JPH09182408A - Linear motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the multipolar multiphase linear motor, which has large thrust and can achieve space saving and unitization, by providing a movable part, which is protruding to the outside through the opening parts of sleeves. SOLUTION: A plurality of magnetic poles for a magnetic field system are formed in the axial direction of the outer surface of a magnetic circuit part 15 for a magnetic field system. For a stator 20, sleeves 3 and 4 are arranged so as to face each other through the magnetic circuit part 15 for the magnetic field system 15 and a magnetic gap 9. In the magnetic gap 9, coils 7a-7c generating thrust are provided. Furthermore, a movable part 30 is arranged along the axial direction of the magnetic circuit part 15 for the magnetic field system freely movably and made to protrude to the outside through the opening parts of the sleeves 3 and 4. Thus, the linear motor having the large thrust can be constituted. Furthermore, space saving (compactification) and the unitization can be achieved. In addition, the linear motor having the excellent heat radiating property can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substantially cylindrical multi-pole multi-phase linear motor capable of obtaining a large thrust, and further,
Space saving and unitization are possible,
The present invention relates to a linear motor having good heat dissipation.

[Prior art]

A linear motor can drive an object to be controlled linearly or arcuately with a large thrust force, and can be set with a highly accurate step position in combination with a position detecting means such as an encoder. Transport device, X
-It is widely used in two-way drive devices such as Y tables, position control devices for precision parts, and the like.

FIG. 8 shows a conventional linear motor (Japanese Patent Laid-Open No. 7-1.
No. 70710), and FIG. 9 is a lateral cross-sectional view of the main part of FIG. 8 and 9, the field magnet 122 is arranged on the cylindrical inner surface of the casing 121, the opening 121a formed along the axial direction of the casing 121, the end plates 121b at both ends, and the end plate 121b. Field magnet 12
2, the center center yoke 123, and the opening / closing lid 12 that can be opened / closed in a round hole opened for attaching / detaching the mover 124.
1c and.

The field magnet 122 is combined with a plurality of divided magnets and is integrally arranged on the cylindrical inner surface of the casing 121. In the combined state, the field magnet 122 is aligned with the opening 121a of the casing 121. The slit 122a is formed. The center yoke 123 is coaxially arranged at the centers of the casing 121 and the field magnet 122 to serve also as the yoke, and is formed in a columnar shape. Then, based on the above configuration, a driving force is generated between the movable element 124 and the field magnet 122 by supplying power to the driving coil 124b. The drive force of the mover 124 is transmitted from the opening 121a and the slit 122a to the component support plate 128 via the drive arm 126, and the control target component and the like mounted on the component support plate 128 are given a thrust force. Move along the axis.

FIG. 10 shows another example of a conventional linear motor (see Japanese Patent Laid-Open No. 7-194085). In the cylindrical linear DC motor of FIG. 10, the stator 221 includes a first yoke 223 having a cylindrical shape, and a first permanent magnet 2 fixed to the outer cylindrical surface of the first yoke 223 in a coaxial cylindrical shape.
26 and a second yoke 22 having a cylindrical shape, which is arranged on the outer cylindrical surface of the first permanent magnet 226 in a coaxial cylindrical shape at a predetermined distance and has an opening (not shown) formed in the axial direction.
4 and a pair of disk-shaped third yokes 225a, 225b that are fixed to both ends of the inner cylindrical surface of the second yoke 224 and both ends of the outer cylindrical surface of the first yoke 223. Is composed of. The mover 222 is the stator 2
The outer cylindrical surface of the first permanent magnet 226 and the inner cylindrical surface of the second yoke 224, which form part 21, respectively, have a structure capable of smoothly moving in the axial direction with a predetermined gap.
The coil 228 has a cylindrical shape, and the second permanent magnet 230 has a cylindrical shape and is electrically insulated and fixed to the outer cylindrical surface of the coil 228. The thrust generated in the mover 222 is transmitted to the outside through the opening of the second yoke 224.

FIG. 11 shows an example of an optical scanning device in a conventional electrophotographic copying machine using a linear motor (Japanese Unexamined Patent Publication No. Hei 2 (1999) -211).
No. 151,259). In FIG. 11, a linear motor 310 is a mover 312, 3 having drive coils arranged on both sides of the drum projection optical mechanism 330.
12 and stators 311 on both sides, which are provided to face each other and are provided upright, and each of which includes a field permanent magnet and a yoke.
311 and the guide members 35 on both sides.
The movement of the movers 312 and 312 is restricted by 0, 350, and the drum projection optical mechanism 330 mounted on the member connecting the movers is moved from the initial position in the document scanning direction and then in the return direction (the document It is moved in a predetermined speed pattern such as moving in the direction opposite to the scanning direction) and returning to the initial position. The linear motor 320 also has a configuration similar to that of the linear motor 310, and includes the stators 311 and 311 on both sides and the guide members 350 and 350.
, And the original scanning optical mechanism 340 mounted on a member that connects the movers 322 and 322 on both sides to each other.
Is moved along the guide member 350 with a predetermined speed pattern. As described above, the drum projection optical mechanism 330 and the document scanning optical mechanism 340 are each scanned at a predetermined speed pattern, and the optical scanning device in an electrophotographic copying machine using a so-called conventional square linear motor is used. I am configuring.

