{
  "schema_version": "hardware-structure/v2",
  "unit": "mm",
  "product_id": "smart-ring",
  "title": "智能戒指结构评审",
  "revision": "engineering-fit-r2-20261016",
  "updated_at": "2026-10-16",
  "coordinate_system": "X/Y=戒指径向平面，Z=戒宽；原点位于环体中心",
  "envelope": {
    "external": {
      "width": 30,
      "depth": 10,
      "height": 30,
      "center": [
        0,
        0,
        0
      ]
    },
    "internal": {
      "width": 22,
      "depth": 7,
      "height": 12,
      "center": [
        0,
        9,
        0
      ]
    },
    "wall_thickness": 1.2
  },
  "openings": [
    {
      "id": "optical-inner",
      "label": "内圈光学窗",
      "center": [
        0,
        -10.5,
        0
      ],
      "axis": [
        0,
        1,
        0
      ],
      "width": 7,
      "height": 4,
      "alignment_tolerance_mm": 0.2
    },
    {
      "id": "charge-left",
      "label": "左充电触点孔",
      "center": [
        -3,
        12.3,
        -4.1
      ],
      "axis": [
        0,
        0,
        -1
      ],
      "diameter": 1.4,
      "alignment_tolerance_mm": 0.15
    },
    {
      "id": "charge-right",
      "label": "右充电触点孔",
      "center": [
        3,
        12.3,
        -4.1
      ],
      "axis": [
        0,
        0,
        -1
      ],
      "diameter": 1.4,
      "alignment_tolerance_mm": 0.15
    }
  ],
  "parts": [
    {
      "id": "outer-band",
      "label": "钛合金外圈",
      "group": "shell",
      "type": "ring_segment",
      "dimensions": {
        "outer_diameter": 30,
        "inner_diameter": 28,
        "width": 9.5,
        "arc_deg": 300
      },
      "position": [
        0,
        0,
        0
      ],
      "rotation_deg": [
        0,
        0,
        120
      ],
      "explode_vector": [
        0,
        0,
        1
      ],
      "material": "喷砂钛合金",
      "quantity": 1,
      "source_status": "design_proposed",
      "source_reference": "2026-10-16 工程装配修订；尺寸为 design_proposed，见 engineering_update.source_constraints，非供应商 CAD 或实物确认。",
      "section_profile": "rectangular",
      "geometry_representation": "nominal_rectangular_annular_volume"
    },
    {
      "id": "inner-liner",
      "label": "贴肤内衬",
      "group": "shell",
      "type": "ring_segment",
      "dimensions": {
        "outer_diameter": 23.2,
        "inner_diameter": 20,
        "width": 8.8,
        "arc_deg": 320
      },
      "position": [
        0,
        0,
        0
      ],
      "rotation_deg": [
        0,
        0,
        290
      ],
      "explode_vector": [
        0,
        0,
        -1
      ],
      "material": "皮肤接触聚合物候选；生物相容性及汗液验证待完成",
      "quantity": 1,
      "source_status": "design_proposed",
      "source_reference": "2026-10-16 工程装配修订；尺寸为 design_proposed，见 engineering_update.source_constraints，非供应商 CAD 或实物确认。",
      "section_profile": "rectangular",
      "geometry_representation": "nominal_rectangular_annular_volume"
    },
    {
      "id": "crown",
      "label": "顶部电子冠",
      "group": "shell",
      "type": "rounded_frame",
      "dimensions": {
        "width": 11,
        "height": 4,
        "depth": 7.2,
        "corner_radius": 1.5,
        "frame_width": 0.7
      },
      "position": [
        0,
        12.4,
        0
      ],
      "rotation_deg": [
        0,
        0,
        0
      ],
      "explode_vector": [
        0,
        1,
        0
      ],
      "material": "非金属 RF 窗口及内载架；材料待 RF/皮肤接触验证",
      "quantity": 1,
      "source_status": "design_proposed",
      "source_reference": "2026-10-16 工程装配修订；尺寸为 design_proposed，见 engineering_update.source_constraints，非供应商 CAD 或实物确认。"
    },
