Method for manufacturing a throttle gear for a throttle device.
By machining the spring engagement portion of the throttle gear before assembly, the method addresses reproducibility issues in throttle gear manufacturing, ensuring accurate positioning and stable spring mounting for improved throttle valve control.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- AISAN IND CO LTD
- Filing Date
- 2024-12-04
- Publication Date
- 2026-06-16
AI Technical Summary
Existing methods for manufacturing throttle gears in throttle devices suffer from reduced reproducibility due to variations in the position and orientation of the spring's intermediate hook, complicating the adjustment of the fully closed position and default position when assembled to the throttle body.
The method involves forming the throttle gear by resin molding and subsequently machining the spring engagement portion to adjust the relationship between the fully closed and default positions before assembly, ensuring accurate alignment without spring-related variations, and enhancing the straightness of the contact surface for stable mounting.
This approach improves the reproducibility of the default position and stabilizes the mounting posture of the spring, allowing precise adjustment of the throttle valve's positions and confirming machining quality through surface properties.
Smart Images
Figure 2026097124000001_ABST
Abstract
Description
Background Art
[0001] The technology disclosed in the present application relates to a method for manufacturing a throttle gear of a throttle device.
[0002] An automobile throttle device that adjusts the intake air amount 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 for rotating 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 Unexamined Patent Application Publication No. 2022-149183, a throttle valve is urged toward the default position by a torsion spring attached to a throttle gear. In order to define this default position, the spring is provided with an intermediate hook that can engage with engaging portions provided on each of the throttle body and the throttle gear.
Prior Art Documents
Patent Documents
[0003]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0004] The above-mentioned literature discloses a method for correctly adjusting the relationship between the fully closed position and the default position by using a jig that can support the throttle gear and spring subassembly in essentially the same state as when assembled to the throttle body, and then secondarily machining the contact surface of a predetermined stopper while the subassembly is set in this jig. However, in this method, since the stopper is secondarily machined with the throttle gear and spring assembled, variations in the position of the spring's intermediate hook and the spring's orientation sometimes reduced the reproducibility when assembled to the throttle body after machining. To avoid this, it is necessary to either set the jig while taking into account the state when assembled to the throttle body, or machine the predetermined dimensions based on a virtual position that takes into account the state when assembled to the throttle body, which is complicated. Therefore, a method is desired that can accurately adjust the relationship between the fully closed position and the default position without being affected by variations in the spring. [Means for solving the problem]
[0005] One aspect of this disclosure is a method for manufacturing a throttle gear for a throttle device, wherein the throttle device includes a spring that biases the throttle gear toward a default position, and the throttle gear includes a spring engagement portion that the spring contacts when the throttle valve is opened beyond the default position, and the method comprises the steps of forming the throttle gear by resin molding and subsequently forming the contact surface of the spring engagement portion by machining the molded surface of the spring engagement portion. This allows the relationship between the fully closed position and the default position to be adjusted before assembling the throttle gear to the spring and throttle body, so that the relationship between the fully closed position and the default position can be adjusted accurately without being affected by variations in the spring. In addition, the straightness of the contact surface is increased compared to the molded surface before processing, which stabilizes the mounting posture of the spring and improves the reproducibility of the default position of the throttle valve.
[0006] In some embodiments, the throttle gear has a gear-side fully closed stopper that contacts a body-side fully closed stopper (115) provided on the throttle body of the throttle device when the throttle valve is in the fully closed position, and the contact surface of the spring engagement portion formed by machining is made with reference to the contact surface of the gear-side fully closed stopper. This makes it possible to accurately achieve an appropriate relationship between the fully closed position and the default position of the throttle valve.
