JP2003083092A - Intake restriction device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an intake restriction device for an internal combustion engine capable of reducing drive load of a drive motor in a normal temperature region while preventing improper full closing return when a temperature is extremely low. SOLUTION: In this intake restriction device for the internal combustion engine provided with an intake throttle valve 10 for opening and closing an intake passage 10a, the drive motor 50 for driving a valve shaft 12 of the intake throttle valve 10, an energizing means 30 for energizing the valve shaft 12 in the direction of closing the valve, and a control means 60 for controlling the drive motor 50, the energizing means 30 is provided with a temperature sensitive member 39 for increasing an energizing force energizing the valve shaft 12 in accordance with the reduction of temperature at one ends of return springs 31, 32 engaged with the valve shaft 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intake throttle device for an internal combustion engine.

[0002]

2. Description of the Related Art An intake throttle device is known which includes an intake throttle valve that opens and closes an intake passage of an internal combustion engine, a drive motor that drives the intake throttle valve, and control means that controls the drive motor.

In this type of intake throttle device, the drive motor can drive the intake throttle valve without increasing the size of the drive motor. This drive motor is provided with a valve of the intake throttle valve via a reduction gear having an intermediate gear. Driving the axis.

When the drive motor is not energized, an urging means such as a return spring for urging the valve shaft in the fully closing direction is provided so that the intake throttle valve returns to the opening degree corresponding to the fully closed state.

[0005]

SUMMARY OF THE INVENTION In the above-mentioned conventional configuration,
Since a return spring or other urging means for urging the valve shaft in the fully closed direction is provided, if the drive motor or the control system for controlling the drive motor fails, the intake air as a normally closed valve that maintains the internal combustion engine in a safe state Although a throttling device can be provided, it is necessary to increase the urging force of the urging means in order to provide it as a normally closed valve even in an extremely low temperature state of -40 ° C. However, if an attempt is made to increase the urging force of the urging means, there is a problem that the size of the drive motor as a drive source for driving the valve shaft becomes large.

The present invention has been made in consideration of such circumstances, and therefore an object of the present invention is to prevent a fully closed return defect at an extremely low temperature and to prevent a drive load of a drive motor in a normal temperature range from being increased. An object of the present invention is to provide an intake throttle device for an internal combustion engine that can be reduced.

[0007]

According to claim 1 of the present invention, an intake throttle valve for opening and closing an intake passage, a drive motor for driving a valve shaft of the intake throttle valve, and a valve shaft for closing the valve shaft. In an intake throttle device for an internal combustion engine, comprising:
The urging means includes a temperature sensitive member at one end of a return spring that engages with the valve shaft and that changes the urging force that urges the valve shaft according to temperature changes.

The urging means for urging the valve shaft in the valve closing direction includes:
Since a temperature sensitive member that changes the urging force that urges the valve shaft according to the temperature change is provided at one end of the return spring that engages with the valve shaft, for example, the valve shaft in a low temperature range, especially in a very low temperature, It is possible to secure the biasing force that returns to the closing direction.

Therefore, it is possible to prevent the full-close return from occurring when the temperature is extremely low as described above, and the drive motor in the normal temperature range has the urging force of the urging means for urging the valve shaft according to the temperature rise. It is possible to reduce the driving load applied via the valve shaft due to the temperature sensitive member that lowers the temperature.

According to claim 2 of the present invention, the urging means comprises:
When the drive motor is not energized, the valve shaft is rotated to a default valve shaft position in the vicinity of fully closed, which is an intermediate position between the fully opened valve shaft position and the fully closed valve shaft position.

When the drive motor is de-energized, the urging means having a temperature sensitive member for increasing the urging force for urging the valve shaft in response to the temperature drop has a fully open valve shaft position regardless of the ambient temperature. It is possible to return to the default valve shaft position in the vicinity of the fully closed position, that is, the opening corresponding to the fully closed position, which is intermediate between the fully closed valve shaft position.

