JPH11225465A - Torque motor and throttle device using the same - Google Patents

Abstract

(57) [Problem] To provide a torque motor capable of setting the angle at which the rotor stops when no power is supplied to a desired angle. SOLUTION: A teeth part 46 has a low magnetic resistance part 461.
High magnetic resistance portions 46 on both sides in the circumferential direction with respect to the rotor 41
2, 463 are formed. Similarly, the teeth portion 47 includes a low magnetic resistance portion 471 and high magnetic resistance portions 472, 47.
And 3. The angle formed between the slot connecting portion 48 and the central portion of the low magnetic resistance portion 461 and the angle formed between the slot connecting portion 49 and the central portion of the low magnetic resistance portion 471 are:
Since it is formed to be smaller than 90 degrees, the angle at which high magnetic resistance portion 462 surrounds rotor 41 is smaller than the angle at which high magnetic resistance portion 463 surrounds rotor 41. Similarly, the angle at which high magnetic resistance portion 472 surrounds rotor 41 is smaller than the angle at which high magnetic resistance portion 473 surrounds rotor 41.

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, as shown in FIG. 5, a plurality of permanent magnets 143 adhered to the outer periphery of a rotor core 142.
a and a rotor group in which a group of magnets 143 and 144 formed of a pair of magnetic poles form a pair of magnetic poles, and a stator core 145 formed of a magnetic material surrounding the rotor 141.
And a coil 152 that generates a pair of magnetic poles in the stator core 145 when energized.
Forty are known. Such a torque motor 140
The throttle shaft 112 of the throttle device 110 for adjusting the flow passage area of the intake passage of the internal combustion engine can be fixed to the rotor 141 and used as an actuator for controlling the rotation of the throttle valve 113.

When the coil 152 cannot be energized due to a disconnection of the coil 152 or a failure of the control device, the rotation angle of the rotor 141 is set to a state in which the internal combustion engine can be evacuated at a low speed. , Throttle valve 113
Intermediate opening slightly opened from fully closed position (for example, 10 °)
It is desirable to respond to Conventionally, an opener spring for rotating the rotor 141 in a fully open direction and a return spring for rotating the rotor 141 in a fully closed direction are used to set the rotation angle of the rotor 141 when no power is supplied, and the rotor 141 stops at a predetermined angle. Was so balanced.

[0004]

In a conventional throttle device 110 using a torque motor 140 as shown in FIG. 5, a return spring and an opener spring may be omitted in order to simplify the structure and reduce the weight. In this case, if the coil 152 is not energized, the gap between the one magnet group 143 and the other magnet group 144 is opposed to the portion where the radial cross-sectional area of the stator core 145 is large and the magnetic resistance is low as shown in FIG. , The rotor 141 stops. This is because the energy required for the magnetic flux to flow between the permanent magnets 143a and 144a facing one magnetic pole of the rotor 141 and the other magnetic pole is minimized.

[0005] The stator core 145 has a high magnetic resistance due to its small cross-sectional area in the radial direction, and a pair of slot connecting portions 148 and 149 serving as boundaries between the magnetic poles of the stator core 145.
Are formed on the opposite side of the rotor 141 by 180 degrees. Since the magnetic resistance of the stator core 145 is generally low between the slot connecting portions 148 and 149, the center of the low magnetic resistance portion is substantially 90 degrees in the circumferential direction from the slot connecting portions 148 and 149. In the position. Therefore, the magnet group 14 of the rotor 141 can be
When the gap between the magnet group 3 and the magnet group 144 stops at a position facing the low magnetic resistance portion of the stator core 145, each magnet group 14
The centers of 3, 144 are located at positions corresponding to the slot coupling portions 148, 149.

When the coil 152 is energized, a magnetic pole is generated in the stator core 145, and the torque motor 140
A substantially constant torque can be generated in an angle range rotated substantially the same in the forward and reverse directions with reference to the position shown in FIG. Therefore, when power is not supplied to the rotor 1
The position where 41 stops is substantially the center position of the angular range where the torque motor 140 generates a substantially constant torque.

In the throttle device 110 to which the torque motor 140 is applied, one end of an angle range in which the torque motor 140 generates a substantially constant torque corresponds to the fully closed position of the throttle valve 113 and the other end corresponds to the fully open position.
As shown in FIG. 5, the throttle opening when no power is supplied is substantially intermediate between the fully closed position and the fully opened position. Therefore, a large amount of air is supplied at the time of evacuation traveling, and there is a problem that it is difficult to perform evacuation traveling at low speed.

