EP3257061B1 - Central actuator system for an oscillating motor adjuster of a camshaft - Google Patents

Description

Technical area

The invention relates to a central actuator, in particular for a solenoid valve of a swivel motor camshaft adjuster of an internal combustion engine of a motor vehicle.

State of the art

From the DE 10 2005 049 663 A1 an electromagnet with a cylindrical hollow magnet body is known, which has a yoke, a pole core with a characteristic-influencing armature counterpart and a housing, as well as a cylindrical coil and a cylindrical armature with guide rod and armature piston, which is arranged displaceably to the pole.

In the electromagnet, the armature piston is axially displaceably mounted in a bearing tube or a bearing sleeve, with the bearing tube or bearing sleeve ending at one end within the pole core or within the armature counterpart of the pole core and at another end over the yoke, in particular up to the yoke there Transverse wall of the housing is sufficient, as well as having the sleeve base at this end in the case of the design as a bearing sleeve. The pole core or its armature counterpart, which is penetrated by the guide rod, closes the housing.

From the US 2004/0257185 A1 a variable-force electromagnet is known, the armature space of which is closed off by means of a pole piece and a facing disc. A bearing bush for mounting a plunger is arranged in a central bore of the pole piece. A housing connects the facing disc and the pole piece to a flow tube assembly.

The US 2004/0041114 A1 and the DE 101 96 576 B4 a solenoid valve with an electromagnet can be seen in each case, the armature of which has a plunger which is provided so as to be axially displaceable in a socket. This bearing bush is arranged in a magnetic yoke which is fastened in a fastening flange. A magnet housing encloses the electromagnet and is arranged attached to a valve socket.

Furthermore, on DE 10 2010 014140 A1 referenced, which discloses an electromagnetic actuating device with an electromagnetic assembly with an external magnetic circuit and a guide and bearing area arranged at least in areas within a coil for receiving an armature system, at least one magnetic circuit part having an opening in which the armature system is at least temporarily arranged, wherein the magnetic circuit part provided with an opening is connected to a sealing element which is injection-molded onto the magnetic circuit part provided with the opening.

Disclosure of the invention

One object of the invention is to create a central actuator that is inexpensive to manufacture and easy to assemble, in particular for a solenoid valve of a swivel motor camshaft adjuster.

The aforementioned object is achieved according to one aspect of the invention with the features of the independent claim.

Favorable configurations and advantages of the invention emerge from the further claims, the description and the drawing.

A central actuator is proposed, in particular for a solenoid valve of a swivel motor camshaft adjuster, which comprises a housing which encloses the central actuator. The central actuator further comprises a pole tube and a pole core, which are arranged within at least one coil generating a magnetic field, and an actuating plunger which is arranged on an armature, which is designed to be axially displaceable in an armature space.

A closing element is provided for closing the armature space, which comprises at least one pole core insert with a central bore and a bearing bush arranged in the central bore of the pole core insert, the actuating tappet being mounted axially displaceably in the bearing bush. According to the invention the closing element further comprises a closing cover and is provided as a preassembled unit.

The preassembled unit allows simple assembly with simultaneous axial fixation of the pole core insert.

The actuating tappet is also securely guided in the bearing bushing, so that guidance of the armature on which the actuating tappet is arranged is also ensured.

The end cover has a central bore in which the bearing bush is arranged, so that the unit can be easily positioned.

In addition, according to the invention, the bearing bush is produced using a plastic injection molding process and the cover and the pole core insert are provided as inserts, which are provided with the material of the bearing bush overmoulded in the area of their central bores. The plastic injection molding process represents a simple and very inexpensive manufacturing process, which makes it possible to manufacture the closing element simply and inexpensively.

According to an advantageous embodiment of the invention, the bearing bush has recesses arranged in the axial direction for equalizing pressure between the armature space and the outer space of the central actuator.

The pressure equalization ensures a volume equalization of the enclosed hydraulic fluid or the enclosed air between the armature space and an outer space of the central actuator. Such a pressure equalization is important both in dry operation, that is to say when the armature space is filled with air, and also in the case of operation with hydraulic fluid in the armature space. Even if hydraulic fluid has to be kept out of the area outside the pole tube, this hydraulic fluid inside the pole tube is of great advantage because it can create a pressure equalization on both sides of the armature. Likewise is the The lubricating effect of the hydraulic fluid is advantageous, so that a reduction in friction and wear is achieved as a result.

