JPH09222318A - Position detection mechanism of linear motor running shaft - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control and adjust a position detection mechanism easily even if the running stroke of a running shaft becomes long in the position detection mechanism of a linear motor running shaft. SOLUTION: A linear motor running shaft for moving a traveling part (running table 72) along a running shaft (running rail 71) by a linear motor drive mechanism has at least a wire 2 that is extended with a specific tension between the traveling part (running table 72) and a fixed side (stopper 73) of the running shaft (running rail 71) and a rotary encoder 3 for detecting the amount of relative displacement to the wire 3, thus constituting a position detection mechanism 1. The amount of travel along the running shaft (running rail 71) of the traveling part (running table 72) is detected by a rotary encoder 3, thus detecting a position.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a position detecting mechanism for detecting the position of a traveling shaft driven by a linear motor.

[0002]

2. Description of the Related Art Traveling axes are used as moving means for expanding the operating range of mechanical devices such as robots and machine tools.
A linear motor is known as this drive source. Generally, a linny motor is provided with a fixed magnetic field generating means and a moving magnetic field generating means, and is driven by mutual attraction and repulsion of magnetic force. Since this linear motor does not have a position detecting means on the mechanism, it is necessary to provide some position detecting means for controlling the position of the traveling shaft.

As a position detecting means provided in a linear motor, a position detecting device in which a linear scale or a rack and pinion mechanism and a rotary encoder are combined has been conventionally known. FIG. 15 is a schematic diagram for explaining a position detecting means provided in a conventional linear motor. In FIG. 15, the linear motor includes, for example, a fixed magnetic field portion 74 formed by arranging a plurality of magnets, and a movable magnetic field portion 75 movably installed along the fixed magnetic field portion 74. A traveling table 72 provided with a movable magnetic field portion 75 is configured to move on a traveling rail 71 arranged along 74 while being supported by a traveling block 76.

A combination of the linear scale mechanism 8 or the rack and pinion mechanism 9 and the rotary encoder 3 is used as means for detecting the position of the traveling table 72 of the linear motor. Note that FIG. 15 shows a diagram in which both position detecting means are provided in one linear motor for convenience of explanation.

In the linear scale mechanism 8, a scale material 81 such as a metal scale is arranged along the traveling rail 71, and the detector 82 provided on the traveling table 72 side detects the scale material 81 to detect the position. ing. Further, in the mechanism in which the rack and pinion mechanism 9 and the rotary encoder 3 are combined, the rack 9 is moved along the traveling rail 71.
The rack and pinion mechanism 9 is constructed by disposing the pinion 1 on the traveling table 72 side and engaging with the rack 91, and the rotary encoder 3 detects the amount of rotation of the pinion 92 to detect the position.

[0006]

In the conventional position detecting mechanism for a linear motor, when the traveling stroke of the traveling shaft becomes longer, the mechanism main body for detecting the position becomes longer accordingly, so that the position detecting mechanism can be managed and adjusted. There is a problem that it becomes necessary.

For example, in the case of a linear scale,
Since the scale member such as a metal scale is integrally formed, a plurality of unit units each having a unit length are combined to form a stroke of a predetermined length. It cannot be divided and transported to the installation position and combined. Further, if the scale member is divided, it is necessary to manage the joint error between the scale members within the predetermined error in the connecting portion of the divided units, which is a difficult task. In addition, it is necessary to manage the gap so that the gap between the scale member and the measuring head of the detector is a predetermined distance, which requires troublesome adjustment.

Further, when the scale member is contaminated with oil, dust, etc., the accuracy of the position information may deteriorate. In addition, in a position detection mechanism that combines a rack and pinion mechanism and a pulse encoder, when unit units are combined to form a traveling shaft with a predetermined stroke, multiple racks are added to the rack for installation. Sometimes it is necessary to control the pitch of the seams.

Further, since the rack and pinion mechanism has a backlash due to its mechanism, it is necessary to deal with a detection error due to the backlash, and if dust or the like adheres to the rack, an error in position detection occurs. There is a risk. In addition, the lubrication between the rack and pinion needs to be managed on a regular basis. In addition, in any position detection mechanism that is a combination of a linear scale, a rack and pinion mechanism, and a pulse encoder, the scale member and the rack to be arranged become long and the price becomes expensive due to the lengthening of the stroke. There is.

