JP2010223047A - Idle adjusting device for engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the adhesion of a foreign matter to a metering portion, and to temporarily stabilize an adjusted idle intake air volume for a long period of time by easily catching the minute foreign matter entering a bypass. <P>SOLUTION: A throttle body 1 is formed with a screw hole 38, a valve hole 33 continued to the inner end of the screw hole, and a metering hole 34 formed at the inner surface of the valve hole. The bypass 30 is formed in such a manner that the valve hole 33 communicates with the upstream of an intake air passage 7 and the metering hole 34 communicates with the downstream of the intake air passage 7. An idle adjusting valve 31 is composed of a screw shaft 42 screwed in the screw hole 38 and an adjusting valve shaft 43 provided adjacently to the end of the screw shaft and rotatably and slidably fitted into the valve hole 33. The adjusting valve shaft 43 is formed with a dead-end hole 48 formed at the end surface of the adjusting valve shaft, a metering groove 49 surrounding the periphery of the adjusting valve shaft 43 and communicating with the metering hole 34, and a plurality of through holes 50 allowing the dead-end hole 48 to communicate with the metering groove 49. The dead end of the dead-end hole 48 beyond the through holes 50 is made to serve as a foreign matter reservoir 51. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  In the present invention, a throttle body having an intake passage that is opened and closed by a throttle valve is provided with a bypass that bypasses the throttle valve and communicates with the intake passage, and the idle intake amount of the engine flowing through the bypass is adjusted by opening and closing the bypass. The present invention relates to an improvement of an engine idle adjusting device in which an idle adjusting valve is screwed onto a throttle body.

Such an idle adjustment device for an engine is already known as disclosed in Patent Document 1.
JP 2006-307730 A

  In a conventional engine idle adjustment device, the end face of the valve shaft formed at the tip of the idle adjustment valve faces the opening of the measurement hole that constitutes a part of the bypass, and the adjustment of the valve shaft is adjusted by moving the valve shaft forward and backward. The amount of idle intake of the engine has been adjusted by adjusting the opening, but in such cases, fine dust that has passed through the air cleaner provided at the inlet of the intake passage and foreign matter such as soot in blown-back gas from the engine It may adhere to the metering part of the valve shaft or the metering hole, and the adjustment of the idle intake amount may be upset. In this case, the idle intake amount needs to be readjusted by the idle adjustment valve.

  The present invention has been made in view of such circumstances, and easily captures fine foreign matter that has entered the bypass, prevents the foreign matter from adhering to the measuring section, and increases the idle intake amount once adjusted. An object of the present invention is to provide an engine idle adjustment device that can be stabilized for a period of time.

  In order to achieve the above object, the present invention provides a throttle body having an intake passage that is opened and closed by a throttle valve with a bypass that bypasses the throttle valve and communicates with the intake passage. In an engine idle adjustment device in which an idle adjustment valve for adjusting an idle intake amount of a flowing engine is screwed to a throttle body, a screw hole is formed in the throttle body, and a valve hole coaxially connected to an inner end of the screw hole. And a metering hole that opens on the inner surface of the valve hole, and one of the valve hole and the metering hole communicates with the intake passage upstream of the throttle valve and the other communicates with the intake passage downstream of the throttle valve. A bypass is configured, and the idle adjustment valve is screwed into the screw hole and is connected to the tip of the screw shaft so as to be rotatable and slidable in the valve hole. The valve shaft includes a dead end hole that opens at an end surface thereof and communicates with the valve hole, an annular measurement groove that surrounds the outer periphery of the valve shaft and communicates with the measurement hole, A plurality of through holes communicating with the measuring groove in the axial direction intermediate portion of the dead end hole are provided, and the communication width of the measuring groove with the measuring hole can be adjusted by adjusting the axial movement of the valve shaft. The first feature is that the dead end portion of the dead end hole behind the through hole is a foreign matter reservoir.

