Silencers and pneumatic tools

Abstract

To provide a noise reduction device for pneumatic tools that can achieve a higher noise reduction effect. [Solution] The silencing device 30 is attached to the tool exhaust port 22 of the pneumatic tool 1. The silencing device 30 comprises a device body 32 and a bag body 34. The device body 32 has a flow path 46 extending from an opening 42 communicating with the tool exhaust port 22 to a closed end 44, and a through passage 48 that penetrates the device body 32 in a direction intersecting the longitudinal axis L at a position between the opening 42 and the closed end 44. The bag body 34 has an expansion chamber 56 communicating with the through passage 48, and an exhaust hole 58 that connects the expansion chamber 56 to the outside space at a position away from the through passage 48 in the direction of the longitudinal axis L. The exhaust gas discharged from the tool exhaust port 22 flows through the flow path 46 in the direction of the longitudinal axis L, passes through the through passage 48 and enters the expansion chamber 56 in a direction intersecting the longitudinal axis L, is blown onto the inner circumferential surface 34a of the bag body 34, flows within the expansion chamber 56 in the direction of the longitudinal axis L, and is exhausted to the outside space through the exhaust hole 58.

Description

Technical Field

[0001] The present invention relates to a silencing device attached to an exhaust port of a pneumatic tool and a pneumatic tool equipped with the silencing device.

Background Art

[0002] A pneumatic tool having an air motor driven by compressed air as a drive source is known. As such a pneumatic tool, for example, there is a belt-type grinding tool provided with an endless grinding belt wound between a drive pulley and an idle pulley (Patent Document 1). This belt-type grinding tool rotates the endless grinding belt by rotationally driving the drive pulley with an air motor, and performs a grinding operation by pressing the rotating endless grinding belt against a workpiece.

[0003] The compressed air supplied to the belt-type grinding tool is discharged from the exhaust port of the tool after rotationally driving the air motor. Usually, in order to reduce the exhaust noise, a silencing device is attached to the exhaust port. The conventional silencing device attached to this belt-type grinding tool is composed of a cylindrical member and a bag-shaped member attached around it. The exhaust discharged from the exhaust port of the tool passes through the cylindrical member of the silencing device in the longitudinal direction and directly enters the bag-shaped member, diffuses in the bag-shaped member, and then is discharged to the external space through the exhaust holes formed on its side surface.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The silencing device of the pneumatic tool is required to have higher sound attenuation in order to reduce the influence on the surrounding environment and the operator.

[0006] Therefore, the present invention aims to provide a noise-reducing device for pneumatic tools that can achieve a higher noise reduction effect, and a pneumatic tool equipped with such a noise-reducing device. [Means for solving the problem]

[0007] In other words, the present invention is A device body to be attached to the tool exhaust port of a pneumatic tool, the device body having a flow path extending from an opening communicating with the tool exhaust port to a closed end, and a through passage that penetrates the device body and communicates with the flow path in a direction intersecting the longitudinal axis of the flow path at a position between the opening and the closed end, A bag attached to the main body of the apparatus, having an expansion chamber that communicates with the through passage and extends in the direction of the longitudinal axis, and an exhaust hole that connects the expansion chamber to the outside space at a position away from the through passage in the direction of the longitudinal axis, Equipped with, The present invention provides a sound-dampening device in which at least a portion of the exhaust gas discharged from the tool exhaust port flows through the passage in the direction of the longitudinal axis, passes through the through passage and enters the expansion chamber in a direction intersecting the longitudinal axis, is blown onto the inner circumferential surface of the bag body, flows within the expansion chamber in the direction of the longitudinal axis, and is discharged into the outside space from the exhaust hole.

[0008] In this noise-reducing device, the exhaust gas discharged from the tool exhaust port of the pneumatic tool is blown onto the inner surface of the bag body through a through passage in a direction intersecting the longitudinal axis of the flow path, thereby reducing the force of the exhaust gas and achieving a significant noise reduction effect.

[0009] Furthermore, the through passages can be arranged in a staggered pattern around the circumferential direction of the main body of the device.

[0010] Also, The expansion chamber further comprises a coil-shaped member that is positioned outside the main body of the device so as to cover the through passage and extends in the direction of the longitudinal axis, At least a portion of the exhaust gas exiting the through passage can be blown onto the inner surface of the bag through the gaps in the coil-shaped member.

[0011] By passing the relatively forceful exhaust gases exiting the passage through the gaps in the coil-shaped members, turbulence can be created. This makes it possible to achieve an even greater noise reduction effect.

[0012] Furthermore, the exhaust port can consist of a plurality of exhaust ports that open in a direction intersecting the longitudinal axis.

[0013] Furthermore, the closed end of the device body can be made to have a conical shape.

[0014] The present invention further, A tool body having a tool air intake port, a tool exhaust port, and a tool flow path extending from the tool air intake port to the tool exhaust port, An air motor provided on the tool body and driven by compressed air flowing through the tool passage, One of the above-mentioned silencers attached to the tool exhaust port, We provide pneumatic tools equipped with the following features.

