Engine throttle device

Abstract

To provide a throttle device of an engine which can easily execute fitting operation for a support shaft for supporting an intermediate gear into a positioning hole and engaging operation of the intermediate gear and a mating gear, when connecting a throttle body side assembly and a gear cover side assembly, which are individually assembled.SOLUTION: A driven gear 14 of a throttle shaft 4, a driving gear 16 of a motor 15, and an intermediate gear 19 supported by a support shaft 17 are stored between a throttle body side assembly 26 and a gear cover side assembly 27. The support shaft 17 has one end 17a fixed to a gear case 9 of the throttle body side assembly 26 and is formed with a positioning hole 20 into which the other end 17b of the support shaft 17 is inserted accompanying connection of the assemblies 26, 27 in a gear cover 10 of the gear cover side assembly 27. A projection length L1 of the other end 17b of the support shaft 17 from an end face of the intermediate gear 19 is set to be longer than a projection length L2 of the driving gear 16 from an opening surface of the positioning hole 20.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present invention relates to a throttle device for an engine that drives a throttle valve to open and close by an electric motor.

Background Art

[0002] As a throttle device for an engine, for example, Patent Document 1 discloses a device in which a transmission chamber is defined between a throttle body and a gear cover, and an electric motor and a reduction gear are housed inside. The reduction gear includes a pinion gear fixed to the electric motor, a final gear fixed to the valve shaft, and an intermediate gear supported by a support shaft. The large-diameter gear portion of the intermediate gear meshes with the pinion gear, and the small-diameter gear portion meshes with the final gear. One end of the support shaft supporting the intermediate gear is press-fitted into the gear cover, the flange of the electric motor to which the pinion gear is fixed is temporarily fixed with screws, and the circuit board is fixed with screws.

[0003] With such a configuration, in the state of the gear cover alone, press-fitting of the support shaft of the intermediate gear, temporary fixing of the flange of the electric motor, screwing of the circuit board, etc. can be carried out, and it can be assembled as an assembly on the gear cover side. Therefore, when assembling the throttle device, the assembly work of the assembly on the gear cover side can be carried out in parallel with the assembly work of the assembly on the throttle body side that attaches the valve shaft etc. to the throttle body, thereby improving the production efficiency. Also, when connecting the assembled throttle body side assembly and the gear cover side assembly, while housing the electric motor on the gear cover side in the recess on the throttle body side, the other end of the support shaft of the intermediate gear on the gear cover side is inserted into the positioning hole on the throttle body side.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

[0005] However, the throttle device described in Patent Document 1 had the problem that it was difficult to perform the operation of joining the throttle body side assembly and the gear cover side assembly.

[0006] In other words, when joining the assembled parts together, it is necessary not only to insert the other end of the support shaft on the gear cover side into the positioning hole on the throttle body side, but also to engage the small-diameter gear portion of the intermediate gear supported by the support shaft with the final gear on the throttle body side. For this reason, during the joining process, the gear cover is brought closer to the throttle body while the other end of the support shaft is inserted into the positioning hole and the small-diameter gear portion is engaged with the final gear.

[0007] To mesh the small-diameter gear section with the final gear, it is necessary to maintain the correct relative position of the gears, in other words, the correct gear pitch, and to finely adjust the relative angle so that the peaks and valleys of the gears correspond. While performing these operations, the other end of the support shaft must be inserted into the positioning hole in parallel, and the operator may not be able to visually check the meshing state of the gears or the positional relationship between the support shaft and the positioning hole because the gear cover obstructs their view. As a result, the joining of the throttle body assembly and the gear cover assembly required a highly difficult and complicated operation.

