JPH11146625A - Torque motor - Google Patents

Abstract

(57) [Problem] To provide a torque motor capable of generating stable torque without generating torque ripple. SOLUTION: A plurality of plate magnets 43a and 44 of the same size are provided.
a are arranged at symmetrical positions on the outer periphery of the rotor core 42. One flat magnet 43a or 44a is
Assuming that the angle occupied in the circumferential direction on the outer periphery of the two is A, the two slot connecting portions 48 and 49 between the stators 45 and 46
Is 1 of the angle A from the opposite side of the rotor 41 by 180 ° in the circumferential direction.
/ 2 position. The solenoids 50 and 55 are at an angle of 1/2 A
It is arranged at a position shifted only by facing the slot connecting portions 48 and 49. Thereby, the slot connecting portions 48, 4
The torque ripples generated in the vicinity of 9 cancel each other, and a stable torque is generated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a torque motor, and more particularly, to a torque motor used for a flow control valve or the like.

[0002]

2. Description of the Related Art Conventionally, as disclosed in JP-A-3-31529 and JP-A-6-253516, a torque motor using an arc-shaped magnet has been known. These are used as actuators of a valve device such as an intake flow control valve of an internal combustion engine.

[0003]

However, the production of an arc-shaped magnet usually requires a cutting step, which requires a lot of work, and is costly because there are many wasteful materials. Therefore, it is conceivable to arrange a plurality of plate magnets in close contact with each other and arrange them on the outer periphery of the rotor core, or to arrange a plurality of magnets at intervals to form a rotor having two poles as a whole.

However, when a plurality of magnets are arranged as described above, the magnetic force decreases between the magnets. Even when the magnets are arranged in close contact with each other, the magnetic force between the magnets decreases due to the difference in the magnetization direction.
Furthermore, when a flat magnet is used as the magnet, the gap between the magnet and the inner wall of the stator fluctuates in the circumferential direction, and the generated magnetic force fluctuates. For these reasons, there is a problem that a torque ripple, in which the torque generated by the torque motor periodically fluctuates depending on the rotation angle of the rotor, is generated and stable torque cannot be obtained, so that precise control is difficult.

The present invention has been made to solve such a problem, and an object of the present invention is to provide a torque motor which does not generate torque ripple and can generate a stable torque.

[0006]

According to the first aspect of the present invention, when the leading edge of one magnetic pole of the stator corresponds to the edge of the magnet of one magnetic pole of the rotor, the torque of the stator is reduced. Since the leading edge of the other magnetic pole is arranged so as to correspond substantially to the center of the magnet of the other magnetic pole of the rotor, the periodic torque generated when the magnetic pole of the rotor is formed by a magnet group in which a plurality of magnets are arranged. The fluctuation is canceled, and the magnitude of the torque according to the rotation angle of the rotor in the predetermined range can be made substantially constant. Therefore, it becomes easy to precisely control the rotation angle of the torque motor. For example, it is suitable when a plurality of flat magnets are used as the magnets provided on the rotor or when a plurality of magnets are arranged at intervals in the rotor core.

According to the torque motor according to the second aspect of the present invention, since the magnet provided on the rotor has a flat plate shape, the cost of manufacturing the magnet can be reduced as compared with the case where an arc-shaped magnet is used. .

When the leading edge of one pole of the stator corresponds to the edge of the magnet of one pole of the rotor, the leading edge of the other pole of the stator corresponds to substantially the center of the other pole of the rotor. For example, a method of shifting the arrangement angle of the pair of magnets on the rotor with respect to the rotation axis and the arrangement angle of the front edge of the pair of magnetic poles on the stator by half of the magnet pitch on the rotor. Can be adopted. For example, the arrangement angle of the pair of magnetic poles on the rotor with respect to the rotation axis is set to 180 ° so that the arrangement of the front edge of the pair of magnetic poles on the stator side is asymmetric, and the arrangement of the front edge of the pair of magnetic poles on the stator side is the rotation axis. Means that the arrangement of the two magnet groups forming the pair of magnetic poles on the rotor side is an asymmetrical position, or the arrangement of the leading edge of the pair of magnetic poles on the stator side and the two magnet groups on the rotor side Means for making both of these arrangements asymmetric can be adopted.

The edge of the magnetic pole of the stator can be defined as a boundary with a pair of magnetic poles in a slotless structure to be described later, or as an edge of a range that functions as a substantial magnetic pole, and has a slot. In construction, it can be defined as the structural edge of the pole facing the slot.

