Throttle device for engine

Abstract

To provide a throttle device capable of preventing interference with a vehicle side part by shortening a hose length and reducing manufacturing cost.SOLUTION: A first throttle body 2 on one side and a second throttle body 3 on the other side are connected to each other across a gear case 5 storing a gear train, and throttle valves 8 are opened and closed in a throttle bore 6a to 6c through the gear train and a throttle shaft 7. Connection ports 26c and 27c provided on the other side of the gear case 5 of the first throttle body 2, a first internal path 26a for communicating the throttle bore 6b of the first throttle body 2 with the connection port 26c, and a second internal path 27a for communicating the throttle bore 6c of the second throttle body 3 with the connection port 27c are provided, and the second internal path 27a is provided in the first and second throttle bodies 2 and 3 and the gear case 5 so as to extend from the throttle bore to the first throttle body 2 through the gear case 5. 6c.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to an engine throttle device. [Background technology]

[0002] For example, Patent Document 1 discloses a throttle device for a four-cylinder engine, in which a pair of throttle bodies are connected to each other with a gear case containing a gear train in between. A throttle valve is disposed in a throttle bore extending through each throttle body and supported by a throttle shaft, and the driving force of a motor fixed to the gear case is transmitted to the throttle shaft via the gear train to open and close each throttle valve.

[0003] Hoses for various purposes are connected to each throttle bore. For example, if information about intake pressure is needed for engine fuel injection control, one end of a pressure detection hose is connected to the pressure output nipple of each throttle bore, and the hoses are grouped together and the other end is connected to a common intake pressure sensor. The pressure of the intake air flowing through each throttle bore is transmitted to the intake pressure sensor via the pressure detection hose and detected as intake pressure. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2007-64068 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, the throttle device of Patent Document 1 has a problem in that the pressure detection hose is long. That is, the gear case that houses the gear train has a shape that protrudes outward, i.e., in a direction perpendicular to the axis of the throttle shaft, making it difficult to position the intake pressure sensor in a position that coincides with the gear case in the axial direction of the throttle shaft, and as a result, the intake pressure sensor is positioned at a distance from the gear case in the axial direction.

[0006] If the intake pressure sensor is positioned axially in line with the gear case, the pressure detection hoses from each throttle bore can be routed to the intake pressure sensor in the shortest possible distance. However, if the intake pressure sensor is spaced apart from the gear case as described above, the pressure detection hoses must be extended accordingly. A long pressure detection hose can swing due to acceleration and engine vibrations associated with vehicle acceleration, deceleration, and cornering, and can be damaged by frequent contact with surrounding vehicle components, thereby reducing the reliability of the throttle device. Furthermore, taking measures to prevent contact, such as fixing the hoses, increases manufacturing costs, and the increased hose length also contributes to increased costs.

[0007] The present invention has been made to solve these problems, and its purpose is to provide an engine throttle device that can shorten the length of pressure detection hoses, etc., thereby preventing interference with surrounding vehicle components, improving reliability, and reducing manufacturing costs. [Means for solving the problem]

[0008] In order to achieve the above object, the throttle device for an engine of the present invention comprises a first throttle body arranged on one side of a gear case containing a gear train and a second throttle body arranged on the other side, which are connected to each other, throttle valves arranged in throttle bores defined in each of the first and second throttle bodies being supported by a throttle shaft, and the driving force of the motor being transmitted to the throttle shaft via the gear train to open and close each throttle valve, characterized in that the throttle device comprises a connection port provided at a position on the other side of the gear case of the first throttle body, a first internal passage connecting the inside of the throttle bore of the first throttle body to the connection port, and a second internal passage connecting the inside of the throttle bore of the second throttle body to the connection port, the second internal passage being drilled through each of the first and second throttle bodies and the gear case so as to extend from the throttle bore of the second throttle body through the gear case to the first throttle body.

[0009] In another aspect, the gear case may be formed by overlapping a mating surface around the first gear case portion provided on the first throttle body side with a mating surface around the second gear case portion provided on the second throttle body side, with the mating surface maintained airtight from the outside by an annular gasket, and the second internal passage connects a third internal passage formed in the first throttle body and the first gear case portion with a fourth internal passage formed in the second throttle body and the second gear case portion via the mating surfaces, and the gasket may be integrally formed with an auxiliary seal portion that surrounds the periphery of the connection point of the third and fourth internal passages and maintains airtightness from the outside.

