Abstract:
A linear motor is equipped with sensor substrates that are attached to main motor bodies in the X-direction along a conveyance path in such a manner that the sensor substrates are accommodated within the dimensions of the main motor bodies. Each sensor substrate is equipped with a sensor for outputting an A-phase position detection signal upon detecting a slider, a sensor for outputting a B-phase position detection signal, and a position detection signal summer unit. Each position detection signal summer unit adds up, for A-phase and for B-phase, position detection signals that are output from the position detections unit of the adjoining substrates provided on either side of the relevant substrate.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims benefit of priority to Japanese Patent Application No. 2011-242058 filed on Nov. 4, 2011, and to International Patent Application No. PCT/JP2012/006458 filed on Oct. 9, 2012, the entire content of each of which is incorporated herein by reference. 
     TECHNICAL FIELD 
     The present disclosure relates to a linear motor and a linear conveyance device. 
     BACKGROUND 
     A linear motor comprises a motor body in which a stator is disposed, a mover that faces the stator, and a slider in which the mover is disposed. The slider moves relative to the motor body along a predetermined moving path. One of the stator and the mover may be constituted by a plurality of permanent magnets and the other may be constituted by an electromagnet. Otherwise, both the stator and the mover may be constituted by an electromagnet. When permanent magnets are used, the respective permanent magnets are arranged along the moving path so that different magnetic polarities appear alternately. Moreover, the electromagnet comprises a plurality of cores arranged along the moving path. A coil is attached to each core. Moreover, the linear motor comprises a control device. The control device controls conduction of the coils and causes the slider to move along the moving path while generating attractive force between the stators. 
     In order to detect the position of the slider, a linear scale is provided in the linear motor. For example, in the device disclosed in Japanese Patent Laid-open Publication No. 2003-244929, a linear scale is attached to a slider. The device of Japanese Patent Laid-open Publication No. 2003-244929 further comprises a position detection sensor that detects the linear scale to output a wave signal, an origin sensor that outputs a signal for specifying an origin position of the wave signal, and a sensor substrate for attaching the origin sensor to a motor body. The position detection sensor and the origin sensor output signals according to a moving position of the slider, and the position of the slider is detected based on these signals. 
     However, the sensor substrate of Japanese Patent Laid-open Publication No. 2003-244929 is disposed in a central portion of the stator attached to the motor body in a direction along the moving path. Moreover, the sensors are also laid out in the central portion of the stator. For this reason, there is a problem in that it is not possible to detect the position until the linear scale of the slider reaches the origin sensor disposed in the central portion of the stator. Therefore, as disclosed in Japanese Patent Laid-open Publication No. 2011-101552, the present applicant proposes a linear motor in which an origin sensor is disposed at a position where the origin sensor meets an end of a stator in the direction along a moving path. The linear motor employs a stator unit that comprises a motor body and stators mounted on the motor body. One or more stator units are connected along the moving path to form a linear motor together with a slider that has a mover. The stator unit comprises a sensor head, as a sensor substrate, for each stator. In the sensor head, an origin sensor is disposed at a position where the origin sensor meets an end of the stator in the direction along the moving path. 
     SUMMARY 
     In the configuration of Japanese Patent Laid-open Publication No. 2011-101552, it is possible to obtain origin information immediately at a point in time when the linear scale of the slider starts moving from a certain stator unit among the plurality of stator units to another stator unit adjacent to the stator unit. For this reason, it is possible to detect the position of the slider in a relatively long stroke range. However, in order to dispose the origin sensor at the position where the origin sensor meets the end of the stator in the direction along the moving path, it is necessary to cause the sensor head to be offset relative to the stator unit in the direction along the moving path so that the origin sensor is physically supported. For this reason, a state in which the sensor head protrudes from the end of the stator unit in the direction along the moving path is created. As a result, when the motor body is constituted by one stator unit, it is necessary to protect the protruding portion of the sensor head. Thus, it may be difficult to handle the linear motor. Moreover, when a plurality of stator units are connected to a base, it is necessary to disassemble the stator unit itself. That is, it is necessary to separate the sensor head from the stator unit, install the motor body of the stator unit, and then attach the sensor head to the installed motor body again. For this reason, the operation of connecting the stator units or disassembling the linear motor may become complicated. 
     The present disclosure has been made in view of the above problems, and an object of the present disclosure is to provide a linear motor having easy handling properties while maintaining the function of detecting the position of a slider in a relatively long stroke range. Another object of the present disclosure is to provide a linear conveyance device configured such that a conveying article can be mounted on a slider of the linear motor and to provide a linear conveyance device in which linear motors are connected in a loop so as to circulate the slider configured to mount the conveying article thereon. 
     In order to solve the problems, according to an aspect of the present disclosure, there is provided a linear motor comprising: a slider having a mover; a motor body disposed in a moving path of the slider; and stators attached to the motor body, these stators are arranged along the moving path so that the stators face the mover and move the slider along the moving path while generating attractive force between the stators. 
     Each stator unit comprises: a plurality of sensor substrates attached to the respective stators such that the plurality of sensor substrates is sized within a dimension of the respective stators in a moving direction extending along the moving path; an upstream-side position detecting unit attached to each sensor substrate, the upstream-side position detecting unit being configured to detect the slider in an upstream portion of each sensor substrate in the moving direction and output a position detection signal; a downstream-side position detecting unit attached to each sensor substrate, the downstream-side position detecting unit being configured to detect the slider in a downstream portion of each sensor substrate in the moving direction and output a position detection signal; a position detection signal adding unit attached to each sensor substrate, the position detection signal adding unit being configured to add the position detection signal from the downstream-side position detecting unit of a sensor substrate being adjacent to an upstream side of one sensor substrate in the moving direction and the position detection signal from the upstream-side position detecting unit of a sensor substrate adjacent to a downstream side of the one sensor substrate in the moving direction to obtain an addition signal, and the position detection signal adding unit being capable of outputting the addition signal; and a control device configured to detect a position of the slider relative to one stator to which the one sensor substrate is attached, based on the additional signal from the position detection signal adding unit. 
     According to another aspect of the present disclosure, there is provided a linear conveyance device in which the linear motor is configured to allow a conveying article to be mounted on the slider. 
     The present disclosure provides a significant advantageous effect that a function of detecting the position of the slider in a longer stroke range than the stator can be provided and a device having easy handling properties can be provided. 
     Additional features, objects, configurations, and operational advantages of the present disclosure will become more apparent upon reading the following detailed description along with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view illustrating an entire configuration of a linear conveyance device according to an embodiment of the present disclosure. 
         FIG. 2  is a perspective view illustrating a main part of a stator unit according to the embodiment of  FIG. 1 . 
         FIG. 3  is a schematic side view of the stator unit according to the embodiment of  FIG. 1 . 
         FIG. 4  is a front view when two stator units according to the embodiment of  FIG. 1  are connected. 
         FIG. 5  is a diagram for describing a schematic configuration of a linear scale and sensors of a linear motor according to the embodiment of  FIG. 1 . 
         FIG. 6  is a circuit diagram illustrating a circuit configuration of a plurality of sensor substrates and sensor portions on one end side according to the embodiment of  FIG. 1 . 
         FIG. 7  is a circuit diagram illustrating a circuit configuration of a plurality of sensor substrates and sensor portions on the other end side according to the embodiment of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, best modes for carrying out the present disclosure will be described with reference to the accompanying drawings. 
     First, with reference to  FIG. 1 , a linear conveyance device  10  according to the embodiment of the present disclosure comprises a base  11  that extends in a rectangular form in a plan view, a pair of linear driving units  20 A and  20 B formed on the base  11 , and a slider  30  driven by the linear driving units  20 A and  20 B. In the present embodiment, a first circulating device  40  that circulates the slider  30  from a downstream end of one linear driving unit  20 A (on the forward moving side) to an upstream end of the other linear driving unit  20 B (on the backward moving side) and a second circulating device  50  that circulates the slider  30  from the downstream end of the other linear driving unit  20 B to the upstream end of one linear driving unit  20 A are provided. 
     The base  11  is formed by combining a plurality of tables  11 A. Each table  11 A is formed by forming a rectangular parallelepiped frame as a framework. Each table  11 A comprises a bottom plate, height-adjustable legs attached to four corners of the lower surface of the bottom plate, and a ceiling plate provided above the legs as the framework. In the following description, a longitudinal direction of the base  11  is referred to as an X-direction, and a horizontal direction orthogonal to the X-direction is referred to as a Y-direction. Also, one end side (the left side of  FIG. 3 ) of the Y-direction is referred to as a front side. Moreover, the right side of  FIG. 4  is referred to as one end (the downstream end of the linear driving unit  20 A and the upstream end of the linear driving unit  20 B), and the left side is referred to as the other end (the upstream end of the linear driving unit  20 A and the downstream end of the linear driving unit  20 B). 
     The linear driving units  20 A and  20 B extend in parallel on the base  11  along the X-direction. The front linear driving unit  20 A (on the front side of  FIG. 1 ) forms a forward path (moving path) along which the slider  30  is driven from one end side in the X-direction to the other end side. The rear linear driving unit  20 B (on the rear side of  FIG. 1 ) forms a backward path (moving path) along which the slider  30  is driven from the other end side in the X-direction to one end side. In the present embodiment, these linear driving units  20 A and  20 B form linear motors. Each of the linear motors (the linear driving units  20 A and  20 B) comprises a plurality of stator units  100  and a rail  103 . The stator units  100  have the same specifications and are arranged along the X-direction. The rail  103  is fixed to the upper portion of the plurality of stator units  100  along the X-direction. 
