Dehumidifying unit and vehicular lighting fixture

Abstract

To provide a dehumidifying unit which is suitable for a vehicular lighting fixture and which has achieved energy saving.SOLUTION: A dehumidifying unit 100 includes: a dehumidifying agent 102 which can be regenerated by heating; a housing 104 which has a first opening 112 and which surrounds the dehumidifying agent 102; a heater 106 which actuates so as to heat the dehumidifying agent 102; a thermal deformation element 108 which is formed by a shape memory alloy, and which deforms from a first shape to a second shape by heating of the heater 106; and a valve body 110 connected to the housing 104 by the thermal deformation element 108, and which moves with respect to the housing 104 in such a manner that, when the thermal deformation element 108 is in the first shape, the first opening 112 is opened, and when the thermal deformation element 108 is in the second shape, the first opening 112 is closed.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a dehumidifying unit, and more particularly to a dehumidifying unit suitable for dehumidifying the internal space of a vehicle lamp mounted on a vehicle such as an automobile. The present invention also relates to a vehicle lamp including the dehumidifying unit.

Background Art

[0002] When condensation occurs on the optical element inside the headlamp of a vehicle, there is concern that the lighting performance may be affected. Therefore, as a countermeasure against condensation, it has been proposed to attach a device incorporating a dehumidifying agent to the housing of the headlamp and dehumidify the inside of the housing with this dehumidifying agent (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The above-described dehumidifying device includes a shutter and a heater. By closing the shutter, the dehumidifying agent is separated from the housing of the headlamp. The dehumidifying agent is heated with a heater to release water vapor from the dehumidifying agent and exhaust it from the device to the outside. In this way, the dehumidifying agent is regenerated, and by opening the shutter again, the device can dehumidify the housing again. The opening and closing of the shutter are driven by an electric motor such as a DC motor or an electromagnet. Mounting such a dedicated drive source for the shutter on the device may cause an increase in power consumption and an increase in the size of the device.

[0005] The present invention has been made in view of such circumstances, and an exemplary object of one aspect thereof is to reduce power consumption of a dehumidifying unit suitable for a vehicle lamp.

Means for Solving the Problems

[0006] To solve the above problems, a dehumidifying unit according to an aspect of the present invention includes a dehumidifying agent that can be regenerated by heating, a housing having a first opening and surrounding the dehumidifying agent, a heater that operates to heat the dehumidifying agent, a thermal deformation element formed of a shape memory alloy that deforms from a first shape to a second shape by heating of the heater, and a valve body connected to the housing by the thermal deformation element, the valve body moving with respect to the housing such that the first opening is opened when the thermal deformation element is in the first shape and the first opening is closed when the thermal deformation element is in the second shape.

[0007] According to this aspect, the dehumidifying unit can move the valve body by utilizing the shape change of the thermal deformation element due to a temperature change, open and close the first opening of the housing, and perform a moisture release operation or a dehumidifying operation through the first opening. The dehumidifying unit is provided with a heater to enable regeneration of the dehumidifying agent by heating, and the thermal deformation element deforms by heating of the heater. Different from existing dehumidifying devices, the dehumidifying unit does not require a dedicated drive source such as an electric motor for moving the valve body. Since a part of the heat generated by the heater for heating the dehumidifying agent can be used to move the valve body, the dehumidifying unit can suppress power consumption compared to existing devices. By not having a dedicated drive source, miniaturization and weight reduction of the dehumidifying unit are also possible.

[0008] The thermal deformation element may include a wire of a shape memory alloy having a first length in the first shape and a second length different from the first length in the second shape. The wire is fixed to the housing at a first end of the wire and fixed to the valve body at a second end of the wire, and may be attached to the valve body in an arc shape around the rotation axis of the valve body between the first end and the second end. The valve body may rotate around the rotation axis with respect to the housing such that the first opening is opened when the wire has the first length and the first opening is closed when the wire has the second length. In this way, by utilizing the length change of the wire formed of the shape memory alloy due to a temperature change, the valve body can be rotated and the first opening can be opened and closed.

[0009] The valve body may engage with the housing such that it moves in the direction of the rotation axis as it rotates about the rotation axis relative to the housing. The first opening may be disposed on the first side of the housing in the direction of the rotation axis. When the wire has a first length, the valve body is located on the second side of the housing opposite the first side in the direction of the rotation axis so as to open the first opening, and when the wire has a second length, the valve body may be located on the first side in the direction of the rotation axis so as to close the first opening. In this way, by utilizing the change in length of the wire formed of a shape memory alloy due to temperature change, the valve body can be rotated and moved in the direction of the rotation axis to open and close the first opening.

[0010] The thermal deformation element may deform from the second shape to the first shape by cooling. In this way, the deformation of the thermal deformation element due to heating by the heater can be returned to the original shape by cooling.

[0011] The housing may further have a second opening different from the first opening. The first opening is disposed in the housing so as to communicate with the device to be dehumidified by the dehumidification unit when the housing is attached to the device to be dehumidified, and the second opening may be disposed in the housing so as to communicate with the surrounding environment when the housing is attached to the device to be dehumidified. The valve body may move relative to the housing so as to close the second opening when the thermal deformation element is in the first shape and open the second opening when the thermal deformation element is in the second shape.