For this purpose, in a particularly advantageous embodiment, there are recesses in the bearing bushing, which guide the hydraulic fluid from the hydraulic part of a solenoid valve to the electromagnetic part of the solenoid valve, i.e. the central actuator, in such a way that the same hydraulic pressure is applied to the closing element on both sides. However, it is also conceivable to arrange the recesses in the pole core insert and in the end cover.

On its side facing the armature, the bearing bush preferably has a collar as a stop for the armature during its axial movement. Such a fixed stop keeps the end face of the armature at a certain distance from the disc-shaped pole core insert and thus prevents the armature from sticking to the end face of the armature on the pole core insert. Gluing would change the movement behavior of the anchor and that would be necessary for the operation of the anchor Significantly influence magnetic forces, so that the entire dynamic behavior of the central actuator would be changed. Therefore, such a collar as an anti-adhesive disk can positively influence the dynamic behavior as well as the energy consumption of a central actuator that is operated with magnetic forces.

The actuating tappet can advantageously be pressed into a central bore in the armature. Armature and actuating plunger are usually made of different materials. The armature is preferably made of soft iron, while the actuating tappet is made of non-ferrous metal, for example, in order to also have the necessary material properties such as hardness for operating a solenoid valve. The armature, however, must essentially have the correct magnetic properties to operate in the coil's magnetic circuit. Therefore, the armature can for example be provided with a bore into which the actuating tappet can be inserted, whereby it can preferably be pressed in, which produces an inexpensive and permanent connection between the armature and the actuating tappet.

According to an advantageous embodiment of the invention, the actuating plunger can have one or more transverse bores for pressure equalization between a front and a rear side of the armature between the armature and the bearing bush, which open into a central longitudinal bore leading into the bore of the armature.

Another advantageous embodiment of the invention, however, provides that the actuating plunger has flats which extend on both sides beyond a press-fit area of the bore, and the bore is stepped and has an enlarged inside diameter beginning in the area of the flats. The flattened areas and the enlarged inner diameter can be produced simply and inexpensively, so that the volume and pressure equalization can be ensured in a simple and inexpensive manner.

Alternatively, the actuating plunger and the armature can be provided in one piece, which means that the absence of the bore for receiving the plunger results in a high

Magnetic force results in a compact design. Furthermore, this can improve the coaxiality of the two components.

In this embodiment, the anchor can be manufactured inexpensively from a free-cutting steel.

According to an advantageous embodiment of the invention, the armature can be designed to be displaceable in a non-magnetic sleeve in the axial direction pointing towards the pole core insert.

If this sleeve has a continuous inside diameter over the entire working area over which the armature travels, the armature can be guided over its entire length and it is ensured that the armature cannot tilt, which would otherwise lead to high magnetic radial forces on the armature and thus would lead to high friction with respect to the pole tube.

If the pole tube and the pole core are made in one piece and the armature is designed to be displaceable in the axial direction pointing towards the pole core insert, then, according to an alternative embodiment, guidance of the armature can also be ensured.

At an end facing the closing element, the armature preferably has a diameter shoulder as a guide surface for guidance in the armature space. With the mounting of the actuating plunger in the bearing bushing as a second bearing point, this two-point mounting with a large bearing spacing allows the armature to be guided well, since small coaxial errors from an outer diameter of the pole core insert to an inner diameter of the bearing bushing as well as an armature outer diameter and a plunger outer diameter can be compensated for.

According to one exemplary embodiment, the guide surface of the armature can be of polygonal design and have circumferentially uniformly distributed flat areas for pressure compensation between a front and a rear side of the armature.

A particularly inexpensive alternative embodiment provides that

Provide guide surface of the armature as a cylindrical diameter shoulder with an enlarged outer diameter.

The housing can advantageously be manufactured using a plastic injection molding process. In this way, it is possible in a cost-effective manner to manufacture the housing of the central actuator from injection-molded plastic, provided that the various components of the pole yoke that ensure the closed magnetic flux are inserted during the injection-molding process. The closure of the housing from an outer space of the central actuator forms the end cover, which is preferably provided fastened to the housing by means of ultrasonic rivets.

Brief description of the drawings

Further advantages emerge from the following description of the drawings. Exemplary embodiments of the invention are shown in the drawings. The drawings, the description and the claims contain numerous features in combination. The person skilled in the art will expediently also consider the features individually and combine them into meaningful further combinations.

