeated while maintaining the mechanical strength of the operating portion 23.

  In the present embodiment, the ratio between the first predetermined value and the second predetermined value is 1.1: 1 to 3: 1. In this case, the opening / closing of the opening 23x can be stably performed. In addition, since the amount of the electrolytic solution released in the open state accompanying the first opening 23x formation can be reduced, wear failure of the electrolytic capacitor 1 can be more reliably prevented.

  As shown in FIG. 4B, the top portion 22t includes a thin portion constituting the operating portion 23 and a thick portion 24 having a thickness larger than that of the thin portion. In this case, compared with the case where the action | operation part 23 is comprised with a material different from parts other than the action part 23 in the top part 22t (for example, material which is easy to fracture | rupture rather than the material of parts other than the action | operation part 23) etc. 23 can be easily formed, and the configuration in which the operating portion 23 selectively takes the open state and the closed state as described above can be easily realized.

  As shown in FIG. 4A, the operating portion 23 is linear as seen from the thickness direction of the top portion 22t. In this case, the tightening force is improved, and the check valve function can be reliably obtained.

  As seen from the thickness direction of the top portion 22t, as shown in FIG. 4A, the top portion 22t has a rectangular shape, and the operating portion 23 has a linear shape extending in the width direction of the top portion 22t. When the top portion 22t is rectangular and the operating portion 23 is a straight line extending in the longitudinal direction of the top portion 22t, there is a problem of opening to the periphery of the operating portion 23 when the internal pressure of the case 3a reaches a first predetermined value or more. In addition, there may be a problem that the operating part is broken due to a pressure change during transportation of the pressure valve 10 or the electrolytic capacitor 1 having the same, a problem that the check valve function cannot be obtained reliably, and the like. On the other hand, according to the said structure, since the top part 22t is rectangular shape and the action | operation part 23 is the linear form extended in the width direction of the top part 22t, the said various problems can be suppressed.

  As shown in FIG. 3, the pressure valve 10 is a valve body 11 that forms a tip 10 b and is formed with a tapered region 22 (see FIG. 4A). At least a part of the pressure valve 10 is disposed in the through hole 30. The valve main body 11 and the base end 10a are provided, and the housing 12 is provided on the inside of the case of the valve main body 11 and has a diameter larger than that of the through hole 30. In this case, when the pressure valve 10 is disposed on the sealing body 3b, at least a part of the valve body 11 can be disposed in the through hole 30, and the housing 12 can be attached to the wall 3bw on the case inner side of the sealing body 3b. Thereby, even if the case internal pressure rises and the pressure valve 10 is pressed to the outside of the case, it is possible to prevent the casing 12 from being caught by the wall 3bw and the pressure valve 10 from coming off the sealing body 3b.

Second Embodiment
As shown in FIG. 6, the pressure valve 210 according to the second embodiment of the present invention closes the through hole 30 with the base end 210a located on the inner side of the case and the distal end 210b located on the outer side of the case. Are arranged as follows.

  The pressure valve 210 includes a valve main body 211 that constitutes a distal end 210b and a housing 212 that constitutes a proximal end 210a. The valve body 211 is disposed in the through hole 30. The casing 212 is provided on the case inner side of the valve body 211, has a diameter larger than that of the through hole 30, and is attached to the wall 3bw on the case inner side of the sealing body 3b.

  As shown in FIGS. 7A and 7B, the valve main body 211 includes a substantially cylindrical tube region 221 and a tapered region 222 provided on the case outside of the tube region 221. The cylinder region 221 is a region having a substantially constant inner diameter. The tapered region 222 has a tapered shape as it approaches the tip 210b (that is, toward the outside of the case) and has a truncated cone shape.

  As shown in FIG. 6, ribs 221 a and 221 b are formed on the outer surface of the cylindrical region 221. The outer diameter of the portion where the ribs 221 a and 221 b are formed in the cylindrical region 221 is slightly larger than the diameter of the through hole 30. Therefore, when the valve body 211 is disposed in the through hole 30, the space between the cylindrical region 221 and the sealing body 3b is sealed by the ribs 221a and 221b.

  As shown in FIG. 7A, the top portion 222t of the tapered region 222 has a circular shape in plan view (viewed from the thickness direction of the top portion 222t). The top portion 222t is formed with a linear actuating portion 223 in plan view. The operating part 223 is a part that breaks before the other part of the pressure valve 210 when the internal pressure of the case 3a (see FIG. 1B) increases. As shown in FIG. 7B, the top portion 222t includes a thin portion constituting the operating portion 223 and a thick portion 224 having a thickness larger than that of the thin portion.

  The thickness of the thick part 224 is smaller than the thickness of the side part 222s of the tapered region 222 and larger than the thickness of the thin part (actuating part 223). The side part 222s is thicker than the top part 222t.

  As shown in FIG. 7B, the pressure valve 210 is a hollow member opened on the base end 210a side.