[0008] The present invention was made to solve these problems, and its objective is to provide an engine throttle device that allows for easy insertion of the support shaft for the intermediate gear into the positioning hole and meshing of the intermediate gear with the mating gear when joining the individually assembled throttle body side assembly and gear cover side assembly. [Means for solving the problem]

[0009] To achieve the above objective, the engine throttle device of the present invention comprises a throttle body side assembly, in which a throttle valve is supported on a throttle shaft so as to be able to open and close relative to the throttle body, and a gear cover side assembly, in which a motor is attached to a gear cover, and houses a driven gear fixed to the end of the throttle shaft, a drive gear fixed to the output shaft of the motor, and an intermediate gear supported by a pivot shaft that transmits the rotation of the drive gear to the driven gear, in an engine throttle device in which one end of the pivot shaft is attached to the gear case S It is fixed in place and assembled to the throttle body side together with the intermediate gear. body The intermediate gear is configured to drive the gear cover assembly as the throttle body assembly and the gear cover assembly are coupled. Ya and They bite together, Gi Yakaba - The throttle body assembly and the gear cover assembly are joined together, and the other end of the support shaft is inserted into a positioning hole. The protrusion length of the other end of the support shaft from the end face of the intermediate gear is such that the positioning hole opens. Gear cover Drive gear from the opening surface Ya Set to be longer than the protrusion length The motor is mounted to the gear cover in a position where the output shaft is oriented in the direction of the opening of the positioning hole. It is characterized by the following:

[0010] Other forms include support shaft The insertion length after inserting into the positioning hole is longer than the protrusion length of the drive gear from the opening surface where the positioning hole opens. good.

[0011] Other forms include, The protruding length of the other end of the support shaft is set by adding a value greater than the sum of the protruding length of the drive gear and the length of the chamfer formed on the other end of the support shaft and the length of the chamfer formed on the opening of the positioning hole. good.

[0012] In other embodiments, the intermediate gear may consist of a large-diameter portion that meshes with the drive gear and a small-diameter portion arranged parallel to the gear case side of the large-diameter portion and meshing with the driven gear, wherein the protrusion length of the other end of the support shaft from the end face of the large-diameter portion is set to be longer than the protrusion length of the drive gear from the opening surface of the gear cover through which the positioning hole is opened.

[0016] In another embodiment, the intermediate gear may be one of a plurality of gears that mesh with each other to transmit the rotation of the drive gear to the driven gear. [Effects of the Invention]

[0017] According to the throttle device of the engine of the present invention, when coupling the throttle body side assembly and the gear cover side assembly assembled individually, the fitting operation of the support shaft for supporting the intermediate gear into the positioning hole and the meshing operation between the intermediate gear and the mating gear can be easily performed.

Brief Description of the Drawings

[0018] [Figure 1] It is a perspective view showing the throttle device of the engine of the embodiment. [Figure 2] It is a perspective view of the throttle device seen from another angle. [Figure 3] It is an exploded perspective view showing the gear unit. [Figure 4] It is a side view showing the meshing state of each gear in the gear housing chamber with the gear cover removed. [Figure 5] It is a cross-sectional view taken along the line V-V of FIG. 4 showing the meshing state of each gear in the gear housing chamber. [Figure 6] It is a cross-sectional view showing a state where the throttle body side assembly and the gear cover side assembly are opposed to each other. [Figure 7] It is a cross-sectional view showing a state where the throttle body side assembly and the gear cover side assembly are approaching each other to be coupled. [Figure 8] It is an explanatory view showing a state where the motor attached to the gear case is positioned using a jig. [Figure 9] It is a cross-sectional view corresponding to FIG. 6 showing a throttle device of Another Example 1 in which an intermediate gear and a support shaft are provided on the gear case side. [Figure 10] It is a cross-sectional view corresponding to FIG. 7 showing the throttle device of Another Example 1. [Figure 11] It is a side view corresponding to FIG. 4 showing a throttle device of Another Example 2 provided with a pair of intermediate gears.

Embodiments for Carrying Out the Invention

[0019] The following describes one embodiment of an engine throttle device embodying the present invention. 《Overall Structure》 Figure 1 is a perspective view showing the throttle device of the engine in this embodiment, and Figure 2 is a perspective view of the throttle device from a different angle. The throttle device 1 of this embodiment is mounted on a single-cylinder engine used as a power source for a motorized bicycle. The throttle body 2 of the throttle device 1 has a throttle bore 2a formed through it, which communicates with the inside of the engine cylinder (not shown). When mounted on a vehicle, one end of the throttle bore 2a is connected to an air cleaner, and the other end is connected to the engine's intake manifold, and the intake air filtered by the air cleaner is supplied to the inside of the engine cylinder via the throttle bore 2a and the intake manifold.

