JPH03145909A - Linear motor unit - Google Patents

Abstract

PURPOSE:To suppress vibration of base frame by resetting a magnetic field forming member, which is moved through reaction to the driving force of a moving body, by means of a motor. CONSTITUTION:Magnetic fields are induced through permanent magnets 32a, 32b in magnetic field forming members 30a, 30b, and moving bodies 10a, 10b are moved through linear motor effect induced through mutual function with three-phase coils 23a, 23b. Reaction to the moving force causes driving of a frame body, comprising the magnetic field forming members 30a, 30b and coupling boards 33, 34, in the opposite direction to the moving bodies 10a, 10b. When the field forming members 30a, 30b are moved, a pulse motor 49 drives a pulley 48 to reset the field forming members 30a, 30b through a wire 43 so that the movement of the field forming bodies is cancelled.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a linear motor device such as a copying machine, an optical scanning device such as a printer, a magnetic disk drive device, etc., which uses a linear motor consisting of a movable element and a magnetic field forming member. It is something.

<Prior Art> Conventionally, in a linear motor device such as a magneto-optical disk device, as shown in FIG. A magnetic field forming member 73 made of a permanent magnet or the like is fixed to a base frame 74.

<Problems to be Solved by the Invention> In a conventional linear motor device, in order to move the movable body 71, a voice coil is driven to apply thrust (
When F) is generated, a reaction force is generated in the magnetic field forming member 73,
The reaction force (Fr) is transmitted to the base frame 74, causing adverse effects such as vibration or deformation of the base frame 74. - For example, data errors occur in disk drives.

In addition, high-speed copying machines have problems such as the copying machine moving depending on the location where it is installed, causing the document to move.

The present invention was devised in view of the above circumstances, and an object of the present invention is to provide a linear motor installation that can eliminate inconveniences such as vibration of the base frame caused by the movement of the mover.
"Target."

Means for determining section shelves〉 Linear motor device number according to the present invention, Hess Frey 1
, move in a straight line on the top l]4. A movable element provided in the movable element, a magnetic field forming member disposed opposite to the movable element, and moved in the counter-driving direction of the movable element by a reaction force generated by the driving force of the movable element, etc. The magnetic field forming member 44 is returned to its normal position after being displaced by a reaction force. The motor for moving the movable element is controlled based on the detection result of the moving position of the movable element.

<For 0> When a driving force is generated between the mover and the magnetic field forming member,
The mover or base frame moves in a straight line. At the same time, the magnetic field forming member linearly moves in the opposite direction to the movable element due to the reaction force generated by the driving force. Therefore, the reaction force is not transmitted to the base frame. However, since the magnetic field forming member deviates from its normal position due to the influence of sliding load, posture, etc., the motor as a return means is controlled based on the detection result of the moving position during the movement of the movable element.・
Then, the positional deviation of the magnetic field forming part H is erased, and the positional relationship with the movable child magnetic field forming member is always the first! It is held in the state of U1.

<Example> Hereinafter, an example of the linear motor device according to the present invention will be described using a slit exposure type copying machine as an example.

Figure 1 is a plan view showing the mechanical configuration of the linear motor device;
Figures 2 and 3 are cross-sectional views along the X-X line and Y-Y line in Figure 1, Figure 4 is a block diagram showing the electrical configuration of the linear motor device, and Figure 5 is the actual implementation. FIG. 3 is an explanatory diagram of an example operation.

The linear motor device described here includes a first movable body 10a equipped with an optical unit (not shown) such as a 45° mirror and a lamp unit, and an optical unit (not shown) such as a right-angle mirror.
In order to move the second movable body 10b (not shown) mounted thereon alternately in the directions A (scanning direction) and B (return direction) in the figure at a speed ratio of 2:1, the base frame inside the copying machine main body 1 (+I).

The first movable body 10a and the second movable body 10b are -L in the figure.
Bearings 11a and 11h corresponding to the shaft 3, which is fixed to the base frame 1 via the holder 2, are provided on the side. roller 12a sliding on the rail 4-,
12b are provided respectively, and this makes the base frame l
1i+Jl are movable in directions A and B in the figure. Moreover, the first movable body 10a, the second movable body 10
Movers 20a and 20b are provided on both sides of the mover 20b, respectively, and magnetic field forming members 30a and 30b are provided at predetermined intervals at opposing positions of the movers 20a and 20b, respectively.

