JPH03183351A - Linear motor device - Google Patents

Abstract

PURPOSE:In a linear motor used for a copying machine, to reduce the resiliency arising in a magnetic field forming member by arranging a movable member freely in shifting on a field forming member, which is supported freely in shifting by a base frame. CONSTITUTION:A base frame 4 supports a magnetic field forming member 3 freely in shifting through rollers 16a and 16b, bearings 9a and 9b, and a shaft 10. The magnetic field forming member 3 supports movable bodies 1 and 2 through the shaft 10, a bearing 8, and a roller 11. An optical system consisting of mirror, or the like is put on the movable body 1. The movable body 2 is equipped with coil members 6a, 6b, and 6c, and the magnetic field forming member 3 is equipped with permanent magnets 12a and 12b. When currents are applied to the coil members 6a-6c to generate magnetic fluxes, thrust occurs in the movable body 2. For this reason, when the movable body 1 shifts in the direction of an arrow a, the resiliency in the direction of an arrow b occurs in the magnetic field forming member 3. Since the magnetic field forming member 3 is movable to the base frame 4, it moves in the direction of arrow b, and absorbs this resiliency.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a linear motor device.

[Prior Art] In optical scanning devices or magnetic disk drive devices such as copying machines and page printers, it is conceivable to use a linear motor device for scanning drive or access drive.

Generally, such a linear motor device includes a base frame, a movable member, and a magnetic field forming member for driving the movable member to move linearly with respect to the base frame.

Such a linear motor device is disclosed in Japanese Patent Application No. 63-68425 “Linear Motor and Linear Drive Device Using Linear Motor”, which is another application filed by the present applicant.
-129982 "Linear drive device", patent application 1986-21
No. 7276 “Linear drive device”, patent application No. 62-33264
No. 3 "Optical system moving device for copying machine j, etc."

For example, as conceptually shown in FIG.
A magnetic field forming member B configured to be linearly movable relative to the magnetic field forming member B, a movable element C corresponding to, for example, a coil member of a rotary electric motor, and a movable body corresponding to, for example, a rotor of a rotary electric motor. have. The movable body and the movable element C are configured to be driven linearly with respect to the base frame A by the magnetic field forming member B. The linear motor device conceptually shown in FIG. 7 absorbs the repulsive force generated in the magnetic field forming member B when the magnetic field forming member B moves the movable element C and the movable body relative to the base frame A. A moving means E configured to move the magnetic field forming member B relative to the base frame A is provided.

Incidentally, the magnetic field forming member B can be composed of, for example, a permanent magnet.

In the linear motor device configured in this way, if the weight of the movable body is Fl, the weight of the magnetic field forming member B is F2, and the coefficient of friction is μ, there is a frictional load Flμ between the movable body and the base frame A. However, magnetic field forming member B and base frame A
A frictional load F2μ is generated between the two.

Here, when the linear motor device operates and the movable body C and the movable element C are driven and moved, the direction of movement of the movable body C and the movable body C is shown as the positive direction by an arrow a, and the repulsion generated in the magnetic field forming member B is shown. The moving direction of the magnetic field forming member B, which is affected by the force, is indicated by an arrow as a negative direction. Also, mover C
The force acting on the movable body and the magnetic field forming member B is hereinafter defined as acceleration force.

Therefore, the acceleration force of the movable body is Fl(t), the thrust generated in the movable body is F2(+), the acceleration force of the magnetic field forming member B is Fm(t), and the repulsion force generated in the magnetic field forming member B is F
l(t), the acceleration force Fm(
t) can be expressed as follows.

Fl(1) =F2(1) −FlμF+(t)
=-F2(t) Fm(1) =F+(t) +F2μ,',Fm(
t) = -Fl) -F1μ+F2μIf the frictional load F1μ between the movable body and the base frame A is larger than the frictional load F2μ between the magnetic field forming member B and the base frame A, the magnetic field forming member Acceleration force Fm (t
) becomes larger than when there is no difference between the frictional load F1μ and the frictional load F2μ.

As a result, the moving distance of the magnetic field forming member B may become longer than desired.

