JP7503833B2 - Multi-axis linear motor actuator - Google Patents

Description

The present invention relates to a multi-axis linear motor actuator, and in particular to a multi-axis linear motor actuator suitable for a multi-axis type dispensing device.

One type of linear motor is called a linear shaft motor. A linear shaft motor has a coil section made of multiple cylindrical coils stacked in the direction of their central axis, and a magnet section made of multiple permanent magnets connected in series with the same magnetic poles facing each other and fixed to a support member longer than the connected permanent magnets to form a motor shaft, with a small gap in the center hole of the coil section through which the motor shaft is inserted. The multiple coils are divided into three phases, U-phase, V-phase, and W-phase, and AC currents with a phase shift of 120 degrees are passed through the coils of each phase, so that the magnetic field generated by the permanent magnets and the current passed through the coils work together to generate a thrust that drives the motor shaft in the direction of the central axis (Patent Document 1).

Such linear shaft motors are applied in a variety of fields, including handling devices for electronic components and dispensing devices that aspirate and dispense small amounts of liquid. In both handling devices and dispensing devices, the motor shaft of the linear shaft motor is usually used as the first shaft, and a hollow second shaft is combined with this first shaft in a direction parallel to its central axis so as to move up and down integrally with the first shaft, forming a linear motor actuator. The hollow space in the second shaft is configured so that it can be used for handling with air and for aspirating and dispensing liquid.

For example, in the case of a handling device, a tool such as a vacuum suction device is attached to the tip of the second shaft, and electronic components are handled in synchronization with the up and down movement of the first shaft (Patent Document 2). On the other hand, in the case of a dispensing device, a nozzle is attached to the tip of the second shaft to serve as a dispensing head, and liquid is sucked in and discharged by appropriately increasing and decreasing the internal pressure of the nozzle in synchronization with the up and down movement of the first shaft.

JP 2017-139861 A JP 2012-090492 A

In recent years, what is called a multi-axis linear motor actuator has been provided, in which multiple sets of linear motor actuators formed by combining a first shaft and a second shaft as described above are arranged in a row and configured to perform the same work operation collectively, thereby improving work efficiency. For example, a multi-axis linear motor actuator is configured by arranging multiple sets of the above-mentioned individually manufactured dispensing devices in a row, and is used as a multi-axis dispensing device for dispensing work in various fields such as pharmaceuticals, cosmetics, and biology. With a multi-axis dispensing device, multiple sets of dispensing devices are configured to perform the same work operation collectively, which is effective in significantly reducing labor compared to manual dispensing work and preventing dispensing errors.

When a conventional multi-axis dispensing device is combined with a microplate for 96 specimens (8 samples x 12 rows) as a clinical testing device, for example, eight sets of dispensing devices are assembled in a row to form an eight-axis simultaneous control type, i.e., a multi-axis dispensing device. The multi-axis dispensing device is then configured to move back and forth between the liquid (e.g., reagent) suction location and the discharge location (i.e., the microplate) by a transport mechanism. Thus, conventional multi-axis dispensing devices are generally manufactured by combining multiple sets of dispensing devices that are manufactured individually, and are only capable of dispensing the same amount of reagent into the microplate at the same time.

However, previous multi-axis dispensing devices, which consisted of a linear motor actuator made by combining a first shaft (linear shaft motor) and a second shaft and then combining multiple sets of these, had the problem that the entire device was large and it was difficult to meet the demand for compactness.

On the other hand, there is an increasing demand for multi-axis dispensing devices that allow multiple sets of dispensing devices to be controlled independently. With a multi-axis independently controlled dispensing device, even if the same row is used, each axis can eject a different amount of reagent onto a microplate at a different timing, allowing the reaction of the specimen to be monitored. In other words, the amount and timing of reagent ejection onto the microplate can be set for each sample, and the suction and ejection of reagent can be performed in an automated controlled form, resulting in objective and highly reliable test results.

In view of the above problems, the objective of the present invention is to provide a multi-axis linear motor actuator that is suitable for compact size.

(First aspect)
A first aspect of the present invention is a multi-axis linear motor actuator including n combinations (n is a positive even number) of a linear shaft motor having a motor shaft driven in a central axis direction, and an axially shaped driven body extending parallel to the linear shaft motor and connected to at least one end side of the motor shaft by a first connecting member so as to be displaced integrally with the motor shaft,
a first motor unit and a second motor unit, each of which includes a first motor housing member and a second motor housing member, the first motor housing member and the second motor housing member housing the first motor unit and the second motor unit, the first motor unit and the second motor unit housing the second motor unit, the first motor unit and the second motor unit housing the second motor unit,
a first and a second driven body support member which have n/2 sets of guide portions and support the driven body in a state where the driven body is aligned in a line in a plan view so as to be movable in a central axial direction, and which are combined with the first and second motor units, respectively ;
This is a multi-axis linear motor actuator characterized in that the first and second motor units are opposed to each other with the first and second driven body support members sandwiched between them , and the arrangement of the n/2 linear shaft motors in the first motor unit and the arrangement of the n/2 linear shaft motors in the second motor unit are combined so as to be staggered in a planar view, and the guide portions of the first driven body support member and the guide portions of the second driven body support member are adjacent to each other in a planar view and are alternately arranged above and below .

(Second Aspect)
In a second aspect of the present invention, the n/2 sets of guide parts installed on the second driven body support member combined with the second motor unit are guide parts for n/2 driven bodies connected to respective motor shafts of the n/2 linear shaft motors in the first motor unit,
The multi-axis linear motor actuator according to the first aspect described above is characterized in that the n/2 sets of guide portions installed on the first driven body support member combined with the first motor unit are guide portions for n/2 driven bodies connected to respective motor shafts of the n/2 linear shaft motors in the second motor unit.

(Third Aspect)
In a third aspect of the present invention, the n/2 sets of guide parts installed on the first driven body support member combined with the first motor unit are guide parts for n/2 driven bodies connected to respective motor shafts of the n/2 linear shaft motors in the first motor unit,
The multi-axis linear motor actuator according to the first aspect above is characterized in that the n/2 sets of guide portions installed on the second driven body support member combined with the second motor unit are guide portions for n/2 driven bodies connected to the respective motor shafts of the n/2 linear shaft motors in the second motor unit.

(Fourth aspect)
In a fourth aspect of the present invention, the first driven body support member has two first mounting parts attached to a surface of the first motor unit facing the second motor unit, and a first bridge part that is bridged between the two first mounting parts and is used to install n/2 guide parts, and the first bridge part has n/2 sets of protruding parts that protrude toward the second motor unit and have holes for passing the driven body therethrough,
the second driven body support member has two second mounting portions attached to a surface of the second motor unit facing the first motor unit, and a second bridge portion spanning between the two second mounting portions for installing the n/2 guide portions, the second bridge portion having n/2 sets of protruding portions protruding toward the first motor unit and having holes for passing the driven bodies therethrough;
This is a multi-axis linear motor actuator according to any one of the first to third aspects, characterized in that the guide portions of the first and second driven body support members are respectively installed on the protruding portions with insertion holes, through which the driven body is inserted, mating with holes in the protruding portions and protruding from the first and second bridge portions, so that the insertion holes of the guide portion of the first driven body support member and the insertion holes of the guide portion of the second driven body support member are adjacent to each other in a row and alternately in a planar view.