In addition, 13a and 13b in the figure are the 1st ``1'' body 10a.
, a 21st linear encoder for detecting the moving position of the moving body 1011, respectively, and the linear encoder 13a
, 13b are attached and fixed to the upper lower portions of the first movable body 10a and the second movable body 10b, respectively, while the stator scale 13c is attached and fixed to the base frame 1 via the fixing member 5. .

The magnetic field forming members 30a, 30b consist of plate-shaped permanent magnets 31a, 31b and fixed yokes 32a, 32b, and both ends thereof are connected to each other by connecting plates 33, 34. That is, magnetic field forming part +; 4' 30 a
, the connecting plate 33, the magnetic field forming member 30b, and the connecting plate 34b collectively form a frame. In addition, the magnetic field forming member 30a
On both sides of the inner surface of the
The lower part of the magnetic field forming member 30b is supported by a total of two rollers 6 attached to the base frame 1, and the magnetic field forming members 308. 30b is Hess Frey J,
It is movable in directions A and B in the figure with respect to l.

Here, the mover 20a and the magnetic field forming member 30a will be explained in detail. The movable element 20a is composed of movable yokes 21a and 22a attached to both sides of the first movable body 10a, and three-phase coils 23a and 23a attached to the outer surfaces of the movable yokes 21a and 22a,
The magnetic field forming member 30a is composed of a plate-shaped fixed yoke 31a connected to connecting plates 33 and 34, and a permanent magnet 32a magnetized with multiple poles corresponding to the three-phase coil 23a on the inner surface of the fixed yoke 31a. This completes the configuration of a three-phase brushless linear motor (
This is called linear motor a). In addition, the movable yoke 21
Although not shown in the predetermined position of 22a,
Hall elements are provided to detect the magnetic flux of the permanent magnets 32a, respectively, in order to provide quiescence for excitation switching of the three-phase coils 23a. However, the mover 20b, the magnetic field forming member 30
The same applies to the three-phase brushless linear motor (hereinafter referred to as a linear motor), so the explanation will be omitted.Furthermore, the fixed yoke 31 is also used in the magnetic field forming member 30a.
Supports 41a and 41b are provided on the outer surface of the base frame 1 to protrude outward, respectively.
It is taken out to the outside of the base frame 1 through the (
(See Figure 3). Further, outside the base frame 1, a pulley 45 is provided between the notch hole 42a and the notch hole 42b, and is wound around a wire 43 stretched with a predetermined tension between both the taken out support columns 41a and 41b. It is being

This pulley 45 and a timing pulley 46 are pivotally supported inside a gear box 47 that is fixedly attached to the outer surface of the base frame 1, and the pulley 45 and timing pulley 46 are connected by a timing heel 48.

Further, a pulse motor 49 is provided on the outer surface of the gear box 47, and its output shaft is connected to a timing pulley 46.

That is, when the pulse motor 49 is driven and the timing pulley 46 alternately rotates, the pulley 45 alternately rotates at a reduced speed through the timing heald 48.
Moreover, as the pulleys 45 alternately rotate, the wire 43
, a configuration in which the magnetic field forming members 30a and 30b, which are connected to each other by the connecting plates 33 and 34 through the pillars 41a and 41b, move alternately in directions A and B in the figure with respect to the base frame 1 (returning means 40). It becomes. A spring 44 is interposed between the support column 41b corresponding to the return side and the wire 43 to stabilize the wire tension and also to absorb sudden fluctuations in the vertical position during the return.

Note that the reason why a speed reduction mechanism that is a combination of a timing belt 48 and a timing pulley 46 is adopted as the return means 40 is to prevent operational instability caused by backlash in gear coupling.

Next, the linear motor control circuit 50 will be explained with reference to FIG.

The position detection signals of the linear encoders 13a and 13b are
Consisting of A-phase and B-phase signals with a phase of 90' and a Z signal for detecting the origin, the signals are guided to the MPU 51, which is a microprocessor, through waveform shapers 51a and 51b. The data of the movement position is M
It is designed to be gradually introduced into the PU51.

