Throttle device

Abstract

This provides a throttle device that allows for the sharing of the throttle body and can accommodate two types of specifications, one with a throttle valve opening and closing direction and the other with a reversed direction. [Solution] A throttle device 1A comprises a throttle body 2, a throttle shaft 5 fixed to a driven gear 15, a throttle valve 7 that opens and closes via the throttle shaft 5 within a throttle bore 2b, a lever portion 19d provided on the driven gear 15, a fully closed stopper 23 that restricts the lever portion 19d to the fully closed position, and a fully open stopper that restricts the lever portion 19d to the fully open position. The fully closed stopper is a boss portion 25 provided to protrude from the inside and outside of the gear housing chamber 4, and has two pairs of substantially parallel surfaces, allowing a screw hole 26 for passing an adjustment screw 27 through to be formed.

Description

Technical Field

[0001] The present invention relates to a throttle device.

Background Art

[0002] For example, in this type of throttle device, a throttle valve is supported by a throttle shaft so as to be opened and closed within a throttle bore of a throttle body, and the throttle shaft is projected into a gear accommodation chamber formed in the throttle body to fix a driven gear. Then, the driving force of a motor is transmitted to the driven gear, and the throttle valve is driven in the opening direction against the biasing force of a return spring acting in the closing direction. A stopper is provided on the driven gear, and a lever portion is moved along an arc-shaped locus centered on the throttle shaft as the driven gear rotates. A fully closed stopper and a fully open stopper are provided in the gear accommodation chamber, and as the driven gear rotates, the lever portion is brought into contact with the fully closed stopper to regulate the fully closed position of the throttle valve, and the lever portion is brought into contact with the fully open stopper to regulate the fully open position of the throttle valve.

[0003] In such a throttle device, different intake air amount characteristics may be required according to the specifications of the engine to be mounted, and if throttle devices corresponding to the required intake air amount characteristics are individually manufactured, the manufacturing cost will increase. Therefore, for example, in the technique of Patent Document 1, by sharing the throttle body and attaching different throttle valves, it is possible to realize the required intake air amount characteristics without causing a cost increase.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Incidentally, in the throttle device described above, there are cases where two specifications are requested, in which the opening and closing directions of the throttle valve are reversed. Specifically, one specification has the characteristic of opening the throttle valve as the throttle shaft rotates in a predetermined direction, while the other specification has the characteristic of closing the throttle valve as the throttle shaft rotates in a predetermined direction. It should be noted that products with both of these specifications may be requested from the initial stages of development, or the other specification may be requested as an add-on while one specification is in production.

[0006] However, the throttle devices of the two specifications have different positions for the fully open stopper and fully closed stopper located within the gear housing. This necessitates the production of throttle bodies with different specifications, and consequently, the use of different molds to shape each throttle body, leading to increased manufacturing costs. While the technology described in Patent Document 1 can achieve different intake air volume characteristics with a common throttle body, it cannot handle reversing the opening and closing direction of the throttle valve, and a fundamental solution has been needed for some time.

[0007] This invention was made to solve these problems, and its objective is to provide a throttle device that can accommodate two types of specifications, in which the throttle body is shared and the opening and closing direction of the throttle valve is reversed. [Means for solving the problem]

[0008] To achieve the above objective, the present invention provides a throttle device comprising a throttle body, a throttle shaft fixed to a driven gear, a throttle valve that opens and closes via the throttle shaft within a throttle bore, a lever portion provided on the driven gear, a fully closed stopper that restricts the lever portion to the fully closed position, and a fully open stopper that restricts the lever portion to the fully open position, wherein the fully closed stopper is a boss portion provided to protrude inward and outward from the gear housing chamber, has two pairs of substantially parallel surfaces, and forms a screw hole for passing an adjustment screw. In other embodiments, the gear case of the gear housing may have two bosses integrally formed in place for fully opening stoppers. In other embodiments, one or more spring hooks may be provided in the gear housing chamber. In other embodiments, the boss portion may be roughly rhombic in cross-sectional view. In other embodiments, the boss portion may have a first flat portion and a second flat portion, respectively, which function as seating surfaces for a lock nut that restricts the rotation of the adjustment screw, with space provided around each of them. In other embodiments, an adjustment screw may be installed on the first planar portion when the driven gear rotates in one direction. In other embodiments, an adjustment screw may be installed on the second plane when the driven gear rotates in another direction. [Effects of the Invention]

