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Update "Hub-Motor-Measurements"

seb 2026-02-28 14:26:32 -05:00
parent d0efabbda8
commit 5cf7dec267
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Hub-Motor-Measurements.md

@ -4,17 +4,21 @@
**Measured by:** Tee (digital caliper) **Measured by:** Tee (digital caliper)
**Motor:** 8" / 10x2.125 hoverboard hub motor (brushless, FOC ESC) **Motor:** 8" / 10x2.125 hoverboard hub motor (brushless, FOC ESC)
## Axle Profile (Stepped / Keyed) ## Axle Profile (Stepped / D-Cut Shaft)
The axle has a **stepped profile** — wider base near the hub, narrower keyed section for dropout clamping. The axle has a **stepped profile** — wider base near the hub, narrower D-cut shaft above.
``` ```
┌─────────┐ ┌─────────┐
│ 15.35 │ ← flat-to-flat (top) │ 3mm │ ← tip / shoulder
├─────────┤
│ │ │ │
│ ø13mm │ ← keyed shaft section │ ø15.95 │ ← D-cut shaft diameter
│ (D-cut │ (flat on one side, 13mm across flat)
│ 13mm │
│ flat) │
│ │ │ │
│ 43.35mm │ ← keyed section length │ 43.35mm │ ← D-cut section length
│ │ │ │
├─────────┤ ├─────────┤
│ ø16mm │ ← base section (measured 16.11mm) │ ø16mm │ ← base section (measured 16.11mm)
@ -22,27 +26,28 @@ The axle has a **stepped profile** — wider base near the hub, narrower keyed s
└─────────┘ └─────────┘
─── hub face ─── ─── hub face ───
Total protrusion: 63.5mm Total protrusion: 65.5mm
``` ```
## Measurements ## Measurements
| # | Dimension | Value | Notes | | # | Dimension | Value | Notes |
|---|-----------|-------|-------| |---|-----------|-------|-------|
| 1 | Axle base diameter | **16.11 mm** | Near hub face | | 1 | Axle base diameter | **16.11 mm** | Round section near hub face |
| 2 | Axle keyed section diameter | **~13 mm** | Narrower upper section | | 2 | D-cut shaft diameter | **15.95 mm** | Round diameter before D-cut |
| 3 | Total axle protrusion | **63.5 mm** | Hub face to tip | | 3 | D-cut flat width | **13 mm** | Across the flat |
| 4 | Keyed section length | **43.35 mm** | Upper shaft only | | 4 | Total axle protrusion | **65.5 mm** | Hub face to tip |
| 5 | Bearing seat OD | **~37.8 mm** | Hub center collar | | 5 | D-cut section length | **43.35 mm** | Upper shaft |
| 6 | Flat-to-flat width | **15.35 mm** | Anti-rotation flats at top | | 6 | Base section length | **15 mm** | Lower stepped portion |
| 7 | Base section length | **15 mm** | Lower stepped portion | | 7 | Tip/shoulder | **3 mm** | Feature at top of shaft |
| 8 | Bearing seat OD | **~37.8 mm** | Hub center collar |
## Tire Specs ## Tire Specs
- Inflate to **35 PSI** (240 kPa / 2.5 BAR) - Inflate to **35 PSI** (240 kPa / 2.5 BAR)
- Size: 10x2.125 pneumatic - Size: 10x2.125 pneumatic
## Design Implications ## Design Implications
- **Dropout clamp** must accommodate stepped profile: 16mm bore at base, 13mm keyed slot above - **Dropout clamp** must accommodate stepped profile: 16mm bore at base, D-cut slot above
- **Anti-rotation** via flats (15.35mm flat-to-flat) — design dropout with matching D-profile - **Anti-rotation** via D-cut flat (13mm across flat on a 15.95mm shaft)
- **Axle length** (63.5mm) gives room for dropout plate + nut + washer - **Axle length** (65.5mm) gives room for dropout plate + nut + washer
- **Bearing seat** (37.8mm OD) — allow clearance on inner face of mount - **Bearing seat** (37.8mm OD) — allow clearance on inner face of mount