If the magnetic field forming member B moves more than desired, there is a risk that a large load will be applied to the return moving means for returning the magnetic field forming member B to its original position, that is, the initial position. In particular, when a pulse motor is used as the return movement means in a high-speed copying machine, for example, the pulse motor itself generates heat or loses synchronization, making it impossible to operate normally, and the magnetic field forming member There is a possibility that B cannot be returned to its original position.

[Problems to be Solved by the Invention] As described above, the conventional linear motor device has a problem in that when the movable member having the above-mentioned movable element and movable body is linearly moved and driven by the magnetic field forming member, repulsion occurs in the magnetic field forming member. It has the disadvantage that it is very difficult to stop this movable member accurately at a desired position by force.

The present invention has been made in view of the above-mentioned points, and its purpose is to relatively easily move the movable member to a desired accurate position by reducing the repulsive force generated in the magnetic field forming member. An object of the present invention is to provide a linear motor device that can be stopped at any time.

[Means for Solving the Problem] According to the present invention, the object is to provide a base frame, a magnetic field forming member configured to be linearly movable relative to the base frame, and a magnetic field forming member configured to move linearly relative to the base frame. a movable member arranged above the base frame and configured to be driven linearly with respect to the base frame by the magnetic field forming member, and the relative movement of the movable member by the magnetic field forming member is provided. This is achieved by a linear motor device characterized in that it is configured to absorb the repulsive force generated in the magnetic field forming member when linear movement is performed.

[Operation] The linear motor device according to the present invention absorbs the repulsive force generated in the magnetic field forming member when the movable member disposed on the magnetic field forming member is driven linearly with respect to the base frame. Therefore, the porcelain tomb forming member linearly moves relative to each of the base frame and the movable member.

Furthermore, the basic principle of the linear motor device according to the present invention is
This will be schematically explained based on FIG.

This linear motor device includes a base frame 4, a magnetic field forming member 3 configured to be able to move linearly with respect to the base frame 4, and arranged on the magnetic field forming member 3,
It has a movable member configured to be driven linearly with respect to the base frame 4 by the magnetic field forming member 3.

This movable member includes a movable element 2 and a movable body l.

A moving means 5a is provided between the magnetic field forming member 3 and the base frame 4 so that the magnetic field forming member 3 can move linearly relative to the base frame 4.

Moreover, between the magnetic field forming member 3 and the movable body 1, the movable body 1
Another moving means 5b similar to the moving means 5a is provided so that the magnetic field forming member 3 can move linearly relative to the magnetic field forming member 3. That is, the magnetic field forming member 3 is configured to be able to move linearly relative to each of the base frame 4 and the movable body 1.

When the linear motor device configured as described above operates and the movable body 1 is driven and moved, the direction of movement of the movable body 1 is shown as a positive direction by an arrow a, and the direction in which the movable body 1 moves is indicated by an arrow a.
The direction in which the magnetic field forming member 3 moves due to the repulsive force generated is indicated by an arrow as a negative direction.

This linear motor device reduces the weight of the movable body l to Fl.

If the weight of the magnetic field forming member 3 is F2 and the friction coefficient is μ, the frictional load between the movable body l and the magnetic field forming member 3 is F1μ
, the frictional load between the magnetic field forming member 3 and the base frame 4 is F2μ, the acceleration force of the movable body 1 is Fl(i), the movable body 1
The thrust generated in the magnetic field forming member 3 is F2(1), the accelerating force of the magnetic field forming member 3 is Fm (t), the repulsive force generated in the magnetic field forming member 3 is Fl(t), and the accelerating force of the magnetic field forming member 3 is Fm
(t) can be expressed as follows.

Fl(1) =F2(1)-Flμ F+(t) =-F2(f) Fm(t) =F+(t) +F1μ+F2μ,',
Fm(t) --Fl(t) +F2μ This indicates that the influence of the frictional load F1μ between the movable body 1 and the magnetic field forming member 3 is canceled out.

From the above, as described above, the movable member including the movable element 2 and the movable body 1 is configured so that it can freely move linearly on the magnetic field forming member 3 relative to the magnetic field forming member 3. By doing so, the acceleration force F of the magnetic field forming member 3
m (t) can be reduced. Therefore, the load applied to the above-mentioned return moving means for returning the magnetic field forming member 3 to its original initial position can be minimized.

