Speed change mechanism and fluid control valve

Abstract

A variable speed mechanism and a fluid control valve. The variable speed mechanism includes an intermediate shaft (36) fixed to a support portion (56) provided to a valve body of an electric throttle valve and arranged in parallel with a motor shaft and a valve shaft, and an intermediate gear (38) rotatably arranged to the intermediate shaft, the intermediate gear (38) having a first intermediate gear (41) engaged with a motor gear fixed to the motor shaft and a second intermediate gear (42) engaged with a valve gear fixed to the valve shaft, the first intermediate gear (41) and the second intermediate gear (42) being arranged in line along an axis direction of the intermediate shaft (36) and integrally formed, a lower end portion of the intermediate gear (38) being formed with a semispherical recessed portion (55) recessed upward with a center of an axis of the intermediate shaft (36), and an opposite surface of the support portion (56) opposite to the recessed portion (55) of the intermediate gear (38) being formed with a semispherical protruded portion (57) protruded upward with the center of the axis of the intermediate shaft (36) and supporting the recessed portion (55).

Description

Technical Field

[0001] This invention relates to a speed change mechanism and a fluid control valve including the speed change mechanism. Background Technology

[0002] In recent years, electric throttle valves have become the most common type of valve used in throttle valves, such as those used to control the intake volume of internal combustion engines. Most electric throttle valves have an electric motor, a reduction gear, and a throttle valve built into their main body.

[0003] Japanese Patent No. 6419344 (hereinafter referred to as Patent Document 1) discloses an example of an electric throttle valve. In the main body of the electric throttle valve disclosed in Patent Document 1, the throttle valve shaft that drives the valve core is arranged parallel to the drive shaft (motor output shaft) of the electric motor, and a reduction mechanism is arranged between the motor output shaft and the throttle valve shaft. The reduction mechanism consists of a motor gear, an intermediate shaft, an intermediate gear, and a throttle valve gear (valve gear). The motor gear is fixed to the motor output shaft, the intermediate shaft is fixed to the main body and arranged parallel to both the motor output shaft and the throttle valve shaft, the intermediate gear is rotatably supported on the intermediate shaft, and the throttle valve gear (valve gear) is fixed to the valve shaft. A first intermediate gear and a second intermediate gear are formed within the intermediate gear, wherein the first intermediate gear meshes with the motor gear, and the second intermediate gear meshes with the throttle valve gear.

[0004] In the electric throttle valve of Patent Document 1, the first intermediate gear and the second intermediate gear are axially aligned (Patent Document 1). Figure 1 , 2 They are staggered at different positions on the paper (vertical direction). Therefore, during driving, the intermediate gear is subjected to radial forces from the motor gear and the throttle valve gear. These two radial forces are opposite to each other at different positions in the axial direction, causing the intermediate gear to tilt.

[0005] If the intermediate gear is tilted as described above, the following technical problem may occur: the outer peripheral end of the axial end of the intermediate gear may come into contact with the supporting part of the main body, namely the intermediate shaft, thereby causing friction on the rotation of the intermediate gear, which will reduce the life of the reduction mechanism and the motor. Summary of the Invention

[0006] The present invention was developed in view of the above-mentioned technical problems, and its object is to provide a speed change mechanism and a fluid control valve including the speed change mechanism, which can reduce the friction when the intermediate gear contacts the support member due to the tilt of the intermediate gear.

[0007] To achieve the above objectives, the transmission mechanism of the present invention is a transmission mechanism that transmits rotational driving force from an input shaft arranged parallel to a support member to an output shaft, comprising: 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 disposed on the intermediate shaft, the intermediate gear having 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 relative to each other in the axial direction of the intermediate shaft, a hemispherical recess centered on the axis of the intermediate shaft being formed on either the axial end of the intermediate gear or on the opposing surface of the support member opposite to the axial end of the intermediate gear, and a protrusion centered on the axis of the intermediate shaft and inserted into and disposed in the recess being formed on the other side.

[0008] Preferably, the recess is provided at the axial end of the lower side of the intermediate gear and is formed in a recessed manner towards the upper side, and the recess is placed on the protrusion so that the intermediate shaft is supported by the support member.

[0009] Furthermore, preferably, the curvature of the concave portion is less than the curvature of the convex portion.

[0010] Furthermore, the fluid control valve of the present invention includes a speed change mechanism, wherein the input shaft is a drive shaft of a motor, the output shaft is a valve shaft that drives the valve core, the support member is disposed on a housing that supports the motor and the valve shaft, and the speed change mechanism is a speed reduction mechanism that reduces the rotation of the drive shaft of the motor, increases the driving torque and transmits it to the valve shaft.

