Log
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doneI've built the final drive with its open bevel-gear differential. It has 39 parts, measures about 828 × 350 × 200 mm, and all the results come out as expected.
**What's in the model**
- **Drive pinion** (goldenrod) on the input shaft, with a drive flange, coming in from the front.
- **Ring gear** (bronze), 41 teeth on a 200 mm pitch diameter. It's bolted with 8 bolts to the cage flange.
- **Cage**: an open frame of four steel-blue bars with an end plate, the ring flange and two hubs. The hubs turn in two silver bearings.
- **Cross pin** carrying the two **spider gears** (firebrick). These mesh with the two **side gears** (copper).
- **Half shafts** leaving left and right. Each ends in a flange with an orange marker, so you can see how far each one has turned.
- **Gears**: each bevel gear is a cone frustum with a black zig-zag tooth line on its face. The cones are sized so each meshing pair has true pitch cones: ring 75°/pinion 15°, side 58°/spider 32°.
**Results at the default inputs**
| Result | Value |
|---|---|
| Final-drive ratio | 3.727 |
| Cage speed | 536.6 rpm |
| Left half shaft (inner, 12 m left bend) | 501.9 rpm |
| Right half shaft (outer) | 571.2 rpm |
| Spider speed about its pin | 55.4 rpm |
| Torque on each half shaft | 559.1 N m |
| Road speed | 62.7 km/h |
| Tractive force at each wheel | 1803.5 N |
Each result is a computed slot of the model with its unit in the doc string.
**Inputs you can change** (Inputs panel)
| Input | Range |
|---|---|
| Pinion teeth | 8–15 |
| Ring gear teeth | 35–47 |
| Ring gear pitch diameter | 170–260 mm |
| Side gear teeth | 14–22 |
| Spider gear teeth | 10–14 |
| Input torque | 0–600 N m |
| Input speed | 0–6000 rpm |
| Track | 1200–1800 mm |
| Dynamic tyre radius | 250–400 mm |
**The two STATE inputs move the parts:**
- **pinion-angle-deg** (−1440 to 1440): turns the pinion. The ring gear, cage, cross pin and bolts turn by that angle divided by the ratio.
- **corner-radius-m** (−60 to 60; positive is a left bend, 0 is straight ahead): each half shaft turns by the cage angle × (1 ∓ half-track ÷ radius). The spiders roll on their pin by the difference × side teeth ÷ spider teeth. Going straight, the spiders stand still relative to the cage.
**Limits**
- The engine has no boolean operations, so nothing is cut: teeth are drawn lines, not real tooth forms, and the bearings and hubs are drawn as hollow rings.
- The torque figures assume no losses.
- The half shafts are shortened stubs about 400 mm long, not full track width.
- A corner radius smaller than half the track (under about 0.8 m) makes the inner shaft turn backwards. That is right for the equations, but it isn't a realistic bend.
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textThe cone draws radius-1 at its rear end, so the gear bodies came out reversed. I'll swap the two radii.
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textThe model builds and the numbers check out. Next I'll render it to confirm the gear placement and meshing.
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tool-errorwrite_model: Error compiling or loading the model file:
No such toplevel define-object keyword exists as (PL-CA8AE5073FF2::CAGE-PLATE-LEFT :TYPE 'CYLINDER :CENTER (MAKE-POINT -48 0 0) :ORIENTATION (ALIGNMENT :REAR (THE PL-CA8AE5073FF2::XV)) :LENGTH 6 :RADIUS 58 :INNER-RADIUS 24 :NUMBER-OF-SECTIONS 4 :DISPLAY-CONTROLS (LIST :COLOR :STEEL-BLUE)).
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tooldescribe_object
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promptA final drive with an open bevel-gear differential. Parts: the drive pinion on the input shaft, the ring (crown) gear bolted to the differential cage, the cage turning in two bearings, a cross pin in the cage carrying two spider bevel gears, two side gears meshing with the spiders, and the two half shafts leaving left and right. Draw each bevel gear as a cone frustum carrying visible tooth marks, and the cage as an open frame so the gears inside can be seen. Inputs: pinion teeth 11, ring gear teeth 41, ring gear pitch diameter 200 mm, side gear teeth 16, spider gear teeth 10, input torque 300 N m, input speed 2000 rpm, track 1550 mm, dynamic tyre radius 310 mm, and the STATE inputs pinion-angle-deg and corner-radius-m (the radius of the bend the car is taking, measured to the middle of the axle, positive for a left-hand bend; 0 means straight ahead; default 12). The cage turns by the pinion angle divided by the final-drive ratio; in a bend the outer half shaft turns faster and the inner slower by the same amount, and the spider gears roll on their pin to allow it. Compute: final-drive ratio, cage speed, left and right half-shaft speeds in rpm, spider gear speed about its pin, the torque on each half shaft (equal, as an open differential gives), the road speed in km/h, and the tractive force at each wheel in N.
(This prompt was written by Claude, Anthropic's AI model, as one entry in a catalog of simulative models of automotive systems.) House brief: key dimensions and operating values are root inputs with input-controls (ranges the model holds at); STATE inputs must really move the parts; each result named above is a computed-slot of MODEL with a doc string giving its unit; simplified but recognisable geometry, about 15 to 80 leaves; colours only from Gendl's own table, hyphenated: :steel-blue, :slate-gray, :dim-gray, :silver, :brass, :copper, :bronze, :firebrick, :goldenrod, :orange, :red, :black, :dark-olive-green.
noteSession ca8ae5073ff2 opened for an external agent.