JPH0152636B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an air supply device for an automobile engine, and more particularly to an actuator for opening and closing a throttle valve.

FIG. 1 is a sectional view of a conventional throttle valve opening/closing mechanism. A throttle valve 2 is installed inside the intake passage 1, and a shaft to which the throttle valve 2 is attached fixes a lever 3 outside the intake passage 1. The lever 3 is formed of a semicircular part around which a wire 5 is wound and an L-shaped part, and one end of the semicircular part is locked to the upper end of a cylinder forming the intake passage 1 by a tension spring 4. Therefore, the throttle valve 2 is given a rotational force in the closing direction by the tension spring 4, and the end of the lever 3 is brought into contact with the output shaft 7 of the actuator 6.

Actuator 6 is motor shaft 9 of DC motor 8
The first gear 10 attached to the first gear 10, the second gear 11 meshing with the first gear 10, and the second gear 11
The third gear 15 meshing with the third gear 1
A male thread 17 that screws into the female threaded portion 16 of the center hole of No. 5
These gears and the output shaft 7 are housed in outer shell members 13 and 14 and are integrally constructed. Note that the rotating shaft 12 is the second
A gear 11 is fixed and rotatably supported by outer shell members 13 and 14, and a hexagonal portion is provided at the left end of the output shaft 7 and is loosely engaged with a hexagonal hole of outer shell member 13. That is, when the DC motor 8 rotates in the forward and reverse directions, it is decelerated by the gear mechanism, and the output shaft 7 is slowly moved left and right.

FIG. 2 is an enlarged sectional view showing the third gear and output shaft of FIG. 1. A spring washer 18 and a washer 19 are interposed between the end surface 15a of the third gear 15 on the lever 3 side and the intermediate end surface 7a of the output shaft 7,
The leftward movement range of the output shaft 7 is restricted.

The operation of the conventional throttle valve opening/closing mechanism configured as described above will be described next. When a current flows through the DC motor 8, it decelerates and rotates the third gear 15 via the first gear 10 and the second gear 11.
5 linearly moves the output shaft 7 in the axial direction by screw transmission. Since the right end of this output shaft 7 is in contact with the tip of the lever 3 which is rotated by the tension spring 4, the throttle valve 2 is opened and closed by changing the current flowing to the DC motor 8 and its polarity. be able to.

The throttle valve 2 is normally opened and closed as follows. One is opening and closing according to the driver's will, and when the driver depresses the accelerator pedal, the wire 5 is pulled and the opening degree of the throttle valve 2 is rapidly increased. Further, when the driver weakens the depression force, the opening degree of the throttle valve 2 decreases due to the spring force of the tension spring 4. The other one is opening/closing by the actuator 6. In this case, the operating state of the engine is detected and a predetermined control operation is performed. For example, the opening degree of the throttle valve 2 is automatically adjusted by program-controlling the energization time and polarity of the DC motor 8 during idling, deceleration, or startup. That is, it is used as part of an electronically controlled driving system.

Now, the lever 3 side end surface 15a of the third gear 15
is pressed against the intermediate end surface 7a of the output shaft 7 in contact with the spring washer 18 and the washer 19. The tightening force is determined by the rotational power of the DC motor 8, but once it is tightened, even if the direction of rotation of the DC motor 8 is reversed to release the tightening, the third gear 1
An accident occurred in which the motor 5 did not rotate and the DC motor 8 also stopped moving. This is caused by the lever-side end surface 15a of the third gear 15 biting into the spring washer 18. This makes it impossible to smoothly control the opening of the throttle valve 2, and an improvement has been desired. .

Note that, for example, US Pat. No. 4,212,272 discloses related technology.

An object of the present invention is to provide a throttle valve opening/closing actuator that can smoothly control the throttle valve opening through relatively simple improvements. A DC motor that is driven by the signal obtained by the DC motor, a gear mechanism that transmits the rotational force of this DC motor, and a male screw that is screwed into the internal thread formed in the center hole of the final stage gear of this gear mechanism. In the throttle valve opening/closing actuator, the output shaft has an output shaft provided with a part, and the output shaft pushes a lever attached to the throttle valve shaft to control the opening of the throttle valve. However, at a position where the output shaft moves to the limit in the direction of closing the throttle valve and stops, a member for preventing movement of the output shaft is provided, which forms a plane-to-spherical contact.

