The invention relates to an electromagnetic actuating unit for a hydraulic directional control valve according to the preamble of claim 1, and to a method for the assembly thereof.
Such directional control valves are used for example in internal combustion engines for the actuation of hydraulic camshaft adjusters.
DE 103 00 974 A1 discloses a proportional solenoid valve of a camshaft adjuster device for motor vehicles. The proportional solenoid valve has a valve housing in which a piston is slidable and which has a plurality of ports via which hydraulic oil can be supplied. The proportional solenoid valve also comprises an electromagnet part by means of which the piston can be adjusted via a plunger. The plunger is mounted in an axial bore in a housing of the electromagnet part, whereby it can slide axially.
DE 102 11 467 A1 presents a camshaft adjuster having an electromagnet which is designed as a repelling proportional magnet. The proportional magnet has a magnet armature which is fixedly seated on an armature plunger guided through a pole core and which bears with a free end surface against a control piston or against a part fixedly connected thereto.
DE 101 53 019 A1 presents an electromagnet which is suitable in particular as a proportional magnet for actuating a hydraulic valve. The electromagnet comprises a hollow cylindrical coil body which is delimited by an upper pole shoe and a lower pole shoe. The electromagnet is surrounded by a magnet housing. The coil body acts magnetically on a magnet armature which transmits the magnetic force onward via a plunger rod for actuating the hydraulic valve. The plunger rod is mounted in an axial bore in the lower pole shoe, whereby it can slide axially.
DE 10 2004 057 873 A1 relates to a seat valve having a line system for conducting through an inflowing medium. The seat valve has a seat and an adjustable closing element in the line system. The adjustable closing element is actuated by means of an electromagnetic actuating device. The electromagnetic actuating device comprises an armature housing in which an armature is arranged so as to be adjustable in the direction of a coil axis. The armature is connected to an actuating element which actuates the closing element. The actuating element is mounted in an axial bore in the housing of the electromagnetic actuating device, whereby it can slide axially.
DE 10 2005 048 732 A1 relates to an electromagnetic actuating unit of a hydraulic directional control valve. The electromagnetic actuating unit comprises an armature, which is arranged in an axially slidable manner within an armature chamber, and a pole core, which is arranged in a receptacle and delimits the armature chamber in one movement direction of the armature. Furthermore, the electromagnetic actuating unit comprises a coil which is preferably encapsulated with a non-magnetizable material so as to form a coil body. The armature is mounted in a sliding sleeve, whereby it can slide axially with low friction.
JP 2005-188630 A presents a hydraulic directional control valve having an electromagnetic actuating unit. The electromagnetic actuating unit comprises a coil for generating a magnetic field which acts on an axially slidable armature. The armature comprises an actuating element which actuates the hydraulic directional control valve. The actuating element is mounted in an axial bore in the housing of the electromagnetic actuating device, whereby it can slide axially.
It is the object of the present invention, taking the electromagnetic actuating unit shown in
The object is achieved by means of an electromagnetic actuating unit having the features of claim 1 and by means of a method for the assembly thereof having the features of method claim 8.
The electromagnetic actuating unit according to the invention serves for the adjustment of a hydraulic directional control valve, for example for variably adjusting the control times of an internal combustion engine. The electromagnetic actuating unit initially comprises, as is known, a coil by means of which a magnetic field can be generated. The actuating unit also comprises an armature unit having an armature and a pressure pin. The pressure pin forms an actuator of the electromagnetic actuating unit. By means of the pressure pin, the hydraulic directional control valve can be acted on so as to be adjusted. For this purpose, the armature unit is mounted, so as to be slidable along its axis, in two bearing points.
Said axis is conventionally formed by an axis of symmetry of the armature unit, which in a typical ideal design of electromagnetic actuating units is identical to the axis of symmetry of the armature and/or the coil. To slide the pressure pin axially, the armature acts on the pressure pin, which predefines the axial sliding movement. The armature and the pressure pin perform the axial sliding movement jointly. The armature is situated in the magnetic field of the coil, as a result of which said armature is acted on by a magnetic force which causes the sliding movement. The pressure pin follows the axial sliding movement of the armature on account of the fixed connection thereto.
