How much of the 90 s swap can an AGV battery case influence?

A: 12 s. Drive-in, lift, lock confirmation and departure belong to the vehicle; the case only has to land the blind mate first time.

Why not use two round pins?

A: Two round pins over-constrain. Spacing carries ±1.2 mm on each side and a distorted shell will not go in. A diamond pin constrains one direction only.

Where does the ±2 mm blind-mate tolerance come from?

A: A ±10 mm stop repeat, cut by a 15° cone and a 12 mm lead-in with 4 mm of capture, leaving ±1 mm at the mouth.

Does a 0.3 mm gap really mean replacement?

A: Yes. At 0.3 mm the rock is 0.4 mm, still inside the window; at 0.45 mm it is 0.6 mm and a failed insertion turns 90 s into 106 s.

Can the two lock pins be reduced to one?

A: Not advised. A single pin leaves no second constraint, and a 200 A connector pushes the case out by more than 3 mm.

AGV Battery Case

Quick answer: An AGV battery case is judged on a 12 s blind-mate window at ±2 mm, a 0.3 mm wear limit after 5000 swaps, and 120 N of insertion force.

Where the 90 Seconds Actually Goes
Two Pins, One Round and One Diamond
Two Locks: Load and Anti-Drop
The 0.3 mm Gap After 5000 Cycles
Seating Face and a 31 kg Pack
FAQ

1. Where the 90 Seconds Actually Goes

A 90 s battery swap is five movements. The vehicle drives in for 30 s, lifts and aligns for 15 s, blind-mates for 12 s, confirms the lock for 8 s and leaves for 25 s. Only the 12 s belongs to the case.

That narrows the brief: a retry sends the vehicle back through lift and alignment, the cycle becomes 106 s, and a line of 8 vehicles loses 3 swaps an hour.

Two numbers carry the alignment: the error the vehicle repeats and the capture the cone provides. It stops within ±10 mm; the case swallows that inside ±2 mm, and only the cone is allowed to steer.

2. Two Pins, One Round and One Diamond

The pair is one round pin and one diamond pin, 320 mm apart. Two round pins over-constrain: a shell slightly out of square will not go in. The diamond pin is relieved 2.5 mm on both flats and absorbs ±1.2 mm of spacing error.

AGV battery case moulding bench with open black shells, a metal rod inside one, tape roll beside, worker passing the blue machine

The pin nose is a 15° cone with a 12 mm lead-in and 4 mm of radial capture. Arriving ±10 mm off, the cone pushes the case back toward centre, so the error at the hole mouth is inside ±1 mm.

Pin diameter tier	Cone angle	Lead-in	Radial capture	Side load per pin	Pack weight served
φ10 mm	15°	10 mm	3.2 mm	4.5 kN	up to 25 kg
φ12 mm	15°	12 mm	4.0 mm	6.5 kN	25–40 kg
φ16 mm	12°	15 mm	5.2 mm	11 kN	40–70 kg

Hardness is HRC 50 with a 0.3 mm case depth: softer pins round over after 5000 insertions, harder ones shear against a mis-set pallet. The holder sits on 0.5 mm of clearance with three M8 bolts at 22 N·m.

3. Two Locks: Load and Anti-Drop

The main pin is φ16 mm through the side of the case, taking the reaction of a 200 A connector and the longitudinal load of an emergency stop. The secondary pin is φ10 mm, 60 mm above it, and does one job: it stops the case backing out if the main pin has not seated.

Both run on 80 N springs with an 8 mm release stroke, manual release staying under 60 N; above that, maintenance reaches for a pry bar and clearance jumps from 0.05 mm to 0.2 mm. Contact length is 12 mm: under 8 mm the bore goes oval, over 16 mm the case gains 1.4 kg of wall.

Lock arrangement	Pin size	Contact length	Load direction	Release stroke	False-lock risk
Single pin	φ16 mm	12 mm	horizontal	8 mm	high
Main plus secondary	φ16 + φ10 mm	12 mm	horizontal and vertical	8 mm	low
Twin main pins	φ16 × 2 mm	14 mm	horizontal	10 mm	medium

Seating is confirmed mechanically: a 22 mm window shows red until both pins pass dead centre, green after, and the 8 s confirmation step reads only that window.

4. The 0.3 mm Gap After 5000 Cycles

A new case runs an H7/g6 fit at 0.02 mm to 0.06 mm. That is oil film, not slack: below 0.02 mm the pin squeezes grease out of the bore and insertion force climbs from 90 N to 130 N, past the 120 N ceiling.

AGV battery case workshop row of moulding machines, a worker bending between them, floor fan in front, cartons on a pallet

The bore carries a tin-bronze bushing, 2 mm wall, reamed after pressing. It moves wear off the moulded shell, which cannot be reworked once the bore opens, onto a part costing 6% of the case and pressed out in 25 min.

Cycle tier	Measured gap	Insertion force	Action
0	0.02–0.06 mm	90 N	in service
1000	0.08 mm	96 N	regrease
3000	0.18 mm	104 N	regrease, check pin nose
5000	0.30 mm	112 N	change bushing
8000	0.45 mm	124 N	stop, change pin and bushing

The 0.3 mm limit comes from the blind-mate window. At 0.3 mm the case rocks about 0.4 mm on the pin, and with ±10 mm of stop error the cone still pulls the result inside ±2 mm. At 0.45 mm it is 0.6 mm and one insertion in fifty fails. Grease goes in every 1000 cycles, 2 g at a time.

5. Seating Face and a 31 kg Pack

A 48 V/60 Ah pack weighs 31 kg and lands on four ribs 5 mm high, flat within 0.5 mm. Beyond that the pack floor touches on two points, takes a 0.3 mm set after 5000 swaps, and connector alignment drifts with it.

Pack tier	Pack weight	Seating ribs	Clamp torque	Case weight	Loaded weight
48 V/40 Ah	22 kg	4	20 N·m	5.9 kg	28 kg
48 V/60 Ah	31 kg	4	25 N·m	6.8 kg	38 kg
48 V/80 Ah	42 kg	6	28 N·m	7.6 kg	50 kg

Four clamps at M8 and 25 N·m hold it down: below 18 N·m the pack shifts 1.5 mm in an emergency stop, above 30 N·m the rib roots whiten. The connector floats ±1.5 mm at under 120 N, a separate tolerance from the ±2 mm pin window.

The shell is 620 × 420 × 260 mm with 5 mm walls and a 6 mm base. At 38 kg loaded it is past one-person handling, so each side gets a 90 × 35 mm fork pocket, 45 mm above the base.

Conclusion

An AGV battery case is held to four numbers: a ±2 mm blind-mate window, a 0.3 mm wear limit, 120 N of insertion force and a 90 s cycle. A φ12 mm round pin with a diamond partner pulls ±10 mm of stop error into the cone; a φ16 mm main pin and a φ10 mm secondary catch the connector reaction; a 2 mm bronze bushing keeps wear on a part costing 6% of the case.