Liquid-tight connector and liquid-tight connector design method

Abstract

To attain reduction of a connector size while obtaining sufficient corrosion suppression effects.SOLUTION: A liquid-tight connector 1 comprises: a connector housing 11; a seal packing 23 which is provided in a seal area K12; and one or more corrosion-resistant packings 24 which are provided in a corrosion countermeasure area K13 on an upstream side of the seal area K12 in contact with a metal face C111 in one or more packing contact parts. Regarding the corrosion-resistant packing, in a case where there is one packing contact part, when a contact width of the packing contact part is defined as A1 and a contact width of a seal packing contact part is defined as H, a contact width size relation expressed as A1>H is established and in a case where there is a plurality of packing contact parts, when a contact width of a first packing contact part is defined as A1 and a contact width of a second packing contact part is defined as A2, a contact width size relation expressed as A1>A2 is established.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a liquid-tight connector in which a liquid-tight seal is provided between the outer surface of the connector housing and the metal surface covering it, and to a liquid-tight connector design method for designing this liquid-tight connector. [Background technology]

[0002] Conventionally, connectors have been used in which a portion of the housing outer surface is covered, for example, by the metal surface of a mating metal casing or the metal surface of a metal shell attached to the connector housing. In such cases, if the metal surface covering the housing outer surface is exposed to an environment where it may be exposed to liquids such as saltwater, there is a concern that the liquid may penetrate between the housing outer surface and the metal surface and cause corrosion of the metal surface due to the liquid. To address this issue, a liquid-tight connector is known that provides a packing in the liquid penetration path formed between the housing outer surface and the metal surface (see, for example, Patent Document 1). In the liquid-tight connector described in Patent Document 1, two packings are attached to the liquid penetration path, and these two packings are intended to prevent liquid penetration and corrosion of the metal surface. That is, the packing downstream of the penetration path mainly functions as a sealing packing that prevents liquid penetration. The packing upstream of this sealing packing functions as a corrosion-resistant packing that prevents corrosion in the section leading up to the sealing packing. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 7128237 specification Summary of the Invention [Problem to be solved by the invention]

[0004] In the liquid-tight connector described in Patent Document 1, the width of the inter-packing area between the sealing packing and the corrosion-resistant packing needs to be set to a certain extent in order to obtain a sufficient corrosion-inhibiting effect. However, such a wide inter-packing area may lead to an increase in the size of the connector, and therefore a liquid-tight connector is desired that can achieve a sufficient corrosion-inhibiting effect while also enabling a reduction in the size of the connector.

[0005] Therefore, the present invention focuses on the above-mentioned problems and aims to provide a liquid-tight connector that can achieve a sufficient corrosion inhibition effect while also achieving a reduced connector size, and a liquid-tight connector design method for designing such a liquid-tight connector. [Means for solving the problem]

[0006] In order to solve the above problems, the liquid-tight connector is a resin housing that accommodates connector terminals, and the connector housing has an outer surface that is partially covered with a predetermined metal surface; a sealing packing that is provided in a seal area set on the downstream side of a liquid infiltration path formed between the outer surface of the housing and the metal surface so as to contact the metal surface at a predetermined sealing packing contact portion; and a corrosion prevention area set on the upstream side of the seal area to suppress corrosion that progresses from an intrusion opening of the infiltration path to the metal surface due to the liquid, the sealing packing being provided in a corrosion prevention area set on the downstream side of the seal area so as to prevent corrosion that progresses from an intrusion opening of the infiltration path to the metal surface due to the liquid, the sealing packing being provided in a seal area set on the downstream side of the seal area so as to contact the metal surface at a predetermined sealing packing contact portion. and a corrosion-resistant packing having one or more packing contact portions arranged at one or more locations along the path, each of which is in contact with the metal surface, and in the case where there is one packing contact portion, when the contact width of the packing contact portion is A1 and the contact width of the sealing packing contact portion is H, the relationship of A1 > H holds; and in the case where there are multiple packing contact portions, when the contact width of a first packing contact portion which is the first from the inlet side is A1 and the contact width of a second packing contact portion is A2, the relationship of A1 > A2 holds.

[0007] In addition, in order to solve the above problem, a liquid-tight connector design method includes a resin housing that accommodates connector terminals, wherein a portion of the housing outer surface is covered with a predetermined metal surface; a sealing gasket that is provided in a sealing area set downstream of a liquid infiltration path formed between the housing outer surface and the metal surface so as to contact the metal surface at a predetermined sealing gasket contact portion; and a corrosion prevention area set upstream of the sealing area to suppress corrosion that progresses from the infiltration entrance of the infiltration path to the metal surface due to the liquid, wherein one or more gasket contact portions are provided in one or more locations along the infiltration path so as to each contact the metal surface. A liquid-tight connector design method for designing a liquid-tight connector having a corrosion-resistant packing, comprising: a sealing contact width determination step for determining the contact width of the sealing packing contact portion; and a corrosion-resistant contact width determination step for determining the contact width of one or more of the packing contact portions so that, when there is one packing contact portion, the contact width of the packing contact portion is A1 and the contact width determined in the sealing contact width determination step is H, where A1 is the contact width of the packing contact portion, and H is the contact width determined in the sealing contact width determination step; and, when there are multiple packing contact portions, the contact width of one or more of the packing contact portions is determined so that the contact width magnitude relationship expressed as A1>A2 is satisfied, where A1 is the contact width of a first packing contact portion that is first from the inlet side, and A2 is the contact width of a second packing contact portion that is second from the inlet side. [Effects of the Invention]