Rotating the valve shaft to the default valve shaft position near the fully closed position means that the spring of the urging means includes the first spring and the first spring, as described in claim 3 of the present invention. Two springs and an intermediate lever that is sandwiched between the first spring and the second spring and is rotatable around the valve shaft are provided. One end of the first spring is one on the valve shaft and the other is on the other. One end of the second spring is engaged with the intermediate lever and the other end of the second spring is engaged with the temperature sensitive member. When the drive motor is not energized,
When returning from the fully open to the fully closed valve shaft position, the intermediate lever contacts the default locking member, so that the valve shaft is locked at the valve shaft position near the fully closed position.

A first spring and a second spring as biasing means.
The intermediate levers, which are sandwiched between the first spring engaging the valve shaft and the second spring engaging the temperature sensitive member, are sandwiched between the springs of the valve, and abut on the default locking member, whereby Since the shaft is locked at the valve shaft position near the fully closed position, it is possible to reliably return the opening degree to the fully closed position.

According to a fourth aspect of the present invention, the default locking member has a screwing portion capable of screwing,
The default valve shaft position can be changed according to the amount of external screwing.

That is, it is possible to change the screwing amount of the default locking member according to the required intake flow rate for each internal combustion engine equipped with the intake throttle device.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the intake throttle device for an internal combustion engine according to the present invention will be described below with reference to the drawings.

FIG. 1 is a partial sectional view showing the structure of an intake throttle device according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of the intake throttle device of FIG. 1 seen from the direction II in the cover.
FIG. 3 is a schematic diagram showing a relationship relating to the operation of the valve shaft of the intake throttle device of the present embodiment, the biasing means, particularly the intermediate lever, and the first and second springs.
Is a substantially fully closed state, FIG. 3 (b) is a valve open state at a substantially default valve shaft position, and FIG. 3 (c) is a valve shaft opening larger than the default valve shaft position and smaller than a fully closed state. It is a schematic diagram showing the state of a valve shaft opening degree. FIG. 4 is a graph showing the torque characteristic of the biasing means according to the valve shaft opening of the intake throttle device of this embodiment in FIG. 3, and point a is the valve shaft opening related to FIG. The torque value and point b in degrees are shown in FIG.
The torque value in the valve shaft opening state related to (c) and the point c are graphs showing the torque value at the valve shaft opening state related to FIG. 3 (c).

As shown in FIG. 1, the intake throttle device 1 includes an intake throttle valve 10, a speed reducer 20, an urging means 30, a valve shaft opening sensor 40, a drive motor 50, and a control means 60.
It is configured to include and.

The intake throttle valve 10 includes a valve housing 11 and
A valve shaft 12 rotatably supported in the valve housing 11,
The valve body 13 is fixed to the valve shaft 12 and opens and closes the intake passage 11a formed in the valve housing 11 to change the opening area of the intake passage 11a.

As shown in FIG. 1, the valve housing 11 has a substantially cylindrical shape in the direction perpendicular to the plane of the drawing, and has an intake passage 11a formed therein. The left and right walls 11b1 and 11b2 of the valve housing 11 rotatably support the valve shaft 12.

One wall 11b1 supporting the valve shaft 12
Is provided with a bearing member 19a, and the valve shaft 12 is
The valve housing 11 is rotatably supported by the bearing member 19a and a bearing member 19b described later.

A substantially fan-shaped input gear 21 of the speed reducer 20 is engaged with the other wall 11b2. The input gear 21 is preferably substantially fan-shaped corresponding to the range of the valve shaft opening degree of the valve shaft 12 in which the valve body 13 of the intake throttle valve 10 can move from the fully closed state to the fully opened state. As a result, the weight of the input gear, that is, the speed reducer 20 described later can be reduced.

The bearing member 19b provided on the other wall 11b2 shown in FIG. 1 transmits a force from the outside to the valve shaft 12 supported by the bearing member 19b, that is, the reduction gear 20.
A ball bearing is desirable because the driving force of the drive motor 50 acts via the.

The other wall 11b2 is provided with an urging means 30 for urging the valve shaft 12 in the rotational direction.

This biasing means 30 is provided at least for the valve shaft 12
Has a biasing spring 32 for biasing the valve in the valve closing direction. As a result, when the drive motor 50 or the control means 60 is not in a normal state, that is, when the drive motor 50 is not operating, the biasing spring 32 is set so as to reduce or reduce the intake flow rate of the intake throttle device 1 of the internal combustion engine. The urging means 30 provided is
The valve shaft 12 can be rotated in the fully closing direction.