In view of the above, the present invention solves the above-mentioned problems of the prior art, and enables the management and adjustment of the position detection mechanism to be facilitated even when the traveling stroke of the traveling shaft becomes long. An object is to provide a position detection mechanism.

[0011]

According to the present invention, in a linear motor traveling shaft for moving a traveling portion along a traveling shaft by a linear motor drive mechanism, a predetermined tension is at least provided between the traveling portion and the fixed side of the traveling shaft. A position detection mechanism is configured by including a wire stretched with a wire and a rotary encoder that detects the relative displacement amount of the wire, and the rotary encoder detects the amount of movement along the traveling axis of the moving portion to detect the position. It can be carried out.

The linear motor drive mechanism is provided with a fixed side arranged along the traveling axis and a moving section moving along the traveling axis, and attracts or repels the magnetic force generated between the fixed magnetic field and the moving magnetic field. The linear motor drive shaft is a drive mechanism that drives the moving unit, and the linear motor drive mechanism moves the moving unit to move the traveling table or the like.

The position detecting mechanism includes a wire stretched with a predetermined tension between the moving part and the fixed side of the traveling shaft, and a rotary encoder for detecting a relative displacement amount of the wire.
When the moving unit moves, the wire itself moves or the moving unit moves with respect to the fixed wire. This movement amount corresponds to the movement amount of the moving unit. The rotary encoder is a detection unit that detects the relative movement amount of the wire and the rotary encoder, and detects the movement amount of the wire itself or the movement amount of the moving portion with respect to the wire. Therefore, the amount of movement of the moving unit can be obtained from the amount of detection of the rotary encoder.

The wire is stretched at least between the moving portion and the fixed side of the traveling shaft, and may be stretched between the fixed ends on both sides of the traveling shaft via the moving portion. Further, the mechanism for applying tension to the wire can be a wire winding mechanism, and can be configured by a wire drum to which torque in one direction is applied by a winding spring.

The mounting position of the wire is, for example, such that one end of the wire is fixed to the moving part and the other end of the wire is mounted to a rotary encoder fixed to the fixed side of the traveling shaft, or one end of the wire is fixed to the traveling shaft. Fixed to the rotary encoder with the other end of the wire fixed to the moving part, or with one end of the wire fixed to the fixed side of the traveling shaft and the other end of the wire fixed to the fixed side of the traveling shaft. It is attached to the encoder so that the middle part of the wire passes through the moving part, or one end of the wire is fixed to the moving part and the other end of the wire is fixed to one fixed side of the traveling shaft via a rotary encoder. A rotary structure in which the wire is fixed to the other fixed side, or one end of the wire is fixed to one of the moving parts and the other end of the wire is fixed to one fixed side of the traveling shaft. The first rotary encoder and the traveling shaft, which are configured to be fixed to the other of the moving units via an encoder, or one end of the wire is fixed to one of the moving units and the other end of the wire is fixed to one fixed side of the traveling shaft. The second rotary encoder fixed to the other fixed side of the moving part is fixed to the other side of the moving part, or one end of the wire is fixed to one fixed side of the traveling shaft, and the rotary encoder provided in the moving part is fixed. It can be configured to be fixed to the other fixed side of the traveling shaft via the.

Further, in the structure in which one end of the wire is fixed to one fixed side of the traveling shaft and is fixed to the other fixed side of the traveling shaft via the rotary encoder provided in the moving portion, at least one wire is attached to the rotary encoder. By winding the wire, movement of the wire can be transmitted to the rotary encoder, and by pressing the wire to the rotary encoder, tension can be applied to the wire and movement of the wire can be transmitted to the rotary encoder.

[0017]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a schematic perspective view illustrating a first embodiment of a position detecting mechanism for a linear motor traveling shaft according to the present invention, and FIG. 2 is a plan view for explaining a mechanism arrangement of the first embodiment. is there.

In FIGS. 1 and 2, the linear motor traveling shaft includes a traveling rail 71 having an end fixed by a stopper 73 and a traveling table 72 movably supported by a traveling block 76 along the traveling rail 71. The linear motor 7 includes the fixed magnetic field portion 74 arranged along the traveling rail 71 and the moving magnetic field portion 75 provided on the traveling table 72. The fixed magnetic field portion 74 can be formed by connecting a plurality of magnets, for example,
The moving magnetic field portion 75 can be formed by a coil. Then, the traveling table 72 is moved using the attractive force or repulsive force formed by the magnetic fields formed by the fixed magnetic field portion 74 and the moving magnetic field portion 75. Since the mechanism of the linear motor and its operation are well known, detailed description thereof will be omitted here.

