JPH0297266A - Double-sided linear motor - Google Patents

Abstract

PURPOSE:To cool a primary side stator and a secondary conductor efficiently by sending a cooling air from the outside of coil ends on both sides through a ventilating gap to the traveling gap side by cooling fans provided in the manner of facing each other with the coil ends on both sides between. CONSTITUTION:Blade pieces 28a of respective cooling fans 28 are arranged to face each other with coil ends 25 on both sides in between. By rotation of the cooling fans 28, the outside air is absorbed into a fan cover 32 as shown by the arrow A and sent almost horizontally toward the coil end 25 as shown by the arrow B. A part of the cooling air hits the coil end 25 and flows along the coil end 25 as shown by the arrow C, but the cooling air mostly passes through the ventilating gap between respective coil ends 25 and flows to the traveling gap 22 side. Then, two flows of the cooling air hit each other from both sides of a secondary conductor 23 and the cooling air flows along both faces of the secondary conductor 23 and into the traveling gap 22.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a double-sided linear motor with an improved cooling system.

(Prior Art) Conventionally, double-sided linear motors have been developed, for example, in Japanese Patent Application Laid-Open No. 1986-61. −
As shown in Japanese Patent No. 173606, it is used as a drive source for a conveyance system. As shown in FIG. 9, in this conveyance system, double-sided linear motors 2 are arranged at predetermined intervals along a rail 1, and the conveyance table 3 is moved to a station 4 by the double-sided linear motors 2 to transfer the load. It is used for loading and unloading. In this case, the double-sided linear motor 2 has a coil 5 as shown in FIGS. 10 and 11.
A pair of stator cores 6 equipped with the stator cores 6 are arranged to face each other within the rail 1 to form a primary stator 7, and a running gap 8 is formed between the stator cores 6 on both sides. A plate-shaped secondary conductor 9 is configured to run within this running gap 8.

This secondary conductor 9 is attached to the lower surface of the transport table 3 in a hanging manner, and the transport table 3 is movable on the rail 1 via wheels ]0.

The driving principle of the double-sided linear motor 2 with such a configuration is as follows.
By energizing and exciting the coil 5 of the primary side stator 7, a moving magnetic field is generated in the running gap 8, and this moving magnetic field gives thrust (kinetic energy) to the secondary conductor 9 to drive the transport table 3. It is something to do.

(Problems to be Solved by the Invention) By the way, in the conventional configuration described above, the primary stator 7 and the secondary conductor 9, which generate heat during operation of the double-sided linear motor 2, are cooled by natural heat radiation. , the cooling performance is low, and therefore, if the coil 5 is continuously energized, it may generate excessive heat and cause the coil 5 to burn out.
The coil 5 is energized intermittently as shown in FIG. In this case, if the duty ratio t/T (T is period) is reduced by shortening the energization time t, the temperature rise of the secondary conductor 9 can be suppressed (see Fig. 13), and the starting thrust can be increased (see Fig. 13). 14), as the duty ratio t/T decreases, the distance between each conveyor table 3 (the distance between the previous secondary conductor and the subsequent secondary conductor after passing through the running gap 8) decreases. The disadvantages are that it requires a long time (time to pass) and that the transport efficiency is low. Therefore, in order to increase the conveyance efficiency, it is necessary to increase the duty ratio t/T by lengthening the energizing time t, but as the duty ratio t/T increases, the temperature of the secondary conductor 9 does not rise rapidly. (see Figure 13), the secondary conductor 9 may be deformed due to thermal strain, causing the secondary conductor 9 to come into contact with the stator core 6, or the resistance may change due to a rise in the temperature of the secondary conductor 9. As a result, the flow of magnetic flux into the secondary conductor 9 deteriorates, and the starting thrust becomes small as shown in FIG.

Therefore, in the conventional system, the usable duty ratio t/
The range of T is suppressed to a small value, and as a result, the application range of the double-sided linear motor 2 is limited to short-time rated systems such as the above-mentioned conveyance system, and the secondary conductor 9 is continuously passed through. Not applicable to the system
The drawback was that the range of application as a linear motor was narrow.