[0007] In some embodiments, the throttle gear is made of a glass fiber-containing resin, and the cross-section of the glass fiber formed by the machining process is exposed on the contact surface of the spring engagement portion. This makes it possible to confirm whether or not machining has been performed by examining the surface properties of the machined portion of the throttle gear. [Brief explanation of the drawing]
[0008] [Figure 1] This is a perspective view of a throttle device according to one embodiment. [Figure 2] This is a longitudinal cross-sectional view of the throttle device in Figure 1, taken along the line II-II in Figure 1, viewed from the axial direction of the air passage. [Figure 3] This is a longitudinal cross-sectional view of the throttle device in Figure 1, taken from a direction perpendicular to the axis of the air passage, along the line III-III in Figure 1. [Figure 4] Figure 1 is a side view of the throttle device. [Figure 5] Figure 1 is an exploded perspective view of the throttle gear and spring that make up the throttle device. [Figure 6] This is a perspective view showing the throttle gear and spring, as well as the throttle body stopper, with the throttle valve in its default position. [Figure 7] This is a plan view showing the throttle gear and spring, and the throttle body stopper, with the throttle valve in its default position. [Figure 8] This is a perspective view showing the throttle gear and spring, and the throttle body stopper, with the throttle valve in the fully closed position. [Figure 9] This is a plan view showing the throttle gear, spring, and throttle body stopper when the throttle valve is in the fully closed position. [Figure 10] This is a side view of a throttle gear having a contact surface for the gear-side spring engagement portion formed by machining, with only the gear-side spring engagement portion shown in cross-section. [Modes for carrying out the invention]
[0009] Next, various embodiments will be described with reference to the drawings.
[0010] [Throttle device] Figures 1 to 4 show a throttle device as one embodiment that is mounted on a vehicle such as an automobile and adjusts the amount of air intake to the engine. The throttle device comprises a throttle body 10, and the throttle body 10 has a passage forming portion 11 that forms a substantially cylindrical air passage (bore) 11h which becomes part of the intake passage to the engine.
[0011] A rotatable, disc-shaped throttle valve 20 is positioned within the air passage 11h of the throttle body 10 to regulate the airflow through the air passage 11h. The throttle valve 20 is rotatably supported within the air passage 11h between a fully closed position and a fully open position. The throttle body 10 is provided with a throttle shaft 21 that extends across the air passage 11h. The throttle shaft 21 is fixed to the pivot point of the throttle valve 20 in a manner that prevents relative rotation. The throttle shaft 21 is rotatably supported on both sides of the air passage 11h by bearings 11r and 11j mounted on the throttle body 10.
[0012] The throttle device includes a motor 14 as a drive source for driving the throttle valve 20. The rotation output by the motor 14 is transmitted to the throttle shaft 21 via a transmission mechanism. In one embodiment, the transmission mechanism consists of a drive gear 14w fixed to the output shaft of the motor 14, an intermediate gear 16 rotatably supported on the throttle body 10 via an intermediate shaft, and a throttle gear 30, which is a driven gear coaxially fixed to the throttle shaft. The motor 14 and the transmission mechanism are housed in a gear housing portion 12 and a motor housing portion 13, respectively, which are formed integrally with the passage forming portion 11 of the throttle body 10. The gear housing portion 12 and the motor housing portion 13 are closed by a cover member (not shown). The intermediate gear 16 has large-diameter teeth 16r and small-diameter teeth 16s, with the drive gear 14w meshing with the large-diameter teeth 16r and the teeth 31 of the throttle gear 30 meshing with the small-diameter teeth 16s. The opening degree of the throttle valve 20 is adjusted by controlling the rotation direction and amount of rotation of the motor 14.
[0013] [Throttle gear] The throttle gear 30 can be made of resin. The resin can be a fiber-reinforced resin containing fibers such as glass fibers. As shown in Figure 5, the throttle gear 30 has, for example, a cylindrical portion 32 and a flange portion 33 extending outward from the end of the cylindrical portion 32. The teeth 31 of the throttle gear 30 are arranged on a part of the outer circumference of the flange portion 33.
[0014] As shown in Figure 2, the throttle gear 30 is mounted to the end of the throttle shaft 21, which protrudes into the gear housing portion 12 of the throttle body 10, in a manner that prevents relative rotation. The throttle gear 30 includes a connecting plate 35 fixed to a cylindrical portion 32 (e.g., an inner flange portion 34). The connecting plate 35 can be fixed, for example, by insert molding its outer circumference into the cylindrical portion 32 of the throttle gear 30. The connecting plate 35 has a through hole 35k. The end of the throttle shaft 21 is inserted through the through hole 35k of the connecting plate 35 and fixed by an appropriate method such as crimping, screwing, or welding. This holds the throttle shaft 21 and the throttle gear 30 in a manner that prevents relative rotation.
