JP7616922B2 - Transmission mechanism and fluid control valve - Google Patents

Description

The present invention relates to a transmission mechanism and a structure of a fluid control valve equipped with a transmission mechanism.

For example, in recent years, electric throttle valves have come to be widely used in throttle valves that control the amount of intake air in internal combustion engines. Most electric throttle valves have an electric motor, reduction mechanism, and throttle valve built into the body.

Patent Document 1 discloses an example of an electric throttle valve. In the electric throttle valve disclosed in Patent Document 1, a throttle shaft that drives a valve body and a drive shaft of an electric motor (motor output shaft) are arranged in parallel within a body, and a reduction mechanism is arranged between the motor output shaft and the throttle shaft. The reduction mechanism is composed of a motor gear fixed to the motor output shaft, an intermediate shaft fixed to the body and arranged in parallel to the motor output shaft and the throttle shaft, an intermediate gear rotatably supported by the intermediate shaft, and a throttle gear (valve gear) fixed to the valve shaft. The intermediate gear is formed with a first intermediate gear that meshes with the motor gear and a second intermediate gear that meshes with the throttle gear.

Patent No. 6419344

In the electric throttle valve of Patent Document 1, the first intermediate gear and the second intermediate gear are offset from each other at different positions in the axial direction (the vertical direction on the paper of Figures 1 and 2 of Patent Document 1).

As a result, when the intermediate gear is driven, it receives radial forces from the motor gear and from the throttle gear in opposite directions at different axial positions, causing it to tilt.

When the intermediate gear tilts in this way, there is a possibility that the outer peripheral end at the axial end of the intermediate gear may come into contact with the opposing part of the body, i.e., the support part of the intermediate shaft, causing friction in the rotation of the intermediate shaft and potentially shortening the life of the reduction mechanism and motor.

The present invention was made in consideration of these problems, and its purpose is to provide a speed change mechanism that suppresses the increase in friction caused by the inclination of the intermediate gear, and a fluid control valve equipped with the speed change mechanism.

To achieve the above object, the speed change mechanism of the present invention is a speed change mechanism that transmits a rotational driving force from an input shaft arranged parallel to a support member to an output shaft, and is characterized in that it comprises an intermediate shaft fixed to the support member and arranged parallel to the input shaft and the output shaft, an input gear fixed to the input shaft, an output gear fixed to the output shaft, and an intermediate gear rotatably supported on the intermediate shaft, the intermediate gear has a first intermediate gear that meshes with the input gear and a second intermediate gear that meshes with the output gear, the first intermediate gear and the second intermediate gear are located at different positions in the axial direction of the intermediate shaft, a hemispherical recess is formed in the intermediate gear with the axis of the intermediate shaft as the center, and a protrusion is formed in the intermediate shaft that is at least hemispherical with the axis of the intermediate shaft as the center and is inserted into the recess.

Preferably, the recess is provided inside the intermediate gear, and the recess is placed on the protrusion, so that the intermediate gear is supported on the intermediate shaft.

Also, preferably, the curvature of the recess is smaller than the curvature of the protrusion.

The fluid control valve of the present invention is characterized in that the input shaft is a drive shaft of a motor, the output shaft is a valve shaft that drives a valve body, the support member is provided in a case that supports the motor and the valve shaft, and has a speed change mechanism that is a reduction mechanism that reduces the speed of the rotation of the drive shaft of the motor, increases the drive torque, and transmits it to the valve shaft.

Also, preferably, the fluid control valve is a throttle valve that controls the intake flow rate of an internal combustion engine.

According to the reduction mechanism of the present invention, the intermediate gear is rotatably supported on the intermediate shaft by inserting a hemispherical convex portion into a hemispherical concave portion. Therefore, even if the intermediate gear is tilted when the intermediate gear rotates due to the rotation of the input shaft, the convex portion and the concave portion slide smoothly, reducing friction between the concave portion and the convex portion. In addition, by transmitting the driving force of the motor to the valve shaft via this reduction mechanism, a fluid control valve with excellent responsiveness and a long life can be obtained.

1 is a side view of an electric throttle valve according to an embodiment of the present invention; FIG. 2 is a top view of the electric throttle valve with the cover removed. FIG. 2 is a vertical cross-sectional view of the upper part of the electric throttle valve. FIG. 2 is an enlarged vertical cross-sectional view of the vicinity of an intermediate shaft of the electric throttle valve. 5 is an explanatory diagram of the direction of a force that an intermediate gear receives when the motor is driven. FIG.