[0009] According to the throttle device of the present invention, it is possible to accommodate two types of specifications by sharing the throttle body and reversing the opening and closing direction of the throttle valve. [Brief explanation of the drawing]

[0010] [Figure 1] This is a front view showing a throttle device according to the first specification of the embodiment. [Figure 2] This is a perspective view showing the throttle device of specification 1. [Figure 3] This is a cross-sectional view taken along line III-III in Figure 2. [Figure 4] This is an exploded perspective view corresponding to Figure 2. [Figure 5] This is an exploded perspective view from a different angle than Figure 4. [Figure 6] This is a side view corresponding to the view taken by arrow A in Figure 3, with the throttle valve fully closed. [Figure 7] This is a cross-sectional view taken along line VII-VII in Figure 3, with the throttle valve fully closed. [Figure 8] This is a side view corresponding to Figure 6, showing the gear housing chamber with the left throttle body alone. [Figure 9] It is a perspective view corresponding to FIG. 8 showing the gear accommodation chamber with the left throttle body alone. [Figure 10] It is a side view corresponding to FIG. 6 with the throttle valve of the throttle device of the second specification fully closed. [Figure 11] It is a cross-sectional view corresponding to FIG. 7 with the throttle valve fully closed. [Figure 12] It is an exploded perspective view corresponding to FIG. 5. [Figure 13] It is a side view corresponding to FIG. 6 showing the case where the throttle device of Alternative Example 1 is assembled as the first specification. [Figure 14] It is a side view corresponding to FIG. 10 showing the case where the throttle device of Alternative Example 1 is assembled as the second specification. [Figure 15] It is an exploded perspective view corresponding to FIG. 5 showing the passive gear of Alternative Example 2.

Mode for Carrying Out the Invention

[0011] Hereinafter, although one embodiment in which the present invention is embodied in a throttle device for a two-cylinder engine will be described, the gist of the present invention will be described prior thereto. As described above, in this type of throttle device, there may be a demand for two types of specifications in which the opening and closing direction of the throttle valve is reversed. However, in both throttle devices, since the positions of the fully open stopper and the fully closed stopper provided in the gear accommodation chamber are different from each other, it is necessary to manufacture throttle bodies of different specifications, resulting in a high manufacturing cost.

[0012] In view of such problems, the present invention is a throttle body shared between throttle devices of both specifications by providing both the fully open stopper and the fully closed stopper that function in the throttle devices of both specifications in the gear accommodation chamber of the throttle body. Hereinafter, the throttle device assembled as one specification will be referred to as the throttle device 1A of the first specification, and the throttle device assembled as the other specification will be referred to as the throttle device 1B of the second specification. First, the throttle device 1A of the first specification will be described.

[0013] [Throttle device 1A of the first specification] FIG. 1 is a front view showing the throttle device 1A of the first specification of the present embodiment, FIG. 2 is a perspective view showing the throttle device 1A of the first specification, FIG. 3 is a sectional view taken along line III-III of FIG. 2, FIG. 4 is an exploded perspective view corresponding to FIG. 2, FIG. 5 is an exploded perspective view seen from a direction different from FIG. 4, FIG. 6 is a side view corresponding to the arrow A view of FIG. 3 with the throttle valve fully closed, and FIG. 7 is a sectional view taken along line VII-VII of FIG. 3 with the throttle valve fully closed.

[0014] In each figure, the front-rear, left-right, and up-down directions are shown mainly with respect to the driver on the vehicle. In the in-vehicle state where the throttle device 1A is assembled to the engine mounted on the vehicle, the throttle device 1A is maintained in the posture shown in each figure. In the following description, assuming that the throttle device 1A is in the in-vehicle state, the front-rear, left-right, and up-down directions are expressed. This also applies to the throttle device 1B of the second specification described later.

[0015] The throttle device 1A of the first specification has a characteristic of opening the throttle valve as the throttle shaft 5 rotates clockwise in FIG. 6. The throttle device 1A is formed by connecting a left throttle body 2 shown by a solid line in FIG. 1 and a right throttle body 3 shown by a two-dot chain line to each other. In the present embodiment, each throttle body 2, 3 is manufactured as a molded product by aluminum die casting, but it is not limited thereto. For example, it may be injection molded using a synthetic resin material having heat resistance.

