Throttle device

Abstract

To prevent an outer periphery support portion for supporting the outer periphery of a coil spring from becoming unable to exert the effect due to the coil spring being attached to a wrong position on a rotating member.SOLUTION: A throttle device according to an embodiment comprises a rotating member that is coupled to a throttle shaft and rotated by a drive source, and a coil spring that is interposed between a throttle body and the rotating member and biases a throttle valve toward a default position. The coil spring has a first spring portion, a second spring portion, and an intermediate hook that connects the first and second spring portions. The rotating member has an inner periphery support portion that supports an inner peripheral side of the first spring portion, an outer periphery support portion that supports an outer peripheral side of the first spring portion, and a blocking structure for preventing the first spring portion from being fitted on an outside of the outer periphery support portion when assembling the coil spring.SELECTED DRAWING: Figure 13

Description

Technical Field

[0001] This technology relates to a throttle device.

Background Art

[0002] An automotive throttle device that adjusts the intake air volume supplied to an engine usually opens and closes an intake passage formed in a body by rotating a shaft fixed to a throttle valve (disk) with an electric motor. In many cases, such a throttle device is provided with a mechanism that moves the throttle valve to a specified default position so as to ensure a certain amount of intake air volume even when power supply to the motor is cut off. For example, in the throttle device disclosed in Japanese Patent Application Laid-Open No. 2020-033942, a throttle valve is biased toward the default position by a coil spring (torsion spring). Specifically, this coil spring is attached between the final gear of a gear train for transmitting the rotation of the electric motor to the shaft and the body of the throttle device.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] As described above, the coil spring that biases the throttle valve toward the default position may experience significant eccentricity in a portion of its circumference depending on the mounting configuration. Therefore, support members are sometimes provided on the inside or outside of the coil spring to suppress this eccentricity. In the above-mentioned publication, an outer peripheral support portion is provided on the gear to suppress the circumference that is about to become eccentric from the outside of the coil spring. However, the presence of such an outer peripheral support portion makes it possible to mistakenly install the coil spring outside the outer peripheral support portion when assembling it to the gear, so it is desirable to prevent this. [Means for solving the problem]

[0005] One aspect of this technology is a throttle device comprising: a throttle body forming an intake passage; a throttle valve for opening and closing the intake passage; a throttle shaft coupled to the throttle valve; a rotating member coupled to the throttle shaft and rotated by a drive source; and a coil spring interposed between the throttle body and the rotating member for biasing the throttle valve toward a default position. The coil spring has a first spring portion including a first end, a second spring portion including a second end, and an intermediate hook connecting the first spring portion and the second spring portion, wherein the first end is locked to a first spring locking portion provided on the rotating member, the second end is locked to a second spring locking portion provided on the throttle body, and the intermediate hook is locked to at least one of a first stopper provided on the rotating member and a second stopper provided on the throttle body. The throttle device further includes an inner circumferential support portion provided on the rotating member or the throttle shaft to support the inner circumference of the first spring portion, and an outer circumferential support portion provided on the rotating member to support the outer circumference of the first spring portion. The rotating member has a barrier structure that prevents the first spring portion from becoming trapped outside the outer circumferential support portion when the coil spring is assembled. This prevents the coil spring from being installed in the wrong position on the rotating member, which would render the outer circumferential support portion ineffective.

[0006] In some embodiments, the obstruction structure is located between the outer peripheral support portion of the rotating member and the first spring locking portion. This prevents the first spring portion from being fitted to the outer peripheral support portion in the wrong position while the first end of the coil spring is locked to the first spring locking portion of the rotating member.

[0007] In some embodiments, the obstruction structure is configured to prevent the first rotation of the first spring portion on the first end side from completely extending outside the outer peripheral support portion when attempting to engage the intermediate hook with the first stopper while the first end of the coil spring is engaged with the first spring locking portion of the rotating member. This prevents the first spring portion from being installed in the wrong position, even if a part of the first spring portion is significantly eccentric due to the force applied to the intermediate hook when attaching the coil spring to the rotating member.

