JP2003025250A - Impact tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce vibration and noise and lengthen the life of an impact tool by insulating transmission in the radial direction of vibration generated by collision with a hammer, a middle piece, a tip tool of the impact tool driven by a motor and a workpiece and performing impact crushing work or the like. SOLUTION: A low rigid member layer 30 such as an elastic member layer or a resin member layer is disposed at least in a part between a cylinder 15 and a cylinder case 13.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an impact tool which is driven by an electric motor and carries out work such as impact crushing.

[0002]

2. Description of the Related Art Impact tools for work such as impact crushing generate a lot of vibration and noise during work. Various diseases due to vibration transmission to the human body, noise pollution to workers and surroundings, fatigue damage of various parts due to vibration, etc. Is occurring. As a measure against such a problem, for example, a vibration isolating member such as rubber is arranged between the grasping portion and the main body to reduce the vibration transmission to the operator.
Further, as another example of countermeasures, there is an example in which a damper is arranged in the reciprocating direction of the intermediate piece or the tip tool to buffer the shock in the reciprocating direction.

The basic operation of the impact tool and the outline of the prior art will be described below with reference to FIG. 2, which is a sectional view of the conventional impact tool.

The drive shaft 8 fixed to the electric motor 9 is rotated by the rotation of the electric motor 9, and the crankshaft 5 to which the gear 6 is attached via a pinion 7 provided at one end of the drive shaft 8 Rotate. The rotation of the crankshaft 5 causes the piston 4 to reciprocate in the cylinder 15 via the connecting rod 11 and the piston pin 12 attached to the crankshaft 5. Due to the reciprocating motion of the piston 4, the air pressure in the air chamber 19 formed by the piston 4, the striker 3, and the cylinder 15 changes, and the change in air pressure causes the striker 3 to move.
Reciprocates. The striker 3 collides with a meson 2 arranged in the cylinder 15 for the purpose of an oil seal and the like, and the meson 2 collides with a tip tool 16, and the tip tool 16 crushes a work material such as concrete not shown. And so on. Reference numeral 20 is a seal member for preventing outflow of lubricating oil (not shown) inside the main body to the outside of the main body, 1 is a tip tool holding member for holding the tip tool 16, 13 is a cylinder case for accommodating the cylinder 15, etc., and 14 is a gear. 6, a crankcase for accommodating the crankshaft 5 and the like, and 10 a housing for accommodating the electric motor 9 and the like.

In the above-described impact tool, a large vibration is generated due to the collision of the striker 3 and the intermediate piece 2, the intermediate piece 2 and the tip tool 16, and the tip tool 16 and a work material (not shown) collide with each other. It is transmitted to the cylinder case 13, the crankcase 14, the housing 10, etc., and causes vibration and noise.

[0006] As a conventional measure for reducing the vibration and noise caused by the collision and transmission of the above-mentioned various parts, for example, the grasping part 17 and the crankcase 14 to which the grasping part 17 is attached and the housing 10 are prevented. The vibration member 18 is provided to reduce the transmission of vibration to the grasping portion 17.

There is also an example in which a damper 21 is provided between the intermediate element 2 and the cylinder 15 in order to buffer the shock in the reciprocating direction.

[0008]

In the case of the conventional impact tool described above, it is possible to reduce the vibration of the grasping portion 17 by, for example, performing vibration insulation of the grasping portion 17 by the vibration isolating member 18. In the case of the work, the operator grips the grasping portion 17 with one hand, and the other side with the body cylinder case 13
In many cases, the side handle (not shown) attached in the vicinity is gripped, or the main body is gripped directly.
The vibration of the body is directly transmitted to the worker.

Further, in the above-mentioned example in which the damper 21 is provided to absorb the shock in the reciprocating direction, the vibration transmitted in the reciprocating direction can be reduced, but the work material (not shown), the tip tool 1
6, the vibration generated by the collision of the intermediate element 2, the impact element 3, etc. in the radial direction to the tip tool holding member 1, the cylinder 15, etc. cannot be insulated, and then each component is passed through the cylinder case 13 etc. Vibration and noise are transmitted to the.

The object of the present invention is to solve the above-mentioned drawbacks and to effectively transmit the vibration generated in the radial direction in the vicinity of the vibration source due to the collision of the work material, the tip tool, the intermediate member, the impactor, etc. Insulation is intended to reduce the vibration of the entire product, reduce noise, and prevent fatigue damage to parts.

[0011]

The above object is achieved by disposing a low-rigidity member layer such as an elastic member layer or a resin member layer at least at a part between the cylinder and the cylinder case.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION An impact tool according to an embodiment of the present invention will be described below with reference to FIG. The same parts as those in FIG. 2 showing the conventional impact tool are designated by the same reference numerals, and the description thereof will be omitted.

A piston 4, a striker 3, and an intermediate element 2 are arranged in the cylinder 15 and slide in the cylinder 15. Cylinder case 1 is provided on the outer periphery of cylinder 15.
3 is normally fixed by press fitting, and as shown in the figure, the low-rigidity member layer 3 is provided between the cylinder 15 and the cylinder case 13.
0 is set.