    {
      "id": "main-pcba",
      "label": "超薄主控板",
      "group": "pcb",
      "type": "box",
      "dimensions": {
        "width": 9,
        "height": 0.8,
        "depth": 5
      },
      "position": [
        0,
        12.3,
        0
      ],
      "rotation_deg": [
        0,
        0,
        0
      ],
      "explode_vector": [
        0,
        0.5,
        0
      ],
      "material": "Rigid-flex HDI",
      "quantity": 1,
      "source_status": "design_proposed",
      "source_reference": "2026-10-16 工程装配修订；尺寸为 design_proposed，见 engineering_update.source_constraints，非供应商 CAD 或实物确认。",
      "inside_envelope": true
    },
    {
      "id": "battery",
      "label": "弧形电池包络",
      "group": "sensor",
      "type": "ring_segment",
      "dimensions": {
        "outer_diameter": 27.2,
        "inner_diameter": 23.4,
        "width": 6.9,
        "arc_deg": 132
      },
      "position": [
        0,
        0,
        0
      ],
      "rotation_deg": [
        0,
        0,
        120
      ],
      "explode_vector": [
        0,
        0.7,
        0
      ],
      "material": "锂聚合物",
      "quantity": 1,
      "source_status": "design_proposed",
      "source_reference": "2026-10-16 工程装配修订；尺寸为 design_proposed，见 engineering_update.source_constraints，非供应商 CAD 或实物确认。",
      "envelope_allowance": {
        "candidate_nominal_radial_thickness_mm": 1.7,
        "candidate_nominal_axial_width_mm": 6.5,
        "radial_allowance_mm": 0.2,
        "axial_allowance_mm": 0.4,
        "authority": "published candidate family only; exact variant drawing and swelling specification still required"
      },
      "section_profile": "rectangular",
      "geometry_representation": "conservative_installation_envelope_not_supplier_cad"
    },
    {
      "id": "optical-module",
      "label": "PPG 组合件预留区（发射器、接收器和隔墙见实体）",
      "group": "sensor",
      "type": "box",
      "dimensions": {
        "width": 6.8,
        "depth": 3.5,
        "height": 2.2
      },
      "position": [
        0,
        -10.5,
        0
      ],
      "rotation_deg": [
        0,
        0,
        0
      ],
      "explode_vector": [
        0,
        -1,
        0
      ],
      "material": "光学封装",
      "quantity": 1,
      "source_status": "design_proposed",
      "source_reference": "2026-10-16 工程装配修订；尺寸为 design_proposed，见 engineering_update.source_constraints，非供应商 CAD 或实物确认。",
      "opening_id": "optical-inner",
      "render_mode": "metadata_only"
    },
    {
      "id": "optical-fov",
      "label": "贴肤检测光路",
      "group": "fov",
      "type": "lens",
      "dimensions": {
        "diameter": 5,
        "length": 8
      },
      "position": [
        0,
        -6,
        0
      ],
      "rotation_deg": [
        0,
        0,
        0
      ],
      "explode_vector": [
        0,
        0,
        0
      ],
      "material": "虚拟光路",
      "quantity": 1,
      "source_status": "design_proposed",
      "source_reference": "PPG optical path proposal"
    },
    {
      "id": "charge-left-contact",
      "label": "左充电触点",
      "group": "interface",
      "type": "cylinder",
      "dimensions": {
        "diameter": 1.2,
        "length": 1.8
      },
      "position": [
        -3,
        12.3,
        -4.1
      ],
      "rotation_deg": [
        90,
        0,
        0
      ],
      "explode_vector": [
        0,
        0,
        -1
      ],
      "material": "镀金铜",
      "quantity": 1,
      "source_status": "design_proposed",
      "source_reference": "2026-10-16 工程装配修订；尺寸为 design_proposed，见 engineering_update.source_constraints，非供应商 CAD 或实物确认。",
