JP2005291023A - Muffler - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce engine suction noise in a low revolution speed zone and suppress increase of suction resistance in a high revolution speed zone without requiring electrical control. <P>SOLUTION: This muffler is provided with a throttle valve 50 for muffling provided in an intake pipe 40 of an engine and a second cable 60 mechanically connecting the throttle valve 50 for muffling and an accelerator lever for adjusting engine revolution speed. The throttle valve 50 for muffling is connected to the accelerator lever via the second cable 60 to reduce throttling amount by operation of the accelerator lever for increasing engine revolution speed and to increase throttling amount by operation of the accelerator lever for decreasing engine revolution speed. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a silencer for reducing noise associated with engine intake.

2. Description of the Related Art Conventionally, as disclosed in Patent Document 1 below, for example, a silencer for reducing engine intake noise radiated from an intake port of an engine (internal combustion engine) is known. In the silencer disclosed in this document, a valve body made of a disk with an opening is provided in an intake pipe of an engine, and intake noise is reduced by the valve body. That is, when the engine speed is low, a low-frequency booming noise is generated in the cab, so when the engine speed is equal to or lower than a predetermined value, the reflection valve is rotated so as to be orthogonal to the flow path direction. By moving it, the intake noise radiated from the intake port is reduced. When the engine speed exceeds a predetermined value, the reflection valve rotates so as to face in the direction parallel to the flow path direction, thereby opening the intake pipe fully open and increasing the intake resistance in the high engine rotation range. I try not to.
JP 2002-48020 A

  Although what is disclosed in Patent Document 1 has an advantage of reducing low-frequency intake noise generated in a low rotation region, not only a device for detecting the engine speed is required, but also a valve based on this detection value. Control means for controlling the body is also required, which results in a significant cost increase to reduce intake noise. Moreover, there is a risk of malfunction or malfunction due to electrical control.

  Accordingly, the present invention has been made in view of the above points, and an object of the present invention is to reduce intake noise in a low rotation region and increase suction resistance in a high rotation region without requiring electrical control. It is to suppress.

  In order to achieve the above-mentioned object, the present invention presupposes a silencer for reducing noise caused by intake of an engine, and a silencer throttle valve provided in the intake pipe of the engine, and the rotational speed of the engine. An accelerator lever for adjusting and a connecting member for mechanically connecting the silencer throttle valve, the silencer throttle valve reduces the throttle amount by operating the accelerator lever to increase the engine speed, The throttle lever is connected to the accelerator lever via the connecting member so as to increase the throttle amount by operating the accelerator lever that lowers the engine speed.

  In this invention, since the silencer throttle valve is mechanically connected to the accelerator lever via the connecting member, when the accelerator lever is operated, the silencer throttle valve moves accordingly, and the throttle amount in the intake pipe changes. . At this time, when the accelerator lever is operated to increase the engine speed, the silencer throttle valve moves to reduce the throttle amount via the connecting member, while when the accelerator lever is operated to decrease the engine speed, The throttle valve moves through the connecting member so as to increase the throttle amount. In other words, when the engine speed is low, the muffled noise is silenced by narrowing the intake pipe, while operating the accelerator lever to increase the engine speed increases the air intake amount accordingly. Since the throttle amount of the throttle valve for use is reduced, the suction resistance is reduced.

  The connecting member may include an outer cable held by the engine and an inner cable that is inserted in the outer cable so as to be movable forward and backward and connects the accelerator lever and the silencer throttle valve.

  The silencer throttle valve includes an annular main body portion having substantially the same inner diameter as the intake pipe, a rotary lever portion having a rotary shaft penetrating the main body portion in a direction perpendicular to the axis of the main body portion, A valve body that is disposed inside the main body portion, rotates around the rotation axis of the rotation lever portion, and changes the flow path area depending on the rotation angle can be provided.

  In this case, the valve body is formed in a flat plate shape having an outer diameter corresponding to the inner diameter of the main body portion, and an opening portion having a predetermined area ratio with respect to the flow passage area of the intake pipe is provided at the center portion thereof. It is good also as composition which has.

  As described above, according to the silencer according to the present invention, the silencer throttle valve moves so as to change the throttle amount in the intake pipe via the connecting member in accordance with the operation of the accelerator lever. It is possible to suppress an increase in intake resistance in the high rotation range while reducing intake noise in the low rotation range. Further, since no control means is required, intake noise can be reduced at a low cost. Further, since the control means does not fail or malfunction, the intake noise can be reliably reduced.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings.

  FIG. 1 partially shows a work machine to which a silencer according to this embodiment is applied. This working machine is configured as a mini excavator, for example, and FIG.

  The upper revolving structure 10 has an operation space 12 at the center thereof, and a machine room 16 in which the engine 14 (see FIG. 2) and the like are housed in the lower part. The driving space 12 is provided with a seat 18 on which a driver sits, a control box (not shown), an accelerator lever 20 and the like, and a seat stand 22 (see FIG. 2). The seat 18 is disposed at the substantially central part of the body, and the control box and the accelerator lever 20 are disposed on the right side of the body of the seat 18.