[0012] In this way, the dehumidifying unit operates to open the first opening and close the second opening when the heater is turned off and the thermal deformation element is in the first shape, while closing the first opening and opening the second opening when the heater is turned on and the thermal deformation element is in the second shape. That is, when the first opening is open, the heater is off and the dehumidifying agent is not heated by the heater. When the second opening is open, the dehumidifying agent is heated by the heater. Therefore, the dehumidifying unit functions the first opening as an intake port from the device to be dehumidified to the dehumidifying unit, takes in air from the device to be dehumidified into the dehumidifying unit through the first opening, and can dehumidify the water vapor in the air with the dehumidifying agent. Further, the dehumidifying unit functions the second opening as an outlet from the dehumidifying unit to the surrounding environment, and can exhaust the water vapor released from the dehumidifying agent by heating to the outside through the second opening from the dehumidifying unit.

[0013] Another aspect of the present invention relates to a vehicle lamp. The vehicle lamp includes the dehumidifying unit of the above-described aspect. In this way, the vehicle lamp can be dehumidified using the dehumidifying unit.

Advantages of the Invention

[0014] According to the present invention, it is possible to provide a power-saving dehumidifying unit suitable for a vehicle lamp.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Embodiments for Carrying Out the Invention

[0016] Hereinafter, the present invention will be described with reference to the drawings based on preferred embodiments. The embodiments are illustrative and not restrictive of the invention, and all features and combinations thereof described in the embodiments are not necessarily essential to the invention. The same or equivalent components, members, and processes shown in each drawing are denoted by the same reference numerals, and repeated explanations are omitted as appropriate. Also, the scales and shapes of the respective parts shown in each figure are set for convenience in order to facilitate the explanation, and are not to be construed restrictively unless otherwise specified. In addition, terms such as "first" and "second" used in this specification or the claims do not represent any order or importance, but are for distinguishing one configuration from another. Also, in each drawing, some members that are not important for explaining the embodiment are omitted from the display.

[0017] FIG. 1 is a schematic front view of a vehicle lamp 10 according to an embodiment. FIG. 2 is a schematic view showing a vertical cross-section along line A-A of the vehicle lamp 10 shown in FIG. 1.

[0018] In this embodiment, the vehicle lamp 10 is a vehicle headlamp device having a pair of headlamp units arranged on the left and right in front of the vehicle. Since the pair of headlamp units have a substantially symmetric structure and are substantially the same in configuration, FIG. 1 shows the vehicle lamp located on the left side as viewed from the front of the vehicle body. Therefore, in FIG. 1, the left side corresponds to the outer side in the vehicle width direction, and the right side corresponds to the inner side in the vehicle width direction.

[0019] The vehicle lamp 10 includes a lamp body 12 having a front opening 13, and a light-transmitting cover 14 attached to the front side of the lamp body 12 so as to cover the front opening 13 that opens to the front side of the vehicle. The light-transmitting cover 14 is often also called an outer lens. The lamp body 12 is configured to be attachable to the vehicle body, and the light-transmitting cover 14 is attached to the vehicle body via the lamp body 12. The lamp housing 16 is formed by combining the lamp body 12 and the light-transmitting cover 14, and the internal space of the lamp housing 16 is formed as a lamp chamber 17. The lamp body 12 is formed of an appropriate synthetic resin material such as a general-purpose resin material. The light-transmitting cover 14 is formed of an appropriate light-transmitting material such as a synthetic resin material having light-transmitting properties or glass.

[0020] The vehicle lamp 10 includes a dehumidifying unit 100, which will be described in detail later. The dehumidifying unit 100 is attached to the outside of the vehicle lamp 10 so as to face the surrounding environment 11 of the vehicle lamp 10. As an example, the dehumidifying unit 100 is attached to, for example, the back surface of the vehicle lamp 10. An opening 12a for attaching the dehumidifying unit 100 is formed on the back surface of the lamp body 12, and the dehumidifying unit 100 is attached to the lamp body 12 so as to close the opening 12a so as to maintain the airtightness of the lamp chamber 17. Note that the dehumidifying unit 100 may be attached to other locations of the vehicle lamp 10, such as the bottom surface of the lamp body 12.

[0021] In addition, the vehicle lamp 10 includes at least one optical unit 18 disposed in the lamp chamber 17, for example, a headlamp unit. That is, the optical unit 18 functions as a headlamp. As an example, the optical unit 18 may be configured to provide at least one of three functions: low beam, high beam, and adaptive high beam that forms an optimal light distribution pattern according to the vehicle surrounding situation.

[0022] The vehicle lamp 10 may include at least one additional optical unit, in this example, a first marker lamp unit 20a and a second marker lamp unit 20b. Similar to the optical unit 18, these additional units are also disposed in the lamp chamber 17. As a non-limiting example, as shown in FIG. 1, the first marker lamp unit 20a may be disposed above the optical unit 18, and the second marker lamp unit 20b may be disposed inside the optical unit 18. Further, a further optical unit, for example, a third marker lamp unit (not shown), may be disposed below the optical unit 18.

[0023] By including a plurality of optical units, the vehicle lamp 10 can provide a plurality of different lamp functions. For example, the first marker lamp unit 20a may be an optical unit that functions as a clearance lamp and / or a daytime running lamp, and the second marker lamp unit 20b may be an optical unit that functions as a front turn signal lamp.

[0024] The optical unit 18 is supported by the lamp body 12 via a known swing mechanism and is configured to be adjustable in the direction of the optical axis extending in the longitudinal direction of the vehicle in the vertical direction and / or the horizontal direction. The first marker lamp unit 20a and the second marker lamp unit 20b are fixedly supported with respect to the lamp body 12.