[0008] According to the liquid-tight connector and the liquid-tight connector design method described above, it is possible to reduce the size of the connector while still achieving a sufficient corrosion suppression effect. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a perspective view showing a liquid-tight connector according to one embodiment; [Figure 2] FIG. 10 is a perspective view showing another example of a liquid-tight connector. [Figure 3] FIG. 2 is an exploded perspective view of the liquid-tight connector shown in FIG. [Figure 4]4 is a cross-sectional view taken along line V11-V11 of the liquid-tight connector shown in FIG. 1, together with a cross-sectional view of the mating metal housing shown in FIG. 3. FIG. [Figure 5] FIG. 5 is an enlarged cross-sectional view of area F11 in FIG. 4. [Figure 6] FIG. 6 is a simplified schematic diagram of the enlarged cross section shown in FIG. 5. [Figure 7] 10 is an explanatory diagram for explaining setting of the width of the packing contact portion. FIG. [Figure 8] This is a table showing an example of verification data obtained by experiment that proves that the wider the first packing contact portion closest to the inlet, the slower the rate of corrosion between the packings in the area between the adjacent first packings at the back. [Figure 9] FIG. 9 is a graph showing the verification data shown in FIG. 8. [Figure 10] 10 is a diagram showing, in the form of a schematic diagram and a graph, the time it takes for corrosion to pass through a corrosion prevention area and reach a sealing area. FIG. [Figure 11] 1 is a diagram showing a schematic graph illustrating how corrosion is accelerated by contact between dissimilar metals and how corrosion is slowed down by the rust prevention effect. [Figure 12] 1 is a table showing an example of verification data obtained by experiment regarding acceleration of corrosion due to contact between dissimilar metals. [Figure 13] 1 is a table showing an example of verification data obtained by experiment to verify the deceleration of corrosion due to the rust prevention effect. [Figure 14] 14 is a schematic flowchart showing the flow of a liquid-tight connector design method for designing the liquid-tight connector described with reference to FIGS. 1 and 3 to 13. DETAILED DESCRIPTION OF THE INVENTION

[0010] An embodiment of a liquid-tight connector and a method for designing a liquid-tight connector will be described below.

[0011] FIG. 1 is a perspective view showing a liquid-tight connector according to one embodiment, and FIG. 2 is a perspective view showing another example of the liquid-tight connector.

[0012] The liquid-tight connector 1 shown in FIG. 1 is attached to the end of an electric wire W1 and is mated with the front side in the mating direction D11 entering the mating metal housing. Connector terminals 12 protruding from the front end in the mating direction D11 are connected to predetermined connections inside the metal housing. In this liquid-tight connector 1, a first gasket 13 and a second gasket 14 are attached to the outer surface of the connector housing 11, which is a cylindrical resin housing. The first gasket 13 and the second gasket 14 are sandwiched between the inner surface of a mating hole in the metal housing and the outer surface of the connector housing 11, thereby preventing liquid from penetrating through gaps between the outer surface of the connector housing 11 and the inner surface of the mating hole. In the liquid-tight connector 1 of this embodiment, various dimensions of the first gasket 13 and the second gasket 14 can be set during design as described below. This method of setting various dimensions can also be applied to other liquid-tight connectors, such as the following.

[0013] The liquid-tight connector 5 of another example shown in FIG. 2 is similar to the liquid-tight connector 1 of FIG. 1 in that the front side in the mating direction D51 enters the mating metal housing and the connector terminals 52 at the front end are connected to the mating terminals inside the metal housing. Meanwhile, in this liquid-tight connector 5 of another example, the front end of the connector housing 51 projects like a flange so as to be flush with the outer surface of the metal housing, and a single packing 53 is attached to the flange surface 511 at the front end. The packing 53 is formed in an annular shape surrounding the connector terminals 52 and has one ridge on each of the outer and inner sides. The ridge on the outer side is a first packing portion 531, and the ridge on the inner side is a second packing portion 532. In this example, the various dimensions of the first packing portion 531 and the second packing portion 532 can be set during design using the same setting method as for the liquid-tight connector 1 of the embodiment shown in FIG. 1. Therefore, the following description will be continued using the liquid-tight connector 1 of this embodiment as a representative example.

[0014] FIG. 3 is an exploded perspective view of the liquid-tight connector shown in FIG.

[0015] In the liquid-tight connector 1 of this embodiment, the connector terminal 12 at the end of the electric wire W1 is accommodated inside the connector housing 11 from the rear side in the mating direction D11. The electric wire W1 is held at the rear side of the connector housing 11 via a rubber stopper 15 and a rear holder 16. A first gasket 13 and a second gasket 14, both of which are annular rubber gaskets, are fitted into the housing outer surface 111 of the connector housing 11. The front side of the second gasket 14 is held and prevented from coming off by a front holder 17. A retainer 18 is disposed between the first gasket 13 and the second gasket 14, and the rear side of the second gasket 14 and the front side of the first gasket 13 are held by the retainer 18. A metal shield shell 19 and a rubber boot 20 are fitted over the rear side of the connector housing 11. The rubber boot 20 is held at its front side by a rubber boot band 21, and the shield shell 19 is held at its rear side by a shield ring 22.

[0016] A portion of this liquid-tight connector 1 that is closer to the front in the mating direction D11 than the shield shell 19 is fitted into the mating hole C11 of the mating metal housing C1, and the connector terminals 12 are fixed to a terminal block C12 inside the metal housing C1. In this mated state, a portion of the front side of the housing outer surface 111 of the connector housing 11 is covered with a metal surface C111 that forms the inner circumferential surface of the mating hole C11 of the metal housing C1. In the mated state, the first packing 13 and the second packing 14 are sandwiched between the housing outer surface 111 and the metal surface C111, and as will be described below, they prevent the intrusion of liquids such as saltwater and the progression of corrosion that occurs on the metal surface C111 as a result of this.

[0017] Fig. 4 is a diagram showing a cross section along line V11-V11 of the liquid-tight connector shown in Fig. 1, together with a cross section of the mating metal housing shown in Fig. 3. Fig. 5 is a diagram showing an enlarged cross section of area F11 in Fig. 4, and Fig. 6 is a simplified schematic diagram of the enlarged cross section shown in Fig. 5.

[0018] In this liquid-tight connector 1, when mated with the metal housing C1, a liquid infiltration path R11, indicated by the arrow, is formed between the housing outer surface 111 of the connector housing 11 and the metal surface C111 on the metal housing C1 side. The first packing 13 and the second packing 14 play a role in preventing the progress of liquid such as saltwater along this infiltration path R11 into the interior of the mating metal housing C1 and the progress of corrosion.

[0019] The first packing 13 is a rubber packing with one protrusion, and is disposed on the inlet side of the infiltration path R11. On the other hand, the second packing 14 is a rubber packing with two protrusions, and is disposed on the far side of the infiltration path R11. The far side protrusion of this second packing 14 serves as a sealing packing 23 that prevents liquid from penetrating into a waterproof area K11 located further back than the second packing 14. The sealing packing 23 is disposed in a sealing area K12 set downstream of the liquid infiltration path R11 so as to contact the metal surface C111 at a predetermined sealing packing contact portion 231. The sealing area K12 is the area obtained by adding the sealing packing contact portion 231 to the waterproof area K11.