The fully closed position of the throttle valve 113 approaches the stop position of the rotor 141 when no power is supplied, that is, the throttle valve 11 is moved to a position where the throttle opening is small when no power is supplied.
3 so that the rotor 141 and the throttle shaft 112 are stopped.
However, in this case, the fully open position of the throttle valve 113 is out of the range of the flat torque characteristic of the torque motor 140. In order to secure a predetermined angle at which a substantially constant torque can be generated, the torque generation angle range of the torque motor 140 must be increased. In order to increase the torque generation angle range, it is necessary to use many permanent magnets of the rotor 141, and accordingly, it is necessary to increase the volume of the stator core 145. Therefore, the torque motor 1
However, there is a problem that the weight of the H.40 increases and the manufacturing cost increases.

An object of the present invention is to solve the above problems,
An object of the present invention is to provide a torque motor in which an angle at which a rotor stops when power is not supplied can be made closer to one end of a range in which torque is generated in the same direction. Another object of the present invention is to provide a throttle device capable of reducing the throttle opening when no power is supplied.

[0010]

According to the torque motor of the present invention, one of the low magnetic resistance portions of the stator core is located closer to the other boundary than the one boundary of the magnetic poles generated in the stator core. And the other low magnetic resistance portion is located closer to one boundary than the other boundary of the magnetic pole generated in the stator core. When the rotor is not energized, the boundary of the magnetic poles on the outer peripheral surface is directed to a position facing the low magnetic resistance portion of the stator core, so that the angle at which the rotor stops can be made closer to one end of the range in which torque is generated in the same direction.

According to the torque motor according to the second aspect of the present invention, the control angle range of the rotor is substantially constant between the rising portion where the generated torque increases and the falling portion where the generated torque decreases. Since the torque is generated from one end to the other end of the central portion, the rotation of the rotor can be stably controlled in a wide range with a minimum amount of the permanent magnet.

According to the throttle device of the present invention, one end of the control angle range of the rotor corresponds to the fully closed position of the valve member, and the other end corresponds to the fully opened position of the valve member. Further, when the rotor rotates in the direction in which the throttle valve opens, the edge on the side where the rotor magnet comes to the magnetic pole of the stator core is the front edge of each magnetic pole of the stator core, and the other edge is the rear edge. Each of the low magnetic resistance portions is formed at a position closer to the front edge than the rear edge of the magnetic pole. Therefore, the throttle opening of the throttle device can be brought close to the fully closed position when no power is supplied. Therefore, when the solenoid is not energized, the limp-home running can be performed at a low speed, which is safe.

[0013]

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 device using a torque motor 40 according to a first embodiment of the present invention. The throttle device 10 shown in FIG. 2 has no mechanism mechanically linked to the accelerator for adjusting the opening of the throttle valve 13 in accordance with the accelerator depression amount, and adjusts the opening of the throttle valve 13 only by the torque motor 40. Is what you do.

The throttle body 1 of the throttle device 10
1 is a throttle shaft 1 through bearings 15 and 16
2 is rotatably supported. The throttle valve 13 is formed in a disk shape, and is fixed to the throttle shaft 12 with screws 14. When the throttle valve 13 rotates together with the throttle shaft 12, the flow passage area of the intake passage 11a formed by the inner wall of the throttle body 11 is adjusted, and the flow rate of intake air passing through the intake passage 11a is controlled.
The throttle shaft 12 and the throttle valve 13 constitute a valve member described in the claims.

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 defines the fully closed position of the throttle valve 13 by locking the throttle lever 21. 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 engine 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.

A rotor core 42 of the torque motor 40 is fixed to the other end of the throttle shaft 12. The rotor core 42 is formed in a cylindrical shape from a magnetic material such as iron. The end of the torque motor 40 is covered by the cover 20. FIG. 1 is a schematic diagram for explaining the opening degree of the torque motor 40 and the throttle valve 13 of the throttle device 10 according to the present embodiment. The rotor 41 includes a rotor core 42 and permanent magnet groups 43 and 44. The permanent magnet groups 43 and 44 each include six flat permanent magnets 4.
This is a group of magnets composed of 3a and 44a, which are bonded and fixed to the outer periphery of the rotor core 42. Permanent magnets 43a, 4
4a are arranged in an arc shape on the circumference of the rotor core 42 as shown in FIG. 1 in a state of being magnetized in one direction in the thickness direction. Therefore, the permanent magnet groups 43 and 44 are substantially radially magnetized from the center of the rotor 41. Since the permanent magnet 43a and the permanent magnet 44a are magnetized in opposite directions in the radial direction, the rotor 41 has magnetic poles forming a pair of an N pole and an S pole. Permanent magnet 43
Reference numerals a and 44a denote so-called rare earth magnets, such as neodymium and samarium-cobalt, which generate a high magnetic force.