[0025] As shown in FIG. 2, the optical unit 18 includes a light source 22 and at least one optical member (e.g., a reflector 24 and a projection lens 26) for directing the light emitted from the light source 22 toward the transparent cover 14. The optical unit 18 also includes a light-emitting element mounting portion 28 having a heat dissipation portion 30.

[0026] The light source 22 includes a semiconductor light-emitting element such as a light-emitting diode (LED) or other light-emitting element 22a, and a substrate 22b such as a printed circuit board on which the light-emitting element 22a is mounted. As an exemplary arrangement, the light source 22 is mounted on the light-emitting element mounting portion 28 with the light-emitting surface of the light-emitting element 22a directed upward of the vehicle and the optical axis of the light-emitting element 22a extending substantially in the vertical direction of the vehicle.

[0027] The reflector 24 is disposed above the light source 22 so as to reflect the emitted light of the light source 22 toward the projection lens 26. The reflector 24 is a reflecting member having a reflecting surface formed on the inner surface facing the light source 22, and the reflecting surface is formed of, for example, a part of a rotational ellipsoidal surface or other appropriate curved surface. The projection lens 26 is disposed in front of the light source 22 so as to project the reflected light from the reflector 24 in front of the lamp unit. As an example, the projection lens 26 is a plano-convex aspherical lens having a convex front surface and a flat rear surface, and is formed of an appropriate light-transmissive material such as a synthetic resin material or glass having light-transmissivity.

[0028] The light emitted from the light-emitting element 22a of the light source 22 is reflected by the reflecting surface of the reflector 24 and directed toward the projection lens 26. The light is emitted outside the vehicle lamp unit 10 through the projection lens 26 and the transparent cover 14.

[0029] The light-emitting element mounting portion 28 provides a support surface for supporting the light source 22 and is integrally formed with the heat radiating portion 30. The heat radiating portion 30 has a plurality of heat radiating fins extending rearward from the light-emitting element mounting portion 28. Each heat radiating fin may be parallel to the vertical plane. The light-emitting element mounting portion 28 and the heat radiating portion 30 also function as a heat radiating member for radiating the heat generated by the light source 22 and are also called a heat sink. The light-emitting element mounting portion 28 and the heat radiating portion 30 are formed of a metal material having a high thermal conductivity such as aluminum or an aluminum alloy, and are manufactured by, for example, a die casting method.

[0030] In addition, the light-emitting element mounting portion 28 also serves as a support member for supporting the optical member of the optical unit 18. The optical member may be directly fixed to the light-emitting element mounting portion 28 or may be attached to the light-emitting element mounting portion 28 via an appropriate attachment member such as a bracket. For example, the reflector 24 may be directly fixed to the light-emitting element mounting portion 28 by an appropriate fixing method such as screwing. The projection lens 26 may be attached to the light-emitting element mounting portion 28 via the attachment member 32.

[0031] In this embodiment, as an example, the optical unit 18 may be an optical unit for a so-called projector type headlamp also referred to as a so-called PES (Polyellipsoid System) type. The optical unit 18 may be an optical unit for other types of headlamps such as a parabolic headlamp or a so-called blade scan type headlamp that enables adaptive light distribution control using a rapidly rotating reflector.

[0032] The vehicle lamp 10 further includes a control device 40 that controls the vehicle lamp 10, also referred to as a lamp ECU (Electronic Control Unit). Under the control of a host controller (also referred to as a vehicle ECU) that is disposed outside the vehicle lamp 10 and comprehensively controls the entire vehicle or a part thereof, the control device 40 controls an optical unit 18, a first marker lamp unit 20a, and a second marker lamp unit 20b. The control device 40 acquires vehicle information necessary for controlling the vehicle lamp 10 from the vehicle ECU and controls the operations (e.g., on / off, light quantity, etc.) of each optical unit based on this information. Not only these optical units, but the control device 40 may also control the operation of the dehumidifying unit 100 based on the vehicle information from the vehicle ECU. As an exemplary arrangement, the control device 40 may be disposed within the lamp chamber 17 and below the optical unit 18.

[0033] FIG. 3 is a schematic exploded perspective view showing a first exemplary dehumidifying unit 100 according to an embodiment. FIGS. 4 and 5 are schematic cross-sectional views showing the first exemplary dehumidifying unit 100 according to an embodiment. FIGS. 6 and 7 are schematic plan views showing the first exemplary dehumidifying unit 100 according to an embodiment.

[0034] The dehumidifying unit 100 described with reference to FIGS. 3 to 7 can be installed in the vehicle lamp 10 shown in FIGS. 1 and 2. FIGS. 4 and 6 show the dehumidifying unit 100 during the dehumidifying operation, and FIGS. 5 and 7 show the dehumidifying unit 100 during the moisture release operation. FIGS. 6 and 7 show a schematic plan view of the dehumidifying unit 100 with the first case 104a of the housing 104 removed from the dehumidifying unit 100 in order to better understand the movement of the thermal deformation element 108 and the valve body 110 within the dehumidifying unit 100.

[0035] The dehumidifying unit 100 includes a dehumidifying agent 102, a housing 104, a heater 106, a thermal deformation element 108, and a valve body 110.

[0036] The dehumidifying agent 102 contains any material that can absorb water vapor from the air in the space, such as silica gel, etc., thereby reducing the humidity of the space. Also, the dehumidifying agent 102 can be regenerated by heating. That is, when the dehumidifying agent 102 absorbs a certain amount of water vapor, its absorption capacity becomes saturated. Therefore, the dehumidifying agent 102 can release the absorbed water vapor from the dehumidifying agent 102 by heating, thereby restoring the water vapor absorption capacity and enabling reuse.

