JPH0344010A - Electromagnetically operating actuator - Google Patents

Abstract

PURPOSE: To provide an actuator, which reduces energy cost and automatically attains specified end position when switch off or stop for failure by providing a permanent magnet and electromagnet at a closed position and an opening magnet having an electromagnet only. CONSTITUTION: The actuator comprises working magnets 1, 2, coils 3, 4 and a permanent magnet 5. The current in the coil 3 of a closing magnet 1 weakens the magnetic field action of the permanent magnet 5 on an armature 6. At time t1 with specified current level, the force of a pre-compressed compression spring 10 is higher than the holding force by the magnet 1 sufficient to move the armature 6 and valve shaft 8. At time t2 to feed a current to the coil 4 of the opening magnet 2 at correct timing, the actuator is attracted to a pole face. After cutting off the current to the coil 4, a short delay time elapses while the magnetic field weakens the spring force. At time t3 the actuator moves and at time t4 due to the magnet force it is attracted and held, based on a magnetic field generated by the permanent magnet.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention comprises a spring system and two electrically actuated switching magnets, hereinafter referred to as actuating magnets, which actuate the control. Smooth-sliding valves, in particular for control elements capable of oscillatory movement in positive displacement machines, in which the armature operating the element can be moved into two opposite switching positions, and the balance position of the spring system lies between the two switching positions. and relates to electromagnetically actuated actuators for stroke valves.

[Conventional technology]

Such an actuator is described in West German Patent Application No. 30
It is known from the publication No. 24109. In this type of actuator, the control element of the positive displacement machine is held closed by a compression spring.

Another compression □ spring acts on the magnet armature, cooperating with the control element, such that the balance position of the spring system is located between the end positions of the armature's movement.

Each end position of the armature movement lies on an electrically operated switching magnet (hereinafter referred to as actuating magnet).

To switch this actuator, one actuating magnet is energized in each case and the other actuating magnets are de-energized. Due to the force of the pre-compressed spring, the armature is accelerated to the balance position and is decelerated on the further path by the counteracting force of the other spring. The armature cannot reach other end positions due to friction. The armature is attracted by the pulling force of the actuating magnet in the remaining travel path.

In the case of other known devices, the reactivation magnets are each associated with a permanent magnet, as is described, for example, in DE 35 00 530 A1, or
As described in DE 34 02 768 A1, a common permanent magnet is provided for the reactivation magnets, thereby holding the armature in each magnet without exciting the coils. I can do it. The separation of the armature from the pole face of the magnet is carried out by exciting the coil of the respective magnet with the pole face of the direct current. This pole face weakens the magnetic field of the permanent magnet.

By the means described in West German Patent Application No. 3500530, West German Patent Application No. 302410
Energy can be saved compared to the actuator that does not use a permanent magnet, which is known from Japanese Patent No. 9.

However, systems with one common permanent magnet for the reactuating magnet are not suitable for use as quick and compact actuators due to the high armature weight and low axial pulling force.

Furthermore, in the case of an actuator with one permanent magnet for each working magnet, when the permanent magnet is used as an open magnet, it is possible to pull the armature toward the magnetic pole face of the open magnet and to separate the armature from this magnet. between
It has been found that it is not possible to adjust the critical times for load control of internal combustion engines sufficiently short. As a result, it is not possible to set short control times in order to achieve low loads on the internal combustion engine. On the other hand, on the side of the closing magnet, in the case of a four-stroke internal combustion engine, a sufficiently long time is provided, so that it makes sense to use permanent magnets.

Another disadvantage of actuators with one permanent magnet per working magnet is that the two end positions of the magnet armature can be approximately the same when the actuator is stopped or switched off. Thereby,
For example, a control valve in an internal combustion engine may remain open or closed, which must be known by electronic control.

Furthermore, when supplying energy to the actuators via two conductors per actuating magnet for multi-cylinder internal combustion engines, high requirements are placed on the reliable and compact installation and connection of the conductors.

[Problem of invention]

The object of the invention is to provide a high-speed internal combustion engine with particularly variably actuated control elements, which requires low energy costs and in which a predetermined end position is automatically achieved upon switch-off or a breakdown. The purpose of the present invention is to provide an actuator for driving the vehicle.

[Means to solve the problem]

This object is solved in that the actuator of the type mentioned at the outset comprises a permanent magnet and an electromagnet in the closed position, and the open magnet comprises only an electromagnet.

[Other inventions and their effects]

In order to save maximum electrical energy, the permanent magnets are formed in such a way that they can attract and hold the armature from a position near the pole faces during oscillating motion.

In another embodiment of the invention, the permanent magnets are dimensioned in such a way that they only allow the holding of the armature in the pole faces of the closing magnet, and for the attraction of the armature assistance is required by the magnetic field of the electromagnet.