FIG. 3 is a sectional view of a throttle valve opening/closing actuator according to an embodiment of the present invention, in which the same parts as in FIG. 1 are given the same reference numerals. In this case, the left end surface 7b of the output shaft 7 when the throttle valve 2 reaches its minimum opening comes into contact with a ball 20 made of hard synthetic resin, and the movement of this ball 20 is restricted by the outer shell member 13. Therefore, there is no need for a buffer member such as a conventional spring washer 18 between the lever-side end surface 15a of the third gear 15 and the intermediate end surface 7a of the output shaft 7.

The ball 20 is made of a hard synthetic resin material, such as acetal resin, and when the output shaft 7 moves to the leftmost limit, the center of the left end surface 7b contacts a small portion of the ball 20 and stops. However, the ball 20 and the center of the end surface 7b do not bite into each other. Therefore, when the output shaft 7 moves to the right, the ball 20 and the output shaft 7 are easily separated, and the movement of the output shaft 7 is not hindered.
Further, even if the ball 20 rolls within the outer shell member 13, it does not generate noise, and since it has some elasticity, the output shaft 7 is reliably and quickly started in the right direction. This gives rise to the advantage of

Note that similar advantages can be obtained by using a steel ball instead of a synthetic resin ball 20, but in this case, when the steel ball contacts the left end surface 7b of the output shaft 7 and the outer shell member 13, there is a slight noise. occurs.

Generally, the force required to loosen a tightened condition is expressed as the product of the tightening force, the distance from the center of the axis of the point on which the tightening force acts, and the coefficient of friction.
By using the ball 20, which is a rolling thrust bearing, as described above, it has become possible to significantly reduce the force required to loosen a tightened state. This greatly improves the ability to start the output shaft 7 in the reverse direction.

The throttle valve opening/closing actuator of this example has a hard ball interposed between the left end of the output shaft and the outer shell member, which greatly improves the ability to start the output shaft in the opposite direction, making it easier to operate. The effect of creating a structure is obtained.

FIG. 4 is a sectional view of an actuator according to another embodiment of the present invention, in which the first gear 10
A ball 20 is interposed between the shaft end 10a of the output shaft 7 and the left end surface 7b of the output shaft 7, thereby making the actuator 6 compact and achieving the same effect as the actuator shown in FIG. Note that the second gear 11 meshes with the lower side of the first gear 10, and the third gear 15 meshes with the right side of the second gear 11, so that the size is significantly reduced.

FIG. 5 is a cross-sectional view of an actuator that is a modification of FIG.
A ball 20 is interposed between the ball 20 and b.

FIG. 6 is a sectional view of an actuator that is another modification of FIG. 4. In this case, the third gear 15
A small protrusion 15b is provided at the bottom of the center hole in which the female threaded portion 16 is formed along the central axis of the output shaft 7, and a ball 20 is interposed between the small protrusion 15b and the left end surface 7b of the output shaft 7.

In addition, since the actuator 6 shown in FIGS. 4 to 6 has a coiled compression spring 22 interposed between the third gear 15 and the outer shell member 13, the third gear 15 is always on the right side. However, when the driver depresses the pedal, the output shaft 7 is released. Therefore, the spring force of the compression spring 22 causes the third gear 15 to
is separated from the micro switch 23, so the DC motor 8 stops rotating. That is, the microswitch 23 cuts off the DC supplied to the DC motor 8.

In the actuator of this embodiment shown in FIGS. 4 to 6, the output shaft and the protrusion come into contact with each other through the hard ball, so the restartability of the output shaft is improved, and the output shaft is connected to the third gear. Since it is housed in the interior, an advantage can be obtained that the structure can be made even more compact.

