Patent Description:
Various types of equipment such as audio equipment and an air-conditioning operation unit are disposed in an instrument panel of an automobile or the like. These types of in-vehicle equipment are usually removably fixed so that the equipment is able to be maintained or replaced, and mating portions around mounting portions of the equipment are each covered with a garnish separate from an instrument panel body in order to maintain a favorable interior appearance. Accordingly, the garnish is also removably provided on the instrument panel body, and the garnish is configured to be removed before removal of the in-vehicle equipment so that the mounting portion of the in-vehicle equipment is exposed.

For example, Patent Literature <NUM> describes an instrument panel in which a garnish according to the preamble of claim <NUM> is attached with a peripheral edge thereof overlapped on a panel body and an edge portion of an attachment member such as another garnish, the instrument panel being characterized in that a rib stands upright on the edge portion of the attachment member and the garnish is attached by hooking the peripheral edge of the garnish on the rib.

A garnish is required to exhibit impact resistance, which makes it necessary to use a resin material that is excellent in impact resistance to mold the garnish. There are various resin materials excellent in impact resistance and a polymer alloy of polycarbonate and acrylonitrile-butadiene-styrene (hereinafter, also referred to as "PC/ABS resin") is thought to have a high impact resistance. However, the present inventors have found that the expected impact resistance fails to be exhibited when a garnish is molded from a PC/ABS resin.

Accordingly, in view of the above-described problem, an object of the present invention is to provide a garnish for an instrument panel, the garnish exhibiting excellent impact resistance even though it is molded from a PC/ABS resin.

To achieve the above-described object, the present invention provides a garnish in a form of a frame configured to cover a periphery of in-vehicle equipment disposed around a middle of an instrument panel, the garnish including an opening portion around a middle defined by an upper frame, a lower frame, and right and left frames of the garnish, in which respective outer peripheral portions and inner peripheral portions of the upper frame, the lower frame, and the right and left frames project toward the in-vehicle equipment, the garnish is formed of a polymer alloy of polycarbonate and acrylonitrile-butadiene-styrene (a PC/ABS resin), and a gate mark is provided on at least one of the upper frame, the lower frame, and the right and left frames between the outer peripheral portion and the inner peripheral portion, projecting toward the in-vehicle equipment.

Thus, according to the present invention, a garnish for an instrument panel can exhibit excellent impact resistance even though it is molded from a PC/ABS resin.

One embodiment of a garnish for an instrument panel according to the present invention is described below with reference to the attached drawings.

<FIG> is an example of an instrument panel for a right-hand-drive vehicle, which is provided in a front portion of a vehicle interior. As illustrated in <FIG>, in an instrument panel body <NUM>, a dashboard (not illustrated) including a speedometer, a fuel gauge, and the like is disposed on a right side as viewed by an observer, a decorative panel, that is, cluster panel <NUM>, covering a periphery of the dashboard is provided, and an upper storage box <NUM> is provided on a left side as viewed by an observer. Around a middle as viewed by an observer, a car navigation system <NUM> is installed and a decorative panel, that is, garnish <NUM>, covering a periphery of the car navigation system <NUM>, is disposed. A decorative panel, that is, heater control panel <NUM>, for an air-conditioning unit such as an air conditioner or a heater is disposed below the garnish <NUM>. In addition, a center louver mechanism <NUM> is provided on both sides of the garnish <NUM>, serving as a vent of the air-conditioning unit around a middle in the vehicle interior.

The cluster panel <NUM>, the storage box <NUM>, the garnish <NUM>, and the heater control panel <NUM> are each molded from a resin, located at a position projecting toward the vehicle interior with respect to the center louver mechanism <NUM>, and provided with a cavity in an internal cross-section to exhibit a buffering action to absorb an impact.

