Linear actuator
Linear actuator comprising a housing ( 1 ) consisting of two parts ( 1 a, 1 b ), an electric motor ( 3 ) with a motor shaft, a transmission ( 8 - 11 ) in connection with the motor shaft, a spindle unit in connection with the transmission, where the spindle unit comprises at least a spindle ( 7 ) with a spindle nut ( 14 ) and where the spindle ( 7 ) is equipped with a bearing ( 12 ), an adjustment element ( 13 ) in connection with the spindle unit. The linear actuator is characterized in that a mounting unit ( 2 ) is embedded in the housing, said mounting unit ( 2 ) has a front and a rear end, and where the motor ( 3 ) is placed on the rear end of the mounting unit ( 2 ) and the spindle ( 7 ) is mounted on the front end of the mounting unit ( 2 ), and where the transmission ( 8 - 11 ) is located inside the mounting unit ( 2 ). In addition to being able to reduce the number of components with this construction, e.g. the activation element ( 13 ), the front mounting ( 15 ) and the spindle nut ( 14 ) can be moulded as one single plastic unit, it also allows for a slackening of the tolerances as the assembly of the components is considerably simplified, namely only with regard to the mounting unit ( 2 ). In that connection, the transmission ( 8 - 11 ) is expediently placed in the mounting unit ( 2 ).
1. A linear actuator comprising:
a housing ( 1 ) consisting of two parts ( 1 a , 1 b ),
an electric motor ( 3 ) with a motor shaft,
a transmission ( 8 - 11 ) in connection with the motor shaft,
a spindle unit in connection with the transmission, where the spindle unit comprises at least a spindle ( 7 ) with a spindle nut ( 14 ) and where the spindle ( 7 ) is equipped with a bearing ( 12 ),
an activation element ( 13 ) in connection with the spindle unit, wherein a mounting unit ( 2 ) is embedded in the housing ( 1 ), said mounting unit ( 2 ) has a front end and a rear end, and where the electric motor ( 3 ) is placed on the rear end of the mounting unit ( 2 ) and the spindle ( 7 ) is mounted on the front end of the mounting unit ( 2 ), and where the transmission is located inside the mounting unit; and
wherein the rear end of the activation element ( 13 ) is equipped with a collar ( 16 ), which functions as a stop against the bearing ( 12 ) in the fully retracted position of the activation element ( 13 ).
2. The linear actuator according to claim 1 , wherein the transmission ( 8 - 11 ) is located inside the mounting unit ( 2 ).
3. The linear actuator according to claim 1 , wherein the housing ( 1 ) consists of a front half ( 1 a ) and a rear half ( 1 b ) with a joining surface perpendicular to the longitudinal axis of the actuator.
4. The linear actuator according to claim 1 , the housing ( 1 ) has a recess for form-fitting reception of the mounting unit ( 2 ).
5. The linear actuator according to claim 1 , wherein a recess ( 2 c ) is provided in a side of the mounting unit ( 2 ), said recess fits over a rib in the rear half ( 1 b ) of the housing ( 1 ) for additional fixation of the mounting unit ( 2 ).
6. The linear actuator according to claim 1 , wherein the electric motor ( 3 ) is mounted against the rear end of the mounting unit ( 2 ) for which purpose the mounting unit is equipped with a number of axially protruding pins ( 4 ) fitting into corresponding holes in the front end of the motor.
7. The linear actuator according to claim 1 , wherein the rear end of the rear half ( 1 b ) of the housing ( 1 ) is equipped with a seat ( 5 ) for embedding the rear end ( 3 a ) of the electric motor.
8. The linear actuator according to claim 1 , wherein the transmission comprises a planetary gear ( 6 ) with a sun wheel ( 8 ), driven by the motor ( 3 ) and a ring wheel ( 11 ) mounted on the rear end, the shaft of the spindle ( 7 ).
9. The linear actuator according to claim 1 , wherein the rear end of the spindle ( 7 ) in front of the ring wheel ( 11 ) is equipped with a ball bearing ( 12 ) mounted in a recess ( 2 b ) intended for that purpose in the front side of the mounting unit ( 2 ) in front of the recess ( 2 a ) for the planetary gear ( 6 ).
10. The linear actuator according to claim 1 , wherein at least the rear part of the activation element ( 13 ) which protrudes over the spindle ( 7 ) is tubular and is equipped with internal threads which constitute the spindle nut ( 14 ).
11. The linear actuator according to claim 1 , wherein the activation element ( 13 ) is tubular and that the spindle nut ( 14 ) is constructed in the rear part thereof and that the front mounting ( 15 ) is constructed in the frontmost free end of the activation element ( 13 ).
12. The linear actuator according to claim 1 , wherein the activation element ( 13 ) is secured against rotation in that the collar ( 16 ) is constructed with incisions ( 16 a ) in the circumference which grips around axially running ribs inside the housing ( 1 ) intended for that purpose.
13. The linear actuator according to claim 1 , wherein the activation element ( 13 ) with internal threads (spindle nut 14 )), collar ( 16 ) and front mounting ( 15 ) is moulded in plastic as one single unit.
14. The linear actuator according to claim 1 , wherein a rear mounting ( 18 ) is a fork mounting constructed as an integrated part of the rear half ( 1 b ) of the housing ( 1 ) as the side walls as two flanges ( 18 a , 18 b ) are guided past the end wall in the housing ( 1 ) as the side walls as two flanges ( 18 a , 18 b ) are guided past the end wall in the housing ( 1 ), and in the two elongated side walls there is a transverse hole ( 18 c ) for a pin, bolt, shaft, locking ring or the like for fixation of the rear mounting.
15. The linear actuator according to claim 1 , wherein a bracket ( 19 ) is mounted in a rear mounting ( 18 ) for securing the actuator on a rib, said bracket is triangular with two side walls, upon which there are axle pins ( 4 ) for securing the bracket ( 19 ) in the rear mounting as the two axle pins ( 4 ) are in engagement with a through-going hole ( 18 c ) therein, and that the bracket is provided with a longitudinal groove ( 19 a ) by means of which it can be led over the rib, and that the end of the bracket is equipped with a snap lock ( 19 b ) with a brace-shaped handle for releasing the bracket and thereby the actuator from the mounting rib on the structure in which the actuator is mounted.
16. The linear actuator according to claim 1 , wherein a printed circuit board ( 21 ) for the electric motor is inserted in the housing under the electric motor ( 3 ), and that a cable for the printed circuit board extends through a hole in the rear wall of the housing ( 1 ).