In order to improve these drawbacks, in recent years, a double-sided linear motor 2 has been developed in which the cooling method is changed from natural cooling to forced cooling using a blower.

In this case, a blower is provided separately, and the blower sends cooling air through a ventilation duct to the running gap 8 between both stator cores 6.
It is configured to blow air along the

In such a configuration, air blowing efficiency decreases due to pressure loss due to conduit resistance within the ventilation duct, resulting in poor cooling efficiency. Therefore, to ensure sufficient cooling capacity,
This has the disadvantage that the blower has to be made larger, which, together with the space required for the ventilation duct, makes the entire device larger and the manufacturing cost too high.

The present invention has been made to solve such technical problems, and therefore, its purpose is to efficiently cool the primary stator and secondary conductor, and by improving the cooling performance, to reduce the duty ratio of energization to the coil. To provide a double-sided linear motor that can be made larger and can be continuously energized, greatly expanding the range of application as a linear motor, and further reducing the size and cost of the entire device.

[Structure of the Invention] (Means for Solving the Problems) The double-sided linear motor of the present invention has a primary stator configured by housing each coil in each slot of stator cores on both sides facing each other, In a device in which the secondary conductor runs along the running gap between the stator cores on both sides, a ventilation gap is formed between the coil ends of each coil along the end face of each tooth of the stator core. At the same time, cooling fans are provided so as to sandwich the coil ends on both sides and face each other, and the cooling fans blow cooling air from the outside of the coil ends on both sides through the ventilation gap toward the running gap side. This is what I did.

(Function) During operation, the cooling fan blows cooling air from the outside of the coil ends on both sides toward the running gap between the stator cores through the ventilation gap between the coil ends. At this time,
In the process of the cooling air passing through the ventilation gap, the cooling air comes into contact with the end faces of the coil end and the stator core to cool them. On the other hand, when the secondary conductor enters the running gap, the secondary conductor Cooling air impinges on both sides of the secondary conductor from both sides, and the cooling air flows into and out of the running gap along both sides of the secondary conductor to cool the secondary conductor and the primary stator.

After the secondary conductor leaves the running gap, the cooling air from both sides collides at the open end of the running gap, and due to this collision, the cooling air from both sides changes its flow direction by about 90' and runs. Flows toward the inside of the air gap and the tip of the coil end,
The primary stator is also cooled from the inside.

(Example) Hereinafter, a first example in which the present invention is applied to a conveyance system will be described with reference to FIGS. 1 to 7. First, in FIG. 7 showing a plan view of the entire conveyance system, reference numeral 11 denotes a rail for circulating a plurality of conveyance tables 12, and on this rail 1, double-sided linear motors 13 are arranged at predetermined intervals.

In this case, each transport table 12 is connected in a loop across the entire rail 11 via a connector 14, and each transport table 12 is simultaneously driven by each double-sided linear motor 13 to sequentially move to a station 15 to load the load. Loading and unloading is now possible.

Double-sided linear motor 1 used in such a conveyance system
The specific configuration of 3 will be explained based on FIGS. 1 to 6.

That is, the primary stator 16 includes stator cores 17 on both sides facing each other, and a throat l-18 (see FIGS. coils] 9 housed in the clamps 20 (see figure), and each stator core 17 is
(see the figure) is fixed to the leg portion 21 via. and,
The gap between the stator cores 17 on both sides is used as a running gap 22,
A plate-shaped secondary conductor 23 is configured to run within this running gap 22. This secondary conductor 23 has a width dimension in the running direction that is longer than that of the stator core 17 (see figure m4), and is attached to the lower surface of the conveyance table 12 in a hanging manner, and the conveyance table 12 has wheels 24. It is movable on the rails 11 via (see FIG. 3).

