JP5030934B2 - Breathing structure of control case in engine intake control system - Google Patents

Description

  The present invention includes an intake cylinder that has an intake passage and supports a throttle valve that opens and closes the intake passage, a throttle body that is connected to one side of the intake cylinder, and a housing that is accommodated in the control case. And a throttle opening / closing control device for controlling the opening / closing of the throttle valve, and a mounting flange having an end face that opens the downstream end of the intake passage is formed on the intake cylinder, and the mounting flange is fastened to the throttle body support portion. In addition, the present invention relates to an intake control device for an engine in which an O-ring surrounding the downstream end of the intake passage is interposed between the end face of the mounting flange and the throttle body support portion. It relates to the breathing structure of the control case that allows the accompanying breathing.

In a conventional engine intake control device, as disclosed in Patent Document 1 below, a gasket is interposed between a mounting flange of a throttle body and a throttle body support portion that fastens the mounting flange. It is known to provide a breathing groove on the end face that is in close contact with the gasket so that the inside of the control case communicates with the outer surface of the mounting flange.
Japanese Patent No. 3744377

  In the above conventional structure, the entire end face of the mounting flange formed with the breathing groove is in intimate contact with the gasket, so even if car wash water or rainwater is splashed around the mounting flange, the water is blocked by the gasket and enters the breathing groove. It does not enter easily.

  By the way, the above-mentioned gasket is effective in ensuring airtightness between the throttle body mounting flange and the throttle body support when the throttle body support is made of a highly rigid metal. When it is made of a synthetic resin having a lower rigidity than metal, it may be more effective to secure an airtightness between the mounting flange and the throttle body support part by interposing an O-ring. However, in such a case, the sealability between the mounting flange and the throttle body support portion cannot be expected on the outer side of the O-ring. Therefore, as disclosed in Patent Document 1, the mounting flange covers the throttle body support portion. Even if a breathing groove is provided in the part where the car wash water or rain water is applied around the mounting flange, the water enters the breathing groove through a slight gap between the mounting flange and the throttle body support, and is further controlled. There is a risk of intrusion into the case.

  The present invention has been made in view of such circumstances, and an intake air of an engine in which an O-ring surrounding the downstream end of the intake passage is interposed between the end face of the throttle body mounting flange and the throttle body support portion. In a control device, to provide a breathing structure for a control case that can prevent intrusion of car wash water or the like into the control case while enabling the breathing in the control case using the end face of the mounting flange. Objective.

  In order to achieve the above object, the present invention provides a throttle body including an intake passage, an intake cylinder supporting a throttle valve for opening and closing the intake path, and a control case connected to one side of the intake cylinder. And a throttle opening / closing control device that is housed in the control case and controls the opening / closing of the throttle valve, and a mounting flange having an end face that opens the downstream end of the intake passage is formed on the intake cylinder. In the engine intake control device, wherein an O-ring surrounding the downstream end of the intake passage is interposed between the end face of the mounting flange and the throttle body support portion. A vent hole for communicating a portion of the end face covered with the throttle body support portion outside the O-ring into the control case, and the vent hole The ventilation groove on the end face that is open to the atmosphere constitutes a breathing path that communicates with the atmosphere in the control case, and the end face is opened above the breathing path and one end is opened to the outer face of the mounting flange. A first feature is that a water escape groove is provided in which the other end closes to the O-ring and becomes a dead end. The throttle body support portion corresponds to the support flange 31 of the intake manifold M in an embodiment of the present invention described later.

  According to the present invention, in addition to the first feature, the ventilation groove on the end surface intersects the first groove extending downward from the ventilation hole and the lower end of the first groove, and one end thereof is the mounting flange. A second feature is that the second groove is formed with a second groove that opens to the outer surface of the first groove and extends beyond the intersection with the first groove.

  In addition to the second feature of the present invention, the vent hole includes a bottomed large-diameter hole that opens at the end surface, a bottom surface of the large-diameter hole, and a small-diameter hole that opens at both ends in the control case. And a step is provided between the bottom surface of the large-diameter hole and the groove bottom of the first groove and between the groove bottoms of the first groove and the second groove. To do.

