The present application claims priority from Japanese application serial no. 2003-390259, filed on Nov. 20, 2003), the content of which is hereby incorporated by reference into this application.
The present invention relates to an electronically controlled throttle device, which electrically controls intake air flow into an in-vehicle engine.
Generally, the internal combustion engines for vehicles employ an electronically controlled throttle device which adjusts intake air flow by controlling a throttle valve opening by an actuator such as DC motor. The electronically controlled throttle device moves a position of the throttle valve by the actuator so as to be reach to a target opening which is calculated by an amount of accelerator pedal depression and operating status of the engine. The throttle valve opening is detected by a valve position sensor, and then a feed back control carries out.
The electronically controlled throttle device has a housing member (housing section) for the throttle valve and a housing member (housing section) for the valve drive motor, which are integrally molded, and a DC motor is put in the motor housing member. Furthermore, the throttle body is provided with a power transmission unit which transmits a driving power from the DC motor to the throttle valve, and a cover is mounted on the throttle body to protect the DC motor and the power transmission unit.
The DC motor is controlled by pulse signals from an H-bridge circuit, which is obtained by arranging switching elements in H-shape. A control amount according to a deviation between an actual opening and the target opening of the throttle valve is subjected to PID compensation calculation, converting the amount into a duty ratio, which is a ratio between ON time and OFF time, and then the ON/OFF control is carried out on the switching elements constituting the H-bridge circuit, by throttle device signals (throttle device-width modulation signals: PWM signals).
There are types of electronically controlled throttle body, i.e., in one type, an electronic control module for carrying out ON/OFF driving of the DC motor according to an opening deviation is installed on the throttle body cover, and in another type, the electronically control module is installed on an external engine control unit. The former is described, for example, in the following Patent Document 1.
In the meantime, when the DC motor is controlled by the pulse signals, a radiant noise may occur on startup of the switching operation and at the falling edge thereof. The radiation noise may cause a radio noise and the like. A general countermeasure against the radiant noise is based on a slew rate control, which carries out a control to make the startup slope and falling slope less steep. However, it is difficult to completely remove a noise which is generated from the DC motor itself of the electronic controlled throttle body, and a noise radiated from a wire harness (signal line) which connects the electronic controlled throttle body and the control unit. Therefore, those noises are radiated in FM radio frequency band and the like, thereby making a sound from the radio unclear.
In order to solve the problem above, an inductance is mounted between motor terminals for electrically connecting a brush of the DC motor and an external area, that is, inside the DC motor. The inductance is mounted not only to make down a slope of a large amount of current which flows in a moment, at startup and braking, but also to remove a noise. It is to be noted here that the inductance is set to be a value to the extent of not affecting a performance in response.
In the conventional art, the inductance is mounted inside the DC motor. However, a dimension of the inductance is determined based on a regulation by a coil diameter, according to a permissible current value specification and the maximum current specification at the time of using the electronic controlled throttle body. Particularly, in recent years, PWM signal frequency becomes higher, a noise level being increased, and thus a capacity of the inductance has to be enlarged. For this reason, the DC motor cannot be downsized, and further there is a problem of high-cost because environmental temperature specification of the inductance is made stricter due to self-heating of the DC motor. In addition, there is a practical problem that due to the heat of the DC motor, performance of field magnet (permanent magnet) is deteriorated, thereby reducing reliability.
An object of the present invention is to provide an electronically controlled throttle device, in which the DC motor can be downsized and made less expensive, as well as enhancing reliability and reducing the radiant noise.
The subject matter of the present invention is as follows.
A throttle body is configured with a throttle valve housing section and a motor housing section which are integrally molded. A DC motor is put in the motor housing section of the throttle body to drive the throttle valve. A power transmission unit is arranged on the throttle body to transmit a driving power from the DC motor to the throttle valve. A cover is attached on the throttle body to protect the DC motor and the power transmission unit. An inductance(s) is (are) installed on an inner surface of the cover and connected with the DC motor and a power supply through conductors.