  As shown in FIG. 2, the accelerator lever 20 includes a lever main body 24 having an upper end portion formed as a grip portion, and a rotation support shaft 26 provided on the lever main body 24 and extending in the body width direction. . The rotation support shaft 26 is inserted into an insertion hole 28a of a bracket 28 attached to the seat stand 22, whereby the accelerator lever 20 is rotatably supported in the front-rear direction. FIG. 2 shows each member disassembled for convenience.

  The engine 14 is horizontally placed below the seat stand 22 as shown in the figure, and the engine 14 includes a governor lever 30 for operating a governor (not shown) at the rear thereof. The engine 14 can increase the engine speed by rotating the governor lever 30 around the base in one direction, and can decrease the engine speed by rotating in the other direction.

  A first connection portion 32 is provided at a lower end portion of the lever main body 24 of the accelerator lever 20, and the first connection portion 32 is connected to the governor lever 30 via a first cable 34. The first cable 34 has a double structure, and the outer cable 34 a is held by the engine 14 via a bracket 36. Both ends of the inner cable 34b of the first cable 34 protrude from the outer cable 34a and are inserted into the outer cable 34a so as to be relatively movable in the axial direction. One end of the inner cable 34 b is coupled to the first connection portion 32 of the accelerator lever 20, and the other end is coupled to the governor lever 30. Then, by rotating the accelerator lever 20 in the front-rear direction, the inner cable 34b moves relative to the outer cable 34a in the axial direction, and the governor lever 30 rotates around its base.

  As shown in FIG. 3, an intake pipe 40 is disposed on the upper portion of the engine 14. The intake pipe 40 is divided into a first intake pipe 42 and a second intake pipe 44, and an air cleaner 46 is provided between the first intake pipe 42 and the second intake pipe 44. An intake port 47 for taking in outside air is opened in the first intake pipe 42, and the first intake pipe 42 guides outside air to the air cleaner 46. The second intake pipe 44 guides the air filtered by the air cleaner 46 to the intake port of the engine 14.

  The second intake pipe 44 is provided with a silencer throttle valve 50 for reducing noise accompanying intake air of the engine 14. As shown in FIG. 4, the silencer throttle valve 50 includes an annular main body 52 having an inner diameter that is substantially the same as the inner diameter of the second intake pipe 44, and a rotary lever that is rotatably attached to the main body 52. A portion 54 and a disc-like valve body 56 disposed inside the main body portion 52 are provided, and are configured by so-called butterfly valves.

  The rotation lever portion 54 has a rotation shaft 58 that penetrates the main body portion 52 in a direction orthogonal to the air flow direction, and rotates around the rotation shaft 58.

  As shown in FIGS. 2 and 3, the turning lever portion 54 is connected to the accelerator lever 20 via a second cable 60 as an example of a connecting member. The second cable 60 has a double structure, and the outer cable 60 a is held by the engine 14 via a bracket 62. Both ends of the inner cable 60b of the second cable 60 protrude from the outer cable 60a and are inserted into the outer cable 60a so as to be relatively movable in the axial direction. A second connection portion 64 is provided at a lower end portion of the lever main body 24 of the accelerator lever 20, and one end portion of the inner cable 60 b is fixed to the second connection portion 64 of the accelerator lever 20. On the other hand, the other end portion of the inner cable 60 b is coupled to the rotating lever portion 54 via the connection member 66. The connection between the connecting member 66 and the rotation lever portion 54 is a pin connection, and the rotation lever portion 54 rotates as the inner cable 60b moves in the axial direction indicated by an arrow in FIG. ing. When the accelerator lever 20 is rotated in the front-rear direction, the inner cable 60b moves relative to the outer cable 60a in the axial direction, and the rotation lever portion 54 is rotated around the rotation shaft 58. ing.

  As shown in FIG. 4, the valve body 56 of the silencer throttle valve 50 has an outer diameter corresponding to the inner diameter of the main body 52, and an opening 56 a is formed in the valve body 56. The valve body 56 is provided on a rotation shaft 58 of the rotation lever portion 54, and rotates around the rotation shaft 58 together with the rotation lever portion 54. The valve body 56 is set to rotate between a direction orthogonal to the air flow direction and a direction parallel to the air flow direction, and the flow path area is changed by the rotation angle. Can be done. The muffling throttle valve 50 makes the valve body 56 orthogonal to the air flow direction during idling in order to increase the throttle amount at a low engine speed that causes a booming noise. At this time, air flows only through the opening 56a. On the other hand, the valve body 56 rotates with the operation of the accelerator lever 20 that increases the engine speed, thereby reducing the throttle amount.

  The opening 56a of the valve body 56 has an opening area determined on the basis of intake noise and intake resistance, and this opening area has a predetermined ratio with respect to the flow area (inner pipe area) of the intake pipe 40. It is set to be.