As illustrated in <FIG>, the garnish <NUM>, which is a thinned frame surrounding a display of the car navigation system <NUM>, is configured to cause the instrument panel body <NUM> to project toward the vehicle interior. As illustrated in <FIG>, the garnish <NUM> mainly includes, as viewed from a vehicle-interior side, an upper frame <NUM>, a lower frame <NUM>, a right frame <NUM>, and a left frame <NUM>, which define an opening around a middle. A longitudinal direction of the garnish <NUM> is along a vehicle-width direction. In other words, the upper frame <NUM> and the lower frame <NUM> are longer than the left and right frames <NUM>, <NUM>.

For attachment of the garnish <NUM> to the instrument panel body, a positioning pin <NUM> projecting from the garnish <NUM> is inserted into a positioning hole <NUM> of a bracket <NUM> of the instrument panel body, and the garnish <NUM> is fastened by inserting a screw into an attachment hole (not illustrated) of the garnish <NUM>. In addition, a clip <NUM> of the garnish <NUM> is inserted into an engagement hole (not illustrated) of the instrument panel body for fixation.

As illustrated in <FIG>, each of the upper frame <NUM>, the lower frame <NUM>, the right frame <NUM>, and the left frame <NUM> of the garnish <NUM> has an outer peripheral portion and an inner peripheral portion (i.e., a peripheral portion on an opening side) projecting toward the in-vehicle equipment (i.e., an opposite side to the vehicle interior). The garnish <NUM> of the present embodiment is formed of a PC/ABS resin, and gate marks <NUM>, <NUM>, which are attributed to injection molding, are provided on the upper frame <NUM> and the lower frame <NUM>, respectively, projecting toward the in-vehicle equipment.

As illustrated in <FIG>, the gate mark <NUM> of the upper frame <NUM> is located not on an outer peripheral portion 11a or an inner peripheral portion 11b of the upper frame <NUM> projecting toward the in-vehicle equipment, but between these portions. Molding the garnish <NUM> using a submarine gate causes the gate mark <NUM> to be made at such a position. A distance of the gate mark <NUM> from the outer peripheral portion 11a and the inner peripheral portion 11b is preferably equal to or greater than <NUM>, more preferably equal to or greater than <NUM>. Thus, injection molding is performed using a PC/ABS resin from a gate opening at the position distant from the outer peripheral portion 11a and the inner peripheral portion 11b, which makes it possible to notably improve the impact resistance of the garnish <NUM>.

It is preferable that the gate mark <NUM> be offset to the inner peripheral portion 11b with respect to a center between the outer peripheral portion 11a and the inner peripheral portion 11b of the upper frame <NUM>. The gate mark <NUM> may be a cause of a reduction in impact resistance. However, offsetting the gate mark to the inner peripheral portion 11b on the lower side makes the garnish <NUM> unlikely to fracture, since if a person in the vehicle hits the garnish <NUM> due to an accident or the like, it is supposed that the person is likely to hit an upper side of the upper frame <NUM>.

The gate mark <NUM> of the upper frame <NUM> has substantially a plate shape with a width direction thereof being along the longitudinal direction of the garnish <NUM> and the shape is gradually flared toward the upper frame <NUM>. Injection molding is performed using a gate opening providing the gate mark <NUM> in such a shape, which makes it possible to prevent the occurrence of a crack in the garnish <NUM>.

Likewise, as illustrated in <FIG>, the gate mark <NUM> of the lower frame <NUM> is located not on an outer peripheral portion 12a or an inner peripheral portion 12b of the lower frame <NUM> projecting toward the in-vehicle equipment, but between these portions by virtue of molding using the submarine gate. A distance of the gate mark <NUM> from the outer peripheral portion 12a and the inner peripheral portion 12b is preferably equal to or greater than <NUM>, more preferably equal to or greater than <NUM>. Thus, injection molding is performed using a PC/ABS resin from a gate opening at a position distant from the outer peripheral portion 12a and the inner peripheral portion 12b, which makes it possible to notably improve the impact resistance of the garnish <NUM>.

