Patent Application
20170045196
The present invention relates to a ventilation device forming a ventilation path, and a vehicular lamp.
For example, in Patent Document 1, a ventilation opening larger than 132 mm2 is covered with a ventilation unit for reducing condensation provided with at least one water vapor permeable material having an expanded PTFE membrane. It is described that, accordingly, elimination of condensed substances from the vehicular lamp is facilitated, to thereby provide protection not to allow external substances or liquid water to infiltrate.
An object of the present invention is, even though a protrusion in shape of a ventilation path including a bent part, which prevents infiltration of external substances and liquid water, from a housing is reduced, to make discharge of water vapor from a housing interior to the outside via the ventilation path successful.
Under such an object, the present invention is a ventilation device (10, 30, 50) for discharging water vapor in a housing interior (8) of a vehicular lamp (1) to an outside of the housing (2), the ventilation device including: an attachment part (11, 31, 51) to attach the ventilation device to a ventilation opening (9) of the housing while causing the ventilation device to be in communication with the ventilation opening; and a ventilation path (20, 40, 60) that is a hollow formed from an upstream side where the ventilation opening, which is in communication with the ventilation path via the attachment part, exists to a downstream side where a discharge port exists, the ventilation path including a bent part bending from a first direction (P) to a second direction (Q), wherein the ventilation path makes a cross-sectional area S2 of a cross section on an entrance side of the bent part orthogonal to the first direction larger than a cross-sectional area S1 of a cross section on an upstream side of the bent part orthogonal to the first direction, and constitutes a cross-sectional area S3 of a cross section on a downstream side of the bent part orthogonal to the second direction by continuing from the cross-sectional area S2 and bending to make a length in the first direction of an exit side of the bent part shorter than a length in the second direction of the cross-sectional area S1, and wherein the cross-sectional area S1≦ the cross-sectional area S3.
Here, the cross section of the ventilation path (20, 40, 60) forming the cross-sectional area S2 includes the cross section forming the cross-sectional area S1.
Moreover, the cross-sectional area S2 of the ventilation path (20, 40, 60) is a cross-sectional area of a cross section using a side (T2), which is a side constituting the cross-sectional area S3, a length of which in a direction orthogonal to the first direction is made longer than a length of the cross-sectional area S1 corresponding thereto.
Further, the ventilation path (40, 60) still bends from the second direction to a third direction (R).
Still further, the cross-sectional area S1 of the ventilation path (20, 40, 60) is 300 mm2 or more.
From another standpoint, the present invention is a ventilation device (70) that reduces fogging in a housing interior (8) of a vehicular lamp (1), the ventilation device including: a ventilation path support body (72) forming a ventilation path (80) that is in communication with a ventilation opening (9) in the housing (2) and is bent in a bent part from a first direction (P) to plural directions from an upstream side where the ventilation opening exists toward a downstream side, wherein the ventilation path support body forms the ventilation path that makes a cross-sectional area S2 of a cross section of an entrance side of the bent part orthogonal to the first direction larger than a cross-sectional area S1 of a cross section of an upstream side of the bent part orthogonal to the first direction, and constitutes a total cross-sectional area S3 of cross sections of a downstream side of the bent part orthogonal to the plural directions by continuing from the cross-sectional area S2 and bending to make a length in the first direction of an exit side of the bent part shorter than a length in the first direction in a case where a cross section constituting the cross-sectional area S1 is rotated 90°, and wherein the cross-sectional area S1≦ the total cross-sectional area S3.
A vehicular lamp (1) to which the present invention is applied includes: an electrical component (4) that emits light; a housing (2) that forms a space inside thereof including the electrical component; a ventilation opening (9) provided to the housing to discharge water vapor in a housing interior (8); and a ventilation path support body (10, 30, 50, 70) forming a ventilation path (20, 40, 60, 80) that is in communication with the ventilation opening and is bent in a bent part from a first direction (P) to a second direction (Q) or plural directions from an upstream side where the ventilation opening exists toward a downstream side, wherein, the ventilation path support body forms the ventilation path that makes a cross-sectional area S2 of a cross section on an entrance side of the bent part orthogonal to the first direction larger than a cross-sectional area S1 of a cross section on an upstream side of the bent part orthogonal to the first direction, and constitutes a cross-sectional area S3 of a cross section on a downstream side of the bent part orthogonal to the second direction or a total cross-sectional area S3 of cross sections orthogonal to the plural directions by continuing from the cross-sectional area S2 and bending to make a length in the first direction of an exit side of the bent part shorter than a length in the first direction in a case where a cross section constituting the cross-sectional area S1 is rotated 90°, and wherein S1≦S3.
