Intake throttle valve

Abstract

To obtain a shaft thrust movement restriction structure with a small number of parts and low cost for an intake throttle valve. [Solution] One embodiment is an intake throttle valve (10) comprising a throttle body (12), a throttle valve (15), a throttle shaft (17), a needle bearing (32) that rotatably supports the throttle shaft, a throttle gear (20) that is rotated by an electric actuator, and a mounting member (50) fixed to the throttle gear. The outer ring (33) of the needle bearing is fixed to the throttle body. The throttle shaft and the mounting member have opposing regulating surfaces (17c, 52a) that sandwich the needle bearing (32), and there is a gap between at least one of the regulating surfaces and the needle bearing. The axial movement of the throttle shaft is restricted when the needle bearing contacts either of the regulating surfaces.

Description

【Technical Field】 【0001】 The technology disclosed in the present application relates to an intake throttle valve. 【Background Art】 【0002】 Vehicles such as automobiles, motorcycles, motorized bicycles, and ships equipped with an engine usually have an intake throttle valve (throttle) for controlling the intake air amount to the engine. The intake throttle valve generally opens and closes the intake passage formed in the body by rotating a shaft fixed to a throttle valve (disk) with an electric motor. The rotation of the electric motor is transmitted to the shaft via a gear train, and a final gear called a throttle gear is fixed to the shaft. The shaft is rotatably supported by bearings. 【Prior Art Documents】 【Patent Documents】 【0003】 【Patent Document 1】 Japanese Patent Application Laid-Open No. 2008-150971 【Summary of the Invention】 【Problems to be Solved by the Invention】 【0004】 The intake throttle valve disclosed in Japanese Patent Application Laid-Open No. 2008-150971 discloses a method of securely fixing a lever for controlling the opening and closing of the throttle valve to the shaft while rotatably supporting the shaft by bearings. However, this intake throttle valve is not electrified and does not have a throttle gear. Even if a throttle gear is attached to the lever of this publication, the structure for restricting the thrust movement of the shaft is complicated because it is formed using a collar or a cup member. Therefore, a structure that enables restricting the thrust movement of the shaft with a small number of parts and at a low cost is desired. 【Means for Solving the Problems】 【0005】 One aspect of this technology is an intake throttle valve comprising a throttle body forming a fluid passage, a throttle valve disposed in the fluid passage for opening and closing the fluid passage, a throttle shaft fixed to the throttle valve, a needle bearing rotatably supporting the throttle shaft, a throttle gear rotated by an electric actuator, and a mounting member fixed to the throttle gear, wherein the outer ring of the needle bearing is fixed to the throttle body, the throttle shaft and the mounting member have regulating surfaces facing each other with the needle bearing in between, and there is a gap between the regulating surface of the throttle shaft and the needle bearing, or between the regulating surface of the mounting member and the needle bearing, and the axial movement of the throttle shaft is restricted when the needle bearing contacts either the regulating surface of the throttle shaft or the regulating surface of the mounting member. This allows for restriction of the thrust movement of the shaft with a low-cost structure with a small number of parts. This restriction can suppress problems such as wear between the throttle body and throttle valve and valve lock. [Brief explanation of the drawing] 【0006】 [Figure 1] This is a cross-sectional view of an intake throttle valve as one embodiment. [Figure 2] This is a magnified view of the portion of the intake throttle valve enclosed by the dashed line in Figure 1. [Modes for carrying out the invention] 【0007】 Various embodiments of this technology will be described below with reference to the drawings. 【0008】 [Intake throttle valve] Figure 1 shows an intake throttle valve 10 as one embodiment, which is installed in vehicles such as automobiles and motorcycles to regulate the amount of air intake to the engine. The intake throttle valve 10 includes a throttle body 12 that forms a fluid passage 13 through which it passes. The fluid passage 13 constitutes part of the intake passage leading to the engine. The throttle body 12 can be made of metal or resin. The intake throttle valve 10 also includes a rotatable disc-shaped throttle valve (disc) 15 that regulates the flow rate through the fluid passage 13. The throttle valve 15 is fixed to a throttle shaft 17 which is rotatably supported by the throttle body 12. The throttle valve 15 is inserted through a slit in the throttle shaft 17 and fixed to the throttle shaft 17 with screws or the like. The throttle shaft 17 is positioned to cross the fluid passage 13 in the diametrical direction and is supported on both sides of the fluid passage 13 via bearings 32 and 19 attached to the throttle body 12. The throttle valve 15 is rotatable from a fully closed position, which is almost perpendicular to the fluid passage 13, to a fully open position, which is almost parallel to the fluid passage 13. The throttle valve 15 opens and closes as the throttle shaft 17 rotates. The throttle shaft 17 can be made of metal. 