JP2006207598A - Throttle valve driving device of engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To give predetermined low speed opening to a throttle valve even when an electric motor cannot carry current completely, prevent engine stalling, and enable start of an engine and minute speed running of a vehicle at cold time. <P>SOLUTION: A stopper plate 30 energized in the direction of closing of the throttle valve 2 by a return spring 33 is rotatably fitted into a valve shaft 3 of the throttle valve 2 driven by the electric motor 4. When the electric motor 4 cannot carry current and the stopper plate 30 rotates by return by force of the return spring 33, it rotates the valve shaft 3 in the direction of closing of the throttle valve 4 through an engaging means 36, but prevents return-rotation of the stopper plate 30 by a stopper bolt 34 when the throttle valve 2 reaches predetermined low speed opening, for example, a fast idle opening position. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an engine throttle valve driving device in which an electric motor such as a step motor capable of opening and closing the throttle valve is connected to an engine throttle valve.

Such a throttle valve driving device is already known as disclosed in Patent Document 1.
Japanese Patent Laid-Open No. 6-213012

  By the way, in the throttle valve driving device disclosed in Patent Document 1, even when one of the first and second excitation circuits of the step motor fails, the throttle valve is operated by energizing the other normal excitation circuit. It opens with a small opening to prevent engine stall. However, even if the energization of both the first and second excitation circuits becomes impossible for some reason, the throttle valve is closed to the fully closed position by the resilient force of the return spring, so that the engine stall cannot be avoided. .

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide the throttle valve driving device capable of preventing the engine stall by opening the throttle valve to a predetermined opening even when the electric motor cannot be energized. And

  In order to achieve the above object, the present invention provides an engine throttle valve drive apparatus in which an electric motor capable of opening and closing the engine is connected to a throttle valve of the engine. When the stopper plate rotates in the closing direction of the throttle valve relative to the valve shaft, an engagement means is provided between the fitting stopper plate and the stopper plate to connect the valve shaft and the stopper plate. A return spring for biasing the throttle valve in the closing direction of the throttle valve is connected, and stopper means for preventing return rotation by the return spring of the stopper plate at a position corresponding to a predetermined opening that can prevent the throttle valve from being stalled. On the other hand, the first feature is that the valve shaft is connected with an auxiliary spring that urges the valve shaft in the opening direction of the throttle valve with a spring force weaker than that of the return spring.

  In addition to the first feature, the second feature of the present invention is that the predetermined opening of the throttle valve is a low-speed opening that allows the vehicle to travel at a very low speed.

  In addition to the first feature of the present invention, the detection shaft of the throttle sensor is connected to the valve shaft via a joint, and the detection shaft is rotated in the rotational direction by the spring force of the auxiliary spring to eliminate backlash of the joint. The third feature is that the power is energized.

  According to the first aspect of the present invention, the throttle valve can be held at an open position with a predetermined opening that can prevent engine stall even when the electric motor cannot be energized during engine operation, thereby preventing engine stall. can do. Further, even when the engine is stopped, the throttle valve is kept in the open position in the same manner as described above, so that the sticking of the throttle valve due to the accumulation of carbides or the like in the blowby gas can be prevented.

  Further, according to the second feature of the present invention, even when the electric motor cannot be energized, the throttle valve can be held in the open position of the low speed opening, not only preventing the engine stall but also allowing the vehicle to travel at a low speed. The engine can also be started cold.

  Further, according to the third feature of the present invention, the auxiliary spring also serves as a spring for removing backlash of the joint connecting the valve shaft and the detection shaft, thereby improving the detection accuracy of the throttle sensor and simplifying the structure. Can be achieved.

  Embodiments of the present invention will be described below on the basis of preferred embodiments of the present invention shown in the accompanying drawings.

  1 and 2, a throttle body 1 connected to an inlet end of an intake manifold M mounted on an automobile has a valve shaft 3 of a butterfly throttle valve 2 that opens and closes an intake passage 1a. 7 and 7 are rotatably supported.

  A step motor 4 as an electric motor is mounted on the left side surface of the throttle body 1 with its output shaft 5 arranged coaxially with the valve shaft 3, and the output shaft 5 and the valve shaft 3 are connected via a lost motion mechanism 6. The

  The lost motion mechanism 6 includes a drive plate 8 and a driven plate 9 fixed to opposite ends of the output shaft 5 and the valve shaft 3, respectively. The driving and driven plates 8 and 9 are formed with engaging pieces 10 and 11 that are opposed to each other along the circumferential direction thereof. On the other hand, they are arranged so as to contact each other when they rotate in the opening direction of the throttle valve 2. The driving and driven plates 8 and 9 are connected to a connecting spring 12 that biases them in the contact direction of the engagement pieces 10 and 11. Furthermore, a stopper piece 13 is formed on the driven plate 9, and a stopper bolt 14 that abuts against the stopper piece 13 and defines a fully closed position S (see FIG. 3) of the throttle valve 2 is screwed onto the throttle body 1. Worn.