Here, as shown in FIG. 1, the biasing means 30
However, it is preferable to include the above-mentioned biasing spring 32 and the biasing spring 31 that biases the valve shaft 12 in the valve opening direction. That is, by using the biasing springs 31 and 32 having different spring constants from each other, the biasing means 30 rotates the valve shaft 12 in terms of the characteristic of the turning torque (so-called biasing torque with respect to the valve shaft opening position). A two-stage characteristic having two stages of torque characteristic inclination with respect to the shaft rotation angle can be obtained. Thus, the inclination of the biasing torque characteristic of the biasing means 30 with respect to the rotation angle can be made variable in consideration of the drive torque characteristic of the drive motor 50. Therefore, the rotation angle control of the valve shaft 12 driven by the drive motor 50 can be facilitated by changing the spring characteristics of the biasing springs 31 and 32 of the biasing means 30 regardless of the driving force of the drive motor 50. it can. Further, since the valve shaft opening degree of the valve shaft 12 can be controlled regardless of the driving force of the drive motor 50, the drive motor 50 can be downsized.

As shown in FIG. 1, the urging means 30 is provided with an intermediate lever 33 which is sandwiched between the urging springs 31 and 32 and guides them.

The biasing means 30 described in this embodiment will be described below.
Is an urging spring (hereinafter referred to as a first spring)
31, an urging spring (hereinafter, referred to as a second spring) 32, and an intermediate lever 33 are included.

The details of the urging means 30 which can prevent the full-close failure at the extremely low temperature which is a feature of the embodiment of the present invention and reduce the drive load of the drive motor in the normal temperature range will be described later. .

The valve body 13 has a well-known valve body shape capable of opening and closing the intake passage 11a in the valve housing 11 by rotating the valve shaft 12 and varying the opening area of the intake passage 11a from the fully closed position to the fully opened position. Have.

The drive motor 50 is provided with an output gear 23 constituting the reduction gear 20 at the end of the drive shaft, and the input gear 21, the output gear 23, and the intermediate gear 22 constituting the reduction gear 20 can mesh with each other. It is geometrically arranged so that it can rotate. The drive motor 50 rotates the valve shaft 12 to which the valve body 13 is fixed, and the opening area of the intake passage 11a can be variably controlled by the control means 60 according to the valve shaft opening position of the valve body 13, The drive motor may be a step motor, a torque motor, or the like other than the DC motor shown in FIG.

As described above, the speed reducer 20 has the structure shown in FIGS.
As shown in FIG. 3, the input gear 21, the output gear 23, and the intermediate gear 22 are included. This speed reducer 20
Includes an input gear 21, an output gear 23, and an intermediate gear 2.
2 is provided with the valve housing 11 and the lid edge portion 70b of the lid 70 is fixed to the valve housing 11 by a fixing member such as a clip 72 shown in FIG. There is. This can prevent the liquid from entering the drive chamber 70a from the outside. The intermediate gear 22 includes a gear portion 22a and a shaft portion 22b, and the gear portion 22a is rotatably supported by the shaft portion 22b.

The valve shaft opening sensor 40 is arranged at one end of the valve shaft 12 together with the input gear 21. For example, a Hall IC is used as the valve shaft opening sensor 40, and a valve of the intake throttle valve 10 is used. Detect the shaft opening.

The control means 60 drives the drive motor 50, and the opening degree of the valve shaft 12, that is, the valve body 1 via the speed reducer 20.
Any electronic control device capable of controlling the opening and closing of 3 may be used, and it is configured as a microcomputer centered on a CPU, a ROM, a RAM and the like (not shown). This control means 60 receives a valve shaft opening signal of the valve shaft opening sensor 40, a signal indicating an operating state of the internal combustion engine such as an accelerator opening signal 91 and an engine speed signal 92, and the like, and outputs the valve shaft. 12
Any device can be used as long as it can control the valve shaft opening position.