      "opening_id": "charge-left"
    },
    {
      "id": "charge-right-contact",
      "label": "右充电触点",
      "group": "interface",
      "type": "cylinder",
      "dimensions": {
        "diameter": 1.2,
        "length": 1.8
      },
      "position": [
        3,
        12.3,
        -4.1
      ],
      "rotation_deg": [
        90,
        0,
        0
      ],
      "explode_vector": [
        0,
        0,
        -1
      ],
      "material": "镀金铜",
      "quantity": 1,
      "source_status": "design_proposed",
      "source_reference": "2026-10-16 工程装配修订；尺寸为 design_proposed，见 engineering_update.source_constraints，非供应商 CAD 或实物确认。",
      "opening_id": "charge-right"
    },
    {
      "id": "flex-interconnect",
      "label": "环形柔性互连",
      "group": "interface",
      "type": "ring_segment",
      "dimensions": {
        "outer_diameter": 27.8,
        "inner_diameter": 27.4,
        "width": 5.8,
        "arc_deg": 300
      },
      "position": [
        0,
        0,
        0
      ],
      "rotation_deg": [
        0,
        0,
        120
      ],
      "explode_vector": [
        0,
        0,
        0.5
      ],
      "material": "柔性PI电路",
      "quantity": 1,
      "source_status": "design_proposed",
      "source_reference": "2026-10-16 工程装配修订；尺寸为 design_proposed，见 engineering_update.source_constraints，非供应商 CAD 或实物确认。",
      "allowed_contacts": [
        "outer-band",
        "inner-liner",
        "crown",
        "main-pcba",
        "battery",
        "optical-module",
        "charge-left-contact",
        "charge-right-contact"
      ],
      "section_profile": "rectangular",
      "geometry_representation": "conservative_installation_envelope_not_supplier_cad"
    },
    {
      "id": "green-led-left",
      "label": "绿光LED左",
      "group": "sensor",
      "type": "cylinder",
      "dimensions": {
        "diameter": 1.1,
        "length": 0.8
      },
      "position": [
        -2,
        -10.2,
        0
      ],
      "rotation_deg": [
        0,
        0,
        0
      ],
      "explode_vector": [
        0,
        -1,
        0
      ],
      "material": "光学发射器",
      "quantity": 1,
      "source_status": "design_proposed",
      "source_reference": "2026-10-16 工程装配修订；尺寸为 design_proposed，见 engineering_update.source_constraints，非供应商 CAD 或实物确认。"
    },
    {
      "id": "green-led-right",
      "label": "绿光LED右",
      "group": "sensor",
      "type": "cylinder",
      "dimensions": {
        "diameter": 1.1,
        "length": 0.8
      },
      "position": [
        2,
        -10.2,
        0
      ],
      "rotation_deg": [
        0,
        0,
        0
      ],
      "explode_vector": [
        0,
        -1,
        0
      ],
      "material": "光学发射器",
      "quantity": 1,
      "source_status": "design_proposed",
      "source_reference": "2026-10-16 工程装配修订；尺寸为 design_proposed，见 engineering_update.source_constraints，非供应商 CAD 或实物确认。"
    },
    {
      "id": "photodiode",
      "label": "贴肤光电二极管",
      "group": "sensor",
      "type": "cylinder",
      "dimensions": {
        "diameter": 1.8,
        "length": 0.8
      },
      "position": [
        0,
        -10.2,
        0
      ],
      "rotation_deg": [
        0,
        0,
        0
      ],
      "explode_vector": [
        0,
        -1,
        0
      ],
      "material": "光学接收器",
      "quantity": 1,
      "source_status": "design_proposed",
      "source_reference": "2026-10-16 工程装配修订；尺寸为 design_proposed，见 engineering_update.source_constraints，非供应商 CAD 或实物确认。"
    },
    {
      "id": "temperature-sensor",
      "label": "贴肤温度传感点",