On the linear motor traveling shaft, the position detecting mechanism for detecting the position of the traveling table 72 is provided with the wire 2 and the rotary encoder 3. One end of the wire 2 is fixed to the traveling table 72 which is a moving portion, The other end is attached to the rotary encoder 3 fixed to the stopper 73 which is the fixed side of the traveling shaft, and the wire 2 is wound by the wire winder 4 (not shown in FIG. 1) provided on the fixed side of the traveling shaft. The tension is applied by pulling the rotary encoder 3 side. The wire winding machine 4 winds the wire 2 with a predetermined torque, for example, and applies a predetermined tension to the unwound wire 2. In addition, the rotary encoder 3
Detects the relative displacement with respect to the wire 2.

Therefore, the wire 2 is attached to the traveling table 72.
It is stretched between the rotary encoder 3 and the rotary encoder 3, and when the traveling table 72 moves, it is unwound from the wire winder 4 or wound by the wire winder 4 in accordance with the movement amount. The unwound wire 2 or the wound wire 2 passes through the rotary encoder 3. Therefore, the unwound amount or the wound amount is determined by the rotary encoder 3.
Is measured by Since the wire 2 is always kept in a stretched state by the wire winder 4, the moving amount of the traveling table 72 and the relative displacement amount of the wire 2 with respect to the rotary encoder 3 correspond to each other in a one-to-one relationship. Therefore,
When the relative displacement amount with respect to the wire 2 is detected by the rotary encoder 3, the movement amount of the traveling table 72 can be detected from the detected displacement amount, and the position of the traveling table 72 on the traveling axis can be detected. it can.

The amount of movement of the traveling table 72 can be detected by the amount of movement of the wire 2, and the laying of the wire 2 can be performed without being affected by the joint of the traveling rail and the fixed magnetic field portion 74. .

Next, the second linear motor traveling shaft of the present invention will be described.
An embodiment will be described. FIG. 3 is a schematic perspective view for explaining the second embodiment of the present invention, and FIG. 4 is a plan view for explaining the mechanism arrangement of the second embodiment.
In FIGS. 3 and 4, the configuration of the linear motor traveling shaft is the same as that shown in the second embodiment of FIGS. 1 and 2, and the description thereof is omitted here.

In the linear motor traveling shaft, the position detecting mechanism for detecting the position of the traveling table 72 includes the wire 2 and the rotary encoder 3, and one end of the wire 2 is fixed to the stopper 73 which is the fixed side of the traveling shaft. Then, the other end of the wire 2 is attached to the rotary encoder 3 fixed to the traveling table 72 which is a moving part, and the wire 2 is pulled by the wire winding machine 4 provided on the traveling table 72 toward the rotary encoder 3 side. It gives tension. Further, the rotary encoder 3 detects the amount of relative displacement with the wire 2.

In the position detecting mechanism of the first embodiment, the rotary encoder 3 is installed on the fixed side stopper 73, whereas the position detecting mechanism of the second embodiment has the rotary encoder 3. Is different in that it is installed on the traveling table 72 side. The wires 2, the rotary encoder 3, and the wire winder 4 may have the same configurations as those used in the first embodiment.

The operation of the position detecting mechanism of the second embodiment is almost the same as that of the position detecting mechanism of the first embodiment. When the traveling table 72 moves, the wire 2 moves according to this movement. Since the moving amount of the traveling table 72 and the relative displacement amount of the wire 2 with respect to the rotary encoder 3 correspond to each other, when the relative displacement amount with the wire 2 is detected by the rotary encoder 3, the traveling table 72 moves from the detected displacement amount. Quantity can be detected,
Further, the position of the traveling table 72 on the traveling axis can be detected. Further, similarly to the first embodiment, the movement amount of the traveling table 72 can be detected by the movement amount of the wire 2, and the laying of the wire 2 is influenced by the joint portion of the traveling rail and the fixed magnetic field portion 74. Can be done without

The detection signal detected by the rotary encoder 3 can be taken out of the traveling axis through the same route as the supply line to the moving magnetic field section 75. Next, a third embodiment of the linear motor traveling shaft of the present invention will be described. FIG. 5 is a plan view for explaining the mechanism arrangement of the third embodiment.

