JPH0759143B2 - Pulse motor - Google Patents

Description

TECHNICAL FIELD The present invention relates to a pulse motor suitable for use in FA (factory automation) equipment that requires relatively large thrust, such as industrial robots. Is.

"Prior Art" As is well known, a linear pulse motor is a stepping motion of a slider or a secondary scale (hereinafter simply referred to as "scale") based on a pulse signal supplied to the slider. The structure of the magnetic circuit is as shown in FIG. In this figure, 1 is a scale composed of a long plate-shaped magnetic body, and the upper surface of the scale is
The uneven tooth portions 1a, 1a, ... Are formed at equal intervals along the longitudinal direction (left-right direction in the drawing). A slider 2 is mounted on the upper surface of the scale 1 in a state in which the slider 2 is movably instructed in the longitudinal direction of the scale 1 by a support mechanism such as a roller (not shown). The slider 2 is a U-shaped A-phase iron core 4
And B-phase iron core 5, coils 6a and 6b wound around A-phase magnetic poles 4a and 4b of A-phase iron core 4, and B-phase magnetic poles 5a and 5b of B-phase iron core 5, respectively. Coils 7a and 7b, permanent magnets 8 and 9 attached to the upper surfaces of the iron cores 4 and 5 with the polarities shown, and the permanent magnet 8
And a back plate 10 made of a plate-shaped magnetic material attached to the upper surfaces of the plates 9 and 9. Then, three pole teeth 14a having the same pitch as the pitch P of the tooth portion 1a of the scale 1 are formed on the lower surface of the magnetic pole 4a.
Similarly, polar teeth 14b, 15a, 15b are formed on the lower surfaces of b, 5a, 5b, respectively. Also, these pole teeth 15b, 14b, 15a are
It is arranged by sequentially shifting by P / 4 with respect to a.
Predetermined gaps G are formed between the lower surfaces of a, 14b, 15a, 15b and the upper surface of the tooth portion 1a. And the coils 6a, 6
By sequentially supplying a predetermined pulse signal to b, 7a, 7b, the magnetic flux generated by the coils 6a, 6b, 7a, 7b and the permanent magnets 8, 9
And the magnetic flux generated by the magnetic poles 4a, 4b, 5a, 5b are sequentially adjusted, and the magnetically stable position of the slider 2 relative to the scale 1 is sequentially moved, whereby the slider 2 is moved along the longitudinal direction of the scale 1. Moving.

Here, a case where the slider 2 is driven by a two-phase excitation method in which current is always supplied to the two sets of coils 6a, 6b and 7a, 7b will be described as an example.

As shown in FIG. 10 (a), terminals 6c to 6 are attached to the coils 6a and 6b.
Apply a predetermined current to d and connect terminals to coils 7a and 7b.
By passing a predetermined current from 7d to 7c, the magnetic flux generated by the coil 6a and the magnetic flux generated by the permanent magnet 8 are added at the A-phase magnetic pole 4a and cancel each other at the phase magnetic pole 4b, while the coil 7a And the magnetic flux generated by the permanent magnet 9 add at the B-phase magnetic pole 5a and cancel each other at the phase magnetic pole 5b, so that the main magnetic flux shown by the solid line φ ₁ in the figure is generated. Phase magnetic pole
The position where the pole teeth 14a and 15a of the B-phase magnetic pole 5a and the tooth portion 1a of the scale 1 vertically face each other is a magnetically stable position.

As shown in FIG. 10 (b), the coils 6a, with flowing a predetermined current to the same direction as in 6b, the coil 7a, by flowing a predetermined current to reverse direction 7b, the solid line in FIG phi ₂ The main magnetic flux indicated by is generated, and as a result, the position where the pole teeth 14a and 15b and the tooth portion 1a face each other becomes a magnetically stable position.