  Furthermore, in addition to the first feature, the present invention has a fourth feature in that the water escape groove is inclined so that it is lowered toward the outer surface of the mounting flange.

  Furthermore, in addition to the second feature, the fifth feature of the present invention is that the second groove is inclined so as to descend toward the outer surface of the mounting flange.

  Furthermore, in addition to the second feature of the present invention, the mounting flange is fastened to the throttle body support portion by a bolt disposed outside the O-ring, and the second groove is formed on the upper surface of the bolt. It is a sixth feature that it is formed in an arc shape so as to line up along the line.

  According to the first aspect of the present invention, a vent hole communicating with the inside of the control case the portion of the end face of the mounting flange that is covered with the throttle body support portion outside the O-ring, and opens the vent hole to the atmosphere. The ventilation groove on the end face constitutes a breathing path that communicates with the atmosphere inside the control case, so that the inside of the control case breathes as the temperature changes, and overheats and dew condensation of the throttle throttle opening / closing control device. Can be prevented. Moreover, since the breathing path consisting of the vent and the groove forms a curved path, even if car wash water or rainwater enters the breathing path, the momentum of the water is attenuated at the bent part of the breathing path, The water can be prevented from entering the control case.

  In addition, the end face of the mounting flange is provided with a water release groove that opens at the outer surface of the mounting flange at the top of the breathing path and the other end closes to the O-ring. Even if car wash water or rainwater enters the minute gap between the end face of the mounting flange on the outside of the O-ring and the throttle body support section facing it above, Since it is trapped in the water escape groove and guided to the outside, it is possible to prevent the water from entering the breathing path and thus entering the control case.

  According to the second feature of the present invention, a plurality of bent portions of the respiratory path can be provided, and the momentum of the invading water from the outside can be effectively attenuated. In particular, the second groove is provided so that one end opens on the outer surface of the mounting flange and the other end extends beyond the intersection with the first groove. Even if it is poured into the water, the water can collide with the dead end of the second groove beyond the intersection with the first groove to effectively attenuate the momentum. Intrusion into the control case can be prevented more reliably.

  According to the third feature of the present invention, a step is provided between the bottom surface of the large-diameter hole and the groove bottom of the first groove, and between the groove bottom of the first groove and the second groove. The number of bent portions can be easily increased without specially extending the length of the path, and therefore the momentum of the invading water from the outside can be effectively attenuated while the respiratory path is made compact.

  According to the fourth aspect of the present invention, the water escape groove is inclined so as to descend toward the outer surface of the mounting flange, so that the trapped water can flow naturally and smoothly toward the outer surface of the mounting flange, It is possible to reliably prevent water from entering the respiratory tract.

  According to the fifth aspect of the present invention, since the second groove is inclined so as to descend toward the outer surface of the mounting flange, the water that has entered the second groove and has been attenuated is directed toward the outer surface of the mounting flange. It can flow naturally and smoothly, preventing water from entering the breathing path. According to the sixth aspect of the present invention, when the car wash water or rainwater enters the minute gap between the end face of the mounting flange and the throttle body support portion facing the bottom of the bolt, the bolt becomes a barrier. Thus, it is possible to prevent the water from entering the second groove, and hence the control case.

  Embodiments of the present invention will be described below on the basis of preferred embodiments of the present invention shown in the accompanying drawings.

  1 is a side view of an intake control device for an engine according to an embodiment of the present invention, FIG. 2 is a sectional view taken along line 2-2 in FIG. 1, FIG. 3 is an enlarged sectional view taken along line 3-3 in FIG. 4 is a sectional view taken along line 4-4, FIG. 5 is a sectional view taken along line 5-5 in FIG. 4, FIG. 6 is an enlarged vertical side view of a socket nut having a rotor of the throttle sensor in FIG. FIG. 8 is a sectional view taken along line 8-8 in FIG. 6, FIG. 9 is a schematic view of the default mechanism in FIG. 4, and FIG. 10 is an enlarged sectional view taken along line 10-10 in FIG.

