ELECTROMAGNETIC ACTUATOR WITH INTERMEDIATE POSITION

Abstract

An electromagnetic actuating device (10) has an energizable stationary spool element (1) having a stationary core area (2), an anchor unit (3) moveable relative to the spool elements (1) and the core area (2) and has permanent magnet elements (4) and a pestle (5) disposed on one end and having a free end section (5a) for engaging in an actuating partner, the anchor unit (3) being moveable along a longitudinal movement axis (L) in at least two actuating positions (A, B), and the actuator (10) having retaining elements (7) which are spaced apart from the core area, are permanent-magnetically flux-conductive and are formed in such a manner in a third actuating position (C) between the first and second actuating positions (A, B) for interacting with the permanent magnet elements (4) of the anchor unit (3) that the anchor unit is retained in a third actuating position (C) between the first and second actuating positions (A, B) and/or exerts a predefined force potential towards the actuating partner.

Claims

1. An electromagnetic actuator (10) comprising an energizable stationary spool elements (1) having a stationary core area (2) assigned thereto, an anchor unit (3) which is moveable relative to the spool elements (1) and the core area (2) and has permanent magnet elements (4) and a pestle (5), the anchor unit (3) being moveable along a longitudinal movement axis (L) into at least two actuating positions (A, B), and the actuator (10) comprising retaining elements (7) which are spaced apart from the core area, are permanent-magnetically flux-conductive and are formed in such a manner in a third actuating position (C) between the first and second actuating position (A, B) for interacting with the permanent magnet elements (4) of the anchor unit (3) that the anchor unit (3) is retained in the third actuating position (C) between the first and second actuating position (A, B) and/or exerts a predefined force potential towards the actuating partner.

2. The device according to claim 1, the anchor unit (3) being formed in such a manner for interacting with the spool elements (1) and the core area (2) that the anchor unit (3) is moved from the first actuating position (A) to the second or third actuating position (B, C), by choosing a corresponding duration of energization, as a reaction to a selective energization of the spool element (1).

3. The device according to claim 1, the third actuating position (C) being kept stable without energy in an unenergized state of the spool elements (1) via an interaction between the permanent magnet element (4) and the retaining elements (4).

4. The device according to claim 1, the retaining elements (7) being disposed between the first and second actuating position (A, B) and coaxially to the permanent magnet elements (4) along a movement section of the permanent magnet elements (4) along the longitudinal movement axis (L).

5. The device according to claim 1, the retaining elements (7) interacting with the permanent magnet elements (4) in such a manner that a movement of the anchor unit (3) along the longitudinal movement axis (L) from the first retracted actuating position (A) to the second extracted actuating position (B) when nearing or passing through the third actuating position (C) is dampened and/or stopped.

6. The device according to claim 1, the retaining elements (7) for interacting with the permanent magnet elements (4) of the anchor unit (3) being realized in such a manner that the anchor unit (3) exerts an essentially homogeneous force potential toward the actuating partner (11) via a predefined stroke section (H3) between the first and second actuating positions (A, B).

7. The device according to claim 6, the third actuating position (C) being located in the predefined stroke section (H3) and being defined by the engagement of the pestle (5) in a groove bottom (11b) of the actuating partner (11).

8. The device according to claim 6 the exerted force potential ranging from 0.5 N to 5 N.

9. The device according to claim 6, the predefined stroke section (H3) has a hub of 0.5 mm to 2.5 mm.

10. The device according to claim 1, the retaining elements (7) comprising an essentially cylindrical flux-conductive element having a constant inner diameter and outer diameter, which surrounds the permanent magnet elements (4) circumferentially in the third actuating position (C).

11. The device according to claim 1, the retaining elements (7) comprising an essentially cylindrical flux-conductive element having a constant outer diameter and varying inner contour, having an inner diameter becoming reduced in the direction of movement toward the second actuating position (B).

12. The device according to claim 1, the retaining elements (7) having an extension (h1) along the longitudinal movement axis (L) which is essentially the same or greater than the extension of the permanent magnet elements (4) towards the longitudinal movement axis (L).

13. The device according to claim 1, the radial distance (r) between an outer circumference surface of the permanent magnet elements (4) and an inner circumference surface of the retaining elements (7) being between 0.2 mm and 1.4 mm.

14. The device according to claim 1, the retaining elements (7) interacting in such a manner with the permanent magnet elements (4) that a movement of the anchor unit (3) along the longitudinal movement axis (L) from the first retracted actuating position (A) to the third intermediate actuating position (C) is supported and/or accelerated at least partially and along a predefined stroke section (H1) of the anchor unit (3).