FIG. 7 is a sectional view of essential parts of an actuator according to another embodiment of the present invention, in which the same parts as in FIG. 2 are given the same reference numerals. In this case, the ball 20 is fixed to the left end of the outer shell member 13 housing the output shaft 7, and is opposed to the left end surface 7b of the output shaft 7. Since the ball 20 is fixed in this manner, it will not come into contact with surrounding members and generate sound.

FIG. 8 shows a modification of FIG. 7, in which a ball 20 is partially embedded and fixed in the hexagonal part at the left end of the output shaft 7. Further, FIG. 9 is a front view of the output shaft 7 without a hexagonal portion, and in this case, a small ball 20 is fixed to the left end of the output shaft 7. Note that there is no difference in function even if these balls 20 are fixed or rotatably attached.

In the embodiments shown in FIGS. 7 to 9, by fixing the ball to the inside of the outer shell member or to the left end of the output shaft, the contact area of the ball is kept constant and reproducibility is improved. This has the effect of preventing the generation of noise when rolling.

FIG. 10 is a sectional view of an actuator according to still another embodiment of the present invention, in which the same parts as in FIG. 3 are given the same reference numerals. In this case, when the output shaft 7 moves the most in the direction of closing the throttle valve 2, the left end surface 7b of the output shaft 7
It is designed to stop when it comes into contact with. At this time the third
The lever-side end surface 15a of the gear 15 is free without contacting other members, and spring washers and the like have been removed. Further, the position where the left end surface 7b of the output shaft 7 contacts the protrusion 21 is made to be as close to the center of the output shaft 7 as possible, and at least the male threaded portion 17
within the effective radius of

In the actuator configured in this manner, when the output shaft 7 moves to the left, it comes into contact with the protrusion 21 and stops, and is tightened by the rotational power of the DC motor 8.
The force required to loosen something that has been tightened is
As described above, the output shaft 7 easily separates from the protrusion 21 when the DC motor 8 rotates in the opposite direction, since it is expressed as the product of the clamping force, the distance from the shaft center of the point on which the clamping force is applied, and the coefficient of friction. In other words, the starting performance during reverse rotation has been significantly improved.

In the actuator of this embodiment, by arranging the protrusion of the outer shell member and the center of the left end face of the output shaft to face each other without the interposition of a ball, the starting performance during reverse rotation of the DC motor is greatly improved. Since there is no intervening ball, the effect of being smaller and cheaper can be obtained.

Next, as in FIG. 10, various types of actuators that do not use balls will be considered.

FIG. 11 shows the actuator shown in FIG. 4 with the ball removed. In this case, a protrusion 21 is provided at the tip of the shaft of the first gear 10, and the output shaft 7
stops when the left end surface 7b contacts the protrusion 21.

FIG. 12 shows a case where the ball is removed from the actuator of FIG. 5. At this time, the left end surface 7b of the output shaft 7 comes into contact with the protrusion 21 formed at the tip of the motor shaft 9, and the output shaft 7 stops.

FIG. 13 shows a case where the ball is removed from the actuator shown in FIG. 6, and a small protrusion 15b is provided at the bottom of the center hole in which the female thread 16 is formed along the central axis of the third gear 15. The small protrusion 15b and the left end surface 7b of the output shaft are directly opposed to each other.

The actuator shown in Figs. 11 to 13 described above has a structure in which the left end surface of the output shaft and the protrusion formed on the center line of the output shaft come into contact with each other without intervening a ball, thereby forming a stopper for the output shaft. Therefore, the effect of improving the starting performance when the throttle valve is opened can be obtained.

Although various examples of the stopper mechanism for the output shaft 7 have been described above, such an actuator 6 is provided with a switch mechanism. That is, when the driver operates the accelerator, the lever-side end surface 7c of the output shaft 7 is away from the lever 3, and at this time, the compression spring 22 causes the third gear 15 and the output shaft 7 to move toward the lever. pushed to the side. This situation is shown in Figure 4~
This is common to the output shaft 7 screwed into the center hole of the third gear 15 shown in FIGS. 6 and 11 to 13, and the micro switch 23 is turned off at this time. It is connected so that That is, when the driver is depressing the pedal, no current flows to the DC motor 8, and the actuator 6 is in a rest state.