  1 and 2, a support flange 31 is formed at the upstream end of the intake manifold 32 of an intake manifold M of a vehicle engine such as a motorcycle or an automobile. Is attached. The mounting structure will be described later. 1 and 2, the vertical direction is the vertical direction.

  As shown in FIG. 1, FIG. 2, FIG. 4, FIG. 5 and FIG. 9, the throttle body 1 includes an intake cylinder 1a having an intake passage 2 connected to the intake inlet 32 of the intake manifold M on the inside, and the intake cylinder 1a. The control case 1b is provided continuously from one side in the horizontal direction to the lower part. A throttle valve 3 for opening and closing the intake passage 2 is attached to the intake cylinder 1a. The valve shaft 3a of the throttle valve 3 crosses the intake passage 2 and is provided with bearings 4 and 5 on the left and right side walls of the throttle body 1. And is rotatably supported.

  A cap 6 that covers the outer end of the right end portion of the valve shaft 3 a and the bearing 5 is fitted to the right side wall of the throttle body 1. The left end portion of the valve shaft 3a protrudes outward from the left side wall of the throttle body 1, and an electric motor 8 for opening and closing the throttle valve 3 is connected to the protruding end portion via a reduction gear mechanism 9. The electric motor 8 is disposed in the control case 1b below the intake cylinder 1a, and the reduction gear mechanism 9 is disposed in the control case 1b on the side of the intake cylinder 1a.

  The reduction gear mechanism 9 includes a primary drive gear 11 fixed to the output shaft 10 of the electric motor 8, a primary driven gear 12 that is rotatably supported by the intermediate shaft 15 and meshes with the primary drive gear 11, and the primary drive gear 11. A secondary drive gear 13 integrally formed on one side of the driven gear 12 and a sector type secondary driven gear 14 fixed to the right end of the valve shaft 3a and meshing with the secondary drive gear 13 are provided. The rotation of the output shaft 10 of the motor 8 is decelerated in two steps and transmitted to the valve shaft 3a so that the throttle valve 3 can be opened and closed. Each gear of the reduction gear mechanism 9 is a spur gear, and the valve shaft 3a, the output shaft 10 and the intermediate shaft 15 are arranged such that their axes are aligned in parallel with each other perpendicular to the axis of the intake passage 2.

  The secondary driven gear 14 includes a mounting plate 14a that is molded and joined to the inner periphery of the secondary driven gear 14, and the mounting plate 14a is fitted to the right end portion of the valve shaft 3a so as to be non-rotating and screwed to the right end portion thereof. The nut 25 with the socket 25a to be attached is sandwiched between the annular step 7 on the valve shaft 3a. The secondary driven gear 14 is connected to a closing spring 17 made of a torsion coil spring that urges the secondary driven gear 14 in the closing direction of the throttle valve 3. In the schematic diagram of FIG. 9, the closing spring 17 is displayed as a coil spring for easy understanding.

  A stopper arm 18 is formed integrally with the secondary driven gear 14, and an idle stopper bolt 19 that receives the stopper arm 18 and regulates the idle opening of the throttle valve 3 is attached to the throttle body 1 in an adjustable manner. . A default lever 20 is rotatably supported on the valve shaft 3 a adjacent to the secondary driven gear 14. The secondary driven gear 14 is integrally formed with a contact arm 21 that contacts the default lever 20 and forcibly rotates the default lever 20 when the secondary driven gear 14 rotates to the closing side of the throttle valve 3. The lever 20 is connected to an opening spring 22 made of a coil spring that urges the lever 20 in the opening direction of the throttle valve 3 and is stronger than the closing spring 17. In FIG. 9, the opening spring 22 is displayed as a coil spring for easy understanding. When the default lever 20 is rotated in the opening direction of the throttle valve 3 by the biasing force of the opening spring 22, the default lever 20 drives the throttle valve 3 in the opening direction via the contact arm 21, that is, the secondary driven gear 14. At this time, a default stopper bolt 23 for receiving the default lever 20 and stopping the opening of the throttle valve 3 from the idle opening at a predetermined limp opening is attached to the throttle body 1 in an adjustable manner. Therefore, when the electric motor 8 is not energized during the operation of the engine, the default lever 20 is received by the default stopper bolt 23 by the biasing force of the opening spring 22 and the secondary driven by the biasing force of the closing spring 17. When the contact arm 21 of the gear 14 contacts the default lever 20, the throttle valve 3 is held at the default opening. This makes it possible to supply the engine with an intake air amount that enables the vehicle to travel at a low speed to the maintenance shop. The fixed ends of the closing spring 17 and the opening spring 22 are locked to the control case 1b. Thus, the default mechanism 24 is constituted by the default lever 20, the contact arm 21, the closing spring 17, the default lever 20, the opening spring 22 and the default stopper bolt 23.