The armature unit is mounted in two bearing points. Here, a first bearing point is provided in a yoke unit in which the armature is mounted so as to be axially slidable. A second bearing point provided in a pole core unit serves as a bearing arrangement for the pressure pin fixedly connected to the armature. The pressure pin is guided through said second bearing point. The hearing arrangement permits an axial sliding movement of the pressure pin, that is to say a movement in the direction of its longitudinal axis.
In another embodiment, the pressure pin is mounted in both bearing points and is guided through and fixed in a central bore of the armature, such that the armature is fixedly mounted on the pressure pin. The method according to the invention can be applied particularly advantageously in said embodiment because the pressure pin itself forms the longitudinal axis of the armature unit and at least the armature, as a tolerance-afflicted part, does not form a part of the bearing arrangement.
According to the invention, at least one of the two bearing points is in a radially free, that is to say “floating,” state during assembly. During assembly, the two bearing points are coaxially aligned with one another and the free bearing point is subsequently fixed. The fixing may take place for example by means of adhesive bonding, soldering, welding, stamping, crimping or clamping.
In a preferred embodiment of the invention, the alignment of the hearing points is realized by means of a centering sleeve which is inserted as a centering aid into the coil and in which the bearing points are aligned coaxially with the longitudinal axis of the armature unit. It is however likewise possible to realize the alignment of the bearing points by means of an assembly device which performs the alignment.
The coil is preferably arranged within a coil body and has a hollow cylindrical basic shape. The armature, a yoke unit with a yoke and cover, and a pole core unit with a pole core and a magnet housing are preferably arranged in the cavity of the hollow cylindrical basic shape of the coil body. Efficient functioning, a compact design and cost-effective assembly of the electromagnetic actuating unit are ensured in this way. Here, the armature, the yoke and the pole core are of rotationally symmetrical design, wherein the axes of rotation of the hollow cylindrical basic shape of the coil body, of the armature, of the yoke and of the pole core coincide. Said axes of rotation form the axis of the electromagnetic actuating unit, in which the armature moves with the pressure pin in a translatory fashion.
The coil body is preferably held, with its lateral surface and a base surface, in a positively locking manner by the housing. Secure assembly of the coil body relative to the hydraulic directional control valve is ensured in this way, such that large forces for adjusting the hydraulic directional control valve can be transmitted.
The electromagnetic actuating unit according to the invention is particularly suitable for the actuation of a hydraulic directional control valve designed as a central valve. The central valve is arranged radially within an inner rotor of a device for variably adjusting the control times of an internal combustion engine. Such actuating units are also referred to as a central magnet. The electromagnetic actuating unit according to the invention is however also suitable for adjusting other hydraulic directional control valves, for example also in applications other than internal combustion engines.
Further advantages, details and refinements of the present invention will emerge from the following description of preferred embodiments, with reference to the drawing, in which:
The plurality of embodiments of the electromagnetic actuating unit according to the invention which will be described in
The armature 09 and pressure pin 11 form an armature unit. The armature unit may also be formed in one piece in modified embodiments. The yoke 04 and the yoke plate 06 form a yoke unit which is preferably preassembled. The pole core 07 and the housing 08 form a pole core unit.
In all of the following figures, the structural difference in relation to the embodiment according to the prior art illustrated in
In the embodiment illustrated in
In the embodiment illustrated in
In the embodiment illustrated in
In the illustration of
Another preferred embodiment is shown in
In the embodiment illustrated in
A further assembly option is for the pole core 07 to be mounted in a floating fashion during assembly, as shown in
Number | Date | Country | Kind |
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10 2008 059 012.6 | Nov 2008 | DE | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/EP2009/063646 | 10/19/2009 | WO | 00 | 5/23/2011 |