JP5072064B2 - Cylindrical linear motor - Google Patents

Description

  The present invention relates to a cylindrical linear motor having an armature core.

  In recent years, a cylindrical linear motor has attracted attention as an actuator for linear reciprocating drive. This cylindrical linear motor is also referred to as a “shaft motor”, and a mover having a plurality of coils is fixed outside the shaft-like stator that alternately generates N-pole and S-pole magnetic fluxes. The mover is linearly driven along the stator by arranging it concentrically with the child, detecting the position of the magnetic pole of the stator with a magnetic sensor (Hall element) provided on the mover, and switching the current to the coil. Many are configured to do so.

  As shown in Patent Document 1 (Japanese Patent Laid-Open No. 2002-354780), this cylindrical linear motor has a core type with an armature core, and Patent Document 2 (WO 2006/011614). There are coreless types without armature cores. In any type, when heat generation due to energization of the coil of the mover becomes a problem, it is necessary to take cooling measures so that the temperature of the coil does not exceed the allowable temperature.

  Therefore, in the cylindrical linear motor with a core of Patent Document 1, a coolant channel is formed at the four corners of the outer frame that houses the armature core, and the mover is cooled by flowing the coolant through the coolant channel. I am doing so.

Further, in the coreless type cylindrical linear motor of Patent Document 2, a plate-like heat pipe is attached so as to be in close contact with the outer peripheral surface of the coil of the mover so that the coil is directly cooled.
JP 2002-354780 A WO2006 / 011614

  In the cooling structure of the cored cylindrical linear motor of Patent Document 1, the outer frame is cooled by flowing a refrigerant through the refrigerant flow path of the outer frame that houses the armature core, and the cooling effect results in the armature core. Since the coil is cooled by the cooling effect, it is necessary to continue cooling the outer frame and the armature core to a temperature somewhat lower than the allowable temperature of the coil. For this reason, the outer frame and the armature core need to continue to be cooled to a temperature somewhat lower than the allowable temperature of the coil, even though there is no problem even if the temperature is higher than that of the coil. Moreover, since the coil is indirectly cooled via the outer frame and the armature core (further, the armature core formed of the laminated steel sheet has poor thermal conductivity), there is a disadvantage that the cooling efficiency of the coil is poor. In addition, a system for circulating the refrigerant in the refrigerant flow path of the outer frame is required, and there is a disadvantage that the configuration is complicated and the cost is increased.

  On the other hand, the cooling structure of the coreless type cylindrical linear motor of Patent Document 2 has a configuration in which a plate-like heat pipe is brought into close contact with the outer peripheral surface of the coil to directly cool the coil, and thus has an advantage of high coil cooling efficiency. is there. However, the coreless type has the disadvantages that the motor efficiency is lower and the power consumption is larger than the coreless type.

  When the cooling technology using the plate-shaped heat pipe of Patent Document 2 is applied to a cylindrical linear motor with a core, a configuration in which the plate-shaped heat pipe is brought into close contact with the outer peripheral surface of the outer frame or the armature core can be considered. However, even in this configuration, since the coil is indirectly cooled through the outer frame and the armature core, there is a drawback that the cooling efficiency of the coil is poor.

  The present invention has been made in view of such circumstances. Accordingly, an object of the present invention is to enable a coil to be efficiently cooled with a simple configuration in a cylindrical linear motor with a core.

In order to achieve the above object, the invention according to claim 1 is a movable body in which a shaft-shaped stator that alternately generates N-pole and S-pole magnetic fluxes and a plurality of coils mounted on the inner peripheral side of the armature core. The movable element is arranged on the outer peripheral side of the stator so as to be movable in the axial direction, and switching the energization to the plurality of coils according to the movement position of the movable element, the movable element is In a cylindrical linear motor that linearly drives along a stator, the armature core is configured by connecting a pair of semi-cylindrical cores with annular holders at both axial ends thereof, and the armature core and the coil In between, as a cooling means, a high thermal conductivity member having a higher thermal conductivity than the armature core is disposed so as not to hinder the flow of magnetic flux inside the armature core, and between the pair of semi-cylindrical cores. , The heat dissipating part of the high thermal conductive member Two gaps for projecting is obtained by a structure provided so as to extend in the axial direction.