  In addition to the first feature of the present invention, the second feature is that the through hole is displaced from the metering hole along the axial direction of the valve shaft at any adjustment position of the valve shaft. To do.

  Furthermore, in addition to the first or second feature, the present invention has a third feature that four through holes are arranged at equal intervals along the circumferential direction of the valve shaft.

  According to the first feature of the present invention, when the foreign matter flows into the valve hole together with the idle intake, the idle intake is bent at a right angle from the dead end hole to the through hole and moves to the annular measuring groove. Thus, the foreign matter that has entered the dead-end hole travels straight due to the inertia of the flow, is captured in the foreign-material reservoir at the back of the dead-end hole, and is separated from the idle intake air. As a result, it is possible to prevent foreign matter from adhering to the measuring groove and the measuring portion of the measuring hole, and the idle intake amount once adjusted by the idle adjusting valve can be stabilized for a long period of time.

  According to the second feature of the present invention, even if foreign matter moves from the through hole to the measuring groove together with idle intake, the through hole and the measuring hole are always displaced from each other along the axial direction of the valve shaft. Therefore, idle intake air that has moved from the through hole to the measuring groove immediately bends the path at a right angle toward the measuring hole, whereas foreign matter that has passed through the through hole collides with the inner peripheral surface of the valve hole due to inertia. Then it falls to the bottom of the valve hole and is separated from idle intake. As a result, it is possible to further prevent foreign matter from adhering to the measuring portion of the measuring groove and the measuring hole.

  According to the third feature of the present invention, since four through holes are arranged at equal intervals along the circumferential direction of the valve shaft, the change in the idle intake amount with respect to the change in the rotation angle of the idle adjustment valve becomes smooth. , Idle intake volume can be adjusted easily and accurately. Moreover, four through holes can be formed by simple hole processing from two directions, and the workability is good.

1 is a longitudinal side view of a motorcycle engine intake control apparatus according to an embodiment of the present invention (a cross-sectional view taken along line 1-1 of FIG. 3). FIG. 2 is a view taken along arrow 2-2 in FIG. 1. FIG. 3 is a sectional view taken along line 3-3 in FIG. 1. FIG. 4 is a cross-sectional view taken along line 4-4 of FIG. FIG. 5 is a sectional view taken along line 5-5 of FIG. FIG. 6 is a sectional view taken along line 6-6 of FIG. FIG. 7 is an enlarged sectional view taken along line 7-7 in FIG. 2 (idle intake air amount minimum adjustment state). FIG. 8 is an operation explanatory diagram corresponding to FIG. 7 (idle intake air amount maximum adjustment state). FIG. 9 is a sectional view taken along line 9-9 in FIG. 3. The diagram which shows the relationship between the rotation angle of an idle adjustment valve, and idle intake air quantity.

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

  First, in FIGS. 1 to 4, the throttle body 1 is made of a die casting made of a light alloy, and includes a cylindrical portion 1a and a flange portion 1b projecting from one end of the cylindrical portion 1a to the outer periphery. Is done. The flange portion 1b has a substantially square shape when viewed from the front (see FIG. 3), and a pair of upper and lower first and second fastening bosses 2 and 2 'are formed at one corner of the flange portion 1b. The second fastening bosses 2 and 2 'are coupled to the joint flange portion of the intake pipe 5 of the engine by a pair of fastening bolts 3 and 3. An inlet tube 6 connected to the air cleaner is fitted and connected to the outer periphery of the cylindrical portion 1a.

  The throttle body 1 has a cylindrical intake passage 7 that communicates between the inlet tube 6 and the intake pipe 5, and the intake passage 7 is valved with respect to the outer center of the cylinder portion 1 a of the throttle body 1. It is formed eccentrically downward below the axis 8a. A valve shaft 8 a of a butterfly throttle valve 8 that opens and closes the intake passage 7 is rotatably supported by a pair of first and second bearing bosses 9 and 9 ′ formed on the throttle body 1. The first and second bearing bosses 9 and 9 'are formed integrally with the cylindrical portion 1a at one half circumference and the flange portion 1b at the other half circumference. At that time, it is desirable that the first and second bearing bosses 9 and 9 'are arranged so that one side surface thereof is substantially flush with the end surface of the flange portion 1b as shown in the drawing.