[0020] The protrusions on the inlet side of the first packing 13 and the second packing 14 are multiple (two in this embodiment) corrosion-resistant packings 24 provided to suppress corrosion caused by liquid progressing from the inlet of the infiltration path R11 to the metal surface C111. These two corrosion-resistant packings 24 are provided upstream of the seal area K12 in a corrosion control area K13 set up to suppress corrosion caused by liquid progressing from the inlet of the infiltration path R11 to the metal surface C111. Of the two corrosion-resistant packings 24, the first packing 13 located on the inlet side is called the first corrosion-resistant packing 241, and the protrusions on the inlet side of the second packing 14 located at the back are called the second corrosion-resistant packing 242.

[0021] The first corrosion-resistant packing 241 contacts the metal surface C111 at a first packing contact portion 241a, which is the first from the inlet side, and the second corrosion-resistant packing 242 contacts the metal surface C111 at a second packing contact portion 242a, which is the second. The two corrosion-resistant packings 24 suppress the progression of corrosion on the metal surface C111 by contacting at these multiple (two in this embodiment) packing contact portions.

[0022] In this embodiment, the width of the packing contact portions arranged along the infiltration route R11 is set as follows.

[0023] Fig. 7 is an explanatory diagram for explaining the setting of the width of the packing contact portion. In Fig. 7, the direction of the liquid intrusion path R11 is shown in the left-right reversed direction compared to Figs. 4 to 6. Accordingly, in Fig. 7, the upper side in the drawing is the connector housing 11, and the lower side in the drawing is the metal casing C1.

[0024] 7 shows the packing contact portion closest to the inlet and the packing contact portion located adjacent to this packing contact portion on the rear side of the packing contact portion, among the packing contact portions lined up along the inlet path R11. In this embodiment, two corrosion-resistant packing contact portions and one sealing packing contact portion 231 are lined up from the inlet side. The packing contact portion closest to the inlet is the first packing contact portion 241a of the first corrosion-resistant packing 241, and the packing contact portion located adjacent to it on the rear side is the second packing contact portion 242a of the second corrosion-resistant packing 242. Further rearward of this second packing contact portion 242a, the sealing packing contact portion 231 of the sealing packing 23 is located adjacent to it. In this embodiment, when the contact width of the first packing contact portion 241a is A1 and the contact width of the second packing contact portion 242a is A2, the contact widths are set so that a relationship of A1>A2 holds.

[0025] In this embodiment, the two packing contact portions, the first packing contact portion 241a and the second packing contact portion 242a, are arranged side by side in the corrosion prevention area K13, so the above-mentioned contact width dimensional relationship is established. In contrast, unlike this embodiment, if only one packing contact portion is provided in the corrosion prevention area K13, the sealing packing contact portion 231 in the sealing area K12 is located adjacent to this packing contact portion. In this case, when the contact width of one packing contact portion in the corrosion prevention area K13 is A1 and the contact width of the sealing packing contact portion 231 is H, the contact width dimensional relationship expressed as A1 > H is established.

[0026] The above-described relationship between the contact widths is based on the following finding. When the liquid Lq1 enters the infiltration path R11, corrosion Cr1 first occurs on the metal surface C111 that comes into contact with the liquid Lq1 on the front side of the first anti-corrosion packing 241, which is closest to the infiltration opening. This corrosion Cr1 forms fine grooves on the metal surface C111, and the liquid Lq1 penetrates along these grooves, passing under the first anti-corrosion packing 241. As the liquid Lq1 penetrates, the corrosion Cr1 progresses, and the corrosion Cr1 reaches the first inter-packing area 25 between the first inter-packing and the second packing contact portion 242a on the far side. At this time, the rate at which the corrosion Cr1 progresses in the first inter-packing area 25 decreases as the width of the first packing contact portion 241a increases.

[0027] Fig. 8 is a table showing an example of verification data obtained by experimentation that the wider the first packing contact portion closest to the inlet, the slower the rate of inter-packing corrosion in the area between the adjacent first packings at the rear. Fig. 9 is a graph showing the verification data shown in Fig. 8.

[0028] In both Table Tb1 of FIG. 8 and Graph G1 of FIG. 9, the inter-packing corrosion rate is shown in units of mm / cycle, which represents the distance corrosion Cr1 progresses per cycle of a corrosion endurance test under predetermined evaluation conditions (Level 1). Table Tb1 of FIG. 8 also shows the contact corrosion rate when corrosion Cr1 progresses in the first packing contact portion 241a. Furthermore, when the width of the first packing contact portion 241a is 2.01 mm, the contact corrosion rate at the second packing contact portion 242a and the inter-packing corrosion rate between the second packing contact portion 242a and the sealing packing contact portion 231 are also shown. In Graph G1 of FIG. 9, the horizontal axis represents the inter-packing corrosion rate, and the vertical axis represents the width of the first packing contact portion 241a. As can be seen from Table Tb1 and Graph G1, the wider the width of the first packing contact portion 241a, the slower the rate of inter-packing corrosion progression. Based on this finding, in this embodiment, when the contact width of the first packing contact portion 241a is A1 and the contact width of the second packing contact portion 242a is A2, the contact widths are set so that a contact width relationship expressed as A1 > A2 holds. Based on the same finding, even when only one packing contact portion is provided in the corrosion prevention area K13, when the contact width of the one packing contact portion is A1 and the contact width of the sealing packing contact portion 231 is H, the contact width relationship expressed as A1 > H holds.

[0029] Here, as shown by the dotted approximation line in graph G1 of Fig. 9, the following decreasing proportional relationship is established between the width of the first packing contact portion 241a and the rate of progress of inter-packing corrosion. That is, when the width of the first packing contact portion 241a is A1, the rate of progress of inter-packing corrosion is Vb1, the slope coefficient is -C, and the intercept is D, [Number 6] Vb1=-C·A1+D Based on the example of graph G1 in Figure 9, [Number 7] A1=-10.575·Vb1+2.5503 This relation can be transformed into [Equation 6]: [Number 8] Vb1=(A1-2.5503) / -10.575 =-(1 / 10,575)·A1+(2.5503 / 10.575) This becomes:

[0030] Furthermore, in this embodiment, the following relationship holds for corrosion durability performance corresponding to the time it takes for the corrosion Cr1 to travel from the corrosion prevention area K13 to reach the seal area K12.