[0016] As shown in Figures 1, 3, and 4, a left flange portion 2a, which is an annular shape and opens to the right, is integrally formed on the right side of the left throttle body 2. Similarly, a right flange portion 3a, which is an annular shape and opens to the left, is integrally formed on the left side of the right throttle body 3. The left flange portion 2a and the right flange portion 3a are overlapped and fastened together with screws (not shown), thereby joining the left and right throttle bodies 2 and 3. The left and right flange portions 2a and 3a form a gear case 16, and a gear housing chamber 4 is defined inside it. One throttle bore 2b and 3b are provided through the left and right throttle bodies 2 and 3, respectively, in the front-to-back direction. Although not shown, when the throttle device 1A is mounted in a vehicle, the front ends of each throttle bore 2b and 3b are connected to the respective cylinders of the engine, and the rear ends are connected to the air cleaner.

[0017] A single throttle shaft 5 is installed in the left and right throttle bodies 2 and 3, respectively, passing through the throttle bores 2b and 3b and the gear housing chamber 4 from left to right. As shown in Figure 3, bearings 6 are provided on both the left and right sides of the throttle bore 2b of the left throttle body 2, and the throttle shaft 5 is supported by each bearing 6 so as to be rotatable about axis C1. Although not shown in the figure, the throttle shaft 5 is similarly supported by bearings in the right throttle body 3 so as to be rotatable. Throttle valves 7 are installed in each throttle bore 2b and 3b and are fixed to the throttle shaft 5 by screws 8, and each opens and closes in accordance with the rotation of the throttle shaft 5.

[0018] As shown in Figures 1, 4, and 5, a motor housing chamber 2c is integrally formed on the upper side of the left throttle body 2, and a motor 9 is housed inside it. The output shaft 9a of the motor 9 protrudes into the gear housing chamber 4, and a drive gear 10 is fixed to it. As the motor 9 operates, the drive gear 10 rotates around axis C2. Within the gear housing chamber 4, a first-stage intermediate gear 12 is supported by a support shaft 11 at a position below the drive gear 10 so as to be rotatable around axis C3, and a next-stage intermediate gear 14 is supported by a support shaft 13 at a position below the support shaft 11 so as to be rotatable around axis C4.

[0019] The first intermediate gear 12 is formed by integrally creating a large-diameter portion 12a and a small-diameter portion 12b. The large-diameter portion 12a meshes with the drive gear 10, and the small-diameter portion 12b meshes with the next intermediate gear 14. The next intermediate gear 14 meshes with a driven gear 15 fixed to the throttle shaft 5. In the following description, this driven gear will be referred to as the first driven gear 15, and the second specification driven gear, which will be described later, will be referred to as the second driven gear 32 to distinguish between them.

[0020] As shown in Figures 3-5, the first driven gear 15 consists of a cylindrical base 18 fitted onto the throttle shaft 5 and fixed by a pin 17, and a sector-type gear section 19 injection-molded from a synthetic resin material using a core metal 19a as an insert material. A crimping hole 19b, which penetrates the core metal 19a, is fitted onto the base 18 and crimped, thereby connecting the gear section 19 to the base 18.

[0021] As shown in Figures 3, 5, and 6, a torsion bar type return spring 20 is wound around the throttle shaft 5, and the biasing force of the return spring 20 acts in the direction of closing the throttle valve 7. In the following description, this return spring will be referred to as the first return spring 20, and the second type of return spring described later will be referred to as the second return spring 33 to distinguish between them. The configuration around this first return spring 20 will be described in detail below.

[0022] The left flange portion 2a of the left throttle body 2 consists of a bottom wall 2a1 facing to the right, a peripheral wall 2a2 surrounding the bottom wall 2a1, a cylindrical portion 2a3 that is cylindrical around the throttle shaft 5 and protrudes to the right from the bottom wall 2a1, and an annular recess 2a4 formed by a stepped recess in the bottom wall 2a1 surrounding the cylindrical portion 2a3. These portions 2a1, 2a2, 2a3, and 2a4 are integrally formed on the left throttle body 2 to form the left flange portion 2a.

[0023] Furthermore, a cylindrical portion 19c, which forms a cylindrical shape centered on the throttle shaft 5, is integrally formed on the left side of the gear portion 19 of the first driven gear 15, so as to face the right side of the cylindrical portion 2a3 with a small gap between them. The first return spring 20 is wound around these cylindrical portions 2a3 and 19c, and its right end is hooked onto a lever portion 19d that is bent and formed on the core metal 19a of the first driven gear 15.

