Specifications
| Parameter | Specification |
|---|---|
| Material | Low-alloy steel AISI 4140 or AISI 8620; carbon steel AISI 1020 on request |
| Process | Silica sol lost wax investment casting + CNC milling, turning, drilling and grinding |
| Tolerance | ISO 8062 CT5-CT6 as-cast; machined pivot bore and tooth flank to +/- 0.02 mm, ISO 2768-f |
| Surface finish | As-cast Ra 6.3 um, ground contact faces Ra 0.8 um, manganese phosphate or black oxide optional |
| Weight range | 0.18 – 0.95 kg per part |
| Heat treatment | Carburise and quench, or quench and temper; case depth 0.4-0.8 mm at 58-62 HRC |
| Inspection | CMM and optical profile check, Rockwell and microhardness case depth, magnetic particle inspection, tensile per ASTM E8 |
Key features
- Near-net-shape casting of the pawl tooth form reduces grinding stock while keeping the root fillet free of tool marks.
- Controlled carburising produces a hard wear case over a tough core, resisting impact when the pawl drops into the parking gear.
- Ground cam contact face at 0.8 um Ra cuts friction and stick-slip in the park actuator mechanism.
- Pivot bore finished to H7 with positional tolerance inside 0.03 mm for repeatable engagement geometry.
- Grain flow follows the lever arm contour, raising bending fatigue strength versus plate flame-cut blanks.
- Shot peening on the tooth root fillet option adds compressive residual stress for extended cycle life.
- Dimensional capability studies maintained on all safety-relevant park lock characteristics.
Applications
- Automatic transmission park lock mechanisms
- Dual clutch transmission parking lock actuators
- Electric drive unit park lock assemblies
- Transfer case and range selector parking systems
- Commercial vehicle and bus transmission park locks
- Service and remanufacturing programmes for transmission repair
Quality & compliance
The park pawl lever is a safety-relevant transmission component and is manufactured under our IATF 16949 certified quality system with full APQP discipline. PPAP level 3 documentation is available, including DFMEA and PFMEA, control plan, MSA, dimensional reports, EN 10204 3.1 material certification, heat treat charts with case depth verification and the PSW. IMDS entries are submitted on request and every part is traceable to its heat lot.
FAQ
Q1. Why choose investment casting for a park pawl lever?
Casting produces the complex tooth and lever geometry in one piece, eliminating welded or riveted assemblies and delivering a continuous grain structure with better fatigue performance through the load path.
Q2. How do you control case depth and core hardness?
We run carburising in monitored atmosphere furnaces and verify case depth and hardness profile on sample coupons from every batch, with microhardness traces included in the PPAP package.
Q3. Can you grind the tooth flank to final size?
Yes. We finish grind the tooth flank and cam contact faces after heat treatment to remove distortion and reach the specified profile tolerance and surface finish.
Q4. What inspection do you perform on each lot?
Each lot receives dimensional CMM inspection, hardness and case depth verification, magnetic particle inspection for surface cracks, and visual checks against agreed acceptance criteria.
Q5. Do you support design optimisation?
Our engineers review your model for castability and can suggest fillet radii, draft and section changes that improve fill, reduce porosity and lower machining cost before tooling is cut.
Q6. How fast can you deliver samples?
Development samples are typically ready in 30-35 days including tooling, with expedited rapid-tooling routes available for urgent prototype programmes.