As shown in FIG. 10 (c), the coil 6a, with flow in the reverse direction to the predetermined current and to 6b, the coil 7a, by flowing a predetermined current in the same direction as in 7b, a solid line phi ₃ in FIG. The main magnetic flux shown is generated, which results in each pole tooth 14b and 15b and the tooth
The position where 1a is vertically opposed is a magnetically stable position.

As shown in FIG. 10 (d), the coil 6a, with flow to the predetermined current in the same direction 6b, the coil 7a, by flowing backward to the predetermined current and to 7b, a solid line phi ₄ in FIG. The main magnetic flux shown is generated, which results in each pole tooth 14b and 15a
The position vertically opposed to 1a is a magnetically stable position.

By repeating the pulse excitation in the order of the above →→→ excitation modes, the slider 2 moves in the right direction in the drawing, that is, the direction from the magnetic poles 4a to 5b, and →→
→ By repeating the pulse excitation in the order of each excitation mode, the slider 2 is moved to the left in the drawing, that is, from the magnetic pole 5b.
Move in the direction of 4a. The same applies when the slider 2 is fixed and the scale 1 is moved.

[Problems to be Solved by the Invention] Generally, since a linear pulse motor is capable of high-precision positioning in an open loop, it is used for driving a carriage of a printer of OA (office automation) equipment, etc. Since thrust cannot be obtained, it has been difficult to apply it to FA equipment that requires relatively large thrust, such as industrial robots. That is, in the linear pulse motor described above,
As shown in FIGS. (A) to (d), the magnetic flux generated by the oil 6a or 7a and the magnetic flux generated by the permanent magnets 8 and 9 are added to one of the A-phase magnetic pole 4a or the B-phase magnetic pole 5a, and the thrust force is increased. In the phase magnetic pole 4b or the phase magnetic pole 5b on the other side during the generation, the magnetic flux generated by the coil 6b or 7b and the magnetic flux generated by the permanent magnets 8 and 9 are configured to cancel each other and thrust is not generated. ing. vice versa,
The thrust is not generated in the A-phase magnetic pole 4a or the B-phase magnetic pole 5a while the thrust is generated in the phase magnetic pole 4b or the phase magnetic pole 5b. Therefore, the thrust generation area that actually contributes to the thrust generation is only 50% of the total area of the magnetic poles 4a, 4b, 5a, 5b facing the scale 1, and increasing the thrust generation area will improve the thrust. It was an important issue when trying to Further, in practical application of such a pulse motor with improved thrust, it is also an important issue to have a structure that has a structure as simple as possible, can be easily manufactured, and has sufficient rigidity strength. Was made.

The present invention has been made in view of the above-mentioned circumstances, and the total area of each magnetic pole facing the scale can be effectively used for thrust generation, so that a large thrust can be obtained and a simple configuration can be easily provided. It is an object of the present invention to provide a pulse motor that can be manufactured and has sufficient rigidity strength.

"Means for Solving the Problem" The present invention is directed to a secondary scale having tooth portions at equal intervals along a specific direction, and a primary supported movably in the specific direction with respect to the secondary scale. Side magnetic flux generating section, the primary side magnetic flux is generated by sequentially generating magnetic flux in each gap formed between each magnetic pole of the primary side magnetic flux generating section and each tooth of the secondary side scale. In the pulse motor for moving the part relative to the secondary scale, the secondary scale, a fixed interval P / along the specific direction.
2, a magnetic member in which tooth portions and groove portions are alternately formed, and in each of the groove portions, a permanent magnet respectively inserted and arranged so that polarities of adjacent ones are in mutually opposite directions,
The primary side magnetic flux generating section has N magnetic poles that respectively face the tooth portions of the secondary side scale with a constant gap, and each magnetic pole is displaced by a predetermined dimension P / N in the specific direction. It is characterized in that it is composed of iron cores each having a coil and coils wound around each of the magnetic poles.