[0007]

However, the conventional linear motors described above have the problems that it is difficult to increase the thrust, save the space (downsize), and unitize them, as will be described later. First, in the linear motor configured as shown in FIG. 9, the magnetic field strength of the magnetic gap 130 formed between the center yoke 123 and the field magnet 122 is limited by the cross-sectional area (S1) of the center yoke 123, and the linear motor is linear. That is, it is impossible to generate a thrust large enough for practical use as a motor. In recent years, there has been an increasing need for miniaturization of linear motors, and when the configurations of FIGS. 8 and 9 are adopted, the outer diameter dimension of the center yoke 123 is limited to a small dimension from the viewpoint of miniaturization, and the field magnet 122 It is difficult to obtain a sufficient cross-sectional area for the passage of the generated magnetic flux. Usually, the cross-sectional area S1 of the center yoke 123 and the cross-sectional area S2 of the field magnet 122 are S
It is preferable that 1 ≧ S2 in order to prevent the magnetic saturation of the center yoke 123 and form the magnetic air gap 130 having a strong magnetic field strength. However, in FIG. 8 and FIG. Inevitably, a configuration in which S1 <S2 is adopted, and the magnetic field strength of the magnetic air gap 130 is limited, which limits the increase in thrust of the linear motor. Further, since the field magnet 122 has a single-pole structure in which the magnetic poles on the inner peripheral side are uniformly S poles and the outer peripheral side is uniformly N poles, a multi-pole configuration that is often used in a general rectangular linear motor. Between the field magnet and the ferromagnetic yoke (for example, a plurality of permanent magnets arranged in parallel so that the polarities of the adjacent magnetic poles are different and the magnetic pole surfaces are aligned, are provided through the magnetic gap. It is difficult to form a closed magnetic path in a short range in each region where the magnetic pole changes, such as when the magnetic poles are arranged parallel to each other. Therefore, as compared with the case where the multi-pole field magnet is used, a large amount of leakage flux is easily generated, and the magnetic air gap 130 having a strong magnetic field strength cannot be formed (that is, the linear motor cannot have a large thrust). It also has the problem.

Next, in the linear motor of FIG. 10, the first permanent magnet 226 and the second permanent magnet 230 have a coil 228.
Coil movable linear direct current motor having the same configuration of the single pole type field magnet as in FIG. 9 described above, which forms a magnetic field in a radial direction that intersects with each other and has opposite polarities. Is. Therefore, although there is a problem of leakage flux as in the case of FIG. 9, in order to suppress the leakage flux, the first yoke 223, the first permanent magnet 226, the second permanent magnet 230, and the second yoke 224 are included. However, there is a problem in that an inexpensive linear motor cannot be manufactured because the linear motor becomes large and the amount of expensive permanent magnets increases because of the increase in size of the linear motor. . Further, since the field magnet is a single pole type, it is difficult to increase the thrust of the linear motor.

Next, in the rectangular linear motor mounted in the conventional optical scanning device for a copying machine shown in FIG. 11, a stator 311 composed of a large-sized field permanent magnet and a yoke is provided as a mover 312. Since the stroke of 322 is fixedly provided on the side surface of the frame, the space occupied by the linear motors 310 and 320 in the optical scanning device is very large, and the optical scanning device for a copying machine equipped with the linear motor is downsized. There is a problem that you can not. In FIG. 11, if the linear motors 310 and 320 including the stator 311 are simply downsized, the magnetic field strength of the magnetic gap required for driving the linear motor is significantly reduced, and the linear motors 310 and 320 are driven with a large thrust. It is hard to make them do it. Further, in the above optical scanning device, since the linear motor portion is not unitized, there is a problem that the linear motor cannot be easily incorporated or replaced.

The present invention is a substantially cylindrical multi-pole multi-phase type linear motor that solves the above-mentioned conventional problems and can obtain a large thrust, and can further save space and be unitized. An object of the present invention is to provide a linear motor having good heat dissipation.