In the MPU 51, the first movable body 10a and the second movable body lO
The data of the speed pattern b is input in advance, and the command position data based on this speed pattern is compared with the current position data based on the output signals of the waveform shapers 51a and 51b, and the comparison result is used as a signal to control the three-phase driver. 5
2a and 52b are output sequentially. The three-phase drivers 52a and 52b have a circuit configuration that generates a current according to the signal from the MPU 51, and the three-phase coils 23a1 in the linear motors a and b
23b, respectively.

That is, the linear motor control circuit 50 independently controls the thrust of the linear motors a and b using the position detection signals of the linear encoders 13a and 13b as feedback signals, and
The configuration is such that the speeds of the movable body 10a and the second movable body 10b are controlled in a closed loop. This is the main function of the linear motor control circuit 50, but it also has the function of controlling the pulse motor drive circuit 60.

The pulse motor drive circuit 60 is the linear motor control circuit 5
Count up pulse L derived from 0 as a human signal
A human power signal switching SWO2 that switches between Jp-a and countdown pulse Dna and initialization signals LJpi and Dn-i, a logic unit 62 that performs predetermined processing of the human power signal that has passed through the human power signal switching g5w6x, and a four-phase pulse 7- It consists of a four-phase current dryer \63 that supplies a phase current corresponding to a predetermined human power signal to the pulse motor 49, which controls the pulse motor 49 based on the human power signal -''iJ of the linear motor control circuit 50. Micro step drive +J] (2W1-
The basic configuration is designed to perform two-phase drive or vernier drive (also referred to as lI/F).The pulse motor '49 is driven in microsteps to smooth the rotation of the rotor and at the same time increase the drive frequency. We are working to improve this.

To explain in more detail, when the power is turned on, the human power signal switching SWO2 is automatically set to the i side shown in the figure, and the first movable body 10a and the second movable body 10b are in a predetermined standby position. When returning, MPU51
No signal is given from the magnetic field forming members 30a, 3.
0b is prohibited from moving, but when the first movable body 10a and the second movable body 10b are returned to the predetermined standby position, the initialization signal Up-i is sent from the MPU 51.
, Dn-1 is introduced, and the pulse motor 49 is operated in response to this signal to move the magnetic field forming members 30a and 30b to a predetermined standby position.

When this initialization operation is completed, the input signal is turned off!
! l! 5W61 is automatically set to the S side shown in the figure, and thereafter, in accordance with the count-up pulse Up-a and count-down pulse Dna-a that give the movement position of the first movable body 10a. The pulse motor 49 operates, and as the first movable body 10a moves, the magnetic field forming members 30a and 30b move. The reason why the pulse motor drive circuit 60 is controlled by the count up pulse Up-a and the count down pulse Dna is to reduce the processing load on the MPtJ 51.

By the way, the output of the three-phase driver 52a in the linear motor control circuit 50 indicates each state of the first movable body 10a during acceleration/deceleration operation, constant speed feeding, and standby, and
The four-phase current driver 63 is designed to be switched in accordance with the output switching signal PS-a derived from U51.
This output switching signal I's-a is also introduced to operate in the same way, so that the phase current of the pulse motor 49 is prevented from affecting the electrical angle of the field. . In other words, the phase current is reduced without impairing the field electrical angle during the constant speed feeding period and the standby period 1υ1 in which no load is applied to the pulse motor 49, thereby reducing the heat generation of the pulse motor 49.

With the linear motor device configured as described above, the first
The speeds of the movable body 10a and the second movable body 10b are controlled according to the speed pattern shown in FIG. 5(a).

Here, thrust forces Fa(t), Fb(
t) and move the first movable body 10a and the second movable body 10b in the scanning direction (direction A), the magnetic field forming members 30a and 30b have a reaction force F r (
=-Fa(t)-Fb(t)) acts, and the magnetic field forming members 30a and 30b move in the B direction due to this reaction force Fr. Therefore, the first movable body 10a, the second movable body 10b
The reaction force Fr generated when the base frame 1 is alternately moved is not transmitted to the base frame 1, and the braking performance of the base frame 1 can be improved.

After that, when the first movable body 10a and the second movable body 10b are returned to the return direction (direction B), the magnetic field forming members 30a and 30b are moved in the direction A by the reaction force against the thrust of the linear motors a and b based on this return operation. and returned to its original state.