It shows by way of example:

Fig. 1

a section through a central actuator according to a first embodiment of the invention;

Fig. 2

a section through the closing element of the central actuator according to Fig. 1 ;

Fig. 3

a section through a central actuator according to a second embodiment of the invention;

Fig. 4

an anchor of the second embodiment according to Fig. 3 ;

Fig. 5

a section through a central actuator according to a third embodiment of the invention and

Fig. 6

an enlarged view of the armature with pressed-in actuating plunger of the third embodiment according to FIG Fig. 5 .

Embodiments of the invention

In the figures, the same or similar components are numbered with the same reference symbols. The figures show only examples and are not to be understood as restrictive.

Fig. 1 shows a section through a central actuator 10 according to a first embodiment of the invention. The central actuator 10, which is particularly suitable for a solenoid valve of a swivel motor camshaft adjuster, comprises a pole tube 12 which is arranged within a cylindrical coil 52 which generates a magnetic field, and a housing 46 which encloses the central actuator 10. The housing 46 is manufactured using a plastic injection molding process, so that it is possible in a cost-effective manner to manufacture the housing 46 and at the same time insert various components of a pole yoke 50 during the injection molding process, which ensure the closed magnetic flux.

The central actuator 10 further comprises an in Fig. 2 Closing element 18, shown enlarged, which closes the housing 46, wherein the closing element 18 comprises a pole core insert 22 with a central bore 24 and a bearing bush 26 arranged in the central bore 24 of the pole core insert 22. It also includes a cover 42 and is provided as a preassembled unit.

The end cover 42 is provided fastened to the housing 46 by means of ultrasonic rivets, for example. For this purpose, the housing 46 has an ultrasonic geometry in the form of several projections 62 which protrude through bores 64 of the cover 42. The protrusions 62 are melt-deformed by the ultrasonic riveting so that the end cap 42 is securely attached to the housing 46.

Like in particular from Fig. 2 As can be seen, the end cover 42 also has a central bore 43 in which the bearing bush 26 is arranged.

The bearing bush 26 is expediently manufactured using a plastic injection molding process and the end cover 42 and the pole core insert 22 are provided as inserts, which are inserted into the injection molding tool when the bearing bush 26 is manufactured and the material of the bearing bush is overmolded in the area of their central bores 24, 43 . As a result, the bearing bush 26 is permanently sealed against the pole core insert 22 and the end cover 42.

An actuating tappet 20 is arranged on an armature 28, which is designed to be displaceable within an armature space 60 in an axial direction L pointing towards the pole core insert 22, and is mounted axially displaceably in the bearing bush 26, while the armature 28 is mounted in a non-magnetic sleeve 29 . This is mounted in the pole tube 12 and a pole core 14. As can be seen, the sleeve 29 extends to an end of an armature space 60 closed by the cover 42 and has an internal diameter extending over the entire working area over which the armature 28 moves, so that it can be guided over its entire length. In addition, this ensures that the armature 28 cannot tilt, which would otherwise lead to high magnetic radial forces on the armature 28 and thus to high friction with respect to the pole tube 12. The sleeve 29 is sealed by means of an annular sealing element 56 which is arranged between a collar 58 of the sleeve 29 and the housing 46 and rests in a sealing manner on the end cover 42 and part of the pole yoke 50.

According to an embodiment not shown, the pole tube 12 and the pole core 14 can be made in one piece. The sleeve 29 can be omitted in this case and the armature 28 is designed to be displaceable in the axial direction pointing towards the pole core insert.

The bearing bush 26 has recesses 32 arranged in the axial direction for equalizing pressure between the armature space 60 and the outer space 54 of the central actuator 10. The pressure equalization ensures a volume equalization of the enclosed hydraulic fluid or the enclosed air between the armature space 60 and an outer space of the central actuator 10. Such a pressure equalization is important both during dry operation, that is to say when the armature space 60 is filled with air, and also during operation with hydraulic fluid in the armature space 60.

On its side facing the armature 28, the bearing bush 26 has a collar 40 as a stop for the armature 28 during its axial movement. Such a fixed stop keeps the end face of the armature 28 at a certain distance from the disc-shaped pole core insert 22 and thus prevents the armature 28 from sticking to the end face of the armature 28 on the pole core insert 22. Gluing would change the movement behavior of the armature 28 and the Significantly influence the magnetic forces required to operate the armature 28, so that the entire dynamic behavior of the central actuator 10 would be changed as a result. Therefore, such a collar 40 as an anti-adhesive disk can positively influence the dynamic behavior and the energy consumption of a central actuator 10 which is operated with magnetic forces.