As shown in FIG. 5, the coil 19 is formed so that the portion of each coil end 25 near the slot 8 of the stator core 17 extends straight, thereby creating ventilation between the coil ends 25. A space 26 is formed along the end face of each tooth 27 of the stator core 7. Correspondingly, as shown in FIGS. 3 and 4, both stator cores 1
Two cooling fans 28 are provided on the left and right sides of the cooling fan 7, and the blades 28a of the cooling fans 28 are arranged to face each other with the coil ends 25 on both sides in between. Each cooling fan 28 is attached to a mounting plate 29 fixed to the leg portion 21, and this mounting plate 29 includes:
A discharge port 30 (see FIG. 3) is formed at a position facing each cooling fan 28, and a ventilation window 31 (see FIG. 4) is formed on the side of the cooling fan 28. In addition, an air intake port 33 is formed in the fan cover 32 that covers each cooling fan 28 . Corresponding to this intake port 33, a ventilation window 34 for intake is formed on the side surface of the rail 11, as shown in FIG.
The primary stator 16 is located below the primary stator 16.

Next, the operation of the above configuration will be explained. During operation, the coil [9] is continuously energized to keep the primary stator [6] in an excited state, and a moving magnetic field is constantly generated in the running air gap 22, so that thrust (kinetic energy) is continuously applied to the secondary conductor 22. ), and the entire transport table 12 connected in a loop is run along the rail 1].

When the coil 19 is continuously energized in this way, the amount of heat generated by the primary stator 16 and the secondary conductor 23 increases, so during operation, the cooling fan 28 is rotated to perform forced cooling as follows. That is, due to the rotation of the cooling fan 28, the rail 11
The outside air (chilled air) taken in through the ventilation window 34 on the side is drawn into the fan cover 32 as shown by arrow A in FIG. 1, and is blown approximately horizontally toward the coil end 25 as shown by arrow B. . A part of this cooling air collides with the coil end 25 and flows along the coil end 25 as shown by arrow C, but most of the cooling air passes through the ventilation gap 26 between each coil end 25. The water flows along the end surface of the teeth 27 toward the traveling gap 22 side. When the secondary conductor 23 enters the running gap 22 as shown in FIG. 1, cooling air collides with both sides of the secondary conductor 23 from both sides.
Due to the collision, the cooling air turns the flow direction by approximately 90° toward the E direction, flows along both sides of the secondary conductor 23, and also flows into the running gap 22. In addition, after the secondary conductor 23 leaves the running gap 22, as shown in FIG. arrow, approximately 90° toward the E direction.
Instead, it flows inside the running gap 22 and toward the tip side of the coil end 25. In this way, the cooling air is directed to arrow B,
In the process of flowing in the CD and E directions, the coil end 25. Heat is removed from the stator core 17 and the secondary conductor 23 to cool them, and is finally discharged to the outside through the two-part opening of the rail 11 and the ventilation window 35 on the bottom surface.

According to the first embodiment, during operation, the cooling air flows along both the inner and outer sides of the coil end 25, efficiently cooling the coil end 25 from both the inner and outer sides, and the cooling air flows along the stator core. 17 (teeth 27) and the inner surface of the running gap 22, the stator core 1
7 can be efficiently cooled from both the inside and outside, the temperature rise of the primary stator 16 can be suppressed to a low level, and burnout of the coil 19 due to overheating can be prevented. Furthermore, the cooling air flows along both sides of the secondary conductor 23, efficiently cooling the secondary conductor 23 from both sides,
It is possible to suppress the temperature rise of the secondary conductor 23 to a low level, suppress deformation of the secondary conductor 23 due to thermal strain, and prevent contact between the secondary conductor 23 and the stator core 17. This allows the transfer table 12 to run smoothly. Moreover, as mentioned above, the excellent cooling ability makes it possible to increase the duty ratio (longer energization time) of energization to one coil and to continuously energize the coil, making it possible to It can also be applied to a system in which the linear motor continuously passes through the running gap 22, and the range of application as a linear motor can be expanded.

In this case, the cooling system is such that a ventilation gap 26 is formed between the coil ends 25, and cooling fans 28 are provided so as to sandwich the coil ends 25 on both sides and face each other. coil end 2
Since the configuration is such that air is blown from the outside of the vehicle through the ventilation gap 26 toward the travel gap 22 side, a conventional ventilation duct is not required, and the entire device can be made smaller and cost-effective accordingly. Moreover, the problem of pressure loss due to conduit resistance in the conventional ventilation duct can be solved, and the air blowing efficiency can be improved, and the primary stator 16 can be efficiently cooled from both the inside and outside, improving the cooling efficiency. It is also possible to make the 28 itself smaller (thinner).