     Hereinafter, the stator units  100  of the linear driving unit  20 A will be described. 
     Referring to  FIGS. 2 to 4 , each stator unit  100  is a device in which a set of four stators  110  having approximately the same specifications is connected. The stator unit  100  comprises a unit frame  101 . The unit frame  101  is formed into a rectangular shape in a plan view and is disposed so that the longitudinal direction thereof extends in the X-direction. The unit frame  101  is fixed to an upper surface of the base  11  by bolts (not illustrated). In the present embodiment, the unit frame  101  is an example of a member that constitutes a motor body of each stator unit  100 . In the illustrated embodiment, covers  102   a  (see  FIG. 3 ) and  102   b  are attached to both front and rear sides of each unit frame  101 . 
     A set of four stators  110  is assembled to the upper portion of the unit frame  101 . The stators  110  are arranged in parallel to the rail  103  on the rear side of the rail  103 . 
     Each stator  110  is constituted by a plurality of magnetic electromagnets  111 . The magnetic electromagnet  111  comprises a core  111   a . The cores  111   a  are arranged in a line in the X-direction. The upper ends of the cores  111   a  are magnetic polarities and the lower ends are connected to an adjacent core  111   a  to form an interdigital shape. A magnetic coil is wound around the core. Reference numeral  111   b  is an assembly of magnetic coils. The magnetic coil assembly  111   b  is arranged in the longitudinal direction of the unit frame  101 . In the illustrated example, a length Ls in the X-direction (the direction along the moving path) of the stator  110  is set to exactly ¼ of a length Lf in the X-direction of the unit frame  101 . On the other hand, as illustrated in  FIG. 2 , four stators  110  are arranged in the longitudinal direction on the upper surface of the unit frame  101 . As a result, when the unit frame  101  is arranged in the X-direction, the stators  110  are connected linearly at an equal pitch along the X-direction. Moreover, the length Ls in the X-direction of the stator  110 , the length L in the X-direction of the unit frame  101 , and a magnetic polarity pitch are set so that a distance (magnetic polarity pitch) between the cores  111   a  adjacent at the end of the stator  110  is the same as a distance between the cores  111   a  adjacent in an intermediate point of the stator  110 . 
     The stator unit  100  comprises a controller  200  (schematically illustrated in  FIG. 3 ) that is provided in each stator  110 . 
     The controller  200  is constituted by a microprocessor and other electronic components and the like. The controllers  200  obtain the positions of the slider  30  relative to the corresponding stators  110  and individually control conduction of the respective magnetic coils of the corresponding stators  110  so as to correspond to the obtained positions. The controllers  200  are configured to control the current supplied to the corresponding stators  110  based on a program or the control of a main control device that controls the entire linear conveyance device. Moreover, each controller  200  is configured to be able to communicate with each other. 
     Referring to  FIG. 4 , four substrates  112 A,  112 B,  112 C, and  112 D are attached to the front side in the Y-direction of the unit frame  101  so as to correspond to the four stators  110  comprised in the unit frame  101 . Plates  113  are attached to the respective substrates  112 A,  112 B,  112 C, and  112 D. A connector  114  is disposed on the plate  113 . A wire harness  115  for realizing wire connection to an external device is connected to the connector  114 . The wire harness  115  is disposed so as to extend toward the front side in the Y-direction of the unit frame  101  (see  FIG. 3 ). 
     The length in the X-direction of the substrates  112 A,  112 B,  112 C, and  112 D is set to be approximately the same as the length Ls of the stator  110 . The substrates  112 A,  112 B,  112 C, and  112 D are arranged in the X-direction at the same arrangement pitch as the stators  110 . Thus, all substrates  112 A,  112 B,  112 C, and  112 D fit within the front surface of the unit frame  101  (that is, the substrates do not protrude from the front surface). Moreover, the arrangement pitch in the X-direction of the substrate  112 A attached to one end side of the unit frame  101  and the substrate  112 D attached to the other end side of another unit frame  101  being adjacent to one end side of the substrate  112 A is set to be the same as the arrangement pitch (or the arrangement pitch of the substrates  112 C and  112 D) of the substrates  112 A and  112 B attached to the unit frame  101 . 
     The connector  114  disposed on the plate  113  is electrically connected to the stator  110  corresponding to the substrate  112 A ( 112 B,  112 C, or  112 D) of the plate  113 , sensors disposed on the substrate  112 A ( 112 B,  112 C, or  112 D) of the plate  113 , and an adder circuit S 8  described later. The wire harness  115  is connected to the connector  114 . Thus, the wire harness  115  electrically connects the corresponding stator  110  and sensors to the controller  200  corresponding to the stator  110 . In this manner, the controller  200  can control conduction of the magnetic coil wound around the magnetic core  111   a  of the corresponding stator  110 . 
     Further, a sub-connector  116  is formed on both sides in the X-direction of each of the substrates  112 A,  112 B,  112 C, and  112 D in order to electrically connect the respective substrates  112 A,  112 B,  112 C, and  112 D. A harness  117  embodied as a flat cable or the like is connected to the sub-connector  116 . The harness  117  electrically connects the adjacent substrates (i.e., combination of the substrate  112 A and the substrate  112 D of the unit frame  101  on the one end of the substrate  112 A; the substrates  112 A and  112 B; the substrates  112 B and  112 C; the substrates  112 C and  112 D; and the substrate  112 D and the substrate  112 A of the unit frame  101  adjacent to the other end side of the substrate  112 D, the same hereinbelow). 
     In the illustrated embodiment, the substrates  112 A,  112 B,  112 C, and  112 D are an example of a sensor substrate of the present disclosure. 
     Referring to  FIGS. 3 and 4 , the slider  30  comprises a sliding member  31  that is fitted on the rail  103 , a top plate  32  attached to an upper portion of the sliding member  31 , and a plurality of permanent magnets  33  as movers that are fixed to a bottom surface of the top plate  32  so as to face the stators  110 . 
     In the illustrated embodiment, a groove that extends in the X-direction is formed in both side portions of the rail  103  as illustrated in  FIG. 3 . The sliding member  31  has a recess portion that has inner walls which are covered by the upper portion of the rail  103  and make sliding contact with the grooves on both side portions. When the recess portion is introduced to the end portion of the rail  103 , the sliding member  31  is connected to the rail  103  so that the sliding member  31  can slide only in the longitudinal direction of the rail  103  in a state where the sliding member  31  can be inserted and removed in the X-direction. 
     The top plate  32  is a structure that moves integrally with the sliding member  31 . The top plate  32  functions as a component for attaching a pallet, for example. A work as a conveying article conveyed by the linear conveyance device  10  is mounted on the pallet. Naturally, the top plate  32  itself may be processed so that a work is mounted directly on the top plate  32 . 
     The plurality of permanent magnets  33  as movers are arranged in a line at a predetermined arrangement pitch along the X-direction so that N and S polarities alternately appear on the lower end surface. On the other hand, the magnetic polarity of the magnetic electromagnet  111  of the stator  110  changes according to the phase of the current supplied to the magnetic coil. The controller  20  supplies a current of any one of different phases u, v, and w to the magnetic coil. When the current is supplied, a magnetic flux occurring in the magnetic electromagnet  111  and a magnetic flux occurring in the permanent magnet  33  react according to a change in the magnetic polarity of the magnetic electromagnet  111 , and attractive force or repulsive force can be generated between the magnetic electromagnet  111  of the stator  110  and the permanent magnet  33  of the slider  30 . Thus, by controlling conduction of the magnetic coil of the magnetic electromagnet  111  when the slider  30  moves, the controller  200  can allow the slider  30  to reciprocate along the X-direction at a predetermined speed. 
     A front end wall  34  is fixed to a bottom surface on the front end side of the top plate of the slider  30 . Two linear scales (magnetic scales)  51  and S 2  included in a position detecting device S are attached to a rear surface (a surface facing the substrates  112 A,  112 B,  112 C, and  112 D) of the front end wall  34 . The position detecting device S is a unit that includes “a position detecting unit” of the present disclosure. 
     Hereinafter, the position detecting device S of the present embodiment will be described. 
     First, referring to  FIGS. 4 and 5 , the magnetic scales S 1  and S 2  are arranged vertically so as to extend in parallel along the X-direction. (in the drawing, the substrates  112 A,  112 B,  112 C, and  112 D are seen from the left side of  FIG. 3 , that is, the front side in the Y-direction and the magnetic scales S 1  and S 2  are depicted by a solid line when seen through from the left side of  FIG. 3 ) 
     The magnetic scale S 1  provided on the upper side comprises a plurality of permanent magnets S 11  and S 12 . The permanent magnets S 11  and S 12  are attached to the rear surface of the front end wall  34  at an equal pitch along the X-direction so that different magnetic polarities appear alternately. In one permanent magnet S 11 , a magnetic polarity of an end surface close to the substrate  112 A ( 112 B,  112 C, or  112 D) in the Y-direction is N-polarity. In the other permanent magnet S 12 , a magnetic polarity of an end surface close to the substrate  112 A ( 112 B,  112 C, or  112 D) in the Y-direction is S-polarity. These permanent magnets S 11  and S 12  are arranged at an equal arrangement pitch within a predetermined scale length L. The scale length L is larger than the length (approximately the same length Ls as the length Ls of the stator  110 ) of the substrate  112 A ( 112 B,  112 C, or  112 D). In the present embodiment, both ends of the magnetic scale S 1  are constituted by the permanent magnet S 11  having the same magnetic polarity. In the illustrated example, although both ends of the magnetic scale S 1  is constituted by the permanent magnet S 11  having the N-polarity (the magnetic polarity of the end surface close to the substrate  112 A ( 112 B,  112 C, or  112 D) in the Y-direction is N-polarity), both ends of the magnetic scale S 1  may be constituted by the permanent magnet S 12  having the S-polarity. 