According to the torque motor of the third aspect of the present invention, the substantially center of the magnet is a position within 1/12 of the magnet pitch from the position where the magnet is bisected in the circumferential direction. Therefore, it is possible to minimize the fluctuation of torque due to the rotation angle of the rotor while allowing manufacturing tolerances to facilitate the assembly operation.

[0011]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a first embodiment of the present invention; (First Embodiment) FIGS. 1 and 2 show a throttle valve control apparatus using a torque motor according to a first embodiment of the present invention. The throttle valve control device 10 shown in FIG. 2 has no mechanism mechanically linked to the accelerator for adjusting the opening of the throttle valve 13 according to the accelerator pedal depression amount, and the opening of the throttle valve 13 is controlled only by the torque motor 40. Is to adjust.

A throttle body 11 of the throttle valve control device 10 rotatably supports a throttle shaft 12 via bearings 15 and 16. Throttle valve 13
Is formed in a disk shape, and a screw 1 is
It is fixed at 4. When the throttle valve 13 rotates together with the throttle shaft 12, the throttle body 1
The flow passage area of the intake passage 11a formed by the inner wall of the first intake passage 11 is adjusted, and the flow rate of intake air passing through the intake passage 11a is controlled.

A throttle lever 21 is press-fitted and fixed to one end of the throttle shaft 12, and the throttle lever 21 rotates together with the throttle shaft 12. The stopper screw 22 abuts on the throttle lever 21 to define the fully closed position of the throttle valve 13. By changing the screwing amount of the stopper screw 22, the fully closed position of the throttle valve 13 can be adjusted.

The rotation angle sensor 30 includes a throttle lever 2
1, a contact portion 31, a substrate 32 coated with a resistor, and a housing 33. Contact part 3
1 is press-fitted into the throttle shaft 12 and rotates together with the throttle shaft 12. The substrate 32 is fixed to the housing 33, and the contact portion 31 slides on the resistor applied to the substrate 32. A constant voltage of 5 V is applied to the resistor applied to the substrate 32, and when the sliding position between the resistor and the contact portion 31 changes according to the opening of the throttle valve 13, the output voltage value changes. An electronic control unit (ECU) (not shown) receives the output voltage value from the rotation angle sensor 30 and detects the opening of the throttle valve 13.

At the other end of the throttle shaft 12, FIG.
As shown in the figure, the rotor 41, the cores 45 and 46, and the pair of solenoids 50 and 55 constitute the torque motor 40. The end of the torque motor 40 is covered by the cover 20. The rotation direction of the rotor 41 is the clockwise direction shown in FIG.

The rotor 41 is composed of a rotor core 42 as a rotor body press-fitted and fixed to the throttle shaft 12, and magnet groups 43 and 44 provided on the outer periphery of the rotor core 42 on the radially opposite side. The magnet groups 43 and 44 include a plurality of plate magnets 43a and 44a having the same size, respectively.
2 adhered to the outer periphery. These plate magnets 43a, 44
Each of a is arranged closely in the circumferential direction in the magnet group. Plate magnet 43a and magnet group 44 of magnet group 43
44a are provided symmetrically on the opposite side of the outer circumference of the rotor core 42 by 180 °.

Each of the plate magnets 43a and 44a is magnetized in the radial direction of the rotor 41, and one of the magnet groups 43 and 44 has an N pole on the outside in the radial direction and the other has an S pole. Thereby, one side of the plane parallel to the rotation axis of the rotor 41 can be an N pole and the other side can be an S pole. As the plate magnets 43a and 44a, it is desirable to use a so-called rare earth permanent magnet that generates a high magnetic force, such as a neodymium-based or samarium-cobalt-based magnet, but other permanent magnets such as a ferrite-based magnet can also be used.

The stator includes cores 45 and 46 and solenoids 50 and 55. An accommodation hole 47 for accommodating the rotor 41 is formed by the cores 45 and 46. Core 4
5 and 46 form a pair of magnetic poles facing the accommodation hole 47. The solenoids 50,
55 are connected, and the core 4 is
5, 46 are excited.

The cores 45 and 46 are formed by laminating thin magnetic steel plates in the axial direction of the throttle shaft 12.
Are arranged and fixed so as to face each other. These cores 45 and 46 are closely butted by slot connecting portions 48 and 49. Therefore, the cores 45, 46
Has a slotless structure having substantially no slots when viewed from the rotor.

The slot connecting portions 48 and 49 are formed thin so as to sufficiently reduce the cross-sectional area as a magnetic flux passage. The slot connecting portions 48 and 49 define a boundary between a pair of magnetic poles formed by the stator.
These slot connecting portions 48 and 49 are arranged at asymmetric positions when viewed from the rotor 41. Assuming that the arrangement pitch angle of the plate magnets 43a and 44a on the rotor 41 is A, the slot connecting portions 48 and 49 are shifted from the symmetrical position on the opposite side by 180 ° by a half (1/2) of the magnet pitch angle A. positioned. Thereby, a pair of magnetic poles on the rotor,
The pair of magnetic poles on the stator is arranged so as to be shifted by half the magnet pitch on the rotor.