Below, one embodiment of the present invention will be described with reference to the drawings.

Figure 1 is a side view of an electric throttle valve 10 (fluid control valve) according to one embodiment of the present invention. Figure 2 is a top view of the electric throttle valve 10 with the cover 11 removed. Figure 3 is a vertical cross-sectional view of the upper part of the electric throttle valve 10. Figure 4 is an enlarged cross-sectional view of the electric throttle valve 10 near the intermediate shaft 36.

FIG. 3 is a cross-sectional view of the upper part of the electric throttle valve 10 cut vertically, more specifically, cut along a plane including the axes of the motor shaft 13 (input shaft), the valve shaft 35 (output shaft), and the intermediate shaft 36 (intermediate shaft) described below. The electric throttle valve 10 of the present embodiment described below is arranged so that the motor shaft 13 extends in the vertical direction and the reduction mechanism 20 described below is located above.

The electric throttle valve 10, which is one embodiment of the present invention, is a fluid control valve that controls the intake flow rate of an internal combustion engine mounted on, for example, an automobile.

As shown in Figures 1 to 3, the electric throttle valve 10 includes a valve body 16 (case) in which an intake passage 15 (fluid passage) is formed, a valve 17 (valve body) that opens and closes the intake passage 15 to adjust the flow passage cross-sectional area, and an electric motor 12 that drives the valve 17.

The valve body 16 has an upper body 21 in which an accommodation space 19 is formed to house the electric motor 12, and a lower body 22 in which an intake passage 15 is formed and in which a valve 17 is provided, and is configured by fastening the upper body 21 and lower body 22 to each other with bolts 23.

An opening 25 is provided at the top of the upper body 21 facing the storage space 19, and the opening 25 is covered by a cover 11.

The cover 11 is also provided with wiring for supplying power to the electric motor 12 and a connector 30 for connecting wiring to an external device such as a rotation angle sensor (not shown). The connector 30 is located on top of the electric motor 12.

As shown in FIG. 3, the reduction gear mechanism 20 and the electric motor 12 are housed in the storage space 19 between the upper body 21 and the cover 11.

The motor shaft 13, which is the drive shaft of the electric motor 12, and the valve shaft 35 (output shaft) that drives the valve 17 extend vertically and are arranged parallel to each other. The upper ends of the motor shaft 13 and the valve shaft 35 are arranged so that they face the opening 25 of the upper body 21. In other words, the opening 25 of the upper body 21 opens in the extension direction of the upper end of the motor shaft 13.

Between the motor shaft 13 and the valve shaft 35, there is provided an intermediate shaft 36 (intermediate shaft) that is fixed to the upper body 21 and the cover 11 and extends vertically in parallel with the motor shaft 13 and the valve shaft 35.

The reduction mechanism 20 is composed of a motor gear 37 (input gear) fixed to the upper end of the motor shaft 13, an intermediate shaft 36, an intermediate gear 38 rotatably supported on the intermediate shaft 36, and a valve gear 39 (output gear) fixed to the upper end of the valve shaft 35.

The intermediate gear 38 has a first intermediate gear 41 that meshes with the motor gear 37 and a second intermediate gear 42 that meshes with the valve gear 39, and the first intermediate gear 41 and the second intermediate gear 42 are arranged vertically, i.e., connected in the axial direction of the intermediate shaft 36, and are integrally configured.

The reduction mechanism 20 transmits the rotational driving force of the electric motor 12 from the motor shaft 13 through the motor gear 37, the first intermediate gear 41, the second intermediate gear 42, and the valve gear 39 to the valve shaft 35 while reducing the speed, thereby driving and rotating the valve 17 to open and close.

The upper body 21 is provided with a return spring (not shown). The return spring rotates the valve shaft 35 relative to the upper body 21, biasing the valve 17 to, for example, a predetermined intermediate opening state. Therefore, when the electric motor 12 is deactivated, the electric throttle valve 10 has the valve 17 in a predetermined intermediate opening state, and by operating the electric motor 12, the valve 17 is opened or closed from the predetermined intermediate opening.

Of the intermediate gears 38, the first intermediate gear 41 is positioned close to the electric motor 12, and the second intermediate gear 42 is positioned on the cover 11 side. Therefore, the motor gear 37 is positioned close to the electric motor 12 by aligning its vertical axial position with the first intermediate gear 41, and the valve gear 39 is positioned far from the valve 17 by aligning its vertical axial position with the second intermediate gear 42.