     Moreover, the magnetic scale S 2  on the lower side is constituted by two sets of permanent magnets S 21  and S 22  attached so as to be aligned vertically. In the permanent magnets S 21  and S 22  that constitute each set, the magnetic polarities of the end surfaces close to the substrate  112 A ( 112 B) are different. One set of permanent magnets S 21  and S 22  is disposed immediately below an end on the other end side of the magnetic scale S 1  on the upper side. Moreover, the other set of permanent magnets S 21  and S 22  is further separated toward the one end side than one set of permanent magnets. The length Lz between one set of permanent magnets S 21  and S 22  and the other set of permanent magnets S 21  and S 22  is set to be larger by a predetermined dimension than the length Ls in the X-direction of the stator  110 . 
     In order to detect the magnetic scale S 1 , a pair of first sensors SA 1  and SA 2  that outputs a sine wave signal (A-phase) and a pair of second sensors SB 1  and SB 2  that outputs a cosine wave signal (B-phase) are provided in the substrates  112 A,  112 B,  112 C, and  112 D. The relation of sine and cosine waves is optional. That is, the A-phase may be a cosine wave and the B-phase may be a sine wave. Further, in order to detect the magnetic scale S 2 , a third sensor SZ that outputs a Z-phase signal (Z-phase) is provided in the substrates  112 A,  112 B,  112 C, and  112 D. The sensors SA 1  to SZ are constituted by a hall sensor, for example, and are configured to measure magnetic flux density of the corresponding permanent magnets S 11 , S 12 , S 21 , and S 22  and output a wave signal of an output voltage (amplitude) corresponding to the magnetic flux density. 
     The first sensors SA 1  and SA 2  are arranged on the corresponding substrate  112 A ( 112 B,  112 C, or  112 D) so that the first sensors SA 1  and SA 2  are separated toward one end side and the other end side on the same line extending along the X-direction. The height of both first sensors SA 1  and SA 2  is set to such a position that the first sensors SA 1  and SA 2  face the magnetic scale S 1  in the Y-direction during assembling. Moreover, during assembling, the first sensors SA 1  and SA 2  face the permanent magnets S 11  and S 12  with a small distance in the Y-direction (front-rear direction) in relation to the magnetic scale S 1 . Similarly, the second sensors SB 1  and SB 2  are arranged on the substrate  112 A ( 112 B,  112 C, or  112 D) so that the second sensors SB 1  and SB 2  are separated toward one end side and the other end side on a line extending in the X-direction. The height of both second sensors SB 1  and SB 2  is set to such a position that the second sensors SB 1  and SB 2  face the magnetic scale S 1  in the Y-direction during assembling. Moreover, during assembling, the second sensors SB 1  and SB 2  face the permanent magnets S 11  and S 12  with a small distance in the Y-direction (front-rear direction) in relation to the magnetic scale S 1 . 
     The distance in the X-direction between one first sensor SA 1  and the other first sensor SA 2  is set in association with the adjacent substrates  112 A,  112 B,  112 C, and  112 D. That is, the distance between the first sensor SA 2  disposed on the other end side of the substrate  112 A on one end side of one substrate  112 B and the first substrate SA 1  disposed on one end side of the substrate  112 C on the other end side of the substrate  112 B is set to be the same as the scale length L. Thus, both first sensors SA 2  and SA 1  face both ends of the magnetic scale S 1  with the substrate  112 B interposed. 
     The same is true for the distance in the X-direction between one second sensor SB 1  and the other second sensor SB 2 . That is, the distance between the second sensor SB 2  disposed on the other end side of the substrate  112 A on one end side of one substrate  112 B and the second sensor SB 1  disposed on one end side of the substrate  112 C on the other end side of the substrate  112 B is set to be the same as the scale length L. Thus, both second sensors SB 2  and SB 1  simultaneously face both ends of the magnetic scale S 1  with the substrate  112 B interposed. 
     Further, the first sensors SA 1  and SA 2  and the second sensors SB 1  and SB 2  are set so that the sensors face permanent magnets S 12  (S 11 ) having different magnetic polarities at the same points in time. 
     The arrangement pitches of the first and second sensors SA 1  and SB 1  and the first and second sensors SA 2  and SB 2  are set to be ½ or 3/2 of the arrangement pitch of the two adjacent permanent magnets S 11  (S 12 ) and S 12  (S 11 ) or one that is a multiplication of an addition of an integer multiple of 2 and the arrangement pitch. 
     Alternatively, when n is an integer of 0 or more, the arrangement pitches are set to one that is a multiplication of an addition of {n±(½)} and the arrangement pitch. As a result, the A-phase wave signal and the B-phase wave signal are in such a relation that one (for example, the A-phase) is a sine wave and the other (for example, the B-phase) is a cosine wave. Thus, the phases of the wave signals output by the first sensors SA 1  and SA 2  and the second sensors SB 1  and SB 2  are shifted by π/2. 
     Both wave signals basically have the same amplitude and are output at the same frequency except that the phases are different. However, the width in the X-direction of the permanent magnets S 11  at both ends of the magnetic scale S 1  is set to be ½ of the width of the remaining permanent magnets S 11  and S 12 . For this reason, magnetic flux density decreases at both ends of the magnetic scale S 1 . Thus, the amplitude of the wave signals output by the first sensors SA 1  and SA 2  at the point in time when the first sensors SA 1  and SA 2  face the permanent magnets S 11  at both ends of the magnetic scale S 1  is ½ of the amplitude of the wave signals output by the first sensors SA 1  and SA 2  at the point in time when the first sensors SA 1  and SA 2  face the permanent magnets S 11  having the same polarities except at both ends of the scale S 1 . The same is true for the amplitude of the wave signals output at the points in time when the second sensors SB 1  and SB 2  face the permanent magnets S 11  having the same polarities at both ends of the magnetic scale S 1 . Thus, even when the first sensors SA 1  and SA 2  simultaneously face both ends of the magnetic scale S 1 , it is possible to prevent the combined wave signal from having a larger amplitude than the wave signal when the other portions are detected. 
     The arrangement pitch which is the distance between an edge of the permanent magnet S 11  at the end and the center in the X-direction of the adjacent permanent magnet S 12  is set to be the same as the arrangement pitch of another two adjacent permanent magnets S 11  and S 12 . 
     Referring to  FIG. 5 , the third sensor SZ is provided in each substrate  112 A ( 112 B,  112 C, or  112 D). Specifically, the third sensor SZ is mounted at a position close to one end side of the stator  110 . For this reason, in the illustrated example, the third sensor SZ is positioned at the same position in the X-direction as the first sensor SA 1  on one end side and the two sensors are provided vertically in the drawing. Moreover, a length Lz between the adjacent third sensors SZ (for example, the length Lz between the third sensor SZ of the substrate  112 B and the third sensor SZ of one substrate  112 C ( 112 D) adjacent to the substrate  112 B) is the same as the length Ls in the X-direction of the stator  110 . Further, suppose a length in the X-direction from the other end of one substrate  112 B to the third sensor SZ of the substrate  112 C adjacent to the other end side is an offset amount L 1 , and a length in the X-direction from one end of the substrate  112 B to the third sensor SZ of the substrate  112 B is an offset amount L 2 , both offset amounts L 1  and L 2  are set as small as possible. As for the length Lz of the third sensors SZ and the offset amounts L 1  and L 2  on both ends, the same is true for the substrates  112 B,  112 C, and  112 D. 
     Since the first sensor SA 1  on one end side is positioned at the same position in the X-direction as the third sensor SZ disposed below the first sensor SA 1 , the length between the first sensors SA 1  of the adjacent substrates (for example,  112 A and  112 B) is equal to Lz. 
     Referring to  FIG. 6 , each of the substrates  112 A,  112 B,  112 C, and  112 D comprises an adder circuit S 8 . 
     Hereinafter, the adder circuit S 8  will be described focusing on the substrate  112 B at the center of  FIG. 6 . 
     The adder circuit S 8  adds the wave signal that the first sensor SA 2  provided on the other end side of the substrate  112 A adjacent to one end side of one substrate  112 B outputs through the harness  117  and the wave signal that the first sensor SA 1  provided on one end side of the substrate  112 C adjacent to the other end side of the substrate  112 B outputs through the harness  117  and outputs the addition signal to the connector  114 . The adder circuit S 8  adds the wave signal that the second sensor SB 2  provided on the other end side of the substrate  112 A adjacent to one end side of one substrate  112 B outputs through the harness  117  and the wave signal that the second substrate SB 1  provided on one end side of the substrate  112 C adjacent to the other end side of the substrate  112 B outputs through the harness  117  and outputs the addition signal to the connector  114 . 
     In addition to the wave signal from the adder circuit S 8 , the connector  114  receives a Z-phase signal from the third sensor SZ provided on the one substrate  112 B and a Z-phase signal from the third sensor SZ of the substrate  112 C adjacent to the other end side of the one substrate  112 B through the harness  117 . Thus, the controller  200  receives an A-phase wave signal and a B-phase wave signal detected on both sides of one substrate  112 B, a Z-phase signal detected by the third sensor SZ of the substrate  112 B, and a Z-phase signal detected by the third sensor SZ of the substrate  112 C on the other end side of the substrate  112 B through the wire harness  115  connected to the connector  114 . 