[Operation] According to the above configuration, when an electric current is passed through the coil, the magnetic flux flowing from one magnetic pole of the iron core of the primary side magnetic flux generating section to the tooth portion on the S pole side of the secondary side scale passes through the permanent magnet. Since a main magnetic flux loop that flows into the adjacent N-pole tooth portion and flows from the tooth portion to the other magnetic pole of the iron core of the primary-side magnetic flux generation portion, the total of each magnetic pole that faces the secondary-side scale is formed. The area can be effectively used for thrust generation, and a large thrust can be obtained.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing the configuration of a magnetic circuit of a linear pulse motor according to the first embodiment of the present invention.

In this figure, 20 is a fixed scale, and 21 is a slider movably supported in the longitudinal direction of the scale 20 (direction of arrow M in the figure) by a support mechanism such as a roller (not shown).

The scale 20 includes a magnetic member 22 in which tooth portions 22a, 22a, ... And concave grooves 22b, 22b, ... Are alternately formed at a constant interval P / 2 along the longitudinal direction, and the concave grooves 22b. It is composed of permanent magnets 23, 23, ... Which are inserted and arranged so that the polarities of their neighbors are opposite to each other.

On the other hand, the slider 21 is provided with four magnetic poles corresponding to the scale 20 with a constant gap G, that is, an iron core 24 having an A-phase magnetic pole 24A, a phase magnetic pole 24, a B-phase magnetic pole 24B, and a phase magnetic pole 24, respectively. It is composed of coils 25A, 25, 25B, 25 wound around magnetic poles 24A, 24, 24B, 24, respectively. In this case, the relative positional relationship between the magnetic poles 24A, 24, 24B, 24 is as follows. That is, the magnetic pole 24B is (5P
-P / 4) spaced apart, and for each magnetic pole 24A and 24B, each magnetic pole 24 and 24 is each spaced (2P + P / 2) apart, which results in each magnetic pole 24A, 24B, 24, 24 In order,
It is arranged with a displacement of each predetermined dimension P / 4 in the moving direction (direction of arrow M). Also, each magnetic pole 24A, 24, 24B, 2
The end face of the scale 21 facing the scale 21 has pole teeth 24Aa, 24Ab, 24 having substantially the same facing area as the tooth portion 22a of the scale 21.
a, 24b, 24Ba, 24Bb, 24a, 24b are formed respectively.

In the above configuration, in the state where no current is supplied to each coil 25A, 25, 25B, 25, as shown by the dotted arrow in FIG. 2, from the N pole of each permanent magnet 23, 23, ... A magnetic flux loop that returns to the position is formed, and as shown by the solid line arrow in FIG.
from a into each magnetic pole 24A, 24, 24B, 24 of the slider 21,
A magnetic flux loop that returns to the tooth portion 22a on the S pole side of the scale 20 is formed again, and is stationary in this state.

Here, FIG. 3 shows the operation when the slider 21 is driven by the one-phase excitation method in which a current is supplied to one of the set of the A phase and the phase coils 25A, 25 or the set of the B phase and the phase coils 25B, 25. It will be described with reference to FIG.

In the state shown in FIG. 3 (a), the A phase and the phase coil
When a predetermined current is applied to 25A and 25 in the direction from the X mark to the A mark shown in the figure, the iron core 24 moves from the phase magnetic pole 24 to the A phase magnetic pole.
A magnetomotive force is generated by the coils 25A, 25 toward 24A, which causes the A-phase magnetic pole 24A of the iron core 24 as shown by φ ₁ in the figure.
The magnetic flux flowing from each pole tooth 24Aa, 24Ab into the S pole side tooth portion 22a of the scale 20 flows into the adjacent N pole side tooth portion 22a via the permanent magnet 23, and from this tooth portion 22a the iron core 24a The phase pole 24
A main magnetic flux loop flowing into each pole tooth 24a, 24b is formed. As a result, the pole teeth 24Aa, 24Aa of the A-phase magnetic pole 24A face the tooth portion 22a of the scale 20 on the S pole side, and the pole teeth 24a, 24b of the phase magnetic pole 24 are tooth portion 22a on the N pole side of the scale 20. The position opposed to is a magnetically stable position.