[0011]

In order to solve the above-mentioned problems, in the first invention of the present invention, a field magnetic circuit portion in which a plurality of field magnetic poles are formed in the axial direction of the peripheral surface thereof. A stator provided with a sleeve arranged to face the magnetic circuit for the field via a magnetic gap, and a coil arranged in the magnetic gap to generate thrust, and the magnetic field A linear motor having a structure in which it is arranged so as to be movable along the axial direction of the circuit part and has a mover protruding outward through the opening of the sleeve is adopted. In the second invention of the present invention, the hollow first sleeve, the field permanent magnet in which the magnetic poles are arranged to face each other in the axial direction in the first sleeve, and the magnetic poles of the permanent magnets are A stator provided with a yoke arranged in a facing gap; and a hollow second sleeve facing the first sleeve via a magnetic gap and having an opening formed in the axial direction thereof; A mover provided with a coil holder that is slidably fitted on the sleeve and slidable and projects outward through the opening of the second sleeve, and a polyphase coil arranged in the coil holder. The linear motor with the configuration of is adopted. According to the first and second inventions described above, a magnetic gap having a strong magnetic field strength can be formed even if the linear motor is downsized, and thus a linear motor having a large thrust can be manufactured.

Further, according to the present invention, by disposing the linear bearing on the mover, the mover can be arranged so as to be able to slide smoothly along the axial direction of the field magnetic circuit section.
In the second aspect of the invention, by disposing the cooling fins adjacent to the second sleeve, the heat generated mainly by energizing the multiphase coils is transferred to the cooling fins to increase the temperature of the multiphase coils. Can be suppressed. Further, in the above-mentioned present invention, a large thrust force can be generated in the moving coil type linear motor of the present invention by supplying a 3-phase or 2-phase drive current (preferably a sinusoidal drive current) to the coil. Generally, in a multi-pole / multi-phase linear motor in which the field permanent magnet has multiple poles and the driving current is supplied to the multi-phase coil, the power factor decreases as the number of phases increases, so the input current Need to increase. Therefore, it is preferable to adopt the three-phase or two-phase energization method, and the three-phase energization method is particularly preferable in practical use.

Further, the linear motor of the present invention can be used in an optical scanning device (for example, a copying machine).
According to this configuration, the space saving, which is a feature of the linear motor of the present invention, can be used to reduce the size of the optical scanning device, and an optical scanning device with a large thrust can be configured. Further, since the linear motor of the present invention has a compact structure in which the stator and most of the mover are embedded in the second sleeve, it has an excellent feature that the linear motor incorporated in an optical scanning device can be unitized. Have. Therefore, for example, even if it is necessary to replace the linear motor of the present invention incorporated in the optical scanning device, the replacement work can be efficiently performed in the unitized linear motor unit, so that the replacement work is greatly simplified. There is an advantage that you can.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view of a main portion in the axial direction of a linear motor showing an example of an embodiment of the present invention. In FIG. 1, 1 is a solid cylindrical field permanent magnet (for example, N manufactured by Hitachi Metals, Ltd.).
d-Fe-B type anisotropic sintered magnet, HS-37BH and the like. )
And an oxidation resistant Ni plating layer (average film thickness 30
.mu.m) and is magnetized in the axial direction (the magnetizing direction coincides with the magnetic anisotropy direction) to give N and S magnetic poles shown in the figure. Reference numeral 2 is a ferromagnetic yoke (for example, made of SS400), which is formed in a solid cylindrical shape. 3 is a non-magnetic first sleeve (for example, SUS304
Manufacturing etc. In this first sleeve 3, the permanent magnets 1 and the yokes 2 are alternately fixedly attached in the axial direction by using, for example, an epoxy adhesive, and the permanent magnets 1, 1 are arranged in the axial direction. Are arranged so that the same magnetic poles face each other via the yoke 2. Here, the permanent magnet 1 and the yoke 2 are arranged coaxially with the first sleeve 3.
Then, first, in order to arrange the yoke 2 coaxially with the first sleeve 3, the outer diameter dimension of the yoke 2 is arranged so that the outer peripheral surface of the yoke 2 is closely arranged parallel to the inner peripheral surface of the first sleeve 3. And the inner diameter of the first sleeve 3 are adjusted.
Next, in order to coaxially dispose the permanent magnet 1 disposed in contact between the yokes 2 and 2 with respect to the first sleeve 3, each yoke 2
The recesses 13 and 13 for positioning the permanent magnet 1 are formed in the center of both axial end faces of the permanent magnet 1, and the axially opposite end faces of the permanent magnet 1 are sandwiched by the recesses 13 and 13.
Further, a space 17 surrounded by the inner peripheral surface of the first sleeve 3, the end surfaces of the yokes 2, 2 and the outer peripheral surface of the permanent magnet 1 is formed,
The air gap 17 and the non-magnetic first sleeve 3 suppress the leakage magnetic flux f2 as shown by the dotted line, and most of the magnetic flux generated from the permanent magnet 1 is only the effective magnetic flux f1 that contributes to the formation of the magnetic air gap 9, The magnetic gap 9 having a strong magnetic field strength can be formed. Further, as described above, the permanent magnet 1 and the yoke 2
Since the first sleeve 3 and the first sleeve 3 are coaxially arranged, it is easy to form the magnetic gap 9 formed on the outer peripheral side of the first sleeve 3 as a magnetic flux density distribution space that is symmetrical in the radial direction thereof, and it is possible to control the linear motor. Highly preferred. Therefore, the first
According to the field magnetic circuit portion 15 configured by the same magnetic poles of the permanent magnet 1 facing each other in the axial direction in the sleeve 3 with the yoke 2 interposed therebetween, the outer diameter dimension of the second sleeve 4 will be described later. Is 100 mm or less, preferably 50 mm or less, and particularly preferably 30 mm or less, the magnetic field strength of the magnetic air gap 9 formed on the outer peripheral side of the first sleeve 3 can be maintained at a large level. The large thrust force of the motor 33 can be maintained.