(Fifth aspect)
In a fifth aspect of the present invention, the first driven body support member has an upper bridge having n/2 upper protrusions and a lower bridge having n/2 lower protrusions as the first bridge portion, which are positioned to overlap each other in a plan view, and n/2 upper guides and n/2 lower guides are installed on the n/2 upper protrusions and the n/2 lower protrusions, respectively, as the n/2 sets of guide portions,
The second driven body support member also has an upper bridge having n/2 upper protrusions and a lower bridge having n/2 lower protrusions as the second bridge portion, which are positioned so as to overlap each other in a plan view, and n/2 upper guides and n/2 lower guides are installed on the n/2 upper protrusions and the n/2 lower protrusions, respectively, as the n/2 sets of guide portions,
A multi-axis linear motor actuator according to any one of the first to fourth aspects, characterized in that the upper bridge of the first driven body support member is at a higher or lower height position than the upper bridge of the second driven body support member, and the lower bridge of the first driven body support member is also at a higher or lower height position than the lower bridge of the second driven body support member.

(Sixth Aspect)
In a sixth aspect of the present invention, the upper guide of the first driven body support member is installed on the upper surface side of the upper bridge, and the lower guide is installed on the lower surface side of the lower bridge,
This is a multi-axis linear motor actuator described in any one of claims 1 to 5, characterized in that the upper guide of the second driven body support member is installed on the upper surface side of the upper bridge, and the lower guide is installed on the lower surface side of the lower bridge.

(Seventh aspect)
A seventh aspect of the present invention is the multi-axis linear motor actuator according to any one of the fourth to sixth aspects, characterized in that the length of the guide portions in the arrangement direction of the first driven body support member and the second driven body support member is made longer than the length of the linear shaft motors in the arrangement direction of the first motor unit and the second motor unit, the two first mounting portions of the first driven body support member and the two second mounting portions of the second driven body support member are made to protrude from both ends of the first motor unit and the second motor unit in the arrangement direction, and the first driven body support member and the second driven body support member are fixed at the protruding portions.

The present invention provides a multi-axis linear motor actuator that is suitable for compact design.

FIG. 1 is a perspective view of an eight-axis dispensing device which is a preferred embodiment of a multi-axis linear motor actuator according to the present invention. FIG. 2 is a perspective view showing a linear shaft motor, a dispensing head, and upper and lower connecting members connecting them, extracted from the eight-axis dispensing device shown in FIG. 1 . FIG. 2 is a perspective view showing a combination of four linear shaft motors and dispensing heads (four-axis dispensing device) on the left side of the eight-axis dispensing device shown in FIG. 1 . 2 is a longitudinal sectional view taken along line AA in FIG. 1. FIG. 5 is a side view showing the combination of the linear shaft motor and the dispensing head and the upper and lower connecting members connecting them, extracted from FIG. 4 . 5 is a cross-sectional view showing a part of the internal structure of the linear shaft motor shown in FIG. 4 and a part of a circuit board installed in a motor unit. FIG. 5 is a longitudinal sectional view of the main part of the dispensing head shown in FIG. 4 . 2 is an exploded perspective view of the first and second motor units and the first and second dispensing head support members of the eight-axis dispensing device shown in FIG. 1 , with the linear shaft motors and dispensing heads omitted. FIG. 2A to 2C are perspective views for sequentially explaining a manufacturing process of a coil unit which is a main part of the first and second motor units in the eight-axis dispensing device shown in FIG. 10 is a perspective view of a coil portion which is a component of the coil unit shown in FIG. 9 . FIG. 10 is a perspective view showing the coil unit shown in FIG. 9 , with a part thereof disassembled. 9 is a diagram showing an example of a circuit board attached to the coil unit shown in FIG. 8 . FIG. 9 is a perspective view of the first motor unit on the left side of the pair of motor units shown in FIG. 8, with the motor shaft of the linear shaft motor omitted, as viewed from a different angle. 1 is a diagram for explaining the mounting interval of a pair of Hall sensors installed for position control in a linear shaft motor. FIG. FIG. 11 is a diagram showing the results of measuring an external magnetic field in the radial direction of a motor shaft in a linear shaft motor. FIG. 1 is a block diagram showing the configuration of a position control system for a linear shaft motor using a Hall sensor. 2 is a top view showing an arrangement of upper connecting members in the eight-shaft dispensing device shown in FIG. 1. FIG. FIG. 2 is a plan view of the eight-axis dispensing device shown in FIG. 1 viewed from above with the upper connecting member, linear shaft motor, and dispensing head omitted, showing a first dispensing head support member attached to a first motor unit and a second dispensing head support member attached to a second motor unit in a separated state. 19 is a plan view showing the first and second dispensing head support members shown in FIG. 18 in a coupled state; FIG. 9A and 9B show the first dispensing head support member shown in FIG. 8, in which FIG. 9A is a top view and FIG. 9B is a front view. 9A and 9B show the second dispensing head support member shown in FIG. 8, with FIG. 9A being a top view and FIG. 9B being a front view. 13 is a perspective view showing a state in which a first dispensing head support member supporting four head bodies and a second dispensing head support member supporting four head bodies are butted together and fixed. FIG. FIG. 23 is a front view of FIG. 22. 13 is a plan view showing another example of a connecting configuration between the first dispensing head support member and the second dispensing head support member. FIG. 13 is a plan view showing yet another example of a connecting configuration between the first dispensing head support member and the second dispensing head support member. FIG. FIG. 19 shows a second embodiment of the present invention, and is a plan view of an eight-axis dispensing device as seen from above, with the upper connecting member, linear shaft motor, and dispensing head omitted, similar to FIG. 18, and shows a first dispensing head support member attached to the first motor unit and a second dispensing head support member attached to the second motor unit in a separated state. FIG. 2 is a perspective view for explaining a detection means for detecting an upward movement position of an upper connecting member in the eight-axis independently controlled dispensing device shown in FIG. 1 . FIG. 28 is a diagram for explaining an example of an installation form of the detection means shown in FIG. 27 .

With reference to Figures 1 to 8, an eight-axis dispensing device will be described as a preferred embodiment of a multi-axis linear motor actuator according to the present invention.

Figures 1 and 2 show an eight-axis dispensing device to which the present invention is applied, and Figure 3 shows half of the eight-axis dispensing device, i.e., a four-axis dispensing device. Figure 4 is a vertical cross-sectional view taken along line A-A in Figure 1. Figure 5 is a side view showing the combination of the linear shaft motor and dispensing head and the upper and lower connecting members that connect them, extracted from Figure 4. Also, Figure 6 is a cross-sectional view showing the internal structure of part of the linear shaft motor and part of the circuit board installed in the motor unit.

First, we will explain the internal structure of a linear shaft motor, but since this type of linear shaft motor is well known, we will only provide a brief explanation.

Referring to FIG. 6, the linear shaft motor 10 has a motor shaft (first shaft) 11 in which a plurality of permanent magnets 12 magnetized in the central axis direction are connected in series with the same magnetic poles facing each other and housed and fixed in a cylindrical body 13 made of a non-magnetic material. The cylindrical body 13 has a length equal to or longer than the total length of the plurality of permanent magnets 12. The cylindrical body 13 portion housing the permanent magnets 12 may be called the magnet section for the linear shaft motor 10. As described later, such a magnet section faces the permanent magnets 12 of the same shape and magnetic force, so that N poles and S poles appear alternately at the same pitch in the axial direction around the motor shaft 11 (magnet section), and the surface magnetic flux density is measured to form a sinusoidal waveform. The linear shaft motor 10 also has a coil section 15 in which a plurality of cylindrical coils 14 are connected in series so as to concentrically contain the motor shaft 11 through a gap. The coil section 15 is integrated by connecting multiple cylindrical coils 14 in series on the outer periphery of a resin coil-integrated tube 16. The coil-integrated tube 16 has an inner diameter represented by (the outer diameter of the tube 13 + the gap). The motor shaft 11 and the coil section 15 are configured to be relatively movable in the central axis direction, but here, the motor shaft 11 is configured as the movable part and the coil section 15 as the fixed part.