[0008] In some embodiments, the obstruction structure is configured such that the first end of the coil spring is engaged with the first spring locking portion of the rotating member, and the first rotation of the first spring portion on the first end side contacts the inner surface of the obstruction structure, preventing the first rotation of the first spring portion on the first end side from becoming stuck outside the outer peripheral support portion. This prevents the first spring portion from being installed in the wrong position, even if a part of the first spring portion is significantly eccentric due to the force applied to the intermediate hook when attaching the coil spring to the rotating member.

[0009] In some embodiments, the obstruction structure protrudes axially from the base of the rotating member and has an inner slope that inclines inward from its top toward the base of the rotating member. When attempting to fit the first spring portion outside the outer peripheral support portion, the inner slope of this obstruction structure prevents the first spring portion from fitting in that position. Furthermore, since the inner slope inclines outward toward the top of the obstruction structure, it is possible to suppress the sliding of at least the circumference of the intermediate hook side of the first spring portion against the obstruction structure.

[0010] In some embodiments, the first spring portion is an opener spring portion that acts when the throttle valve is closed more than the default position, and the second spring portion is a return spring portion that acts when the throttle valve is open more than the default position. This prevents the opener spring portion from being installed in the wrong position. In particular, when the number of turns of the opener spring portion is less than the number of turns of the return spring portion, the reaction force from the spring locking portion is not easily distributed to each turn of the opener spring portion, and the eccentricity of each turn tends to be large during installation and use. Furthermore, the side that is closed more than the default position tends to be used more frequently and has more operation cycles, so the importance of the outer peripheral support portion and obstruction structure described above is considered to increase. [Brief explanation of the drawing]

[0011] [Figure 1] This is a perspective view of a throttle device as one embodiment. [Figure 2] This is a cross-sectional view of the throttle device, cut through a plane passing through the motor and throttle shaft. [Figure 3] This is an exploded view of the throttle device. [Figure 4] This is a perspective view showing the throttle gear alone. [Figure 5] This diagram shows the throttle gear with the opener spring portion of the coil spring attached, and the coil spring is cut at the intermediate hook. [Figure 6] This diagram shows the throttle device housing with the cover open, when the throttle valve is in its default position. [Figure 7] This diagram shows the housing of the throttle device with the cover open when the throttle valve is in the fully closed position. [Figure 8] This diagram shows the housing of the throttle device with the cover open when the throttle valve is in the fully open position. [Figure 9] This is a view in the axial direction of the eccentric opener spring portion and the outer peripheral support portion acting on it. [Figure 10] It is a side view of an eccentric opener spring portion and a side surface of an outer peripheral support portion acting thereon. [Figure 11] It is a view of an eccentric opener spring portion without an outer peripheral support portion as seen in the axial direction. [Figure 12] It is a side view of an eccentric opener spring portion without an outer peripheral support portion. [Figure 13] It is a perspective view showing a coil spring that attempts to correctly fit inside the outer peripheral support portion during the process of attaching it to a throttle gear. [Figure 14] It is a perspective view showing a coil spring that attempts to incorrectly fit outside the outer peripheral support portion during the process of attaching the coil spring to a throttle gear without an obstacle structure. [Figure 15] It is a view of a largely eccentric coil spring during the process of attaching it to a throttle gear and an obstacle structure that prevents its eccentricity as seen in the axial direction. [Figure 16] It is a side view showing an opener spring portion that cannot be fitted due to being blocked by an inner slope of an obstacle structure and an outer slope of an outer peripheral support portion. [Figure 17] It is a cross-sectional view showing a coil spring fitted inside an obstacle structure.

Embodiments for Carrying out the Invention

[0012] Hereinafter, various embodiments will be described while referring to the drawings.

[0013] [Throttle Device] Figures 1 to 3 show a throttle device 10 as one embodiment that is mounted on a vehicle such as an automobile and adjusts the amount of air intake into the engine. The throttle device 10 includes a throttle body 12 that forms an intake passage 13. The throttle body 12 can be made of metal or resin with a metal core. Further, the throttle device 10 includes a rotatable disk-shaped throttle valve (disk) 15 that adjusts the flow rate passing through the intake passage 13. The throttle valve 15 is fixed to a throttle shaft 17 that is rotatably supported via bearings 18 and 19 attached to the throttle body 12 on both sides of the intake passage 13. The throttle valve 15 is rotatable between a fully closed position (Fig. 7) that is substantially orthogonal to the intake passage 13 and a fully open position (Fig. 8) that is substantially parallel to the intake passage 13. When the throttle shaft 17 rotates, the throttle valve 15 opens and closes. Both the throttle valve 15 and the throttle shaft 17 can be made of metal.