  Therefore, when the step motor 4 is operated in the opening direction of the throttle valve 2 (forward rotation direction), the drive plate 8 driven by the output shaft 5 brings the engagement pieces 10 and 11 into contact with each other to bring the driven plate 9 into contact. Driven in the forward direction, the throttle valve 2 can be opened via the valve shaft 3. Further, when the step motor 4 is operated in the closing direction (reverse direction) of the throttle valve 2, the drive plate 8 can drive the driven plate 9 in the reverse direction via the connecting spring 12 to close the throttle valve 2. In this case, when the throttle valve 2 reaches the predetermined fully closed position S, the stopper piece 13 of the driven plate 9 abuts against the first stopper bolt 14, and the reverse rotation of the step motor 4 thereafter is performed by both engagement pieces. The connecting spring 12 is deformed while separating the distances 10 and 11, thereby preventing an excessive closing torque from being applied to the throttle valve 2.

  The step motor 4 is a known motor as disclosed in Japanese Patent Laid-Open No. 6-213012, and includes first and second excitation circuits 16 and 17. The first excitation circuit 16 has a first phase a that is energized in the forward direction and a third phase c that is energized in the reverse direction, and the second excitation circuit 17 is a second phase that is energized in the forward direction. Phase b and a fourth phase d energized in the opposite direction. Energization of these first to fourth phases a to d is controlled by the electronic control unit 15.

  Thus, the electronic control unit 15 performs simultaneous energization of the first and second phases a and b, simultaneous energization of the second and third phases b and c, simultaneous energization of the third and fourth phases c and d, The rotor shaft of the step motor 4, that is, the output shaft 5 can be rotated to a certain angle by operating so as to sequentially repeat the simultaneous energization of the fourth and first phases d and a.

  A throttle sensor 20 is mounted on the right side surface of the throttle body 1 with its detection shaft 21 arranged coaxially with the valve shaft 3, and the valve shaft 3 and the detection shaft 21 are connected via a joint 22. The joint 22 includes a joint plate 23 fixed to the right end of the valve shaft 3 and a joint pin 24 fixed to the left end of the detection shaft 21 and extending in the radial direction. A fork 25 sandwiched in the circumferential direction of the detection shaft 21 is formed.

  Therefore, the opening change of the throttle valve 2 is transmitted from the valve shaft 3 to the detection shaft 21 via the joint 22. When the throttle sensor 20 detects the opening of the throttle valve 2 in this way, a signal corresponding to this is output to the electronic control unit 15.

  A boss 30a of the stopper plate 30 is rotatably fitted to the right end portion of the valve shaft 3 adjacent to the joint plate 23. The joint plate 23 and the stopper plate 30 are formed with engaging pieces 31 and 32 that are opposed to each other along the circumferential direction thereof. The engaging pieces 31 and 32 are connected to the stopper plate 30 by the joint plate 23. On the other hand, when rotating in the opening direction of the throttle valve 2 relatively, they are arranged so as to contact each other. These engagement pieces 31 and 32 constitute an engagement means 36 for connecting the stopper plate 30 and the valve shaft 3 in a constant rotational direction.

  The stopper plate 30 is connected to a return spring 23 that urges the stopper plate 30 in the closing direction of the throttle valve 2. Thus, the elastic force of the return spring 23 acts to close the throttle valve 2 from the stopper plate 30 to the valve shaft 3 via the joint plate 23.

The engagement piece 32 of the stopper plate 30 is opposed to a second stopper bolt 34 (stopper means) that abuts against the engagement piece 32 and defines a return rotation limit by the return spring 33 of the stopper plate 30. The bolt 34 is screwed to the throttle body 1. By defining the rotation limit of the stopper plate 30 by the second stopper bolt 34, the throttle valve 2 is given a predetermined opening that can prevent engine stall, for example, a small opening θ ₁ or a low opening θ ₂ ( (See FIG. 3). Here, the minute opening θ ₁ is an idle opening that can ensure a normal idling state of the engine, for example, about 1 ° (engine speed is around 1,000 rpm), and the low opening θ ₂ is Even when the engine is started, a fast idle opening that allows the vehicle to start at a low speed, for example, about 2.5 ° (about 2,000 rpm at the engine speed).

  Further, the detection shaft 21 is equipped with an auxiliary spring 35 that urges the detection shaft 21 in the opening direction of the throttle valve 2. The spring force of the auxiliary spring 35 is weaker than that of the return spring 33, but is set stronger than the detent torque of the step motor 4. Moreover, the spring force removes the backlash of the joint 22 and acts so that the engaging pieces 31 and 32 are always brought into contact with each other.

  In addition to the throttle sensor 20, the electronic control unit 15 includes a boost sensor 37 that detects the boost pressure of the engine, an accelerator sensor 38 that detects the amount of operation of an accelerator operator such as an accelerator pedal, and the engine speed. An output signal from the engine rotation sensor 39 or the like is input.

  Next, the operation of this embodiment will be described.

