KR20020070422A - Electromagnetic rams - Google Patents

Abstract

An electromagnetic ram in the form of a cylindrical magnet assembly 11 is installed to receive the interacting armature to move along the length of the cylinder. The armature 12 is provided with a member 14 extending laterally through an axially extending slot 15 of the cylinder 11 to transfer the armature's movement out of the ram.

Description

Electromagnetic RAM {ELECTROMAGNETIC RAMS}

Known such rams are of various constructions but usually they are all variations of piston and cylinder arrangements with output coaxial to the centerline of the ram. This presents a difficulty when used in confined spaces because either the entire stroke can be used or it means that a portion of the ram requires twice the length of the stroke to be accommodated when installed in the recess. This difficulty causes the electromagnetic ram to be limited in its use.

Summary of the Invention

SUMMARY OF THE INVENTION The present invention provides an electromagnetic ram wherein a member extending laterally in the axial direction is used to transmit the movement of the armature through the axially extending slot to the outside of the ram.

In one embodiment, the ram is in the form of a stator provided with a coil that interacts with the magnetic field generated by the magnet assembly on the armature and generates movement when a voltage is applied. This requires the coils to be wound in the same way as to form a gap in which the transverse member can move alternately.

Preferably, each coil is wound as a pair of coil sections approaching the "shape of eight" so that the coils can be energized by signals out of phase with each other, for example to form three phase drives at 120 °. It is connected to three sets.

In another embodiment, the ram is in the form of a stator provided with a permanent magnet to produce alternating magnetic poles of a fixed field and an armature having one or more coils wound on the armature.

In this embodiment, the coils are conventional coils, but require the provision of a unique connector to power the coil, for example in the form of a flexible bend.

Advantageously, if the permanent magnets of the stator are provided with pole pieces in the form of slotted discs, the pole pieces are preferably shaped to provide a magnetic field of a predetermined shape.

In order that the present invention may be more readily understood, the embodiments will be described with reference to the accompanying drawings.

The present invention relates to an electromagnetic ram.

1 is a cross-sectional view of a first embodiment of an electromagnetic ram according to the present invention;

2 is a cross-sectional view of the ram shown in FIG. 1;

3 is a schematic view of a coil formed by a pair of coil sections; And

4 is a schematic side view of another embodiment of the present invention.

Referring to FIG. 1, the electromagnetic ram includes a cylindrical stator 11 formed of a steel outer tube on which the armature 12 is mounted to move along the length of the stator 11.

The armature 12 is shorter than the stator 11 and is provided with a laterally extending member 14 which can take any convenient force but is shown here as an axial elongated pin 14. . The pin 14 is received in an axially extending slot 15 provided in the wall of the stator 11.

The armature 12 consists of one or more assemblies of permanent magnet members 17 magnetized and interposed axially between two pole pieces 18. If desired, the pole pieces will taper towards their radial edges to reduce the mass of the field and also the armature in the core. It is also possible to insert a thin flexible disk between the pole pieces of adjacent magnet assemblies. This allows for manufacturing tolerances and also allows a ram with long stators to use an armature with multiple magnet assemblies.

Within the steel outer tube, the stator is provided with a special winding coil that leaves a gap through which the member 14 extends. As shown in the third, one way of achieving this is to wind each coil in the form of two coil portions in the form of a "8 shape". The coils are assembled into three sets (a pair of coil sections for each three phase because of each magnet period). Since the current in every phase must be alternating in direction, the coils are wound without crossing the gap of the axially extending slot 15 in the stator. The magnet assembly or assemblies protrude radially outwardly through the coil of the stator.

The interior of the stator 11 is preferably aligned with a dielectric tube with hard slots that serves as bearing and seal surface. The armature 12 is provided with a bearing or surfaces, for example in the form of a piston ring which is installed to slide along the rigid dielectric tube.

Each assembly of the permanent magnet members 17 interposed between the pole pieces 18 is preferably circular in axial cross section. Since the armature 12 can be formed of multiple assemblies, it is possible to allow relative pivot movement between each assembly or between groups of assemblies facing around the central axis. Therefore, the armature supported on a series of bearing-rings that slide on stator lining tubes made of hard dielectric material is followed by irregularities in the axis of the cylinder and even lead to significant curvature. This is an important advantage when it is desired that the ram bend upwards or around obstacles. It also provides tolerances to structural mismatches caused by mechanical stress, temperature gradients or damage. Flexible disks between assemblies are sufficient to provide the required amount of relative movement, but other more complex coupling devices will be used depending on the application. In addition, the pin 14 needs to be articulated or the connection between the armature 12 and the pin 14 needs to be articulated.

Due to this fundamental electromagnetic structure, it is possible to forth numerous other actuators. For example, if the stator is a closed cylinder, for example, if the tube shown in FIG. 1 is provided at the sealed end, and the actuator is equipped with a circumferential seal and thus forms a piston, the rodless pneumatic actuator may It may be formed when the interior is filled with gas, for example air, which may be supplied from a fixed or variable pressure source. This in turn requires a sliding pressure seal 16 provided with a slot 15. Otherwise, the slot 15 needs to be provided with a protective seal against dust and other contaminants.

