Speed ​​change mechanism and fluid control valve

Abstract

To provide a transmission mechanism for suppressing friction, and a fluid control valve.SOLUTION: The transmission mechanism includes an intermediate shaft 36 fixed to a support part 56 provided on a valve body of a motor throttle valve and arranged in parallel to a motor shaft and a valve shaft, and an intermediate gear 38 rotatably supported by the intermediate shaft 36, the intermediate gear 38 having a first intermediate gear 41 engaging with a motor gear 37 fixed to the motor shaft, and a second intermediate gear 42 engaging with a valve gear 39 fixed to the valve shaft, the first intermediate gear 41 and the second intermediate gear 42 being arranged side by side in the axial direction of the intermediate shaft 36 and constructed integrally with each other. In the intermediate gear 38, a semispherical recessed part 52 is formed recessed downward around the axial center. On the intermediate shaft 36, a protruded part 51 is formed spherically around the axial center and protruded upward. The intermediate gear 38 is supported with the recessed part 52 placed on the protruded part 51.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a speed change mechanism and a structure of a fluid control valve equipped with a speed change mechanism. [Background technology]

[0002] For example, electric throttle valves have been widely adopted in recent years for throttle valves that control the amount of intake air in internal combustion engines. Most electric throttle valves have an electric motor, a reduction mechanism, and a throttle valve built into the body.

[0003] 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 (motor output shaft) of an electric motor 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. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6419344 Summary of the Invention [Problem to be solved by the invention]

[0005] In the electric throttle valve of Patent Document 1, a first intermediate gear and a second intermediate gear are arranged in the intermediate gear so as to be offset from each other at different positions in the axial direction (the up-down direction on the paper of Figures 1 and 2 of Patent Document 1).

[0006] Therefore, when the intermediate gear is driven, the intermediate gear receives radial forces from the motor gear and from the throttle gear in opposite directions at different axial positions, causing the intermediate gear to tilt.

[0007] When the intermediate gear tilts in this manner, there is a possibility that the outer peripheral end at the axial end of the intermediate gear will 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 possibly shortening the life of the reduction mechanism and the motor.

[0008] The present invention has been made in consideration of such problems, and its object is to provide a speed change mechanism that suppresses an increase in friction due to inclination of the intermediate gear, and a fluid control valve equipped with such a speed change mechanism. [Means for solving the problem]

[0009] In order to achieve the above-mentioned object, the transmission mechanism of the present invention is a transmission mechanism that transmits a rotational driving force from an input shaft arranged parallel to each other on 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 from each other in the axial direction of the intermediate shaft, the intermediate gear is formed with a hemispherical recess centered on the axis of the intermediate shaft, and the intermediate shaft is formed with a convex portion that is formed at least hemispherically centered on the axis of the intermediate shaft and is inserted into the recess and positioned.

[0010] Preferably, the recess is provided inside the intermediate gear, and the recess is placed on the protrusion, Intermediate Gear is supported by the intermediate shaft And good.

[0011] Also, preferably, the curvature of the recessed portion is smaller than the curvature of the protruding portion.

[0012] Furthermore, 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 on a case that supports the motor and the valve shaft, and the fluid control valve further comprises a speed change mechanism that is a reduction mechanism that reduces the speed of rotation of the drive shaft of the motor, increases the drive torque, and transmits the increased drive torque to the valve shaft.

[0013] In addition, preferably, the fluid control valve is a throttle valve which controls the intake flow rate of an internal combustion engine. Effect of the Invention

[0014] According to the reduction gear mechanism of the present invention, since the intermediate gear is rotatably supported on the intermediate shaft by inserting the hemispherical convex portion into the hemispherical concave portion, 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, thereby 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 gear mechanism, a fluid control valve with excellent responsiveness and a long life can be obtained. [Brief description of the drawings]

