JPH11206099A - Shaft-type linear motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a shaft-type linear motor which is capable of executing expected operations, regardless of the heat generated accompanying current application to an armature coil. SOLUTION: A heat accumulation suppressing device, for instance a heat medium layer 22, which suppresses heat accumulation due to heat generated by a current applied to an armature coil 21 in at least one of a field magnet 1, and the armature coil 21 is attached to a shaft-type linear motor (LMa, etc.). A sensor 32 which reads the information of the scale 31 of an encoder 3 is mounted on the armature coil 21 of the shaft-type linear motor via a member (heat insulating member H1, etc.), which suppresses the heat transmission from the armature coil 21 therebetween.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a shaft-shaped field magnet in which N-poles and S-poles are alternately arranged,
An armature coil formed of a ring-shaped coil through which the field magnet penetrates, wherein one of the field magnet and the armature coil is a mover.

[0002]

2. Description of the Related Art Linear motors are used to linearly move articles and members in a wide range of fields, such as OA equipment such as copiers, image scanners and printers, XY tables, FA equipment such as article transporters, and optical equipment such as cameras. It is used to move to. As such a linear motor, an N-pole magnetic pole and an S-pole
A pole-shaped field magnet having alternately arranged magnetic poles, and an armature coil formed of a ring-shaped coil through which the field magnet penetrates, one of the field magnet and the armature coil being a mover. Shaft type linear motors are known. In this type of linear motor,
By passing a current corresponding to the polarity of the magnetic pole of the field magnet facing the coil portion constituting the armature coil, interaction between the current and the magnetic field formed by the field magnet is desired. Mover thrust can be generated.

[0003] Such a shaft type linear motor has an advantage that when one of an armature coil and a field magnet is a mover and the other is a stator, the stator can be used as a guide for the mover. In addition, in the case of a linear motor including such a shaft-type linear motor, the operation control (position detection, speed detection, position control, speed An encoder (usually a linear encoder) is employed for control and the like.

[0004] Linear encoders are broadly classified into magnetic encoders and optical encoders. The magnetic encoder has a magnetic encoder scale in which N magnetic poles and S magnetic poles are alternately arranged in the moving direction of the mover at a pitch smaller than the magnetic pole pitch of the field magnet, and a magnetic sensor that reads magnetic information of the scale. It consists of. As such a magnetic sensor, a magneto-electric conversion element such as a magneto-resistive element (MR element) or a Hall element that outputs an electric signal according to the polarity of the magnetic pole of the magnetic encoder scale or the strength of the magnetic field is usually employed.

The optical encoder comprises an optical encoder scale in which two optically different surfaces are alternately arranged in the moving direction of the mover, and an optical sensor for reading optical information of the scale. As such an optical sensor, a photoelectric conversion element such as a photodiode or a phototransistor capable of outputting an electric signal according to the amount of light from an optical scale, or a light emitting diode (LED) that irradiates light to an encoder scale In some cases, a light sensor in which a light emitting element such as described above and a photoelectric conversion element are combined, in other words, a one-packaged optical sensor is used.

[0006]

However, in the shaft type linear motor, the gap between the armature coil and the field magnet penetrating the armature coil is as small as possible in order to obtain the desired mover thrust as stably as possible. Is set. Further, usually, at both ends of the armature coil, bearing members which are fitted to the field magnet and are slidable relative to the surface of the magnet are provided, and the movable member is smoothly moved along the stator by the bearing members. To be able to move to.

Therefore, heat generated by energizing the armature coil is confined in the gap between the armature coil and the field magnet, is accumulated in the armature coil and the field magnet, and the temperature thereof rises. A shaft type linear motor is incorporated in another device, for example, an image reading device to drive a slider equipped with an optical component for reading an original image in the image reading device. Further, an armature coil and a field magnet are provided in a casing or the like. When it is surrounded by, for example, the heat is more difficult to radiate, and the temperature of the armature coil and the field magnet is easily raised.

When the temperature of the armature coil rises during operation of the motor, the electric resistance of the armature coil increases, the current flowing through the armature coil decreases, and the thrust of the armature gradually decreases. When the temperature of the field magnet rises, the magnetic force of the field magnet decreases, which also lowers the thrust of the mover. A lubricant such as lubricating oil is usually applied to the bearing member slidable relative to the surface of the field magnet in order to reduce sliding resistance. Evaporation is also conceivable, which may cause fluctuations in the thrust of the mover.

Further, the temperature of the field magnet tends to rise more in the range where the armature coil relatively moves than in other portions, and the temperature of the portion where the mover accelerates and decelerates tends to rise. As described above, when a temperature difference occurs in each part of the field magnet, a difference occurs in a dimensional change due to thermal expansion in each part of the field magnet. It is also conceivable that the field magnet or the bearing member is deformed or distorted due to the heat generated by the armature coil. When a difference in dimensional change occurs in each part of the field magnet, or when a deformation or distortion occurs in the field magnet or the bearing member, the mover becomes difficult to travel smoothly, and the operation thereof becomes uneven.

When an encoder for controlling the operation is provided and an encoder sensor for reading scale information of the encoder is mounted on the armature coil, the sensor is affected by heat from the armature coil. Depending on the position of the sensor with respect to the field magnet, the sensor is also susceptible to heat from the heated field magnet, and when affected by heat, the sensor may be deteriorated or the detection accuracy may be reduced. For example, a Hall element, which is a kind of magnetoelectric conversion element that can be employed as a sensor for a magnetic encoder, is typically a InSb (indium antimony) Hall element, an InAs (indium arsenide) Hall element, or a GaAs (gallium arsenide) Hall element. Although they can be mentioned, their output varies depending on the ambient temperature, though there is a difference in magnitude. In particular, an InSb-based Hall element has a large output signal (Hall voltage), but has poor temperature characteristics, and the output voltage greatly varies depending on the temperature.
Further, an MR element, which is a type of magnetoelectric conversion element, has a characteristic that the output decreases as the temperature increases. Also, the optical sensor employed in the above-described optical encoder may be deteriorated or deteriorated in detection accuracy under the influence of temperature.

If the sensor for the encoder is deteriorated due to temperature or its output fluctuates in this manner, the information to be detected cannot be detected with high accuracy. Inconveniences such as not operating or malfunctioning may occur.
Therefore, the present invention includes a shaft-shaped field magnet in which N-poles and S-poles are alternately arranged, and an armature coil including a ring-shaped coil through which the field magnet penetrates. Provided is a shaft type linear motor in which one of the armature coils is a mover, and which operates with desired operation regardless of heat generated from the armature coil due to energization. That is the task.

[0012]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention roughly provides the following two types of shaft type linear motors (1) and (2). (1) A shaft type linear motor that suppresses heat storage due to heat generated from at least one of the armature coil and the field magnet.

This type of shaft type linear motor is
Heat storage due to heat generation from at least one of the armature coil and the field magnet is suppressed,
As a result, fluctuations and reductions in the mover thrust are suppressed, and the operation is performed stably with the desired mover thrust and the operation is performed smoothly. As a result, a highly reliable shaft-type linear motor that operates with the intended operation can be obtained. (2) A shaft type linear motor that suppresses the influence of heat on an encoder sensor mounted on an armature coil.

This type of shaft type linear motor is
Deterioration of encoder sensor and detection accuracy are suppressed,
It operates precisely under the control of the encoder.
As a result, a highly reliable shaft-type linear motor that operates with the intended operation can be obtained. Next, these will be sequentially described. (1) A shaft type linear motor that suppresses heat storage in an armature coil and / or a field magnet due to heat generated from an armature coil.

More specifically, this type of shaft type linear motor comprises a shaft-shaped field magnet in which N-poles and S-poles are alternately arranged, and a ring-shaped coil through which the field magnet penetrates. An armature coil, and one of the field magnet and the armature coil is a shaft type linear motor serving as a mover, and the field magnet and the electric motor caused by heat generated by energizing the armature coil. A shaft-type linear motor is provided with a heat storage suppressing device that suppresses heat storage of at least one of the child coils.

