JPS6338949B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to electric machines, and more particularly,
Regarding linear electric motors.

TECHNICAL BACKGROUND Linear electric motors are well known and used in various industrial fields and transportation. Among the main advantages of such motors are the virtually complete elimination of mechanical, hydraulic, and similar intermediate devices for converting rotary movement into deformable separate movements from electrical drive systems. The point of removal is attracting attention. Such an arrangement results in an overall increase in the drive reliability and allows the full utilization of the potential of current control circuits, which cannot be achieved with the modern production of such converters. This is not possible at a technical level.

However, professionals engaged in the development of linear electric motors, especially those utilizing the coupling principle of armature and excitation windings, are faced with the problem of the increasing use of these active materials. are doing.

Linear motors known in the art (USSR Inventor's Certificate No. 192895, Int, Cl, HO2n,
(published on March 2, 1967), this problem can be solved to some extent. The motor includes a stator with a magnetic core formed by two parallel strips of ferromagnetic material. Each strip includes uniformly alternating protrusions and depressions arranged in a row along the strip. The ferromagnetic strips are arranged such that the convex portion of one strip faces the convex portion of the other strip. The protrusions are designed to give a certain shape to the main magnetic field of the motor, and for this reason will be referred to below as pole-forming protrusions. A movable core is arranged between the aforementioned strips, which core sets the processing tool into operation when the motor is used, for example, in a machine tool. The movable core is also comprised of alternating regions of high and low magnetic permeability.

Each strip of the stator magnetic core is constructed in the form of stacked electrical steel sheets with excitation system permanent magnets arranged between them. These magnets are connected in series in an external excitation circuit, ie the north pole of one magnet is placed oppositely to the south pole of the other magnet.
The magnetomotive forces generated by these magnets are directed in unison with each other and transversely across the movable core. Armature windings are mounted on both magnetic cores of the stator, each winding being divided into two coil groups having an equal number of sections. The number of armature windings is arbitrary.

While the linear electric motor arrangement described above has the obvious advantage of significant copper savings, the current is directed to the active part of the armature winding located opposite the low permeability moving core region. This causes the problem of poor efficiency because it does not contribute to the generation of traction force for the flowing object.

Moreover, rotary and linear step motors are characterized by significant counteracting electromagnetic forces on which they are based. However, the presence of such forces has a negative impact on metalworking production processes, for example in the low speed region. This characteristic is typically manifested when DC or AC linear electric motors have a pronounced polar structure along the machine stroke, and the main magnetic field is This becomes evident when there is a longitudinal short in the line.

DISCLOSURE OF THE INVENTION The present invention provides a linear electric motor of a design that ensures increased uniformity of the traction force and thus uniformity of the moving core motion, especially in the low speed range, due to the elimination of counteracting electromagnetic forces. It is based on the purpose of providing.

This objective is achieved in the following way:
The stator magnetic core is made of two strips made of ferromagnetic material, each with multiple rows in the height direction of which uneven parts are formed alternately in the length direction, and high magnetic permeability due to the low magnetic permeability region of the air gap. The region is divided into a plurality of upper and lower parts, and has a movable core disposed between the strips of the stator magnetic core, an excitation winding, and an equal number of turns on both sides of the movable core facing the stator magnetic core. In a linear electric motor consisting of an armature winding arranged in such a manner that the number of rows in which the irregularities of the stator strips are formed alternately in the longitudinal direction is equal to the number of upper and lower sections of the high magnetic permeability region of the movable core. In addition to the number of rows, convex portions and concave portions are alternately formed on each strip in the height direction, and the concave portion of one strip is arranged opposite to the convex portion of the other strip, and the movable core is A plurality of rows of grooves are provided coaxially in each portion of the divided high magnetic permeability region on both active sides facing the stator strips and in a direction perpendicular to the direction of motion of the movable core, so that the armature In addition to placing the winding, recesses are provided along the length direction of the stator on the upper and lower surfaces of the central part of the high magnetic permeability region to form an H shape.A recess in which the excitation winding is formed in the central part of the movable core. It generates a main magnetic flux whose closed magnetic path is perpendicular to the opposing upper and lower convex parts 3 on both sides of the stator and passes through high magnetic permeability regions divided into a plurality of upper and lower parts of the movable core. and armature current drive the movable core in a direction perpendicular to the main magnetic flux in the direction of the convex strips on both sides of the stator, and one of the armature windings
The turns are seated in grooves on one active side facing the stator of the movable core such that the distance between the branches is equal to the width of the protrusion of the stator.

