U.S. patent application number 11/525893 was filed with the patent office on 2007-01-18 for throttle valve control apparatus of internal combustion engine and automobile using the same.
This patent application is currently assigned to HITACHI LTD.. Invention is credited to Yoshikatsu Hashimoto, Yasuo Saito, Shigeru Tokumoto, Toshifumi Usui, Eisuke Wayama.
Application Number | 20070012288 11/525893 |
Document ID | / |
Family ID | 18623033 |
Filed Date | 2007-01-18 |
United States Patent
Application |
20070012288 |
Kind Code |
A1 |
Wayama; Eisuke ; et
al. |
January 18, 2007 |
Throttle valve control apparatus of internal combustion engine and
automobile using the same
Abstract
The invention provides a throttle valve control apparatus
provided with a throttle sensor which is in trouble at a low
possibility and has a long service life, whereby an accurate output
of a throttle opening degree can be obtained. The throttle valve
control apparatus of an internal combustion engine ahs a throttle
opening degree sensor constituted by a non-contact sensor using
hole elements.
Inventors: |
Wayama; Eisuke;
(Hitachinaka, JP) ; Usui; Toshifumi; (Hitachinaka,
JP) ; Hashimoto; Yoshikatsu; (Hitachinaka, JP)
; Tokumoto; Shigeru; (Hitachinaka, JP) ; Saito;
Yasuo; (Hitachinaka, JP) |
Correspondence
Address: |
CROWELL & MORING LLP;INTELLECTUAL PROPERTY GROUP
P.O. BOX 14300
WASHINGTON
DC
20044-4300
US
|
Assignee: |
HITACHI LTD.
TOKYO
JP
HITACHI CAR ENGINEERING CO., LTD.
IBARAKI-KEN
JP
|
Family ID: |
18623033 |
Appl. No.: |
11/525893 |
Filed: |
September 25, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10747983 |
Dec 31, 2003 |
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11525893 |
Sep 25, 2006 |
|
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09794209 |
Feb 28, 2001 |
6701892 |
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10747983 |
Dec 31, 2003 |
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Current U.S.
Class: |
123/399 ;
251/129.1 |
Current CPC
Class: |
F16K 37/0033 20130101;
F16K 37/0041 20130101; F02D 11/10 20130101; F02D 9/105 20130101;
G01D 5/145 20130101; F02D 11/106 20130101; F02D 2200/0404
20130101 |
Class at
Publication: |
123/399 ;
251/129.1 |
International
Class: |
F02D 11/10 20060101
F02D011/10; F16K 31/02 20060101 F16K031/02 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 6, 2000 |
JP |
2000-110540 |
Claims
1. A throttle valve control apparatus of an internal combustion
engine comprising: a throttle valve axis; a final gear fixed to
said throttle valve axis and transmitting a driving force of a
motor to said throttle valve axis; a throttle body supporting said
throttle valve axis; a throttle sensor detecting a rotation angle
of said throttle valve axis; and a cover attached to said throttle
body and covering said final gear; wherein said throttle sensor is
of a magnetic type having a magnet and a Hall element detecting a
change of a magnetic flux of said magnet, and wherein said magnet
and said Hall element are arranged between a surface in a side in
which a gear fixed to said throttle valve axis faces to said
throttle body, and an inner surface of said cover.
2. A throttle valve control apparatus of an internal combustion
engine as claimed in claim 1, wherein said magnet is attached to
said throttle valve axis, and said Hall element is attached to said
cover.
3. A throttle valve control apparatus of an internal combustion
engine as claimed in claim 1, wherein an output of said Hall
element forms a function of an opening degree of said throttle
valve.
4. A throttle valve control apparatus of an internal combustion
engine as claimed in claim 1, wherein a command value of said motor
is regulated on the basis of an electric signal output by said
throttle sensor.
5. A throttle valve control apparatus of an internal combustion
engine as claimed in claim 1, wherein said gear is constituted by a
metal plate fixed to said throttle valve axis, and a synthetic
resin portion forming teeth, and wherein said synthetic resin
portion is integrally formed with said metal plate by insert
molding said metal plate.