As the shaft type linear motor of this type, the following linear motors can be exemplified. A linear motor, wherein the heat storage suppressing device is a heat radiating device connected to the armature coil so as to be able to conduct heat so as to dissipate heat generated from the armature coil. Examples of such a heat radiating device include: a) a heat radiating device including a heat medium layer formed in contact with the armature coil; b) a heat radiating device further including a heat radiating member connected to the heat medium layer; c. )
A heat dissipating device including a heat dissipating member connected to the armature coil without a heat medium layer interposed therebetween can be given.

In any case, a member provided with a heat dissipating fin can be exemplified as such a heat dissipating member. One or two or more heat dissipating members can be provided. Examples of the heat medium layer include metals such as aluminum and copper, rubbers and resins, and rubbers (such as silicon rubber) and resins having good heat conductivity and heat resistance enough to withstand heat generation of the armature il.

Examples of the material of the heat dissipating member include metals such as aluminum and copper. Further, when the armature coil is a mover and the shaft-shaped field magnet is a stator, a driven body is connected to the armature coil, and at least a part of the driven body is provided. A part in which (particularly, a part connected to the armature coil or a part close to the armature coil) also serves as the heat radiating member can be exemplified.

The driven body is not particularly limited, but may be, for example, a slider having an optical component for reading an original image in an image reading apparatus. When at least a part of the driven body also serves as a heat radiating member as described above, a heat radiating fin may be formed at a portion also serving as the heat radiating member. In any case, heat generated from the armature coil is transmitted to the heat radiator, and is radiated from the heat radiator to the outside. Thus, the temperature rise of the armature coil is suppressed, and therefore, the temperature rise of the field magnet is also suppressed. When a bearing member is provided on the armature coil, the temperature rise of the bearing member is also suppressed. A linear motor, wherein the heat storage suppressing device is a cooling device provided for the armature coil.

As such a cooling device, for example, a) a cooling air generating device for blowing a cooling air to the armature coil, b)
In addition to the cooling air generating device, a cooling device including a coil cooling ventilation duct for flowing and discharging the airflow from the cooling air generating device along the periphery of the armature coil can be exemplified. Such a cooling air generator may be mounted on the armature coil, or may be installed at a fixed position and connected therefrom to the armature coil via, for example, a flexible duct. Examples of the cooling air generating device include a device including a blower such as a cooling fan.

In the case where the armature coil is a mover and the shaft-shaped field magnet is a stator, the armature coil surrounds the armature coil, and is disposed along the stator along with the armature coil. A reciprocating case is included, and the case can be exemplified by a cooling device having a ventilation hole for allowing outside air to pass through the case as the armature coil moves.

In any case, the armature coil is cooled by the cooling device, and the temperature rise of the armature coil is suppressed, and therefore, the temperature rise of the field magnet is also suppressed. When a bearing member is provided on the armature coil, the temperature rise of the bearing member is also suppressed. The armature coil is a mover and the shaft-shaped field magnet is a stator, and the heat storage suppressing device includes a bearing unit that can reciprocate along the stator. A linear motor that supports the armature coil so as to be exposed to the outside.

In this linear motor, since the armature coil is exposed to the outside, when the armature coil travels, an external airflow is generated relative to the traveling, thereby cooling the armature coil. Therefore, the temperature rise of the field magnet is also suppressed, and when the armature coil is provided with a bearing member, the temperature rise of the bearing member is also suppressed. The armature coil serves as a mover and the shaft-shaped field magnet serves as a stator, and the heat storage suppressing device stops the armature coil at a position facing a movement passage of the armature coil. A shaft type linear motor that is a cooling device that can cool the armature coil at the stop position and a portion of the field magnet corresponding to the armature coil stop position at a position corresponding to at least one of the stop positions.

As such a cooling device, a cooling air generating device capable of blowing cooling air to the armature coil at the stop position and the portion of the field magnet corresponding to the armature coil stop position can be exemplified. Examples of the cooling air generating device include a device including a blower such as a cooling fan. Such a cooling air generator may be provided individually corresponding to the armature coil stop position, a common device is installed corresponding to a plurality of armature coil stop positions, and the cooling air therefrom is passed through a duct. You may guide to a position.

The shaft type linear motor starts or moves from a position where the armature coil is stopped (a home position of the mover, a start point and an end point in a target movement range of the mover, etc.). When the armature coil is accelerated or decelerated, such as when stopping, heat generated from the armature coil increases. In this linear motor,
Since the cooling device capable of cooling the armature coil at the stop position and the portion of the field magnet corresponding to the armature coil stop position is provided, the temperature of the armature coil and the field magnet can be increased effectively and economically. Is suppressed. When a bearing member is provided on the armature coil, the temperature rise of the bearing member is also suppressed.

A cooling device may be provided for blowing cooling air toward the field magnet and the armature coil over the entire range of movement of the armature coil. As such a cooling device, for example, a cooling air generator that is disposed in an outer region of the field magnet and the armature coil and blows cooling air to the field magnet and the armature coil, and an armature coil of the field magnet And a wind tunnel for guiding the cooling air from the cooling air generator to the entire area of the range in which the cooling air moves. A linear motor which is a heat radiator connected to the field magnet so as to conduct heat so that the heat storage suppressing device suppresses heat storage in the field magnet.

Such a heat radiating device includes a heat radiating member (which may be provided with a heat radiating fin) connected to the field magnet and a heat conductive material layer coated on the outer peripheral surface of the field magnet. Can be exemplified. In this linear motor, heat transmitted from the armature coil to the field magnet is transmitted to the radiator, and is radiated from the radiator to the outside. Therefore, the temperature rise of the field magnet is suppressed, and the temperature rise of the armature coil is suppressed accordingly.

When the heat radiating device includes a heat conductive material layer coated on the outer peripheral surface of the field magnet,
As a result, heat is uniformly transmitted to the entire field magnet,
There is also an advantage that the temperature of the entire field magnet is made uniform, so that the fluctuation of the thrust of the mover due to the position on the field magnet is suppressed. Examples of the heat conductive material layer include aluminum and copper. A linear motor, wherein the heat storage suppression device includes a heat insulating material layer coated on an outer peripheral surface of the field magnet.

In this linear motor, since the outer peripheral surface of the field magnet is covered with the heat insulating material layer, the temperature rise of the field magnet is suppressed. As the heat insulating material layer, for example, a zirconium-based ceramic layer, especially a zirconium-based porous ceramic layer, can be given. A linear motor, wherein the heat storage suppressing device is a cooling device provided for the field magnet.

As such a cooling device, a) a refrigerant (air, water, or the like) is supplied to a cooling medium passage formed in the field magnet.
Cooling oil, etc.). B) With the relative movement of the field magnet and the armature coil, a vortex of air is generated in an area above the field magnet adjacent to the end of the armature coil. One that includes an air reflector member provided adjacent to each end of the armature coil can be exemplified.

In this linear motor, the cooling device suppresses the temperature rise of the field magnet due to the heat from the armature coil, and also the temperature rise of the armature coil. When the armature coil is provided with a bearing member,
The temperature rise of the bearing member is also suppressed. The heat storage suppressing device is a cooling device provided for the armature coil and the field magnet, and the cooling device is configured to connect the armature coil and the field with the relative movement of the field magnet and the armature coil. A linear motor including a member having a ventilation opening for air intake and exhaust provided adjacent to each end of the armature coil so as to allow air to flow through a gap with the magnetic magnet.

In this linear motor, the armature coil is cooled from the inside by the cooling device, and the field magnet is also cooled from the surface. Therefore, the temperature rise of the armature coil and the field magnet is suppressed, and when the armature coil is provided with a bearing member, the temperature rise of the bearing member is also suppressed. The heat storage suppressing devices described above can be appropriately combined and employed.

Further, of the heat storage suppressing devices described above,
In linear motors that employ the above-mentioned devices, the effect of heat on magnetic sensors such as Hall elements that detect changes in the magnetic poles of field magnets usually mounted on armature coils can be suppressed. There is also an advantage that the mover operation of the first stage is achieved. (2) A shaft type linear motor that suppresses the influence of heat on an encoder sensor mounted on an armature coil.

The following can be exemplified as this type of linear motor. A field-shaped magnet having a shaft shape in which N-poles and S-poles are alternately arranged; and an armature coil formed of a ring-shaped coil through which the field magnet penetrates. One of the shaft type linear motors is a movable element, and an encoder for controlling the operation is attached, and an encoder sensor that reads scale information of the encoder suppresses heat transfer from the armature coil to the sensor. A shaft type linear motor mounted on the armature coil via a member to be driven.

