JP2001157432A - Torque motor and throttle device using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a torque motor which generates a desired torque and to provide a throttle device which uses the torque motor. SOLUTION: A rotor core 42 is formed in a disk shape, and a protrusion 43 which protrudes to the outside in the radial direction is installed in a position situated in the opposite direction by 180 deg.. Rotor magnets 44, 45 (not indicated in the figure) are arranged and installed alternately in the circumferential direction, and they are magnetized in the opposite direction of a shaft. Opposite cores 51, 52 at a stator core 50 are faced by forming a prescribed interval (d) from the rotor magnets 44, 45 in the direction of the shaft. The opposite core 52 comprises a protrusion part 52c which protrudes to the outside in the radial direction. When a current is made to flow to a coil 60, stator magnetic poles whose polarities are different are generated in the opposite cores 51, 52 on the side of a rotor 41 alternately in the circumferential direction. When the rotor 41 is turned in a valve-opening direction so as to be turned up to a part near a fully open position, the protrusion part 43 at the rotor core 42 is brought close to the protrusion part 52c at the stator core 50, and a reluctance torque is generated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a torque motor in which a rotor magnetic pole and a stator magnetic pole face each other at a predetermined interval in the direction of the rotation axis, and more particularly to a torque motor used for a flow control valve and the like, and a torque motor used therefor. Related to the throttle device.

[0002]

2. Description of the Related Art Conventionally, as a torque motor that generates torque within a control angle range defined by the number of rotor magnetic poles and stator magnetic poles, a predetermined interval is formed between a rotor magnetic pole and a stator magnetic pole in a rotation axis direction. Tokio Table 6
A torque motor as disclosed in Japanese Patent Publication No. 504901 is known. Such a torque motor can be used as an actuator of a valve device such as an intake flow control valve of an internal combustion engine.

In a configuration in which the rotor magnetic poles and the stator magnetic poles face each other with a predetermined interval in the direction of the rotation axis, for example, even if the number of magnetic poles of the rotor magnetic poles and the stator magnetic poles is increased, the diameter of the torque motor does not increase. Further, the generated torque increases as the number of magnetic poles increases.

[0004]

SUMMARY OF THE INVENTION In a torque motor in which a rotor magnetic pole and a stator magnetic pole are opposed to each other with a predetermined space therebetween in the direction of the rotation axis, the positions of the rotor magnetic pole and the stator magnetic pole having different magnetic poles are changed in the rotational direction. , A force attracting different magnetic poles acts in the rotational direction to generate torque. When the rotor magnetic poles and the stator magnetic poles having different polarities face each other in front of each other, a force for attracting the different magnetic poles acts in the rotation axis direction, so that no torque is generated. That is, since the generated torque is reduced at the boundary of the control angle range defined by the number of magnetic poles, the generated range of the torque that can be used as a torque drive source is narrowed. If the size of the torque motor is increased, the total generated torque increases, so that the torque required for driving can be generated even at the boundary of the control angle range. However, there is a disadvantage that the torque motor becomes large.

In a torque motor in which a rotor magnetic pole and a stator magnetic pole are opposed to each other with a predetermined interval in the direction of the rotation axis, when the temperature rises and the relative permeability of the rotor core and the stator core decreases, the generated torque decreases. However, when the temperature decreases and the relative magnetic permeability of the rotor core and the stator core increases, the generated torque increases. If the generated torque fluctuates due to the temperature change as described above, the rotational angle position cannot be controlled with high accuracy as a driving source.

As described above, the conventional torque motor cannot generate a desired torque due to a change in the rotational angle position and the temperature. Therefore, an object of the present invention is to provide a torque motor that generates a desired torque and a throttle device using the same. The torque motor that generates a desired torque is, for example, a torque motor that increases a generated torque at a predetermined rotation position, and another is a torque motor that prevents a torque fluctuation due to a temperature change.