[0031] 10 is a diagram and graph showing the time it takes for corrosion to pass through the corrosion prevention area and reach the sealing area. In the diagram of Fig. 10, the intrusion path R11, connector housing 11, and metal casing C1 are shown in the same orientation as in the diagram of Fig. 7.

[0032] Graph G2 in FIG. 10 shows the progression time of corrosion Cr1 as the number of cycles (cycles), which is the number of times the corrosion durability test is repeated. In graph G2, the horizontal axis represents the number of cycles (cycles), and the vertical axis represents the progression distance (mm) of corrosion Cr1. As shown in graph G2, corrosion Cr1 progresses at a substantially constant rate through the first packing contact portion 241a of the first corrosion-resistant packing 241 and the second packing contact portion 242a of the second corrosion-resistant packing 242 in the corrosion treatment area K13. Corrosion Cr1 also progresses at a substantially constant rate through the first inter-packing area 25 between the first packing contact portion 241a and the second packing contact portion 242a and the second inter-packing area 26 between the second packing contact portion 242a and the sealing packing contact portion 231.

[0033] In this embodiment, the corrosion resistance performance corresponding to the time it takes for the corrosion Cr1 to travel from the corrosion prevention area K13 to reach the seal area K12 is expressed as follows.

[0034] First, the number of packing contact portions in the corrosion prevention area K13 is generalized from two in this embodiment to one or more, and the contact widths of these one or more packing contact portions are denoted as A1, A2, .... Furthermore, the number of inter-packing areas, including the area between the second packing contact portion 242a closest to the sealing area K12 and the sealing packing contact portion 231, is also generalized to one or more, and the widths of these one or more inter-packing areas are denoted as B1, B2, ....

[0035] Next, the contact corrosion progression speed when corrosion Cr1 progresses through one or more packing contact areas is defined as Va1, Va2, etc. from the inlet side. Also, the inter-packing corrosion progression speed when corrosion Cr1 progresses through one or more inter-packing areas is defined as Vb1, Vb2, etc. from the inlet side.

[0036] The corrosion durability performance is T, and the corrosion initiation index corresponding to the corrosion initiation time until corrosion Cr1 begins to progress at the first packing contact portion 241a closest to the inlet is T0. Then, the corrosion durability performance T is given as follows: [Number 9] T=T0+A1 / Va1+B1 / Vb1+A2 / Va2+B2 / Vb2+... The relationship expressed as follows holds.

[0037] In this case, when the relationship of [Equation 6] above is substituted into the inter-packing corrosion progression rate Vb1 of the first inter-packing area 25, [Equation 9] becomes: [Number 10] T=T0+A1 / Va1+B1 / (-C·A1+D)+A2 / Va2+B2 / Vb2+... It can be transformed as follows.

[0038] If dissimilar metal contact occurs outside the infiltration path R11, the effects of the dissimilar metal contact may extend to the inside of the infiltration path R11 via the liquid Lq1, and corrosion Cr1 occurring inside the infiltration path R11 may progress at an accelerated rate. Furthermore, resin members formed of silicone resin or the like containing oil with anti-rust properties may be used as the sealing gasket 23 and the anti-corrosion gasket 24. In this case, corrosion Cr1 inside the infiltration path R11 may progress at a slower rate due to the anti-rust effect of the oil in the resin member.

[0039] FIG. 11 is a schematic graph showing how corrosion is accelerated by contact between dissimilar metals and how corrosion is slowed down by the rust prevention effect.

[0040] In graph G3 of Figure 11, the progression of corrosion without the influence of galvanic contact and rust prevention is shown by a solid line, the influence of galvanic contact is shown by a dashed line, and the influence of rust prevention is shown by a dashed line. As can be seen from graph G3, corrosion Cr1 accelerates in the packing contact area and between packings when affected by galvanic contact, and slows down when affected by rust prevention. In this case, the relationship in [Equation 6], which represents corrosion durability performance T, can be corrected as follows to take into account the acceleration of corrosion Cr1 due to galvanic contact and the slowdown of corrosion Cr1 due to rust prevention.

[0041] First, the acceleration coefficient of corrosion Cr1 due to dissimilar metal contact is αA for the contact corrosion progression rate Va1, Va2,..., and αB for the inter-packing corrosion progression rate Vb1, Vb2,.... In this case, the relationship for corrosion durability performance T is as follows: [Number 11] T=T0+A1 / (Va1・αA)+B1 / (Vb1・αB)+A2 / (Va2・αA)+B2 / (Vb2・αB)+... This can be corrected to the relationship expressed as:

[0042] In addition, the deceleration coefficient of corrosion Cr1 due to the rust prevention effect is βA for the contact corrosion progression rate Va1, Va2,..., and βB for the inter-packing corrosion progression rate Vb1, Vb2,..., and the delay index corresponding to the delay in the corrosion start time due to the rust prevention effect is Tβ0. In this case, the relationship for corrosion durability performance T is as follows: [Number 12] T=T0+Tβ0+A1 / (Va1·βA)+B1 / (Vb1·βB)+A2 / (Va2·βA)+B2 / (Vb2·βB)+... This can be corrected to the relationship expressed as:

[0043] In addition, when both the acceleration of corrosion Cr1 due to dissimilar metal contact and the deceleration of corrosion Cr1 due to the rust prevention effect are taken into consideration, by combining [Equation 11] and [Equation 12], the relationship for corrosion durability performance T is as follows: [Number 13] T=T0+Tβ0+A1 / (Va1·αA·βA)+B1 / (Vb1·αB·βB)+A2 / (Va2·αA·βA)+B2 / (Vb2·αB·βB)+... This can be corrected to the relationship expressed as:

[0044] FIG. 12 is a table showing an example of verification data obtained by experiment to verify the acceleration of corrosion due to contact between dissimilar metals, and FIG. 13 is a table showing an example of verification data obtained by experiment to verify the deceleration of corrosion due to the rust prevention effect.

[0045] Table Tb2 in Figure 12 and Table Tb3 in Figure 13 both show the corrosion progression rate for each part under four evaluation conditions, Levels 1 to 4, which differ in the presence or absence of the effects of bimetallic contact and rust prevention effects, including Level 1, which is the evaluation condition for Table Tb1 in Figure 8.