The solenoid portions 50 and 55 are formed by winding coils 52 and 57 around iron cores 51 and 56, respectively, and cores 45 and 46 sandwich the rotor 41 therebetween.
Is fixed between. The solenoids 50 and 55 are arranged opposite to the slot connecting parts 48 and 49 at a position shifted from the opposite side of the rotor 41 by 180 ° in the circumferential direction by の of the angle A. When the coils 52 and 57 are energized, two poles of an N pole are generated on one of the cores 45 and 46 of the stator, and an S pole is generated on the other. A torque for rotating the rotor 41 is generated by the magnetic poles on the rotor 41 side generated by the magnet groups 43 and 44 and the magnetic poles on the stator side generated by energization. The return spring 17 has one end fixed to the rotor core 42 and the other end fixed to the screw 18, and biases the throttle valve 13 in the closing direction.

FIG. 3 is a schematic diagram for explaining the relationship between the positions of the magnetic poles on the stator side and the positions of the plate magnets generated in the torque motor having the structure shown in FIG. The plurality of plate magnets are respectively symmetrically arranged on both sides in the circumferential direction of the rotor, and the N and S poles of the stator are formed so as to surround the rotor. In the north pole and the south pole of the stator, the edge on the side where the magnet comes due to the rotation of the rotor is called the front edge or front edge of the magnetic pole. Since the position of the front edge of the N pole and the front edge of the S pole are shifted from the symmetric position by half of the magnitude of the magnet pitch, one of the magnetic poles of the stator (S pole in this case) is used.
Correspond to the edge of the rotor magnet pitch, the front edge of the other pole of the stator (here the north pole) corresponds to approximately the center of the magnet pitch.

FIG. 13 shows a comparative example. The substantially same parts as those in the first embodiment shown in FIG. In the comparative example, the same number of the plate magnets 43a and 44a are provided symmetrically on the opposite side of the outer periphery of the rotor core 42 by 180 ° similarly to the first embodiment. The cores 453 and 463 are provided substantially symmetrically, and the two slot connecting portions 483 and 49 are provided.
Reference numeral 3 denotes a position 180 ° opposite to the rotor 41.

FIGS. 5 and 6 are characteristic diagrams showing the relationship between the rotation angle and the magnitude of the generated torque by the torque motors of the comparative example and the first embodiment. The torque generated by the torque motor of the comparative example is the same as that of the slot connecting portion 483 in FIG.
This is a combination of two torques that are generated most strongly in the X and Y sections near 493. The plate magnets 43a and 44a are located at symmetrical positions on the outer periphery of the rotor core 42, and the slot connecting portions 483 and 493 are also located at symmetrical positions across the rotor 41. Therefore, with the rotation of the rotor, the edge of the magnet is simultaneously applied to the X portion and the Y portion, which are the edges of both magnetic poles, and the central portion of the magnet is also at the same time. Therefore, as shown in FIG. 5, a torque ripple in which the torque periodically fluctuates due to a change in the rotation angle of the rotor both when power is not supplied and when power is supplied.

On the other hand, in the present embodiment, the position near the slot connection portion, that is, the position of the front edge of the N pole and the front edge of the S pole is shifted from the symmetric position by half the size of the magnet pitch. , The phases of the fluctuation cycles of the torque generated by the N pole and the S pole due to the rotation angle are shifted from each other by a half wavelength. As a result, torque ripples generated on the N-pole side and the S-pole side cancel each other out, and as shown in FIG. 6, substantially constant torque can be obtained in a predetermined rotation angle range both when power is not supplied and when power is supplied.
Therefore, it becomes easy to precisely control the rotation angle of the rotor.

In the example shown in FIG. 3, the case where the plate magnets are arranged in close contact with each other has been described. However, similar effects can be obtained even when the plate magnets or the arc-shaped magnets are arranged at intervals as shown in FIG. be able to. Further, in the embodiment shown in FIG. 1, the slot connecting portions 48 and 49 are brought into close contact with each other to form a substantially slotless structure.
An air gap may be formed in 49.