  An inductance type throttle sensor 16 that detects the opening degree of the throttle valve 3 is connected to the valve shaft 3 a of the throttle valve 3. The throttle sensor 16 will be described with reference to FIGS. 4 and 6 to 8.

  A rotor holder 37 made of synthetic resin at the outer end of the nut 25 with the socket 25a screwed to the right end of the valve shaft 3a is molded. The rotor holder 37 has a hollow cylindrical shape that extends coaxially outward from the outer end of the nut 25 with the socket 25a, and the nut 25 with the socket 25a can be rotated through a hexagonal wrench in the hollow portion. ing. A rotor 16 a made of a magnetic plate is embedded in the front end surface of the rotor holder 37. The rotor 16 a includes three blades 16 a 2 that extend radially from the annular core portion 16 a 1, and the tips of the blades 16 a 2 slightly protrude from the outer peripheral surface of the rotor holder 37. An electronic control board 29 including a stator 16b that detects the rotation angle of the valve shaft 3a, that is, the opening degree of the throttle valve 3, in cooperation with the rotor 16a is attached to a control case 1b described later. Thus, the rotor 16a and the stator 16b constitute an inductance type throttle sensor 16. The default mechanism 24, the electric motor 8, the reduction gear mechanism 9, and the throttle sensor 16 constitute a throttle opening / closing control device A, and this throttle opening / closing control device A is accommodated in the control case 1b.

  Referring again to FIG. 4, the control case 1b includes an L-shaped case body 26 formed integrally with the intake cylinder 1a from one side surface of the intake cylinder 1a orthogonal to the valve shaft 3a, and from the left side surface to the lower side surface in FIG. The case cover 27 is joined to the open surface of the case body 26 by a plurality of screws 28. The joint surfaces of the case body 26 and the case cover 27 are orthogonal to the axis of the valve shaft 3a, and a seal member 30 is interposed between the joint surfaces. The electric motor 8 is housed in the lower part of the case body 26, the reduction gear mechanism 9 and the default mechanism 24 are housed in the case cover 27 to the case body 26, and the intermediate shaft 15 is disposed in the case body 26 and the case cover. Both ends are supported by 27.

  A structure for mounting the throttle body 1 to the intake manifold M will be described with reference to FIGS.

  The intake manifold M is made of synthetic resin, and a support flange 31 is integrally formed at its upstream end. The support flange 31 has a substantially square end surface 31a through which an intake inlet 32 of the intake manifold M is opened. A seal groove 33 surrounding the intake inlet 32 is provided on the end surface 31a. Is attached with an O-ring 34. Further, at the four corners surrounding the seal groove 33 of the support flange 31, the base end portion of the bolt 35 protruding from the end surface 31a is buried and fixed.

  On the other hand, a mounting flange 38 joined to the support flange 31 is integrally formed at the downstream end of the intake cylinder 1a of the throttle body 1. An end surface 38a of the mounting flange 38 facing the end surface 31a of the support flange 31 is also substantially square, and the downstream end of the intake passage 2 connected to the intake inlet 32 opens at the center. The mounting flange 38 is provided with a bolt insertion hole 39 at a position corresponding to the four bolts 35.