[0037] The housing 104 is a container that surrounds the dehumidifying agent 102 and has a first opening 112 and a second opening 114 that is different from the first opening 112. The first opening 112 is formed in the housing 104 as an air inlet to the dehumidifying agent 102, and the second opening 114 is formed in the housing 104 as an air outlet for the air containing the water vapor released from the dehumidifying agent 102 to the surrounding environment 11 when the dehumidifying agent 102 is regenerated.

[0038] The housing 104 is designed to be attachable to the dehumidification target device so as to maintain the airtightness of the internal space of the dehumidification target device by the dehumidification unit 100. In this embodiment, the housing 104 is designed to be attachable to the opening 12a of the lamp body 12 so as to maintain the airtightness of the lamp chamber 17 of the vehicle lamp 10. Therefore, the first opening 112 is arranged in the housing 104 so as to communicate with the lamp chamber 17 when the housing 104 is attached to the opening 12a of the lamp body 12. The second opening 114 is arranged in the housing 104 so as to communicate with the surrounding environment 11 when the housing 104 is attached to the opening 12a of the lamp body 12.

[0039] As an exemplary shape, the housing 104 has a cylindrical shape centered on the rotation axis C of the valve body 110. In this example, the length of the housing 104 in the direction of the rotation axis C is shorter than the diameter of the housing 104, and the housing 104 has a disk shape. The housing 104 is formed of a synthetic resin material such as a general-purpose resin material, or other appropriate materials.

[0040] The housing 104 may be composed of a plurality of housing components that can be assembled to each other so as to maintain airtightness inside. In this embodiment, it includes a first case 104a and a second case 104b. The second case 104b is the cylindrical so-called main body of the housing 104 that houses the components of the dehumidification unit 100 such as the dehumidifying agent 102, the heater 106, the thermal deformation element 108, and the valve body 110. The first case 104a is the disc-shaped so-called lid that closes the second case 104b. When the dehumidification unit 100 is attached to the vehicle lamp 10, the first case 104a is attached to the lamp body 12, and the second case 104b is exposed to the surrounding environment 11.

[0041] The first opening 112 is disposed on the first side of the housing 104, and the second opening 114 is disposed on the second side of the housing 104 on the side opposite to the first side in the direction of the rotation axis C. For example, the first opening 112 is formed in the first case 104a, and the second opening 114 is formed in the second case 104b. The first opening 112 and the second opening 114 are formed on opposite sides of the housing 104.

[0042] The first opening 112 may be one or more holes formed in the first case 104a. In this example, as shown in FIG. 3, four holes are evenly provided around the rotation axis C of the valve body 110 at the center of the first case 104a. The dehumidification unit 100 may be provided with a waterproof and moisture-permeable sheet 118 such as Gore-Tex (registered trademark) so as to cover the first opening 112 on the first case 104a. The second opening 114 may be one or more holes formed in the second case 104b. In this example, as shown in FIG. 3, a plurality of holes are evenly provided around the rotation axis C of the valve body 110 at the outer peripheral portion of the bottom surface of the second case 104b.

[0043] The heater 106 is configured to heat the dehumidifying agent 102. The heater 106 may be a resistance heating type heater including a resistance element that generates Joule heat when an electric current flows, such as a PTC thermistor, for example. The heater 106 may have a thin plate shape as illustrated. Alternatively, the heater 106 may be other electric heaters or heaters of other types. The heater 106 may be powered from the vehicle lamp 10 through electrical wiring (not shown).

[0044] When the heater 106 is not operating (i.e., when the heater 106 is off), the dehumidifying agent 102 can absorb water vapor. When the heater 106 is operating (i.e., when the heater 106 is on), the dehumidifying agent 102 can release water vapor by heating of the heater 106.

[0045] In order to effectively transfer the heat generated by the heater 106 to the dehumidifying agent 102 and the thermal deformation element 108, the dehumidifying unit 100 is provided with a heat transfer member 120. The heat transfer member 120 can also be called a heat sink for diffusing the heat from the heater 106 inside the dehumidifying unit 100. The heat transfer member 120 is formed of a material having a high thermal conductivity, such as a metal material, for example.

[0046] As an example, the heat transfer member 120 may include a first heat transfer plate 120a that contacts one surface of the heater 106 and a second heat transfer plate 120b that contacts the surface of the heater 106 opposite thereto. The first heat transfer plate 120a also contacts the dehumidifying agent 102 and thermally connects the heater 106 to the dehumidifying agent 102. The first heat transfer plate 120a is disposed between the valve body 110 and the heater 106 together with the dehumidifying agent 102, and the second heat transfer plate 120b is disposed between the heater 106 and the second case 104b.

[0047] The dehumidifying agent 102, the heater 106, and the heat transfer member 120 are arranged between the bottom surface of the second case 104b and the valve body 110 in the direction of the rotation axis C. Further, the dehumidifying agent 102, the heater 106, and the heat transfer member 120 are arranged at the central portion of the bottom surface of the second case 104b, that is, inside the second opening 114 in the second case 104b, in the radial direction centered on the rotation axis C.