The stator core 45 is formed by laminating thin plates made of a magnetic material in the axial direction of the throttle shaft 12.
The rotor 41 is formed of teeth 46 and 47 and arm 51 that constitute the magnetic poles of the stator core 45 surrounding the outer periphery of the rotor 41. The rotor 4 is provided on the inner walls of the teeth 46 and 47.
1 is formed so as to be rotatable. Slot connecting portions 48 and 49 having a small cross-sectional area in the radial direction of the rotor 41 are formed between the teeth 46 and the teeth 47, and serve as boundaries between the magnetic poles of the stator core 45. The slot connecting portion 48 and the slot connecting portion 49 are provided at symmetric positions on the opposite side of the rotor 41 by 180 degrees in the circumferential direction. The vicinity of the boundary between the magnetic poles of the teeth portions 46 and 47 is called the magnetic pole edge, and the edge on the side where the permanent magnet comes when the rotor 41 rotates in the opening direction of the throttle valve 13 shown in FIG. , 47a and the other edge to the trailing edge 46b, 4
7b.

The teeth portion 46 is formed with a low magnetic resistance portion 461 having a large sectional area in the radial direction of the rotor 41.
The teeth 46 are formed so that the cross-sectional area gradually decreases in the radial direction toward the edges 46a and 46b of the magnetic poles. Thus, high magnetic resistance portions 462 and 463 are formed on both sides of the low magnetic resistance portion 461 in the circumferential direction with respect to the rotor 41. Similarly, the teeth part 47 is formed by a low magnetic resistance part 471 and high magnetic resistance parts 472 and 473. The angle θ _A formed between the slot connecting portion 48 and the central portion of the low magnetic resistance portion 461 is equal to the angle formed between the slot connecting portion 49 and the central portion of the low magnetic resistance portion 471, and is formed to be smaller than 90 degrees. Have been. Therefore, the low magnetic resistance portion 461 is located at the rear edge 46 b of the magnetic pole of the teeth portion 46.
At a position closer to the front edge 46a. That is, the angle at which the high magnetic resistance portion 462 surrounds the rotor 41 is different from that of the high magnetic resistance portion 4.
63 is smaller than the angle surrounding the rotor 41.
Similarly, the angle at which high magnetic resistance portion 472 surrounds rotor 41 is smaller than the angle at which high magnetic resistance portion 473 surrounds rotor 41.

The arm portion 51 is formed in a substantially U-shape. One end is connected to the low magnetic resistance portion 461 of the teeth portion 46 and the other end is connected to the low magnetic resistance portion 471 of the teeth portion 47. The arm unit 51 and the coil 52 wound around the arm unit 51 constitute a solenoid unit 50. Coil 52
, A magnetic pole is generated in the stator core 45. The magnetic poles of the rotor 41 are attracted by the magnetic poles of the stator core 45, so that the torque motor 40 generates a torque for rotating the rotor 41 in the opening direction of the throttle valve shown in FIG. be able to.

The wave washer 19 urges the throttle shaft 12 in one axial direction so that the throttle shaft 12 does not move in the axial direction even during vibration during engine operation. As a result, the state of sliding between the contact portion 31 and the substrate 32 does not change, so that the opening signal of the throttle valve 13 is interrupted, or the resistance on the substrate due to the contact portion 31 sliding with the substrate 32 with excessive force. Wear of the body or the contact portion 31 can be prevented. Further, since the axial position of the rotor 41 with respect to the stator core 45 does not change, torque fluctuations received by the rotor 41 can be suppressed.

FIG. 5 is a diagram showing a torque motor 140 according to a comparative example. The torque motor 140 is connected to the rotor core 14
A plurality of permanent magnets 143a, 1
A rotor 141 in which a pair of magnetic poles are formed by magnet groups 143 and 144 constituted by 44a, and a stator core 145 formed of a magnetic material surrounding rotor 141
And a coil 152 that generates a pair of magnetic poles in the stator core 145 when energized.