[0014] [Motor and Transmission Mechanism] The throttle device 10 includes a motor 22 as a drive source 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 formed in the throttle body 12, and the throttle body 12 includes a lid 29 that closes this housing portion. As one embodiment, the transmission mechanism includes a drive gear 24 fixed to the output shaft 23 of the motor 22, an intermediate gear 26 rotatably supported by the throttle body 12 via an intermediate shaft 27, and a throttle gear 20 that is a driven gear coaxially fixed to the throttle shaft 17. The intermediate gear 26 has a large-diameter tooth portion 26a and a small-diameter tooth portion 26b coaxially fixed to the intermediate shaft 27. The drive gear 24 meshes with the large-diameter tooth portion 26a, and the tooth portion 28 of the throttle gear 20 meshes with the small-diameter tooth portion 26b. The throttle gear 20 can be made of resin. The throttle shaft 17 is inserted into a mounting hole 21 provided in the throttle gear 20 and fixed by caulking at the end. 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 rotation amount of the motor 22.

[0015] [Coil spring] As shown in Figures 2 and 3, the throttle device 10 includes a coil spring 30 that biases the throttle valve 15 toward a predetermined default position (Figure 6), which is slightly open from the fully closed position (Figure 7). This coil spring 30 functions as a torsion spring. When the motor 22 is energized (i.e., when the output shaft 23 can be controlled), the throttle valve 15 can be rotated to any position between the fully closed position (Figure 7) and the fully open position (Figure 8) against the biasing force of the coil spring 30. When the power to the motor 22 is cut off, the biasing force of the coil spring 30 automatically rotates the throttle valve 15 to the default position, allowing a small amount of air to be supplied to the engine through the intake passage 13.

[0016] Specifically, the coil spring 30 is constructed by connecting a return spring section 35 (for example, about 6 turns) and an opener spring section 37 (for example, about 2 turns), which are wound in opposite directions, and is interposed between the throttle body 12 and the throttle gear 20. Both ends 31 and 32 of the coil spring 30 are bent to protrude radially outward, with one end 31 being locked to a body-side spring locking section 40 provided on the throttle body 12, and the other end 32 being locked to a gear-side spring locking section 42 provided on the throttle gear 20. The end 31 locked to the throttle body 12 is also the end of the return spring section 35, and the end 32 locked to the throttle gear 20 is also the end of the opener spring section 37.

[0017] As shown in Figures 3 and 5, the connection between the return spring portion 35 and the opener spring portion 37 is a U-shaped folded portion, which is bent so as to protrude radially outward. This bent folded portion is configured as an intermediate hook 33 and is engaged with at least one of the gear-side stopper 44 provided on the throttle gear 20 and the body-side stopper 46 provided on the throttle body 12. When the throttle gear 20 is in the default position (Figure 6), the intermediate hook 33 is engaged with both the gear-side stopper 44 on the throttle gear 20 and the body-side stopper 46 on the throttle body 12. At this time, both the return spring portion 35 and the opener spring portion 37 are twisted in a direction that reduces their diameter from their natural state, and are in a state where a preload is applied (a state in which elastic energy is stored).

[0018] When the motor 22 drives the throttle gear 20 towards the fully closed position (Figure 7) from the default position, the intermediate hook 33 of the coil spring 30 engages with the body-side stopper 46 provided on the throttle body 12, thereby disabling the return spring portion 35, which is constrained at both ends by the throttle body 12. On the other hand, as the throttle gear 20 rotates relative to the throttle body 12 with the intermediate hook 33 engaged with the body-side stopper 46, the gear-side stopper 44 of the throttle gear 20 separates from the intermediate hook 33. As the throttle gear 20 rotates while holding the end 32 of the coil spring 30, the opener spring portion 37 twists further in the direction of reducing its diameter. When the power to the motor 22 is cut off when the throttle gear 20 is in the fully closed position rather than the default position, the throttle gear 20 is returned to the default position by the biasing force of the opener spring portion 37.