6. a throttle valve control apparatus of an internal combustion
engine as claimed in claim 1, wherein a rotation axis of said motor
is arranged in parallel to said throttle valve axis, wherein a
rotation of the rotation axis of said motor is transmitted to said
throttle valve axis via a reduction gear, and wherein a support
axis of an intermediate gear positioned at the midpoint of a torque
transmission path between the rotation axis of said motor and said
throttle valve axis.
7. A throttle valve control apparatus of an internal combustion
engine as claimed in claim 1, wherein said Hall element, and a
signal processing circuit converting an output of said Hall element
into a predetermined electric signal are attached to said
cover.
8. A throttle valve control apparatus of an internal combustion
engine as claimed in claim 1, wherein a spring holding said magnet
at a predetermined opening degree position at a time of shutting
off the current of said motor is installed to a periphery of said
throttle valve shaft.
9. A throttle valve control apparatus of an internal combustion
engine as claimed in claim 1, wherein said Hall element is
constituted by two elements arranged under a magnetic effect of
said magnet and backed up mutually.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a throttle valve control
apparatus for controlling a flow amount of intake air of an
internal combustion engine and a motor vehicle.
[0003] 2. Description of the Prior Art
[0004] An electrical control type throttle apparatus opening and
closing a throttle valve of an internal combustion engine by a
motor-driven actuator (for example, a direct current motor, a
stepping motor, a torque motor and a brushless motor) is put into
practice.
[0005] The electrical control type throttle apparatus is structured
such as to control an optimum throttle valve angle (throttle valve
opening degree) corresponding to an engine state on the basis of an
opening degree signal of an accelerator pedal and a traction
control signal. For this purpose, a sensor for detecting an angle
of the throttle valve, so-called a throttle sensor (which may be
sometimes called as an opening degree meter or a throttle position
sensor) is attached to a throttle body.
[0006] A potentiometer system is generally employed in the throttle
sensor, and a brush (a sliding element) rotating together with a
throttle valve shaft slides on a resisting body, thereby outputting
a potential difference signal (a sensor detecting signal)
corresponding to a throttle valve opening degree (for example,
refer to Japanese Unexamined Patent Publication No. 9-32588).
[0007] This kind of conventionally used throttle sensor is
structured such that the brush is in contact with a variable
resistance and a conductor formed on a resistance base plate so as
to slide thereon. Accordingly, a service life of the sensor is
short and the sensor is frequently in trouble. A double route of
sensor is employed so as to detect a trouble of sensor and mutually
back up, however, this can not basically solve the problem.
[0008] Further, since the trouble mentioned above is generated in
the conventional motor vehicle at a high possibility, and a control
parameter is controlled by an output of the sensor having a short
service life, an accuracy for operating and controlling the
internal combustion engine is low.
[0009] There has been known Japanese Patent No. 2845884 as a
structure for detecting the opening degree of the throttle valve in
a non-contact manner.
SUMMARY OF THE INVENTION
[0010] An object of the present invention is to provide a throttle
valve control apparatus provided with a throttle sensor which is in
trouble at a low possibility and has a long service life.
[0011] In particular, there is suggested some structures for
compactly attaching a non-contact type sensor to a throttle control
apparatus so as to constitute a part of the apparatus.
[0012] Further, there is suggested structures for removing a
magnetic noise and a bad influence against a magnetic
characteristic.
[0013] Further, another object is to improve a throttle sensor
corresponding to one of elements for controlling control parameters
of an internal combustion engine so as to improve an operation
control accuracy of the internal combustion engine.
[0014] In order to achieve the objects mentioned above, the present
invention proposes the following throttle valve control apparatuses
and motor vehicles.
[0015] In accordance with a first aspect of the present invention,
there is provided a throttle valve control apparatus of an internal
combustion engine comprising: [0016] a throttle valve axis rotated
by a motor-driven actuator; [0017] an alternate magnet mounted to
the throttle valve axis; [0018] a cover to which an element for
detecting a change of magnetic flux of the alternate magnet is
mounted; [0019] the cover being mounted to a throttle body to which
the motor-driven actuator is mounted; and [0020] an output of the
element constituting a function of an opening degree of the
throttle valve.
