JP4471918B2 - Throttle valve device - Google Patents

Description

  The present invention relates to a throttle valve device that adjusts the amount of air taken into an engine (intake air amount).

[Conventional technology]
2. Description of the Related Art Conventionally, a throttle valve device that adjusts the amount of intake air includes a throttle valve that opens and closes a passage (intake air passage) of air sucked into an engine, and a speed reduction mechanism that transmits driving force from an actuator such as an electric motor to the throttle valve. And a biasing means for returning the throttle valve to a fully closed state, and a body for rotatably supporting and accommodating the throttle valve.

  In this throttle valve device, the control amount for driving the actuator (for example, the energization amount to the electric motor) is electronically controlled according to the operation amount of the accelerator pedal by the driver. As a result, the actual opening of the intake air passage is substantially matched with the target opening according to the operating state, and the intake air amount is adjusted so as to substantially match the target amount.

  By the way, the speed reduction mechanism of the throttle valve device includes an intermediate shaft connected to the body and an intermediate gear that is rotatably attached to the intermediate shaft and transmits a driving force from the actuator to the throttle valve (for example, Patent Documents). 1).

  Here, the connection state of the intermediate shaft 101 and the body 102 in the conventional throttle valve device is shown in FIG. A connecting portion 103 connected to the intermediate shaft 101 protrudes from the body 102 in the axial direction. As shown in FIG. 5B, the connecting portion 103 is provided with a fitting hole 104 into which the intermediate shaft 101 is fitted in the axial direction. Press-fitted and connected.

[Problems with conventional technology]
However, since the body 102 is a resin molded product, the diameter (hole diameter) of the fitting hole 104 also varies with the variation in solidification shrinkage during molding. For this reason, a product in which the difference between the diameter of the intermediate shaft 101 (shaft diameter) and the hole diameter is increased (hereinafter, the difference between the shaft diameter and the hole diameter is referred to as press-fit tightening allowance).

When the press-fit tightening allowance is large, the stress generated in the connection portion 103 increases, and there is a high possibility that resin cracking or creep will occur. For this reason, the holding force of the intermediate shaft 101 by the connecting portion 103 is reduced, and the coaxiality between the intermediate shaft 101 and the output shaft of the actuator and the valve shaft of the throttle valve may not be maintained.
JP 2003-206762 A

  The present invention has been made to solve the above-described problems, and an object of the present invention is to reduce the stress generated when the intermediate shaft is connected to the body in the throttle valve device, and to output the intermediate shaft and the output shaft of the actuator. Another object of the present invention is to provide a structure capable of maintaining the coaxiality with the valve shaft of the throttle valve.

[Means of Claim 1]
The throttle valve device according to claim 1 is a throttle valve that opens and closes an intake air passage, a speed reduction mechanism that transmits a driving force from a predetermined actuator to the throttle valve, and a body that rotatably supports and accommodates the throttle valve. With. The reduction mechanism has an intermediate shaft connected to the body, and an intermediate gear that is rotatably attached to the intermediate shaft and transmits a driving force from the actuator to the throttle valve. And the connection part of the intermediate shaft provided in the body is provided with a fitting hole into which the intermediate shaft is fitted, and a gap in which the outer peripheral surface of the fitted intermediate shaft is exposed.

  Thereby, when the intermediate shaft is connected to the body, the hole diameter can be enlarged due to the presence of the gap. That is, stress generated when the intermediate shaft is connected to the body can be released to the gap and reduced. For this reason, it is possible to reduce the possibility of resin cracking or creep due to stress, and to prevent the holding force of the intermediate shaft by the connecting portion from being reduced. As a result, even if the press-fit tightening allowance is large, the coaxiality between the intermediate shaft and the output shaft of the actuator and the valve shaft of the throttle valve can be maintained.

In addition, the direction in which the outer peripheral surface of the intermediate shaft is exposed to the gap is the direction of the load (driving load) applied to the intermediate shaft when the driving force is transmitted from the actuator to the throttle valve, and the axis of the intermediate shaft. It is perpendicular to the direction.
As a result, the inner peripheral surface of the connection portion that forms the fitting hole and the outer peripheral surface of the intermediate shaft abut in the load direction of the drive load, and the drive load applied to the intermediate shaft is reliably received by the connection portion. For this reason, it is possible to prevent the intermediate shaft from falling due to the driving load.

[Means of claim 2 ]
According to the throttle valve device of the second aspect, the outer peripheral surface of the connecting portion is provided with ribs in the load direction of the driving load.
Thereby, a connection part is reinforced in the load direction of a driving load. For this reason, the possibility of deformation or breakage of the connecting portion due to the load of the driving load can be reduced.