      "group": "sensor",
      "type": "cylinder",
      "dimensions": {
        "diameter": 1.5,
        "length": 0.7
      },
      "position": [
        6.5,
        -8.2,
        0
      ],
      "rotation_deg": [
        0,
        0,
        0
      ],
      "explode_vector": [
        0.4,
        -1,
        0
      ],
      "material": "温度传感器封装",
      "quantity": 1,
      "source_status": "design_proposed",
      "source_reference": "2026-10-16 工程装配修订；尺寸为 design_proposed，见 engineering_update.source_constraints，非供应商 CAD 或实物确认。"
    },
    {
      "id": "ring-retainer-front",
      "label": "可拆轴向绝缘端环 front",
      "group": "bracket",
      "type": "ring_segment",
      "dimensions": {
        "outer_diameter": 28.4,
        "inner_diameter": 23.2,
        "width": 0.6,
        "arc_deg": 300
      },
      "position": [
        0,
        0,
        4.15
      ],
      "rotation_deg": [
        0,
        0,
        120
      ],
      "explode_vector": [
        0,
        0,
        1
      ],
      "material": "工程设计建议材料；牌号、尺寸公差与供货待确认",
      "quantity": 1,
      "source_status": "design_proposed",
      "source_reference": "2026-10-16 engineering-fit proposal; not vendor CAD or physical verification",
      "section_profile": "rectangular",
      "geometry_representation": "nominal_rectangular_annular_volume"
    },
    {
      "id": "ring-retainer-rear",
      "label": "可拆轴向绝缘端环 rear",
      "group": "bracket",
      "type": "ring_segment",
      "dimensions": {
        "outer_diameter": 28.4,
        "inner_diameter": 23.2,
        "width": 0.6,
        "arc_deg": 300
      },
      "position": [
        0,
        0,
        -4.15
      ],
      "rotation_deg": [
        0,
        0,
        120
      ],
      "explode_vector": [
        0,
        0,
        1
      ],
      "material": "工程设计建议材料；牌号、尺寸公差与供货待确认",
      "quantity": 1,
      "source_status": "design_proposed",
      "source_reference": "2026-10-16 engineering-fit proposal; not vendor CAD or physical verification",
      "section_profile": "rectangular",
      "geometry_representation": "nominal_rectangular_annular_volume"
    },
    {
      "id": "optical-light-barrier",
      "label": "发射/接收遮光隔墙（两片）",
      "group": "bracket",
      "type": "box",
      "dimensions": {
        "width": 0.3,
        "height": 1.5,
        "depth": 3.5
      },
      "position": [
        -1,
        -10.7,
        0
      ],
      "rotation_deg": [
        0,
        0,
        0
      ],
      "explode_vector": [
        0,
        0,
        1
      ],
      "material": "黑色不透光聚合物；消光与贴肤密封待测",
      "quantity": 1,
      "source_status": "design_proposed",
      "source_reference": "2026-10-16 engineering-fit proposal; not vendor CAD or physical verification"
    },
    {
      "id": "optical-light-barrier-right",
      "label": "发射/接收遮光隔墙右片",
      "group": "bracket",
      "type": "box",
      "dimensions": {
        "width": 0.3,
        "height": 1.5,
        "depth": 3.5
      },
      "position": [
        1,
        -10.7,
        0
      ],
      "rotation_deg": [
        0,
        0,
        0
      ],
      "explode_vector": [
        0,
        0,
        1
      ],
      "material": "黑色不透光聚合物；消光与贴肤密封待测",
      "quantity": 1,
      "source_status": "design_proposed",
      "source_reference": "2026-10-16 engineering-fit proposal; not vendor CAD or physical verification"
    }
  ],
  "relations": [
    {
      "id": "ppg-axis",
      "type": "optical_angle",
      "part_ids": [
        "optical-module",
        "optical-fov"
      ],
      "axis_a": [
        0,
        1,
        0
      ],
