A motion conversion apparatus (110) comprises a rodrack assembly (110) and a gearshaft member (150). The rodrack assembly (110) comprises a first gear connection member (120) and two guide members (140). The gearshaft member (150) comprises a second gear connection member (160) configured to engage with the first gear connection member (120), and a guiding surface arrangement (170) configured to contact the guide members (140). The rodrack assembly (110) is configured to provide rotation of the gearshaft member (150) about a rotational axis (A) by reciprocating linear motion of the rodrack assembly (110) along a first spatial dimension (D1) orthogonal to the rotational axis (A), and/or the gearshaft member (150) is configured to provide reciprocating linear motion of the rodrack assembly (110) along the first spatial dimension (D1) by rotational motion of the gearshaft member (150) about the rotational axis (A). The guiding surface arrangement (170) is configured to simultaneously contact each guide member (140) during at least a portion of the reciprocating linear motion of the rodrack assembly (110).