The stator core 145 includes the stator core 1
A pair of slot connecting portions 148 serving as boundaries of the 45 magnetic poles;
149 is formed 180 degrees opposite the rotor 141. The stator core 145 is connected to the slot connecting portion 14.
8 and the slot connecting portion 149, the cross-sectional area in the radial direction is large, and the magnetic resistance is low. The center of the low magnetic resistance portion is located at an angle of approximately 90 degrees in the circumferential direction from the slot coupling portions 148, 149.

FIG. 3 is a diagram showing the relationship between the rotation angle of the rotor and the magnitude of the generated torque by the torque motor according to the comparative example and the first embodiment. When the coil is energized, the torque has a rising portion where the generated torque increases, a falling portion where the generated torque decreases, and a central portion where a substantially constant torque is generated between the rising portion and the falling portion. Characteristics are obtained. The range and magnitude of torque generation are almost the same in the comparative example and the embodiment, and a substantially constant torque is generated in a range of about 90 degrees.

In the first embodiment and the comparative example, when the torque motor is applied to a throttle device as shown in FIG. 2, the rotation angle from the fully closed state to the fully opened state of the throttle valve is 90 degrees.
In order to generate a substantially constant torque in between, the fully closed position of the throttle valve as one end of the control angle range of the rotor corresponds to the negative end in the center where a substantially flat torque is obtained. The rotor 41 and the throttle shaft 12 are fixed so that the fully open position of the throttle valve corresponds to the center-side positive end as the other end of the rotor control angle range. In this embodiment and the comparative example, the rotation angle of the rotor is controlled in a range of about 90 degrees, that is, about 45 degrees on each of the positive side and the negative side with reference to the center of the center of the torque characteristic shown in FIG. ing. The control angle range of the rotor is
Since the angle range is substantially equal to an angle range in which a substantially constant torque can be generated, an angle range in which a substantially constant torque can be obtained with a minimum volume of the permanent magnets 43a and 44a and the stator core 45 can be secured.

When the coil is not energized, a detent torque is generated due to the difference in the magnitude of the magnetic resistance in the circumferential direction of the stator core surrounding the rotor. In the comparative example,
Since the magnetic resistance of the stator core 145 is low at an intermediate position between the slot connecting portions 148 and 149, that is, at a position 90 degrees in the circumferential direction from the slot connecting portions 148 and 149, the magnetic poles of the rotor 141 as shown in FIG. When the gap between the permanent magnet 143a and the permanent magnet 144a, which is the boundary of
When the center of 3, 144 is located at a position facing the slot connecting portions 148, 149, the energy required for the magnetic flux to flow between the permanent magnets 143a and 144a becomes the lowest and is stable. Therefore, the throttle valve 113
A detent torque is generated so that the rotor 141 stops at a position approximately 45 degrees from the fully closed position between the fully closed position and the fully closed position. Therefore, the throttle opening when the coil 152 is not energized is the fully closed position and the position A in FIG. 3, which is approximately the center of the fully opened position.

On the other hand, in the first embodiment, as shown in FIG. 1, the low magnetic resistance portions 461 and 471 have their centers located between the slot connecting portions 48 and 49 of the stator core 45 at an angle of more than 90 degrees in the circumferential direction. It is formed so as to form a small angle theta _a. For example, assuming that θ _A is 60 degrees, when the coil 52 is not energized, the gap between the permanent magnets 43 a and 44 a, which is the boundary between the magnetic poles of the rotor 41, faces the center of the low magnetic resistance portions 461 and 471. Therefore, the rotor 41 is stabilized at a position where the rotation angle is smaller by 30 degrees than the comparative example.
Therefore, a detent torque is generated such that the rotor 41 stops at a position B that is approximately 15 degrees from the fully closed position of the throttle valve 13. Therefore, the throttle valve 13 can be stopped at a position closer to the fully closed position than in the comparative example.

Therefore, according to the present embodiment, the torque characteristic at the time of energization is almost the same as that of the comparative example, and the position where the throttle valve 13 stops when the coil 52 is not energized can be closer to the fully closed position than the comparative example. it can. Next, the operation of the throttle device 10 will be described. The normal running mode of the vehicle includes ISC (idle speed control), normal driving, cruise control and the like. The opening of the throttle valve 13 in each mode is calculated by the ECU based on the engine operation state such as the accelerator pedal depression amount, the engine speed, and the like, and a control current corresponding to the calculated opening is supplied to the coil 52. Depending on the direction of the current flowing through the coil 52, the rotor 41
To generate a torque to rotate in the forward and reverse directions,
The throttle valve 13 can be turned 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 52 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 coil 52 is not energized, such as when the ECU fails or the coil 52 is disconnected, the opening of the throttle valve 13 is opened by about 15 degrees from the fully closed position, and a small amount of air is supplied to the engine. Since the supply can be continued, the limp-home run can be performed at a low speed. (Second Embodiment) FIG. 4 shows a torque motor 60 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 rotor 41 has the same structure as in the first embodiment.