In FIG. 1, 6 is a coil holder made of an insulating synthetic resin (for example, made of polyacetal resin), which is slidably arranged on the first sleeve 3 and is slidable. , 6a, 6 projecting to the outer peripheral side through the opening 10 formed along the axial direction of the ferromagnetic second sleeve 4 (for example, SS41).
b is formed. Here, the opening portion 10 has an axial length corresponding to the stroke of the linear motor 33, and the protruding movable element portions 6a and 6b are accurately moved along the axial direction while suppressing pitching, yawing, etc. as much as possible. Has the function of a linear guide for. Therefore, as shown in FIG. 5, which will be described later, the width x of the opening 10 is determined by the thickness t of the protruding portions 6a and 6b and the clearance between the protruding portions 6a and 6b and both edges of the opening 10. It is appropriately determined in consideration of tc. Further, the coil holder 6c is provided with three three-phase coils 7a, 7b, 7c formed by winding a known coil winding whose surface has been subjected to an insulation treatment in a cylindrical shape in the circumferential direction. In addition, the coil holder 6c has a side facing the first sleeve 3 and the coils 7a, 7b, 7c.
At the position corresponding to the center of each winding width w of the three magnetic pole detecting means (for example, Hall elements 11a, 11b, 11c).
etc. ) Are arranged respectively. Here, the coils 7a, 7
The winding widths w of b and 7c are equalized, and the magnetic pole pitch λ of the field magnetic circuit 15 (the concave portion 1 of the yoke 2 is
3, the thickness in the axial direction of ty is ty, and the permanent magnet 1 is
Is tm = 2 (ty +
tm). That is, λ corresponds to the width of the two magnetic poles N and S in the axial direction on the outer peripheral surface of the first sleeve 3. ) With respect to each other by 120 ° in electrical angle, the thrust force is applied to the linear motor 33 by energizing the phase-controlled three-phase alternating current. In addition, the hall elements 11a, 11b, 11c
Is a yoke 2 arranged between permanent magnets 1 and 1 having the same magnetic pole
The magnetic poles N and S formed on the outer peripheral surface side of the first sleeve 3 are detected by reflecting the magnetic poles N and S of FIG. The direction is switched or selected. Further, the linear bearings 12, 12 are provided at both ends of the coil holder 6 on the sliding surface side.
Is provided to enable smooth sliding. Based on the above configuration, in the magnetic gap 9, the three-phase coils 7a, 7a
When a three-phase sinusoidal current is supplied from a drive circuit (not shown) to the drive circuits b and 7c via the power supply lines 14, the coils 7a, 7b and 7c and the hall elements 11a and 11 are supplied.
The mover 30 including b and 11c, the bearings 12 and 12, and the coil holder 6 generates a thrust force along the axial direction of the opening 10 formed in the second sleeve 4 according to Fleming's left-hand rule. Move in the axial direction. Further, the second sleeve 4 is coaxially arranged with the first sleeve 3, and the magnetic gap 9
Are arranged so that their radial thicknesses are equal. Further, as described above, in the present embodiment, since the second sleeve 4 is made of a ferromagnetic material, the effective magnetic flux f1 tends to flow toward the inner peripheral surface side of the second sleeve 4, resulting in a stronger magnetic field strength. The magnetic gap 9 can be formed. The three-phase coils 7a, 7b, 7c are not limited to three, but four or more (preferably 3n, n = 1, 2, 3, ... ).
In this case, it goes without saying that the coils that are electrically in phase are commonly connected by a known connection method. Further, instead of the above-mentioned three-phase energization method, a two-phase energization method can be adopted. In this case, the number of Hall elements is two, and the number of coils is preferably 2n (a positive integer such as n = 1, 2, 3, etc.), but may be any number of 3 or more, and the above three phases may be used. Similar to the case of, the coils having the same phase are commonly connected.