Note that the above signs in this section are provided for exemplification in describing the present invention, and the present invention is not subjected to limited interpretation by these signs.
According to the present invention, it is possible to make discharge of water vapor from a housing interior to the outside via the ventilation path successful and to reduce a protrusion in shape of a ventilation path including a bent part, which prevents infiltration of external substances and liquid water, from a housing.
Hereinafter, exemplary embodiments according to the present invention will be described in detail with reference to attached drawings.
The vehicular lamp 1 to which the exemplary embodiments are applied is used as a head lamp, a rear lamp, a brake lamp, a fog lamp, a direction indicator lamp, a taxing lamp, a parking lamp, etc., of various kinds of vehicles typified by, for example, automobiles.
The vehicular lamp 1 shown in
Moreover, in the exemplary embodiments, the vehicular lamp 1 includes, as one of an aeration unit, a ventilation member 10 that performs transfer of air between interior and exterior of the lamp, and in particular, that is able to quickly discharge water vapor in the housing interior 8 to the exterior of the vehicular lamp 1. The ventilation member 10 is in communication with the ventilation opening 9 and forms a bending ventilation path, to thereby function as a ventilation path support body that supports the ventilation path. Then, the vehicular lamp 1 provided with the ventilation member 10 can be grasped as a mode of a ventilation device. Around the ventilation opening 9 in the housing 2, a protruding part 2a for attaching the ventilation member 10 is formed. By fitting the ventilation member 10 over the protruding part 2a, the ventilation member 10 can be attached to the housing 2.
The P-direction shown in
In general, an automobile lamp is provided with, as a function of discharging water vapor within the lamp to the outside and a function of canceling pressure difference caused by temperature change, a hole on a lamp housing side, and a ventilation member for dust-proofing and waterproofing is attached to the hole. Compatibility between the function of canceling the pressure difference and the dust-proofing and waterproofing property can be handled by a ventilation member, such as a PTFE (polytetrafluoroethylene) film. However, for the water vapor once infiltrated into the inside of the lamp, it is difficult to be discharged to the outside due to a complicated structure inside the lamp, to thereby cause a problem of condensation inside the lens surface by the temperature change. Moreover, if xenon or halogen is used for the lamp, it is possible to eliminate condensation by heat in lighting; however, for example, when an LED lamp is used, an amount of heat inside the lamp is decreased, and therefore, it becomes difficult to eliminate condensation by heat. Further, in a so-called hybrid vehicle or electric vehicle, electrical components are increased from a safety and environmental standpoint and converge into an engine room, and accordingly, there is a tendency of a shortage of space on the lamp housing side.
Here, in a ventilation device disclosed in Patent Document 1 (Japanese Patent No. 4276246), a sum of ventilation opening areas is 132 mm2 or more, and thereby, a certain functional role in water vapor permeability for eliminating condensation is fulfilled. However, if a PTFE film as the ventilation member is placed at an opening part as in the document for ensuring dust-proofing and waterproofing property, there occurs inferior permeability as compared to a through hole without ventilation material; therefore, it is impossible to respond high demands of defogging property in recent years by an opening of the order of 132 mm2 shown in the document. Moreover, it is possible to make a ventilation device thinner by placing the ventilation member separately at the opening part; however, if the ventilation member is directly protruded to the outside, there is a possibility that the ventilation member is broken by water pressure, collision of a flying stone or the like.
Therefore, in the exemplary embodiments, there is provided a ventilation device capable of discharging water vapor in the housing interior 8 to the outside of the lamp even if a lamp with a low amount of heat, such as an LED, as well as the lamp using xenon or halogen, is used. In other words, the ventilation member 10, which forms a ventilation path that has a constant shape or maintains a cross section of a certain size or more from the upstream side where the ventilation opening 9 exists toward the downstream side, and is bent at the bent part from the first direction (P-direction) to the second direction (Q-direction) or from the first direction to multiple directions, is employed.
