Silencing device and pneumatic tool

Abstract

The invention provides a silencing device for a pneumatic tool, which can obtain a high silencing effect. The silencer is mounted at a tool exhaust port of the pneumatic tool. The muffler device is provided with a device main body (32) and a bag body (34). The device main body has a flow path (46) extending from an opening (42) communicating with the tool exhaust port to a closed end (44), and a through path (48) penetrating the device main body in a direction intersecting the longitudinal axis (L) at a position between the opening and the closed end. The bag body has an expansion chamber (56) that communicates with the through-passage, and a vent hole that communicates the expansion chamber with the external space at a position separated from the through-passage in the longitudinal axis direction. The exhaust gas discharged from the tool exhaust port flows in the direction of the longitudinal axis in the flow path, flows into the expansion chamber through the through path in a direction intersecting the longitudinal axis, is blown toward the inner peripheral surface of the bag body, flows in the direction of the longitudinal axis in the expansion chamber, and is discharged to the outside space from the exhaust hole.

Description

Technical Field

[0001] The present invention relates to a silencer installed at the exhaust port of a pneumatic tool, and a pneumatic tool having the silencer. Background Technology

[0002] Pneumatic tools that use a pneumatic motor driven by compressed air as a drive source are known. For example, there is a belt grinding tool (Patent Document 1) that has an annular grinding belt wound between a drive pulley and a freewheeling pulley. This belt grinding tool rotates the annular grinding belt by rotating the drive pulley using a pneumatic motor, and presses the rotating annular grinding belt against the workpiece, thereby performing a grinding operation.

[0003] Compressed air supplied to a belt grinding tool is discharged from the tool's exhaust port after driving a pneumatic motor to rotate. Typically, a silencer is installed at the exhaust port to reduce exhaust noise. The silencer installed in this conventional belt grinding tool consists of a cylindrical component and a bag-shaped component installed around the cylindrical component. Exhaust air discharged from the tool's exhaust port passes along its length through the cylindrical component of the silencer and directly into the bag-shaped component. After diffusing within the bag-shaped component, it is discharged to the external space through exhaust holes formed on its side.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2008-194769 Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] To minimize the impact on the surrounding environment and operators, the silencer of pneumatic tools needs to have high noise reduction performance.

[0009] Therefore, the object of the present invention is to provide a silencer for a pneumatic tool that achieves a high level of noise reduction, and a pneumatic tool having such a silencer.

[0010] Methods for solving problems

[0011] That is, the present invention provides a noise reduction device, wherein,

[0012] The silencing device includes:

[0013] A device body installed at the tool exhaust port of a pneumatic tool, the device body having an opening communicating with the tool exhaust port, a flow path extending from the opening to a closed end, and a through passage penetrating the device body and communicating with the flow path at a position between the opening and the closed end in a direction intersecting the length axis of the flow path; and

[0014] The bag body installed on the main body of the device has an expansion chamber that communicates with the through passage and extends along the length axis, and an exhaust port located away from the through passage in the length axis, allowing the expansion chamber to communicate with the external space.

[0015] At least a portion of the exhaust gas discharged from the tool's exhaust port flows along the length axis in the flow path, flows into the expansion chamber through the through passage in a direction intersecting the length axis, is blown toward the inner circumferential surface of the bag body and flows along the length axis in the expansion chamber, and is discharged to the external space from the exhaust port.

[0016] In this silencing device, the exhaust gas discharged from the tool exhaust port of the pneumatic tool passes through the through passage in a direction intersecting the length axis of the flow path and is blown toward the inner circumferential surface of the bag body, thereby reducing the momentum of the exhaust gas and achieving a large silencing effect.

[0017] Alternatively, multiple through passages may be arranged in an interlaced (staggered, serrated) manner on the circumference of the main body of the device.

[0018] Alternatively, the silencing device may also include a spiral member disposed on the outside of the device body within the expansion chamber in a manner that covers the through passage, and extending along the direction of the length axis.

[0019] At least a portion of the exhaust gas flowing out from the through passage passes through the gaps in the spiral member and is blown toward the inner circumferential surface of the bag.

[0020] By passing the relatively forceful exhaust flow from the through passage through the gaps in the spiral member, turbulence can be generated. This results in a further reduction in noise.

[0021] Alternatively, the vent may consist of a plurality of vents that open in a direction intersecting the length axis.

[0022] Alternatively, the blocking end of the device body may have a conical shape.

[0023] The present invention also provides a pneumatic tool, wherein,

[0024] The pneumatic tool includes:

[0025] The tool body has a tool air supply port, a tool exhaust port, and a tool flow path extending from the tool air supply port to the tool exhaust port;

[0026] A pneumatic motor, disposed in the tool body and driven by compressed air flowing in the tool path; and

[0027] A silencer device of any of the above-mentioned types installed at the exhaust port of the tool.

[0028] Hereinafter, embodiments of the silencing device and pneumatic tool involved in the present invention will be described based on the accompanying drawings. Attached Figure Description

[0029] Figure 1 This is a side sectional view of a pneumatic tool according to an embodiment of the present invention.