Further, in FIG. 1, both axial ends of the first sleeve 3 and the second sleeve 4 are coaxially supported and fixed to a well-known end bracket 8 (for example, made of polyacetal resin) made of a non-magnetic material. In addition, the protruding portions 8a formed at both axial end portions of the end bracket 8
Is fitted and fixed in a hole provided in a predetermined fixing portion (not shown) (for example, a fixing frame of a linear motor). The end bracket 8 has a function of adjusting the thickness dimension of the magnetic gap 9 in the radial direction. Further, a cooling fin 5 made of a non-magnetic heat conductor is provided on the outer peripheral side of the second sleeve 4.
(For example, the surface is made of an aluminum alloy whose surface is anodized.). The cooling fins 5 may be provided over the entire surface of the second sleeve 4, or may be configured to partially cover the second sleeve 4, so that the linear motor 33 can be downsized and the cooling fins 5 can be formed. It can be appropriately formed in consideration of heat dissipation. Based on the above configuration, the stator 20 including the permanent magnet 1, the yoke 2, the first sleeve 3, the second sleeve 4, the cooling fins 5, and the end bracket 8 is configured.

Next, FIG. 2 shows the linear motor 3 of FIG.
3 is a cross-sectional view of an essential part in the axial direction for explaining an example of the optimum dimensional relationship between the magnetic pole pitch λ for obtaining a large thrust and the width w of each three-phase coil, and the same reference numerals as in FIG. It shows the constituent parts. FIG. 2 shows that the coil holder 6 has two 3-phase winding type coils 7a, 7b and 7c, each having a total of 6 coils.
In this example, the coil widths w = λ / 6 are arranged adjacent to each other along the axial direction. The Hall elements 11a, 11b, 11c are sequentially displaced in the axial direction by 120 ° in electrical angle, and the coils 7a, 7b, 7c
It is arranged corresponding to each of c. Then, a large thrust force is applied to the linear motor 33 by supplying a phase-controlled three-phase alternating current to each coil.

Next, FIG. 3 shows a cross-sectional view of a main portion in the axial direction of a linear motor showing another example of the embodiment of the present invention. In FIG. 3, the same reference numerals as those in FIG. 1 represent the same components as those in FIG. In FIG. 3, the coil holder 6 ′ is formed of a known synthetic resin (for example, oil-impregnated polyacetal resin, etc.) that has an insulating property and is highly self-lubricating. Also, the permanent magnet for field 1 '
(For example, Cu having an average film thickness of 4 μm is formed on the surface of the permanent magnet 1 ′.
It has a multi-layered oxidation resistant coating in which plating is formed, Ni plating having an average film thickness of 50 μm is formed thereon, and an electrodeposited epoxy coat layer having an average film thickness of 30 μm is further formed thereon. ) And a ferromagnetic yoke 2 '(eg SS41
Made. ) Is formed in a ring shape having a through hole 24 having the same inner diameter. Further, the support rod 22 is coaxially arranged at the axial center position in the first sleeve 3. The support rod 22 is a known non-magnetic material (for example, SUS304) in order to prevent a short circuit of magnetic flux between the permanent magnet 1'and the yoke 2 '.
etc. ) Is preferable. Both end portions in the axial direction of the support rod 22 are supported and fixed to the end bracket 8. Further, the permanent magnets 1'and the through holes 24 of the yoke 2'are alternately passed through the support rods 22 and stacked in the axial direction thereof to form the field magnetic circuit 15. The permanent magnet 1 ', the yoke 2', and the support rod 22 are fixed to each other with, for example, an epoxy adhesive. Further, the outer peripheral portion of the support rod 22 and the through holes 24 of the permanent magnet 1'and the yoke 2 '.
The permanent magnet 1 ′, the yoke 2 ′, and the support rod 22 are coaxially arranged with respect to the first sleeve 3 by engaging with the first sleeve 3. According to the configuration of the linear motor 33 'of FIG. 3, since the linear bearing 12 of FIG. 1 can be omitted, there is an advantage that the linear motor of the present invention can be manufactured at a lower cost.

