TW201703944A - Pneumatic tool provided with helmholtz silencing device - Google Patents

Abstract

To reduce noise from an exhaust path of a pneumatic tool. In an exhaust path (30) in a housing (16) of a pneumatic tool (10), a silencing member (40) is provided along the longitudinal direction of the exhaust path such that the inside of the exhaust path is divided into: resonance chambers (46, 48) extending in the longitudinal direction of the exhaust path; and an exhaust passage (50) that extends in the longitudinal direction so as to be adjacent to the resonance chambers and separated from the resonance chambers, and receives exhaust from a motor chamber (20) and passes the exhaust to a downstream side outlet (30a). The silencing member (40) is provided with a hole (54) that connects the exhaust passage (50) and the resonance chambers (46, 48) to each other. The hole (54) and the resonance chambers (46, 48) form a silencing chamber using Helmholtz resonance.

Description

Pneumatic tool with Helmholtz type silencer

The present invention relates to a pneumatic tool having a Helmholtz type silencer.

An air-type belt type grinder that operates with compressed air as a driving source or a pneumatic tool such as a torque wrench connects an external air compressor to an air supply path of the tool housing to supply compressed air to the air motor. The exhaust gas from the air motor is exhausted to the outside through the exhaust passage of the casing.

Like this pneumatic tool, a lot of effort has been made to reduce the noise caused by the exhaust of the air motor. For example, in the pneumatic tool disclosed in Patent Document 1, a cylindrical member (muffler) extending along the exhaust passage is provided in the exhaust passage, and the exhaust passage is partitioned into a coaxial inner passage and outer side. In the passage, on the upstream side and the downstream side of the tubular member, a plurality of holes are provided at intervals in the circumferential direction, and a portion of the exhaust gas flowing downstream from the upstream side of the exhaust passage is opened from the upstream side. The passage toward the outer side is branched (dispersed), and flows into the exhaust gas flowing from the downstream side hole and flowing in the inner passage, and the split (distribution) of the exhaust gas, the hole or the passage wall Friction to achieve a sound-absorbing effect. In the pneumatic tool disclosed in Patent Document 2, glass wool (damping material) is filled in the exhaust passage to achieve a sound absorbing effect.

Further, in the technique of reducing the noise caused by the gas flowing through the flow path, Patent Document 3 discloses a Helmholtz type muffler which is provided with a resonance box for reducing the intake sound of the engine ( The resonator is connected to the suction passage from a side surface of the intake passage through a small-diameter passage.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Invention No. 3029092

[Patent Document 2] Japanese Patent Laid-Open No. 5-138551

[Patent Document 3] Japan Special Fair 3-4743

SUMMARY OF THE INVENTION It is an object of the present invention to provide a pneumatic tool having a Helmholtz type silencer having a simple structure that has not been conventionally available.

That is, the present invention provides a pneumatic tool having a Helmholtz type silencer, which is characterized by: a housing that includes a motor chamber that houses a pneumatic motor, an air supply path that supplies compressed air to the motor chamber, and a passage for exhaust gas from the motor chamber to pass from the downstream side outlet toward the outside a discharge exhaust passage; and a sound absorbing member disposed in the exhaust passage along a longitudinal direction of the exhaust passage, and dividing the exhaust passage into: along the exhaust passage a resonance chamber extending in a longitudinal direction and an exhaust passage adjacent to the resonance chamber, extending in the longitudinal direction and partitioned from the resonance chamber, and receiving exhaust gas from the motor chamber The exhaust gas passes through the downstream side outlet, and the sound absorbing member is provided with a hole that communicates the exhaust passage and the resonance chamber, and the hole and the resonance chamber form a muffler chamber that resonates with Helmholtz .

Since the pneumatic tool of the present invention has the Helmholtz type muffler as described above, noise emitted to the outside through the exhaust passage can be suppressed.

Specifically, the exhaust passage extends linearly from the downstream side outlet toward the motor chamber toward the upstream side, and the noise damper member is inserted from the downstream side outlet toward the upstream side having the motor chamber, and is inserted into the exhaust passage. The exhaust passage is divided into: the resonance chamber and the exhaust passage.