     For example, in the linear driving unit  20 A on the forward path side, the slider  30  moves from one end side to the other end side. In this case, the A-phase wave signal from the first sensor SA 2  on the other end side of the substrate  112 A adjacent to one end side and the B-phase wave signal from the second sensor SB 2  are input to the adder circuit S 8  of the substrate  112 B, for example. The adder circuit S 8  adds these wave signals by each of the A-phases and each of the B-phases and outputs respective addition signals. These addition signals are input to the controller  200  of the substrate  112 B through the wire harness  115 . On the other hand, the output from the first and second sensors SA 1  and SB 1  to the controller  200  of the substrate  112 B is 0 until the slider  30  reaches the first sensor SA 1  on one end side of the substrate  112 C adjacent to the other end side. 
     When the slider  30  moves further to the other end side, the third sensor SZ of the substrate  112 B detects one set of permanent magnets S 21  and S 22  on the other end side of the magnetic scale S 2  and outputs a Z-phase signal. These output signals are input to the controller  200  of the substrate  112 B. Moreover, the controller  200  of the substrate  112 B counts a change in the amplitude of the A- and B-phase wave signals from the substrate  112 A adjacent to one end side after the point in time when the magnetic scale S 2  on the other end side passes through the third sensor SZ. Based on this signal, the controller  200  of the substrate  112 B can obtain the position of the slider  30  relative to the origin position. 
     When the slider  30  moves further toward the other end side, the permanent magnet S 11  on one end side of the magnetic scale S 1  reaches the first sensor SA 2  on the other end side of the substrate  112 A. At the same time, the permanent magnet S 11  on the other end side of the magnetic scale S 1  reaches the first sensor SA 1  on one end side of the substrate  112 C. At this point in time, the A-phase wave signal having ½ amplitude output from the first sensor SA 2  on the other end side of the substrate  112 A and the A-phase wave signal of ½ amplitude output from the first sensor SA 1  on one end side of the substrate  112 C are input to the adder circuit S 8  of the substrate  112 B. On the other hand, the adder circuit S 8  adds the A-phase wave signal of ½ amplitude output from the first sensor SA 2  on the other end side of the substrate  112 A and the A-phase wave signal of ½ amplitude output from the first sensor SA 1  on one end side of the substrate  112 C. Moreover, the adder circuit S 8  outputs an A-phase wave signal of 2/2 amplitude. Thus, the A-phase wave signal of 2/2 amplitude output from the adder circuit S 8  is input to the controller  200  of the substrate  112 B. Thus, the continuity is maintained between the wave signal when both substrates  112 A and  112 B adjacent to the substrate  112 B detect an end of the magnetic scale S 1  and the wave signal when only one of both substrates  112 A and  112 B adjacent to the substrate  112 B detects the magnetic scale S 1 . As a result, the A-phase wave signal input to the controller  200  of the substrate  112 B is processed as a series of smooth A-phase wave signals. 
     At a point in time when the permanent magnet S 11  on the other end side of the magnetic scale S 1  reaches the first sensor SA 1  on one end side of the substrate  112 C, the permanent magnets S 21  and S 22  on the other end side of the magnetic scale S 2  also reach the third sensor SZ of the substrate  112 C. In the subsequent point in time, similarly to the controller  200  of the substrate  112 B, the controller  200  of the substrate  112 C can detect the position of the slider  30  relative to the corresponding stator  110  based on detection of the third sensor SZ. 
     As a result, the controller  200  of the substrate  112 C can detect the position of the slider  30  relative to the stator  110  based on the input A-, B-, and Z-phase signals. Therefore, the controller  200  controls the conduction of the magnetic coil of the magnetic electromagnet  111  so as to correspond to the position of the slider  30  based on a predetermined program with the aid of a main control device, and control the movement of the slider  30 . 
     When the slider  30  moves further toward the other end side, the permanent magnet S 11  on one end side of the magnetic scale S 1  moves away from the first sensor SA 2  on the other end side of the substrate  112 A and reaches the second sensor SB 2  on the other end side. At the same time, the permanent magnet S 11  on the other end side of the magnetic scale S 1  reaches the second sensor SB 1  on one end side of the substrate  112 C. At this point in time, a B-phase wave signal of ½ amplitude output from the second sensor SB 2  of the substrate  112 A and a B-phase wave signal of ½ amplitude output from the first sensor SB 1  of the substrate  112 C are input to the adder circuit S 8  of the substrate  112 B. On the other hand, the adder circuit S 8  adds the B-phase wave signal of ½ amplitude from the second sensor SB 2  on the other end side of the substrate  112 A and the B-phase wave signal of ½ amplitude from the second sensor SB 1  on one end side of the substrate  112 C. Moreover, the adder circuit S 8  outputs a B-phase wave signal of 2/2 amplitude. Thus, the B-phase wave signal of 2/2 amplitude output from the adder circuit S 8  is input to the controller  200  of the substrate  112 B. Therefore, continuity of the B-phase wave signal is maintained. As a result, the B-phase wave signal input to the controller  200  of the substrate  112 B is processed as a series of smooth B-phase wave signals. 
     When the slider  30  moves further toward the other end side, the permanent magnet S 11  on one end side of the magnetic scale S 1  moves away from the second sensor SB 2  on the other end side of the substrate  112 A adjacent to one end side. Thus, the output from the first and second sensors SA 2  and SB 2  on the other end side of the substrate  112 A is 0. On the other hand, the permanent magnets S 11  and S 12  on the other end side of the magnetic scale S 1  continuously face the first and second sensors SA 1  and SB 1  on one end side of the substrate  112 C adjacent to the other end side. Thus, the A-phase wave signal of 2/2 amplitude and the B-phase wave signal of 2/2 amplitude are output from the first and second sensors SA 1  and SB 1 , respectively. These A- and B-phase wave signals are added to the output from the first and second sensors SA 2  and SB 2  on the other end side of the substrate  112 A by the adder circuit S 8  of the substrate  112 B and are input to the controller  200  of the substrate  112 B. The input wave signals of the respective A- and B-phases are added to the A- and B-phase wave signals that have already been input to the controller  200 . Here, the added A- and B-phase wave signals are wave signals of 2/2 amplitude. Thus, continuity between these A- and B-phase wave signals and the respective signals that have already been input is secured. The controller  200  of the substrate  112 B can detect the position of the slider  30  relative to the stator  110  to which the substrate  112 B is attached by counting the respective wave signals after the adding. 
     In this manner, the controller  200  of one substrate (for example,  112 B) can detect the position of the slider  30  in a longer stroke range in the X-direction than the stator  110  using the output of the sensors on the substrates disposed on both sides of the substrate  112 B. Moreover, when a certain substrate is positioned at an end of the unit frame  101 , the output of the sensors on the substrate of the unit frame  101  adjacent to the unit frame  101  can be output. 
     In the present embodiment, the first and second sensors SA 1  and SA 2  on one end side are an example of an upstream-side position detecting unit of the present disclosure. On the other hand, the first and second sensors SA 2  and SB 2  on the other end side are an example of a downstream-side position detecting unit of the present disclosure. Moreover, in the present embodiment, the adder circuit S 8  is an example of a position detection signal adding unit. The position detecting device S according to the present embodiment includes the first and second sensors SA 1  and SB 1  on one end side, the first and second sensors SA 2  and SB 2  on the other end side, the third sensor SZ, and the magnetic scales S 1  and S 2 . 
     Subsequently, in the linear driving unit  20 B on the backward path side, four substrates  112 A,  112 B,  112 C, and  112 D are sequentially attached to the front side in the Y-direction of the unit frame  101  in that order from one end side to the other end side so as to correspond to the four stators  110  that constitute the unit frame  101  similarly to the linear driving unit  20 A on the forward path side. The plate  113  is attached to the respective substrates  112 A,  112 B,  112 C, and  112 D. The connectors  114  are disposed on the plates  113 . The wire harnesses  115  for realizing wire connection to an external device are connected to the connectors  114 . The wire harness  115  is disposed so as to extend toward the front side in the Y-direction of the unit frame  101 . 
     In the linear driving unit  20 B on the backward path side, the slider  30  moves from the other end side to one end side. Hereinafter, a detecting process on the backward path side will be described focusing on the substrate  112 B. 
     For example, at a point in time when the permanent magnet S 11  on one end side of the magnetic scale S 1  passes through the first sensor SA 1  on one end side of the substrate  112 C on the upstream side of one substrate  112 B, the first and second sensors SA 1  and SB 1  on one end side of the substrate  112 C output A- and B-phase wave signals. Moreover, the third sensor SZ outputs a Z-phase signal. The A- and B-phase wave signals are input to the adder circuit S 8  of the substrate  112 B through the harness  117 . Moreover, the Z-phase signal is input to the controller  200  of the substrate  112 C and is also input to the controller  200  of the substrate  112 B through the harness  117  and the wire harness  115 . The adder circuit S 8  outputs the A- and B-phase wave signals through the wire harness  115 . The output A- and B-phase wave signals are input to the controller  200  of the substrate  112 B together with the Z-phase signal output from the third sensor SZ of the substrate  112 C. After that, the A-, B-, and Z-phase signals are input to the controller  200  of the substrate  112 B until the slider  30  reaches the substrate  112 A and the magnetic scale S 1  passes through the first sensor SA 1  (thus, the third sensor SZ of the substrate  112 B) on one end side of the substrate  112 B similarly to the linear driving unit  20 A on the forward moving side. 