[0010] In another aspect, the connection ports may be provided as a pair of independent connection ports in the first throttle body, a first internal passage extending from the throttle bore of the first throttle body and one end connected to one of the connection ports, and a second internal passage extending from the throttle bore of the second throttle body and one end connected to the other of the connection ports.

[0011] In another aspect, the connection port may be provided as a single connection port in the first throttle body, and the first internal passage and the second internal passage may merge via a junction within the first throttle body and be connected to the connection port.

[0012] In another aspect, the first throttle body may further include an intake pressure sensor disposed at a location on the other side of the gear case and connected to the connection port, and the first and second internal passages may function as pressure passages that transmit the intake pressure in the throttle bores of the first and second throttle bodies to the intake pressure sensor.

[0013] In another aspect, the connection port may be configured to be connected to a charcoal canister, and the first and second internal passages may function as evaporator passages that guide evaporated gas adsorbed in the charcoal canister into the throttle bores of the first and second throttle bodies. [Effects of the Invention]

[0014] According to the engine throttle device of the present invention, the length of the pressure detection hose and the like can be shortened, thereby preventing interference with surrounding vehicle components, improving reliability, and reducing manufacturing costs. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a perspective view showing a throttle device according to an embodiment of the present invention; [Figure 2] FIG. 2 is a cross-sectional view taken along line II-II in FIG. [Figure 3] FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2. [Figure 4] FIG. 2 is an exploded perspective view of the throttle body. [Figure 5] FIG. 5 is a detailed view of part A in FIG. 4. [Figure 6] FIG. 4 is an enlarged cross-sectional view of FIG. 3 showing a pressure passage. [Figure 7] FIG. 7 is an enlarged cross-sectional view corresponding to FIG. 6, showing a first modified example in which the #2 and #3 internal passages are joined together. [Figure 8] FIG. 5 is a cross-sectional view corresponding to FIG. 3, showing a second modified example in which an evaporator passage is formed as an internal passage. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, an embodiment of the present invention will be described, in which the present invention is embodied in a throttle device for a three-cylinder engine mounted on a motorcycle. FIG. 1 is a perspective view showing the throttle device of this embodiment, FIG. 2 is a cross-sectional view taken along line II-II in FIG. 1, FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2, and FIG. 4 is an exploded perspective view with the throttle body separated. In each drawing, the front-rear, left-right, and up-down directions are shown with the driver in the vehicle as the subject, and when the throttle device 1 is mounted on the engine of the vehicle, the throttle device 1 is maintained in the position shown in each drawing. In the following explanation, the front-rear, left-right, and up-down directions are expressed assuming that the throttle device 1 is mounted on the vehicle.

[0017] The throttle body of the throttle device 1 is made by joining together a first throttle body 2 disposed on the left and a second throttle body 3 disposed on the right, and each throttle body 2, 3 is manufactured as an aluminum die-cast molded product. The left side corresponds to "one side" in this invention, and the right side corresponds to "the other side" in this invention.

[0018] A first gear case portion 2a, which opens to the right, is integrally formed at the right end of the first throttle body 2. A flat, annular mating surface 2b, which faces right, is formed around the first gear case portion 2a, and a similarly annular seal groove 2c is formed on this mating surface 2b, into which a packing 4 is fitted. A second gear case portion 3a, which opens to the left, is integrally formed at the left end of the second throttle body 3. A flat, annular mating surface 3b, which faces left, is formed around the second gear case portion 3a.

[0019] The first and second gear case portions 2a, 3a are fastened together with screws 15 with mating surfaces 2b, 3b overlapping each other, and these gear case portions 2a, 3a form a gear case 5. As a result, the first and second throttle bodies 2, 3 are joined to each other with the gear case 5 in between. A gear accommodating chamber 5a is defined within the gear case 5 and is kept airtight from the outside by the packing 4.

[0020] Two throttle bores 6 extend through the first throttle body 2 in the front-rear direction, and one throttle bore 6 extends through the second throttle body 3 in the front-rear direction, with the throttle bores 6 arranged side by side at intervals in the left-right direction. In the following explanation, the throttle bores will be distinguished from one another by being referred to from left to right as #1 throttle bore 6a, #2 throttle bore 6b, and #3 throttle bore 6c. Although not shown, when the throttle device 1 is mounted on a vehicle, the front ends of the #1 to #3 throttle bores 6a to 6c are connected to the respective cylinders of the engine, and the rear ends are connected to the air cleaner.