[0048] The thermal deformation element 108 is formed of a shape memory alloy and is designed to deform from the first shape to the second shape by heating of the heater 106 and to deform from the second shape to the first shape by cooling. As an exemplary configuration, it is a wire of a shape memory alloy. Therefore, hereinafter, the thermal deformation element 108 is also referred to as an SMA (Shape Memory Alloy) wire. The SMA wire has a first length in the first shape before heating by the heater 106 and has a second length different from the first length in the second shape after heating by the heater 106.

[0049] The second length may be shorter than the first length. In this case, when the SMA wire is heated to a transformation temperature or a temperature exceeding it in the housing 104 by the heat generated by the heater 106, it contracts in the length direction. Further, when the heater 106 is turned off and cooled, the SMA wire elongates in the length direction and is restored to the length before heating by the heater 106.

[0050] The valve body 110 is connected to the housing 104 by the thermal deformation element 108. As shown in FIG. 6, the SMA wire is fixed to the housing 104 at the first end 108a of the SMA wire, fixed to the valve body 110 at the second end 108d of the SMA wire, and is attached to the valve body 110 in an arc shape around the rotation axis C of the valve body 110 between the first end 108a and the second end 108d. Therefore, the valve body 110 can rotate around the rotation axis C due to the deformation of the thermal deformation element 108 (that is, the expansion and contraction of the SMA wire).

[0051] More specifically, the SMA wire includes a straight portion 108b having a first end 108a and an arc portion 108c having a second end 108d. The first end 108a of the SMA wire is fixed to the outer peripheral portion of the second case 104b of the housing 104. The straight portion 108b of the SMA wire extends from the first end 108a to the arc portion 108c. The arc portion 108c of the SMA wire forms an arc with a central angle of approximately 270 degrees as an example, and is attached to the outer peripheral edge of the central portion 110a of the valve body 110 so that its center coincides with the rotation axis C of the valve body 110.

[0052] The valve body 110 is configured to move relative to the housing 104 so as to open the first opening 112 when the thermal deformation element 108 is in the first shape (i.e., when the SMA wire is in the first length), and to close the first opening 112 when the thermal deformation element 108 is in the second shape (i.e., when the SMA wire is in the second length). Further, the valve body 110 is configured to move relative to the housing 104 so as to close the second opening 114 when the thermal deformation element 108 is in the first shape, and to open the second opening 114 when the thermal deformation element 108 is in the second shape.

[0053] In this embodiment, the movement of the valve body 110 relative to the housing 104 by the thermal deformation element 108 is the rotation of the valve body 110 around the rotation axis C. When the SMA wire contracts, when viewed from the first case 104a side toward the second case 104b, the valve body 110 rotates counterclockwise from the initial state shown in FIG. 6 by an angle corresponding to the contraction amount of the SMA wire, as indicated by the arrow 142 in FIG. 7. Conversely, when the SMA wire extends, the valve body 110 rotates clockwise, as indicated by the arrow 143 in FIG. 6, and returns from the state of FIG. 7 to the state of FIG. 6.

[0054] The valve body 110 is engaged with the housing 104 so as to move in the direction of the rotation axis C as it rotates about the rotation axis C with respect to the housing 104. When the SMA wire has a first length, the valve body 110 is located on the second side (i.e., the second case 104b side) of the housing 104, which is opposite to the first side (i.e., the first case 104a side) of the housing 104 in the direction of the rotation axis C so as to open the first opening 112 and close the second opening 114. Also, when the SMA wire has a second length, the valve body 110 is located on the first side of the housing 104 in the direction of the rotation axis C so as to close the first opening 112 and open the second opening 114.

[0055] Therefore, as shown in FIG. 3, a cam-shaped portion 150 is formed on the housing 104. The cam-shaped portion 150 includes a first inclined surface that rises from the surface of the housing 104 facing the valve body 110 toward the valve body 110. As an example, the first inclined surface is provided at the outer peripheral portion of the bottom surface of the second case 104b, for example, at the same radial position as the second opening 114 around the rotation axis C. When viewed from the first case 104a side toward the second case 104b, the first inclined surface is inclined with respect to the bottom surface of the second case 104b such that its height increases as it advances counterclockwise around the rotation axis C.

[0056] A follower-shaped portion 152 that follows the cam-shaped portion 150 is formed on the valve body 110. The follower-shaped portion 152 has a second inclined surface that contacts the first inclined surface of the cam-shaped portion 150 at a location on the valve body 110 facing the cam-shaped portion 150 of the housing 104. As an example, the second inclined surface is formed on the surface of the valve body 110 on the second case 104b side and is inclined at the same angle as the first inclined surface with respect to the bottom surface of the second case 104b. Since the cam-shaped portion 150 is provided at the outer peripheral portion of the second case 104b, correspondingly, the follower-shaped portion 152 is provided at the outer peripheral portion 110b of the valve body 110.

[0057] A plurality of cam-shaped portions 150 and follower-shaped portions 152 may be provided respectively. For example, two cam-shaped portions 150 may be provided on both sides of the rotation axis C on the outer peripheral portion of the second case 104b, and correspondingly, two follower-shaped portions 152 may be provided on both sides of the rotation axis C on the outer peripheral portion 110b of the valve body 110.

[0058] Therefore, when the valve body 110 rotates around the rotation axis C with respect to the housing 104, the second inclined surface of the follower-shaped portion 152 of the valve body 110 slides on the first inclined surface of the cam-shaped portion 150 of the housing 104, whereby the valve body 110 moves in the direction of the rotation axis C with respect to the housing 104. When viewed from the first case 104a side toward the second case 104b, when the valve body 110 rotates counterclockwise around the rotation axis C, the valve body 110 moves away from the second case 104b and approaches the first case 104a in the direction of the rotation axis C as indicated by the arrow 144 in FIG. 5. Conversely, when the valve body 110 rotates clockwise around the rotation axis C, the valve body 110 moves toward the second case 104b in the direction of the rotation axis C as indicated by the arrow 145 in FIG. 4.