As shown in FIG. 4, the intermediate gear 38 has a hole 40 at its axial center, into which the intermediate shaft 36 is inserted. Furthermore, the intermediate shaft 36 has a protrusion 51 at its axially middle position, which rotatably supports the intermediate gear 38.

The protrusion 51 is located inside the intermediate gear 38 when the intermediate gear 38 is supported by the intermediate shaft 36, and protrudes radially outward in a spherical shape from the outer circumferential surface of the intermediate shaft 36.

Meanwhile, the intermediate gear 38 is provided with a recess 52 that contacts the protrusion 51 inside. The recess 52 is formed so as to be recessed upward. In other words, the hole 40 of the intermediate gear expands in diameter below the recess 52, forming a smooth step at the recess 52. The recess 52 is placed on the upper half of the protrusion 51, restricting the intermediate gear 38 from moving downward in the axial direction of the intermediate shaft 36, and the intermediate gear 38 is rotatably supported by the intermediate shaft 36.

The curvature of the recess 52 is slightly smaller than that of the protrusion 51, i.e., the recess 52 has a gentler curve than the protrusion 51. Therefore, the intermediate gear 38 is supported so that the recess 52 and the protrusion 51 are in surface contact in a substantially circular band shape, or at least in line contact in a circular shape.

The lower end of the intermediate gear 38 is provided with an intermediate gear chamfered portion 55, which is chamfered in an arc shape so that the outer periphery of the hole 40 is recessed upward, for example. On the other hand, the upper body 21 is provided with a cylindrical support portion 56 (support member). The outer periphery of the upper end of the support portion 56 is formed with a support portion chamfered portion 57, which is chamfered in an arc shape, for example. The intermediate gear chamfered portion 55 and the support portion chamfered portion 57 are formed to face each other with approximately the same shape. When the recessed portion 52 and the protruding portion 51 come into contact with each other and the intermediate gear 38 is supported by the intermediate shaft 36, and the intermediate gear 38 and the intermediate shaft 36 are positioned coaxially, or even when the intermediate gear 38 is tilted, the intermediate gear chamfered portion 55 and the support portion chamfered portion 57 are set to be separated from each other.

Figure 5 is an explanatory diagram of the direction of the force that the intermediate gear 38 receives when the motor is driven.

With the above-described configuration, in the reduction mechanism 20 of the electric throttle valve 10 of this embodiment, by driving the electric motor 12 and rotating the motor shaft 13, the intermediate gear 38 receives a rotational force from the motor gear 37 and also receives a reaction force to the rotational force from the valve gear 39. At this time, as shown in Figure 5, radial forces F1, F2 received by the intermediate gear 38 act in opposite directions toward the axis at different positions in the axial direction of the intermediate shaft 36. In detail, the meshing position between the motor gear and intermediate gear 38 and the meshing position between the valve gear 39 and intermediate gear 38 differ in the axial distance of the intermediate shaft 36 (the vertical height on the paper surface of FIG. 5) based on the contact surface between the recess 55 of the intermediate gear 38 and the protrusion 57 of the support portion 56, and radial forces F1 and F2 act on the intermediate gear 38 in opposite directions, so that when the intermediate gear 38 rotates, the intermediate gear 38 tilts slightly on a plane passing through the axis due to these radial forces F1 and F2.

In this embodiment, the intermediate gear 38 is rotatably supported by the intermediate shaft 36 with a hemispherical recess 52 formed inside the intermediate gear 38 in contact with the upper portion of the spherical protrusion 51 formed on the intermediate shaft 36. Therefore, even if the intermediate gear 38 is tilted, the protrusion 51 and the recess 52 slide smoothly, reducing friction (frictional force) between the recess 52 and the protrusion 51. Therefore, since friction in the reduction mechanism 20 is reduced when the electric motor 12 is driven to rotate, the responsiveness of the opening and closing drive of the valve 17 in the electric throttle valve 10 can be improved, and the life of the electric motor 12 and the reduction mechanism 20 can be extended.

