JPH09250366A - Engine throttle valve drive - Google Patents

Abstract

(57) Abstract: When one of the first and second excitation circuits of a stepping motor cannot be energized, the throttle valve can always be given a predetermined opening by normal operation of the other energizing circuit, and the engine is stopped. And also enables the engine to start and the vehicle to run at a very low speed in cold weather. SOLUTION: A stopper plate 30 biased in a closing direction of the throttle valve 2 by a return spring 33 is rotatably fitted to a valve shaft 3 of a throttle valve 2 driven by a step motor 4. When the stopper plate 30 is rotated back by the force of the return spring 33, the valve shaft 3 is rotated in the closing direction of the throttle valve 4 through the engagement means 36, but the throttle valve 2 is opened at a predetermined opening θ, for example, a fast idle opening. When it reaches the position, the stopper bolt 34 blocks the return rotation of the stopper plate 30. The valve shaft 3 is connected to an auxiliary spring 35 that biases the valve shaft 3 in the opening direction with a spring force weaker than that of the return spring 33.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a throttle valve of an engine, which is connected with a step motor for opening and closing the throttle valve. The step motor has a plurality of energized phases for stepping the step motor. The present invention relates to an engine throttle valve drive device provided with first and second excitation circuits.

[0002]

2. Description of the Related Art Such a throttle valve driving device is already known, as disclosed in, for example, Japanese Patent Laid-Open No. 6-213012.

By the way, in the throttle valve drive device disclosed in the above publication, the first and second step motors are used.
Even when one of the excitation circuits fails, the normal excitation circuit is energized to open the throttle valve with a small opening to prevent engine stalling.

[0004]

However, in the one disclosed in the above publication, there is a difference in the opening degree of the throttle valve between the case where only the first excitation circuit is energized and the case where only the second excitation circuit is energized. .

The present invention has been made in view of such circumstances, and the throttle valve is always operated by operating the normal one-sided excitation circuit even when the first and second excitation circuits cannot be energized. It is an object of the present invention to provide the throttle valve drive device that can be opened to a constant predetermined opening.

[0006]

In order to achieve the above object, the present invention provides, in the above-mentioned throttle valve drive device, between a valve shaft of a throttle valve and a stopper plate which is rotatably fitted thereto. When the stopper plate rotates in the closing direction of the throttle valve relative to the valve shaft, engaging means for connecting the valve shaft and the stopper plate is provided, and the stopper plate is biased in the closing direction of the throttle valve. And a stopper means for blocking the return rotation of the stopper plate by the return spring at the position corresponding to the predetermined opening of the throttle valve, while the return spring is weaker than the return spring on the valve shaft. When an auxiliary spring that urges the throttle valve in the opening direction by force is connected and one of the first and second excitation circuits of the step motor becomes unenergizable, the other excitation circuit operates normally. That it has to open the throttle valve to the predetermined opening in cooperation with the auxiliary spring to the first feature.

In addition to the above features, the present invention connects the detection shaft of the throttle sensor to the valve shaft via a joint, and rotates the detection shaft by the spring force of the auxiliary spring to eliminate the backlash of the joint. The second feature is that the bias is applied in the direction.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below based on 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 pair of left and right valve shafts 3 of a butterfly type throttle valve 2 for opening and closing an intake passage 1a. It is rotatably supported via ball bearings 7, 7.

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

The lost motion mechanism 6 includes an output shaft 5
And a drive plate 8 and a driven plate 9 fixed to the opposite ends of the valve shaft 3, respectively. These drive and driven plates 8 and 9 are
Engaging pieces 10, 1 facing each other along their circumferential direction
1 is formed, and these engaging pieces 10 and 11 are arranged so as to abut each other when the drive plate 8 rotates in the opening direction of the throttle valve 2 relative to the driven plate 9.
Further, the driving and driven plates 8 and 9 are provided with engaging pieces 10 and
A connecting spring 12 for urging the contacting direction of 11 is connected.
Further, a stopper piece 13 is formed on the driven plate 9, and a stopper bolt 14 for abutting against the stopper piece 13 and defining the fully closed position 0 (see FIG. 3) of the throttle valve 2 is screwed on the throttle body 1. Be worn.

Therefore, when the step motor 4 is operated in the opening direction (normal rotation direction) of the throttle valve 2, the drive plate 8 driven by the output shaft 5 brings the engaging pieces 10 and 11 into contact with each other and is driven. It is possible to drive the plate 9 in the forward direction and open the throttle valve 2 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 drives 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 0, the stopper piece 13 of the driven plate 9 moves to the first stopper bolt 1
4, the reverse rotation of the step motor 4 thereafter causes the engagement springs 10 and 11 to be separated from each other while the connection spring 1 is separated.
2 will be deformed, so that the throttle valve 2
It is possible to prevent an excessive closing torque from being applied to.