The coil section 15 is made up of at least three coils 14, one for U-phase, one for V-phase, and one for W-phase, to form a three-phase linear motor. An alternating current with an electrical phase difference of 120 degrees flows through each coil 14, and by controlling the current flowing through each coil 14, the magnetic field generated by the permanent magnet 12 and the current flowing through the coil 14 interact to generate a thrust that drives the motor shaft 11 in the central axial direction.

In this specification, "connecting permanent magnets" does not only mean directly connecting the permanent magnets 12 together as shown in FIG. 6, but also includes connecting adjacent permanent magnets 12 by placing a soft magnetic material such as soft iron or another permanent magnet magnetized in the radial direction as a pole piece between them, taking into consideration the magnetic properties and the manufacturing process of suppressing repulsive forces to make assembly easier.

The linear motor drive circuit, including the power supply, and the linear motor control circuit are well known and are not essential to the present invention, so illustrations and explanations of the circuits will be omitted and the position control system will be explained later.

Referring to Figures 4 and 5, in the linear shaft motor 10, a lower connecting member 31 and an upper connecting member 32 are fixed to the lower and upper sides, respectively, of the motor shaft 11. Therefore, as the motor shaft 11 moves up and down relative to the coil portion 15 as a fixed portion, the lower connecting member 31 and the upper connecting member 32 also move up and down integrally.

A dispensing head (a cylindrical driven body) 40 is attached to the lower connecting member 31 and the upper connecting member 32 in parallel with the central axis of the motor shaft 11. The dispensing head 40 has a head body 41 made of a hollow cylindrical body having a length longer than the distance between the lower connecting member 31 and the upper connecting member 32, as shown in FIG. 7, and the upper end of the head body 41 has a protrusion 41-1 that protrudes slightly from the upper connecting member 32. On the other hand, a nozzle part 43 with a tip 42 attached to its tip is attached to the lower part of the head body 41 protruding from the lower connecting member 31. The dispensing head 40 moves up and down together with the motor shaft 11 via the lower connecting member 31 and the upper connecting member 32. The dispensing head 40 is structured so that the part above the nozzle part 43, i.e., the head body 41, is used as a spline shaft to prevent rotation around its central axis. That is, a spline groove (or ridge) extending in the direction of the central axis is provided on the outer periphery of the head body 41, which serves as the spline shaft.

Returning to Figures 4 and 5, an upper guide 44-1 and a lower guide 44-2 having a splined outer cylinder with a flange that constitute a ball spline are provided as guide parts at two locations between the lower connecting member 31 and the upper connecting member 32. The upper guide 44-1 and the lower guide 44-2 each have a splined outer cylinder with a through hole 44-1a (the lower through hole is not shown) in their center for inserting the head body 41 of the dispensing head 40, and a protrusion (or groove) extending in the central axis direction is formed on the inner periphery of the through hole to constitute a ball spline together with the spline groove (or protrusion) of the head body 41. The head body 41 is attached to the upper guide 44-1 and the lower guide 44-2 so that the spline groove (or protrusion) fits into the protrusion (or groove). Note that a ball bush may be used instead of the ball spline. Additionally, the guide portion 44 may be realized by only one of the upper guide 44-1 and the lower guide 44-2.

The upper guide 44-1 and the lower guide 44-2 are installed on the dispensing head support member (driven body support member) and function as a set of guide parts 44, but this embodiment has one feature in the installation form of the upper guide 44-1 and the lower guide 44-2, which will be described in detail later.

In order to fix the upper end of the motor shaft 11 to the upper connecting member 32, in this embodiment, as shown in FIG. 1, a through hole 32a for inserting the motor shaft 11 is formed in the upper connecting member 32, and a slot 32b is formed from the through hole 32a to one end of the upper connecting member 32. Furthermore, a hexagonal socket head screw 34 can be screwed into the one end of the upper connecting member 32, passing from one side across the slot 32b toward the other side. With this structure, the upper end of the motor shaft 11 inserted into the through hole 32a is fixed in the through hole 32a by tightening the hexagonal socket head screw 34.

The same fixing structure as above is also applied to the lower end side of the motor shaft 11. That is, referring also to Figures 2 and 5, the lower end of the motor shaft 11 inserted into the through hole 31a formed in the lower connecting member 31 is fixed in the through hole 31a by tightening with the hexagon socket head screw 35.

As shown in FIG. 3, the same fixing structure (a combination of a through hole, a slot, and a hexagon socket head screw) as described above is applied to the upper end side of the head body 41 and the middle part of the head body 41 slightly above the nozzle part 43, so that the head body 41 is fixed in the through hole 32c of the upper connecting member 32 and in the through hole 31c of the lower connecting member 31 by tightening with the hexagon socket head screws 36 and 37.

As can be seen from FIG. 3, the four-axis dispensing device is made up of four combinations of linear shaft motors 10 and dispensing heads 40, with the four linear shaft motors 10 and the four dispensing heads 40 each combined so that they are aligned in a row in different planes that are parallel to each other.

Figure 8 is an exploded perspective view of the first and second motor units 50A, 50B and the first and second dispensing head support members (driven body support members) 60A, 60B in the 8-axis dispensing device shown in Figure 1, with the linear shaft motors and dispensing heads omitted. Since the first and second motor units 50A, 50B have substantially the same structure, the following description of the motor units will mainly focus on the first motor unit 50A on the left side of Figure 8.

4 and 8, a pair of coil fixing members (motor housing members) 50 are used to arrange eight linear shaft motors 10 in a row of four each. On the other hand, first and second dispensing head support members 60A and 60B are used to arrange eight dispensing heads 40 in a row. As will be clear from the following description, in this embodiment, the four dispensing heads 40 supported by the first motor unit 50A and the second dispensing head support member 60B constitute one of the pair of four-axis dispensing devices, and the four dispensing heads 40 supported by the second motor unit 50B and the first dispensing head support member 60A constitute the other of the pair of four-axis dispensing devices. The first and second dispensing head support members 60A and 60B each have four sets of guide parts 44 for supporting the four dispensing heads 40 of the other four-axis dispensing device of the pair and the four dispensing heads 40 of the other four-axis dispensing device of the pair in an alternating arrangement. As described below, the guide parts 44 have a splined outer cylinder of a ball spline to form a means for supporting the dispensing heads 40 so that they can move in the central axis direction while preventing rotation around the central axis.

The four-axis dispensing device shown in Figure 3 is assembled as follows. However, the four-axis dispensing device shown in Figure 3 is a partially omitted diagram for ease of explanation, and is not manufactured in the form shown in Figure 3. This is because the four dispensing heads 40 shown in Figure 3 are incorporated into the eight-axis dispensing device while being supported by the second dispensing head support member 60B described above.

First, the four coil parts 15 are arranged and fixed at regular intervals in the coil fixing member 50, and then the motor shaft 11 is inserted into each coil part 15. Next, the lower connecting member 31 and the upper connecting member 32 are fixed to the lower end and upper end of each motor shaft 11, respectively. Next, the four dispensing heads 40 without the tips 42 and nozzles 43 are supported by the four sets of guide parts 44 of the second dispensing head support member 60B, and the lower part of the head body 41 is fixed to the lower connecting member 31, and the upper end side of the head body 41 is fixed to the upper connecting member 32. Then, the nozzle 43 and the tip 42 are attached to the head body 41. In this manner, one of the pair of four-axis dispensing devices is assembled, and the other of the pair of four-axis dispensing devices is assembled in the same manner. When assembling the pair of four-axis dispensing devices, the first dispensing head support member 60A and the second dispensing head support member 60B are joined so that the four sets of guide portions 44 of the first dispensing head support member 60A and the four sets of guide portions 44 of the second dispensing head support member 60B are alternately aligned in a row, resulting in an eight-axis dispensing device as shown in FIG. 1.