[0007]

According to a first aspect of the present invention, there is provided a torque motor in which a rotor magnetic pole and a stator magnetic pole are opposed to each other at a predetermined interval in the direction of the rotation axis. Protrusions projecting outward or radially inward are provided on the rotor core and the stator core. When the rotor rotates and the protrusions provided on the rotor core and the stator core approach each other, suction force is generated between the protrusions, so-called reluctance torque is generated. Therefore, by adjusting the position where the protrusion is provided, it is possible to increase the generated torque at a desired rotation angle position without increasing the size of the torque motor.

The generated torque rapidly decreases as the boundary between the rotor magnetic pole and the stator magnetic pole having different polarities, in other words, the boundary between the magnetic poles having different polarities on the rotor core or the stator core approaches the position directly opposite to the front. According to the torque motor according to the second aspect of the present invention, since the protrusion is provided at the boundary between the magnetic poles having different polarities in the rotor core or the stator core, the rotor core approaches the position where the rotor magnetic poles having different polarities and the stator magnetic poles face directly in front. When the protrusions provided on the stator core and the protrusions approach each other, a reluctance torque is generated in which the protrusions attract each other. Conventionally, the torque that has decreased at the boundary of the control angle range defined by the number of magnetic poles increases, so that the angle range in which the torque is generated increases. Therefore, for example, as a drive source for driving a throttle valve of a throttle device,
When the torque motor described in (1) is used, the throttle valve can be driven to a position as close as possible to the fully open position.

According to the third aspect of the present invention, the stator magnetic pole and the rotor magnetic pole have the same number of magnetic poles. Comparing in the control angle range defined by the number of magnetic poles, it is better to make the number of magnetic poles of the stator magnetic pole and the rotor magnetic pole the same.
The generated torque increases as compared with increasing or decreasing the number of one magnetic pole.

According to a fourth aspect of the present invention, there is provided a torque motor in which a rotor magnetic pole and a stator magnetic pole are opposed to each other at a predetermined interval in the direction of the rotation axis.
The rotor core or the stator core is attached to a support member having a larger linear expansion coefficient than the rotor core or the stator core. When the temperature rises, the rotor core and the stator core approach each other due to expansion of the support member, and when the temperature decreases, the support member contracts due to the contraction of the rotor core and the stator core. As a result, when the temperature rises, the generated torque that decreases due to the decrease in the relative magnetic permeability is increased, and when the temperature decreases, the generated torque that increases due to the increase in the relative magnetic permeability decreases. Therefore, even if a temperature change occurs, the generated torque can be kept constant. As a material used as the support member, PP having excellent heat resistance as described in claim 5 is used.
S (polyphenylene sulfide) is desirable.

According to the throttle device of the present invention, the torque motor according to any one of claims 1 to 5 is used as a drive source of the throttle valve. Therefore, the generated torque can be increased at the angular position where the generated torque decreases. Therefore, the torque required to drive the throttle valve can be generated even in the fully closed position and the fully opened position. Further, the throttle valve can be driven with a constant torque even in a vehicle in which the ambient temperature changes drastically.

[0012]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a first embodiment of the present invention; (First Embodiment) FIG. 1 shows a throttle device using a torque motor according to a first embodiment of the present invention. In FIG.
The throttle device 10 is in a fully closed state. The throttle device 10 does not have a mechanism mechanically linked to an accelerator for adjusting the opening of the throttle valve 13 according to the accelerator pedal depression amount, and adjusts the opening of the throttle valve 13 only by the torque motor 40. .

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.

A plate-like intermediate member 20 is inserted through one end of the throttle shaft 12 so as to be rotatable with the throttle shaft 12. The intermediate member 20 is urged by a return spring 21 in the valve closing direction of the throttle device 10. The intermediate member 20 is locked by a stopper (not shown) in the valve closing direction in the vicinity of the fully closed position slightly closer to the valve opening side than the fully closed position.
The plate-shaped locking member 22 is fixed to the throttle shaft 12 and rotates together with the throttle shaft 12. Locking member 22
The throttle shaft 12 is urged by an opener spring 24 in the valve opening direction of the throttle device 10.
The urging force of the return spring 21 is larger than the urging force of the opener spring 24. The locking lever 23 formed on the locking member 22 is locked by the stopper screw 25 at the fully closed position. The intermediate member 20 and the locking member 22 contact each other between the fully open position and the vicinity of the fully closed position, and separate from the intermediate member 20 and the locking member 22 between the vicinity of the fully closed position and the fully closed position.