[0020] A throttle valve 3 is supported within the throttle bore 2a by a throttle shaft 4 so as to be able to open and close. The throttle shaft 4 is driven by a gear unit 6 attached to the throttle body 2, which opens and closes the throttle valve 3 to adjust the amount of intake air. In Figures 1 and 2, 6 is a throttle opening sensor that detects the opening degree of the throttle valve 3, and 7 is an intake pressure outlet connected to an intake pressure sensor (not shown). In the following description, the direction along the axis C3 of the throttle shaft 4 may be referred to as the throttle axis direction.

[0021] Gear Unit 6 Next, we will explain the details of the gear unit 6. Figure 3 is an exploded perspective view showing the gear unit 6, Figure 4 is a side view showing the meshing state of each gear in the gear housing with the gear cover removed, and Figure 5 is a cross-sectional view of the VV line in Figure 4 showing the meshing state of each gear in the gear housing. A gear case 9 is attached to one side of the throttle body 2 along the throttle axis, and a gear cover 10 is fastened to the gear case 9 by screws 8, defining a gear housing chamber 11 inside. One end of the throttle shaft 4 protrudes into the gear housing chamber 11, and a driven gear 14 is fastened to it via a washer 13 by a bolt 12. A motor 15 is disposed in a motor chamber 10a formed in the gear cover 10, and its output shaft 15a protrudes into the gear housing chamber 11 along an axis C1 parallel to the axis C3 of the throttle shaft 4, and a drive gear 16 is fixed to it. The gear case 10 may be integrally formed with the throttle body 2.

[0022] Within the gear housing chamber 11, a support shaft 17 is positioned between the driven gear 14 and the drive gear 16. The support shaft 17 is maintained in a position along an axis C2 parallel to the axis C3 of the throttle shaft 4, and one end 17a is press-fitted into a press-fit hole 18 that penetrates the gear case 9. An intermediate gear 19 is rotatably supported on the support shaft 17, and the other end 17b of the support shaft 17 protrudes from the end face of the intermediate gear 19 toward the gear cover 10 and is fitted into a positioning hole 20 formed in the gear cover 10. The intermediate gear 19 consists of a large-diameter portion 19a that meshes with the drive gear 16, and a small-diameter portion 19b that is integrally arranged alongside the large-diameter portion 19a on the gear case 9 side and meshes with the driven gear 14. Therefore, the rotation of the drive gear 16 by the motor 15 is transmitted to the large-diameter portion 19a of the intermediate gear 19, and further transmitted to the driven gear 14 from the small-diameter portion 19b.

[0023] Within the gear housing chamber 11, a return spring 22 is wound around the throttle shaft 4, biasing the throttle valve 3 in the closing direction together with the throttle shaft 4. When the driven gear 14 rotates in the closing direction due to the return spring 22, one side of it comes into contact with the stopper portion 23 in the gear housing chamber 11, restricting its rotation and thereby keeping the throttle valve 3 in the fully closed position. While receiving the biasing force of the return spring 22, the throttle valve 3 is opened and closed via the gears 14, 16, 19 and the throttle shaft 4 according to the rotation direction of the drive gear 16 driven by the motor 15.

[0024] A pair of contacts 15b of the motor 15 are electrically connected to a connector 24 provided on the gear case 9. When mounted on a vehicle, a harness extending from the vehicle-side controller is connected to the connector 24, and the controller controls the motor 15 to open and close the throttle valve 3 according to the amount of throttle operation of the vehicle.