With reference to Figures 9 to 13, we will explain the coil unit manufacturing method, which is another feature of this embodiment, by applying it to the first motor unit 50A.

Figure 9 is a perspective view showing the manufacturing process for the coil unit of a four-axis dispensing device step by step.

In FIG. 9, first, a coil fixing member (first motor housing member) 50 is prepared, which has a receiving portion 51 capable of receiving four sets of coil portions 15 arranged in a row at a predetermined pitch P1 (FIG. 9(a)). Referring also to FIG. 10, the coil portion 15 is formed by connecting and fixing a plurality of coils 14 in series to the outer periphery of a resin coil integrated tube 16. The coil integrated tube 16 has an inner diameter slightly larger than the outer diameter of the motor shaft 11, and a length that includes protruding portions 16-1 protruding from both ends of the coils 14 among the plurality of coils. As described above, the plurality of coils 14 are arranged in groups of three, U-phase, V-phase, and W-phase, and are delta- or star-connected.

Next, as shown in FIG. 9(b), the four sets of coil parts 15 are arranged in a row at a predetermined pitch P1 in the receiving part 51 of the coil fixing member 50.

Referring to FIG. 11, the receiving portion 51 of the coil fixing member 50 is formed by a bottom wall 51a that defines the bottom surface of the receiving space for the four coil parts 15 arranged in a row, a pair of wall members 51b that face each other so as to define the receiving space in a direction parallel to the axial direction of the coil parts 15, and a pair of coil ends 52 provided between the pair of wall members 51b at both ends of the four coil parts 15. The coil ends 52 have four through holes 52a into which the protruding parts 16-1 of the coil integrated tube 16 protruding from both ends of the four coil parts 15 are inserted, and are removably fixed to the bottom wall 51a by screws. It is desirable that the protruding length of the protruding parts 16-1 is shorter than the plate thickness of the coil ends 52, i.e., the length of the through holes 52a.

The coil ends 52 are removable from the bottom wall 51a because the total length of the multiple coils 14 is approximately the same as the spacing between the pair of coil ends 52. In other words, as shown in FIG. 11, one of the protruding parts 16-1 of the four coil parts 15 is inserted into the four through holes 52a of one coil end 52 fixed to the bottom wall 51a of the coil receiving part 51 to place the four coil parts 15 in the receiving part 51, and then the other coil end 52 is fixed to the bottom wall 51a with the other protruding part 16-1 of the four coil parts 15 inserted into the through holes 52a.

The coil end 52 also has five slits 52b formed on both sides parallel to the axial direction of the four sets of coil parts 15 arranged in the receiving section 51 for installing a magnetic shielding plate 70 (FIG. 9(c)) described later. In other words, the slits 52b are formed on both sides of the through hole 52a in the depth direction from the opening side of the receiving space. Note that at least one of the pair of coil ends 52 needs to be removable from the bottom wall 51a.

9(b), referring to FIG. 9(c), magnetic shielding plates 70 longer than the coils 15 are arranged on both sides of the axial direction of the four sets of coils 15 arranged in a row. That is, a total of five magnetic shielding plates 70 are attached to the slits 52b of a pair of coil ends 52, one for each. The magnetic shielding plates 70 are intended to prevent adjacent linear shaft motors from interfering with each other (e.g., cogging) due to the adjacent coils 15 and the permanent magnets 12 in the motor shaft 11. For this reason, the magnetic shielding plates 70 are made of a high magnetic permeability material, for example, SPCC (cold-rolled steel plate), and have a length that spans at least the movable range of the multiple permanent magnets 12 in the motor shaft 11. In addition, the width of the magnetic shielding plates 70 is greater than the depth of the receiving space of the receiving portion 51, and the width of the portion corresponding to at least a part of the receiving space area is approximately the same as the depth of the receiving space. This is to allow the circuit board 80 to be attached to the portion corresponding to the receiving space area, as described later with reference to FIG. 13.

Next, referring to FIG. 9(d), a curable resin (adhesive) 75 is poured between the coil portion 15 and the magnetic shielding plate 70 in the receiving portion 51 and allowed to harden.

The magnetic shielding plates 70 only need to be provided at locations corresponding to the spaces between at least adjacent coil sections 15, and the two outermost plates may be omitted. The coil sections 15 and the magnetic shielding plates 70 may be fixed together by a method other than adhesion using a curable resin 75.

12 shows an example of a circuit board 80 installed on the opening side of the receiving space in the coil unit made by the manufacturing method of FIG. 9, and FIG. 13 shows an example of a coil unit in which the circuit board 80 is installed by screwing. The circuit board 80 has a notch 81 for exposing a part of the four coil parts 15, and five slits 82 for allowing the wide part of the magnetic shielding plate 70 to protrude from the circuit board 80. The notch 81 is formed to facilitate electrical connection (not shown) between the conductive pattern 84 for coil connection formed on its periphery and the four coil parts 15. On the other hand, the slit 82 is formed at a position on the upper side of the circuit board 80, so that even if the magnetic shielding plate 70 peels off from the receiving part 51 due to poor adhesion during operation, the lower end of the wide part is caught on the lower edge of the slit 82, preventing the magnetic shielding plate 70 from falling.

Although not shown in FIG. 13, the circuit board 80 installed on the opening side of the receiving space in the coil unit is covered with a lid member 55 fixed to the coil fixing member 50 by screws, as shown in FIG. 8. Of course, five grooves 55a are formed on the upper end side of the lid member 55 to receive the protruding portion of the magnetic shielding plate 70 protruding from the circuit board 80.

12 and 13, 83 is a pair of magnetic sensors, such as analog Hall sensors (hereinafter abbreviated as Hall sensors), for detecting the position of the permanent magnet 12 in the motor shaft 11, and is used for position control of the motor shaft 11 in the linear shaft motor 10. The pair of Hall sensors 83 are installed at a position corresponding to the motor shaft 11 and adjacent to the wide portion of the magnetic shielding plate 70, with a predetermined installation interval in the moving direction of the motor shaft 11. The installation interval of the pair of Hall sensors 83 is set to an electrical angle of 90 degrees of the waveform of the surface magnetic flux density of the motor shaft 11 (permanent magnet 12) as shown in FIG. 14. This is based on the fact that the inventors measured the external magnetic field in the radial direction of the linear shaft motor 10 and found that the surface magnetic flux density of the motor shaft 11 (permanent magnet 12) becomes a waveform close to a sine wave when it moves away from the surface of the motor shaft 11 to a certain extent, as shown in FIG. 15. In this embodiment, the measurement data shown in FIG. 15 is referenced to determine the location of the Hall sensor 83 where data closest to a sine wave is obtained.

In this embodiment, the pair of Hall sensors 83 are installed between the wide parts of the two magnetic shielding plates 70 on the front side of the circuit board 80 (the side opposite to the receiving portion 51) for the following reasons. In other words, the wide part of the magnetic shielding plate 70 is extended into the receiving portion 51 of the coil fixing member 50 by forming a slit 82 in the circuit board 80. This is to prevent the pair of Hall sensors 83 installed between the wide parts of the two magnetic shielding plates 70 from being affected by the magnetic field from the adjacent linear shaft motor 10. The electric circuit mounted on the circuit board 80 is mainly connected to the multiple coils 14 to drive and control the four linear shaft motors 10, but the circuit will not be described and the position control system of the linear shaft motor 10 will be described with reference to FIG. 16.

Figure 16 is a block diagram of a position control system that controls the linear shaft motors 10 individually, and this position control system is installed on the linear shaft motors 10 of each axis. However, the microcomputer 88 can be common to the linear shaft motors 10 of all axes. This position control system includes two hall sensors 83 installed on a circuit board 80, an operational amplifier 85 that processes detection signals from the two hall sensors 83, an interpolator 86 that digitizes signals from the operational amplifier 85, a motor drive circuit 87 that drives and controls the motor shaft 11 of the linear shaft motor 10 based on the digital signal from the interpolator 86, and a microcomputer 88 that outputs operation commands such as the amount of movement, movement speed, and direction signals required to drive the linear shaft motor 10 to the motor drive circuit 87.