Next, the operation of the throttle valve control device 10 will be described. (1) During normal driving The normal driving mode of the vehicle is ISC (idle speed control).
l) Normal driving, cruise control, etc. The opening of the throttle valve 13 in each mode is determined based on an engine operating state such as an accelerator pedal depression amount and an engine speed.
The control current calculated by the CU is supplied to the coils 52 and 57 according to the calculated opening. Since the torque for rotating the rotor 41 generated when the coils 52 and 57 are energized is greater than the urging force of the return spring 17, the rotor 41 can rotate against the urging force of the return spring 17.

The opening of the throttle valve 13 which rotates with the rotation of the rotor 41 is detected by the rotation angle sensor 30 and fed back to the ECU. The control current supplied from the ECU to the coils 52 and 57 is adjusted based on the opening signal. By detecting the opening of the throttle valve 13, the torque acting on the rotor 41 is prevented from fluctuating due to a temperature change or the like, and the opening of the throttle valve 13 can be controlled with high accuracy.

(2) At the time of failure The throttle opening 13 required by the ECU and the actual throttle valve 1 detected by the rotation angle sensor 30 are calculated.
If the opening degree of the throttle valve 3 does not match, it is determined that the opening degree control of the throttle valve 13 by the ECU has failed, and
Sends a signal to close the throttle valve 13. Then, since the throttle valve 13 returns to the fully closed position by the urging force of the return spring 17, the throttle valve 13 can be prevented from being excessively opened.

Further, since the ECU is provided with a sub-ECU that constantly diagnoses a failure of the ECU, if the ECU fails, the coils 52 and 5 are instructed by the sub-ECU.
The control current supplied to 7 is cut off. Therefore, EC
Even if U fails, the throttle valve 13 can be fully closed by the urging force of the return spring 17.

(Second Embodiment) FIG. 7 shows a torque motor according to a second embodiment of the present invention. The substantially same parts as those in the first embodiment are denoted by the same reference numerals. In the second embodiment, the stator core 4
51 and 461 are arranged almost symmetrically, and the two slot connecting portions 481 and 491 are 180 ° in the circumferential direction of the rotor 41.
It is on the opposite symmetrical position. Solenoid parts 50, 55
Is located 180 ° opposite to the slot connecting portions 481 and 491 with the rotor 41 interposed therebetween.

An angle of 1 from the 180 ° opposite side of the outer periphery of the rotor 41 with respect to the plurality of plate magnets 43a of one magnetic pole in the circumferential direction.
A plurality of plate magnets 44a of the other magnetic pole are provided at positions shifted by / 2A. As in the first embodiment, the plurality of plate magnets 43a and 44a have the same size and are arranged by being adhered to the outer periphery of the rotor core 42.

FIG. 8 is a schematic diagram for explaining the relationship between the positions of the magnetic poles on the stator side and the positions of the magnets generated in the torque motor having the configuration shown in FIG. In the second embodiment, as in the first embodiment, when the front edge of the S pole of the stator in the rotation direction of the rotor corresponds to the edge of the arranged magnet pitch, the front edge of the N pole is: Corresponds to the center of the magnet pitch. Therefore, similarly to the first embodiment, the phases of the periods of the fluctuations caused by the rotation angles of the torque generated at the N pole and the S pole are shifted from each other by a half wavelength. As a result, the torque ripple generated by the two magnetic poles is canceled, and a substantially constant torque can be obtained in a predetermined rotation angle range.

In the example shown in FIG. 8, the case where the plate magnets are arranged in close contact with each other has been described. However, similar effects can be obtained even when the plate magnets or the arc-shaped magnets are arranged at intervals as shown in FIG. be able to.

(Third Embodiment) FIG. 10 shows a torque motor according to a third embodiment of the present invention. The same reference numerals are given to substantially the same parts as those in the first and second embodiments. In the above-described first and second embodiments, the two solenoid portions 50 and 55 are provided so as to sandwich the rotor 41 in order to improve the response speed of the torque motor.
Is provided on the stator, but as shown in FIG. 10, a single solenoid unit 50 may be used to reduce the size and weight of the torque motor. At this time, the relationship between the magnetic poles on the stator side and the positions of the plate magnets is the same as the schematic diagram shown in FIG.

In FIG. 10, the stator connecting portion 482 at the position facing the solenoid portion 50 and the stator connecting portion 492 on the opposite side are angled by 1 / 2A from the position on the 180 ° opposite side.
However, as in the second embodiment shown in FIG. 7, the stator connecting portions are provided symmetrically, and the positions of the plurality of two-pole plate magnets are set at an angle of 1/2 in the circumferential direction from the 180 ° opposite side.
Even in the configuration shifted by A, one solenoid unit 50 can be used. At this time, the relationship between the magnetic poles on the stator side and the positions of the plate magnets is the same as the schematic diagram shown in FIG.

