JPH03218251A - Dc brushless linear motor - Google Patents

Abstract

PURPOSE:To avoid the unevenness of a speed and an eddy current by a method wherein a magnetic pole row and a magnetic element are fixed to a base in parallel with each other with a predetermined distance and a movable coil fixed to a movable table is provided between the magnetic pole row and the magnetic element. CONSTITUTION:If a current is applied to a movable coil 69, a thrust force is generated by Fleming's left-hand law in a longitudinal direction of a base 1 in accordance with the direction of the current and a movable table 6 starts moving by the thrust force. At that time, as vertical direction flux crossing the movable coil 69 is formed between a magnetic pole row 3 and a magnetic element 16 which are both fixed to the base 1, the vertical direction flux does not fluctuate by the movement of the movable table 6 and the uniform state of the flux is maintained. With this constitution, as the flux which crosses the respective movable coils 69 are not varied, the variation of the thrust force is not created, so that the variation of a speed can be avoided.

Description

[Detailed Description of the Invention] [Field of Application in Industry] This invention relates to a DC brushless linear motor that travels relatively short distances, such as a carrier for semiconductor manufacturing or a linear motion scanner for an analyzer. The present invention relates to a DC brushless linear motor that can ensure stable running by generating magnetic flux uniformly over the entire running range from a borosilicate pole array of a base serving as a stator.

[Conventional technology]

2. Description of the Related Art As a conventional DC brushless linear motor, for example, one having a configuration shown in FIGS. 3 and 4 is known.

This conventional example consists of a base 1 made of a magnetic material with a rectangular cross section and a predetermined length, and permanent magnets 2 formed on one surface of the base 1 that are magnetized with opposite polarities in the longitudinal direction and arranged alternately to form N poles. and T11. in which the S poles are aligned alternately. A movable table 6 is arranged on the base 1 so as to be slidable in the longitudinal direction via a guiding rolling bearing 4.5, and a movable table 6 is fixed to the lower surface of the movable table 6 facing the magnetic pole row 3. It is composed of a magnetic body 7 serving as a magnetic yoke, and a plurality of moving coils 8 wound around the lower surface of the magnetic body 7.

By controlling the energization of the movable coil 8, a propulsive force is generated according to Fleming's left-hand rule, and the movable table 6 is reciprocated along the base 1.

[Problems to be Solved by the Invention] However, in the above-mentioned conventional DC brushless linear motor, the magnetic flux generated from the N pole of the magnetic pole array 3 formed on the base 1 is transmitted through the magnetic body 7 of the movable table 6. A magnetic circuit that reaches the south pole is constructed, and the propulsion force is obtained by controlling the energization of the movable coil existing within the magnetic flux.
When is stopped, as shown in Fig. 4(a),
The movable coil 8 is formed uniformly in the perpendicular direction over the entire surface of the magnetic body 7 around which the movable coil 8 is wound. However, when the movable table 3 starts moving, the magnetic material 7 is disposed from the magnetic pole array 3 as shown in FIG. 4(b). The magnetic flux toward the magnetic body 7 and the magnetic flux conversely from the magnetic body 7 toward the magnetic pole array 3 both change from the vertical direction to the oblique direction as the magnetic body 7 moves, and the magnetic flux flows toward the magnetic yoke around which the moving coil 8 is wound. It becomes impossible to obtain a uniform magnetic flux in the vertical direction, resulting in uneven magnetic flux, and as a result, the moving coil 8
There have been unresolved problems in that the propulsion force is uneven, which tends to cause speed unevenness, and eddy currents are generated, leading to a decrease in the propulsion force.

3 In addition, since iron is generally used as the magnetic material 7, the weight becomes relatively large, the mass of the entire movable table 6 increases, the inertial force increases, the response decreases, and the work that can be extracted externally of the motor increases. There was also an unresolved issue of smaller volumes.

