Linear actuator

Abstract

A linear actuator is disclosed having a housing and a plurality of components arranged in the housing. The actuator may include at least one conducting component, a group of mechanical, non-conducting components including components of a spindle mechanism, and at least one bearing arrangement designed to support components of the spindle mechanism in the housing. The at least one conducting component may be separated from the group of mechanical, non-conducting components by at least one seal in such a way that two mutually separate spaces sealed off from one another are formed within the housing.

Claims

1. A linear actuator, having a housing and having a plurality of components arranged in the housing, the linear actuator comprising: at least one conducting component; a group of mechanical, non-conducting components, which comprise components of a spindle mechanism; at least one bearing arrangement designed to support components of the spindle mechanism in the housing; the at least one conducting component being separated from the group of mechanical, non-conducting components by at least one seal in such a way that two mutually separate spaces sealed off from one another are formed within the housing; and a continuous housing wall of the housing surrounds the two spaces, wherein a first of the spaces contains the conducting components and is subdivided into two subspaces, and wherein an electric motor is arranged in a first subspace and a sensor-system component is arranged in a second subspace.

2. The actuator as claimed in claim 1, wherein the continuous housing wall is formed by a metal profile and bounding both spaces.

3. The actuator as claimed in claim 1, wherein a ventilation element is arranged in a second of the spaces in which the group of mechanical, non-conducting components, including a component which can be extended out of the space, is situated.

4. The actuator as claimed in claim 3, wherein the ventilation element is selected from the group of ventilation elements which comprises a diaphragm and a double diaphragm valve.

5. The actuator as claimed in claim 3, wherein the ventilation element is integrated into a cover which closes off the housing at an end, wherein it is spaced apart radially from the component which can be extended out of the space.

6. The actuator as claimed in claim 1, wherein only a second of the spaces in which the group of mechanical, non-conducting components is situated has at least one lubricant feed.

7. The actuator as claimed in claim 1, wherein the two subspaces are arranged adjacent to one another, when viewed in a cross section through the housing, and are accessible from one end.

8. The actuator as claimed in claim 1, wherein the two subspaces have different cross sections, when viewed in a cross section through the housing, and are of different lengths, measured in an axial direction of the spindle mechanism.

9. The actuator as claimed in claim 7, wherein the first subspace, in which the electric motor is situated, is arranged as a linear extension of the spindle mechanism, and the second subspace, in which at least one sensor-system component interacting with the spindle mechanism is situated, is arranged parallel to a center line of the spindle mechanism (7), extending over a majority of a length of the housing, wherein a partition wall of the housing delimits the second subspace both with respect to the first subspace and with respect to a second of the spaces in which the group of mechanical, non-conducting components is situated.

10. The actuator as claimed in claim 7, wherein a centering receptacle for a limit switch is arranged in an axially longer sub-space of the first space in which the conducting component is situated.

11. The actuator as claimed in claim 7, wherein a receptacle for a circuit board is arranged in an axially longer subspace of the first space in which the conducting component is situated.

12. A linear actuator, comprising: a column-shaped housing including a housing wall; a conducting component; a group of mechanical, non-conducting components including components of a spindle mechanism; at least one bearing arrangement designed to support components of the spindle mechanism in the housing; the conducting component being separated from the group of mechanical, non-conducting components by at least one seal in such a way that two mutually separate spaces sealed off from one another are formed within the housing, a first space and a second space; and the housing wall surrounding the two spaces, wherein the first space contains the conducting component and is subdivided into two subspaces, and wherein an electric motor is arranged in a first subspace and a sensor-system component is arranged in a second subspace.

13. The actuator as claimed in claim 12, wherein the housing wall is formed by a metal profile and bounding both spaces.

14. The actuator as claimed in claim 12, wherein a ventilation element is arranged in the second space in which the group of mechanical, non-conducting components, including a component which can be extended out of the space, is situated.

15. The actuator as claimed in claim 14, wherein the ventilation element includes a diaphragm or a double diaphragm valve.

16. The actuator as claimed in claim 14, wherein the ventilation element is integrated into a cover which closes off the housing at an end, wherein it is spaced apart radially from the component which can be extended out of the space.

17. The actuator as claimed in claim 12, wherein the two subspaces are arranged adjacent to one another, when viewed in a cross section through the housing, and are accessible from one end.

18. The actuator as claimed in claim 17, wherein a centering receptacle for a limit switch is arranged in an axially longer sub-space of the first space in which the conducting component is situated.