The step motor 4 has a unipolar type excitation circuit as shown in FIG. 4 or a bipolar type excitation circuit as shown in FIG. Each of these circuits is provided with first and second exciting circuits 16 and 17, and the first exciting circuit 16 is provided with transistors 18a and 18c for respectively establishing energization of the first and third phases a and c. In addition, the second excitation circuit 17 is provided with transistors 18b and 18d for establishing conduction of the second and fourth phases b and d, respectively.

Thus, the energization of the first to fourth phases a to d is
Simultaneous energization of a and b → Single energization of b → Simultaneous energization of b and c →
Single energization of c → Simultaneous energization of c and d → Single energization of d → d,
Simultaneous energization of a → single energization of a → (repeated below) By the control as described above, the step motor 4 is rotated stepwise at a constant angle (0.9 ° in the illustrated example). Such energization control is performed by the electronic control unit 15 (see FIG. 1).

Referring again to FIGS. 1 and 2, 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 jointed 22. Are connected via. 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 that is sandwiched in the circumferential direction of the detection shaft 21 is formed.

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

At the right end of the valve shaft 3, the joint plate 2 is attached.
The boss 30 a of the stopper plate 30 is rotatably fitted adjacent to the position 3. These joint plate 23 and stopper plate 3
The engaging pieces 31, 32 facing each other along their circumferential direction are formed on the 0.
Are arranged so as to contact each other when the joint plate 23 rotates in the opening direction of the throttle valve 2 relative to the stopper plate 30. These engagement pieces 31 and 32 constitute an engagement means 36 that connects the stopper plate 30 and the valve shaft 3 in a fixed rotation direction.

A return spring 23 is connected to the stopper plate 30 to bias the stopper plate 30 in the closing direction of the throttle valve 2. Thus, the elastic force of the return spring 23 acts on the valve shaft 3 from the stopper plate 30 via the joint plate 23 so as to close the throttle valve 2.

A second stopper bolt 34 (stopper means), which abuts on the engaging piece 32 of the stopper plate 30 and defines the limit of the return rotation of the stopper plate 30 by the return spring 33, is arranged opposite to the engaging piece 32. The bolt 34 is screwed onto 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 provided with a predetermined opening, that is, a fast idle opening of 2.3 ° in the illustrated example.

Further, the detection shaft 21 is provided with an auxiliary spring 35 for urging the detection shaft 21 in the opening direction of the throttle valve 2. The spring force of the auxiliary spring 35 is set to be much weaker than that of the return spring 33. Moreover, the spring force eliminates the backlash of the joint 22, and
The two engaging pieces 31 and 32 act so as to always contact each other.

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

Next, the operation of this embodiment will be described.

First, when the step motor 4 is operated, as shown in FIG. 6 (I), first, the first and second phases a and b are simultaneously energized. Then, the throttle valve 2
By energizing a and b, the step motor 4 moves the throttle valve 2
Is held at the fully open position 0 and the valve opening force of the auxiliary spring 35 is balanced, that is, at the idle opening B slightly opened from the fully closed position 0.

Next, when the accelerator pedal is depressed to accelerate the rotation of the engine, the electronic control unit 15 causes the above-mentioned first to fourth phases based on the output signal of the accelerator sensor 38 corresponding to the depression amount. The step motor 4 is operated by the energization control of a to d, and the throttle valve 2 is opened. Then, the opening of the throttle valve 2 is detected by the throttle sensor 20, the change of the engine speed is detected by the engine rotation sensor 39, and 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 the input signals so that the engine speed and the boost pressure match the depression amount of the accelerator pedal.

Now, due to some failure, the first excitation circuit 1
Assuming that 6 cannot be energized, the electronic control unit 15
Performs the following work according to the flowchart of FIG.

First, the process proceeds from step S1 to step S2 and then to step S3 to energize the second phase b for a predetermined time. As a result, as shown in (II) of FIG. 6, the step motor 4 tries to hold the throttle valve 2 at the position of the minimum opening 0.9 ° corresponding to the second phase b. However, when the throttle valve 2 is in the opening range of 0 ° to 2.3 °, the throttle valve 2 receives the opening force of the auxiliary spring 35. At the position offset to the opening side, the holding force by the energization of the second phase b and the valve opening force by the auxiliary spring 35 are balanced. That is, the opening position of the throttle valve 2 comes closer to the opening position of the two fourth phases d, d arranged on both sides of the opening position.

Therefore, when the operation proceeds to step S4 and the energization state of the fourth phase d is switched, the step motor 4 moves toward the position of the opening 4.5 ° corresponding to the fourth phase d located on the opening side toward the throttle valve. Drive 2 The amount of electricity supplied to the fourth phase d at this time is set so that the driving torque of the step motor 4 generated thereby does not exceed the valve closing torque due to the set load of the return spring 33.

Therefore, when the throttle valve 2 is driven to the open position of 2.3 °, the set load of the return spring 33 prevents further opening of the throttle valve 2 due to the abutment of the engaging pieces 31, 32. Therefore, the throttle valve 2 is 2.3 °
Held in the open position. Since this opening is the fast idle opening in the illustrated example, the engine can be started and the vehicle can be driven at a very low speed in cold weather as well as engine stall prevention.

