JPH0345372Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to an automobile headlamp with a ventilation hole.

[Conventional technology]

The ventilation holes of an automobile headlamp basically have small holes 21a and 21b on both end faces as shown in FIG.
A desiccant 22 such as silica gel is placed in a container 21 having a
The container 21 is filled with a container 21 and the housing 23 is passed through the container 21. Note that 24 is a lens.

In an automobile headlamp equipped with a vent having the above structure, the pressure increase within the headlamp is suppressed by the vent. Further, the air flowing in from the outside is dehumidified by the desiccant 22.

The desiccant 22, which has become hygroscopic due to the dehumidification of the air flowing in from the outside, is dried by the heat generated when the lamp is lit.
Release moisture. In other words, it has a recycling effect.

In addition, in order to reduce contact with outside air as much as possible, the housing 2 of the container 21 is closed as shown in FIG.
A porous resin membrane 25 having air permeability may be provided at the outer end of the tube 3, or a mechanical valve 26 may be used to shut off the outside air as shown in FIG.

[Problem that the invention attempts to solve]

However, when the desiccant 22 is given a recycling effect in this way, it can be expected that the moisture released from the desiccant 22 due to the temperature rise during lighting will be discharged to the outside by the internal pressure of the headlamp.
After a certain period of time has elapsed, the flow of air flowing out from inside the head lamp stops, so if the amount of moisture absorbed by the desiccant 22 is large, the release of moisture will continue after this.
The moisture also flows into the headlamp through the small hole 21a in the end face of the housing 23 of the container 21.

Moreover, at this point, the inside of the container 21 is in a high temperature and humidity state, and the flow of air flowing into the interior when the lamp is turned off causes this high temperature and humidity air to be transferred to the desiccant 2.
The moisture flows into the housing 23 without being absorbed by the moisture.

On the other hand, a porous resin membrane 25 is used to block outside air.
Alternatively, if the valve 26 is provided, the membrane 25 or the valve 26 not only prevents the moisture released during the above-mentioned ventilation process from being discharged to the outside, but also encourages the moisture to flow into the interior. . Moreover, since the mechanical valve structure requires a function to control the flow of air through the vent, the structure is complicated and large, resulting in high cost.

[Means for solving problems]

The present invention provides an automobile headlamp with a desiccant container extending both inside and outside the housing, and stores the desiccant inside the container. A porous resin membrane with air permeability is placed between the small holes on the inside side and the desiccant, and a porous resin membrane with higher air permeability than the above porous resin membrane is placed between the small holes on the outside of the housing and the desiccant. A filter is installed to prevent the outflow of chemicals and the inflow of water, dust, etc., and the amount of air that flows out of the housing when the headlamp is on, and the amount of air that flows into the housing when the headlamp is turned off. It is characterized by a time change that reaches a peak after a certain period of time and then gradually decreases.

〔Example〕

Figure 1 shows an embodiment of the present invention, in which 1 is a housing, 2 is a lens, 3 is a bulb (light bulb),
4 is a container having a small hole 4a on one end surface;
The housing 1 is penetrated so that the small hole 4a is located inside. L at the other open end of this container 4
The shaped tubes 5 are connected in series. This L-shaped tube 5 has a small hole 5a at the end surface where it joins the container 4. A porous resin membrane 6 with air permeability is provided at the end of the container 4 on the small hole 4a side, and a filter 7 is provided at the other end, and the inside is filled with a desiccant 8 such as silica gel. There is.

The mounting position of the container 4 is preferably a location where the temperature changes as rapidly as possible when the lamp is turned on and off. This is because moisture absorption and moisture release of the desiccant are highly temperature dependent, and temperature changes are to be made more rapid with respect to changes in outflow and inflow.

FIG. 2 shows the changes in humidity inside the lamps when a headlamp with a ventilation hole of the above structure and a headlamp with a conventional structure of ventilation holes are repeatedly turned on and off under high temperature and high humidity. In the figure, curves l ₁ and l ₂ are the characteristics of this embodiment, and curves l ₂₁ and l ₂₂ are the conventional characteristics. Characteristic curves l ₂ and l ₂₂ are for the case where the desiccant is in a hygroscopic state.

In the conventional case, if the desiccant is sufficiently dry, the hot and humid air flowing in from the outside will be dehumidified to some extent, but if the desiccant absorbs moisture, the desiccant will release moisture instead of dehumidifying it. It will act as a liquid and fog up the headlamp.

