Oracle 18c

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8 rows affected

WITH split_bins (id, name, quantity, maxquantity, tag, effective_quantity, prev_quantity) AS (
  SELECT id,
         name,
         quantity,
         maxquantity,
         FLOOR(
           COALESCE(
             SUM(quantity) OVER (
               PARTITION BY name
               ORDER BY id
               ROWS BETWEEN UNBOUNDED PRECEDING AND 1 PRECEDING
             ),
             0
           )
           / maxquantity
         ) + 1,
         LEAST(
           maxquantity
           - MOD(
               COALESCE(
                 SUM(quantity) OVER (
                   PARTITION BY name
                   ORDER BY id
                   ROWS BETWEEN UNBOUNDED PRECEDING AND 1 PRECEDING
                 ),
                 0
               ),
               maxquantity
             ),
           quantity
         ),
         0
  FROM   articles
UNION ALL
  SELECT id,
         name,
         quantity,
         maxquantity,
         tag + 1,
         LEAST(
           quantity - prev_quantity - effective_quantity,
           maxquantity
         ),
         prev_quantity + effective_quantity
  FROM   split_bins
  WHERE  prev_quantity + effective_quantity < quantity
)
SEARCH DEPTH FIRST BY id SET id_order
SELECT id,
       name,
       quantity,
       maxquantity,
       name || '_part' || tag AS tag,
       effective_quantity
FROM   split_bins;

ID	NAME	QUANTITY	MAXQUANTITY	TAG	EFFECTIVE_QUANTITY
1	name_a	3	5	name_a_part1	3
2	name_a	1	5	name_a_part1	1
3	name_a	3	5	name_a_part1	1
3	name_a	3	5	name_a_part2	2
4	name_a	5	5	name_a_part2	3
4	name_a	5	5	name_a_part3	2
5	name_b	7	4	name_b_part1	4
5	name_b	7	4	name_b_part2	3
6	name_b	2	4	name_b_part2	1
6	name_b	2	4	name_b_part3	1
7	name_c	6	2	name_c_part1	2
7	name_c	6	2	name_c_part2	2
7	name_c	6	2	name_c_part3	2
8	name_c	2	2	name_c_part4	2