[0025] 《Dimensional setting for each part for joining the assembly》 As will be described in detail later, the throttle device 1 of this embodiment employs a procedure in which the assembly work on the throttle body 2 side and the gear cover 10 side is carried out in parallel, and then the two sides are joined together after the completion of each assembly. The throttle body 2 is fitted with the throttle valve 3, throttle shaft 4, driven gear 14, gear case 9, support shaft 17, and intermediate gear 19, and the assembled state will hereafter be referred to as the throttle body side assembly 26. The gear cover 10 is fitted with the motor 15 and drive gear 16, and the assembled state will hereafter be referred to as the gear cover side assembly 27.

[0026] Figure 6 is a cross-sectional view showing the throttle body assembly 26 and the gear cover assembly 27 facing each other, and Figure 7 is a cross-sectional view showing the throttle body assembly 26 and the gear cover assembly 27 brought close to each other in order to connect them. When connecting the throttle body assembly 26 and the gear cover assembly 27, it is necessary to insert the other end 17b of the support shaft 17 of the throttle body assembly 26 into the positioning hole 20 of the gear cover assembly 27, and to engage the large diameter portion 19a of the intermediate gear 19 supported by the support shaft 17 with the drive gear 16 of the gear cover assembly 27.

[0027] To facilitate this coupling operation, in the throttle axial direction, when the protrusion length of the other end 17b of the support shaft 17 from the end face of the large diameter portion 19a of the intermediate gear 19 is L1, and the protrusion length of the drive gear 16 from the opening surface of the gear cover 10 where the positioning hole 20 is opened is L2, the protrusion length L1 is set to be longer than the protrusion length L2 (L1>L2). Specifically, in this embodiment, considering the length l1 of the chamfered portion 28 formed on the other end 17b of the support shaft 17, and the length l2 of the chamfered portion 29 formed at the opening of the positioning hole 20, the protrusion length L1 is set by adding a value L3 that is larger than the sum of lengths l1 and l2 to the protrusion length L2 (L1=L2+L3, L3>l1+l2).

[0028] 《Joining operations of assemblies 26 and 27, and the effects achieved》 The assembly of each completed assembly, 26, 27, is carried out in the following procedure. As shown in Figure 6, the throttle body assembly 26 and the gear cover assembly 27 are positioned opposite each other. In this arrangement, the other end 17b of the support shaft 17 and the opening of the positioning hole 20 face each other, and the outer circumference of the large diameter portion 19a of the intermediate gear 19 faces the outer circumference of the drive gear 16. As the assemblies 26 and 27 are brought closer together, the other end 17b of the support shaft 17 first begins to fit into the positioning hole 20, and then, as shown in Figure 7, when the insertion length of the support shaft 17 into the positioning hole 20 reaches value L3, the large diameter portion 19a of the intermediate gear 19 and the drive gear 16 begin to mesh.

[0029] As the assemblies 26 and 27 approach each other, the insertion length of the support shaft 17 increases beyond L3, and the meshing length between the large-diameter portion 19a and the drive gear 16 in the throttle axis direction gradually increases. Then, as shown in Figure 5, when the gear case 9 and the gear cover 10 are joined, the large-diameter portion 19a of the intermediate gear 19 and the drive gear 16 are fully meshed, and the joining process is completed when the gear case 9 and the gear cover 10 are fastened with screws 8.

[0030] As described above, during the process of bringing the assemblies 26 and 27 closer together, the other end 17b of the support shaft 17 begins to fit into the positioning hole 20 prior to the meshing of the large-diameter portion 19a of the intermediate gear 19 with the drive gear 16. Therefore, from this point onward, the support shaft 17 functions as a so-called positioning pin, determining the positional relationship between the large-diameter portion 19a of the intermediate gear 19 and the drive gear 16, in other words, the gear pitch, and the meshing operation between the large-diameter portion 19a and the drive gear 16 is performed in this state.

[0031] In the throttle device described in Patent Document 1, when joining the assemblies, it is necessary to perform the operation of inserting the support shaft into the positioning hole and the operation of meshing the gears in parallel. Moreover, during the meshing operation, it is necessary to finely adjust the relative angle while maintaining the correct positional relationship between the small-diameter gear section and the final gear, and these factors made the assembly joining process difficult.