     The controller  200  of the substrate  112 B counts a change in the amplitude of the A-phase wave signal from the first sensor SA 1  on one end side of the substrate  112 C and the B-phase wave signal from the second sensor SB 1  after one set of permanent magnets S 21  and S 22  on one end side of the magnetic scale S 2  reaches the third sensor SZ of the substrate  112 C. Based on this signal processing, the controller  200  of the substrate  112 B can detect the position of the slider  30 . At this point in time, any one of the permanent magnets S 11  and S 12  of the magnetic scale S 1  does not reach the first and second sensors SA 2  and SB 2  on the other end side of the substrate  112 A on one end side. Thus, the wave signals having 2/2 amplitude of the sensors SA 1  and SB 1  on one end side of the substrate  112 C are input to the substrate  112 B. 
     At a point in time when the slider  30  moves further from the other end side to one end side and the permanent magnet S 11  on one end side of the magnetic scale S 1  reaches the second sensor SB 2  on the other end side of the substrate  112 A, the permanent magnet S 11  on the other end side of the magnetic scale S 1  reaches the second sensor SB 1  on one end side of the substrate  112 C. Thus, the B-phase wave signal having ½ amplitude from the second sensor SB 2  on the other end side of the substrate  112 A and the B-phase wave signal having ½ amplitude from the second sensor SB 1  on one end side of the substrate  112 C are input to the adder circuit S 8  of the substrate  112 B through the corresponding harness  117 . The adder circuit S 8  adds these B-phase wave signals and outputs an addition signal having 2/2 amplitude. The output addition signal is input to the controller  200  of the substrate  112 B. The addition signal having 2/2 amplitude input to the controller  200  is added to the B-phase wave signal that has been output from the second sensor SB 1  on one end side of the substrate  112 C adjacent to the other end side. The added addition signal is smoothly continuous to the previous wave signal. 
     Similarly, at a point in time when the permanent magnet S 11  on one end side of the magnetic scale S 1  reaches the first sensor SA 2  on the other end side of the substrate  112 A, the permanent magnet S 11  on the other end side of the magnetic scale S 1  reaches the first sensor SA 1  on one end side of the substrate  112 C. Thus, the A-phase wave signal having ½ amplitude from the first sensor SA 2  on the other end side of the substrate  112 A and the A-phase wave signal having ½ amplitude from the first sensor SA 1  on one end side of the substrate  112 C are input to the adder circuit S 8  of the substrate  112 B through the corresponding harness  117 . The adder circuit S 8  adds these A-phase wave signals and outputs an addition signal having 2/2 amplitude. The output addition signal is input to the controller  200  of the substrate  112 B. The addition signal having 2/2 amplitude input to the controller  200  is added to the A-phase wave signal that has been output from the first sensor SA 1  on one end side of the substrate  112 C adjacent to the other end side. The added addition signal is smoothly continuous to the previous wave signal. Further, at a point in time when the permanent magnet S 11  on one end side of the magnetic scale S 1  reaches the first sensor SA 2  on the other end side of the substrate  112 A, one set of permanent magnets S 21  and S 22  on one end side of the magnetic scale S 2  is detected by the third sensor SZ of the substrate  112 B. Moreover, at this point in time, one set of permanent magnets S 21  and S 22  on the other end side of the magnetic scale S 2  is detected by the third sensor SZ of the substrate  112 C. Thus, even in the course of processes in which one set of permanent magnets S 21  and S 22  on one end side of the magnetic scale S 2  passes through the substrate  112 C and is detected by the third sensor SZ of the substrate  112 B, an origin signal is output so as to correspond to the length Lz. As a result, the controller  200  of the substrate  112 B can accurately compute the position of the slider  30  without losing origin information. 
     As a result, the controller  200  of the substrate  112 B detects the position of the slider  30  relative to the stator  110  based on the input A-, B-, and Z-phase signals, controls conduction of the magnetic coil of the magnetic electromagnet  111  based on a predetermined program with the aid of a main control device, and controls the movement of the slider  30 . 
     Next, referring to  FIG. 1 , the first circulating device  40  of the linear conveyance device  10  comprises a conveying unit  41 , a driving unit  42 , a slider conveying unit  43 , and a slider conveying unit  44 . 
     The conveying unit  41  is a unit that can reciprocate in the Y-direction on the other end side of the linear driving unit  20 A on the forward path side and the linear driving unit  20 B on the backward path side. A reception position of the slider  30  is set at the downstream end on the other end side of the linear driving unit  20 A on the forward path side. Moreover, a transfer position at which the slider  30  is transferred to the other end side of the linear driving unit  20 B on the backward path side is set at the upstream end on the other end side of the linear driving unit  20 B on the backward path side. At the reception position, the slider  30  is received in the conveying unit  41  from the other end side of the linear driving unit  20 A of the forward path side. At the transfer position, the slider  30  is transferred from the conveying unit  41  to the other end side of the linear driving unit  20 B on the backward path side without changing its attitude. 
     The driving unit  42  is a unit that drives the conveying unit  41  between the reception position and the transfer position. 
     The slider conveying unit  43  can engage with and disengage from the slider  30 . The slider conveying unit  43  engages with the slider  30  positioned in the linear driving unit  20 A on the forward path side and conveys the engaged slider  30  to the reception position. When the conveying unit  41  waits at the reception position, the slider conveying unit  43  conveys the slider  30  to the reception position from the downstream end of the linear driving unit  20 A. In this way, the slider  30  is received on the conveying unit  41  without changing its posture. After that, the driving unit  42  conveys the conveying unit  41  from the reception position to the transfer position. 
     The slider conveying unit  44  can engage with and disengage from the slider  30 . The slider conveying unit  44  engages with the slider  30  positioned on the conveying unit  41  having arrived at the transfer position and conveys the engaged slider  30  to the upstream end of the linear driving unit  20 B. When the conveying unit  41  arrives at the transfer position, the slider conveying unit  44  conveys the slider  30  from the conveying unit  41  to the other end side of the linear driving unit  20 B on the backward path side. In this way, the slider  30  is transferred to the other end side of the linear driving unit  20 B on the backward path side without changing its posture. 
     In this manner, in the present embodiment, the slider  30  conveyed from the linear driving unit  20 A on the forward path side can be circulated to the linear driving unit  20 B on the backward path side while maintaining the same posture. 
     Next, the second circulating device  50  comprises a conveying unit  51 , a driving unit  52 , a slider conveying unit  53 , and a slider conveying unit  54 . 
     The conveying unit  51  is a unit that can reciprocate in the Y-direction on one end side of the linear driving unit  20 B on the backward path side and the linear driving unit  20 A on the forward path side. A reception position of the slider  30  is set at the downstream end on one end side of the linear driving unit  20 B on the backward path side. Moreover, a transfer position at which the slider  30  is transferred to one end side of the linear driving unit  20 A on the forward path side is set at the upstream end on one end side of the linear driving unit  20 A on the forward path side. At the reception position, the slider  30  is received in the conveying unit  51  from one end side of the linear driving unit  20 B on the backward path side. At the transfer position, the slider  30  is transferred from the conveying unit  51  to one end side of the linear driving unit  20 A on the forward path side without changing its posture. 
     The driving unit  52  is a unit that drives the conveying unit  51  between the reception position and the transfer position. 
     The slider conveying unit  53  can engage with and disengage from the slider  30 . The slider conveying unit  53  engages with the slider  30  positioned in the linear driving unit  20 B on the backward path side and conveys the engaged slider  30  to the reception position. When the conveying unit  51  waits at the reception position, the slider conveying unit  53  conveys the slider  30  to the reception position from the downstream end of the linear driving unit  20 B. In this way, the slider  30  is received on the conveying unit  51  without changing its posture. After that, the driving unit  52  conveys the conveying unit  51  from the reception position to the transfer position. 
     The slider conveying unit  54  can engage with and disengage from the slider  30 . The slider conveying unit  54  engages with the slider  30  positioned in the conveying unit  51  having arrived at the transfer position and conveys the engaged slider  30  to the upstream end of the linear driving unit  20 A. When the conveying unit  51  arrives at the transfer position, the slider conveying unit  54  conveys the slider  30  from the conveying unit  51  to one end side of the linear driving unit  20 A on the forward path side. In this way, the slider  30  is transferred to one end side of the linear driving unit  20 A on the forward path side without changing its posture. 
     In this manner, in the present embodiment, the slider  30  conveyed from the linear driving unit  20 B on the backward path side can be circulated to the linear driving unit  20 A on the forward path side while maintaining the same posture. At the transfer position of the second circulating device  50 , an operator can arbitrarily introduce the slider  30  to the linear driving unit  20 A on the forward path side. The number of sliders  30  introduced simultaneously to the linear driving units  20 A and  20 B can be optionally set within a range where overflow does not occur. 
     The linear conveyance device  10  comprises a plurality of linear motors (the linear driving unit  20 A on the forward path side and the linear driving unit  20 B on the backward path side) and a circulating device that circulates the slider from the other end of the linear motors to one end of the adjacent linear motor. The plurality of linear motors and the plurality of circulating devices form a circulation path of the slider so that one or more sliders moves to the circulation path. 
     Here, in the illustrated embodiment, a one-end-side sensor substrate  60 A as an auxiliary sensor substrate is provided in the second circulating device  50  of each of the linear driving units  20 A and  20 B. Moreover, an other-end-side sensor substrate  61 A as an auxiliary sensor substrate is provided in the first circulating device  40  of each of the linear driving units  20 A and  20 B. 
     In the second circulating device  50 , the one-end-side sensor substrate  60 A is disposed to be adjacent to the upstream side of the substrate  112 A of the stator  110  that forms the upstream end of the linear driving unit  20 A on the forward path side and the downstream side of the substrate  112 A of the stator  110  that forms the downstream end of the linear driving unit  20 B on the backward path side. 