[0011] Furthermore, preferably, the fluid control valve is a throttle valve that controls the intake flow rate of the internal combustion engine.

[0012] According to the reduction mechanism and fluid control valve of the present invention, the intermediate gear is rotatably disposed on the intermediate shaft, and a hemispherical protrusion is inserted into the hemispherical recess, thereby supporting the intermediate gear. Therefore, when the intermediate gear is rotated by the rotation of the input shaft, even if the intermediate gear is tilted relative to the intermediate shaft, the protrusion and recess will slide smoothly, thereby reducing the friction between the recess and the protrusion. Furthermore, by transmitting the driving force of the motor to the valve shaft via the aforementioned reduction mechanism, a fluid control valve with excellent responsiveness and long service life can be obtained. Attached Figure Description

[0013] Figure 1 This is a side view of an electric throttle valve according to an embodiment of the present invention. Figure 2 This is a top view of the electric throttle valve after the cover has been removed. Figure 3 This is a longitudinal sectional view of the upper part of the electric throttle valve. Figure 4 This is an enlarged longitudinal sectional view of the area near the central pivot of the electric throttle valve. Figure 5 This is a diagram illustrating the direction of the force acting on the intermediate gear when the motor is driven. Symbol Explanation 10. Electric throttle valve (fluid control valve) 12 electric motors 13 Motor shafts (input shafts) 16 valve body 17. Valve (Valve Core) 20. Reduction gear (gearbox) 21 upper body 35 Valve Shaft (Output Shaft) 36. Intermediate pivot (intermediate shaft) 37. Motor gear (input gear) 38 intermediate gears 39 Valve Gear (Output Gear) 41 First intermediate gear 42 Second intermediate gear 55 recess 56 Support section 57 convex part Detailed Implementation

[0014] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

[0015] Figure 1 This is a side view of an electric throttle valve 10 (fluid control valve) according to an embodiment of the present invention. Figure 2 This is a top view of the electric throttle valve 10 after the cover 11 has been removed. Figure 3 This is a longitudinal sectional view of the upper part of the electric throttle valve 10. Figure 4 This is an enlarged cross-sectional view near the intermediate pivot 36 of the electric throttle valve 10. in addition, Figure 3 This is a cross-sectional view showing the upper part of the electric throttle valve 10 cut along the longitudinal direction. Specifically, Figure 3 This is a cross-sectional view of the upper part of the electric throttle valve 10, taken through a plane containing the axes of the motor shaft 13 (input shaft), the valve shaft 35 (output shaft), and the intermediate shaft 36 (intermediate shaft). Furthermore, in the electric throttle valve 10 of this embodiment described below, the motor shaft 13 extends vertically and the reduction mechanism 20, described later, is positioned above it.

[0016] The electric throttle valve 10 of one embodiment of the present invention is, for example, a fluid control valve for controlling the intake flow rate of an internal combustion engine installed in a car.

[0017] like Figures 1-3 As shown, the electric throttle valve 10 includes a valve body 16 (shell), a valve 17 (valve core), and an electric motor 12. The valve body 16 (shell) forms an intake passage 15 (fluid passage). The valve 17 (valve core) opens and closes the intake passage 15 to adjust the flow path cross-sectional area. The electric motor 12 drives the valve 17.

[0018] The valve body 16 has an upper body 21 and a lower body 22, and is constructed such that the upper body 21 and the lower body 22 are fixed to each other by bolts 23. The upper body 21 forms a storage space 19 for a built-in electric motor 12, and the lower body 22 forms an air intake passage 15 and is provided with a valve 17.

[0019] An opening 25 is provided on the upper part of the upper body 21, the opening 25 faces the storage space 19, and the opening 25 is covered by a cover 11.

[0020] Furthermore, a connector 30 is provided on the cover 11, which is used to connect the power supply wiring to the electric motor 12 to wiring connected to a rotation angle sensor (not shown) or the like externally. The connector 30 is positioned above the electric motor 12.

[0021] like Figure 3 As shown, the storage space 19 between the upper main body 21 and the cover 11 houses the deceleration mechanism 20 and the electric motor 12.

[0022] The drive shaft 13 of the electric motor 12 and the valve shaft 35 that 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 configured to protrude from the opening 25 of the upper body 21. In other words, the opening 25 of the upper body 21 opens in the direction of extension of the upper end of the motor shaft 13.

[0023] An intermediate shaft 36 is provided between the motor shaft 13 and the valve shaft 35. The intermediate shaft 36 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.