  Similarly to the operation unit 23 of the first embodiment, the operation unit 223 maintains a closed state in which the airtightness inside the case 3a is maintained when the internal pressure of the case 3a is less than the first predetermined value.

  When the internal pressure of the case 3a first reaches or exceeds the first predetermined value, the operating part 223 is broken, and an opening 223x is formed in the operating part 223 as shown in FIG. After the opening 23x is formed, if the internal pressure of the case 3a is equal to or higher than the second predetermined value, the state where the opening 223x is opened is maintained, and the operating unit 223 causes the gas inside the case 3a to pass through the opening 223x. 3a Maintains the open state of releasing to the outside.

  Thereafter, when the internal pressure of the case 3a becomes less than the second predetermined value, as shown in FIG. 8B, the opening 223x is closed by the elastic force (tightening force) of the tapered region 222, and the operating portion 223 is in the closed state. (A state in which the airtightness inside the case 3a is maintained) is maintained.

  Thereafter, when the internal pressure of the case 3a reaches a second predetermined value or more, the opening 223x is opened as shown in FIG. 8A, and the gas inside the case 3a is brought out of the case 3a through the opening 223x. Released. Thereafter, when the internal pressure of the case 3a again becomes less than the second predetermined value, the opening 223x is closed as shown in FIG. 8B, and the airtightness inside the case 3a is maintained. Thus, opening and closing of the opening 223x is repeated.

  As described above, according to the present embodiment, the following effects can be obtained in addition to the same effects based on the same configuration as that of the first embodiment.

  The tapered region 222 is formed in a truncated cone shape as shown in FIG. In this case, in the top part 222t, a force is applied to the area around the opening 223x toward the center of the top part 222t, and this force concentrates on the opening 223x and tries to close the opening 223x. Therefore, the tightening force is improved and the check valve function can be obtained with certainty.

  As shown in FIG. 7B, the side portion 222s of the tapered region 222 is thicker than the top portion 222t. In this case, the force for closing the opening 223x as described above can be further increased. Therefore, the tightening force is improved and the check valve function can be obtained with certainty.

  Hereinafter, the present invention will be described more specifically with reference to examples.

  In Examples No. 1 to No. 3, a pressure valve having the same configuration as that of the pressure valve 10 of the first embodiment (see FIGS. 3 to 5) was used. The pressure valve includes a housing 12 having a thickness of 1 mm, a valve body 11 having a height of 10 mm (a cylinder region 21 having a height of 5 mm, a tapered region 22 having a height of 5 mm), a housing 12 having an outer diameter of 7 mm, and a housing 12 having an inner diameter. 3.8 mm (the opening of the housing 12 is 3.2 mm), the outer diameter of the cylindrical region 21 is 4.8 mm, the inner diameter of the cylindrical region 21 is 3.8 mm (the thickness of the cylindrical region 21 is 1 mm), and the pair of side portions 22 s of the tapered region 22 Thickness 0.2mm, thickness 22mm of the thick portion 24 of the top portion 22t, thickness 0.1mm of the thin portion (actuating portion 23), long side 3.8mm of the top portion 22t, short side 0.4mm of the top portion 22t, The long side of the operation part 23 is 0.2 mm, and the short side (length in the width direction) of the operation part 23 is 0.1 mm.

  In the conventional examples No. 4 to No. 6, a disk-shaped pressure valve was used. The pressure valve has a diameter of 8 mm and a thickness of 0.45 mm.

  In No. 1 to No. 3 of the example and No. 4 to No. 6 of the conventional example, an electrolytic capacitor having the same configuration as the electrolytic capacitor 1 of the first embodiment (see FIG. 1) was used. The electrolytic capacitor has a diameter of 76.2 mm, a height of 90 mm, a diameter of a through-hole formed in the sealing body of 4 mm, a rated voltage of 400 V, and a capacitance of 4700 μF (a product with a guarantee of 5000 hours). The electrolytic capacitor was left to apply a rated voltage (400 V) at an ambient temperature of 105 ° C., and a reliability test was performed. Table 1 shows the parameters before the test (initial stage) and after 8000 hours. “Appearance” in Table 1 was judged by visual observation.

  In Examples No. 1 to No. 3, even when 8000 hours passed, the pressure valve was not ruptured (although the working part was broken and an opening was formed), and the electrolytic capacitor was worn out. Did not occur. Even after 8000 hours, the capacitance Cap, the loss angle tangent tan δ, and the wetting current LC did not change much. This is because an opening is formed in the operating portion when the case internal pressure firstly reaches a first predetermined value or more, or after the opening is formed, the case internal pressure reaches a second predetermined value or more to open the opening. Even if the gas inside the case is released to the outside of the case through the opening due to the open state, the opening is closed when the internal pressure of the case becomes less than the second predetermined value, and the airtightness inside the case Therefore, it is considered that the release of the electrolytic solution is suppressed and the capacitance Cap and the tangent tan δ of the loss angle hardly change. Moreover, even if 8000 hours passed, the pressure valve could continue to be used without rupturing.

