JP7561660B2 - Linear motors and linear transport systems - Google Patents

Description

This disclosure relates to a linear motor and a linear conveying system.

A conveying system using a linear motor has the features of being able to process and assemble products on a track with high-precision positioning, and being able to control the speed of each mover, so the uses of this conveying system are expanding. In the following, the conveying system will be referred to as a "linear conveying system." A problem with linear conveying systems is that they require electromagnets to move the movers, which results in large stators and movers, and there is a demand to reduce the footprint by narrowing the pitch between the movers.

A linear transport system has been proposed that avoids contact between adjacent rollers and achieves a narrow pitch of the movers in the direction of travel by making the positions of the rollers different between the front and rear sides of the direction of travel (see, for example, Patent Document 1). A linear motor has also been proposed in which magnets for two transport lines are arranged on one frame, thereby achieving a narrow pitch of the movers between two transport lines parallel to the direction of travel (see, for example, Patent Document 2).

International Publication No. 2018/145214 Patent No. 5313561

Conventional linear conveyance systems, in which the stator has a coil and the mover has a permanent magnet, have an issue in that it is not possible to achieve a narrow stator pitch between two parallel conveyance lines. In the technology disclosed in Patent Document 1, the board that controls the current flowing through the coil is placed on the plane where the coil and the mover overlap, so when multiple conveyance lines are arranged, it is difficult to achieve a narrow stator pitch between two parallel conveyance lines. In the technology disclosed in Patent Document 2, when the stator has a coil and the mover has a permanent magnet, the coil is generally larger than the magnet, so the stator becomes large, and when multiple conveyance lines are arranged, it is difficult to achieve a narrow stator pitch between two parallel conveyance lines.

The present disclosure has been made in consideration of the above, and aims to obtain a linear motor that achieves a narrow pitch of the mover between two parallel conveyor lines.

In order to solve the above problems and achieve the object, the linear motor according to the present disclosure has a mover having a plurality of permanent magnets, a stator having a coil, a motor driver for controlling the current of the coil, and two or more parallel conveyor lines. The motor driver is not disposed in a plane including the coil and the mover . Only one coil of the stator is disposed in the middle of the two parallel conveyor lines.

The linear motor disclosed herein has the effect of realizing a narrow pitch of the mover between two parallel conveyor lines.

FIG. 1 is a plan view showing a configuration of a linear transport system according to a first embodiment; FIG. 1 is a first cross-sectional view showing a configuration of a linear transport system according to a first embodiment; FIG. 2 is a second cross-sectional view showing the configuration of the linear transport system according to the first embodiment; FIG. 3 is a third cross-sectional view showing the configuration of the linear transport system according to the first embodiment; FIG. 11 is a first cross-sectional view showing a configuration of a linear transport system according to a second embodiment; FIG. 2 is a second cross-sectional view showing the configuration of the linear transport system according to the second embodiment; FIG. 11 is a cross-sectional view showing a configuration of a linear transport system according to a third embodiment. FIG. 13 is a cross-sectional view showing a configuration of a linear transport system according to a fourth embodiment. FIG. 13 is a cross-sectional view showing a configuration of a linear transport system according to a fifth embodiment. FIG. 13 is a cross-sectional view showing a configuration of a linear transport system according to a sixth embodiment.

The linear motor and linear transport system according to the embodiment are described in detail below with reference to the drawings.

Embodiment 1.
Fig. 1 is a plan view showing the configuration of a linear transport system 1 according to the first embodiment. Fig. 1 shows the configuration of the linear transport system 1 in a schematic manner. The linear transport system 1 is a transport system having a linear motor 2. The linear motor 2 has a mover 3 and a track module 4. The linear motor 2 further has a transport line 5a and two parallel transport lines 5b and 5c continuing from the transport line 5a. That is, the linear motor 2 has two parallel transport lines 5b and 5c. In Fig. 1, the transport lines 5a, 5b, and 5c are indicated by dashed arrows.

The linear conveying system 1 further has a branching structure 6 that directs the mover 3 moving on the conveying line 5a to either the conveying line 5b or the conveying line 5c. The track module 4 has a stator 7. Although not shown in FIG. 1, the stator 7 has multiple coils.