19. The actuator as claimed in claim 17, wherein a receptacle for a circuit board is arranged in an axially longer subspace of the first space in which the conducting component is situated.

20. The actuator as claimed in claim 12, wherein the two subspaces have different cross sections, when viewed in a cross section through the housing, and are of different lengths, measured in an axial direction of the spindle mechanism.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) An illustrative embodiment of the disclosure is explained in greater detail below by means of a drawing, in which:

(2) FIG. 1 shows a linear actuator in section;

(3) FIGS. 2, 3, and 4 show details of the actuator in views according to FIG. 1; and

(4) FIGS. 5 and 6 each show a cross section through the linear actuator.

DETAILED DESCRIPTION

(5) The figures show an electrically operated linear actuator, denoted overall by the reference sign 1, in respect of the basic functioning of which attention is drawn to the prior art cited at the outset.

(6) The actuator 1 has a housing 2 having a continuous housing wall 3, which is formed by a metal profile and extends approximately over the entire length of the actuator 1. Situated within the housing 2 are two mutually separated spaces 4, 5, namely an electrical-system chamber 4, also referred to as the first space, and a mechanical-system chamber 5, also referred to as the second space. Conducting components, including an electric motor 6, are accommodated in the electrical-system chamber 4. A spindle mechanism 7 driven by the electric motor 6 is situated in the mechanical-system chamber 5.

(7) A bearing unit 8, which is sealed off with respect to the housing wall 3 by a static seal 9, is arranged in the housing 2 at the interface between the electrical-system chamber 4 and the mechanical-system chamber 5. The bearing unit 8 is penetrated by a connecting shaft 10, which connects the electric motor 6 to the spindle mechanism 7 and is sealed off with respect to the bearing unit 8 by a dynamic seal 11. The connecting shaft 10 is supported in the bearing unit 8 by means of a rolling bearing, such as a double-row axial ball bearing 12. The dynamic seal 11 is directly adjacent to the double-row axial ball bearing 12, wherein it is arranged on the side of the double-row axial ball bearing 12 facing the electrical-system chamber 4, and therefore the double-row axial ball bearing 12 is situated within the mechanical-system chamber 5. For re-lubrication of the double-row axial ball bearing 12, a lubricant feed 13 in the form of a lubricating nipple is provided. When viewed in the axial direction of the spindle mechanism 7, the lubricant feed 13 is situated between the two rolling element rows of the axial ball bearing 12.

(8) In contrast, there may be no re-lubrication of components within the electrical-system chamber 4. This applies even in cases in which the electric motor 6 drives the connecting shaft 10 and hence the spindle mechanism 7 via a transmission, e.g. a planetary transmission. The spindle mechanism 7 comprises a spindle 14, which is firmly connected to the connecting shaft 10, and a spindle nut 15. A jacket tube 16, also referred to as a tubular connecting rod, which represents a component of the spindle mechanism 7 which can be extended out of the housing 2, is connected to the spindle nut 15.

(9) The electrical-system space 4 is subdivided into two subspaces 17, 18, namely a main electrical-system space 17 and a secondary electrical-system space 18. The main electrical-system space 17, which is also referred to as an upper electrical-system space without restricting generality, has the same cross section as the mechanical-system space 5 andwhen viewed in the axial direction of the spindle mechanism 7is mounted ahead of the mechanical-system space 5. In contrast, the secondary electrical-system space 18, which is also referred to as the lower electrical-system space, is more extensive in the axial direction than the main electrical-system space 7, and therefore there is an overlap between the mechanical-system space 5 and the secondary electrical-system space 18. In other words: there is at least one plane normal to the longitudinal axis of the spindle mechanism 7 which intersects both the mechanical-system space 5 and the secondary electrical-system space 18. In particular, such a plane intersects a limit switch 19, referred to in general terms as a sensor-system component, which is arranged in the secondary electrical-system space 18, is designed as a contactless inductive sensor and interacts with the spindle nut 15 or a part connected firmly to the spindle nut 15.

(10) In the illustrative embodiment shown, the secondary electrical-system space 18 extends over the entire length of the housing 2. In particular, this allows installation of a plurality of sensors constructed in a manner corresponding to the limit switch 19, which detect the position of the spindle nut 15. Associated electric lines are likewise laid in the secondary electrical-system space 18. At the end of the actuator 1 at which the electric motor 6 is situated, the main electrical-system space 17 is connected to the secondary electrical-system space 18 by a cable penetration 21. In the illustrative embodiment, the cable penetration 21 is situated in a partition wall 22 which separates the secondary electrical-system space 18 both from the mechanical-system space 5 and from the main electrical-system space 17. Like the housing wall 3, the partition wall 22 is formed directly from the metal profile from which the housing 2 is produced.

