JP2008048562A - Linear motor and machine tool mounting it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a linear motor in which a coil case can be cooled from the circumference even if an opening for wire connection is formed in the coil case and cooling efficiency can be enhanced. <P>SOLUTION: The linear motor comprises a shaft member 2 consisting of permanent magnets where N poles and S poles are arranged alternately, and a coil unit 3 where a plurality of coils 6 surrounding the shaft member 2 are arranged in the axial direction. The coil unit 3 has a tubular coil case 7 containing the plurality of coils 6. An opening 15 for wire connection is formed in the coil case 7 across the plurality of coils 6 in order to introduce the coil windings of the plurality of coils 6 to the outside of the coil case 7. In the outer circumferential part of the coil case 7, a plurality of independent cooling channels 17a for feeding cooling medium are provided at positions other than the opening 15 for wire connection. The cooling channels 17a are extending in the axial direction. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a linear motor and a machine tool such as a press machine equipped with the linear motor.

  2. Description of the Related Art Conventionally, a linear motor having a shaft member made of permanent magnets in which N poles and S poles are alternately arranged and a coil unit in which a plurality of coils surrounding the shaft member are arranged in the axial direction has been proposed. (For example, patent document 1).

Further, like a stator 63 of a rotary motor shown in FIG. 10, a coil 66 is wound in the longitudinal direction, and in a motor in which a plurality of coil pieces are arranged in the circumferential direction, a cylindrical coil case 67 is provided. As a double structure, there is one in which a spiral cooling flow path 68 is provided on the fitting surface, and forced cooling is performed with cooling water.
Japanese Patent Laid-Open No. 10-313566

The linear motor disclosed in Patent Document 1 is used in place of a combination of a rotary motor and a ball screw in OA equipment or the like, but also in a machine tool that performs a linear motion such as a press machine. When a linear motor is used, the configuration is simple and the controllability is excellent.
However, when a linear motor is used in a press machine or the like, it is necessary to obtain a large thrust, and thus heat generation of the coil increases. In particular, when the plurality of coils are accommodated in a cylindrical coil case, the coil unit can be firmly configured and is suitable for a machine tool. However, heat is trapped in the coil unit, and the temperature of the coil unit increases. Becomes larger. A large temperature rise of the coil unit affects the efficiency reduction of the linear motor due to the demagnetizing action of the permanent magnet, and also affects the safety to the operator. In addition, when the coil unit is used in a machine tool, a large temperature rise of the coil unit deteriorates processing accuracy due to heat transmitted from the linear motor to the frame, for example, a punch and die are misaligned in a punch press. Therefore, it is necessary to efficiently radiate the heat generated by the coil.

Providing the spiral cooling flow path 68 as in the example of FIG. 10 is advantageous in terms of cooling efficiency. However, in a coil unit in which a plurality of coils are arranged in the axial direction, a connection opening for guiding the coil winding of each coil to the outside is formed across the plurality of coils in a cylindrical coil case. There is a need.
When providing a connection opening spanning a plurality of coils in this way, the spiral cooling flow path 68 as in the example of FIG. 10 interferes with the connection opening, so that the region should be provided continuously. I can't do it and it breaks. Therefore, a cooling structure that can perform efficient cooling even if there is an opening for connection is desired. When a jacket-type cooling path is adopted in which the coil case is doubled and the entire circumference is a single hollow space, the seal around the connection opening becomes complicated, and a partition for forming a cooling flow path inside the jacket is provided. Necessary.

The object of the present invention is that even if a connection opening is formed in the coil case, the coil case can be cooled from the surroundings, can be cooled evenly, and the flow rate of the cooling medium can be reduced, thereby improving the cooling efficiency. An object of the present invention is to provide a linear motor that can handle the above.
Another object of the present invention is to provide a linear motor-equipped machine tool that has a simple structure with a small number of parts, suppresses heat generation in the motor, and has excellent machining accuracy.

  In the linear motor of the present invention, a shaft member made of permanent magnets in which N poles and S poles are alternately arranged, and a plurality of coils surrounding the periphery of the shaft member are arranged in the axial direction, and the shaft member relatively moves inside. An axially movable coil unit, wherein the coil unit has a cylindrical coil case that houses the plurality of coils, and the coil case is a coil winding of the plurality of coils. A wiring opening for guiding the outside of the coil case is formed across the plurality of coils, and a plurality of independent cooling flow paths through which a cooling medium flows are provided on the outer periphery of the coil case. It is characterized in that it is provided at a position where the part is removed.