【0009】 [Motors and transmission mechanisms] The intake throttle valve 10 is equipped with a motor 22 as an electric actuator for driving the throttle valve 15. The rotation output by the motor 22 is transmitted to the throttle shaft 17 via a transmission mechanism. The motor 22 and the transmission mechanism are housed in a housing portion 12a formed in the throttle body 12, and the throttle body 12 is equipped with a lid 12b that closes this housing portion. In one embodiment, the transmission mechanism consists of a drive gear 24 fixed to the output shaft of the motor 22, an intermediate gear 26 rotatably supported in the throttle body 12 via an intermediate shaft, and a throttle gear 20, which is a driven gear, fixed coaxially to the throttle shaft 17. The intermediate gear 26 has a large-diameter tooth portion 26a and a small-diameter tooth portion 26b fixed coaxially to the intermediate shaft, with the drive gear 24 meshing with the large-diameter tooth portion 26a and the teeth portion 28 of the throttle gear 20 meshing with the small-diameter tooth portion 26b. The throttle gear 20 can be made of resin. The throttle shaft 17 is fixed to the throttle gear 20 via a mounting member 50, also called a lever, which will be described later. The motor 22 is controlled by an external electronic control unit (ECU). The opening degree of the throttle valve 15 is adjusted by controlling the rotation direction and amount of rotation of the motor 22. 【0010】 [Coil spring] The intake throttle valve 10 includes a coil spring 30 that functions as a torsion spring, biasing the throttle valve 15 toward its default position. One end of the coil spring 30 is attached to the throttle body 12, and the other end is attached to the throttle gear 20, thereby biasing the throttle valve 15 via the throttle gear 20. When the motor 22 is energized (i.e., when the output shaft can be controlled), the throttle valve 15 can be rotated to any position between the fully closed and fully open positions against the biasing force of the coil spring 30. When power to the motor 22 is cut off, the biasing force of the coil spring 30 automatically rotates the throttle valve 15 to its default position, allowing a small amount of air to be supplied to the engine through the fluid passage 13. 【0011】 [Needle bearings] As shown in Figure 2, the bearing 32 on the throttle gear 20 side is a needle bearing. The needle bearing 32 has an outer ring 33 and a plurality of needle rollers 35 that roll inside the outer ring 33. The throttle body 12 has a bearing retaining portion 45. The bearing retaining portion 45 has an inner cylindrical wall surface 45a, which holds the outer ring 33 of the bearing 32 in an interference fit. The bearing 32 can be positioned axially at the bottom surface 45b of the bearing retaining portion 45. The bearing retaining portion 45 can be configured, for example, as a cylindrical body protruding from the throttle body 12 toward the throttle gear 20 (Figure 1). One end of the coil spring 30 is positioned outside the cylindrical body constituting the bearing retaining portion 45. In another embodiment not shown, a needle bearing can be used which further has an inner ring and in which the needle rollers roll between the outer ring and the inner ring. 【0012】 [Mounting components] The throttle shaft 17 is generally fixed to the throttle gear 20 via an annular mounting member 50. The throttle gear 20 has a through-hole 20a or recess that receives the tip 17a of the throttle shaft 17. The mounting member 50 can be made of metal and can be coupled to the throttle gear 20 by insert molding into the inner wall surface 20b of the through-hole 20a of the partially resin throttle gear 20. The throttle gear 20 is coupled to the throttle shaft 17 by welding the tip 17a of the throttle shaft 17 to the mounting member 50 (for example, by laser welding). Figure 2 shows an example of a welded portion 17b. 