The actuating tappet 20 can be pressed into a central bore 30 of the armature 28. If the actuating plunger 20 is made of a different material than the armature 28, this represents a favorable solution for connecting the two components. The pole yoke 50, which can be formed from several plates and / or tubes, encloses the coil 52 on its outer sides, as a result of which the coil 52 is surrounded as completely as possible by magnetic material, since the pole tube 12 is formed inside the coil 52. As a result, the magnetic flux generated by the coil 52 is concentrated as favorably as possible on the volume area in which the armature 28 can move.

A pressure equalization between a front and a rear side of the armature 28 is made possible by the fact that the actuating tappet 20 between the armature 28 and the bearing bush 26 has one or more transverse bores 71 which lead into a central longitudinal bore 72 leading into the bore 30 of the armature 28 open out, so that the armature 28 is acted upon by the same hydraulic pressure on both sides.

The armature 28 can also be mounted by means of a two-point mounting, as is described for a subsequent exemplary embodiment.

Fig. 3 shows a section through a central actuator 10 'according to a second embodiment of the invention. This differs from the first exemplary embodiment only in that the armature 28 'and the actuating tappet 20' are made in one piece. The two in Fig. 4 The components shown are made of the same material and the actuating plunger 20 ', like the armature 28', can be made of a soft magnetic material. A central actuator 10 ′ which is as compact as possible can thus be constructed.

A guide surface 66 on an end of the armature 28 ′ facing away from the closing element 18 is polygonal in the form of a diameter shoulder 75 and has circumferentially uniformly distributed flat areas 68, through which a pressure equalization between the front and the rear side of the armature 28 ′ is made possible.

The diameter shoulder 75 serving as a guide surface 66 forms a first bearing point of the armature 28 '. The second bearing point of the armature 28 'is the bearing of the actuating pin 20' in a stepped recess 70 of the bearing bush 26, which especially in Fig. 2 can be seen. This two-point bearing with a large bearing spacing allows the armature 28 'to be guided well, since small coaxial errors from an outer diameter of the pole core insert 22 to an inner diameter of the bearing bush 26 and from an armature outer diameter and an outer tappet diameter can be compensated for.

The Figures 5 and 6 a further exemplary embodiment of the invention can be seen, which differs from the first exemplary embodiment essentially in the design of the pressure equalization between the front and the rear of the armature 28 ″.

As also described for the first exemplary embodiment, the actuating tappet 20 ″ is pressed into a central bore 30 ″ of the armature 28 ″. In contrast to this, the essentially cylindrical actuating tappet 20 ″ in the press-in area has flattened areas 73 which are, for example, milled or turned to represent a volume or pressure equalization between the front and the rear of the armature 28 ″. The exemplary embodiment shown has, by way of example, three flat areas 73 distributed around the circumference.

Like in particular from Fig. 6 As can be seen, which shows the armature 28 "with the pressed-in actuating plunger 20" in an enlarged view in section, the flattened areas 73 extend on both sides beyond the press-in area of the bore 30 ". In order to design the actuating plunger 20" without a tip and thus cost-effective production To enable, the flats 73 do not extend to one end 74 of the actuating plunger 20 ″. The bore 30 ″ is stepped and has an enlarged inside diameter beginning in the area of the flats 73 in order to compensate for volume via the flats 73 and the end 74 to enable. As a result, there is no need for axial bores in armature 28 ″ or longitudinal flattened areas on the outside of armature 28 ″, which are expensive to provide on the armature and also have a negative effect on the magnetic force.

In order to provide the advantageous two-point support described above, the armature 28 ″ has a cylindrical diameter shoulder 75 ″ in one end region, which, with an enlarged outer diameter, forms the guide surface 66 ″.