The ventilation member 10 forms the ventilation path 20 configured with a void (through hole) as an inner tube, and functions as a ventilation device or a ventilation path support body. However, it is possible to define “ventilation device” to include, not only the ventilation member 10, but also the housing 2. The ventilation member 10 includes an attaching part 11 for attaching the ventilation member 10 to the ventilation opening 9 (refer to
The material of the ventilation member 10 may be a thermoplastic resin, a thermosetting resin, a metal or the like, and is not limited; however, from a standpoint of improving workability in attaching to the housing 2, it is preferable to use an elastic body, such as a thermoplastic elastomer or a thermosetting elastomer. Moreover, as a shape thereof, it is preferable to form the ventilation member 10 with a single material from a standpoint of reducing costs; however, the shape may be formed by injection molding or two-color molding using materials having different materials and hardness. Further, the shape or attaching method of the attaching part 11 of the ventilation member 10 conforms to the structure of the ventilation opening 9 of the housing 2, but is not limited and may be a circular shape, a rectangular shape, an elliptical shape or the like.
Moreover, it is possible to apply oil repellent treatment to the ventilation member 10. As the oil repellent treatment, specific examples include formation of an oil repellent coating including a polymer having perfluoro-alkyl group. The forming methods of the ventilation member 10 include coating of solution or dispersion of a polymer having perfluoro-alkyl group by an air spray method, an electrostatic spray method, a dip coating method, a spin coating method, a roll coating method, a curtain coating method, an impregnation method or the like, or, a coating forming method by an electrodeposition coating method or a plasma polymerization method. However, the method is not particularly limited as long as a desired coating can be formed.
As shown in
To put the above relation another way, the surface forming the cross-sectional area S2 (the cross section of the bent-part inlet side 22) of the ventilation member 10, which is the ventilation path support body, is larger than the surface forming the cross sectional area S1 (the cross section of the inlet-port side ventilation path 21), and S2 includes S1. Moreover, the cross-sectional area S2 is a cross section using a side (T2) constituting the cross-sectional area S3. The side (T2) is a length in the direction orthogonal to the first direction (P-direction), and the length thereof is longer than the length (T1) in the cross-sectional area S1 corresponding thereto. Note that “the direction orthogonal to” means “the direction intersecting at right angles to” in the exemplary embodiment; however, if the bending is not a right angle and is bent at an obtuse angle or an acute angle, the direction is “the direction obliquely intersecting”.
Here, in the exemplary embodiment, all of the cross-sectional areas S1, S2 of the ventilation path 20 and the area S3 of the opening is 300 mm2 or more. In other words, the ventilation member 10 forms the ventilation path 20 that is in communication with the ventilation opening 9 and is bent, and is configured to maintain the minimum cross-sectional area of at least 300 mm2 or more to the terminal end of the ventilation path including the bent part. The significance of the cross-sectional area of 300 mm2 or more will be described later.
Then, in the exemplary embodiment, for smooth movement of the water vapor and quickly discharging thereof to the outside, “the opening area of the ventilation path 20 of the ventilation member 10 connected to the outside of the lamp” is made “not less than the area of the ventilation opening 9 provided on the housing 2 side (the lamp housing side) as a function of discharging the water vapor to the outside and a function of eliminating pressure difference caused by the temperature change”; accordingly, the water vapor moves smoothly and is able to be discharged to the outside in a moment. The relations between respective opening areas are as follows.
cross-sectional area S1< cross-sectional area S2
cross-sectional area S1≦ cross-sectional area S3
In the exemplary embodiment, a through hole is employed as the ventilation path 20 formed in the ventilation member 10; however, the ventilation path 20 is not limited to the through hole. Even though the ventilation path 20 is a through hole, a bent ventilation path 20 is formed, and thereby it is possible to make water or dust from the outside harder to enter. Moreover, by setting the cross-sectional area S2 larger than the cross-sectional area S1, it is possible to make T2 large; accordingly, in the cross-sectional area S3 determined by T2×T3, T3 can be smaller than T1, to thereby make it possible to reduce the protruding amount of the ventilation member 10 in the P-direction.