[0021] A throttle shaft 7 is rotatably supported in the first and second throttle bodies 2, 3, penetrating each of the throttle bores 6a to 6c and the gear accommodating chamber 5a from side to side. A throttle valve 8 is disposed in each of the throttle bores 6a to 6c, and is supported by the throttle shaft 7 so as to be able to open and close.

[0022] FIG. 5 is a detailed view of part A in FIG. As shown in Figures 3 to 5, a motor housing 9 is integrally formed below the #2 throttle bore 6b of the first throttle body 2, and a motor 10 is housed within the motor housing 9. An output shaft 10a of the motor 10 protrudes into the gear housing 5a, and a drive gear 11 is fixed to it. An intermediate gear 12 is rotatably supported by a support shaft 14 above the drive gear 11 within the gear housing 5a, and this intermediate gear 12 is integrally formed with a large-diameter gear portion 12a and a small-diameter gear portion 12b. The large-diameter gear portion 12a of the intermediate gear 12 meshes with the drive gear 11, and the small-diameter gear portion 12b meshes with a sector-type driven gear 13 fixed to the throttle shaft 7. As a result, when the engine is running, the driving force of the motor 10 is transmitted to the throttle shaft 7 via a gear train consisting of a drive gear 11, an intermediate gear 12, and a driven gear 13, and the amount of intake air supplied to the engine through the throttle bores 6a to 6c is adjusted according to the opening and closing of each throttle valve 8.

[0023] Fuel injection valves 16 are attached to the tops of the first and second throttle bodies 2, 3, respectively, corresponding to the #1 to #3 throttle bores 6a to 6c, and a common delivery pipe 17 is connected to each fuel injection valve 16. A nipple 17a is provided at the left end of the delivery pipe 17, and when the throttle device 1 is mounted on a vehicle, the nipple 17a is connected to the vehicle's fuel tank via a fuel hose (not shown), and fuel is supplied to each fuel injection valve 16 via the fuel hose and delivery pipe 17.

[0024] As shown in FIG. 3 , evaporative gas introduction nipples 18 are provided on the tops of the first and second throttle bodies 2, 3 so as to communicate with the #1 to #3 throttle bores 6a to 6c, respectively. One end of an evaporator hose 19 is connected to each of the evaporative gas introduction nipples 18, and the evaporator hoses 19 are connected to one another. A nipple 19a is provided on one end of the evaporative hose 19, and when the throttle device 1 is mounted on a vehicle, a charcoal canister of an evaporative gas treatment system (not shown) is connected to the nipple. As is well known, evaporated gas generated in the fuel tank while the engine is stopped is adsorbed in the charcoal canister. Then, utilizing the negative pressure generated in the intake manifold when the engine starts, evaporated gas from the charcoal canister is diverted through the evaporator hose 19 and guided into the #1 to #3 throttle bores 6a to 6c, where it is combusted and treated in the engine cylinders.

[0025] A throttle sensor 20 is attached to the right end of second throttle body 3. Although not shown, throttle sensor 20 is connected to the right end of throttle shaft 7 and detects the rotation angle of throttle shaft 7, in other words, the opening of throttle valve 8 as the throttle opening. An intake air temperature sensor 21 is attached to the left end of first throttle body 2. Although not shown, intake air temperature sensor 21 protrudes into #1 throttle bore 6a and detects the temperature of the intake air flowing therethrough as the intake air temperature.

[0026] An intake pressure sensor 22 is disposed in the first throttle body 2 between the #1 throttle bore 6a and the #2 throttle bore 6b, and is attached to the first throttle body 2 with screws (not shown). As will be described below, the intake pressure sensor 22 communicates with each of the #1 to #3 throttle bores 6a to 6c via a pressure passage 23, and the pressure of the intake air flowing through each of the throttle bores 6a to 6c is transmitted to the intake pressure sensor 22 and detected as the intake pressure.

[0027] When the throttle device 1 is mounted on a vehicle, couplers of a harness extending from an engine controller on the vehicle body are connected to the connectors 20a-22a provided on each of the sensors 20-22, the connector 10b of the motor 10 protruding from the side of the gear case 5, and the connector 16a provided on each of the fuel injection valves 16. As a result, detection information from each of the sensors 20-22 is input to the controller, and a drive signal from the controller is input to each of the fuel injection valves 16 to control the amount and timing of fuel injection into each cylinder of the engine. The drive signal from the controller is also input to the motor 10, which adjusts the opening of each throttle valve 8 and, ultimately, the amount of intake air supplied to the cylinders of the engine.