     Similarly, in the first circulating device  40 , the other-end-side sensor substrate  61 A is disposed to be adjacent to the downstream side of the substrate  112 D of the stator  110  that forms the downstream end of the linear driving unit  20 A on the forward path side and the upstream side of the substrate  112 D of the stator  110  that forms the upstream end of the linear driving unit  20 B on the backward path side. 
     Referring to  FIG. 6 , the first sensor SA 2  and the second sensor SB 2  are provided on the one-end-side sensor substrates  60 A of the linear driving unit  20 A on the forward path side and the linear driving unit  20 B on the backward path side. Moreover, the sub-connector  116  is provided on the other end side of the one-end-side sensor substrate  60 A. The harness  117  is connected to the sub-connector  116 . The one-end-side sensor substrates  60 A and the substrates  112 A adjacent to one-end-side sensor substrates  60 A on one end side are connected by the harnesses  117 . 
     Moreover, the controller  200  connected to the substrate  112 A adjacent to the downstream side of the one-end-side sensor substrates  60 A receives an addition signal between the A-phase wave signal from the first sensor SA 1  provided in the substrate  112 B and the A-phase wave signal from the first sensor SA 2  provided in the one-end-side sensor substrate  60 A. Moreover, the controller  200  connected to the substrate  112 A receives an addition signal between the B-phase wave signal from the second sensor SB 1  provided in the substrate  112 B and the B-phase wave signal from the second sensor SB 2  provided in the one-end-side sensor substrate  60 A. Further, the controller  200  connected to the substrate  112 A receives the Z-phase signal from the third sensor SZ of the substrate  112 A. The controller  200  connected to the substrate  112 A detects the position of the slider  30  relative to the stator  110  to which the substrate  112 A is attached based on these signals. 
     Referring to  FIG. 7 , the first sensor SA 1 , the second sensor SB 1 , and the third sensor SZ are provided on the other-end-side sensor substrates  61 A of the linear driving unit  20 A on the forward path side and the linear driving unit  20 B on the backward path side. The sub-connector  116  is provided on one end side of the other-end-side sensor substrate  61 A. The harness  117  is connected to the sub-connector  116 . The other-end-side sensor substrates  61 A and the substrates  112 D adjacent to the other-end-side sensor substrates  61 A are connected by the harnesses  117 . 
     Moreover, the controller  200  connected to the substrate  112 D adjacent to the upstream side of other-end-side sensor substrates  61 A receives an addition signal between the A-phase wave signal from the first sensor SA 2  provided in the substrate  112 C and the A-phase wave signal from the first sensor SA 1  provided in the other-end-side sensor substrate  61 A. Further, the controller  200  connected to the substrate  112 D receives an addition signal between the B-phase wave signal from the second sensor SB 2  provided in the substrate  112 C and the B-phase wave signal from the second sensor SB 1  provided in the other-end-side sensor substrate  61 A. As for a Z-phase signal, in the linear driving unit  20 A on the forward path side, the controller  200  connected to the substrate  112 D adjacent to the upstream side of the other-end-side sensor substrate  61 A detects the Z-phase signal from the third sensor SZ of the substrate  112 D. In the linear driving unit  20 B on the backward path side, the controller  200  connected to the substrate  112 D adjacent to the downstream side of the other-end-side sensor substrate  61 A detects the Z-phase signal from the third sensor SZ provided in the other-end-side sensor substrate  61 A and detects the Z-phase signal from the third sensor SZ of the substrate  112 D adjacent to the downstream side of the other-end-side sensor substrate  61 A. Based on these Z-phase signals, the controllers  200  detect the position of the slider  30  relative to the stator  110  to which the corresponding substrate  112 D is attached. 
     As described above, according to the linear conveyance device  10  of the present embodiment, the linear driving unit  20 A on the forward path side and the linear driving unit  20 B on the backward path side that drive the slider  30  in the X-direction (the direction along the moving path) each comprise a plurality of stator units  100 . Each stator unit  100  comprises stators  110 . Each stator  110  comprises the sensor substrates  112 A to  112 B. The sensor substrates  112 A to  112 B each comprise the adder circuit S 8 . The adder circuit S 8  adds the position detection signals from the position detecting unit provided in the substrates  112 A and  112 C on both sides of one substrate  112 B and outputs an addition signal. The controller  200  connected to one substrate  112 B obtains the position of the slider  30  relative to the stator  110  based on the addition signal output by the adder circuit S 8 . Thus, the controller  200  can detect the position of the slider  30  relative to the stator  110  in a movement stroke range of the slider  30  that is longer than the length (that is, the length Ls of the stator  110 ) of the substrate  112 B provided in the stator  110 . 
     Further, since the substrates  112 A to  112 D as the plurality of sensor substrates fit within the inner side of the unit frame  101  that forms the motor body of the corresponding stator unit  100 , a superfluous protruding portion will not occur. For this reason, when the stator unit  100  is a single body, it is remarkably easy to handle the stator unit  100 . Moreover, when a plurality of stator units  100  are newly connected to the base  11  or the like, the connected stator unit  100  is removed, or the stator unit  100  is added to the existing linear driving units  20 A and  20 B, and it is not necessary to disassemble the stator unit  100  itself (that is, it is not necessary to perform an operation of attaching or detaching the substrate  112 A or  112 D to the unit frame  101 ). Thus, it is possible to obtain a linear conveyance device that has good efficiency in connecting and removing operations. 
     Moreover, in the present embodiment, the first sensors SA 1  and SA 2  and the second sensors SB 1  and SB 2  are provided in each of the sensor substrates  112 A,  112 B,  112 C, and  112 D as the position detecting unit. The first sensors SA 1  and SA 2  constitutes a set of two hall sensors, one of which is a hall sensor (the sensor SA 1 ) disposed on one end side of the stator  110  in the X-direction and the other is a hall sensor (the sensor SA 2 ) disposed on the other end side of the stator  110 . Moreover, similarly, the second sensors SB 1  and SB 2  form a set of two sensors of which one is a hall sensor (the sensor SB 1 ) disposed one end side of the stator  110  in the X-direction and the other is a hall sensor (the sensor SB 2 ) disposed on the other end side of the stator  110 . Moreover, the adder circuit S 8  forms a position detection signal adding unit that adds the position detection signal from the hall sensor disposed on the other end side of the stator  110  adjacent to one end of each stator  110  in each sensor set and the position detection signal from the hall sensor disposed on one end side of the stator  110  adjacent to the other end side and outputs a continuous wave signal to each sensor set. 
     Thus, in the present embodiment, the stators  110  corresponding to the respective substrates  112 A to  112 D have the same dimensions. Thus, it is possible to detect the position of the mover in a relatively wide stroke range even if the respective substrates  112 A to  112 D are fixed to the unit frame  101  flush without being offset in the X-direction. Moreover, in the present embodiment, the arrangement pitch between the first sensor SA 1  and the second sensor SB 1  and the arrangement pitch between the first sensor SA 2  and the second sensor SA 2  are, for example, ½ or 3/2 of the arrangement pitch between the adjacent permanent magnets S 11  and S 12  of the magnetic scale S 1 . That is, the arrangement pitch in the X-direction of one end and the other ends of the sensors that form the two sensor sets is a multiplication of {n+(½)} (where n is an integer of 0 or more) and the arrangement pitch of the plurality of permanent magnets S 11  and S 12  that constitutes the magnetic scale S 1 . For this reason, the wave signal output by the sensor set formed by the respective first sensors SA 1  and SA 2  and the wave signal output by the sensor set formed by the respective second sensors SB 1  and SB 2  have phases that are offset by π/2 in relation to each other. Thus, in the present embodiment, by using two sets of sensors so that one outputs a sine wave and the other outputs a cosine wave, it is possible to improve resolution and to provide a high-precision position detecting function. 
     Moreover, in the present embodiment, the third sensor SZ as the origin sensor is provided at a position near one end side of the stator  110  in the X-direction. For this reason, the length Ls of the stator  110  and the offset amounts L 1  and L 2  in the X-direction decrease as much as possible. Thus, the origin information can be obtained immediately at the point in time when the magnetic scale S 1  of the slider  30  starts moving from a certain stator  110  in the stator unit  100  to a stator  110  adjacent to the stator  110  and at the point in time when the magnetic scale S 1  starts moving from a certain stator unit  100  in the plurality of stator units  100  to another stator unit  100  adjacent to the stator unit  100 . As a result, it is possible to detect the position of the slider  30  in a relatively long stroke range. 
     Moreover, in the present embodiment, the linear driving unit  20 A on the forward path side comprises the one-end-side sensor substrate  60 A attached to be adjacent to an end on one end side (the upstream side in the moving direction of the slider  30 ) and the other-end-side sensor substrate  61 A attached to be adjacent to the end on the other end side. Further, the linear driving unit  20 B on the backward path side comprises the one-end-side sensor substrate  60 A attached to be adjacent to the end on the one end side (the downstream side in the moving direction of the slider  30 ) and the other-end-side sensor substrate  61 B attached to be adjacent to the end on the other end side. In each one-end-side sensor substrate  60 A, the first sensor SA 2  and the second sensor SB 2  corresponding to the other-end-side sensors of the substrates  112 A,  112 B,  112 C, and  112 D are provided. In each other-end-side sensor substrate  61 A, the first sensor SA 1 , the second sensor SB 1 , and the third sensor SZ corresponding to the one-end-side sensors of the substrates  112 A,  112 B,  112 C, and  112 D are provided. 
