JP2000092808A - Torque motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a torque motor which can surely stop at a prescribed rotational angle when the motor is not energized. SOLUTION: The edges of the magnetic poles of a second stator 60 are formed at positions where the edges are shifted from the edges of the magnetic poles of a first stator 50 in a peripheral direction surrounding a rotor 41. When a second coil 64 is energized, two poles of an N-pole and an S-pole are generated in a second stator core 61. Consequently, detent torque which holds the rotor 41 at a prescribed angle is developed. When a first coil 54 is not energized and the second coil 64 is energized, the position at which the rotor 41 is stopped by the second stator 60 can be set arbitrary by changing the angular deviation between the first and second stators 50 and 60.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a torque motor used as an actuator for a throttle device or the like of an internal combustion engine.

[0002]

2. Description of the Related Art Conventionally, a rotor in which a permanent magnet attached to the outer periphery of a rotor core forms a pair of magnetic poles, a stator core formed of a magnetic material surrounding the rotor, and a pair of magnetic poles formed in the stator core by energizing the rotor. There is known a torque motor provided with a coil unit that generates a torque. Such a torque motor can be used as an actuator that controls the opening of a throttle valve provided in a throttle device that adjusts a flow path area of an intake passage of an internal combustion engine.

[0003] When the coil section cannot be energized due to a disconnection of the coil section or a failure of the control device, the rotation angle of the rotor is set to a state in which the internal combustion engine can be evacuated at low speed. It is desirable to correspond to an intermediate opening (for example, 10 °) slightly opened from the fully closed position of the throttle valve.

Conventionally, an opener spring for rotating the rotor in a fully open direction and a return spring for rotating the rotor in a fully closed direction are used to set the rotation angle of the rotor when no power is supplied, and the rotor stops at a predetermined angle. Was so balanced. Further, as disclosed in JP-A-8-228466, by providing a magnetic resistance portion at a predetermined position of the stator, the direction of the magnetic force when the coil is not energized is set, and the detent torque generated thereby is used. A torque motor that holds a rotor at a predetermined position is known.

[0005]

However, in the torque motor using the above-described opener spring and return spring, the number of parts increases, the weight increases, and mechanical parts are required. There was a problem of reliability. Further, in a torque motor using a detent torque generated by a magnetic force when the coil is not energized, the relationship between the rotation angle and the magnitude of the torque is linear as shown in FIG. The torque gradient could not be increased, and it was difficult to keep the rotor stop angle constant.

The present invention has been made to solve such a problem, and an object of the present invention is to provide a torque motor that can be reliably stopped at a predetermined rotation angle when no power is supplied.

[0007]

According to a first aspect of the present invention, there is provided a torque motor having a magnetic pole formed by a permanent magnet and a first coil portion disposed on the outer periphery of the rotor. A first stator that is excited to form a magnetic pole, and a second stator that generates a detent torque that maintains the rotor at a predetermined rotation angle when power is not supplied to the first coil unit. Therefore, the rotor can be stopped at a predetermined rotation angle when the first coil portion is not energized.

According to the second aspect of the present invention, the second stator is formed such that the edges of the magnetic poles are shifted in the circumferential direction with respect to the first stator. Therefore, the first
The angle at which the rotor stops when power is not supplied to the coil portion can be set to a desired position.

According to the third aspect of the present invention, the second stator generates a detent torque by a magnetic force generated by energizing the second coil portion. Therefore, when the first coil portion is energized, the second coil portion is de-energized, thereby eliminating the influence of the torque generated by the second stator and keeping the torque generated by the torque motor constant. It will be easier.

According to the torque motor of the present invention, the second stator generates the detent torque by the permanent magnet. Therefore, the structure of the second stator can be simplified, and the torque motor can be reduced in size and weight.

According to the torque motor described in claim 5 of the present invention, the torque generated by the second stator is smaller than the torque generated by the first stator. for that reason,
While the first coil is energized, the effect of the torque generated by the second stator can be reduced.

[0012]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a first embodiment of the present invention; (First Embodiment) FIG. 2 shows a throttle valve control device using a torque motor according to a first embodiment of the present invention. The throttle valve control device 10 shown in FIG. 2 does not have a mechanism mechanically linked to the accelerator that adjusts the opening of the throttle valve 13 according to the accelerator 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, a torque motor 40 is constituted by a rotor 41, a first stator 50, and a second stator 60.

