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New products

Introduction of Infiniti Q30/QX30 Cockpit Module

Yuuya Miyazaki*

AbstractInfiniti Q30/QX30 is the first premium compact segment model for Infiniti brand. This model is using Nissan’s partnership with Daimler to share the components of Daimler’s compact car architecture. It is the first European production car of the Infiniti brand produced at Nissan Motor Manufacturing UK Ltd.. Q30/QX30 has been developed to feature high-quality and luxurious design in its interior and exterior. This paper describes the CPM with such high-end specification beyond the entry-level premium segment.

Key Words : Interior, Instrument panel / Cockpit module

1. Introduction One of our objectives in the CockPit Module (CPM) de-velopment for Infiniti Q30/QX30 (hereafter referred to as Q30) was to produce a luxurious interior that falls in the premium segment. In particular, to offer a rigid feel on the Instrument Panel (IP), the internal structure was enhanced from conventional products, and the glass-fi-ber reinforced polypropylene material was applied as our previous products in front end modules. To provide luxurious quality on the parts where customers acknowl-edge by viewing and touching, a vacuum bonding tech-nology was adopted for adhesion of skin and the upper IP surface, and soft pads were equipped with wrapped genuine leather that are three-dimensionally sewn with high quality stitches. The following sections introduce our efforts on the CPM development.

2. Interior Specification2.1. AbundanceofSkinWrapping

Fig. 1 shows the interior space of the Q30. In the pre-mium specifications, the skin is placed over the upper IP surface in the vacuum bonding process, whereas the upper pad at the driver side and the passenger facing middle pad are manually wrapped with the stitched skin pads which are adopted in many premium segments for presentation of craftsmanship.

Fig. 1 Infiniti Q30 interior(https://www.infiniti.com)

Remarkably, the pad specification at the passenger facing middle pad is selectable from genuine, Alcan-tara, and synthetic leather materials, each of which has several color variations for the leather and stitches. The pad variations fulfill recent demands for personalization in the premium segments and provide higher qualities than general entry class models. In addition, we established production and quality assurance processes that secured high quality appear-ances of the sewn parts, such as pitch and parallelism of the finished stitches.

* CPM &Interior Business Unit, CPM & Interior Engineering Development Group

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CALSONIC KANSEI TECHNICAL REVIEW vol.13 2017

Fig. 2 Infiniti Q30 interior passenger pad(https://www.infiniti.com)

2.2. HighQualityDecoration As a decorative accent, satin chrome plating is applied on the outer frame of the air conditioning grille to give fine and sophisticated impression. To render a premium sensation, the airflow adjuster dial is formed by double injection, and it provides a soft touch feel and a visual effect on airflow indication. Piano black finishing is ap-plied around the audio switches as a standard specifica-tion while the real wood specification is provided as an option. These specifications in the Q30 are superior to those in general entry classes.

Fig. 3 Infiniti Q30 center-area interior piano black paint decoration(https://www.infiniti.com)

Fig. 4 Infiniti QX30 center-area interior real wood decoration(https://www.infiniti.com)

3. High Rigidity IP Structure3.1. IPStructure

In the Q30 development, we put another effort on mak-ing the entire IP rigid to provide a premium feel. As shown in Fig. 5, the upper pad gets rigidity with open channels of air conditioning ducts that are closed by welding to the IP substrate. This is what we call a ducted structure. Conventionally, the upper pad must be rigid by itself. In the ducted structure, the upper pad has high rigidity with the duct sections.

Fig. 5 Image of “ducted” structure

Our conventional IP products already have a ducted structure where only front edges of the IP are welded as shown in Fig. 6. In the Q30 as Fig. 7, the welding area is expanded to the entire IP for added rigidity.

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Introduction of Infiniti Q30/QX30 Cockpit Module

Fig. 6 Existing ducted structure welding area

Fig. 7 Q30 ducted structure welding area

3.2. IPMaterialSelection Conventionally, the IP product was made of the polypro-pylene (PP) composites where talc was kneaded (called PPT). The IP in the Q30 is made of the composites where glass fiber (GF) is kneaded to the PP. In detail, a long glass fiber is kneaded for the material composition (called PP+LGF) so that the material characteristics can be enhanced after molding as long as the fiber length is kept. Table 1 shows comparison of material characteristics between the PPT and the PP+LGF. Mainly, the PP+LGF has the following advantage over the PPT:

(1) Higher rigidity(2) Higher heat resistance

Table 1 Characteristic comparison of PPT and PP+LGF

Characteristic PP+LGF PPTFlexual modulus (Mpa) 4450 2140

HDT (℃) 170 120

These characteristics improve the rigidity and heat resistance from the conventional structures. However, adoption of the PP+LGF required solutions for the fol-lowing issues:

(A) Maintaining a remaining fiber length after molding(B) Preventing molding deformation

Fig. 8 outlines that the fiber length has significant in-fluences on the PP+LGF material characteristics and indicates that a certain fiber length must remain to meet required characteristics. Comparing to the PPT, furthermore, molding deformation may typically occur due to anisotropic mold shrinkage with fiber influences.

Fig. 8 Influence of remaining fiber length (image)

3.3. PP+LGFMoldingProcess Fig. 9 summarizes the fiber length which is shortened as the process proceeds from charging the material in the molding machine to injecting in the molds. To mini-mize the cut fiber length, the generally used double flight screw was replaced with a single flight screw. In addi-tion, the grade of the mold steel was changed to prevent from wearing by the fiber.

Fig. 9 Remaining fiber length in molding process (image)

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CALSONIC KANSEI TECHNICAL REVIEW vol.13 2017

To suppress molding deformation, the fiber orientation is optimized by identifying an appropriate gate position and an injection timing from resin flow analysis. In the meantime, the molding conditions are adjusted so that weld is formed at a position where the IP strength is not affected. If deformation is not avoidable with adjusting the molding conditions, the IP shape is contrived.

Fig. 10 Warpage prediction by CAE analysis

4. Vacuum Adhesion Technology4.1. SelectionofProductionMethod

Conventional Infiniti models adopted the IP structure where the skin was formed by powder slush molding and bonded to the substrate with urethane foam (cush-ion layer). Along the recent design trend of lowered and thinned upper pads, the IP in the Q30 is structured with the cushion-layer laminated skin that brings a benefit in minimizing the cushion layer thickness and provides a soft touch feel to customers. This structure allows reduc-tion of approximately 5 mm thickness and form of the product shape in conformity to the style intent. There are generally various production methods for form-ing the laminated skin and bonding to the substrate. The Q30 adopted the “Positive vacuum forming and bonding method” that forms the convex skin shape and bonds to the substrate by vacuuming in one process (Fig. 11).

Fig. 11 Positive Vacuum forming and press process image

4.2.CompatibilityofFormabilityandDesign In the positive vacuum forming and bonding method, because grain-textured skins are stretched to form the convex shape, there are potential risks of failures, such as appearance degradation due to tensile elongation of the grain texture and skin fracture due to excessive elongation during the forming process. To eliminate these risks, the elongation rate is estimated with vacu-um forming CAE analysis. If the analysis result shows a highly elongated area, the product shape and the produc-tion process are modified for uniform elongation. Since the upper IP surface at the passenger side is the most noticeable part to customers, we put great effort into finely adjusting the grain depth and size from the raw skin material for forming the optimum grain texture on product surfaces.

Fig. 12 Vacuum forming CAE analysis

5. Concluding Remarks The CPM development for the Q30 concluded with the highly superior quality product to other entry class pre-mium segments. In the future developments, we will ex-pansively apply the technologies to other vehicle models.

YuuyaMiyazaki