JP7501431B2 - Heated vehicle part and manufacturing method thereof - Google Patents

Description

The present invention relates to a vehicle part to be heated that is mounted on a vehicle.

Conventionally, a vehicle part to be heated that is arranged on a front bumper, a front grill, etc. is known (for example, Patent Document 1). The vehicle part to be heated described in Patent Document 1 is a radio wave transparent cover including a base material and a heating sheet. The radio wave transparent cover is arranged ahead of a millimeter wave radar device that transmits millimeter wave radio waves in the radio wave transmission direction. The heating sheet is arranged on the back side of the base material, specifically, arranged over the entire back surface of the base material. The heating sheet has a sheet portion formed of a resin material and a heater wire formed of a copper wire or the like. The heater wire is wired on the surface of the sheet portion that faces the back surface of the base material. When electricity is applied to the heater wire, the heater wire generates heat and heats the base material. Therefore, even when ice and snow adhere to the surface of the radio wave transparent cover, the ice and snow on the surface of the radio wave transparent cover can be melted by heat transfer to the base material, thereby ensuring the millimeter wave transparency of the radio wave transparent cover.

JP 2020-060406 A

Incidentally, in order to improve the heat transfer from the heating sheet to the front surface of the substrate, it is effective to thin the portion of the substrate corresponding to the region where the heating sheet is arranged. In this regard, in the above-mentioned heated vehicle component, the heating sheet is arranged over the entire back surface of the substrate, so it is necessary to thin the entire substrate in order to improve transfer. However, with this structure in which the entire substrate is thinned, although it is possible to ensure the heat transfer from the heating sheet to the substrate, the rigidity of the substrate is impaired.

The present invention was made in consideration of these points, and aims to provide a heated vehicle part that can increase the heat transfer from the heating sheet to the base material without compromising the rigidity of the base material.

One aspect of the present invention is a heated vehicle part that includes a plate-shaped base material that is permeable to millimeter wave radio waves and a sheet-shaped heating sheet that is placed on the back surface of the base material and heats the base material, the base material having a plate-shaped plate wall portion and a recess formed in a concave shape in a part of the entire back surface of the plate wall portion, and the heating sheet is placed in the recess.

With this configuration, a portion of the substrate is thinned and the heating sheet is placed in the thinned portion, improving heat transfer from the heating sheet to the substrate and increasing the rigidity of the substrate compared to a structure in which the entire substrate is thin. Therefore, it is possible to improve heat transfer from the heating sheet to the substrate without impairing the rigidity of the substrate.

1 is a perspective view of the front side of a vehicle on which a vehicle heating target part according to an embodiment of the present invention is mounted. 1 is a cross-sectional view of a heated vehicle part according to an embodiment of the present invention; 5A to 5C are diagrams for explaining a manufacturing method of a heating sheet provided in the heated vehicle part of the present embodiment. 4A to 4C are diagrams for explaining a manufacturing method of a heated vehicle component according to the present embodiment. FIG. 2 is a cross-sectional view of a modified embodiment of a heated vehicle part.

Below, a specific embodiment of a vehicle heated part according to the present invention will be described with reference to Figures 1 to 5.

In one embodiment, the vehicle heated part 1 is a part that is mounted on the vehicle 2 and heated, and is installed, for example, on the front bumper or rear bumper of the vehicle 2. Note that in this embodiment, the contents indicating the direction are based on the vehicle 2 on which the vehicle heated part 1 is mounted. For example, "right side" refers to the right side of the vehicle relative to the vehicle travel direction, and "left side" refers to the left side of the vehicle relative to the vehicle travel direction.

The vehicle part to be heated 1 is, for example, as shown in FIG. 1, a decorative part 1a such as an emblem or ornament, which is about 100 mm to 300 mm in size, a decorative part 1b such as a front grille or front panel, which is about 1300 mm to 1600 mm in size, or a bumper 1c itself, such as a front bumper or rear bumper.

The vehicle part 1 to be heated is a part that is permeable to millimeter-wave radio waves (frequency 30 GHz to 300 GHz) used in the millimeter-wave radar device 3 (see FIG. 2). The millimeter-wave radar device 3 transmits millimeter-wave radio waves outside the vehicle (for example, to the front of the vehicle) and receives those transmitted radio waves that are reflected by objects outside the vehicle. The millimeter-wave radar device 3 detects objects outside the vehicle based on the relationship between the time difference and strength between the transmitted and received radio waves, and detects the relative distance and relative speed between the vehicle 2 and the object outside the vehicle.