According to a cylindrical linear motor of cored type of the present invention, between the armature core and the coil, because it provided a cooling means, can the coil directly cooled by the cooling means, the coil with a simple structure Can be efficiently cooled, and the cooling means does not hinder the flow of magnetic flux inside the armature core, so that the motor efficiency does not need to be reduced.

In addition , a high heat conductive member having a higher thermal conductivity than the armature core (iron) is disposed as a cooling means between the armature core and the coil, and a part of the high heat conductive member is disposed outside the mover. Since the heat radiating portion is formed by being exposed, the heat generated by the coil can be efficiently radiated from the heat radiating portion by the high heat conduction action of the high heat conducting member.
In the cylindrical linear motor of the present invention, two gaps are provided between the pair of semi-cylindrical cores constituting the armature core so that the heat radiating portion of the high thermal conductive member protrudes outside the mover. The flow of magnetic flux inside the armature core circulates along the axial direction and the radial direction (radial direction), not in the circumferential direction (outer circumferential direction) of the armature core. Therefore, the flow of magnetic flux inside the armature core is not interrupted by the gap extending in the axial direction, and the heat radiating part of the high heat conduction member is projected outside the mover without reducing the motor efficiency. Can do.
In this case, as in claim 2, another high thermal conductive member is provided between one half cylindrical core and the coil of the pair of semicylindrical cores and between the other half cylindrical core and the coil. It is good also as a structure which pinched | interposed the heat absorption part and protruded the thermal radiation part of each high heat conductive member to the exterior of a needle | mover from the clearance gap on the opposite side.

  Here, the high thermal conductivity member may be a metal material having a high thermal conductivity such as aluminum, copper, silver or the like (the thermal conductivity of copper is about five times that of iron) or high thermal conductivity. Specialized metal materials may be used.

  Or you may use a heat pipe as a highly heat-conductive member like Claim 3. If a heat pipe is used, extremely high cooling efficiency can be realized.

  According to another aspect of the present invention, the cooling means (high heat conduction member) may be divided into each coil mounting slot formed in the armature core and mounted in the slot. In this way, the cooling means (high heat conduction member) is sandwiched between the coil mounted in the slot of the armature core and the inner peripheral surface of the slot, and the cooling means (high heat conduction) is established between the coil and the inner peripheral surface of the slot. It is possible to assemble in close contact with the member), the assembly work of the cooling means (high heat conduction member) to the armature core is simple, the coil, the cooling means (high heat conduction member), the armature core, It is possible to improve the heat transferability between them and thus the cooling performance.

  Hereinafter, two Examples 1 and 2, which embody the best mode for carrying out the present invention, will be described.

  A first embodiment of the present invention will be described with reference to FIGS. Here, FIG. 1 is a front view showing a part of a mover and a stator of a cylindrical linear motor in a broken state, and FIG. 2 is a longitudinal front view for explaining the configuration of a magnetic circuit and cooling means of the cylindrical linear motor. 3 is a longitudinal side view of the movable element and the stator of the cylindrical linear motor, and FIG.

  As shown in FIGS. 1 and 2, a stator 11 of a cylindrical linear motor includes a plurality of annular permanent magnets in the axial direction on an outer peripheral surface of a cylindrical shaft 12 formed of a magnetic material such as iron. 13 are arranged at equal intervals and fixed by bonding or the like. Each permanent magnet 13 is formed in an annular shape by combining a plurality of arc-shaped magnet pieces (see FIG. 3), and as shown in FIG. 2, the permanent magnet 13 whose outer peripheral surface is magnetized to N pole, Permanent magnets 13 whose surface side is magnetized to S poles are alternately arranged. In FIG. 1, only the magnetic poles on the outer peripheral surface side of the permanent magnet 13 are indicated by “N” and “S”.