In the first embodiment, since the width of the stator core 17 is long, two cooling fans 28 are provided on each side so that the cooling air is evenly distributed over the entire primary stator 6. , when the width of the stator core is relatively short or when the amount of heat generated is relatively small, the second method of the present invention shown in FIG.
As in the embodiment, one cooling fan 28 may be provided in the center on both sides of the primary stator 16, and these re-cooling fans 28 may be opposed to each other with the coil ends 25 on both sides in between. In this case, the mounting plate 2 that supports the cooling fan 28
Air guide walls 36 are provided at both upper and lower ends of the stator core 17 to guide the cooling air in the left and right direction along the stator core 17.
The cooling air is directed to the primary stator 1 by the air guiding action with the I plate 29.
6. I try to spread it evenly throughout the whole area.

In addition, the present invention can be modified in various ways, such as a configuration in which three or more sets of cooling fans (six or more in total) are provided, and the configuration of the conveyance system may be changed.

[Effects of the Invention] As is clear from the above description, the present invention forms a ventilation gap along each nice end surface of the stator core between the coil ends of each coil, and also pinches the coil ends on both sides. Therefore, cooling fans are provided to face each other, and the cooling fans are configured to blow cooling air from the outside of the coil ends on both sides through the ventilation gap toward the running gap between the stator cores. The primary stator and the secondary conductor can be efficiently cooled, the deformation of the secondary conductor due to thermal strain and deterioration in starting characteristics can be suppressed, and the running of the secondary conductor can be made smooth. Moreover, improved cooling performance makes it possible to increase the duty ratio of current to the coil and to make it continuous, greatly expanding the range of applications as a linear motor.In addition, the overall device size and cost can be reduced. can be achieved.

[Brief explanation of the drawing]

1 to 7 show a first embodiment of the present invention, and FIG. 1 is a cross-sectional view showing the flow of cooling air when the secondary conductor enters the running gap, and FIG. is a cross-sectional view showing the flow of cooling air when the secondary conductor exits the running gap, Figure 3 is a vertical front view of the main part, Figure 4 is a vertical side view of the same, and Figure 5 is a vertical cross-sectional view of the main part.
The figure shows a partially enlarged side view of the primary stator, FIG. 6 shows a partially enlarged plan view of the stator core, FIG. 7 shows a plan view of the conveyance system, and FIG. 8 shows a second embodiment of the present invention. FIG. 2 is a perspective view of a double-sided linear motor with a cooling fan. 9 to 14 show conventional examples. FIG. 9 is a diagram equivalent to FIG. 7, FIG. 10 is a diagram equivalent to FIG. 3, FIG. 11 is a diagram equivalent to FIG. The figure is a voltage waveform diagram showing the energization cycle to the coil, Figure 13 is a characteristic diagram showing the relationship between the energization time and the temperature of the secondary conductor, and Figure 14 is the relationship between the temperature of the secondary conductor and the starting thrust. It is a characteristic diagram. In the drawing, 12 is a transfer table, 13 is a double-sided linear motor, 6 is a primary stator, 17 is a stator core, 18 is a slot, 19 is a coil, 22 is a running gap, 23 is a secondary conductor, 25 is a coil end, 26 is a ventilation gap, 27 is a tooth, and 28 is a cooling fan. Applicant: Toshiba Corporation

Claims (1)

[Claims] 1. Each coil is housed in each slot of the stator cores on both sides facing each other to form a primary stator, and the secondary conductor is made to run along the running gap between the stator cores on both sides. A ventilation gap is formed along the end face of each tooth of the stator core between the coil ends of each of the coils, and a cooling air gap is provided so as to face each other with the coil ends on both sides in between. and a cooling fan that blows air from the outside of both coil ends through the ventilation gap toward the running gap.