[0059] As an alternative, the cam-shaped portion 150 may be formed in the first case 104a. In this case, the follower-shaped portion 152 may be formed on the surface of the valve body 110 on the side of the first case 104a.

[0060] As an exemplary configuration of the valve body 110, the valve body 110 is configured to open and close the first opening 112 at its central portion 110a and open and close the second opening 114 at its outer peripheral portion 110b. The central portion 110a is arranged closer to the first case 104a than the outer peripheral portion 110b, and the outer peripheral portion 110b is arranged closer to the second case 104b than the central portion 110a, so that the central portion 110a and the outer peripheral portion 110b are connected to each other in the direction of the rotation axis C. The outer peripheral edge of the central portion 110a is connected to the inner peripheral edge of the outer peripheral portion 110b.

[0061] As shown in FIGS. 4 and 5, the central portion 110a of the valve body 110 is provided with a guide surface 154 that extends parallel to the rotation axis C toward the first case 104a around the rotation axis C. A central recess 156 is formed in the central portion 110a of the valve body 110 radially inward of the guide surface 154, and a communication hole 158 is formed radially outward of the guide surface 154. The communication hole 158 may be one or more holes formed in the valve body 110. In this example, as shown in FIG. 3, six holes are evenly provided around the rotation axis C.

[0062] Also, as shown in FIGS. 4 and 5, a partition wall 160 is formed in the first case 104a so as to surround the first opening 112. The partition wall 160 has a cylindrical shape and extends parallel to the rotation axis C from the first case 104a toward the central portion 110a of the valve body 110 at the center of the first case 104a. The partition wall 160 is in contact with the guide surface 154 on its outer peripheral surface.

[0063] When the valve body 110 is separated from the first case 104a in the direction of the rotation axis C, as shown in FIG. 4, a first space 162a on the first case 104a side and a second space 162b on the second case 104b side communicate with each other through the communication hole 158 with respect to the valve body 110. In this way, the valve body 110 can open the first opening 112.

[0064] When the valve body 110 moves in the direction of the rotation axis C and approaches the first case 104a, the guide surface 154 slides in the direction of the rotation axis C along the partition wall 160, and the movement of the valve body 110 is guided by the partition wall 160. When the valve body 110 approaches the first case 104a further, the communication hole 158 of the valve body 110 is blocked. That is, as shown in FIG. 5, the partition wall 160 fits into the central recess 156 of the valve body 110, and the communication between the first space 162a and the second space 162b through the communication hole 158 is blocked. In this way, the valve body 110 can close the first opening 112.

[0065] As shown in FIG. 4, the outer peripheral portion 110b of the valve body 110 contacts the bottom surface of the second case 104b, thereby closing the second opening 114. When the valve body 110 moves in the direction of the rotation axis C while rotating around the rotation axis C, the outer peripheral portion 110b of the valve body 110 slides along the inner peripheral surface of the second case 104b. The valve body 110 moves toward the first case 104a while being guided by the second case 104b. Thus, as shown in FIG. 5, when the outer peripheral portion 110b of the valve body 110 separates from the bottom surface of the second case 104b, the valve body 110 can open the second opening 114.

[0066] Further, the dehumidifying unit 100 includes an elastic body 164 that biases the valve body 110 toward the second opening 114. The elastic body 164 is, for example, a spring that can expand and contract in the direction of the rotation axis C of the valve body 110, and is disposed in a compressed state between the first case 104a and the valve body 110. The elastic body 164 is disposed inside the partition wall 160 of the first case 104a on the central concave portion 156 of the valve body 110. As shown in FIG. 4, when the valve body 110 closes the second opening 114, the elastic body 164 presses the valve body 110 toward the second opening 114 by an elastic restoring force. This helps the valve body 110 to seal the second opening 114.

[0067] The valve body 110 is formed of, for example, a synthetic resin material such as a general-purpose resin material, or other appropriate materials. The elastic body 164 is formed of, for example, a metal material such as stainless steel, or other appropriate materials.

[0068] Next, the operation of the dehumidifying unit 100 will be described. When the heater 106 is turned off, the valve body 110 is in its initial position. At this time, as shown in FIG. 4, the valve body 110 opens the first opening 112 and closes the second opening 114. Since the first opening 112 is open, the air containing water vapor from the lamp chamber 17 of the vehicle lamp 10 is taken into the housing 104 through the first opening 112. The air flowing into the housing 104 can contact the dehumidifying agent 102 through the communication hole 158 of the valve body 110. At this time, since the heater 106 is not operating, the dehumidifying agent 102 is not heated by the heater 106. The dehumidifying agent 102 can absorb water vapor from the air. In this way, the dehumidifying unit 100 can perform the dehumidifying operation of the vehicle lamp 10. The dehumidifying operation is typically performed when the vehicle engine is stopped. For the sake of understanding, in FIGS. 2 and 4, the air flow in the dehumidifying operation is schematically shown by the dashed arrows.