15. The device according to claim 1, the device (10) not comprising energy storage means or spring elements between the anchor unit (3) and the core area (2).

16. The device according to claim 1, the device (10) comprising a guide element (6) which is disposed essentially opposite the core area (2), which is made of flux-conductive material and in which the anchor unit is guided by means of the pestle (5).

17. The device according to claim 16, the retaining elements (7) being at a distance to or adjacent to the guide element (6).

18. The device according to claim 1, the first retracted actuating position (A) being kept stable without energy via an interaction between the permanent magnet elements (4) and the core area (2) in the unenergized state of the spool element (1) and/or, the second extracted actuating position (B) being kept stable without energy via an interaction between the permanent magnet element (4) and a guide element (6) of the device (10) in the unenergized state of the spool element (1).

19. The device according to claim 1, the permanent magnet elements (4) having disc-shaped permanent magnets.

20. A system comprising an electromagnetic actuator according to claim 1 and an assigned actuating partner (11), comprising a sliding cam, comprising at least one first guide groove (11a), wherein the first guide groove (11a) is an S-groove, and a guide groove (11b), wherein the guide groove (11b) is an X-groove, which is positioned radially higher on the actuating partner in relation thereto.

21. (canceled)

22. The device according to claim 1, wherein the pestle (5) is disposed on one end of the anchor unit (3) and has a free end section (5a) for engaging in an actuating partner comprising a guide groove (11a, 11b) of a cam shaft (11), and wherein the anchor unit (3) is movable along the longitudinal movement axis (L) into a first retracted actuating position (A) and a second extended actuating position (B).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Further advantages, features and details of the invention are derived from the following description of preferred exemplary embodiments and from the figures.

[0038] FIG. 1a and FIG. 1b each show a schematic longitudinal cut through a preferred embodiment of an electromagnetic actuator according to the present invention in different actuating positions;

[0039] FIG. 2 shows a schematic cut side view of the electromagnetic actuator according to the invention engaged with a guide groove of a cam shaft having different actuating positions;

[0040] FIG. 3 shows a force-path curve according to FIGS. 1 and 2 belonging to the embodiment while the spool elements are unenergized;

[0041] FIG. 4 shows a longitudinal cut through another preferred embodiment of an electromagnetic actuator according to the invention in different actuating positions and engaged with a guide groove of a cam shaft having different actuating positions;

[0042] FIG. 5 shows a force-path curve according to FIG. 4 belonging to the embodiment while the spool elements are unenergized;

[0043] FIG. 6 shows a force-path curve according to FIG. 4 belonging to the embodiment while the spool elements are energized;

[0044] FIG. 7 shows an alternative cross-sectional shape for the retaining elements;

[0045] FIGS. 8a and 8b show a preferred embodiment of the retaining elements as a rolled or bent cylinder;

[0046] FIGS. 9a and 9b show a preferred embodiment of the retaining elements as a rolled or bent cylinder having at least two cutouts on the circumference; and

[0047] FIG. 9c shows a preferred embodiment of the retaining elements alternative to FIGS. 9a, 9b.

[0048] In the figures, the same elements and elements having the same function are referenced with the same numeral.

DETAILED DESCRIPTION

[0049] FIGS. 1a and 1b show a preferred embodiment of electromagnetic actuator 10 according to the invention in a laterally cut view. Electromagnetic actuator 10 comprises a casing 30 having a cylindrical casing section 30a in which further elements of the device, which will be described in the following, are disposed as a component group. Presently, two component groups each are shown beside each other in casing 30 in the corresponding figures in particular for elucidating the actuating position. However, the present invention is not limited thereto; the invention also encompasses embodiments which each have a corresponding number of component groups of the actuator. Accordingly, more than two corresponding component groups can be provided in a shared casing 30.

[0050] Actuator 10 comprises stationary energizable spool elements 1 and a stationary and magnetically conductive core area 2 assigned thereto. Spool elements 1 preferably comprise a spool body 1a and a spool 1b wound around spool body 1a. Actuator 10 further comprises an anchor unit 3 selectively moveable towards spool elements 1 and core area 2 along a longitudinal movement axis L. Anchor unit 3 comprises permanent magnet elements 4 and a pestle 5 having a free end section 5a for engaging in an actuating partner, in particular a guide groove 11a, 11b of an actuating partner 11, e.g., a cam shaft (cf. FIG. 2). Pestle 5 and permanent magnet elements 4 are preferably tightly connected to each other. In this context, permanent magnet elements 4 are preferably disposed on one end of anchor unit 3, and pestle 5 extends to the opposite end. Pestle 5 is guided on an end of casing 30 opposite spool elements 1 in a preferably cylindrical guide element 6, which is realized as a casing section on one end, for example. In particular, the corresponding pestle can be guided in an intended bore 6a of guide element 6. Guide element 6 can be fitted into casing section 30a and is preferably made of magnetically flux-conductive material.