[0024] Figure 6 shows the first driven gear 15 with the throttle valve 7 in the fully closed position, indicated by a dashed line, with the lever portion 19d located at the lowest point within the gear housing chamber 4. The first return spring 20 is wound to the left from its right end, which is hooked onto the lever portion 19d, and its left end is hooked onto a first spring hook 21 integrally formed in the annular recess 2a4 at a position slightly above and in front of the axis C1 of the throttle shaft 5. As a result, in this first specification throttle device 1A, the throttle shaft 5 is biased counterclockwise around axis C1 in Figure 6 via the first driven gear 15, and the throttle valve 7 is held in the fully closed position, as shown in Figure 7.

[0025] The driving force of the motor 9 is transmitted to the throttle shaft 5 via the drive gear 10, the first intermediate gear 12, the next intermediate gear 14, and the first driven gear 15. As the driving force increases clockwise, the throttle shaft 5, together with the first driven gear 15, rotates clockwise against the biasing force of the first return spring 20, opening the throttle valve 7. Accordingly, the lever portion 19d moves clockwise along the first trajectory L1, which is an arc-shaped path centered on the axis C1 of the throttle shaft 5, as shown by the thick arrow in Figure 6. Also, as the driving force of the motor 9 decreases, the throttle shaft 5, together with the first driven gear 15, rotates counterclockwise under the biasing force of the first return spring 20, closing the throttle valve 7. Accordingly, the lever portion 19d moves counterclockwise along the first trajectory L1.

[0026] Such clockwise rotation of the first driven gear 15 corresponds to "rotation in another direction" in the present invention, and counterclockwise rotation of the first driven gear 15 corresponds to "rotation in one direction" in the present invention. Then, the amount of intake air supplied to the engine via the throttle bores 2b and 3b is adjusted according to the opening and closing of each throttle valve 7.

[0027] The right throttle body 3 is provided with a connector 22 that is electrically connected to the motor 9. When the throttle device 1A is installed in a vehicle, the coupler of the harness extending from the engine control controller on the vehicle side is connected to the connector 22, and the connectors of the throttle sensor (not shown) provided on the throttle device are also connected to the controller via the harness. As a result, detection information such as the throttle opening output from the throttle sensor is input to the controller, and the drive signal output from the controller is supplied to the motor 9 to adjust the opening of the throttle valve 7, and consequently the amount of intake air from the engine.

[0028] On the other hand, a fully closed stopper 23 and a fully open stopper 24 (boss) are provided on the bottom wall 2a1 inside the gear housing chamber 4 to allow the throttle device to function in the first specification. In the following description, these stoppers will be referred to as the first fully closed stopper 23 and the first fully open stopper 24, and the stoppers of the second specification throttle device 1B, which will be described later, will be referred to as the second fully closed stopper 30 and the second fully open stopper 31 (boss) to distinguish them from each other.

[0029] The first and second fully closed stoppers 23 and 30 function to restrict the fully closed position of the throttle valve 7, and a small amount of intake air corresponding to the fully closed position is supplied to the engine cylinder via the throttle bore 2b and 3b. As will be described later, these fully closed stoppers 23 and 30 can be adjusted to their fully closed positions, so the idle speed can be adjusted accordingly. The first and second fully open stoppers 24 and 31 function to restrict the fully open position of the throttle valve 7. The motor 9 drives the throttle valve 7 between the fully closed and fully open positions, and the controller performs throttle valve 7 opening degree learning.

[0030] Figure 8 is a side view corresponding to Figure 6, showing the left throttle body 2 alone inside the gear housing chamber 4, and Figure 9 is a perspective view corresponding to Figure 8, showing the left throttle body 2 alone inside the gear housing chamber 4. As shown in Figures 6, 8, and 9, the first fully closed stopper 23 consists of a boss portion 25 integrally formed as a single component within the gear housing chamber 4, a first screw hole 26 formed in the boss portion 25, an adjustment screw 27 screwed into the first screw hole 26, and a lock nut 28 that restricts the rotation of the adjustment screw 27.