[Means of claim 3 ]
According to the throttle valve device of the third aspect , the adhesive is interposed between the outer periphery of the intermediate shaft and the inner periphery of the connecting portion.
When the load of the driving load on the intermediate shaft is intermittently repeated, heating and cooling are repeated at the connection portion. As a result, at the connecting portion, the resin is repeatedly softened and cured, and the holding force of the intermediate shaft by the connecting portion may be reduced.
In contrast, by interposing an adhesive between the outer periphery of the intermediate shaft and the inner periphery of the connecting portion, the intermediate shaft can be held even if the holding force of the connecting portion itself is reduced.
Alternatively, the molding conditions of the body can be set in advance so that the hole diameter is larger than the shaft diameter, and the position of the intermediate shaft can be determined by an adhesive.

The throttle valve device of the best mode 1 includes a throttle valve that opens and closes an intake air passage, a speed reduction mechanism that transmits a driving force from a predetermined actuator to the throttle valve, and a body that rotatably supports and accommodates the throttle valve. Is provided. The reduction mechanism has an intermediate shaft connected to the body, and an intermediate gear that is rotatably attached to the intermediate shaft and transmits a driving force from the actuator to the throttle valve. And the connection part of the intermediate shaft provided in the body is provided with a fitting hole into which the intermediate shaft is fitted, and a gap in which the outer peripheral surface of the fitted intermediate shaft is exposed.
The direction in which the outer peripheral surface of the intermediate shaft is exposed to the air gap is perpendicular to the load direction of the driving load applied to the intermediate shaft when the driving force is transmitted from the actuator to the throttle valve and the axial direction of the intermediate shaft. It is.
Furthermore, ribs are provided on the outer peripheral surface of the connecting portion in the load direction of the driving load .

[Configuration of Example ]
A configuration of the throttle valve device 1 of the embodiment will be described with reference to FIGS. 1 and 2.
The throttle valve device 1 is a device that adjusts the amount of air (intake air amount) taken into an engine (not shown). As shown in FIG. 1, the throttle valve device 1 generates a throttle valve 2 that opens and closes a passage of air taken into the engine (intake air passage: not shown), and a driving force that rotationally drives the throttle valve 2. An actuator 3 such as an electric motor to be driven, a speed reduction mechanism 4 for transmitting a driving force from the actuator 3 to the throttle valve 2, an urging means (not shown) for returning the throttle valve 2 to a fully closed state, and turning the throttle valve 2. And a body 5 that is supported and accommodated movably.

  In this throttle valve device 1, the control amount for driving the actuator 3 (for example, the energization amount to the electric motor) is electronically controlled according to the operation amount of the accelerator pedal by the driver. As a result, the actual opening of the intake air passage is substantially matched with the target opening according to the operating state, and the intake air amount is adjusted so as to substantially match the target amount.

  The throttle valve 2 is a butterfly valve having a circular plate-like valve body (not shown) and a valve shaft 7 provided at the center of the valve body. A valve shaft side gear 8 that receives a driving force from the speed reduction mechanism 4 is attached to one end of the valve shaft 7.

  The actuator 3 is, for example, a known electric motor, and one end portion of the output shaft 10 protrudes from a main body (not shown) of the electric motor. An output shaft side gear 11 that transmits driving force to the speed reduction mechanism 4 is attached to one end of the output shaft 10.

  The speed reduction mechanism 4 includes an intermediate shaft 13 connected to the body 5 and an intermediate gear 14 that is rotatably attached to the intermediate shaft 13 and transmits a driving force from the actuator 3 to the throttle valve 2. The intermediate shaft 13 is a metallic rod-like member that is fitted to the body 5 as shown in FIGS. As shown in FIG. 1, the intermediate gear 14 includes a large-diameter gear 15 that meshes with the output shaft-side gear 11, and a small-diameter gear 16 that has a smaller diameter than the large-diameter gear 15 and meshes with the valve-shaft side gear 8. The intermediate gear 14 freely rotates with respect to the intermediate shaft 13, whereby the rotational speed of the output shaft side gear 11 is reduced and transmitted to the valve shaft side gear 8, and the drive obtained from the output shaft 10 is obtained. The force is amplified and transmitted to the valve shaft 7.

  The biasing means is, for example, a spring that is arranged coaxially with the valve shaft 7 and biases the throttle valve 2 toward the fully closed state in the rotational direction of the throttle valve 2.