  Thus, by forming the first and second bearing bosses 9 and 9 ′ from the cylindrical portion 1 a to the flange portion 1 b, the throttle valve 8 can be disposed close to the downstream end of the intake passage 7. The size of the throttle body 1, particularly the axial dimension of the throttle body 1, can be greatly reduced.

  2 to 4, a throttle drum 10 is fixed to one end portion of the valve shaft 8a, and an operation wire 11 for opening and closing the throttle valve 8 is attached to the throttle drum 10 (see FIG. 4). Is connected.

  The upper first fastening boss 2 is arranged so that a part thereof overlaps with the cylindrical body 1a in a plan view, and a stay boss 15 is integrally provided outside the first fastening boss 2. A guide tube stay 13 that supports the end portion of the guide tube 12 of the operation wire 11 is fixed to the stay boss 15 with a screw 16 on the end surface of the stay boss 15 on the cylindrical portion 1a side. At that time, a positioning pin 18 protruding from the end surface of the stay boss 15 on the side of the cylindrical portion 1a is fitted into a positioning hole 17 which is formed in the guide tube stay 13 and is adjacent to the lower side of the screw 16. Accordingly, the rotation of the guide tube stay 13 around the screw 16 is prevented. As a result, the guide tube stay 13 can be fixed to the stay boss 15 with a single screw 16. The distal end portion of the positioning pin 18 passes through the positioning hole 17 and protrudes from the outer surface of the guide tube stay 13, and a stopper arm 10 a that abuts against the distal end portion and regulates the fully open position of the throttle valve 8 serves as a throttle drum. 10 integrally formed. That is, since the positioning pin 18 also serves as a stopper pin that restricts the fully open position of the throttle valve 8, a dedicated stopper pin is not required, and the structure can be simplified.

  Further, a full-closed stopper boss 20 is integrally formed on the flange portion 1b on the opposite side of the stay boss 15 with the first bearing boss 9 interposed therebetween. The full-closed stopper boss 20 receives the stopper arm 10a and receives a throttle. A fully closed stopper bolt 21 for restricting the fully closed position of the valve 8 is screwed.

  In the above, the holes of the first and second fastening bosses 2, 2 ′, the stay boss 15, the positioning pin 18, and the fully closed stopper boss 20 are arranged in parallel with the intake passage 7. By doing so, it is possible to perform mold forming and drilling for the intake passage 7, the first and second fastening bosses 2, 2 ′, the stay boss 15, the positioning pin 18, and the fully closed stopper boss 20 all at once. Good properties.

  A space 22 is formed around the first bearing boss 9 to separate the stay boss 15 and the fully-closed stopper boss 20. The space 22 is used to urge the throttle drum 10 in the closing direction of the throttle valve 8. A torsion coil type return spring 23 is disposed on the outer periphery of the bearing boss 9.

  Thus, the stay boss 15, the first bearing boss 9, the return spring 23, and the fully closed stopper boss 20 can be aligned on one side of the flange portion 1b, which can contribute to the compactness of the throttle body 1. At this time, in particular, the stay boss 15 from one side of the flange portion 1b is integrally provided on the outside of the first fastening boss 2 that is arranged so as to partially overlap the cylindrical portion 1a in plan view. The projection length of the fully-closed stopper boss 20 aligned with the stay boss 15 from the flange portion 1b can also be kept short, thereby further reducing the throttle body 1 in size. Can contribute.