The vehicle part to be heated 1 is disposed ahead of the millimeter wave radar device 3 in the radio wave transmission direction (e.g., in front of the vehicle). Hereinafter, the vehicle part to be heated 1 is assumed to be disposed on the front side of the vehicle 2 and in front of the millimeter wave radar device 3. The vehicle part to be heated 1 includes a base material 10 and a heating sheet 20.

The substrate 10 is a plate-shaped component that forms the framework of the vehicle heating target component 1. For example, the substrate 10 of the decorative component 1a has a decorative design printed or attached on its surface, or a decorative layer disposed on the back of a design portion formed of a transparent material. The substrate 10 of the decorative component 1b has a surface shape that decorates the vehicle 2. The substrate 10 of the bumper 1c is formed in a plate shape to absorb impacts on the lower part of the vehicle 2. The substrate 10 of the decorative component 1a and the substrate 10 of the decorative component 1b are installed, for example, by claw fitting into openings (i.e. holes or grooves) provided in the front bumper or rear bumper of the vehicle 2. Hereinafter, the substrate 10 is assumed to be installed in the opening of the front bumper of the vehicle 2.

The resin material of the substrate 10 is a material with excellent millimeter wave transparency, which allows the millimeter waves transmitted by the millimeter wave radar device 3 to pass through. The substrate 10 is preferably formed opaque so that the millimeter wave radar device 3, which is located behind the substrate 10 on the vehicle, cannot be seen through the substrate 10. The substrate 10 is formed from a resin material such as ASA (acrylonitrile-styrene-acrylate copolymer) resin, AES (acrylonitrile-ethylene-styrene copolymer) resin, polycarbonate resin, polypropylene resin (PP), or acrylonitrile-butadiene-styrene copolymer resin (ABS). The substrate 10 is molded, for example, by injection molding.

The substrate 10 has a plate wall portion 11 and a support portion 12. The plate wall portion 11 is a portion formed in a plate shape. The plate wall portion 11 is formed to match the size of an opening provided in the front bumper or the like of the vehicle 2. The plate wall portion 11 is arranged so that it fits into the opening and faces in the longitudinal direction of the vehicle and has its front surface exposed to the outside of the vehicle. After the molding of the vehicle heating target part 1 is completed, the plate wall portion 11 is configured so that the front surface (i.e., the surface facing outward) 11a and the rear surface (i.e., the back surface facing inward) 11b are each curved without any unevenness. The curvature of the plate wall portion 11 (particularly its surface) is formed so that the plate wall portion 11 (particularly its surface) forms the same surface in accordance with the front bumper (particularly its surface) of the vehicle 2. The degree of curvature of the plate wall portion 11 (particularly its surface 11a) is, for example, R400 or more.

The plate wall portion 11 is disposed in the radio wave transmission direction (front of the vehicle) relative to the millimeter wave radar device 3. The plate wall portion 11 is a portion through which the millimeter waves used in the millimeter wave radar device 3 pass. The plate wall portion 11 has a thickness within a range of 2 mm to 4 mm (for example, a thickness of 2.4 mm or 3.6 mm). Note that this thickness of the plate wall portion 11 is the maximum thickness of the plate wall portion 11, and may be the thickness of a portion where the recess 13 described below does not exist.

The support portion 12 is a portion for attaching the substrate 10 and thus the vehicle heating target part 1 to the front bumper of the vehicle 2. The support portion 12 is integrally molded with the plate wall portion 11 and is connected to both ends (e.g., the upper and lower ends) of the plate wall portion 11. The pair of support portions 12 are provided so as to protrude rearward from both ends of the plate wall portion 11. The support portions 12 may have a plate-like shape extending in the left-right direction of the vehicle, or may be scattered at predetermined intervals in the left-right direction of the vehicle.

The pair of support parts 12 described above extend parallel to each other toward the rear, and each has elasticity in the direction of moving toward and away from each other. The pair of support parts 12 each have a claw part (not shown) that protrudes in a direction away from each other. The heated vehicle part 1 is attached to the front bumper of the vehicle 2 by hooking the claw part of the support part 12 onto the front bumper with the plate wall part 11 fitted into the opening described above.

The substrate 10 also has a recess 13. The recess 13 is a portion formed in a concave shape on the back surface 11b of the plate wall portion 11. The recess 13 is formed in a portion of the entire back surface 11b of the plate wall portion 11. This portion is, for example, a central portion excluding the vicinity of the connection portion with the support portion 12 on the back surface 11b or excluding the periphery of the back surface 11b of the plate wall portion 11. The back surface 11b of the plate wall portion 11 is formed to have two steps due to the presence of the recess 13. The plate wall portion 11 is formed so that the plate thickness is relatively large near the connection portion with the support portion 12 and relatively small at the recess 13.