[0019] When the motor 22 drives the throttle gear 20 from the default position (Figure 6) towards the fully open position (Figure 8), the intermediate hook 33 remains locked to the gear-side stopper 44 of the throttle gear 20, thus disabling the opener spring portion 37, which is constrained at both ends by the throttle gear 20. On the other hand, as the throttle gear 20 rotates relative to the throttle body 12 while the intermediate hook 33 is locked at the gear-side stopper 44, the return spring portion 35 twists further in the direction of reducing its diameter. When the power to the motor 22 is cut off while the throttle gear 20 is in the fully open position rather than the default position, the throttle gear 20 is returned to the default position by the biasing force of the return spring portion 35.

[0020] When the throttle gear 20 rotates between the default position and the fully closed position, the opener spring portion 37 twists, but the amount of rotation of each part of the coil wire of the opener spring portion 37 at this time is not uniform. For example, the part of the opener spring portion 37 closest to the end 32 held by the throttle gear 20 rotates in accordance with the throttle gear 20, so the amount of rotation relative to the throttle gear 20 is small. On the other hand, the part of the opener spring portion 37 closest to the intermediate hook 33 constrained by the body-side stopper 46 rotates less relative to the throttle body 12, so the amount of rotation relative to the throttle gear 20 is large.

[0021] [Inner Circumference Support Section] As shown in Figures 4 and 5, the throttle gear 20 has an inner circumferential support portion 47 that protrudes toward the interior of the coil spring 30 and suppresses eccentricity of the coil spring 30. As an example, the inner circumferential support portion 47 is formed as a cylindrical portion that protrudes from the plate-shaped base on which the teeth portion 28 of the throttle gear 20 is formed. The aforementioned mounting hole 21 for fixing the throttle shaft 17 can be formed in a metal plate joined to the inside of this cylindrical inner circumferential support portion 47 by insert molding. The inner circumferential support portion 47 can be formed to a height that at least penetrates the opener spring portion 37 and can also be formed to a height that protrudes into the interior of the return spring portion 35 (for example, from the intermediate hook 33 to about two turns of the return spring portion 35).

[0022] As schematically shown in Figures 9 and 10, the opener spring portion 37 is installed with a preload applied by twisting it in the diameter reduction direction. As a result, the circumference 37a on the end 32 side of the opener spring portion 37 tends to be eccentric with respect to the axis of the throttle gear 20 in approximately the same direction (arrow 70) as the reaction force received from the gear-side spring locking portion 42. The inner circumference support portion 47 particularly supports the inner circumference side of the circumference 37a on the end 32 side of the opener spring portion 37. The inner circumference support portion 47 also suppresses eccentricity of the coil spring 30 that may occur due to twisting caused by the rotation of the throttle gear 20 during the operation of the throttle device 10.

[0023] In another embodiment (not shown), the inner circumferential support portion may be formed on the throttle shaft 17 instead of the throttle gear 20.

[0024] As shown in Figure 2, the throttle body 12 has a bearing retainer 45 that holds the bearing 18 closer to the throttle gear 20. This bearing retainer 45 is formed to a height that protrudes into the return spring portion 35 and can function as an inner circumference support portion for the return spring portion 35. However, below, when simply referring to the inner circumference support portion, it refers to the inner circumference support portion 47 for the opener spring portion 37.

[0025] [Outer perimeter support section] As shown in Figures 4 and 5, the throttle gear 20 is provided with at least one outer peripheral support portion 50 that abuts against the outer peripheral side of the opener spring portion 37 of the coil spring 30. The outer peripheral support portion 50 can be integrally formed with the throttle gear 20. In one embodiment, the outer peripheral support portion 50 is formed to extend from the base portion 48 on which the teeth portion 28 of the throttle gear 20 is formed to the same side as the inner peripheral support portion 47. For example, the outer peripheral support portion 50 can be shaped to make point contact with the opener spring portion 37, and can be cylindrical, for example, extending parallel to the axial direction of the throttle gear 20.