[0032] In contrast, in this embodiment, it is not necessary to simultaneously insert the support shaft 17 into the positioning hole 20 and mesh the gears, allowing the operator to concentrate on each operation. Furthermore, since the gear meshing operation is performed with the gear pitch fixed by inserting the support shaft 17 into the positioning hole 20, the operator can easily initiate the meshing of the gears with a simple operation of fine-tuning the relative angle between the large-diameter portion 19a and the drive gear 16, without paying particular attention to the positional relationship between them.

[0033] In addition, even after the gears begin to mesh, the gear pitch is maintained by the support shaft 17, guiding the assemblies 26 and 27 to approach each other, making it easy to connect the gear case 9 and the gear cover 10 in the correct position. While the worker is working, the gear cover 10 may obstruct their view of the meshing state of the gears and the positional relationship between the support shaft 17 and the positioning hole 20, but even in such situations, both the insertion operation and the meshing operation can be easily performed.

[0034] In particular, in this embodiment, chamfered portions 28 and 29 are formed on the other end 17b of the support shaft 17 and on the opening of the positioning hole 20, respectively, in order to facilitate insertion of the support shaft 17 into the positioning hole 20. Therefore, in the process of bringing the assemblies 26 and 27 closer together, the timing at which the support shaft 17 begins to fit into the positioning hole 20 is delayed by an amount equivalent to the lengths l1 and l2 of the chamfered portions 28 and 29. In other words, if there are no chamfered portions 28 and 29, the protruding length L1 of the shaft 17 can be made longer than the protruding length L2 of the drive gear 16, allowing the support shaft 17 to begin to fit into the positioning hole 20 prior to the start of meshing between the gears. However, if chamfered portions 28 and 29 are formed, the effective protruding length L1 of the support shaft 17 is reduced by an amount equivalent to the lengths l1 and l2 of the chamfered portions 28 and 29.

[0035] Therefore, in this embodiment, the protruding length L1 is set by adding a value L3 that is greater than the sum of lengths l1 and l2, l1+l2, to the protruding length L2. Accordingly, as described with reference to Figure 7, when the gears begin to mesh, the support shaft 17 is reliably fitted into the positioning hole 20, thereby achieving the advantages related to the gear meshing operation described above. However, the protruding length L1 may be set to a value sufficiently larger than the protruding length L2 without considering the specific lengths l1 and l2 of the chamfered portions 28 and 29.

[0036] On the other hand, the motor 15 of the gear cover assembly 27 is mounted on the gear cover 10 with its output shaft 15a facing the direction in which the positioning hole 20 of the gear cover 10 opens. In other words, since the positioning hole 20 and the output shaft 15a are oriented in the same direction, the motor 15 can be positioned using the jig 30, as shown in Figure 8. More specifically, in order to maintain the correct gear pitch between the drive gear 16 and the intermediate gear 19, the motor 15 needs to be fixed in an appropriate position on the gear cover 10 with respect to the positioning hole 20. The jig 30 has positioning pins 30a and positioning holes 30b formed at intervals corresponding to the gear pitch. The positioning pins 30a are inserted into the positioning holes 20 of the gear cover 10, and the positioning holes 20 are fitted into the output shaft 15a of the motor 15. This adjusts the motor 15 to the correct position, and if the motor 15 is fixed in this state, the positioning hole 20 and the output shaft 15a can be maintained at the correct gear pitch.

[0037] In this embodiment, the intermediate gear 19 and the support shaft 17 are provided on the throttle body side assembly 26, and upon coupling with the gear cover side assembly 27, the support shaft 17 is fitted into the positioning hole 20 of the gear cover 10, and the large diameter portion 19a of the intermediate gear 19 is meshed with the output shaft 15a of the motor 15. However, the present invention is not limited to this, and for example, the intermediate gear 19 and the support shaft 17 may be provided on the gear cover side assembly 27, which will be described below as Alternative Example 1. In this Alternative Example 1 and Alternative Example 2 described later, parts with the same configuration as the embodiment are given the same part numbers and their descriptions are omitted, and the differences will be described in detail.