  Thus, when the throttle body 1 is attached to the intake manifold M, the bolt 35 of the support flange 31 is inserted into the bolt insertion hole 39 of the attachment flange 38, and the end face 38 a of the attachment flange 38 is used as the end face of the support flange 31. Accordingly, the O-ring 34 is brought into contact with the end face 38 a, and then the nut 36 is screwed and fastened to the tip of the bolt 35 penetrating the bolt insertion hole 39, and the mounting flange 38 is fastened to the support flange 31. At this time, the O-ring 34 in the seal groove 33 of the support bracket 31 comes into pressure contact with the end surface 38a of the mounting bracket 38 to seal around the connection portion between the intake passage 2 and the intake inlet 32.

  Next, in FIGS. 2 and 10, the mounting flange 38 includes a vent hole 41 that communicates the end surface 38 a outside the O-ring 34 with the inside of the control case 1 b, That is, a vent groove 42 on the end face 38a that is open to the atmosphere is provided, and the vent hole 41 and the vent groove 42 constitute a breathing path 43 that communicates with the atmosphere in the control case 1b.

  The ventilation groove 42 has a first groove 42a extending downward from the ventilation hole 41 on the end surface 38a, intersects with the lower end of the first groove 42a, and has one end opening on the outer surface of the mounting flange 38 and the other end. Is formed by a second groove 42b that extends beyond the intersection with the first groove 42a and that is close to the O-ring 34 and has a dead end. The second groove 42 b is formed in an arc shape so that it is aligned along the upper surface of the single bolt 35.

  The vent hole 41 includes a bottomed large-diameter hole 41a that opens to the end surface 38a, a bottom surface of the large-diameter hole 41a, and a small-diameter hole 41b that opens at both ends in the control case 1b. Steps 44 and 45 are provided between the bottom surface of the hole 41a and the groove bottom of the first groove 42a and between the groove bottoms of the first groove 42a and the second groove 42b, respectively.

  Further, the end face 38a is provided with a water release groove 47 whose one end opens above the breathing path 43 on the outer face of the mounting flange 38 and whose other end closes to the O-ring 34 and stops. The water escape groove 47 is disposed so as to be inclined so as to descend toward the outer surface of the mounting flange 38.

  As shown in FIG. 5, a drainage groove 48 that communicates the bottom of the control case 1 b to the outside below is provided on one of the joint surfaces of the case body 26 and the case cover 27.

  The operation of this embodiment will be described.

  For example, when a motorcycle is operated, when the rider rotates the accelerator grip in the acceleration or deceleration direction to accelerate or decelerate the motorcycle, the rotation angle is detected by an accelerator sensor, and the detection signal is transmitted to an electronic control unit (not shown). ) Is output. Based on this, the electronic control unit operates the electric motor 8 and drives the throttle valve 3 in the opening or closing direction via the reduction gear mechanism 9, so that the throttle body is controlled in accordance with the increase / decrease control of the opening degree of the throttle valve 3. By controlling the amount of intake air supplied to the engine through the intake passage 2 and the intake manifold M, the engine output can be increased or decreased. The opening degree of the throttle valve 3 that increases and decreases in this way is detected by the throttle sensor 16, and the detection signal is fed back to the electronic control unit. The operation of the electric motor 8 is controlled to correspond to the detection signal, and the opening degree of the throttle valve 3 can be automatically controlled to the opening degree corresponding to the rider's operation amount with respect to the accelerator grip. Can be obtained.

  By the way, in such an intake control device for an engine, the mounting flange 38 of the throttle body 1 has an O-ring 34 interposed between its end surface 38a and the support flange 31 of the intake manifold M joined thereto. A vent hole 41 that communicates the end surface 38a with the inside of the control case 1b and a vent groove 42 that opens the vent hole 41 to the outside of the mounting flange 38 are provided on the outside of the control case 1b. Since the breathing path 43 communicating with the atmosphere is configured, the inside of the control case 1b breathes through the breathing path 43 when the temperature changes due to the operation / stop of the throttle opening / closing control device A including the electric motor 8 to open / close the throttle. The controller A can be prevented from overheating and condensation. Moreover, since the respiratory path 43 including the vent hole 41 and the vent groove 42 constitutes a curved path, even if car wash water or rainwater enters the respiratory path 43, the momentum of the water is applied to the bent portion of the respiratory path 43. It is possible to prevent the water from entering the control case 1b. Moreover, the formation of the ventilation groove 42 on the end face 38a can be performed simultaneously with the formation of the mounting flange 38, and no special cutting process is required.