In FIG. 5, the configuration of the linear motor traveling shaft is the same as that shown in the first and second embodiments, and the description thereof is omitted here. In the linear motor traveling shaft, the position detecting mechanism for detecting the position of the traveling table 72 includes a wire 2 and a rotary encoder 3, and one end of the wire 2 is a stopper 7 that is a fixed side of the traveling shaft.
3, the other end of the wire 2 is attached to the rotary encoder 3 which is fixed to the stopper 73 on the same side, and the intermediate portion of the wire 2 passes through the traveling table 72 which is the moving portion. The wire winding machine 4 provided pulls the wire 2 toward the rotary encoder 3 to apply tension. The pulley 51 is attached to the traveling table 72, and the intermediate portion of the wire 2 is hung on the pulley 51 to stretch the wire between the traveling table 72 and the stopper 73. Further, the rotary encoder 3 detects the amount of relative displacement with the wire 2.

In the position detecting mechanism of the first and second embodiments, the wire 2 is stretched at one place between the traveling table 72 and the stopper 73, whereas the position detecting mechanism of the third embodiment is arranged. The position detection mechanism of the embodiment is different in that the wire 2 is stretched at two positions between the traveling table 72 and the stopper 73. The wires 2, the rotary encoder 3, and the wire winder 4 may have the same configurations as those used in the first and second embodiments.

In the position detecting mechanism of the third embodiment, when the traveling table 72 moves and the pulley 51 moves, the wire 2 moves in accordance with this movement. Since one end of the wire 2 is fixed to the stopper 73, the wire winding machine 4 at the other end of the wire 2 feeds or winds a wire having a length twice the moving amount of the traveling table 72. Therefore, when the relative displacement amount with respect to the wire 2 is detected by the rotary encoder 3, the detected displacement amount is twice the movement amount of the traveling table 72. Further, the position of the traveling table 72 on the traveling axis can be detected. Therefore,
The measurement amount can be doubled with respect to the displacement amount, and the measurement accuracy can be improved. Further, similarly to the first and second embodiments, the movement amount of the traveling table 72 can be detected by the movement amount of the wire 2, and the laying of the wire 2 is performed at the joint portion of the traveling rail or the fixed magnetic field portion 74. It can be done without being affected.

Next, the fourth embodiment of the linear motor traveling shaft of the present invention
An embodiment will be described. FIG. 6 is a plan view for explaining the mechanism arrangement of the fourth embodiment. In FIG. 6, the configuration of the linear motor traveling shaft is as follows:
Since it is the same as that shown in the embodiment, description thereof will be omitted here.

The position detecting mechanism for detecting the position of the traveling table 72 on the traveling axis of the linear motor comprises a wire 2 and a rotary encoder 3. One end of the wire 2 is fixed to the traveling table 72, and the wire 2 is fixed. The other end is fixed to the stopper on the other fixed side via the rotary encoder 3 fixed to the stopper on the one fixed side of the traveling shaft, and the wire winding machine 4 provided on the stopper on the other fixed side It pulls 2 to give tension. The intermediate portion of the wire 2 is hung on the rotary encoder 3 fixed to one stopper on the fixed side, so that the wire is stretched between the traveling table 72 and the stopper. Further, the rotary encoder 3 detects the amount of relative displacement with the wire 2.

In the position detecting mechanism of the first and second embodiments, the wire 2 is stretched at one position between the traveling table 72 and the stopper 73, whereas the position detecting mechanism of the fourth embodiment is arranged. The position detection mechanism is different in that the wire 2 is stretched between the traveling table and the stopper via the rotary encoder 3 and in two places between the stoppers. The wires 2, the rotary encoder 3, and the wire winder 4 may have the same configurations as those used in the first, second, and third embodiments.

In the position detecting mechanism of the fourth embodiment, the wire 2 stretched between both stoppers is given a tension by the winding by the wire winding machine 4, and further,
Tension is applied to the wire 2 stretched between the traveling table 72 and the stopper via the rotary encoder 3.