The rotor 41 comprises a rotor core 42 press-fitted and fixed to the throttle shaft 12, and permanent magnets 43 and 44 provided on the outer periphery of the rotor core 42 on the opposite side in the radial direction. The permanent magnets 43 and 44 are magnetized in the radial direction of the rotor 41, and one radial outside is an N pole and the other is an S pole. As the permanent magnets 43 and 44, it is preferable 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.
Other permanent magnets such as ferrite magnets can be used. As the permanent magnets 43 and 44, a magnet group including a plurality of plate magnets can be used.

FIG. 1 is a schematic view of the torque motor 40 viewed from the direction I in FIG. The first stator 50 is formed by a first stator core 51 and a first coil 54 as shown in FIG. The first stator core 51 is formed of a magnetic material such as iron, and is formed in a substantially U-shape integrally with the first teeth portion 52 formed so as to surround the rotor 41 and the first teeth portion 52. It comprises a first arm 53. The first coil 54 is formed by winding the first coil 54 around the first arm 53. The first teeth portion 52 has slots 55, 5
6 are formed.

The second stator 60 is the first stator 50
And is formed by the second stator core 61 and the second coil 64. Second stator core 6
Reference numeral 1 denotes a configuration similar to that of the first stator core 51, and includes a second teeth portion 62 and a second arm portion 63 formed of a magnetic material. In the second teeth portion 62, slot portions 65 and 66 serving as boundaries between magnetic poles are formed.
The second stator 60 is formed at a position where the edge of the magnetic pole is shifted by a predetermined angle in the circumferential direction surrounding the rotor 41 with respect to the first stator 50. The end of the torque motor 40 is
Covered by Note that FIG. 2 does not show a positional relationship based on the circumferential displacement between the first stator 50 and the second stator 60 described above, and illustrates a case where there is no circumferential displacement for convenience.

By energizing the first coil 54,
Two poles of an N pole and an S pole are generated in the first stator core 51. Rotor 4 generated by permanent magnets 43 and 44
The magnetic pole on the one side is attracted to the edge of the magnetic pole on the stator side generated mainly by energization, so that a torque for rotating the rotor 41 is generated. As shown in FIG. 3, a substantially constant torque is applied to the rotor 41 by the first stator 50 in a predetermined angle range. One end of the angle range in which this almost constant torque is obtained corresponds to the fully closed position of the throttle valve,
By fixing the throttle shaft and the rotor 41 so that the other end corresponds to the fully open position, it becomes easy to precisely control the rotation angle of the rotor 41. In addition, when the second coil 64 is energized, two poles of an N pole and an S pole are generated in the second stator core 61. As a result, a detent torque for holding the rotor 41 at a predetermined angle is generated.

Since the edge of the magnetic pole of the second stator 60 is formed at a position shifted in the circumferential direction surrounding the rotor 41 with respect to the edge of the magnetic pole of the first stator 50, the first coil 5
When the second coil 64 is energized without energizing 4, the angle at which the torque applied to the rotor 41 by the second stator switches from positive to negative, that is, the position at which the rotor 41 stops,
By changing the magnitude of the angle deviation between the first stator 50 and the second stator 60, the position can be set to an arbitrary position. In the present embodiment, as shown in FIG. 3, the rotor 41 is set to stop at a position opened by a predetermined angle from a position corresponding to the fully closed throttle. Also,
Unlike the conventional example shown in FIG. 6, since the gradient of the torque fluctuation near the angle at which the torque switches from positive to negative is large,
The rotor 41 can be stopped at a predetermined angle more reliably.

Since the length of the second stator core 61 in the axial direction is shorter than that of the first stator core 51, the maximum value of the magnetic force generated by the second stator 60 is generated by the first stator 50. Smaller than the maximum value of the magnetic force. Therefore, as shown in FIG.
The maximum value of the detent torque applied to the rotor 41 by 0 is smaller than the maximum value of the torque applied to the rotor 41 by the first stator 50. Therefore, substantially constant torque is applied to the rotor 41 within a predetermined angle range. In addition, a configuration may be adopted in which the second coil is not energized while the first coil is energized, and the second coil is energized when the first coil is not energized.

Next, the operation of the throttle valve control device 10 will be described. The ISC (id
le speed control), normal driving, cruise control, etc. The opening of the throttle valve 13 in each mode is calculated by the ECU based on the engine operating state such as the accelerator pedal depression amount and the engine speed, and the control current corresponding to the calculated opening is supplied to the first coil 54. You. Depending on the direction of the current flowing through the first coil 54, a torque for rotating the rotor 41 in the forward and reverse directions is generated, and the throttle valve 13 can be rotated in the opening direction and the closing direction.