Specifically, each one end of the conductors varied in the cover is allowed to protrude neat to the inductance on the inner surface of the cover. Such protruding ends of the conductors function as holder to hold both ends of the inductance.
The present invention is provided with the inductance, which is to remove a radiant noise, on the inner surface of the cover attached on the throttle body. Thus the DC motor as throttle drive motor can be downsized and made less expensive, as well as there is no more influence due to the heat of the DC motor, it is possible to enhance reliability and to reduce the radiant noise.
A throttle body is configured with an external wall section for a gear space, a throttle valve housing section and a motor housing section which are integrally molded with an insulating material. A DC motor is put in the motor housing section of the throttle body. A power transmission unit is configured with gears which are arranged on the external wall section of the throttle body, and transmits a driving power from the DC motor to the throttle valve. A cover is attached on the external wall section, so it covers the DC motor and the power transmission unit. A connector, which is electrically connected with an external unit, is provided on an outer surface of the cover. The connector has a plurality of terminals including two power supply terminals for the DC motor. An electronic control module is placed in a module housing section provided at the cover to control said throttle valve. The electronic control module has two motor driving terminals, and is connected to the power supply terminal of the connector through an conductor buried in the cover. The electronic control module controls an opening degree of the throttle valve by driving the DC motor by electrical throttle devices. On the inner surface of the cover, an intermediate connector with joint members is provided, which has two terminals. The intermediate connector is connected to terminals of DC motor side through the joint member when the cover is attached on the external wall section of the throttle body. Two inductances constituting a noise eliminator are placed in parallel near to the module housing section on inner surface of the cover. One end of each inductance is connected with each motor driving terminal of the electronic control module through one conductor buried in the cover. Another end of each inductance is connected with each terminal of the intermediate connector through another conductor buried in the cover. Each one end of the conductors protrudes near to the inductances on the inner surface of the cover. Such protruding ends of the conductors hold both ends of the inductances. The inductances are covered by gel.
In
In
In the throttle body 1, as shown in
As shown in
As shown in
In the body 1, as shown in
As thus described, the power transmission unit 4 for transmitting the driving power from the DC motor 3 to the throttle valve 2, the DC motor serving as a throttle valve driving unit, is integrally built in the body 1.
A cover 40 for protecting the throttle valve 2, the DC motor 3, and the power transmission unit (gear mechanism) 4 is molded with an insulating material such as resin. As shown in
The cover 40 is attached on the external wall section 12 so that it covers the upper surface 12a of the external wall section 12 of the body 1, in order to protect throttle valve mechanism comprising the valve shaft 8, the deceleration gear mechanism 4, the DC motor 3, and the like. The DC motor 3 and the deceleration gear mechanism (power transmission unit) 4 are arranged so that they are protected by the cover 40 as one piece. As shown in
A motor terminal 33 of the DC motor 3 is provided on this end bracket 3a near to the motor shaft 32. Two terminals are arranged adjacent to one side of the rim (frame) 30 formed on the upper surface 12a of the external wall section, in such a manner as facing upwardly, that is, facing to the cover 40 side. The motor 3 is driven by pulse signals in accordance with an accelerator signal relating to a depression amount of the acceleration pedal and a traction control signal, and the driving power from the DC motor 3 is transmitted to the valve shaft 8 via the gears 5, 6a, 6b, and 9.
The fan-like gear 9 is fixed on the valve shaft 8, and it is engaged with the lever 24 in such a manner as attracting each other via the spring 25, the lever 24 rotatably putting on the valve shaft 8. Consequently, the lever 24 is capable of rotating with the valve shaft 8 up to about 90 degrees. The spring 23 is a return spring of the throttle valve 2, and one end is locked on the spring lock part 85 provided on the body 1, and the other free end is locked on the lever 24.