As the heat transfer suppressing member, a) a heat insulating or heat insulating member (for example, a layered heat insulating member) made of ceramic, resin, rubber or the like having heat insulating property; b) a metal such as aluminum having a large heat radiating effect. A heat dissipating member (e.g., a layered heat dissipating member) composed of: a) a heat dissipating layer made of a metal such as aluminum having a heat dissipating effect and a heat insulating layer made of ceramic, resin, rubber or the like having heat insulating properties. Wherein the sensor is provided on the heat insulating layer side, d) a case-shaped member made of ceramic, resin, rubber, or the like having heat insulating properties, and covering the sensor in a state where a sensor detecting end for reading scale information can read scale information. Etc. can be exemplified. If a heat dissipating member is employed, it may include heat dissipating fins. When the encoder is a magnetic type, the heat insulating material and the heat radiating material are preferably non-magnetic materials. When the sensor detecting end is covered with a heat insulating member and an optical encoder is employed, the heat insulating member covering the sensor detecting end may be formed of a transparent material such as transparent glass or transparent resin. A field-shaped magnet having a shaft shape in which N-poles and S-poles are alternately arranged; and an armature coil formed of a ring-shaped coil through which the field magnet penetrates. One of which is a shaft type linear motor having a movable element, an encoder for operation control is provided, and a scale of the encoder is formed on the field magnet, and a sensor for reading scale information of the encoder is provided. Is mounted on the armature coil, and the sensor is covered with a member that suppresses heat transfer from the field magnet to the sensor in a state where the detection end that reads the scale information can read the scale information. Type linear motor.

Also in this motor, as the heat transfer suppressing member, a) a heat insulating member (for example, a layered heat insulating member) made of ceramic, resin, rubber or the like having heat insulating property; b) a ceramic, resin, rubber or the like having heat insulating property. And a case-shaped member that covers the sensor in a state where the sensor detection end that reads scale information can read scale information can be exemplified.

In any case, the heat transfer suppressing member is preferably made of a non-magnetic material in the case of a magnetic encoder. When the sensor detection end is covered with a heat insulating member and an optical encoder is employed, the heat insulating member covering the sensor detection end may be made of a transparent material such as transparent glass or transparent resin. Also in the case of this motor, the sensor may be mounted on the armature coil via a member that suppresses heat transfer from the armature coil to the sensor.

Here, the encoder will be described collectively. The encoder scale may be a magnetic encoder scale or an optical encoder scale. When a magnetic encoder scale is used, the sensor may be a magnetic sensor that reads magnetic information of the encoder scale. When an optical encoder scale is used, the sensor is a light sensor that reads optical information of the encoder scale. A sensor may be used.

As such a magnetic sensor for a magnetic encoder, for example, a magneto-electric conversion element such as a magneto-resistance element (MR element) or a Hall element can be employed. In addition, as an optical sensor for an optical encoder, a photoelectric conversion element such as a photodiode or a phototransistor, which can output an electric signal corresponding to the amount of light from the optical encoder scale, or an optical sensor for the encoder scale. A light emitting element such as a light emitting diode (LED) for irradiating light and a photoelectric conversion element are combined, in other words, a one-packaged optical sensor or the like can be adopted.

The structures of the linear motors of the types (1) and (2) described above can be employed in appropriate combinations.

[0041]

Embodiments of the present invention will be described below with reference to the drawings. FIGS. 1 to 19 and FIGS. 21 to 23 show a shaft type linear motor or a part thereof that suppresses heat storage of an armature coil and a field magnet due to heat generated from the armature coil.

Among the shaft type linear motors of this type, the linear motors LMa and LM shown in FIGS.
a ', LMb, LMc, LMd, LMe, LMf, LM
g and LMh can mainly suppress heat storage in the armature coil, and thereby also suppress heat storage in the field magnet. The linear motors LMi, LMj, and LMq shown in FIGS. 15, 16, 22, and 23 can directly suppress heat storage of the armature coils and the field magnet.

The linear motors LMk, LMm, LMn, and LMp shown in FIGS. 17 to 19 and 21 can mainly suppress heat storage in the field magnet, and thereby also suppress heat storage in the armature coils. The linear motor LMo of FIG. 20 can suppress the heat storage of the field magnet.

In these shaft type linear motors, the heat storage due to the heat generated from the armature coil of at least one of the armature coil and the field magnet is suppressed, thereby suppressing the fluctuation and decrease in the thrust of the mover. It is a highly reliable shaft type linear motor that operates stably and smoothly with the desired mover thrust. Hereinafter, each shaft type linear motor will be described.

The shaft type linear motor LMa of FIG.
Materials that can be machined and magnetized (for example, Fe-Cr-
A movable element 2 is formed along a shaft-shaped field magnet 1 formed of a Co-based metal, manganese aluminum (MnAl)), but is not limited thereto, but is formed by magnetizing a shaft member 1a having a circular cross section. It can travel back and forth. The shaft-shaped field magnet 1 is used as a stator.

The field magnet 1 has N
It is formed by alternately magnetizing the magnetic poles of the poles and the magnetic poles of the S pole with the same magnetic pole width Pm. The mover 2 has an armature coil 21. The armature coil 21 is surrounded by a heat medium layer 22 formed in contact with the armature coil 21 and housed in a casing 23. The casing 23 has a plurality of ventilation holes 231 and has bearing members 232 at both ends. The armature coil 21, the heat medium layer 22 and the casing 23 constitute the mover 2. Bearing member 232
Is slidably fitted to the field magnet 1, and the mover 2 can travel along the field magnet 1 by the bearing member 232. The driven body S is connected to the casing 23.

The heating medium layer 22 is not limited to this,
Here, it is made of silicon rubber having good heat conductivity.
The ventilation holes of the heat medium layer 22 and the casing 23 constitute a heat dissipation device. In this example, the armature coil 21 has two sets of coil groups each including three coils of the U, V, and W phases. The first set of coil groups and the second set of coil groups are arranged in this order. ,
The stator is arranged in the longitudinal direction. The first set of coil groups includes coils L _U1 , L _V1 and L _W1 , and is arranged in this order in the longitudinal direction of the stator. The second group of coils is composed of coils L _U2 , L _V2 and L _W2 , which are arranged in this order in the longitudinal direction of the stator.

Each coil of each set is ring-shaped,
It is arranged so as to fit outside the stator 1 with a predetermined gap. Although not limited thereto, these coils are each formed to have a width of １ ／ of the magnetic pole width Pm or a width smaller than that, in this example. Any two adjacent coils of these coils are arranged such that their center positions are shifted by Pm / 3 in the longitudinal direction of the stator.

The Hall elements h ₁ , h ₂ , and h _{3, which} are _one type of magnetoelectric conversion element capable of outputting an electric signal corresponding to the polarity of the magnetic pole, are provided with the respective coils of the armature coil 21 and the field magnet 1. It is provided for detecting the positional relationship between the magnetic poles of the field magnet 1 in the longitudinal direction of the stator and energizing the coils in accordance with the position and the polarity of the magnetic pole of the field magnet 1 with which each coil faces.

Each Hall element is arranged on the outer peripheral surface of the armature coil 21 here, although not limited thereto. More specifically, as described above, the field magnet 1
It is located at the next position facing. That is, in the longitudinal direction of the field magnet 1, a Hall element h ₁ at a position shifted P _m / 6 on the right side in FIG. 1 are arranged from the center of the coil L _U1. P Similarly, there is disposed a Hall element h ₂ to P _m / 6 position shifted to the right side in FIG. 1 from the center of the coil L _V1, the right side in FIG. 1 from the center of the coil L _W1
m / 6 Hall element h ₃ at a position displaced are arranged.

The linear motor LMa further includes a magnetic encoder scale 31 formed on the shaft member 1a. The magnetic encoder scale 31 is formed by magnetizing the N magnetic pole and the S magnetic pole at a magnetic pole pitch smaller than the magnetic pole pitch of the field magnet 1 on the shaft member 1a. The magnetic sensor 3 is provided at a position facing the encoder scale 31 on the casing 23 of the mover 2.
2 is mounted. In this example, the magnetic sensor 32 is an MR element, which is a type of a magnetoresistive element.