The size of the recess 13 corresponds to the area where ice and snow adhering to the surface 11a of the plate wall portion 11 is melted using the heating sheet 20, and corresponds to the area through which millimeter waves must pass in order to detect objects outside the vehicle using the millimeter wave radar device 3. The recess 13 has a depth that is approximately constant relative to the curved substrate 10, and the depth of the recess 13 is approximately equal to the thickness of the heating sheet 20.

The heating sheet 20 is a member that heats the substrate 10 (particularly, the surface of the plate wall portion 11). The heating sheet 20 is formed in a thin sheet shape. The heating sheet 20 has flexibility and pliability. The heating sheet 20 is formed, for example, by extrusion molding or press molding. The heating sheet 20 is disposed on the back surface 11b of the plate wall portion 11 of the substrate 10. Specifically, the heating sheet 20 is disposed in a recess 13 formed in a part of the entire area of the back surface 11b . The substrate 10 and the heating sheet 20 are welded to each other. The substrate 10 and the heating sheet 20 are insert molded.

The heating sheet 20 has a sheet portion 21 and a heater wire 22. The sheet portion 21 is a portion formed in a sheet shape. The sheet portion 21 has the function of holding the heater wire 22 and protecting the metallic heater wire 22 from corrosion. The sheet portion 21 is formed to fit into the recess 13 and has a size corresponding to the size (area) of the recess 13. The sheet portion 21 has a thickness of 1.2 mm or less, for example, a thickness in the range of 0.4 mm to 1.2 mm (preferably, a thickness in the range of 0.5 mm to 0.8 mm).

The material of the sheet portion 21 is soft and flexible, has excellent adhesion to the substrate 10 when the heating sheet 20 and the substrate 10 are integrated by welding, and has excellent transparency to the millimeter waves transmitted by the millimeter wave radar device 3. The sheet portion 21 is made of a material such as polypropylene resin (PP), acrylonitrile butadiene styrene copolymer resin (ABS), polycarbonate (PC), polyethylene terephthalate (PET), etc. It is preferable that the material of the sheet portion 21 is a thermoplastic resin of the same material (including grade) as the substrate 10, but may be a material different from the substrate 10. The sheet portion 21 is molded, for example, by extrusion molding.

The heater wire 22 is a part that generates heat when electricity is passed through it. The heater wire 22 is made of a material such as copper. The heater wire 22 is formed to extend linearly and has a circular cross section. The heater wire 22 is electrically connected to a power source (not shown) via a control unit (not shown). The heater wire 22 generates heat when power is supplied based on a command from the control unit.

After the heating sheet 20 is formed, the heater wire 22 is embedded in the sheet portion 21. Specifically, after the heating sheet 20 is formed, the heater wire 22 is embedded in the opposing surface 21a of the sheet portion 21 that faces the bottom surface 13a of the recess 13. Only a portion of the heater wire 22 is embedded in the sheet portion 21 on the cross section. The remaining portion of the heater wire 22 is exposed upward from the surface of the sheet portion 21 on the cross section. The heater wire 22 embedded in the sheet portion 21 is arranged in a region or space in the sheet portion 21 that does not interfere with the transmission and reception of millimeter waves by the millimeter wave radar device 3. The heater wire 22 is embedded in the sheet portion 21 by ultrasonic welding, heat welding, vibration welding, or the like using a press molding machine (see FIG. 3).

Next, an example of a manufacturing method for the heated vehicle part 1 will be described with reference to Figures 3 and 4. Note that the manufacturing method for the heated vehicle part 1 is not limited to this, and other methods may be used.

First, the heating sheet 20 of the vehicle heating target part 1 is formed as follows. Specifically, the sheet portion 21 constituting the heating sheet 20 is formed by extrusion molding so as to have a thickness of 1.2 mm or less (FIG. 3(A)). After that, the sheet portion 21 is heated, and then the heater wire 22 is embedded in the sheet portion 21 by the press molding machine 50, thereby forming the heating sheet 20 by welding (FIG. 3(B)). Then, the formed heating sheet 20 is removed from the press molding machine 50 (FIG. 3(C)).

The heated vehicle part 1 is molded using a male mold 61 and a female mold 62 of an injection molding machine 60. The male mold 61 is formed to have a convex surface corresponding to the back surface shape of the heated vehicle part 1 after molding. The female mold 62 is formed to have a concave surface corresponding to the surface shape of the heated vehicle part 1 after molding. The male mold 61 and the female mold 62 are arranged so that they are clamped together in a state in which a cavity 63 (see FIG. 4(C)) that matches the desired outer shape of the heated vehicle part 1 is formed. At least one of the male mold 61 and the female mold 62 is movable in a direction that moves them apart relative to one another.