It is expedient to divide the movable core into two equal parts and place a separate excitation winding in each part.

The movable core is divided into three parts, the area of the active side of each lateral part is in the same relationship with the area of the convex part of each stator strip, and the motor is arranged in the central part of the movable core. It is advantageous to have one excitation winding.

The above-described configuration of a linear motor allows reactionary electromagnetic forces to be eliminated in the motor by shorting the main magnetic field lines along the electromagnetic traction force generated by the motor. This results in a significantly reduced variation in the main traction force, thereby increasing uniform motor movement. Uniform movement of the motor is especially necessary when the motor operates within a low speed range (finishing metal working processes, precision positioning).

BEST MODE FOR CARRYING OUT THE INVENTION The linear electric motor of the present invention has a stator in which the stator magnetic core is formed by two equidistant strips of ferromagnetic material. The surfaces of these strips face each other and are provided with uniformly alternating protrusions and depressions of equal width. A movable core with an armature winding and an excitation winding is located between the stator magnetic core strips. The armature windings are configured such that the electromagnetic forces generated by the active surfaces of the armature are equal.

According to one embodiment of the invention shown in FIG. 1, the ferromagnetic bodies 1, 2 of the stator magnetic core have a convex portion 3 and a concave portion 4 ( (Fig. 2). The movable core 5 is divided along the stator into two equal parts 6, 7.

Grooves 8 for arranging armature windings are provided on both sides facing the stator in a plane perpendicular to the moving direction F of the movable core.
Equipped with To facilitate understanding of the figures, groove 8 is only shown in FIG. 1. Both parts of the core 6,
The grooves 8 in 7 are arranged in a plurality of rows along the length of the stator on each active side, with the respective grooves in each core being colinear, i.e. coaxial. The armature windings 9 are placed in sections in the grooves 8 such that each is common to one active side of the core.

For example, in the example shown in FIG. 1, eight grooves are formed on each side of the core facing the stator, and four windings are arranged on each side. Here, the distance between the branches of one section (that is, one turn) of the winding is set equal to the width 3 of the protrusion of the stator, as shown by the broken line in FIG.

In order to arrange the excitation winding on the core, each part thereof is provided with a longitudinal groove 11 giving each core part an H-shaped shape.

The configuration of the movable core determines the number and mutual position of the protrusions 3 forming the magnetic poles. In this embodiment of the invention, the ferromagnetic bodies 1 and 2 have a strip in which a number of rows of concave and convex portions equal to the number of sections of the movable core are formed in the length direction. The portions are arranged alternately, and the protrusions in one row are arranged to face the recesses in the other row. Each row of protrusions 3 is located at the level of a corresponding portion 6, 7 of the core. Furthermore, an important feature of the motor of the present invention is that the convex portion of one strip is opposed to the concave portion of the other strip. As shown in Figure 3, the height of one convex part is
The length of the active conductor of the armature winding 9 of each core 6, 7 lδ
It should be noted that the selection is made equal to .
The distance measured along the height between both rows of convex parts 3,
and the thickness of each convexity is determined from the isolation flux tolerance and is made equal to 10-15δ according to known rules, where δ is the distance between the moving core active plane and the pole-forming convex surface. This is the size of the nonmagnetic air gap on one side.

The parts 6, 7 of the movable core are arranged one above the other without displacement, the distance between them also being equal to h.
In this example, the movable core is divided into two parts: the gap between them is a region with low magnetic permeability, and the core region around which the armature winding and excitation winding are wound is a region with high magnetic permeability. , and high magnetic permeability regions and low magnetic permeability regions are arranged alternately. The division of the armature winding 9 is common to both parts 6, 7 of the moving core, which results in a reduction in copper consumption compared to winding the armature winding separately for each part. .

Figure 3 is a diagram along the line - in Figure 2,
The arrangement of the sections 12 of the armature winding 9 in the magnetic field of the excitation winding 10 is schematically shown. The magnetic flux φ ₀ is
It passes perpendicularly through the upper part of the section 12 (opposite the protrusion), passes obliquely through the lower part of the strip 1 and enters the lower part 7 of the movable core (opposite the protrusion) in a perpendicular direction.

