# Bearing housing reference

Read this file when the request is for a bearing housing, bearing seat, bearing
support, pillow block, flanged bearing housing, cartridge bearing holder,
`轴承座`, `轴承支座`, `轴承座壳体`, or `带座轴承` housing.

This reference improves first-pass geometry structure only. It does not certify
bearing fit, tolerance class, coaxiality, lubrication, load capacity, sealing,
casting quality, or manufacturability.

## Object boundary

By default, model the machined housing/seat part that supports a bearing. Do not
model the rolling elements, cage, shaft, bolts, grease nipple, seals, or a full
mounted-bearing assembly unless the user explicitly asks for those as separate
parts.

If the prompt says `bearing`, `bearing seat`, or `轴承座` without more detail,
the semantic core is the support body with a bearing bore and mounting features.

## Recognition

Use this reference when the request includes:

- English: bearing housing, bearing seat, bearing support, pillow block,
  plummer block, flanged bearing housing, cartridge bearing holder.
- Chinese: 轴承座, 轴承支座, 轴承座壳体, 立式轴承座, 法兰轴承座, 带座轴承.
- Adjacent intent: shaft clearance, bearing bore, bearing pocket, mounting feet,
  flange mount, bolt holes, cap, split housing, support ribs, grease port.

## Core invariants

A generated bearing housing should include:

- A bearing bore or bearing pocket sized by a named bearing outer diameter.
- A shaft clearance axis coaxial with the bearing bore.
- Material around the bore thick enough to read as support, not just a thin ring.
- A mounting method: base feet, flange, side lugs, or plate mount.
- Mounting holes with symmetric placement relative to the functional datum.
- A stable datum convention: bearing axis and mounting face are primary.
- Edge relief: practical chamfers/fillets after major cuts.

For a pillow-block style housing, the minimum recognizable structure is:

- Flat base.
- Raised bearing boss or arched support.
- Horizontal bearing bore through the support.
- Two base mounting holes.
- Optional ribs connecting boss to base.

## Default strategy

When under-specified, generate a simple pillow-block bearing housing:

- Bearing axis along X.
- Flat rectangular base on the XY plane.
- Bearing center above the base by `bearing_center_height`.
- Cylindrical or rounded boss around the bearing bore.
- Coaxial through bore for shaft clearance plus a larger bearing seat/pocket.
- Two elongated or round mounting holes in the base, symmetric about the Y axis.
- Two ribs from base to bearing boss if there is enough room.
- Fillets/chamfers last.

Do not default to a full assembly. Do not default to visible bearing balls. Do
not default to a random bracket with holes but no bearing bore.

## Common variants

### Pillow block / plummer block

- Base-mounted housing with horizontal bearing axis.
- Two or four mounting holes in the base.
- Raised central boss, arch, or saddle around the bore.
- Optional split cap only if the user asks for split housing or cap bolts.

### Flanged bearing housing

- Circular, square, oval, or diamond flange around the bearing bore.
- Bearing axis usually normal to the flange face.
- Bolt holes arranged on a bolt circle or symmetric flange pattern.
- Optional pilot lip or locating register on the mounting face.

### Plate-mounted bearing seat

- Flat or block-like plate with bearing pocket.
- Bearing axis may be normal to the plate.
- Mounting holes belong to the plate datum, not random locations.

### Split bearing housing

- Lower base and upper cap are separate parts or clearly separated bodies.
- Cap bolts and split plane must be represented if split form is requested.
- If source-level assembly is not needed, a simplified monolithic split-line
  groove is acceptable, but label the assumption.

### Cartridge bearing holder

- Cylindrical sleeve-like body with flange or clamp features.
- Bearing pocket and shaft clearance are coaxial.
- Include retaining shoulder or snap-ring groove when requested.

## Required parameter roles

Use semantic parameters before modeling:

- `bearing_outer_diameter`
- `bearing_width`
- `shaft_diameter`
- `shaft_clearance_diameter`
- `bearing_bore_diameter`
- `bearing_bore_depth`
- `bearing_center_height`
- `wall_thickness`
- `base_length`
- `base_width`
- `base_thickness`
- `mount_hole_diameter`
- `mount_hole_spacing_x`
- `mount_hole_spacing_y`
- `boss_outer_diameter`
- `boss_width`
- `flange_outer_diameter`
- `flange_thickness`
- `bolt_count`
- `bolt_circle_diameter`
- `rib_thickness`
- `fillet_radius`

Only define optional parameters used by the selected variant.

## Feature roles to plan explicitly

Use these roles in the CAD brief and source structure:

- `mounting_base`
- `bearing_boss`
- `bearing_seat_bore`
- `shaft_clearance_bore`
- `mounting_holes`
- `flange_mount`
- `pilot_lip`
- `support_ribs`
- `split_cap`
- `cap_bolts`
- `retaining_groove`
- `grease_port`
- `datum_mounting_face`
- `datum_bearing_axis`

## Construction sequence

1. Select the variant from the prompt. If no variant is specified, use pillow
   block.
2. Define the datum system:
   - pillow block: base bottom face is Z=0; bearing axis is X.
   - flanged housing: flange mounting face is the primary plane; bore axis is
     normal to it.
3. Build the base, flange, or plate body first.
4. Add the bearing boss/support body and ensure it intersects the base/flange.
5. Cut the shaft clearance bore and bearing seat coaxially.
6. Cut mounting holes using symmetric positions or bolt circle pattern.
7. Add ribs only when they intersect both base/flange and boss.
8. Add optional split line, cap features, grease port, retaining groove, or pilot
   lip if requested.
9. Apply chamfers and fillets last.

For through bores and mounting holes, overshoot cutting tools through the target
faces. Avoid coplanar cutting tools.

## Common failures to prevent

- A generic bracket with no bearing bore.
- A ring with no mounting method.
- Bearing bore and shaft clearance not coaxial.
- Missing bearing center height in pillow-block form.
- Mounting holes asymmetric when the variant implies symmetry.
- Ribs that float or only touch at an edge.
- Base thinner than mounting-hole diameter without reason.
- Side openings or decorative slots with no bearing-seat purpose.
- Generating balls, cages, shafts, fasteners, or seals when the user asked only
  for the housing.
- Confusing bearing housing with shaft, flange, or motor mount.

## Validation targets

After generation, inspect or reason about:

- Bearing bore diameter/depth and shaft clearance diameter.
- Coaxiality of bearing bore and shaft clearance.
- Bearing center height above mounting face for pillow-block form.
- Base or flange dimensions and thickness.
- Mounting-hole count, size, and symmetry or bolt-circle diameter.
- Boss wall thickness around bearing seat.
- Rib attachment to both base/flange and boss when ribs exist.
- Single connected solid unless the user requested an assembly or split housing.