Throttle device

Abstract

To inhibit overload from being applied to an intermediate hook when only one of an opener spring part and a return spring part of a coil spring of a throttle device resonates.SOLUTION: A throttle device in one embodiment includes: a rotary member coupled with a throttle shaft and rotated by a driving source; and a coil spring interposed between a throttle body and the rotary member and energizing a throttle valve toward a default position. The coil spring includes a first spring part, a second spring part and an intermediate hook that connects these spring parts. The intermediate hook can engage with a first stopper provided in the rotary member and a second stopper provided in the throttle body, and is configured so that a portion on the first spring part side during engagement with the first stopper or the second stopper abuts on the first stopper or the second stopper.SELECTED DRAWING: Figure 11

Description

Technical Field

[0001] This technology relates to a throttle device.

Background Art

[0002] An automobile 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 that a certain amount of intake air can be ensured even when the 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).

[0003] 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. This coil spring is configured by connecting an opener spring portion and a return spring portion wound in opposite directions with a U-shaped intermediate hook. By locking the intermediate hook to only one of the gear and the body, one of the return spring portion and the opener spring portion is made to exert a biasing force toward the default position.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] 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 when mounted to the gear and body. Therefore, a member supporting the coil spring may be provided on the gear either inside or outside the coil spring. In the above-mentioned Japanese Patent Publication No. 2020-033942, the inner circumferential support portion supports both the opener spring portion and the return spring portion from the inside, while the outer circumferential support portion presses only the opener spring portion from the outside. When only one of the opener spring portion or the return spring portion is supported by the outer circumferential support portion in this way, the two portions become eccentric in different directions, and the contact points with the inner circumferential support portion and the outer circumferential support portion shift when viewed in the circumferential direction. As a result, the length from the intermediate hook to the support point differs between the opener spring portion and the return spring portion, and if only one resonates, an excessive load may be placed on the intermediate hook (especially the U-shaped folding point). [Means for solving the problem]

[0006] 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, and a rotating member coupled to the throttle shaft and rotated by a drive source. The throttle device further comprises a coil spring interposed between the throttle body and the rotating member for biasing the throttle valve toward its 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, and the second end is locked to a second spring locking portion provided on the throttle body. The intermediate hook is configured to engage with a first stopper provided on the rotating member and a second stopper provided on the throttle body. The intermediate hook comprises 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 the second spring portion, and an outer circumferential support portion provided on the rotating member to support the outer circumference of the first spring portion. The intermediate hook has a first portion on the side of the first spring portion and a second portion on the side of the second spring portion, and when the intermediate hook engages with the first stopper or the second stopper, the first portion abuts against the first stopper or the second stopper.

[0007] In some embodiments, when the intermediate hook engages with the first stopper or the second stopper, the second portion is configured not to come into contact with the first stopper or the second stopper.

[0008] In some embodiments, the intermediate hook has a stopper-facing surface that faces the first stopper and the second stopper, and the stopper-facing surface is inclined with respect to the central axis of the coil spring.

[0009] In some embodiments, at least one of the contact surfaces of the first stopper and the second stopper is inclined with respect to the central axis of the rotating member.

[0010] In some embodiments, the rotating member has a retaining hole that surrounds the first end of the first spring portion which is locked to the first spring locking portion.

[0011] In some embodiments, the first spring locking portion is formed as the inner wall of the retaining hole. [Brief explanation of the drawing]