In the linear motor LMa described above, when the armature coil 21 is energized under energization control, the coil 21
Of the armature coil 21 travels along the field magnet 1 as a stator due to the interaction between the current flowing through the armature and the magnetic field formed by the field magnet 1. Further, in the linear motor LMa, heat generated from the armature coil 21 due to energization is transmitted to the heat medium layer 22 and is radiated to the outside through the ventilation hole 231 of the casing 23. Thus, the temperature rise of the armature coil 21 is suppressed, and therefore, the temperature rise of the field magnet 1 and the bearing member 232 is also suppressed. Thus, the motor LMa suppresses the fluctuation and reduction of the mover thrust,
As a result, it is a highly reliable shaft-type linear motor that operates stably and smoothly with the desired mover thrust.

FIG. 30 is a schematic block diagram of an electric circuit related to the linear motor LMa. As shown in FIG. 30, the coils of the armature coil 21 are connected to each other and connected to the motor drive control circuit 6. Further, an encoder signal processing circuit 51 capable of binarizing an output signal from the magnetic sensor (MR element) 32, and a Hall element h
_A field magnet signal processing circuit 52 capable of binarizing each of the output signals ₁ , h ₂ and h ₃ is provided, and these are also connected to the motor drive control circuit 6. The motor drive control circuit 6 controls energization of the armature coil 21 based on the encoder signal, the field magnet signal, and the like output from the encoder signal processing circuit 51 and the field magnet signal processing circuit 52.

The motor drive control circuit 6, encoder signal processing circuit 51, field magnet signal processing circuit 52, etc. are mounted on one electric circuit board 20. The motor drive control circuit 6 receives a command from a system control unit 9 that controls the entire device (for example, an image reading device described later) that includes the linear motor LMa as a drive source and is disposed at a fixed position outside the mover 2. Drive the motor.

The system controller 9 outside the mover 2 and a circuit formed on the electric circuit board 20 are connected by a harness 71. The harness 71 is connected to the electric circuit board 20 by a pair of male and female connectors 72. In this example, the following signals are transmitted by the harness 71. One is a circuit formed on the electric circuit board 20,
Further, a power supply voltage is supplied to the hall elements h ₁ , h ₂ , h ₃ and the MR element 32. Also, the system control unit 9
To the motor control circuit 6, a signal indicating start or stop of driving of the motor (start / stop signal), a signal indicating driving direction (driving direction signal), and a reference clock signal are transmitted.

Next, the above circuits on the electric circuit board 20 will be described in order. The first set of U-phase coil L _U1 , V-phase coil L _V1 and W-phase coil L _{W1 of} armature coil 21 and the second set of U-phase coil L _U2 , V-phase coil L _V2 , W-phase coil L
_W2 is connected on the mover 2 or on the substrate 20 as follows. That is, each pair of U-phase coils, V
The phase coils and the W-phase coils are respectively connected in parallel, and the coils connected in parallel are star-connected.

The encoder signal processing circuit 51 is a circuit for binarizing an electric signal output from the MR element 32 and converting it into a digital signal (binary signal). The position detection, speed detection, and drive control of the mover 2 can be performed based on the signals binarized (digitized) by the encoder signal processing circuit 51. In this example, the motor drive control circuit 6 uses the PLL control (phase synchronization control).

The field magnet signal processing circuit 52 is a circuit for binarizing each electric signal output from the hall elements h ₁ , h ₂ , h ₃ and converting it into a digital signal. In this example, the motor drive control circuit 6 uses the armature coil 2 based on the field magnet signal binarized (digitized) by the field magnet signal processing circuit 52.
1 is controlled.

FIG. 31 is a schematic block diagram showing an example of the internal configuration of the motor drive control circuit 6. The motor drive control circuit 6 includes a PLL control circuit (phase synchronization control circuit) 6
2. It has a compensation circuit section 63 and a conduction control circuit section 64. A reference clock signal having a frequency corresponding to the target speed of the linear motor mover 2 is input from the system control unit 9 to the PLL control circuit unit 62.

The PLL control circuit 62 further includes an MR
The encoder signal output from the element 32 and binarized by the encoder signal processing circuit 51 is fed back as a signal indicating the actual moving speed of the mover 2.
In the PLL control circuit section 62, a signal corresponding to the phase difference between the reference clock signal from the system control section 9 and the encoder signal indicating the moving speed from the encoder signal processing circuit 51 is output to the compensation circuit section 63.

In the compensating circuit 63, lead / lag compensation of the transmission system is performed, and a compensated signal corresponding to the phase difference between the reference clock signal and the moving speed signal is supplied to the conduction control circuit 64.
Is input to The energization control circuit unit 64 outputs a constant current corresponding to the compensated signal based on the field magnet signal output from each Hall element and binarized by the field magnet signal processing circuit, as shown in FIGS. Power is supplied to each coil at the timing shown in FIG. As a result, a current that matches the phases of the reference clock signal corresponding to the target speed and the signal corresponding to the actual moving speed of the mover 2 flows through the coils of each phase. At the desired speed.

FIG. 32 shows the timing of energizing each coil when driving the mover 2 to the left in FIG.
FIG. 33 shows the timing of energizing each coil when driving the mover 2 in the right direction in FIG. When power is supplied at such a timing, each coil is positioned such that the center position of the coil in the longitudinal direction of the stator is P from the upstream end of the magnetic pole of the field magnet 1 in the driving direction in that direction.
_The direction in which the coil generates an electromagnetic force in the driving direction from the position advanced in the _m / 6 driving direction to the position further advanced in the 2P _m / 3 driving direction, depending on the polarity of the magnetic pole facing the coil. Will flow. Therefore, when power is supplied to each coil, all portions of the coil are located at positions facing the magnetic poles of one polarity (N pole or S pole) and do not straddle both the N pole and the S pole. Thus, the current supplied to each coil is not converted into a thrust for driving the mover 2 in the direction opposite to the direction in which the mover 2 is to be driven, but is converted into a thrust for driving the mover 2 in the direction in which the mover 2 is to be driven. Therefore, efficiency is high. For the same reason, when the mover 2 moves along the stator 1, there is almost no fluctuation in the thrust.

Although the linear motor LMa has been described above, the armature coils 21 similar to those in the motor LMa are provided in each of the linear motors described later, but these are schematically illustrated. Although hall elements h ₁ , h ₂ and h ₃ are provided, illustration and description of the hall elements are omitted. Illustration of the driven body may be omitted. Also in the linear motor described later with reference to FIGS. 2 to 23, an encoder magnetic sensor 32 is provided, but illustration and description of the sensor are omitted. Further, the respective linear motors to be described later are also driven by circuits similar to those shown in FIGS. 30 and 31, but the description thereof is omitted.

In the linear motor LMa, a magnetic encoder scale 31 and a magnetic sensor 3 are used as encoders.
Although the magnetic encoder 3 composed of two is employed, an optical encoder may be employed. When an optical encoder is adopted, an optical encoder scale and an optical sensor may be used instead of the magnetic encoder scale 31 and the magnetic sensor 32, and the encoder signal processing circuit 51 in the circuits of FIGS. May be used as a circuit for processing the above signal.

The encoder scale, whether magnetic or optical, may be provided on the field magnet or on the shaft member 1a, or may be provided at another appropriate position in parallel with the member 1a. In the following description, parts and portions denoted by the same reference numerals as those in FIG. 1 are structurally substantially the same as those of the linear motor in FIG. 1 and are substantially the same in function.

The shaft type linear motor LM shown in FIG.
a 'is a case where the casing 23 is made of aluminum or copper casing 23' having good heat conductivity in the linear motor LMa of FIG. 1 and the ventilation hole 231 is not formed. The casing 23 'is in contact with the heat medium layer 22, and also serves as a heat radiating member. The heat medium layer 22 and the casing 23 'constitute a heat radiating device, whereby heat from the armature coil 21 is radiated to the outside, and the temperature rise of the armature coil 21 is suppressed. Therefore, the temperature rise of the field magnet 1 is also suppressed.

The shaft type linear motor LMb shown in FIGS. 3 and 4 (section AA in FIG. 3) has an armature coil 21 surrounded by a heat radiating member 24 also serving as a casing.
The heat dissipating member 24 has a large number of heat dissipating fins 24f on its outer peripheral surface.
have. A part S <b> 1 of the driven body is connected to the heat radiation member 24. The portion S1 also has a radiating fin S1f. The heat radiating member 24 and a part S1 of the driven body are formed of a metal material having good thermal conductivity, such as copper or aluminum.