[0030] Figure 2 yes Figure 1 A partial sectional view of the pneumatic tool from the top.

[0031] Figure 3 This is a cross-sectional view of a noise reduction device according to an embodiment of the present invention.

[0032] Figure 4 yes Figure 3 A side view of the main body of the noise reduction device.

[0033] Figure 5 yes Figure 3 A three-dimensional view of the bag containing the sound-absorbing device.

[0034] Explanation of reference numerals in the attached figures

[0035] 1. Pneumatic tools

[0036] 10. Tool Body

[0037] 12 pneumatic motors

[0038] 14 Drive pulleys

[0039] 16 Idle pulley

[0040] 18 Annular grinding belt

[0041] 20 Tool air supply ports

[0042] 22 Tool vent

[0043] 24 Tool Flow Path

[0044] 26 strokes

[0045] 28 Switch valve

[0046] 30. Silencing device

[0047] 32. Main body of the device

[0048] 32a Outer Peripheral Surface

[0049] 34 bags

[0050] 34a Inner circumferential surface

[0051] 36 Spiral components

[0052] 38 Side wall portion

[0053] 40 end wall

[0054] 42 Opening

[0055] 44. Closure end

[0056] 46 flow path

[0057] 48 Through-passage

[0058] 50 External thread section

[0059] 52. Annular recess

[0060] 54. Annular protrusions

[0061] 56 Expansion Chamber

[0062] 58 Exhaust holes

[0063] 60 One end

[0064] 62 Card Stop Surface

[0065] 64 The other end

[0066] 66 Card Stop Surface

[0067] L is the length axis. Detailed Implementation

[0068] The pneumatic tool 1 according to one embodiment of the present invention is as follows: Figure 1 as well as Figure 2The pneumatic tool 1 shown includes a tool body 10, a pneumatic motor 12 disposed within the tool body 10, a drive pulley 14 rotated by the pneumatic motor 12, and a freewheeling pulley 16 rotatably disposed within the tool body 10. The pneumatic tool 1 is a belt grinding tool with an annular grinding belt 18 mounted between the drive pulley 14 and the freewheeling pulley 16. The tool body 10 has a tool air inlet 20 for receiving compressed air supplied from an external compressed air supply source, and a tool exhaust outlet 22 for discharging exhaust air after the pneumatic motor 12 has been driven to rotate. A tool flow path 24 for compressed air to pass through is formed between the tool air inlet 20 and the tool exhaust outlet 22. The pneumatic motor 12 is disposed midway through the tool flow path 24. The tool flow path 24 is opened by pressing a switch valve 28, which is located on the upper part of the tool body 10. In this way, compressed air supplied from the tool air inlet 20 reaches the pneumatic motor 12 through the tool flow path 24, causing the pneumatic motor 12 to rotate. When the pneumatic motor 12 is rotated, the drive pulley 14 rotates, thereby rotating the annular grinding belt 18. By pressing the rotating annular grinding belt 18 against the workpiece, grinding operations on the workpiece can be performed. The compressed air that drives the pneumatic motor 12 flows out of the pneumatic motor 12 and through the tool flow path 24, and is discharged from the tool body 10 through the tool exhaust port 22.

[0069] A silencer 30 according to an embodiment of the present invention is installed at the tool exhaust port 22.

[0070] The silencer 30 includes a device body 32 installed at the tool exhaust port 22, a bag body 34 installed at the device body 32, and a spiral member 36 disposed within the bag body 34.

[0071] like Figure 3 as well as Figure 4 As shown, the device body 32 is composed of a cylindrical sidewall portion 38 and a conical endwall portion 40. The device body 32 has a flow path 46 extending from the opening portion 42 along the length axis L to the closed end portion 44, and a through passage 48 passing through the sidewall portion 38 and connecting to the flow path 46 in a direction intersecting the length axis L at a position between the opening portion 42 and the closed end portion 44. The closed end portion 44 has a conical shape. In this embodiment, the through passage 48 extends in a direction orthogonal to the length axis L. In addition, multiple through passages 48 are arranged in an alternating (stinged, serrated) manner in the circumferential direction of the device body 32. By setting it in an alternating manner, the diameter of each through passage 48 can be increased, and more through passages 48 can be arranged. An external thread portion 50 for mounting the silencer 30 to the tool exhaust port 22 and an annular recess 52 for mounting the bag body 34 are formed on the sidewall portion 38.

[0072] like Figure 3 as well as Figure 5As shown, the bag body 34, as a whole, has a long, bag-like shape extending along the length axis L. The bag body 34 is formed of a flexible material such as rubber or resin. The bag body 34 is mounted on the outer peripheral surface 32a of the device body 32 by inserting an annular protrusion 54 protruding radially inward into an annular recess 52 of the device body 32. An expansion chamber 56 extending along the length axis L is defined on the inner side of the bag body 34. The expansion chamber 56 communicates with the through passage 48. The bag body 34 has an exhaust port 58 located away from the through passage 48 in the direction of the length axis L. Multiple exhaust ports 58 are formed, opening in a direction intersecting the length axis L.