Therefore, this invention was made by focusing on the unresolved problems of the above-mentioned conventional example, and it is possible to uniformly form magnetic flux perpendicular to the movable coil regardless of the movement of the movable table, and to improve speed. The purpose of the present invention is to provide a DC brushless linear motor that can prevent the occurrence of unevenness and eddy currents, reduce the mass of the entire movable table, improve responsiveness, and increase the amount of external work. It is said that

[Means to solve the problem]

In order to achieve the above object, the DC brushless linear motor according to the present invention has a movable table slidably mounted on a base made of a magnetic material forming a magnetic pole row in which N poles and S poles are arranged alternately in the longitudinal direction. A DC brushless linear motor is provided with a movable l coil on a surface of the movable table facing the magnetic pole array, wherein a magnetic body is disposed on the base and faces the magnetic pole array at a predetermined distance; A movable coil fixed to the movable table is interposed between the magnetic body and the magnetic pole array.

[Effect]

In this invention, a base serving as a stator is provided with a magnetic pole array and a magnetic body facing the magnetic pole array with a predetermined interval, and a movable table fixed to a movable table is provided between the magnetic pole array and the magnetic body. Because the coil is arranged, vertical magnetic flux can always be uniformly formed between the magnetic pole array fixed to the base and the magnetic body regardless of the movement of the movable table, and speed irregularities due to uneven propulsion force can occur. In addition, it is possible to prevent the occurrence of eddy currents, and
Since there is no need to provide a magnetic body on the movable table, the mass of the movable table as a whole can be reduced, responsiveness can be improved, and the amount of external work can be increased to improve efficiency.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a front view showing an embodiment of the present invention, and FIG. 2 is a sectional view taken along the line A--A in FIG. 1.

In the figure, reference numeral 1 denotes a base made of a magnetic material with a rectangular cross section and a predetermined length, and on its upper surface, square plate-shaped permanent magnets 2 magnetized with reverse polarity are arranged alternately in the longitudinal direction of the base 1. A magnetic pole row 3 is formed in which north poles and south poles are arranged alternately. Also, on the left end side of base 1, base 1
A supporting plate 11 made of a non-magnetic material extending in the longitudinal direction is fixed by, for example, screws 12, and a magnetic material 13 extending parallel to the magnetic pole array 3 is attached to the upper surface of the supporting plate 11 by screws 13.
It is fixed by a. This magnetic body 13 is connected to a mounting plate portion 14 attached to the support plate 11 and a mounting plate portion 14 attached to the support plate 11.
A horizontal plate part 16 is integrally connected to the right end side of the magnetic pole array via a step part l5, and the horizontal plate part l6 faces the magnetic pole array 3 with a predetermined distance therebetween.

Furthermore, a movable table 6 is slidably disposed on the upper surface of the base 1. The movable table 6 is formed into an L-shaped cross section, including a horizontal plate part 61 facing the base 1 and a vertical plate part 62 extending downward from the right end of the horizontal plate part 61. A guide roller 64 made of, for example, a rolling bearing is pivotally attached to a support piece 63 formed at the center of the lower surface, and a similar guide roller 65 is attached to the lower end of the vertical plate part 62, and a horizontal plate Part 6
Similar guide rollers 66 and 67 are pivotally mounted on the left end position of the base 1 and on the left side of the guide roller 64, respectively. Guide rollers 66 and 67 are in rolling contact with the right end edge, and guide rollers 66 and 67 are in rolling contact with the left and right ends of the mounting plate portion l4, respectively, so that the movable table 6 can freely slide in the longitudinal direction of the base 1. Further, a coil case 68 made of a non-magnetic material extending between the magnetic pole array 3 and the magnetic body 13 is screwed at a position corresponding to the space between the magnetic pole array 3 and the magnetic body 13 on the left end surface of the vertical plate portion 62 of the movable table 6. 7, and a plurality of movable coils 69 are wound around the coil case 68 at positions facing the magnetic pole array 3 and the magnetic body 13 in a continuous manner in the longitudinal direction of the base 1.

Next, the operation of the above embodiment will be explained. Now moving coil 6
In a stopped state where power is not applied to the stator 9, the magnetic flux generated from the N pole of the magnetic pole array 3 fixed to the base 1 serving as a stator is directed toward the horizontal plate portion 16 of the magnetic body 13 fixed to the base 1. , a magnetic circuit is constructed by moving from a position of this horizontal plate portion 16 facing the S pole of the magnetic pole array 3 toward the S pole, and between the magnetic pole array 3 and the magnetic body 13, the N pole position of the magnetic pole array 3 and the N pole position of the magnetic pole array 3 are formed. A uniform magnetic flux in the vertical direction is formed in the opposite direction to the S pole position. At this time, since the movable coil 69 is in a non-energized state, no propulsive force is generated in the longitudinal direction of the base, and the stopped state continues.