[0026] As schematically shown in Figures 11 and 12, when a throttle gear 120 without an outer peripheral support portion 50 is used, the circumference 37b of the opener spring portion 37 on the intermediate hook 33 side is significantly eccentric with respect to the axis of the throttle gear 20 in approximately the same direction (arrow 72) as the reaction force received from the body-side stopper 46, due to the preload applied to the opener spring portion 37. In particular, because the number of turns of the opener spring portion 37 (about 2 turns) is relatively small, the reaction force received from the body-side stopper 46 and the gear-side spring locking portion 42 is not easily distributed to each circumference, and the amount of eccentricity of each circumference of the opener spring portion 37 tends to be large. As a result, the part of the opener spring portion 37 closest to the intermediate hook 33 (right side in the figure) is pressed against the inner peripheral support portion 47, while the part on the opposite side (left side in the figure) is far away from the inner peripheral support portion 47. As the throttle gear 20 rotates from the default position toward the fully closed position, the opener spring portion 37 twists further in the direction of diameter reduction, increasing the force with which the opener spring portion 37 presses against the inner circumference support portion 47. When the throttle gear 20 rotates between the default position and the fully closed position, the intermediate hook 33 is constrained by the body-side stopper 46, so as mentioned above, the portion of the opener spring portion 37 closest to the intermediate hook 33 has a large relative rotation amount with respect to the throttle gear 20. Therefore, when this portion of the opener spring portion 37 is pressed against the inner circumference support portion 47, friction occurs between the opener spring portion 37 and the inner circumference support portion 47 when the throttle gear 20 rotates, resulting in rotational resistance of the throttle gear 20.

[0027] In contrast, as shown in Figures 9 and 10, in the above embodiment in which the throttle gear 20 is provided with an outer peripheral support portion 50, the outer peripheral support portion 50 abuts against the outer peripheral side of the circumference 37b on the intermediate hook 33 side of the opener spring portion 37, suppressing its eccentricity. As a result, the circumference 37b on the intermediate hook 33 side is separated from the inner peripheral support portion 47 of the throttle gear 20. Consequently, the inner peripheral side of the circumference 37b on the intermediate hook 33 side of the opener spring portion 37 is separated from the inner peripheral support portion 47. Therefore, friction between the opener spring portion 37 and the inner peripheral support portion 47 when the throttle gear 20 rotates between the default position and the fully closed position can be eliminated. This not only reduces wear on the inner peripheral support portion 47, but also reduces the load on the motor 22, making it possible to miniaturize the motor 22 and reduce the reduction ratio of the transmission mechanism, leading to a miniaturization of the throttle device 10.

[0028] In another embodiment (not shown), the outer peripheral support portion 50 can be configured to reduce the force with which the opener spring portion 37 pushes the inner peripheral support portion 47, instead of completely separating the circumference 37b on the intermediate hook 33 side of the opener spring portion 37 from the inner peripheral support portion 47. That is, it can be configured to push back the opener spring portion 37 in the opposite direction to the direction in which the opener spring portion 37 tends to eccentricize (arrow 72 in Figure 9). This reduces the friction between the opener spring portion 37 and the inner peripheral support portion 47 when the throttle gear 20 rotates.

[0029] As shown in Figure 5, the outer peripheral support portion 50 can be positioned to contact the circumference 37b of the opener spring portion 37 on the intermediate hook 33 side at a position within approximately 180° to 360° (for example, about 270°) from the intermediate hook 33. This avoids contact at locations where the relative rotation between the opener spring portion 37 and the inner peripheral support portion 47 is relatively large, thereby effectively reducing friction.

[0030] The distance from the axis of the throttle gear 20 to the outer surface of the inner circumference support portion 47 does not have to be constant. For example, the distance can be set to be large in the part of the outer surface of the inner circumference support portion 47 that should support the circumference 37a on the end 32 side of the opener spring portion 37, and small in the part where the circumference 37b on the intermediate hook 33 side of the opener spring portion 37 approaches the outer surface due to eccentricity.

[0031] As shown in Figure 10, the minimum distance d between the inner circumferential support portion 47 and the outer circumferential support portion 50 where the opener spring portion 37 is located can be less than twice the diameter of the coil wire of the opener spring portion 37. This prevents the coil wires of the opener spring portion 37 from overlapping between the inner circumferential support portion 47 and the outer circumferential support portion 50, thereby stabilizing the posture of the opener spring portion 37.

