本案是一起由于用人单位违法不与劳动者签订书面劳动合同而引发的劳动争议纠纷。在本案中,原被告双方对于未签订劳动合同的事实并无异议,双方争议的焦点是关于劳动者主张未与用人单位签订书面劳动合同支付二倍工资的请求是否已过仲裁时效,即本案所涉及的仲裁时效应从劳动者知道或应当知道 This case is a labor dispute arising due to the employer violating the law without signing a written labor contract with the employee. In this case, the original defendants did not dispute the fact that they did not sign the labor contract. The dispute between both parties focused on whether the worker's claim that the employer failed to sign a written labor contract with the employer has passed the arbitration time limit, that is, The arbitration time involved should be known or should be known to the worker