In addition, the shape of the cylinder need not be limited to a circular cross section, but may be elliptical to ensure that pin 14 truly travels below the center of the slot and permits side forces.

In addition, the slotted stator can be curved by itself and will allow the armature's pins to move in an arc of circumference if curved at a uniform radius. In this structure, it would be necessary to use flexible disks between each magnet assembly, given the fact that the armature slides against the lining tube provided on the stator. As a result, when the pin 14 is replaced by a radius arm or coupled to the arm, the arm is connected to an orthogonal shaft, with the result that forces on the armature exert a torque on the shaft. It will be appreciated that for this means high torques can be generated directly with minimal movement. In addition, if the arc continues in perfect circumference around the shaft in question, this allows the armature to extend to fill the entire stator, thus creating the maximum possible torque. The armature will then be caused to rotate continuously if necessary. This in turn forms a toroidal rotating motor that can be used for accurate angular positioning of optics or other special devices.

In addition, more than one ram may be used to achieve movement of a single member. That is, it can be mounted or connected on either side of a common actuator member that can have an extension projecting out of the housing. The total length of the system need not be longer than the length of the ram, but can be several times the output of a single ram as well.

This embodiment is described as a RAM having a permanent magnet armature and operating as a three phase synchronous machine. Other structures are possible, such that the armature uses coils and the stator is formed of permanent magnets. 4 schematically shows one form of a ram having such a structure. Here, the armature 12 is formed of a number of conventional coils 20 wound on the steel coil 21, the coils having a derailing lead of sufficient length to allow the armature to move along the stator. Power is supplied by 22.

The stator 11 is formed by a number of permanent magnet sections that are stimulated to form alternating pole pieces along the length of the stator 11. Each permanent magnet section 24 consists of a permanent magnet 24a and a pole piece 24b. It is desirable to form the pole pieces 24b so that they form an appropriate magnetic field. In this case they are evenly tapered towards the circumference of each section of the permanent magnet. This results in the reduction of a strong magnetic field around the outside of each section 24.

Slots are each formed in the sections 24 and the slots are aligned to allow the transversely drawn pins (not shown) attached to the armature 12 to move freely with the armature as in the first embodiment.

It is also possible to construct a coil in order to form the stator or armature as needed. In this technique, when applied to the stator, the stator can be formed from a stock of flat steel rings that are separated from each other by a cylinder steel ring to form a generally continuous steel cylinder. Each copper coil is fitted in a slot between flat iron rings, respectively, and is appropriately energized to provide axially alternating magnetic poles. The steel structure may be replaced with castings and / or metal components. In addition, the stator will be designed to induce eddy currents in the passive armature to produce a low cost machine suitable for opening the door or moving the curtain.

One particular use of the ram as described is an elevator in which a ram with two or four slots can be arranged against the inner wall of the elevator shaft, which quietly, directly and accurately drives and guides the cage.

It will be appreciated that many uses of the actuator require the presence of a position detector that provides a feedback signal to the control unit in order to properly control the relative movement of the actuator by proper switching of the stator coils. This is not shown in the figures but the position will usually depend on the use in which the actuator is placed and the actual structure of the actuator.

In the case of an elevator, the cage's own weight and its load are supported by the gas in the stator. The exact value of this pressure is automatically adjusted by the small valve system and the small precompressor. The gas pressure is controlled by a simple algorithm that integrates the value of the current applied to the actuator to compensate for temperature variations, lenses, load variations and elevator parking devices. Since air is not consumed during elevator motion, the compressor does not have to be large.

For example, long stators are considered as lifts, but stator coils must be divided into relatively short sections. This improves power efficiency since only those sections of the stator coil assembly adjacent to the armature allow voltage to be applied and switched.

Claims (8)

A first magnet assembly, a second magnet assembly, wherein the polarity of one of the assemblies changes in response to electrical control signals to cause relative movement between the first and second assemblies along an axis of relative movement In the actuator, One of the assemblies 12 is provided with a pin 14 extending transversely to the axis of relative movement, the other of which is arranged parallel to the axis of relative movement and arranged to receive the pin 14. Electromagnetic actuator, characterized in that a slot (15) is provided. 2. The actuator of claim 1, wherein the second assembly is in the shape of a cylinder arranged to house the first assembly. 3. The actuator according to claim 2, wherein the second assembly consists of a plurality of permanent magnet sections each having pole pieces (24b). 4. The actuator according to claim 3, wherein the pole pieces (24b) taper toward the outer circumference of the assembly. 5. A sliding seal (24) according to claim 2, 3 or 4, characterized in that the end of the cylinder is sealed and the slot (15) is provided with a sliding seal (24) to provide clamping for moving the first assembly in the second assembly. Actuator. 6. The actuator of any one of claims 2 to 5, wherein the second assembly comprises a plurality of coils wound to create a channel to receive the pins of the first assembly. 7. The actuator of claim 6, wherein the coils are wound in pairs in the shape of eight. An assembly according to any one of the preceding claims.