  As shown in FIGS. 1 and 3, a casing 25 of a throttle sensor 25 that detects the opening of the throttle valve 8 is fitted to the outer periphery of the second bearing boss 9 ′. On the other hand, a sensor support boss 27 aligned with the second fastening boss 2 ′ is formed integrally with the flange portion 1 b so as to sandwich the second bearing boss 9, and a bolt 28 for fastening the casing 25 to the sensor support boss 27. It is concluded by. The sensor support boss 27 is disposed in parallel with the second bearing boss 9. According to such an arrangement, the second bearing boss 9 and the sensor support boss 27 can be molded and drilled at once, and the workability is good.

  Thus, the second fastening boss 2 ', the second bearing boss 9', and the sensor support boss 27 can be aligned with the other side of the flange portion 1b, and the stay boss 15, the first bearing boss 9, the return spring 23, and the fully closed Combined with the arrangement of the stopper boss 20 on one side of the flange portion 1b, the overall throttle body 1 can be greatly reduced in size.

  2, 3, and 5 to 8, a bypass 30 that bypasses the throttle valve 8 and communicates with the intake passage 7 is formed in the throttle body 1. The bypass 30 is provided to supply idling intake air (hereinafter referred to as idle intake air) to the engine, and an idle adjustment valve 31 for adjusting the idle intake air amount is screwed to the throttle body 1. . The bypass 30 and the idle adjustment valve 31 will be described in detail below.

  The bypass 30 includes a concave groove 32 (see FIGS. 2, 5, and 6) formed on the upper surface of the intake passage 7 in a range from the upstream end of the throttle body 1 to the front of the throttle valve 8, and the concave groove 32. Cylinder-shaped valve hole 33 (see FIG. 7) that extends in a direction that bends at right angles from the valve hole 33, a measurement hole 34 that extends from the middle of the valve hole 33 toward the downstream end of the throttle body 1, and the measurement hole 34 that serves as an intake passage. 7 is formed with a notch 35 (see FIG. 3) formed on the end surface of the flange portion 1b of the throttle body 1 joined to the intake pipe 5 so as to communicate with the downstream end portion.

  As described above, the concave groove 32 is formed in the upper portion of the cylinder portion 1a by decentering the intake passage 7 downward perpendicular to the valve shaft 8a with respect to the outer shape center of the cylinder portion 1a of the throttle body 1. The thick portion 36 is formed. As a result, the flow passage area of the concave groove 32 can be sufficiently obtained without reducing the strength of the throttle body 1, and the other part of the bypass 30 following the concave groove 32 is obstructed by the valve shaft 8a. It can form easily, without.

  On the outer end side of the valve hole 33, a screw hole 38 and a guide hole 39 that gradually increase in diameter are connected in a coaxial manner, and the guide hole 39 opens on the outer surface of the throttle body 1. The guide hole 39, the screw hole 38, and the valve hole 33 are formed in parallel with the second bearing boss 9 'in the same manner as the sensor support boss 27. By doing so, it is possible to perform mold forming and drilling for each of the holes, the sensor support boss 27 and the second bearing boss 9 'all at once, and the workability is good.

  As shown in FIGS. 1, 5 and 6, the concave groove 32 has a dead end portion 32a on the downstream side thereof, and the valve hole 33 is bent at a right angle from the front of the dead end portion 32a. It is arrange | positioned so that it may extend. Further, the opening 33a of the valve hole 33 to the concave groove 32 is narrowed, and the opening 33a opens to a step 32c raised by one step from the inner side surface 32b of the concave groove 32, and The opening 33a is arranged away from the periphery of the step 32c.

  The step portion 33c is formed to be continuous with the ceiling surface of the groove 32 and the dead end portion 32a. According to this, at the time of mold forming of the throttle body 1, it is possible to remove the mold from the intake passage 7 and the recessed groove 32 without being interfered by the stepped portion 32 c.