The rotation angle sensor 30 is disposed closer to the end of the throttle shaft 12 than the locking member 22, and has a sensor rotor 31, a contact portion 32 attached to the sensor rotor 31, and a resistor. The substrate 33 is formed. The sensor rotor 31 is fixed to the throttle shaft 12 and rotates together with the throttle shaft 12.
A constant voltage of 5 V is applied to the resistor applied to the substrate 33, and when the sliding position between the resistor and the contact portion 32 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 having a rotor 41, a stator core 50 and a coil 60 is provided. The end of the torque motor 40 is covered by a cover 65. The rotor 41 has a disk-shaped rotor core 42 press-fitted and fixed to the throttle shaft 12.
And rotor magnets 44 and 45 attached with an adhesive or the like to an end surface of the rotor core 42 on the side of the one of the rotation axes and on the side opposite to the throttle valve 13. As shown in FIG. 2, the rotor magnets 44 and 45 are formed in a fan shape having a central angle of 90 °, and are arranged alternately in the rotation direction. The rotor magnet 44 and the rotor magnet 45 are magnetized in the direction opposite to the rotation axis, and form four rotor magnetic poles having different polarities alternately in the rotation direction. Boundaries of four rotor magnetic poles are formed between the rotor magnets 44 and 45 having different polarities. The rotor core 42 is provided with a projection 43 projecting radially outward at a pair of boundary positions 180 ° opposite to each other among the boundaries of the rotor poles formed at four locations.

The structure of the stator core 50 will be described with reference to FIGS. 1, 3 and 4. Stator core 5 shown in FIG.
0 is a sectional view taken along line II of FIG. FIG. 3 is a view of the stator core 50 viewed from the side opposite to the rotor, and FIG. 4 is a view of the stator core 50 viewed from the side of the rotor. The stator core 50 includes opposed cores 51 and 52 which face the rotor magnets 44 and 45 at a predetermined interval d in the rotation axis direction,
It has opposing cores 51 and 52 and a rear core 53 connected on the side opposite to the rotor. The opposing cores 51 and 52 are alternately arranged in the rotation direction, and the coil 60 is wound around each opposing core. When a current is applied to each coil 60, the opposing cores 51 and 52 form stator magnetic poles having different polarities on the rotor side. Therefore, four stator magnetic poles having different polarities alternately in the rotation direction are generated in the opposed cores 51 and 52.

The opposing cores 51 and 52 are respectively
1a and 52a and mounting portions 51b and 52b. Further, the opposing core 52 has a protrusion 52c. The facing portions 51a and 52a are formed in a fan shape with a central angle of 90 °, and face the rotor magnets 44 and 45 with a space d in the direction of the rotation axis. Attachments 51b, 52b
Are located radially outward of the facing portions 51a and 52a.
a, 52a, which are thinner than the opposing portions 51a, 52a and farther from the rotor 41. The protruding portion 52c is provided at a boundary position between the opposing core 51 and the opposing core 52, that is, at a boundary position between the stator magnetic poles, continuously with the mounting portion 52b.
And is opposed to the rotor 41 at substantially the same interval d as the facing portion 52a.

Next, the operation of the throttle device 10 will be described with reference to FIG. FIG. 5 is a schematic view of the stator core 50 and the rotor 40 viewed from the stator core 50 side. In FIG. 5, the polarity in parentheses indicates the polarity of the rotor magnetic pole. Since the urging force of the return spring 21 is greater than the urging force of the opener spring 24, if the torque motor 40 does not generate torque, the throttle valve 13 is urged in the valve closing direction between the fully open position and the vicinity of the fully closed position. You. As shown in FIG. 5A, near the fully closed position, the positions of the rotor 41 and the stator core 50 are
The rotor magnet 44 and the opposing core 51 oppose each other, the rotor magnet 45 and the opposing core 52 oppose each other, and the rotor 41 is set to be slightly shifted in the valve opening direction. When a current is applied to the coil 60 such that the opposing core 51 on the rotor magnet side has the N-pole and the opposing core 52 has the S-pole, the rotor magnetic poles having the same polarity slightly oppose the stator magnetic poles in the valve opening direction. . Therefore, the rotor 41 and the throttle valve 13 rotate in the valve opening direction. The torque motor 40 generates a torque in the valve opening direction according to the amount of depression of the accelerator pedal, thereby adjusting the opening of the throttle valve 13 between the fully open position and the vicinity of the fully closed position.