[0031] The boss portion 25 is integrally formed at a position slightly below and forward of the axis C1 of the throttle shaft 5 within the gear housing chamber 4, and at the corner between the bottom wall 2a1 and the peripheral wall 2a2. In the cross-sectional view shown in Figure 6, it has a roughly rhombic shape with two pairs of roughly parallel surfaces. Specifically, the boss portion 25 consists of an inner first planar portion 25c and an inner second planar portion 25d that are adjacent planar and protrude into the gear housing chamber 4, and an outer first planar portion 25a and an outer second planar portion 25b that are adjacent planar and protrude outside the gear housing chamber 4. The inner first planar portion 25c and the outer first planar portion 25a are roughly parallel to each other, and the inner second planar portion 25d and the outer second planar portion 25b are roughly parallel to each other. Space is provided around the first and second planar portions 25a and 25b, respectively, for adjusting the adjustment screw 27 using a tool. Furthermore, as shown in Figure 6, the angle α between the inner first planar portion 25c and the inner second planar portion 25d, and the angle α between the outer first planar portion 25a and the outer second planar portion 25b are approximately 82°, but are not limited to this angle.

[0032] As shown in Figure 6, the first screw hole 26 is formed to penetrate the boss portion 25 from the outer first planar portion 25a to the inner first planar portion 25c. More specifically, the first screw hole 26 penetrates the boss portion 25 along the tangent to the first trajectory L1, and the outer first planar portion 25a and the inner first planar portion 25c are perpendicular to the axis C5 of the first screw hole 26. The tip of the adjustment screw 27 screwed into the first screw hole 26 protrudes into the gear housing chamber 4 from the inner first planar portion 25c of the boss portion 25 and is oriented clockwise, while the base end protrudes to the outside of the left throttle body 2 from the outer first planar portion 25a of the boss portion 25, and a lock nut 28 is screwed onto it. The lock nut 28 restricts rotation by fastening the adjustment screw 27 to the boss portion 25 with the outer first planar portion 25a as the seating surface.

[0033] Therefore, the lever portion 19d, moving counterclockwise along the first trajectory L1, contacts the tip of the adjustment screw 27, thereby restricting the fully closed position of the throttle valve 7. To adjust this fully closed position, the adjustment screw 27 is rotated by releasing the lock nut 28 using a tool, and then the lock nut 28 is tightened. The screwed position of the adjustment screw 27 relative to the first screw hole 26 changes, and accordingly, the tip is displaced along the axis C5, changing the contact position of the lever portion 19d and, consequently, the fully closed position of the throttle valve 7. As a result, a small amount of intake air corresponding to the fully closed position is supplied into the engine cylinder via the throttle bores 2b and 3b, thereby making it possible to adjust the engine's idle speed.

[0034] In addition, as shown in Figure 6, space is provided around the first planar section 25a for adjusting the adjustment screw 27 using a tool, making adjustment work easy. Although it will not be repeated in this explanation, the same effect can be achieved when adjusting the throttle device 1B of the second specification, as space is provided around the second planar section 25b.

[0035] Furthermore, as shown in Figures 6, 8, and 9, considering that the lever portion 19d moves along the trajectory L1, the first fully open stopper 24 is provided on the first trajectory L1. More specifically, the first fully open stopper 24 is integrally formed so as to protrude to the right from the top wall 2a1 at a position slightly above and rear of the axis C1 of the throttle shaft 5 in the gear housing chamber 4. Therefore, the lever portion 19d moving clockwise along the first trajectory L1 comes into contact with the first fully open stopper 24, thereby restricting the fully open position of the throttle valve 7.

[0036] Therefore, in the throttle device 1A assembled as the first specification, the first fully closed stopper 23 allows the fully closed position of the throttle valve 7 to be arbitrarily adjusted, thereby adjusting the engine's idle speed. In addition, the first fully open stopper 24 restricts the fully open position of the throttle valve 7, and the controller can perform opening degree learning based on the fully open and fully closed positions.

[0037] On the other hand, as will be described later based on Figure 10, in the second specification throttle device 1B, the boss portion 25 is shared with the first specification, and a second screw hole 34 is formed in the boss portion 25 in a different direction. An adjustment screw 27 is screwed into this second screw hole 34 and fastened with a lock nut 28, thereby forming a second fully closed stopper 30. The fully closed position and fully open position of the throttle valve 7 are then regulated by this second fully closed stopper 30 and second fully open stopper 31.