[0015] Hereinafter, embodiments of the sound-dampening device and pneumatic tool according to the present invention will be described with reference to the attached drawings. [Brief explanation of the drawing]

[0016] [Figure 1] This is a side cross-sectional view of a pneumatic tool according to one embodiment of the present invention. [Figure 2] Figure 1 is a cross-sectional view of the upper surface of a pneumatic tool. [Figure 3] This is a cross-sectional view of a sound-dampening device according to one embodiment of the present invention. [Figure 4] Figure 3 is an external side view of the main body of the sound-dampening device. [Figure 5] Figure 3 is a perspective view of the external appearance of the sound-dampening device's bag-shaped body.

Best Mode for Carrying Out the Invention

[0017] As shown in FIGS. 1 and 2, an air tool 1 according to an embodiment of the present invention includes a tool body 10, an air motor 12 disposed within the tool body 10, a drive pulley 14 rotated by the air motor 12, and an idle pulley 16 rotatably disposed on the tool body 10. It is a belt-type grinding tool that uses an endless grinding belt 18 mounted between the drive pulley 14 and the idle pulley 16. The tool body10 includes a tool air inlet 20 for receiving compressed air supplied from an external compressed air supply source and a tool exhaust port 22 for discharging the exhaust after rotating the air motor 12. A tool flow path 24 through which compressed air passes is formed between the tool air inlet 20 and the tool exhaust port 22. The air motor 12 is disposed in the middle of the tool flow path 24. By pressing a lever 26 disposed on the upper part of the tool body 10, the switch valve 28 is pressed and the tool flow path 24 is released. Then, the compressed air supplied from the tool air inlet 20 passes through the tool flow path 24 and reaches the air motor 12, rotating the air motor 12. When the air motor 12 is rotationally driven, the drive pulley 14 rotates, thereby rotating the endless grinding belt 18. By pressing the rotating endless grinding belt 18 against the workpiece, the grinding operation of the workpiece can be performed. The compressed air that has rotationally driven the air motor 12 exits the air motor 12, passes through the tool flow path 24, and is discharged from the tool body 10 through the tool exhaust port 22.

[0018] A silencing device 30 according to an embodiment of the present invention is attached to the tool exhaust port 22.

[0019] The silencing device 30 includes a device body 32 attached to the tool exhaust port 22, a bag body 34 attached to the device body 32, and a coiled member 36 disposed within the bag body 34.

[0020] As shown in Figures 3 and 4, the device body 32 consists of a cylindrical side wall portion 38 and a conical end wall portion 40. The device body 32 has a flow path 46 that extends along the longitudinal axis L from the opening 42 to the closed end portion 44, and a through passage 48 that penetrates the side wall portion 38 and communicates with the flow path 46 in a direction intersecting the longitudinal axis L at a position between the opening 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 perpendicular to the longitudinal axis L. In addition, multiple through passages 48 are arranged in a staggered (zigzag) pattern in the circumferential direction of the device body 32. By staggering the arrangement, it is possible to arrange more through passages 48 while increasing the diameter of each through passage 48. The side wall portion 38 has a male screw portion 50 for attaching the silencer 30 to the tool exhaust port 22 and an annular recess 52 for attaching the bag body 34.

[0021] As shown in Figures 3 and 5, the bag 34 has a bag-like shape that extends long in the direction of its longitudinal axis L. The bag 34 is made of a flexible material such as rubber or resin. The bag 34 is attached to the outer surface 32a of the device body 32 by fitting an annular projection 54 that protrudes radially inward into an annular recess 52 of the device body 32. The bag 34 defines an expansion chamber 56 that extends inward along the longitudinal axis L. The expansion chamber 56 communicates with the through passage 48. The bag 34 has exhaust holes 58 located away from the through passage 48 in the direction of the longitudinal axis L. Multiple exhaust holes 58 are formed so as to open in a direction intersecting the longitudinal axis L.

[0022] As shown in Figure 3, the coil-shaped member 36 is positioned between the device body 32 and the bag body 34 within the expansion chamber 56. In this embodiment, the coil-shaped member 36 is a coil spring. One end 60 of the coil-shaped member 36 abuts against the locking surface 62 of the device body 32. The other end 64 of the coil-shaped member 36 abuts against the locking surface 66 of the bag body 34. The coil-shaped member 36 is positioned outside the device body 32 so as to cover the through passage 48 and extends in the direction of the longitudinal axis L.