[0015] As shown in FIGS. 4 and 5, the throttle gear 30 has a fully closed stopper 37 that can abut against a stopper 115 provided on the throttle body 10. The fully closed position (the two-dot chain line in FIG. 3 and FIG. 8) of the throttle valve 20 is defined by the abutment between the abutting surface 37m of the fully closed stopper 37 of the throttle gear 30 and the abutting surface 115f of the stopper 115 of the throttle body 10.
[0016] [Spring] As shown in FIGS. 5 to 9, the throttle device includes a torsion spring 40 that biases the throttle valve 20 toward the default position (the solid line in FIG. 3 and FIG. 6). The default position is a predetermined position that is opened by a small angle from the fully closed position. When the motor 14 is energized, the throttle valve 20 can be rotated to any position between the fully closed position and the fully open position against the biasing force of the spring 40. When the power supply to the motor 14 is cut off, the throttle valve 20 is automatically rotated to the default position by the biasing force of the spring 40, and a small amount of air can be supplied to the engine through the air passage 11h.
[0017] The spring 40 can be configured such that a return spring portion 43 and an opener spring portion 45 wound in opposite directions are connected in series, and is interposed between the throttle body 10 and the throttle gear 30 (around the cylindrical portion 32 of the throttle gear 30) (FIG. 2). Both end portions 43f and 45b of the spring 40 are bent so as to protrude radially outward, and one end portion 43f is locked to a spring locking portion 116 (FIG. 4) provided on the throttle body 10, and the other end portion 45b is locked to a spring locking portion 31z provided on the throttle gear 30.
[0018] The connection part between the return spring part 43 and the opener spring part 45 is a U-shaped folded part, and this folded part is bent so as to protrude radially outward. This bent folded part serves as an intermediate hook 47 and engages with at least one of the contact surface 38k of the gear-side spring engaging part 38 provided on the throttle gear 30 and the contact surface 115f of the stopper (body-side spring engaging part) 115 (FIG. 4) provided on the throttle body 10. The gear-side spring engaging part 38 can be formed, for example, to protrude in the same direction as the cylindrical part 32 near the spring locking part 31z from the flange part 33 of the throttle gear 30.
[0019] When the throttle gear 30 is in the default position (FIGS. 6 and 7), the intermediate hook 47 is locked to both the gear-side spring engaging part 38 provided on the throttle gear 30 and the stopper 115 provided on the throttle body 10. At this time, both the return spring part 43 and the opener spring part 45 are in a state where they are twisted in the direction of reducing the diameter from the natural state and are preloaded (a state where elastic energy is stored).
[0020] When the throttle gear 30 tries to rotate from the default position toward the fully closed position (FIGS. 8 and 9) by the drive of the motor 14, the intermediate hook 47 of the spring 40 is locked to the stopper 115 provided on the throttle body 10, so the return spring part 43 whose both ends are restrained by the throttle body 10 is invalidated. On the other hand, since the throttle gear 30 rotates relative to the throttle body 10 while the intermediate hook 47 is locked to the body-side stopper 115, the gear-side spring engaging part 38 of the throttle gear 30 separates from the intermediate hook 4 by. Since the throttle gear 30 rotates while holding the end part 45b of the spring 40, the opener spring part 45 is further twisted in the direction of reducing the diameter. When the power supply to the motor 14 is cut off when the throttle gear 30 is on the fully closed position side rather than the default position, the throttle gear 30 is returned to the default position by the biasing force of the opener spring part 45.
[0021] [[ID=II]] When the motor 14 drives the throttle gear 30 towards the fully open position, the intermediate hook 47 remains engaged with the gear-side spring engagement portion 38 of the throttle gear 30, thus disabling the opener spring portion 45, which is constrained at both ends by the throttle gear 30. Meanwhile, as the throttle gear 30 rotates relative to the throttle body 10 while the intermediate hook 47 remains engaged with the gear-side spring engagement portion 38, the return spring portion 43 twists further in the direction of reducing its diameter. When the power to the motor 14 is cut off while the throttle gear 30 is in the fully open position rather than the default position, the throttle gear 30 is returned to the default position by the biasing force of the return spring portion 43.
[0022] Furthermore, as shown in Figures 6 to 9, the contact surface 115f of the stopper 115 of the throttle body 10 can be formed such that the portion that the intermediate hook 47 of the spring 40 contacts (body-side spring engagement portion) and the portion that the fully closed stopper 37 of the throttle gear 30 contacts (body-side fully closed stopper) are on the same plane. However, in another embodiment not shown, it is also possible to form both portions of the contact surface 115f on different planes or to provide them at completely different positions on the throttle body 10.