[0038] Therefore, in order to regulate the fully closed and fully open positions of the throttle valve 7, the first specification throttle device 1A utilizes a first fully closed stopper 23 and a first fully open stopper 24 located in the gear housing chamber 4, while the second specification throttle device 1B utilizes a second fully closed stopper 30 and a second fully open stopper 31, also located in the gear housing chamber 4. In the second specification throttle device 1B, these second fully closed stopper 30 and second fully open stopper 31 cause the throttle valve 7 to open as the throttle shaft 5 rotates counterclockwise, resulting in an opening and closing characteristic opposite to that of the first specification throttle device 1A.

[0039] In the throttle devices 1A and 1B of this embodiment, the boss portion 25 provided in the gear housing chamber 4 is shared between the first and second specifications. The throttle valve 7 is opened by moving the lever portion 19d of the first driven gear 15 in opposite directions, using the first fully closed stopper 23 or the second fully closed stopper 30, which are configured based on this boss portion 25, as a reference. As a result, the trajectories L1 and L2 of the lever portion 19d in each specification are also formed in opposite directions with respect to the boss portion 25. In the second specification, the adjustment screw 27 is positioned in a different orientation than in the first specification in order to contact the lever portion 19d, which moves to the fully closed position on the second trajectory L2. Specifically, in the throttle device 1A of the first specification, the tip of the adjustment screw 27 was oriented clockwise, as described with reference to Figure 6. In contrast, in the throttle device 1B of the second specification, the adjustment screw 27 is maintained in a different orientation with its tip oriented counterclockwise, as will be described later with reference to Figure 10.

[0040] Next, prior to describing the throttle device 1B of the second specification, we will describe the second full-open stopper 31 provided in the gear housing chamber 4 for the second specification. Considering that the lever portion 19d of the second specification moves along the second trajectory L2, the second fully open stopper 31 is provided on the second trajectory L2. Specifically, as shown in Figures 8, 9, and 10, the second fully open stopper 31 is integrally formed so as to protrude to the right from within the annular recess 2a4 beyond the bottom wall 2a1, at a position slightly above and forward of the axis C1 of the throttle shaft 5, so that the lever portion 19d moving along the trajectory L2 makes contact with it when the throttle valve 7 reaches the fully open position.

[0041] [Second specification throttle device 1B] Next, we will explain the throttle device 1B of the second specification. Figure 10 is a side view corresponding to Figure 6, showing the throttle valve 7 of the second specification throttle device 1B fully closed; Figure 11 is a cross-sectional view corresponding to Figure 7, showing the throttle valve 7 fully closed; and Figure 12 is an exploded perspective view corresponding to Figure 5.

[0042] Although most components are shared between the first specification throttle device 1A and the second specification throttle device 1B, including the sharing of the left throttle body 2 which is the essence of the present invention, some components with different shapes are used because the opening and closing direction of the throttle valve 7 is reversed. To explain this point, as can be seen from the comparison between Figure 5 and Figure 12, the components in question are the first driven gear 15 and the second driven gear 32, and the first return spring 20 and the second return spring 33.

[0043] In the second driven gear 32, the positional relationship between the sector-type gear portion 19 and the lever portion 19d centered on axis C1 is reversed compared to the first driven gear 15. Therefore, in both the first driven gear 15 and the second driven gear 32, the sector-type gear portion 19 can be engaged with the next intermediate gear 14 while the lever portion 19d can contact the fully closed stoppers 23 and 31.

[0044] Furthermore, the winding direction of the second return spring 33 is reversed compared to that of the first return spring 20. As shown in Figure 10, the right end of the second return spring 33 is hooked onto the lever portion 19d, and the left end is hooked onto the second spring hook 35, which is integrally formed at a rear position relative to the axis C1 of the throttle shaft 5 within the annular recess 2a4. Therefore, both the first return spring 20 and the second return spring 33 can bias the throttle valve 7 to the closed position.

[0045] The second specification throttle device 1B is assembled as shown in Figures 10 and 11. The only difference from the first specification is that the opening and closing direction of the throttle valve 7 (the rotation direction of the throttle shaft 5) is reversed, but the basic configuration and operation are the same as the first specification. For this reason, only a brief explanation is given, but together with the second driven gear 32, the throttle shaft 5 rotates in both forward and reverse directions under the drive of the motor 9 while being biased by the second return spring 33. Accordingly, the lever portion 19d moves along the second trajectory L2, which is an arc shape centered on the axis C1 of the throttle shaft 5, as shown by the thick arrow in Figure 10.