This position control system has two control forms: one where a negative voltage signal is generated in addition to a positive voltage signal from the detection signals of the two Hall sensors 83 (with signal inversion), and one where only a positive voltage signal is generated from the detection signals of the two Hall sensors 83 (without signal inversion). Figure 16 shows the case without signal inversion, but with signal inversion, the number of output signal lines after the operational amplifier 85 will be different.

(Without signal inversion)
1. The surface magnetic flux density of the motor shaft 11 is detected by the Hall sensor 83 and output as an analog voltage signal. The surface magnetic flux density of the motor shaft 11 is a sine wave along the axial direction, and when two Hall sensors 83 are arranged at 1/4 of the magnetic pole pitch (hereinafter referred to as the magnet pitch) of the permanent magnet 12 and detection is performed, two sine wave voltage signals with a phase difference of 90 electrical degrees, that is, a sine wave (hereinafter referred to as a Sin wave) voltage signal and a cosine wave (hereinafter referred to as a Cos wave) voltage signal can be generated.

2. The analog voltage signals output from the two Hall sensors 83 are input to the operational amplifier 85. The operational amplifier 85 adjusts the output voltages of the two Hall sensors 83 to match the driver input.

3. The driver's interpolator 86 digitizes the two analog signals input from the operational amplifier 85 and divides them by a specified number of bits. This number of divisions defines the resolution (magnet pitch / number of divisions); for example, when the magnet pitch is 24 mm and the number of divisions is ²¹⁴ , the resolution is 1.5 μm. As a result, the two analog voltage signals (sine wave voltage signal, cosine wave voltage signal) become two square wave signals (position signals) that are out of phase with each other by 90 electrical degrees.

4. The motor drive circuit 87 detects the current position and speed of the motor shaft 11 (dispensing head 40) using the two square wave signals input from the interpolator 86, and issues a position control command to the linear shaft motor 10 (coil section 15).

(When signal inversion occurs)
1. The surface magnetic flux density of the motor shaft 11 is detected by two Hall sensors 83 and output as an analog voltage signal. The surface magnetic flux density of the motor shaft 11 is a sine wave along the axial direction, and when two Hall sensors 83 are arranged at 1/4 of the magnetic pole pitch (hereinafter referred to as magnet pitch) of the permanent magnet 12 and detection is performed, two analog sine wave voltage signals with a phase difference of 90 electrical degrees, that is, a sine wave voltage signal and a cosine wave voltage signal, can be generated.

2. The two analog voltage signals output from the two Hall sensors 83 are input to the operational amplifier 85. The operational amplifier 85 generates an inverted signal for each of the two input analog voltage signals (sine wave voltage signal, cosine wave voltage signal). As a result, in addition to the sine wave voltage signal and cosine wave voltage signal input from the Hall sensor 83, a -sine wave voltage signal and a -cosine wave voltage signal are generated, resulting in four analog signals. The operational amplifier 85 also adjusts the output voltage of the Hall sensor 83 to match the driver input. As described above as another form of control, only the sine wave voltage signal and the cosine wave voltage signal are sufficient, but generating a -sine wave voltage signal and a -cosine wave voltage signal makes it more resistant to noise.

3. The driver's interpolator 86 digitizes the four analog signals input from the operational amplifier 85 and divides them by the specified number of bits. The resolution, which is expressed by the magnet pitch and the number of divisions, is as described above. As a result, the four analog voltage signals become four square wave signals (position signals).

4. The motor drive circuit 87 detects the current position and speed of the motor shaft 11 (dispensing head 40) based on the four rectangular wave signals (position signals) input from the interpolator 86, and issues a position control command to the linear shaft motor 10 (coil section 15).

Next, with reference to Figures 17 to 23 in addition to Figure 8, we will explain the support structure for the eight dispensing heads 40 and the installation form of the guide unit in the eight-axis dispensing device, which can be said to be the main characteristic part of this embodiment.

In Figure 8, the eight-axis dispensing device has first and second motor units 50A, 50B each having eight linear shaft motors 10 arranged in a row in plan view, and housed in first and second coil fixing members (motor housing members) 50, respectively , with four linear shaft motors 10 arranged in a row in plan view, and first and second dispensing head support members (driven body support members) 60A, 60B which have four sets of guide portions 44 and support the four dispensing heads 40 movably in the central axial direction while arranged in a row in plan view, and which are attached to the first and second motor units 50A, 50B, respectively .

The extension length (length in the arrangement direction of the dispensing head) of the first and second dispensing head support members (driven body support members) 60A, 60B is slightly longer than the extension length (length in the arrangement direction of the linear shaft motors) of the first and second motor units 50A, 50B, the reason for which will be described later.

The eight-axis dispensing device also has first and second motor units 50A, 50B facing each other with first and second dispensing head support members 60A, 60B sandwiched between them , and the arrangement of the four linear shaft motors 10 in the first motor unit 50A and the arrangement of the four linear shaft motors 10 in the second motor unit 50B are combined in a staggered manner in plan view, so that the guide portions 44 of the first dispensing head support member and the guide portions 44 of the second dispensing head support member 60B are adjacent to each other in plan view and are alternately arranged vertically next to each other.

Figure 17 is a top view showing the arrangement of the upper connecting member 32 in the 8-axis dispensing device shown in Figure 1, and shows that the arrangement (pitch P1) of the four linear shaft motors 10 in the first motor unit 50A and the arrangement (pitch P1) of the four linear shaft motors 10 in the second motor unit 50B are staggered in plan view.

On the other hand, FIG. 18 is a plan view of the 8-axis dispensing device shown in FIG. 1, seen from above, omitting the upper connecting member 32, the linear shaft motor 10, and the dispensing head 40, and shows the first dispensing head support member 60A attached to the first motor unit 50A and the second dispensing head support member 60B attached to the second motor unit 50B in a separated state.

Figure 18 shows the following: The arrangement (pitch P1) of the four linear shaft motors 10 of the first motor unit 50A and the arrangement (pitch P1) of the four linear shaft motors 10 of the second motor unit 50B are combined to form a staggered pattern in a plan view. Figure 18 also shows the following:

That is, in the first dispensing head support member 60A attached to the first motor unit 50A, the four sets of guide parts 44 are arranged so as to be shifted in the arrangement direction by a pitch of P1/2 relative to the arrangement of the four linear shaft motors 10. The same is true for the second dispensing head support member 60B, which is also arranged so as to be shifted in the arrangement direction by a pitch of P1/2 relative to the arrangement of the four sets of guide parts 44 in the first dispensing head support member 60A.

On the other hand, Fig. 19 is a plan view showing the first dispensing head support member 60A and the second dispensing head support member 60B shown in Fig. 18 in a coupled state. Figs. 18 and 19 show the following. That is, when the separated state shown in Fig. 18 is changed to the coupled state shown in Fig. 19, the four sets of guide parts 44 (pitch P1) of the first dispensing head support member 60A and the four sets of guide parts 44 (pitch P1) of the second dispensing head support member 60B are adjacent to each other in a plan view and are alternately arranged vertically next to each other, and the dispensing head 40 supported by the four sets of guide parts 44 of the first dispensing head support member and the dispensing head 40 supported by the four sets of guide parts 44 of the second dispensing head support member 60B are adjacent to each other in a plan view and are alternately arranged next to each other (pitch P2 = P1/2).