In other words, to maintain smooth movement of the water vapor, the ventilation path 20 is required to maintain the opening area of a certain level or more to the terminal end; however, if the ventilation path 20 is bent while the ventilation path 20 remains to have the cross-sectional area S1 (if the cross section constituting the cross-sectional area S1 is rotated 90°), protrusion in the first direction (P-direction) becomes the length in the second direction of the cross-sectional area S1 (in other words, the protrusion in the first direction (P-direction) becomes the length T1), and thereby, the protruding amount becomes large. Particularly, in recent years, further improvement of the defogging property of a lamp has been required, and as a result, the area of the ventilation opening 9 was increased, and it was also necessary to increase the opening area of the ventilation path 20 of the ventilation member 10. On the other hand, downsizing of the device has been strongly required. Then, in the exemplary embodiment, the wide-width T2 was employed in the bent part; therefore, as the protrusion of the bent part in the P-direction, even if T3, which was the length smaller than the length of the cross-sectional area S1 in the second direction or the length in the case where the cross section constituting the cross-sectional area S1 was rotated 90°, was employed, it was possible to maintain the opening cross section of a certain level or more (for example, 300 mm2 or more), and thereby, it became possible to provide the ventilation member 10 that is thin in the P-direction while maintaining smooth movement of the water vapor.
Note that, as shown in
Next, a second exemplary embodiment of the ventilation member will be described.
The ventilation member 30 includes an attaching part 31 for attaching the ventilation member 30 to the ventilation opening 9 and for communicating the ventilation opening 9 with the ventilation path 40. Moreover, the ventilation member 30 includes a bent-part housing 32 that forms the bent part bending from the first direction (P-direction) to the second direction (Q-direction) in the inner tube used as the ventilation path 40. In the second exemplary embodiment, characteristics are present in further bending from the second direction (Q-direction) to a third direction (R-direction), and the bending to the third direction (R-direction) is also formed by the bent part housing 32.
The ventilation member 30 forms, by the attaching part 31 and the bent-part housing 32, the ventilation path 40 configured with an inlet-port side ventilation path 41 that is in communication with the ventilation opening 9 shown in
The cross sections of respective locations of the ventilation path 40 are similar to those of the first exemplary embodiment shown in
Then, in the exemplary embodiment, similar to the first exemplary embodiment, all of the cross-sectional areas S1, S2, S3 of the ventilation path 40 and the area S3 of the opening in the discharge port is 300 mm2 or more. In other words, the ventilation member 30 forms the ventilation path 40 that is in communication with the ventilation opening 9 and is bent, and is configured to maintain the minimum cross-sectional area of at least 300 mm2 or more to the terminal end of the ventilation path 40 including the bent part. Further, relations between the opening areas (cross-sectional area S1< cross-sectional area S2, cross-sectional area S1 cross-sectional area S3) are similar to those in the first exemplary embodiment. The ventilation path 40 being a through hole is also similar to the first exemplary embodiment.
As described above, in the second exemplary embodiment, the ventilation member 30, which is the ventilation path support body, includes the ventilation path 40 further bending from the second direction (Q-direction) toward the third direction (R-direction). This can reduce infiltration of water or dust from the outside more successfully. Moreover, since the cross section of 300 mm2 or more is maintained, even if the bending locations are increased, it becomes possible to provide the ventilation member 30 that is thin in the P-direction, which is related to the thickness from the attaching part, while maintaining smooth movement of the water vapor from the housing 2 side of the lamp. Further, since the direction of the discharge port 44 can be selected relatively freely, it becomes possible to select the orientation of the ventilation path 40 or the like; accordingly, degree of freedom in designing the vehicular lamp 1 as a whole can be increased.
Next, a third exemplary embodiment of the ventilation member will be described.