     Thus, in the present embodiment, in the upstream end of the linear driving unit  20 A on the forward path side, the controller  200  of the stator  110  that forms the upstream end can receive signals output from the one-end-side sensor substrate  60 A as the auxiliary sensor substrate. Thus, the controller  200  can detect the positions of the sliders  30  that enter the stator  110  that forms the upstream end of the linear driving unit  20 A based on the signal output from the third sensor SZ of the substrate  112 A disposed on the stator  110 , the signal output from the substrate  112 B adjacent to the downstream side of the substrate  112 A, and the signal output from the one-end-side sensor substrate  60 A and control the movement of the sliders  30 . Thus, when the slider  30  circulating from the second circulating device  50  enters the stator  110  on the most upstream side or when the operator disposes the slider  30  in the stator  110  on the most upstream side, the controller  200  can immediately detect the position of the slider  30  and control the movement of the slider  30 . 
     Moreover, in the downstream end of the linear driving unit  20 A on the forward path side, the controller  200  of the stator  110  that forms the downstream end can also receive signals output from the sensor substrate  61 A as the auxiliary sensor substrate. Thus, the controller  200  can detect the position of the slider  30  that leaves from the end of the stator  110  that forms the downstream end of the linear driving unit  20 A based on the signal output from the third sensor SZ of the substrate  112 D of the stator  110 , the signal output from the substrate  112 C on the upstream side of the substrate  112 D, and the signal output from the sensor substrate  61 A and control the movement of the slider  30 . 
     Similarly, in the upstream end of the linear driving unit  20 B on the backward path side, the controller  200  of the stator  110  that forms the upstream end can also receive signals output from the other-end-side sensor substrate  61 A as the auxiliary sensor substrate. Thus, the controller  200  can detect the position of the slider  30  transferred to the stator  110  that forms the upstream end of the linear driving unit  20 B based on the signal output from the third sensor SZ of the substrate  112 D provided in the stator  110 , the signal output from the substrate  112 C adjacent to the downstream side of the substrate  112 D, and the signal output from the other-end-side sensor substrate  61 A and control the transfer operation. Thus, when the slider  30  is transferred to the upstream end from the first circulating device  40  so that the slider  30  enters the stator  110  on the most upstream side, it is possible to immediately detect the position of the slider  30  and to control the movement of the slider  30 . 
     Moreover, in the downstream end of the linear driving unit  20 B on the backward path side, the controller  200  of the stator  110  that forms the downstream end can receive the signals from the sensor substrate  60 A as the auxiliary sensor substrate. Thus, the controller  200  can detect the position of the slider  30  transferred to the second circulating device  50  from the stator  110  that forms the downstream end of the linear driving unit  20 B based on the signal output from the third sensor SZ of the substrate  112 A of the stator  110 , the signal output from the substrate  112 B adjacent to the upstream side of the substrate  112 A, and the signal output from the one-end-side sensor substrate  60 A and control the movement of the slider  30 . 
     Moreover, in the present embodiment, the substrates ( 112 A and  112 B,  112 B and  112 C,  112 C and  112 D,  112 D and  112 A, or  60 A and  112 A, and  112 D and  61 A) arranged on both sides are electrically connected by the harness  117 . In this configuration, since the substrates  112 A to  112 D of which the dimension in the X-direction is approximately the same as the dimension Ls in the X-direction of the stator  111  are employed, it is possible to shorten the harness  117  as much as possible. Thus, in the harness  117 , there is no problem of noise superposition and it is possible to switch a differential transfer scheme to a single-end transfer scheme. 
     The present disclosure is not limited to the above embodiment, and naturally, various changes can be made without departing from the spirit of the present disclosure. 
     For example, the sensor is ideally a hall sensor, and a sensor device other than the hall sensor may also be used. The expressions such as linear or rectilinear are used for engineering reasons and are not intended to exclude a curved path. 
     Moreover, the linear driving unit  20 A on the forward path side may be rotated by 180° as viewed from the above so as to replace the linear driving unit  20 B on the forward path side of the above-described embodiment so that the linear driving unit on the forward path side has the same configuration as the linear driving unit  20 A on the backward path side. In this case, the substrates  112 A to  112 D, the connectors  114  and  116 , and the wire harnesses  115  and  117  are on the front side in the Y-direction on the forward path side and are on the rear side in the Y-direction on the backward path side. Thus, inspection and maintenance properties are improved. 
     In the linear motor according to the present disclosure, the position detection signal adding unit of the sensor substrate adds the position detection signal from the downstream-side position detecting unit of a sensor substrate being adjacent to an upstream side of one sensor substrate in the moving direction and the position detection signal from the upstream-side position detecting unit of a sensor substrate being adjacent to a downstream side of the one sensor substrate in the moving direction to obtain an addition signal and outputs the addition signal. For this reason, even if the sensor substrates fit within the corresponding stator, the control device can detect the position of the slider relative to the stator in a movement stroke range of the slider that is longer than the length of one stator similarly to the configuration of Japanese Patent Laid-open Publication No. 2011-101552. On the other hand, since the respective sensor substrates are attached so as to fit within the dimension of the corresponding stator, a superfluous protruding portion will not occur. Therefore, when the linear motor is constituted by a single stator unit, it is remarkably easy to handle the linear motor. Moreover, where stators or stator units are connected to a base or the like to form the linear motor, or where a linear motor constituted by connecting stators or stator units are disassembled, it is not necessary to perform an operation such as attaching or detaching the sensor substrate. Therefore, the efficiency of an operation of connecting the stators or the stator units or disassembling the linear motor is improved. 
     In the linear motor according to a preferred aspect, the linear motor further comprises a magnetic scale facing both the upstream-side position detecting unit and the downstream-side position detecting unit, and the magnetic scale comprises a plurality of magnets arranged at an equal pitch to the slider so that S and N magnetic polarities alternately appear along the moving direction. In this aspect, since the position of the slider relative to the one stator is detected using a scale having the length of an actual stator, it is possible to detect the position more accurately. 
     In the linear motor according to a preferred aspect, a length of the magnetic scale, an arrangement of the magnets, and a distance in the moving direction between the downstream-side position detecting unit and the upstream-side position detecting unit are set such that, when the downstream-side position detecting unit of the sensor substrate adjacent in the moving direction to the upstream side of the one sensor substrate faces an upstream end of the magnetic scale, the upstream-side position detecting unit of the sensor substrate adjacent in the moving direction to the downstream side of the one sensor substrate faces a downstream end of the magnetic scale, and a magnetic polarity of the upstream end of the magnetic scale and a magnetic polarity of the downstream end of the magnetic scale are the same as any one of the S and N polarities. 
     In this aspect, the position detection signal based on detection of the magnetic scale is simultaneously output from the sensor substrates on both sides of a certain sensor substrate. Therefore, even when the slider sequentially moves relative to stators arranged in the motor body, it is possible to continuously detect the position of the slider relative to the stators. That is, it is possible to detect the position of the mover over a wide range in the direction extending along the moving path. 
     In the linear motor according to a preferred aspect, the upstream-side position detecting unit and the downstream-side position detecting unit are constituted by two sensors, the positions of which in the moving direction are different from each other, and the position detection signal adding unit is configured to: add a position detection signal from a sensor on the upstream side in the moving direction of the downstream-side position detecting unit of the sensor substrate adjacent to the upstream side of the one sensor substrate in the moving direction and a position detection signal from a sensor on the upstream side in the moving direction of the upstream-side position detecting unit of the sensor substrate adjacent to the downstream side of the one sensor substrate; and add a position detection signal from a sensor on the downstream side in the moving direction of the downstream-side position detecting unit of the sensor substrate adjacent to the upstream side of the one sensor substrate in the moving direction and a position detection signal from a sensor on the downstream side in the moving direction of the upstream-side position detecting unit of the sensor substrate adjacent to the downstream side of the one sensor substrate. 
     In this aspect, the position detection signals from two sensors at different positions can be output as an A-phase position detection signal and a B-phase position detection signal, respectively. Further, two A-phase position detection signals output from the sensors on the upstream and downstream sides of the sensor substrate are added, and two B-phase position detection signals output from the sensors on the upstream and downstream sides of the sensor substrate are added. Therefore, even when the slider is in any of the stators arranged in the motor body, it is possible to detect the position of the slider relative to the stator more accurately. Thus, the position of the mover can be detected more accurately in a wide range in the direction extending along the moving path. 
     In the linear motor according to a preferred aspect, the linear motor further comprises a magnetic scale facing both the upstream-side position detecting unit and the downstream-side position detecting unit, wherein the magnetic scale comprises a plurality of magnets being arranged at an equal pitch to the slider so that S and N magnetic polarities alternately appear along the moving direction, a length of the magnetic scale, an arrangement of the magnets, and a distance in the moving direction between the downstream-side position detecting unit and the upstream-side position detecting unit are set such that: the sensor on the upstream side in the moving direction of the downstream-side position detecting unit of the sensor substrate adjacent to the upstream side of the one sensor substrate in the moving direction and the sensor on the upstream side in the moving direction of the upstream-side position detecting unit of the sensor substrate adjacent to the downstream side of the one sensor substrate face to respective downstream end magnets of the magnetic scale, or the sensor on the downstream side in the moving direction of the downstream-side position detecting unit of the sensor substrate adjacent to the upstream side of the one sensor substrate in the moving direction and the sensor on the downstream side in the moving direction of the upstream-side position detecting unit of the sensor substrate adjacent to the downstream side of the one sensor substrate face to respective downstream end magnets of the magnetic scale; and the magnetic polarity to which the downstream-side position detecting unit faces and the magnetic polarity to which the upstream-side position detecting unit are the same as any one of the S and N polarities, and an arrangement pitch in the moving direction of respective two sensors of the upstream-side position detecting unit and the downstream-side position detecting unit is ½ or 3/2 of an arrangement pitch of adjacent magnets of the magnetic scale, or a multiplication of the arrangement pitch by an integer multiple of 2 a length of the magnetic scale, an arrangement of the magnets, and a distance in the moving direction between the downstream-side position detecting unit and the upstream-side position detecting unit are set such that a magnetic polarity that the downstream-side position detecting unit and the upstream-side position detecting unit face is the same as any one of the S and N polarities, and an arrangement pitch in the moving direction of respective two sensors of the upstream-side position detecting unit and the downstream-side position detecting unit is ½ or 3/2 of an arrangement pitch of magnets adjacent to the magnetic scale or a multiplication of the arrangement pitch by an integer multiple of 2. 