By virtue of the above structure, the vibration generated by the collision of the impact element 3 and the intermediate element 2, the collision of the intermediate element 2 and the tip tool 16, etc. is caused by the inclination of the intermediate element 2 and the like.
5 to the cylinder case 13 from the cylinder 15
Insulation of transmission to the low rigidity member layer 30. As a result, vibration of various parts such as the casing is reduced, so that vibration transmission to the human body can be prevented and the life of various parts can be extended. Further, since one of the main factors of noise generation of the impact tool is generated by the vibration of the casing described above, the noise can be reduced by reducing the vibration of the casing. The material of the low-rigidity member layer 30 is most preferably an elastic member such as rubber, but other materials such as resin having lower rigidity than the materials of the cylinder 15 and the cylinder case 13 are effective. For example, if both the cylinder 15 and the cylinder case 13 are made of iron, the low-rigidity member layer 30 is effective even with a damping alloy. The thicker the low-rigidity member layer 30, the greater the effect. However, even if the low-rigidity member layer 30 is thin, it has the effect of reducing vibration and noise compared to when it is not installed. It has a sufficient effect if selected. Further, regarding the position where the low-rigidity member layer 30 is arranged, it is most effective to arrange the low-rigidity member layer 30 in the vicinity of the meson 2 as shown in the drawing. This is because the main vibration transmission path is transmitted from the meson 2 to the cylinder 15 as described above. Further, in this case, by performing centering of the cylinder 15 with respect to the cylinder case 13 at a position other than where the low-rigidity member layer 30 is provided, centering of the cylinder 15 and the above-described vibration and noise can be reduced. it can.

As described above, even if the low-rigidity member layer 30 is provided in a part between the cylinder 15 and the cylinder case 13 and is relatively thin, it is effective. No troubles such as increase, deterioration of mountability, misalignment of the cylinder, etc. occur, and a great effect can be obtained by making a small change.

In many cases, the cylinder 15 and the cylinder case 13 are usually fixed by press fitting. However, after the low-rigidity member layer 30 is provided, a place other than the place where the low-rigidity member layer 30 is provided. The effect is further increased by providing a gap in at least a part of the contact portion between the cylinder 15 and the cylinder case 13. In this case, it is desirable that the clearance between the cylinder 15 and the cylinder case 13 be such that the cylinder 15 and the cylinder case 13 do not contact each other.
Since it is necessary to fix the position of the cylinder 15, if there is a gap of about 10 microns corresponding to the clearance fit, it is effective. When the embodiment shown in FIG. 1, which is an embodiment of the present invention, is adopted, the effect is that the low-rigidity member layer 30 is a rubber ring having a thickness of 1 mm, the other cylinder 15 and the cylinder case 13.
When press-fitting the contact part of, the noise level at a distance of 1 m is reduced by 1.5 dB, and the vibration is 5 in the cylinder case 13 when vibrating.
2% and housing 10 35%. Further, when the low-rigidity member layer 30 is a rubber ring having a thickness of 1 mm and the other contact portion between the cylinder 15 and the cylinder case 13 is a gap of about 10 μm corresponding to a clearance fit, the vibration of the cylinder case 13 is 63 %, The vibration of the housing 10 is 40%
% Reduced.

Although an embodiment of a hammer for crushing a work material such as concrete has been mainly described above, a hammer drill capable of both drilling and crushing a work material as another embodiment is also shown. The present invention is applicable. In a hammer drill, in addition to the reciprocating motion of a piston, a striker, an intermediate piece, and a tip tool similar to a hammer, the cylinder rotates in the cylinder case together with the tip tool and the like around the center axis of the cylinder. Therefore, generally, a bearing member such as a ball bearing or a metal bearing is interposed between the cylinder and the cylinder case. Also in the example of the hammer drill, the main transmission paths of vibration and noise are transmitted from the cylinder to the cylinder case through the bearing member and further to the entire product. In the case of the hammer drill described above, a low-rigidity member layer made of an elastic member, a resin member, a vibration damping member, or the like is provided on at least a part of one or both of the bearing member and the cylinder or the bearing member and the cylinder case. This has the same effect. Also, if there is a place where the cylinder and the cylinder case are in direct contact with each other without the bearing member, it is not effective to dispose the low-rigidity member layer on at least a part of the place where the cylinder is in direct contact. Needless to say. The points to keep in mind when using the low-rigidity member layer are the same as in the above-mentioned example of the hammer. For example, regarding the material of the low-rigidity member layer, considering the material and structure of the bearing member, the rigidity is lower than that of the bearing member. The material should be selected.

[0018]

As described above, according to the present invention, the radius of vibration generated by the impact of the striker, the intermediate tool, the tip tool, the work material, etc. of the impact tool driven by the electric motor and performing the work such as impact crushing. By effectively insulating the transmission in the direction near the vibration source, the transmission of vibration to the entire product can be reduced and suppressed,
It is possible to provide an impact tool with low vibration, low noise, and long life.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of an impact tool of the present invention.

FIG. 2 is a sectional view showing an example of a conventional impact tool.

[Explanation of symbols]

1 is a tip tool holding member, 2 is an intermediate member, 3 is a striker, 4 is a piston, 5 is a crankshaft, 6 is a gear, 7 is a pinion, 8 is a drive shaft, 9 is an electric motor, 10 is a housing, 1
1 is a connecting rod, 12 is a piston pin, 13 is a cylinder case, 14 is a crankcase, 15 is a cylinder, 16 is a tip tool, 17 is a grasping part, 18 is a vibration isolator, 19 is an air chamber, 21 is a damper, 30 Is a low-rigidity member layer.

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Claims (3)

[Claims] 1. A piston driven by an electric motor and reciprocally driven in a cylinder via a crankshaft, a striker reciprocally driven by air pressure fluctuations in an air chamber provided between the piston and the striker, and the striker. An impact tool for performing work such as concrete crushing by reciprocating an intermediate tool that collides in the cylinder and a distal tool attached to the distal tool holding member by the collision of the intermediate core, wherein the cylinder and at least a part of the cylinder are An impact tool, characterized in that a low-rigidity member layer such as an elastic member layer or a resin member layer is provided at least at a part between the covering cylinder cases. 2. The impact tool according to claim 1, wherein the low-rigidity member layer is disposed near the intermediate member. 3. The impact tool according to claim 1, wherein a gap of at least 10 microns is provided between the cylinder and the cylinder case.