  The ventilation groove 42 intersects the first groove 42a extending downward from the ventilation hole 41 and the lower end of the first groove 42a, and one end opens to the outer surface of the mounting flange 38 and the other end is the first. Since it is composed of the second groove 42b extending beyond the intersection with the first groove 42a, a plurality of bent portions of the respiratory path 43 can be provided, and the momentum of the invading water from the outside is effectively attenuated. be able to. In particular, the second groove 42b is provided so that one end opens on the outer surface of the mounting flange 38 and the other end extends beyond the intersection with the first groove 42a. Even if the water is poured into the second groove 42b, the water can collide with the dead end portion of the second groove 42b beyond the intersection with the first groove 42a to effectively attenuate the momentum. Thus, the intrusion into the first groove 42a side can be suppressed, and the intrusion into the control case 1b can be prevented more reliably.

  Further, the vent hole 41 is composed of a bottomed large-diameter hole 41a that opens to the end surface 38a, and a small-diameter hole 41b that opens at both ends in the bottom surface of the large-diameter hole 41a and the control case 1b. Steps 44 and 45 are provided between the bottom surface of the large-diameter hole 41a and the bottom of the first groove 42a and between the bottom of the first groove 42a and the second groove 42b. The number of bent portions can be easily increased without specially extending the length, and therefore the momentum of the invading water from the outside can be effectively attenuated while the breathing path 43 is compactly configured.

  Furthermore, since the second groove 42b is inclined so as to descend toward the outer surface of the mounting flange 38, the water that has entered the second groove 42b and has been attenuated is directed toward the outer surface of the mounting flange 38. Naturally and smoothly flowing down, water can be reliably prevented from entering the breathing path 43.

  Further, since the second groove 42b is formed in an arc shape so as to be aligned along the upper surface of the bolt 35 that fastens the mounting flange 38 to the support flange 31, the second groove 42b and the end surface 38a of the mounting flange 38 are located below the bolt 35. When car wash water or rainwater enters the minute gap between the support flange 31 and the support flange 31 facing the bolt 35, the bolt 35 becomes a barrier, and the water enters the second groove 42b, and therefore enters the control case 1b. Infiltration can be prevented.

  In addition, the end face 38a of the mounting flange 38 is provided with a water release groove 47 whose one end is open to the outer surface of the mounting flange 38 above the breathing path 43 and whose other end is close to the O-ring 34. Therefore, in the upper part of the breathing path 43, car wash water and rainwater enter the minute gap between the end face 38 a of the mounting flange 38 and the support flange 31 facing the outer side of the O-ring 34, and enter the breathing path 43 side. Even if it flows down, the water is trapped in the water escape groove 47 and guided to the outside, so that it is possible to prevent the water from entering the breathing path 43 and hence into the control case 1b.

  In particular, the water escaping groove 47 is inclined so as to descend toward the outer surface of the mounting flange 38, so that the trapped water can flow naturally and smoothly toward the outer surface of the mounting flange 38. Intrusion of water into 43 can be reliably prevented.

  The present invention is not limited to the above embodiment, and various design changes can be made without departing from the scope of the invention. For example, the seal groove 33 for mounting the O-ring 34 can be provided on the end face 38 a side of the mounting flange 38.