(11) As a departure therefrom, the cable penetration 21 could also be situated in a cover 23 which covers the electrical-system space 4 at the motor end (visible in FIG. 2) of the actuator 1. The cover 23, which may be manufactured from plastic, is sealed off with respect to the metallic housing wall 3 by a seal 24. In addition, by overlapping the housing wall 3, the cover 23 forms a gap seal, which protects seal 24, in particular provides protection for seal 24 from coarse dirt and aging due to UV radiation. A screwed cable gland denoted by 25 is furthermore visible on the cover 23.

(12) The end of the actuator 1 at which the jacket tube 16, also referred to as the tubular connecting rod, projects from the housing 2 is shown in FIG. 4. At this end, the housing 2 is closed by a cover, in this case denoted by 26, wherein the jacket tube 16 is sealed off with respect to cover 26 by two seals 27 arranged in series. Cover 26 closes off both the mechanical-system chamber 5 and the secondary electrical-system space 18. A static flat gasket 28 is inserted between the secondary electrical-system space 18 and cover 26. In a manner similar to the design of cover 23 on the side of the main electrical-system space 7, cover 26 is shaped in such a way that it protects the flat gasket 28 from coarse dirt and UV radiation.

(13) To guide the jacket tube 16, a sliding bearing element 29, which interacts directly with the jacket tube 16, is provided at the end of the housing 2 which is closed with the aid of cover 26 and the dynamic seals 27 and static flat gasket 28. At its end projecting from the housing 2, the jacket tube 16 is closed by a connection element 30, to which a joint eye can be connected, for example.

(14) For re-lubrication of the spindle mechanism 7, a lubricant feed 31 is provided in the region of the sliding bearing element 29, said feed being designed in a manner corresponding to the lubricant feed 13 on the rolling bearing 12 and penetrating the housing 2 and the sliding bearing element 29. As can be seen especially from FIG. 4, the sliding bearing element 29 directly adjoins cover 26.

(15) To admit and release air to and from the mechanical-system chamber 5, an air admission and release device, referred to as ventilation element 32 for short, is integrated into cover 26. The ventilation element 32 is arranged as a linear extension of the secondary electrical-system space 18 and is connected to the mechanical-system chamber 5 via a ventilation duct 33 formed in cover 26. In contrast, the secondary electrical-system space 18 is completely closed on the side of cover 26, unlike on the side of the motor-side cover 23 provided with the screwed cable gland 25, wherein the closure is produced by cover 26.

(16) FIGS. 5 and 6 show two sections through the actuator 1, in each of which the mechanical-system chamber 5 and the secondary electrical-system space 18, situated thereunder, can be seen. Bearing journals, by means of which the actuator 1 as a whole can be supported, are denoted by 20. As can be seen from FIG. 5, the limit switch 19 arranged in the secondary electrical-system space 18 is centered by means of a fastening screw 34 accessible from the outside. The corresponding centering receptacle for the limit switch 19 in the housing 2 is denoted by reference sign 35.

(17) As can be seen from FIG. 6, a further fastening screw 34 is provided within the secondary electrical-system space 18 to fix a circuit board 36 on which various component elements 37, 38 are situated. At the sides, the circuit board 35 engages in guide grooves 39, referred to in general terms as a receptacle, which are formed in the housing wall 3. The housing 2 thus simultaneously performs numerous functions, including the support of the spindle mechanism 7, of the electric motor 6 and of the other, conducting components 19, 37, 38.

LIST OF REFERENCE SIGNS

(18) 1 actuator 2 housing 3 housing wall 4 first space, electrical-system chamber 5 second space, mechanical-system chamber 6 electric motor 7 spindle mechanism 8 bearing unit 9 static seal 10 connecting shaft 11 dynamic seal 12 rolling bearing, double-row axial ball bearing 13 lubricant feed 14 spindle 15 spindle nut 16 jacket tube 17 subspace, main electrical-system space 18 subspace, secondary electrical-system space 19 limit switch 20 bearing journal 21 cable penetration 22 partition wall 23 cover 24 seal 25 screwed cable gland 26 cover 27 seal 28 static flat gasket 29 sliding bearing element 30 connection element 31 lubricant feed 32 ventilation element 33 ventilation duct 34 fastening screw 35 centering receptacle 36 circuit board 37 component element 38 component element 39 guide groove, receptacle