[Example] Next, an example of the linear motor device according to the present invention will be described. This embodiment is a case where the present invention is applied to a scanning exposure type copying machine.

As shown in each of FIGS. 1 to 3, the linear motor device 0 moves linearly relative to a base frame 4 fixed inside the main body of a scanning exposure type copying machine. The magnetic field forming member 3 is configured to be able to move in a straight line relative to the magnetic field forming member 3 and the base frame 4, respectively.

This movable member includes a movable element 2 and a movable body 1, respectively.

The movable body 1 is configured so that an optical unit L as shown in FIG. 5 can be attached thereto.

Furthermore, as shown in FIGS. 1 and 2, the movable body 1
The movable body 1a and the second movable body 1b each constitute the movable body 1a and the second movable body 1b.

The first movable body 1a has an elongated and flat shape. A first mirror 24, a lamp unit, etc. (not shown) are attached to this I-th movable body 1a.

The second movable body To has an elongated and flat shape similarly to the first movable body 1a.

This second movable body 1b includes a second mirror 25 and a third mirror 25.
A mirror 26 is attached.

For each of the first mirror 24, second mirror 25, and third mirror 26, the light that has passed from the first mirror 24 to the third mirror 26 is inverted to form an image. By adding the lens 27 and the fourth mirror 28 that is arranged between the lens 27 and the photoreceptor drum 29 to reflect the light from the lens 27 onto the photoreceptor drum 29, the copying machine can be improved. It makes up the optical system.

The movable element 2 includes a movable yoke 7a and a movable yoke 7b fixed to the ends 3Qa and 30b on both sides of the first movable body 1a, and the ends 30 on both sides of the second movable body 1b.
The movable yoke 7c and the movable yoke 7d are fixed to the end portion 3Qd and the end portion 3Qd, respectively.

Each movable yoke is equipped with three coil members, ie, a coil member 6a, a coil member 6b, and a coil member 6C.

Each of these movable yokes constitutes a path for the magnetic flux generated from the three corresponding coil members.

Furthermore, the movable body 1a and the movable body 1b have bearings 8, 8 mounted on the movable yoke 7a and the movable yoke 7c, respectively.

The bearing 8 is slidably supported on the shaft 10.

The axis IO passes through each of a connecting plate 14a and a connecting plate 14b that mutually connect a fixed yoke 13g and a fixed yoke 13b that constitute a magnetic field forming member 3, which will be described later, and also passes through the fixed yoke I3a and the fixed yoke 13b. is fixed to each of the holders 15a and 5b via the holders 15a and 5b.

The movable element 2 includes rollers 11. mounted on each of a movable yoke 7b and a movable yoke 7d. It has 1+.

The roller 11 is supported by a fixed yoke 13b of the magnetic field forming member 3.

These rollers It, If and bearings 8, 8 slidably supported on the shaft 10 allow the magnetic field forming member 3, which is conceptually shown in FIG. It constitutes a moving means 5b that can linearly move the movable body 1 relative to the magnetic field forming member 3.

The magnetic field forming member 3 includes the above-mentioned three rows of coil members, namely, the coil member 6a, the coil member 6b, and the coil member 6.
Permanent magnet 11a magnetized multipolarly corresponding to each row of c.
and permanent magnet 12b, permanent magnet 12a and permanent magnet +
It has a fixed yoke 13a and a fixed yoke Hb for linearly arranging and fixing each of the 21+.

Each of these permanent magnets 12a and 12b is
As shown in FIG. 3, the three coil member rows are arranged with a predetermined gap in order to form a three-phase brushless motor in cooperation with the three coil member rows.

Further, the fixed yoke lla and the fixed yoke +3b are connected at both ends thereof by a connecting plate 14a and a connecting plate +4b, and are integrated as a frame 14.

A moving means 5a (FIG. 6) is provided between the base frame 4 and the magnetic field forming member 3, which allows the magnetic field forming member 3 to move in the directions of arrows a and 3.