[0021] In accordance with a second aspect of the present invention,
there is provided a throttle valve control apparatus of an internal
combustion engine comprising: [0022] a throttle body provided with
a throttle valve controlling an amount of intake air; [0023] a
throttle sensor detecting a rotational angle of an axis to which
the throttle valve is mounted; and [0024] a motor-driven actuator
in which a command value is adjusted in accordance with an electric
signal output from the throttle sensor, [0025] wherein the throttle
sensor comprises: [0026] an element mounted to one end of the
throttle valve axis; and [0027] another element attached to a cover
member fixed to the throttle body so as to cover the axial end
portion, and [0028] wherein a magnetic physical amount between the
pair of elements is varied in accordance with a change of the
rotational angle of the throttle axis, and the element mounted to
the cover member outputs an electric signal relating to the
rotational angle of the axis in response to the change of the
magnetic physical amount.
[0029] In accordance with a third aspect of the present invention,
there is provided a motor vehicle comprising: [0030] an element
outputting an electric signal relating to an opening degree of a
throttle valve on the basis of a magnetic signal of a magnet
mounted to an axial end of the throttle valve, [0031] wherein a
control parameter of an engine is adjusted in accordance with a
change of the electric signal output from the element.
[0032] In accordance with a fourth aspect of the present invention,
there is provided a throttle control apparatus of an internal
combustion engine structured such as to transmit a rotation of a
motor to a throttle valve axis via a gear fixed to the throttle
valve axis, [0033] wherein a rotational angle of the throttle valve
axis is detected by a magnetic type throttle sensor comprising a
magnet and a hole element, and the gear is formed by a resin
material.
[0034] In accordance with a fifth aspect of the present invention,
there is provided a throttle valve control apparatus of an internal
combustion engine structured such that a rotary axis of a motor and
a throttle valve axis are arranged in parallel and a rotation of
the rotary axis of the motor is transmitted to the throttle valve
axis via a reduction gear, [0035] wherein a magnetic type throttle
sensor comprising a magnet and a hole element is mounted so as to
be capable of detecting a rotational angle of the throttle valve
axis, and [0036] wherein a rotary axis of a gear positioned in a
middle of a torque transmission path between the rotary axis of the
motor and the throttle valve axis is formed by a magnetic
material.
[0037] In accordance with a sixth aspect of the present invention,
there is provided a throttle valve control apparatus of an internal
combustion engine structured such as to detect a rotational angle
of a throttle valve driven by a motor, [0038] wherein a magnet is
mounted to the throttle valve axis; [0039] wherein hole elements
are arranged at positions facing to each other with respect to the
magnet and a stator corresponding to a magnetic path is attached
between the hole elements, and [0040] wherein the motor is mounted
to a position a uniform distance apart from the both hole
elements.
[0041] In accordance with a seventh aspect of the present
invention, there is provided a throttle valve control apparatus of
an internal combustion engine structured such that a sensor for
detecting a rotational angle of a throttle valve driven by a motor
is provided and a rotary axis of the motor and the throttle valve
axis are arranged in parallel, [0042] wherein a magnet is mounted
to the throttle valve axis, [0043] wherein hole elements are
arranged at positions facing to each other with respect to the
magnet and a stator corresponding to a magnetic path is attached
between the hole elements, and [0044] wherein the both hole
elements are arranged out of a circular arc having a radius
corresponding to a distance between the rotary axis of the motor
and a center of the throttle valve axis.
[0045] In accordance with an eighth aspect of the present
invention, there is provided a throttle valve control apparatus of
an internal combustion engine comprising: [0046] a magnet mounted
to a throttle valve axis to which a throttle valve is mounted; and
[0047] a cover fixed to a throttle body so as to cover the magnet
portion, [0048] wherein a hole element sensitive to a change of a
magnetic physical amount of the magnet and a signal processing
circuit converting an output of the hole element into a
predetermined electric signal are mounted to the cover.