[0032] [Installing the coil spring into the throttle gear] As shown in Figure 13, to attach the coil spring 30 to the throttle gear 20, first the end 32 is locked to the gear-side spring locking portion 42, and then the opener spring portion 37 is twisted in the diameter-reducing direction while the intermediate hook 33 is locked to the gear-side stopper 44. At this time, care must be taken to ensure that the opener spring portion 37 is securely fitted between the inner circumference support portion 47 and the outer circumference support portion 50.

[0033] [Fault Structure] As shown in Figures 4 and 13, the throttle gear 20 is provided with an obstruction structure 60 to prevent the coil spring 30 from being installed in the wrong position. The obstruction structure 60 can be a block extending from the base 48 of the throttle gear 20 to the same side as the outer peripheral support portion 50. Preferably, the obstruction structure 60 is positioned between the outer peripheral support portion 50 and the gear-side spring locking portion 42 of the throttle gear 20. As one specific example, the obstruction structure 60 can be an arc-shaped block extending over an angular range of approximately 45° from the axis of the throttle gear 20.

[0034] As shown in Figure 14, when using a throttle gear 220 without the obstruction structure 60, the opener spring portion 37 is prone to overriding the outer peripheral support portion 50 and getting stuck on the outside during the process of installing the coil spring 30. As mentioned above, since the number of turns of the opener spring portion 37 (approximately 2 turns) is relatively small, the eccentricity of each turn of the opener spring portion 37 is large even during assembly, making it easy to overridden the outer peripheral support portion 50. If the opener spring portion 37 is installed in such an incorrect position, the effect of the outer peripheral support portion 50, which acts to separate the turn 37b on the intermediate hook 33 side of the opener spring portion 37 from the inner peripheral support portion 47, cannot be achieved.

[0035] On the other hand, as shown in Figures 15 and 16, when the obstruction structure 60 is present, if the end 32 of the opener spring portion 37 is locked to the gear-side spring locking portion 42 of the throttle gear 20 and an attempt is made to lock the intermediate hook 33 to the gear-side locking portion, even if the opener spring portion 37 is greatly eccentric due to the force applied to the intermediate hook 33 (arrow 74), at least the circumference 37a on the end 32 side of the opener spring portion 37 is prevented from going completely outside the outer peripheral support portion 50. Also, under the condition that the end 32 of the coil spring 30 is locked to the gear-side spring locking portion 42 of the throttle gear 20, the circumference 37a on the end 32 side of the opener spring portion 37 will not get stuck in a position that passes outside the outer peripheral support portion 50 while hitting the obstruction structure 60. This prevents the opener spring portion 37 from being installed in the wrong position, even if the circumference 37b on the intermediate hook 33 side of the opener spring portion 37 becomes significantly eccentric and extends to the outside of the outer peripheral support portion 50.

[0036] As shown in Figure 4, the obstruction structure 60 can also be provided with an inner slope 62 that slopes inward (towards the inner circumference support portion 47) from the top toward the base 48 of the throttle gear 20. As shown in Figures 15 and 16, even if an attempt is made to fit the opener spring portion 37 outside the outer circumference support portion 50, the inner slope 62 of the obstruction structure 60 prevents the opener spring portion 37 from fitting in that position. Furthermore, as shown in Figure 17, since the inner slope 62 slopes outward toward the top of the obstruction structure 60, it is possible to suppress the sliding of the circumference 37b of the opener spring portion 37 on the intermediate hook 33 side against the obstruction structure 60 when the throttle gear 20 rotates. Furthermore, when the coil spring 30 is assembled to the throttle gear 20, the outer peripheral support portion 50 abuts against the outer peripheral side of the circumference 37b on the intermediate hook 33 side of the opener spring portion 37, thereby suppressing its eccentricity, whereas the obstruction structure 60 does not abut against the opener spring portion 37.

[0037] As shown in Figures 4 and 16, the outer peripheral support portion 50 can be provided with an outer slope 52 that slopes inward from the base 48 of the throttle gear 20 toward the top of the outer peripheral support portion 50. As a result, even if an attempt is made to fit the opener spring portion 37 onto the outside of the outer peripheral support portion 50, the outer slope 52 of the outer peripheral support portion 50 and the inner slope 62 of the obstruction structure 60 prevent the opener spring portion 37 from fitting into that position. At the same time, a further twisting force on the opener spring portion 37 makes it easier for the opener spring portion 37 to slide inward over the outer slope 52 of the outer peripheral support portion 50 and return to the correct position.

