1. Technical Field The present invention relates to a stator core and a stator applied to a cylinder linear motor.
2. Description of Related Art
A motor is used in various applications. For example, various motors are used for driving industrial robots. Motors include a rotary motor which rotates and a linear motor which moves linearly. As a kind of linear motors, a cylinder linear motor in which a movable element is disposed in a stator and which moves linearly is known (refer to Unexamined Japanese Patent Application Kokai Publication No. 2001-286122).
In a cylinder linear motor disclosed in the patent document, a stator core is formed so that it can be divided in the axial direction. Each of stator divided bodies has an annular disc and an annular projection provided in the outer circumference of the disc. The annular projection projects in the axial direction and has a coupling structure of coupling the outer circumferences of the stator divided bodies. A space surrounded by the projections and the disc is a space (slot) for disposing a winding coil between the stator divided bodies. By the length of the projection, the slot pitch is determined accurately.
In the cylinder linear motor disclosed in the patent document 1, however, the projection formed in each of the stator divided bodies has the coupling structure, so that the shapes of the stator divided bodies are complicated. There is consequently a technical problem of high manufacture cost.
The present invention has been achieved in consideration of the above circumferences and an object of the present invention is to provide, at low cost, a stator core and a stator for a cylinder linear motor, in which slot pitch can be accurately determined.
A stator core for use in a cylinder linear motor includes a positioning rod and a plurality of core bodies. The positioning rod extends in a rod shape, and a plurality of first fitting parts are formed at predetermined intervals in the extension direction in the positioning rod. Each of the plurality of core bodies is formed in a flat plate shape and a hole through which a movable element can be inserted is formed in a direction orthogonal to the flat plate. In an outer circumference of the plurality of core bodies, second fitting parts which fit in the first fitting parts are provided. When the second fitting parts are fit in the first fitting parts, the core bodies are positioned at the predetermined intervals.
Hereinafter, with reference to the appended drawings, embodiments of the present invention will be described. In description of the drawings, the same reference numerals are designated to the same elements and repetitive description will not be given. The dimensional proportions in the drawings may be exaggerated for convenience of explanation and different from the actual proportions.
A cylinder linear motor 10 has a movable element 20 which is a field system and can move linearly and a stator 30 as an armature. Although the cylinder linear motor 10 includes various components such as a sensor and a bearing, the detailed configuration will not be described.
The movable element 20 has a linear motion shaft 21 and magnets 22. The linear motion shaft 21 is supported so as to be linearly reciprocatable. In the periphery of the linear motion shaft 21, a plurality of permanent magnets 22 are attached in the axial direction. The plurality of magnets 22 are attached to the linear motion shaft 21 so that N and S poles are alternately arranged. The linear motion shaft 21 and the magnets 22 are inserted in the stator 30.
The detailed configuration of the stator 30 according to the first embodiment will be described.
As shown in
With reference to
As shown in
As shown in
The end-part core bodies 44 are stacked at both ends of the core assembly 40 as shown in
The winding coil 46 is formed in such a manner that, as shown in
The two winding coils 46 to which the excitation current of the same phase is passed are formed, as shown in
As shown in
The recess 480 is formed by making a part of the column-shaped positioning rod 48 slightly smaller and to have width which is the same as the thickness of the fitting part 422 in the center core body 42. In the recess 480, the fitting part 422 of the center core body 42 can be fit. When the fitting part 422 of the center core body 42 fits in each of the recesses 480, the center core body 42 is positioned according to the intervals of the recesses 480. The predetermined intervals at which the recesses 480 are formed are desired intervals to dispose the center core body 42 and are determined in consideration of the number of turns and the occupation ratio of the winding coil 46. Referring again to
In
Next, a method of assembling the stator 30 will be described.
First, a core member stand 60 shown in
Around the cylindrical part 61 of the core member stand 60, the end-part core body 44 is put. After that, the winding coil 46 and the center core body 42 are alternately put. In the case where the two winding coils 46 share the same conductive wire 462 as shown in
After all of the winding coils 46 are put around the cylindrical part 61 as shown in
As shown in
As shown in
In a state where the core assembly 40 is disposed in the frame 50 as shown in
With the above configuration, the following effects are obtained.