By energizing the movable coil 69 from this state, a propulsive force is generated on either side in the longitudinal direction of the base according to Fleming's left hand rule depending on the direction of energization, and the movable table 6 begins to move. do. At this time, since the vertical magnetic flux that crosses the movable coil 69 is formed between the magnetic pole array 3 and the magnetic body 13, both of which are fixed to the base 1, the vertical magnetic flux is also fluctuated by the movement of the movable table 13. It maintains a uniform state without becoming overcooked.

Therefore, since the magnetic flux crossing each moving coil 69 does not change, there is no uneven propulsion force, no uneven speed, and it is possible to prevent the generation of eddy currents and suppress heat generation. can. Furthermore, since the movable table 6 does not require a magnetic body as the magnetic yoke of the movable coil 69, the mass of the movable table 6 as a whole can be reduced accordingly, and the inertia of the movable table can be reduced. The responsiveness when controlling the movement of the movable table 6 can be improved, and the amount of work that can be taken out to the outside can be increased to improve efficiency.

Further, after stopping the energization to the movable coil 13 and stopping the movable table 6, the polarity of the current supplied to the movable coil 13 is reversed to cause the movable table 6 to travel in the opposite direction to that described above. be able to.

In the above embodiment, a case has been described in which the magnetic pole array 3 is disposed on the upper surface of the base 1 and the magnetic body 13 is disposed at a predetermined distance from the magnetic pole array 3, but the present invention is not limited to this. , the magnetic pole array 3 and the magnetic body 13 can also be arranged in an upside-down relationship.

Further, in the above embodiment, a case has been described in which the movable table 6 is slidably disposed on the base 1 using guide rollers 64 to 67, but the present invention is not limited to this. It is also possible to apply a linear guide composed of a slider that is guided through an intervening slider.

〔Effect of the invention〕

As explained above, according to the present invention, a magnetic pole array and a magnetic body are fixed to the base in parallel with a predetermined interval, and a movable coil fixed to a movable table is interposed between the magnetic pole array and the magnetic body. With this configuration, a stable vertical magnetic flux can always be formed between the magnetic pole array and the magnetic body regardless of the movement of the movable table, and the generation of uneven propulsive force due to the movable coil can be suppressed, which is superior to the conventional example. It is possible to improve the propulsion force by about 20%, and
It is possible to reduce the speed unevenness of the movable table and improve the motion accuracy, and it is also possible to prevent the generation of eddy currents, so it is possible to suppress heat generation, and there is no need to provide a magnetic material on the movable table. As a result, the mass of the entire movable table can be reduced and the inertia force can be reduced, resulting in improved responsiveness and the amount of work that can be taken out to the outside, making it highly efficient. Moreover, effects such as being able to obtain high propulsive force can be obtained.

[Brief explanation of drawings]

Fig. 1 is a front view showing one embodiment of the present invention, Fig. 2 is a sectional view taken along the line A-A in Fig. 1, Fig. 3 is a front view of a conventional example, and Fig. 4 is a front view showing an embodiment of the present invention.
Figures (a) and (b) are the third example used to explain the operation of the conventional example.
It is a sectional view taken along the line BB in the figure. In the figure, 1 is a base, 2 is a permanent magnet, 3 is a magnetic pole array, 6 is a movable table, 13 is a magnetic body, 64 to 67 are guide rollers, and 69 is a movable coil.

Claims (1)

[Claims] A movable table is slidably disposed on a base made of a magnetic material and has a magnetic pole array in which N poles and S poles are arranged alternately in the longitudinal direction, and a movable coil is provided on a surface of the movable table facing the magnetic pole array. In the installed DC brushless linear motor,
A DC brushless, characterized in that a magnetic body facing the magnetic pole array at a predetermined interval is disposed on the base, and a movable coil fixed to the movable table is interposed between the magnetic body and the magnetic pole array. linear motor.