[0028] Next, the pressure passage 23 that connects the intake pressure sensor 22 with each of the throttle bores 6a to 6c will be described in detail. FIG. 6 is an enlarged cross-sectional view of FIG. 3 showing the pressure passage 23. 3 and 5, the pressure passage 23 is made up of #1 to #3 pressure passages 25 to 27 extending from the #1 to #3 throttle bores 6a to 6c, a joint member 28 that joins the #1 to #3 pressure passages 25 to 27, and a sensor-side hose 29 that connects the joint member 28 to the intake pressure sensor 22. The #1 to #3 pressure passages 25 to 27 are also formed by connecting the #1 to #3 internal passages 25a to 27a and the #1 to #3 hoses 25b to 27b via the #1 to #3 nipples 25c to 27c, respectively.

[0029] The #1 internal passage 25a of the #1 pressure passage 25 is drilled in the first throttle body 2, extends downward from the #1 throttle bore 6a and is connected to a #1 nipple 25c located directly below. One end of the #1 hose 25b is connected to the #1 nipple 25c, and the other end is connected to a connection port 28a of a joint member 28.

[0030] The #2 internal passage 26a of the #2 pressure passage 26 is drilled in the first throttle body 2, extends downward from the #2 throttle bore 6b and is connected to a #2 nipple 26c located directly below. One end of the #2 hose 26b is connected to the #2 nipple 26c, and the other end is connected to a connection port 28b of a joint member 28. The #2 nipple 26c corresponds to the "connection port" of this invention, and the #2 internal passage 26a of the #2 pressure passage 26 corresponds to the "first internal passage" of this invention.

[0031] The #3 internal passage 27a of the #3 pressure passage 27 is drilled through the first throttle body 2, the second throttle body 3, and the gear case 5 interposed therebetween. More specifically, the #3 internal passage 27a extends from the #3 throttle bore 6c of the second throttle body 3 through the gear case 5 to the first throttle body 2 and is connected to a #3 nipple 27c provided adjacent to the #2 nipple 26c. One end of a #3 hose 27b is connected to the #3 nipple 27c, and the other end is connected to a connection port 28c of a joint member 28. The #3 nipple 27c corresponds to the "connection port" of this invention, and the #3 internal passage 27a of the #3 pressure passage 27 corresponds to the "second internal passage" of this invention.

[0032] On the other hand, the connection port 28 d of the joint member 28 is connected to the intake pressure sensor 22 via a sensor-side hose 29 . In addition, restrictors 30 are provided at the tips of the #1 to #3 nipples 25c to 27c, which suppress fluctuations in the intake pressure transmitted to the intake pressure sensor 22 and prevent mutual interference of the intake pressures between the throttle bores 6a to 6c which are connected to each other via the pressure passage 23.

[0033] The #3 internal passage 27a of the #3 pressure passage 27 will now be described in more detail. 5 and 6, the #3 internal passage 27a connects a third internal passage 27a-1 formed in the first throttle body 2 and the first gear case portion 2a to a fourth internal passage 27a-2 formed in the second throttle body 3 and the second gear case portion 3a. To connect the third and fourth internal passages 27a-1 and 27a-2, an extension portion 32 is formed on the mating surfaces 2b and 3b of the gear case portions 2a and 3a, an auxiliary seal groove 33 is formed in the seal groove 2c, and an auxiliary seal portion 34 is formed in the packing 4.

[0034] The expansion portion 32 is formed by expanding the front portion of the annular mating surfaces 2b, 3b inward in a local arc shape, and is flat and flush with the mating surfaces 2b, 3b. The auxiliary seal groove 33 is formed along the periphery of the expansion portion 32, and its upper and lower portions are connected to the seal groove 2c to form an annular shape. An auxiliary seal portion 34 is integrally formed with the packing 4 so as to have a shape corresponding to the auxiliary seal groove 33.

[0035] The fourth internal passage 27a-2 has one end that extends diagonally downward and to the left from the connected #3 throttle bore 6c, and the other end that opens onto the expanded portion 32 of the mating surface 3b. The third internal passage 27a-1 has one end that opens onto the expanded portion 32 of the mating surface 2b, extends horizontally to the left, and the other end that is connected to the #3 nipple 27c. As a result, the third and fourth internal passages 27a-1, 27a-2 are connected to each other via the expanded portions 32 of the mating surfaces 2b, 3b, and the periphery of this connection is surrounded by the auxiliary seal 34 to maintain an airtight seal from the outside.