The linear transport system 1 may be a combination of straight linear motors 2, or a combination of straight and curved linear motors 2 connected in a track shape. The branching structure 6 switches the coil to which the mover 3 is attracted by switching the attractive force from the left and right coils. The branching structure 6 may connect the transport line moved by the straight linear motor 2 to another transport line, or may branch one transport line by mechanically reconnecting the guide rails 11 when switching. The guide rails 11 are shown in FIG. 2.

The two parallel conveying lines 5b, 5c described above are the two trajectories along which the movable element 3 of the linear motor 2 moves. As described above, the branching structure 6 causes the movable element 3 moving along the conveying line 5a to proceed to either the conveying line 5b or the conveying line 5c. Even if the branching structure 6 does not exist, it is sufficient that the two conveying lines 5b, 5c are close to each other. Close to each other here means that the coils of the conveying lines 5b and 5c are so close that there is no gap between them to allow the installation of a motor driver.

As described above, the linear motor 2 has a mover 3 and a track module 4. The mover 3 is a component on the movable side, and the track module 4 is a component on the fixed side. By connecting multiple track modules 4 together, the conveying lines 5a, 5b, and 5c are formed. By moving multiple movers 3 on the conveying lines 5a, 5b, and 5c, the linear conveying system 1 is formed.

Figure 2 is a first cross-sectional view showing the configuration of the linear transport system 1 according to the first embodiment. Figure 2 is a cross-sectional view taken along the line II-II in Figure 1. More specifically, Figure 2 shows a schematic cross section perpendicular to the transport direction immediately after branching in the first embodiment. Figure 3 is a second cross-sectional view showing the configuration of the linear transport system 1 according to the first embodiment. Figure 3 is a cross-sectional view taken along the line III-III in Figure 1. More specifically, Figure 3 shows a schematic cross section perpendicular to the transport direction during transport on the two parallel transport lines 5b and 5c in the first embodiment.

The mover 3 has a roller 8, a motor magnet 9, and a scale magnet 10. The motor magnet 9 has a plurality of permanent magnets. The track module 4 has a stator 7, a guide rail 11, a motor driver 12, and a scale 13.

Figure 4 is a third cross-sectional view showing the configuration of the linear transport system 1 according to the first embodiment. Figure 4 is a view taken along the arrow IV-IV in Figure 3. More specifically, Figure 4 shows a cross section parallel to the transport direction during transport on the parallel transport lines 5b and 5c in the first embodiment. The stator 7 has multiple coils lined up in the transport direction. In Figure 4, three of the multiple coils are assigned the symbols 7a, 7b, and 7c. Specifically, one of the three coils is assigned the symbol 7a, another of the three coils is assigned the symbol 7b, and yet another of the three coils is assigned the symbol 7c. The three coils 7a, 7b, and 7c are part of the multiple coils that the stator 7 has.

The motor driver 12 controls the current flowing through each of the multiple coils in the stator 7. In other words, the motor driver 12 is a component for controlling the current in the coils. A magnetic field is generated by the current flowing through each of the multiple coils in the stator 7, and this magnetic field provides a driving force to the motor magnet 9 of the mover 3, causing the mover 3 to operate.

The motor driver 12 is a component having a board for controlling the current flowing through each of the multiple coils of the stator 7. The motor driver 12 also has the function of communicating with the scale 13, with adjacent motor drivers 12, and with a higher-level controller. In the first embodiment, the motor driver 12 is integrated with the stator 7, the guide rail 11, and the scale 13 to form the track module 4. The motor driver 12 does not have to be included in the track module 4 having the stator 7 and the scale 13.

The scale 13 is a device for measuring the position of the mover 3. The scale 13 has multiple Hall elements. In the first embodiment, the mover 3 includes a scale magnet 10 having multiple magnetic poles, and multiple Hall elements inside the scale 13 detect the position of the mover 3. The position of the mover 3 may be detected by a method using an optical system. The method for detecting the position of the mover 3 is not limited. In the first embodiment, the scale magnets 10 are attached to both sides of the mover 3, and a structure is adopted that allows the position of the mover 3 to be measured from either side when branching.

The rollers 8 and guide rails 11 are components for restricting the movement of the mover 3 so that the mover 3 does not move in any direction other than the direction of travel when moving, and the shapes of the rollers 8 and guide rails 11 are not limited to those in embodiment 1. For example, the rollers 8 may be V-rollers or flat rollers.