  According to this configuration, since a plurality of independent cooling channels are provided on the outer periphery of the coil case at a position where the connection opening is removed, efficient cooling can be performed even if the connection opening is present. That is, since a plurality of cooling channels are provided independently from each other, unlike the jacket-type cooling channel or the like, there is no need for a seal around the opening for connection, and there is no partition in the jacket. The cooling medium can be made to flow evenly. Therefore, even when applied to machine tools and other linear motors that require high output, the necessary cooling efficiency can be ensured.

Each of the plurality of cooling channels may be provided along the axial direction of the coil unit.
When each cooling channel is along the axial direction, the cooling channel can be configured simply.

A linear motor-equipped machine tool according to the present invention includes the linear motor having any one of the above-described configurations according to the present invention and a movable portion that is moved forward and backward by the linear motor to move a tool or a workpiece. The term “machine tool” as used in this specification is not limited to a machine that performs cutting such as a lathe, but is a general machine tool that indicates a general machine for processing an object, and includes a punch press and other press machines. is there.
According to this configuration, since the movable portion that moves forward and backward is driven by a linear motor, a mechanism that converts rotation into linear motion is not required, unlike a rotary type motor, and a simple structure with fewer parts can be achieved. . Further, by using the linear motor of the present invention, the motor generates less heat and has excellent processing accuracy.

In the linear motor of the present invention, a shaft member made of permanent magnets in which N poles and S poles are alternately arranged, and a plurality of coils surrounding the periphery of the shaft member are arranged in the axial direction, and the shaft member relatively moves inside. An axially movable coil unit, and the coil unit has a cylindrical coil case containing the plurality of coils, and the coil case has coil windings of the plurality of coils outside the coil case. A connection opening for guiding is formed across a plurality of coils, and a plurality of independent cooling channels through which a cooling medium flows are removed from the outer periphery of the coil case, the position where the connection opening is removed. Even if the connection opening is formed in the coil case, the coil case can be cooled from the surroundings, can be cooled without unevenness, and without providing a partition inside the jacket, It is possible to increase the 却効 rate. Therefore, even when applied to machine tools and other linear motors that require high output, the necessary cooling efficiency can be ensured.
When the plurality of cooling channels are provided along the axial direction of the coil unit, it is much easier to design a channel with good cooling efficiency.
The machine tool equipped with the linear motor according to the present invention comprises the linear motor according to the present invention and a movable part that is moved forward and backward by the linear motor to move the tool or the workpiece. The heat generation in the motor is small and the processing accuracy is excellent.

  A first embodiment of the present invention will be described with reference to FIGS. The linear motor 1 includes a shaft member 2 made of permanent magnets in which N poles and S poles are alternately arranged, and a coil unit 3 that surrounds the periphery of the shaft member 2 and in which the shaft member 2 is relatively movable in the axial direction. With. The coil unit 3 serves as a stator, and the shaft member 2 serves as a moving body. The shaft member 2 may be a stator.

  The shaft member 2 has sliders 4 and 5 attached to both ends of a shaft member main body 2a made of a round bar-like permanent magnet.

  The coil unit 3 is configured by arranging a plurality of cylindrical coils 6 surrounding the shaft member 2 in the axial direction. The plurality of coils 6 are accommodated in a common cylindrical coil case 7, and caps 8 and 9 are attached to both ends of the coil case 7 to form a coil unit 3.

A ring-shaped heat sink 11 is interposed between the coils 6. The heat sink 11 is also disposed at both ends of the coil 6 array. These heat sinks 11 are brought into contact with the inner peripheral surface of the coil case 7. Each coil 6 is on the outer periphery of a common cylindrical coil bobbin 10. The coil 6 is inserted into the coil case 7 in the axial direction with the coil bobbin 10 inserted in this manner. The plurality of coils 6 are molded and integrated with the heat sink 11 in the coil case 7.
A wiring 14 (see FIGS. 2 and 3) connecting the plurality of coils 6 is taken out from a connection opening 15 provided in the coil case 7. The connection opening 15 has a long hole shape extending in the axial direction across the plurality of coils 6.