The heat dissipating member 24 and the portion S1 constitute a heat dissipating device, and heat generated from the armature coil 21 due to energization is transmitted to the heat dissipating member 24 and further transmitted to a part S1 of the driven body. Dissipated outside through these. Thus, the temperature rise of the armature coil 21 is suppressed, and
The temperature rise of the field magnet 1 and the bearing member 232 is also suppressed. In this way, the motor LMb is prevented from changing or reducing the mover thrust, and thus operates stably and smoothly with the desired mover thrust.

The shaft type linear motor LMc shown in FIGS. 5 and 6 (cross section taken along the line BB in FIG. 5) has a heat medium layer 22 formed in contact with the armature coil 21 and a casing which also serves as a heat radiating member. 25 is formed by contact. A part S <b> 1 of the driven body is connected to the casing 25. The portion S1 is also in contact with the heat medium layer 22. The casing 25 and the portion S1 are formed of a metal material having good thermal conductivity, such as copper or aluminum, and constitute a heat dissipation device together with the heat medium layer 22.

In this linear motor LMc, heat generated from the armature coil 21 due to energization is transmitted to the heat medium layer 22, the casing 25 also serving as a heat radiating member, and also to a part S1 of the driven body, and through these. Dissipated outside.
Thus, the temperature rise of the armature coil 21 is suppressed, and therefore, the temperature rise of the field magnet 1 and the bearing member 232 is also suppressed.

The shaft type linear motor LMd shown in FIG.
A heat dissipation member 220 made of a metal material such as copper or aluminum having good thermal conductivity was formed in contact with the upper half of the armature coil 21 to reduce the weight, and the armature coil 21 and the heat dissipation member 220 were housed in the casing 26. Things. A part S <b> 1 of the driven body that also functions as a heat radiating member is connected to the heat radiating member 220 and the casing 26 so as to directly contact the heat radiating member 220.

The heat dissipating member 220 and the portion S1 constitute a heat dissipating device, and heat generated from the armature coil 21 due to energization is transmitted to the heat dissipating member 220 and the portion S1, and is radiated to the outside through these components. Thus, the temperature rise of the armature coil 21 is suppressed, and therefore, the temperature rise of the field magnet 1 and the bearing member 232 is also suppressed. 8 and 9 (FIG.
In the shaft type linear motor LMe shown in (C-C section), the armature coil 21 is housed in the casing D1. The casing D1 also serves as a coil cooling ventilation duct, and is provided with a cooling air generator F1 having a propeller fan f1 at an upper portion and an exhaust hole d1 at a lower portion.

In this motor, driving the propeller fan f1 allows the outside air to flow through the casing D, which also serves as a ventilation duct.
1 and is blown to the armature coil 21 and flows out of the exhaust hole d1 while removing heat from the coil 21.
Thus, the temperature rise of the armature coil 21 is suppressed, and therefore, the temperature rise of the field magnet 1 and the bearing member 232 is also suppressed.

The motor LMf shown in FIG. 10 is different from the motor LMe shown in FIG. 9 in that the cooling air generator F1 is installed outside the mover 2, and the cooling air is supplied to the casing D1 via the flexible duct D2 from the casing D1. It is intended to be supplied. FIGS. 11, 12 and 13 show still another shaft type linear motor. FIG. 11 is a horizontal sectional view, FIG. 12 is a side view, and FIG.
Is a front view.

In this motor LMg, the armature coils 21
And a case 27 that can reciprocate along the field magnet 1 together with the coil 21 is provided. Bearing member 232
Are provided at both ends of the case 27. Case 27
A plurality of ventilation holes 271 are provided on each side wall in two rows on each side wall, and a plurality of ventilation holes 272 are provided on both end walls.
It has. An outside air introduction guide fin 271a or 271b is attached to each ventilation hole 271 in each side wall. The fin 271b introduces outside air into the case through the ventilation hole 271 provided with the fin when the mover 2 moves leftward in the figure, and the fin 271a is used when the mover 2 moves rightward in the figure. Outside air is introduced into the case through the ventilation holes 271 provided with the fins.

In this linear motor, when the mover 2 travels in the right direction α as shown in FIGS. 11 and 12, for example, the outside air is relatively ventilated by the ventilation holes 272 in the end wall on the front side in the traveling direction.
And into the case through the fins 271a through the fins 271a, and into the case through the vent holes 271 to contact the armature coil 21 and remove the heat thereof, while the vent holes 272 and the fins in the end wall on the rear side in the traveling direction. It flows out from the ventilation hole 271 provided with 271b. Similarly, when the mover 2 travels in the opposite direction, outside air flows through the case 27.

Therefore, the temperature rise of the armature coil 21 is suppressed, and the field magnet 1 and the bearing member 23
2 is also suppressed. In the shaft type linear motor LMh shown in FIG. 13, the armature coil 21 is supported by a bearing unit 28 that can reciprocate along the field magnet 1 to form the mover 2. Bearing members 232 ′ which are fitted and slid on the field magnet 1 are provided at both ends of the bearing unit 28.

The bearing unit 28 supports the armature coil 21 so as to be exposed to the outside. This motor LM
In h, since the armature coil 21 is exposed to the outside, when the armature coil 21 travels, an external air flow is generated relative to the traveling, whereby the armature coil 21 is cooled. Therefore, the temperature rise of the field magnet 1 is also suppressed, and the temperature rise of the bearing member 232 'is also suppressed.

A shaft type linear motor LM shown in FIG.
i is a mover home position HP at which the mover 2 including the armature coil 21 is stopped, a mover start position SP and a mover end point in a range in which a driven body connected to the mover is moved as desired. Position E
In each of P, the armature 2 (hence the armature coil 2
1) and a cooling device FW1 that can cool a portion of the field magnet 1 corresponding to the position.

The cooling device FW1 includes a cooling air generating device F2 having a cooling fan f2. Cooling air from the device F2 is supplied to each of the above positions via a duct D3, and the movable element 2 located there is provided. (Accordingly, the armature coil 21) and the field magnet portion at that position are blown. Note that a cooling air generator may be provided for each of the positions.

In this motor LMi, the armature coils 21
Are stopped, in other words, the positions where the armature coil 21 is accelerated and decelerated, that is, the positions HP, SP, and EP where the heat generation from the armature coil 21 is large and the heat storage of the field magnet 1 is large. In this case, since the armature coil 21 and the field magnet portion are intensively cooled, the temperature rise of the armature coil 21 and the field magnet 1 is effectively and economically suppressed. The temperature rise of the bearing member is also suppressed.

The shaft type linear motor LMj shown in FIG.
Is a modification of the linear motor of FIG. The linear motor LMj is a mover 2 of the linear motor LMb shown in FIG.
The field magnet 1 and the mover 2 (accordingly, the armature coil 2) are moved over the entire moving range of the armature coil 21 (here, the range from the home position to the end point EP).
A cooling device FW2 for blowing cooling air toward 1) is provided.

The cooling device FW2 is provided with a cooling air generating device F3 including a centrifugal blower f3 disposed outside the motor LMb, and a wind tunnel FL for guiding the cooling air to the entire movable range of the movable element 2. In this motor, the armature coil 21
Is cooled by the cooling device FW2 in the entire moving range, and the portion of the field magnet 1 which is easily moved to a high temperature because of being in the moving range of the armature coil 21 is also cooled by the cooling device FW.
Cooled by W2. Thus, the temperature rise of the armature coil 21 and the field magnet 1 is effectively suppressed. The temperature rise of the bearing member is also suppressed.

FIG. 17 shows a field magnet 1 of still another shaft type linear motor LMk according to the present invention. In this motor LMk, the outer peripheral surface of the field magnet 1 is covered with a heat conductive material layer 11. The heat conductive material layer 11 is made of aluminum (although it is not limited thereto), it may be made of aluminum or the like. In this linear motor, heat transmitted from the armature coil 21 to the field magnet 1 is transmitted to the layer 11 functioning as a radiator.
Dissipates from the layer 11 to the outside. Therefore, the field magnet 1
Of the armature coil 21 is suppressed accordingly. Also, since the heat conductive material layer 11 is provided,
There is also an advantage that heat is uniformly transmitted to the entire field magnet 1, the temperature of the entire field magnet 1 is made uniform, and therefore, variation in the thrust of the mover due to the position on the field magnet 1 is suppressed.