In one embodiment, the sound absorbing member is provided with the horse from the downstream side outlet in a state of being inserted into the exhaust passage. The upstream side of the chamber is a plate-shaped partition wall extending in a straight line, and the periphery of the partition wall is engaged with the exhaust passage wall surface on which the exhaust passage is drawn, and the exhaust passage can be divided into: the resonance chamber And the exhaust passage. At this time, the hole is provided in the plate-shaped partition wall.

By doing so, the Helmholtz type silencer can be equipped with a simple configuration.

More specifically, the sound absorbing member has a plate-shaped second partition wall which is spaced apart from the plate-shaped partition wall and is parallel, and the sound absorbing member is inserted into the exhaust passage. In the state, the periphery of the second partition wall is engaged with the exhaust passage wall surface on which the exhaust passage is drawn, and the two partition walls form a first and second resonance between the exhaust wall surfaces and the exhaust passage wall surface. In the chamber, the exhaust passage is defined between the two partition walls, and the second resonance chamber and the exhaust passage are connected to each other by a hole formed in the second partition wall.

More specifically, the first and second resonance chambers are connected by a communication passage that traverses the exhaust passage.

Further, the sound absorbing member may have a connecting wall that connects the downstream end portions of the two divided walls.

At this time, in the exhaust passage, a sound absorbing material is provided in a space portion defined by the connecting wall and the two partition walls, and the sound absorbing material passes through the exhaust gas flowing from the upstream to the downstream, and performs the muffling. .

The housing has an exhaust duct that can define the exhaust passage.

The exhaust pipe system is detachable from the housing.

Hereinafter, embodiments of the pneumatic tool of the present invention will be described based on the drawings.

10‧‧‧Belt-type grinding tools

14‧‧‧Ring grinding belt

16‧‧‧Shell

18‧‧‧Air motor

20‧‧‧Motor room

22‧‧‧Motor storage unit

24‧‧‧ gas supply port

26‧‧‧Exhaust port

28‧‧‧ gas supply road

30‧‧‧Exhaust road

30a‧‧‧Export

30b‧‧‧Exhaust road wall

32‧‧‧Exhaust pipe

34‧‧‧Hands

35‧‧‧ operation keys

36‧‧‧Train component for exhaust direction change

38‧‧‧Opening and closing valve

40‧‧‧Muffling components

42‧‧‧1st dividing wall

42a‧‧‧Upper edge

42b‧‧‧ lower edge

42c‧‧‧ front edge

44‧‧‧2nd dividing wall

44a‧‧‧Upper edge

44b‧‧‧ lower edge

44c‧‧‧ front edge

45a‧‧‧ upper connecting wall

45b‧‧‧Lower connecting wall

46‧‧‧1st Resonance Room

48‧‧‧2nd Resonance Room

50‧‧‧Exhaust passage

52‧‧‧ sloping plate

52a‧‧‧ below

53‧‧‧Connected Road

54‧‧‧ hole

56‧‧‧Muffling materials

58‧‧‧ ribs

60‧‧‧ claws

Fig. 1 is a side view showing a belt type grinding tool according to an embodiment of the pneumatic tool of the present invention.

Fig. 2 is a top view of the belt type grinding tool of Fig. 1.

FIG. 3 is a cross-sectional view taken along line III-III of FIG. 1. FIG.

Fig. 4 is a sectional view taken along line IV-IV of Fig. 2;

Fig. 5 is a perspective view of a sound absorbing member inserted into an exhaust path of the belt type grinding tool set in Fig. 1.

The belt-type grinding tool 10 according to an embodiment of the pneumatic tool according to the present invention includes an annular grinding belt 14 that is stretched over a pulley 12 that is set at a front end (left end in the drawing). The annular grinding belt 14 is driven by a pneumatic motor 18 within the housing 16. The structural relationship between the annular grinding belt 14 and the air motor 18 in the belt type grinding tool is disclosed in, for example, Japanese Laid-Open Patent Publication No. 2008-194769, which is hereby incorporated by reference herein. .

The casing 16 has a cylindrical motor housing portion 22, and the motor housing portion 22 has a horse that houses a pneumatic motor (impeller motor) 18. The chamber 20 is provided with a gas supply port 24 that communicates with the motor chamber 20 and an exhaust port 26 in the peripheral wall portion of the motor housing portion 22. The housing 16 further has a handle portion 34 that accommodates the supply and exhaust pipe 32 provided with the air supply passage 28 and the exhaust passage 30 so that the air supply passage 28 and the exhaust passage 30 can be respectively connected. At the air supply port 24 and the exhaust port 26.