[0024] The reduction mechanism 20 consists of a motor gear 37 (input gear), an intermediate shaft 36, an intermediate gear 38, and a valve gear 39 (output gear). The motor gear 37 (input gear) is fixed to the upper end of the motor shaft 13, the intermediate gear 38 is rotatably supported on the intermediate shaft 36, and the valve gear 39 (output gear) is fixed to the upper end of the valve shaft 35.

[0025] 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. The first intermediate gear 41 and the second intermediate gear 42 are arranged in the vertical direction, that is, they are connected in the axial direction of the intermediate shaft 36 and are integrally formed.

[0026] The reduction mechanism 20 transmits the rotational driving force generated by 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 speed, thereby driving the valve 17 to rotate and thus opening and closing the valve 17.

[0027] Additionally, a return spring (not shown) is provided within the upper body 21. The return spring rotates the valve shaft 35 relative to the upper body 21, thereby applying force to the valve 17 in a manner that allows it to be in a predetermined intermediate opening state, for example. Therefore, in the electric throttle valve 10, when the electric motor 12 stops working, the valve 17 is in a predetermined intermediate opening state. By operating the electric motor 12, the valve 17 is opened and closed from the predetermined intermediate opening state.

[0028] The first intermediate gear 41 of the intermediate gear 38 is configured close to the electric motor 12, and the second intermediate gear 42 is configured on the cover 11 side. Therefore, the motor gear 37 is configured close to the electric motor 12 with its axial vertical position aligned with the first intermediate gear 41, and the valve gear 39 is configured away from the valve 17 with its axial vertical position aligned with the second intermediate gear 42.

[0029] like Figure 4 As shown, a hole 40 for inserting an intermediate shaft 36 is provided at the axis of the intermediate gear 38. Furthermore, a recess 55 is formed at the axial end of the lower side of the intermediate gear 38, the recess 55 being approximately hemispherical and recessed upwards with the axis of the intermediate shaft 36 as the center. The recess 55 is formed such that the lower end of the hole 40 faces downwards and extends radially outwards.

[0030] On the other hand, a cylindrical support portion 56 (support member) protruding upward is provided on the upper body 21. The lower end of the intermediate rotating shaft 36 is inserted into and fixed to the upper end of the support portion 56. Furthermore, a protrusion 57 is provided on the upper end of the support portion 56, which protrudes upward in an approximately hemispherical shape with the axis of the intermediate rotating shaft 36 as the center. The protrusion 57 slopes smoothly downward and radially outward from the outer periphery of the intermediate rotating shaft 36. In addition, the intermediate gear 38 is arranged with a recess 55 resting on the upper side of the protrusion 57 of the support portion 56.

[0031] Furthermore, the curvature of the recess 55 is slightly less than that of the opposing convex portion 57; that is, the recess 55 is formed as a gentler curve compared to the convex portion 57. Therefore, the intermediate gear 38 is supported in such a manner that the recess 55 and the convex portion 57 make approximately circular strip-shaped ground contact, or at least circular ground line contact.

[0032] Figure 5 This is a diagram illustrating the direction of the force acting on the intermediate gear 38 when the motor is driven.

[0033] According to the above structure, in the reduction mechanism 20 of the electric throttle valve 10 of this embodiment, the motor shaft 13 is rotated by driving the electric motor 12, causing the intermediate gear 38 to be subjected to a rotational force from the motor gear 37 and a reaction force from the rotational force from the valve gear 39. At this time, as... Figure 5 As shown, the radial forces F1 and F2 acting on the intermediate gear 38 are located at different positions along the axial direction of the intermediate shaft 36 and act in opposite directions towards the axis. Specifically, taking the contact surface between the recess 55 of the intermediate gear 38 and the protrusion 57 of the support portion 56 as a reference, the distance between the meshing position of the motor gear and the intermediate gear 38 and the aforementioned contact surface along the axial direction of the intermediate shaft 36 is (…). Figure 5 The vertical height of the paper surface), and the distance between the meshing position of the valve gear 39 and the intermediate gear 38 and the aforementioned contact surface on the axial direction of the intermediate rotating shaft 36 (the vertical height of the paper surface), and the distance between the contact surfaces on the intermediate rotating shaft 36. Figure 5 Due to the different heights of the paper, radial forces F1 and F2 act on the intermediate gear 38 in opposite directions. Therefore, under the action of these radial forces F1 and F2, when the intermediate gear 38 rotates, the intermediate gear 38 is slightly tilted on the plane passing through the axis of the intermediate shaft 36.