[0051] Core area 2 has a flat inner side 2a and is preferably realized in such a manner for interacting with permanent magnet elements 4 that permanent magnet elements 4 adhere to core area 2 in the unenergized state (cf. FIG. 1a, left component group) and thus a stable first retracted actuating position A of anchor unit 3 can be provided.

[0052] Guide element 6 has a preferably flat inner side 6b, which is realized in such a manner for interacting with permanent magnet elements 4 in an extracted second actuating position B that permanent magnet elements 4 preferably adhere to guide element 6 in the unenergized state (cf. FIG. 1b, left component group) and thus a second actuating position stable without energy can be provided. Pestle 5 and consequently anchor unit 3 can be moved back from second extracted actuating position B to first retracted actuating position A in a generally known manner via a mechanical return or sliding back of the pestle by means of a change in height in a contacted groove guide or the corresponding groove bottom. Alternatively, second actuating position B can be provided by preferably continuously energizing the spool elements and thus by mustering a preferably continuous repelling force on the anchor unit. Pestle 5 can optionally be returned via a returning spring element or by means of its support.

[0053] Between permanent magnet elements 4 and core area 2, generally known antiadhesive means, such as antiadhesive discs or a central elevation 4d, can be provided for maintaining a predefined distance. Permanent magnet elements 4 preferably comprise at least one permanent magnet disk 4a, for example a neodymium-iron-boron magnet, which can be disposed centrally between two magnetically conductive disks 4b, 4c made of iron, for example. Permanent magnet disk 4a and adjoining disks 4b, 4c can be connected to each other by means of a thin adhesive film and/or be surrounded by a ring (not illustrated), preferably made of plastic. This plastic ring can serve to prevent material from chipping off permanent magnet disk 4a. Permanent magnet disk 4a and adjoining disks 4b, 4c can also be connected in a force or form-fitting manner using alternative connective means, e.g., by means of welding, caulking, etc.

[0054] According to the invention, the device comprises permanent-magnetically flux-conductive retaining elements 7. Retaining elements 7 are preferably disposed at a predefined axial distance d to the core area. The distance is between 1 mm to 7 mm, more preferably between 3.5 mm to 6 mm. Retaining elements 7 can be axially distanced to guide element 6, which is disposed opposite the core area, by means of distance d1. Distance d1 is preferably between 1 mm to 7 mm, more preferably between 3.5 mm to 6 mm. In a particularly preferred embodiment, retaining elements 7 are centered, i.e., disposed at half the axial distance between core area 2 and guide element 6.

[0055] A radial distance r between retaining elements 7 and permanent magnet elements 4, in particular a distance between an outer circumference surface of the permanent magnet elements and an inner circumference surface of the retaining elements, is between 0.2 mm and 1.4 mm, more preferably between 0.3 and 0.8 mm.

[0056] An extension or height h1 of retaining elements 7 along longitudinal movement axis L is preferably essentially the same or greater than the extension or height h2 of permanent magnet elements 4 towards longitudinal movement axis L. In an alternative embodiment, retaining elements 7 can also comprise a smaller extension or height h1 than retaining elements 7.

[0057] Retaining elements 7 are realized in such a manner for interacting with permanent magnet elements 4 of anchor unit 3 in a third actuating position C (cf. FIGS. 1a and 1b, right component group) that anchor unit 3 can be retained in third actuating position C between first and second actuating position A, B and/or can exert a predefined force potential towards a contacted actuating partner, as described in the following. In the illustrated embodiment, retaining elements 7 comprise an essentially cylindrical retaining element, which has a preferably homogeneous cross section.

[0058] During operation of actuator 10 for reaching intermediate actuating position C, a relatively short pulse-shaped current is applied to spool elements 1, whereby permanent magnet elements 4 are removed or repelled from core area 2. During a further extracting movement, anchor unit 3 is initially supported or accelerated at least partially by a forming magnetic attractive force between permanent magnet elements 4 and retaining elements 7. This takes place in particular via a predefined stroke section H1 (cf. assigned force-path curve 40 in FIG. 3). In an adjoining stroke section H2, the movement of anchor unit 3 is dampened or decelerated, in particular by radially occurring magnetic transverse forces by means of which anchor unit 3 comes to a standstill at little initial drive by means of the comparatively short pulse-shaped energization and can be retained in intermediate actuating position C by means of the interaction between permanent magnet elements and retaining elements 7. In the illustrated embodiment, anchor unit 3 is retained at a hub of approximately 3.3 mm (compare zero crossing in FIG. 3).

