{
  "$schema": "https://slfy.solidify.studio/schema/slfy-0.1.schema.json",
  "format": "slfy",
  "version": "0.1",
  "model": {
    "id": "spur-gear-pair",
    "title": "Spur gear pair",
    "summary": "Two spur gears placed by relation: the wheel meshes with the pinion and turns at the ratio of their teeth. Both shafts stand in a base plate.",
    "units": "mm",
    "parameters": [
      {
        "id": "z1",
        "label": "Pinion teeth",
        "symbol": "z_1",
        "value": 18,
        "min": 12,
        "max": 30,
        "step": 1,
        "unit": ""
      },
      {
        "id": "z2",
        "label": "Wheel teeth",
        "symbol": "z_2",
        "value": 42,
        "min": 20,
        "max": 80,
        "step": 1,
        "unit": ""
      },
      {
        "id": "m",
        "label": "Module",
        "symbol": "m",
        "value": 3,
        "min": 1,
        "max": 6,
        "step": 0.5,
        "unit": "mm"
      },
      {
        "id": "N1",
        "label": "Pinion speed",
        "symbol": "N_1",
        "value": 600,
        "min": 0,
        "max": 1500,
        "step": 10,
        "unit": "rpm"
      }
    ],
    "parts": [
      {
        "id": "base",
        "name": "Base plate",
        "material": "castIron",
        "role": "housing",
        "explode": [
          0,
          0.14,
          0
        ],
        "info": {
          "summary": "The frame both shafts stand in, so the gears are held at their centre distance."
        },
        "mount": {
          "kind": "against",
          "target": "pinion",
          "face": "-y",
          "shift": [
            "m * (z1 + z2) / 4000",
            0,
            0
          ]
        },
        "shapes": [
          {
            "kind": "box",
            "sx": "m * (z1 + z2) / 2000 + m * z2 / 2000 + 0.06",
            "sy": 0.01,
            "sz": "m * z2 / 1000 + 0.04"
          }
        ]
      },
      {
        "id": "pinion",
        "name": "Pinion",
        "material": "steel",
        "role": "moving",
        "explode": [
          0,
          0,
          0.1
        ],
        "info": {
          "summary": "The driving gear. Only the driver has a motion; the wheel turns because it meshes."
        },
        "motion": {
          "kind": "rotate",
          "axis": "y",
          "speed": "N1 * 2 * pi / 60 / 20"
        },
        "shapes": [
          {
            "kind": "gear",
            "rInner": 0.008,
            "h": 0.02,
            "teeth": "z1",
            "module": "m / 1000"
          }
        ],
        "children": [
          {
            "id": "pinion_shaft",
            "name": "Pinion shaft",
            "material": "steelDark",
            "role": "moving",
            "shapes": [
              {
                "kind": "cylinder",
                "r": 0.008,
                "h": 0.05
              }
            ]
          }
        ]
      },
      {
        "id": "wheel",
        "name": "Wheel",
        "material": "bronze",
        "role": "moving",
        "explode": [
          0,
          0,
          0.1
        ],
        "info": {
          "summary": "The driven gear: its centre is the sum of the two pitch radii from the pinion's."
        },
        "mount": {
          "kind": "mesh",
          "target": "pinion",
          "side": "+x"
        },
        "shapes": [
          {
            "kind": "gear",
            "rInner": 0.01,
            "h": 0.02,
            "teeth": "z2",
            "module": "m / 1000"
          }
        ],
        "children": [
          {
            "id": "wheel_shaft",
            "name": "Wheel shaft",
            "material": "steelDark",
            "role": "moving",
            "shapes": [
              {
                "kind": "cylinder",
                "r": 0.01,
                "h": 0.05
              }
            ]
          }
        ]
      }
    ],
    "calculations": [
      {
        "id": "i",
        "label": "Gear ratio",
        "symbol": "i",
        "formula": "z2 / z1",
        "unit": "",
        "latex": "i = \\frac{z_2}{z_1}"
      },
      {
        "id": "N2",
        "label": "Wheel speed",
        "symbol": "N_2",
        "formula": "N1 / i",
        "unit": "rpm",
        "latex": "N_2 = \\frac{N_1}{i}"
      },
      {
        "id": "a",
        "label": "Centre distance",
        "symbol": "a",
        "formula": "m * (z1 + z2) / 2",
        "unit": "mm",
        "latex": "a = \\frac{m (z_1 + z_2)}{2}"
      }
    ]
  },
  "view": {
    "camera": {
      "position": [
        0.18,
        0.22,
        0.26
      ],
      "target": [
        0.045,
        0,
        0
      ]
    },
    "extent": 0.3,
    "floorY": -0.07,
    "cut": {
      "enabled": false,
      "normal": [
        0,
        0,
        1
      ],
      "pos": 0
    }
  },
  "meta": {
    "generator": "Solidify (solidify.studio)",
    "license": "CC-BY-4.0",
    "created": "2026-11-10"
  }
}