As shown in FIG. 1, the inner periphery of caps 8 and 9 attached to both ends of the coil case 7 is cylindrical as a slide bearing that is slidably fitted to sliders 4 and 5 attached to both ends of the shaft member 2. A shaped bush 12 is provided. The caps 8 and 9 have a cylindrical shape with an inner peripheral surface, the sliders 4 and 5 have a shaft shape with an outer peripheral surface, and the bush 12 is provided on the inner peripheral surface on the large diameter side of the caps 8 and 9. It has been. Further, the caps 8 and 9 are provided with stoppers 13 for stopping the sliders 4 and 5 by hitting the stepped portions of the sliders 4 and 5. The bush 12 holds a minute gap that allows relative movement between the shaft member 2 and the coil unit 3. That is, between the inner peripheral surface of the coil bobbin 10 of the coil 6 and the outer peripheral surface of the shaft member 2, and the outer peripheral surfaces of the small diameter portions 4 a and 5 a of the sliders 4 and 5 attached to both ends of the shaft member 2 and the caps 8 and 9. A minute gap for axial movement is maintained between the small diameter side inner peripheral surfaces 8a and 9a.
In addition, the holding means for the gap between the shaft member 2 and the coil unit 3 is not necessarily provided in the linear motor, and the holding means for the gap may be provided in a device using the linear motor.

  A forced cooling unit 16 is provided on the outer periphery of the coil case 7. The forced cooling unit 16 is configured by arranging a plurality of cooling pipes 17 extending in the axial direction at equal intervals in the circumferential direction. The position of the cooling pipe 17 in the circumferential direction of the coil case is a position where the connection opening 15 is removed. The cooling pipes 17 constitute a plurality of cooling channels 17 a that are independent from each other on the outer periphery of the coil case 7. The cooling pipe 17 is a pipe through which a cooling medium such as water or other cooling liquid flows.

  Each cooling pipe 17 is held by a cooling pipe holding portion 18 (FIGS. 3 and 6) provided integrally with the coil case 7. The cooling pipe holding portion 18 is formed of a bifurcated protruding piece that holds the cooling pipe 17 from both sides, and extends in the axial direction over the entire length of the coil case 7. The cooling pipe 17 is held by being inserted into the cooling pipe holding part 18 in the axial direction. The coil case 7 is made of an extruded product of aluminum.

  Both ends of each cooling pipe 17 communicate with annular collecting paths 20 and 21 provided in caps 8 and 9 at both ends of the coil case 7, respectively. Each of the collecting paths 20 and 21 is formed by annular grooves 20a and 21a by dividing the caps 8 and 9 into cap bodies 8A and 9A and ring members 8B and 9B. That is, annular inner diameter enlarged portions 8Aa, 9Aa are formed on the inner periphery of the coil side end of each cap body 8A, 9A, and the annular grooves 20a, 21a are formed on the inner peripheral surfaces of the inner diameter enlarged portions 8Aa, 9Aa. Then, by fitting the ring members 8B and 9B to the inner diameter enlarged portions 8Aa and 9Aa, a collective path having a closed cross section having a rectangular cross section between the annular grooves 20a and 21a and the outer peripheral surfaces of the ring members 8B and 9B. 20 and 21 are formed. In the ring members 8B and 9B, the end of the coil case 7 is fitted to the outer periphery, and the end of the coil bobbin 10 is fitted to the inner periphery.

  An annular groove is formed on the inner peripheral surface of the inner diameter enlarged portions 8Aa and 9Aa of the cap bodies 8A and 9A and the fitting surface of the ring members 8B and 9B on both sides in the axial direction of the collecting paths 20 and 21 to form an O-ring. The collecting paths 20 and 21 are sealed by interposing seal members 22 and 23 made of, for example.

  A plurality of cooling pipe fitting holes 24 and 25 for fitting both ends of the cooling pipes 17 are formed in the caps 8 and 9 so as to penetrate the collecting paths 20 and 21 from the end faces of the caps. Seal members 26 and 27 made of an annular elastic body are interposed between the inner peripheral surfaces of the cooling pipe fitting holes 24 and 25 and the outer peripheral surface of the cooling pipe 17 fitted thereto. These seal members 26 and 27 are O-rings and are held in annular grooves 28 and 29 formed on the inner peripheral surfaces of the cooling pipe fitting holes 24 and 25.