The springs 23, 25 and the lever 24 constitute a default opening setting mechanism that is well known. The default opening setting mechanism holds an initial opening of the throttle valve 2 which opens more than a full closed position, at the time of engine key off (at the time when the DC motor 3 is stopped). From the default opening position to a full-throttle (full opening) control position, the throttle vale opening is determined based on a balance between the driving power from the DC motor 3 and the force of the spring (return spring) 23. When the throttle valve opening is controlled less than the default opening, movement of the lever 24 is restricted by the default opening stopper (not illustrated), and only the gear 9 and the valve shaft 8 can turns up to the full closed position against the force from the spring 25. A stopper 86 is provided for defining the full closed position, and the full closed position is determined when one side of the fan-like gear 9 comes into contact with the stopper.
The cover 40 is formed in substantially rectangular shape in plan view, similar to an outline of the external wall section 12. In the same manner as the external wall section 12, one edge is notched in “dogleg shape”. A flange 41 is formed on all over the periphery of the cover 40. As shown in
The both housings section 40A and 40B and the intermediate connector 42 are adjacently arranged allowing for compact storage inside the cover 40. The sensor housing 40A is arranged on one side and the intermediate connector 42 is arranged on the other side, placing the module housing 40B therebetween.
The cover 40 is integrally molded with insulating material such as synthetic resin.
Electric wires (conductors) 44 are buried by molding in the cover 40, to connect between the connector 43 for external connection and the electronic control module 11, and between the electronic control module 11 and the intermediate connector 42.
Two inductances 45a and 45b are installed adjacent to each other in parallel in an inductance installation section 40C lo which is formed at a part of an inner surface of the cover 40. The inductance installation section 40C is provided in the vicinity of the module housing 40B. As shown in
A groove is formed on the top of each holder 44a. After the both ends of each inductance 45 are put in the groove, the holder is pressed, thus the inductance is firmly secured.
Furthermore, a plurality of lead frames 50 are buried and orderly arranged on the cover 40, so as to realize connection with a plurality of terminals 51 on a substrate mounting the electronic control module 11. Ends in one side of the lead frames 50 are exposed at a position adjacent to one side of the module housing 40B on the inner surface of the cover 40, and the other ends form connector pins 43a of the connector 43 for external connection as shown in
The connector 43 for external connection is connected to a cable connector on the engine control unit (not illustrated) side, and connector pins 43a configure various input terminals and output terminals. For example, as the input terminals, there are terminals for a battery power supply and for inputting output signals from the engine control unit (communication signal, cruise control signal, vehicle velocity signal, acceleration pedal signal, and the like). And as the output terminals, there are signals for a throttle valve opening signal, a communication signal from the electronic control module 11 to the engine control unit, and the like. Two of the connector pins 43a serve as power supply terminals to drive the DC motor 3.
As shown in
The top of the module housing 40B is covered with a module cover 54. The module cover 54 is installed by adhesive joining on the side wall of the cover 40 which forms the module housing 40B. A circular projection 54a is formed integrally on the module cover 54 by molding, and it prevents the gears 6a, 6b from coming out from the gear shaft 34 in the axial direction. The circular projection 54a is provided on a surface opposite to the adhered position of a module cover 54 on inner surface of the cover 40.
The intermediate connector 42 is integrally molded with the cover 40 on the inner surface of the side wall 49 of the cover 40. Motor connection terminals 15 as shown in
As shown in
The electric wire conductor 44 connected to one end of the inductance 45a, which is installed adjacently on the inner surface of the cover 40, is also connected to the motor drive terminal 17a of the electronic control module 11 through the wire bonding 18. Furthermore, the electric wire conductor 44 connected to one end of the inductance 45b is also connected to the motor drive terminal 17b of the electronic control module 11 via through the wire bonding 18. The inductances 45a and 45b constitute a noise eliminator and one ends of them are connected to the motor drive terminals 17a and 17b of the electronic control module 11 through the electric wire conductor 44.
The motor drive terminals 17a and 17b of the electronic control module 11 are output terminals of the H-bridge circuit which arranges switching elements in H-shape. Therefore, the DC motor 3 is driven by pulse signals.