19 also shows the following. That is, the four sets of guide parts 44 installed on the first dispensing head support member 60A combined with the first motor unit 50A are the guide parts 44 of the four dispensing heads 40 connected to the respective motor shafts 11 of the four linear shaft motors 10 in the second motor unit 50B, and the four sets of guide parts 44 installed on the second dispensing head support member 60B combined with the second motor unit 50B are the guide parts 44 of the four dispensing heads 40 connected to the respective motor shafts 11 of the four linear shaft motors 10 in the first motor unit 50A. For example, referring to Figures 17, 18, and 19, the dispensing head 40 on the far left side in the figures is supported by a guide portion 44 mounted on the first dispensing head support member 60A, and this dispensing head 40 is connected to the motor shaft of the linear shaft motor 10 on the far left side in the figures by the upper connecting member 32 on the far left side in the figures, and this linear shaft motor 10 is mounted on the second motor unit 50B.

Figure 20 shows the first dispensing head support member 60A, with (a) being a top view and (b) being a front view. Figure 21 shows the second dispensing head support member 60B, with (a) being a top view and (b) being a front view.

8, 20, and 21, the first dispensing head support member 60A has two mounting parts (first mounting parts) 61 attached to the surface of the first motor unit 50A facing the second motor unit 50B, and an upper bridge 62-1 and a lower bridge 62-2 as first bridge parts that are stretched between these two mounting parts 61 to install four sets of guide parts 44. The upper bridge 62-1 and the lower bridge 62-2 each have four upper protrusions 62-11 (pitch P1) and lower protrusions 62-21 (pitch P1) that protrude toward the second motor unit 50B and have holes for passing the head body 41 of the dispensing head 40 through. The four lower protrusions 62-21 provided on the lower bridge 62-2 are located in positions that overlap the four upper protrusions 62-11 provided on the upper bridge 62-1 in a plan view.

Similar to the first dispensing head support member 60A, the second dispensing head support member 60B also has two mounting parts (second mounting parts) 61 that are attached to the surface of the second motor unit 50B facing the first motor unit 50A, and an upper bridge 62-1 and a lower bridge 62-2 that serve as second bridge parts that are hung between these two mounting parts 61 to install four sets of guide parts 44. The upper bridge 62-1 and the lower bridge 62-2 each have four upper protrusions 62-11 (pitch P1) and lower protrusions 62-21 (not shown) that protrude toward the first motor unit 50A and have holes for passing the head body 41 of the dispensing head 40 through. However, the protrusions formed on the upper bridge 62-1 and lower bridge 62-2 of the second dispensing head support member 60B are offset by a pitch P2 (=P1/2) in a plan view from the protrusions formed on the upper bridge 62-1 and lower bridge 62-2 of the first dispensing head support member 60A.

The four upper guides 44-1 of the first dispensing head support member 60A are each installed (pitch P1) on the upper protrusion 62-11 with the insertion hole 44-1a, through which the head body 41 is inserted, mating with the hole in the upper protrusion 62-11 of the upper bridge 62-1 and protruding from the upper bridge 62-1. The upper guides 44-1 are installed on the upper protrusion 62-11 by screws 45 in the flanges on both sides of the through hole 44-1a of the spline outer cylinder. The lower guides 44-1 are installed on the lower protrusion 62-21 in a similar manner. Similarly, the four lower guides 44-2 of the first dispensing head support member 60A are installed (pitch P1) on the lower protrusion 62-21 in a state where the insertion holes 44-2a (not shown) through which the head body 41 is inserted are aligned with the holes of the lower protrusion 62-21 of the lower bridge 62-2 and protrude from the lower bridge 62-2. The four upper guides 44-1 installed on the upper bridge 62-1 of the second dispensing head support member 60B and the lower guides 44-2 installed on the lower bridge 62-2 are the same as those of the first dispensing head support member 60A, except that they are installed so as to be shifted by pitch P2 (=P1/2) in a plan view from the upper guides 44-1 and lower guides 44-2 on the first dispensing head support member 60A side, so a description thereof will be omitted.

As described above, the first dispensing head support member 60A has an upper bridge 62-1 with four upper protrusions 62-11 and a lower bridge 62-21 with four lower protrusions 62-21 that overlap each other in a plan view as a first bridge section for installing the four sets of guide sections 44, and four upper guides 44-1 and four lower guides 44-2 are installed on the four upper protrusions 62-11 and the four lower protrusions 62-21, respectively, as four sets of guide sections 44. This is also the case with the second dispensing head support member 60B.

Referring also to Figures 20 and 21, in this embodiment in particular, the upper bridge 62-1 of the first dispensing head support member 60A is at a higher height than the upper bridge 62-1 of the second dispensing head support member 60B, and the lower bridge 62-2 of the first dispensing head support member 60A is also at a higher height than the lower bridge 62-2 of the second dispensing head support member 60B. Of course, the upper bridge 62-1 and lower bridge 62-2 of the first dispensing head support member 60A may be at a lower height than the upper bridge 62-1 and lower bridge 62-2 of the second dispensing head support member 60B, respectively.

Furthermore, in this embodiment, the upper guide 44-1 of the first dispensing head support member 60A is installed on the upper surface side of the upper bridge 62-1 (upper protrusion 62-11), and the lower guide 44-2 is installed on the lower surface side of the lower bridge 62-2 (lower protrusion 62-21) (Fig. 20(b)). Similarly, the upper guide 44-1 of the second dispensing head support member 60B is installed on the upper surface side of the upper bridge 62-1 (upper protrusion 62-11), and the lower guide 44-2 is installed on the lower surface side of the lower bridge 62-2 (lower protrusion 62-21) (Fig. 21(b)).

Due to the support structure of the eight dispensing heads 40 and the installation form of the guide section 44 described above, as shown in Figures 18 and 19, the through holes 44-1a of the upper guide 44-1 of the first dispensing head support member 60A and the through holes 44-1a of the upper guide 44-1 of the second dispensing head support member 60B are arranged alternately adjacent to each other in a line at a pitch P2 (=P1/2) in a plan view, even though they are at different height positions. Similarly, the through holes 44-2a (not shown) of the lower guide 44-2 of the first dispensing head support member 60A and the through holes 44-2a (not shown) of the lower guide 44-2 of the second dispensing head support member 60B are arranged alternately adjacent to each other in a line at a pitch P2 in a plan view, even though they are at different height positions.

Figure 22 is a perspective view showing a state where a first dispensing head support member 60A supporting four head bodies 41 and a second dispensing head support member 60B supporting four head bodies 41 are butted together and fixed. The first dispensing head support member 60A and the second dispensing head support member 60B are fixed by screwing in a screw 63 while butting the first mounting portion 61 on both sides of the first dispensing head support member 60A and the second mounting portion 61 on both sides of the second dispensing head support member 60B. This is the reason why the extension length of the first and second dispensing head support members 60A and 60B is made slightly longer than the extension length of the first and second motor units 50A and 50B. In other words, as shown in Figure 1, the first and second mounting portions 61 protruding from both ends of the first and second motor units 50A and 50B can be used to tighten and fix the first and second motor units 50A and 50B with the screw 63.

Figure 23 is a front view of Figure 22. As is clear from Figure 23, the four upper guides 44-1 and lower guides 44-2 in the first dispensing head support member 60A and the four upper guides 44-1 and lower guides 44-2 in the second dispensing head support member 60B are installed alternately in a vertically staggered manner, which provides the following effects. When supporting eight adjacent dispensing heads with guide portions of ball splines (or ball bushes), if the guide portions are installed at the same height, the intervals between the dispensing heads must be large to prevent interference between the ball splines, which is a problem that hinders the compactification of the entire device. In contrast, by installing the guide portions of the eight dispensing heads in a vertically staggered manner as shown in Figure 23, the above-mentioned problems do not occur.