  The depth including the collecting paths 20 and 21 of the cooling pipe fitting holes 24 and 25 needs to be deeper than the maximum insertion allowance of the cooling pipe 17 into the caps 8 and 9. The maximum insertion allowance here refers to an insert allowance including processing errors, assembly errors, and fluctuation factors such as thermal expansion and contraction. In this embodiment, the insertion allowance of the cooling pipe 17 to the caps 8 and 9 is a range in which the cooling pipe 17 does not protrude into the collecting paths 20 and 21 even if processing, assembly errors, thermal expansion and contraction are taken into consideration. Yes.

  The collecting paths 20 and 21 provided on the caps 8 and 9 on both sides are connected to the external pipe 30 via a joint 29 as shown in an enlarged view in FIG. The external pipe 30 is connected to a cooling medium supply device (not shown) having a pump for circulating a cooling medium such as a cooling liquid. One of the collecting paths 20 and 21 on both sides is the cooling medium supply side and the other is the discharge side.

  According to the linear motor of this configuration, the plurality of cooling channels 17a that are independent from each other are provided in the outer peripheral portion of the coil case 7 at the position where the connection opening 15 is removed. Efficient cooling can be performed. That is, since the plurality of cooling channels 17a are provided independently of each other, unlike the jacket-type cooling channel or the like, there is no need for a seal around the connection opening 15 and the cooling medium is provided without providing a partition in the jacket. It can flow evenly. Therefore, even when applied to machine tools and other linear motors that require high output, the necessary cooling efficiency can be ensured. Since each cooling flow path 17a consists of the cooling pipe 17 along the axial direction of the coil unit 3, it becomes a simple structure.

In addition, each cooling pipe 17 is sealed at the peripheral surface because both ends are fitted in the cooling pipe fitting holes 24 and 25 provided in the caps 8 and 9 at both ends of the coil case 1, and the butted surfaces Unlike the case where the sealing is performed, even if each cooling pipe 17 has a dimensional variation, a reliable sealing can be performed without being affected by the dimensional variation.
Further, since the individual cooling pipes 17 are sealed by the interposition of sealing members 26 and 27 made of an annular elastic body such as an O-ring, a more reliable sealing can be performed.

  FIG. 8 shows another embodiment of the present invention. In this embodiment, instead of providing the cooling pipe 17 in the first embodiment shown in FIGS. 1 to 7, the coil case 7 is provided with a cooling flow path forming wall 17 </ b> A, and the inside thereof is referred to as a cooling flow path 17 </ b> Aa. It is a thing. The cooling flow path forming wall 17 </ b> A extends the entire length of the coil case 7, is equally distributed at a plurality of locations in the circumferential direction, and is provided at a position where the connection openings 15 are removed. The coil case 7 having such an integrally structured cooling flow path forming wall 17A can be formed by, for example, an extruded product of aluminum.

Both ends of each cooling flow path 17Aa communicate with the caps 8 and 9 on both sides in alignment with the branch paths 20b and 21b formed corresponding to the respective cooling flow paths 17Aa from the collecting paths 20 and 21, respectively. A ring-shaped seal plate 31 such as a rubber plate is interposed between the butted surfaces of the caps 8 and 9 and the coil case 7 in a sandwiched state.
In this embodiment, the caps 8 and 9 do not have means for guiding the shaft member 2. Other configurations in this embodiment are the same as those in the first embodiment.

  As described above, even when the cooling flow path 17Aa is formed integrally with the coil case 7, the coil case 7 is cooled from the surroundings while the connection opening 15 is formed in the coil case 7 as in the first embodiment. This can increase the cooling efficiency.

  In each of the above embodiments, the cooling flow paths 17 and 17Aa extend in the axial direction of the coil case 7. However, the cooling flow paths 17 and 17Aa include the connection opening 15 of the coil case 7. It may be provided so as to be removed, and for example, it may extend obliquely or may have a meandering shape.

  FIG. 9 shows a press machine which is an example of a machine tool using a linear motor as a drive source. In this press machine, tool supports 42 and 43 and a work feed mechanism 44 are installed at the lower part of the frame 41, and a press mechanism 45 using the linear motor 1 is installed as a press drive source at the upper part of the frame 41. It is.