In addition, the recess 52 of the intermediate gear 38 is recessed upward, and the upper surface of the protrusion 51 of the intermediate shaft 36 is inclined downward toward the radially outward direction. Therefore, even if foreign matter or the like gets between the recess 52 and the protrusion 51, it slides radially outward from the upper surface of the protrusion 51 and is easily discharged from between the recess 52 and the protrusion 51. This prevents foreign matter or the like from accumulating between the recess 52 and the protrusion 51, and maintains the sliding performance between the recess 52 and the protrusion 51.

Furthermore, since the curvature of the recess 52 is smaller than that of the protrusion 51, the size of the gap between the recess 52 and the protrusion 51 increases radially outward. This makes it easier to expel foreign matter that has entered between the recess 52 and the protrusion 51 radially outward.

In addition, an intermediate gear chamfered portion 55 is formed on the outer peripheral edge of the hole portion 40 at the lower end of the intermediate gear 38, and a support portion chamfered portion 57 of approximately the same shape is formed facing the intermediate gear chamfered portion 55 on the outer peripheral portion of the upper end of the support portion 56. Therefore, even if an unexpected radial force acts on the intermediate gear 38, causing it to tilt significantly and come into contact with the intermediate gear chamfered portion 55 and the support portion chamfered portion 57, the intermediate gear chamfered portion 55 and the support portion chamfered portion 57 can slide smoothly. Therefore, it is possible to suppress further tilting of the intermediate gear 38 while suppressing rotational friction of the intermediate gear 38.

This concludes the description of the embodiment, but the present invention is not limited to the above embodiment.

For example, in the above embodiment, the intermediate shaft 36 is provided with a spherical protrusion 51, but at least the upper part of the protrusion 51 may be spherical, i.e., the protrusion 51 may be hemispherical.

In addition, in the above embodiment, the second intermediate gear 42 is arranged above the first intermediate gear 41 in the intermediate gear 38, but the present invention may also be applied to a reduction mechanism in which the first intermediate gear 41 is arranged above the second intermediate gear 42.

In addition, the present invention may be applied not only to a transmission mechanism in which the intermediate shaft 36 is arranged to extend vertically as in the above embodiment, but also to a transmission mechanism in which the intermediate shaft 36 is arranged to extend horizontally, for example.

In addition, the electric throttle valve 10 in the above embodiment is an electric throttle valve that controls the intake volume of an internal combustion engine, but it may be another type of fluid control valve, and the present invention may be applied to a reduction mechanism used for purposes other than a fluid control valve.

10 Electric throttle valve (fluid control valve)
12 Electric motor 13 Motor shaft (input shaft)
16 Valve body 17 Valve (valve body)
20 Reduction mechanism (transmission)
21 Upper body 35 Valve shaft (output shaft)
36 Intermediate shaft
37 Motor gear (input gear)
38 Intermediate gear 39 Valve gear (output gear)
41 First intermediate gear 42 Second intermediate gear 52 Recess 51 Protrusion 56 Support portion (support member)

Claims (5)

A transmission mechanism that transmits a rotational driving force from an input shaft to an output shaft that are arranged in parallel to each other on a support member,
an intermediate shaft fixed to the support member and arranged parallel to the input shaft and the output shaft;
an input gear fixed to the input shaft;
an output gear fixed to the output shaft;
an intermediate gear rotatably supported on the intermediate shaft;
the intermediate gear includes a first intermediate gear meshing with the input gear and a second intermediate gear meshing with the output gear, the first intermediate gear and the second intermediate gear being located at different positions from each other in an axial direction of the intermediate shaft,
The intermediate gear is formed with a semi-spherical recess centered on the axis of the intermediate shaft,
a convex portion formed at least semi-spherically about an axis of the intermediate shaft and inserted into the concave portion, the convex portion being disposed on the intermediate shaft; The recess is provided inside the intermediate gear,
2. The transmission mechanism according to claim 1, wherein the intermediate gear is supported by the intermediate shaft with the recessed portion placed on the protruding portion. The gear shift mechanism according to claim 2, characterized in that the curvature of the recess is smaller than the curvature of the protrusion. the input shaft is a drive shaft of a motor,
the output shaft is a valve shaft that drives a valve body,
The support member is provided on a case that supports the motor and the valve shaft,
4. A fluid control valve comprising the speed change mechanism according to claim 1, wherein the speed change mechanism is a reduction mechanism that reduces the rotation speed of the drive shaft of the motor and increases the drive torque to transmit the drive torque to the valve shaft. The fluid control valve according to claim 4, characterized in that the fluid control valve is a throttle valve that controls the intake flow rate of an internal combustion engine.

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