【0013】 [Regulations] The throttle shaft 17 and the mounting member 50 have opposing restricting surfaces 17c and 52a with the needle bearing 32 in between. The distance between the restricting surface 17c of the throttle shaft 17 and the restricting surface 52a of the mounting member 50 is set such that they do not simultaneously contact the needle bearing 32. In other words, a gap exists between the restricting surface 17c of the throttle shaft 17 and the needle bearing 32, or between the restricting surface 52a of the mounting member 50 and the needle bearing 32. However, the axial movement (thrust movement) of the throttle shaft 17 is restricted by the needle bearing 32 contacting either the restricting surface 17c or 52a of the throttle shaft 17 or the mounting member 50. Therefore, the thrust movement of the throttle shaft 17 can be restricted without requiring special additional parts such as a C-ring placed around the throttle shaft 17, thereby reducing costs. 【0014】 In one embodiment, the restricting surface 17c of the throttle shaft 17 can be a stepped surface facing the needle bearing 32 provided on the throttle shaft 17. 【0015】 The mounting member 50 has, for example, a base 51 coupled to the throttle gear 20 and a cylindrical portion 52 extending from the base 51 toward the needle bearing 32. The base 51 can be flat, and its outer circumference 51a is embedded in the throttle gear 20. In one embodiment, the tip 17a of the throttle shaft 17 can be welded to the inner circumferential edge 51b of the surface 51c of the base 51 of the mounting member 50 that is farther away from the needle bearing 32. The welding may be continuous along the entire circumference of the inner circumferential edge 51b or discontinuous (e.g., point-like) at multiple locations along the inner circumferential edge 51b. In one embodiment, the restricting surface 52a of the mounting member 50 can be the tip surface of the cylindrical portion 52 facing the needle bearing 32. 【0016】 As one embodiment, the mounting member 50 can have an L-shaped cross section. That is, the inner peripheral edge 51b of the base portion 51 is circular, and the cylindrical portion 52 extends from the inner peripheral edge 51b of the base portion 51 toward the needle bearing 32. Thereby, the mounting member 50 has a simple throttle shape, and molding becomes easy. As another embodiment not shown, the mounting member 50 can have a T-shaped cross section. That is, the cylindrical portion 52 extends from a portion inside the inner peripheral edge 51b of the base portion 51 toward the needle bearing 32. As yet another embodiment not shown, the cylindrical portion 52 of the mounting member 50 can have a trapezoidal cross section. That is, the diameter can be made thicker from the tip surface (the regulating surface 52a) toward the base portion 51. 【0017】 [Assembly] At the time of assembly, first, the throttle shaft 17 is inserted into the insertion hole of the throttle body 12, and while the needle bearing 32 is inserted into the tip 17a of the throttle shaft 17, the outer ring 33 is press-fitted into the bearing holding portion 45. The throttle gear 20 in which the mounting member 50 is embedded is inserted into the tip 17a of the throttle shaft 17, and the tip 17a is welded to the mounting member 50. Next, the throttle valve 15 is inserted into the slit of the throttle shaft 17 and screwed. 【0018】 Although the specific embodiments have been described above, the present technology is not limited to these embodiments, and those skilled in the art can make various substitutions, improvements, and changes without departing from the object of the present technology. 【Explanation of Reference Numerals】 【0019】 10 Intake throttle valve 12 Throttle body 12a Housing portion 12b Cover 13 Fluid passage 15 Throttle valve 17 Throttle shaft 17a Tip 17c Regulating surface 17b Weld 17d screw hole 20 Throttle Gear 20a Penetration 20b Inner wall surface 22 motors 24 drive gears 26 Intermediate gear 26a Large diameter tooth section 26b Small diameter tooth section 28 Teeth 30 Coil Springs 32 (Needle) Bearing 33 Outer ring 35 Needle Roller 45 Bearing retaining section 45a Wall surface 45b Base 50 Mounting components 51 Base 51a Outer periphery 51b Inner periphery 51c surface 52 Cylinder part 52a Regulatory surface

Claims

[Claim 1] It is an intake throttle valve, A throttle body that forms a fluid passage, A throttle valve is disposed in the fluid passage and opens and closes the fluid passage, A throttle shaft fixed to the throttle valve, A needle bearing that rotatably supports the throttle shaft, A throttle gear that is rotated by an electric actuator, It comprises a mounting member fixed to the throttle gear, The outer ring of the needle bearing is fixed to the throttle body. The throttle shaft and the mounting member have regulating surfaces facing each other with the needle bearing in between, and there is a gap between the regulating surface of the throttle shaft and the needle bearing, or between the regulating surface of the mounting member and the needle bearing, An intake throttle valve in which the axial movement of the throttle shaft is restricted by the needle bearing contacting either the restricting surface of the throttle shaft or the restricting surface of the mounting member.

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