The opening of the throttle valve 13 is determined by the rotation angle sensor 3
0 is detected and fed back to the ECU. The control current supplied from the ECU to the coil 54 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.
Can be controlled with high accuracy.

When the first coil 54 is not energized, such as when the ECU fails or the first coil 54 is disconnected, the magnetic pole of the second stator 60 generated by energizing the second coil 64 is detented. Generate torque. The opening degree of the throttle valve 13 is an opening degree opened by a predetermined angle from the fully closed position, and a small amount of air can be continuously supplied to the engine.

(Second Embodiment) FIG. 4 is a schematic view of 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. The first stator 50 is the first
The configuration is the same as that of the embodiment. The second stator 70 is provided at an axial end of the first stator 50 and is formed by a second stator core 71 and a permanent magnet 74. Second
The stator core 71 includes a second teeth portion 72 and a second arm portion 73 formed of a magnetic material. Second
The permanent magnet 74 connected to the arm 73 of the
The N-pole and S-pole magnetic poles are formed on the stator 70 of FIG.
In the second teeth portion 72, slot portions 75 and 76 which are boundaries between magnetic poles of the second stator 70 are formed.
The second stator 70 is formed at a position where the edge of the magnetic pole is shifted by a predetermined angle in the circumferential direction surrounding the rotor 41 with respect to the first stator 50.

According to the second embodiment, since the magnetic poles of the second stator 70 are formed by the permanent magnets 74, there is no need to provide a coil portion on the second stator 70, and the torque is higher than in the first embodiment. The structure of the motor can be simplified.

(Third Embodiment) FIG. 5 is a schematic view of 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. First stator 50
Has the same configuration as the first and second embodiments. An annular member 81 made of a magnetic material and covering the outer periphery of the stator 41 is provided at an axial end of the first stator 50. On the inner periphery of the annular member 81, arc-shaped permanent magnets 82 and 83 are provided. These annular member 81, permanent magnet 82,
The second stator 80 is configured by 83. The permanent magnets 82 and 83 are magnetized in the radial direction, and one generates an N pole of the second stator 80 and the other generates an S pole. The edge of the magnetic pole of the second stator 80 is formed at a position shifted from the edge of the magnetic pole of the first stator 50 by a predetermined angle.

In the first and second embodiments described above, the stator core having the teeth and the arm is excited to form the magnetic poles in the second stator. In this embodiment, the annular member 81 and the permanent magnet are formed. The magnetic poles of the second stator are formed by 82 and 83. This has the effect of reducing the size and the number of parts of the torque motor. 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 schematic diagram showing a torque motor according to a first embodiment of the present invention.

2 shows a throttle valve control device using a torque motor according to a first embodiment of the present invention; FIG.
It is sectional drawing cut | disconnected in the position corresponding to -B line.

FIG. 3 is a characteristic diagram showing a magnitude of a torque generated by a first stator and a second stator in the torque motor according to the first embodiment of the present invention.

FIG. 4 is a schematic diagram showing a torque motor according to a second embodiment of the present invention.

FIG. 5 is a schematic diagram illustrating a torque motor according to a third embodiment of the present invention.

FIG. 6 is a characteristic diagram showing the magnitude of torque generated when no power is supplied by a conventional torque motor.

[Explanation of symbols]

 Reference Signs List 10 throttle valve control device 11 throttle body 12 throttle shaft 13 throttle valve 40 torque motor 41 rotor 50 first stator 51 first stator core 54 first coil 60 second stator 61 second stator core 64 second coil

Claims (5)

[Claims] A rotor having a magnetic pole formed by a permanent magnet; a first stator disposed on an outer periphery of the rotor and energized by energizing a first coil to generate a magnetic pole; A second stator disposed on an outer periphery and generating a detent torque for maintaining the rotor at a predetermined rotation angle when the first coil portion is not energized. 2. The torque motor according to claim 1, wherein the second stator is formed such that edges of magnetic poles are shifted in a circumferential direction with respect to the first stator. 3. The method according to claim 2, wherein the second stator includes at least a first stator.
3. The torque motor according to claim 2, wherein the detent torque is generated by a second coil unit that is energized when the coil unit is not energized. 4. The torque motor according to claim 2, wherein the second stator generates the detent torque by using a permanent magnet. 5. The torque motor according to claim 1, wherein the detent torque is smaller than a torque generated by the first stator.