JPS63157643A - Linear motor - Google Patents

Abstract

PURPOSE:To restrict the temperature rise of a coil by winding a pipeline for cooling around the coil for driving. CONSTITUTION:When a plurality of coils 2 is conducted while switching current, a movable piece 1 obtains a thrust and moves into the direction of linear motion. In this case, heat due to Joule's heat is generated in the coil 2 while the heat is transferred to fluid 10, flowing through the pipeline 3. The fluid 10, whose temperature has been risen by the transfer of the heat generated in the coil 2, is transported to a cooler 7 by a pump 6 through the pipeline 3. The cooler 7 deprives heat from the fluid 10, whose temperature has been risen, and the temperature of the fluid is reduced to a predetermined temperature. The predetermined temperature is determined by a control unit 9 based on the temperature of the coil 2, which is detected by a temperature sensor 8. The fluid 10, whose temperature is controlled at the predetermined temperature, is transported to the coil 2 again by the pump 6 through the pipeline 3. Accordingly, the temperature rise of the coil 2 may be restricted and a constant temperature may be maintained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a near motor that is used, for example, as an actuator for an ultra-precision stage, and in which a driving coil is provided with cooling piping.

[Prior Art] Conventionally, as shown in FIG. 5, for example, a moving coil type linear motor has a movable element 1 around which a coil 2 is wound, and a stator in which a permanent magnet 5 is provided on a fixed side yoke 4. has,
A plurality of coils 2 are positioned so as to be sandwiched between the permanent magnets 5.

In the linear motor having such a configuration, thrust is obtained by sequentially switching the current flowing through the plurality of coils 2.

[Problem that the invention seeks to solve] However,
In the above conventional example, when current is applied to coil 2, coil 2
Since the heat generated by the coil 2 was radiated only by the cooling effect of natural cooling, the temperature of the coil 2 rose, causing the following inconvenience.

('1) When a linear motor is attached to a precision machine, the linear motor becomes a heat source, causing thermal deformation of the structure and loss of precision.

(2) The electrical characteristics of the linear motor change as the temperature of the coil increases.

(3) The temperature of the permanent magnet attached to the yoke increases, which shortens the life of the magnet.

In view of the problems in the conventional example described above, the present invention effectively prevents the temperature rise of the drive coil in a linear motor, suppresses thermal deformation of the driven object, and improves the electrical characteristics and reliability of the linear motor itself. The purpose is to improve.

According to the present invention, piping means for transporting heat to the drive coil section which is a heat generation source is provided, and a heat transfer medium is caused to flow through this piping.
A near motor is provided to suppress the temperature rise in the heat source and its vicinity.

As the heat transfer medium, for example, a liquid such as water, a gas such as air, or another fluid is used.

With such a configuration, Joule heat generated in the drive coil section is extracted by the fluid in the piping, and heat generation in the coil section is suppressed.

[Embodiment] FIG. 1 shows a moving coil type linear motor according to an embodiment of the present invention. The linear motor in the figure has a movable element 1 that moves linearly.
, a coil 2 wound around a movable element 1, a pipe 3 wound around the outside of the coil 2, and a yoke 4 constituting a stator. The piping 3 allows a temperature-controlled fluid to flow therethrough.

FIG. 2 is a sectional view taken along the line AA' in FIG. 1, and shows that a plurality of permanent magnets 5 are attached to the inside of the yoke 4.

FIG. 3 is a conceptual diagram of a cooling device for the coil 2. The cooling device shown in the figure is based on a pump 6 for transporting fluid, a cooler 7 for removing heat from the fluid, a temperature sensor 8 for detecting the temperature of the coil, and a temperature of the coil 2 detected by the temperature sensor 8. It is composed of a control device 9 that controls the cooler 7 and the like.

In the above configuration, when current is passed through the plurality of coils 2 while being switched, the movable element 1 obtains thrust and moves in the linear motion direction X. At this time, the coil 2 generates heat due to Joule heat, and this heat is transferred to the fluid 10 flowing through the pipe 3 via the pipe 3. The fluid 10 whose temperature has increased due to the transfer of the heat generated by the coil 2 is transported to the cooler 7 through the pipe 3 by the pump 6 . The cooler 7 removes heat from the fluid 16 whose temperature has increased and lowers the fluid temperature to a predetermined temperature. This predetermined temperature is determined by the control device 9 based on the temperature of the coil 2 detected by the temperature sensor 8. The fluid 10 controlled at a predetermined temperature by the cooler 7 is supplied to the pump 6
It passes through the pipe 3 and is transported to the coil 2 again.

With the circulation mechanism as described above, the rise in temperature of the coil 2 can be suppressed and the temperature can be maintained at a constant temperature. Therefore, (1) thermal deformation of the mover 1 and the coil 2 can be suppressed;
) The electrical characteristics of the linear motor are stabilized, and (3
) is a vertical cross-sectional view showing how the life of the magnet is increased.

In the linear motor shown in the figure, a pipe 3' is further provided between the coil 2 and the movable element 1. Piping 3' is piping 3
Similarly, a temperature-controlled fluid flows through it.

In this embodiment, the Joule heat generated when a current is applied to the coil 2 and the coil 2 is turned on is transmitted to the fluid via the pipes 3 and 3', so that the temperature rise in the coil 2 can be suppressed more effectively. .

[Effects of the Invention] As explained above, according to the present invention, by wrapping the cooling pipe around the drive coil of the linear motor,
The temperature rise of the coil can be effectively suppressed. Therefore, it has the effect of suppressing thermal deformation of the structure to which the linear motor is attached, keeping the electrical characteristics of the linear motor stable, and extending the life of the permanent magnet of the linear motor.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of a linear motor according to an embodiment of the present invention, Fig. 2 is a cross-sectional view taken along line AA' in Fig. 1, and Fig. 3 is a cooling device used in the linear motor of Fig. 1. FIG. 4 is a vertical sectional view showing a linear near motor as another embodiment, and FIG. 5 is a longitudinal sectional view showing a conventional linear near motor. In these figures, 1 is a mover, 2 is a coil, 3 and 3' are pipes, 4 is a yoke, 5 is a permanent magnet, 6 is a pump, 7 is a cooler, 8 is a temperature sensor, and 9 is a control device. Patent Applicant Canon Co., Ltd. Agent Patent Attorney Tatsuo Ito Agent Patent Attorney Satoshi Ito Kozutsu Figure 2 Figure 3

Claims (1)

[Claims] 1. A stator mover, at least one of the stator or the mover has a driving electromagnet, and cooling piping is provided so as to be in contact with the coil part of the driving electromagnet, and the piping A linear motor characterized in that heat generated in the coil portion is removed by a heat transmission medium flowing inside.