If the second excitation circuit 17 cannot be energized, the process proceeds from step S1 to step S5 to step S6 to energize the third phase c. The energization amount at this time is also set so that the driving torque of the step motor 4 generated thereby does not exceed the valve closing torque due to the set load of the return spring 33. Therefore, as shown in (III) of FIG. 6, the step motor 4 moves toward the position of the minimum opening of 2.7 ° corresponding to the third phase c and the throttle valve 2
When it reaches the open position of 2.3 °, the set load of the return spring 33 prevents the throttle valve 2 from further opening due to the abutment of the engaging pieces 31 and 32 as before. As a result, also in this case, the throttle valve 2 is held at the fast idle opening degree of 2.3 ° similarly to the time when the first excitation circuit 16 cannot be energized, the engine stall is prevented, the engine is started in cold weather, and the vehicle runs at a low speed. To enable.

The present invention is not limited to the above embodiment, and various design changes can be made without departing from the scope of the invention. For example, by the initial energization of only the second phase b,
It is also possible to give the throttle valve 2 an idle degree B. Further, the predetermined opening θ can be set to an opening other than the fast idle opening. In the above embodiment, when one of the excitation circuits cannot be energized, the amount of electricity supplied to the fourth phase d or the third phase c is balanced with the valve closing torque of the stepping motor 4 due to the set load of the return spring 33. It is possible to give the throttle valve 2 a constant opening larger than 2.3 °, for example, 2.5 ° by setting the above. Further, the step motor 4 may be of a multi-phase type other than the 4-phase type.

[0031]

As described above, according to the first feature of the present invention, even when either of the first and second exciting circuits becomes unable to be energized, one or both phases of the normal exciting circuit are By appropriately energizing the phases, the throttle valve can always be opened to a constant predetermined opening in cooperation with the auxiliary spring, and the engine can be started in cold weather and the vehicle can run at a very low speed.

According to the second aspect of the present invention, the auxiliary spring also serves as a spring for eliminating backlash of the joint connecting the throttle valve and the throttle sensor, which improves the detection accuracy of the throttle sensor. The structure can be simplified.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional plan view of a throttle valve drive device of the present invention.

FIG. 2 is an exploded perspective view of main parts of the device.

FIG. 3 is a sectional view taken along line 3-3 in FIG. 1;

FIG. 4 is an excitation circuit diagram of an example of a step motor.

FIG. 5 is an excitation circuit diagram of another example of the step motor.

FIG. 6 is an explanatory view of the operation of the device of the present invention.

FIG. 7 is a flowchart for opening the throttle valve by a predetermined opening when one of the first and second excitation circuits cannot be energized.

[Explanation of symbols]

 a 1st phase b 2nd phase c 3rd phase d 4th phase 2 Throttle valve 3 Valve shaft 4 Step motor 15 Electronic control unit 16 1st excitation circuit 17 2nd excitation circuit 20 Throttle sensor 21 Detection shaft 22 Joint 30 Stopper plate 33 Return Spring 34 Second Stopper Bolt as Stopper Means 35 Auxiliary Spring 36 Engaging Means

Claims (2)

[Claims] 1. A throttle valve (2) of an engine is connected to a step motor (4) for opening and closing the throttle valve (2), and the step motor (4) is provided with a plurality of energized phases (steps) for operating the step motor. a and b) first and second components
In an engine throttle valve driving device provided with an excitation circuit (16, 17), between a valve shaft (3) of a throttle valve (2) and a stopper plate (30) which is rotatably fitted thereto. Engaging means (36) for connecting between the valve shaft (3) and the stopper plate (30) when the stopper plate (30) rotates relative to the valve shaft (3) in the closing direction of the throttle valve (2). A return spring (33) for urging the stopper plate (30) in the closing direction of the throttle valve (2) is connected to the stopper plate (30) and corresponds to a predetermined opening (θ) of the throttle valve (2). While the stopper means (34) for preventing the return rotation of the stopper plate (30) by the return spring (33) is placed at the position, the stopper means (34) is applied to the valve shaft (3) with a weaker spring force than the return spring (33). Auxiliary for urging the throttle valve (2) in the opening direction The first and second excitation circuit (16 I (35) connecting the stepping motor (4),
When either one of 17) becomes unable to be energized, the throttle valve (2) is opened to the predetermined opening (θ) by the normal operation of the other excitation circuit and the cooperation of the auxiliary spring (35). An engine throttle valve drive device characterized by the above. 2. The valve shaft (3) according to claim 1, wherein a detection shaft (2) of a throttle sensor (20) is provided.
1) is connected through a joint (22), and the detection shaft (21) is urged in the rotational direction by the spring force of an auxiliary spring (35) in order to remove the backlash of the joint (22). The engine throttle valve drive.