[0023] In another embodiment not shown, the return spring and the opener spring may be formed as separate springs rather than as part of a continuous single spring 40 (i.e., the return spring portion 43 and the opener spring portion 45) as described above. In this case, the portion corresponding to the intermediate hook 47 can be provided on a connecting member that connects the return spring portion 43 and the opener spring portion 45. Such a configuration is disclosed, for example, in Japanese Patent Application Publication No. 2018-100598.
[0024] [Formation of the contact surface of the gear-side spring engagement portion] As shown in Figure 10, the contact surface 38k of the gear-side spring engagement portion 38 provided on the throttle gear 30 is formed after the throttle gear 30 is formed by resin molding, but before it is assembled to the throttle body 10. Specifically, the contact surface 38k is formed at a predetermined angle θ corresponding to the default opening when viewed from the contact surface 37m of the fully closed stopper 37 of the throttle gear 30 by cutting the molded surface 38a of the gear-side spring engagement portion 38 using an appropriate cutting tool. This allows the relationship between the fully closed position and the default position to be adjusted before the throttle gear 30 is assembled to the spring 40 and the throttle body 10, so that the relationship between the fully closed position and the default position can be adjusted accurately without being affected by variations in the spring. In addition, the straightness of the contact surface 38k is higher compared to the molded surface 38a before processing, which stabilizes the mounting posture of the spring 40 and improves the reproducibility of the default position of the throttle valve 20. Furthermore, if the throttle gear 30 is made of a fiber-containing resin such as glass fiber, the cross-section of the glass fiber formed by machining will be exposed on the contact surface 38k. This makes it possible to confirm whether or not machining has been performed by examining the surface properties of the machined part of the throttle gear 30.
[0025] [Assembly of the spring and throttle gear] Next, the spring 40 is assembled to the throttle gear 30, and the subassembly of the throttle gear 30 and spring 40 is set in the throttle body 10. At this stage, the throttle gear 30 and the throttle shaft 21 are still able to rotate relative to each other. Then, with the fully closed stopper 37 of the throttle gear 30 in contact with the contact surface 115f of the stopper 115 of the throttle body 10, the throttle valve 20, which is fixed to the throttle shaft 21, is held in the fully closed position. This determines the relative positional relationship between the throttle gear 30 and the throttle valve 20 (throttle shaft 21). Then, while maintaining this positional relationship, the throttle shaft 21 and the throttle gear 30 are fixed so that they cannot rotate relative to each other by means such as the aforementioned crimping.
[0026] Although various embodiments have been described above, this technology is not limited to those embodiments, and those skilled in the art can make various modifications, substitutions, and improvements without departing from the spirit of this technology. [Explanation of Symbols]
[0027] 10 Throttle Body 11h air passage 11 Passage forming part 12 Gear housing section 13 Motor housing section 14 motors 20 Throttle valve 21 Throttle shaft 30 Throttle Gear 31 teeth 31z Spring locking part 32 Cylindrical section 33 Flange section 35 Connecting Plates 37 Fully closed stopper 37m contact surface 38 Gear-side spring engagement portion 38a Molding surface 38k contact surface 40 (torsion) spring 43 Return spring section 43f end 45 Opener spring section 45b end 47 Intermediate hook 115 Stopper (body-side spring engagement part, body-side fully closed stopper) 115f Contact surface 116 Spring locking part
Claims
1. A method for manufacturing a throttle gear for a throttle device, The throttle device includes a spring that biases the throttle gear toward the default position, and the throttle gear includes a spring engagement portion that the spring contacts when the throttle valve is opened beyond the default position. A step of forming the throttle gear by resin molding, A method comprising the step of subsequently machining the molded surface of the spring engagement portion to form the contact surface of the spring engagement portion.
2. The method according to claim 1, The throttle gear has a gear-side fully closed stopper that contacts a body-side fully closed stopper provided on the throttle body of the throttle device when the throttle valve is in the fully closed position. The method for forming the contact surface of the spring engagement portion by the aforementioned cutting process is performed with reference to the contact surface of the gear-side fully closed stopper.
3. The method according to claim 1, The throttle gear is made of a glass fiber-containing resin, and the contact surface of the spring engagement portion has the cross-section of the glass fiber formed by the machining process exposed.