In the first embodiment, when the recess 480 (first fitting part) of the positioning rod 48 and the fitting part 422 (second fitting part) of the center core body 42 are fit, the center core bodies 42 can be easily and accurately positioned according to the predetermined intervals of the recesses 480 of the positioning rod 48. As a result, the slot pitches between the center core bodies and the end-part core bodies 44 can be determined accurately. It is sufficient to form the fitting part 422, for example, in the outer periphery of the disc-shaped center core bodies 42. Therefore, without making the shape of the center core body 42 excessively complicated, the center core body 42 can be manufactured relatively at low cost by, for example, press work or the like.
Since the center core bodies 42 and the end-part core bodies 44 are just disposed in the frame 50, the configuration is simple and manufacture is easy. Since the center core bodies 42 and the end-part core bodies 44 matching the inner peripheral shape of the frame 50 are provided, a magnetic circuit can be reliably closed by the center core bodies 42, the end-part core bodies 44, and the frame 50. Since the magnetic circuit is closed by the frame 50 as a casing, the space for disposing the winding coil 46 can be sufficiently assured. In addition, the winding coils 46 are held between the center core bodies 42 and the end-part core bodies 44 each having the flat plate shape, so that the winding coils 46 are held effortlessly, and the shape is not easily lost.
The housing grooves 51 and 52 are formed in the inner peripheral face of the frame 50, and the positioning rod 48 and the recess 480 can be housed in the housing grooves 51 and 52. Since the housing grooves 51 and 52 are formed at the corners of the frame 50, it is unnecessary to form the frame 50 largely for the housing grooves 51 and 52, and the space can be effectively utilized.
The housing groove 53 is formed in the inner peripheral face of the frame 50, and the conductive wire 462 led from the winding coil 46 can be easily led. Further, since the connection coupling part of the lead wires of the respective phases (U, V, and W) exists in the frame 50, it is reliably protected.
Since the center core body 42 is formed by stacking the plurality of plate members 424, by changing the number of members stacked, a design change such as adjustment of length of the stator 50 and a change in the number of turns of the winding coil 46 can be easily realized. Since all of the plate members 424 have the same shape, they can be formed by the same mold. As a result, the center core bodies 42 can be manufactured at low cost.
The end-part core bodies 44 disposed at both ends of the core assembly 40 are not formed by stacking a plurality of plate members. In the end-part core bodies 44, the diameters of the holes 441 are not constant. Consequently, when the end-part core bodies 44 are formed by stacking plate members like the center core bodies 42, a plurality of molds are necessary. The end-part core bodies 44 formed by cutting without using molds can be manufactured at lower cost.
The notch 423 is provided in the center core body 42, and the conductive wire 462 of the winding coil 46 passes through the notch 423. Therefore, the winding coils 46 on both sides of the center core body 42 can commonly use the same conductive wire 462. Since it is sufficient to manufacture three winding coils 46 in the foregoing embodiment, manufacture of the winding coil 46 is facilitated.
Although the case of using five center core bodies 42 and six winding coils 46 has been described in the first embodiment, the invention is not limited to the case. The numbers can be properly changed.
Although the example of fitting the fitting part 422 of the center core body 42 to the recess 480 formed slightly smaller than the columnar positioning rod 48 has been described, the invention is not limited to the example. The recess 480 may be formed by parallely cutting (D cutting) a part of the columnar positioning rod 48. The positioning rod 48 is not limited to the columnar shape but may have a prism shape. As long as slot pitches among a plurality of center core bodies 42 and slot pitches between the center core body 42 and the end-part core body 44 can be positioned by combining at least shapes (first fitting parts) formed at predetermined interval in the positioning rod 48 and shapes (second fitting parts) formed in the outer periphery of the center core body 42, the first and second fitting parts may have arbitrary shapes.
A precondition of a second embodiment is the configuration of the first embodiment, and the second embodiment has a configuration almost similar to that of the first embodiment. In the following, therefore, a configuration different from that of the first embodiment will be mainly described. The same reference numerals are used for configurations similar to those of the first embodiment and their description will not be repeated. In the second embodiment, a member obtained by assembling the center core bodies 42, end-part core bodies 74, and a positioning rod 78 is defined as a stator core.
In the second embodiment, as shown in
In the end-part core body 74, a hole 742 having a shape similar to that of the hole 441 of the first embodiment is formed. The hole 742 is formed to have a so-called taper structure in which the diameter increases from some midpoint. Therefore, the holes in the plate members 741 constructing the end-part core body 74 are formed to have a tapered structure whose diameter varies according to stacking positions.