After the heating sheet 20 is molded as described above, the heating sheet 20 is placed on the convex surface of the male mold 61, which is separated from the female mold 62 (FIG. 4(A)). The heating sheet 20 is then shaped onto the convex surface of the male mold 61 (FIG. 4(B)), and the male mold 61 and the female mold 62 are clamped together (FIG. 4(C)). The resin material constituting the base material 10 is then poured into the cavity 63 to fill it, and then cooled, thereby performing insert molding of the vehicle heating target part 1 in which the base material 10 and the heating sheet 20 are integrated by welding (FIG. 4(D)). After performing such insert molding, the male mold 61 and the female mold 62 are removed, and the molded vehicle heating target part 1 is taken out.

In this way, in the vehicle heated part 1, the substrate 10 and the heating sheet 20 are formed with the heating sheet 20 placed on the back surface 11b of the plate wall portion 11 of the substrate 10. The plate wall portion 11 of the substrate 10 and the sheet portion 21 of the heating sheet 20 are each portions with excellent millimeter wave transparency. The vehicle heated part 1 is placed ahead of the millimeter wave radar device 3 in the radio wave transmission direction. Therefore, the vehicle heated part 1 can hide the millimeter wave radar device 3 so that it cannot be seen from the front side of the vehicle, and can transmit millimeter waves transmitted and received by the millimeter wave radar device 3.

The substrate 10 is arranged so that the surface 11a of the plate wall portion 11 is exposed to the outside of the vehicle through an opening in the front bumper of the vehicle 2. A heating sheet 20 is then arranged on the back surface 11b of the plate wall portion 11. The heating sheet 20 has a sheet portion 21 and a heater wire 22 embedded in an opposing surface 21a of the sheet portion 21 that faces the back surface 11b of the plate wall portion 11 (specifically, the bottom surface 13a of the recess 13). The heater wire 22 generates heat when electricity is applied.

When the heater wire 22 generates heat, the substrate 10 is heated by heat transfer. Therefore, even if ice and snow adhere to the surface 11a of the substrate 10 exposed to the outside of the vehicle in the heated vehicle component 1, the ice and snow on the surface 11a of the substrate 10 can be melted by heat transfer from the heater wire 22 to the substrate 10. Therefore, by arranging the heating sheet 20 on the back surface of the substrate 10, the millimeter wave transmittance of the heated vehicle component 1 can be ensured.

The base material 10 and the heating sheet 20 are integrated by welding using insert molding. In this structure, the base material 10 and the heating sheet 20 can be integrated without using adhesive. This allows the heating target component 1 for a vehicle to be constructed at low cost, and prevents the millimeter wave transmittance from being impaired due to the presence of adhesive between the base material 10 and the heating sheet 20, thereby improving the millimeter wave transmittance.

In addition, the heating member for heating the substrate 10 is a heating sheet 20 that is thin and flexible. As a result, in the structure in which the substrate 10 and the heating sheet 20 are integrated by welding using insert molding as described above, the heating sheet 20 can be shaped to conform to the vehicle heating target part 1 having various shapes (e.g., curved surfaces) that imitate the injection molding machine 60. This ensures high versatility of the heating sheet 20 without preforming the heating sheet 20, and reduces costs in molding the vehicle heating target part 1.

The heating sheet 20 is also placed in a recess 13 on the back surface 11b of the substrate 10. The recess 13 is formed in a portion of the entire back surface 11b of the plate wall portion 11. In this structure, a portion of the substrate 10 is thinned, thereby shortening the distance between the front surface 11a of the substrate 10 and the heating sheet 20 placed on the back surface 11b of the substrate 10, thereby improving the heat transfer from the heating sheet 20 to the substrate 10.

On the other hand, the portions of the base material 10 other than the portion where the recess 13 is provided (specifically, the vicinity of the connection portion of the plate wall portion 11 with the support portion 12) are maintained thick. Therefore, compared to a structure in which the entire base material 10 is formed thin, the rigidity of the base material 10 (particularly, the vicinity of the connection portion of the plate wall portion 11 with the support portion 12) can be increased. In particular, the support portion 12 is a portion where the base material 10 is attached to the front bumper of the vehicle 2, and is an elastic portion. Therefore, by maintaining the vicinity of the connection portion of the plate wall portion 11 with the support portion 12 thick, the mounting stability of the heated vehicle component 1 to the front bumper of the vehicle 2 can be ensured.