When the belt type grinding tool (pneumatic tool) 10 is used for the grinding operation, the air supply path 28 is connected to the external air compressor, and the operation key 35 mounted under the casing 16 is pressed to open the air supply path 28. The internal opening and closing valve 38 passes through the air supply passage 28 and the air supply port 24, and supplies compressed air to the motor chamber 20 to drive the motor 18. The exhaust gas from the motor chamber 20 passes through the exhaust port 26 and the exhaust passage 30, and is discharged toward the outside. At the right end of the exhaust passage 30 in the drawing, there is provided an exhaust direction changing pipe member 36 which changes the exhaust gas to a desired position by rotating the longitudinal axis of the exhaust passage 30 toward the center. direction.

In the present invention, a Helmholtz type muffler (resonator) as described below is provided in the exhaust passage 30 of the belt type grinding tool 10. The exhaust passage 30 extends in a straight line from the outlet 30a at the right end toward the exhaust port 26. The muffling member 40 is inserted and fixed from the outlet 30a toward the exhaust port 26 as shown in Fig. 5 . The muffling member 40 extends toward the longitudinal direction of the exhaust passage 30, and has a plate-shaped first partition wall 42 and a second partition wall 44 which are spaced apart from each other in the traverse direction of the exhaust passage 30; In the vicinity of the outlet 30a, the upper connecting wall 45a and the lower connecting wall 45b that connect the first partition wall 42 and the second partition wall 44 are in contact with the bottom surface 30c of the exhaust passage 30. The first partition wall 42 and the second partition wall 44 respectively define a row of the exhaust passage 30 at the upper edge 42a, the lower edge 42b, the front end edge 42c, and the upper edge 44a, the lower edge 44b, and the front end edge 44c. The air passage wall surface 30b is substantially engaged in a sealed state. The first partition wall 42 and the second partition wall 44 partition the inside of the exhaust passage 30 into a first resonance chamber 46 and a second resonance chamber 48 on the left and right sides, and an exhaust passage 50, which is an exhaust passage 50. Positioned between these resonance chambers, it extends toward the longitudinal direction of the exhaust passage 30, receives exhaust gas from the motor chamber 20, and allows the exhaust gas to pass toward the outlet 30a of the exhaust passage 30. In the illustrated example, an inclined plate 52 is attached to the left end portion of the sound absorbing member 40 in the drawing, and the inclined plate 52 is a lower portion that connects the first partition wall 42 and the second partition wall 44. A communication path 53 that connects the first resonance chamber 46 and the second resonance chamber 48 is formed between the lower surface 52a of the inclined plate 52 and the exhaust passage wall surface 30b, and the first resonance chamber 46 and the second resonance chamber 48 are formed. A single resonance chamber is formed. A single small hole 54 is formed in each of the first partition wall 42 and the second partition wall 44. The hole 54 and the resonance chamber form a Helmholtz type muffler that resonates with Helmholtz.

The muffling member 40 is permeable to the outlet 30a of the exhaust passage 30, and can be joined to the first partition 42 and the second partition 44 at a portion of the lower end of the sound absorbing member 40 that connects the wall 45b. A muffling material 56 such as glass wool is set in a thin manner. In the example of the figure, the right end portion of the first partition wall 42 and the second partition wall 44 is provided with a claw 60 that is pushed outward, and the claw 60 is engaged in the exhaust passage wall surface by being engaged. A hole (not shown) of 30b is fixed to the sound absorbing member 40. By pressing the claw 60 into the inner side, it is exposed from the hole, The sound absorbing member 40 can be taken out from the exhaust passage 30. Therefore, by replacing the sound absorbing member 40 from the exhaust passage 30, the sound absorbing material 56 can be easily replaced. In the illustrated example, ribs 58 are formed on the outer surfaces of the first partition wall 42 and the second partition wall 44 so as to be engaged with the exhaust passage wall surface 30b to support the partition walls.

Since the pneumatic tool 10 of the present invention is provided with the Helmholtz-type silencing device formed as described above, noise transmitted from the exhaust passage to the outside can be reduced. Further, in principle, although the Helmholtz resonance has one hole for one resonance chamber, it is also determined that a noise reduction effect can be obtained when a plurality of holes are provided.