In the shaft type linear motor LMm shown in FIG. 18, heat radiation fins 12 are provided at both ends of the field magnet 1 to suppress the temperature rise of the field magnet 1. By this, the temperature rise of the armature coil 21 is suppressed accordingly. FIG. 19 shows a field magnet 1 of still another shaft type linear motor LMn according to the present invention. In this motor LMn, the field magnet 1 is formed in a hollow cylindrical shape, and a cylindrical back yoke 1 is formed on the inner peripheral surface.
3 is fitted. Then, a refrigerant (here, cooling water) Lq is circulated in the back yoke 13. Refrigerant L
Here, q includes a refrigerant circulating device CL including a refrigerant tank and a pump, and a pipe P connecting the refrigerant circulating device CL to both ends of the back yoke 13.

In this motor, the field magnet 1 is
By cooling with q, the temperature rise of the field magnet 1 is suppressed, and the temperature rise of the armature coil 21 and the bearing member is also suppressed accordingly. FIG. 20 shows a field magnet 1 of still another shaft type linear motor LMo according to the present invention. In this motor LMo, the outer peripheral surface of the field magnet 1 is covered with a heat insulating material layer 14. Therefore, the temperature rise of the field magnet 1 is suppressed. The heat insulating material layer 14 can be formed of, for example, a porous ceramic such as a zirconium-based ceramic having a large heat-insulating effect.

The shaft type linear motor LM shown in FIG.
In p, the air reflector member 2 that generates a swirl of air in the region above the field magnet adjacent to the end of the armature coil 21 with the movement of the armature coil 21
91 are provided adjacent to each end of the armature coil 21. Each reflector member 291 has a circular shape when viewed from the front, and has a concave portion 291 ′ facing outward, and the outside air collides with the concave portion 291 ′ to form a vortex of the air. FIG. 21 shows a state in which a vortex is generated immediately before the mover 2 as the mover 2 advances in the right direction α in the drawing. The two reflector members 291 are fitted and supported by the outer casing 292, and the armature coil 21 is supported between the two reflector members 291. The bearing member 232 is also provided on the reflector member 291.

In the motor LMp, an eddy current of air is generated in the region above the field magnet 1 adjacent to the end of the armature coil 21 with the movement of the armature 2. The heated field magnet 1 is cooled. Therefore, the temperature rise of the field magnet 1 is suppressed, and the armature coil 21 and the bearing member 232 are accordingly reduced.
Is also suppressed.

The shaft type linear motor LMq shown in FIG. 22 (sectional view) and FIG.
1, a member 293 having a circular shape in a front view is provided adjacent to each end. The member 293 has a plurality of ventilation openings 293 'for air intake and air discharge. The bearing member 232 of the mover 2 is provided on each member 293. The ventilation openings 293 'are formed at equal intervals along the outer periphery of the bearing member 232. The armature coil 21 is supported between the two members 293, and the two members 293 are fitted and supported by the casing 294.

In the linear motor LMq, the mover 2,
Accordingly, one member 29 is moved with the movement of the armature coil 21.
3 enters into the gap between the armature coil 21 and the field magnet 1 and the air flows through the other member 293 while removing heat from the armature coil 21 and the field magnet 1. 293 '. FIG.
Indicates the flow of air when the mover 2 moves in the direction of the arrow α in the figure.

Accordingly, the armature coil 21 is cooled from the inside, and the field magnet 1 is also cooled from its surface. Therefore, the temperature rise of the armature coil 21 and the field magnet 1 is suppressed, and the temperature rise of the bearing member 232 is also suppressed. The heat storage suppressing means for suppressing the temperature rise of the armature coil 21 and / or the field magnet 1 in each motor described above may be appropriately combined and adopted.

Next, the shaft type linear motor shown in FIGS. 24 to 29 will be described. The motor shown in FIGS. 24 to 29 is a type of motor that suppresses the influence of heat on the encoder sensor mounted on the armature coil 21. This type of shaft type linear motor suppresses the deterioration of the encoder sensor and the decrease in detection accuracy, and operates accurately under control by the encoder. As a result, a highly reliable shaft-type linear motor that operates with the intended operation can be obtained.

The linear motor LM shown in FIGS.
r, LMs, LMt, LMu, and LMv all have the armature coil 21 of the mover 2 housed in the casing 201. The linear motors LMr, LMs, and LMt shown in FIGS. 24 to 26 include the magnetic encoder 3, and the magnetic encoder scale 31 is installed outside the field magnet in parallel with the field magnet 1, and the armature The magnetic sensor 32 mounted on the coil 21 faces. Linear motors LMu, LM shown in FIGS. 28 and 29
v also includes the magnetic encoder 3, but the magnetic encoder scale 31 is formed on the field magnet 1 (in other words, formed on the shaft member 1a), and the armature coil 21 The magnetic sensor 32 mounted on the device faces.

In the linear motor LMr shown in FIG. 24, the magnetic sensor 3 is connected to the armature coil 21 via the casing 201 wall.
2 is mounted. The magnetic sensor 32 is mounted on a casing wall via a layered heat insulating member or heat insulating member H1 made of ceramic, resin, rubber, or the like as a heat transfer suppressing member. The shaft type linear motor LM shown in FIG.
In FIG. 5S, the magnetic sensor 32 is connected to the casing wall 201 via a layered heat dissipating member H2 made of a metal such as aluminum having a large heat dissipating effect as another heat transfer suppressing member and a heat insulating member H1 laminated thereon. It is installed in.
Here, the member H2 is provided with a heat dissipating fin, but may not be provided as long as the member has a desired heat dissipating effect. If sufficient heat dissipation is provided, the heat insulating member H1 may be omitted.

In the linear motor LMt shown in FIG. 26, as shown in FIG. 27, the magnetic sensor 32 has a peripheral surface other than the surface 321 facing the scale 31 as a heat transfer suppressing member.
It is covered with a heat insulating case H3 made of ceramic, resin, rubber or the like, and is mounted on the casing wall 201 via the heat insulating case. A heat dissipating member H2 as shown in FIG. 25 may be interposed between the heat insulating case H3 and the mover casing 201.

In the linear motor LMu shown in FIG. 28, the magnetic sensor 32 is connected to the casing wall 201 via the heat insulating member H1.
And a surface facing the encoder scale 31 of the sensor is covered with a layered heat insulating member H4 made of ceramic, resin, rubber, or the like. Heat insulating member H
A heat dissipating member H2 as shown in FIG. 25 may be interposed between 1 and the casing wall 201. The thickness of the portion of the heat insulating member H4 that covers the sensor detection end 32a is set to such an extent that the sensor 32 does not hinder reading of scale information. If the heat from the field magnet 1 does not cause deterioration of the sensor or deterioration of the detection accuracy, the sensor detection end 32a may be exposed.

In the linear motor LMv shown in FIG. 29, the magnetic sensor 32 is entirely mounted on a casing wall 201 of the mover 2 while being covered with a heat insulating case H5 made of ceramic, resin, rubber or the like. A heat radiating member H2 as shown in FIG. 25 is provided between the heat insulating case H5 and the casing wall 201.
May be interposed. The thickness of the portion of the heat insulating case H5 that covers the sensor detection end 32a is set to such an extent that reading of scale information by the sensor 32 is not hindered. If the heat from the field magnet 1 does not cause deterioration of the sensor or deterioration of the detection accuracy, the sensor detection end 32a may be exposed.

When the magnetic encoder is employed as described above, the heat transfer suppressing members H1, H2, H3,
H4 and H5 are preferably members made of a non-magnetic material. In particular, members H4 and H5 that cover the surface facing the scale 31 are used.
May be formed of a non-magnetic material. In the linear motors shown in FIGS. 24 to 29 described above, the armature coils 21
The influence of the heat generated by energization of the magnetic sensor 32 on the magnetic sensor 32 is suppressed by the heat transfer suppressing members (H1, H2, H3, H5).
8 and FIG. 29, the influence of the heat from the field magnet 1 on the magnetic sensor 32 is determined by the heat transfer suppressing members (H4, H4).
Since the suppression is performed in 5), the deterioration of the sensor 32 and the decrease in detection accuracy are suppressed, and these linear motors operate accurately under the control of the encoder. This results in a highly reliable shaft type linear motor that operates with the expected operation.