[0036] Next, the effects of the throttle device 1 configured as above will be described. Similar to the throttle device 1 of Patent Document 1, the throttle device 1 of this embodiment has a pair of throttle bodies 2, 3 connected to each other with a gear case 5 sandwiched therebetween. Because the gear case 5, which houses the gear train, has a shape that protrudes outward, the intake pressure sensor 22 is disposed in a position that avoids the gear case 5 in the left-right direction, specifically, between the #1 throttle bore 6a and the #2 throttle bore 6b, spaced to the left of the gear case 5, and the joint member 28 connected to the intake pressure sensor 22 is also disposed in the same left-right position. As a result, the rightmost #3 throttle bore 6c and the joint member 28 are separated by a large left-right distance.

[0037] Therefore, if the #3 pressure passage 27 were entirely made of hoses, a longer hose would be required compared to, for example, the #1 hose 25b and the #2 hose 26b. Furthermore, as shown by the two-dot chain line in FIG. 3 , the hoses must be routed around the gear case 5, which also contributes to the increased hose length. Furthermore, a long hose is more susceptible to vibrations caused by acceleration and engine vibrations associated with vehicle acceleration, deceleration, and cornering, and is more likely to be damaged by frequent contact with surrounding vehicle components. Furthermore, taking measures to prevent contact, such as fixing the hoses, would increase manufacturing costs, and the increased hose length would also contribute to increased costs.

[0038] Therefore, in this embodiment, most of the #3 pressure passage 27, specifically the region from the #3 throttle bore 6c to the #3 nipple 27c, is formed as a #3 internal passage 27a, which is drilled through the first and second throttle bodies 2, 3 and the gear case 5. This region of the #3 internal passage 27a does not vibrate like a hose even when subjected to vehicle acceleration or engine vibration. Furthermore, although the region other than the #3 internal passage 27a is made up of the #3 hose 27b, this hose is short and therefore does not vibrate easily even when subjected to acceleration or engine vibration, eliminating the need for contact prevention measures and enabling short hoses to be manufactured inexpensively.

[0039] As a result, according to the throttle device 1 of this embodiment, the length of the #3 hose 27b for pressure detection can be shortened, thereby preventing interference with surrounding vehicle components, improving reliability, and reducing manufacturing costs.

[0040] In addition, because the #3 internal passage 27a is formed without detouring the gear case 5, the path length of the #3 pressure passage 27 from the #3 throttle bore 6c to the joint member 28 can be shortened compared to when the hose is routed around it, which provides another advantage of improving the accuracy of intake air pressure detection.

[0041] In particular, in this embodiment, an extension 32 is formed in the front portion of the annular mating surfaces 2b, 3b, and the third and fourth internal passages 27a-1, 27a-2 are connected via this extension 32. The longitudinal position of this extension 32 substantially coincides with the downstream side of the throttle valve 8 in the #3 throttle bore, i.e., the opening position of the fourth internal passage 27a-2 in the #3 throttle bore. Therefore, the third and fourth internal passages 27a-1, 27a-2 are formed without unnecessary longitudinal bends, which further shortens the path length of the #3 pressure passage 27, thereby contributing to improved intake pressure detection accuracy.

[0042] Meanwhile, an extension portion 32 is formed on the mating surfaces 2b, 3b of the gear case portions 2a, 3a, and this extension portion 32 connects the third internal passage 27a-1 and the fourth internal passage 27a-2. An auxiliary seal portion 34 is integrally formed with the packing 4 that keeps the gear accommodating chamber 5a liquid-tight, and this auxiliary seal portion 34 keeps the connection portion of the third and fourth internal passages 27a-1, 27a-2 airtight. An O-ring is generally used to keep the connection portion of such third and fourth internal passages 27a-1, 27a-2 airtight, but this increases the number of parts and makes assembling the small O-ring a complicated task.

[0043] According to this embodiment, the number of parts can be reduced by integrally forming the auxiliary seal portion 34 with the packing 4. Furthermore, when the packing 4 is fitted into the seal groove 2c, the auxiliary seal portion 34 is automatically fitted into the auxiliary seal groove 33, so the connection points of the third and fourth internal passages 27a-1, 27a-2 can be kept airtight without complicating the assembly work. These points contribute to reducing the manufacturing costs of the throttle device 1.