[0069] On the other hand, when the heater 106 is activated, the inside of the housing 104 is heated, and the thermal deformation element 108 deforms from the first shape to the second shape. That is, the SMA wire contracts from the first length to the second length, and as schematically shown by the arrow 142 in FIG. 7, the valve body 110 is rotated about the rotation axis C. While rotating, the valve body 110 moves away from the second case 104b and approaches the first case 104a in the direction of the rotation axis C, as schematically shown by the arrow 144 in FIG. 5. Thus, as shown in FIG. 5, the valve body 110 closes the first opening 112 and opens the second opening 114.

[0070] The heater 106 heats not only the thermal deformation element 108 but also the dehumidifying agent 102. The water vapor absorbed by the dehumidifying agent 102 during the dehumidifying operation is released from the dehumidifying agent 102 by heating. The released water vapor is discharged to the outside of the dehumidifying unit 100, that is, the surrounding environment 11, through the second opening 114. In this way, the dehumidifying unit 100 can perform the moisture release operation. The moisture release operation is typically performed when the vehicle engine is running. For the sake of understanding, in FIGS. 2 and 5, the air flow in the moisture release operation is schematically shown by the solid arrows.

[0071] When the heater 106 is switched off, the dehumidifying unit 100 is naturally cooled. By the cooling, the thermal deformation element 108 deforms from the second shape to the first shape. That is, the SMA wire extends from the second length to the first length. The valve body 110 moves toward the second case 104b in the direction of the rotation axis C as schematically shown by an arrow 146 in FIG. 4 while rotating around the rotation axis C as schematically shown by an arrow 143 in FIG. 6. Thus, the valve body 110 opens the first opening 112 and closes the second opening 114 again as shown in FIG. 4. The dehumidifying unit 100 can resume the dehumidifying operation of the vehicle lamp 10.

[0072] By repeating such dehumidifying operations and moisture releasing operations, the dehumidifying unit 100 can dehumidify the vehicle lamp 10. Thereby, generation of dew condensation in the vehicle lamp 10 can be prevented or the risk thereof can be reduced.

[0073] The dehumidifying unit 100 uses the heater 106 and the thermal deformation element 108 as driving sources for the valve body 110. Different from the existing dehumidifying devices described at the beginning of this document, the dehumidifying unit 100 does not require a dedicated driving source such as an electric motor for opening and closing the valve body 110. Since a part of the heat generated by the heater 106 for heating the desiccant 102 can be used to operate the valve body 110, the dehumidifying unit 100 can suppress power consumption compared with the existing devices. By not having a dedicated driving source, miniaturization and weight reduction of the dehumidifying unit 100 are also possible.

[0074] Figures 8 and 9 are schematic cross-sectional views showing a second exemplary dehumidifying unit 100 according to an embodiment. Figures 10 and 11 are schematic plan views showing the second exemplary dehumidifying unit 100 according to the embodiment. In Figures 8 and 10, the dehumidifying unit 100 during the dehumidifying operation is shown, and in Figures 9 and 11, the dehumidifying unit 100 during the moisture release operation is shown. In Figures 10 and 11, for better understanding of the movement of the thermal deformation element 108 and the valve body 110 within the dehumidifying unit 100, a schematic plan view of the dehumidifying unit 100 with the first case 104a removed from the second case 104b of the housing 104 is shown.

[0075] Similar to the first exemplary dehumidifying unit 100, the second exemplary dehumidifying unit 100 includes a desiccant 102, a housing 104, a heater 106, a thermal deformation element 108, and a valve body 110, and can be installed in the vehicle lamp 10 shown in Figures 1 and 2.

[0076] However, in the first exemplary dehumidifying unit 100, the valve body 110 rotates around the rotation axis C and moves in the direction of the rotation axis C to open and close the first opening 112 and the second opening 114 of the housing 104. In contrast, in the second exemplary dehumidifying unit 100, the valve body 110 rotates around the rotation axis C to open and close the first opening 112 and the second opening 114 of the housing 104. In the second exemplary dehumidifying unit 100, the valve body 110 does not move in the direction of the rotation axis C. Also, in the second exemplary dehumidifying unit 100, a torsion spring interposed between the housing 104 and the valve body 110 is used as the elastic body 164. Otherwise, the second exemplary dehumidifying unit 100 has the same configuration as the first exemplary dehumidifying unit 100 and operates in the same manner.

[0077] Therefore, when the heater 106 is turned off, as shown in FIG. 8, the valve body 110 opens the first opening 112 and closes the second opening 114. Since the first opening 112 is open, the air containing water vapor from the lamp chamber 17 of the vehicle lamp 10 is taken into the housing 104 through the first opening 112. The air flowing into the housing 104 can contact the dehumidifying agent 102 through the communication hole 158 of the valve body 110. At this time, since the heater 106 is not operating, the dehumidifying agent 102 is not heated by the heater 106. The dehumidifying agent 102 can absorb water vapor from the air. In this way, the dehumidifying unit 100 can perform the dehumidifying operation of the vehicle lamp 10.

[0078] On the other hand, when the heater 106 is activated, the interior of the housing 104 is heated, and the thermal deformation element 108 deforms from the first shape to the second shape. That is, the SMA wire contracts from the first length to the second length, and as indicated by the arrow 142 in FIG. 11, the valve body 110 is rotated about the rotation axis C. Thus, as shown in FIG. 9, the valve body 110 closes the first opening 112 and opens the second opening 114. The heater 106 heats not only the thermal deformation element 108 but also the dehumidifying agent 102. The water vapor absorbed by the dehumidifying agent 102 during the dehumidifying operation is released from the dehumidifying agent 102 by heating. The released water vapor is discharged to the outside of the dehumidifying unit 100, that is, the surrounding environment 11, through the second opening 114. In this way, the dehumidifying unit 100 can perform the moisture release operation.