[0038] 《Another example 1》 Figure 9 is a cross-sectional view corresponding to Figure 6, showing a throttle device 1 of alternative example 1 in which the intermediate gear 19 and support shaft 17 are provided on the gear case 9 side, and Figure 10 is a cross-sectional view corresponding to Figure 7, showing a throttle device 1 of alternative example 1. In this embodiment, the gear cover 10 has a press-fit hole 41 instead of the positioning hole 20, and one end 17a of the support shaft 17 is press-fitted into this press-fit hole 41. An intermediate gear 19 is rotatably supported on the support shaft 17, and its large-diameter portion 19a meshes with the drive gear 16. Therefore, in this alternative example 1, the gear cover side assembly 27 is composed of the gear cover 10, motor 15, drive gear 16, intermediate gear 19, and support shaft 17.

[0039] Furthermore, the gear case 9 has a positioning hole 42 instead of the press-fit hole 18 of the embodiment, and when the assemblies 26 and 27 are joined, the other end 17b of the support shaft 17 is press-fitted into this positioning hole 42. Thus, in this alternative example 1, the throttle body side assembly 26 is composed of the throttle valve 3, throttle shaft 4, driven gear 14, and gear case 9.

[0040] In this alternative example 1, when joining assemblies 26 and 27, it is necessary to insert the other end 17b of the support shaft 17 of the gear cover side assembly 27 into the positioning hole 42 of the throttle body side assembly 26, and to engage the small diameter portion 19b of the intermediate gear 19 supported by the support shaft 17 with the driven gear 14 of the throttle body side assembly 26. Therefore, in the throttle axial direction, when the protrusion length of the other end 17b of the support shaft 17 from the end face of the small diameter portion 19b of the intermediate gear 19 is L1, and the protrusion length of the driven gear 14 from the opening surface of the gear case 9 where the positioning hole 42 opens is L2, the protrusion length L1 is set to be longer than the protrusion length L2 (L1 > L2). Alternatively, as in the embodiment, the protrusion length L1 may be set based on a value L3 that takes into account the chamfered portion 28 of the other end 17b of the support shaft 17 and the chamfered portion 29 of the opening of the positioning hole 42.

[0041] As the assemblies 26 and 27 are brought closer together, the other end 17b of the pivot shaft 17 begins to fit into the positioning hole 42. As shown in Figure 10, once the pivot shaft 17 is partially inserted into the positioning hole 42, the small diameter portion 19b of the intermediate gear 19 and the driven gear 14 begin to mesh. Therefore, without repeating the explanation, the operation of inserting the pivot shaft 17 into the positioning hole 42 and the meshing of the gears can be performed sequentially, allowing the operator to concentrate on each operation. Furthermore, since the gear meshing operation is performed with the gear pitch fixed by inserting the pivot shaft 17 into the positioning hole 42, the gears can be easily meshed together.

[0042] Furthermore, the motor 15, which is provided on the gear cover side assembly 27, is mounted on the gear cover 10 with its output shaft 15a facing in the direction in which the support shaft 17 of the gear cover 10 protrudes. For this reason, although not shown in the figures, the motor 15 can be positioned using a jig similar to the jig 30 of the embodiment, which has a positioning hole for inserting the support shaft 17 and a positioning hole for engaging with the output shaft 15a.

[0043] By the way, in this embodiment, the rotation of the drive gear 16 is transmitted to the driven gear 14 via a single intermediate gear 19, but this is not the only way. For example, the rotation may be transmitted via multiple intermediate gears, which will be explained below as alternative example 2.

[0044] 《Another example 2》 Figure 11 is a side view corresponding to Figure 4, showing another example 2 throttle device 1 with a pair of intermediate gears. The rotation of the drive gear 16 is transmitted to the first intermediate gear 51, which functions as an idler gear, and further transmitted to the large-diameter portion 52a of the second intermediate gear 52. The rotation of the small-diameter portion 52b of the second intermediate gear 52 is transmitted to the driven gear 14, which in turn opens and closes the throttle valve 3 together with the throttle shaft 4.