However, the magnetic field forming members 30a and 30b are returned to their original states only in an ideal state, and when the first movable body 10a and the second Due to the influence of the moving direction component of the own weight of the movable body 10b and the magnetic field forming members 30a and 30b, the magnetic field forming members 30a and 30b
As shown in Figure (C), the displacement increases as the first movable body 10a and the second movable body 10b move.

In the linear motor device of the present invention, the magnetic field forming members 30a and 30b are moved in the direction of canceling the deviation using the pulse motor 49, so that the deviation can be canceled.

This principle will be explained in detail below.

In the vehicle interior linear motor device, the pulse motor 49 is driven by detecting the reaction force against the thrust of the linear motors a and b, but the first movable body 1 (li, the second
Is the movable body 10b high It? The pulse motor 49 is driven by utilizing the fact that the speed is controlled at a speed ratio of exactly 2:1. That is, the pulse motor 49 is a magnetic field forming member when the pulley 45 is rotated without loss by a count-up pulse Up-a and a count-down pulse Dna-a which provide the movement position of the first movable body 10a through the pulse motor drive circuit 60. 30a and 30b. Note that the deflection of the magnetic field forming members 30a, 30b is related to the ratio of each mass of the first movable body 10a, the second movable body 10b, and each mass of the magnetic field forming members 30a, 30b.

Since the pulse motor 49 is driven by the method described above, when there is no loss, the electrical angle of the field of the pulse motor 49 and the pulse motor 4 via the wire 43, the IJ 45, etc.
The rotation angle of the rotor 9 always changes in agreement and does not cause the rotor to generate rotational force, but on the other hand, the loss increases,
When the deflection of the magnetic field forming members 30a, 30b causes a deviation from the case of no H1 loss, a rotational force is generated in the rotor in a direction to cancel the deviation, and the magnetic field forming members 30a, 30b are generated via the wire 43, pulley 45, etc. 30b as a restoring force. That is, although there is loss in the system, the magnetic field forming members 30a and 30b exhibit lossless, particularly approximate deflection, and eventually return to approximately the return position.

It goes without saying that the linear motor device according to the present invention is applicable not only to copying machines but also to optical scanning mechanisms such as printers, magnetic disk drives, etc. Further, in this embodiment, from the viewpoint of simplifying the electric circuit and reducing the overall cost, a pulse motor 49 is adopted as the return means, but in addition to the position detection signal of the first movable body 10a, the pulse motor 49 is used to generate a magnetic field. It is also possible to prepare position detection signals for the members 30a and 30b, construct a servo system using the former as a reference signal and the latter as a feedback signal, and employ a servo motor.

<Effects of the Invention> As described above, in the case of the linear motor device according to the present invention, the reaction force generated by the driving force is not transmitted to the base frame, and the positional deviation of the magnetic field forming member due to the reaction force is eliminated. This structure eliminates inconveniences such as vibration of the base frame due to the movement of the mover, and also allows the magnetic field forming member to be positioned normally without being affected by friction loss or tilting of the device. Can be restored. Also,
As the return means, the motor for moving the magnetic field forming member is controlled in accordance with the detection result of the moving position of the movable element, so there is an advantage that the control system can be simplified.

[Brief explanation of the drawing]

1 to 5 are diagrams for explaining one embodiment of the linear motor device according to the present invention, in which FIG. 1 is a plan view showing the mechanical configuration of the linear motor device, FIG. Figure 3 is a cross-sectional view taken along line X-X in Figure 1,
4 is a block diagram showing the electrical configuration of the linear motor device, and FIG. 5 is an explanatory diagram of the operation of this embodiment. FIG. 6 is a schematic diagram for explaining a conventional linear motor device. 1...Base frames 20a, 20b...Movers 30a, 30b...Magnetic field forming member 40...Returning means 49...Pulse motor

Claims (1)

[Claims] (1) A movable element that is linearly movable on a base frame, and a magnetic field that is arranged opposite to the movable element and is moved in the counter-driving direction of the movable element by a reaction force generated by the driving force of the movable element. The magnetic field forming member is provided with a returning means for returning the magnetic field forming member that has been displaced due to the reaction force to the normal position, and as the returning means, a motor for moving the magnetic field forming member is connected to the movable member. A linear motor device characterized in that it is controlled according to a detection result of a moving position.