[0049] In accordance with a ninth aspect of the present invention,
there is provided a throttle valve control apparatus of an internal
combustion engine structured such that a rotary axis of a motor and
a throttle valve axis are arranged in parallel and a rotation of
the rotary axis of the motor is transmitted to the throttle valve
axis via a reduction gear, [0050] wherein a cover is mounted to a
throttle body so as to cover the reduction gear, and [0051] wherein
a magnetic type throttle sensor comprising a magnet and a hole
element is mounted between an end surface of a gear fixed to the
throttle valve axis and the cover so as to be capable of detecting
a rotational angle of the throttle valve axis.
[0052] In accordance with a tenth aspect of the present invention,
there is provided a throttle valve control apparatus of an internal
combustion engine comprising: [0053] a magnet mounted to an end
portion of a throttle valve axis rotated by a motor; [0054] an
element detecting a rotational angle of the throttle valve axis in
cooperation with the magnet; and [0055] a spring holding the magnet
at a predetermined opening position of opening degree when
energizing of the motor is shut out, the spring being attached to a
periphery of the throttle valve axis.
[0056] In accordance with an eleventh aspect of the present
invention, there is provided a throttle valve control apparatus
comprising: [0057] a magnet mounted to a throttle valve axis
rotated by a motor; [0058] an element detecting a rotational angle
of the throttle valve axis in cooperation with the magnet; and
[0059] the element being constituted by two components arranged
under a magnetic influence of the magnet so as to be backed up by
each other.
BRIEF DESCRIPTION OF THE DRAWINGS
[0060] FIG. 1 is a cross sectional view of a throttle valve control
apparatus in accordance with an embodiment of the present
invention;
[0061] FIG. 2 is another cross sectional view of a throttle valve
control apparatus in accordance with an embodiment of the present
invention;
[0062] FIG. 3 is an exploded perspective view of a throttle valve
control apparatus in accordance with an embodiment of the present
invention;
[0063] FIG. 4 is an exploded perspective view of a throttle valve
control apparatus in accordance with an embodiment of the present
invention as seen from another angle;
[0064] FIG. 5 is a view for explaining a feature of a structure of
the embodiment;
[0065] FIG. 6 is a view showing a throttle valve axis assembly;
and
[0066] FIGS. 7A and 7B are views for explaining a positional
relation between a motion of a magnet and a hole element.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0067] A description will be given below of an embodiment in
accordance with the present invention with reference to the
accompanying drawings.
[0068] As shown in FIG. 1, an electronic control type throttle
valve apparatus (a throttle valve apparatus) is mainly constituted
by a throttle body (hereinafter, which may be simply called as a
body) 1, a throttle valve 4, a motor (a throttle valve drive
apparatus; a motor-driven actuator) 22 for driving the throttle
valve 4, a reduction gear mechanism 100, a sensor (a throttle
sensor) 80 measuring an opening angle (an opening degree) of the
throttle valve 4, that is, a rotational angle of the throttle valve
axis 3, and a cover 16 protecting the throttle valve axis 3, the
motor 22 and the reduction gear mechanism 100.
[0069] The body 1 is constituted by integrally forming a receiving
portion (an intake bore) 2 of the throttle valve 4 and a receiving
portion (a motor housing) 1c of the motor 22.
[0070] The throttle valve 4 is mounted to the throttle valve axis 3
by means of a screw 5, and the axis 3 is supported by bearings 6
and 26 provided in the body 1.
[0071] In accordance with the present embodiment, the bearing 6 is
formed as a ball bearing, and the bearing 26 is formed as a
cap-shaped plane bearing. The reason and details thereof will be
described later. The ball bearing 6 is attached to a bearing boss
1a via a seal ring 8. Further, an inner ring 6a of the ball bearing
6 is pressure inserted to an outer periphery of the throttle valve
axis 3, and an outer ring 6b is transition fitted to an inner
periphery of the bearing boss 1a.
[0072] In the throttle valve axis 3, only one end protrudes out of
a side wall of the body 1. Then, a spring 10, a lever 9, a spring
11 and a final stage gear (a driven gear) 12 of the reduction gear
mechanism 100 are attached to one end of the throttle valve axis
protruding out of the side wall.