      "axis_b": [
        0,
        1,
        0
      ],
      "expected_deg": 0,
      "tolerance_deg": 1,
      "description": "PPG 光轴垂直指向皮肤"
    },
    {
      "id": "pcb-crown",
      "type": "clearance",
      "part_ids": [
        "main-pcba",
        "crown"
      ],
      "clearance_mm": 1.0,
      "description": "主板与电子冠内壁间隙"
    }
  ],
  "engineering_boundary": "2026-10-16 工程装配提案：已修正列出的名义几何矛盾并建立可执行空间校验。所有新增/改动尺寸为 design_proposed；不是供应商原生 CAD，不证明公差、材料、强度、热、密封、射频、传感性能或量产放行。现有概念照片仅保留为外观参考，后续需供应商图纸和样机验证。",
  "assemblies": [
    {
      "id": "exterior",
      "label": "外观与承力结构",
      "part_ids": [
        "outer-band",
        "inner-liner",
        "crown"
      ]
    },
    {
      "id": "electronics",
      "label": "电子与功能模组",
      "part_ids": [
        "main-pcba",
        "battery",
        "optical-module",
        "green-led-left",
        "green-led-right",
        "photodiode",
        "temperature-sensor"
      ]
    },
    {
      "id": "interfaces",
      "label": "接口、线缆与工作路径",
      "part_ids": [
        "optical-fov",
        "charge-left-contact",
        "charge-right-contact",
        "flex-interconnect"
      ]
    },
    {
      "id": "engineering-fit-components",
      "label": "2026-10-16 装配修订实体零件",
      "part_ids": [
        "ring-retainer-front",
        "ring-retainer-rear",
        "optical-light-barrier",
        "optical-light-barrier-right"
      ]
    }
  ],
  "patterns": [],
  "interfaces": [
    {
      "id": "interface-01",
      "part_id": "charge-left-contact",
      "opening_id": "charge-left",
      "purpose": "左充电触点"
    },
    {
      "id": "interface-02",
      "part_id": "charge-right-contact",
      "opening_id": "charge-right",
      "purpose": "右充电触点"
    },
    {
      "id": "interface-03",
      "part_id": "flex-interconnect",
      "opening_id": null,
      "purpose": "环形柔性互连"
    },
    {
      "id": "ring-ppg-window",
      "part_ids": [
        "inner-liner",
        "green-led-left",
        "green-led-right",
        "photodiode",
        "optical-light-barrier",
        "optical-light-barrier-right"
      ],
      "purpose": "内衬底部保留 40° 光学开口；LED/PD 之间黑色隔墙，禁止把整块光学包络当实体芯片。",
      "status": "design_proposed",
      "optical_axis": [
        0,
        1,
        0
      ]
    },
    {
      "id": "ring-rf-window",
      "part_ids": [
        "outer-band",
        "crown",
        "main-pcba"
      ],
      "purpose": "金属外圈 60° 非闭合窗口供 BLE/NFC 天线研究；这是几何预留，天线匹配/戴手效率尚未验证。",
      "status": "design_proposed"
    }
  ],
  "cables": [],
  "assembly_steps": [
    {
      "id": "step-02",
      "sequence": 2,
      "label": "电子与功能模组",
      "part_ids": [
        "main-pcba",
        "battery",
        "optical-module",
        "green-led-left",
        "green-led-right",
        "photodiode",
        "temperature-sensor"
      ],
      "direction": [
        0,
        1,
        0
      ],
      "status": "design_proposed"
    },
    {
      "id": "step-03",
      "sequence": 3,
      "label": "接口、线缆与工作路径",
      "part_ids": [
        "optical-fov",
        "charge-left-contact",
        "charge-right-contact",
        "flex-interconnect"
      ],
      "direction": [
        0,
        0,
        1
      ],
      "status": "pending_verification"
    },
    {
      "id": "step-04",
      "sequence": 4,
      "label": "外观与承力结构",
      "part_ids": [
        "outer-band",
        "inner-liner",
        "crown"
      ],
      "direction": [
        0,
        1,
        0
      ],
      "status": "design_proposed"
    },
    {
      "id": "engineering-step-4",
      "sequence": 4,