The intake throttle device 1 having the above structure is
In a mounted state of a vehicle or the like, air sucked through an air filter (not shown) on the upstream side of intake air is formed in an intake passage 11a formed in a valve housing 11 of an intake throttle valve 10.
Will be introduced to. The introduced intake air has a driving force of the drive motor 50 controlled by the controller 60 and is reduced by the speed reducer 2.
0 to change the valve shaft opening position of the valve body 13 that makes the opening area variable against the urging force of the urging means 30, and according to the valve shaft opening signal detected by the valve shaft opening sensor 40. Then, the intake flow rate is adjusted. This metered intake air is supplied to the intake throttle valve 1
It is led to an internal combustion engine that is arranged airtight on the downstream side of 0, and is mixed with fuel supplied from a fuel injection valve (not shown) in the combustion chamber and ignited.

Here, the intake throttle device 1 of the present invention prevents the full-close failure at extremely low temperatures, and can reduce the driving load of the drive motor in the normal temperature range. 20 has the following features.

First, the speed reducer 20, particularly the input gear 21 provided at one end of the valve shaft 12, faces the fully closed stopper 35 fixed to the housing 11 in the circumferential direction, as shown in FIG. It has a fully closed locking portion 21a that can be mechanically locked at the fully closed position. Thus, when the intermediate gear 22 and the input gear 23 that cooperate with the output gear 21 fixed to the drive motor 50 controlled by the control device 60 are driven to the valve shaft opening position corresponding to the fully closed position, Since the fully closed stopper 35 contacts the fully closed locking portion 21a of the input gear 21, the valve shaft 12 is fixed at the fully closed position.

On the other hand, the opening corresponding to the fully closed state, the so-called default valve shaft opening position near the fully closed state, is in phase with the intermediate lever 33 constituting the urging means 30 and the default stopper 36 having the screwing portion 36a. It is decided by the relationship.

As described above, the urging means 30 includes the first return spring 31, the second return spring 32, and the intermediate lever 33, as shown in FIG. The fully closed stopper 35 and the default stopper 36 are components of the biasing means 30.

As shown in FIG. 1, the intermediate lever 33 is sandwiched between the first return spring 31 and the second return spring 32, and guides each of them, and one of both end portions of the intermediate lever 33 is provided on the valve shaft 12. (For details, valve stem 1
The first spring 31 and the second spring 32 that engage with the input gear 23) fixed to 2 are engaged with one of both ends of the first spring 31. The other of both ends of the second spring 32 is engaged with a temperature sensitive member 39 described later via a spacer 38.

Further, as shown in FIG. 2, the intermediate lever 33 is circumferentially opposed to a default stopper 36 which is screwed into the housing 11 and whose screwing amount can be adjusted from the outside, and mechanically acts as a default valve shaft. It has a default locking portion 33a that can be locked at the opening position.

As a result, when the drive motor 50 is not energized, the valve shaft opening position of the valve shaft 12 can be returned to the default valve shaft opening position, that is, the opening amount corresponding to full closing.

Specifically, in the valve shaft opening range where the valve shaft opening of the intake throttle valve 10 is larger than the default valve shaft opening,
The intermediate lever 33 rotates together with the input gear 31 against the biasing action of the second return spring 32. On the other hand, in a valve shaft opening range where the valve shaft opening of the intake throttle valve 10 is smaller than the default valve shaft opening, the intermediate lever 33 is locked by the default stopper 36 and does not rotate, and the input gear 31, That is, the valve shaft 12 rotates against the first spring 31.

Further, in the embodiment of the present invention, as shown in FIG. 1, the other end of the second spring 32 is inserted through the spacer 38 in the fully closing direction of the valve shaft 12 in accordance with the temperature decrease, in particular. It is engaged with a temperature sensitive member 39 that increases the urging force that urges the valve shaft 12 so as to return to an opening degree corresponding to full closing. The temperature sensitive member 39 is, for example, a spring made of bimetal as shown in FIG. 1, and may be made of a shape memory alloy that changes its shape at a certain specific temperature. The temperature sensitive member 39 is engaged with the second spring 32 through the annular spacer 38 because the second spring 32 is engaged.
This is to ensure the contact of the spring-shaped temperature sensitive member 39 with.

As a result, it is possible to secure the urging force for returning the valve shaft to the fully closed direction in the low temperature range, especially in the extremely low temperature.