[0073] Throttle valve relating parts (hereinafter, called as a
throttle valve mechanism) such as the throttle valve axis 3, the
reduction gear mechanism 100, the motor 22 and the like are
received in a receiving portion (a case) 1d formed on a side wall
of the body 1, and the receiving portion 1d is covered by a
synthetic resin cover 16. The plane bearing 26 is attached in
accordance with a pressure insertion.
[0074] That is, the throttle valve mechanism is arranged so as to
be protected by one cover 16, an opening (an opening for mounting
the motor) 1c' of a motor housing 1c is positioned so as to face
within the receiving portion 1d, the motor 22 is received in the
housing through the opening, and an end bracket 22a of the motor is
fixed in the periphery of the opening 1c' by a screw 37 (refer to
FIGS. 3 and 4).
[0075] A motor terminal 23 provided in the end bracket 22a is
positioned near one line of the side wall in the receiving portion
1d, is arranged so as to be directed to the cover 16 side, and is
connected to a relay terminal 24a provided in the cover 16 side via
a relay connector 33. The relay connector 33 can employ various
kinds of aspect. In the present embodiment, a sleeve made of a
conductive material is used as the relay connector 33, slits 34 and
35 having shifted directions at 90 degrees are provided in both
ends thereof, and the relay terminal 24a and the motor terminal 23
are inserted to the slit. The terminals 24a and 23 also have
shifted directions at 90 degrees in correspondence to the
directions of the slits 34 and 35.
[0076] The motor 22 is driven in response to an acceleration signal
relating to a pedaling amount of an acceleration pedal, a traction
signal, a uniform speed traveling signal, and an idle speed control
signal, and a power of the motor 22 is transmitted to the throttle
valve axis 3 via the reduction gear mechanism 100 (the motor pinion
21, middle gears 20 and the final stage gear 12). The pinion 21 is
mounted to a motor shaft 27, and the middle gears 20 are freely
fitted to a conductive shaft 19 adhered to the throttle body 1. A
gear 20a having a larger diameter among the middle gears 20 is
engaged with the pinion 21 and a gear 20b having a smaller diameter
is engaged with the gear 12.
[0077] The final stage gear 12 is a fan-shaped gear as shown in
FIGS. 3 and 4.
[0078] A description will be given of a relation between the gear
12 and the lever 9. The gear 12 has a hole 12h for passing one end
of the throttle valve axis 3 therethrough as shown in FIG. 3, the
hole 12h is formed in a shape capable of engaging with one end 3a
(having at least two flat surfaces) of the throttle valve axis and
is integrally rotated with the throttle valve axis.
[0079] The lever 9 is freely fitted to an outer periphery (a
circumferential surface) of the throttle valve axis 3, however, is
engaged so as to be together attracted to the gear via the spring
11. For example, a projection denotes by reference symbol 12f in
FIG. 4 is engaged with a projection (not shown) of the lever 9. The
projection 12f is formed inside the gear 12.
[0080] The spring 10 corresponds to a return spring for the
throttle valve, one end thereof is engaged with a spring engaging
portion (not shown) provided in the body 1, and another end thereof
is engaged with the lever 9.
[0081] The spring 10 applies a return force to the throttle valve
axis via the lever 9 and the gear 12, and further, constitutes a
so-called default opening degree setting mechanism which has been
already known, in cooperation with the spring 11 and the lever
9.
[0082] The default opening degree setting mechanism is structured
such as to keep an initial opening degree of the throttle valve 4
at a time of turning off an engine key (in other words, at a time
when the motor-driven actuator 22 is not energized) to a
predetermined opening degree larger than a full close position.
[0083] Between the default opening degree position to a full open
control position, the throttle valve opening degree is determined
in correspondence with a balance between a torque of the motor 22
and a valve closing force of the spring (the return spring) 10.
[0084] In the case of controlling so as to make the throttle valve
opening degree smaller than the default opening degree, a motion of
the lever 9 is restricted by a default opening degree stopper (not
shown) and the control operation is performed by rotating only the
gear 12 and the throttle valve axis 3 in a full closing direction
against the force of the spring 11.