As shown in FIG. 3 (b), the B phase and the phase coils 25B, 25
On the other hand, when a predetermined current is applied in the direction from the mark x to the mark shown in the figure, a main magnetic flux loop indicated by φ ₂ is generated in the figure, and as a result, each pole tooth 24Ba of the B-phase magnetic pole 24B, 24, 24 Bb scale 20
Facing the S pole side tooth portion 22a of each of the pole teeth 24 of the phase magnetic pole 24
The positions where a and 24b face the teeth 22a on the N pole side of the scale 20 are magnetically stable positions.

As shown in FIG. 3 (c), the A phase and the phase coils 25A, 25
When a predetermined current is applied in the direction opposite to, a main magnetic flux loop indicated by φ ₃ in the figure is generated, and as a result, each pole tooth 2 of the A-phase magnetic pole 24A
4Aa and 24Ab face the tooth portion 22a on the N pole side of the scale 20,
The position where the pole teeth 24a and 24b of the phase magnetic pole 24 face the S-pole side tooth portion 22a of the scale 20 is a magnetically stable position.

As shown in Fig. 3 (d), the B phase and the phase coils 25B, 25
When a predetermined current flows in the direction opposite to, a main magnetic flux loop indicated by φ ₄ in the figure is generated, and as a result, each pole tooth of the B-phase magnetic pole 24B 2
4Ba, 24Bb face the tooth portion 22a on the N pole side of the scale 20,
The position where each pole tooth 24a, 24b of the phase magnetic pole 24 faces the tooth portion 22a on the S pole side of the scale 20 is a magnetically stable position.

By repeating pulse excitation in the order of →→→ above, slider 21 moves to the right in the drawing, and by repeating pulse excitation in the order of →→→ each excitation mode, slider 21 moves to the left in the drawing. Move to.

Next, a three-phase linear pulse motor according to a second embodiment of the present invention will be described with reference to FIG. In the figure, reference numeral 42 denotes a slider movably supported in the longitudinal direction of the scale 21 (direction of arrow M in the figure) by a supporting mechanism such as a roller (not shown). The slider 42 has an A-phase magnetic pole 43A.
And an iron core 43 having a B-phase magnetic pole 43B and a C-phase magnetic pole 43C,
It is composed of coils 44A to 44C wound around the magnetic poles 43A to 43C, respectively. In this case, the magnetic pole 43 located on one side
A, magnetic pole 43B located in the center, magnetic pole 43C located on the other side
In this order, the scale 20 is sequentially displaced by P / 3 in the longitudinal direction (M direction) of the scale 20, so that the B-phase magnetic pole 43B in the state where the A-phase magnetic pole 43A faces the tooth portion 22a of the scale 20. Is displaced from the tooth portion 22a by 1/3 of P, and the C-phase magnetic pole 43C is displaced from the tooth portion 22a by 2/3 of P.

In the above configuration, the A phase coil 44A, the B phase coil 44B, and the C phase coil are arranged in the excitation sequence as shown in FIG.
The operation when so-called bipolar driving is performed by supplying a pulse current whose polarity is inverted to 44C will be described.

First, FIG. 6 is a diagram showing thrust vectors generated between the magnetic poles 43A to 43C of the slider 42 and the tooth portions 22a of the scale 20. In this figure, A indicates a thrust vector generated when a drive current is supplied to the A-phase coil 44A in the positive direction, and A indicates a thrust vector generated when a drive current is supplied to the A-phase coil 44A in the negative direction. , B and C
Indicates thrust vectors generated when a drive current is supplied to the B-phase coil 44B and the C-phase coil 44C in the positive direction,
And indicate the thrust vectors respectively generated when the drive current is supplied to the B-phase coil 44B and the C-phase coil 44C in the negative direction.