On the other hand, in the case of this embodiment, a sufficient dehumidifying effect can be obtained not only when the desiccant 8 is dry, but also when it absorbs moisture. Moreover, the recycling effect clearly appears in the form of a decrease in humidity in the hygroscopic state.

Figure 3 shows the change over time in the amount of air flowing out through the ventilation holes when the lamp is lit.
The curve _l23 is the characteristic of the conventional example, and the curve _l3 is the characteristic of this embodiment.

In the conventional example, the amount of outflow is maximum immediately after lighting, and decreases rapidly thereafter. Therefore, the moisture released from the desiccant whose temperature continues to rise is no longer discharged to the outside, but remains inside the vent or flows into the housing through the small hole 21a. The time change in the amount of air flowing into the interior through the ventilation holes when the lights are off is exactly the same as the time change when the lights are on. Therefore,
A large amount of air flows in in a short period of time. At this point, the desiccant is still at a high temperature and no dehumidifying effect can be expected, so it flows into the housing without being dehumidified.

On the other hand, in the case of this embodiment, the temporal changes in the outflow and inflow amounts reach a peak after a certain period of time, and then gradually decrease. This is due to the effect of the air-permeable porous resin membrane 6 between the internal small pores 4a and the desiccant 8.

As a result, when the light is turned on, the outflow of gas starts after the moisture release from the desiccant 8 begins, and as the moisture release increases, the outflow amount also increases, and even after the outflow amount reaches its peak, the outflow amount continues for a long time. is ensured, and the discharge of released moisture to the outside is sustained. In addition, when the lights are turned off, outside air starts flowing in after the desiccant 8 begins to cool down, and the inflow amount is also averaged and the inflow time is long. More effective in removing moisture.

In the above embodiment, the container 4 was made separately, and the housing (reflector) penetrated and held it, but
As shown in FIG. 4, the container portion 4' may be formed integrally with the housing 1. Furthermore, the filter 7 disposed at the end of the container 4 is for preventing the desiccant 8 from flowing out and water, dust, etc. from flowing in while maintaining air permeability. It may be made of the same material as the breathable porous resin membrane. However, in this case, the condition is that the air permeability is higher than that of the inner side.

[Effect of idea]

As described above, according to the present invention, a breathable porous resin membrane (layer) is provided at the end of the container containing the desiccant inside the housing, and the outflow amount is made convenient for dehumidification. It can be expected to have a sufficient dehumidification effect, and with ventilation holes, it can pass the FMVSS (Federal Motor Vehicle Safety Standards) humidity test. In addition, vented headlamps have less internal pressure rise than fully enclosed headlamps, which reduces the pressure resistance of lamp components, significantly improving reliability, reducing costs, reducing weight, and increasing design flexibility. It can be increased.
Furthermore, the structure of the ventilation hole is simple and the number of parts is small.
It has the advantage of being compact in shape.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing an embodiment of an automobile headlamp according to the present invention, Fig. 2 is a characteristic diagram showing the relationship between the on/off cycle and the humidity inside the headlamp, and Fig. 3 is a total flow rate of the air vent. FIG. 4 is a sectional view showing another embodiment of the present invention, and FIGS. 5 to 7 are sectional views showing a conventional example. 1...Housing, 2...Lens, 3...Bulb, 4...Container, 4a...Small hole, 5...L-shaped tube,
5a...Small pores, 6...Breathable porous resin membrane, 7...
...Filter, 8...Drying agent.

Claims (1)

[Scope of utility model registration request] In an automobile headlamp, a desiccant container is provided inside and outside the housing, and the desiccant is stored inside and outside the container, and among the small holes for ventilation formed at both ends of the container, the small hole on the inside of the housing is A porous resin membrane with air permeability is placed between the housing and the desiccant, and a porous resin membrane with air permeability is placed between the small holes on the outside of the housing and the desiccant, which has higher air permeability than the porous resin membrane and prevents desiccant from flowing out and water. , a filter is installed to prevent the inflow of dust, etc., and the time change in the amount of air flowing out of the housing when the headlamp is on and the amount of air flowing into the housing when the headlamp is turned off is monitored over a certain period of time. A headlamp for an automobile with a ventilation hole, characterized in that the headlamp reaches a peak after that and then gradually decreases.