[0085] A movable side stopper 12d provided in one line of the
fan-shaped gear 12 is brought into contact with a full close
stopper (not shown) for restricting a mechanical full close
position of the throttle valve, whereby a full close position is
determined.
[0086] With respect to a material of the gear 12 in accordance with
the present embodiment, a center portion thereof is formed by a
metal plate 12a, and a portion 12b forming teeth and the other
portions are integrally formed by a synthetic resin (a reinforced
plastic).
[0087] In this case, the metal plate 12a is insert molded to the
resin portion of the gear 12.
[0088] A side end of the gear 12 of the magnet 82 faces to the
resin portion of the gear.
[0089] Accordingly, it is possible to prevent a magnetic flux of
the magnet 82 from being leaked to the gear 12.
[0090] The metal plate 12a in a center portion of the gear 12 is
pressed to the throttle body 1a side by a magnet holder 81,
however, since the magnet holder 81 itself is made of a resin, the
magnetic field is not leaked even if the magnet holder 81 is in
contact with the metal plate 12a.
[0091] The movable side stopper 12d formed in one of cut end
surfaces of the gear 12 is integrally connected to the metal plate
12a.
[0092] The movable side stopper 12d is made of a metal for the
purpose of achieving an abrasion resistance, and an impact
resistance. That is, mechanical full close position of the throttle
valve becomes a reference point on control, and the stopper element
12d is brought into contact with the full close stopper 25 in a
fixed side at least one time at every operation starting times or
operation finishing times. Accordingly, the movable side stopper
12d is made of a metal so as to resist against a comparatively high
collision frequency.
[0093] Reference symbol 12i denotes a guide for engaging the gear
12 with the lever 9.
[0094] The resin magnet holder 81 is pressure inserted and fixed to
the front end of the throttle valve axis 3, and the magnet 82 is
integrally attached to the magnet holder 81 in accordance with a
molding process.
[0095] An end portion of the magnet holder 81 presses the end
surface of the gear 12 to a stepped portion 3d side of the throttle
shaft 3, and commonly serves to prevent the gear 12 from being
taken out.
[0096] A circuit board 84 of the throttle sensor 80 is fixed to a
position opposing to the end portion of the throttle axis 3 on the
inner surface of the cover 16 by a welding pin 86.
[0097] A pair of semicircular stators 83 are fixed to the circuit
board 84 so as to surround a periphery of the magnet 82 in such a
manner as to face to each other with keeping a predetermined
interval 87. Reference numeral 85 denotes a guide of the stator 83
integrally provided in the circuit board 84.
[0098] Hole elements 86 are mounted to a gap 87 portion between a
pair of semicircular stators 83.
[0099] Three terminals of the hole elements 86 are mechanically
held to the circuit board 84 and are connected to a signal
processing circuit such as an amplifier or an analogue/digital
converter (not shown) arranged in the circuit board 84.
[0100] The signal processing circuit arranged in the circuit board
84 is connected to a conductor 24 integrally molded with the cover
16, and can transmit a signal to an external apparatus via an
electric terminal 40 (connected to the conductor 24) of the
connector 16b integrally formed with the cover.
[0101] The hole element 86 detects a change of the magnetic field
and generates a hole voltage when the throttle valve axis 3 rotates
and the magnet 82 rotates.
[0102] The voltage is transmitted to the external circuit via the
conductor 24 and the terminal 40 after being amplified by the
amplifier or signal converted (including an amplification) by the
analogue/digital converter.
[0103] An engine control unit (not shown) of a motor vehicle is
provided with a coupler connected to the connector 16b and a signal
line, and the signal from the terminal 40 is input to the control
unit.
[0104] The control unit corrects a fuel and an opening degree of a
throttle valve corresponding to the control parameters and controls
a speed change point of an automatic transmission, on the basis of
a throttle opening degree and a vehicle speed detected in
correspondence to a change of magnetic field corresponding to a
magnetic physical amount of the magnet 82.
[0105] Further, the spring 11 urges the gear 12 in a throttle valve
opening direction so as to forcibly open the magnet 82 of the
sensor to a predetermined opening degree position, when the
energizing of the motor 12 is shut out.
