The air suspension control arm bracket body ties the trailing or leading control arm to the air spring and the height control linkage on a bus, coach or truck air ride suspension. It carries the air spring seat. It also carries the arm pivot bush and the height sensor or levelling valve mount. Moreover, it is loaded in every direction as the axle articulates over rough road. Fabricated brackets crack at the seat-to-gusset weld under constant articulation, and plate-cut versions need four or five pieces welded together with a fixture to hold alignment. Ningbo Ruican casts the bracket as one body in EN-GJS-450-10 with a cored air line passage and integrated sensor boss, then machines the bush bore and spring seat in a single datumed setup.
Specifications
| Parameter | Specification |
|---|---|
| Casting process | Silica sol lost wax investment casting with ceramic core for the air line passage; water glass route available for aftermarket service volumes |
| Material options | EN-GJS-450-10 ductile iron; EN-GJS-500-7 and EN-GJS-600-3 available to drawing |
| Dimensional tolerance (ISO 8062-3 CT grade) | CT6 as cast; CT5 after machining; CT4 held on the pivot bush bore, spring seat face and sensor mounting datum |
| Machining | CNC turning of the pivot bush bore, 4-axis CNC milling of the spring seat and sensor face, drilling and tapping of mounting and airline port threads |
| Surface finish (Ra) | Ra 3.2 um machined on the spring seat and mounting faces; Ra 1.6 um on the pivot bush bore |
| Weight range | 1.4 kg to 6.8 kg per bracket depending on axle rating |
| Typical lead time | Tooling 5-6 weeks; first article 3-4 weeks after tooling; production 6-8 weeks |
Key features
- One-piece body replaces a four-piece welded bracket, removing three welds and the alignment fixture needed to hold the spring seat to the bush axis.
- Ceramic-cored air line passage removes a drilling operation and the external hose routing that chafes against the frame on fabricated designs.
- EN-GJS-450-10 gives 450 MPa tensile strength with at least 10 percent elongation and high impact toughness, which is what the bracket needs at low ambient temperature.
- Pivot bush bore machined to H7 with cylindricity within 0.03 mm, keeping the bush pressed in square so the arm articulates without walking.
- Spring seat face machined flat within 0.05 mm and square to the bush axis within 0.10 mm, preventing the air spring from rolling off its seat under full bump.
- Cast-in sensor boss and height control mounting pads remove two brackets and their fasteners from the bill of material and from the assembly line.
- Charpy impact values are reported for the grade at minus 20 C where the drawing specifies it, supporting cold climate service on northern routes.
Applications
- Bus and coach front and rear air suspension control arm brackets.
- Truck and tractor air ride rear suspension trailing arm brackets.
- Trailer and semi-trailer air suspension hanger brackets.
- Moreover, Height control valve and levelling sensor mounting brackets.
- Cab suspension and seat air spring mounting brackets for commercial vehicles.
- Special vehicle and motorhome air suspension retrofit bracket sets.
Quality & compliance
Ningbo Ruican casts and machines to IATF 16949 and works to ISO 9001, issuing EN 10204 3.1 material certification with every shipment. PPAP Level 3 and FAIR packages are available on request, built from the customer’s ballooned drawing and submission template. Heat lot traceability runs from the melt through heat treatment to the finished bracket, and each lot carries nodularity and ferrite records, a hardness survey and a dimensional report on all ballooned features. Fatigue, impact and salt-spray testing are performed to the customer’s drawing specification and acceptance criteria.
FAQ
Can you work from a sample bracket?
Yes. We reverse scan a sample bracket or a welded assembly, build the 3D model and return it for approval with a DFM review covering coring of the air passage, gating position and machining allowance. Generally, production tooling is cut only after the model and datum scheme are approved.
What is the minimum order quantity?
Pilot quantities from 20 pieces can be produced from one tooling set for validation and vehicle testing. We move to multi-cavity tooling when volume justifies it. Additionally, repeat orders run from maintained tooling and we can hold agreed safety stock against a released schedule.
Do you support PPAP submission?
Yes. We support PPAP Level 3 including dimensional results for every ballooned feature, material and hardness test results, control plan, process flow diagram, PFMEA and capability study on the characteristics you designate. In general, your own submission templates can be used with the evidence attached.
Can you machine the bracket fully in-house?
Machining is fully in-house, covering bush bore turning, spring seat and sensor face milling on 4-axis machines, and all drilling and tapping. Also, internally built fixtures keep machining and inspection datums identical. The first article report matches what the assembly line actually sees.
Do you supply heat treatment and coating?
We supply brackets in the as-cast, ferritised or stress-relieved condition the drawing specifies, with furnace charts and hardness survey in the documentation package. Protective finishes including e-coat, powder coat and zinc-rich primer can be applied to the customer’s specification and salt spray tested to their acceptance criteria.
CTA
Send your air suspension control arm bracket drawing, sample or 3D model for a DFM review, coring proposal and a tooling plus piece price quotation. Contact Wendy She — sales@cnsandcasting.com — WhatsApp +86-13777124360, or visit https://cnsandcasting.com to start your program with Ningbo Ruican.