[0023] When the pneumatic tool 1 is driven and compressed air is discharged as exhaust from the tool air inlet 20, the exhaust enters the flow path 46 of the silencer 30 through the opening 42 and flows through the flow path 46 in the direction of the longitudinal axis L. The exhaust enters the expansion chamber 56 from the flow path 46 through the through passage 48 in a direction intersecting the longitudinal axis L. Most of the exhaust that leaves the through passage 48 is blown onto the inner circumferential surface 34a of the bag body 34 through the gaps in the coil-shaped member 36. The exhaust is disturbed and becomes turbulent as it passes through the gaps in the coil-shaped member 36. The exhaust that is blown onto the inner circumferential surface 34a of the bag body 34 changes direction and flows through the expansion chamber 56 in the direction of the longitudinal axis L. The remaining exhaust that leaves the through passage 48 does not immediately pass through the gaps in the coil-shaped member 36, but flows to some extent inside the coil-shaped member 36 in the direction of the longitudinal axis L before passing through the gaps in the coil-shaped member 36 and reaching the outside of the coil-shaped member 36. The exhaust gas that has passed through the coil-shaped member 36 is finally discharged from the exhaust port 58 into the external space outside the silencer 30.

[0024] In the pneumatic tool 1, the exhaust gas discharged from the tool exhaust port 22 of the pneumatic tool 1 passes through the silencer 30 having the above-described configuration, making it possible to reduce exhaust noise more significantly compared to conventional silencers. In particular, by directing the exhaust gas, which is directed in a direction intersecting the longitudinal axis L through the through passage 48, onto the inner circumferential surface 34a of the bag body 34 and diffusing it into the expansion chamber 56, the force of the exhaust gas is reduced, making it possible to obtain a large noise reduction effect. In addition, a noise reduction effect can be obtained by rectifying the exhaust gas as it passes through the flow path 46 extending in the direction of the longitudinal axis L, thereby suppressing turbulence in the airflow. Furthermore, by passing the expansion chamber 56 to the exhaust port 58, which is located away from the through passage 48, the flow velocity when it is finally discharged from the exhaust port 58 can be kept low, and this also provides a noise reduction effect.

[0025] Although embodiments of the present invention have been described above, the present invention is not limited to these embodiments. For example, a readily available coil spring is used as the coil-shaped member, but it is not necessarily required to be a coil spring. Also, while a greater sound-dampening effect can be expected by arranging a coil-shaped member, it is not necessary to provide a coil-shaped member. The arrangement and number of through passages and exhaust holes can be changed as appropriate. In the above embodiments, the pneumatic tool is a belt-type grinding tool, but other types of pneumatic tools such as screwdrivers or chiselers driven by compressed air may also be used. [Explanation of symbols]

[0026] 1. Pneumatic tools 10 Tool body 12 Air motors 14 Drive Pulley 16 Idler Pulley 18 Endless grinding belt 20 Tool air supply port 22 Tool exhaust port 24 Tool flow path 26 Lever 28 Switch valve 30 Silencer 32 Main unit of the device 32a Outer surface 34 Bag body 34a Inner surface 36 Coil-shaped member 38 Side wall section 40 End wall section 42 Opening 44 Closed end 46 channels 48 Throughway 50 Male threaded section 52 Annular recess 54 Annular projection 56 Expansion chamber 58 Exhaust vents 60 one end 62 Locking surface 64 Other end 66 Locking surface L Longitudinal axis

Claims

1. A device body to be attached to the tool exhaust port of a pneumatic tool, the device body having a flow path extending from an opening communicating with the tool exhaust port to a closed end, and a through passage that penetrates the device body and communicates with the flow path in a direction intersecting the longitudinal axis of the flow path at a position between the opening and the closed end, A bag attached to the main body of the apparatus, having an expansion chamber that communicates with the through passage and extends in the direction of the longitudinal axis, and an exhaust hole that connects the expansion chamber to the outside space at a position away from the through passage in the direction of the longitudinal axis, Equipped with, A sound-dampening device in which at least a portion of the exhaust gas discharged from the tool exhaust port flows through the passage in the direction of the longitudinal axis, enters the expansion chamber through the through passage in a direction intersecting the longitudinal axis, is blown onto the inner circumferential surface of the bag body, flows within the expansion chamber in the direction of the longitudinal axis, and is discharged into the outside space from the exhaust hole.

2. The sound-dampening device according to claim 1, wherein the through passages are arranged in a staggered pattern in the circumferential direction of the main body of the device.

3. The expansion chamber further comprises a coil-shaped member that is positioned outside the main body of the device so as to cover the through passage and extends in the direction of the longitudinal axis, The sound-dampening device according to claim 1, wherein at least a portion of the exhaust gas exiting the through passage is blown onto the inner surface of the bag body through the gaps in the coil-shaped member.

4. The sound-dampening device according to claim 1, wherein the exhaust port consists of a plurality of exhaust ports that open in a direction intersecting the longitudinal axis.

5. The sound-dampening device according to claim 1, wherein the closed end of the device body has a conical shape.

6. A tool body having a tool air intake port, a tool exhaust port, and a tool flow path extending from the tool air intake port to the tool exhaust port, An air motor provided on the tool body and driven by compressed air flowing through the tool passage, A sound-dampening device according to any one of claims 1 to 5, attached to the tool exhaust port, A pneumatic tool equipped with the following features.

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