When the driver is not operating the accelerator, the lever 3 contacts the lever-side end surface 7c of the output shaft 7 and pushes the output shaft 7 to the left. At this time, the third gear 15 and the output shaft 7 compress the compression spring 22 and push it toward the DC motor 8, turning the switch 23 on.
As a result, the DC motor 8 starts and moves the output shaft 7 via the gear mechanism. That is, throttle valve 2
To increase the opening degree, move the output shaft 7 to the right,
During idling operation when the opening degree of the throttle valve 2 is at its minimum, the output shaft 7 moves to the left and the ball 20 or the protrusion 2
It will be in contact with the 1st class. Incidentally, when transitioning from this state to a state in which the opening degree of the throttle valve 2 is larger, starting of the output shaft 7 is facilitated by using the above-mentioned protrusion.

The throttle valve opening/closing actuator of the present invention has the effect of improving restartability of the output shaft and smoothly controlling the throttle valve opening through relatively simple modification.

[Brief explanation of drawings]

Figure 1 is a sectional view of a conventional throttle valve opening/closing mechanism;
The figure is an enlarged sectional view of the main part of FIG. 1, FIG. 3 is a sectional view of an actuator for opening and closing a throttle valve, which is an embodiment of the present invention, and FIG. 4 is a sectional view of an actuator, which is another embodiment of the present invention. 5 and 6 are sectional views of an actuator that is a modification of the one shown in FIG. 10 is a cross-sectional view of an actuator which is a modification of FIG. 7, FIG. 10 is a sectional view of an actuator which is still another embodiment of the present invention, and FIG. 11 is a sectional view of an actuator which is a modification of FIG. 12 is a sectional view of an actuator that is a modification of FIG. 5, and FIG. 13 is a sectional view of an actuator that is a modification of FIG. 6. 1... Intake passage, 2... Throttle valve, 3... Lever, 4...
Pull spring, 5... Wire, 6... Actuator, 7
...Output shaft, 8...DC motor, 9...Motor shaft, 10
...first gear, 11...second gear, 12...rotating shaft, 13, 14...outer shell member, 15...third gear,
16...Female thread part, 17...Male thread part, 20...Ball, 21...Protrusion part, 22...Compression spring, 23...Micro switch.

Claims (1)

[Claims] 1. A DC motor driven by a signal obtained by detecting the operating state of the engine, a gear mechanism that transmits the rotational force of this DC motor, and a final stage gear of this gear mechanism. An actuator for opening and closing a throttle valve, which has an output shaft provided with a male threaded part formed in the center hole of the center hole and has a male threaded part screwed into the female threaded part, and this output shaft pushes a lever attached to the throttle valve shaft to control the opening degree of the throttle valve. , a member for preventing movement of the output shaft forming a plane-to-spherical contact at a position where the end surface of the output shaft opposite to the lever moves to an extreme limit in the direction of closing the throttle valve and stops; An actuator for opening and closing a throttle valve, characterized in that it is provided with. 2. A patent in which the member for preventing interference with movement of the output shaft is a ball made of hard synthetic resin interposed between an outer shell member housing the output shaft and an end surface of the output shaft on the opposite side from the lever. An actuator for opening and closing a throttle valve according to claim 1. 3. A patent in which the movement obstruction prevention member of the output shaft is a ball made of hard synthetic resin accommodated in the center hole formed at the end surface of the output shaft opposite to the lever and the center of the final stage gear. An actuator for opening and closing a throttle valve according to claim 1. 4. Claim 1, wherein the member for preventing movement of the output shaft is a protrusion formed on the inner surface of the outer shell member housing the output shaft on the opposite side from the lever.
Actuator for opening and closing the throttle valve as described in . 5. The throttle valve opening/closing actuator according to claim 1, wherein the member for preventing movement of the output shaft is a protrusion formed at the bottom of the center hole of the final stage gear.