1 is a side view of an intake control device for an engine according to an embodiment of the present invention. FIG. 2 is a sectional view taken along line 2-2 in FIG. 1. FIG. 3 is an enlarged sectional view taken along line 3-3 in FIG. 2. FIG. 4 is a sectional view taken along line 4-4 of FIG. FIG. 5 is a sectional view taken along line 5-5 of FIG. FIG. 5 is an enlarged vertical side view of a socket nut provided with a rotor of the throttle sensor in FIG. 4. FIG. 8 is a view taken in the direction of arrow 8 in FIG. 6. FIG. 8 is a cross-sectional view taken along line 8-8 in FIG. 6. FIG. 5 is a schematic diagram of a default mechanism in FIG. 4. FIG. 10 is an enlarged sectional view taken along line 10-10 in FIG. 2;

Explanation of symbols

A ... Throttle opening / closing control device 1 ... Throttle body 1a ... Intake cylinder 1b ... Control case 2 ... Intake passage 3 ... Throttle valve 31 ... Throttle body support (Support flange)
34... O-ring 35... Bolt 38... Mounting flange 38 a .. End face 41 of the mounting flange 41... Vent hole 41 a .. large diameter hole 41 b. 1st groove | channel 42b .. 2nd groove | channel 43 ... breathing path 44, 45 ... level | step difference 47 ... water escape groove | channel

Claims (6)

An intake cylinder (1a) that has an intake path (2) and supports a throttle valve (3) that opens and closes the intake path (2), and a control case that is connected to one side of the intake cylinder (1a) ( 1b) and a throttle opening / closing control device (A) accommodated in the control case (1b) for controlling the opening and closing of the throttle valve (3). The intake cylinder (1a) A mounting flange (38) having an end surface (38a) opened at the downstream end of the intake passage (2) is formed, and the mounting flange (38) is fastened to the throttle body support portion (31), and the mounting flange ( 38) An intake control device for an engine, in which an O-ring (34) surrounding the downstream end of the intake passage (2) is interposed between an end face (38a) of 38) and a throttle body support portion (31). ,
A vent hole (41) for communicating a portion of the end face (38a) covered with the throttle body support portion (31) outside the O-ring (34) into the control case (1b), and this vent hole ( 41) and the ventilation groove (42) on the end face (38a) that opens to the atmosphere constitute a breathing path (43) that communicates with the atmosphere in the control case (1b). On the upper side, the end face (38a) is provided with a water release groove (47) whose one end is open to the outer face of the mounting flange (38) and whose other end is close to the O-ring (34). The breathing structure of the control case in the engine intake control system. In the breathing structure of the control case in the engine intake control device according to claim 1,
The ventilation groove (42) on the end surface (38a) intersects the first groove (42a) extending downward from the ventilation hole (41) and the lower end of the first groove (42a), and one end is attached to the attachment surface. In an intake control device for an engine, characterized in that it is formed by a second groove (42b) that opens to the outer surface of the flange (38) and has the other end extending beyond the intersection with the first groove (42a). The breathing structure of the control case. In the breathing structure of the control case in the intake control device for an engine according to claim 2,
The vent hole (41) has a bottomed large-diameter hole (41a) that opens to the end face (38a), a bottom diameter of the large-diameter hole (41a), and a small diameter that opens both ends in the control case (1b). A hole (41b) between the bottom surface of the large-diameter hole (41a) and the groove bottom of the first groove (42a), and between the first groove (42a) and the second groove (42b). A breathing structure of a control case in an intake control device for an engine, wherein steps (44, 45) are provided between the groove bottoms. In the breathing structure of the control case in the engine intake control device according to claim 1,
A breathing structure of a control case in an intake control device of an engine, characterized in that the water escape groove (47) is inclined so as to be lowered toward the outer surface of the mounting flange (38). In the breathing structure of the control case in the intake control device for an engine according to claim 2,
A breathing structure of a control case in an intake control device for an engine, wherein the second groove (42b) is inclined so that the second groove (42b) is lowered toward the outer surface of the mounting flange (38). In the breathing structure of the control case in the intake control device for an engine according to claim 2,
The mounting flange (38) is fastened to the throttle body support (31) by a bolt (35) arranged outside the O-ring (34), and the second groove (42b) is connected to the bolt (35). The breathing structure of the control case in the intake control device of the engine, characterized in that it is formed in an arc shape so as to be lined up along the upper surface.

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