(Fourth Embodiment) FIG. 11 is a schematic diagram for explaining the operation of the fourth embodiment of the present invention. In the above-described first to third embodiments, the two-pole stator is configured to surround substantially the entire outer periphery of the rotor 41. Therefore, as shown in FIGS. However, it is also possible to adopt a configuration in which the magnetic poles on the stator side are provided only in a part of the outer periphery of the rotor as shown in FIG.

(Fifth Embodiment) FIG. 12 is an enlarged sectional view of a rotor for explaining a fifth embodiment of the present embodiment.
The bar-shaped magnet 143a as one of a plurality of magnets forming one magnetic pole is illustrated in an enlarged manner. Rod magnet 143a
Is formed in a trapezoidal cross section, and is disposed on the outer periphery of the rotor core 142 in close contact with adjacent magnets.

In the fifth embodiment, an iron cylindrical member 60 as a magnetic material is mounted on the outer periphery of the rotor. Thereby, the outside of the plurality of bar-shaped magnets 143a is covered. Further, in this embodiment, when the edge of one magnetic pole of the stator corresponds to the edge of the magnet, the other magnetic pole allows the leading edge to be slightly shifted from the center of the magnet as a manufacturing tolerance. This shift amount is A / A from the center of the magnet, ie, from the edge of the magnet.
From the position of No. 2, it is allowed within a range of ± A / 12. Thereby, in the present embodiment, the size of the torque ripple generated can be suppressed to １ ／ or less of the torque ripple generated in both magnetic poles in the comparative example of FIG.

With this configuration, it is possible to satisfy the practicality as an actuator for driving the throttle valve. In addition, manufacturing advantages such as facilitation of the assembling work can be obtained. In order to realize more precise control of the throttle, the allowable value of the torque ripple is shown in FIG.
It is desirable to suppress the torque ripple to about 1/10 of the torque ripple generated in the comparative example.

In the above embodiments, the torque motor of the present invention is applied to the throttle valve control device. However, it goes without saying that the torque motor of the present invention can be applied to a flow control valve for any use.

[Brief description of the drawings]

FIG. 1 is a view showing a throttle valve control device using a torque motor according to a first embodiment of the present invention, as viewed from an arrow I in FIG. 2 with a cover removed.

FIG. 2 is a sectional view showing a throttle valve control device using a torque motor according to a first embodiment of the present invention.

FIG. 3 is a schematic diagram illustrating the operation of the torque motor according to the first embodiment of the present invention.

FIG. 4 is a schematic diagram illustrating the operation of the torque motor according to the first embodiment of the present invention.

FIG. 5 is a characteristic diagram showing a relationship between a rotation angle and a torque by a torque motor of a comparative example.

FIG. 6 is a characteristic diagram showing a relationship between a rotation angle and a torque according to the first embodiment of the present invention.

FIG. 7 is a view illustrating a torque motor according to a second embodiment of the present invention.

FIG. 8 is a schematic diagram illustrating the operation of a torque motor according to a second embodiment of the present invention.

FIG. 9 is a schematic diagram illustrating the operation of a torque motor according to a second embodiment of the present invention.

FIG. 10 is a view illustrating a torque motor according to a third embodiment of the present invention.

FIG. 11 is a schematic diagram illustrating the operation of a torque motor according to a fourth embodiment of the present invention.

FIG. 12 is an enlarged view showing a torque motor according to a fifth embodiment of the present invention.

FIG. 13 is a diagram illustrating a torque motor according to a comparative example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Throttle valve control device 11 Throttle body 12 Throttle shaft 13 Throttle valve 17 Return spring 40 Torque motor 41 Rotor 42 Rotor core (rotor main body) 43, 44 Magnet group 43a, 44a Plate magnet 45, 46 Core 48, 49 Slot connecting part 50, 55 solenoid part 52, 57 coil 60 cylindrical member

Claims (3)

[Claims] 1. A rotor comprising a pair of magnetic poles each formed by a magnet group in which a plurality of magnets are arranged, and a stator having a magnetic pole disposed opposite to the rotor and excited by a solenoid unit. When the front edge of one pole of the stator corresponds to the edge of the magnet of one pole of the rotor, the front edge of the other pole of the stator is substantially the same as the magnet of the other pole of the rotor. A torque motor, which is disposed so as to correspond to the center. 2. The torque motor according to claim 1, wherein the magnet has a flat shape. 3. The rotor according to claim 1, wherein the substantially center is a position within 1/12 of a magnet pitch of the rotor from a position at which a magnet of the other magnetic pole of the rotor is bisected in a circumferential direction. 3. The torque motor according to any one of 1 and 2.