Rubber hoses used in automobiles are a very common type of hose. These hoses belong to the category of profiled composite rubber hoses, consisting of two layers of rubber with a knitted wire layer sandwiched between them. The manufacturing process for this type of profiled composite hose differs from that of single‑layer straight‑type hoses. For single‑layer straight hoses, a rubber extruder is used to extrude and form the hose, after which it undergoes vulcanization in a hot‑air vulcanizing oven to complete production. In contrast, automotive hoses require two rubber extruders for in‑line extrusion: the first extruder processes the rubber compound, while the second extrudes the outer layer of the hose. The second extruder is equipped with a T‑die to produce the hose; once extruded, the hose passes through water cooling and a release agent bath, then is conveyed by a take‑up unit to a cutting machine for lengthwise trimming. This cuts the hose to the desired length. After being cut to size by the cutting machine, the hose is shaped using a sizing mandrel and then placed in a vulcanizing tank for vulcanization, resulting in the finished product.

1. Product Features

The compound rubber extruder employs cold-feed extrusion, enabling the simultaneous co‑extrusion of two colors using two separate extruders. It is capable of producing two‑color rubber products for applications such as ventilation connectors, rubber winding tubes, and rubber knitted tubes. These products exhibit excellent resistance to aging and ozone, high pressure resistance, flexibility, lightweight construction, superior bendability, minimal deformation, and a smooth, aesthetically pleasing surface.

2. Distinctive Advantages

① The feeding device consists of a feeding seat, a feed roller, a bushing, a splined gear sleeve, and a speed‑ratio gear. The feeding‑section bushing (with a rifled‑thread structure) is made of 38CrMoAIA steel and undergoes nitriding treatment, while the feed roller is surface‑hardened. The feed roller is driven by the reducer’s output shaft via gears, and the speed‑ratio gear exhibits ample strength and durability.

② The gearbox employs hardened‑surface cylindrical gears made of low‑carbon alloy steel, with carburized and quenched gear teeth that have been ground to achieve high precision. The gear pair ensures precise transmission. Power is transmitted via parallel shafts, and the output shaft features a hollow design, allowing the screw to pass through and transmit torque via splines.

3. Equipment Process

The entire production line comprises a chiller, a compound rubber extruder, an elevating water tank, and a compact traction unit equipped with PLC‑based cutting. The equipment can manufacture small‑size rubber hoses, rubber strips, and other products, featuring fully automatic touch‑screen control, an integrated material‑feeding conveyor, and a cut‑off alarm function. It maximizes time and labor savings while minimizing manual intervention, and the extruder can be customized to suit different products and specifications.

Hebei Shuangda Rubber and Plastics Machinery Co., Ltd. is a modern enterprise integrating research and development, manufacturing, and sales of complete sets of extrusion equipment for rubber, silicone, and plastics. The company’s main products include rubber extruders, rubber hose extrusion lines, three‑layer composite sealing strip extrusion lines, silicone sealing strip production lines, plastic sealing strip production lines, plastic profile production lines, plastic pipe production lines, elastomer extruders, and other extrusion equipment, as well as production machinery for engineering seals, automotive seals, wire and cable applications, air‑conditioning hoses, braided hoses, automotive hoses, waterstop strips, and related products.