[0038] [Other embodiments] In another embodiment not shown, depending on the rotational direction required for opening and closing the throttle valve 15 and the direction of the throttle shaft 17 extending from the throttle valve 15, the coil spring 30 may be a coil spring in a form that is a mirror image of the one shown. It goes without saying that even when such a mirror image form is used, the return spring portion and the coil spring are still wound in opposite directions to each other.

[0039] In yet another embodiment, the number of turns in the return spring portion 35 and the opener spring portion 37 of the coil spring 30 can be different from those shown. Also in yet another embodiment, the relative sizes of the diameters of the circumferences of the return spring portion 35 and the opener spring portion 37 can be set to different sizes from those shown.

[0040] In yet another embodiment, the first spring portion of the coil spring 30, which is locked to the throttle gear 20, can function as a return spring portion, and the second spring portion, which is locked to the throttle body 12, can function as an opener spring portion. In this case, the direction of rotation of the throttle gear 20 when opening and closing the throttle valve 15 will be the opposite of the direction shown in Figure 5. Even in this embodiment, the eccentricity of the return spring portion can be suppressed by providing the outer peripheral support portion as described above, and the return spring portion can be prevented from being attached to the throttle gear 20 in the wrong position by providing the obstruction structure as described above.

[0041] Although specific embodiments have been described above, this technology is not limited to these embodiments, and those skilled in the art can make various substitutions, improvements, and modifications without departing from the purpose of this technology. [Explanation of Symbols]

[0042] 10 Throttle device 12 Throttle Body 13 Intake passage 14 Housing Section 15 Throttle valve 17 Throttle shaft 18, 19 Bearings 20 Throttle Gear 21 mounting holes 22 motors 23 Output shaft 24 drive gears 26 Intermediate gear 26a Large-diameter teeth of the intermediate gear 26b Small diameter teeth of the intermediate gear 27 Intermediate axis 28. Teeth of the throttle gear 29 Cover of the housing 30 Coil Springs 31 The end of the coil spring on the body side 32 The gear-side end of the coil spring 33. Intermediate hook of coil spring 35 Return spring section 37 Opener spring section 37a Circumference of the end of the opener spring section 37b Circumference of the intermediate hook side of the opener spring section 40 Body-side spring locking part 42 Gear-side spring locking part 44 Gear-side stopper 45 Bearing retaining section 46 Body-side stopper 47 Inner Circumference Support Section 48 Base of the throttle gear 50 Outer periphery support section 52 Outer slope 60. Fault Structure 62 Inner slope

Claims

1. A throttle device, A throttle body that forms an intake passage, A throttle valve that opens and closes the aforementioned intake passage, A throttle shaft coupled to the throttle valve, A rotating member connected to the throttle shaft and rotated by a drive source, The throttle body and the rotating member are interposed to provide a coil spring that biases the throttle valve toward the default position, The coil spring has a first spring portion including a first end, a second spring portion including a second end, and an intermediate hook connecting the first spring portion and the second spring portion. The first end is locked to a first spring locking portion provided on the rotating member, the second end is locked to a second spring locking portion provided on the throttle body, and the intermediate hook is locked to at least one of the first stopper provided on the rotating member and the second stopper provided on the throttle body. The rotating member or the throttle shaft is provided with an inner circumferential support portion that supports the inner circumference of the first spring portion, and the rotating member is provided with an outer circumferential support portion that supports the outer circumference of the first spring portion. The rotating member has an obstruction structure that prevents the first spring portion from fitting outside the outer peripheral support portion when assembling the coil spring. The aforementioned obstruction structure is located between the outer peripheral support portion and the first spring locking portion of the rotating member, and protrudes axially from the base portion of the rotating member, in a throttle device.

2. A throttle device according to claim 1, wherein the obstruction structure has an inner slope that inclines inward from the top toward the base of the rotating member.

3. A throttle device according to claim 1, wherein the first spring portion is an opener spring portion that acts when the throttle valve is closed more than the default position, and the second spring portion is a return spring portion that acts when the throttle valve is open more than the default position.

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