Glove box assembly: located in lower middle position of passenger side of dashboard, used to store user manuals, storage items and decorative box assembly.
As shown in Figure 1 below.

 

Glove box door: external parts of glove box that can open and close storage function.
Glove box lock: A system that locks fixed function when glove box is closed.
Glove boxes are classified from form of storage structure, which can generally be divided into two types, namely, tipping bucket type and fixed type, as shown in Figure 2.

 

If glove box door lock mechanism is classified by form, it can be divided into lock hook type and lock pin type.
In addition, glove box door welding process can be divided into friction welding glove box and hot plate welding glove box; from flocking process, it can be divided into flocking glove box and non-flocking glove box; from functional configuration, it can be classified into damping glove box and non-damping glove box.

 

Introduction of typical structure, technology and materials of glove box assembly.
Glove box is generally composed of three parts: glove box door, box (body), and glove box accessories. Glove box door assembly often includes a glove box locking mechanism and a wrench; while glove box accessories include glove box hinges, cushions, single-point lock seats (only single-point locks), damping, and stop positions. Figure 4 is a schematic diagram of some glove boxes.
Due to cost pressure, some glove box designs integrate glove box bucket and IP or co-pilot side lower guard plate into one part, while glove box has only a fixed glove box with a door assembly or a door assembly with a tipping bucket.

 

Appearance and texture of glove box will usually be consistent with dashboard body. If a hard dashboard body is used, then a glove box with a hard outer layer will inevitably be used. If a soft dashboard body is used, then it is possible to use a glove box with a soft outer layer. Material used for glove box door is correspondingly consistent with that of dashboard body. Some boxes with complex structures cannot be directly molded into one piece and also use process of welding multiple plastic parts. Glove box door is generally composed of door outer panel and door inner panel, they can be connected by vibration friction welding, hot plate welding or screws. Some low-end models only use single-layer door outer covers due to cost considerations. In addition, a number of criss-crossing ribs are usually added to inner panel of glove box door to enhance strength of door panel. Glove box door that needs to protect knees of occupant must reach a certain rigidity. Therefore, in order to meet requirements, some models also need to inlay metal plates or foam buffer blocks between inner and outer panels to further absorb energy. In addition, accessories for glove box usually include door hinges, door lock mechanisms, dampers, and glove box lights. Main function of damper is to cushion opening of door, reduce impact and noise during opening. Glove box light is used to illuminate interior of box when user uses it.

 

Storage space of glove box (glove box frame). There are many forms of glove box frames, namely aforementioned fixed and tipping bucket types. So-called fixed type refers to inside of frame body, that is, inner bucket as glove box, that is, storage space is located in dashboard body, as shown in Figure 5 below; while tipping bucket type means that inner bucket and door inner panel are connected as a whole, that is, storage space is on the door, inner bucket turns out together when door is opened. Tipping bucket type is generally more convenient for users to take contents in bucket, but due to need to add a corresponding structure on door inner panel, available space inside glove box will be reduced, which is not conducive to storage of items, and it is also not conducive to arrangement of internal parts such as glove box lights. On the contrary, fixed type can provide a larger space, but it is not convenient for front occupants to take items.

 

In addition, there are two main types of glove box door lock mechanisms: lock hook type and lock pin type. Lock hook type realizes locking by hooking lock hook with lock hook, this mechanism is generally arranged in the center of glove box door. Lock pin type means that a retractable lock pin is arranged on glove box door, which is beneficial to flatness, clearance of glove box door and surrounding instrument panel parts. In addition, because there are pin holes on both sides, handle can be arranged on the side close to driver to make it more convenient for driver to use glove box.

 

Above is an overview of main structure of general glove box. At present, there are some unique vehicle glove box structures on the market. For example, there is a kind of glove box divided into upper and lower parts, each part can be opened and closed separately; another example is some models with relatively low prices directly use inner frame of instrument panel as box body, and inner bucket is directly extended on single-layer outer door. All in all, selection of glove box structure needs to be comprehensively considered based on various factors such as market positioning during design, surface shape of instrument panel, and spatial arrangement of parts.