Next, FIG. 4 shows the linear motor 3 of FIG.
3'is an axial main part cross-sectional view illustrating an example of the optimum dimensional relationship between the magnetic pole pitch λ and the width w of the three-phase coil for obtaining a large thrust, and the same reference numerals as in FIG. 3 denote the same parts. It shows the constituent parts. FIG. 4 shows that the coil holder 6'includes three 3-phase winding type coils 7a, 7b and 7c, each having a total of 3 coils.
This is an example in which the coil widths w = λ / 6 are arranged along the axial direction as shown in the figure. Further, the Hall elements 11a, 11b, 11c are arranged corresponding to the coils 7a, 7b, 7c by sequentially shifting their positions by 60 ° in terms of electrical angle in the axial direction. A large thrust force is applied to the linear motor 33 'by supplying a phase-controlled three-phase alternating current to each of the coils. Here, in FIG. 2 described above, for example, the arrangement position of each coil may be slightly deviated from the arrangement pitch λ / 6, reflecting the variation of each coil such as mutual inductance, and therefore the adjacent arrangement is The total axial length of the six coils (the leftmost coil 7 in FIG.
Distance from the left end of a to the right end of the rightmost coil 7c)
May be slightly larger than the magnetic pole pitch λ, but is set to substantially λ in terms of the driving principle. Also in FIG. 4 above, for the same reason, the total axial length of the three coils is substantially λ.
/ 2. Further, in place of the winding type coils 7a, 7b, 7c, 7a, 7b, 7c shown in FIG. 2, a known three-phase flat coil (for example, see Japanese Patent Laid-Open No. 62-25861) is used. 2 is formed into a thin cylindrical shape and arranged as the coils 7a, 7b, 7c, 7a, 7b, 7c of FIG. 2, the radial thickness of the magnetic gap 9 can be made thinner, and the linear motor of the present invention can be further improved. It is very preferable because it can produce a large thrust. In addition, it goes without saying that in FIG. 3 and FIG. 4 described above, for example, the first sleeve 3 may be omitted to configure the field magnetic circuit unit 15. Further, since the coils 7a, 7b, 7c are formed in a hollow cylindrical shape having no notch, the number of interlinking portions is larger than in the case of having the notch, which is extremely advantageous for increasing the thrust of the linear motor. However, the present invention is not limited to this, and it goes without saying that the coils 7a, 7b, 7c can be configured to have notches.

FIG. 5 is a sectional view taken along line AA of the linear motor 33 'shown in FIG. In FIG. 5, the fins 5 for cooling are alternately provided with convex portions 5a and concave portions 5b in order to improve heat dissipation.

FIG. 6 is a diagram showing an example of an application device using the linear motor of the present invention, and the parts having the same reference numerals as those in the above-mentioned embodiment represent the same constituent parts. FIG.
2, the structure of the stator 20 of the linear motor 16 is shown in FIG.
Which is similar to that of the first embodiment and includes a permanent magnet 1 and a yoke 2.
A stator 20 including a sleeve 3, a second sleeve 4 coaxially arranged with the first sleeve 3 via a magnetic gap 9 and having an opening 10 formed in the axial direction thereof, and a cooling fin 5 are provided. ing. Here, this linear motor 16
2 is different from that of FIG. 2 in that two movers 30 of the linear motor 33 of FIG. 2 are arranged on the first sleeve 3 in an externally fitted state and slidably arranged. Therefore, as shown in FIG. 6, the protruding portions 6a and 6b of the coil holder 6 are
As a set, the projecting portions of the two sets are projected from the opening 10 of the second sleeve 4, and the connecting members 26 and 27 connected to the respective tips of these projecting portions, and the connecting member 2
Two movers 30 and 30 each having side plates 21a and 21b respectively connected to the other ends of 6 and 27 are provided.
The vicinity of the other ends of the connecting members 26 and 27 is guided by the guide means 23 in the axial direction thereof, that is, the linear motor 1.
6 is supported so as to be movable in parallel to the axial direction of 6. The guide means 23 includes a guide rod 19 arranged parallel to the axial direction of the linear motor 16 and the guide rod 19 thereof.
Bearings 18 and 18 which are slidably engaged with and are integrally disposed on the connecting members 26 and 27, respectively. Further, a substrate 34 which is erected on a fixed portion (not shown) of the applied device of FIG. 6 is arranged parallel to the side plates 21a and 21b along the axial direction of the linear motor 16 with a gap therebetween. This board 34
An encoder scale 35 is provided in parallel to the axial direction of the encoder, and encoder position reading units 36, 36 are provided on the sides of the side plates 21a, 21b facing the scale 35. Based on this configuration,
When the two movers 30, 30 move, the position reading units 36, 36 count the scales of the scale 35 so that each position of the movers 30, 30 can be recognized with high accuracy. Here, the movers 30 and 30 can be moved in the axial direction of the linear motor 16 in different synchronized speed patterns, or can be moved in the axial direction with the same speed pattern. Therefore, a predetermined controlled component, a transport member (not shown), or the like is mounted on each of the two movers 30 and 30, and an application device using the linear motor of the present invention can be configured.