As described above, an optical encoder can be used as the encoder. When the optical encoder is used, the magnetic sensor 32 is an optical sensor, and the magnetic encoder scale 31 is the same as the optical encoder scale. do it. When the scale is formed on the field magnet 1 when the optical encoder is employed, the heat transfer suppressing member covering the detection end of the optical sensor is made of, for example, transparent or sufficiently transparent glass, resin, or the like. What should be done.

In the linear motor shown in FIG. 24 and the like, the encoder sensor is attached to the armature coil via the armature casing wall, but the encoder sensor is connected to the armature coil via an appropriate heat transfer suppressing member as described above. It may be attached directly. The structure of the linear motor when the encoder is provided is not limited to the structure shown in FIG. For example, any of the linear motor structures shown in FIGS. 1 to 23 described above or a linear motor structure in which these structures are appropriately combined can be adopted as long as there is no problem, and by doing so, the advantages described above can be combined. be able to.

FIGS. 34 and 35 show an image reading apparatus employing the shaft type linear motor LMb shown in FIG. 4 and a linear motor LMb 'having substantially the same structure as the motor. FIG. 34 is a schematic plan view of the image reading device. FIG. 2 is a schematic sectional view taken along line XX shown in FIG. The image reading device IR has a transparent platen glass GL for mounting a document on the top of the device. A cover CV is provided on the upper part of the platen glass GL so as to be openable and closable. In FIG. 34, illustration of the cover CV is omitted. Below the platen glass GL, in order to optically scan the original placed on the platen glass GL,
Two sliders SL1 and SL2 that can move in parallel with the platen glass GL and mount optical components are arranged.

The slider SL1 has a linear motor L by an arm member S2 also serving as a heat radiating member similar to the member S1 shown in FIG.
Mb of the slider SL
2 also has a linear motor L by an arm member S2 also serving as a heat radiating member.
Mb 'is connected to the mover 2'. These linear motors LMb and LMb 'are linear motors having substantially the same configuration. Each of the movers 2 and 2 ′ has a slider SL
1. It is externally fitted to a shaft-shaped field magnet 1 parallel to the platen glass GL in which the SL2 is moved, and can move along the field magnet 1. The field magnet 1 is supported by a support member (not shown) and is arranged at a fixed position. The field magnet 1 forms a common stator of the two linear motors LMb, LMb '. Each mover 2, 2 ′ has an armature coil 21, 21 ′ externally fitted to the stator 1.

When the armature coil 21 of the linear motor LMb is energized, the current flowing through the coil 21 and the magnetic field formed by the field magnet 1 interact to move the mover 2 having the armature coil 21 to the stator 1. Can be driven along. Similarly, when the armature coil 21 'of the linear motor LMb' is energized, the mover 2 'can be driven along the field magnet 1.

The slider SL1 has, as optical components, an illumination lamp LP for irradiating light on a document placed on the document table glass GL, and a slider SL for reflecting light from the document.
And a reflection mirror m1 for guiding the light to the second direction. A roller r is provided at the end of the slider SL1 opposite to the end to which the mover 2 is attached.
The roller r can roll on a plate-shaped guide member G arranged in parallel with the original table glass GL and the stator 1. As a result, the slider SL1 can move while maintaining its posture.

In the slider SL2, as optical components, reflection mirrors m2 and m3 for guiding the image light guided from the reflection mirror m1 on the slider SL1 to the reading unit 8.
Is installed. The slider SL2 is also the same as the slider SL.
1 has a roller r at the same position as that of the roller 1, and can move while maintaining the posture. The reading unit 8 includes a slider S
It has a lens 81 for forming an image of the image light guided from the reflection mirror m3 on L2, and an image pickup device (CCD) 82 for reading the formed image light. It should be noted that an image reading apparatus applicable to an analog copying machine can be provided by providing a reflecting means for guiding light from the mirror m3 to a photoconductor for image formation instead of the unit 8 as described above.

When reading an image of a document placed at a predetermined position on the platen glass GL, the illumination lamp LP on the slider SL1 is turned on, and the sliders SL1, SL
2 respectively connected to linear motors LMb, LM
By b ′, the original is scanned in parallel with the original platen glass GL. The slider SL1 and the slider SL2 are
For example, they are driven such that their speed ratio becomes 2: 1. At this time, light emitted from the illumination lamp LP and reflected by the document is reflected by mirrors m1, m2, and m3.
It is sequentially guided to the reading unit 8. In the reading unit 8, reflected light from the document is formed on the CCD 82 by the imaging lens 81, and the document image is sequentially read by the CCD 82.

In the image reading apparatus IR described above, a linear motor of the type shown in FIG. 4 is employed as the linear motor, but another linear motor as described above may be employed instead.

[0108]

As described above, according to the present invention, N
A field-shaped magnet having a shaft shape in which magnetic poles and magnetic poles of S-poles are alternately arranged, and an armature coil formed of a ring-shaped coil through which the field magnet penetrates; one of the field magnet and the armature coil Is a shaft type linear motor that is a movable element, and can provide a highly reliable shaft type linear motor that operates in a desired operation regardless of heat generated from an armature coil due to energization.

[Brief description of the drawings]

FIG. 1 is a sectional view of an example of a shaft type linear motor according to the present invention.

FIG. 2 is a sectional view of another example of the shaft type linear motor according to the present invention.

FIG. 3 is still another sectional view of the shaft-type linear motor according to the present invention.

FIG. 4 is a sectional view taken along line AA of FIG. 3;

FIG. 5 is a sectional view of still another example of the shaft type linear motor according to the present invention.

FIG. 6 is a sectional view taken along line BB of FIG. 5;

FIG. 7 is a sectional view of still another example of the shaft type linear motor according to the present invention.

FIG. 8 is a sectional view of still another example of the shaft type linear motor according to the present invention.

FIG. 9 is a sectional view taken along line CC of FIG. 8;

FIG. 10 is a sectional view of still another example of the shaft type linear motor according to the present invention.

FIG. 11 is a sectional view of still another example of the shaft type linear motor according to the present invention.

FIG. 12 is a side view of the linear motor shown in FIG.

FIG. 13 is a front view of the linear motor shown in FIG.

FIG. 14 is a side view of still another example of the shaft type linear motor according to the present invention.

FIG. 15 is a plan view of still another example of the shaft type linear motor according to the present invention.

FIG. 16 is a sectional view of still another example of the shaft type linear motor according to the present invention.

FIG. 17 is a sectional view of a field magnet in still another example of the shaft type linear motor according to the present invention.

FIG. 18 is a side view of still another example of the shaft type linear motor according to the present invention.

FIG. 19 is a cross-sectional view of a field magnet including a refrigerant circulation device in still another example of the shaft type linear motor according to the present invention.

FIG. 20 is a sectional view of a field magnet in still another example of the shaft type linear motor according to the present invention.

FIG. 21 is a sectional view of still another example of the shaft type linear motor according to the present invention.

FIG. 22 is a sectional view of still another example of the shaft type linear motor according to the present invention.

FIG. 23 is a front view of the motor shown in FIG. 22;

FIG. 24 is a sectional view of still another example of the shaft type linear motor according to the present invention.

FIG. 25 is a side view of still another example of the shaft type linear motor according to the present invention.

FIG. 26 is a side view of still another example of the shaft type linear motor according to the present invention.

FIG. 27 is a plan view of a magnetic sensor and a heat insulating case surrounding the magnetic sensor in the motor shown in FIG. 26;

FIG. 28 is a sectional view of still another example of the shaft type linear motor according to the present invention.

FIG. 29 is a side view of still another example of the shaft type linear motor according to the present invention.

30 is a block diagram illustrating an example of a circuit for controlling the energization of the linear motor illustrated in FIG. 1;

FIG. 31 is a circuit block diagram showing a motor drive control circuit portion in the circuit shown in FIG. 30 in more detail;

32 is a diagram showing the relationship between the detection magnetic pole of each Hall element and the timing of energizing each coil when the mover of the linear motor of FIG. 1 is driven to the left in FIG.