  Here, when the flow passage area of the intake pipe 40, that is, the air flow area in a place other than the throttle valve 50 is S1, and the air flow area in the throttle valve 50 is S2, the volume reduction of the intake noise is simplified. 10 × Log (S1 / S2)]. For this reason, the volume reduction increases as the flow area ratio (S1 / S2), that is, the throttle amount increases, so that the silencing effect can be increased by narrowing the silencing throttle valve 50.

  Thus, when the flow area ratio (S1 / S2), that is, the throttle amount is increased, there is a problem whether the intake resistance pressure does not increase accordingly. However, since the flow passage area of the intake pipe 40 is set based on the intake amount at the maximum output of the engine 14, even if the intake pipe 40 is throttled to some extent in the low engine rotation region, the engine performance is affected. Hard to give. Thus, the opening 56a of the valve body 56 is set to an opening area that exhibits a silencing effect in the low engine rotation region and does not deteriorate the engine performance.

  On the other hand, when the accelerator lever 20 is operated in the direction of increasing the engine speed, the valve element 56 of the silencer throttle valve 50 is rotated so as to reduce the throttle amount. At this time, air flows not only through the opening 56 a of the valve body 56 but also through the gap between the valve body 56 and the intake pipe 40. Further, when the valve body 56 faces in a direction parallel to the air flow direction, there is a possibility that almost no air flows through the opening 56a. Therefore, when the engine speed is increased, the throttle amount is reduced accordingly, and the intake resistance pressure is also reduced. At this time, no engine noise is generated because the engine speed increases.

  Thus, in the silencer according to the present embodiment, since the silencer throttle valve 50 is connected to the accelerator lever 20 via the second cable 60, when the accelerator lever 20 is operated, the throttle valve 50 is correspondingly operated. The throttle amount in the intake pipe 40 is changed. At this time, when the accelerator lever 20 is operated to increase the engine speed, the throttle valve 50 moves to reduce the throttle amount via the second cable 60, while the accelerator lever 20 is operated to decrease the engine speed. When this happens, the throttle valve 50 moves to increase the amount of throttle. That is, the muffled noise generated in the low rotation region is silenced, while the suction resistance is reduced in the high rotation region where the intake amount increases.

  Therefore, it is possible to suppress an increase in intake resistance in the high rotation range while reducing intake noise in the low rotation range without requiring electrical control. Further, since no control means is required, intake noise can be reduced at a low cost. Further, since the control means does not fail or malfunction, the intake noise can be reliably reduced.

  In the present embodiment, the silencer throttle valve 50 is installed in the second intake pipe 44, but the silencer throttle valve 50 may be installed in the first intake pipe 42 instead. The silencer throttle valve 50 in this case can be configured in the same manner as the silencer throttle valve 50 in the present embodiment.

  In the present embodiment, the silencer throttle valve 50 is configured by a so-called butterfly valve. However, the present invention is not limited to this, and is configured by various valves whose flow area can be changed depending on the rotation angle of a ball valve or the like. can do.

It is a perspective view which shows the upper turning body of the working machine with which the silencer which concerns on embodiment of this invention was applied. It is a perspective view which shows the structure which connects an accelerator lever and a governor lever in the said upper turning body in the state decomposed | disassembled for every component. FIG. 2 is a perspective view showing a state in which an intake pipe mainly around an engine is disassembled for each part in the upper swing body. It is a perspective view which shows the whole structure of the silencer throttle valve which comprises the said silencer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 14 Engine 20 Accelerator lever 40 Intake pipe 50 Silencing throttle valve 52 Main body part 54 Turning lever part 56 Valve body 60 2nd cable 60a Outer cable 60b Inner cable

Claims (4)

A muffler for reducing noise associated with engine intake,
A silencer throttle valve provided in the intake pipe of the engine;
A connecting member that mechanically connects the accelerator lever for adjusting the rotational speed of the engine and the silencer throttle valve;
The silencer throttle valve reduces the throttle amount by operating the accelerator lever that increases the engine speed, while increasing the throttle amount by operating the accelerator lever that decreases the engine speed. A muffler that is connected to an accelerator lever.   2. The connecting member includes an outer cable held by an engine, and an inner cable that is inserted into the outer cable so as to be movable forward and backward and connects the accelerator lever and the silencer throttle valve. The silencer described in 1.   The silencer throttle valve includes an annular main body portion having substantially the same inner diameter as the intake pipe, a rotating lever portion having a rotating shaft passing through the main body portion in a direction orthogonal to the axis of the main body portion, and the main body portion. The valve body which is arrange | positioned inside and rotates around the rotation axis | shaft of the said rotation lever part and changes a flow-path area according to a rotation angle is provided. Silencer.   The valve body is formed in a flat plate shape having an outer diameter corresponding to the inner diameter of the main body portion, and an opening portion having a predetermined area ratio with respect to the flow passage area of the intake pipe is provided in the central portion. The silencer according to claim 3, wherein

Images