In FIG. 7, the application device shown in FIG. 6 (the outer diameter of the second sleeve 4 of the linear motor 16 is designed to be 30 mm) is mounted on the optical scanning device 100 for moving the optical mechanism of the copying machine. FIG. 7 is a perspective view of an essential part showing an example, and the portions having the same reference numerals as those in FIG. 6 represent the same components as in FIG. 6. In FIG. 7, the end brackets 8a arranged at both ends of the stator 20 of the linear motor 16 are fitted and supported in the through holes provided in the frame 50a of the optical scanning device 100 of the copying machine, and the linear motor 16 is also supported. A pair of coil holder protruding portions 6a protruding from the opening 10 in
An optical mechanism 45 for drum projection is mounted on the connecting member 26 connected to 6b. An original scanning optical mechanism 55 is mounted on the connecting member 27 connected to the other pair of coil holder protruding portions 6a and 6b protruding from the opening 10. Then, the drum projection optical mechanism 45 and the document scanning optical mechanism 55 are each scanned with a predetermined speed pattern to form the optical scanning device 100 of the copying machine using the linear motor of the present invention. The structure of the connecting members 26 and 27 on the side of the frame 50b is the same as that shown in FIG. 6, and is provided with the guide means 23, the side plates 21a and 21b, the substrate 34, the encoder scale 35, the encoder position reading means 36, 36, and the like. Thus, the positioning control with high accuracy is possible. Further, the linear motor 16 includes the frame 50a portion and the connecting member 2
6 and 27, the linear motor 16 is connected to and fixed to the optical scanning device 10.
The so-called linear motor 16 can be handled as a unit which is a set of built-in parts, which can be easily installed or removed from the unit. Further, according to the configuration of FIG. 7, the linear motor 16 of the present invention has the magnetic circuit structure 15 in which the permanent magnet 1 and the yoke 2 are arranged in the first sleeve 3 and which is optimal for space saving, and at the same time, Magnet 1, 1
Since the magnetic poles formed on the yoke 2 by the repulsive magnetic field between the same magnetic poles form a strong magnetic gap 9 in the outer peripheral side space of the first sleeve 3, a large thrust force is exerted even if the outer diameter of the linear motor 16 is reduced. Can be maintained. Therefore, a significant space saving is achieved as compared with the linear motor used in the conventional optical scanning device for a copying machine (for example, FIG. 11), which greatly contributes to downsizing of the linear motor type optical scanning device for a copying machine. To do. Although FIG. 7 shows an example in which the linear motor of the present invention is used in an optical scanning device of a copying machine, the present invention is not limited to this and can be applied to other known optical scanning devices. is there.

In addition, a conventional linear motor (see, for example, FIG. 9)
Or the configuration of FIG. 10) has the same outer diameter dimension as the linear motor of the present invention (corresponding to the outer diameter dimension of the second sleeve 4 in the linear motor of the present invention, and is formed to 30 mm, for example).
In that case, the linear motor of the present invention has a large thrust of about 30% or more as compared with the conventional one.

In FIGS. 1 to 4 described above, an example of a structure is shown in which the repulsive magnetic field formed by arranging the same magnetic poles of the field permanent magnets facing each other is used as the field magnetic circuit section 15. The invention is not limited to this. For example,
In FIG. 2, a publicly known ring magnet (radial anisotropic ring magnet: HS-20BR manufactured by Hitachi Metals, Ltd.) is used in place of the field permanent magnet 1 and the yoke 2, and the outer peripheral surface thereof is used. An elongated body or a plurality of ring magnets arranged in parallel or in close contact with the inner peripheral surface of the first sleeve 3 and having an axial dimension commensurate with the stroke of the linear motor 33 are arranged in the axial direction in the first sleeve 3. The magnetic poles are arranged coaxially and, by using an appropriate magnetizing means, different magnetic poles are alternately formed at equal magnetic pole pitches in the axial direction of the outer peripheral surface of the integrally elongated object or the plurality of ring magnets coaxially arranged. Thus, the magnetic circuit for field can be configured.
Further, for example, in FIG. 4 described above, the field permanent magnet 1 '
Instead of the yoke 2 ′ and the first sleeve 3, a single elongated body or a plurality of the above ring magnets are coaxially arranged around the support rod 22, and the integral long body or a plurality of shafts of the outer peripheral surface. It is also possible to form the magnetic circuit for magnetic field so that different magnetic poles are alternately formed in the same direction at equal magnetic pole pitches and the outer peripheral surface on which the magnetic poles are formed is directly exposed to the magnetic gap 9. As described above, it is needless to say that the magnetic circuit for field of the present invention can be constructed by utilizing the magnetic poles formed on the outer peripheral surface of the ring magnet.