Inside the four corners of the flange 41 of the cover 40, holes 55 for cover attachment are drilled, and those holes are aligned with holes 27 of the throttle body 1 and screwed as shown in
As described above, an electronic control module 11 is installed on the inner surface of the cover 40, further the connector 43 for external connection is provided on the outer surface of the cover 40, and a group of lead frames 50 constituting the terminal of the connector are molded and buried. In addition, ends in one side of the group of the lead frames 50 are orderly arranged along one edge inside the cover 40. It is possible to connect the group of lead frames 50 with a group of terminals 51 of a print circuit board mounting the electronic control module 11, without spreading the group of lead frames 50 within the cover 40.
Power supplying from the DC motor 3 is carried out through the connector 43 for external connection, the electronic control module 11, the inductance 45 installed on the cover 40, and the intermediate connector 42 provided on the cover 40. Therefore, it is not necessary for the lead frames of the power supply to spread in the cover 40, and electric wiring can be rationalized (reduction of wiring and facilitation of connection works can be achieved).
The valve position sensor 7 is a packaged unit type, and assembled in advance as one assembly as shown in
As shown in
When the cover 40 is attached on the throttle body 1, the upper end of the valve shaft 8 is inserted into the hole 72 while the elastic piece 80 deforms elastically by pushing of the insertion. The rotor 79 goes into engagement with the valve shaft 8 without rattling by a fastening force from the circular spring 81.
As shown in
The partitioning wall 58 at the notch 59 is protruding to some extent. On the other hand, as shown in
The electronic controlled throttle system according to the present invention is configured as described above. In here the inductance is installed on the inner surface of the cover which is attached on the throttle body in order to protect the DC motor and the power transmission unit disposed on the throttle body, the inductance being connected to the DC motor and the driving power source through the electric wire conductor. Therefore, the DC motor can be downsized and made less expensive, as well as there is no more influence due to the heat of the DC motor, it is possible to enhance reliability and to reduce the radiant noise.
In the above embodiment, since the inductance is installed with the holder members (supporting legs) which are formed by allowing each one end of the electric wire conductors buried to protrude and expose on the inner surface the cover, it is easy to install the inductance on the cover. Further, the end of the holder members by the electric wire conductors serves as a stopper to prevent the inductance from dropping off, and thus it is not necessary to use an expensive adhesive material which is resistant to high temperature circumstance. In other words, it is possible to mount a low-cost inductance.
Another embodiment of the present invention is shown in
An inductance housing 92 is formed on the cover 90 by the partitioning wall 91. In the inductance housing 92, the inductances 45a and 45b are installed on the holder members (supporting legs 44a) formed by the electric wire conductors 44, as shown in
The electric wire conductors 44 connected to ends on one side of the inductances 45a and 45b are respectively connected to two connector pins 43a of the connectors for external connection 43. The two connector pins 43a connected with the electric wire conductors 44, serve as driving power terminals to which a motor driving power source from the electric control module, provided in the engine control unit, is applied. The inductances 45a and 45b constitute a noise eliminator, and one end thereof is connected to the driving power source terminal of the connector for external connection 43, through the electric wire conductor 44.
The electric wire conductors connected to the other ends of the two inductances 45a and 45b are connected to the terminal 15 of the intermediate connector 42 (exposed end portion 15A) similar to the example 1. The other ends of the inductances 45a and 45b are connected to the motor terminal 33, that is, the DC motor 3, through the electric wire conductor 44. Both ends of the armature of the DC motor 3 are connected to the inductance 45.
It is to be noted that on the inner surface of the cover 90, there is formed a circular projection 93 for regulating the gears 6a and 6b integrally molded not to deviate from the gear shaft 34 into the axial direction.
As described above, also in the example 2, since the inductance for removing a radiant noise is installed on the inner surface of the cover, which is mounted on the throttle body, the DC motor can be downsized and made less expensive, as well as there is no more influence due to the heat of the DC motor, it is possible to enhance a reliability and to reduce the radiant noise.
In the above examples 1 and 2, two inductances are provided but it is matter of course that only one inductance is also applicable.
Number | Date | Country | Kind |
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2003-390259 | Nov 2003 | JP | national |