[0012] [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 by a plane passing through the motor and throttle shaft, with the shaded surface indicating the cross-section. [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 is a side view showing a coil spring alone, with an intermediate hook inclined relative to the central axis. [Figure 6] 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 7] This diagram shows the throttle device housing with the cover open, when the throttle valve is in its default position. [Figure 8] This diagram shows the housing of the throttle device with the cover open when the throttle valve is in the fully closed position. [Figure 9] This diagram shows the housing of the throttle device with the cover open when the throttle valve is in the fully open position. [Figure 10] This is a view in the axial direction of the eccentric opener spring portion and the outer peripheral support portion acting on it. [Figure 11] It is a side view showing a state in which the opener spring part is eccentric in a direction different from that of the return spring part by being pressed by the outer peripheral support part. [Figure 12] It is a view of the eccentric opener spring part in the axial direction when there is no outer peripheral support part. [Figure 13] It is a side view of the eccentric opener spring part when there is no outer peripheral support part. [Figure 14] As another embodiment, it is a side view showing a gear-side stopper inclined with respect to the central axis of the throttle gear. [Figure 15] It is a perspective view showing a coil spring that tries to fit inside the outer peripheral support part during the process of being attached to the throttle gear. [Figure 16] It is a perspective view showing a coil spring attached to the throttle gear.

Mode for Carrying Out the Invention

[0013] Hereinafter, various embodiments will be described with reference to the drawings.

[0014] [Throttle Device] Figs. 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 to an 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. Further, the throttle device 10 includes a rotatable disc-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. 8) that is substantially orthogonal to the intake passage 13 and a fully open position (Fig. 9) 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.

[0015] [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 an 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.

[0016] [Coil spring] As shown in Figures 2, 3, and 5, the throttle device 10 includes a coil spring 30 that biases the throttle valve 15 toward a predetermined default position (Figure 7), which is slightly open from the fully closed position (Figure 8). 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 8) and the fully open position (Figure 9) 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.

[0017] 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 (see Figure 7) 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.

[0018] As shown in Figures 3, 5, 6, and 16, 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 7), 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 the direction of diameter reduction from their natural state and are in a state where a preload is applied (a state in which elastic energy is stored).

[0019] When the motor 22 drives the throttle gear 20 towards the fully closed position (Figure 8) 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.

[0020] When the motor 22 drives the throttle gear 20 from the default position (Figure 7) towards the fully open position (Figure 9), 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 remains 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.

[0021] 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.

[0022] [Inner Circumference Support Section] As shown in Figures 4 and 6, 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 protruding from a 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).

[0023] As schematically shown in Figures 10 and 11, the opener spring portion 37 is installed with a preload applied by twisting it in the diameter-reducing direction. As a result, the circumference 37a on the end 32 side of the opener spring portion 37 tends to eccentrically move in approximately the same direction (arrow 70) as the reaction force received from the gear-side spring locking portion 42 with respect to the central axis of the throttle gear 20. The inner circumference support portion 47 supports the inner circumference of the circumference 37a that is trying to eccentricize. Similarly, the return spring portion 35 is also installed with a preload applied by twisting it in the diameter-reducing direction. As a result, the circumference 35b on the most intermediate hook 33 side of the return spring portion 35 tends to eccentrically move in approximately the same direction (arrow 74) as the reaction force received from the gear-side stopper 44 (or body-side stopper 46) with respect to the central axis of the throttle gear 20. The inner circumference support portion 47 supports the inner circumference of the circumference 35b that is trying to eccentricize. 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.

[0024] In another embodiment (not shown), the inner circumferential support portion may be formed on the throttle shaft 17 instead of the throttle gear 20.

[0025] 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 additional inner circumference support for the return spring portion 35. However, in the following description, when simply referring to the inner circumference support, it refers to the inner circumference support 47 formed on the throttle gear 20.

[0026] [Outer perimeter support section] As shown in Figures 4 and 6, 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.

[0027] As schematically shown in Figures 12 and 13, 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 central axis of the throttle gear 20 in approximately the same direction (arrow 72) as the reaction force received from the body-side stopper 46 (or gear-side stopper 44) 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 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.

[0028] In contrast, as shown in Figures 10 and 11, 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.

[0029] 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 of the opener spring portion 37 on the intermediate hook 33 side 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 10). This reduces the friction between the opener spring portion 37 and the inner peripheral support portion 47 when the throttle gear 20 rotates.

[0030] As shown in Figure 6, 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.

[0031] The distance from the central 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.