When the traveling table 72 moves, the wire 2
Is fed from the wire winder 4 or wound via the rotary encoder 3. At this time,
The rotary encoder 3 detects the amount of movement of the wire 2 and further detects the position of the traveling table 72 on the traveling axis. Further, similarly to the first, second, and third embodiments, the movement amount of the traveling table 72 can be detected by the movement amount of the wire 2, and the laying of the wire 2 is performed by connecting the traveling rail and the fixed magnetic field portion 74. It can be done without being affected by parts.

Next, the fifth embodiment of the linear motor traveling shaft of the present invention will be described.
An embodiment will be described. FIG. 7 is a plan view for explaining the mechanism arrangement of the fifth embodiment. In FIG. 7, the configuration of the linear motor traveling shaft is the same as that shown in the first to fourth embodiments, and the description thereof is omitted here.

The position detection mechanism for detecting the position of the traveling table 72 on the linear motor traveling shaft is provided with the wire 2 and the rotary encoder 3. One end of the wire 2 is fixed to the traveling table 72 and the other of the wires 2 is fixed. The end is fixed to the other side of the traveling table 72 via the rotary encoder 3 fixed to one fixed side stopper of the traveling shaft, and further to the other side of the traveling table 72 via the pulley 52 attached to the other fixed side stopper. The wire 2 is pulled by a wire winder (not shown) provided or a pulling device (not shown) attached to the rotary encoder 3 or the pulley 52 to apply tension. The wire 2 is stretched between the traveling table 72 and the stopper by hooking one middle part of the wire 2 on the rotary encoder 3 and hooking the other middle part of the wire 2 on the pulley 52. Further, the rotary encoder 3 detects the amount of relative displacement with the wire 2.

In the position detecting mechanism of the first and second embodiments, the wire 2 is stretched at one position between the traveling table 72 and the stopper 73, while the fifth embodiment is arranged. The position detecting mechanism of the embodiment is different in that the wire 2 is stretched between the traveling table and the stopper via the rotary encoder 3 and the pulley 52 and in three places between the stoppers. In addition, the wire 2, the rotary encoder 3,
The individual configurations of the wire winder 4 can be the same as those used in the first to fourth embodiments.

In the position detecting mechanism of the fifth embodiment, when tension is applied by the wire winding machine, the tension is applied between both stoppers and between the stopper and the traveling table by the winding torque of the wire winding machine. The wire 2 is tensioned. When the traveling table 72 moves, the wire 2 is stretched or wound from the wire winding machine via the rotary encoder 3 and the pulley 52 while being stretched.

When the tension is applied by the traction device, the rotary encoder 3 and / or the pulley 5 are used.
The wire 2 is tensioned by pulling the wire 2 to both outer sides in FIG. 7 by a pulling device (not shown). Then, when the traveling table 72 moves, the wire 2 moves while drawing a track-shaped trajectory via the rotary encoder 3 and the pulley 52 while being stretched.

At this time, the rotary encoder 3 detects the amount of movement of the wire 2 and further detects the position of the traveling table 72 on the traveling axis. Further, similarly to the first to fourth embodiments, the movement amount of the traveling table 72 can be detected by the movement amount of the wire 2, and the laying of the wire 2 affects the traveling rail and the joint portion of the fixed magnetic field portion. Can be done without being done.

The pulling device for applying tension to the wire is
It can be provided on either or both sides of the rotary encoder side or the pulley side, and when it is provided on either side, the other side is fixed to the traveling shaft. Next, a sixth embodiment of the linear motor traveling shaft of the present invention will be described. FIG. 8 is a plan view for explaining the mechanism arrangement of the sixth embodiment.

In FIG. 8, the structure of the linear motor traveling shaft is the same as that shown in the first to fifth embodiments, and the description thereof is omitted here. The position detection mechanism that detects the position of the travel table 72 on the linear motor travel shaft includes the wire 2 and the rotary encoder 3. One end of the wire 2 is fixed to the travel table 72 and the other end of the wire 2 travels. The first rotary encoder 31 fixed to one stopper on one fixed side of the shaft and the first rotary encoder 32 attached to the other stopper on the other fixed side are fixed to the other traveling table 72. A wire winder (not shown) provided at 72 or a pulling device (not shown) attached to the first and second rotary encoders 31 and 32 pulls the wire 2 to apply tension. . The wire 2 is stretched between the traveling table 72 and the stopper by hooking one intermediate portion of the wire 2 on the first rotary encoder 31 and hooking the other intermediate portion of the wire 2 on the second rotary encoder 32. Also,
The rotary encoder 3 detects the amount of relative displacement with the wire 2.