[0046] In this embodiment, the distance from the axis C1 to the respective stopper portions 19d of the first and second driven gears 15 and 32, in other words, the radii of the first trajectory L1 and the second trajectory L2 centered on the axis C1 are set to be equal. Consequently, the boss portion 25, the first fully open stopper 24, and the second fully open stopper 31, which function as the first or second fully closed stopper 23 and 30, are arranged on the first trajectory L1 or the second trajectory L2, respectively, which have the same radius centered on the throttle shaft 5.

[0047] If the components were not arranged on a trajectory of the same radius, each component would be dispersed radially on the bottom wall 2a1 around the axis C1, which could lead to an increase in the size of the gear housing 4 and, consequently, the throttle devices 1A and 1B. By arranging the components as described above, such problems can be avoided, and the effect of miniaturizing the throttle devices 1A and 1B can be obtained.

[0048] On the other hand, as described above, in the second specification throttle device 1B, the tip of the adjustment screw 27 is directed counterclockwise. To this end, as shown in Figure 10, a second screw hole 34 is formed in the boss portion 25 so as to penetrate the boss portion 25 from the outer second planar portion 25b to the inner second planar portion 25d, and the outer second planar portion 25b and the inner second planar portion 25d are formed to be perpendicular to the axis C5 of this second screw hole 34. As a result, the tip of the adjustment screw 27 screwed into the second screw hole 34 protrudes into the gear housing chamber 4 from the inner first planar portion 25d of the boss portion 25 and is directed counterclockwise, while the base end protrudes to the outside of the left throttle body 2 from the outer second planar portion 25b of the boss portion 25, and the lock nut 28 is tightened to restrict the rotation of the adjustment screw 27.

[0049] In reality, when the left throttle body 2 is die-cast, neither screw holes 26 nor 34 of any specification are formed in the boss portion 25. Then, after the specifications of throttle devices 1A and 1B are determined, the corresponding screw holes 26 and 34 are formed and the adjustment screws 27 and lock nuts 28 are assembled.

[0050] In the second specification throttle device 1B configured in this way, the second fully closed stopper 30 allows the fully closed position of the throttle valve 7 to be arbitrarily adjusted, thereby adjusting the engine's idle speed. Furthermore, the second fully closed stopper 30 restricts the fully closed position of the throttle valve 7, enabling the controller to perform opening degree learning based on the fully open and fully closed positions.

[0051] As described above, the fully closed stoppers 23 and 30 of the throttle devices 1A and 1B in this embodiment are boss portions 25 that protrude from the inside and outside of the gear housing chamber 4, and have two pairs of substantially parallel planar portions 25a, 25b, 25c, and 25d, and are capable of forming screw holes 26 and 34 for passing the adjustment screw 27. Therefore, the left throttle body 2 can be shared between the two specifications, and the left throttle body 2 can be molded with a single mold, thus reducing the cost of manufacturing the mold. Due to these factors, the manufacturing cost of the throttle devices 1A and 1B can be reduced.

[0052] Furthermore, the gear case 16 of the gear housing chamber 4 has two bosses integrally formed for the full-open stoppers 24 and 31. Therefore, in the first specification, the first full-open stopper 24 can restrict the fully open position of the throttle valve 7, and in the second specification, the second full-open stopper 31 can restrict the fully open position of the throttle valve 7.

[0053] Furthermore, spring hooks 21 and 35 are provided in two locations in the gear housing chamber 4. Therefore, in the first specification, the left end of the first return spring 20 can be hooked onto the first spring hook 21 to bias the throttle valve 7 in the closing direction, and in the second specification, the left end of the second return spring 33 can be hooked onto the second spring hook 35 to bias the throttle valve 7 in the closing direction.

[0054] Furthermore, the boss portion 25 has a roughly rhombic shape in cross-section. Therefore, adjacent outer first planar portion 25a and outer second planar portion 25b have equivalent areas, and adjacent inner first planar portion 25c and inner second planar portion 25d have equivalent areas. As a result, screw holes 26 and 34 are formed in the boss portion 25, making it easy to pass the adjustment screw 27 through.

[0055] By the way, in this embodiment, the first and second spring hooks 21 and 35 are individually provided in the gear housing chamber 4, but it is not necessarily required to adopt this configuration. For example, they may be shared by a single spring hook 41, as shown in Alternative Example 1 below.

