JPS636731B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention mainly relates to an actuator for opening and closing a throttle valve of an internal combustion engine for an automobile.

FIG. 1 is an explanatory diagram of a throttle valve opening/closing mechanism using a conventional actuator as shown in US Pat. No. 4,411,231 and the like.

A throttle valve 2 is provided in the intake passage 1, and a lever 3 is provided in conjunction with the throttle valve 2. The lever 3 is pulled by a tension spring 4 in a direction to close the throttle valve. Further, a wire 5 is attached to the lever 3, and is linked to the accelerator pedal.

In the normal case, the throttle valve 2 is driven in the opening direction by wire transmission by the accelerator pedal, and is driven in the closing direction by the tension spring 4.

The object of the present invention is an actuator for a throttle valve opening/closing mechanism that is provided independently from the above-mentioned throttle valve opening/closing mechanism.

An actuator 6 is fixed at a position where the lever 3 can be rotated, and one end of an output shaft 7 of the actuator 6 comes into contact with the lever 3.

The actuator 6 includes a DC motor 8 as a drive source, and a first gear 10 is attached to one end of a motor shaft 9 so as not to rotate with respect to the motor shaft. A second gear 11 is provided meshing with the first gear 10, and its rotating shaft 12 is held by outer shell members 13 and 14. The third gear 1 meshes with the second gear 11
5 is provided. The third gear 15 is provided with a female threaded portion 16 concentrically with the rotation axis of the gear, and the female threaded portion 16 is adapted to mesh with the male threaded portion 17 of the output shaft 7. It has a structure in which it is held by the outer shell member 14 so as to be non-rotatable but movable in the axial direction.

The operation of the conventional throttle valve opening/closing mechanism constructed as described above will be explained with reference to FIG.

When electricity is applied to the DC motor 8, the DC motor rotates, and rotational force is transmitted from the first gear 10 to the third gear 15 via the second gear 11. Therefore, the valve 2 can be opened and closed.

Normally, the throttle valve is opened and closed as follows.

Opening and closing according to the driver's will is performed by moving the throttle valve 2 via the wire 5 and lever 3 by operating the accelerator pedal. Also,
The electrical input signal supplied to the DC motor 8 is programmed so that the DC motor-type actuator opens and closes in a predetermined pattern depending on the operating state of the machine (idling, decelerating, starting, etc.). The DC motor 8 is controlled to move, and the throttle valve 2 is moved via the output shaft 7 and lever 3.

The conventional actuator for opening and closing the throttle valve described above generally has a safety mechanism as shown in FIG. That is, when the output shaft 7 moves in the direction of opening the throttle valve, a safety mechanism is provided to prevent the engine from running out of control due to excessive opening of the throttle valve.

To explain in detail with reference to FIG. 2, the output shaft 7 moves in the direction in which the throttle valve opens (in the direction in which it protrudes),
When it is in the most protruding state, the male threaded part 1 of the output shaft 7
This is a safety mechanism that prevents the output shaft 7 from protruding more than a predetermined amount due to the screw transmission portion of the female threaded portion 16 of the third gear 15 coming off and the third gear 15 idling.

However, once the output shaft and the third gear are in the position where this safety mechanism operates, the screw transmission is again performed.
When moving the output shaft in the closing direction (retracting direction) of the throttle valve, the DC motor is rotated in the opposite direction, and the third gear 15 is rotated in the opposite direction. However, with only this reverse rotation, only the third gear 15 idles in the reverse rotation direction, and the female threaded portion 16 of the third gear 15
There are cases where the external threaded portion 17 of the output shaft 7 does not mesh with each other, resulting in a serious drawback that control becomes impossible.

Furthermore, if there is an extreme difference in strength or property between the two, such as when the output shaft is made of a metal material and the third gear is made of a plastic material, the male threaded portion 17 of the output shaft 7 may be made of a female threaded portion of the third gear 15. When the threads of the portion 16 are corrected, there is a serious drawback that the threads become misaligned and become locked.

In particular, when the accelerator is suddenly released from the fully open state of the throttle valve when the accelerator is fully depressed, the lever will hit the idling output shaft due to the action of the tension spring. If there is any play between the male and female threads, there is a risk that the meshing part between the male and female threads may come off due to the impact, or the threads may become misaligned and become stuck.

The purpose of the present invention is to
The purpose is to eliminate the above-mentioned drawbacks by preventing play from occurring between the male thread of the output shaft and the female thread of the gear that receives it.

The above object is achieved by providing a means, separate and independent of the lever interlocked with the throttle valve, for generating a force to push the output shaft back in the direction opposite to the direction in which it protrudes when it reaches its maximum protrusion. be done.

According to the present invention configured in this way, even when the lever is disengaged from the output shaft and the output shaft is released from the action of the tension spring for returning the throttle valve, the above-mentioned means can prevent the output shaft from protruding. It can be pushed back in the opposite direction, and even when the output shaft is idling, it is possible to eliminate play between the male thread of the output shaft and the female thread of the gear that receives it, so the lever can be pushed back against the output shaft. Even if you hit it hard, there will be no impact between the two, and there is no risk of the two being broken or jammed.