A reduction in the number of cables leading to the actuator is achieved, according to another embodiment of the invention, by a parallel connection of both types of magnets, taking into account the electrical polarity.

In order to arrange a permanent magnet that allows the armature to be held against the pole face of the magnet, it is possible to ensure that the armature reaches a balance position between the working magnets during a fault stop or switch-off. In order to move the armature towards one of the actuating magnets starting from the balance position, both coils are excited at the natural frequency of the specifically vibrating spring-mass system.

In order to incorporate a permanent magnet within a cylindrical magnet with low remanence, in another embodiment of the invention a location within the inner magnet leg is selected. This is because damage can be prevented.

Furthermore, it is desirable that the magnetic circuit of the permanent magnet and the magnetic circuit of the electromagnet attached in the closed position are completely or partially separated.

〔Effect of the invention〕

The advantage achieved by the invention is, inter alia, that the actuator can be operated with short dwell times in the open magnet, ie with short dwell times in the open position of the control valve. Furthermore, when the system fails or is switched off,
A predetermined end position is reached and, in the case of an internal combustion engine, the control valve assumes a closed position. Furthermore, with proper arrangement and connection of the electromagnets, it is possible to supply power to the actuator via two common conductors. This cuts the cost of electronic control in half.

〔Example〕

Embodiments of the present invention will be described in detail based on the drawings.

FIG. 1 illustrates an electromagnetically actuated actuator (electromagnetically actuated operating device). This actuator comprises actuating magnets 1, 2, coils 3, 4 and permanent magnets 5.

The armature (pole piece) 6 is guided in a sleeve 7. Permanent magnet 5 is made of rare earth cobalt or rare earth iron boron sintered material, given the high requirements imposed here. This material is very brittle and therefore easily damaged.

The installation point between the sleeve 7 and the coil 3 shown in Figure 1 (filled with casting compound)
guarantees optimum protection against destruction.

In the illustrated position number 1 of the armature 6, the armature is held by the magnetic field of the permanent magnet 5. The shaft 8 of the actuator of the positive displacement machine, for example the valve shaft, is in this position held in the closed position by the compression spring 9. Starting from this valve position, FIG. 2 shows the control of the coil during the stroke movement, if the arrangement of the permanent magnets 5 makes it possible to attract and hold the armature. The current in the coil 3 of the closing magnet 1 weakens the magnetic field action of the permanent magnet 5 on the armature 6. For a given current level, at time t1 the force of the precompressed compression spring 10 is greater than the holding force of the magnet 1;
The armature 6 and the valve shaft 8 are moved. Since current is applied to the coil 4 of the open magnet 2 at the correct time, the armature is attracted to the magnetic pole face at time t2. After interrupting the current to the coil 4, a short delay time elapses, during which the magnetic field becomes weaker than the spring force, and at the time t, the armature 6 moves and, under the action of the force of the magnet 1, the permanent magnet It is attracted and held at time t4 based on the generated magnetic field.

FIG. 3 shows the process for a permanent magnet arrangement that allows the attraction of the armature only with the additional assistance of the magnetic field generated by the coil. In the case of this stroke, in addition to the above-mentioned sequence for drawing the armature 6 to the magnet l, between the times t3 and t4 the coil 3
need to be excited. The coil must alternate poles on its downward stroke to generate a magnetic field to assist the permanent magnet.

FIG. 4 shows the current course occurring during the stroke movement when the coils 34 are connected in parallel for the case of attraction and holding without current assistance by the coil 3. At this time, after increasing the current in the coil 3 to lower the armature 6 of the magnet 1, current is applied to both coils before tl.

At this time, the coils 4 are arranged as follows. That is, the arrangement is such that at time t2 when the armature approaches the pole face of the magnet 2, the current reaches a level sufficient to attract the armature 6. The range of the current curve indicated by the notching is not necessary for the functioning of the actuator, but the current flows in the catch of the armature until time t2 due to the parallel connection of the coils.

FIG. 5 shows the current course that occurs when drawing in with the current assistance provided by the coil 3.

In this case, the coils 3.4 are arranged as follows.

That is, the current in the coil 3 changes to the armature 6 at time t.
is arranged such that the current in the coil 4, which has been turned on at the same time, has a sufficient level for armature proximity to pull armature J-76 at time t2.

Upon return of the armature 6, after time t3, the current direction to the coil is reversed. The lower region of the current curve, indicated by the hatching ■, is not necessary for the function of the actuator, but is caused by the parallel connection of the two coils. The resulting losses are reduced by proper arrangement of the coils.