[0044] However, the third internal passage 27a-1 and the fourth internal passage 27a-2 do not necessarily have to be connected at the mating surfaces 2b, 3b of the gear case portions 2a, 3a. For example, the third and fourth internal passages 27a-1, 27a-2 may be connected within the gear accommodating chamber 5a, which corresponds to the inner circumferential side of the mating surfaces 2b, 3b, separately. Because the gear accommodating chamber is an open space, for example, one of the third and fourth internal passages 27a-1, 27a-2 may be formed into a pipe shape and protrude toward the other within the gear accommodating chamber 5a, with its tip connected to the other internal passage 27a-1, 27a-2, and then an O-ring or the like may be used to maintain airtightness.

[0045] In the present embodiment, the #2 internal passage 26a of the #2 pressure passage 26 and the internal passage 27a of the #3 pressure passage 27 are formed independently of each other and connected to the joint member 28 via the #2 nipple 26c and the #3 nipple 27c, respectively, as connecting parts, but this is not limitative. For example, the #2 internal passage 26a and the #3 internal passage 27a may be joined together and connected to the joint member 28 via a common nipple, and this embodiment will be described as Modified Example 1.

[0046] FIG. 7 is an enlarged cross-sectional view corresponding to FIG. 6, showing a first modified example in which the #2 and #3 internal passages 26a and 27a are joined together. In this modified example 1, the #3 nipple 27c, the #3 hose 27b, and the connection port 28c of the joint member 28 are omitted. A fourth internal passage 27a-2 of the #3 internal passage 27a extends leftward within the first throttle body 2 and merges with the #2 internal passage 26a via a junction 101. As a result, the #3 internal passage 27a is connected to the #2 nipple 26c along with the #2 internal passage 26a. The #2 nipple 26c does not include a restrictor 30, and instead, a restrictor member 102, which performs a similar function, is press-fitted into the #2 internal passage 26a and the fourth internal passage 27a-2 of the #3 internal passage 27a.

[0047] In the modified example 1 configured as above, the same effects as those of the embodiment can be achieved, although a redundant description will not be given. Additionally, in this modified example 1, the #3 nipple 27c, the #3 hose 27b, and the connection port 28c of the joint member 28 can be omitted to reduce the number of parts, which provides the advantage of further reducing the manufacturing cost of the throttle device 1.

[0048] Meanwhile, in this embodiment, the #3 internal passage 27a functions as the pressure passage 23 that transmits the intake pressure to the intake pressure sensor 22, but this is not limited to this. For example, instead of the evaporator hose 19, an internal passage may be formed to function as an evaporator passage that guides evaporated gas from the charcoal canister into the throttle bores 6a to 6c, and this embodiment will be described as Modified Example 2.

[0049] FIG. 8 is a cross-sectional view corresponding to FIG. 3, showing a second modified example in which the evaporator passage is formed as an internal passage. To put it simply, in this modified example 2, the functions of the evaporator hose 19 and the pressure passage 23 of the embodiment are interchanged without changing the configurations of these two. Therefore, in this modified example 2, the evaporator hose 19 described in the embodiment functions as an intake pressure detection hose 201, and an intake pressure sensor 22 is connected to its nipple 201a, so that the pressure of the intake air flowing through the #1 to #3 throttle bores 6a to 6c is transmitted to the intake pressure sensor 22 via the intake pressure detection hose 201 and detected as the intake pressure.

[0050] Furthermore, in this modified example 2, the pressure passage 23 described in the embodiment functions as an evaporator passage 202. Therefore, when the throttle device 1 is mounted on a vehicle, a charcoal canister of an evaporated gas treatment system (not shown) is connected to a nipple 202a of the evaporator passage 202 instead of the intake pressure sensor 22. Then, when the engine starts operating, the evaporated gas in the charcoal canister is diverted via the evaporator passage 202 by utilizing the negative pressure generated in the intake manifold and is guided into the #1 to #3 throttle bores 6a to 6c, where it is combusted and treated in the cylinders of the engine.

[0051] 3, the evaporator hose 19 must be routed around the gear case 5, which increases the length of the route and causes it to oscillate due to vehicle acceleration and engine vibrations. This increases the risk of damage due to frequent contact with surrounding vehicle components, and taking measures to prevent contact, such as fixing the hose, increases manufacturing costs, and the increase in hose length also contributes to increased costs.