  As shown in FIG. 2, the body 5 is a resin having an output shaft protruding hole 18 from which the output shaft 10 protrudes, a valve shaft protruding hole 19 from which the valve shaft 7 protrudes, and a fitting hole 20 into which the intermediate shaft 13 is fitted. It is a molded product. The fitting hole 20 is formed in a connecting portion 21 protruding in the axial direction. The connecting portion 21 is provided for connecting the intermediate shaft 13 to the body 5. The output shaft projecting hole 18, the valve shaft projecting hole 19 and the fitting hole 20 include the shaft center a of the output shaft 10, the shaft center b of the valve shaft 7 and the shaft center c of the intermediate shaft 13 in one plane α. Is provided. The intermediate shaft 13 is connected to the fitting hole 20 by cold press fitting.

[Features of Examples ]
The features of the throttle valve device 1 of the embodiment will be described with reference to FIG.
The connection portion 21 is provided with a gap 24 through which the outer peripheral surface of the intermediate shaft 13 is exposed when the intermediate shaft 13 is fitted into the fitting hole 20. The gap 24 is provided in a slit shape in the same direction as the fitting hole 20. Further, the direction in which the outer peripheral surface of the intermediate shaft 13 is exposed to the gap 24 (exposure direction) is the load direction of the driving load applied to the intermediate shaft 13 when the driving force is transmitted from the actuator 3 to the throttle valve 2. And a direction perpendicular to the axial direction of the intermediate shaft 13.

  Here, the load direction of the drive load is a direction perpendicular to the plane α. That is, the driving load is applied to the intermediate shaft 13 by a driving force applied from the output shaft side gear 11 to the intermediate gear 14 and a driving resistance force applied from the valve shaft side gear 8 to the intermediate gear 14. When the axes a to c are included in one plane α, the driving force applied to the intermediate gear 14 and the driving resistance force exerted on the intermediate gear 14 are perpendicular to the plane α as shown in FIG. Apply load in any direction. Therefore, the load direction of the driving load is a direction perpendicular to the plane α.

  Furthermore, the outer peripheral surface of the connection part 21 is provided with a rib 30 in the load direction of the driving load, and the connection part 21 and the part of the body 5 other than the connection part 21 are bridged.

(Effects of Example )
The operation of the throttle valve device 1 according to the embodiment will be described with reference to FIGS. 1 and 2.
First, when the intermediate shaft 13 is connected to the connection portion 21 by cold press-fitting, the hole diameter depends on the difference (press-fit tightening allowance) between the diameter of the intermediate shaft 13 and the diameter (hole diameter) of the fitting hole 20. , Due to the presence of the gap 24. That is, when the intermediate shaft 13 is connected to the connecting portion 21 by cold press fitting, stress is generated in the connecting portion 21 according to the press fitting tightening allowance. And this stress is released to the space | gap 24 with the expansion of a hole diameter, and is reduced.

  Further, when the output shaft side gear 11 is rotated and a driving force is applied to the intermediate gear 14, a driving resistance force is exerted from the valve shaft side gear 8 to the intermediate gear 14. Thereby, a driving load is applied to the intermediate gear 14 from both the driving force and the driving resistance force in the load direction shown in FIG. For this reason, a driving load corresponding to the resultant force of the driving force and the driving resistance force is applied to the intermediate shaft 13 in the load direction shown in FIG. As a result, the inner peripheral surface forming the fitting hole 20 and the outer peripheral surface of the intermediate shaft 13 abut on each other in the load direction of the driving load, so that the driving load applied to the intermediate shaft 13 is received by the connecting portion 21.

[Effects of Examples ]
According to the throttle valve device 1 of the embodiment, the connection portion 21 connected to the intermediate shaft 13 exposes the fitting hole 20 into which the intermediate shaft 13 is fitted and the outer peripheral surface of the fitted intermediate shaft 13. An air gap 24 is provided.
Thereby, when the intermediate shaft 13 is connected to the body 5, the hole diameter can be enlarged due to the presence of the gap 24. That is, the stress generated when the intermediate shaft 13 is connected to the body 5 can be released to the gap 24 and reduced. For this reason, it is possible to reduce the possibility of resin cracking or creep due to stress, and to prevent the holding force of the intermediate shaft 13 by the connecting portion 21 from being reduced. As a result, even if the press-fit tightening allowance is large, the coaxiality between the intermediate shaft 13 and the output shaft 10 of the actuator 3 and the valve shaft 7 of the throttle valve 2 can be maintained.

Further, the direction in which the outer peripheral surface of the intermediate shaft 13 is exposed to the gap 24 is perpendicular to the load direction of the driving load and the axial direction of the intermediate shaft 13.
As a result, the inner peripheral surface of the connecting portion 21 and the outer peripheral surface of the intermediate shaft 13 come into contact with each other in the driving load direction, and the driving load loaded on the intermediate shaft 13 is reliably received by the connecting portion 21. For this reason, it is possible to prevent the intermediate shaft 13 from falling due to the driving load.