[0079] When the heater 106 is switched off, the dehumidifying unit 100 is naturally cooled. By cooling, the thermal deformation element 108 deforms from the second shape to the first shape. That is, the SMA wire extends from the second length to the first length. The valve body 110 rotates about the rotation axis C as schematically indicated by the arrow 143 in FIG. 10. Thus, the valve body 110 again opens the first opening 112 and closes the second opening 114 as shown in FIG. 8. The dehumidifying unit 100 can resume the dehumidifying operation of the vehicle lamp 10.

[0080] Therefore, similar to the first exemplary dehumidifying unit 100, the second exemplary dehumidifying unit 100 can also dehumidify the vehicle lamp 10 by repeating such dehumidifying operation and dehumidifying operation. Thereby, the occurrence of condensation inside the vehicle lamp 10 can be prevented or the risk thereof can be reduced.

[0081] Further, since the dehumidifying unit 100 uses the heater 106 and the thermal deformation element 108 as the drive source of the valve body 110, the valve body 110 can be operated by using a part of the heat generated by the heater 106 to heat the dehumidifying agent 102. Since a dedicated drive source such as an electric motor for opening and closing the valve body 110 is not required, the dehumidifying unit 100 can be power-saving, downsized, and lightened.

[0082] The present invention is not limited to the above-described embodiments and modifications, and it is also possible to combine the embodiments and modifications, or to make further modifications such as various design changes based on the knowledge of those skilled in the art. Embodiments and modifications in which they are combined or further modified are also included in the scope of the present invention. The new embodiments generated by the above-described embodiments and modifications, and the combination of the above-described embodiments and modifications and the following modifications have the effects of the combined embodiments, modifications, and further modifications.

[0083] The above-described embodiment has been described by taking as an example the case where both the first opening 112 and the second opening 114 are opened and closed by one valve body 110, but the present invention is not limited thereto. The valve body may be provided for each opening. Therefore, the dehumidifying unit 100 may include a first valve body that opens and closes the first opening 112 and a second valve body that opens and closes the second opening 114.

[0084] The above-described embodiments have been described by taking the case where the dehumidifying unit 100 is attached to the vehicle lamp 10 as a vehicle headlamp device as an example. However, the present invention is not limited to this. The dehumidifying unit 100 according to the embodiments may be attached to other vehicle lamps, such as a marker lamp unit installed at the rear of the vehicle, and used for dehumidifying the inside thereof. Alternatively, the dehumidifying unit 100 according to the embodiments may be attached to in-vehicle devices or other devices and used for dehumidifying the inside thereof.

[0085] Based on the embodiments, the present invention has been described using specific terms. However, the embodiments merely show one aspect of the principle and application of the present invention. In the embodiments, many modifications and changes in arrangement are recognized without departing from the idea of the present invention defined in the claims.

Explanation of Reference Numerals

[0086] 10 Vehicle lamp, 11 Surrounding environment, 12a Opening, 100 Dehumidifying unit, 102 Desiccant, 104 Housing, 106 Heater, 108 Thermal deformation element, 108a First end, 108d Second end, 110 Valve body, 112 First opening, 114 Second opening, C Rotation axis.

Claims

1. A dehumidifying agent that can be regenerated by heating, A housing having a first opening and surrounding the dehumidifying agent, A heater that operates to heat the dehumidifying agent, A thermal deformation element formed of a shape memory alloy that deforms from a first shape to a second shape by heating of the heater, A valve body connected to the housing by the thermal deformation element, the valve body moving with respect to the housing so as to open the first opening when the thermal deformation element is in the first shape and close the first opening when the thermal deformation element is in the second shape. A dehumidifying unit characterized by comprising:

2. The thermal deformation element includes a wire of the shape memory alloy having a first length in the first shape and a second length different from the first length in the second shape, The wire is fixed to the housing at a first end of the wire and fixed to the valve body at a second end of the wire, and is mounted on the valve body in an arc shape around a rotation axis of the valve body between the first end and the second end, The dehumidifying unit according to claim 1, wherein the valve body rotates around the rotation axis with respect to the housing so as to open the first opening when the wire has the first length and close the first opening when the wire has the second length.

3. The valve body is engaged with the housing so as to move in the direction of the rotation axis as it rotates around the rotation axis with respect to the housing, The first opening is disposed on a first side of the housing in the direction of the rotation axis, The valve body is located on a second side of the housing opposite to the first side in the direction of the rotation axis so as to open the first opening when the wire has the first length, and is located on the first side in the direction of the rotation axis so as to close the first opening when the wire has the second length. The dehumidifying unit according to claim 2, characterized in that:

4. The dehumidifying unit according to any one of claims 1 to 3, wherein the thermal deformation element deforms from the second shape to the first shape by cooling.

5. The housing further has a second opening different from the first opening, The first opening is disposed in the housing so as to communicate with a dehumidification target device when the housing is attached to the dehumidification target device by the dehumidifying unit, The second opening is disposed in the housing so as to communicate with the surrounding environment when the housing is attached to the dehumidification target device. The valve body moves relative to the housing so as to close the second opening when the thermal deformation element is in the first shape and open the second opening when the thermal deformation element is in the second shape. The dehumidifying unit according to any one of claims 1 to 3.

6. A vehicle lamp comprising the dehumidifying unit according to any one of claims 1 to 3.

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