  The first predetermined value was 7 atm, and the second predetermined value was 6 atm. Here, the first predetermined value is preferably 1.5 to 15 atm. By setting the first predetermined value to 1.5 to 15 atmospheres, the opening and closing of the opening can be stably performed while maintaining the mechanical strength of the operating portion.

  The ratio between the first predetermined value and the second predetermined value is preferably 1.1: 1 to 3: 1. By setting the ratio of the predetermined values to 1.1 to 3, the opening and closing of the opening can be stably performed. Furthermore, since the amount of the electrolytic solution released in the open state accompanying the initial opening formation can be reduced, it is possible to more reliably prevent the electrolytic capacitor from being worn out.

  On the other hand, in No. 4 to No. 6 of the conventional example, when 8000 hours passed, the pressure valve was ruptured, and wear failure occurred in the electrolytic capacitor. This is presumably because the electrolyte was discharged together with the gas from the rupture hole formed in the pressure valve, the capacitance Cap decreased to about half, and the loss angle tangent tan δ increased nearly 10 times.

  The preferred embodiments of the present invention have been described above, but the present invention is not limited to the above-described embodiments, and various design changes can be made as long as they are described in the claims.

  In the first embodiment, the operating portion has a linear shape extending in the width direction of the rectangular top portion, but may be a linear shape extending in the longitudinal direction of the rectangular top portion. Further, when viewed from the thickness direction of the top portion, the shape of the operating portion is not limited to a linear shape, and may be, for example, a circle, an ellipse, or a waveform.

  The operating part has the same thickness as the part other than the operating part at the top, and is made of a material different from the part other than the operating part at the top (for example, a material that breaks more easily than the material of the part other than the operating part). May be.

  When viewed from the thickness direction of the top, the shape of the top is not limited to a rectangle (FIG. 5) or a circle (FIG. 8), and may be an ellipse, for example.

  The tapered region has a truncated cone shape in the second embodiment, but may have a polygonal frustum shape (triangular pyramid shape, quadrangular pyramid shape, pentagonal pyramid shape, etc.).

  The pressure valve is not limited to including a valve body and a housing. For example, the pressure valve may include only a valve body without including a housing. Further, the valve body may be configured only by the tapered region without including the tube region.

DESCRIPTION OF SYMBOLS 1 Electrolytic capacitor 2 Capacitor element 3a Case 3b Sealing body 30 Through-hole 10; 210 Pressure valve 10a; 210a Base end 10b; 210b Tip 11; 211 Valve main body 12; 212 Housing 22; 222t Top 23; 223 Actuator (thin part)
23x; 223x Opening 24; 224 Thick part

Claims (10)

In an electrolytic capacitor including a case in which a capacitor element is accommodated and a sealing body that seals the case, the base end is formed on the sealing body in a state where the base end is located on the inner side of the case and the distal end is located on the outer side of the case. A pressure valve arranged to close the through-hole,
It has a tapered region that becomes a tapered shape as it approaches the tip, and an operating part is provided at the top of the tapered region,
The operating part is
When the case internal pressure is less than a first predetermined value, a closed state that maintains airtightness inside the case is maintained, and when the case internal pressure first reaches the first predetermined value or more, an opening is formed, Taking an open state in which the gas inside the case is released to the outside of the case through the opening,
After the opening is formed, when the internal pressure of the case is less than a second predetermined value that is equal to or less than the first predetermined value, the opening is closed by the elastic force of the tapered region, and the closed state is maintained. When the internal pressure is equal to or higher than the second predetermined value, the pressure valve is configured to maintain the open state in which the gas inside the case is released to the outside of the case through the opening.   The pressure valve according to claim 1, wherein the first predetermined value is 1.5 to 15 atm.   The pressure valve according to claim 1 or 2, wherein a ratio between the first predetermined value and the second predetermined value is 1.1: 1 to 3: 1. The top part includes a thin part and a thick part having a thickness larger than the thin part,
The pressure valve according to any one of claims 1 to 3, wherein the operating part is constituted by the thin part.   The pressure valve according to any one of claims 1 to 4, wherein the operating portion is linear when viewed from the thickness direction of the top portion.   6. The pressure valve according to claim 5, wherein the top portion has a rectangular shape when viewed from the thickness direction of the top portion, and the operating portion has a linear shape extending in a width direction of the top portion.   The pressure valve according to claim 1, wherein the tapered region is formed in a truncated cone shape or a polygonal truncated cone shape.   The pressure valve according to any one of claims 1 to 7, wherein a side portion of the tapered region is thicker than the top portion. A valve body that constitutes the tip and has the tapered region formed therein, at least a part of which is disposed in the through hole; and
9. A casing that constitutes the base end and is provided on the inside of the case of the valve body, the casing having a diameter larger than that of the through hole. The pressure valve according to any one of the above. The pressure valve according to any one of claims 1 to 9,
A sealing body in which the pressure valve is disposed;
A case sealed by the sealing body;
An electrolytic capacitor comprising a capacitor element housed in the case.

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