It is preferable that the gate mark <NUM> be offset to the outer peripheral portion 12a with respect to a center between the outer peripheral portion 12a and the inner peripheral portion 12b of the lower frame <NUM>. As described above, the gate mark <NUM> may be a cause of a reduction in impact resistance. However, providing the gate mark on the outer peripheral portion 12a on the lower side makes the garnish <NUM> unlikely to fracture, since if a person in the vehicle hits the garnish <NUM> due to an accident or the like, it is supposed that the person is likely to hit an upper side of the lower frame <NUM>.

Likewise, the gate mark <NUM> of the lower frame <NUM> also has substantially a plate shape with a width direction thereof being along the longitudinal direction of the garnish <NUM> and the shape is gradually flared toward the lower frame <NUM>.

Thus, the two gate marks <NUM>, <NUM> exist in the garnish <NUM>. This is because the single garnish <NUM> is molded from the two gate openings by injection molding. Such injection molding using the two gate openings located at the gate marks <NUM>, <NUM> causes weld lines 20a, 20b where molten resins meet to be formed at corners of the garnish <NUM> as illustrated in <FIG>. Such formation of the weld lines 20a, 20b at the corners of the garnish <NUM> increases an angle at which the resins meet, thereby making it possible to improve an appearance of a portion corresponding to the weld lines 20a, 20b.

As illustrated in <FIG>, a height of the gate mark <NUM> of the upper frame <NUM> is higher than a height B of the inner peripheral portion 11b of the upper frame. By virtue of the height being higher than that of the inner peripheral portion 11b as described above, it is possible to automatically perform gate cutting at a timing when demolding of the injection molding is performed or, in a case in which nippers or the like are used to perform gate cutting, it is possible to secure a workspace for them. In addition, the height of the gate mark <NUM> of the upper frame <NUM> is lower than a height A of the outer peripheral portion 11a of the upper frame. By virtue of the height being lower than that of the outer peripheral portion 11a as described above, it is possible to secure a designed space on an in-vehicle-equipment side.

The formation of the gate mark <NUM> is described with reference to <FIG>. The garnish <NUM> is injection-molded using a submarine gate <NUM>. This makes it possible to place the gate opening of a mold (not illustrated) not in the projecting outer peripheral portion 11a and inner peripheral portion 11b of the upper frame <NUM>, but at a portion therebetween. Thus, the gate mark 17a, which is higher than the outer peripheral portion 11a of the upper frame as illustrated in <FIG> immediately after demolding, is able to be cut at a position C lower than the outer peripheral portion 11a of the upper frame with nippers or the like. Note that the gate mark may be automatically cut during demolding as described above. Note that the gate mark <NUM> of the lower frame <NUM> may be likewise formed and cut.

As illustrated in <FIG>, a height of the gate mark <NUM> of the lower frame <NUM> is higher than the height B of the inner peripheral portion 12b of the lower frame. By virtue of the height being higher than that of the inner peripheral portion 12b as described above, it is possible to automatically perform gate cutting at a timing when demolding of the injection molding is performed or, in a case in which nippers or the like are used to perform gate cutting, it is possible to secure a workspace for them. In addition, the height of the gate mark <NUM> of the lower frame <NUM> is lower than a height A of the outer peripheral portion 12a of the lower frame. By virtue of the height being lower than that of the outer peripheral portion 12a as described above, it is possible to secure a designed space on the in-vehicle-equipment side.

A plate molded article (<NUM> x <NUM> x thickness <NUM>, a fine gate plate) of a PC/ABS resin (manufactured by Mitsubishi Engineering-Plastics Corporation, MB2215R) was produced by injection molding and strip specimens (<NUM> x <NUM> x thickness <NUM>) in a resin flowing direction (an MD direction) and a vertical direction (a TD direction) were cut out of the plate molded article using an automatic sample molding machine. <FIG> illustrates a spot at which the specimen in the TD direction was collected and <FIG> illustrates a spot at which the specimen in the MD direction was collected.