  A cylindrical movable element 14 is provided on the shaft-shaped stator 11 so as to be movable in the axial direction. The cylindrical mover 14 is configured by attaching coils 17 to a plurality of circular groove-like slots 16 formed at equal intervals in the axial direction on the inner peripheral portion of a cylindrical armature core 15. In order to avoid collision between the inner peripheral surface of the child 14 (the inner peripheral surface of the armature core 15 and the inner peripheral surface of the coil 17) and the outer peripheral surface of the stator 11 (the outer peripheral surface of the permanent magnet 13). The air gap (air gap) is provided. The cylindrical armature core 15 is configured by connecting a pair of semi-cylindrical cores 15a and 15b formed of a magnetic material such as iron by an annular holder 18 at both axial ends thereof, and the pair of semi-cylindrical cores 15a and 15b. In between, two gaps 20 are provided so as to extend in the axial direction for projecting a heat radiating portion 19b of a plate-shaped heat pipe 19 to be described later to the outside of the mover.

  A plate-like heat pipe 19 (high heat conduction member) is fitted into the back of each slot 16 of the armature core 15, and each heat pipe 19 is sandwiched between the coil 17 and the armature core 15. They are in close contact with both. Each heat pipe 19 has a pipe portion made of a metal material having high thermal conductivity such as aluminum or magnesium, and a working fluid (heat exchange medium) such as butane, water, freon, ammonia in the pores formed therein. It is configured to enclose.

As shown in FIG. 3, two heat pipes 19 are provided for each coil 17, and a portion of each heat pipe 19 that is in close contact with the coil 17 becomes a heat absorbing portion 19 a, and a heat radiating portion 19 b that extends on the opposite side is provided. The armature core 15 projects outward from the gap 20. In the present embodiment, as shown in FIG. 3, between one semi-cylindrical core 15 a and the coil 17 of the pair of semi-cylindrical cores 15 a and 15 b, and between the other semi-cylindrical core 15 b and the coil 17. The heat absorbing portions 19a of the different heat pipes 19 are sandwiched between them, and the heat radiating portions 19b of the heat pipes 19 protrude from the gaps 20 on the opposite sides to the outside of the mover 14. Furthermore, in order to enhance the heat dissipation effect, heat dissipation fins 21 made of a metal material with high thermal conductivity are attached to the heat dissipation portion 19b of each heat pipe 19 by welding, brazing or the like. Note that a heat sink may be attached instead of the heat radiating fins 21 or a cooling fan may be attached.

  In the first embodiment described above, the plate-like heat pipe 19 serving as a cooling means for cooling the coil 17 is provided for each slot 16 so as not to disturb the flow of magnetic flux inside the armature core 15 (see FIG. 2). The heat pipe 19 is divided and mounted in the slot 16 of the armature core 15, and the heat pipe 19 is sandwiched between the coil 17 and the armature core 15 so as to be in close contact with both. In this configuration, the assembly of the heat pipe 19 to the armature core 15 is simple, and unlike the Patent Document 2, the coil 17 can be directly cooled by the heat pipe 19, and the coil can be configured with a simple configuration. 17 can be efficiently cooled, and the armature core 15 can also be efficiently cooled by the heat pipe 19. In addition, since the heat pipe 19 is divided and attached to each slot 16, the heat pipe 19 does not block the flow of magnetic flux inside the armature core 15 (see FIG. 2), and the motor efficiency is not lowered. It will end.

  In the first embodiment, between the pair of semi-cylindrical cores 15 a and 15 b constituting the cylindrical armature core 15, two heat-radiating portions 19 b of the heat pipe 19 are projected to the outside of the mover 14. However, as shown in FIG. 2, the flow of magnetic flux inside the armature core 15 is not the flow in the circumferential direction (outer peripheral direction) of the armature core 15. Since the flow circulates along the axial direction and the radial direction (radial direction), the magnetic flux flow inside the armature core 15 is not divided by the gap 20 extending in the axial direction, and the motor efficiency is not lowered. It will end.