[0015] [Figure 1] 1 is a side view of an electric throttle valve according to an embodiment of the present invention; [Diagram 2] FIG. 2 is a top view of the electric throttle valve with the cover removed. [Diagram 3] FIG. 2 is a vertical cross-sectional view of the upper part of the electric throttle valve. [Figure 4] FIG. 2 is an enlarged vertical cross-sectional view of the vicinity of an intermediate shaft of the electric throttle valve. [Diagram 5] 5 is an explanatory diagram of the direction of a force that an intermediate gear receives when the motor is driven. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

[0017] Fig. 1 is a side view of an electric throttle valve 10 (fluid control valve) according to one embodiment of the present invention. Fig. 2 is a top view of the electric throttle valve 10 with the cover 11 removed. Fig. 3 is a vertical cross-sectional view of the upper part of the electric throttle valve 10. Fig. 4 is an enlarged cross-sectional view of the vicinity of the intermediate shaft 36 of the electric throttle valve 10.

[0018] 3 is a cross-sectional view of the upper part of the electric throttle valve 10 cut vertically, more specifically, cut by a plane including the axes of a motor shaft 13 (input shaft), a valve shaft 35 (output shaft) and an intermediate shaft 36 (intermediate shaft) described below. In addition, 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 a reduction mechanism 20 described below is located above it.

[0019] An electric throttle valve 10 according to 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.

[0020] 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 path cross-sectional area, and an electric motor 12 that drives the valve 17.

[0021] 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 such that the upper body 21 and the lower body 22 are fixed together by bolts 23.

[0022] An opening 25 is provided at the top of the upper body 21 so as to face the accommodation space 19 , and the opening 25 is covered by a cover 11 .

[0023] The cover 11 is also provided with a connector 30 for connecting wiring for supplying power to the electric motor 12 and wiring for connecting to a rotation angle sensor (not shown) to the outside. The connector 30 is disposed on the upper part of the electric motor 12.

[0024] As shown in FIG. 3, in the accommodation space 19 between the upper body 21 and the cover 11, a speed reduction mechanism 20 and the electric motor 12 are accommodated.

[0025] The motor shaft 13, which is the drive shaft of the electric motor 12, and the valve shaft 35 (output shaft) which drives the valve 17 extend in the vertical direction and are arranged parallel to each other. The upper ends of the motor shaft 13 and the valve shaft 35 are arranged to face from an 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.

[0026] Between the motor shaft 13 and the valve shaft 35, an intermediate shaft 36 (intermediate shaft) is provided which is fixed to the upper body 21 and the cover 11 and extends in the vertical direction parallel to the motor shaft 13 and the valve shaft 35.

[0027] 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.

[0028] 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 aligned in the vertical direction, i.e., connected in the axial direction of the intermediate shaft 36, and are integrally configured.

[0029] The reduction gear 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.

[0030] Incidentally, a return spring (not shown) is provided inside the upper body 21. The return spring rotates the valve shaft 35 relative to the upper body 21, biasing the valve 17, for example, to a predetermined intermediate opening state. Therefore, in the electric throttle valve 10, the valve 17 is in a predetermined intermediate opening state when the operation of the electric motor 12 is stopped, and the valve 17 is opened or closed from the predetermined intermediate opening by operating the electric motor 12.

[0031] Of the intermediate gears 38, the first intermediate gear 41 is disposed close to the electric motor 12, and the second intermediate gear 42 is disposed on the cover 11 side. Therefore, the motor gear 37 is disposed at a position close to the electric motor 12 by aligning with the first intermediate gear 41 in the up-down axial direction, and the valve gear 39 is disposed at a position far from the valve 17 by aligning with the second intermediate gear 42 in the up-down axial direction.

[0032] 4, the intermediate gear 38 has a hole 40 at its axis, 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.

[0033] 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 .

[0034] Meanwhile, the intermediate gear 38 is provided inside with a recess 52 that contacts the protrusion 51. The recess 52 is formed so as to be recessed upward. That is, 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.

[0035] The curvature of the recessed portion 52 is slightly smaller than that of the protruding portion 51, i.e., the recessed portion 52 has a gentler curve than the protruding portion 51. Therefore, the intermediate gear 38 is supported such that the recessed portion 52 and the protruding portion 51 are in surface contact in a substantially circular band shape, or at least in line contact in a circular shape.