  On the other hand, the idle adjustment valve 31 is configured by integrally connecting a main shaft 41, a screw shaft 42, and an adjustment valve shaft 43 in a coaxial manner so that the diameter gradually decreases, and the main shaft 41 has a huge head with a tool groove 44. 41a is provided at the outer end, and an O-ring 45 is mounted on the outer periphery. The adjusting valve shaft 43 is fitted in the valve hole 33 so as to be rotatable and slidable, the screw shaft 42 is screwed into the screw hole 38, and the main shaft 41 is inserted into the guide hole 39 through the O-ring 45. A coil spring 46 for preventing rotation of the idle adjustment valve 31 is contracted between the outer surface of the throttle body 1 and the enormous head 41a.

  The adjustment valve shaft 43 has a dead end hole 48 that opens at its end surface and communicates with the valve hole 33, an annular measurement groove 49 that surrounds the outer periphery of the adjustment valve shaft 43 and communicates with the measurement hole 34, and a dead end hole 48. Are provided with a plurality of through holes 50, 50... Communicating with the measuring groove 49. The groove width of the measuring groove 49 is set sufficiently longer than the inner diameter of the measuring hole 34. Further, the dead end portion of the dead end hole 48 beyond the through holes 50, 50.

  The measuring hole 34 and the through holes 50, 50... Are always arranged so as to be offset from each other along the axial direction of the adjusting valve shaft 43 at any adjustment position of the adjusting valve shaft 43.

  As shown in FIG. 1, the number of the plurality of through holes 50, 50... Is preferably four that are arranged at equal intervals in the circumferential direction of the adjustment valve shaft 43. One or a plurality of annular grooves 52 (see FIG. 6) constituting a labyrinth seal are formed on the outer peripheral surface of the tip of the adjustment valve shaft 43.

  Thus, when the engine with the throttle valve 8 fully closed is idling, the air flowing into the intake passage 7 is bypass 30, that is, the concave groove 32, the valve hole 33, the dead end hole 48, the plurality of through holes 50, 50,. After passing through the measuring groove 49 and the cutout portion 35 in order, it moves to the downstream side of the intake passage 7 and is further supplied to the engine as idle intake through the intake pipe 5. The amount of idle intake can be adjusted by adjusting the communication width w of the measurement groove 49 with the measurement hole 34 by adjusting the advancement / retraction of the adjustment adjustment valve shaft 43 by screwing the screw in and adjusting the idle adjustment valve 31. That is, as shown in FIG. 7, if the communication width w is narrowed, the idle intake amount can be reduced, and if the communication width w is widened as shown in FIG. 8, the idle intake amount can be increased.

  When adjusting the idle intake air amount, even if the offset amount along the axial direction of the adjustment valve shaft 43 between the through holes 50, 50... When the positions of the holes 50, 50... Change, the distance between the measuring hole 34 and the nearest through hole 50 changes, so that the idle intake air amount slightly changes. Therefore, the change in the idle intake amount with respect to the rotation angle of the idle adjustment valve 31 is obtained when the two through holes 50 are arranged at equal intervals in the circumferential direction of the adjustment valve shaft 43 (A), and the four through holes 50 are provided. When the case (B) where they are arranged at equal intervals was actually examined, the result as shown in FIG. 10 was obtained. As is clear from the above, in the case of (B), the idle intake amount changes more smoothly, and the idle intake amount can be adjusted easily and accurately. Moreover, in the case of (B), since the four through holes 50 can be formed simply by drilling the adjusting valve shaft 43 from two directions, the workability is good. Therefore, it is preferable to adopt (B).

  By the way, water droplets due to condensation or the like may adhere to the inner surface of the concave groove 32, and the water droplet may flow into the concave groove 32 together with the idle intake air. In this case, the valve hole 33 communicating with the concave groove 32 is disposed in a direction that is bent at a substantially right angle from the front of the dead end portion 32a of the concave groove 32, and the opening 33a of the valve hole 33 to the concave groove 32 is Since the opening 33a is disposed away from the peripheral edge of the step portion 33a, the inner surface 32b of the groove 32 is formed on the step portion 32c. The flowing water droplets flow around the step portion 32c as shown by the arrow a in FIG. 5 and the arrow b in FIG. 6 due to the inertia of the flow, thereby avoiding the opening 33a and preventing the water droplet from entering the valve hole 33. Can do.