Then, in the period shown in FIG.
Drive current is supplied to 44A in the positive direction, and phase B coils 44B and C
A drive current is supplied to the phase coil 44C in the negative direction,
As shown in FIG. 6, the vector A, the vector, and the combined vector become the thrust vector,
It acts between the scale 22 and the slider 42. Then →
→… → When a drive current is supplied to the coils 44A to 44C in the order shown, the magnetic poles 43A to 43C of the slider 42 and the scale 20 are fed.
6, the thrust vector generated between each tooth portion 22a of the slider 42 changes in the order shown by →→ ... → in FIG. 6, and the magnetic stable point of the slider 42 relative to the scale 20 changes. In this way, →→→… → in the order of each excitation mode, or →
The slider 42 is moved by repeating the pulse excitation in the order of →→→→.

Next, the configuration of the third embodiment of the present invention, which is applied to a disk / rotor type / double-sided drive type pulse motor, will be described with reference to FIGS. In these figures, 50 is a housing, and 51 is a shaft rotatably supported by the housing 50 via bearings 52 and 53. A disk-shaped rotor 54 is fixed to the shaft 51 by a key 55, and annular stators 56 and 57 that face both surfaces of the rotor 54 with predetermined gaps are provided in the housing 50. Each is installed. The rotor 54 is arranged between annular members 59 and 60 made of a non-magnetic material, and between these members 59 and 60, and has tooth portions 61a, 61a, ... And concave grooves 61b, 61b ,. Disc-shaped magnetic member 61 in which the grooves are formed, and the respective concave grooves 61b, 61b, ...
In addition, the permanent magnets 62, 62, ... Which are inserted and arranged so that the magnets adjacent to each other are in opposite directions to each other. Further, the stator 56 includes the magnetic poles 24A, shown in FIG.
Magnetic poles 65a to 65d having the same positional relationship as 24, 24B, 24
And the coils 66a to 66d wound around these magnetic poles 65a to 65d, respectively, and the stator 57 is also configured in the same manner. In the above structure, the rotor 54 is rotationally driven according to the same operation principle as that of FIG. 3, and the shaft 51 is rotated.

Next, the configuration in the case of being applied to the outer rotor type pulse motor according to the fourth embodiment of the present invention will be described with reference to FIG. In this figure, 70 is a cylindrical outer rotor, which has tooth portions 71a, 71a, ...
, And the magnetic member 71 in which the concave grooves 71b, 71b, ... Are alternately formed, and the permanent magnets inserted and arranged in the concave grooves 71b, 71b ,. 72,72, ...
It consists of and. The stator 74 includes an A-phase magnetic pole 75A, a B-phase magnetic pole 75B, a C-phase magnetic pole 75C, and a phase magnetic pole 75, which have the same positional relationship as the magnetic poles 43A, 43B, 43C shown in FIG.
The phase magnetic pole 75, an iron core 75 having the phase magnetic pole 75 formed thereon, and coils 76A to 76 wound around these magnetic poles 75A to 75, respectively, are fixed to a shaft 78. In the above structure, the outer rotor 70 is rotationally driven according to the same operation principle as that of the embodiment shown in FIG.

The present invention is not limited to the above-described embodiments, and various modifications described below are possible.

The primary slider may be provided with a sensor that detects the amount of relative movement with respect to the secondary scale, and may be driven as a servo motor.

A skew structure or a slight pitch shift (equivalent skew) within the same pole may be applied in order to remove cogging or improve thrust waveform distortion.