Therefore, it is possible to prevent the fully closed return failure at the extremely low temperature and drive motor 50 in the normal temperature range.
Is a biasing means 30 that biases the valve shaft 12 in accordance with the temperature rise.
It is possible to reduce the driving load applied via the valve shaft 12 due to the temperature sensitive member 39 that reduces the biasing force of the valve.

In addition, in the embodiment of the present invention, when the drive motor 50 is not energized, the valve shaft opening position of the valve shaft 12 is returned to the default valve shaft opening position, that is, the opening amount corresponding to full closing. A biasing means 30 including a temperature sensitive member 39 for increasing the biasing force that biases the valve shaft 12 in accordance with the temperature decrease.
When the drive motor 50 is not energized, the default valve shaft position near the fully closed position between the fully opened valve shaft position and the fully closed valve shaft position, that is, the opening amount equivalent to the fully closed condition, regardless of whether the ambient temperature is high or low. It is possible to put it back.

The threaded portion 36 serving as the above-mentioned locking member.
Since the default stopper 36 provided with a can change the screw-in amount from the outside, the default valve shaft opening as the opening equivalent to the fully closed state is set to the required intake flow rate for each internal combustion engine equipped with the intake throttle device 1. It is possible to make it variable.

Here, the operation of the valve shaft 12 of the intake throttle device of the present embodiment, the biasing means 30, especially the intermediate lever 33, and the first and second springs 31, 32 are applied depending on the ambient temperature. The relationship with the temperature sensitive member 39 that makes the urging force of the urging means 30 variable will be described below with reference to FIGS.

FIG. 3 shows the intake throttle valve 10 and the intake throttle valve 10.
Motor for driving the valve shaft 12 and the biasing means 30
Fig. 3 schematically shows an operating state according to the valve shaft opening degree of
3A is a substantially fully closed state, FIG. 3B is a valve open state at a substantially default valve shaft position, and FIG. 3C is a fully closed state in which the valve shaft opening is larger than the default valve shaft position. Represents a smaller valve shaft opening. Urging means 30 in FIG.
In particular, the intermediate lever 33, and the first spring 31 and the second spring 32 schematically move in the opening direction and the closing direction of the valve body 13 by moving in the arrow direction in the figure, that is, in the left-right direction. .

In the substantially fully closed state of FIG. 3A, the fully closed stopper portion 35 of the input gear 21 comes into contact with the fully closed stopper 35.
Further, in the intermediate lever 33 with which the first spring 31 and the second spring 32 are engaged, the default locking portion 33 a of the intermediate lever 33 is in contact with the default stopper 36.

It should be noted that the opening θ ₀ (see FIG. 4) from the fully closed valve shaft opening position to the default valve shaft opening position is set in the left-right direction of the intermediate lever 33 and the input gear 21 for convenience in FIG. Expressed with a predetermined gap.

In the substantially fully closed state of FIG. 3A, since the intermediate lever 33 is in contact with the default stopper 36,
Even if the ambient temperature changes and the temperature sensitive member 39 deforms in the left-right direction, the urging force applied to the valve shaft 12 does not change (see FIG. 4).

Next, in the valve open state of the substantially default valve shaft position of FIG. 3B, the valve shaft opening of the valve shaft 12 reaches substantially θ ₀ , so that the intermediate lever 33 and the input gear 21 are left and right. The predetermined gap in the direction becomes substantially zero, and immediately before the intermediate lever 33 is released from the locking or engagement of the default stopper 36. Here, the intermediate lever 33 is in a state where the default locking portion 33 a of the intermediate lever 33 is in contact with the default stopper 36.

Even in the valve open state at the substantially default valve shaft position of FIG. 3B, the intermediate lever 33 has the default stopper 36.
Therefore, the urging force applied to the valve shaft 12 does not change even if the ambient temperature changes and the temperature sensitive member 39 deforms in the left-right direction (see FIG. 4).

Further, when the valve shaft opening of the valve shaft 12 is made larger than the default valve shaft position, the intermediate lever 33 and the first spring 31 are integrated as shown in FIG.
2 rotates together with the intermediate lever 33 against the second spring 32.