[0034] In this embodiment, the lower surface of the opposing intermediate gear 38 and the upper surface of the support portion 56 of the upper body 21 are in circular strip-shaped ground contact through a hemispherical concave portion 55 and a convex portion 57. Therefore, even if the intermediate gear 38 tilts, the concave portion 55 and the convex portion 57 will slide smoothly, thereby reducing the friction (friction force) between the concave portion 55 and the convex portion 57 when the intermediate gear 38 rotates. Therefore, since the friction at the reduction mechanism 20 when driving the electric motor 12 to rotate is reduced, the responsiveness of the opening and closing drive of the valve 17 in the electric throttle valve 10 can be improved, and the lifespan of the electric motor 12 and the reduction mechanism 20 can be extended.

[0035] Furthermore, the lower surface of the intermediate gear 38 is formed as an upwardly recessed portion 55, and the support portion 56 is formed as an upwardly protruding portion 57, with the upper surface of the protrusion 57 inclined radially outward and downward. Therefore, even if foreign objects or the like enter between the recess 55 and the protrusion 57, they will slide radially outward from the upper surface of the protrusion 57 and be easily discharged from between the recess 55 and the protrusion 57. Thus, the accumulation of foreign objects or the like between the recess 55 and the protrusion 57 can be suppressed, and the sliding performance of the recess 55 and the protrusion 57 can be maintained.

[0036] Furthermore, the curvature of the recess 55 is smaller than that of the protrusion 57, therefore, the size of the gap between the recess 55 and the protrusion 57 increases radially outward. As a result, foreign objects or the like that entering between the recess 55 and the protrusion 57 can be more easily discharged radially outward.

[0037] The above description of the implementation methods ends here, but the present invention is not limited to the above-described implementation methods.

[0038] For example, in the above embodiment, a recess 55 is provided in the intermediate gear 38 and a protrusion 57 is provided in the support portion 56. However, a protrusion 57 protruding downwards may be provided on the lower surface of the intermediate gear 38 and a recess 55 recessed upwards may be provided in the support portion 56.

[0039] Furthermore, in the above embodiment, a second intermediate gear 42 is disposed on the upper side of the first intermediate gear 41 in the intermediate gear 38. However, the present invention can also be applied to a reduction mechanism in which the first intermediate gear 41 is disposed on the upper side of the second intermediate gear 42.

[0040] Furthermore, the present invention can be applied not only to a transmission mechanism in which the intermediate shaft 36 is configured to extend in the vertical direction as in the above-described embodiment, but also to a transmission mechanism in which the intermediate shaft 36 is configured to extend in the horizontal direction.

[0041] Furthermore, the electric throttle valve 10 in the above embodiment is an electric throttle valve that controls the intake volume of an internal combustion engine. However, it can also be other fluid control valves. In addition, the present invention can also be applied to deceleration mechanisms used for purposes other than fluid control valves.

Claims

1. A speed-changing mechanism for transmitting rotational driving force from an input shaft arranged parallel to a support member to an output shaft, the speed-changing mechanism comprising: An intermediate shaft, supported by the support member, and arranged parallel to the input shaft and the output shaft; An input gear, which is fixed to the input shaft; An output gear, the output gear being fixed to the output shaft; as well as An intermediate gear, which is rotatably mounted on the intermediate shaft. The support member is disposed in the housing that supports the motor and the output 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 being located at different positions relative to each other along the axial direction of the intermediate shaft. A hemispherical recess centered on the axis of the intermediate shaft is formed on either the axial end of the intermediate gear or the opposing surface of the support member opposite to the axial end of the intermediate gear, and a protrusion centered on the axis of the intermediate shaft and inserted into and disposed in the recess is formed on the other side.

2. The speed-changing mechanism as described in claim 1, characterized in that, The recess is located at the axial end of the lower side of the intermediate gear and is formed by recessing upwards. The recess is provided on the protrusion, such that the intermediate shaft is supported on the support member.

3. The speed-changing mechanism as described in claim 2, characterized in that, The curvature of the concave portion is less than the curvature of the convex portion.

4. A fluid control valve, comprising the speed-changing mechanism according to any one of claims 1 to 3, The input shaft is the drive shaft of the motor. The output shaft is the valve shaft that drives the valve core. The support member is disposed in the housing that supports the motor and the valve shaft. The speed change mechanism is a mechanism that reduces the rotation speed of the motor's drive shaft, increases the driving torque, and transmits it to the valve shaft.

5. The fluid control valve as described in claim 4, characterized in that, The fluid control valve is a throttle valve that controls the intake air flow of an internal combustion engine.

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