      "label": "将电芯/FPC 置于 11.65–13.95 mm 径向腔，固定电池极耳；装非金属内载架并进行光学、充电与 RF 测试，再装两侧绝缘端环。",
      "part_ids": [
        "battery",
        "flex-interconnect",
        "crown",
        "ring-retainer-front",
        "ring-retainer-rear"
      ],
      "direction": [
        0,
        0,
        1
      ],
      "status": "design_proposed"
    }
  ],
  "validation_rules": [
    {
      "id": "internal-envelope-rule",
      "type": "inside_envelope",
      "severity": "error"
    },
    {
      "id": "opening-alignment-rule",
      "type": "opening_alignment",
      "severity": "error"
    },
    {
      "id": "service-direction-rule",
      "type": "assembly_direction",
      "severity": "warning"
    },
    {
      "id": "crown-board-cavity-fit",
      "type": "part_inside_cavity",
      "cavity_id": "crown-board-cavity",
      "part_ids": [
        "main-pcba"
      ],
      "minimum_clearance_mm": 0.2,
      "severity": "error",
      "evaluator": "scripts/verify_priority_structure_geometry.py"
    },
    {
      "id": "ring-radial-stack",
      "type": "ring_radial_stack",
      "severity": "error",
      "evaluator": "scripts/verify_priority_structure_geometry.py",
      "minimum_radial_clearance_mm": 0.1,
      "minimum_axial_clearance_mm": 0.3
    }
  ],
  "dimension_sources": [
    {
      "id": "confirmed-inputs",
      "status": "customer_confirmed",
      "scope": "客户已确认的产品目标尺寸",
      "reference": "项目需求基线"
    },
    {
      "id": "supplier-mechanical",
      "status": "supplier_drawing",
      "scope": "器件与连接器机械包络",
      "reference": "候选器件机械图"
    },
    {
      "id": "design-values",
      "status": "design_proposed",
      "scope": "外壳、支架与空间关系",
      "reference": "结构设计建议"
    },
    {
      "id": "physical-verification",
      "status": "pending_verification",
      "scope": "公差、材料和装配可靠性",
      "reference": "样机实测待完成"
    },
    {
      "id": "public-analog-references",
      "status": "design_proposed",
      "scope": "公开成品、拆解和社区资料只用于同类结构推导，不构成本项目确认尺寸",
      "reference": "SR-OFFICIAL-01, SR-TEARDOWN-01, SR-COMMUNITY-01"
    },
    {
      "id": "engineering-fit-20261016",
      "status": "design_proposed",
      "scope": "7 案例的腔体、部件包络、功能基准与装配修订",
      "reference": "docs/engineering/traffic-production-20261016/README.md; engineering_update.source_constraints"
    }
  ],
  "visual_assets": [
    {
      "id": "product-concept-photo",
      "type": "ai_generated_concept_photo",
      "url": "/hardware-structure/photos/smart-ring-photo-v1.jpg",
      "source_status": "ai_generated_concept",
      "revision": "photo-v1",
      "truth_boundary": {
        "zh": "AI 生成的产品概念照片，用于表达外观与使用场景，不是量产实物摄影。",
        "en": "AI-generated product concept image for form and use context; not a photograph of a manufactured unit."
      }
    },
    {
      "id": "structure-thumbnail",
      "type": "structure_preview",
      "url": "/hardware-structure/thumbnails/smart-ring.svg"
    },
    {
      "id": "reference-pack",
      "type": "internal_reference_manifest",
      "url": "/hardware-structure/specs/reference-packs/smart-ring.reference-pack.v1.json"
    }
  ],
  "reference_pack_url": "/hardware-structure/specs/reference-packs/smart-ring.reference-pack.v1.json",
  "reference_policy": {
    "source_media_use": "internal_reference_only",
    "public_output": "original_parameter_model_and_render_only",
    "engineering_authority": "public references do not confirm project dimensions"
  },
  "assumptions": [
    "公开参考包用于校准产品类别语义和装配逻辑：连续钛合金外圈内布置弧形电池、柔性板、贴肤光学窗与充电触点。",
    "任何来自成品图片的不可见尺寸均保持设计建议值或待实物复核，不反向声明为供应商图纸。",
    "公开页面仅展示本站原创参数模型和渲染，不热链或复制参考图片。",
    "本次实际装配几何优先于旧照片投影和原型模板；未执行的环境、强度、寿命及校准测试不因名义空间检查通过而完成。"