This moving means 5a includes a pair of bearings 92. Bearing 9b and fixed yoke 1 forming part of magnetic field forming member 3
A pair of rollers 162 attached to roller 3b, roller 16b
It is composed of.

The bearings 9a and 9b are configured to slidably support the shaft 10.

In addition, in the operating state of the linear motor device O configured in this way, each of the above-mentioned three coil member rows, ie, the coil member 6a, the coil member 6b, and the coil member 6c, is connected to the first movable body, for example. A Hall element (not shown) is attached to the movable yoke 7a and the movable yoke 7b fixed to the second movable body 1a, and the movable yoke 7c and the movable yoke 7d fixed to the second movable body 1b, and the excitation is switched by the Hall element. can generate the driving force for the linear motion.

Further, it is preferable that the first movable body 1a and the second movable body 1b operate synchronously in order to keep the optical path length constant.

The aforementioned return moving means 17 for returning the magnetic field forming member 3 to its initial position, shown in each of FIGS. 1 and 2, is particularly shown enlarged in FIG. 4.

That is, the return moving means 17 includes a frame 22 fixedly attached to the base frame 4, a pulse motor 21 attached to the frame 22, and a motor connected to the pulse motor 21 to control the operation of the pulse motor 21. The connected control device 23, the first gear 20a rotated by the rotational driving force of the pulse motor 21, the second gear 2Qb rotated by the rotation of the first gear 2 (la), and the second gear 2Qb rotated by the rotation of the first gear 2 (la) gear 2
In order to move the pulley 19 rotated by the rotation of 0b and the magnetic field forming member 3 wound around this pulley 19,
At both ends, two protruding members 3 are provided integrally with the fixed yoke 13a that constitutes the magnetic field forming member 3.
1 and wires 18 connected to each of the wires 18.

In the return moving means 17 configured in this way, when the pulse motor 21 is activated and a driving force is generated by rotation, each of the ↓-th gear 20a1, the second gear 20b, and the pulley eye also rotates. Rotate according to the direction of.

As a result, the wire 18 is moved by the arrow a corresponding to the direction of rotation.
Therefore, the magnetic field forming member 3 including the fixed yoke Ha can be moved in either the direction of the arrow a or the arrow B.

From these facts, it will be understood that the direction in which the magnetic field forming member 3 returns to its initial position can be selected in any direction.

Next, a description will be given of a state when the linear motor device O according to this embodiment is operated.

A movable yoke 7a and a movable yoke 7b in the movable element 2.

Thrust is generated in the mover 2 by supplying current to three coil members attached to each of the movable yoke 7C and the movable yoke 7d, that is, the coil member 6g, the coil member 6b, and the coil member 6c to generate magnetic flux. do.

When thrust is generated in each movable element 2, each of the movable bodies 1a and 1b integrated with the movable element 2 moves in the scanning direction, for example, in the direction of arrow a shown in FIG. 1, together with the movable element 2. Moving.

When each of the movable body 1a and the movable body 1b moves in the direction of arrow a, the permanent magnet 12 of the magnetic field forming member 3 is arranged with a predetermined gap with respect to the above-mentioned three rows of coil members.
A repulsive force is generated in each of permanent magnet a and permanent magnet +2b in the direction indicated by the arrow opposite to arrow a.

However, since the magnetic field forming member 3 is provided with a moving means 5a between it and the base frame 4 that allows the magnetic field forming member 3 to move in the direction of the arrow a or Even if a repulsive force occurs in this direction, the repulsive force can be absorbed by moving in the direction of the arrow.

Furthermore, when the movable body 1 and the movable element 2 return to their original positions after completing their movement in the scanning direction indicated by the arrow a, that is, move in the return direction indicated by the arrow, the magnetic field forming member 3 A repulsive force in the direction indicated by the opposite arrow a is generated in each of the permanent magnets 12a and 12b.

The magnetic field forming member 3 can absorb the repulsive force by moving in the direction of the arrow a by the moving means 5a, as in the case described above.

However, the magnetic field forming member 3 cannot strictly return to the original standby position, that is, the correct initial position, due to frictional loads and the like.

Therefore, it is necessary to move the magnetic field forming member 3 to the correct initial position using the return moving means 17 described above.