[0046] Table Tb2 in Figure 12 shows that corrosion Cr1 accelerates and the corrosion rate increases when there is dissimilar metal contact (Levels 2 and 4) compared to when there is no effect (Levels 1 and 3). Regarding the contact corrosion rate Va1, Va2,..., a comparison between Levels 1 and 2 is used as a representative example, and the acceleration coefficient αA for corrosion Cr1 is 0·437 / 0.070 = 6.2. Furthermore, regarding the inter-packing corrosion rate Vb1, Vb2,..., a comparison between Levels 3 and 4 is used as a representative example, and the acceleration coefficient αB for corrosion Cr1 is 0.055 / 0.032 = 1.7.

[0047] Furthermore, Table Tb3 in Figure 13 shows that corrosion Cr1 is slowed down and the corrosion progression rate is slower when there is an effect of rust prevention (Levels 3 and 4) compared to when there is no effect of rust prevention (Levels 1 and 2). First, regarding the contact corrosion progression rates Va1, Va2,..., taking a comparison between Levels 1 and 3 as a representative example, the deceleration coefficient βA of corrosion Cr1 is 0·056 / 0.083 = 0.67.

[0048] In the verification shown in Table Tb3, the contact width A1 of the first packing contact portion 241a differs between Level 1 and Level 3. As described above, this difference in contact width A1 affects the inter-packing corrosion progression rate Vb1 in the adjacent first inter-packing area 25. That is, due to the decreasing proportional relationship between Equation 6 and Equation 8, the longer the contact width A1, the slower the inter-packing corrosion progression rate Vb1. To compare the inter-packing corrosion progression rate Vb1 between Level 1 and Level 3, the inter-packing corrosion progression rate Vb1 for Level 1 is converted using the contact width A1 for Level 3. The verification data in Table Tb1 of Figure 8, which is the basis for Equation 8, was obtained for Level 1. Therefore, when the inter-packing corrosion progression rate Vb1 is converted using the decreasing proportional relationship in Equation 8, Vb1 = (1.76 - 2.5503) / -10.575 = 0.074 [mm / cycle]. Using this conversion value, the deceleration coefficient βB for corrosion Cr1 for the inter-packing corrosion progression rates Vb1, Vb2, ... is 0.032 / 0.074 = 0.44, for example, when comparing Level 1 and Level 3 as a representative example.

[0049] Next, a liquid-tight connector design method for designing the above-described liquid-tight connector 1 will be described. In this liquid-tight connector design method, the above-described relational expressions [Equation 6] to [Equation 13] are used. Also, various parameters and coefficients obtained from the verification data in Tables Tb1 to Tb3 in Fig. 8, Fig. 12, and Fig. 13 are used.

[0050] FIG. 14 is a schematic flowchart showing the flow of the liquid-tight connector design method for designing the liquid-tight connector described with reference to FIGS. 1 and 3 to 13. In FIG.

[0051] The liquid-tight connector design method represented by the flowchart in Figure 14 includes a sealing contact width determination process S11, a tentative determination process S12, a speed acquisition process S13, a speed calculation process S14, an evaluation process S15, a packing spacing determination process S16, and a corrosion-resistant contact width determination process S17.

[0052] The sealing contact width determination step S11 is a step of determining the contact width H of the sealing packing contact portion 231. The contact width H of the sealing packing contact portion 231 is determined to be a length necessary from the viewpoint of preventing the liquid Lq1 from infiltrating into the sealing area K12.

[0053] The tentative determination step S12 is a step of tentatively determining the contact widths A1, A2, ... of one or more packing contact portions in the corrosion prevention area K13, and tentatively determining the widths B1, B2, ... of one or more inter-packing areas in the corrosion prevention area K13. At this time, the tentative determination is performed so that the contact width magnitude relationship expressed as A1>A2 holds between the contact width A1 of the first packing contact portion 241a and the contact width of the packing contact portion positioned adjacent thereto (in this embodiment, the contact width A2 of the second packing contact portion 242a).

[0054] The rate acquisition step S13 is a step of experimentally acquiring the contact corrosion progression rates Va1, Va2,... at the packing contact portions and the inter-packing corrosion progression rates Vb2,... in one or more inter-packing areas excluding the first inter-packing area 25. The acquisition here is performed using a predetermined simple model.

[0055] The rate calculation step S14 is a step of calculating the inter-packing corrosion progression rate Vb1 in the first inter-packing area 25 based on the contact width A1 of the first packing contact portion 241a provisionally determined in the provisional determination step S12. The decreasing proportional relationships expressed by the above-mentioned [Equation 6] to [Equation 8] are used in this calculation.

[0056] The evaluation step S15 is a step of estimating the corrosion durability performance T based on the tentative determination result in the tentative determination step S12, the result obtained in the speed acquisition step S13, and the result calculated in the speed calculation step S14, and evaluating the estimated result by comparing it with the required performance for the corrosion durability performance T. The relational expressions expressed by the above [Equation 9] to [Equation 13] are used to estimate the corrosion durability performance T. The tentative determination step S12 and the speed calculation step S14 are then repeated while changing each tentative value until the estimated result of the corrosion durability performance T exceeds the required performance. Note that in the speed acquisition step S13, once experimental speed acquisition is performed using a simple model corresponding to the design object, the acquired result is repeatedly used.

[0057] The packing spacing determination step S16 is a step of determining the widths B1, B2, . . . of one or more inter-packing areas based on the evaluation results in the evaluation step S15.

[0058] The corrosion-resistant contact width determination process S17 is a process for determining the contact widths A1, A2, ... of one or more packing contact portions based on the evaluation results in the evaluation process S15, which use the provisional determination results in the provisional determination process S12, in which the contact width magnitude relationship expressed as A1 > A2 holds.

[0059] In the packing spacing determination process S16 and the corrosion-resistant contact width determination process S17, provisional values ​​when the estimated corrosion durability performance T exceeds the required performance are determined as the design values ​​of the contact widths A1, A2, ... of the packing contact parts and the widths B1, B2, ... of the inter-packing areas.

[0060] In the liquid-tight connector design method of this embodiment, the liquid-tight connector 1 is designed by determining the shapes and dimensions of each part, such as the connector housing 11 and the shield shell 19, in addition to the above steps.

