Electromechanical actuator having design elements for improved oil guidance
A linear actuator includes a hermetically sealed housing, a cantilever that can be retracted into and extended out of the housing, and several components provided in the linear actuator. The components are configured so as to facilitate a flow of lubricating oil through the linear actuator, in particular when the cantilever is rapidly retracted and extended. This is achieved in that through-holes are provided in some components, through which lubricating oil and gas that has been filled into the housing can flow upon retraction and extension.
1 . A linear actuator, comprising:
a housing;
a cantilever, wherein the cantilever is borne along a longitudinal axis in a linearly movable manner in a first cavity of the housing and projects out of the housing, and wherein the cantilever comprises a second cavity and a threaded nut that engages in a screw-like manner with a threaded spindle, and wherein the threaded nut is configured to be borne in a torque-proof manner in the housing;
a spindle pivot bearing in which the threaded spindle is borne in the housing at an end facing away from the cantilever; and
a motor configured to rotate the threaded spindle,
wherein the housing and the cantilever are configured to define a space that is hermetically sealed against the external atmosphere by way of seals and is filled with a fluid,
wherein the fluid comprises compressible and incompressible constituents, and
wherein two components are disposed in the space sealed against the external atmosphere, each component including at least one through-hole, respectively, which is open to the interior of the space for circulation of fluid therethrough upon a change of state of the linear actuator,
wherein one of said two components is positioned between said threaded nut and said second cavity, and the other of said two components is positioned between said threaded nut and said end facing away from the cantilever.
2 . The linear actuator according to claim 1 , wherein said other of said two components comprises a shaft sealing ring.
3 . The linear actuator according to claim 1 , wherein said one of said two components comprises an additional pivot bearing for supporting the cantilever.
4 . The linear actuator according to claim 1 , wherein a through-hole is provided in the threaded spindle.
5 . The linear actuator according to claim 1 , further comprising a piston which is received at one end of the threaded spindle in a rotatable manner about the longitudinal axis via a piston pivot bearing.
6 . The linear actuator according to claim 5 , wherein a through-hole is provided in the piston.
7 . The linear actuator according to claim 5 , wherein the piston is configured in the form of a pot.
8 . The linear actuator according to claim 1 , further comprising an adapter part provided on the threaded nut, the adapter part including an internal thread, an external thread, a first collar projecting radially inward, and a second collar projecting radially outward, wherein the cantilever is screwed into the internal thread and tensioned against the first collar, and the threaded nut is screwed onto the external thread and tensioned against the second collar.
9 . The linear actuator according to claim 1 , wherein the fluid in the hermetically sealed space of the linear actuator comprises a liquid portion and a gaseous portion, wherein the amounts of the liquid portion and the gaseous portion are determined such that, in a maximally retracted state of the linear actuator, an internal pressure in the linear actuator does not substantially exceed a value of 2 MPa and the internal pressure in a maximally extended state does not substantially fall below a value of 0.8 MPa.
10 . The linear actuator according to claim 1 , wherein the threaded spindle comprises a spindle sealing surface on its external circumferential surface that has a constant radius in relation to the longitudinal axis, wherein the spindle sealing surface defines at least one first opening that is arranged respectively in the direction of the longitudinal axis between the spindle sealing surface and the spindle pivot bearing, wherein the spindle sealing surface is in sealing contact with a separate sealing ring, and wherein the sealing ring is fastened onto the housing in such a way that it seals the first cavity.
11 . The linear actuator according to claim 1 , wherein the motor is an electric motor.
12 . A linear actuator, comprising:
a housing;
a cantilever, wherein the cantilever is borne along a longitudinal axis in a linearly movable manner in a first cavity of the housing and projects out of the housing, and wherein the cantilever comprises a second cavity and a threaded nut that engages in a screw-like manner with a threaded spindle, and wherein the threaded nut is configured to be borne in a torque-proof manner in the housing;
a spindle pivot bearing in which the threaded spindle is borne in the housing at an end facing away from the cantilever; and
a motor configured to rotate the threaded spindle,
wherein the housing and the cantilever are configured to define a space that is hermetically sealed against the external atmosphere by way of seals and is filled with a fluid,
wherein the fluid comprises compressible and incompressible constituents, and
wherein one or more components are disposed in the space sealed against the external atmosphere, each including at least one through-hole, respectively, which is open to the interior of the space for circulation of fluid therethrough upon a change of state of the linear actuator,
wherein said one or more components includes the threaded nut, in which the at least one through-hole includes at least one through-hole that extends parallel to the longitudinal axis of the linear actuator.