The position detecting mechanism of the sixth embodiment is the first
The wire 5 is stretched between the traveling table and the stopper and between the stoppers via the rotary encoder 31 and the second rotary encoder 32.
The embodiments are common. The wires 2, the rotary encoder 3, and the wire winder 4 may have the same configurations as those used in the first to fifth embodiments.

The means for applying tension in the position detecting mechanism of the sixth embodiment is common to that of the fifth embodiment, and therefore its explanation is omitted here. And the traveling table 7
When the wire 2 moves, the wire 2 moves while drawing a track-shaped locus via the first rotary encoder 31 and the second rotary encoder 32 while being stretched.

At this time, the first rotary encoder 3
Both the first and second rotary encoders 32 can detect the movement amount of the same wire 2 and can obtain the movement amount of the wire 2 by the average value of the two measured values. Further, the position of the traveling table 72 on the traveling axis is detected based on the measured movement amount. In this embodiment, the measurement error can be reduced by adopting a configuration in which the moving amount of the wire 2 is measured by two rotary encoders and an average value is obtained.

Further, similarly to the first to fifth embodiments, the moving amount of the traveling table 72 can be detected by the moving amount of the wire 2, and the laying of the wire 2 is performed by connecting the traveling rail and the fixed magnetic field portion. It can be done without being affected by parts.

Next, the seventh embodiment of the linear motor traveling shaft of the present invention will be described.
An embodiment will be described. FIG. 9 is a plan view for explaining the mechanism arrangement of the seventh embodiment, FIG. 11 is a perspective view including a partial cross section for explaining the seventh embodiment, and FIG. It is a figure for demonstrating the wire state of 7th Embodiment. In FIG. 9, the configuration of the linear motor traveling shaft is the same as that shown in the first to sixth embodiments, and the description thereof is omitted here.

The position detecting mechanism for detecting the position of the traveling table 72 on the linear motor traveling shaft is equipped with the wire 2 and the rotary encoder 3 and is shown in FIGS.
As shown in FIG. 1, one end of the wire 2 is fixed to a stopper on one fixed side of the traveling shaft, and the wire 2 is wound around the rotary encoder 3 provided on the traveling table 72 as shown in FIG. The other end of the wire 2 is fixed to the other fixed side stopper of the traveling shaft, and the wire 2 is wound by a wire winder (not shown) provided on the fixed side stopper
Is tow and give tension. Further, the rotary encoder 3 detects the amount of relative displacement with the wire 2. The individual configurations of the wire 2, the rotary encoder 3, and the wire winder can be the same as those used in the first to sixth embodiments.

In the position detecting mechanism of the seventh embodiment, when the traveling table 72 moves, the wire 2 moves while winding the rotating portion of the rotary encoder 3 while being stretched, and is fed from the wire winding machine. Or, it is wound up.

At this time, the rotary encoder 3 detects the amount of movement of the wire 2 and further detects the position of the traveling table 72 on the traveling axis. Further, similarly to the first to sixth embodiments, the movement amount of the traveling table 72 can be detected by the movement amount of the wire 2, and the laying of the wire 2 affects the joint portion of the traveling rail and the fixed magnetic field portion. Can be done without being done.

Next, the eighth embodiment of the linear motor traveling shaft of the present invention
An embodiment will be described. FIG. 10 is a plan view for explaining the mechanism arrangement of the eighth embodiment, and FIG.
Is a perspective view including a partial cross section for explaining the eighth embodiment, and FIG. 12 is a view for explaining a wire state of the eighth embodiment. In FIG. 10, the configuration of the linear motor traveling shaft is the same as that shown in the first to seventh embodiments, and the description thereof is omitted here.