Further, a rib 30 is provided on the outer peripheral surface of the connecting portion 21 in the load direction of the driving load.
Thereby, the connection part 21 is reinforced in the load direction of a drive load. For this reason, the possibility of deformation or breakage of the connection portion 21 due to the load of the driving load can be reduced.

According to the throttle valve device 1 of the reference example 1 , as shown in FIG. 3, the tap 26 is provided on the outer peripheral surface on one end side of the intermediate shaft 13. The intermediate shaft 13 is screwed to the connection portion 21.
Thereby, even if the intermediate shaft 13 is connected to the connection portion 21, no stress is generated. For this reason, the possibility of resin cracking and creep due to stress can be eliminated.

According to the throttle valve device 1 of the reference example 2 , as shown in FIG. 4, a stepped portion 27 is provided on the outer periphery of the intermediate shaft 13 to regulate the progress of the connection to the connecting portion 21. The tap 26 is provided on one end side with respect to the step portion 27.
Thereby, the protrusion amount at the time of connecting the intermediate shaft 13 to the connection part 21 can be determined easily, without adjusting.

[Modification]
In the throttle valve device 1 of the embodiment, an adhesive may be applied to the outer peripheral surface of the intermediate shaft 13, and the adhesive may be interposed between the outer periphery of the intermediate shaft 13 and the inner periphery of the connection portion 21.

When the load of the driving load on the intermediate shaft 13 is intermittently repeated as the throttle valve device 1 is actually driven, heating and cooling are repeated at the connecting portion 21. As a result, in the connection part 21, the softening and curing of the resin are repeated, and there is a high possibility that the holding force of the intermediate shaft 13 by the connection part 21 is reduced.
In contrast, by interposing an adhesive between the outer periphery of the intermediate shaft 13 and the inner periphery of the connection portion 21, even if the holding force of the connection portion 21 itself is reduced, the intermediate shaft 13 is held by the adhesive. can do.

  Alternatively, the molding conditions of the body 5 may be set in advance so that the hole diameter is larger than the diameter of the intermediate shaft 13, and the position of the intermediate shaft 13 can be determined by an adhesive.

It is a front view of a throttle valve device ( example) . (A) is a front view of the body to which the intermediate shaft is connected, (b) is an explanatory view showing the connecting direction of the intermediate shaft to the connecting portion, and (c) is a connection state between the intermediate shaft and the connecting portion. It is explanatory drawing shown ( Example) . It is explanatory drawing which shows the connection state of an intermediate shaft and a connection part ( reference example 1 ). It is explanatory drawing which shows the connection state of an intermediate shaft and a connection part ( reference example 2 ). (A) is a front view of the body to which the intermediate shaft is connected, (b) is an explanatory view showing the connecting direction of the intermediate shaft to the connecting portion, and (c) is a connection state between the intermediate shaft and the connecting portion. It is explanatory drawing shown (conventional example).

First throttle valve device 2 the throttle valve 3 actuator 4 reduction mechanism 5 body 13 intermediate shaft 14 intermediate gear 21 connecting portion 24 air-gap
30 ribs

Claims (3)

A throttle valve that opens and closes the passage of air taken into the engine;
A speed reduction mechanism for transmitting a driving force from a predetermined actuator to the throttle valve;
In a throttle valve device comprising a body that rotatably supports and accommodates the throttle valve,
The speed reduction mechanism includes an intermediate shaft connected to the body, and an intermediate gear that is rotatably attached to the intermediate shaft and transmits a driving force from the actuator to the throttle valve.
The connecting portion of the intermediate shaft provided in the body is provided with a fitting hole into which the intermediate shaft is fitted, and a gap in which an outer peripheral surface of the fitted intermediate shaft is exposed ,
The direction in which the outer peripheral surface of the intermediate shaft is exposed to the gap is the load direction of the load applied to the intermediate shaft when driving force is transmitted from the actuator to the throttle valve, and the axis of the intermediate shaft A throttle valve device characterized by being perpendicular to a direction . The throttle valve device according to claim 1,
A throttle valve device , wherein a rib is provided on an outer peripheral surface of the connecting portion in a load direction of a load applied to the intermediate shaft when a driving force is transmitted from the actuator to the throttle valve. . The throttle valve device according to claim 1 or 2,
A throttle valve device , wherein an adhesive is interposed between an outer periphery of the intermediate shaft and an inner periphery of the connection portion .

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