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 3 is a sectional view showing an embodiment of the actuator of the throttle valve for a fuel supply device according to the present invention. However, similar or identical components to those in FIGS. 1 and 2 are indicated using the same reference numerals.

This embodiment has almost the same configuration as the conventional example. DC motor 8 provided in actuator 6
A gear 10 is attached to one end of a motor shaft 9. A second gear 11 is provided to mesh with the first gear 10, and a third gear 15 is provided to mesh with the second gear 11.

To explain the difference from the conventional one, the output shaft 7
A compression spring 18 is provided between the outer shell member 14 and the inner end face 1 of the outer shell member 14 .
9, and the other end comes into contact with the flange end surface 20 of the output shaft. In FIG. 3, the other end of the compression spring 18 and the flange end surface 20 of the output shaft 7 are separated. This is the direction in which the output shaft 7 closes the throttle valve (retracting direction)
This shows the state when it is on the retracting side. Note that the other structures are the same as those of the conventional example, so explanations will be omitted.

Next, the operation of this embodiment will be explained. First, FIG. 3 shows the state when the output shaft 7 is on the retracting side as described above, and when an electric input is applied to the DC motor 8 from this state, its rotation is caused by the first gear 1.
0 and the second gear 11 to the third gear 15. Since the third gear 15 and the screw-transmitted output shaft 7 are held non-rotatably by the outer shell member 14, when the third gear 15 rotates, the output shaft 7 moves in the axial direction due to the screw transmission. The above movements are the same as in the conventional example.

Now, when an input signal in the direction in which the output shaft 7 protrudes is applied to the DC motor, the output shaft 7 moves in the direction in which it protrudes and reaches a predetermined position. Then, the flange end surface 20 of the output shaft comes into contact with the end surface of the compression spring 18.
At this time, the other end surface of the compression spring 18 is
4, the compression spring 18 moves the output shaft 7 to the third gear 15.
It is possible to generate a force in the direction of pressing against the object.

Further, as the output shaft 7 moves in the protruding direction, the force gradually increases, and reaches its maximum when the screw transmission between the male threaded portion 17 of the output shaft 7 and the female threaded portion 16 of the third gear 15 is disconnected. . Next, when the DC motor 8 is reversely rotated, the third gear 15 is reversely rotated, and the female threaded portion 16 of the third gear 15 is rotated in the reverse direction.
Then, the male threaded portion 17 of the output shaft 7 engages again, and the output shaft 7 moves toward the retraction side.

The force pressing the output shaft against the third gear may be generated when the screw transmission is disengaged by shortening the free length of the compression spring 18.
Also, other spring members may be provided instead of the compression spring.

According to this embodiment, when the screw connection is disengaged and then re-engaged, the compression spring 18 generates a force that presses the output shaft 7 against the third gear 15.
This has the effect of allowing smooth screw transmission. Furthermore, if the above-mentioned pressing force is appropriately selected, even if the difference in material strength and properties between the output shaft 7 and the third gear 15 is extreme, the screw threads will be prevented from slipping and becoming locked. effective.

As explained above, according to the present invention, a force is generated that pushes the output shaft back in the opposite direction to the direction in which it protrudes when it reaches its maximum protrusion, independently of the lever that is linked to the throttle valve. Since the means is provided, even when the output shaft idles, play between the male thread of the output shaft and the female thread of the gear that receives it can be eliminated, and the throttle valve is returned suddenly.
Even if the lever hits the output shaft, there is no impact between the two, and there is no risk of the two being broken or jammed, and the rotational force of the DC motor can be transmitted smoothly to the screw at all times.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing a conventional actuator for opening and closing a throttle valve and an example of its use, Fig. 2 is a partial cross-sectional view showing the main parts of a conventional actuator for opening and closing a throttle valve, and Fig. 3 is an explanatory diagram showing an example of its use. FIG. 2 is a sectional view of an embodiment of an actuator of a throttle valve for a fuel supply device. 6...actuator, 8...DC motor, 9
...Motor shaft, 10...First gear, 11...Second gear, 13, 14...Outer shell member, 15...Third gear, 16...Female thread, 17...Male thread Section 18... Compression spring.

Claims (1)

[Claims of Claims] 1. The drive source is a DC motor, the rotation of the motor is transmitted to a gear, the gear has a female threaded portion concentric with the rotating shaft, and has a male threaded portion that meshes with the female threaded portion. An output shaft is provided, and the output shaft is moved in and out in the axial direction by the rotation of the DC motor to control the contact position with a lever fixed to a throttle valve in the engine intake passage, thereby opening and closing the throttle valve. At the same time, the output shaft moves in the direction of opening the throttle valve, and when it protrudes the most, the threaded connection between the female threaded portion of the gear and the male threaded portion of the output shaft is released.
In the case where the gear is configured to idle, when the output shaft and the lever are separated and the output shaft protrudes at its maximum, the output shaft protrudes independently of the lever. An actuator for a throttle valve for a fuel supply device, characterized in that the actuator is provided with means for generating a pushing force in the opposite direction. 2. In the device described in claim 1, the means for generating a force to push back the output shaft in a direction opposite to the direction in which it projects is provided between the output shaft and an outer shell member that holds the output shaft. An actuator for a throttle valve for a fuel supply device, characterized in that a spring member is provided.