Here,
The third exemplary embodiment shown in
The ventilation member 50 includes an attaching part 51 for attaching the ventilation member 50 to the ventilation opening 9 and for communicating the ventilation opening 9 with the ventilation path 60. Moreover, the ventilation member 50 includes a bent-part housing 52 that forms the bent part bending from the first direction (P-direction) to the second direction (Q-direction) in the inner tube used as the ventilation path 60. In the third exemplary embodiment, similar to the second exemplary embodiment, the ventilation path 60 is further bent from the second direction (Q-direction) toward the third direction (R-direction). The ventilation member 50 forms, by the attaching part 51 and the bent-part housing 52, the ventilation path 60 configured with an inlet-port side ventilation path 61 that is in communication with the ventilation opening 9 shown in
The cross sections of respective locations of the ventilation path 60 are similar to those of the first and second exemplary embodiments shown in
Then, in the exemplary embodiment, similar to the first and second exemplary embodiments, all of the cross-sectional areas S1, S2, S3 of the ventilation path 60 is 300 mm2 or more. In other words, the ventilation member 50 forms the ventilation path 60 that is in communication with the ventilation opening 9 and is bent, and is configured to maintain the minimum cross-sectional area of at least 300 mm2 or more to the terminal end of the ventilation path 60 including the bent part. Further, relations between the opening areas (cross-sectional area S1< cross-sectional area S2, cross-sectional area S1 cross-sectional area S3) are similar to those in the first and second exemplary embodiments. The ventilation path 60 being a through hole is also similar to the first and second exemplary embodiments.
In this manner, in the third exemplary embodiment, the plural opening holes were configured as the discharge port 64. Then, the sum of the hole areas of the opening holes is 300 mm2 or more. A multiple number of opening holes may be provided to any locations in the course of the ventilation path. Though each of the opening holes is small, 300 mm2 or more can be ensured by summing thereof; for example, even if opening holes responding to a design request are used, it is possible to highly maintain the defogging property.
Next, a fourth exemplary embodiment of the ventilation member will be described.
Here,
The fourth exemplary embodiment shown in
The ventilation member 70 includes an attaching part 71 for attaching the ventilation member 70 to the ventilation opening 9 and for communicating the ventilation opening 9 with the ventilation path 80. Moreover, the ventilation member 70 includes a bent-part housing 72 that forms the bent part bending from the first direction (P-direction) to plural directions (in
As shown in
Then, in the exemplary embodiment, similar to the first to third exemplary embodiments, all of the cross-sectional areas S1, S2, and the total cross-sectional area S3 of the ventilation path 80 is 300 mm3 or more. In other words, the ventilation member 70 forms the ventilation path that is in communication with the ventilation opening 9 and is bent, and is configured to maintain the minimum cross-sectional area of at least 300 mm2 or more to the terminal end of the ventilation path including the bent part. Further, relations between the opening areas (cross-sectional area S1< cross-sectional area S2, cross-sectional area S1≦ cross-sectional area S3) are similar to those in the first to third exemplary embodiments. The ventilation path 80 being a through hole is also similar to the first to third exemplary embodiments.
In this manner, in the fourth exemplary embodiment, the plural opening holes were configured by providing the first discharge port 83 and the second discharge port 84 as the plural discharge ports. Then, the sum of the hole areas of the plural opening holes is 300 mm2 or more. In this manner, by forming the discharge port at the terminal end by use of one side (here, T5) of the bent-part inlet side 82 forming the bent part of the ventilation member 70, and further, by providing the plural discharge ports, even if the length in the depth direction (first direction, P-direction) is made shorter than the length in the first direction when the cross section constituting the cross-sectional area S1 is rotated 90°, it becomes possible to maintain good defogging property.
Subsequently, the ventilation member 10 (30, 50, 70) according to the present invention will be described in more detail by use of examples. Note that the present invention is not limited to the following examples.
After humidity control and water injection are performed as described below to the vehicular lamp 1 including the ventilation opening 9, the ventilation member 10 was attached to the ventilation opening 9, and then fogging reduction rate was measured.
In this example, as the ventilation member 10, a ventilation member 10 in a tubular shape including the bent part, with the inner diameter of 40 mm and the cross-sectional area of the ventilation path 20 of 1257 mm2 was used. In other words, the ventilation member 10 used in this example has the cross-sectional area of 1257 mm2 from one end of the ventilation path to the other end of the ventilation path including the bent part.
Moreover, as the vehicular lamp 1, a head lamp for a medium-sized vehicle with an internal volume of 6900 cc (HL of a 2011 model Genesis Coupé manufactured by Hyundai Mobis Ltd.) was used.