[0032] As shown in Figure 11, 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.

[0033] [Contact angle of the intermediate hook] As shown in Figure 11, the orientation of the stopper-facing surface 34 of the intermediate hook 33 of the coil spring 30 is such that the opener spring-side leg 38 of the intermediate hook 33 (the part on the opener spring portion 37 side of the folding point 39) contacts the gear-side stopper 44. Here, the stopper-facing surface 34 of the intermediate hook 33 refers to the plane formed by the opener spring-side leg 38 and the return spring-side leg 36 of the intermediate hook 33 on the side facing the gear-side stopper 44. When viewed as a single coil spring 30 (see Figure 5), the above orientation can be achieved by tilting the stopper-facing surface 34 of the intermediate hook 33 by an angle θ with respect to the central axis 76 of the coil spring 30. The return spring-side leg 36 does not need to contact the gear-side stopper 44, but in another embodiment not shown, it may contact the gear-side stopper 44. For example, the stopper-facing surface 34 of the intermediate hook 33 can be oriented such that the angle α with respect to the contact surface 49 of the gear-side stopper 44 is between 0 and 7 degrees.

[0034] As mentioned above, the opener spring section 37 is supported from the outer circumference by the outer circumference support section 50, so its circumference 37b on the intermediate hook 33 side is separated from the inner circumference support section 47. On the other hand, the return spring section 35 is not supported by the outer circumference support section 50, so its circumference 35b on the intermediate hook 33 side is supported by the inner circumference support section 47. As a result, the opener spring section 37 is supported by the outer circumference support section 50 at a position about 3 / 4 of the way around the circumference from the intermediate hook 33, while the return spring section 35 is supported by the inner circumference support section 47 at a position about 1 / 4 of the way around, so the initial support points of the two are offset. Due to this difference in length (span) from the intermediate hook 33 to the initial support point, only one of the opener spring section 37 or the return spring section 35 tends to resonate in the axial direction of the coil spring 30. However, as described above, since the opener spring-side leg portion 38 of the intermediate hook 33 is in contact with the gear-side stopper 44, even if the opener spring portion 37 resonates, the vibration is prevented from being transmitted to the folding point 39 of the intermediate hook 33. Therefore, repeated bending and torsional stresses are suppressed at the folding point 39, and the durability of the throttle device 10 against vibration is improved.

[0035] As shown in Figure 14, in another embodiment, instead of tilting the stopper-facing surface 34 of the intermediate hook 33, the contact surface 49 of the gear-side stopper 44 can be tilted (by an angle β) with respect to the central axis of the throttle gear 20 or the stopper-facing surface 34 of the intermediate hook 33, so that the opener spring-side leg 38 of the intermediate hook 33 contacts the gear-side stopper 44. In yet another embodiment (not shown), not only can the gear-side stopper 44 be tilted, but the contact surface of the body-side stopper 46, which the intermediate hook 33 also contacts, can also be tilted in the same way. In yet another embodiment, the stopper-facing surface 34 of the intermediate hook 33 and the contact surfaces of the gear-side stopper 44 and the body-side stopper 46 can all be tilted. In these embodiments as well, if the opener spring portion 37 resonates, the vibration is prevented from being transmitted to the folding point 39 of the intermediate hook 33 for the same reasons as described above.

[0036] [Locking grooves and retaining holes] As shown in Figures 15 and 16, the gear-side spring locking portion 42, which locks the gear-side end 32 of the coil spring 30, can be provided with a locking groove 43 into which the end 32 can be fitted. Furthermore, the gear-side spring locking portion 42 can also be provided as the inner wall of a retaining hole 64 that surrounds the gear-side end 32 of the coil spring 30. This prevents the gear-side end 32 of the coil spring 30 from completely detaching from the gear-side spring locking portion 42 due to vibration during use or during assembly. For example, the retaining hole 64 can be formed by placing a bridging portion 67 between a support column 66 that forms the gear-side spring locking portion 42 and a support column 68 that forms the gear-side stopper 44. The gear-side end 32 of the coil spring 30 is particularly prevented from detaching from the gear-side spring locking portion 42 by the bridging portion 67. In an embodiment not shown, instead of the bridging portion 67, a projection may be provided that extends from the support column 66 forming the gear-side spring locking portion 42 toward the support column 68 forming the gear-side stopper 44. Even if the projection does not reach the support column 68 of the gear-side stopper 44, it is still possible to form a retaining hole that partially surrounds the gear-side end 32 of the coil spring 30.