     In this aspect, the phases of the position detection signals from the two sensors of each of the upstream-side position detecting unit and the downstream-side position detecting unit are shifted by π/2 in relation to each other, and the position of the mover can be detected more accurately. 
     In the linear motor according to a preferred aspect, the linear motor further comprises an origin sensor attached to each sensor substrate, the origin sensor being configured to detect the slider and output an origin signal that gives an origin position of the addition signal from the position detection signal adding unit. In this aspect, the position of the slider relative to the stator based on the origin position can be detected in a movement stroke range of the slider that is longer than the length of the substrate provided in the stator. 
     In the linear motor according to a preferred aspect, the origin sensor is attached to the upstream side of the sensor substrate in the moving direction. In this aspect, the origin information can be obtained immediately at the point in time when the magnetic scale of the slider starts moving from a certain stator  110  in the stator unit  100  to a stator  110  adjacent to the one stator  110 . Also the origin information can be obtained immediately at the point in time when the magnetic scale starts moving from a certain stator unit in the plurality of stator units to another stator unit adjacent to the stator unit. As a result, it is possible to detect the position of the slider in a relatively long stroke range. 
     In the linear motor according to a preferred aspect, an auxiliary sensor substrate is further provided on an upstream side of a most-upstream-side sensor substrate attached to a most-upstream-side stator in the moving direction, a downstream-side position detecting unit is provided on an upstream side of the auxiliary sensor substrate, the downstream-side position detecting unit configured to detect an upstream end of the slider when the slider is in the most-upstream-side stator, and output a position detection signal, the position detection signal adding unit of the most-upstream-side sensor substrate is configured to add a position detection signal from the downstream-side position detecting unit of the auxiliary sensor substrate and a position detection signal from the upstream-side position detecting unit of a sensor substrate adjacent to the downstream side of the most-upstream-side sensor substrate to obtain an addition signal, and the control device is configured to detect the position of the slider relative to the most-upstream-side stator based on the addition signal output from the position detection signal adding unit of the most-upstream-side sensor substrate. 
     In this aspect, when the slider is in the most-upstream-side stator in the moving direction of the slider, the control device can detect the position of the slider relative to the most-upstream-side stator. Thus, it is possible to control the slider while immediately detecting the position of the slider in the most-upstream-side stator. 
     In the linear motor according to a preferred aspect, an auxiliary sensor substrate is further provided on a downstream side of a most-downstream-side sensor substrate attached to a most-downstream-side stator in the moving direction, an upstream-side position detecting unit is provided on an upstream side of the auxiliary sensor substrate, the upstream-side position detecting unit being configured to detect a downstream end of the slider when the slider is in the most-downstream-side stator, and output a position detection signal, the position detection signal adding unit of the most-downstream-side sensor substrate is configured to add a position detection signal from the upstream-side position detecting unit of the auxiliary sensor substrate and a position detection signal from the downstream-side position detecting unit of a sensor substrate being adjacent to the upstream side of the most-downstream-side sensor substrate to obtain an addition signal, and the control device is configured to detect the position of the slider relative to the most-downstream-side stator based on the addition signal output from the position detection signal adding unit of the most-downstream-side sensor substrate. 
     In this aspect, when the slider is in the most-downstream-side stator in the moving direction of the slider, the control device can detect the position of the slider relative to the most-downstream-side stator. Thus, it is possible to control the slider while immediately detecting the position of the slider in the most-downstream-side stator. 
     In the linear motor according to a preferred aspect, the linear motor further comprises a magnetic scale facing both the upstream-side position detecting unit and the downstream-side position detecting unit, wherein the magnetic scale comprises a plurality of magnets being arranged at an equal pitch to the slider so that S and N magnetic polarities alternately appear along the moving direction, and an arrangement pitch in the moving direction of respective two sensors of the upstream-side position detecting unit and the downstream-side position detecting unit is a multiplication of an arrangement pitch of the plurality of magnets that form the magnetic scale by {n+(½)} (where n is an integer of 0 or more). In this aspect, the phases of the position detection signals from the two sensors of each of the upstream-side position detecting unit and the downstream-side position detecting unit are shifted by π/2 in relation to each other, and the position of the mover can be detected more accurately. 
     In the linear motor according to a preferred aspect, a length of the magnetic scale, an arrangement of the magnets, and a distance in the moving direction between the downstream-side position detecting unit and the upstream-side position detecting unit are set such that: when a sensor on the upstream side in the moving direction of the downstream-side position detecting unit of the sensor substrate adjacent to the upstream side of the one sensor substrate in the moving direction faces the upstream side of the magnetic scale, a sensor on the upstream side in the moving direction of the upstream-side position detecting unit of the sensor substrate adjacent to the downstream side of the one sensor substrate faces the downstream side of the magnetic scale, and a magnetic polarity of a magnet of the magnetic scale that the sensor on the upstream side in the moving direction of the downstream-side position detecting unit faces is the same as a magnetic polarity of a magnet of the magnetic scale that the sensor on the upstream side in the moving direction of the upstream-side position detecting unit faces; and when a sensor on the downstream side in the moving direction of the downstream-side position detecting unit of the sensor substrate adjacent to the upstream side of the one sensor substrate in the moving direction faces the upstream side of the magnetic scale, a sensor on the downstream side in the moving direction of the upstream-side position detecting unit of the sensor substrate adjacent to the downstream side of the one sensor substrate faces the downstream side of the magnetic scale, and the magnetic polarity of the magnet of the magnetic scale that the downstream-side position detecting unit faces is the same as the magnetic polarity of the magnet of the magnetic scale that the upstream-side position detecting unit faces. In this aspect, the position detection signal based on detection of the magnetic scale is simultaneously output from the sensor substrates on both sides of a certain sensor substrate. Therefore, even when the slider sequentially moves relative to stators arranged in the motor body, it is possible to continuously detect the position of the slider relative to the stators. That is, it is possible to detect the position of the mover over a wide range in the direction extending along the moving path. Further, the position detection signals from two sensors at different positions can be output as an A-phase position detection signal and a B-phase position detection signal, respectively. Further, two A-phase position detection signals output from the sensors on the upstream and downstream sides of the sensor substrate are added, and two B-phase position detection signals output from the sensors on the upstream and downstream sides of the sensor substrate are added. Therefore, even when the slider is in any of the stators arranged in the motor body, it is possible to detect the position of the slider relative to the stator more accurately. Thus, the position of the mover can be detected more accurately in a wide range in the direction extending along the moving path. 
     In the linear motor according to a preferred aspect, the magnets of the magnetic scale are arranged so that the magnetic polarities of both ends of the magnetic scale are the same, and when the sensor on the upstream side in the moving direction of the downstream-side position detecting unit of the sensor substrate adjacent to the upstream side of the one sensor substrate in the moving direction faces the upstream end of the magnetic scale, the sensor on the upstream side in the moving direction of the upstream-side position detecting unit of the sensor substrate adjacent to the downstream side of the one sensor substrate faces the downstream end of the magnetic scale. In this aspect, the length of the stator relative to the slider can be set to an ideal length as required for detecting the position of the slider relative to the slider in a movement stroke range of the slider that is longer than the length of the stator. 
     In the linear motor according to a preferred aspect, a plurality of stator units that comprises the motor body and the stators attached to the motor body are connected to one another. In this aspect, handling properties are improved as compared to a linear motor in which a plurality of stators is attached to one motor body and the motor body is attached to a base. 
     According to another aspect of the present disclosure, there is provided a linear conveyance device including the linear motor in which the linear motor is configured to allow a conveying article to be mounted on the slider. 
     In this aspect, when a linear motor formed by connecting stators is disassembled, or when a connection operation of adding a stator to increase the length of the linear motor, since it is not necessary to perform an operation of attaching or detaching the sensor substrate, it is possible to obtain a linear conveyance device that has good efficiency in connecting and removing operations. 
     In the linear conveyance device according to a preferred aspect, a plurality of linear motors are provided, a first circulating device circulates the slider from the other end of one linear motor of the plurality of linear motors to one end of an adjacent linear motor, the ends of the linear motors that are connected by a circulating device circulates the slider, a last circulating device that circulates the slider from one end of a last linear motor of N linear motors to the one end of the one linear motor is provided whereby a plurality of linear motors and a plurality of circulating devices form a circulation path of the slider, and one or more of the sliders moves to the circulation path. 
     For this reason, it is possible to obtain a linear conveyance device capable of circulating the slider as well as providing good efficiency in disassembling and connecting operations. 
     Besides this, various changes can naturally be made within the scope of the claims of the present disclosure. 
     INDUSTRIAL APPLICABILITY 
     The present disclosure can be used as a driving device such as a conveyor or the like that is used for automatically conveying articles.