[0036] 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.

[0037] FIG. 5 is an explanatory diagram of the direction of the force that the intermediate gear 38 receives when the motor is driven.

[0038] With the above-mentioned configuration, in the reduction gear mechanism 20 of the electric throttle valve 10 of this embodiment, by driving the electric motor 12 to rotate 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 Fig. 5, radial forces (radial forces) F1, F2 received by the intermediate gear 38 act in opposite directions toward the axis center at different positions in the axial direction of the intermediate shaft 36. More specifically, 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 axial distance (vertical height on the page of FIG. 5) of the intermediate shaft 36 based on the contact surface between the recessed portion 55 of the intermediate gear 38 and the protruding portion 57 of the support portion 56, and radial forces F1, F2 act on the intermediate gear 38 in opposite directions. As a result, these radial forces F1, F2 cause the intermediate gear 38 to tilt slightly on a plane passing through the axis when it rotates.

[0039] In this embodiment, a hemispherical recess 52 formed inside the intermediate gear 38 contacts an upper portion of a spherical protrusion 51 formed on the intermediate shaft 36, and the intermediate gear 38 is rotatably supported by the intermediate shaft 36, so that 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 span of the electric motor 12 and the reduction mechanism 20 can be extended.

[0040] 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, the foreign matter or the like 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 makes it possible to prevent foreign matter or the like from accumulating between the recess 52 and the protrusion 51 and maintain the sliding performance between the recess 52 and the protrusion 51.

[0041] Furthermore, since the curvature of the recessed portion 52 is smaller than the curvature of the protruding portion 51, the dimension of the gap between the recessed portion 52 and the protruding portion 51 increases radially outward. This makes it easier to expel foreign matter, etc., that has entered between the recessed portion 52 and the protruding portion 51 radially outward.

[0042] Furthermore, intermediate gear chamfered portion 55 is formed on the outer peripheral edge of hole portion 40 at the lower end of intermediate gear 38, and support portion chamfered portion 57 of approximately the same shape is formed on the outer peripheral portion of the upper end of support portion 56 facing intermediate gear chamfered portion 55, so that even if an unexpected radial force acts on intermediate gear 38, causing it to tilt significantly and come into contact with intermediate gear chamfered portion 55 and support portion chamfered portion 57, intermediate gear chamfered portion 55 and support portion chamfered portion 57 can slide smoothly. Therefore, further tilt of intermediate gear 38 can be suppressed while suppressing rotational friction of intermediate gear 38.

[0043] Although the description of the embodiment is now completed, the aspects of the present invention are not limited to the above embodiment.

[0044] For example, in the above embodiment, the intermediate shaft 36 is provided with the spherical protrusion 51, but at least the upper part of the protrusion 51 may be spherical, that is, the protrusion 51 may be hemispherical.

[0045] 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.

[0046] Furthermore, the present invention may be applied not only to a transmission mechanism in which the intermediate shaft 36 is disposed so as to extend vertically as in the above embodiment, but also to a transmission mechanism in which the intermediate shaft 36 is disposed so as to extend horizontally, for example.

[0047] Furthermore, although the electric throttle valve 10 in the above embodiment is an electric throttle valve that controls the amount of intake air of an internal combustion engine, 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. [Explanation of symbols]

[0048] 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 1st intermediate gear 42 Second intermediate gear 52 Recess 51 Convex 56 Support part (support member)

Claims

1. 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;

2. 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.

3. 3. The transmission mechanism according to claim 2, wherein a curvature of the recessed portion is smaller than a curvature of the protruding portion.

4. 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, The speed change mechanism is a reduction mechanism that reduces the rotation speed of the drive shaft of the motor, increases the drive torque, and transmits the increased drive torque to the valve shaft. A fluid control valve comprising the speed change mechanism according to any one of claims 1 to 3.

5. 5. The fluid control valve according to claim 4, wherein the fluid control valve is a throttle valve for controlling an intake air flow rate of an internal combustion engine.

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