[0061] The liquid-tight connector 1 and the liquid-tight connector design method according to the embodiment described above can achieve the following effects. First, the sealing gasket 23 provided in the seal area K12 prevents the liquid Lq1 from penetrating further back than the seal area K12. Second, the corrosion-resistant gasket 24 provided in the corrosion control area K13 upstream of the seal area K12 prevents the corrosion Cr1 from progressing into the seal area K12. Here, the wider the contact width A1 of the first packing contact portion 241a that is closer to the liquid Lq1 inlet, the slower the rate at which the corrosion Cr1 progresses beyond the first packing contact portion 241a and into the corrosion control area K13. In this embodiment, the contact width A1 of the first packing contact portion 241a is wider than the contact width A2 of the second packing contact portion 242a that is adjacent to the first packing contact portion 241a and disposed on the far side. Furthermore, unlike the present embodiment, when the sealing packing contact portion 231 is adjacent to the first packing contact portion 241a, the contact width A1 of the first packing contact portion 241a is wider than the contact width H of the sealing packing contact portion 231. Setting such a contact width reduces the rate of corrosion Cr1 in the corrosion prevention area K13, and therefore, in anticipation of this corrosion prevention effect, the widths B1, B2, ... of the inter-packing areas can be reduced, i.e., the width of the corrosion prevention area K13 can be reduced. That is, according to the present embodiment, by setting the contact width A1 of the first packing contact portion 241a near the inlet wider, it is possible to obtain a sufficient corrosion prevention effect while reducing the width of the corrosion prevention area K13, thereby reducing the connector size.

[0062] In this embodiment, the contact width A1 of the first packing contact portion 241a and the inter-packing corrosion progression rate Vb1 in the area between adjacent packings satisfy a decreasing proportional relationship expressed by the above-mentioned [Equation 6]. According to this configuration, the contact width A1 of the first packing contact portion 241a can be set while accurately understanding the suppression effect of the inter-packing corrosion progression rate Vb1, i.e., the corrosion suppression effect, and therefore the design precision of the liquid-tight connector 1 can be improved.

[0063] Furthermore, in this embodiment, the corrosion resistance performance T is expressed by the above-mentioned relational expression of [Equation 9]. According to this configuration, using [Equation 9] as a clue, it is possible to set the contact widths A1, A2, ... of the packing contact portions and the widths B1, B2, ... of the areas between the packings in order to obtain the required corrosion resistance performance T, thereby improving the design efficiency of the liquid-tight connector 1.

[0064] Furthermore, in this embodiment, the corrosion durability performance T is expressed by the above-mentioned relational expression [Equation 11], taking into account the acceleration of corrosion Cr1 when dissimilar metal contact occurs outside the infiltration path R11. With this configuration, the contact widths A1, A2,... of the packing contact portions and the widths B1, B2,... of the inter-packing areas can be set taking into account the influence of dissimilar metal contact, thereby improving the design accuracy of the liquid-tight connector 1. Note that when the liquid-tight connector 1 is used in a location where dissimilar metal contact does not occur, there is no need to consider the influence of dissimilar metal contact, and 1.0 is substituted for the acceleration coefficients αA and αB in the relational expression [Equation 11]. In this case, the corrosion durability performance T is calculated by the above-mentioned relational expression [Equation 9].

[0065] Furthermore, in this embodiment, when resin materials containing oil that has a rust-preventing effect are used for the sealing gasket 23 and the corrosion-resistant gasket 24, the corrosion durability performance T is expressed by the above-mentioned relational expression

[12] , taking into account the deceleration of corrosion Cr1 due to the rust-preventing effect of the oil. This configuration allows the contact widths A1, A2,... of the gasket contact portions and the widths B1, B2,... of the inter-gasket areas to be set, taking into account the influence of the rust-preventing effect of the gasket material, thereby improving the design accuracy of the liquid-tight connector 1. Furthermore, when resin materials that do not contain the above-mentioned oil are used for the sealing gasket 23 and the corrosion-resistant gasket 24, it is not necessary to consider the influence of the rust-preventing effect, and 1.0 is substituted for the deceleration coefficients βA and βB in the relational expression

[12] . In this case, the corrosion durability performance T is calculated using the above-mentioned relational expression [9].

[0066] In this embodiment, the corrosion durability performance T is expressed by the above-mentioned relational expression [Equation 13], taking into account the acceleration of corrosion Cr1 due to dissimilar metal contact and the deceleration of corrosion Cr1 due to the rust prevention effect. This configuration allows the contact widths A1, A2,... of the packing contact portions and the widths B1, B2,... of the inter-packing areas to be set, taking into account the effects of dissimilar metal contact and the rust prevention effect, thereby improving the design accuracy of the liquid-tight connector 1. If it is not necessary to consider the effects of dissimilar metal contact and the rust prevention effect, 1.0 is substituted for the acceleration coefficients αA, αB and the deceleration coefficients βA, βB in the relational expression [Equation 13]. In this case, the corrosion durability performance T is calculated using one of the above-mentioned relational expressions [Equation 9], [Equation 11], or [Equation 12].

[0067] In this embodiment, the liquid-tight connector design method includes a tentative determination step S12, a speed acquisition step S13, a speed calculation step S14, an evaluation step S15, a packing spacing determination step S16 based on the evaluation results, and a corrosion-resistant contact width determination step S17. According to this configuration, the corrosion progression rate of each part is determined by a combination of experiments and calculations, and the contact widths A1, A2, ... of the packing contact parts and the widths B1, B2, ... of the inter-packing areas are determined by estimating and evaluating the corrosion durability performance T based on the results. By adopting such a determination method, the design efficiency of the liquid-tight connector 1 can be improved compared to determining various values ​​blindly by repeatedly creating samples and conducting durability tests.

[0068] Furthermore, in the present embodiment, in the rate calculation step S14, the inter-packing corrosion progression rate Vb1 is calculated using the decreasing proportional relationships expressed by the above-mentioned [Equation 6] to [Equation 8]. According to this configuration, by using the above-mentioned decreasing proportional relationships, the inter-packing corrosion progression rate Vb1 can be calculated efficiently with reduced man-hours.