FIG. 6 shows the oscillation initiation process for an actuator with a permanent magnet 5 in the closing magnet l starting from the balance position. Line 20 shows the stroke of an actuator, for example of a valve in an internal combustion engine, and line 2122 shows the current course of an electromagnet that belongs to the closing or opening function.

The application of current to the coil 4 produces a magnetic pull force on the magnet 2. This magnet attracts the armature 6 based on it. However, due to the large spring force and the lack of kinetic energy, the armature is not drawn back until it reaches a predetermined end position, and after reaching the first extreme value 23 it oscillates back. This excited vibration has a period corresponding to the natural frequency of the spring-mass system. continue,
The current to the coil 4 is cut off, and the current is turned on to the coil 3. In this case, the current in the coil 3 is polarized such that the magnetic field of the permanent magnet is strengthened. After repeating this process several times, the armature reaches the magnet 1 during deflection 24 and is held there. This holding is carried out until a current of opposite polarity in the coil 3 weakens the magnetic field of the permanent magnet and causes the armature 6 to lower.

In FIG. 7, an actuator with an upper actuating magnet 30 is shown. A permanent magnet circuit consisting of a permanent magnet 31, a pole piece 32 and a central leg 33 is connected by a common central leg 33 to a separate circuit of electromagnets consisting of an outer leg 34, a yoke 35 and a coil 36. . The permanent magnet circuit 31, 32, 33 has two axial gaps. A tensile force acts on the armature 37 through this gap. The electromagnetic circuit 33, 34, 35, 36 has an axial gap and a radial gap 38. By energizing the coil 36 of the actuating magnet 30, depending on the electrical polarity, the magnetic flux density in the permanent magnet energized central leg 33 is strengthened or weakened.

4 4° Therefore, the armature 37 is assisted in being pulled against the force of the spring 39, and the movement of the armature is started. When the magnet circuit is opened, i.e. when the armature 37 contacts the lower actuating magnet 40, the permanent magnet circuit is replaced by the two axial air gap structure of FIG. It does not become weaker than in the case of . Nevertheless, by utilizing the central leg 33, a large holding force is applied in the drawn state.

[Brief explanation of drawings]

FIG. 1 shows a longitudinal section through an embodiment of the device according to the invention with a permanent magnet in the inner leg of the cylindrical magnet; FIGS. 2 and 3 show the two electromagnets when operated with separate conductors. Diagrams 4 and 5 schematically showing the current course of the coil and the course of the valve stroke
The figure schematically shows the current course of the coils of both electromagnets and the course of the valve stroke when operating with a common conductor, and Figure 6 shows the flow of the coils of both magnets when the system starts vibrating at its natural frequency. FIG. 7 schematically shows the current course and the course of the valve stroke; FIG. 7 is a longitudinal sectional view of an embodiment of the device with a partially separated magnet circuit of a permanent magnet or electromagnet; 1.2... Working magnet, 5... Permanent magnet, 6...
Armature, 8... Control element, 9.10... Spring

Claims (7)

[Claims] 1. a spring system and two electrically actuated switching magnets, hereinafter referred to as actuation magnets, by means of which an armature for actuating a control element can be moved into two opposing switching positions; In electromagnetically actuated actuators for control elements capable of oscillatory movement in positive displacement machines, in particular for plain and stroke valves, the balance position of which is between the two switching positions, on the actuating magnet belonging to the closing function. An electromagnetically actuated actuator, characterized in that, in addition, a permanent magnet is provided and the actuating magnet belonging to the opening function is designed exclusively or primarily as an electromagnet. 2. 2. An electromagnetically actuated actuator according to claim 1, characterized in that the magnetic circuit of the permanent magnet and the magnetic circuit of the electromagnet attached in the closed position are completely or partially separated. 3. Claim 1 or Claim 2, characterized in that the coils of both working magnets are connected in parallel in consideration of polarity.
Electromagnetic actuator as described. 4. characterized in that the attractive force of the permanent magnet is determined such that when no current is flowing through the coil, the armature can be attracted to and held by the magnetic pole surface of the working magnet that cooperates with the permanent magnet; The electromagnetic actuator according to any one of claims 1 to 3. 5. The attractive force of the permanent magnet can hold the armature on the magnetic pole face of the working magnet that cooperates with the permanent magnet when no current is flowing through the coil, and can assist in drawing the armature by excitation of the working magnet's coil. Claims 1 to 3 are characterized in that
An electromagnetic actuator as described in any one of the above. 6. 6. An electromagnetically actuated actuator according to claim 1, wherein the permanent magnet is housed in the inner leg of the actuating magnet, which is designed as a cylindrical magnet. 7. 7. Electromagnetically actuated actuator according to claim 1, characterized in that the coil of the actuating magnet can be excited at a frequency that corresponds to the natural frequency of the vibrating system.