Regex in xs:element xsd

i try to put a regex in xs:element name in a xsd file for validate multiple file xml.

</xs:schema>
    <xs:element name="DIPR_C4001_01">
        <xs:complexType>
            <xs:sequence>
                <xs:element name="scheda" minOccurs="1" maxOccurs="unbounded"/>
            </xs:sequence>
        </xs:complexType>
    </xs:element>
</xs:schema>

The element name is always different but with the same format XXXX_XXXXX_XX so I created this regex (\ w {4} _ \ w {2} \ d {3} _ \ d {2}), but if I put this string in the name of the item, I get an error. Could you please let help me solve this problem?