List of reference symbols

10, 10 ', 10 "

Central actuator

12th

Pole tube

14th

Pole core

18th

Finishing element

20, 20 ', 20 "

Actuating tappet

22nd

Pole core insert

24

drilling

26th

Bearing bush

28, 28 ', 28 "

anchor

29

Sleeve

30, 30 "

drilling

32

Recess

40

Federation

42

End cover

43

drilling

46

casing

50

Poljoch

52

Kitchen sink

54

Outside space

56

Sealing element

58

Federation

60

Anchor room

62

head Start

64

drilling

66, 60 "

Guide surface

68

Flats

70

Recess

71

Cross hole

72

Longitudinal bore

73

Flattening

74

end

75, 75 "

Diameter shoulder

L.

direction

Claims (15)

1. Central actuator (10, 10', 10"), in particular for a solenoid valve of an oscillating motor camshaft adjuster, comprising a housing (46) which encloses the central actuator (10, 10', 10"), a pole tube (12) and a pole core (14) which are arranged within at least one coil (52) which generates a magnetic field, and an actuating tappet (20, 20', 20") which is arranged on an armature (28, 28', 28") which is configured such that it can be displaced in the axial direction (L) in an armature space (60), a termination element (18) for closing the armature space (60) being provided, which termination element (18) comprises at least one pole core insert (22), with a central bore (24), and a bearing bush (26) which is arranged in the central bore (24) of the pole core insert (22), the actuating tappet (20, 20', 20") being arranged axially displaceably in the bearing bush (26), the termination element (18) comprising, furthermore, a termination cover (42), characterized in that the termination element is provided as a unit which can be preassembled, the termination cover (42) having a central bore (43), in which the bearing bush (26) is arranged, and the bearing bush (26) being produced by way of a plastic injection moulding method, the termination cover (42) and the pole core insert (22) being provided as insert parts which are provided such that they are encapsulated by the material of the bearing bush (26) in the region of the central bores (24, 43).
2. Central actuator (10, 10', 10") according to Claim 1, characterized in that the bearing bush (26) has recesses (32) which are arranged in the axial direction (L) for pressure equalization between the armature space (60) and the outer space (54) of the central actuator.
3. Central actuator (10, 10', 10") according to either of the preceding claims, characterized in that, on its side which faces the armature (28), the bearing bush (26) has a collar (40) as a stop of the armature (28, 28', 28") during the axial movement of the latter.
4. Central actuator (10, 10") according to one of the preceding claims, characterized in that the actuating tappet (20, 20") can be pressed into a central bore (30, 30") of the armature (28, 28").
5. Central actuator (10, 10") according to one of the preceding claims, characterized in that the actuating tappet (20, 20") is formed from a magnetically soft material.
6. Central actuator (10) according to one of the preceding claims, characterized in that, for pressure equalization between a front side and a rear side of the armature (28), the actuating tappet (20) has one or more transverse bores (71) between the armature (28) and the bearing bush (26), which transverse bore or bores (71) opens/open into a central longitudinal bore (72) which leads into the bore (30) of the armature (28).
7. Central actuator (10") according to one of the preceding Claims 1 to 5, characterized in that the actuating tappet (20") has flattened portions (73) which extend on both sides beyond the press-in region of the bore (30"), and the bore (30") is of stepped configuration and has an enlarged internal diameter which begins in the region of the flattened portions (73).
8. Central actuator (10') according to one of the preceding Claims 1 to 3, characterized in that the actuating tappet (20') and the amateur (28') are provided in one piece.
9. Central actuator (10, 10', 10") according to one of the preceding claims, characterized in that the armature (28, 28', 28") is configured such that it can be displaced in a non-magnetic sleeve (29) in the axial direction (L) which points onto the pole core insert (22) .
10. Central actuator (10, 10', 10") according to one of the preceding Claims 1 to 8, characterized in that the pole tube (12) and the pole core (14) are configured in one piece, and the armature (28, 28', 28") is configured such that it can be displaced therein in the axial direction (L) which points onto the pole core insert (22) .
11. Central actuator (10', 10") according to one of the preceding claims, characterized in that, at an end which faces the termination element (18), the armature (28', 28") has a diameter shoulder (75, 75") as guide face (66, 66") for guidance in the armature space (60).
12. Central actuator (10') according to Claim 11, characterized in that the guide face (66) of the armature (28') is of polygonal configuration, and has flattened portions (68) which are distributed uniformly around the periphery for pressure equalization between a front side and a rear side of the armature (28').
13. Central actuator (10") according to Claim 11, characterized in that the guide face (66") of the amateur (28") is provided as a cylindrical diameter step (75") with an increased external diameter.
14. Central actuator (10, 10', 10") according to one of the preceding claims, characterized in that the housing (46) is produced by way of a plastic injection moulding method.
15. Central actuator (10, 10', 10") according to Claim 14, characterized in that the termination cover (42) is provided such that it is fastened to the housing (46) by means of ultrasonic rivets.

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