Figure 24 is a plan view showing another example of the connection form of the first dispensing head support member 60A and the second dispensing head support member 60B. In Figure 22, the first dispensing head support member 60A and the second dispensing head support member 60B are directly connected with screws 63, but in this example, the first dispensing head support member 60A and the second dispensing head support member 60B are integrated by a connecting plate 65 with a distance d1 between them. The connecting plate 65 is screwed to the first attachment 61 of the first dispensing head support member 60A and the second attachment 61 of the second dispensing head support member 60B.

Figure 25 is a plan view showing yet another example of the connection form of the first dispensing head support member 60A and the second dispensing head support member 60B. In this example, the first dispensing head support member 60A and the second dispensing head support member 60B are integrated by a connecting plate 65' with the first and second motor units 50A and 50B spaced apart by a distance d1. The connecting plate 65' is screwed to the end faces of the first motor unit 50A and the second motor unit 50B.

Figure 26 shows a second embodiment of the present invention, and is a plan view of the 8-axis dispensing device shown in Figure 1 from above, with the upper connecting member 32, linear shaft motor 10, and dispensing head 40 omitted, showing the first dispensing head support member 60A attached to the first motor unit 50A and the second dispensing head support member 60B attached to the second motor unit 50B in a separated state. The arrangement of the four linear shaft motors 10 in the second motor unit 50B and the arrangement of the four linear shaft motors 10 in the first motor unit 50A are staggered, the same as in the first embodiment.

The second embodiment differs from the first embodiment in the following respects. In the first embodiment, referring to FIG. 18, in the first dispensing head support member 60A attached to the first motor unit 50A, the four sets of guide parts 44 are installed so as to be shifted in the arrangement direction by P1/2 pitch with respect to the arrangement of the four linear shaft motors 10. In contrast, in the second embodiment, referring to FIG. 26, in the first dispensing head support member 60A' attached to the first motor unit 50A, the four sets of guide parts 44' are installed so as to be parallel to the arrangement of the four linear shaft motors 10. In other words, the four sets of guide parts 44' are installed so that the centers of the four sets of guide parts 44' are located at positions extending from the centers of the four linear shaft motors 11 in a direction perpendicular to the arrangement direction. The second dispensing head support member 60B' is similar, but is installed so that it is shifted in the arrangement direction by a pitch of P2 (=P1/2) from the arrangement of the four sets of guide parts 44' on the first dispensing head support member 60A'.

In the second embodiment, too, the arrangement (pitch P1) of the four linear shaft motors 10 of the first motor unit 50A and the arrangement (pitch P1) of the four linear shaft motors 10 of the second motor unit 50B are combined so as to form a staggered pattern in a planar view, and the four sets of guide portions 44' of the first dispensing head support member 60A' and the four sets of guide portions 44' of the second dispensing head support member 60B' are adjacent to each other in a planar view, and are alternately arranged vertically and horizontally (pitch P2 = P1/2).

However, in the second embodiment, the four sets of guide parts 44' installed on the first dispensing head support member 60A' combined with the first motor unit 50A are used as guide parts 44' of the four dispensing heads 40 connected to the respective motor shafts 11 of the four linear shaft motors 10 in the first motor unit 50A'. On the other hand, the four sets of guide parts 44' installed on the second dispensing head support member 60B' combined with the second motor unit 50B are used as guide parts 44' of the four dispensing heads 40 connected to the respective motor shafts 11 of the four linear shaft motors 10 in the second motor unit 50B'. For example, the dispensing head on the left side of the figure is supported by a guide portion 44' mounted on the first dispensing head support member 60A', and this dispensing head is connected to the motor shaft of the linear shaft motor on the left side of the figure by the upper connecting member on the left side of the figure, and this linear shaft motor 10 is mounted on the first motor unit 50A.

The installation structure of the upper guide and lower guide on the upper bridge and lower bridge in the first dispensing head support member 60A' and the second dispensing head support member 60B' is the same as in the first embodiment, so illustrations and explanations are omitted.

Next, referring to Figures 27 and 28, a position detection means required for position control for dispensing and aspirating liquid by the dispensing head 40 by detecting the upward movement position (upper limit position) of the upper connecting member 32 will be described. Figure 27 is a perspective view for explaining a detector 100 that detects the upward movement position of the upper connecting member 32 in the 8-axis dispensing device shown in Figure 1. Also, Figure 28 is a diagram for explaining an example of the installation form of the detector 100 shown in Figure 27, where (a) is a side view of the 8-axis dispensing device and (b) is a perspective view of the 8-axis dispensing device.

In this example, the upward movement position of the dispensing head 40 of the same set is detected by detecting the upward movement position of the upper connecting member 32 as the upper limit position, separately from the position control of the linear shaft motor 10 by the position detection signal from the pair of Hall sensors 83. For this purpose, as shown in FIG. 27, a hollow shaft-shaped detectable protrusion 101 is provided on the upper end surface near the center of each upper connecting member 32, and a photosensor 102 is provided as a limit sensor so that light is blocked when the detectable protrusion 101 moves upward to a predetermined position. As shown in FIG. 28(a) and (b), the photosensor 102 is fixedly arranged on a sensor installation board 111 via a support plate 110 fixed to the first and second dispensing head support members 60A and 60B at a position higher than the upward movement position of the upper connecting member 32, and eight photosensors 102 are installed on the sensor installation board 111 so as to correspond to the eight detectable protrusions 101 of the eight-axis dispensing device. In an eight-axis dispensing device, when the linear shaft motor 10, dispensing head 40, lower connecting member 31, and upper connecting member 32 are movable parts, the sensor installation board 111 (photosensor 102) becomes a fixed part together with the pair of coil fixing members 50 and the first and second dispensing head support members 60A and 60B.

The detector 100 is used not only as a means for detecting the upward movement position of the dispensing head 40 associated with the dispensing operation of aspirating and dispensing liquid, but also as a means for determining the origin position when starting the dispensing operation. The origin positioning is as follows.

When the dispensing operation starts, the detectable protrusion 101 blocks the light path of the photosensor 102, and each dispensing head 40 moves upward until a detection signal is output from the photosensor 102. This operation performs an offset operation based on the detection signal output from the photosensor 102. Since the offset positions are at the same height for each axis, this position is used as the reference point for positioning control of the linear shaft motor 10, which will be described later.

In addition, in Figures 27 and 28, a cable 103 for signal transmission extends from one end of the photosensor 102, but for convenience, it is shown cut away with only a portion remaining.

[Effects of the embodiment]
(1) The eight-axis dispensing device according to the first and second embodiments described above can be configured to be compact as a whole while ensuring the necessary pitch between adjacent linear shaft motors. One reason for this is as follows. When eight adjacently arranged dispensing heads are supported by guides, if the guides such as ball splines are installed at the same height, the intervals between the dispensing heads must be large to prevent interference between the guides, which is a problem that hinders the compactification of the entire device. In contrast, by setting the guides of the eight dispensing heads to be installed alternately up and down as shown in Figure 23, the above-mentioned problem does not occur.

(2) As described above, the eight-axis dispensing device according to the first and second embodiments does not require the pitch (spacing) P1 of the linear shaft motor 10 to be small, even though it has eight axes, so the dispensing device can be constructed without reducing the size of the permanent magnet 12 and the coil 14. This is effective from the following perspectives.