Outer door panel of glove box is generally made of injection molding. Commonly used materials are PP or PC/ABS. PC/ABS material is a kind of engineering plastics with excellent comprehensive properties. It has high strength, hardness, heat resistance and chemical resistance, but its acoustic properties are poor. PP material has advantages of excellent performance, low density, easy molding, etc., but PP has a slightly poorer wear resistance, greater molding shrinkage, and poor low-temperature performance; because of its low price, it has a higher cost performance. Generally, PP for automobiles has been improved in response to its defects. They are all added with elastomers (EPDM), reinforcing agent talc (TD) or minerals (M mica), and glass fiber (GF). Since PP is a non-polar material, surface treatment (such as flame treatment, spray primer, etc.) is required when painting. Since outer cover of glove box directly faces user, outer cover of glove box of some vehicles requires additional surface treatment. Usual processes include spraying ordinary decorative paint, spraying soft touch paint, and surface covering artificial leather.

Inner panel of glove box door and frame body are generally also injection molded, materials are usually PP and PC/ABS. Although inner door panel and interior of glove box body are not directly visible to user, they are still visible and touchable after user opens glove box. Therefore, flocking technology is usually used for these areas of high-end cars, which can make box feel luxurious, can place stored items in glove box bumping against frame wall to generate noise during driving of car. Flocking is a process for attaching fine fluff to surface of part; generally, it is necessary to apply glue to corresponding part of part in advance, and then spray fluff to corresponding area (manual and electrostatic). Flocking technology is widely used in production process of glove boxes and other storage automotive parts.

 

Glove box door lock mechanism is generally a small assembly of moving parts. Basic form of handle has been mentioned in previous chapter. Generally, middle-mounted handle has a lock to work with its counterpart, and lock is generally a metal stamping part. In addition to claw-type bayonet, sometimes a bullet-type bayonet tongue is also used, bayonet tongue can achieve locking function after being inserted into lock. For two-sided handles, polyoxymethylene is generally used as material for tongue.
Polyoxymethylene (POM), also known as polyoxymethine, has excellent physical and mechanical properties, is known as metal plastic. Polyoxymethylene has excellent flexural strength, creep resistance and fatigue resistance, has a low coefficient of friction against repeated impacts and is resistant to wear. Therefore, it is also widely used in production of motion friction mechanisms for interior parts. Therefore, at two pin holes on door frame corresponding to POM tabs, two POM components (name stop blocks) need to be inserted to work together with tabs, which is more conducive to smooth and comfortable hand feeling of opening and closing glove box door. By the way, shaft pin and clip of glove box door shaft often use POM.
In order to make movement of glove box door even and smooth when it is opened, dampers are also widely used in glove box. Dampers can be roughly divided into two forms according to their working principles: air damping (Figure 7) and silicone oil damping (Figure 8).

 

Air damping is generally a cylindrical buffer cylinder assembly, which relies on air compression to play a buffering role. Silicone oil damping relies on silicone oil to produce resistance. Damping buffers are generally existing assemblies. Suppliers of dampers provide products of different sizes and styles to suit a variety of different glove box products. Function and structure of glove box are briefly introduced above, production process is briefly introduced below. Production process of glove box mainly involves three types of processes: injection molding of parts, welding of inner and outer panels of glove box door, assembly of glove box assembly. In addition, some appearance parts may also involve skin texture, paint spraying, electrostatic flocking, electroplating, etc. Among them, welding and assembling are key to glove box, welding process of glove box will be briefly introduced below. There are two types of welding processes for glove boxes: hot plate welding and vibration friction welding. Welding process of glove box is mainly used to connect inner door and outer door of glove box, so that lock structure of glove box is fixed between inner and outer doors of glove box, so that lock structure is not exposed and achieves a beautiful effect. In addition, double-layer welded glove box door also strengthens structure of door to a certain extent, so as to better protect against knee collisions. Whether it is hot plate welding or vibration friction welding, it is a plastic welding process, its principle is to use heat to soften surface of material and bond it together. Common plastic welding processes mainly include: hot plate welding, vibration friction welding, high frequency welding and ultrasonic welding. Following mainly introduces welding process of lower hot plate. Hot plate welding technologists use electricity to heat metal mold to soften surface of thermoplastic welding process between connected plastics. Hot plate welding is particularly suitable for welding soft semi-crystalline thermoplastics such as PP or PE. Hot plate welding equipment is simple, equipment and mold costs are low. Main disadvantages are long welding cycle and high energy consumption. Product is easily deformed during welding and heating. In addition, when hot plate heats plastic, welding is not firm due to melting of plastic product, or even scorching; in addition, plastic will stick to mold during welding (drawing phenomenon), will emit an unpleasant smell, causing air pollution. Advantage of hot plate welding is that it is easier to design shape of product and welding part.