The vehicular lamp 1 including the ventilation opening 9 was left in a hot-dry condition (temperature: 80±2° C., relative humidity (RH): 10%) for 2 hours. Subsequently, while the ventilation opening 9 and the like were left open (without attaching the ventilation member 10), the vehicular lamp 1 was left in an ordinary temperature and pressure condition (temperature: 15° C. to 35° C., RH: 45% to 75%) for 1 hour. Thereafter, while the ventilation opening 9 was left open, the vehicular lamp 1 was left in a humidity control condition (temperature: 38° C., RH: 70%) for 1 hour, to thereby control the humidity in the housing interior 8 of the vehicular lamp 1.
To the ventilation opening 9 of the vehicular lamp 1 immediately after the above-described humidity control was performed thereon, the ventilation member 10 was attached. Then, after lighting for 20 minutes, the vehicular lamp 1 was turned off.
Thereafter, by use of a hose with an internal diameter of 19 mm, water injection to the vehicular lamp 1 in a turn-off state was conducted from the front side of the lens 3 for 3 minutes. Note that water of 10±2° C. water temperature was used while setting the water pressure at 100±20 kPa. Moreover, water injection was conducted while the tip of the hose was in a state being separated 10 cm from the lens 3 of the vehicular lamp 1 and water injection angle was changed from the vertical direction (90° upward with respect to the horizontal direction) to 30° upward with respect to the horizontal direction.
Subsequently, after lighting the vehicular lamp 1 for 10 minutes, the state of the lens 3 was observed until being defogged while the vehicular lamp 1 remained lighted, and thereby the fogging reduction rate of the lens 3 was measured.
Note that, in this example, “fogging reduction rate (%)” represents an elimination amount of the fog of the lens 3 after the elapse of a predetermined time after lighting the vehicular lamp 1 for 10 minutes. In this case, the fogging state of the lens 3 at the point of time when the vehicular lamp 1 has been lighted for 10 minutes (elapsed time is 0 minute) is assumed to be the fogging reduction rate of 0%. For example, the fogging reduction rate of 50% refers to the state in which the fog of the lens 3 is eliminated by half as compared to the state at the point of time when the vehicular lamp 1 has been lighted for 10 minutes (elapsed time is 0 minute). Moreover, the fogging reduction rate of 100% indicates the state in which all the fog of the lens 3 is eliminated (the state in which the fog does not occur on the lens 3 at all).
Usually, in the lamp, such as the vehicular lamp 1, it is possible to use the lamp without any concern for influence of the fog of the lens 3 if the fogging reduction rate is 80% or more.
In this example, the fogging reduction rate was visually measured by observing the lens 3 of the vehicular lamp 1 from the front side (from the outside of the vehicular lamp 1) at predetermined time intervals.
Note that, other than the measurement by visual observation, the fogging reduction rate may be calculated by, for example, photographing the lens 3 at predetermined time intervals and applying image processing on the photographed image.
Other than changing the inner diameter of the ventilation member 10 to be attached to the ventilation opening 9 of the vehicular lamp 1 and the cross-sectional area of the ventilation path, measurement of the fogging reduction rate of the lens 3 in the vehicular lamp 1 was conducted in a similar manner as Example 1.
Here, in Example 2, a ventilation member 10 in a tubular shape with the inner diameter of 30 mm and the cross-sectional area of 707 mm2 was used, and, in Example 3, a ventilation member 10 in a tubular shape with the inner diameter of 20 mm and the cross-sectional area of 314 mm2 was used. Moreover, in Comparative example 1, a ventilation member 10 in a tubular shape with the inner diameter of 15 mm and the cross-sectional area of 177 mm2 was used, and, in Comparative example 2, a ventilation member 10 in a tubular shape with the inner diameter of 10 mm and the cross-sectional area of 79 mm2 was used.
Other than providing three ventilation openings 9 to the vehicular lamp 1 and changing the ventilation member 10 to be attached to each ventilation opening 9, measurement of the fogging reduction rate of the lens 3 in the vehicular lamp 1 was conducted in a similar manner as Example 1.