FIG. 33 is a diagram showing the relationship between the detection magnetic pole of each Hall element and the timing of energizing each coil when the mover of the linear motor in FIG. 1 is driven rightward in FIG.

FIG. 34 is a schematic plan view of an example of an image reading apparatus equipped with a linear motor of the type shown in FIG.

FIG. 35 is a schematic sectional view taken along line XX shown in FIG. 34;

[Explanation of symbols]

LMa, LMa ', LMb, LMb', LMc, LM
d, LMe, LMf, LMg, LMh, LMi, LM
j, LMk, LMm, LMn, LMo, LMp, LM
q, LMr, LMs, LMt, LMu, LMv Shaft type linear motor 1 Shaft shaped field magnet (stator) 1a Shaft member 2 Mover 21 Armature coils L _U1 , L _V1 , L _W1 , L _U2 , L _V2 and L _W2 coil 23 casing 231 vents 232 bearing member 3 magnetic encoder 31 magnetic encoder scale 32 magnetic sensor S driven member 23 'casing h _1, h _2, h ₃ Hall elements 2,2' movable element 21, 21 'armature coils 22, 22' frame 221 bearing 23 electric circuit board h _1, h _2, h ₃ Hall element (magneto-electric transducer) 23 'for some S1f heat radiation of the casing 24 radiating member 24f radiation fins S1 driven member Fin 25 Casing 220 Heat radiating member 26 Casing D1 Casing F1 Cooling air generator F1 f1 Propeller fan f1 d1 Exhaust hole D2 Flexible duct 27 Case 271 272 Vent hole 271a, 271b Outside air introduction guide fin 28 Bearing unit 28 232 ′ Bearing member HP Mover home position ST Mover start position EP Mover end point position FW1 Cooling device f2 Cooling fan F2 Cooling air generator D3 Duct FW2 Cooling device f3 Centrifugal blower F3 Cooling air generator FL Wind tunnel 11 Heat conductive material layer 12 Heat radiating fin 13 Back yoke Lq Refrigerant CL Refrigerant circulator P Pipe 14 Insulating material layer 291 Air reflector Member 291 ′ Concave portion of reflector member 292 Outer casing 293 Member circular in front view 293 ′ Vent opening for air intake and air discharge of member 293 294 Casing 20 Casing 201 Thing wall H1, H4 Heat insulating member (heat transfer suppressing member) H3 Heat releasing member (heat transfer suppressing member) H2, H5 Heat insulating case (heat transfer suppressing member) IR image reader GL Platen glass CV cover SL1, SL2 Optical Slider on which components are mounted S2 Arm member also serving as heat radiating member 2 'mover 21' armature coil LP illumination lamp m1, m2, m3 mirror 8 reading unit 81 lens 82 imaging device (CCD)

Claims (25)

[Claims] 1. A shaft-shaped field magnet in which N-poles and S-poles are alternately arranged, and an armature coil formed by a ring-shaped coil through which the field magnet penetrates. One of the armature coils is a shaft type linear motor having a mover, and heat storage for suppressing heat storage of at least one of the field magnet and the armature coil due to heat generated by energization of the armature coil. A shaft type linear motor, further comprising a suppression device. 2. The shaft type linear motor according to claim 1, wherein the heat storage suppressing device is a heat radiating device connected to the armature coil so as to conduct heat so as to dissipate heat generated from the armature coil. 3. The shaft type linear motor according to claim 2, wherein said heat radiating device includes a heat medium layer formed in contact with said armature coil. 4. A shaft type linear motor according to claim 3, wherein said heat radiating device includes a heat radiating member connected to said heat medium layer. 5. The shaft type linear motor according to claim 2, wherein said heat radiating device includes a heat radiating member connected to said armature coil. 6. A shaft type linear motor according to claim 4, wherein said heat radiating member includes a heat radiating fin. 7. The armature coil is a mover, the shaft-shaped field magnet is a stator, and a driven body is connected to the armature coil, at least a part of the driven body. 7. The shaft type linear motor according to claim 4, wherein the shaft also functions as the heat radiating member. 8. A shaft type linear motor according to claim 7, wherein said driven body is a slider on which an optical component for reading a document image in an image reading device is mounted. 9. A shaft type linear motor according to claim 1, wherein said heat storage suppressing device is a cooling device provided for said armature coil. 10. The shaft type linear motor according to claim 9, wherein said cooling device includes a cooling air generator for blowing cooling air to said armature coil. 11. The shaft type linear motor according to claim 10, wherein said cooling device includes a coil cooling ventilation duct for flowing and discharging an air flow from said cooling air generator along the periphery of said armature coil. 12. The armature coil is a mover, and the shaft-shaped field magnet is a stator. The cooling device surrounds the armature coil and extends along the stator. 10. The shaft type linear motor according to claim 9, further comprising a case capable of reciprocating with the coil, wherein the case is provided with a ventilation hole for allowing outside air to pass through the case as the armature coil moves. 13. An armature coil is used as a mover, and the shaft-shaped field magnet is used as a stator. The heat storage suppressing device includes a bearing unit that can reciprocate along the stator. 2. The shaft type linear motor according to claim 1, wherein the bearing unit supports the armature coil so as to be exposed to the outside. 14. An armature coil as a mover and said shaft-shaped field magnet as a stator, wherein said heat storage suppressing device is located at a position facing a movement passage of said armature coil and said The shaft according to claim 1, wherein the cooling device is capable of cooling the armature coil at the stop position and a portion of the field magnet corresponding to the armature coil stop position at a position corresponding to at least one of the positions where the coil is stopped. Type linear motor. 15. The cooling air generator according to claim 14, wherein the cooling device is capable of blowing cooling air to the armature coil at the stop position and a portion of the field magnet corresponding to the armature coil stop position. Shaft type linear motor. 16. The shaft type linear motor according to claim 1, wherein the heat storage suppressing device is a heat radiating device connected to the field magnet so as to be able to conduct heat so as to suppress heat storage in the field magnet. 17. The heat radiating device includes a heat conductive material layer coated on an outer peripheral surface of the field magnet.
6. The shaft type linear motor according to 6. 18. A shaft type linear motor according to claim 1, wherein said heat storage suppressing device includes a heat insulating material layer coated on an outer peripheral surface of said field magnet. 19. The shaft type linear motor according to claim 1, wherein said heat storage suppressing device is a cooling device provided for said field magnet. 20. The shaft type linear motor according to claim 19, wherein said cooling device circulates a refrigerant through a cooling medium passage formed in said field magnet. 21. The armature so that the cooling device generates an eddy current of air in a region above the field magnet adjacent to the end of the armature coil with the relative movement of the field magnet and the armature coil. 20. The shaft type linear motor according to claim 19, further comprising an air reflector member provided adjacent to each end of the coil. 22. The heat storage suppressing device is a cooling device provided for the armature coil and the field magnet, and the cooling device is provided with the relative movement of the field magnet and the armature coil. 2. A member having a ventilation opening for air intake and exhaust provided adjacent to each end of the armature coil so as to allow air to flow through a gap between the armature coil and the field magnet. Shaft type linear motor. 23. A shaft-shaped field magnet in which N-poles and S-poles are alternately arranged, and an armature coil formed by a ring-shaped coil through which the field magnet penetrates.
One of the field magnet and the armature coil is a shaft type linear motor in which a mover is provided, and an encoder for controlling operation is attached and an encoder sensor for reading scale information of the encoder is provided to the sensor. A shaft-type linear motor mounted on the armature coil via a member that suppresses heat transfer from the armature coil. 24. A shaft-shaped field magnet in which N-poles and S-poles are alternately arranged, and an armature coil formed by a ring-shaped coil through which the field magnet penetrates.
One of the field magnet and the armature coil is a shaft type linear motor in which a mover is provided, and an encoder for operation control is provided, and a scale of the encoder is formed on the field magnet. A sensor for reading scale information of the encoder is mounted on the armature coil, and the sensor transfers heat from the field magnet to the sensor in a state where a detection end for reading the scale information can read scale information. Shaft type linear motor that is covered with a member that suppresses noise. 25. A shaft type linear motor according to claim 24, wherein said sensor is mounted on said armature coil via a member for suppressing heat transfer from said armature coil to said sensor.