As described above, the motor magnet 9 has multiple permanent magnets. In FIG. 4, three of the multiple permanent magnets are assigned the reference symbols 9a, 9b, and 9c. Specifically, one of the three permanent magnets is assigned the reference symbol 9a, another of the three permanent magnets is assigned the reference symbol 9b, and yet another of the three permanent magnets is assigned the reference symbol 9c. The three permanent magnets 9a, 9b, and 9c are part of the multiple permanent magnets that the motor magnet 9 has.

The multiple permanent magnets have south and north poles arranged alternately in the direction of travel, and the motor magnet 9 receives a magnetic field from the multiple coils of the stator 7 to generate a propulsive force. In the first embodiment, the mover 3 also has a motor magnet 9 on the side opposite to the mounting surface of one of the motor magnets 9. This allows the mover 3 to receive a propulsive force from the coils from either side when branching.

In the first embodiment, the motor driver 12 is arranged vertically below the surface where the coils of the stators 7 of the two parallel conveyor lines 5b and 5c and the motor magnets 9 of the mover 3 overlap. In other words, in the first embodiment, the motor driver 12, which is conventionally arranged next to the motor magnet 9, is not next to the motor magnet 9. Therefore, the parallel conveyor lines 5b and 5c can be installed right next to the motor magnet 9. This makes it possible to save space in the installation area of the conveyor path and to reduce the size of the processing machine when processing on the track. The installation position of the motor driver 12 does not have to be the position of the first embodiment, as long as it is other than the surface where the coils and the motor magnets 9 overlap.

The board for controlling the current flowing through the coil of the linear motor 2 according to the first embodiment is placed on a plane other than the plane where the coil and the mover 3 overlap. In other words, the motor driver 12 is not placed in the plane that includes the coil and the mover 3. This allows the linear motor 2 to achieve a narrow pitch for the mover 3 between the two parallel conveyor lines 5b, 5c. The above plane is a plane that is horizontal to the direction in which the mover 3 moves, for example the plane of line IV-IV in FIG. 3.

In the first embodiment, the linear motor 2 has a structure in which the mover 3 has a permanent magnet and the stator 7 has a coil. This structure has the advantage that, compared to a structure in which the mover 3 has a coil and the stator 7 has a permanent magnet, it is possible to realize a smaller mover 3, and wiring to the mover 3 is not required, so the movement of the mover 3 is not restricted by wiring.

Embodiment 2.
FIG. 5 is a first cross-sectional view showing the configuration of a linear transport system according to the second embodiment. FIG. 5 is a view corresponding to the view taken along the line III-III in FIG. 1. More specifically, FIG. 5 is a schematic view of a cross section perpendicular to the transport direction during transport on the parallel transport lines 5b and 5c in the second embodiment. FIG. 6 is a second cross-sectional view showing the configuration of a linear transport system according to the second embodiment. FIG. 6 is a view taken along the line VI-VI in FIG. More specifically, FIG. 6 is a schematic view of a cross section parallel to the transport direction during transport on the parallel transport lines 5b and 5c in the second embodiment. In the second embodiment, differences from the first embodiment will be mainly described.

The linear transport system according to the second embodiment has two parallel transport lines 5b and 5c, similar to the linear transport system 1 according to the first embodiment. In the second embodiment, too, the board for controlling the current flowing through the coil of the linear motor 2 is placed outside the plane where the coil and the mover 3 overlap. In the second embodiment, only one coil of the stator 7 is placed midway between the two parallel transport lines 5b and 5c.

The stator 7, which is disposed between the two parallel conveyor lines 5b and 5c, has one coil, which is capable of generating a magnetic field for both conveyor lines 5b and 5c. For example, the coil can simultaneously generate a magnetic field that is a north pole for conveyor line 5b and a magnetic field that is a south pole for conveyor line 5c.

According to the configuration of embodiment 2, one coil can drive two conveyor lines 5b, 5c, so the distance between the two conveyor lines 5b, 5c can be shortened, which saves space on the installation area of the conveyor path and makes it possible to miniaturize the processing machine when processing on the track. In addition, according to the configuration of embodiment 2, the number of stators 7 is reduced by half compared to when a stator 7 is installed on each of the two conveyor lines 5b, 5c, making it possible to reduce costs.