  If foreign matter such as water droplets or fine dust flows into the valve hole 33 together with the idle intake, the idle intake bends the path from the dead end hole 48 to the through holes 50, 50. In contrast to the movement to the measuring groove 49, the foreign matter that has entered the dead end hole 48 advances straight due to the inertia of the flow, is captured by the foreign matter reservoir 51 behind the dead end hole 48, and is separated from the idle intake air.

  Furthermore, even if there is a foreign object that has moved from the through holes 50, 50... To the measuring groove 49 along with idle intake, the through holes 50, 50... And the measuring hole 34 are at any adjustment position of the adjusting valve shaft 43. However, since they are always offset from each other along the axial direction of the adjusting valve shaft 43, the idle intake air that has moved from the through holes 50, 50... To the measuring groove 49 immediately bends the course at a right angle toward the measuring hole 34. On the other hand, the foreign matter that has passed through the through holes 50, 50... Collides with the inner peripheral surface of the valve hole 33 due to inertia, falls to the lower part of the valve hole 33, and is separated from the idle intake air.

  Thus, foreign matter can be prevented from adhering to the measuring portion of the measuring groove 49 and the measuring hole 34, so that the idle intake amount once adjusted by the idle adjusting valve 31 can be stabilized for a long period of time.

  When the throttle valve 8 is opened to accelerate the engine, the intake air flowing into the intake passage 7 goes straight through the intake passage 7 while being controlled in flow rate by the opening degree of the throttle valve 8 and is sucked into the engine. At this time, since the inlet of the bypass 30 is a concave groove 32 recessed from the inner surface of the intake passage 7, the flow passage area of the intake passage 7 is not reduced, and the flow of intake air going straight through the intake passage 7 is hindered. Absent. This can reduce the intake resistance of the engine and contribute to improving its output.

  Even when such an engine is loaded, even if there are water droplets flowing along the inner surface 32b of the concave groove 32, the opening portion 33a of the valve hole 33 is formed by the step portion 32c as in the idling described above. Water droplets can be prevented from entering.

  3 and FIG. 7 again, the notch 35 having a notch shape serving as the downstream end of the bypass 30 is formed obliquely above the intake passage 7 on the end face of the flange portion 1b facing the intake pipe 5. A water-drop shaped seal groove 53 that opens and surrounds the notch 35 and the intake passage 7 is formed on the end surface of the flange portion 1b. The seal groove 53 includes first and second fastening bosses 2 of the flange portion 1b. , 2 ′ are fastened to the intake pipe 5 by the fastening bolts 3, 3, an O-ring 54 that is in close contact with the end surface of the intake pipe 5 is attached. At that time, seating surfaces 2a and 2a 'slightly raised from the surface of the flange portion 1b where the seal groove 53 is formed are formed on the fastening bosses 2 and 2'. The notch 35 is disposed on one side of a straight line 55 that crosses the intake passage 7 and connects the centers of the first and second fastening bosses 2 and 2 ', and on the other side, the flange portion 1b. An arc-shaped contact seat 56 (see FIGS. 3 and 9) slightly raised from the seal groove 53 forming surface is formed along a part of the outer edge of the seal groove 53. The abutment seat 56 and the seat surfaces 2a and 2a 'are finished to the same plane after the throttle body 1 is cast.