[0052] In this variant 2, the #3 internal passage 27a constituting the evaporator passage 202 is drilled through the first and second throttle bodies 2, 3 and the gear case 5, so although a redundant explanation will not be given, the above-mentioned drawbacks can be eliminated and the same effects as those of the embodiment can be achieved.

[0053] The aspects of the present invention are not limited to the embodiments and other examples. For example, in the above embodiment, the throttle device 1 is embodied in a three-cylinder engine mounted on a motorcycle, but the types of vehicles and engines to which the present invention is applied are not limited to this and can be changed as desired.

[0054] In the above embodiment, the first and second throttle bodies 2, 3 are each manufactured as a molded product by aluminum die-casting, with the first gear case portion 2a integrally formed with the first throttle body 2 and the second gear case portion 3a integrally formed with the second throttle body 3, but this is not limited to this. For example, the first gear case portion 2a and the second gear case portion 3a may be manufactured from aluminum or synthetic resin material as separate parts from the first and second throttle bodies 2, 3 and fixed to the respective throttle bodies 2, 3 with screws or the like. Even in this case, the #3 internal passage 27a is drilled through the first and second throttle bodies 2, 3 and the first gear case portion 2a and the second gear case portion 3a, respectively, as in the embodiment, and similar effects are achieved. [Explanation of symbols]

[0055] 1 Throttle device 2. First throttle body 2a First gear case 2b, 3b mating surface 3 Second throttle body 3a Second gear case 4. Gasket 5 Gear case 6b #2 throttle bore 6c #3 throttle bore 7 Throttle shaft 8 Throttle valve 10 Motor 23 Pressure passage 26a #2 internal passage (1st internal passage) 26c #2 nipple (connection port) 27a #3 internal passage (2nd internal passage) 27a-1 3rd internal passage 27a-2 4th internal passage 27c #3 nipple (connection port) 34 Auxiliary seal part 101 Junction 202 Evaporator passage

Claims

1. A throttle device in which a first throttle body disposed on one side of a gear case accommodating a gear train and a second throttle body disposed on the other side are connected to each other, throttle valves disposed in throttle bores defined in the first and second throttle bodies respectively are supported by a throttle shaft, and driving force of a motor is transmitted to the throttle shaft via the gear train to open and close each of the throttle valves, a connection port provided at a position of the first throttle body on the other side of the gear case; a first internal passage that connects the inside of the throttle bore of the first throttle body with the connection port; a second internal passage that connects the inside of the throttle bore of the second throttle body with the connection port; Equipped with The second internal passage is formed in each of the first and second throttle bodies and the gear case so as to extend from the throttle bore of the second throttle body through the gear case to the first throttle body. An engine throttle device characterized by:

2. the gear case is formed by overlapping a peripheral mating surface of a first gear case portion provided on the first throttle body side with a peripheral mating surface of a second gear case portion provided on the second throttle body side in a state in which the mating surfaces are kept airtight from the outside by an annular packing, the second internal passage connects a third internal passage formed in the first throttle body and the first gear case portion and a fourth internal passage formed in the second throttle body and the second gear case portion to each other via the mating surfaces, The packing is integrally formed with an auxiliary seal portion that surrounds the periphery of the connection point of the third and fourth internal passages and maintains airtightness from the outside.

2. The engine throttle device according to claim 1.

3. the connection ports are provided as a pair of independent connection ports on the first throttle body, the first internal passage extends from the throttle bore of the first throttle body and has one end connected to one of the connection ports, The second internal passage extends from the throttle bore of the second throttle body, and one end of the second internal passage is connected to the other end of the connection port.

3. The engine throttle device according to claim 1 or 2.

4. the connection port is provided on the first throttle body as a single connection port, The first internal passage and the second internal passage join together via a joining portion within the first throttle body and are connected to the connection port.

3. The engine throttle device according to claim 1 or 2.

5. an intake pressure sensor disposed at a position on the other side of the first throttle body relative to the gear case and connected to the connection port; The first and second internal passages function as pressure passages that transmit the intake pressure in the throttle bores of the first and second throttle bodies to the intake pressure sensor.

3. The engine throttle device according to claim 1 or 2.

6. The connection port is connected to a charcoal canister, The first and second internal passages function as evaporator passages that guide evaporated gas adsorbed in the charcoal canister into the throttle bores of the first and second throttle bodies.

3. The engine throttle device according to claim 1 or 2.

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