[0059] During operation of actuator 10 for reaching second extracted actuating position B, a comparatively longer pulse-shaped current is applied to spool elements 1 whereby permanent magnet elements 4 and thus anchor unit 3 experience a comparatively larger repelling force and a higher initial drive. This takes place in such a manner that the interaction with retaining elements 7 acting in a damping manner on permanent magnet elements 4 for this operation mode does not lead to anchor unit 3 being retained in third intermediate actuating position C but to anchor unit 3 being brought to extracted actuating position B. When anchor unit 3 nears guide element 6 disposed on one end, the anchor unit experiences an additional magnetic attractive force via the interaction between permanent magnet elements 4 and guide element 6 (cf. stroke section H4 in FIG. 3).

[0060] FIG. 2 shows a preferred embodiment of the system according to the invention consisting of actuator 10 and an assigned actuating partner 11, in particular a cam shaft. Actuator 10 can be inserted in a positioner 20 or be connected thereto as shown. Actuating partner 11 comprises at least one guide groove 11a, for example a known S-groove, and a second guide groove 11b, preferably a known X-groove, which is positioned radially higher on the actuating partner in relation thereto, i.e., at a shorter distance to actuator 10 than first groove 11a.

[0061] Free end section 5a of pestle 5 is contacted with a corresponding groove bottom of groove 11a, 11b. As FIG. 2 shows, the left component group shows second extracted actuating position B of anchor unit 3 and the right component group shows third intermediate actuating position C of anchor unit 3. By means of providing an extracted actuating position B stable without energy and an additional intermediate actuating position C stable without energy as intended by the invention, the actuator can be used for actuating processes having different groove heights and partially overlapping gate tracks of an actuating partner.

[0062] FIG. 4 shows another preferred embodiment of actuator 10 according to the present invention in different actuating positions and engaged with a guide groove of an actuating partner in each instance. In this embodiment, retaining elements 7 have an alternative cross-sectional shape. In particular, retaining elements 7 are formed by an essentially cylindrical flux-conductive element having a constant outer diameter and a varying inner contour. The inner contour has an inner diameter becoming reduced in the movement direction toward second actuating position B. In relation to the circumference, retaining element 7 has a preferably homogeneous cross section in the shape of half a frustum. Retaining element 7 is located on guide element 6 or directly adjoins guide element 6 in this context.

[0063] This embodiment of retaining elements 7 enable an interaction with permanent magnet elements 4 of anchor unit 3 in such a manner that anchor unit 3 exerts a preferably essentially homogeneous force potential towards actuating partner 11 via a predefined stroke section H3 (cf. assigned curve 41 in FIG. 5) between the first and second actuating position. In particular in this embodiment, the retaining elements are realized in such a manner that an axial force acts towards actuating partner 11 or can be exerted on the actuating partner besides a radial magnetic transverse force.

[0064] Third intermediate actuating position C (right component group in FIG. 4) is located in predefined stroke section H3 and can be defined by engaging or resting pestle 5 on a groove bottom of groove 11b, for example. The force potential exerted on actuating partner 11 preferably ranges from 1 N to 5 N, more preferably from 1.5 N to 3 N. Predefined stroke section H3 preferably has a stroke of anchor unit 3 along longitudinal movement axis L of 0.5 mm to 2.5 mm, more preferably of 1 mm to 2 mm.

[0065] FIG. 5 shows a force-path curve 41 for the unenergized state belonging to the embodiment of FIG. 4.

[0066] FIG. 6 shows a force-path curve 42 for the live state belonging to the embodiment of FIG. 4. As FIG. 6 shows, actuator 10 is preferably designed in such a manner that a relatively constant force potential is derived across the stroke in an initial stroke section H5. Preferably the force potential remains in a stroke ranging from 0.5 mm to 2.5 mm within a maximum deviation of 0.5 N to 4 N, more preferably 1 N to 3.5 N. This allows providing a relatively constant force potential when extracting the pestle in particular when wear occurs which leads to a displacement of the curve to the left in FIG. 6 by means of abrasion of the pestle, for example. A substantial deterioration or reduction of the force potential upon wear and consequently a reduction of, for example, the possible shifting times are prevented owing to this. This configuration enables in particular a usage of the actuator for at least 1 million cycles, more preferably 2 million cycles.