Although the above description is directed to the embodiment in which the present invention is applied to a belt type grinding tool, the present invention is not limited thereto, and can be widely applied to a pneumatic tool that performs exhaust gas from a pneumatic motor and has an exhaust path. .

10‧‧‧ pneumatic tools

16‧‧‧Shell

18‧‧‧Air motor

20‧‧‧Motor room

22‧‧‧Motor storage unit

26‧‧‧Exhaust port

30‧‧‧Exhaust road

30b‧‧‧Exhaust road wall

36‧‧‧Train component for exhaust direction change

42‧‧‧1st dividing wall

44‧‧‧2nd dividing wall

46;48‧‧‧Resonance Room

50‧‧‧Exhaust passage

54‧‧‧ hole

56‧‧‧Muffling materials

60‧‧‧ claws

Claims (10)

A pneumatic tool having a Helmholtz-type silencing device, comprising: a housing having: a motor chamber for housing a pneumatic motor; and an air supply path for supplying compressed air to the motor chamber, and An exhaust passage for the exhaust gas from the motor chamber to be discharged from the downstream side outlet toward the outside; and a sound absorbing member, the sound absorbing member being disposed in the exhaust passage along a longitudinal direction of the exhaust passage Providing, dividing the exhaust passage into a resonance chamber extending along a longitudinal direction of the exhaust passage, and an exhaust passage adjacent to the resonance chamber and extending toward the longitudinal direction Separating from the resonance chamber, receiving exhaust gas from the motor chamber, passing the exhaust gas toward the downstream side outlet, and the sound absorbing member is provided with a hole communicating with the exhaust passage and the resonance chamber. The hole and the resonance chamber constitute a muffler chamber that resonates with Helmholtz. A pneumatic tool having a Helmholtz-type silencing device according to claim 1, wherein the exhaust passage extends linearly from the downstream side outlet toward the motor chamber toward the upstream side, and the sound absorbing member is The downstream side outlet is inserted into the exhaust passage toward the upstream side having the motor chamber, and the exhaust passage is partitioned into the resonance chamber and the exhaust passage. The Helmholtz type elimination as described in item 2 of the patent application scope In the air tool of the sound device, the sound absorbing member has a plate-shaped partition wall extending linearly from the downstream side outlet toward the upstream side having the motor chamber in a state of being inserted into the exhaust passage. The peripheral edge of the partition wall is engaged with the exhaust passage wall surface on which the exhaust passage is drawn, and the exhaust passage is partitioned into the resonance chamber and the exhaust passage, and the hole is provided in the partition wall. A pneumatic tool having a Helmholtz-type silencing device according to claim 3, wherein the sound absorbing member has a plate-shaped second partition wall, the second partition wall and the plate-shaped portion The partition walls are spaced apart from each other and are parallel. When the sound absorbing member is inserted into the exhaust passage, the peripheral edge of the second partition wall is engaged with the exhaust passage wall surface on which the exhaust passage is drawn. The partition walls respectively form a first and second resonance chambers between the exhaust passage wall surfaces, and the exhaust passages are drawn between the two partition walls to allow the second resonance chamber and the exhaust passage It is connected by a hole formed in the second partition wall. A pneumatic tool including a Helmholtz type muffler according to claim 4, wherein the first and second resonance chambers communicate with each other via a communication passage that traverses the exhaust passage. A pneumatic tool including a Helmholtz type muffler according to claim 4, wherein the muffling member has a connecting wall that connects the downstream end portions of the two partition walls. The Helmholtz type elimination as described in item 5 of the patent application scope The air tool of the sound device, wherein the sound absorbing member has a connecting wall that connects the downstream end portions of the two partition walls. A pneumatic tool having a Helmholtz-type silencing device according to claim 7, wherein a space portion defined by the connecting wall and the two partition walls is provided in the exhaust passage. There is: a sound absorbing material that allows exhaust gas flowing from the upstream to the downstream to pass through, and performs muffling. A pneumatic tool having a Helmholtz-type silencing device according to any one of claims 1 to 8, wherein the housing is provided with an exhaust pipe, and the exhaust pipe system defines the Exhaust road. A pneumatic tool having a Helmholtz type muffling device according to claim 9 wherein the exhaust pipe system is detachable from the housing.