Embodiment 3.
Fig. 7 is a cross-sectional view showing the configuration of a linear transport system according to embodiment 3. Fig. 7 is a view corresponding to the arrow view of line VI-VI in Fig. 5. More specifically, Fig. 7 shows a schematic cross section parallel to the transport direction during transport on parallel transport lines 5b and 5c in embodiment 3. In embodiment 3, differences from embodiment 2 will be mainly described.

The linear transport system according to the third embodiment has two parallel transport lines 5b and 5c. A board for controlling the current flowing through the coil of the linear motor 2 is placed on a plane other than the plane where the coil and the mover 3 overlap. Only one stator 7 is placed between the two parallel transport lines 5b and 5c. The linear motor 2 according to the third embodiment has two types of movers 3 with different pole arrangements of multiple permanent magnets.

The linear transport system according to the third embodiment is characterized in that the transport lines 5b and 5c are used differently depending on the type of pole arrangement. The pole arrangement refers to the arrangement of the south and north poles of the multiple permanent magnets held by the mover 3. The south and north poles of the permanent magnets are arranged alternately in the direction of travel of the mover 3. The linear motor 2 according to the third embodiment has two types of movers 3: movers 3 in which the permanent magnet is arranged from the south pole to the direction of travel, and movers 3 in which the permanent magnet is arranged from the north pole to the direction of travel.

The use of conveyor lines 5b and 5c depending on the type of pole arrangement described above means dividing conveyor lines 5b and 5c into conveyor lines through which movers 3 in which permanent magnets are arranged starting from the south pole flow and conveyor lines through which movers 3 in which permanent magnets are arranged starting from the north pole flow.

According to the configuration of embodiment 3, when one coil arranged in the center of two parallel conveyor lines 5b, 5c simultaneously operates the movers 3 of the two conveyor lines 5b, 5c, for example, one coil generates a magnetic field that becomes a south pole on the conveyor line 5b and a magnetic field that becomes a north pole on the conveyor line 5c. Therefore, by placing one of the two movers 3 with different pole arrangements on the conveyor line 5b and the other of the two movers 3 on the conveyor line 5c, it becomes possible to align the positions of the two movers 3 in the traveling direction without misalignment by one magnetic pole.

Embodiment 4.
Fig. 8 is a cross-sectional view showing the configuration of a linear transport system according to embodiment 4. Fig. 8 is a view corresponding to the arrow view of line VI-VI in Fig. 5. More specifically, Fig. 8 shows a schematic cross section parallel to the transport direction during transport on parallel transport lines 5b and 5c in embodiment 4. In embodiment 4, differences from embodiment 3 will be mainly described.

The linear transport system according to the fourth embodiment has two parallel transport lines 5b and 5c. The board for controlling the current flowing through the coil of the linear motor 2 is placed on a plane other than the plane where the coil and the mover 3 overlap. Only one stator 7 is placed between the two parallel transport lines 5b and 5c.

The linear motor 2 according to the fourth embodiment has a mover 3 in which the pole arrangement of the multiple permanent magnets arranged on the surface on the stator 7 side is different from the pole arrangement of the multiple permanent magnets arranged on the surface on the guide rail 11 side. In other words, the pole arrangement of the multiple permanent magnets arranged on the surface of the mover 3 on the stator 7 side is shifted by one magnetic pole from the pole arrangement of the multiple permanent magnets arranged on the surface of the mover 3 opposite to the above-mentioned surface. The above-mentioned surface and the opposite surface are parallel.

The pole arrangement refers to the arrangement of the south and north poles of the multiple permanent magnets that the mover 3 has. The south and north poles of the multiple permanent magnets are arranged alternately in the direction of travel of the mover 3. The mover 3 of embodiment 4 has a surface on which the permanent magnets are arranged starting from the south pole in the direction of travel, and a surface on which the permanent magnets are arranged starting from the north pole.

According to the configuration of embodiment 4, when one coil arranged at the center of two parallel conveyor lines 5b, 5c simultaneously operates the movers 3 of each of the two conveyor lines 5b, 5c, for example, one coil generates a magnetic field that becomes an S pole on the conveyor line 5b and a magnetic field that becomes an N pole on the conveyor line 5c. Therefore, by arranging one of the two movers 3 with different pole arrangements on the conveyor line 5b and the other of the two movers 3 on the conveyor line 5c, it is possible to align the positions of the two movers 3 in the traveling direction without misalignment by one magnetic pole. In addition, compared to the configuration of embodiment 3, in the configuration of embodiment 4, there is only one type of mover 3, so the types and number of movers 3 can be reduced, which in turn makes it possible to realize cost reduction.