  ],
  "engineering_update": {
    "revision": "engineering-fit-r2-20261016",
    "supersedes_revision": "r1-v2-assembly-ref2",
    "status": "design_proposed",
    "production_ready": false,
    "physical_verified": false,
    "geometry_review_status": "pending_physical_validation",
    "source_constraints": [
      {
        "id": "custom-ring-cell",
        "url": "https://www.grepow.com/wearables/smart-ring.html",
        "constraint": "GRP170722 同名有不同电压/容量变体，当前不能从名称推导弧度、胀厚、极耳或允许弯曲半径。",
        "application": "source_constraint_only_proposed_geometry_not_vendor_drawing"
      },
      {
        "id": "ppg-optical-separation",
        "url": "https://www.analog.com/en/resources/technical-articles/guidelines-for-the-optomechanical-integration-of-heartrate-monitors-in-wearable-wrist-devices.html",
        "constraint": "发射与接收需要光学隔离、贴肤光窗与封装后验证；本 40° 开口及隔墙尺寸仅为试验结构。",
        "application": "source_constraint_only_proposed_geometry_not_vendor_drawing"
      }
    ],
    "remaining_gates": [
      "电池的胀厚/极耳/弧形尺寸及充电温区须由实际供应商图纸替换预留包络。",
      "原始 NFC、睡眠特征、PPG、温度及 BLE 范围保留；RF、皮肤接触材料、密封、汗液与算法均未验收。",
      "电芯按 1.7 mm 径向/6.5 mm 轴向候选家族名义尺寸加 0.2/0.4 mm 预留；0.1 mm 名义径向间隙尚未闭合电芯胀厚、壳/FPC 公差和绝缘胶厚，实物验证前不可放行。",
      "矩形环形网格现在使用完整轴向宽度并保留中心孔；电芯和 FPC 为保守安装包络，壳体/粮桶/食盆为名义设计体，实际截面、倒角、公差、底面连接、开孔与密封仍需原生 CAD 和供应商图。"
    ],
    "check_scope": "仅验证所列名义空间、功能位置和装配关系；不代表完整碰撞、强度、密封、电气或量产验收。",
    "proposal_status": "proposed",
    "design_changes": [
      {
        "id": "fit-change-1",
        "title": "分离电池与金属圈",
        "summary": "金属圈内径改为28 mm；保守电芯预留1.9 mm径向×6.9 mm轴向，FPC独立径向层；内衬、电芯、FPC与金属圈不再占同一径向体积。",
        "part_ids": [
          "outer-band",
          "inner-liner",
          "battery",
          "flex-interconnect"
        ]
      },
      {
        "id": "fit-change-2",
        "title": "增加装配入口与功能窗口",
        "summary": "增加可拆端环、非金属RF窗口和PPG遮光隔墙；电芯/胀厚和RF仍待实物验证。",
        "part_ids": [
          "ring-retainer-front",
          "ring-retainer-rear",
          "crown",
          "optical-light-barrier"
        ]
      },
      {
        "id": "fit-change-rectangular-section",
        "title": "环形截面与轴向尺寸一致",
        "summary": "显式采用矩形环形截面和完整轴向宽度，完整环保留中心孔、弧段封闭两端；保守电芯包络不冒充供应商实际外形。",
        "part_ids": [
          "outer-band",
          "inner-liner",
          "battery",
          "flex-interconnect",
          "ring-retainer-front",
          "ring-retainer-rear"
        ]
      }
    ],
    "renderer_update": {
      "previous_revision": "engineering-fit-r1-20261016",
      "section_profile": "rectangular",
      "axial_extent": "centered_full_dimensions_width",
      "scope": "只对显式标记的环形零件生成矩形环形截面；旧案例的 TorusGeometry 保持不变。",
      "authority": "名义结构体或保守安装包络；不是供应商实际截面、圆角、密封或可制造 CAD。"
    }
  },
  "cavities": [
    {
      "id": "crown-board-cavity",
      "owner_part_id": "crown",
      "shape": "box",
      "dimensions": {
        "width": 9.6,
        "height": 2.6,
        "depth": 6.6
      },
      "center": [
        0,
        12.4,
        0
      ],
      "part_ids": [
        "main-pcba"
      ],
      "source_status": "design_proposed",
      "wall_and_service_note": "净空按名义尺寸定义；圆角、紧固件、密封及制造公差需后续 CAD/实物确认。"
    },
    {
      "id": "ring-annular-cavity",
      "owner_part_id": "outer-band",
      "shape": "annular",
      "inner_radius_mm": 11.65,
      "outer_radius_mm": 13.95,
      "width_mm": 7.6,
      "center": [
        0,
        0,
        0
      ],
      "part_ids": [
        "battery",
        "flex-interconnect"
      ],
      "source_status": "design_proposed",
      "assembly_access": "沿 Z 插入裸内胆、电池和 FPC，再装前后端环；灌封前测试。"
    }
  ]
}