In the end-part core body 74 of the second embodiment, like in the center core body 42, fitting parts 743 are formed. The fitting parts 743 can be fit in recesses 780 formed at both ends of the positioning rod 78 shown in
Taps 781 are formed in the recesses 780 at both ends of the positioning rod 78. The taps 781 are used for the purposes of fixing of a lead wire and grounding of a wire.
The positioning rod 78 is longer than the positioning rod 48 of the first embodiment. Not only the center core bodies 42 but also the end-part core bodies 74 are fit to the positioning rod 78. Therefore, the housing grooves 51 and 52 in the frame 50 for holding the core assembly 40 have to be also formed long. In the first embodiment, the housing grooves 51 and 52 are formed so as to extend to a position above the step 54 only by the amount of the thickness of the end-part core body 44 (refer to
As described above, in the second embodiment, the end-part core body 74 is also formed by stacking the plate members 741. The plate member 741 can be formed by press work. By forming the end-part core body 74 from the plate members 741, the embodiment is suitable for mass production of the core.
In the second embodiment, the end-part core bodies 74 are also fit to the positioning rod 78. Therefore, the center core bodies 42 and the end-part core bodies 74 can be easily integrated by the positioning rod 78, and positioning can be performed more reliably.
Although the case of forming the taps 781 in the positioning rod 78 and using them for grounding the wire has been described in the embodiment, the invention is not limited to the case. In a manner similar to the first embodiment, taps may be formed in the end-part core body 74 and used to fix the lead wire and to ground the line. In this case, in each of the plate members 741 constructing the end-part core body 74, holes corresponding to the taps 781 are formed.
In the first embodiment, the core assembly 40 is thermal-inserted in the frame 50 to form the stator 30. In a third embodiment, a stator is formed by surrounding the core assembly with a cover in place of the frame 50. The stator of the third embodiment is different from those of the first and second embodiments with respect to the shape but is similar to the first and second embodiments with respect to the function of inserting the movable element 20 and making the movable element 20 move. Therefore, the detailed description of the movable element will not be repeated, and only the configuration of the stator will be described.
As shown in
As shown in
As shown in
After the center core bodies 82 are positioned by the positioning rod 98, end-part core bodies 84 are disposed on the winding coils 46 at both ends. The end-part core bodies 84 on the output side or the opposite side of the movable element are formed in different shapes. However, they will be described using the same reference numeral.
The end-part core body 84 has the hole 842 and a hole 844. The hole 842 is formed in two diameters as shown by an alternate long and short dash line in
Finally, as shown in
The cover 100 is fixed to the core assembly 80 and, in this state, held by a jig. A thermoset resin is poured in the gap and the like between the covers 100 and heated so as to be set, thereby obtaining a stator 110.
As described above, in the third embodiment, only by forming the fitting part 822 having a semicircular shape near the corner of each of the center core bodies 82 and fitting the positioning rod 98 in the fitting part 822, the center core bodies 82 can be easily disposed at predetermined pitches. The fitting part 822 can be easily formed by notching a part in a U shape near a corner of the center core body 82.
Since the fitting part 822 is formed in the corner of the center core body 82, the positioning rod 98 to be fit can be disposed in the open space at the corner of the stator 110. It is unnecessary to specially provide space for the positioning rod 98, so that the size of a motor does not increase.
Since the conductive wires 462 of the winding coils 46 are led in a lump from the hole 844, they can be easily connected to a not-shown power supply. Since the conductive wires 462 are housed in a lump in the open space at the corner of the stator 110, it is unnecessary to specially provide a space for housing the conductive wires 462, so that the size of a motor does not increase.
The first to third embodiments are concrete modes of the present invention. The present invention can be realized in any mode as long as the center core bodies and/or the end-part core bodies are fit at predetermined intervals. Therefore, the invention can be applied not only to the center/end-part core bodies having a circular or square shape as in the first to third embodiments but also to the other shapes.
The entire disclosure of Japanese Patent Application No. 2011-207605 filed on Sep. 22, 2012 including specification, claims, drawings and an abstract are incorporated herein by reference in its entirety.
Number | Date | Country | Kind |
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2011-207605 | Sep 2011 | JP | national |