On the linear motor traveling shaft, the position detecting mechanism for detecting the position of the traveling table 72 is equipped with the wire 2 and the rotary encoder 3. As shown in FIG. 10 and FIG. It is fixed to one stopper on the fixed side of the shaft, the wire 2 is pressed against the rotary encoder 3 provided on the traveling table 72 as shown in FIG. 12B, and the other end of the wire 2 is fixed to the other fixed side of the traveling shaft. In this configuration, the wire 2 is pulled by a wire winding machine (not shown) provided on the fixed stopper to give tension. Further, the rotary encoder 3 detects the amount of relative displacement with the wire 2.
The wires 2, the rotary encoder 3, and the wire winding machine may have the same configurations as those used in the first to seventh embodiments.

In the position detecting mechanism of the eighth embodiment, when the traveling table 72 is moved, the wire 2 is moved while pushing the rotating portion of the rotary encoder 3 in a stretched state, and is fed from the wire winding machine. Alternatively, winding is performed.

At this time, the rotary encoder 3 rotates according to the movement of the wire 2 to detect the movement amount, and further detects the position of the traveling table 72 on the traveling axis. In addition, as in the first to seventh embodiments, the traveling table 72
The amount of movement of the wire 2 can be detected by the amount of movement of the wire 2, and the wire 2 can be laid without being affected by the running rail or the joint portion of the fixed magnetic field portion.

In the first to eighth embodiments, the rotary encoder can be constituted by, for example, a pulse coder, and in this case, the displacement amount is output by the number of pulses. Next, the configurations of the wire winder and the rotary encoder applicable to the above-described embodiment will be described with reference to FIGS. 13 and 14.

FIG. 13 shows a structure in which the rotary encoder 3 and the wire winding machine 4 are combined. Wire winder 4
Is a wire drum 4 for winding the wire 2 in the case 41.
3 and a winding spring 4 for applying a torque to the wiregram 43
2 are arranged coaxially, and the shaft is rotatably supported by a bearing 44 and a bearing nut 45. The wire 2 fed from the wire drum 43 is transferred to the pulley 47.
Etc. is taken out through the guide. The take-up spring 42 applies torque in the direction in which the wire 2 is wound around the wire drum 43.

The shaft of the wire winder 4 and the shaft of the rotary encoder 3 are connected via an Oldham coupling 46 or the like, and the rotation of the wire drum 43 is controlled by the rotary encoder 3.
Is transmitted to The rotary encoder 3 detects the amount of movement of the wire 2 by measuring the amount of rotation of the shaft of the wire winder 4.

Further, FIG. 14 shows a structure in which the rotary encoder 3 and the wire winding machine 4 are separated. The wire winding machine 4 has a wire drum 43 that winds the wire 2 and a winding spring 42 that applies a torque to the wiregram 43, which are coaxially arranged in the second case 412.
It is supported against rotation. On the other hand, in the first case 411, the pulley 5 is rotatably supported by the bearing 44 and the bearing nut 45, and the Oldham joint 46
Is connected to the rotary encoder 3 via.

The wire 2 unwound from the wire drum 43 of the wire winder 4 is taken out toward the traveling table or the like via the pulley 5. The take-up spring 42 applies torque in the direction in which the wire 2 is wound around the wire drum 43.

When the wire 2 is wound around or reeled out by the wire drum 43 of the wire winder 4, the pulley 5 rotates as the wire 2 moves. The rotary encoder 3 detects the amount of movement of the wire 2 by measuring the amount of rotation of the pulley 5.

According to the embodiment of the present invention, even when the stroke of the linear motor traveling shaft is lengthened, it can be dealt with only by increasing the length of the wire, and the increase in price can be suppressed. . Further, even when the traveling shaft is configured by connecting the units, it is not necessary to adjust the position between the unit and the position detection mechanism at the location where the traveling shaft is installed, and the man-hours for installation can be reduced. .

[0062]

As described above, according to the present invention,
It is possible to provide a position detection mechanism for a linear motor traveling shaft that can easily manage and adjust the position detection mechanism even when the traveling stroke of the traveling shaft becomes long.

[Brief description of drawings]

FIG. 1 is a schematic perspective view illustrating a first embodiment of a position detection mechanism for a linear motor traveling shaft of the present invention.

FIG. 2 is a plan view for explaining the mechanism arrangement of the first embodiment of the present invention.

FIG. 3 is a schematic perspective view illustrating a second embodiment of the present invention.

FIG. 4 is a plan view for explaining the mechanism arrangement of the second embodiment of the present invention.

FIG. 5 is a plan view for explaining a mechanism arrangement according to a third embodiment of the present invention.