When the rotor 41 rotates in the valve opening direction and further rotates from the intermediate position shown in FIG. 5B to the vicinity of the fully opened position shown in FIG.
And the protrusion 52c of the stator core 50 approach. Then, a suction force is generated between the protrusion 43 and the protrusion 52c, and a reluctance torque is generated.

The projections 43 and 52c are not formed, and the throttle valve 13 approaches the fully open position as shown in FIG.
5 and the opposing core 51, that is, when the rotor magnetic pole and the stator magnetic pole having different polarities face each other, the rotor magnets 44, 4
The suction force acting between the stator 5 and the opposing portions 51a, 52a of the stator core 50 is not in the rotation direction but in the rotation axis direction. Therefore, as indicated by a dotted line 101 in FIG. 6, the generated torque decreases near the fully open position. In contrast, in this embodiment,
When the rotor 41 approaches the fully open position, the protrusions formed on the rotor core 42 and the stator core 50 approach each other, and the solid line 10
Since the reluctance torque is generated as shown in FIG. 2, even if the rotor 41 approaches the fully open position as shown by the solid line 100, the generated torque does not decrease. Therefore, the throttle valve 13 can be driven to the fully opened position. If the size of the torque motor is increased, the generated torque is increased as a whole, so that the torque for driving the throttle valve 13 can be generated even in the vicinity of the fully open position, but there is a disadvantage that the size of the torque motor is increased. On the other hand, in the first embodiment, since the reluctance torque is generated near the fully open position, the throttle valve 13 can be driven to the fully open position without increasing the size.

The movement of the intermediate member 20 in the valve closing direction is locked by a stopper (not shown) near the fully closed position, and the locking member 22 rotates to the fully closed position. , The intermediate member 20 and the locking member 22 are separated. Between the vicinity of the fully closed position and the fully closed position, the urging force of the opener spring 24 acts on the locking member 22. Therefore, by flowing a current in the opposite direction between the fully-closed position and the fully-closed position between the vicinity of the fully-closed position and the fully-closed position, the torque motor 40 generates torque in the valve-closing direction. The opening degree of the throttle valve 13 is adjusted between the fully closed position.

(Second Embodiment) FIG. 7 shows a second embodiment of the present invention.
Shown in The same reference numerals are given to the same components as those in the first embodiment, and the description will be omitted. The rotor 70 includes a support member 71
, A rotor core 80, and rotor magnets 44 and 45. The support member 71 is made of resin using PPS or the like having excellent heat resistance, and is fixed to the throttle shaft 12. The linear expansion coefficient of the support member 71 is larger than that of the rotor core 80.
A concave portion 72 is formed on the outer peripheral wall of the support member 71 on the side opposite to the stator core. The recess 72 is not connected to the rotor core 80. The rotor core 80 is formed in an annular disk shape, and the inner peripheral wall of the rotor core 80 is connected to the outer peripheral wall of the support member 71 on the stator core side excluding the recess 72 by bonding or the like. The protrusion 81 is formed so as to protrude radially outward of the rotor core 80, similarly to the protrusion 43 of the first embodiment.

In general, the relative permeability of a magnetic material decreases as the temperature increases, and increases as the temperature decreases. Therefore, the interval d formed by the rotor 70 and the stator core 50 is
If the temperature hardly changes due to the temperature change, the generated torque decreases as the temperature increases, and the generated torque increases as the temperature decreases. As described above, if the generated torque increases or decreases due to the temperature change and a desired torque cannot be generated, the throttle opening cannot be controlled with high accuracy.