That is, as shown by the broken line in FIG. 1, the direction of the main magnetic flux is perpendicular to the protrusions formed on the strips of the stator, and is perpendicular to the two high permeability regions of the movable core. It is formed in a direction with a certain angle. Then, the main magnetic flux is concentrated on the convex portion in proportion to the overlapping area between the two high magnetic permeability regions of the movable core and the convex portion of the strip, and as the movable core moves, the magnetic flux of each section of the armature winding 9 Changes in coupling occur continuously from zero to a maximum value.

In contrast to the conventional arrangement, in _FIG . Same but half of main magnetic flux φ ₀
It turns out that it is possible to obtain the magnetomotive force of this division with the magnitude of . This makes it possible to reduce the consumption of magnetic material in the motor.

The linear electric motor according to the embodiment described above operates as follows.

Current across the armature winding 9 is provided by using an electromechanical or semiconductor commutator controlled by a position pickup (FIG. 1).
The excitation winding 10 is connected so as to generate a main magnetic flux φ ₀ that is closed in a plane perpendicular to the direction of movement F of the core (dashed line in FIG. 2). The interaction between the armature winding current and the main magnetic flux φ ₀ generates the traction force of the motor, and under this action the core begins to be displaced in the positive direction. The electromechanical or semiconductor commutator switches the direction of the current in the armature winding 9 during the movement of the moving core, and in the conductor located in the area of the ferromagnetic convexes 3 of the upper row, the dielectric When moving in the same direction, the current maintains one direction, while in the conductors located in the region of the protrusions 3 of the lower row the direction is opposite. Reversing the motor is accomplished using conventional methods used for DC motors.

According to another embodiment of the invention shown in FIG. 4, the movable core is divided into three sections 13-15 along the height of the core by a non-magnetic air gap along the stator. Central part 14 and parts 1 on both sides
3 and 15 are provided with two armature windings 9. As can be seen, one winding 9 is common to one active side of the moving core and the other winding 9 is common to the other active side of the core. The height of the central part 14 of the core is twice the height of the lateral parts 13,15. The armature winding 9 is constructed like any conventional winding of a linear DC motor and is connected to a semiconductor or electromechanical commutator which is controlled as a position pickup. The only limitation is that the active conductors of the several sections of each of these windings must be spaced apart from each other by a distance equal to the motor pole pitch.

This configuration of the moving core also determines the design of the stator's magnetic core. As in the previous embodiment, these magnetic cores are two ferromagnetic strips 1, 2 with pole-forming ridges. However, these protrusions 16-18 are arranged with recesses 19 arranged alternately in three rows along the height and opposite the corresponding parts 13-15 of the movable core.
The longitudinal width of 18, like that of the recess, is again equal to the motor pole pitch, and the height corresponds to the height of the oppositely disposed portions of the movable core.
Therefore, the area of each convex portion 16, 18 is equal to half the area of convex portion 17, and the remaining dimensions of the pole-forming convex portions and the dimensions of the air gap are selected as described above.

It should be noted that the end faces of all three parts of the core are clamped by non-ferromagnetic jumpers (not shown) to ensure the rigidity of the moving core.

The excitation winding 20 surrounds the central part 14 of the movable core and is placed in a longitudinal groove 21 as in the previous embodiment. This winding generates a magnetic flux that closes as indicated by the dashed line in this figure.

Although a motor constructed according to the embodiments described above operates largely as described above, the following considerations must be taken into account.

The excitation winding 20 generates a magnetic flux φ ₀ indicated by the dashed line. The commutator, which is controlled as a function of the relative position of the moving core with respect to the stator, establishes the same direction of current in the armature winding conductors at positions opposite the center row ridges 17 forming the eponymous magnetic poles.

Since the width of the armature winding section is equal to the motor pole pitch, conductors with opposing current directions are located opposite poles of opposite polarity. Therefore, the armature winding 9
The traction forces affecting the active side of are directed to the same side. A comparison of the short-circuit path of the magnetic flux in the example motor under consideration with that in the one described above shows that the thickness of the ferromagnetic strip can be reduced by a factor of two if the magnetic flux is the same. be.