As illustrated in <FIG>, a plate molded article <NUM> is an article molded from a resin flowing in an arrow direction from a gate opening <NUM> of an injection molding machine. A strip specimen <NUM> in the TD direction is a specimen cut such that a longitudinal direction of the strip specimen was vertical to the flow direction. A distance a from an end surface of the plate molded article <NUM> on a side toward the gate opening <NUM> to a centerline of a first specimen (TD1) in the TD direction was <NUM>. In contrast, a strip specimen <NUM> in the MD direction is a specimen cut out of the plate molded article <NUM> such that a longitudinal direction of the strip specimen <NUM> was the same as the flowing direction indicated by an arrow as illustrated in <FIG>. A distance b from a centerline of the plate molded article <NUM> to a centerline of a first specimen (MD1) in the MD direction was <NUM>.

The specimens in the TD direction and the MD direction were each notched (R = <NUM>) such that a remaining width was <NUM>. Then, a Charpy impact test was performed, and a Charpy impact value of each specimen was measured. Note that the Charpy impact test was performed using a Charpy impact tester (manufactured by Toyo Seiki Seisaku-sho, Ltd. , model: IMPACT TESTER IT) in conformity with JIS K <NUM>. The test temperature was <NUM> and the hammer was 4J.

As a result, all the specimens <NUM> in the MD direction suffered partial fracture (P fracture) as illustrated in <FIG>. Note that an arrow in the figure is a direction of hitting with a hammer during the Charpy impact test, which is an opposite direction to the resin flowing direction. In addition, Charpy impact values of the specimens (MD1 to MD10) in the MD direction were stably high values. No dependency on the specimen collection spot was observed. In contrast, it was observed that the specimens in the TD direction had a dependency on the specimen collection spot. The specimens (TD12 to TD14) in a portion in the vicinity of a flow end distant from the gate opening of injection molding suffered P fracture or hinge fracture (H fracture), whereas the specimen <NUM> (TD1 to TD11) in the TD direction close to a portion near the gate opening suffered complete fracture (C fracture) as illustrated in <FIG>. Similarly, for the Charpy impact value, while being low near the gate opening and around a middle portion, the impact value increased with a reduction in distance to the flow end. With an assumption of an average of the Charpy impact values of the specimens in the MD direction being <NUM>, even the highest value (TD14) among those of the specimens was merely <NUM>, and an average thereof was <NUM>, which was considerably low.

As described above, a specimen fracture morphology was different between the MD direction and the TD direction and the Charpy impact values of the specimens in the TD direction were equal to or less than a half of those of the specimens in the MD direction. Accordingly, molding a component with a high impact resistance from a PC/ABS resin requires measures for maintaining a high impact resistance value even in the TD direction.

A Charpy impact value of each specimen in the MD direction and the TD direction was measured as in Test Example <NUM>, except that a PC resin (manufactured by Mitsubishi Engineering-Plastics Corporation, S-3000R) was used in place of the PC/ABS resin.

As a result, it was not observed that the PC resin had anisotropy depending on the resin flowing direction, as the PC/ABS resin in Test Example <NUM>. As for the Charpy impact value of the PC resin, assuming that an average of the Charpy impact values of the specimens in the MD direction in Test Example <NUM> was <NUM>, an average of the specimens in the MD direction was <NUM> and an average of the specimens in the TD direction was <NUM>. All the specimens of the PC resin suffered P fracture. From this result, the anisotropy of the PC/ABS resin is thought to originate from an ABS resin and is speculated to be attributed to, in particular, an orientation of rubber in the ABS resin.