[0037] [Installing the coil spring into the throttle gear] As shown in Figure 15, 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. Figure 16 shows the coil spring 30 correctly attached to the throttle gear 20.

[0038] [Fault Structure] As shown in Figures 4, 15, and 16, the throttle gear 20 may also be 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 of the throttle gear 20 and the gear-side spring locking portion 42. 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. The obstruction structure 60 may also be provided with an inner slope 62 that inclines inward (towards the inner peripheral support portion 47) from the top toward the base 48 of the throttle gear 20.

[0039] [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.

[0040] 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.

[0041] 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 6. Even in this embodiment, by providing the outer peripheral support portion described above, the eccentricity of the return spring portion (not the opener spring portion) can be suppressed. Furthermore, by bringing the return spring side leg of the intermediate hook into contact with the gear side stopper, even if the return spring portion resonates, the vibration can be prevented from being transmitted to the folding point of the intermediate hook.

[0042] 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]

[0043] 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 34 Intermediate hook stopper opposing surface 35 Return spring section 35b The circumference of the return spring section closest to the middle hook. 36 Intermediate hook return spring side leg 37 Opener spring section 38 Intermediate hook opener spring side leg 39 Turning point of the intermediate hook 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 43 Locking groove 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 64 Retaining hole 66 Support column for gear-side spring locking section 67 Bridge part 68 Support column for gear-side stopper 76. The central axis of the coil spring

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, and a coil spring is installed between them to bias 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, and the second end is locked to a second spring locking portion provided on the throttle body. The intermediate hook is configured to engage with a first stopper provided on the rotating member and a 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 second 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 intermediate hook has a first portion on the side of the first spring portion and a second portion on the side of the second spring portion. The intermediate hook has a stopper-facing surface that faces the first stopper and the second stopper, and the stopper-facing surface is oriented such that when the intermediate hook engages with the first stopper or the second stopper, the first portion abuts against the first stopper or the second stopper, and the second portion does not abut against the first stopper or the second stopper.

2. 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, and a coil spring is installed between them to bias 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, and the second end is locked to a second spring locking portion provided on the throttle body. The intermediate hook is configured to engage with a first stopper provided on the rotating member and a 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 second 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 intermediate hook has a first portion on the side of the first spring portion and a second portion on the side of the second spring portion, and when the intermediate hook engages with the first stopper or the second stopper, the first portion comes into contact with the first stopper or the second stopper. The throttle device wherein the intermediate hook has a stopper-facing surface that faces the first stopper and the second stopper, and the stopper-facing surface is inclined with respect to the central axis of the coil spring.

3. 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, and a coil spring is installed between them to bias 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, and the second end is locked to a second spring locking portion provided on the throttle body. The intermediate hook is configured to engage with a first stopper provided on the rotating member and a 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 second 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 intermediate hook has a first portion on the side of the first spring portion and a second portion on the side of the second spring portion, and when the intermediate hook engages with the first stopper or the second stopper, the first portion comes into contact with the first stopper or the second stopper. A throttle device in which at least one of the contact surfaces of the first stopper and the second stopper is inclined with respect to the central axis of the rotating member.

4. A throttle device according to any one of claims 1 to 3, wherein the rotating member has a retaining hole that surrounds the first end of the first spring portion which is locked to the first spring locking portion.

5. A throttle device according to claim 4, wherein the first spring locking portion is formed as the inner wall of the retaining hole.

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