For multi-axis dispensing devices, it is required to reduce the pitch (spacing) between the dispensing heads. This is because by reducing the pitch between the dispensing heads, the entire multi-axis dispensing device can be made compact and the movable range can be increased. However, in the case of a multi-axis dispensing device with a row of dispensing heads, the diameter of the linear shaft motor must be reduced in order to reduce the pitch between the dispensing heads. To achieve this, the diameter of the permanent magnet must be reduced or the diameter of the coil, i.e., the number of turns of the coil, must be reduced. This means that the thrust of each axis is reduced. However, a certain thrust is required for the up and down movement of the dispensing head. This is because, for example, referring to FIG. 7, the removal of the tip 42 attached to the tip of the nozzle 43 is automated by moving the head body 41 upward while the narrowed portion between the tip 42 and the nozzle 43 is clamped by a jig (not shown) at a location other than the location where the liquid is suctioned and discharged. In other words, if the thrust of the dispensing head's up and down movement becomes weaker, automatic removal of the tip 42 becomes difficult.

In response to the above-mentioned circumstances, the eight-axis independently controlled dispensing device according to this embodiment can reduce the pitch between the dispensing heads and obtain a predetermined thrust force during the up and down movement of the dispensing heads without reducing the diameter of the linear shaft motor, thereby eliminating the above-mentioned problems.

(3) Typically, the coil sections of a linear shaft motor are housed in a casing for each coil section. In contrast, in the first and second embodiments described above, multiple motor shafts 11 are arranged adjacent to each other, and multiple sets of coil sections 15 are grouped together into a unit, which reduces the number of parts in the coil unit, reduces assembly labor, and saves space.

(4) In addition, magnetic shielding plates 70 are installed on both axial sides of each coil section 15, and the coil sections 15 and the magnetic shielding plates 70 can be fixed simultaneously using a hardening resin 75. This also makes it possible to reduce the number of parts in the coil unit, reduce assembly labor, and save space.

The above describes a preferred embodiment of the present invention when applied to an eight-axis dispensing device, but it goes without saying that the present invention is not limited to the above embodiment. In other words, the present invention can be applied to any multi-axis dispensing device with two or more axes, either an independent control type that controls each axis individually, or a simultaneous control type that controls multiple axes collectively to perform the same operation, and furthermore, it is not limited to dispensing devices, but can be applied to multi-axis linear motor actuators in general.

10: Linear shaft motor, 11: Motor shaft, 12: Permanent magnet, 13: Cylinder, 14: Coil, 16: Coil integrated cylinder, 31: Lower connecting member, 32: Upper connecting member, 40: Dispensing head, 41: Head body, 42: Tip, 43: Nozzle, 44: Guide portion, 44-1: Upper guide, 44-2: Lower guide, 50: Coil fixing member, 50A: First motor unit, 50B: Second motor unit, 51: Receiving portion, 52: Coil end, 6 0A: First dispensing head support member, 60B: Second dispensing head support member, 61: First and second mounting parts, 62-1: Upper bridge, 62-11: Upper protrusion, 62-2: Lower bridge, 62-21: Lower protrusion, 65, 65': Connecting plate, 70: Magnetic shielding plate, 80: Circuit board, 83: Hall sensor, 100: Detector, 102: Photosensor, 111: Sensor installation board

Claims (7)

A multi-axis linear motor actuator includes n combinations (n is a positive even number) of a linear shaft motor having a motor shaft driven in a central axis direction, and an axially shaped driven body extending parallel to the linear shaft motor and connected to at least one end of the motor shaft by a first connecting member so as to be displaced integrally with the motor shaft,
a first motor unit and a second motor unit, each of which includes a first motor housing member and a second motor housing member, the first motor housing member and the second motor housing member housing the first motor unit and the second motor unit, the first motor unit and the second motor unit housing the second motor unit, the first motor unit and the second motor unit housing the second motor unit,
a first and a second driven body support member having n/2 sets of guide portions and supporting the driven body in a state where the driven body is aligned in a line in a plan view so as to be movable in a central axial direction, the first and second driven body support members being attached to the first and second motor units, respectively ;
A multi-axis linear motor actuator characterized in that the first and second motor units are opposed to each other with the first and second driven body support members sandwiched between them , and the arrangement of the n/2 linear shaft motors in the first motor unit and the arrangement of the n/2 linear shaft motors in the second motor unit are combined so as to be staggered in a planar view, so that the guide portions of the first driven body support member and the guide portions of the second driven body support member are adjacent to each other in a planar view and are alternately arranged above and below . the n/2 sets of guide parts provided on the second driven body support member combined with the second motor unit are guide parts for n/2 driven bodies connected to respective motor shafts of the n/2 linear shaft motors in the first motor unit;
The multi-axis linear motor actuator according to claim 1, characterized in that the n/2 sets of guide portions installed on the first driven body support member combined with the first motor unit are guide portions for n/2 driven bodies connected to respective motor shafts of the n/2 linear shaft motors in the second motor unit. the n/2 sets of guide parts provided on the first driven body support member combined with the first motor unit are guide parts for n/2 driven bodies connected to respective motor shafts of the n/2 linear shaft motors in the first motor unit;
The multi-axis linear motor actuator according to claim 1, characterized in that the n/2 sets of guide portions installed on the second driven body support member combined with the second motor unit are guide portions for n/2 driven bodies connected to respective motor shafts of the n/2 linear shaft motors in the second motor unit. the first driven body support member has two first mounting portions attached to a surface of the first motor unit facing the second motor unit, and a first bridge portion spanning between the two first mounting portions for installing the n/2 guide portions, the first bridge portion having n/2 sets of protruding portions protruding toward the second motor unit and having holes for passing the driven bodies therethrough;
the second driven body support member has two second mounting portions attached to a surface of the second motor unit facing the first motor unit, and a second bridge portion spanning between the two second mounting portions for installing the n/2 guide portions, the second bridge portion having n/2 sets of protruding portions protruding toward the first motor unit and having holes for passing the driven bodies therethrough;
A multi-axis linear motor actuator as described in any one of claims 1 to 3, characterized in that the guide portions of the first and second driven body support members are respectively installed on the protruding portions with insertion holes through which the driven body is inserted mating with holes in the protruding portions and protruding from the first and second bridge portions, so that the insertion holes of the guide portion of the first driven body support member and the insertion holes of the guide portion of the second driven body support member are adjacent to each other in a row and alternately in a planar view. the first driven body support member has, as the first bridge portion, an upper bridge having n/2 upper protrusions and a lower bridge having n/2 lower protrusions, which are positioned so as to overlap each other in a plan view, and n/2 upper guides and n/2 lower guides are provided on the n/2 upper protrusions and the n/2 lower protrusions, respectively, as the n/2 sets of guide portions;
The second driven body support member also has an upper bridge having n/2 upper protrusions and a lower bridge having n/2 lower protrusions as the second bridge portion, which are positioned so as to overlap each other in a plan view, and n/2 upper guides and n/2 lower guides are installed on the n/2 upper protrusions and the n/2 lower protrusions, respectively, as the n/2 sets of guide portions,
A multi-axis linear motor actuator as described in any one of claims 1 to 4, characterized in that the upper bridge of the first driven body support member is at a higher or lower height position than the upper bridge of the second driven body support member, and the lower bridge of the first driven body support member is also at a higher or lower height position than the lower bridge of the second driven body support member. an upper guide of the first driven body support member is installed on an upper surface side of the upper bridge, and a lower guide of the first driven body support member is installed on a lower surface side of the lower bridge,
A multi-axis linear motor actuator as described in any one of claims 1 to 5, characterized in that the upper guide of the second driven body support member is installed on the upper surface side of the upper bridge, and the lower guide is installed on the lower surface side of the lower bridge. The multi-axis linear motor actuator according to any one of claims 4 to 6, characterized in that the length of the guide parts in the first driven body support member and the second driven body support member in the arrangement direction is made larger than the length of the linear shaft motors in the first motor unit and the second motor unit in the arrangement direction, the two first mounting parts of the first driven body support member and the two second mounting parts of the second driven body support member are protruded from both ends of the first motor unit and the second motor unit in the arrangement direction, and the first driven body support member and the second driven body support member are fixed at the protruding parts.