Therefore, according to the vehicle heated part 1, the heating sheet 20 is placed in the recess 13 formed in a part of the entire area of the back surface 11b of the plate wall portion 11 of the base material 10, thereby ensuring heat transfer from the heating sheet 20 to the base material 10 without impairing the rigidity of the base material 10.

In the above embodiment, the depth of the recess 13 and the thickness of the heating sheet 20 are approximately the same, and the heating sheet 20 is arranged so that the entire heating sheet 20 fits within the recess 13. However, the present invention is not limited to this, and may be applied to an embodiment in which the thickness of the heating sheet 20 is greater than the depth of the recess 13, as shown in FIG. 5, and the heating sheet 20 is arranged so that a portion of the heating sheet 20 fits within the recess 13 and the remaining portion protrudes from the recess 13 in the thickness direction of the heating sheet 20.

In the configuration of this modified form, the depth of the recesses 13 in the substrate 10 can be reduced while maintaining the thickness of the heating sheet 20, compared to the configuration of the above embodiment. If the recesses 13 are present, a thickness difference will occur in the substrate 10, and the difference in resin shrinkage associated with this thickness difference may cause lines to appear on the substrate surface, affecting the design. If the depth of the recesses 13 is reduced, the appearance of these lines on the substrate surface is less likely to occur. Therefore, with this modified form, the design of the surface side of the substrate 10 can be ensured.

Conversely, the thickness of the heating sheet 20 may be smaller than the depth of the recess 13, and the entire heating sheet 20 may be completely contained within the recess 13.

In the above embodiment, the recess 13 has a substantially constant depth relative to the substrate 10. However, the present invention is not limited to this, and may be applied to a form in which the depth of the recess 13 gradually changes (for example, the depth of the recess 13 gradually decreases from the end to the center, or conversely, the depth of the recess 13 gradually decreases from the center to the end). According to this modified form, the recess 13 of the desired shape can be formed in the substrate 11 without compromising the design on the surface side of the substrate 11. Furthermore, in the structure of this modified form, the degree to which the heating sheet 20 fits in the recess 13 and the amount by which it protrudes from the recess 13 change depending on the region position.

The present invention is not limited to the above-described embodiments, modifications, and application examples, and various modifications can be made without departing from the spirit of the present invention.

1: Vehicle part to be heated, 2: Vehicle, 3: Millimeter wave radar device, 10: Base material, 11: Plate wall portion, 13: Recess, 20: Heating sheet, 21: Sheet portion, 22: Heater wire, 50: Press molding machine, 60: Injection molding machine, 61: Male mold, 62: Female mold, 63: Cavity.

Claims (4)

A plate-shaped base material capable of transmitting millimeter wave electric waves;
A sheet-like heating sheet is disposed on the back surface of the substrate to heat the substrate;
A vehicle heating target part comprising:
The base material has a plate wall portion formed in a plate shape and a recess portion formed in a concave shape in a part of the entire back surface of the plate wall portion,
the heating sheet is disposed in the recess, and includes a sheet portion formed in a sheet shape having a size corresponding to the recess, and a heater wire having a cross section partially embedded in an opposing surface of the sheet portion opposing a bottom surface of the recess and a remaining portion exposed from the opposing surface of the sheet portion and in contact with the base material in a semi-cylindrical shape ;
The heating target part for a vehicle, wherein the base material and the heating sheet are integrated by welding. A method for manufacturing a vehicle heating target part, comprising: a plate-shaped base material capable of transmitting millimeter wave radio waves; and a sheet-shaped heating sheet disposed on a rear surface of the base material to heat the base material,
The base material has a plate wall portion formed in a plate shape and a recess portion formed in a concave shape in a part of the entire back surface of the plate wall portion,
the heating sheet is disposed in the recess, and includes a sheet portion formed in a sheet shape having a size corresponding to the recess, and a heater wire having a cross section partially embedded in an opposing surface of the sheet portion opposing a bottom surface of the recess and a remaining portion exposed from the opposing surface of the sheet portion and in contact with the base material in a semi-cylindrical shape ;
A manufacturing method for a heated vehicle part, comprising the steps of: placing the heating sheet inside a mold, closing the mold, and pouring the material of the base material into the cavity of the mold to integrate the base material and the heating sheet by welding. The heated vehicle part according to claim 1, wherein the heating sheet has a thickness within a range of 0.4 mm to 1.2 mm. 4. The vehicle part to be heated according to claim 1, wherein the vehicle part is disposed ahead of a millimeter wave radar device that transmits the radio waves in a radio wave transmission direction.

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