FIG. 6 is a plan view for explaining a mechanism arrangement according to a fourth embodiment of the present invention.

FIG. 7 is a plan view for explaining the mechanism arrangement of the fifth embodiment of the present invention.

FIG. 8 is a plan view for explaining the mechanism arrangement of the sixth embodiment of the present invention.

FIG. 9 is a plan view for explaining the mechanism arrangement of the seventh embodiment of the present invention.

FIG. 10 is a plan view for explaining a mechanism arrangement according to an eighth embodiment of the present invention.

FIG. 11 is a perspective view including a partial cross section for explaining seventh and eighth embodiments of the present invention.

FIG. 12 is a diagram for explaining wire states of the seventh and eighth embodiments of the present invention.

FIG. 13 is a configuration diagram of a wire winder and a rotary encoder.

FIG. 14 is a configuration diagram of a wire winder and a rotary encoder.

FIG. 15 is a schematic diagram for explaining position detecting means provided in a conventional linear motor.

[Explanation of symbols]

 1 Position Detection Mechanism 2 Wires 3, 31, 32 Rotary Encoder 4 Wire Winder 5, 51, 52, 53 Pulley 7 Linear Motor 8 Linear Scale Mechanism 41, 411, 412 Case 42 Winding Spring 43 Wire Drum 44 Bearing 45 Bearing Nut 46 Oldham coupling 71 Traveling rail 72 Traveling table 73 Stopper 74 Fixed magnetic field part 75 Moving magnetic field part 76 Traveling block

Claims (12)

[Claims] 1. A linear motor traveling shaft for moving a moving portion along a traveling shaft by a linear motor drive mechanism, and a wire stretched with a predetermined tension between at least the moving portion and a fixed side of the traveling shaft, A linear encoder for detecting a relative displacement amount with respect to the wire, wherein the rotary encoder detects the amount of movement of the moving portion along the traveling axis to perform position detection. . 2. The position detecting mechanism for a linear motor traveling shaft according to claim 1, wherein the tension is applied by a wire winding mechanism. 3. The rotary encoder, wherein one end of the wire is fixed to a moving part and the other end of the wire is fixed to a fixed side of a traveling shaft.
The linear motor traveling shaft position detection mechanism described. 4. The rotary encoder, wherein one end of the wire is fixed to a fixed side of a traveling shaft, and the other end of the wire is fixed to a moving portion.
The linear motor traveling shaft position detection mechanism described. 5. A rotary encoder having one end of the wire fixed to a fixed side of the traveling shaft and the other end of the wire fixed to a fixed side of the traveling shaft, the middle part of the wire passing through a moving part. The position detecting mechanism for the linear motor traveling shaft according to claim 1 or 2. 6. The one end of the wire is fixed to a moving part, and the other end of the wire is fixed to the other fixed side through a rotary encoder fixed to one fixed side of the traveling shaft. 1. A position detecting mechanism for a linear motor traveling shaft according to 1 or 2. 7. One end of the wire is fixed to one of the moving parts, and the other end of the wire is fixed to the other of the moving parts via a rotary encoder fixed to one fixed side of the traveling shaft. The position detecting mechanism for the linear motor traveling shaft according to claim 1 or 2. 8. A first rotary encoder having one end of the wire fixed to one of the moving portions and the other end of the wire fixed to one fixed side of the traveling shaft, and a first rotary encoder fixed to the other fixed side of the traveling shaft. The position detecting mechanism of the linear motor traveling shaft according to claim 1, wherein the position detecting mechanism is fixed to the other of the moving parts via a rotary encoder of 2. 9. The wire according to claim 1, wherein one end of the wire is fixed to one fixed side of the traveling shaft, and is fixed to the other fixed side of the traveling shaft via a rotary encoder provided in a moving portion. Alternatively, the position detecting mechanism of the linear motor traveling shaft according to the item 2. 10. The position detecting mechanism for a linear motor traveling shaft according to claim 9, wherein the wire is wound around a rotary encoder at least once. 11. The position detecting mechanism for a linear motor traveling shaft according to claim 9, wherein the wire is in pressure contact with a rotary encoder. 12. The position detecting mechanism for a linear motor traveling shaft according to claim 2, wherein the wire winding mechanism includes a wire drum to which torque in one direction is applied by a winding spring.