As each ventilation member 10 to be attached to the ventilation opening 9, a rubber ventilation member 10 in a tubular shape with the inner diameter of 8.5 mm and the cross-sectional area of 57 mm2 was used, the ventilation member 10 including a bent part and a ventilation path filled with a porous sponge. Note that, in Comparative example 3, the sum of the cross-sectional areas of the three ventilation members 10 is 171 mm2.
As shown in
In other words, in the vehicular lamp 1 using the ventilation member 10 of Examples 1 to 3, it was confirmed that, even if fogging occurred on the lens 3, fogging was able to be eliminated to the extent that no influence was exerted on use in a short time, such as within 5 minutes.
In contrast thereto, in Comparative examples 1 to 3, it took more than 5 minutes to obtain the fogging reduction rate of lens 3 of 80% or more; therefore, it was confirmed that a longer time was needed to eliminate the fogging of the lens 3 as compared to Examples 1 to 3.
The elapsed time of 5 minutes is the time derived as a result of earnest study by the inventor and the like as a criterion about occurrence of trouble as a lamp used for a vehicle.
Moreover, from another standpoint, as shown in
In other words, it was confirmed that, by configuring the ventilation member 10 to maintain the minimum cross-sectional area of at least 300 mm2 or more to the terminal end of including the bent part, the fogging of the lens 3 was able to be quickly eliminated as compared to the case where the minimum cross-sectional area of the ventilation path was less than 300 mm2.
Subsequently, when Examples 1 to 3 were compared with one another, it was confirmed that, in Examples 1 and 2, the fogging reduction rate was able to be 80% or more in a shorter time as compared to Example 3. Moreover, when Examples 1 and 2 were compared with each other, despite the larger cross-sectional area of the ventilation path 20 in Example 1 as compared to Example 2, there was little difference in the fogging reduction rate.
Consequently, for obtaining good defogging property while suppressing infiltration of foreign substances into the housing interior 8 of the vehicular lamp 1 via the ventilation member 10 and suppressing upsizing of the ventilation member 10, it was confirmed that the minimum cross-sectional area of the ventilation member 10 was preferably of the order of 700 mm2.
Moreover, though illustration is omitted, when humidity control and water injection were performed and the vehicular lamp 1 was lighted for 10 minutes in a similar manner as Example 1, except for using the ventilation member 10 with the inner diameter of 60 mm and the cross-sectional area of 2826 mm2, it was confirmed that the fogging did not occur on the lens 3 (the fogging reduction rate is 100% in the elapsed time of 0 minute).
Note that, in the above-described Examples 1 to 3, the ventilation member 10 in a tubular shape including the bent part was used. However, as long as the ventilation member 10 includes the bent part and the minimum cross-sectional area of the ventilation path 20 (if the ventilation path is branched, the sum of the minimum cross-sectional areas of the plural ventilation paths) is at least 300 mm2 or more, regardless of the shape thereof, for example, even with the shape of the ventilation member 30, 50 or 70 shown in
As described in detail above, the present inventor and the like found that the defogging property could be kept at a high level by maintaining the minimum cross-sectional area of 300 mm2 or more up to the terminal end of the ventilation path (20, 40, 60, 80) including the bent part. Particularly, in recent years, improvement in quality of various kinds of lamps is called for and further improvement of the defogging property is demanded; if the improvements are to be achieved by the hollow ventilation member, it is necessary to provide, as described above, the cross-sectional area of the opening is 300 mm2 or more. Moreover, on the other hand, it is required to bend the hollow ventilation member for ensuring the dust-proofing and waterproofing property. The tubular structure configured with the circular cross section of 300 mm2 or more has a diameter of about 20 mm; if the tubular structure is directly bent, protrusion by the bent part alone becomes larger than 20 mm. On the depth side of the vehicular lamp 1, for example, an engine room or the like exists and various kinds of appliances, such as an electronic control unit (ECU), and the like are gathered, and accordingly, it is not preferable that the tubular structure is directly protruded because of space problems. According to the exemplary embodiments, it becomes possible to bend the ventilation path (20, 40, 60, 80) at a narrow portion thereof while maintaining a sufficient cross-sectional area throughout the ventilation path.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2014-089226 | Apr 2014 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2014/084259 | 12/25/2014 | WO | 00 |