In the first embodiment, the teeth 46, 47 of the stator core 45 are formed so that the cross-sectional area in the radial direction is reduced toward both ends and the magnetic resistance is increased, so that the low magnetic resistance portions 461, 471 are formed. Although the high magnetic resistance portions 462 and 472 and the high magnetic resistance portions 463 and 473 are formed on both sides, as in the second embodiment shown in FIG. The high magnetic resistance portions 662, 663, whose radial cross-sectional areas are small on both circumferential sides with respect to the rotor 41 of
672 and 673 may be formed. In each magnetic pole of the stator core 65, the angle at which one of the high magnetic resistance portions 662, 672 surrounds the rotor 41 is different from that of the other high magnetic resistance portion 663,
673 is formed smaller than the angle surrounding the rotor 41. Further, the stator core may be formed of a composite material partially different in magnetic resistance, and the high magnetic resistance portion and the low magnetic resistance portion may be provided.

In the embodiments of the present invention described above, a plurality of plate-like permanent magnets 43a and 44a magnetized in one direction are arranged to form the magnetic poles of the rotor 41, but each magnetic pole is radially attached. It can be formed of one magnetized permanent magnet, or a plurality of arc-shaped permanent magnets can be used. Further, in a plurality of embodiments of the present invention, the stator core is slotless without a break in the accommodation hole for accommodating the rotor, but between the teeth portion serving as one magnetic pole of the stator core and the teeth portion serving as the other magnetic pole. It is also possible to adopt a configuration with a gap.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a torque motor according to a first embodiment of the present invention as viewed in the direction of arrow I in FIG. 2 and a schematic diagram of a throttle device.

FIG. 2 is a sectional view showing a throttle device to which the torque motor according to the first embodiment is applied.

FIG. 3 is a characteristic diagram showing a relationship between a rotation angle and a magnitude of torque in the torque motor according to the comparative example and the first embodiment.

FIG. 4 is a view illustrating a torque motor according to a second embodiment of the present invention.

FIG. 5 is a schematic diagram of a torque motor and a throttle device according to a comparative example.

[Explanation of symbols]

 Reference Signs List 10 Throttle device 11 Throttle body 12 Throttle shaft (valve member) 13 Throttle valve (valve member) 40 Torque motor 41 Rotor 42 Rotor core 43, 44 Permanent magnet group 43a, 44a Permanent magnet 43b, 44b Permanent magnet 45 Stator core 46, 47 Teeth portion 46a, 47a Leading edge 46b, 47b Trailing edge 461, 471 Low magnetic resistance part 462, 472, 463, 473 High magnetic resistance part 48, 49 Slot connecting part 50 Solenoid part 51 Arm part 52 Coil part

Claims (3)

[Claims] A rotor having a pair of magnetic poles formed by permanent magnets; a pair of low magnetic resistance portions sandwiching the rotor; and a high magnetic resistance portion formed on both sides of the low magnetic resistance portion in the circumferential direction with respect to the rotor. A stator core that surrounds the rotor, and a solenoid portion that generates a magnetic pole in the stator core when energized, wherein one of the low magnetic resistance portions is located on the other side of one boundary of the magnetic pole generated in the stator core. A torque motor located near a boundary, and the other low magnetic resistance portion is located closer to one boundary than the other boundary of magnetic poles generated in the stator core. 2. The control angle range of the rotor is from one end to the other end of a central portion where a substantially constant torque is generated between a rising portion where the generated torque increases and a falling portion where the generated torque decreases. The torque motor according to claim 1, wherein: 3. A throttle device using the torque motor according to claim 2, wherein: a throttle body forming an intake passage; and a valve member that rotates together with the rotor to adjust a flow passage area of the intake passage. Wherein one end of the control angle range corresponds to a fully-closed position of the valve member, and the other end corresponds to a fully-opened position of the valve member. The throttle device is also located near the front edge.