[0069] Furthermore, in this embodiment, in the evaluation step S15, the corrosion durability performance T is estimated by applying the tentative determination result in the tentative determination step S12, the acquisition result in the speed acquisition step S13, and the calculation result in the speed calculation step S14 to the integration relationships of the above-mentioned [Equation 9] to [Equation 13]. According to this configuration, by using the integration relationships of [Equation 9] to [Equation 13], the corrosion durability performance T can be estimated efficiently while reducing the number of steps.

[0070] The above-described embodiments merely show typical examples of the liquid-tight connector and the liquid-tight connector design method. The liquid-tight connector and the liquid-tight connector design method are not limited to these, and can be implemented in various modifications.

[0071] For example, in the above-described embodiment, as an example of a liquid-tight connector, a liquid-tight connector 1 in which the sealing packing 23 and the second corrosion-resistant packing 242 are integrated as the second packing 14 is exemplified. Also exemplified is another example of a liquid-tight connector 5 in which all packings are integrated as a single packing 53. However, the liquid-tight connector is not limited to these, and may be one in which all packings, including the sealing packing, are provided as individual, single packings, etc.

[0072] Furthermore, in the above-described embodiment, as an example of a liquid-tight connector, the liquid-tight connector 1 is exemplified, which includes one sealing gasket 23 and two anti-corrosion gaskets 24. However, the liquid-tight connector is not limited to this, and any number of sealing gaskets and anti-corrosion gaskets may be installed.

[0073] Furthermore, in the above-described embodiment, the liquid-tight connector 1 in which the decreasing proportional relationship of [Equation 6] holds between the contact width A1 of the first packing contact portion 241a and the inter-packing corrosion progression rate Vb1 is exemplified as an example of a liquid-tight connector. However, the liquid-tight connector is not limited to this, and other relationships may hold between the two. However, as described above, the design precision of the liquid-tight connector 1 can be improved by holding the decreasing proportional relationship of [Equation 6].

[0074] Furthermore, in the above-described embodiment, the liquid-tight connector 1 whose corrosion durability performance T is expressed by the above-described relational expression [Equation 9] is exemplified as an example of a liquid-tight connector. However, the liquid-tight connector is not limited to this, and the corrosion durability performance may be obtained by preparing a sample product or the like and conducting a durability test. However, as described above, by being able to use the relational expression [Equation 9] as a clue, the efficiency of designing the liquid-tight connector 1 can be improved.

[0075] Furthermore, in the above-described embodiment, as an example of a liquid-tight connector, the liquid-tight connector 1 in which the corrosion durability performance T is expressed by the above-described relational expression [Equation 11] is given, taking into consideration the acceleration of corrosion Cr1 due to dissimilar metal contact. However, the liquid-tight connector is not limited to this, and the corrosion durability performance may be expressed by the relational expression [Equation 9], which excludes the influence of dissimilar metal contact. However, as described above, by being able to use the relational expression [Equation 11], which takes into account the influence of dissimilar metal contact, as a clue, the design accuracy of the liquid-tight connector 1 can be improved.

[0076] Furthermore, in the above-described embodiment, as an example of a liquid-tight connector, the liquid-tight connector 1 in which the corrosion durability performance T is expressed by the above-described relational expression [Equation 12] is given, taking into consideration the slowdown of corrosion Cr1 due to the anti-rust effect of oil contained in the packing. However, the liquid-tight connector is not limited to this, and the corrosion durability performance may be expressed by the relational expression [Equation 9], which excludes the influence of the anti-rust effect. However, as described above, by being able to use the relational expression [Equation 12], which takes into account the influence of the anti-rust effect, as a clue, the design accuracy of the liquid-tight connector 1 can be improved.

[0077] In the above-described embodiment, a liquid-tight connector design method including the following steps is exemplified as an example of a liquid-tight connector design method. That is, the liquid-tight connector design method of this embodiment includes a tentative determination step S12, a speed acquisition step S13, a speed calculation step S14, an evaluation step S15, a packing spacing determination step S16 based on the evaluation results, and a corrosion-resistant contact width determination step S17. However, the liquid-tight connector design method is not limited to this, and as long as it includes a sealing contact width determination step and a corrosion-resistant contact width determination step, the other steps can be set as appropriate. However, as described above, the design efficiency of the liquid-tight connector 1 can be improved by going through the above-described multiple steps.

[0078] Furthermore, in the above-described embodiment, as an example of the rate calculation step in the liquid-tight connector design method, a rate calculation step S14 is exemplified in which the inter-packing corrosion progression rate Vb1 is calculated using the decreasing proportional relationships expressed by the above-described [Equation 6] to [Equation 8]. However, the rate calculation step is not limited to this, and the specific calculation method is not limited to this. However, as described above, by using the decreasing proportional relationship, the inter-packing corrosion progression rate Vb1 can be calculated efficiently with reduced man-hours.

[0079] Furthermore, in the above-described embodiment, an evaluation step S15 is exemplified as an example of an evaluation step in the liquid-tight connector design method, in which the corrosion durability performance T is estimated using the integration relationships of [Equation 9] to [Equation 13] described above. However, the evaluation step is not limited to this, and the specific evaluation method is not limited to this. However, as described above, by using the integration relationships, the corrosion durability performance T can be estimated efficiently with reduced man-hours. [Explanation of symbols]

[0080] 1,5 Liquid-tight connector 11,51 Connector housing 12,52 Connector terminal 13 First packing 14 Second packing 15 Rubber stopper 16 Rear holder 17 Front holder 18 Retainer 19 Shield Shell 20 Rubber Boots 21 Rubber Boot Band 22 Shield Ring 23 Sealing packing 24 Corrosion-resistant packing 25 Area between first packings 26 Second packing area 53 Gasket 111 Housing outer surface 231 Sealing packing contact part 241 No. 1 Corrosion-Resistant Packing 241a First packing contact part 242 Second anti-corrosion packing 242a Second packing contact part 511 flange surface 531 First packing part 532 Second packing part A1, A2, ... Contact width of packing contact area B1, B2,... Width of the area between packings C1 Metal Case C11 Fitting hole C12 terminal block C111 Metal surface Cr1 corrosion D11 Mating direction G1,G2 graph H Contact width of seal packing contact area K11 Waterproof Area K12 Seal Area K13 Corrosion prevention area Lq1 liquid R11 Infiltration route S11 Sealing contact width determination process S12 Temporary determination process S13 Speed ​​acquisition process S14 Speed ​​calculation process S15 Evaluation process S16 Packing spacing determination process S17 Contact width determination process for corrosion resistance T Corrosion resistance performance Tβ0 delay index Tb1,Tb2,Tb3 table Va1, Va2,... Contact corrosion progression rate Vb1, Vb2,... Corrosion progression rate between packings W1 electric wire αA, αB acceleration coefficients βA, βB deceleration coefficients