[0067] FIG. 7 schematically shows several alternative cross-sectional shapes 8a to 8f for retaining elements 7. Besides cylindrical or annular cross-sectional shape 8 as described above and a cross-sectional shape of half a frustum having an inner diameter 8b becoming reduced in the extracting direction as described above, retaining elements 7 in particular can have other cross-sectional shapes, such as a cross-sectional shape having an inner diameter 8a becoming larger in the extracting direction. Analogously, retaining elements 7 can have a cross-sectional shape 8c, 8d having an essentially triangular notch. Alternatively, retaining elements 7 can have a cross-sectional shape having an essentially rectangular notch 8f. These notches can vary in shape and depth or even extend entirely through retaining elements 7 (cf. 8e).

[0068] FIGS. 8a, 8b show a particularly preferred embodiment of retaining element 7 as a cylindrically bent or rolled sheet-metal part having a preferably consistent wall thickness. Sheet metal 9 is bent to desired cylindrical shape 9 (FIG. 8b) from an initially rectangular sheet 9′ (FIG. 8a). Retaining element 7 created thus can have an opening 9a formed on the circumference due to production and surrounds permanent magnet elements 4 around a circumference of preferably 330°, more preferably at least 350°, most preferably 355°, in the inserted state in device 10.

[0069] FIGS. 9a, 9b show an alternative embodiment of retaining element 7 as a cylindrically bent or rolled sheet-metal part 12 having varying cross-sectional shapes with respect to their circumference. In particular, sheet metal 12 preferably has at least two, preferably several, cutouts 12a or notches preferably of the same kind, which are dispersed around their circumference. These cutouts 12a or notches preferably have an essentially triangular shape in the unrolled state of sheet metal 12′. Through this, oblong bent crowns or protrusions 12c protruding from a cylindrical base body 12b are obtained in the rolled state. Analogously to the embodiment according to FIGS. 8a, 8b, retaining element 7 can have an opening on the circumference or a slit 12d extending axially.

[0070] FIG. 9c shows a design of retaining element 7 alternative to the design of FIGS. 9a, 9b, the cutouts or notches 12a in retaining element 7 having a deviating, in particular trapezoidal shape. Through this, corresponding protrusions 12c are obtained.

[0071] The embodiments described above are merely exemplary, meaning the invention is in no manner limited to the embodiments shown in the figures. In particular, the shown embodiments can be combined with one another.

List of Reference Numerals

[0072] 1 spool element

[0073] 1a spool body

[0074] 1b spool

[0075] 2 core area

[0076] 2a inner side core area

[0077] 3 anchor unit

[0078] 4 permanent magnet elements

[0079] 4a permanent magnet discs

[0080] 4b, c magnetically conductive discs

[0081] 4d elevation

[0082] 5 pestle

[0083] 5a end section pestle

[0084] 6 guide element

[0085] 6a bore guide element

[0086] 6b inner side guide element

[0087] 7 retaining element

[0088] 8 cross-sectional shape

[0089] 8a-8f alternative cross-sectional shapes

[0090] 9 sheet-metal part

[0091] 9a circumferential opening

[0092] 10 actuator

[0093] 11 actuator, cam shaft

[0094] 11a first guide groove, S-groove

[0095] 11b second guide groove, X-groove

[0096] 12 sheet-metal part with cutouts

[0097] 12a cutout/notch

[0098] 12b cylindrical base body

[0099] 12c crown/protrusion

[0100] 12d opening/slit

[0101] 20 positioner

[0102] 30 casing

[0103] 30a cylindrical casing section

[0104] 40 curve of dead embodiment according to FIG. 1-2

[0105] 41 curve of dead embodiment according to FIG. 4

[0106] 42 curve of live embodiment according to FIG. 4

[0107] A first actuating position

[0108] B second actuating position

[0109] C third actuating position

[0110] L longitudinal movement axis

[0111] H1 stroke section supporting extraction movement

[0112] H2 stroke section providing dampening

[0113] H3 stroke section homogeneous force potential

[0114] H4 stroke section attracting to actuating position B

[0115] H5 stroke section homogeneous extraction force

[0116] h1 height of retaining elements

[0117] h2 height of permanent magnet elements

[0118] d axial distance core area to retaining elements

[0119] d1 axial distance retaining elements to guide element

[0120] r radial distance retaining element and permanent magnet