In the first embodiment, the pair of semi-cylindrical cores 15a and 15b constituting the armature core 15 are formed as one body, but in the second embodiment of the present invention shown in FIG. The semi-cylindrical cores 25a and 25b are divided into an inner peripheral side and an outer peripheral side, respectively, and a semi-annular portion for forming a slot 26 on the inner peripheral side of the semi-cylindrical portions 25a1 and 25b1 on the outer peripheral side. A pair of semi-cylindrical cores 25a and 25b having slots 26 are formed by fixing 25a2 and 25b2 by welding, brazing, screwing or the like, and the pair of semi-cylindrical cores 25a and 25b is circular at both axial ends thereof. A cylindrical armature core 25 is configured by being connected by an annular holder 18. Other configurations are the same as those of the first embodiment.
Even in the second embodiment configured as described above, the same effects as in the first embodiment can be obtained.

  In the first and second embodiments, the plate-like heat pipe 19 is used as a cooling means for cooling the coil 17, but the present invention is not limited to this, and a magnetic material such as iron forming the armature core 15. For example, a metal material having a high thermal conductivity such as aluminum, copper, or silver may be used as long as it has a higher thermal conductivity than copper (the thermal conductivity of copper is about five times that of iron). Alternatively, a special metal material with high thermal conductivity may be used.

  In the first and second embodiments, the heat pipe 19 is brought into close contact with the inner portions of the slots 16 and 26 of the armature core 15, but heat is applied to both side portions or one side portion of the slots 16 and 26. The pipe 19 may be in close contact, and of course, the heat pipe 19 may be in close contact with both the back and side portions of the slots 16 and 26.

  In addition, according to the present invention, the non-magnetic spacer is interposed between the permanent magnets 13 to regulate the interval between the permanent magnets 13, or the armature cores 15 and 25 may be formed of laminated steel plates. 11 and the structure of the mover 14 may be changed as appropriate.

It is a front view which fractures | ruptures and shows a part of mover and stator of the cylindrical linear motor of Example 1 of this invention. It is a vertical front view explaining the structure of the magnetic circuit of the cylindrical linear motor of Example 1, and a cooling means. It is a vertical side view of the movable element and stator of the cylindrical linear motor of Example 1. FIG. 3 is a plan view illustrating a part of a mover and a stator of the cylindrical linear motor according to the first embodiment. It is a front view which fractures | ruptures and shows a part of needle | mover of a cylindrical linear motor of Example 2, and a stator.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Stator, 12 ... Shaft, 13 ... Permanent magnet, 14 ... Movable element, 15 ... Armature core, 15a, 15b ... Semi-cylindrical core, 16 ... Slot, 17 ... Coil, 19 ... Plate-shaped heat pipe (cooling) Means, high heat conduction member), 19a ... heat absorption part, 19b ... heat radiation part, 21 ... heat radiation fin, 25 ... armature core, 25a, 25b ... semi-cylindrical core, 26 ... slot

Claims (4)

A shaft-like stator that alternately generates N-pole and S-pole magnetic flux; and a mover having a plurality of coils mounted on the inner peripheral side of the armature core; and the mover on the outer peripheral side of the stator In a cylindrical linear motor that is arranged so as to be movable in the axial direction and linearly drives the mover along the stator by switching energization to the plurality of coils according to the moving position of the mover.
The armature core is configured by connecting a pair of semi-cylindrical cores with an annular holder at both axial ends thereof,
Between the armature core and the coil, as a cooling means, a high thermal conductivity member having a higher thermal conductivity than the armature core is disposed so as not to disturb the flow of magnetic flux inside the armature core ,
Between the pair of semi-cylindrical cores, there is provided a cylindrical shape in which two gaps for projecting the heat radiating portion of the high heat conducting member to the outside of the mover extend in the axial direction. Linear motor. A heat absorbing portion of another high heat conductive member is sandwiched between one half cylindrical core of the pair of semicylindrical cores and the coil, and between the other semicylindrical core and the coil. 2. The cylindrical linear motor according to claim 1, wherein a heat radiating portion of the conductive member protrudes from the gaps on opposite sides to the outside of the mover .   The cylindrical linear motor according to claim 2, wherein the high heat conductive member is configured by a heat pipe. 4. The cylindrical type according to claim 1, wherein the high heat conductive member is divided into slots for mounting coils formed in the armature core and mounted in the slots. 5. Linear motor.

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