Claims

1. a resin housing that accommodates connector terminals, the connector housing having an outer surface that is partially covered with a predetermined metal surface; a sealing packing provided in a seal area set downstream in a liquid infiltration path formed between the housing outer surface and the metal surface so as to contact the metal surface at a predetermined sealing packing contact portion; a corrosion-resistant packing provided in a corrosion prevention area set upstream of the sealing area to suppress corrosion progressing from the inlet of the infiltration path to the metal surface due to the liquid at one or more packing contact portions arranged along the infiltration path, the packing contact portions being in contact with the metal surface, wherein, when there is one packing contact portion, the contact width of the packing contact portion is defined as A1 and the contact width of the sealing packing contact portion is defined as H, such that A1 > H; and, when there are multiple packing contact portions, the contact width of a first packing contact portion that is first from the infiltration path is defined as A1 and the contact width of a second packing contact portion is defined as A2, such that A1 > A2; A liquid-tight connector comprising:

2. When the corrosion progresses in the inter-packing area beyond one packing contact portion or the first packing contact portion to the next packing contact portion, the inter-packing corrosion progress rate is Vb1, the slope coefficient is −C, and the intercept is D, [Equation 1] Vb1=-C・A1+D 2. The liquid-tight connector according to claim 1, wherein a decreasing proportional relationship expressed by the following expression holds:

3. The contact width of the packing contact portion and the width of one or more inter-packing areas in the corrosion prevention area, including the width between the packing contact portion closest to the sealing area and the sealing packing contact portion, are respectively defined as A1, A2, ..., B1, B2, ... from the inlet side, The contact corrosion progression rate when the corrosion progresses in the packing contact portion and the inter-packing corrosion progression rate when the corrosion progresses in the inter-packing area are respectively defined as Va1, Va2, ..., Vb1, Vb2, ... from the inlet side, T is a corrosion durability performance corresponding to the time it takes for the corrosion to pass through the corrosion prevention area and reach the seal area, When a corrosion initiation index corresponding to the corrosion initiation time until the corrosion starts to progress at the packing contact portion closest to the intrusion entrance is defined as T0, [Equation 2] T=T0+A1 / Va1+B1 / Vb1+A2 / Va2+B2 / Vb2+...

2. The liquid-tight connector according to claim 1, wherein the following relationship holds:

4. When dissimilar metal contact occurs outside the penetration path, the corrosion occurring inside the penetration path progresses in an accelerated state as the influence of the dissimilar metal contact extends to the inside of the penetration path through the liquid, When the corrosion acceleration coefficient is αA for the contact corrosion rate and αB for the inter-packing corrosion rate, the corrosion durability performance is as follows: [Equation 3] T=T0+A1 / (Va1・αA)+B1 / (Vb1・αB)+A2 / (Va2・αA)+B2 / (Vb2・αB)+...

4. The liquid-tight connector according to claim 3, wherein the following relationship holds:

5. When resin members containing oil having a rust-preventing effect are used as the sealing packing and the corrosion-resistant packing, the corrosion occurring inside the infiltration path progresses in a state where it is slowed down by the rust-preventing effect of the oil, a corrosion deceleration coefficient βA for the contact corrosion progression rate and a corrosion deceleration coefficient βB for the inter-packing corrosion progression rate; When the delay index corresponding to the delay in the corrosion onset time due to the rust prevention effect is Tβ0, the corrosion durability performance is as follows: [Equation 4] T=T0+Tβ0+A1 / (Va1・βA)+B1 / (Vb1・βB)+A2 / (Va2・βA)+B2 / (Vb2・βB)+...

4. The liquid-tight connector according to claim 3, wherein the following relationship holds:

6. When dissimilar metal contact occurs outside the infiltration path, the corrosion occurring inside the infiltration path progresses at an accelerated rate as the influence of the dissimilar metal contact extends to the inside of the infiltration path through the liquid, and when resin members containing oil having a rust-preventing effect are used as the sealing packing and the corrosion-resistant packing, the corrosion occurring inside the infiltration path progresses at a decelerated rate due to the rust-preventing effect of the oil, When the corrosion acceleration coefficient is αA for the contact corrosion rate and αB for the inter-packing corrosion rate, the corrosion deceleration coefficient is βA for the contact corrosion rate and βB for the inter-packing corrosion rate, and a delay index corresponding to the delay in the corrosion start time due to the rust prevention effect is Tβ0, the corrosion durability performance is as follows: [Equation 5] T=T0+Tβ0+A1 / (Va1・αA・βA)+B1 / (Vb1・αB・βB)+A2 / (Va2・αA・βA)+B2 / (Vb2・αB・βB)+...

4. The liquid-tight connector according to claim 3, wherein the following relationship holds:

7. A liquid-tight connector design method for designing a liquid-tight connector including: a resin housing that accommodates connector terminals, the connector housing having a portion of an outer surface of the housing covered with a predetermined metal surface; a sealing gasket that is provided in a seal area set downstream of a liquid infiltration path formed between the outer surface of the housing and the metal surface so as to contact the metal surface at a predetermined sealing gasket contact portion; and one or more corrosion-resistant gaskets that are provided in a corrosion prevention area set upstream of the seal area to suppress corrosion that progresses from an inlet of the infiltration path to the metal surface due to the liquid, the corrosion-resistant gaskets being arranged in one or more locations along the infiltration path so as to each contact the metal surface at a packing contact portion, a sealing contact width determination step of determining a contact width of the sealing packing contact portion; a corrosion-resistant contact width determination step for determining the contact width of one or more packing contact portions so that the relationship of A1>A2 holds when the contact width of the packing contact portion is A1 and the contact width determined in the seal contact width determination step is H, and when the packing contact portion is a plurality of packing contact portions, the contact width of a first packing contact portion that is the first from the inlet side is A1 and the contact width of a second packing contact portion that is the second from the inlet side is A2; A liquid-tight connector design method comprising:

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