[0106] Accordingly, in the motor vehicle provided with the throttle
control apparatus in accordance with the present embodiment, the
control parameters of the engine are adjusted in correspondence to
the change of the electric signal which the hole element 86 outputs
in connection with the opening degree of the throttle valve in
response to the magnetic signal of the magnet mounted to the axial
end of the throttle valve.
[0107] Since the sensor is a non-contact type, the opening signal
of the throttle valve 4 corresponding to the change of the electric
signal which the hole element 86 outputs is not exposed to a
secular change so much, so the it is possible to accurately adjust
the control parameters of the internal combustion engine for a long
period.
[0108] A description will be given of a principle of the sensor
with reference to FIG. 7.
[0109] The magnet 82 corresponding to a rotor of the throttle
sensor 80 is fixed to the magnet holder 81 in a state of facing a
pair of arc-shaped magnets mutually having different polarities to
each other.
[0110] When the magnet holder 81 is fixed to the throttle valve 3
and the throttle valve axis 3 is rotated, bonding surfaces of both
of the magnets are relatively rotated with respect to the hole
element. FIG. 7 shows a change of a magnetic line of force in this
state.
[0111] A pair of hole elements 86 placed in the bonding surface
portion of the magnetic pole output a signal forming a function of
a rotational angle in response to the change of the magnetic line
of force generated in correspondence to the change of the
rotational angle of the throttle valve axis 3.
[0112] Since the gear 12 is made of a synthetic resin, the magnetic
field generated by the magnet 82 is not badly influenced by the
gear 12.
[0113] In the embodiment, the center portion fitted to the throttle
valve axis 3 is made of a metal, however, a magnetic bad influence
is further reduced by forming all the elements by a synthetic
resin.
[0114] Since the magnetic field is not shifted even when the shape
of the gear 12 is an irregular shape such as a fan shape, a
sensitive characteristic of the hole element 86 can be uniformly
obtained without relation to an angle of rotation of the throttle
axis.
[0115] As shown in FIG. 5, the hole element 86 is mounted in an
outer portion of an area of a circular arc S drawn around a center
of rotation of the motor by setting a size between a center of the
rotary axis of the motor and a center of rotation of the throttle
to a radius.
[0116] As a result, the hole element 86 is hard to be affected by
an electromagnetic influence caused by a change of a drive current
of the motor, and a detecting accuracy of the hole element 86 is
hard to be deteriorated.
[0117] Since the structure is made such that the stator 83 is
mounted to the circuit board 84 so as to be fixed to the inner
surface of the cover 16, an assembling operation of the stator 83
can be easily performed.
[0118] In this case, it is possible to directly fix the stator to
the cover 16.
[0119] In this case, the stator is fixed with shifting the control
circuit from the stator, however, there is an advantage that a size
in an axial direction can be shortened.
[0120] Since the rotational support axis 19 of the middle gear 20
positioned between the motor 22 and the magnetic type non-contact
sensor 80 is made of a magnetic material, it is possible to expect
an effect of shielding an electromagnetic influence caused by the
change of the drive current of the motor 22 by the rotational
support axis 19, so that the hole element 86 is hard to be affected
by the electromagnetic influence of the motor 22, and a detecting
accuracy of the hole element 86 is hard to be deteriorated.
[0121] As shown in FIG. 6, since it is possible to assemble the
throttle valve axis 3, the springs 10 and 11, the lever 9, the
final stage gear 12, the magnet holder 81 and the magnet 82 to the
throttle body 1 as a sub-assembly, an assembling operation can be
easily performed.
[0122] In accordance with the present invention, it is possible to
assemble the non-contact type sensor in the throttle body in a
compact manner.
[0123] In accordance with another invention, it is possible to
arrange the non-contact type throttle sensor between the cover of
the throttle body and the gear in a compact manner.
[0124] Further, in accordance with the other invention, it is
possible to assemble the non-contact type throttle sensor of the
electromagnetic system in the throttle body by the structure which
is hard to be affected by the electromagnetic noise.
[0125] Since it is possible to adjust the control parameters of the
engine on the basis of the throttle opening degree signal which has
a little secular change, a motor vehicle having a high control
accuracy can be obtained.
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