[0073] like Figure 3 As shown, a helical member 36 is disposed within the expansion chamber 56 between the device body 32 and the bag body 34. In this embodiment, the helical member 36 is a helical spring. One end 60 of the helical member 36 abuts against the locking surface 62 of the device body 32. The other end 64 of the helical member 36 abuts against the locking surface 66 of the bag body 34. The helical member 36 is disposed on the outside of the device body 32 in a manner that covers the through passage 48 and extends in the direction of the length axis L.

[0074] When the pneumatic tool 1 is driven and compressed air is discharged from the tool air supply port 20 as exhaust, the exhaust flows from the opening 42 into the flow path 46 of the silencer 30 and flows along the length axis L within the flow path 46. The exhaust flows from the flow path 46 through the through passage 48 and into the expansion chamber 56 in a direction intersecting the length axis L. Most of the exhaust exiting the through passage 48 passes through the gap of the spiral member 36 and is blown toward the inner circumferential surface 34a of the bag body 34. The exhaust becomes turbulent as it passes through the gap of the spiral member 36. The exhaust blown to the inner circumferential surface 34a of the bag body 34 changes direction and flows along the length axis L within the expansion chamber 56. The remaining exhaust exiting the through passage 48 does not immediately pass through the gap of the spiral member 36, but flows to some extent along the length axis L inside the spiral member 36 before passing through the gap of the spiral member 36 and reaching the outside of the spiral member 36. The exhaust gas after passing through the spiral member 36 is finally discharged from the exhaust port 58 into the external space outside the muffler 30.

[0075] In this pneumatic tool 1, the exhaust gas discharged from the tool exhaust port 22 passes through a silencer 30 with the structure described above, thereby significantly reducing exhaust noise compared to structures with conventional silencers. Specifically, by blowing exhaust gas through the through passage 48 toward the inner circumferential surface 34a of the bag body 34 and causing it to diffuse within the expansion chamber 56, the exhaust momentum is reduced, resulting in a significant silencing effect. Furthermore, the exhaust gas is rectified as it passes through the flow path 46 extending along the length axis L, temporarily suppressing airflow turbulence, thus also achieving a silencing effect. Moreover, as the gas passes through the expansion chamber 56 and reaches the exhaust port 58 exiting the through passage 48, the flow velocity of the gas when it finally exits from the exhaust port 58 is reduced, further contributing to the silencing effect.

[0076] The embodiments of the present invention have been described above, but the present invention is not limited to these embodiments in any way. For example, a readily available helical spring is used as the helical component, but it is not necessary to use a helical spring. In addition, a greater noise reduction effect can be expected by configuring a helical component, but the helical component may not be necessary. The configuration and number of the through passage and the exhaust port can be appropriately changed. In the above embodiments, the pneumatic tool is a belt grinding tool, but it may also be other types of pneumatic tools such as a driver or a chisel driven by compressed air.

Claims

1. A muffling device, wherein the muffling device is provided with: a device main body mounted to a tool exhaust port of a pneumatic tool, the device main body having an opening portion communicated with the tool exhaust port, a flow path extending from the opening portion to a closed end portion, and a through path penetrating the device main body in a direction intersecting a length axis of the flow path and communicated to the flow path at a position between the opening portion and the closed end portion; and a bag body mounted to the device main body, the bag body having an expansion chamber communicated with the through path and extending in the direction of the length axis, and an exhaust hole communicating the expansion chamber with an external space at a position apart from the through path in the direction of the length axis, at least a portion of exhaust gas discharged from the tool exhaust port flows in the direction of the length axis of the flow path, flows into the expansion chamber in a direction intersecting the length axis through the through path, is blown against an inner peripheral surface of the bag body to flow in the direction of the length axis in the expansion chamber, and is discharged to the external space from the exhaust hole.

2. The muffling device according to claim 1, wherein the through paths are arranged in a staggered manner in a circumferential direction of the device main body.

3. The muffling device according to claim 1, wherein the muffling device is further provided with a helical member arranged outside the device main body in the expansion chamber in a manner covering the through paths and extending in the direction of the length axis, at least a portion of the exhaust gas flowing from the through paths passes through gaps of the helical member and is blown against the inner peripheral surface of the bag body.

4. The muffling device according to claim 1, wherein the exhaust hole is composed of a plurality of exhaust holes opened in a direction intersecting the length axis.

5. The muffling device according to claim 1, wherein the closed end portion of the device main body has a conical shape.

6. A pneumatic tool, wherein the pneumatic tool is provided with: a tool main body having a tool air supply port, a tool exhaust port, and a tool flow path extending from the tool air supply port to the tool exhaust port; a pneumatic motor provided to the tool main body and driven by compressed air flowing in the tool flow path; and the muffling device according to any one of claims 1 to 5 mounted to the tool exhaust port. ​

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