[0045] In a throttle device 1 with such a configuration, if, for example, only the drive gear 16 is provided on the gear cover side assembly 27, the drive gear 16 will mesh with the first intermediate gear 51 when the assemblies 26 and 27 are coupled. Alternatively, if both the drive gear 16 and the first intermediate gear 51 are provided on the gear cover side assembly 27, the first intermediate gear 51 will mesh with the large diameter portion 52a of the second intermediate gear 52 when the assemblies 26 and 27 are coupled.

[0046] Furthermore, when the drive gear 16, the first intermediate gear 51, and the second intermediate gear 52 are provided on the gear cover side assembly 27, the small diameter portion 52b of the second intermediate gear 52 engages with the driven gear 14 when the assemblies 26 and 27 are joined together. Although we will not repeat the explanation, in either case, if the protrusion lengths L1 and L2 are set in the same manner as in the embodiment, the same effects and advantages can be achieved.

[0047] This concludes the description of the embodiments, but the aspects of the present invention are not limited to these embodiments. For example, in the above embodiment, the invention was embodied in a throttle device 1 having a single throttle bore 2 mounted on a motorized bicycle, but it is not limited to this and can be applied to throttle devices of engines mounted on various vehicles. Furthermore, the throttle device of the present invention may be applied to engines used for purposes other than as a power source for driving, such as engines for generators. Moreover, it may be embodied as a multi-throttle device having multiple throttle bores. [Explanation of symbols]

[0048] 1. Throttle device 2 Throttle Body 3. Throttle shaft 4. Throttle valve 9 Gear case 10 Gear cover 11 Gear storage chamber 14 Passed gear 15 Motor 15a Output shaft 16 Drive gear 17 Spindle 17a one end 17b Other end 19 Intermediate gear 19a Large diameter section 19b Small diameter section 20,42 Positioning holes 26 Throttle body side assembly 27 Gear cover side assembly 51. Second intermediate gear (intermediate gear)

Claims

1. In an engine throttle device comprising a throttle body side assembly, in which a throttle valve is supported on the throttle body by a throttle shaft so as to be able to open and close, and a gear cover side assembly, in which a motor is attached to a gear cover, the throttle device comprises a gear housing chamber defined between a gear case provided on the throttle body and the gear cover, which houses a driven gear fixed to the end of the throttle shaft, a drive gear fixed to the output shaft of the motor, and an intermediate gear supported by a pivot shaft that transmits the rotation of the drive gear to the driven gear, The aforementioned support shaft is fixed at one end to the gear case and, together with the intermediate gear, constitutes the throttle body side assembly. The intermediate gear meshes with the drive gear of the gear cover assembly when the throttle body assembly and the gear cover assembly are coupled together. The gear cover is provided with a positioning hole into which the other end of the support shaft is inserted when the throttle body side assembly and the gear cover side assembly are joined. The protrusion length of the other end of the support shaft from the end face of the intermediate gear is set to be longer than the protrusion length of the drive gear from the opening surface of the gear cover through which the positioning hole is opened. The motor is mounted to the gear cover in a position where the output shaft is oriented in the direction in which the positioning hole opens. An engine throttle device characterized by the following:

2. The insertion length of the support shaft after it has been inserted into the positioning hole is longer than the protrusion length of the drive gear from the opening surface through which the positioning hole is made. The throttle device for an engine according to feature 1.

3. The protruding length of the other end of the support shaft is set by adding to the protruding length of the drive gear a value greater than the sum of the length of the chamfer formed on the other end of the support shaft and the length of the chamfer formed in the opening of the positioning hole. The throttle device for an engine according to feature 1.

4. The intermediate gear consists of a large-diameter portion that meshes with the drive gear and a small-diameter portion arranged parallel to the large-diameter portion on the gear case side that meshes with the driven gear. The length of the other end of the support shaft protruding from the end face of the large-diameter portion is set to be longer than the length of the drive gear protruding from the opening surface of the gear cover through which the positioning hole is opened. The throttle device for an engine according to feature 1.

5. The intermediate gear is one of a plurality of gears that mesh with each other to transmit the rotation of the drive gear to the driven gear. The throttle device for an engine according to feature 1.

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