[Advantages of the Invention] As described above, according to the present invention, the secondary scale includes a magnetic member in which teeth and grooves are alternately formed at a constant interval P / 2 along a specific direction, and each groove. , And the permanent magnets that are inserted and arranged so that the polarities of their neighbors are opposite to each other, the primary side magnetic flux generator is separated from each tooth of the secondary side by a certain gap. Each of the magnetic poles has N magnetic poles facing each other, each magnetic pole is arranged with a displacement of a predetermined dimension P / N in a specific direction, and an iron core is wound around each magnetic pole. When a current is passed through the coil of No. 1, the magnetic flux flowing from one magnetic pole of the iron core of the primary side magnetic flux generating section to the tooth section on the S pole side of the secondary side scale is placed on the adjacent N pole side via the permanent magnet. The main magnet that flows into the teeth and flows from the teeth to the other magnetic pole of the iron core of the primary side magnetic flux generator. Since the bundle loop is formed, the total area of each magnetic pole facing the secondary scale can be effectively used for thrust generation, and a thrust twice that of the conventional one can be obtained. The effect is that it can be applied to FA devices such as robots that require relatively large thrust.

[Brief description of drawings]

FIG. 1 is a front view showing a magnetic circuit configuration of a linear pulse motor according to a first embodiment of the present invention, FIG. 2 is a front view for explaining a magnetic flux path of the same embodiment at rest, and FIG. ) To (d) are front views for explaining the operation when the same embodiment is driven by the one-phase excitation method, and FIG. 4 shows the magnetic circuit configuration of the multi-phase linear pulse motor according to the second embodiment of the present invention. FIG. 5 is a perspective view showing the excitation sequence in the linear pulse motor, FIG. 6 is a diagram explaining the thrust vector in each excitation mode of the linear pulse motor, and FIG. 7 (a). Is a partial cross-sectional view showing the configuration of a disk rotor type pulse motor according to a third embodiment of the present invention, FIG. 6B is a partial front view showing the configuration of the stator side of the pulse motor, and FIG. Pulse motor disc FIG. 8 is a partial sectional view showing the structure of the rotor, FIG. 9D is a partial front view showing the structure of the disk rotor of the pulse motor, and FIG. 8 is the inside of the outer rotor type pulse motor according to the fourth embodiment of the present invention. FIG. 9 is a front view showing the configuration, FIG. 9 is a diagram showing a magnetic circuit configuration of a conventional linear pulse motor, and FIGS. 10 (a) to 10 (d) are operations when the linear pulse motor is driven by a two-phase excitation method. It is a figure for explaining. 20 …… Scale (secondary side scale), 21 …… Slider (primary side magnetic flux generating part), 22 …… Magnetic member, 22a …… Tooth, 22b …… Concave groove (groove), 23 …… Permanent magnet, 24 …… Iron core, 24A …… A phase magnetic pole, 25A …… A phase coil, 24 …… Phase magnetic pole, 25 …… Phase coil, 24B …… B phase magnetic pole, 25B …… B phase coil, 24 …… Phase magnetic pole , 25 …… Phase coil.

Claims (2)

[Claims] 1. A secondary-side scale having teeth at equal intervals along a specific direction, and a primary-side magnetic flux generator movably supported in the specific direction with respect to the secondary-side scale, By sequentially generating magnetic flux in each gap formed between each magnetic pole of the primary side magnetic flux generating section and each tooth section of the secondary side scale, the primary side magnetic flux generating section with respect to the secondary side scale. In the pulse motor that relatively moves the secondary scale, the secondary scale is spaced at regular intervals along the specific direction.
A magnetic member in which tooth portions and groove portions are alternately formed at P / 2, and a permanent magnet that is inserted and arranged in each groove portion such that polarities of adjacent ones are opposite to each other, The primary side magnetic flux generating section has N magnetic poles that respectively face the tooth portions of the secondary side scale with a constant gap, and each magnetic pole is displaced by a predetermined dimension P / N in the specific direction. And a coil wound around each of the magnetic poles, and a pulse motor. 2. The tooth portion and the groove portion are formed on both surfaces of the secondary side scale, and a permanent magnet is inserted and arranged in each of the groove portions, while facing the tooth portions on both surfaces of the secondary side scale. A pair of primary side magnetic flux generating sections are provided, and these primary side magnetic flux generating sections are connected to each other and are supported so as to be movable relative to the secondary side scale in the specific direction. The pulse motor according to claim 1.