Here, in the linear motor device 0 of this embodiment, the weight of the movable body 1a is Fla, and the weight of the movable body 1b is F1b1.
If the weight of the magnetic field forming member 3 is F2 and the friction coefficient is μ, then the frictional load occurring between the movable body 1a and the magnetic field forming member 3 is Flaμ, and the frictional load occurring between the movable body 1b and the magnetic field forming member 3 is F2. The frictional load occurring between the magnetic field forming member 3 and the base frame 4 is F2μ.

In addition, the scanning direction is shown as a positive direction by an arrow a, and the movable body 1
The acceleration force of a is Fl, a(t), the thrust generated in the movable body 1a is F2a (t), and the acceleration force of the movable body 1b is Fib(1
), the thrust force generated in the movable body 1b is F2b (1), the acceleration force of the magnetic field forming member 3 is Fm(t), and the repulsive force generated in the magnetic field forming member 3 is F+(+), then the force of the magnetic field forming member 3 is Acceleration force Fm (0 is Fla (t) = F2a (+) - Fla u
Flb (+) = F2b (L) −Flb μ
Fr(f) =-F2aft)-F2b(f)Fm(
t) =Fr(t) +FIa μ+F1b
μ+F2μ,', Fm(t) =-Fla(t)-F
lb(t)+F2μ.

Therefore, since the movable body 1a and the movable body 1b are configured to be able to freely move linearly on the magnetic field forming member 3, the frictional load Flaμ of the movable body 1a and the frictional load FToμ of the movable body 1b are reduced. can be canceled out, and as a result, the acceleration force Fmm of the magnetic field forming member 3 can be reduced, so that the load applied to the above-mentioned return movement means 17 can be reduced.

[Effects of the Invention] As described above, the linear motor device according to the present invention has the above-mentioned configuration, that is, a base frame, a magnetic field forming member configured to be able to move linearly relative to the base frame, and this magnetic field. a movable member arranged on the forming member and configured to be driven linearly with respect to the base frame by the magnetic field forming member,
When the relative linear movement of the movable member by the magnetic field forming member is performed, the magnetic field forming member is configured to absorb a repulsive force generated in the magnetic field forming member, The movable member can freely move in a straight line on the magnetic field forming member, and the influence of frictional load generated on the movable member can be canceled.

Therefore, when the movable member configured to be movable relative to the base frame is driven to linearly move by the magnetic field forming member, the acceleration force applied to the magnetic field forming member can be reduced. Therefore, it is possible to stop the magnetic field forming member at a relatively accurate position without shifting it from the desired position.

[Brief explanation of drawings]

1 is a perspective view of an embodiment of a linear motor device according to the present invention, FIG. 2 is a plan view of an embodiment of the linear motor device according to the present invention shown in FIG. ■ in Figure 2
4 is a partially enlarged plan view of an embodiment of the linear motor device according to the present invention shown in FIG.
FIG. 5 is an explanatory diagram of the optical system of a scanning exposure copying machine to which the linear motor device according to the present invention is applied, FIG. 6 is a schematic explanatory diagram of the operating principle of the linear motor device according to the present invention, and FIG. - An explanatory diagram of the operating principle of the intramembrane linear motor device. 1...Movable body, 2...Movable element, 3...
...Magnetic field forming member, 4...Base frame, 5...Movement means, 6a6b, 6c...
・Coil members, 7a, 7b, 7c, 7d...
...Movable yoke, 8...Bearing, 10...
・Shaft, 11...Roller, 12a, 12b...
...Permanent magnet, 13g, 13b...Fixed yoke, 14g, 14b...Connection plate, 15a
, 15b...Holder, 17...Returning means, 18...Wire, 21...Pulse motor, 22...Frame, 23 ...Control device, 24.25.26.28...Mirror,
27... Lens, 29... Photosensitive drum. 7th fork

Claims (1)

[Claims] a base frame; a magnetic field forming member configured to be able to move linearly relative to the base frame; a movable member configured to be driven by the magnetic field forming member, and absorbing a repulsive force generated in the magnetic field forming member when the relative linear movement of the movable member by the magnetic field forming member is performed. A linear motor device characterized in that it is configured as follows.