  For example, when the accelerator pedal is depressed in order to accelerate the rotation of the engine during the operation of the automobile, the electronic control unit 15 operates the step motor 4 based on the output signal of the accelerator sensor 38 corresponding to the depression amount, and the throttle valve Open 2 The opening degree of the throttle valve 2 is detected by the throttle sensor 20, the change of the engine speed is detected by the engine speed sensor 39, the boost pressure is detected by the boost sensor 37, and a signal corresponding to each detected amount is sent to the electronic control unit. 15 is input. Therefore, the electronic control unit 15 corrects the operation amount of the step motor 4 based on these input signals so that the engine speed and the boost pressure match the depression amount of the accelerator pedal.

  By the way, when the throttle valve 2 is opened at a high degree of opening, either one or both of the first excitation circuit 16 and the second excitation circuit 17 of the step motor 4 cannot be energized due to some failure. Then, since the elastic force of the return spring 33 acts on the valve shaft 3 in the closing direction of the throttle valve 2 via the stopper plate 30 and the joint plate 23, the throttle valve 2 starts to close by the elastic force, and the stopper plate When the 30 engagement pieces 32 abut against the second stopper bolt 34, the closing operation stops.

  That is, when the engaging piece 32 of the stopper plate 30 abuts against the second stopper bolt 34, the closing force of the return spring 33 does not act on the throttle valve 2, but the throttle valve 2 is attached to the detection shaft 21. Since the spring force of the auxiliary spring 35 that is weaker than the return spring 33 and stronger than the detent torque of the step motor 4 is always acting in the opening direction, the spring force of the auxiliary spring 35 causes the joint plate 23 and the stopper plate 30 to move. By holding both engagement pieces 31 and 32 in contact with each other, the closing operation of the throttle valve 2 is stopped and blind movement at that position is suppressed.

At this time, engine stall if the opening degree of the throttle valve 2 is it is set to the minute opening theta ₁ is avoided, also if it is set to the low speed opening theta _2, engine stall does not occur only one, of the vehicle In addition to being able to run at a low speed, the engine can be cold-started after the engine is stopped.

  The spring force of the auxiliary spring 35 that urges the valve shaft 3 in the opening direction of the throttle valve 2 is extremely weak. Therefore, when both the excitation circuits 16 and 17 are normal, the throttle valve 2 is moved to the fully closed position S by their operation. There is no obstacle when closing.

Even when the engine is stopped, the throttle valve 2 is held at the open position of the predetermined opening θ ₁ or θ _{2 in} the same manner as when the energization is disabled. There is no accumulation between the outer circumference and the inner circumference of the intake passage 1a. Therefore, the throttle valve 2 can be prevented from sticking due to the accumulation.

  The present invention is not limited to the above-described embodiments, and various design changes can be made without departing from the scope of the gist thereof. For example, another electric motor such as a DC motor can be used instead of the step motor 4. In this case, of course, the spring force of the auxiliary spring 35 is set larger than the friction torque of the motor.

1 is a longitudinal plan view of a throttle valve driving device for an engine according to an embodiment of the present invention. The principal part disassembled perspective view of the same apparatus. 3-3 sectional view of FIG.

Explanation of symbols

2 ... Throttle valve 3 ... Valve shaft 4 ... Step motor 20 as electric motor ... Throttle sensor 21 ... Detection shaft 22 ... Joint 30 ... Stopper plate 33 ..Return spring 34 ... second stopper bolt 35 as stopper means ... auxiliary spring 36 ... engaging means

Claims (3)

In an engine throttle valve drive device in which an electric motor (4) capable of opening and closing the engine is connected to an engine throttle valve (2),
Between the valve shaft (3) of the throttle valve (2) and the stopper plate (30) fitted so as to be rotatable relative thereto, the stopper plate (30) is relatively throttled with respect to the valve shaft (3). 2) provided with engaging means (36) for connecting the valve shaft (3) and the stopper plate (30) when rotating in the closing direction;
The stopper plate (30) is connected to a return spring (33) for urging the stopper plate (2) in the closing direction of the throttle valve (2), and at a predetermined opening (θ ₁ ,. While the stopper means (34) for preventing the return rotation by the return spring (33) of the stopper plate (30) at the position corresponding to θ ₂ ) is placed,
An engine throttle, characterized in that an auxiliary spring (35) for urging the valve shaft (3) in the opening direction of the throttle valve (2) with a spring force weaker than that of the return spring (33) is connected to the valve shaft (3). Valve drive device. In claim 1,
A throttle valve driving device for an engine, characterized in that the predetermined opening of the throttle valve (2) is a low speed opening (θ ₂ ) that enables the vehicle to travel at a very low speed. In claim 1,
The detection shaft (21) of the throttle sensor (20) is connected to the valve shaft (3) via a joint (22), and the spring force of the auxiliary spring (35) is used to remove backlash of the joint (22). A throttle valve drive device for an engine, wherein the detection shaft (21) is urged in the rotational direction.

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