Therefore, when the ambient temperature changes and the temperature sensitive member is deformed in the left-right direction, as shown in FIG. 3C, for example, the urging force in the right direction in the figure increases as the ambient temperature decreases. If the bimetal temperature sensitive member 39 is deformed in the direction, the biasing force can be increased to the biasing torque characteristic shown by the alternate long and short dash line in FIG.

Therefore, according to the embodiment of the present invention having the above-mentioned structure, in order to prevent the fully closed return failure at the extremely low temperature,
The opening corresponding to the fully closed state, that is, the biasing force for returning to the default valve shaft opening surely increases (see Ce indicated by the one-dot chain line in FIG. 4).
(State of L), in the normal temperature range, due to the temperature sensitive member 39 that reduces the biasing force of the biasing means 30 that biases the valve shaft 12 in response to the temperature rise, the drive motor 50 is driven via the valve shaft 12. It is possible to reduce the driving load applied to (the state of CeH shown by the solid line in FIG. 4).

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view showing a configuration of an intake throttle device according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of the intake throttle device of FIG. 1 viewed from a direction II inside a cover.

FIG. 3 is a schematic diagram showing a relationship relating to the operation of the valve shaft of the intake throttle device of the present embodiment, the urging means, particularly the intermediate lever, and the first and second springs.
Is a substantially fully closed state, FIG. 3 (b) is a valve open state at a substantially default valve shaft position, and FIG. 3 (c) is a valve shaft opening larger than the default valve shaft position and smaller than a fully closed state. It is a schematic diagram showing the state of a valve shaft opening degree.

FIG. 4 is a graph showing torque characteristics of the biasing means according to the valve shaft opening of the intake throttle device of the present embodiment in FIG.
Point a is a torque value in the valve shaft opening state relating to FIG. 3 (a), point b is a torque value in the valve shaft opening state relating to FIG. 3 (c), and point c is the torque value in FIG. 3 (c). 5 is a graph showing a torque value at a valve shaft opening degree related to the above.

[Description of Reference Signs] 1 intake throttle device 10 intake throttle valve 11 valve housing 11a intake passage 12 valve shaft 13 valve body 19a, 19b bearing member 20 reduction gears 21, 22, 23 input gear, intermediate gear, output gear 21a fully closed Stop portion 30 Biasing means 31, 32 First biasing spring, second spring 33 Intermediate lever (first and second biasing springs 31,
32a) Default locking part 35 Full-closed stopper 36 Default stopper 36a Default stopper 36a Threaded part 38 Spacer 39 Temperature sensitive member 40 Valve shaft opening sensor 50 Drive motor 60 Control means 70 Lid θ Valve shaft opening θ ₀ Default valve Shaft opening position

Claims (4)

[Claims] 1. An internal combustion engine comprising: an intake throttle valve that opens and closes an intake passage; a drive motor that drives a valve shaft of the intake throttle valve; and a biasing means that biases the valve shaft in a valve closing direction. In the intake throttle device, the urging means includes a temperature sensitive member at one end of a return spring engaged with the valve shaft, the temperature responsive member changing the urging force urging the valve shaft according to a temperature change. An intake throttle device for an internal combustion engine. 2. The biasing means pivots the valve shaft to a default valve shaft position near a fully closed position intermediate between a fully opened valve shaft position and a fully closed valve shaft position when the drive motor is not energized. The intake throttle device for an internal combustion engine according to claim 1, wherein the intake throttle device is provided. 3. Rotating the valve shaft to the default valve shaft position near the fully closed means that the spring of the biasing means includes a first spring, a second spring, and the first spring. An intermediate lever that is sandwiched between a spring and the second spring and is rotatable around the valve shaft is provided, and one end of the first spring is attached to the valve shaft,
The other engages with the intermediate lever, and both ends of the second spring have one engaged with the intermediate lever and the other engaged with the temperature sensitive member, and when the drive motor is not energized, When returning from the fully opened to the fully closed valve shaft position, the intermediate lever contacts the default locking member, so that the valve shaft is locked at the valve shaft position near the fully closed position. Claim 2
An intake air throttle device for an internal combustion engine according to. 4. The default locking member is provided with a screwing portion that can be screwed, and the default valve shaft position can be changed according to the amount of screwing from the outside. Intake throttle device for internal combustion engine.