The increase in motor dimensions for the embodiment under consideration is slight in terms of height, amounting to 10-15 times that of the non-magnetic air gap. The volume of the excitation winding 20 does not exceed the total volume of the excitation windings in the motors of the previously described embodiments and is somewhat reduced due to the increased length of the magnetic field lines.

According to the research carried out by the inventors, the steel consumption of the linear motor of the present invention is approximately equal to that in the construction of the prior art using the principle of short-circuiting the main magnetic field lines, similar to rotating DC electric motors. It has been demonstrated that the reduction in energy consumption is less than one-sixth. These investigations show that reaction forces are minimized due to the fact that uniform linear displacement rates, on the order of a few mm per minute in typical examples, are obtained.

Industrial Applicability The invention can be used in electric drives intended for reciprocating and linear displacement of industrial mechanisms. The invention is suitable for electric drives designed for example in the field of machine tool technology, transportation and for industrial robots and manipulators when wide range speed control is required with relatively large displacements of work elements. , can show the greatest advantage.

[Brief explanation of the drawing]

The invention will be explained in more detail with respect to embodiments thereof with reference to the accompanying drawings, in which FIG. 1 shows a structural diagram of the linear electric motor of the invention, and FIG. , FIG. 3 shows a magnetic core of one of the stators of the linear electric motor of the invention in a view along the lines of FIG. 2, and FIG. 4 shows a structural diagram of another embodiment of the motor of the invention, FIG. 5 shows a view along the line of FIG. 4, and FIG. A top view is shown.

Claims (1)

[Scope of Claims] 1. A stator magnetic core comprising two strips made of ferromagnetic material, each having a plurality of rows in the height direction in which concave and convex portions are alternately formed in the length direction; The high magnetic permeability area is divided into a plurality of upper and lower parts according to the magnetic permeability area, and the high magnetic permeability area is divided into a plurality of upper and lower parts, and is divided into a movable core placed between the strips of the stator magnetic core, an excitation winding, and a high permeability area on both sides of the movable core facing the stator magnetic core. In a linear electric motor consisting of an armature winding arranged with an equal number of turns, the irregularities of the stator strips alternate in the number of rows formed in the length direction in the high magnetic permeability regions of the moving core. The number of rows is equal to the number of upper and lower sections of the strip, and convex portions and concave portions are formed alternately on each strip in the height direction, so that the convex portion of one strip is opposed to the concave portion of the other strip. The movable core 5 is arranged in each part of the high magnetic permeability region divided into a plurality of sections, and a plurality of movable cores 5 are arranged coaxially in a direction perpendicular to the direction of motion of the movable core on both active sides facing the stator strips. Rows of grooves 8 are provided to place armature windings 9, and recesses 11 are provided along the length direction of the stator on the upper and lower surfaces of the central portion of the high permeability region to form an H-shape for excitation. The winding 10 is arranged in a recess 11 formed in the center of the movable core, and a high-transparent wire is arranged in a recess 11 formed in the center of the movable core, and is perpendicular to the opposing upper and lower convex portions 3 on both sides of the stators 1 and 2, and is divided into a plurality of sections above and below the movable core. A main magnetic flux whose path passing through the magnetic region is a closed magnetic path is generated, and the main magnetic flux and armature current drive the movable core in a direction F perpendicular to the main magnetic flux in the direction of the strip convex portions on both sides of the stator. It is ensured that the child winding 9 is placed in the groove 8 on one active side facing the stator of the movable core so that the distance between the branches of one turn is equal to the width of the protrusion of the stator. Features a linear electric motor. 2. A linear electric motor according to claim 1, characterized in that the movable core is divided into two equal parts 6, 7, and a separate excitation winding 10 is placed on each part. . 3. The movable core is divided into three parts 13 to 15 such that the area of the active side of each side part 13, 15 is equal to half the area of the active side of the central part, and the stator The areas of the protrusions 16 to 18 of each strip are in the same relationship, and the motor comprises an excitation winding 10 arranged on the central part 14 of the movable core. A linear electric motor as described in paragraph 1. 4 The excitation winding 10 is arranged so as to generate a main magnetic flux that is closed within a plane perpendicular to the moving direction F of the movable core. electric motor. 5. The main magnetic flux generated by the excitation winding is configured to concentrate on the convex portion in proportion to the area where the convex portion of the strip and the high magnetic permeability region of the movable core overlap. A linear electric motor according to claim 1.