Further, in the above-mentioned present invention, an example in which the first sleeve 3 is formed of a known non-magnetic material and the second sleeve 4 is formed of a known ferromagnetic material has been described, but the present invention is not limited to this. However, the magnetic field strength of the magnetic gap tends to decrease, but for example, the first sleeve 3 may be formed of a known ferromagnetic material and the second sleeve 4 may be formed of a known non-magnetic material. Further, the first and second sleeves may be formed only by a known ferromagnetic material or non-magnetic material. Furthermore, the first and second sleeves may each be composed of a known combination of a ferromagnetic material and a non-magnetic material. Further, in the above-mentioned present invention, the first and second sleeves and the coil are formed in a hollow cylindrical shape, but other shapes (for example, preferably the hollow-shaped angular shape similar to the three parties,
Rectangular shape, irregular shape, etc. ) Is good. Further, the first and second sleeves may be formed by a known fastening (adhesion) means using a plurality of divided parts. Further, in the above-mentioned present invention, the shapes of the permanent magnet and the yoke are the solid cylindrical shape and the ring shape, but it goes without saying that other shapes can be adopted. Further, the dimensions and number of permanent magnets and yokes, the number of movers, and the like can be appropriately determined in the design and manufacturing process. Also,
In the present invention, the case where the number of Hall elements is three or two is described, but the number is not limited,
For example, it is preferable to use it by matching it with a multiple of the phase number of the drive current to be used, and a known magnetic pole detecting means instead of the Hall element may be used. Further, in the above-mentioned present invention, the case of a three-phase or two-phase coil is described, but more multiphase (preferably 3n phase or 2n phase: n = 2, 3, 4, ..., etc. positive integers). Of course, a coil configuration may be used. Further, in the present invention described above, the example in which the cooling fin 5 is arranged on the outer peripheral side of the second sleeve 4 has been described, but it may be arranged on the inner peripheral side thereof. Further, the cooling fins 5 may be arranged at both ends of the first sleeve 3, or the end brackets 8 may be made of the material forming the cooling fins 5.

[0026]

The present invention is a substantially cylindrical multi-pole multi-phase linear motor having the unique features as described above.
The following effects can be achieved. (1) A large thrust linear motor can be constructed. (2) Space saving (miniaturization) is possible. (3) The linear motor can be made into a unit, and, for example, the work of assembling and replacing it in the optical scanning device of the copying machine can be greatly simplified. (4) It is possible to provide a linear motor having good heat dissipation.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an essential part in an axial direction showing an example of a linear motor of the present invention.

FIG. 2 is a diagram illustrating a relationship between a coil width and a magnetic pole pitch in the linear motor of FIG.

FIG. 3 is a sectional view of an essential part in the axial direction showing another example of the linear motor of the present invention.

FIG. 4 is a diagram illustrating a relationship between a coil width and a magnetic pole pitch in the linear motor of FIG.

FIG. 5 is a sectional view taken along line AA of FIG. 3;

FIG. 6 is a diagram showing an example of a linear motor application device of the present invention.

FIG. 7 is a diagram showing an example in which the linear motor of the present invention is installed in an optical scanning device of a copying machine.

FIG. 8 is a perspective view showing a conventional linear motor.

9 is a diagram showing a cross-sectional view of a main part of FIG.

FIG. 10 is a diagram showing a conventional linear motor.

FIG. 11 is a diagram showing an example in which a conventional linear motor is mounted on an optical scanning device of a copying machine.

[Explanation of symbols]

1, 1'permanent magnet, 2,2 'yoke, 3 first sleeve, 4 second sleeve, 5 cooling fins, 6, 6
a, 6b, 6c, 6 ', 6a', 6b ', 6c' coil holder, 7a, 7b, 7c coil, 8, 8a end bracket, 9 magnetic air gap, 10 opening, 11
a, 11b, 11c Hall element, 12 bearings, 13
Yoke recess, 14 feeder, 15 magnetic circuit for field,
17 voids, 18 bearings, 19 guide bars, 20 stators, 21a, 21b side plates, 22 support rods, 23 guide means, 24 through holes, 26, 27 connecting members, 3
0,30 'mover, 16,33,33' linear motor, 34 substrate, 35 linear scale, 36 position reading unit, 45 drum projection optical mechanism, 50a, 50
b frame, 55 original scanning optical mechanism, 100
Optical scanning device for copiers.

Claims (6)

[Claims] 1. A field magnetic circuit section in which a plurality of field magnetic poles are formed in an axial direction of a peripheral surface thereof, and a sleeve arranged to face the field magnetic circuit section with a magnetic gap therebetween. A stator provided therein; and a coil disposed in the magnetic gap to generate a thrust, further arranged movably along the axial direction of the field magnetic circuit portion, and the opening of the sleeve. A linear motor having a mover projecting outwardly through the linear motor. 2. A hollow first sleeve, a field permanent magnet in which the same magnetic poles are arranged to face each other in the axial direction within the first sleeve, and the same magnetic poles of the permanent magnets are arranged in a gap which faces each other. And a stator having a hollow second sleeve that is arranged to face the first sleeve via a magnetic gap and has an opening formed in the axial direction thereof, and is fitted onto the first sleeve. And a mover provided with a coil holder that is slidably arranged and projects outward through the opening of the second sleeve, and a polyphase coil that is arranged in the coil holder. And a linear motor. 3. The linear motor according to claim 1, wherein the mover is provided with a linear bearing. 4. The linear motor according to claim 2, wherein a cooling fin is arranged adjacent to the second sleeve. 5. The linear motor according to claim 1, wherein a 3-phase or 2-phase drive current is passed through the coil. 6. The linear motor according to claim 1, which is a linear motor for optical scanning in which an optical mechanism is mounted on a mover.