In the second embodiment, when the rotor core 80 is attached to the support member 71 having a larger linear expansion coefficient than the rotor core 80, when the temperature rises, the rotor magnets 44 and 45 approach the stator core 50 due to the expansion of the support member. Is lowered, the rotor magnets 44 and 45 move away from the stator core 50. Therefore, the change in the relative magnetic permeability due to the temperature change and the change in the interval d formed between the rotor core 80 and the stator core 50 cancel each other out, and it is possible to prevent a change in the generated torque due to the temperature change. In the second embodiment, the rotor core 80 is connected to the support member 71 having a larger linear expansion coefficient than the rotor core 80. However, the stator core may be attached to a support member having a larger linear expansion coefficient than the stator core.

In the above-mentioned plural embodiments showing the embodiment of the present invention, the torque generated at the boundary of the control angle range defined by the number of magnetic poles can be increased without increasing the size of the torque motor. A desired torque can be generated by preventing torque fluctuation due to temperature change.

In the above embodiments, the protrusions are provided radially outside the rotor core and the stator core. On the other hand, a protrusion may be provided radially inside the rotor core and the stator core. Further, the protrusions may be provided on both the radial inner side and the radial outer side of the rotor core and the stator core.

In the above embodiments, the torque motor of the present invention is applied to the throttle 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. Further, in the above plurality of embodiments,
Four poles were formed for both the rotor and stator poles.
The number of rotor magnetic poles and the number of stator magnetic poles may be increased or decreased depending on the application to which the torque motor is applied. Further, the rotor magnetic pole and the stator magnetic pole may have different numbers of poles.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a throttle device using a torque motor according to a first embodiment of the present invention.

FIG. 2 is a schematic arrow view showing the rotor viewed from a stator core side.

FIG. 3 is an arrow view of the steering core as viewed from a direction III in FIG. 1 with a cover removed.

FIG. 4 is a schematic arrow view showing the stator core as viewed from the rotor side.

FIGS. 5A and 5B are schematic explanatory diagrams showing a rotational position of a rotor with respect to a stator core, wherein FIG. 5A shows a position near a fully closed position, FIG. 5B shows an intermediate position, and FIG.

FIG. 6 is a characteristic diagram showing a relationship between a throttle opening and a generated torque.

FIG. 7 is a sectional view showing a torque motor portion of a throttle device according to a second embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 10 throttle device 11 throttle body 12 throttle shaft 13 throttle valve 40 torque motor 41 rotor 42 rotor core 43 protrusion 44, 45 rotor magnet 50 stator core 51, 52 opposed core 52c protrusion 60 coil 70 rotor 71 support member 80 rotor core 81 protrusion

Claims (6)

[Claims] A rotor having a plurality of magnets arranged in the rotation direction on one rotation axis direction side of a rotor core to alternately form a plurality of rotor magnetic poles having different polarities; a coil; and the rotor magnetic pole and a rotation axis direction. A plurality of opposing cores arranged so as to oppose each other at a predetermined interval, and a plurality of stator magnetic poles having alternately different polarities in the rotation direction by applying a current to the coil, the And a stator core formed on the side facing the rotor, wherein the rotor core and the stator core are provided with projections projecting at least either radially outward or radially inward. 2. The torque motor according to claim 1, wherein the protrusion is provided at a boundary between magnetic poles having different polarities in the rotor core or the stator core. 3. The torque motor according to claim 1, wherein the number of the stator magnetic poles is equal to the number of the rotor magnetic poles. 4. A rotor in which a plurality of magnets are arranged in the rotation direction on one rotation axis direction side of a rotor core to form a plurality of rotor magnetic poles having different polarities alternately; a coil; A plurality of opposed cores arranged so as to face each other at a predetermined interval, and a plurality of stator magnetic poles having alternately different polarities in a rotating direction by energizing the coil; And a stator core generated on a side opposite to the stator core, wherein the rotor core or the stator core is attached to a support member having a larger linear expansion coefficient than the rotor core or the stator core. 5. The torque motor according to claim 4, wherein said support member is PPS. 6. A throttle device comprising a throttle valve for adjusting an intake flow rate flowing through an intake passage, and using the torque motor according to claim 1 as a drive source for the throttle valve.