[0056] [Another example 1] Figure 13 is a side view corresponding to Figure 6, showing the case where the throttle device of Alternative Example 1 is assembled as the first specification, and Figure 14 is a side view corresponding to Figure 10, showing the case where the throttle device of Alternative Example 1 is assembled as the second specification. The shared spring hook 41 is integrally formed at an intermediate position centered on the axis C1 between the original first spring hook 21 and the second spring hook. In the first specification, the left end of the first return spring 20 is hooked, and in the second specification, the left end of the second return spring 33 is hooked. The intermediate position is to equalize the biasing force acting on the first driven gear 15 and the biasing force acting on the second driven gear 32. According to this alternative example 1, by using a single spring hook 41, the shape of the left throttle body 2 can be further simplified, and consequently, a further reduction in manufacturing costs can be achieved. Note that the number of spring hooks 21, 35, and 41 is not limited to the embodiment and alternative example 1, and may be three or more depending on the spring constant required for the return springs 20 and 33.

[0057] On the other hand, in this embodiment, a sector-type first driven gear 15 and a second driven gear 32 were selectively used depending on the specifications of the throttle devices 1A and 1B, but it is not necessarily required to adopt this configuration. For example, a single driven gear 51 may be used for both, as shown in alternative example 2 below.

[0058] [Another example 2] Figure 15 is an exploded perspective view corresponding to Figure 5, showing the driven gear 51 of alternative example 2. The gear portion 19 of the shared driven gear 51 is not sector-type, but rather has teeth formed all around its outer circumference, similar to a typical gear. Figure 15 shows the case of the first specification, but even with such a driven gear 51, the driving force of the next intermediate gear 14 can be transmitted to the throttle shaft 5 without any problems, and the same is true for the second specification, although it is not shown in the figure. Furthermore, by sharing the driven gear 51, it is no longer necessary to individually injection mold gear portions 19 of different shapes, and since they can be molded with a single mold, a further reduction in manufacturing costs can be achieved.

[0059] The embodiments of the present invention are not limited to these embodiments. For example, in the above embodiments, the invention is embodied in throttle devices 1A and 1B for a two-cylinder engine, and a gear housing chamber 4 is provided between the left and right throttle bodies 2 and 3, but the invention is not limited to this. For example, it may be applied to a throttle device for a single-cylinder engine, and a gear housing chamber 4 may be provided on either the left or right side of the throttle body, with a boss portion 25 and first and second fully open stoppers 24 and 31 provided inside. [Explanation of symbols]

[0060] 1A, 1B Throttle device 2 Left throttle body 2b Throttle bore 4 Gear storage chamber 5. Throttle shaft 7. Throttle valve 15 First driven gear 19d Lever section 21. First spring hook 23. First fully closed stopper 24. First full-throttle stopper 25 Boss Section 25a Outer first plane part (first plane part) 25b Outer second plane part (second plane part) 25c Inner 1st plane part (1st plane part) 25d Inner 2nd plane part (2nd plane part) 26 First screw hole 27 Adjust Screw 30. Second fully closed stopper 31. Second full-open stopper 32 Second driven gear 34 Second screw hole 35. Second spring hook 41 Spring Hook 51 Passed gear

Claims

1. Throttle body and, A throttle shaft fixed to the driven gear, A throttle valve that is opened and closed via the throttle shaft within the throttle bore, A lever portion provided on the driven gear, A fully closed stopper that restricts the lever portion to the fully closed position, A throttle device comprising a full-open stopper that restricts the lever portion to the fully open position, The fully closed stopper is a boss portion provided to protrude from the inside and outside of the gear housing chamber, and has two pairs of substantially parallel surfaces, forming a screw hole for passing the adjustment screw. A throttle device characterized by the following features.

2. The gear case of the gear housing chamber is provided with two bosses integrally formed in place for fully opening stoppers. The throttle device according to feature 1.

3. The gear housing chamber is provided with one or more spring hooks. The throttle device according to feature 1.

4. The aforementioned boss portion is roughly rhombic in cross-section. The throttle device according to feature 1.

5. The boss portion has a first flat portion and a second flat portion formed therein, which function as seating surfaces for a lock nut that restricts the rotation of the adjustment screw, and space is secured around each of them. The throttle device according to feature 1.

6. When the driven gear rotates in one direction, an adjustment screw is installed on the first flat surface. The throttle device according to feature 1.

7. When the driven gear rotates in another direction, an adjustment screw is installed on the second flat surface. The throttle device according to feature 1.

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