With use of a submarine gate, a strip specimen in the TD direction with a gate opening placed in the specimen was produced and a Charpy impact test was performed. First, a plate molded article was molded using a submarine gate <NUM> (gate opening: <NUM> x <NUM>) such that a gate opening <NUM> of the submarine gate <NUM> was placed inside with respect to an end surface of the plate molded article <NUM> as illustrated in <FIG>. Note that CK43-D4 manufactured by Techno-UMG Co. , was used as the PC/ABS resin. JSW180ton manufactured by The Japan Steel Works, Ltd. , was used as the molding machine and a one-gate plate-shaped mold was used as the mold. A distance L between the gate opening <NUM> and the end surface of the plate molded article <NUM> (hereinafter, referred to as "gate distance") was changed by changing a shape of a PL surface (a mating surface of the mold) of a portion that is a loose piece (not illustrated). The specimen <NUM> was in the form of a strip specimen in the TD direction (<NUM> x <NUM> x thickness <NUM>) as illustrated in <FIG> and was cut out along the end surface of the plate molded article <NUM>.

Five of each of three types of specimens with gate distances L of <NUM>, <NUM>, and <NUM> were produced, and a Charpy impact test was performed using the Charpy impact tester in conformity with JIS K <NUM> as in Test Examples <NUM> and <NUM>. Note that no notch was made, and the hammer was <NUM> J in Test Example <NUM>.

In addition, for comparison, five strip specimens in the TD direction with gate openings <NUM> placed on end portions of specimens <NUM> were produced using a side gate <NUM> as illustrated in <FIG> and a Charpy impact test was performed under conditions similar to those described above. Table <NUM> shows a result for each specimen. Note that the Charpy impact values in Table <NUM>, which are averages of measurement results of the five specimens of each type, are not measurement values (unit: KJ/m<NUM>), but are relative values, with an assumption that the average of the Charpy impact values of the specimens in the MD direction in Test Example <NUM> is <NUM>. In addition, as for the specimens with the gate distances L of <NUM> and <NUM> molded using the submarine gate, <FIG> illustrates observation results of fracture morphologies caused by the Charpy impact test.

As illustrated in <FIG>, specimens <NUM> with the gate distance L of <NUM> and specimens <NUM> with the gate distance L of <NUM>, which were molded using the submarine gate, all suffered complete fracture (C fracture). However, as for the specimens <NUM> with the gate distance L of <NUM>, almost no plastically deformed region was observed in a crack occurrence portion, and additionally, the impact resistance was low. In contrast, as for the specimens <NUM> with the gate distance L of <NUM>, a plastic deformation <NUM> was observed in a crack occurrence portion, and additionally, the impact resistance was more than twice as high as that of the specimens with the gate distance L of <NUM> as shown in Table <NUM>.

Although not illustrated in <FIG>, a plastic deformation was observed also in crack occurrence portions of the specimens with the gate distance L of <NUM> and the impact resistance was notably high as shown in Table <NUM>. In contrast, as for the specimens molded using the side gate (of course, the gate distance L was <NUM>), although not illustrated in <FIG>, almost no plastically deformed region was observed in the crack occurrence portions, and additionally, the impact resistance was low as shown in Table <NUM>.

Claim 1:
A garnish (<NUM>) for an instrument panel (<NUM>), the garnish (<NUM>) being in a form of a frame configured to cover a periphery of in-vehicle equipment disposed around a middle of an instrument panel, the garnish (<NUM>) comprising:
an opening portion around a middle defined by an upper frame (<NUM>), a lower frame (<NUM>), and right and left frames (<NUM>, <NUM>) of the garnish (<NUM>),
respective outer peripheral portions and inner peripheral portions of the upper frame (<NUM>), the lower frame (<NUM>), and the right and left frames (<NUM>, <NUM>) projected toward the in-vehicle equipment (Fr), characterized in that
the garnish (<NUM>) is formed of a polymer alloy of polycarbonate and acrylonitrile-butadiene-styrene (a PC/ABS resin), and
a gate mark (<NUM>, <NUM>) is provided on at least one of the upper frame (<NUM>), the lower frame (<NUM>), and the right and left frames (<NUM>, <NUM>) between the outer peripheral portion and the inner peripheral portion, projecting toward the in-vehicle equipment (Fr).