  Thus, at the time of the fastening, the three locations of the seat surfaces 2a, 2a 'and the abutment seat 56 abut against the end surface of the intake pipe 5 to accurately regulate the amount of compressive deformation of the O-ring 54, and the seal The function can be kept for a long time. In addition, when finishing the contact surface of the flange portion 1b with the intake pipe 5 into the same plane, the three seat surfaces 2a, 2a 'and the contact seat 56 of the first and second fastening bosses 2, 2' are provided. It is only necessary to finish the workpiece, improving the machining efficiency and extending the life of the machining tool. Further, the notched portion 35 and the abutment seat 56 are arranged on opposite sides of the straight line 55 connecting the centers of the two fastening bosses 2 and 2 ', so that a portion having a complicated shape is dispersed. , It is possible to improve the hot water resistance during die casting.

The present invention is not limited to the above embodiments, and various design changes can be made without departing from the scope of the invention. For example, the seal groove 53 can be formed on the end surface of the intake pipe 5 facing the flange portion 1b. In the above embodiment, the present invention is applied to the horizontal type throttle body 1 with the intake passage 7 horizontal, but it can also be applied to a vertical type throttle body with the intake passage 7 oriented in the vertical direction. In the bypass 30, the valve hole 33 can be communicated with the downstream portion of the intake passage 7 and the measurement hole 34 can be communicated with the upstream portion of the intake passage 7, contrary to the above embodiment.

w ... Communication width 1 ... Throttle body 7 ... Intake passage 8 ... Throttle valve 30 ... Bypass 31 ... Idle adjustment valve 33 ...・ Valve hole 34 ・ ・ ・ ・ Measuring hole 38 ・ ・ ・ ・ Screw hole 42 ・ ・ ・ ・ Screw shaft 43 ・ ・ ・ ・ Adjusting valve shaft 48 ・ ・ ・ ・ Dead stop hole 49 ・ ・ ・ ・ Measuring groove 50・ Through hole 51 ・ ・ ・ ・ Foreign matter accumulation

Claims (3)

A throttle body (1) having an intake passage (7) that is opened and closed by a throttle valve (8) is provided with a bypass (30) that bypasses the throttle valve (8) and communicates with the intake passage (7). In the engine idle adjustment device, the idle adjustment valve (31) for adjusting the idle intake amount of the engine flowing through the bypass (30) by opening and closing 30) is screwed to the throttle body (1).
The throttle body (1) has a screw hole (38), a valve hole (33) coaxially connected to the inner end of the screw hole (38), and a metering hole (opening on the inner surface of the valve hole (33)). 34), and one of the valve hole (33) and the metering hole (34) is provided on the intake passage (7) upstream of the throttle valve (8), and the other is provided on the intake passage (7) downstream of the throttle valve (8). 7) are connected to each other to form a bypass (30), and the idle adjustment valve (31) is connected to the screw shaft (42) screwed into the screw hole (38) and the tip of the screw shaft (42). And an adjusting valve shaft (43) fitted in the valve hole (33) so as to be rotatable and slidable. The adjusting valve shaft (43) has an opening at the end surface thereof, and the valve hole A dead end hole (48) communicating with (33) and the measuring hole surrounding the outer periphery of the adjusting valve shaft (43) 34) provided with an annular measuring groove (49) communicating with the measuring groove (49) and a plurality of through holes (50) communicating with the measuring groove (49) at an axially intermediate portion of the dead end hole (48). The communication width (w) of the measuring groove (49) with the measuring hole (34) can be adjusted by adjusting the forward and backward movement in the axial direction of (43), and the through hole (50) of the dead end hole (48) can be adjusted. ) An idle adjustment device for an engine, characterized in that the dead end portion in the back is a foreign matter reservoir (51). The engine idle adjustment device according to claim 1,
In any adjustment position of the adjustment valve shaft (43), the through hole (50) is displaced from the metering hole (34) along the axial direction of the adjustment valve shaft (43). Idle adjuster. The engine idle adjustment device according to claim 1 or 2,
An idle adjusting device for an engine, wherein four through holes (50) are arranged at equal intervals along a circumferential direction of the adjusting valve shaft (43).

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