Embodiment 5.
Fig. 9 is a cross-sectional view showing the configuration of a linear transport system according to embodiment 5. Fig. 9 is a view corresponding to the view seen from the arrows along line II-II in Fig. 1. More specifically, Fig. 9 shows a schematic cross section perpendicular to the transport direction during transport on parallel transport lines 5b and 5c in embodiment 5. In embodiment 5, differences from embodiments 1 to 3 will be mainly described.

In embodiment 5, the mover 3 has only one scale magnet 10, and the position of the scale magnet 10 can be measured from either the left or right track module 4. In embodiment 5, the scale 13 is arranged horizontally relative to the scale magnet 10, but as long as the position can be measured from either the left or right track module 4, the scale 13 may be arranged vertically relative to the scale magnet 10.

According to the structure of embodiment 5, the mover 3 only needs to have one scale magnet 10, making it possible to reduce the size and cost of the mover 3.

Embodiment 6.
10 is a cross-sectional view showing the configuration of a linear conveyance system according to a sixth embodiment. The linear conveyance system according to the sixth embodiment has two or more parallel conveyance lines. A board for controlling the current flowing through the coil of the linear motor 2 is arranged on a plane other than the plane on which the coil and the mover 3 overlap. When the number of conveyance lines is M, when M is an even number, M/2 stators 7 are arranged on a plane perpendicular to the traveling direction of the two or more parallel conveyance lines, and when M is an odd number, (M+1)/2 stators 7 are arranged on a plane perpendicular to the traveling direction of the two or more parallel conveyance lines. M is an integer of 2 or more. The traveling direction is the traveling direction of the mover 3. In the mover 3, the pole arrangement of the permanent magnets arranged on the surface on the side of the stator 7 is different from the pole arrangement of the permanent magnets arranged on the surface on the side of the guide rail 11.

According to the structure of embodiment 6, it is possible to narrow the pitch between multiple parallel conveying lines, which makes it possible to reduce the space required for conveying lines and miniaturize the equipment in lines for performing batch processing and bulk processing in processing, and also makes it possible to reduce the space required for waiting while the movable element 3 is waiting.

The configurations shown in the above embodiments are merely examples, and may be combined with other known technologies, or the embodiments may be combined with each other. In addition, parts of the configurations may be omitted or modified without departing from the spirit of the invention.

1 Linear conveying system, 2 Linear motor, 3 Movable element, 4 Track module, 5a, 5b, 5c Conveying line, 6 Branch structure, 7 Stator, 7a, 7b, 7c Coil, 8 Roller, 9 Motor magnet, 9a, 9b, 9c Permanent magnet, 10 Scale magnet, 11 Guide rail, 12 Motor driver, 13 Scale.

Claims (6)

A mover having a plurality of permanent magnets;
a stator having a coil;
a motor driver for controlling a current in the coil;
two or more parallel conveying lines;
The motor driver is not disposed within a plane including the coil and the mover,
Only one of the coils of the stator is disposed between the two parallel conveying lines.
A linear motor characterized by: 2. The linear motor according to claim 1, further comprising a second mover having a plurality of permanent magnets with a pole arrangement different from the pole arrangement of the plurality of permanent magnets of the mover. 2. The linear motor according to claim 1, wherein the pole arrangement of the plurality of permanent magnets arranged on the surface of the mover facing the stator is shifted by one magnetic pole from the pole arrangement of the plurality of permanent magnets arranged on the surface of the mover opposite to the surface of the mover. 3. The linear motor according to claim 1, wherein the mover has only one scale magnet. When the number of the two or more parallel transport lines is M, when M is an even number, M/2 of the stators are arranged on a plane perpendicular to the traveling direction of the two or more parallel transport lines, and when M is an odd number, (M+1)/2 of the stators are arranged on a plane perpendicular to the traveling direction of the two or more parallel transport lines;
M is an integer of 2 or more,
The linear motor according to claim 1 , wherein the moving direction is a moving direction of the mover . A linear transport system comprising the linear motor according to any one of claims 1 to 5 .

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