  The tool supports 42 and 43 are composed of upper and lower turrets arranged concentrically, and the upper and lower tool supports 42 and 43 are equipped with tools that are punch dies and die dies at a plurality of locations in the circumferential direction, respectively. Is done. These punch dies and die dies are indexed to a predetermined punch position P by the rotation of the tool supports 42 and 43. The workpiece feeding mechanism 44 grips the edge of the workpiece W, which is a plate material, with the workpiece holder 47 and moves the workpiece W back and forth and right and left on the table 48.

  The press mechanism 45 supports a ram 49 that lifts and lowers a punch die indexed to a punch position P of the tool support 42 by a ram guide 50 so that the ram 49 can be lifted and lowered by the linear motor 1. is there. For the linear motor 1, for example, the first embodiment described above with reference to FIGS. 1 to 7 or the embodiment shown in FIG. 8 is used. In the linear motor 1, the coil unit 3 is fixed to a frame 41, and the shaft member 2 is coupled to a ram 49 which is a movable portion.

  According to the press machine having this configuration, since the linear motor 1 is used as a press drive source, a mechanism for converting the rotation into the linear motion of the ram 49 is not required as compared with a press motor using a rotary motor. The number of parts is small and the configuration is simple. In addition, a hydraulic unit is not required and the configuration is simpler than that using a hydraulic cylinder as a press drive source. Moreover, the linear motor 1 is excellent in positional accuracy, and processing with high processing quality and accuracy is possible.

  The linear motor of the present invention is not limited to a press machine, and can be used for driving the movable part in general machine tools including a movable part for moving a tool or a workpiece. Furthermore, it can be used not only as a machine tool but as a drive source for various devices.

1 is a longitudinal sectional view of a linear motor according to a first embodiment of the present invention. It is a disassembled perspective view of the coil unit in the linear motor. It is a cross-sectional view of the coil unit. It is an expanded sectional view of the IV section of FIG. It is an expanded sectional view of the joint connection part of the coil unit. It is a fragmentary perspective view which shows the relationship between the coil case of the same coil unit, and a cooling pipe. It is a disassembled perspective view which shows the relationship between the cap of the coil unit, and a cooling pipe. (A) is a longitudinal cross-sectional view which shows the coil unit of the linear motor concerning other embodiment, (B) is the VIII-VIII sectional view taken on the line. It is a side view of the press machine which is a machine tool using the linear motor which concerns on one Embodiment of this invention. It is a partial abbreviation sectional view of the coil unit of the conventional linear motor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Linear motor 2 ... Shaft member 3 ... Coil unit 4, 5 ... Slider 6 ... Coil 7 ... Coil case 8, 9 Cap 8A, 9A ... Cap main body 8B, 9B ... Ring member 10 ... Coil bobbin 14 ... Wiring 15 ... For connection Opening 16 ... Forced cooling part 17 ... Cooling pipe 17a ... Cooling flow path 17A ... Cooling flow path forming wall 17Aa ... Cooling flow path 18 ... Cooling pipe holding parts 20 and 21 ... Collecting paths 24 and 25 ... Cooling pipe fitting holes 26, 27 ... Seal members 28, 29 ... Annular groove 41 ... Frame 45 ... Press mechanism 49 ... Ram (movable part)
W ... Work

Claims (3)

A coil unit in which a shaft member composed of permanent magnets in which N poles and S poles are alternately arranged, and a plurality of coils surrounding the shaft member are arranged in the axial direction, and the shaft member is relatively movable in the axial direction. And
The coil unit has a cylindrical coil case containing the plurality of coils, and the coil case has a plurality of connection openings for guiding the coil windings of the plurality of coils to the outside of the coil case. A linear motor characterized in that a plurality of mutually independent cooling flow paths through which a cooling medium flows are provided at a position where the connection opening is removed, on the outer periphery of the coil case.   The linear motor according to claim 1, wherein each of the plurality of cooling flow paths is provided along an axial direction of the coil unit.   A machine tool equipped with a linear motor, comprising: the linear motor according to claim 1 or 2; and a movable part that is moved forward and backward by the linear motor to move a tool or a workpiece.

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